US 3382181 A
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United States Patent M COMPOSITION FOR ENGINE DEPOSIT REMOVAL Paul E. Oherdorfer, Jr., Devon, Wilmington, Del., assignor to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey No Drawing. Continuation-impart of application Ser. No. 476,172, July 30, 1965. This application Dec. 2, 1966, Ser. No. 598,595
9 Claims. (Cl. 252-470) ABSTRACT OF THE DISCLOSURE The present disclosure relates to a carburetor cleaner which cleans the internal and external deposits therefrom. The cleaning composition contains a cyclic carbonate inner ester as the major active component with certain solvents, namely a C to C olefin, a mononuclear aromatic hydrocarbon and a polar solvent of an ester, glycol ether or mixtures thereof.
This application is a continuation-impart of application Ser. No. 476,172, first filed July 30, 1965, by Paul E. Oberdorfer, In, and now abandoned.
The present invention relates to removing internal and external deposits from fuel and air intake systems and from the combustion chambers of internal combustion engines.
The formation of gummy deposits on the internal and external parts of internal combustion engine fuel and air intake systems is an important problem alfecting efficient engine operation. For example, the formation of these deposits on the internal parts of a carburetor can cause sticking of the automatic choke, plugging of the air bleeds, fouling of venturi, restriction of idle air flow around the throttle blades and other conditions which adversely affect engine performance. The formation of deposits on the external parts of a carburetor cause automatic choke linkages, fast idle links and the like to behave sluggishly or to stick.
The formation of carbonaceous deposits on surfaces in the engine combustion chambers is also an important problem affecting both spark, ignition and compression ignition engines. Combustion chamber deposits cause increased engine wear, pro-ignition and engine knocking and increase the octane requirement of an engine.
A composition is shown in US. Patent 2,935,479 issued to Paul E. Oberdorfer, Jr., that reduces the accumulation of deposits in engine fuel and air intake systems and in engine combustion chambers. The active ingredient of this composition is a cyclic carbonate inner ester such as propylene carbonate. The cyclic carbonate inner ester loosens and dissolves engine deposits and enables the deposits to be exhausted from the engine.
The present invention maintains the desirable internal cleaning properties of the cyclic carbonate inner ester compositions but has the additional advantage of being able to remove the external deposits on fuel and air intake systems, which removal provides two benefits: (1) improved function of the system because of the freeing of external linkages and (2) renewed appearance of the cleaned system.
The previous compositions containing cyclic carbonate inner esters were not capable of removing the deposits 3,382,181 Patented May 7, 1968 from the external parts. The internal and external deposits are of entirely different types. The internal deposits are essentially polar in nature whereas the external deposits are essentially non-polar in nature. Previous cyclic carbonate inner ester compositions suitable for cleaning the fuel and air intake systems in a single direct application were all polar solvents which had no effect on the external deposits.
In order to be effective for removing the polar deposits in a single application the formulation must contain at least 10 volume percent of cyclic carbonate inner esters.
The first attempt made was to dissolve the cyclic carbonate inner ester in certain hydrocarbons of the naphtha type, i.e., gasoline, since this would have the desirable non-polar solvent properties, however, it was found that the propylene carbonate was soluble in amounts up to only 1% by volume and other cyclic carbonate inner esters were soluble only in amounts up to 2% by volume. The use of gasoline per se would be unsuitable because of the danger of fire and the low solubility of the cyclic esters in gasoline, i.e., only 1 to 2%.
It was anticipated that C to C saturated aliphatic hydrocarbons would be suitable solvents for the nonpolar deposits, however, these hydrocarbons were found to be insoluble with the carbonate inner esters. Thus neither C to C saturated aliphatic hydrocarbons nor naphtha type materials are suitable in the compositions of the present invention.
It was found that substituted mononuclear aromatics, particularly mixed xylenes, were miscible in all proportions with the range of cyclic carbonate inner esters employed, however, the aromatics alone were not good enough solvents to remove the non-polar deposits.
It was found quite surprisingly that the substituted mononuclear aromatics were capable of solubilizing the C to C olefins, but not the saturated C to C hydrocarbons. The C to C saturated hydrocarbons could not be solubilized with the cyclic carbonate inner esters in the desired proportions of inner ester to be employed.
It was determined that suitable mononuclear aromatic hydrocarbons were those having from 1 to 4 substituents said substituents being selected from the group consisting of hydrocarbon chains having no more than 4 carbon atoms and chlorine atoms. Examples of suitable aromatic solvents include toluene, xylene, mesitylene, durene, ethylbenzene, 1,2,3,4-t-etraethylbenzene, l-ethyl-3-isopropylbenzene, chlorobenzene, chlorotoluene, 1,2,3,4-tetrachlorobenzene and the like or mixtures thereof.
Suitable C to C olefins include, for example, hexenes, heptenes, S-methyl-l-heptene, S-methyl-l-hexene, 2,3,3,4-tetramethyl-l-pentene, Z-undecene, cyclohexene and the like or mixtures thereof.
The cyclic carbonate inner esters which are used in this invention have the formula:
wherein each R is hydrogen or a hydrocarbon group. The hydrocarbon groups can be alkyl, aryl, aralkyl and alkaryl groups preferably having about 1-6 carbon atoms per group. Cyclic carbonate esters having fewer carbon atoms are generally more effective in reducing polar deposit accumulation than are esters having more carbon atoms. It is preferred that the total carbon atoms in the hydrocarbon substituent groups not exceed about 6. The use of propylene carbonate is especially preferred in carrying out the invention. Examples of other cyclic carbonate inner esters which are suitable are ethylene carbonate, butylene carbonates, amylene carbonates, phenyl ethylene carbonate, and the like as well as mixtures of cyclic carbonate inner esters.
In the present invention the cyclic carbonate composition is applied directly to carburetor, internally and externally. Preferably the cleaning composition is applied from a plastic squeeze bottle or from an aerosol can using a nozzle to direct the stream of cleaner.
Cyclic carbonate inner esters are fairly viscous liquids with high surface tension. For example, propylene carbonnate has a kinematic viscosity at 100 F. of 1.69 centistokes and a surface tension of 43.4 dynes per cm. at 68 F. Thus since in the practice of this invention the deposits are to be removed from relatively cool portions of the engine, e.g., from the upper portions of the carburetor air horn, it is desirable to lessen the viscosity and surface tension of the cyclic ester by mixture with less viscous polar organic solvents which improve the penetration of the cyclic ester on polar deposits. It is especially desirable to use liquids with the cyclic carbonate esters which are substantially lower boiling than the cyclic esters. These last liquids improve the penetration of the cyclic esters in the cooler parts of the engine such as the internal 30 and external parts of the carburetor while in the hotter parts of the engine the solvents evaporate leaving the cyclic esters which are most needed on these parts. The non-polar solvents are also, for these same reasons, lower boiling than the cyclic esters. 5
Mixtures of one or more polar solvents with the cyclic esters, the mononuclear aromatics and olefins can be used to increase the penetration of the cyclic esters on the polar deposits. Suitable polar solvents are selected from the group consisting of (1) an ester having the structure R ii-oR where R is hydrogen or a hydrocarbon radical having 1 to 3 carbon atoms and R is a hydrocarbon radical having 1 to carbon atoms; (2) a glycol ether having the structure where R is a hydrocarbon radical having 2 to 3 carbon atoms, R is hydrogen or a hydrocarbon radical having l to 4 carbon atoms and R is a hydrocarbon radical having 1 to 4 carbon atoms; and (3) mixtures thereof. Examples of the polar solvents that may be used include esters such as methyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, amyl acetate, methyl proprionate, ethyl propionate, ethyl butyrrate, isopropyl butyrate; glycol ethers such as ethylene ether, propylene glycol diethyl ether, propylene glycol diisopropyl ether and the like.
Suitable cleaning compositions contain by volume 10- of a cyclic ester, 5 to of a C to C olefin, 5 to of a mononuclear aromatic hydrocarbon and 5 to of a polar solvent selected from the group consisting of an ester, a glycol ether and mixtures thereof.
A preferred cleaning composition is one that contains by volume a cyclic ester 10-60%, a C to C olefin 5- 70%, a mononuclear aromatic hydrocarbon 575%, an ester 5-75% and a glycol ether 550%. The use of the glycol ethers was found (1) to increase the range of solubilities of the olefins and cyclic esters, (2) to provide a solvent of intermediate polarity between the polar cyclic esters and the non-polarolefins and to reduce the amount of aromatic hydrocarbons necessary, for obtaining miscibilities. Thus, by replacing a portion of the aromatic hydrocarbon, i.e., diminishing the relative proportion thereof, it is more rapidly diminished in total concentration by evaporation during the cleaning of the internal parts leaving essentially polar solvents which are preferred for the internal cleaning.
An example of a preferred composition is one containing propylene carbonate, propylene trimer, xylene, ethyl acetate and ethylene glycol monoethyl ether in the ranges previously mentioned.
Particularly preferred compositions according to present invention that have been found to have excellent properties for cleaning the internal and external parts of fuel and air intake systems for internal combustion engines as well as being relatively economical are those containing by volume 15 to 35% propylene carbonate, 10 to 40% propylene trimer, 5 to 23% mixed xylenes, 5 to 35% ethyl acetate, and 5 to 25% ethylene glycol monoethyl ether.
EXAMPLE I Eight late model automobiles that had been run on various blends of gasoline were selected in order to test the cleaning ability of a composition according to the present invention.
;T he composition employed was Volume percent Propylene carbonate 25 Propylene trimer 25 Xylene l5 Ethyl acetate 25 Ethylene glycol monoethyl ether l0 TABLE I Milagc on Improvement Automobile Unelcancd Carburetors Appearance Performance W: Tempest--.-. 0, 000 Removed residual Improved engine idle.
varnish and gums. 64 Pontiac 4, 0 0 -....do Corrected choke operation.
Do 12, 000 -.do.. Do. 63 Chevrolet... 24, 000 .....do Improved idle and warmup perionnanee. 130.... .dO '52 Pl mouth.-- 83, 000 .....do 62 Corvair 62, 000 .....do.. Improved cold weather starting. '02 Cadillac do glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl 75 EXAMPLE II A 1955 Oldsmobile with over 90,000 miles presented a particular problem since its carburetor was in disrepair and thoroughly covered inside and out with varnish and oil deposits. Adjustment of the idle jets produced virtually no response in idle characteristics. The secondary ven turi system (4 bbl. carburetor) was gummed up to the extent that the air bleeds were sealed shut. The automatic choke was gummed tight in the three-quarter closed position. The carburetor was cleaned with 8 ounces of the formulation of Example I using a plastic squeeze bottle and nozzle.
The idle jet pasages were cleaned by removal of the needle assemblies and squirting the formulation through the idle passages. All external air bleeds likewise were cleaned in this fashion. The automatic choke vacuum system which had been plugged shut was cleaned by forcing a stream of the formulation through the passage while the engine was-idling. The remainder of the internal air passages were cleaned by spraying a stream of the formulation on them through the carburetor throats, The external linkages were cleaned with the stream of cleaner and required about two ounces of the cleaner.
As a result of this cleaning operation, which was performed in situ, i.e., without removal or disassemblv of the carburetor, a vastly improved appearance and restoration of the carburetor to nearly original performance was achieved. The only part replacement necessary was a rather inexpensive accelerator pump leather boot.
In order to determine the comparative effectiveness of the present composition with those presently available on the market two of the leading carburetor-top engine cleaners were selected. Composition A was found to contain diacetone alcohol as the active ingredient, mixed xylenes as the carrier and about 1% lube oil. Composition B 2 had ethylene glycol monobutyl ether as the active ingredient, aromatic hydrocarbons as the carrier and about alkyl ammonium alkyl phosphate and heavy oil. The formulation of Example I was used to demonstrate the present invention.
The following tests were performed.
Cleaning ability.Each formulation was sprayed on adjacent portions of a Carter Ball and Ball one-barrel carburetor which had normal deposits from having been run on a regular grade of gasoline, The use of a single carburetor eliminated variations in deposits nature from carburetor to carburetor. The results of the test are recorded in terms of the visual observation of the cleaning ability of each formulation.
Volatility-One ml. of each formulation was placed on a 1 /2 inch water glass and heated to 210 F. on a steam bath. The results are recorded in hours to evaporate the sample to less than 1% of original volume and hours to dryness. Measurements of percent volume remaining at 90 and 180 minutes were also made. Exceedingly fast evaporation indicates insufiicient time to penetrate the deposits to rinse them away. Extremely slow evaporation allows dust and dirt to build up and recreate sluggish operation. A sticky residue is undesirable since it also recreates the deposit problem.
Kinematic viscosity.Recorded in centistokes. Too high a viscosity (over 5) prevents easy application of the cleaner formulation to the internal and external parts of the carburetor.
Surface tension.Measured in dynes/ cm. High surface tension (over 30) also inhibits the effectiveness of the cleaner.
Oil cutting-In this test the time required for /2 ml. of each formulation to drain /2 ml. of heavy oil from a 1 ml. necked down pipette was measured. This test is designed to show the effectivness of the present composition to dissolve non-polar type deposits.
The results of the tests are set out in Table II.
Composition A-Gumout. Composition -BG.M. Top Engine Cleaner Gr. 8.800, #1050002.
TABLE II Composition Example I A B Test:
Cleaning Ability 5 Volatility:
Hours to 1% original volume..- 3. 0 0. 3 96. 0 Hours to Dryness 96. 0 4 96.0 96. 0 Percent original volume at 90 min. 1 Percent original volume at 180 min 1 1 10 Kinematic Viscosity, Centistokes at 100 F 0.9 0.9 7. 9 10 Surface Tension, dyne/cm 26. 5 31. 1 30. 8
Oil Cutting, Time for ml. of solvent to drain ml. oil
1 Fast, effective. 2 Fast, partially effective. 3 Slow, partially effective. 15 4 Sticky residue.
5 2 min., 27 sec. 8 3 min., 57 sec. 7 3 min., 44 sec.
Although compositions A and B performed in a satisfactory manner, it is readily apparent that the composition according to the present invention is superior in its cleaning ability and particularly in its ability to dissolve non-polar type materials.
The use of compositions according to the present invention not only reduces the octane requirement of internal combustion engines and results in more economical operation of such engines but will, along with proper adjustment of the engine, improve the combustion of hydrocarbon fuels and will aid in reducing atmospheric contamination resulting from such improper combustion.
1. A solvent composition consisting essentially of by volume: about 10 to 60% of .a cyclic carbonate inner ester having the formula wherein R is selected from the group consisting of hydrogen, alkyl, aryl, aralkyl and alkaryl hydrocarbon groups having from 1 to 15 carbon atoms per group, 5 to 70 of a C to cl3eole'fil'l, 5 to 75% of a mononuclear aromatic hydrocarbon having from 1 to 4 substituents selected from the group consisting of alkyl hydrocarbon chains having 1 to 4 carbon atoms and chlorine atoms, and 5 to 80% of a polar solvent selected from the group consisting of (1) an ester having the structure where R is hydrogen or an alkyl hydrocarbon radical having 1 to 3 carbon atoms and R is an alkyl hydrocarbon radical having 1 to 5 carbon atoms; (2) a glycol ether having the structure R*O-R OR where R is an alkylene hydrocarbon radical having 2 to 3 carbon atoms, R is hydrogen or an alkyl hydrocarbon radical having 1 to 4 carbon atoms and R is an alkyl hydrocarbon radical having 1 to 4 carbon atoms; and (3) mixtures thereof.
2. A solvent composition according to claim 1 wherein the polar solvent is a mixture of 5 to 75 of the ester and 5 to of the ether.
3. A solvent composition according to claim 2 wherein the cyclic carbonate inner ester is selected from the group consisting of ethylene canbonate, butylene carbonates, amylene carbonates, phenyl ethylene carbonate and mixtures thereof.
4. A solvent composition according to claim 3 wherein the C to C olefin is propylene trimer.
5. A solvent composition according to claim 2 wherein the ether is ethylene glycol monoethyl ether.
6. A solvenlt composition according to claim 2 wherein the ether is ethylene glycol monobutyl ether.
7. A solvent composition according to claim 2 wherein the mononuclear aromatic hydrocarbon is chloro'benzene.
8. A solvent composition according to claim 2 wherein the cyclic carbonate inner ester is propylene carbonate, the C to C olefin is propylene trimer, the mononuclear aromatic hydrocarbon is xylene, the ester is ethyl acetate and the ether is ethylene glycol mono-ethyl ether.
9. A solvent composition according to claim 2 consisting essentially of by volume: 15 to 35% propylene carbonate, 10 to 40% propylene trimer, 5 to 35% xylene, 5 to 35% ethyl acetate and 5 to 25% ethylene glycol monoethyl ether.
References Cited UNITED STATES PATENTS 5/1956 De LeW et al 252-172 5/1960 Oberdorfer et a1. 252-17O