Auto Manual of VW Passat B5

10.3. Systems ABS/EBV/EDS/ASR/ESP

THE GENERAL DATA

ABS. Antiblocking system of brakes

Efficiency of braking the greatest, when coupling of the tyre with a surface of road the maximum. In the course of braking the tyre slides on a surface, and district speed of a wheel becomes less speeds of the car.

Sliding minimum (0 %) when the wheel slides freely, and maximum (100 %) when the wheel is blocked. Peak efficiency of braking is reached, when sliding makes 15 %. This size also allows to keep stability and controllability of the car.

The role of antiblocking system consists in restriction of the pressure created in hydraulic system of brakes so that the sliding size was kept about optimum size (15 %). Action of this system should be immediate and separate for each wheel. The system should answer immediately each change of a surface (coupling factor) and loading on the car.

In antiblocking system of firm TEVES (ATE) in one unit functions of power supply, a drive of brakes and the vacuum amplifier, and also management of antiblocking of wheels are carried out. The hydraulic block is established instead of the serial established vacuum amplifier with the built in main brake cylinder. Installation ABS is possible only at factory at manufacturing of the car and cannot be established in addition. The antiblocking system interferes with blocking of wheels at sharp braking. Thanks to it the brake way decreases, especially at low coupling with a road covering at a rain and snow. Cohesive force between wheels and road in this case is more, when at wheel braking continue rotation. Besides it even at full braking the car remains operated. Gauges of turns, on one on each wheel, measure speed of rotation of a wheel. On signals from gauges of turns of a wheel in the electronic operating block the average speed approximately corresponding to speed of movement of the car is calculated. Comparing speed of rotation of each separate wheel with the average calculated speed, the electronic block defines a condition проскальзывания a separate wheel and by that establishes, what wheel is in a preblocking condition.

When one of four gauges of speed of rotation will transmit a signal about blocking of a corresponding wheel, immediately the electronic actuation device gives out a closing signal to I correspond щему to the inlet electromagnetic valve which immediately blocks giving of a brake liquid through the brake pipeline to a brake of this wheel – force of braking remains to a constant. If nevertheless sliding proceeds, the final valve and pressure in hydraulic system of the given brake opens decreases – the wheel is not braked (surplus of a brake liquid comes back in a tank). As soon as the wheel again will start to rotate, at once there is an opening of the inlet valve and closing of the final valve. Pressure increases in a contour, and the wheel is again braked.

Such cycle of braking and free rotation of a wheel occurs very quickly (some times in a second) and proceeds to a stop cars or to отпускания brake pedals.

This process repeats at sharp braking separately for each wheel until the pedal of a brake will be released or at reduction of speed of the car to 2–3 km/hour. The driver defines work ABS on a pulsation of a pedal of a brake.

The system of emergency switching-off provides system ABS switching-off at any malfunction or at a low voltage in an electric network of the car (more low 10В). The electronic actuation device carries out also автодиагно стическую function, warning the driver fire of a control bulb about registration of malfunction of electric chains or elements of antiblocking system. At faulty system ABS of a brake, nevertheless, are serviceable and function as if this system is not present in the car.

EBV. The electronic distributor of brake effort on back wheels

The electronic distributor of brake effort carries out functions механическо го a pressure regulator, but works more precisely and has wider range of adjustment. At car movement on a straight line giving of a brake liquid to brakes of back wheels is completely open. For maintenance of stable passage of turns with braking giving of a brake liquid to back brakes is limited. On the basis of signals of gauges of rotation of wheels of system ABS the block of management EBV defines, when the car moves in turn. At passage by the car of turns the brake effort transferred to back wheels, decreases, therefore the probability of drift of the car decreases.

EDS. Electronic blocking of differential

Being addition to elements ABS, EDS reduces transfer of a twisting moment of the engine at adverse traffic conditions, especially on liftings and at car accelerations, eliminating proslipping of one of driving wheels. Thanks to mechanical blocking of differential improvement of transfer of a twisting moment as thus the party with great value of factor of a friction can transfer больший a twisting moment is reached.

The electronic block of management receives the information from gauges ABS about speed of rotation of driving wheels and constantly compares them. In the presence of a difference of number of turns from above about 110 rpm EDS joins automatically and reduces twisting moment transfer by a revolving wheel until it will not have about the same speed, as not slipping wheels. Thanks to such management reaches ся that to a wheel with the best conditions of coupling with road the increased twisting moment is transferred. EDS it is automatically disconnected at speed of movement of the car above 40 km/h, and also at passage of turns and at overheating of brakes.

ASR. System of reduction of a twisting moment of the engine transferred to driving wheels

Twisting moment reduction at пробуксовывании both driving wheels is carried out by decrease in capacity of the engine. In this case capacity of the engine is limited so that the twisting moment necessary for movement of the car was transferred only.

System ASR should be always included. Only in certain unusual cases when proslipping of wheels is desirable, it is preferable to switch off system.

ESP. Electronic system of stabilisation

By means of stabilisation system the control over dynamics of the car in limiting modes is carried out, for example, at overcoming of turns on high speed. Danger of a pulling down or car drift essentially decreases at all possible conditions of a road covering.

In electronic system of stabilisation are integrated antiblocking system of brakes and пробуксовочные systems. In electronic system of stabilisation sizes of accelerations are in addition measured in a cross-section plane, pressure in system of a drive of brakes and an angle of rotation of operated wheels speed of moving of a body round a vertical axis. On the basis of the data about an angle of rotation of operated wheels and speed of the car defines that direction in which the driver of the car intends to move, and it is constantly compared with actual behaviour of the car. At a nonagreement of these factors when the pulling down or car drift begins, the stabilisation system automatically brakes a certain wheel.

In the presence of malfunction the electronic control system is automatically disconnected, thus on a combination of devices control lamps light up. In this case the brake system works in a usual mode.

If during movement control lamps ABS and EBV light up, keep in mind that at sharp braking there can be a blocking of back wheels.

Fire of one or several control bulbs during movement signals about system switching-off. Thus it is necessary to execute following actions.

PERFORMANCE ORDER

1. Stop the car, switch off and start the engine. 2. Check up pressure of the accumulator. If it more low 10,5 In, charge the accumulator. The prevention If control lamp ABS burns in the trip beginning, and then dies away, it testifies that pressure was an admissible limit for work ABS, but then has raised as a result of generator work. 3. Check up a condition of plugs of the accumulator. 4. Lift the car, remove wheels and check up serviceability of electroconducting of gauges of speed of rotation of wheels. 5. If malfunction is not eliminated, the further check is necessary for making at servicing deport.