Flywheel Bike KERS

A kinetic energy recovery system stores energy during braking to later assist with acceleration instead of wasting the energy as heat on the brakes. This is very similar to regenerative braking in electric and hybrid cars, but in some cases the energy can be stored in a

flywheel

and if you are a subscriber to this channel, you will know that I love

flywheel

s, so let's build a bicycle with a recovery system flywheel kinetic energy. The plan is to use the

bike

I made earlier to run on air from another video as the frame is a simple tubular design and has plenty of room for a flywheel, plus I already have a CAD model so it will save some time design.

I can calculate the size of the steering wheel I need, which appears to be approximately 30 centimeters in diameter. So where can I get a steering wheel like that? I have a CNC router to cut parts for many of my projects, but I have never cut anything heavier than aluminum. Ideally, the flywheel should be made of steel, since steel is three times denser than aluminum. While searching for steel sheets on the Internet, I found a group of sellers on eBay selling laser-cut steel discs with the perfect dimensions that I need. , which saves me a lot of work to turn this steel disc into a flywheel.

First I measured and drilled some holes. on a friend's drill, but because I measured the hole positions by hand, they probably won't be perfectly aligned, so I placed the wheel a distance from my camera and took a photo. I can then import this image into my CAD software and make a model of the steering wheel that shows that the center of the drilled holes is only off by 0.086 millimeters, which was a pleasant surprise. I can also use this template to design some side plates that would correct for this slight misalignment and allow the bearings to be mounted on each side of the steering wheel, the purpose of the disc brake will become clear later, the next step was to make the brackets that will hold the steering wheel inside the bicycle frame.

These were cut from a six millimeter thick sheet of aluminum which should provide enough strength to keep the flywheel from coming loose at high revs, so it was time to check if my measurement and design were correct by connecting everything to the

bike

and there we have it. , a steering wheel on a bicycle, now we have to figure out how to connect it to the rear. wheel to capture braking energy and help with acceleration in an ideal world the bicycle wheel and steering wheel should be coupled using an infinitely variable transmission, this would allow the bicycle to travel at a certain speed and the steering wheel to be stationary when The bike slows down the flywheel will accelerate at a really high rpm, the only problem is that this is very difficult to do mechanically as you would basically need an infinitely variable gear ratio, so the next best solution is to use a clutch system that can engaging and disengaging the steering wheel during braking and acceleration, this is not an original idea and in fact other people have built very similar bikes in the past and you can find their videos here on youtube, however I couldn't find much information about how effective their bikes are.

So what do you do when you can't find more information on a topic? You perform the experiment yourself to place the clutch inside the bicycle frame. I need to make this plate on my cnc, which took a while to cut and was quite a waste. of material and space for the memory card, but it can be attached to another plate that has specially designed cutouts for mounting brake pads. It can then be placed on the same axle as the flywheel and pressed against the brake disc to act as a clutch, so that not only are bike parts cheap and easy to come by, but it is also a clutch mechanism.

Really compact that easily fits inside the bike frame at normal cycling speeds. The bike wheels don't spin much faster than about 300 rpm, but I need this flywheel to spin around 2000 rpm for storage. the energy needed to get going again, so there must be a large gear ratio between the bicycle wheel and the steering wheel, this means that the steering wheel will rotate in the opposite direction to the bicycle wheels, but I hope that that's not a problem. So the clutch design works a little, but it also sticks a lot. The clutch plate I cut earlier should be one piece to allow this small gear to fit around the small bearings.

However, my cnc router is not very good at cutting perfectly round holes. These thin-walled bearings are slightly squeezed out of being circular, causing them to spin terribly and barely slide along the shaft, causing the clutch to bind. The solution to this was to increase the gear size and use a larger bearing, but this reduces the gearing. relationship to the rear wheel, so I had to make a larger rear sprocket to maintain the same relationship between the wheels to engage the clutch. I 3D printed two discs with thread-like earrings that, when rotated, separated. These had to be really compact.

There is only about six millimeters of space between the clutch gear and the side plate, but it appears to have a decent amount of pushing force due to the physics of the mechanical advantage. I chose to operate the clutch using the left lever like a motorcycle, but this works. the opposite of a motorcycle, as pulling the clutch lever actually engages the clutch rather than disengaging it. The reason for this is that I don't want the clutch to be engaged all the time when I ride because it requires a lot of energy to turn the steering wheel, so pulling the lever in will add resistance and act as a brake, then when the bike is Completely stopped, the flywheel will continue to spin with its stored energy and I can just pull the lever again to engage the clutch and get the bike up to speed again, I think.

It's time to take a test. I guess I ride like a normal bike. Wow, these gears are noisy, so I'll pick up some speed and then engage the clutch and see what happens. the clutch needs to be tightened, it doesn't have full grip, the speed increases, the speed increases and then we activate the clutch and now we accelerate. I think we still need to adjust the clutch a little bit, it doesn't bite enough to lock it completely, so let me get it a little. tools, oh, that's much better, that slowed me down quite a bit, in fact, let's see if I can speed up again and that's not bad, not bad.

I think the problem is that by the time the clutch is fully engaged it has already slowed me down a bit. a substantial amount, so I'm going to try to spin it while pedaling to get really high revs, okay, that's quick, let's turn it around and let's look at what's going on here. Let's imagine that the two lines on the left show the relative speed of The bicycle and the steering wheel while you are riding the bicycle are at high speed and the steering wheel is not rotating. Then when I engage the clutch, the flywheel starts to spin and the bike slows down to the point where the flywheel matches the speed of the clutch.

From this point the steering wheel can't turn any faster, so they both continue at a constant speed until I use the bike's normal brakes to stop it. Now the bike has zero speed but the steering wheel turns at about half speed. the bike had at the beginning, so when the clutch is reengaged, the bike accelerates as the flywheel decelerates and they both meet in the middle again once their speeds match, but if I accelerate the flywheel while riding, the fly will control a lot more energy as it spins much faster and then I can use the bike's normal brakes to stop it.

Now we have a much larger speed difference between the bike and the flywheel, so when I engage the clutch, the final speed of the bike. It's a lot faster so that's the problem, I can't charge it just by braking, it has to charge when driving, come on, start it, do it, God, then we come to a complete stop and then accelerate, come on, high speed, high speed, high speed, high speed. and that was a little scary. I had some tire weights mounted here, two 10 gram tire weights and one just came loose and hit me in the leg.

You have to be traveling at pretty high rpm for that to come out right. I think I found the weight of the tire. We need to go in and make a cup of tea. I love it, okay, let's go over some of the numbers on this flywheel bike setup. The weight of the flywheel is about 5.5 kilograms and the fastest I turned it was 2300 rpm, which is stored energy. About 1,800 joules To put that in perspective, a small battery stores five to six times that amount of energy, however, you can't charge and discharge one of those batteries as fast as you can like a flywheel, so which have very different characteristics. applications in terms of speed recovery achieved by the steering wheel, the initial braking technique only recovered about 22 percent of the bicycle's original speed and the second technique of turning the steering wheel before braking achieved a speed recovery of about 40 , but the act of having Pedal to turn the steering wheel beforehand requires a lot of effort, that's where the extra energy comes from, also because energy increases with speed squared, the actual energy efficiency never exceeds 15 percent, but it does about years ago I carried out some tests on my electrical DIY. bike and its regenerative braking and during a straight-line acceleration and deceleration test its efficiency was just 15.7 percent, so maybe the flywheels aren't so bad after all.

If you enjoyed this video, it would be great if you could leave a thumbs down. If you are new to my channel and want to see other projects similar to this, click Subscribe below and a big thank you to all my followers on patreon.com for making this project possible. Honestly, I couldn't make them. Crazy projects without your support, so thank you once again, thank you again for watching and I'll see you in the next video. Bye, let's quickly test the gyroscopic effects of the steering wheel. Actually, it doesn't seem that bad.