Systems Operation

Usage:

General Information

Component Locations

Component Locations
(1) Secondary fuel filter. (2) Rack Solenoid (BTM). (3) Electronic Control Module (ECM). (4) Fuel injection pump. (5) Timing Solenoid (BTM). (6) Fuel transfer pump. (7) Primary fuel filter. (8) Transducer Module. (9) Ratings Personality Module.

Cylinder And Valve Location

The Caterpillar 3406B (PEEC) Truck Engine is an inline 6 cylinder arrangement with a bore of 137 mm (5.4 in) and a stroke of 165 mm (6.5 in) giving a total displacement of 14.6 liter (893 cu in) displacement. The firing order is 1,5,3,6,2,4 and the direction of crankshaft rotation is counterclockwise, as viewed from the flywheel. The engine is turbocharged and air-to-air aftercooled with direct fuel injection.

The Programmable Electronic Engine Control (PEEC) system was designed to provide electronic governing, automatic air-fuel ratio control, torque rise shaping, injection timing control, and system diagnostics. Additional benefits such as Cruise Control, Vehicle Speed Limiting, Low And High Gears RPM Limiting (progressive shift engine speed control), PTO Governor, Idle Shutdown Timer and Data Link provide for additional engine economy, driver comfort, and serviceability.

A full range electronic governor controls the fuel injection pump output to maintain the engine rpm desired by the PEEC system.

Individual injection pumps, one for each cylinder, meter and pump fuel under high pressure to an injection nozzle for each cylinder. Electronic timing advance control provides the best fuel injection timing over the full range of engine speed.

Starting The Engine

The PEEC equipped engine may need to crank slightly longer than a mechanically governed engine, because some oil pressure is required for the electronic actuator to move the rack. The check engine light should be ON while the engine is cranking, but should GO OUT, within 10 seconds after the engine starts. At temperatures below 0°C (32°F), it may be necessary to spray starting fluid into the air cleaner inlet. If the engine fails to start in 30 seconds, release the starter switch. Allow the starter motor to cool for two minutes before using it again.

Cold Mode Operation

The PEEC system automatically idles the engine at 900 to 1000 rpm for the correct warm up time after a cold engine start [approximately less than 5°C (40°F)]. The PEEC system periodically checks the engine response and will reduce the idle speed down to the programmed low idle, when the engine is warm enough to drive the truck. The PEEC system considers the engine warm enough to drive when the engine response is acceptable, vehicle speed reaches 30 mph, or 15 minuets have expired. The time needed for the engine to reach the normal mode of operation is usually less than the time necessary for a walk-around-inspection of the vehicle.

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NOTICE

A truck equipped with a 3406B PEEC Engine should not be moved until it is out of the cold mode. If the engine is operated in the cold mode, rpm will be reduced to 1700 rpm and power will be noticeably reduced.

After Cold Mode is completed, the truck should be operated at low rpm and low power until normal operating temperature is reached. The engine will reach normal operating temperature faster when driven at low rpm and low power demand than when idled at no load. Typically the engine should be up to operating temperature by just driving through the yard toward the open road.

Shutoff Solenoid Override

A manual shutoff solenoid override lever is located on the side of the fuel pump. The engine can be shut off by rotating the manual shutoff lever in the counterclockwise (CCW) direction. Rotating the manual shutoff lever in the clockwise (CW) direction disables the shutoff solenoid.

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DO NOT operate the engine without the Rack Solenoid (BTM) in place and with the fuel shutoff solenoid disabled. Excessive engine speed may result.

Idle Shutdown Timer

The Idle Shutdown Timer is a feature of the electronic control system that can be selected by the customer. This feature, one of the customer specified parameters, may be programmed by the ECAP service tool. The Idle Shutdown Timer may be programmed from three to sixty minutes in one minute increments.

The Idle Shutdown Timer feature will shut down the engine after a time period specified by the customer. The following conditions must be met to enable the Idle Shutdown Timer:

1. Idle shutdown timer feature has been selected.

2. Parking brake must be set.

3. Engine must be at operating temperature.

4. Vehicle speed must be at "0" mph.

5. No engine load.

6. Parking brake switch installed.

Ninety seconds before the programmed idle time is reached, the diagnostic lamp will start to flash at a rapid rate. If the clutch pedal or service brake pedal indicate a position change during this final ninety (90) seconds, (diagnostic lamp flashing), the Idle Shutdown Timer will be disabled until the parking brake is again reset.

Customer Specified Parameters

The engine is capable of being programmed for several customer specified parameters. It allows the owner to select horsepower ratings within a "family" to more efficiently match the vehicle to the application. This "Engine Power Rating", combined with the other available customer specified parameters, are generally programmed so the vehicle will achieve optimum fuel efficiency and operator convenience. For a complete list of the customer specified parameters see the topic: Electronic Control Module (ECM), Personality Module, and Transducer Module. For a brief explanation of each of the customer specified parameters, see the Operation and Maintenance Manual.

Glossary Of PEEC Terms

Boost Pressure Sensor: This sensor measures inlet manifold air pressure and sends a signal to the ECM.
Brushless Torque Motor (BTM): Solenoid used to move fuel rack servo spool valve and timing advance spool valve.
Customer Specified Parameter: A Parameter that can be changed and whose value is set by the customer.
Data Link: An electrical connection for communication with other microprocessor based devices that are compatible with the proposed American Trucking Association and SAE Standard such as, trip recorders, electronic dashboards, and maintenance systems. The Data Link is also the communication medium used for programming and troubleshooting with Caterpillar service tools.
Digital Diagnostic Tool (DDT): A Caterpillar service tool used to program and for diagnosis of the 3406B PEEC system.
Electronic Control Analyzer and Programmer (ECAP): A Caterpillar service tool used to program and for diagnosis of a variety of electronic controls. An ECAP is needed for advanced diagnostic and programming functions not possible with a DDT.
Electronic Control Module (ECM): The microprocessor based ECM that provides power to the PEEC electronics, monitors PEEC inputs and acts as an governor to control engine rpm.
Engine Speed Sensor: A magnetic pickup that measures engine speed from the rotation of the fuel injection pump camshaft (slotted retainer). The electro-magnetic pickup requires an operating voltage.
Oil Pressure Sensor: This sensor measures engine oil pressure and sends a signal to the ECM.
Parameter: Any of a set of physical properties whose values determine the characteristics or behavior of the engine and/or vehicle in which the engine is installed.
Personality Module or Ratings Personality Module: This module is connected to the ECM and contains all the engine performance and emission calibrations for a specific rating family.
Programmable Electronic Engine Control (PEEC): The complete electronic system that monitors and controls engine operation under all conditions.
Pulse Width Modulation (PWM): A digital type of electronic signal corresponding to a measured variable. The length of the pulse (or signal) is controlled by the measured variable. This variable is quantified by the ratio of the percent of time "on" divided by the percent of time "off".
Rack Position Sensor: A linear position sensor which follows movement of the rack assembly and sends an electrical signal to the ECM.
Rack Solenoid (BTM): A rotary proportional solenoid (also called a BTM) used to move the fuel rack servo spool valve.
Throttle Position Sensor: An electronic sensor connected to the accelerator pedal and communicates pedal position to the ECM.
Timing Position Sensor: A linear position sensor which follows movement of the timing advance unit and sends an electrical signal to the ECM.
Timing Solenoid (BTM): A rotary proportional solenoid (also called a BTM) used to move the timing advance unit spool valve.
Total Tattletale: Total number of changes to all customer specified parameters.
Transducer: A device that converts a mechanical signal to an electrical signal.
Transducer Module: A sealed unit mounted below the rack actuator housing and contains the engine Oil Pressure Sensor, Boost Pressure Sensor and protective signal conditioning circuitry.
Vehicle Speed Buffer: A device used to wave shape and amplify the output of the Vehicle Speed Sensor.
Vehicle Speed Sensor: An electro-magnetic pickup that measures vehicle speed from the rotation of gear teeth in the drive train of the vehicle.

Electronic Control System Components

PEEC Engine Components
(1) Timing Solenoid (BTM). (2) Rack Solenoid (BTM). (3) Ratings Personality Module. (4) Electronic Control Module (ECM). (5) Transducer Module.

The Programmable Electronic Engine Control (PEEC) system is integrally designed into the engine fuel system to electronically control fuel delivery and injection timing.

Major components of the system are: Timing Solenoid (BTM) (1), Rack Solenoid (BTM) (2), Ratings Personality Module (3), ECM (4), Transducer Module (5), a Vehicle Speed Buffer and several sensors.

The PEEC system uses three types of components which are input, control and output.

An input component is one that sends an electrical signal to the main control module. The signal sent varies in either voltage or frequency in response to change in some specific system of the vehicle. The control module sees the input sensor signal as information about the condition, environment, or operation of the vehicle.

A control component is that component of the system that receives the input signals. Electronic circuits inside the control evaluate the signals and supply electrical energy to the output components of the system in response to predertermined combinations of input signal values.

An output component is one that is operated by a control module. It receives electrical energy from the control group and uses that energy to either:

* Do work (such as move the fuel rack or timing advance) and thereby take an active part in regulating or operating the vehicle.* Give information or warning (such as a light or an alarm will do) to the operator of the vehicle or other person.

These components provide the ability to electronically program the engine to improve performance, fuel economy and driveability of the vehicle while meeting gaseous and noise emission regulations.

Complete PEEC System Schematic

The Programmable Electronic Engine Control (PEEC) system is integrally designed into the engine fuel system to electronically control fuel delivery and injection timing.

Various sensors feed vehicular and engine data to the ECM. These sensors monitor boost pressure, engine oil pressure, engine speed, fuel rack position, timing advance position, throttle position, vehicle speed, on/off ignition, cruise control, clutch and brake operations. The ECM processes this data and sends electronic signals to the solenoids that move the fuel rack and timing advance to optimize the efficiency and performance of the engine.

The PEEC system also has the following built-in functions:

* cruise control* vehicle speed limiting* engine speed limiting* progressive shift control strategy* power take off governing* on board diagnostics

A Data Link provided by PEEC is used to communicate engine information to other systems on the vehicle (such as a trip recorder or electronic dashboard), and to communicate with Caterpillar service tools to calibrate, troubleshoot and program PEEC.

PEEC Control Flow Diagram

Data Link

The PEEC system includes a Data Link intended for communication with other microprocessor based devices that are compatible with SAE Recommended Practices J1708 & J1587. The Data Link can reduce duplication of truck sensors by allowing controls to share information.

The Data Link is used to communicate engine information to other electronic vehicle control systems and to interface with Caterpillar service tools [Electronic Control Analyzer and Programmer (ECAP) and Digital Diagnostic Tool (DDT)].

The engine/vehicle information that is monitored and available on the Data Link include the following:

* Boost Pressure* Customer Specified Parameters.* Engine Identification* Engine Speed* Oil Pressure* Rack Position* Status And Diagnostic Information* Throttle Position* Vehicle Speed

Either the Electronic Control Analyzer and Programmer (ECAP) or the Digital Diagnostic Tool (DDT), can be used to program the customer specified parameters.

One method of programming the customer specified parameters that are selected by a customer, the Electronic Control Analyzer and Programmer (ECAP), is used. The tool plugs into the Data Link Connector to communicate with the ECM. The (ECAP) can be also be used to display real time values of all information available on the Data Link for diagnosing engine problems.

Programming of the customer specified parameters can be password protected to prevent unauthorized tampering or changing of the customer selected values. With the proper customer passwords, changing of limits such as Low Gears #1 RPM Limit (LoGr #1), Vehicle Speed Limit (VSL), Low Cruise Control Set Limit (LCC), etc. is quickly and easily accomplished. Reprogramming the ECM to operate within a different engine horsepower family requires a different Personality Module and engine iron changes. A Caterpillar dealer should be consulted for details.

An alternative method of programming the customer specified parameters that are selected by the customer can be done with the Digital Diagnostic Tool (DDT). This tool also plugs into the Data Link Connector to communicate with the ECM. The DDT, however, does not accept alpha/numeric passwords (all "factory" passwords are alpha/numeric). Thus, the DDT cannot be used to program some engine parameters.

The DDT will read "active" or current diagnostic codes which are generated by the ECM. The ECAP will read current, as well as "logged" or intermittent diagnostic fault codes that the ECM generates. A partial list of the diagnostic fault codes is listed below.

System Diagnostic Codes

For a complete listing of the diagnostic fault codes and an explanation of each, see Troubleshooting 3406B (PEEC) Truck Engine Test Procedures, Form No. SENR3479.

Diagnostic Lamp

The "check engine" light, on the truck dashboard, can be used as a diagnostic lamp to communicate status or operation problems of the electronic control system.

The "check engine" light will be ON and blink every five seconds whenever a diagnostic fault is detected by the ECM. The light should also be ON and flashing Diagnostic Code 55 whenever the START switch is turned ON, but the engine is not running. This condition will test whether the light is operating correctly.

If the "check engine" light comes on and stays on after initial start-up the 3406B PEEC has detected a system fault. The "check engine" light or service tools can be used to identify the diagnostic code.

The dash mounted Cruise Control Switches are used to interrogate the ECM for system status. With the Cruise Control Switch OFF, move the SET/RESUME switch to the RESUME position. The "check engine" light will begin to flash to indicate a 2-digit fault code while the SET/RESUME switch is held in the RESUME position. The sequence of flashes represents the system diagnostic message. The first sequence of flashes adds up to the first digit of the fault code. After a two second pause, a second sequence of flashes will occur which represents the second digit of the fault code. Any additional fault codes will follow, after a pause, and will be displayed in the same manner.

The "check engine" light is also used to monitor the Idle Shutdown Timer. Ninety seconds before the programmed idle time is reached, the diagnostic lamp will start to flash at a rapid rate. If the clutch pedal or service brake pedal indicate a position change during this final ninety (90) seconds, (diagnostic lamp flashing), the Idle Shutdown Timer will be disabled until the parking brake is again reset.

Electronic Control Module (ECM) And Personality Module

Electronic Control Module And Personality Module
(1) Control Module Plug (P2). (2) Data Link Receptacle (J1). (3) Personality Module. (4) Fuel inlet (from transfer pump). (5) Fuel outlet (to fuel filter base). (6) ECM.

The 3406B PEEC Engine uses a microprocessor based Electronic Control Module (ECM) which is isolation mounted on the rear left side of the cylinder block. The ECM (6) is cooled by fuel as it circulates through a manifold between two circuit boards in the control module. The fuel enters the control module, from the fuel transfer pump, at fuel inlet (4), and exits the control module at fuel outlet (5).

All inputs and outputs to the control module are designed to tolerate short circuits to battery voltage or ground without damage to the control. Resistance to radio frequency and electro-magnetic interference are designed into the 3406B PEEC system. The system has passed tests for interference cause by police radars, two-way radios and switching noise commonly encountered in on-highway applications.

The ECM power supply provides electrical power to all engine mounted sensors and actuators. Reverse voltage polarity protection and resistance to vehicle power system voltage "swings" or "surges" (due to sudden alternator load, etc.) have been designed into the ECM. In addition to acting as a power supply, the ECM also monitors all sensor inputs and provides the correct outputs to ensure desired engine operation.

The ECM contains memory to store customer specified parameters and identify a selected factory engine rating. This memory also contains a personality module identification code to deter unauthorized tampering or switching of rating personality modules and other pertinent manufacturing information.

The wiring harness provides communication or signal paths to the various sensors (boost sensor, speed/timing sensor), the Data Link Connector, and the engine/vehicle connectors.

The Personality Module (3), is attached to the ECM, and provides the instructions necessary for the ECM to perform its function. The Personality Module contains all the engine performance and certification information such as, the timing, fuel air ratio and rated rack control maps for a particular ratings group that utilizes common engine components. Any engine rating from a number of available ratings in that group can be selected through the Data Link by using a Caterpillar service tool. For example: with the same Personality Module, an engine can be programmed for any one of 6 Ratings from 213 kW (285 hp) at 1600 rpm to 231 kW (310 hp) at 1900 rpm.

NOTE: The customer specified parameters include: Engine Power Rating, Vehicle Identification Number, PTO Vehicle Speed Limit (PTO VSL), PTO Engine RPM Limit (PTO RPM), Low Gears #1 RPM Limit (LoGr #1), Low Gears #2 RPM Limit (LoGr #2), Low Gears Turn Off Speeds (LoGr Off Limits), Engine RPM At Vehicle Speed Limit (Eng RPM At VSL), High Gears RPM Limit (HiGr RPM), Top Engine Limit (TEL), Vehicle Speed Limit (VSL), High Gear Turn On Speed (HiGr On), Low Cruise Control Set Limit (LCC), High Cruise Control Speed Set Limit (HCC), and Idle Shutdown Timer. The customer specified parameters may be secured by customer passwords. A 3406B (PEEC) ECM may have all parameters programmed or any combination of parameters programmed. For a brief explanation of each of the customer specified parameters, see the Operation and Maintenance Manual.

The ECM is programmed to run diagnostic tests on all inputs and outputs to partition a fault to a specific circuit (example, Throttle Position Sensor or the harness connecting it to the ECM). Once a fault is detected, it can be displayed (flashing coded display, representing a diagnostic fault code) on the dash mounted diagnostic lamp (see the topic, Diagnostic Lamp), or the diagnostic fault code can be read using a service tool (ECAP or DDT). A multimeter can be used to check or troubleshoot most problems. The ECM also will log or record most diagnostic codes generated during engine operation. These logged or intermittent codes can be read by the ECAP.

Idle Shutdown Timer

The Idle Shutdown Timer feature will shut down the engine after a time period specified by the customer. The following conditions must be met to enable the Idle Shutdown Timer:

1. Idle shutdown timer feature has been selected.

2. Parking brake must be set.

3. Engine must be at operating temperature.

4. Vehicle speed must be at "0" mph.

5. No engine load.

6. Parking brake switch installed.

Throttle Position Sensor

A cab mounted Throttle Position Sensor is used to eliminate the mechanical linkage between the engine and the operators' foot pedal. The Throttle Position Sensor is a rotary position sensor assembly which has 30° of active travel with and additional 5° of under travel and 10° over travel for linkage tolerance. It is environmentally protected for convenient mounting in the vehicle cab or on the engine side of the fire wall. The Throttle Position Sensor output is a constant frequency Pulse Width Modulated (PWM) signal rather than an analog voltage. The PWM signals overcomes the serious errors that can result from analog signals when pin to pin leakage or contamination occurs in the wiring harness and/or connectors.

The Throttle Position Sensor has been designed to comply with FMVSS124 for throttle return under environmental temperature extremes and with part of the throttle linkage missing. Two return springs for the Throttle Position Sensor are located behind the mounting disc. The engine returns to Low Idle if the PWM signal is invalid due to a broken or shorted wire.

Calibration of the Throttle Position Sensor must be done manually. Refer to the Testing And Adjusting Section of this service manual for the correct procedure to calibrate the Throttle Position Sensor.

Pedal-Mounted Throttle Sensor (If Equipped)

Pedal-Mounted Throttle Sensor

The Pedal-Mounted Throttle Sensor (if equipped) can be installed in place of the Throttle Position Sensor on earlier engines as long as the engine has the correct Personality Module.

The Pedal-Mounted Throttle Sensor is mounted on the back of the OEM-supplied pedal. Calibration of the Pedal-Mounted Throttle Sensor is done automatically by the ECM.

Vehicle Speed Buffer

A buffer circuit is used to amplify and wave shape the output of the magnetic Vehicle Speed Sensor. The Vehicle Speed Buffer is designed to operate with a magnetic speed pickup that detects vehicle speed from a chopper wheel located on the transmission output shaft. The Vehicle Speed Buffer prevents overloading of the magnetic pickup when multiple devices need to measure vehicle speed. The conditioned signal is transmitted to the ECM and other devices requiring vehicle speed. The buffer circuit should be located close to the magnetic speed pickup to minimize electrical noise interference.

The speedometer should receive its signal directly from the Vehicle Speed Buffer. Cruise control, gear parameters, PTO, Idle Shutdown Timer etc., may not function correctly if the speedometer is connected in some way other than the Vehicle Speed Buffer.

Transducer Module

Transducer Module
(1) Camshaft retainer (slotted). (2) Transducer Module. (3) Oil Pressure Sensor. (4) Boost Pressure Sensor.

The sealed Transducer Module is mounted below the rack actuator housing and contains an engine Oil Pressure Sensor, a Boost Pressure Sensor and protective signal conditioning circuitry. Engine oil pressure is supplied to the fuel rack servo and Oil Pressure Sensor by oil passages in the rack actuator center housing. A ceramic capacitive oil pressure transducer is used to limit engine speed if low oil pressure occurs. Boost pressure is routed to the Transducer Module. Wiring for the rack position and engine speed signals are passed through the Transducer Module to minimize external connections.

Fuel Rack Controls

Side View Of Rack Actuator And Fuel Injection Pump Group
(1) Shutoff solenoid. (2) Fuel rack servo. (3) Shutoff lever group. (4) Manual shutoff. Shutoff override shaft and lever assembly. (5) Clearance between cam retainer and sensor. (6) Camshaft retainer. (7) Spring. (8) Engine Speed Sensor. (9) Oil Pressure Sensor. (10) Boost Pressure Sensor. (11) Transducer Module.

Top View Of Rack Actuator
(2) Fuel rack servo. (12) Fuel rack. (13) Magnet. (14) Rack position sensor. (15) Nut. (16) Rack Solenoid (BTM).

Engine oil pressure is used to move the fuel rack. An electronically actuated Rack Solenoid (BTM) (16) controls a double acting hydraulic servo. The servo directs engine oil pressure to either side of a piston connected to fuel rack (12) which moves the piston and fuel rack as a unit.

Rack Solenoid (BTM) (16) is installed in the side of the rack actuator housing at the rear of the fuel injection pump and is controlled by the ECM. The lever of Rack Solenoid (BTM) (16) is engaged in a collar on the rack servo valve. Rack Solenoid (BTM) (16) is spring loaded toward the "Fuel Off" position and must receive a positive voltage to move in the "Fuel On" direction.

Rack position sensor (14) is located inside the rack actuator housing and is attached to fuel rack (12) by magnet (13). The Rack Position Sensor is a linear potentiometer used for accurate feedback information for the ECM.

In addition to the rack position data, the ECM receives data from four other sensors located in the rack actuator housing and Transducer Module. The Engine Speed Sensor (8) is triggered (signaled) by radial slots on the fuel injection pump camshaft retainer (6). The Transducer Module contains two sensors (9 and 10) monitoring oil pressure, and the boost pressure. The ECM will limit engine speed and power output of the engine if low oil pressure occurs. The control module adjusts the quantity of fuel or the timing of fuel delivered to the engine when a change in boost pressure is detected.

The ECM operates an energized to run shutoff solenoid (1). If Rack Solenoid (BTM) (16) is unable to move fuel rack (12) to the "Fuel Off" position, the shutoff solenoid (1) will apply an additional force on the fuel rack to move the rack to the "Fuel Off" position. A manually operated mechanical shutoff/solenoid override (4) is provided. The manual shutoff control shaft is spring loaded to a neutral position.

If the shutoff solenoid fails to energize, solenoid override (4) may be used to move the shutoff lever away from the servo valve (2). This will allow rack solenoid (16) to move the fuel rack even though the shutoff solenoid is not energized.

The manual shutoff (4) may be used to shut down the engine with the shutoff solenoid energized and power is maintained to the ECM. This method of shut down is used in some troubleshooting procedures.

The mechanical fuel ratio control, torque control group, and various adjustment screws have been eliminated. The ECM performs all of these functions. The control module adjusts engine power and torque rise to compensate for operating the engine at high altitudes or with plugged air cleaners, or to limit smoke.

The amount of fuel needed by the engine to maintain a desired rpm is determined by the ECM. With the engine running at a desired speed, the engine speed will decrease when an additional load is applied. The signal from Engine Speed Sensor (8) to the ECM changes. The control module receives this signal and other data, processes all the data, and sends a positive voltage to Rack Solenoid (BTM) (16). Rack Solenoid (BTM) (16) moves the valve in fuel rack servo (2) and fuel rack (12) moves in the "Fuel On" direction. The increase in fuel to the engine will increase engine speed. This action will continue until the engine is again running at the desired speed or until the rack position has increased up to a rack position limit.

With the engine running at a desired speed, the engine speed will increase when the load is decreased. The control module receives the changed signal from the Engine Speed Sensor (8). The ECM reduces the electrical signal to Rack Solenoid (BTM) (16). Rack Solenoid (BTM) (16) moves the valve in fuel rack servo (2), and fuel rack (12) moves in the "Fuel Off" direction. The decrease in fuel to the engine will decrease engine speed. This action will continue until the engine is again running at the desired speed.

With the PEEC system, when the engine is cranked to start there is no need to use the accelerator. The ECM will automatically provide the engine with the proper amount of fuel to start the engine. Since some oil pressure is required for the fuel rack servo to move the fuel rack, the 3406B PEEC engine may require a slightly longer cranking time to start.

A dash mounted "check engine" light should be on during cranking and should go out within 10 seconds after the engine starts running.

Governor Servo

Rack Movement Toward "Full Fuel"
(1) Piston. (2) Cylinder. (3) Sleeve. (4) Valve. (5) Fuel rack. (A) Oil inlet. (B) Oil outlet. (C) Oil passage. (D) Oil passage.

When the Rack Solenoid (BTM) is energized, it moves valve (4) to the left. The valve opens oil outlet (B) and closes oil passage (D). Pressure oil from oil inlet (A) pushes piston (1) and fuel rack (5) to the left. Oil behind the piston goes through oil passage (C), along valve (4) and out oil outlet (B).

No Rack Movement (Constant Engine Speed)
(1) Piston. (2) Cylinder. (3) Sleeve. (4) Valve. (5) Fuel Rack. (A) Oil inlet. (B) Oil outlet. (C) Oil passage. (D) Oil passage.

When the desired engine speed is reached, the Rack Solenoid (BTM) holds valve (4) in a fixed position. Piston (1) moves to the left until both oil outlet (B) and oil passage (D) are blocked by valve (4). Oil is trapped in the chamber behind piston (1) and creates a hydraulic lock which stops piston and fuel rack movement.

Rack Movement Toward "Fuel Off"
(1) Piston. (2) Cylinder. (3) Sleeve. (4) Valve. (5) Fuel rack. (A) Oil inlet. (B) Oil outlet. (C) Oil passage. (D) Oil passage.

When the Rack Solenoid (BTM) is de-energized, spring force in the solenoid moves valve (4) to the right. The valve closes oil outlet (B) and opens oil passage (D). Pressure oil from oil inlet (A) is now on both sides of piston (1). The area of the piston is greater on the left side than on the right side of the piston. The force of the oil is also greater on the left side of the piston and moves the piston and fuel rack (5) to the right.

Timing Advance Unit

Front View Of Timing Advance Unit
(1) Timing Solenoid (BTM). (2) Timing Position Sensor. (3) Bellcrank.

The timing advance unit connects the drive end of the fuel injection pump camshaft with the timing gears in the front of the engine. The unit uses engine oil pressure to change the fuel injection timing. An electronically actuated Timing Solenoid (BTM) controls a double acting hydraulic servo. The double acting hydraulic servo, directs engine oil under pressure to either side of the drive carrier to advance or retard timing. The total timing advance range is 25 crankshaft degrees.

With the PEEC system, timing is controlled as a function of engine rpm, load demand (rack position), boost pressure, engine acceleration and throttle position. A linear potentiometer (timing position sensor) is used for accurate feedback control of the timing advance through the ECM and the Timing Solenoid (BTM). Timing Position Sensor (2) is located on top of the timing advance actuator housing. Bellcrank (3) is used to transfer linear motion of the timing advance unit to the end of Timing Position Sensor (2). Bellcrank (3) is in contact with a thrust bearing which is fastened to and follows the movement of the timing advance body assembly (10).

Timing Solenoid (BTM) (1) is installed toward the inside of the engine into the timing advance actuator housing. The Timing Solenoid (BTM) is spring loaded toward the retarded position and must receive a positive voltage from the ECM to move the servo valve spool to change fuel injection timing. The lever of Timing Solenoid (BTM) (1) is connected to servo valve spool (5) through sleeve (4).

Timing Advance Unit (Before Timing Advance Begins)
(1) Timing Solenoid (BTM). (4) Sleeve. (5) Valve spool. (6) Ring. (7) Gear. (8) Carrier. (9) Fuel injection pump camshaft. (10) Body assembly. (11) Bolt. (12) Ring.

The timing advance unit is connected to fuel injection pump camshaft. Bolts (11) pull rings (6 and 12) together to hold gear (7). Carrier (8) has two helical splines. The outer splines are in contact with the helical splines of ring (6) and the inner splines are in contact with the helical splines on fuel injection pump camshaft (9). When the engine is started, gear (7) drives fuel injection pump camshaft (9) through ring (6) and carrier (8).

Advance Timing

Maximum Timing Advance
(1) Timing Solenoid (BTM). (4) Sleeve. (5) Valve spool. (6) Ring. (7) Gear. (8) Carrier. (9) Fuel injection pump camshaft. (10) Body assembly. (11) Bolt. (12) Ring.

As the engine is started and begins to run, the ECM sends current to the Timing Solenoid (BTM) which moves valve spool (4) to the left in the above illustration. At this point valve spool (4) is put in a position to close off the oil passage to drain in body assembly (10). Engine lubrication oil flows through the fuel injection pump housing and through a passage in fuel injection pump camshaft (9) into body assembly (10) and is stopped by valve spool (4). With oil flow stopped, oil pressure pushes body assembly (10) and carrier (8) to the left. As carrier (8) is forced to the left by oil pressure, it slides between the helical splines on ring (6) and the helical splines on fuel injection pump camshaft (9). The helical splines on the carrier and ring, cause the camshaft to turn in relation to gear (7). This outward motion of the body assembly (10) causes the fuel injection timing to be advanced.

Retard Timing

Retard Timing
(1) Timing Solenoid (BTM). (4) Sleeve. (5) Valve spool. (6) Ring. (7) Gear. (8) Carrier. (9) Fuel injection pump camshaft. (10) Body assembly. (11) Bolt. (12) Ring.

When the ECM senses a need for engine timing reduction, the voltage to the Timing Solenoid (BTM) is reduced. Spring pressure in the Timing Solenoid (BTM) moves valve spool (4) to the right in the above illustration. This blocks the engine lubrication oil from drain, on the outer end of body assembly (10). The oil flows from fuel injection pump camshaft (9), through body assembly (10), around valve spool (4) and builds up pressure to move body assembly (10) and carrier (8) to the right. This action causes fuel injection pump camshaft (9) to turn in relation to gear (7) and fuel injection timing is retarded.

Timing Fully Retarded
(1) Timing Solenoid (BTM). (4) Sleeve. (5) Valve spool. (6) Ring. (7) Gear. (8) Carrier. (9) Fuel injection pump camshaft. (10) Body assembly. (11) Bolt. (12) Ring.

Oil Flow For Fuel Injection Pump, Rack Actuator And Automatic Timing Advance

Fuel Injection Pump And Rack Actuator
(1) Fuel rack servo. (2) Fuel injection pump housing. (3) Rack actuator housing. (4) Passage (oil supply from cylinder block). (5) Passage (oil drain into cylinder block). (6) Transducer Module.

Lubrication oil under pressure is supplied to the fuel injection pump housing from the left side of the cylinder block through passage (4). At this point part of the oil flows into a main oil passage in fuel injection pump housing (2) to give lubrication for the three pump camshaft bearings. At the camshaft bearing next to the rack actuator housing oil flows between the bearing and camshaft to lubricate the thrust bearing for the camshaft retainer. At the camshaft bearing on the drive end of fuel injection pump housing (2), oil flows into drilled passages in the camshaft to give a supply of oil to operate the timing advance unit. Oil drains from the camshaft bearings into the fuel injection pump housing. A drain hole in the housing keeps the level of oil in the housing even with the center of the camshaft. Oil drains from the housing, through drain port (5), back to the engine block.

From passage (4) part of the oil is directed back to passages formed between fuel injection pump housing (2) and the rack actuator center housing. Oil flows through these passages to two different locations. Some of the oil flows through a passage between the rack actuator housing and fuel injection pump housing (2) to Transducer Module (6) which sends an electrical signal to the Electric Control Module (ECM) to monitor engine oil pressure.

The remainder of the oil flows through a different passage, back through the fuel injection pump housing. This passage is connected to fuel rack servo (1). The fuel rack servo moves the fuel rack through a double acting piston.

The internal parts of the rack actuator housing are lubricated by oil leakage from fuel rack servo (1) and the oil thrown off by rotation of the camshaft retainer. Oil drains back through an opening between the lower part of the rack actuator housing and the fuel injection pump housing. The fuel injection pump housing has an oil drain passage (5) that is connected to the engine block.

Fuel System

Fuel System Schematic
(1) Fuel priming pump. (2) Fuel injection pump housing. (3) Fuel injection line. (4) Check valve. (5) Fuel injection nozzle. (6) Secondary fuel filter. (7) Fuel return line. (8) Fuel transfer pump. (9) Primary fuel filter. (10) Fuel tank. (11) Electronic Control Module.

As the engine is cranked and started, fuel transfer pump (8) pulls fuel from fuel tank (10) through primary fuel filter (9).

NOTE: When the engine has reached its normal operating temperature, inlet fuel temperature to transfer pump must not exceed 65°C (149°F). Fuel temperatures above 65°C (149°F) reduce the life of the electronics in the ECM and the transfer pump check valves. High fuel temperatures also reduce engine power output. Make sure fuel heaters are turned OFF in warm weather operating conditions.

From fuel transfer pump (8) the fuel is pushed through ECM (11) to keep the electric circuits cool. The cooling plate for the control module is a one piece die cast aluminum housing. Manifolds on top and bottom of the control module route fuel from the transfer pump through the cooling plate.

The fuel exits the ECM and flows through secondary fuel filter (6) to the fuel manifold in fuel injection pump housing (2).

Fuel pressure in the fuel manifold is determined by the fuel transfer pump spring. A constant bleed orifice is in the fuel return line elbow at the injection pump housing. This orifice lets a continuous flow of fuel go through fuel return line (7) back to fuel tank (10). This helps keep the fuel cool and free of air. The individual fuel injection pumps get fuel from the fuel manifold and push fuel at a very high pressure through fuel lines (3) to fuel injection nozzles (5). Each fuel injection nozzle has very small holes in the tip that change the flow of fuel to a very fine spray that gives good fuel combustion in the cylinder.

Fuel Heaters

Fuel heaters prevent plugging of the fuel filters in cold weather due to "waxing". The PEEC system does not dissipate enough heat into the fuel to preclude the use of fuel heaters. Non-thermostatically controlled fuel heaters can heat the fuel in excess of 65°C. High fuel temperatures reduce engine performance, transfer pump check valve, and PEEC system reliability.

Fuel Heaters Without Thermostatic Controls Must Never Be Used With The PEEC System.

Only thermostatically controlled or self regulating fuel heaters can be used.

Fuel Transfer Pump

The fuel transfer pump is a piston pump that is moved by a cam (eccentric) on the camshaft for the fuel injection pump. the transfer pump is located on the bottom side of the fuel injection pump housing.

Fuel Transfer Pump (Start Of Down Stroke) (Arrows Indicate Fuel Flow Direction)
(1) Push rod. (2) Piston. (3) Outlet check valve. (4) Pumping check valve. (5) Pumping spring. (6) Pump inlet port. (7) Inlet check valve. (8) Pump outlet port.

When the fuel injection pump camshaft turns, the cam moves push rod (1) and piston (2) down. As the piston moves down, inlet check valve (7) and outlet check valve (3) close. Pumping check valve (4) opens and allows the fuel below the piston to move into the area above the piston. Pumping spring (5) is compressed as the piston is pushed down by push rod (1).

As the fuel injection pump camshaft continues to turn, the cam no longer puts force on push rod (1). Pumping spring (5) now moves piston (2) up. This causes pumping check valve (4) to close. Inlet check valve (7) and outlet check valve (3) will open. As the piston moves up, the fuel in the area above the piston is pushed through the outlet check valve (3) and out pump outlet port (8). Fuel also moves through pump inlet port (6) and inlet check valve (7) to fill the area below piston (2). The pump is now ready to start a new cycle.

Fuel Transfer Pump (Start Of Up Stroke) (Arrows Indicate Fuel Flow Direction)
(1) Push rod. (2) Piston. (3) Outlet check valve. (4) Pumping check valve. (5) Pumping spring. (6) Pump inlet port. (7) Inlet check valve. (8) Pump outlet port.

Fuel Injection Pump

The fuel injection pump increases the pressure of the fuel and sends an exact amount of fuel to the fuel injection nozzle. There is one fuel injection pump for each cylinder in the engine.

Fuel Injection Pump
(1) Spill port. (2) Check valve. (3) Pump barrel. (4) Bypass port. (5) Pump plunger. (6) Spring. (7) Fuel rack. (8) Gear. (9) Lifter. (10) Cam.

The fuel injection pump is moved by cam (10) of the fuel pump camshaft. When the camshaft turns, the cam raises lifter (9) and pump plunger (5). The pump plunger always makes a full stroke. As the camshaft turns farther, spring (6) returns the pump plunger and lifter to the bottom of the stroke.

Pump Barrel And Plunger Assembly
(1) Spill port. (2) Check valve. (3) Pump barrel. (4) Bypass port. (5) Pump plunger. (11) Orificed reverse flow check valve. (12) Spring. (13) Spring. (14) Scroll. (15) Slot.

When the pump plunger is at the bottom of the stroke, fuel at transfer pump pressure flows through spill port (1) and bypass port (4). Fuel fills pump barrel (3) in the area above pump plunger (5).

After pump plunger (5) begins the up stroke, fuel will be pushed out bypass port (4) until the top of the pump plunger closes the port. As the pump plunger travels farther up, the pressure of the fuel increases. At approximately 690 kPa (100 psi), check valve (2) opens and lets fuel flow into the fuel injection line to the fuel injection nozzle.

When the pump plunger travels farther up, scroll (14) uncovers spill port (1). The fuel above the pump plunger goes through slot (15), along the edge of scroll (14) and out spill port (1) back to the fuel manifold. This is the end of the injection stroke. The pump plunger can have more travel up, but no more fuel will be sent to the fuel injection nozzle.

When spill port (1) is opened by plunger (5) the fuel nozzle closes and spring (13) closes check valve (2) as the pressure above plunger (5) drops below 690 kPa (100 psi). At the same time orificed reverse flow check valve (11) opens.

Orificed reverse flow check valve (11) closes when the fuel pressure in the fuel injection lines is 6900 kPa (1000 psi). This keeps the fuel in the injection line and above the reverse flow check valve at 6900 kPa (1000 psi).

NOTE: Reverse flow check valve (11) prevents rough idle by stopping any secondary injection of fuel between injection strokes. This valve is only effective below 8250 kPa (1200 psi) and has no effect above that pressure. When the engine is shutdown, the pressure is gradually released through a small groove on the bottom face of reverse flow check valve (11).

When the pump plunger travels down and uncovers bypass port (4), fuel begins to fill the area above the pump plunger again, and the pump is ready to begin another stroke.

The amount of fuel the injection pump sends to the injection nozzle on each pump stroke can be changed by the rotation of the pump plunger. Gear (8) is attached to the pump plunger and is in mesh with fuel rack (7). The ECM through an actuator and servo, moves the fuel rack which turns the fuel pump plungers according to the fuel needs of the engine. When the fuel rack turns the pump plunger, scroll (14) on the plunger changes the distance between the top of pump plunger and the point where scroll (14) uncovers spill port (1). The longer the distance from the top of the pump plunger to the point where scroll (14) uncovers spill port (1), the more fuel will be injected.

To stop the engine, the pump plunger is rotated so that slot (15) on the pump plunger is in line with spill port (1). The fuel will now go out the spill port and not to the injection nozzle.

Fuel Injection Nozzle

The fuel injection nozzle goes through the cylinder head into the combustion chamber. The fuel injection pump sends fuel with high pressure to the fuel injection nozzle where the fuel is made into a fine spray for good combustion.

Fuel Injection Nozzle
(1) Carbon dam. (2) Seal. (3) Passage. (4) Filter screen. (5) Inlet passage. (6) Orifice. (7) Valve. (8) Diameter. (9) Spring.

Seal (2) goes against the nozzle adapter and prevents leakage of compression from the cylinder. Carbon dam (1) keeps carbon out of the bore in the nozzle adapter.

Fuel with high pressure from the fuel injection pump goes into inlet passage (5). Fuel then goes through filter screen (4) and into passage (3) to the area below diameter (8) of valve (7). When the pressure of the fuel that pushes against diameter (8) becomes greater than the force of spring (9), valve (7) lifts up. This occurs when the fuel pressure goes above the Valve Opening Pressure of the fuel injection nozzle. When valve (7) lifts, the tip of the valve comes off of the nozzle seat and the fuel will go through the six small orifices (6) into the combustion chamber.

The injection of fuel continues until the pressure of fuel against diameter (8) becomes less than the force of spring (9). With less pressure against diameter (8), spring (9) pushes valve (7) against the nozzle seat and stops the flow of fuel to the combustion chamber.

The fuel injection nozzle can not be disassembled and no adjustments can be made.

Air Inlet And Exhaust System

Air Inlet System
(1) Turbocharger. (2) Air line. (3) Exhaust elbow. (4) Aftercooler core.

The components of the air inlet and exhaust system control the quality and the amount of air available for combustion. These components are the air cleaner, turbocharger, aftercooler, cylinder head, valves and valve system components, piston and cylinder, and exhaust manifold.

Air Flow Schematic
(2) Air line. (4) Aftercooler core. (5) Inlet manifold. (6) Exhaust outlet from turbocharger. (7) Turbine side of turbocharger. (8) Compressor side of turbocharger.

Inlet air is pulled through the air cleaner, compressed and heated by the compressor wheel in compressor side of turbocharger (8) to about 150°C (300°F), then pushed through the air to air aftercooler core (4) and moved to the air inlet manifold at about 43°C (110°F). Cooling of the inlet air increases combustion efficiency, which helps to lower fuel consumption and increase horsepower output. Aftercooler core (4) is a separate cooler core installed in front of the standard engine radiator core of the truck. Ambient temperature air is moved across both cores by the engine fan and by the ram effect of the vehicles forward motion, this cools the turbocharged inlet air and the engine coolant.

From the aftercooler core the air is forced into the cylinder head to fill the inlet ports. Air flow from the inlet port into the cylinder is controlled by the intake valves.

Air Inlet And Exhaust System
(4) Aftercooler core. (6) Exhaust outlet. (7) Turbine side of turbocharger. (8) Compressor side of turbocharger. (9) Exhaust manifold. (10) Exhaust valve. (11) Intake valve. (12) Air inlet.

There are two intake and two exhaust valves for each cylinder. Intake valves open when the piston moves down on the inlet stroke. When the intake valves open, cooled compressed air from the inlet port is pulled into the cylinder. The intake valves close and the piston begins to move up on the compression stroke. The air in the cylinder is compressed. When the piston is near the top of the compression stroke, fuel is injected into the cylinder. The fuel mixes with the air and combustion starts. The force of combustion pushes the piston down on the power stroke. When the piston moves up again, it is on the exhaust stroke. The exhaust valves open, and the exhaust gases are pushed through the exhaust port into the exhaust manifold. After the piston makes the exhaust stroke, the exhaust valves close and the cycle (inlet, compression, power, exhaust) starts again.

Exhaust gases from exhaust manifold (9) enter turbine side of the turbocharger (7) and cause the turbine wheel to turn. The turbine wheel is connected to the shaft which drives the compressor wheel. Exhaust gases from the turbocharger pass through the exhaust outlet pipe, the muffler and the exhaust stack.

Turbocharger

Turbocharger
(1) Pipe. (2) Exhaust manifold. (3) Turbocharger.

The turbocharger (3) is installed on the center section of the exhaust manifold (2). All the exhaust gases from the engine go through the turbocharger. The compressor side of the turbocharger is connected to the aftercooler by pipe (1).

Turbocharger
(4) Air inlet. (5) Compressor housing. (6) Compressor wheel. (7) Bearing. (8) Oil Inlet port. (9) Bearing. (10) Turbine housing. (11) Turbine wheel. (12) Exhaust outlet. (13) Oil outlet port. (14) Exhaust inlet.

The exhaust gases go into turbine housing (10) through exhaust inlet (14) and push the blades of turbine wheel (11). The turbine wheel is connected by a shaft to compressor wheel (6).

Clean air from the air cleaners is pulled through the compressor housing air inlet (4) by the rotation of compressor wheel (6). The action of the compressor wheel blades causes a compression of the inlet air. This compression gives the engine more power because it makes it possible for the engine to burn more air and fuel during combustion.

When the load on the engine increases, more fuel is injected into the cylinders. This makes more exhaust gases, and will cause the turbine and compressor wheels of the turbocharger to turn faster. As the compressor wheel turns faster, more air is forced into the engine. The increased flow of air gives the engine more power because it makes it possible for the engine to burn the additional fuel with greater efficiency.

Maximum rpm of the turbocharger is controlled by the fuel setting, the high idle speed setting and the height above sea level at which the engine is operated. Programming of the fuel setting in the ratings Personality Module is done at the factory for a specific engine application.

Bearings (7 and 9) for the turbocharger use engine oil under pressure for lubrication. The oil comes in through the oil inlet port (8) and goes through passages in the center section for lubrication of the bearings. Oil from the turbocharger goes out through the oil outlet port (13) in the bottom of the center section and goes back to the engine lubrication system.

Valves And Valve System Components

The valves and valve system components control the flow of inlet air and exhaust gases into and out of the cylinder during engine operation.

Valve System Components
(1) Intake bridge. (2) Intake rocker arm. (3) Push rod. (4) Rotocoil. (5) Valve springs (inner and outer). (6) Valve guide. (7) Intake valves. (8) Lifter. (9) Camshaft.

Valve System Components
(1) Intake bridge. (2) Intake rocker arm. (7) Intake valves. (10) Exhaust rocker arm. (11) Exhaust bridge. (12) Exhaust valves.

The intake and exhaust valves are opened and closed by movement of these components: crankshaft, camshaft, lifters, push rods, rocker arms, bridges, and valve springs. Rotation of the crankshaft causes rotation of the camshaft. The camshaft gear is timed to, and driven by, a gear on the front of the crankshaft. As camshaft (9) turns, the cams of the camshaft also turn and cause lifters (8) to go up and down. This movement makes push rods (3) move rocker arms (2 and 10). Movement of the rocker arms will make intake and exhaust bridges (1 and 11) move up and down on dowels mounted in the cylinder head.

These bridges let one rocker arm open, or close, two valves (intake or exhaust) at the same time. There are two intake and two exhaust valves in each cylinder. Two valve springs (5) for each valve hold the valves in the closed position when the lifters move down.

Rotocoil assemblies (4) cause the valves to have rotation while the engine is running. This rotation of the valves keeps the deposit of carbon on the valves to a minimum and gives the valves longer service life.

Jake Brake

The Jake Brake permits the operator to control the speed of the vehicle on grades, curves, or anytime when speed reduction is necessary, but long applications of the service brakes are not desired. In downhill operation, or any slow down condition, the engine crankshaft is turned by the rear wheels (through the differential, driveshaft, transmission and clutch). To reduce the speed of the vehicle, an application of a braking force can be made to the pistons of the engine.

The Jake Brake, when activated, does this through the conversion of the engine from a source of power to an air compressor that absorbs (takes) power. This conversion is made possible by a master to slave piston arrangement, where movement of the rocker arm for the exhaust valves of one cylinder is transferred hydraulically to open the exhaust valves of another cylinder near the top of its normal compression stroke cycle. The compressed cylinder charge is now released into the exhaust manifold.

The release of the compressed air pressure to the atmosphere prevents the return of energy to the engine piston on the expansion (power) stroke. The result is an energy loss, since the work done by the compression of the cylinder charge is not returned by the expansion process. This energy loss is taken from the rear wheels, which provides the braking action for the vehicle.

Jake Brake Components

Jake Brake Installed (Typical Example)
(1) Rear Housing. (2) Front housing. (3) Stud. (4) Support bracket.

The Jake Brake consists of two different housings, one installed in each of the valve mechanism compartments above the rocker arms and rocker arm shaft. Each housing is positioned over three cylinders, and is mounted on two support brackets (4) and on two studs (3) at the end rocker shaft brackets. Special exhaust rocker arm adjusting screws and exhaust valve bridges are necessary. Later engines have only one support bracket (4) for each housing.

NOTE: Only the engine valves and valve mechanism for the exhaust side of the cylinders are used in the operation of the Jake Brake.

A spacer is used on top of the valve cover base to permit installation of the valve cover. The increase in height with the Jake Brake installed is less than 50.8 mm (2.00 in).

Both the front and rear Jake Brake housings consist of the parts that follow: three master pistons, three slave pistons, three control valves, and one solenoid valve.

Jake Brake Operation

Master-Slave Circuit Schematic
(1) Solenoid valve. (2) Spring. (3) Control Valve. (4) High pressure oil passage. (5) Slave piston adjustment screw. (6) Master piston. (7) Rocker arm shaft oil passage. (8) Engine oil pump. (9) Ball check valve. (10) Slave piston. (11) Rocker arm. (12) Spring. (13) Rocker arm adjustment screw. (14) Oil drain passage. (15) Low pressure oil passage. (16) Exhaust valve bridge. (17) Exhaust push rod. (18) Engine oil pan. (19) Exhaust valves.

The Jake Brake operates with engine oil which is supplied from the rocker arm shafts. Solenoid valve (1) controls the oil flow in the housing.

When the solenoid is activated, solenoid valve (1) moves down and closes oil drain passage (14) to oil pan (18). At the same time, it opens low pressure oil passage (15) to three control valves (3). As low pressure passage (15) is filled with engine oil, control valves (3) are pushed up in their chamber against force of spring (2). At this position, a groove in control valve (3) is in alignment with high pressure oil passage (4) that supplies slave piston (10) and master piston (6). Engine oil pressure will not lift ball check valve (9) and fill high pressure oil passage (4) and the chambers behind the slave and master pistons. This pressure moves the pistons down to a position where they will not make contact with the engine valve mechanism.

When the oil pressure is the same through all the oil passages, the small spring will force ball check valve (9) back against its seat. The system is now completely charged and ready for operation with engine valve mechanism. When the solenoid is activated, the Jake Brake is ready to operate in approximately 1/5 of a second.

When engine push rod (17) for the exhaust valves begins to move up on its normal exhaust cycle, rocker arm (11) and adjustment screw (13) move up to make contact with master piston (6). As master piston (6) begins to move up, the oil pressure increases in passage (4) because ball check valve (9) will not let the oil out. Since there is a constant increase in pressure with the rocker arm movement, slave piston (10) is forced down against exhaust valve bridge (16) (of a different cylinder) with enough force to open exhaust valves (19).

Oil Passage Schematic (Front Housing Shown)
(1) Solenoid valve. (3) Control valves. (4) High pressure oil passages. (6) Master pistons. (10) Slave pistons. (15) Low pressure oil passage.

This master-slave circuit is designed so that master piston (6) is only moved by an engine cylinder on the exhaust stroke, while slave piston (10) opens only the exhaust valves of an engine cylinder on the compression stroke (just before top center). The braking force is constant, and the sequence is the same as the firing order of the engine, as shown in the chart that follows:

When solenoid valve (1) is in the off position, the engine oil supply passage is closed, and oil drain passage (14) to the oil pan is opened. This lets oil drain from beneath control valve (3), and spring (2) pushes control valve (3) to the bottom of the chamber. This position lets oil from high pressure oil passage (4) drain into the chamber above the control piston (chamber vents to atmosphere outside of housing). Spring (12) now moves master piston (6) up to its neutral position, away from rocker arm adjustment screw (13). The time necessary for the system to stop operation is approximately 1/10 of a second. The Jake Brake will not be able to operate now until the solenoid is activated again.

Jake Brake Controls

Control Circuit Schematic
(1) Solenoid. (2) Throttle switch. (3) Clutch switch. (4) Control switch (on dash). (5) Fuse. (6) Battery. (7) Diode.

The Jake Brake is activated electrically with three different switches connected in series in the circuit. A manually operated control switch (4) is located on the dash of the vehicle. This is a three position switch that permits an operator a selection of 100%, 50%, or no retardation (braking force).

The next switch in series is clutch switch (3). Clutch switch (3) is set to permit brake operation only when the clutch is engaged. This prevents engine stall by the Jake Brake when the drive line is not engaged with the engine.

The third switch is throttle switch (2), and it permits Jake Brake operation only when the throttle is at idle position. Any application of more throttle (fuel increase) will stop current flow and the Jake Brake will not operate.

Clutch switch (3) and throttle switch (2) work automatically after the operator control switch (4) is manually positioned. This control circuit permits any one of the three switches to prevent operation of the brake, but requires all three of the switches to be closed before operation can begin.

A small diode (7) is connected between the load side of the switch terminal and ground to protect the switch contacts from arcing.

Cruise Control And Exhaust Brake Wiring Schematic

Lubrication System

Engine Without BrakeSaver

Lubrication System Components
(1) Oil supply line to turbocharger. (2) Oil return line from turbocharger. (3) Oil cooler. (4) Oil manifold in cylinder block. (5) Oil filter. (6) Oil pan.

The lubrication system has the following components: oil pan, oil pump, oil cooler, oil filter, oil lines to and from the turbocharger and oil passages in the cylinder block.

Oil Flow Through The Oil Filter And Oil Cooler

Flow Of Oil (Engine Warm)
(1) Oil manifold in cylinder block. (2) Oil supply line to turbocharger. (3) Oil return line from turbocharger. (4) Oil filter. (5) Bypass valve for the oil filter. (6) Oil pan. (7) Oil pump. (8) Bypass valve for the oil cooler. (9) Suction bell. (10) Oil cooler.

With the engine warm (normal operation), oil comes from oil pan (6) through suction bell (9) to oil pump (7). The oil pump sends warm oil to the oil cooler (10) and then to oil filter (4). From the oil filter, oil is sent to oil manifold (1) in the cylinder block and to oil supply line (2) for the turbocharger. Oil from the turbocharger goes back through oil return line (3) to the oil pan.

Flow Of Oil (Engine Cold)
(1) Oil manifold in cylinder block. (2) Oil supply line to turbocharger. (3) Oil return line from turbocharger. (4) Oil filter. (5) Bypass valve for the oil filter. (6) Oil pan. (7) Oil pump. (8) Bypass valve for the oil cooler. (9) Suction bell. (10) Oil cooler.

With the engine cold (starting conditions), oil comes from oil pan (6) through suction bell (9) to oil pump (7). When the oil is cold, an oil pressure difference in the bypass valve (installed in the oil filter housing) causes each valve to open. These bypass valves give immediate lubrication to all components when cold oil with high viscosity causes a restriction to the oil flow through the oil cooler (10) and oil filter (4). The oil pump then sends the cold oil through bypass valve (8) for the oil cooler and through bypass valve (5) for the oil filter to oil manifold (1) in the cylinder block and to supply line (2) for the turbocharger. Oil from the turbocharger goes back through oil return line (3) to the oil pan.

When the oil gets warm, the pressure difference in the bypass valves decreases and the bypass valves close. Now there is a normal oil flow through the oil cooler and oil filter.

The bypass valves will also open when there is a restriction in the oil cooler or oil filter. This action does not let an oil cooler or oil filter with a restriction prevent lubrication of the engine.

Engine With BrakeSaver

Lubrication System Components (Typical Illustration)
(1) Oil return line from turbocharger. (2) Oil supply line to turbocharger. (3) Oil manifold in cylinder block. (4) Oil cooler. (5) Oil filter. (6) oil pan.

The lubrication system has the following components: oil pan, two section oil pump, oil cooler, oil filter, oil lines to and from the turbocharger and oil passages in the cylinder block. The front section of the oil pump supplies oil for lubrication of the engine. The rear section of the oil pump supplies oil for operation of the BrakeSaver. The front section of the oil pump sends oil through the oil filter and the rear section of the oil pump sends oil through the oil cooler.

Oil Flow Through The Oil Filter

With the engine warm (normal operation), oil comes from oil pan (6) through suction bell (8) to the front section of the oil pump (7). The front section of the oil pump sends oil to oil filter (4). From the oil filter, oil is sent to oil manifold (1) in the cylinder block and to oil supply line (2) for the turbocharger. Oil from the turbocharger goes back through oil return line (3) to the oil pan.

With the engine cold (starting conditions), oil comes from oil pan (6) through suction bell (8) to the front section of oil pump (7). When the oil is cold, an oil pressure difference in the bypass valve (5) (installed in the oil filter housing) causes the valve to open. This bypass valve gives immediate lubrication to all components when cold oil with high viscosity causes a restriction to the oil flow through oil filter (4). The front section of the oil pump then sends the cold oil through bypass valve (5) for the oil filter to oil manifold (1) in the cylinder block and to supply line (2) for the turbocharger. Oil from the turbocharger goes back through oil return line (3) to the oil pan.

When the oil gets warm, the pressure difference in the bypass valve decreases and the bypass valve closes. Now there is a normal flow through the oil filter.

The bypass valve will also open when there is a restriction in the oil filter. This action does not let an oil filter with a restriction prevent lubrication of the engine.

Oil Flow Through The Oil Cooler

Flow Of Oil With BrakeSaver Off (Engine Warm)
(1) Oil cooler. (2) Bypass valve for the oil cooler. (3) BrakeSaver control valve. (4) BrakeSaver. (5) Oil pump (rear section). (6) Oil pan. (7) Suction bell.

With the engine warm (normal operation), oil comes from oil pan (6) through suction bell (7) to the rear section of oil pump (5). The rear section of the oil pump sends warm oil to the BrakeSaver control valve (3). If the BrakeSaver control valve is in the OFF position, it sends the warm oil to oil cooler (1) where it is made cool. From the oil cooler, the cool oil goes back through the BrakeSaver control valve to engine oil pan (6).

Flow Of Oil With BrakeSaver On (Engine Warm)
(1) Oil cooler. (2) Bypass valve for the oil cooler. (3) BrakeSaver control valve. (4) BrakeSaver. (5) Oil pump (rear section). (6) Oil pan. (7) Suction bell.

If BrakeSaver control valve (3) is in the ON position, the oil from the rear section of oil pump (5) that goes to the BrakeSaver control valve is now sent to BrakeSaver (4). After the oil goes through the BrakeSaver, it goes back to the BrakeSaver control valve. The control valve now sends the warm oil to oil cooler (1) where it is made cool. From the oil cooler, the cool oil goes back through the BrakeSaver control valve to engine oil pan (6).

Flow Of Oil With BrakeSaver Off (Engine Cold)
(1) Oil cooler. (2) Bypass valve for the oil cooler. (3) BrakeSaver control valve. (4) BrakeSaver. (5) Oil pump (rear section). (6) Oil pan. (7) Suction bell.

When the engine is cold (starting conditions), the oil has a high viscosity. This high viscosity causes a restriction to the oil flow through oil cooler (1). When there is a restriction in the oil cooler, an oil pressure difference in bypass valve (2) causes the valve to open. When the bypass valve is open, oil from the rear section of oil pump (5) can go through the valve and drain back into engine oil pan (6).

Oil Flow In The Engine

Engine Oil Flow Schematic
(1) Bracket for rocker arm shaft. (2) Rocker arm shaft. (3) Oil passage to lifters. (4) Valve lifter bore. (5) Oil supply rocker shaft bracket. (6) Rocker arm shaft. (7) Oil supply rocker shaft bracket. (8) Oil passage to accessory drive (air compressor). (9) Oil passage to rocker shaft bracket and accessory drive. (10) Oil passage to idler gear shaft. (11) Oil passage to rocker shaft bracket. (12) Oil passage to the fuel injection pump housing. (13) Camshaft bearing. (14) Oil jet tubes. (15) Main bearing. (16) Oil manifold. (17) Oil passage from the oil pump to the oil cooler and filter. (18) Oil passage from the oil cooler and filter.

From oil manifold (16), oil is sent through drilled passages in the cylinder block that connect main bearings (15) and camshaft bearings (13). Oil goes through drilled holes in the crankshaft to give lubrication to the connecting rod bearings. A small amount of oil is sent through oil jet tubes (14) to make the pistons cooler. Oil goes through grooves in the bores for the front and rear camshaft bearings and then into oil passages (3) that connects the valve fifter bores (4). These passages give oil under pressure for the lubrication of the valve lifters.

Oil is sent from lifter bores (4) through passage (11) to an oil passage in bracket (5) (next to cylinder No. 4) to supply pressure lubrication to rear rocker arm shaft (2). Oil is also sent from front main bearing bore through passage (9) to an oil passage in front bracket (7) for front rocker arm shaft (6). Holes in the rocker arm shafts lets the oil give lubrication to the valve system components in the cylinder head.

The air compressor gets oil from passage (8) in the cylinder block, through passages in the timing gear housing and the accessory drive gear.

The idler gear gets oil from passage (10) in the cylinder block through a passage in the idler gear shaft installed on the front of the cylinder block.

The fuel injection pump housing gets oil from passage (12) in the cylinder block. The automatic timing advance unit gets oil from the fuel injection pump through a passage in fuel injection pump camshaft.

There is a pressure control valve in the oil pump. This valve controls the pressure of the oil coming from the oil pump. The oil pump can put more oil into the system than is needed. When there is more oil than needed, the oil pressure goes up and the valve will open. This allows the oil that is not needed to go back to the inlet oil passage of the oil pump.

After the lubricating oil has done its work, it goes back to the engine oil pan.

BrakeSaver

The BrakeSaver permits the operator to control the speed reduction of the vehicle on grades, curves, or at any time when speed reduction is necessary but long applications of the service brakes are not desired.

During downhill operation, the crankshaft is turned by the rear wheels (through the differential, driveshaft, transmission, and clutch). To reduce the speed of the vehicle, an application of a braking force can be made to the crankshaft. The BrakeSaver does this through the conversion of the energy of rotation into heat which is removed by the engine cooling system.

BrakeSaver Components

BrakeSaver Components
(1) Flywheel housing. (2) Rotor. (3) BrakeSaver housing. (4) Flywheel. (5) Crankshaft flange. (6) Ring gear plate. (7) Stator.

The BrakeSaver housing (3) is fastened directly to the rear face of flywheel housing (1). The BrakeSaver adds approximately four inches to the length of the engine drive train. A rotor (2) and a ring gear plate (6) are installed between the rear flange of crankshaft (5) and flywheel (4). The ring gear plate (6) permits the use of the standard engine starter motor. The rotor turns in a space between stator (7) and BrakeSaver housing (3).

BrakeSaver Components
(8) Oil pump (rear section). (9) BrakeSaver. (10) Tube. (11) Hole. (12) Bypass valve. (13) Baffle. (14) Oil pump (front section). (15) Engine oil pan. (16) BrakeSaver control valve. (17) Line. (18) Line.

The engine oil pump has two sections. The front section (14) of the oil pump gives oil to the engine for lubrication. Rear section (8) of the oil pump sends engine oil through BrakeSaver control valve (16) to BrakeSaver (9). The rear section of the oil pump also sends oil through line (17) to the engine oil cooler (not shown). From the oil cooler, the cool oil goes through line (18), through baffle (13) and back into engine oil pan (15).

When the BrakeSaver is turned off, tube (10) lets the oil in the BrakeSaver rapidly go out of the BrakeSaver and back into the engine oil pan.

When the engine is cold (starting conditions), the oil has a high viscosity. This high viscosity causes a restriction to the oil flow through the oil cooler. When there is a restriction in the oil cooler, an oil pressure difference in the bypass valve (12) causes the valve to open. When the bypass valve is open, oil from the rear section of the oil pump can go through hole (11) in bypass valve (12) to drain back into engine oil pan (15).

BrakeSaver Lubrication

BrakeSaver Lubrication
(1) Oil line. (2) Orifice. (3) Piston-type ring seal. (4) Orifice. (5) Chamber. (6) Piston-type ring seal. (7) Lip-type seal. (8) Lip-type seal. (9) Oil line.

Piston ring seals (3 and 6) keep pressure oil in chamber (5) around the rotor during operation. Lip-type seals (7 and 8) prevent oil leakage from the BrakeSaver. An outside oil line (1) from the engine lubrication system sends engine oil to the BrakeSaver housing. Orifices (2 and 4) in the BrakeSaver send oil to a space between the lip seals and the piston-type ring seals at a rate of 1.24 liter/min (.33 U.S. gpm). This oil gives lubrication to the seals under all conditions of operation.

The spaces between the lip-type seals and the piston-type seals are connected to an outside drain line (9) that lets the oil go back to the engine oil pan.

BrakeSaver Operation

In downhill operation, the crankshaft is turned by the rear wheels (through the differential, driveshaft, transmission, and clutch). To reduce the speed of the vehicle, an application of a braking force can be made to the crankshaft. The BrakeSaver does this through the conversion of the energy of rotation into heat which is removed by the engine cooling system.

BrakeSaver Housing And Rotor
(1) BrakeSaver housing. (2) Pockets. (3) Hole. (4) Pocket. (5) Rotor.

The rotor (5) is fastened to and turns with the engine crankshaft. The rotor has pockets (4) on the outer circumference of both sides and four holes (3) to permit equal oil flow to both sides of the rotor.

The BrakeSaver housing (1) and the stator are fastened to the flywheel housing and can not turn. Both the BrakeSaver housing and the stator have pockets (2) on their inside surfaces in alignment with the pockets (4) in the rotor.

Oil Flow Through BrakeSaver
(1) BrakeSaver housing. (2) Pocket. (4) Pocket. (5) Rotor. (6) Stator.

The rotor (5) turns in the compartment made by stator (6) and BrakeSaver housing (1). When the BrakeSaver housing is in operation, engine oil comes into this compartment near the center through a passage from the bottom of the BrakeSaver housing. The rotor, turning with the crankshaft, throws this oil outward. As the oil flows outward, the shape of rotor pockets (4) send the oil into pockets (2) of the stator and BrakeSaver housing. As the rotor turns and the oil flows around the BrakeSaver compartment, it takes the shape of a spiral.

As the oil flows around the BrakeSaver compartment, it is constantly cut by the vanes (the material between the pockets) of the rotor. This cutting action gives resistance to the rotor and changes the energy of the rotor into heat in the oil. The heat is removed by the oil cooler and goes into the engine cooling system.

Oil Flow In BrakeSaver
(1) BrakeSaver housing. (5) Rotor. (6) Stator. (7) Spiral flow. (8) Air pocket.

As the BrakeSaver inlet passage opens, more oil starts to flow in a spiral shape between the rotor and the stator. Inside this spiral flow (7) of oil is an air pocket (8). As the pressure in the rotor compartment increases, the amount of oil in the spiral flow increases in thickness and the air pocket has compression. As this air pocket has compression, the amount of oil being cut by the rotor vanes has an increase.

When the BrakeSaver is in operation, the level of braking can be controlled by the inlet oil pressure, since the braking force available is in direct relation to the amount of oil that is cut by the rotor vanes. When the BrakeSaver is not in operation, the inlet passage to the rotor compartment is closed by the control valve, and there is no oil in the BrakeSaver compartment.

BrakeSaver Control

BrakeSaver Oil Flow (Off)
(1) BrakeSaver control lever. (2) Oil cooler. (3) Valve spool. (4) BrakeSaver control valve. (5) Oil pump. (6) BrakeSaver. (7) Line. (8) Oil pan.

When the BrakeSaver control lever (1) is in the OFF position, spring force holds valve spool (3) against the cover at the air inlet end of control valve (4). With valve spool (3) in this position, oil pump (5) sends engine oil from oil pan (8) through control valve (4) to oil cooler (2). From the oil cooler, the oil goes through the control valve, through line (7) and back to engine oil pan (8). With the BrakeSaver control valve in this position, no oil is sent to BrakeSaver (6).

BrakeSaver Oil Flow (Fill)
(1) BrakeSaver control lever. (2) Oil cooler. (3) Valve spool. (4) BrakeSaver control valve. (5) Oil pump. (6) BrakeSaver. (7) Line. (8) Oil pan.

When BrakeSaver control lever (1) is moved to the ON position, pressure air moves valve spool (3) to the right against the spring force. With the valve spool in this position, engine oil from oil pump (5) is sent through control valve (4) to the rotor compartment of BrakeSaver (6). From the BrakeSaver, the oil goes through the control valve, through oil cooler (2), back through the control valve, and back into the BrakeSaver.

The oil cannot go back to engine oil pan (8) because the passage through the control valve to line (7) is closed by the valve spool.

The time required to fill the BrakeSaver with pressure oil to the point of maximum braking in the BrakeSaver is approximately 1.8 seconds.

BrakeSaver Oil Flow (Operate)
(1) BrakeSaver control lever. (2) Oil cooler. (3) Valve spool. (6) BrakeSaver. (8) Oil pan.

As BrakeSaver (6) fills, the turning rotor causes an increase in the oil pressure in the BrakeSaver. Inlet oil to the BrakeSaver and outlet oil from the BrakeSaver both go into the spring bore in valve spool (3). The average of the inlet oil pressure and the outlet oil pressure in the spring bore plus the force of the spring work against the pressure air on the left end of the valve spool. When the force of the pressure oil plus the spring force become larger than the force of the pressure air, the valve spool moves to the left. This movement causes a restriction in the passage for the inlet oil and an oil pressure decrease in the BrakeSaver.

A decrease in rotor speed (normally with a decrease in vehicle speed) causes a decrease in the oil pressure in the BrakeSaver. This causes a decrease in oil pressure in the spring bore of the valve spool which lets the pressure air on the left end of the spool move the spool to the right. This movement opens the passage for the inlet oil and the oil pressure in the BrakeSaver has an increase.

An increase in rotor speed will cause an increase in the oil pressure in the BrakeSaver. This increase in oil pressure will cause the valve spool to move to the left to give a restriction to the inlet oil to the BrakeSaver.

The valve spool is constantly moving to make adjustments to the BrakeSaver inlet pressure for compensation of the changing rotor speeds caused by normal operation of the vehicle. This constant movement of the valve spool is necessary to keep the amount of braking force in the BrakeSaver at the level set by control lever (1).

During normal operation, the outlet oil from the BrakeSaver goes to oil cooler (2). From the oil cooler, some of the oil (approximately 60%) goes back to the BrakeSaver inlet and the remainder of the oil from the oil cooler goes to engine oil pan (8).

BrakeSaver Oil Flow (Drain)
(1) BrakeSaver control lever. (2) Oil cooler. (3) Valve Spool. (4) BrakeSaver control valve. (5) Oil pump. (6) BrakeSaver. (7) Line. (8) Oil pan. (9) Line.

When BrakeSaver control lever (1) is moved to the OFF position, the pressure air on the left end of valve spool (3) goes out of control valve (4). With no pressure air in the valve, the pressure oil in the spring bore plus the spring force move the valve spool against the cover at the air inlet end of the control valve. This movement closes the BrakeSaver inlet passage. The rotor in BrakeSaver (6) now pushes the oil out of the BrakeSaver, through the control valve, through line (9), and back to oil pan (8).

The time required to remove the oil from the BrakeSaver is approximately 1.5 seconds.

With the control valve in this position, oil pump (5) sends oil through oil cooler (2) and through line (7) back to the oil pan.

Operator Controls

Two types of controls are available for the BrakeSaver: a manual control and an automatic control.

Manual Control Diagram
(1) Pressure reducing valve. (2) Manual control valve. (3) BrakeSaver control lever. (4) Air pressure gauge. (5) Oil temperature gauge. (6) BrakeSaver control valve.

Manual Control

Pressure air from the truck air system is sent to pressure reducing valve (1) where the air pressure is controlled to 345 kPa (50 psi). This controlled pressure air goes to manual control valve (2).

When the operator moves BrakeSaver control lever (3) toward the ON position, pressure air is sent to BrakeSaver control valve (6). The farther lever (3) is moved toward the ON position, the higher the pressure of the air sent to the BrakeSaver control valve. An increase in air pressure in the BrakeSaver control valve causes an increase in the oil pressure in the BrakeSaver. An increase in the oil pressure in the BrakeSaver causes an increase in the braking force in the BrakeSaver. The operator can give modulation to the braking force in the BrakeSaver through the movement of BrakeSaver control lever (3).

When the BrakeSaver is turned off, the pressure air goes out of the system through a passage in manual control valve (2). This lets the pressure air out of BrakeSaver control valve (6) and removes the braking force from the BrakeSaver.

An air pressure passage gauge (4) gives the operator a relative indication of the air pressure being sent to the BrakeSaver control valve. Through the use of the indication on the air pressure gauge in relation to engine rpm, the operator can get approximately the same braking effect from the BrakeSaver time after time. This lets the operator more easily control the desired wheel speed of the vehicle.

An oil temperature gauge (5) gives the operator an indication of the ability of the engine cooling system to control the heat in the BrakeSaver during its operation. If the gauge reads too HOT, move BrakeSaver control lever (3) to the OFF position and use the service brakes to control the wheel speed of the vehicle. With the BrakeSaver off, the oil temperature will rapidly become normal again and the BrakeSaver can be used.

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NOTICE

Do not manually engage the BrakeSaver and control the wheel speed with the accelerator. The design of the cooling system is for the control of the temperature of the oil at full engine power or full BrakeSaver capacity, but not both at the same time.

Automatic Control Diagram
(1) Manual control valve. (2) Pressure reducing valve. (3) Electronic Control Module (ECM). (4) Cruise control switch. (5) Clutch switch. (6) Air pressure gauge. (7) Double check valve. (8) BrakeSaver switch. (9) Service brake switch. (10) Throttle limit switch. (11) Oil temperature gauge. (12) BrakeSaver control valve. (13) Flyback diode. (14) Relay. (15) BrakeSaver solenoid valve. (16) Mode selector switch. (17) Battery.

Automatic Control

All the components of the manual control are in the automatic control and their functions are the same. In the automatic control, there is also a solenoid valve (15), a double check valve (7), and several switches. BrakeSaver solenoid valve (15) (when activated) sends pressure air from the pressure reducing valve (2) to the BrakeSaver control valve (12).

Solenoid valve (15) is connected to four switches: mode selector valve (16), throttle limit switch (10), cruise control switch (4), and clutch switch (5). The switches are connected to each other in series. When cruise control switch (4) is in the "OFF" position and switches (5), (10) and (16) are closed, relay (14) is activated and directs electric current from the battery to solenoid valve (15).

NOTE: Mode selector switch (16) can be used to de-energize solenoid valve (15) if relay (14) becomes stuck in the closed position.

The mode selector switch (16) has two positions: MANUAL and AUTOMATIC. For automatic operation of the BrakeSaver, the mode selector switch must be in the AUTOMATIC position.

NOTE: The BrakeSaver system is wired so the BrakeSaver automatic control cannot be activated while the PEEC system Cruise control switch is in the "ON" position. When the BrakeSaver is activated by manual control, the PEEC system Cruise Control Mode is deactivated.

Clutch switch (5) is connected to the clutch linkage. When the clutch is engaged (clutch pedal up), the switch is closed. For automatic operation of the BrakeSaver, the clutch switch must be CLOSED (pedal up).

NOTE: In vehicles with no clutch pedal, the clutch switch is removed from the circuit.

A throttle limit switch (10) is installed in the linkage for the throttle position sensor. When the accelerator is released (accelerator pedal up), the linkage returns to the low idle position and the switch is closed. For automatic operation of the BrakeSaver, the throttle limit switch must be closed (accelerator pedal up).

When the electric current opens solenoid valve (15), full air pressure [345 kPa (50 psi)] is sent through the double check valve (7) to BrakeSaver control valve (12). The double check valve keeps the pressure air from going out of the system through the manual control valve (1) when the control lever of manual control valve (1) is not in use. It also keeps the pressure air from going out of the system through solenoid valve (15) when the manual control is in use.

Because the solenoid valve sends full air pressure to the BrakeSaver control valve, there is no modulation in the AUTOMATIC position.

When the mode selector switch (16) is in the AUTOMATIC position and the accelerator pedal is released (pedal up), the BrakeSaver is operating at its maximum capacity. When the clutch is released (pedal down) the BrakeSaver goes off. When the clutch is engaged again (pedal up), the BrakeSaver comes back on. A light pressure on the accelerator pedal turns the BrakeSaver off and lets the vehicle run freely. More pressure on the accelerator pedal sends fuel to the engine.

When the BrakeSaver is turned off, the pressure air goes out of the system through a passage in manual control valve (1) or in solenoid valve (15). This lets the pressure air out of BrakeSaver control valve (12) and removes the braking force from the BrakeSaver.

Manual control valve (1) can be operated with mode selector switch (16) in the AUTOMATIC position. During normal operation, the solenoid valve will send full air pressure to the BrakeSaver control valve and remove the effect of the manual control valve. If there is a failure in the electrical system when the mode selector switch is in the AUTOMATIC position, the manual control valve will have an effect.

Manual control valve (1) can also be operated with the PEEC system in the Cruise Control Mode. Under this condition, Cruise control switch (4) is in the "ON" position as shown. During operation, air pressure is directed to BrakeSaver control valve (12) and is also directed to BrakeSaver switch (8). When BrakeSaver switch (8) opens, the cruise control circuit is disabled.

Cooling System

This engine has a pressure type cooling system equipped with a shunt line.

A pressure type cooling system gives two advantages. The first advantage is that the cooling system can have safe operation at a temperature that is higher than the normal boiling (steam) point of water. The second advantage is that this type system prevents cavitation (the sudden making of low pressure bubbles in liquids by mechanical forces) in the water pump. With this type system, it is more difficult for an air or steam pocket to be made in the cooling system.

NOTE: In air to air aftercooled systems, a coolant mixture with a minimum of 30% ethylene glycol base antifreeze must be used for efficient water pump performance. This mixture keeps the cavitation temperature range of the coolant, high enough for efficient performance. Dowtherm 209 Antifreeze can not be used because it does not raise the water pump cavitation temperature of the coolant high enough.

Cooling System (Engine Warm)
(1) Cylinder head. (2) Water temperature regulator. (3) Outlet hose. (4) Vent tube. (5) Shunt line. (6) Water elbow. (7) Water pump. (8) Cylinder block. (9) Oil cooler. (10) Inlet hose. (11) Radiator.

In operation water pump (7) sends most of the coolant from radiator (11) to oil cooler (9).

The coolant from oil cooler (9) goes through a bonnet and elbow into cylinder block (8). Inside the cylinder block, the coolant goes around the cylinder liners and up through the water directors into the cylinder head. The water directors send the flow of coolant around the valves and the passages for exhaust gases in the cylinder head. The coolant then goes to the front of the cylinder head. At this point, water temperature regulator (2) controls the direction of coolant flow.

If the coolant temperature is less than normal for engine operation, water temperature regulator (2) is closed. The coolant flows through the regulator housing and elbow (6) back to water pump (7).

If the coolant is at normal operating temperature (engine warm) water temperature regulator (2) is open and the coolant flows to radiator (11) through outlet hose (3). The coolant is made cooler as it moves through the radiator. When the coolant gets to the bottom of the radiator, it goes through inlet hose (10) and into the water pump.

NOTE: Water temperature regulator (2) is an important part of the cooling system. It divides coolant flow between radiator (11) and bypass [water elbow (6)] as necessary to maintain the correct temperature. If the water temperature regulator is not installed in the system, there is no mechanical control, and most of the coolant will take the path of least resistance through the bypass. This will cause the engine to overheat in hot weather. In cold weather, even the small amount of coolant that goes through the radiator is too much, and the engine will not get to normal operating temperatures.

Shunt line (5) gives several advantages to the cooling system.

1. The shunt line gives a positive coolant pressure at the water pump inlet to prevent pump cavitation.

2. A small flow of coolant constantly goes through shunt line (5) to the inlet of water pump (7). This causes a small amount of coolant to move constantly through vent tube (4) between the lower and upper compartment in the radiator top tank. Since the flow through the vent tube is small and the volume of the upper compartment is large, air in the coolant comes out of the coolant as it goes into the upper compartment.

3. The shunt line is a fill line when the cooling system is first filled with coolant. This lets the cooling system fill from the bottom to push any air in the system out the top.

Engines Equipped With A BrakeSaver

The cooling system for an engine with a BrakeSaver is the same as the cooling system for an engine with no BrakeSaver. The oil cooler on an engine with a BrakeSaver is larger but it is still found in the same location on the engine. It has the same water flow through it as the oil cooler on an engine with no BrakeSaver.

Coolant For Air Compressor

Coolant Flow In Air Compressor
(1) Outlet hose. (2) Air compressor. (3) Inlet hose.

The coolant for the air compressor (2) comes from the cylinder block through inlet hose (3) and into the air compressor. The coolant goes from the air compressor through outlet hose (1) back into the front of the cylinder head.

Coolant Conditioner (An Attachment)

Schematic Of Cooling System With Coolant Conditioner
(1) Coolant conditioner element. (2) Air compressor. (3) Shunt line. (4) Coolant outlet (to radiator). (5) Temperature regulator housing. (6) Coolant bypass (internal). (7) Cylinder liner. (8) Water pump. (9) Radiator. (10) Engine oil cooler. (11) Coolant inlet (from radiator).

Some conditions of operation have been found to cause pitting (small holes in the metal surface) from corrosion or cavitation erosion (wear caused by air bubbles in the coolant) on the outer surface of the cylinders liners and the inner surface of the cylinder block next to the liners. The addition of a corrosion inhibitor (a chemical that gives a reduction of pitting) can keep this type of damage to a minimum.

The "spin-on" coolant conditioner elements, similar to the fuel filter and oil filter elements, fasten to a base that is mounted on the engine or is remote mounted. Coolant flows through lines from the water pump to the base and back to the air compressor. There is a constant flow of coolant through the element.

The element has a specific amount of inhibitor for acceptable cooling system protection. As coolant flows through the element, the corrosion inhibitor, which is a dry material, dissolves (goes into solution) and mixes to the correct concentration. Two basic types of elements are used for the cooling system, and they are called the "PRECHARGE" and the "MAINTENANCE" elements. Each type of element has a specific use and must be used correctly to get the necessary concentration for cooling system protection. The elements also contain a filter and should be left in the system so coolant flows through it after the conditioner material is dissolved.

The "PRECHARGE" element has more than the normal amount of inhibitor, and is used when a system is first filled with new coolant (unless Dowtherm 209 Antifreeze is used). This element has to add enough inhibitor to bring the complete cooling system up to the correct concentration.

The "MAINTENANCE" elements have a normal amount of inhibitor and are installed at the first change interval and provide enough inhibitor to keep the corrosion protection at an acceptable level. After the first change period, only "MAINTENANCE" elements are installed at specified intervals to give protection to the cooling system.

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NOTICE

Do not use Dowtherm 209 Full-Fill in a cooling system that has a coolant conditioner. These two systems are not compatible (corrosion inhibitor is reduced) when used together.

Electrical System

Complete PEEC System Schematic

One thing different about the Programmable Electronic Engine Control (PEEC) from past Caterpillar electronic control systems is that several of the input components are electronic. These components require an operating voltage, and often times a reference voltage as well.

Unlike many electronic systems of the past, PEEC is not sensitive to the common external sources of noise, but electro-mechanical buzzers can cause disruptions in the power supply. If electro-mechanical buzzers are used anywhere on the vehicle, it is desirable to have the entire PEEC system (ECM, Throttle Position Sensor, Vehicle Speed Buffer, and Check Engine Lamp) powered directly from the battery system through a dedicated relay, and not through a common power bus with other key switch activated devices.

For schematics of the PEEC system, see Electrical Schematics, Form No. SENR3486.

Electronic Control Module Power Circuit

The design of the electronic circuits inside the Electronic Control Module (ECM) are such that the ordinary switch input circuits to the ECM (cruise control on/off switch, brake switch, etc.) have a tolerance for resistance and shorts between wires. These tolerances are as follows:

1. PEEC will tolerate resistance in any ordinary switch up to 2.5 Ohms without malfunctioning.

2. PEEC will tolerate shorts to ground or between wires in any ordinary switch input down to 5,000 Ohms without malfunctioning.

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NOTICE

The +12 Volt wire in the data link harness of the ECM is provided to power the PEEC service tools only. No other devices should be powered by this wire. The ECM was not designed to carry high current loads and is not short circuit protected.

The ECM draws a maximum of 7.5 Amps at 12 Volts from the electrical system of the vehicle. However, PEEC will function with less than 12 Volts. A minimum of 9 Volts is required while cranking, and 11 Volts when the engine is running.

Power enters the ECM through the positive BATTERY wire, and exits through the negative BATTERY wire. Negative BATTERY must be within .5 Volt of vehicle frame ground.

PEEC is protected against power surges on the 12 Volt power supply due to alternator load dumps, air conditioner clutches, etc., and for jump starting with voltages up to 28 Volts.

Engine Speed Input Circuit

Engine speed is sensed by an electronic engine speed sensor. It is similar to electro-magnetic pickups with which you may already be familiar; that is, the signal is generated by placing the sensor near a rotating component, but it is different in that it requires an operating voltage. The engine speed sensor is provided an operating voltage of 8.0 ± .4 Volts by the ECM.

The output of the engine speed sensor is a voltage pulse whose frequency is dependent on the speed of the engine. The frequency of the pulse is interpreted by the ECM as engine speed. Typically the frequency of this signal is 10 to 50 Hz (Hertz) while cranking, and approximately 120 Hz at low idle.

Fuel Rack Input Circuit

The engine fuel rack signal is obtained from an electronic linear position sensor which follows the movement of the rack assembly. This sensor requires an operating voltage of 8.0 ± .4 Volts, and a reference voltage of 5.0 ± .25 Volts. These voltages are provided by the ECM.

The output of the Rack Position Sensor is a voltage between .3 and 5.25 Volts. This voltage is dependent upon the position of the Rack Position Sensor, and is interpreted by the ECM as rack position.

Timing Advance Input Circuit

Engine timing is obtained from an electronic linear position sensor which follows movement of the variable timing advance unit (fuel pump drive group). This sensor is very similar to, but not the same as, the one used to read rack position. It also requires an operating voltage of 8.0 ± .4 Volts, and a reference voltage of 5.0 ± .25 Volts. These voltages are provided by the ECM.

The timing position sensor output is a voltage between .3 and 5.25 Volts. This voltage is dependent upon the position of the timing position sensor, and is interpreted by the ECM as the timing advance angle.

Boost Pressure Input Circuit

The Boost Pressure Sensor is located in the Transducer Module. Air from the engine inlet manifold is routed to this sensor. This sensor requires an operating voltage of 8.0 ± .4 Volts, and a reference voltage of 5.0 ± .25 Volts.

The output of the Boost Pressure Sensor is a DC voltage of .8 to 5.0 Volts. This voltage is dependent upon the pressure felt by the Boost Pressure Sensor, and is interpreted by the ECM as engine boost pressure (gauge).

Engine Oil Pressure Input Circuit

The engine Oil Pressure Sensor is also located in the Transducer Module. Engine oil pressure from the fuel injection pump is routed to this sensor. This sensor also requires an operating voltage of 8 Volts, and a reference voltage of 5 Volts.

The output of the Oil Pressure Sensor is a DC voltage of 1.8 to 5.3 Volts. This voltage is dependent upon engine oil pressure and is interpreted by the ECM as oil pressure.

The PEEC Oil Pressure Sensor is designed to measure engine oil pressure between 0 and 312 kPa (0 and 45 psi). Engine oil pressures greater than 312 kPa (45 psi) are read as 312 kPa (45 psi). This limited oil pressure reading range provides more accurate low oil pressure readings (where oil pressure readings are most important) than a sensor capable of reading the maximum engine oil pressure.

Throttle Position Input Circuit

Throttle position is obtained from an electronic sensor connected to the accelerator pedal. The 12 Volts operating voltage is provided to the sensor by the vehicle electrical system.

The output of the Throttle Position Sensor is a constant frequency signal with voltage levels of 0 or 5 Volts. The Pulse Width, (not the frequency) of the signal is dependent upon the arm rotation of the Throttle Position Sensor and is interpreted by the ECM as throttle position. The ECM interprets the minimum Pulse Width it sees (between 15% and 20%) as 3% throttle position and the maximum Pulse Width it sees (between 80% and 85%) as 100% throttle position.

The arm on the Throttle Position Sensor has a maximum rotation of 45 degrees. The ECM only responds to a 30 degree active zone for interpreting the throttle position. The Throttle Position Sensor has a 5 degree lead in dead zone, a 30 degree active zone, and a 10 degree lead out zone. Mechanical stops on the accelerator pedal or the pedal linkage should restrict the throttle sensor rotation to within the active zone.

Vehicle Speed Input Circuit

Vehicle speed is obtained from an ordinary electro-magnetic sensor reacting to the rotation of gear teeth in the drive train of the vehicle. It is provided by the vehicle manufacturer.

The output of the Vehicle Speed Sensor is an AC voltage, and could be as much as 50 or 60 Volts. The signal is sent to the Vehicle Speed Buffer where it is modified and split into two separate and distinctly different signals... one for PEEC, and one for use by the vehicle manufacturer. The PEEC signal is a pulsed DC voltage of 0 to 6 Volts. It is sent to the control module and interpreted as vehicle speed. The other is an AC voltage of -3.0 to +2.5 Volts.

An operating voltage of 12 Volts is required by the buffer and is provided by the vehicle electrical system.

Cruise Control ON/OFF Input Circuit

The Cruise Control (CC) and Power Take Off (PTO) ON/OFF input is provided by an ordinary switch. Placing the ON/OFF switch in the ON position makes it possible for the Cruise Control or PTO Mode to be made active, if the speed is within the range programmed into the ECM for the mode.

With this switch "open" (or OFF), the input line to the ECM will go to approximately 5 volts. With the switch "closed" (or ON), the input line to the ECM will go to 0 volts (ground).

Cruise Control SET/RESUME Input Circuit

The Cruise Control (CC) and Power Take Off (PTO) SET/RESUME input is provided by a three position switch. The switch is used to set vehicle speed or engine speed. The purpose of each position of the switch is as follows:

1) In the center position the SET/RESUME switch is open, and the input is inactive.

2) If the switch is moved to the SET position and released the ECM will maintain the speed existing when the switch was released. If the switch is held in the SET position the ECM will gradually increase the speed and the setting until the switch is released.

3) If cruise is deactivated by application of the clutch or brake, and the switch is moved to the RESUME position and released, the mode is reactivated to the last setting. If the switch is held in the RESUME position the ECM will gradually decrease the speed and the setting until the switch is released.

With this switch "open" (or OFF), the input line to the ECM will go to approximately 5 volts. With the switch "closed" (or ON), the input line to the ECM will go to 0 volts (ground).

Cruise Control Brake/Clutch Input Circuit

The Cruise Control (CC) and Power Take Off (PTO) BRAKE/CLUTCH input is provided by two ordinary switches in series. When PEEC is operating in either the cruise control or power take off mode, the opening of either switch by the application of either the clutch or the brake, deactivates the cruise control or PTO mode.

With this switch "open" (or OFF), the input line to the ECM will go to approximately 5 volts. With the switch "closed" (or ON), the input line to the ECM will go to 0 volts (ground).

Shutoff Solenoid Output Circuit

The shutoff solenoid is an output component of PEEC that must be energized for the engine to run. The ECM supplies battery voltage directly to the solenoid through the CRANK input while the engine is being cranked. This eliminates the possibility of a voltage drop across the PEEC control large enough to prevent the shutoff solenoid from being fully powered.

The output of the ECM module to the shutoff solenoid is a pulsed voltage that can reach up to 6 Volts for about one-half second after the ignition switch is turned ON for the purpose of pulling in the solenoid, and then drops off to approximately 1.7 Volts to hold the solenoid in.

The PEEC system is designed to continue operation of the engine with as many faults as possible. There are four faults which will de-energize the shutoff solenoid and shut down the engine. These are as follows:

* Loss of Engine Speed Signal.* An Engine Speed Signal of 2300 rpm or greater.* A faulty shutoff solenoid.* Loss of electrical power to the ECM.

Fuel Rack Output Circuit

Movement of the engine fuel rack is accomplished by PEEC with an output component known as a Rack Solenoid (BTM).

The Rack Solenoid (BTM) is a device whose movement is proportional to the electrical current flowing through it. The ECM provides a pulsed voltage of 0 to 3.6 Volts to the Rack Solenoid (BTM).

The Rack Solenoid (BTM) moves the engine fuel rack through the movement of the governor servo spool valve and hydraulic pressure.

The PEEC has a built-in operational test for the Rack Solenoid (BTM). This test is accomplished as follows:

1. Remove the Rack Solenoid (BTM) from its housing.

2. Position it so that the arm of the solenoid is free to move.

3. Turn the ignition switch ON.

4. Turn the Cruise Control Switch ON.

5. Move the SET/RESUME Switch to the SET position and release it.

The expected results of this test are that after about 5 seconds the solenoid arm will sweep to the full ON position, remain there a few seconds, and then sweep back to the OFF position. Sweep time will be about 5 seconds in both directions.

Engine Timing Output Circuit

The engine timing advance unit is activated by the PEEC using a Timing Solenoid (BTM). Movement of the timing advance unit is accomplished through movement of the timing advance spool valve and hydraulic pressure.

The Timing Solenoid (BTM) is identical to the one used by the ECM to position the fuel rack. The ECM sends a pulsed voltage of 0 to 3.6 Volts to the Timing Solenoid (BTM).

The PEEC has a built-in operational test for the Timing Solenoid (BTM). This test is accomplished as follows:

1. Remove the timing solenoid from its housing.

2. Position it so that the arm of the solenoid is free to move.

3. Turn the ignition switch ON.

4. Turn the Cruise Control Switch ON.

5. Move the SET/RESUME Switch to the RESUME position and release it.

Check Engine Light (Diagnostic) Output Circuit

The engine/vehicle harness provides information about the engine to the "check engine" light on the vehicle dash. The light flashes Diagnostic Code 34 when the ignition is ON and the engine is not running, to verify that the light works. When the engine is started the light will be ON solid until the PEEC system senses a minimum of 35 kPa (5 psi) oil pressure. If the engine light does not go out after the engine starts the light will begin to flash the Diagnostic Codes that are active in the PEEC System.

The cruise ON/OFF and SET/RESUME switches can be used to interrogate the ECM for engine status. This is accomplished by placing the cruise ON/OFF switch in the OFF position and momentarily moving the Set/Resume switch to the RESUME position and then releasing it. The "check engine" light will emit a series of flashes which represent one or more, two digit numbers or diagnostic codes, which define engine status.

An operating voltage of 12 Volts is supplied to the "check engine" light from the vehicle electrical system. The ECM turns on the light by connecting one side of the bulb to ground which completes the electrical circuit.

Engine Electrical System

The electrical system can have three separate circuits: the charging circuit, the starting circuit and the low amperage circuit. Some of the electrical system components are used in more than one circuit. The battery (batteries), circuit breaker, ammeter, cables and wires from the battery are all common in each of the circuits.

The charging circuit is in operation when the engine is running. An alternator makes electricity for the charging circuit. A voltage regulator in the circuit controls the electrical output to keep the battery at full charge.

The starting circuit is in operation only when the start switch is activated.

The low amperage circuit and the charging circuit are both connected through the ammeter. The starting circuit is not connected through the ammeter.

Charging System Components

Alternator

The alternator is driven by V-type belts from the crankshaft pulley. This alternator is a three phase, self-rectifying charging unit, and the regulator is part of the alternator.

This alternator design has no need for slip rings or brushes, and the only part that has movement is the rotor assembly. All conductors that carry current are stationary. The conductors are: the field winding, stator windings, six rectifying diodes, and the regulator circuit components.

The rotor assembly has many magnetic poles like fingers with air space between each opposite pole. The poles have residual magnetism (like permanent magnets) that produce a small amount of magnet-like lines of force (magnetic field) between the poles. As the rotor assembly begins to turn between the field winding and the stator windings, a small amount of alternating current (AC) is produced in the stator windings from the small magnetic lines of force made by the residual magnetism of the poles. This AC current is changed to direct current (DC) when it passes through the diodes of the rectifier bridge. Most of this current goes to charge the battery and to supply the low amperage circuit, and the remainder is sent on to the field windings. The DC current flow through the field windings (wires around an iron core) now increases the strength of the magnetic lines of force. These stronger lines of force now increase the amount of AC current produced in the stator windings. The increased speed of the rotor assembly also increases the current and voltage output of the alternator.

The voltage regulator is a solid state (transistor, stationary parts) electronic switch. It feels the voltage in the system and switches on and off many times a second to control the field current (DC current to the field windings) for the alternator to make the needed voltage output.

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NOTICE

Never operate the alternator without the battery in the circuit. Making or breaking an alternator connection with heavy load on the circuit can cause damage to the regulator.

Alternator Components
(1) Regulator. (2) Roller bearing. (3) Stator winding. (4) Ball bearing. (5) Rectifier bridge. (6) Field winding. (7) Rotor assembly. (8) Fan.

Starting System Components

Solenoid

Typical Solenoid Schematic

A solenoid is an electromagnetic switch that does two basic operations.

a. Closes the high current starter motor circuit with a low current start switch circuit.

b. Engages the starter motor pinion with the ring gear.

The solenoid has windings (one or two sets) around a hollow cylinder. There is a plunger (core) with a spring load inside the cylinder that can move forward and backward. When the start switch is closed and electricity is sent through the windings, a magnetic field is made that pulls the plunger forward in the cylinder. This moves the shift lever (connected to the rear of the plunger) to engage the pinion drive gear with the ring gear. The front end of the plunger then makes contact across the battery and motor terminals of the solenoid, and the starter motor begins to turn the flywheel of the engine.

When the start switch is opened, current no longer flows through the windings. The spring now pushes the plunger back to the original position, and at the same time, moves the pinion gear away from the flywheel.

When two sets of windings in the solenoid are used, they are called the hold-in winding and the pull-in winding. Both have the same number of turns around the cylinder, but the pull-in winding uses a larger diameter wire to produce a greater magnetic field. When the start switch is closed, part of the current flows from the battery through the hold-in winding, and the rest flows through the pull-in windings to motor terminal, then through the motor to ground. When the solenoid is fully activated (connection across battery and motor terminal is complete), current is shut off through the pull-in windings. Now only the smaller hold-in windings are in operation for the extended period of time it takes to start the engine. The solenoid will now take less current from the battery, and heat made by the solenoid will be kept at an acceptable level.

Starter Motor

The starter motor is used to turn the engine flywheel fast enough to get the engine to start running.

The starter motor has a solenoid. When the start switch is activated, the solenoid will move the starter pinion to engage it with the ring gear on the flywheel of the engine. The starter pinion will engage with the ring gear before the electric contacts in the solenoid close the circuit between the battery and the starter motor. When the circuit between the battery and the starter motor is complete, the pinion will turn the engine flywheel. A clutch gives protection for the starter motor so that the engine can not turn the starter motor too fast. When the start switch is released, the starter pinion will move away from the ring gear.

Starter Motor Cross Section
(1) Field. (2) Solenoid. (3) Clutch. (4) Pinion. (5) Commutator. (6) Brush Assembly. (7) Armature.

Wiring Diagrams For Grounded Electrical Systems

These systems are used in applications when it is not necessary to prevent radio distortion and/or chemical changes (electrolysis) of grounded components.

(Regulator Inside Alternator)

Charging System With Electric Starter Motor
(1) Start switch. (2) Ammeter. (3) Alternator. (4) Battery. (5) Starter motor.

Wiring Diagrams For Insulated Electrical Systems

These systems are most often used in applications where radio interference is not desired or where conditions are such that grounded components will have corrosion from chemical change (electrolysis).