Electronic Accelerator Function - GF30.20-P-3015MMM
ENGINE 276.8 in MODEL 166.063 as of model year 2016
Function requirements for the electronic accelerator, general points
- Circuit 87M (engine management ON)
- Engine runs
Electronic accelerator, general points
The electronic accelerator function is integrated in the ME-SFI [ME] control unit (N3/10) and controls the drivetrain torque depending on the driver command and the operating conditions.
Drivetrain torque
On vehicles with internal combustion engine without hybrid drive, the drivetrain torque is the torque from the internal combustion engine which is transmitted to the drivetrain via the crankshaft.
On vehicles with hybrid drive, the torques from the internal combustion engine and the electrical machine (A79/1) are added together, resulting in a drivetrain torque.
The ME-SFI [ME] control unit regulates the drivetrain torque, dependent on the following signals:
- Accelerator pedal sensor (B37), accelerator pedal position
- Brake actuation, cruise control request and specified torque request from the Electronic Stability Program control unit (N30/4) via the engine CAN (CAN C1), powertrain control unit (N127) and chassis CAN 1 (CAN E1)
- Specified torque request (increase or reduction) from radar sensors control unit (N62/1) (with CODE 23P (Driving assistance package)) via engine CAN, powertrain control unit, chassis CAN 1, chassis gateway control unit (N93/7) and chassis FlexRay (Flex E)
- Gear range and reverse travel signal from fully integrated transmission control unit (Y3/8n4) via drive train CAN
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 drivetrain torque specification
- Function sequence for driveability functions
- Function sequence for reverse travel
- Function sequence for adaptive accelerator pedal
Function sequence for drivetrain torque specification
The ME-SFI [ME] control unit controls the drivetrain torque based on a characteristics map depending on the accelerator pedal sensor. To do so, the ME-SFI [ME] control unit actuates the following components in driving operation with internal combustion engine or hybrid driving mode:
- Actuator motor (M16/6m1) of throttle valve via a pulse width modulated signal
- Ignition coils (T1) for regulation of the ignition angle efficiency (results from shifting of the actual ignition angle from the optimal ignition angle) via the ignition timing.
- Fuel injectors (Y76) to regulate the lambda value over the fuel quantity
If traction on vehicles with hybrid drive is not provided exclusively by the internal combustion engine, e.g. in the case of hybrid driving mode or electric mode (cruising mode, maneuvering), the ME-SFI [ME] control unit sends a request for a specified torque of the electrical machine to the power electronics control unit (N129/1).
Further information about the various driving conditions on vehicles with hybrid drive is given in the following document:
- Vehicle conditions of the HYBRID system function
The drivetrain torque is only determined exclusively from the accelerator pedal position if no limited or increased torque requests from other functions or control units (e.g. cruise control request) are active. 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 driveability functions
The driveability functions and throttle change damping have the task of limiting the change in drivetrain torque caused by rapid movement of the accelerator pedal. The limitation serves to improve the ride comfort since jolting in the drivetrain is prevented.
On vehicles with hybrid drive, dynamic torque interventions are not implemented exclusively using the torque reserve of the internal combustion engine.
The ME-SFI [ME] control unit initially implements torque interventions in the current drivetrain torque via the electrical machine. To do this it requests the motor-generated torque from the electrical machine from the power electronics control unit via the CAN in order to increase the torque.
Reducing torque interventions are realized through requests for a generated torque.
The power electronics control unit implements these requests and reports back the torque generated in this manner via the CAN to the ME-SFI [ME] control unit. If the torque interventions of the electrical machine are not sufficient then the torque from the internal combustion engine is additionally reduced or increased (torque reserve).
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)
- Coolant temperature sensor (B11/4), coolant temperature
- Pressure sensor downstream of throttle valve (B28/7), engine load
- Crankshaft Hall sensor (B70), engine rpm
- Sensor elements of left and right oxygen sensor, upstream of catalytic converter (G3/3b1, G3/4b1)
- Sensor elements of left and right oxygen sensor, downstream of catalytic converter (G3/5b1, G3/6b1)
- Electronic Stability Program control unit, wheel speed via chassis CAN 1
Function sequence for reverse travel
If the fully integrated transmission control unit sends the CAN signal "reverse travel" via drive train CAN, the vehicle speed is limited to 60 km/h by the ME-SFI [ME] control unit. This optimizes driving safety during 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 somewhat steeper accelerator pedal curve is used in order to improve the response time (reduction of the free travel).
Further functions which support the electronic accelerator and which are described in other documents:
- Rpm control
- Torque coordination
- Engine limp-home mode
| Electrical function schematic for electronic accelerator | PE30.20-P-2050-97NBH | ||
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