3E0-77193-0 Tohatsu OIL SEAL

Illustration 1 g01443064
Diagram of the air/fuel ratio control
The engine is not equipped with an ASM.
Illustration 2 g01443066
Diagram of the air/fuel ratio control
The engine is equipped with an ASM.
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 the EMCP II+, from a programmable logic controller (PLC), or from a wattmeter. If the EMCP II+ is not used, 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 generator actual output. The signal must have a linear relationship with the generator actual output in electrical kilowatts (ekW). Engines that are equipped with ASM are not compatible with EMCP II+ load signal.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 - The 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 valve differential pressure. 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 fuel LHV. The sensor provides a 4 to 20 mA signal to the ECM which indicates the fuel LHV. The sensor has a "CONFIG" setting and a "4 to 20 mA" setting. The "CONFIG" setting is only used if the quality of fuel supply is constant. The "4 to 20 mA" setting is used when the quality of the fuel supply is variable.The air/fuel ratio control has two basic modes of operation:
Open loop
Charge density feedbackThe modes of operation are explained below.For proper operation of the air/fuel ratio control, inputs from the customer are necessary.Inputs from the Customer
To control the air/fuel ratio, the control system depends on these inputs from the customer:
Fuel Quality
Engine LoadFuel Quality
Before the initial start-up, a current gas analysis is required. Data from the gas analysis must be entered into Caterpillar Software, LERW4485, "Gas Engine Rating Pro (GERP)". The results are programmed into the ECM.Note: Use the Caterpillar Software, LERW4485, "Gas Engine Rating Pro (GERP)". Use of only the data from the gas analysis can result in incorrect settings.The ECM must have values for the following parameters. The values are entered via the "Configuration" screen of Cat ET:
"Fuel Quality Input Type Configuration"
"Fuel Quality Sensor LHV Lower Setpoint"
"Fuel Quality Sensor LHV Upper Setpoint"
"Fuel Quality"
"Gas Specific Gravity"
"Fuel Specific Heat Ratio"Note: The "Fuel Quality Sensor LHV Lower Setpoint" and the "Fuel Quality Sensor LHV Upper Setpoint" are needed only when using the 4-20 mA signal from a fuel quality sensor.Note: For more details on these parameters, refer to Systems Operation/Testing and Adjusting, "Electronic Control System Parameters"."Fuel Quality Input Type Configuration" - Program this parameter to either "CONFIG" or "4 to 20 mA". The "CONFIG" setting is only used if the quality of fuel supply is constant. If the "CONFIG" setting is used, enter a value under the "Fuel Quality" setting. The "4 to 20 mA" setting is used when the quality of the fuel supply is variable. If the "4 to 20 mA" is used, enter the values for the "Fuel Quality Sensor LHV Lower Setpoint" and for the "Fuel Quality Sensor LHV Upper Setpoint"."Fuel Quality Sensor LHV Lower Setpoint" - The ECM uses the value of this parameter to determine the lower limit of the range of the fuel LHV."Fuel Quality Sensor LHV Upper Setpoint" - The ECM uses the value of this parameter to help determine the upper limit of the range of the fuel LHV."Fuel Quality" - This parameter is the fuel Low Heating Value (LHV). The value is obtained from a fuel analysis which is entered into Caterpillar Software, LERW4485, "Gas Engine Rating Pro (GERP)". Only use this value when the fuel quality sensor is in the "CONFIG" setting.During operation, the ECM uses the LHV to help determine the command signal for the fuel flow."Gas Specific Gravity" - This parameter is the fuel-specific gravity in relation to the specific gravity of air. The value is obtained from a fuel analysis which is entered into Caterpillar Software, LERW4485, "Gas Engine Rating Pro (GERP)"."Fuel Specific Heat Ratio" - This parameter is a ratio of the fuel-specific heat at a constant pressure and at a constant volume.The ECM provides the fuel-specific gravity and heat ratio to the fuel metering valve via the CAN data link. The fuel metering valve uses this information to help regulate the fuel flow.In addition to the information on the fuel, the ECM requires information on the engine load.Engine Load
The ECM must have values for the following parameters. The parameters are entered into the ECM via Cat ET.
"Engine Output Power"
"Engine Driven Accessory Load Configuration"
"Generator Output Power Sensor Scale Factor"
"Generator Output Power Sensor Offset""Engine Output Power" - This parameter is the engine full load rating in ekW. The rating is stamped on the engine Information Plate. During engine operation, the ECM uses this value to determine the engine load as a percentage of