I've read that the Toyota Prius uses a combustion engine to charge the battery for its electric engine, but is it possible to use the motion of the cars wheels, once it is running, to charge the battery instead. It would require a lot less gasoline in the long run. Wouldn't it? I've never taken a physics class, so maybe this isn't even possible. I don't know. What do you guys think?
2006-09-06 05:54:32 · 18 answers · asked by Billy 3 in Science & Mathematics ➔ Engineering
Yes, it is called "regenerative braking." The idea is that you use Faraday's law which says when you move two magnets past each other you generate current.
The main obstacle to implementing such a system is that it adds much more cost than the already mature braking technology. Once you generate the electricity you have to control it and store it back into batteries, which will be much more efficient in the coming years.
2006-09-06 06:00:17 · answer #1 · answered by phosphoricx3 2 · 2⤊ 0⤋
Depends, but if the battery is in good condition and the radio is the stock unit, then you can listen to the radio for literally hours before you drain the battery. There will be some drain on the battery, but if you're only talking about a time frame of an hour or two, then the drain will be negligible. With said, if the car has a high end aftermarket audio setup with a couple amps and sub woofers and such, then the battery can be drained much more quickly.
2016-03-27 00:21:24 · answer #2 · answered by Jeanne 4 · 0⤊ 0⤋
In the Prius, the electrical power stored in the hybrid battery comes both from excess energy from the gasoline engine working as a generator, and also from regenerative braking.
(Pretty much all production hybrids use regenerative braking, as do some EVs.)
Quoting from http://auto.howstuffworks.com/hybrid-car1.htm
[quote]To squeeze every last mile out of a gallon of gasoline, a hybrid car can:
Recover energy and store it in the battery - Whenever you step on the brake pedal in your car, you are removing energy from the car. The faster a car is going, the more kinetic energy it has. The brakes of a car remove this energy and dissipate it in the form of heat. A hybrid car can capture some of this energy and store it in the battery to use later. It does this by using "regenerative braking." That is, instead of just using the brakes to stop the car, the electric motor that drives the hybrid can also slow the car. In this mode, the electric motor acts as a generator and charges the batteries while the car is slowing down.[/quote]
If you have to brake or coast to slow down, then why not recapture some of that kinetic energy for use later? It's better than throwing it all away as heat in brake pads. But, you shouldn't drive such that you have to brake a lot, as that will only waste energy in any car, even in a car equipped with regenerative braking (as regenerative braking isn't 100% efficient in recapturing all the spent forward energy).
More info:
http://www.motorage.com/motorage/article/articleDetail.jsp?id=68244
http://www.hybridcars.com/renerative-braking.html
http://www.rmi.org/sitepages/pid433.php
http://en.wikipedia.org/wiki/Regenerative_braking
2006-09-06 08:51:33 · answer #3 · answered by mrvadeboncoeur 7 · 2⤊ 0⤋
Think of the conservation of energy as something more intuitively obvious. On idea is to think of it like water or some magical which has constant volume, and associate the volume with the energy.
If you put the magical liquid (energy) into the car. You put it in the engine, transmission, air-condition everything. When that thing produces entropy, some of the liquid disappears.
When the car is driving the energy is pumped out of the car through the tires to get acceleration and turning, and through the body to part the wind, and resist cross-winds.
If you pump the liquid into the car to make it go, then after it has driven for a while, you soak all the liquid out of the car, there is a lot less. Some has been lost to the air-conditioner (about 5mpg on a conventional ICE car). Some has been lost to friction in the transmission, friction inside the rubber material of tires, friction against the aerodynamic body. Also, your pump that extracts energy, it requires energy to work.
There is something called "regenerative breaking" that can put about 40% of the kinetic energy of the car through the breaking process back into the battery.
You never get more out than you put in. Its a constant energy process. Of the five laws that have never in all the history of science been observed to be broken, one is the conservation of energy. Energy is neither created, nor destroyed, although through entropy it can be made inaccessible.
2006-09-06 06:04:25 · answer #4 · answered by Curly 6 · 2⤊ 0⤋
The Prius and the Civid hybrids both use regenerative braking, where some of the forward momentum is diverted back to the transmission to charge the battery. In a normal car, the energy is lost as heat through the brake pads.
2006-09-06 06:02:40 · answer #5 · answered by Anonymous · 1⤊ 0⤋
It should be possible. What you describe sounds very much like the generators used to power headlights on bicycles. What you need to remember is that with the wheels turning a generator when the car is in motion, it will take that much more energy to put the car in motion and keep it at speed. This because of the drag the generator will be putting on the wheels. (It will have some braking effect.)
2006-09-06 05:59:20 · answer #6 · answered by danl747 5 · 2⤊ 0⤋
My understanding of the Prius is that the gasoline engine propels the car forward and the kinetic energy generated is harvested when the car is slowing down. It's this energy, not the energy created directly by the gasoline motor, that is stored in batteries.
2006-09-06 06:05:08 · answer #7 · answered by Oh Boy! 5 · 1⤊ 0⤋
there are 2 ways to do it:
a car with electric drive - electric motors at each of the wheels can recycle braking energy by turning the wheel motors to generators that break the car and charge batteries, there are delivery trucks and buses like this in Europe.
A car with a regular drive and a electric motor attached to 1 or all of it's wheels can generate electric energy to charge batteries, but that is wasteful, it is much more efficient to attach the generator to the combustion engine
2006-09-06 06:04:42 · answer #8 · answered by Anonymous · 1⤊ 0⤋
Some of the energy efficient cars use the wheel revolution to recharge the battery while you are stopping. It drains kinetic (motion) energy and makes the stop quicker while refilling the battery.
If you think that you can continuously use the wheels motion to drive the car instead of using fuel then you are talking an impossible perpetual motion machine.
2006-09-06 05:58:46 · answer #9 · answered by Rich Z 7 · 2⤊ 0⤋
There's a law of physics - the "law of conservation of energy", which says you can't get more out of a system than you put into it.
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In an electric vehicle, it's energy from the batteries that spins the wheels. If you pull energy back out of the wheels, they slow down, and you put the exact same energy back into the batteries.
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But this does work, and it is the principle behind regenerative braking. Instead of applying conventional brakes, electrical energy is pulled from the wheels, which makes the car stop
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What you can't do is pull energy from the wheels without making them slow down.
2006-09-06 07:10:20 · answer #10 · answered by apeweek 6 · 1⤊ 0⤋