Abstract: Compositions and methods are disclosed for reducing combustion chamber deposits (CCD) and/or intake valve deposits (IVD) in spark ignition internal combustion engines. A butyrolactam alkoxylate (BLA) and/or a butyrolactam derivative (BLD) of this invention or a mixture with at least one additional compound of this invention is added to a liquid hydrocarbon or liquid hydrocarbon-oxygenate gasoline each in an amount of about 0.0005-0.5 wt % of the gasoline. Preferably the gasoline is unleaded. The preferred additional components include polyethers (PE) and polyisobutylene amine (PIBA).

Abstract: Improved fuel compositions and fuel additive packages are disclosed which serve to increase the combustion efficiency of conventional fuels while reducing the level of CO2 emissions generated upon the combustion of the fuels. The fuels may be essentially water-free hydrocarbon fuels such as gasoline or diesel fuel, or may be in the form of hydrosols. The additive packages of the invention include sorbitan oleate, a polyoxyethylene alcohol, an alkylene glycol, and an amine.

Abstract: A fuel additive for middle distillate fuels is a mixture of at least one methyl, ethyl, propyl or butyl ester of a vegetable oil or a C16-C18 fatty acid, at least one alkyl ether of propylene glycol, a surfactant, and an antioxidant. A fuel additive for gasoline is a mixture of ligroin or toluene/xylene, at least one alkyl ether of propylene glycol, a surfactant, and tertiary amyl methyl ether.

Abstract: The invention relates to fuel additive compositions for internal combustion engines and to fuels that contain the corresponding additives for internal combustion engines. The inventive fuel additive compositions for internal combustion engines have an excellent performance in keeping the inlet system clean and improved viscosity properties, especially at low temperatures.

Abstract: The invention relates to middle distillates having a maximal sulphur content of 0.05 wt. %, which contain fatty acid esters of alkoxylated polyols with at least 3 OH groups (A) and at least one cold-fluidity improving additive (B), whereby said cold-fluidity improving additive contains at least one copolymer of ethylene and one or several ethylenically unsaturated carboxylic acid esters, said copolymer having an ethylene portion of 60 to 90 mole %.

Abstract: The invention provides fuel oils comprising a major proportion of a mixture of

Abstract: Oleophilic polyoxyalkylene monoethers having reduced water affinity are disclosed. The monoethers have a hydrocarbyl residue, a polyoxyalkylene moiety, and a hydroxyl end group. The monoethers contain less than about 6 mole percent of alkoxylated unsaturates, and preferably less than about 5 mole percent of polyoxyalkylene diols. The monoethers offer substantial advantages for fuel compositions, particularly reduced water affinity. By using deposit-control additives based on the monoethers, formulators can offer better fuels for cleaner engines.

Abstract: A method is provided for reducing the vapour pressure (RVP) of a gasoline/alcohol mixture which comprises adding a surfactant composition comprising an alkanolamide, an alkoxylated alcohol and an alkoxylated fatty acid to a gasoline/alcohol mixture.

Abstract: Hydrogenated block copolymers are used as a component in a cold flow additive composition.

Abstract: A fuel additive for use in the treatment of diesel fuels to reduce polluting emissions during the combustion of such fuels wherein the additive composition is formulated to contain mineral seal oil, mineral spirits, a glycol alkyl ether and at least one alkyl aromatic ethoxylated surfactant. It has been found that the fuel additive composition of the invention can be blended with such fuels to dramatically reduce emissions during the combustion of such fuels.

Abstract: The present invention relates to a method of producing a diesel fuel blend having a pre-determined flash-point and a pre-determined increase in cetane number over the stock diesel fuel. Upon establishing the desired flash-point and increase in cetane number, an amount of a first oxygenate with a flash-point less than the flash-point of the stock diesel fuel and a cetane number equal to or greater than the cetane number of the stock diesel fuel is added to the stock diesel fuel in an amount sufficient to achieve the pre-determined increase in cetane number. Thereafter, an amount of a second oxygenate with a flash-point equal to or greater than the flash-point of the stock diesel fuel and a cetane number greater than the cetane number of the stock diesel fuel is added to the stock diesel fuel in an amount sufficient to achieve the pre-determined increase in cetane number.

Abstract: This invention relates to a water blended fuel composition made by combining: (i) a normally liquid hydrocarbon fuel; (ii) water; and (iii) a nitrogen-free surfactant. The fuel composition may be used as the fuel for use in an open flame burning apparatus or in an internal combustion engine.

Abstract: A fuel additive composition comprising: a) a Mannich condensation product of (1) a high molecular weight alkyl-substituted hydroxyaromatic compound (2) an amine having the formula:  wherein A is CH or nitrogen, R1, R2, R3 are independently hydrogen or lower alkyl of 1 to about 6 carbon atoms and each R2 and R3 is independently selected in each —CR2R3— unit, and x is an integer from 1 to about 6; and (3) an aldehyde, wherein the respective molar ratio of reactants (1), (2), and (3) is 1:0.1-2:0.1-2; b) a hydrocarbyl-terminated poly(oxyalkylene) monool; and c) a carboxylic acid as represented by the formula: R4(COOH)y  or anhydride thereof, wherein R4 represents a hydrocarbyl group having about 2 to about 50 carbon atoms, and y represents an integer of 1 to about 4.

Abstract: A method of improving the compatibility of a fuel additive composition comprising blending together the following components: a) a Mannich condensation product of (1) a high molecular weight alkyl-substituted hydroxyaromatic compound, (2) an amine having the formula:  wherein A is CH or nitrogen, R1, R2, R3 are independently hydrogen or lower alkyl of 1 to about 6 carbon atoms and each R2 and R3 is independently selected in each —CR2R3— unit, and x is an integer from 1 to about 6;  and (3) an aldehyde, wherein the respective molar ratio of reactants (1), (2), and (3) is 1:0.1-2:0.1-2; b) a hydrocarbyl-terminated poly(oxyalkylene) monool; c) a carboxylic acid as represented by the formula: R4(COOH)y  wherein R4 represents a hydrocarbyl group having about 2 to about 50 carbon atoms, and y represents an integer of 1 to about 4; and d) an anhydride selected from the group consisting of succinic, glutaric, phthalic, and alkyl anhydrides.

Abstract: Fuel-water emulsions in which an alkoxylated, preferably an ethoxylated, polyisobutene is used as an emulsifier are described. Stable emulsions, in particular of diesel-water mixtures, which have advantageous properties when used as fuel in internal combustion engines can be prepared in this manner.

Abstract: A fuel composition for a combustion engine that is treated with a hybrid molecule that is balanced into a polymer by ethoxylation, the result being a commercially viable fuel that is delivered to the point of combustion in the best possible condition with least resistance.

Abstract: Novel clean fuels comprising selected nonlinear long chain saturated primary monohydric/dihydric alcohol derivatives and mixtures thereof; novel diols and/or diol derivatives; and processes for making clean synthetic jet fuels and/or clean synthetic diesel fuels as well as processes for making clean synthetic jet fuels and/or clean synthetic diesel fuels concurrently with making nonlinear alcohols for use by the detergent industry.

Abstract: Compositions and methods are disclosed for reducing combustion chamber deposits (CCD) and/or intake valve deposits (IVD) in spark ignition internal combustion engines. A butyrolactam alkoxylate (BLA) and/or a butyrolactam derivative (BLD) of this invention or a mixture with at least one additional compound of this invention is added to a liquid hydrocarbon or liquid hydrocarbon-oxygenate gasoline each in an amount of about 0.0005-0.5 wt % of the gasoline. Preferably the gasoline is unleaded. The preferred additional components include polyethers (PE) and polyisobutylene amine (PIBA).

Abstract: A mixture suitable as fuel additive and lubricant additive and comprising essentially (A) at least one amine which carries a hydrocarbon radical having an average molecular weight of from 500 to 10,000, (B) at least one hydrocarbon polymer which has an average molecular weight of from 300 to 10,000 and may be present in unhydrogenated or hydrogenated form and (C) at least one conventional carrier oil has a weight ratio of component A to component B of from 80:20 to 60:40.

Abstract: Polyalkene alcohol polyalkoxylates R—(CH2)n—(O—A)m—OH, where R is a polyalkene radical derived from C2- to C30-alkenes and having a number average molecular weight from 300 to 5000, A is an alkylene group of 2 to 8 carbon atoms, m is a number up to 200, with the proviso that the oxygen in the oxyalkylate radical accounts for at least 16.5% by weight of the number average molecular weight of the total molecule I, and n is 0 or 1, are suitable as carrier oils in fuel and lubricant compositions.

Abstract: Oleophilic polyoxyalkylene monoethers having reduced water affinity are disclosed. The monoethers have a hydrocarbyl residue, a polyoxyalkylene moiety, and a hydroxyl end group. The monoethers contain less than about 6 mole percent of alkoxylated unsaturates, and preferably less than about 5 mole percent of polyoxyalkylene diols. The monoethers offer substantial advantages for fuel compositions, particularly reduced water affinity. By using deposit-control additives based on the monoethers, formulators can offer better fuels for cleaner engines.

Abstract: A fuel additive composition comprising: a) a Mannich condensation product of (1) a high molecular weight alkyl-substituted hydroxyaromatic compound wherein the alkyl group has a number average molecular weight of from about 300 to about 5,000 (2) an amine which contains an amino group having at least one active hydrogen atom, and (3) an aldehyde, wherein the respective molar ratio of reactants (1), (2), and (3) is 1:0.1-10:0.

Abstract: A fuel additive composition comprising: a) a Mannich condensation product of (1) a high molecular weight alkyl-substituted hydroxyaromatic compound wherein the alkyl group has a number average molecular weight of from about 300 to about 5,000 (2) an amine which contains an amino group having at least one active hydrogen atom, and (3) an aldehyde, wherein the respective molar ratio of reactants (1), (2), and (3) is 1:0.1-10:0.1-10; b) a hydrocarbyl-terminated poly(oxyalkylene) monool having an average molecular weight of about 500 to about 5,000, wherein the oxyalkylene group is a C2 to C5 oxyalkylene group and the hydrocarbyl group is a C1 to C30 hydrocarbyl group; and c) a carboxylic acid as represented by the formula: R1(COOH)x or anhydride thereof, wherein R1 represents a hydrocarbyl group having about 2 to about 50 carbon atoms, and x represents an integer of 1 to about 4.

Abstract: The present invention relates to a liquid synfuel additive composition which is used as an additive to coal fines to enhance the complete combustion of the coal after turning it into a synthetic fuel. The composition is a chemical change agent in that it converts the coal/composition mix into a different material which, when burned, results in lower noxious emissions. The composition includes a wax, a base for ph adjustment and water.

Abstract: The present invention is directed to a composition for use in a combustion engine either as a fuel additive or as an additive for a crankcase lubricant. The composition may include a polyunsaturated aliphatic or alicyclic compound having at least three, but no more than six, double bonds to improve the combustion process by acting as pseudo-catalyst in the combustion reaction. The composition may further include a derivative of dihydrobenzo-gamma-pyrane to improve the combustion process by acting as pseudo-catalyst in the combustion reaction. The composition may further include surfactants such as polyethylene glycol and/or one or more polyoxyalkene derivatives of either polypropylene glycol, polyethylene glycol or sorbitol. A media of fatty acid esters is provided to dilute the combustion promoters, surfactants and other ingredients allowing accurate concentrations of these ingredients to be introduced into the fuel chamber.

Abstract: The present invention is directed to fuel additive compositions of detergents combined with fluidizers and to hydrocarbon fuel compositions containing these fuel additive compositions. The fuel additive compositions of the present invention combine a Mannich detergent, formed from reaction of an alkylphenol with an aldehyde and an amine, with a fluidizer that can be a polyetheramine or a polyether or a mixture thereof and, optionally, with a succinimide detergent. Fuel compositions containing these fuel additive compositions are very effective in reducing intake valve deposits in gasoline fueled engines, especially when the weight ratio of detergent(s) to fluidizer(s) is about 1:1 on an actives basis.

Abstract: Detergent additive compositions for gasoline-type fuels comprise at least one compound that corresponds to the general formula: in which R1, R2, R3 and R4 each represent a hydrogen atom or a hydrocarbon radical, for example alkyl, with 1 to 30 carbon atoms, whereby at least one of R1, R2, R3, and R4 is a hydrocarbon radical, n is a number from 1 to 20, m and m′ are each a number from 1 to 30, with m+m′ from 4 to 60. They can be added to gasoline-type fuels at a concentration of 20 to 5000 mg/liter.

Abstract: A splash-blendable, solubilized diesel fuel composition includes a diesel fuel, ethanol, a stabilizing additive and, optionally, an alkyl ester of a fatty acid and/or a co-solvent. The stabilizing additive is either a mixture of fatty acid alcohols, a polymeric material, or a combination of the mixture and the polymeric material.

Abstract: A fuel additive for use in the treatment of diesel fuels to reduce polluting emissions during the combustion of such fuels wherein the additive composition is formulated to contain mineral seal oil, mineral spirits, a glycol alkyl ether and at least one alkyl aromatic ethoxylated surfactant. It has been found that the fuel additive composition of the invention can be blended with such fuels to dramatically reduce emissions during the combustion of such fuels.

Abstract: Liquid energy sources, e.g., liquid fuels comprising lipid vesicles having fuel additives such as water are disclosed herein. The liquid energy sources, methods for preparation, and methods of enhancing engine performance disclosed herein employing the lipid vesicles result in enhanced fuel efficiency and/or lowered engine emissions. The invention further relates to liquid energy sources containing such additives which further comprise a polymeric dispersion assistant, which reduces the interfacial tension and coalescence of vesicles during dispersion process and storage, and thereby provide transparent looks to the liquid energy source.

Abstract: The present invention is directed to a composition containing A) at least one polyalkenene substituted amine; and B) at least one hydrocarbyl-terminated poly(oxypropylene) monool represented by the formula wherein in formula (B-I), R is an alkyl or an alkyl-substituted aromatic group of about 8 to about 20 carbon atoms; x is a number from about 13 to about 28; and wherein the weight ratio of component (A) to component (B) ranges from about 10:1 to about 1:10. The composition is useful as a fuel additive for reducing intake valve deposits or for improving the valve stick performance of an internal combustion engine. The invention also relates to concentrates and fuel compositions containing the foregoing fuel additive composition and to a method for reducing intake valve deposits or for improving the valve stick performance of an internal combustion engine.

Abstract: This invention is a fuel composition for use in internal combustion engines comprising a major amount of a base fuel which contains no more than 10% by weight of olefins and no more than 10% by weight of esters, and greater than 5% by weight based on the total composition of an oxygenate selected from the group consisting of a saturated, aliphatic monohydric alcohol having on an average from 8 to 20 carbon atoms, one or more ketones having on an average 5 to 25 carbons, and mixtures of the alcohol(s) and ketone(s). The amount of the oxygenate in the fuel composition is sufficient to provide the fuel with at least 0.5% by weight of oxygen. The oxygenate significantly reduces particulate emissions from the exhausts of diesel powered engines.

Abstract: Monoamide-containing polyether alcohol compounds of the formula: wherein R1, R2 and R3 are each independently selected from hydrogen, hydrocarbyl of 1 to 100 carbon atoms, substituted hydrocarbyl of 1 to 100 carbon atoms and polyoxyalkylene alcohol of 2 to 200 carbon atoms or R2 and R3 taken together form a heterocyclic group of 2 to 100 carbon atoms or a substituted heterocyclic group of 2 to 100 carbon atoms with the proviso that at least one of R1, R2 or R3 must be polyoxyalkylene alcohol have been found to decrease intake valve deposits, control octane requirement increases and reduce octane requirement when used as gasoline additives.

Abstract: A splash-blendable, solubilized diesel fuel composition includes a diesel fuel, ethanol, a stabilizing additive and, optionally, an alkyl ester of a fatty acid and/or a co-solvent. The stabilizing additive is either a mixture of fatty acid alcohols, a polymeric material, or a combination of the mixture and the polymeric material.

Abstract: The invention discloses a fuel oil composition comprising a major proportion of a liquid hydrocarbon middle distillate fuel oil, from 1 to 100 ppmw based on the composition of a polyoxyalkylene glycol dehazer and from 1 to 100 ppmw based on the composition of an organosilicone antifoam additive, wherein before mixing of the organosilicone antifoam with any other component of the fuel oil composition, the organosilicone antifoam additive is heated at a temperature of at least 40° C. for a sufficient period of time to achieve improved antifoam properties of the fuel oil composition; a process for the preparation of such a fuel oil composition; and a method of fuelling a road vehicle with such a composition.

Abstract: A splash-blendable, solubilized diesel fuel composition includes a diesel fuel, ethanol, a stabilizing additive and, optionally, an alkyl ester of a fatty acid and/or a co-solvent. The stabilizing additive is either a mixture of fatty acid alcohols, a polymeric material, or a combination of the mixture and the polymeric material.

Abstract: An aqueous macroemulsion to be used in place of petroleum residuum-based fuel oils such as No. 4, No. 5, and No. 6 fuel oils, as well as the vacuum residuum from the fraction distillation of petroleum, is formed by emulsifying the fuel oil with water or an aqueous liquid, the fuel oil forming the dispersed phase and the aqueous liquid forming the continuous phase. An emulsion stabilizer, and optionally various other additives, notably a lower allyl alcohol, are included to stabilize the properties of the emulsion. The emulsion is prepared by heating the fuel oil, particularly No. 6 fuel oil, and the water to a temperature above about 60° C., and combining the two heated liquids in an appropriate ratio and shearing the mixture to form the macroemulsion.

Abstract: A fuel additive for use in the treatment of liquid hydrocarbon fuels to reduce polluting emissions during the combustion of such fuels wherein the additive composition is formulated to contain mineral seal oil, mineral spirits, a glycol alkyl ether and at least one alkyl aromatic ethoxylated surfactant. It has been found that the fuel additive composition of the invention can be blended with such fuels to dramatically reduce emissions during the combustion of such fuels.

Abstract: The invention provides dispersants and dispersant viscosity index improvers which include polymers of conjugated dienes which have been hydrogenated, functionalized, optionally modified and post treated. The dispersant substances include a copolymer of two different conjugated dienes. The polymers are selectively hydrogenated to produce polymers which have highly controlled amounts of unsaturation, permitting highly selective functionalization. The polymers may be functionalized by grafting of heteroatom-containing olefins. Also provided are lubricant fluids, such as mineral and synthetic oils, which have been modified in their dispersancy and/or viscometric properties by means of the dispersant substances of the invention. Also provided are methods of modifying the dispersancy and/or viscometric properties of lubricating fluids such as mineral and synthetic lubricating oils. The dispersant substances may also include a carrier fluid to provide dispersant concentrates.

Abstract: The present invention is directed to a fuel additive composition comprising at least two components:(A) a polyether alcohol of the formula ##STR1## wherein in formula (A-1), R is hydrogen or a hydrocarbyl group of 1 to about 30 carbon atoms; R.sup.1 is hydrogen or a hydrocarbyl group of 1 to 5 carbon atoms or mixtures thereof; and x is a number from about 4 to about 40.(B) a hydrocarbylphenol having 1-3 hydrocarbyl groups such that the total weight average molecular weight of the hydrocarbyl groups is about 250 to about 6000.In one embodiment the composition further comprises (C) a nitrogen-containing dispersant.The composition is useful as a fuel additive for reducing intake valve deposits and advantageously, does not contribute to an increase in combustion chamber deposits in port fuel injected internal combustion engines. The invention also relates to concentrates and fuel compositions containing the foregoing fuel additive composition and to a method for fueling an internal combustion engine.

Abstract: Liquid energy sources, e.g., liquid fuels comprising lipid vesicles having fuel additives such as water are disclosed herein. The liquid energy sources, methods for preparation, and methods of enhancing engine performance disclosed herein employing the lipid vesicles result in enhanced fuel efficiency and/or lowered engine emissions. The invention further relates to liquid energy sources containing such additives which further comprise a polymeric dispersion assistant, which reduces the interfacial tension and coalescence of vesicles during dispersion process and storage, and thereby provide transparent looks to the liquid energy source.

Abstract: The present invention relates to crude oils and products derived therefrom comprising, as asphaltene dispersant, ethercarboxylic acids of the formulaRO(CH.sub.2 CHR.sub.1 O).sub.x (CH.sub.2 CHR.sub.2 O).sub.y CH.sub.2 --CO.sub.2 Hwhere the substituents have the meaning defined in the description.

Abstract: A splash-blendable, solubilized diesel fuel composition includes a diesel fuel, ethanol, an alkyl ester of a fatty acid, a stabilizing additive and, optionally, a co-solvent. The stabilizing additive is either a mixture of fatty acid alcohols, a polymeric material, or a combination of the mixture and the polymeric material.

Abstract: A fuel composition comprising a major amount of hydrocarbons boiling in the gasoline or diesel range and (a) about 50 to 70 parts per million by weight of a fuel-soluble aliphatic hydrocarbyl-substituted amine having at least one basic nitrogen atom wherein the hydrocarbyl group has a number average molecular weight of about 700 to 3,000; and (b) about 35 to below about 75 parts per million by weight of a hydrocarbyl-terminated poly(oxyalkylene) monool having an average molecular weight of about 500 to about 5,000, wherein the oxyalkylene group is a C.sub.2 to C.sub.5 oxyalkylene group and the hydrocarbyl group is a C.sub.1 to C.sub.30 hydrocarbyl group.

Abstract: The present invention is directed to a fuel additive composition containing (i) a polyether alcohol of the formula ##STR1## wherein R is hydrogen or a hydrocarbyl group of 1 to about 30 carbon atoms; R.sup.1 is hydrogen or a hydrocarbyl group of 1 to 5 carbon atoms or mixtures thereof provided that no more than 10 mole % of R.sup.1 is hydrogen and where the polyether alcohol is soluble in gasoline; and x is a number from about 4 to about 40; (ii) a hydrocarbylphenol having 1-3 hydrocarbyl groups such that the total weight average molecular weight of the hydrocarbyl groups is about 250 to about 6000; and (iii) optionally a third component containing a nitrogen-containing dispersant; wherein the weight ratio of the polyether alcohol to the hydrocarbylphenol is about 3:1 to about 1:20. The compositions are useful in reducing intake valve deposit and do not contribute to the increase in combustion chamber deposit in port fuel injected engines.

Abstract: A diesel fuel composition is set forth for an increased cetane number vis-a-vis conventional diesel fuel compositions. The composition generally comprises one or more compounds selected from the dialkoxy alkane (DAAK) chemical family. In a preferred embodiment of the present invention, the diesel fuel composition consists of moderate amounts of dimethoxy propane (DMPP) and dimethoxy ethane (DMET) blended into a conventional diesel fuel.

Abstract: The present invention provides a gasoline composition comprising a major amount of a gasoline suitable for use in spark-ignition engines, a minor amount of a polyalphaolefin having a viscosity at 100.degree. C. from about 2.times.10.sup.-6 m.sup.2 /s to about 2.times.10.sup.-5 m.sup.2 /s (2 to 20 centistokes), being a hydrogenated oligomer containing from 18 carbon atoms to 80 carbon atoms derived from at least one alphaolefinic monomer containing from 8 carbon atoms to 16 carbon atoms, and a minor amount of a polyoxyalkylene compound selected from glycols, mono- and diethers thereof, having number average molecular weight (M.sub.n) from about 400 to about 3000, the weight ratio of polyalphaolefin:polyoxyalkylene compound being from about 1:10 to about 10:1 and a concentrate for the preparation of such gasoline compositions.

Abstract: Additives for LPG fuels which reduce fouling, thereby increasing fuel efficiency while reducing particulates and carbon monoxide emissions, are provided. The additive compositions are produced from commonly available low cost products and comprise about 97.3 to 99.4 volume percent of a petroleum hydrocarbon which is a mixture of middle petroleum distillates and petroleum naphtha, about 0.3 to 1.5 volume percent of methanol and 0.3 to 1.2 volume percent ethoxylated alkylphenol. Optional components, such as upper cylinder lubricants, odorants and antiwear agents, may also be included in the additive composition.

Abstract: A diesel fuel additive composition comprising a mixture of a dispersant and a carrier, preferably a liquid carrier fluid. The dispersant comprises at least one member of the group consisting of polyalkylene succinimides and polyalkylene amines, the polyalkylene succinimides being the reaction product of polyalkylene succinic anhydride and a polyamine, the polyalkylene amine being the reaction product of a polyalkylene moiety and amine selected from the group consisting of monoamine and polyamine. The carrier comprises at least one oxygenate selected from the group consisting of polyalkoxylated ether, polyalkoxylated phenol, polyalkoxylated ester and polyalkoxylated amine. The additive composition reduces injector deposits in internal combustion-compression ignition engines.

Abstract: A mixture of alkoxy-terminated poly-oxymethylenes, having a varied mixture of molecular weights, is blended with diesel fuel to form an improved fuel for autoignition engines. The mixed alkoxy-terminated poly-oxymethylenes may be produced by reacting paraformaldehyde with methylal, methanol, or other alcohol for a length of time and at a temperature and pressure sufficient to form the mixed alkoxy-terminated poly-oxymethylenes. The base diesel fuel, when blended with the mixed alkoxy-terminated poly-oxymethylenes in a volume ratio of from about 2 to about 5 parts diesel fuel to 1 part mixed alkoxy-terminated poly-oxymethylenes, provides a higher quality fuel having significantly improved lubricity and reduced smoke formation, without degradation of the cetane number or smoke formation characteristics when compared with the base diesel fuel.