Operation
4002−1/A1
Winterthur Gas & Diesel Ltd.
5/ 15
3.2 Fuel Pressure Control
Main Bearing Oil
Fuel Pressure
Control Valve
Fuel Rail (one, or two part design related to number of cylinders)
Supply Unit
Drive
Injection
Fuel Booster
Pump (Plant)
System Bus
FCM−20
Cyl. 3
FCM−20
Cyl. 4
Fuel Shut-down
Pilot Valve
Fuel
Overpressure
Safety Valve
Fuel
Pumps
Fuel Pump
Actuators
FCM−20
Cyl. 5
FCM−20
Cyl. 6
Drawn for
6-cylinders to 8-cylinders
Fig. 3: Fuel Pressure Control System
3.2.1 Engine Start
At engine start,the fuel pump actuators are set to the start position (see Fig. 3).
3.2.2 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 WECS−9520 generates a control signal, which is related to the engine speed
and the fuel command.
D The signals from the FCM−20 control the three fuel pump actuators. Each
actuator controls the related fuel pump through the toothed rack.
D Two pressure transmitters measure the fuel pressure. This fuel pressure data is
transmitted back to the FCM−20 of cylinders 3 and 4.
3.2.3 Engine Shut-down
At engine shut-down, the fuel pump actuators are set to position zero and the the
safety system activates the fuel shut-down pilot valve.
3.2.4 Emergency Mode − One Actuator is Defective
If an actuator is defective, its control output stays in position or turns slowly to zero
supply.
The other actuators will continue to control the fuel pressure. At less than the medium
load, the fuel pressure control valve releases unwanted fuel.
2014
Engine Control System WECS-9520
To Next Page
Loading...
