Evaluation Method of Lubrication by Oil Sampling from Liner Wall for Marine Diesel Engine

Abstract

It is important to develop a method to evaluate both the cylinder oil distribution and its deterioration on the cylinder liner surfaces for two-stroke marine diesel engines. This paper describes a newly developed method for sampling cylinder oil on the liner wall and its evaluation under engine operating conditions.
(1) By periodically opening and closing its lube oil sampling valve via a control device operating in synchronization with the crank angle, the system is capable of automatically sampling the cylinder liner lube oil in a timely manner.
(2) Lube oil pH readings given by the system through its sampling and analysis functions during engine operation, are in fairly good agreement with the pH value which were later determined by analyzing the cylinder liner lube oil deposit sampled with filter paper, after stopping the engine.
(3) The system provides, by sampling from the position of the liner corresponding to the top ring at TDC, the data on lube oil properties, and shows that as the pH value goes down below 4 and retained TBN value drops below zero, the wear of both cylinder liners and piston rings increases appreciably.