Abstract: The web (8) is arranged around a processing unit (14) between the processing unit (14) and an envelop (16) which defines a conduit (12) for the exhaust gas flow. The web (18) includes a mattress whose external side is provided with an aluminosilicate-containing coating (30). The invention is used for motor vehicle exhaust lines.

Abstract: An exhaust pipe includes a thin metal tube having a wall thickness of less than 1 mm and, over at least a portion of its length, a peripheral sheath formed from a thermally expandable material.

Abstract: An exhaust volume (20) of the type including a muffler (24) having a casing provided with an inlet (29) and an outlet (30) for passing gases and adapted to enable the muffler to be mounted in an exhaust system (14). The volume further includes an additional enclosure (26) forming an accumulation cavity communicating solely with the casing of the muffler (24) via at least one connection pipe (28), the additional enclosure (26) being placed outside the muffler (24). The additional enclosure (26) is of a structure whose ability to withstand high temperature is lower than that of the structure of the muffler (24).

Abstract: An exhaust volume (20) of the type including a muffler (24) having a casing provided with an inlet (29) and an outlet (30) for passing gases and adapted to enable the muffler to be mounted in an exhaust system (14). The volume further includes an additional enclosure (26) forming an accumulation cavity communicating solely with the casing of the muffler (24) via at least one connection pipe (28), the additional enclosure (26) being placed outside the muffler (24). The additional enclosure (26) is of a structure whose ability to withstand high temperature is lower than that of the structure of the muffler (24).

Abstract: A composition for purifying exhaust gases of an internal combustion engine capable of consuming fuel with lean air-fuel ratios includes elements adsorbing the NOx present in the exhaust gases, in the presence of excess oxygen and releasing the adsorbed NOx when the oxygen concentration of the exhaust gases decreases. The NOx adsorbing element includes in combination: a first composition comprising a support and an active phase, the active phase being based on manganese and at least another element A selected among, alkalines and alkaline-earths, the manganese and element A being chemically bound; a second composition including a support and an active phase based on manganese and at least another element B selected among alkalines, alkaline-earths and rare earths, the second composition having or being capable of having a specific surface area of at least 80 m2/g after being calcined at 800° C., and furthermore, a reducing and/or three-way catalyst function is incorporated in the NOx adsorbing element.

Abstract: A device for purification of exhaust gases of an internal combustion engine capable of achieving combustion of a fuel with lean air-fuel ratios. A NOx-adsorbing mechanism is installed in the exhaust line of the engine. That NOx-adsorbing mechanism can absorb the NOx present in the exhaust gases in the presence of excess oxygen and can release the absorbed NOx when the oxygen concentration of the exhaust gases decreases. The NOx-adsorbing mechanism does not contain any composition capable of acting as an NOx reduction catalyst, and especially no precious metal, and further a three-way catalyst is installed in the exhaust line downstream from the NOx-adsorbing mechanism.

Abstract: A process for preparing hexaferrite particles of the type M'Fe.sub.12 O.sub.19 wherein M' represents principally an alkaline earth metal involves preparing a particulate mixture of a ferrous salt of an organic acid and a salt of an organic acid with at least one metal M', optionally with at least one dopant agent, the particles of the mixture having a size not greater than about 0.5 .mu.m and the said mixture containing a stoichiometric excess of the salt of metal M'. This mixture is heated up to the decomposition of the organic salts and the resulting product is submitted to a thermal treatment at a temperature at least equal to 700.degree. C. but not greater than 1000.degree. C. and is maintained at this temperature for a period of time sufficient to form hexaferrite. After cooling the resulting particles are washed with an aqueous solution of an acid capable of dissolving formed monoferrites of the type M'Fe.sub.2 O.sub.4 to remove them.

Abstract: The invention relates to an endocavitary cardiac stimulation probe. This probe comprises a tubular electrode connected to a cardiac stimulator by a flexible tubular insulated conductor. A harpoon, in solid biologically compatible material which can be resorbed during a period of the order of three weeks to three months, is mounted to slide in the tubular electrode in such manner that it can be extracted therefrom with a view to its being implanted in the endocavitary wall, by means of a thrust transmitted through the tubular conductor. This probe offers the advantage of being immobilized first by the harpoon and then, after resorption of the harpoon, by the natural formation of fibrose around the electrode.