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

ENGINE 113.986 

ENGINE 113.987 

ENGINE 113.988 

ENGINE 113.989 

Fig 1: ME-SFI Electronic Accelerator Function Diagram - Engine 113.988

The electronic accelerator function is integrated and controlled in the motor electronics control unit (N3/10) depending upon the driver input and the operating condition, the opening angle of the throttle valve.

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 (M16/6).

The opening angle of the throttle valve is changed by the actuator motor in the throttle valve actuator in accordance with the driver input and the operating conditions.

An actual value potentiometer in the throttle valve actuator reports the current position of the throttle valve to the motor electronics control unit.

A second actual value potentiometer in the throttle valve actuator and a second Hall sensor in the accelerator pedal sensor supply a reference value for the plausibility check.

Any detected errors are stored in the diagnostic trouble code memory and can be read out and deleted using STAR DIAGNOSIS.

Additional functions of the electronic accelerator pedal are: 

• Idle speed control
• Cruise control (CC)
• Torque reduction
• Emergency running
• Data transfer over CAN

Input signals for electronic accelerator pedal: 

• Accelerator pedal sensor
• Stop lamp switch (S9/1) from ESP and BAS control unit (ESP, PML and BAS) (N47-5)
• Cruise control switch (S40/4) from the steering column module (N80)
• Reduction data (torque) from ESP and BAS control unit (ESP, PML and BAS)
• Driving stages from the ETC [EGS] control unit (N15/3)

Throttle valve damping function 

The throttle valve damping function closes the throttle valve up to the idle speed range with a time delay if the accelerator pedal is suddenly released. In this way, the engine torque goes down slowly and the vehicle does not slow down with jerks.

The damping function of the throttle valve is integrated in the motor electronics control unit.

Following input signals are processed:

• Change in the speed of the accelerator pedal position.
• Engine speed
• Coolant temperature
• Throttle valve position
• Vehicle speed

Characteristic during reversing (drive position "R") 

A modified characteristic curve of the electronic accelerator should optimize the driving comfort and the safety while reversing.

The reversing action is indicated by the ETC [EGS] control unit to the motor electronics control unit via the CAN databus. The motor electronics control unit then utilizes a modified characteristic curve to regulate the throttle valve actuator.

Hereby, the throttle valve is opened slowly and the opening angle is limited to maximum 60 %.