There is a report that a new Electric Vehicle planned by Volvo incorporates a liquid fuel cabin heater:
What I find interesting here is the comments after the article which make it clear this is far from a new idea. I was aware of the old air cooled VW Beetles in the 1960s that had accessory cabin heaters which burned gasoline. (I heard descriptions of these heaters failing which gave new meaning to the phrase Flame Out. As in flames coming out of the dash vents.) But several 1990 vintage EVs also used some variety of liquid fuel cabin heaters as do many (most?) contemporary EVs in Norway, where there are a lot of EVs. Hmm, does that oil producing country know something we don't?
I'll stick with the long underwear and wool socks, thank you very much. But great idea. Even the Corvair used a liquid fuel cabin heater. (I didn't know the Corvair had an air cooled engine.)
Does anyone know if E85 burning at atmospheric pressure in a simple furnace type of heat exchanger burns more cleanly than under the crazy cycles of a piston engine? I assume so. Now where does the heater exhaust go in an automotive package? I presume a tail pipe, not a chimney or (God forbid) the cabin?
Still, liquid fuels are efficient at providing heat and electricity is efficient and smooth at providing motive force. Use the best tool for the job.