Abstract: The subject of the invention is a catalyst support made of a porous inorganic material, for the treatment of exhaust gases, having a honeycomb structure, one of the faces of the structure serving for the intake of the exhaust gases to be treated and the other face serving for the discharge of the treated exhaust gases, which structure comprises, between these intake and discharge faces, an array of adjacent ducts or channels of mutually parallel axes separated by porous walls, said support being coated on at least part of its internal surface with at least one vinylpyrrolidone polymer or copolymer.

Abstract: The invention relates to a process for firing a porous ceramic structure of the honeycomb type on a firing setter, said structure comprising a plurality of longitudinal through-channels terminating in two ends of the structure, the end bearing on the setter having a maximum width LS before firing, in a longitudinal sectional plane passing through the principal axis of the structure, said process being characterized in that the setter has, in said longitudinal sectional plane: a first level corresponding to a first face of the setter serving as bearing surface for the structure to be fired, said level having a maximum width L1; a second level, spaced away from said first face of the setter by a thickness E1-2, said second level having a maximum width L2; the width L1 being equal to or greater than LS; and the width L2 being less than L1, and also to the setter as described above.

Abstract: The invention relates to a structure of the honeycomb type, comprising a porous ceramic material based on aluminum titanate, the thermal expansion coefficient of which between 20 and 1000° C. is less than 2.5×10?6/° C., said structure also having a porosity greater than 10% and a pore size centered between 5 and 60 microns, said structure being characterized in that the composition of the porous ceramic material comprises, by weight, from 30 to 60% of Al2O3, from 30 to 60% of TiO2, from 1 to 20% of SiO2, less than 10% of MgO, less than 0.5% of oxides from the group Na2O, K2O, SrO, CaO, Fe2O3, BaO and rare earth oxides, said structure also being characterized in that it has a permanent linear change on reheating, after heating at 1500° C., of less than ±0.3%. The invention also relates to a catalytic filter or support obtained from such a structure.

Abstract: The invention relates to a mixture of fused grains having the following chemical composition, in weight percentages on the basis of the oxides: less than 55% of Al2O3; more than 35% and less than 80% of TiO2; more than 1% and less than 20% of MgO; more than 0.7% and less than 20% of ZrO2; and less than 20% of SiO2, said fused grains also corresponding to the following composition, in molar percentages, on the basis of the single oxides Al2O3, TiO2, MgO, ZrO2: 90<2a+3m<110, 100+a<3t<210?a with a+t+m+zr=100, in which: a is the molar percentage of Al2O3; t is the molar percentage of TiO2; m is the molar percentage of MgO; and zr is the molar percentage of ZrO2. The invention also relates to a ceramic product obtained from such fused grains.

Abstract: The invention relates to a gas filter structure for filtering particulate-laden gases, of the honeycomb type and comprising an assembly of longitudinal adjacent channels of mutually parallel axes separated by porous filtering walls, in which: each outlet channel has a wall common to six inlet walls, each common wall constituting a side of said outlet channel; each outlet channel consists of six sides of approximately identical width a, so as to form a channel of approximately hexagonal and regular cross section; at least two adjacent sides of each inlet channel have a different width; at least two inlet channels sharing a wall with one and the same outlet channel share between them a common wall of width b; and in which the ratio of the widths b/a is equal to 1.

Abstract: The invention relates to an assembly consisting of a device for detecting radial cracks in a particulate filter of the honeycomb type, of which the filtering part is made up of a porous inorganic material, said particulate filter comprising a single monolithic element or being obtained by combining a plurality of monolithic elements, the device being characterized in that it comprises an electrically conducting material arranged in the form of a strip or of a wire on at least one longitudinal part of the filter, secured to a monolithic element and/or to the coating cement or the jointing cement, and having an electrical conductivity greater than that of the material that makes up that part of the filter to which it is secured, and a strength less than or equal to that of the material that constitutes that part of the filter to which it is secured, and means of measuring the conductivity or the electrical resistance of the strip or wire of electrically conducting material.

Abstract: A device for the purification of a polluted gas, for example an exhaust gas from a diesel or gasoline engine, comprising, in combination: A honeycomb structure, comprising at least one porous electron-conductive material forming the walls (1) of said structure and an electrochemical system for treating said gas, comprising a layer (7) of an ionically conductive and electronically insulating material D, a reduction catalyst A (9) for reducing the polluting species of the NOx type and an oxidation catalyst B (4) for oxidizing the polluting species of the soot, hydrocarbon HC, CO or H2 type, said electrochemical system being configured in the form of an electrode W and a counterelectrode CE; and means for applying a voltage or a current between said electrode W and said counterelectrode CE.

Abstract: The invention relates to a gas filter structure for filtering particulate-laden gases, of the honeycomb type and comprising an assembly of longitudinal adjacent channels of mutually parallel axes separated by porous filtering walls, in which: each outlet channel has a wall common to six inlet walls, each common wall constituting a side of said outlet channel; each outlet channel consists of six sides of approximately identical width a, so as to form a channel of approximately hexagonal and regular cross section; at least two adjacent sides of each inlet channel have a different width; at least two inlet channels sharing a wall with one and the same outlet channel share between them a common wall of width b; and in which the ratio of the widths b/a is greater than 0 but less than 1.

Abstract: The invention relates to a process for fabrication of a porous refractory ceramic product made from SiC, by heat treatment and sintering at high temperature, starting from a fraction of fine particles of SiC and from a fraction of larger-sized particles of SiC, said process being characterized in that, in a step preliminary to the heat treatment and to the sintering at high temperature, the finest particles of SiC are agglomerated then, in a second step, the granules thus obtained are added to the SiC powder with particles of larger size. The invention also relates to a porous body made from recrystallized SiC in an essentially ? form, in particular a particulate filter for automobile application, obtained by such a process.

Abstract: Structure for filtering particulate-laden gases, of the honeycomb type, which is characterized in that the material based on silicon carbide constituting its walls has an open porosity of between 30 and 53%, a median pore diameter between 9 and 20 ?m, an average number of open pores on the surface of the walls, the equivalent opening area of which is between 20 and 310 ?m2, is greater than 300 per mm2 of wall and a ratio of the total opening area of said open pores to said surface of the walls between 15 and 30%.

Abstract: The invention relates to a method of obtaining a homogeneous filtering structure for a catalytic application, which can be used as a particulate filter in an internal combustion engine exhaust line, said structure comprising a plurality of honeycomb filter elements in which a homogeneity criterion characteristic of the constituent support material of said elements, in the absence of a catalytic coating, is determined in a prior step, and then the elements making up the structure are selected by means of this homogeneity criterion so as to obtain a structure suitable for homogeneous deposition, within an element and from one element to another, of a catalyst for treating the pollutants in gas phase. The invention also relates to the homogeneous filtration structure obtained by said method.

Abstract: The invention relates to a method for measuring the uniformity of the deposit of soot in a particulate filter, comprising the steps consisting in measuring, simultaneously or in succession, the respective characteristic quantities of at least two gas streams each having passed through a different longitudinal portion of said filter, and then in comparing the characteristic quantities thus measured. It also relates to a method for controlling the regeneration of a particulate filter, comprising the steps consisting in measuring the uniformity of the soot deposit in said filter and in adjusting the parameters of said regeneration according to the uniformity value obtained.

Abstract: The invention relates to a honeycomb monolithic element for the filtration of particles, characterized in that the peripheral channels forming part of the outer wall of said element are configured to help in the formation of an outer wall whose inner face is substantially flat over the whole length of the element and in that said flat wall also has an increased thickness at the corners, so that, on a cross section, the ratio R of the thickness Ec of the wall, measured along the bisecting line of the angle at a corner of the element, over the minimal thickness Emin of said wall is greater than 1.5.