CYLINDER LUBRICATING OIL COMPOSITION FOR CROSSHEAD TYPE DIESEL ENGINE

摘要

A cylinder lubricating oil composition for diesel engines of the crosshead type is provided which is excellent in heat resistance and anti-seizing properties. The composition comprises a lube base oil and a phenate type metallic detergent (A) having an alkylphenol sulfide metal salt having five or more alkylphenol structures in the same molecule. This composition is useful especially in a two-stroke cycle diesel engine operated under such conditions that any or all of the following are satisfied: the bore size is 70 cm or larger; the engine is an ultra-long-stroke engine with a mean piston speed of 8 m/s or higher; the combustion pressure is 1.8 MPa or higher in terms of brake mean effective pressure (BMEP); and the cylinder wall temperature reaches 250°C or higher.