416 results about "Diesel exhaust" patented technology

A filter, system and method is provided for filtering nanoparticles in a hot gas, namely particles <about 1 micron in a gas >about 200° C. and further particularly >about 450° C. including diesel exhaust. The filter includes filter media material composed of fibrous filter media having a plurality of fibers and granular filter media having a plurality of granules extending from the surfaces of the fibers. The filter is characterized by a permeability >about 3×10⁻¹² m² and an inertial resistance coefficient <about 1×10⁶ m⁻¹. The filter captures particles in the Most Penetrating Region (MPR). A filter system includes a nanoparticle filter in series with a diesel exhaust treatment element.

The invention is directed at a mullite-aluminum titanate porous diesel particulate filter constituting a porous ceramic body containing, expressed in terms of weight percent of the total body, of 60-90%, preferably 70-80%, most preferably 70% iron-aluminum titanate solid solution having a stoichiometry of Al2(1-x)Fe2xTiO5, where x is 0-0.1, and 10-40%, preferably 20-30%, most preferably 30% mullite (3Al2O3.2SiO2), and consists essentially, expressed in terms of weigh percent on the oxide basis, of 3 to 15% SiO2, 55 to 65% Al2O3, 22 to 40% TiO2, and 0 to 10% Fe2O3, and being useful for filtration of diesel exhaust. The inventive diesel particulate filter exhibits high interconnected open porosity and large median pore size, in combination with high permeability when fired to a temperature of between 1650° to 1700° C., along with high thermal shock resistance and good filtration capability.

The invention provides low temperature NO₂ trap compositions useful for adsorbing NO₂ from a gas stream at lower temperatures, and releasing the NO₂ at higher temperatures. The low temperature trap compositions are useful for incorporation into a diesel exhaust system equipped with a soot filter. The NO₂ from the diesel exhaust can be stored when the exhaust temperature is cool, e.g., during startup and at times of low load, and released when the exhaust is at higher temperatures. The released NO₂ serves as an effective oxidant for the combustion of soot deposited on the soot filter. These temperatures are significantly lower than those required for the combustion of soot using O₂ as an oxidant. The methods of the invention thereby provide a method for regenerating the soot filter within operating temperature ranges typical of diesel engine exhaust systems.

An aluminum titanate-based ceramic article having a composition comprising u (Al₂O₃—TiO₂)+v (R)+w (3Al₂O₃—2SiO₂)+x (Al₂O₃)+y (SiO₂)+z (1.1SrO-1.5Al₂O₃-13.6SiO₂—TiO₂)+a (Fe₂O₃—TiO₂)+b (MgO-2TiO₂), where, R is SrO—Al₂O₃-2SiO₂ or 11.2SrO-10.9Al₂O₃-24.1SiO₂—TiO₂, where u, v, w, x, y, z, a and b are weight fractions of each component such that (u+v+w+x+y+z+a+b=1), and 0.5<u≦0.95, 0.01<v≦0.5, 0.01<w≦0.5, 0≦x≦0.5, 0≦y≦0.1, 0≦z≦0.5, 0<a≦0.3, and 0≦b≦0.3. A method of forming the ceramic article is provided. The ceramic article is useful in automotive emissions control systems, such as diesel exhaust filtration.

Disclosed are ceramic articles, which in one aspect are composed predominately of a cordierite having a composition close to that of Mg₂Al₄Si₅O₁₈. The ceramic articles possess a microstructure characterized by a unique combination of relatively high porosity and relatively narrow pore size distribution, both as measured by mercury porosimetry, that render the ceramic structure useful for ceramic filter applications requiring high thermal durability and high filtration efficiency coupled with low pressure drop along the length of the filter. Such ceramic bodies are particularly well suited for filtration applications, such as diesel exhaust filters or DPFs. Also disclosed are methods for the manufacture of the ceramic articles described herein.

A coated diesel exhaust filter is provided that applies a relatively low pressure drop across the exhaust system despite the buildup of soot deposits. The filter includes a porous ceramic structure having an inlet end, an outlet end, and a plurality of gas inlet and gas outlet channels disposed between the inlet and outlet ends, the channels being separated by porous ceramic walls. A catalyst is distributed at least partly within the porous ceramic walls of the structure, and is distributed at a higher concentration within portions of the ceramic walls adjacent to the outlet surfaces than within portions of the ceramic walls adjacent the inlet surfaces. Both the inlet and outlet surfaces are substantially free of the catalyst in order to maintain a gas-conducting porosity in these surfaces. The resulting filter effectively treats nitrogen oxides, carbon monoxide and unburned hydrocarbons present in the exhaust gas stream while advantageously imposing a relatively low pressure drop across the exhaust system even when soot deposits accumulate on the inlet surfaces of the ceramic walls.

An oxidation catalyst for the treatment of exhaust gas emissions, such as the oxidation of unburned hydrocarbons (HC), and carbon monoxide (CO) and the reduction of nitrogen oxides (NOx) from a diesel engine and methods of exhaust gas treatment are disclosed. More particularly, a washcoat composition is disclosed comprising at least two washcoat layers, a first washcoat comprising palladium supported on ceria-zirconia and ceria-zirconia-alumina and a second washcoat containing one or more of platinum and palladium and one or more hydrocarbon storage components. An undercoat may also be included in the catalyst. Also disclosed are method of exhaust gas treatment and diesel exhaust gas treatment systems that include the oxidation catalyst and a downstream soot filter.

A diesel exhaust treatment system and method of oxidizing NO to NO2 at low temperatures are provided. The system utilizes a platinum catalyst on a zirconia-stabilized silica support which oxidizes NO in the exhaust gas to NO2 and uses the NO2 in an amount sufficient to oxidize particulate trapped on a particulate filter. The catalyst is preferably pre-treated at a temperature of between about 500 to 650° C. in a NO-oxygen-nitrogen mixture to increase conversion at low temperatures. The catalyst preferably includes an additional oxide component selected from the group consisting of TiO2, P2O5, WO3, B2O3, and Al2O3. or a heteropolyacid component to further increase activity at low temperatures or to decrease platinum loading at the same level of performance.

A system for aftertreatment of diesel engine exhaust on a vehicle which is equipped for dynamic braking, using the electrical power generated by the dynamic braking to energize a resistor bank which incinerates particulate matter which has been collected in a particulate matter filter, thereby regenerating the filter.

A diesel exhaust aftertreatment device regeneration system includes an exhaust conduit adapted to conduct exhaust gas to an exhaust gas aftertreatment device. The system further includes a low pressure bottom feed fuel injector having an inlet portion fully received within a chamber of an adaptor housing having a lower portion attached to the exhaust conduit. The housing is provided with fuel flow openings to allow low pressure fuel to circulate around and cool the fuel injector inlet portion within the chamber. Fuel injected into the exhaust conduit is preferably targeted toward a vaporization member, within the exhaust conduit, operative to absorb heat from the exhaust gas and vaporize fuel deposited thereon. A plurality of inwardly extending mixing baffles within the exhaust conduit intermediate the vaporization member and the aftertreatment device extend the mixing path to improve fuel vaporization for assisting regeneration of the device.

A exhaust system and method for venting exhaust from an engine, such as a diesel engine, through an exhaust line coupled to the engine includes a first particulate filter disposed in the exhaust line and “close-coupled” with the engine, and a second particulate filter spaced a distance (d) from the first filter. The first particulate filter is “close-coupled” so that it operates in a passive regeneration mode to a greater extent than the second particulate filter. The first particulate filter may be a partial wall-flow filter including some plugged and some open channels. Some of the plugged channels may be plugged adjacent to an inlet end and others may be plugged adjacent to an outlet end. A partial wall-flow filter is also described having some unplugged flow-through channels and some plugged channels wherein some plugged channels are located adjacent to the inlet end and some are located adjacent to the outlet end.

Systems and methods to determine when regeneration of a diesel particulate filter (DPF) are presented. Such determination is made by indirectly determining soot accumulation in the DPF by monitoring soot accumulation on a regeneration burner spark plug based on the correlation between spark plug fouling and DPF soot loading. An ion current sensing circuit is used during periods of no flame to determine soot loading on the spark plug. When soot loading on the spark plug approaches an amount that could cause fouling of the spark plug, the ignition controller initiates a hot spark to burn the soot off the spark plug. The number of such cleaning events is tracked and used to determine when the DPF soot loading is at a level that regeneration should be initiated. Temperature rise across the DPF is monitored and used to adjust the number spark plug cleaning events needed before initiating regeneration.

The invention relates to a cerium-zirconium-tungsten composite oxide catalyst used for carrying out selective catalytic reduction on nitric oxide by ammonia, as well as a preparation method and usage thereof. The catalyst is a composite metal oxide formed by three types of metal including cerium, zirconium and tungsten. The catalyst adopts non-toxic and harmless raw materials; the cerium-zirconium-tungsten composite oxide catalyst which can adapt to high space velocity reaction condition and has the characteristics of being excellent in catalytic activity, high in N2 generation selectivity, wide in operating temperature window and the like can be prepared by using a simple and practicable method; and the cerium-zirconium-tungsten composite oxide catalyst is suitable for a nitric oxide catalytic purification device used for a moving source represented by diesel exhaust and a fixed source represented by flue gas of a coal-fired power plant.

An exhaust cleanup filter which, even if the exhaust temperature is low as during vehicular driving under low load, can trap PM efficiently to prevent clogging by PM buildup and which also is effective in purifying the exhaust from a diesel engine that does not use any burner or heater to remove PM. The cleanup filter is for purifying the exhaust from diesel engines and comprises particulate ceramic porous bodies that have a three-dimensional network structure, as well as artificial pores and communication channels in the interior, with some of the pores being partially exposed on the surfaces of the porous bodies.

A burner (18) is provided for use in a diesel exhaust gas treatment system (10) to treat an exhaust flow (12) from a diesel combustion process (14). The burner (18) includes an inner housing (34) defining a combustion flow path (40) to direct a first portion of the exhaust flow (12) through an ignition zone (42) wherein fuel is ignited, an outer housing (32) surrounding the inner housing (34) to define an annular bypass flow path (44) between the inner and outer housings (34, 32) to bypass a second portion of the exhaust flow (12) around the ignition zone (42), and a mixer (48) including a plurality of flow restrictor fingers (50) that extend across the bypass flow path (44) to restrict an available flow area of the bypass flow path (44), and a plurality of mixer fingers (52) having portions that extend inwardly from a location downstream from the inner housing (34).

An aluminum titanate-based ceramic body having a composition a formula comprising a(Al₂O₃.TiO₂)+b(CaO.Al₂O₃.2SiO₂)+c(SrO.Al₂O₃.2SiO₂)+d(BaO.Al₂O₃.2SiO₂)+e(3Al₂O₃.2SiO₂)+f(Al₂O₃)+g (SiO₂)+h(Fe₂O₃.TiO₂)+i(MgO.2TiO₂), wherein a, b, c, d, e, f, g, h, and i are weight fractions of each component such that (a+b+c+d+e+f+g+h+i)=1, wherein 0.5<a≦0.95; 0≦b≦0.5; 0≦c≦0.5; 0≦d≦0.5; 0<e≦0.5; 0≦f≦0.5; 0≦g≦0.1; 0≦h≦0.3; 0≦i≦0.3; b+d>0.01. A method of forming the ceramic body is provided. The ceramic body is useful in automotive emissions control systems, such as diesel exhaust filtration.