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

Engine 176.9, 177.9 in model 463 

as of model year 2019 

Function requirements for the electronic accelerator, general points 

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

The circuit relay 87M (K40/8kN) is switched on for circuit 15 ON.

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
• Brake actuation, CC requests and engine torque requests Electronic Stability Program control unit (N30/4), brake actuation, cruise control requests and engine torque requests via the chassis FlexRay (Flex E), powertrain control unit (N127) and drive CAN (CAN C1)
• Gear range and reverse travel signal The fully integrated transmission control unit (Y3/8n4) transmits the information via drive CAN to the ME-SFI [ME] control unit.
• Active Brake Assist controller unit (A108) (except code EM4 (Driver assistance package)) or Distance Pilot DISTRONIC controller unit (A108/1) (with code EM4 (Driver assistance package)), engine torque request (increase or decrease) via drive CAN, powertrain control unit, suspension FlexRay

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

Function sequence for electronic accelerator 

The function sequence for the electronic accelerator includes the following partial functions:

• 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 assembly parts:

• Left throttle valve actuator motor (M16/60m1) and right throttle valve actuator motor (M16/61m1) in left throttle valve actuator (M16/60) and right throttle valve actuator (M16/61) over a pulse width modulated signal (PWM signal)
• Ignition coil (ignition coil for cylinder 1 + 2 to ignition coil for cylinder 7 + 8 (T4 to T4/3)) for regulation of the ignition angle effectiveness over the firing point
• Cylinder 1 to 8 fuel injectors (Y76/1 to Y76/8) for regulation of the lambda value over the fuel quantity

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 actual value potentiometer 1 (M16/60r1), left actual value potentiometer 2 (M16/60r2), right actual value potentiometer 1 (M16/61r1) and right actual value potentiometer 2 (M16/61r2) transmit the current throttle flap position to the ME-SFI [ME] control unit.

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 drivetrain is prevented.

The driveability 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 speed
• Coolant temperature sensor (B11/4), coolant temperature
• Left lambda sensor element upstream of catalytic converter (G3/3b1) and right lambda sensor element upstream of catalytic converter (G3/4b1), nitrogen and oxygen concentration
• Left lambda sensor element downstream of catalytic converter (G3/5b1) and right lambda sensor element downstream of catalytic converter (G3/6b1), nitrogen and oxygen concentration
• The vehicle speed (calculated from the wheel speed signals) The Electronic Stability Program control unit sends the wheel speeds via the suspension FlexRay, powertrain control unit and drive CAN to the ME-SFI [ME] control unit.

Function sequence for reverse travel 

If the fully integrated transmission control unit sends the signal "reversing" via drive 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 slightly steeper accelerator pedal curve is used in order to improve the response time (reduction of free travel).

Further functions which support the electronic accelerator, are:

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

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