Abstract: A multi-stage NOx reduction system employs catalysts effective at different temperature ranges and can have reagent injectors associated with each, for use in series or in parallel. A controller directs reagent introduction to one catalyst or the other as temperature and other conditions dictate. Valving can redirect exhaust to particular catalyst zones, if necessary.

Abstract: A low-emissions diesel fuel comprises fungible aviation kerosene grade 55, 50–300 ppm detergent, 25–500 ppm lubricity additive and a bimetallic, fuel soluble platinum and cerium fuel borne catalyst (e.g., 0.1–2.0 ppm platinum COD and 5–20 ppm cerium oleate). The fuel can be used as is or in the form of an emulsion. A method of reducing the emissions of pollutants from a diesel engine, comprising running the engine on a fuel as defined. Retarding engine timing can further reduce NOx and the use of a diesel particulate filter and/or diesel oxidation catalyst can provide further reductions in carbon monoxide, unburned hydrocarbons and particulates.

Abstract: A low-emissions diesel fuel comprises fungible aviation kerosene grade 55, 50-300 ppm detergent, 25-500 ppm lubricity additive and a bimetallic, fuel soluble platinum and cerium fuel borne catalyst (e.g., 0 1-2 0 ppm platinum COD and 5-20 pmm cerium oleate). The fuel can be used as is or in the form of an emulsion A method of reducing the emissions of pollutants from a diesel engine, comprising running the engine on a fuel as defined.

Abstract: A safe, reliable SCR system for reducing NOx emissions from an internal combustion engine hydrolyzes urea or like reagent under sufficient pressure to assure generation of ammonia, without production of solids that could foul injectors or catalysts. The heat for hydrolysis can be provided by the exhaust or an auxiliary means.

Abstract: Gasoline engines equipped with three-way catalysts emit less NOx, hydrocarbons and carbon monoxide when operated on fuels containing a bimetallic catalyst comprising rhodium acetylacetonate and a fuel-soluble platinum compound such as diphenyl cyclooctadiene platinum(II) or platinum acetyl acetonate. The total metals in the additive will be dosed at a concentration of less than about 2 ppm (milligrams of metal to liter of gasoline) based on the amount of gasoline burned in the engine. Preferred dosages will be from about 0.15 to about 1.5 ppm, with a ratio of platinum to rhodium of from about 3:1 to about 15:1.

Abstract: Urea is pyrolyzed in a chamber designed to facilitate gasification of the urea by pyrolysis with conversion of urea to ammonia and isocyanic acid (HNCO) with water vapor and carbon dioxide. The product gases are introduced into exhaust gases from a lean-burn engine, preferably upstream of a turbocharger. The exhaust gases are then contacted with an SCR catalyst.

Abstract: A safe, reliable SCR system for reducing NO.sub.x emissions from a lean-burn internal combustion engine utilizes urea in aqueous solution. A modular assembly is provided for mounting inside a urea reagent tank enables controlled feeding an aqueous urea solution to an injector. The assembly includes a reagent quality sensor, a reagent temperature sensor, a reagent level sensor and a pump.

Abstract: A method improves the operation of a diesel engine through the use of a fuel additive, a diesel particulate trap and a NO.sub.x -reducing catalyst. The operation of the NO.sub.x -reducing catalyst is enhanced by the introduction of urea or like compound upstream of the catalyst at temperatures effective for non-catalytic NO.sub.x reduction and the generation of ammonia. The additive comprises fuel-soluble compositions of platinum group metal in effective amounts to lower the emissions of unburned hydrocarbons and carbon monoxide from the trap. The catalytic activity provided to the exhaust system by the fuel additive is selective and preferably reduces the oxidation of SO.sub.2 to SO.sub.3. The platinum group metal compositions are preferably added in amounts effective to provide concentrations of the metal in the fuel of less than 1 part per million (ppm). Lithium and/or sodium compositions can be used in amounts effective to reduce the trap regeneration temperature, e.g.

Abstract: Operation of a diesel engine with low particulate emissions is achieved. A diesel engine is equipped with a platinum-catalyzed particulate trap. The engine is operated with a blend of diesel fuel and a fuel-soluble cerium composition to reduce the balance point of the trap with reduced cerium content. Preferably, the fuel will also contain a fuel-soluble organo-platinum group metal compound, or an effective platinum group metal compound can be added to the exhaust or combustion air.

Abstract: Emissions of pollutants from diesel engines are reduced by a combination of mechanical devices and fuel additives. In one series of embodiments, diesel emissions of NO.sub.x and particulates are reduced, simultaneously with gaseous hydrocarbons and carbon monoxide, by the combined use of exhaust gas recirculation or engine timing modification, with a particulate trap and a platinum group metal catalyst composition. In another embodiment, a multi-metal catalyst composition, comprising a combination of a platinum metal catalyst composition and at least one auxiliary catalyst metal composition, especially cerium or copper, is employed to provide catalyst metal to the exhaust system including a diesel trap to lower the balance point of the particulate trap (the temperature at which the rate of trap loading equals the rate of regeneration) while also lowering the emissions of carbon monoxide and unburned hydrocarbons. Data for platinum, copper and cerium catalysts establishes effective amounts.

Abstract: A safe, reliable SCR system for reducing NO.sub.x emissions from a lean-burn internal combustion engine utilizes urea in aqueous solution. Overheating and hydrolysis of the solution are prevented by maintaining the temperature of the urea solution sufficiently low that it is not permitted sufficient time at elevated temperature to hydrolyze the urea to such an extent that solids precipitate. In a preferred embodiment, an injector system similar to those used for fuel injection provides a constant feed to injectors and a return line. The feed and injection can be controlled to provide sufficient urea for NO.sub.x reduction and sufficient cooling capacity for the feed and injection system to avoid hydrolysis and deposits of hydrolysis products.

Abstract: Urea is pyrolyzed in a chamber designed to facilitate gasification of the urea by pyrolysis with conversion of urea to ammonia and isocyanic acid (HNCO) with water vapor and carbon dioxide. The product gases are introduced into exhaust gases from a lean-burn engine, preferably upstream of a turbocharger. The exhaust gases are then contacted with an SCR catalyst.

Abstract: The effectiveness is prolonged for catalytic oxidizers to reduce emissions of both HC and CO from two-stroke gasoline engines. A compound of a platinum group metal is added to the cylinder of the engine, to make it available as an active oxidation catalyst by combustion of the fuel. Preferably, the platinum group metal compound is added with the lubricating oil, but can be added to the fuel or through a separate injection.

Abstract: Urea or other solid NO.sub.x -reducing reagent is employed in a selective catalytic reduction process on emissions from diesel and lean-burn gasoline engines. The solid reagent is fed to a gas generator that produces a reactant gas by heating. In one embodiment the reactant gas is maintained at elevated temperatures to prevent condensation products from forming. The reactant gas contains ammonia and is fed to the exhaust on an as-needed basis.

Abstract: Diesel and other lean-burn engines emit less NO.sub.x, when the of fuel comprises an emulsion of hydrocarbon fuel and an aqueous solution of a nitrogenous NO.sub.x -reducing reagent which is separated into its two principal portions prior to combustion. The hot exhaust gases produced by burning the fuel contain NO.sub.x, but the NO.sub.x is reduced by introducing the separated aqueous solution of nitrogenous NO.sub.x -reducing reagent into at least a portion of the exhaust gases and directing them to a catalyst for selective catalytic reduction of NO.sub.x. The fuel emulsion preferably comprises a continuous phase comprising diesel fuel and from about 1 to about 20% (most preferably, from about 2 to about 10%) of a discontinuous phase comprising an aqueous solution of nitrogenous NO.sub.x -reducing reagent. It is also preferred to include in the fuel a corrosion inhibitor and biocide, and optionally a lubricity additive and emulsifier.

Abstract: An improved lubricity water and diesel fuel emulsion is presented. The emulsion is used as fuel for diesel engines, and includes a lubricity additive selected from the group consisting of dimer acids, trimer acids, phosphate esters, sulfurized castor oil, and mixtures thereof.

Abstract: The effectiveness is prolonged for catalytic oxidizers to reduce emissions of both HC and CO from two-stroke gasoline engines. A compound of a platinum group metal is added to the cylinder of the engine, to make it available as an active oxidation catalyst by combustion of the fuel. Preferably, the platinum group metal compound is added with the lubricating oil, but can be added to the fuel or through a separate injection.

Abstract: Platinum group metal fuel additives are effective in fuel environments which make the exclusion of water impractical. The fuels additives comprise a platinum group metal compound and a water-functional composition selected from the group consisting of lipophilic emulsifiers, lipophilic organic compounds in which water is miscible and mixtures of these. The additives are preferably effective in fuel compositions having water contents of at least about 0.01% water by weight.

Abstract: The present invention relates to a process for reducing nitrogen oxides emissions from a diesel engine, which comprises preparing an emulsion of water in diesel fuel which contains a catalytically effective amount of catalyst composition and a lubricity additive, and supplying said emulsion to a diesel engine for combusting therein, whereby combustion of the emulsion leads to a reduction in the nitrogen oxides emissions from the diesel engine when compared with combustion of diesel fuel alone.

Abstract: The invention provides a method employing a fuel additive to improve the operation of a pass-through oxidation catalyst over long periods of time with continued catalytic activity and without the undesirable conversion of SO.sub.2 to SO.sub.3. A pass-through catalyst support is continuously, selectively catalyzed by the combustion of a fuel containing a platinum group metal composition which burns to release the catalyst metal in active form. The effectiveness of the process is attributed to improved combustion in the engine by the catalyst and the treatment of the catalytic oxidizer with active catalyst metal released during combustion such that, in the exhaust system, the soluble organic fraction of the particulates and the levels of gaseous unburned hydrocarbons and carbon monoxide are significantly reduced. The catalysts conditioned by the present invention cause minimal conversion of SO.sub.2 to SO.sub.3.