CYLINDER LUBRICATING OIL COMPOSITION FOR CROSSHEAD-TYPE DIESEL ENGINE

摘要

The present invention provides a cylinder lubricating oil composition that is for a crosshead-type diesel engine and that has a low occurrence of deposits even when using a group II or group III base oil, wherein the composition results from combining (D) a metal-based cleaning agent and (E) an ashless dispersant with a base oil containing: (A) a mineral-oil-based lubricating base oil of which at least 90 mass% is saturated hydrocarbons, there is no greater than 0.03 mass% of sulfur by the amount of the element, the viscosity index is at least 80, and the kinematic viscosity at 100°C is 10-20 mm2/s; (B) at least 3 mass% in relation to the entire base oil of an extract containing at least 15% of aromatic hydrocarbon compounds (%CA) according to the composition analysis method stipulated in ASTM D2140 and arising as a byproduct of solvent refining during the process of producing the mineral-oil-based lubricating base oil; and (C) a polymer-compound-based synthetic oil that is the polymer of an olefin having at least 4 carbon atoms or is the hydride of same, and that has a kinematic viscosity at 100°C of 20-400 mm2/s.