An observation:
Many people seem to be under the impression that series hybrid drivetrains (where the ICE powerplant turns a generator which powers a motor) are superior to parallel hybrid (where the ICE can spin the wheels directly).
I think a lot of this comes from knowledge of diesel-electric locomotives, and trains are known to be efficient. But, in fact, those trains would be even more efficient of they could parallelize the diesel engine - that's just really hard, and isn't the point.
Spinning a generator to make power which you then use to spin a motor introduces losses.
Diesel-electric locomotives are mainly solving the complexity of getting thousands of tons of steel to move with a (relatively) small diesel engine. Much easier to use electricity than design a mechanical transmission that could handle that.
But if you could feasibly spin the wheels with the engine, it would be more efficient to cut out that step - which is why most hybrids cars do this whenever possible.
How do these losses compare to gearbox-related losses (as in, losses in the gearbox and losses due to operating the engine at suboptimal RPM for the load)?
