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.

A lubricant composition for a compression-ignition internal combustion engine includes an amine and a detergent selected from metal sulfonates, phenates, salicylates, carboxylates, thiophosphonates, and combinations thereof. The lubricant composition has a TBN of from about 10 to about 100 mg KOH/g when tested according to ASTM D2896. The amine contributes from about 0.1 to about 28% of the TBN of the lubricant composition. Further, a method of lubricating an internal combustion engine with the lubricant composition includes the steps of injecting a fuel and the lubricant composition into a cylinder to form a mixture, and combusting the mixture via compression-ignition.

A lubricant composition for a compression-ignition internal combustion engine includes an amine and a detergent selected from metal sulfonates, phenates, salicylates, carboxylates, thiophosphonates, and combinations thereof. The lubricant composition has a TBN of from about 10 to about 100 mg KOH/g when tested according to ASTM D2896. The amine contributes from about 0.1 to about 28% of the TBN of the lubricant composition. Further, a method of lubricating an internal combustion engine with the lubricant composition includes the steps of injecting a fuel and the lubricant composition into a cylinder to form a mixture, and combusting the mixture via compression-ignition.

A lubricant composition includes a base oil present in an amount of greater than 70 parts by weight per 100 parts by weight of the lubricant composition and an antioxidant. The antioxidant has the structure: wherein each X is independently C-A or N, so long as at least one X is N but no more than two of X are N. Moreover, A is H, cyano or an electron donating group that: (1) has an atom having at least one lone pair of electrons that is bonded directly to the aromatic ring; or (2) is an aryl group or alkyl group. Further, each R is independently H, an alkyl group, or aryl group and each R′ is independently an alkyl group or an aryl group. ##STR00001##

A lubricant composition includes a base oil present in an amount of greater than 70 parts by weight per 100 parts by weight of the lubricant composition and an antioxidant. The antioxidant has the structure: wherein each X is independently C-A or N, so long as at least one X is N but no more than two of X are N. Moreover, A is H, cyano or an electron donating group that: (1) has an atom having at least one lone pair of electrons that is bonded directly to the aromatic ring; or (2) is an aryl group or alkyl group. Further, each R is independently H, an alkyl group, or aryl group and each R′ is independently an alkyl group or an aryl group. ##STR00001##

A method for reducing the tendency of a hydrocarbon fluid to oxidise comprises combining an additive having a chemical structure comprising a 6-membered aromatic ring sharing two adjacent aromatic carbon atoms with a 6- or 7-membered saturated heterocyclic ring, the 6- or 7-membered saturated heterocyclic ring comprising a nitrogen atom directly bonded to one of the shared carbon atoms to form a secondary amine and an atom selected from oxygen or nitrogen directly bonded to the other shared carbon atom, the remaining atoms in the 6- or 7-membered heterocyclic ring being carbon with the hydrocarbon fluid. The additive may also be used for protecting a system in which a hydrocarbon fluid is used from the effects of oxidation.

A lubricating oil composition contains a base oil and a rust inhibitor, in which the base oil has a gas chromatogram measured by gas chromatography satisfying the particular condition (), and the rust inhibitor is at least one selected from a first rust inhibitor, a second rust inhibitor, a third rust inhibitor, and a fourth rust inhibitor, and satisfies the particular condition ().

A lubricating oil composition contains a base oil and a rust inhibitor, in which the base oil has a gas chromatogram measured by gas chromatography satisfying the particular condition (), and the rust inhibitor is at least one selected from a first rust inhibitor, a second rust inhibitor, a third rust inhibitor, and a fourth rust inhibitor, and satisfies the particular condition ().

The present invention relates to a lubricating composition containing (a) an oil of lubricating viscosity; and (b) a compound selected from the group consisting of: (i) an ester-containing heterocycle; (ii) an amide-containing heterocycle; and (iii) a pyrimidine, wherein the ester-containing heterocycle and the amide-containing heterocycle have a hydrocarbyl group containing 6 to 40 carbon atoms. The invention further provides for a method of supplying an internal combustion engine with the lubricating composition.