1. A Presentation on
ANTI-LOCK BRAKING SYSTEM
An Advance Braking Technology…
Presented By:-
Shashank Shekhar,
Mechanical Engg.-3rd yr,
GIFT, BBSR.
GANDHI INSTITUTE FOR TECHNOLOGY, BHUBANES
2. INTRODUCTION TO ABS
Antilock braking systems (ABSs) are electronic
systems that monitor and control wheel slip
during vehicle braking.
ABSs can improve vehicle control during braking,
and reduce stopping distances on slippery road
surfaces by limiting wheel slip and minimizing
lockup.
Reducing wheel slip improves vehicle stability and
control during braking, since stability increases as
wheel slip decreases.
3. HISTORY OF ABS…
ABS was first developed for AirCrafts in1929 by
French Automobile & Aircraft Pioneer Gabriel
Voisin.
The German Companies BOSCH & Mercedes-Benz
pioneered the first electronic version for use on
Mercedes-Benz Cars in1936.
In 1960 A fully mechanical system used in the
Ferguson P99 racing car, the Jensen FF and the
Ford Zodiac, but saw no further use; the system
proved expensive and, in automobile use,
somewhat unreliable.
In 1975 Ford also introduced ABS on the Lincoln
Continental Mark III and the Ford LTD station
wagon, called “Sure Trak”.
4. HISTORY OF ABS Contd…
In 1978 Bosch And Mercedes-Benz Introduced
the first completely Electronic 4-Wheel Multi-
Channel ABS system in trucks and the Mercedes-
Benz S-Class.
In 1988 BMW became the world's first
motorcycle manufacturer to introduce an
electronic/hydraulic ABS system, this on
their BMW K100.
In 1992 Honda launched its first
ABS system this on the ST1100 Pan European.
5. Comparison…
Wheel lockup during braking
causes skidding which in
turn cause a loss of traction
and vehicle control.
This reduces the steering
ability to change direction.
So the car slides out of
control.
With ABS system, the
driver can brake hard, take
the evasive action and still
be in control of the vehicle
in any road condition at any
speed and under any load.
6. WORKING PRINCIPLE OF ABS
system consists of a central (ECU) Electronic
Control Unit and four wheel speed sensors
connected to each wheel and two hydraulic valves.
There is a valve in the brake line of
each brake controlled by the ABS.the valve has
three positions:
1st- The valve is open; pressure from
the master cylinder is passed right through to the
brake.
2nd- The valve blocks the line, isolating that
brake from the master cylinder.
7. III. In position three, the valve releases some
of the pressure from the brake.
When the ECU finds that any wheel is turning
faster than the other wheel, automatically brake
hydraulic pressure to the affected wheel is
increased by the ABS system so that braking
force is reapplied and the wheel slows down.
This complete process performed by the ABS
is repeated continuously throughout the drive on
mostly uneven roads and can be easily detected
by the driver of the car with the help of brake
pedal pulsation.
WORKING PRINCIPLE OF ABS Contd…
9. ABS Components
Hydraulic Components:-
1.Accumulator:-
It is used to store hydraulic fluid to maintain
high pressure.
2.Antilock hydraulic control valve assembly :-
It controls the release and application of the
brake system pressure.
3.Booster pump:-
It is used to provide pressurized hydraulic
fluid.
4.Booster/Master cylinder assembly:-
It is needed to modulate hydraulic pressure in
the wheel circuit.
10. 5.Fluid accumulator:-
It temporarily stores brake fluid that is
removed from the wheel brake.
6.Main Valve:-
This is a two position valve and is open only in
the ABS mode.
7.Modulator unit:-
It controls the flow of pressurized brake fluid
to the individual wheel circuits.
8.Solenoid valves:-
It is located in the modulator unit and are
electrically operated by signals from the control module.
11. Electrical / Electronic components
1.ABS control module:-
It monitors system operation and controls antilock function
when needed.
2.Brake pedal sensor:-
Its function is to switch on the brake lights to alert other
vehicles that the car is slowing down and/or is going to
stop.
3.Wheel speed sensor:-
These are generally used for sensing the wheel speed.
12. Types Of Anti-Lock Braking System
Four channel, four sensor ABS:- This is the best
scheme, there is speed sensor and a separate valve for
all the four wheels.
Three channel, three sensor ABS:- This scheme is
commonly found on pick up trucks with four wheels ABS,
has a speed sensor and a valve for each of the front
wheels, with one for both rear wheels.
One channel, one sensor ABS:- it has one valve ,which
controls both rear wheels , and one speed sensor,
located in the rear axle.
13. FEATURES AND BENEFITS OF ABS
Features
Benefits
Control of steering
Fail-safe
electrical/electronic
system
Traction control
ABS Indicator Lamp
Increases steering ability
and vehicle stability
during braking
If the electrical/electronic
system fails, the ABS is
shut off
It is an optional feature
that controls excessive
wheel spin during
acceleration
Informs the driver or
technician that an ABS
fault has occured
14. ADVANTAGES…
It allows the driver to maintain directional
stability and control over steering during braking.
Safe and effective.
Automatically changes the brake fluid pressure at
each wheel to maintain optimum brake
performance.
ABS absorbs the unwanted turbulence shock
waves and modulates the pulses thus permitting
the wheel to continue turning.
DISADVANTAGES…
It is very costly.
Maintenance cost of a car equipped with ABS is
more.
15. CONCLUSION
Statistics show that approximately 40 % of
automobile accidents are due to skidding.
These problems commonly occur on vehicle with
conventional brake system which can be avoided
by adding devices called ABS.
If there is an ABS failure, the system will
revert to normal brake operation. Normally the
ABS warning light will turn on and let the driver
know there is a fault.
