It is automatic braking system and it is supposed to stop the wheels skidding when traction is lost
The history is ,it was developed for aircraft to stop the wheels from skidding under brakes (locking up) when ice,snow or wet tarmac surfaces existed
Locked up wheels at landing speeds would tear the undercarriage from the aircraft and result in disaster so the wheels were allowed to turn ( brakes came off) when lost rotary motion was sensed and reapplied when the wheels started to turn again
The application was later developed and refined for auto mobiles under the pretext that when the front wheels locked up directional steering was lost and the vehicle skidded straight ahead and was not controllable to avoid an accident
This in effect was achieved but the advertised lie was that the vehicle stopped quicker
In effect with the wheels being allowed to turn intermittently because of lost traction the stopping distance was increased even though traction was maintained at all times ( try testing the stopping distance when on ice or loose gravel )
Yes it does work when under full brakes on hard dry surface and steering is maintained but unfortunately this perfect scenario doesn't always happen and drivers are left at a lost to understand what went wrong
How does it work
In the brake system there is a electric motorized pump that maintains pressure available to the brake system. When the brakes are applied normally the brake master cylinder supplies pressure to the system and the brakes are applied. The motorized pump is held out of the operation because the brake pressure applied is not sufficient to overcome the valves in the ABS unit and the sensors at the wheels ( segmented rotors) are not activated as a current is being read from the rotor ( in effect a small generator)
Under heavy braking the wheels lock up, the rotors stop generating a current and the ABS swings into action
Now realising that your foot is hard on the brakes, if the pressure to the wheel is lost by a return valve opening (to allow the wheel to turn) the you would immediately have no brakes and the pedal would go to the floor
The motorized pump kicks in and applies pressure to the system ( your pumping the pedal at very fast rate) so that the wheel stops valve opens ,wheel turns , valve closes --repeat operation until the brake pedal is released---stopped
Under heavy brakes you will feel the foot pedal pulsate under the foot because of the valve operation
I effect if you were capable of seeing it in action, the wheel would be operating in a strobe effect--stop-start-stop-start with the wheel in a slightly different position each time you saw it
Modern technology has gone one step further whereby vehicle stability is incorporated into the ABS system ( both use the same wheel sensors) because as the centre of gravity of a body rolling vehicle is changing traction on the tyres and affecting the brake operation , when both are operating together the driver is safer and has more control of the vehicle
Is it important in a vehicle --yes-- if it is remembered that the surface has a lot to do with stopping distance
can you maintain steering ability under heavy brakes --most definitely
does it help in vehicle stability under brake --most definitely
is it required under law if fitted--- take it out of the system and it could amount to jail time in the event of a death
Antilock braking system. It prevents any wheel from locking up so that the car does not swerve in any direction no matter how hard you apply the brakes. It is a safety feature. Each wheel has a sensor on it. Antilock brakes also work automatically when any tire or tires hit a deep puddle of water at higher speeds. The brakes will be applied automatically to the other wheels so that you do not lose control of your car. It pulsates the brakes up to 30 times per second. Never pump the brakes if your car has antilock brakes. ABS does the pumping automatically for you. If you pump the brakes, you may not be able to stop the car fast enough to avoid an accident. It screws up the information that goes to the computer that controls the ABS. Just put steady pressure on the brakes until you come to a stop.
Automatic braking system. stops skidding.
164 views
Usually answered in minutes!
×