Abstract:
Described are exhaust gas treatment systems for treatment of a gasoline engine exhaust gas stream containing NOx, particulate matter, and sulfur. The exhaust gas treatment system comprises: one or more catalytic articles selected from a three-way conversion catalyst (TWC), a lean NOx trap (LNT), and an integrated LNT-TWC; a platinum-containing catalytic article downstream from the one or more catalytic articles; and one or more selective catalytic reduction (SCR) catalytic articles immediately downstream from the platinum-containing catalytic article, the one or more SCR catalytic articles including a molecular sieve. The system stabilizes the SCR catalytic article from poisoning by sulfur.
Abstract:
Disclosed is a catalyzed soot filter with layered design. The first coating of the filter comprises an oxidation catalyst comprising platinum (Pt) and optionally palladium (Pd). The second coating of the filter comprises an oxidation catalyst comprising Pd and optionally Pt, wherein the Pt concentration in the second coating is lower than the Pt concentration in the first coating and wherein the weight ratio of Pt:Pd in the second coating is in the range of from 1 : 1 to 0 : 1; and wherein the first coating and the second coating are present on the wall flow substrate at a coating loading ratio in the range of from 0.25 to 3, calculated as ratio of the loading of the first coating (in g/inch3 (g/(2.54cm)3)): loading of the second coating (in g/inch3 (g/(2.54cm)3)).
Abstract:
Wall flow monolithic honeycomb filter having including microcracks having an average width less than 0.4 μm, and pores having a mean pore size in the range of 10 μm to 25 μm; and a washcoat disposed within the walls of the wall flow monolith, the washcoat including catalyst comprising support particles and at least one precious metal, where at least 90% of the support particles have particle sizes greater than the average size of the microcracks and at least 90% of the support particles have particle sizes less than the mean size of the pores of the wall flow monolith. The wall flow monolith comprises aluminum titanate having a porosity in the range of 40%. to 70%, wherein the soot filter shall exhibit a coefficient of thermal expansion less than 25 x 10-7/K when measured at 1000°C preferably less than 5 x 10-7/K when measured at 800 °C.
Abstract:
Provided are multi-zone catalyst articles, methods of manufacturing multi-zone catalyst articles, and methods for controlling emissions in diesel engine exhaust streams with multi-zone catalyst articles, where the emission treatment system of various embodiments effectively treats diesel engine exhaust with a single multi-zone catalyst article.
Abstract:
A catalyzed soot filter, in particular for the treatment of Diesel engine exhaust, comprises a coating design which ensures soot particulates filtration, assists the oxidation of carbon monoxide (CO), and produces low H2S emissions during normal engine operations and regeneration events.
Abstract:
Provided are diesel exhaust components where palladium is segregated from a molecular sieve, specifically a zeolite, in a catalytic material. In the catalytic material, therefore, there are at least two layers: a palladium-containing layer that is substantially free of a molecular sieve and a hydrocarbon trap layer that comprises at least one molecular sieve and is substantially free of palladium. The palladium is provided on a high surface area, porous refractory metal oxide support. The catalytic material can further comprise a platinum component, where a minor amount of the platinum component is in the hydrocarbon trap layer, and a majority amount of the platinum component is in the palladium-containing layer. Systems and methods of using the same are also provided.
Abstract:
Provided are exhaust systems and components suitable for use in conjunction with gasoline direct injection (GDI) engines to capture particulates in addition to reducing gaseous emission such as hydrocarbons, nitrogen oxides, and carbon monoxides. Exhaust treatment systems comprising a three-way conversion (TWC) catalyst located on a particulate trap are provided. An exemplary particulate trap is a soot filter. Additional treatment components can be added downstream of the particulate trap, including NOtraps and SCR catalysts. The TWC catalyst can be coated on both the inlet side and the outlet side of the particulate trap. Alternatively, an oxidation catalyst can be deposited on a particulate trap. Methods of making and using the same are also provided.