Quote:
Originally Posted by Ragnarok Warrior
In a Chevy Volt setup, where the engine only charges the battery pack, the engine can be run at its most efficient rpm and therefore the generator can be optimized to produce X voltage at Y amps at this rpm. This at current technology levels is probably the best solution. The problem lies in the conversion of energy from mechanical to electrical (and any other losses on the way).
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You have actually described the Zing setup (which is a strict series plugin hybrid) rather than the Volt setup which is a multi-mode hybrid that directly drives the wheels at times. The Volt architecture was changed (strangely to the chagrin of some EV enthusiasts) to improve the poor efficiency of the engine. Even with the 15% improvement gained by enabling direct-to-wheels drive at cruise speed, the gasoline-only fuel efficiency (37 mpg) is pretty poor if the benchmark is the Prius.
In the Zing, the engine either runs at full load or not at all, and driving force comes from the electric motor. Were it not for the hybridizing, the engine would vary in efficiency from 0% while idling to 5% at low load to 15% at moderate load, to 32% at full load, which would very rarely be used: there is no point in either the urban or highway drive sequence in which full power is required. The hybridizing allows for near doubling of fuel efficiency, despite the generator and motor losses (in my case each is 90% efficient). A bigger advantage, though, is that the fuel used most of the time is a small fraction of the price of gasoline -- and in most of the country is also cleaner from well to plug.
As you said the losses are large, but it is about the best we can do right now.
rid.