Briefly describe how ABS works?
1 Answers
ABS system, also known as the Anti-lock Braking System, works as follows: During braking, the ABS system, based on speed signals from each wheel speed sensor, closes the normally open input solenoid valve for the wheel that is starting to lock up, keeping the braking force constant. If the wheel continues to lock, the normally closed output solenoid valve is opened. This ensures the braking state remains at the optimal point, achieving the best braking effect and maximum driving safety. ABS, short for Anti-lock Braking System, functions by automatically controlling the braking force during vehicle braking to prevent wheel lock-up. It keeps the wheels in a state of rolling and sliding (with a slip ratio of about 20%), ensuring maximum traction between the wheels and the road. The ABS system mainly consists of four components: wheel speed sensors, electronic control unit (ECU), hydraulic unit, and ABS warning light. The wheel speed sensors detect the motion state of the wheels and generate sinusoidal electronic pulse signals. These signals are then processed by a modulator, converted into digital signals, and transmitted to the electronic control unit. The electronic central control unit (ECU) receives input signals from the wheel speed sensors and uses these parameters to calculate the wheel speed, vehicle speed, and slip ratio. Based on the slip ratio, it determines the wheel state and issues control commands to the hydraulic unit. The hydraulic unit adjusts the pressure in the brake lines according to the control commands. The adjustment process includes maintaining pressure, increasing pressure, and reducing pressure. The ABS warning light alerts the driver to any system malfunctions. If the ABS warning light comes on, it is advisable not to continue driving. An illuminated ABS light indicates a malfunction in the vehicle's anti-lock braking system. During emergency braking, if the wheels lock up, the vehicle may skid uncontrollably, making it difficult for the driver to slow down or adjust the vehicle's trajectory, posing significant safety risks.
