Ngk Insulators, Inc.

Hideaki Nishi

Yasushi Noguchi

Hiroyuki Suenobu

Yoshimasa Kondo

Kazuhiko Kumazawa

Eiji Ito

A porous honeycomb structure includes: a plurality of partition walls containing cordierite as a main component and constituted of a porous ceramic having a porosity of 55 to 75% and an average pore diameter of 15 to 35 &#x3bc;m, wherein the partition walls have a pore distribution represented by the following condition formula (1):&#x3e;0.3&#xd7;/100+0.91,&#x2003;&#x2003;(1) The porous honeycomb structure is capable of effectively achieving raising of a trapping efficiency of soot or the like, lowering of a pressure loss, improving a purifying performance by effective use of a catalyst, and lengthening a trapping time, and is additionally capable of improving a dissolved loss limit at the time of filter regeneration, and an isostatic strength.

Porous honeycomb structure

There is disclosed a honeycomb ceramics filter, wherein an average pore diameter X (&#x3bc;m) and partition wall thickness W (&#x3bc;m) of the filter satisfy a relation of 10&#x2267;W/X. According to this filter, while a predetermined trapping efficiency is maintained, a pressure loss can be prevented from increasing to be not less than a predetermined pressure loss even with use for a long period.

Honeycomb ceramics filter

A ceramics structure body having chemical composition of 42 to 56 wt % of SiO , 30 to 45 wt % of Al O and 12 to 16 wt % of MgO, crystalline phase mainly composed of cordierite, a porosity of 55 to 65%, an average pore size of 15 to 30 &mgr;m; and the total area of pores exposed on surfaces of partition walls constituting the honeycomb ceramics structure body being 35% or more of the total area of partition wall surfaces. Fifteen to 25 wt % of graphite and 5 to 15 wt % of a synthetic resin are added as a pore forming agent to a cordierite-forming raw material; the resultant is kneaded and molded into a honeycomb shape; and the resultant is dried and fired to produce above-mentioned honeycomb ceramics structure body. According to this honeycomb ceramics structure body, a low pressure loss and a high collection efficiency can be attained.

Honeycomb ceramics structure body and method for producing the same

There is a method of manufacturing a ceramic structure in which a ceramics raw material, a prefoamed resin foam, and a forming aid if needed are mixed together to prepare a mixture, then the mixture is formed into a formed body, and subsequently the formed body is fired to obtain a porous ceramic structure. According to the manufacturing method, a ceramic structure having a high porosity can be obtained, without using a large amount of flammable powder.

Method of manufacturing ceramic structure

A porous honeycomb filter made from a material containing cordierite, of which pore distribution is controlled, as the primary crystalline phase. The pore distribution is such that the volume of a pore with a diameter of below 10 &mgr;m is 15% or less of the total pore volume, the volume of a pore with a diameter of 10 to 50 &mgr;m is 75% or more of the total pore volume, and the volume of a pore with a diameter of above 50 &mgr;m is 10% or less of the total pore volume. This porous honeycomb filter has a high collection efficiency for fine particles (particulates), or the like, and can prevent increase in pressure loss due to the plugging of pores, and particularly can exploit the characteristics thereof for diesel engines that use recent high-pressure fuel injection, common rails, etc.

Porous honeycomb filter and manufacturing method thereof

A method of producing a ceramic body having a construction such that cells are plugged alternately at both end faces of a ceramic honeycomb structural body by filling a plugging slurry into predetermined cells at both end faces of a ceramic honeycomb formed body, having the steps of: filling a plugging material for mask into the cells to be opened at one end face of the ceramic honeycomb formed body; immersing the end face, to which the plugging material for mask is filled, into a plugging slurry; and drying and sintering the ceramic honeycomb formed body while the plugging material for mask is removed during a drying step or a sintering step.

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Toyoake, Japan

Hideaki Nishi