JP4691289B2

JP4691289B2 - Catalyst muffler

Info

Publication number: JP4691289B2
Application number: JP2001296103A
Authority: JP
Inventors: 暁光王
Original assignee: Tokyo Roki Co Ltd
Current assignee: Tokyo Roki Co Ltd
Priority date: 2001-09-27
Filing date: 2001-09-27
Publication date: 2011-06-01
Anticipated expiration: 2021-09-27
Also published as: JP2003097260A

Description

【０００１】
【発明の属する技術分野】
この発明は、各種担体が触媒層を担持してなる排気ガス浄化触媒をその内部に備えて内燃機関の排気ガスを適宜浄化する触媒マフラに関し、特にその内部に補強プレートを備えるものに関する。
【０００２】
【従来の技術】
環境保全に対する認識の高まりや従来からの排気ガス規制措置に呼応するように、排気ガス浄化用の触媒やこれを備えた触媒マフラが種々開発されてきた。この触媒マフラは、例えばハニカム状に形成した金属系などの各種担体が貴金属等の触媒層を担持してなる排気ガス浄化触媒をその内部に備え、この触媒層でもって内燃機関の排気ガスに含まれる除去対象成分を取り込んで排気ガス浄化を実現するものであり、例えば図１に示すような基本構造を備えている。ここにおける触媒マフラ１０の構造は、略円筒形の胴体１１と、この胴体１１の内空を前室１２と後室１３とに区画して排気ガスの浄化を担う排気ガス浄化触媒１４と、この排気ガス浄化触媒１４をはさんで隔壁状に設置され触媒マフラ１０や排気ガス浄化触媒１４に作用する各種応力を支持し負担する補強プレート１５とから主に構成される。
【０００３】
【発明が解決しようとする課題】
しかし従来の触媒マフラにおいては、補強プレート１５の周縁Ａの全てと胴体１１内周とが溶接部位１６によりゆるぎなく固定されており、触媒マフラ１０に作用する各種応力を剛的に支持することは出来ても、自身に作用した応力をキャンセルすることは難しかった。例えば、触媒マフラ１０に通じる排気ガスが高温となっている場合に、補強プレート１５と胴体１１との温度差から応力が発生し、これが補強プレート１５に作用する状況が考えられる。当該補強プレート１５は、周縁Ａが全て胴体１１内周と固定されていて応力を逃すすべがないため、自身に作用した応力に由来する変形や破損、前記溶接部位１６の破断などが発生するおそれがあった。これらの問題は触媒マフラ１０の破損や、それによる排気ガス漏れ、騒音増大などのトラブルを引き起こしかねず解決が待たれていた。
【０００４】
本発明はこのような事情に鑑みてなされたものであり、胴体との温度差により生じる熱膨張や収縮に由来する応力を吸収可能な補強プレートを備える触媒マフラを提供するものである。
【０００５】
【課題を解決するための手段】
この発明は上記目的を達成するためになされたもので、各種担体が触媒層を担持してなる排気ガス浄化触媒をその内部に備えて内燃機関の排気ガスを適宜浄化する触媒マフラであって、前記触媒マフラ胴体内において排気ガス浄化触媒をはさんで隔壁状に設置され、触媒マフラや排気ガス浄化触媒に作用する各種応力を支持し負担する補強プレートの周縁が、前記触媒マフラの胴体内周のうち所定の周位置にだけ栓溶接でもって間欠的に固定されてなり、かつ、栓溶接部位から触媒マフラの胴心に向け延びる補強プレート周縁が触媒マフラの胴体内周と所定の離隔距離を保って屈曲してなることを特徴とする。
【０００６】
上記発明において、前記所定の周位置に溶接固定された前記補強プレート周縁における溶接部位の両端に、所定幅を持った切込み箇所を設けることが好ましい。
【０００８】
【発明の実施の形態】
本実施形態において、触媒マフラに発生する熱応力とそれに由来する変形量とをモデルを用いて解析し、その解析結果と併せて本発明の触媒マフラについて説明することとする。ここで用いるモデル用の触媒マフラは、図１に示す触媒マフラと同様の基本構造を備えるものであり、胴体内径を２５４ｍｍとしている。以下に、その解析条件を示す。
【０００９】
＝＝＝解析条件＝＝＝
１．温度条件：
▲１▼ＴＩ用マフラは最高内部ガス温度５５８℃、胴体温度３６８℃
▲２▼ＮＡ用マフラは最高内部ガス温度７５８℃、胴体温度５１４℃
▲３▼なお、水冷時にはＴＩ用およびＮＡ用の胴体温度ともに１００℃
２．使用材料：フェライト系ステンレス
【００１０】
＝＝＝熱応力の算定＝＝＝
触媒マフラ胴体の温度Ｔoと補強プレートの温度Ｔpとの温度差による熱膨張ミスマッチによる補強プレートの周縁にかかる応力ｐiは、
▲１▼ＴＩ用ｐi＝Ｅα_Ｅ（Ｔp−Ｔo）
＝１６２００×１２．４×１０^−６（５５８−３８０）
＝３５．８（ｋｇ／ｍｍ^２）
＞σ_ａ＝８．３ｋｇ／ｍｍ^２（４２５゜Ｃで）
▲２▼ＮＡ用ｐi＝Ｅα_Ｅ（Ｔp−Ｔo）
＝１３５００×１２．４×１０^−６（７５８−５１４）
＝４０．８（ｋｇ／ｍｍ^２）
＞σ_ａ＝４．８ｋｇ／ｍｍ^２（５４０゜Ｃで）
【００１１】
また、Ｌａｍｅの式から、外圧のみを受ける円筒（ここでは触媒マフラの胴体にあたる）にかかる応力は、
【００１２】
【イメージ１】

となる。
【００１３】
この式１に基づいて上記条件をＴＩ用およびＮＡ用いずれに適用しても、補強プレートへ負荷される応力が許容値を超えてしまう。つまり、通常想定される触媒マフラの使用条件において、補強プレートに何らかの措置が施されない場合、許容値以上の応力が負荷され続けることが予想される。いずれは変形、破損、破断等の発生が危惧されるところである。
【００１４】
＝＝＝本発明の触媒マフラについて＝＝＝
図２は本発明の触媒マフラーにおける補強プレート１５と胴体１１との固定構造を示す説明図である。上述のような解析結果を受けて、本発明の触媒マフラ１０においては補強プレート１５に作用する応力を逃す構造が採用される。例えば、補強プレート１５の周縁Ａを、触媒マフラ１０の胴体１１内周のうち所定の周位置にだけ間欠的に溶接固定した構造を採用することとした。この構造は図２（ｂ）に示すように、補強プレート周縁Ａを全周にわたって胴体１１内周と溶接せず、特定の溶接部位２１のみにおいて溶接固定する構造となっている。このように適宜な間隔を設けて溶接固定すると共に、その溶接方法も栓溶接とすれば好適である。
【００１５】
また更に、溶接固定した前記補強プレート１５の周縁Ａにおける溶接部位２１の両端に、所定幅χを持った切込み箇所１６を設ける。これら、胴体１１の内周と溶接固定されていない補強プレート周縁Ａと切り込み箇所１６とは、胴体１１の円周方向に作用する熱膨張や熱収縮に応じて自身を変形させ吸収することから、補強プレート１５はあたかも伸縮継手を備えたのと同様の機能を持つことになるのである。
【００１６】
加えて図２（ａ）に示すように、前記栓溶接部位２１から触媒マフラ１０の胴心に向け延びる補強プレート周縁Ａが触媒マフラ１０の胴体内周と所定の離隔距離μを保って屈曲してなることとすれば、この離隔距離μの分だけ補強プレート１５は変形余裕を持つことができる。すなわち、触媒マフラ１０の胴体１１の直径方向に作用する熱膨張や熱収縮を、この離隔距離μの屈曲構造により吸収することが可能となるのである。詳細な計算結果はここでは省略するが、上述と同じ解析条件において同じ解析式を利用して応力計算等を行ったところ、本発明の触媒マフラに関しては、作用する応力が許容値におさまり、勿論、熱膨張や収縮に由来する変形量等も許容値に留まる優れた結果が得られた。
【００１７】
【発明の効果】
以上説明したように本発明の触媒マフラは、触媒マフラに作用する各種応力を剛的に支持することが出来るとともに、自身に作用した応力をキャンセルすることも可能な補強プレートを備えることにより、例えば胴体と補強プレートとの温度差に由来する熱膨張応力や熱収縮応力をキャンセルすることができる。そのため、従来危惧されていた補強プレートの変形や破損、胴体内周との溶接部位の破断などが生じるおそれは解消される。そして、これら補強プレートの変形や破損等の問題が解消されることで、触媒マフラの破損や、排気ガス漏れ、騒音増大などの発生も抑制されることとなった。
【００１８】
従って、胴体との温度差により生じる熱膨張や収縮に由来する応力を吸収可能な補強プレートを備える触媒マフラを提供可能となる。
【図面の簡単な説明】
【図１】触媒マフラーの基本構造を示す^{説明図である。}
【図２】本発明の触媒マフラーにおける補強プレートと胴体との固定構造を示す説明図である。
【符号の説明】
Ａ補強プレート周縁
１０触媒マフラ
１１触媒マフラ胴体
１４排気ガス浄化触媒
１５補強プレート[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a catalyst muffler that includes an exhaust gas purifying catalyst in which various carriers carry a catalyst layer therein and purifies the exhaust gas of an internal combustion engine as appropriate, and particularly relates to a catalyst muffler that includes a reinforcing plate therein.
[0002]
[Prior art]
Various catalysts for exhaust gas purification and catalyst mufflers equipped with the same have been developed in response to the growing awareness of environmental conservation and conventional exhaust gas regulation measures. This catalyst muffler includes an exhaust gas purification catalyst in which various carriers, such as a metal system formed in a honeycomb shape, carry a catalyst layer such as a noble metal, and is contained in the exhaust gas of the internal combustion engine with this catalyst layer. The component to be removed is taken in and exhaust gas purification is realized, and for example, has a basic structure as shown in FIG. The structure of the catalyst muffler 10 here includes a substantially cylindrical body 11, an exhaust gas purification catalyst 14 for purifying exhaust gas by dividing the inner space of the body 11 into a front chamber 12 and a rear chamber 13, It is mainly composed of a reinforcing plate 15 that is installed in a partition shape across the exhaust gas purification catalyst 14 and supports and bears various stresses acting on the catalyst muffler 10 and the exhaust gas purification catalyst 14.
[0003]
[Problems to be solved by the invention]
However, in the conventional catalyst muffler, all of the peripheral edge A of the reinforcing plate 15 and the inner periphery of the fuselage 11 are securely fixed by the welded portion 16, and it is possible to rigidly support various stresses acting on the catalyst muffler 10. Even if it was possible, it was difficult to cancel the stress acting on itself. For example, when the exhaust gas leading to the catalyst muffler 10 is at a high temperature, a situation in which stress is generated from the temperature difference between the reinforcing plate 15 and the body 11 and this acts on the reinforcing plate 15 can be considered. Since the reinforcing plate 15 has all the periphery A fixed to the inner periphery of the body 11 and cannot release stress, there is a risk that deformation or breakage due to the stress acting on itself or breakage of the welded part 16 may occur. was there. These problems could cause troubles such as damage to the catalyst muffler 10, exhaust gas leakage and increased noise, and awaiting a solution.
[0004]
This invention is made | formed in view of such a situation, and provides a catalyst muffler provided with the reinforcement plate which can absorb the stress originating in the thermal expansion and shrinkage which arise by a temperature difference with a fuselage | body.
[0005]
[Means for Solving the Problems]
The present invention has been made in order to achieve the above object, a catalyst muffler appropriately purifying exhaust gas of an internal combustion engine provided with an exhaust gas purification catalyst in which various carrier formed by loading a catalyst layer therein, The catalyst muffler body is installed in the form of a partition across the exhaust gas purification catalyst, and the periphery of the reinforcing plate that supports and bears various stresses acting on the catalyst muffler and the exhaust gas purification catalyst is the periphery of the catalyst muffler body. The peripheral edge of the reinforcing plate, which is intermittently fixed by plug welding only at a predetermined circumferential position , and extends from the plug welding portion toward the center of the catalyst muffler has a predetermined separation distance from the inner periphery of the body of the catalyst muffler. It is characterized by being bent while maintaining .
[0006]
In the above invention, both ends of the welded part in the predetermined circumferential said reinforcing plate peripheral edge which is welded to a position, preferably Rukoto provided a notch portion having a predetermined width.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the present embodiment, the thermal stress generated in the catalyst muffler and the deformation amount derived therefrom are analyzed using a model, and the catalyst muffler of the present invention will be described together with the analysis result. The model catalyst muffler used here has the same basic structure as that of the catalyst muffler shown in FIG. 1, and has a fuselage inner diameter of 254 mm. The analysis conditions are shown below.
[0009]
=== Analysis conditions ===
1. Temperature conditions:
(1) TI muffler has maximum internal gas temperature of 558 ° C and fuselage temperature of 368 ° C
(2) The NA muffler has a maximum internal gas temperature of 758 ° C and a fuselage temperature of 514 ° C.
(3) The body temperature for both TI and NA is 100 ° C during water cooling.
2. Material used: Ferritic stainless steel [0010]
=== Calculation of thermal stress ===
The stress pi applied to the periphery of the reinforcing plate due to thermal expansion mismatch due to the temperature difference between the temperature To of the catalyst muffler body and the temperature Tp of the reinforcing plate is
(1) For TI pi = Eα _E (Tp-To)
= 16200 × 12.4 × 10 ⁻⁶ (558-380)
= 35.8 (kg / mm ² )
> Σ _a = 8.3 kg / mm ² (at 425 ° C.)
(2) For NA pi = Eα _E (Tp-To)
= 13500 × 12.4 × 10 ⁻⁶ (758-514)
= 40.8 (kg / mm ² )
> Σ _a = 4.8 kg / mm ² (at 540 ° C.)
[0011]
Further, from the Lame equation, the stress applied to the cylinder that receives only the external pressure (here, the body of the catalyst muffler) is:
[0012]
[Image 1]

It becomes.
[0013]
Regardless of whether the above condition is applied to TI or NA based on Equation 1, the stress applied to the reinforcing plate exceeds the allowable value. That is, it is expected that stress exceeding the allowable value will continue to be applied if any measures are not applied to the reinforcing plate under the normally assumed conditions for using the catalyst muffler. In any case, the occurrence of deformation, breakage, breakage, etc. is a concern.
[0014]
=== About the catalyst muffler of the present invention ===
FIG. 2 is an explanatory view showing a fixing structure between the reinforcing plate 15 and the body 11 in the catalyst muffler of the present invention. In response to the analysis results as described above, the catalyst muffler 10 of the present invention employs a structure that releases stress acting on the reinforcing plate 15. For example, a structure in which the peripheral edge A of the reinforcing plate 15 is intermittently welded and fixed only at a predetermined peripheral position on the inner periphery of the body 11 of the catalyst muffler 10 is adopted. As shown in FIG. 2B, this structure is such that the reinforcing plate peripheral edge A is not welded to the inner periphery of the body 11 over the entire periphery, and is welded and fixed only at a specific welding site 21. As described above, it is preferable that the welding is fixed at an appropriate interval and the welding method is plug welding.
[0015]
Furthermore, cut portions 16 having a predetermined width χ are provided at both ends of the welded portion 21 at the peripheral edge A of the reinforcing plate 15 fixed by welding. The inner periphery of the body 11 and the reinforcing plate peripheral edge A and the cut portion 16 that are not fixed by welding are deformed and absorbed according to thermal expansion and contraction acting in the circumferential direction of the body 11. The reinforcing plate 15 has the same function as if it had an expansion joint.
[0016]
In addition, as shown in FIG. 2A, the peripheral edge A of the reinforcing plate extending from the plug welded portion 21 toward the core of the catalyst muffler 10 is bent with a predetermined separation distance μ from the periphery of the body of the catalyst muffler 10. As a result, the reinforcing plate 15 can have a deformation margin by the distance μ. That is, the thermal expansion and contraction acting in the diameter direction of the body 11 of the catalyst muffler 10 can be absorbed by the bent structure having the separation distance μ. Although detailed calculation results are omitted here, when stress calculation is performed using the same analytical expression under the same analysis conditions as described above, the stress acting on the catalyst muffler of the present invention falls within an allowable value, of course. Further, excellent results were obtained in which the deformation amount derived from thermal expansion and contraction remained at an allowable value.
[0017]
【The invention's effect】
As described above, the catalyst muffler of the present invention includes a reinforcing plate capable of rigidly supporting various stresses acting on the catalyst muffler and canceling the stress acting on the catalyst muffler. Thermal expansion stress and thermal contraction stress derived from the temperature difference between the body and the reinforcing plate can be canceled. Therefore, the fear of the deformation and breakage of the reinforcing plate and the breakage of the welded portion with the inner periphery of the body have been solved. And since problems such as deformation and breakage of these reinforcing plates were eliminated, the occurrence of breakage of the catalyst muffler, leakage of exhaust gas, increase in noise, etc. was suppressed.
[0018]
Therefore, it is possible to provide a catalyst muffler including a reinforcing plate capable of absorbing stress resulting from thermal expansion and contraction caused by a temperature difference with the body.
[Brief description of the drawings]
FIG. 1 is an ^{explanatory view} showing a basic structure of a catalyst muffler ^.
FIG. 2 is an explanatory view showing a fixing structure between a reinforcing plate and a body in a catalyst muffler of the present invention.
[Explanation of symbols]
A Reinforcement plate peripheral edge 10 Catalyst muffler 11 Catalyst muffler body 14 Exhaust gas purification catalyst 15 Reinforcement plate

Claims

A catalyst muffler for appropriately purifying exhaust gas of an internal combustion engine by providing an exhaust gas purification catalyst in which various carriers carry a catalyst layer in its interior,
The catalyst muffler body is installed in the form of a partition across the exhaust gas purification catalyst, and the periphery of the reinforcing plate that supports and bears various stresses acting on the catalyst muffler and the exhaust gas purification catalyst is the periphery of the catalyst muffler body. And is fixed intermittently by plug welding only at a predetermined circumferential position , and
A catalyst muffler characterized in that a peripheral edge of a reinforcing plate extending from a plug welded portion toward a core of the catalyst muffler is bent with a predetermined separation distance from a periphery of the body of the catalyst muffler.

2. The catalyst muffler according to claim 1, wherein cut portions having a predetermined width are provided at both ends of a welded portion at a periphery of the reinforcing plate fixed by welding at the predetermined circumferential position.