Well, maybe... An Australian company is working on a new invention for cylinder engines without piston rings.

Goodbye, piston rings!

No working prototype has yet been built, but the idea is to used specially-grooved piston heads to create an air pressure seal in place of a ring, virtually eliminating friction in the process.

http://www.motoring.com.au/news/2013/auss...

Vapourware, or the next great thing in internal combustion?