ESC is an important safety system that prevents critical vehicle states from developing. ESC is also the prerequisite for other safety technologies, such as driver assistance systems.
The ESC system constantly evaluates the data from the wheel speed sensors, steering angle sensor, yaw rate, and lateral acceleration sensor and compares the driver’s input with the vehicle’s actual behavior.
If an unstable state is detected, for instance as the result of a sudden direction change, ESC responds in milliseconds and stabilizes the vehicle through wheel-specific brake intervention and adjustment of the engine torque.
The ESC systems offer analog-controlled, infinitely variable valves for minimal pedal vibration and optimally dosed pressure build-up in the automatic braking process of Adaptive Cruise Control (ACC) right up to bringing the vehicle to a complete standstill in stop-and-go traffic.
ESC intervenes when the car threatens to oversteer by braking the outer wheels of the car. As a general rule, most of the brake force goes to the front of the wheel, where wheel slip is set at about 50 percent. This gives rise to a counter torque which compensates the yawing torque that causes oversteer.
ESC intervenes when the car understeers and seeks to drift straight ahead in a curve. Here, ESC brakes the inside wheels, applying the largest brake force to the rear wheel.