Flywheel cycle is a system for recovering the moving vehicle’s kinetic energy under braking and also to convert the usual loss in kinetic energy into gain in kinetic energy. In the current project work we have found that when riding a bicycle, a great amount of kinetic energy is lost while braking, making start up fairly hard (difficult). Here we are proposed to make 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 speed up the rider when starting. The rider can charge the flywheel when slowing or descending a hill and boost the cycle when accelerating or climbing a hill. This will help to reduce for starting peddling effort.
Principle of flywheel
A flywheel used in machine serves a a reservoir which stores energy during the period when the supply of energy is more than the requirement and releases it during the period when the requirement of energy is more than supply
Flywheel cycle is collection of parts which stores kinetic energy under deceleration and release stored energy when we require acceleration and provide a boost. In traditional cycle kinetic energy during braking is converted into heat energy and reduces efficiency of cycle. Cycle with regenerative braking system converts this kinetic energy with the help of proper mechanism to store in flywheel.
Main two types of KERS
Main deference between them is conversion of energy and storage of energy within the cycle in electrical system energy conversion reduces efficiency and increase loss while in mechanical system rotating flywheel use which reduce any type of conversion of energy due to which that 70% efficient which is twice of electrical system.
Fig.1 Flywheel regenerative braking Bicycle
‘ Reduce Human Effort For Peddling After Braking
‘ Easy Frame Modification In Traditional Cycle
‘ Total Efficiency Is 10% More Than Total Effort Applied
‘ Can Be use As Exercise Or Gym Cycle
‘ Centrifugal Force Of Flywheel Consider When Bicycle Take A Turn
‘ Gyroscopic Effect Not Negligible
‘ Cycle Weight Increases
‘ Less Safety As Compared To Traditional Cycle
‘ REGENERATIVE BICYCLE WORKING
First of all when rider apply pressure on paddle main sprocket stars to rotate due to which rear sprocket also rotate using a chain drive system this is working of traditional bicycle but in flywheel cycle rear sprocket is connected or welder with another big sprocket of 56 teeth due to rotational motion of rear sprocket 56 tooth sprocket also rotates at same speed as of rear sprocket this big 56 teeth sprocket is connected to 13 teeth sprocket which is mounted on a modified frame this sprocket is welded to a clutch plate which is circular in shape which is mounted on a bearing.
A clutch is use to engage and disengage the clutch plate with flywheel with leaver mechanism also flywheel is mounted on rod placed in between the frame and a bearing is placed in bearing which provide smooth and efficient rotation of flywheel now this whole mechanism is connected to clutch which has two mating part which are controlled by clutch wire which is connected to brake now when rider starts peddling rear sprocket rotates due to which 56 tooth sprocket rotates this sprocket is connected to 13 tooth sprocket using chain drive due to which clutch plates rotates which help in rotating the flywheel now when brake is applied clutch wire is pulled due to which clutch plate gets disengage an flywheel rotates freely on kinetic energy which is stored in flywheel in form of kinetic energy now when brake is released then clutch also gets engaged due to which clutch plate and flywheel gets engaged and now this energy stored in flywheel gives boost to rider which reduce starting effort of rider while paddling here clutch plate and flywheel are connected using friction due to which some energy loss could take place which could reduce the efficiency of cycle this is working of flywheel bicycle
This mechanism works on normal route or place where traffic is less but when traffic jam or place where speed is low energy stored in flywheel is negligible instead of that it takes more effort for rider for peddling so we have develop a smart switch due to which once when the switch is on flywheel remains disengaged permanently until the switch is not of due to this switch place where more traffic is there no loss or conservation of energy take place
This were the two working principle of flywheel cycle
‘ TYPES OF KERS
KERS can be classified as follows:
The selection system is based on efficient, cost, weight, space, purpose
‘ MECHANICAL KERS SYSTEM
In this system flywheel use as storage device which is connected from the drive line with use of shaft and gears. Kinetic energy obtain through pedalling effect in excel helps the flywheel to rotate and storage energy in it. Unlike another KERS method the conversion of energy of one type another type is not done due to this system energy loss low and efficiency is high. It is one of the cheapest KERS method as compared to another KERS method.
‘ ELECTRON-MECHANICAL KERS SYSTEM
It is combination of mechanical+electrical system instead of batteries and capacitor flywheel is used for store energy. Main reason of this system is high weight and limited space this flywheel spines of very high speed in vacuum environment this flywheel as metal partial embaded on flywheel due to it works permanent magnet.
‘ HYDRAULIC KERS SYSTEM
Based upon purpose This system is alternate to the traditional KERS system. This system has some limitation as well as advantage in this system compressor is use to compress fluid and store in pressure tank which has pressure gauge when paddling is done. Paddling force compress fluid at certain level. Storage tank when we need to release this energy it is release through a valve which is connected to a chain system due to which when pressure is release. Kinetic energy is obtain from pressure engage boast is gain while exiling
‘ ELECTRONIC KERS
In this KERS rotational energy is captured by motor which is connected to battery which electric energy obtain by converting it from kinetic energy is stored. The main disadvantage system is the loss of energy while conversion of energy also battery become hot due to this conversion system is require to cool down the battery.
‘ DESIGN REQUIREMENTS
There are many requirements that need to produce a optimal solution of our component. There are also constraints, both geometric and engineering that also will fulfill.
Requirements & constrains
‘ energy Store while braking
This is the main purpose. Of this system which suitable for rider.
‘ energy Return to start up
Once the energy is stored in the flywheel it is release in the simple way when we required for this facility we made innovative chain drive system which is simple and user friendly
‘ Must fit on a bicycle
This is most important and difficult constrain to achieve. We make this all system in confined space. That takes also basic accessories and flywheel also.
‘ Light weight
This constrain depends upon riders smooth control on flywheel bicycle. We make bicycle with flywheel in normal weight and then bicycle become more portable and more movable.
‘ Good stopping range
The stopping range is important because this bicycle not in only theory when we use this bicycle practically means in real life many sensitive points we faced so we also weight on this constrain.
‘ Good stopping force
Stopping force should be such that cycle should stop easily without discomforting riders.
‘ Inexpensive and affordable
This system should be design in such a way that it is cost effective and could be affordable for all class of people.
‘ Safe to user and environmentally friendly
Safety is most important part of design. A cycle design is a such way that it is safe as well as environmental friendly which is the most important aspect for design in cycle.
‘ Aesthetically pleasing
Bicycle should be fully functional as well as it should have good looks .
Design should be modular so it can be easily adapted with other cycle at least cost.
‘ Should not hinder normal riding
Design of bicycle in such a way that the joy of riding of rider should not be disturbed.
‘ Controlled release
The energy that is released back to the user must be done in a safe and manageable fashion. This can be a consideration after the prototype is completed.
‘ FABRICATION PROCESS
A. Frame Modification
Frame modification is first as well as important part of fabrication process. Frameis made of steel tube which gives additional strengths to bicycle .Frame modification should be done in such a way that it should be safe as well as it should not hinder normal bicycle riding. It should be such a way in order to accommodate all mechanism like flywheel and clutch assembly.
Flywheel used in machine serves a reservoir which store energy and supply of energy more than requirements and release during the period when requirement of energy is more than supply. in flywheel a hole is made in which bearing is place so that flywheel can rotate freely on axel. So due to this reason flywheel should be selected in such a way that bicycle fiscal and riding performance not disturb. Bicycle Performance mainly depend selection of flywheel. It should be arranged in such a way that clutch accessories has provision in it.
Fig. 4 Works on Flywheel
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 by applying a lever mechanism incorporated with a spring assembly for providing return mechanism. Linear clutch movements have to be made possible. For this purpose two cylindrical rods can be used. One end of the each rod was variably cut. This variable length is female part of another. One part of this is fixed near the frame side. This can be achieved by welding the part. Another part is made rotator. This part can be rotated by applying force on it from lever via cable. This moves only partially over fixed one and firstly this is hold in position by a spring arrangement.
Two sprockets have to be used. The gear ratio is to be taken in to account here. 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.
The axle has to be made so as to carry the flywheel and clutch units. The flywheel can be inserted after bearing is added to it and if variable diameter is provided on axle within mid-point the flywheel can be made to be inserted from one end and it automatically locks in the middle of the axle over which it rotates. Also the clutch units sequentially clutch plate and the fixed and moving rods along with its mechanism can be mounted over the axle. The provision for axle placement is provided in the modified frame. The axle should withstand the forces coming to play.
The parts manufactured namely the flywheel with shaft and clutch plate helical disc assembly is mounted on the frame structure, which completes the manufacturing phase of the bicycle.
‘ RESULT AND ANALYSIS
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. The overall result is that KERS system is efficient in storing the energy normally lost in braking and returns it for boosting.
‘ Weight and Performance
Normally energy stored in the flywheel is directly proportional to the weight and radius. Hence increase in weight proves to improve the performance. But as we know that the maximum safe weight that can be used is limited due to frame properties and rider compatibility. And also after some extent the radius can’t be increased and the energy storage thus seems to be limited to some particular extend. This is also because of the fact that the total running speed is being reduced due to weight. Energy storage capacity increases with increase in weight but limitation seems to be the speed driving the flywheel. And performance of system is directly linked with the energy stored. Thus a graph can be plotted between performance and weight. Optimum value lies between 5 and 8 kg.
‘ Energy stored in flywheel
Thus Ek is directly proportional to the mass of the disc
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.
Energy is directly proportional to distance travelled, thus in case of flywheel bicycle more the distance travelled by the bicycle (flywheel engaged position) in one pedal more will be the energy saving and input energy reduction. Thus, (Difference in the distance of engaged and disengaged position/Distance in disengaged position)*100 Hence according to above method about 12% of energy reduction is obtained for the system. ‘
‘ Future possible modification
in future many modification can be done in this cycle which could improve efficiency of cycle as well as help the rider while riding bicycle such a future modification are as follows
(1) Connecting dynamo to generate electricity to give power to front and rear lights
(2) For charring mobile using dynamo
(3) Cruise control while riding in traffic jam or very slowly
(4) Connecting an extra sprocket to flywheel which can be connected to generator and battery setup to produce electrical energy
‘ Connecting dynamo to generate to generate electricity to run both front and rear light
‘ Now when rider travel slowly or through traffic jam efficiency of cycle decreases’ and more effort is to be given due to fly wheel so we could develop a cruise control which is one type of switch when it is on flywheel get permanently disengage from clutch plate and remain stationary due to which effort to rotate flywheel is eliminated
‘ Now when clutch plate is disengaged it would rotate continuously and energy is lost so we could connect a dynamo which will convert this lost energy in useful electrical energy which could be use to give power to front and rear light or could be use to charge mobile or other electric appliances
‘ This electrical energy produce by dynamo can be converted through a circuit so that voltage fluctuation does not take place due to which electrical appliances does not get damaged
‘ Nowadays cycle is use to generate electricity and use to charge lithium battery but this could be only possible by many design modification but instead of that if a sprocket is connected to flywheel and a motor is connected to sprocket using chain drive system then when cycle is free by peddling it motor would also generate electricity which can be stored in lithium battery
‘ Future prospect
‘ The idea of implementing kinetic energy recovery system (kers) in bicycle was implemented sucessfully with the help of few modification in the cycle
‘ now number of things could be incorporated with this cycle in future to make it more efficient,ergonomical as well as asthetical sound
1. By optimizzation of weight (flywheel,frame and oter mechanism) by using optimization technique or by analysing software such as ansys
2. improving transmission efficiency
3. taking in acount ergonomics of cycle so that rider could ride with great comfort
4. removal of extra part installed along with the frame to reduce weight of cycle
5. reduction of thickness of frame so that it does not create any type of hinderance while riding the cycle
6. designing a flywheel housing to ensure that flywheel is not in direct contact with enviroment
‘ Double Centrifugal Clutch Concept
A new concept was thought of with reference to the engagement and disengagement of the flywheel with the transmission that implies usage of centrifugal clutch. Need The implemented mechanism for the engagement and disengagement of flywheel is by using the clutch plate and the related mechanism; however this at times can be painstaking and tedious.
Thus by using a centrifugal clutch which by itself is an automatic type of clutch, the power flow can be made automatic. Hence by using double centrifugal clutch concept the transmission can be made independent of the driver control.
‘ Construction & Working
The proposed mechanism consists of 2 centrifugal clutches which are mounted on the bicycle axle as shown in the above fig. Consider the bicycle has reached a particular speed, say x m/s. This speed has been set as the pre-set speed for the centrifugal clutch i.e. as this particular speed the shoe
of centrifugal clutch 2 will touch the drum due to which the drum of clutch 2 will start rotating. This rotational energy will be transferred by the means of sprocket to the flywheel and flywheel will start rotating. However when the rotational energy of the flywheel is to be transferred back to the rear wheel, clutch 2 will be disengaged as rear wheel would be rotating at speed lesser than x m/s. Now centrifugal clutch 1 which is has a pre-set value of say y m/s (x>y) will be in engagement position i.e. there will becontact between drum and shoe. The clutch will rotate and energy will be transferred back to the rear wheel for pedal assist.
Thus as the value of engagement is set initially engagement between rear wheel and flywheel will be fully automatic without any human intervention.
Flywheel system used in bicycle satisfies purpose of saving parts of energy lost during braking. It is more efficient compare to conventional braking system. Flywheel system has a wide scope on future development in energy saving use of more efficient energy system could increase economic country and reduce pollution of world. Here we are concluding that flywheel bicycle has bright engineering scope to minimize energy loss and conserve energy.Here we implemented KERS system in bicycle with a engage and disengage clutch mechanism to gain more efficiency in this system many melting parts are use friction loss is found which can be improved. Due to this friction efficiency is reduce by using variable transmission efficiency increase and loss due to friction it’s reduce.
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