7.4.2 Anti-lock braking system operation
The system operates as follows: the control module constantly receives signals from the speed sensors of each wheel. As soon as an emergency situation arises and the driver presses the brake pedal sharply, the wheel or wheels will start to be locked. A signal will be sent from the corresponding sensor or sensors to the electro-hydraulic module. This module will open the required valve or valves, which will reduce the pressure in a particular line or lines, and the wheel or wheels are unlocked. At the same time coupling of wheels with road, and consequently, and controllability at braking remain. But it is impossible to keep the wheel decelerated indefinitely. Thus, in the hydraulic module the valves close again, the pressure increases until the wheel starts to lock, and the process is repeated again.
Note
In case if your car is equipped with an anti-lock braking system, you will feel a slight (and sometimes not very) tremor when you press the brake pedal abruptly in case of an emergency. Under no circumstances you shall release the brake pedal in such a situation. On the contrary, you shall try to push it even more or at least leave it in this position.
Note
The anti-lock braking system, first of all, is called to keep control over driving. Not all surfaces the anti-lock braking system will shorten the braking distance during its operation. In most cases, the braking distance may increase slightly. But most importantly, the driver will be able to maneuver, and avoid the collision.
The anti-lock braking system gave a powerful impulse to the automotive industry, because the active safety systems, that started coping in situations involving the demolition, skidding of the car, control of its stability were invented on its basis (this will be discussed below). In such systems, the basis is the same as in the anti-lock braking system, only the number of sensors was increased.
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