GEAR-PLANETARY 7G3463 - Caterpillar

Control System
The following components are included in the control system:
An Electronic Control Module (ECM) and an emergency stop button in an engine mounted junction box
Optional remote control panel with either a Machine Information Display System (MIDS) or an Advisor monitor display
Integrated Combustion Sensing Module (ICSM)
Gas Shutoff Valve (GSOV)
Ignition system that is controlled by the ECM
Detonation sensor for each two cylinders
A system for prelube or postlube that includes the solenoid and prelube pump
Actuators that are hydraulically actuated and electronically controlled for the fuel, for the air choke, and for the exhaust bypass (wastegate)
A system for cranking that includes the solenoid and starting motorThe ECM controls most of the functions of the engine. The module is an environmentally sealed unit that is in an engine mounted junction box. The ECM monitors various inputs from sensors in order to activate relays, solenoids, etc at the appropriate levels. The ECM supports the following five primary functions:
Governing of the engine
Control of ignition
Air/fuel ratio control
Start/stop control
Monitoring of engine operationThe ECM does not have a removable personality module. The software and maps are changed with Caterpillar Electronic Technician (ET) by flash programming of a file.Governing of the Engine RPM
Desired engine speed is determined by the status of the idle/rated switch, of the desired speed input (analog voltage or 4 to 20 mA), and of parameters that are programmed into the software. Actual engine speed is detected via a signal from the engine speed/timing sensor. Parameters such as idle speed and governor gain can be programmed with Cat ET.The ECM monitors the actual engine speed. The ECM calculates the difference between the actual engine speed and the desired engine speed. The ECM controls the fuel actuator in order to maintain the desired engine speed. The fuel actuator is located at the flange of the inlet air manifold.If the actual engine speed is less than the desired engine speed, the ECM commands the fuel actuator to move toward the open position in order to increase the fuel flow. The increase of fuel accelerates the engine speed.Control of Ignition
Each cylinder has an ignition transformer. To initiate combustion, the ECM sends a pulse of approximately 108 volts to the primary coil of each ignition transformer at the appropriate time and for the appropriate duration. The transformer increases the voltage which creates a spark across the spark plug electrode.The ECM provides variable ignition timing that is sensitive to detonation. Detonation sensors monitor the engine for excessive detonation. The engine has one detonation sensor for each two adjacent cylinders. The sensors generate data on vibration that is processed by the ECM in order to determine detonation levels. If detonation reaches an unacceptable level, the ECM retards the ignition timing of the affected cylinder or cylinders. If retarding the timing does not limit detonation to an acceptable level, the ECM shuts down the engine.Levels of detonation can be displayed by the Machine Information Display System (MIDS) or by the Advisor display on the optional control panel. Alternatively, the "Cylinder X Detonation Level"