GF30.20-P-3012MOS ME-SFI Electronic Accelerator, Function

GF30.20-P-3012MOS ME-SFI Electronic Accelerator, Function
- ENGINE 275.953 in MODEL 216.376, 221.176 as of Model Year 09 /AEJ 08
- ENGINE 275.982 in MODEL 216.379, 221.179 as of Model Year 09 /AEJ 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 control unit (N3/10), and controls the opening angle of the throttle valve according to driver requests and operating conditions.

The ME-SFI control unit regulates the throttle valve position according to the following sensors and signals:
- Accelerator pedal sensor (B37), accelerator pedal position
- ETC control unit (N15/3), gear range over the drive train CAN (CAN C)
- ETC control unit (N15/3), reverse travel over the drive train CAN
- ESP control unit (N47-5), brake actuation over the chassis CAN (CAN E)
- ESP control unit, cruise control request over the chassis CAN
- Radar sensors control unit (SGR) (N62/1), Distronic request over the chassis CAN (for Distronic PLUS)

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

Throttle valve actuation function sequence
Depending on the accelerator pedal sensor, the ME-SFI control unit actuates the throttle valve actuator (M16/6) according to a performance map. To do this, the ME-SFI control unit actuates 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 control unit controls the throttle valve damping according to the following sensors and signals:
- Accelerator pedal sensor, accelerator pedal actuation (fast, slow)
- Coolant temperature sensor (B11/4)
- Crankshaft position sensor (L5), motor speed
- Throttle valve actuator, throttle valve position
- ESP control unit, vehicle speed over the chassis CAN

The purpose of throttle valve damping is to delay the closing of the throttle valve down to idle speed range if the accelerator pedal is suddenly released. In this way, the engine torque goes down 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, 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.

Further functions which support the electronic accelerator and which are described in other documents are:
- Idle speed control
- Cruise control
- Distronic PLUS (if Distronic PLUS installed)
- Engine torque request
- Emergency electronic accelerator pedal