Dynamic Stability Control

Dynamic Stability Control (DSC) uses brakes and engine torque control to assist in maintaining the yaw stability of the vehicle. While the ignition is switched on the DSC function is permanently enabled, unless it is selected off using the DSC switch.

DSC enhances driving safety in abrupt maneuvers and in understeer or oversteer situations that may occur in a bend. The Anti-lock Brake System (ABS) control module monitors the yaw rate and lateral acceleration of the vehicle, steering input and individual wheel speeds. After processing the incoming signals the ABS control module selectively applies individual brakes and signals for engine torque adjustments to reduce understeer or oversteer conditions.

In general:

• In an understeering situation, the inner wheels are braked to counteract the yaw movement towards the outer edge of the bend.
• In an oversteer situation, the outer wheels are braked to prevent the rear end of the vehicle from pushing towards the outer edge of the bend.

The ABS control module monitors the tracking stability of the vehicle. Firstly it uses the input from the Steering Angle Sensor Module (SASM) about the steering wheel speed. Secondly the yaw rate and lateral acceleration values come from sensors located in the Restraints Control Module (RCM). The tracking stability is compared with stored target data. Whenever the tracking stability deviates from the target data, the ABS control module intervenes by applying the appropriate control strategy.

The following interactions occur in an intervention situation:

• The High Speed (HS) Controller Area Network (CAN) chassis systems bus and Flexray signal to the Powertrain Control Module (PCM), to reduce engine torque.
• The application of braking to the appropriate corner of the vehicle.