Friction force measurement and analysis of the rotating liner engine

As emissions regulations become more stringent and fuel prices increase at a significant rate, the fuel efficiency of piston engines becomes more important than ever. Since most of the engine’s friction losses are from the piston/ring assembly, it is indispensable to reduce the piston/ring assembly friction for better fuel economy. The Rotating Liner Engine (RLE) was developed to remove the boundary lubrication of the piston/ring assembly friction through cylinder liner rotation. Even though the RLE was initially developed mainly by Dr. Dardalis several years ago, the friction reduction effect of the RLE was not confirmed except via preliminary motoring tests using a crude dynamometer. The main purpose of this dissertation is to confirm the RLE effect on piston assembly friction reduction using sophisticated measurement methods. Three different friction measurement methods were applied in measuring the friction force difference between a baseline engine and a prototype RLE. Through the use of three different friction measurement methods, the friction reduction of the RLE has been confirmed via this dissertation research and each of the friction measurement methods is also compared based on its measurement results. The analysis of the friction mechanism of the baseline engine was performed using the instantaneous IMEP method and a commercial simulation program called RINGPAK. Through the use of experimental methods and the simulation, the friction mechanism of the piston/ring assembly is analyzed. The limitation of the experimental and the calculation methods is also discussed.