Review of Lubricant Contamination and Diesel Engine Wear

Abstract

the the misfortune of diesel engines and their operators that the engine oil is Lube oil contamination is a primary also a depository of solid, liquid and reason for engine wear. The wear gaseous impurities. High levels of processes promoted by oil contamination lubricant contamination cause wear of lead to diminished fuel efficiency, mechanical components as well as shorter useful oil service life, reduced breakdown of the lube oil. The result component life, and loss of engine is performance degradation, short oil performance. Contaminant particles service intervals, and reduced engine responsible for this damage are in the life. size range of the dynamic lubricant This paper is an endeavor to films separating moving engine component establish a framework for understanding surfaces: 10 microns and smaller. By the tribological associations between diesel engine components and lube oil opposing surfaces these harmful contamination. Because of the high particles focus the load onto a small levels of solid impurities found in area, degrading the surface. This paper engine oil, and new technologies for reviews the nature of lubricant controlling these materials, emphasis is contamination, the modes of lubrication, placed on particulate contamination. and the primary mechanisms of engine The fundamental relationship between wear. The correlation between contaminant particle size and contamination and wear of engine lubricating film thickness evolves from components, as well as several important discussions on the nature of oil studies quantifying the effect of contamination, modes of engine contamination on engine wear and lubrication, and mechanisms of component performance, are discussed. It is wear. With this essential concept in concluded that operating with clean lube mind, wear of diesel engine components oil, maintained by 10 micron filtration is then examined. This is followed by a (plo 275), results in a diesel engine review of several documented diesel having better fuel economy, longer oil engine wear studies, in which the effect change intervals, superior performance, of contamination is quantified by and greater durability. varying particle concentrations using different levels of filtration. In addition, a recent survey of engine oil The Diesel Engine is receiving contamination is presented which increasing attention as a power plant indicates the current contamination because of fuel efficiency and life levels present in most engines, as well durability advantages. Over seventy as improvements that can be attained. percent of the trucks manufactured today use diesel power. A key component to the successful operation of the diesel 2. DIESEL ENGINE LUBRICANT CONTAMINATION engine is the lubricating oil. Major functions of the diesel engine lube oil TYPES OF CONTAMINATION There are ‘J include: cooling, friction reduction, three categories of oil contaminants and prevention of adhesion between active in engine wear processes: component surfaces. It is , however , to 1. Solid particles, including wear Copyright 1988 Society of Automotive Engineers, Inc. ‘3 making simultaneous contact with