A literature review of lacquer formation in medium-speed and low-speed engines

This paper reviews the studies on lacquer formation in medium-speed and low-speed engines. Lacquer mainly forms in the cylinder liner and fuel injection pump. This causes increased oil consumption, sticking of the fuel injection pump, scuffing in the cylinder liner, and so on. The mechanisms and causes of lacquer formation that have been proposed so far are introduced, and an explanation is given on the physical and chemical properties of lacquer formation by various analytical methods, such as melting test by acids, surface roughness measurement, pull-off test, and visual inspection. Moreover, a comparison is made of several experimental methods suggested in previous studies related to lacquer formation. Methods to prevent or remove lacquer formation in medium and low speed engines are also presented. In addition, this paper describes fundamental ongoing research.