ASR drive torque control circuit, function

Acceleration slip regulation (ASR)

To achieve optimum traction if the drive torque is too high (wheel spinning) acceleration slip regulation is required. The acceleration slip reduction is controlled by an exchange of data via the CAN data bus between the installed ASR (N47-1) or ESP (N47-5) traction system and the respective injection and ignition system control module. With gasoline engines these control modules are: EAN4/1), LH-SFI (N3/1, N3/2, N3/3), HFM-SFI (N3/4) or ME-SFI (N3/10, N3/11, N3/12) and with diesel engines these control modules are: IFI (N3/7), DFI (N3/8) or CDI (N3/9).

 4-cylinder gasoline engine with supercharger, 6, 8, and
12-cylinder gasoline engine:
the EA (N4/1) or ME-SFI control module (N3/10, N3/11, N3/12) reduces the position of the throttle valve via the throttle valve positioner (M16/1 or M16/6) according to the accelerator pedal position specified by the driver and reduces the ignition timing via the HFM-SFI (N3/4), ME-SFI (N3/10, N3/11, N3/12) control module or the ignition control unit (N3/1).

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 4-cylinder gasoline engine without supercharger:
The HFM-SFI control module (N3/4) cuts off the fuel supply.

 Diesel engine:
The IFI (N3/7), DFI (N3/8) or DCI control module (N3/9) reduces the quantity of fuel.

The ASR or ESP control module (N47-1 or N47-5) continuously checks whether the control functions can be canceled owing to, for example, a sudden improvement in road grip so that the drive torque requested by the driver via the gas pedal can then be made available again.

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MSR engine friction torque control

(not with 4 cylinder gasoline engine without supercharger)

The ASR or ESP control module (N47-1 or N47-5) detects if slip occurs at the drive wheels when the vehicle decelerates.

 4-cylinder gasoline engine with supercharger, 6, 8, and
12-cylinder gasoline engine:
The signal (throttle valve increase) is sent to the EA (N4/1) or ME-SFI control module (N3/10, N3/11, N3/12) via the CAN data bus. The calculated throttle valve opening is controlled by the control module (N4/1, N3/10, N3/11, N3/12) via the throttle valve positioner (M16/1).

 Diesel engine:
The signal (increase fuel quantity) is sent to the IFI (N3/7), DFI (N3/8) or CDI (N3/9) control module via the CAN data bus. The fuel quantity injected is increased by the control module.

With this information, the drive torque can be changed so that no slip occurs at the drive wheels. This improves the lateral stability of the vehicle. This process occurs without notifying the driver (warning lamp A1e21 or A1e41).