# Super Suspension?



## Vanquizor (Nov 17, 2009)

Regenerative suspension sounds promising, anyone have a copy of the SAE paper on it?

http://www.sae.org/technical/papers/2001-01-2071


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## neanderthal (Jul 24, 2008)

The suspension thing is a cool idea. But there is NO WAY it would provide that much extra range. There is some of the energy used for propulsion that goes into up and down motion that needs to be squelched by the suspension system, not not THAT much.

If the suspension were wasting enough energy to be potentially recovered to add THAT much range, then the shocks and or struts of an average car would be searing hot kust like the brakes. And they are not. Clever idea, but not something for a diyer to do cost effectively. And it wouldn't add much range.


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## neanderthal (Jul 24, 2008)

Unfortunately the worthwhile hub motors availible are about 35,000 usd each.


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## Pariastagard (Nov 8, 2009)

As I understand it, the suspension uses a magnetic type system to generate the electricity, vs a thermogenic type energy recovery system. That's why I pitched out the website, they were interviewed during an EVCast episode 135 I believe. The major problem with the company though is that they've mentioned producing the tech a year ago and now have not even moved the website further than a news article, which in itself looks old.

Morgan


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## Thaniel (May 25, 2008)

Pariastagard said:


> So I've done some research and heard some EVCasts mentioning various technology and I was wondering has anyone done any legwork on trying to figure out if some of these things are even possible/worth trying to incorporate?
> 
> 1. Regenerative suspensions: The idea is that going over bumps etc will create kinetic energy. That's true. Can you than harnes that energy? Seems like it should be possible, and not overly complicated for setting up. If you install it in your car, and hook it up to your batteries, I imagine it would function much like regenerative breaking.
> 
> ...


1. Regenerative susepension. Maybe for an OEM. DIY I don't see this as being practical. Cost benefit just not there. From what I have seen the bulk of DIY EV's don't even do regenerative braking and there'd be more energy to capture doing that.

2. The hub motors will suffer from the same issue as direct drive (no trans) with a differential. Missing out on the advantages of mechanical torque multiplication of a transmission. Hub motors are cool it isn't the most cost effective efficient way of acomplishing an EV. Especially in a DIY EV. The controller would also have to compensate for the different wheel speeds as you mentioned. More $ in controller if trying to buy one. If making the controller from scratch then I dunno.

3. Could be a good thing. I've seen some on this site messing with super capaciters. Tied to regen might be quite the thing. I may investigate adding regen braking and caps to mine after it is driving.


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## John (Sep 11, 2007)

Pariastagard said:


> 1. Regenerative suspensions: The idea is that going over bumps etc will create kinetic energy. That's true. Can you than harnes that energy? Seems like it should be possible, and not overly complicated for setting up. If you install it in your car, and hook it up to your batteries, I imagine it would function much like regenerative breaking.


Energy can neither be created or destroyed (unless you’re talking about nuclear physics) but can be transformed from one form to another. The energy absorbed by your shock absorbers comes from the forward motion of the vehicle or the vehicles kinetic energy and in a regular suspension is transformed into heat in the oil in the shock absorber and noise. I think the energy absorbed by the shock absorber would be very small. Its purpose is to prevent the suspension springs from accumulating energy. I wonder if a better scheme rather than taking energy leaking from the vehicles forward momentum and trying to return it via a relatively inefficient system might be to prevent the energy leakage in the first place.


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## order99 (Sep 8, 2008)

I have seen a suspension generator or two-sadly, they were all on bicycles, and generated just enough power to keep a few tiny cells charged. It was enough to keep the LED lights going without the drag of a rim Dynamo, but (for reasons previously posted above) I doubt the tech would scale up.


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## John (Sep 11, 2007)

One of the ways of keeping your energy bleed via the suspension to a minimum while retaining a pasive suspension system would be to keep your unsrung weight as low as posible. This is unfortunately at odds with using hub motors.


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## colombo (Nov 27, 2009)

New here so if I step on any toes please forgive me. That said I think you might be looking in the wrong direction on the suspension issue, why not valve it for hydraulics to an accumulator for boosting starts. This could be tied into an accumulator system for the braking too.
As for the hub motors, has anyone messed with converted conventional front wheel drive donors?
How about a converted live axle for a dual hub drive? Seems like an easy design/mod.


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## dataman19 (Oct 7, 2009)

Regenerative suspension? Neat idea.. But wouldn't you have to tool around on a lot of really bumpy roads???...
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I'm kinda a smooth road kinda tooler -so I wouldn't get much out of it, especially since I tend to drive around things like pot holes, etc.
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Pancake motors are only expensive because no one is mass producing them. We contacted several companies and got the brush off - since we are a start-up, they want us to make motors for like ten years before they give us a whack at making "their" motors.. Dah, If we were already proding the Pancake motors - why would we want to make theirs (kinda like the chicken vs the egg argument)..
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Back to regen suspension...
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So a moving magnets sleeve on the shock piston that slides up and down through a coil that is connected to a battery operated semiconductor capacitor/multiplier should do the trick...
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Think this is far fetched? Remember the "Space Aged" shaking flash light? You know the one that you shook and then got light from. It actually used a coin-cell battery that was connected to a capacitor multiplier circuit that was ballanced by a coil in the handle.
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When the magnetic piston moved up and down through the coil the reference battery provided the kick start and the capacitor multiplier stored the milliamps to supply power to the LED lamp.
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So would not the same basic arrangement not work for regen suspension?
...
dataman19
..


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## John (Sep 11, 2007)

The energy absorbed by the suspension comes from the forward inertia of the vehicle. When you hit a pot hole or a bump in the road, the car is slowed ever so slightly. Say the regenerator on the suspension is 90% efficient, battery charge recovery 90% efficient, motor controller and cables 95% efficient and electric motor 85% efficient, you would still only be returning about 65% of the energy absorbed from the vehicles forward inertia to the vehicles forward inertia via the system. Energy you can prevent the suspension from absorbing is equivalent to a 100% return. So minimisation should be the first action then consider the worth of applying the principle for the recovery of what cannot be prevented.


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