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New Concept Tire Could Recharge Car Battery
randomErr writes Goodyear Tire showed off its new BH03 tire that can partially recharge your electric car while driving. At the 2015 Geneva International Motor Show a new concept tire was displayed that uses heat generated while driving and converts the thermal energy to electrical power. The triple inner tube design changes pressure to maximize electrical output while adjusting to the road conditions.
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Rats.
I have to assume that any actual engineers at Ford understand Carnot efficiency, and that this is simply an effort on the part of marketing to generate social-media buzz. It's depressing, but not surprising, to see that they're succeeding.
exactly
it's better to decrease inefficiencies in a simplified system than devise complex add-on contraptions that purport to recycle lost energy, but it's so fractional, it doesn't even make up for it's own extra weight, it's own extra cost, it's own extra maintenance
it stinks of rube goldberg perpetual motion machine
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
It will never work. It's not 3D printed, using the internet of things, or an Elon Musk company. How can it expect to succeed?
I realize this "tech" is designed for electric vehicles but if you had the ability to convert heat into a meaningful electrical source you would start with the exhaust system of a standard car and do away with the alternator. If they can't do something with that rather significant and easily accessible temperature differential (+300F) I am pretty dubious about them utilizing the relatively minor temperature differential (~30F) of tires.
A theory that ignores friction isn't especially interesting in this context.
Rolling friction is a pretty small contributor to energy loss for a moving car. Of this initially small amount of lost energy, some heats the road, and some heats the tire. As someone else observed below, the change in tire temperature is typically around 30 F, or 15-20 C, much less than a 10% change in absolute temperature. That means that a perfectly efficient heat engine could reclaim at most 10% of the thermal energy from the warm tires. In practice, the efficiency would be lower still.
Here's an infographic breaking down energy loss for an internal-combustion vehicle. Even if we assume that the electric vehicle has zero engine loss, rolling friction still represents at most maybe 20% of your energy loss. That means that you'd be reclaiming less than 2% of your total lost energy. In practice, considering the efficiency of the recapturing engine, it would probably be well under 1%; considering the added weight and mechanical loads of the recapture equipment, you might well end up losing net efficiency.
I'm not an engineer, but I have a basic understanding of thermodynamics. This story appears to be pitched at people who don't. If the engineers behind this want to convince people who know anything about physics or engineering, they're going to need something a lot better than this press release.
it's so fractional, it doesn't even make up for it's own extra weight, it's own extra cost, it's own extra maintenance
Or its own extra apostrophes.