h a l f b a k e r yRenovating the wheel
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REVISED: Original Baked Submission Below:
What about a flywheel mounted between the wheel hub and drive train? A kinetic energy cache device where the engine power train would spin up the flywheel and the flywheel would power the hub and wheel. CVT/Torque Convertor connected on both sides.
Each
flywheel draws power as necessary from the power train. The hub and wheel would be powered and managed by the flywheel.
Aftermarket add on for most cars providing regenerative braking and instant torque for acceleration.
The flywheels are spun up to 100% when you turn on your car and have sensors to manage power so as to maintain 66% while driving leaving 1/3 capacity available to store kinetic energy captured during deceleration.
When you accelerate the flywheel provides instant torque to the wheel. More than enough to accelerate to 60 getting the car to speed. Allowing the engine to replenish flywheel energy over a longer time and at much lower RPM's (Just enough to overcome friction of the moving car and recharge the flywheel back to 66%)
When you decellerate/brake the flywheel engages the wheel to capture its rotational energy. In theory you would run mostly at engine idle speed or slightly above for steady driving.
Aftermarket kit might end up being a replacement hub/brake assembly and a controller specific to model of car.
The system will increase gas mileage because idling losses are eliminated. Deceleration energy is efficiently captured and stored in the flywheel without conversion to electricity.
Any Comments from the peanut gallery?
ORIGINAL
You've seen brake shields, wheel balancing rings and all sorts of car gadgets.
This idea is for an aftermarket set of 4 flywheels disks that mount onto your wheels. This is a pure mechanical device and is simply a spinning disk containing of a few pounds with a few ounces of mercury for lubrication and autobalancing.
As brakes are applied and the wheel slows this fly wheel addon will spin up and capture the kinetic energy.
While at stop it continues to spin and on acceleration it dumps its energy towards forward motion. If you park for a while the fly wheel will continue to spin until its energy dicipates through friction.
Should dynamically keep your wheels balanced, improve braking and assist acceleration while saving gas.
Centramatic wheel balancer
http://www.mrtruck.net/centramatic.htm
Kind of like this but heavier [Shapharian, Sep 19 2007]
Spinning Rims
http://www.youtube....ode=related&search=
A five-second video for those of you lucky enough to have never seen any. [baconbrain, Sep 19 2007]
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Annotation:
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Not sure "a few pounds" would have much effect. And am a bit worried about the liquid mercury (recycling hazard.) |
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A few questions:
How fast would the flywheels be rotating?
(to help calculate the energy storage)
What orientation (horizontal/vertical?)
Have you considered the forces generated while making turns?
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Neutral 'til we hear more. |
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Would this, by dramatically increasing the unsprung weight of the vehicle, make the ride quality awful? |
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"Purely mechanical?" That implies a clutched drivetrain. You cannot achieve better than 25% regeneration per stop-start: 50% for the stop, and 50% of that for the start. Those are perfect world assumptions, reality will be significantly less. I drew a bicycle version of this for my Mechanical Drawing class in 1985, and I realized then exactly what my best possible results would be. The bike would be rideable because the wheel is at full speed only at rest, and all its motion is utilized to restart the vehicle; in motion, the flywheel is at rest. |
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Okay, that's my knee jerking. If you were to operate this via a very stout CVT, you could wring out considerably more for both recovery and reapplication, so then it starts to look like a pretty good idea. |
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Ford did a similar regen-only idea in their Tonka concept truck; it used hydraulics instead of a flywheel. I like that idea better since it doesn't specify minimum sizes and can be fit in to all kinds of spaces simply be routing the plumbing appropriately. |
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As an electrically driven flywheel, this concept is baked to a crisp. |
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If it's on the wheel, it's adding un-sprung weight, which is a bad thing. It's also getting hammered to death at every pothole. |
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It's also going to need a very complicated mechanism to somehow get the motion of the wheel into the flywheel. Something has to contact the car body, the ground or the air; or the flywheel just rotates with the wheel. Whatever makes it work should be the biggest part of this posting. |
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Otherwise, this is just a flywheel-assisted car, which has been done. |
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With carefully placed holes in the flywheels, they will act as sirens and when the noise ends you will know that they have stopped rotating. Blessed relief really. Phew, I'm glad that's stopped. At least it drowned out the mother-in-law for a while. |
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Disk is 250mm diameter and has a free spinning rotating mass of let's say 2kg at the rim (Picture a mini hula hoop with 2KG of ball bearings inside).. It's mounted behind the wheel rim through the lugs and is designed to pickup on the acceleration and deceleration of the vehicle. |
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When you decrease speed the free spinning mass inside the rim spins up to absorb the deceleration energy. When you accelerate the mass puts out all of its energy in supplement with the engine. |
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Only moving part is the free spinning mass (possibly ball bearings) inside the sealed rim of this disk. The unsprung weight is not significant as the energy is typically just absorbed for 15 seconds during braking and applied of 5 seconds during acceleration. |
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It's more like a kinetic energy cache. While cruising at steady speeds the disk spins and distributes its weight dynamically to keep the wheel always perfectly balanced. |
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This is not an electric flywheel / motor / generator and is not used to power anything. Just a device to pickup and store decelerating energy and apply it during acceleration. |
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Upon parking it should spin down by friction in 15 minutes. |
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Even if it's only 20% efficient it should decrease engine and braking load and increase gas mileage for city stop and go driving. |
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Maybe we can just throw a few KG's of ball bearings inside the tire to do the same things. |
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//When you decrease speed the free spinning mass inside the rim spins up// HOW?!?! What makes it do that? Elves? |
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When you write "spins up", it says that the flywheel somehow gets going at a higher RPM than the wheel had been doing. Which takes a mechanism of some sort; gears and whatnot. |
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Your lack of mechanism makes that impossible. It now seems that you want a dead-simple thing almost exactly like a "spinning rim" in priciple, that never rotates at a higher RPM than the wheel does. You hide it on the backside of the wheel, which means you must give it the equivalent of wide-diameter bearings and dramatically increase friction losses. |
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Well, if that's the design, it's not going to provide much energy at all. And that's AFTER you come up with a mechanism to couple the thing into the wheel for helping the acceleration. [-] |
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http://www.4crawler.com/4x4/ CheapTricks/ WheelBalance/index.shtml |
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"A week later a box arrived from Centramatic with the four wheel balancers. Closer examination revealed a galvanized steel center disc to which was crimped a plastic "donut" full of heavy steel shot suspended in a synthetic oil. Kind of reminded me of one of the old hula-hoops with the pellets inside that made a "shoop-shoop" sound as it spun. Each unit weighs about 5 pounds, or so. The inner hub cutout is 4-1/4" dia. and easily fits over the stock hub, the outer diameter is 12-1/2", so you should check that your rims have enough clearance inside for the balancer to fit, the plastic donut projects about 1-1/8" at its maximum thickness. They fit inside both my Toyota factory 15x6 rims as well as my 15x10 custom rims (both steel). There was not a lot of extra room, though, so be sure to measure your rims before ordering." |
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Yes, we know, those things have been around for years. The thing you need to explain is how that makes a //kinetic flywheel recapture energy for any car//? It doesn't do anything more than balance the wheel. |
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The heavy oil is going to keep the shot from rolling through the tube for more than a few fractions of a second, even under heavy braking. It is NOT a flywheel. |
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I have my own version of this idea. |
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//m a bit worried about the liquid mercury
(recycling hazard.)// Just use pre-1970's
mercury. It was safe enough back then. |
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i don't see how this has gotten this far. |
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I balance the wheels for a reason, (yes i balance wheels among other things) there's no need to balance the wheel after it has already been balanced. I don't know what the guy from Centramatic was thinking, unless he didn't have his wheels balanced... i have no idea how his Centramatic wheels or your idea would help balance a wheel. if you spin water in a closed container a little off center you will get a hell of a mess spinning around. |
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the only benefit would be a somewhat quicker launch from a standstill. but since most cars can spin there tires in first gear there's really no need for that either. all your doing is adding weight to the drivetrain and that's the worse place to add weight besides the valvetrain. that's why racers have ultralight flywheels. |
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/if you spin water in a closed container a little off center you will get a hell of a mess spinning around/ |
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Not necessarily. Above and below resonance frequency will give different results. |
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I'd held off voting until this point because I wanted to see if you could somehow save the concept. Instead, it just gets worse. |
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"the energy is typically just absorbed for 15 seconds during braking and applied of 5 seconds during acceleration." |
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"When you decrease speed the free spinning mass inside the rim spins up to absorb the deceleration energy." |
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"free spinning rotating mass of let's say 2kg at the rim (Picture a mini hula hoop with 2KG of ball bearings inside).." |
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MFD: magic and/or bad science. No mention is made of how the weights are spun up by the wheel as it decelerates. There is no energy absorbed by the flywheel if it is not somehow connected to the wheel. |
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2K at the wheel is not an insignificant amount of unsprung weight. I would carefully consider adding that much weight to my wheels, especially when it isn't going to do anything useful. |
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Where is the 2 kilos? Is it 2 kilos of free spinning masses inside a tube, which will have mass of its own, or is the entire construct 2 kilos? |
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I'd bone it once for each wheel if I could. |
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Yeah.. That was revision 1 which ended up just being dynamic wheel balancers that are commercially available already. |
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The revised idea is to place flywheels at each of the wheels. It's already being done in the engine to smooth out the power and assist starting. |
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I can't fishbone you twice, so what's left is to try to wrangle some sense out of your idea. |
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How does the energy get taken from the wheel and stored in the flywheel? How are the two connected? Is this supposed to be some kind of resonant coupling? 'Cause that won't work. |
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Real life intrudes. I'll be back. |
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The wheel hub is connected to the flywheel by a cvt/torque convertor. Same with the power train to the 4 flywheels. |
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When you accelerate the flywheel supplies the instant power needs giving the engine more time to replensish the flywheel. |
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When you want to slow down or brake the wheel dumps its energy back into the flywheel through the same cvt. |
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Not to different than the electrical flywheel generators except this is all mechanical, no magnets, motors, vacuum or energy conversions and associated losses. |
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The idea is to smooth out the peaks and valleys of driving so the engine can operate at averaged out rpm's. |
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So there is one cvt between each wheel and the "hub", right?
How thick is each unit and and how far would it cause each wheel to 'stick out'? Do they work the same with the drive wheels as with the non drive wheels? |
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Wheel mounts on Hub.
Hub connects to flywheel via CVT.
Flywheel connects to power train by CVT. |
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Guestimates:
Flywheel is 5KG and 100mm wide by 250mm rotates to 12000 RPM. One at each wheel - counter rotating. Begins drawing from engine at 6,000 rpm trying to maintain 8,000.
Flat pan shaped cvt. 100mm wide by 250mm) |
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When you step on the brake the torque convertor engages slowing down the wheel and speeding up the flywheel. When you accelerate the torque convertor speeds up the wheel drawing from the flywheel.
When coasting the flywheel draws from the engine enough to get back to 8000 rpm and whatever is required to maintain speed. |
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When road speed is low, performance cars may be traction-limited, rather than torque-limited with regard to achieving maximum acceleration. In this situation, your flywheel would not be of much use. |
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Also I think your CVTs are going to need some reasonably sophisticated control gear to get them working as you suggest. |
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Have made it for a bike for uni project with a flywheel, quasi-cvt and clutch but it was too heavy to be practical. Might work on a car but just as a single flywheel running off the main drive shaft. I was thinking it would be great for a train, just on a larger scale. |
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You're changing specs on the fly again. Now we're up to 5K, which is one heckuva lot more weight than I want to bolt onto my wheel. The truck rides rough enough as it is, and your Professor Steamhead concept isn't likely to improve matters. |
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100mm wide? My vehicle has room enough inside the wheel to make that fit, but that's because it's as sophisticated as a stone hammer. There aren't a lot of vehicles that can give up as much space as that within the wheel or the wheel well. Nor can many of them sacrifice that kind of space further inboard, on the shaft. |
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A torque converter is a lossy instrument and will not be your best choice for feeding energy from the wheel into the flywheel. Nor is it a good choice for getting the energy back out; in my experience torque converters - including the variator kind - function best when driven from one side only. |
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Mmm. Might have to spin a lot faster than twelve thousand revs for useable work output from 5kg - then stability becomes a factor. You also need room for brakes - other than the braking effect of the flywheel, and they already occupy the space inside the rim - almost fully at the front wheels on most cars. Electric system would be much better in all ways. |
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Wouldn't the wheels become deadly projectiles if they are dislodged in a car accident? |
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//Wouldn't the wheels become deadly projectiles if they are dislodged //
Yes [+]. |
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