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Non-Tech : Alternative energy -- Ignore unavailable to you. Want to Upgrade?

To: peter michaelson who wrote (4289)	2/19/2008 5:21:55 PM
From: Maurice Winn	Respond to of 16955

I forget just how I calculated it, but think of kinetic energy, engine efficiency [less than 30%], gearbox losses, engine size [say 100 kw], how much fuel is burned per 100 km and conversion losses in regenerative braking and returning it to the wheels again. I was thinking of what proportion of input energy in a normal car would be available if regenerative braking was added. If I remember rightly, it was something less than 5% and maybe about 2%. That doesn't justify a lot of capital, weight and complication on a vehicle. I get the impression some people think you can get most of the energy back which was put in. That's not so. Think of your own driving. If you go on a trip to San Francisco, how much time you spend on the brakes compared with the accelerator. On a trip around town, how much time is on the brakes versus on the accelerator, how much is idling at lights. On up and down hills, the amount of energy got back from going down is not much either - unless it's a pretty good hill, you'll still be using a bit of accelerator to go down the hill. With an electric vehicle, instead of engine compression doing some of the braking going downhill, at least that energy would be returned [something is better than nothing]. Mqurice