1. 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. 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. 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. 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. 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. 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. 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. 8. FLYWHEEL
9. 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. 10. CLUTCH PLATE
11. 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. 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. 13. TWO SPROCKETS USED SMALLER SPROCKET LARGER SPROCKET
14. 14. CLUTCH PLATE AND FLYWHEEL MOUNTED ON AXLE
15. 15. FRAME MODIFICATION FOR FLYWHEEL MOUNTING
16. 16. FABRICATION FLOWCHART
17. 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. 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. 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. 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. 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. 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. 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. 24. THANK YOU