Eneos Corporation

Jx Nippon Oil Energy Corporation

Jxtg Nippon Oil & Energy Corporation

Hiromitsu Matsuda

Koji Hoshino

Shigeki Matsui

Kazuo Tagawa

Akira Takagi

Ryuichi Ueno

Hiroya Miyamoto

A lubricating oil composition for an internal combustion engine, the composition including: a lubricating base oil comprising at least one mineral base oil or at least one synthetic base oil or any combination thereof, the lubricating base oil having a kinematic viscosity at 100&#xb0; C. of 4.0 to 4.5 mm/s and a NOACK evaporation loss at 250&#xb0; C. of no more than 15 mass %; (A) a calcium-containing metallic detergent in an amount of no less than 1000 mass ppm and less than 2000 mass ppm in terms of calcium on the basis of the total mass of the composition; and optionally (C) a viscosity index improver in an amount of less than 1 mass % on the basis of the total mass of the composition.

Lubricating oil composition for internal combustion engine

A lubricating oil composition for an internal combustion engine includes: a lubricant base oil including at least one mineral base oil, at least one synthetic base oil, or any combination thereof, and having a kinematic viscosity at 100&#xb0; C. of 3.0 to 4.0 mm/s and a NOACK evaporation loss at 250&#xb0; C. of no more than 15 mass %; (A) a calcium-containing metallic detergent in an amount of no less than 1000 mass ppm and less than 2000 mass ppm in terms of calcium; (B) a magnesium-containing metallic detergent in an amount of 100 to 1000 mass ppm in terms of magnesium; (G) a zinc dialkyl dithiophosphate in an amount of no less than 600 mass ppm in terms of phosphorus; and optionally (C) a viscosity index improver in an amount of no more than 5 mass %.

A lubricating oil composition for an internal combustion engine, the composition including: a lubricating base oil comprising at least one mineral base oil or at least one synthetic base oil or any combination thereof, the lubricating base oil having a kinematic viscosity at 100&#xb0; C. of 4.0 to 4.5 mm/s and a NOACK evaporation loss at 250&#xb0; C. of no more than 15 mass %; (A) a calcium-containing metallic detergent in an amount of no less than 1000 mass ppm and less than 2000 mass ppm in terms of calcium on the basis of the total mass of the composition; (B) a magnesium-containing metallic detergent in an amount of 100 to 1000 mass ppm in terms of magnesium on the basis of the total mass of the composition; and optionally (C) a viscosity index improver in an amount of less than 1 mass % on the basis of the total mass of the composition.

The present invention provides a poly(meth)acrylate-based viscosity index improver comprising a core portion and three or more arm portions, wherein each of the arm portions consists of a polymer chain comprising a structural unit represented by the following formula (1), and one end of the polymer chain is bonded to the core portion, and wherein a weight-average molecular weight Mw is 100000 or more, and a ratio of the weight-average molecular weight Mw to a number average molecular weight Mn, Mw/Mn, is 1.6 or less.  [Rrepresents hydrogen or a methyl group, and Rrepresents a C1 to C36 alkyl group.]

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Tokyo, Japan

Hiromitsu Matsuda