GF30.20-P-3015MI Electronic Accelerator Function

GF30.20-P-3015MI Electronic Accelerator Function
- ENGINE 272.9 (except 272.98) in MODEL 204.0 /2 as of model year 2009 /AEJ 08
- ENGINE 272.9 (except 272.98) in MODEL 204.9, 207.3 /4, 212.0 /2
- ENGINE 273.9 in MODEL 207.3 /4, 212.0 /2

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
- Front SAM control unit with fuse and relay module (N10/1), reverse travel signal from backup lamp switch (S16/2) via the chassis CAN (CAN E) (for a manual transmission)
- Electronic Stability Program control unit (N30/4) or Electronic Stability Program Premium control unit (N30/7) (for DISTRONIC PLUS), brake actuation via the chassis CAN
- Electronic Stability Program control unit, request for cruise control via the chassis CAN (for cruise control)
- Radar sensors control unit (N62/1), DISTRONIC request via the chassis CAN (for DISTRONIC PLUS)
- Clutch pedal switch (S40/3), clutch operation (for manual transmission)
- Fully integrated transmission control controller unit (Y3/8), gear range via the drive train CAN (CAN C) (for an automatic transmission)
- Fully integrated transmission control controller unit, reverse travel signal via the drive train CAN (for 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 actuation
- Function sequence for throttle valve damping
- Function sequence for reverse travel
- Function sequence for adaptive accelerator pedal

Function sequence for throttle valve actuation
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 [ME] 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.

Function sequence for throttle valve damping
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 positioner, throttle valve position
- Electronic Stability Program control unit, vehicle speed over the chassis 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.

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 when reversing.

Function sequence for adaptive accelerator pedal
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 in other documents are:
- Engine speed control
- Cruise control (if cruise control installed)
- DISTRONIC PLUS (for DISTRONIC PLUS)
- Torque coordination
- Engine limp-home mode