ANTILOCK BRAKING SYSTEM

ANTILOCK BRAKING SYSTEM

Abstract:

About 40% of all car accidents involve skidding. The most efficient braking takes place when the wheels are still revolving. If the brakes lock the wheels so that the tires skid, kinetic friction results, and braking is much less effective. 
ABS is essentially an enhanced or improved version of ordinary brakes. Simply put, the ABS system is designed to prevent the brakes from locking up and skidding when braking hard or when braking on wet or slick surfaces. This adds a significant margin of safety for everyday driving by preventing dangerous skids and allowing the driver to maintain steering control while trying to stop.
An ABS system essentially consists of four main parts, the wheel speed sensor, the control module, the hydraulic modulator and the pump and accumulator. The wheel speed sensors which sense the relative change of speed of the wheels & simultaneously send signals to the control module. The control module is a microprocessor which modulates brake pressure as needed. The hydraulic modulator consists of solenoid valves from which the hydraulic fluid flows. A high pressure electric pump is used to generate high pressure & the high pressure fluid is stored in the accumulator.  
Directional stability also depends on traction. As long as a tire doesn’t slip, it will roll only in the direction it turns. But once it skids, its directional stability gets reduced very much. By minimizing the loss of traction, antilock braking helps maintain directional stability and steering control.
Another point to keep in mind about ABS is that it’s essentially an "add-on" to the existing brake system. It only comes into play when traction conditions are marginal or during sudden "panic" stops. The rest of the time, it has no effect on normal driving or braking.
ABS systems are also designed to be as "failsafe" as possible. Should a failure occur in the ABS control electronics, most systems will deactivate themselves. The ABS warning light will come on, but the vehicle should still have normal braking. This doesn’t necessarily make the vehicle unsafe to drive, but it does mean the ABS system won’t be there if needed in an emergency.