PBS prevents the wheels from blocking during heavy braking. At the same time, the braking distance is reduced, because. the force circuit between the wheels and the road surface is greater if the wheels rotate during braking. In addition, the car remains manageable.
PBS is made as a device with three circuits. This means that the front wheels are steered independently of each other. The rear wheels are steered together, with steering determined by the wheel more likely to lock up.
PBS is ready for action after turning on the ignition and reaching a speed of 5-7 km / h. It affects the braking processes as soon as the speed once reaches 12 km/h.
Speed sensors on all four wheels measure wheel speed. By processing the signals from the individual sensors, the control unit calculates an average speed that approximates the speed of the vehicle. By comparing the speed of rotation of the individual wheels with the average speed, the control device determines the degree of slippage of the individual wheels and can thus determine the moment when one of the wheels comes close to blocking.
As soon as one of the wheels approaches blocking, the pressure of the brake fluid in the brake pad or, respectively, in the brake cylinder becomes too high in relation to the adhesion of the tires to the road, and the hydraulic system, under the influence of signals from the control device, maintains the brake fluid pressure stable. This means that the pressure in the brake cylinders does not increase even with further pressure on the brake pedal. If the danger of blocking remains, then by opening the exhaust valve the pressure is reduced, but only to such a level that the wheel begins to rotate a little again, after which the pressure is again maintained stable.
If the wheel starts to rotate faster to a certain extent, the hydraulic system increases the pressure, but not more than the total pressure in the brake system.
This process is repeated during hard braking for each braking circuit until the brake pedal is released or the vehicle speed drops to 2-3 km/h.
The safety circuit of the electronic control device ensures that the PBS in the event of a malfunction (e.g. cable break) or if the battery voltage is too low (below 10.5 volts) turned off automatically. In this case, while driving, the PBS control signal lights up on the instrument panel.
If the PBS warning light comes on while driving, this indicates that the anti-lock braking system has been disabled.
- stop the car, turn off and start the engine again.
- check battery voltage. If it is below 10.5 volts, charge the battery.
Attention! If the PBS control signal lit up at the beginning of the ride, and after some time it went out again, this indicates that the battery voltage was too low, but then increased due to recharging from the generator.
- check the strength of the connection of the terminals to the battery.
- raise the car, remove the front wheels, check the electrical wires for external damage (grinding).
- further verification should be entrusted to the workshop.
Attention! Before welding with electric welding, the plug must be disconnected from the control unit. Disconnect the plug only when the ignition is switched off. When varnishing, the control device may be subjected to short-term exposure to temperatures not exceeding 95 degrees. C or long (about 2 hours) up to 85 degrees.
(1) hydraulic block
(2) relay
(3) control device
(4-8) brake wires
(47-447) the electronic control unit and the hydraulic unit are integrated under the driver's seat.
(1) speed sensor (front)
(2) impulse wheel
(3) brake booster
(4) control lamp PBS
(5) speed sensor (rear)
(6) impulse wheel
(7) hydraulic block
(8) brake force regulator
(9) control device
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