Antilock
or Antiskid Device | Anti-lock Breaking System
Antilock or antiskid device
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 antiskid 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.
Antilock brake 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.
Senstronic braking control (SBC)
Senstronic 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.
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