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

ENGINE 156.980 in MODEL 164, 251

ENGINE 156.982 in MODEL 209

ENGINE 156.983 in MODEL 211, 219

ENGINE 156.984 in MODEL 216, 221

Fig 1: ME-SFI Electronic Accelerator Function Diagram

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

The electronic accelerator function (EFP) is integrated in the ME-SFI [ME] control unit and controls the opening angle of the throttle valves depending on driver input and the operating condition.

Input signals for the electronic accelerator pedal:

Accelerator pedal position (from accelerator pedal sensor)
Air mass (from hot film mass air flow sensor)
Brake actuation (via the ESP control unit)
Cruise control operation (from ESP control unit)
Request from torque interface (e.g. from ESP control unit and electric controller unit (VGS))
Selector lever position (from electronic selector lever module control unit for model 209, 211, 219 or from intelligent servo module for DIRECT SELECT for model 164, 216, 221, 251)
Drive positions (from electric controller unit (VGS))
If the brake pedal is operated, this always means idle speed input.

The position of the accelerator pedal and 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 motor electronics control unit. The ME-SFI [ME] control unit analyzes the voltage signal and actuates the throttle valve actuators in parallel according to the performance map.

The opening angles of throttle valves are altered by the actuator motors in the actuators according to actuation by the ME-SFI [ME] control unit.

The opening angles of throttle valves are only determined by the accelerator pedal request if no limiting function are active (e.g. idle request or a torque reduction).

The actual value potentiometer in actuators report the current throttle valves to the ME-SFI [ME] control unit.

The second potentiometer in the throttle valve actuators and the second Hall sensor in the accelerator pedal sensor deliver reference values for plausibility checking of input signals to the ME-SFI [ME] control unit.

Ignition "On"

Upon switching on the ignition, throttle valve actuators are actuated by the ME-SFI [ME] control unit and take on a throttle valve position dependent on the coolant temperature.

Reverse travel

If reverse travel (selector lever position "R") is recognized by the ME-SFI [ME] control unit, the throttle valve are opened more slowly and the maximum opening angle of the throttle valves is limited to about 50%.

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

Adaptive accelerator pedal

The ME-SFI [ME] control unit recognizes how rapidly the accelerator pedal is being actuated and switches between characteristic curves.

After approx. 50% pedal travel by a sporty driver, around 80% of engine load is released and by a smooth driver, around 40%. From a pedal travel of about 90% the full load request takes place for both characteristic and there no difference noticeable anymore.

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.

Additional functions of the electronic accelerator pedal:

Idle speed control
Cruise control (CC [TPM])
Variable/Permanent Speed Limiter
Torque interface
Emergency running
Fault storage
Data transfer over CAN

Component description for crankshaft Hall sensor	B70	GF07.04-P-6220AMG
Component description for the hot film mass air flow sensor	B2/6, B2/7	GF07.07-P-6000AMG
Component description for the ME-SFI [ME] control unit	N3/10	GF07.61-P-6000AMG
Component description for the accelerator pedal sensor	B37	GF30.20-P-2010AMG
Component description for the throttle valve actuator	M16/3, M16/4	GF30.20-P-2020AMG