A method minimizes power loss in a direct injection diesel engine by adding a copolymer to a diesel fuel composition. The copolymer contains, in a copolymerized form, (A) maleic anhydride, (B) an α-olefin having from 12 to 30 carbon atoms, (C) optionally an additional aliphatic or cycloaliphatic olefin which has at least 4 carbon atoms and is different from monomer (B), and (D) optionally an additional copolymerizable monomer other than monomers (A), (B) and (C). Monomer (D) can be a vinyl ester, a vinyl ether, a (meth)acrylic ester of an alcohol having at least 5 carbon atoms, an allyl alcohol or an ester thereof, a N-vinyl compound, an ethylenically unsaturated aromatic, an α,β-ethylenically unsaturated nitrile, a (meth)acrylamide, or an allylamine. Anhydride functionalities present in the copolymer are partly reacted with at least one compound (E) comprising an alcohol group and/or an amino group, and the anhydride functionalities present are hydrolyzed.

A method minimizes power loss in a direct injection diesel engine by adding a copolymer to a diesel fuel composition. The copolymer contains, in a copolymerized form, (A) maleic anhydride, (B) an α-olefin having from 12 to 30 carbon atoms, (C) optionally an additional aliphatic or cycloaliphatic olefin which has at least 4 carbon atoms and is different from monomer (B), and (D) optionally an additional copolymerizable monomer other than monomers (A), (B) and (C). Monomer (D) can be a vinyl ester, a vinyl ether, a (meth)acrylic ester of an alcohol having at least 5 carbon atoms, an allyl alcohol or an ester thereof, a N-vinyl compound, an ethylenically unsaturated aromatic, an α,β-ethylenically unsaturated nitrile, a (meth)acrylamide, or an allylamine. Anhydride functionalities present in the copolymer are partly reacted with at least one compound (E) comprising an alcohol group and/or an amino group, and the anhydride functionalities present are hydrolyzed.

Lubricating compositions containing a phosphorus-containing salt of an acylated ethylene-α-olefin polymer substituted with an aliphatic polyamine having at least one primary or secondary amine, the lubricating composition having a total phosphorus content in an amount of 200 ppm to 600 ppm by weight of the lubricating composition. The phosphorus-containing salt additive described herein can be used as an anti-wear agent in lubricating composition for diesel engines.

Lubricating compositions containing a phosphorus-containing salt of an acylated ethylene-α-olefin polymer substituted with an aliphatic polyamine having at least one primary or secondary amine, the lubricating composition having a total phosphorus content in an amount of 200 ppm to 600 ppm by weight of the lubricating composition. The phosphorus-containing salt additive described herein can be used as an anti-wear agent in lubricating composition for diesel engines.

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.

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.

The instant disclosure relates to a lubricant composition having an oil of lubricating viscosity, a polymeric surfactant compound that is an acylated polymer having a number average molecular weight of about 500 to about 50,000 where the polymer comprises a branched olefin having from 8 to 30 carbon atoms. The acylated polymer can further be reacted with an amine or alcohol to form an amide, imide, ester or combinations thereof. The present disclosure further relates to lubricant compositions that exhibit good dispersancy and viscometric performance.

The present disclosure describes lubricant compositions effective to minimize average engine sludge through selection of lubricant additives that control the total nitrogen as well as the origin of the nitrogen in the lubricant composition. In aspects, the lubricant compositions herein include at least a base oil of lubricating viscosity, a dispersant system, and at least one antioxidant.

The present invention provides a hydraulic fluid comprising: (a) 40 to 2000 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, each of R.sup.2 and R.sup.3 is independently hydrogen or a hydrocarbyl group comprising 1 to 20 carbon atoms, R.sup.4 is —NR.sup.5R.sup.6 or —OR.sup.7, each of R.sup.5 and R.sup.6 is independently an aryl group comprising 6 to 14 carbon atoms, optionally substituted with one or more hydrocarbyl groups comprising 1 to 20 carbon atoms, R.sup.7 is a hydrocarbyl group comprising 1 to 20 carbon atoms, and in each of said hydrocarbyl groups containing 2 or more carbon atoms, the carbon chain may, independently, optionally be interrupted by one or more ether groups; (b) 0.1 to 1% by weight of an ashless dispersant; and (c) a major amount of a base oil.

The present invention provides, among other things, a process to produce a low molecular weight dispersant polymethacrylate polymer (“LMWDPMA”), and the LMWDPMA itself, along with the use of the LMWDPMA in a lubricating composition, as well as a method for lubricating an internal combustion engine as disclosed herein.