Importance

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Abstract

The lubricating oil composition for spark-ignition internal combustion engine according to the present invention is a lubricating oil composition to be used for a spark-ignition internal combustion engine including a piston having a piston ring, in which a total tension per piston of tensions applied to the piston ring is 30 N or less, the lubricating oil composition being a lubricating oil composition comprising a base oil, (A) an organic metal-based additive containing an alkali metal and/or an alkaline earth metal, and (B) an organic zinc-based additive, wherein a concentration of the component (A) on a basis of the total amount of the lubricating oil composition is 0.15% by mass or less as converted into a metal content; a concentration of the component (B) on a basis of the total amount of the lubricating oil composition is 0.15% by mass or less as converted into a zinc content; the product of the concentration (% by mass) of the component (A) and a base number (mgKOH/g) of the lubricating oil composition is 1.3 or less; the product of the concentration (% by mass) of the component (B) and an acid number (mgKOH/g) of the lubricating oil composition is 1.2 or less; and the lubricating oil composition has a Noack evaporation loss of 10% by mass or more and a kinematic viscosity at 100° C. of 9.3 mm²/s or less. The lubricating oil composition for spark-ignition internal combustion engine according to the present invention is capable of preventing a deterioration of the combustion state of a spark-ignition internal combustion engine.

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First Claim