Development Of Nitrided Oil Control Rings With Contoured Rails

The application of multipiece oil control rings (two segments or rails and one expander) to Otto engines is very efficient and has been used for many years. However, development work to improve their performance, durability and manufacturing costs is desirable. The contoured segment is an alternative to reduce the variation of oil ring unit pressure during engine life.

This paper shows the results of engine tests with this component, where nitrided segments with regular stainless steel expanders and nitrided expanders were used. The results showed satisfactory behaviour, with low wear between segments and nitrided expanders as well as between segments and the cylinder wall.