Fuel and related compositions – Liquid fuels – Organic nitrogen compound containing
Reexamination Certificate
2000-06-21
2003-07-08
Medley, Margaret (Department: 1714)
Fuel and related compositions
Liquid fuels
Organic nitrogen compound containing
C044S385000, C044S391000, C044S400000
Reexamination Certificate
active
06589302
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a fuel additive concentrate comprising a fuel additive for improving the lubricity of fuels such as diesel and gasoline, to the fuel additized with the fuel additive concentrate and to a method of operating an internal combustion engine with said fuel. The fuel additive concentrate remains fluid and stable at low temperatures and is therefore suitable for addition to fuels at low temperatures. Fuels containing the fuel additive exhibit improved lubricity and reduced friction which is reflected in enhanced vehicle fuel economy and reduced engine deposits.
2. Background of the Invention
Sulfur compounds are oxidized and discharged into the air as fuels are burned, leading to environmental problems such as “acid rain”. Since untreated diesel fuels contain 1% by weight or more of sulfur, the need to improve air quality has led to the development of fuels with minimized sulfur content. The sulfur content of fuels such as diesel fuel can be reduced by additional refining, e.g., by severely hydrotreating diesel fuel to produce a low sulfur content fuel. It is now considered desirable to reduce the level of sulfur in such fuels to less than 0.2% by weight and, preferably, to less than 0.05% by weight, more preferably less than 0.01% by weight. However, it is generally recognized that these additional refining operations dramatically diminish fuel lubricity. The term “lubricity,” as utilized herein, refers to the ability of the fuel to reduce the friction on and subsequent wear of these moving parts. Fuels act as a primary source of lubrication for moving parts located inside engine systems, e.g., rotary/distributor fuel pumps, fuel ignition systems, and the like. Therefore, a fuel having diminished lubricity will result in increased friction and wear on those moving parts that are primarily lubricated by the fuel alone.
Another attempt at improving the quality of the air is through the implementation of government legislated fuel economy standards. This legislation has led automotive and fuel additive suppliers to undertake efforts to enhance the fuel economy of motor vehicles. It is especially desirable to enhance the fuel economy of vehicles operated on poor lubricity fuels.
One approach to achieving enhanced fuel economy is by improving the efficiency of the engine in which the fuel is used. Improvement in engine efficiency can be achieved through a number of methods, e.g., improved control over fuel/air ratio, decreased crankcase oil viscosity, reduced internal friction at specific, strategic areas of an engine, etc. For example, inside an engine, about 18% of the fuel's heat value, i.e., the amount of heat released in the combustion of the fuel and therefore able to perform work, is dissipated due to internal friction at engine components, e.g., bearings, valve train, pistons, rings, water and oil pumps, etc. Only about 25% of the fuel's heat value is converted to useful work at the crankshaft. Friction occurring at the piston rings and part of the valve train account for over 50% of the heat value loss. A lubricity improving fuel additive capable of reducing friction at these engine components by a third will cause approximately 3% of the fuel's heat value to be transmitted as useful work at the crankshaft, thus improving vehicle fuel economy.
Most fuels are additized by injecting a homogeneous, low viscosity and liquid additive concentrate into the fuels while they are loaded into trucks at terminal racks. Commonly such additives are diluted in an aromatic solvent (e.g., xylene, aromatic 100, heavy aromatic naphtha) to produce a homogeneous, low viscosity fluid concentrate which is suitable for rack injection. Obviously, the additive concentrate must be fluid, homogeneous and low in viscosity under all atmospheric conditions encountered at such outdoor truck loading facilities. Unfortunately, many fuel additive concentrates are unsuitable for additization at low temperature. For example, Tolad 9103 (Baker Hughes, Inc., Pasadena, Tex.), a mixture of polymerized fatty acids and non-polymerized fatty acids dissolved in heavy aromatic naphtha, turns solid at 0° F. within one day.
Therefore, there has been a continual search for fuel additives which improve the lubricity of low sulfur fuels and which remain stable at low temperatures when diluted in aromatic solvents.
SUMMARY OF THE INVENTION
In accordance with the present invention, a fuel additive concentrate for improving the lubricity of fuels containing less than about 0.2 weight percent sulfur is provided, the concentrate comprising a fuel additive composition diluted in an aromatic solvent, said fuel additive composition representing from about 0.5 to about 90 weight percent of the total weight of the concentrate, said fuel additive composition comprising the reaction product of:
(1) a first glyceride possessing an unsaturated fatty acid content of at least about 40 mole %, based on the total weight of fatty acid present in the first glyceride, and an iodine number of greater than 35;
(2) a second glyceride possessing an unsaturated fatty acid content of less than about 20 mole %, based on the total weight of the fatty acids present in the second glyceride, and an iodine number of less than 35; and,
(3) at least one alkanolamine.
Also provided is a fuel composition comprising:
(a) a major amount of fuel containing less than about 0.2 weight percent sulfur; and,
(b) a minor amount of a fuel additive composition comprising the reaction product of:
(1) a first glyceride possessing an unsaturated fatty acid content of at least about 40 mole %, based on the total weight of the fatty acids present in the first glyceride, and an iodine number of greater than 35;
(2) a second glyceride possessing an unsaturated fatty acid content of less than about 20 mole %, based on the total weight of the fatty acids present in the second glyceride, and an iodine number of less than 35; and,
(3) at least one alkanolamine.
Also provided is a method of operating an internal combustion engine comprising operating the engine with a fuel composition comprising:
(a) a major amount of a fuel containing less than about 0.2 weight percent sulfur; and,
(b) a minor amount of a fuel additive composition comprising the reaction product of:
(1) a first glyceride possessing an unsaturated fatty acid content of at least about 40 mole %, based on the total weight of the fatty acids present in the first glyceride, and an iodine number of greater than 35;
(2) a second glyceride possessing an unsaturated fatty acid content of less than about 20 mole %, based on the total weight of the fatty acids present in the second synthetic oil, and an iodine number of less than 35; and,
(3) at least one alkanolamine,
It has been unexpectedly observed that the fuel additive of this invention produced from first and second glycerides and alkanolamine exhibits improved low temperature dissolution properties compared to a fuel additive produced from the second glyceride alone and alkanolamine. The unique mixed-glyceride fuel additive composition of this invention achieves this optimization of low temperature dissolution properties while simultaneously enhancing vehicle fuel economy and reducing vehicle engine deposits. While not wishing to be bound by theory, it is believed by the inventors that this unanticipated improvement is the result of the higher unsaturation content present in the fuel additive concentrate of this invention relative to fuel additives produced from the second glyceride alone and alkanolamine.
The term “fuel” as utilized herein shall be understood as referring to hydrocarbon fuel such as gasoline, fuel oils such as diesel fuel, alcoholic fuels such as methanol or ethanol, and mixtures of any of the foregoing.
The term “low sulfur” as applied to the fuel herein shall be understood as referring to the presence of less than about 0.2 wt. % elemental sulfur in the fuel.
The term “diesel” as utilized herein shall be understood as referring to that fraction of crude oil t
Cangelosi Thomas
Cryvoff Serge A.
DeBlase Frank J.
DeRosa Thomas F.
Hayden Thomas E.
Dilworth & Barrese LLP
Medley Margaret
Texaco Inc.
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