卡特C9发动机技术2

•24 Volt power supply•Power supply components•Power supplydiagnostic messageECM Power SupplyThe power supply to the ECM and the system is provided by the 24 V olt machine battery. The principle components in this circuit are:- Battery- Key Start Switch - Main Power Relay - 20 Amp Breaker - 20 Amp Fuse - Ground Bolt- ECM Connector (P1/JI)If the supply voltage exceeds 32.5 V olts or is less than 9.0 V olts, a diagnostic message is logged. (See the Troubleshooting Guide for complete details on voltage event logging.)•ECM power supply circuit•ECM switched connection- Energizes ECM•Battery disconnect switch The battery disconnect may be either on the positive or the negative cable depending on the application. The relevant Troubleshooting Guide will show the location of the switch.The machine wiring harness can be bypassed for troubleshooting purposes. These steps are described in the Troubleshooting Guide procedure. A breakout harness can be used and is referenced under "C-9 Recommended Tooling" at the front of this book.The supply voltage may be conveniently checked using the ET Status Screen display.NOTE 1: The Challenger Tractor engine and some industrial engines may have a 12 V olt power supply.NOTE 2:The Wire Function Color Code is shown here for the first time and is used through the presentation.•P1/P2 70 pin ECM connectors•P1/J1 machineinterface connectorThere are two 70 pin connectors which identify the ADEM III ECM. The previous ADEM II ECM used a pair of 40 pin connectors.The 70 pin ECM connectors are vital parts of all the power supplies (and sensor circuits). This illustration shows one of the two ECM 70 pin connectors, P1. The pins highlighted in this connector are for the ECM power supply circuit.The C-9 Engine does not have a separate machine interface connector.The P1/J1 connector performs this function and transmits the power supply from the machine wiring to the engine wiring harnesses. The Troubleshooting Guide identifies the relevant pins for each circuit in this manner. This feature greatly simplifies troubleshooting by easily identifying the connections in the circuit.•70 volt power supply•Power supply wires are paired•Injectors and brake solenoids areswitched on return sideInjector and Compression Brake Power SupplyThe injector and compression brake solenoids are supplied with power from the ECM at 70 V olts. For this reason, precautions must be observed when performing maintenance around the valve covers.If an open or a short circuit occurs in an injector or compression brake component, the ECM will disable that circuit. The ECM will periodically try to actuate that circuit to determine if the fault is still present and will disconnect or reconnect the injector/compression brake as appropriate.The power supply wires are paired for each injector and brake solenoid.Individual return circuits are provided which contain the solenoid drivers. NOTE: If an injector is replaced, it must be calibrated. Also if an ECM is replaced and injector calibration or copy configuration is not performed, a fault message will be generated. (The CopyConfiguration function will transfer all calibrations to the new ECM.)•Pump control valve signal•System tested using ETHydraulic Pump Control Valve Power SupplyThe ECM supplies a PWM signal through the J2/P2 connector to the Pump Control Valve (also known as the injection actuation pressure control valve).The Pump Control Valve and its power supply can be tested on the engine using ET and the Hydraulic Injection Actuation Pressure Test. Using the test, the pressure can be adjusted manually with the ET service tool from minimum to maximum. Therefore, this function can be used to verify the operation of the control valve, the power supply from the ECM, and the hydraulic system.There is no voltage specification for the Pump Control Valve Power Supply. Current flow may vary between 250 and 1000 mA.•Analog power supply•Four power supply terminals•Power supply protection •Analog returnAnalog Sensor Power SupplyThe Analog Sensor Power Supply provides power to all the active analog sensors (pressure and temperature sensors). The ECM supplies 5.0 ±0.5V olts DC (Analog Supply) through the J2/P2 connector to each sensor. A power supply failure will cause all active analog sensors to fail. This failure could be caused by a short in a sensor. An open circuit in the common lines close to the P2/J2 connector can also cause multiplefailures. Unlike previous EUI/HEUI engines, the C-9 uses four individual ECM analog power connections from the J1/P1 connector (two supply and two return).The Analog Sensor Power Supply is protected against short circuits. A short in a sensor or a wiring harness will not cause damage to the ECM. NOTE: When checking the analog power supply voltage, always use the analog return for the measurement and not the frame ground. A difference can occur between the measurements of analog power supply and system voltage. The analog power supply is held to close tolerances.•Digital power supply•Power supply protection•Digital power supply voltage check •Digital returnDigital Sensor Power SupplyThe ECM supplies power at 8 ±0.5 V olts through the J1/P1 connector to the Throttle Position Sensor circuit.Like the Analog power supply, this circuit is protected against short circuits, which means that a short in the sensor will not cause damage to the ECM.Some other C-9 applications may use this power supply to power fan speed or exhaust temperature sensors for example.NOTE: It is necessary when checking this system power supply voltage to use the digital return for the measurement and not the frame ground. A difference between these values can occur if an incorrect ground is used.•Uses coolant and intake temperature sensors as references •Modes of operationAir Intake HeaterThe Air Intake Heater is used to improve the cold start ability of the engine.The heater is controlled by the ECM using inputs from the Air Intake Temperature and Coolant Temperature Sensors. The ECM sends a signal to the relay which controls the supply of current to the heater element. There are a various modes of operation depending on temperatures and other conditions. These parameters and the defaults are fully described in the C-9 Troubleshooting Guide and later in this presentation in the section "Electronic Sensors and Systems."•Communication adapter uses power from ECM•Circuit is energized with the keyswitchService Tool Power SupplyIn the past, the ECAP (Electronic Analyzer Programmer) Service Tool drew it's power from the Service Tool Connector. In the same way, when using ET, the Communicator Adapter II also requires a power supply, this power is taken from pins A and B on the Service Tool Connector. This illustration shows the path of the current from the ECM to theService Tool Connector. This power supply requires the engine keyswitch to be ON.Pin 70 on the J1/P1 connector, is the same terminal which is used by the Keyswitch to turn on the ECM.•Lab exercise INSTRUCTOR NOTE: The following exercises will reinforce the material introduced in the preceding pages and will allow questions to be answered.Lab Exercise:Remove and install the following components on an engine in accordance with service manual procedures:Pressure sensorTemperature sensorThrottle position sensorSpeed/timing sensorsECMTest the following power supply circuits on an engine in accordance with the appropriate service manual procedures:ECM power supplyHEUI pump control valve power supplyAnalog sensor power supplyDigital sensor power supplyIntake heater power supplyService tool power supply。