The present invention relates to a lubricating oil composition to be used for internal combustion engines, the lubricating oil composition containing a base oil (A), an imide compound (B) that is at least one selected from a succinic acid monoimide (B1) represented by the general formula (b-1) and a succinic acid bisimide (B2) represented by the foregoing general formula (b-2), a metal-based detergent (C) that is at least one selected from a metal sulfonate (C1) having a branched alkyl group and a metal phenate (C2) having a branched alkyl group, and a zinc dithiophosphate (D), wherein the content of a phosphorus atom derived from the component (D) is less than 800 ppm by mass on the basis of the total amount of the lubricating oil composition; and a method for producing the same. The present invention is able to provide a lubricating oil composition in which even in the case where the content of a phosphorus atom derived from an anti-wear agent is reduced, it is possible to reveal excellent wear resistance in an internal combustion engine and a high friction coefficient in a wet clutch; and a method for producing the same.

Provided is a lubricating oil composition capable of revealing fuel consumption reducing properties due to a friction reducing effect within a short period of time while having excellent fuel consumption reducing properties, specifically a lubricating oil composition of the present invention includes a base oil, a molybdenum dithiocarbamate, a calcium detergent, a magnesium detergent, and a boron-free succinimide, wherein the content of the molybdenum dithiocarbamate as converted into a molybdenum atom is 1,200 ppm by mass or less on a basis of the whole amount of the composition; the content of the boron-free succinimide as converted into a nitrogen atom is less than 1,200 ppm by mass on a basis of the whole amount of the composition; and a mass ratio of the molybdenum atom (Mo) to a magnesium atom (Mg) of the magnesium detergent [Mo/Mg] is 0.1 or more.

Provided is a lubricating oil composition capable of revealing fuel consumption reducing properties due to a friction reducing effect within a short period of time while having excellent fuel consumption reducing properties, specifically a lubricating oil composition of the present invention includes a base oil, a molybdenum dithiocarbamate, a calcium detergent, a magnesium detergent, and a boron-free succinimide, wherein the content of the molybdenum dithiocarbamate as converted into a molybdenum atom is 1,200 ppm by mass or less on a basis of the whole amount of the composition; the content of the boron-free succinimide as converted into a nitrogen atom is less than 1,200 ppm by mass on a basis of the whole amount of the composition; and a mass ratio of the molybdenum atom (Mo) to a magnesium atom (Mg) of the magnesium detergent [Mo/Mg] is 0.1 or more.

An automatic transmission oil composition includes 80 to 85 wt % of a base oil, 1 to 5 wt % of metallocene polyalphaolefin, 1 to 5 wt % of a detergent-dispersant, 0.01 to 0.03 wt % of a trinuclear molybdenum-based dialkyldithiocarbamate friction modifier, 3 to 10 wt % of a viscosity modifier, and 3 to 5 wt % of an anti-wear additive. The automatic transmission oil composition is prepared by mixing base oil with metallocene polyalphaolefin and a trinuclear molybdenum-based dialkyldithiocarbamate friction modifier at specific mixing ratios, whereby the dynamic friction coefficient can be maintained at an equivalent level and the metal friction coefficient can be reduced, thus improving the power transfer efficiency between transmission metals and fuel economy (an improvement of 1.5% or more), increasing durability, and minimizing energy loss.

The invention provides a method of lubricating a compression-ignition internal combustion engine with a maximum laden mass over 2,700 kg comprising supplying to the engine a lubricating composition comprising: an oil of lubricating viscosity, a 300 TBN or higher alkaline earth metal sulphonate detergent having a metal ratio of 10 to 40, 0.1 wt % to 4 wt % of a borated polyisobutylene succinimide dispersant, wherein the polyisobutylene from which the borated polyisobutylene succinimide is derived has a number average molecular weight of 550 to 1150, and 0.1 wt % to 6 wt % of a polyisobutylene succinimide, wherein the polyisobutylene from which polyisobutylene succinimide is derived has a number average molecular weight of 1550 to 2500, 0 wt % to 0.2 wt % of a phenolic based detergent, wherein the total amount of soap delivered by the alkaline earth metal sulphonates (typically calcium sulphonate) is 0.4 to 1 wt % of the lubricating composition, and wherein the lubricating composition has a sulphated ash content of not more than 1.5 wt %.

The invention provides a method of lubricating a compression-ignition internal combustion engine with a maximum laden mass over 2,700 kg comprising supplying to the engine a lubricating composition comprising: an oil of lubricating viscosity, a 300 TBN or higher alkaline earth metal sulphonate detergent having a metal ratio of 10 to 40, 0.1 wt % to 4 wt % of a borated polyisobutylene succinimide dispersant, wherein the polyisobutylene from which the borated polyisobutylene succinimide is derived has a number average molecular weight of 550 to 1150, and 0.1 wt % to 6 wt % of a polyisobutylene succinimide, wherein the polyisobutylene from which polyisobutylene succinimide is derived has a number average molecular weight of 1550 to 2500, 0 wt % to 0.2 wt % of a phenolic based detergent, wherein the total amount of soap delivered by the alkaline earth metal sulphonates (typically calcium sulphonate) is 0.4 to 1 wt % of the lubricating composition, and wherein the lubricating composition has a sulphated ash content of not more than 1.5 wt %.

An automatic transmission oil composition includes 80 to 85 wt % of a base oil, 1 to 5 wt % of metallocene polyalphaolefin, 1 to 5 wt % of a detergent-dispersant, 0.01 to 0.03 wt % of a trinuclear molybdenum-based dialkyldithiocarbamate friction modifier, 3 to 10 wt % of a viscosity modifier, and 3 to 5 wt % of an anti-wear additive. The automatic transmission oil composition is prepared by mixing base oil with metallocene polyalphaolefin and a trinuclear molybdenum-based dialkyldithiocarbamate friction modifier at specific mixing ratios, whereby the dynamic friction coefficient can be maintained at an equivalent level and the metal friction coefficient can be reduced, thus improving the power transfer efficiency between transmission metals and fuel economy (an improvement of 1.5% or more), increasing durability, and minimizing energy loss.

A constant velocity joint having a boot constructed from a thermoplastic polyether ester as the boot material. The boot includes a lubricating grease composition for lubricating the constant velocity joint, the lubricating grease composition comprising calcium lignin sulfonate.

A lubricant composition of an oil of lubricating viscosity, an ashless condensation reaction product of an olefin polymer, having a number average molecular weight of 2,000 to 70,000, comprising carboxylic acid or equivalent functionality grafted onto the polymer backbone, with a monoamine or a polyamine often having a single primary amino group; a succinimide dispersant; and an overbased metal detergent, in an amount such that the total base number of the lubricant composition is less than 6.5, exhibits good sludge prevention performance in a gasoline engine.

A lubricant composition of an oil of lubricating viscosity, an ashless condensation reaction product of an olefin polymer, having a number average molecular weight of 2,000 to 70,000, comprising carboxylic acid or equivalent functionality grafted onto the polymer backbone, with a monoamine or a polyamine often having a single primary amino group; a succinimide dispersant; and an overbased metal detergent, in an amount such that the total base number of the lubricant composition is less than 6.5, exhibits good sludge prevention performance in a gasoline engine.