This document describes the design of a kinetic energy regenerative system (KERS) for bicycles. The KERS stores energy from the bicycle's kinetic energy during braking in a flywheel. It then provides extra power to the bicycle during acceleration by transferring energy back from the flywheel through a clutch mechanism. The document outlines the working principle, fabrication process including the flywheel, clutch, axle and sprockets. It discusses the advantages of mechanical KERS over electrical systems and concludes that KERS has the potential to improve bicycle efficiency by harnessing energy normally lost during braking.

1. DEPT . OF MECHANICAL ENGINEERING
ACHARYA INSTITUTE OF TECHNOLOGY
UNDER THE GUIDANCE OF
Mr. SACHIDANANDA K.B
BY GAUTHAM HARI MENON [1AY10ME021]
POOJAA PATEL [1AY10ME043]
ASISH MANI ABRAHAM [1AY10ME016]
SANJU TOM [1AY08ME049]
KINETIC
ENERGY REGENERATIVE SYSTEM IN
BICYCLES

2. CONTENTS
1. INTRODUCTION
2. MOTIVATION
3. ADVANTAGES
4. WORKING
5. FABRICATION
6. FABRICATION FLOW CHART
7. WEIGHT AND PERFORMANCE
8. ENERGY STORED IN FLYWHEEL
9. COMPARISON ANALYSIS
10. CONCLUSION

3. INTRODUCTION
 KERS is a collection of parts which takes some of the
kinetic energy of a vehicle under deceleration, stores
this energy and then releases this stored energy back
into the drive train of the vehicle, providing a power
boost to that vehicle
 KERS store energy when the vehicle is braking and
return it when accelerating.
 During braking, energy is wasted and with KERS we
will be able to harness some of this energy and in
doing so will assist in braking

4. MOTIVATION
 This design of KERS bicycle was motivated by a
desire to build a flywheel energy storage unit as a
proof of concept.
 On a flat road, the cyclist can maintain a fixed
cruising speed to get from point to point. Globally all
roads are flat with impediments such as intersections,
cars, and turns that force the cyclist to reduce speed,
then accelerate.

5. WORKING
 A crank wheel connected to the rear wheels always
rotates the clutch plate, connected in the flywheel axle.
 This is being achieved by using chain transmission at a
specified gear ratio.
 When a speed reduction is required, clutch is applied
which makes the contact between the clutch and
flywheel.
 Then the flywheel starts rotating, also the speed of
bicycle is decreased , thus regenerative braking system is
achieved.

6. WORKING
 On course energy is stored in flywheel.
 When we again rides the bicycle during which we would
apply clutches at this time as rear wheel rotation is lesser
compared to flywheel the energy gets transmitted from the
flywheel to the wheels.
 Thus we can reduce the overall pedalling power required.

7. FABRICATION PROCESS
FLYWHEEL:-
 The flywheel has to be bored centrally in order to place a
ball bearing so that flywheel can rotate over the axle.
 The performance of KERS system mainly depends
upon the flywheel selection.
 For clutch accessories there should be provisions in the
flywheel which is used to deliver and release energy from
flywheel.

8. FLYWHEEL

9. CLUTCH:-
 A clutch has to be provided so as to control the power
delivery and release from the flywheel.
 This can be achieved by providing a clutch plate that
is linearly moved to and fro.
 There are two cylindrical rods , one part of this is
fixed near the frame side and another part is made
rotatory.
 This part can be rotated by applying force on it from
lever via cable.

10. CLUTCH PLATE

11. AXLE
 The axle has to be made
so as to carry the
flywheel and clutch
units.
 The provision for axle
placement is provided in
the modified frame.
 The axle should
withstand the forces
coming to play.

12. SPROCKET
 Two sprockets have to be used.
 One sprocket with higher number of teeth is to be
selected and other having lesser number of teeth.
 The larger sprocket is to be placed at the rear wheel end
and smaller sprocket at the axle end.
 This is to ensure that we can provide larger
flywheel rotations so that energy storage increases.

13. TWO SPROCKETS USED
SMALLER SPROCKET LARGER SPROCKET

14. CLUTCH PLATE AND FLYWHEEL
MOUNTED ON AXLE

15. FRAME MODIFICATION FOR
FLYWHEEL MOUNTING

16. FABRICATION FLOWCHART

17. ADVANTAGES OF MECHANICAL
KERS OVER ELECTRICAL KERS
 The main difference between them is in the way they convert
the energy and how that energy is stored
within the vehicle.
 Battery-based electric KERS systems require a number of
energy conversions each with corresponding efficiency losses.
On reapplication of the energy to the driveline, the global
energy conversion efficiency is 31–34%.
 The mechanical KERS system storing energy mechanically in
a rotating fly wheel eliminates the various energy conversions
and provides a global energy conversion efficiency exceeding
70%, more than twice the efficiency of an electric system.

18. DOES THE EXTRA WEIGHT MAKE
ANY DIFFICULTY TO THE DRIVER?
 The flywheel bicycle increases efficiency on rides where
the rider slows often.
 The additional weight is outweighed by the ability to
recover energy normally lost during braking.
 Thus the addition of extra weight does not make it
difficult for the rider.
 Also clutch provided helps in deciding the time period of
activity.

19. WEIGHT AND PERFORMANCE
 Energy stored in the flywheel is directly proportional to
the weight and radius.
 Hence increase in weight proves to improve the
performance.
 Optimum weight of flywheel is between 5kg and 8 kg.

20. LIMITATIONS IN IMPROVING
PERFORMANCE
 The maximum safe weight that can be used is limited due
to frame properties and rider compatibility.
 After some extent the radius of flywheel can't be
increased
 The energy storage seems is limited to some particular
extend because of the fact that the total running speed is
being reduced due to weight.

21. ENERGY STORED IN FLYWHEEL
Energy stored in flywheel, Ek= ½ 𝐼ω^2
Where,
I is the moment of inertia
ω is the rotational velocity (rpm)
Moment of inertia, I = kmr^2
Where
k is inertial constant (depends on shape)
m is mass of the disc
r is the radius
Thus Ek is directly proportional to the mass of the disc.

22. COMPARISON ANALYSIS
CONVENTIONAL
BICYCLE KERS BICYCLE
 Distance covered less..
 Kinetic energy can not
stored.
 Normal acceleration.
 Speed is reduced only
using brakes.
 Distance covered more.
 Kinetic energy can be
stored.
 Extra acceleration due
to flywheel.
 Speed can be reduced
using both brakes and
clutch.

23. CONCLUSION
 KERS system saving a part of the energy lost during
braking.
 KERS system has a wide scope for further
development and the energy savings.
 Here we implemented KERS system in a bicycle with
an engaging and disengaging clutch mechanism for
gaining much more efficiency.

24. THANK YOU