energy harvesting from highway traffic through compressed air

COLLEGE OF EME, NUST

Energy Harvesting from Highway Traffic through Compressed

Air

NS Muhammad Azam Raza

NS Nabeel Wahab Khan

NS H. M. Waqas Saleem

NS Muhammad Amir Idrees

Project Supervisors

Col. Dr. Syed Waheed Ul Haq

Col. Dr. Mazhar Iqbal

Asst. Prof. Rehan Ahmed Khan

Department of Mechanical Engineering

2

Energy Harvesting from Highway Traffic through Compressed Air

By

NS Muhammad Azam Raza

NS Nabeel Wahab Khan

NS H. M. Waqas Saleem

NS Muhammad Amir Idrees

DE-31 (DME)

Submitted to the Department of Mechanical Engineering

In partial fulfillment of the requirements for the degree of

Bachelor of Engineering in Mechanical

----------------------------------

Project Supervisors


Col. Dr. Mazhar Iqbal

Asst. Prof. Rehan Ahmed Khan


College of Electrical and Mechanical Engineering,

NUST.

----------------------------------

Head of Department



College of Electrical and Mechanical Engineering,

NUST.

July, 2013

College of Electrical and Mechanical Engineering

National University of Sciences and Technology

3

DECLARATION

We hereby declare that no portion of the work referred to in this Project Thesis has been

submitted in support of an application for another degree or qualification of this of any

other university or other institute of learning. If any act of plagiarism found, we are fully

responsible for every disciplinary action taken against us depending upon the seriousness

of the proven offence, even the cancellation of our degree.

COPYRIGHT STATEMENT

Copyright in text of this thesis rests with the student author. Copies (by any

process) either in full, or of extracts, may be made only in accordance with

instructions given by the author and lodged in the Library of NUST College of

E&ME. Details may be obtained by the Librarian. This page must form part of

any such copies made. Further copies (by any process) of copies made in

accordance with such instructions may not be made without the permission (in

writing) of the author.

The ownership of any intellectual property rights which may be described in this

thesis is vested in NUST College of E&ME, subject to any prior agreement to the

contrary, and may not be made available for use by third parties without the

written permission of the College of E&ME, which will prescribe the terms and

conditions of any such agreement.

Further information on the conditions under which disclosures and exploitation

may take place is available from the Library of NUST College of E&ME,

Rawalpindi.

4

ACKNOWLEDGEMENT

First of all, we are eternally grateful to Allah Almighty who blessed us with wisdom and

courage to achieve what we had promised.

Secondly, we are thankful to our project supervisor Col. Dr. Syed Waheed Ul Haq who

gave us the initial idea about producing compressed air from speed breaker and without

his motivation and persistent help, we could not do this project. Thirdly we would like to

thank Sir Raja Amir Azeem for his suggestions and continuous guidance throughout our

project.

Next, we would like to thank the college authorities for providing us with required pre-

requisite. In the Last but not the least we would like to express our acknowledgement for

our parents who educated us enough well and their prayers remained with us at all the

times.

5

ABSTRACT

The natural resources in our country are decaying day by day. These energy crises

includes short fall of thousands of megawatts of electricity, the increasing prices of fuels

like gasoline, CNG etc. It seems that for foreseeable future, these crises would persist. So

to contribute to this national cause, we had been assigned a project to work on renewable

energy.

The aim of our project was to design an efficient energy harvester which will act like a

speed breaker and which will utilize the highway traffic for its working. An energy

harvester is a device that actually converts the vehicles mechanical energy into usable

electrical energy.

The working principle of our project is that when a vehicle will pass over it, it will move

down, by doing so, the air will be compressed by pistons. And this air will be used for

driving engine or generator directly for producing electricity. Different software's have

been used for its modeling, analysis and parametric studies i.e. Pro/E, ANSYS

Workbench 14.0 and matlab.

6

TABLE OF CONTENTS

Declaration and Copyright Certificate.....3

Acknowledgements.........4

Abstract...5

Table of Contents. .6

List of Figures.....10

CHAPTER 01

INTRODUCTION

1.1. Energy Harvesting Types.13

1.1.1. Overview........13

1.1.2. Solar Energy..13

1.1.3. Wind Energy..14

1.1.4. Bio-Mass.........15

1.1.5. Speed Breaker as an energy harvester16

1.2. Aim of project17

1.3. Motivation......18

CHAPTER 02

SPEED BREAKERS GENERAL OVERVIEW

2.1. General Overview..20

2.2. Types of Speed Breakers...21

2.2.1. Normal Speed Breaker/Hump.....21

2.2.2. Speed Cushions.....22

2.2.3. Speed Tables..22

7

2.3. Selection of Speed Breaker.......23

2.3.1. Selection Criteria..........23

2.3.2. Requirements of Speed Breaker..24

2.4. Conclusion..24

CHAPTER 03

MATERIAL SELECTION

3.1. Introduction...25

3.1.1. Aluminum...25

3.1.2. Mild Steel....27

3.1.3. Cast Iron.....28

3.2. Conclusion........................................................................................29

CHAPTER 04

DESIGNING OF MECHANICAL COMPONENTS

4.1. Springs..30

4.1.1. Constraints....30

4.1.2. Material..31

4.1.3. Assumptions......31

4.1.4. Springs selection Criteria.32

4.1.5. Design No. 1...32

4.1.6. Design No. 2...34

4.1.7. Design No. 3...34

4.1.8. Inspection Report..36

4.2. Bolts...37

4.2.1. Assumptions...37

4.2.2. Lower Base Bolts Calculations.....38

4.2.3. Upper Plate Bolts Calculations.....41

4.2.4. Inspection43

4.3. Pressure Cylinder..43

4.3.1. Software Designing (MD Solids)...43

4.3.2. Mohr Circle.48

8

CHAPTER 05

SOFTWARE MODELING, ANALYSIS AND FABRICATION

5.1. Components Used in our Modeling49

5.1.1. Upper Part49

5.1.2. Pistons.........51

5.1.3. Lower Part.........53

5.1.4. Full Assembly....55

5.2. Analysis....56

5.2.1. Upper Plate56

5.2.1.1. Design No.1..56

5.2.1.2. Design No. 2.....58

5.2.1.3. Design No. 3.....61

5.2.2. Lower Plate...63

5.2.2.1. Design No.1......63

5.2.2.2. Design No. 2.66

5.2.2.3. Design No.3..68

5.3. Fabrication......70

CHAPTER 06

COMPRESSOR DESIGNING

6.1. Assumptions....73

6.2. Calculations.....73

6.3. Conclusions..74

CHAPTER 07

CONTROL SYSTEM DESIGNING

7.1. Designing......75

CHAPTER 08

SELECTION OF ENGINE

8.1. Wankel engine.....79

8.1.1. Advantages...79

8.1.2. Disadvantages...80

8.2. Two Stroke Engine.....80

8.3. Four Stroke Piston Engine.81

9

8.4. Selection...81

8.5. Basic Functions of compressed air engine81

8.6. Modifications Required..82

8.6.1. Stroke-1.82

8.6.2. Stroke-2.82

8.6.3. Timing82

8.6.4. Camshaft Design...82

8.6.5. Design Concept of Camshaft...83

8.6.6. Analysis of Camshaft...83

8.6.6.1. Constraints and Pressure Application........83

8.6.7. Modal Analysis ....84

8.6.8. Static Analysis...85

8.7. Fabrication of Camshaft.87

CHAPTER 09

COMPRESSED AIR APPLICATIONS

9.1. Applications...89

CHAPTER 10

CONCLUSIONS AND RECOMMENDATIONS

10.1. Conclusions..90

10.2. Recommendations...90

REFERANCES.91

10

List of figures

Fig: 1.1 Common working cycle of a solar panel...14

Fig: 1.2 Windmill turbine along with the main components15

Fig: 1.3 Anaerobic compositing..15

Fig: 1.4 No of vehicles per 100,000 people....17

Fig: 1.5 Protest against the load shedding in Lahore...........18

Fig: 1.6 Protest against load shedding in Peshawar..18

Fig: 2.1 Common speed breaker.....20

Fig: 2.2 Speed Bump across the width of the road...21

Fig: 2.3 Speed Cushions across the width of the road..22

Fig: 2.4 Speed Tables......23

Fig: 3.1 Silver Grey Metallic Aluminum...25

Fig: 3.2 Mild Steel Sheets...27

Fig: 3.3 Cast iron sheets.....28

Fig: 4.1 Suspension Springs...30

Fig: 4.2 Storage cylinder....43

Fig: 5.1 Front View....49

Fig: 5.2 Side View..50

Fig: 5.3 Top View..50

Fig: 5.4 Isometric View of upper part......51

Fig: 5.5 Isometric View of piston 51

Fig: 5.6 Front View of piston ..52

Fig: 5.7 Top view of piston ..52

Fig: 5.8 Upper Assembly...53

Fig: 5.9 Front view of lower part .53

Fig: 5.10 Right view of lower part54

Fig: 5.11 Top view of lower part .....54

Fig: 5.12 Isometric view of lower part .55

11

Fig: 5.13 Full assembly ...55

Fig: 5.14 Upper with all loading conditions...56

Fig: 5.15 Von-mises stress of design no.1.........57

Fig: 5.16 Shear stress of design no.1..57

Fig: 5.17 Total Deformation of design no.1..58

Fig: 5.18 Von mises stress of design no.2 59

Fig: 5.19 Max. Principal stress of design no.2..59

Fig: 5.20 Shear stress of design no.2 60

Fig: 5.21 Total Deformation of design no.2 .60

Fig: 5.22 Von mises stress of design no.3 61

Fig: 5.23 Stress Intensity of design no.3 ..62

Fig: 5.24 Total Deformation of design no.3 .62

Fig: 5.25 Lower Part with loading conditions.......63

Fig: 5.26 Von Mises stress of lower plate design no.1 .64

Fig: 5.27 Max. Principal stress of lower plate design no.164

Fig: 5.28 Stress Intensity of lower plate design no.1.65

Fig: 5.29 Total Deformation of lower plate design no.1....65

Fig: 5.30 Von Mises Stress of lower plate design no.2 .66

Fig: 5.31 Max. Principal Stress of lower plate design no.2...66

Fig: 5.32 Max. Shear stress of lower plate design no.2.............67

Fig: 5.33 Total Deformation of lower plate design no.267

Fig: 5.34 Von Mises Stress of lower plate design no.3..68

Fig: 5.35 Max. Principal Stress of lower plate design no.3....68

Fig: 5.36 Max. Shear stress of lower plate design no.3..69

Fig: 5.37 Total Deformation of lower plate design no.369

Fig: 5.38 Assembling of spring...70

Fig: 5.39 Punching of holes for outlets ............71

Fig: 5.40 Lower Base...71

Fig: 5.41 Full Assembly..72

Fig: 5.42 Pressure Cylinder.72

Fig. 7.1: Speed Breaker model full assembly....75

Fig. 7.2: Free body diagram76

Fig. 7.3: Step Response Plots....78

Fig: 8.1: Wankel engine....................79

12

Fig: 8.2: Two Stroke engine80

Fig: 8.3: Four Stroke Engine...81

Fig: 8.4: Cam Shaft original design.82

Fig: 8.5: Pro/E modeling of cam shaft....83

Fig: 8.6: Constraints and Pressure application...83

Fig: 8.7: Modal analysis of cam shaft.....84

Fig: 8.8: Max. Displacement..84

Fig: 8.9: Deformed Shape..85

Fig: 8.10: Max. Displacement of static analysis........85

Fig: 8.11: Max. Principal stress.86

Fig: 8.12: Max. Shear stress..86

Fig: 8.13: Von Mises stress...86

Fig: 8.14: Wooden model.....87

Fig: 8.15: Comparison between original and modified designs87

Fig: 8.16: Full assembled two stroke compressed air engine88

13

Chapter 1

INTRODUCTION

With the gradual increase in the prices of fossil fuels and other traditional sources of

energy, there rises a great need for alternate sources in order to meet the energy needs for

a country. And also these fossil fuels are depleting day by day. The over view of the

energy consumption in year 2004 shows that if these resources are being consumed at the

current rates, then by 2020, more than 80% of the entire available energy resources will

be consumed particularly oil and natural gas. The combustion products produced from the

petrol, diesel etc. has caused serious global problems, which includes the ozone layer

depletion (which stops the suns UV rays from coming to earth), greenhouse effect,

environmental pollution and acid rains. These are posing great danger to our environment.

1.1. Energy Harvesting Types

1.1.1. Overview

With the increase in energy demands, the use of alternative energy resources has been

increased since past few years. These alternative sources of energy are limitless that one

can imagine which includes solar energy, Bio-mass, Hydel energy, Nuclear energy and

Wind energy etc. One of these alternative sources of energy harvesting is via speed

breakers.

1.1.2. Solar Energy

Solar energy is the energy coming from the sun in the form of light and heat. It is

harnessed using specially designed photovoltaic cells called solar cells. These

photovoltaic cells are made of semiconductor materials like those found in computers

chips. When a beam of sun light hits the surface of the cell, it stimulates the electrons to

loose from their atoms. As the electrons starts flowing through the cells, they become the

14

cause of electricity generation. These solar cells are placed in particular direction in order

to get maximum energy from the sun. Now a days, the large scale concentrating parabolic

collectors are being used for harnessing this energy. It is actually producing less than

1/10th

of the 1% of total energy demand.

The above figure shows the cycle of working of a common solar panel. As we know that

sun is imparting its energy almost everywhere on earth. And the solar systems designed

for harnessing this energy have appeared to be successful up to some extent. There is a

need to store this energy via storage batteries to provide energy during night and cloudy

days.

1.1.3. Wind Energy

Wind energy is the energy harnessed from wind. It is harnessed using wind turbines, wind

mills and wind pumps. The large wind turbines are employed in open area where the

speed of wind is more than enough to drive wind energy harvesting systems. Wind mill

pumps are used to pump water from underground. Here in this case pistons are used to

pump water from underground.

Wind turbines have large specially designed impellers on which when high speed air

strikes, become the cause of rotation of the impeller. This impeller is connected to the

shaft of the generator via gears which eventually drive the generator for producing

electricity. Figure 1.2 shows the parts of a wind mill turbine and also the direction of air

Figure 1.1: Common working cycle of a solar panel

15

on the blades. Here in this figure, we can see that the blades are connected to the

generator via shaft and gears assembly.

1.1.4. Bio-Mass

Bio-Mass is an organic matter from wood, dead bodies and animal waste. It is also one of

the form of energy used as a source of heat for domestic purposes. The municipal waste,

manure, and agricultural by products are also included in the category of bio-mass which

can be converted into valuable fuels for vehicles and industrial applications. It is actually

a universal source of energy which can be converted in almost every form of energy as

liquid and natural gas, electricity and process heat etc. Different technologies have been

used for bio-mass conversion.

Direct Combustion

Anaerobic Digestion

Figure 1.2: Windmill turbine along with the main components

Figure 1.3: Anaerobic Compositing

16

Thermo Chemical Conversion

Enzymatic Fermentation

1.1.5. Speed Breaker as an energy harvester

We are all familiar with the term speed breaker. Speed breaker is actually used to slow

down the speed of the vehicle on crowded roads and to decrease the road accidents.

People usually do not like these speed breakers. And also they become the cause of noise

pollution and environmental pollution as the traffic passes over with low speed gear,

means more fuel per mile. But we can make use of these speed breakers to get energy. On

road when vehicles passes over the speed breakers, these vehicles losses enormous

amount of energy. We can make these speed breakers as an efficient energy harvester.

According to the statistics provided by Additional Director General, Excise & Taxation,

Lahore, Punjab, the rate of growth of traffic on roads has been increased during past ten

years. This rate of growth is increasing day by day. This increase in the number of traffic

along with the increase in number of speed breaker stimulates to make use of these speed

breakers. The following table 1.1 shows the increase in number of vehicles from 2002 to

2011. [1]

Table 1.1: No. of registered vehicles in Punjab

17

1.2. Aim of project

We can make use of these speed breakers by manufacturing a mechanical system that can

work like speed breaker as well as provide usable energy too. In this report, there is a

practical fabrication of this system which can be used for both purposes. This speed

breaker will provide us compressed air which can be used to generate electricity via

engine, turbine etc. T-59 tank pistons have been used for compressing the air.

Design of speed breaker as a source of alternate energy:

Uses road traffic for its working

No need of any external source of energy for working

Air to be compressed is atmospheric air

Is compact

Is less costly to be fabricated and to be maintained

Figure 1.4: Statistical data provided by Government of Punjab, no. of vehicles per 100,000 people

18

1.3. Motivation

The main thing from which we get motivation for this idea of producing compressed air

from speed breaker is the current situation of Pakistan. Load shedding of electricity and

Sui-gas has crossed all the limits. Almost every day, we see there is a protest going on

against load shedding of electricity, or increase in the prices of petroleum etc. There are

some pictures shown below, from where it can easily be seen.

Figure 1.5: Protest against the load shedding in Lahore [2]

Figure 1.6: Protest against load shedding in Peshawar [3]

These pictures depict the current situation of Pakistan. Our police are also unable to

control this situation because this is a fact and what can they do? They are also under the

same situation as the other public. Nobody is free enough to go outside for nothing, but

just for protest. But these problems initiate an individual to do these kinds of thing.

Everyone is tight due to this. There should be some permanent solution to these problems.

Our countrys economy has severely affected from this. Because most of the industries

are totally dependent on these two sources particularly. Most of the investors have moved

19

their business from our country, multinationals are moving from this country. Pakistan is

passing through the worst era of history. In order to save our country, we have to put an

effort to contribute to decrease the bad situation of Pakistan. Although this contribution is

very small that has a minor effect on the energy crises but if it worked then it can be

applied at major level to produce usable energy.

We are not alone in the world who is encountering the energy problem; many other

developing countries of the world are also facing these problems. But they have found

some means to cater for these problems. We have got this enthusiasm from other

developing nation of the world. We would be proud to do something for our country and

our people.

20

Chapter 2

SPEED BREAKERS GENERAL OVERVIEW

2.1. General Overview

Speed breaker is generally a device used to reduce the speed of the vehicle in order to

stop the road accidents. In different countries it is known with different names. For

example, in Jamaica, it is known as a sleeping policeman/a kipping cop. In British

accent, it is known as speed hump/road hump. In New Zealand accent, it is known as,

a judder bar. And Pakistani and Indian usually use to say it as Speed jump. It usually

ranges in heights between almost 3in to 4 across the whole width of the road. They are

made of different materials like recycled plastic, asphalt, metal and rubber etc.

The use of these speed breakers has been increased in the world and they can be found at

those places where there is a need to slow down the vehicles speed. The speed limit for

these speed breakers is almost 11 m/sec (40 km/h). Although they are effective in

reducing the speed of the vehicle. But they are the cause of noise pollution and also

become the cause of vehicle damage if a vehicle passes over it with high speed. Figure

2.1 shows the common speed breaker.

Figure 2.1: Common speed breaker

21

2.2. Types of Speed Breakers

Speed breakers are classified in different ways. The types of speed breakers include the

following:

1- Normal Speed Breaker

2- Speed Cushions

3- Speed Tables

2.2.1. Normal Speed Breaker/Hump

It is the type of the speed breaker which is actually provided throughout the full width of

the road. The height of these speed breakers ranges between 3 in to 4 in. This type of

speed breakers are used on highly populated roads where there are greater chances of road

accidents. They usually have pavement like marks in order to increase the visibility for

motorists. They are not used for big roads or emergency routes. They are generally made

of rubber, asphalt type materials. Their tops are rounded and they are smaller in length

than the speed tables. Here the figure 2.2 shows the speed hump across the width of the

road.

Figure 2.2: Speed Bump across the width of the road

22

2.2.2. Speed Cushions

These type of speed breakers are smaller in sizes. These type of speed bumps do not

cover the whole width of the road. Instead these are in two cushions on place with smaller

spaces between them, both having height of almost 3 in and having width of almost 67 in

across the width of the road. They are actually provided for emergency services or where

the bus services operate. They are designed in such a way that the greater size vehicles

can straddle the cushion without slowing down the speed. But the smaller vehicles have

to pass over these because these vehicles cannot straddle the cushion. Figure 2.shows the

speed cushions attached to the road with spaces between them.

2.2.3. Speed Tables

This type of speed breakers are longer speed bumps along with a small flat segment in the

center. They are enough long to cover the whole wheel base of a vehicle. Their design is

such that they can allow a vehicle to pass over without being slow.as with the normal

speed breakers or speed cushions. As they slow the vehicle less than the other types, they

Figure 2.3: Speed Cushions across the width of the road

23

are used on high dense roads with some particular speed limits. Typical speed limits used

for these types of speed breakers ranges from 20 mi/hr. to 30 mi/hr. Figure 2.4 shows the

speed tables.

2.3. Selection of Speed Breaker

2.3.1. Selection Criteria

There are many selection criteria available that can be used. But the primary criteria that

can be used are actually a type of forces applied on the speed breaker and stiffness of the

suspension springs, heavy duty and cost. The operating conditions for this vary over a

wide range as it is installed in an open environment and hence the broad spectrum of

seeks is applied for their designing and performance. All these implications must be

considered when assessing the unit that to be used. While selection of speed breaker,

there are following points that must be kept in mind:

Materials to be used, of overall speed breaker

Operating forces and temperature ranges

Types of loads acting

Types of springs to be used

Types of pistons

Figure 2.4: Speed Tables

24

Maintenance, cleaning, inspection, repair possibilities and extension

Economically feasible

Fabrication Techniques to be used

Applications

2.3.2. Requirements of Speed Breaker

There are some requirement that speed breaker has to fulfill that includes:

High pressure compressed air generation capability

High life expectancy and reliably

Safe operation so that it might not damage the lower side of the vehicle

High quality product

Low residual stresses be introduced in the design

Material compatibility with the outside environmental conditions

Easy to be installed and convenient in size

Maintenance and service should be easy.

Easy to be manufactured

It should be of low cost

2.4. Conclusion

We are not discussing the actual speed breaker or their working, nor types and uses.

These things can be found on web. Because here in our case the geometry of speed

breaker that we are using is important due to the availably of space.

Our main requirement is that our speed breaker should be compact in size and light in

weight if possible. Moreover, the cost of this whole assembly should be less. After

studying the mentioned types of speed breaker, we come to a conclusion that we cannot

use any of speed breaker from here. So we have designed our own speed breaker which

resembles a little bit with the speed tables. After doing some necessary mathematical

calculations and experiments we can say that it can fulfill our requirements.

25

Chapter 3

MATERIAL SELECTION

3.1. Introduction

There are many materials available that can be used. These materials include aluminum,

Mild steel or Low carbon steel, and Cast iron. Lets first discuss these materials and their

properties.

3.1.1. Aluminum

Aluminum is a ductile material and is found in the boron group in the periodic table. Its

color is silvery white. The symbol for this metal used is Al; having atomic number 13.

This metal is not actually soluble in water. It is found in the Earth crust in abundance and

3rd most abundant metal. Earths total weight comprises of almost 8% of this elements

solid surface. It is one of the reactive elements in the nature.

It has very good resistance to corrosion capabilities. Its alloys are mostly used in

aerospace and other transportation and building areas. As it is reactive in nature this can

be used as a catalyst in the chemical mixtures. Also it is used in explosives as ammonium

nitrate to extend the blast power.

Figure 3.1: Silver Grey Metallic Aluminum

26

Table 3.1: General properties of Aluminum

Table 3.2: Miscellaneous properties

27

It is a very soft material, durable, light in weight, and malleable with different

appearances range from silver to dull greyish. It cannot be soluble in alcoholic liquids.

The yielding of this metal in pure form ranges from 7MPa to 11MPa. While, its alloys

have yield strengths in range from 200 to 600Mpa. As its surface consists of very thin

layer of aluminum oxide, its corrosion resistance is very high.

In powdered form, it does not leave its silvery color. Its atoms are arranged in a face

centered cubic structure. [4]

3.1.2. Mild Steel

It is most common form of carbon steel having 0.16 to 0.29 % of carbon contents. It do

not come in the category of brittle or ductile. Its yield strength is 248 MPa and ultimate

tensile strength of 841 MPa.

It is relatively cheap and malleable as compared to the other materials. If it is passed

through carburizing process its hardness can be increased. It is used as a structural steel

when it is needed in larger amounts. Its density is approximately 7.85 g/cubic centimeter

and the modulus of elasticity is almost 210 GPa. It usually suffers from yield run out.

Because, it has only one yield point. But other materials have two yield points. The first

yield point in those materials is always higher than the next one and it drops dramatically.

[5]

Figure 3.2: Mild Steel Sheets

28

3.1.3. Cast Iron

When we talk about cast iron then we are actually talking about the Gray iron. It

identifies actually the ferrous group. Its alloys can be identified by the color of the

fractured surface. Grey cast iron is usually named because of its greyish fractured surface.

Its alloys consist of Carbon and silicon elements. It comprises of 2.1-4% of cast iron by

percent weight. And also they contains very handsome amount of silicon normally range

from 1-3% by percent weight. Its melting temperature ranges from 1150 degree C to

1200 degree C. which is almost 300 degree C lower than the pure irons melting point.

It comes in the category of brittle excluding malleable cast iron. As it has low melting

point, good resistance to deformation and wear, good machinability and cast ability, it has

become one of the most usable engineering material having wide range of different

applications. It is resistant to rusting and destruction.

Figure 3.3: Cast iron sheets

Its main component is silicon which makes it grey cast iron. It has many useful

properties. When it is solidified, it expands as the graphite precipitates. This results in the

sharp casting of material. It has high thermal conductivity because of graphite present in

it. It has capability to damp the mechanical vibrations. [6]

29

Table 3.3: Comparative properties of different types of Cast iron

3.2. Conclusion

Aluminum is softer material and also very expensive so this is not suitable for our case.

Because in our case, the material should be harder so that it can bear the load of almost

500 to 600kg and also reversal loadings.

Cast iron is brittle material as compared to mild steel and aluminum. It cannot be bended

as easily as other materials do. Because it contains high carbon contents. Which make it

very strong and brittle.

Mild steel has all properties which we needed. It can easily be bended and easy to work.

It is also not very costly and easily available. So, we have selected this material for our

project.

30

Chapter 4

DESIGNING OF MECHANICAL COMPONENTS

In our project, the components to be designed include the following:

1. Springs

2. Bolts

3. Pressure cylinder

4.1. Springs

Spring is the main component of our project. It is serving two purposes. One, this is

supporting the upper part and the second, when a load is applied on the upper part, the

upper plate and piston assembly moves down, it is then used to restore the upper

assembly to its original position. Different springs were designed and best design was

selected on the basis of our loading conditions and other general requirements.

Figure 4.1: Suspension Springs

4.1.1. Constraints

In our project, there are two constraints on the basis of which we have selected our

springs.

1. Rod on which spring is wounded

31

2. Height

Here material can also be our constraint because of its availability. We have used Chrome

silicon steel for our spring designing.

These constraints are applied to all the spring designs.

4.1.2. Material

4.1.3. Assumptions

1. Isotropic properties.

2. Select the weakest point that shows the strength of material.

3. There is no buckling.

4. Stress concentration is assumed negligible.

5. Temperature effects are negligible.

6. Gravity is constant (9.8

2).

7. No humidity.

8. Perfect lubrication.

9. No crack is induced.

10. The machine element is mechanically balanced and no vibration will be induced.

Therefore, there is no additional fatigue load acting upon the part.

11. Nested round wire due to space limit.

12. No localized yielding induced.

13. Short peening is engineering decision.

14. Stiffness is consistent according to Energy Theory.

15. Set removal is zero for fatigue.

16. The induced stresses of wire bending are normal to shear loading so we ignore it

due to hot working.

32

17. Buckling is not possible as spring is guarded by cylinders and rods.

These assumptions are applied to all the spring designs.

4.1.4. Springs selection Criteria

The spring selection criteria is based on the following:

4.1.5. Design No. 1

The maximum weight on the springs is 600 kg.

( ) ( )

Over a rod

The Bergstrasser Factor is

( ) ( )

( )

33

( )

( )

( )

( )

( )

As this design is fulfilling our requirement, it can be our suitable design. But for the time

being, we cannot take it as our final design. First we will discuss other designs with

varied diameter.

34

4.1.6. Design No. 2

The maximum weight on the springs is also same i.e. 600 kg.

( ) ( )

Over a rod


( ) ( )

( )

4.1.7. Design No. 3

The max. Weight in this case will also be same.

( ) ( )

35

Over a rod


( ) ( )

( )

( )

( )

36

( )

( )

( )

As height, is our one of the constraint so we cannot go beyond 381 mm where solid

length of 13 mm diameter spring is 339.46mm.

Which is far less than we need so this is also not feasible. So we are left with spring

design # 1 having wire diameter of 10 mm.

4.1.8. Inspection Report

The maximum weight on the springs is 600 kg.

( ) ( )

Over a rod


( ) ( )

( )

37

Our design depends on the availability of the desired spring from the market because

manufacturing of our own spring is very costly. From the spring designs above, it is clear

that spring design # 1 is the best option but it is not available from market so we looked

for the spring having a wire diameter nearly equal to 10 mm so we got the spring having

wire diameter of 9.525 mm which is having a factor of safety nearly equal to that of 10

mm wire diameter spring.

4.2. Bolts

Bolt is the next member after spring which is bearing load. Now, there are some design

consideration for bolts.

4.2.1. Assumptions

1. The stress concentration effects are neglected.

2. The bolt is not tighten much otherwise the washer can crack.

3. During tightening, assume not all load eventually drops at the nut head.

4. Inertial effects are neglected.

5. Nuts used are new and never used before.

6. Isotropic properties.

7. Temperature effects are negligible.

8. Gravity is constant (9.81

2).

9. No humidity.

38

10. It is mechanically balanced so there is no vibration in it. Therefore there is no

additional fatigue load acting upon the part.

These assumptions will be used for both upper and lower part of the assembly.

4.2.2. Lower Base Bolts Calculations

The bolts used are of steel.

Table 4.1: Standards for Bolts

39

The next size nearest to this calculation is 32mm = 3.2 cm for the bolt.

(

)

( )2

Where Tensile-stress area

Length of threaded portion in grip

Major diameter area of fastener

Length of unthreaded portion in grip

Where is the estimated effective stiffness of the bolt or cap screw in the clamped zone

or area.

[ ]

Where

C= Fraction of load applied P on bolt

40

Table 4.2: SAE Standards for steel bolts

SAE Grad 1

Assuming a factor of safety of 5 for 3 bolts

41

Rearranging above equation for P, we get

( )

Where

P= External tensile load

Factor of safety = n =5

No. of bolts used = N = 3

So, using values we get,

So the allowable stress would be:

Which is lower than .

Now as we can see from the above calculations that the maximum allowable strength is

lower that the proof strength of the bolt material, so on the basis of these calculations we

can say that our bolt is safe.

4.2.3. Upper Plate Bolts Calculations

( )

42

Table 4.3: Standards for Bolt Threads

43

4.2.4. Inspection

The available bolts in market are of IBI standards. We have to use bolts of this standard.

There is a minor difference in the dimensions of the bolts used in the calculations. But all

the calculation are done for the SAE standard bolts.

4.3. Pressure Cylinder

Pressure cylinder is used to store the compressed air from the compressor. When have to

check the safety of our cylinder which would be holding the pressurized air so that we can

confidently store the compressed air.

Figure 4.2: Storage cylinder

The stress calculation has been done using MD SOLIDS software. There is report

generated from this software.

4.3.1. Software Designing (MD Solids)

The hoop stress is computed from the equation:

.

The axial stress is computed from equation

44

Normal stresses in the cylinder wall:

( )( )

The axial stress parallel to the longitudinal axis of the closed cylinder is

( )( )

The hoop and axial stresses are the in-plane principal stresses for the cylinder. The third

principal stress acts in a radial direction. On the other side of the cylinder, the (gage)

pressure is zero.

Consequently, the radial stresses in our case will be:

On the inner surface, the radial stresses will be

As the pressure pushes the inside surface. The magnitude of the radial stresses is much

smaller than the in-plane stresses, and it is often ignored. If the radial stress is considered,

a state of tri-axial stress exists on the inner surface of the cylinder,

, is the third principal stress. This non-zero principal stress affects the

magnitude of the absolute maximum shear stress.

Shear stresses in the cylinder wall:

The absolute max. Shear stress on the outside surface of a closed cylindrical pressure

vessel occurs in an out-of-plane direction.

45

This shear stress is given by the equation,

( )( )

The maximum shear stress in the plane of the cylinder wall (in-plane shear stress) is given

by

( )( )

On the inside surface of a closed cylindrical pressure vessel, the absolute maximum shear

stress must account for the radial stress created directly by the pressure. The most positive

principal stress is the hoop stress,

And, the most negative principal stress is the radial stress,

Therefore, the absolute maximum shear stress on the inside surface of the cylinder will

be given by

( )

[ ( )]

Strains in the cylinder wall:

The strains in the cylinder wall due to internal pressure pose an interesting situation.

When we design a pressure vessel, we usually speak in terms of gage pressure rather than

absolute pressure. On the outside of the cylinder, the gage pressure is zero. Since there is

no pressure acting in the radial direction, the normal stress in the radial direction on the

outside surface of the cylinder wall is zero. The stresses on the outside surface of the

cylinder act entirely in the plane of the wall (that is, in the circumferential and

longitudinal directions); therefore, the wall is in a state of biaxial stress. We must use

Hooke's Law for biaxial stress to compute the normal strains.

46

Using

The circumferential strain is given by the equation:

(

) ( )

(

) ( )

And the strain in the axial direction is given by:

(

) ( )

(

) ( )

The strain in the radial direction (caused by the Poisson effect) is given by the equation:

(

) ( )

(

) ( )

The internal pressure creates an equal compression stress in the radial direction on the

inner surface of the cylinder (i.e., ).

Since there are normal stresses in three direction on the inside surface of the cylinder

(longitudinal, hoop, and radial directions), the wall is under the state of tri-axial stress.

We must use Hooke's Law for tri-axial stress to compute the normal strains.

Using

, the circumferential strain is given by the equation as:

(

) [ ( )]

(

) [ ( )]

47

And, the strain in the axial direction is given by the equation:

(

) [ ( )]

(

) [ ( )]

.

The strain in the radial direction (caused by the Poisson effect) is given by

(

) [ ( )]

(

) [ ( )]

.

Note that the difference between the strains on the outer and inner surfaces is relatively

small, and this difference gets smaller as the ratio of inside radius to wall thickness (r/t)

gets larger. Because of this, the effect of pressure on the inside surface of the cylinder is

sometimes neglected when computing strains in the cylinder.

Stresses on a weld:

The normal and shear stresses acting perpendicular to the specified welded joint (that is,

in the n-direction) are given as:

And

(CW on the n face), respectively.

The normal and shear stresses acting parallel to the specified welded joint (i.e., in the t-

direction) are given by:

And

Respectively.

48

4.3.2. Mohr Circle

49

Chapter 5

SOFTWARE MODELING, ANALYSIS AND FABRICATION

After completing the designing of theoretical part, there comes the software modeling

part. As it is necessary to investigate our model in some software like Pro/E, ANSYS etc.

because these software include all the factors which we cannot include in our manual

designing like temperature effects, different material properties, different physical

properties etc. This is also because now a days, industries also use different designing

software in order to get more reliable results.

The software used for modeling of our project is Pro/E wildfire 5.0. And the analysis of it

has been done on ANSYS workbench 14.0 with module static structural.

5.1. Components Used in our Modeling

The components include in our modeling are given under.

5.1.1. Upper Part

The upper part has been modeled in such a way that upon loading it will move down and

due to spring action in opposite direction, it will move back to its original position.

Keeping these things in mind, we designed it in Pro/E according to our assumptions.

Figure 5.1: Front View

50

Figure 5.2: Side View

Figure 5.3: Top View

51

Figure 5.4: Isometric View

These are the different view of upper part modeling.

5.1.2. Pistons

The modeling of pistons has also been done using Pro/E.

Figure 5.5: Isometric View

52

Figure 5.6: Front View

Figure 5.7: Top view

53

Figure 5.8: Upper Assembly

5.1.3. Lower Part

The part is the main base of the project on which upper assembly is supported by the

springs. We have modeled it also on Pro/E.

Figure 5.9: Front view

54

Figure 5.10: Right view

Figure 5.11: Top view

55

Figure 5.12: Isometric view

5.1.4. Full Assembly

Both the lower and upper parts are assembled using Pro/E assembly module.

Figure 5.13: Full assembly

In this assembly, the pistons are connected through a rigid joint. The pistons are adjusted

in this assembly using the cylinder command in the sleeves such that the piston can move

56

in the sleeves and compressed air can be produced. Springs are connected using

mechanisms in Pro/E assembly.

5.2. Analysis

Now, here comes the part of analysis.

Here in our case, as we cannot do the manual calculations for the upper and lower plates

so we have to do this using some designing software. We have used ANSYS workbench

14.0. There are three designs each for both the plates.

In our case, as we have selected mild steel. We can do designing on the basis of this.

Another thing is that we can use the greater length. But we cannot use the greater length

as our design is already enough large in size, so with the increase in the size, then more

space will be required for its installation. Last thing, which is now left behind is the

thickness of the both plates. All these analysis have been done on the worst case

scenarios.

5.2.1.Upper Plate

5.2.1.1. Design No.1

Thickness of the upper plate = 2mm

After applying loadings,

Figure 5.14: Upper with all loading conditions

57

After running analysis, we got results as shown below:

Figure 5.15: Von-mises stress

Figure 5.16: Shear stress

58

Figure 5.17: Total Deformation

Factor of Safety:

The factor of safety can be found by the given formula:

( )

As the factor of this design is very low which can be used for our case because of heavy

duty work. And the also the deformation are greater in this case.

5.2.1.2. Design No. 2

Here in this case, the loading conditions would be same.

After doing analysis, we got results as

59

Figure 5.18: Von mises stress

Figure 5.19: Max. Principal stress

60

Figure 5.20: Shear stress


61

( )

Now this factor of safety is reasonable for our case as there are reversal loadings present

in it. But first we have to examine that the next design is more feasible for our project or

this one.

5.2.1.3. Design No. 3

Also here in this case, the loading conditions are same.

Figure 5.22: Von mises stress

62

Figure 5.23: Stress Intensity


63

( )

The results shows that this is also suitable design for our case. But as we know that the

higher the factor of safety, the higher the price of material. So keeping in all aspects, we

come to a conclusion that the best choice is the second design.

5.2.2.Lower Plate


Thickness of lower plate= 5mm

After applying loadings:

Figure 5.25: Lower Part with loading conditions

The analysis of the above plate shows the following results:

64

Figure 5.26: Von Mises stress


65

Figure 5.28: Stress Intensity


Although we are applying load on this plate which cannot be reached up to this extent.

But still this factor of safety is very low we cannot chose this for our project.

66

5.2.2.2. Design No. 2

Thickness of the plate = 5mm

Analysis of this plate shows the following results:

Figure 5.30: Von Mises Stress

Figure 5.31: Max. Principal Stress

67

Figure 5.32: Max. Shear stress


This can be suitable for our final design but we have to first examine the next design than

on the basis of both these results we can conclude our final result.

68


Thickness of the plate= 7mm Analysis of this design shows the following results:

Figure 5.34: Von Mises Stress

Figure 5.35: Max. Principal Stress

69



This can be more feasible design for our project but we cannot take this because if we

take this thickness, our project would be not be economical.

So, our suitable design would be 5mm.

70

5.3. Fabrication

Different techniques has been used for the fabrication of our project. The material used

here was already been decided in the past chapters. These techniques includes the

following:

Bending

Welding

Sand Casting

Machining

Polishing and Finishing

Hydraulic Pressing

Figure 5.38: Assembling of spring

71

Figure 5.39: Punching of holes for outlets

Figure 5.40: Lower Base

72

Figure 5.41: Full Assembly

Figure 5.42: Pressure Cylinder

73

Chapter 6

COMPRESSOR DESIGNING

In our case the pistons which are in sleeves and are well insulated are acting as a

compressor. The inlet to the compressor is the hole as in the case of two stroke engines.

The initial pressure of the air is atmospheric pressure. When piston passes through the

inlet hole it compresses the air to certain high pressure which then opens the check valve

and compressed air moves to the storage cylinder. The calculation of the discharge

pressure from the cylinder is calculated as follows.

6.1. Assumptions

1. This is isothermal process. There is no change of temperature as we are not

dealing with higher pressure.

2. Friction is neglected

3. Atmospheric pressure is 1 bar.

4. There isnt any loss of pressure

6.2. Calculations

Given data:

Solution:

First we have to find the compression ratio from the formula given below

Displaced volume can be calculated as:

Putting values

The clearance volume can be calculated as:

74

(

)

So

Now putting values of and we get

Where

6.3. Conclusions

75

Chapter 7

CONTROL SYSTEM DESIGNING

7.1. Designing

The main parts included in our system for control system designing are:

Springs

Pistons

The springs has been discussed in detail in past chapters. So here we will discuss the

Piston which is actually acting as a damper in our case.

Damper is the part of suspension system and it functions as it has liquid in it and as we

know that liquids are incompressible moreover, dampers are used in combination with

springs and as the vehicle passes through rough roads, damper makes the motion of

spring smooth as it has liquid so liquid takes the force and keeps the vehicles smooth and

comfortable for the passengers. Here in our project as sir is being compressed in the

cylinders with the help of pistons. When force is applied on the ramp it moves down and

compresses the air but as air is compressed and a pressure is developed inside and that air

cant be further compressed so it will oppose the motion of the ramp and thus acting like

a damper.

Figure 7.1: Speed Breaker model full assembly

As we see in the above figure that our four springs are in parallel with each other and our

4 dampers are also in parallel to each other so we can think of our project having one

spring and one damper and we can model it with one degree of freedom. The below

diagram shows the one degree of freedom diagram

76

Figure 7.2: Free body Diagram

Now we are going to drive its transfer function and state space model

Using laplace transform

( )

( )

( )

Now for state space model we use the initial differential equation

Replacing

[

] [

] [

]

Equations can be written as

Comparing Equations

77

Now putting values

( )

( )

This is our required transfer function. Now using Matlab we have found the different

types of response plots.

Matlab Code:

For simple case:

>> m=30;

k=15500;

c=4309.87;

s = tf('s');

P = m/(s^2 + (c/m)*s + (k/m));

step(P)

stepinfo(P)

ans =

RiseTime: 0.5953

78

SettlingTime: 1.0671

SettlingMin: 0.0523

SettlingMax: 0.0581

Overshoot: 0

Undershoot: 0

Peak: 0.0581

PeakTime: 2.7996

Figure 7.3: Step Response Plots

79

Chapter 8

SELECTION OF ENGINE

We have different engine which we can modify according to our design. But first of all

we have to investigate that which engine will fulfill our requirement.

8.1. Wankel engine

Wankel engine is actually a variable volume progressive cavity device. The whole space

is divided into three housings, each repeating the same cycle. Now as we know that the

rotor rotates and arbitrarily revolves thus compressing and expanding the combustion

chamber. There is one combustion stroke for two revolutions of crank shaft for a 4-stroke

piston engine while wankel engine is capable of generating a combustion stroke per each

drive shaft revolution which means one power stroke per each revolution and three power

strokes per revolutions therefore the power generated by wankel engine is much greater

as compared to 4-stroke piston engine having similar engine properties. This engine has a

higher power output. It is also because of the smoothness in the circular motion which

eliminates dangerous vibrations that can occur in the reciprocating engine due to of their

working.

Figure 8.1: Wankel engine

8.1.1. ADVATAGES

80

As the rotor is directly connected to the output shaft in the Wankel engine thus there is no

need of connecting rods, a crankshaft and crankshaft balancing weights that is why

Wankel engine is lighter than that of reciprocating engine of similar power output.

Vibrations produced by Wankel engine is less as discussed above so it results in smoother

power flow.

8.1.2. Disadvantages

The overall sealing of Wankel engine is worse even piston rings are not perfectly sealed

and allow for expansion. This is the main factor for decreasing the efficiency of Wankel

engine and constraining its use in the automobile industry.

8.2. Two Stroke Engine

The desire to have one revolution of crank shaft to produce work compared to two

revolutions of crank shaft to produce work in a 4-stroke piston engine has led to the

invention of 2-stroke engine.

Figure 8.2: Two Stroke engine

There are no piston valves in the 2-stroke engine but there are inlet and exhaust ports due

to which the suction and exhaust strokes are eliminated. The spark plug starts ignition

when the compression stroke is near to its completion. When 80% of the power stroke is

complete, the exhaust port is opened slightly which gives a slight way to exhaust gases

but as piston moves further downward the inlet port is also uncovered and fresh fuel

moves in expelling the remained exhaust gases into the atmosphere. For a 2-storke

81

engine, the specific fuel consumption is more than a 4-stroke engine which increases the

cost of its operation.

8.3. Four Stroke Piston Engine

There are four strokes comprising of intake stroke, compression stroke, power stroke and

exhaust stroke. During the inlet stroke the piston moves downward in order to get a fresh

charge of fuel and then compressing it to a certain level. Combustion is initiated by a

spark plug and thus power is produced, as the piston reaches the bottom dead center the

exhaust valve is opened and exhaust gases move out during the exhaust stroke of the

piston.

Figure 8.3: Four Stroke Engine

8.4. Selection

Using air as a fuel to run engine requires perfect insulation. As we all are aware of the

compressors in which a slight leakage can ruin all the efforts. First choice was Wankel

engine but we were constrained to look for other engine because of its least availability in

Pakistan market. We looked at 2-stroke engine but in this case, for an engine to work on

compressed air we have to give it a mean effective pressure on piston head, our inlet and

power stroke cant be overlapped which is necessary so it was also rejected. Next option

considered was a 4-stroke engine which met our criteria of overlapping the inlet and

power stroke so we decided to convert this 4-stroke piston engine to compressed air

engine.

We selected a C-70 engine and we will move on to understand its operations and we will

derive a system to convert it to compressed air engine.

8.5. Basic Functions of compressed air engine

82

As we know there will be only two strokes required for a compressed air engine to work.

Air with certain mean effective pressure will push the piston down thus giving a power

stroke and as the piston moves up, the exhaust valve will have to be opened so that the air

can get out and piston can travel in upward motion without any hurdle. The next condition

is that the intake valve must be closed while piston is coming up so that there can be

minimum forces on the piston head.

8.6. Modifications Required

It is required to convert a 4-stroke engine to 2-stroke engine as we require only 2 strokes.

Let us define these two strokes first.

8.6.1. Stroke-1

In the first stroke, intake valve will open and compressed air will push the piston down

hence the intake stroke will also act like the power stroke.

8.6.2. Stroke-2

In this stroke, exhaust valve will open and the air which is still at higher pressure than

ambient will move out.

8.6.3. Timing

For the compressed air engine, it is obvious that both the valves must be open twice for

each revolution of crank shaft as compared to a conventional 4-stroke engine in which

valve open once every two revolutions. This obviously telling us that there is a need to

change the design of camshaft.

8.6.4. Camshaft Design

The movement of valves is being controlled by camshaft, the lobes on the camshaft are

designed to open the valves accordingly. If the profile of camshaft is changed it will

change the timing of the valve motion. Camshaft of the C-70 is shown in the diagram

below.

Figure 8.4: Cam Shaft original design

83

For two revolutions of crankshaft, camshaft will move only one revolution and valves will

open only once. Now, we want to open the valves twice during one revolution of camshaft

so we have to make mirror of each lobe at 180 degree to existing lobe means now we have

four lobes.

8.6.5. Design Concept of Camshaft

Cam shaft has been designed so that it opens twice both the inlet and exhaust valve twice

during one revolution. The proposed design is as follows:

Figure 8.5: Pro/E modeling of cam shaft

8.6.6. Analysis of Camshaft

We did analysis of the camshaft on PRO-E wildfire 5. The steps are as follows

8.6.6.1. Constraints and Pressure Application

Figure 8.6: Constraints and Pressure application

84

As in our case the camshaft only rotates in one plane while its translation in any direction

is restricted so we gave the camshaft the displacement constraint along X Y Z directions.

While it is constrained to rotate in XY plane. The conditions are shown in the figure

above. As we know that the only component upon which force will act are the lobes of

camshaft so we only applied pressure on the lobes. We searched for the pressure which is

acting on the camshaft lobes and applied it. After that we selected the material which is

steel in our case.

After the application of constraints, pressure and material we are now able to run the

analysis. The results are as follows.

8.6.7. Modal Analysis

Figure 8.7: Modal analysis of cam shaft

The aim of this analysis is to see maximum displacement of the camshaft. After selecting

the modal analysis we ran the analysis to see the results.

Figure 8.8: Max. Displacement

85

This is the displacement for the combined mode and its value is 2.66 and these will be

balanced by rocker reaction so our model is safe and reliable.

The deformed shape is as follows

Figure 8.9: Deformed Shape

8.6.8. Static Analysis

The maximum displacement in this case is

Figure 8.10: Max. Displacement of static analysis

86



Figure 8.13: Von Mises stress

87

After applying the von misses stress criteria and compared it with the yield strength of the

steel the factor of safety found to be 56.88. These analysis shows that the camshaft is safe

so we can use it in our engine.

8.7. Fabrication of Cam shaft

The processes used for fabrication of our cam shaft are as follows:

Wood working

Sand Casting

Machining

Polishing and finishing

Figure 8.14: Wooden model

Figure 8.15: Comparison between original and modified designs

88

Figure 8.16: Full assembled two stroke compressed air engine

89

Chapter 9

COMPRESSED AIR APPLICATIONS

In everyday life, compressed air can be used in countless different ways. Compressed air

is widely used in industry because of its safety and reliability. Most of the companies use

compressed air at some stages of their operations. In modern industries, the

manufacturing processes often utilizes compressed air. Equipment in automotive working

shops, presses, dry clean stores depends upon reliable compressed air supply. Road

construction companies also use compressed air to power their tools. It is also used in

blowers, pneumatic tools and spraying guns. Some of these applications are mentioned

here as:.

9.1. Applications

Vehicle services

Foods and beverages:

Power generation

In Plastics

In wood

In Electronics

In metals

90

Chapter 10

CONCLUSIONS AND RECOMMENDATIONS

10.1. Conclusions

Our project is although a small but not the least effort towards the harvesting of energy.

Now this is the suitable time because our country is facing huge energy crises.

Our speed breaker is producing compressed air having pressure of almost 5 to 6 bar. We

have also modified Honda CD 70 bike engine as an application of compressed air. This

engine requires compressed air having pressure of almost 3 bar. Our goal was to achieve

compressed air having a pressure of 7-8 bar which we have nearly achieved. As this was a

new idea, so achieving such pressure is above our expectations. The whole assembly is

simple and easy to install. The selection of right material for the upper and lower plates

was a great deal for us. Similarly the suspension springs were not that easy to select. Thus

this project was a great increase in our practical and theoretical knowledge.

10.2. Recommendations

We have used mild steel for our project but it is too heavy and there is a risk of

rust and corrosion so we recommend that composite materials should be used

instead as it can provide same strength, it would be non-corrosive and it will be

lighter than mild steel.

We have used 4 pistons for compressing air and these pistons are connected to

upper sheet through connecting rods which are acting as point loads. In order to

avoid these point loadings we recommend the connection between the upper plate

and pistons via truss structure so that the whole weight can be distributed evenly

in the truss members.

As we are using a single system to produce compressed air, we recommend that a

number of such systems should be placed in series in such a way that the output of

one system is the input of other system and so on. In this way we will get more

pressurized compressed air for our utility.

91

REFERENCES

1- http://adeelmohammad.weebly.com/1/archives/04-2013/1.html accessed on 02-07-

2013

2- http://piaf.pk/photogallary.html accessed on 02-07-2013

3-http://pukhtunkhwatimes.blogspot.com/2009/07/protest-against-loadshedding-

in.html accessed on 02-07-2013

4- http://en.wikipedia.org/wiki/Aluminium accessed on 03-07-2013

5- http://en.wikipedia.org/wiki/Mild_steel#Mild_steel accessed on 03-07-2013

6- http://en.wikipedia.org/wiki/Cast_iron accessed on 03-07-2013

7- Tasfia Rahman- Design of Efficient Energy Harvester from Ambient Vibration- Thesis

Work, April 2012

8- Andrea Pirisi, Francesco Grimaccia, Marco Mussetta, and Riccardo E. Zich- Novel

Speed Bumps Design and Optimization for Vehicles Energy Recovery in Smart Cities-

14 November 2012

9- Aswathaman. V- Energy Speed Breaker is Now a Source of Power- 2010 International

Conference on Biology, Environment and Chemsitry, IPCBEE vol. 1 (2011) IACSIT

Press, Singapore

10-Ashok Kumar Sharma, Omkar Trivedi, Umesh Amberiya, Vikas Sharma-

Development of Speed Breaker device for generation of compressed air on highways in

remote areas- International Journal of Recent Reseach and Review, VOL 1, March 2012

energy harvesting from highway traffic through compressed air

Documents

library of nust college

college authorities

project thesis

nust energy harvesting

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