A catalyst device includes a catalyst support, a tubular portion, which accommodates the catalyst support, a holding mat, which holds the catalyst support, an insulator provided over the outer circumferential surface of the tubular portion, and a heat insulating member arranged between the insulator and the tubular portion. The region of the outer circumferential surface of the tubular portion between the upstream end and the downstream end in the exhaust gas flowing direction is divided into two subregions arranged in a direction of the axis of the tubular portion. Of the two subregions, the subregion on the upstream side is defined as an upstream subregion, and the subregion on the downstream side is defined as a downstream subregion. The area that is covered with the heat insulating member in the downstream subregion is smaller than the area that is covered with the heat insulating member in the upstream subregion.

A fibre mat, for example a monolith support mat or end cone insulator, the mat comprising inorganic fibres having a pressure retained value at 10 minutes at 900 C. of greater than 20 kPa; and preferably a binder. The inorganic fibres comprise X and Y and K.sub.2O, the sum of which is greater than 95 wt. % wherein X is the sum of SiO.sub.2 and ZrO.sub.2 and Y is the sum of Al.sub.2O.sub.3 and La.sub.2O.sub.3, wherein ZrO.sub.2 and La.sub.2O.sub.3 is each present in up to 10 wt. % of the total weight of the inorganic fibres.

A catalyst device includes a catalyst support, a tubular portion, which accommodates the catalyst support, a holding mat, which holds the catalyst support, an insulator provided over the outer circumferential surface of the tubular portion, and a heat insulating member arranged between the insulator and the tubular portion. The region of the outer circumferential surface of the tubular portion between the upstream end and the downstream end in the exhaust gas flowing direction is divided into two subregions arranged in a direction of the axis of the tubular portion. Of the two subregions, the subregion on the upstream side is defined as an upstream subregion, and the subregion on the downstream side is defined as a downstream subregion. The area that is covered with the heat insulating member in the downstream subregion is smaller than the area that is covered with the heat insulating member in the upstream subregion.

Mats comprising a non-woven layer and a first polymeric layer on a major surface thereof. The mats are useful, for example, a mounting mats for pollution control devices, as well as thermal and acoustic insulation for pollution control devices and exhaust systems.

A mounting mat for an exhaust gas treatment device, includes at least one layer comprising inorganic fibers and a heater in thermal communication with the layer. Also disclose is an exhaust gas treatment device comprising an outer housing, a fragile structure located in the housing and the mounting mat located between the housing and the fragile structure. A method is further disclosed for maintaining and/or increasing the temperature of a substrate of an exhaust gas treatment device comprising providing the mounting mat and transferring heat from the heater to the mounting mat in order to maintain and/or increase the temperature of the substrate and/or the exhaust gas treatment device during the battery mode of a hybrid gas/electric vehicle.

A method for encasing a body of an exhaust gas system with a housing which is wound around the body. Using a winding method, the body is placed in a loop formed by a belt-shaped conveyor element that can be driven in a conveyor device, wherein the conveyor element is seated against the outer casing face at a wrapping angle u of at least 270 degrees. Starting with a first edge, the metal strip is then introduced in a conveyor device between the body and the conveyor element, is drawn into the gap between the body and the conveyor element and is bent around the body until the body is encased at least twice by the metal strip.

Provided are an inorganic fiber-formed article having both high basis weight and excellent peel strength and a mat for an exhaust gas cleaning apparatus and an exhaust gas cleaning apparatus including the inorganic fiber-formed article. The inorganic fiber-formed article includes inorganic fibers and needle marks extending in the thickness direction and including vertical bundles composed of the inorganic fibers extending in the thickness direction, in which the average volume of the vertical bundles per needle mark measured by a prescribed peel test is 1.0 mm.sup.3 or more.

A mat for mounting a monolith, the mat comprising a first inorganic fiber layer, where the mat has a front edge intended to form a gas facing edge in use, a rear edge opposite thereto and side edges extending between the front and rear edges, wherein the first inorganic fiber layer at a first side edge of the mat, and/or at a second side edge of the mat is cut at an acute angle to the thickness direction of the mat.

A catalytic converter holding mat that is inexpensive, and exhibits an excellent heat insulation capability is provided by utilizing an inexpensive heat insulating material that exhibits an excellent heat insulation capability. The catalytic converter holding mat is provided in a gap between a tubular catalyst carrier and a casing that houses the catalyst carrier, and includes a retaining section that is formed of first inorganic fibers having a thermal shrinkage ratio at 1000 C. of 1% or less, and an insulation section that is disposed adjacent to the retaining section, and formed of second inorganic fibers having a thermal shrinkage ratio at 1000 C. of more than 1%.

A mounting mat for a pollution control device is disclosed. The device comprises at least a first sheet and a second sheet and at least one holding means for holding the at least first and second sheets together. The holding means are adapted to (i) hold the at least first and second sheets together while allowing movement of the at least first and second sheets parallel to each other in the region where the holding means is positioned; and/or (ii) to break upon wrapping around a body thereby allowing movement of the at least first and second sheets parallel to each other in the region where the holding means is positioned. A pollution control device containing such a mat and method of making a pollution control device containing such a mat are also disclosed.