A molded three-dimensional insulator that is suitable for use in an end cone region of a pollution control device and a method of making the insulator are described. The insulator includes ceramic fibers that have a bulk shrinkage no greater than 10 weight percent. The ceramic fibers can contain alumina and silica and can be microcrystalline, crystalline, or a combination thereof.

A catalyst unit includes: a ceramic catalyst body through which exhaust gas flows and having a substantially cuboid contour with a substantially rectangular inflow side and a substantially rectangular outflow side; a housing that at least partially encloses the catalyst body, and at least one bearing mat positioned in a gap formed between the catalyst body and the housing. Borders or edges of the catalyst body, which delimit the inflow side and the outflow side, each have dimensions of between 210 mm and 280 mm. The gap between the catalyst body and the housing, seen perpendicularly to the throughflow direction of the catalyst body, has a dimension determined according to the following relationship: sp*5, s being the dimension of the gap in mm and p the dimensionless amount of the density of the or each bearing mat expressed in kg/m2.

In a catalytic converter having a catalyst support that generates heat by being energized, short circuiting due to soot within exhaust is suppressed. A catalyst support is provided in a range of a glass coat layer that is provided on an inner surface of a tube body. A maximum diameter portion of an upstream side reduced diameter member and a maximum diameter portion of a downstream tube are positioned in the range of the glass coat layer.

In one embodiment, there is disclosed an apparatus for decontaminating exhaust gasses. The apparatus includes a monolith catalytic substrate having a length and a width. The substrates length separates first and second opposed ends. The first end and second ends each have a one piece retention ring fitted thereon. The apparatus includes a housing having a length separating opposed, spaced apart open first and second ends. The housing has a side wall extending substantially unbroken there between to define a body having an interior space. The monolith catalytic substrate is disposed in said interior space. The housing has a greater length than said monolith catalytic substrate. The substrate is centered in the housing and the housing is swaged at the first and second ends respectively to engage the retention rings and retain the monolith catalytic substrate within the interior space in said housing.

A catalyst unit for an exhaust gas catalyst, having a ceramic catalyst body, and a metallic housing which encloses the catalyst body at least in some sections perpendicular to a gas throughflow direction. At least one bearing mat positioned between the catalyst body and the housing perpendicular to the throughflow direction. The catalyst body is retained in the housing via a force-closed press fit with the intermediate arrangement of the or each bearing mat such that, when seen in the throughflow direction of the catalyst body, the press fit between the housing and the catalyst body is formed exclusively at defined axial positions, the housing having groove-like depressions at the defined axial positions for reducing in some sections the inner cross-section of the housing, and the press fit between the housing and the catalyst body being formed exclusively in the region of the groove-like depressions.

A molded three-dimensional insulator that is suitable for use in an end cone region of a pollution control device and a method of making the insulator are described. The insulator includes ceramic fibers that have a bulk shrinkage no greater than 10 weight percent. The ceramic fibers can contain alumina and silica and can be microcrystalline, crystalline, or a combination thereof.

An exhaust system includes an exhaust gas treatment article having a porous ceramic honeycomb body mounted in a housing. The housing can be a low expansion housing and includes an outer shell having a first coefficient of thermal expansion (CTE) and an inner wall having a second CTE greater than the first CTE configured to hold the honeycomb body over operating temperatures.

There is provided a zeolite having a CHA structure. When a total integrated intensity of a (211) plane, a (104) plane, and a (220) plane in an X-ray diffraction spectrum obtained by an X-ray powder diffraction method is defined as X.sub.0 and the total integrated intensity after heat endurance test for five hours at 900 C. under an air atmosphere is defined as X.sub.1, a ratio of X.sub.1 (X.sub.1/X.sub.0) to X.sub.0 is within a range from 0.2-0.7; and as measured by a .sup.27Al-NMR method after the heat endurance test for five hours at 900 C. under the air atmosphere, when a peak intensity of tetra-coordinated Al atoms is defined as P.sub.4 and a peak intensity of hexa-coordinated Al atoms is defined as P.sub.6, a ratio of P.sub.6 (P.sub.6/P.sub.4) to P.sub.4 is 0.1 or less.

An article, includes a porous ceramic honeycomb body and a housing disposed on at least one of an outer periphery of the porous ceramic honeycomb body and opposing end faces of the porous ceramic honeycomb body, wherein the housing exerts a compressive force on the porous ceramic honeycomb body in at least one of radial direction and axial direction. A method of making the article, includes heating to greater than or equal to about 200 C the housing, crimping the housing tightly around the honeycomb body while the housing is greater than or equal to about 200 C, and cooling the housing. The housing exerts a compressive force on the porous ceramic honeycomb body in at least one of radial direction and axial direction by shrinking on cooling more than the honeycomb body.

A catalyst unit for an exhaust gas catalyst, having a ceramic catalyst body, and a metallic housing which encloses the catalyst body at least in some sections perpendicular to a gas throughflow direction. At least one bearing mat positioned between the catalyst body and the housing perpendicular to the throughflow direction. The catalyst body is retained in the housing via a force-closed press fit with the intermediate arrangement of the or each bearing mat such that, when seen in the throughflow direction of the catalyst body, the press fit between the housing and the catalyst body is formed exclusively at defined axial positions, the housing having groove-like depressions at the defined axial positions for reducing in some sections the inner cross-section of the housing, and the press fit between the housing and the catalyst body being formed exclusively in the region of the groove-like depressions.