Fuel Supply System: Notes

A separate control unit is used for the electric fuel pump (EKP-SG). The EKP control signals from the MSS60 are produced via a dedicated CAN bus (LoCAN) (M5: PWM signal). The EKP control unit is made ready for operation by the MSS60 via the input terminal 87. The load current is controlled via a relay at the terminal 30g by CAS3.

In the event of a crash that reaches the relevant threshold value, the MRS5 requests an interrupt to the fuel supply via the K-CAN connection to CAS3.

There is now only one fuel pump (the M5 has two). This has a three-phase motor, which ensures sufficient torque across the whole pump speed range. The pump speed is used to provide the required fuel pressure of 3-6 bar, depending on the engine operating state.

A fuel pressure sensor sends its signal to the MSS60. The fuel pressure sensor is located behind the inner fenderwell.

If the pressure sensor fails or there is a fault in the CAN bus and in the engine emergency program, the fuel pump is operated at full speed. In this process, the pressure is limited to 6 bar by the mechanical pressure sensor.

The signals from both tank fill level sensors are sent to the junction box and are forwarded to the instrument cluster via the K-CAN, where they are evaluated and displayed.