I have a Volt which has a 1.8L ICE with a generator close coupled on the shaft. I drove it on an 1800 mile round trip from Georgia to PA and back over the mountains, wife , two suitcases and a cooler. Averaged 43.3 mpg using the ICE. The car keeps a life time average and with 10K miles lifetime average is 65.x mpg. I always slow charge it on 120VAC from my home. (no other source available) What makes this so good is my home electrical supply is from solar. You can barely tell if the engine is running from the sound. You can not hear the engine start because there is no starter motor. No need since the generator will act as a motor using VFD technology spin the motor up then the gas, compression and spark are applied and it is running.

Paul