Electronic accelerator function - GF30.20-P-3015MMO

ENGINE 276.9 in MODEL 212.095 up to model year 2014 

Function requirements for the electronic accelerator, general points 

• Circuit 87M (engine timing ON)
• Engine running

The function requirements "internal combustion engine running" includes all function sequences of the fuel low pressure and high-pressure circuit, as described in the function "fuel supply".

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 according to the following sensors and signals:

• Accelerator pedal sensor (B37), accelerator pedal position
• Regenerative braking system control unit (N30/6), brake actuation via chassis CAN (CAN E)
• Regenerative braking system control unit, CC request via chassis CAN
• Video and radar sensor system control unit (N62/2) (for code (233) DISTRONIC PLUS)

  for code (237) Active Blind Spot Assist

  For code (238) Active Lane Keeping Assist), engine torque request via chassis CAN

• Fully integrated transmission control unit (Y3/8n4), gear range over drive train CAN (CAN C)
• Fully integrated transmission control unit, reverse travel signal via the 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 engine torque specification 
• Function sequence for driveability functions 
• Function sequence for reverse travel 
• Function sequence for adaptive accelerator pedal 

Function sequence for engine torque specification 

The ME-SFI [ME] control unit actuates the engine torque dependent on a characteristic map, dependent on the accelerator pedal sensor. To do this the ME-SFI [ME] control unit actuates the following components:

• Actuator motor (M16/6m1) in the throttle valve actuator (M16/6) by means of a pulse width modulated signal (PWM signal)
• Ignition coils (T1) for regulation of the ignition angle efficiency via ignition timing
• Fuel injectors (Y76) for regulation of the lambda value via fuel quantity

The engine torque is then only determined by the accelerator pedal position if no limited or increased torque requests from other functions or control units (e.g. cruise control request) are active. The actual value potentiometers 1 and 2 (M16/6r1, M16/6r2) report the current throttle valve position to the ME-SFI [ME] control unit.

The position feedback of the throttle valve actuator takes place by means of a contact-less angular sensor.

Function sequence for driveability functions 

The driveability functions and throttle change damping have the task of limiting the change of engine torque as a result of a rapid movement of the accelerator pedal. The limitation serves to improve the ride comfort since jolting in the drive train is prevented.

The driveability functions and the throttle change damping takes place on the basis of the following sensors and signals:

• Accelerator pedal sensor, accelerator pedal actuation (fast, slow)
• Crankshaft Hall sensor (B70), engine speed
• Coolant temperature sensor (B11/4)
• Left and right oxygen sensor elements upstream of catalytic converter (G3/3b1, G3/4b1)
• LH and RH oxygen sensor elements downstream of catalytic converter (G3/5b1, G3/6b1)
• Regenerative braking system control unit, wheel speed via the chassis CAN

Function sequence for reverse travel 

If the fully integrated transmission control unit transmits the CAN signal "reverse travel" via the drive train CAN, the engine torque is limited to about 50% by the ME-SFI [ME] control unit. This optimizes ride comfort and driving safety when reversing.

Function sequence for adaptive accelerator pedal 

The ME-SFI [ME] control unit changes the actuation characteristics of the accelerator pedal depending on the vehicle speed calculated from the wheel speed. At higher vehicle speeds a somewhat steeper accelerator pedal curve is used in order to improve the response time (reduction of the free travel).

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

• RPM control
• Torque coordination
• Engine limp-home mode