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

Engine 178.9 in Model 190 

Function requirements for the electronic accelerator, general points 

• Circuit 87M (engine management ON)
• Engine runs

Electronic accelerator, general points 

The electronic accelerator function is integrated in the ME-SFI [ME] control unit (N3/10) and controls the engine torque depending on the driver command and the operating conditions.

The ME-SFI [ME] control unit regulates the engine torque, dependent on the following signals:

• Accelerator pedal sensor (B37), accelerator pedal position
• C1DISTRONIC electric controller unit () (for code 239 (DISTRONIC PLUS)), increase/reduce engine torque request to adjust the target distance via drive train CAN (CAN A89), powertrain control unit (N127) and chassis CAN 1 (CAN E1)
• Electronic Stability Program control unit (N30/4), brake actuation, CC requests and engine torque requests via chassis CAN 1, powertrain control unit and drive train CAN
• DKG control unit (N15/13), gear range and 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 drivability 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 position.

To do this the ME-SFI [ME] control unit actuates the following components:

• Left and right throttle valve actuator motors (M16/60m1, M16/61 m1) in the left and right throttle valve actuators (M16/60, M16/61) over a pulse width modulated signal
• Ignition coils (ignition coils for cylinder 1 + 2 coils to ignition coils for cylinder 7 + 8 (T4 to T4/3) to regulate the ignition timing
• Fuel injectors (Y76) for regulation of the lambda value over the fuel mass

The engine torque is then only determined by the accelerator pedal position if no limited or increased engine torque requests from other functions or control units (e.g. cruise control request) are active. The left and right actual value potentiometers 1 and 2 (M16/60r1, M16/602, M16/61r1, M16/61r2) signal the current throttle valve positions to the ME-SFI [ME] control unit.

Function sequence for drivability functions 

The drivability 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 drivetrain is prevented.

The drivability functions and the throttle change damping take place on the basis of the following signals:

• Accelerator pedal sensor, accelerator pedal actuation (fast, slow)
• Crankshaft Hall sensor (B70), engine rpm
• Coolant temperature sensor (B11/4), coolant temperature
• Oxygen sensor elements at left and right upstream of catalytic converter (G3/3b1, G3/4b1), oxygen and nitrogen content
• Oxygen sensor elements at left and right upstream of catalytic converter (G3/5b1, G3/6b1), oxygen and nitrogen content
• Electronic Stability Program control unit, vehicle speed via chassis CAN 1, powertrain control unit and drive train CAN

Function sequence for reverse travel 

If the DKG control unit sends the CAN signal "reverse travel" via drive train CAN, the engine torque is limited to approx. 50% by the ME-SFI [ME] control unit. This optimizes ride comfort and driving safety in reverse travel

Function sequence for adaptive accelerator pedal 

The ME-SFI [ME] control unit changes the response time 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).

	Electrical function schematic for electronic accelerator		PE30.20-P-2050-97HBA
	Overview of system components for gasoline injection and ignition system with direct injection		GF07.70-P-9998MNB