Electronic Accelerator Function - GF30.20-S-3015TRC

Engine 274 in model 447, 448 

Function requirements for the electronic accelerator, general points 

• Circuit 87M ON
• Engine runs

Electronic accelerator, general points 

The electronic accelerator (EA [EFP]) function is integrated into the ME-SFI [ME] control unit (N3/34) and controls the opening angle of the throttle valve dependent upon the driver input and the operating conditions.

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

• Accelerator pedal module (B37/4), accelerator pedal position over direct line
• Electronic Stability Program control unit (ESP) (N30/4), brake actuation via the chassis CAN (CAN E)
• Electronic Stability Program control unit (ESP), CC request via chassis CAN (with code MS1 (CC))
• Signaler detection and actuation module control unit (SAM) (N10/1), reverse travel signal from backup lamp switch (S16/2) via interior CAN (CAN B), electronic ignition lock control unit (EZS) (N73) and chassis CAN (with manual transmission)
• Fully integrated transmission control electric controller unit (VGS) (N15/11), gear range via the drive train CAN (CAN C) (with an automatic transmission)

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 accelerator pedal adaptation 

Function sequence for throttle valve control 

Depending on the accelerator pedal module, the ME-SFI [ME] control unit (B37/4) actuates the throttle valve actuator (M16/50) according to a characteristics map. To do this, the ME-SFI [ME] control unit actuates the actuator motor (M16/50m1) in the throttle valve actuator 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 potentiometer 1 (M16/50r1) and actual value potentiometer 2 (M16/50r2) report the current throttle valve position to the ME-SFI [ME] control unit.

Function sequence for throttle valve damping 

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

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

• Accelerator pedal module, accelerator pedal actuation (fast, slow)
• Crankshaft Hall sensor (B70/2), engine rpm
• Coolant temperature sensor (B11/21)
• Throttle valve actuator (M16/50), throttle valve position
• Electronic Stability Program control unit (ESP), wheel speed via the chassis CAN

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 accelerator pedal adaptation 

The ME-SFI [ME] control unit recognizes how the electronic 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 electronic accelerator pedal at first has to be pressed unusually far in order to obtain high acceleration.

The electronic accelerator supports further functions which are documented in separate function descriptions:

• Engine speed control
• Torque coordination
• Engine limp-home mode
• Cruise control (with CODE MS1 (Cruise control))

	Electrical function schematic for electronic accelerator	Engine 274 in model 448 except code XM0 (Facelift)	PE30.20-S-2050-97VDC
		Engine 274 in model 447 except code XM0 (Facelift)	PE30.20-S-2050-97TRC
	Overview of system components for gasoline injection and ignition system with direct injection	Engine 274 in model 447, 448 except code XM0 (Facelift)	GF07.70-S-9998TRC
		Engine 274 in model 447.6/7 with code XM0 (Facelift)	GF07.70-S-9998TRJ