SAURABH CHAUHANME III YEAR(120970104045) -THDC-IHET (UTTARAKHAND)

What Is An ABS?• Anti Lock Braking System is an important

safety equipment in the vehicle which provides proper traction to the tyres of the vehicle by preventing them to get locked in case of sudden hard braking and hence provides steering ability to the driver and consequently better control of the vehicle.

Why ABS?• It is quite unnoticed that

when wheels get locked on sudden hard braking, the driver is not able to steer the vehicle.ABS provides the ability to steer the vehicle on wheel lock up.

COMPONENTS OF ABS• SPEED SENSOR Speed sensor continuously monitors all the

four wheels(if vehicle equipped with 4 channel,4sensor ABS) and sends the electric signal to ECU or ABS ECU.

COMPONENTS OF ABS• PUMP & VALVES The function of valves is to release pressure of the

brake lines when ECU signals it. 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.

COMPONENTS OF ABSIn position three, the valve releases some of

the pressure from the brake.Pump’s function is to restore pressure in the

brake lines every time the valve releases it.

COMPONENTS OF ABS• ELECTRONIC CONTROL UNIT(ECU)The function of ECU is to control the valve and

pump actions and to receive the signal from the speed sensor.

It acts as a brain of the ABS. Apart from being an integral part of ABS,it

performs all the other automation work in the vehicle viz : Electronic fuel injection(EFI) etc.

Illustration Of ABS

Block Diagram Of An ABS Master

Cylinder ABS ECUPedal force

WHEEL

SPEED SENSOR

Brakelines

Brake Lines

Continuous Electric Signal To ECU By Speed Sensor.

Monitorswheel

Types OF ABS• Four Channel, Four SensorIn this type, there are four sensors and four

separate valves which monitor all the four wheels individually.

This is regarded as the best scheme of arrangement as it provides efficient monitoring of all four wheels and hence maximum efficiency.

Types OF ABS• Three Channel, Three SensorIn this type of arrangement, two seperate

sensor and valves monitor front two wheels while single sensor and valve monitors rear two wheels.

This arrangement is also good but not as efficient as 4 channel 4 sensor.

Types OF ABS• One Channel,One SensorIn this type of arrangement, only rear two

wheels are monitored by a single channel and single valve.

This is the least used arrangement and provide least safety.

Also known as REAR WHEEL ABS.

Types OF ABS

How Does It Really Work?• SPEED SENSOR monitors wheel lock up

condition every second.• Whenever driver applies brake and if SPEED

SENSOR detects wheel lock up conditon, it sends the electric signal to ECU which sends the signal to VALVE(which releases pressure) and PUMP(which recreates pressure) and together by releasing and pumping pressure quickly prevents wheel lock up.

APPLICATION OF ABS• ABS is effective on dry concrete roads as it

reduces stopping distance of the vehicle..

APPLICATION OF ABSBETTER CORNERING STEERING ABILITY

APPLICATION OF ABSBetter Vehicle stability in case of different road conditions

EFFECTIVENESS OF ABS

• Prior to equipping cars with ABS, the braking system was tested extensively and showed a ten metre reduction in the distance required for drivers travelling at 97 km/h to come to a complete stop.

• In addition, the National Highway Transportation Safety Administration (NHTSA) found that stopping distances on wet pavement were 14% longer for vehicles without ABS (51m with for cars with ABS vs. 58m for cars without it).

EFFECTIVENESS OF ABS

• The same kind of decrease in stopping distance was not seen on dry pavement (only a 5% decrease in stopping distance was noted for vehicles with ABS).

• In addition, under controlled test conditions, it was found that 58% of drivers without ABS strayed from their intended path, whereas only 24% of drivers with ABS did the same.

• Effectiveness of ABS is best on wet road condition.

USE OF ABS

SOURCE: INTERNET

ADVANTAGES OF ABS• It provides steering ability to the driver in case of

wheel lock up.• It provides better control of the vehicle in wet road

conditions.• It provides better cornering.• It reduces stopping distance of the vehicle(not

necessarily).• Overall it is an essential safety feature when used

wisely.• It reduces insurance cost of the vehicle(not

necessarily).

DISADVANTAGES OF ABS• It is costly.• Steering control may be working against

drivers who panic in emergency situations. In a panic, drivers may have the tendency to over-steer.

• It is a speed sensitive equipment.• Since the primary objective of ABS is to give

steer ability and hence the stopping distance may not necessarily decrease every time.

IMPROVEMENT IN PERFORMANCE

• Additional systems have been developed that enhance the basic benefit of the ABS.

Electronic Brake Distribution(EBD): EBD monitors the amount of brake force

required for each of the wheel and distributes it accordingly thus helping in more proper braking and extra vehicle stability.

IMPROVEMENT IN PERFORMANCE

• Traction Control System TCS uses same component as ABS but works

in the other direction. It gives wheel the necessary traction required

for movement when the whel break loose on wet surface.

CONCLUSION• ABS is a very essential safety equipment which

should be equipped in every vehicle for more safety on road.

• Also it should be kept in mind that driver should drive wisely, he should not over speed the vehicle on account of ABS as a high speed turning may roll the vehicle.

THANK YOU!