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

ENGINE 113.967 in MODEL 219

ENGINE 113.964 in MODEL 164.1

ENGINE 113.971 in MODEL 251

Fig 1: Function - ME-SFI Electronic Accelerator

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

The function of the electronic accelerator (EA) N3/10 the ME-SFI control unit determines the opening angle of the air recirculation flap 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 (B37) located on the accelerator pedal mechanically.

The Hall sensor in the accelerator pedal sensor sends an appropriate voltage signal to the motor electronics control unit. The motor electronics control unit 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 1 in the throttle valve actuator reports the current position of the throttle valve to the motor electronics control unit.

The second potentiometer in the throttle valve actuator and the second signal from the pedal value sensor supply a reference value for a plausibility check. Furthermore, a switchover to the additional sensor takes place if the first signal fails (emergency mode).

Further functions are:

Idle speed control
Cruise control mode
Variable speed limiter, except
Requests of momentary interface, such as:
- Reducing or increasing the engine torque for ESP operation
- Load limitation when coolant temperature is too high
- Reducing engine torque during gear-shift operation
- Reduces engine torque at maximum speed
Emergency running
Fault storage
Data exchanger via CAN

The input signals for the EA function are:

Accelerator pedal sensor
Stop lamp switch (CAN message "Driver applies brakes")
Hot film mass air flow sensor
CC [TPM] switch
Requirement of torque interface
Information selector lever position P/N and drive position engaged from transmission control unit.

When braking is detected, the idle speed is always controlled.

Reversing

If reversing is detected by the ME control unit through a CAN message from the transmission control unit, the throttle valve is opened more slowly. The maximum opening angle of the throttle valve is limited to around 50 %.

This function has the task of optimization of ride comfort and safety when reversing.

Adaptive accelerator pedal

The ME control unit recognizes how the accelerator pedal is being actuated and switches between characteristic curves. Eighty percent of the engine load is released for a pedal travel of about 50 % for a sporty driver and about 40 % for a quiet driver. There no further difference to be felt after about 90 % of the full pedal travel.

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

	Motor electronics control unit component description		GF07.61-P-6000BK
	Accelerator pedal sensor component description		GF30.20-P-2010BK
	Component description of throttle valve actuator		GF30.20-P-2020BK
	Component description of hot film MAF sensor		GF07.07-P-6000BK