ME-SFI electronic accelerator, function - GF30.20-P-3012M

ENGINE 275.950 in MODEL 215, 220

ENGINE 275.951 in MODEL 230 up to Model Year 8

ENGINE 275.953 in MODEL 216, 221 up to Model Year 8

ENGINE 275.954 in MODEL 230 up to Model Year 8

ENGINE 275.980 in MODEL 215, 220

ENGINE 275.981 in MODEL 230 up to Model Year 8

ENGINE 275.982 in MODEL 216, 221 up to Model Year 8

ENGINE 285.950 in MODEL 240

ENGINE 285.980 in MODEL 240

Fig 1: ME-SFI Electronic Accelerator Function Diagram

Courtesy of MERCEDES-BENZ USA

The function of the electronic accelerator (EA) in the ME-SFI [ME] control unit determines the opening angle of the throttle valve in line with the accelerator pedal input.

The position of the accelerator pedal and the speed at which the position of the accelerator pedal changes are transmitted to the sensor located on the accelerator pedal mechanically

The Hall sensor in the accelerator pedal sensor sends an appropriate voltage signal to the ME-SFI [ME] control unit. This analyzes the voltage signal and depending upon the performance map, activates the throttle valve actuator motor.

The opening angle of the throttle valve will only be determined by the accelerator pedal specification when no limiting functions are active.

The actual value potentiometer (sliding contact 1) (M16/6r3) in the throttle valve actuator reports the current position of the throttle valve to the ME-SFI [ME] control unit.

The actual value potentiometer (sliding contact 1) (M16/6r4) in the throttle valve actuator and the second signal from the pedal value sensor supply a reference value for a plausibility check.

Furthermore it is switched over to the additional sensors, if the first signal fails (emergency mode).

Further functions are:

Idle speed control
Tempomat (cruise control)/Distronic
Variable Speed Limiter
Requests of momentary interface, such as:
- Reducing or increasing the engine torque for ESP operation
- Load limitation at too high coolant temperature
- Load limitation at too high boost pressure
- Reducing engine torque during gearshift operation
- Reducing engine torque at maximum speed
Emergency running
Fault storage
Data transfer via CAN

The input signals for the EA function are:

Accelerator pedal sensor
Brake light signal (CAN message "Driver brakes") from ESP control unit
Pressure sensor downstream of throttle valve actuator (B28/7)
Cruise control/Distronic requests
Torque request from ESP control unit
Driving stages from ETC control unit

If the brake pedal is operated, this always means idle speed input.

Adaptive accelerator pedal

The ME-SFI [ME] control unit recognizes how the accelerator pedal is being actuated and switches between characteristic curves. After a pedal travel of about 50% about 80% of the engine load is released for a sporty driver and about 10% for a quiet driver. There is no further difference felt above a pedal travel of about 90 %.

If, for example, the characteristic curve for a quiet driver is active after a long drive on the freeway then the accelerator pedal must be pressed down unusually hard to obtain a higher acceleration level.

	ME-SFI [ME] control unit, location/task/design/function		GF07.61-P-5000M
	Accelerator pedal sensor, location/task/design/function		GF30.20-P-4010M
	Throttle valve actuator, location/task/design/function		GF30.22-P-4101M
	Pressure sensor downstream of throttle valve actuator, location/task/function		GF07.04-P-5049M
	Crankshaft position sensor, location/task/design/function		GF07.04-P-4116M