English 966h and 972h Whell Loaders (2)

SERV1815August 2006

TECHNICAL PRESENTATION

966H AND 972H WHEEL LOADERS

Service Training Meeting Guide(STMG)

GLOBAL SERVICE LEARNING

966H AND 972H WHEEL LOADERSMEETING GUIDE 815 VISUALS AND SCRIPT

AUDIENCE

Level II - Service personnel who understands the principles of machine system operation,diagnostic equipment, and procedures for testing and adjusting.

CONTENT

This presentation describes the location of the basic components on the engine, and theoperation of the power train, implement, steering, and brake systems for the 966H and 972HWheel Loader. This presentation may be used for self-paced and self-directed training.

OBJECTIVESAfter learning the information in this presentation, the technician will be able to:

1. Locate and identify the major components in the C11 and C13 ACERT engine, powertrain, implement, steering, and brake systems;

2. Explain the operation of each component in the power train, implement, steering, andbrake systems; and

3. Trace the flow of oil through the power train, implement, steering, and brake systems.

GLOBAL REFERENCES

966H Wheel Loader Specalog AEHQ5657972H Wheel Loader Specalog AEHQ5658966H and 972H Wheel Loader Service Manual RENR8840966H Wheel Loader Parts Manual (A6D) SEBP3743972H Wheel Loader Parts Manual (A7D) SEBP3744966H Wheel Loader Parts Manual (A6G) SEBP3747972H Wheel Loader Parts Manual (A7G) SEBP3748NPI Vol. 9, No. 1 "966H and 972H Wheel Loader SERV7105TIM "966G Series II Wheel Loader Power Train" SERV2739TIM "972G Series II Wheel Loader Power Train" Updated SERV2658TIM "972G Series II Wheel Loader Command Control Steering" Update SERV2660TIM "972G Series II Wheel Loader Steering and Braking" Updated SERV2659

Estimated Time: 8 HourIllustrations: 194Form: SERV1815Date: 08/06

2006 Caterpillar Inc.

TABLE OF CONTENTS

INTRODUCTION ..................................................................................................................7Component Location.........................................................................................................8

ENGINE................................................................................................................................10Engine Electrical Block Diagram ...................................................................................11Engine Right Side ...........................................................................................................14Engine Left Side .............................................................................................................15Crankshaft Speed Timing Sensor ...................................................................................16Engine Speed/Timing Calibration Port...........................................................................19Fuel System.....................................................................................................................20Fuel Transfer Pump.........................................................................................................22Power Derate...................................................................................................................23Fuel Filter Sensors ..........................................................................................................24Fuel Temperature Derate ................................................................................................26High Fuel Filter Restriction Derates...............................................................................27Engine Inlet Air System..................................................................................................28Turbo Inlet Pressure Sensor............................................................................................30Air Inlet Restriction Derate ............................................................................................31Oil Pressure Sensor.........................................................................................................32Low Oil Pressure ............................................................................................................33Coolant Temperature Sensor...........................................................................................34High Coolant Temperature Derate..................................................................................35Intake Manifold Sensors .................................................................................................36Intake Manifold Air Temperature Sensor Derate ...........................................................37Virtual Exhaust Temperature Derate ..............................................................................38

POWER TRAIN ...................................................................................................................43Power Train Electrical System .......................................................................................46Engine Start Switch and Diagnostic Service Tool Connector ........................................49Transmission Shift Lever................................................................................................50Transmission Shift Control .............................................................................................51Transmission Oil Temperature Sensor............................................................................57Left Brake Pedal Position Sensor ...................................................................................58Implement Pod Downshift Switch and Remote F-N-R Switch .....................................59Parking Brake Pressure Switch.......................................................................................60Back-up Alarm................................................................................................................63Warning Panel - Left Side ..............................................................................................64Implement Control Valve - With Ride Control ..............................................................65Secondary Steering Intermediate Relay..........................................................................66Engine Start Relay ..........................................................................................................67Transmission Hydraulic System - NEUTRAL...............................................................68Transmission Modulating Valve - No Commanded Signal ............................................76Transmission Modulating Valve - Commanded Signal Below Maximum.....................77Transmission Modulating Valve - Commanded Signal At Maximum ...........................79Transmission Modulating Valve - Solenoids..................................................................81

SERV1815 - 3 - Text Reference08/06

TABLE OF CONTENTS (continued)

Transmission Relief Valve ..............................................................................................83Variable Shift Control .....................................................................................................89Integrated Brake System.................................................................................................90Left Brake Pedal Actions................................................................................................91Speed Limiter..................................................................................................................93

IMPLEMENT ELECTROHYDRAULIC SYSTEM............................................................94Implement Electronic Control System ...........................................................................95Implement Control Levers............................................................................................102Fine Modulation............................................................................................................104Autodig Control Arrangement ......................................................................................106Implement Hydraulic System - HOLD.........................................................................110Tilt Control Valve - HOLD...........................................................................................112Implement Hydraulic System - DUMP ........................................................................113Pressure Compensator Valve - HOLD..........................................................................114Load Check Operation ..................................................................................................115Pressure Compensator Operation..................................................................................116Implement Hydraulic System - DUMP ........................................................................120Implement Hydraulic System - RAISE ........................................................................122Implement Hydraulic System - FLOAT .......................................................................124Implement Hydraulic System - Tilt Back and Raise ....................................................126Implement Hydraulic System - RIDE CONTROL AUTO...........................................128Ride Control Valve - Auto/Travel Below 9.7 km/h (6 mph)........................................130Ride Control Valve - Auto/Travel More than 9.7 km/h (6 mph)..................................131Implement Pump and Pump Control Valve ..................................................................134Pump Control Valve - Engine Off ................................................................................135Pump Control Valve - Standby .....................................................................................137Pump Control Valve - Upstroke....................................................................................138Pump Control Valve - Constant Flow Demand ............................................................139Pump Control Valve - Maximum System Pressure ......................................................140Pump Control Valve - Maximum System Pressure with Added Flow Demand ..........141Implement Valve ...........................................................................................................142Differential Pressure Relief Valve ................................................................................143Pressure Reducing Valve ..............................................................................................144Pressure Reducing Valve - Above the Adjusted Pressure ............................................145Load Sense Pressure Tap ..............................................................................................146Signal Duplication Valve ..............................................................................................150Signal Relief Valve - Below the Adjusted Pressure Setting.........................................151Signal Relief Valve - Above the Adjusted Pressure Setting.........................................152Line Relief Valve- Closed.............................................................................................153

STEERING SYSTEM ........................................................................................................158Steering Pump...............................................................................................................162Steering Pump with the Engine OFF............................................................................163Low Pressure Standby ..................................................................................................164


TABLE OF CONTENTS (continued)

Pump Upstroke .............................................................................................................165Pump Destroke..............................................................................................................166High Pressure Stall .......................................................................................................167Steering Control Valve..................................................................................................168Steering Neutralizer Valves ..........................................................................................169Steering Neutralizer Valve ............................................................................................170Steering System Schematic...........................................................................................171Steering System - Gradual Left Turn............................................................................173Steering System - Full Left Turn - Steering Neutralized .............................................174Secondary Steering ......................................................................................................176Steering Pilot Valve ......................................................................................................183Steering Pilot Valve - No Turn .....................................................................................185Steering Pilot Valve - Right Turn .................................................................................186Steering System - Command Control Steering ............................................................188

BRAKE AND HYDRAULIC FAN SYSTEM COMPONENTS.......................................191Brake and Hydraulic Fan System - Cut In and Minimum Fan Speed .........................193Brake and Hydraulic Fan System - Minimum Fan Speed at Cut Out..........................194Brake and Hydraulic Fan System - Maximum Fan Speed at Cut Out.........................196Brake and Hydraulic Fan Pump ...................................................................................203Service Brake Valve - Low Pressure Standby ..............................................................205Brake and Hydraulic Fan Pump - Upstroke .................................................................207Accumulator Charge Vale and Hydraulic Fan Solenoid...............................................211Service Brake Valve......................................................................................................213Service Brake Valve - Not Activated............................................................................216Service Brake Valve - Activated..................................................................................217

CATERPILLAR MONITORING SYSTEM ......................................................................219Fuel Level Sender .........................................................................................................220Hydraulic Oil Temperature Sensor ...............................................................................222Brake Pressure Switch ..................................................................................................223Axle Oil Temperature Sensors......................................................................................224Filter Bypass Switch in the Right Side Service Bay....................................................225Torque Converter Outlet Temperature Sensor..............................................................227Electrical System ..........................................................................................................228Action Alarm.................................................................................................................230Engine Tachometer .......................................................................................................231

CONCLUSION...................................................................................................................232

HYDRAULIC SCHEMATIC COLOR CODE...................................................................233


NOTES


INTRODUCTION

This presentation discusses the component locations and systems operation of the 966H and972H Wheel Loader. Basic engine and machine component operation will be discussed. Thenew C11 and the C13 ACERT engines, the power train, proportional priority, pressurecompensated implement hydraulics, the steering, and braking system operation will be covered.

The 966H and 972H are medium wheel loaders in the Caterpillar product line. The serialnumber prefix for the 966H is A6D Aurora built (A6G Gosselies, A6J Sagami) and the serialnumber for the 972H Wheel Loader is A7D Aurora built (A7G Gosselies, A7J Sagami).

The 966H operating weight is approximately 23,100 Kg (51,000 lbs) and the 972H operatingweight is approximately 25,000 Kg (55,400 lbs).

The color codes used for hydraulic oil throughout this presentation are:

Red - System or high pressure

Red and White Stripes - First reduced pressure

Orange - Pilot pressure

Blue - Blocked oil

Green - Tank or return oil

Yellow - Active component

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966H AND 972H WHEEL LOADERS

2006 Caterpillar Inc.

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Component Location

This illustration shows the basic component locations on the 966H and 972H. The componentlocations on the 966H and 972H are basically the same as in the G series II Wheel Loaders.

Power for the 966H is supplied by the C11 ACERT and the power for the 972H is suppliedby the C13 ACERT engine. Power flows from the engine to the torque converter, to theElectronic Clutch Pressure Controlled (ECPC) transmission, through the output transfer gear tofront and rear drive shafts. From the drive shafts, power flows to the bevel gears in thedifferentials, and through the axles.

The wheel loader is equipped with a steering pump, steering control valve, and steeringcylinders. Also, the machine is equipped with an electrohydraulic implement control with avariable displacement implement piston pump supplying oil to the 3PC hydraulic valve locatedin the loader frame.

The machine may be equipped with an optional electric secondary steering pump that isinstalled inside the rear frame.


C7Engine

Transmission

FrontFinal Drive

RearFinal Drive

RearDrive Shaft

TorqueConverter

FrontDrive Shaft

ParkingBrake

HydraulicTank

EngineECM

Radiatorand ATAAC

ImplementControl Valve

TiltCylinder

LiftCylinder

Tilt PositionSensor

LiftPosition Sensor

ImplementControl Levers

Fan Pump

Power Train andImplement ECM

SteeringValve

Implement andSteering Pumps

FanMotor

SteeringCylinder

Air ConditionerCondenser

Hydraulic FanCooler

AccumulatorCharging Valve

Steering ControlValve

WHEEL LOADER COMPONENTS

Electrical Components Hydraulic Components Power Train ComponentsEngine Components

The wheel loader is equipped with an on demand hydraulic fan system and brake system thatshare a common variable displacement piston pump and accumulator charging valve. Themachine uses a priority valve with the brake system having priority over the hydraulic fansystem. The brake system includes the front and the rear service brakes. The parking brake isspring applied, and hydraulically released.


ENGINE

The C11 ACERT and C13 ACERT engines utilize the A4 Electronic Control Module(ECM) engine control and is equipped with an Air to Air Aftercooler (ATTAC) intake aircooling system. The C11 engine is rated at 175 kW (235 net horsepower). The C13 engine israted at 198 kW (265 horsepower). The C11 and C13 engines are electronically configured toprovide constant net horsepower through the operating ranges. Constant net horsepowerautomatically compensates for any parasitic loads, allowing the operator to maintain a constantlevel of productivity.

The Engine ECM utilizes the ADEM IV to control the fuel injector solenoid and to monitor fuelinjection. The fuel is delivered through a Mechanical Electric Unit Injection (MEUI) system.

ACERT Technology provides an advanced electronic control, a precision fuel delivery, andrefined air management.

The C11 engine is an in-line six-cylinder arrangement with a displacement of 11.1 L. The C13engine is also an inline six-cylinder arrangement with a displacement of 12.5 L.

The C11 and C13 ACERT engines meet all US Environmental Protection Agency (EPA) TierIII Emission Regulations for North America and Stage IIIa European Emission Regulations.

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Engine Electrical Block Diagram

This block diagram of the engine electrical system shows the components that are mounted onthe engine which provide input signals to and receive output signals from the Engine ElectronicControl Module (ECM).

Based on the input signals, the Engine ECM energizes the injector solenoid valves to controlfuel delivery to the engine, and energizes the cooling fan proportional solenoid valve to adjustpressure to the cooling fan clutch.

The two machine interface connectors provide electrical connections from the engine to themachine including the Cat Data Link.

Some of the components connected to the Engine ECM through the machine interfaceconnectors are: the throttle pedal position sensor, the right brake pedal switch, the ether startcontrol solenoid, and the ground level shutdown switch.


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Input Components:

Camshaft speed timing sensor - The speed timing sensor sends a fixed voltage level signal tothe Engine ECM in order to determine the engine speed, direction, and timing.

Crankshaft speed timing sensor - The speed timing sensor sends a fixed voltage level signalto the Engine ECM in order to determine the engine speed, direction, and timing.

Atmospheric pressure sensor - This sensor is an input to the Engine ECM and is used as areference for air filter restriction. Also, the sensor is used to supply information to the EngineECM during operation at high altitude.

Turbo inlet pressure sensor - This sensor is an input to the Engine ECM to supplyinformation about the air restriction before the turbocharger.

Intake manifold air temperature sensor - This sensor supplies air temperature data at theintake manifold to the Engine ECM.

Fuel differential pressure switch - This switch relays information to the ECM that the fuelpressure at the output of the filter base is restricted in comparison to the inlet pressure.

Coolant temperature sensor - This sensor monitors the temperature of the fluid in the coolantsystem. The coolant flow switch mounts in the coolant passage near the engine coolant pump.When the coolant is flowing past the switch the paddle moves and closes the switch contacts.The Engine ECM alerts the operator when there is no coolant flow while the engine is running.

Fuel temperature sensor - This sensor sends fuel temperature data to the Engine ECM.

Engine oil pressure sensor - This sensor is an input to the Engine ECM to supply aninformation warning for low oil pressure, engine derates for low oil pressure, or a logged eventread by ET.

Throttle pedal position sensor - This sensor sends the throttle position to the Engine ECM inorder to increase or decrease the fuel supply to the injector.

Auto reversing fan switch - This switch is an operator input to the Engine ECM. The operatorcan manually enable the reversing solenoid valve and change the direction of oil flow throughthe hydraulic fan motor.

Key switch ON (+B) - The Key On input to the Engine ECM enables the ECM for operationand is recognized by any ECM on the machine.

Ground level shutdown switch - This switch is an input to the Engine ECM. This inputdisables fuel injection when the engine is running or at engine start-up.

Intake manifold air pressure sensor - This sensor is an input to the Engine ECM to supplyinformation about the air pressure into the intake manifold.


Output Components:

+5 Volt - Regulated supply voltage for the sensor inputs to the Engine ECM.

Throttle sensor voltage - Voltage supply for the throttle position sensor.

Analog sensor voltage - Analog voltage for the turbo inlet pressure sensor.

Either ON solenoid valve - Solenoid valve used to apply ether in order to start the engine incold weather.

Auto reversing fan solenoid valve - This solenoid valve is used in order to reverse the oil flowoil through the hydraulic fan motor..

Demand fan solenoid valve - Proportional solenoid valve that controls the signal pressure tothe brake and hydraulic fan pump in order to meet the varying cooling requirements of themachine.

Air filter restriction indicator - This indicator illuminates in case of a restriction in the inletair system.

Ether On indicator - This indicator illuminates when the ether solenoid valve is initiated.


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Engine Right Side

This view shows the right side of the engine accessed from the right side of the machine.

Components which can be seen are:

- Alternator (1)

- Electric fuel priming pump (2)

- Secondary fuel filter (3)

- Air inlet (4)

- Fuel transfer pump (5)

- Brake and hydraulic fan pump (6)

- Brake accumulator charging valve (7)

- Engine ECM (8)

- Cam speed sensor and Atmospheric pressure sensor (9)

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Engine Left Side

This view shows the left side of the engine accessed from the left side of the machine.

Components which can be seen are:

- Air inlet (with turbo inlet pressure sensor) (1)

- Turbocharger (wastegated) (2)

- Coolant regulator housing (3)

- Transmission cooler (coolant-to-oil) (4)

- Engine coolant pump (5)

- Engine oil cooler (coolant-to-oil) (6)

- Engine starter (7)

- Engine oil filter (8)


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Crankshaft Speed Timing Sensor

The crankshaft speed timing sensor (1) is located in the front of the engine at the rear of themachine. The crankshaft sensor is the primary speed sensor reporting to the Engine ECM withthe engine speed and position of the crankshaft. The speed sensor detects the reference forengine speed and timing from a unique pattern on the respective gear. Normally the crankshaftspeed timing sensor identifies the timing during starting and determines when the No. 1cylinder is at the top of the stroke. When the timing is established, the crankshaft timing sensoris used to relay the engine speed and the camshaft sensor is ignored. If the engine is runningand the signal from the crankshaft is lost, a slight change in performance is noticed duringchange over to the camshaft sensor.

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If the signal from the crankshaft speed timing sensor is lost or intermittent, normally a CID 0190 FMI 08 Engine Speed Abnormal will be logged and can be viewed throughCaterpillar ET.

Also, the engine speed is shared with the Power Train ECM.

Also shown is the brake and hydraulic fan pump (2).


The atmospheric pressure sensor (1) is located on the left side of the machine on the engine.The Engine ECM uses the sensor as a reference for air filter restriction and derating the engineunder certain parameters. All pressure sensors in the system measure absolute pressure and,therefore, require the atmospheric pressure sensor to calculate gauge pressures.

The atmospheric pressure sensor is one of the many sensors that require a regulated 5.0 VDCfor the sensor supply voltage. The atmospheric pressure sensor outputs a variable DC voltagesignal.

The Camshaft speed timing sensor (2) is located below the atmospheric pressure sensor. Undernormal operation, the camshaft speed timing sensor determines the No. 1 compression timingprior to the engine starting. If the camshaft sensor is lost, a CID 342 MID 08 Secondary enginespeed signals abnormal code is active and the crankshaft sensor will time the engine with anextended starting time. The engine will run rough until the Engine ECM determines the properfiring order using the crankshaft sensor only. In the case that the signal from both engine speedsensors is lost, the engine will not start. During a running condition, the engine will shutdown.

The sensor serves as a back-up for the crankshaft speed timing sensor. If the crankshaft speedtiming sensor fails, the camshaft speed timing sensor allows for continuous operation.

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Engine Speed/Timing Calibration Port

The speed/timing calibration port is located on the right side of the machine. The Engine ECM (1) has the ability to calibrate the mechanical differences between the Top Center(TC) of the crankshaft and the timing gear on the camshaft. A magnetic transducer signals theTC of the crankshaft to the ECM when the notch (2) on a counterweight passes by thetransducer (not shown). The speed/timing sensor signals the TC of the timing gear to theEngine ECM. Any offset between the TC of the crankshaft and the TC of the timing gear isstored into the memory of the Engine ECM.

Remove the plug (3) in order to install the timing probe.

NOTE: For additional information in troubleshooting the engine, refer to the ServiceManual module Troubleshooting "C11 and C13 Engines for Caterpillar Built Machines"(RENR9318) "Engine Speed/Timing Sensor - Calibrate.


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Fuel System

Fuel is drawn from the fuel tank through the primary fuel filter and water separator by a gear-type fuel transfer pump. The fuel transfer pump then directs the fuel through thesecondary fuel filter.

The fuel then flows to the cylinder head. The fuel enters the cylinder head and flows into thefuel gallery, where it is made available to each of the six MEUI fuel injectors. Any excess fuelnot injected leaves the cylinder head and flows back to the secondary fuel filter. Then, theexcess fuel flows past the fuel pressure regulator.

The fuel pressure regulator is a check valve that is installed in the secondary fuel filter. Thefuel pressure regulator maintains fuel system pressure between the fuel transfer pump and thefuel pressure regulator.

From the fuel pressure regulator, the excess fuel flow returns to the fuel tank. The ratio of fuelused for combustion and fuel returned to tank is approximately 3:1 (i.e. four times the volumerequired for combustion is supplied to the system for combustion and injector coolingpurposes).


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A differential pressure switch is installed in the secondary fuel filter base and will alert theoperator of a fuel filter restriction. The differential pressure switch compares the filter inletpressure to the filter outlet pressure. When the difference in the inlet and outlet pressurescauses the switch to activate, the Engine ECM will signal the Caterpillar Monitoring System towarn the operator the fuel flow is probably restricted.

A fuel temperature sensor is installed in the secondary fuel filter base and will signal theEngine ECM of a high fuel temperature. The effect of high fuel temperature is an enginederate. The fuel system will derate to 12.5% at 91 C (196 F) percent to a maximum derate of25%.

A fuel pressure sensor is installed in the secondary fuel filter base and will signal the EngineECM of a high fuel pressure. If the fuel pressure exceeds a pressure of 758 kPa (110 psi) theEngine ECM will log a E096 code.

In the case of a logged high fuel pressure Event, check the following Fuel System'sComponents:

- Inspect the fuel transfer pump pressure relief valve that is in the body of fuel transferpump. Check for damage to the spring or to the valve assembly.

- Verify that the pressure regulating valve in the fuel filter manifold is operating correctly.Check for damage or for dirt in the valve assembly.

- Check the return line from the fuel filter base to the fuel tank for damage or collapse.


Fuel Transfer Pump

The fuel transfer pump is a gear pump that is located near the balancer at the front of the engineand the rear of the machine. The fuel transfer pump is driven by the front gear train. Fuel isdrawn from the primary fuel filter and water separator by the fuel transfer pump and then, it isdirected to the secondary fuel filter.

The fuel transfer pump incorporates a check valve. The check valve allows fuel to flow aroundthe gears of the pump when the fuel system is primed. A relief valve (not shown) is alsoinstalled in the fuel transfer pump. The relief valve limits the maximum fuel pressure in thefuel system.

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Power Derate

The illustration above defines the power derate in relation to the rated torque map and thedefault torque map. The power derate is a percentage reduction from the rated power at a givenengine speed toward the default map at the same rpm.

Power is unchanged until the requested power exceeds the derated level. The maximum powerduring a derate is calculated as:

Maximum Power Output = Rated Power - (Rated Power - Default Power) * Derate Percentage

For example, if the engine has a maximum rated power of 500 hp and a 100 hp default torquemap with a 50% derate, the engine will have 300 hp output power. If 250 hp was needed, thenthe operator will not notice any change. If however, 400 hp was needed, there would be only300 hp available due to derates.

300 hp = 500 hp - (500 hp - 100 hp) X 50% (.50)


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Fuel Filter Sensors

The fuel system is equipped with two filters, a primary fuel filter/water separator (1) and asecondary filter (2).

The primary fuel filter is located on the right side of the machine. The primary filter contains awater separator which removes water from the fuel. Water in a high pressure fuel system cancause premature failure of the injector due to corrosion and lack of lubrication. Water shouldbe drained from the water separator daily, using the drain valve that is located at the bottom ofthe filter.

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The electric fuel priming pump (4) is integrated into the primary fuel filter base. The primingpump is activated by toggling the fuel priming pump switch (3). The fuel priming pump isused to fill the fuel filters with fuel after they have been replaced.

The priming pump will purge the air from the entire fuel system. To activate the fuel primingpump, the key start switch must be in the OFF position.

The fuel system is equipped with a secondary high efficiency fuel filter. The fuel regulator (5)is integrated into the secondary fuel filter base. The fuel pressure regulator regulates the theflow of fuel from the fuel gallery.

Also, installed on the base is a fuel differential pressure switch (7), a fuel pressure sensor (6)and a fuel temperature sensor (8).

The fuel differential pressure switch monitors the difference between the outlet fuel pressureand the inlet pressure. Fuel pressure exceeding 103 kPa (15 psi) will initiate a Level 1Warning. Then, after 4 hours the Engine ECM initiates a Level 2 Warning and an EngineDerate.

The fuel pressure sensor indicator of a fuel return or a pressure control problem. Excessivelyhigh pressure in the fuel system can cause problems for the injector.

A differential pressure switch is installed in the secondary fuel filter base and will alert theoperator of a fuel filter restriction. The differential pressure switch compares the filter inletpressure to the filter outlet pressure. When the difference in the inlet and outlet pressurescauses the switch to activate, the Engine ECM will signal the Caterpillar Monitoring System towarn the operator the fuel flow is probably restricted.

A fuel temperature sensor is installed in the secondary fuel filter base and will signal theEngine ECM of a high fuel temperature. The effect of high fuel temperature is an enginederate. The fuel system will derate to 12.5% at 91 C (196 F) percent to a maximum derate of25%.

A fuel pressure sensor is installed in the secondary fuel filter base and will signal the EngineECM of a high fuel pressure. If the fuel pressure exceeds a pressure of 758 kPa (110 psi) theEngine ECM will log a E096 code.

In the case of a logged high fuel pressure Event, check the following Fuel System Components:

- Inspect the fuel transfer pump pressure relief valve that is in the body of fuel transferpump. Check for damage to the spring or to the valve assembly.

- Verify that the pressure regulating valve in the fuel manifold is operating correctly. Checkfor damage or for dirt in the valve assembly.

- Check the return line from the fuel filter base to the fuel tank for damage or collapse.


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Fuel Temperature Derate

This illustration shows the graph for the warning and derates map for the fuel temperature.When the fuel temperature exceeds 90 C (194 F), the Engine ECM will activate a Level 1Warning. Also, the graph shows, as the fuel temperature increases to 91.0 C (196 F) a Level2 Warning will be initiated by the Engine ECM. At the same time, the engine will derate to12.5%. If the fuel temperature exceeds 92 C (198 F), the engine will be derated to 25%.

A fuel temperature sensor open circuit will derate the engine to 12.5%.

Excessive fuel temperature will cause injector wear.


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FUEL TEMPERATURE DERATE

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Level 1 Warning Level 2 Warning / Derates

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High Fuel Filter Restriction Derates

When the fuel differential pressure switch recognizes a fuel pressure of 103 kPa (15 psi) for 3minutes, the Engine ECM will initiate a Level 1 Warning.

When the fuel differential pressure switch recognizes 15 psi across the filter for 4 hours, theEngine ECM will initiate a Level 2 Warning. With the Level 2 Warning initiated a 17.5 %derate is applied to the engine. After 1 second, the Engine ECM will initiate a second derate of17.5%. The total derate will be 35%.

This feature will be disabled when the fuel temperature is below 30 C (86 F).


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FUEL FILTER RESTRICTION DERATETHE FUEL TEMP ABOVE 30 C (86 F)

AND PRESSURE ABOVE 110 kPa (15 psi)

TimeLevel 1Warning Level 2 Warning / Derates

Engine Inlet Air System

In the engine inlet air system, the air enters the compressor section of the turbocharger (4)through the air cleaner (2). The compressor directs the air through the ATAAC (3), the intakemanifold, and to the cylinder head.

Exhaust exits the cylinder head to the turbine housing. From the turbine housing, the turbinewheel directs the exhaust out of the turbo and out through the muffler (1).

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The C11 and C13 ACERT engines are equipped with a wastegate turbocharger whichprovides higher boost over a wide range, improving engine response and peak torque, as well asoutstanding low-end performance. All of the exhaust gases go from the exhaust manifoldthrough the turbocharger.

The exhaust gases enter the turbocharger and drive the turbine wheel. The exhaust gases exitthe turbocharger through the turbine wheel outlet (2) to the muffler. The turbine wheel isconnected by a shaft to the compressor wheel. The turbine wheel rotates the compressor wheelat very high speeds. The rotation of the compressor wheel pulls clean air through thecompressor housing air inlet (1). Then, the compressor wheel blades force air into the cylinderhead to the inlet valves. The increased amount of forced air enables the engine to be able toburn more fuel producing increased power. The engine can operate under low boost conditions.During a low boost condition, the canister closes the wastegate, allowing the turbocharger tooperate at maximum performance. Under high boost conditions, the wastegate opens. Theopen wastegate allows exhaust gases to bypass the turbine side of the turbocharger. The rpm ofthe turbocharger is limited by bypassing a portion of the exhaust gases around the turbinewheel.

NOTE: The wastegate calibration is preset at the factory.


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Turbo Inlet Pressure Sensor

The turbocharger inlet pressure sensor (arrow) is located in the tube that is between the air filtergroup and the inlet to the compressor housing.

The turbocharger inlet pressure sensor measures restriction of air flow through the air filters andthe inlet. Restriction of the air flow to the turbocharger will initiate a warning and enginederate.

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Air Inlet Restriction Derate

The turbo inlet pressure sensor measures the restriction of the air inlet that is flowing to theinlet of the compressor housing of the turbocharger. When the pressure difference between theturbo inlet pressure sensor and the atmospheric sensor read a difference of 9.0 KPa, theEngine ECM will derate the engine approximately 2%. The Engine ECM will then derate theengine 2% more for every 1 kPa difference up to 10%.

Typically, the atmospheric pressure sensor is 100 Kpa at sea level. As the air restrictionincreases, the difference will increase. The first derate will occur when the difference isapproximately (100 kpa minus 91 kpa.= 9 kpa).

If the air inlet restriction is 92.5 kPa (a pressure that is between 7.5 kPa and 9 kPa) for 10seconds, the Engine ECM will initiate a Level 1 Warning.

If the air restriction goes to the point that the turbo inlet pressure sensor sees a difference of91.0 kPa (a pressure that is 9.0 KPa) for 10 seconds, then the Level 2 Warning will occur andthe engine will go into the air inlet restriction derate.


0 2 4 6 8 10

12%

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4%

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0%

% D

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12 14 16

14%

16%

Air Restriction kPa Difference

AIR INLET RESTRICTION DERATE

Level 1Warning DeratesLevel 2 Warning /

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Oil Pressure Sensor

The engine oil pressure sensor (1) is located on the left side of the engine and the right side ofthe machine near the Engine ECM (2). The sensor monitors the pressure of the engine oil.

The engine oil pressure sensor is one of the many sensors that require a regulated 5.0 VDC forthe sensor supply voltage. The sensor outputs a variable DC voltage signal.

The Engine ECM will use the information supplied oil pressure sensor to output warning levelsto the Caterpillar Monitoring System and engine derates.


1

2

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Low Oil Pressure

This illustration shows a graph with the two different warning levels for low oil pressure.

When the oil pressure is below (154 kPa @ 1600 rpm) the blue line, the Cat Monitoring Systemwill enable the low oil pressure Level 1 Warning: Change machine operation or performmaintenance to the system.

When the oil pressure is below (104 kPa @ 1600 rpm) the red line, the Cat Monitoring Systemwill enable the low oil pressure Level 3 Warning: The operator should immediately perform asafe engine shutdown.

Also, with the Level 3 Warning, the Engine ECM initiates a 35% engine derate.

If the signal between the Engine ECM and the oil pressure sensor is lost or disabled, the EngineECM will initiate a low engine oil pressure Level 1 Warning.


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Coolant Temperature Sensor

The coolant temperature sensor (arrow) is installed at the right front corner of the engine, abovethe jacket water pump. The coolant temperature sensor monitors the temperature of the fluid inthe coolant system. The coolant temperature sensor information sent to the Engine ECM isused for Warning Levels that are sent to the Caterpillar Monitoring System and engine derates.


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High Coolant Temperature Derate

The coolant temperature sensor measures the temperature of the coolant.

When the temperature of the coolant exceeds 110 C (230 F), the Engine ECM will initiate aLevel 1 Warning.

When the temperature of the coolant exceeds 111 C (231 F), the Engine ECM will initiate aLevel 2 Warning. At 111 C (231 F) the Engine ECM will initiate a 25% derate. Refer to theillustration for the remainder of the high engine coolant temperature derates. At 100% derate,the engine available power will be approximately 50%.


110 116 116.5 117 117.5 118 118.5 119

120%

100%

80%

60%

40%

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0%

Coolant Temperature C

% D

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HIGH COOLANT TEMPERATURE DERATE

119.5

Level 1Warning Level 3 Warning / Derates

Intake Manifold Sensors

The upper illustration shows the intake manifold air pressure sensor (1), and the intakemanifold air temperature sensor.

The intake manifold air pressure sensor (1) is used to monitor intake manifold air pressure.

The intake manifold air temperature sensor (2) is used to monitor the air temperature flowinginto the intake manifold. The Engine ECM also uses the temperature sensor as one of the keytarget temperatures to control the fan speed in the hydraulic fan system. Also, the sensor isused as an input to the Engine ECM for the virtual exhaust temperature derate. Also shown isthe Engine ECM (3) and intake manifold (4).

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1

23

1

2

4

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Intake Manifold Air Temperature Sensor Derate

The intake manifold air temperature sensor measures the temperature of the air that is flowingto the intake manifold. The sensor is used to initiate warning levels and engine derates.

After the engine is running for at least 3 minutes and if the intake manifold air temperature goesabove 82 C (180 F), the Engine ECM will initiate a Level 1 Warning.

After the engine is running for at least 3 minutes and if the intake manifold air temperature goesabove 86 C (187 F), the Engine ECM will initiate a Level 2 Warning. With the Level 2Warning, the Engine ECM signals the engine to initiate a 3% derate. This derate will have a20% upper limit.


82 86 87 88 89 90 91 92

18%

15%

12%

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6%

3%

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Intake Manifold Temperature C

% D

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C11-C32 ENGINE INTAKE MANIFOLD TEMPERATURE DERATE

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21%

Level 1Warning Level 2 Warning / Derates

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Virtual Exhaust Temperature Derate

An engine derate can occur due to a estimated (virtual) high exhaust gas temperature. TheEngine ECM monitors the barometric pressure, the intake manifold temperature, and the enginespeed to estimate exhaust gas temperature. The following conditions are monitored todetermine if the engine derate should be enabled:

- high altitude- high ambient temperatures- high load and full accelerator pedal throttle- barometric pressure- intake manifold air temperature, and engine speed

The Engine ECM determines a maximum fuel delivery percentage to maintain safe maximumpower output under load. This calculation is new to the off-road Tier III engines and is used inplace of the previous altitude compensation derate strategy.

This event informs the mechanic that a derate has occurred because of operating conditions.Generally, this situation is normal and requires no service action.


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The Engine ECM will process all derate inputs in the highest derate priority selector. Themost critical derate condition input will be used to adjust fuel system delivery limiting enginepower to a safe level for the conditions in which the product is being operated, thereby preventelevated exhaust temperatures.

The virtual exhaust temperature derate will log a 194 event code. The derate will enable aLevel 1 Warning and eventually a Level 2 Warning. The level of the warning will depend onthe conditions that are sent to the Engine ECM.

The following conditions must be met in order to initiate a virtual exhaust temperature derate.

- No CID 168 01 FMI (low battery voltage to the Engine ECM) are active.- No active intake manifold air pressure sensor faults.- No active atmospheric pressure (barometric) sensor faults- No +5 V sensor voltage codes active.- The virtual exhaust temp derate must be the highest derate.- More fuel is being requested than the virtual exhaust temp derate will allow.

This derate is triggered by the information inferred by the Engine ECM, rather than anindividual sensor as with the previous single derate strategies. If you think this derate ispossibly being imposed incorrectly check for event codes on the high intake manifold airtemperature and correct those first. Also, make sure the aftercooler is unobstructed. Foradditional information about troubleshooting, refer to the troubleshooting manual for theparticular engine that is being serviced.


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The fuel pressure regulator (1) is located in the secondary fuel filter base (3). The fuel pressureregulator is used to maintain fuel pressure in the fuel gallery.

Also shown is the electric fuel priming pump (2) that is located on the primary fuel filter base (4).


1

2

3

4

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Engine Idle Management System (EIMS) sets the engine idle to maximize fuel efficiency.Also, this system uses new and improved software to benefit the customer with reduced soundlevels, reduced emissions, machine ability to set machine parameters to the working conditions,machine ability to set machine to working applications, and increased battery durability.

Work Mode - This mode allows the working idle to be programmed according to the customer'sapplications requirements. The work mode idle can be adjusted to a higher or lower rpmthrough Caterpillar Electronic Technician (ET). The engine idle range is between 650 rpm and1000 rpm. In order to go into the work mode, the percentage of fan bypass must be less than23%.

Warm up Mode - In a cold weather operation, the default engine rpm will be set to 1100 rpm inorder to generate additional engine heat, keeping the engine warmer. This mode monitors thecoolant temperature and intake manifold temperature. When the coolant temperature is below80 C (176 F) or the intake manifold temperature is below 15 (60 F) and the warm mode isenabled, the machine will time out for 10 minutes. After ten minutes, the coolant temperatureis below 70 C (158 F) and the machine has been in the warm up mode, the engine will be inwarm up mode. If the machine has not been in warm up mode but the intake manifoldtemperature is less than 5 C (41 F), the engine will go into the warm up mode.


ENGINE IDLE MANAGEMENT MODES

- Work Mode

- Warm Up Mode

- Hibernate Mode

- Low Voltage Mode

Also, the transmission speed selector must be in the NEUTRAL position, the parking brakeengaged, and the throttle position sensor output less than 5% for the engine to go to the warmup mode idle.

Hibernate Mode - This mode is initiated only when the transmission speed selector switch is inthe NEUTRAL position, the parking brake is engaged, the throttle position sensor output is lessthan 5%, the coolant temperature is above the EIMS default, the fan bypass is above 23%, andthe implement control levers are not activated. When these parameters are met along with a 10second period after the parking brake is engaged, the hibernate mode will lower the engine idleto 600 rpm. The engine will idle at 600 rpm until one of the above parameters are no longermet.

Low Voltage Mode - In this mode, the engine idle will ramp up to 1100 rpm when the batteryvoltage drops below 24.5 VDC and he engine has been running for 5 minutes. The low voltagemode feature is standard on all machines with EIMS with high current drain due to heavyelectrical loads from custom attachments. When the battery voltage is greater than 24.5 VDC,the engine idle will return to the current working low idle speed. The 24.5 battery voltage is adefault and can not be reconfigured in ET.


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POWER TRAIN

This illustration shows the major components in the power train.

Power from the engine flows to a 360 mm (14.5 inch) diameter torque converter. The torqueconverter output shaft is splined to the input shaft of the electronically controlled power shifttransmission.

The transmission output shaft is splined to the output transfer gear. The output transfer geartransmits power from the transmission to the front and rear drive shafts.

Power from the transmission output shaft flows through the front drive shaft and the parkingbrake to the front pinion, the bevel gear, the differential and the axles to the final drives.

Power from the transmission output shaft also flows through the rear universal joint group tothe rear pinion, the bevel gear, the differential and the axles to the final drives.

Power train movements and operations are controlled through the Power Train ECM.


ACERTEngine

Output TransferGear Case

FrontFinal Drive

RearFinal Drive

RearDrive Shaft

TorqueConverter

Transmission andModulating Valves

FrontDrive Shaft

ParkingBrake

Power TrainECM

Upshift, DownshiftDirection Switches

POWER TRAIN COMPONENTS

The Power Train Electronic Control Module (ECM) is the central component in thetransmission electronic control system. The ECM is located at the right rear of the cab. Therear panel must be removed for access to the ECM. The Power Train ECM will be locatedbehind the operators seat and have the connectors horizontal to each other.

The ECM makes decisions based on switch-type and sensor input signals and memoryinformation. Input signals to the ECM come from the operator's station, the machine, and thetransmission.

The operator's station input components consist of: the direction and shift switches, theneutralizer and neutralizer override switches, the park brake switch, the key start switch, andthe Auto/Manual select switch. Optional switch inputs are the ride control switch and thesecondary steer test switch.

The machine input components are: the engine speed sensor, the primary steering pressureswitch, the optional secondary steering pressure switch, and the Caterpillar Monitoring Systemmessage center module.

The transmission input components are the transmission oil temperature sensor, the torqueconverter output speed sensor, and the two transmission output speed sensors.

The ECM communicates with other electronic control modules, such as the CaterpillarMonitoring System, the Engine Electronic Control Module (ECM), and the ImplementElectronic Control Module (ECM) through the Cat Data Link. The Cat Data Link allows theTransmission ECM to receive and send information.

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The power train uses the A4M1 Electronic Control Module (ECM). To enable the ECM forpower train functions, contact (J1-27) is grounded and contact (J1-32) is grounded in order toenable the ECM.

The Power Train ECM responds to machine control decisions by sending a signal to theappropriate circuit which initiates an action. For example, the operator selects an upshift withthe shift lever. The Power Train ECM interprets the input signals from the shift lever, evaluatesthe current machine operating status, and energizes the appropriate modulating valve.

The Power Train ECM receives three different types of input signals:

1. Switch input: Provides the signal line to battery, to ground, or to open.

2. PWM input: Provides the signal line with a square wave of a specific frequency and avarying positive duty cycle.

3. Speed signal: Provides the signal line with either a repeating, fixed voltage level patternsignal or a sine wave of varying level and frequency.

The Power Train ECM has three types of output drivers:

1. ON/OFF driver: Provides the output device with a signal level of +Battery voltage(ON) or less than one Volt (OFF).

2. PWM solenoid driver: Provides the output device with a square wave of fixedfrequency and a varying positive duty cycle.

3. Controlled current output driver: The ECM will energize the solenoid with 1.25 ampsfor approximately one half second and then decrease the level to 0.8 amps for theduration of the on time. The initial higher amperage gives the actuator rapid responseand the decreased level is sufficient to hold the solenoid in the correct position. Anadded benefit is an increase in the life of the solenoid.

The Power Train ECM controls the transmission speed and directional clutches. The PowerTrain ECM interprets signals from the shift lever to signal the transmission to perform thefollowing options: Upshift, Downshift, Forward Neutral, and Reverse.

The Power Train ECM communicates through the CAT Data Link. The CAT Data Link allowshigh speed proprietary serial communications over a twisted pair of wires. The CAT Data Linkallows different systems on the machine to communicate with each other and also with servicetools such as Caterpillar Electronic Technician (ET).

The Power Train ECM has built-in diagnostic capabilities. As the Power Train ECM detectsfault conditions in the power train system, it logs the faults in memory and displays them onthe Caterpillar Monitoring System.


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Power Train Electrical System

This illustration shows the input components which provide power or signals to the PowerTrain ECM.

Power Train ECM Inputs:

Shift lever (Forward, Neutral, Reverse, and Gear): Combines control of the transmissionshifting to a single input device. The shift lever can be pushed forward, backward, or placed inthe middle position for machine direction. The lever is rotated in order to change the speeds ofthe transmission. This is the standard control for shifting that comes with the Hand MeteringUnit (HMU) steering.

Direction switch (Forward, Neutral, Reverse, Upshift, and Downshift): Combines controlof the transmission shifting with a single input device. The 3 position switch controls directionand the 2 thumb-switches controls upshift and downshift. This is the control for shifting thatcomes with the Command Control Steering (CCS).

Key start switch: Provides a signal to the Power Train ECM when the operator wants to startthe engine. The direction switch/shift lever must be in the NEUTRAL position before thePower Train ECM will permit engine starting.


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English 966h and 972h Whell Loaders (2)

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Transcript of English 966h and 972h Whell Loaders (2)