JPS589246B2 - engine - Google Patents

Description

【発明の詳細な説明】 本発明は、エンジン特に自動車用エンジンの改良に関す
るものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in engines, particularly automobile engines.

従来の自動車用エンジンでは、アイドル運転時及び軽負
荷運転時に、スロットル弁の開度が小さく吸気量が少量
であるため、吸入行程において吸気マニホルドからシリ
ンダ内に流入する混合気の速度が低く、従ってシリンダ
内における混合気のスワ−ルも弱い。In conventional automobile engines, during idle operation and light load operation, the opening of the throttle valve is small and the amount of intake air is small, so the speed of the air-fuel mixture flowing into the cylinder from the intake manifold during the intake stroke is low. The swirl of the air-fuel mixture inside the cylinder is also weak.

この結果、通常圧縮行程の終期に行なわれる点火時に、
シリンダ内に残存する混合気のスワールも弱くなり、着
火及び燃焼性が低くなるので、安定なエンジンの運転を
確保するだめには中及び高負荷運転時よりも空燃比が小
さい混合気を供給する必要があり、燃費の増大を招くだ
けでなく、濃混合気の不完全燃焼のだめに排ガス中のＣ
Ｏ，ＨＣが増加する不都合がある。As a result, at the time of ignition, which normally occurs at the end of the compression stroke,
The swirl of the air-fuel mixture remaining in the cylinder also becomes weaker, resulting in lower ignition and combustibility, so in order to ensure stable engine operation, a mixture with a lower air-fuel ratio than during medium and high load operation is supplied. This not only increases fuel efficiency, but also reduces C in exhaust gas due to incomplete combustion of rich mixture.
There is a disadvantage that O and HC increase.

又近来エンジンの排ガス中のＣＯ，ＨＣ特にＮＯｘを減
少させることを目的として、理論混合比よりも充分希薄
な混合気を燃焼させることが提案され、また排ガス中の
ＮＯｘを減少させることを目的として排ガスの一部をエ
ンジンの排気系から抽出して混合気中に混合し燃焼させ
ることも提案されているが、何れの場合にも混合気の着
火性、燃焼性が低くなるために、アイドル運転及び軽負
荷運転時におけるドライバビリティが低下し、燃費も悪
化する不都合があった。Recently, in order to reduce CO, HC, and especially NOx in engine exhaust gas, it has been proposed to burn a mixture that is sufficiently leaner than the stoichiometric mixture ratio. It has also been proposed to extract part of the exhaust gas from the engine's exhaust system and mix it into the air-fuel mixture for combustion, but in either case, the ignitability and combustibility of the air-fuel mixture will be low, making it difficult to operate the engine at idle. Also, drivability during light load operation is reduced, and fuel efficiency is also reduced.

特公昭４７−２４０４１号及び特開昭５０−３７９０７
号に示される先行技術は、濃混合気と空気又は希薄混合
気とを別経路でシリンダ内に吸入し、両者は着火時点ま
で混合されないようにして、着火直前には濃混合気を点
火プラグ周辺に導ひき、空気又は希薄混合気は点火プラ
グから離れだ場所に導びき、濃混合気に点火して着火燃
焼性を良好にし、総合の空燃比が犬の希薄燃焼を達成す
るものであるが、このような技術によれば運転状態に関
係なく常に良好な層状化を達成し 点火プラグ付近に濃
混合気を導びくだめに装置及び制御が複雑になるという
欠点がある。Japanese Patent Publication No. 47-24041 and Japanese Patent Publication No. 50-37907
The prior art shown in the No. 1 sucks a rich mixture and air or a lean mixture into the cylinder through separate routes, prevents the two from mixing until the point of ignition, and immediately before ignition, the rich mixture is sucked into the cylinder around the spark plug. The air or lean mixture is guided to a location away from the spark plug, ignites the rich mixture, improves ignition combustibility, and achieves a lean burn with an overall air-fuel ratio. However, this technique has the disadvantage that the device and control become complicated in order to always achieve good stratification regardless of the operating condition and to guide a rich mixture near the spark plug.

本発明は、シリンダ内に気体を噴射する簡単な副吸気系
を付加することで着火燃焼性を改善するもので、上記層
状燃焼とは全く異なる燃焼方式の改良に関するものであ
る。The present invention improves ignition combustibility by adding a simple sub-intake system that injects gas into the cylinder, and relates to an improvement in a combustion method that is completely different from the stratified combustion described above.

本発明の主たる目的は、特にアイドル及び軽負荷運転時
における燃費を改善し得る乗物用エンジンを提供するこ
とにある。A primary object of the present invention is to provide a vehicle engine that can improve fuel efficiency, particularly during idling and light load operation.

本発明の他の目的は、通常のエンジンではアイドル及び
軽負荷時において安定した運転が困難な希薄混合気を安
定的に燃焼させることができ、この結果として排ガス中
の有害成分が少い乗物用のエンジンを提供することにあ
る。Another object of the present invention is to be able to stably burn a lean air-fuel mixture that is difficult to operate stably at idle and under light load in a normal engine, and as a result, to reduce harmful components in exhaust gas. Our goal is to provide the following engines.

本発明のさらに他の目的は、通常のエンジンではアイド
ル及び軽負荷時において安定した運転が困難な、多量の
還流排ガスを含む混合気を安定的に燃焼させることがで
き、この結果として排ガス中のＮＯｘを減少し得る乗物
用のエンジンを提供することにある。Still another object of the present invention is to be able to stably burn a mixture containing a large amount of recirculated exhaust gas, which is difficult to operate stably at idle and under light load in a normal engine. An object of the present invention is to provide a vehicle engine capable of reducing NOx.

本発明の他の目的は、大きな出力の低下、ドライバビリ
テイの悪化、燃料悪化等の不具合を伴なうことなく希薄
混合気又は多量の還流排ガスを含む混合気を安定的に燃
焼させ得る乗物用エンジンを提供することにある。Another object of the present invention is to provide a vehicle capable of stably burning a lean mixture or a mixture containing a large amount of recirculated exhaust gas without causing problems such as a large decrease in output, deterioration of drivability, and deterioration of fuel. The goal is to provide engines for

本発明の更に他の目的は、アイドリンク及び低速低負荷
の軽負荷運転領域で排ガス中の有害ガス成分を従来のエ
ンジンより低減し得る乗物用エンジンを提供することに
ある。Still another object of the present invention is to provide a vehicle engine that can reduce harmful gas components in exhaust gas in idle link and low-speed, low-load light-load operating regions compared to conventional engines.

上記本発明の諸目的は燃焼室内に点火プラグのスパーク
ギャップを臨ませるとともに、同スパークギャップの近
傍に上記燃焼室の設定方向に指向して空気、混合気、排
気ガス等の気体を噴射する噴射孔を設けたエンジンにお
いて、上記燃焼室に主吸気弁を介して吸気を供給する主
吸気通路、同主吸気通路に設けられ吸気流量を制御する
絞り弁、上記噴射孔に常時連通するとともに上記主吸気
通路とは別個に設けられ絞りを介して吸気流量が制限さ
れる副吸気通路、同副吸気通路と並列に設けられ絞りを
介して吸気流量が制限されるバイパス通路及び同バイパ
ス通路を開閉する制御弁を備え、上記制御弁は上記主吸
気通路に設けられた絞り弁が全閉時にはその上流にあり
同絞り弁が部分開時にはその下流になる位置の負圧に応
じて開閉され、上記絞り弁が部分開時に上記制御弁が最
大開度となるように構成されたことを特徴とするエンジ
ンにより効果的に達成される。The objects of the present invention are to provide an injection method that allows the spark gap of the ignition plug to face into the combustion chamber, and injects gas such as air, air-fuel mixture, exhaust gas, etc. in the vicinity of the spark gap toward the set direction of the combustion chamber. In an engine provided with holes, a main intake passage supplies intake air to the combustion chamber via a main intake valve, a throttle valve provided in the main intake passage for controlling the intake air flow rate, and a throttle valve provided in the main intake passage to control the intake air flow rate; A sub-intake passage which is provided separately from the intake passage and whose intake flow rate is restricted via a throttle, a bypass passage which is provided in parallel with the sub-intake passage and whose intake flow rate is restricted through a restriction, and which opens and closes the bypass passage. A control valve is provided, and the control valve opens and closes in response to negative pressure at a position upstream of the throttle valve provided in the main intake passage when the throttle valve is fully closed and downstream of the throttle valve when the throttle valve is partially open. This is effectively achieved by an engine characterized in that the control valve is configured to have a maximum opening degree when the valve is partially opened.

上記副吸気通路に供給される気体は、好ましくは空気で
あるが、燃料と空気との混合気でもよく、またエンジン
自身の排ガスでもよい。The gas supplied to the sub-intake passage is preferably air, but may be a mixture of fuel and air, or may be exhaust gas from the engine itself.

上記気体が空気であるとき上記気体の供給源は大気であ
り、まだ混合気の場合は気化器付エンジンでは気体供給
源はベンチュリ下流の主吸気通路若しくは吸気マニホル
ドが適当であり、さらに排ガスの場合は排気マニホルド
が適当な気体供給源となる。When the above gas is air, the supply source of the above gas is the atmosphere, and when it is still a mixture, the main intake passage downstream of the venturi or the intake manifold is suitable as the gas supply source for engines with a carburetor, and in the case of exhaust gas. The exhaust manifold is a suitable gas source.

上記本発明に係るエンジンでは、特にアイドリンク時お
よび軽負荷運転時にはスロットル開度が小さいため、ス
ロットル弁の絞り作用が犬で主吸気通路からの吸気流入
速度は緩かで吸気量が少なく吸気行程において燃焼室内
は高負圧となり、気体供給源の気体はこの強力な燃焼室
内負圧に引かれて噴射孔より燃焼室内の設定方向に向か
って噴射され、燃焼室内に強力な渦流あるいは乱流が発
生して燃焼速度が上昇し、希薄燃焼限界が伸長して燃費
が改善され、また、燃焼室内に配置された点火プラグの
火花間隙周辺に上記噴射孔からの噴流が作用すると燃焼
ガスの掃気が行われて着火性が向上するとともに、同掃
気作用によっても希薄燃焼限界が伸長される。In the above-mentioned engine according to the present invention, the throttle opening is small especially during idling and light load operation, so the throttling action of the throttle valve is slow and the intake air inflow speed from the main intake passage is slow, resulting in a small amount of intake air during the intake stroke. In the combustion chamber, there is a high negative pressure, and the gas from the gas supply source is attracted by this strong negative pressure in the combustion chamber and is injected from the injection hole in a set direction inside the combustion chamber, creating a strong vortex or turbulent flow inside the combustion chamber. This increases the combustion speed, extends the lean burn limit, and improves fuel efficiency.Furthermore, when the jet from the injection hole acts around the spark gap of the ignition plug located in the combustion chamber, scavenging of the combustion gas occurs. In addition to improving ignition performance, the scavenging action also extends the lean burn limit.

従って、混合気の分配性が悪く、しかも燃焼室壁温か低
くて燃焼性が悪いアイドリンクあるいは軽負荷運転領域
において希薄混合気燃焼を行っても出力低下および燃費
増大が最小限に押えられ、まだ、空燃比増大により燃焼
最高温度が低下してＮ’Ｏｘの発生量が極度に低械され
る。Therefore, even if lean mixture combustion is performed in the idling or light-load operation ranges where the air-fuel mixture distribution is poor and the combustion chamber wall temperature is low and combustibility is poor, the output loss and increase in fuel consumption can be kept to a minimum, and still As the air-fuel ratio increases, the maximum combustion temperature decreases, and the amount of N'Ox generated is extremely reduced.

また、本発明のエンジンに排ガス還流装置を併用すれば
、制御性の悪い空燃比を燃焼限界に近い高い値に設定し
なくても、容易にＮＯｘの発生量を低滅することが可能
となり、排ガス還流による着火性および火焔伝播速度の
悪化も上記噴流により改善される。Furthermore, if an exhaust gas recirculation device is used in conjunction with the engine of the present invention, the amount of NOx generated can be easily reduced without setting the air-fuel ratio, which is difficult to control, to a high value close to the combustion limit. Deterioration of ignitability and flame propagation velocity due to reflux is also improved by the jet flow.

さらに、本発明のエンジンによれば副吸気通路を介して
供給される気体流量を特に燃費の改善に適した特性に従
って供給することができるものである。Further, according to the engine of the present invention, the gas flow rate supplied through the auxiliary intake passage can be supplied according to characteristics particularly suitable for improving fuel efficiency.

以下、第１図および第２図に従って本発明の１実施例を
説明する。An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

１０は自動車用ガソリン内燃機関の本体、１２はシリン
ダヘッド、１４はシリンダブロック、１６はピストン、
１８は燃焼室、２０は点火プラグ、２２は主吸気ポート
、２４は排気ポート、２６は主吸気弁、２８は吸気マニ
ホルド３０は気化器、３２はエアクリーナである。10 is a main body of an automobile gasoline internal combustion engine, 12 is a cylinder head, 14 is a cylinder block, 16 is a piston,
18 is a combustion chamber, 20 is a spark plug, 22 is a main intake port, 24 is an exhaust port, 26 is a main intake valve, 28 is an intake manifold, 30 is a carburetor, and 32 is an air cleaner.

シリンダヘッド１２には燃焼室１８に開口する噴射孔３
４が穿設され、同噴射孔は点火プラグ２０の火花間隙３
６直下に指向されるとともにピストン１６の頂面と例え
ば３０°〜６０°程度の設定角度を有してピストン１６
方向に指向されている。The cylinder head 12 has an injection hole 3 that opens into the combustion chamber 18.
4 is drilled, and the injection hole is located in the spark gap 3 of the spark plug 20.
The piston 16 is oriented directly below the piston 16 and has a set angle of, for example, about 30° to 60° with the top surface of the piston 16.
oriented in a direction.

まだ、同噴射孔３４は副吸気弁３８を介して副吸気通路
４０に接続されている。The injection hole 34 is still connected to the sub-intake passage 40 via the sub-intake valve 38.

主吸気弁２６および副吸気弁３８は共に同一のロツカア
ーム４２により駆動されるキノコ弁で、同ロツカアーム
はロツカシャフト４４に嵌合され図示しない機関のクラ
ンクシャフトに連動して回動されるカムシャフト４６に
設けられたカム４８に当接して揺動する。The main intake valve 26 and the sub-intake valve 38 are both mushroom valves driven by the same rocker arm 42, and the rocker arm is fitted onto a rocker shaft 44 and rotated by a camshaft 46 in conjunction with a crankshaft of an engine (not shown). It comes into contact with a cam 48 provided on the cam 48 and swings.

また、上記ロツカアーム４２のカム４８への当接面とは
反対側のアーム部は２叉に分岐し、各分岐部にはそれぞ
れアジャストスクリュ５０，５２が螺着され、一方のア
ジャストスクリュ５０端面は主吸気弁２６の弁棒上端面
に当接し、他方のアジャストスクリュ５２端面は副吸気
弁３８の弁棒端面に当接している。Further, the arm portion of the rocker arm 42 on the side opposite to the contact surface with the cam 48 branches into two parts, and adjusting screws 50 and 52 are screwed into each branch part, respectively, and the end face of one adjusting screw 50 is screwed into each branch part. The adjustment screw 52 is in contact with the upper end surface of the valve stem of the main intake valve 26 , and the end surface of the other adjustment screw 52 is in contact with the end surface of the valve stem of the sub-intake valve 38 .

５４は上記排気ポート２４に設けられた排気弁でカム５
６によりロツカアーム５８を介して開閉され排気ガスを
排気マニホルド６０に排出する。54 is an exhaust valve provided in the exhaust port 24 and the cam 5
6 opens and closes via the rocker arm 58 to discharge exhaust gas to the exhaust manifold 60.

エアクリーナ３２より気化器３０および吸気マニホルド
２８を介して吸気ポート２２に連通する主吸気通路６２
の気化器部分にはプライマリポート６４及びセカンダリ
ポート６６が設けられそれぞれベンチュリ６８，７０お
よびスロットル弁７２ ，７４が配置されている。A main intake passage 62 that communicates from the air cleaner 32 to the intake port 22 via the carburetor 30 and the intake manifold 28
A primary port 64 and a secondary port 66 are provided in the carburetor portion, and venturis 68, 70 and throttle valves 72, 74 are disposed, respectively.

上記ベンチュリ６８，７０には主として中高負荷時に燃
料を供給するメインノズル７６，７８が設けられている
。The venturis 68, 70 are provided with main nozzles 76, 78 that supply fuel mainly during medium to high loads.

まだ、上記副吸気通路４０は吸気マニホルド２８に一体
に形成された通路手段８０を介し、プライマリポート６
４のベンチュリ６８より下流側で且つスロットル弁７２
より上流側の主吸気通路６２に常時連通されている。Still, the auxiliary intake passage 40 is connected to the primary port 6 via passage means 80 integrally formed with the intake manifold 28.
4 downstream of the venturi 68 and the throttle valve 72
It is constantly communicated with the main intake passage 62 on the more upstream side.

該副吸気通路４０には絞り８２が設けられて吸気流量が
制限され、該絞り８２をバイパスして制御弁装置８４に
より開閉制御されるとともに絞り８６により吸気流量が
制限されたバイパス通路８８を備えている。The auxiliary intake passage 40 is provided with a throttle 82 to limit the intake flow rate, and includes a bypass passage 88 that bypasses the throttle 82 and is controlled to open and close by a control valve device 84, and in which the intake flow rate is restricted by a throttle 86. ing.

上記制御弁装置８４は、一端がスロットル弁７２全閉時
にはその上流にあり同スロットル弁７２が部分開時には
その下流になる位置９０に連通され他端がダイヤフラム
９２を有した負圧室９４に連通された吸気系負圧通路９
６、同吸気系負圧通路９６を大気開放するサーモバルブ
９８及び上記ダイヤフラム９２に連結された制御弁１０
０を備えている。The control valve device 84 has one end communicating with a position 90 that is upstream of the throttle valve 72 when it is fully closed and downstream of the throttle valve 72 when the throttle valve 72 is partially open, and the other end communicating with a negative pressure chamber 94 having a diaphragm 92. Intake system negative pressure passage 9
6. A thermovalve 98 that opens the negative pressure passage 96 of the intake system to the atmosphere, and a control valve 10 connected to the diaphragm 92.
0.

１０２は上記負圧室９４に内設され上記ダイヤフラム９
２を介して制御弁１００を閉方向に付着するスプリング
である。102 is installed inside the negative pressure chamber 94 and connects the diaphragm 9
2 to attach the control valve 100 in the closing direction.

上記サーモバルブ９８は上記吸気マニホルド２８に設け
られ機関冷却水が導入されるヒートライザ１０４に挿入
された感熱部１０６と、同感熱部１０６に内設されだ熱
膨張性のサーモワックス１０８と、同サーモワックス１
０８の熱膨張により作動されるロツド１１０と、同ロツ
ド１１０の作動により上記吸気系負圧通路９６を大気開
放通路１１２に連通せしめる大気開放弁１１４と、エア
クリーナ１１６とを有している。The thermovalve 98 includes a heat sensitive part 106 inserted into a heat riser 104 provided in the intake manifold 28 and into which engine cooling water is introduced, a thermally expandable thermowax 108 disposed inside the heat sensitive part 106, and a thermowax 108 with thermal expansion property installed inside the heat sensitive part 106. wax 1
08, an air release valve 114 which connects the intake system negative pressure passage 96 to the air release passage 112 by the operation of the rod 110, and an air cleaner 116.

上記構成に従い、機関温態時にはロツド１１０が作動し
てサーモバルプ９８が吸気系負圧通路９６を連通せしめ
るので、制御弁装置８４の負圧室９４にスロットル弁７
２全閉位置直上流の負圧が供給され、該負圧に比例して
副吸気通路４０の開度を得、燃焼室１８の噴射孔３４か
ら気体が噴射される。According to the above configuration, when the engine is in a hot state, the rod 110 operates and the thermovalp 98 communicates with the intake system negative pressure passage 96, so that the throttle valve 7 is connected to the negative pressure chamber 94 of the control valve device 84.
2. Negative pressure immediately upstream of the fully closed position is supplied, the opening of the auxiliary intake passage 40 is obtained in proportion to the negative pressure, and gas is injected from the injection hole 34 of the combustion chamber 18.

一方、エアクリーナ３２から主吸気通路６２に吸入され
た空気の大部分が気化器３０において燃料と所定の空燃
比に混合されて吸気ポート２２から燃焼室１８に吸入さ
れる。On the other hand, most of the air taken into the main intake passage 62 from the air cleaner 32 is mixed with fuel at a predetermined air-fuel ratio in the carburetor 30 and taken into the combustion chamber 18 through the intake port 22.

上記噴射孔３４からの噴射量および噴流の強さはスロッ
トル弁７２の開度すなわち機関の負荷及び副吸気通路４
０に設けられた制御弁１００の開度に応じて変化する。The amount of injection from the injection hole 34 and the strength of the jet flow are determined by the opening of the throttle valve 72, that is, the load of the engine, and the auxiliary intake passage 4.
It changes according to the opening degree of the control valve 100 provided at 0.

即ちスロットル開度が小さいアイドリンク時あるいは軽
負荷時にはスロットル弁７２の絞り作用により主吸気通
路６２から供給される混合気量が少なく、燃焼室１８に
は吸気行程中に高負圧が発生し、スロットル弁７２上流
側の主吸気通路６２は略大気圧であるため、圧力差によ
り副吸気通路４０を介し絞り８２により制限された空気
が噴射孔３４から燃焼室１８内に強力に噴射される。That is, during idling with a small throttle opening or under light load, the amount of air-fuel mixture supplied from the main intake passage 62 is small due to the throttling action of the throttle valve 72, and high negative pressure is generated in the combustion chamber 18 during the intake stroke. Since the main intake passage 62 on the upstream side of the throttle valve 72 is at approximately atmospheric pressure, air restricted by the throttle 82 is powerfully injected into the combustion chamber 18 from the injection hole 34 via the auxiliary intake passage 40 due to the pressure difference.

この結果燃焼室１８内の吸入混合気は上記空気の噴出流
により強い渦流あるいは乱流を生じるとともに空気の混
合により主吸気通路６２から吸入された混合気は層状化
され、または不均質な斑状態で希釈される。As a result, the air-fuel mixture sucked into the combustion chamber 18 generates a strong vortex or turbulence due to the air jet flow, and the air-fuel mixture sucked from the main intake passage 62 becomes stratified or unevenly formed due to the mixing of the air. diluted with

また、上記噴出流は点火プラグ２０の火花間隙３６近く
を通過するため、火花間隙３６付近の残留燃焼ガスも誘
動されて掃気され、同火花間隙付近に新しい吸入混合ガ
スが流入する。Furthermore, since the jet flow passes near the spark gap 36 of the spark plug 20, residual combustion gas near the spark gap 36 is also induced and scavenged, and new intake mixed gas flows into the vicinity of the spark gap.

従って、圧縮行程の後半期に行われる点火時においても
、空気と混合気が層状または斑状に分布しだ状態で強い
渦流あるいは乱流が存在しておりまた、火花間隙３６付
近には常に吸入混合気が流動しているものと考えられ、
実験によれば従来の機関に比較して火焔伝播速度が向上
して失火限界が飛躍的に拡張され、燃費が改善されると
ともに混合気を希薄化した場合でも出力低下が少なくド
ライバビリテイが向上することを確認し得た。Therefore, even at the time of ignition, which occurs in the latter half of the compression stroke, there is a strong vortex or turbulence in which the air and mixture begin to be distributed in layers or in patches, and the suction mixture is always present near the spark gap 36. It is thought that the air is flowing,
Experiments have shown that compared to conventional engines, the flame propagation speed has been improved, the misfire limit has been dramatically expanded, fuel efficiency has been improved, and even when the mixture is lean, there is less output loss and drivability has been improved. I was able to confirm that.

次にスロットル開度が中程度の中負荷運転領域において
は、スロットル弁７２により絞り効果が中程度で、副吸
気通路４０と主吸気通路６２との差圧がやや小さくなる
が、上記制御弁装置８４の制御弁１００がスロットル弁
７２全閉位置の位置９０の負圧に応じて最大開度となる
ので、絞り８２及びバイパス通路８８の絞り８６を介し
て制限された比較的多量の空気が供給、噴射され、差圧
の械少を充分に補償する。Next, in a medium load operating region where the throttle opening is medium, the throttling effect by the throttle valve 72 is medium and the differential pressure between the auxiliary intake passage 40 and the main intake passage 62 is slightly small. Since the control valve 100 of 84 reaches its maximum opening depending on the negative pressure at position 90 when the throttle valve 72 is fully closed, a relatively large amount of restricted air is supplied through the throttle 82 and the throttle 86 of the bypass passage 88. , is injected and fully compensates for the mechanical loss of differential pressure.

′一方、スロットル開度が大きい高負荷運転領域におい
ては、スロットル弁７２による絞９作用が小さく、主吸
気通路６２を介して多量の混合気が燃焼室１８内に吸入
されるため、又、制御弁１００が実線図示の如くバイパ
ス通路８８を閉塞するので、副吸気通路４０からの噴射
量および噴出力は絞り８２のみを介して行なわれるだめ
低下して噴射空気のスワール効果も滅少するが、この場
合には吸気効率が犬で、しかも混合気が吸気ポート２２
より燃焼室１８に流入する時強力な渦流あるいは乱流を
生じ、まだ燃焼室１８の内壁の温度も上昇するため、特
に噴射孔３４からの噴流により強い渦流や乱流を発生さ
せなくても火焔伝播速度が高く燃焼性は良好である。'On the other hand, in a high-load operating region with a large throttle opening, the throttling action by the throttle valve 72 is small, and a large amount of air-fuel mixture is sucked into the combustion chamber 18 through the main intake passage 62. Since the valve 100 closes the bypass passage 88 as shown by the solid line, the injection amount and injection force from the sub-intake passage 40 are reduced because they are performed only through the throttle 82, and the swirl effect of the injection air is also reduced. In this case, the intake efficiency is low, and the air-fuel mixture is at the intake port 22.
When the jet flows into the combustion chamber 18, a strong vortex or turbulent flow is generated, and the temperature of the inner wall of the combustion chamber 18 still rises. The propagation velocity is high and the flammability is good.

又、機関冷却時には第２図実線で示す如くサーモバルブ
９８が吸気系負圧通路９６を大気開放せしめるので、制
御弁装置８４はスプリング１０２の付勢力により制御弁
１００がバイパス通路８８を閉塞する。Furthermore, during engine cooling, the thermovalve 98 opens the intake system negative pressure passage 96 to the atmosphere as shown by the solid line in FIG.

特に該機関冷態始動時には燃焼室１８内の燃焼が極めて
不安定であり、且つ燃焼限界最犬空燃比が著しく低下す
るが、この時には上記燃焼室１８には主吸気通路６２及
び副吸気通路４０の絞り８２のみを介して気化器３０の
形成した混合気及び制限された副空気が供給され、該制
限された噴射空気により空燃比が過大とならず、従って
冷態時においても安定した燃焼が行なえる。Particularly when the engine is started in a cold state, the combustion within the combustion chamber 18 is extremely unstable, and the maximum air-fuel ratio at the flammability limit is significantly reduced. The air-fuel mixture formed by the carburetor 30 and limited auxiliary air are supplied only through the throttle 82 of the carburetor 30, and the limited injection air prevents the air-fuel ratio from becoming excessive, thus ensuring stable combustion even in cold conditions. I can do it.

以上より明らかなごとく、本実施例によれば、燃焼室１
８の内壁温度が比較的低く、吸入効率が悪い等の燃焼条
件の悪い軽負荷運転領域において、燃焼室１８内で噴射
孔３４より流入する空気を混合して得られた総合空燃比
が１１〜１４程度の混合気は勿論のこと、総合空燃比が
１５〜２１程度の希薄混合気若しくは排気ガス還流を行
なって得られる燃焼性の悪い混合気でも安定的に燃焼さ
せることができ、この際噴射孔３４からの強力な空気噴
射により強い渦流まだは乱流が発生するとともに、噴射
された空気が主吸気通路６２から吸入された混合気に適
度な層状まだは斑状態で混合されることにより、ＮＯｘ
の発生量が増大することなく燃焼速度が向上して燃焼完
了時間が短縮され燃費が低滅されるとともにドライバビ
リテイが向上し、しかもＨＣ ，ＣＯ等の未燃焼ガスの
排出量も低械されるという効果を奏する。As is clear from the above, according to this embodiment, the combustion chamber 1
In a light load operation region with poor combustion conditions such as relatively low inner wall temperature of the combustion chamber 18 and poor intake efficiency, the total air-fuel ratio obtained by mixing the air flowing in from the injection holes 34 in the combustion chamber 18 is 11 to 12. It is possible to stably combust not only a mixture with a total air-fuel ratio of about 14, but also a lean mixture with a total air-fuel ratio of about 15 to 21, or a mixture with poor combustibility obtained by exhaust gas recirculation. The strong air injection from the hole 34 generates a strong vortex or turbulent flow, and the injected air is mixed with the air-fuel mixture taken in from the main intake passage 62 in an appropriate stratified or patchy state. NOx
The combustion speed is improved without increasing the amount of HC, CO, and other unburned gas emissions, and the combustion completion time is shortened, resulting in lower fuel consumption and improved drivability. It has the effect of

又、副吸気通路４０に供給される空気量は絞り８２及び
絞り８６の径をそれぞれ単独に適宜設定し，得るので、
運転条件に応じた適切な噴射空気量を得る等の効果を奏
する。Furthermore, the amount of air supplied to the sub-intake passage 40 can be obtained by appropriately setting the diameters of the throttle 82 and the throttle 86, respectively.
This provides effects such as obtaining an appropriate amount of injection air depending on the operating conditions.

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

第１図は本発明の一実施例を示す概略説明図、第２図は
第１図における■−■矢視断面図である。 １０・・・・・・エンシン本体、１２・・・・・・シリ
ンダヘッド、１４・・・・・・シリンダブロック、１８
・・・・・・燃焼室、２０・・・・・・点火プラグ、２
２・・・・・・主吸気ポート、２６・・・・・・主吸気
弁、３０・・・・・・気化器、３４・・・・・・噴射孔
、３６・・・・・・火花間隙、３８・・・・・・副吸気
弁、４０・・・・・・副吸気通路、５４・・・・・・排
気弁、６０・・・・・・排気マニホルド、６２・・・・
・・主吸気通路、８２，８６・・・・・・絞り、８４・
・・・・・制御弁装置、８８・・・・・・バイパス通路
、９８・・・・・・サーモバルブ、１００・・・・・・
制御弁。FIG. 1 is a schematic explanatory diagram showing one embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line -■ in FIG. 10...Engine body, 12...Cylinder head, 14...Cylinder block, 18
... Combustion chamber, 20 ... Spark plug, 2
2...Main intake port, 26...Main intake valve, 30...Carburizer, 34...Injection hole, 36...Spark Gap, 38...Sub-intake valve, 40...Sub-intake passage, 54...Exhaust valve, 60...Exhaust manifold, 62...
...Main intake passage, 82, 86... Throttle, 84.
... Control valve device, 88 ... Bypass passage, 98 ... Thermo valve, 100 ...
control valve.

Claims (1)

【特許請求の範囲】[Claims] １ 燃焼室内に点火プラグのスパークギャップを臨ませ
るとともに、同スパークギャップの近傍に上記燃焼室の
設定方向に指向して空気、混合気、排気ガス等の気体を
噴射する噴射孔を設けたエンジンにおいて、上記燃焼室
に主吸気弁を介して吸気を供給する主吸気通路、同主吸
気通路に設けられ吸気流量を制御する絞り弁、上記噴射
孔に常時連通するとともに上記主吸気通路とは別個に設
けられ絞りを介して吸気流量が制限される副吸気通路、
同副吸気通路と並列に設けられ絞りを介して吸気流量が
制限されるバイパス通路及び同バイパス通路を開閉する
制御弁を備え、上記制御弁は上記主吸気通路に設けられ
た絞り弁が全閉時にはその上流にあり同絞り弁が部分開
時にはその下流になる位置の負圧に応じて開閉され、上
記絞り弁が部分開時に上記制御弁が最大開度となるよう
に構成されたことを特徴とするエンジン。1. In an engine that has a spark gap of a spark plug facing into the combustion chamber, and has an injection hole near the spark gap that injects gas such as air, air-fuel mixture, exhaust gas, etc. in the direction in which the combustion chamber is set. , a main intake passage that supplies intake air to the combustion chamber via the main intake valve, a throttle valve provided in the main intake passage to control the intake air flow rate, and a throttle valve that is always in communication with the injection hole and separate from the main intake passage. a sub-intake passage in which the intake flow rate is restricted through a throttle;
A bypass passage is provided in parallel with the auxiliary intake passage and the intake flow rate is restricted via a throttle, and a control valve is provided to open and close the bypass passage, and the control valve is configured so that the throttle valve provided in the main intake passage is fully closed. Sometimes, the throttle valve is located upstream of the throttle valve, and when the throttle valve is partially open, the control valve is opened and closed in response to negative pressure at a downstream position, and when the throttle valve is partially open, the control valve is opened to the maximum degree. engine.