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Old 02-24-2008, 01:25 PM   #11 (permalink)
trebuchet03
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Join Date: Dec 2007
Location: Bay Area
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The Miata - '01 Mazda MX-5 Miata
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Quote:
Originally Posted by basjoos View Post
I wonder how the efficiency of a series pneumatic hybrid would compare with that of a series electric hybrid. A series electric hybrid is of course a small IC engine driving a generator, feeding a battery, which powers an electric motor. A series pneumatic hybrid would be an small IC engine driving an air compressor, feeding a pressure tank (insulated to retain the heat of the compressed air), which powers an air motor. If the tank was well insulated, then the air motor's exhaust temperature should be close to the temperature of the air before it was compressed, thus almost eliminating one major cause of pneumatic system inefficiency. So you would have the weight of the compressed air tanks versus the weight of the batteries. Also the energy conversion efficiencies of the electric generator, electric motor, batteries, and voltage controller circuitry versus the efficiencies of the compressor, air motor, and heat loss from the air tanks and air lines.
In theory, the air powered variant wouldn't have battery wear. But I'm not sure how their tanks fatigue. On the same coin - the tanks are storing an incredible amount of energy that, in theory, could be quite dangerous in an accident compared to a non lithium battery...

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