JPH0217687B2

JPH0217687B2 -

Info

Publication number: JPH0217687B2
Application number: JP55167693A
Authority: JP
Inventors: Wataru Yamamoto
Original assignee: Suzuki Motor Corp
Current assignee: Suzuki Motor Corp
Priority date: 1980-11-28
Filing date: 1980-11-28
Publication date: 1990-04-23
Also published as: JPS5791320A

Description

【発明の詳細な説明】本発明は、一の燃焼室に対して吸気弁を２つ有
する４サイクル内燃機関の吸気装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for a four-stroke internal combustion engine having two intake valves for one combustion chamber.

２吸気弁式の内燃機関は従来より種々あるが、
従来のものはこの２つの吸気弁を開閉する機構が
別途独立して設けられていたため、動弁機構がか
なり複雑なものとなつていた。 There are various types of internal combustion engines with two intake valves, but
In the conventional type, a mechanism for opening and closing these two intake valves was provided separately and independently, making the valve operating mechanism quite complicated.

また、最近は、排ガス対策の関係もあつて、燃
焼室に吸気のスワールを発生させることが多い
が、従来の２吸気弁式のものは、この両方から吸
気されるときに互いのスワールが打ち消し合うよ
うな配置関係となつていたため、全負荷域に渡つ
て十分な吸気のスワールを得ることができなかつ
た。 Additionally, recently, intake swirl is often generated in the combustion chamber due to exhaust gas countermeasures, but in conventional two-intake valve systems, when air is taken in from both sides, the swirls cancel each other out. Because the arrangement was such that it matched, it was not possible to obtain sufficient intake air swirl across the entire load range.

したがつて、本発明の目的は、動弁機構を簡単
化すると共に、全負荷域に渡つて十分な吸気のス
ワールが得られる内燃機関の吸気装置を提供する
ことを目的とする。 SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an intake system for an internal combustion engine that simplifies a valve mechanism and provides sufficient intake air swirl over the entire load range.

また、本発明の他の目的は、燃料供給装置を適
宜選択するだけで、全体的に均一な混合化の混合
気を燃焼させる方式と、濃混合気と希薄混合気と
を層状に供給して燃焼させる層状燃焼方式とのい
ずれをも採択し得る内燃機関の吸気装置を提供す
ることを目的とする。 Another object of the present invention is to provide a method for combusting an overall uniform mixture by simply selecting a fuel supply device appropriately, and a method for supplying a rich mixture and a lean mixture in layers. An object of the present invention is to provide an intake system for an internal combustion engine that can adopt either a stratified combustion method or a stratified combustion method.

以下に本発明の実施例を図面に基いて説明す
る。第１図、第２図において、１はシリンダ、２
はシリンダヘツド、３はピストン、４は燃焼室で
あり、シリンダヘツド２には、それぞれ独立して
第１吸気ポート５及び第２吸気ポート６が形成さ
れている。この両吸気ポート５，６は、ここを通
つた混合気が、燃焼室４内でシリンダ１の軸心を
中心とするスワール（渦流）状となるように該燃
焼室４に指向して開口され、該スワールの旋回方
向は、両吸気ポート５，６からの混合気共に同一
方向（第１図反時計方向）となるようにされてい
る。このような両吸気ポート５，６は、その一端
がシリンダヘツド２の同一外端面すなわち吸気マ
ニホルド７の接続端面２ａに開口され、またその
他端は、第１吸気ポート５が上記接続端面２ａに
近い側に、第２吸気ポート６が上記接続端面２ａ
に遠い側において燃焼室４に開口され、該両他端
の開口方向は、第２図に示すようにシリンダ１の
軸心Ｏとほぼ平行となるようにしてピストン３の
頂面に対向している。そして、第１吸気ポート５
の有効開口面積は、第２吸気ポート６の有効開口
面積より大きくされている。 Embodiments of the present invention will be described below with reference to the drawings. In Figures 1 and 2, 1 is a cylinder, 2
3 is a cylinder head, 3 is a piston, and 4 is a combustion chamber. The cylinder head 2 is independently formed with a first intake port 5 and a second intake port 6. Both intake ports 5 and 6 are opened toward the combustion chamber 4 so that the air-fuel mixture passing through them forms a swirl around the axis of the cylinder 1 within the combustion chamber 4. The swirl direction is such that the air-fuel mixture from both intake ports 5 and 6 is in the same direction (counterclockwise in FIG. 1). One end of both intake ports 5 and 6 is opened at the same outer end surface of the cylinder head 2, that is, the connecting end surface 2a of the intake manifold 7, and the other end is opened at the same outer end surface of the cylinder head 2, that is, the connecting end surface 2a of the intake manifold 7. On the side, the second intake port 6 is connected to the connection end surface 2a.
It opens into the combustion chamber 4 on the far side, and the opening directions of the other ends are substantially parallel to the axis O of the cylinder 1, as shown in FIG. There is. And the first intake port 5
The effective opening area of the second intake port 6 is larger than that of the second intake port 6.

８は第１吸気ポートを開閉する第１吸気弁、９
は第２吸気ポートを開閉する第２吸気弁であり、
該両吸気弁８，９の中心を結ぶ線l₁は、第１図に
示すように吸気マニホルド接続端面２ａに対して
ほぼ直角となつている。また、第１図中１０は排
気弁、１１は点火プラグであり、各構成要素８，
９，１０，１１の燃焼室４内における配置関係
は、第１図に示すように、シリンダ１の軸心Ｏを
通つて吸気マニホルド接続端面２ａと直交する線
l₂をほぼ境として、両吸気弁８，９はその片側に
（第１図右寄り）に、また排気弁１０が他側に位
置し、かつ点火プラグ１１は、軸心Ｏに対して接
続端面２ａと反対側に位置している。したがつ
て、第１吸気ポート５からの混合気は、第５図に
符号Ａの矢印で示すように、第２吸気弁９、点火
プラグ１１を順次掃過した後排気弁１０へ向けて
流れ、また第２吸気ポート６からの混合気は、第
６図に符号Ｂの矢印で示すように点火プラグ１１
を掃過したのみで排気弁１０へ向けて流れること
となる。勿論、両吸気ポート５，６からの混合気
は、符号Ａ，Ｂ，Ｃの矢印で示すように第２図下
方へ向けても指向されるので、吸気のスワール
は、第２図同一水平面を旋回するのではなく、ピ
ストン４に向かつてスパイラル状となつて旋回す
る。 8 is a first intake valve that opens and closes the first intake port; 9
is a second intake valve that opens and closes the second intake port,
A line _l1 connecting the centers of both intake valves 8 and 9 is approximately perpendicular to the intake manifold connecting end surface 2a, as shown in FIG. Further, in FIG. 1, 10 is an exhaust valve, 11 is a spark plug, and each component 8,
The arrangement relationship of 9, 10, and 11 in the combustion chamber 4 is as shown in FIG. 1, as shown in FIG.
With l ₂ as the approximate boundary, both intake valves 8 and 9 are located on one side (toward the right in Figure 1), and the exhaust valve 10 is located on the other side, and the spark plug 11 is located at its connecting end face with respect to the axis O. It is located on the opposite side from 2a. Therefore, the air-fuel mixture from the first intake port 5 sequentially sweeps the second intake valve 9 and the spark plug 11, and then flows toward the exhaust valve 10, as shown by the arrow A in FIG. , and the air-fuel mixture from the second intake port 6 is directed to the spark plug 11 as shown by the arrow B in FIG.
It flows toward the exhaust valve 10 only by sweeping the air. Of course, the air-fuel mixture from both intake ports 5 and 6 is also directed downward in FIG. Rather than turning, it turns in a spiral toward the piston 4.

前記両吸気弁５，６は、第２図に示すように一
のカム１２によつて駆動される同一のロツカアー
ム１３に対して係合、すなわち２つの吸気弁６，
６に対して一のロツカアーム１３のみが設けられ
ている。第２図に示すように、ロツカアーム１３
は、支軸（カムシヤフト）１４に直角に設置され
ている。そして両吸気弁５，６のステム５ａ，６
ａとロツカアーム１３との当接点X₁，X₂は、該
ロツカアーム１３の支軸１４からの距離が異なつ
ており、支軸１４とX₁との距離S₁が、支軸１４
とX₂との距離S₂よりも大きくなつている。した
がつて、第１吸気弁８のリフト（第２図上下変位
置）は、第２吸気弁９のリフトよりも大きくなつ
ている。すなわち、第３図に示すように、第１吸
気弁８のリフトをP₁とすると、第２吸気弁９の
リフトP₂は、P₁×S₂／S₁の大きさとなつている。 Both the intake valves 5, 6 are engaged with the same rocker arm 13 driven by one cam 12, as shown in FIG.
Only one rocker arm 13 for six is provided. As shown in FIG.
is installed at right angles to the support shaft (camshaft) 14. and stems 5a, 6 of both intake valves 5, 6.
The contact points X ₁ and X ₂ between a and the rocker arm 13 are different in distance from the support shaft 14 of the rocker arm 13, and the distance S 1 between the support shaft 14 and X ₁ is different from the distance S 1 between the support shaft ₁₄ and the support shaft 14.
The distance between and X ₂ is greater than S ₂ . Therefore, the lift of the first intake valve 8 (in the vertical position in FIG. 2) is larger than the lift of the second intake valve 9. That is, as shown in FIG. 3, if the lift of the first intake valve 8 is _P1 , the lift _P2 of the second intake valve 9 has a magnitude of _P1 × _S2 / _S1 .

上記両吸気ポート５，６に対しては、吸気マニ
ホルド７を介して、全負荷域に渡つて混合気が一
の通風路に生成される燃料供給装置、例えば１バ
レル気化器１５が接続されている。そして、第１
吸気ポート５内には、高負荷時にのみ開となる開
閉弁１６が設けられており、実施例では、開閉弁
１６と気化器１５のスロツトル弁１７とを連動さ
せるようにしてある。 A fuel supply device, for example, a one-barrel carburetor 15, which generates an air-fuel mixture in one ventilation passage over the entire load range is connected to both the intake ports 5 and 6 through the intake manifold 7. There is. And the first
An on-off valve 16 that opens only when the load is high is provided in the intake port 5, and in the embodiment, the on-off valve 16 and the throttle valve 17 of the carburetor 15 are linked.

次に、上記構成の作用について説明する。エン
ジンを始動すると、第１、第２の吸気弁５，６共
に、一のロツカアーム１３を介して開閉される。
いま、低負荷時にあつては、開閉弁１６が閉じて
いるため、気化器１５で生成された混合気は、吸
気マニホルド７を通つた後全て第２吸気ポート６
より燃焼室４に供給される。そして、第２吸気弁
９のリフトは小さい（開弁時の第２吸気弁９とそ
のバルブシートとの間の間隙が少さい）ため、低
負荷時にように混合気量が少なくても速い流速が
得られ、強力な吸気のスワールを得ることができ
る。また、この第２吸気ポート６からの混合気
は、第５図に符号Ａの矢印で示すように、第１吸
気弁８に何等邪摩されずに点火プラグ１１へ向け
て流れるので、上記強いスワールを維持すること
ができる。 Next, the operation of the above configuration will be explained. When the engine is started, both the first and second intake valves 5 and 6 are opened and closed via one rocker arm 13.
Now, when the load is low, the on-off valve 16 is closed, so all the air-fuel mixture generated in the carburetor 15 passes through the intake manifold 7 and then flows into the second intake port 6.
is supplied to the combustion chamber 4. Since the lift of the second intake valve 9 is small (the gap between the second intake valve 9 and its valve seat is small when the valve is open), the flow rate is high even when the amount of air-fuel mixture is small, such as during low load. is obtained, and a powerful intake swirl can be obtained. Furthermore, as shown by the arrow A in FIG. 5, the air-fuel mixture from the second intake port 6 flows toward the spark plug 11 without any interference from the first intake valve 8, so Swirl can be maintained.

また、高負荷時、特に全負荷時には開閉弁１６
が全開となり、気化器１５で生成された混合気
は、両吸気ポート５，６を共に流れて燃焼室４へ
供給される。このとき、第２吸気弁９のリフトが
大きいため、充分な量の混合気を燃焼室４へ供給
することができる。そして、両吸気ポート５，６
によつて形成される吸気のスワールは、互いに助
長し合つて、強力なスワールを生成する（第６図
の符号Ａ，Ｂ，Ｃの矢印参照）。このように実際
の吸入空気は、第６図に符号Ａ，Ｂ，Ｃで示すよ
うにピストン方向に渦を巻きながら、螺旋状に降
りていくが付号８で示す第１吸気弁８のようにシ
リンダの内壁付近まで開口している場合には、吸
入されてすぐ内壁に当り内壁を伝わりながら下方
に向かうことになる。 Also, at high loads, especially at full loads, the on-off valve 16
is fully opened, and the air-fuel mixture generated in the carburetor 15 flows through both intake ports 5 and 6 and is supplied to the combustion chamber 4. At this time, since the lift of the second intake valve 9 is large, a sufficient amount of air-fuel mixture can be supplied to the combustion chamber 4. And both intake ports 5, 6
The swirls of the intake air formed by the above-mentioned effects promote each other to produce a strong swirl (see arrows A, B, and C in FIG. 6). In this way, the actual intake air spirals in the direction of the piston, as shown by symbols A, B, and C in FIG. If the opening is close to the inner wall of the cylinder, the inhaled gas will immediately hit the inner wall and travel down the inner wall.

第４図は本発明の他の実施例を示し、燃料供給
装置として、高負荷用と低負荷用との２つの独立
した通風路を有するものを用いた場合を示し、実
施例では高負荷用（二次側）通風路１８ａと低負
荷用（一次側）通風路１８ｂとを有する２バレル
気化器１８を用いてある。そして、吸気マニホル
ド７′も、高負荷用通路７′ａと低負荷用通路７′
ｂとを有するものが用いられ、これに伴つて、前
記実施例における開閉弁１６を廃したものとなつ
ている。本実施例では、気化器１８そのものの分
配作用によつて、燃焼室４には、低負荷時には第
２吸気ポート６からのみ混合気が供給され、また
高負荷時には両吸気ポート５，６から混合気が供
給される。 FIG. 4 shows another embodiment of the present invention, in which a fuel supply device having two independent ventilation passages, one for high load and one for low load, is used. A two-barrel vaporizer 18 having a (secondary side) ventilation passage 18a and a low-load (primary side) ventilation passage 18b is used. The intake manifold 7' also has a high load passage 7'a and a low load passage 7'.
b is used, and accordingly, the on-off valve 16 in the previous embodiment is omitted. In this embodiment, due to the distribution action of the carburetor 18 itself, the air-fuel mixture is supplied to the combustion chamber 4 only from the second intake port 6 at low loads, and the mixture is supplied from both intake ports 5 and 6 at high loads. Qi is supplied.

本発明は、この他、燃料供給装置として、濃い
混合気を生成する一の通風路と、薄い混合気を生
成する他の通風路とを有する層状燃焼用のものを
用いることによつて、層状燃焼を行わせることが
できる。すなわち、第４図のものにおいて、通風
路１８ａに薄い混合気を供給し、通風路１８ｂに
濃い混合気を供給するようにし、全負荷域に渡つ
て該両通風路１８ａ，１８ｂから濃、薄両方の混
合気を同時に供給すればよい。このとき、燃焼室
４には、第１吸気ポート５からは薄い混合気が供
給され、また第２吸気ポートからは濃い混合気が
供給され、これによつて、燃焼室４には、シリン
ダ１の半径方向外側に濃い混合気の層がまた内側
に薄い混合気の層が形成される。そして、点火プ
ラグ１１によつて、先ず外側の濃い混合気の層に
着火され、次いでこの着火した濃混合気の火炎に
よつて内側の薄い混合気の層が確実に着火され
る。 In addition, the present invention provides stratified combustion by using a fuel supply device for stratified combustion, which has one ventilation passage for producing a rich mixture and another ventilation passage for producing a lean mixture. Combustion can occur. That is, in the case of FIG. 4, a lean mixture is supplied to the ventilation passage 18a, a rich mixture is supplied to the ventilation passage 18b, and rich and lean mixtures are supplied from both ventilation passages 18a and 18b over the entire load range. It is sufficient to supply both mixtures at the same time. At this time, the combustion chamber 4 is supplied with a lean mixture from the first intake port 5 and a rich mixture from the second intake port. A layer of rich mixture is formed on the outside in the radial direction, and a layer of thin mixture is formed on the inside. First, the outer rich mixture layer is ignited by the spark plug 11, and then the inner thin mixture layer is reliably ignited by the flame of the ignited rich mixture.

本発明は以上述べたことから明らかなように、
２つの吸気弁の動弁機構が簡単になる。また第
１、第２の吸気ポートのそれぞれを吸気マニホル
ド取付面に対して直角に配置したものであるか
ら、２つある吸気弁から同時に混合気が吸入され
た場合、生成される吸入スワールの方向が同じも
のとなり、全負荷時においても燃焼室に強力なス
ワールが得られることになる。また両吸気ポート
が平行に配置されているときのように、低負荷時
から高負荷時に移行する際に生ずる、互いのスワ
ールが打消し合うということも生じない。そして
更に、層状燃焼あるいは均一混合比燃焼のいずれ
にも適用できるという効果を奏する。 As is clear from the above description, the present invention has the following features:
The valve operating mechanism for the two intake valves is simplified. Furthermore, since the first and second intake ports are arranged perpendicularly to the intake manifold mounting surface, the direction of the intake swirl generated when air-fuel mixture is drawn from the two intake valves at the same time are the same, and a strong swirl can be obtained in the combustion chamber even under full load. Further, unlike when both intake ports are arranged in parallel, the swirls that occur when transitioning from a low load to a high load do not cancel each other out. Furthermore, the present invention has the advantage that it can be applied to either stratified combustion or uniform mixture ratio combustion.

そしてこのような作用効果に加え、ロツカアー
ムをカムシヤフトに対して直角に設置したことに
より、ボア間ピツチを著しく小さくすることがで
き、ひいては全体的に小型な内燃機関とすること
ができる効果も得られることになる。 In addition to these effects, by installing the rocker arm at right angles to the camshaft, it is possible to significantly reduce the pitch between the bores, which in turn has the effect of making the internal combustion engine smaller overall. It turns out.

[Brief explanation of drawings]

第１図は本発明の一実施例を示すもので、シリ
ンダヘツドをその内面側からみた一部断面図、第
２図は第１図ほぼ−線に沿う断面図、第３図
は吸・排気弁のリフトの関係を示す図、第４図は
本発明の他の実施例を示すもので、第１図に対応
した部分の一部断面図、第５図および第６図は混
合気の流れを説明するための説明図である。１……シリンダ、２……シリンダヘツド、２ａ
……吸気マニホルド接続端面、４……燃焼室、５
……第１吸気ポート、６……第２吸気ポート、８
……第１吸気弁、９……第２吸気弁、１０……排
気弁、１１……点火プラグ、１２……カム、１３
……ロツカアーム、１５，１８……気化器、１６
……開閉弁、Ｏ……軸心、l₁，l₂……線。 Fig. 1 shows an embodiment of the present invention, in which a partial sectional view of a cylinder head is seen from its inner surface, Fig. 2 is a sectional view taken approximately along the - line in Fig. 1, and Fig. 3 shows an intake/exhaust cylinder head. FIG. 4 is a diagram showing the relationship between valve lifts, and shows another embodiment of the present invention. FIG. 4 is a partial cross-sectional view of a portion corresponding to FIG. 1, and FIGS. It is an explanatory diagram for explaining. 1...Cylinder, 2...Cylinder head, 2a
...Intake manifold connection end surface, 4...Combustion chamber, 5
...First intake port, 6...Second intake port, 8
...First intake valve, 9...Second intake valve, 10...Exhaust valve, 11...Spark plug, 12...Cam, 13
...Lotsuka arm, 15, 18... Carburizer, 16
...Opening/closing valve, O...Axis, _l1 , _l2 ...Line.

Claims

[Scope of Claims] 1. First intake ports each formed in the cylinder head and each opening oriented toward one combustion chamber so as to generate a swirl of intake air in the same direction around the axis of the cylinder; A first intake valve that opens and closes the first intake port and that engages with a second intake port and the same rocker arm driven by one cam, respectively, and that opens and closes the second intake port and the first intake valve that opens and closes the second intake port. a second intake valve having a lift smaller than that of the intake valve; the first intake valve, the second intake valve, the spark plug, and the exhaust valve are arranged in this order in the direction of swirl of the intake air;
One end of each of the two intake ports opens on the same outer surface of the cylinder head, while the other end of the first intake port opens on a side closer to the same outer surface of the cylinder head, and the other end of the first intake port opens on the same outer surface of the cylinder head. The rocker arm is formed such that its end opens into the combustion chamber on the side far from the same outer surface of the cylinder head, and a line connecting the centers of the two intake valves is substantially perpendicular to the same outer surface of the cylinder head. An intake system for an internal combustion engine, characterized in that the intake system is installed perpendicularly to a camshaft. 2. In the intake system for an internal combustion engine according to claim 1, both the intake valves are located on one side of a line that passes through the axis of the cylinder and is orthogonal to the same outer end surface of the cylinder head. , an exhaust valve is located on the other side, and the spark plug is located on the opposite side of the same outer end surface of the cylinder head with respect to the axis of the cylinder. 3. In the intake system for an internal combustion engine according to claim 1 or 2, one ventilation passage supplies air-fuel mixture to both the first and second intake ports over the entire load range. A fuel supply device having a fuel supply device is connected to the fuel supply device, and the first intake port is provided with an on-off valve that operates according to the load. 4. In the intake system for an internal combustion engine according to claim 1 or 2, the fuel supply system is one having independent ventilation passages for low load use and high load use, and the fuel supply apparatus A high-load ventilation passage is connected to the first intake port, and a low-load ventilation passage is connected to the second intake port. 5. In the intake system for an internal combustion engine according to claim 1 or 2, the fuel supply device includes a rich air-fuel mixture ventilation passage for producing a rich air-fuel mixture and a ventilation passage for a rich air-fuel mixture for producing a lean air-fuel mixture. A ventilation passage for a lean mixture is used, the ventilation passage for a rich mixture is connected to the second intake port, and the ventilation passage for a lean mixture is connected to the first intake port.