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Publication numberUS3290130 A
Publication typeGrant
Publication dateDec 6, 1966
Filing dateDec 7, 1964
Priority dateDec 6, 1963
Also published asDE1259636B
Publication numberUS 3290130 A, US 3290130A, US-A-3290130, US3290130 A, US3290130A
InventorsAssmann Horst
Original AssigneeExxon Research Engineering Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Lubricant for two-stroke engines
US 3290130 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

United States Patent M 9 Claims. (CI. 44-58) The present invention concerns improved lubricating oils for gasoline engines of the type that are lubricated by mixing the oil with the fuel that is fed to the engine. Ordinarily this lubricating procedure is employed for gasoline engines that have a two-stroke cycle. A representative engine of this type is the well-known outboard motor for powering various types of boats. The twostroke-cycle engines are also employed for powering lawn mowers and certain small automobiles such as the Saab.

Usually when lubricating a two-stroke-cycle gasoline engine, the lubricating oil is mixed with the fuel fed to the engine in a ratio of 1 volume of lubricant to from about 15 to about 40 volumes of fuel. The mixture first enters the crankcase where the mixture of lubricant and unvaporized fuel contacts and lubricates the various moving surfaces including the bearings, pistons, piston rings, and cylinders. All of the lubricant that does not deposit on the surfaces in the lower part of the engine passes into the combustion chamber where it is burned along with the fuel. Experience shows that only about 20 percent of the lubricating oil that is added to the fuel actually serves to lubricate the engine, while the remainder of the oil is burned with the fuel without taking any part in the lubricating process. One disadvantage of this method of lubrication is that consid-- erable smoke and stench are created by the incompletely burned portion of the lubricating oil. If one attempts to minimize the production of smoke and stench by reducing the proportion of lubricating oil in the mixture of fuel and oil, defective lubrication of the engine occurs with consequent damage.

It has now been found in accordance with the present invention that if a particular combination of additive materials is incorporated in the lubricating oil, it is possible to operate a two-stroke-cycleengine with an oil-fuel mixture in which the proportion of lubricating oil is considerably reduced, i.e. to an oil-fuel ratio ranging from about 1 to 100 to about 1 to 200. This results in a marked reduction in the formation of smoke and stench from the exhaust from the engine without impairirlg the proper lubrication of the engine.

The combination of additives employed in the present invention for improving the lubricant for a two-stroke internal combustion engine comprises from about 0.2 to about 3 weight percent, preferably about 1 to about 2 weight percent of an alkaline earth metal organic sulfonate and a separate sulfur-containing organic compound in sufiicient quantity to supply in the range of from 0.01 to 2.0 weight percent of additional sulfur.

The latter sulfur-containing compounds are selected from the group consisting of sulfurized fatty oils, sulfurized unsaturated hydrocarbons such as olefins, olefin polymers and terpenes, and phosphosulfurized hydrocarbons.

Further improvement of the compositions results in many instances when there is also added from 0.1 to 5 weight percent, or preferably about 0.5 to 2 weight percent, of a zinc salt of a dialkyl dithiophosphoric acid. An animal oil or a vegetable oil such as sperm oil, lard oil, cottonseed oil, peanut oil, or the like; or a terpene or an olefin or olefin polymer; may be sulfurized by adding sulfur thereto, as for example, 5 to 40 percent sulfur, followed by heating at a temperature in the range of say .200 to 400 F. for 1 to 4 hours. Phosphosul- 3,290,130 Patented Dec. 6, 1966 furized unsaturated hydrocarbons such as terpenes or polyolefins can be prepared by reacting the hydrocarbon with from 5 to 30 weight percent of a sulfide of phosphorus such as P 8 under anhydrous conditions at temperatures of from about 150 to about 600 F. for from /2 to 15 hours. A specific example is the reaction product of a polyisobutylene of an average Staudinger molecular weight of about 830 with 15 parts by weight of P 5 for about 10 hours at about 450 F. The polyolefins may range in molecular weight from about 500 to about 200,000 Staudinger and may contain from 2 to 6 carbon atoms per olefin monomer, thus including polymers of ethylene, butylene, propylene or isobutylene, for example. The terpenes may include pinene, other turpentine hydrocarbons, citrene, and the like.

The metal sulfonates employed in this invention are the oil-soluble alkaline earth metal salts of high molecular Weight sulfonic acids obtained by the sulfonation of either natural or synthetic hydrocarbons. Natural hydrocarbon sulfonic acids are usually petroleum sulfonic acids obtained by treating lubricating oil base stocks or related petroleum fractions with concentrated or fuming sulfuric acid by well established procedures. These sulfonic acids usually have molecular weights in the range of about 300 to 700. Synthetic hydrocarbon sulfonic acids can be produced by sulfonating alkylated aromatic hydrocarbons, as for example the hydrocarbons obtained by alkylating benzene, toluene or xylene with olefins or olefin polymers.

Specific examples of sulfonates suitable for use in the present invention include a barium petroleum sulfonate of about 950 molecular weight, calcium C alkyl benzene sulfonate (from benzene alkylated with di-isobutylene), magnesium petroleum sulfonate of about 800 molecular weight, barium C alkyl benzene sulfonate (from ben zene alkylated with tetraisobutylene), calcium petroleum sulfonate of about 880 molecular weight, and calcium C alkyl benzene sulfonate derived from benzene alkyl-;

fonates wherein additional metal base in excess of that required for simple neutralization has been reacted With the sulfonic acids to form an alkaline product which is then blown with CO to reduce alkalinity.

The preparation of dialkyl dithiophosphoric acids is' well known in the art and simply involves reacting about 4 moles cf an aliphatic alcohol or a mixture of alcohols with 1 mole of phosphorus pentasulfi-de at temperatures in the range of from about to about 250 F. for from 1 to 6 hours. For use .in the present invention dialkyl dithiophosphoric acids prepared from alcohols having in the range of from about 3 to about 16 carbon atoms are contemplated. The dialkyl dithiophosphoric acids used in this invention include not only those made from a simple aliphatic alcohol such :as .isopropyl, normal butyl, normal decyl, and so forth, but also from mixed aliphatic alcohols such as the C or C :oxo alcohols obtained by reaction of olefins with carbon monoxide and hydrogen and subsequent hydrogenation of the resultant aldehydes. Also there may be used dithiophosphoric acids obtained from such mixtures as isopropyl alcohol mixed with unethyliso-butyl carbinol, a combination of primary amyl alcohol and isobuta-nol, a combination of lIIllXCd amyl alcohols and technical lauryl alcohol, a mixture of isopropyl alcohol and C ox o alcohol, and the like. Mixed acids obtained by reaction of individual alcohols separately with P 8 may also be employed in the preparation of the metal salts.

The lubricating oil components of the compositions of this inve-ntion should comprise clean burning base stocks having viseosities at 210 F. in the range of about 45 to 85 SSU. Preferably the base st-ock should be a naphthenic distillate (.eg. a C-oastal distillate) that has been extracted to a viscosity index of at least 60 although the viscosity index may be higher, e.g. 80 to 100* or more. Preferably the base stock should have a viscosity at 210 F. of from about 58 t-o about 75 SSU.

It is frequently desirable to include in the composition from 0.1 to 1 weight percent of an antioxidant and/or a corrosion inhibitor such as phenyl alpha naphthylamine, 2,6- i-tert. butyl p-cresol, 4,4-methylene bis(2,6-di-tert. butyl phenol), dimerized linoleic aci-d or the like. Particularly useful corrosion inhibitors are ethoxylated fatty acids or fiatty alcohols of from 12 to 18 carbon atoms containing from 2 to 7 ethoxy groups per chain, as for example ethoxylate-d lauryl alcohol, ethoxylated stearic acid, ethoxylated stearyl alcohol, ethoxylated tall-ow fatty acids, and the like.

The fuel component of the mixture of lubricant and fuel may be a conventional gasoline having in the range of from 1 to about 3 ml. of tetraethyl lead per gallon.

The benefits of this invention may be further appreciated when reference is made to the following examples:

Example 1 Several c-ompositions were prepared using as the base oil a naphthenic lubricating oil of SAE 30 viscosity compounded with a calcium petroleum sulfonate detergent additive and various combinations of a corrosion inhibitor, sulfurized spenm oil, P S -treated terpenes, and zinc dialkyl dithiophosphate. The later was prepared from a mixture of 35 percent of mixed primary amyl alcohols and 65 percent of isobutyl alcohol reacted with P 8 and neutralized with zinc oxide. The calcium petroleum sulfonate detergent was a c-oncentrate consisting of 70 volume percent of mineral lubricating oil diluent and 30 volume percent of calcium salts of petroleum sulfonic acids of about 400 average molecular weight. Thus when using 6 weight percent of the concentrate, roughly 2 Weight percent of actual sulfonate was incorporated int-o the composition.

The corrosion inhibitor was a material known as 'Emulso gen A, which was an ethoxylated fatty acid product of 600 maximum molecular weihgt containing 4 to 5 ethoxy groups per molecule. The sulfurized terpene contained 40 weight percent of sulfur and the sulfurized sperm oil had a sulfur content of 12 Weight percent. The phosphosulfurized terpene was a product of The Lubrizol Corporation and contained 13 weight percent sulfiur. Each of the compositions was mixed with a regular grade of gasoline in the proportion of 1 part of compounded oil and 100 parts of gasoline. The gasoline contained about 1.12 ml. of tetraethyl lead per gallon of gasoline (0.3 gram lead per liter). Some of the compositions were subjected to a 50-hour full load test in an 110 single cylinder, 125 cc., two-stroke engine. The make-up of the compositions and the results of these tests are given in Table I.

TABLE I.50-HOUR ILO ENGINE TESTS 1:100

OIL-TO-FUEL RATIO Composition Ingredients, wt. percent:

' Detergent Concentrate" 6.0 6 0 6. 0 Corrosion Inhibiton..- 0. 0. 5 P2S5-T1eat8d Terpene- 1.

Sulfurized Sperm Oil.

Sulfurized Terpene Base Oil Engine Ratings:

Piston Rings Free Free Slightly seized Exhaust Port Incrustation, Pcrcent. 5 5 Overall Merit Rating (Basis 5. 9 6. 1 5. 6

The overall merit rating reported in Table I was o tained by observing piston cleanliness, coke formation in the ring zone, deposits on the piston head, and exhaust port plugging, assessing each part quantitatively on a merit rating system in which a numerical value of 10 represents a perfectly clean part and zero represents a part covered with the maximum possible quantity of deposits, and averaging the several merit ratings to give an overall merit rating.

The results given in Table I compare tfavorably with those obtained in the same test when using a commercially available 2-st-roke engine oil at an oil-to-fuel ratio of 1 to 25 (rings free; exhaust port incrustation 5%; overall merit rating 5.7). it was not possible to conduct a comparative test at an oil-to-fuel ratio of 1 to with the conventional :oil because of piston seizure after a very short running time.

Example 2 Other of the compositions described in Example 1 were subjected to 60-hour tests in the Saab three-cylinder, 900 cc. two-stroke engine, having a rating of 38 H.P. at 4,250 r.p.m. The test conditions involved an initial I O-minute idle at 1,000 r.p.m., "followed by generally alternating 60 and 10-minute periods at full and partial loads at speeds ranging for the most part fr-om 3,000 to 5,500 r.p.m. The same test conditions were used in each test. The composit-ions tested and the results obtained are given in Table II. The same system of rating was used as in the test of Example 1. The test results compared favorably with those obtained when using a commercially available Z-strokeengine oil at an oil-to-fuel ratio of 1 to 33 in accordance with the recommendation of the engine manufacturer (rings free; exhaust port incrustation 5 overall merit rating 5.1).

TABLE II.60HOUR SAAB ENGINE TESTS OILTO-FUEL RATIO 1:100

Example 3 Composition E iot Example 2 was tested in a 40 horsepower Johnson outboard motor for 50 hours in a cyclic test involving 55-minute periods under full load at- 4,500i200 rpm. and S-minute periods of idle at 600-- 800 r.p.m. An overall merit rating of 4.7 was obtained as compared with a rating of 5.0 with a conventional 2-cycle oil at an oil-to-fuel ratio of 1 to 25.

The examples herein presented are merely illustrative of the invention. There is no intent to limit the scope of the invention thereto, nor is the invention to be limited by any theory regarding its mode of operation. Variations Within the purview of the appended claims are contemplated. I

What is claimed is:

1. A combined lubricant and fuel composition for the lubrication of a two-stroke-cycle gasoline engine which comprises a gasoline to which have been added, per 100 parts of gasoline: Y

(a) from about 0.001 to about part of an alkaline from 5 to 40 percent suliur, unsaturated hydrocarbons that have been phosphosulfiurized with from 5 to Weight percent of a sulfide of phosphorus, and surfunized u-ns aturated hydrocarbons having from 5 to weight percent of sulfur, and (c) from about 0.5 to about 1 part of a higly refined petroleum lubricating oil having a viscosity in the range of 'from to SSU at 210 F., the percentage ratio of said sulf-onate to said lubricating oil in said composition being in the range of about 0.2 to 3 weight percent, and the percentage ratio of said additional sulfur to said lubricating oil in said composition being in the range of about 0.01 to 2 weight percent.

2. Composition 'as defined by claim 1 wherein said sulfu-rcontaining compound comprises a phosphosulfurized terpene.

3. Composition as defined by claim 1 wherein said alkaline earth metal salt is a salt of :a petroleum sulfionic acid of molecular weight within the range of 300 to 700.

4. Composition as defined by claim 1 wherein said suliur cont-aining compound comprises sulfurized sperm oil.

5. Composition as defined by claim 1 wherein said sul'finrcontaining compound comprises :a sulfurized terpene.

6. Composition as defined by claim 1 wherein said sulfiur-containing compound comprises a phosphosulfurized polymer obtained by reaction of polyisobutylene With P285.

7. Composit on as defined by claim 1 including from 0.1 to 1 weight percent of a corrosion inhibitor selected from the class consisting of ethoxylated fatty acids and ethoxylated fatty alcohols of 12 to 18 ca-nbo-n atoms.

8. Composition as defined by claim 1 which additionally contains, per parts of fuel, from about 0.0005 to about 0.05 part of a zinc dialkyl dithiophosphate derived from aliphatic alcohols having in the range of from 3 to 16 carbon atoms.

9. Composition as defined by claim 8 wherein said zinc dialkyl dithiophosphate is derived from a mixture of C and C alcohols.

References Cited by the Examiner UNITED STATES PATENTS 2,291,442 7/1942 Bass et a1 44-58 2,316,078 4/1943 Loane et al. 25246.6 2,369,632 2/1945 Cook et al. 252-466 X 2,807,526 9/1957 Foreman 44-5 8 X 3,000,822 9/ 1961 Higgins et al. 252-327 FOREIGN PATENTS 1,031,916 6/ 1958 Germany. 1,138,584 10/1962 Germany.

597,338 l/ 1948 Great Britain.

888,325 1/1962 Great Britain.

DANIEL E. WYMAN, Primary Examiner.

P. P. GARVIN, Assistant Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2291442 *Nov 22, 1938Jul 28, 1942Lubri Zol CorpUpper cylinder lubricant
US2316078 *Mar 24, 1941Apr 6, 1943Standard Oil CoLubricant
US2369632 *Nov 13, 1941Feb 13, 1945American Cyanamid CoLubricating oils
US2807526 *Oct 4, 1950Sep 24, 1957Standard Oil CoAdditive for motor fuels and fuel compositions containing the same
US3000822 *Jan 22, 1957Sep 19, 1961Lubrizol CorpPhosphorodithioate inhibitors
DE1031916B *Jul 14, 1952Jun 12, 1958Exxon Research Engineering CoVerfahren zur Herstellung von Zusatzstoffen fuer Mineraloele, z. B. Schmieroele
DE1138584B *Feb 25, 1960Oct 25, 1962Exxon Research Engineering CoTreibstoff-Schmieroelgemisch fuer Zweitakt-Vergasermotoren
GB597338A * Title not available
GB888325A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3909425 *Jul 1, 1974Sep 30, 1975Texaco IncLubricating oil composition
US4099915 *Jul 13, 1977Jul 11, 1978Texaco Inc.Method for retarding the evaporation of water
US4147658 *Mar 24, 1978Apr 3, 1979Texaco Inc.Composition for retarding the evaporation of water
US4282106 *Oct 5, 1979Aug 4, 1981Standard Oil Company (Indiana)Low viscosity oils
US5028345 *Jan 31, 1989Jul 2, 1991Ethyl Petroleum Additives, Inc.Lubricating oil composition
US5322631 *Oct 29, 1993Jun 21, 1994Yushiro Chemical Industry Co., Ltd.Water-soluble lubricant composition
Classifications
U.S. Classification44/304, 508/358, 44/305, 44/410, 508/336, 44/366
International ClassificationC10L1/16, C10M135/02, C10L1/14, C10L1/24, C10L1/26, C10M159/12
Cooperative ClassificationC10M2219/022, C10L1/1616, C10M2219/024, C10L1/2493, C10M2207/027, C10M159/123, C10M2209/104, C10L1/14, C10N2240/105, C10M135/02, C10L1/2437, C10M2225/04, C10M2219/044, C10L1/2691, C10M2207/124, C10N2210/02, C10M2223/045, C10M2223/12
European ClassificationC10M135/02, C10L1/14, C10M159/12B