The anti-lock brake system ABS stands for Anti-lock Bra […]
The anti-lock brake system ABS stands for Anti-lock Braking System and can be installed on any car with hydraulic brakes. It uses a rubber airbag in the valve body. When the brake is pressed, the brake oil pressure is applied to the valve body of the ABS. At this time, the airbag uses the middle air compartment to return the pressure, so that the wheel avoids the locking point. If the front wheels are locked, the driver cannot control the direction of travel of the vehicle. If the rear wheels are locked, the side slip phenomenon is very likely to occur.
A speed sensor is placed on each wheel in the ABS, and signals about the rotational speed of each wheel are input to the electronic control unit. The electronic control device monitors and determines the motion state of each wheel according to the signal input by each wheel rotation sensor and forms a corresponding control command. The hydraulic solenoid valves are not energized and are in the off state, the electric pump is not energized, and the brake pipes from the brake master cylinder to each brake wheel cylinder are in communication state, and each brake wheel cylinder is connected to the accumulator. The brake lines are all closed, and the brake pressure of each brake wheel cylinder will change with the output pressure of the brake master cylinder. The braking process at this time is exactly the same as that of the conventional brake system.
During the braking process, when the electronic control device determines that the wheel tends to lock according to the wheel speed signal input by the wheel speed sensor, the ABS enters the anti-lock brake pressure adjustment process. For example, when the electronic control device determines that the right front wheel tends to lock, the electronic control device energizes the liquid intake solenoid valve that controls the right front wheel brake pressure, and turns the right forward liquid solenoid valve into the closed state, and the brake master cylinder outputs The brake fluid no longer enters the right front brake wheel cylinder, and the electronic control device causes the right forward liquid solenoid valve and the outlet solenoid valve to be powered off, so that the liquid inlet solenoid valve is turned into the open state, and the liquid discharge solenoid valve is turned into the closed state. The state also enables the electric pump to be energized to send brake fluid to the brake wheel cylinder, and the brake fluid output by the brake master cylinder and the brake fluid pumped by the electric pump pass through the right forward liquid solenoid valve that is in an open state. Entering the right front brake wheel cylinder, the brake pressure of the right front brake wheel cylinder is rapidly increased, and the right front wheel begins to decelerate.