SAI TEJA15311A03D3MECHANICAL B3

What is an Anti-Lock Braking System (ABS)? Motivation for ABS Development Illustration Of ABS Slip Rate Components Of ABS Block Diagram Of an ABS Types Of ABS Advantages and Applications Disadvantages Conclusion

Presentation Outline

An anti-lock brake system is a feedback control system that modulates brake pressure in response to measured wheel deceleration, preventing the controlled wheels from becoming fully locked

What Is An ABS?

Under hard braking, an ideal braking system should:

provide the shortest stopping distances on all surfaces

maintain vehicle stability and steerability

Motivation for ABS

Anti-lock braking systems were developed to best meet these needs.

During ABS operation, the target slip rate can be from 10 to 30%.

0% slip means the wheel is rolling freely, while 100 % means the wheel is fully locked

A slip rate of 25 % means the velocity of a wheel is 25 % less than that of a freely rolling wheel at the same vehicle speed

SLIP Rate

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 AND 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. In position three, the valve releases some of the pressure from

the brakes Pump’s function is to restore pressure in the brake

lines every time the valve releases.

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.

COMPONENTS :

Illustration Of ABS

Block Diagram Of An ABS

Master Cylinder ABS ECU

Pedal

force

WHEEL

SPEED SENSO

R

Brakelines

Brake Lines

Continuous Electric Signal To ECU By Speed Sensor.

Monitorswheel

Four Channel, Four Sensor

Three Channel, Three Sensor

One Channel, One Sensor

Types OF ABS

One Channel,One Sensor

In 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.

Four Channel, Four Sensor

In 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.

Three Channel, Three Sensor

In 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 (Block Diagram)

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.

How Does It Really Work?

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. Overall it is an essential safety feature when

used wisely. It reduces stopping distance of the

vehicle(not necessarily).

ADVANTAGES OF ABS:-

ABS is effective on dry concrete roads as it reduces stopping distance of the vehicle.

.

APPLICATION OF ABS

APPLICATION OF ABS

BETTER CORNERING STEERING ABILITY

It is costly. 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.

Maintenance cost of a car equipped with ABS is more.

DISADVANTAGES OF ABS :-

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.

CONCLUSIONTHAT’S ALL OF MY PRESENTATION

Thank You