Four cycle engines run hot and require heavy radiators and fans to cool them. Well then, why not add an extra power stroke that cools the engine. Voila, the six stroke engine!
Yes, a six stroke engine! At PESWiki they tell the story of Bruce Crower's great idea:
- The first four strokes are the same as an internal combustion engine.
In Crower's design, after the exhaust cycles out of the chamber, rather than squirting more fuel and air into the chamber, his design injects ordinary water. Inside the extremely hot chamber, the water immediately turns to steam, expanding to 1600 times its volume, which forces the piston down for a second power stroke. Another exhaust cycle pushes the steam out of the chamber, and then the six-stroke cycle begins again.
No Cooling System Required
- "Besides providing power, this water injection cycle cools the engine from within, making an engine's heavy radiator, coolant, and fans obsolete. Despite its lack of a conventional liquid cooling system, his bench engine is only warm to the touch while it is running."
Crower estimates that eventually his six-stroke engine could improve a typical engine’s fuel consumption by as much as forty percent.