Brit Hybrid
 

Way back when...

I've never understood the advantages of a diesel/petrol engine which powers a generator to propel a vehicle.
Logic dictates that by adding the intermediary electrical generator efficiency is degraded.
Seeking enlightenment I stumbled upon this site:

HOW DOES DIESEL-ELECTRIC SAVE FUEL?

In all honesty, whilst I am better informed, I am none the wiser.

The article is about boats; I'm mainly thinking about cars:

For one thing, the diesel engine is not directly hooked up to the wheels, so at least one part of the question really is whether all of the components between the diesel motor and the wheels are more or less efficient than the equivalent for the electric motor. Every moving piece is lost power, and an electric motor doesn't need a transmission. This is before all of the complicated analysis in the article, which, if I got the gist correctly, is primarily concerned with the decoupling of engine/generator speed and motor speed, allowing the generator to operate at ideal RPMs for efficiency, while supporting a range of speed/power combinations on the motor.

Add a battery, and you can save the energy that a diesel engine otherwise would lose when idling. Add regenerative brakes, and you can also save the energy otherwise lost in heat and brake pad degradation.

Since torque is necessary to get the mass in motion and electric motors develop maximum torque at zero rpm, you can get away with small motors on two or four wheels.
The diesel or petrol engine can be very small and still power a generator big enough to supply power. Plus the engine will be designed and tuned to run at a specified constant rpm for maximum efficiency. With an engine accelerating and decelerating both waste fuel, and can't run below a stoichiometric fuel ratio of 14.7:1 safely. But running at a constant speed/load it can be a little leaner.

Two commu--two commutators?!?!?!?!?!?!Attachment 63325

shhhh

don't raise your voice, we don't want to alarm mr quirk