Fuel Flow

Fuel flow






The variable speed fuel pump is contained in a fuel reservoir in the RH compartment Fuel is pumped from the reservoir through an external crossover pipe to the LH compartment where it flows via a T junction to the parallel pressure relief valve and then out to the engine fuel rail. The reservoir fuel level is maintained by fuel supplied by jet pumps in the LH and RH compartments. The jet pumps in both compartments are charged by the fuel pump.


Fuel from the LH compartment is pumped through an external crossover pipe to the reservoir. The RH compartment jet pump is located in the base of the reservoir.


The parallel pressure relief valve assembly contains two spring loaded valves, which operate in opposite directions, a fuel rail feed valve, which opens at approximately 0.014 Bar ( 0.2 psi ) during normal operation and a second valve, which opens at approximately 3.11-4.83 Bar ( 45-70 psi ) to relieve excessive rail pressure.


The main functions of the parallel pressure relief valve assembly are:

- To help engine starting by retaining fuel in the supply lines and rail.
- To limit rail pressure due to temporary vapor increase during hot soak conditions (temperature and thus pressure drop after approximately 20 minutes.)
- To limit rail pressure caused by sudden load changes such as a full to closed throttle transition. To prevent siphoning from the tank in the even of the fuel line being severed with the pump inactive.