The invention relates to a method for lowering the content of polycyclic aromatic hydrocarbons (PAH) in a used lubricant composition, in which said used lubricant composition passes over activated carbon, said method not comprising a solvent extraction step.

An aspect of the present invention relates to a refrigerating machine oil with a kinematic viscosity at 100° C. of 0.5 mm.sup.2/s or more and 1.5 mm.sup.2/s or less, a 90% distillation temperature in gas chromatography distillation of 280° C. or more and less than 360° C., and an aniline point of 70° C. or more.

Compositions, methods, systems, and applications herein are directed to lubricant blends that balance solubility and viscosity of a refrigerant, where in some cases the lubricant blends herein help reduce solubility of a refrigerant. A lubricant blend includes a mixture of two or more different types of lubricants to reduce refrigerant solubility.

(1) A cylinder lubricating oil composition for a crosshead diesel engine, the composition having: a sulfated ash content of 2.0 to 5.5 mass %; a base number of 15 to 45 mgKOH/g; and an autoignition temperature of no less than 262° C. (2) A cylinder lubricating oil composition for a crosshead diesel engine, comprising: a lubricant base oil; (B) a Ca sulfonate detergent having a base number of no less than 10 mgKOH/g and less than 60 mgKOH/g; (C) a Ca phenate detergent having a base number of 55 to 200 mgKOH/g; (D′) an amine antioxidant; and (E′) a zinc dithiophosphate, wherein the composition has a base number of no less than 15 mgKOH/g and less than 120 mgKOH/g.

A shock absorber that includes a pressure tube that defines a working chamber having a hydraulic fluid located therein; a piston assembly positioned in the working chamber, and dividing the working chamber into an upper working chamber and a lower working chamber; and a piston rod engaged with the piston assembly that moves the piston assembly in the working chamber, wherein the hydraulic fluid includes a primary oil, a secondary oil, and an additive package, the secondary oil includes at least a gas-to-liquid oil in an amount that ranges between 4.0 wt % to 10.0 wt % relative to a total amount of the hydraulic fluid, and the hydraulic fluid includes a flash point of at least 174 degrees C.

A base stock having at least 90 wt. % saturates, an amount and distribution of aromatics, as determined by ultra violet (UV) spectroscopy, including an absorptivity between 280 and 320 nm of less than 0.015 l/gm-cm, a viscosity index (VI) from 80 to 120, and having a cycloparaffin performance ratio greater than 1.05 and a kinematic viscosity at 100 C. between 4 and 6 cSt. A base stock having at least 90 wt. % saturates, an amount and distribution of aromatics, as determined by UV spectroscopy, including an absorptivity between 280 and 320 nm of less than 0.020 l/gm-cm, a viscosity index (VI) from 80 to 120, and having a cycloparaffin performance ratio greater than 1.05 and a kinematic viscosity at 100 C. between 10 and 14 cSt. A lubricating oil having the base stock as a major component, and one or more additives as a minor component. Methods for improving oxidation performance and low temperature performance of formulated lubricant compositions through the compositionally advantaged base stock.

A lubricant composition is provided which comprises a base oil and hydroxytyrosol and/or esters thereof. Also provided is a lubricant composition in which the esters have a solubility in the base oil at 25 C. of at least 0.1 g/l. Further provided is a lubricant composition in which the esters are at least partly carboxylic acid esters comprising esters of hydroxytyrosol and C.sub.2-10 carboxylic acids.

A lubricating composition suited for use in lubricating a driveline device includes an oil of lubricating viscosity and a compound comprising a polyolefin-substituted bridged hydroxyaromatic compound or metal salt thereof, wherein the polyolefin is derived from a isobutylene having a number average molecular weight of 150 to 800.

Compositions, methods, systems, and applications herein are directed to lubricant blends that balance solubility and viscosity of a refrigerant, where in some cases the lubricant blends herein help reduce solubility of a refrigerant. A lubricant blend includes a mixture of two or more different types of lubricants to reduce refrigerant solubility.

A lubricating composition suited to use in lubricating an internal combustion engine includes an oil of lubricating viscosity and a compound comprising a polyolefin-substituted bridged hydroxyaromatic compound or metal salt thereof, wherein the polyolefin is derived from a isobutylene having a number average molecular weight of 150 to 800.