5033471 JOHNSON BOLT (6X28mm)

Illustration 1 g00905951
Schematic of the air/fuel ratio control's governing system
(1) Customer supplied input for desired speed
(2) Analog to digital converter
(3) ECM
(4) EGP3 Actuator
(5) Engine speed sensor
(6) Manifold air pressure sensor
(7) Idle/rated switch
(8) Five PWM to analog converters
(9) Caterpillar Electronic Technician (Cat ET)
(10) Digital Diagnostic Tool (DDT) Note: The input for the desired speed can be supplied by an idle/rated switch, a speed potentiometer, a pressure module, or a source of 4 to 20 mA.Pulse Width Modulation (PWM) - This is a digital signal. The frequency is constant: the widths of the signal's pulses are varied within a fixed interval (frequency). The variable widths are also called a duty cycle. The variable widths enable the signal to be interpreted as a range of values. This provides a more accurate status for a parameter than a signal that can only be ON or OFF.
Illustration 2 g00852792
Example of a PWM signal
The desired engine speed is determined by a customer supplied input (1) or by idle/rated switch (7). If the speed potentiometer is used, the analog signal is converted into a PWM signal by converter (2). The PWM signal goes to the desired speed input in ECM (3). The ECM is located in a remote panel.The range of the desired speed is determined by the programmable parameters. The programming is performed with the Cat ET (9) or with a DDT (10). For information on the programmable parameters, refer to Systems Operation, "Electronic Control System Parameters".The engine speed is detected by engine speed sensor (5) (magnetic pickup) that is installed in the flywheel housing. The inlet manifold air pressure is monitored by manifold air pressure sensor (6). The sensors send the information to the ECM.The ECM monitors the inlet manifold air pressure in order to calculate the load. The load is a factor for adjusting the governor's gain, stability, and compensation.The ECM converts the signal from the engine speed sensor into the actual engine speed. The actual engine speed is compared to the desired engine speed.If the actual engine speed does not match the desired engine speed, the ECM sends a throttle command to actuator (4). The actuator moves the linkage that is connected to the throttle.The remote panel may have five converters (8) that can provide information on engine status to the customer's instruments. The PWM signals from the ECM are converted into analog voltage. The information can be provided for these parameters: inlet manifold air pressure, inlet manifold air temperature, ignition timing, percent of exhaust oxygen and engine speed.Electronic Governors
For engines without the air/fuel ratio control, a variety of electronic governors are available for use. The electronic governors operate similarly.The engine speed is detected by an engine speed sensor (magnetic pickup) that is installed in the flywheel housing. The sensor generates AC voltage that is sent to the governor. The governor sends DC voltage to an actuator. The actuator converts the electrical input into a mechanical output. The actuator moves the linkage that is connected to the throttle plate in order to adjust the engine speed.If the engine speed is greater than the speed setting, the governor reduces the output to the actuator. If the engine speed is less than the speed setting, the governor increases the output to the actuator.For detailed information on electronic governors, refer to the literature for your specific equipment.EG-3P Actuator
Illustration 3 g01046906
EG-3P Actuator
The EG-3P Actuator is a hydraulic actuator. The actuator's hydraulic oil supply is provided by engine's oil. The actuator's hydraulic oil pressure is provided by an internal oil pump that is located within the actuator. An accessory drive group on the engine drives the oil pump. An electronic governor sends a signal to the actuator. The actuator converts the electronic signal into hydraulic pressure. The hydraulic pressure moves the mechanical linkage that is attached to the throttle plate.Refer to the following service manuals for further information:
Service Manual, SENR2928, "2301 Electric Governor"
Service Manual, SENR3585, "2301A Electric Governor"
Service Manual, SENR4676, "2301A Electric Governor"ProAct Actuator
Illustration 4 g01046905
ProAct actuator
Illustration 5 g01050380
ProAct integrated throttle body actuator
The ProAct actuator is an electronic actuator. The throttle plate is driven directly by the actuator. Input to the actuator is provided by an electronic governor.Refer to Service Manual, SENR1196, "ProAct Digital Speed Control" and refer to Operation and Calibration Manual, RENR5917, "Woodward ProAct II Electric Powered Actuator and Driver" for further information.3161 Governor
Illustration 6 g00805672
3161 Governor
The 3161 Governor is a hydromechanical governor. The governor linkage is attached to the throttle plate. The governor's hydraulic pressure is provided by the governor's own supply of oil. This hydraulic pressure is used to move the terminal shaft. The governor's droop and compensation can be adjusted in order to accommodate individual installations.Refer to Systems Operation/Testing and Adjusting, SENR3028, "Caterpillar 3161 Governor" for further information.