In hybrid electrics, I've found examples of:
- electric power <<< engine power - examples are GM's and other autostop, BAS, systems, ~5 hp EV vs. ~170 hp ICE. These are 'greenwash' systems such as the Chevy Malibu.
- electric power torque assist << engine power - examples are the Honda hybrids, ~15 hp EV vs. ~100 hp ICE. Because the engine torque provides the bottom end, a substantially smaller engine can still provide adequate driving experience.
- electric power drive < engine power - examples are the Toyota drive hybrids, 30 hp EV vs. ~70 hp ICE (NHW11.) The car has a non-trival amount of electric power, enough to handle slow speeds, ~25 mph, for distances up to a mile.
- electric power drive ~= engine power - examples are the Toyota plug-in hybrids. I don't have the EV vs. ICE power ratios (too lazy to lookup) but they extend the EV distances to 10 miles and speeds up to 50 mph.
- electric power > engine power - examples are the GM Volt and several concept cars including the Jaguar C-X75. Sometimes called extended range EV, the only production version is not so impressive on gas power.
That a hybrid electric can be built does not mean it should be. In the case of the Jaguar C-X75, this is an experiment investigating the limits. I support experimentation but there is a big gap between what can be built, a lab experiment, and a practical hybrid electric.
One serious flaw of the Volt is not so good gas assisted mileage. What this tells me is there is an efficiency problem in that design. Without a Volt to test, I can not diagnose the problem(s) but the gross mileage numbers indicate they are not able to equal the Toyota efficiency. It is not even close when the vehicle volume and non-electric, miles per gallon. But it is also GM's first production hybrid of merit ... the Precept was the unbuilt, GM prototype of the Volt, 10 years ago.
Bob Wilson