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 winterized paraffin inhibitor, which is capable of being used for preventing the deposition of paraffins in hydrocarbon streams and capable of withstanding freezing or crystallization at freezing or sub-freezing temperatures, may be formed by adding an oxyalkylated branched aliphatic compound having 12 or more carbons to a high molecular weight aliphatic polymer paraffin inhibitor, the oxyalkylated branched aliphatic compound having 12 or more carbons being produced by the oxyalkylation of the branched aliphatic compound having 12 or more carbon atoms in which the branched aliphatic compound having 12 or more carbon atoms is grafted with a polyether via a ring-opening reaction, wherein the polyether is a polymer of ethylene oxide, propylene oxide, butylene oxide, and combinations thereof.

A fuel oil composition comprising a blended fuel oil having a sulfur content of less than 5000 ppm and an additive wherein the additive is a copolymer comprising maleic anhydride derived units and α-olefin derived units.

An olefin-carboxylic acid copolymer, containing at least one free carboxylic acid side group, or a nitrogen compound quaternized with epoxide in the presence of an olefin-carboxylic acid copolymer, containing at least one free carboxylic acid side group, can be used as a fuel additive or lubricant additive. Processes can be used for preparing additives of this kind and fuels and lubricants additized therewith, such as a detergent additive. These additives, fuels, and lubricants can be used for reduction or prevention of deposits in injection systems of direct injection diesel engines, especially in common rail injection systems; for reduction of fuel consumption of direct injection diesel engines, especially of diesel engines with common rail injection systems; and for minimization of power loss in direct injection diesel engines, especially in diesel engines with common rail injection systems. The additives can also be used for gasoline fuels, especially for operation of DISI engines.

This invention provides a wax inhibitor composition comprising A) the reaction product obtainable by reaction of i) a carboxylic acid containing an optionally substituted cycloaliphatic hydrocarbyl residue with ii) an alkylene polyamine, B) a polymeric wax inhibitor, and C) an organic solvent.

A method for the preparation of a copolymer containing at least one alkyl methacrylate and maleic anhydride having a number average molecular weight of 4000 to 18000 g/mol proceeds by solution polymerization in the presence of a radical initiator.

Embodiments of the invention provide a method of inhibiting precipitation of biodiesel fuel components. The method includes providing a biodiesel fuel composition; providing a copolymer comprising at least first and second polymer units, said first polymer units derived from a carboxylic acid anhydride and said second polymer units derived from an olefin; and blending said copolymer with the biodiesel fuel to form a treated fuel composition. Alternatively, instead of the copolymer, a dialkylene glycol additive can be provided. Embodiments of the invention provide a method of reducing the cold soak filter blocking tendency of a biodiesel fuel composition.

This invention relates to a fuel oil composition, containing a low-sulfur marine diesel having a sulfur content of less than 1 wt. % and (A) at least one ethylene copolymer and (B) at least one comb polymer.

Copolymers comprising C.sub.14 to C.sub.50 olefins and at least two different olefindicarboxylic esters and optionally maleic acid or maleic acid derivatives. The olefindicarboxylic esters are firstly esters with linear C.sub.18- to C.sub.50-alkyl groups and secondly esters with short-chain linear, branched or cyclic alkyl groups, or esters with aromatic groups. The invention further relates to a process for preparing copolymers of this kind and to the use thereof as pour point depressant for crude oil, mineral oil and/or mineral oil products, preferably as pour point depressant for crude oil.

An additive composition for a marine fuel or a heating oil comprising a stabilized colloidal dispersion of catalytic metal particles, a neutral or overbased alkaline earth metal detergent and a carrier fluid miscible with a marine fuel oil, a heavy fuel oil, a marine distillate fuel, and/or a residual fuel oil. Also provided are marine fuel and/or heating oil compositions having the additive composition described above and associated methods and uses.