Provided is a catalyst structure which prevents an increase in pressure loss by a simple construction while the gas flow is efficiently stirred by a structure making contact between adjacent catalyst elements. The catalyst structure is provided with a first flat-plate part and a second flat-plate part which support, on surfaces thereof, a constituent having catalytic activity to an exhaust gas and face each other, and a stirring part which is provided in such a manner as to come into contact first with the first flat-plate part and the second flat-plate part in an extending manner from the first flat-plate part to the second flat-plate part at a prescribed angle with respect to the direction in which the exhaust gas flows.

The honeycomb structure includes a pillar-shaped honeycomb structure body having porous partition walls, as to the honeycomb structure body, in a plane perpendicular to a cell extending direction, a cell structure of a central cell structure differs from a cell structure of a circumferential cell structure, and in the plane, a geometric center of gravity of the honeycomb structure body exists at a position which is away from a geometric center of gravity of the central cell structure, and a distance between the respective centers of gravity is larger than a length of a half of a cell pitch of an outermost circumferential cell structure including complete cells formed at an outermost circumference of the honeycomb structure body.

A diesel engine emissions catalyst which may be used to fill a niche between standard oxidation catalyst and diesel particulate filters for control of diesel particulate matter. The catalyst includes a structure (substrate) comprising one or more coated, corrugated micro-expanded metal foil layers. The coated surface may be a high surface area, stabilized, and promoted washcoat layer. The corrugated pattern may include a herringbone-style pattern that, when in use, is oriented in a longitudinal direction of the diesel engine exhaust flow. The micro-expanded metal foil provides small openings or eyes that, as the exhaust flow passes through the catalyst (transverse to the eye opening), particulates in the flow impinge on the surface and becomes trapped in the eyes. The catalyst may be used to treat a locomotive engine exhaust stream and may be used with a selective catalyst reduction system.

A ceramic honeycomb structure having a web structure including a plurality of intersecting channel walls forming channels. The ceramic honeycomb structure has a total porosity greater than or equal to about 55%, an average channel wall thickness less than or equal to about 150 μm, a median pore diameter greater than or equal to about 10 μm, a d.sub.f less than or equal to about 0.45, where d.sub.f=(d.sub.50−d.sub.10)/d.sub.50, and a strength (MOR/CFA) greater than or equal to about 900 psi. A method of manufacturing a ceramic honeycomb structure by mixing a ceramic precursor batch composition having a median particle diameter less than or equal to about 10 μm and at least one starch-based pore former having a median particle diameter greater than or equal to about 10 μm. The method also includes forming a mixture of ceramic precursor batch composition and a starch-based pore former into a green ceramic structure having a web structure, and firing the green ceramic structure to yield a ceramic honeycomb structure.

A diesel engine emissions catalyst which may be used to fill a niche between standard oxidation catalyst and diesel particulate filters for control of diesel particulate matter. The catalyst includes a structure (substrate) comprising one or more coated, corrugated micro-expanded metal foil layers. The coated surface may be a high surface area, stabilized, and promoted washcoat layer. The corrugated pattern may include a herringbone-style pattern that, when in use, is oriented in a longitudinal direction of the diesel engine exhaust flow. The micro-expanded metal foil provides small openings or eyes that, as the exhaust flow passes through the catalyst (transverse to the eye opening), particulates in the flow impinge on the surface and becomes trapped in the eyes. The catalyst may be used to treat a locomotive engine exhaust stream and may be used with a selective catalyst reduction system.

A honeycomb body comprises a matrix of intersecting porous walls forming channels. Plugs are disposed in a percentage of the channels having the second hydraulic diameter, wherein the percentage of the channels of the second diameter having a plug is less than or equal to 15%. In some embodiments, some of the channels have a first hydraulic diameter and others have a second hydraulic diameter that is smaller than the first hydraulic diameter, and may be unplugged for plugged. The porous walls can further comprise a transverse thickness of the walls Tw less than or equal to 0.20 mm, a channel density CD greater than or equal to 62 channels per cm.sup.2, an average bulk porosity % P greater than or equal to 50%, and a median pore diameter d.sub.50 ranging from between 4.0 μm and 30.0 μm.

A thin-walled honeycomb body (100) having a plurality of repeating cell structures (110) formed of intersecting porous thick walls (112V, 112H) and thin walls (114V, 114H). Each repeating cell structure (110) is bounded on its periphery by the thick walls (112V, 122H) of a first transverse thickness (Tk) and the thin walls (114V, 114H) have a second transverse thickness (Tt) that subdivides each repeating cell structure (110) into between 7 and 36 individual cells (108). In the thin-walled honeycomb body (100), the first transverse thickness (Tk) of the thick walls (112V, 112H) is less than or equal to 0.127 mm (0.005 inch) and the second transverse thickness (Tt) of the thin walls (114V, 114H) is less than or equal to 0.0635 mm (0.0025 inch), and Tk>Tt. Honeycomb extrusion dies and methods of manufacturing the thin-walled honeycomb body (100) having thick walls (112V, 112H) and thin walls (114V, 114H) are provided.

Catalyzed particulate filters comprise three-way conversion (TWC) catalytic material that permeates walls of a particulate filter such that the catalyzed particulate filter has a coated porosity that is less than an uncoated porosity of the particulate filter. The coated porosity is linearly proportional to a washcoat loading of the TWC catalytic material. A coated backpressure is non-detrimental to performance of the engine. Such catalyzed particulate filters may be used in an emission treatment system downstream of a gasoline direct injection engine for treatment of an exhaust stream comprising hydrocarbons, carbon monoxide, nitrogen oxides, and particulates.

A ceramic honeycomb body, suitable for use in exhaust gas processing, includes a honeycomb structure having a plurality of through-channels, a first portion of the plurality of through-channels have a first hydraulic diameter dh1, a second portion of the plurality of through-channels have a second hydraulic diameter that is smaller than the first hydraulic diameter dh1, the first hydraulic diameter dh1 is equal to or greater than 1.1 mm, and the first and second portions of through-channels, taken together, have a geometric surface area GSA greater than 2.9 mm.sup.−1. Diesel oxidation catalysts and methods of soot removal are also provided, as are other aspects.

A silicon carbide ceramic honeycomb structure having large numbers of axially penetrating flow paths partitioned by porous silicon carbide cell walls, the cell walls comprising silicon carbide particles as aggregate and binder layers for binding the silicon carbide particles, the binder layers having at least a cordierite phase and a spinel phase, and the molar ratio M1 of the cordierite phase [=cordierite phase/(cordierite phase+spinel phase)] being 0.4-0.9.