JP3395583B2 - Fuel control system for in-cylinder injection spark ignition internal combustion engine - Google Patents
Fuel control system for in-cylinder injection spark ignition internal combustion engineInfo
- Publication number
- JP3395583B2 JP3395583B2 JP17594497A JP17594497A JP3395583B2 JP 3395583 B2 JP3395583 B2 JP 3395583B2 JP 17594497 A JP17594497 A JP 17594497A JP 17594497 A JP17594497 A JP 17594497A JP 3395583 B2 JP3395583 B2 JP 3395583B2
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- combustion
- fuel
- injection
- residual amount
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
Landscapes
- Exhaust-Gas Circulating Devices (AREA)
- Fuel-Injection Apparatus (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は筒内直接燃料噴射式
の火花点火内燃機関の改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a direct fuel injection type spark ignition internal combustion engine.
【０００２】[0002]
【従来の技術】従来、特開平５−７９３３７号公報にも
あるように、圧縮行程の後半で燃料を直接的に気筒内に
噴射し、点火時に点火栓の近傍に可燃混合気層を形成
し、いわゆる成層燃焼により、全体的には超希薄混合気
でありながら、安定した燃焼を行い、燃費や排気組成を
大幅に改善した内燃機関が知られている。2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Laid-Open No. 5-79337, fuel is directly injected into a cylinder in the latter half of a compression stroke to form a combustible mixture layer near the spark plug during ignition. There is known an internal combustion engine in which stable combustion is achieved by so-called stratified combustion, while it is an ultra-lean mixture as a whole, and fuel consumption and exhaust gas composition are significantly improved.
【０００３】この内燃機関にあっては、機関の高負荷時
など高出力を発生させるため、燃料の噴射時期を吸気行
程に移し、燃料と空気を予め混合しておき、理論空燃比
付近での均質燃焼を行うようになっている。In this internal combustion engine, in order to generate a high output, such as when the engine is under heavy load, the fuel injection timing is shifted to the intake stroke, the fuel and air are mixed in advance, and the fuel is injected near the stoichiometric air-fuel ratio. It is designed to perform homogeneous combustion.
【０００４】この場合、成層燃焼から均質燃焼に切換え
るとき、成層燃焼からいきなり理論空燃比での均質燃焼
に移行させるのではなく、成層燃焼よりは空燃比として
は濃いが希薄混合気を用いての均質希薄燃焼領域を間に
介在させ、出力トルクに急激な段差が発生しないように
している。In this case, when the stratified combustion is switched to the homogeneous combustion, the stratified combustion is not suddenly changed to the homogeneous combustion at the stoichiometric air-fuel ratio, but a lean air-fuel mixture which is richer in air-fuel ratio than the stratified combustion is used. A homogeneous lean burn region is interposed to prevent a sudden step in output torque.
【０００５】この均質希薄燃焼への切換中は、燃料の噴
射時期を吸気行程と圧縮行程に分け、その噴射量の分担
比率を機関負荷に応じて変化させ、切換時の燃焼安定性
を保っている。During the switching to the homogeneous lean combustion, the fuel injection timing is divided into the intake stroke and the compression stroke, and the sharing ratio of the injection amount is changed according to the engine load to maintain the combustion stability during the switching. There is.
【０００６】[0006]
【発明が解決しようとする課題】ところで、成層燃焼中
は超希薄混合気による燃焼のため燃焼時に発生するＮＯ
ｘの絶対量は少ないが、三元触媒によりＮＯｘを還元で
きないため、発生量そのものを減少させるべく排気還流
を行っている。By the way, during stratified combustion, NO generated during combustion due to combustion with an ultra-lean air-fuel mixture.
Although the absolute amount of x is small, NOx cannot be reduced by the three-way catalyst, so exhaust gas recirculation is performed to reduce the amount itself.
【０００７】成層燃焼時には点火栓の近傍にのみ可燃混
合気層を形成するので、比較的大量の排気還流を行って
も、燃焼の安定性が損なわれることはないが、成層燃焼
ではない均質希薄燃焼時には、燃料と空気は予混合状態
にあるため、排気還流による燃焼への影響が大きく、燃
焼の安定性が悪化する。Since a combustible air-fuel mixture layer is formed only near the spark plug during stratified charge combustion, even if a relatively large amount of exhaust gas recirculation is carried out, the stability of combustion is not impaired, but it is not a stratified charge homogeneous dilution. At the time of combustion, the fuel and air are in a premixed state, so the exhaust gas recirculation has a large effect on combustion and the stability of combustion deteriorates.
【０００８】そのため、均質希薄燃焼時には排気還流を
停止しているが、この停止時に排気還流制御弁を全閉に
しても、直ちに排気還流が遮断されるわけではなく、吸
気系に残存する還流排気があり、このため切換途中にお
いて残留排気の影響で燃焼が不安定化しやすいという問
題があった。Therefore, the exhaust gas recirculation is stopped at the time of homogeneous lean combustion, but even if the exhaust gas recirculation control valve is fully closed at the time of this stop, the exhaust gas recirculation is not immediately interrupted, and the recirculated exhaust gas remaining in the intake system. Therefore, there is a problem that combustion tends to become unstable due to the influence of residual exhaust gas during the switching.
【０００９】燃焼の安定性を改善するのに、切換中にお
ける燃料の２回噴射はそれなりの効果はあるものの、従
来のように、切換時の機関負荷に応じてのみ燃料噴射の
分担率を調整し、とくに吸気行程での噴射量の分担率を
大きくしているものでは、混合気の均質化（予混合化）
の度合いが高く、この場合には残留排気による燃焼の悪
化が避けられない。In order to improve the stability of combustion, the double injection of fuel during the switching has some effect, but as in the conventional case, the fuel injection sharing rate is adjusted only according to the engine load at the time of switching. However, especially in the case where the share of the injection amount in the intake stroke is large, homogenization of the air-fuel mixture (premixing)
Is high, and in this case, deterioration of combustion due to residual exhaust is unavoidable.
【００１０】本発明は、成層燃焼から吸気行程と圧縮行
程との２回に分けて燃料噴射を行う希薄燃焼への切換時
に、吸気系に残留する排気量に対応して吸気行程での燃
料噴射担率を制限し、燃焼安定性を向上させることを目
的とする。According to the present invention, when the stratified combustion is switched to the lean combustion in which the fuel injection is divided into the intake stroke and the compression stroke, the fuel injection in the intake stroke is performed corresponding to the amount of exhaust gas remaining in the intake system. The purpose is to limit the share and improve the combustion stability.
【００１１】[0011]
【課題を解決するための手段】第１の発明は、気筒内に
直接燃料を噴射し、この燃料の噴射時期を圧縮行程に設
定することで成層燃焼を行い、吸気行程に設定すること
で均質燃焼を行うと共に、成層燃焼から均質燃焼への切
換時には吸気行程と圧縮行程の２回に分けて燃料を噴射
して希薄燃焼を行う筒内直接噴射式火花点火内燃機関に
おいて、排気の一部を吸気中に還流する排気還流手段
と、この排気還流を成層燃焼から前記希薄燃焼への切換
に伴い遮断する手段と、排気還流の遮断時に吸気系に残
存する還流排気の残留量を計測する手段と、前記希薄燃
焼での吸気行程と圧縮行程での燃料噴射の分担率を前記
還流排気の残留量に応じて補正する手段とを備える。SUMMARY OF THE INVENTION The first aspect of the present invention is injected <br/> straight Se' charge into the cylinder, subjected to stratified combustion by setting the injection timing of the fuel in the compression stroke, the intake stroke In the direct injection spark ignition internal combustion engine for in-cylinder injection, which performs lean combustion by injecting fuel in two steps of intake stroke and compression stroke when switching from stratified combustion to homogeneous combustion, and exhaust gas recirculation means for recirculating a part of exhaust during the intake, and means for blocking with the exhaust gas recirculation in switching to the lean combustion from the stratified combustion, the residual of the recirculated exhaust gas remaining in the intake system at the time of interruption of the exhaust gas recirculation and means for measuring the amount, and means for correcting the distribution ratio of the fuel injection in the intake stroke and the compression stroke in the lean combustion to the residual amount of the <br/> recirculated exhaust gas.
【００１２】第２の発明は、第１の発明において、前記
補正手段は吸気行程よりも圧縮行程での燃料噴射の分担
率の大きい領域を還流排気の残留量に応じて変化させ
る。According to a second aspect of the present invention, in the first aspect, the correcting means changes a region in which the fuel injection share is higher in the compression stroke than in the intake stroke, depending on the residual amount of the recirculated exhaust gas.
【００１３】第３の発明は、第１または第２の発明にお
いて、前記補正手段は吸気行程よりも圧縮行程での燃料
噴射の分担率が大きい領域をそのときの空燃比に応じて
変化させる。According to a third aspect of the present invention, in the first or second aspect, the correcting means changes a region in which the share of fuel injection in the compression stroke is larger than that in the intake stroke, in accordance with the air-fuel ratio at that time.
【００１４】第４の発明は、第１〜第３の発明におて、
前記残留量計測手段は還流排気の残留量を還流排気遮断
時の吸入空気量に応じて推定する。The fourth invention is based on the first to third inventions.
The residual amount measuring means estimates the residual amount of the recirculated exhaust gas according to the intake air amount when the recirculated exhaust gas is shut off.
【００１５】第５の発明は、第４の発明において、前記
残留量計測手段は還流排気遮断時の推定残留量を基にし
てエンジン回転数と負荷に応じて所定の時間毎の残留量
を推定する。In a fifth aspect based on the fourth aspect, the residual amount measuring means estimates the residual amount at predetermined time intervals according to the engine speed and the load based on the estimated residual amount when the recirculation exhaust gas is cut off. To do.
【００１６】[0016]
【発明の作用・効果】第１の発明において、成層燃焼か
ら均質燃焼への移行過程で、燃料の噴射が２回に分割さ
れる希薄燃焼域に入るが、このとき排気還流が停止され
ても、しばらくは還流排気の一部が吸気系に残留する。
しかし、この希薄燃焼域では、燃料が吸気行程で噴射さ
れる割合よりも、圧縮行程で噴射される割合の方が大き
くなるようにその分担率が補正され、このため、残留量
の大きい切換初期にあっては、吸気行程で噴射された拡
散燃料を一部に含むものの、圧縮行程で噴射された燃料
により点火栓近傍に可燃混合気層が維持され、成層燃焼
する。このため還流排気が残留しても安定した燃焼特性
が維持され、良好な運転特性が保てる。In the first aspect of the invention, in the transition process from the stratified charge combustion to the homogeneous charge combustion, the fuel injection enters into the lean burn region where the fuel injection is divided into two, but even if the exhaust gas recirculation is stopped at this time. , A part of the recirculated exhaust gas remains in the intake system for a while.
However, in this lean burn region, the share rate is corrected so that the proportion of fuel injected in the compression stroke is greater than the proportion of fuel injected in the intake stroke. In this case, although the diffused fuel injected in the intake stroke is included in part, the combustible mixture layer is maintained near the spark plug by the fuel injected in the compression stroke, and stratified charge combustion is performed. Therefore, even if the recirculated exhaust gas remains, stable combustion characteristics are maintained and good operation characteristics can be maintained.
【００１７】第２の発明では、還流排気の残留量が多い
ときほど圧縮行程での分担率が高まり、実質的な成層燃
焼により、燃焼の悪化を確実に防止できる。In the second aspect of the invention, the larger the residual amount of the recirculated exhaust gas is, the higher the share of the compression stroke is, and the deterioration of the combustion can be surely prevented by the substantially stratified combustion.
【００１８】第３の発明では、燃料噴射の分担率は、そ
の運転状態によって決まる空燃比（当量比）に対応し、
空燃比の小さい領域ほど圧縮行程での分担率を高め、燃
焼安定性を向上させられる。In the third aspect of the invention, the share of fuel injection corresponds to the air-fuel ratio (equivalent ratio) determined by the operating state,
The smaller the air-fuel ratio, the higher the share in the compression stroke and the higher the combustion stability.
【００１９】第４の発明では、還流排気の残留量が切換
時の吸入空気量に依存し、したがってこれに応じて燃料
分担率を補正することで、高い燃焼安定性を保つことが
できる。In the fourth aspect of the invention, the residual amount of the recirculated exhaust gas depends on the intake air amount at the time of switching. Therefore, by correcting the fuel sharing ratio accordingly, high combustion stability can be maintained.
【００２０】第５の発明では、切換後の時間経過に伴う
還流排気の残留量が把握され、これに応じて燃料分担率
を補正することで、実際の残留量に対応して燃焼安定性
を高められる。In the fifth aspect of the invention, the residual amount of the recirculated exhaust gas is grasped with the lapse of time after the switching, and the fuel sharing rate is corrected accordingly, so that the combustion stability can be improved corresponding to the actual residual amount. To be enhanced.
【００２１】[0021]
【実施の形態】以下本発明の最良の実施の形態を図に基
づいて説明する。BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below with reference to the drawings.
【００２２】図１、図２は全体構成を示すものであり、
１はエンジン本体、２は吸気通路、３は排気通路であ
る。ピストン４の頂面にはキャビティ５が形成され、こ
のキャビティ５に向けて燃料噴射弁６から燃料が直接的
に噴射される。点火栓８を設けた燃焼室７には吸気バル
ブ９を介して吸気通路２からの吸気が導入され、燃焼ガ
スが排気バルブ１０を介して排気通路３へと流れる。な
お、吸気バルブ９と排気バルブ１０は各気筒についてそ
れぞれ２つづつ配置される。FIG. 1 and FIG. 2 show the entire structure,
Reference numeral 1 is an engine body, 2 is an intake passage, and 3 is an exhaust passage. A cavity 5 is formed on the top surface of the piston 4, and fuel is directly injected from the fuel injection valve 6 toward the cavity 5. Intake air from the intake passage 2 is introduced into the combustion chamber 7 provided with the spark plug 8 through the intake valve 9, and combustion gas flows into the exhaust passage 3 through the exhaust valve 10. Two intake valves 9 and two exhaust valves 10 are arranged for each cylinder.
【００２３】吸気通路２の各ブランチにはスワールコン
トロールバルブ１１が配設され、後述する成層燃焼時に
一方の吸気バルブ９から吸気を導入し、燃焼室内にスワ
ールを生起する。A swirl control valve 11 is provided in each branch of the intake passage 2, and intake air is introduced from one intake valve 9 at the time of stratified combustion described later to generate swirl in the combustion chamber.
【００２４】排気通路３から排気の一部を取出して吸気
通路２に還流するため、排気還流通路１３が設けられ、
スロットルバルブ１４の下流に接続する。排気還流通路
１３には排気還流制御弁１５が設けられ、コンロールユ
ニット２０からの制御信号に応じて運転状態に応じて排
気還流を制御する。１６は触媒である。An exhaust gas recirculation passage 13 is provided to take out a part of the exhaust gas from the exhaust passage 3 and recirculate it to the intake passage 2.
It is connected downstream of the throttle valve 14. An exhaust gas recirculation control valve 15 is provided in the exhaust gas recirculation passage 13, and controls the exhaust gas recirculation according to the operating state according to the control signal from the control unit 20. 16 is a catalyst.
【００２５】コンロールユニット２０は前記燃料噴射弁
６の燃料噴射を制御し、また排気還流制御弁１５と共に
スワールコントロールバルブ１１の開度も制御する。The control unit 20 controls the fuel injection of the fuel injection valve 6, and also controls the opening degree of the swirl control valve 11 together with the exhaust gas recirculation control valve 15.
【００２６】このため、コンロールユニット２０には、
エアフローメータ２１からの吸入空気量信号、アクセル
開度センサ２２からのアクセル開度信号、クランク角セ
ンサ２３からの回転数信号、スロットル開度センサ２４
からのスロットルバルブ開度信号などが入力し、これら
に基づいて上記した各制御を実行する。Therefore, the control unit 20 includes
An intake air amount signal from the air flow meter 21, an accelerator opening signal from the accelerator opening sensor 22, a rotation speed signal from the crank angle sensor 23, and a throttle opening sensor 24.
The throttle valve opening signal and the like are input, and the above-described control is executed based on these signals.
【００２７】ここで、この制御内容の概略を説明する
と、前記燃料噴射弁６は、図３にもあるとおり、機関低
負荷域などにおいて燃料を圧縮行程の後半に噴射し、こ
れにより圧縮上死点付近において、点火栓８の近傍のキ
ャビティ５に可燃混合気層を形成し、点火栓８による点
火に伴い燃料を成層燃焼させ、全体としてはＡ／Ｆ＝４
０を越える空燃比による超希薄燃焼を行う。また、機関
の高負荷域では燃料を吸気行程で噴射し、燃料と空気の
混合を早め、燃焼室７の全域を均質的な混合気で満た
し、理論空燃比付近の混合気による均質燃焼を行う。さ
らに成層燃焼域と均質燃焼域との間の中間負荷域におい
て、成層燃焼よりも空燃比としては濃いが、理論空燃比
よりは薄い希薄燃焼を行い、この希薄燃焼時には吸気行
程と圧縮行程の２回に分けて燃料を噴射する。Here, the outline of the control contents will be explained. As shown in FIG. 3, the fuel injection valve 6 injects fuel in the latter half of the compression stroke in the engine low load region, etc., thereby causing compression top dead. Near the point, a combustible mixture layer is formed in the cavity 5 near the spark plug 8, and the fuel is stratified and burned with ignition by the spark plug 8, and A / F = 4 as a whole.
Ultra lean combustion with an air-fuel ratio exceeding 0 is performed. In addition, in the high load region of the engine, fuel is injected in the intake stroke to accelerate the mixing of fuel and air, fill the entire combustion chamber 7 with a homogeneous air-fuel mixture, and perform homogeneous combustion with an air-fuel mixture near the stoichiometric air-fuel ratio. . Further, in an intermediate load region between the stratified combustion region and the homogeneous combustion region, lean combustion is performed, which is richer in air-fuel ratio than stratified combustion but thinner than the stoichiometric air-fuel ratio, and during the lean combustion, two intake strokes and compression strokes are performed. Fuel is injected in divided times.
【００２８】一方、排気還流は成層燃焼域と理論空燃比
での均質燃焼域で行い、そのときの排気還流率は成層燃
焼域の方が均質燃焼域よりも大きく設定され、さらに中
間の希薄燃焼域では燃焼の不安定化を防止するため排気
還流は停止される。On the other hand, the exhaust gas recirculation is performed in the stratified combustion region and the homogeneous combustion region at the stoichiometric air-fuel ratio, and the exhaust gas recirculation rate at that time is set to be larger in the stratified combustion region than in the homogeneous combustion region, and further in the middle lean combustion region. In the region, exhaust gas recirculation is stopped to prevent destabilization of combustion.
【００２９】本実施形態では、成層燃焼から希薄燃焼へ
と切換える際に、排気還流が遮断されるにもかかわら
ず、吸気中に残留する還流排気により、希薄燃焼の安定
性が損なわれるのを防止するために、吸気行程と圧縮行
程の２回に分けて噴射する燃料の噴射割合を残留排気量
に応じて制御するようになっている。In this embodiment, when the stratified charge combustion is switched to the lean burn, the stability of the lean burn is prevented from being impaired by the recirculated exhaust gas remaining in the intake air even though the exhaust gas recirculation is interrupted. In order to do so, the injection ratio of the fuel injected in two times, the intake stroke and the compression stroke, is controlled according to the residual exhaust gas amount.
【００３０】原則的には還流排気の残留があるときは、
実質的に混合気の成層化をはかり、残留排気による燃焼
の悪化を阻止する。圧縮行程でのみ燃料噴射を行う通常
の成層燃焼では、中間負荷域での希薄燃焼時の空燃比は
濃すぎ、点火栓８の近傍では過剰に濃い空燃比により、
かえって燃焼が悪化する。そこで、一部の燃料を吸気行
程で噴射して燃料を拡散しておき、ここに圧縮行程の後
半で適量の燃料を噴射することにより、点火栓近傍の空
燃比がほどよく可燃混合気層を形成するようし、全体と
しては超希薄混合気と理論混合気との中間の希薄混合気
についても、安定して燃焼させるようにしている。In principle, when there is a residue of the reflux exhaust gas,
Substantially stratifies the air-fuel mixture and prevents deterioration of combustion due to residual exhaust. In normal stratified combustion in which fuel injection is performed only in the compression stroke, the air-fuel ratio at the time of lean combustion in the intermediate load region is too rich, and in the vicinity of the spark plug 8 due to the excessively rich air-fuel ratio,
On the contrary, the combustion deteriorates. Therefore, by injecting a part of the fuel in the intake stroke to diffuse the fuel and injecting an appropriate amount of the fuel into the latter half of the compression stroke, the air-fuel ratio near the spark plug is made moderate and the combustible mixture layer is formed. As a whole, even the lean mixture in the middle of the ultra-lean mixture and the theoretical mixture is burned stably.
【００３１】以上の制御内容について、図４のフローチ
ャートにしたがってさらに詳しく説明する。The above control contents will be described in more detail with reference to the flowchart of FIG.
【００３２】ステップ１で運転状態を代表する信号、ア
クセル開度、エンジン回転数などを読み込み、これらに
基づいてステップ２で成層燃焼から均質燃焼への切換制
御（当量比対応制御）が許可されているかどうか判断す
る。図３、図９にも示すように、運転状態に応じて要求
される当量比（空気過剰率の逆数で、当量比が１よりも
大きいときは理論空燃比よりも濃いし、小さいときは薄
くなる）が変わり、この当量比に応じて成層燃焼、均質
希薄燃焼、均質燃焼が切換わる。In step 1, a signal representative of the operating state, accelerator opening, engine speed, etc. are read, and based on these, switching control from stratified combustion to homogeneous combustion (equivalent ratio correspondence control) is permitted. Judge whether there is. As shown in FIG. 3 and FIG. 9, the equivalence ratio (reciprocal of the excess air ratio, which is required depending on the operating state, is darker than the theoretical air-fuel ratio when the equivalence ratio is greater than 1, and is thin when the equivalence ratio is smaller. Is changed, and stratified combustion, homogeneous lean combustion, and homogeneous combustion are switched according to this equivalence ratio.
【００３３】成層燃焼から均質燃焼（希薄燃焼）への許
可が判断されると、ステップ３ではアクセル開度などに
基づいて要求トルクを、またステップ４では目標空気量
と当量比をそれぞれ算出する。ステップ５ではそのとき
の実際の空気量と当量比とを求める。When it is determined that the stratified combustion is permitted to the homogeneous combustion (lean combustion), the required torque is calculated based on the accelerator opening degree in step 3, and the target air amount and the equivalence ratio are calculated in step 4. In step 5, the actual air amount and the equivalence ratio at that time are obtained.
【００３４】ステップ６で成層燃焼と均質燃焼との切換
制御が終了したかどうか判断し、終了していないときは
ステップ７に移行する。In step 6, it is judged whether or not the switching control between the stratified combustion and the homogeneous combustion is completed, and if it is not completed, the routine proceeds to step 7.
【００３５】なお、切換終了の判断はそのときの当量比
に基づいて決まり、当量比が完全に均質燃焼の当量比に
なるまでの間は希薄燃焼を行う。The determination of the end of switching is determined based on the equivalence ratio at that time, and lean combustion is performed until the equivalence ratio reaches the equivalence ratio of homogeneous combustion.
【００３６】したがってステップ７では、そのときの当
量比に基づいて、燃料噴射を２回に分けて行うことが許
可されているかどうかを判断する。つまり、アクセル開
度などに応じて要求される空燃比（当量比）が変化し、
負荷が増大すると、要求空燃比が濃くなっていき、成層
燃焼から均質燃焼へと移行するが、この過程の中間負荷
域での空燃比では燃料噴射が２回に分けられ、希薄燃焼
を行う。Therefore, in step 7, it is judged based on the equivalence ratio at that time whether or not the fuel injection is permitted to be performed in two times. In other words, the required air-fuel ratio (equivalent ratio) changes according to the accelerator opening, etc.
When the load increases, the required air-fuel ratio becomes thicker, and the stratified combustion shifts to the homogeneous combustion, but at the air-fuel ratio in the intermediate load region of this process, the fuel injection is divided into two, and lean combustion is performed.
【００３７】２回噴射が許可されているときは、ステッ
プ８に進み、還流排気の残留量を演算により求める。つ
まり、成層燃焼から均質燃焼への切換が許可された時点
において排気還流が停止されるが、吸気系には残留排気
が存在し、これが時間遅れをもって燃焼室７に吸入され
ていく。なお、排気還流は当量比が理論空燃比での均質
燃焼に入ると再び再開される。When the double injection is permitted, the routine proceeds to step 8 and the residual amount of the recirculated exhaust gas is calculated. That is, the exhaust gas recirculation is stopped when the switching from the stratified combustion to the homogeneous combustion is permitted, but the residual exhaust gas exists in the intake system and is sucked into the combustion chamber 7 with a time delay. The exhaust gas recirculation is restarted when the equivalence ratio enters homogeneous combustion with the stoichiometric air-fuel ratio.
【００３８】還流排気の残留量は、図５に示すようにし
て求められる。The residual amount of the recirculated exhaust gas is obtained as shown in FIG.
【００３９】まず、ステップ１で最初に燃料の２回噴射
が判定されたときの吸入空気量を検出し、ステップ２で
この吸入空気量に基づいて、図６のようなマップから、
排気の残留量を求める。この場合、最初の残留量はその
ときの吸入空気量にほぼ比例し、吸入空気量が小さいと
きほど大きくなる。First, in step 1, the intake air amount at the time when the fuel injection is first judged is detected, and in step 2, based on this intake air amount, from the map as shown in FIG.
Calculate the residual amount of exhaust gas. In this case, the initial residual amount is almost proportional to the intake air amount at that time, and becomes larger as the intake air amount is smaller.
【００４０】また、還流排気の残留量は図７のようにし
て求めることもできる。The residual amount of the recirculated exhaust gas can also be obtained as shown in FIG.
【００４１】この場合、ステップ１と２では、図５と同
じようにして、最初に２回噴射が判定されたときの吸入
空気量から残留する排気還流量求め、ステップ３でエン
ジン回転数とスロットル開度を読み込み、ステップ４で
は、図８に示すようなマップから、所定の時間毎の残留
量を算出する。In this case, in steps 1 and 2, the residual exhaust gas recirculation amount is obtained from the intake air amount when the first injection is judged in the same manner as in FIG. 5, and in step 3, the engine speed and throttle The opening is read, and in step 4, the residual amount for each predetermined time is calculated from the map as shown in FIG.
【００４２】排気の残留量は時間の経過に伴って減少
し、そのときのエンジン回転数、スロットル開度などに
より算出できるが、最初の吸入空気量が小さいほど、残
留量が多くかつ減衰時間は長くなる。The residual amount of exhaust gas decreases with the passage of time, and can be calculated from the engine speed, throttle opening, etc. at that time. However, the smaller the initial intake air amount, the greater the residual amount and the decay time. become longer.
【００４３】図４に戻って、ステップ９では残留量に応
じて、吸気行程と圧縮行程での噴射量の分担率が補正さ
れる。燃料噴射量の分担率は、図９にａで示すように、
基本的には混合気の当量比に応じて決まり、成層燃焼の
当量比が小さく（混合気の薄い）圧縮行程のみでの噴射
から、当量比が大きく（混合気が濃く）吸気行程だけで
噴射する均質燃焼との間においては、当量比が大きくな
るにしたがって吸気行程での噴射分担率が比例的に増加
していく。Returning to FIG. 4, in step 9, the share of the injection amount in the intake stroke and the injection stroke is corrected according to the residual amount. The share of the fuel injection amount is as shown by a in FIG.
Basically, it is decided according to the equivalence ratio of the air-fuel mixture, and injection is performed only in the compression stroke where the equivalence ratio of stratified combustion is small (the air-fuel mixture is thin), and injection is performed only in the intake stroke where the equivalence ratio is large (the air-fuel mixture is rich) In the homogeneous combustion, the injection sharing ratio in the intake stroke increases proportionally as the equivalence ratio increases.
【００４４】しかし、還流排気の残留量が多いときは、
燃料噴射の分担率をそのままとすると、とくに均質燃焼
の性質が強まる吸気行程での分担率が大きい領域で、燃
焼が著しく悪化する。However, when the residual amount of the recirculated exhaust gas is large,
If the share of fuel injection is left as it is, combustion will be significantly deteriorated particularly in the region where the share of fuel injection is large in the intake stroke where the property of homogeneous combustion is enhanced.
【００４５】図１０は排気の残留量が大きいときほど、
安定燃焼するための吸気行程分担率が小さくなること示
している。つまり、残留量が大きいときは、吸気行程で
の噴射割合をそれだけ小さくする必要がある。FIG. 10 shows that when the residual amount of exhaust gas is large,
It is shown that the intake stroke share rate for stable combustion becomes smaller. That is, when the residual amount is large, it is necessary to reduce the injection ratio in the intake stroke by that amount.
【００４６】また、図１１は排気の残留量と安定度が確
保できる当量比の関係を示すものであるが、残留量が大
きくなるほど安定燃焼を維持するのに必要な当量比は大
きくなる。Further, FIG. 11 shows the relationship between the residual amount of exhaust gas and the equivalence ratio capable of ensuring stability. The larger the residual amount, the greater the equivalence ratio required to maintain stable combustion.
【００４７】そこで、この実施の形態では、図９にｂで
示すように、当量比が徐々に大きくなって、吸気行程で
の分担率が５０％に達したならば、そのときの還流排気
の残留量との関係で、安定度が確保できる当量比まで、
その分担率が５０％を維持したまま当量比の大きい側に
移行させるように補正する。排気の残留量が小さけれ
ば、分担率５０％を維持する領域が狭くなり、大きけれ
ば領域が比例的に広がり、より当量比の大きい方まで分
担率５０％の領域が拡大される。このようにして、排気
の残留量に応じて２回噴射時の圧縮行程での分担率が、
安定燃焼の可能な成層燃焼を確保できる範囲に維持され
る。Therefore, in this embodiment, as shown by b in FIG. 9, if the equivalence ratio gradually increases and the share rate in the intake stroke reaches 50%, the recirculated exhaust gas at that time is In relation to the residual amount, up to an equivalence ratio that can ensure stability,
The correction is performed so that the share ratio is maintained at 50% and the equivalence ratio is increased. If the residual amount of exhaust gas is small, the region in which the sharing ratio of 50% is maintained becomes narrow, and if it is large, the region expands proportionally, and the region of sharing ratio of 50% is expanded to the one with a larger equivalence ratio. In this way, the share rate in the compression stroke at the time of two injections according to the residual amount of exhaust gas becomes
It is maintained within the range where stable combustion and stable stratified combustion can be secured.
【００４８】この実施形態において、分担率５０％は排
気還流時の安定限界を示すものであり、必ずしも分担率
５０％に限定されるわけではない。また、このように安
定限界での分担率を維持したまま当量比の大きい側へ移
行させるので、当量比を大きくしても点火栓近傍の混合
気が過濃となることを防止できる。In this embodiment, the sharing rate of 50% indicates the stability limit during exhaust gas recirculation, and is not necessarily limited to the sharing rate of 50%. Further, since the equivalence ratio is increased while maintaining the sharing ratio at the stability limit, it is possible to prevent the air-fuel mixture near the spark plug from becoming rich even if the equivalence ratio is increased.
【００４９】次にステップ１０において、補正された分
担率に基づいて、吸気行程と圧縮行程での燃料噴射量
と、燃料噴射時期が計算される。また、同時にその当量
比にするための必要なスロットル開度が算出される。Next, at step 10, the fuel injection amount and the fuel injection timing in the intake stroke and the compression stroke are calculated based on the corrected share rate. At the same time, the throttle opening required for achieving the equivalent ratio is calculated.
【００５０】ステップ１２ではこの演算されたタイミン
グとパルス幅をもって燃料噴射弁が駆動され、かつスロ
ットル開度が補正されるのである。In step 12, the fuel injection valve is driven with the calculated timing and pulse width, and the throttle opening is corrected.
【００５１】なお、ステップ７において、２回噴射が判
定されないときは、成層燃焼または均質燃焼での１回噴
射であり、ステップ１１に移行して、成層燃焼と均質燃
焼のそれぞれに応じて、必要な燃料噴射量、噴射時期、
スロットル開度が演算された上、ステップ１２に進んで
燃料噴射弁とスロットル開度の制御が行われる。When it is determined in step 7 that the injection is not performed twice, it means that the injection is a single injection in stratified combustion or homogeneous combustion. Then, the process proceeds to step 11 and is necessary depending on each of stratified combustion and homogeneous combustion. Fuel injection amount, injection timing,
After the throttle opening is calculated, the routine proceeds to step 12, where the fuel injection valve and the throttle opening are controlled.
【００５２】以上のように構成され、次に全体的な作用
について図１２を参照しながら説明する。With the above structure, the overall operation will be described with reference to FIG.
【００５３】機関の低負荷運転時などアクセル開度の小
さい運転状態では、超希薄混合気での成層燃焼域とな
り、燃料噴射時期が圧縮行程の後半となり、点火栓近傍
に可燃混合気層を形成しての成層燃焼を行う。In an operating state where the accelerator opening is small, such as during low load operation of the engine, it becomes a stratified combustion region with an ultra-lean mixture, the fuel injection timing is in the latter half of the compression stroke, and a combustible mixture layer is formed near the spark plug. Then, stratified combustion is performed.
【００５４】このとき、排気還流制御弁１５が開かれて
排気還流が行われ、吸気中に混入した排気によりＮＯｘ
の発生を抑制する。成層燃焼では点火栓８の近傍に燃料
が集中し、超希薄混合気であっても排気還流により燃焼
の安定が損なわれることはない。At this time, the exhaust gas recirculation control valve 15 is opened to perform exhaust gas recirculation, and NOx is mixed with the exhaust gas mixed in the intake air.
Suppress the occurrence of. In stratified combustion, fuel is concentrated near the spark plug 8, and even if it is an ultra-lean air-fuel mixture, exhaust gas recirculation does not impair combustion stability.
【００５５】アクセル開度が増加して負荷が大きくなる
と、成層燃焼域から理論空燃比の混合気での均質燃焼域
へと移行するが、この移行過程において均質希薄燃焼域
を通過する。この均質希薄燃焼域では、空燃比は成層燃
焼よりは濃いが、燃焼の安定性を保つために排気還流を
停止する。When the accelerator opening is increased and the load is increased, the stratified charge combustion region transitions to the homogeneous combustion region in the stoichiometric air-fuel mixture, and in the transition process, the homogeneous lean combustion region is passed. In this homogeneous lean combustion region, the air-fuel ratio is richer than that in stratified combustion, but the exhaust gas recirculation is stopped to maintain combustion stability.
【００５６】したがって直ちに排気還流制御弁１５が閉
じられるが、吸気中に残留する還流排気のため、燃焼室
内の還流排気量は直ちにはゼロにはならず、そのときの
運転条件に応じて徐々に減少していく。このように実質
的に排気還流されている状態で、均質希薄燃焼に移行す
ると、燃焼の安定性が著しく損なわれてしまう。Therefore, although the exhaust gas recirculation control valve 15 is immediately closed, the amount of recirculated exhaust gas in the combustion chamber does not immediately become zero because of the recirculated exhaust gas remaining in the intake air, and gradually changes according to the operating conditions at that time. Will decrease. In this state where the exhaust gas is substantially recirculated to the exhaust gas, if the homogeneous lean combustion is started, the stability of combustion is significantly impaired.
【００５７】希薄燃焼域では、燃料の噴射が吸気行程と
圧縮行程の２回に分けて行われるが、吸気行程での噴射
割合が多くなると、燃料の予混合割合が多くなり、点火
栓近傍に安定して着火する可燃混合気層を形成するのが
難しくなる。つまり、吸気行程での噴射割合が多いとき
は均質燃焼に近づき、全体の空燃比としては希薄混合気
であるため、還流排気の存在により燃焼が不安定になる
のである。In the lean burn region, the fuel injection is divided into two parts, the intake stroke and the compression stroke. When the injection ratio in the intake stroke increases, the premixing ratio of the fuel increases, and the fuel near the spark plugs increases. It becomes difficult to form a combustible mixture layer that stably ignites. In other words, when the injection ratio in the intake stroke is high, the combustion approaches homogeneity combustion, and since the overall air-fuel ratio is a lean air-fuel mixture, the combustion becomes unstable due to the presence of the recirculation exhaust gas.
【００５８】そこで、この２回噴射領域においては、そ
のときの運転状態に応じて決まる還流排気の残留量を演
算し、この残留量が多いときほど、圧縮行程での燃料分
担率が大きい時間が長くなるように補正する。Therefore, in this double injection region, the residual amount of the recirculated exhaust gas, which is determined according to the operating state at that time, is calculated, and the greater the residual amount, the longer the fuel sharing rate in the compression stroke is. Correct so that it becomes longer.
【００５９】このため、排気の残留量が多く、燃焼の悪
化しやすいときは、吸気行程の噴射割合が小さく、圧縮
行程での噴射により、点火栓近傍に可燃混合気層を維持
形成しやする。これにより、残留排気が存在する間は、
実質的に成層燃焼を維持して燃焼の安定性を確保する。
つまり、燃焼安定性が保てる当量比までそのまま待つの
である。そして当量比（機関負荷）が大きくなり、排気
の残留があっても安定性が確保されるときは、分担率５
０％を越えて吸気行程での噴射割合を増やしていき、つ
いには２回噴射から吸気行程だけの１回噴射に移行し、
理論空燃比による均質予混合燃焼に入る。Therefore, when the residual amount of exhaust gas is large and combustion is likely to deteriorate, the injection ratio in the intake stroke is small, and the combustible air-fuel mixture layer is formed near the spark plug by the injection in the compression stroke. . This ensures that while residual exhaust is present,
Substantially maintain stratified combustion to ensure combustion stability.
In other words, it waits as it is until the equivalence ratio where combustion stability can be maintained. When the equivalence ratio (engine load) becomes large and stability is secured even if exhaust gas remains, the share ratio 5
The injection ratio in the intake stroke is increased to exceed 0%, and finally the injection is shifted from the double injection to the single injection in the intake stroke.
Enter into homogeneous premixed combustion with stoichiometric air-fuel ratio.
【００６０】このようにして、２回噴射時の希薄燃焼域
での安定性を吸気行程の噴射分担率を制限すことにより
確保し、成層燃焼域からの運転のつながり特性を良好に
維持する。In this way, stability in the lean burn region at the time of double injection is secured by limiting the injection share of the intake stroke, and good connection characteristics of operation from the stratified burn region are maintained.
【００６１】次に均質燃焼域では、再び排気還流制御弁
を開き、所定の排気還流を行い、ＮＯｘの発生を減少さ
せる。なお、この理論空燃比での均質予混合燃焼では、
排気還流を行っても燃焼の悪化の影響は小さく、ただし
機関高出力の確保を優先する意味から、排気還流率は成
層燃焼に比較して小さく設定している。Next, in the homogeneous combustion region, the exhaust gas recirculation control valve is opened again to carry out a predetermined exhaust gas recirculation to reduce the generation of NOx. In addition, in this homogeneous air-fuel ratio homogeneous premixed combustion,
Even if exhaust gas recirculation is performed, the effect of deterioration of combustion is small, but in order to prioritize securing high engine output, the exhaust gas recirculation rate is set smaller than in stratified charge combustion.
【００６２】ところで、排気の残留量に対応しての燃料
噴射の分担率であるが、上記の補正方法では、成層燃焼
から２回噴射の希薄燃焼への移行時に、吸気行程での燃
料噴射の分担率５０％に達したときに、そのときの残留
排気量にもよるが、安定性が確保できる当量比まで、そ
のまま分担率５０％を維持することで、実質的な成層燃
焼を可能とし、燃焼安定性を維持している。この場合、
吸気行程噴射の分担率が５０％から高くなり始める領域
は、一点鎖線で示すように、それぞれそのときの排気の
残留量に応じて変化し、上記したとおり、残留量が多い
ときほど分担率５０％の領域が長くなる。By the way, regarding the fuel injection share ratio corresponding to the residual amount of exhaust gas, in the above correction method, the fuel injection in the intake stroke is performed at the time of transition from stratified charge combustion to lean combustion of double injection. When the share ratio reaches 50%, it depends on the residual exhaust gas amount at that time, but by maintaining the share ratio of 50% as it is, it becomes possible to realize substantially stratified combustion, Maintains combustion stability. in this case,
The region where the share of intake stroke injection starts to increase from 50% changes according to the residual amount of exhaust gas at that time, as indicated by the alternate long and short dash line. As described above, the share of 50 increases as the residual amount increases. % Area becomes longer.
【００６３】また、残留する排気の還流量を、図７のよ
うに、最初に２回噴射が行われたときに算出するだけで
なく、その後も一定時間毎に残留量を算出しているとき
は、そのときどきの残留量に応じて、燃料噴射の分担率
の補正を行うことができ、この場合にはさらに正確に還
流排気の残留量に対応した制御が行え、燃費も改善でき
る。Further, when the residual exhaust gas recirculation amount is calculated not only when the injection is first performed twice as shown in FIG. 7 but also when the residual amount is calculated at regular intervals thereafter. Can correct the share of fuel injection depending on the residual amount at that time, and in this case, the control corresponding to the residual amount of the recirculated exhaust gas can be performed more accurately and the fuel consumption can be improved.
【００６４】ところで、成層燃焼から均質燃焼への切換
が緩やかに行われると、２回噴射の希薄燃焼が維持され
る期間が長くなり、分担率５０％となる当量比に達する
までの間に排気の残留量がゼロになってしまうこともあ
る。分担率５０％の領域を維持する上記した補正方法で
は、このようなときには補正が行われなくなる。By the way, when the stratified combustion is gradually switched to the homogeneous combustion, the period during which the lean injection of the two injections is maintained becomes longer, and the exhaust gas is exhausted until the equivalence ratio becomes 50%. The residual amount of may become zero. In the above-described correction method that maintains the region where the sharing ratio is 50%, the correction is not performed in such a case.
【００６５】そこで、他の実施の形態として、図１３に
も示すように、吸気行程での噴射分担率５０％となる前
の、他えば１０％、２０％、３０％、４０％などのとき
に、当量比にかかわらず同一の分担率を維持するように
してもよい。Therefore, as another embodiment, as shown in FIG. 13, when the injection share ratio in the intake stroke is not 50%, other cases are 10%, 20%, 30%, 40%, etc. In addition, the same sharing rate may be maintained regardless of the equivalence ratio.
【００６６】もちろんこの場合は、燃焼安定限界との関
係で、排気の残留量が大きいときほど吸気行程の分担率
が低く維持されることになる。In this case, of course, in consideration of the combustion stability limit, the larger the residual amount of exhaust gas, the lower the share of the intake stroke will be maintained.
【００６７】また、これに限らず、残留する排気還流量
に基づいて燃焼の安定性が確保できるように当量比との
関係で、分担率を補正するならば、あらゆるものが本発
明の範囲に含まれる。Further, not limited to this, as long as the share ratio is corrected in relation to the equivalence ratio so that the stability of combustion can be ensured based on the remaining exhaust gas recirculation amount, all of them fall within the scope of the present invention. included.
【００６８】また、上記においては、残留する還流排気
量の検出を２回噴射許可判定後、一定時間毎に行い、そ
の都度分担率の補正を行うようにしているが、２回噴射
の許可判定時に最初に求めた残留量と、そのときの運転
条件（エンジン回転数、スロットル開度など）によって
決まる残留排気の減少特性を推定し、これに基づいて分
担率の補正を行うこともできる。Further, in the above description, the residual recirculation exhaust gas amount is detected every two fixed times after the injection permission determination, and the share ratio is corrected each time. It is also possible to estimate the residual exhaust gas decrease characteristic determined by the residual amount initially obtained and the operating condition (engine speed, throttle opening, etc.) at that time, and correct the share rate based on this.
【図１】本発明の実施の形態を示す断面図である。FIG. 1 is a sectional view showing an embodiment of the present invention.
【図２】同じく全体構成の概略平面図である。FIG. 2 is likewise a schematic plan view of the overall configuration.
【図３】燃焼領域特性を示す説明図である。FIG. 3 is an explanatory diagram showing combustion region characteristics.
【図４】燃料分担率を設定するためのフローチャートで
ある。FIG. 4 is a flowchart for setting a fuel sharing rate.
【図５】排気の残留量を算出するためのフローチャート
である。FIG. 5 is a flowchart for calculating a residual amount of exhaust gas.
【図６】排気の残留量と吸入空気量の関係を示すマップ
である。FIG. 6 is a map showing the relationship between the residual amount of exhaust gas and the intake air amount.
【図７】排気の残留量を算出するための別のフローチャ
ートである。FIG. 7 is another flowchart for calculating the residual amount of exhaust gas.
【図８】排気の残留量の減少特性を示すマップである。FIG. 8 is a map showing a characteristic of reducing a residual amount of exhaust gas.
【図９】燃料分担率の補正特性を示す説明図である。FIG. 9 is an explanatory diagram showing a correction characteristic of a fuel sharing ratio.
【図１０】燃料分担率と排気の残留量とに基づく安定限
界の関係を示す説明図である。FIG. 10 is an explanatory diagram showing a relationship of a stability limit based on a fuel sharing ratio and a residual amount of exhaust gas.
【図１１】当量比と排気の残留量とに基づく安定限界の
関係を示す説明図である。FIG. 11 is an explanatory diagram showing a relationship of a stability limit based on an equivalence ratio and a residual amount of exhaust gas.
【図１２】運転条件との燃焼の切換、排気残留量の特性
を示す説明図である。FIG. 12 is an explanatory diagram showing characteristics of switching of combustion with operating conditions and residual amount of exhaust gas.
【図１３】燃料分担率の補正特性の他の例を示す説明図
である。FIG. 13 is an explanatory diagram showing another example of the correction characteristic of the fuel sharing ratio.
【符号の説明】 １ エンジン本体 ２ 吸気通路 ３ 排気通路 ６ 燃料噴射弁 ７ 燃焼室 ８ 点火栓 １３ 排気還流通路 １５ 排気還流制御弁 ２０ コントロールユニット[Explanation of symbols] 1 engine body 2 Intake passage 3 exhaust passage 6 Fuel injection valve 7 Combustion chamber 8 spark plug 13 Exhaust gas recirculation passage 15 Exhaust gas recirculation control valve 20 control unit
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｆ０２Ｄ 41/04 Ｆ０２Ｄ 41/04 ３３５Ｃ 41/34 41/34 Ａ Ｅ 43/00 ３０１ 43/00 ３０１Ｈ ３０１Ｎ Ｆ０２Ｍ 25/07 ５５０ Ｆ０２Ｍ 25/07 ５５０Ｒ ５７０ ５７０Ａ 45/02 45/02 (58)調査した分野(Int.Cl.7，ＤＢ名) F02M 39/00 - 71/04 F02M 25/06 - 25/07 F02D 41/00 - 45/00 ─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. 7 Identification Code FI F02D 41/04 F02D 41/04 335C 41/34 41/34 A E 43/00 301 43/00 301H 301N F02M 25/07 550 F02M 25/07 550R 570 570A 45/02 45/02 (58) Fields investigated (Int.Cl. 7 , DB name) F02M 39/00-71/04 F02M 25/06-25/07 F02D 41/00-45 / 00
Claims (5)
射時期を圧縮行程に設定することで成層燃焼を行い、吸
気行程に設定することで均質燃焼を行うと共に、成層燃
焼から均質燃焼への切換時には吸気行程と圧縮行程の２
回に分けて燃料を噴射して希薄燃焼を行う筒内直接噴射
式火花点火内燃機関において、排気の一部を吸気中に還
流する排気還流手段と、この排気還流を成層燃焼から前
記希薄燃焼への切換に伴い遮断する手段と、排気還流の
遮断時に吸気系に残存する還流排気の残留量を計測する
手段と、前記希薄燃焼での吸気行程と圧縮行程での燃料
噴射の分担率を前記還流排気の残留量に応じて補正する
手段とを備えることを特徴とする筒内噴射式火花点火内
燃機関の燃料制御装置。1. A jetting straight Se' charge into the cylinder, together with the injection timing of the fuel subjected to stratified combustion by setting the compression stroke, performing homogeneous combustion by setting the intake stroke, the stratified charge combustion When switching to homogeneous combustion, the intake stroke and compression stroke are 2
In the cylinder direct injection spark ignition internal combustion engine which performs an injection to lean combustion fuel is divided in time, and exhaust gas recirculation means for recirculating a part of exhaust during inspiration, before the exhaust gas recirculation from the stratified combustion
Means for blocking due to switching to serial lean combustion, and means for measuring the residual amount of recirculated exhaust gas remaining in the intake system at the time of cutoff of the exhaust gas recirculation, sharing of the fuel injection in the intake stroke and the compression stroke in the lean burn fuel control apparatus for a direct injection spark ignition internal combustion engine, characterized in that it comprises a means for correcting the rate to the residual amount of the recirculated exhaust gas.
の燃料噴射の分担率の大きい領域を還流排気の残留量に
応じて変化させる請求項１に記載の筒内噴射式火花点火
内燃機関の燃料制御装置。2. The in-cylinder injection spark ignition internal combustion engine according to claim 1, wherein the correction means changes a region in which the share of fuel injection in the compression stroke is larger than that in the intake stroke in accordance with the residual amount of the recirculated exhaust gas. Fuel control system.
の燃料噴射の分担率が大きい領域をそのときの空燃比に
応じて変化させる請求項１または２に記載の筒内噴射式
火花点火内燃機関の燃料制御装置。3. The in-cylinder injection spark ignition according to claim 1 or 2, wherein the correction means changes a region in which a fuel injection share is larger in a compression stroke than in an intake stroke in accordance with an air-fuel ratio at that time. Fuel control device for internal combustion engine.
還流排気遮断時の吸入空気量に応じて推定する請求項１
〜３のいずれか一つに記載の筒内噴射式火花点火内燃機
関の燃料制御装置。4. The residual amount measuring means estimates the residual amount of the recirculated exhaust gas according to the intake air amount when the recirculated exhaust gas is shut off.
4. The fuel control device for a cylinder injection type spark ignition internal combustion engine according to any one of items 1 to 3.
定残留量を基にしてエンジン回転数と負荷に応じて所定
の時間毎の残留量を推定する請求項４に記載の筒内噴射
式火花点火内燃機関の燃料制御装置。5. The in-cylinder injection according to claim 4, wherein the residual amount measuring means estimates the residual amount for each predetermined time in accordance with the engine speed and the load based on the estimated residual amount when the recirculation exhaust gas is shut off. -Type spark ignition internal combustion engine fuel control system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17594497A JP3395583B2 (en) | 1997-07-01 | 1997-07-01 | Fuel control system for in-cylinder injection spark ignition internal combustion engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17594497A JP3395583B2 (en) | 1997-07-01 | 1997-07-01 | Fuel control system for in-cylinder injection spark ignition internal combustion engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1122507A JPH1122507A (en) | 1999-01-26 |
| JP3395583B2 true JP3395583B2 (en) | 2003-04-14 |
Family
ID=16004992
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17594497A Expired - Lifetime JP3395583B2 (en) | 1997-07-01 | 1997-07-01 | Fuel control system for in-cylinder injection spark ignition internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3395583B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102004043595B4 (en) * | 2004-09-06 | 2014-10-09 | Robert Bosch Gmbh | Method for operating a direct injection internal combustion engine with an exhaust gas recirculation and apparatus for carrying out the method |
| JP4148233B2 (en) | 2005-03-29 | 2008-09-10 | トヨタ自動車株式会社 | Engine fuel injection control device |
| CN110284982A (en) * | 2019-06-19 | 2019-09-27 | 东风汽车集团有限公司 | A kind of method for handover control of direct spray petrol engine in cylinder from stratified combustion to homogeneous combustion |
-
1997
- 1997-07-01 JP JP17594497A patent/JP3395583B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH1122507A (en) | 1999-01-26 |
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