15.9.1. Removal and installation of the vacuum amplifier on the car equipped ABS

On cars Sharan the antiblocking system of manufacture of company ITT Teves is established as the serial equipment.

System ABS raises active safety of the car and interferes with blocking of wheels at sharp braking. Thus the car to a full stop keeps controllability, without drift.

Structure AVS includes standard system of braking, gauges of frequency of rotation of wheels, the hydraulic block, the electronic block of management (ЭБУ–АВS) and a plait of electric wires.

Gauges of frequency of rotation of wheels of system AVS hand over the information in the form of an alternating voltage electric current about frequency of rotation of wheels on ЭБУ–АВS. Gauges of frequency of rotation of forward wheels are placed on rotary fists, and back wheels — on pins.

ЭБУ–АВS On signals from all four gauges of frequency of rotation of wheels measures acceleration, delay or sliding of each wheel. Comparing speed of rotation of each wheel to average speed of all wheels, ЭБУ–АВS defines degree проскальзывания separate wheels and by that can establish the moment when one of them approaches close to blocking, and on the basis of this information gives out operating impulses on electromagnetic the valve of the hydraulic block. As soon as one of wheels approaches to blocking, pressure of a brake liquid in its support becomes too high in relation to coupling of the tyre with road. The hydraulic system under the influence of management signals supports pressure of a brake liquid the stable. It means that pressure in a support does not raise even by the further pressing a brake pedal. If danger of blocking remains, thanks to opening of the final valve pressure decreases, but only to such level when the wheel again starts to be accelerated a little then pressure is again supported to constants.

If the wheel starts to rotate faster ЭБУ–АВS gives out a signal on pressure increase, but not above the general pressure in brake system. The driver feels action АВS on a pulsation of a brake pedal and a characteristic sound of work of the hydroblock in a motor compartment that signals it about movement in boundary conditions.

The hydroblock is established on a brake highway after the main brake cylinder. On each of four pipelines approaching to the hydroblock the electromagnetic valve which takes away a brake liquid to the electropump providing brake pressure in a highway of a concrete wheel is established.

At malfunction of system AVS EBU-AVS stops development of operating impulses, and in a combination of devices control lamp АВS constantly burns. System AVS Failure allows to move to the car, but demands большего attention to speed of movement and road conditions as the management efficiency sharply decreases.

The prevention All works on system AVS are spent at the switched off ignition and the removed plug «–» АБ. Before works with use of the electrowelding equipment расстыкуйте штекерную колодку ЭБУ–АВS.

The prevention Check АВS, repair of the block of valves, ЭБУ–АВS or pipelines spend on HUNDRED.