Anti Lock Braking System ABS in Mazda

The ABS System

The theory behind anti-lock brakes is simple. A skidding wheel (where the tire contact patch is sliding relative to the road) has less traction than a non-skidding wheel. If you have been stuck on ice, you know that if your wheels are spinning you have no traction. This is because the contact patch is sliding relative to the ice (see Brakes: How Friction Works for more). By keeping the wheels from skidding while you slow down, anti-lock brakes benefit you in two ways: You'll stop faster, and you'll be able to steer while you stop.

There are four main components to an ABS system:

• Speed sensors
• Pump
• Valves
• Controller

­Speed Sensors
The anti-lock braking system needs some way of knowing when a wheel is about to lock up. The speed sensors, which are located at each wheel, or in some cases in the differential, provide this information.
Valves
There is a valve in the brake line of each brake controlled by the ABS. On some systems, the valve has three positions:

• In position one, the valve is open; pressure from the master cylinder is passed right through to the brake.
• In position two, the valve blocks the line, isolating that brake from the master cylinder. This prevents the pressure from rising further should the driver push the brake pedal harder.
• In position three, the valve releases some of the pressure from the brake.  
  Pump
  Since the valve is able to release pressure from the brakes, there has to be some way to put that pressure back. That is what the pump does; when a valve reduces the pressure in a line, the pump is there to get the pressure back up.
  Controller
  The controller is a computer in the car. It watches the speed sensors and controls the valves.
  ABS at Work
  There are many different variations and control algorithms for ABS systems. We will discuss how one of the simpler systems works.
  The controller monitors the speed sensors at all times. It is looking for decelerations in the wheel that are out of the ordinary. Right before a wheel locks up, it will experience a rapid deceleration. If left unchecked, the wheel would stop much more quickly than any car could. It might take a car five seconds to stop from 60 mph (96.6 kph) under ideal conditions, but a wheel that locks up could stop spinning in less than a second.
  The ABS controller knows that such a rapid deceleration is impossible, so it reduces the pressure to that brake until it sees an acceleration, then it increases the pressure until it sees the deceleration again. It can do this very quickly, before the tire can actually significantly change speed. The result is that the tire slows down at the same rate as the car, with the brakes keeping the tires very near the point at which they will start to lock up. This gives the system maximum braking power.
  When the ABS system is in operation you will feel a pulsing in the brake pedal; this comes from the rapid opening and closing of the valves. Some ABS systems can cycle up to 15 times per second.

lyrics in tamil-அம்மன் கோவில் கிழக்காலே சூப்பர் ஹிட் பாடல் உன் பார்வையில் ஓராயிரம்

உன் பார்வையில் ஓராயிரம்
கவிதை நான் எழுதுவேன் காற்றில் நானே
நிதமும் உன்னை நினைக்கிறேன்
நினைவினாலே அணைக்கிறேன்
(உன் பார்வையில்)

அசைந்து இசைத்தது வளைக்கரம்தான்
இசைந்து இசைத்தது புது சுரம்தான்
சிரித்த சிரிப்பொலி சிலம்பொலிதான்
கழுத்தில் இருப்பது வலம்புரிதான்
இருக்கும் வரைக்கும் எடுத்துக்கொடுக்கும் (2)
மனதை மயிலிடம் இழந்தேனே
மயங்கி தினம் தினம் விழுந்தேனே
மறந்து பிறந்து பறந்து தினம் மகிழ
(உன் பார்வையில்)

அணைத்து நனைந்தது தலையணைதான்
அடுத்த அடியென்ன எடுப்பது நான்
படுக்கை விரித்தது உனக்கெனத்தான்
இடுப்பை வளைத்தெனை அணைத்திடத்தான்
நினைக்க மறந்தாய் தனித்துப் பறந்தேன் (2)
மறைத்த முகத்திரை திறப்பாயோ
திறந்து அகத்திடை இருப்பாயோ
இருந்து விருந்து இரண்டு மனம் இணைய
(உன் பார்வையில்)

Two Suns Caught on Tape---Unbeleivable