An object of the present invention is to provide a lubricating oil composition which, even while exhibiting an excellent friction reducing effect by combining plural types of molybdenum-based friction modifiers, has excellent high-temperature detergency, oxidation stability and copper corrosion resistance. The object has been achieved by a lubricating oil composition containing a base oil (A), a molybdenum-based friction modifier (B), a metal-based detergent (C), and an ash-free dispersant (D), wherein the molybdenum-based friction modifier (B) contains two or more selected from the group consisting of a binuclear molybdenum dithiocarbamate (B1), a trinuclear molybdenum dithiocarbamate (B2), and a molybdenum-amine complex (B3); the metal-based detergent (C) contains a sulfur atom; the ash-free dispersant (D) contains a nitrogen atom; the acid value derived from the binuclear molybdenum dithiocarbamate (B1) and the trinuclear molybdenum dithiocarbamate (B2) is less than 0.04 mgKOH/g; the content ratio of a sulfur content (C.sub.S) derived from the metal-based detergent (C) to a nitrogen content (D.sub.N) derived from the ash-free dispersant (D), [(C.sub.S)/(D.sub.N)] is 0.30 to 0.85 in terms of the mass ratio; and the phosphorus content based on the total amount of the lubricating oil composition is more than 0.04% by mass and less than 0.10% by mass.

Provided is a lubricating oil composition which has an excellent effect of reducing the friction coefficient even when a member having a low surface roughness in a low oil temperature region is lubricated, by means of a lubricating oil composition which contains a mineral base oil (A), a polymer (B) having a weight average molecular weight (Mw) of 100 to 15,000, and a molybdenum-based friction modifier (M) and has a kinematic viscosity at 40? C. of 35.0 mm.sup.2/s or less.

A lubricating oil composition, including a base oil (P) and a copolymer (X). The copolymer (X) contains the following structural units (a) to (c): structural unit (a): a structural unit derived from a monomer (A) having a (meth)acryloyl group and a linear or branched alkyl group having 6 to 24 carbon atoms, structural unit (b): a structural unit derived from a monomer (B) having a (meth)acryloyl group and a polar group, and structural unit (c): a structural unit derived from a monomer (C) having a polymerizable functional group and a cyclic structural group. The copolymer (X) has a mass-average molecular weight (Mw) of 5,000 to 50,000, a content of the copolymer (X) in terms of resin content is 0.10% by mass to 2.5% by mass based on the total amount of the lubricating oil composition, and the lubricating oil composition has a 100? C. kinematic viscosity of 8.2 mm.sup.2/s or less.

Provided are a lubricating oil composition for internal combustion engine, containing a lubricating base oil containing a mineral oil and/or a synthetic oil, (A) an overbased calcium salicylate, (B) an overbased magnesium detergent, (C) a binuclear and/or trinuclear organic molybdenum compound, (D) a phenol-based antioxidant, and (E) an amine-based antioxidant, wherein the component (C), the component (D), and the component (E) are contained in specified contents on the basis of the whole amount of the lubricating oil composition; a method for producing the lubricating oil composition for internal combustion engine; and a lubrication method including using the lubricating oil composition for internal combustion engine.

A method for manufacturing of steel articles comprises nitriding (210) a steel article at a nitrification temperature in the interval 350-650 C., giving a nitrided steel article. The nitrided steel article is quenched (220) in a reactive quenching oil from the nitrification temperature. The reactive quenching oil comprises at least one of S, P, B, Mo and W. Thereby, the quenching additionally comprises coating (222) of the nitrided steel article by a solid lubricant comprising at least one of S, P, B, Mo and W. An apparatus for manufacturing of steel articles, a quenching oil and a steel article produced by the method are also disclosed.

A lubricating composition for use in heavy duty diesel engines which is formulated to allow the use of organo-molybdenum compounds but which overcomes the issue of Cu and/or Pb corrosion and also maintains elastomer seal compatibility. The lubricant is characterized by having a composition comprising (A) an organo-molybdenum compound, (B) an alkylated diphenylamine derivative of triazole, (C) base oil, and optionally (D) one or more additives selected from the group including antioxidants, dispersants, detergents, anti-wear additives, extreme pressure additives, friction modifiers, rust inhibitors, corrosion inhibitors, seal swell agents, anti-foaming agents, pour point depressants and viscosity index modifiers.

Provided is an internal combustion engine lubricating oil composition having a major amount of an oil of lubricating viscosity; a combination of alkaline earth metal alkylhydroxybenzoate detergents; at least about 50 to about 500 ppm of boron from a boron containing detergent; a molybdenum containing compound in an amount to provide the lubricating oil composition from about 100 to about 1500 ppm molybdenum; a ZnDTP compound; where the composition comprises magnesium in an amount from about 100 to about 800 ppm, and calcium in an amount from about 500 to about 2000 ppm.

The present disclosure generally relates to an internal combustion engine lubricating oil composition comprising: (a) a major amount of a base oil of lubricating viscosity; (b) a nitrogen-containing dispersant; (c) an alkaline earth metal containing detergent; (d) a compound comprising the reaction product of: (i) a nitrogen-containing reactant, wherein the nitrogen-containing reactant comprises an alkyl alkanolamide, an alkyl alkoxylated alkanolamide, an alkyl alkanolamine, an alkyl alkoxylated alkanolamine or mixtures thereof, (ii) a source of boron, and (iii) a hydrocarbyl polyol, having at least three hydroxyl groups.

Also provided is a method for improving fresh oil or used oil fuel economy in an internal combustion engine comprising lubricating said engine with said lubricating oil composition.

Disclosed is a method for preventing or reducing low speed pre-ignition in an engine lubricated with a formulated oil. The formulated oil has a composition comprising at least one oil soluble or oil dispersible cobalt-containing compound.

Disclosed is a lubricating oil composition comprising the reaction product of a nitrogen containing reactant wherein the nitrogen containing reactant comprises an alkyl di-alkanolamide, an alkyl di-alkanolamine, or mixtures thereof; an acidic molybdenum compound; and a salicylate compound. Also disclosed is a method for operating an internal combustion engine comprising said lubricating composition and a method for preparing a molybdenum containing friction modifier.