Electronic fuel pump
The electric fuel pump is an in-tank unit; its function is to supply fuel to the engine.
In the "electronic control of the fuel pump" system, the electronic fuel pump is activated in line with requirements. The DME employs driver demand and instantaneous engine operating conditions to calculate the quantity of fuel required at any specific juncture. The required fuel quantity is transmitted to the EKPS electronic fuel pump control unit in the form of a message on the CAN bus.
The EKPS electronic fuel-pump control unit translates this message into a PWM output voltage. This process is supported by characteristic curves for fuel requirement stored in the EKPS electronic fuel-pump control system. The characteristic curves are coded for the specific motor and model.
The EKPS electronic fuel pump control unit uses a pulse width-modulated output voltage (PWM signal) to regulate the speed of the electric fuel pump, thereby ensuring that the fuel pump delivers precisely the amount of fuel required.
The electric fuel pump delivers fuel from the tank to the high-pressure pump through the supply line at a pressure of roughly 5 bar. This primary pressure is monitored by the fuel-pressure sensor. The electric fuel pump's delivery rate is controlled by demand.
| Index | Explanation |
|---|---|
| 1 | Service cap (with connections for components inside the fuel tank) |
| 2 | Plug connection for the electronic fuel pump |
| 3 | Plug connection for the fuel level sensors |
| 4 | Float on lever arm fuel level sensor 2 |
| 5 | Electronic fuel pump |
The fuel-pump relay activates the electric fuel pump when Terminal 15 is switched on.