ME-SFI electronic accelerator, function - GF30.20-P-3012MIG

ENGINES 272.945 in MODEL 251.054/154 as of model year 2009/CY 08

ENGINES 272.967 in MODEL 164.186 as of model year 2009/CY 08 model refinement package

ENGINES 272.967 in MODEL 251.056/065/156/165 as of model year 2009/CY 08

ENGINES 273.923 in MODEL 164.871 as of model year 2009/CY 08

ENGINES 273.963 in MODEL 164.172 as of model year 2009/CY 08 model refinement package

ENGINES 273.963 in MODEL 164.886, 251.072/172 as of model year 2009/CY 08

Function requirements for the electronic accelerator, general points

Circuit 87M ON (engine control ON)
Engine running

Electronic accelerator, general points

The electronic accelerator function (EFP) is integrated in the ME-SFI [ME] control unit (N3/10), and controls the opening angle of the throttle valve according to driver requests and 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
Electric controller unit (VGS) (Y3/8), gear range over the engine compartment CAN (CAN C)
Electric controller unit (VGS), reverse travel via engine compartment CAN
ESP control unit (N47-5), brake actuation over the engine compartment CAN
ESP control unit, cruise control request over the engine compartment CAN
ESP control unit, Distronic request over the engine compartment CAN (if Distronic installed)

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

Electronic accelerator function sequence

The function sequence is described in the following steps:

Throttle valve actuation function sequence
Throttle valve damping function sequence
Reverse travel function sequence
Adaptive accelerator pedal function sequence

Throttle valve actuation function sequence

Depending on the accelerator pedal sensor, the ME-SFI [ME] control unit actuates the throttle valve actuator (M16/6) according to a performance map. To do this, the ME-SFI control unit operates the actuator motor (M16/6m1) in the throttle valve actuator with 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.

Throttle valve damping function sequence

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

Accelerator pedal sensor, accelerator pedal actuation (fast, slow)
Crankshaft Hall sensor (B70), engine speed
Coolant temperature sensor (B11/4)
Throttle valve actuator, throttle valve position
ESP control unit, vehicle speed via the engine compartment CAN

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

Reverse travel function sequence

If the ETC electric controller unit sends the "reverse travel" CAN signal over the engine compartment CAN, the ME-SFI control unit opens the throttle valves slowly and limits the maximum opening angle to about 50 %. This optimizes ride comfort and driving safety when reversing.

Adaptive accelerator pedal function sequence

The ME-SFI [ME] control unit recognizes how the accelerator pedal is being actuated and switches between 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 quiet 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.

Further functions which support the electronic accelerator and which are described :

Idle speed control
Cruise control
DISTRONIC (if DISTRONIC installed)
Engine torque request
Emergency electronic accelerator pedal

Electrical function schematic for electronic accelerator	Model 164		PE30.20-P-2050-97MAA
Electrical function schematic for electronic accelerator	Model 251		PE30.20-P-2050-97RAA
ME-SFI [ME] control unit, component description	N3/10	Engine 272	GF07.61-P-6000MIG
ME-SFI [ME] control unit, component description	N3/10	Engine 273	GF07.61-P-6000MLG