Fuel and related compositions – Liquid fuels – Organic nitrogen compound containing
Reexamination Certificate
2000-07-25
2001-11-06
Medley, Margaret (Department: 1714)
Fuel and related compositions
Liquid fuels
Organic nitrogen compound containing
C044S434000
Reexamination Certificate
active
06312480
ABSTRACT:
The present invention relates to solid or pasty additive composition for fuels.
Carburettors and intake systems of gasoline engines as well as injection systems for fuel metering in gasoline and diesel engines are being increasingly contaminated by impurities. The impurities are caused by dust particles from the air sucked in by the engine, uncombusted hydrocarbon residues from the combustion chamber and the crankcase vent gases passed into the carburettor.
These redidues shift the air/fuel ratio during idling and in the lower part-load range so that the mixture is richer and the combustion bustion more incomplete. As a result, the proportion of uncombusted or partially combusted hydrocarbons in the exhaust gas and the gasoline consumption increase.
It is known that fuel additives for keeping valves and carburettor or injection systems clean are used for avoiding these disadvantages (cf. for example: M. Rossenbeck in Katalysatoren, Tenside, Mineralöladditive, Editors J. Falbe and U. Hasserodt, page 223, G. Thieme Verlag, Stuttgart 1978). Depending on the mode of action and preferred place of action of such detergent additives, a distinction is now made between two generations of additives. The first generation of additives was able only to prevent the formation of deposits in the intake system but not to remove existing deposits. On the other hand, additives of the second generator ration prevent and eliminate deposits. They thus exhibit both a keep-clean effect and a clean-up effect. This is permitted in particular by their excellent heat stability in zones of relatively high temperature, in particular in the intake valves.
Such detergents, which may originate from many classes of chemical substances, are generally used in combination with carrier oils and, if required, further additive components, for example corrosion inhibitors and demulsifiers. These liquid additive formulations are added as a rule by means of suitable metering apparatuses to the fuel, where they display their action. However, in the storage and distribution of fuels, there are also cases where no suitable metering facility for liquid fuel additives is available. Here, the existence of fuel additives in solid form which dissolve in fuels would be helpful and advantageous. They would constitute a considerable improvement compared with liquid additives, since the technical complexity and high cost of a metering apparatus would be dispensed with.
DE-A-44 31 409 discloses a pumpable fuel additive paste which can be metered directly into the fuel feed line. The paste has an additive content of from about 5 to 35% by weight and contains from 10 to 60% by weight of oils, fats and/or waxes and from 1 to 10% by weight of a thickener, e.g. bentonite. A disadvantage of such fuel additive formulations is the poor handling properties of the pasty product and the high technical complexity for metering the paste into the fuel.
CA-A-2 143 140 discloses solid additives for internal combustion engines. The solid formulation is prepared by adsorbing a liquid additive onto a porous, solid fuel-soluble carrier, preferably a naphthalene-based carrier, and closing the pores of the carrier after adsorption of the additive. A disadvantage of these solid additives is their inconvenient preparation process. A further serious disadvantage is the limited adsorptivity of the naphthalene pellets used. For example, it is stated that a 1.6 g pellet can typically absorb only an amount of additive which corresponds to one third of its volume.
U.S. Pat. No. 4,639,255 discloses various solid fuel additive composition According to a first embodiment described therein, a pelleted additive formulation which has an additive content of from about 25 to about 75% by weight, based on the weight of the composition, is provided. The additive is contained in a fuel-dis-persible compacting agent, for example paraffin wax, and the additive pellets are sealed on their surface. Examples of preferred additives are hydrogenated polybutenes having a molecular weight of from about 700 to about 1100 and the reaction products of one or more vegetable oils and a polyethyleneimine, additionally derivatized with a sulfonic acid. U.S. Pat. No. 4,639,255 furthermore describes solid fuel additive formulations which contain, as a compacting agent, an aromatic hydrocarbon, for example naphthalene or the readily subliming durene (1,2,4,5-tetramethylbenzene), in an amount of from about 50 to 95% by weight. A further solid additive formulation contains, in addition to a compacting agent, a long-chain alcohol as a modifier for increasing the melting point. Another solid additive formulation has an additive content of from 5 to 40% by weight, the additive pellets having a coating of foamed paraffin wax. Finally, U.S. Pat. No. 4,639,255 describes an additive formulation having a foamed carrier. All of the solid additive formulations described above are still not completely satisfactory with respect to their additive content and/or owing to their relatively complicated preparation. U.S. Pat. No. 4,639,255 expressly points out to persons skilled in the art that the additive content in uncoated formulations may be not more than 40% by weight and should preferably be from about 10 to 30, in particular from about 15 to 25, % by weight.
It is an object of the present invention to provide solid or pasty fuel additive formulations which are distinguished both by a high additive content and by simple preparation. In particular, it is intended to provide highly concentrated, solid or pasty detergent additive formulations.
We have found that this object is achieved, surprisingly, by providing a fuel additive composition which is nonfluid, solid or pasty under standard conditions of temperature and pressure, can be used in particular in gasoline fuels and comprises a preferably homogeneous mixture of a solid compacting agent soluble or dispersible in fuel and at least one liquid fuel additive, the composition having an additive content of from more than 40 to about 99, preferably from about 50 to 95, for example from about 60 to 90, % by weight or from about 75 to 90% by weight, based on its total weight.
The novel additive compositions have the advantage that, owing to their high additive content, they have substantially improved performance. Furthermore, they have the advantage that they can be simply prepared by incorporating the additive or additives into, for example, a melt of the compacting agent which is solid at ambient temperature, homogenizing the mixture, if required allowing it to cool and fabricating it in a suitable manner. It is not necessary either to foam the compacting agent or to subject the solid formulation, for example, processed to give pellets, to surface treatment. The novel formulations also have the advantage that they can be added to fuel without a pump apparatus. Furthermore, the dosage can be more easily adjusted and the viscosity requirements of the additive-containing product are easier to meet.
Statements on the state of aggregation, such as solid, liquid or pasty, are made in the context of the present description with reference to standard conditions of temperature and pressure, i.e. about 20° C. and about 1 atm pressure.
A novel solid or pasty composition has a melting range or a melting point of about 25-95° C., preferably about 30-90° C., in particular about 35-70° C., for example from about 35 to 50° C.
Unless stated otherwise, the additive contents mentioned in the context of the present invention are the sum of the contents of all components for the respective formulation other than the compacting agent.
A homogeneous composition is present if no phase boundaries or separation regions are visually detectable in the novel solid.
In a preferred embodiment, the novel compositions contain at least one detergent additive as the main additive component. In particular, additives which both prevent the formation of deposits in the intake valves and eliminate already formed deposits are used. They thus exhibit both a keep-clean effect and a clean-up eff
Bähr Christoph
Jakob Claus Peter
Posselt Dietmar
Schwahn Harald
BASF - Aktiengesellschaft
Keil & Weinkauf
Medley Margaret
Toomer Cephia D.
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