[Christ]

I was joking about the single. I don't work with those too much. Apparently, my joke struck on something that's actually workable, which wasn't my intent.

The one time I worked with a single, it wasn't imperative that it run at high power, and it was a diesel cycle engine. The intake air was drawn through the block, into a small supercharger, then into the cylinder. The exhaust was also routed through the block, to maintain increased combustion temps. It's a project I was working on with a shop teacher (not mine) to demonstrate heat effects on diesel combustion. The engine was only about 30 CC, something he'd made in his days as a casting mill operator, I guess.

What we found out was basically that while it was a good idea to keep the fuel hot and keep the block as hot as possible, the thing DID NOT like hot intake air, at all. The hotter the air got, the less power the engine was capable of producing, and the more fuel it required to produce the same power.

Since RPM remained relatively constant, the shop teacher could test the torque output at that speed by just measuring how much force in opposition it took to make the engine speed vary to the point where it wouldn't pick up speed again. Fairly inaccurate, but it worked for what we were playing with.

We actually found out that to some given extent, it is more efficient to have the coldest air possible going into the engine, and running extremely lean, than to run stoich with hot air. It's been almost 15 years since I was working on this, but if I recall correctly, we made it all the way down to something like 45:1 average AFR before it grenaded, with intake temps as low as 60*F.