Novel uses of copolymers for removing and/or reducing the level of deposits in the fuel system and/or injection system of direct injection diesel and/or gasoline engines are provided. What is provided is the use of particular copolymers as fuel additive or lubricant additive; to processes for preparation of such additives, and fuels and lubricants added therewith, such as, more particularly, as a detergent additive; to use of these copolymers for reducing the level of or preventing deposits in the fuel systems and especially the injection systems of direct injection diesel engines, especially in common rail injection systems, for reducing the fuel consumption of direct injection diesel engines, especially of diesel engines with common rail injection systems, and for minimizing power loss in direct injection diesel engines, especially in diesel engines with common rail injection systems; and as an additive for gasoline fuels, especially for operation of DISI engines.

A liquid hydrocarbon marine fuel oil includes a marine distillate fuel or a heavy oil or a blend thereof containing an additive combination including: (A) a polyalkenyl-substituted carboxylic acid or anhydride, and (B) a metal hydrocarbyl-substituted hydroxybenzoate and/or sulfonate detergent,
where the mass:mass ratio of (A) to (B) is in the range of 20:1 to 1:20 and the treat rate of the additive combination is in the range of 5 to 10000 ppm by mass.

Disclosed are cloud point depressants and methods of making and using them. The disclosed cloud point depressants comprise copolymers of an unsaturated anhydride polymerized with alkyl α-olefins and then contacted with a phenyl alkyl alcohol or alkyl phenol alkoxylate, fatty alcohol and primary or secondary fatty amine to provide a cloud depressant reaction product. When the disclosed reaction products are added to middle distillate fuels or blends of middle distillate fuels with biodiesel, the cloud point depressants inhibit the precipitation of waxes and/or biowaxes in the fuels and the fuels exhibit reduced precipitation, gelling, and/or crystallization when subjected to low or cold temperatures.

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.

Fouling and/or asphaltene agglomeration (or flocculation) in midstream processes and transportation and in upstream transportation of a hydrocarbon oil is reduced by providing in the oil an additive combination including; (A) a polyalkenyl-substituted carboxylic acid or anhydride, and (B) a metal detergent system comprising a hydrocarbyl-substituted hydroxybenzoate metal salt or a hydrocarbyl-substituted sulfonate metal salt or a mixure of both salts or a complex thereof,
where the mass:mass ratio of (A) to (B) is in the range of 20:1 to 1:20 and the treat rate of the additive is in the range of 5 to 10000 ppm by mass.

A method for minimizing power loss, reducing a fuel consumption and/or for reducing and/or avoiding deposits in a fuel system in the direct injection diesel engines. The method contains adding a copolymer to a fuel composition, wherein the copolymer contains, in a copolymerized form: (A) an ethylenically unsaturated mono- or dicarboxylic acid or a derivative thereof, (B) an -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 monomers other than monomers (A), (B) and (C), anhydride or carboxylic acid 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 in the copolymer are hydrolysed and/or carboxylic ester functionalities present in the copolymer are partly hydrolyzed.

The present invention relates to a copolymer obtainable by copolymerization of (A) at least one unsaturated dicarboxylic acid or derivatives thereof, (B) at least one -olefin having from at least 6 up to and including 20 carbon atoms, (C) optionally at least one C.sub.3- to C.sub.20-alkyl ester of acrylic acid or methacrylic acid or a mixture of such alkyl esters and (D) optionally one or more further copolymerizable monomers other than monomers (A), (B) and (C), with a molar incorporation ratio of (A):(B):(C):(D) of 1:0.5 to 2.0:0 to less than 0.5:0 to 0.1 followed by the reaction with at least one dialkylamine (E), where the two alkyl radicals in the at least one dialkylamine (E) are independently alkyl radicals having at least 17 up to 30 carbon atoms.

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.

A method making fuel oil from refining residuals. Refining residuals are mixed with a diluent and an additive. Preferred diluents include diesel and reformed naphtha and combinations thereof. The additive is believed to be a cross-linked cyclic anhydride copolymer having an intrinsic viscosity (limiting viscosity, ) of between about 0.10 and 3.0 deciliters per gram and an average molecular weight between about 3,000 and 3,000,000. The additive includes excess aromatic hydrocarbons and a surfactant. In the preferred embodiment, the diluent and the residuals are mixed together in a ratio of about 3:1, by weight. The additive is introduced to this mixture in the amount of about 0.10 to 0.25 percent by weight. The components are thoroughly combined to yield a fuel oil having a viscosity that is about 25 to as much as about 70 percent lower than the viscosity of the same residual/diluent mixture lacking the additive.

The present invention relates to a copolymer obtainable by copolymerization of

(A) at least one unsaturated dicarboxylic acid or derivatives thereof,
(B) at least one -olefin having from at least 6 up to and including 20 carbon atoms,
(C) optionally at least one C.sub.3- to C.sub.20-alkyl ester of acrylic acid or methacrylic acid or a mixture of such alkyl esters and
(D) optionally one or more further copolymerizable monomers other than monomers (A), (B) and (C),
with a molar incorporation ratio of (A):(B):(C):(D) of 1:0.5 to 2.0:0 to less than 0.5:0 to 0.1
followed by the reaction with at least one dialkylamine (E), where the two alkyl radicals in the at least one dialkylamine (E) are independently alkyl radicals having at least 17 up to 30 carbon atoms.