Development of Ceramic Cam Roller Follower for Engine Application

This paper describes the development of the ceramic cam roller follower manufactured from silicon nitride. The impact strength of the ceramic roller was investigated and proven to have sufficient strength and reliability for use in automotive engine applications. Motor simulation tests were conducted in order to study the best design for the ceramic cam roller. Results from testing show that super finishing of the roller surface is necessary in order to prevent severe wear of the metal shaft and cam. Optimum bearing clearance range was also studied. Performance tests were conducted in order to study the wear properties of the ceramic cam roller. Wear of the tested cam shaft when using the ceramic roller, was less than the conventional steel roller, even though the calculated contact stress was higher. The total amount of wear of the valve train components was significantly reduced when using the ceramic cam roller, when compared to the conventional steel roller. The ceramic cam roller is especially suitable for use in diesel engine applications, which require higher wear resistance and reliability in the valve train system.