シリンダライナ摺動面のレプリカ判定法

Abstract

Recently in the field of marine diesel engine, there is a remarkable trend to increase the Pmax. and the piston stroke in order to get higher effeciency. Therefore the cylinder liner and piston ring condition is getting more and more severe in the viewpoint of temperature, pressure and the exposure of the oil on the sliding surface. In addition, the effect of over cooling on the cylinder liner and the use of sulfur rich fuel have diversified the wear phenomena of rings and liners. With the situations above, it has become more important in the liner lubrication to reduce the wear rate with the minimum comsumption of lubricating oil as possible. In order to solve these problems it is necessary to recognize the various conditions of wear on the liner surfaces.In this study the replica observation method is investigated to evaluate those conditions in many vessels, and the following results are obtained.1. Replica wear modes are classified into six patterns - abrasion, adhesion, polish, corrosion, etching and steadite corrosion - according to their characteristic features. They can be grouped into two types in relation to the effect of corrosion.2. These relative wear rates are clarified in the wear mode diagram taking into account the degrees of mechanical and chemical wear.3. Since the steadite corrosion seriously affects the liner wear, it is very important to restrain such corrosion to get the minimum wear.4. The replica observation method is highly effective for judging the liner wear conditions and therefore, it can give us the fundamental approach to improve the liner wear.