Fuel and related compositions – Liquid fuels – Heterocyclic carbon compound containing a hetero ring having...
Patent
1994-02-28
1995-10-24
Howard, Jacqueline V.
Fuel and related compositions
Liquid fuels
Heterocyclic carbon compound containing a hetero ring having...
44342, 44353, 44329, 44459, 585 10, 585 14, C10L 122
Patent
active
054606330
DESCRIPTION:
BRIEF SUMMARY
This invention relates to the use of additives in fuel oils to reduce emissions on combustion of the fuel oil and to increase engine power when used in an internal combustion engine.
Although modern internal combustion engines are highly efficient and give almost complete combustion of the hydrocarbon fuel used, the slight reduction from total efficiency leads to the formation of black smoke, a proportion of which is particulate carbon and other products of incomplete combustion. Apart from the smoke being unpleasant to breathe and unsightly, the carbon particles may have absorbed in them polynuclear hydrocarbons, which also result from incomplete combustion, some of which are known carcinogens.
Furthermore, internal combustion engines give rise to gaseous emissions on combustion of fuel therein, examples of such emissions being one or more hydrocarbons, carbon monoxide, and oxides of nitrogen and which examples are noxious and undesirable.
This invention provides an additive for reducing one or more particulate and gaseous emissions, which additive is itself metal-free, the additive being a defined polymer of a C.sub.2 to C.sub.6 mono-olefin.
The use of polyolefins in middle distillate fuel oils has been described in the art. For example, GB-A-2 174 102 describes a diesel fuel composition containing a hydrocarbon diesel fuel, a polyolefin and a polyamine for keeping clean the injection system of diesel engines. Injector nozzle fouling is normally accompanied by an increase in particulate emissions.
Further, WO-A-8 600 333 describes a fuel comprising a gasoline, diesel fuel or heavy fuel oil and 0.3 to 0.8 wt % of a liquid poly-C.sub.3 -C.sub.6 -olefin, the fuel reducing the fuel consumption of a diesel engine.
Further, EP-A-376 563 describes a fuel additive, e.g. for diesel fuel, comprising a Mannich base and a polyalkylene, the additive having the effect of reducing intake-valve deposits.
The present invention is based on the observation that certain polymers of mono-olefins, when incorporated in a diesel, heating or jet fuel, reduce the emission of particulates even in the absence of injector deposits.
In a first aspect, the invention provides the use of an additive in a middle distillate fuel oil to reduce particulate emissions on combustion of the fuel oil other than the reduction resulting from a reduction in injector fueling in a diesel engine, of a polymer of a C.sub.2 to C.sub.6 mono-olefin, the polymer having a number average molecular weight of 350 to 1500. Reduction in fouling includes both the removal of existing injector nozzle deposits and the inhibition of deposit formation. The reduction in particulate emission achieved by the present invention may result directly on combustion of a fuel containing the polymer, compared with the emissions resulting from combustion, in the same combustion chamber with the same conditions upstream of the combustion chamber, of fuel not containing the polymer but otherwise identical. The reduction achieved by the first aspect of the invention is herein referred to as the "direct" reduction.
While the applicants do not wish to be bound by any theory, it is believed that under given conditions (which include any deposits present in injectors or elsewhere upstream of the combustion chamber) the presence of the polymer in the fuel, or in the fuel/air mixture, in the combustion chamber results in an improvement in the quality of combustion, as measured by completeness of oxidation. This improvement may in turn be the result of a change in the physical properties of the fuel, or the fuel/air mixture, e.g. the surface tension of the fuel, resulting in improved mixing and reduced soot and smoke formation. The reference above to the presence of the polymer includes the presence of a reaction product of the polymer with a component of the fuel, the reaction having taken place either before entry into the combustion chamber or within the combustion chamber prior to combustion.
In a second aspect, the invention provides the use of an additive in a middle distillate fuel
REFERENCES:
patent: 3838990 (1974-10-01), Mieville
patent: 3846093 (1974-11-01), Feldman
patent: 4175926 (1979-11-01), Wisotsky
patent: 4211534 (1980-07-01), Feldman
patent: 4678479 (1987-07-01), Holmes et al.
patent: 5114435 (1992-05-01), Abramo et al.
Hart Richard J.
Sexton Michael D.
Smith Anthony K.
Exxon Chemical Patents Inc.
Howard Jacqueline V.
Mahon John J.
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