JPS63303878A - Porous ceramic structure - Google Patents
Porous ceramic structureInfo
- Publication number
- JPS63303878A JPS63303878A JP62140442A JP14044287A JPS63303878A JP S63303878 A JPS63303878 A JP S63303878A JP 62140442 A JP62140442 A JP 62140442A JP 14044287 A JP14044287 A JP 14044287A JP S63303878 A JPS63303878 A JP S63303878A
- Authority
- JP
- Japan
- Prior art keywords
- porous ceramic
- ceramic structure
- cell
- average
- ratio
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000000919 ceramic Substances 0.000 title claims abstract description 54
- 210000004027 cell Anatomy 0.000 claims abstract description 36
- 210000003850 cellular structure Anatomy 0.000 claims abstract 6
- 238000004891 communication Methods 0.000 claims description 4
- 230000002093 peripheral effect Effects 0.000 abstract description 3
- 239000007789 gas Substances 0.000 description 15
- 229920005830 Polyurethane Foam Polymers 0.000 description 11
- 239000011496 polyurethane foam Substances 0.000 description 11
- 238000010586 diagram Methods 0.000 description 10
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 9
- 238000000746 purification Methods 0.000 description 8
- 239000003054 catalyst Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical group [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 3
- 229910052878 cordierite Inorganic materials 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 239000006260 foam Substances 0.000 description 2
- 239000000395 magnesium oxide Substances 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 2
- 239000011812 mixed powder Substances 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- CNLWCVNCHLKFHK-UHFFFAOYSA-N aluminum;lithium;dioxido(oxo)silane Chemical compound [Li+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O CNLWCVNCHLKFHK-UHFFFAOYSA-N 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000037237 body shape Effects 0.000 description 1
- 210000000170 cell membrane Anatomy 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229920000609 methyl cellulose Polymers 0.000 description 1
- 239000001923 methylcellulose Substances 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910052644 β-spodumene Inorganic materials 0.000 description 1
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は触媒担体なと、特に内燃機関排気ガス浄化用セ
ラミックス触媒担体に用いる多孔質セラミックス構造体
に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a porous ceramic structure used as a catalyst carrier, particularly as a ceramic catalyst carrier for purifying exhaust gas of an internal combustion engine.
従来、自動車等の排気ガス浄化用触媒担体として用いら
れる三次元網目状骨格を有するセラミックス構造体（以
下多孔質セラミックス構造体と称す）において、この多
孔質セラミックス構造体の断面中央部を見掛は密度が密
の多孔質体とし、また他の部分を見掛は密度が粗の多孔
質体として、例えば、自動車の排気管等に取り付けるこ
とによって、多孔質セラミックス構造体の中心を通る排
気ガスの流速を低下させることにより、流速分布を小さ
くさせて、浄化機能を向上させるという提案が特開昭５
７−５３２４２号公報によってなされている。Conventionally, in a ceramic structure having a three-dimensional network skeleton (hereinafter referred to as a porous ceramic structure) used as a catalyst carrier for purifying exhaust gas in automobiles, etc., the central part of the cross-section of the porous ceramic structure has an appearance of By using a porous body with a dense density and a porous body with an apparently coarse density in other parts, for example, by attaching it to an automobile exhaust pipe, etc., it is possible to prevent exhaust gas passing through the center of the porous ceramic structure. Japanese Patent Laid-Open No. 5 (1973) proposed that by lowering the flow velocity, the flow velocity distribution would be narrowed and the purification function would be improved.
This is disclosed in Japanese Patent No. 7-53242.
しかし、多孔質セラミックス構造体の断面中央部を見掛
は密度が密の多孔質体とすることは同時に流体が流れる
際の圧力損失を上昇させるという問題が生じていたー。However, making the porous ceramic structure appear to be a dense porous body in the center of its cross section has the problem of increasing pressure loss when fluid flows.
本発明は以上の問題点に鑑みたもので、浄化性能を向上
させるとともに、圧力損失を低（した多孔質セラミック
ス構造体を提供するものである。The present invention has been made in view of the above problems, and aims to provide a porous ceramic structure with improved purification performance and low pressure loss.
本発明の多孔質セラミックス構造体のセル構造の一部を
第１図に、またその単一のセルの模式的断面図を第２図
に示す。本発明の多孔質セラミックス構造体は内部連通
空間を有する三次元網目状の骨格を備えたセル構造をな
している。また、このセル構造の単一のセル１０は第２
図に示すように長細く、楕円体に近い多面体（１２ない
し１４面体）であり、三次元綱目状の骨格１１は多面体
の稜線を構成している。なお、内部連通空間は符号１２
で示される。A part of the cell structure of the porous ceramic structure of the present invention is shown in FIG. 1, and a schematic cross-sectional view of a single cell is shown in FIG. The porous ceramic structure of the present invention has a cell structure including a three-dimensional mesh-like skeleton having internal communication spaces. Moreover, the single cell 10 of this cell structure is
As shown in the figure, it is an elongated polyhedron close to an ellipsoid (12 to 14 faces), and the three-dimensional mesh-like skeleton 11 constitutes the ridgeline of the polyhedron. Furthermore, the internal communication space is designated by the code 12.
It is indicated by.
まず、われわれは、体格形状直径１０７ｍｍ、長さ８０
ＩＩｌＩ１１であり、それぞれ平均長径すと平均短径ａ
との比ｂ ／ ａが異なる多孔質セラミックス構造体に
より、比ｂ ／ ａと圧力損失との関係を調べた。First, we have a body shape with a diameter of 107 mm and a length of 80 mm.
IIIlI11, and the average major axis and average minor axis a
The relationship between the ratio b/a and pressure drop was investigated using porous ceramic structures with different ratios b/a.
また、圧力損失の測定は、上記セラミ・ノクス構造体の
円柱軸方向に空気を流して行った。空気は３ｎ（／ｍｉ
ｎ流し、また、空気が円柱側面から流れないようにして
測定した。測定した結果を第３図に示す。In addition, the pressure loss was measured by flowing air in the direction of the cylinder axis of the ceramic-nox structure. Air is 3n(/mi
Measurements were taken with air flowing through the cylinder, and with air not flowing from the side surface of the cylinder. The measured results are shown in Figure 3.
第３図より、われわれは、セルがほぼ球形（ｂ／ａは１
〜１．４程度）である従来の多孔質セラミック構造体に
比べ、セラミックス構造体を構成するセルの長袖Ａ−Ａ
方向の平均長径すと短軸Ｂ−Ｂ方向の平均短径ａとの比
ｂ ／ ａを１．５より太き（していくと圧力損失が低
下していくことを見出した。From Figure 3, we can see that the cell is almost spherical (b/a is 1
1.4) compared to conventional porous ceramic structures, the long-sleeved A-A of the cells that constitute the ceramic structure
It has been found that when the ratio b/a of the average major axis in the direction to the average minor axis a in the minor axis B-B direction is made thicker than 1.5, the pressure loss decreases.
そこで、本発明では、以上の結果に鑑み、セラミックス
構造体の見掛は密度を変えるのではなく、多孔質セラミ
ックス構造体の多孔質部を形成する断面中央部の平均長
径すと平均短径ａとの比ｂ／ａを外周方向に従って、比
ｂ ／ ａを中心部より大きくするという技術的手段を
採用する。Therefore, in the present invention, in view of the above results, instead of changing the apparent density of the ceramic structure, the average major axis of the central section of the cross section forming the porous part of the porous ceramic structure is added to the average minor axis a. A technical means is adopted in which the ratio b/a is made larger in the outer circumferential direction than in the center.
上記技術的手段を採用することにより、例えば、この多
孔質セラミックス構造体が自動車の排気管に取り付けら
れた際には、多孔質セラミックス構造体の中心を通る排
気ガスは、圧損が若干高いため流速が若干低下させられ
、外周部との流速分布が小さくなる。そのため、浄化性
能を向上させることができ、かつ、多孔質セラミックス
構造体を構成するセルが楕円形状であるので、従来と比
べて圧力損失を低下させることができる。By adopting the above technical means, for example, when this porous ceramic structure is installed in the exhaust pipe of a car, the exhaust gas passing through the center of the porous ceramic structure has a slightly high flow rate due to the slightly high pressure drop. is slightly lowered, and the flow velocity distribution with respect to the outer circumference becomes smaller. Therefore, purification performance can be improved, and since the cells constituting the porous ceramic structure have an elliptical shape, pressure loss can be reduced compared to the conventional method.
圧力損失を低下させることができるのは、円柱状のセラ
ミックス構造体の中をガスが直線的に進むと考えた場合
、セルが楕円形状であればあるほど、ガス粒子はガスの
流れに対して直角なセルの骨格によって乱される確率が
小さくなる。つまり、圧力損失がガスに働く慣性力と粘
性力とにより生じていることを考えれば、セルが楕円形
状であればあるほどガスがセルの骨格と衝突する回数が
城るので、ガスの乱れが少なくなることにより、慣性力
が減じ圧力損失が低下するのである。The pressure drop can be reduced by assuming that gas travels linearly through a cylindrical ceramic structure, and the more elliptical the cell is, the more the gas particles will be able to resist the gas flow. The probability of being disturbed by the orthogonal cell skeleton is reduced. In other words, considering that pressure loss is caused by inertial force and viscous force acting on the gas, the more elliptical the cell, the more likely the gas will collide with the cell skeleton, which will reduce the turbulence of the gas. By decreasing the amount, the inertial force is reduced and the pressure loss is reduced.
本発明の多孔質セラミックス構造体２０として、体格断
面形状、長径１４６Ｍ、短径７５ｍｍ、および長さ１４
３鵬の楕円柱状のものを用意し、第４図にその斜視図を
示した。ここで、多孔質部２５においてのセラミックス
の見掛は密度は０．２〜０゜３ｇ／ａａである。また、
セラミックス構造体２０の最外周には補強層２８として
緻密なセラミックス層が厚さ２−で設けられている。多
孔質部２５は第２図に示すような長細いセル構造をもっ
た多孔質セラミックスで構成され、平均長径すと平均短
径ａとの比ｂ ／ ａは、第５図の如く、多孔質部２５
の中心部から外周方向に従い、約２．７より連続的に太
き（なり、多孔質部２５の最外周では約４となっている
。The porous ceramic structure 20 of the present invention has a body cross-sectional shape, a major axis of 146 mm, a minor axis of 75 mm, and a length of 14 mm.
A three-dimensional elliptical cylinder was prepared, and its perspective view is shown in Fig. 4. Here, the apparent density of the ceramic in the porous portion 25 is 0.2 to 0.3 g/aa. Also,
A dense ceramic layer with a thickness of 2-2 is provided as a reinforcing layer 28 on the outermost periphery of the ceramic structure 20. The porous portion 25 is made of porous ceramic having an elongated cell structure as shown in FIG. 2, and the ratio b/a of the average major axis to the average minor axis a is as shown in FIG. Part 25
From the center to the outer circumferential direction, the thickness increases continuously from about 2.7 mm, and at the outermost circumference of the porous portion 25, the thickness increases to about 4 mm.
次に本発明の多孔質セラミックス構造体の製造方法につ
いて第６図を用いて説明する。Next, the method for manufacturing the porous ceramic structure of the present invention will be explained using FIG. 6.
即ち、従来の方法によってポリウレタンフォームを発泡
させた後、気泡膜を除去して連通化したセル構造を有す
る樹脂発泡体であるポリウレタンフォーム３０を用意す
る。その後、第６図（ａ）の如く、一方に凸状部３５ａ
、３６ａが形成された引張り治具３５と３６の中間に、
ポリウレタンフォームを設ける。そして、引張り治具３
５，３６の凸状部３５ａ、３６ａに、ウレタンフオーム
と十分強固に接着可能であり、かつ１００°Ｃ以下でも
固着可能な接着剤３８を塗布し、第６図（ｂ）の如く、
引張り治具３５，３６の凸状部３５ａ、３６ａをポリウ
レタンフォーム３０の両端に押し付け、その状態におい
て凸状部３５ａ、３６ａに付着させた接着剤を硬化させ
る。その後、第６図（Ｃ）の如く、引張り治具３５．３
６を両方向に引き伸ばすことによって、ポリウレタンフ
ォーム３０の中央部の伸び率を小さく、外周部の伸び率
を大きくすることができる。そして、この状態のままで
約１００〜１５０°Ｃの温度を有する炉の中で約３０〜
９０分間保持することにより、引き伸ばされたセル構造
をもつポリウレタンフォームを得ることができる。また
、引張り治具３５．３６からのポリウレタンフォームの
取り出しは、ポリウレタンフォームの両端をナイフ等に
より切断することにより行う。That is, after foaming polyurethane foam using a conventional method, the cell membrane is removed to prepare polyurethane foam 30, which is a resin foam having a connected cell structure. After that, as shown in FIG. 6(a), a convex portion 35a is formed on one side.
, 36a are formed between the tension jigs 35 and 36,
Provide polyurethane foam. And tension jig 3
An adhesive 38 that can be bonded sufficiently firmly to the urethane foam and can be bonded even at 100° C. or lower is applied to the convex portions 35a and 36a of 5 and 36, as shown in FIG. 6(b).
The convex portions 35a, 36a of the tensioning jigs 35, 36 are pressed against both ends of the polyurethane foam 30, and in this state, the adhesive attached to the convex portions 35a, 36a is cured. After that, as shown in FIG. 6(C), the tension jig 35.3
By stretching 6 in both directions, the elongation rate of the central portion of the polyurethane foam 30 can be reduced, and the elongation rate of the outer peripheral portion can be increased. Then, in this state, it is placed in a furnace with a temperature of about 100 to 150 °C for about 30 to
By holding for 90 minutes, a polyurethane foam with an elongated cell structure can be obtained. Further, the polyurethane foam is removed from the tensioning jig 35, 36 by cutting both ends of the polyurethane foam with a knife or the like.
こうして得られたポリウレタンフォームを断面形状が短
径７５ｍｍ、長径１４６田の断面形状で、長さ約１４３
ｍｍの楕円柱状に加工した。なお、セルの長袖の方向は
円柱軸と一致させた。The thus obtained polyurethane foam has a cross-sectional shape with a minor axis of 75 mm and a major axis of 146 mm, and a length of approximately 143 mm.
It was processed into an elliptical cylinder shape of mm. Note that the direction of the long sleeve of the cell was made to coincide with the cylinder axis.
次にこのポリウレタンフォームにセラミックススラリー
を含浸させ、エアガンや遠心分離装置を用いて余分なス
ラリーを除去した後、５０〜８０°Ｃで乾燥させ、さら
に、上記のセラミックススラリーよりも高粘度のセラミ
ックススラリーをポリウレタンフォームの最外周に塗布
し、乾燥させた。Next, this polyurethane foam is impregnated with ceramic slurry, excess slurry is removed using an air gun or centrifugal separator, and then dried at 50 to 80°C. was applied to the outermost periphery of the polyurethane foam and allowed to dry.
そして、１０００〜１３００°Ｃで約７時間焼成するこ
とによって三次元綱目状構造を有する多孔質セラミック
ス構造体を得た。なお、ここで、スラリーの原料は、焼
成によりコーディエライト組織となる酸化マグネシウム
（ＭｇＯ）、アルミナ（Ａ ｊ！ Ｚ Ｏ’ｓ ） 、
シリカ（ＳｉＯｔ）を含む混合粉末、あるいは上記混合
粉末を加熱してコーディエライト系セラミックスとし、
これを粉末化した合成コーディエライト粉末に対して、
メチルセルロース、ポリビニルアルコール等のバインダ
５〜１０ｗｔ％、界面活性剤、分散剤等を２〜３ｗｔ％
、水５０〜１００ｗｔ％を加え撹拌混合したものである
。Then, by firing at 1000 to 1300°C for about 7 hours, a porous ceramic structure having a three-dimensional mesh structure was obtained. Note that here, the raw materials for the slurry are magnesium oxide (MgO), alumina (A j! Z O's), which becomes a cordierite structure by firing.
Mixed powder containing silica (SiOt) or the above mixed powder is heated to produce cordierite ceramics,
For synthetic cordierite powder made by powdering this,
5 to 10 wt% of binder such as methylcellulose or polyvinyl alcohol, 2 to 3 wt% of surfactant, dispersant, etc.
, 50 to 100 wt % of water was added and mixed with stirring.
更に、上記の製造方法によって得られた多孔質セラミッ
クス構造体の骨格表面に比表面積が１０ｒｒｆ／ｇ以上
の例えばｒ−ＡｌｚＯ８をフオーム状セラミックス１２
当り１００〜２００ｇ付着させ、その後、白金、ロジウ
ム、ルテニウム等の貴金属を付着させることにより、最
外周に補強層が設けられた多孔質セラミックス構造体で
ある触媒浄化担体とした。Further, on the skeletal surface of the porous ceramic structure obtained by the above manufacturing method, for example, r-AlzO8 having a specific surface area of 10 rrf/g or more is applied to the foamed ceramic 12.
By depositing 100 to 200 g per portion and then depositing noble metals such as platinum, rhodium, and ruthenium, a catalyst purification carrier, which is a porous ceramic structure provided with a reinforcing layer on the outermost periphery, was obtained.
ここで、比較例１として平均短径ａが約５−１平均長径
すと平均短径ａとの比ｂ ／ ａが約１．３であるセル
構造（はぼ球形な従来セル）で、多孔質郡全体をセラミ
ックス密度０．２ｇ／ｃｃとしたものを、また比較例２
としては、セル径が約１．３躯である従来のモノリス担
体を用意した。Here, as Comparative Example 1, a cell structure (conventional spherical cell) in which the average minor axis a is approximately 5-1, the average major axis and the average minor axis a, b/a, is approximately 1.3 is used. Comparative Example 2 also had a ceramic density of 0.2 g/cc for the entire material.
A conventional monolith carrier having a cell diameter of approximately 1.3 cells was prepared.
比較実験を第７図を用いて述べる。まず、各々の多孔質
セラミックス構造体を体積約１３００ ｃｃ、断面形状
が短径７５ｍｍ、長径１４６ｍｍの楕円形状、長さを１
４３＋＋＋ｍに成形する。この各多孔質セラミックス構
造体を排気管６０中にセラミックス構造体の保持用ネッ
ト６５を介して設置する。A comparative experiment will be described using FIG. First, each porous ceramic structure has a volume of approximately 1300 cc, a cross-sectional shape of an ellipse with a minor axis of 75 mm, a major axis of 146 mm, and a length of 1.
Shape to 43+++m. Each porous ceramic structure is installed in the exhaust pipe 60 via a net 65 for holding the ceramic structure.
その後、２０００ ｃｃの内燃機関による２８００ｒｐ
ｍ＋ −３６０ｒＩｍ）Ｉｇの条件下において、排気ガ
スを冷却させることにより、排気ガス温度と窒素酸化物
（ＮＯｘ）の浄化率との関係を調べた。その結果を第８
図に示した。第８図より明らかなように、本発明のもの
が、比較例１、比較例２と比べて低温の排気ガス温度に
おいても、窒素酸化物の浄化率を維持することができた
。また比較例１と比較すると、浄化率は大幅に向上した
。Then 2800rpm by 2000cc internal combustion engine
The relationship between the exhaust gas temperature and the nitrogen oxide (NOx) purification rate was investigated by cooling the exhaust gas under the condition of m+ -360rIm)Ig. The results are shown in the 8th section.
Shown in the figure. As is clear from FIG. 8, the product of the present invention was able to maintain the purification rate of nitrogen oxides even at a lower exhaust gas temperature than Comparative Examples 1 and 2. Moreover, when compared with Comparative Example 1, the purification rate was significantly improved.
これは、本発明よりなる多孔質セラミックス構造体にお
いては、触媒担体全体が有効に利用されていることを示
している。This shows that in the porous ceramic structure of the present invention, the entire catalyst carrier is effectively utilized.
また、常温の空気を３ｒ［／ｍｉｎ流して圧力損失を測
定した結果、比較例１が２２ｍｍＨｇであるのに対し、
本発明例は１３ｍｍＨｇと圧力損失は大幅に低減するこ
とができた。In addition, as a result of measuring the pressure loss by flowing room temperature air at 3 r[/min], the pressure loss was 22 mmHg in Comparative Example 1, whereas
In the example of the present invention, the pressure loss was significantly reduced to 13 mmHg.
前記実施例では、断面形状が楕円形状のものについて行
ったが、もちろん他の形状でも同様の結果が得られ、例
えば円柱状、四角形状、六角形状でもよい。In the above embodiments, the cross-sectional shape was elliptical, but of course similar results can be obtained with other shapes, such as cylindrical, square, and hexagonal shapes.
前記実施例では、多孔質セラミックス構造体の材質とし
てコージェライトを用いたが、本発明ではこれに限られ
るものではなく、他にアルミナ、ムライト、β−スポジ
ューメン、窒化珪素、炭化珪素等を用いることができる
。In the above embodiment, cordierite was used as the material for the porous ceramic structure, but the present invention is not limited to this, and other materials such as alumina, mullite, β-spodumene, silicon nitride, and silicon carbide may also be used. Can be done.
前記実施例では、多孔質部のセル構造の平均短径ａと平
均長径すとの比ｂ ／ ａを多孔質部の中心部で最も小
とし、外周方向に従い連続的に大としたが、第９図に示
す如く、比ｂ ／ ａを段階状に変化させても同様の効
果が得られる。In the above example, the ratio b/a of the average minor axis a to the average major axis of the cell structure of the porous portion was the smallest at the center of the porous portion and increased continuously in the outer circumferential direction. As shown in FIG. 9, the same effect can be obtained by changing the ratio b/a stepwise.
前記実施例では、多孔質セラミックス構造体を内燃機関
の排気ガス浄化用触媒担体として用いたが、ディーゼル
エンジンから排出されるディーゼルパティキュレートの
捕集体としても同様の効果を得ることができる。In the above embodiment, the porous ceramic structure was used as a catalyst carrier for purifying exhaust gas of an internal combustion engine, but the same effect can be obtained by using it as a collector for diesel particulates discharged from a diesel engine.
（発明の効果〕
本発明である多孔質セラミックス構造体の多孔質を構成
するセル構造を、セルの平均短径ａと平均長径すとの比
ｂ ／ ａを１．５以上とし、かつ多孔質部の中心部で
はセルの平均短径ａと平均長径すとの比ｂ ／ ａを小
とし、外周部に従い、中心部より比ｂ ／ ａを大とす
ることにより、多孔質セラミックス構造体を流れるガス
の圧力損失を停止させ、浄化率を高めることができた。(Effect of the invention) The cell structure constituting the porosity of the porous ceramic structure of the present invention has a ratio b/a of the average short axis a to the average long axis of the cells of 1.5 or more, and is porous. At the center of the cell, the ratio b/a of the average short axis a to the average long axis of the cell is made small, and at the outer periphery, the ratio b/a is made larger than the center, so that the flow through the porous ceramic structure is reduced. We were able to stop the gas pressure loss and increase the purification rate.
第１図は本発明の多孔質セラミックス構造体のセル構造
組織を示す模式図、第２図は第１図のセル構造の一部を
拡大して示す模式図、第３図は平均長径すと平均短径ａ
との比ｂ ／ ａと圧力損失との関係を示す特性図、第
４図は本発明の多孔質セラミックス構造体の一例を示す
模式図、第５図は第４図の多孔質セラミックス構造体に
おける比ｂ／ａの分布を示す特性図、第６図は本発明の
多孔質セラミックス構造体の製造方法の一例を示す模式
図、第７図は多孔質セラミックス構造体の実験方法を示
す模式図、第８図は多孔質セラミックス構造体の特性を
示す特性図、第９図は他の実施例を示す特性図である。
１０・・・セル、１１・・・骨格、１２・・・内部連通
空間。Fig. 1 is a schematic diagram showing the cell structure of the porous ceramic structure of the present invention, Fig. 2 is a schematic diagram showing an enlarged part of the cell structure in Fig. 1, and Fig. 3 is a schematic diagram showing the cell structure of the porous ceramic structure of the invention. Average minor axis a
Fig. 4 is a schematic diagram showing an example of the porous ceramic structure of the present invention, and Fig. 5 is a characteristic diagram showing the relationship between the ratio b/a and pressure loss. A characteristic diagram showing the distribution of the ratio b/a, FIG. 6 is a schematic diagram showing an example of the method for producing the porous ceramic structure of the present invention, and FIG. 7 is a schematic diagram showing the experimental method for the porous ceramic structure. FIG. 8 is a characteristic diagram showing the characteristics of the porous ceramic structure, and FIG. 9 is a characteristic diagram showing another example. 10... Cell, 11... Skeleton, 12... Internal communication space.
Claims (2)
セル構造をなした多孔質セラミックス構造体において、 前記セル構造の個々のセルが長細い形状を有しており、
前記セルの平均長径ｂと平均短径ａとの比ｂ／ａが、前
記構造体の断面中央部よりも外周部の方が大であるよう
に構成されていることを特徴とする多孔質セラミックス
構造体。(1) In a porous ceramic structure having a cellular structure and having a three-dimensional mesh-like skeleton having an internal communication space, each cell of the cellular structure has an elongated shape,
A porous ceramic characterized in that the ratio b/a of the average major axis b to the average minor axis a of the cells is larger at the outer periphery than at the center of the cross section of the structure. Structure.
が、少なくとも１．５以上であることを特徴とする特許
請求の範囲第１項記載の多孔質セラミックス構造体。(2) Ratio b/a of the average major axis b and average minor axis a of the cell
2. The porous ceramic structure according to claim 1, wherein the porous ceramic structure is at least 1.5.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62140442A JPS63303878A (en) | 1987-06-04 | 1987-06-04 | Porous ceramic structure |
| EP87306496A EP0254557A3 (en) | 1986-07-22 | 1987-07-22 | A porous structure and a process for production thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62140442A JPS63303878A (en) | 1987-06-04 | 1987-06-04 | Porous ceramic structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63303878A true JPS63303878A (en) | 1988-12-12 |
Family
ID=15268735
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62140442A Pending JPS63303878A (en) | 1986-07-22 | 1987-06-04 | Porous ceramic structure |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63303878A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007126341A (en) * | 2005-11-07 | 2007-05-24 | Toshiba Corp | Anisotropic porous material |
-
1987
- 1987-06-04 JP JP62140442A patent/JPS63303878A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007126341A (en) * | 2005-11-07 | 2007-05-24 | Toshiba Corp | Anisotropic porous material |
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