LUBRICATING OIL COMPOSITION FOR AN INTERNAL COMBUSTION ENGINE

摘要

The present invention provides a lubricating oil composition comprising a lube base oil comprising a mineral oil and/or a synthetic oil; (A) an alkenylsuccinimide or an alkylsuccinimide and/or a boron-containing derivative thereof in an amount of 0.01 to 0.14 % by mass based on the composition in terms of the nitrogen content as an ashless dispersant, wherein an alkenylsuccic acid monoimide or an alkylsuccinic acid monoimide and/or a boron-containing derivative thereof in the ashless dispersant is 0.05 % by mass or less in terms of nitrogen content; and (B) a dialkyldiphenylamine compound in an amount of 0.3 to 5.0 % by mass and a hindered phenol compound in an amount of 0 to 2.5 % by mass based on the composition as an antioxidant, and (C) a sulfated ash of the lubricating oil composition is 1.2 % by mass or less. The lubricating oil composition suitable for internal combustion engines has excellent oxidation stability despite low ash content, exhibits small increase in viscosity and acid number, and can prolong the interval (distance or time) required for changing lubricating oil.