The flow regulating valve is an electrically controlled valve that is mounted on the high pressure pump. When volumetric flow regulation is active, the DDE controls the flow regulating valve by means of a variable pulse duty factor in order to set the rail pressure to the level calculated by the DDE.
The flow regulating valve controls the flow of fuel into the high pressure pump from the low-pressure side, thereby controlling fuel-rail pressure as required. The less fuel the flow regulating valve allows to flow into the high pressure side, the less the radial cylinders of the high-pressure pump are filled. Consequently, the fuel-rail pressure is correspondingly lower.
Pulse duty factor, control signal current, rail pressure and volumetric flow through the valve are related to one another as follows:
Pulse duty factor |
Control signal current |
Pressure build-up |
Volumetric flow into high-pressure side |
|---|---|---|---|
High |
High |
Low |
Low |
Low |
Low |
High |
High |
If a fault is detected in the control of the flow regulating valve, the following faults may be stored:
Consequence: