JPH0658131A - Silencer for internal combustion engine - Google Patents

Abstract

PURPOSE:To reduce exhaust noise extending over a wide frequency region effectively by making an opening rate of influence bypass holes opened in the pipe of a silencer for an internal combustion engine larger toward downstream side so as to allow uniform interfering action. CONSTITUTION:An inlet pipe 6, inner pipes 7, 8, and an outlet pipe 9 are provided in a resonance chamber 10 and enlarging chambers 11, 12, and exhaust gas is discharged through arrows B, C, the enlarging chamber 12, and the outlet pipe 9 in order. Bypass holes 14 in the inlet pipe 6 are provided at equal spaces in a range A, and in this case, the holes 14 having a diameter becoming larger toward a downstream side is formed. The amount of exhaust gas discharged from the bypass holes 14 becomes uniform extending over a wide distribution range and interference action is carried out in main gas flow uniformly extending over a wide frequency range. Thus, the exhaust noise is reduced extending over a wide frequency region.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は内燃機関用消音器に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silencer for an internal combustion engine.

【０００２】[0002]

【従来の技術】図４に従来の消音器の代表例を示す。１
はアウタシェル、２，３はアウタプレート、４，５はイ
ンナプレート、６はインレットパイプ、７，８はインナ
パイプ、９はアウトレットパイプ、１０は共鳴室、１１
と１２は拡張室である。2. Description of the Related Art FIG. 4 shows a typical example of a conventional silencer. 1
Is an outer shell, 2 and 3 are outer plates, 4 and 5 are inner plates, 6 is an inlet pipe, 7 and 8 are inner pipes, 9 is an outlet pipe, 10 is a resonance chamber, 11
And 12 are expansion chambers.

【０００３】インレットパイプ６に流入した排気ガス
は、共鳴室Ｂ内を矢印Ｂのように通過し、インナパイプ
７を通って拡張室１１に流入し、矢印Ｃに示すように主
ガス流となって拡張室１１内を通過し、インナパイプ８
を通って拡張室１２へ入り、更にアウトレットパイプ９
を通って排出される。The exhaust gas flowing into the inlet pipe 6 passes through the resonance chamber B as shown by an arrow B, passes through the inner pipe 7 into the expansion chamber 11 and becomes a main gas flow as shown by an arrow C. Pass through the inside of the expansion chamber 11 and reach the inner pipe 8
Through the expansion chamber 12 and the outlet pipe 9
Is discharged through.

【０００４】インレットパイプ６には符号Ａで示す範囲
にわたって多数のバイパス穴１３が明けてあり、このバ
イパス穴から吐出する排気ガスが、矢印Ｂ、Ｃのように
廻り込んで来た主ガス流と干渉して、経路差で定まる周
波数の排気音を低減する。A large number of bypass holes 13 are formed in the inlet pipe 6 over the range indicated by the symbol A, and the exhaust gas discharged from the bypass holes is the same as the main gas flow coming in as shown by arrows B and C. Interference reduces exhaust noise at a frequency determined by the path difference.

【０００５】[0005]

【発明が解決しようとする課題】前記従来の技術では、
インレットパイプ内を右方に流れる排ガスの圧力は、下
流（図示右方）になる程低くなる。又、共鳴室１０を矢
印Ｂのようにう回して拡張室１１内を矢印Ｃのように流
れる主ガス流の圧力は、拡張室１１内の右から左にいく
程低くなる。SUMMARY OF THE INVENTION In the above conventional technique,
The pressure of the exhaust gas flowing to the right in the inlet pipe becomes lower toward the downstream (to the right in the drawing). Further, the pressure of the main gas flow flowing around the resonance chamber 10 as indicated by the arrow B and flowing through the inside of the extension chamber 11 as indicated by the arrow C becomes lower as it goes from right to left inside the extension chamber 11.

【０００６】従って、同じ大きさのバイパス穴１３から
吐出する排ガスの吐出量は、上流のバイパス穴程多く、
下流のバイパス穴程少なくなる。各バイパス穴から拡張
室１１内へ吐出する吐出量を図４に上向きの矢印で示す
が、上流のバイパス穴１３で吐出量が最も大きいため、
矢印が最も長く、下流にいく程吐出量が少ないので矢印
の長さが短かくしてある。Therefore, the discharge amount of the exhaust gas discharged from the bypass holes 13 of the same size is larger in the upstream bypass holes,
Fewer bypass holes downstream. The discharge amount discharged from each bypass hole into the expansion chamber 11 is shown by an upward arrow in FIG. 4, but since the discharge amount is the largest in the upstream bypass hole 13,
The length of the arrow is short because the arrow is the longest and the amount of discharge is smaller toward the downstream side.

【０００７】このように、バイパス穴１３からの排ガス
の吐出量が、下流のバイパス穴程小さくなり、Ａの範囲
にわたり均一でないため、干渉作用により有効に消音で
きる周波数範囲が限られてくるという問題点があった。As described above, since the discharge amount of the exhaust gas from the bypass hole 13 becomes smaller in the downstream bypass hole and is not uniform over the range A, there is a problem that the frequency range in which the noise can be effectively silenced due to the interference effect is limited. There was a point.

【０００８】そこで、本発明は、このような問題点を解
消できる消音器を提供することを目的とする。[0008] Therefore, an object of the present invention is to provide a silencer capable of solving such a problem.

【０００９】[0009]

【課題を解決するための手段】前記目的を達成するため
に、本発明の内燃機関用消音器は、パイプ（６）に明け
た干渉用バイパス穴（１４，１４ａ，１４ｂ，１４ｃ）
の開口率を下流にいく程大きく定めたことを特徴とす
る。In order to achieve the above object, the silencer for an internal combustion engine according to the present invention has an interference bypass hole (14, 14a, 14b, 14c) formed in a pipe (6).
It is characterized in that the aperture ratio of is set to be larger toward the downstream side.

【００１０】[0010]

【作用】パイプの内と外の圧力差は、下流のバイパス穴
程小さいが、下流程バイパス穴の開口率が大きいため、
バイパス吐出量はバイパス穴の分布範囲にわたり、上流
から下流までほぼ均一になる。[Function] The pressure difference between the inside and the outside of the pipe is smaller in the downstream bypass hole, but the opening ratio of the bypass hole is larger in the downstream side.
The bypass discharge amount is almost uniform from upstream to downstream over the distribution range of the bypass holes.

【００１１】その結果、前記経路差で定まる周波数範囲
にわたり、干渉作用が有効かつ均一に行なわれる。As a result, the interference action is effectively and uniformly performed over the frequency range defined by the path difference.

【００１２】[0012]

【実施例】図１の実施例で、１４はインレットパイプ６
に明けたバイパス穴で、符号Ａで示す範囲にわたり等間
隔に設けられ、下流（図示右方）の穴程大きな直径のバ
イパス穴としてある。Embodiment In the embodiment of FIG. 1, 14 is an inlet pipe 6.
The bypass holes are provided at equal intervals over the range indicated by the symbol A, and the downstream (right side in the drawing) holes have larger diameters.

【００１３】こうすることで、Ａの範囲内で、下流にい
く程バイパス穴の開口率が大きくなっている。なお、図
１の実施例のように、下流にいく程バイパス穴１４の径
を大きくする代りに、同じ径のバイパス穴の間隔（ピッ
チ）を下流にいく程小さくすることで、下流にいく程開
口率を大きくしてもよい。By doing so, the opening ratio of the bypass hole becomes larger in the range of A toward the downstream side. As in the embodiment of FIG. 1, instead of increasing the diameter of the bypass holes 14 in the downstream direction, the distance (pitch) between the bypass holes of the same diameter is decreased in the downstream direction, and The aperture ratio may be increased.

【００１４】又、バイパス穴の径を下流程大きく、バイ
パス穴の間隔（ピッチ）を下流程小さくしてもよい。図
２の実施例では、インレットパイプ６に明けたバイパス
穴を２群に分け、上流の群を小さい径のバイパス穴１４
ａで、下流の群を大きい径のバイパス穴１４ｂで構成す
ることで、下流程開口率を大きくした。Further, the diameter of the bypass holes may be increased downstream and the interval (pitch) between the bypass holes may be decreased downstream. In the embodiment shown in FIG. 2, the bypass hole formed in the inlet pipe 6 is divided into two groups, and the upstream group has a small diameter bypass hole 14
In a, the aperture ratio is increased toward the downstream side by configuring the downstream group with the bypass hole 14b having a large diameter.

【００１５】図３の実施例は、上記図１、図２の実施例
に比較して、インナプレート５Ａと、インナーパイプ７
Ａ及び拡張室１１Ａが多く、又、インレットパイプ６に
設けたバイパス穴が３つの群れに分かれている。The embodiment shown in FIG. 3 is different from the embodiments shown in FIGS. 1 and 2 in the inner plate 5A and the inner pipe 7.
There are many A and expansion chambers 11A, and the bypass holes provided in the inlet pipe 6 are divided into three groups.

【００１６】すなわち、バイパス穴１４ａ，１４ｂ，１
４ｃからなる３群が、下流程大きな径のバイパス穴で構
成されているため、下流程その開口率が大きい。なお、
図１〜図３の実施例で符号１〜１２で示す従来技術と同
じ符号の部分は、図４の従来技術と同じ作用をするので
説明を省略する。That is, the bypass holes 14a, 14b, 1
Since the third group consisting of 4c is composed of bypass holes having a larger diameter in the downstream side, the aperture ratio is larger in the downstream side. In addition,
In the embodiments of FIGS. 1 to 3, the parts having the same reference numerals as those of the conventional art shown by reference numerals 1 to 12 have the same operations as those of the conventional art of FIG.

【００１７】[0017]

【発明の効果】本発明の内燃機関用消音器は前述のよう
に構成されているので、バイパス穴からの吐出量が、そ
の分布範囲にわたって均一になる。従って、回り込んで
来た主ガス流と、広い周波数範囲にわたって有効かつ均
一に干渉作用を行なうことができるため、広い周波数帯
域にわたり効果的な排気音の低減ができる。Since the silencer for an internal combustion engine of the present invention is constructed as described above, the discharge amount from the bypass hole becomes uniform over the distribution range. Therefore, it is possible to effectively and uniformly interfere with the circulated main gas flow over a wide frequency range, so that exhaust noise can be effectively reduced over a wide frequency band.

【図面の簡単な説明】[Brief description of drawings]

【図１】 本発明の実施例の縦断面略図。FIG. 1 is a schematic vertical sectional view of an embodiment of the present invention.

【図２】 本発明の他の実施例の縦断面略図。FIG. 2 is a schematic vertical sectional view of another embodiment of the present invention.

【図３】 本発明の更に他の実施例の縦断面図。FIG. 3 is a vertical sectional view of still another embodiment of the present invention.

【図４】 従来技術の縦断面略図。FIG. 4 is a schematic vertical sectional view of the prior art.

【符号の説明】[Explanation of symbols]

６ インレットパイプ １４，１４ａ，１４ｂ，１４ｃ バイパス穴 6 Inlet pipe 14, 14a, 14b, 14c Bypass hole

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 パイプに明けた干渉用バイパス穴の開口
率を下流にいく程大きく定めたことを特徴とする内燃機
関用消音器。1. A silencer for an internal combustion engine, wherein an opening ratio of an interference bypass hole formed in a pipe is set to be larger toward a downstream side.