JP3833761B2 - EXHAUST GAS PURIFYING CATALYST CONVERTER, PROCESS FOR PRODUCING THE SAME, AND HEAT-RESISTANT INORGANIC FIBER MAT FOR USE IN EXHAUST GAS PURIFYING CATALYST CONVERTER - Google Patents

EXHAUST GAS PURIFYING CATALYST CONVERTER, PROCESS FOR PRODUCING THE SAME, AND HEAT-RESISTANT INORGANIC FIBER MAT FOR USE IN EXHAUST GAS PURIFYING CATALYST CONVERTER Download PDF

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JP3833761B2
JP3833761B2 JP00428797A JP428797A JP3833761B2 JP 3833761 B2 JP3833761 B2 JP 3833761B2 JP 00428797 A JP00428797 A JP 00428797A JP 428797 A JP428797 A JP 428797A JP 3833761 B2 JP3833761 B2 JP 3833761B2
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heat
exhaust gas
resistant inorganic
fiber mat
inorganic fiber
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JPH10196355A (en
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敬一 阪下
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Ibiden Co Ltd
Toyota Motor Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28—Construction of catalytic reactors
    • F01N3/2839—Arrangements for mounting catalyst support in housing, e.g. with means for compensating thermal expansion or vibration
    • F01N3/2853—Arrangements for mounting catalyst support in housing, e.g. with means for compensating thermal expansion or vibration using mats or gaskets between catalyst body and housing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2450/00—Methods or apparatus for fitting, inserting or repairing different elements
    • F01N2450/02—Fitting monolithic blocks into the housing

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  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Gasket Seals (AREA)

Description

【０００１】
【発明の属する技術分野】
この発明は、主として車両の排気系において、エキゾーストパイプの途中やエキゾーストマニホールドに設けて排気ガスの浄化をはかる、排気ガス浄化用コンバータ、特に触媒保持体と分割型シェルとの間に結晶質アルミナファイバの耐熱無機繊維マットによる保持シール層を介在させた排気ガス浄化用触媒コンバータおよびその製造方法に関する。
【０００２】
【従来の技術】
従来、排気ガス浄化用触媒コンバータとしては、白金等の触媒が保持された触媒保持体とこの触媒保持体の外側を覆う筒状の金属シェルとの間に、保持シール層を設けた構造のものが知られている。なお、触媒保持体には、断面がハニカム状のコージェライト担体が一般に用いられている。
【０００３】
また、保持シール層は、未膨張バーミキュライトとセラミックファイバ等との混合物で主として構成されてきたが、近年のエンジンの高性能化に伴って排気ガスの温度が高くなって、保持シール層に対する耐熱性の強化が求められているのに反して、バーミキュライトの耐熱温度がそれほど高くないことから、結晶質アルミナファイバ等の耐熱無機繊維のみからなる保持シール層の適用が試みられている。
【０００４】
そして、この種の排気ガス浄化用触媒コンバータは、触媒保持体に、保持シール層となる耐熱無機繊維マットを巻き付けてから、この触媒保持体を２分割された分割型シェルで挟んで組み付ける、いわゆるクラムシェル方式にて製造するのが、一般的である。
【０００５】
しかしながら、耐熱無機繊維による耐熱無機繊維マットを触媒保持体に巻き付けて、分割型シェルで挟み込んで組み立てる際、耐熱無機繊維マットが分割型シェルの合わせ目に噛み込まれたり、分割型シェルと耐熱無機繊維マットとの滑りが悪いために、耐熱無機繊維マットが破損する、等の問題が発生していた。
【０００６】
これら問題を解決するために、密封したフィルムで耐熱無機繊維マットを、いわゆる真空パックする方法が、例えば特開昭５７−１４６９５４号公報に、提案されている。ここで、耐熱無機繊維マットは真空パックによって減厚されるが、この減厚は真空パック内外の差圧を利用して行われることから、大気圧以上の圧縮力を与えることはできない。そのために、真空パックされて分割型シェル内に組み込まれた耐熱無機繊維マットの嵩密度は、真空パック前の耐熱無機繊維マットに比較してそれほど高くはならない。
【０００７】
【発明が解決しようとする課題】
ところで、排気ガス浄化用触媒コンバータの保持シール層は、触媒保持体を分割型シェル内に保持し、自動車の走行中の振動等により触媒保持体が、その外側の分割型シェルに当たって破損するのを防ぎ、さらに分割型シェルと触媒保持体との間から排気ガスがリークするのを防ぐために用いられている。
【０００８】
すなわち、分割型シェルに耐熱無機繊維マットを組み込んで得られる保持シール層は、例えば０．２ｇ／ｃｍ3 以上、好ましくは０．３ｇ／ｃｍ3 以上の嵩密度が必要とされるが、上記の真空パックによる手法では、圧縮力が小さいために、ここまでの嵩密度を得ることが難しい。なお、真空パック前の耐熱無機繊維マットの嵩密度を高くすることも考えられるが、嵩密度を高くすると、真空パックによって所定の減厚が達成されずに、耐熱無機繊維マットが分割型シェルの合わせ目に噛み込み易くなるため、採用できない。
【０００９】
そこで、この発明は、保持シール層として機能するに十分の嵩密度を保持シール層に付与した排気ガス浄化用触媒コンバーターを、上記した不利をまねくことなしに、提供しようとするものである。
【００１０】
【課題を解決するための手段】
この発明は、触媒保持体と、この触媒保持体の外側を覆う金属製の分割型シェルとの間に、主に耐熱無機繊維から構成された保持シール層を設けた排気ガス浄化用触媒コンバータにおいて、上記保持シール層は、分割型シェルの合わせ目近傍部分における嵩密度に比して、それ以外の部分の嵩密度を大きくしたことを特徴とする排気ガス浄化用触媒コンバータである。
【００１１】
ここで、保持シール層の分割型シェルの合わせ目近傍部分における嵩密度が０．１６〜０．３０ｇ／ｃｍ3 であること、保持シール層の分割型シェルの合わせ目近傍以外の部分における嵩密度が０．２５〜０．５０ｇ／ｃｍ3 であること、そして保持シール層を構成する結晶質アルミナファイバは、平均繊維径が２〜６μm およびアルミナ含有率が６０wt％以上であること、が実施に当たり有利である。
【００１２】
また、この発明の排気ガス浄化用触媒コンバータは、触媒保持体の外周部に、薄肉部および厚肉部を有する耐熱無機繊維マットを、その薄肉部が分割型シェルの合わせ目部分に合致する配置の下に巻き付けた後、耐熱無機繊維マットで覆われた触媒保持体を分割型シェルにて挟んで耐熱無機繊維マットを圧縮して組み付けることによって、有利に製造することができる。
【００１３】
ここで、耐熱無機繊維マットの薄肉部の厚さが、触媒保持体と分割型シェルとのクリアランスの１．１〜１．５倍であること、そして耐熱無機繊維マットの厚肉部の厚さが、触媒保持体と分割型シェルとのクリアランスの１．１〜２．１倍であること、が好ましい。
【００１４】
さらに、上記製造方法と同様に、触媒保持体の外周部に耐熱無機繊維マットを巻き付けたのち、触媒保持体と分割型シェルとのクリアランスが分割型シェルの合わせ目部分で大きく、それ以外の部分で小さく設定された、分割型シェルにて、耐熱無機繊維マットで覆われた触媒保持体を挟んで組み付けることによっても、この発明の排気ガス浄化用触媒コンバータを製造し得る。この場合は、均一な厚みの耐熱無機繊維マットを使用することができる。
【００１５】
【発明の実施の形態】
さて、この発明に従う排気ガス浄化用触媒コンバータは、図１に径方向に展開させた状態を示すように、白金などの触媒が保持された触媒保持体１、この触媒保持体１の外側を覆う結晶質セラミックファイバやシリカファイバ等の耐熱無機繊維による保持シール層２および保持シール層２の外側を覆う金属製の分割型シェル３，４から成る。とくに、保持シール層２について図２に示すように、分割型シェル３のフランジ３ａおよび３ｂと同シェル４のフランジ４ａおよび４ｂとが合わさる、合わせ目の近傍部分（以下、合わせ目部分という）２ａおよび２ｂにおける嵩密度に比して、それ以外の部分（以下、保持部分という）２ｃおよび２ｄにおける嵩密度を大きくしたことを特徴とするものである。
【００１６】
すなわち、保持シール層２における、保持部分２ｃおよび２ｄの嵩密度を合わせ目部分２ａおよび２ｂより大きくして、保持部分２ｃおよび２ｄにて触媒保持体１のシェル内での保持および振動に対する保護をはかることによって、合わせ目部分２ａおよび２ｂでは排気ガスをシールするに足る程度の嵩密度を付与したところに特徴がある。
【００１７】
ここに、合わせ目部分２ａおよび２ｂの嵩密度は、後述する排気ガスシール性および組立性の観点から、０．１６ｇ／ｃｍ3 〜０．３０ｇ／ｃｍ3 であることが好ましい。なぜなら、触媒保持体と分割型シェルとの間で排気ガスをシールするには、組立て後の保持シール層の嵩密度が０．１６ｇ／ｃｍ3 以上は必要である。すなわち、保持シール層は、触媒保持体の保持、さらに触媒保持体と分割型シェルとの間をシールして排気ガスが漏洩するのを防止するために用いられる。とくに、エンジン運転時と停止時において、セラミックス製の触媒保持体と金属製の分割型シェルとの熱膨張率が異なるために、両者間のクリアランスが変動し、また振動等の影響を受けるため、この過酷な条件下で触媒保持体と分割型シェルとの間で排気ガスの漏洩を防止するためには、組立て後の保持シール層の合わせ目部分２ａおよび２ｂの嵩密度が０．１６ｇ／ｃｍ3 以上であること、触媒保持体の外径寸法および分割型シェルの内径寸法がばらつくことを考慮すると０．２０ｇ／ｃｍ3 以上にすることがより好ましい。
【００１８】
一方、合わせ目部分２ａおよび２ｂの嵩密度が０．３０ｇ／ｃｍ3 をこえると、組立て時の耐熱無機繊維マットの圧縮率を極めて大きくしなければならず、組立て時に分割型シェルを合わせた際に、耐熱無機繊維マットが分割型シェルのフランジ部分からはみ出して噛み込まれる結果、分割型シェルの端部で耐熱無機繊維マットが削れたり、組立て後のフランジ部分の溶接が困難になる場合がある。
【００１９】
さらに、保持部分２ｃおよび２ｄの嵩密度は、０．２５〜０．５０ｇ／ｃｍ3 であることが好ましい。すなわち、保持部分２ｃおよび２ｄは、シール機能に加えて触媒保持体をシェル内に保持する役目をも担うために、０．２５ｇ／ｃｍ3 以上の嵩密度を有することが好ましい。一方、０．５０ｇ／ｃｍ3 をこえると、保持シール層を構成する耐熱無機繊維マットが徐々に圧壊して、組立て後の厚み方向の復元率が低下し、触媒保持体がシェル内でずれてしまう等の不利をまねき、さらに嵩密度が高くなると、触媒保持体自体が圧壊してしまう。
【００２０】
この保持シール層の合わせ目部分２ａおよび２ｂと保持部分２ｃおよび２ｄとの面積比は、触媒保持体および分割型シェルの形状などによって、適宜設定する必要があるが、耐久性の面からは、組立て可能な範囲で保持部分２ｃおよび２ｄの面積を多くすることが望ましい。具体的には、断面が円形の触媒保持体の場合、合わせ目部分２ａおよび２ｂが占める比率を、その円周の３０％前後とし、残りを保持部分２ｃおよび２ｄとすることが推奨される。
【００２１】
なお、保持シール層は、平均繊維径が２〜６μm 、アルミナ含有率が６０wt％以上の結晶質アルミナファイバーにて構成することが好ましい。同様に、触媒保持体には、例えばコージェライトによるセラミックスハニカム状のもの、あるいは金属箔をコルゲート加工したものを用いることができる。さらに、分割型シェルには、例えばＳＵＳ４０９に代表されるフェライト系ステンレス鋼製で円や長円断面形状の筒を２分割したものを用いることができる。
【００２２】
次に、上記した触媒コンバータの製造手順について、図面を参照して説明する。この発明に従う製造方法は、基本的に在来のクラムシェル方式と同様に、触媒保持体１に結晶質セラミックファイバ等の耐熱無機繊維マットを巻き付けてから、この触媒保持体１を分割型シェル３および４で挟み、該シェルのフランジ３ａと４ａ、３ｂと４ｂをそれぞれ溶接にて接合して、シェルと触媒保持体との間に耐熱無機繊維マットを組み付けて保持シール層を設ける、一連の工程からなる。
【００２３】
上記の製造工程において、触媒保持体１に巻き付ける耐熱無機繊維マットとして、図３に示すような耐熱無機繊維マット２０を用いる。すなわち、耐熱無機繊維マット２０は、薄肉部２０ａおよび２０ｂと、厚肉部２０ｃおよび２０ｄとからなり、具体的には、１枚のベースマット上にさらに所定寸法に裁断した２枚のパッチを離間して貼り合わせて、薄い部分と厚い部分を作成して用いる。なお、耐熱無機繊維マットとしては、厚肉部をパッチの貼り合わせで作成するのではなく、一体成形にて厚みを変化させたものを用いることも可能である。また、耐熱無機繊維マットは、例えば結晶質セラミックファイバのマットをポリエチレンフィルム等で真空パックしたもの、あるいはマットの表面を摩擦係数の小さいシート材で被覆したものを、使用することが好ましい。
【００２４】
そして、触媒保持体１に耐熱無機繊維マット２０を巻き付けたのち、図４に示すように、耐熱無機繊維マット２０の薄肉部２０ａおよび２０ｂに、分割型シェル３および４の合わせ目部分を合致させ、次いで図５に示すように、分割型シェルのフランジ３ａと４ａ、３ｂと４ｂをそれぞれ溶接にて接合すれば、耐熱無機繊維マット２０で覆われた触媒保持体１は分割型シェルに挟まれて組み付けが完了し、触媒保持体１と分割型シェル３および４との間に、保持シール層２が形成される。
【００２５】
かくして得られた保持シール層２は、耐熱無機繊維マット２０の薄肉部２０ａおよび２０ｂが合わせ目部分２ａおよび２ｂとなり、一方厚肉部２０ｃおよび２０ｄが保持部分２ｃおよび２ｄとなる。従って、薄肉部と厚肉部とが組み付け後は同じ厚みになるため、薄肉部での嵩密度は小さくなる一方、厚肉部での嵩密度は大きくなるのである。また、分割型シェル３および４の合わせ目に位置させる、耐熱無機繊維マットの薄肉部は、分割型シェル３および４を合わせる際の圧縮率が小さいため、シェルの合わせ目に向かってはみ出すことはなく、従って合わせ目に耐熱無機繊維マットが噛み込まれることはない。
【００２６】
ここで、組立て前の耐熱無機繊維マット２０の薄肉部２０ａおよび２０ｂの厚さが、触媒保持体１と分割型シェル３および４とのクリアランスの１．１〜１．５倍であることが、好ましい。なぜなら、薄肉部の厚さがクリアランスの１．１倍未満では、組立て時に触媒保持体の保持力が得られない結果、触媒保持体が前後にずれる可能性があり、一方クリアランスの１．５倍をこえる厚さでは、分割型シェルのフランジ部にマットが噛み込まれて組立て不能になる、おそれがある。
【００２７】
同様に、耐熱無機繊維マット２０の厚肉部２０ｃおよび２０ｄの厚さが、触媒保持体１と分割型シェル３および４とのクリアランスの１．１〜２．１倍であることが好ましい。なぜなら、厚肉部の厚さがクリアランスの１．１倍未満では、組立て時に触媒保持体の保持力が得られない結果、触媒保持体が前後にずれる可能性があり、一方クリアランスの２．１倍をこえる厚さでは、組立て時にマットあるいは触媒保持体自体が圧壊する、おそれがある。
【００２８】
また、組立て前の耐熱無機繊維マットの嵩密度は、０．１７〜０．２７ｇ／ｃｍ3 であることが好ましい。なぜなら、嵩密度が０．１７ｇ／ｃｍ3 未満では、組立て後に所望の嵩密度にすることが難しく、排気ガスのリークが心配され、一方嵩密度が０．２７ｇ／ｃｍ3 をこえると、分割型シェル内へ組付けるために、例えば有機バインダーを多量に添加する等、組立て作業性が著しく阻害される。
【００２９】
さらに、耐熱無機繊維マットにおける薄肉部および厚肉部の面積比は、触媒保持体および分割型シェルの形状などによって、適宜設定する必要があるが、耐久性の面からは、組立て可能な範囲で厚肉部の面積を多くすることが望ましい。具体的には、断面が円形の触媒保持体の場合、薄肉部が占める比率を、その円周の３０％前後とし、残りを厚肉部とすることが推奨される。
【００３０】
なお、耐熱無機繊維マットには、図３に示したように、予め薄肉部および厚肉部を設けたものを使用したが、触媒保持体に１枚のシート材を巻き付けたのち、厚肉部に相当する部分にシート材を部分的に追加してから、組立てを行うことも可能である。とくに、耐熱無機繊維マットの薄肉部と厚肉部との厚みに極端な差を設けて、保持シール層における嵩密度の差を大きくしたい場合には、追加する耐熱無機繊維マットを斜めにカットしたり、追加する耐熱無機繊維マットを複層とすればよい。
【００３１】
また、耐熱無機繊維マットの厚みや嵩密度を一定にしておき、分割型シェルの形状で対応することも可能である。すなわち、図６に示すように、予め分割型シェル３および４と触媒保持体１とのクリアランスをシェルの合わせ目部分近傍では大きく、その他の部分を小さくしておけばよい。その他にも、分割型シェルの合わせ目部分近傍以外の部分のシェル内側にビードを設けてもよい。
【００３２】
なお、分割型シェル内への耐熱無機繊維マットの組付けが容易に行われるためには、真空パックフィルム等の摩擦係数の低い材料で耐熱無機繊維マットを覆って、耐熱無機繊維マットの表面に潤滑性を付与することが好ましい。
ちなみに、前記排ガス浄化用コンバーターは、自動車製造工場において、エンジンの排気ガスパイプに接続され、その試運転の際には、高温度の排ガスによって、接着剤、真空パックフィルム等が焼却されるのが通例である。但し、加熱分解時発生するガスが有害でない成分のものを選択する必要はある。
【００３３】
【実施例】
実施例１
図１に示した構造に従って、外径１００ｍｍのコーディエライトの触媒保持体１と、この触媒保持体１の外側を覆う内径１０８ｍｍのＳＵＳ４０９製の分割型シェル３および４との間に、保持シール層２を設けた排気ガス浄化用触媒コンバータを、図３〜５に示したところに従って製造した。
【００３４】
すなわち、耐熱無機繊維マット２０には、結晶質アルミナファイバーのマット（デンカアルセン電気化学工業（株）製）を使用し、図３に示したように、厚み１２ｍｍ、嵩密度０．０８ｇ／ｃｍ3 のベースマットに、厚み６ｍｍ、嵩密度０．０８ｇ／ｃｍ3 の２枚のパッチを貼り当てて、薄肉部２０ａおよび２０ｂと、厚肉部２０ｃおよび２０ｄとを形成し、その後真空パックにより保護した。真空パック後の厚みおよび嵩密度は、薄肉部が４．４ｍｍおよび０．２２ｇ／ｃｍ3 、そして厚肉部が６．５ｍｍおよび０．２２ｇ／ｃｍ3 であった。
【００３５】
次いで、耐熱無機繊維マット２０を触媒保持体１に巻付けて粘着テープ等で仮止めした後、図４に示したように、分割型シェル３および４を配置してから分割型シェル３および４で触媒保持体１を挟み込んだ後、シェルのフランジ３ａと４ａ、３ｂと４ｂをそれぞれ溶接して、図５に示す触媒コンバータを得た。
【００３６】
ここで、触媒保持体１の外周に巻付けた耐熱無機繊維マット２０を分割型シェル３および４で挟み込む際に、該シェルのフランジ３ａと４ａあるいは３ｂと４ｂの間に、耐熱無機繊維マット２０を噛み込むことなく組立てが完了した。
【００３７】
かくして得られた触媒コンバータの保持シール層２における、合わせ目部分の嵩密度は０．２４ｇ／ｃｍ3 および保持部分の嵩密度は０．３６ｇ／ｃｍ3 であった。なお、触媒保持体１と分割型シェル３および４とのクリアランスは、４ｍｍである。
【００３８】
次に、組立てた触媒コンバータを、３リットルのガソリンエンジンに接続し、エンジン回転数をアイドリングから５５００ｒｐｍまで１０分間で上昇させ、その後５分間でアイドリングに戻す試験を、連続で５００時間行った後、分割型シェルを開封して内部を観察したが、触媒保持体および保持シール層に損傷は見られず、また排気ガスが漏れた痕跡も見られなかった。
【００３９】
実施例２
実施例１と同様の触媒保持体１を用いて、分割型シェルと触媒保持体とのクリアランスを、図６に示すように、分割型シェルの合わせ目で６ｍｍとし、この合わせ目からシェルの頂点へクリアランスを漸減して頂点のクリアランスを４ｍｍとした。耐熱無機繊維マット２０には、厚み１８ｍｍおよび嵩密度０．０８ｇ／ｃｍ3 の結晶質アルミナファイバーのマットを真空パックにより厚み６．５ｍｍおよび嵩密度０．２２ｇ／ｃｍ3 としたものを用いた。以上の条件に従って、触媒保持体１の外周に耐熱無機繊維マット２０を巻付けたのち、分割型シェル３および４で挟み込み、図６に示す触媒コンバータを得た。
【００４０】
かくして得られた触媒コンバータの保持シール層２における、合わせ目部分の嵩密度は０．２４ｇ／ｃｍ3 および保持部分の嵩密度は０．３６ｇ／ｃｍ3 であった。
【００４１】
ここで、触媒保持体１の外周に巻付けた耐熱無機繊維マット２０を分割型シェル３および４で挟み込む際に、該シェルのフランジ３ａと４ａあるいは３ｂと４ｂの間に、耐熱無機繊維マット２０を噛み込むことなく組立てが完了した。また、組立て後の触媒コンバータを、実施例１と同様に、エンジン評価を行ったところ、問題は見られなかった。
【００４２】
比較例
実施例１と同様の製造工程において、触媒保持体１に巻き付ける耐熱無機繊維マットとして、図７に示す均一な厚さのものを用いた。すなわち、厚み１８ｍｍおよび嵩密度０．０８ｇ／ｃｍ3 の耐熱無機繊維マット３０を真空パックして用いた。真空パック後の厚みおよび嵩密度は、それぞれ６．５ｍｍおよび０．２２ｇ／ｃｍ3 であった。
【００４３】
そして、この耐熱無機繊維マット３０を触媒保持体１に巻付け、粘着テープ等で仮止めした後分割型シェル３および４で挟み込んでところ、図８に示すように、フランジ３ａと４ａ、さらに３ｂと４ｂ間に耐熱無機繊維マット３０が噛み込んで、フランジの溶接が行えず、組立ては実現しなかった。
【００４４】
【発明の効果】
この発明によれば、組立て時に耐熱無機繊維マットが分割型シェルに噛み込むことなしに、所望の嵩密度を有する保持シール層を設けることができるため、触媒保持体と分割型シェルとの間のシール機能に優れる排気ガス浄化用触媒コンバータを提供し得る。
【図面の簡単な説明】
【図１】排気ガス浄化用触媒コンバーターの構造を示す斜視図である。
【図２】保持シール層の構造を示す図である。
【図３】耐熱無機繊維マットを示す図である。
【図４】排気ガス浄化用触媒コンバーターの製造手順を説明する図である。
【図５】排気ガス浄化用コンバーターの断面図である。
【図６】別の手法によって製造した排気ガス浄化用コンバーターの断面図である。
【図７】従来の製造方法で用いていた耐熱無機繊維マットを示す図である。
【図８】従来の製造手順を説明する図である。
【符号の説明】
１ 触媒保持体
２ 保持シール層
２ａ，２ｂ 合わせ目部分
２ｃ，２ｄ 保持部分
３，４ 分割型シェル
３ａ，３ｂ，４ａ，４ｂ フランジ
２０ 耐熱無機繊維マット
２０ａ，２０ｂ 薄肉部
２０ｃ，２０ｄ 厚肉部[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to an exhaust gas purifying converter that is provided in the exhaust pipe or in an exhaust manifold to purify exhaust gas in an exhaust system of a vehicle, particularly a crystalline alumina fiber between a catalyst holding body and a split shell. The present invention relates to a catalytic converter for purifying exhaust gas with a holding seal layer made of a heat-resistant inorganic fiber mat and a method for producing the same.
[0002]
[Prior art]
Conventionally, an exhaust gas purification catalytic converter has a structure in which a holding seal layer is provided between a catalyst holding body holding a catalyst such as platinum and a cylindrical metal shell covering the outside of the catalyst holding body. It has been known. Note that a cordierite carrier having a honeycomb cross section is generally used for the catalyst holder.
[0003]
In addition, the holding seal layer has been mainly composed of a mixture of unexpanded vermiculite and ceramic fibers. However, as the performance of the engine in recent years has increased, the temperature of the exhaust gas has increased and the heat resistance to the holding seal layer has been increased. However, since the heat resistance temperature of vermiculite is not so high, application of a holding seal layer made of heat resistant inorganic fibers such as crystalline alumina fibers has been attempted.
[0004]
In this type of exhaust gas purifying catalytic converter, a heat-resistant inorganic fiber mat serving as a holding seal layer is wound around a catalyst holding body, and then the catalyst holding body is sandwiched between two divided shells and assembled. It is common to produce the clamshell method.
[0005]
However, when a heat-resistant inorganic fiber mat made of heat-resistant inorganic fibers is wrapped around the catalyst holder and sandwiched between the split-type shells and assembled, the heat-resistant inorganic fiber mat is caught in the joints of the split-type shells, Since the sliding with the fiber mat is poor, the heat-resistant inorganic fiber mat is damaged.
[0006]
In order to solve these problems, a so-called vacuum packing method for heat-resistant inorganic fiber mats with a sealed film has been proposed in, for example, Japanese Patent Application Laid-Open No. 57-146554. Here, the heat-resistant inorganic fiber mat is reduced in thickness by a vacuum pack, but since this thickness reduction is performed using a differential pressure inside and outside the vacuum pack, a compressive force exceeding atmospheric pressure cannot be applied. Therefore, the bulk density of the heat-resistant inorganic fiber mat that has been vacuum-packed and incorporated in the split-type shell is not so high as compared with the heat-resistant inorganic fiber mat before the vacuum packing.
[0007]
[Problems to be solved by the invention]
By the way, the holding seal layer of the exhaust gas purifying catalytic converter holds the catalyst holding body in the split shell, and the catalyst holding body is damaged by hitting the outer split shell due to vibration or the like while the automobile is running. This is used to prevent exhaust gas from leaking between the split shell and the catalyst holder.
[0008]
That is, the holding seal layer obtained by incorporating the heat-resistant inorganic fiber mat into the split-type shell requires, for example, a bulk density of 0.2 g / cm 3 or more, preferably 0.3 g / cm 3 or more. In the method using the vacuum pack, since the compressive force is small, it is difficult to obtain the bulk density so far. Although it is conceivable to increase the bulk density of the heat-resistant inorganic fiber mat before the vacuum packing, if the bulk density is increased, a predetermined thickness reduction is not achieved by the vacuum pack, and the heat-resistant inorganic fiber mat is separated from the split shell. Since it becomes easy to bite into the joint, it cannot be adopted.
[0009]
Accordingly, the present invention intends to provide an exhaust gas purifying catalytic converter having a bulk density sufficient to function as a holding seal layer without causing the above-mentioned disadvantages.
[0010]
[Means for Solving the Problems]
The present invention relates to an exhaust gas purifying catalytic converter in which a holding seal layer mainly composed of heat-resistant inorganic fibers is provided between a catalyst holding body and a metal divided shell covering the outside of the catalyst holding body. The holding seal layer is an exhaust gas purifying catalytic converter characterized in that the bulk density of the other portion is made larger than the bulk density in the vicinity of the joint of the split shell.
[0011]
Here, the bulk density in the vicinity of the joint of the split shell of the holding seal layer is 0.16 to 0.30 g / cm 3 , and the bulk density in the portion other than the vicinity of the joint of the split shell of the holding seal layer it There is 0.25~0.50g / cm 3, and crystalline alumina fibers constituting the holding sealing layer, the average fiber diameter of 2~6μm and alumina content is not less than 60 wt%, the in implementing It is advantageous.
[0012]
Further, in the exhaust gas purifying catalytic converter of the present invention, a heat-resistant inorganic fiber mat having a thin portion and a thick portion is disposed on the outer peripheral portion of the catalyst holding body, and the thin portion matches the joint portion of the split shell. After being wound around, the catalyst holder covered with the heat-resistant inorganic fiber mat is sandwiched between the split-type shells, and the heat-resistant inorganic fiber mat is compressed and assembled.
[0013]
Here, the thickness of the thin part of the heat resistant inorganic fiber mat is 1.1 to 1.5 times the clearance between the catalyst holder and the split shell, and the thickness of the thick part of the heat resistant inorganic fiber mat. Is preferably 1.1 to 2.1 times the clearance between the catalyst support and the split shell.
[0014]
Furthermore, after the heat-resistant inorganic fiber mat is wound around the outer periphery of the catalyst holder, the clearance between the catalyst holder and the split-type shell is large at the joint portion of the split-type shell, as in the above manufacturing method. The exhaust gas purifying catalytic converter of the present invention can also be manufactured by assembling a catalyst holding body covered with a heat-resistant inorganic fiber mat with a split shell set to a small size. In this case, a heat-resistant inorganic fiber mat having a uniform thickness can be used.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Now, the exhaust gas purifying catalytic converter according to the present invention covers a catalyst holding body 1 holding a catalyst such as platinum and the outside of the catalyst holding body 1 as shown in FIG. The holding seal layer 2 is made of a heat-resistant inorganic fiber such as a crystalline ceramic fiber or a silica fiber, and the metal divided shells 3 and 4 that cover the outside of the holding seal layer 2 are formed. In particular, as shown in FIG. 2 for the holding seal layer 2, a portion near the joint (hereinafter referred to as a joint portion) 2 a where the flanges 3 a and 3 b of the split shell 3 and the flanges 4 a and 4 b of the shell 4 are combined. In comparison with the bulk density in 2b and 2b, the bulk density in the other parts (hereinafter referred to as holding parts) 2c and 2d is increased.
[0016]
That is, the bulk density of the holding portions 2c and 2d in the holding seal layer 2 is made larger than that of the joint portions 2a and 2b so that the holding portions 2c and 2d can be held in the shell of the catalyst holder 1 and protected against vibration. By measuring, the joint portions 2a and 2b are characterized in that a bulk density sufficient to seal the exhaust gas is given.
[0017]
Here, the bulk density of the joint portion 2a and 2b, from the viewpoint of the exhaust gas sealing property and assembling property to be described later, is preferably 0.16g / cm 3 ~0.30g / cm 3 . This is because, in order to seal the exhaust gas between the catalyst holder and the split shell, the bulk density of the holding seal layer after assembly is required to be 0.16 g / cm 3 or more. That is, the holding seal layer is used for holding the catalyst holding body, and further sealing the space between the catalyst holding body and the divided shell to prevent the exhaust gas from leaking. In particular, because the coefficient of thermal expansion of the ceramic catalyst holder and the metal split-type shell differs during engine operation and when the engine is stopped, the clearance between the two fluctuates and is affected by vibrations, etc. In order to prevent the exhaust gas from leaking between the catalyst holder and the split shell under this severe condition, the bulk density of the joint portions 2a and 2b of the holding seal layer after assembly is 0.16 g / cm. 3 or more that it is, it is more preferable that the 0.20 g / cm 3 or more considering that the inner diameter of the outer diameter and divided shell of the catalyst retainer varies.
[0018]
On the other hand, if the bulk density of the joint portions 2a and 2b exceeds 0.30 g / cm 3 , the compressibility of the heat-resistant inorganic fiber mat at the time of assembly must be extremely large. In addition, as a result of the heat-resistant inorganic fiber mat protruding from the flange portion of the split-type shell and being bitten, the heat-resistant inorganic fiber mat may be scraped off at the end of the split-type shell or it may be difficult to weld the flange portion after assembly. .
[0019]
Furthermore, the bulk density of the holding portions 2c and 2d is preferably 0.25 to 0.50 g / cm 3 . That is, the holding portions 2c and 2d preferably have a bulk density of 0.25 g / cm 3 or more in order to play a role of holding the catalyst holding body in the shell in addition to the sealing function. On the other hand, if it exceeds 0.50 g / cm 3 , the heat-resistant inorganic fiber mat constituting the holding seal layer is gradually crushed, the restoration rate in the thickness direction after assembly is lowered, and the catalyst holder is displaced in the shell. If the bulk density is further increased, the catalyst holder itself is crushed.
[0020]
The area ratio between the joint portions 2a and 2b and the holding portions 2c and 2d of the holding seal layer needs to be set as appropriate depending on the shape of the catalyst holding body and the split-type shell, but from the viewpoint of durability, It is desirable to increase the area of the holding portions 2c and 2d within a range that can be assembled. Specifically, in the case of a catalyst holding body having a circular cross section, it is recommended that the ratio occupied by the joint portions 2a and 2b be around 30% of the circumference and the remaining portions be holding portions 2c and 2d.
[0021]
The holding seal layer is preferably composed of crystalline alumina fibers having an average fiber diameter of 2 to 6 μm and an alumina content of 60 wt% or more. Similarly, as the catalyst holding body, for example, a ceramic honeycomb shape made of cordierite or a corrugated metal foil can be used. Furthermore, as the split-type shell, for example, a ferritic stainless steel typified by SUS409, which is a cylinder having a circular or oval cross-sectional shape divided into two, can be used.
[0022]
Next, the manufacturing procedure of the catalytic converter described above will be described with reference to the drawings. In the manufacturing method according to the present invention, basically, a heat-resistant inorganic fiber mat such as a crystalline ceramic fiber is wound around the catalyst holding body 1 in the same manner as in the conventional clamshell method, and then the catalyst holding body 1 is divided into the split shell 3. A series of steps in which the flanges 3a and 4a, 3b and 4b of the shell are joined by welding and a heat-resistant inorganic fiber mat is assembled between the shell and the catalyst holding body to provide a holding seal layer. Consists of.
[0023]
In the manufacturing process described above, a heat resistant inorganic fiber mat 20 as shown in FIG. 3 is used as the heat resistant inorganic fiber mat wound around the catalyst holder 1. That is, the heat-resistant inorganic fiber mat 20 includes thin portions 20a and 20b and thick portions 20c and 20d. Specifically, two patches cut into a predetermined size on one base mat are separated from each other. Then, a thin part and a thick part are created and used. In addition, as a heat-resistant inorganic fiber mat, it is also possible to use a thick-walled part whose thickness is changed by integral molding, instead of creating a thick part by bonding patches. In addition, it is preferable to use a heat-resistant inorganic fiber mat, for example, a crystalline ceramic fiber mat vacuum-packed with a polyethylene film or the like, or a mat surface coated with a sheet material having a small friction coefficient.
[0024]
Then, after the heat-resistant inorganic fiber mat 20 is wound around the catalyst holder 1, as shown in FIG. 4, the joint portions of the split-type shells 3 and 4 are matched with the thin portions 20a and 20b of the heat-resistant inorganic fiber mat 20. Then, as shown in FIG. 5, if the flanges 3a and 4a, 3b and 4b of the split-type shell are joined by welding, the catalyst holder 1 covered with the heat-resistant inorganic fiber mat 20 is sandwiched between the split-type shells. Thus, the assembly is completed, and the holding seal layer 2 is formed between the catalyst holding body 1 and the divided shells 3 and 4.
[0025]
In the holding seal layer 2 thus obtained, the thin portions 20a and 20b of the heat-resistant inorganic fiber mat 20 become seam portions 2a and 2b, while the thick portions 20c and 20d become holding portions 2c and 2d. Therefore, since the thin wall portion and the thick wall portion have the same thickness after assembly, the bulk density in the thin wall portion is reduced, while the bulk density in the thick wall portion is increased. In addition, the thin portion of the heat-resistant inorganic fiber mat located at the joint between the split-type shells 3 and 4 has a small compression rate when the split-type shells 3 and 4 are put together, and therefore does not protrude toward the joint between the shells. Therefore, the heat-resistant inorganic fiber mat is not caught in the joint.
[0026]
Here, the thickness of the thin portions 20a and 20b of the heat-resistant inorganic fiber mat 20 before assembly is 1.1 to 1.5 times the clearance between the catalyst holding body 1 and the split-type shells 3 and 4. preferable. This is because if the thickness of the thin wall portion is less than 1.1 times the clearance, the catalyst holding body may not have a holding force during assembly, and as a result, the catalyst holding body may shift back and forth, while the clearance is 1.5 times the clearance. If the thickness exceeds 50 mm, the mat may be caught in the flange portion of the split-type shell, making it impossible to assemble.
[0027]
Similarly, the thickness of the thick portions 20c and 20d of the heat-resistant inorganic fiber mat 20 is preferably 1.1 to 2.1 times the clearance between the catalyst holder 1 and the split-type shells 3 and 4. This is because if the thickness of the thick portion is less than 1.1 times the clearance, the holding force of the catalyst holding body cannot be obtained at the time of assembling, and as a result, the catalyst holding body may shift back and forth, while the clearance of 2.1. If the thickness exceeds twice, the mat or the catalyst holder itself may be crushed during assembly.
[0028]
The bulk density of the heat-resistant inorganic fiber mat before assembly is preferably 0.17 to 0.27 g / cm 3 . This is because if the bulk density is less than 0.17 g / cm 3 , it is difficult to achieve a desired bulk density after assembly, and there is a concern about exhaust gas leakage, while if the bulk density exceeds 0.27 g / cm 3 , For assembling into the shell, for example, a large amount of an organic binder is added, so that the assembly workability is significantly hindered.
[0029]
Furthermore, the area ratio of the thin-walled portion and the thick-walled portion in the heat-resistant inorganic fiber mat needs to be appropriately set depending on the shape of the catalyst holder and the split-type shell, but from the viewpoint of durability, it can be assembled within the range that can be assembled. It is desirable to increase the area of the thick part. Specifically, in the case of a catalyst holding body having a circular cross section, it is recommended that the ratio occupied by the thin portion is about 30% of the circumference and the remaining portion is the thick portion.
[0030]
In addition, as shown in FIG. 3, the heat-resistant inorganic fiber mat used in advance was provided with a thin portion and a thick portion. However, after the sheet material was wound around the catalyst holder, the thick portion It is also possible to assemble after partially adding a sheet material to the portion corresponding to. In particular, if you want to increase the difference in bulk density in the holding seal layer by providing an extreme difference in the thickness between the thin and thick parts of the heat-resistant inorganic fiber mat, cut the heat-resistant inorganic fiber mat to be added diagonally. Or the heat-resistant inorganic fiber mat to be added may be a multilayer.
[0031]
It is also possible to keep the thickness and bulk density of the heat-resistant inorganic fiber mat constant and cope with the shape of the split shell. That is, as shown in FIG. 6, the clearance between the split-type shells 3 and 4 and the catalyst holding body 1 may be increased in the vicinity of the joint portion of the shell and the other portions may be reduced in advance. In addition, a bead may be provided inside the shell other than the vicinity of the joint portion of the split shell.
[0032]
For easy assembly of the heat resistant inorganic fiber mat in the split shell, the heat resistant inorganic fiber mat is covered with a material having a low coefficient of friction such as a vacuum pack film, and the surface of the heat resistant inorganic fiber mat is covered. It is preferable to impart lubricity.
Incidentally, the exhaust gas purification converter is connected to the exhaust gas pipe of an engine in an automobile manufacturing factory, and the adhesive, the vacuum pack film, etc. are usually incinerated by high temperature exhaust gas during the trial operation. is there. However, it is necessary to select a component in which the gas generated during the thermal decomposition is not harmful.
[0033]
【Example】
Example 1
In accordance with the structure shown in FIG. 1, a holding seal is provided between a cordierite catalyst holder 1 with an outer diameter of 100 mm and split type shells 3 and 4 made of SUS409 with an inner diameter of 108 mm covering the outside of the catalyst holder 1. An exhaust gas purifying catalytic converter provided with the layer 2 was produced according to the manner shown in FIGS.
[0034]
That is, as the heat resistant inorganic fiber mat 20, a crystalline alumina fiber mat (manufactured by Denka Alsen Denki Kagaku Kogyo Co., Ltd.) is used. As shown in FIG. 3, the thickness is 12 mm and the bulk density is 0.08 g / cm 3. Two patches having a thickness of 6 mm and a bulk density of 0.08 g / cm 3 were applied to the base mat to form the thin portions 20a and 20b and the thick portions 20c and 20d, which were then protected by a vacuum pack. . Thickness and bulk density after the vacuum pack, the thin portion is 4.4mm and 0.22 g / cm 3, and the thick portion was 6.5mm and 0.22 g / cm 3.
[0035]
Next, the heat-resistant inorganic fiber mat 20 is wound around the catalyst holding body 1 and temporarily fixed with an adhesive tape or the like, and then the split-type shells 3 and 4 are arranged as shown in FIG. Then, after sandwiching the catalyst holder 1, the flanges 3a and 4a, 3b and 4b of the shell were welded to obtain the catalytic converter shown in FIG.
[0036]
Here, when the heat-resistant inorganic fiber mat 20 wound around the outer periphery of the catalyst holder 1 is sandwiched between the split-type shells 3 and 4, the heat-resistant inorganic fiber mat 20 is sandwiched between the flanges 3a and 4a or 3b and 4b of the shell. The assembly was completed without biting.
[0037]
In the thus obtained holding seal layer 2 of the catalytic converter, the bulk density of the joint portion was 0.24 g / cm 3 and the bulk density of the holding portion was 0.36 g / cm 3 . The clearance between the catalyst holder 1 and the split shells 3 and 4 is 4 mm.
[0038]
Next, after the assembled catalytic converter was connected to a 3 liter gasoline engine, the engine speed was increased from idling to 5500 rpm in 10 minutes and then returned to idling in 5 minutes, after 500 hours of continuous testing. The split shell was opened and the inside was observed, but no damage was observed on the catalyst holder and the holding seal layer, and no trace of exhaust gas leakage was found.
[0039]
Example 2
Using the same catalyst holder 1 as in Example 1, the clearance between the split shell and the catalyst holder is 6 mm at the joint of the split shell, as shown in FIG. The clearance at the top was gradually reduced to 4 mm. The heat inorganic fiber mat 20, was used as the thickness 6.5mm and a bulk density of 0.22 g / cm 3 crystalline alumina fiber mat having a thickness of 18mm and a bulk density of 0.08 g / cm 3 by vacuum packing. In accordance with the above conditions, the heat-resistant inorganic fiber mat 20 was wound around the outer periphery of the catalyst holder 1, and then sandwiched between the split-type shells 3 and 4 to obtain the catalytic converter shown in FIG.
[0040]
In the thus obtained holding seal layer 2 of the catalytic converter, the bulk density of the joint portion was 0.24 g / cm 3 and the bulk density of the holding portion was 0.36 g / cm 3 .
[0041]
Here, when the heat-resistant inorganic fiber mat 20 wound around the outer periphery of the catalyst holder 1 is sandwiched between the split-type shells 3 and 4, the heat-resistant inorganic fiber mat 20 is sandwiched between the flanges 3a and 4a or 3b and 4b of the shell. The assembly was completed without biting. Further, when the assembled catalytic converter was evaluated for the engine in the same manner as in Example 1, no problem was found.
[0042]
Comparative Example In the same manufacturing process as in Example 1, a heat-resistant inorganic fiber mat wound around the catalyst support 1 was used with a uniform thickness shown in FIG. That is, a heat-resistant inorganic fiber mat 30 having a thickness of 18 mm and a bulk density of 0.08 g / cm 3 was vacuum packed and used. The thickness and bulk density after vacuum packing were 6.5 mm and 0.22 g / cm 3 , respectively.
[0043]
Then, when the heat-resistant inorganic fiber mat 30 is wound around the catalyst holder 1 and temporarily fixed with an adhesive tape or the like and sandwiched between the split-type shells 3 and 4, as shown in FIG. 8, the flanges 3a and 4a, and further 3b 4b, the heat-resistant inorganic fiber mat 30 was caught, and the flange could not be welded, and assembly was not realized.
[0044]
【The invention's effect】
According to this invention, since the heat-resistant inorganic fiber mat can be provided with a desired bulk density without being bitten into the split shell at the time of assembly, it can be provided between the catalyst holder and the split shell. An exhaust gas purifying catalytic converter having an excellent sealing function can be provided.
[Brief description of the drawings]
FIG. 1 is a perspective view showing the structure of an exhaust gas purifying catalytic converter.
FIG. 2 is a view showing a structure of a holding seal layer.
FIG. 3 is a view showing a heat-resistant inorganic fiber mat.
FIG. 4 is a diagram for explaining a manufacturing procedure of an exhaust gas purifying catalytic converter.
FIG. 5 is a cross-sectional view of an exhaust gas purifying converter.
FIG. 6 is a cross-sectional view of an exhaust gas purification converter manufactured by another method.
FIG. 7 is a view showing a heat-resistant inorganic fiber mat used in a conventional manufacturing method.
FIG. 8 is a diagram for explaining a conventional manufacturing procedure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Catalyst holding body 2 Holding seal layer 2a, 2b Joint part 2c, 2d Holding part 3, 4 Split type | mold shell 3a, 3b, 4a, 4b Flange 20 Heat resistant inorganic fiber mat 20a, 20b Thin part 20c, 20d Thick part

Claims (12)

触媒保持体と、この触媒保持体の外側を覆う金属製の分割型シェルとの間に、主に耐熱無機繊維から構成された保持シール層を設けた排気ガス浄化用触媒コンバータにおいて、
上記保持シール層は、分割型シェルの合わせ目近傍部分における嵩密度に比して、それ以外の部分の嵩密度を大きくしたことを特徴とする排気ガス浄化用触媒コンバータ。In an exhaust gas purifying catalytic converter provided with a holding seal layer mainly composed of heat-resistant inorganic fibers, between a catalyst holder and a metal divided shell covering the outside of the catalyst holder,
The holding seal layer is an exhaust gas purifying catalytic converter characterized in that the bulk density of the other part is larger than the bulk density in the vicinity of the joint of the split shell. 保持シール層の分割型シェルの合わせ目近傍部分における嵩密度が０．１６〜０．３０ｇ／ｃｍ3 である請求項１記載の排気ガス浄化用触媒コンバータ。2. The exhaust gas purifying catalytic converter according to claim 1, wherein the bulk density of the holding seal layer in the vicinity of the joint of the split shell is 0.16 to 0.30 g / cm < 3 >. 保持シール層の分割型シェルの合わせ目近傍以外の部分における嵩密度が０．２５〜０．５０ｇ／ｃｍ3 である請求項１または２記載の排気ガス浄化用触媒コンバータ。 3. The exhaust gas purifying catalytic converter according to claim 1, wherein a bulk density in a portion of the holding seal layer other than the vicinity of the joint of the split-type shell is 0.25 to 0.50 g / cm 3 . 保持シール層が、平均繊維径が２〜６μm およびアルミナ含有率が６０wt％以上の結晶質アルミナファイバからなる請求項１、２または３記載の排気ガス浄化用触媒コンバータ。The exhaust gas purifying catalytic converter according to claim 1, 2 or 3, wherein the holding seal layer is made of crystalline alumina fiber having an average fiber diameter of 2 to 6 µm and an alumina content of 60 wt% or more. 触媒保持体と、この触媒保持体の外側を覆う金属製の分割型シェルとの間に、主に耐熱無機繊維から構成された保持シール層を設けた排気ガス浄化用触媒コンバータを製造するに当たり、
上記触媒保持体の外周部に、薄肉部および厚肉部を有する耐熱無機繊維マットを、その薄肉部が分割型シェルの合わせ目部分に合致する配置の下に巻き付けた後、耐熱無機繊維マットで覆われた触媒保持体を分割型シェルにて挟んで耐熱無機繊維マットを圧縮して組み付けることを特徴とする排気ガス浄化用触媒コンバータの製造方法。In producing an exhaust gas purifying catalytic converter provided with a holding seal layer mainly composed of heat-resistant inorganic fibers between a catalyst holding body and a metal divided shell covering the outside of the catalyst holding body,
A heat-resistant inorganic fiber mat having a thin-walled portion and a thick-walled portion is wound around the outer periphery of the catalyst holder under an arrangement in which the thin-walled portion matches the joint portion of the split-type shell, and then the heat-resistant inorganic fiber mat is used. A method for producing a catalytic converter for purifying exhaust gas, wherein the heat-resistant inorganic fiber mat is compressed and assembled by sandwiching a covered catalyst holder between split shells. 耐熱無機繊維マットの薄肉部の厚さが、触媒保持体と分割型シェルとのクリアランスの１．１〜１．５倍である請求項５記載の排気ガス浄化用触媒コンバータの製造方法。6. The method for producing an exhaust gas purifying catalytic converter according to claim 5, wherein the thickness of the thin portion of the heat-resistant inorganic fiber mat is 1.1 to 1.5 times the clearance between the catalyst holder and the split shell. 耐熱無機繊維マットの厚肉部の厚さが、触媒保持体と分割型シェルとのクリアランスの１．１〜２．１倍である請求項５または６記載の排気ガス浄化用触媒コンバータの製造方法。The method for producing a catalytic converter for exhaust gas purification according to claim 5 or 6, wherein the thickness of the thick portion of the heat-resistant inorganic fiber mat is 1.1 to 2.1 times the clearance between the catalyst holder and the split shell. . 触媒保持体と、この触媒保持体の外側を覆う金属製の分割型シェルとの間に、主に耐熱無機繊維から構成された保持シール層を設けた排気ガス浄化用触媒コンバータを製造するに当たり、
上記触媒保持体の外周部に耐熱無機繊維マットを巻き付けたのち、触媒保持体と分割型シェルとのクリアランスが分割型シェルの合わせ目部分で大きく、それ以外の部分で小さく設定された、分割型シェルにて、耐熱無機繊維マットで覆われた触媒保持体を挟んで組み付けることを特徴とする排気ガス浄化用触媒コンバータの製造方法。In producing an exhaust gas purifying catalytic converter provided with a holding seal layer mainly composed of heat-resistant inorganic fibers between a catalyst holding body and a metal divided shell covering the outside of the catalyst holding body,
After the heat-resistant inorganic fiber mat is wound around the outer periphery of the catalyst holder, the clearance between the catalyst holder and the split-type shell is set large at the joint portion of the split-type shell, and is set small at the other portions. A method for producing a catalytic converter for purifying exhaust gas, comprising assembling a catalyst holding body covered with a heat-resistant inorganic fiber mat with a shell. 触媒保持体と、この触媒保持体の外側を覆う金属製の分割型シェルとの間に、保持シール層を設けた排気ガス浄化用触媒コンバータにおける、該保持シール層に供する耐熱無機繊維マットであって、２つの厚肉部を離間して設けて成ることを特徴とする排気ガス浄化用触媒コンバータに供する耐熱無機繊維マット。A heat-resistant inorganic fiber mat to be used for a holding seal layer in an exhaust gas purification catalytic converter in which a holding seal layer is provided between a catalyst holder and a metal divided shell covering the outside of the catalyst holder. A heat-resistant inorganic fiber mat for use in an exhaust gas purifying catalytic converter, characterized in that two thick parts are provided apart from each other. １枚のベースマット上に、２枚のパッチを離間して貼り合わせて厚肉部としたことを特徴とする請求項９記載の排気ガス浄化用触媒コンバータに供する耐熱無機繊維マット。10. The heat resistant inorganic fiber mat for use in an exhaust gas purifying catalytic converter according to claim 9, wherein two patches are separated and bonded to form a thick portion on one base mat. 請求項９または１０において、フィルムによる真空パックを施して成ることを特徴とする排気ガス浄化用触媒コンバータに供する耐熱無機繊維マット。11. The heat-resistant inorganic fiber mat for use in an exhaust gas purifying catalytic converter according to claim 9 or 10, wherein the heat-resistant inorganic fiber mat is used for an exhaust gas purifying catalytic converter. 請求項９または１０において、表面を低摩擦係数シート材で被覆して成ることを特徴とする排気ガス浄化用触媒コンバータに供する耐熱無機繊維マット。11. The heat-resistant inorganic fiber mat for use in an exhaust gas purifying catalytic converter according to claim 9 or 10, wherein the surface is coated with a low friction coefficient sheet material.
JP00428797A 1997-01-14 1997-01-14 EXHAUST GAS PURIFYING CATALYST CONVERTER, PROCESS FOR PRODUCING THE SAME, AND HEAT-RESISTANT INORGANIC FIBER MAT FOR USE IN EXHAUST GAS PURIFYING CATALYST CONVERTER Expired - Lifetime JP3833761B2 (en)

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JP5288115B2 (en) * 2008-12-10 2013-09-11 ニチアス株式会社 Catalytic converter and method for producing catalytic converter holding material
CN102762832A (en) * 2010-02-09 2012-10-31 霓佳斯株式会社 Retaining material for catalyst converter and manufacturing method of same
JP2011208519A (en) * 2010-03-29 2011-10-20 Nichias Corp Holding material for catalytic converter, and method of manufacturing the same
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