Quote:
Originally Posted by Ken Fry
In a plug in hybrid, like mine, there are lots of energy conversions. For the sake of simplicity, we'll say there are five processes. These can each be highly efficient: 95% .9^5 is 77%. They could each be OK: 80%: .8^5 is = 32% Big difference.
|
And this is the biggest problem with any type of "hybrid". Be it gas, diesel, A/C, or D/C. 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).
Gasoline (or diesel) is a condensed form of energy of which we are only able to extract 35-45% of its stored energy from the combustion engine depending on engine/fuel used. Then you convert that mechanical motion into electricity via a generator, which would at most be ~60-70% efficient (the most efficient that I have read about). This electrical energy would be somehow transferred to an electric motor which can be from 80-95% efficient. So like Ken said, but using high and low numbers, you have .45*.70*.95=.29925 and .35*.60*.80=.168
BEFORE losses in transfer (as opposed to conversion) you have a power plant that would be from 17-30% efficient. Losses in mechanical conversions/transfers are usually greater than electrical which is why hybrids do offer some improvement on mileage, but you can see where improvements can be made.