Fuel Supply, Low-Pressure Side

Fuel Supply, Low-pressure Side

Electric fuel pump

The speed of the electric fuel pump is regulated by way of the specified frequency within the power limits of the fuel pump (with limitation of the phase current) and independently of the vehicle electrical system voltage (voltage compensation). The pump motor is a 3-phase synchronous motor without position feedback and without sensor.

Note on the control unit for electrical fuel pump on the Cayenne

On the Cayenne S Hybrid, the fuel pump delivery rate can be reduced to such an extent that the fuel pressure falls from approx. 83 psi (5.7 bar) to below 58 psi (4 bar), depending on the fuel requirement. The low pressure is detected by a pressure sensor for this. The fuel pressure sensor for detecting the low pressure is installed in the high-pressure pump supply line.

This control function differs from the V8 engines, which have a constant fuel low pressure of approx. 83 psi (5.7 bar).