Antilock System Brake
Question: How does an Antilock brake on a car work? Why is it needed?
Stopping a car in an emergency can be very challenging. One feature used in several vehicles is antilock brakes. When used properly, an antilock brake system (ABS) adds an important measure of safety to your driving, under all conditions. Antilock brakes enhance vehicle stability and steering, and may reduce stopping distances during emergency breaking, particularly on wet or icy roads.
A disc brake, a system previously used in vehicles, uses a piston to squeeze the brake pads against a rotor. Breaking harder increases the magnitude of the normal force, which results in the increase of the force of friction acting on the rotor. Given that the rotor is attached to the steering wheel, as the rotor reduces its speed so does the wheel. With disc brakes on cars, the brake can prevent the wheel from turning lot faster than the friction from the road can stop the car from moving. This can cause the wheels to lock, sending the vehicle into an uncontrollable skid. Wheel lockup can result in longer stopping distances, loss of steering control, and loss of stability if the vehicle begins to spin. The antilock braking system can prevent these potentially life threatening car accidents from occurring.
The ABS is composed of four main components: speed sensors, a pump, valves, and a controller. The speed sensors, which are located at each wheel, provide the ABS with the information of when the wheel is about to lock up. There is a valve in the brake line of each brake controlled by the ABS. On some systems the valve is located in three different positions. In the first position, the valve is open; pressure from the master cylinder is transferred right through to the brake. In the second position, the valve blocks the line, which isolates that brake from the master cylinder. This prevents the pressure from rising further in case the driver pushes the brake pedal harder. In...
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