The invention relates to a catalytic converter for treating exhaust gases of an internal combustion engine, having a housing through which an exhaust gas may flow and which has an inflow side and an outflow side, wherein, in the housing, there is formed a plurality of flow channels (4, 13) which is flowed through along a main throughflow direction from the inflow side to the outflow side, wherein, in the housing, there is arranged at least one pipeline (5, 12) which is flowed through by a fluid which is independent of the exhaust gas that is caused to flow through the flow channels (4, 13).

An oxidation catalyst for treating an exhaust gas from a diesel engine comprises: a first washcoat region for oxidising carbon monoxide (CO) and hydrocarbons (HCs), wherein the first washcoat region comprises a first platinum group metal (PGM) and a first support material, and wherein the first washcoat region does not comprise manganese or an oxide thereof; a second washcoat region for oxidising nitric oxide (NO), wherein the second washcoat region comprises platinum (Pt), manganese (Mn) and a second support material comprising a refractory metal oxide, which is silica-alumina or alumina doped with silica in a total amount of 0.5 to 45% by weight of the alumina, wherein the platinum (Pt) is disposed or supported on the second support material and the manganese (Mn) is disposed or supported on the second support material; and a substrate having an inlet end and an outlet end, and wherein the first washcoat region is a first washcoat layer and the second washcoat region is a second washcoat layer, and the second washcoat layer is disposed on the first washcoat layer; and wherein when the oxidation catalyst comprises a hydrocarbon adsorbent, which is a zeolite, then the first washcoat region further comprises the hydrocarbon adsorbent.

The present disclosure relates to an exhaust gas treatment system for treating an exhaust gas stream leaving an internal combustion engine, wherein said exhaust gas treatment system comprises (i) a first catalyst comprising a coating and a first substrate, wherein the coating comprises a vanadium oxide supported on a first oxidic support comprising titanium; (ii) a hydrocarbon injector for injecting a fluid comprising hydrocarbons into the exhaust gas stream exiting the outlet end of the first catalyst according to (i); (iii) a second catalyst comprising a coating and a second substrate, wherein the coating comprises palladium on a second oxidic support comprising one or more of zirconium, silicon, aluminum and titanium.

Certain selective catalytic reduction (SCR) articles, systems and methods provide for high NOx conversion while at the same time low N.sub.2O formation. The articles, systems and methods are suitable for instance for the treatment of exhaust gas of diesel engines. Certain articles have zoned coatings containing copper-containing molecular sieves disposed thereon, where for example a concentration of catalytic copper in an upstream zone is lower than the concentration of catalytic copper in a downstream zone.

An exhaust aftertreatment system includes a cross-flow selective catalytic reduction catalyst. The cross-flow selective catalytic reduction catalyst includes a housing and a substrate assembly. The substrate assembly includes a plurality of first substrate layers defining a plurality of first flow channels and a plurality of second substrate layers defining a plurality of second flow channels. The exhaust aftertreatment system includes a passive NO.sub.x adsorber. The passive NO.sub.x adsorber includes a housing. The housing includes an inlet in exhaust gas receiving communication with the plurality of first flow channels of the cross-flow selective catalytic reduction catalyst. The housing includes an outlet in exhaust gas providing communication with the plurality of second flow channels of the cross-flow selective catalytic reduction catalyst. The passive NO.sub.x adsorber includes a substrate positioned in the housing. The substrate includes a passive NO.sub.x adsorber washcoat.

The present disclosure is directed to a catalytic composite that comprises porous supported catalyst particles durably enmeshed in a porous fibrillated polymer membrane. The supported catalyst particles are composed of at least one metal or metal oxide catalyst dispersed on a porous support substrate. In some embodiments, the porous fibrillated polymer membrane is perforated or otherwise contains mechanically formed holes therein. The supported catalyst particles have a large particle population based, at least in part, a D90 value greater than 60 microns. The catalytic membrane composite may be used in filtration applications to remove air-polluting substances such as SOx, NOx, dioxin/furan, CO, and others and convert them into non-polluting or less-polluting gas components. Additionally, the catalytic article may be in the form of a filter bag, a honeycomb, a monolith or any other suitable geometrically structured forms.

A muffler is detachably attached to an engine. A catalyst for purifying exhaust gas is provided upstream of the muffler, and a secondary air valve for supplying air to an exhaust passage is provided upstream of the catalyst. The catalyst and the secondary air valve are integrally unitized. A catalyst unit including the catalyst and the secondary air valve is provided between the engine and the muffler.

A catalyst arrangement deciding method for a flue gas denitrizer including a catalyst layer disposed in an exhaust gas passage includes: a step of investigating a location dependence of a degradation state of a catalyst in the catalyst layer after a lapse of a period of operation; and a step of deciding a first region of the catalyst layer in which a first catalyst is used and a second region of the catalyst layer in which a second catalyst different from the first catalyst is used, on the basis of the location dependence.

A process for the removal of nitrous oxide (N.sub.2O) contained in a process off-gas in an axial flow reactor. The process includes the steps of (a) adding an amount of reducing agent into the process off-gas; (b) in a first stage passing in axial flow direction the process off-gas admixed with the reducing agent through a first monolithic shaped catalyst active in decomposing nitrous oxide by reaction with the reducing agent to provide a gas with a reduced amount of nitrous oxide and residual amounts of reducing agent; and (c) in a second stage passing the gas with a reduced amount of nitrous oxide and residual amounts of the reducing agent in axial flow direction through a second monolithic shaped catalyst active in oxidation of the residual amounts of the reducing agent.

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.