Description Of ESC Control: Notes
ESC system features ABS/EBD, TCS and AYC functions.
ABS/EBD function: The ECU changes the active sensor signal (current shift) coming from the four wheel sensors to the square wave. By using the input of above signals, the ECU calculates the vehicle speed and the acceleration & deceleration of the four wheels. And, the ECU judges whether the ABS/EBD should be actuated or not.
TCS function prevents the wheel slip of drive direction by adding the brake pressure and engine torque reduction via CAN communication. TCS function uses the wheel speed sensor signal to determine the wheel slip as far as ABS function.
AYC function prevents unstable maneuver of the vehicle. To determine the vehicle maneuver, AYC function uses the maneuver sensor signals (Yaw Rate Sensor, Lateral Acceleration Sensor, Steering Wheel Angle Sensor).
If vehicle maneuver is unstable (Over Steer or Under Steer), AYC function applies brake pressure on certain wheel, and sends engine torque reduction signal via CAN.
After the key-on, the ECU continuously diagnoses the system failure (self-diagnosis). If the system failure is detected, the ECU informs driver of the system failure through the BRAKE/ABS/ESC warning lamp (fail-safe warning).
Input and Output Diagram