Lubricant transport across the piston ring with flat and triangular lubrication injection profiles on the liner in large two-stroke marine diesel engines

Abstract

A theoretical investigation of the lubricant transport across the top compression piston ring in a large two-stroke marine diesel engine is presented. A numerical model for solving Reynolds equation between the piston ring and cylinder liner based on the finite difference method in one dimension has been made. The model includes force equilibrium of the piston ring, perturbation of Reynolds equation, and transient mass conservation. The model represents a new method of achieving mass conservation across the piston ring and between different time-dependent positions. For analyzing the lubricant transport across the piston ring, two different kinds of initial lubricant profile on the liner and two different kinds of load are investigated i.e. a flat profile and an approximated triangular profile as well as no load and a combustion load based on a combustion pressure profile. The impact from the different load conditions and different lubricant profiles on the liner are presented for film thicknesses, development in the lubricant profiles on the liner as well as the lubricant consumption at each stroke.