JP7156902B2

JP7156902B2 - scarf

Info

Publication number: JP7156902B2
Application number: JP2018200346A
Authority: JP
Inventors: 雅之原
Original assignee: Marelli Corp
Current assignee: Marelli Corp
Priority date: 2018-10-24
Filing date: 2018-10-24
Publication date: 2022-10-19
Anticipated expiration: 2038-10-24
Also published as: JP2020067040A

Description

本発明は、自動車のエンジン等の内燃機関の排気系に設けられるマフラ（消音器）に関する。 The present invention relates to a muffler (silencer) provided in an exhaust system of an internal combustion engine such as an automobile engine.

例えば、自動車のエンジンに使用するマフラとして、特許文献１に開示されたものがある。この特許文献１に開示されたマフラは、２つの仕切壁により３つの室が形成されたマフラ本体と、このマフラ本体の第１室と第２室を貫通してガス圧が最も高くなる第３室に連通開口して該第３室に排気ガスを導入するインレットパイプと、第２室と第３室を貫通して第１室に連通開口して該第１室から外部へ排気ガスを導出するアウトレットパイプと、第２室を貫通して第１室と第３室に両端がそれぞれ開口し、第１室の開口端に該開口端を開閉するバルブを有するインナパイプ（排気パイプ）と、を備えている。 For example, Patent Document 1 discloses a muffler used in an automobile engine. The muffler disclosed in this Patent Document 1 includes a muffler body in which three chambers are formed by two partition walls, and a third chamber which penetrates the first and second chambers of the muffler body and has the highest gas pressure. an inlet pipe that communicates with the chamber and introduces the exhaust gas into the third chamber; and an inner pipe (exhaust pipe) passing through the second chamber and having both ends opened to the first and third chambers, respectively, and having a valve at the open end of the first chamber for opening and closing the open end; It has

そして、エンジンの低回転域の低流量時の排気ガスによって、バルブでインナパイプの開口端を閉じて消音性能を高め、エンジンの高回転域の大流量時の排気ガスによって、バルブでインナパイプの開口端を開いて排気抵抗の減少を図って背圧を低減するようになっている。 Exhaust gas at low engine speed at low flow rate closes the open end of the inner pipe with a valve to improve noise reduction performance. The open end is opened to reduce exhaust resistance and reduce back pressure.

特開平５－９８９３０号公報JP-A-5-98930

前記従来のマフラでは、バルブがマフラ本体内に設けられていて、エンジンの低回転域の低流量時にバルブが閉じて低周波域の気流音を消音できるようになっているが、中回転域ではバルブが開いて中周波域の気流音を消音することができなかった。 In the conventional muffler, the valve is provided in the muffler body, and the valve closes when the flow rate is low in the low speed range of the engine, so that the air flow noise in the low frequency range can be silenced. The valve could not be opened to muffle the mid-frequency airflow noise.

そこで、本発明は、前記した課題を解決すべくなされたものであり、低周波域から高周波域の広帯域の気流音を消音することができるマフラを提供することを目的とする。 SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a muffler capable of silencing airflow noise in a wide band from low to high frequencies.

本発明は、マフラ本体に複数のバッフルプレートにより仕切られる複数の消音室と拡張室を有したマフラにおいて、前記複数の消音室のうちの一つに挿入して排気ガスを導入して主流路となる排気ガス入口管を備え、前記排気ガス入口管の前記マフラ本体の外側部分に前記排気ガスの流れを制御する制御バルブが設けられ、前記制御バルブより排気ガスの上流側から分岐して前記排気ガスを前記排気ガス入口管が挿入される消音室とは異なる拡張室に導入するバイパス路としての排気ガスバイパス入口管が設けられ、前記排気ガスバイパス入口管より導入された排気ガスは、前記拡張室へ流れ、拡張消音効果を得た後、別の管路を通って、前記排気ガス入口管の主流路と合流して干渉した後、出口側の消音室に流出し、前記出口側の消音室内には、外部へ排気ガスを導出するテール管に連結されたアウトレット管の開口する端部が配置されていることを特徴とする。 The present invention provides a muffler having a muffler main body with a plurality of muffler chambers and an expansion chamber partitioned by a plurality of baffle plates, wherein the muffler body is inserted into one of the plurality of muffler chambers to introduce exhaust gas into the main flow path. A control valve for controlling the flow of the exhaust gas is provided in the outer portion of the muffler body of the exhaust gas inlet pipe, and the exhaust gas branches from the upstream side of the control valve to the exhaust gas. An exhaust gas bypass inlet pipe is provided as a bypass passage for introducing gas into an expansion chamber different from the muffling chamber into which the exhaust gas inlet pipe is inserted, and the exhaust gas introduced from the exhaust gas bypass inlet pipe is introduced into the expansion chamber. After it flows into the chamber and obtains an extended silencing effect, it passes through another conduit, merges with the main flow path of the exhaust gas inlet pipe and interferes with it, and then flows out into the silencing chamber on the outlet side, where the silencing effect on the outlet side is obtained. It is characterized in that an open end of an outlet pipe connected to a tail pipe for leading exhaust gas to the outside is arranged in the room.

本発明によれば、排気ガス入口管のマフラ本体の外側部分に排気ガスの流れを制御する制御バルブを設け、この制御バルブの開閉時にかかわらずマフラ本体内の消音回路を経由し、制御バルブの開時に長さの異なる排気ガス入口管による主流路と排気ガスバイパス入口管よるバイパス流路の集合部までで干渉回路を形成することにより、低周波域から高周波域の広帯域の気流音を効率良く消音することができる。 According to the present invention, a control valve for controlling the flow of exhaust gas is provided in the outer portion of the muffler body of the exhaust gas inlet pipe, and regardless of whether the control valve is open or closed, the control valve flows through the muffler circuit in the muffler body. By forming an interference circuit between the main flow path of the exhaust gas inlet pipes of different lengths and the bypass flow path of the exhaust gas bypass inlet pipe when the valve is open, a wide range of airflow noise from low to high frequencies can be effectively eliminated. Can be muted.

本発明の一実施形態のマフラを示す断面図である。1 is a cross-sectional view showing a muffler according to one embodiment of the present invention; FIG. 上記マフラの低流量時の排気ガスの流れを示す断面図である。FIG. 4 is a cross-sectional view showing the flow of exhaust gas when the flow rate of the muffler is low. 上記マフラの中流量時の排気ガスの流れを示す断面図である。FIG. 4 is a cross-sectional view showing the flow of exhaust gas in the muffler at a medium flow rate; 上記マフラの大流量時の排気ガスの流れを示す断面図である。FIG. 4 is a cross-sectional view showing the flow of exhaust gas when the muffler has a large flow rate; （ａ）～（ｃ）は上記マフラの各バルブ開度時の吸音レベルをそれぞれ比較して示すグラフである。(a) to (c) are graphs showing a comparison of the sound absorption level at each valve opening of the muffler.

以下、本発明の一実施形態を図面に基づいて説明する。 An embodiment of the present invention will be described below with reference to the drawings.

図１は本発明の一実施形態のマフラを示す断面図、図２はマフラの低流量時の排気ガスの流れを示す断面図、図３はマフラの中流量時の排気ガスの流れを示す断面図、図４はマフラの大流量時の排気ガスの流れを示す断面図、図５は（ａ）～（ｃ）はマフラの各バルブ開度時の排気ガスの吸音レベルをそれぞれ比較して示すグラフである。 FIG. 1 is a cross-sectional view showing a muffler according to one embodiment of the present invention, FIG. 2 is a cross-sectional view showing the flow of exhaust gas at low flow rate of the muffler, and FIG. 3 is a cross-sectional view showing the flow of exhaust gas at medium flow rate of the muffler. FIG. 4 is a cross-sectional view showing the flow of exhaust gas when the muffler has a large flow rate, and FIGS. graph.

図１に示すように、マフラ（消音器）１０のマフラシェル（マフラ本体）１１は、金属製で楕円筒状のアウタシェル１２と、このアウタシェル１２の両端開口部を閉塞する金属製で板状のアウタプレート１３ａ，１３ｂとで構成されており、図示しないエンジンから発生する気流音と高温の排気ガスＧを、金属製で板状の４つバッフルプレート（仕切壁）１４Ａ，１４Ｂ，１４Ｃ，１４Ｄで４つに区画された拡張室（消音室）１５と出口側の消音室１６と中間側の消音室１７と吸音室（消音室）１８及び消音室１９と、内部に設けられた低周波消音回路Ａと干渉回路Ｂ及び吸音回路（消音回路）Ｃとによって消音、冷却するものである。 As shown in FIG. 1, a muffler shell (muffler main body) 11 of a muffler (muffler) 10 includes an outer shell 12 made of metal and having an elliptical cylindrical shape, and outer plates made of metal closing openings at both ends of the outer shell 12. Four metal plate-like baffle plates (partition walls) 14A, 14B, 14C, and 14D block airflow noise and high-temperature exhaust gas G generated from an engine (not shown). An extension room (silencing room) 15, an exit-side silencer room 16, an intermediate-side silencer room 17, a sound-absorbing room (silencer room) 18, a silencer room 19, and a low-frequency silencer circuit A provided inside. , an interference circuit B, and a sound absorbing circuit (silencing circuit) C for muffling and cooling.

排気ガスＧをマフラシェル１１内に導入して主流路を構成する排気ガス入口管２０は、出口側の消音室１６に挿通され、Ｌ字形に曲がって中間側の消音室１７と吸音室１８を通過して入口側の消音室１９に端部２０ａを開口させている。 An exhaust gas inlet pipe 20, which introduces the exhaust gas G into the muffler shell 11 and constitutes the main flow path, is inserted through the muffler chamber 16 on the outlet side, bent in an L shape, and passes through the muffler chamber 17 and the sound absorbing chamber 18 on the intermediate side. Then, the end portion 20a is opened to the muffling chamber 19 on the entrance side.

また、排気ガス入口管２０のマフラシェル１１の外側部分には、排気ガスＧの流れを制御する制御バルブ２１が設けられている。この制御バルブ２１は、収納ケース２２内でモータの回転軸２１ａにより回転することで主流路である排気ガス入口管２０を開閉するようになっている。また、制御バルブ２１は、全閉と全開との間に中間開度を有している。この中間開度は、エンジンの中回転時（中回転域）での排気ガスの中流量時で制御バルブ２１がモータ制御により半分程度開くように設定されている。詳述すると、例えば、エンジンの回転数が２５００ｒｐｍ～５０００ｒｐｍの区間で、２０％～５０％の間で制御バルブ２１が開くように設定されている。 A control valve 21 for controlling the flow of the exhaust gas G is provided on the outside of the muffler shell 11 of the exhaust gas inlet pipe 20 . The control valve 21 is rotated by a rotating shaft 21a of a motor in the storage case 22 to open and close the exhaust gas inlet pipe 20, which is the main flow path. Also, the control valve 21 has an intermediate degree of opening between fully closed and fully opened. This intermediate degree of opening is set so that the control valve 21 is opened about half by motor control when the flow rate of the exhaust gas is medium at medium speed of the engine (in the middle speed range). More specifically, for example, the control valve 21 is set to open between 20% and 50% when the engine speed is between 2500 rpm and 5000 rpm.

さらに、排気ガス入口管２０の制御バルブ２１より排気ガスＧの上流側には、排気ガス入口管２０より細径のバイパス路を構成する排気ガスバイパス入口管２３が分岐している。この排気ガスバイパス入口管２３は、Ｌ字形に折り曲げ形成されており、排気ガスＧを排気ガス入口管２０が挿入される入口側の消音室１９とは異なる拡張室１５に導入する。即ち、排気ガスバイパス入口管２３の開口する端部２３ａは拡張室１５内に配置されている。 Further, upstream of the exhaust gas G from the control valve 21 of the exhaust gas inlet pipe 20, an exhaust gas bypass inlet pipe 23 forming a bypass passage having a diameter smaller than that of the exhaust gas inlet pipe 20 is branched. The exhaust gas bypass inlet pipe 23 is bent into an L shape, and introduces the exhaust gas G into the expansion chamber 15 different from the muffling chamber 19 on the entrance side into which the exhaust gas inlet pipe 20 is inserted. That is, the open end portion 23 a of the exhaust gas bypass inlet pipe 23 is arranged inside the expansion chamber 15 .

また、マフラシェル１１内には、拡張室１５内に開口する端部２４ａを有し、出口側の消音室１６を通過して、中間側の消音室１７でＬ字形に折り曲げられて他端部２４ｂを排気ガスバイパス入口管２３に連通させた別の管路としての貫通管２４と、入口側の消音室１９内に開口す端部２５ａを有し、吸音室（消音室）１８を通過して、中間側の消音室１７内に開口する他端部２５ｂを有した干渉管２５と、を備えている。 Further, the muffler shell 11 has an end portion 24a that opens into the expansion chamber 15, passes through the muffler chamber 16 on the outlet side, and is bent into an L shape in the muffler chamber 17 on the intermediate side to form the other end portion 24b. to the exhaust gas bypass inlet pipe 23 and an end portion 25a that opens into the silencer chamber 19 on the entrance side. , and an interference tube 25 having the other end 25b opening into the silencer chamber 17 on the intermediate side.

貫通管２４は、排気ガスバイパス入口管２３と同径の細径に形成されている。そして、排気ガスバイパス入口管２３より拡張室１５内に導入された排気ガスＧは、貫通管２４の開口する端部２４ａ内に流入され、中間側の消音室１７内を通過する部分の周壁２４ｃに形成された複数の貫通孔２４ｄより中間側の消音室１７中に流出し、残りの排気ガスＧは、排気ガス入口管２０より導入された排気ガスＧと合流した後に、入口側の消音室１９内に導入され、この入口側の消音室１９から干渉管２５を通って出口側の消音室１６に流出するようになっている。これにより、排気ガスバイパス入口管２３の開口する端部２３ａと貫通管２４の開口する端部２４ａが収納された拡張室１５内が低周波消音回路Ａとなっている。また、細径の排気ガスバイパス入口管２３と、太径の排気ガス入口管２０の細径の貫通管２４の他端部２４ｂからの合流部Ｐまでと、出口側の消音室１６から後述すると第２アウトレット管２７の他端部２７ｂと、に流れる排気ガスＧの流路が太径短経路の本流の干渉回路（干渉構造）Ｂとなっている。 The through pipe 24 is formed to have the same diameter as the exhaust gas bypass inlet pipe 23 . Exhaust gas G introduced into the expansion chamber 15 from the exhaust gas bypass inlet pipe 23 flows into the open end 24a of the through pipe 24, and passes through the silencer chamber 17 on the intermediate side. The remaining exhaust gas G flows out into the silencer chamber 17 on the middle side through a plurality of through holes 24d formed in , and the remaining exhaust gas G joins the exhaust gas G introduced from the exhaust gas inlet pipe 20, and then flows into the silencer chamber on the inlet side. 19, and flows out from the muffling chamber 19 on the inlet side to the muffling chamber 16 on the outlet side through the interference pipe 25. As shown in FIG. As a result, a low-frequency muffling circuit A is formed in the expansion chamber 15 in which the open end 23a of the exhaust gas bypass inlet pipe 23 and the open end 24a of the through pipe 24 are accommodated. In addition, from the small diameter exhaust gas bypass inlet pipe 23, the other end portion 24b of the small diameter penetration pipe 24 of the large diameter exhaust gas inlet pipe 20 to the confluence portion P, and the outlet side muffling chamber 16, as will be described later. The other end portion 27b of the second outlet pipe 27 and the flow path of the exhaust gas G flowing therethrough constitute a main flow interference circuit (interference structure) B with a large diameter short path.

また、排気ガスバイパス入口管２３より導入された排気ガスＧと排気ガス入口管２０より導入された排気ガスＧとが合流する下流側に位置する吸音室（消音室）１８に貫通された排気ガス入口管２０の部分の周壁２０ｃには複数の貫通孔２０ｄが設けられ、この複数の貫通孔２０ｄより吸音室１８に排気ガスＧの一部が流出するようになっている。さらに、干渉管２５の吸音室１８内に通過する部分の各周壁２５ｃに複数の貫通孔２５ｄを吸音室１８内で開口するように設けられている。この複数の貫通孔２５ｄは吸音材３０でそれぞれ覆われている。これらの貫通孔２０ｄ，２５ｄ及び貫通孔２５ｄを覆う吸音材３０が収納された吸音室１８内が排気ガスＧが集合後の吸音回路（吸音構造）Ｃとなっている。尚、干渉管２５の中間側の消音室１７内の周壁２５ｃにも複数の貫通孔２５ｄが設けられている。 In addition, the exhaust gas passes through a sound absorbing chamber (silencing chamber) 18 located downstream where the exhaust gas G introduced from the exhaust gas bypass inlet pipe 23 and the exhaust gas G introduced from the exhaust gas inlet pipe 20 join. A plurality of through holes 20d are provided in the peripheral wall 20c of the inlet pipe 20 portion, and part of the exhaust gas G flows into the sound absorbing chamber 18 through the plurality of through holes 20d. Furthermore, a plurality of through holes 25d are provided in each peripheral wall 25c of the interference tube 25 so as to open inside the sound absorbing chamber 18. As shown in FIG. The plurality of through holes 25d are each covered with a sound absorbing material 30. As shown in FIG. A sound absorbing circuit (sound absorbing structure) C after the exhaust gas G collects is formed in the sound absorbing chamber 18 containing the through holes 20d and 25d and the sound absorbing material 30 covering the through hole 25d. A plurality of through holes 25d are also provided in the peripheral wall 25c inside the silencer chamber 17 on the intermediate side of the interference tube 25. As shown in FIG.

さらに、マフラシェル１１内には、出口側の消音室１６内に開口する端部２６ａと、中間側の消音室１７と吸音室１８及び入口側の消音室１９を通過して外部に排気ガスＧを導出する他端部２６ｂと、を有する第１アウトレット管２６と、出口側の消音室１６内に開口する端部２７ａと、拡張室１５を通過して外部に排気ガスＧを導出する他端部２７ｂと、を有する第２アウトレット管２７と、第１アウトレット管２６の他端部２６ｂに連結され、外部に排気ガスＧを導出するＬ字形の第１デュアルテール管２８と、第２アウトレット管２７の他端部２７ｂに連結され、外部に排気ガスＧを導出するＬ字形の第２デュアルテール管２９と、を備えている。 Further, in the muffler shell 11, there are an end portion 26a that opens into the muffler chamber 16 on the exit side, the muffler chamber 17 and the sound absorbing chamber 18 on the middle side, and the muffler chamber 19 on the inlet side, and the exhaust gas G is supplied to the outside. the other end 26b leading out, the end 27a opening into the muffler chamber 16 on the outlet side, and the other end passing through the expansion chamber 15 to lead out the exhaust gas G to the outside. 27b, and an L-shaped first dual tail pipe 28 that is connected to the other end 26b of the first outlet pipe 26 and guides the exhaust gas G to the outside, and the second outlet pipe 27. and an L-shaped second dual tail pipe 29 connected to the other end 27b of the exhaust gas G to the outside.

尚、出口側の消音室１６と中間側の消音室１７を仕切るバッフルプレート１４Ｂ及び中間側の消音室１７と吸音室１８を仕切るバッフルプレート１４Ｃには、複数の貫通孔１４ｅ，１４ｆが設けられている。 A plurality of through-holes 14e and 14f are provided in a baffle plate 14B that separates the exit-side muffling chamber 16 and the middle-side muffling chamber 17, and a baffle plate 14C that separates the middle-side muffling chamber 17 and the sound-absorbing chamber 18. there is

以上実施形態のマフラ１０によれば、図２に示すように、エンジンの低回転域で、制御バルブ２１が全閉されて排気ガス入口管２０より分岐した排気ガスバイパス入口管２３のみからマフラシェル１１内に流入する排気ガスＧの低流量時には、排気ガスＧが、拡張室１５に開放され、拡張消音効果を得た後、貫通管２４を通って排気ガス入口管２０の合流部Ｐへ流れる。この前に、中間側の消音室１７内の貫通管２４の複数の貫通孔２４ｄで干渉され、吸音室１８内の排気ガス入口管２０の複数の貫通孔２０ｄ及び干渉管２５の複数の貫通孔２５ｄで吸音され、さらに、中間側の消音室１７内の干渉管２５の複数の貫通孔２５ｄで吸音されて、出口側の消音室１６に流出する。即ち、同一の中間側の消音室１７にそれぞれ貫通された貫通管２４の周壁２４ｃの複数の貫通孔２４ｄと、干渉管２５の周壁２５ｃの複数の貫通孔２５ｄと、の２経路で、異なる経路長の干渉を再度行う。これにより、低周波域から中周波域の気流音を消音する。尚、貫通管２４を通って排気ガス入口管２０の合流部Ｐへ流れた一部の排気ガスＧ′は、排気ガス入口管２０内を逆流して、ヘルムホルツのレゾネータとして機能する。 According to the muffler 10 of the above embodiment, as shown in FIG. 2, the control valve 21 is fully closed in the engine low speed range, and only the exhaust gas bypass inlet pipe 23 branched from the exhaust gas inlet pipe 20 is connected to the muffler shell 11. When the flow rate of the exhaust gas G flowing inside is low, the exhaust gas G is released into the expansion chamber 15, obtains an expansion silencing effect, and then flows through the penetration pipe 24 to the confluence portion P of the exhaust gas inlet pipe 20. Prior to this, the plurality of through holes 24d of the through pipe 24 in the middle silencer chamber 17 interfere with each other, and the plurality of through holes 20d of the exhaust gas inlet pipe 20 and the plurality of through holes of the interference pipe 25 in the sound absorbing chamber 18 25d, the sound is absorbed by a plurality of through-holes 25d of the interference tube 25 in the middle silencer chamber 17, and flows out to the exit silencer chamber 16. FIG. That is, the two paths, that is, the plurality of through holes 24d in the peripheral wall 24c of the through pipe 24 and the plurality of through holes 25d in the peripheral wall 25c of the interference tube 25, which penetrate the same middle silencer chamber 17, respectively, are different routes. Repeat long interference. As a result, the airflow noise in the low to medium frequency range is silenced. A part of the exhaust gas G' that has flowed through the through pipe 24 to the confluence P of the exhaust gas inlet pipe 20 flows backward in the exhaust gas inlet pipe 20 and functions as a Helmholtz resonator.

また、図３に示すように、エンジンの中回転域で、制御バルブ２１が半分程度開かれて排気ガス入口管２０及び排気ガスバイパス入口管２３からマフラシェル１１内に流入する排気ガスＧの中流量時には、排気ガスＧが排気ガスバイパス入口管２３と主流路が絞られた排気ガス入口管２０の長さ違いの経路を通って、貫通管２４と排気ガス入口管２０の合流部Ｐに到達する。この長さの異なるバイパス路と主流路の合流により、干渉回路Ｂが形成される。即ち、爆発次に高調波の波が半波長ずらし相殺され、低周波域から中周波域の気流音を消音できる。また、任意の運転条件（低・中・高速、低・中・高負荷）で、オーバー・オール（Ｏ．Ａ）を下げる低周波と高周波の適切なチューニングができる。さらに、制御バルブ２１の中間開時におけるエンジン上限回転数近傍の気流音は、貫通管２４と排気ガス入口管２０の合流部Ｐの合流後の吸音室１８内の排気ガス入口管２０の複数の貫通孔２０ｄ及び干渉管２５の複数の貫通孔２５ｄの吸音構造（吸音回路Ｃ）で吸音される。これにより、高周波域の気流音を消音できる。 Further, as shown in FIG. 3, in the middle rotation range of the engine, the control valve 21 is opened about halfway, and the flow rate of the exhaust gas G flowing into the muffler shell 11 from the exhaust gas inlet pipe 20 and the exhaust gas bypass inlet pipe 23 is moderate. Occasionally, the exhaust gas G passes through the exhaust gas bypass inlet pipe 23 and the exhaust gas inlet pipe 20 whose main flow path is narrowed and has different lengths, and reaches the junction P of the through pipe 24 and the exhaust gas inlet pipe 20. . An interference circuit B is formed by the confluence of the bypass channel and the main channel having different lengths. That is, the waves of higher harmonics after the explosion are shifted by half a wavelength and canceled, so that the airflow noise in the low to medium frequency range can be silenced. In addition, under any operating conditions (low/medium/high speed, low/medium/high load), low frequency and high frequency tuning can be appropriately performed to reduce the overall (OA). Furthermore, when the control valve 21 is intermediately opened, the airflow noise near the engine upper limit speed is generated by a plurality of exhaust gas inlet pipes 20 in the sound absorbing chamber 18 after the confluence P of the through pipe 24 and the exhaust gas inlet pipe 20. Sound is absorbed by the sound absorbing structure (sound absorbing circuit C) of the through hole 20 d and the plurality of through holes 25 d of the interference tube 25 . As a result, high-frequency airflow noise can be eliminated.

さらに、図４に示すように、エンジンの大回転域で、制御バルブ２１が全開されて排気ガス入口管２０及び排気ガスバイパス入口管２３からマフラシェル１１内に流入する排気ガスＧの大流量時には、前記の排気ガスＧの中流量時と同様に、排気ガスバイパス入口管２３と主流路が全開された排気ガス入口管２０の長さ違いの経路を通って、貫通管２４と排気ガス入口管２０の合流部Ｐに到達し、この合流部Ｐと中間側の消音室１７内の干渉管２５の複数の貫通孔２５ｄの干渉効果と流速低減で、中高周波に消音チューニングをシフトできる。また、制御バルブ２１の全開時におけるエンジン上限回転数近傍の気流音は、貫通管２４と排気ガス入口管２０の合流部Ｐの合流後の吸音室１８内の排気ガス入口管２０の複数の貫通孔２０ｄ及び干渉管２５の複数の貫通孔２５ｄの吸音構造（吸音回路Ｃ）で吸音される。これにより、高周波域の気流音を消音することができる。 Furthermore, as shown in FIG. 4, when the control valve 21 is fully opened and the exhaust gas G flowing into the muffler shell 11 from the exhaust gas inlet pipe 20 and the exhaust gas bypass inlet pipe 23 is large, the above-described In the same way as when the exhaust gas G has a medium flow rate, the through pipe 24 and the exhaust gas inlet pipe 20 pass through the exhaust gas bypass inlet pipe 23 and the exhaust gas inlet pipe 20 whose main flow path is fully opened. After reaching the junction P, the interference effect of the plurality of through holes 25d of the interference tube 25 in the silencer chamber 17 on the intermediate side and the flow velocity reduction can shift the muffling tuning to medium and high frequencies. Further, the airflow noise near the engine upper limit rotation speed when the control valve 21 is fully open is generated by a plurality of penetrations of the exhaust gas inlet pipe 20 in the sound absorbing chamber 18 after the confluence P of the through pipe 24 and the exhaust gas inlet pipe 20. Sound is absorbed by the sound absorbing structure (sound absorbing circuit C) of the holes 20 d and the plurality of through holes 25 d of the interference tube 25 . As a result, high-frequency airflow noise can be eliminated.

この制御バルブ２１が全閉、全開、中間開度における吸音レベルの実験例の結果を図５で示す。この実験例では、エンジンの回転途中で、中間開度を３０００ｒｐｍに設定してあり、図５（ａ）に示すように、高周波が支配的な高回転域のオーバー・オール（Ｏ．Ａ）が抑えられ、また、図５（ｂ），（ｃ）に示すように、爆発１次、爆発２次の低周波を下げるバランスの良い低減を選択することができる。 FIG. 5 shows the results of an experimental example of the sound absorption level when the control valve 21 is fully closed, fully opened, and intermediately opened. In this experimental example, the intermediate opening is set to 3000 rpm in the middle of engine rotation, and as shown in FIG. Also, as shown in FIGS. 5(b) and 5(c), it is possible to select a well-balanced reduction that lowers the low frequencies of the first order of the explosion and the second order of the explosion.

このように、排気ガス入口管２０のマフラシェル１１の外側部分に排気ガスＧの流れを制御する制御バルブ２１を設け、この制御バルブ２１の開閉時にかかわらずマフラシェル１１内の吸音回路（消音回路）Ｃを経由し、制御バルブ２１の開時に長さの異なる排気ガス入口管２０による主流路と排気ガスバイパス入口管２３よるバイパス流路の合流部（集合部）Ｐまでで干渉回路Ｂを形成することにより、低周波域から高周波域の広帯域の気流音を効率良く消音することができる。 In this manner, the control valve 21 for controlling the flow of the exhaust gas G is provided outside the muffler shell 11 of the exhaust gas inlet pipe 20, and the sound absorbing circuit (silencing circuit) C inside the muffler shell 11 is controlled regardless of whether the control valve 21 is open or closed. to form an interference circuit B up to a confluence portion (collection portion) P of the main flow path by the exhaust gas inlet pipe 20 and the bypass flow path by the exhaust gas bypass inlet pipe 23 when the control valve 21 is opened. As a result, it is possible to efficiently muffle wide-band airflow noise from low to high frequencies.

１０マフラ
１１マフラシェル（マフラ本体）
１４Ａ，１４Ｂ，１４Ｃ，１４Ｄバッフルプレート
１５拡張室
１６出口側の消音室
１７～１９消音室
２０排気ガス入口管（主流路）
２１制御バルブ
２３排気ガスバイパス入口管（バイパス路）
２４貫通管（別の管路）
２４ｄ貫通孔
２５干渉管
２５ｄ貫通孔
２６第１アウトレット管
２７第２アウトレット管
２８第１デュアルテール管（テール管）
２９第２デュアルテール管（テール管）
Ｇ排気ガス 10 muffler 11 muffler shell (muffler body)
14A, 14B, 14C, 14D Baffle plate 15 Expansion chamber 16 Silent chamber on exit side 17-19 Silent chamber 20 Exhaust gas inlet pipe (main passage)
21 control valve 23 exhaust gas bypass inlet pipe (bypass passage)
24 Penetration pipe (another conduit)
24d through hole 25 interference pipe 25d through hole 26 first outlet pipe 27 second outlet pipe 28 first dual tail pipe (tail pipe)
29 second dual tail pipe (tail pipe)
G Exhaust gas

Claims

In a muffler that has multiple muffling chambers and expansion chambers partitioned by multiple baffle plates in the muffler body,
an exhaust gas inlet pipe that is inserted into one of the plurality of muffling chambers to introduce exhaust gas and serve as a main flow path;
A control valve for controlling the flow of the exhaust gas is provided on the outer portion of the muffler body of the exhaust gas inlet pipe,
An exhaust gas bypass inlet pipe is provided as a bypass path for branching from the upstream side of the exhaust gas from the control valve and introducing the exhaust gas into an expansion chamber different from the silencer chamber into which the exhaust gas inlet pipe is inserted,
After the exhaust gas introduced from the exhaust gas bypass inlet pipe flows into the expansion chamber and obtains an expansion silencing effect, it passes through another pipe and merges with the main flow path of the exhaust gas inlet pipe to interfere. After that, it flows into the muffler room on the exit side,
A muffler, wherein an open end of an outlet pipe connected to a tail pipe for leading exhaust gas to the outside is disposed in the muffler chamber on the exit side.

The muffler according to claim 1,
provided in a portion of the pipe of the separate pipe that penetrates the silencer chamber located on the front side where the exhaust gas introduced from the exhaust gas bypass inlet pipe and the exhaust gas introduced from the exhaust gas inlet pipe join and a plurality of through holes provided in the tube portion of the interference tube penetrating through the same muffling chamber. scarf.

The muffler according to claim 1 or 2,
A muffler, wherein the electrically controlled valve has an intermediate degree of opening between fully closed and fully opened.