| abstract |
A lubricating oil composition for internal combustion engine that especially excels in high-temperature cleanness and ensures effective functioning of a metallic cleaning agent even under conditions such that moisture is mixed and accumulated therein; in particular, a lubricating oil composition for internal combustion engine that is suitable for use in an internal combustion engine of hybrid auto. The lubricating oil composition is one comprising, as a main component, lubricating base oil (A) of 1 to 8 mm2/s kinematic viscosity at 100°C, -15°C or below fluid point, 100°C or higher aniline point, 40 mass% or more paraffin content in saturated contents, 25 mass% or less monocyclic naphthene content, 35 mass% or less bi- to hexacyclic naphthene content, 2 or below iodine value and 6.3% or more tertiary carbon ratio to all constituent carbons, and further comprising, based on the whole mass of the composition, 0.005 to 0.5 mass%, in terms the mass of metal, of metallic cleaning agent (B), 0.005 to 0.2 mass%, in terms of the mass of boron, boronic succinimide ashless dispersant (C1) and 0.005 to 0.2 mass%, in terms of the mass of phosphorus, metal salt of phosphorus-containing acid (D). |