Investigation on Friction Behavior of a Single Cylinder Gasoline Engine

In order to improve the performance and fuel economy of a reciprocating engine, it is important to reduce the overall engine frictional losses. In this paper, author conducts an experimental study on the friction characteristics due to pumping loss, valve-train system, piston assembly, auxiliaries and transmission for a 110cc, single cylinder 4-stroke gasoline engine using frictional strip-down analysis. Friction strip-down method is commonly used to investigate the frictional contribution of various engine elements at high speeds and for better understanding of the make-up of the total engine friction. The engine friction measurements for the particular engine are carried out on a motoring test rig at different engine speeds. In addition, the effect of engine operating parameters such as oil temperature and oil quantity in engine sump is also presented in detail. Finally, the author showcases that there is a reduction in friction for the upgrade engine by 8% compared to previous model by modifying the coating on piston skirt and changing the oil grade.