Operation4002−1/A1
Winterthur Gas & Diesel Ltd.
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3.7 Diesel Fuel Pressure Control
3.7.1 Engine Start
At engine start, the fuel pump actuators are set to the start position (see Fig. 8).
3.7.2 Engine Operation
The fuel pressure is related to the engine load. The control loop for the fuel rail
pressure is given as follows:
D The engine control system (ECS) activates a control signal, which is related to
the engine speed or estimated power.
D The signals from the CCM-20 control the fuel pump actuators. Each actuator
controls the related fuel pump through the toothed rack.
D CCM-20 Cyl. 1 controls the fuel quantity of fuel pump No.1. The ECS sends
a signal to the control valve CV7231C.
D CCM-20 Cyl. 2 controls the fuel quantity of fuel pump No.2. The ECS sends
a signal to the control valve CV7232C.
D CCM-20 Cyl. 3 controls the fuel quantity of fuel pump No.3. The ECS sends
a signal to the control valve CV7233C.
D Two pressure transmitters PT3461C and PT 3462C measure the fuel pressure.
This fuel pressure data is transmitted back to the CCM-20 Cyl. 1 and
CCM-20 Cyl. 2.
3.7.3 Engine Shut-down
If the fuel rail pressure must be quickly released, the fuel pump actuators are set to
the position zero. The engine will open the pressure control valve (PCV) to release
the pressure in the fuel rail (see Fig. 8).
The PCV also operates as a safety valve. For more data, see 5562−1 Pressure
Control Valve.
3.7.4 Emergency Mode
If the controlling CCM-20 or fuel pump becomes defective, the remaining fuel pumps
keep the fuel rail pressurized and the engine can continue to operate.
3.7.5 Monitored Items
The fuel rail pressure is monitored. If the pressure is out of the tolerance, a failure
indication shows.
The sensors are monitored. If the sensors are out of range, a failure indication shows.
Engine Control System
2015-12
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