The fuel metering valve regulates the quantity of fuel fed to the high-pressure chamber of the high-pressure pump as a function of fuel pressure in the fuel rail in accordance with the fuel requirements.
As a result, the quantity of fuel that flows back to the fuel tank is kept to a minimum.
1 Transfer pressure
2 To the high-pressure chamber of the high-pressure pump
NOTE: The fuel metering valve operates together with the fuel pressure sensor (on the fuel rail) in a closed control loop.
The fuel metering valve is controlled by PWM signals from the IDM. The type of pulse width modulation is a function of:
โข Driver’s requirements
โข Fuel pressure requirement
โข Engine speed
The fuel metering valve is fully opened in its de-energized state.
Effects of faults
In the event of a fault, the injected fuel quantity is set to 0 and the engine cuts out or cannot be started.
Malfunctions in the fuel metering valve are detected by continually comparing the fuel pressure request (calculated by the system) and the actual fuel pressure (measured in the fuel rail). If there is a discrepancy of more than ยฑ 50 bar, the injected fuel quantity is set to 0 and the engine cuts out or cannot be started (see also section on “Fuel pressure outside range”).
Diagnosis
The monitoring system checks:
โ the sensor for short circuit to ground/battery and open control loop.
โ Note: The fuel metering valve is part of the fuel pressure regulating system (see also the section on “Fuel pressure control”).