Fuel Supply MSS60

Fuel Supply MSS60

Overview of functions
The pressure-controlled fuel supply with variable system pressure is handled by an electric fuel pump. The DME determines the requirement from the fuel pressure sensor signal and the operating condition of the engine. The DME sends the volume of fuel request as a CAN message across the Local Controller Area Network to the electric fuel pump.
The electric fuel pump converts the volume of fuel request into the activation of the fuel pump. The fuel pump is driven via an electrically commutated 3 phase electric motor. The value of the CAN message lies in the range between 0 and 100 % The electric fuel pump uses a characteristic curve to convert this value into a fuel pump speed and sets this speed at the fuel pump.
With full activation of the fuel pump, the fuel pressure is limited by the mechanical pressure regulator in the fuel tank to 6.2 bar.

For diagnostic functions of the DME, the electric fuel pump must send the following data via the Local Controller Area Network to the DME:
- Current fuel pump speed
- Input current of the fuel pump
- Status of the electric fuel pump
- Alive signal
- Software version of the electric fuel pump
- Voltage level at terminal 30 of the electric fuel pump. This is used to monitor the voltage supply of the electric fuel pump.

When terminal 15 is switched on, the electric fuel pump only starts up if the engine has been parked for a longer period.

Diagnosis instructions
The electric fuel pump is monitored by the electric fuel pump. If the electric fuel pump detects faults, the electric fuel pump reports the faults to the DME via the Local Controller Area Network. The faults are stored in the DME.
If faults are detected in the fuel supply, the fuel pump is run in emergency operation, i.e. the fuel pump is operated with 100 % activation.
The fuel system is airtight, i.e. the pressure is maintained after stopping the engine. After one hour, at least 1 bar must be maintained.