Perkins 1104D NH1 Systems Operation Testing And Adjusting page 26

26
Systems Operation Section
The fuel transfer pump provides a relatively low fuel
pressure to the fuel injection pump. The fuel transfer
pump has a regulating valve in order to control the
low pressure. The fuel transfer pump circulates fuel
through the primary fuel filter and the secondary fuel
filter. The fuel transfer pump has a fuel bypass valve
in order to allow the low pressure fuel system to be
primed.
Shutoff
The engine shuts off by interrupting the fuel supply.
The engine electronic control module (ECM) specifies
the amount of fuel. The quantity of the fuel that is
required by the ECM is set to zero.
Control
Illustration 27
Electronic control for the fuel system (typical example)
The ECM determines the quantity, timing and
pressure of the fuel in order to be injected into the
fuel injector.
The ECM uses input from the sensors on the engine.
These sensors include the speed/timing sensors and
the pressure sensors.
The ECM controls the fuel pressure by increasing
or decreasing the flow of fuel from the fuel injection
pump. The ECM controls the timing and the flow of
fuel by actuating the injector solenoid.
The amount of fuel is proportional to the duration of
the signal to the injector solenoid.
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