A PROJECT REPORT ON

APPLICATION OF KERS IN BICYCLE: AN INVESTIGATION

in partial fulfillment for the award of the degree

of

BACHELOR OF ENGINEERING

in

MECHANICAL ENGINEERING

Submitted by

PARTHA PRATIM BORAH (M-27/13)

KAUSHIK KALITA (M-40/13)

SABIR HUSSAIN CHOUDHURY (M-48/13)

SULTAN AHMED CHOWDHURY (M-49/13)

Under the guidance of

MR.RANBIR KALITA

(GUEST FACULTY)

JORHAT ENGINEERING COLLEGE,

JORHAT

DIBRUGARH UNIVERSITY::DIBRUGARH

2018

CANDIDATES’ DECLARATION

We hereby declare that the work which is being presented in this project entitled, "APPLICATION OF KERS IN A BYCYCLE : AN INVESTIGATION" is an authentic

record of our own work carried out during the period 7th Semester under the supervision of

Mr. Ranbir Kalita, Guest Faculty, Mechanical Engineering, Jorhat Engineering College, Jorhat

(Assam).

The matter presented in this report has not been submitted for the award of any other

degree of this or any other University.

Partha Pratim Borah (M-27/13) Kaushik Kalita (M-40/13)

Sabir Hussain Choudhury (M-48/13) Sultan Ahmed Chowdhury (M-49/13)

SUPERVISOR’S CERTIFICATE

This is certified that the above statement made by the candidate is true to the best of my

knowledge.

Date: (RANBIR KALITA)

Place:

(Supervisor)

CERTIFICATE OF EXAMINATION

The viva-voce examination of the above candidates of 7th semester B.E. Mechanical Engineering on their project has been held on……………………………….and found

satisfactory.

……………………… ……………………… ………………………

Supervisor H.O.D. External Examiner

i

ACKNOWLEDGEMENT

A work of this nature while entailing a lot of personal effort cannot be completed

without the help and guidance of some experienced personalities. The overwhelming joy

experienced throughout the project work was the sincere help we received from many

personals and we acknowledge with deep and heartfelt gratitude to their good will and active

support during our work.

The main inspiration and driving force behind the task of preparing this project, without

which it would not have been possible for us to carry out the job satisfactorily is the sincere

guidance of our project guide Mr. Ranbir Kalita Sir, Guest Faculty, Mechanical Engineering,

Jorhat Engineering College, Jorhat (Assam).

We are indebted to Prof. Dr. Parimal Bakul Barua Sir, Head of The Department,

Mechanical Engineering of Jorhat Engineering College, Jorhat (Assam), for giving his

valuable time and suggestions.

Finally we would also like to acknowledge and extend our heartfelt gratitude to all

those who directly or indirectly helped us in conducting the project successfully.

Partha Pratim Borah (M-27/13)

Kaushik Kalita (M-40/13)

Sabir Hussain Choudhury (M-48/13)

Sultan Ahmed Chowdhury (M-49/13)

ii

ABSTRACT

This project includes the application of KINETIC ENERGY RECOVERY SYSTEM

(KERS) by means of flywheel energy storage. KERS is presently used for sports vehicles

and other hybrid road vehicles. But our project aims at implementing this energy saving

technology in a bicycle and determines its efficiency under different situations.

KERS is a system for recovering the moving vehicle’s kinetic energy under breaking

and also to convert the usual loss in kinetic energy into gain in kinetic energy. When riding a

bicycle, a great amount of kinetic energy is lost while braking, making start up fairly

difficult. Here we used mechanical kinetic energy recovery system by means of a flywheel to

store the energy which is normally lost during braking, and reuse it to help propel the rider

when starting after a halt.

Kinetic energy is transferred to the flywheel from the rear wheel via chain drive

through an engagement-disengagement mechanism. The flywheel stores the available energy

during halt and powers back the rear wheel while stating up.

The recovery speed of KERS bicycle is very low theoritically and even lower in

practical operation. This recovery speed and thus efficiency can be increased by increasing

flywheel weight. But giving too much weight to the cycle will hinder normal cycling.

iii

iv

CONTENTS

Page No.

CANDIDATES’ DECLARATION i

ACKNOWLEDGEMENT ii

ABSTRACT iii

CONTENTS AND LIST OF FIGURES iv-v

CHAPTER 1 INTRODUCTION 1

1.1 Introduction 1

1.2 Objective 3

1.3 KERS Bicycle Working 3

1.4 Design Requirements 3

CHAPTER 2 LITERATURE SURVEY 6

CHAPTER 3 THEORETICAL ANALYSIS 7

3.1 Collected Data 7

3.2 Theoretical Formulae 7

CHAPTER 4 FABRICATION PROCESS AND COST 9

4.1 Frame Modification 9

4.2 Flywheel 9

4.3 Axle 10

4.4 Sprocket` 10

3.5 Lever 10

CHAPTER 5 RESULTS 12

CHAPTER 6 CONCLUSION 15

v

REFERENCES 16

LIST OF FIGURES Page No.

1.1 KERS system installed in a bicycle Bicycle 1

4.1 Modified Frame 9

4.2 Flywheel 10

Chapter 1

INTRODUCTION

1.1 Introduction

KERS system is an eco-friendly mode of energy conservation. The main

component of the KERS is the flywheel. Flywheels are popularly known for their

energy storing capabilities. It finds its place in almost every mechanism that involves

gears and centrifugal motion. From the literature survey, it has been found that the

flywheels are 10 to 15 percent more efficient in storing kinetic energy than compared

to the conventional batteries. But the main concern in using a flywheel is, when the

energy gets stored it has to be dissipated within a matter of seconds.

In the bicycle fabricated in this project, Kinetic Energy is provided to the

flywheel from rear wheel via chain drive through an engagement-disengagement

mechanism. When the brakes are applied, the flywheel is disengaged from the chain

drive. Due to momentum, the flywheel continues to rotate during the halt even though

it is not getting power input from the rear while. Thus, it acts as a mechanical device

to conserve energy, but that is for a small duration of time.

Additional Sprockets Flywheel

Rear Wheel

Figure 1.1: KERS system installed in a bicycle Bicycle

1

Chapter 1

When the rider starts to paddle again, the flywheel is engaged to the chain

drive. Now the remaining conserved Kinetic Energy in the flywheel is transferred

back to the rear wheel of the bicycle. Thus the rider needs to apply lesser amount of

effort to start than the effort required to start the same without KERS.

Installation of a KERS in a bicycle using flywheel is motivated by the desire to

test the concept of Mechanical KERS and its applicability in a bicycle.

There are two basic types of KERS systems i.e. electrical and mechanical. The

main difference between them is in the way they convert the energy and how that

energy is stored within the vehicle.

Battery-based electrical KERS systems require a number of energy

conversions each with corresponding efficiency losses on re-application of the energy

to the drive line. The global energy conversion efficiency for electrical KERS is 31%-

34%.

The mechanical KERS system stores energy mechanically in a rotating

flywheel. Thus, it eliminates the various energy conversions and provides a global

energy conversion efficiency exceeding 70%, more than twice the efficiency of an

electrical KERS system.

On a flat road, the cyclist can maintain a fixed cruising speed to get from one

point to another. Globally all roads are flat with different types of obstacles such as

intersections, cars and turns that force the cyclist to alternately reduce speed and

accelerate again. A flywheel can temporarily store the kinetic energy from the rear

wheel when the rider needs to slow down. The energy stored in the flywheel can again

be used to bring the cyclist back to the cruising speed. Thus, the cyclist can recover

the energy that would normally be lost during braking. In addition to increased energy

efficiency, the flywheel-equipped bicycle is more fun to ride since the rider has the

ability to boost up speed.

2

Chapter 1

1.2 Objective

The main objective of the project is to install a flywheel based mechanical KERS in a

bicycle to reduce the human effort in restarting the bicycle after a small halt. Also, it

will be tried to evaluate the weight of flywheel required for maximum percentage of

energy recovery for different weight of riders.

1.3 KERS Bicycle Working

The lever installed in the cycle is applied when the speed of the cycle needs to

be reduced. This action slows down the cycle but correspondingly rotates the

flywheel. Also while riding down the hill, a great amount of energy can be harvested

in the flywheel. Thus, the power available in the flywheel can be utilized as per

requirement in climbing up the hill or picking up speed after a halt in traffic jam.

Following are the main working steps of the flywheel installed bicycle system:

Step 1: Rider starts paddling. Clutch is engaged and motion is transferred from

rear wheel to flywheel via chain drive.

Step 2: Flywheel is disengaged during a small halt.

Step 3: Flywheel stores the kinetic energy.

Step 4: Again the flywheel is engaged to the chain drive and the rider starts

paddling.

Step 5: Motion transfer from flywheel to rear wheel via chain drive.

1.4 Design Requirement

There are many requirements that need to be met to produce a product that is

both feasible and optimal. There are also some constraints, both geometrical and

engineering that also need to be satisfied. The following list describes these

requirements and constraints:

(a) Store energy while braking

This is the main requirement and overall objective of the project and must

be suitable to meet the rider's needs.

3

Chapter 1

(b) Return energy to start up

Once the energy is stored in the system, it is necessary to have a simple

way to release this energy back to the user in a positive way. This can be

accomplished with an easy to use clutch system.

(c) Must fit on a bicycle

This is one of the most difficult constraints to achieve and most important

because we are dealing with such confined spacing. The objective is to fit

the flywheel and accessories in the bicycle without affecting the sitting

and paddling comfort of the rider.

(d) Light weight

The importance of having a light weight design is driven by the rider's

desire to have a bicycle that is more portable. This is also a direct trade off

with how much energy can be stored in the flywheel.

(e) Good stopping force

The force required to stop is dependent on the stopping range and the

comfort levels of the rider. It is also related to the possible flywheel

features.

(f) Inexpensive and affordable

This product must be affordable and be desirable too.

(g) Manufacturability and Availability

The product should be easy to manufacture and parts must be cheap and

easily available.

(h) Should not hinder the normal riding

To have a successful accessory for a bicycle, the rider should not feel a

noticeable change in the riding performance or in the normal riding

motion.

4

Chapter 1

(i) Controlled Release

The energy that is released back to the user must be done in a safe and

Manageable way.

5

Chapter 2

LITERATURE SURVEY

D. K. Naresh Kumar et. al. [1] designed and fabricated a flywheel bicycle with mobile

charger which fetches the kinetic energy produced from the pedaling power. While pedaling

the bicycle, the flywheel also rotates by the mode of chain arrangement which in turn slightly

increases the speed of the bicycle. This setup is more applicable while riding bicycle on the

highways. By the rotation of the wheel, the driving wheel of the dynamo also rotates which in

turn produces 5V of AC which is converted to DC. Hence the back wheel rotates while

pedaling the bicycle and the kinetic energy produced is recovered as the extra movement of

the back wheel of the bicycle by the rotation of the flywheel. Author mentions that this

system has potential to serve as a alternative energy source in near future.

Nishad Kumbhojkar et. al. [2] in their research word found that the flywheel and

transmission add weight to the bicycle. The increased weight will add to the energy required

to accelerate the bicycle and to ride it uphill. However, once the rider has provided the energy

to reach a cruising speed, the flywheel reduces the energy cost of slowing down from this

speed since it aids in subsequent acceleration. Roads are optimal environment for the

flywheel bicycle because it’s flat and there are lots of reasons for the cyclist to slow down.

Considering weight criteria author found that optimum weight for better efficiency is 5 kg for

normal cycling.

U. Mugunthan and U. Nijanthan [3] conducted an overdrive test to find out the

efficiency of their flywheel based KERS installed bicycle. It has been found out that the

flywheel supplies an energy with which the cycle could move forward by 10% of the given

input. Depending upon the input given, the efficiency varies. But only 10% can be obtained

by this principle.

Sreevalsan S Menon et. al. [4] in their research work found that the flywheel and

transmission add weight to the bicycle. The increased weight will add to the energy required

to accelerate the bicycle and to ride it uphill. However, once the rider has provided the energy

to reach a cruising speed, the flywheel reduces the energy cost of slowing down from this

speed since it aids in subsequent acceleration. Roads are optimal environment for the

flywheel bicycle because it’s flat and there are lots of reasons for the cyclist to slow down.

Considering weight criteria author found that optimum weight for better efficiency is 5 kg for

normal cycling.

6

Chapter 3

THEORETICAL ANALYSIS AND ASSUMPTIONS

The KERS system is most efficient only when power requirement is of fluctuating nature.

The additional weight is outweighed by the ability to recover energy normally lost during

braking. Thus the additional extra weight does not make it difficult for the rider. Also a lever is

provided that helps in deciding the time period of activity. The overall result is that the KERS

system is efficient in storing the energy normally lost in braking and returns it for boosting.

3.1 Collected Data

Component Measurements

Flywheel Weight 4.5 kg

Flywheel Radius 12 cm

Flywheel Thickness 1.3 cm

3.4 Theoretical Formulae

The formula used for evaluation of efficiency is:

Efficiency= 𝐾𝑖𝑛𝑒𝑡𝑖𝑐 𝑒𝑛𝑒𝑟𝑔𝑦 𝑜𝑓 𝑡𝑕𝑒 𝑐𝑦𝑐𝑙𝑒 𝑏𝑒𝑓𝑜𝑟𝑒 𝑒𝑛𝑔𝑎𝑔𝑒𝑚𝑒𝑛𝑡 𝑜𝑓 𝑓𝑙𝑦𝑤𝑕𝑒𝑒𝑙𝐾𝑖𝑛𝑒𝑡𝑖𝑐 𝑒𝑛𝑒𝑟𝑔𝑦 𝑜𝑓 𝑡𝑕𝑒 𝑐𝑦𝑐𝑙𝑒 𝑎𝑓𝑡𝑒𝑟 𝑒𝑛𝑔𝑎𝑔𝑒𝑚𝑒𝑛𝑡 𝑜𝑓 𝑓𝑙𝑦𝑤𝑕𝑒𝑒𝑙

Energy = 1

2 × Mass of System (Bycycle+flywheel+rider) × (velocity of the system)2

7

Chapter 3

Therefor,

Efficiency = Mass of the system ×(𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑜𝑓 𝑡𝑕𝑒 𝑐𝑦𝑐𝑙𝑒 𝑏𝑒𝑓𝑜𝑟𝑒 𝑒𝑛𝑔𝑎𝑔𝑒𝑚𝑒𝑛𝑡 𝑜𝑓 𝑓𝑙𝑦𝑤𝑕𝑒𝑒𝑙)

Mass of the system ×(𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑜𝑓 𝑡𝑕𝑒 𝑐𝑦𝑐𝑙𝑒 𝑎𝑓𝑡𝑒𝑟 𝑒𝑛𝑔𝑎𝑔𝑒𝑚𝑒𝑛𝑡 𝑜𝑓 𝑓𝑙𝑦𝑤𝑕𝑒𝑒𝑙)2

2

= (𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑜𝑓 𝑡𝑕𝑒 𝑐𝑦𝑐𝑙𝑒 𝑏𝑒𝑓𝑜𝑟𝑒 𝑒𝑛𝑔𝑎𝑔𝑒𝑚𝑒𝑛𝑡 𝑜𝑓 𝑓𝑙𝑦𝑤𝑕𝑒𝑒𝑙)

(𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑜𝑓 𝑡𝑕𝑒 𝑐𝑦𝑐𝑙𝑒 𝑎𝑓𝑡𝑒𝑟 𝑒𝑛𝑔𝑎𝑔𝑒𝑚𝑒𝑛𝑡 𝑜𝑓 𝑓𝑙𝑦𝑤𝑕𝑒𝑒𝑙)2

2

The formula used for evaluation of speed ratio is:

Speed ratio= 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑜𝑓 𝑡𝑕𝑒 𝑐𝑦𝑐𝑙𝑒 𝑏𝑒𝑓𝑜𝑟𝑒 𝑒𝑛𝑔𝑎𝑔𝑒𝑚𝑒𝑛𝑡 𝑜𝑓 𝑓𝑙𝑦𝑤𝑕𝑒𝑒𝑙𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑜𝑓 𝑡𝑕𝑒 𝑐𝑦𝑐𝑙𝑒 𝑎𝑓𝑡𝑒𝑟 𝑒𝑛𝑔𝑎𝑔𝑒𝑚𝑒𝑛𝑡 𝑜𝑓 𝑓𝑙𝑦𝑤𝑕𝑒𝑒𝑙

8

Chapter 4

FABRICATION AND COST

Frame Modification

The frame modification is the first part of the fabrication process. The frame

is modified by adding two mild steel bars to the bicycle frame. The frame should

have enough strength to carry the flywheel and the additional forces that comes

to play. The modification should not hinder normal riding. Also the modified frame

should have enough space in order to accommodate flywheel and lever assemblies.

This is shown in the figure.

Flywheel

The flywheel has to be bored centrally in order to place it over the axel. The

flywheel has to be so selected that the selected weight does not affect the bicycle

physics and the riding performance. The performance of the KERS system mainly

depends on the flywheel selection. The flywheel is shown in the figure.

9

Figure 4.1 : Modified frame

Chapter 4

Figure 4.2: Flywheel

Axle

The axle has to be made so as to carry the flywheel and the additional units.

The flywheel can be inserted over the axel then. The provision for axel placement is

provided in the modified frame. The axel is made to rotate on the two bearings

provided on the two bars. The axel should withstand the forces coming into play.

Sprocket

Two sprockets are used in fabricating the bicycle, one sprocket with higher

number of teeth and other with lesser number of teeth. The larger sprocket is placed at

the rear wheel end and the smaller sprocket at the axle end. The smaller sprocket is

taken from a standard bicycle sprocket-bearing. The larger sprocket is collected from

a rickshaw.

Lever

The lever used in this project is a tong shaped lever which helps to engage and

disengage the flywheel from the chain drive whenever required.

10

Figure 4.2 : Flywheel

Chapter 4

COST

Sl. No. Element Quantity Cost (INR)

1 Tyre 2 280

2 Chain 3 450

3 Rod 2 300

4 Brake 1 120

5 Transportation 100

6 Labour Cost 500

Total Cost 1750

11

Chapter 5

RESULT

Experimentation was done using the fabricated bicycle to evaluate the performance of

KERS, when used in a bicycle.

The findings are shown below in tabular form:

Distance Travelled (km ) Avg. Speed (km/hr ) Maximum Speed ( km/hr)

0.5 10.4 15.7

0.5 12.7 16

0.5 12.4 16.8

0.5 13 17

0.5 12.1 17.2

0.5 11.2 17.4

Speed before

engagement(km/hr)

Speed after

engagement(km/hr)

Speed Ratio

12 3.17 3.78

14 3.93 3.56

16 4.85 3.29

18 5.975 3.01

20 6.96 2.87

12

Distance Travelled (km ) Avg. Speed (km/hr ) Maximum Speed ( km/hr)

0.5 15.8 20

0.5 16.2 21

0.5 15.4 19

0.5 16.6 22

0.5 15.6 20

0.5 16.4 22

Normal Bicycle Speed without KERS Installed

Bicycle Speed with a Flywheel Installed but Without Engagement

Table for Speed Ratio

Chapter 5

Increasing the speed of bicycle before engagement increases the efficiency of the

KERS

13

2

4

6

8

10

12

14

10 12 14 16 18 20 22

Effi

cie

ncy

Speed before flywheel engagement

Efficiency vs Speed

efficiency

Speed before

engagement(km/hr)

Speed after

engagement(km/hr)

Efficiency (%)

12 3.17 7

14 3.93 7.9

16 4.85 9.2

18 5.975 11.02

20 6.96 12.1

Table for Efficiency

Chapter 5

The extrapolated speed for 30% efficiency is approximately 50km/hr, which is not

practically achievable for a normal bicycle rider.

14

2

7

12

17

22

27

32

10 20 30 40 50 60

Effi

cie

ncy

Speed before flywheel engagement

Efficiency curve with Extrapolation

efficiency

Chapter 6

CONCLUSION

The efficiency of the system could have been increased if the losses due to friction

and air resistance were minimized.Clutch mechanism using frictional clutch plate would give better results by proper, smooth and fast engaging and disengaging. A less weight bicycle would allow the rider to incorporate a heavy mass flywheel which would harvest more kinetic energy. Future Scope: 1) A clutch system will help to maintain a smooth engagement and disengagement in the KERS.

2) Proper enclosing of the flywheel can prevent losses due to air friction. 3) Exact flywheel installation would give proper balance.

15

REFERENCES

[1] D. K. Naresh Kumar, M. Sarath Kumar, S. Murugavel, M. Pradeep, P. Prasath

(November 2014) “Design and Fabrication OF Flywheel Bicycle with Mobile

Charger”, International Journal of Scientific Research, Volume 3, Issue 11, ISSN

No 2277-8179.

[2] Nishad Kumbhojkar, Kunal Mohite, Anand Kulkarni, Sanket Patil (April 2015)

“Design and Implementation of Kinetic Energy Recovery System (KERS)

Bicycle”, International Journal of Mechanical Engineering and Technology

(IJMET), Volume 6, Issue 4, pp. 101-108, ISSN 0976 – 6340 (Print), ISSN 0976 –

6359 (Online).

[3] U. Mugunthan, U. Nijanthan (May 2015) “Design and Fabrication of Mechanism of

Recovery of Kinetic Energy Using Flywheel”, International Journal of Emerging

Technology and Advanced Engineering, Volume 5, Issue 5, ISSN 2250-2459.

[4] Sreevalsan S Menon, Sooraj, Sanjay Mohan, Rino Disney, Suneeth Sukumaran

(August 2013) “Design and Analysis of Kinetic Energy Recovery System in

Bicycles”, International Journal of Innovative Research in Science, Engineering

and Technology, Vol. 2, Issue 8, ISSN: 2319-8753.

[5] “Theory Of Machines” (2005), R.S. Khurmi, J.K. Gupta, S. Chand, pp. 570-611,

ISBN : 81-219-2524-X.

[6] “Design Of Machine Elements” (3rd edition), V. B. Bhandari, McGraw Hill

Education, pp. 749-767, ISBN (13 digit) : 978-0-07-068179-8, ISBN (10 digit) : 0-

07-068179-1.

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