Anti-lock braking system
1 – front brake; 2 – rear brake; 3 – front brake disc; 4 – rear brake disc; 5 – brake booster and master cylinder; 6 – brake pipe; 7 – front brake pipe; 8 – rear brake pipe; 9 – brake pedal; 10 – parking brake lever; 11 – Parking brake cable; 12 – ABS control unit (HECU); 13 – Front wheel speed sensor; 14 – rear wheel speed sensor
The anti-lock braking system (ABS) controls the pressure in the hydraulic brake drive of each wheel individually and reduces the fluid pressure in the wheel brake mechanism whose wheel begins to lock.
ABS performs the following functions:
- Improved vehicle control stability when avoiding obstacles even during braking.
- Reducing the braking distance during heavy braking while maintaining vehicle stability and control even when cornering.
The anti-lock braking system operates based on information from four sensors transmitted to the ABS unit. The system controls each wheel separately and reduces the fluid pressure in the wheel brake mechanism whose wheel begins to lock.
The material is reprinted from another resource [HyundaiBook.ru]
Under normal conditions, the standard brake system applies the brakes until the wheel locks up, which is detected by the ABS control unit. When the ABS control unit detects a wheel lock up, it controls each valve to increase or decrease the pressure.
The ABS control unit determines the rotation speed and deceleration rate of each wheel based on information from the wheel speed sensors. When braking, the wheel speed decreases and the ABS unit detects the difference between the vehicle speed and the wheel speed. If the deceleration of some wheels exceeds the expected value, the ABS unit detects the onset of locking and opens the corresponding solenoid valves to reduce the brake fluid pressure. At the same time, the wheel rotation speed increases and the electromagnetic pressure relief valve closes, increasing the brake fluid pressure in the working brake cylinder of the corresponding wheel.
EBD (Electronic brake force distribution)
EBD is additionally used instead of the pressure regulator to ideally distribute pressure to the front and rear brakes to prevent the rear wheels from locking under heavy braking.