A lubricating oil composition for internal combustion engines containing a base oil (A), a metal-based detergent (B) containing a calcium-based detergent (B1), a zinc dialkyldithiophosphate (C), and a molybdenum-containing compound (D), wherein a calcium atom-equivalent content of the calcium-based detergent (B1) is more than 100 ppm by mass and 600 ppm by mass or less, based on a total amount of the composition, a magnesium atom-equivalent content of a magnesium-based detergent (B2) is less than 200 ppm by mass, based on the total amount of the composition, a sodium atom-equivalent content of a sodium-based detergent (B3) is less than 200 ppm by mass, based on the total amount of the composition, a content ratio of phosphorus derived from the zinc dialkyldithiophosphate (C) to calcium derived from the calcium-based detergent (B1) [P/Ca] is 0.25 or more by mass, and a sulfated ash content is 0.7% by mass or less; and a method for producing the composition.

The invention addresses a problem of providing a lubricating oil composition for gas engines capable of suppressing viscosity increase while reducing a sulfated ash content and excellent in high-temperature detergency and base number retention. The lubricating oil composition is used for gas engines and contains a base oil (A), at least one ash-free additive (B) selected from an ash-free sulfur-based antioxidant (B1) and a hindered amine compound (B2), and a boronated imide-type dispersant (C), and satisfies the following requirements (X1) to (X3): Requirement (X1): the sulfated ash content is 0.2% by mass or less. Requirement (X2): the content of the ash-free additive (B) is 1.2% by mass or less based on the total amount of the lubricating oil composition, provided that in the case where the ash-free additive (B) contains the hindered amine compound (B2), the content of the hindered amine compound (B2) is less than 1.0% by mass based on the total amount of the lubricating oil composition. Requirement (X3): the content of the boron atom derived from the boronated imide-type dispersant (C) is 200 ppm by mass or more based on the total amount of the lubricating oil composition.

The invention addresses a problem of providing a lubricating oil composition for gas engines capable of suppressing viscosity increase while reducing a sulfated ash content and excellent in high-temperature detergency and base number retention. The lubricating oil composition is used for gas engines and contains a base oil (A), at least one ash-free additive (B) selected from an ash-free sulfur-based antioxidant (B1) and a hindered amine compound (B2), and a boronated imide-type dispersant (C), and satisfies the following requirements (X1) to (X3): Requirement (X1): the sulfated ash content is 0.2% by mass or less. Requirement (X2): the content of the ash-free additive (B) is 1.2% by mass or less based on the total amount of the lubricating oil composition, provided that in the case where the ash-free additive (B) contains the hindered amine compound (B2), the content of the hindered amine compound (B2) is less than 1.0% by mass based on the total amount of the lubricating oil composition. Requirement (X3): the content of the boron atom derived from the boronated imide-type dispersant (C) is 200 ppm by mass or more based on the total amount of the lubricating oil composition.

Disclosed is a lubricating oil composition. The lubricating oil composition contains a lubricating base oil including mineral base oil, 4 to 15 mass % of an ester compound of a monovalent or polyvalent aliphatic carboxylic acid and a monovalent or polyvalent aliphatic alcohol, 400 to 1200 mass ppm of zinc dialkyl dithiophosphate in terms of a phosphorus element, 500 to 3000 mass ppm of a calcium-based detergent in terms of a calcium element, and 50 to 1000 mass ppm of a boron-modified succinimide-based dispersant in terms of a boron element, on the basis of the total amount of the lubricating oil composition.

Disclosed is a lubricating oil composition. The lubricating oil composition contains a lubricating base oil including mineral base oil, 4 to 15 mass % of an ester compound of a monovalent or polyvalent aliphatic carboxylic acid and a monovalent or polyvalent aliphatic alcohol, 400 to 1200 mass ppm of zinc dialkyl dithiophosphate in terms of a phosphorus element, 500 to 3000 mass ppm of a calcium-based detergent in terms of a calcium element, and 50 to 1000 mass ppm of a boron-modified succinimide-based dispersant in terms of a boron element, on the basis of the total amount of the lubricating oil composition.

A lubricant composition comprising an oil of lubricating viscosity and 0.01 to 5 percent by weight of a substantially sulfur-free alkyl phosphate amine salt, where at least 30 mole percent of the phosphorus atoms are in an alkyl pyrophosphate salt structure, exhibits good antiwear performance. In the phosphate amine salt, at least 80 mole percent of the alkyl groups are typically secondary alkyl groups of 3 to 12 carbon atoms.

A lubricant composition comprising an oil of lubricating viscosity and 0.01 to 5 percent by weight of a substantially sulfur-free alkyl phosphate amine salt, where at least 30 mole percent of the phosphorus atoms are in an alkyl pyrophosphate salt structure, exhibits good antiwear performance. In the phosphate amine salt, at least 80 mole percent of the alkyl groups are typically secondary alkyl groups of 3 to 12 carbon atoms.

Provided is a lubricating oil composition for a gas engine, comprising a base oil (A), a calcium-based detergent (B), and an alkenyl succinimide (C), wherein a content of calcium atoms is 0.09 to 0.17 mass % based on the total amount of the lubricating oil composition, the component (C) comprises a non-boron-modified alkenyl bis-succinimide (C1), and a content of boron atoms derived from the component (C) is less than 0.02 mass % based on the total amount of the lubricating oil composition.

Provided is a lubricating oil composition for a gas engine, comprising a base oil (A), a calcium-based detergent (B), and an alkenyl succinimide (C), wherein a content of calcium atoms is 0.09 to 0.17 mass % based on the total amount of the lubricating oil composition, the component (C) comprises a non-boron-modified alkenyl bis-succinimide (C1), and a content of boron atoms derived from the component (C) is less than 0.02 mass % based on the total amount of the lubricating oil composition.

A lubricating oil composition comprising greater than 50 wt. % of a base oil of lubricating viscosity; an amount of one or more ester(s) of a polyhydric alcohol; an amount of one or more boron-containing dispersant(s); wherein a ratio of the amount of the one or more ester(s) of a polyhydric alcohol in weight percent provided to the lubricating oil composition, to an amount of boron in weight percent provided by the one or more boron-containing dispersant(s), based on the total weight of the lubricating oil composition is less than 40. The lubricating oil composition has improved corrosion performance in an engine or other mechanical components lubricated with the lubricating oil.