Concept tire could charge electric cars.

"At the Geneva auto show, Goodyear shows off an intriguing concept tire that would feed an electric car's batteries while rolling down the road."

http://www.cnet.com/news/heat-gathering-concept-tire-charges-electric-cars-on-the-go/" onclick="window.open(this.href);return false;

Oh dear - here we go again with another round of perpetual motion machine advocates

Having looked into the whole 'piezoelectric' technology a while back (in context of wood stoves) I know the tech is valid, but like so many things the devil is in the details. Just how much of a temperature differential do tires experience really? I'd be surprised if they could generate much more power than required to light up the tires with LEDs. Never mind the cost/benefit analysis here...

Cute as this idea is (and I envy the engineers given the time to investigate this), I suspect that there is more to be gained in reducing rolling resistance (and thus actually less heat buildup) in tires than trying to capture this wasted energy.

LOL- What a sad PR grab for a useless concept. Did some engineer at Goodyear just buy an EV? How about a spare tire in the trunk that spins on corners and generates power. :roll:

Well, to be fair, I don't think Goodyear said it would fully charge the car or anything or anything..
Sounds like the C/Net story is hyping it a bit without any data..

The concept of reclaiming any lost energy is probably worthwhile to look at..

That said, I can't imagine we're talking any serious amounts of current here, and it's hard to imagine that the cost of the product would be worth the benefit, which I'm guessing would be tiny.

But effeciancy is effeciency I suppose.. ;-)

desiv

Any energy generated by such a tire would have to come from energy driving the tire that in turn generates the heat... Thus, at best, with 100% conversion efficiency, you would have a net of only a VERY small amount of electricity... It is still Fool's Gold IMHO!

desiv said:

Well, to be fair, I don't think Goodyear said it would fully charge the car or anything or anything..

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Shows how much you know! When the universe's total energy drops closer to zero, you'll be glad to reclaim as much as you can!

This will be around the same time Apple runs out of money.

TomT said:

Any energy generated by such a tire would have to come from energy driving the tire... Thus, at best, with 100% efficiency, you would have a net of zero!
It is Fool's Gold!

desiv said:

Well, to be fair, I don't think Goodyear said it would fully charge the car or anything or anything..

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Note I generally agree; however given how the piezo's work, they won't effectively increase drag (unlike the famous wind turbine on the roof). Rather they take advantage of temperature differences so if the rolling tire heats up (and they do) and you can then cool it through the piezo and generate current then you are in fact reclaiming energy that otherwise would have simply heated the air around the tire and was being made anyway. However it is still foolish.

TomT said:

Any energy generated by such a tire would have to come from energy driving the tire... Thus, at best, with 100% efficiency, you would have a net of zero!

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I think what they were saying, again the "article" was vague, is that this would reclaim heat that is normally being just "lost" as the car drives, for any tire. So this tire isn't "adding" more heat that it then reclaims.
If you can add tech that can funnel that lost heat back into energy, and IF the tech doesn't take more energy than you get reclaimed in the process, you could net some energy.
This isn't like putting a generator on the wheel, which adds more than it gains.
This is going after heat energy already in the process that is just lost, in theory.

However, as I said, even if it's possible that the tech is more effecient than the loss, I would expect it to be a VERY small amount of energy gained.

desiv

I prefer the magnet in front of the front bumper approach. Or the wind turbines on the roof. Throw in onboard self-sustaining electrolysis while you're at it.

All the energy used to push the car down the road eventually converts to heat.

Forcing air to move around your car requires energy because you need to push those little air molecules around, they eventually come to rest because of friction... which gives off heat.
The friction between the car tires and the road is the rolling resistance, the force to overcome that, converts to heat.

Now it's impossible to reclaim the vast majority of that heat and get it converted back to electricity, but it's not non-existent. Reclaiming some of it (like they're talking about here) does not mean you've made a perpetual motion machine either.

If its not about aerodynamics, increased battery capacity, or efficiency of the motor, then its not gonna be worth it. Even covering the roof with solar panels doesn't work from a cost benefit analysis perspective.

One semi-reasonable use for energy recovered from tire flexing would be to power those blasted TPMS sensors/transmitters

I'm surprised nobody is working on current-generating shock absorbers, seems like a better idea than these tires.

Valdemar said:

I'm surprised nobody is working on current-generating shock absorbers, seems like a better idea than these tires.

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Active suspension that could at least partially power itself.

Levenkay said:

...those blasted TPMS sensors/transmitters.

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Do you really not care how much pressure there is in your tire while driving :?:

Levenkay said:

One semi-reasonable use for energy recovered from tire flexing would be to power those blasted TPMS sensors/transmitters

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Hmm... that might be on the right level of current....

Valdemar said:

I'm surprised nobody is working on current-generating shock absorbers, seems like a better idea than these tires.

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I do believe I saw an article indicating this has been prototyped. There is a lot more energy to be gained from shocks than tires flexing - especially on rough roads I would imagine.

Not as helpful on the leaf but any ICE has TONS of waste heat in the radiator and exhaust, seems to me a lot less work for a lot higher temperature differential and the parts aren't spinning in circles

TimLee said:

Do you really not care how much pressure there is in your tire while driving :?:

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I care that there's enough pressure. I didn't care for the idea of an extra $60/wheel (hope I've remembered correctly) for the set of snow tires and wheels I bought. Maybe I'm not paying enough attention to the news, and just missed the coverage of the horrific accidents and death toll brought on by reckless underinflation, but I don't feel that these systems are so safety-critical that they deserve to be government-mandated. I also don't feel that inflation negligence affects anyone but the individuals who should be able to weigh the costs/benefits of the equipment.

Fortunately, I apparently squeaked under the regulations back in November 2011, and was able to decline having TPMSes installed in the snows I bought. When I'm running them, and ignoring the dashboard TPMS fault indicator, I fall back on the caveman techniques of noticing suspiciously long contact patches, irregularities in handling, extra-slithery tire noise, unusually poor displayed energy economy, and probing the sidewalls with a thumb. Oh, and using a pressure gauge.

Levenkay said:

...Maybe I'm not paying enough attention to the news, and just missed the coverage of the horrific accidents and death toll brought on by reckless underinflation, but I don't feel that these systems are so safety-critical that they deserve to be government-mandated. ...

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Several years back there were a major # of severe tire failures with a couple different brands of tires. A large portion of these were caused by underinflation.

You are correct that good drivers could probably manage safely without TPMS.

But unfortunately in the US the quality of driving has deteriorated to the point that less than 20% are good drivers.

I consider myself a good driver, but still like the convenience and improved safety of instantly knowing the pressure in all four tires.

Just unfortunate that Nissan failed to provide that and I had to buy Bluetooth adapter and LEAF Spy Pro to do it.

Back on topic, the concept of energy recovery from tire heat seems awfully expensive.
I hope that isn't government mandated :shock: