JP4331816B2

JP4331816B2 - Exhaust gas purification device

Info

Publication number: JP4331816B2
Application number: JP06958099A
Authority: JP
Inventors: 正行岩田; 功東垣外
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 1999-03-16
Filing date: 1999-03-16
Publication date: 2009-09-16
Anticipated expiration: 2019-03-16
Also published as: JP2000265829A

Description

【０００１】
【発明の属する技術分野】
本発明は、多気筒エンジンから延びる複数の排気管の下流側に排気ガスの通路断面積が増大する排気膨張部を形成し、この排気膨張部に排気ガスを浄化する触媒コンバータを配置した排気ガス浄化装置に関する。
【０００２】
【従来の技術】
自動二輪車の多気筒エンジンから延びる複数の排気管を排気集合管で束ね、その排気集合管にジョイント管を介して接続したマフラーの内部に触媒コンバータを配置した排気ガス浄化装置が、特開平１０−１０３０４６号公報により公知である。このように、排気ガスの通路断面積が増大する排気膨張部であるマフラーの内部に触媒コンバータを配置することにより、触媒コンバータによる排気ガスの流通抵抗の増加を低く抑えてエンジン出力の低下を回避することができる。
【０００３】
【発明が解決しようとする課題】
しかしながら上記従来のものは、触媒コンバータが触媒を担持したプレートを渦巻き状に巻き付けたハニカムプレートから構成されており、その触媒コンバータがマフラー内を流れる排気ガスの流路を完全に遮るように配置されているため、排気ガスの流通抵抗の増加を充分に低く抑えることが難しいという問題があった。
【０００４】
本発明は前述の事情に鑑みてなされたもので、触媒コンバータによる排気ガスの流通抵抗の増加を最小限に抑えながら充分な排気ガス浄化効果を発揮することが可能な排気ガス浄化装置を提供することを目的とする。
【０００５】
【課題を解決するための手段】
上記目的を達成するために、請求項１に記載された発明によれば、多気筒エンジンから延びる４本の排気管の下流端を、それら下流端の軸線がこれと直交する断面で見て正方形の四隅に位置するようにして相互に隣接配置すると共に、それら４本の排気管の下流端に、それら下流端を集合させる１つの排気膨張部を、それら下流端の集合部において排気ガスの通路断面積が増大するように連設し、この排気膨張部の内部には、排気ガスを浄化する触媒コンバータを配置し、前記排気膨張部は、上流側から下流側に向けて外径が縮小する筒状の部材で形成されていて、４個の半円を円周方向に９０°間隔で並べた異形断面を有して４本の排気管に接続される上流端から、円形断面を有して１本の排気集合管に接続される下流端に向けて断面形状が滑らかに変化しており、且つ該排気膨張部の中間部の内壁面が、前記異形断面に対応して４つの横断面半円状の凹面を有している排気ガス浄化装置であって、前記触媒コンバータを、径方向内外を排気ガスが通過し得るパイプ状に形成し、かつ排気ガスが流れる方向に軸線を沿わせて配置すると共に、１個の取付ステーで該触媒コンバータを前記排気膨張部に支持し、前記取付ステーを、前記軸線と直交する横断面で見て波形に形成される板体から構成して、その取付ステーの両端部を前記排気膨張部の中間部の内壁面の異なる２つの前記凹面にそれぞれ沿うように形成して、該２つの凹面にそれぞれ溶接すると共に、またその取付ステーの中間部を前記触媒コンバータに固定し、前記触媒コンバータの上流端が前記複数の排気管の下流端近傍に達していると共に、その触媒コンバータの下流端が前記排気集合管の内部に所定距離だけ突出していることを特徴とする排気ガス浄化装置が提案される。
【０００６】
上記構成によれば、４本の排気管の下流側に形成された、排気ガスの通路断面積が増大する排気膨張部に触媒コンバータを配置したので、その触媒コンバータによる排気ガスの流通抵抗の増加を最小限に抑えることができる。しかも触媒コンバータを、径方向内外を排気ガスが通過し得るパイプ状に形成して排気ガスが流れる方向に軸線を沿わせて配置したことにより、排気ガスのスムーズな流れを可能にして排気ガスの流通抵抗を更に効果的に低減することができるだけでなく、触媒コンバータに排気ガスを効果的に接触させて浄化効率を高めることができる。
【０００７】
また請求項２に記載された発明によれば、請求項１の構成に加えて、前記触媒コンバータの外周面が、円筒状に形成された２個のインナーホルダに嵌合して摺動可能に支持されると共に、そのインナーホルダの半径方向外側には、断面半円状に形成された２個のアウターホルダが嵌合、固定され、それらインナーホルダ及びアウターホルダ間にスチールウールが充填され、前記２個のアウターホルダーに前記取付ステーの中間部が溶接されることで、前記触媒コンバータが該取付ステーの中間部に固定されることを特徴とする排気ガス浄化装置が提案される。
【０００８】
【発明の実施の形態】
以下、本発明の実施形態を、添付図面に示した参考例及び本発明の実施例に基づいて説明する。
【０００９】
図１〜図５は参考例を示すもので、図１は排気ガス浄化装置を備えた自動二輪車の全体側面図、図２は図１の２部拡大断面図、図３は図２の３−３線断面図、図４は図２の４−４線断面図、図５は図４の５−５線断面図である。
【００１０】
図１に示すように、自動二輪車Ｖは操向ハンドル１１に接続されたフロントフォーク１２の下端に軸支された前輪Ｗｆと、リヤクッション１３により上下揺動自在に枢支されたリヤフォーク１４の後端に軸支された後輪Ｗｒとを備えており、この後輪Ｗｒは車体中央部に搭載されたパワーユニットＰによりチェーン１５を介して駆動される。パワーユニットＰは４気筒のエンジンＥとトランスミッションＴとを一体に備えるもので、シリンダ軸線を前上方に傾斜させたエンジンＥのシリンダヘッド下面から４本の排気管１６…が前下方に延出する。４本の排気管１６…は後方に向けて屈曲し、トランスミッションＴの下方の排気膨張部１７において集合する。排気膨張部１７において１本に集合した排気集合管１８は上方に立ち上がった後に後上方に屈曲し、車体の後部右側面に配置されたマフラー１９に接続される。
【００１１】
図２〜図５に示すように、排気膨張部１７の上流位置で一体に束ねられた４本の排気管１６…の各々は、カラー２１を介して同軸に配置されたアウターパイプ２２およびインナーパイプ２３よりなる２重管構造を備えており、両パイプ２２，２３間に空間２４を形成して排気ガスの温度低下の防止を図っている。９０°間隔で束ねられた４本の排気管１６…の間に形成される空間は、それらに溶接Ｗ₃で固定された閉塞板２５により閉塞される。
【００１２】
排気膨張部１７は、上流側から下流側に向けて外径が縮小する筒状の部材であって、４個の半円を円周方向に９０°間隔で配置した異形断面を有して４本の排気管１６…に溶接Ｗ₁により接続される上流端から、円形断面を有して１本の排気集合管１８に接続される下流端に向けて、その断面形状が滑らかに変化している。排気膨張部１７の内部に配置された触媒コンバータ２６は、多数のパンチング孔２６₁…が形成されたパイプ状の触媒担体の全表面に白金やロジウム等の触媒を担持したものから構成される。触媒コンバータ２６の軸線Ｌは排気膨張部１７の内部における排気ガスの流れ方向に沿うように配置されており、その上流端は４本の排気管１６…の下流端の近傍に達しており、その下流端は排気膨張部１７に溶接Ｗ₂により接続された排気集合管１８の内部に距離Ａだけ突出している。
【００１３】
排気膨張部１７における排気ガスの通路断面積は、４本の排気管１６…の通路断面積の総和よりも大きく、かつ１本の排気集合管１８の通路断面積よりも大きくなっている。従って、排気膨張部１７を流れる排気ガスの流速は、排気管１６…あるいは排気集合管１８を流れる排気ガスの流速よりも小さくなる。
【００１４】
触媒コンバータ２６の外周面は、円筒状に形成された２個のインナーホルダ２７，２７に嵌合して摺動自在に支持されており、その半径方向外側に断面半円状に形成された２個のアウターホルダ２８，２８が嵌合して溶接Ｗ₄により固定され、更に前記インナーホルダ２７，２７およびアウターホルダ２８，２８間にスチールウール２９が充填される。排気膨張部１７の上流端近傍の内周面に、即ち４本の排気管１６…の下流端に隣接する位置に一対の取付ステー３０，３０が溶接Ｗ₅により固定される。
【００１５】
各取付ステー３０の上流端の断面は排気膨張部１７の内面形状に沿うように２個の円弧を接続した形状を有しており、そこから断面形状が半円状に変化した下流側部分が、前記アウターホルダ２８の外周面に溶接Ｗ₆により固定されるとともに、アウターホルダ２８およびインナーホルダ２７，２７に溶接Ｗ₇により固定される。そして取付ステー３０の中間部に２個の通孔３０₁，３０₁が形成される。
【００１６】
次に、前述の構成を備えた参考例の作用について説明する。
【００１７】
多気筒のエンジンＥのシリンダヘッドから４本の排気管１６…に排出された排気ガスは、一体に束ねられた排気管１６…の下流端から排気膨張部１７の上流端に流入する。排気膨張部１７に流入した排気ガスの一部がパイプ状の触媒コンバータ２６の内側を流れ、また他の一部が２個の取付ステー３０，３０の間の空間あるいは該取付ステー３０，３０の通孔３０₁…を通過して触媒コンバータ２６の外側を流れ、更に排気ガスが触媒コンバータ２６の径方向内外一側から多数のパンチング孔２６…を通過して径方向内外他側に移動するように流れる間に、触媒コンバータ２６の表面に担持した触媒に接触して浄化される。そして浄化された排気ガスは、排気集合管１８およびマフラー１９を経て大気に排出される。
【００１８】
このように、４本の排気管１６…の下流側に接続されて通路断面積が増加する排気膨張部１７に触媒コンバータ２６を配置するとともに、その触媒コンバータ２６をパイプ状に形成して排気ガスの流れる方向に沿うように配置したので、触媒コンバータ２６による排気ガスの流通抵抗の増加を低く抑えてエンジン出力の低下を防止することが可能になる。また触媒コンバータ２６は多数のパンチング孔２６₁…を備えているために触媒の担持面積が増加し、しかも排気ガスの流れを一部阻止する取付ステー３０，３０によって触媒コンバータ２６の径方向内外一側および他側間の排気ガスの流通が促進されるため、排気ガスを触媒に効果的に接触させて浄化効率を高めることができる。更に、触媒コンバータ２６の一部が排気集合管１８の内部に延びているため、排気ガスを排気膨張部１７から排気集合管１８にスムーズに導いて流通抵抗を低減することができる。
【００１９】
取付ステー３０，３０が固定される排気膨張部１７の上流端近傍は４本の排気管１６…の結合によって剛性が高められており、かつ取付ステー３０，３０自体も湾曲した断面形状によって高い曲げ剛性を有するため、取付ステー３０，３０による触媒コンバータ２６の取付剛性を充分に高めることができる。
【００２０】
次に、図６および図７に基づいて本発明の実施例を説明する。
【００２１】
上述した参考例では２個の取付ステー３０，３０によって触媒コンバータ２６を排気膨張部１７に支持していたが、本実施例では触媒コンバータ２６が１個の取付ステー３１によって排気膨張部１７に支持される。取付ステー３１は断面波形に形成された板体から構成されており、その両端部を排気膨張部１７の内壁面に溶接Ｗ₈により固定するとともに、その中間部を触媒コンバータ２６を保持する２個のアウターホルダー２８，２８に溶接Ｗ₉により固定することにより、触媒コンバータ２６が排気膨張部１７に支持される。
【００２２】
この排気膨張部１７の中間部の内壁面は、その上流端の、４個の半円を周方向に並べた前記異形断面に対応して周方向に並ぶ４つの横断面半円状の凹面を有しており、前記取付ステー３１の両端部は、排気膨張部１７の中間部の内壁面の異なる２つの前記凹面にそれぞれ沿うように形成されていて、該２つの凹面にそれぞれ溶接Ｗ ₈ される。
【００２３】
この実施例によれば、取付ステー３１が１個で済むために部品点数が減少するだけでなく、取付ステー３１が排気ガスの流れ方向に対して略平行に配置されていることと相俟って、排気ガスの流通抵抗を更に低減することができる。
【００２４】
以上、参考例及び本発明の実施例を詳述したが、本発明はその要旨を逸脱しない範囲で種々の設計変更を行うことが可能である。
【００２５】
例えば、実施例では排気膨張部１７において４本の排気管１６…を集合させているが、集合させる排気管１６…の数は４本に限定されるのではない。
【００２６】
【発明の効果】
以上のように請求項１に記載された発明によれば、複数の排気管の下流側に形成された排気ガスの通路断面積が増大する排気膨張部に触媒コンバータを配置したので、その触媒コンバータによる排気ガスの流通抵抗の増加を最小限に抑えることができる。しかも触媒コンバータを、径方向内外を排気ガスが通過し得るパイプ状に形成して排気ガスが流れる方向に軸線を沿わせて配置したことにより、排気ガスのスムーズな流れを可能にして排気ガスの流通抵抗を更に効果的に低減することができるだけでなく、触媒コンバータに排気ガスを効果的に接触させて浄化効率を高めることができる。また取付ステーを、前記軸線と直交する横断面で見て波形に形成される板体から構成して、その取付ステーの両端部を排気膨張部の内壁面に、またその取付ステーの中間部を触媒コンバータにそれぞれ固定したので、取付ステーが１個で済むために部品点数が減少するだけでなく、取付ステーが排気ガスの流れ方向に対して略平行に配置されていることと相俟って、排気ガスの流通抵抗を更に低減することができる。
【図面の簡単な説明】
【図１】参考例に係る排気ガス浄化装置を備えた自動二輪車の全体側面図
【図２】図１の２部拡大断面図
【図３】図２の３−３線断面図
【図４】図２の４−４線断面図
【図５】図４の５−５線断面図
【図６】本発明の実施例に係る、前記図２に対応する図
【図７】図６の７−７線断面図
【符号の説明】
１６排気管
１７排気膨張部
２６触媒コンバータ
２７インナーホルダ
２８アウターホルダ
２９スチールウール
３１取付ステー
Ａ距離
Ｅエンジン
Ｌ軸線[0001]
BACKGROUND OF THE INVENTION
The present invention provides an exhaust gas expansion portion in which a passage sectional area of exhaust gas increases on the downstream side of a plurality of exhaust pipes extending from a multi-cylinder engine, and an exhaust gas in which a catalytic converter for purifying the exhaust gas is disposed in the exhaust gas expansion portion. The present invention relates to a purification device.
[0002]
[Prior art]
An exhaust gas purifying apparatus in which a plurality of exhaust pipes extending from a multi-cylinder engine of a motorcycle are bundled by an exhaust collecting pipe and a catalytic converter is disposed inside a muffler connected to the exhaust collecting pipe through a joint pipe is disclosed in Japanese Patent Laid-Open No. No. 103046. In this way, by arranging the catalytic converter inside the muffler, which is the exhaust expansion section where the exhaust gas passage cross-sectional area increases, the increase in exhaust gas flow resistance by the catalytic converter is kept low, and the engine output is prevented from decreasing. can do.
[0003]
[Problems to be solved by the invention]
However, the above-mentioned conventional one is composed of a honeycomb plate in which a catalytic converter carries a plate carrying a catalyst in a spiral shape, and the catalytic converter is arranged so as to completely block an exhaust gas flow path in the muffler. Therefore, there has been a problem that it is difficult to suppress the increase in exhaust gas flow resistance sufficiently low.
[0004]
The present invention has been made in view of the above circumstances, and provides an exhaust gas purification device capable of exhibiting a sufficient exhaust gas purification effect while minimizing an increase in exhaust gas flow resistance by a catalytic converter. For the purpose.
[0005]
[Means for Solving the Problems]
To achieve the above object, according to the first aspect of the present invention, the downstream ends of the four exhaust pipes extending from the multi-cylinder engine are square when viewed in a cross section in which the axes of the downstream ends are orthogonal thereto. Are arranged adjacent to each other so as to be located at the four corners of the four exhaust pipes, and at the downstream end of the four exhaust pipes, one exhaust expansion portion for collecting the downstream ends is provided, and an exhaust gas passage at the collection portion of the downstream ends. A catalytic converter for purifying exhaust gas is arranged inside the exhaust expansion portion so as to increase the cross-sectional area. The outer diameter of the exhaust expansion portion decreases from the upstream side toward the downstream side. It has a circular cross section from the upstream end that is formed of a cylindrical member, has an irregular cross section in which four semicircles are arranged at intervals of 90 ° in the circumferential direction, and is connected to four exhaust pipes. Cross-sectional shape toward the downstream end connected to one exhaust collecting pipe Smoothly has changed, and the inner wall surface of the intermediate portion of the exhaust expansion portion, and an exhaust gas purification device has four transverse faces semicircular concave surface corresponding to the profile cross-section, wherein The catalytic converter is formed in a pipe shape through which exhaust gas can pass in and out of the radial direction, and is disposed along the axis in the direction in which the exhaust gas flows, and the catalytic converter is connected to the exhaust expansion portion with a single mounting stay. The mounting stay is composed of a plate body that is formed in a waveform when viewed in a cross section orthogonal to the axis, and both end portions of the mounting stay are different from the inner wall surface of the intermediate portion of the exhaust expansion portion. formed along each of two of said concave surface is welded respectively to the two concave, also the intermediate portion of the mounting stay is fixed to the catalytic converter, the exhaust upstream end of the catalytic converter of the plurality Near the downstream end of the tube An exhaust gas purifying apparatus is proposed in which the downstream end of the catalytic converter protrudes by a predetermined distance into the exhaust collecting pipe .
[0006]
According to the above configuration, is formed on the downstream side of the four exhaust pipes, the cross-sectional area of the exhaust gas is disposed a catalytic converter in an exhaust expansion unit to increase, increase in the flow resistance of the exhaust gas by the catalytic converter Can be minimized. In addition, the catalytic converter is formed in a pipe shape that allows exhaust gas to pass inside and outside in the radial direction, and is arranged along the axis in the direction in which the exhaust gas flows, thereby enabling a smooth flow of the exhaust gas. Not only can the flow resistance be reduced more effectively, but also the exhaust gas can be effectively brought into contact with the catalytic converter to increase the purification efficiency.
[0007]
According to the invention described in claim 2, in addition to the structure of claim 1, the outer peripheral surface of the catalytic converter is slidable by fitting with two inner holders formed in a cylindrical shape. Two outer holders formed in a semicircular cross section are fitted and fixed to the outer side in the radial direction of the inner holder, and steel wool is filled between the inner holder and the outer holder. by the middle portion of the mounting stay to the two outer holders are welded, the exhaust gas purifying apparatus in which the catalytic converter is characterized in that it is fixed to the intermediate portion of the stay with said mounting is Ru been proposed.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below based on reference examples shown in the accompanying drawings and examples of the present invention.
[0009]
1 to 5 show reference examples. FIG. 1 is an overall side view of a motorcycle equipped with an exhaust gas purification device, FIG. 2 is an enlarged cross-sectional view of part 2 of FIG. 1, and FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2, and FIG. 5 is a cross-sectional view taken along line 5-5 of FIG.
[0010]
As shown in FIG. 1, the motorcycle V includes a front wheel Wf pivotally supported at the lower end of a front fork 12 connected to a steering handle 11, and a rear fork 14 pivotally supported by a rear cushion 13 so as to be swingable up and down. The rear wheel Wr is pivotally supported at the rear end, and the rear wheel Wr is driven via a chain 15 by a power unit P mounted at the center of the vehicle body. The power unit P integrally includes a four-cylinder engine E and a transmission T, and four exhaust pipes 16 extend forward and downward from the lower surface of the cylinder head of the engine E with the cylinder axis inclined forward and upward. The four exhaust pipes 16 are bent rearward and gather at the exhaust expansion portion 17 below the transmission T. The exhaust collecting pipe 18 gathered into one in the exhaust expanding portion 17 rises upward, then bends rearward and upward, and is connected to a muffler 19 disposed on the rear right side of the vehicle body.
[0011]
As shown in FIGS. 2 to 5, each of the four exhaust pipes 16... Bundled integrally at the upstream position of the exhaust expansion portion 17 is composed of an outer pipe 22 and an inner pipe arranged coaxially via a collar 21. A double pipe structure consisting of 23 is provided, and a space 24 is formed between both pipes 22 and 23 to prevent the temperature of the exhaust gas from decreasing. A space formed between the four exhaust pipes 16 bundled at intervals of 90 ° is closed by a closing plate 25 fixed to them by welding W ₃ .
[0012]
The exhaust expansion part 17 is a cylindrical member whose outer diameter decreases from the upstream side toward the downstream side, and has an irregular cross section in which four semicircles are arranged at intervals of 90 ° in the circumferential direction. The cross-sectional shape changes smoothly from the upstream end connected to the _single exhaust pipe 16 to the downstream end connected to the single exhaust collecting pipe 18 from the upstream end connected to the exhaust pipe 16 by welding W _1. Yes. The catalytic converter 26 disposed inside the exhaust expansion part 17 is configured by carrying a catalyst such as platinum or rhodium on the entire surface of a pipe-shaped catalyst carrier having a number of punching holes 26 ₁ . The axis L of the catalytic converter 26 is arranged along the flow direction of the exhaust gas inside the exhaust expansion portion 17, and its upstream end reaches the vicinity of the downstream ends of the four exhaust pipes 16. a downstream end which projects into the interior of the weld W ₂ by connecting exhaust collecting pipe 18 into the exhaust expansion portion 17 by a distance a.
[0013]
The exhaust gas passage cross-sectional area in the exhaust expansion portion 17 is larger than the sum of the passage cross-sectional areas of the four exhaust pipes 16... And larger than the passage cross-sectional area of one exhaust collecting pipe 18. Therefore, the flow rate of the exhaust gas flowing through the exhaust expansion portion 17 is smaller than the flow rate of the exhaust gas flowing through the exhaust pipes 16.
[0014]
The outer peripheral surface of the catalytic converter 26 is slidably supported by being fitted to two cylindrical inner holders 27, 27, and is formed in a semicircular cross section on the radially outer side. The outer holders 28 and 28 are fitted and fixed by welding W _4, and steel wool 29 is filled between the inner holders 27 and 27 and the outer holders 28 and 28. A pair of mounting stays 30 and 30 are fixed to the inner peripheral surface near the upstream end of the exhaust expansion portion 17, that is, at positions adjacent to the downstream ends of the four exhaust pipes 16 by welding W ₅ .
[0015]
The cross section of the upstream end of each mounting stay 30 has a shape in which two arcs are connected so as to follow the inner surface shape of the exhaust expansion portion 17, and the downstream portion from which the cross-sectional shape has changed to a semicircular shape is formed. The outer holder 28 is fixed to the outer peripheral surface by welding W ₆ and is fixed to the outer holder 28 and the inner holders 27 and 27 by welding W ₇ . Two through holes 30 ₁ and 30 ₁ are formed in the intermediate portion of the mounting stay 30.
[0016]
Next, the operation of the reference example having the above-described configuration will be described.
[0017]
The exhaust gas discharged from the cylinder head of the multi-cylinder engine E to the four exhaust pipes 16 flows into the upstream end of the exhaust expansion portion 17 from the downstream end of the exhaust pipes 16 bundled together. Part of the exhaust gas flowing into the exhaust expansion part 17 flows inside the pipe-shaped catalytic converter 26, and the other part is a space between the two attachment stays 30, 30 or the attachment stays 30, 30. The exhaust gas passes through the through holes 30 ₁ ... And flows outside the catalytic converter 26, and the exhaust gas moves from the radially inner and outer sides of the catalytic converter 26 through the numerous punching holes 26 to the radially inner and outer sides. During the flow, the catalyst is carried on the surface of the catalytic converter 26 to be purified. The purified exhaust gas is discharged to the atmosphere through the exhaust collecting pipe 18 and the muffler 19.
[0018]
As described above, the catalytic converter 26 is disposed in the exhaust expansion portion 17 connected to the downstream side of the four exhaust pipes 16 and having an increased passage cross-sectional area, and the catalytic converter 26 is formed in a pipe shape to form exhaust gas. Therefore, the increase in the exhaust gas flow resistance by the catalytic converter 26 can be kept low, and the engine output can be prevented from decreasing. Further, since the catalytic converter 26 is provided with a number of punching holes 26 ₁ ..., The catalyst carrying area is increased, and the mounting stays 30 and 30 that partially block the flow of the exhaust gas are used for the inner and outer diameters of the catalytic converter 26. Since the flow of the exhaust gas between the side and the other side is promoted, the exhaust gas can be effectively brought into contact with the catalyst to increase the purification efficiency. Further, since a part of the catalytic converter 26 extends into the exhaust collecting pipe 18, the exhaust gas can be smoothly guided from the exhaust expanding portion 17 to the exhaust collecting pipe 18 to reduce the flow resistance.
[0019]
The vicinity of the upstream end of the exhaust expansion portion 17 to which the mounting stays 30 and 30 are fixed is enhanced in rigidity by the connection of the four exhaust pipes 16... And the mounting stays 30 and 30 themselves are bent by a curved sectional shape. Due to the rigidity, the mounting rigidity of the catalytic converter 26 by the mounting stays 30 can be sufficiently increased.
[0020]
Next, an embodiment of the present invention will be described with reference to FIGS.
[0021]
In the reference example described above, the catalytic converter 26 is supported on the exhaust expansion part 17 by the two mounting stays 30, 30. However, in this embodiment, the catalytic converter 26 is supported by the exhaust expansion part 17 by the single mounting stay 31. Is done. The mounting stay 31 is composed of a plate body having a corrugated cross section. Both ends of the mounting stay 31 are fixed to the inner wall surface of the exhaust expansion portion 17 by welding W ₈ , and the intermediate portion holds two catalytic converters 26. by fixing by welding W ₉ of the outer holder 28, the catalytic converter 26 is supported on the exhaust expansion unit 17.
[0022]
The inner wall surface of the intermediate part of the exhaust expansion part 17 has four concave semicircular concave surfaces arranged in the circumferential direction corresponding to the deformed cross section in which the four semicircles are arranged in the circumferential direction at the upstream end. has, both end portions of the attachment stay 31 is so formed along each of the two said concave having different inner wall surface of the intermediate portion of the exhaust expansion portion 17, respectively welded W ₈ into the two concave The
[0023]
According to this embodiment, since only one mounting stay 31 is required, not only the number of parts is reduced, but also the mounting stay 31 is arranged substantially parallel to the exhaust gas flow direction. Thus, the flow resistance of the exhaust gas can be further reduced.
[0024]
As mentioned above, although the reference example and the Example of this invention were explained in full detail, this invention can perform a various design change in the range which does not deviate from the summary.
[0025]
For example, in the embodiment, four exhaust pipes 16 are assembled in the exhaust expansion portion 17, but the number of exhaust pipes 16 to be assembled is not limited to four.
[0026]
【The invention's effect】
As described above, according to the first aspect of the present invention, the catalytic converter is disposed in the exhaust expansion portion where the passage cross-sectional area of the exhaust gas formed on the downstream side of the plurality of exhaust pipes increases. It is possible to minimize the increase in exhaust gas flow resistance. In addition, the catalytic converter is formed in a pipe shape that allows exhaust gas to pass inside and outside in the radial direction, and is arranged along the axis in the direction in which the exhaust gas flows, thereby enabling a smooth flow of the exhaust gas. Not only can the flow resistance be reduced more effectively, but also the exhaust gas can be effectively brought into contact with the catalytic converter to increase the purification efficiency. Further, the mounting stay is composed of a plate body formed in a waveform when viewed in a cross section orthogonal to the axis, and both ends of the mounting stay are on the inner wall surface of the exhaust expansion portion, and the intermediate portion of the mounting stay is Since each is fixed to the catalytic converter, not only the number of parts is reduced because only one mounting stay is required, but also the mounting stay is arranged substantially parallel to the exhaust gas flow direction. Further, the flow resistance of the exhaust gas can be further reduced.
[Brief description of the drawings]
1 is an overall side view of a motorcycle equipped with an exhaust gas purifying apparatus according to a reference example. FIG. 2 is an enlarged sectional view of part 2 in FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 2. FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. 4. FIG. 6 is a diagram corresponding to FIG. Sectional view of line 7 [Explanation of symbols]
16 Exhaust pipe 17 Exhaust expansion part 26 Catalytic converter 27 Inner holder 28 Outer holder 29 Steel wool 31 Mounting stay A Distance E Engine L Axis line

Claims

The downstream ends of the four exhaust pipes (16) extending from the multi-cylinder engine (E) are arranged adjacent to each other so that the axes of the downstream ends are located at the four corners of the square when viewed in a cross section orthogonal thereto. One exhaust expansion portion (17) for gathering the downstream ends is connected to the downstream ends of the four exhaust pipes (16) so that the passage cross-sectional area of the exhaust gas is increased at the gathering portions of the downstream ends. and setting, in the interior of the exhaust expansion portion (17), a catalytic converter (26) for purifying exhaust gas is disposed, the exhaust expansion portion (17) is reduced in outer diameter toward the downstream side from the upstream side From an upstream end connected to the four exhaust pipes (16) having a deformed cross section in which four semicircles are arranged at intervals of 90 ° in the circumferential direction. Toward the downstream end having a cross section and connected to one exhaust collecting pipe (18) The cross-sectional shape is smoothly changed, and the inner wall surface of the intermediate portion of the exhaust expansion portion (17) has four concave semicircular concave surfaces arranged in the circumferential direction corresponding to the deformed cross-section. An exhaust gas purification device comprising :
The catalytic converter (26) is formed in the shape of a pipe through which exhaust gas can pass inside and outside in the radial direction, and is arranged along the axis (L) in the direction in which the exhaust gas flows, and one mounting stay (31) ) To support the catalytic converter (26) on the exhaust expansion part (17),
The mounting stay (31) is constituted by a plate body having a waveform when viewed in a cross section perpendicular to the axis (L), and both ends of the mounting stay (31) are disposed on the exhaust expansion portion (17). of formed along each of the two said concave having different inner wall surface of the intermediate portion, respectively welded to the two concave with (W ₈₎ that, also the intermediate portion and the catalytic converter of the mounting stay (31) ( was fixed at 26),
The upstream end of the catalytic converter (26) reaches the vicinity of the downstream ends of the plurality of exhaust pipes (16), and the downstream end of the catalytic converter (26) is located a predetermined distance inside the exhaust collecting pipe (18). An exhaust gas purifying device characterized in that only (A) protrudes.

An outer peripheral surface of the catalytic converter (26) is fitted and slidably supported by two cylindrical inner holders (27), and radially outward of the inner holder (27). The two outer holders (28) formed in a semicircular cross section are fitted and fixed, and steel wool (29) is filled between the inner holder (27) and the outer holder (28). The intermediate portion of the mounting stay (31) is welded (W ₉ ) to the single outer holder (28), so that the catalytic converter (26) is fixed to the intermediate portion of the mounting stay (31). wherein the exhaust gas purification equipment according to claim 1.