US3019094A

US3019094A - Fuel compositions

Info

Publication number: US3019094A
Authority: US
Publication date: 1962-01-30
Anticipated expiration: 1979-01-30

Description

3,019,094 FUEL COMPOSITIONS Joseph Ray Bondreaux, Lake Jackson, and Fred Stephenson McDonald, Freeport, Tex., assignors to The Dow Chemical Company, Midland, Mich, a corporation of Delaware No Drawing. Filed Feb. 14, 1957, Ser. No. 640,074

7 Claims. (CI. 44-56) This invention relates to a fuel composition for sparkignition internal combustion engines, and more particularly, to a fuel composition containing an additive to improve the performance characteristics of the fuel and a method for decreasing the octane requirement increase in an engine.

In recent years the manufacturers of automotive engines have steadily increased the compression ratios of the engines to increase the horsepower. This trend presents a serious problem to the petroleum industry in that the steady increase in compression ratios necessitates the production of a gasoline with higher octane rating for satisfactory anti-knock performance. To meet the demands of the high compression engines etforts have been directed primarily to the development of motor fuels with higher octane values. This has been largely accomplished by subjecting the gasoline type fuels to severe alkylation and by the addition of additives such as tetraethyl lead to raise the octane value of the fuel. It is known that in the operation of an internal combustion engine deposits are formed in the combustion chamber of the engine and that the engine which has been used requires a fuel of higher octane rating than a new or clean engine in order not to knock. As a new or clean engine is used, the octane requirement of the engine increases with conitnued use until a point is reached where further use will not increase the octane requirement. Apparently, the deposits do not increase above a certain point or, if they do, the additional deposits do not atfect the octane requirement characteristics of the engine. When this leveling off point is reached, the used or dirty engine may have an octane requirement of 10 or more numbers higher than a new or clean engine. Thus, a fuel additive which would improve the performance characteristics of the fuel by reducim the octane requirement increase of an engine in which it is used, would enable the manufacturer of a fuel of lower octane number to meet the re quirements of the high compression engines.

It is, therefore, a principal object of this invention to provide a fuel composition containing an additive which would have improved performance characteristics by reducing the octane requirement increase. A further object is to provide a method of reducing the octane re quirement increase of an engine which occurs with the use of the engine.

The above and other objects are accomplished by aciding a small amount of 1,Z-dimethoxy-l-phenylethane to gasoline. Thus, the-re is prepared a new fuel composition which will produce a much smaller octane requirement increase when the engine is operated on this fuel. The addition of a small amount of 1,2-dimethoxy-1-phenylethane does not materially raise the octane rating of the fuel, but when the fuel is used in the engine, it decreases the tendency of the engine to knock due to the increase of octane requirement. =Further pre-ignition and autoignition are substantially reduced. With a fuel containing the additive, the increase in octane requirements is around 4 to 5 octane numbers as compared to 9 or 10 numbers increase without the additive. Since most of the fuel is consumed by engines which have been used and would be considered dirty, the octane rating of the fuel marketed must have sufiicient octane rating for antiknock performance in these engines. Thus by using this additive, a fuel having an octane rating of around 5 octane numbers lower can be marketed and will give the required performance.

The term octane requirement, as used herein, means the minimum octane value of the fuel which will give knock-free performance in the engine and the term octane requirement increase means the increase in the octane requirement of an engine which occurs when a new or clean engine is used and deposits are formed in the combustion chamber thus requiring a fuel of higher octane number to give knock-free performance.

The gasoline in the composition may or may not contain other additives. Gasolines used today for spark ignition internal combustion engines commonly contain a lead alkyl anti-knock compound, such as tetraethyl lead, as an additive to raise the octane rating of the fuel. Gasolines may also contain additional additives, such as volatile alkyl halides which are added to reduce the deposition of the combustion products of the anti-knock componds added, anti-oxidants, a dye, and other additives. While the addition of 1,2-dimethoxy-l-phenylethane in gasolines which may or may not contain other additives is effective in reducing the octane requirement increase of these fuels, it is especially effective in leaded gasolines. The octane requirement increase is much greater when an engine is operated with leaded gasoline or gasoline containing tetraethyl lead than with unleaded gasolines. Thus the improvement obtained is much greater when the additive is used in this gasoline.

Only a small amount of 1,2-dirnethoxy-1-phenylethane is necessary to effectively reduce the octane requirement increase of an engine. The lower limit of the additive used is generally around 1 milliliter per gallon of fuel, although smaller amounts may be used to obtain significant improvement in lowering the octane requirement increase. Amounts up to 20 milliliters per gallon may be used, but it is preferred to use from 2 to 8 milliliters per gallon. Concentrations over 20 milliliters per gallon, while not deleterious, are uneconomical. The additive is soluble in the gasoline and the new fuel composition can thus be easily prepared by mixing the desired amount of the additive in the gasoline.

In the examples below, 1955 Oldsmobile production models, 8 cylinder, V-8 internal combustion engines were employed. These engines had an 8.5 to 1 compression ratio with 324.3 cubic inch displacement, a maximum horsepower of 202 at 4000 rpm, and a torque rating of 332 pounds per foot at 2400 rpm. The spark advance was l0.5 at 1200 r.p.m. and 22 at 2200 rpm. Prior to each test, the engines were completely dismantled and thoroughly cleaned and all parts critically inspected. All parts that did not meet the measurements, tolerances, clearances, etc. specified by the Oldsmobile Service Manual were replaced. Each run was begun with a new set of spark plugs. The octane requirement for each of the engines was determined before the test and the data obtained in the runs were corrected to a base octane requirement of 80.

The control fuel was octane premium gasoline. This gasoline had an A.P.I. gravity of 59.45, a boiling range of 97 to 415 F., and contained from 2 to 2.4 millimeters of tetraethyl lead per gallon. The test fuel consisted of the control fuel to which was added 1,2-dimethoxy-l-phenylethane as an additive.

Example I Four 100 hour test runs were made where two engines were operated on the control fuel and two engines were operated on the new fuel composition containing the additive.

During the test the octane requirements of the engines were determined after each 20 hours of operation. At

intervals of 20 hours the engines were shut down, the spark plugs carefully removed so as not to disturb any deposits, and a special set of spark plugs, reserved for rating during the particular run, were installed. Primary reference fuels consisting of mixtures of n-heptane and iso-octane of varied octane number were supplied to the carburetor. The lowest octane number employed that did not produce audible knock was taken as a minimum octane requirement. Humidity and barometric pressure differences were corrected according to the standard methods. For every 30 grains of water above the standard humidity of 60 grains per pound of dry air, a correction of one octane number was added to the observed value. The ratio of the barometric pressure to octane requirement is inversed so that for every increase of pressure of 0.3 inch of mercury above the standard barometric pressure of 29.92 inches of mercury, a correction of one octane number was subtracted. After the octane requirement of the engine was determined, the rating plugs were removed and discarded. The original spark plugs were replaced and the engines again operated.

The four runs were made using an SAE W-30 multigrade petroleum base oil containing a polymethacrylate viscosity index improving compound in the engines.

The maximum octane requirement increase obtained in the 100 hour tests with the control fuel was 8.19 for one of the engines and 9.05 for the other. The engines operating on the fuel composition containing 6 milliliters of 1,2-dirnethoxy-1-phenylethane per gallon had an octane requirement increase of 4.11 and 4.79, respectively. Thus, by using the additive in the fuel the octane requirement increase for the engines was reduced by around four octane numbers.

Example 11 Three runs using a fuel containing the new additive and two control runs were performed in the same manner as that described in Example I. In these runs, however, a commercially available SAE 30 motor oil containing detergent, antioxidant, and alkaline reserve additives was used in the engines.

The maximum octane requirement increase obtained in the one hundred hour tests with the control fuel was 8.46 for one of the engines and 10.06 for the other. For

two of the experimental runs, 6 milliliters of 1,2-dimethoxy-l-phenylethane were added per gallon of gasoline. In these two runs, an octane requirement increase of 4.78 and 5.04 were obtained. In the third experimental run, 10 milliliters of the additive per gallon of gasoline were used, and an octane requirement increase of 5.34 octane numbers was realized.

What is claimed is:

1. A fuel composition for spark ignition internal cornbustion engines, which consists substantially of gasoline and a small amount of 1,2-dimethoxy-1-phenylethane sufficient to decrease the octane requirement increase of the fuel.

2. A fuel composition for spark ignition internal combustion engines, which consists substantially of gasoline and from 1 to 20 milliliters of 1,2-dimethoxy-1-phenylethane per gallon.

3. A fuel composition for spark ignition internal combustion engines, which consists substantially of gasoline and from 2 to 8 milliliters of l,2-dimethoxy-1-phenylethane per gallon.

4. The fuel composition of claim 3 wherein the gasoline is leaded gasoline.

5. In the operation of a sprak ignition internal combustion engine, the step to decrease the octane requirement increase, which comprises burning gasoline in the engine to which is added a small amount of 1,2-dimethoxy-l-phenylethane sufficient to decrease the octane requirement increase of the gasoline.

6. In the operation of a spark ignition internal combustion engine, the step to decrease the octane requirement increase, which comprises burning gasoline in the engine to which is added 1,Z-dimethoxy-l-phenylethane in proportions of from 1 to 20 milliliters of 1,2,-dimethoxy-l-phenylethane per gallon.

7. The process according to claim 6, wherein the 1,2- dimethoxy-l-phenylethane is added in proportions of 2 to 8 milliliters per gallon.

References Cited in the file of this patent UNITED STATES PATENTS 1,582,420 Nikaido Apr. 27, 1926 2,143,870 Ellis Jan. 17, 1939 2,768,212 Copenhaver Oct. 23, 1956 2,878,109 Wood et al. Mar. 17, 1959

Claims

1. A FUEL COMPOSITION FOR SPARK IGNITION INTERNAL COMBUSTION ENGINES, WHICH CONSISTS SUBSTANTIALLY OF GASOLINE AND A SMALL AMOUNT OF 1,2-DIMETHOXY-1-PHENYLETHANE SUFFICIENT TO DECREASE THE OCTANE REQUIREMENT INCREASE OF THE FUEL.