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

ENGINE 273 in MODEL 463.202/222/236/237 up to 31.5.12 as of Model Year 2009/YoM 08 

Fig 1: Identifying ME-SFI Electronic Accelerator Function Diagram
G07887903Courtesy of MERCEDES-BENZ USA

Function requirements for the electronic accelerator for the ME-SFI gasoline injection and ignition system (engine electronics) (ME), general points 

ME-SFI electronic accelerator, general points 

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

The ME-SFI [ME] control unit regulates the throttle valve position according to the following sensors and signals:

The requirements of the engine torque requirement function are also taken into account.

ME-SFI electronic accelerator, function sequence 

The function sequence consists of the following subfunctions:

Throttle valve actuation function sequence 

Depending on the accelerator pedal sensor, the ME-SFI [ME] control unit actuates the throttle valve actuator according to a performance map. To do this, the ME-SFI [ME] control unit operates the actuator motor (M16/6m1) in the throttle valve actuator by means of a signal (pulse width modulation (PWM)). Provided there are no limiting functions active (for example, cruise control request), the opening angle of the throttle valve is determined by the accelerator pedal position alone.

The actual value potentiometer for the throttle valve (M16/6r1) and actual value potentiometer for the drive (M16/6r2) report the current throttle flap position to the ME-SFI [ME] control unit.

Throttle valve damping function sequence 

The ME-SFI [ME] control unit controls the throttle valve damping according to the following sensors and signals:

The purpose of throttle valve damping is to delay the closing of the throttle valve down to idle speed range if the accelerator pedal is suddenly released. In this way, the engine torque reduces slowly and the vehicle does not slow down with jerks.

Reverse travel function sequence 

If the ETC electric controller unit sends the "reverse travel" CAN signal via the drive train CAN, the ME-SFI [ME] control unit opens the throttle valves slowly and limits the maximum opening angle to about 50%. This optimizes ride comfort and driving safety when reversing.

Adaptive accelerator pedal function sequence 

The ME-SFI [ME] control unit recognizes how the accelerator pedal is being actuated and switches between characteristic curves. After a 50% pedal travel, about 80% of the engine load is released for a sporty driver and 40% of the engine load is released for a quiet driver. There is no further difference felt above a pedal travel of about 90%.

IMPORTANT If the calm driver characteristic is active (for example, after a long journey on the freeway), the accelerator pedal at first has to be pressed unusually far in order to obtain high acceleration.

IMPORTANT Further functions which support the electronic accelerator and which are described in other documents are:

  Component description for ME-SFI [ME] control unit N3/10 GF07.61-P-6000G
  Component description for ESP control unit N30/4 GF42.45-P-5118G
  Component description for fully integrated transmission control unit Y3/8n4 GF27.60-P-5165GGA
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