assess the feasibility of a standardized electronic diagnostic

TECHNICAL REPORT STANDARD TITLE PAGE

1. Report No. FHWA-RD-

4. Title and Subtitle

2. Government Accession No. 3. Recipient's Catalog No.

5. Report Date December 1993 ASSESS THE FEASIBILITY OF A STANDARDIZED

ELECTRONIC DIAGNOSTIC DEVICE FOR MAINTENANCE AND INSPECTION OF COMMERCIAL MOTOR VEHICLES 6. Performing Organization Code

7. Author(s) 8. Performing Organization Report No. Dan Middleton, John Rowe, Debbie Jasek, and Rodger Koppa

9. Performing Organization Name and Address Texas Transportation Institute The Texas A&M University System College Station, Texas 77843

10. Work Unit No.

3A4A1092

11. Contract or Grant No.

for the Trucking Research Institute Study No. DTFH61-92-C-00092

of the American Trucking Associations

12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered

Federal Highway Administration 400 Seventh St., S. W.

Washington, D.C. 20590

15. Supplementary Notes

· April1993 Intenm- September 1993

14. Sponsoring Agency Code

FHW A Contracting Officer's Technical Representative: Robert E. L. Davis

16. Abstract

Interviews with government and industry officials and a literature search provided the information for this report which investigated the feasibility of a standardized electronic diagnostic device for use by motor carriers in their maintenance operations and for use by roadside inspectors to identify safety and emissions problems on Class 8 vehicles.

17. Key Words Trucks, maintenance, diagnostics, safety

inspections, emissions inspections

18. Distribution Statement

No restrictions. This document is available to the public through the National Technical Information Service, 5285 Port Royal Road Springfield, Virginia 22161

19. Security Classif. (of this report)

Unclassified 20. Security Classif. (of this page)

Unclassified 21. No. of Pages

108

Form DOT F 1700.7 (8-69)

22. Price

APPROXIMATE CONVERSIONS TO Sl UNITS I APPROXIMATE CONVERSIONS FROM Sl UNITS

Symbol When You Know Multiply ~y To Find Symbol Symbol When You Know Multiply By To Find Symbol

LENGTH LENGTH

in inches 25.4 millimetres mm mm millimetres 0.039 inches in ft feet 0.305 metres m m metres 3.28 feet It yd yards 0.914 metres m m metres 1.09 yards yd mi miles 1.61 kilometres km km kilometres 0.621 miles mi

AREA AREA inl square inches 645.2 millimetres squared mm' mm' millimetres squared 0.0016 square inches inl ft2 square feet 0.093 metres squared m' m2 metres squared 10.764 square teet ft2

yd2 square yards 0.836 metres squared m2 ha hectares 2.47 acres ac ac acres 0.405 hectares ha km2 kilometres squared 0.386 square miles mi2 mP square miles 2.59 kilometres squared km'

VOLUME VOLUME ml millilitres 0.034 fluid ounces fl oz

fl oz fluid ounces 29.57 ~illilitres ml l litres 0.264 gallons gal gal gallons 3.785 litres l m, metres ctbed 35.315 cubic feet ft' ft' cubic feet 0.028 metres cubed m3 m, metres clbed 1 .308 cubic yards yd, yd' clbic yards 0.765 metres cubed m3

NOTE: Volumes greater than 1000 l shall be shown in m'. MASS

9 grams 0.035 ounces oz MASS Ill kg kilograms 2.205 pounds lb

Mg megagrams 1.102 short tons (2000 b) T oz ounces 28.35 grams 9 1b pounds 0.454 kilograms kg T short tons (2000 b) 0.907 megagrams Mg Jll TEMPERATURE (exact)

oc Celcius 1.8C + 32 Fahrenheit oF

TEMPERATURE (exact) I temperature temperature Of

oF Fahrenheit 5(F-32)19 Celcius oc _ ~ 0 32

40 80 98·8

120 160 ~12

temperature temperature 1 • • • 1 • , .j . 1 • • • . , f. , . , 1 1 , , , 1 I ~ ( I I I I i 1 I I I

-40 -20 0 20 40 60 80 100 ~ 37 ~

TABLE OF CONTENTS

1.0 IN"TRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2.1 The Heavy Truck Industry . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. 2. 2 ·Carriers/ Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2.3 Manufacturers/Suppliers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.3 RESEARCH OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2.0 STUDY METHODOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.1 LITERATURE SEARCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2 INTERVIEWS OF INDUSTRY PERSONNEL . . . . . . . . . . . . . . . . . . . 5

2.2.1 Vehicle OEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.2.2 Vehicle Component Suppliers . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2. 2. 3 Vehicle Users -- the Motor Carriers . . . . . . . . . . . . . . . . . . . . . . 7

3.0 RESEARCH FINDINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3 .1 Literature Findings . . . . . . . . . . . . . . . . . . . . . . . . ~ . . . . . . . . . . . 9 3.2 Interview Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3. 2.1 Vehicle Electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.2.2 Vehicle Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.2.3 Vehicle Regulatory Environment . . . . . . . . . . . . . . . . . . . . . . . . 17 3.2.4 Vehicle Diagnostic Techniques ......................... 27 3.2.5 Vehicle Manufacturers .............................. 29 3.2.6 Vehicle Component Suppliers . . . . . . . . . . . . . . . . . . . . . . . . . . 30 3. 2. 7 Vehicle Users -- the Motor Carriers . . . . . . . . . . . . . . . . . . . . . . 31

4.0 RESULTS AND ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

4.1 COMMUNICATION REQUIREMENTS AND STANDARDS ......... 37 4.1.1 Parameters to be Monitored ........................... 37 4.1.2 Data Communications Standards . . . . . . . . . . . . . . . . . . . . . . . . 39

4.2 HARDWARE REQUIREMENTS AND STANDARDS .............. 40 4.2.1 On-Board Devices ................................. 40 4.2.2 Off-Board Devices ................................. · 41 4.2.3 Diagnostic Device Connections . . . . . . . . . . . . . . . . . . . . . . . . . 42

4.3 DIAGNOSTIC DEVICE OPERATOR INTERFACES ............... 45 4.4 TECHNICAL FORECAST OF "TOMORROW'S TRUCK" . . . . . . . . . . . 46

v

TABLE OF CONTENTS (Continued)

5.0 RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

5.1 POTENTIAL FOR OTHER SENSORS . . . . . . . . . . . . . . . . . . . . . 51 5.2 SAE/TMC STANDARDIZATION EFFORTS . . . . . . . . . . . . . . . . . 51 5.3 DIAGNOSTICS FOR ROADSIDE INSPECTIONS .............. 53 5. 4 FUTURE TASKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Appendix A Annotated Bibliography Appendix B Diagnostic Tool Information

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LIST OF FIGURES

1. Representative Questions for Vehicle Manufacturers and Component Suppliers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2. Representative Questions for Motor Carriers . . . . . . . . . . . . . . . . . . . . . . . . 8 3. Schematic of Networking Electronic Devices ........................ 48

LIST OF TABLES

1. Current Status of Electronics on Heavy-Duty Trucks . . . . . . . . . . . . . . . . . . . 16 2. Analysis of Items of Safety Inspection for Heavy

Commercial Vehicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 3. Antilock Brake Diagnostic Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 4. Summary of Carrier Interviews ................................. 34 5. Comparison of Diagnostic Codes by Component . . . . . . . . . . . . . . . . . . . . . . 38 6. Heavy-Duty Diagnostic Connectors Before Standardization ................ 43 7. Heavy-Duty Diagnostic Connector Location ......................... 44 8. Forecast of Heavy-Duty Truck Electronics . . . . . . . . . . . . . . . . . . . . . . . . . . 49 9. Potential Additional Parameters to be Measured on Heavy Trucks . . . . . . . . . . . 52 10. Comparison of SAE, Bosch, and ISO Heavy Duty Vehicle Serial Data

Communications Standards .................................. 76 11. STE/ICE Test Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

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EXECUTIVE SUMMARY

This study evaluates the feasibility of a standardized electronic on-board diagnostic (OBD) device which could be used by roadside safety and emissions inspectors as well as by carriers in their normal maintenance operations. The study is based on the premise that the number of multiple sophisticated electronic systems will increase on heavy commercial trucks of the future. Research objectives of this first task were: determine the technical sophistication and current costs of vehicle diagnostic equipment now in use, identify examples of local enforcement jurisdictions' application of such systems, determine the extent to which existing equipment can satisfy maintenance and inspection requirements, determine technological improvements necessary to bring equipment to the marketing stage, and determine the time anticipated for developing and testing the acceptance of the systems. Research objectives were achieved by meetings with knowledgeable trucking industry and agency personnel and through a comprehensive literature search.

The U.S. OEM truck producers, with one exception, function as systems integrators of supplier components, in other words, as merchant assemblers of other companies' parts. Traditionally, it has been considered vital to most of the major component suppliers to maintain a strong marketing effort to the truck user in order to ensure that their components have been identified and requested upon the sales order by the purchasing customer ordering from the OEM.

Electronics have made significant inroads onto the heavy-duty commercial vehicle. As recently as 1986, there was almost a complete absence of microelectronic technology on the heavy-duty vehicle. In contrast, in 1993, there are several electronic systems and applications either on the vehicle or available from component suppliers or under development. This is because electronics have offered the following advantages to the suppliers and producers of the vehicle: competitive pricing, vehicular weight reductions from electronic versus competing pneumatic and mechanical systems, improved reliability over earlier versions, flexibility by using a modular design concept, and improved effectiveness for highly technical applications.

In addition to the electronic controls currently used in engine and drivetrain components, there is expected to be additional significant penetration into other vehicular systems. Included as possibilities for emerging applications are: engine cooling system control, brake by wire, traction control, retarders, tire inflation pressure monitors, driver safety controls, proximity detectors for collision avoidance, driver comfort controls, and offboard communications and navigation. Of the plethora of opportunities for new systems, it is likely that there will actually be between three and seven "intelligently" controlled electronic devices on the vehicle. They will probably include the following: engine, transmission, brakes, retarder, the instrument cluster, a trip recorder, and an off-board communications device.

A network will be required if these electronically controlled devices are to share information. The benefits of this networked sharing of information include: elimination of

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redundant sensors, simplified wiring, coordinated driveline components (engine, transmission, and brakes) to improve safety and efficiency, and single-point data collection for diagnostics.

The heavy truck industry has been faced for some time with the challenge of communicating among a number of existing and planned electronically controlled components sourced from different manufacturers on the heavy truck vehicle. As a result, lengthy joint efforts to establish recommended practices in the communications area by the Society of Automotive Engineers (SAE) and The Maintenance Council (TMC) of the American Trucking Associations have developed a communications standard that is present on most heavy vehicles today. These recommended practices for communications on the heavy vehicle are: 11708--Serial Data Communication Between Microcomputer Systems in Heavy Duty Vehicle Applications; Jl587--Recommended Practice For Electronics Data Interchange Between Microcomputer Systems in Heavy-Duty Vehicle Applications; and J1922--the interim standard for drivetrain communications until the high-speed data link (Jl939) is available.

Dedicated diagnostic devices that interface with these communications protocols are both hand-held (portable) and console-based. All of the tools include at least several of the following features: They read the standard J1587 parameter identifier (PID) encoded diagnostic data; they read and write proprietary manufacturer's data that is not defined in the SAE Jl587 standard; they provide some capability for component parameter programming at either or both the cu·stomer level and the dealership level; they provide for controlled program modification both for recalls to correct defects as well as improved controller operation for improved vehicle performance.

Hand-held tools have the advantages of being relatively inexpensive, providing a "standard" tool that can be modified for manufacturer-specific items using cartridges. Disadvantages include the problem that generic cartridges for the tools are not as effective as component-specific cartridges. Most of the tools are based on proprietary computer design, limiting the ability to add software routines. Real capabilities for diagnosis require the specific manufacturer cartridge applicable to the component(s).

PC-based diagnostic tools are based on an "open" computer design which provides a multitude of additional optional computer hardware and software features on the tool. They have the additional advantages of supporting very sophisticated diagnostic programs, have more potential when used as a generic tool, and have the potential extended to many

, computer component suppliers to provide useful products. Their real capability for diagnosis still requires a manufacturer's program.

Currently, the only diagnostic logging function that is available from the manufacturers and suppliers in the heavy truck industry is the ability to store occurrences of fault or malfunction codes in the memories of their specific electronic control units (ECU's) or microprocessor-based· controllers. There is no generalized logging device that is capable of functioning in the manner of an engine or body computer as in the passenger car.

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Potentially, the vehicle recorder could provide the on-board function for logging of vehicle parameters. However, market penetration of recorders is currently limited--approximately 10 percent of existing and new vehicles. Further, the recorder is limited by its role of logging vehicle and driver productivity data which tends to occupy most of its memory as well as its design.

For roadside emissions inspections, actions of the California Air Resources Board (CARB) must be considered in light of their possible future applications to heavy vehicles. The CARB currently regulates gaseous emission levels from small to mid-size vehicles ranging from passenger cars to larger ·vehicles up to 8,500 lb gross vehicle weight rating (GVWR). Section 1968.1 of Title 13, California Code of Regulation (CCR), entitled Malfunction and Diagnostic System Requirements -- 1994 and Subsequent Model-Year Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles and Engines' (OBD II) establishes parameters that must be monitored (on gasoline engines) and which, upon detection of a problem, must generate a fault code and illuminate a malfunction indicator light (MIL).

These apply to gasoline engines, but given the aggressiveness of the CARB, it is anticipated that diagnostic system requirements for diesel engines will be deliberated soon. When that happens, the systems integrity monitoring currently required by OBD II will probably be included. The Environmental Protection Agency (EPA) has recently requested comments on rulemaking for vehicles up to 14,000 lb GVWR which appears to be very similar to that adopted by the CARB. It is expected that future regulations on emissions for diesel engines from both of these organizations will be extended into the heavier weight classes.:

Efforts aimed at diagnostics hardware standardization on Class 8 vehicles that have occurred over· the past 5 years include the current connector and its location. The industry has settled on the six pin connector manufactured by Deutsch. Its standard location is inside the cab near the left kick panel. This facilitates being reached by inspection (or maintenance) personnel standing on the ground on the driver's side of the vehicle.

It is recommended that free-market heavy truck standardization efforts be continued through the SAE and TMC activities. Past and continuing efforts are expected to develop standard data links, data protocols, a standard diagnostic connector, and a common connector location. A standard diagnostic tool should be based on an open hardware and software platform in order to minimize the development costs and eliminate any supplier advantages. The optimal platform would be based on the "IBM PC" standard using a generic set of software standards based on MS-DOS and WINDOWS.

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Chapter 1.0: Introduction

CHAPTER 1

INTRODUCTION

1.1 OVERVIEW

This study evaluated the feasibility of standardized on-board electronic diagnostic (OBI) systems which could be used by roadside safety and emissions inspectors·as well as by carriers in their normal maintenance operations. The study is based on the premise that the number of multiple sophisticated electronic systems will increase on heavy commercial trucks of the future. These systems include electronically controlled engines and anti-lock braking systems. These systems will have on-board diagnosis and fault logging capabilities to generate and store fault codes that will be useful in identifying and correcting operational and performance problems. The study postulated that it would be useful to standardize the diagnostic capabilities of these systems and that diagnostic capabilities could improve the roadside safety and emissions inspection process.

1.2 BACKGROUND

1.2.1 The Heavy Truck Industry

Class 7 and Class 8 trucks are included in the category of heavy trucks. Class 7 units range from 26,001lb. to 33,000 lb gross vehicle weight rating (GVWR), whereas Class 8 trucks have GVWR ratings above 33,000 lb.

To assess the approximate importance of each of these segments, it is necessary to look at annual vehicle sales. There are approximately 90,000 sales of Class 7 units annually, and approximately 125,000 Class 8 sales. Further, the size of the market can be guaged by another statistic: the existing total GVWR Class 8 truck population is approximately 1. 2 million vehicles.

Most of the vehicles in these market segments are diesel powered. Class 8 vehicles are almost exclusively (99 percent) diesel powered. Class 7 exhibits about 75 percent diesel power penetration. For purposes of this study, stress has been placed on the capabilities and potentials for on-board standardized diagnosis for inspections and emissions for Class 8 diesel powered trucks.

1.2.2 Carriers/Operators

The users of heavy commercial vehicles can be stratified or segmented into several classes based upon the number of units owned and/or operated. A brief description of each of these segments follows.

The most visible segment of the heavy commercial truck market consists of a few highly influential users who represent a substantial percentage of the total market. These

1


users are very cost oriented. They consist of several large common carriers engaged in interstate commerce together with a number of the large vehicle leasing companies. Approximately 50 percent of the annual new vehicle sales are represented by these leasing companies. This segment is followed by a relatively fewer number of medium size fleets, who tend to follow the lead of the large fleets in terms of product selection criteria.

The final segment consists of a larger number of users, operating fewer vehicles each, down to individual owner operators who are less knowledgeable about the technical aspects of the product. These members of the last segment are apt to be more influenced than the larger carriers by the image portrayed by the product. The leasing companies represent a significant product source for vehicles within these last two segments. ·

With the market segmented as outlined above, it has been relatively easy to introduce new electronic products and thus increase the potential for digital microelectronic-based diagnostics. With the larger users, this has happened due to the financial incentive, whereas with smaller users it has occurred (to a much lesser degree) due to a diversity of interests. However, the vehicle original equipment manufacturers (GEM's) and major component suppliers have found that, to be profitable in . any segment, their products must either show a substantial benefit-to-cost ratio or have a very substantial image appeaL Further, introducing a defective product that is not immediately corrected in the large. fleet segment is very dangerous to the OEM or to the supplier because of the "close knit" relationship among the various users.

The existing base of commercial for-hire and private carriers and operators represents a wide range of usage. They run the gamut from the classic over-the-highway tractor and trailer units engaged in interstate commerce to the more limited regional commerce of onhighway and off-highway carriers of construction materials and raw materials for logging, agricultural, and mining operations. This variety of usage has created the need for a widely divergent series of vehicle designs and components.

1.2.3 Manufacturers/Suppliers

The nature of the heavy commercial vehicle market is unique within the motor vehicle industry. It is characterized by "pull" marketing through a series of independent and freestanding component suppliers who independently design and produce as well as directly market their products to the end-use buyer of the vehicle. Component suppliers run the gamut from several suppliers of diesel engines and others who supply transmissions and axles and still others who supply seats, brake systems and components, lighting, and so forth. Component suppliers include Cummins, Caterpillar, Detroit Diesel, Eaton, Rockwell, and Bendix. This is contrasted to the "push" type of supplier marketing solely and directly to the OEM that exercises the product design control that is a characteristic of the U.S. automobile industry and the rest of the world motor vehicle industry as a whole. Major domestic OEM's are Ford, Freightliner, Mack, Navistar, PACCAR, and Volvo/GM.

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The OEM truck producers generally function as systems integrators of supplier components; in other words, as merchant assemblers of other companies' parts. Their sales data books are voluminous compilations of lists of various options consisting of supplier components that the customer may specify on his/her sales order. Traditionally, it has been considered vital to most of the major component suppliers to maintain a strong marketing effort to the truck user in order to ensure that their components have been identified and requested upon the sales order by the purchasing customer ordering from the OEM.

Historically, the component suppliers to the heavy commercial vehicle producers have assumed ever increasing engineering and design responsibility for major areas of vehicle design. In the first half of this century, the major OEM' s manufactured and assembled their own complete and proprietary vehicles, whereas in the latter half of the century they increasingly became a horizontally integrated industry.

During the second half of the century, large increases in unit volumes of vehicle production opportunities occurred as a result of the development of the interstate highway program, creating an attractive large volume supplier market for components. The highway program also provided a de facto vocation and application standard for the entire country in the form of a single standardized driving environment. Competitive pressures for these components was one factor which led the component suppliers rather than the OEM' s to make the majority of the new investments. The second factor resulted from OEM' s being willing to allow suppliers to make inroads into this market when the alternative required significant investment by OEM' s to modify their existing competing component lines. Due to the. developing pull marketing atmosphere, component suppliers could aggressively seek the potential sales volumes of the entire U.S. market, not just the volume share restricted to any on~ OEM.

Further, the availability of widely usable components permitted the rapid growth of a series of nationwide truck producers who previously had been restricted to regional markets. These companies found it unnecessary ,to heavily invest in component production elements such as engineering talent, foundries, and forging shops. Rather, they concentrated on marketing image and the vehicle assembly manufacturing process.

Thus, the (horizontally integrated) heavy commercial vehicle production industry is unique within the American motor vehicle industry in that design control and specification of the product does not rest solely within the bounds of any single organization. Thus, a variety of often contradictory and conflicting interests and enterprise objectives need to be addressed during the design and production stages of the product life cycle as well as in the operation and maintenance phases of the product life. These all have a significant impact on the application. of advanced diagnostics to this product. It is speculated that the competitive position and demand for innovative electrical and electronics products, in the time frame of the next decade, at least, will continue to be a "pull through" activity generated by the suppliers dealing directly with heavy truck and commercial vehicle customers.

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1.3 RESEARCH OBJECTIVES

The Task A-1 objective included conducting a review of the technical literature and interviewing industry officials to .(a) determine the feasibility of diagnostic technologies and (b) define what should be monitored. These objectives were further defined by the following elements:

1. Determine the technical sophistication and current costs of vehicle diagnostic equipment now in use,

2. Identify examples of Federal, State, and/or local enforcement jurisdictions' application of such systems,

3. Determine the extent to which existing equipment can or cannot satisfy commercial vehicle maintenance and inspection requirements,

4. Determine the feasibility of technological improvements or breakthroughs that can bring diagnostic and vehicle interface systems to the marketing stage, if existing equipment cannot meet these requirements, and

5. Determine the time anticipated for developing and testing the acceptance of the systems.

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Chapter 2.0: Study Methodology

CHAPTER2

STUDY METHODOLOGY

2.1 LITERATURE SEARCH

A comprehensive literature search revealed a number of articles and other publications related to on-board diagnostics and roadside inspections. These included both public documents presented at industry and society meetings as. well as published documents and articles. Texas A&M University's Sterling C. Evans Library was the source of most of the publications used, either in printed paper form or as microfiche. The process began with a search of key words of the various computerized lists of authors, publication titles, and subject matter topics. Some of the key words and key word combinations used were: trucks, maintenance, diagnostics, safety inspections, and emissions inspections. These sources related to automotive and heavy truck diagnostics, microelectronic-based devices on heavy trucks, future trends of electronics, and existing and pending standards and regulations of various government bodies.

The search identified 45 documents that were of interest to this study and the stated research objectives. Upon review of all potentially usable documents, 14 were found to be relevant. These summaries are attached as Appendix A. The literature identified and summarized can be generally divided into three categories: 1) descriptions of research and development efforts, 2) identification of current and future needs, and 3) guidelines and solutions. Examples of literature in each of these categories are presented in the Findings section of this document.

2.2 INTERVIEWS OF INDUSTRY PERSONNEL

Most of the useful information gathered during this phase of the study was acquired by project personnel traveling to meet with knowledgeable personnel either in their offices or at conferences where several key individuals were available at one location. Conferences which provided these opportunities were the International Symposium on Motor Carrier Transportation in Williamsburg, Virginia, the Society of Automotive Engineers J1939 Committee meeting in Boston, Massachusetts, The Maintenance Council meeting in Kansas City, Missouri, and the SAE Truck and Bus Exposition in Detroit. Each provided the opportunity to meet with several of the key personnel who provided information needed for the study.

The contractor conducted interviews and meetings with various government and industry organizations to determine the currently available technologies and diagnostic equipment that are available and appropriate for this research. Organizations included: the Federal Highway Administration, the Commercial Vehicle Safety Alliance, the Society of Automotive Engineers, the Intelligent Vehicle/Highway System (IVHS) America Commercial Vehicle Operations Technical Committee, the National Highway Traffic Safety Administration, and the American Trucking Associations.

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2.2.1 Vehicle OEM

Discussions were included with OEM vehicle manufacturers, major and minor electronic component suppliers and a full range of operators of heavy commercial motor trucks. Interviews were conducted with all six of the major domestic OEM manufacturers of Class 8 vehicles. These were Freightliner, PACCAR, Navistar, Mack, Volvo/GM, and Ford. Interviews also included the four domestic engine suppliers (Caterpillar, . Cummins, Detroit Diesel, and Mack), three transmission suppliers (Allison, Eaton, and Rockwell), two axle producers (Eaton and Rockwell), and four ABS suppliers (Bendix, Eaton, Midland, and Wabco).

The interview process with the vehicle OEMs began with an. initial telephone call to the person thought to be the most helpful based on his/her current position and experience. This first call included a brief overview of the study, its objectives, and establishment of a tentative meeting date and time. The location was usually on-site at the OEM' s facility but the SAE meeting in Boston and the TMC meeting in Kansas City provided meeting opportunities as well. On-site meetings were typically held at Technical Centers. The meeting date was usually two to four weeks after the initial call. A follow-up telephone call one week prior to the actual meeting confirmed the meeting time and location, asked for directions to the OEM's location if needed, and provided clarification of the study's objectives if needed. The OEM representative reserved a meeting room on the established date and contacted others within the organization who should be involved in the meeting.

The meeting format varied widely, but it always began with the researchers providing a comprehensive summary of study objectives. The same general information was gathered from each OEM but questions asked by researchers were not always the same. A list of representative questions is included in figure 1. During the discussions,. some needed information was volunteered before the question was asked, causing differences in types of information gathered. Discussions were both "on the record" as well as "off the record" regarding the OEM and suppliers' .current and future product plans for the introduction of additional microelectronic-based devices as well as their strategies regarding provision of diagnostics for these devices. Predictions were usually based on the representative's position of some authority, although it was understood that company policy, consumer demand, or other factors could influence future directions in ways not fully apparent at the time of the interview.

2.2.2 Vehicle Component Suppliers

Researchers also interviewed several Class 8 component suppliers. Included were four domestic engine suppliers (Caterpillar, Cummins, Detroit Diesel, and Mack), three transmission suppliers (Allison, Eaton, and Rockwell), two axle producers (Eaton and Rockwell), and three ABS suppliers (Wabco, Bendix, and Midland). Finally, the major independent supplier of generic diagnostic tools, Micro-Processor Systems, Incorporated (MPSI), provided information on current and future diagnostic service tools. Some representative questions used in the interviews are shown in Figure 1.

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• What trends do you foresee in on-board diagnostics for truck engines over the next 5 to 10 years?

• What is· the future of generic test tools for heavy truck applications?

• What role will the J1939 high speed data link play on the vehicle?

• What on-board diagnostic capabilities are your customers requesting on truck engines?

• Are there any significant costs and/or benefits related to on-board diagnostics?

Figure 1. Representative Questions for Vehicle Manufacturers and Component Suppliers

The interview process with the vehicle component suppliers was planned and conducted in a manner that was very similar to the vehicle OEM interviews. It began with an initial telephone call to a person who had both the knowledge and the authority to speak for the company that produces the component. The first call included a brief overview of the study, its objectives, and establishment of a tentative meeting date and time. The location was usually on-site at the component manufacturer's offices, but follow-up meetings were conducted elsewhere. The time frame used to schedule the meetings was similar to that used for vehicle OEMs. The component manufacturers' representatives reserved the meeting room on tile established date and contacted others within the organization who should . be involved in the meeting.

As a result of this information gathering, more accurate predictions are possible of the penetration· of microelectronic devices in heavy trucks as well as the potential diagnostic device support for these applications. The existing parameters being measured as well as potential additional parameters for on-board diagnostic monitoring were determined .

2.2.3 Vehicle Users-- the Motor Carriers

The method used to ·identify motor carriers· for interview began with members of the AT A Foundation who were located near locations of other scheduled interviews such as OEM or component suppliers. In some cases where ATA membership was sparse, additional contacts came from interviewees or from local telephone directories. The National Private Truck Council (NPTC} provided a list of their members in three states representing three regions of the country. Finally, names of owner-operators were provided by the Independent Truckers and Drivers Association _of Baltimore. Researchers conducted interviews with the NPTC members and owner-operators by telephone.

7


Most of the on-site meetings with motor carriers were in locations near interviews with OEM or component suppliers. The time frame used to schedule these meetings was similar to that used for vehicle OEMs or component suppliers. The carriers' representatives reserved the. meeting room on the established date and contacted others within their organization who should be involved in the meeting. Meetings with larger carriers usually included the director of maintenance. A list of representative questions used in these interviews is included in figure 2. Questions asked participants varied, depending on the size of the organization, the number of different diagnostic systems, and the amount of time provided by carrier representatives.

• How many power units do you have that are equipped with on-board diagnostics?

• What type of diagnostic tools do you current! y use?

• What is the average diagnosis time for your shop without OBD? with OBD?

• What is the reaction in your company to on-board diagnostics?

• How do you feel about roadside inspections?

• Do you feel on-board diagnostics could be used to improve and reduce time spent on inspections?

Figure 2. Representative Questions for Motor Carriers

8

Chapter 3: Research Findings

CHAPTER 3

RESEARCH FINDINGS

3.1 LITERATURE FINDINGS

A comprehensive literature search revealed a number of articles and other publications related to on-board diagnostics and roadside inspections. The search identified 45 documents that were of interest to this study and the stated research objectives. Upon review of all potentially usable documents, 14 were found to be relevant. Summaries of these documents are attached as Appendix A. The literature identified and summarized. can be generally divided into three categories: 1) descriptions of research and development efforts, 2) identification of current and future needs, and 3) guidelines and solutions. Examples of literature in each of these categories are presented below.

Hames, et. al. <t> described the Detroit Diesel Electronic Control (DDEC) manufactured by the (then) Allison Division of General Motors (now Detroit Diesel Corporation). DDEC I, introduced in September 1985, was the first U.S. electronic engine control system for the heavy duty diesel trucking industry. The development of DDEC IT took advantage of advances in technology to integrate all control system electronics into a single engine-mounted, fuel-cooled electronic control module. Improvements and refinements to DDEC 1 included the on-board diagnostics that were introduced with DDEC I. These capabilities can be categorized into three areas: self diagnostics, engine system protection, and engine performance diagnostics. Spivack <2> documented a research and development effort by West Coast Research for the U.S. Army Tank-Automotive Command to provide a differential transducer that could be used for engine diagnostics.

The automation of various components of the heavy duty diesel vehicle were addressed by several authors. Efforts to automate the preselection of vehicle· gearboxes by Scania were detailed by Holmelius <3>. Bender and Struthers <4> addressed efforts by the Allison Transmission Division of General Motors to develop an electronically controlled automatic transmission system utilizing advanced technologies in microprocessors, application specific integrated circuits (ASICs), sensors, actuators, displays, and direct electronic clutch pressure control. The integration of diagnostics for heavy duty diesel vehicles and the need for integration in the approach to diagnostics· was addressed by Lukich and Brandt <S>.

Foy <6> stated that real-time control systems have potential for many different applications in the trucking industry including an integrated control system. The author envisioned a total real-time control system for a vehicle that could be separated into four areas: trailer computer, cab computer, powertrain computer, and chassis computer. Malecki and Snyder (l) addressed the future of the trucking industry, the ramifications of current and pending economic, legislative, and safety issues on the trucking industry, and the use of electronic engine controls to address those issues. Bishel <S> also addressed the future of diagnostic equipment and the need for standardization.

9


Stepper <9> presented a synopsis of the serial data communications adopted in SAE Recommended Practices 11708, 11587, and 11922 as well as 11939 which was under development by the Truck and Bus Control and Communications Network Subcommittee.

3.2 INTERVIEW FINDINGS

3.2.1 Vehicle Electronics

Electronics have made a significant inroad onto the heavy-duty commercial vehicle. As recently as 1986, there was almost a complete absence of microelectronic technology on· the heavy-duty vehicle. In contrast, today, in 1993, there are several electronic systems and applications that are now available on the vehicle. This is because electronics has offered the following advantages to the suppliers and producers of the vehicle:

• Cost versus Price. Due to the competitive price pressures . on the commercial vehicle manufactured in the United States over the last seven years, most systems installed on commercial vehicles have had to continually be much lower in cost than comparable systems in the preceding generations of product as measured in constant dollars.

• Weight. Introduction of increased usage of microcontroller-based electronics has led to numerous relatively minor system component weight reductions over existing pneumatic and mechanical systems sufficient to balance out an increased level of sophistication and number of applications installed on the vehicle.

• Reliability. The advancements in microelectronic technology were eventually expected to lead to improved component reliability over then-existing electrical, pneumatic, and mechanical linkage controls and instrumentation.

• Flexibility. The increase in electronics-based features made it possible to provide segmented product features at a series of standard and optional levels from the same basic product design. System designs and functions were often structured in a modular fashion providing a degree of latitude to adapt to various customer demands and product "personalities."

• Effectiveness. Electronics can be more effective than some of their mechanical counterparts, as in engine fuel injection control where they also overcome the longterm mechanical "wear" problems previously encountered. Sophisticated systems such as anti-lock braking systems would not be feasible by any means other than by digital electronic systems.

The major areas currently using or expected in the near future (by the year 2000) to incorporate an electronics-based design on the heavy commercial vehicle include the following:

• Powertrain controls including 1) engine controls, 2) transmission controls,

10


3) engine protection and shutdown, and 4) vehicle speed controls; • Electrical power generation, distribution, and lighting; • Vehicle Trip Recorders; • Electronic-based displays, monitors, and instrumentation; • Engine cooling systems control; • Brake application anti-lock controls; • Traction controls and vehicle weight measurement; • Retarders; • Tire pressure monitoring; • Electronic steering control; • Driver safety controls; • Collision-avoidance; • Driver comfort controls (HVAC, Radios, etc.); and • Off-board communication and navigation.

Brief descriptions of each of these microelectronic-based applications follow.

Powertrain Controls. Electronic systems are especially important for engine management and controls. These systems are intended to inject the optimum fuel quantity into tJte engine under all operating conditions. Precise control of the injected fuel quantity benefits the operating performance of the vehicle, maximizes the fuel-economy of the vehicle and reduces emissions to the benefit of the environment. The sensors required to control the combustion cycle also permit the controller to provide engine protection and shutdown as well as vehicle speed controls.

For transmissions, electronic controls have to optimally control the gearshift points and correctly select the shift sequence. Benefits include variable gearshift points, comfortable shifting, and jerk-free shifting reducing powertrain stresses. Acceleration with no interruption in power flow represents an improvement in comfort and safety.

Electrical power generation, distribution, and lighting. By the end of the decade, "smart" switches will begin to appear on the heavy duty vehicle. These switches will activate many of the high-current lamps and actuators which are currently connected by long lengths of wiring between mechanical switches and the battery. These switches will utilize a multiplexed single wire· that ties together the switches and various devices on the vehicle. These types of systems will offer efficiency, protection, and intelligent control over very low cost devices on the vehicle. The "smart" in this case comes from integration of the processing of the signal received from the bus together with the power control output on a single chip or module. The complementary applications include integrating a sensor input such as a resistor, mechanical switch, or pressure sensor, with signal processing to develop a data signal to be sent on the multiplexed wiring to another device. A typical application is a If smart". solid state relay in the starter solenoid, integral with the starter' replacing the remotely mounted magnetic switch. Automatic disengagement of the starter and lockout options would then be possible to protect the starter from damage.

11


Vehicle Trip Recorders. Microelectronic trip recorders are the oldest of the intelligent devices, being initially introduced to the heavy truck industry in the late 1970's and early 1980's as replacements for tachographs. These units, while originally simply recorders of operational parameters such as vehicle speed or engine revolutions per minute (RPM), have evolved into on-board driver information systems recording driver productivity parameters such as time stopped and number of brake applications. These devices are expected to continue to develop by embracing such functions as 1) more memory allowing a greater degree of time resolution in the frequency of logging of existing parameters, 2) a complete capability as "crash recorders" with storage of a complete set of vehicle operational parameters immediately before and after a significant event such as an accident, and 3) additional functions where the large-scale storage on these devices begins to function as a generalized memory or "hard disk" role for a number of the other systems on the vehicle which have more limited memory.

Much of the functionality of trip recorders resides on the capabilities of the off-board software to analyze the data collected and logged on the recorder. They have become productivity measurement tools that are the foundation of vehicle. business systems. Advanced developments are expected in the nature of the off-loading of the data stored on the recorders. These currently run the gamut from cassettes, umbilical cords, and radio telemetry. As these develop they may make use of standard on-board data buses and diagnostic connectors.

Electronic-based Displays, Monitors, and Instrumentation. Displays are the most visible element in the ongoing technical revolution in electronics present on the heavy vehicle. Display options include light emitting diodes (LED) which replace incandescent light bulbs on a one-for-one basis; free format colored cathode ray tubes (CRT) such as those introduced on some passenger automotive models in the 1980's; fixed format vacuum fluorescent (VF) displays in a single or variety of colors as have been widely used on passenger cars; and fixed format liquid crystal displays (LCD) in either monochromatic or multiple color discrete. gauge plates of II glass 11

• LCD products can be based on either segment illumination or free-format dot matrix displays. ·

Other potential applications include gas discharge displays which are often called plasma displays as well as electroeluminescent displays (EL). However, both techniques have been plagued by inadequate brightness and high voltage requirements.

It is expected that existing mechanical analog gauges and displays will gradually be replaced with microelectronic gauge drivers. Eventually, by the end of the decade, more sophisticated free format displays based on LCD or similar technologies that are user configurable will become. more commonplace. Also, it is expected that sophisticated headsup display technology will be used for display of routine information such as speed and rpm as is currendy the state-of-the-art in fighter aircraft.

All of the above optional display techniques, regardless of their sophistication, require an intelligent microprocessor to receive the vehicle parameters. Upon receiving these signals

12

Chapter ·3: Research Findings

either directly from sensors or via a multiplexed wiring bus, the microprocessor functions as a gauge driver, converting the data into displayed elements.

Engine Cooling Systems Control. Microprocessor control of radiator fan drives and radiator shutters is increasingly being developed as a proprietary application system by a number of vehicle OEM' s. These systems will need data bus access to the engine controller sensors. They will be integral to vehicle performance and thus fault coding may need to be accessed by a diagnostic device.

Brake Application Anti-lock Controls. Electronically controlled anti-lock braking systems (ABS) typically provide benefits in an emergency situation by monitoring wheel rotation and modulating the brake pressure in order to prevent tire lock-up, or skidding. These systems are sophisticated and complex, and their usage is anticipated to be very widespread by 1995 or 1996. On September 28, 1993, NHTSA published a Notice of Proposed Rulemaking requiring ABS. Also, the largest U.S. vehicle OEM of Class 8 trucks has announced plans to include anti-lock brakes as standard equipment on its 1994 Class 8 vehicles. As ABS usage occurs, it will bring with it both the necessity and opportunity for automated inspection due to the inherent sophistication of ABS technology. Given that current on-board monitoring of ABS by the driver is only a "go" or "no go" message, there will be opportunities for external diagnostics applications. External diagnostic technology for both ABS and non-ABS braking systems will probably be available by 1995 or 1996 -perhaps based on dynamometers and infrared sensing.

Later in the decade will be the advent of electronic braking, or "brake by wire." The brake pedal will function as a switch or rheostat generating an electrical signal that will trigger brake actuation from air reservoirs mounted at or near the axles. Thus, the time delay in today's systems which are actuated by air pressure will be virtually eliminated. Initial installations will be redundant with air actuation backing up the electronic actuation. Benefits of faster timing will include reduced stopping distances, ability to apply differing amounts of torque to each wheel based on the load or weight on each brake, the ability to alter brake timing automatically as conditions and loads dictate, and the ability to measure and compare the heat generated by each brake in order to determine how much work each is doing and balance the braking among the various individual brakes. Electronic braking will permit the integration of intelligently controlled retarders into a complete braking system (mictoelectronically controlled retarders are described below.) Brake by wire will also introduce opportunities for complete electronic diagnosis of the braking system.

Brake by wire will require special data and power connections to the trailer for an integrated system. This requirement can be met by either a second trailer cable and connector as in Europe or by engineering modifications of the seven-pin trailer connector in order to extend a high-speed data bus to the trailer. To date, trailer installed ABS can be implemented with stand alone trailer axle installations. However, brake by wire will require real time integration of all vehicle configuration wheels into a total system.

13


Traction Controls. Electronically controlled automated traction controls are similar to ABS forming a safety related system that has the objective of preventing wheel spin during acceleration. It makes use of the same components as ABS for monitoring wheel rotation.

Retarders. Electronic retarders offer a perceptible reduction in stress for the driver during everyday vehicle operation. They also achieve improved operating economy through service life of the brakes. This is contrasted to ABS that functions only under a severe emergency braking condition. The deceleration effects of retarders are coupled electronically to the vehicle speed control systems.

Tire Pressure Monitoring. Tire inflation pressure monitoring and control of onboard inflation are application systems currently used in the military. It is expected that they will be widely introduced within the next five years (by 1998). These microelectronic applications are generally stand alone. However before the end of the decade, it is expected that optional display of the on-going pressures will be desirable on the electronic instrumentation in the cab at the driver's selection.

Electronic Steering Control. Electronically controlled power steering offers increased safety and driver operating comfort. Conventional servo-hydraulic steering systems possess transmission characteristics which represent a compromise between steering force inputs determined by the steering ratios of the mechanical steering components and the hydraulic booster components. At high speeds and under high lateral acceleration, the driver needs a direct feel of the lateral acceleration through the steering wheel while low steering effort is desired for comfort in turns at low speeds. El~tronically controlled systems will utilize a fluid proportioning valve which allows the pressure in the hydraulic reaction side of the system to be varied by the controller based on vehicle speed, front axle load, and lateral acceleration.

Driver Safety Controls. Driver safety controls are an eclectic mixture of selfcontained and autonomous applications on the heavy truck. These include radar guided backing and maneuvering at the dock, keyless vehicle entry and security systems, as well as interfaces to radar detection for regulated cruise control (similar to collision avoidance systems detailed below.)

Col~ion-Avoidance. Collision avoidance systems are electronically controlled proximity detectors. They utilize a high-frequency microwave or radar transmission and reception system together with intelligent controls that detect the rate of closure between the vehicle and potential obstacles detected by the radar system. The safety benefits of this type

. .

of system are obvious.

Driver Comfort Controls (Heating, Ventilation, and Air Conditioning- HVAC). HV AC systems are increasingly being designed with microelectronic control of blend air doors, water, and refrigerant valve controls. These systems use an extensive number of temperature and system condition sensors and then operate the system using parameter identification (PID) logic in order to converge upon a desired set point.

14

Chapter 3: ·Research Findings

Off-Board Communication and Navigation. Satellite and narrow~band FM two-way radio communication are already prevalent within the heavy truck industry. In most cases a digital electronic controller is used to handle th.e transmission and reception of data. These applications are generally stand-alone in nature. It is expected that extensive interfaces between the on-board ·data communications system on the vehicle data bus and the off-board communication system will be developed to routinely "broadcast" vehicle operational status. One application would use the keypad on the trip recorder or vehicle instrumentation system to input information for driver data to be transmitted to the fleet owner's office.

Navigation units will be self-contained. They will be either positional reference calculation units with their own mapping or they will be radio-controlled via LORAN-e or geostationary satellite radio transmission reception.

· In summary, the overall electronics industry has been the beneficiary of decreasing unit costs of their most basic raw material, semiconductor circuits or ·"chips". This has provided the ability for the automotive passenger car market to aggressively implement microprocessor-based electronic applications and thereby build a large volume base for the development of electronics components applicable to the commercial motor vehicle. · Commercial vehicle owners and ope~tors have thus become more familiar with the concepts and techniques involved in microelectronic technology as embodied in passenger car computer modules for engine emissions control. This familiarity, along with the success of "electronic engines" in heavy trucks, has done much to negate the initial acceptability problems with the reliability of on-board vehicle electronics.

Table 1 is a summary of project findings from the information-gathering process that illustrates the penetration of electronics into heavy truck applications versus mechanical, pneumatic, and other techniques. To distinguish between electronic and microprocessor-. based systems in the table, one should realize that "electronic" systems typically represent on/off or go/no go scenarios. Microprocessor-based systems are "smart" systems with memory of stored parameters via "look-up" tables. One example in passenger cars is electric seat controls. A "smart" control would have the capability of resetting to match a particular driver.

The historical role of most Class 8 OEM' s has been that of systems integrator, or more significantly, as ·a merchant assembler of supplier components. This role has not only continued but has accelerated with the introduction of advanced microelectronic controllers on various vehicle sub-systems.

3.2.2 Vehicle Maintenance

Heavy truck maintenance is performed by a wide variety of individuals and organizations. Much of the maintenance is provided by the traditional dealer or distributor organizations. These OEM and supplier franchised seiVice organizations are typically staffed with factory trained service technicians and are supplied with most, if not all, ·of the factory recommended service equipment including portable and console-based diagnostic service

15


Table 1. Current Status of Electronics on Heavy Duty Trucks

Micro-Processor

Application Mechanical Electronic Based Pneumatic Engine Speed Controls X X X Engine Protection X X X Electronic Engine Controls X Transmission Controls X X Vehicle Speed Controls X Automated Engine Cooiing Control X Automated Traction Control X Anti-Lock Braking X Tire Pressure Monitor X Controlled Assisted Steering X X X Control-over-driver-Asst. Steering Automatic Weighting X Axle Load Sensing X PTO Controls X X X Electronic Driven Discreet Gages X X Full Digital Displays X Vehicle History Recorders X Trip Data Recorders X Crash Recorders X Service Advisory Records X Diagnostic Link X Cab Environment (HVAC Controls) X X Seat Controls X X Lighting Controls X X Mirror Controls X X Blind Spot Detection X X Security--Anti-Theft X Remote Keyless Entry X X Communication System X X Security--Relocate Stolen Vehicle X Automated Load Advisory X Navigation CRT with Maps X Precis~ Location X

tools .. These dealers or distributors are typically authorized to sell and service the manufacturers' products within a given geographic area. They also spend most, if not all, of their effort in servicing products of a single (or multiple) manufacturer.

16


The carriers Qr vehicle operators often do much of their own maintenance in-house. Typically, a large fleet will have many maintenance centers or garages geographically distributed within the area serviced by the fleet.. These garages are staffed with technicians or mechanics who perform routine maintenance as well as diagnose and correct problems encountered by the fleets' drivers. Depending upon the make-up of the fleet, these technicians miglit find it necessary to provide service on a variety of vehicles from different manufacturers as well as a variety of components such as engines and transmissions from different component suppliers.

In both· the dealerships and the fleet maintenance operations, the operation typically segregates the problem definition or description function from the diagnosis or correction function. In a dealership operation, the problem is described by the operator or driver to a write-up man, often called a service manager or customer service technician. He writes a work order that describes the problem in terms of its obvious symptoms that is in tum forwarded to a mechanic who is assigned the problem diagnosis task.

The mechanic or service technician then troubleshoots the problems using the symptoms to determine the root cause of the problem. Where a complex electronically controlled device is. involved, it is generally routine practice to attach the electronic diagnosis tool to the vehicle or component in order to determine if on-board operating malfunctions have been encountered and stored as fault codes in the device. Thus, routine and problem maintenance of electronic devices generally involves one or more diagnostic tools.

Integration of service documentation including manuals, bulletins,and similar literature with the diagnosis device is a major need in the diagnosis function. The diagnosis function typically follows a "tree diagram" with alternate paths to be followed depending upon the conditions found by the mechanic such as the fault codes displayed by the diagnosis tools. This diagnosis tree data is generally provided in hard copy form in the manufacturer's · service documentation. Thus, there is often cross-referencing between books of service literature and the codes and conditions displayed by the diagnostic device.

3.2.3 Vehicle Regulatory Environment

Commercial motor vehicles over 10,000 lb GVWR must meet a variety of existing Federal Motor Vehicle Safety Standards (FMVSS) and Federal Motor Carrier Safety Regulations (FMCSR). These regulations are extensive and are enforced on the motor carrier through periodic· roadside inspections conducted by the FHW A and the States. NHTSA enforces its regulations through compliance testing and a review of the manufacturers' records. Currently, NHTSA is preparing its final report on the use of ABS on trailers; and, as of September 28, 1993, it had published a Notice of Proposed Rulemaking to require anti-lock brakes. These initiatives could lead to additional regulations in adv3:11ced braking systems.

The California Air Resources Board (CARB) currently regulates gaseous emission levels from small to mid-size vehicles ranging from passenger cars to larger vehicles up to

17


8,500 lb GVWR. Section 1968.1 of Title 13, California Code of Regulation (CCR), entitled "Malfunction and Diagnostic System Requirements-- 1994 and Subsequent Model-Year Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles and Engines" (OBD II) establishes parameters that must be monitored (on gasoline engines) and which, upon detection of a problem, must generate a fault code and illuminate a malfunction indicator light (MIL). These elements are included: catalyst (after-treatment of exhaust gases), heated catalyst (checks for proper heating of catalyst), misfire monitoring, evaporative system monitoring, secondary air system monitoring, A/C refrigerant leak monitoring, fuel system monitoring, oxygen sensor monitoring, Exhaust Gas Recirculation system monitoring, and a "Comprehensive Component Monitoring" category, which could include any electronic · powertrain component not otherwise covered.

Alt~ough the above requirements are for gasoline engines, CARB is also actively pursuing procedures to control diesel emissions. Currently the proposals for controlling diesel exhaust emissions are focused in three areas. The first area is the adoption of technology that forces emission standards. These standards are intended to lead to engineering augmentations of engine designs, including: cylinder redesign, turbocharger/supercharger redesign, improved fuel injection systems featuring electronic controls, exhaust gas recirculation, catalytic trap oxidizer, and particulate trap oxidizer development.

The second area is fuel regulations. The adopted measures regulate the maximum allowable sulfur and aromatic hydrocarbon fraction of diesel fuel to 0.05 percent and 10 percent by weight, respectively. These reductions could result in the reductions of NOx, SOx, and PM emissions. Promotion of efforts to design and test heavy-duty engines which operate with alternative fuels such as methanol.

The third area of concentration for controlling diesel exhaust emissions is an active inspection program, the California Heavy Duty Vehicle Inspection Program (HDVIP). This program would be conducted at California Highway Patrol (CHP) inspection and weigh stations, at random roadside locations,. and fleet locations. The type of test California uses is a snap-idle test, which takes 10 to 20 minutes. It is estimated by CARB that the HDVIP will eventually reduce the number of on-road excessively smoking heavy-duty vehicles by 57 percent.

A number of other states also currently operate heavy-duty vehicle emissions inspection programs. These states and the type of tests used by each include: Arizona (dynamometer), Colorado (snap-idle, acceleration, & lug-down), Connecticut (not specified), Maryland (snap-idle), Nevada (lug-down/snap-idle), New Jersey (snap-idle, acceleration), New Hampshire .(not specified), and Oregon (no-load idle). It is anticipated that other states will also adopt emi~sions regulations in the future as environmental and air quality regulations are enacted.

The EPA has recently requested comments on similar proposed rulemaking for vehicles up to 14,000 lb GVWR. It is expected that future regulations on emissions for

18


diesel engines from both of these organizations will be extended into the heavier weight classes. When that happens in an industry which is largely a horizontally integrated industry as in the Class 8 truck market, questions arise as to which entity is responsible for ensuring compliance. Obviously, the engine manufacturer must accept responsibility for emissions sensors which are resident within the engine environment, but at least one of the OBD II requirements does not fall within the engine manufacturer's purview. That is the refrigerant leak monitor.

No matter which party takes the lead in ensuring compliance with EPA rules, all of the monitored elements must generate standardized diagnostic codes and generate a signal which illuminates a MIL. The stored fault codes must be available to an inspector. performing a routine roadside inspection, preferably complemented with a "snapshot" of other pertinent data such as engine RPM, road speed, and various pressure, temperature, and/or voltage readings from the engine (or other appropriate system) at the time the fault occurred.

High impact organizations such as EPA and CARB are supplemented with a variety of State, county and municipal regulations that mandate vehicle compliance with additional and overlapping safety and emissions regulations. Local environmental regulations include additional rules on particulates, as well as the standard gaseous emissions of nitrous oxides, carbon monoxide, and hydrocarbons. An on-board system for diagnostics would have to support the widest possible number of these rules and organizations. These would include engine fault codes and ABS fault codes as well as possible additional parameters not currently monitored.

Current off-board tests of emissions in heavy-duty diesel trucks include opacity tests of exhaust smoke. As of April 1993, the eight previously mentioned States had adopted mandatory emissions inspection and maintenance programs for diesel trucks. California developed its own heavy-duty vehicle smoke and tampering inspection program composed of nine enforcement teams operating randomly along California highways, at fleet facilities, and at truck weight and inspection stations. The CARB has established <?Pacity standards to be used in these tests based on the manufacture date of the vehicle; opacity standards for older vehicles are less stringent than newer ones. In California, the opacity test results are based on the "snap-idle" test, but other States which use opacity measurements are not necessarily consistent with the California tests. The SAE is currently developing a joint government and industry-approved method for testing truck emissions at the roadside. Work on the draft standard, 11667, "Snap-Acceleration Smoke Test Procedure for Heavy-Duty Diesel Powered Vehicles," is continuing· and is expected to result in a final document that is approved by SAE by the end of the calendar year 1993°0>. Given the currently increasing activities in offboard testing, the increase in electronic engines, and the precedent established by OBD II of monitoring the integrity of components affecting emissions, on-board diagnostics for emissions applications should be imminent.

Table 2 represents a preliminary effort to identify items of safety inspections (at truck weight and inspection stations in the field, as contrasted to terminal or shop safety inspections). Each item was taken from a 1993 management edition of the Office of Motor

19

Table 2. Analysis of Items of Safety Inspection for Heavy Commercial Vehicles

SUBPART EQUIPMENT/FUNCTION FIELD INSPECTION SUITABILITY FOR ADVANCED PARA. TECHNIQUE TECHNOLOGY

B Lighting Devices, Reflectors, Electrical I

Equipment ..

393.9 Lamps Operable Observe operability 2- Unless no other reason for walk around

393.11-18 Lamp configurations for vehicle types Observe presence 3 -Must verify locations

393.19 Tum signals Observe presence/operability Operability 2, presence 3 -must verify locations

393.20 Clearance Lamps Observe presence 3

393.22 Permitted/prohibited Combinations Not a specific item 3

393.23 Lighting devices to be electri~ Observe presence 3

393.24 Requirements for headlamps and auxiliary Inspect condition, mounting 3 road lighting lamps Measure aiming 1 - State of the art

393.25 Requirements for other lamps (mounting, Inspect condition, markings 3 design) Observe operation 2 - Part of walk around Brake stop lamps

393.26 Requirements for reflectors Inspect condition, markings · 3

393.27 Wiring specifications Inspect condition, dimensions 3

393.28 Wiring protection Inspect condition 3

393.29 (Electrical) Grounds Verify presence 1 - Voltage readouts

393.30 Battery Installation Verify configuration, condition 2 to 3 (Electrical only - 1)

393.31 Overload Protective Devices Not inspected

Table 2. Analysis of Items of Safety Inspection for Heavy Commercial Vehicles (Continued)


393.32 Detachable Electrical Connections Inspect. condition, design 3

393.33 Wiring Installation Inspect condition 3

c Brakes

393.40 Required brake systems Verification 1to2 Service brakes Parking brakes Emergency provisions

393.41 Parking brakes Verify Operation/Release 2

393.42 Brakes on all wheels Verify presence 3

393.43 Breakaway and emergency braking Verify operation {part of Leakdown 1 Test)

393.44 Protection of front brake lines (buses) Design item, not usually inspected

393.45 Adequacy of brake tubing and hose Inspect condition 3

393.46 Brake tubing and hose connections Inspect condition 3

393.47 Brake lining (pads or shoes) Measure thickness, condition 1 - thickness

393.48 Brakes operative Verify operation I Check for presence of manual valve 3

393.49 Single valve operates all brakes Verification 3

393.50 Reservoirs required Leakdown test - verify integrity I Verify drain cock operability 3


---------


393.51 Warning devices and gauges Leakdown test - verify operation 1 to 2

393.52 Brake Performance Braking distance: not usually 1 if performed performed

i

D Glazing and Window Construction !

I

393.60-63 Glass presence, types, condition, window Verification 3 I

design, markings

E Fuel Systems

393.65 Location, installation, design of all fuel Verification of conformance 3 systems

393.67 Liquid fuel tank requirements Verification of conformance, 3 certain items (caps, vents, etc.)

393.69 Liquified petroleum gas systems requirements Inspected under 393.65

F Coupling Devices and Towing Methods

393.70 Coupling Devices/Towing Methods a. Tracking Not inspected b. 5th Wheel Assemblies Mounting (either Verification 3

half) Verification of operation 2 - special instrumentation Locking Verify position (lower) 3 Location Verification of design adequacy, 3

condition c. Full trailer towing Verification 3

d. Safety devices Presence, design Qualitative estimate 2 Strength



~~-------- ----------- -- -- - ------- ------ - - ---------


393.71 Coupling Devices/Towing Methods Driveaway-towaway Not often inspected 3 a. Number in combination Verify general conformance 3 b. Carrying vehicles on towing vehicle Verify general conformance 3

I

c. Carrying vehicles on towed vehicle Verify general conformance 3 d. Bumper tow bars on heavy vehicles Verify not present 3

I

e. Front wheels of saddle mount vehicles Verify general conformance 3 restrained

f. Orientation of towed vehicle Verify general conformance 3 g. Means required for towing Verify general conformance 3 h. Requirements for towbars Verify general conformance 3 ilk Saddle-mounts Verify general conformance 3 I. Kingpins for saddle mounts Verify general conformance 3 m. Additional requirements for saddle mounts Verify general conformance 3 n. Connection devices Verify general conformance 3

G Miscellaneous Parts and Accessories

393.75 Tires Tread, sidewall condition Measure and verify conformance 2 Load rating Verify general conformance 2(bar code) Pressure Thump or measure 1 to 2

393.76 Sleeper berth design and oceupant ptotection Verify general conformance 3

393.77 Heaters Prohibited types Check for presence 3 Specifications Verify general conformance 3

393.78 Windshield Wipers Verify presence, condition, 3 operation

393.79 Defrosting Device (if windshield) Verify general conformance 3

23


- ------- --- - -------------------------------------------------------------

SUBPART EQUIPMENT/FUNCTION FIELD INSPECTION SUITABILITY FOR ADVANCED PARA. TECHNIQUE TECHNOLOOY

393.80 Rear Vision Mirrors Verify presence, condition 3

393.81 Hom Verify operation 2

393.82 Speedometer Sometimes inspected on way to 1 bay

393.83 Exhaust System Location Verify conformance 3

393.84 Flooring (Integrity, contamination with Verify general conformance 3 flammables)

393.86 Rear end protection Verify general conformance 3

393.87 Flags on projecting loads Not usually an item of inspection

393.88 Television receivers (not visible to driver) Verify general conformance 3

393.89 Bus driveshaft protection Verify conformance 3

393.90 Bus standee line or bar Not usually and item of 3 inspection

393.91 Bus aisle seats Verify conformance 3

393.92 Bus emergency door marking and lamps Verify conformance (393.30 for 3 lamp) .

393.93 Seats, seatbelt assemblies, and anchorages Verify presence of belts, seat(s) 3 invokes FMVSS (49CFR571) anchored, etc.

393.94 Vehicle interior noise levels Not usually an item of inspection 1

H Emergency Equipment

393.95 Emergency equipment on power units Verify conformance 3 Fire extinguisher Spare fuses Warning devices


-- ------------ - -------- ------ ----------------- --


I Protection Against Shifting or Falling Cargo I

393.100 General rules Protection components Verify general conformance 3 Metal articles

393.102 Securement systems Tiedown assemblies Load binders and hardware Attachment to vehicle Winches/other fastenings Adjustability Verify conformance 3

393.104 Blocking and bracing Verify· general conformance 3

393.106 Front-end structure Verify presence 3

J Frames, Cabs, Body Components, Wheels, Steering, Suspension

393.201 Frames intact Inspect condition 3 Bolts, brackets intact, tight Frame rail flanges not bent or damaged Accessories bolted or riveted No holes in flanges except by manufacturer

393.203 Doors intact and working, emergency egress Inspect condition 3 possible

I

Cab mounts intact Hood fastened in place Seats securely mounted Front bumper intact and not hazard (protruding)

393.205 Wheels/rims not damaged or broken Inspect condition 2-3 Stud/bolt holes not damaged or elongated 3 Nuts or bolts missing or loose Inspect/check tightness 1 (tightness)


-·-~~-----

SUBPART EQUIPMENT/FUNCTION FiELD INSPECTION SUITABILITY FOR ADVANCED PARA. TECHNIQUE TECHNOLOGY

393.207 Axle mountings intact, not broken Inspect condition 3 Axles aligned Verify conformance 1 Adjustable axle locking pins intact, engaged Inspect condition 3 Leaf springs intact, not missing or shifted Inspect condition 3 Coil springs intact (not cracked or broken) Torsion bars intact (not cracked or broken) Air suspension:

Brakes get air before suspension Verify operation 1 Suspension levels vehicle Verify conformance 2-3 Air leakdown (3 psig in 5 minutes) Verify conformance 1

393.209 Steering wheel structurally intact Inspect condition 3 Steering lash Verify operation 1 Steering system: Verify conformance 3

U-joints not worn, faulty, repaired by welding Inspect condition 3 Gear box intact, no missing bolts or cracks Inspect condition 3 Pitman arm tight Verify conformance 2 Lock -to-lock capability Verify operation 1

Power steering system: All components intact and working Inspect condition/operation 1-2 Belt condition Inspect condition 3 No leaks Verify. conformance 2 Sufficient fluid in reservoir Verify conformance 1


Carrier regulations, published by AT A. These are all from the Code of Federal Regulations, Part 49, Subpart 393, U.S. Department of Transportation<1n.

For each item of inspection, the general technique currently used by field inspectors is identified. The background approach to the inspection process is generally that of the Commercial Vehicle Safety Alliance, but it should be recognized that different states even within CVSA have wide variations in the depth and numbers of items inspected. Much safety inspection consists of a very general walk-around by an experienced inspector, alert for conditions that he/she has learned are typically out of tolerance or a problem area. Where the entry in the Technique column reads, "Verify general conformance, II this level of inspection is meant. Unless the item is totally absent or noticeably damaged, no further scrutiny is attempted. For each item, a subjective rating is assigned concerning its suitability for advanced technology substitutes or assistance of the primarily visual and manual walk-around (and under) inspection procedure.

A rating of "1 II denotes an item suitable for replacement by advanced instrumentation or techniques such as bar coding. In some cases, such as headlamp aim measurement, good technology is already in use. A level "2" rating denotes an operation which might be aided by readouts or other kind of instrumentation, but payoff would be slight. Much of the time-consuming manual/visual inspection process remains. A Level "3 11 rating denotes an operation not suitable for mechanization or instrumentation, without a radical change in requirements or unforeseen ways in which the item could be assessed. This is only a preliminary study of the main items that make up a safety inspection, and further study or news of advanced technology will doubtless change some of these ratings. Still remaining to be studied are hazardous material inspection procedures, and those associated with the paperwork side of the weigh station process; ie. logbooks, bills of lading, permits, and so forth. Going beyond those items that are currently required by regulation to be inspected, future opportunities will exist for instrumentation as sensor sets become available and a desirable benefit-to-cost relationship exists. Some candidates are proposed later in this document.

3.2 .4 Vehicle DiagnoStic Techniques

Existing diagnostic techniques used to determine the source of problems in microprocessor-based truck components run the gamut from blinking lights to dedicated diagnostic tools. All of these techniques are based on the microelectronic device storing and/or repetitively communicating fault codes indicating the problem encountered on the unit.

Dedicated diagnostic devices are both hand-held (portable) and console-based. All of the tools ip.clude at least several of the following features:

• They read the standard J1587 parameter identifier (PID) encoded diagnostic data.

27


• They read and write proprietary manufacturer's data that is not defined in the SAE J1587 standard. This data is not generally available to the generic tool suppliers.

• They provide some capability for component parameter programming at either or both the customer level and the dealership level. These parameters include items such as engine RPM, power take-off (PTO) speed, idle shutdown time, engine horsepower, and transmission shift points.

• They provide for controlled program modification by reprogramming the electronic controller with authorization to provide new control logic and new calibration parameters. This function is used for both recalls to correct defects as well as improved controller operation for improved vehicle performance.

• Some of these tools provide for measurements of direct physical data on the vehicle and displays of these data. These vehicle signals include voltages, frequencies, and pressures.

• Some tools are capable of performing published diagnosis procedures as described in the manufacturers' repair literature. Additionally, they walk the mechanic through the procedure using "help" aids and diagnostic trees.

• A few are capable of performing the manufacturers proprietary diagnostic tests that are used for diagnosis of difficult problems.

• Some electronically integrate the display of all of the manufacturers technical manuals with the data acquired from the vehicle.

• Tools also continuously save a few seconds of vehicle data so that the technician can take a "snap shot" of the vehicle's data before and. after a problem occurs.

Hand-held tools have the advantages of being relatively inexpensive, providing a "standard" tool that can be modified for manufacturer-specific items using cartridges. Disadvantages include the problem that generic cartridges for the tools are not as effective as component-specific cartridges. Most of the tools are based on proprietary computer design, limiting the ability to add software routines. Real capabilities for diagnosis require the specific manufacturer cartridge applicable to the component(s).

PC~based diagnostic tools are based on an "open" computer design which provides a multitude of additional optional computer hardware and software features on the tool. They have the additional advantages of supporting very sophisticated diagnostic programs, have more potential when used as a generic tool, and have the potential extended to many computer component suppliers to provide useful products. They could still be hand-held units by using a "laptop" configuration, but it should ·be "ruggedized" to withstand the shop

28


or roadside inspection environment. Their prices range from moderate to expensive, depending on selection of available options. The computer will require at least a DX or DX2 processor and an add-on analog board. General cost figures are expected to range between two and four times the cost of existing hand held service tools. Their capability for complete diagnosis still requires a manufacturer's program.

3.2.5 Vehicle Manufacturers

Interviews were conducted with all six of the major domestic original equipment manufacturers of Class 8 vehicles. These were Ford, Freightliner, Mack, Navistar, PACCAR, and Volvo/GM. A number of common statements made by these manufacturers is provided below. These opinions represent a consensus among persons interviewed; some differences were expressed both among and within vehicle OEM' s interviewed.

• There is common acceptance and usage of the J1587/J1708 protocols for diagnostics; these are predicted to coexist with the high-speed communications protocol, J1939, for five to ten years after the introduction of 11939.

\

• Most vehicle OEM representatives agreed that the faster speed of J1939 is needed for a) "control" applications and b) more detailed diagnostic coding.

• Most agreed that the vehicle OEM' s should take the leadership role in coordinating multiple electronic systems on Class 8 trucks for communication purposes such as with diagnostic tools to minimize redundancy.

• One of the Class 8 OEM' s is distributing service literature to their distributors on CD-ROM using a Mackintosh system. This could complicate future usage of "PC-based" syste!lls in the shop or roadside environment as discussed later in this document.

• Three of the OEM's are currently using the interim J1922 high speed communications protocol for control applications~

• Orie. OEM predicted a "through the cab" diagnostic connector within five · years.· Pros and cons include the driver's privacy and the inspector needing

to enter the cab during inspection anyway.

• The current (1993) percentage of electronically controlled diesel engines in Class 8 tru.cks being installed by two major vehicle OEM' s is 80 percent for one and 95 percent for the other.

• The trend in electronic diagnostics is being driven by: a) a shortage in skilled mechanics, and b) rapid changes in vehicle design in response to emissions and safety regulations.

29


• Future applications of electronics on Class 8 trucks: trailer refrigeration systems, lighting systems, engine systems, tire inflation systems, and force transducers to sense loading conditions.

• Vehicle OEM's development of new technology is driven by the customer and/ or legislation.

3.2.6 Vehicle· Component Suppliers.

Four domestic engine suppliers (Caterpillar, Cummins, Detroit Diesel, and Mack), three transmission suppliers (Allison, Eaton, and Rockwell), two axle producers (Eaton and Rockwell), and four ABS suppliers (Eaton, Bendix, Midland, and Wabco) provided information for use in this study. Also, the major independent supplier of generic diagnostic tools, Micro-Processor Systems, Incorporated (MPSI), provided information on current and future diagnostic service tools.

Some general comments expressed by component suppliers are summarized below:

• All engine manufacturers have both proprietary and non-proprietary codes. Generic readers generally cannot access proprietary codes.

• All manufacturers of electronic engines secure parameters that could change the engine's torque and horsepower, and thus discourage tampering and consequent increased emissions to undesirable levels.

• All major engine manufacturers except one utilize independent suppliers of diagnostic hardware. The one exception manufactures its own.

• Many mechanics have been in a "parts changing" mode for many years and continue this with electronic components. So a majority of parts removed and tested are not conclusively defective, but many are returned to the supplier for replacement.

• In 1992, the leading manufacturer of ABS sold 36 percent of its units for general freight movement; in 1993 it is expected to be 60 percent. ''Brake by wire," possibly available by the year 2000, will offer much greater opportunity for on-board diagn~stics than current brake systems.

There is a consensus among the OEM's and suppliers that the market penetration of "smart" electronics will continue and will accelerate. As a consequence, the number of microprocessors on the vehicle will markedly increase by the end of the d_ecade. Further, there will be an accelerating trend toward the sharing of data among controllers. This should minimize the proliferation of redundant sensors on the vehicle such as engine speed sensors and vehicle speed sensors.

30


All of the OEM' s and the component suppliers have committed to the joint efforts of The Maintenance Council (TMC) and Society of Automotive Engineers (SAE) to incorporate standardized low-speed and high-speed data buses on the vehicle for communications, including diagnostic tools, in order to share operating and diagnostic data. Based on interviews conducted, there is an industry consensus to utilize a standardized connector in a standardized location (probably no later than 1994).

Because of the nature of the heavy truck market, the manufacturers and suppliers are forced into alliances in order to develop a functioning vehicle for the customer. It is expected that these trends toward cooperation and sharing will continue.

OEM and supplier dealership maintenance garages have not yet encountered the problems of training and investment in a wide range of diagnostic tools. Typically the type of maintenance brought to them is a difficult problem involving one of their nameplate units. Problems involving other manufacturers or individual component suppliers are generally routed to dealers for that nameplate or component. If the problem is not severe, it is typically handled by the mechanics in the fleet's garage.

Anti-lock Braking Systems. Comparison of the on-board diagnostic systems for antilock brake systems for Eaton, Midland-Grau and W ABCO indicates significant differences in the ways these component suppliers communicate fault information to maintenance and inspection personnel. More specifically, the codes used by each of these companies are unique to that company and are not standardized. One. common trait among the systems is that each company provides the capability of specifically identifying each sensor for each axle. Table 3 groups fault codes from each of these suppliers in order to demonstrate that some of the basic groupings are similar (even though fault-specific codes are different among manufacturers). Each group addresses one fault such as sensor failed or shorted. MidlandGrau specifies 0 _ as the fault code for this problem. The additional identifier isolates the location of the fault; for example, 01 indicates that the left sensor for axle 1 is the sensor that has failed or shorted.

3.2.7 Vehicle Users-- the Motor Carriers

A full spectrum of private and for-hire carriers was interviewed. These included the large for-hire carriers operating over 2,000 units down thr~ugh smaller regional and commodity-specific carriers, including some owner-operators operating one to 10 units. Large fleets included large less-than-truckload (LTL) carriers using van type cargo trailers; mid-size and small fleets included tanker operations and material haulers .

. During conversations with these carriers, several points became evident. The first was that a significant number of carriers do not have vehicles equipped with electronic engines, and thus have no experience with on-board diagnostics. This occurrence was more predominant for small to medium sized companies. The second point was that some fleets

31


Table 3. Anti-lock Brake Diagnostic Codes

Description Eaton Midland- WABCO Grau

Sensor failed open or shorted to ground 1*1 thru 1*6 01 thru 06 2-8-10 thru 2-8-15 and 2-9-0 thru 2-9-2

J 1922 communication link problems 8*8 2-8-3 and 2-8-5 2-8-9 thru 2-8-11

No fault or trouble found 6*6 00 2-0-0

System voltage is less than 9 volts 6*3 90

Power supply voltage is too high 6*4 92 2-13-8 and 2-13-9

Sensor failed, no signal 2*1 thru 2*6 11 thru 16 2-6-10, 2-6-11, 2-7-2, 2-7-3,

Signal quality poor or intermittent 7*1 thru 7*6 21 thru 26

purchase vehicles based on a limited range of specifications, generally becoming .comfortable with a particular set of engine, drivetrain and other component combinations. These fleet manage·ment personnel believe that their selected combination has served them well and will continue to do so for the foreseeable future. Thus, the problems of a wide range of engine, transmission, and braking components in their fleets is of limited impact in their maintenance functions. Several owners, chief executive officers, and maintenance supervisors remarked that maintenance operations were simplified by having a homogeneous fleet. The third and final point was that some of the companies that do have electronic engines have not purchased diagnostic devices. Those companies that have purchased diagnostic devices, usually purchase the equipment that is sold by the engine manufacturer.

There are other fleets, however, that are using a variety .of components and a variety of tools and find this extra expense and training to be a significant problem. The leasing companies are examples of this and have long supported standardization and trends to universal tools. Regardless of the tool or manufacturer, the typical fleet finds that it takes an average of 30 to 45 minutes to troubleshoot a specific problem. Training costs are practically insignificant, but the electronic intimidation factor is a recurring theme, which increases loss time and (unquantified) costs. Other negative comments from service personnel who had diagnosed electronic engine problems included a general resistance on the part of mechanics to change to electronics, and computer logic not allowing the mechanics' experience to be fully utilized.

32


Table 4 is a summary of carrier interviews conduct~ during the initial study period. Fleet size, commodity hauled, location, coverage area, and percent electronic engine usage were included in topics discussed. Results of these interviews indicate significant advantages of electronic engines over mechanical engines. Fuel mileage and tire wear were improved, possibly due to increased use of cruise control. It should be noted that cab type was a factor in fuel economy which was not always available from carriers interviewed. One carrier reported a 0.3 mpg advantage of conventional cabs compared to cabovers.

Operators and drivers stated that roadside inspections do not currently pose a major inconvenience. According to them, they can tolerate delays of 30 to 45 minutes, which is the average time required for this inspection. Most are interested in safe vehicles and willingly comply with roadside inspections because safety violations can occur even if pretrip maintenance has been performed. There is, however, a major concern as to whether the existing levels of inspector training are sufficient for the tasks involved. There were numerous anecdotal examples cited of inexperienced and/or unqualified inspectors delaying vehicles unnecessarily for long periods of time. Further, there are concerns on the part of the carriers as to whether a· standardized electronic diagnosti~ tool being used in roadside inspections would compound this problem if the inspectors cannot be trained to correctly inspect and diagnose problems.

Given the current interest in. transparent borders and other means of maintaining "just in time" delivery schedules, it was anticipated that the use of radio frequency for downloading inspection data would be attractive to carriers. However, there were numerous concerns expressed by owners and operators that a standardized diagnostic system might be used by regulatory personnel as a tool to "browse" the on-board electronic controllers. Inspectors could interrogate all stored faults "until they found something wrong" regardless of its significance to safety or emissions regulatory. compliance. To overcome this concern, industry standardization of codes and diagnostic devices must provide a segmentation or hierarchy of significance.

A portion of the information gathered during interviews pertained to possibilities of carriers and others participating in cost-sharing activities later in the study. Cost sharing could take the form of in-kind support through facility and/or personnel sharing. Given the sentiments of the few carriers included in the study to date, there appears to be little interest in entering into cost-sharing arrangements that offer them little economic advantage. Additional efforts should be aimed at a quantitative analysis of a much larger sample size. Incentives to participation must be clearly defined, however, and posed in a structured format before definitive conclusions can be drawn. This is the subject of Task A-3 and is further addressed in the Recommendations section of this document.

33


Table 4. Summary of Carrier Interviews

Carrier A B c D

Location MW SE NW E

Carrier Size Large Large Small Small

Coverage Area Worldwide us Local us

No. Power Units 10,000 40,000 14 172

Line Haul 4,000 N/A 14 1n

Pickup & deli very 6,000 N/A

Type Power Unit

Line Haul Volvo, Mack Freightliner, Ford, Freight liner, Paccar, Navistar Paccar Freightl iner Paccar, Volvo,Mack

Pickup & delivery Ford LN8000, C800 N/A

LTL, TL LTL Leasing LTL

No. trailers 30,000 29,000 20

Trailer style van van tanker longvan

Trailer type Freuhauf, Trailmobile, Pines, Wabash National

Cab type Conventional both

No. Elect. Engines 2, 715 28,000 14 80

Caterpillar 5

Cunnins 90 14

Detroit Diesel 2,600 6 on order 80

Mack 20

No. ABS Tractors 200 500 14 none

WASCO 0100

Bendix 100

Midland·Grau

Eaton

ABS Trailers 500 20

Auto Transmission none 0 none none

Transmission type Eaton Fuller Rockwell

Service Tool MPSI Prol ink 9000 MPSI - 500 Service DDEC OTC - 150 , Cat -75 Contracted V-Mac PC based

Trip recorders Few Tachographs

34


Table 4. Summary of Carrier Interviews (Continued)

Carrier E F G H

Location MW MW E E

Carrier Size Large Small Midsized Small

Coverage Area u.s. u.s. u.s. Regional

No. Power Units 9,700 180 968

Line Haul 3,600 180 n6 Pickup & delivery 9,700 122

Type Power Unit

Line Haul Paccar Volvo Navistar Ford

Pickup & delivery

LTL, TL LTL LTL LTL

No. trailers 34,400 200 3600

T,railer style Van Refrigerated Van reefer, box van Vans

Trailer type

tab type Conv.

No. Elect. Engines 850 162 850

Caterpillar 30 150

CI.IIIJiins

Detroit Diesel 10

Mack

No. ABS yes none yes

WABCO

Bendix

Midland-Grau

Eaton

ABS Trailers yes none yes

Auto Transmission none none

Transmission type

Service Tool ECAP, MPSI CompuCheck, Prol ink Celect, ECAP,

MPSI Prolink

Trip recorders none

35


Table 4. Summary of Carrier Interviews (Continued)

Carrier I J K

Location NW NW NE

Carrier Size Midsized Small Owner

Coverage Area u.s. Regional u.s. No. Power Units 520 106 1

Line Haul 520 106 1

Pickup & delivery

Type Power Unit

Line Haul 1

Pickup & delivery

LTL, TL TL Special

No. trailers 2,000 1

Trailer style Triple, Rocky Refrigerated Reefer van Mtn

Trailer type

Cab type both conv.

No. Elect. Engines 250 45 1

Caterpillar 80

Cunnins 160 26 1

Detroit Diesel 10 18

Mack 1

No. ABS none none 1

WABCO

Bendix

Midland-Grau

Eaton

ABS Trailers none none none

Auto Transmission none none

Transmission type

Service Tool OEM· supplied Celect L-10, Service contracted Curmins N-14, DDEC

Trip recorders

Legend: ? Data not available.

36

Chapter 4: Results and Analysis

CHAPTER 4

RESULTS AND ANALYSIS

4.1 CO:MMUNICATION REQUIREMENTS AND STANDARDS

The heavy truck industry is unlike the passenger car industry in that an inspector (roadside or otherwise) or maintenance technician cannot rely upon the vehicle manufacturer to provide an integrated system of diagnostics. The heavy truck industry is based upon a vehicle composed of many sub-systems or components which are manufactured independently by various independent suppliers. Potentially, each component with "intelligent" control or its own electronic control unit (ECU) comes with its own proprietary diagnostic hardware, codes, and procedures. Thus, an inspector attempting to gauge the operational functionality of one or more systems on the vehicle, or alternatively a heavy truck maintenance garage servicing a variety of vehicles, would have to maintain a wide variety of diagnostic devices.

Thus, based on the variety of applications and hardware on a heavy commercial vehicle, there is a potential opportunity to develop a standardized diagnostic terminal that eliminates the various unique hardware devices as well as minimize the potential costs of service technician and inspector training. This potential is limited, however, by the large number of suppliers and their needs to protect their own market niches by product differentiation as well as the relatively limited overall volumes as compared to the passenger car industry.

Cprrently, the only diagnostic logging function that is available from the manufacturers and suppliers in the heavy truck industry is the ability to store occurrences of fault or malfunction codes in the memories of their specific ECU's or microprocessor- based controllers. There is no generalized logging device that is capable of functioning in the manner of an engine or body computer in the passenger car. Potentially, the vehicle recorder could provide the on-board function for logging of vehicle parameters. However, market penetration of recorders is currently limited-approximately 10 percent of existing and new vehicles. Further, the recorder is limited by its role of logging vehicle and driver productivity data which tends to occupy most of its memory as well as its design.

4.1.1 Parameters to be Monitored

The population set for diagnostic. data is provided by the existing J1587 diagnostic codes provided by the vehicle manufacturers and component suppliers for their existing on-board electronic controllers. Examples of these diagnostic codes are shown in table 5 for engine and transmission suppliers. One problem in making this comparison is that the descriptions of (the same) faults vary widely among engine manufacturers.

In order to facilitate a complete on-board diagnostic capability to support all of the possible needs of roadside safety and emissions inspections, additional data will probably need to be logged at the point that a system fault is encountered. Examples are engine data such as RPM's, road

37


Table 5. Comparison of Diagnostic Codes by Component

Description Caterpillar Detroit Mack Cummins Allison Diesel

Excessive Engine Power 23-2

Vehicle Overspeed Warning 84-0 p 084 0 42 212Pace 241 Celect 11 PT Pacer

Low Fuel Pressure Warning 94-1 p 094 1

Low Oil Pressure Warning 100-1 p 100 1 Red Light 143 Celect 14 12 and Alarm

Very Low Oil Pressure 100-11 11 141 Celect

High Coolant Temperature Warning 110-0 p 110 0 Red Light 142 Celect and Alarm

Low Coolant Level Warning 111-1 p 111 1 Red Light 235 Celect and Alarm

Very Low Coolant Level 111-11 21 145 Celect

Engine Overspeed Warning 190-0 p 190 0 NA 234 Celect 13 PT Pacer

Intermittent Battery 168-2 p 168 1

Throttle Sensor Failed Low 91-8 21 12

Primary Shift Selector Mode Function Fault 23 13

Sump Oil Temperature Sensor Failed High p 175 3 212 Celect 33 23

Power Interruption 35 00

Proprietary Data Link Abnormal Frequency s 248 8 62

Controller bad device or component 254-12 s 254 12 235 Pace 352 Celect 23 PT Pacer

Personality Module Fault 252-12

11587 Data Link Bad Device or Component s 250 12 63 243 Pace 414 Celect

Shutdown Override Switch 74

Timing Sensor 34

Source: Engine and Transmission Manufacturers ·

38


speed, coolant temperature, .boost pressure, and fuel pressure when a cylinder misfire is detected. It is logical to collect and store this data in the specific component controller that controls the function because that controller is already wired into the specific sensor set to access and log the data.

Such· an approach may require a small proprietary controller/logger for any emission or safety system faults that are not currently addressed by a component supplier. An example of this type of condition could be the necessity to store the time and vehicle location of a refrigerant leak in the air conditioning system. There currently are few, if any, intelligent controllers on-board for these systems, so the vehicle manufacturer would have the opportunity to install an embedded controller for this type of fault logging. The other alternative is to utilize proprietary controllers such as some have for instrumentation gauge drivers, road speed governors, or shutdown systems.

4.1.2 Data Communications Standards

Existing Heavy Truck On-Board Communications Standards. The heavy truck industry has been faced for some time with the challenge of communicating among a number of existing and planned electronically controlled components sourced from different manufacturers on the heavy truck vehicle. As a result, lengthy joint efforts to establish recommended practices in the communications area by the SAE and TMC have developed a communications standard that is present on most heavy vehicles today. These recommended practices for communications on the heavy vehicle are:

11708--Serial Data Communication Between Microcomputer Systems in Heavy Duty Vehicle Applications. This is the hardware protocol for the low speed serial data link that describes the wire size, type· and length, electrical parameters and protocol for messages.

11587--Recommended Practice For Serial Data Communications Between Microcomputer Systems in Heavy Duty Vehicle Applications. This is the data format for the low speed data link. It is a software standard based on the 11708 hardware standard. It defines standard messages with a message identifier (MID) such as "190" for engine RPM and assigns numbers to components such as "130" for the transmission.

11922--The Interim standard for drivetrain communications until the high-speed data link (1 1939) is available.

The data bus itself is the single wire or set of wires used to transmit information between the electronic components or sub-systems of the heavy duty vehicle. The rate .of data transfer defined by the low speed bus or 11708 is 9600 bits per second. The high-speed bus, 11939, will transmit at a rate 10 to 20 times that of 11708, or in excess of 100,000 bits per second. It will be used· for speed-critical data exchange between components such as engines, automatic transmissions, and antilock brake systems .. Table 5 provides a partial list of the data being currently broadcast on the 11587/11708 data link and a comparison of how this varies by manufacturer.

Further, these industry groups are currently developing a new standard for recommended practice, 11939, which will be capable of handling real-time data. This standard is anticipated to

39


eventually replace the J1587 standard for communication of diagnostic information. J1939 will probably coexist with the slower Jl708/J1587 based data link used for information monitoring for the foreseeable future. The increasing penetration of intelligent electronic-based devices on the heavy duty vehicle will likely result in most if not all vehicles within the heavy truck market having one or more controllers with a data link capability. For at least the next 10 years, this capability will be solely based on J1708/J1587 design practices. Gradually, the higher speed real-time features of J1939 will penetrate the manufacturing base and will coexist with the slower diagnostic links. It is recommended that the J1708/J1587 data link standards and protocols continue to be the medium for transmitting diagnostic faults and system condition data to the off-board diagnostic devices.

Diagnostic Information Standards. There are two basic strategies for communicating diagnostic information to the inspector or maintenance technician. One is that the microcontroller on the vehicle transmits a "code" that is then used as an index into a table or list of descriptive messages that indicate a fault. This is the methodology that is followed in the passenger car industry and is also widely followed in the heavy truck industry.

The second approach is the use of a structured mess~ge. This type of message format is covered by the diagnostic message format developed by the ATA-TMC/SAE subcommittee for J1587, the recommended practice for serial data communications between microcomputer systems in heavy duty vehicle applications. It is a highly structured format for forty character descriptive messages.

An alternative to the structured message format is a free form textual message. However, this runs counter to the standardization of diagnostic message formats.

4.2 HARDWARE REQUIREMENTS AND STANDARDS

· A generic diagnostic system would require the specification of many off-the-shelf components. There are two potential approaches for diagnostics: on-board .devic.es and off-board devices. Further, off-board devices can be segmented into portable and console (stationary) devices.

4.2.1 On-Board Devices

Display Techniques. The preponderant application of on-board diagnostics is to store microcontroller fault codes and display the faults to the vehicle operator and/or maintenance technician on demand. The devices themselves are currently the specific controllers supplied by the manufacturer of the component such as .the engine, transmission, or ABS braking system. The occurrence of such faults is often indicated by the illumination of a "check engine" light or similar.indicator. The indication of the specific fault is generally decoded by a "flashing light" methodology.

There are various divergent applications for the use of dashboard-mounted warning lights. These include warning indicators with messages such as: "stop engine", "check engine", "service now", "service soon", and "check electronics". These indicators are generally off, being illuminated for a bulb check when the key is first turned to an on position. At the service garage, a

40


service technician is able to check the vehicle system status by invoking a diagnosis mode and counting the number of pulses or illuminations of a dedicated warning indicator.

More recently, a number of vehicle manufacturers have introduced generalized displays that are capable of displaying diagnostic information. These devices, especially in connection with the data link, are able to display a range of diagnostic codes. Such displays include single character displays (generally based on seven-segment numeric display technology of liquid crystal display (LCD) or vacuum fluorescent (VF) display technology, multiple character displays based on sevensegment technology, or bit-mapped displays will all display points addressable as on a computer terminal.

Because of the rapid introduction of sophisticated electronics, "flashing light" technology is believed to only have a limited future. Future on-board diagnosis will be based more on the realtime logging of vehicle faults and system condition "snapshots" together with more sophisticated displays of the diagnostic information. It is probable that the display of this information will be in connection with an off-board diagnostic device.

Real-Time Fault Logging. The current state-of-the-art will allow for the real-time capture and storage of diagnostic information on the vehicle to be later down-loaded and analyzed by offboard diagnostic equipment. This function should be added to all on-board controllers on the vehicle. It should be a permanent feature of the vehicle.

At· the lowest level of complexity, each ECU will simply record the fault or malfunction codes that occur while the heavy truck vehicle is in operation. The fact that the fault occurred may or may not be indicated to the driver by the warning light indicator depending on the fault severity. These codes would be brought to the attention of the service technician when a diagnostic tool is next attached to the data link.

On-board diagnostic logging should permit the manufacturer, or alternatively fleet management, to define what and when data is to be recorded on the vehicle. The manufacturer/owner should be able to specify trigger events or faults and an associated list of parameters to be recorded with the fault such as engine speed and vehicle speed.

An adequate diagnostic system must permit dynamic specification of fault codes and related data parameters. This activity should be addressed by industry standardization activities.

4.2.3 Off-Board Devices

Because of the diversity of manufacturers, technician preferences, and supplier strategies in the off-board diagnostic device category, it is virtually impossible to rigidly define the operation of a diagnostic device. However,· it is possible to emphasize the functionality that such devices should have in the interest of industry standardization.

Portable Diagnostic Devices. This type of device should be portable with a keyboard and it should be no larger than a typical laptop computer. It should have an environmentally protected

41


keyboard and an alphanumeric character display. It should be water and shock resistant. It should support the J1708/J1587 data link protocols and it should have a connector and cable for attachment to the vehicle data link. It should be capable of obtaining power from the vehicle by bus connection. It should display the current data on any ECU requested by the inspector or. technician.

The portable device should support erasure of stored fault codes, test switch status, and display all parameters to which the manufacturer or fleet management has not limited access. It should be capable of storing all of the diagnostic data obtained from the vehicle for communication to a full-range diagnostic device. It should support communication with a station or console-based device for full-range diagnosis.

Stationary or Console-Based Devices. This type of device should have at least an 80 column by 40 line information display. It should also support bit-mapped graphic displays. This device should preferably· be based on generalized software standards such as MS-DOS or Windows. The device should be user-friendly, based on icons and menus. Like the portable device above, it should support the J1708/J1587 data link protocols and it should also communicate with the portable device. Communication linkage can run the gamut from a standard RS-232C port to communication via infrared LAN or similar technologies with the hand-held portable device.

4.2.4 Diagnostic Device Connections

One of the most essential elements for the widespread usage of a standardized diagnosis capability for the heavy commercial truck industry is the definition of an off-board diagnostic connector. Such a connector has to be usable by all devices requiring access to the serial data link in a standardized and readily accessible location.

Current Connectors in the Heavy Truck Industry. The industry has cooperated to develop hardware and software standards for communications among electronic devices on the heavy truck including diagnostic information. Further, the industry has recently developed a standard diagnostic connector configuration to eliminate the fragmentation that existed on trucks with electronic diagnostics in years past. The variety of connectors that· existed prior to adoption of the standard connector is shown in table 6. In addition to OEM' s included in the table, Ford and Volvo/GM used the connector provided by the engine manufacturer. This was prior to the SAE/TMC Recommended Practice (RP) 1202.

It is anticipated that by 1994, all of the manufacturers and suppliers will have converted to a standard diagnostic connector for the J 1708 data link. The connector is the specification met by the HD-10 six-pin connector manufactured by Deutsch. It is important to note that two of its six pins remain available for vehicle- and engine-specific purposes.

Location of the Connector. The standard data link connector is generally mounted in the cab. However, the location is not standard. Table 7 illustrates the variety of locations that the current heavy truck design population supports. It can be seen that many of these locations require either tilting the hood or the cab on cab-over engines (COB's) of the vehicle. Even in-cab locations often require climbing up and entering the cab in order to attach the diagnostic connector. In

42


Table 6. Heavy-Duty Diagnostic Connectors Before Standardization

OEM Vehicle Manufacturer

Component Supplier F reightliner Mack Navistar Peterbilt Western International Ken worth Star

Allison ATEC 12-pin GM Connector

Allison World 12-pin GM Connector

Cat 3176 9-pin Deutsch 6-pin Deutsch 8-pin Navistar 9-pin Deutsch 9-pin Deutsch Connector Connector Connector Connector Connector

Cat 3406 9-pin Deutsch 6-pin Deutsch 8-pin Navistar 9-pin Deutsch 9-pin Deutsch Connector Connector Connector Connector Connector

Cummins PACE 2-pin AMP 2-pin AMP or 8- 2-pin AMP Connector pin Navistar Connector

Connectors

Cummins PT 2-pin AMP 2-pin AMP or 8- 2-pin AMP PACER Connector pin Navistar Connector

Connectors

Cummins CELECT 2-pin AMP 2-pin AMP or 8- 2-pin AMP 2-pin AMP Connector pin N avistar Connector Connector

Connectors

Detroit Diesel 12-pin GM 6-pin Deutsch 8-pin Navistar 12-pin GM 12-pin GM DDEC 1111 Connector Connector Connector Connector Connector

Mack V-MAC 6-pin Deutsch Connector

Rockwell 6-pin Deutsch WABCO/ABS Connector

addition to OEM's included in the table, Ford and Volvo/GM generally utilized the connector provided by the (engine) manufacturer on the side of the engine until standardization was defined by RP 1202. The Volvo/GM exception to this was when the Detroit Diesel engine was used. Where it was used, they located· their connector in the ·electrical center near the center of the dash.

Currently, diagnostic tools are viewed as an aid to be used in the repair activities of the maintenance shop. In the future, these will become more widely used in preventive maintenance activities. Further, the use of diagnostic tools by vehicle inspectors in a roadside environment to assess the functionality and efficiency of emissions and safety systems is a very real possibility.

43


Table 7. Heavy-Duty Diagnostic Connector Location

OEM Vehicle Manufacturer

Component Supplier F reightliner Mack Navistar Peterbilt Western International Ken worth Star

Allison A TEC In cab on left kick panel

Allison World In cab on left kick panel

Cat 3176 On engine left In cab under In cab on kick On engine left On Engine left side dash panel side side

Engine on left side

Cat 3406 On engine left In cab under In cab on kick On engine left On engine left side dash panel side side

Engine on left side

Cummins PACE In cab on left In cab on kick On engine ECU kick panel panel or dash/

On engine ECU

Cummins··PT In cab on left In cab on kick On engine ECU PACER kick panel panel or dash/

On engine ECU

Cummins CELECT In cab on left In cab on kick In cab under On engine ECU kick panel panel or dash/ dash

On engine ECU

Detroit Diesel In cab on left In cab under In cab on kick In cab under In cab under DDEC 1/II kick panel dash panel or under dash dash

dash

Mack V.-MAC In cab under dash

Rockwell In cab on left WABCO/ABS kick panel

This would require· connecting the diagnostic tool, not just when the vehicle is in the shop with a problem, but each time it enters the fleet yard or shop and each time it enters an inspection station.

For a roadside inspection, ideally, the inspector must be able to reach the connector while standing on the ground without entering the vehicle. This would virtually mandate a left kick panel location. The same location would be desirable for a routine attachment and review of the engine,

44


transmission, and· other system ECU information as part of a preventive maintenance program on predominantly electronically controlled units.

Further, guaranteed environmental protection will be difficult to· obtain if the connector is externally mounted and protected by a cap. Alternatively, passive environmental protection of the connector would be cost prohibitive to obtain on the heavy vehicle. Thus, a relatively benign environment in the cab would be the optimal solution.

It is suggested that a dedicated diagnostic connector location be designated in order to support off-board diagnosis. It probably should be located inside the heavy truck cab near the driver's door. The connector should be located low enough as to be accessible without the inspector or maintenance technician having to enter the vehicle--probably on or near the left kick panel.

4.3 DIAGNOSTIC DEVICE OPERATOR INTERFACES

A standard practice should be defined for diagnostic devices that dictates a standard display and query methodology for the interaction with the diagnostic device. The inspector or service technician will then become familiar with the interface and will be productive as he/she moves among various diagnostic tools. This may be difficult inasmuch as there are various levels of sophistication and information. Each level will have different costs. A standard display and query methodology should provide clear messages, minimize training, and simplify data presentation.

Due to the sophistication of systems using diagnostics, it is anticipated that "flashing light" techniques will soon be inadequate. As the nee4 for interaction increases and the number of different codes increases, these techniques must of necessity be replaced by more efficient systems. Therefore, ·this will not continue to be a viable means of communicating diagnostic code.

On-board displays would have three potential audiences. These are the driver at the time of fault occurrence, the service technician after the fact, and the manufacturers' authorized service technician at a dealer or distributor. The on-board display should be capable of immediately alerting and notifying the driver to stop if necessary. It should also display the fault condition code if the driver needs to communicate it to his/her dispatcher. Secondly, the service technician should have access to all fault data including component identification and parameter values. Lastly, authorized service personnel should be able to use the display to access all fault conditions, vehicle environment, and operating details.

Off-board displays should display fault codes, sensor values, switch positions, and any other parametric data required to solve the vehicle malfunction problem. This should be all of the data available to the ECU of any component that is meaningful to the fault isolation process.

The off-board display should provide clear messages, minimize training, simplify the data request, and simplify the data presentation. It probably should provide a help screen display that is easily accessible with a single key. Perhaps a standard based on aDOS-Windows environment would be the most practical long-term standard for the heavy duty industry.

45


4.4 TECHNICAL FORECAST OF "TOMORROW'S TRUCK"

It is expected that the commercial vehicle industry OEM's who function as the "system integrators" will each continue to follow one of the three basic strategies that they have all followed to date:

A. One concept has been to "push the limits of technology" and strive to reach the ultimate goal of completely proprietary and integrated vehicle systems. The result has been comprehensive and integrated functional controllers, developed as proprietary units by the OEM.

B. A second concept has been to take a passive approach to the development of electronics technology, especially that related to unique vehicle level control functions. Under this alternative, OEM' s will generally monitor, evaluate, and integrate state-of-the-art industry supplied electronics components when available with little or no proprietary electronics function development. This would be in a traditional role as a "merchant assembler" of supplier componentry. This method has generally resulted in a relatively loose confederation of separate electronic-based systems on the vehicle, often with redundant sensors, pickups, and output displays and instruments despite the opportunities for data sharing using the SAEdefined J1708/J1587 data bus.

C. A third alternative has been to steer a middle course between the other two extremes. In this role, the manufacturers have focused on functions of strategic design importance such as vehicle wide controls and monitoring.

It is believed that the supplier structure within the industry will not be significantly changed during the 1990's from that existing today. All of the heavy commercial vehicle manufacturers will have access to the same engine control, anti-lock, and recorder products as well as common electrical connectors, alternators, batteries, starters, and lighting components. Thus, many of the on-board electronic system features of vehicle competitors will be generic and little differentiated from each other. However, at the level of display instrumentation and certain vehicle control functions, there will still be significant technical product differentiation.

The component suppliers thems~lves are expected· to aggressively utilize microelectronicbased controllers in order to provide advanced features that give them operational, cost, or similar competitive advantages. It is conceivable that the heavy- duty Class 8 truck of the year 2000 could be equipped with as many as 50 electronic systems. More likely, there will be between three and seven "intelligently" controlled electronic devices. These will include the following: engine, transmission, brakes, retarder, the instrument cluster, trip recorder, and an off-board communications device. Some sort of network would be required to permit these electronically controlled devices to share information. The benefits of this networked sharing of information includes: elimination of redundant sensors, simplified wiring, coordinated driveline components (engine, transmission, and brakes) to improve safety and efficiency, and ,single-point data. collection for diagnostics. Other devices that may. need to be linked into the network include proximity sensor devices, tire pressure monitoring, and vehicle security devices.

46


Figure 3 illustrates a schematic for tying together a number of intelligent electronic devices on a heavy truck using a data bus or wiring linkage to form a network. This data bus is a wire or set of wires used to transmit information between the devices. It is expected that the networking of these devices will increase and be a standard feature of tomorrow's truck. Table 8 indicates the expected introduction date for various electronically-based applications on the heavy duty truck of tomorrow.

47

OFF-BOARD DIAGNOSTIC DBVICE(S) • GBNBR.IC •PROPRIETARY

SENSORS

MISCELLANEOUS BUSINBSS CONTROLLED SYSTBM(S)

TRANSMISSION

ON-BOARD SAB STANDARD DATA LINK (BUS)

VEJHCLB BUSINBSS SYSTEM (RBCORDBR)

VEIHCLB COMMUNICATIONS SYSTEM

Figure 1. Schematic of Networking Devices

INSTRUMENTATION/ DRIVER INTBRPACES - PROPRDU'ARY BCU'S


Table 2. Forecast of Heavy Duty Truck Electronics

Application

Engine Speed Controls Engine Protection Electronic Engine Controls Transmission Controls Vehicle Speed Controls Automated Engine Cooling Axle Controls Automated Traction Control Anti-Lock Braking Tire Pressure Monitor Brake By Wire Electronically Controlled Steering Steer By Wire Adaptive Suspensions Automatic Weighting Axle Load Sensing Cargo Monitoring Aerodynamic Surface Controls PTO Controls Electronic Driven Discreet Gauges Full Digital Displays Vehicle History Recorders Trip Data Recorders Crash Recorders Service Advisory Records High Speed Data Link Multiplexed Electrical System Cab Environment (HVAC Controls) Seat Controls Lighting Controls Mirror Controls Blind Spot Detection Rear Obstacle Detection Security--Anti-Theft Anti-Theft Remote Keyless Entry Communication System

Introduction Date

1987 1987 1989 1988 1987 1994 1991 1990 1987 1990 1996 1992 1997 1994 1992 1989 1990 1995 1987 1988 1988 1990 1987 1991 1991 1994 1996 1988 1989 1989 1989 1991 1995 1989 1995 1990

49

50% Penetration Point or Full Production

1993 1993 1994 1996 1993 1997 1998 1996 1995 1998 2000+ 1998 2000+ 1998 1999 1999 1997 2000+ 1995 1995 1998 1997 1997 1997 1997 1999 2000+ 1993 1996 1997 1996 1997 2000+ 1996 2000+ 1998


Table 2. Forecast of Heavy Duty Truck Electronics (continued)

Application Introduction

Date

Security--Relocate Stolen Vehicle Automated Load Advisory Navigation CRT with Maps Precise Location Driver Performance Impairment Monitors

--Chemical

1991 1991 1997 1991 1995

Driver Performance Impairment Monitors 1995 --Fatigue

50

50% Penetration Point or Full Production

1997 1998 2000+ 1998 2000+

2000+

Chapter 5: Recommendations

CHAPTERS

RECO:MMENDATIONS

It is recommended that each manufacturer continue to log its own diagnostic fault data in its own ECU. Further, this should be augmented with additional data so that a "snapshot" of the vehicle system condition is taken at the time of the fault being detected. Industry standardization would then focus on standardized techniques for extracting ~d displaying the logged data to inspectors in a roadside environment and to the vehicle service technicians in the repair garage.

5.1 POTENTIAL FOR OTHER SENSORS

Further, there are additional applications that could be used for on-board performance analysis of the vehicle's safe operation and legal emissions. Potential parameters to be measured by on-board vehicle diagnosis are shown in table 6. Going beyond the strictly mechanical elements of roadside inspections, consideration should also be given to other elements that are conducive to electronic monitoring and readout. On-board systems could include driver logs and other paperwork, vehicular weights, wheelbase (for Bridge Formula compliance), and hazardous materials information.

Some elements in table 6 pertain to safety issues while others relate to emissions. Contacts with Office of Motor Carriers personnel who inspect vehicles and/ or train others to inspect vehicles resulted in a number of parameters that should be considered. These are important either because they are physically difficult to measure or current methods of measurement/observation yield less than consistent results. Current measurements of safety parameters require the inspector to crawl underneath the vehicle to measure, feel, and/or listen for problems. Given the increasing widespread use of aerodynamic fairings in the Class 8 truck population, crawling underneath the tractor has become a problem.

In some of the table 9 parameters, there exists the need to monitor multiple variables and record them for later retrieval. For example, to accurately monitor brake function, prevailing conditions must be known. A desirable list includes initial and final vehicle speed, whether the vehicle is loaded or unloaded, air pressure applied at the brake, heat generated by each brake, and brake torque.

5.2 SAE/TMC STANDARDIZATION EFFORTS

It is recommended that free-market heavy truck standardization efforts be continued through the SAE and TMC activities. The efforts have resulted in and will continue to develop standard data links, data protocols, a standard diagnostic connector, and a common connector location.

51


Regulatory Impact

Emissions

Safety

Table 9. Potential Additional Parameters to be Measured on Heavy Trucks

Parameter/ Application Comments

On-board real-time Modification of Stedman on-road emissions device for measurement of CO diesel engines

Particulates On-board opacity measurements of normal conditions of particulate matter

Check of various engine Integrity of engine parameters to detect faults that parameters impact emissions

Brake function Brake drum temperature differences between wheels

Air pressure leak down

Air pressure drop upon brake application

Brake adjustment Push rod stroke

Brake shoe travel

Axles/weight/ suspension Weight sensors for overweight or unbalanced load

Spring deflection detector

Excessive mechanical wear Excess steering system wear or cracks

Frame deflection sensors

Axle shift detector

Broken/loose wheel

Tire inflation pressure Tire pressure sensors

Heat sensors (to detect flat tires)

Sliding fifth wheel Latch detector

Position detector

Sliding trailer tandem Lock detector

Position detector

52


Comparison of the on-board diagnostic systems for anti-lock brake systems for Eaton, Midland-Grau and W ABCO indicates that non-standardized fault information is produced for maintenance and inspection personnel. Only vague similarities exist within code groupings. With NHTSA' s recent Notice of Proposed Rulemaking on ABS, this disparity becomes more critical. It would appear that SAE/TMC efforts should address this need for standardization.

5.3 DIAGNOSTICS FOR ROADSIDE INSPECTIONS

The Government should remain a facilitator in the process of accomplishing standardization to ensure that the roadside inspection needs are met, in addition to the needs of motor carrier maintenance personnel. This might result in a minimal set of public data standards and hardware necessary to comply with governmental needs. However, because of the sensitivity expressed by motor carriers to allowing access to the complete set of diagnostic codes on the vehicle, component and vehicle manufacturers should be encouraged to secure those parameters not needed for safety and emissions inspections. The resulting open system for roadside inspection would be less powerful than existing systems, using only a limited subset of parameters. Having a less powerful system for roadside inspections might result in more on-board complexity resulting in added cost to be borne by the industry.

The preferred method of achieving a standard off-board tool for roadside inspection would involve making use of ongoing industry standardization activities and using the potential large market volumes to obtain a low cost hand-held or console-based diagnostic tool. Even though this ongoing industry standardization will probably take three to five years, it avoids the need for government involvement. This time lag will actually not be a detriment to electronic diagnosis anyway, given that some systems on the vehicle today will not be significantly conducive to adding diagnostics until perhaps the tum of the century. It is anticipated that, by that time, several on-board safety systems will not only have the capacity for electronic diagnosis but that the number of these systems will be sufficient to cause a significant impact on the roadside inspection process. As an example, if electronic diagnosis were only available to one minor system on the vehicle, reducing current average inspection. times from 30 minutes to 28 minutes, there would be too little incentive for either the industry or inspection personnel to invest in the change. However, if at some future date, average inspection times could be reduced from 30 minutes to 15 minutes due to several new electronic systems with supporting on-board diagnostics, it is expected that the incentives would be sufficient to encourage and achieve participation.

A standard diagnostic tool should be based on an open hardw~e and software platform in order to minimize the development costs and eliminate any supplier advantages in winning such a "prize." The most optimal platform would be based on the "IBM PC" standard. These computers are widespread, amounting to over 91 percent of the personal computer base. They have a widespread common hardware foundation based on the Intel family of microprocessors. Further, there is a generic set of software standards based on MS-DOS and WINDOWS. It is recommended that the platform be WINDOWS based because it provides an open graphic standard as well as offering ease of use.

53


5.4 FUTURE TASKS

There are some additional applications that should be examined for their practicality for on-board performance analysis related to the vehicle's safety status and emissions levels. Several ideas were provided in table 6 suggesting that various sensors might be added to emissions and safety systems on the vehicle to provide more comprehensive and more consistent information during a roadside inspection. It is recommended that Task A-2 be changed from conducting a cost-benefit study of standardization to investigating the feasibility of new sensor systems for use on Class 8 vehicles. Each sensor set evaluation would include a cost estimate, estimated cost-benefit, feasibility of implementation within the next 5 to 10 years, its effect on roadside inspections, and potential impacts on accident reduction.

Task A-3 involves determining what, if any, cost-sharing opportunities are available from non-federal entities for development of standardized diagnostic tools. At this time, based on the limited interviews conducted to date, these opportunities are ·expected to be limited. However, without conducting a more structured process with an appropriate experimental design and statistical analysis, it is not possible to provide definitive conclusions regarding the potential of cost-sharing activities. The recommendation is to go ahead with this task to gather a sufficient number of responses to determine what opportunities exist.

54

Section 8.0 References

REFERENCES

1. Hames, Richard J., Hart, David L., Gillham, Gregory V., Weisman, Steve M., and Peitsch, Bernd E., "DDEC II- Advanced Electronic Diesel Control", SAE 861049, Detroit Diesel Allison Division, General Motors Corporation, 1986.

2. Spivack, H.M., Differential Transducer for Vehicle Diagnostics, U.S. Army TankAutomotive Command, Research, Development and Engineering Center, Warren, Michigan 48397-5000, Contract Number DAAE07-86-C-R088, Febru~ 1990.

3. Holmelius, Hal, "Scania CAG- Computer-Aided Gear Shifting," SAE 861051, SaabScania AB, Sweden, 1986.

4. Bender, J.G. and Struthers, K.D., "Advanced Controls for Heavy Duty Transmission Applications", SAE 901157, Allison Transmission Division, General Motors Corporation, 1990.

5. Lukich, Janice M. and Brandt, Wayne D., "Integrated Diagnostics for the Vehicle System," SAE 912683, Caterpillar, Inc., Peoria, IL, 1991.

6. Foy, Lucinda A., "Real-Time Processing Applications for Heavy-Duty Trucks," SAE 861066, Charlotte Technical Center, Freightliner Corporation, 1986.

7. Malecki, Richard L. and Snyder, Charles R., "Diesel Electronic Engine Controls in the North American Heavy Duty Truck Market," SAE 861077, Navistar International Corporation, 1986.

8. Bishel, Richard A., "Standardized Truck Diagnostics - The Road to Progress," SAE 891680, PACCAR Technical Center, PACCAR Inc., 1989.

9. Stepper, Mark R., "Data Link Overview for Heavy Duty Vehicle Applications," SAE 902215, Cummins Electronics Company, Inc., Columbus, Ohio, 1990.

10. "Summary of State Diesel Emissions Inspection Programs," American Trucking Associations, Inc., Department of Environmental Affairs, Alexandria, Virginia, April 1993. '

11. Code of Federal Regulations, Part 49, Subpart 393, U.S. Department of Transportation 1993.

55

APPENDIX A

Annotated Bibliography

Appendix A

Austin, J. William and Weimer, Robert J., " Service and Support of Electronic Products in the Trucking Industry," SAE 871579, Cummins Electronics Company, Inc., Cummins Engine Company, Inc., 1987.

Austin and Weimer found that the introduction of electronics to the trucking industry can be characterized by the following two "people problems": lack of electrical experience and a "parts-changing" orientation. The effects of this technology on a heavily mechanical industry are very pronounced in the service and support areas. These problems are a result of issues generic to the trucking industry as well as ones which are specific to either the diesel engine or vehicle electronics businesses.

The heavy duty truck is a product that is jointly developed from integrated products that are produced by multiple manufacturers. This makes individual product design efforts more difficult and significantly impacts the product support efforts due to the differing designs and, therefore, differing support tools, manuaJs, and procedures. The various component manufacturers and original equipment manufacturers have been impacted to varying degrees due to the differing amounts of electronic content in their present and proposed future products.

Recent legislation regarding emissions has resulted in the need for electronic controls on the diesel engine, which has not had any electronic content to date. Experience with electronics in military, automotive, and other industries all point to a high incidence of "No Trouble Found" (NTF) failures. NTF failures are defined as components which have been removed from operation (in this case removed from the truck) and are returned to the warranty, repair or service center. Upon reinspection, these components are found to meet all functional tests. While these effects may occasionally be the result of inadequate tests, the number of NTF failures is commonly a measure of the adequacy of service tools and diagnostic procedures.

Efforts to resolve vehicle integration problems have centered around standardizing interfaces. This was undertaken to eliminate confusion over how the various products are intended to interact with each other. The standardization process is well understood as evidenced by the degree to which there are standards for components such as tire and rim sizes and engine to transmission bolt patterns. This same process applies to electrical interfaces. The major interface between truck electronic products is a communication link, as defined by an industry SAE standard.

The approach taken by the authors to solve the diagnostics dilemma is to stress consistency --familiar test methods, standardized tools, and thorough training aids that are flexible and upgradeable. The service tool strategy which was developed for this philosophy calls for a tiered approach. There are four tiers which allow for service at various degrees of investment, ranging from on-board diagnostics that come as standard equipment with the product, to optional tools such as E-CHEK, Compulink, and Compuchek. Each successive plateau allows. incremental enhancements in productivity and there are tools that satisfy service needs for the full range of products and service personnel.

59

Appendix A

The first level of tools consists of internal or on-board control modules. The basic operational steps of the control modules are as follows: 1) faults cause codes to be stored in the control module; 2) fault indicators in the instrument cluster illuminate while the fault is active; and finally 3) the exact fault can be determined by either turning on the test switch in the cab, interpreting the code number from flashing lights, or isolating the fault with the fault tree in the service manual

The second level of tools consist of the E-CHEK service tool, which is the lowest level off-board tool. It presents service personnel with a device which is: small enough to go anywhere, handheld, and inexpensive. This tool allows service personnel to easily obtain information stored in the control module, wherever the control module is located on the vehicle. E-CHEK interprets the information and presents it in engineering units such as RPM and degrees Fahrenheit. The device also reads fault code numbers and sensor values, and allows service personnel to isolate a fault with the code, sensor values, and service manual.

The key tool developed to provide both diagnostic and calibration functions is Compulink. Its functional capabilities include: read and display stored fault codes, read data associated with faults, use self-contained fault trees, use codes and symptoms to work down the fault tree, perform special tests (such as cylinder cut outs), and perform simple adjustments. It can be attached to a PC network, adding full calibration capability. Compulink is portable, flexible, and durable.

The fourth level tool is a version of the service bay computer that is currently used in maintenance shops today. This tool represents computational capability brought into the service bay and current state-of-the-art engine analysis features. The fourth level tool must have additional electronic analysis capabilities which can 1) do all functions of the three lower level tools, 2) analyze electronic engine controls--as well as "mechanical" components, and 3) analyze other electronics on vehicles.

60

Appendix A

Bara, Mark F., Hames, Richard J ., and Henriksen, Craig 0., "Field Experience with the Detroit Diesel ~Iectronic Control System," SAE 901159, 1990.

The introduction of the Detroit Diesel Electronic Control system (DDEC) in 1985, precipitated a tremendous learning curve in the application of electronics to the heavy-duty truck market for both the engine manufacturer and the vehicle builder. The application of electronics to heavy-duty diesel engines was motivated by the basic needs of competitive fuel economy and performance at legislated reduced exhaust emission levels. Electronic control of the direct injection unit injectors common to Detroit Diesel products was envisioned as the optimum in the control of injection timing and metering events. The flexibility offered by programmability would provide the basic tool to develop low emission engines with excellent performance and fuel economy. Having reached a decision on applying electronics to achieve these primary objectives, the flexibility of electronics was utilized to maximize customer benefits such as improved cold startability, engine protection and system diagnostics, idle shutdown, road speed limiting, and cruise control.

A formal reliability engineering program was completed to insure that the reliability goals, representing stringent customer expectations, could be demonstrated. Serviceability was addressed throughout the specification and design stages. This included eliminating the need of service adjustment for injection timing, cylinder-to-cylinder fuel balancing, governor speed adjustments, and the incorporation of system self-diagnostics. Unique diagnostic features were developed based on field experience with the mechanical unit injection system. Diagnostic test equipment and troubleshooting procedures were developed and evaluated as part of the .reliability test program. Engine protection diagnostics for the oil and coolant systems were added to. prevent catastrophic failures.

The DDEC system is self-diagnostic and identifies malfunctions through the illumination of a Check Engine Light (CEL) and Stop Engine Light (SEL). The seriousness of the fault is indicated by which light or lights are illuminated. An amber CEL usually indicates a fault with a sensor or wiring. Illumination of the CEL and red SEL indicates an out of limit fault condition for low oil pressure, low coolant level, or high engine temperature. Codes are stored in memory to identify the fault. The two methods to read the fault are: by obtaining the codes by using the diagnostic request switch typically located on the dash and· interpreting the code using a pocket card, or by using a handheld Diagnostic Data Reader (DDR) that plugs into a connector typically located under the dash.

The DDR can also be used to perform tests on the engine, aiding in the evaluation of mechanical problems. The system self-diagnostics detect the presence of a fault and logs codes that isolate the fault to a particular subsystem. The troubleshooting guide fault trees lead the mechanic step-by-step through fault isolation, repair, and confirmation tests. The primary shop floor tools for servicing the DDEC system are the DDR and a digital multimeter. The DDR can read fleet-type information stored in the ECM's memory such as total engine hours, idle hours, and total fuel consumed. Simple tripmeter information is also available, such as trip miles, trip fuel (gallons), and trip average fuel (MPG).

61

Appendix A

Bender, J.G. and Struthers, K.D., "Advanced Controls for Heavy,·Duty~Tradlmission Applications," SAE 901157, A~on Transmission Division, General Motors Corporation, 1990. ·

Allison Transmission Division of General Motors Corporation is currently developing an electronically controlled automatic transmission system utilizing advanced technologies in microprocessors, application specific integrated circuits (ASICs), sensors, actuators, displays, and direct electronic clutch pressure control. The transmission system has been designated as the World Transmission (WT). Included is a complete family of heavy duty automatic transmissions which will become part of the Allison Transmission product beginning in 1991. The WT ·design provides expanded capabilities over present transmission technology and results in improved performance with benefits in life cycle cost. The microprocessor used in the WT transmission is a second generation Allison Transmission Electronic Control system (ATEC II).

A major aspect of the ATEC Il system is the integration of the electronic control circuitry with a push button shift selector unit. This integrated unit contains the input/output electronics and the microcomputer. The control unit is based on state-of-the-art technology, which includes surface mounted chip resistors and capacitors and multi-layer circuit board construction, to achieve a highly reliable, inexpensive, .compact design. The microcomputer selected for the A TEC II system is the Motorola MC 68HC 11, which is a powerful, highly integrated CMOS device particularly suited for automotive electronic controls. Three types of memory are employed in the ATEC II electronic control unit (ECU) including RAM, EEPROM, and a one time programmable PROM. The microcomputer used in the ECU assembly supports two different external serial communication link interfaces: a Remote Serial Interface (RSI) and the Serial Communications Interface (SCI).

The RSI links the electronic control unit to up to two remote shift selectors. In general, the SCI performs two major functions. First, it provides data to a diagnostic data reader to facilitate servicing and/or system performance parameter monitoring. Second, the SCI can be used to receive throttle position information from an electronic engine control unit; in this case, the requirement for a separate ATEC II throttle sensor is eliminated.

The A TEC II subsystem and transmissi9n hardware are supported by9.compp!hensive built-in diagnostics and simple, but effective, maintenance tools. The ECU'!xamirls the condition of the transmission, status of the entire control system, and performs a periodic self-check. If a problem is detected and verified, a "SERVICE" transmission light is illuminated to signal the operator. The diagnostic information is stored in EEPROM in the for of descriptive codes that isolate the failure to individual components for future maintenance action. Provisions are made for both current and historic diagnostic codes. In general, the diagnostic code remains stored in memory even if the anomaly disappears. This feature is· critical in identifying intermittent problems which can occur in electrical systems. The diagnostic codes can be displayed on the integrated digital display or on a portable diagnostic tool.

62

Appendix A

As part of the initial ATEC II program, a standard portable diagnostic tool defined as the Diagnostic Data Reader (DDR) was developed to simplify the service function. This tool provides both a diagnostic and parametric digital readout device. It features an 8-line, 20 characters per line digital liquid crystal display (LCD) and 16 key pad. The keypad contains a menu key, select key, data key, up arrow key, down arrow key, English to metric key, and 10 keys each containing a number 0 to 9. Each key is "touch sensitive" for easy use. The display and keypad are illuminated for night operation. This very flexible menu driven DDR provides a common service tool for the Allison ATEC I and ATEC II systems and also for the Detroit Diesel Corporation DDEC I and DDEC II electronic engine control systems.

63

Appendix A

Bishel, Richard A., "Standardized Truck Diagnostics - The Road to Progress," SAE 891680, PACCAR Technical Center, PACCAR Inc., 1989.

Diagnostics have become an important factor in the trucking industry. The major reason for the growing influence of diagnostics is the increased complexity of electronically controlled engines. Other reasons that have contributed to the growing importance of diagnostics are the increased computational capability of on-board controllers, the 11708 standard truck communication link, the decreased cost of electronic components, and the increased reliability of electronics. As more electronic products are incorporated on vehicles, the complexity of troubleshooting increases and the use of supporting on-board and off-board diagnostic capabilities becomes more significant.

Electronic products such as engine controls are complicated to repair without diagnostics and the current suppliers and manufacturers haveincorporated varying levels of diagnostics. Blinking lights, fault code readers, and other means have been devised to display diagnostic information from engine controls. However, the capabilities of each diagnostic tool provided by the engine manufacturer are proprietary to that specific engine.

Diagnostics, like other electronic products, have their own problems and terminology which are often unfamiliar to service mechanics and technicians. In addition, mechanical components, especially in an environment like the truck industry with many different suppliers, cannot be easily categorized. For example the code which would indicate a fuel solenoid malfunction on a Caterpillar engine, would mean something different on a Cummins or Detroit Diesel engine.

In the 11708 and 11587 Recommended Practices, devices or systems on-board the vehicle were categorized and numbered. The message identification assignment (MID) indicates what number is associated with what system or device. For instance Number 128 indicates an engine, number 129 indicates a turbo-charger, and number 146 indicates ·a cab climate control system. Because these numbers were developed to indicate which device transmitted the sensor information, using them to indicate which device sent the fault information was a ·foregone conclusion.

11587 categorized parameter information of the data link. Parameter identifiers (PIDs) were assigned for different types of sensed information. As with the MIDs, it made sense to use these number assignments in diagnostic protocol. Since there are parameters and components that do not fall into the sensor category, another category was defined and listed for each device or system MID. This category was denoted as sub-system identifiers (SIDs). SIDs parameters are defined for a device for which failures can be detected and isolated by the device.

In the future, diagnostic equipment will focus on two areas: on-board and off-board tools. It is anticipated that this diagnostic equipment will use standardized fault codes. In order to avoid obsolesc~nce in standardized diagnostic equipment as new components are defined and the list of codes is updated, a method was adopted to allow

64

Appendix A

diagnostic equipment designed today to request fault code information from the new device. Electronic products designed in the future could contain a brief definition of the sub~system component. Thereby, when new electronic equipment is added to a vehicle , the on-board and off-board service tools could request this information. Without this feature, motor carriers would be forced to keep their diagnostic equipment current by software revisions and module changes. Another problem would be mechanics not knowing what a fault code means.

65

Appendix A

Gillespie, Thomas D. and Kostynuik, Lidia P., A Rationale for Establishin& the Period of Validity for CVSA Truck Inspection Decals, Michigan State Police, Office of Highway Safety Planning, 300 South Washington Square, Lansing, Michigan, April30, 1991.

Trucks that travel on highways are subject to several levels of inspections. The lowest and also the most common level of inspection is the driver or walk around inspection. This is a cursory inspection that is required to be performed prior to driving the vehicle. In the process of walking around the vehicle, the driver is expected to check designated items either by visual inspection or operation of the subsystem. Items that are inspected include: parking brakes, service brakes (to include trailer connections), steering mechanisms, lighting devices and reflectors, tires, horns, windshield wipers, rear vision mirrors, coupling devices, wheels and rims, and emergency equipment. The second type of inspection that every vehicle undergoes is the periodic preventative maintenance inspection. This type of inspection is conducted by a mechanic performing maintenance on the vehicle. However, there are no universal standards for the mechanic to use for inspections conducted during preventative maintenance. Therefore, the quality of this type of inspection varies, and is dependent upon the practices of individual fleets.

Effective July 1, 1990, Federal Motor Carrier Regulations required that every commercial motor vehicle undergo an annual inspection. Commercial vehicle inspections are conducted by State enforcement personnel under the Motor Carrier Safety Assistance Program (MCSAP) for the purpose of removing trucks from the road that have defects serious enough to affect their operation. The Commerc~al Vehicle Safety Alliance (CVSA) is an independent organization that uses common truck inspection standards and out-of-service criteria which were developed in cooperation with the United States Department of Transportation (USDOT). The annual commercial vehicle inspection, which must be conducted by a certified inspector, is similar to the CVSA inspection with the exception that the criteria for passing the inspection are more stringent and no defects are allowed.

The CVSA inspection involve~ careful scrutiny of the vehicle and the driver. Particular attention is focused on those components that are designated as safety critical. Safety critical items include: steering, brakes, lights, tires and wheels, fuel system, exhaust system, suspensions, frames, couplers, cargo securement, header boards, and rear end protection. If no defects are found, a CVSA decal is affixed to each component of the combination. If 0/S violations are found and the vehicle is declared out of service, no 0/S decal is affixed to the vehicle. If only minor defects are found in the critical systems, which do not render the vehicle out of service, the vehicle still does not receive a decal.

The objective of the CVSA inspection program is based on the premise that vehicle defects lead to accidents, then inspections conducted to remove defective vehicles from the road will reduce the number of accidents. Two recent sources of information, a National Transportation Safety Board (NTSB) investigation of truck brake system condition and an Ohio inspection program, appear to demonstrate the validity of this premise.

66

Appendix A

In the Ohio study 5.4% of the vehicles inspected had a valid CVSA decal and only 0.6% of these vehicles failed inspection. Thus, the failure rate for vehicles with a valid decal was 12%. By comparison, vehicles without a decal obtained a failure rate of 19 percent. The 1990 NTSB study showed a general trend of increasing frequency of out of service violations as the age of the decal increased.

A second perspective regarding the appropriate period for validity of the decal is gained when the probability of the failure of a component as a function of time is considered. A large national carrier provided detailed information on the maintenance program for

tractors, semitrailers, and dolly converters. Several significant observations resulted from these data. First, trailers and· dollies have lower overall maintenance needs when compared to tractors, apparently because of their reduced complexity. Nevertheless, based on 1989 Michigan inspection data, trailers were found in violation and placed out of service as often as tractors. This discrepancy is probably due to a less rigorous maintenance program for trailers in many fleets.

This study found that the two largest maintenance items were brakes and lights. Lights were rated by experts as a low severity item. On tractors and trailers they are a primary maintenance item; however, the maintenance of lights on dollies is required as a minimum. Lights were not a frequent source of violations in the 1989 inspection data, presumably because light defects are highly visible and are easier to detect by drivers during their walk -around inspections. Brakes, on the other hand, were identified as a high severity item with a strong likelihood of defects contributing to accidents. They· are a relatively high maintenance item on every vehicle and are the major source of violations in MCSAP inspections. Fleets may underestimate the average maintenance needed for brakes if automatic slack adjusters are used exclusively. If the vehicle is equipped with manual slack adjusters, it will typically receive several more maintenance checks each year for brake adjustment. purposes.

When maintenance incidents are used as surrogates for inspections, it was found that the probability of failure grows with time. Typically, the probability of failure approaches unity at approximately three months from the date of repair. The authors, therefore, recommended continuing the three month validity for the CVSA decal.

67

Appendix A

Hames, Richard J., Hart, David L., Gillham, Gregory V., Weisman, Steve M., and Peitsch, Bernd E., "DDEC ll- Advanced Electronic Diesel Control", SAE 861049, Detroit Diesel Allison Division, General Motors Corporation, 1986.

DDEC II (Detroit Diesel Electronic Control) is an advanced technology electronic fuel injection and control system for diesel engines. Detroit Diesel Allison· introduced the Detroit Diesel Electronic Control (DDEC) in September 1985, and became the first U.S. engine manufacturer to provide an electronic engine control system for the heavy duty diesel trucking industry. This system, based on the General Motors Custom Microprocessor chip set, controls the fuel injection timing and quantity via electronic unit injectors. This two-box system includes a cab~mounted module containing the digital electronics and an enginemounted, fuel-cooled module with the analog injector driver components. Sensors, monitoring critical engine operating parameters, provide signals to DDEC for the microprocessor calculations. In addition to electronic fuel control and speed governing, DDEC I provided self diagnostics, engine protection diagnostics, and a wide selection of application options, such as cruise control and road speed governing.

The DDEC II development took advantage of advances in technology to integrate all control system electronics into a single engine-mount~, fuel-cooled electronic control module. Utilizing the General Motors Single Chip Microprocessor, it provides enhanced control system performance and additional control features as well as simplified OEM installation.

The major subsystems of DDEC II include the electronic unit injectors, the electronic control module, and the sensors. Fuel is delivered to the cylinders by the electronic unit injectors which are cam-driven for mechanical pressurization of the fuel and controlled via solenoid-operated. valves for precise fuel delivery. The electronic control module computes fuel timing and quantity and actuates the electronic unit injector solenoids through high current, pulse width modulated electronic drivers. The electronic control module ~so monitors the solenoid current to sense when the injector valve closes and uses this information to compute timing for subsequent injection events .

. The on-board diagnostics that were introduced with the DDEC I have been expanded and refined in DDEC II. These capabilities can be categorized into three areas: self diagnostics, engine system protection, and engine performance diagnostics.

The electronic control module continuously performs self-checks and monitors the other system components, including the injector solenoids, sensors and wiring. System diagnostic checks are made at ignition-on and continue throughout the time the engine is operating. ·Portable diagnostic equipment facilitates and expands DDEC II's diagnostic capabilities. The Diagnostic Data Reader requests and receives engine parametric data and fault codes via a serial communication link.

In addition to monitoring system components, the electronic control module also compares the sensor outputs against calibration high and low limits for the current engine

68

Appendix A

operating speed. The engine protection diagnostic for loss of oil pressure, oil overtemperature, and low coolant level can prevent a minor problem from becoming a major failure.

The portable diagnostics readers also provide a method of diagnosing engine performance problems not directly related to faults in the DDEC system. The DDEC system has eliminated many of the mechanical problems, such as mechanical adjustments to timing, governor linkages, govef~?.or spring settings, and foot pedal to engine linkages.

69

Appendix A

Holmelius, Hal, "Scania CAG - Computer-Aided Gearshifting," SAE 861051, SaabScania AB, Sweden, 1986.

Electronic systems have opened new· opportunities for automating vehicle gearboxes, either partially or entirely. A very high. degree of automation can be achieved providing opportunities for controlling and coordinating the gearbox with the engine and other vehicle functions. Scania has chosen to automate the preselection of gears.

The exact time at which the gear is engaged is left to the driver's discretion. The driver can use a small preselector lever, which is within easy reach, to override the computer and select a gear other than that the computer would engage. The automatically or manually preselected gear is actually engaged when the driver depresses the clutch.

The equipment for computerizing the gearshifting is designed for mounting directly on the existing five-speed and ten-speed Scania manual gearboxes. The microprocessor selected for the computer-aided gearshifting (CAG) system also provides opportunities for service benefits.

A switch is provided on the control unit of the computer for engaging a check and fault-tracing progratrt. This comprises testing of LEDs, buzzer signals, controls and switches, and the gearshifting movements for the main gearbox and planetary gearbox. Digital codes displayed in the gear indicator provide information on the location of faults.

The memory capacity of the microprocessor is also utilized for recording and storing disturbances that may occur in the system while the. truck is traveling. The. gear indicator is also used for displaying codes to show the faults that have been recorded.

Utilization of sensor input data and the computer has potential for further development. One enhancement would involve supplying the computer with more accurate, instantaneous information on engine torque. Using the input data from sensors and information concerning ·the gearbox, rear axle ratio, and tires, the computer could suggest gears that are better matched to the situation. ·

Iri the future the CAG system may be integrated with other electronic control systems. This may include control of engine and power train functions, programs for more disciplined driving, and various forms of safety systems. The need for standardization is growing in the current development of electronic control systems. Therefore, future development should seek ways to reduce the number of signal paths.

70

Appendix A

Lukich, Janice M. and Brandt, Wayne D., "Integrated Diagnostics for the Vehicle System," SAE 912683, Caterpillar, Inc., Peoria, IL, 1991.

Electronics on heavy-duty on-highway vehicles have enabled new and enhanced functionality and performance of the total vehicle. Vehicles are available with electronically controlled engines, transmissions, dashboards, braking systems, and other electronic components. While the number and complexity of electronic components on the vehicle continues to increase, it would appear that the level of diagnostics for the "total vehicle" is not growing at the same rate. The diagnostics that are available for today's vehicle, and the standards that support their development, have largely focused on the individual components.

When there is more than one electronic component on a vehicle, there is a natural desire to minimize the cost of any single major component by reducing the number of sensors required. One solution to this problem is to design the sensors to share output with several major components. SAE/TMC 11708, "Serial Data Communications Between Microcomputer Systems in Heavy Duty Vehicle Applications" and SAE/TMC 11587, "Electronic Data Interchange Between Microcomputer Systems in Heavy Duty Vehicle Applications" were created to facilitate information exchange between stand alone microcomputer-based modules. IQ addition to reducing the need for redundant sensors on the vehicle, the standard enables electronic dashboards to present vehicle status information to the vehicle operator, and allows off-board communications to be developed for servicing vehicle electronic controls.

The heavy duty industry's inexperience with electronics has sometimes hampered the diagnosis of mechanical problems because of "electronic paralysis." Inexperienced personnel can lose their basic (mechanical) common sense when faced with a problem on an electronically controlled vehicle. The solution to this paralysis is to educate dispatchers, operators, and service technicians. Manufacturers also need to share in the solution by continuously improving system diagnostics. The industry needs to do whatever is required to make sure that mechanical system problems can be correctly diagnosed when the electronics detect a symptom or fault.

One area where the industry has begun an effort to encourage a more consistent diagnostic environment is the TMC work on a standard diagnostic scan tool. Because each manufacturer has taken a slightly different approach to diagnostically supporting their component, the result has· been a multitude of individual tools and a variety of troubleshooti~g techniques. The goal of the TMC work is to identify a tool platform that can accommodate all manufacturer-specific programs needed to troubleshoot a vehicle. A standard diagnostic scan tool would reduce some of the need for proprietary tooling and provide a consistent "look and feel" to the service technician for all components. While there will be a reduction in the number of "physical" tools required with the standard scan tool, it can be argu~ that it does not provide reduction of "logical" tools.

The engine fault indicators or dash fault lamps are examples of what happens when the individual manufacturers develop their diagnostics according to their own component

71

Appendix A

needs. Some manufacturers have two lamps, others have one. The number of digits for codes that are flashed and what a given code means varies from manufacturer to manufacturer. In addition, the need for enabling the diagnostic codes is. inconsistent. With the advent of J1587 and its standardized Failure Mode Identification (FMI) coding structure, there is opportunity for removing inconsistency. In summary, when manufacturers address only their own component point of.view, they arrive at different solutions to the same diagnostic problems.

The growth in availability and capability of electronics· on heavy duty vehicles has increased information and functional integration and is making the component-focus approach to diagnostics insufficient. No single component or chassis manufacturer can overcome the obstacles to the creation of the vehicle diagnostic environment. To the extent that the vehicle diagnostic ~nvironment requires an "integrated" approach, it will take an "integrated" effort to create it.

72

Appendix A.

Stepper, Mark R., "Data Link Overview for Heavy Duty Vehicle Applications," SAE 902215, Cummins Electronics Company, Inc., Columbus, Ohio, 1990.

Data link interfaces have become a requirement for the heavy duty vehicle industry because of the need to share information among individual subsystems. Therefore, it is important for the industry to be familiar with the existing heavy duty vehicle serial data communications standards. SAE has addressed the need to share information among individual subsystems.

There are several benefits to be gained by connecting all subsystems to a single data link1 but the two major benefits are single-point servicing and information routing. Vehicle servicing is easier because the service person has only one connection point to locate rather than one point for each subsystem.

·The author presents the serial data communications adopted in SAE Recommended Practices 11708, 11587, and 11922 as well as 11939, which is currently under development by the Truck and Bus Control and Communications Network Subcommittee. An overview of each standard· is presented below.

11708. The 11708 recommended practice addresses specifications for the physical layer and part of the data link layer. Basically it consists of four requirements that identifies the hardware and minimum protocol specifications for each of the connecting subsystems. Three of the requirements fit into the physical layer category and the final requirement treats the data link layer.

The first requirement covers hardware specifications and defines the unit load or the maximum number of subsystems on the same data link. The unit load definition quantifies voltage and current requirements, output impedance, termination and filtering characteristics, maximum number of subsystems allowed per network, the dominant bit state in order to force collision detection, and the proper circuit biasing to allow operation of the data link. The next requirement covers the characteristics of the transmission line or cable. These characteristics include the maximum line length; the specific size of each wire in the twisted pair; the number of twists per inch and the termination and filtering requirements. The third or last physical requirement includes specifics on timing to which both the hardware and software must adhere to be able to interface to the data link. Hardware and software jointly must be able to perform the following functions:

• Determine if the start of the message has begun, • Stop transmitting a message at the end of the current character if the transmission of

another message has begun, • Determine when the data link is available to transmit a message, and • . Minimize the blind time through the data link access procedure.

· The fourth requirement identifies part of the Open Systems Interconnect (OSI) Model data link layer. It defines the identifiers and message frame format. The message· identifiers

73

Appendix A

are in sections which align with different message frame formats. There are currently five sections identified. Section one is for company proprietary communications; characters after the message identifier are not identified. Section two is for J1922 formatted messages. Section three is reserved for assignment by the J1708 committee. Section four is for message identifiers that are unassigned and available for use, and section five is for J1587 formatted messages.

J1587. J1587 completes the definition of the data link layer and addresses the application layer. The physical layer for J1587 remains the same as specified in J1708. Source and destination endpoint identifiers need to be defined in the data link layer. J1587 defines the format of parameter identifiers as labels and as commands. J1587 also defines the message identifiers for use as follows:

• The first character in a message is the source of that message • A character within a block defines the destination for that block or source for which

the parameter identifiers and data apply

The majority of the J1587 document relates to the application layer and contains definitions of the assigned parameter identifiers. J1587 defines the parameter identifiers and data by scaling data for labels and providing unique data field assignments for commands. J1587 also assigns a message identifier to each subsystem.

Many options are available through J 1587 for subsystem designers because of its flexibility. A summary of J1587 application notes follows.

• A request can be separated from its response by many other messages such as other requests or broadcasts. ·

• Several requests can be packed into one message. • There are no specifications for acceptable response times, therefore a requesting

subsystem must recognize that responses can be delayed and should not assume that a message has been lost.

• If data are needed on a repeated basis, it is preferred that it be set up as broadcast data.

• Broadcast data should be packed into as few messages as possible. • There shoul~ be some method of modifying what data are broadcast from a particular

subsystem. • Subsystem-specific requests should be used anytime information is desired from only

one subsystem. • If the data do not arrive after a predefined time period, parameter timeouts should

occur so that proper action can be taken. • Create a user application document that fully defines data link usage during vehicle

. operation.

J1922. The physical layer for Jl922 remains the same as specified in Jl708, with the exception that one of the defined messages is. 22 bytes instead of the maximum 21 bytes. As

74

Appendix A

with 11587 the application and data link layers are defined with J1922. The desire to have more data throughput for J1922 caused the separation of the data ·link and the application layers to be less definitive. The J1922 data link layer defines the following.

• It defines message identifiers 69 to 86 for its use. • It defines that operating conditions and requests are to be formatted in position

dependent data messages. • It defines the following three basic message types per subsystem plus the engine

current gear request and the transmission's corresponding response: broadcast, initialization request, and initialization response.

The J1922 application layer defines control modes available to be commanded (speed, torque, and torque and speed limit); the maximum number of network connections as 4 (engine, transmission, antilock brake/traction control, and retarder subsystems); defines all messages· and update rates to keep the data link utilization below 70 percent; and assigns message identifiers to subsystems.

J1939. The layers needed for the heavy duty vehicle local area network are addressed in the J1939 specification. A small amount of the work is needed in the network layer; however,· most of the content and work needed to complete the 11939 specification will be done in the physical, data link and application layers. In the physical layer the J1939 specification defines the subsystem unit load (maximum number of subsystems on the same data link), and the termination and filtering of transmission lines for 1 OOk to 350k baud. With regard to the network and data link, the following specifications were defined:

• The use of controller area network (CAN) protocol, • The message frame format with regards to how to determine source, destination,

control and data fields, • The communication mode with regards to commands, responses, acknowledgements,

and proprietary modes, and • Error handling and resolution.

The application layer specifications addressed by J1939 are the application needs with respect to powertrain control, information sharing, and diagnostics. Data characteristics such as scaling resolution, priority, latency requirements, accuracy, update· rates, and data definitions are also included. Table 10 is a summary of the information provided by the author.

75

Appendix A

SAE

BOSCH

ISO

Table 10. Comparison of SAE, Bosch, and ISO Heavy Duty Vehicle Serial Data Communications Standards

J1708· (Jan. 1986)

J1587 (Jan. 1988)

J1922 (Nov 1989)

J1939 (not yet published)

CAN-Data Link Layer (approx. 1986)

ISO 7497 (version 1, 1984)

7498/DAD1

Serial Data Communications Between Microcomputer Systems in Heavy Duty Vehicle Applications

Electronic Data Interchange Between MicrOcomputer Systems in Heavy-Duty Vehicle Applications

Powertrain Control Interface for Electronic Controls Used in Medium Duty and Heavy Duty Diesel On-Highway Vehicle Applications

Currently under development by the Truck and Bus Control Communications Network Subcommittee

Controller Area Network

Open Systems Intercqnnection-Basic Reference Model

Addendum 1: Connectionless Model

7498/PDAD3 Addendum 3: Naming Including Addressing

Describes the electrical characteristics a subsystem must have in order to plug into and access the data link to sent or receive messages at 9600 baud (bits/second). Source addresses or identifiers (MIDs) are defined. Applications include proprietary service tools and proprietary products.

Defmes a set of MIDs that use a specific message frame format. This message frame format defines source and destination addressing techniques. It also defines specific commands and data labeling and their range, resolution, format, and update rates. Applications include information sharing and diagnostics.

Defines a set of MIDs that use a specific message frame format. The message frame formate defmes the source· and destination identifiers as well as the data to be sent and its range, resolution, format, and update rate. Applications for powertrain control functions.

Defines all the hardware and software requirements for complete subsystem interconnections from the physical layer to the application layer. Applications will include information sharing, diagnostics, and low and high bandwidth controls.

A serial data communications protocol that is owned and licensed by Bosch. It provides a standard message frame and defines how this message frame is generated and received. It defines portions of the data link layer.

A model used to aid in the development of specifications related to subsystem interconnection. It outlines a layered approach to defining subsystem interfaces.

Source: Stepper, Mark R., "Data Link Overview for Heavy Duty Vehicle Applications," SAE 902215, Cummins Electronics Company, Inc., Columbus, Ohio, 1990.

76

Appendix A

Spivack, H.M., D.ifferential Transducer for Vehicle Diagnostics, U.S. Army TankAutomotive Command, Research, Development and Engineering Center, Warren, Michigan 48397-5000, Contract Number DAAE07-86-C-R088, February 1990.

The U.S. Army Tank-Automotive Command (TACOM) diagnostic program for internal combustion engines and vehicle maintenance mandated that continuous analog differential pressure measurements be provided. Differential transducers were required to determine pressure losses caused by incipient malfunction, clogging and build-up of foreign particles in automotive filters, hydraulic components, air, water, or other fluid flow components. Previously, equipment used in the STE/ICE program Diagnostic Connector Assembly (DCA) utilized discontinuous Switching alarm signals to indicate a condition requiring immediate servicing attention.

TACOM contracted with West Coast Research to conduct a research and development effort to provide optimum selection and integration of materials, manufacturing processes, sensing elements, and test procedures in an economical configuration. The research led to the development of three differentiaJ transducer models which would fulfill the goals of the program. Continuous analog differential transducers were shown to be producible in composite polymer, aluminum casting, or computer-controlled machining of bar stock. Each of the materials and the corresponding manufacturing process have resulted in effective procedures, .. which are modest in cost and comparably priced. The accuracy of results are similar to, or better than, more conventional transducer performance.

77

Appendix A

Wing, R. Gregory and Uttamsingh, Ranjeet, "AI Based Diagnostic Support Systems for the Trucking Industry," SAE 902218, Synetics Corporation, 1990.

The process. of recording, troubleshooting, and repairing trucks, along with training mechanics, is in a process of transition. Today's trucks are increasingly equipped with complicated electronics and complex devices such as electronic control modules (ECMs). As a result of this increase in complexity, the trucking industry will soon be required to employ advanced diagnostic technologies and information to repair vehicles. However, because of the variety of truck component options and configurations that currently exist, the complexity of the diagnostic systems that will be required is increased.

In order to maintain or increase the overall quality of vehicle repair, a decision support system for vehicle repair needs to be implemented. The major components of this system as defined by the authors include:

• A knowledge acquisition system which can be used by each component manufacturer to develop "expert system" diagnostic knowledge bases for each of their products,

• A shop bay computer system which can be used by the mechanic and has diagnostic and repair procedures embedded in an expert system along with "on-line" documentati?n and graphics,

• A repair facility system which can integrate the information acquired during the mechanic's repair session with the appropriate billing, inventory, and vehicle maintenance system, and

·• An original equipment or component manufacturer's system which can provide all product diagnostics and technical documentation, via computer networks, to the repair facilities and shop bay systems.

The-primary challenge is to provide mechanics with expert· diagnostic and repair information so that they can continue to perform in an efficient manner. The use of "Model Based Reasoning" allows diagnostic knowledge bases to be developed by a product repair person in a relatively simple and fast manner. The most effective approach for the mechanic would involve .the integration of a diagnostic expert system with on-line documentation and management systems. Several industries (i.e. complex medical equipment such as CT scan.ners, military aircraft, and computer systems) have chosen this direction and the impact has been significant.

78

Appendix·A

Department of the Army, Direct Support and General Support Maintenance Manual. lncludine Repair Parts and Special Tools List: Simplified Test Equipment for Internal Combustion Eneine. Reproerammable <STE/ICE-Rl. Washington, D.C., 1989.

The Simplified Test Equipment for Internal Combustion Engines - Reprogrammable (STE/ICE-R) is a testing system used for performing tests and measurements on the vehicle. In addition to acting as a conventional digital multimeter to measure voltage, current and resis~ce, it is also capable of measuring pressure, speed, compression unbalance, engine power, and some specialized battery and starter evaluations. STE/ICE-R is powered by the vehicle's batteries. The complete system includes:

• · Vehicle test meter (VTM), which performs the measurement and analysis functions of the STE/ICE-R systems,

• Transducer kit (TK), which is a collection of transducers, adapters, and fittings that permit the STE/ICE-R to be used as a general purpose measurement system for any application. This allows the STE/ICE-R to be used anywhere that you want to measure voltage, current, resistance, pressure, or speed,

• Cables,

• Transit case, and

• Technical publications.

A Diagnostic Connector Assembly (DCA) is an electrical harness on the vehicle that allows the STE/ICE-R to be powered and to make measurements of key vehicle signals from a single connections. In addition to many basic electrical signals such as starter voltage and current, it includes engine speed and fuel supply pressure. The STE/ICE-R can make TK measurements at the same time that it is connected to the DCA. Table 11 is a summary of test applications for the STE-ICE-R.

79 .

Table 11. STE/ICE Test Procedures

Test Type and Description Requirements Typical Application Number

Engine RPM Measures engine speed in the range 50 to 5000 RPM. At Test requires DCA Check engine speed. I

(Average) Test #10 speeds below 50 RPM the VTM will display 0. At speed hookup only. above 5,000 RPM the display may give a· false reading.

Power Test Measures an engine's power produci:fig potential in units of Test requires DCA Check engine power in units of RPM/SEC. (RPM/SEC) Test #12 RPM/SEC. hookup only.

Power Test (Percent) ·Measures the percentage of engine's power producing potential Test requires DCA Check engine power. Test #13 as compared to a good engine. hookup only.

Compression Compares the compression between the highest and lowest Test requires DCA Check compression unbalance of engine with VTM Unbalance Test #14 cylind~rs and displays the unbalance in the percent. hookup only. powered from battery of vehicle being tested.

Fuel Supply Pressure Measures the return pressure, in order to detect line blockage, Test requires DCA Fuel Supply Pressure. (psi) Test #24 leaks, or insufficient restrictor back pressure. hookup only.

Pressure (psi) 0 to Measures pressure· in the range of 0 to 1000 PSIG. Test requires the use Oil Pressure. 1000 Test #50 of TK adapters and

transducers

Battery Voltage Test Measures battery voltage in the range 9 to 32 volts. The Test requires DCA Check battery voltage. #67 voltage is measured directly at the power source of the VTM, hookup only.

and may be done with the vehicle operating or shut down.

Starter Motor Voltage Measures the voltage present at the starter motor positive Test requires DCA Check starter motor voltage. Test #68 terminal, in the range of 0 to 32 volts. hookup only.

Starter Negative Cable Measures the voltage drop on the starter path. A high voltage Test requires DCA Check starter negative cabl~ voltage drop. Voltage Drop Test ( > 2V) indicates excessive ground path resistance. hookup only. #69

I

Starter Solenoid Volts Measures the voltage present at the starter solenoids positive Test requires DCA Check starter solenoid volts. I

Test#70 terminal. hookup only.

Table 10. STE/ICE-R Test Procedures Continued)

Test Type and . Description Requirements Typical Application Number

Starter Current Measures ·the average starter current in the range 0 to 1000 amps .. Test requires DCA Check starter current. Average Test# 71 hookup only.

Current First Peak Measures the overall condition of the complete starting system. Test requires DCA Check condition of starting system on CI Test #72 hookup only. engines with VTM being powered from

vehicle being tested.

Battery Internal Measures· the internal battery resistance. Internal battery resistance Test requires DCA Evaluate batteries on CI ·engines with VTM Resistance Test #73 is the measure of the state of the batteries. hookup only. being powered from battery of vehicle being

tested.

Starter Circuit Measures starter circuit resistan~. Test requires DCA Check resistance of complete starting system Resistance· Test #74 hookup only. in CI engines with VTM powered form

batteries of vehicle being tested.

Battery Resistance Measures the change of battery resistance. Test requires DCA Evaluate batteries in CI engines with VTM Change Test #75 hookup only. powered from batteries of vehicle being

tested.

Battery Current Measures current to or from the battery. Test requires DCA Evaluate batteries in CI engines. Test #80 hookup only.

DC Voltage 0 to 45 Measures voltage in the range of -45 to 45 volts. The VTM is Test requires the Fuel solenoid, Starter solenoid, Alternator Volts DC Test #89 used as a DC voltmeter with the decimal point in the correct use of the TK Output, or Any DC Voltage measurement.

position. This test must be done with the component being tested adapters and turned on. transducers.

DC Current 0 to Measures the DC current in the range of 0 to 1500 amps. The Test requires the Alternator output, average starter current, 1500 Amps DC VTM is used as an ammeter with the decimal point in the right use of the TK battery· current, and any DC current up to Test #90 position. This test may be done with the vehicle/equipment adapters and 1500 amps.

operating. transducers.

Table 10. STE/ICE-R Test Procedures (Continued)

Test Type and Description Requirements Typic:al Application Number

Resistance and Measures resistance in the range of 0 to 4500 ohms. The Test requires the use Continuity checks, resistance measurements, and Continuity to 0 to 4500 VTM is used as an ohmmeter, and test results are always of the TK adapters . switch and relay functions. Ohms Test #91 displayed with the decimal point in the device being tested and transducers.

will adversely affect test results. Make sure the circuit or component being tested is shut off.

Source: Department of the Army, Direct Sugport and General Suuport Maintenance Manual, Including Repair Parts and Special Tools List: Simglified Test Equipment for Internal Combustion Engine. Regrogrammable (STE/ICE-R). Washington, D.C., 1989.

Appendix A

Foy, Lucinda A., "Real-Time Processing Applications for Heavy-Duty Trucks," SAE 861066, Charlotte Technical Center, Freightliner Corporation, 1986.

Real-time control systems have continued to advance along with other electronic devices and are now being utilized in the heavy-duty truck industry. These systems are designed to electronically control events as they happen and provide up-to-date diagnostic information, consequently increasing the operating efficiency, reliability, and safety of the vehicle. Real-time control systems have potential for a variety of applications beyond those that are currently being used in the trucking industry.

Diagnostic systems that can record intermittent problems give more accurate assessments of the problems, thereby increasing reliability. Being able to diagnose a problem and correct it immediately prevents catastrophic failure resulting in the vehicle being out of service. With the use of a real-time control system, the number of mechanical parts can be reduced significantly. An example of this is the electronic transmission, which optimizes or eliminates the use of the clutch. This reduces the number of mechanical parts for the electro-hydraulic automatic transmission and reduces wear when clutch usage is optimized for the electronically shifted mechanical mechanism.

Several real-time systems are currently available or under development for use in the heavy duty trucking industry. Examples of these are the electronic engine, transmission, and anti-lock braking systems. The major disadvantage of these systems is that they operate primarily as stand-alone systems. Different units on the same vehicle measure and process signals redundantly. Jl708 specifies the format for communication between modules, although it cannot presently be used for real-time control. This problem could be resolved with the development of a high-speed data link. Because total system design is critical, it is necessary that a high-speed data link for heavy-duty vehicles be developed. To optimize system performance and minimize redundancy, it must meet the following criteria:

• Open system flexibility, • Minimum processor burden, • Maximum programmer transparency, • Guaranteed data consistency, -• Faster transmission rate, • High reliability in noisy environments, and • Reduction in manufacturing cost.

With the advent of high speed data communications, the vehicle will incorporate more and more electronics until control systems can be separated into four major categories. These are: trailer computer, cab computer, powertrain computer, and chassis co01puter.

The electronic engine and electronic transmission could be optimized by using a single computer to control both systems. This computer would be the powertrain computer and would fully integrate the operation of the engine and the transmission, so that the engine would have direct knowledge of the transmission and vice-versa. An example of how this

83

Appendix A

would be beneficial is the shifting of gears. Shifting would be optimized with a more direct relationship between the engine and transmission. Also, when a problem arises with one unit, the other unit could compensate to avoid further damage thus providing a "limp home" feature.

The second unit would be the chassis computer, which controls anti-lock braking, tire pressure, load sensing, and other chassis functions. The ability to control tire pressure in relation to load sensing would make anti-lock braking more effective. With the addition of a collision detection device, the actual braking force applied could be determined by the distance between the vehicle and the obstruction.

The third area of control would be the cab computer, which would function as the data retriever for the complete vehicle. This will be the system which provides all the information for the displays in the vehicle. All the data smoothing would take place in this computer, in addition to other functions including the vehicle recorder and heating and air conditioning controls.

The fourth computer would be the trailer computer, which could be used to administer the anti-skid braking for the trailer, monitor refrigerated units, and accomplish load sensing. A monitoring system .could be installed on hazardous waste and materials haulers that could warn of leaks ·and other possible problems.

Appendix A

Malecki, Richard L. and Snyder, Charles R., "Diesel Electronic Engine Controls in the North American Heavy Duty Truck Market," SAE 861077, Navistar International Corporation, 1986.

Deregulation has had a tremendous impact on all sectors of the transportation industry. The heavy duty truck of today and the future willhave to provide its customer with improved efficiencies not previously achieved in the transportation industry. In addition to the increased. economic pressures on the industry, several regulations are causing significant changes. These regulations and proposed regulations affect vehicle noise, exhaust emissions, and safety. Due to economic, legislative, and safety issues, the truck of the future will be drastically different from today's product.

Truck manufacturers and component suppliers are turning to microcomputers, electronic sensors, communication links, digital displays, and satellite communication systems to make trucks safer, easier to operate, and more efficient. The two basic types of electronic systems applicable to on-highway trucks, as identified by Caterpillar, are control systems and monitoring systems. They define control systems as performing an active role in the operation of the vehicle by regulating various processes, while monitoring systems evaluate the processes for display to the operator or to be recorded for future analysis.

Electronic engine control systems will play a major role in lowering the operating costs of diesel engines. All of the major North American engine suppliers are, or will be, making available controls on engines. Many electronic engine control systems are being adapted to engines that were original! y mechanical! y fueled. Some engine suppliers are developing new engines that are being tailored specifically to electronic engine controls.

Electronically controlled diesel engines have proven performance advantages as compared to mechanically fueled engines. Along with the added performance, diesel electronic engine controls can provide the extra value of certain features that are not practically feasible with mechanically fueled engines. These features can aid in driver convenience, economic performance, safety, and maintenance. Depending on the engine, the first generation diesel electronic engines will be capable of providing some benefit in the following areas: cruise control, road speed governing, engine speed governing, diagnostics, and emergency engine shutdown capabilities.

One feature of diesel electronic engine controls is electronic diagnostics. Electronic diagnostics range from reading out the diagnostic codes from instrument panel lamps to offvehicle diagnostic tools. Engine control systems will also be able to record real time fault information that may be of value to the service technician at a later date. The engine control system can assist maintenance personnel in troubleshooting electronic components and sensors, as well as engine faults such as plugged injectors and low cylinder compression.

85

APPENDIX B

Diagnostic Tool Information

?

Diagnostic Tools for

Computer Controlled Components

Available Now or in the Near-Term

Useful Tool Capabilities for Diagnostics

• Read J1587 PID Data • Read/Write Proprietary Data • Parameter Programming

- Customer Parameters - Dealer Parameters

• Control Program Modification

Useful Tool Capabilities for Diagnostics (Cont•d)

• Signal Measurement • Public Diagnostic Tests • Prop.rietary Diagnostic Tests • Integrated Electronic Technical Manuals

(IETM) • Flight Recorder

• Pluses

Hand-Held Tool Pluses and Minuses

- Relatively ·inexpensive -Provides a •standard• tool - Manufacturer cartridges are available

• Minuses - Generic cartridges are ineffective - Proprietary computer design -Real capability requires manufacturer cartridge

Summary of Hand-Held Tools

Cartridge

I Generic Heavy Duty

Allison

Caterpillar

Caterpillar ECAP

Detroit Dieaet

Cummine COMPUUNK

Cummins ECHEK

Eaton

MackV·MACK

WABCOABS

5

• Pluses

l Product functions

~ I' ·~ ~-r;"d; :-. 8 "-: ~ , ;F "" It' .$ ... I

if (to .N q ~ . ~ t ·b ~ ~ ~~ ~ ~ ~ ~ ~ .ff ~ ·~ ., ~ ~ ~ ~ <~//;<E ~/.! ~ ~ j ~

• • • • • • • • •

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Snap-On Toots ;, deveqmg camdges lor theirMT2500 teamer.

PC-Based Tool Pluses and Minuses

• • • • •

• • • • •

- •open• computer design (lots of options)

-

- Supports sophisticated diagnostic programs -More potential for effective generic tools - Potential for lots of suppliers

• Minuses - Relatively expensive to very expensive - Real capability still requires the

man ufactu rer•s program

(

Summary of PC-Based Tools

Product

Caterpillar Service Information System (SIS) • • • • • • • • • • Cummins Electronic Software Database and Network (ESDN) • • • • Mack V -MAC Service • • • • • • • • Diaqnostics Pr99ram

Summary

• Generic cartridges have limitations.

• Hand-held tools support most products.

• Manufacturer cartridges are required. • PC-based tools (software and hardware)

are available.

• There is limited competition in the truck tool market relative to passenger car.

-

!Company: MPSI Product Fooctions

0 l 0 l 0 Product Description: Special Fulctions & Strengths :

101004 Prolink diagnostic reader • Flight recorder

• 4 line, 80 c.haracter LCD display • RS-232 port supports printer and PC interfaces.

• Large, color<oded keypad

• 10 ft data cable

• Easily updated through hardware/software cartridgfl.s.

0 Indicates basic capability~ requires additional software/hardware to pt:riom1 function.

I Company: OTC and OEMs

• Product Description:

3824239 Cummins Diagnostic Cartridge

3824271 Cummins Programming Cartridge

Cover~ PACE, PT PACE.R, CF.LECr products.

Has general purpose J1708 function built-in. Can perform all authorized functions on any application that OTC has released cartridges for (i.e.1 Ford1 GM1 Chrysler, and impoits) Low cost cartridge upg:ades.

Product Description:

201023 Rockwell I W ABCO ABS Cartridge


201024 Caterpillar Cartridge

Reads syste~n fault codes.

Display pardrneters and set'.sor values.

• Flight recorder

• Fault code display

•Includes harness adapter

•Customer programrnabl~ parameter interface

• Perfonns cylinder rut-out BTM sweep test Shut off solenoid test Exhaust brake solenoid tEst

• Printer output

MPSI


201007 DDEC I & II Cartridge, version 4.0

~Co~: MPSI


201010 V-MAC Canridge1 \'ersion 2.0

Product Functions

$399.00

• Flight recorder

• Diagnostic code display

• Parameter I sensor readout

• Customer Reprogram interface

• Special tests (Cylinder cut-out)

• Printer Output

$469.00

• Flight recorder

• RS-232 PC Link cable included

•Diagnostic code display

• Customer parameter reprogramming

• Printer output

!Company: MPSI Product Functions

Product Description: Special Functions & Streng1hs:

I 20 I 009 Allison ; ransmlssion Cartridge. verslon 2 0 • Flight reC"order (snapshot for trouble shooting)

• Fault code display

• l'atameter read-au l

• Printer output

Product Description: 201011 Heavy Duty Standard cartridge, wrston 2.0 • Fllght recorder {snap-shot)

• Faull code display

• JI587 parameter infonr.ation display

• Printer output

assess the feasibility of a standardized electronic diagnostic

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