JPH01208516A - Exhaust device of multi-cylinder engine - Google Patents

Abstract

PURPOSE:To raise torque in an overall speed range, by providing main exhaust passages from respective exhaust ports of cylinders to collecting parts and subsidiary exhaust passages branched off from main exhaust passage, and providing opening-closing valves in the subsidiary exhaust passages on the position of nearly equal distance from the branch-off point to the collecting parts. CONSTITUTION:Exhaust passages 9, 12 of No.1, No.4 cylinders 1, 4 and exhaust passages 10, 11 of No.2, No.3 cylinders 2, 3 in which exhaust strokes are not sequential, are respectively collected to No.1, No.2 collecting parts 13, 14. Each of the collecting parts 13, 14 is collected to a total cylinder collecting part 19 through each of main exhaust pipes 17, 18 and silencers 20, 21 are connected on its downstream side for damping pulsation in low and medium frequency region. Two subsidiary exhaust passages 22, 23 are branched off immediately after the collecting parts 13, 14 in respective main exhaust pipes 17, 18, and respective subsidiary exhaust passages 22, 23 are collected to a sub-manifold collecting part 24, and this collecting part 24 is communicated to an exhaust pipe 25 on the downstream side of the silencer 20 through a connecting pipe 26. And an opening-closing valve 27 is provided in each of the subsidiary exhaust passages 22, 23 and controlled to be closed below medium and low speed range.

Description

【発明の詳細な説明】 （産業上の利用分野） この発明は、例えば、排気系の残留ガス割合を低減して
出力の向上を図るような多気筒エンジンの排気装置に関
する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an exhaust system for a multi-cylinder engine, which aims to improve output by reducing the proportion of residual gas in the exhaust system, for example.

（従来技術） 従来、多気筒エンジンの排気装置としては、例えば、第
５図に示す如き構造の排気装置がある。(Prior Art) Conventionally, as an exhaust system for a multi-cylinder engine, there is an exhaust system having a structure as shown in FIG. 5, for example.

すなわち、第１気筒６１、第２気筒６２、第３気ｆｉ１
６３、第４気筒６４のそれぞれの排気ポート６５．６６
．６７．６８に排気通路６９，７０゜７１．７２を接続
し、上述の各気筒６１．６２゜６３．６４の点火順序を
第１気筒６１、第３気筒６３、第４気筒６４、第２気筒
６２の順に設定すると共に、排気行程が連続しない第１
気筒６１の排気通路６９と第４気筒６４の排気通路７２
とを集合させて第１集合部７３を形成し、同様に排気行
程が連続しない第２気筒６２の排気通路７０と第３気筒
６３の排気通路７１とを集合させて第２集合部７４を形
成し、さらに、上述の第１および第２の各集合部７３．
７４に連通させた各排気管７５．７６を、その下流側に
おいて集合させて全気筒集合部７７を形成すると共に、
この全気筒集合部７７の下流にサイレンサ７８．７９を
連通させた多気筒エンジンの排気装置である。That is, the first cylinder 61, the second cylinder 62, the third cylinder fi1
63, each exhaust port 65 and 66 of the fourth cylinder 64
．． Connect exhaust passages 69, 70° 71.72 to 67.68, and change the firing order of each cylinder 61.62° 63.64 to 1st cylinder 61, 3rd cylinder 63, 4th cylinder 64, 2nd cylinder. 62, and the first exhaust stroke is not continuous.
Exhaust passage 69 of cylinder 61 and exhaust passage 72 of fourth cylinder 64
are gathered together to form a first gathering part 73, and similarly, the exhaust passage 70 of the second cylinder 62 and the exhaust passage 71 of the third cylinder 63, whose exhaust strokes are not continuous, are brought together to form a second gathering part 74. Furthermore, each of the above-mentioned first and second gathering parts 73.
The exhaust pipes 75 and 76 communicated with the exhaust pipe 74 are collected on the downstream side thereof to form an all-cylinder collection part 77, and
This is an exhaust system for a multi-cylinder engine in which silencers 78 and 79 are communicated downstream of this all-cylinder gathering portion 77.

第５図に示す従来の排気装置の出力特性図は第６図の点
線Ｓの如くなる。The output characteristic diagram of the conventional exhaust system shown in FIG. 5 is as shown by the dotted line S in FIG.

すなわち、第６図において吸気系のみの特性を実線ｔで
示すと、最大出力回転側と付近において排気系の動的効
果が得られるように設定するため、エンジン高速域では
ブローダウンによる排気ガスの圧力波が前述の全気筒集
合部７７で負圧波となって逆流伝播され、この負圧波が
エキゾーストクローズＥＣ直前の気筒に作用するので、
排気弁部の圧力波形Ｕにおいて斜線を施して示すように
、この負圧エネルギで排気ガスを吹出を掃気効果（第６
図の斜線部■参照）が得られ、実線ｔの特性から点線Ｓ
のようにエンジントルクが向上する。In other words, if the characteristics of only the intake system are shown by the solid line t in Fig. 6, the settings are made so that the dynamic effect of the exhaust system is obtained at and near the maximum output speed, so in the engine high speed range, the exhaust gas due to blowdown is reduced. The pressure wave turns into a negative pressure wave in the all-cylinder collecting section 77 and is propagated backwards, and this negative pressure wave acts on the cylinder immediately before the exhaust close EC.
As shown by diagonal lines in the pressure waveform U of the exhaust valve section, this negative pressure energy causes the exhaust gas to be blown out due to the scavenging effect (6th
) is obtained, and from the characteristics of the solid line t, the dotted line S
As a result, engine torque is improved.

なお、ｐｅｘは平均背圧を示す。Note that pex indicates average back pressure.

一方、エンジン中速域では、高速域に比較してエンジン
回転数が低下する関係上、エキゾーストオープンＥＯか
らエキゾーストクローズＥＣまでの期間が長くなり、圧
力波の気筒、全気筒集合部７７間の往復回数が増えて、
エキゾーストクローズＥＣ直前に、排気弁部の圧力波形
Ｗにおいて斜Ｉ！ｉｌ×を施して示すように気筒内に正
圧波が作用して、逆効果（第６図の斜線ｙ参照）となり
、実線ｔの特性から点線Ｓで示すようにエンジントルク
が低下する欠点があった。On the other hand, in the engine medium speed range, since the engine speed is lower than in the high speed range, the period from exhaust open EO to exhaust close EC becomes longer, and the pressure wave moves back and forth between the cylinders and the all cylinder gathering part 77. The number of times has increased,
Immediately before the exhaust closes EC, the pressure waveform W at the exhaust valve section shows an oblique I! As shown by applying il×, a positive pressure wave acts inside the cylinder, resulting in the opposite effect (see the diagonal line y in Fig. 6), which has the disadvantage that the engine torque decreases as shown by the dotted line S from the characteristic shown by the solid line t. Ta.

このような欠点を解決するために、従来、例えば、実開
昭６１−１５２７１７号公報に記載のようなエンジンの
排気管装置がある。In order to solve these drawbacks, there has conventionally been an engine exhaust pipe device as described in, for example, Japanese Utility Model Application Publication No. 152717/1983.

１なわち、２つの排気出口をそれぞれ有する複数の排気
マニホルドと、同各排気マニホルドからの排気ガスを集
合させて下流側へ導く排気管とを有するエンジンの排気
管装置において、上述の排気管を、各排気マニホルドの
出口から集合部までの長さが短い第１流路と、各排気マ
ニホルドの出口から集合部までの長さが長い第２流路と
、同第１、第２２１！路の集合部から下流側へ延びる集
合流路とにより構成すると共に、エンジン低回転時には
上述の第１流路の排気流れを遮断し、エンジン高回転時
には上述の第２流路の排気流れを遮断することで、エン
ジントルクの向上を図った排気管装置である。1. That is, in an engine exhaust pipe device having a plurality of exhaust manifolds each having two exhaust outlets and an exhaust pipe that collects exhaust gas from each exhaust manifold and guides it to the downstream side, the above-mentioned exhaust pipe is used. , a first passage having a short length from the outlet of each exhaust manifold to the collecting part, and a second passage having a long length from the outlet of each exhaust manifold to the collecting part; It is composed of a collecting flow path extending downstream from the collecting part of the passages, and blocks the exhaust flow in the above-mentioned first flow path when the engine speed is low, and blocks the exhaust flow in the above-mentioned second flow path when the engine speed is high. This is an exhaust pipe device designed to improve engine torque.

しかし、この装置においては、排気系の長さが長くなる
問題点を有していた。However, this device had a problem in that the length of the exhaust system was long.

（発明の目的） この発明は、集合部までの距離を短く設定しながら全回
転域のトルクの向上を図ることができる多気筒エンジン
の排気装置の提供を目的とする。(Object of the Invention) An object of the present invention is to provide an exhaust system for a multi-cylinder engine that can improve torque in the entire rotation range while setting the distance to the gathering part short.

〈発明の構成） この発明は、シリンダ内に開口する排気ポート開口部か
ら全気筒の排気通路集合部までの主排気通路と、上記主
排気通路からそれぞれ分岐した副排気通路とを設けると
共に、上記副排気通路には、該通路の分岐部から上記集
合部までの距離と略等長の位置に開閉弁を設け、上記開
閉弁をエンジンの中速回転域以下で閉弁制ｍａする制御
手段を備えた多気筒エンジンの排気装置であることを特
徴とする。(Structure of the Invention) The present invention provides a main exhaust passage from an exhaust port opening opened in a cylinder to an exhaust passage gathering part of all cylinders, and sub-exhaust passages branched from the main exhaust passage, and also provides the above-mentioned The auxiliary exhaust passage is provided with an on-off valve at a position approximately equal in length to the distance from the branching part of the passage to the gathering part, and a control means for controlling the on-off valve to close below a medium speed rotation range of the engine. It is characterized by being an exhaust system for a multi-cylinder engine.

（発明の効果） この発明によれば、エンジンの中速回転域以下で、［述
の制御手段が、副排気通路の所定位置に設けた上述の開
閉弁を閉弁操作するので、排気ブローダウンにより主排
気通路と副排気通路とに分流した排気ガスは、主排気通
路の集合部において逆位相の負圧波（膨張波）となって
気筒側に逆流するが、副排気通路の閉弁操作された開閉
弁位置で同位相の正圧波（圧縮波）となって同時刻に逆
流するので、この正圧波が上述の負圧波を相殺する。(Effects of the Invention) According to the present invention, the above-mentioned control means closes the above-mentioned on-off valve provided at a predetermined position of the auxiliary exhaust passage at or below the medium speed rotation range of the engine. The exhaust gas that is divided into the main exhaust passage and the sub-exhaust passage becomes a negative pressure wave (expansion wave) with an opposite phase at the convergence part of the main exhaust passage and flows back to the cylinder side, but when the sub-exhaust passage is closed. At the opening/closing valve position, a positive pressure wave (compression wave) of the same phase occurs and flows backward at the same time, so this positive pressure wave cancels the above-mentioned negative pressure wave.

この結束、エキゾーストクローズ直前に気筒内に作用す
る正圧波が大幅に減衰するので、エンジンの中速回転域
以下においてトルクの向上を図ることができる効果があ
る。This bundling greatly attenuates the positive pressure waves that act within the cylinder just before the exhaust closes, so it has the effect of improving torque in the engine's mid-speed rotation range and below.

また、エンジン高速回転域では上述の制御手段が開閉弁
を開弁操作するので、排気系の容量が増大し、背圧が低
下するので、残留ガス割合が減少して、出力が向上する
と共に、排気ガスは主排気通路と副排気通路との両通路
に分散して流出されるため、騒音が低下し、また集合部
の温度低下を図ることもできる。In addition, in the engine high speed range, the above-mentioned control means opens the on-off valve, so the capacity of the exhaust system increases and the back pressure decreases, so the residual gas ratio decreases and the output improves. Since the exhaust gas is dispersed and discharged into both the main exhaust passage and the auxiliary exhaust passage, noise is reduced and the temperature of the collecting portion can also be lowered.

しかも、上述の開閉弁の配設位置は、分岐部から集合部
までの距離と略等長の位置に設定しているので、排気系
の距離を短（しながら上述の効果、つまり全回転域のト
ルクの向上を図ることができる。Moreover, since the above-mentioned opening/closing valve is installed at a position that is approximately the same length as the distance from the branching part to the gathering part, the distance of the exhaust system can be shortened (while achieving the above-mentioned effect, that is, the entire rotation range). The torque can be improved.

（実施例） この発明の一実施例を以下図面に基づいて詳述する。(Example) An embodiment of the present invention will be described in detail below based on the drawings.

図面は多気筒エンジンの排気装置を示し、第１図におい
て、第１気筒１、第２気筒２、第３気筒３および第４気
ｌ１１４のそれぞれの排気ポート５゜６．７．８に排気
通路９．１０．１１．１２を接続し、上述の各気筒１〜
４の点火順序を第１気筒１、第３気筒３、第４気筒４、
第２気筒２の順に設定している。The drawing shows an exhaust system for a multi-cylinder engine, and in FIG. 1, an exhaust passage is provided at each exhaust port 5°6. 9. Connect 10.11.12 and connect each cylinder 1 to above.
The ignition order for 4 cylinders is 1st cylinder 1, 3rd cylinder 3, 4th cylinder 4,
They are set in the order of the second cylinder 2.

そして、排気行程が連続しない第１気筒１の排気通路９
と第４気筒４の排気通路１２とを集合させて第１集合部
１３を形成し、同様に排気行程が連続しない第２気筒２
の排気通路１０と第３気筒３の排気通路１１とを集合さ
せて第２集合８１１１４を形成して、上述の合計４本の
排気通路９〜１２を２つの排気通路群１５．１６に区分
している。Then, the exhaust passage 9 of the first cylinder 1 whose exhaust stroke is not continuous
and the exhaust passage 12 of the fourth cylinder 4 are assembled to form a first gathering part 13, and similarly the exhaust stroke of the second cylinder 2 is not continuous.
The exhaust passage 10 of the third cylinder 3 and the exhaust passage 11 of the third cylinder 3 are assembled to form a second set 81114, and the above-mentioned total four exhaust passages 9 to 12 are divided into two exhaust passage groups 15 and 16. ing.

また、上述の第１および第２の各集合部１３゜１４に連
通させた主排気管１７．１８を、その下流側において集
合させて仝気ｖ：Ｉ集合部１９を形成すると共に、この
全気筒集合部１９には低中周波域減衰用のサイレンサ２
０とサイレンサ２１とを連通させている。Further, the main exhaust pipes 17 and 18 that communicate with the first and second collecting parts 13 and 14 described above are collected on the downstream side thereof to form an air v:I collecting part 19, and this entire A silencer 2 for attenuating the low and medium frequency range is installed in the cylinder collection section 19.
0 and the silencer 21 are communicated with each other.

さらに、上述の主排気管１７．１８における集合部１３
．１４直後から２木の副排気通路２２゜２３を分岐形成
し、これら２本の副排気通路２２゜２３を副マニホルド
集合部２４で集合させると共に、この副マニホルド集合
部２４と、サイレンサ２０下流側の排気管２５との間を
連通管２６で連通させている。Furthermore, the collecting portion 13 in the main exhaust pipe 17.18 mentioned above
．． Immediately after 14, two sub-exhaust passages 22, 23 are branched, and these two sub-exhaust passages 22, 23 are collected at the sub-manifold gathering part 24, and this sub-manifold gathering part 24 and the silencer 20 downstream side. A communication pipe 26 communicates between the exhaust pipe 25 and the exhaust pipe 25 .

しかも、上述の副マニホルド集合部２４の直前における
上述の各副排気通路２２．２３には、それぞれ開閉弁２
７．２７を設けている。In addition, each of the above-mentioned sub-exhaust passages 22 and 23 immediately before the above-mentioned sub-manifold collection section 24 has an on-off valve 2, respectively.
7.27 has been established.

そして、上述の副排気通路２２．２３の分岐部２８から
前述の全気筒集合部１９までの距離ｇ１と、分岐部２８
からｙ’ａｍ弁２７介設位置までの距Ｍｆ１２とを略等
長ｊ　Ｉ　Ｊ−ｊ　２に設定している。Then, the distance g1 from the branch part 28 of the above-mentioned auxiliary exhaust passage 22.23 to the above-mentioned all-cylinder gathering part 19, and the branch part 28
The distance Mf12 from the position where the y'am valve 27 is provided is set to be approximately the same length j I J-j 2.

上述の２つのｒＭｒ１１弁２７．２７は同一の弁軸２９
により開閉され、この弁軸２９の外端には第１図に示す
如く、リンク３０を介してアクチュエータ３１の操作ロ
ッド３２を連結し、この操作ロッド３２をダイヤフラム
３３に固定すると共に、上述のアクチュエータ３１のス
プリング室３４を、三方ソレノイド３５および逆止弁３
６を介して、例えば、吸気負圧作用部位としての吸気マ
ニホルドのスロットル弁後位に接続している。The two rMr11 valves 27, 27 mentioned above have the same valve stem 29
As shown in FIG. 1, an operating rod 32 of an actuator 31 is connected to the outer end of the valve shaft 29 via a link 30, and the operating rod 32 is fixed to a diaphragm 33. 31 spring chamber 34, three-way solenoid 35 and check valve 3
6, it is connected, for example, to a position downstream of the throttle valve of the intake manifold, which serves as an intake negative pressure acting site.

上述の三方ソレノイド弁３５のソレノイド３７はＣＰｔ
Ｊ４０により駆動制御される。The solenoid 37 of the three-way solenoid valve 35 mentioned above is CPt.
The drive is controlled by J40.

すなわち、上述のＣＰｔＪ４０はエンジン回転数信号の
入力に基づいて、ＲＯＭ３８に格納したプログラムに従
って上述の三方ソレノイド弁３５のソレノイド３７を駆
動制御し、またＲＡＭ３９は前述の開閉弁２７．２７の
開閉コントロール領域データ等の必要なデータを記憶す
る。That is, the above-mentioned CPtJ40 drives and controls the solenoid 37 of the above-mentioned three-way solenoid valve 35 according to the program stored in the ROM 38 based on the input of the engine rotation speed signal, and the RAM 39 controls the opening/closing control area of the above-mentioned on-off valve 27.27. Store necessary data such as data.

ここで、上述のＣＰＵ４０は三方ソレノイド３５および
アクチュエータ３１を介して開閉弁２７゜２７をエンジ
ンの中速回転域以下で開弁制御し、エンジン高速回転域
およびエンジン低速回転域で開弁制御する制御手段であ
る。Here, the above-mentioned CPU 40 controls the on-off valves 27 and 27 to open below the engine's medium speed rotation range through the three-way solenoid 35 and the actuator 31, and controls the valves to open in the engine high speed rotation range and the engine low speed rotation range. It is a means.

図示実施例は上記の如く構成するものにして、以下作用
を説明する。The illustrated embodiment is constructed as described above, and its operation will be explained below.

ＣＰＵ４０に入力されるエンジン回転数信号に基づいて
、ＣＰＵ４０はエンジン回転数を検出し、現行のエンジ
ン回転数がｎ回転であると判定した際には、ＣＰＵ４０
は三方ソレノイド弁３５のソレノイド３７を非励磁制御
して、開閉弁２７，２７を第２図に開閉特性ａで示す如
く開弁状態に制御する。Based on the engine rotation speed signal input to the CPU 40, the CPU 40 detects the engine rotation speed, and when determining that the current engine rotation speed is n rotations, the CPU 40 detects the engine rotation speed.
The solenoid 37 of the three-way solenoid valve 35 is de-energized to control the on-off valves 27, 27 to be in the open state as shown by the on-off characteristic a in FIG.

このため、エンジン高速域ではブローダウンによる排気
ガスの圧力波が前述の全気筒集合部１９で負圧波となっ
て逆流伝播され、この負圧波がエキゾーストクローズＥ
Ｃ直前の気筒に作用するので、排気弁部の圧力波形は第
２図に特性すで示す如くなり、この特性すの斜線部に相
当する負圧エネルギにより排気ガスを吹出寸撞気効果が
得られる。Therefore, in the engine high-speed range, the exhaust gas pressure wave due to blowdown becomes a negative pressure wave at the all-cylinder collecting section 19 and propagates backward, and this negative pressure wave is transmitted to the exhaust close E.
Since it acts on the cylinder immediately before C, the pressure waveform of the exhaust valve part has characteristics as shown in Fig. 2, and the negative pressure energy corresponding to the shaded part of this characteristic has the effect of blowing out the exhaust gas. It will be done.

しかも、前述の開閉弁２７．２７の開放により排気系の
容量が増大し、背圧が低下するので、残留ガス割合は従
来の特性２から特性Ｃに減少し、エンジントルクは従来
の点線Ｓで示す特性ｄのように向上すると共に、排気ガ
スが主排気管１７゜１８と副排気通路２２．２３との両
道路に分散して流出するため、騒音が低下し、また全気
筒集合部１９の温度低下を図ることもできる。Furthermore, the capacity of the exhaust system increases and the back pressure decreases due to the opening of the above-mentioned on-off valve 27.27, so the residual gas ratio decreases from the conventional characteristic 2 to characteristic C, and the engine torque changes from the conventional dotted line S. In addition to improving the characteristic d shown in Fig. 3, the exhaust gas is dispersed and flows out to both the main exhaust pipe 17, 18 and the auxiliary exhaust passage 22, 23, so the noise is reduced, and the all-cylinder collecting section 19 is improved. It is also possible to lower the temperature.

一方、現行のエンジン回転数が中速領域であるとＣＰＵ
４０が判定した場合には、このＣＰＵ４０は三方ソレノ
イド弁３１のソレノイド３７を励磁制御する。On the other hand, if the current engine speed is in the medium speed range, the CPU
40, the CPU 40 controls the excitation of the solenoid 37 of the three-way solenoid valve 31.

上述のソレノイド３７が励磁されると、アクチュエータ
３１のスプリング室３４に、例えば、吸気負圧が導入さ
れるのでダイレフラム３３を介して操作ロッド３２が閉
弁方向に操作され、リンク３０を介して上述の各開閉弁
２７．２７が閉弁される。When the above-mentioned solenoid 37 is energized, for example, intake negative pressure is introduced into the spring chamber 34 of the actuator 31, so the operating rod 32 is operated in the valve closing direction via the dial flamm 33, and the above-mentioned operation is performed via the link 30. Each on-off valve 27.27 is closed.

このため、エンジン中速域では、排気ブローダウンによ
り主排気管１７．１８とａｊ排気通路２２゜２３とに分
流した排気ガスは、主排気管１７．１８下流の全気筒集
合部１９において逆位相の負圧波（膨張波）となって気
筒側に逆流するが、副排気通路２２．２３の閉弁操作さ
れた開閉弁２７゜２７位置で同位相の正圧波（圧縮波）
となって同時刻に逆流するので、この正圧波が上述の負
圧波を相殺する。Therefore, in the engine medium speed range, the exhaust gas that is divided into the main exhaust pipe 17.18 and the aj exhaust passage 22° 23 due to exhaust blowdown has an opposite phase at the all-cylinder gathering part 19 downstream of the main exhaust pipe 17.18. It becomes a negative pressure wave (expansion wave) and flows back to the cylinder side, but a positive pressure wave (compression wave) of the same phase occurs at the 27° 27 position of the closed valve in the auxiliary exhaust passage 22, 23.
Since the current flows backward at the same time, this positive pressure wave cancels out the above-mentioned negative pressure wave.

この結果、排気弁部の圧力特性は第２図、第３図に実線
で示す剛性波ｅとなり、エキゾーストクローズＥＣ直前
に気筒内に作用する正圧波が大幅に減衰（第３図の特性
ｆ参照）し、エンジン中速回転域において第２図に特性
ｄで示す如くエンジントルクの向上を図ることができる
効果がある。As a result, the pressure characteristic of the exhaust valve section becomes a rigid wave e shown by the solid line in Figs. 2 and 3, and the positive pressure wave acting in the cylinder immediately before exhaust close EC is significantly attenuated (see characteristic f in Fig. 3). ), and there is an effect that the engine torque can be improved as shown by characteristic d in FIG. 2 in the engine medium speed rotation range.

しかも、上述の開閉弁２７．２７の配設位置は、高回転
設定の排気系において前述の分岐部２８から全気筒集合
部１９までの距［１と略等長（Ｊ）１＆ｄ２＞の位置に
設定しているので、排気系の距離を短かくしながら全回
転域のトルクの向上を図ることができる効果がある。Furthermore, the above-mentioned on-off valves 27 and 27 are arranged at a position at a distance [approximately equal length (J)1 &d2> from the above-mentioned branching part 28 to the all-cylinder gathering part 19 in an exhaust system set at high rotation speed. This setting has the effect of shortening the distance of the exhaust system while improving torque across the entire rotation range.

第４図は排気装置の他の実施例を示し、全気筒１〜４の
それぞれの排気ポート５〜８に接続した主マニホルド４
１．４２．４３．４４を全気筒集合部１９で集合させる
と共に、上述の主マニホルド４１〜４４から分岐するそ
れぞれの副マニホルド４５・・・を設けて、これら各副
マニホルド４５・・・を副マニホルド集合部２４で集合
させ、この副マニホルド集合部２４直前における各副マ
ニホルド４５・・・にエンジン中速回転域で閉弁する開
開弁２７・・・を設け、分岐部２８から全気筒集合部１
９までの距離ρ３と、分岐部２８から開閉弁２７介設位
置までの距離１４とを略等長Ｊ３＋ρ４に設定している
。FIG. 4 shows another embodiment of the exhaust system, in which a main manifold 4 is connected to exhaust ports 5 to 8 of all cylinders 1 to 4, respectively.
1,42, 43, and 44 are collected in the all-cylinder collecting part 19, and each sub-manifold 45 branching from the above-mentioned main manifolds 41 to 44 is provided, and each of these sub-manifolds 45... is used as a sub-manifold. All the cylinders are collected at the manifold collecting part 24, and each sub manifold 45 immediately before the sub manifold collecting part 24 is provided with an on-off valve 27 that closes in the engine medium speed rotation range, and all cylinders are collected from the branch part 28. Part 1
The distance ρ3 to 9 and the distance 14 from the branch portion 28 to the intervening position of the on-off valve 27 are set to approximately equal lengths J3+ρ4.

このように構成しても、先の実施例と略同様の作用効果
を奏するので、第４図において第１図と同一の部分には
同一番号を付してその詳しい説明を省略する。Even with this configuration, substantially the same effects as in the previous embodiment can be achieved, so in FIG. 4, the same parts as in FIG. 1 are given the same numbers, and detailed explanation thereof will be omitted.

この発明の構成と、上述の実施例との対応において、 この発明のシリンダは、実施例の各気筒１〜４に対応し
、 以下同様に、 全気筒の排気通路集合部は、全気筒集合部１９に対応し
、 主排気通路は、第１実施例の排気通路群１５゜１６、主
排気管１７．１８および第２実施例の主マニホルド４１
〜４４に対応し、 副排気通路は、第１実施例の副排気通路２２゜２３およ
び第２実施例の副マニホルド４５に対応し、 制御手段は、ＣＰＵ４０に対応するも、この発明は上述
の実施例の構成のみに限定されるものではなく、 例えば、上記構成を６気筒エンジンに適用してもよいこ
とは勿論である。In the correspondence between the structure of this invention and the above-described embodiment, the cylinder of this invention corresponds to each cylinder 1 to 4 of the embodiment, and similarly, the exhaust passage gathering portion of all cylinders is the all cylinder gathering portion. 19, the main exhaust passage includes the exhaust passage group 15.16 of the first embodiment, the main exhaust pipe 17.18, and the main manifold 41 of the second embodiment.
-44, the sub-exhaust passage corresponds to the sub-exhaust passages 22 and 23 of the first embodiment and the sub-manifold 45 of the second embodiment, and the control means corresponds to the CPU 40; It goes without saying that the present invention is not limited to the configuration of the embodiment, and that the above configuration may be applied to a six-cylinder engine, for example.

【図面の簡単な説明】[Brief explanation of the drawing]

図面はこの発明の一実施例を示し、 第１図は多気筒エンジンの排気装置を示す系統図、第２
図はエンジン回転数に対するエンジントルク、残留ガス
割合、開閉弁開度のそれぞれの特性を示す特性図、 第３図はエンジン中速域における排気弁部の圧力特性図
、 第４図は多気筒エンジンの排気装置の他の実施例を示す
系統図、 第５図は従来の多気筒エンジンの排気装置を示す系統図
、 第６図は従来の排気系の出力特性図である。 １・・・第１気筒　　　　　２・・・第２気筒３・・・
第３気筒　　　　　４・・・第４気筒５〜８・・・排気
ポート　１５．１６・・・排気通路群１７．１８・・・
主排気管　１９・・・全気筒集合部２２．２３・・・副
排気通路　　２７・・・開閉弁２８・・・分岐部　　　
　　４０・・・ＣＰＵ４１〜４４・・・主マニホルド ４５・・・副マニホルド 、シー・ 代理人　弁理士　永　１）良　昭　１″）鷺　　　　、
−／ ′・、１７ １・・・第１気問 冴 々 区 へ 法 Ｃ】 派The drawings show one embodiment of the present invention, and FIG. 1 is a system diagram showing an exhaust system for a multi-cylinder engine, and FIG.
The figure is a characteristic diagram showing the characteristics of engine torque, residual gas ratio, and opening/closing valve opening with respect to engine speed. Figure 3 is a pressure characteristic diagram of the exhaust valve section in the engine medium speed range. Figure 4 is a multi-cylinder engine FIG. 5 is a system diagram showing another embodiment of the exhaust system for a conventional multi-cylinder engine. FIG. 6 is an output characteristic diagram of the conventional exhaust system. 1... 1st cylinder 2... 2nd cylinder 3...
3rd cylinder 4... 4th cylinder 5-8... Exhaust port 15.16... Exhaust passage group 17.18...
Main exhaust pipe 19...All cylinder gathering part 22.23...Sub-exhaust passage 27...Opening/closing valve 28...Branch part
40...CPU41~44...Main manifold 45...Submanifold, Sea Agent Patent attorney Ei 1) Yoshiaki 1'') Sagi,
−/ ′・, 17 1...1st Qi Question Saetsu Ward Method C] faction

Claims (1)

【特許請求の範囲】[Claims] （１）シリンダ内に開口する排気ポート開口部から全気
筒の排気通路集合部までの主排気通 路と、 上記主排気通路からそれぞれ分岐した副排 気通路とを設けると共に、 上記副排気通路には、該通路の分岐部から 上記集合部までの距離と略等長の位置に開 閉弁を設け、 上記開閉弁をエンジンの中速回転域以下で 閉弁制御する制御手段を備えた 多気筒エンジンの排気装置。(1) A main exhaust passage from the exhaust port opening opening into the cylinder to the exhaust passage gathering part of all cylinders, and sub-exhaust passages branched from the main exhaust passage are provided, and the sub-exhaust passage includes: An exhaust gas of a multi-cylinder engine, comprising an on-off valve at a position approximately equal in length to the distance from the branching part of the passage to the collecting part, and a control means for controlling the on-off valve to close at or below a medium speed rotation range of the engine. Device.