This is just one step in a continuing development. Engines become smaller but charged give the same amount of power or more than existing engines. The engines a

This is just one step in a continuing development. Engines become smaller but charged give the same amount of power or more than existing engines. The engines are eventually only used for spinning a generator (with the rest of the drive train being electric) which means the engines can be explicitly designed to run short spurts at very high power output, very high efficiency but also higher wear (but that's ok because it doesn't run for 10 hours straight). The engines probably end up being tiny but charged diesel engines (diesel cycle is more efficient and diesel engines can easily run on various kinds of renewable or recycled oils) that are designed to charge the car batteries with the best possible efficiency in the shortest possible time. Most driving will be powered by the battery only within 100-200 mile radius, and people are probably fine with limiting the top speed of the vehicle on longer distances so that the tiny engine can remain tiny and weigh less.