Kia Clarus/Credos

1995-2001 of release

Repair and car operation

KIA Klarus
1.1. Periodicity of maintenance
+ 2. FE DOHC engines and Т8 DOHC
+ 3. Greasing system
+ 4. Cooling system
+ 5. Power supply system and release
+ 6. Fuel system
+ 7. Ignition system
+ 8. Coupling
+ 9. Mechanical transmission
+ 10. АКП G4A–EL
+ 11. АКП 50–40 LE
+ 12. Axes and power shafts
+ 13. Steering
+ 14. Wheels and tires
+ 15. Suspension bracket
+ 16. Body
+ 17. Central air
+ 18. Electric equipment
- 19. Brake system
   19.1. Specifications
   19.2. Pumping of hydraulic system of a drive of brakes
   19.3. Check of brake tubes and hoses
   19.4. Replacement of brake hoses
   19.5. Height of installation of a pedal of a brake
   19.6. Free wheeling of a pedal of a brake
   19.7. Distance of a pedal of a brake from a floor
   19.8. Brake pedal
   19.9. Check of the switch of a stoplight
   19.10. Main brake cylinder
   19.11. Check of the vacuum amplifier of brakes
   19.12. Forward disk brake
   19.13. Back disk brake
   19.14. Pressure regulator
   19.15. Parking brake
   19.16. Anti-blocking system of brakes (ABS)
   19.17. List of codes of malfunctions of brake system
   19.18. Precautions at carrying out repair
   19.19. Pumping of hydraulic system of a drive of brakes
   19.20. Hydraulic control unit (HCV)
   19.21. ABS control unit
   19.22. Sensors of frequency of rotation of a wheel
   19.23. Rotor of the forward sensor
   19.24. Main survey
   19.25. Check of functionality
   19.26. Search and elimination of malfunctions
+ 20. Electric circuits

19.16. Anti-blocking system of brakes (ABS)

GENERAL INFORMATION

Arrangement of elements of anti-blocking system of brakes (ABS) on the car

1–block of hydraulic management of HCV;
2–ABS control unit;
3–main relay;
4–engine relay;
5–sensor of frequency of rotation of a wheel;
6–sensor of frequency of rotation of a wheel;

7–pressure regulator;
8–connector;
9–engine socket;
10-socket of the block of hydraulic management of HCV.

Principle of work of brake system

1–ABS control unit;
2–sensor of speed;
3–electric pump;
4–reserve tank of brake system;
5–main brake cylinder;
6–vacuum amplifier of brakes;
7–pressure accumulator;

8–brake pedal;
9–primary piston;
10-central valve;
11-inlet valve;
12-sensor of frequency of rotation of a wheel;
13-support;
14-final valve.

Hydraulic scheme of brake system

1–vacuum amplifier of brakes;
2–main brake cylinder;
3–central valve;
4–reserve tank;
5–sensor of level of brake liquid;
6–pressure accumulator;

7–pump;
8–engine;
9–inlet valve (BUT);
10-inlet valve (BUT);
11-final valve (NZ);
12-final valve (NZ).

The anti-blocking system of brakes is intended for an exception of blocking of wheels at intensive braking.

Main ABS functions:

– reduction of a brake way at the expense of an exception of blocking of wheels at intensive braking;
– improvement of stability of driving in the course of braking.

The three-channel anti-blocking system with four sensors works in such a manner that each of forward wheels copes independently, and back wheels cope by a principle of a choice of the smallest speed (management of hydraulic pressure is made from that party from which sliding came earlier).

Principle of work of ABS

Braking is carried out as in usual brake system until the ABS control unit will not find out that the wheel is blocked.

In a standard mode of braking electromagnetic valves do not work, the inlet valve is normally open, and final – is normally closed.

When ABS works, the hydraulic device operated by the ABS control unit, operates each valve in three stages, supporting, reducing or increasing pressure.

The ABS control unit by means of sensors of frequency of rotation of wheels fixes frequency of rotation and delay of each wheel. At braking implementation frequency of rotation of wheels decreases and calculated a difference between frequency of rotation of a wheel and speed of the car. If delay of frequency of rotation of some wheels exceed expected value (a point And), the ABS control unit considers that there was a blocking of the corresponding wheel and opens the final electromagnetic valve to reduce pressure of brake liquid. If pressure of blocking on the corresponding wheels is exceeded (a point In) and frequency of rotation of a wheel increased to a point With, the ABS control unit again closes the final valve to increase pressure of brake liquid.

Principle of work of ABS

In cars with ABS the following symptoms testifying, however, to serviceable work of ABS can be observed.

Symptom	Description
Motor noise	At management of the hydraulic ABS device noise can be audible.
Noise from suspension bracket system	As at ABS work braking is carried out in three stages, from system of a suspension bracket noise can be audible.
Fluctuations of a pedal of a brake	At work of ABS there is an easy fluctuation (release) of a pedal of a brake.

1. Standard braking (braking without ABS)

By pressing a brake pedal under the pressure of the liquid, the raised vacuum amplifier of brakes, closes the central valve of the main brake cylinder and pressure in the hydraulic highway of a brake is created. During this moment the inlet electromagnetic valve is open, the final valve is closed and hydraulic pressure from the main cylinder is transferred to the wheel cylinder.

2. Braking with ABS

2.1 Pressure maintenance

After the ABS control unit found out that wheels are blocked because of excessively increased pressure, the ABS control unit closes the inlet valve to prevent further increase in pressure.

2.2 Pressure reduction

If wheels are still blocked, the ABS control unit opens the final valve that brake liquid could arrive in the pressure accumulator therefore pressure will decrease. Pressure decreases only in brakes of the blocked wheels.

2.3 Increase in pressure

If the wheels which were blocked, again started to rotate with demanded frequency of rotation, the ABS control unit stops to operate the electromagnetic valve, passing to a standard mode of braking.