JP4268413B2

JP4268413B2 - Silencer for internal combustion engine

Info

Publication number: JP4268413B2
Application number: JP2003030192A
Authority: JP
Inventors: 幸弘中川
Original assignee: Nakagawa Sangyo Co Ltd
Current assignee: Nakagawa Sangyo Co Ltd
Priority date: 2003-02-07
Filing date: 2003-02-07
Publication date: 2009-05-27
Anticipated expiration: 2023-02-07
Also published as: JP2004239190A

Description

【０００１】
【発明の属する技術分野】
本発明は内燃機関の消音器に関する。
【０００２】
【従来の技術】
従来、内燃機関の排気系に配置される消音器においては、図７に示すように、排気管１０１に多数の小孔１０２を形成し、該小孔部の外周に、外筒１０３を設けて消音室１０４を形成し、排気管１０１内を流通する排気音を小孔１０２から消音室１０４内へ導入して減音するものが一般的である。
【０００３】
【発明が解決しようとする課題】
ところで、内燃機関より発生する排気ガスは、整流と乱流が混在したものであり、この排気ガスとともに流通する排気音を低減する手法として排気ガスを整流させることが考えられる。
【０００４】
前記従来の構造のように、排気管１０１に単に小孔１０２を形成したものにおいては、排気ガスが乱流状態で流通するため、前記のような排気ガスの整流による排気音の低減を図る上に問題があった。
【０００５】
そこで本発明は、前記のような、小孔と消音室を有する消音器において、前記の小孔を通じて流通する排気ガスの流れを整流化して、排気音の低減を図る内燃機関の消音器を提供することを目的とするものである。
【０００６】
【課題を解決するための手段】
前記の課題を解決するために、請求項１記載の発明は、排気管の外周に消音室を設け、該消音室における排気管に複数の小孔を形成した内燃機関の消音器において、
排気管に、該排気管の管軸に沿って一対の小孔を近接して形成するとともに該一対の小孔のうちの上流側の小孔部に、該小孔部の排気管を内側に曲げて排気管内を流通する排気ガスを小孔を通じて消音室内へ導出する導出壁を設け、下流側の小孔部に、該小孔部の排気管を内側に曲げて消音室内を流通する排気ガスを小孔を通じて排気管内の下流側へ導く導入壁を設けて、これらを内側整流部とし、
また、排気管に、該排気管の管軸に沿って一対の小孔を近接して形成するとともに該一対の小孔のうちの上流側の小孔部に、該小孔部の排気管を外側に曲げて消音室内を流通する排気ガスを小孔を通じて排気管内に導入する導入壁を設け、下流側の小孔部に、該小孔部の排気管を外側に曲げて排気管内を流通する排気ガスを小孔を通じて消音室の下流側へ導く導出壁を設けて、これらを外側整流部とし、
前記内側整流部と外側整流部を、排気管の管軸に沿って適宜間隔を有して交互に配設したことを特徴とするものである。
【０００７】
本発明においては内側整流部と外側整流部によって排気ガスが整流されて排気音の低減が図られる。
【００１０】
請求項２記載の発明は、前記請求項１の発明において、前記消音室内において、前記導出壁の外側であって排気管の全周にわたり、ステンレスウール層を設け、更に、該ステンレスウール層の外周に無機繊維層を設けたものである。
【００１１】
本発明においては、ステンレスウール層を設けることにより、前記導入壁の存在によって、排気管の外周面とステンレスウール層との間に空隙が生じ、この空隙を排気ガスが流通するため、排気ガスの整流を高めることができる。
【００１６】
【発明の実施の形態】
本発明の好ましい実施の形態を図１及び図６に基づいて説明する。
【００１７】
図１乃至図４は参考例を示す。
図１において、１は内燃機関より発生する排気ガスが流通する排気管で、排気ガスは、排気管１内を上流側Ａから下流側Ｂへ流通する。
【００１８】
前記排気管１には、複数の小孔２が形成されており、該小孔２を形成した部分の外周には外筒３によって消音室４が設けられている。
【００１９】
前記排気管１に形成した小孔２は、排気管１の管軸Ｘ−Ｘに沿って適宜間隔を有して複数形成されている。また、この小孔２は、排気管１の周方向にも複数個形成されており、周方向において隣接する小孔２は図３に示すように千鳥状に配置されている。
【００２０】
前記管軸Ｘ−Ｘに沿った１線上に形成された複数の小孔２の部分には、排気管１内を流通する排気ガスを小孔２を通じて消音室４内へ導出するための導出壁５と、消音室４内を流通する排気ガスを小孔２を通じて排気管１内へ導入する導入壁６が交互に設けられている。
【００２１】
前記小孔２と導出壁５は、排気管１の一部を排気管１の内側へ切り起こして小孔２を形成するとともに、この切り起こした片で導出壁５を形成している。更に、該導出壁５は、その下流側部５ａが排気管１に接続され、上流側部５ｂが排気管１の上流側Ａに指向するように切り起こされており、上流側に開口部５ｃを有し、両側に側壁５ｄを有する。また、前記下流側部５ａは曲面で形成されている。これにより、排気管１の内面部を流通する排気ガスは、図２の矢印Ｃで示すように、排気管１内に突出した導出壁５の開口部５ｃに導入され、その後、導出壁５に案内されて小孔２から消音室４内に導出される。
【００２２】
また、前記小孔２と導入壁６は、排気管１の一部を、排気管１の外側へ切り起こして小孔２を形成するとともに、この切り起こした片で導入壁６を形成している。更に、該導入壁６は、その下流側部６ａが排気管１に接続され、上流側部６ｂが、排気管１の上流側Ａに指向するように切り起こされており、上流側に開口部６ｃを有し、両側に側壁６ｄを有する。また、前記下流側部６ａは曲面で形成されている。これにより、排気管１の外面部を流通する排気ガスは、図２の矢印Ｄで示すように、排気管１外に突出した導入壁６の開口部６ｃに導入され、その後、導出壁６に案内されて小孔２から排気管１内に導入される。
【００２３】
前記消音室４内には、前記導出壁６の外側であって、排気管１の全周にわたって、図１及び図４に示すように、ステンレスウール層７が設けられ、更に該ステンレスウール層７の外周にガラス等の無機繊維層８を設けて吸音対策が施されている。
【００２４】
前記ステンレスウール層７は、前記導入壁６の存在により、導入壁６よりも外側に巻設されることになり、図４に示すように、ステンレスウール層７と排気管１との間に空隙９が形成される。また、該ステンレスウール層７の密度は、通常使用されている２００ｋｇ／ｍ³〜５００ｋｇ／ｍ³のステンレスウールを使用する。
【００２５】
以上のような構造であるから、図１に示す排気管１の上流側Ａから排気ガスが流入すると、その排気ガスの一部は、上流側の導出壁５の開口部５ｃに導入された後、導出壁５に案内されて小孔２から消音室４側へ導出され、その導出された排気ガスの一部が空隙９を流通して下流側へ流れ、その流れた排気ガスは、前記導出壁５の下流側に位置する導入壁６の開口部６ｃに導入された後、導入壁６に案内されて小孔２から排気管１内に導入される。そして、この導出壁６により排気管１内に導入された排気ガスは、その導入壁６より下流の導出壁５により小孔２から消音室４側へ導出され、これを繰り返して下流へ流れ、最後に排気管１の下流に配置された導入壁６に案内されて小孔２から排気管１内に入り、排気管１の下流へ排出される。
【００２６】
以上のような排気ガスの流れによって、排気管１内を流通する排気ガスの流れを整流化させることができ、排気音の低減を図ることができる。
【００２７】
図５及び図６は実施例１を示す。
【００２８】
図５において、１は前記と同様の排気管で、排気ガスは排気管１内を上流側Ａから下流側Ｂへ流通する。
【００２９】
前記排気管１には、排気管１の管軸Ｘ−Ｘに沿って１対の小孔２ａと小孔２ｂが、これらを近接させて形成され、その上流側の小孔２ａの部分には、排気管１内を流通する排気ガスを上流側の小孔２ａを通じて、前記と同様の消音室４内へ導出するための導出壁１０が設けられ、下流側の小孔２ｂの部分には、消音室４から下流側の小孔２ｂを通じて排気管１内側へ導入された排気ガスを、排気管１の下流側へ導く導入壁１１が設けられている。
【００３０】
前記上流側の小孔２ａと導出壁１０は、排気管１の一部を排気管１の内側へ切り起こして小孔２ａを形成するとともに、この切り起こした片で導出壁１０を形成している。更に、該導出壁１０は、その下流側部１０ａが排気管１に接続され、上流側部１０ｂが排気管１の上流側Ａに指向するように切り起こされており、上流側に開口部１０ｃを有し、両側に側壁１０ｄを有する。また、下流側部１０ａは曲面で形成されている。これにより、排気管１の内面部を流通する排気ガスは、図５の矢印Ｅで示すように、排気管１内に突出した導出壁１０の開口部１０ｃに導入され、導出壁１０に案内されて小孔２ａから消音室４内に導出される。
【００３１】
また、前記下流側の小孔２ｂと導入壁１１は、排気管１の一部を排気管１の内側へ切り起こして小孔２ｂを形成するとともに、この切り起こした片で導入壁１１を形成している。更に、該導入壁１１は、その上流側部１１ａが排気管１に接続され、下流側部１１ｂが排気管１の下流側Ｂに指向するように切り起こされており、下流側に開口部１１ｃを有し、両側に側壁１１ｄを有する。また、上流側部１１ａは曲面で形成されている。これにより、消音室４内を流通する排気ガスの一部は、図５の矢印Ｆで示すように、下流側の小孔２ｂに入った後、導入壁１１に案内されて排気管１内で下流へ導出される。
【００３２】
前記一対の小孔２ａ，２ｂの下流部、すなわち、前記排気管１の管軸に沿った下流部には、他の一対の小孔２ｃと小孔２ｄが、これらを近接させて形成されている。この他の一対の小孔２ｃ，２ｄのうちの上流側の小孔２ｃの部分には、消音室４内を流通する排気ガスを上流側の小孔２ｃを通じて排気管１内へ導入するための導入壁１２が設けられ、下流側の小孔２ｄの部分には、排気管１内から下流側の小孔２ｄを通じて消音室４内側へ導出された排気ガスを、消音室４の下流側へ導く導出壁１３が設けられている。
【００３３】
前記上流側の小孔２ｃと導入壁１２は、排気管１の一部を排気管１の外側へ切り起こして小孔２ｃを形成するとともに、この切り起こした片で導入壁１２を形成している。更に、該導入壁１２は、その下流側部１２ａが排気管１に接続され、上流側部１２が排気管１の上流側Ａに指向するように切り起こされており、上流側に開口部１２ｃを有し、両側に側壁１２ｄを有する。また、下流側部１２ａは曲面で形成されている。これにより、排気管１の外面部を流通する排気ガスは、図５の矢印Ｇで示すように、排気管１外に突出した導入壁１２の開口部１２ｃに導入され、導入壁１２に案内されて小孔２ｃから排気管１内に導入される。
【００３４】
また、前記下流側の小孔２ｄと導出壁１３は、排気管１の一部を排気管１の外側へ切り起こして小孔２ｄを形成するとともに、この切り起こした片で導出壁１３を形成している。更に、該導出壁１３は、その上流側部１３ａが排気管１に接続され、下流側部１３ｂが排気管１の下流側Ｂに指向するように切り起こされており、下流側に開口部１３ｃを有し、両側に側壁１３ｄを有する。また、上流側部１３ａは曲面で形成されている。これにより、排気管１内を流通する排気ガスの一部は、図５の矢印Ｈで示すように、下流側の小孔２ｄに入った後、導出壁１３に案内されて消音室４内で下流へ導出される。
【００３５】
前記一対の小孔２ａ，２ｂと導出壁１０と導入壁１１とからなる内側整流部Ｊと、前記一対の小孔２ｃ，２ｄと導入壁１２と導出壁１３とからなる外側整流部Ｋは、排気管１の管軸Ｘ−Ｘに沿った１線上において適宜間隔を有して交互に複数設けられている。また、前記内側整流部Ｊと外側整流部Ｋは、排気管の周方向にも複数個形成されており、周方向において隣接する内側整流部Ｊと外側整流部Ｋは図６に示すように千鳥状に配置されている。
【００３６】
また、本実施例１におけるその他の構造は前記参考例と同様である。
以上のような構造であるから、図５に示す排気管１の上流側Ａから排気ガスが流入すると、その排気ガスの一部は、内側整流部Ｊにおける上流側の導出壁１０の開口部１０ｃに導入された後、導出壁１０に案内されて小孔２ａから消音室４側へ導出され、その導出された排気ガスの一部が空隙９を流通して下流側へ流れ、その流れた排気ガスの一部は、前記導出壁１０の下流側に位置する小孔２ｂに入り、導入壁１１に案内されて排気管１内に導入される。そして、この導入壁１１により排気管１内に導入された排気ガスは下流へ流れる。
【００３７】
また、外側整流部Ｋにおける導入壁１２内に入った排気ガスは、小孔２ｃから排気管１内に入り、その一部は下流の小孔２ｄ内に入り、導出壁１３に案内されて消音室４の空隙９内を下流へ流れる。
【００３８】
これを繰り返して排気ガスは下流へ流れ、最後に排気管１の下流に配置された内側整流部Ｋに案内されて小孔２ｃから排気管１内に入り、排気管１の下流へ排出される。
【００３９】
本第２実施利においても、排気管１内を流通する排気ガスの流れを整流化させることができ、排気音の低減を図ることができる。
【００４０】
【発明の効果】
以上のようであるから本発明によれば、消音器内を流れる排気ガスを整流して排気音の低減を図ることができる。
【図面の簡単な説明】
【図１】本発明の参考例を示す消音器の側断面図。
【図２】図１における小孔と導出壁と導入壁を示す拡大側断面図。
【図３】本発明の参考例における小孔と導出壁と導入壁の配置状態を示す斜視図。
【図４】図１における要部の拡大側断面図。
【図５】本発明の実施例１における要部の拡大側断面図。
【図６】本発明の実施例１における小孔と導出壁と導入壁の配置状態を示す斜視図。
【図７】従来の消音器を示す側断面図。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a silencer for an internal combustion engine.
[0002]
[Prior art]
Conventionally, in a silencer disposed in an exhaust system of an internal combustion engine, as shown in FIG. 7, a large number of small holes 102 are formed in an exhaust pipe 101, and an outer cylinder 103 is provided on the outer periphery of the small hole portion. In general, a sound deadening chamber 104 is formed, and exhaust sound flowing through the exhaust pipe 101 is introduced into the sound deadening chamber 104 from the small hole 102 to reduce the sound.
[0003]
[Problems to be solved by the invention]
By the way, the exhaust gas generated from the internal combustion engine is a mixture of rectification and turbulent flow, and it is conceivable to rectify the exhaust gas as a technique for reducing the exhaust noise flowing with the exhaust gas.
[0004]
In the case where the small hole 102 is simply formed in the exhaust pipe 101 as in the conventional structure, the exhaust gas circulates in a turbulent state, so that exhaust noise can be reduced by rectifying the exhaust gas as described above. There was a problem.
[0005]
Therefore, the present invention provides a silencer for an internal combustion engine that reduces the exhaust noise by rectifying the flow of the exhaust gas flowing through the small hole in the silencer having the small hole and the silencer chamber as described above. It is intended to do.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the invention according to claim 1 is a silencer for an internal combustion engine in which a silencer chamber is provided on an outer periphery of an exhaust pipe, and a plurality of small holes are formed in the exhaust pipe in the silencer chamber.
A pair of small holes are formed close to the exhaust pipe along the tube axis of the exhaust pipe, and the exhaust pipe of the small hole portion is disposed inside the upstream small hole portion of the pair of small holes. Exhaust gas that circulates through the exhaust pipe by providing a lead-out wall that leads the exhaust gas that is bent and circulates through the small hole into the silencing chamber, and bends the exhaust pipe of the small hole inward at the small hole portion on the downstream Is provided with an introduction wall that leads to the downstream side in the exhaust pipe through a small hole, and these are used as the inner rectification unit,
Further, a pair of small holes are formed close to the exhaust pipe along the tube axis of the exhaust pipe, and the exhaust pipe of the small hole portion is provided in the small hole portion on the upstream side of the pair of small holes. An introduction wall that introduces exhaust gas that is bent outward and flows through the muffler chamber into the exhaust pipe through a small hole is provided, and the exhaust pipe of the small hole is bent outward and flows through the exhaust pipe in the small hole portion on the downstream side. Provide exhaust walls that guide exhaust gas through the small holes to the downstream side of the muffler chamber, and use these as outer rectifiers,
The inner rectifying unit and the outer rectifying unit are alternately arranged along the tube axis of the exhaust pipe with an appropriate interval .
[0007]
In the present invention, exhaust gas is rectified by the inner rectifier and the outer rectifier, and exhaust noise is reduced.
[0010]
According to a second aspect of the present invention, in the first aspect of the present invention, a stainless wool layer is provided outside the lead-out wall and over the entire circumference of the exhaust pipe in the silencer chamber, and the outer circumference of the stainless wool layer is further provided. Are provided with an inorganic fiber layer.
[0011]
In the present invention, by providing the stainless steel wool layer, a gap is formed between the outer peripheral surface of the exhaust pipe and the stainless wool layer due to the presence of the introduction wall, and the exhaust gas flows through the gap. Rectification can be increased.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of the present invention will be described with reference to FIGS.
[0017]
1 to 4 show a reference example.
In FIG. 1, reference numeral 1 denotes an exhaust pipe through which exhaust gas generated from the internal combustion engine flows. The exhaust gas flows from the upstream side A to the downstream side B in the exhaust pipe 1.
[0018]
A plurality of small holes 2 are formed in the exhaust pipe 1, and a sound deadening chamber 4 is provided by an outer cylinder 3 on the outer periphery of the portion where the small holes 2 are formed.
[0019]
A plurality of small holes 2 formed in the exhaust pipe 1 are formed at appropriate intervals along the tube axis XX of the exhaust pipe 1. A plurality of the small holes 2 are also formed in the circumferential direction of the exhaust pipe 1, and the small holes 2 adjacent in the circumferential direction are arranged in a staggered manner as shown in FIG.
[0020]
A plurality of small holes 2 formed on one line along the tube axis XX has a lead-out wall for leading the exhaust gas flowing through the exhaust pipe 1 into the silencer chamber 4 through the small holes 2. 5 and an introduction wall 6 for introducing exhaust gas flowing through the muffler chamber 4 into the exhaust pipe 1 through the small holes 2 are alternately provided.
[0021]
The small hole 2 and the lead-out wall 5 form a small hole 2 by cutting and raising a part of the exhaust pipe 1 to the inside of the exhaust pipe 1, and the lead-out wall 5 is formed by the cut and raised pieces. Further, the outlet wall 5 is cut and raised so that the downstream side portion 5a thereof is connected to the exhaust pipe 1 and the upstream side portion 5b is directed to the upstream side A of the exhaust pipe 1, and the opening portion 5c is provided upstream. And side walls 5d on both sides. The downstream side portion 5a is formed with a curved surface. As a result, the exhaust gas flowing through the inner surface of the exhaust pipe 1 is introduced into the opening 5c of the outlet wall 5 protruding into the exhaust pipe 1 as shown by an arrow C in FIG. It is guided and led out from the small hole 2 into the sound deadening chamber 4.
[0022]
Further, the small hole 2 and the introduction wall 6 are formed by cutting and raising a part of the exhaust pipe 1 to the outside of the exhaust pipe 1 to form the small hole 2 and forming the introduction wall 6 by the cut and raised pieces. Yes. Further, the introduction wall 6 is cut and raised so that the downstream side portion 6a thereof is connected to the exhaust pipe 1 and the upstream side portion 6b is directed to the upstream side A of the exhaust pipe 1, and an opening portion is provided upstream. 6c and side walls 6d on both sides. The downstream side portion 6a is formed with a curved surface. As a result, the exhaust gas flowing through the outer surface portion of the exhaust pipe 1 is introduced into the opening 6c of the introduction wall 6 protruding outside the exhaust pipe 1, as shown by an arrow D in FIG. It is guided and introduced into the exhaust pipe 1 from the small hole 2.
[0023]
As shown in FIGS. 1 and 4, a stainless wool layer 7 is provided in the silencer chamber 4 outside the outlet wall 6 and over the entire circumference of the exhaust pipe 1. An inorganic fiber layer 8 made of glass or the like is provided on the outer periphery of the substrate to take measures against sound absorption.
[0024]
The stainless wool layer 7 is wound outside the introduction wall 6 due to the presence of the introduction wall 6, and a gap is formed between the stainless wool layer 7 and the exhaust pipe 1 as shown in FIG. 4. 9 is formed. The density of the stainless wool layer 7 uses the stainless wool 200kg / m ^³ ~500kg / m ³ that is usually used.
[0025]
Because of the structure as described above, when exhaust gas flows from the upstream side A of the exhaust pipe 1 shown in FIG. 1, a part of the exhaust gas is introduced into the opening 5c of the outlet wall 5 on the upstream side. The exhaust gas is guided to the sound deadening chamber 4 side from the small hole 2 by being guided by the outlet wall 5, and a part of the exhaust gas thus circulated flows through the gap 9 to the downstream side. After being introduced into the opening 6 c of the introduction wall 6 located on the downstream side of the wall 5, it is guided by the introduction wall 6 and introduced into the exhaust pipe 1 from the small hole 2. Then, the exhaust gas introduced into the exhaust pipe 1 by the lead-out wall 6 is led out from the small hole 2 to the muffler chamber 4 side by the lead-out wall 5 downstream from the lead-in wall 6 and repeatedly flows downstream. Finally, the gas is guided by the introduction wall 6 disposed downstream of the exhaust pipe 1, enters the exhaust pipe 1 through the small hole 2, and is discharged downstream of the exhaust pipe 1.
[0026]
By the exhaust gas flow as described above, the flow of the exhaust gas flowing through the exhaust pipe 1 can be rectified, and the exhaust noise can be reduced.
[0027]
5 and 6 show the first embodiment .
[0028]
In FIG. 5, reference numeral 1 denotes an exhaust pipe similar to the above, and the exhaust gas flows from the upstream side A to the downstream side B in the exhaust pipe 1.
[0029]
A pair of small holes 2a and small holes 2b are formed in the exhaust pipe 1 along the tube axis XX of the exhaust pipe 1 so as to be close to each other. A exhaust wall 10 is provided to guide exhaust gas flowing through the exhaust pipe 1 through the small hole 2a on the upstream side into the muffler chamber 4 similar to the above, and a portion of the small hole 2b on the downstream side includes An introduction wall 11 is provided for guiding the exhaust gas introduced into the exhaust pipe 1 from the silencer chamber 4 through the small hole 2b on the downstream side to the downstream side of the exhaust pipe 1.
[0030]
The upstream small hole 2a and the outlet wall 10 are formed by cutting and raising a part of the exhaust pipe 1 to the inside of the exhaust pipe 1 to form the small hole 2a, and forming the outlet wall 10 with the cut and raised pieces. Yes. Further, the outlet wall 10 is cut and raised so that the downstream side portion 10a thereof is connected to the exhaust pipe 1 and the upstream side portion 10b is directed to the upstream side A of the exhaust pipe 1, and the opening portion 10c is formed upstream. And side walls 10d on both sides. Moreover, the downstream side part 10a is formed in the curved surface. As a result, the exhaust gas flowing through the inner surface of the exhaust pipe 1 is introduced into the opening 10c of the outlet wall 10 protruding into the exhaust pipe 1 and guided to the outlet wall 10 as indicated by an arrow E in FIG. The small hole 2a is led into the sound deadening chamber 4.
[0031]
Further, the small hole 2b and the introduction wall 11 on the downstream side cut and raise a part of the exhaust pipe 1 to the inside of the exhaust pipe 1 to form the small hole 2b, and the introduction wall 11 is formed by this cut and raised piece. is doing. Further, the introduction wall 11 is cut and raised so that the upstream side portion 11a is connected to the exhaust pipe 1 and the downstream side portion 11b is directed to the downstream side B of the exhaust pipe 1, and the opening portion 11c is formed on the downstream side. And side walls 11d on both sides. Further, the upstream side portion 11a is formed with a curved surface. As a result, as shown by the arrow F in FIG. 5, a part of the exhaust gas flowing through the muffler chamber 4 enters the downstream small hole 2b and is then guided by the introduction wall 11 in the exhaust pipe 1. Derived downstream.
[0032]
In the downstream part of the pair of small holes 2a, 2b, that is, the downstream part along the tube axis of the exhaust pipe 1, another pair of small holes 2c and small holes 2d are formed close to each other. Yes. In the portion of the upstream small hole 2c of the other pair of small holes 2c, 2d, exhaust gas flowing through the silencer chamber 4 is introduced into the exhaust pipe 1 through the upstream small hole 2c. An introduction wall 12 is provided, and the exhaust gas led out from the exhaust pipe 1 to the inside of the silencer chamber 4 through the downstream small hole 2d is guided to the downstream side of the silencer chamber 4 in the downstream small hole 2d portion. A lead-out wall 13 is provided.
[0033]
The upstream small hole 2c and the introduction wall 12 are formed by cutting and raising a part of the exhaust pipe 1 to the outside of the exhaust pipe 1 to form the small hole 2c, and forming the introduction wall 12 with the cut and raised pieces. Yes. Further, the introduction wall 12 is cut and raised so that the downstream side portion 12a thereof is connected to the exhaust pipe 1, the upstream side portion 12 is directed to the upstream side A of the exhaust pipe 1, and the opening portion 12c is formed upstream. And side walls 12d on both sides. Moreover, the downstream side part 12a is formed in the curved surface. As a result, the exhaust gas flowing through the outer surface of the exhaust pipe 1 is introduced into the opening 12c of the introduction wall 12 protruding outside the exhaust pipe 1 and guided to the introduction wall 12, as indicated by an arrow G in FIG. Are introduced into the exhaust pipe 1 through the small holes 2c.
[0034]
Further, the downstream small hole 2d and the lead-out wall 13 cut and raise a part of the exhaust pipe 1 to the outside of the exhaust pipe 1 to form the small hole 2d, and the lead-out wall 13 is formed by this cut and raised piece. is doing. Further, the outlet wall 13 is cut and raised so that the upstream side portion 13a is connected to the exhaust pipe 1 and the downstream side portion 13b is directed to the downstream side B of the exhaust pipe 1, and the opening portion 13c is formed on the downstream side. And side walls 13d on both sides. The upstream side portion 13a is formed with a curved surface. As a result, a part of the exhaust gas flowing through the exhaust pipe 1 enters the downstream small hole 2d as shown by the arrow H in FIG. Derived downstream.
[0035]
The inner rectification portion J composed of the pair of small holes 2a, 2b, the lead-out wall 10 and the introduction wall 11, and the outer rectification portion K composed of the pair of small holes 2c, 2d, the introduction wall 12 and the lead-out wall 13, A plurality of the exhaust pipes 1 are alternately provided at appropriate intervals on one line along the tube axis XX of the exhaust pipe 1. Further, a plurality of inner rectifying sections J and outer rectifying sections K are also formed in the circumferential direction of the exhaust pipe, and the inner rectifying sections J and outer rectifying sections K adjacent in the circumferential direction are staggered as shown in FIG. Arranged in a shape.
[0036]
The other structures in the first embodiment are the same as those in the reference example .
Since the structure is as described above, when the exhaust gas flows in from the upstream side A of the exhaust pipe 1 shown in FIG. 5, a part of the exhaust gas is part of the opening 10 c of the upstream outlet wall 10 in the inner rectifying part J. Then, the exhaust gas is guided by the outlet wall 10 and led out from the small hole 2a to the silencer chamber 4 side, and a part of the led exhaust gas flows through the gap 9 to the downstream side, and the exhaust gas that has flowed therethrough. A part of the gas enters the small hole 2 b located on the downstream side of the outlet wall 10, is guided by the introduction wall 11, and is introduced into the exhaust pipe 1. The exhaust gas introduced into the exhaust pipe 1 by the introduction wall 11 flows downstream.
[0037]
Further, the exhaust gas that has entered the introduction wall 12 in the outer rectifying section K enters the exhaust pipe 1 through the small hole 2c, and part of it enters the downstream small hole 2d and is guided by the outlet wall 13 to mute. It flows downstream in the gap 9 in the chamber 4.
[0038]
By repeating this, the exhaust gas flows downstream. Finally, the exhaust gas is guided by the inner rectifying section K disposed downstream of the exhaust pipe 1, enters the exhaust pipe 1 through the small hole 2 c, and is discharged downstream of the exhaust pipe 1. .
[0039]
Also in the second embodiment, the flow of the exhaust gas flowing through the exhaust pipe 1 can be rectified, and the exhaust noise can be reduced.
[0040]
【The invention's effect】
As described above, according to the present invention, exhaust gas flowing in the silencer can be rectified to reduce exhaust noise.
[Brief description of the drawings]
FIG. 1 is a side sectional view of a silencer showing a reference example of the present invention.
FIG. 2 is an enlarged side sectional view showing a small hole, a lead-out wall, and an introduction wall in FIG.
FIG. 3 is a perspective view showing an arrangement state of small holes, lead-out walls, and introduction walls in a reference example of the present invention.
4 is an enlarged side cross-sectional view of the main part in FIG.
FIG. 5 is an enlarged side cross-sectional view of a main part in Embodiment 1 of the present invention.
FIG. 6 is a perspective view showing an arrangement state of small holes, lead-out walls, and introduction walls in Embodiment 1 of the present invention.
FIG. 7 is a side sectional view showing a conventional silencer.

Claims

In the silencer of the internal combustion engine in which a silencer chamber is provided on the outer periphery of the exhaust pipe, and a plurality of small holes are formed in the exhaust pipe in the silencer chamber.
A pair of small holes are formed close to the exhaust pipe along the tube axis of the exhaust pipe, and the exhaust pipe of the small hole portion is disposed inside the upstream small hole portion of the pair of small holes. Exhaust gas that circulates through the exhaust pipe by providing a lead-out wall that leads the exhaust gas that is bent and circulates through the small hole into the silencing chamber through the small hole Through the small hole to the downstream side in the exhaust pipe, these are the inner rectification part,
Further, a pair of small holes are formed close to the exhaust pipe along the tube axis of the exhaust pipe, and the exhaust pipe of the small hole portion is provided in the small hole portion on the upstream side of the pair of small holes. An introduction wall that introduces exhaust gas that is bent outward and flows through the muffler chamber into the exhaust pipe through a small hole is provided, and the exhaust pipe of the small hole is bent outward and flows through the exhaust pipe in the small hole portion on the downstream side. Provide outlet walls that guide exhaust gas to the downstream side of the sound deadening chamber through a small hole, and these are the outer rectifiers,
A muffler for an internal combustion engine, wherein the inner rectifying unit and the outer rectifying unit are alternately arranged with an appropriate interval along the tube axis of the exhaust pipe.

In the muffling chamber, over the entire circumference of the exhaust pipe a outside of the outer rectifying unit, a stainless steel wool layer provided, further, the internal combustion engine according to claim 1, wherein the inorganic fiber layer is provided on the outer periphery of the stainless wool layer Silencer.