Engineering question regarding hybrid cars -
August 20, 2008 11:34pm CST
I am not an engineer, so I hope one can answer this. My understanding is that the current hybrid is basically an electric car, that has a gasoline or other oil-based fuel motor to run a generator when the battery goes out, or is about to go out, to recharge the battery. At least that is how Chevrolet models are doing it. My question is why isn't the rotation of the wheel axles not being used to recharge the battery? When using a car, that is the one moving part that is mostly in motion, why couldn't that be converted to electricity? I heard one other model recharges the battery by applying the brakes which seems kind of silly to me - if you are on the highway driving correctly, why are you using your brakes that much? (I guess rush hour traffic would be the exception, but when I drove I avoided that as much as I could - it was easy because I worked graveyard shifts (approximately 12 midnight to 8AM) The only thing I can think of is that the axle is not rotating fast enough, and accelerating it for the generator would take too much energy. Is that the case? Thank you.
21 Aug 08
interesting how energy that was being taken for granted before is a major interest in design of energy efficient cars. Perhaps there is extra: extra mechanical energy that may be "salvaged" and stored in batteries : e.g. - when running on ignited fuel - braking from fast speed - braking during downhill stretches extra electrical energy from solar panels when electrical consumption is low. Perhaps a computer would "smartly" engage a generator at specific times of deceleration. Perhaps the question is "how cost efficient" would the resulting car be (considering the amount of extra energy derived?). I am not a mechanical engineer. 'hope to hear from others too. Cheers :)
3 Sep 08
hi, there, i am amechanical engg and have presented a seminar on regenerative braking systems,when i came to know about using the braking energy, i too had the same query, why is a generator not coupled when directly in motion,i tried to fin this out and got the answer finally. when u run an engine and load up ur vehicle u can definitely observe that there is more consumption of fuel,the answer lies here..in a similar manner when anextra load is given on the engine fuel cosumption increases drastically resulting in no extra energy, but also there is loss in efficiency, when braking all the energy is goin waste as heat and friction so it is the time when waste energy is used up. i have presented a paper to use the exhasut gas heat to do so and hence efficiency can be increased by removin the alternator coupled to the engine. i hope this would help