6-Stroke Engine

I stumbled upon this very interesting piece about the designer of a 6-stroke engine: http://www.autoweek.com/apps/pbcs.dll/article?AID=/20060227/FREE/302270007/1023/THISWEEKSISSUE

After being intrigued enough to do some more research I found out that 6-stroke engines have actually been around for a while in prototype form and allow for cool-running, super efficient engines by converting the excess heat into steam that gives the whole thing an extra push.

The more I’ve been reading about this the more I think these engines would be a fantastic, cheap compromise between standard gasoline engines and uber-green power. They still burn fuel to keep the oil companies happy, so why haven’t they caught on?