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This one is for all the fans of the Piezoelectric effect.
Replace some of the cords in radial tires currently made from materials like nylon, rayon, Kevlar with PVF2, a piezo polymer. The streching and deforming of the cords as the tire rolls, especially at the contact patch, will generate a voltage.
Goodyear BHO3 concept tire
http://www.gizmag.c...lectric-tire/36548/ "lined with a fishnet pattern of thermo/piezoelectric material. This net turns the heat into electrical current, and its piezoelectric properties also allow it to harvest energy from the tire as it deforms during driving. To keep the tire from overheating, there's also a cooling system in the sidewalls." [jutta, Mar 25 2015]
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"This one is for all the fans of the
Piezoelectric effect."
i imagine it would have to be. I don't think
this would generate enough power to
make it worthwhile. |
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Can you make the tires light up at night? |
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Can fans run on piezoelectricity? |
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Where would the energy be stored? In the wheel? That axle? |
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Apparently is does nothing, just generates a voltage. |
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I'd hope this would generate electricity, rather than just a voltage. |
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You could then store it in a battery in the hubcaps... and use them to power your home when you get back! |
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Hmm, is it time to calculate the hamsterpower quotient on this idea... |
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In general, obtaining energy from a powered machine is inherently inefficient. The laws of entropy, as exemplefied in friction especially tend to mean that the energy gotten back from the machine will be matched, or exeeded by increased energy requirements from the machine, which now needs to not only do it's job, but also needs to power an energy harvesting apparatus. |
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Would be useful for powering tire-mounted or wheel-mounted electrical devices (like spoke LEDs) without requiring either batteries or a hub mounted rotating electrical connector. |
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//In general, obtaining energy from a powered machine
is inherently inefficient. The laws of entropy, as
exemplefied in friction especially tend to mean that the
energy gotten back from the machine will be matched, or
exeeded by increased energy requirements from the
machine, which now needs to not only do it's job, but also
needs to power an energy harvesting apparatus.// |
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If the recovered energy comes from the primary action of
the machine, then it is true. However, if the recovered
energy can be taken from energy that is already wasted
by the machine, then it can be efficient. In most cases,
however, it is better to try to reduce the waste energy.
In the case of car tires, specifically, there are
compromises between the lowest possible rolling
resistance, traction, and the smoothness of the ride (and
the resulting ability to ride on something not as smooth
as steel rails). As a result, there is potentially
recoverable energy here. |
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The problem is that most waste energy is low quality,
giving you a very limited ability to recover it.
The criteria on whether it is actually feasible is based on
the energy budget. Is the cost of manufacture, plus the
cost to carry around whatever extra components are
involved, less than the total energy recovered over the
life time of the device. In this case, I would be surprised
if the answer is yes. |
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Also relevant is whether you can actually recover the
energy without putting an additional load on the system.
In this case, I believe the answer is yes, because any
change in stiffness from the generating mechanism can
be offset by choosing a more or less flexible tire material.
Once again this is possible because tires are floating
between multiple requirements, so not already at the
most energy efficient extreme. Doing the same on train
wheels, for instance, is unlikely to be possible, because
the resulting piezo composite would be less stiff (and
thus less efficient) than the plain steel wheels). |
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(And yes, I realize that I am 9 years late, and this was
bumped to post someone actually doing it, but there's a
lot of slip between a concept car, or tire in this case, and
it actually entering production). |
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Correct in general MechE, but I'd say in this case
the answer would be no. I'm assuming that the
PVF2 cords are less perfect springs than other
materials that might be used since when
stretched, some of the energy is converted to
electricity rather than being useful to spring he
tire back into shape. Now it the nylon or
whatever lost the same amount of energy to heat
that PVF2 converts to electricity, then this would
be a definite yes. |
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Then you offset it with a slightly stiffer rubber, if the net
flex and recovery of the tire is the same, the total energy
lost is the same. |
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way easier to do thins in the dampers of the suspension
system... Shirley? |
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Yes, but it's very different energy you're trying to recover. |
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