The present disclosure relates to methods of lubricating an electric or a hybrid-electric transmission using a lubricant including a solvent system with a blend of one or more base oils with a branched diester and one or more poly(meth)acrylate copolymers, transmissions therefor, and lubricating compositions suitable for such applications that exhibit good lubricant properties, good electrical properties, and good cooling efficiency at the same time.

A water-soluble metalworking fluid composition and a method of using the same. The water-soluble metalworking fluid composition has the components (A), (B), and (C), where (A) is a fatty acid having a carbon atom number of 9-11, (B) is an unsaturated fatty acid having a carbon atom number of 16-22, and (C) is a polymeric fatty acid having an acid value of 10-200 mgKOH/g. (A) is 1-20 mass %, (B) is 30-60 mass %, and (C) is 35-55 mass %, based on the total amount of the components (A), (B) and (C). The water-soluble metalworking fluid composition maintains the workability while improving the mechanical fouling.

A method for utilizing a lubricating oil composition in which the content of a metal-based cleaning agent (X) having a base value of 100 mgKOH/g or less is 630 mass ppm or less in terms of metal atoms, and the content of sulfated ash is 1.5 mass % or less. The method includes measuring at least one physical property value among the capacitance and the dielectric constant of the lubricating oil composition while using the lubricating oil composition, and evaluating the progress of degradation of the lubricating oil composition.

The present invention provides a hydraulic fluid comprising: (a) 40 to 150 ppm by weight in terms of nitrogen content of a corrosion inhibiting agent which is one or more compounds of formula (I):

##STR00001## and/or tribologically acceptable salts thereof, wherein in formula (I): each R.sup.1 is independently a hydrocarbyl group comprising 1 to 10 carbon atoms, x is 0 to 4, and R.sup.2 is hydrogen or a hydrocarbyl group containing 1 to 10 carbon atoms; (b) 1500 to 4000 ppm by weight of an ashless nitrogen-containing dispersant; and (c) a major amount of a base oil.

A lubricant composition that comprises a hydrocarbon base oil, a polar viscosity improver; and an esterified polyalkylene glycol: R.sup.1[O(R.sup.2O).sub.n(R.sup.3O).sub.m(C═O)R.sup.4].sub.p, wherein R.sup.1 is a linear alkyl having 1 to 18 carbon atoms, a branched alkyl having 4 to 18 carbon atoms or an aryl with 6 to 30 carbon atoms; R.sup.2O is an oxypropylene moiety derived from 1, 2-propylene oxide; R.sup.3O is an oxybutylene moiety derived from butylene oxide, wherein R.sup.2O and R.sup.3O are in a block or a random distribution; R.sup.4 is a linear alkyl with 1 to 18 carbon atoms, a branched alkyl with 4 to 18 carbon atoms or an aryl with 6 to 18 carbon atoms; n and m are each independently integers ranging from 0 to 20 wherein n+m is greater than 0, and p is an integer from 1 to 4. The lubricant composition may have a viscosity index of at least 150, a kinematic viscosity at 100° C. from 2 to 5 centistokes and a kinematic viscosity at −20° C. of at most 600 centistokes.

A lubricating oil composition including a major amount of a base oil, one or more calcium-containing detergents to provide at least 1000 ppmw of calcium, and one or more silicon-containing compound(s) to provide at least 50 ppmw of silicon to the lubricating oil composition, all based on the total weight of the lubricating oil composition, wherein a ratio of ppmw of silicon provided by the one or more silicon-containing compound(s) to the lubricating oil composition to the ppmw of calcium provided by the one or more calcium-containing detergent(s) to the lubricating oil composition is from 0.02 to 1. Methods of using these compositions and silicon-containing detergents are also described.

The present invention relates to a hydraulic fluid composition containing a base oil (A), an antioxidant (B) including an amine-based antioxidant (B1) and a phenol-based antioxidant (B2), and a succinimide-based compound (C), wherein the hydraulic fluid composition satisfies the following requirement (I); and is to be used for hydraulic equipment which is equipped with at least one of a wet type brake and a wet type clutch and which is selected from a construction machinery, a general industrial machinery, and a power generator, and in which a working pressure is 30 MPa or more. The hydraulic fluid composition is not only excellent in wear resistance and an effect for suppressing the sludge formation but also excellent in a braking performance or a clutch performance, even when used under a high-pressure condition. Requirement (I): A static friction coefficient (μ.sub.s) after 1,000 cycles, as measured in conformity with the SAE No. 2 test described in JCMAS P 047:2004, is 0.100 to 0.162.

Use of a liquid fuel composition in an internal combustion engine, the internal combustion engine containing a lubricating composition for lubricating said internal combustion engine, wherein the liquid fuel composition comprises at least one nitrogen-containing detergent additive, for the purpose of reducing engine wear caused by the presence of soot in the lubricating composition.

A lubricating composition comprising a base oil and one or more additives, wherein the composition has: a sulphated ash content (according to ASTM D 874) of at least 0.4 wt % and at most 1.0 wt. %, by weight of the lubricating composition; a total base number (TBN) value (according to ASTM D 2896) of at least 4.0 mg KOH/g and at most 12 mg KOH/g; a total aromatics content contributed by the base oil in the range from 1 wt % to 30 wt %, by weight of the lubricating composition; and a sulphur content contributed by the base oil of 0.4 wt % or less, by weight of the lubricating composition; and wherein the base oil comprises a blend of (i) a first base oil which is a mineral base oil selected from an API Group I mineral base oil and an API Group II mineral base oil, and mixtures thereof, and (ii) a second base oil selected from an API Group II base oil and an API Group III base oil, preferably wherein the first base oil belongs to a different API group to that of the second base oil.

The present invention provides a lubricant composition comprising a base oil of lubricating viscosity, wherein the base oil comprises an ether base stock of formula (A), where: R.sub.a and R.sub.b are aliphatic hydrocarbyl groups and may be the same or different; the lubricant composition further comprising at least one aminic anti-oxidant and at least one phenolic anti-oxidant. In some embodiments, the ether base stock has the formula (1), where: R.sub.1 R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are as defined herein. The lubricant composition may be used for lubricating a surface in an internal combustion engine as well as for improving the fuel economy performance and/or piston cleanliness performance of an engine and/or a vehicle, such as an automotive vehicle associated with an internal combustion engine. ##STR00001##