Ngk Insulators, Inc.

Other

Ngx Insulators, Inc.

Takuya Hiramatsu

Akira Takahashi

Fumiharu Sato

Kenji Suzuki

Shuichi Ichikawa

Kenji Morimoto

Naomi Noda

Azuma Yamamoto

Yukio Miyairi

Shinji Kawasaki

Katsuhiro Inoue

Takashi Mizutani

Yukinari Shibagaki

Junichi Suzuki

Toshihiro Tomita

Masahiko Matsukata

Yasuyuki Furuta

Fumihara Sato

There is provide a honeycomb filter which can suppress generation of cracks in plugged portions due to heat generated by burning of a PM during regeneration and comprises a honeycomb basal body including porous partition walls arranged to form a plurality of cells disposed in parallel with one another and including inflow cells and outflow cells which are formed adjacent to the inflow cells; first plugged portions with which one end of each of the inflow cells is plugged; second plugged portions with which another end of each of the outflow cells is plugged; porous collecting layers formed on the inflow-cells side surfaces of the partition walls; and end aggregate layers made of a particulate aggregate material and formed on the inflow-cells-side surfaces of the first plugged portions, and a thickness of the end aggregate layers is from 0.5 to 5 mm.

Honeycomb filter

Provided is a honeycomb structure in which as compared with partition walls of an end face side portion of all inlet of a fluid, partition walls of an end face side portion of an outlet of the fluid satisfy at least one of conditions of (1) a heat conductivity being relatively high, (2) a heat capacity being relatively large, (3) a bending strength being relatively high and (4) a porosity being relatively low. In this honeycomb structure, the melting or thermal shock breakdown of the partition walls does not easily occur, and the structure is suitably used as a DPF.

Honeycomb structure and method for manufacturing the same

A honeycomb structure includes: a periphery-ground article obtained by grinding an outer peripheral portion of a cell structurewhere honeycomb segmentsare bonded by a bonding layerat an outer wallof each of them, and an outer peripheral coat layerdisposed on an outer peripheral faceof the periphery-ground article; wherein at least one of the bonding layerand the outer peripheral coat layeris formed using honeycomb-forming slurry containing biologically soluble fibers containing a metal oxide capable of extricating a metal ion and an inorganic binder containing a colloidal oxide having modified silica sol manufactured by adding a substance containing amine or an aqueous solution of a water-soluble metalate of an amphoteric metal to silica sol. Crack generation of the outer peripheral coat layer and/or deterioration of bonding strength of the bonding layer can be inhibited.

Honeycomb structure

A honeycomb structureincludes: a periphery-ground article obtained by grinding an outer peripheral portion of a cell structurewhere a plurality of honeycomb segmentsare bonded by means of a bonding layerat an outer wallof each of them, and an outer peripheral coat layerdisposed on an outer peripheral faceof the periphery-ground article; wherein at least one of the bonding layerand the outer peripheral coat layeris formed by the use of honeycomb-forming slurry containing: biologically soluble fibers containing a metal oxide capable of extricating a metal ion, an inorganic binder containing a colloidal oxide having silica sol, and a chelate compound capable of multi-coordinating with the metal ion or an additive containing a first buffer solution or acid.

A honeycomb structure whose shape is composed of plural honeycomb segments being bonded integrally by means of a bonding material; the honeycomb structure having inner partition walls with plural first pores and defining respective cells serving as flow channels for exhaust gas, outer circumferential wall having second pores, and surrounding the inner partition walls, and inner partition walls having third pores and contacting with a processed outer circumferential surface becoming an outermost circumference through processing of an outer circumferential portion. A filling composition for the second pores and a filling composition for the third pores having the specified functions respectively are also provided.

Honeycomb segment, honeycomb structure and process for producing the same

There is disclosed a honeycomb structure having a plurality of segments and each including a plurality of cells, wherein each segment has a porous base material having the honeycomb shape, and a modified portion formed by impregnating a part of the base material with a slurry including particles smaller than the average pore diameter of the base material, followed by a heat treatment, the base material has a porosity of 30 to 80% and an average pore diameter of 5 to 40 &#x3bc;m, and the modified portion is partially formed on the section of the segment vertical (orthogonal) to the axial direction of the cells, and has a porosity which is 2 to 20% lower than that of the base material and an average pore diameter which is 0.1 to 10 &#x3bc;m smaller than that of the base material.

There is provided a honeycomb structure where a catalyst is loaded on surfaces of inner pores of the surface layer and on a surface of the surface layer; a relation between a catalyst area proportion A of the catalyst to a gap area proportion B of a gap in a cross-section of the surface layer on the inlet side is 1%&#x3c;A/B&#x3c;90%; and a relation between an average catalyst area proportion, A, from the surface to a point having a depth of one third of the thickness of the surface layer including the surface of the surface layer on the inlet side and a catalyst area proportion Ain a central portion of the surface layer is A/A&#x3e;1.5.

Honeycomb catalytic article

A silicon carbide-based porous article comprising silicon carbide particles as an aggregate, metallic silicon and an aggregate derived from siliceous inorganic particles to form pores through volume shrinkage by heat treatment, wherein the porosity is 45 to 70%, and the average pore diameter is 10 to 20 &#x3bc;m is provided. Also provided is a method for producing a silicon carbide-based porous article, comprising; adding inorganic particles to form pores through volume shrinkage by heat treatment to a raw-material mixture containing silicon carbide particles and metallic silicon, then forming into an intended shape, calcinating and firing the resultant green body, forming pores through volume shrinkage of the inorganic particles by heat treatment, and the shrunk inorganic particles being present as an aggregate in the porous article.

Porous object based on silicon carbide and process for producing the same

Provided are a silicon carbide-based porous article comprising silicon carbide particles as an aggregate, metallic silicon and an aggregate derived from organometallic compound particles to form pores through volume shrinkage due to decomposition/conversion by heat treatment; and a method for producing the silicon carbide-based porous article, comprising, adding organometallic compound particles to form pores through volume shrinkage due to decomposition/conversion by heat treatment to a raw-material mixture containing silicon carbide particles and metallic silicon, then forming into an intended shape, calcinating and/or firing the resultant green body, forming pores through volume shrinkage due to decomposition/conversion of the organometallic compound particles, and the decomposed/converted substance of the organometallic compound particles being present as an aggregate in the porous article.

A system for exhaust gas purification includes at least one adsorbent capable of adsorbing harmful substances such as hydrocarbons and the like in exhaust gas and at least one catalyst containing a catalyst component, capable of reducing said harmful substances, both provided at an in-line position of exhaust pipe of internal combustion engine. In the system, the hydrocarbons, etc. in the exhaust gas emitted during cold engine start up of internal combustion engine are adsorbed by the adsorbent and the adsorbed hydrocarbons, etc. are desorbed from the adsorbent with the temperature rise of the adsorbent caused by the heat of the exhaust gas and are burnt on the catalyst. The adsorbent contains a H type &#x3b2;-zeolite having a SiO/AlOratio of 100 or more and can maintain good adsorption capability even when exposed to an exhaust gas of 750&#xb0; C. or more form an internal combustion engine. This system for exhaust gas purification can effectively purify harmful substances in exhaust gas, particularly the hydrocarbons, etc. emitted in large amounts during cold engine start up.

System for exhaust gas purification

A highly heat-resistant and hydrothermal-resistant &bgr;-zeolite having a SiO,/Al,O,ratio of 80 or more, which is constituted by primary particles having an average particle diameter of 30 nm or more or by primary particles having such a particle size distribution that the 10% particle diameter is 20 nm or more; and an adsorbent for automobile exhaust gas purification, using said &bgr;-zeolite. The &bgr;-zeolite and the adsorbent can be produced reliably so as to have guaranteed properties.

Highly heat resistant &bgr;-zeolite and absorbent for automobile exhaust gas purification and adsorbent for automobile exhaust gas purification

The present invention provies an adsorbent which, as compared with an adsorbent comprising a zeolite (an aluminosilicate) of at least about equal Si/(Fe&plus;Al) molar ratio (Fe is substantially absent), has high heat resistance and high hydrothermal resistance and can maintain adsorption capability even when exposed to high temperatures. This adsorbent comprises a &bgr;-silicate molecular sieve containing at least Fe besides H, O and Si and, when Al is contained, containing Fe in a molar amount at least equal to that of Al.

&bgr;-zeolite molecular sieve absorbent

A system for exhaust gas purification disposed in the exhaust pipe of an internal combustion engine, which includes a zeolite as adsorbent component capable of adsorbing the hydrocarbons present in the exhaust gas emitted from the engine and a catalyst capable of reducing the harmful substances present in the exhaust gas; the system satisfies the following conditions: a/c&equals;3 to 50 cc/g, wherein a is the total volume of the pores of diameters of 10 &angst; or smaller possessed by the zeolite as measured using N,, and c is the total amount of the hydrocarbons emitted from the engine during the period of 140 seconds from the start of the engine when the engine is operated in accordance with the LA-4 mode of FTP, thereby the adsorption capacity of the zeolite used as a HC adsorbent is optimized against the amount of the HC discharged from an engine during a certain period of the cold start so as to adsorb and purify the HC effectively.

A process for synthesizing a high-silica aluminosilicate molecular sieve, includes: subjecting, to hydrothermal synthesis, a raw material containing Al, H, O and Si and, as other elements, at least Fe and having a Si/Al molar ratio of 50 or more and a Si/Fe molar ratio of 80 or less (45 or less when a high-silica aluminosilicate molecular sieve having a .beta. type zeolite structure is produced) and then subjecting the resulting material to heat treatment in an oxidizing atmosphere at 300.degree. C. or more. The above process can synthesize a high-silica zeolite low in Al content directly without dealumination operation, and can provide process simplification and a higher yield.

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Nagoya, Japan

Takuya Hiramatsu