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New? electric car idea

  1. Feb 18, 2008 #1
    new? electric car idea...!!

    Hey guys,

    I dont have any formal education in engineering (yet :D) but i think i have had a reasonable (and original??) idea for powering electric cars and I was wondering if it could possibly work. Here goes...

    My idea is to have some sort of magnets in an area of the wheels of the car which is rotating. And then to have some sort of coil surrounding it so that as the wheel spins a current would be induced in the wire.

    I thought of this and wondered wether once the car gets moving (either through a combustion engine or electric etc.) would this current created bu the wheel movement be enough to keep the car running as an electric motor would.

    There are probably some HUGE flaws in this, was just wondering what anyone thought. If it wouldnt work could you tell me why? (there are probably heaps of reasons so pick a biggy lol)

    Thanks alot,
  2. jcsd
  3. Feb 18, 2008 #2
    I thought hybrid cars already do something like this. But I'm not sure.
  4. Feb 18, 2008 #3
    on really? Anyone else know if this is the case?
  5. Feb 18, 2008 #4


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    If you mean powering the car by an electric motor and driving the electric motor from a generator on the same wheel you are driving then this is a perpetual motion machine - good luck with that.

    what electirc and some hybrid cars do is called regenerative braking.
    Instead of using brakes to slow the car down (either because you are going down a hill or coming to stop) they run the motors as generators and put energy back into the battery. So the energy that would have been wasted as heat can be re-used.
    Because this slows the vehicle it should be obvious why you can't use this as the only source of power.
  6. Feb 18, 2008 #5
    Yeh ok I see, I didn't know that was what happened in hybrids. Meh nevermind.
  7. Feb 18, 2008 #6


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    Don't give up thinking about things just because that idea isn't Earthshaking. I doubt that any Science Advisor or Mentor on this site didn't do the same thing several times. You wouldn't believe some of the crap that I came up with in my younger years (and still do, once in a while). Keep up with the ideas; eventually, one of them will be great.
  8. Feb 18, 2008 #7


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    I thought you were going to go on about how your idea for a perpetual motion was different to all the others and would work!
  9. Feb 19, 2008 #8
    Danger: I won't don't worry haha. When I was younger I hadn't heard of the magrail (is that what its called?) and was really excited that id come up with something brilliant until my dad told me it already existed.

    Mgb_phys: I said i hadn't studied engineering yet, not that i was mentally retarded lol.

    Also how do you quote more than one person??
  10. Feb 19, 2008 #9


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    Then you might like to join in the many, 'plane takign off from a conveyor belt' discussions :approve:
    Don't worry most of us have brilliant ideas only to be told they are on page X of the catalogue.

    You can just copy the text and put it inside "["QUOTE"]" "["/QUOTE"]" boxes
  11. Feb 19, 2008 #10
    Dont get me started on the plane conveyor belt thing... God that's annoying. I tried explaining why it would take off to a friend for about an hour. Still don't know if he gets it lol.

    Thanks for the quote help :)
  12. Feb 21, 2008 #11
    Your talking about using the axles as the shaft essentially of the Generator? It would be like adding alternator/s along your shaft, so as your moving your generating a current. The thing is about generators, that they add load. So depending on the build of the Generator, it could be a great idea.

    The reverse part, would need to have a relay that disconnects the Generator while reversing, (unless generators still produce a current if they run opposite rotation?, I'm not sure actually lol)

    Also, if they brake, than you'd have to remove probably a few things (tires/brakes/hub/maybe upper/lower control arms/shocks/struts etc.

    If you guys read his post more thouroughly he said
    so Its not using the motor, and generator perpetual energy thought everybody has atleast once untill his 5th grade teacher drops a bomb on that little world and sends the poor kid back to the stone age.

    Its like I said, he wants to use a different means to rotate that little shaft on the alternator, pretty much (to grosely simplify it). I would say the axle is not the worst place for it eh?!
    Last edited: Feb 21, 2008
  13. Feb 21, 2008 #12
    about the perpetual motion thing... What i imagined this thing doing was keeping the car at constant speed, not accelerating. So i suppose you would use another meand of power aswell, but only to accelerate.

    I think this is probably still perpetual motion though (because of friction and air resistance ??) so i think it is still impossible?
  14. Feb 21, 2008 #13


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    I'm afraid so - friction is a real pain sometimes!

    The big win for electric hybrids is for short periods at low speeds or stop/start driving.
    This is especially good for large vehicles like buses and delivery trucks.
    Petrol/Diesel engines aren't very efficent at low speeds while an electric motor generates it's highest torque at zero speed - so you can use a smaller internal combustion engine and an electric motor for starting to move.
  15. Feb 22, 2008 #14
    just to add a bit more, when you put a coil around the axle to produce current, that current also produce a reactive force against the stator magnet, so you need to provide more energy to keep the axle(rotor) rotating, and only if working at 100% efficiency you ll get the same energy back which you put as extra at the first place. so finally the result is an over solved problem(which i usually do).
    but nevertheless, the fact that you thought of such things without studying about them is a great start. keep on
  16. Feb 26, 2008 #15
    Every car I've seen has 0% efficiency getting from point A and returning to point A. Some just use more gas doing it.
  17. Feb 27, 2008 #16


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    The idea of an electric car as a viable alternative to fossil fuels should be killed, unless there is a shown gain in total energy usage, no matter what scheme is forwarded, electricity still has to be generated to charge these electric vehicles, even recycling the waste from the batteries may be more environmentally costly if not energy costly.
  18. Feb 29, 2008 #17
    But Wolram, the Electric Car will be a very useful device, fulfilling an important emotional niche to the eager consumer.

    A recent and noteworthy commercial advertising a hybrid SUV indicates the importance among numerous consumers to be seen as dedicated to preserving the 'environment'.

    In this particular commercial, our hero quietly goes about his tasks, never advertising the fact that his car is a hybrid. This frees the buyer of these cars from the humiliating task of blatently advertising their moral superiority themselves, as the commercial has done it for them.

    They can safely maintain the myth that their actions are altruistic. Nothing is further from the truth, of course.

    It doen't matter if these devices preform any useful task--or are even more damaging --to the rest of humanity, only that they be perceived do so by the greaterunwashed, in the never-ending quest to be seen as superior.

    So how's your carbon footprint today?
  19. Mar 10, 2008 #18


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    Not so fast with the dagger, there are two fundamental reasons why E cars are theoretically far superior to current vehicles. (1)The electric motor is a very good method of producing mechanical energy, 90 -95% efficient, plus you can recapture braking energy once you've introduced a means of storing energy (batteries). The best any heat based engine can ever do is ~40%. Yes the energy has to come from somewhere but thats also the case w/ existing cars. The point is you get far more miles per unit of energy w/ the E car, aka miles per gallon for existing cars. (2) The pure electric car has zero emissions to the atmosphere. Again, there will be emissions at the central power plant if its fossil, but those can be made much more efficient than cars and can have ellaborate means to capture the emissions, or the fossil plant may eventually become a renewables based or nuclear plant thus zero emissions. All of the solid parts any car, batteries whatever, have to eventually be recycled regardless of the car type so thats really a wash.

    Problems: the battery technology is not quite there yet, and neither is the electric power generation and distribution required to run all E cars. Thus hybrids will be the way to go for sometime to come.
    Last edited: Mar 10, 2008
  20. Mar 10, 2008 #19
    Turbo disels are competative with hybrids in gas milage. I imagine this is true with or without all the many other tweeks used to hybrid manufactures improve milage. Regenerative braking is nearly useless. In designing an electric vehicle, I've found I can recapture about 5%--maybe. In my application it isn't worth the extra luggage. And all this tweaking comes at a cost. The market forces would be a much better indicator of overall usefullness after subtracting the legislative bias.

    Electric power distributed to your automobile by high tension wires from elsewhere is not as efficient as imagined. Great amounts of energy are lost in transmission and conversion. If cost is any indicator --and it should be if the environment of your friends, family, and community are included in your definition of "the environment", upon reciept it is less efficient than combustion. Ask anyone who has had the privilege of paying for an electric heating bill one winter and a gas bill the next in similar years.

    Let's talk about the "carbon foot print" the "environmental impact", and the fuel efficiency of automobile storage batteries. Maybe you can answer some key questions. What's their lifetime? What's their enviromental impact on mining, producing, and displosal or recycling? What's their 'carbon footpring' in fossile fuel to produce them from the mine to the consumer? How much of their true value is hidden by governmental interference?

    About the lifetime of these batteries. The auto dealers won't tell you what it is, or fewer would buy their cars. Sometime in the next couple of years, we will start getting these answers as they begin to fail. These things will cost a good chunk of change to replace. When the cost of replacement becomes better known the market, the resale value of the vehicle will plumet driving it's value toward scrap prices. What's the enviromental-impact-and-carbon-footprint on early retirement scrap?

    That's just the batteries. For all the gadgetry to make a hybrid vehicle fuel efficient, one can ask the same questions.

    Many of these question will apply to purely electric vehicles. As I've stated before, contemporarily it's really not important to the advocates that the answers to these questions wash-out in favor of electric powered vehicles or against, or the answers would be much more widely known. But what we find is the proponents don't really know the questions, let alone the answers. It seems more important to appear devout than be devout.

    -deCraig, student of contempory anthropology
  21. Mar 11, 2008 #20


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    Thats incorrect even now, and in the context of most electric cars to come w/ some hybrid backup its wildly incorrect.

    Wildly incorrect. Regen. braking is also used in trains purely because it makes economic sense to so.

    No. Power plants + E distribution is still more efficient than internal combustion.

    As I said above, the batteries are not quite there yet. They're close and with a little more improvement E cars and other types of E transportation are likely to take off.
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