Anti-lock braking system (ABS) — design description

The ABS system controls the stability and control of the vehicle during hard braking. Vehicles with ABS are equipped with four sensors on the front and rear wheels, allowing independent control of the left and right sides of the vehicle. The ABS system includes the following subsystems: electronic brake force distribution system (EBD), which controls the braking force of the rear wheels; a safe mode feature that enhances the level of security.

The EBD system, guided by data on the rate of deceleration of the car and on the slippage of the wheels, controls the solenoid valves, increasing or decreasing the pressure of the TJ in the rear brakes. In this way, EBD improves both the vehicle's braking power and its handling and stability. Also, thanks to EBO, the driver does not need to depress the brake pedal harder in a more loaded car or when driving on slippery surfaces.

Thanks to the optimal distribution of braking forces between the axles, the load on the front brakes is reduced, which increases the life of the brake pads and discs.

Specifications

Position	Specification
ABS control method	4 sensors
The number of teeth of the front and rear ABS sensor rotors	47
Wheel speed sensor type	electromagnetic
Gap between sensor and front wheel rotor (unregulated)	0.25-1.40mm
Gap between sensor and rear wheel rotor (unregulated)	0.18-0.92mm

ABS controls

Control elements of the ABS system shown in fig. M2 7.046

№	the name of detail	Function Description
Sensors
1	Wheel speed sensors	Determines the rotation speed of each wheel
2	Stoplight switch	When the brake pedal is pressed, it turns on the brake light
3	Acceleration sensor (four-wheel drive)	Determines the acceleration in the direction the vehicle is moving
Executive devices
4	Electronic hydraulic unit	Operates solenoid valves
5	ABS system malfunction warning light	Turns on in case of a malfunction in the system
6	Brake system malfunction warning light	Turns on in case of a malfunction in the system
7	Diagnostic connector	Used to connect diagnostic devices
8	Electronic control unit for anti-lock braking system (ABS-ECU)	Processes data from sensors and controls actuators. Performs self-diagnosis

Block diagram of the ABS system