EDGE-CUTTING 9W3927 - Caterpillar

The Electronic Control Module (ECM) provides control of the air/fuel mixture for performance and for efficiency at low emission levels. The system includes the following components:
Maps in the ECM
Output drivers in the ECM
Fuel metering valve
Air inlet pressure sensor
Inlet manifold air temperature sensor
Engine speed/timing sensor
Generator output power sensor
Throttle differential pressure sensor
Compressor outlet pressure sensor
Compressor outlet temperature sensorAdditionally, the customer input via the Caterpillar Electronic Technician (Cat ET) is required. Refer to Illustration 1 for a diagram of the main components and inputs for the system.
Illustration 1 g02191453
Diagram of the air/fuel ratio control
Throttle differential pressure sensor - This sensor monitors the pressure drop across the throttle valve.Compressor outlet pressure sensor - This sensor monitors the pressure of the air/fuel mixture from the turbocharger compressor outlet.Compressor outlet temperature sensor - This sensor monitors the temperature of the air/fuel mixture from the turbocharger compressor outlet.Cat ET - This software is designed to run on a personal computer. Technicians can use the program to perform many functions. For the air/fuel ratio control, the technician programs configuration parameters into the ECM.Generator output power sensor - The engine control system requires an input which indicates the generator output in kilowatts. This input can be from a programmable logic controller (PLC), or from a wattmeter. The equipment that monitors the generator output is provided by the customer. The PLC or the wattmeter must provide an analog signal with a range of 0 to 5 VDC. The signal must use as much of this range as possible. The signal must be accurate within 0.5 percent of the actual output of the generator. The signal must have a linear relationship with the actual output of the generator in electrical kilowatts (ekW).Inlet manifold air temperature sensor - This sensor monitors the temperature of the air/fuel mixture in the inlet manifold.Air inlet pressure sensor - This sensor monitors the pressure of the air/fuel mixture in the inlet manifold.Engine speed/timing sensor - This sensor monitors the rotation of a speed-timing wheel in order to provide information on the engine timing and on the engine rpm.Fuel metering valve - This valve is an electronically controlled actuator and a valve that regulates the flow of fuel. The device monitors the fuel temperature, the fuel pressure, and the differential pressure across the valve. The ECM sends a command signal for the fuel flow to the device. The device modulates the valve in order to match the command signal. The ECM communicates with the fuel metering valve via the CAN data link.Optional Fuel Quality Sensor - Some applications support an input for remote fuel quality. These engines can accept an input from a fuel quality sensor that is provided by the customer. The sensor performs continuous analysis of the fuel in order to determine the LHV for the fuel. The sensor provides a 4 to 20 mA signal to the ECM which indicates the LHV for the fuel. The sensor has a "CONFIG" setting and a "4 to 20 mA" setting. The "CONFIG" setting is used