CA1299871C - Fuel composition - Google Patents

Abstract

ABSTRACT

A fuel composition is disclosed for an internal combustion engine, for reducing and/or preventing injector fouling in a multiport fuel injection means. The engine composition comprises:
A. gasoline; and an effective amount of B. an antifouling agent having the formula wherein: R1 is C6 to C24 alkyl, aryl, cycloaliphatic, heterocyclic, substituted alkyl or substituted aryl; R2 and R3 independently are C1 to C24 alkyl, aryl, substituted alkyl or aryl, cycloaliphatic or heterocyclic; and C. a demulsifier selected from the group consisting of:
i. a fatty acid alkylamine reaction product;
ii. a solution of oxyalkylated alkylphenol formaldehyde resins and polyglycols; and mixtures of i and ii. Additives for gasoline are also disclosed.

Description

12~9871 3ACRGROUND OF THE r NVENTION

This invention i~ diracted to an anti-fouling fuel composition. More specifically, the present invention is directed at a fuel compo~ition hav$ng particular applicability in minimizing and/or prsventing injector fouling in gasoline engines equipp~d with electronically controlled multiport fuel injector~.

Over the past several year~, improvements have been mad~ in the performance of internal combu~-tion engine~. one of the mo~t significant improvements which ha~ b~en made has been the wide~pread us- o~ fuel in~ection to improve the perfor~ance and fuel economy of int-rnal combustion engin-~. Whila carburetor-equipped internal combustion engines admix the air and fu-l for di~tribution through a m~n~fold to all of the cylinder~, in a fu-l injected engina the fuel i3 in-~ect~d into the manifold clos~ to the intak- valve of each cylind-r for combustion. Fuel injection ~y~tems ar- of two ba~ic type , mechanically controlled and electronically controlled. ~he early fuel injected engine~ wer- controlled mechanically, i.e., the opera-tion of each injector wa~ controlled by pres~ure.
Recently, however, the u9e of electronically con-trolled fuel injection engine~ has bacome increasingly widespread. In an electronically controlled fuel injection system sensors disposed in the exhau~t are employed to maintain the air to fuel ratio within narrow limit~. Electronically controlled fuel in-jection ~y-~temY offer the same performance and fuel economy benefits that would be achieved with mechani-~k 1~987~

cally controlled fuel injection systems and also serveto more closely regulate fuel-air mixtures to thereby enable the catalytic converter to oxidize carbon monoxide and hydrocarbons to carbon dioxide and simultaneously to reduce nitrogen oxide and thus meet emi33ions control legislation. Such legislation imposing as it did strict control of exhaust pollutants utimately led to the development and widespread appli-cation of new technologies such as electronic fuel injection.

It has been found that the electronically controlled fuel injector systems have small port opening3 which are prone to fouling by deposits. These deposits are believed to occur, at least in part, by gasoline and oil vapor, which i~ present in close proximity to the injector tip, becoming baked onto the hot surfaces of the injector pintle and OQ the ~urfaces of the annulus suErounding the pintle when the engine is qhut off. ThesQ deposits restrict the fuel flow to that particular cylinder. Thi~, in turn, causes a sensor disposed in the exhaust to detect a higher than desired oxygen to fuel ratio. The sensor will attempt to correct this condition by increasing the amount of fuel injected into all of the cylinders~ This, in turn, will re~ult in a richer than desired fuel to air ratio in the exhaust. The sensor then will attempt to correct this by decreasing the amount of fuel injected into each cylinder. This cyclical adjustment of the fuel to air ratio ranging between too lean a mixture and too rich a mixture can at times result in poor operating performance of the vehicle. In addition, close tole~ances in this new type of injector and con-currently higher underhood temperature also tend to enhance deposit formation resulting in poor vehicle i2~98'71 driveability and exhaust pollut-ant emission levels which exceed the maximum levels set by emisisons control legislation.

It has been found that conventional gasoline detergents, which have proven effective in preventing and/or eliminating carburetor deposits are not par-ticularly effective in removing and/or preventing deposit build-up that may occur in electronically con-trolled fuel injection system~. Pre~ently available methods for removing deposits from fuel injector orifices typically comprise either mechanically cleaning the injectors or the addition to the fuel of relatively large quantitie~ of particular additives.
Mechanical cleaning, which may involve either the com-plete removal of the injector for manual deposit re-moval or the use of polar solvents for flu~hing the depo-~it-Q free, i3 not desired becaus~ of the rela~
tively high cost and inconvenience. Currently avail-able additive~ are not particularly de~irable becau-~e product recommendation indicate they muqt be used at relatively high concentrations, i.e. about one to about two tons par thousand barrel of fuel.

To be u~eful commercially a gasoline additive for reducing and/or preventing injector port foul~ng mu~t be effective at low concentration, mu~t not significantly affect the combu~tion characteri-~tic~
of the fuel and must not foul the catalytic converter catalyst.

The additive also should not promote exce~sive emulsi~ication, and should not promote the formation of two organic phases.

~Z~987~

Additives have been added to gasoline to improve certain properties of the fuel. U.S. Patent ~Jo. 3,387,953 is directed at the use of organo-substituted nitrogen oxides, particularly amine oxides for rust inhibition and ac anti-icing agents in gasoline. Several representative formulas for amine oxides are given including the following:

I

R~ N - > O

where Rl is C6-C24 alkyl, aryl, cycloaliphatic, heterocyclic, subqtituted alkyl or substituted aryl;
and R2 and R3 are the same or different and are Cl-C2~
alkyl, aryl, sub~tituted alkyl or aryl, cycloaliphatic or heterocylic. R2 and R3 preferably comprise hydroxy substituted alkyls. These compound3 typically are added to gaYoline in a concentration within the range of about 2.0 to about 100 pound~ of amine oxide per 1,000 barrels of gasoline (ptb). Among the most preferred additives is bis(2-hydroxy e~hyl) cocoamine oxide.

U.S. Patent No. 3,594,139 i~ directed at a rust-inhibitor concentrate that can be blended with ga~oline year-round including amine oxide~ having the aforementioned formula, with a particularly preferred amine oxide compri~ing bis(2-hydroxy ethyl) cocoamine oxide. The concentrate also comprises a liquid aromatic C7-Clo hydrocarbon and an aliphatic monohydric or dihydric alcohol having from about 6 to about 13 carbon atoms. Preferred aromatic hydrocarbons comprise ortho, meta and mixed xylenes. Preferred aliphatic 129987~

alcohols comprise C6-C13 oxo alcohols. ~he examples disclose the combination of xylene, bis(2 hydroxyethyl) cocoamine oxide, and C8 oxo alcohols.

The amine oxides described above have been typically used to inhibit rust and carburetor icing.
While these compound were used commercially during the late 1960's and early 1970' , their use in the United States was discontinued as more effective additives were found. The use of these compounds had been dis-continued in the United States well before the develop-ment of electronically controlled, fuel injected engines.

It has been discovered that use of amine oxides at concentration~ generally higher than that which previously had been used for rust inhibition would be effective in preventing and/or reducing injector fouling in multiport fuel injected engines.
However, when amine oxides are used at these higher concentration~ they tend to act as emulsifiers which bring into the gasoline layer~ water, sediment and impuritie~ which may have entered the product distribu-tion system. This prevents nor~al separation of the gasoline from any water or normally in~oluble impurities. The admixture of these impurities i9 not desired with the gasoline, since this would result ir excessive fuel filter fouling and in poor vehicle operation. In addition, it i~ believed that formatior of an emulsion results in undesirable concentration of the amine oxide additive at the interface. It also hac been found that the use oE certain solvents to produc~
an additive concentrate having low cloud and pour points may form two organic laye~S resulting in unever additive distribution.

Accordingly, it would be desirable to provide an additive package ~or gasoline which will be effective in reducing and/or eliminating fouling without forming an emulsion with water bottoms and interfacial solids.

It also would be desirable to pro~ide an additive package having a demul~ifying agent which is effective in the presence of both neutral and basic waters.

It also would be desirable to provide an additive concentrate which has low cloud and pour points and which does not result in the formation of more than one organic layer.

Accordingly, it would be desirable to pro-ri~e a gasoline additive package which is relatively inexpen3ive and effective at low concentrations to reduce and/or eliminate injec~or fouling.

It also would be de~irable to provide a gasoline additive package which is non-corrosive, non-deleteriou~ to the catalytt, and does not effect the combustion characteristics of the fuel.

It also would be de~irable to provide a gasoline additive package which could be ea~ily added to the finished gasoline at any point during the storage and/or distribution system.

1~987~

SUMMARY OF THE INVE~I~ION

The present invention is directed at a fuel composition for minimizing and/or preventing injector fouling in a multiport electronically controlled fuel injected engine. The compo~ition comprises:

A. gasoline B. an anti-fouling agent having the formula:

I

Rl -- N --> O
I

where: Rl is C6-C24 alkyl, aryl, cycloaliphatic, heterocyclic, subqtituted alkyl or substituted aryl;
and R2 and R3 independently are Cl-C24 alkyl, aryl, substituted alkyl or aryl, cycloaliphatic or heterocylic; and, C. a demulsifier comprising one or more of the following demulsifying agents:

i. a eatty acid alkylamine reaction product; and, ii. a solution of oxyalkylated alkyl phenol formaldehyde resins and polyglycols.

In this composition Rl preferably is C6-C20 alkyl, or alkylated aYyl, and R2 and R3 independently are Cl-C12 hydroxy substituted alkyl. In a more i2~9871 preferred composition Rl, comprises C8-Clg substituents derived from fatty acid. The additive preferably is selected from the group consisting of bis(2-hydroxy ethyl) cocoamine oxide, bis(2-hydroxy ethyl) tallow amine oxide, bis(2-hydroxy ethyl) stearyl-amine oxide, dimethylcocoamine oxide, dimethyl hydrogenated tallow amine oxide, dimethylhexadecylamine oxide and mixtures thereof. A particularly preferred additive is bis(2-hydroxy ethyl) cocoamine oxide. The anti-fouling agent concentration in the fuel typically may range between about 0.5 and about 50 ptb (i.e. about 2 to about 200 ppm, by weight), preferably between about 5 and about 15 ptb (i.e. about 20 to about 60 ppm).

In demulsifying agent (ii) the oxyalkylated compounds preferably comprise ethylene oxide and propylene oxide copolymers. The active concentration of the demulsifyinq agent may range between about 0.025 and about 1~ ptb (about 0.1 and about 40 ppm), preferably between ahout 0.25 and about 2.0 otb (about 1.0 and 8.0 ppm).

~ fuel composition may comprise:

A. about 2 to about 200 ppm bis(2-hydroxy ethyl) cocoamine oxide; and, 8. about 0.1 to about 40 ppm of a demulsifying agent selected from the group consistina of:

i. fatty acid alkylamine reaction product;

ii. a solution of oxyalkylated alkylphenol formaldehyde resins and polyglycols; and mixtures of i and ii.

12C~'9871 A preferred composition comprises:

A. about 20 to about 60 ppm bis(2-hydroxy ethyl) cocoamine oxide; and, B. about 1 to about 8 ppm of a demulsifying agent selected from the aroup consisting of:

i. fatty acid alkylamine reaction product;

ii. a solution of oxyalkylated alkylphenol formaldehyde resins and polyglycols; and mixtures of i and ii.

A preferred fuel composition includes an additive Package comprising:

~ . about 20 ppm to about 60 ppm bis(2-hydroxy ethyl) cocoamine oxide;

B. about 0.5 ppm to about 4 ppm fatty acid alkylamine reaction product; and, C. about 0.5 Ppm to about 4 ppm of a solu-tion of oxyalkylated alkylphenol formaldehyde resins and polyglycols.

The present invention also is directed at a fuel additive concentrate for internal combustion engines, said additive concentrate comprising:

A. about 5 to about 50 wt.~ bis(2-hydroxy ethyl) cocoamine oxide;

~2~871 B. about 0.25 to about 10 wt.~ of a demulsifying agent selected from the group consisting of:

i. fatty acid alkylamine reaction product;

ii. a solution of oxyalkylated alkylphenol formaldehyde resins and polyglycols; and mixtures of i and ii; and, C. about 40 to about 95 wt.% solvent.

The qolvent preferably comprises xylene and a C4+ alcohol, preferably a C4-C12 alcohol, more preferably a C8 alcohol and most preferably a C8 oxo alcohol. Where the ratio of the concentration of water relative to amine oxide exceeds about 0.05, a highly water and hydrocarbon soluble alcohol, preferably i~opropanol, also should be added.

DETAILED DESCRIPTION OF THE INVENTION

The present invention i9 directed at a fuel composition and a gasoline additive package which has been found to be particularly effective in reducing and/or eliminating injector fouling. The present in-vention is directed at a fuel compri~ing:

A. gasoline;

B. an anti-fouling agent having the following structueal formula:

1~9871 I

R 1 N > O
I

where Rl is C6-C24 alkyl, aryl, cycloaliphatic, heterocyclic, substituted alkyl, ~ubstituted aryl; R2 and R3 independently are Cl-C24 alkyl, aryl, sub-stituted alXyl or aryl, cycloaliphatic, heterocyclic, and mixtures thereaf; and, C. a demul~ifying agent selected from the group consisting of:

i. a ~atty acid alkyiamine reaction 2roduct;

ii. a ~olution of an oxyalkylated alkylphenol formaldehyde resins and polyglycols; and mixtures thereof.

Prefesred anti-fouling agents include compounds whe~ein: R1 is C6-C20 alkyl, or al~ylated aryl; and R2 and R3 independently are hydroxy substituted Cl-C12 alkyl. Particularly ,oreferred compounds are compounds wherein Rl comprises a Cg-C1g substituent. The additive preferably is selected from the group consisting of bis (2-hydroxy ethyl) coco-amine oxide, ois(2-hydroxy ethyl~ stearylamine oxide dimethylcocoamine oxide, dimethyl hydrogenated tallow amine oxide, dimethylhexadecylamine oxide and mixtures thereo~. These additives are prepared in accordance with known techniques, such as disclosed in U.S. Patent 3,387,953. A particularly preferred anti-fouling agent ~1 12~987~

is bis(2-hydroxy ethyl) cocoamine oxide.

The following Comparative Examples and Examples demonstrate the utility of the anti-fouling agent in reducing and/or eliminating fuel injector fouling. In the following Comparative Examples and Examples, the octane rating of the fuel utilized is the posted octane rating which is defined as:

Research Octane + Motor octane COMPARATIVE EXAMPLE I

In this test three 1985 Oldsmobile 98's having electronically con~rolled, fuel injected, 3.8 liter, six cylinder engines were driven on a commer-cial, unleaded, 87 octane reference fuel having a detergent concentration of 8.5 ptb for approximately 3500 miles under the following driving cycle: 0.5 hours city-type driving, 0.5 hour engine off, 0.5 hour high-way driving, 0.5 hour engine off. Driveability on all four vehicles became poor to very poor. The vehicles then were driven for 300 miles with a commercial premi~m grade 92 octane unleaded fuel containing 2.S
times the detergent used in the above reference fuel.
Driveability remained unchanged. The data in Table I
below show that there wa~ still a marked reduction in fuel flow indicating that a high level of deposit was unaffected by the detergent even at the high treat rate. The percent fuel flow reduction was determined by measuring the volume of a mineral spirit tnat flowed through the injector under predetermined standardi~ed 8~71 conditions, including fuel pressure, puise width and duty cycle. The percent reduction is calculated using the formula:

% Reduction = Vclean ~ Vdirty x 100%
Vcleab where Vclean and Vdirty are the mea~ured volumes of mineral spirit passed through the clean and dirty fuel injectors.

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~2~387~

Fro~ Table I it can be seen that this con-ventional, known carburetor detergent was ineffective in removing deposits from injector ports and in fact permitted deposits to form.

COMPARATIVE EXAMPLE r I

A 1985 Chrysler LeBaron equipped with a 2~2 liter turbocharged engine having electronically con-trolled fuel injection wa~ driven for 1300 miles on a mileage accumulation dynamometer using a typical regular grade, 87 octane, unleaded, detergent-free gasoline. The driving was based on repetition of the following cycle: 30 minutes city driving, 30 minutes engine off, 30 minutes highway driving, 30 minutes engine off. The driveability became very poor as typified by rough idle and severe he~itation. The hydrocarbon emissions measured before the catalytic converter were 321 pp~ at engine idle. The injector fouling was mea~ured u~ing a pres~ure differential test. In this test the fuel rail is pre~surized to 49 psig and an injector i~ pulsed for 0.5 seconds. The pre~sure drop, or leakdown P, is indicative of how readily the fuel flows, i.e., the higher the number, the less the injector is obstructed. In this vehicle the pressure differential for a clean injector under these conditions is 19-22 psig. This data i~ set forth below in Table II.

EXAMPLE I

Following the test set forth in Comparative Exa~ple II, the vehicle was refueled with the same fuel except that the fuel also contained 10 ptb of bis(2-hydroxy ethyl) cocoamine oxide (HECO1. The vehicle then was driven on the ~ollowing cycle: 15 ~inutes city ~2~871 driving, 30 minutes highway driving, 15 minutes city driving, 2 hours enqine off. This test continued until 270 miles were accumulated on the vehicle. At the end of thiC test period the driveability was very good. The hydrocarbon emissions at idle before the catalytic converter were reduced to 200 ppm. The percent in-jector flow reduction and the pressure differential were significantly improved as set forth in Table II.

From the data of Example I and Table II it can be seen that the use of a relatively low concen-tration of HECO was able to produce a significant im-provement in driveability. The idle emissions were significantly reduced and the pressure differential and percent flow reduction of the flow injectors were re-turned to "as new" conditions after a relatively few miles of driving.

12~9871 I
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a c~ z o ~2~3871 As shown by the following Comparative Example3 and Example, bis (2-hydroxy ethyl) cocoamine oxide also was effective in preventing the build-up of fuel injector tip deposits.

COMPARATIVE EXAMPLE III

In this Comparative Example, four 1985 Chrysler Le3arons equipped with four cylinder, electronically controlled, fuel injected, turbocharged, 2.2 liter engines were driven on mileage accumulation dynamometers under the following conditions: 0.5 hour city-type driving, 0.5 hour engine off, 0.5 hour high-way type driving and 0.5 hour engine off for 4,000 miles. The control car~ ran on a regular grade, 87 octane, detergent-free, unleaded fuel. Following the test, the percent flow reduction was measured u~ing the procedures previou31y cet forth hereinabove. The teQts were repeated in four different run~ (same make and model). The resultQ of the~e tests are set forth in Table III below.

EXAMPLE II

A 1985 Chrysler LeBaron, similar to that set forth in Comparative Example III was used in this test which was conducted under the same condition~ set forth in that Comparative Example. The gasoline used during this tect was the same as that used in the control cars, but with the further addition of 10 ptb of bis(2-hydroxy ethyl) cocoamine oxide (HECO). The results of these tests are also set forth in Table III
below. From a review of these tests it can be seen 12~3871 that the addition of a relatively low concentration of HECO was able to prevent a significant reduction in the fuel injector ~low rate.

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12'`~871 COMPARATIVE EXAMPLE IV

In this test a 1985 Chrysle~ LeBarOn naving a four cylinder, turbocharged, 2.2 liter engine with electronically controlled fuel injection was operated for 2,002 miles on a mileage accumulation dynamometer simulating alternating driving and engine-off cycles.
The fuel utilized was typical of a regular grade, 87 octane, unleaded fuel containing 8.5 ptb of the same detergent used in Comparative Example I. ~ollowing the completion of this te~~t, the percent flow reduction through the fuel injector ports was measured by the method previou ly described herein. A3 shown in Table IV below the use of this conventional carburetor detergent was ineffective in preventing injector fouling.

EXAMPLE I r I

A vehicle simila~ to that utilized in Comparative Example IV was utilized in thi~ Example under tha same operating condition~. The fuel utilized was ~imilar but with tha replacement of the conven-tional carburetor detergent by 10 ptb of bis(2-hydroxyl ethyl) cocoamine oxide. The vehicle was driven for 9,600 mile~ under the same sequence set forth in Compa~ative Example IV. The biR(2-hydroxy ethyl) cocoamine oxide wa~ able to prevent any significant flow reduction in the fuel injectors as shown by data pre~ented in Table IV.

i2n~8~71 O ~D O
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12~9871 From this Table it can be seen that the use of a relatively low concentration of HECO was able to prevent any significant buildup of injector tip de-posits. By comparison, the use of a conventional carburetor detergent at approximately the same rate was unable to prevent a relatively rapid deposit build-up of injector tip depositR.
.

While the data presented above has demonstrated the utility of the anti-fouling agent in gasoline, the anti-fouling agent also may be of utility in other fuels, such as diesel fuel.

While the pre~ently described anti-fouling agent may be used alone, it also may be desirable to utilize the present invention in combination with a demulsifier to facilitate the separation of the ga~oline from any foreign substances which may be present in the distribution system, ~uch as water and sediment.

The water, if any, typically has a pH
ranging from about 7 to about 12. Thus, a demulsifier for us~ with the anti-fouling agent preferably should be effective over this pH range. The following Comparative Exa~ples and Example~ demonstrate the utility of a demul~ifying agent selected from the group consi~ting of:

A. a fatty acid alkylamine reaction product;

B. a solution of oxyalkylated alkylphenol formaldehyde resins and polyglycols; and mixtures of A
and B above.

12~9871 COMPARATIVE EXAMPLE V

~ n this Comparative Example the effective-ness of various commercially available demulsifying agent3 were tested in a 90 wt.% fuel - 10 wt.% water system. The fuel contained 10 ptb HECO and 1 ptb of the various additives noted below. The effectivene~is of the various demul~ifying agents wa~ reached using a Multiple Contact Emul~ion Test. In thi-~ test 10 ml of di-~tilled water was added to separate half-pint bottles. To each bottle was added 100 ml of gasoline.
The bottles were capped, placed on their side~ in mechanical shaker and agitated at approximately 28 cycles per minute for five minutes. The bottles the were placed upright in a dark location and allowed t ~tand for 24 hours. The mixture then was rate.
con~idering the gasoline layer, the water layer and the interface u~ing the rating scale set forth in Table V
below. After the ratings were completed, the gasoline level was ~ucked down to a level about 1/4 inch above the emulsion layer without disturbing the interface or water layer. The withdrawn fuel was discarded and 100 ml of fresh gasoline was added to each bottle. The mixture was then shaken and the test repeated for a total of ten times (i.e. a total of about 10 days) or until it became apparent that the emulsion forming tendencies had exceeded acceptable levels of 3 or lower. The trade names of the commercially available additive utilized, the worst ratings of each mixture ar.d the time period before each test was terminated are set forth in Table VI below.

RATING SCALE POR REPORTING EMULSION TEST REUSLTS

RATING DESCRIPTION OF EMULSION
O No skin or interface 1 Slight skin on interface - not completely continuous 2 Thicker ~kin on interface - ~sually completely continous 3 Incipient emulsion 1/8 a~ thick as water layer 4 Emulsion 1/4 a~ thick as water layer Emulsion 3/8 as thick as water layer 6 Emulsion 1/2 as thick as water layer 7 Emulsion 5/8 as thick as water layer 8 Emulsion 3/4 as thick as water layer 9 Emulsion 7/8 as thick as water layer Emulsion completely filling water layer Emulsion of ~aximum severity 12~987~

TABLE VI
EMuLsroN TEST RESUL~S

WORST
DEMULSIFIER DESCRIPTION RATING DAYS RUN
None 6 10 Tolad T-292 4~5 5 Nalco 5 or 6RD871 7 6 - 26a -TABLE VII
DESCRIPTION OF DEMULSIFIERS LISTED IN TABLE VI

Demulsifier Description Tolad T-292 Oxyalkylated alkylphenol formaldehyde resins in aromatic hydrocarbons and isopropanol Tolad T-347 Oxyalkylated alkylphenol formaldehyde resins and acylated polyglycols in aromatic hydrocarbons and methanol Tolad T-370 Polyglycols in aromatic hydrocarbons Nalco 5450 Hydrocarbon blend of alkylphenol formaldehyde resin polyoxyalkylene polyether Nalco 5451 Polyglycolated polyol esters and polyglycolated alkylphenol/formalde-hyde resin in aromatic solvent Nalco 5452 Polyolpolyethers and oxyalkylated alkylphenol/formaldehyde resin adducts in aromatic solvent Nalco 5453 Oxyalkylated alkylphenol/formaldehyde resin adducts in aromatic solvent Nalco 85BD-194 Ethoxylated nonyl phenol/formaldehyde resin in hydrocarbon solvent :`-87~

EXAMPLE IV

A ga~oline-distilled water sample having 10 ptb of HECO similar to that of Comparative Example V
was utilized. However, in place of the demul~ifiers listed in Table VI the following additives were used alone or in combination.

Additive A - Nalco 3BD829 ~uel Dehazer, manufactured by Nalco Che~ical Company, Oak Brook, Illinois, which comprises a fatty acid alkylamine re3ction product and methanol in a hydrocarbon ~olvent.
~' Additive B - Tolad T-326 manufactured by the Tretolite Division of Petrolite Corporation, St. Louis, Missouri.
This additive comprises oxyalkylated alkylphenol-formaldehyd~ resins and polyglycols in aromatic naphtha. The Multiple Contact Emulsion Test previously described was utilized to determine the effectiveness of the~e demulsifiers. These test results are summarized in Table VIl below.

12~9871 TABLE VII
EMULSION TEST RESULTS

DEMULSIFIER WORST
DESCRIPTrONCONCENTRATION RATING DAYS RUN
Additive A1 ptb 0 10 Additive 81 ptb 2 10 Additive A0.5 ptb Additive ~0.5 ptb 12~9871 From a review of Table VII, it can be seen that both Additive A and Additive 3 were effective. It also can be seen that Additive A and the same total concentration of a mixture of Additive A and Additive B
were more effective than Additive ~ alone.

EXAMPLE V

A sample comprising 100 ml portion~ of gasoline containing 10 ptb of HECO and a total of 1 ptb of Additive A, Additive B or a combination of Additive A and Additive B wa tested with another typical gasoline contaminant, refinery process water bottoms having a pH of 10. A sample containing 90 wt.% of this fuel and 10 wt.% of the proceqs water bottoms was utilized. The Multiple Contact Emulsion Te~t described in Comparative Exzmple V was utilized with one modification. The sample was shaken at 1 1/2 hour intervals rather-than 24 hour intervals. Thus, this procedure is more severe than the test method of Comparative Example V. The results of this test are set forth in Table VIII below.

i2~3871 TABLE VIII
MODIFIED EMULSION TEST RESULTS

NUMBER OF
DEMULSIFIER WORST GASOLINE
DESCRIPTIONCONCENTRATION RATING TREATS
Additive A1 ptb 7 10 Additive B1 ptb 2 10 Additive A0.5 ptb Additive B0.5 ptb 12~87~

From this table it can be seen that Additive B and a mixture of Additive A and Additive B were more effective than Additive A alone.

Demulsifier Additive A was thuq found to be more effective than Additive B with neutral water, while Additive B was much more effective than Additive A when the water wa~ basic. The combination of these additives is particularly preferred, since it was highly effective in both neutral and basic conditions.

Where the presently described invention is used as a gasoline additive, the additive pac~age may be added to the gasoline at any point after the gasoline has been refined, i.e., the additive package can be added at the refinery or in the distribution system. To assure a relatively constant concentration of the additive package in the gasoline and to assure that none of the additives precipitate from the addi-tive package, diluent solvents typically are combined with the additive package to produce an additive con-centrate which is metered into the fuel.

The amine oxide typically has water present from the manufacturing process. While it is possible to remove most of the water, removal of the water to relatively low levels, i.e. a ratio of about 0.02 to about 0.04 of water to amine oxide, adds complexity to the manufacturing process. Therefore, the amine oxide is commercially available as a solution which has the following composition:

Approximate Additive Concentration, Wt.

isopropyl alcohol 45 water 6-8 To provide an additive concentrate which is pumpable and which does not precipiate even in winter conditions, the concentrate preferably should have a cloud point below about -20F and a pour point of less than -40F.

Typically, the additive package is diluted in the range of about 1:1 to about 10:1 with diluent solvent, preferably about 5:1 to facilitate metering and to provide a concentrate having the desired cloud and pour points.

COMPARATIV~ EXAMPLE VI

In this test, the additive package was diluted about 4.9:1 with a diluent which comprised about 90 wt.~ xylene and 10 wt.~ isopropanol. The resulting concentrate had the following composition:

Approximate AdditiveConcentration, Wt.%
Amine Oxide ~.00 Xylene 73.50 isopropyl alcohol 15.84 water 1.00 ~emulsifier ~0.83 Demulsifier B0O83 100 .(~0 Twenty-five ml. of this additive concentrate were mixed with 25 ml. of gasoline and 10 ml. of refinery water bottoms in an 8 inch centrifuge tube with a narrow tip to simulate the conditions which 12Qg87~

could occur in the field before the additive concentrate is completely mixed with the gasoline. An excess of water was included for illustrative purposes as set forth below.

The tube was placed in an ultra~onic bath at room temperature and subjected to ultrasonic fre-quencies for about five minutes to cause intimate mixing. After removal from the ultrasonic bath and centrifugation to facilitate separation, it was noted that three phases had formed, two organic phases and a water phase. Formation of two organic phases is not desirable, since this was found to result in uneven distribution of the HECO between the layers. In addi-tion, the second organic layer which ha~ a much higher HECO concentration, tends to adhere to the surfaces, resulting in additive los~ and potential contamination of subsequent hydrocarbon products that might contact these ~urfaccs.

EXAMPLE VI
.

In this Example, the ~ame additive package wa-~ used a~ wa~ u~ed in Comparative Example VI. The additive package again wa~ diluted with about 4.9 parts solvent. However, in thi~ Example the isopropanol in the diluent solvent was replaced with an equal weight of C8 oxo alcohol. The concentrate had the ollowing composition:

12~871 Approximate AdditiveConcentration, Wt.
Amine Oxide 8.00 Xylene 73.50 C8 oxo alcohol 8.17 i~opropyl alcohol 7.67 water 1.00 Demulsifier A0.83 Demulsifier B0.83 100.00 Twçnty-five ml. of this additive concentrate were mixed with 25 rnl. of gasoline and 10 ml. of refinery water bottoms and intimately mixed in an ultrasonic bath as described in Comparative Example VI.
After intimate mixing and centrifugation to facilitate separation, it was noted that only two layers, an organic layer and a water layer were formed.

~ rom thia Example it can be ceen that the replacement of at least a portion of the isopropanol by a higher molecular weight alcohol, preferably a C4-C12 alcohol, mOrQ preferably an oxo alcohol and most preferably a Cg oxo alcohol, prevented the formation of two organic layers. As used herein the ter~ "oxo alcohol~ refers to one or more branched chain aliphatic alcohols prepared by the reaction of carbon monoxide and olefins followed by hydrogenation of the resulting aldehydes.

A serie~ of teat~ also were run utilizing different solvents to determine the cloud point of the resulting additive concentrates. Those test~ generally were conducted in accordance with ASTM test method D2500, the disclosure of which is incorporated herein by reference. These results are presented in Table rx.

o~ Oe E
O o L~ a.~ ~ o ~ ... ., _. ~D ~ O V ~ ~ a~ O ~ ~
o ~ ~ ~ v I_I ~ ~ v :~
O O E O E
_~
C~ U V

,a~
.
0 U~
U~ _~
O E
C~
d v o o oo o o o o 3 . o o oo o o o o E~

a~ ~ Oc E~ 'v ~ a~
~ .~ C ~ o o oo o o o o O 0 ._,.,.,o oo o o o o o O E~ ~
O co a~ ~~ a~
O C~ O

~ O
Ll ~ ~t ~D --I ~t't V ~_1 c t~ ~C o a~o 1~ o O C O
C O
O ~ O
C.) .) ~ 0 ~0 V ~ Ç
.,. o ~ ,_ C~
o V ~ I~ o o oC~ o C ~I _~
~ 0 ~4 o U~
~ ~-o o r~ o ' .. . . .
~ ~ ~ ~ _, ~ r~ u~
X a~

~ rom a review of Table IX, it can be seen that the combination of a solvent system comprising xylene, isopropyl alcohol and C8 oxo alcohol produces an additive concentrate which has a cloud point below about -46~ for the point tested. 8y comparison, use of a solvent system comprising only xylene and C8 oxo alcohol produced a system which had acceptable cloud points only over a very narrow concentration range.
Therefore, the use of a mixed alcohol solvent system is desirable to produce a concentrate having good low temperature properties without the tendency to form a second organic layer.

Multiple Contact Emulsion ~est~ were con-ducted in a manner similar to that set forth in Comparative Example V for ga~oline samples. The tests were run on both unleaded regular grade gasoline and unleaded premium grade gasoline containing 10 ptb HECO
and 0.5 ptb each of Demulsifiers A and B, to which 10 wt.~ terminal water bottoms having a pH of about 7 and 8, respectively, ha~ been added as previously described. The samples were shaken for 10 minutes at 180 cycles per minute. The bottle~ then were permitted to stand for the times indicated and rated. A~ ~hown by the data in Table X, the replacement of the i~opropanol by the combination of isopropanol with C8 oxo alcohol did not adver~ely affect the effectiveness of the demul~ifier package. Thus, a concentrate in-cluding a solvent system comprising isopropanol and C8 oxo alcohol has acceptable demul~ifying propertie~ and an improved cloud point relative to a solvent system comprising C8 oxo alcohol alone, when significant quantities of water are present. As previously noted, such a solvent system also does not promote the forma-tion of multiple organic layer~.

g7~

TABLE X
MULTIPLE CONTACT EMULSION TEST

FuelTime ~Hrs.) Emul~ion Ratinq Isopropano Isopropanol + C8 oxo Alone Alcohol Unleaded Regular 1 2 2 2g 2 2 Unleaded Premium 1 3 2-3

Claims (12)

1. A fuel composition for an internal combustion engine said engine composition comprising:

A. gasoline; and an effective amount of B. an antifouling agent having the formula wherein: R1 is C6 to C24 alkyl, aryl, cycloaliphatic, heterocyclic, substituted alkyl or substituted aryl; R2 and R3 independently are C
to C24 alkyl, aryl, substituted alkyl or aryl, cycloaliphatic or heterocyclic; and C. a demulsifier selected from the group consisting of:

i. a fatty acid alkylamine reaction product;

ii. a solution of oxyalkylated alkylphenol formaldehyde resins and polyglycols; and mixtures of i and ii.

2. The fuel composition of claim 1 wherein 1 is C6 to C20 alkyl, or alkylated aryl; and, R2 and independently are hydroxy substituted C1 to C12 alkyl.

3. The fuel composition of claim 2 wherein the fuel comprises unleaded gasoline.

4. The fuel composition of claim 3 wherein the demulsifier comprises:

A. a fatty acid alkylamine reaction product; and, B. a solution of oxyalkylated alkylphenol formaldehyde resins and polyglycols.

5. A fuel additive concentrate for internal combustion engines, said additive comprising:

A. about 5 to about 50 wt.% bis(2-hydroxy ethyl) cocoamine oxide;

B. about 0.25 to about 10 wt.% fatty acid alkylamine reaction product; and, C. about 0.25 to about 10 wt.% oxyalkylated alkylphenol formaldehyde resins and polyglycols;

D. about 40 to about 95 wt.% solvent.

6. The fuel additive concentrate of claim 5 wherein the solvent comprises xylene and an alcohol.

7. The fuel additive concentrate of claim 6 wherein the alcohol is selected from the group consisting of isopropanol, C4-C12 alcohols, and mixtures thereof.

8. A fuel additive concentrate for internal combustion engines, said additive comprising:

A. about 5 to about 50 wt.% bis(2-hydroxy ethyl) cocoamine oxide;

B. about 0.25 to about 10 wt.% of a demulsifying agent; said demulsifying agent being selected from the group consisting of:

i. a fatty acid alkylamine reaction product;

ii. a solution of oxyalkylated alkylphenol formaldehyde resins and polyglycols; and mixtures of i and ii; and C. about 40 to about 95 wt.% of a solvent comprising:

i. xylene; and ii. a C4-C12 alcohol.

9. The fuel additive of claim 8 wherein the solvent further comprises isopropanol.

10. A fuel composition for reducing and/or preventing fouling in a multiport electronically controlled fuel injection system for an internal combustion engine, said fuel composition comprising:

A. about 20 to about 60 ppm bis(2-hydroxy ethyl) cocoamine oxide;

B. about 0.5 to about 4 ppm fatty acid alkylamine reaction product; and, C. about 0.5 to about 4 ppm oxyalkylated alkylphenol formaldehyde resins and polyglycols.

11. The fuel composition of claim 1 wherein the antifouling agent is present in an amount of about 2 to about 200 ppm by weight of total composition.

12. The fuel composition of claim l or 11 wherein the demulsifier is present in an amount of about 0.1 to about 40 ppm by weight of total composition.