1759results about "Surface coverings" patented technology

Provided is an emission treatment system and method for simultaneously remediating the nitrogen oxides (NOx), particulate matter, and gaseous hydrocarbons present in diesel engine exhaust streams. The emission treatment system has an oxidation catalyst upstream of a soot filter coated with a material effective in the Selective Catalytic Reduction (SCR) of NOx by a reductant, e.g., ammonia. Also provided is a method for disposing an SCR catalyst composition on a wall flow monolith that provides adequate catalyst loading, but does not result in unsuitable back pressures in the exhaust.

Provided is an emissions treatment system and method for reducing NOx emissions in the exhaust stream produced from an internal combustion engine. The system has an injector for periodically metering ammonia or an ammonia precursor into an exhaust stream; and a first substrate with a first SCR catalyst composition, downstream of the injector. The first substrate has an inlet end, an outlet end, a length extending between the inlet end to the outlet end, wall elements and a plurality of passages defined by the wall elements. The first SCR catalyst composition is disposed on the wall elements from the inlet end toward the outlet end to a length that is less than the substrate's axial length to form an inlet zone. The first substrate also has an NH3 destruction catalyst composition with a platinum group metal component dispersed on a refractory metal oxide. The NH3 destruction catalyst is disposed on the wall elements from the outlet end toward the inlet end to a length that is less than the substrate's axial length to form an outlet zone. Generally, there is from 0.1 to 10 g / ft3 of platinum group metal component in the outlet zone.

An exhaust system for a vehicular positive ignition internal combustion engine comprises a filter for filtering particulate matter from exhaust gas emitted from the engine, which filter comprising a porous substrate having inlet and outlet surfaces, wherein the inlet surfaces are separated from the outlet surfaces by a porous structure containing pores of a first mean pore size, wherein the porous substrate is coated with a three-way catalyst washcoat comprising a plurality of solid particles wherein the porous structure of the washcoated porous substrate contains pores of a second mean pore size, which is less than the first mean pore size, and a three-way catalyst washcoat disposed on a separate substrate monolith located upstream of the filter, wherein a mass of three-way catalyst washcoat on the upstream substrate monolith is ≦75% of the total mass of three-way catalyst washcoat in the exhaust system.

A layered, three-way conversion catalyst having the capability of simultaneously catalyzing the oxidation of hydrocarbons and carbon monoxide and the reduction of nitrogen oxides is disclosed. In one or more embodiments, the catalyst comprises three layers in conjunction with a carrier: a first layer deposited on the carrier and comprising palladium deposited on a refractory metal oxide and an oxygen storage component; a second layer deposited on the first layer and comprising rhodium deposited on a refractory metal oxide and an oxygen storage component; and a third layer deposited on the second layer and comprising palladium deposited on a refractory metal oxide.

An exhaust treatment system includes an oxidation device having a plurality of channels through which a flow of exhaust flows. A first portion of the channels of the oxidation device are coated with catalytic material for converting NO to NO2 and a second portion of the channels are uncoated with the catalytic material. The exhaust treatment system also includes a selective catalytic reduction device disposed downstream from the oxidation device. The selective catalytic reduction device is configured to receive the flow of exhaust passing through the oxidation device.

An engine exhaust catalyst exhibits improved CO oxidation performance relative to conventional engine exhaust catalysts and includes a first supported catalyst comprising platinum and a second supported catalyst comprising palladium and gold species in close contact. The first supported catalyst may be a platinum catalyst, a platinum—palladium catalyst, or a platinum catalyst promoted with bismuth, and the second supported catalyst preferably has a palladium to gold weight ratio of about 0.85:1.0. To improve aged catalyst performance, the first and second supported catalysts are coated onto different layers, zones, or monoliths of the substrate for the engine exhaust catalyst.

Provided is a base metal undercoat containing catalyst and an exhaust article containing the catalyst. The catalyst contains a base metal undercoat with an oxygen storage component, and at least one catalytic layer. Also provided are methods for preparing the catalyst and methods for monitoring the oxygen storage capacity of an exhaust article containing the catalyst.

An emission control catalyst that exhibits improved CO and HC reduction performance includes a supported platinum-based catalyst, and a supported palladium-gold catalyst. The two catalysts are coated onto different layers, zones, or monoliths of the substrate for the emission control catalyst such that the platinum-based catalyst encounters the exhaust stream before the palladium-gold catalyst. Zeolite may be added to the emission control catalyst as a hydrocarbon absorbing component to boost the oxidation activity of the palladium-gold catalyst.

A catalyzed diesel particulate filter (CDPF) and a method for filtering particulates from diesel engine exhaust are provided, where the catalyzed diesel particulate filter includes a substrate and a catalyst composition, where the catalyst composition contains at least one first component, at least one second component, and at least one third component, where the first component is at least one first component selected from the group consisting of cerium and a lanthanide and mixtures thereof, the at least one second component is selected from the group consisting of cobalt, copper, manganese and mixtures thereof; and the third component comprises strontium, where the first component, the second component, and the third component are in an oxide form after calcination. The catalyst on the catalyzed diesel particulate filter lowers the temperature at which particulates are removed from the CDPF by oxidizing the particulates on the filter. The catalyzed diesel particulate filter may also include a washcoat. Washcoats prepared from colloidal aluminum oxide may have higher surface areas and pore volumes loadings than washcoats containing aluminum oxide prepared from aluminum nitrate.

A regeneration system for an exhaust gas cleaning device disposed in an exhaust emission path of an internal combustion engine has an exhaust gas cleaning honeycomb filter and a heating element for the filter, wherein the filter is a checkered SiC honeycomb filter having a given cell structure, and the heating element is a heater or a glow plug when using a fuel containing fuel additive.

The invention provides a catalyzed soot filter formed on a wall flow substrate having internal walls coated with catalyst compositions. The soot filter maintains a homogeneous flow of the exhaust gases through the internal walls of the substrate along the length of the filter due to the coating design. Both the efficiency and the durability of the catalytic function are increased over conventionally designed catalyzed soot filters. The catalyzed soot filter provides an integrated function for simultaneously treating the gaseous components of the exhaust (e.g., CO and HC) and the particulate matter deposited in the filter.

A multi-layer emission control catalyst exhibits improved CO and HC reduction performance. The bottom layer includes a supported catalyst comprising platinum and palladium particles or palladium and gold particles. The middle layer includes zeolites. The top layer includes a supported catalyst comprising platinum and palladium particles. The use of zeolite mixture in the middle layer further improves CO and HC reduction performance in comparison with using zeolite of a single type. The use of a supported catalyst comprising palladium and gold particles in the bottom layer further improves CO and HC reduction performance in comparison with using a supported catalyst comprising platinum and palladium particles.

An exhaust gas purifying catalyst is constructed by laminating sequentially a first layer containing alumina, a second layer containing hydrocarbon adsorbent, and a third layer containing catalytic components on a monolithic support in which a cell sectional shape is a polygon. The second layer has a ratio Lmax / Lmin of a thickest portion (Lmax) at cell corner portions to a thinnest portion (Lmin) at cell flat portions in a range of 1 to 10, and has a thickness of 10 to 500 mum. The catalyst can achieve the purification of HC, CO, and NOx with good balance, and improve the purification performance of cold HC by controlling a diffusion speed of the exhaust gases that pass through cells in a support and diffuse into a coating layer.

An oxidation catalyst deposited on a filter substrate for the removal of CO, hydrocarbons, and particulate matter, such as soot, from an exhaust stream wherein the oxidation catalyst is formed from a platinum group metal supported on a refractory oxide, tin oxide, and a zeolite.