JPS5836822Y2 - Intake system for multi-cylinder engines - Google Patents

Description

【考案の詳細な説明】 本考案は、多気筒エンジンに釦ける吸気装置の改良に関
するものである。[Detailed Description of the Invention] The present invention relates to an improvement of an intake device for a multi-cylinder engine.

従来より、例えば特開昭５２−１１５９１７号に示され
るように、吸気通路を１次側吸気通路と２次側吸気通路
とに区画し、吸入空気量が少ないときには、上記１次側
吸気通路から吸入空気を供給して流速を向上し燃焼室に
スワールを生成する一方、吸入空気量の多いときには、
１次側吸気通路に加え２次側吸気通路からも吸入空気を
供給して出力の向上を図るようにした吸気装置は公知で
ある。Conventionally, as shown in Japanese Patent Application Laid-open No. 52-115917, for example, the intake passage is divided into a primary intake passage and a secondary intake passage, and when the amount of intake air is small, air is removed from the primary intake passage. While supplying intake air to improve the flow velocity and generate swirl in the combustion chamber, when the amount of intake air is large,
2. Description of the Related Art Intake devices are known that supply intake air from a secondary intake passage in addition to a primary intake passage to improve output.

しかるに、上記のような１次側釦よび２次側吸気通路を
有する吸気装置を備えた多気筒エンジンにかいては、各
気筒のスワールの大きさが不均一となり、燃焼性能が相
違し、点火時期、排気ガスの還流、空燃比等の各種制御
を行う場合に、燃焼性能の悪い気筒に合せて全体を制御
することになって、その効率が低下するとともに最適制
御が行えない不具合を有するものである。However, in a multi-cylinder engine equipped with an intake system having a primary side button and a secondary intake passage as described above, the size of swirl in each cylinder becomes uneven, combustion performance differs, and ignition When performing various controls such as timing, exhaust gas recirculation, air-fuel ratio, etc., the entire control is performed according to the cylinder with poor combustion performance, resulting in a decrease in efficiency and a problem in which optimal control cannot be performed. It is.

すなわち、第２図に多気筒エンジンとして４気筒エンジ
ンのシリンダヘッド５卦よび吸気マニホールド４の構造
を例示するように、吸気マニホールド４は気化器に接続
される主吸気管４ｅと、この主吸気管４ｅから各気筒に
分岐した分岐管４ａ〜４ｄとを有し、各分岐管４ａ〜４
ｄはその湾曲方向、湾曲率がそれぞれ異なっており、燃
焼室２ａ〜２ｄ内でスワールＳを生成するための１次側
吸気通路Ａは２次側吸気通路Ｂより細くかつ若干湾曲し
て形成され、燃焼室２ａ〜２ｄにその接線方向から吸入
空気を供給して周方向に旋回するスワール８１〜Ｓ４を
発生させるものである。That is, as shown in FIG. 2 illustrating the structure of the cylinder head 5 and intake manifold 4 of a four-cylinder engine as a multi-cylinder engine, the intake manifold 4 includes a main intake pipe 4e connected to a carburetor, and a main intake pipe 4e connected to a carburetor. It has branch pipes 4a to 4d branched from 4e to each cylinder, and each branch pipe 4a to 4
d have different curvature directions and curvature rates, and the primary intake passage A for generating swirl S in the combustion chambers 2a to 2d is narrower and slightly curved than the secondary intake passage B. , the intake air is supplied to the combustion chambers 2a to 2d from the tangential direction to generate swirls 81 to S4 that swirl in the circumferential direction.

そして、第１気筒の燃焼室２ａにかいては、吸気マニホ
ールド４の第１分岐管４ａの湾曲に沿う吸入空気の流れ
方向と１次側吸気通路Ａの湾曲方向とが一致し、大きな
スワールＳ１が発生する一方、第２気筒の燃焼室２ｂで
は両者の湾曲方向は一致するが第２分岐管４ｂの湾曲が
小さくなるため、スワールＳ２は若干小さくなり、第３
気筒の燃焼室２ｃでは第３分岐管４ｃと１次側吸気通路
Ａとの湾曲方向が反対方向となることから、さらにスワ
ールＳ３は小さくなり、第４気筒の燃焼室２ｄでは両者
の湾曲方向が反対でしかも第４分岐管４ｄの湾曲が大き
くなることにより、スワールＳ４は最も小さくなって、
第１気筒の燃焼室２ａに釦けるスワールＳ１とは大きな
差異を生じる結果、前記の如き不具合を有するものであ
る。In the combustion chamber 2a of the first cylinder, the flow direction of the intake air along the curve of the first branch pipe 4a of the intake manifold 4 matches the curve direction of the primary intake passage A, and a large swirl S1 On the other hand, in the combustion chamber 2b of the second cylinder, the curvature directions of both are the same, but the curvature of the second branch pipe 4b becomes smaller, so the swirl S2 becomes slightly smaller, and the third
In the combustion chamber 2c of the cylinder, the direction of curvature of the third branch pipe 4c and the primary intake passage A is opposite, so the swirl S3 is further reduced, and in the combustion chamber 2d of the fourth cylinder, the direction of curvature of both is opposite. On the contrary, as the curvature of the fourth branch pipe 4d increases, the swirl S4 becomes the smallest,
As a result, there is a large difference from the swirl S1 buttoned in the combustion chamber 2a of the first cylinder, resulting in the above-mentioned problems.

本考案はかかる点に鑑み、シリンダヘッドと吸気マニホ
ールドとの合せ面近傍の１次側吸気通路に通路断面積の
大きい拡大部を形成した多気筒エンジンの吸気装置を提
供し、各気筒の燃焼室で発生するスワールの均一化を図
って、前記従来の欠点を解消せんとするものである。In view of this, the present invention provides an intake system for a multi-cylinder engine in which an enlarged part with a large passage cross-sectional area is formed in the primary intake passage near the mating surface of the cylinder head and the intake manifold, and the combustion chamber of each cylinder is This is an attempt to eliminate the above-mentioned drawbacks of the conventional method by making the swirl generated in this method more uniform.

以下、本考案の実施例を図面に沿って説明する。Embodiments of the present invention will be described below with reference to the drawings.

第１図に示す多気筒エンジンにあ・いて、１は燃焼室２
に連通開口する吸気通路であり、吸気通路１はベンチュ
リ部３ａ、ノズル３ｂ、絞弁３Ｃ等を備えた気化器３を
有するとともに、吸気マニホールド４からシリンダヘッ
ド５内に形成された下流部分の燃焼室２近傍の吸気通路
１は、隔壁６によって、燃焼室２にスワールを生成する
ための通路面積の比較的小さい１次側吸気通路１ａと、
通路面積の比較的大きい２次側吸気通路１ｂとに区画さ
れ、２次側吸気通路１ｂの入口には制御弁７が設けられ
ている。In the multi-cylinder engine shown in Figure 1, 1 is the combustion chamber 2.
The intake passage 1 has a carburetor 3 equipped with a venturi part 3a, a nozzle 3b, a throttle valve 3C, etc. The intake passage 1 near the chamber 2 is formed by a partition wall 6 into a primary intake passage 1a having a relatively small passage area for generating swirl in the combustion chamber 2;
It is divided into a secondary intake passage 1b having a relatively large passage area, and a control valve 7 is provided at the entrance of the secondary intake passage 1b.

上記１次側吸気通路１ａは、７′リンダヘツド５と吸気
マニホールド４との合せ面ＦＫかけるシリンダヘッド５
側に通路断面積の大きい拡大部８が形成されて訃り、こ
の拡大部８に対する入口側の吸気マニホールド４内の１
次側吸気通路１ａの開口位置と、出口側のシリンダヘッ
ド５内の１次側吸気通路１ａの開口位置とには段差が設
けられ、該１次側吸気通路１ａの下流端は湾曲して２次
側吸気通路１ｂの下流端に開口し、接線方向から燃焼室
２に吸入空気（混合気）を供給してスワールを生成する
ものである。The primary side intake passage 1a is connected to the cylinder head 5 by the mating surface FK of the cylinder head 5 and the intake manifold 4.
An enlarged part 8 with a large passage cross-sectional area is formed on the side, and one part of the intake manifold 4 on the inlet side to this enlarged part 8
A step is provided between the opening position of the next side intake passage 1a and the opening position of the primary side intake passage 1a in the cylinder head 5 on the outlet side, and the downstream end of the primary side intake passage 1a is curved. It opens at the downstream end of the next intake passage 1b and supplies intake air (mixture) to the combustion chamber 2 from the tangential direction to generate a swirl.

一方、９は上記制御弁Ｉを開閉するダイヤフラム装置で
、該ダイヤフラム装置９にはその開作動源として吸気通
路１のベンチュリ部３ａのベンチュリ負圧を導くための
負正通路１０が接続され、吸入空気量が少ないときには
制御弁７を閉じて１次側吸気通路１ａのみから吸入空気
を供給する一方、吸入空気量が多いときにはベンチュリ
負圧の増大に応じて制御弁７を開き、１次側吸気通路１
ａに加え２次側吸気通路Ｔｂからも吸入空気を供給する
ものである。On the other hand, 9 is a diaphragm device that opens and closes the control valve I. A negative and positive passage 10 is connected to the diaphragm device 9 as an opening operation source for guiding the venturi negative pressure of the venturi portion 3a of the intake passage 1. When the amount of air is small, the control valve 7 is closed and intake air is supplied only from the primary intake passage 1a, while when the amount of intake air is large, the control valve 7 is opened in response to an increase in the venturi negative pressure, and the intake air is supplied from the primary side intake passage 1a. Passage 1
In addition to a, intake air is also supplied from the secondary intake passage Tb.

また、１１は上記吸気通路１の下流端を開閉する吸気弁
、１２は排気通路１３を開閉する排気弁であって、両弁
はカム１４、ロッカーアーム１５、バルブスプリング１
６等による動弁機構によって開閉される。Further, 11 is an intake valve that opens and closes the downstream end of the intake passage 1, and 12 is an exhaust valve that opens and closes the exhaust passage 13.
It is opened and closed by a valve mechanism such as 6.

尚、１７はシリンダブロック、１８はピストンである。Note that 17 is a cylinder block and 18 is a piston.

上記実施例の如き構成によれば、１次側吸気通路１ａを
流下する吸入空気には吸気マニホールド４の各分岐管を
流れることによって旋回方向の慣性が生起するが、この
吸入空気が拡大部８を通過する間に上記旋回方向の慣性
は拡散消去され、１次側吸気通路１ａの下流端近傍の湾
曲により各気筒で等しい大きさのスワールが生成される
。According to the configuration of the above embodiment, inertia in the swirling direction is generated in the intake air flowing down the primary side intake passage 1a by flowing through each branch pipe of the intake manifold 4, but this intake air flows into the enlarged portion 8. The inertia in the swirling direction is diffused and eliminated while passing through the cylinder, and a swirl of the same size is generated in each cylinder due to the curvature near the downstream end of the primary intake passage 1a.

また、拡大部８０入口側と出口側とには段差が設けであ
ることにより、拡大部８に流入した吸入空気（混合気）
はその壁面に衝突して燃料の霧化が促進される。In addition, since there is a step between the inlet side and the outlet side of the enlarged part 80, the intake air (air mixture) flowing into the enlarged part 8
collides with the wall and atomization of the fuel is promoted.

さらに、拡大部８をシリンダヘッド５の合せ面Ｆに形成
することにより、拡大部８の形成は容易に行える。Further, by forming the enlarged portion 8 on the mating surface F of the cylinder head 5, the enlarged portion 8 can be easily formed.

尚、上記拡大部８の入口側と出口側との段差は必須のも
のではなく、１次側吸気通Ｆ＠ｌａの途中を単に拡大し
たものでもスワールの均−化作田は十分にある。It should be noted that the level difference between the inlet side and the outlet side of the enlarged portion 8 is not essential, and simply enlarging the middle of the primary side intake air passage F@la is sufficient to equalize the swirl.

拡大部８の配設位置は、合せ面Ｆの吸気マニホールド４
側でもよく、この合せ面Ｆの近傍に３いて吸気マニホー
ルド４の分配湾曲の下流側に設ければよいものである。The expanded portion 8 is located at the intake manifold 4 on the mating surface F.
It may be provided near the mating surface F on the downstream side of the distribution curve of the intake manifold 4.

斗た、上記実施例では１次側吸気通路１ａと２次側吸気
通路１ｂとの区画は吸気通路１の下流側部分のみで行っ
ているが、上流側部分を含めて吸気通路全体を１次側吸
気通路と２次側吸気通路とに区画し１次および２次気化
器を備えたものでもよく、さらに、１次側吸気通路と２
次側吸気通路とを各々独立して燃焼室に開口させて各々
吸気弁で開閉するようにしたものにも適用可能である。In addition, in the above embodiment, the primary side intake passage 1a and the secondary side intake passage 1b are divided only in the downstream part of the intake passage 1, but the entire intake passage including the upstream part is divided into the primary side intake passage 1a and the secondary side intake passage 1b. It may be divided into a side intake passage and a secondary side intake passage and equipped with a primary and secondary carburetor.
It is also applicable to a configuration in which the next intake passages are each independently opened into the combustion chamber and each is opened and closed by an intake valve.

従って、以上の如き本考案によれば、シリンダヘッドと
吸気マニホールドとの合せ面近傍の１次側吸気通路に通
路断面積の大きい拡大部を設けたことにより、この拡大
部で吸気マニホールドを流下するのに伴って生じた吸入
空気の旋回方向の慣性を拡散消去してスワールへの影響
をなくし、多気筒エンジンの各気筒における燃焼室に均
一なスワールを生成することができ、各気筒の燃焼性能
を同一にして、点火時期、排気ガスの還流等の各種制御
を最適に効率良く行うことができ、吸気通路を１次側吸
気通路と２次側吸気通路とに区画する所期の特性が十分
に発揮できるものである。Therefore, according to the present invention as described above, by providing an enlarged portion with a large passage cross-sectional area in the primary side intake passage near the mating surface of the cylinder head and the intake manifold, the air flows down the intake manifold at this enlarged portion. By diffusing and eliminating the inertia in the swirling direction of the intake air that occurs due to this, it eliminates the effect on swirl, and it is possible to generate a uniform swirl in the combustion chamber of each cylinder of a multi-cylinder engine, improving the combustion performance of each cylinder. By keeping the same, various controls such as ignition timing and exhaust gas recirculation can be performed optimally and efficiently, and the desired characteristics of dividing the intake passage into the primary intake passage and the secondary intake passage are sufficient. It is something that can be demonstrated.

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

第１図は本考案の一実施例の吸気装置を備えた多気筒エ
ンジンの断面図、第２図は従来の多気筒エンジンに釦け
るシリンダヘッドと吸気マニホールドの底面図である。 １・・・・・・吸気通路、１ａ・・・・・・１次側吸気
通路、１ｂ・・・・・・２次側吸気通路、２・・・・・
・燃焼室、３・・・・・・気化器、４・・・・・・吸気
マニホールド、５・・・・・・シリンダヘッド、６・・
・・・・隔壁、ｒ・・・・・・制御弁、８・・・・・・
拡大部、９・・・・・・ダイヤフラム装置、１０・・・
・・・負圧通路、１１・・・・・・吸気弁、Ｆ・・・・
・・合せ面。FIG. 1 is a sectional view of a multi-cylinder engine equipped with an intake system according to an embodiment of the present invention, and FIG. 2 is a bottom view of the cylinder head and intake manifold of a conventional multi-cylinder engine. 1...Intake passage, 1a...Primary side intake passage, 1b...Secondary side intake passage, 2...
・Combustion chamber, 3... Carburizer, 4... Intake manifold, 5... Cylinder head, 6...
...Bulkhead, r...Control valve, 8...
Enlarged section, 9...Diaphragm device, 10...
...Negative pressure passage, 11...Intake valve, F...
...Matching surface.

Claims (1)

【実用新案登録請求の範囲】[Scope of utility model registration request] シリンダヘッドと吸気マニホールドとにより形成される
燃焼室近傍の吸気通路を燃焼室にスワールを生成するた
めの１次側吸気通路と２次側吸気通路とに区画し、吸入
空気量が少ないときには上記１次側吸気通路のみから吸
入空気を供給する一方、吸入空気量が多いときには上記
１次側吸気通路に加え２次側吸気通路からも吸入空気を
供給するようにした多気筒エンジンの吸気装置に訟いて
、上記シリンダヘッドと吸気マニホールドとの合せ面近
傍の１次側吸気通路に通路断面積の大きい拡大部を形成
したことを特徴とする多気筒エンジンの吸気装置。The intake passage near the combustion chamber formed by the cylinder head and intake manifold is divided into a primary intake passage and a secondary intake passage for generating swirl in the combustion chamber. The problem is that the intake system of a multi-cylinder engine is designed to supply intake air only from the next intake passage, but when the amount of intake air is large, to supply intake air from the secondary intake passage in addition to the above-mentioned primary intake passage. An intake system for a multi-cylinder engine, characterized in that an enlarged portion having a large passage cross-sectional area is formed in the primary side intake passage near the mating surface of the cylinder head and the intake manifold.