4. common rail direct injection

8/12/2019 4. Common Rail Direct Injection

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COMMON RAIL DIRECT INJECTION

Dr. K. C. VoraHead, ARAI Academy

The Automotive Research Association of India, Pune


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CONTENTS

Introduction

System Types & Generation

Common Rail & Emission Strategy

System Validation & Tests

Project Milestones


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TECHNOLOGYDRIVERS

Emission regulations (Exhaust gas and Noise)

Further fuel economy improvements

Further improvements in

Reliability

Durability of engine/vehicles

Competitive costs and prices

INTRODUCTION


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FUEL INJECTION SYSTEM - FUNCTIONS

To meter the quantity of fuel to be injected.

To inject fuel at the right time in the cycle. This implies accurate timing

of injection as a function of engine speed and load.

To mix fuel with air effectively in the short period of time available. This

means that the fuel has to be introduced at very high energy levels

All the above have to happen consistently cycle by cycle, cylinder to

cylinder and over a period of time.


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5

Main Functionsof Diesel Fuel

Injection System

Injection Timing

Control

Atomization

and Penetration

Injection Quality

Control

FUEL INJECTIONSYSTEM - FUNCTIONS


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FUEL INJECTION SYSTEM - FUNCTIONS

Fuel Injection Pump Fuel quantity delivered

Injection Timing

Rate of Injection

Idle & Max speed Governing

Injector

Injection pressure

Spray pattern Filter

Removal of contamination from fuel Protect Fuel

Injection equipment


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Cam driven FIE

Pressure generation and injection are coupledCourtesy: Mico Bosch India.

CAM DRIVEN FIE


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Courtesy: Mico Bosch India.

DEVELOPMENT TRENDS IN CAM DRIVEN FIE


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COMMON RAIL & EDC FIP



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PRESSURE GENERATION AND FIE



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TECHNOLOGY DRIVERS-EMISSION



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TECHNOLOGY DEMANDS ON FIE

High pressure potential (> 2000 bars)

Realisation of the ideal rate of injection via pressure modulation

alone

Capability of realising staged (boot) as well as pilot injection where

pilot is separated from the main injection

Flexibility of selecting start of injection as well as end of injection

Moderate initial rise of main injection

Sharp cut off of the injection end

Flexibility of selecting peak injection pressure

Provide option to automatically change rate shape according to

engine speed and load


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COMMON RAIL SYSTEM



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What is a Common Rail?

Common Rail is a1. Modular,

2. Electronic Controlled,

3. Diesel Fuel Injection System

COMMON RAIL SYSTEM


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COMMON RAIL SYSTEM

Special Characteristics

1. Injection Pressure is produced

and governed relatively.independent of the Engine

Speed and can be selected

freely within a wide range.

2. Injection begin and InjectionQuality can be freely selected

(EDC function).


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How are the main characteristics of CR

system achieved?

1. CR uses and intermediate HighPressure Accumulator (Rail)

2. Uses Electronic Control of Injectors

(use of Electro-magnetic valves)

COMMON RAIL SYSTEM


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COMMON RAIL SYSTEM



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COMMON RAIL SYSTEM



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COMMON RAIL SYSTEM



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COMPONENTS OF CRDI SYSTEM

CR

System

HP

Pump

Injectors(set of 4)

Rail

Sensors

ECU

Low

Pressure

Side

High

Pressure

Side

Electronics

Sedimenter

Priming Pump (Pear Type)

HP Pipes

(set of 5)

Filter

Low pressure pipes with quick fit couplers


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COMMON RAIL SYSTEM



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ELECTRONIC DIESEL CONTROL



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CRS- ELECTRONIC CONTROL UNIT (ECU)



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CRS- ELECTRONIC CONTROL UNIT (ECU)

ECU mounting Hints

Boundary condition influencing installation of ECU

Wiring harness: 150mm from ECU

Vibration: 4 plane screwing points

Temperature: < 60C

Humidity: Away from water splash

Chemical resistance: Away from battery


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SENSORS FOR CRDI ENGINE

Sensors

On CR

System

On

Engine

On

Vehicle

Fuel Temp

Rail Pressure

Engine Speed (Crankshaft)

Engine Phase (Cam Shaft)

Throttle Pedal

Knock Sensor

Water Temp

Intake Air Temp

and Boost

Pressure

Vehicle Speed

Air Mass Flow

Cruise Control

Water Sensor

Barometric Sensor


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SENSORS ON CRDI ENGINE



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ORIENTATION ON CRS COMPONENT: COMMON RAIL


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ORIENTATION ON CRS COMPONENT: COMMON RAIL



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HIGH PRESSURE PUMP OF COMMON RAIL SYSTEM



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Servo valve principle

Solenoid actuator

200 - 1600 bar operatingpressure

pilot quantity 1-3 mm3

Extremely fast response

Low leakage system

Capable of multipleinjections

INJECTOR


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CRS ADVANTAGES

Separation of pressure generation and injection allowing flexibilityin controlling both the injection rates and timing.

Fuel pressure does not depend on the engine speed and load

conditions

(This feature differentiates the common rail from conventional

injection systems) High injection pressures and good spray preparations are possible

even at low engine speeds and loads.

Capability to deliver stable, small pilot injections can be used for

decreased NOx emissions and noise.

Option for post injections may be used together with such emissioncontrol technologies as particulate filters, lean NOx catalysts, or NOx

adsorbers.

Fuel pump operates with low drive torque.


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SYSTEM TYPES



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SYSTEMTYPES



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COMMON RAIL SYSTEM


1600bar with CP1H, Gear pump (feed), Metering unit, Injector, Rail, ECU


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COMMON RAIL SYSTEM

1600bar with CP1H, Gear pump (feed), Metering unit, Injector, Rail, ECU


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COMMON RAIL SYSTEM- COMMERCIAL VEHICLE (CRSN)



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CRS SYSTEM FOR OFF HIGHWAY APPLICATIONS-

BASIC SYSTEM


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SYSTEM COMPONENTS : CRS



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SYSTEM MANAGEMENT


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CONTENTS

Introduction completed

System Types & Generation completedCommon Rail & Emission Strategy


Project Milestones


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COMMON RAIL SYSTEM & EMISSION


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COMMON RAIL SYSTEM & EMISSION


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SYSTEM VARIABILITY REDUCTION

Dispersion management is one of the great challenges.

Low variation and high precision are required during the entire

vehicle life

Euro 5Euro 6 Proposal

PM(

g/km)

NOx (g/km)

Euro 4

Future

dispersio

n

Enabling technologies:

Fast/Precise fuel

injection systems

Fuel injection control

strategies

Combustion sensors

Performing EGR

components


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CONTENTS


System Types & Generation completedCommon Rail & Emission Strategy completed


Project Milestones


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VALIDATION TESTS ON SYSTEM, ENGINE, VEHICLE

System endurance test on bench

Load collective measurement on vehicle

Low pressure circuit measurement on vehicle

Temperature measurement on vehicle

Vibration measurements on engine and vehicle

Fault monitoring and diagnostics on vehicle

Endurance test on engine

Mileage accumulation on vehicle Summer, winter, altitude test on vehicle


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OMMON RAIL SYSTEM LOAD COLLECTIVE MEASUREMENTS


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CONTENTS


System Types & Generation completedCommon Rail & Emission Strategy completed

System Validation & Tests completed

Project Milestones


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PROJECT MILESTONES


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CUSTOMER PROJECTS : INTERFACE & INVOLMENTS


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COMMON RAIL SYSTEM & DIAGNOSIS


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PROJECT TEAMS


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COMMON RAIL SYSTEM & FUEL


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CONCLUSIONS


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Thank You!

4. common rail direct injection

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