| abstract |
The present invention relates to a cylinder lubricating oil for crosshead diesel engines. In addition to having conventional characteristics such as heat resistance, cleanliness, wear resistance, and the like, the cylinder lubricating oil can be used with fuel of any sulfur content and suppresses the amount of piston deposit even when the base number is excessive. In greater detail, the present invention relates to a cylinder lubricating oil composition which includes an ashless dispersant (B) and a metallic detergent (C) in a lubricant base oil (A), in which the product of the number average molecular weight, the content, and the effective concentration of the ashless dispersant (B) is at least 9000, and the endothermic peak temperature of the metallic detergent (C) as measured by DSC at a rate of temperature increase of 50° C./min is at most 460° C. |