:’) This article sez diesel, maybe they did it twice?
Top Gear Builds a Volt of Its Own
http://www.wired.com/2009/11/top-gear-builds-a-volt-of-its-own/
That’s the EV in question. Diesel, gasoline, I remembered pretty good for me. That would have made it more efficient, both at fuel economy and noxious fumes. :)