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MaxxForce® 15 Engine Training - Program 1

Study GuideTMT-121111

Study Guide M

axxForce® 15 Engine Training - Program

1 TM

T-121111

©2011 Navistar, Inc. 4201 Winfield Road, Warrenville, IL 60555.

All rights reserved.

No part of this publication may be duplicated or stored in an information retrieval system without the express written permission of

Navistar, Inc.

INTRODUCTION ................................................................1

MODULE 1: Mechanical System & Engine Brake .......5Section 1 – Overview ...........................................................5Section 2 – Timing Sensors ...............................................6Section 3 – Engine Brake ...................................................6Section 4 – Camshaft & Cylinder Head Spacer Plate ...8Section 5 – Gear Train & Crankcase Fasteners ..............9

MODULE 2: Lubrication System ..................................13Section 1 – Overview .........................................................13Section 2 – Component Lubrication ...............................14Section 3 – Remote Mounted Centrifugal Oil Filter ...14Section 4 – System Sensors ............................................15

MODULE 3: Cooling System ........................................19Section 1 – Overview .........................................................19Section 2 – Unique Elements of the System ............... 20Section 3 – EGR Cooler & Coolant Control Valve ...... 20Section 4 – Cooling System Sensors .............................21

MODULE 4: Fuel System ...............................................25Section 1 – Overview ........................................................ 25Section 2 – Remote Mounted Fuel Filter ..................... 26Section 3 – Low-Pressure & High-Pressure Pump ..... 27Section 4 – High-Pressure Fuel Lines and Pipes ....... 28Section 5 – Injector Quantity Correction ..................... 28Section 6 – Fuel System Sensors .................................. 29

MODULE 5: Air Management System ........................33Section 1 – Overview ........................................................ 33Section 2 – Air Induction ................................................. 35Section 3 – Charge-Air Coolers ..................................... 36Section 4 – Air Induction Sensors ................................. 37

Table of Contents

Section 5 – Exhaust Gas Recirculation ........................ 38Section 6 – EGR System Sensors .................................. 39Section 7 – Crankcase Ventilation .................................41

MODULE 6: Cold Start Assist ......................................43

MODULE 7: Aftertreatment System ............................47Section 1 – Overview ........................................................ 47Section 2 – PDOC, DOC, & DPF ..................................... 47Section 3 – Active & Stationary Strategies ................. 48

Part 1 – Downstream Injection .............................. 48Section 4 – Exhaust Sensors .......................................... 49Section 5 – Stationary or Parked Regeneration ..........51

CONCLUSION ..................................................................53

Table of Contents

Introduction

Welcome to 2011 MaxxForce® 15 Engine Training for Technicians.

The goal of this course is to introduce this engine to service personnel who perform maintenance, diagnostics, and repair.

Upon completion of this course, you will be able to locate the engine components, trace the flow of engine fluids, and identify the operation of each system.

This course is divided into an introduction and seven modules.

Let’s take a brief look at the engine’s features, serial number location, and electronic control modules.

The MaxxForce® 15 engine features a dual turbocharger assembly, an engine mounted diesel oxidation catalyst, a two stage EGR cooler, a front located gear train, a common rail fuel system, an engine brake, an overhead camshaft, and injectors with quantity correction.

The engine serial number is located on the crankcase and on the emissions label.

“The goal of this course is to introduce this engine to service personnel.”

Introduction 1

2 MaxxForce® 15 Engine Training - Program 1

For 2011, the first five digits are 1S152. The 152 number indicates the engine’s displacement.

The engine is equipped with a single Engine Control Module, or ECM. Connectors C1 and C2 are for the chassis, E1 is for the engine mounted sensors and actuators, and E2 is for the injectors.

MaxxForce® 15 diagnostic trouble codes are time stamped to aid technicians in the diagnostic process. This information is provided by the Stand Alone Real Time, or SART module.

This concludes the Introduction.

“MaxxForce® 15 diagnostic trouble

codes are time stamped to aid

technicians.”

NOTES

Introduction 3


NOTES

Module 1: Mechanical System & Engine Brake 5

Mechanical System & Engine Brake

Overview

The following components will be discussed in the Mechanical and Engine Brake section: the air compressor, timing sensors, camshaft, cylinder head spacer plate, and the MaxxForce® Engine Brake.

The air compressor is mounted on the left side of the front cover and is driven by the gear train.

There are two types of compressors available. The first type controls air pressure using a governor on the air drier.

The second type of compressor uses a clutch to control system pressure.

Air pressure is supplied from a remote line to the clutch housing.

When the clutch spring pressure is overcome by system air pressure the clutch is released.

Module 1

“There are two types of compressors available.”


Timing Sensors

The engine uses crankshaft and camshaft position sensors to monitor engine rotation. Both sensors are two-wire magnetic pick-up style.

The crankshaft position sensor is located on the left side of the front cover.

The sensor reads a timing disc on the crankshaft.

The camshaft position sensor is also located on the left side of the front cover. The sensor reads the camshaft timing ring located on the camshaft gear.

Engine Brake

The engine brake uses three brake assemblies, six stepped lobes on the camshaft, and lube oil to operate.

Each brake assembly is paired with two cylinders and includes a solenoid valve, two control valves, two master pistons, and two slave pistons.

There are five steps in engine brake operation. The steps are solenoid activation, cylinder pressurization, brake action, pressure release, and brake

“The engine uses crankshaft and

camshaft position sensors to monitor

engine rotation.”

“There are five steps in engine

brake operation.”


deactivation. Let’s start by taking a look at how the engine brake is activated.

When the brake solenoid is activated by the ECM, lube oil flows from the solenoid through the control valve to fill the brake assembly passages. The control valve acts as a one-way check valve to trap oil between the master and slave pistons.

Oil pressure then overcomes the spring pressure of the master piston, causing the master piston to extend and contact the brake rocker arm.

Near the bottom of the intake stroke, the first step on the camshaft lobe pushes against the brake rocker arm. The trapped oil in the brake assembly transfers cam movement from the master piston to the slave piston.

The slave piston pushes on the exhaust valve rocker arm causing the exhaust valves to open. With the exhaust valves open, exhaust back pressure further increases pressure in the cylinder.

As the cam and crank continue rotation, the valves close and the piston is driven against the compression stroke. This allows the engine, through the drive train, to slow the forward motion of the vehicle.

“The control valve acts as a one-way check valve to trap oil between the master and slave pistons.”


Near the top of the compression stroke, the second step of the cam lobe forces the exhaust valves open, relieving compression from the cylinder. This removes the downward push on the piston and increases the braking power of the engine.

During normal operation, when the operator depresses the throttle the ECM deactivates the brake solenoid. This allows the oil in the brake assembly to drain through the solenoid valve.

The master piston spring then retracts the piston from the brake rocker arm and disengages the engine brake.

Some additional conditions that would cause the engine brake to deactivate are: the engine brake switch turned to the OFF position, the clutch pedal is depressed, or engine speed below 800 RPM.

Camshaft & Cylinder Head Spacer Plate

The camshaft is located in the cylinder head and driven off the gear train.

The camshaft gear has eight steel pucks that sit in pockets in the face. The pockets are larger than the pucks

“During normal operation, when

the operator depresses the

throttle the ECM deactivates the

brake solenoid.”


to allow free movement and reduce vibration.

The cylinder head spacer plate is a large shim that compensates for the difference in height between the cylinder sleeves and crankcase deck surface.

Several ports are incorporated into the plate for oil and coolant flow between the crankcase and the cylinder head.

Gear Train & Crankcase Fasteners

The gear train is located in the front of the engine. The crankshaft gear drives the oil pump, cluster gear, idler gear, adjustable idler gear, high pressure fuel pump, air compressor, and camshaft.

Due to variations of thickness in the cylinder head spacer plate and cylinder head gaskets, an adjustable idler gear is needed to set gear lash.

The adjustable idler gear assembly is composed of a plate, pivot pin, and Idler gear. The pivot pin and the slotted bolt holes allow the assembly to pivot. This movement allows the technician to set the gear lash.

“The gear train is located in the front of the engine.”


The MaxxForce® 15 uses both standard and metric fasteners. Refer to the service manual on ISIS® for the specific fasteners used in each procedure.

This concludes the Mechanical & Engine Brake System.


NOTES

Module 2: Lubrication System 13

Lubrication System

Overview

Let’s start our discussion of lubrication by identifying the system components.

The key parts are: the oil pump, the oil cooler, the primary oil filter and the remote mounted centrifugal oil filter.

The oil pump is bolted to the bottom of the crankcase and is driven by the crankshaft gear.

The oil pressure regulator is located in the oil pump housing. The regulator limits the maximum oil pressure.

The oil pick up tube supplies oil to a port on the back of the pump.

After pressurization, a second pipe delivers oil to a passage in the crankcase.

This passage feeds the filter module where oil is directed to the cooler assembly. After passing through the cooler, oil reenters the filter module and passes through the filter. Oil then flows to the crankcase and cylinder head.

Module 2

“The oil pump is bolted to the bottom of the crankcase.”


Component Lubrication

The crankshaft and connecting rods receive oil through oil galleries in the crankcase. The connecting rods have drillings that supply oil to each piston pin for lubrication.

Both turbochargers are lubricated with filtered oil through external supply lines. Oil drains back to the crankcase through oil return pipes.

The air compressor is also lubricated with filtered oil through an external supply line. Oil drains back to the crankcase through the front cover.

Remote Mounted Centrifugal Oil Filter

The MaxxForce® 15 features a remotely mounted centrifugal oil filter. This filter is designed to remove soot from the engine oil.

The centrifugal filter housing has the following ports: oil supply, oil return, and air supply.

The supply port is fed from the engine mounted oil filter housing and the return port feeds oil back to a fitting on the crankcase. The compressed air is supplied from a remote source.

“Both turbochargers are lubricated

with filtered oil through external

supply lines.”


Engine oil flows through the housing to a regulator valve.

When engine oil pressure exceeds 36psi, or 248 kPa, the valve opens and oil enters the element.

Oil flows out of the opposing nozzles. This causes the element to spin at high speeds.

Centrifugal forces allow oil to pass through the filter while trapping debris.

Oil collects in the bowl of the housing. As oil fills the bowl, a float opens the air supply port. This pressurizes the housing, assisting the oil flow back to the crankcase.

After the oil level in the bowl drops, the float closes the air supply port and prevents air pressure from entering the housing.

The centrifugal element is serviceable and must be replaced at every oil change interval.

System Sensors

Two sensors are used to monitor the lubrication system. The first is the engine oil pressure sensor.

“When engine oil pressure exceeds 36psi, or 248 kPa, the valve opens and oil enters the element.”

“The centrifugal element is serviceable and must be replaced at every oil change interval.”


This sensor is located on the left side of the crankcase behind the engine fuel filter. It is mounted in the oil pressure sensor block and has a twist lock electrical connection.

The second sensor is the engine oil temperature sensor. This sensor is located in the oil filter housing. It measures the temperature of the engine oil before passing through the cooler.

The ECM monitors both the pressure and temperature sensors for proper engine operation.

This concludes the Lubrication System.

“The ECM monitors both the pressure

and temperature sensors for proper engine operation.”

NOTES


NOTES


NOTES

Module 3: Cooling System 19

Cooling System

Overview

The main components of the MaxxForce® 15 cooling system are the: coolant control valve, water pump, thermostats, low temperature radiator and the conventional radiator.

The components that are cooled in addition to the crankcase and cylinder head are the: low-pressure charge-air-cooler, oil cooler , aftertreatment injector, EGR valve, EGR cooler, and the air compressor.

Coolant from the water pump is sent in parallel to the oil cooler, the coolant control valve, and both sections of the EGR cooler. Coolant from the oil cooler flows into the crankcase, around the cylinder liners, and into the cylinder head. Coolant then exits the head and enters the thermostat housing at the front of the engine.

When the thermostats are open, coolant flows to the radiator. If the thermostats are closed coolant returns to the water pump.

Module 3

“When the thermostats are open, coolant flows to the radiator.”


Unique Elements of the System

The EGR cooler is mounted on the top right of the engine and has two sections.

In the rear section, coolant flows through the cooler, exits to the coolant adapter, and is then returned to the water pump inlet.

In the front section, coolant flows through the cooler, exits to the coolant adapter, and is then routed to the rear of the oil cooler housing.

EGR Cooler & Coolant Control Valve

The Low Pressure Charge-Air-Cooler, or LPCAC, is an air-to-water cooler located on the right side of the engine. With the cooler and support bracket removed the LPCAC supply and return hoses can be accessed.

The Coolant Control Valve, or CCV, is located at the right front of the engine. This valve controls the temperature of the coolant that enters the LPCAC and the EGR valve.

The CCV has five parts: the coolant supply port, flow valve, mixing valve,

“The LPCAC is an air-to-water cooler

located on the right side of the engine.”


LTR port and the LTR bypass port. The solenoids on the CCV are controlled through Pulse Width Modulated, or PWM signals from the ECM. These signals can be any value between zero and 100% depending on operating conditions.

The flow valve varies the rate of coolant flow to the mixing valve. At 0% duty cycle the flow valve is fully open and coolant to the mixing valve is not restricted. When the flow valve receives 100% duty cycle, it partially closes restricting coolant to the mixing valve.

The mixing valve varies the amount of coolant that passes through the low temperature radiator, or LTR. With a 0% signal to the mixing valve, all coolant flows to the LTR before entering the LPCAC and the EGR valve.

When 100% duty cycle is applied to the mixing valve, full coolant flow bypasses the LTR and is directed to the LPCAC and EGR valve.

Cooling System Sensors

The ECM monitors cooling system operation using the following sensors: Engine Coolant Temperature 1, Engine Coolant Temperature 2 and depending

“When the flow valve receives 100% duty cycle, it partially closes restricting coolant to the mixing valve.”


on the build date, Engine Coolant Pressure 1.

The Engine Coolant Temperature 1 sensor is located on the thermostat housing.

This sensor is the primary input to the ECM for engine coolant temperature. This sensor also allows the ECM to generate a signal for the instrument panel temperature gauge.

The Engine Coolant Temperature 2 sensor is mounted to the coolant manifold at the inlet of the low pressure charge air cooler. The ECM uses this sensor to determine the proper position of the coolant control valve.

Depending on build date, the engine may be equipped with an Engine Coolant Pressure 1 sensor. This sensor is mounted to the supply tube for the rear section of the EGR cooler. The ECM uses this signal to detect low coolant flow, or no coolant flow to the EGR cooler.

This concludes the Cooling System.

“The Engine Coolant

Temperature 1 sensor is located

on the thermostat housing.”

“The Engine Coolant

Temperature 2 sensor is mounted

to the coolant manifold.”

NOTES


NOTES


NOTESNOTES

Module 4: Fuel System 25

Fuel System

Overview

The 2011 MaxxForce® 15 engine features a high-pressure common rail fuel system. This fuel system uses the following components: a remote-mounted primary filter, a remote-mounted primer pump, an engine mounted filter, low-pressure and high-pressure pumps, a high-pressure rail, high pressure lines and pipes and injectors.

The low-pressure pump draws fuel through the remote-mounted, 10 micron filter and primer pump. Fuel enters the low pressure pump, passing through to the internal pressure regulator.

Fuel then flows to the engine mounted filter module and passes through a 4 micron element.

Fuel passes through the filter and flows to the high-pressure pump, and the aftertreatment metering unit.

Fuel is also supplied to the cold start assist solenoid. The solenoid receives fuel from a port on the top of the filter module.

Module 4

“The low-pressure pump draws fuel through the remote-mounted filter and primer pump.”


Operation of the cold start system will be covered in air management.

The high-pressure pump delivers fuel through two high pressure lines to the rail where fuel is stored until it is used by the injectors. From the rail, individual high-pressure lines deliver fuel to the pressure pipes. The pressure pipes connect the fuel lines to the injectors.

Fuel returned from the injectors, the pressure limiting valve, the fuel filter module, and the high pressure pump merges into one line and returns to the fuel tank. will either pass through the remote filter assembly, or return directly to the tank.

Remote Mounted Fuel Filter

There are several types of remotely mounted fuel filter modules available. All modules feature a serviceable 10 micron filter and a water-in-fuel sensor.

The remote filter module can be heated through several different methods: utilizing the heat from the engine’s return fuel, using a 12 volt DC pre-heater, or through the use of a 120 volt AC pre-heater.

Depending on which module is installed, the primer pump will either

“All fuel filter modules feature a serviceable 10

micron filter.”


be integrated into the filter module, or mounted remotely.

Low-pressure & High-Pressure Pump

The low-pressure pump is mounted on the back of the high–pressure pump.

The low-pressure pump is internally regulated with an output of approximately 72-150 psi, or 5 to 10 bar.

This pump is not serviceable and must be replaced as an assembly.

The high-pressure pump is driven by the gear train. When looking at the engine from the flywheel, the high pressure pump rotates clockwise. Because of this, the pump is not interchangeable with any other application.

During operation, the pump increases the fuel pressure in the common rail from 12,574 psi, or 867 bar, at idle, to a maximum of 31,900 psi, or 2,200 bar, when at full load and rated speed.

The fuel pressure control valve is mounted on the rear of the pump. The ECM uses a pulse width modulated signal on the ground side of the circuit to regulate rail pressure.

“The high-pressure pump is driven by the gear train.”


An increase in duty cycle results in a lower pressure, while a decrease in duty cycle results in a higher pressure.

High-Pressure Fuel Lines & Pipes

The high-pressure fuel rail is mounted to the cylinder head and contains the pressure limiting valve and the fuel rail pressure sensor.

The pressure limiting valve, or PLV is located at the rear of the high-pressure rail. This valve relieves the pressure in the rail if it exceeds 37,709 psi, or 2,600 bar.

When this valve opens, excess fuel is returned back to the tank, limiting system pressure to approximately 14,503 psi, or 1,000 bar. The valve closes after the engine is shut down and the system pressure drops.

The Fuel Rail Pressure, or FRP, sensor is located at the front of the rail.

Both the pressure sensor and limiting valve are serviceable.

Injector Quantity Correction

2011 MaxxForce® 15 engines feature Injector Quantity Correction. Quantity Correction enables the

To avoid the risk of death or personal injury to yourself or other shop personnel, follow the proper procedure to relieve pressure before opening the fuel system for service. Refer to the Diagnostic Manual on ISIS® for proper procedures to relieve the pressure.

Warning!

Both the high-pressure lines and pressure pipes are one-time use only. Refer to the Service Manual on ISIS® for proper replacement procedures and torque sequence.

Warning!


ECM to maintain precise control of each injector. This feature requires programming of the ECM when replacing an injector.

To program the ECM after replacing an injector, the technician must enter the following information into ServiceMaxx®.

The Injector Quantity Adjustment code, located on the top portion of the injector, and cylinder placement of the new injector.

Fuel System Sensors

The fuel system is monitored by the; water-In-Fuel sensor, Fuel Delivery Pressure sensor and the Fuel Rail Pressure sensor.

The water-in-fuel sensor is located in the remote mounted filter. This sensor monitors the water level in the filter housing. If the water level is high, a lamp in the instrument panel will illuminate.

The fuel delivery pressure sensor is located on the engine mounted filter module. This sensor measures pressure on the non-filtered side of the supply system.

The Fuel Rail Pressure sensor is located at the front of the rail. The

“The water-in-fuel sensor is located in the remote mounted filter.”


3-wire micro strain-gage sensor monitors the pressure in the rail.

The ECM uses this input to help calculate the signals to the fuel pressure control valve.

This concludes the Fuel System.

“The ECM uses this input to help

calculate the signals to the fuel pressure

control valve.”

NOTES


NOTES


NOTESNOTES

Module 5: Air Management System 33

Air Management System

Overview

The MaxxForce® 15 air management system is divided into three subsystems: air induction, exhaust gas recirculation, and crankcase ventilation.

The main engine mounted components include a dual turbocharger assembly, a low-pressure charge-air-cooler, a two-stage EGR cooler, and a crankcase breather.

The low-pressure turbo draws air through the air filter and directs it to the low-pressure charge-air-cooler.

Charge air is then cooled and directed to the high-pressure turbo.

The high-pressure turbo compresses the air and directs it to the chassis-mounted high pressure charge-air-cooler.

Cooled air then flows through the throttle valve and into the mixer housing. The mixer housing directs the charge-air into the intake manifold.

Exhaust exits the manifold and enters the high-pressure turbine. The high-pressure turbine outlet is connected directly to the low-pressure turbine

Module 5

“The mixer housing directs the charge-air into the intake manifold.”


inlet. After passing through the low-pressure turbine, exhaust enters the turbo downpipe.

Some exhaust gas from the manifold is diverted to the EGR valve. If the valve is open, exhaust passes through the EGR cooler and flows through the crossover tube to the mixer housing. The mixer blends cooled exhaust gases with charge air.

Gases from the crankcase enter the breather module where oil is separated from the gases.

The oil is returned to the crankcase and the gases exit through the road draft tube.

The air management system is monitored by the ECM using the following twelve sensors: Charge Air Cooler Outlet Temperature EGR Outlet Temperature, Intake Manifold Pressure, Intake Manifold Temperature, Engine Throttle Valve Position, Crankcase pressure, Turbocharger 1 Turbine Outlet Pressure, Turbocharger 2 Compressor Inlet Sensor, Mass Airflow, EGR Valve Position, Oxygen Sensor and Ambient Air Temperature.

The inputs from these sensors are used to monitor the air management system.

“Some exhaust gas from the manifold is diverted to the

EGR valve.”


Air Induction

This engine uses dual turbochargers. Both turbos are mounted on the right side of the engine with the high pressure turbo located above the low pressure turbo.

Each turbo has a wastegate in the turbine housing. The wastegate diverts some of the exhaust flow away from the turbine wheel. Each wastegate is operated by a separate pneumatic actuator. If a wastegate is closed, all of the exhaust enters the turbine. If the wastegate is open, some exhaust bypasses the turbine.

The air control valve is mounted on the right front of the engine. This valve uses regulated air pressure, such as vehicle air, to control the wastegate actuators.

The air control valve contains the following ports: air supply, two vent ports turbocharger 2 wastegate control, turbocharger 1 turbine outlet pressure, and turbocharger 1 wastegate control.

The control valve requires a minimum of 90 psi to operate.

An internal pressure regulator reduces required pressure down to 25 to 45psi for the two wastegate actuators.

“Each turbo has a wastegate in the turbine housing.”

“The control valve requires a minimum of 90 psi to operate.”


When the ECM commands the control valve to open a wastegate, the vent port is closed, and air pressure is supplied to the actuator. This action overcomes an internal actuator spring and the wastegate is forced open.

When the ECM wants the wastegate closed, the air control valve vents the actuator air pressure to the atmosphere and the actuator spring forces the wastegate to close.

The turbocharger 1 turbine outlet pressure sensor is within the air control valve assembly.

Steel tubing connects the sensor to a port in the turbo down pipe. This sensor is used to measure exhaust pressure between the low pressure turbo and the engine mounted diesel oxidation catalyst.

Charge Air Coolers

The Low-Pressure Charge-Air-Cooler, or LP-CAC, is an air–to-water intercooler. The LP-CAC is located on the right side of the crankcase. The cooler reduces the temperature of charge air entering the high-pressure turbo.

The LP-CAC inlet uses a rubberized pipe connector. Lubricate the rubber

“When the ECM commands the

control valve to open a wastegate,

the vent port is closed.”

“The LP-CAC is located on the

right side of the crankcase.”


connectors with petroleum jelly during assembly. The LP-CAC outlet uses an O-ring seal at the outlet tube joint. Make sure the O-ring is seated properly during assembly.

The High-Pressure Charge-Air-Cooler, or HP-CAC, is an air-to-air cooler. The HP-CAC is mounted on the cooling module. Charge air from the turbo passes through the cooler before entering the mixer housing.

Air Induction Sensors

The air induction sub-system uses the following sensors: Intake Manifold Temperature, Mass Airflow, Turbocharger 2 Compressor Inlet Sensor, Charge Air Cooler Outlet Temp, Intake Manifold Pressure and the Ambient Air Temperature.

The Ambient Air Temperature sensor is a remotely mounted sensor that measures the air temperature. The location of this sensor varies with application.

The Mass Air Flow sensor is located in the low-pressure turbo inlet duct. The airflow measurement from this sensor is used to aid in the calculation of fuel injection quantity.

“The HP-CAC is mounted on the cooling module.”

“The Mass Air Flow sensor is located in the low-pressure turbo inlet duct.”


The Turbocharger 2 Compressor Inlet Sensor is located on the back of the low-pressure compressor outlet tube. The sensor is a combined sensor used to measure both the temperature and pressure of the charge air entering the LP-CAC.

The Intake Manifold Pressure sensor is located in the mixer housing after the Engine Throttle Valve.

The Intake Manifold Temperature sensor, or IMT, is located on the integrated intake manifold. This sensor measures the temperature of charge-air after it has been mixed with the cooled exhaust gases.

The Charge Air Cooler Outlet Temperature sensor is located on the mixing duct. This sensor measures the temperature of the air after it passes through the charge air cooler.

Exhaust Gas Recirculation

The Exhaust Gas Recirculation system, or EGR, features an electronic EGR valve,

an EGR cooler, Engine Throttle Valve, and several sensors.

The EGR valve assembly is located at the rear of the EGR cooler. The

“The Charge Air Cooler Outlet Temperature

sensor is located on the

mixing duct.”


assembly consists of a motor, butterfly valve, and cooling passages. To increase its durability, engine coolant is routed through passages within the valve.

The Engine Throttle Valve, or ETV, is located on the mixer housing. The ETV consists of a motor and a butterfly valve. The ECM controlled motor is used to position the valve.

When EGR flow is required, the ECM commands the EGR valve open.

Exhaust then flows through the cooler and the cross over tube to the mixer housing where it’s mixed with intake air.

If increased EGR flow is required, the throttle valve is commanded closed.

Closing the valve restricts intake air allowing the engine to pull additional EGR through the system.

EGR System Sensors

EGR operation primarily uses these sensors: EGR Valve Position, EGR Temperature, Engine Throttle Valve Position, Coolant Temperature 2, Intake Manifold Temperature and the Oxygen Sensor.

“When EGR flow is required, the ECM commands the EGR valve open.”


The EGR valve position sensor, or EGRP, is integrated into the valve assembly.

The ECM monitors valve position for proper EGR flow.

The EGR Temperature sensor, or EGRT, is located on the mixer housing. The ECM monitors the temperature of the exhaust gas entering the mixer housing.

The Engine Coolant Temperature 2 sensor, or ECT2, is located on the coolant manifold at the inlet of the LP-CAC. The ECM uses this sensor to assist in EGR gas temperature control by regulating the coolant control valve operation.

The oxygen sensor, or O2S, is located downstream of the turbocharger 1 turbine outlet. The O2S provides feedback to the ECM for proper positioning of the EGR valve.

The sensor’s heater element is activated after the engine coolant reaches 104° Fahrenheit, or 40° Celsius, and the exhaust gas temperature exceeds 212° Fahrenheit, or 100° Celsius, for more than 30 seconds.

The EGR system operates in open loop until the oxygen sensor is warm enough

“The ECM monitors the temperature

of the exhaust gas entering the mixer housing.”


to become active at approximately 1,400° Fahrenheit, or 760° Celsius.

Crankcase Ventilation

The crankcase breather is mounted on the left side of the engine near the valve cover. Crankcase gasses enter the filter housing through an external tube from the valve cover. An internal element filters the crankcase gases before exiting through the road draft tube. The gases exit the tube and the oil is returned to the crankcase.

A one way check valve is located at the bottom of the oil return tube. This valve prevents crankcase pressure from entering the breather through the oil return tube.

This concludes the Air Management System.

“A one way check valve is located at the bottom of the oil return tube.”

Module 6: Cold Start Assist 43

Cold Start Assist

MaxxForce® 15 engines feature Cold Start Assist. This system is designed to heat the intake air to aid in cold-start conditions.

This system consists of the: cold start relay, cold start fuel igniter, cold start fuel solenoid and the engine fuel filter module.

The cold start relay is used by the ECM to power the fuel igniter.

The igniter is mounted in the mixer housing and acts as a glow plug and a fuel injector.

The cold start solenoid controls fuel flow. When commanded by the ECM, the solenoid opens, allowing fuel to reach the igniter.

The engine fuel filter module contains an orifice and a pressure-relief valve. The orifice and regulator reduce fuel pressure at the igniter to approximately 7-12 psi.

Excess fuel pressure that passes by the relief valve is routed back to the tank through a return line.

When the operator turns the ignition Key-On, the wait-to-start lamp in the

Module 6

“The cold start relay is used by the ECM to power the fuel igniter.”


instrument panel illuminates.

Based on barometric pressure, coolant, oil, and the ambient air temperature, the ECM determines if the cold start assist is required.

If needed, the ECM activates the relay. The relay then powers the Fuel Igniter. Once the igniter is hot, the wait-to-start lamp begins to flash, telling the operator to crank the engine.

During cranking, the Fuel Solenoid opens and fuel contacts the igniter. Fuel is vaporized by the heat of the igniter and drawn into the cylinders. After the engine starts, the igniter and solenoid will remain powered while the wait-to-start lamp is flashing.

When the lamp is no longer illuminated, the relay and solenoid are de-activated.

This concludes the Cold Start Assist System.

“Once the igniter is hot, the wait-

to-start lamp begins flashing.”

NOTES

Module 6: Cold Start Assist 45

NOTES


NOTESNOTES

Module 7: Aftertreatment System 47

Aftertreatment System

Overview

The aftertreatment system is designed to capture and reduce soot in the exhaust. This system has components both mounted on and off the engine.

Aftertreatment system components on the right side of the engine are the pre-diesel oxidation catalyst, and the aftertreatment injector.

Components on the left side are: the engine throttle valve, ECM, and the downstream injection metering unit.

Other components located remotely are: the diesel-oxidation-catalyst and the diesel particulate filter.

PDOC, DOC, & DPF

The Pre-Diesel Oxidation Catalyst, or PDOC, and the Diesel Oxidation Catalyst, or DOC, have a series of small passages through the catalyst.

As exhaust flows through the passages, any unburned fuel reacts with the catalyst. This reaction generates heat, increasing the temperature of the exhaust.

Module 7

“As exhaust flows through the passages, any unburned fuel reacts with the catalyst.”


The DPF is located in the exhaust system after the diesel oxidation catalyst. The DPF has a series of small passages through the filter.

Half of the passages are plugged at the inlet, the other half are plugged at the outlet. This allows the DPF to act as a filter to trap the soot.

Active & Stationary Strategies

Downstream Injection

During active and stationary regen, the ECM partially closes the engine throttle valve to restrict intake air. This results in an increase in exhaust temperature.

Another strategy used by the ECM during active and stationary regen is Down-Stream Injection, or DSI.

The components used for downstream injection are: the downstream metering unit, the fuel lines, and the aftertreatment fuel injector.

DSI adds fuel to the exhaust stream.

The fuel reacts with the PDOC & DOC catalysts, increasing the exhaust temperature to reduce soot in the DPF.

The ECM controls injection through the metering unit.

“Half the DPF passages are

plugged at the inlet, the other

half are plugged at the outlet.”

“DSI adds fuel to the exhaust

stream.”


The metering unit includes a shut off valve, doser valve, fuel inlet sensor, and fuel pressure 2 sensor.

To achieve injection, the ECM opens the fuel shutoff valve.

At the same time, the module uses a fuel inlet sensor to monitor the pressure and temperature of the fuel entering the metering unit.

The ECM signals the doser valve to open, and a specific amount of fuel enters the injector supply line.

Fuel pressure in the supply line causes a pintle in the injector to lift, allowing fuel to spray out of the injector nozzle into the exhaust stream.

When the dosing valve closes, pressure in the supply line decreases, and the pintle in the injector closes.

The module continuously monitors feedback from the fuel-pressure-2 sensor to verify that dosing is complete.

Exhaust Sensors

There are four exhaust sensors in the aftertreatment system; one differential pressure sensor and three temperature sensors.

“To achieve injection, the ECM opens the fuel shutoff valve.”

“When the dosing valve closes, pressure in the supply line decreases, and the pintle in the injector closes.”


The Exhaust Gas Differential Pressure sensor, or EGDP, is located on a bracket mounted to the DPF.

This sensor compares the inlet and the outlet pressures of the DPF and allows the ECM to determine the soot load.

When there is a high soot load, the pressure difference across the DPF is high.

The DOC inlet temperature sensor monitors the exhaust before the DOC.

This sensor allows the ECM to determine if the exhaust temperature is high enough to perform downstream injection.

The DOC outlet temperature sensor is located after the DOC.

The ECM uses this signal to determine if the PDOC and DOC are creating enough heat for regeneration.

The DPF outlet temperature sensor is located after the DPF.

The ECM compares the DPF and DOC outlet temperatures to determine if regeneration has occurred.

For an active regeneration to be successful, exhaust temperature must

“The ECM uses this signal to determine

if the PDOC and DOC are creating

enough heat for regeneration.”


be within the range of approximately 950 to 1,100° Fahrenheit, or 500 to 600° Celsius.

If the temperature is too high at the DPF outlet, the ECM limits downstream injection.

Stationary or Parked Regeneration

When the active regen strategies do not sufficiently reduce the soot load in the DPF, the ECM notifies the operator by illuminating a lamp on the instrument panel that stationary regen is needed.

Refer to the operator’s manual for the proper procedure to initiate a stationary regen.

During a stationary regen, the ECM controls engine speed, partially closes the engine throttle valve, and injects fuel into the exhaust.

With the increased heat, the soot load in the DPF will be reduced.

This concludes the Aftertreatment System.

“When active regen strategies do not sufficiently reduce the soot load, the ECM notifies the operator.”


NOTES

Conclusion 53

Conclusion

This concludes the 2011 MaxxForce® 15 Engine Training for Technicians program.

Thanks for your participation.

You are now required to take a post-test.


NOTES

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