| 摘要 |
PROBLEM TO BE SOLVED: To provide a trunk piston marine engine lubricating oil composition for a medium speed stroke compression-ignited (diesel) marine engine, in which an overbased metal carboxylate detergent of a specified basicity index is used in a proper rate. SOLUTION: This trunk piston marine engine lubricating oil composition comprises, in a major amount, an oil of a lubricating viscosity containing a group II basestock of≥50 mass%, and, in respective minor amount, (A) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent having a basicity index of≥5.5 and (B) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent having a basicity index of≤2, or is prepared by blending those. The ratio of the mass of a metal in the detergent (A) to the mass of a metal in the detergent (B) is≤10. The marine engine lubricating oil composition has a TBN (using ASTM D2896) of 20-60. COPYRIGHT: (C)2010,JPO&INPIT |
