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This could be used on electric or hybrid vehicles (or normal vehicles) to capture energy which would otherwise be absorbed and wasted, and then convert it into electricity.
There are a few ways this could be done, so I will say all that I think of; One way is to put a linear generator in the center
of a coiled spring for each of the vehicle's wheels. Another way is to use a hydraulic piston which turns a small pump connected to a generator with a shaft that can freely rotate in one direction, but turns the generator in the other direction. Or another way would include a rack which is in the center of a coiled spring, and a pinion at the top which turns the generator.
If you drive on bumpy roads or speed bumps or dips or any environment that uses the suspension a lot, then this suspension is more useful than if you don't.
The suspension could also be used to control the ride hight, and possibly hardness.
Bose Suspension System
http://www.bose.com...on.jsp&src=PRJCTSND
[BJS, Feb 25 2007]
(?) Linear Generator
http://www.physorg.com/news4142.html
Like this thing? [quantum_flux, Feb 26 2007]
Electromagnetic Linear Generator and Shock Absorber
http://www.wipo.int...091552&DISPLAY=DESC
This one is more than half-baked [skipperjohn, Jun 04 2007]
Magneto rheological shock absorber
http://en.wikipedia..._rheological_damper
[BJS, Jan 06 2008]
Magnetic Ride Control
http://www.gmcanada...rc/video_en_CA.html
It uses magnetic fluid. [BJS, Jan 12 2008]
[link]
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already baked, atleast with the linear generator concept....look up the Bose suspension system:
www.bose.com/suspension |
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Okay, but they use their suspension system only for handling, and not for the generation of usable electricity. |
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the only problem I see is that the velocity of the change in length would effect the output voltage of the generator so you would have to have a very sophisticated voltage control system to generate usable power. |
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There is a part on the Bose page about using the motors as generators to lower power consumption, but it could be possible to implement the generator setup without all of the active handling stuff to just generate power. |
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This would be a form of regenerative breaking since it would slow you down since your wheels would not push down as hard on the downhill side of a bump as they did on the uphill side. Combine them and you are probably back where you started. It doesn't add anything. |
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Furthermore you would either feel the bumps more or have the tires meet the pavement less or necessarily a combination of the two. If you don't mind defeating the purpose of suspension on a car that is fine. I don't buy that it would otherwise be absorbed or wasted. It is already used to grip the road. Unless you are just going to store the charge in a capacitor and use it to push the tire back down to the pavement I don't think I want a ride. |
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I was however imagining this very thing for predictable bumps like Orion style spaceships with Nuclear bomb propulsion. Energy is wasted purposefully in deformation of the ship that could have otherwise went into propuslion. If the ship was stiffer the plate would have not yielded as much and would have better bounced the propellant backwards faster. Your idea is fine in the proper context. The suspension does not recover nearly as fast as it was compressed, if you are okay with that then you have found a place for the concept. |
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I may be talking bollocks, but my
understanding is that a suspension
system is basically a spring and a
damper. Any energy wastage must be
going on in the damper (assuming that
the spring is reasonable Hookeian). |
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So, question 1 - do the dampers on a
regular car get very, very, very hot after
a short drive? Because however much
heat they are dissipating, that is the
amount of energy you have available to
recover. My guess is that it is bugger
all. |
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MercuryNotMars, I don't think you understand that the generator would only resist the compression of the suspension to generate electricity, and it would not resist the extension of the suspension or generate any electricity from extending. The spring will press the wheel back down and lift the vehicle as normal. |
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//as normal//... There is probably some dampening to prevent harmonic resonance or something but that is all that is available without slowing down the car and not gripping the road. |
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I didn't say that I don't beleive you can maintain height |
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I am imagining a spring that will maintain an equilibrium height. When it goes up you will be slowing compression of the springs to generate electricity. If you want to maintain the amount of travel per force then you will have to have a loosen spring that changes compression less with distance. It will then have less power to push out and if you try to generate electricity off of the force of the spring pushing the car back to equilibrium you will have less force in the spring plus it will be slower still coming down because you are sapping energy from a compressed spring with less energy per distance of travel. |
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The speed in which it goes up and the speed it comes down will have an even greater spread the more energy you try to recover from them. |
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You will have a car that gets lower to the ground when it travels over bumps without translating into forward movement, when you need more clearance. You will have a vehicle that does not put pressure on the ground as evenly and may not steer at critical moments. |
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//that is the amount of energy you have available to recover// Sonotori desu yo! the damper is where you are allowed to find your energy. You are treading on safety issues it is not just a comfort issue. |
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If you want to make a car more efficient only, get rid of the dampers all together as long as you are out of resonance you should be better off. Your niche is small, and It cannot be expanded. |
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//Sonotori desu yo!// que? |
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All the "bad effects" you are describing are actually considered desireable in a shock absorber, [Murcury]. It's not a very large force required to move a linear generator in comparison to the force available in a spring holding up a 2 ton car. Have you ever tried to quickly compress a car's shock absorber? It's fairly stiff and resistant to motion, so by your reasoning, installing a set of shocks on a car would effectively render it useless, but in fact, the opposite is true. These generator shocks (that's effectively what they are) could potentially benefit the suspension system, just the same as a quality set of shocks does.
And there is some heat dissipated, but in all actuality, its most likely not enoguh energy to really make it worth it on anything other than hard-core desert race buggies or something. |
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all the bad effects I am discribing are considered desirable and if what I was saying was true then installing shocks on a car would render it useless? |
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I suggest you quote me and tell me what bad effects you are talking about are desirable. One bad effect that I discribed is //You will have a vehicle that does not put pressure on the ground as evenly and may not steer at critical moments. // Which shall I assume All was an exaggeration or possibly that you think not being able to steer at critical moments is good? |
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I suggest you tell me what line of reasoning I have used says that installing shocks on a car would render it useless. |
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I suggest that you demonstrate for us that you can read. I prefer thourough criticism. If you remove dampening and not springs from the suspension system, and we are talking about the same thing, then yes. As long as you avoid resonance you are better off without dampeners for your gas mileage. I am left feeling like you put words in my mouth and you took a lazy approach to a conversation stating that we disagree but without much in the way of specifics. |
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Hey [MercuryNotMars] , in Either Dan Simmons Olympos or Ilium novel (who remembers) they fly in a nuclear bomb powered ship equipped as you describe. |
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Each detonation compresses huge pistons, and they smoothly release the energy to give a constant 1 gravity of acceleration. |
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Look up Orion Project. Also what I am discribing is not a constant 1 G accelleration for the passengers though it might be much smoother. You might be able to make it constant if you give up on trying to generate electricity. |
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//I am imagining a spring that will maintain an equilibrium height. When it goes up you will be slowing compression of the springs to generate electricity. If you want to maintain the amount of travel per force then you will have to have a loosen spring that changes compression less with distance. It will then have less power to push out and if you try to generate electricity off of the force of the spring pushing the car back to equilibrium you will have less force in the spring plus it will be slower still coming down because you are sapping energy from a compressed spring with less energy per distance of travel.// |
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(That's why I didn't quote you the first time. It was more of a general thing that could not be summarized by one brief statement.) You described the effects of dampening a suspension spring. These generators replace the shocks, which dampen motion in automobile suspension systems. So if these will render a car useless, |
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//You will have a vehicle that does not put pressure on the ground as evenly and may not steer at critical moments.// |
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would also result from having regular shocks on the car. As we all know, shocks improve ride quality, grip, and handling, so obviously the effects of slowing down the spring's motion are not as bad as you make them out to be, or carmakers wouldn't be putting shocks on every vehicle they make. |
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[mercury], try removing one or all of the shock on your car: it's really quite simple, and will be very educational. Especially if your car has fairly active suspension say coil or torsional (leaf springs are to some degree self-dampening). |
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From an engineering perspective, the responses for undampened suspension setups are shocking. And as someone who has lost (blown) 3 shockies on my vehicle on a trip once; you can drive without shockies <briefly>, but handling, braking efficiency, and ride stability all go out the window. |
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Unless the road you're travelling on is particularly bumpy, or you're throwing the vehicle around a lot (as in rally/race driving), the energy dissipated in the dampening system is quite minimal, and the shockies may not even get appreciatively hot. Switch to a corrugated dirt track and a heavily loaded vehicle, and you can boil the oil in the shockies within an hour very easily. |
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With that in mind, I don't think you're going to make any significant energy savings by tapping the dampening energy of the average car. Off-road vehicles, maybe, but fuel efficiency is rarely more important than handling in those conditions anyway. |
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however, the statement //If you want to make a car more efficient only, get rid of the dampers all together as long as you are out of resonance you should be better off.// Is, whilst essentially true (as in the shock absorbers do essentially absorb drive energy), they are absorbing the component orthogonal to the direction of travel, and thus are not, to any significant degree, lowering fuel efficiency. |
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yes they do. When you go up a hill you loose speed. when you go down a hill you gain speed. On average that is what springs do with bumps. If you wait until after you get off the downhill side of a bump to release you have lost your opportunity to gain back forward motion from the energy pent up in springs. |
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Maxwell summed it up perfectly: //do the dampers on a regular car get very, very, very hot after a short drive? Because however much heat they are dissipating, that is the amount of energy you have available to recover.// |
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You cannot and don't want to take any more than you need for dampening. There is a balance that cars already have. That defines the usefulness of this idea.
The statement that you appear to be disagreeing with simply define this limit. |
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Shocks are not all dampening. it also contains a form of a spring. Your car was designed to work with those. Whether you were acheiving an unstable resonance or whether you did not have a necessary spring component as well I cannot say and I do not care either way it doesn't contradict what I said. |
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I think it will work. it is a matter of getting the right linier generator that will match up in damping with the hygraulic shocker and the necessary cuircuitry to convert it to a continuous current flow. Some amount of displacement happens all the time however smooth the road |
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To repeat (tediously): //do the dampers
on a regular car get very, very, very hot
after a short drive? Because however
much heat they are dissipating, that is
the amount of energy you have
available to recover. My guess is that it
is bugger all.// |
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There is a simple way to decide if this is
remotely worthwhale or not, and that is
to ask how much energy is available for
recovery. *Then*, if it's worthwhile, you
can figure out how to do it efficiently.
But just wittering on about damping
and control and linear generators
doesn't really get anywhere unless you
ask the simple question first. |
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[Maxwell] "do the dampers on a regular car get very, very, very hot after a short drive" |
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Depends how uneven the surface you're driving on is. Real off-road vehicles have beefier dampers for precisely this reason - some modern pseudo-offroaders don't, and do indeed suffer from overheated dampers rather easily if you actually use them off road for any significant distance. |
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Ordinary cars driven fast on roughish roads also often suffer from failed dampers through overheating. They're designed to fade without damage (when they're hot, they stop absorbing energy, so you bounce more) but they can't stand it forever. |
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(Incidentally, this is one of the big problems with the Orion spacecraft concept: the huge dampers would overheat. Dumping heat to atmosphere is all very well when you're in an atmosphere. They never did test the dampers, and the proposal was to test them on the ground anyway. Ooops!) |
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