The invention is directed to a method for reducing low speed pre-ignition events in a spark-ignited direct injection internal combustion engine by supplying to the sump a lubricant composition which contains an oil of lubricating viscosity and an overbased sodium detergent. The metal overbased detergent may be selected from sulfonate detergents, phenate detergents, and salicylate detergents, including sulfonate detergents with a metal ratio of at least 5.

The invention is directed to a method for reducing low speed pre-ignition events in a spark-ignited direct injection internal combustion engine by supplying to the sump a lubricant composition which contains an oil of lubricating viscosity and an overbased sodium detergent. The metal overbased detergent may be selected from sulfonate detergents, phenate detergents, and salicylate detergents, including sulfonate detergents with a metal ratio of at least 5.

Provided is a lubricating oil composition for engine equipped with a forced-induction mechanism capable of lowering the frequency of occurrence of LSPI, while using a calcium-based detergent. The lubricating oil composition for engine equipped with a forced-induction mechanism contains a base oil (A), a metal-containing surfactant (B) containing at least a calcium-containing surfactant (b1), and at least one basic compound (C) selected from a metal carbonate, a metal hydroxide, and an amine-based compound, wherein the content of sulfur contained in the metal-containing surfactant (B) is 0.2 mass % or more on the basis of the whole amount of the metal-containing surfactant (B); the content of a calcium atom is 0.08 to 0.20 mass % on the basis of the whole amount of the composition; and a mass ratio of the content of the basic compound (C) and the content of a calcium atom derived from the calcium-containing surfactant (b1) [(content of (C))/(calcium content derived from (b1))] is 2.0 or more.

A lubricating oil composition for an internal combustion engine, having (A) a lubricating base oil, (B) magnesium salicylate, (C) calcium salicylate, and (D) a viscosity index improver, wherein the lubricating oil composition has an HTHS viscosity at 150? C. of 1.7 mPa.Math.s or more and 2.3 mPa.Math.s or less, and an HTHS viscosity at 100? C. of 4.8 mPa.Math.s or less, can provide a lubricating oil composition for an internal combustion engine provided with high fuel-saving performance.

A lubricating oil composition for an internal combustion engine, having (A) a lubricating base oil including one or more mineral oil-based base oils and having a kinematic viscosity at 100? C. of 2.5 mm.sup.2/s or more and 4.0 mm.sup.2/s or less, and (B) magnesium salicylate in an amount of 0.1 mass % or more and 10 mass % or less based on a total amount of the composition, wherein the composition has an HTHS viscosity at 150? C. of 1.6 mPa.Math.s or more and 2.5 mPa.Math.s or less. The lubricating oil composition for an internal combustion engine has both high fuel-saving performance and LSPI-reducing effect.

The invention provides a method of lubricating a transmission which includes a synchronizer with a non-metallic surface, the method comprising supplying thereto a lubricant comprising: (a) an oil of lubricating viscosity; (b) an alkaline earth metal detergent; and (c) a non-aromatic carboxylic acid or a salt thereof having 8 to 24 carbon atoms.

The invention provides a method of lubricating a transmission which includes a synchronizer with a non-metallic surface, the method comprising supplying thereto a lubricant comprising: (a) an oil of lubricating viscosity; (b) an alkaline earth metal detergent; and (c) a non-aromatic carboxylic acid or a salt thereof having 8 to 24 carbon atoms.

Provided are a lubricating oil composition having a high intermetallic friction coefficient and having excellent clutch anti-shudder performance of excellent initial clutch anti-shudder performance and a long clutch anti-shudder lifetime, and a lubrication method and a transmission using the lubricating oil composition. The lubricating oil composition contains an amide compound (A) having a specific structure, a metal-based detergent (B), and at least one phosphorus acid ester (C) selected from an acid phosphate ester and an acid phosphite ester; and the lubrication method and the transmission use the lubricating oil composition.

A lubricating oil composition is provided which comprises (a) greater than 50 wt. % of a base oil of lubricating viscosity; and (b) 0.1 to 40 wt. % of an overbased alkaline earth metal alkyl-substituted hydroxyaromatic carboxylate having a TBN, on an actives basis, of at least 600 mg KOH/g, as determined by ASTM D 2896; wherein the lubricating oil composition is a monograde lubricating oil composition meeting specifications for SAE J300 revised January 2015 requirements for a SAE 20, 30, 40, 50, or 60 monograde engine oil, and has a TBN of 5 to 200 mg KOH/g, as determined by ASTM D2896.

A lubricating oil composition is provided which comprises (a) greater than 50 wt. % of a base oil of lubricating viscosity; and (b) 0.1 to 40 wt. % of an overbased alkaline earth metal alkyl-substituted hydroxyaromatic carboxylate having a TBN, on an actives basis, of at least 600 mg KOH/g, as determined by ASTM D 2896; wherein the lubricating oil composition is a monograde lubricating oil composition meeting specifications for SAE J300 revised January 2015 requirements for a SAE 20, 30, 40, 50, or 60 monograde engine oil, and has a TBN of 5 to 200 mg KOH/g, as determined by ASTM D2896.