Electronic Accelerator Function - GF30.20-P-3015MRA

Engine 274.9 in model 205 (except 205.047/053/054/147/247/253) 

Engine 274.9 in model 253 (except 253.354/954) 

Function requirements for the electronic accelerator, general points 

• Circuit 87M (Engine management ON)
• Engine running

Electronic accelerator, general points 

The electronic accelerator (EA [EFP]) function is integrated into the ME-SFI [ME] control unit (N3/10) and controls the opening angle of the throttle valve depending upon the driver input and the operating conditions. The ME-SFI [ME] control unit regulates the throttle valve position, dependent on the following signals:

• Accelerator pedal sensor (B37), accelerator pedal position
• Clutch pedal sensor (B53/1), clutch operation (for manual transmission)
• Manual transmission main shifter shaft position sensor (B79/3) (for manual transmission), reverse gear signal engaged
• Electronic Stability Program control unit (N30/4), brake actuation and cruise control requests via chassis FlexRay (Flex E), powertrain control unit (N127) and drive train CAN (CAN C1)
• Radar sensors control unit (N62/1) (for code 23P (Driver Assist Package)), engine torque request via the chassis FlexRay, powertrain control unit and drive train CAN
• Fully integrated transmission control unit (Y3/8n4) (for A/T), gear range and reverse travel signal over drive train CAN

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

Function sequence for electronic accelerator 

The function sequence is described in the following steps:

• Function sequence for throttle valve control 
• Function sequence for throttle valve damping 
• Function sequence for reverse travel 
• Function sequence for adaptive accelerator pedal 

Function sequence for throttle valve control 

Depending on the accelerator pedal sensor, the ME-SFI [ME] control unit actuates the throttle valve actuator (M16/6) according to a characteristics map. To do this, the ME-SFI [ME] control unit actuates the throttle valve actuator motor (M16/6m1) by means of a pulse width modulated signal (PWM signal). 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 potentiometers 1 and 2 (M16/6r1, M16/6r2) report the current throttle valve position to the ME-SFI [ME] control unit.

Function sequence for throttle valve damping 

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

• Accelerator pedal sensor, accelerator pedal actuation (fast, slow)
• Coolant temperature sensor (B11/4)
• Crankshaft Hall sensor (B70), engine rpm
• Throttle valve actuator, throttle valve position
• Electronic Stability Program control unit, wheel speed via the chassis CAN

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

Function sequence for reverse travel 

If the ME-SFI [ME] control unit receives the reverse travel CAN signal, 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 in reverse travel.

Function sequence for adaptive accelerator pedal 

The ME-SFI [ME] control unit recognizes how the accelerator pedal is being actuated and switches between two 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 relaxed driver. There is no further difference felt above a pedal travel of about 90%.

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.

	Electrical function schematic for electronic accelerator		PE30.20-P-2050-97FBA
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