1. The Project work submitted to
Rajiv Gandhi Proudyogiki Vishwavidyalaya,
Bhopal
Towards partial fulfillment of
The Degree of
Bachelor of Engineering
In
Mechanical Engineering
Submitted to: - Submitted by:-
Mr. Akhare Bhushan Neeraj ku.
shukla(0818me091062)
Jitendra singh
hada(0818me091044)
Nitesh rathor(0818me091064)
Jitendra singh (0818me091046)
Mechanical Engineering Department
INDORE INSTITUTE OF SCIENCE AND TECHNOLOGY
INDORE (M.P.)
2011-2012
2. 2011-2012
RECOMMENDATION
The project report entitled ,”Value Analysis of Anti Lock Braking System”,submitted
to the Rajiv Ghandhi Proudyogiki Viswavidhyalaya,Bhopal, M.P by Mr. Neeraj
kumar shukla ,Mr. Jitendra singh hada,Mr.nitesh rather and Mr.Jitendra singh
during the academic year 2012, As a partial fulfilment for the award of degree of he
bachelor of engineering in Mechanical Engineering, is a record of their own work
carried out by the team under our direct supervision, in the department of M.E., IIST
INDORE. The work contained in the report is a satisfactory account of their project
work and is recommended for the award of the degree.
Guide Head
Mr. Bhusan Akhare Mr. Rajeev
vijaywargiya
(Asst. proff. M.E. Dept.) (HOD, ME
Dept.)
3. INDORE INSTITUTE OF SCIENCE AND TECHNOLOGY
2011-2012
CERTIFICATE
This is to certify that the project work entitled “VALUE ANALYSIS OF ANTI LOCK BRAKING
SYSTEM” submitted by........................., student of Third year B.E. (Mechanical Engineering)
in the year 2012-2013 of Computer Engineering Department of this institute, is a satisfactory
account of his work based on syllabus which is approved for the award of degree of Bachelor
of Engineering in Mechanical Engineering.
Internal Examiner External
Examiner
Date: Date:
4. ACKNOWLEDGEMENT
After the completion of this Project work, words are not enough to express my feelings about all those
who helped me to reach my goal; feeling above this is my indebtedness to The Almighty for providing me
this moment in life.
In this project we received constant support from our esteemed HOD Mr. ...........I am heartily indebted to
Mr..................... for his constant support and guidance. Without his guidance and scholarly suggestion an
urge to bring out the best would not have been possible. I hope to propagate his scientific, industrial and
professional fervors to the best of my abilities. His clear view and knowledge provided help during every
phase of Project Development. His perpetual motivation, patience and excellent expertise in discussion
during progress of the project work have benefited me to an extent, which is beyond expression. His depth
and breadth of knowledge of Computer Engineering field made me realize that theoretical knowledge
always helps to develop efficient operational software, which is a blend of all core subjects of the field. He
was major support to me throughout my project, being available with his odd ideas, inspiration and
encouragement. It is a through his masterful guidance that I have been able to complete my Project.
I am also thankful to all the Teaching and Non-Teaching staff and Lab Assistants from Computer
Engineering Department and the Friends and people who helped me directly or indirectly for the completion
of this project, with success.
The successful completion of a Project is generally not an individual effort. It is an outcome of the
cumulative effort of a number of persons, each having their own importance to the objective. This section is
a vote of thanks and gratitude towards all those persons who have directly or indirectly contributed in their
own special way towards the completion of this project.
Last but not the least, I would like to express my deep appreciation for my family members for providing
their kind support and encouragement without which the completion of this project would be a dream.
Thanks to GOD for the unwavering support.
5. ABSTRACT
Design and Fabrication of Anti-Lock Braking System “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.”
Anti-Lock Braking Systems (ABS) are designed to maintain driver control and stability
of the car during emergency braking. Locked wheels will slow a car down but will
not provide steering ability. ABS allows maximum braking to be applied while
retaining the ability to
'steer out of trouble„. The operation of ABS can slightly reduce stopping distance in
some cases like on wet road surfaces, but it can increase the stopping distance in
others,
as may be the case in deep snow or gravel. An ABS system monitors four wheel
speed sensors to evaluate wheel slippage. Slip can be determined by calculating the
ratio of wheel speed to vehicle speed, which is continuously calculated from the four
individual wheel speeds. During a braking event, the function of the control system is
to maintain maximum possible wheel grip on the road - without the wheel locking - by
adjusting the hydraulic fluid pressure to each brake by way of electronically controlled
solenoid valves. While ABS offers improved vehicle control in some circumstances, it
can also present disadvantages including increased braking distance on slippery
surfaces such as ice, packed snow, gravel, steel plates and bridges, or anything
other than dry pavement. ABS has also been demonstrated to create a false sense of
security in drivers, who may drive more aggressively as a result.
Since initial widespread use in production cars, anti-lock braking systems have evolved
considerably. Recent versions not only prevent wheel lock under braking, but also
electronically control the front-to-rear brake bias. This function, depending on its
specific capabilities and implementation, is known as electronic brakeforce distribution
(EBD), traction control system, emergency brake assist, or electronic stability control.
6. INTRODUCTION
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 (split
or low coefficient of friction) road surfaces by limiting wheel slip and
minimizing lockup. Rolling wheels have much more traction than locked
wheels. Reducing wheel slip improves vehicle stability and control during
braking, since stability increases as wheel slip decreases.
ABSs can be applied to nearly all types of
vehicles and can be successfully integrated into hydraulic and air brake
systems.
7. Fig:-1-Anti lock braking system
WORKING PRINCIPLE OF ABS
An ABS consists of several key components: electronic control unit (ECU), wheel
speed sensors, modulator valves, and exciter rings. Here’s how these components work
together:-
1. Wheel speed sensors constantly monitor and send electrical pulses to the ECU at a
rate proportional to the wheel speed.
2. When the pulse rates indicate impending wheel lockup, the ECU signals the
modulator valve(s) to reduce and/or hold the brake application pressure to the
wheel(s) in question.
3. The ECU then adjusts pressure, seeking one which gives maximum braking without
risking wheel lockup.
4. When the ECU acts to modulate the brake pressure, it will also (on most vehicles)
turn off the retarder (if so equipped) until the risk of lockup is over.
8. 5. The ECU continually checks itself for proper operation. If it detects a
malfunction/failure in the electrical/electronic system, it will shut down that part
of the ABS affected by the problem—or the entire ABS—depending upon the
system and the problem. When this happens, the ABS malfunction lamp lights. An
ABS adjusts brake pressure much faster and more accurately than can drivers. It’s
faster because:
• electronic controls are very fast and
• ABS modulator valves are physically closer to the brakes than is the driver’s foot
brake valve.
It is more effective, too, because an ABS can tailor the brake pressure to each
wheel or set of wheels to provide maximum braking/stability. Some vehicles also use a
traction control system in conjunction with the ABS. Traction control helps the ABS
improve vehicle traction by minimizing wheel slip on the drive axle during
acceleration. If a wheel on the drive axle starts to slip, the traction control system
automatically brakes the wheel slightly, transferring engine torque to the wheels with
better traction. If all the drive wheels start to slip, the traction control system may also
reduce engine power.
Traction control systems are referred to by several different names, depending on the
manufacturer. These include:
• Automatic Traction Control (ATC)
• Traction Control (TC)
15. COMPONENTS OF ABS
Electronic Control Unit (ECU)
Modulator Valves
Wheel Speed Sensors
pump
ELECTRONIC CONTROL UNIT :- The ECU processes all ABS information and signal
functions. It receives and interprets voltage pulses generated by the sensor pickup as
the exciter teeth pass by, and uses this information to determine:
• Impending wheel lock-up.
• when / how to activate the ABS modulator valves.
The ECU connects to the following ABS components: wheel speed
sensors, ABS modulator valves, power source, ground, warning lamps.
MODULATOR VALVE :- ABS modulator valves regulate the air pressure to the
brakes during ABS action. When not receiving commands from the ECU, the
modulator valve allows air to flow freely and has no effect on the brake pressure. The
ECU commands the modulator valve to either:
• change the air pressure to the brake chamber, or
• hold the existing pressure.
However, it cannot automatically apply the brakes, or Increase the brake application
pressure above the level applied by the driver.
16. WHEEL SPEED SENSORS:- The anti-lock braking system needs some way of
knowing when a wheel is about to lock up. The speed sensors, which are located at
each wheel, or in some cases in the differential, provide this information.
Fig:-wheel speed sensor
17. PUMP :- Since the valve is able to release pressure from the brakes, there has to
be some way to put that pressure back. That is what the pump does; when a valve
reduces the pressure in a line, the pump is there to get the pressure back up.
Fig:- Working of pump
18. DIFFERENT TYPES OF ABS
One-channel, one-sensor 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 a three-channel system. The rear wheels
are monitored together and they both have to start to lock up before the ABS
kicks in. In this system it is also possible that one of the rear wheels will lock,
reducing brake effectiveness. This system is also easy to identify, as there are
no individual speed sensors for any of the wheels.
Four-channel, four-sensor ABS :- There is a speed sensor on all four
wheels and a separate valve for all four wheels. With this setup, the controller
monitors each wheel individually to make sure it is achieving maximum
braking force.
Three-channel, three-sensor ABS :- it has a speed sensor and a valve for
each of the front wheels, with one valve and one sensor for both rear wheels.
The speed sensor for the rear wheels is located in the rear axle. This system
provides individual control of the front 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.
Three-channel, four-sensor ABS:-There is a speed sensor on all four
wheels and a separate valve for each of the front wheels, but only one
valve for both of the rear wheels.
19. VALUE ANALYSIS
WHAT IS VALUE ANALYSIS ?
Value analysis is a systematic effort to improve upon cost and/or performance of
products (services), either purchased or produced. It examines the materials,
processes, information systems, and the flow of materials involved. Value Analysis
efforts began in earnest during WW II. GE, concerned with the difficulties in
obtaining critical listed materails to produce war material, assigned an engineer,
Lawrence D Miles to the Purchasing department. His mission was to find adequate
material and component substitutes for critical listed material to manufacture needed
war equipment. In his search, Miles found that each material has unique properties
that could enhance the product if the design was modified to take advantage of those
properties.
Miles discovered that he could meet or improve product performance and reduce its
production cost by understanding and addressing the intended function of the product.
His method was - Blast (dissecting products to discern key competitive advantages),
Create (detailed analysis of the disassembled products, identifying those functions of
concern and soliciting ideas for improving), Refine (selecting the most value adding,
cost-effective ideas and preparing a business case for the implementation of the
proposals) - the VA Tear Down Analysis. The key element in Miles' work is that he
separated Function (what it must do) from the characteristics of the design (how it
does it). Value = Function/Cost (esteem value - want, exchange value - worth, utility
value - need).
US Navy adopted this in 1945 as Value Engineering. The Defense Department
described Value Engineering as a "before the fact" activity applying the value
methodology during the product design phase and Value Analysis as "after the fact"
activity, practicing the value process following design release, during the production
of the product.
20. Why is it important?
Implemented diligently, value analysis can result in: -
1. reduced material use and cost
2. reduced distribution costs
3. reduced waste
4. improved profit margins
5. increased customer satisfaction
6. increased employee morale.
When to use it?
Value analysis should be part of a continuous improvement effort.
How to use it?
Start by asking these questions:-
1. What is the function of the item?
2. Is the function necessary?
3. Can a lower cost standard part that serves the purpose be identified?
4. To achieve a lower price, can the item be simplified, or its specifications
relaxed?
5. Can the item be designed so it can be produced more efficiently or more
quickly?
6. Can features that the customer values highly be added to the item?
21. VALUE ANALUYSIS OF ABS
Material selection
An automotive brake disc or rotor is a device for slowly or stopping the motion of the
wheel. While it runs at a certain speed. The widely used brake rotor material is cast
iron which consumes much fuel due to high specific gravity the material selection for
the application of brake disc system emphasising on the substitution of this cast iron
by any other light weight material such as cost per unit property and digital logic
methods material performance requirement were analyzed and alternative solutions
were evaluated among cast iron ,aluminium alloy, titanium alloy ceramic and
composite mechanical property including compressive strength , wear resistance
,thermal conductivity ,specific gravity as well as cost were used as a key parameter in
material strength stages. The analysis led to all metal matrix composite as a most
appropriate material for brake system.
Design
An antilock brake system is designed for a specific vehicle application. A truck which
does not pull a trailer, like a cement mixer, would have a slightly different ABS than a
truck tractor which pulls one or more trailers. Likewise, an antilock brake system for a
trailer would have a different design.
ABS for automobiles may be even more specific and may be designed for a particular
Regardless of manufacturer or the type of vehicle, all antilock brake systems operate
in a similar manner. Wheel speed sensors are placed on each wheel that is to be
controlled. Each speed sensor usually has a toothed wheel that rotates at the same
speed as the vehicle wheel or axle. If the brakes are applied and one or more of the
monitored wheels suddenly begins to reduce speed at a higher rate than the others, the
controller activates the antilock system.
Since ABS components must fit and function along with existing vehicle components
on each model, the design and manufacturing process of a new antilock brake system
22. is carried out in partnership between the automobile manufacturer and the ABS
supplier.
Raw Materials
The toothed wheel or gear in the speed sensor is made of soft iron, usually cast. Iron
is chosen because of its high magnetic permeability and low magnetic reluctance.
Magnetic reluctance is roughly equivalent to electrical resistance, and sometimes the
toothed wheel is called the reluctor. The function of the toothed wheel is to allow the
permanent magnet's field to easily pass through each tooth to cause a momentary
concentration of field strength which induces a current in the pick-up coil. The pick-
up coil has a permanent magnet in the core, wrapped with a coil of copper wire.
The controller usually employs transistors known as hot-side drivers which control the
power side of the circuit rather than the ground side. These transistors produce more
heat than is usual in an electronic circuit. Rather than being placed in a plastic or
23. stamped steel housing, they are attached to a cast aluminum housing with a finned
heat sink to dissipate the heat.
The hydraulic brake pressure solenoids used in automobiles have a standard
construction of copper coil elements with steel valves and bodies. They are housed in
the same casing as the brake system master cylinder which is usually cast from
aluminum.
The electrical wiring is copper, often with cross-linked polyethylene insulation. To
prevent radio frequency interference (RFI), in which high-power radio signals might
be received through the wiring and cause the system to activate, all wiring is either
shielded or the wires are run as twisted pairs to cancel out the effects of radio waves.
Connectors are plastic with internal copper contacts.
The Manufacturing Process
The manufacturing process for antilock brake systems consists of manufacturing the
component parts and then installing those parts on the vehicle. The parts are built in
one plant, then packaged and shipped to a vehicle assembly plant for installation. This
is a typical process for an automobile antilock brake system.
Making the master brake cylinder
The master cylinder, including the base for the solenoid body, is cast as a
single unit. The seating and sealing surfaces are machined smooth and the
connection ports are threaded.
The individual primary and secondary pistons, solenoid coils, reservoir caps
and seals, pressure accumulator, and any metering and proportioning valves
are installed. The solenoid body has a cover which attaches to the master
cylinder with four or more screws and is sealed with a gasket.
Making the wheel speed sensors
The toothed wheel is cast from iron. Minor machining may be required at the
mounting points.
The pick-up coils are wound around the permanent magnet core in a
machine called a coil winder. The entire assembly is encased, or potted, in
plastic resin with an electrical connector attached.
24. Making the controller
The electronic controller components are soldered to a printed circuit board.
The board is connected inside a protective housing and mounted to the cast
aluminium heat sink base. External electrical connections are provided for the
input wiring from each speed sensor and the out-put wiring to the solenoids
in the master brake cylinder.
Installing the ABS
In the automobile assembly plant, the steel tubing brake lines are installed in
the framework of the body. They run from the partition between the engine
compartment and the occupant compartment, called the firewall, to the
vicinity of each wheel. The electrical wires for the ABS are also run from the
vicinity of each wheel to the controller location and from the controller to the
firewall.
The brake master cylinder is bolted to the firewall in the engine
compartment near the brake pedal. The brake lines are attached to the
appropriate ports on the solenoid body, and the electrical wires are
connected.
The toothed sensor wheels are pressed onto the outer constant velocity
joints or the ends of the axle spindles so that they ride just inside the wheels.
Once the axles are attached to the frame, the brake lines are attached and
the pick-up coils are installed so that the end of the coils are close to the
toothed wheels. The pick-up coils are then electrically connected to the wires
to the controller.
The controller is installed either under the instrument panel or in the vehicle's
trunk. The electrical connections are made, including the power connection
from the vehicle battery through the fuse-box.
Quality Control
The idea of an electronic system being able to take over the operation of a vehicle's
brakes is disturbing to some people. For this reason, the operation of the system is
25. thoroughly tested beforehand, and the quality of the installation is constantly
reviewed.
In addition, all antilock brake systems are designed to be fail-safe—that is, any failure
of any component will cause the system to fail in such a manner as to still allow the
overall safe operation of the brakes.
26. CALCULATION
ANALYSIS OF FORCES
Forces Acting on a brake Application
P = Force applied at the end of lever.
R= Normal force pressing the brake block on the wheel.
F= Tangential braking force or frictional force acting at the contact surface of the
block.
T= Braking torque
r = Radius of the wheel.
ø = Angle of contact surface of the block.
µ = Coefficient of friction.
1. F= (µ x R)
2. T= Fx r = (µ x R) x r
Case 1.
When the line of action of (F) passes through fulcrum of the lever.
27. Then taking moment about the fulcrum ‘O’, We have
Rx X = P x L or R= (P x L) / X
T= µ x Rx r = (µ x P x L x r) / X
28. Case 2.
When the line of action of (Ft) passes through a distance (‘a’) below the fulcrum ‘O’,
then taking moment about the fulcrum ‘O’
(Rn x X) + (Fx a) = P x L
µ Or R= (P x L) / (X+x a)
T= µ x Rx r = (µ x P x L x r) / (X +µ x a)
29. Case 3.
When line of action of (F) passes through a distance ‘a’ above the fulcrum ‘O’, then
taking moments about O, we have
Rn x X = (P x L) + (Fx a) = (P x L) + (µ x Rn x a)
Rn= (P x L) / (X - µ x a)
T= µ x Rn x r = (µ x P x L x r) / (X - µ x a)
30. ENERGY ABSORBED BY THE BRAKE
Case 1.
When the motion of the body is pure translation.
Change in kinetic energy of vehicle of mass (m) moving with velocity (V1) is reduced
to velocity (V2),
E= ½ x m x [(V)– (V)]
If the vehicle is stopped after applying brake, then E= ½ x m x (V).
Case 2.
When the motion of the body is pure rotation.
When the body of mass moment of inertia ‘I’ is rotating about an axis with angular
velocity ‘v ’ is reduced to ‘ ’rad/s after applying the brake. Therefore change in
kinetic energy E= I = ½ x L x [()–()]
If the rotating body is stopped after applying
E= I = ½ x L x ()
Case 3.
When the motion of the body is both translation and
Rotation.
.
Therefore , Total kinetic energy to be absorbed by the brake,
E=E+E
N1= Speed of the brake drum before brake is applied
N2= Speed of the brake drum after brake is applied
N = Mean speed of brake drum = (N1+N2)/2
Total energy absorbed by the brake must be equal to the workdone by frictional force,
therefore E = (Fx px d x N x t)
Or F= E / (px d x N x t)
31. CASE STUDY
Q:-To stop a vehicle of 1200kg in a distance of 50m which is moving down the hill
at a slope of 1:5 at 72km/h. How much would be the average braking torque
required.
SOLUTION:-We have,
M =1200kg; slope = 1:5; v=72km/h=20m/s; h=50m
Average braking torque to be applied to stop the vehicle We know that kinetic energy
of the vehicle
E=( ½ x m x V)= ½ x 1200 x (20)= 240000N-m
The Potential energy of the vehicle,
FP = (m x g x h) x slope = (1200 x 9.81 x 50) x 1/5 = 117720N-m
Total energy of the vehicle or energy absorbed by the brake,
E = E+ E= 240000 + 117720 = 357720N-m
Tangential braking force to stop the vehicle in a 50m distance,
F= 357720 / 50 = 7154.4N
Average braking torque to be applied to stop the vehicle,
T= F x r = 7154.4 x 0.3 = 2146.32N-m
STRESS ANALYSIS
Rectangular Projected Area Brake shoe
Width of Brake Shoe, W= 155mm
Length of Brake shoe, L = 250mm
Projected Bearing Area of brake Shoe,
A = 38750mm2
F= 7154.4N
Stress on brake shoe, Sb = F/ A = 7154.4 / 38750
= 0.1846N/mm2
