If only Chevy had been able to deliver on the Volt’s original concept (with the electric motor connected only to a generator)— it turned out that that arrangem

If only Chevy had been able to deliver on the Volt’s original concept (with the electric motor connected only to a generator)— it turned out that that arrangement was actually pretty inefficient, and the production car ended up being more of a traditional series hybrid approach similar to the Prius (with the ICE and electric motors connected through a planetary gearset so both can drive the wheels). BMW does something similar to the Volt’s original concept with the Range Extender in the i3– that actually is a gasoline engine coupled to a generator; it never directly drives the wheels, and it can’t be used as the car’s only power source (once the battery’s dead, you’re done, even with a full tank of gas).