US3034875A

US3034875A - Automotive fuel

Info

Publication number: US3034875A
Application number: US602455A
Authority: US
Inventors: John P Buckmann
Original assignee: Union Oil Company of California
Current assignee: Union Oil Company of California
Priority date: 1956-08-06
Filing date: 1956-08-06
Publication date: 1962-05-15
Anticipated expiration: 1979-05-15

Description

United States Patent Ofiice 3,034,875 Patented May 15, 1062 3,034,875 AUTOMOTIVE FUEL John P. Buckmann, Yorba Linda, Calif, assignor to Union Oil (Iompany of California, Los Angeles, Calif, a corporation of California No Drawing. Filed Aug. 6, 1956, Ser. No. 602,455 4 Claims. (Cl. 44-58) This invention relates to automotive fuels suitable for V (use in modern high compression automotive engines. More particularly it relates to gasolines which produce a smaller octane requirement increase (R1) when used in automotive engines than ordinary gasolines.

It is well known that a clean engine, i.e. one from which deposits within the combustion chambers have been removed, has a lower octane requirement than does an engine which has been operated until the amount of deposits within the combustion chambers has reached equilibrium such as is or may be obtained by operating the engine with a given fuel for the equivalent of 3000 to 5000 or more road miles.

By the term octane requirement of an engine is meant the octane number or rating of a fuel which just prevents knocking (audible knock uponacceleration) of the engine. By the term octane requirement increase or 0R1 of an engine is meant the'difference in octane requirement of an engine containing combustion chamber deposits as compared with the same engine from which combustion chamber deposits have been removed. Although the ORI refers to the increase in octane requirement of an engine the term will be applied to a fuel herein in the following sense. A gasoline or fuel which causes large ORI values in an engine will be referred to as one having a high ORI. Conversely a fuel which causes only small ORI values in an engine will be referred to as one having a low ORI. Furthermore additives described herein are said to reduce the 0R1 characteristics of the fuel, meaning that the fuel containing the additives will, on use in an engine, cause less octane requirement increase in the engine than will the base fuel without such additives.

It is known that starting with a clean engine the octane requirement of the engine increases as combustion chamber deposits build up in the engine and continues to increase until an equilibrium amount of deposits are formed. Other factors influencing the octane requirement include the condition of carburetor and ignition system including breaker points, spark plugs, etc.

With commercial automotive fuels, e.g., gasolines of various grades available on the market it is found that the ORI of automotive engines will generally be in the order of 6 to 9 or more octane numbers. Such increases in octane requirements are highly objectionable as is well known since the higher the octane requirement the higher the cost of fuel necessary to operate the engine efilciently.

It is an object of this invention to provide an automotive gasoline containing additive materials which impart to the gasoline lowered ORI characteristics.

It is another object of this invention to provide a gasoline suitable for use in modern high compression automotive internal combustion engines which gasoline does not increase the octane requirement of an engine to'an objectionable degree, and at least the use of which does not cause an ORI in the engine which is as great as that caused by the use of fuels without such ORI additive.

A particular object of this invention is to provide a gasoline suitable for use in present day high compression internal combustion automotive engines which contains anti-knock agents such as tetraethyl lead (T.E.L.), antioxidants and/or gum inhibitors and to which is added small amounts of an agent or agents which reduce the OR I characteristics of the gasoline.

It has been found that by adding very small amounts of lecithin with or without small amounts of a paraflinic type mineral lubricating oil to automotive gasolines, engines operating on the resulting fuels show an ORI substantially less than the corresponding ORI observed with gasolines which do not contain these additives.

The lecithin may be a purified lecithin but preferably is a commercial lecithin such as one obtained from soya bean oil and referred to as a plastic lecithin which contains approximately 65% of lecithin in soya oil. Also available commercially is a liquid lecithin product containing about 60% of lecithin in soya bean oil and this product may be employed as the lecithin portion of the additive combination. Under any circumstance, the lecithin itself appears to be the active agent and the fatty oil with which it is associated in the various commercial products does not appear to have deleterious effects, at least in the amounts in which it is present. Moreover, it is to be noted that the material referred to herein as lecithin comprises a mixture of acetone-insoluble phospha- {tides and it is on the basis of acetone solubility that the percentage of lecithin in the commercial products is determined.

The amount of lecithin to be employed to impart the desired low ORl characteristics to a gasoline will be less than 0.002% and preferably less than 0.0015% by weight based on the gasoline. At the lower concentrations amounts as low as 0.0001% are found to be effective and presumably amounts less than 0.000l% will be effective in reducing ORI. A particularly preferred range will be between 0.0002% and 0.001% by weight based on the finished fuel. I

These amounts are based upon commercial lecithin containing approximately 65% lecithin corresponding amounts of pure lecithin, as described above, would be less than about 0.00 l3% and preferably less than 0.00098% with amounts as low as about 0.000065% being effective. The particularly preferred range being between 0.000l3% and .00065% In the following discussion and in the claims unless otherwise noted the term lecithin will be used to describe and will particularly refer to the commercial 65% lecithin.

The above amounts of lecithin used alone or in combination with paraffinic mineral oil as described below are found to reduce ORI characteristics of gasolines to which they are added. The efiect is not limited to one type of gasoline but is observed in substanitally any high octane gasoline whether or not it contains anti-knock agents and/ or gum inhibitors, or the like.

The second additive material which appears to cooperate with lecithin to give the desired lower ORI in fuels containing the additive is a paraffinic mineral lubricating oil of about medium grade. The oil may be an untreated distillate oil providing it is of relatively low wax content or it may be a dewaxed distillate oil. Preferably the oil is a dewaxed, solvent-treated paraifinic type distillate oil of about medium to light lubricating oil grade. The fol- TABLE I Characteristics of Hydrocarbon Oils Suitable for Use With Lecithin in Gasoline Over-all Preferred Ideal Range Range Gravity. A.P.I. at 60 F 34. -26. 0 32.0-26.5 28.6 Viscosity, SSU at 100 F 150-1, 00 250-500 318 Viscosity, SSU at 210 F 2. 3-77. 45 75 52.2 Viscosity Index Above 60 above 80 85 Viscosity-gravity Constant 0. 790-0. 825 0. 8000 820 0.817 Flash point, COG, F 410-500 425-475 445 Pour Point, F 20 20 5 Distillation, F.:

Initial 660-750 680-725 700 690 8l5 720-790 760 720 865 760-850 815 7 65'970 800 -930 892 95-99 98-99 99 a Values calculated to atmospheric pressure from vacuum distillation data. Distillation made at l to 5 mm. Hg pressure.

Methods of dewaxing and solvent treating lubricating oil fractions are well known and need not be described herein except to point out that the dewaxing, which may be effected by substantially any method, with or without the aid of a dewaxing solvent, should produce a finished oil having a pour point not higher than about 20 F. Moreover, the solvent treatment may be carried out using any of the well known selective solvents which remove the more aromatic fractions leaving the more paraffinic fractions. Suitable oils are obtained from Waxy or parafiinic Western crude oils, from Mid-Continent type oils or from Eastern or Pennsylvania type crude oils.

It is essential that the lubricating oil have a viscosity between about 42 and 78 SSU at 210 F. and a flash point of at least about 400 F. since lighter oils do not appear to have the characteristics required.

Just what effect the mineral oil has in combination with lecithin is not entirely understood although it is believed that possibly its primary elfect is to prevent deposition of the lecithin in the induction system of the engine. It is thus believed to be a carrier for the lecithin and insures that all of the lecithin present in the fuel is carried into the combustion chamber. It is possible also that the lubricating oil may in some way cooperate with the lecithin in reducing ORI.

When mineral oil is used, the amount will be less than about 0.01% and preferably less than about 0.0075% based on the finished gasoline. Any amounts less than these appear to have some effect and serve the purposes described. Generally, when such oil is added it will be in amounts approximately equal to or greater than the amounts of lecithin up to 10 to times the amount of lecithin employed so long as the amount remains below the upper limit indicated. Generally between about 0.0001 and 0.01% will be employed.

Gasolines or automotive fuels to which the lecithin or lecithin and oil may be added to produce the lowered ORI effect include substantially all grades of gasoline presently being employed in automotive and internal tained by thermal and/or catalytic cracking methods. In such case, the gasolines will contain gum inhibitors and may or may not contain T.E.L. Generally automotive and aircraft gasolines contain both straight-run and cracked stocks with or without alkylated hydrocarbons, reformed hydrocarbons and the like. The preparation of straight-run, alkylated, reformed and cracked stocks for blending in the preparation of automotive gasolines, aircraft gasolines, and the like, are well known and need not be further described. Gasolines suitable for use in present day automotive engines with which this invention is primarily concerned will generally have the characteristics shown in Table II and it is primarily to gasolines of the character indicated to which the additive of this invention is added and found to be effective.

* Determined by ASIM method D-381. b AS'IM method D-86.

The above data were obtained on two commercial gasolines of the grades indicated and are believed to be typical of commercial gasolines marketed at the present time. These gasolines contain 2-3 ml. of tetraethyl lead per gallon and 5 to 15 pounds of a phenolic type gum inhibitor per 1000 gallons. It is to be pointed out that the usefulness of the additive of this invention is not limited to gasolines of the types indicated as would be understood in the art. The same additive is effective in gasolines of lower or higher volatility as well as gasolines having lower or higher knock rating, many of which gasolines are presently commercially available. Gasolines which contain gum inhibitors may contain single materials or combinations of such inhibitors. The use of gum inhibitors is well known in the art and need not be further described. It might be pointed out that the inhibitors are generally aromatic compounds containing amino and/or hydroxyl groups and it should be mentioned further that the particular gum inhibitor or inhibitors employed does not appear to have any appreciable efiect on the ability of the described additive combination to perform the functions described herein.

Since both the lecithin and the hydrocarbon oil employed are readily soluble on gasoline no difficulty is encountered in preparing the improved fuels of this invention. Lecithin may be sepaartely added to and dissolved in the fuel or if oil and lecithin are to be added they may first be combined, the lecithin being dissolved in the oil and the resulting solution added to the gasoline. Moreover, the separate materials or the oil solution of lecithin may be dissolved in a small portion of the gasoline or in a small amount of one of the stocks used in preparing the finished gasoline and the resulting concentrate used in preparing the finished gasoline. Preferably the additive or additives will be added and mixed into the gasoline during the blending operations or at the time of incorporating lead and/ or gum inhibitor in the gasoline or gasoline stocks. It is to be noted that the lecithin at least must not be added to the stocks or gasoline prior to a sweetening treatment in which caustic or the like is employed.

Tests to determine the ORI characteristics of gasolines with and without the lecithin and lecithin and mineral oil additives of this invention have been run in standard 1952 and 1955 Oldsmobile S-cylinder engines equipped with 4 barrel carburetors. In these tests a clean engine is run with the fuel to be tested for a period of 160 hours using a cyclic operation involving alternate periods of high and low speeds which will be described more fully in connection with each engine. At the end of this period the carburetor is replaced with a test carburetor which is maintained in perfect operating condition and by using reference fuels of known octane rating the octane requirement of the dirty engine is determined. At this time the cylinder head is removed and all combustion chamber deposits are removed. The cylinder head is replaced, and using the test carburetor the octane requirement of the engine is again determined. The difference between the octane requirement of the dirty engine and the clean engine is the ORI produced by the gasoline under test. It is often referred to as the ORI of the gasoline.

In these tests the 1952 engine is operated for a total of 160 hours, equivalent to a road mileage of 6,400 miles. In this case the engine is operated for 36 seconds at 2000 r.p.m., a load of 46 pounds and at a brake horsepower of 23 and then for 24 seconds at 1100 r.p.m. a load of 15 pounds and at a brake horsepower of 4. This cycle is repeated during the entire run.

The 1955 engine is operated for 160 hours, equivalent to a road mileage of 7680 miles. In this case the engine is operated for 27 seconds at 2000 rpm, a load of 46 pounds and a brake horsepower of 23 and then for 33 seconds at 1100 r.p.m. with no load and a brake horsepower of 0. This cycle is repeated throughout the test. In the case of both engines and throughout the tests, cooling water is controlled so as to maintain an outlet temperature of 165 F .i-5 F. with an inlet temperature of F. to F. below the outlet temperature and oil temperatures are maintained at 175 F15 F. An S.A.E. 1030 grade solvent treated paraflinic mineral oil for A.P.I. services MS, MM, ML, and DG is used in the crankcase and is changed after 60 and 120 hours of operation. Makeup oil is added each 8 hours as required to maintain the correct oil level in the engine.

The results of tests on the following gasolines with and without lecithin and lecithin and oil are as follows:

c Diflerence between ORI of base tueland base fu el plus additives.

b A premium gasoline of 95 octane rating containing straight-run and catalytically cracked hydrocarbon base stocks, 3 of lead per gallon and .005% by weight of a phenolic type gum inhibitor. This fuel has characteristgs silmilar to those shown in Table II in the column headed remium aso ines.

E; A dewaxed, solvent extracted Western parafiinlc mineral oil having the characteristics set forth in Table I, last column.

TABLE IV 0R1 Tests m 1952 Oldsmobile Engine Fuel Octane Requirement Additive ORI Effect 1 No. Composition Dirty Clean 1 Basefuel 84.8 75.8 9.0 2 Fuel No. 1 Plus 0.0007% 82.6 77.7 4.9 4.1

lecithin. 3 Fuel N0. 1 Plus 0.001% 82.4 78.7 3.7 5.3

lecithin and 0.01% oil. 4 Fuel No. 1 Plus 0.0005% 81.1 77.0 4.1 4.9

lecithin and 0.005% oil. 5 Fuel No. 1 Plus 0.0013% 84.6 78.6 6.0 3.1

lecithin and 0.009% oil. 6 Base Fuel 83.0 75.0 8.0 7 Fuel No. 6 Plus 0.0007% 81.5 76.9 4.6 3.3

, lecithin. 8 Fuel No. 6 Plus 001% 80.9 76.0 4.9 3.1

lecithin and 0.005% oil.

a Difference between ORI of base fuel and base fuel plus additives b A premium gasoline of octane rating containing straight-run and catalytically cracked hydrocarbon base stocks, 3 ml. of lead per gallon and 005% by weight of a phenolic type gum inhibitor. This fuel has characteristics similar to those shown in Table II in the column headed Premium Gasolines.

A dcwaxed,solvent extracted, western paratnnic mineral oil having the characteristics set forth in Table I, last column.

d A regular grade gasoline having an octane rating of 84 and containing cracked and straight-run base stocks, 2 ml. of lead per gallon and .0035% by weight of a phenolic type gum inhibitor. This gasoline has characteristics similar to those shown in Table II in the column headed Begular Gasolines."

Although the above-described engine tests were made with a gasoline containing tetraethyl lead and gum inhibitor, the advantageous ORI effects of the lecithin and lecithin plus paraiiinic hydrocarbon oil are observed as well in gasolines which do not contain tetraethyl lead and/or gum inhibitors. Engine tests on gasolines which dot not contain lead and/or gum inhibitor substantiate this position. The amount of lead which may be employed in preparing gasolines to which the additives of this invention may be added may thus vary from 0 to as high as about 5 ml. of tetraethyl lead per gallon. Generally, automotive gasolines will contain 1 to 3 m1. of T.E.L. per gallon and aviation fuels may contain as high as 4.5 or 5 ml. per gallon.

Gum inhibitors which may be employed in amounts generally ranging from about 5 pounds to about 25 pounds per 1000 barrels of gasoline include substantially any of the gum inhibitors which are now universally employed in the preparation of automotive and aviation gasolines. The particularly preferred gum inhibitors are aromatic ring compounds having aliphatic and hydroxyl substituents. Ditertiarybutyl paracresol has been found to be very satisfactory. In view of the fact that gasoline inhibitors are well known in the art and are universally employed in todays gasolines, a further description of these materials is considered to be unnecessary.

The above description and examples of our invention are illustrative of the broader aspects of this invention and are not to be taken as limiting the invention as set forth in the following claims.

I claim:

-1. An internal combustion engine fuel consisting essentially of hydrocarbons boiling in the gasoline boiling range containing less than about 0.002% by weight of lecithin but sufficient to impart reduced ORI characteristics to said fuel, and containing also less than about 0.01% by weight of a paraffinic hydrocarbon oil of medium lubricating oil grade having a viscosity at 210 F. of between about 42 and about 78 S.S.U., a flash point between 410 F. and 500 F., and a viscosity index greater than about 60, but sufficient to prevent deposition of said lecithin in the induction system of an engine operating on said fuel.

2. An internal combustion engine fuel consisting essentially of hydrocarbons boiling in the gasoline boiling range containing less than about 0.002% by weight of lecithin but sufiieient to impart reduced ORI characteristics to said fuel, and containing also between about 0.0001% and about 0.01% by weight of paraffinic hydrocarbon oil of medium lubricating oil grade having a viscosity at 210 F. of between about 42 and about 78 S.S.U., a flash point between 410 F. and 500 F., and a viscosity index greater than about 60, but sufiicient to prevent deposition of said lecithin in the induction systern of an engine operating on said fuel.

3. An internal combustion engine fuel consisting essentially of hydrocarbons boiling in the gaso ine boiling range and containing up to about ml. of tetraethyl lead per gallon, between about 5 and 25 pounds per 1000 barrels of a gum inhibitor to which is added less than 0.002% by weight of lecithin but sufficient to impart reduced ORI characteristics to said fuel, and containing also less than about 0.01% by weight of a parafiinic hydrocarbon oil of medium lubricating oil grade having a viscosity at 210 F. of between about 42 and about 78 S.S.U., a flash point between 410 F. and 500 F., and a viscosity index greater than about 60, but suflicient to prevent deposition of said lecithin in the induction system of an engine operating on said fuel.

4. An internal combustion engine fuel consisting essentially of hydrocarbons boiling in the gasoline boiling 5 range and containing up to about 5 ml. of tetraethyl lead per gallon, between about 5 and pounds per 1000 barrels of a gun inhibitor to which is added less than 0.002% by weight of lecithin but sufiicient to impart reduced ORI characteristics to said fuel, and containing also between about 0.0001% and about 0.01% by weight of a paraffinic hydrocarbon oil of medium lubricating 'oil grade having a viscosity at 210 F. of between about 42 and about 78 S.S.U., a flash point between 410 F. and 500 F., and a viscosity index greater than about 60, but suflicient to prevent deposition of said lecithin in the induction system of an engine operating on said fuel.

References Cited in the file of this patent UNITED STATES PATENTS 2,155,678 Oosterhout Apr. 25, 1939 2,165,651 Rees et al July 11, 1939 2,207,430 Burk et al July 9, 1940 2,208,105 Rathbun July 16, 1940 2,322,007 Fischer June 15, 1943 2,352,760 Bell July 4, 1944 2,365,377 Bell Dec. 19, 1944 2,405,560 Campbell Aug. 1 3, 1946 2,437,041 Proell Mar. 2, 1948 FOREIGN PATENTS 464,055 Great Britain Apr. 12, 1937 733,820 Great Britain July 20, 1955

Claims

1. AN INTERNAL COMBUSTION ENGINE FUEL CONSISTING ESSENTIALLY OF HYDROCARBON BOILING IN THE GASOLINE BOILING RANGE CONTAINING LESS THAN ABOUT 0.002% BY WEIGHT OF LECITHIN BUT SUFFICIENT TO IMPART REDUCED ORI CHARACTERISTICS TO SAID FUEL, AND CONTAINING ALSO LESS THAN ABOUT 0.01% BY WEIGHT OF A PARAFFINIC HYDROCARBON OIL OF MEDIUM LUBRICATING OIL GRADE HAVING A VICOSITY AT 210* F. OF BETWEEN ABOUT 42 AND ABOUT 78 S.S.U., A FLASH POINT BETWEEN 410* F. AND 500* F., AND A VISCOSITY INDEX GREATER THAN ABOUT 60, BUT SUFFICIENT TO PREVENT DIPOSITION OF SAID LECITHIN IN THE INDUCTION SYSTEM OF AN ENGINE OPERATING ON SAID FUEL.