Provided is a grease containing a base oil and a hydrophilic nanofiber, the hydrophilic nanofiber having a thickness (d) of 0.01 to 500 nm being dispersed therein. The grease is low in an environmental load and excellent in safety on the human body and also has an appropriate worked penetration and has a high dropping point, and therefore, it is also excellent in heat resistance.

Lubricant compositions comprising a base oil, one or more antioxidants selected from a group consisting of N--naphthyl-N-phenylamine antioxidants and diphenylamine antioxidants; and a sulfur-containing additive comprising up to seven carbon atoms exhibit outstanding oxidative stability and non-corrosion properties. The N--naphthyl-N-phenylamine antioxidants plus diphenylamine antioxidants in total may be present from about 0.2 wt % to about 0.8 wt %, based on the total weight of the lubricant composition. The sulfur provided by the sulfur-containing additive may be present from about 50 ppm to about 1000 ppm by weight, based on the total weight of the lubricant composition.

A quaternary ammonium compound of formula (I):

##STR00001##

wherein R.sup.0, R.sup.1, R.sup.2 and R.sup.3 is each independently an optionally substituted hydrocarbyl group, X is a linking group, R.sup.4 is an optionally substituted alkylene group, R.sup.5 is hydrogen or an optionally substituted alkyl, alkenyl or aryl group, and n is 0 or a positive integer, provided that n is not 0 when R.sup.5 is hydrogen.

The present disclosure generally relates to a lubricating oil composition having a sulfur content of up to 0.4 wt. % and a sulfated ash content of up to 0.6 wt. %, as determined by ASTM D874, comprising: a major amount of base oil; at least 0.02 wt. % of triazole compound; less than about 1.3 wt. % of a diphenylamine antioxidant; and at least 900 ppm of molybdenum from a molybdenum containing compound; wherein the lubricating oil composition is essentially free of ZnDTP. Also provided are methods for reducing wear and copper corrosion in an engine which is equipped with a diesel particulate filter (DPF) or a gasoline particulate filter (GPF) after treatment device system.

A lithium-based thickener is contained in an amount of 6 to 14 wt % based on a total weight of a grease composition. The amount of the lithium-based thickener contained in the grease composition can be reduced by about half compared to a conventional thickener, thus effectively increasing viscosity of base oil and reducing fluidity.

A quaternary ammonium compound of formula (I): (I) wherein R.sup.0, R.sup.1, R.sup.2 and R.sup.3 is each independently an optionally substituted hydrocarbyl group, X is a linking group, R.sup.4 is an optionally substituted alkylene group, R5 is hydrogen or an optionally substituted alkyl, alkenyl or aryl group, and n is 0 or a positive integer, provided that n is not 0 when R5 is hydrogen.

##STR00001##

Certain embodiments of the invention provide a lubricating oil composition comprising a lubricating oil base stock and a compound of formula (I): ##STR00001##
or a salt thereof, wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 have any of the values defined in the specification, as well as methods of use thereof.

A quaternary ammonium salt of formula (I): (I) where in X is a linking group; Y is O, NH or NR.sup.1 wherein R.sup.1is H or an optionally substituted hydrocarbyl group; Q.sup. is a moiety that includes a quaternary ammoniumcation; A.sup. is an anion; R.sup.2 is an optionally substituted alkylene group; R.sup.3 is hydrogen or an optionally substituted hydrocarbyl group; and n is 0 or a positive integer; provided that n is not 0 when R.sup.3 is hydrogen.

##STR00001##

Provided is a lubricating oil composition containing a base oil (A) and a viscosity index improver (B) and satisfying the following requirements (I) and (II):

Requirement (I): a kinematic viscosity at 80 C., V.sub.80 of the lubricating oil composition is 11.5 mm.sup.2/s or less;

Requirement (II): a ratio [V.sub.80/T.sub.80] of a kinematic viscosity at 80 C., V.sub.80 (m.sup.2/s) to an oil film thickness measured at a sliding speed of 2.0 m/s, a maximum Hertz pressure of 0.8 GPa, and an oil temperature of 80 C., T.sub.80 (nm) of the lubricating oil composition is less than 0.105 ((m.sup.2/s)/nm).

The lubricating oil composition is excellent in fuel saving properties and anti-wear properties even when it is used in a temperature environment of around 80 C. which is assumed to fall within a range where an engine is practically used.

A metalworking fluid is disclosed. The fluid comprises an oleaginous component, an aqueous component, and a surfactant dispersed in the aqueous component. The metalworking fluid is substantially free from defoamers or anti-foam compounds.