When braking, ABS can quickly judge the locked state of the wheel according to the speed signals from each wheel speed sensor, close the normally open input solenoid valve on the wheel that starts to lock, so as to keep the braking force unchanged, and if the wheel continues to lock, open the normally closed output solenoid valve.

Because the pipeline directly leads to the brake fluid storage tank, the braking pressure on the wheel moves down quickly, preventing the wheel from being completely locked due to excessive braking force. When the braking state is always at the best point (slip rate S is 20%), the braking effect is the best and driving is the safest.

The brake fluid in the front cavity of the brake master cylinder is dynamic brake fluid, which pushes the reaction sleeve to move to the right, and the reaction sleeve pushes the booster piston to move the brake pedal push rod to the right. Therefore, when ABS works, the driver can feel the vibration of the pedal on his foot and hear some noise.

After the vehicle decelerates, once the ABS computer detects that the wheel locking state disappears, it will close the main control valve and make the system work in the normal braking state.

If the accumulator pressure drops below the safety limit, the red brake fault indicator and the amber ABS fault indicator will light up. In this case, the driver has to use more force to brake the front and rear wheels deeply.

Extended data:

Performance characteristics of ABS:

Anti-lock braking system can improve the safety factor of emergency braking when the vehicle is driving. In other words, cars without ABS are prone to tire lock, that is, the steering wheel can't turn, so the risk factor will increase, which will easily lead to serious consequences.

Single-channel ABS generally controls the two rear wheels in accordance with the principle of low-profile selection. Single-channel ABS can not make full use of the adhesion of the two rear wheels, and the braking distance may not be significantly shortened.

In addition, the front wheel brake is not controlled, and the front wheel will still lock when braking, so the steering maneuverability has not been improved. However, because the two rear wheels will not lock when braking, it can significantly improve the directional stability when braking, and has great advantages in safety, simple structure and low cost, so it is widely used in light trucks.

To sum up, although the ABS device can shorten the braking distance, in addition, the prices of different types of ABS devices vary greatly due to the composition and structure, so when buying a car, we should not only look at the price, but also look at which type of ABS device is installed.

Baidu Encyclopedia-Anti-lock Brake System