ABS(Anti-lock Braking System) VS No ABS How and when to apply ABS

ABS(Anti-lock Braking System) is an automobile safety system that allows the wheels on a vehicle to maintain friction with the road surface while braking. ABS(Anti-lock Braking System) control and manages the wheels in a particular way and prevents the wheels from locking up so that uncontrolled skidding or slipping of wheels can be avoid.

ABS(Anti-lock Braking System) was first developed for aircraft use in 1929. A fully mechanical system saw limited automobile use in the 1960s in the racing car. In 1970, Ford added an antilock braking system "Sure-track" to the back wheels of as an option and it became standard in 1971.

History

In 1971, Electronically controlled anti-skid brakes were applied on Toyota Crown. In 1972, Mullar Electronic system were fitted on four wheel drive Triumph 2500.

Ford Scorpio was introduced in 1985, to European market with a Teves electronic system throughout the range as standard.

In 1988, BMW introduced the first motorcycle with an electronic-hydraulic ABS.In 1992, Honda followed suit the launch of its first motorcycle ABS on the ST1100 Pan European.

ABS includes a central electronic control unit (ECU), four , and at least two hydraulic valves within the brake hydraulics. The component is attached to all four wheels. The wheel speed sensors judge the speed of each wheels. The ECU constantly monitors the rotational speed of each wheel. When ABS brakes are applied the Speed sensors and ECU activates and monitors which wheel has the most speed. Brakes are applied to the wheel which has highest speed and brakes are not applied to the wheel which has the lowest speed. Again the system monitors the speed of highest speed wheel and lowest speed wheel. This operation is perform 15 times per seconds . This operation help the wheel to prevent skidding.

ABS generally offers improved vehicle control and decreases stopping distances on dry and slippery surfaces; however, on loose gravel or snow-covered surfaces, ABS can increase braking distance, although still improving vehicle control.

Components of ABS:

Speed sensors
A speed sensor is used to determine the acceleration or deceleration of the wheel. The rotation of the wheel or differential induces a magnetic field around the sensor.
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
The pump in the ABS is used to restore the pressure to the hydraulic brakes after the valves have released it. A signal from the controller will release the valve at the detection of wheel slip.

Controller
The controller is an ECU(Electronic Control Unit ) type unit in the car which receives information from each individual wheel speed sensor, in turn if a wheel loses traction the signal is sent to the controller, the controller will then limit the brake force and activate the ABS modulator which actuates the braking valves on and off.

How to use ABS or When to use ABS

There are many situations and cases which on which usage of ABS depends.

ABS activates when driver applies full force or full brakes. If driver press brakes gently and slowly ABS will not activates.Following are several cases which describes usage, advantages and disadvantages of ABS.
I will discuss many cases, explaining the motion of two cars one with ABS(Red car) and the other without ABS(Blue car). Both cars have same speed and same point of applying brakes.
Case 1: In this situation, the blue cars no ABS and Red car has ABS. Both car will apply brakes at same time. Both car will apply full brakes. While applying full brakes ABS will apply on Red car but no ABS will apply on Blue car and will skid.

You can see, both cars stopped at different point. Blue car while skidding have more distance of stopping than Red car. Red car applied ABS, thus it prevented from skidding.

Case 2:

In this case, only Red car will apply full brakes thus ABS will be applied on it. But Blue car will not apply full brake. It will only apply brakes gently so that wheels don't skid.

Here you can see that Blue car didn't skid and stopped before the Red car because when ABS applied on Red car its opposed wheels to stop so that wheels don't skid.

Case 3:

In this case, Both cars will not apply full brakes. It means both cars will apply brakes gently so that wheels don't skid on Blue car and ABS is not applied on Red car.

You can see both cars stopped at the same points.Because Wheel did't skid on Blue car and ABS not Applied on Red cars and wheels were allowed to stop properly.

Case 4: (Benefits of ABS)

In this case, I will show you that when should you apply ABS on your case. You will see benefits of ABS.

You can see there are hurdles in between the road. Both cars have same speed and suddenly hurdles came in front of cars.

You can see when blue car applied full brakes instantly, the wheels skid, friction and contact between road and wheel removed and driver lost control of handling and hit the hurdles. While ABS activated on Red car and friction and contact of wheel remained with road and handling has full control. Thus, Red car is safe from hitting the hurdles.