CAUVERY INSTITUTE OF TECHNOLOGY
Department of Mechanical Engineering
Technical seminar presentation
On
Anti-Lock Braking System
Submitted in partial fulfilment of the requirements for the degree of
BACHELOR OF ENGINEERING
IN
MECHANICAL ENGINEERING
Prsented by: Under the Supervision of:
Kiran Gowda HM :4CA19ME007 Prof.
Department of Mechanical Engineering
CONTENTS
Abstract
Introduction
Literature survey
Concept of ABS
Components of ABS
Working of ABS
Types of ABS
Advancements in ABS
Advantages of ABS
Disadvantages of ABS
Conclusion
Abstract
In today’s world of automobiles, safety plays a very crucial role in order to
protect the life of the driver as well as the passengers, one of the key safety
features used in automobiles is ABS. The braking system used in automobiles
is mainly used for helping the driver control the deceleration of the vehicle.
But during high speed travel the usual braking system isn’t enough in today’s
modern age as the vehicles are capable of reaching speeds beyond 60 kmph
easily and the standard barking system won’t be very helpful in stopping the
vehicle as the wheels will lock up after a certain distance and will cause the
vehicle to skid. Hence the ABS system was introduced to aid the driver in
stopping the vehicle safety.
Introduction
The modern ABS system was invented in 1971 by Mario Palazzetti (known as
'Mister ABS') in the Fiat Research Center and is now standard in almost every
car. The Anti-Lock BRAKE SYSTEM (ABS) is a mechatronic system where
mechanical, braking and hydraulic system and the electronic sensor system
work together to prevent wheel from Locking-up during heavy braking. This
allows operator to maintain steering control while stopping vehicle in shortest
distance possible. The major components are hydraulic unit, wheel speed
sensors, Electronic Control Unit (ECU) and ANTI-LOCK warning light.
LITERATURE SURVEY
1) MODELLING & DEVELOPMENT OF ANTILOCK BRAKING SYSTEM BY PARTH BHARAT
BHIVATE, NATIONAL INSTITUTE OF TECHNOLOGY ROURKELA-769008, INDIA- this
paper gives us the information related to the importance of ABS and the major
components of the ABS.
2) FOUR-WHEEL ANTI-LOCK BRAKE SYSTEM (4ABS) GROUP 35B- the paper gives us
the information regarding the major components of ABS and its functions along
with the system configuration.
3) A REVIEW PAPER ON ANTI-LOCK AND AUTOMATIC BRAKING SYSTEMS
R.Sangeethkumar1, R. Siva Shankar2 , Mohamed Marzook3 , Manova Peniel4 ,
Marshal Raj5 , Karunakaran, International Journal of Management, Technology And
Engineering- this paper gives us the information related to the advantages &
principles of ABS.
CONCEPT OF ABS
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 the vehicle has been stuck on ice and if
the wheels are spinning then the vehicle have no traction. This is
because the contact patch is sliding relative to the ice. 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. Good drivers have always pumped the brake pedal during panic
stops to avoid wheel lock up and the loss of steering control. ABS
simply gets the pumping job done much faster and in much precise
manner than the fastest human foot.
The major components of an ABS system are as follows:
1) Tandem Cylinder-The tandem master cylinder turns braking force into
hydraulic pressure, which is subsequently transferred to the wheel units through
two separate circuits.
2) Wheel sensor-An anti-lock braking sensor, often known as an ABS sensor, is a
type of tachometer that detects the rotational speed of a wheel and sends that
information to the vehicle's Engine Control Module (ECM).
3) ABS modulator- It typically comprises of an electrical engine, solenoid-
controlled ABS valves, and a base that connects the brake wires (from the master
cylinder to each brake caliper).it analyses data from the ABS sensors and regulates
braking pressure.
4) ECU-the Electronic Control Unit gathers, amplifies, and filters sensor data in
order to compute wheel rotational speed and acceleration.
5) Actuator-In an emergency, the ABS actuator is a hydraulic mechanism that
communicates with the ECU to control the brakes. The ECU analyses the rotational
speed of your wheels to the speed at which your car is moving.
6) Electronic throttle control (ETC)- is an automobile technology which
electronically "connects" the accelerator pedal to the throttle
Working of ABS
Depressing the brake pedal operates the brakes in the normal way. If the wheel sensor senses that the front right wheel is
about to lock, the computer will start up the modulator pump and close the inlet valve C4. This prevents any further pressure
from reaching the right front brake. This is known as the ‘pressure retention phase’.
If the wheel locks up, the computer will register the fact and send a signal that will open the outlet valve D4 so that pressure
is released. This will result in some rotation of the right front wheel. This is known as the ‘pressure reduction phase’. If the
sensors indicate that the wheel is accelerating, the computer will signal the outlet valve D4 to close and the inlet valve C4 to
open and further hydraulic pressure will be applied. This is known as the ‘pressure increase phase’.
These three phases of ABS braking, i.e. pressure retention, pressure release and pressure increase, will continue until the
threat of wheel lock has ceased or until the brake pedal is released.
• TYPES OF ANTILOCK BRAKE SYSTEMS
1) Four channel, four sensors ABS
This is the best method. There is speed sensor on all four wheels and a separate valve for
all the four wheels. With this set up the controller monitors each wheel individually to
make sure it is achieving maximum braking force.
2) Three channel, three sensor ABS
This system is typically seen on pick-up trucks with four wheels ABS, it has a speed sensor
and a valve for each of the front wheels, and a single valve and sensor for the rear wheels.
The sensor for the back wheel's speed is found in the back axle. This system provides
individual control of the wheels, so they can both achieve maximum braking force. The rear
wheels however are monitored together, they both have to start to lock up before the abs
will activate on the rear. With this system, it is possible that one of the rear wheels will
lock during a stop, reducing brake effectiveness.
3) One channel, one sensor ABS
This system is commonly found on pickup trucks with rear wheel abs .it has one valve
,which controls both rear wheels , and one speed sensor, located in the rear axle . This
system operates the same as the rear end of the rear channel system. The rear wheels are
monitored together and both have to start to lock up before the abs kicks in. in this system
is also possible that one of the rear wheels will lock reducing brake effectiveness.
• Advancements in ABS
A)AUTOMATIC TRACTION CONTROL (ATC)-Automatic traction control systems apply
the brakes when a drive wheel attempts to spin and lose traction. The system works best
when one drive wheel is working on a good traction surface and the other is not. The system
also works well when the vehicle is accelerating on slippery road surfaces, especially when
climbing hills. ATC is most helpful on four wheel or all wheel drive vehicles in which loss of
traction at one wheel could hamper driver control. During road operation the ATC system
uses an electronic control module to monitor the wheel speed sensors. If a wheel enters a
loss of traction situation, the module applies braking force to the wheel in trouble.
B)AUTOMATIC STABILITY CONTROL(ASC)-Like ATC, the stability control systems are
linked with the ABS. it can also be called Electronic Stability Programme (ESP). Stability control
systems momentarily apply the brakes at any one wheel to correct over steer or under steer. The control
unit receives signals from the typical sensors plus a yaw, lateral acceleration (G-force) and a steering
angle sensor. The system uses the angle of the steering wheel and the speed of the four wheels to
calculate the path chosen by the driver.
• Importance of antilock braking systems:
1.It reduces stopping distances,
2.It improves stability, and
3.It improves steer ability during braking.
• ADVANTAGES OF ABS
ABS helps you to stop sooner when you panic brake in many driving
conditions
You have the peace of mind that your car is equipped with an
advanced safety system that, at a minimum, allows you to steer
effectively even when hard braking.
It allows the driver to maintain directional stability and control over
steering during braking
It improves Safety and is a very effective system.
Automatically changes the brake fluid pressure at each wheel to
maintain optimum brake performance.
• DISADVANTAGES OF ABS
Increases the cost of the vehicle.
More expensive to repair and maintain.
Inconsistent stopping distances on various surfaces under variable conditions
Conclusion
By alternatingly increasing and decreasing hydraulic pressure in the brake line, ABS provides
rapid, automated braking in response to warnings of approaching wheel locking. According to
statistics, skidding is responsible for roughly 40% of all automobile accidents. These problems
are common in automobiles with traditional brake systems, but they can be avoided if anti-lock
brake systems are installed (ABS). If the ABS fails, the system will default to standard braking.
The ABS warning light should normally illuminate, alerting the driver to the problem.
The anti-lock braking system gives us a practical way to ensure that our new generation
vehicles become safer as they become faster and more capable. The anti-lock braking
technology ensures higher speeds with fewer dangers. The difficulties that commonly occur in
vehicles with traditional brake systems can be rectified with ABS.
• References
1)MODELLING & DEVELOPMENT OF ANTILOCK BRAKING SYSTEM.
2)A REVIEW PAPER ON ANTI-LOCK AND AUTOMATIC BRAKING SYSTEMS.
3)A Review Paper on Anti-Lock Braking System (ABS) and its Future Scope.
Thank you !
