writes "An Australian team is seeking funding for bringing an interesting idea to market: cylinder engines without piston rings. The idea is to use small groves that create a pressure wave that acts as a seal for the piston, eliminating the piston ring and the associated friction. Engines will then run cooler, can be more energy efficient and may even burn fuel more efficiently, at least according to the story at http://www.motoring.com.au/news/2013/aussie-invention-eliminates-piston-rings-40773. Mind you, they haven't even built a working prototype yet. If it works I'd love to fit this into an older car..."