Antilock Braking System
An antilock braking system monitors the speed of your car’s wheels, and if wheel lock has been sensed, a sensor transmits to a controller, which releases and engages the brakes up to 20 times per second, avoiding a lockup and assisting you in maintaining control of your automobile.
The vehicle will stop more quickly if the brakes are applied just hard enough to get maximum static friction between the tyres and road. If the brakes are applied harder than this then the wheels will lock, the tyres will skid or slide on the road and a lesser kinetic friction will result. Then braking the vehicle is much less effective.
To prevent skidding and thus provide maximum effective braking several devices have been proposed. Mostly skid control of the rear wheels only is provided. Some others provide control at all the four wheels. What is meant by “control” is this. As long as the wheels are rotating the anti skid device permits normal application of the brakes. But if the brakes are applied so tough that the wheels tend to stop turning and thus a skid starts to develop the device comes into operation and partly release the brakes so that the wheels continue to rotate. Still intermittent braking continues. But it is held to just below the point where a skid would start. The result is maximum braking effect.
Working of Antilock braking system:
The hydraulic unit is the central component of an ABS system. Each of the four wheels has a speed sensor, which measures the rotational speed of the wheel. This information is monitored by an Electronic Control Unit, which opens and closes the magnetic valves at the right time. If a wheel is about to lock under heavy braking, the system continues to reduce the hydraulic pressure on that wheel alone, till the threat of locking is past.
Once the wheel is turning freely again, the hydraulic pressure is increased. This increase and release of pressure continues until the driver reduces the force on the brake pedal or until the tendency to lock is overcome. ABS is incorporated in some of the cars to prevent skidding and to rove braking.
Sensotronic braking control (SBC)
Sensotronic Braking Control is basically a brake-by-wire system which eliminates the need for mechanical linkage between the brake pedal and brake master cylinder. SBS also work in conjunction with ABS to enhance braking.
It was developed by Mercedes in association with Robert Bosch GmbH. Among its most important performance features are the dynamic building up of brake pressure and the precise monitoring of driver and vehicle behavior using sensors. In an emergency situation, SBC increases brake line pressure and readies the brakes, so that they can grip instantly with full force when the brakes are applied.
Additionally, variable brake proportioning offers enhanced safety when braking on bends. SBC controls each wheel individually. When in corners, they apply varying degree of pressure on the inside and outside wheels of a car, and in the wet road condition. The SBC is found in Mercedes Benz E cars.