Abstract: An engine exhaust system is disclosed which in operation is capable of substantially reducing the quantities of hydrocarbons emitted to the atmosphere during engine start-up. The system utilizes molecular sieve means, such as a high-silica zeolite, which function to adsorb hydrocarbons emitted during engine start-up, before the catalytic converter has attained its effective operating temperature. The system is designed so that, once the catalytic converter has attained an effective operating temperature, the hydrocarbons can be desorbed from the molecular sieve means and conveyed to the converter for conversion to non-toxic by-products.

Abstract: Methods and apparatus for protecting extruded metal powder green bodies (34) during firing are provided. In certain embodiments, one or more green bodies (34) are housed in a non-gas tight chamber (13) located in the hot zone (24) of a cold-wall vacuum/atmosphere furnace (10). Furnace gas, e.g., hydrogen, is supplied to the interior of the chamber (13). The resulting one-way flow out of the chamber (13) protects the green bodies (34) from the backflow of burn-out products, as well as from contaminants arising from the walls and internal components of the furnace (10). In other embodiments, green bodies (34) are housed in individual non-gas tight containers (36). The containers (36) minimize the amount of furnace gas which comes into contact with the green bodies (34) during sintering and thus minimize the level of exposure of the green bodies (34) to oxidative impurities in the furnace gas. When composed of the same material as the green bodies, the containers (36) also perform a getter function.

Abstract: A yellow color by transmitted light is produced in a high silica glass by impregnating a porous, high silica glass with a solution of chromium and zinc salts and consolidating the glass under oxidizing conditions to dope the glass with chromium and zinc oxides, the chromium being predominantly in the hexavalent state. Optionally, an aluminum salt is included in the impregnating solution. The glass has particular utility as a filter for lighting purposes.

Abstract: A process to synthetize zircon as an ultra thin coating and comprising: (A) mixing an alcoholic sol resulting from hydrolysis of a silicon alkoxide with an alcoholic solution of a chelated zirconium compound and in the presence of and with a doping agent, until a homogenous mixed sol is obtained; (B) forming a matured sol containing colloidal particles and/or the polymeric entities from the mixed sol; (C) forming a coating of the matured sol on a microporous substrate; (D) drying slowly the sol coating into a gel coating free of flaws; and (E) firing the gel coating at a temperature of 900.degree. to 1500.degree. C. to form an ultra thin zircon layer. Use of the zircon layer obtained above as an ultrafiltration membrane or as a protective coating.

Abstract: Porous sintered ceramic material having bulk analytical composition, by weight, of 74-79% alumina and the balance being silica optionally with other oxide and/or impurities naturally occurring from the batch materials, and having a phase composition, by weight, of 50-75% mullite, 23-45% corundum, 0-6% cristobalite and the balance being substantially 2-10% amorphous alumina-silica based phase. Honeycomb structure, molten metal filter and catalytic converter made from the material.

Abstract: A reduced coefficient of thermal expansion and an increased resistance to thermal shock in cordierite-containing ceramic articles is achieved by contacting such articles with water either in a liquid or gaseous state. It is particularly desirable for such treatment to reduce the coefficient of thermal expansion of the article by at least 1.times.10.sup.-7 .degree. C..sup.-1, measured between 25.degree. and 800.degree. C., during the contacting. This treatment can be used in conjunction with extruded honeycomb structures conventionally used as diesel particle filters and supports for catalysts which treat automotive exhaust gases.

Abstract: Methods and apparatus for protecting extruded metal powder green bodies (34) during firing are provided. In certain embodiments, one or more green bodies (34) are housed in a non-gas tight chamber (13) located in the hot zone (24) of a cold-wall vacuum/atmosphere furnace (10). Furnace gas, e.g., hydrogen, is supplied to the interior of the chamber (13). The resulting one-way flow out of the chamber (13) protects the green bodies (34) from the backflow of burn-out products, as well as from contaminants arising from the walls and internal components of the furnace (10). In other embodiments, green bodies (34) are housed in individual non-gas tight containers (36). The containers (36) minimize the amount of furnace gas which comes into contact with the green bodies (34) during sintering and thus minimize the level of exposure of the green bodies (34) to oxidative impurities in the furnace gas. When composed of the same material as the green bodies, the containers (36) also perform a getter function.

Abstract: A method of forming an activated carbon or graphite structure is provided by (1) forming, such as extrusion, of a plasticized mixture of: binder selected from cellulose ether and derivative thereof, starch, and mixture thereof; furfuryl alcohol and/or polyfurfuryl alcohol; and carbon, graphite, or a carbon-containing material; and (2) subjecting the formed mixture to a carbon-forming pyrolysis step. The use of furfuryl alcohol allows extrusion at ambient temperatures and provides a "reactive" solvent that provides carbon upon pyrolysis.

Abstract: An engine exhaust system disclosed which is designed to reduce hydrocarbon emissions caused by the evaporation of fuel from the fuel tank and by the inefficiency of combustion and catalytic conversion during cold engine start-up. This system utilizes molecular sieves, such as high-silica zeolites, which adsorb hydrocarbons evaporating from the fuel tank or emitted during engine start-up, before the catalytic converter has attained an effective operating temperature. This system is designed so that hydrocarbons that would otherwise be emitted to the atmosphere from the fuel tank or by passing through the converter unconverted are held within the system either for combustion in the engine or passage through the converter once it is operating efficiently.

Abstract: The present invention features a process, and a product formed by the process, wherein a catalyst device is fabricated in situ. Metal powders, metal alloy powders and mixtures thereof are introduced to a substrate, by means of a washcoat suspension. After the suspension is applied, the metals are transformed into active catalyst and catalyst support materials. The process comprises the steps of: (a) introducing to a substrate, metal powders, metal alloy powders and mixtures thereof, having particles in average diameter sizes of approximately between 5 and 50 microns; and (b) transforming in situ the particles of the metals and metal alloys and mixtures thereof, whereby the metals, metal alloys and mixtures thereof are converted into active catalyst and catalyst support materials having sub-micron average diameter sizes.

Abstract: Novel method and structure is disclosed for strengthening and mounting sloted metallic honeycomb structures by positioning rod members within the slots to prevent the slots from closing or deforming, and by utilizing the rod members to precisely engage positionable restraining inserts of an enclosing housing, so as to accurately mount the honeycomb structure within the housing.

Abstract: Porous ceramic articles are made by a method that allows the formed green body to be dried in a dielectric oven without arcing or shorting occurring while maintaining favorable physical properties. The method includes adding water insoluble cellulose and graphite to the ceramic-forming precursors as a burnout material. The method is particularly useful in forming porous cordierite articles that are extruded to form a honeycomb structure conventionally used as a particulate filter for the exhaust fluids of diesel engines. Such articles have a matrix of thin walls forming a multiplicity of open-ended cells extending from one end to another end of the honeycomb. The thin walls have a substantially smaller coefficient of thermal expansion in the direction parallel to the axes of the open-ended cells than in the direction transverse to the thin walls.

Abstract: A method of extruding a honeycomb type structures, such as filters, by flow of extrudable material (e.g. ceramic material) through a die with feed holes having smooth and gradual transition of flow cross sectional area and shape to be congruent at end of holes forming junction with intersections of criss crossing discharge slots. In a typical prior art extrusion die, the feed holes are circular in cross section throughout their length and feed into respective intersecting discharge slot portions. There is an abrupt change in cross section area and shape, from circular to cross shaped, at the entrance to the discharge slots. This construction results in flow inhibiting land portions at the entrance to the discharge slot portions. Such a construction causes bending forces or moments on these flow obstructing entrance portions of the discharge slots and also subjects them to increased abrasive wear whenever the material being extruded contains ceramic or other hard particles.

Abstract: Multi-stage catalytic systems and methods are provided for converting NO.sub.x, CO, and hydrocarbons in a mixture, to innocuous products. The systems include first and second stages, each with substrate and catalyst. The mixture is contacted with the first stage for conversion of the major portion of the NO.sub.x and a portion of the CO and hydrocarbons. The output is contacted with the second stage to for conversion of CO and hydrocarbons. In one system, the first stage catalyst consists essentially of rhodium and a zeolite; the second stage catalyst comprises a noble metal including platinum and/or palladium, and a support. The mixture has a mole ratio of reducing to oxidizing agents of at least 0.8. Low ammonia is generated. In another system, the first stage substrate is made of material capable of being heated to at least 150.degree. C. in no more than about 20 seconds, has heating means for doing same, and is at this temperature at least part of the time of contact with the mixture.

Abstract: A method of preparing a precursor or cordierite-forming particulate raw material mixture is improved upon by characterizing the talc particles utilized in the raw material mixture in accordance with a Morphology X-ray Diffraction Index or the surface area of the talc particles. Talc particles having a predetermined or desired Morphology X-ray Diffraction Index or surface area are utilized in preparing the raw material mixture. A cordierite article is produced having pores therethrough, which pores have shapes that are "blocky" or "platy" as a result of the talc morphology. "Platy" pores in the fired cordierite article result in higher Water Absorption values and an increase in coatability by high surface area washcoat and catalyst; conversely, "blocky" pores result in lower Water Absorption values and a decrease in coatability by high surface area washcoat and catalyst.

Abstract: An engine exhaust system and method of controlling hydrocarbon emissions are provided. The system and method are based on the use of two catalytic converter chambers, a first chamber containing a catalytic material and a second chamber containing catalyst as well as molecular sieves capable of adsorbing hydrocarbons during engine start-up and of having hydrocarbons desorbed therefrom when the catalysts reach an effective converting temperature. According to the invention, engine exhaust is selectively conveyed to each of the two converters in a manner such that initially produced hydrocarbon is withheld in the system by the molecular sieves in order to be recycled through the converters and brought into contact with the catalyst after an effective converting temperature has been attained.

Abstract: A monolithic ceramic structure, useful as a support for catalytic material or as a fluid filter, has a high surface area phase which consists essentially of a porous metal oxide material, at least 50% by weight of which is alumina, titania, and/or zirconia, and phosphate dispersed substantially throughout the porous metal oxide material. The presence of the phosphate stabilizes the porous metal oxide material against thermal degradation during sintering or exposure to elevated temperatures encountered in catalytic service and thereby aids in the retention of higher overall surface area in the monolithic structure.

Abstract: A body is disclosed which is at least about 90% by weight cordierite, has a mean pore size of less than about 10.0 microns, and a coefficient of thermal expansion of no greater than about 9.0.times.10.sup.-7 /.degree.C. from about 25.degree. C. to 1000.degree. C. Also disclosed is a method of fabricating the body. Raw materials are selected to form a composition consisting essentially of in percent by weight about 12 to 16 magnesium oxide, about 35 to 41 aluminum oxide, and about 43 to 53 silica. The raw materials are absent of clay and talc. The magnesium oxide is supplied by a magnesium oxide component having an average particle size of no greater than about 15.0 micrometers in diameter. The aluminum oxide is supplied by an aluminum oxide component having an average particle size of no greater than about 8.0 micrometers in diameter. The composition is capable of forming cordierite in the subsequent firing step.

Abstract: A body is disclosed which is at least about 90% by weight cordierite, and has a coefficient of thermal expansion of less than about 16.times.10.sup.-7 /.degree.C. from about 25.degree. C. to about 1000.degree. C. Also disclosed is a method of fabricating the body. Raw materials are selected to form a nominal composition consisting essentially of in percent by weight about 11.5 to about 16.5 MgO, about 33.0 to about 41.0 Al.sub.2 O.sub.3, and about 46.5 to about 53 SiO.sub.2. The raw materials can be a combination of silica and magnesium aluminate spinel, a combination of silica, magnesium aluminate spinel, and a MgO yielding component, or a combination of silica, magnesium aluminate spinel, and a Al.sub.2 O.sub.3 yielding components. The raw materials are provided absent of clay and talc. The raw materials are blended with an effective amount of vehicle and forming aids to impart plastic formability and green strength thereto form a plastic mixture.

Abstract: Novel method and apparatus for forming a substrate or honeycomb article with multi-cellular densities and/or multi-cellular geometries by positioning a pair of extrusion dies adjacent one another, such that one surrounds the other, and such that discharge slots of one die produce different cellular densities and/or geometries from that of the other. Further, an annular batch reservoir is formed between the mating surfaces of such dies so as to facilitate the flow of batch material from one die to the other, and an integral inner skin is formed between the differing cellular structures.