New Piston Ring Innovations to Help Control Automotive Engine Emissions

This paper briefly reviews the progress in reducing emissions over the past eight years through improved piston ring designs and compatible facings. The newer emissions control laws for 1976 require considerable further work in reducing emissions from every possible source.

The authors discuss the green engine effect and suggest the use of reduced-friction piston rings to yield assembly-line emissions test results more nearly representative of the emissions from an engine after extended break-in running.

To reduce oil contamination for the purpose of conserving natural resources by extending oil change intervals and also to reduce emissions, the writers propose the use of zero blowby piston rings and discuss a novel design.

New piston ring facings may also play a part in improving durability and compatibility when ashless oils are specified and when the piston rings must be mounted at the top of the piston.