Any one here know how a freight train runs? Their Diesel-Electric, huge Diesel engine, working as a generator to power an electric motor at each wheel. Why not scale down that tech for a car? I know it's not fully electric, but it is very efficient. Aside from that, Sam Diesel never actually intended for his engine to run on a petroleum product, that's why he was killed, thrown overboard while crossing the English Channel.
Speaking of trains, I think steam power is a technology that needs revisited. Those old trains moved massive loads with as few as two, four inch pistons. Granted they had a two or three foot stroke. Most of the size and mass of a steam engine, was that enormous boiler. Lets apply today's tech to the steam power "problem", see where we go. Most of America's large warships are powered by steam, granted it's nuclear steam, but steam nonetheless. Lets look into this, I'm not saying let's build nuke cars, but I'd drive the Stanley Steamer happily. In fact I once put serious thought into converting a F150 to steam power. Never did obviously, but not everyone is as broke and ignorant as I.