Pore Ensemble Statistics in Application to Lubrication Under Reciprocating Motion

Abstract

The concept of pore ensemble is applied to piston ring lubrication. The solution of the two-dimensional Reynolds equation is given for reciprocating motion of a compression piston ring with circular micropores of rectangular profile on its sliding surface. Minimal film thickness between ring and cylinder is considered for identical and diverse pore ensembles. It was shown that the pores provide hydrodynamic load support, sufficient to keep the ring and cylinder apart even in cases of a linear ring profile and ring surface parallelism to the cylinder wall, through the whole piston stroke including the dead points. Calculations for a id pore cluster with diverse pore radius and depth (each with not less than 20 percent variance) show that fluctuation of the resulting film thickness is reduced up to 0.5 percent variance, while the thickness values of ensembles of diverse pores differ by more than 1. 5 times from that found for an identical pore population. There is apparently no need for perfect identity of the pores during production, but pore ensemble statistics must be taken into consideration in proper lubrication calculations. In general, the pore ensemble is an essential aspect in exact determination of the load support and better insight is provided into the tribological behavior of pore-covered surfaces.

Presented at the 54th Annual Meeting Las Vegas, Nevada May 23–27, 1999

KEY WORDS:

• Squeeze-Film Lubrication
• Piston Ring
• Statistical Analysis
• Micropore Ensemble

Notes

Presented at the 54th Annual Meeting Las Vegas, Nevada May 23–27, 1999