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 sulphonate (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 present invention relates to a Zinc free High Performance bearing oil composition for Lubrication of Bearings, Gears & Allied Equipments in Wire Rod Mill (WRM) for Steel Plants.

Disclosed herein is a mineral base oil satisfying the following requirements (I) to (V): (I): a kinematic viscosity at 100 C. is 2 mm.sup.2/s or more and less than 7 mm.sup.2/s; (II): a viscosity index is 100 or more; (III): a temperature gradient |*| of complex viscosity between two points of 10 C. and 25 C. is 60 Pa.Math.s/ C. or less as measured with a rotary rheometer under conditions at an angular velocity of 6.3 rad/s and a strain amount of 0.1 to 100%; (IV): a content ratio [R1/R2] of a monocyclo paraffin component (R1) to a dicyclo to hexacyclo paraffin component (R2) is 0.70 or less by a volume ratio as measured in accordance with ASTM D2786; and (V): a % C.sub.A is less than 1.0.

Disclosed are lubricant compositions with improved oxidation stability which are prepared with Group III base stocks comprising greater than or equal to about 90 wt. % saturated hydrocarbons (saturates); a viscosity index from 120 to 145; a unique ratio of molecules with multi-ring naphthenes to single ring naphthenes (2R+N/1RN); a unique ratio of branched carbons to straight chain (BC/SC) carbons; and a unique ratio of branched carbons to terminal chain (BC/TC) carbons.

Disclosed are lubricant compositions with improved oxidation stability which are prepared with Group III base stocks comprising greater than or equal to about 90 wt. % saturated hydrocarbons (saturates); a viscosity index from 120 to 145; a unique ratio of molecules with multi-ring naphthenes to single ring naphthenes (2R+N/1RN); a unique ratio of branched carbons to straight chain (BC/SC) carbons; and a unique ratio of branched carbons to terminal chain (BC/TC) carbons.

Disclosed are lubricant compositions prepared with Group III base stocks comprising greater than or equal to about 90 wt. % saturated hydrocarbons (saturates); a viscosity index from 120 to 145; a unique ratio of molecules with multi-ring naphthenes to single ring naphthenes (2R+N/1RN); and a unique ratio of branched carbons to straight chain (BC/SC) carbons; a unique ratio of branched carbons to terminal carbons (BC/TC); and unique MRV behavior as a function of base stock naphthene ratio (2R+N/1RN).

Disclosed are lubricant compositions prepared with Group III base stocks comprising greater than or equal to about 90 wt. % saturated hydrocarbons (saturates); a viscosity index from 120 to 145; a unique ratio of molecules with multi-ring naphthenes to single ring naphthenes (2R+N/1RN); and a unique ratio of branched carbons to straight chain (BC/SC) carbons; a unique ratio of branched carbons to terminal carbons (BC/TC); and unique MRV behavior as a function of base stock naphthene ratio (2R+N/1RN).

The disclosed technology provides a lubricating composition and a method of lubricating an internal combustion engine where the lubricating composition contains an oil of lubricating viscosity, one or more metal-containing, sulfur-free, alkyl-phenol based detergents, an alkaline earth metal sulfonate detergent, a polyisobutenyl succinimide dispersant, and a dispersant viscosity modifier having a number average molecular weight of at least 20,000. The lubricating composition of the present invention can be formulated to have lower HTHS viscosity, and reduced phosphorous content, while providing protection against adhesive wear.

An oleaginous nanoparticle dispersion of nanoparticles having a core of an organic base material immobilized within a surfactant layer, the use thereof as a low ash, or ash-free source of TBN in lubricating oil compositions, and lubricating oil compositions formulated with such oleaginous nanoparticle dispersions.

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.