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
3134%. 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= ^2
Where, I is the moment of inertia 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.