“you can make a gas engine one hell of a lot more efficient if it only has to run at one speed.”
This is basically the principle of the engine in the Prius. As I’m sure you know, the cam can only be at peak efficiency at one RPM and one load. The compression ration of this engine and others of its type is fairly mindblowing:
http://en.wikipedia.org/wiki/Atkinson_cycle
Of course, a DIESEL is really the best engine for a serious engine-generator combination. Too bad that it’s basically impossible to sell a simple, efficient one for automotive use in the US, due to certain departments headed for extinction by 2017.
It’s really unfortunate how the EPA emission laws have crippled diesels in the US, especially on-road diesels.
Low compression, massive EGR, wasted fuel for DPF burnoffs, etc.
If you could use the latest super high pressure injection and electronics technology with 1990s era emission laws, you’d see some stunningly good fuel economy.
what is the smallest diesel engine commercially available? do you know?