The Electric Car
in [Design]
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From: Richard Henry on 29 Jul 2007 13:14 On Jul 28, 5:10 pm, Eeyore <rabbitsfriendsandrelati...(a)hotmail.com> wrote: > > Oil's not running out. Where do you get your data?
From: Eeyore on 29 Jul 2007 14:07 Richard Henry wrote: > Eeyore wrote: > > > > Oil's not running out. > > Where do you get your data? It's all over the place. Whay may be running out is CHEAP oil. Oil shales are already being touted as being close to being economically viable. Graham
From: Nobody on 29 Jul 2007 21:49 On Sat, 28 Jul 2007 20:50:22 -0700, gyansorova wrote: >> Realistically, we aren't going to see electric vehicles becoming >> widespread until battery (or equivalent energy storage) technology >> improves. > Well from what I have read they already are pretty good - 250 miles on > one charge. That's not bad. Better acceleration than a Porsche. But at what speed? Energy = Force * Distance, so the more force, the more energy required. At anything much above jogging speed, air resistance dominates, and that's proportional to the square of the speed. IOW, for urban driving, electricity has everything in its favour. For long distances on fast roads, the only way an electric vehicle is going to be viable at present is to include a combustion-driven generator. Using a generator to drive an "electric" vehicle isn't necessarily as crazy is it may sound. An electric drivetrain with a generator running at constant speed/load could conceivably be more efficient than a mechanical drivetrain and the need for the engine to have a wide operating range.
From: Eeyore on 29 Jul 2007 22:05 Nobody wrote: > On Sat, 28 Jul 2007 20:50:22 -0700, gyansorova wrote: > > >> Realistically, we aren't going to see electric vehicles becoming > >> widespread until battery (or equivalent energy storage) technology > >> improves. > > > Well from what I have read they already are pretty good - 250 miles on > > one charge. That's not bad. Better acceleration than a Porsche. > > But at what speed? Energy = Force * Distance, so the more force, the more > energy required. At anything much above jogging speed, air resistance > dominates, and that's proportional to the square of the speed. > > IOW, for urban driving, electricity has everything in its favour. For long > distances on fast roads, the only way an electric vehicle is going to be > viable at present is to include a combustion-driven generator. That's a hybrid. The *series* hybrid doesn't attempt to do any fancy mechanical combining of traction power from an ICE with the electric motor and simply uses the ICE to recharge the battery, thus making it much simpler than a parallel hybrid. > Using a generator to drive an "electric" vehicle isn't necessarily as > crazy is it may sound. An electric drivetrain with a generator running at > constant speed/load could conceivably be more efficient than a mechanical > drivetrain and the need for the engine to have a wide operating range. In a series hybrid, the ICE can always run at optimum efficiency (rpm), which it doesn't in today's ordinary cars. Also, overall system efficiency is improved by the use of regenerative braking. Plus, of course, with a series hybrid, you don't need to use the ICE at all for short journeys. It seems to have all the right cards in its hand. OTOH, are they even necessasry ? Graham
From: Nobody on 29 Jul 2007 22:17
On Sun, 29 Jul 2007 16:43:29 +0100, Eeyore wrote: > Consider the impact on the environment of > scrapping/recycling all those batteries every few years as well. Which? Scrapping or recycling? Any battery large enough to power a car for 250 miles is bound to get recycled. The only reason anyone would consider the possibility of large batteries being routinely scrapped is if they are intentionally trying to make the figures look bad. |