Piston Compression Ring Elastodynamics and Ring–Liner Elastohydrodynamic Lubrication Correlation Analysis

Abstract

Friction loss in an internal combustion engine largely depends on elastohydrodynamic lubrication. The piston compression ring is a contributor to such parasitic losses in the piston subsystem. The complex elastodynamics of the ring are responsible for the transient and regime-altering film that affects the elastohydrodynamic lubrication of the ring liner contact conjunction. The current paper will discuss the ring radial, lateral deformation, and axial twist, and its effect on the film profile of the compression ring and its subsequent effect on tribological characteristics like elastohydrodynamic pressure, friction, and lubricant. A finite difference technique is used to solve the elastohydrodynamic issue of elastodynamic piston compression by introducing the elastodynamically influenced film thickness into the lubrication model. The results show that consideration of the elastodynamics predicts a 23.53% reduction in friction power loss in the power stroke due to the elastodynamic ring compared to the rigid ring. The elastodynamic effect improves the lubricant oil flow into the conjunction. A finite element simulation predicts a von-Mises stress of 0.414 N/mm2, and a maximum deformation of 0.513 µm at the core and coating interface is observed at the ring–ring groove contact. The sustainability of EHL in this case largely depends on the ring–liner elastodynamics.