PLUG-DRAIN 4729199 - Caterpillar

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The rear view of the Bosch VP30 fuel injection pump (7) Fuel solenoid valve (12) Delivery valve (15) Control valve for the advance and for the retarding The distribution of fuel to the injectors takes place through the rotating movement of the distributor plunger. The fuel solenoid valve (7) meters the amount of fuel by the following operations:
Time of closure
Duration time
Start of injection
Amount of fuel
Illustration 10 g00897417
The delivery of fuel from the delivery valve for the Bosch VP30 fuel injection pump
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The closing of the delivery valve for the Bosch VP30 fuel injection pumpThe delivery valve ensures that the pressure waves do not allow a reopening of the injector . The pressure waves are created at the end of the injection process. The valve cone is lifted by the fuel pressure. The fuel is forced through the fuel line to the injector. The delivery ends and the fuel pressure drops. The valve spring presses the valve cone onto the valve seat. The reopening of a fuel injector has a negative effect on emissions.Timing
Retarding of the fuel injection is the direct relationship between the start of injection and the position of the piston. The timing compensates for the higher RPM of the engine by advancing the start of injection.
Illustration 12 g01302233
Timing mechanism for the Bosch VP30 High-pressure fuel (30) in the fuel injection pump pushes the piston (31) against the spring pressure. This advances the timing. The control valve (15) is closed. When a PWM signal is sent to the control valve, the needle of the control valve releases the internal pressure to the low-pressure side (32) . This retards the timing. The duty cycle of the PWM signal is proportional to the amount of retardation.The mechanical influence on the piston movement is control by an orifice in the piston. This also prevents a large internal pressure drop when the control valve is open.Shutoff
The engine shuts off by interrupting the fuel supply. The engine electronic control module (ECM) specifies the amount of fuel. The fuel solenoid valve is switched by the ECU (2) to zero.Control
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Electronic control for the fuel system (typical example)The ECU for the injection pump (2) uses the command from the ECM and the measured values from the speed/timing sensor to actuate the fuel solenoid valve (7) .
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The wheel and the speed/timing sensor for the Bosch VP30 (5) Speed/timing sensor (23) Timing wheelThe ECU for the injection pump (2) is mounted on the top of the pump. The ECU (2) has a connection to the engine ECM and a connection to the speed/timing sensor (5) . ECU (2) has a connection for the two solenoid operated control valves. The ECM functions as a control computer. The ECU (2) calculates the optimal parameters from the ECM data. The fuel solenoid actuates the valve accordingly.The speed/timing sensor (5) in the fuel injection pump determines the precise angular position and the speed of the fuel