GB2261441A

GB2261441A - Fuel compositions

Info

Publication number: GB2261441A
Application number: GB9223539A
Authority: GB
Inventors: Dennis John Malfer
Original assignee: Afton Chemical Corp
Current assignee: Afton Chemical Corp
Priority date: 1991-11-18
Filing date: 1992-11-10
Publication date: 1993-05-19
Anticipated expiration: 2012-11-10
Also published as: GB9223539D0; GB2261441B

Abstract

A fuel composition comprises a major portion of hydrocarbons boiling in the gasoline range and an effective amount of additive comprising (i) a polyoxyalkylene compound having a molecular weight of 200 to 5000; and (ii) a reaction product of (A) polyamine and (B) at least one hydrocarbyl-substituted succinic acylating agent wherein the amount of the additive is sufficient to control engine deposits and octane requirement increase. The polyoxyalkylene compound preferably has a molecular weight in the range 1500 to 4000 and may be a polyoxypropylene glycol. An additive concentrate containing (i) and (ii) may be made up with a naphthenic or asphaltic mineral oil or a mixture of such oils.

Description

FUEL COMPOSITIONS This invention relates to hydrocarbon fuels boiling in the gasoline boiling range. More particularly it relates to gasoline additives containing certain succinimide and polyoxyalkylene compounds which additives are useful in controlling engine deposits and octane requirement increase.

The use of oxygenated polymeric compounds as fuel additives is known in the art. U.S. 2,563,101 describes a gasoline additive containing the reaction product of an alcohol and an alkylene oxide.

U.S. 2,800,400 describes a fuel additive comprising a solution of boric acid in a solvent mixture consisting of a lower alcohol and oil-soluble polyoxyalkylene compound wherein the polyoxyalkylene compound is characterized by having the following general formula: R-O-[(CHR'),-O-] -R" in which R and R" are selected from the group consisting of hydrogen, alkyl and acyl groups having from four to twenty carbon atorns, R' is hydrogen or an alkyl group having from one to five carbon atoms, n is a variable small whole number from one to four, preferably two or three, and may vary in this range even in a single long chain molecule, and y represents the number of repeating units in the chain, and may be a whole number from five to several hundred, depending on the molecular weight.

In U.S. 2,807,525, and U.S. 2,807,526 an additive comprising an oilsoluble polyoxyalkylene compound having a viscosity of from 200 to 1000 SUS at 100"F is described.

U.S. 2,853,530 relates to a fuel additive comprising a bis(2-(1methoxyisopropoxyisopropoxy)ethyl) ether and to a method for its preparation.

Block copolymers of ethylene oxide and propylene oxide are described in U.S. 4,252,540 as useful for stabilization of fuel mixtures of finely divided coal and fuel oil. U.S. 4,276,054 describes certain polyoxypropylenepolyoxyethylene copolymers which are useful for stabilizing a suspension of solid particulate carbonaceous material in a liquid hydrocarbon fuel.

U.S. 4,548,616 describes fuels containing alpha-hydro-omegahydroxypoly (oxyethylene) poly (oxypropylene) poly (oxyethylene) block polymers.

Stable gasoline-alcohol-water motor fuel compositions comprising analpha-hydro omega-hydroxy-poly(oxyethylene)poly(oxypropylene)poly(oxyethy- lene) block copolymer are described in U.S. 4,561,861.

U.S. 5,006,130 describes unleaded gasoline composition comprising a major amount of a hydrocarbon base fuel of the gasoline boiling range containing an effective amount of a mixture of (a) 2.5 ppmw or higher of basic nitrogen based on the fuel composition in the form of an oil soluble aliphatic alkylene polyamine containing at least one olefinic polymer chain attached to a nitrogen and/or carbon atom of the alkylene radicals connecting the amino nitrogen atoms of said polyamine having a molecular weight in the range from 600 to 10,000 and (b) from 75 ppmw to 125 ppmw based on the fuel composition of at least one (carrier) component which is (i) a polymer of a C, to C6 monoolefin, (ii) a copolymer of a C2 to C6 monoolefin, (iii) the corresponding hydrogenated polymer or copolymer, (iv) an oil soluble poly(oxyalkylene) alcohol, glycol or polyol or mono or di-ether thereof, (v) a naphthenic or paraffinic oil having a viscosity at 100 " C of from 2 to 15 centistokes, or (vi) a polyalphaolefin having a viscosity at 100 C. of from 2 to 20 centistokes, the weight ratio of (a) as basic nitrogen to (b) in the mixture being in the range of 0.0200 or higher.

Great Britain Patent No. 1,310,847 describes a fuel composition useful in helping to inhibit sludge and to remove sludge and other deposits which accumulate in fuel systems. The compositions comprises a major amount by weight of at least one normally liquid fuel and a minor amount by weight of an additive combination comprising (1) at least one oxy compound selected from polyglycols, and esters of glycols, polyglycols, monoether glycols and monoether polyglycols with monocarboxylic acids containing up to twenty carbon atoms, and (2) at least one fuel-soluble dispersant selected from esters, amides, amidines, imides, and amine salts of at least one substantially saturated carboxylic acid containing at least thirty aliphatic carbon atoms; wherein the weight ratio of oxy compound to dispersant is from 1:10 to 10:1.

Due to increasing demands for a cleaner environment, and the advances in internal combustion engines to meet the environmental demands, fuel compositions frequently change in order to provide the more efficient fuel mixtures for the newer engines. In light of the changes fuel compositions frequently undergo, there continues to be a need for a fuel composition having enhanced deposit reducing or controlling properties while not contributing to an increase in octane requirement over the life of the engine.

In order to provide a fuel composition with enhanced deposit controlling characteristics, this invention provides a fuel composition comprising a major portion of hydrocarbons boiling in the gasoline boiling range and a minor effective amount of additive comprising (i) a polyoxyalkylene compound having a molecular weight of greater than 1500; and (ii) a detergent/dispersant comprising the reaction product of (A) polyamine and (B) at least one hydrocarbyl-substituted succinic acylating agent, wherein the amount of the additive is sufficient to control engine deposits and octane requirement increase.

It has been found, surprisingly and unexpectedly, that the fuel compositions of this invention contribute to a reduction in deposits of fuel injectors, without negatively impacting the octane requirement or contributing to valve sticking. Accordingly, the reduction in fuel injector deposits is achieved without the need for an increase in the amount of detergent additive in the fuel composition. While not wishing to be bound by theory, it is believed that there is a synergistic effect between the detergent/dispersant and the polyoxyalkylene compound in the compositions and methods of this invention such that a greater reduction in valve deposits can be achieved by the use of the combination than can be achieved by either the detergent/dispersant or polyoxyalkylene alone.

In one of its forms, this invention provides a method for controlling engine deposits comprising providing for use as a fuel composition (a) a major amount of an unleaded gasoline and (b) a minor but effective amount of a deposit control mixture comprising (i) the reaction product of polyamine and at least one acyclic hydrocarbyl substituted succinic acylating agent, and (ii) at least one polyoxyalkylene compound having a molecular weight of greater than 1500, said minor amount being sufficient to control said engine deposits; and burning said fuel composition in an internal combustion engine.

In yet another embodiment, this invention provides fuel additive concentrate comprising a) the reaction product of (i) polyamine and (ii) at least one acyclic hydrocarbyl substituted succinic acylating agent; b) a naphthenic or asphaltic mineral oil or a mixture of such oils; and c) an amount of a polyoxyalkylene compound, said amount sufficient to control fuel injector deposits.

These and other embodiments of this invention will be apparent from the ensuing description and appended claims.

Detergent/dispersant. As noted above, the fuel additive of this invention comprises, as a detergent/dispersant, the reaction product of (i) polyamine and (ii) at least one acyclic hydrocarbyl substituted succinic acylating agent. The polyamine reactant may be one or more alkylene polyamine(s), which polyamines are may be linear, branched, or cyclic; or a mixture linear, branched and/or cyclic polyamines and wherein each alkylene group contains from 1 to 10 carbon atoms.

A preferred polyamine is a polyamine containing from 2 to 10 nitrogen atoms per molecule or a mixture of polyamines containing an average of from 2 to 10 nitrogen atoms per molecule. A particularly preferred polyamine is a polyamine or mixture of polyamines having from 3 to 7 nitrogen atoms, with triethylene tetramine or a combination of ethylene polyamines which approximate triethylene tetramine being the most preferred. In selecting an appropriate polyamine, consideration should be given to the compatibility of the resulting detergent/dispersant with the gasoline fuel mixture with which it is mixed.

Ordinarily the most highly preferred polyamine, triethylene tetramine, will comprise a commercially available mixture having the general overall composition approximating that of triethylene tetramine but which can contain minor amounts of branched-chain and cyclic species as well as some linear polyethylene polyamines such as di ethylene triamine and tetraethylene pentamine. For best results, such mixtures should contain at least 50% and preferably at least 70% by weight of the linear polyethylene polyamines enriched in triethylene tetramine.

The acylating agent which is reacted with the polyamine is an acyclic hydrocarbyl substituted succinic acylating agent in which the substituent contains an average of 50 to 100 (preferably 64 to 80) carbon atoms. In order to accomplish the objectives of this invention, it is important that the acyclic hydrocarbyl substituted succinic acylating agent have an acid number in the range of 0.7 to 1.1 (preferably in the range of 0.8 to 1.0, and most preferably about 0.9).

To achieve the objectives of this invention, the molar ratio of acylating agent to polyamine in the reaction product of (i) and (ii) is desirably greater than 1:1. Preferably the molar ratio of acylating agent to polyamine in the reaction product is in the range of 1.5 1 to 2.2: 1, more preferably from 1.7 : 1 to 1.9 1, and most preferably about 1.8 1.

The acid number of the acyclic hydrocarbyl substituted succinic acylating agent is determined in the customary way -- i.e., by titration -- and is reported in terms of mg of KOH per gram of product. It is to be noted that this determination is made on the overall acylating agent with any unreacted olefin polymer (e.g., polyisobutene) present.

The acyclic hydrocarbyl substituent of the acylating agent is preferably an alkyl or alkenyl group having the requisite number of carbon atoms as specified above. Alkenyl substituents derived from poly-a-olefin homopolymers or copolymers of appropriate molecular weight (e.g., propene homopolymers, butene homopolymers, and C3 and C4 a-olefin copolymers) are suitable. Most preferably, the substituent is a polyisobutenyl group formed from polyisobutene having a number average molecular weight (as determined by gel permeation chromatography) in the range of 700 to 1200, preferably 900 to 1100, most preferably 940 to 1000.

Acyclic hydrocarbyl-substituted succinic acid acylating agents and methods for their preparation and use in the formation of succinimide are well known to those skilled in the art and are extensively reported in the patent literature. See for example the following U. S. Patents.

3,018,247 3,231,587 3,399,141 3,018,250 3,272,746 3,401,118 3,018,291 3,287,271 3,513,093 3,172,892 3,311,558 3,576,743 3,184,474 3,331,776 3,578,422 3,185,704 3,341,542 3,658,494 3,194,812 3,346,354 3,658,495 3,194,814 3,347,645 3,912,764 3,202,678 3,361,673 4,110,349 3,215,707 3,373,111 4,234,435 3,219,666 3,381,022 When utilizing the general procedures such as described in these patents, the important considerations insofar as the present invention is concerned, are to insure that the hydrocarbyl substituent of the acylating agent contain the requisite number of carbon atoms, that the acylating agent have the requisite acid number, that the acylating agent be reacted with the requisite polyethylene polyamine, and that the reactants be employed in proportions such that the resultant succinimide contains the requisite proportions of the chemically combined reactants, all as specified herein. When utilizing this combination of features, detergent/dispersants are formed which possess exceptional effectiveness in controlling or reducing the amount of induction system deposits formed during engine operation and which permit adequate demulsification performance.

As pointed out in the above listed patents, the cyclic hydrocarbyl-substituted succinic acylating agents include the hydrocarbyl-substituted succinic acids, the hydrocarbyl-substituted succinic anhydrides, the hydrocarbyl-substituted succinic acid halides (especially the acid fluorides and acid chlorides), and the esters of the hydrocarbyl-substituted succinic acids and lower alcohols (e.g., those containing up to 7 carbon atoms), that is, hydrocarbyl-substituted compounds which can function as carboxylic acylating agents. Of these compounds, the hydrocarbyl-substituted succinic acids and the hydrocarbyl-substituted succinic anhydrides and mixtures of such acids and anhydrides are generally preferred, the hydrocarbyl-substituted succinic anhydrides being particularly preferred.

The acylating agent used in producing the detergent/dispersants of this invention is preferably made by reacting a polyolefin of appropriate molecular weight (with or without chlorine) with maleic anhydride. However, similar carboxylic reactants can be employed such as maleic acid, fumaric acid, malic acid, tartaric acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, mesaconic acid, ethylmaleic anhydride, dimethylmaleic anhydride, ethylmaleic acid, dimethylmaleic acid, and hexylmaleic acid, including the corresponding acid halides and lower aliphatic esters.

The reaction between components (i) and (ii) is generally conducted at temperatures of 800 C to 200 C, more preferably 140 " C to 180 " C, such that a succinimide is formed. These reactions may be conducted in the presence or absence of an ancillary diluent or liquid reaction medium, such as a mineral lubricating oil solvent. Suitable solvent oils include natural and synthetic base oils having a volatility of 50 percent or less as determined by the test method described herein. Suitable synthetic diluents include polyesters, hydrogenated or unhydrogenated poly-a-olefins (PAO) such as hydrogenated or unhydrogenated 1-decene oligomer. Blends of mineral oil and synthetic oils are also suitable for this purpose.In a particularly preferred embodiment, the reactions are conducted in the substantial absence of an ancillary diluent oil so that the reaction product is essentially free of paraffinic mineral oils. By essentially free is meant that the reaction product contains less than about 1% by weight paraffinic mineral oil.

As used herein, the term succinimide is meant to encompass the completed reaction product from components (i) and (ii) and is intended to encompass compounds wherein the product may have amide, amidine, and/or salt linkages in addition to the imide linkage of the type that results from the reaction of a primary amino group and an anhydride moiety.

Polvoxvalkvlene Compounds. A key feature of this invention is the use of certain polyoxyalkylene compounds as a component in fuel additive compositions. The polyoxyalkylene compounds which may be used can be represented by the following formula RI~(R2~0)n~R3 wherein R1 is hydrogen, hydroxy, alkyl, cycloalkyl, aryl, alkylaryl, aralkyl, alkoxy, cycloalkoxy, amine, or amino group having 1-200 carbon atoms, R2 is an alkylene group having 2-10 carbon atoms, R3 is hydrogen, hydroxy, alkyl, cycloalkyl, aryl, alkylaryl, aralkyl, alkoxy, cycloalkoxy, amine group having 1-200 carbon atoms, and n is an integer from 1 to 500 representing the number of repeating alkoxy groups.Preferred polyoxyalkylene compounds are comprised of repeating units formed by reacting an alcohol with an alkylene oxide wherein the alcohol and alkylene oxide contain the same number of carbon atoms. It is most preferred that the repeating units be comprised substantially of C3H6-O and that Rl be a hydroxy group and R3 be hydrogen. Polyoxyalkylene compounds useful in fuel compositions of this invention which are commercially available include Polyglycol P-1200, Polyglycol L1150, or Polyglycol P-400, which are commercially available from the Dow Chemical Company. The average molecular weight of the polyoxyalkylene compounds of this invention is preferably in the range of from 200 to 5000, more preferably from 1000 to 4500, and most preferably from above 1500 to 4000.For purposes of this invention, the end groups, R1 and R3, are not critical as long as end groups are selected such that the polyoxyalkylene compound is sufficiently soluble in the fuel and additive compositions.

The polyoxyalkylene compounds of this invention may be prepared by condensation of the corresponding oxides, or oxide mixtures, such as ethylene or 1,2-propylene oxides as set forth more fully in U.S. Patents Nos. 2,425,755; 2,425,845; 2,448,664; and 2,457,139.

It is particularly preferred that the fuel compositions of this invention include other conventional additives such as antioxidants, demulsifiers, corrosion inhibitors, aromatic solvents, diluent oils. It is particularly preferred that the fuel compositions of this invention contain an amount of diluent oil sufficient to control valve deposits in internal combustion engines.

Diluent Oil. The diluent oil useful in fuel compositions of this invention is suitably a mineral oil having a viscosity index of less than about 90 and a volatility of 50 percent or less. It has been found surprisingly, and quite unexpectedly, that when particular succinimide, polyoxyalkylene compound, are admixed, with particular mineral oils and gasoline in particular proportions, the octane requirement increase of internal combustion engines is effectively controlled. By "effectively controlled" is meant, that the formation of deposits which tend to increase the octane requirement are significantly inhibited, and/or engines initially containing heavy deposits, exhibit a substantial reduction in deposits when operated in accordance with the method of this invention.

Mineral oils having suitable volatilities include naphthenic and asphaltic oils which are defined generally as those found along the Gulf Coast such as a Coastal Pale (commercially available from Exxon Co.). A typical Coastal Pale may contain 3-5 wt. to polar material, 20-35 wt.% aromatic hydrocarbons, and 50-75 wt.% saturated hydrocarbons and having a molecular weight in the range of from 300 to 600. Asphaltic oils are defined as containing high molecular weight (ca > 800) compounds with high polar functionality and little or no pure hydrocarbon type compounds. Principal polar functionalities generally present in such asphaltic oils include carboxylic acids, phenols, amides, carbazoles, and pyridine benzologs. Typically, asphaltenes contain 40-50% by weight aromatic carbon and have molecular weights of several thousand.

Asphaltic oils are generally found along the West Coast. Preferably the mineral oil has a viscosity at 100 " F of less than about 1600 SUS more preferably less than about 1500 SUS, and most preferably between 800 and 1500 SUS at 100"F. It is highly desirable that the mineral oil have a viscosity index of less than about 90, more particularly, less than about 70 and most preferably in the range of from 30 to 60. Suitable mineral oils may be selected from solvent extracted, hydrotreated, and non-hydrotreated mineral oils, however, the hydrotreated mineral oils are particularly desirable for use in the additive compositions of this invention.

The weight ratio of succinimide, polyoxyalkylene, and diluent oil in the mixtures of this invention is another particularly key feature of this invention.

It has been discovered that a weight ratio of less than about 1 part of 25 to 55 wt.% succinimide and 45 to 75 wt.% polyoxyalkylene to 3 parts diluent oil achieves the purposes of this invention. Preferably the weight ratio of succinimide and polyoxyalkylene to diluent oil is in the range of from 1 : 1.5 to 1 : 2.8 and most preferably, the weight ratio is from 1 : 1.2 to 1 : 2.5.

Antioxidant. Various compounds known for use as oxidation inhibitors can be utilized in the practice of this invention. These include phenolic antioxidants, amino antioxidants, sulfurized phenolic compounds, and organic phosphites, among others. For best results, the antioxidant should be composed predominantly or entirely of either (1) a hindered phenol antioxidant such as 2tert-butylphenol,2,6-di-tert-butylphenol,2,4,6-tri-tert-butylphenol,4-methyl-2,6-di-tert-butylphenol, 4,4'-methylenebis-(2,6-di-tert-butylphenol), and mixed methylene bridged polyalkyl phenols, or (2) an aromatic amine antioxidant such as the cycloalkyl-di-lower alkyl amines, and phenylenediamines, or a combination of one or more such phenolic antioxidants with one or more such amine antioxidants.

Particularly preferred for use in the practice of this invention are combinations of tertiary butyl phenols, such as 2,6-di-tert-butylphenol, 2,4,6-tri-tert-butyl-phenol, and o-tert-butylphenol.

Demulsifier. A wide variety of demulsifiers are available for use in the practice of this invention, including, for example, polyoxyalkylene glycols, oxyalkylated phenolic resins, and like materials. Particularly preferred are mixtures of alkylphenol or polyoxyalkylene glycols, and oxyalkylated alkylphenolic resins, such as are available commercially from Petrolite Corporation under the TOLAD trademark. One such proprietary product, identified as TOLAD 9308, is understood to be a mixture of these components dissolved in a solvent composed of heavy aromatic naphtha and isopropanol. This product has been found efficacious for use in the compositions of this invention. However, other known demulsifiers can be used such as TOLAD 286.

Corrosion Inhibitor. Here again, a variety of materials are available for use as corrosion inhibitors in the practice of this invention. Thus, use can be made of dimer and trimer acids, such as are produced from tall oil fatty acids, oleic acid, linoleic acid, or the like. Products of this type are currently available from various commercial sources, such as, for example, the dimer and trimer acids sold under the HYSTRENE trademark by the Humko Chemical Division of Witco Chemical Corporation and under the EMPOL trademark by Emery Chemicals.Another useful type of corrosion inhibitor for use in the practice of this invention are the alkenyl succinic acid and alkenyl succinic anhydride corrosion inhibitors such as, for example, tetrapropenylsuccinic acid, tetrapropenylsuccinic anhydride, tetradecenylsuccinic acid, tetradecenylsuccinic anhydride, hexadecenylsuccinic acid, and hexadecenylsuccinic anhydride. Also useful are the half esters of alkenyl succinic acids having 8 to 24 carbon atoms in the alkenyl group with alcohols such as the polyglycols.Preferred materials are the aminosuccinic acids or derivatives thereof represented by the formula:

wherein each of R2, R3, R5 and R6 is, independently, a hydrogen atom or a hydrocarbyl group containing 1 to 30 carbon atoms, and wherein each of Rl and R4 is, independently, a hydrogen atom, a hydrocarbyl group containing 1 to 30 carbon atoms, or an acyl group containing from 1 to 30 carbon atoms.

The groups R1, R2, R3, R4, R5, and R6 when in the form of hydrocarbyl groups, can be, for example, alkyl, cycloalkyl or aromatic containing groups.

Preferably Rl, R2, R3, R4 and R5 are hydrogen or the same or different straightchain or branched-chain hydrocarbon radicals containing 1-20 carbon atoms.

Most preferably, R1, R2, R3, R4, and Rs are hydrogen atoms. R6 when in the form of a hydrocarbyl group is preferably a straight-chain or branched-chain saturated hydrocarbon radical.

Most preferred is a tetralkenyl succinic acid of the above formula wherein R1, R2, R3, R4 and Rs are hydrogen and R6 is a tetrapropenyl group.

Aromatic Hvdrocarbon Solvent A wide variety of aromatic hydrocarbon solvents can be used with this invention such as benzene, and alkyl substituted benzene or mixtures thereof. Particularly useful are mixtures of o-, p-, and m- xylenes and mesitylene and higher boiling aromatics such as Aromatic 150 which is available from Chemtech. However, other mixtures of aromatic hydrocarbon solvents may also be used.

The relative proportions of the various ingredients used in the additive concentrates and fuel compositions of this invention can be varied within reasonable limits. However, for best results, these compositions should contain from 25 to 55 parts by weight (preferably from 30 to 40 parts by weight) of succinimide, from 45 to 75 parts by weight (preferably from 60 to 70 parts by weight) of polyoxyalkylene, up to 75 parts by weight (preferably from 50 to 65 parts by weight) of diluent oil, 0 to 5 parts by weight (preferably, from 1 to 3 parts by weight) of antioxidant, from 0 to 10 parts by weight (preferably, from 0.3 to 3 parts by weight) of demulsifier, from 0 to 75 parts by weight (preferably 5 to 25 parts by weight) of aromatic hydrocarbon solvent, and from 0 to 5 parts by weight (preferably, from 0.025 to 1.0 part by weight) of corrosion inhibitor per each one hundred parts by weight of fuel additive composition.

The above additive compositions of this invention are preferably employed in hydrocarbon mixtures in the gasoline boiling range or hydrocarbon/oxygenate mixtures, or oxygenates, but are also suitable for use in middle distillate fuels, notably, diesel fuels and fuels for gas turbine engines. The nature of such fuels is so well known to those skilled in the art as to require no further comment. By oxygenates is meant alkanols and ethers such as methanol, ethanol, propanol, methyl-tert-butyl ether, ethyl-tert-butyl ether, and tert-amylmethyl ether. It will of course be understood that the base fuels may contain other commonly used ingredients such as cold starting aids, dyes, metal deactivators, octane improvers, cetane improvers, emission control additives, and antioxidants.

When formulating the fuel compositions of this invention, the additives are employed in amounts sufficient to reduce or inhibit engine deposits and octane requirement increase in an internal combustion engine. Generally speaking, the fuel additive comprising a succinimide, a polyoxyalkylene compound, a mineral oil having a viscosity index of less than about 90 and a volatility of 50 percent or less will be employed in unleaded gasoline in minor amounts such that the gasoline portion of the fuel is the major component. By minor amount is meant less than 3000 parts per million parts of gasoline, preferably, less than 1500 parts per million parts of gasoline. A particularly preferred amount of additive is in the range of from 600 to 1200 parts per million parts of gasoline.The other components which are preferably used in conjunction with the detergent/dispersant and diluent oil can be blended into the fuel individually or in various sub-combinations. However, it is definitely preferable to blend all of the components concurrently using an additive concentrate of this invention as this takes advantage of the mutual compatibility afforded by the combination of ingredients when in the form of an additive concentrate.

The following Examples in which all parts are by weight illustrate, but are not intended to limit, this invention.

Example 1 A fuel additive concentrate is prepared from the following ingredients: (a) 60 parts of a detergent/dispersant formed by reacting polyisobutenylsuccinic anhydride having an acid number of 1.1 (made by reaction of maleic anhydride and polyisobutene having a number average molecular weight of 950) with a commercial mixture approximating triethylene tetramine, in a mole ratio of 2:1 respectively.

(b) 140 parts of polyoxyalkylene compound having an average molecular weight in the range of from 1500 to 2000.

(c) 2 parts of a tertiary butylated phenol antioxidant mixture containing a minimum of 75 percent of 2,6-di-tert-butyl phenol, 10-15 percent of 2,4,6-tri-tert-butylphenol, and 15-10 percent of 2-tert-butyiphenol.

(d) 3.4 parts of a demulsifier mixture composed of polyoxyalky lene glycols and oxyalkylated alkylphenolic resins in alkyl benzenes (TOLAD 9308).

(e) 48 parts of Aromatic 150 solvent.

This concentrate is blended with gasolines and with diesel fuels at concentrations of 250 pounds per thousand barrels (PTB).

Example 2 A fuel additive composition of this invention was used in an 2.3 L Ford engine in a standard ALI test to determine fuel injector deposits and octane requirement increase. The additive composition of Example 1 was added to Union Oil Co. base fuel at a rate of 250 PTB. As a result of the test, the injector deposits in milligrams are as follows: Injector Deposits (mg) 1 27.4 2 63.5 3 29.6 4 40.3 AVG. 40.2 The net ORI increase for the test was 7.0.

Example 3 Utilizing fuel compositions containing (a) and (b) of Example 1, valve deposits were determined utilizing a Briggs & Stratton 3 Hp engine with SAE 10W-40 oil. The length of the test was 150 hours. After breaking the engine in at varying speeds and loads the engine was then run at 3,000 RPM with a load of 500 Watts/0.67 Hp. The spark plug temperature was maintained at about 400 F. Oil level was checked often and the oil was changed after 80 hours.

Valves were weighed before and after the test to determine the amount of deposits. Using Phillips J-37 unleaded, untreated fuel, the amount of intake valve deposits was 300-328 mg. With the treated fuel under the same test conditions, the amount of intake valve deposits are given in Table 1 for J-35 fuel and Table 2 for J-37 fuel with the treat rates of detergent/ dispersant and polyol indicated.

(Note, negative numbers for amount of deposits indicate that the valves weighed less than when the test was initiated for that particular run).

Table 1l Run No. Polyol Detergent Deposits (ptb) (ptb) (mg) 1 75 40 0.40 2 75 50 -0.31 3 87 45 -0.80 4 100 40 -4.30 5 100 50 -6.40 6 120 60 -6.40 1 J-35 fuel from Phillips Petroleum Co.

Table 22 Run No. Polyol Detergent Deposits (ptb) (ptb) (mg) 1 50 25 9.8 2 60 30 -0.18 3 60 30 0.00 4 60 30 0.7 5 60 30 2.7 6 60 35 1.60 7 60 40 -1.80 8 70 35 1.10 9 70 35 1.1 10 75 40 0.4 11 75 50 -0.31 12 80 30 -6.10 13 80 30 -0.30 14 80 30 8.3 15 80 35 -3.50 16 80 35 -8.8 17 80 40 -0.70 18 85 45 -0.8 19 100 30 68.70 20 100 30 34.0 21 100 40 4.3 22 100 40 -6.2 23 100 40 4.1 24 100 50 -6.4 25 120 60 -6.4 2 a-37 fuel from Phillips Petroleum Co.

VOLATILITY DETERMINATION METHOD To determine the volatility of the mineral oils suitable for use with this invention, the following procedure is used. Mineral oil (110-135 grams) is placed in a three-neck, 250 mL round-bottomed flask having a threaded port for a thermometer. Such a flask is available from Ace Glass (Catalog No. 6954-72 with 20/40 fittings). Through the center nozzle of the flask is inserted a stirrer rod having a Teflon blade, 19 mm wide x 60 mm long (Ace Glass Catalog No.

8085-07). The mineral oil or poly-a-olefin is heated in an oil bath to 300 O C for 1 hour while stirring the oil in the flask at a rate of 150 rpm. During the heating and stirring, the free space above the oil in the flask is swept with 7.5 L/hr of air or nitrogen. The volatility of the oil thus determined is expressed in terms of the percentage of oil remaining based on the total initial charge of oil.

Claims

1. A fuel composition comprising a major portion of hydrocarbons boiling in the gasoline boiling range and an effective amount of additive comprising (i) a polyoxyalkylene compound having a molecular weight of greater than about 1500; and (ii) a reaction product of (A) polyamine and (B) at least on hydrocarbyl-substituted succinic acylating agent, wherein the amount of said additive is sufficient to control engine deposits and octane requirement increase.

2. The composition of Claim 1 wherein the polyoxyalkylene compound is a polyoxypropylene glycol having a number average molecular weight of from above 1500 to 4000.

3. The composition of Claim 2 further comprising a) an unhydrotreated poly a-oiefin.

b) an antioxidant; c) a demulsifier; d) a corrosion inhibitor; e) an aromatic hydrocarbon solvent; or f) any combination of any two, three, four, or all five of components (a), (b), (c), (d) and (e).

4. A method for controlling engine deposits comprising providing for use as a fuel composition (a) a major amount of an unleaded gasoline and (b) a minor but effective amount of a deposit control mixture comprising (i) the reaction product of polyamine and at least one acyclic hydrocarbyl substituted succinic acylating agent, and (ii) at least one polyoxyalkylene compound having a molecular weight of greater than about 1500, said minor amount being sufficient to control said engine deposits; and burning said fuel composition in an internal combustion engine.

5. The method of Claim 4 wherein the polyoxyalkylene compound is a polyoxypropylene glycol having a number average molecular weight of from above 1500 to 4000.

6. The method of Claim 5 further comprising a) an unhydrotreated poly a-olefin.

7. A fuel additive concentrate comprising: a) the reaction product of (i) polyamine and (ii) at least one acyclic hydrocarbyl substituted succinic acylating agent; b) a naphthenic or asphaltic mineral oil or a mixture of such oils; and c) an amount of a polyoxyalkylene compound, said amount sufficient to control fuel injector deposits.

8. The composition of Claim 7 wherein the polyoxyalkylene compound is a polyoxypropylene glycol having a number average molecular weight of 1200 to 2000.

9. The composition of Claim 8 further comprising a) an unhydrotreated poly a-olefin; b) an antioxidant; c) a demulsifier; d) a corrosion inhibitor; e) an aromatic hydrocarbon solvent; or f) any combination of any two, three, four, or all five of components (a), (b), (c), (d) and (e).

10. A fuel additive concentrate as claimed in claim 7 substantially as described in Example 1.

11. A method as claimed in claim 4 substantially as described in Examples 2 or 3.