A lubricating oil composition for reducing low-speed pre-ignition events or improving oxidation in a spark-ignited direct injection engine is disclosed. The composition includes a detergent additive which comprises either: an oil-soluble sulfonate including both magnesium and calcium as cations; or an oil-soluble salicylate including both magnesium and calcium as cations.

A lubricating oil composition including: a lubricant base oil; (A) a calcium salicylate detergent in an amount of 0.005 to 0.03 mass % in terms of calcium on the basis of the total mass of the composition; (B) a succinimide ashless dispersant in an amount of 0.005 to 0.25 mass % in terms of nitrogen on the basis of the total mass of the composition; (C) a nitrogen-containing antioxidant in an amount of 0.005 to 0.15 mass % in terms of nitrogen on the basis of the total mass of the composition; and optionally (D) a nitrogen-containing friction modifier in an amount of no more than 0.03 mass % in terms of nitrogen on the basis of the total mass of the composition, wherein a total content of any metallic detergent is 0.005 to 0.03 mass % in terms of metal on the basis of the total mass of the composition.

A method for lubricating an internal combustion engine, the method including: supplying a lubricating oil composition to a cylinder of an internal combustion engine, wherein the internal combustion engine has a mean effective pressure of no less than 1.3 MPa, wherein an integrated intensity ratio of peaks of CaO in a X-ray diffraction spectrum of an ash is no more than 16.5%, the ash being obtained by incinerating the lubricating oil composition in an air at 950° C.

The invention is directed to a zinc-free lubricating composition for an internal combustion engine containing a phosphorus anti-wear agent, an ashless antioxidant, and a metal-free basic detergent. The lubricating composition provides wear protection, deposit control, and improved acid control with reduced levels of metal-containing additives.

The invention provides a lubricant composition comprising an oil of lubricating viscosity and a protic acid salt of an N-hydrocarbyl-substituted gamma-(γ-) or delta-amino(thio)ester. The invention further relates to a method of lubricating a mechanical device with the lubricant composition.

A lubricating composition including: a base oil, a lubricant additive composition including, as a component (A), an organic molybdenum compound of the formula (1) described in the specification, and as a component (B), an amine compound of the formula (2) described in the specification, and a specific metal-based cleaner, wherein a content of the component (B) is 2.9 to 18.6 parts by mass relative to 100 parts by mass of molybdenum atoms of the component (A), and a content of the metal-based cleaner is 0.1% to 10% by mass relative to a total amount of the lubricating composition, wherein the lubricating composition does not include tetraalkyl thiuram disulphide, and wherein the component (A) in terms of the amount of molybdenum atoms is 400 to 1200 ppm by mass relative to a total amount of the lubricating composition.

The disclosed technology relates to hydrocarbyl- (e.g. alkyl-) phenol detergents and their salts, where the hydrocarbyl group includes moieties equivalent to 5 to 10 carbon branched polyene compounds. Such compounds and their salts are useful as lubricant additives.

The invention provides a compressor oil, wherein 2,6-di-tert-butylphenol and tris (2,4-di-tert-butylphenyl) phosphite are added to a base oil having a naphthene content of from 17 to 30% based on the total amount of the base oil, and has a pour point of −25° C. or lower. 2,6-di-tert-butylphenol is effective when it is contained in an amount of from 0.5 mass % to 6.0 mass % based on the total amount of the compressor oil, and tris (2,4-di-tert-butylphenyl) phosphite is effective when it is contained in an amount of from 0.3 mass % to 2.0 mass % based on the total amount of the compressor oil. Furthermore, adding an alkaline earth metal salt of alkylsalicylic acid in combination is even more effective. The amount thereof used is preferably from 0.05 mass % to 2.0 mass %.

The present invention relates to a lubricant composition containing: a base oil (A); at least one kind of calcium-based detergent (B) selected from (B1) calcium sulfonate having a base number of 5.00 mgKOH/g or more and 100 mgKOH/g or less, (B2) calcium salicylate having a branched acyclic hydrocarbon group, and (B3) overbased calcium phenate having a branched acyclic hydrocarbon group; and at least one kind of ashless detergent (C) selected from (C1) a hindered amine compound having one piperidine-derived backbone in a molecule, and (C2) a specific diethanolamine compound. In the lubricant composition, the calcium atom content is 100 ppm by mass or more and 600 ppm by mass or less with respect to the total mass of the lubricant composition, and the ratio (N.sub.C/Ca.sub.B) of the nitrogen atom content (N.sub.C) of the ashless detergent (C) to the calcium atom content (Ca.sub.B) of the calcium-based detergent (B) is 1.3 to 3.1 as a mass ratio.

The present invention relates to a lubricant composition containing: a base oil (A); at least one kind of calcium-based detergent (B) selected from (B1) calcium sulfonate having a base number of 5.00 mgKOH/g or more and 100 mgKOH/g or less, (B2) calcium salicylate having a branched acyclic hydrocarbon group, and (B3) overbased calcium phenate having a branched acyclic hydrocarbon group; and at least one kind of ashless detergent (C) selected from (C1) a hindered amine compound having one piperidine-derived backbone in a molecule, and (C2) a specific diethanolamine compound. In the lubricant composition, the calcium atom content is 100 ppm by mass or more and 600 ppm by mass or less with respect to the total mass of the lubricant composition, and the ratio (N.sub.C/Ca.sub.B) of the nitrogen atom content (N.sub.C) of the ashless detergent (C) to the calcium atom content (Ca.sub.B) of the calcium-based detergent (B) is 1.3 to 3.1 as a mass ratio.