Practical challenges in determining piston ring friction

Abstract

Practical challenges from both experiment and calculation sides were discussed for determining two piece twin land oil control ring friction. A floating liner engine was used for twin land oil control ring study. Effects of floating liner engine system dynamics and piston skirt friction were addressed and methods to mitigate them were discussed. A deterministic twin land oil control ring model was used for ring friction calculation. Variation of the surface roughness at different spots of the liner and its effects on both hydrodynamic and boundary lubrication predictions were discussed. A multi-point correlation method was introduced to address surface variation effects on the twin land oil control ring model. Ring land width variation between two lands as well as along the circumference and its effects on calculation were shown, and methods to address it were discussed. By taking all these necessary steps in both experiments and calculations, this study shows that a reasonable match can be achieved between the measured and calculated friction, which covers all three lubrication regimes. This study lays a foundation for realistically predicting the friction of piston rings in internal combustion engines.

Multi-Scale Surface Texturing in Tribology—Current Knowledge and Future Perspectives

“…Li and Chen proposed a deterministic mixed-lubrication model applied to the simulation of the piston ring cylinder liner contact of internal combustion engines. The model is based upon the calculation of the oil transport and the hydrodynamic pressure generation for the contact between a parallel and flat rigid plane sliding against a rough surface [131][132][133][134][135]. Similarly, Profito et al presented a deterministic mixed-lubrication model based upon the simultaneous solution of the asperity contact and fluid flow problems at the roughness scale considering inter-asperity mass-conservative cavitation.…”

A comprehensive study of the effects of honing patterns on twin-land oil control rings friction using both a numerical model and a floating liner engine

“…Liao et al. 13,14 and Westerfield et al. 15 used a floating liner engine to study the piston ring frictional behavior under motored and fired conditions with different engine speeds, ring designs, lubricants, and liner surfaces.…”

Determination of fundamental parameters for the cross-hatched cylinder liner micro-geometry

“…So far, no obvious problems were detected; however, future work will require additional verifications. Liao et al 37 and Chen 38 discussed this point in their work.…”