Statistical Study of Ring Geometry Effect on Piston Ring/Liner Tribology Using Classical Design of Experiment

An instantaneous piston ring/liner friction model has been presented to estimate the minimum oil film thickness and power loss contributed by piston rings under hydrodynamic lubrication. The model is based on lubrication theory considering lubricant viscosity variation with respect to temperature. A numerical scheme is developed to solve Reynolds and load equilibrium equations simultaneously to obtain the cyclic variation of oil film thickness and power loss. The model considers the ring profile geometry, the ring mechanical properties and their effects on the tribological performance of piston ring. The relevant trends and relations between parameters are considered with relatively simple approach to compute the minimum oil film thickness and mechanical power loss. Besides, Design of Experiment (DOE) technique and ANOVA analysis are employed to determine the effect of influential parameters such as ring width, ring crown height, ring elastic properties and ring end gap on the average power loss and average minimum oil film thickness. The statistical observation revealed that the main effect of ring width, ring crown height, ring tension force have prime importance and affect the response factors.