The present invention provides an exhaust gas purifying filter capable of efficiently burning and removing particulates captured by a partition wall, and a production method thereof. This exhaust gas purifying filter (CSF) of the present invention includes at least a honeycomb substrate having a porous partition wall configured to capture particulates (PM) such as soot in exhaust gas, and a catalyst carried by the honeycomb substrate and configured to burn and remove the particulates captured by the partition wall of the honeycomb substrate and deposited within cells, wherein the catalyst is carried concentrically in a shallow portion from the surface of the cell wall on the exhaust gas inflow side of the honeycomb substrate, and 65% or more of the total mass of the catalyst is present in a depth region from the surface of the cell wall of the honeycomb substrate up to 2/10 a with reference to the wall thickness a of the partition wall.

The present invention relates to a wall-flow filter for removing particles from the exhaust gas of combustion engines, comprising a wall-flow filter substrate of length L and coatings Z and F that differ from one another, wherein the wall-flow filter substrate has channels E and A, which extend in parallel between a first and a second end of the wall-flow filter substrate, are separated by porous walls and form surfaces O.sub.E and O.sub.A respectively, and wherein the channels E are closed at the second end and the channels A are closed at the first end, and wherein the coating Z is located in the porous walls and/or on the surfaces O.sub.A, but not on the surfaces O.sub.E, and comprises palladium and/or rhodium a cerium/zirconium mixed oxide, characterized in that the coating F is located in the porous walls and/or on the surfaces O.sub.E, but not on the surfaces O.sub.A and comprises a particulate metal compound and no noble metal.

Catalytic articles comprising a substrate having a catalytic coating thereon, the catalytic coating comprising a catalytic layer having a thickness and an inner surface proximate to the substrate and an outer surface distal to the substrate; where the catalytic layer comprises a noble metal component on support particles and where the concentration of the noble metal component towards the outer surface is greater than the concentration towards the inner surface are highly effective towards treating exhaust gas streams of internal combustion engines. The articles are prepared via a method comprising providing a first mixture comprising micron-scaled support particles and applying the first mixture to a substrate to form a micro-particle layer; providing a second mixture comprising nano-scaled support particles and a noble metal component having an initial pH and applying the second mixture to the micro-particle layer and calcining the substrate.

A vortex flow catalytic conversion apparatus and a method of vortex flow catalytic conversion of a fluid is provided. The apparatus includes a housing having an interior surface defining a cylindrical chamber. A helical separator is disposed within the chamber and cooperates with the interior side wall of the chamber to define a helical passageway for inducing a vortex flow. A deflector is disposed downstream of the helical separator to redirect the vortex flow exiting the helical passageway to an axial flow. A catalytic converter is disposed in the chamber downstream of the deflector. A catalyst coating is applied to at least one of the interior surface, helical separator, and catalytic converter. The method includes exposing a vortex flow of fluid to a first catalyst coating. The vortex flow is then redirected to an axial flow and exposed to a second catalyst coating.

The exhaust gas cleaning catalyst according to the present invention is provided with a cylindrical substrate 10 and a catalyst coat layer 20 formed on the surface of the substrate 10. A ratio of the length L in the cylindrical axis direction of the substrate 10 and the diameter D of a cross section orthogonal to the cylindrical axis direction is denoted by (L/D)0.8. The coat density of the catalyst coat layer 20 differs between an upstream side portion 10a that includes the exhaust gas inlet-side end 16 of the substrate 10 and a downstream side portion 10b that includes the exhaust gas outlet-side end 18 of the substrate 10. The coat density A in the upstream side portion 10a is lower than the coat density B in the downstream side portion 10b (A<B).

An exhaust gas purification device of the present invention is provided with: a substrate of wall flow structure having an inlet cell, an outlet cell and a porous partition wall; an upstream catalyst layer, provided inside the partition wall and disposed in an upstream portion of the substrate including an exhaust gas inflow end section; and a downstream catalyst layer, provided inside the partition wall and disposed in a downstream portion of the substrate including an exhaust gas outflow end section. The upstream catalyst layer and the downstream catalyst layer each contain a carrier and at least one noble metal from among Pt, Pd and Rh, supported on the carrier. The noble metal in the upstream catalyst layer and the noble metal in the downstream catalyst layer are different from each other.

The invention relates to a particle filter, which comprises a wall flow filter and SCR-active material, wherein the wall flow filter comprises ducts which extend in parallel between the first and the second end of the wall flow filter and which are alternately closed in a gas-tight manner either at the first or the second end and which are separated by porous walls, the pores of which have inner surfaces, and the SCR-active material is located in the form of a coating on the inner surfaces of the pores of the porous walls, characterized in that the coating has a gradient, such that the side of the coating facing the exhaust gas has a higher selectivity in the SCR reaction than the side of the coating that faces the inner surfaces of the pores. The SCR-active material is preferably a small-pore zeolite, which has a maximum ring size of eight tetrahedral atoms and is exchanged with copper and/or iron.

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 gas purifying device includes: a columnar honeycomb carrier in which a plurality of cells which extend from an exhaust gas inflow side to an outflow side, and which serve as exhaust gas flow paths, are demarcated and formed by means of porous separating walls, a three-way catalyst supported in the honeycomb carrier, and a cylindrical case member in which the honeycomb carrier is housed, with the interposition of a retaining member. The honeycomb carrier includes outer circumferential plugging portions formed in such a way as to plug, to a prescribed depth, openings of cells in an outer circumferential portion of at least one end surface of the two end surfaces, in the central axis X-direction, of the honeycomb carrier, and inclined portions formed in a direction whereby the length, in the central axis X-direction, of the outer circumferential plugging portions decreases toward the outer circumferential edge.

An oxidation catalyst may include hydrocarbon storage material. One implementation relates to a diesel oxidation catalyst that includes a catalyst having a front zone and a rear zone and a gradient of hydrocarbon storage material on the catalyst extending from the front zone to the rear zone. The gradient of hydrocarbon storage material, may comprise a linear gradient, a step gradient, a parabolic gradient, a logarithmic gradient, or other forms thereof.