JP2006329117A - Controller for direct injection spark ignition type internal combustion engine - Google Patents

Controller for direct injection spark ignition type internal combustion engine Download PDF

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JP2006329117A
JP2006329117A JP2005155679A JP2005155679A JP2006329117A JP 2006329117 A JP2006329117 A JP 2006329117A JP 2005155679 A JP2005155679 A JP 2005155679A JP 2005155679 A JP2005155679 A JP 2005155679A JP 2006329117 A JP2006329117 A JP 2006329117A
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fuel
injection
fuel injection
inner cavity
spray
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Daisuke Tanaka
大輔 田中
Taisuke Shiraishi
泰介 白石
Akira Tayama
彰 田山
Hirobumi Tsuchida
博文 土田
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Nissan Motor Co Ltd
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    • 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
    • Y02T10/12—Improving ICE efficiencies
    • 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

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  • Combustion Methods Of Internal-Combustion Engines (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To generate satisfactory stratified air-fuel mixture air mass and maintain stable stratified combustion without depending on change of environment. <P>SOLUTION: In a normal condition in which distance from a tip of a fuel injection valve to an inner side cavity is longer than length of splitting of fuel spray during a period of fuel injection, fuel is injected by directing for the inner side cavity in a comparatively low load operation region in operation conditions for performing stratified combustion, and fuel is injected by directing for an outer side cavity in a comparatively high load operation region. When distance Hb from an injection hole of the fuel injection valve to collision against a wall face of the inner side cavity is smaller than length of splitting Lb of fuel spray, fuel injection control is switched to inject fuel by directing for the outer side cavity even in a load region where fuel is injected by directing for the inner side cavity in the normal condition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、直噴火花点火式内燃機関の制御装置に関し、特に、環境変化によらず良好な成層燃焼を実現する技術に関する。   The present invention relates to a control device for a direct-injection spark-ignition internal combustion engine, and more particularly to a technique for realizing good stratified combustion regardless of environmental changes.

燃料噴射弁から筒内に燃料を直接噴射し、筒内に成層化した混合気に火花点火を行う直噴火花点火式内燃機関では、混合気のサイズによりエンジンの出力が制御可能となり、燃料噴射量（噴射期間）により負荷が調整されることとなる。これにより、スロットル弁の絞りを行う必要がなく、ポンピングロスがなくなるため、特に低・中負荷において大幅に燃料消費が低減できることが知られている。   In a direct-injection spark-ignition internal combustion engine that directly injects fuel into the cylinder from the fuel injection valve and ignites the stratified mixture in the cylinder, the engine output can be controlled by the size of the mixture. The load is adjusted by the amount (injection period). This eliminates the need to throttle the throttle valve and eliminates the pumping loss, so that it is known that fuel consumption can be significantly reduced, especially at low and medium loads.

このような直噴火花点火式内燃機関では着実に点火・燃焼せしめるために、機関の回転速度・負荷に応じて、筒内に適切な大きさ・空燃比の混合気塊を、確実に成層化した状態で形成することが重要である。
特許文献１には、燃料噴射弁から噴射される燃料噴霧に直接火花点火を行う手法や、燃料噴射弁から噴射される燃料噴霧をピストンキャビティ壁面へ衝突させ、キャビティ形状に沿った噴霧の循環流を形成し、均質な混合気をキャビティ上空に配置する手法が開示されている。 In such a direct-injection spark-ignition internal combustion engine, in order to steadily ignite and burn, an air-fuel mixture with an appropriate size and air-fuel ratio is stratified reliably in the cylinder according to the engine speed and load. It is important to form in such a state.
Patent Document 1 discloses a technique in which spark ignition is directly performed on a fuel spray injected from a fuel injection valve, or a fuel spray injected from a fuel injection valve is caused to collide with a piston cavity wall surface to circulate the spray along the cavity shape. And a method of disposing a homogeneous air-fuel mixture over the cavity is disclosed.

ところで、ピストンキャビティを有する内燃機関において、吸気圧力や吸気温度など環境パラメータが変化した場合に均質燃焼に切り換えて点火プラグの燻りを回避した場合はポンピングロスが発生し燃費が悪化する問題がある。
これに対して特許文献２には、燃料噴射時期を進角、または点火時期を遅角させて点火時期における点火プラグギャップ近傍の混合気のリッチ程度を抑制する方法が開示されている。
特開平１１−８２０２８号公報 特開平１０-１５１９７２号公報 By the way, in an internal combustion engine having a piston cavity, when environmental parameters such as intake pressure and intake air temperature are changed, when switching to homogeneous combustion and avoiding the spark plug from being burned, a pumping loss occurs and fuel consumption deteriorates.
On the other hand, Patent Document 2 discloses a method of suppressing the richness of the air-fuel mixture near the spark plug gap at the ignition timing by advancing the fuel injection timing or retarding the ignition timing.
JP-A-11-82028 Japanese Patent Laid-Open No. 10-151972

しかしながら、特許文献２のように単純なボウル形状のピストンキャビティに対して噴射時期を進角しただけでは、点火プラグ周辺の混合気濃度のリッチ度合いを抑制できる可能性があるが、噴霧特性の変化によりキャビティ底面もしくは壁面への噴霧の衝突位置がかわり混合気がキャビティからはみ出すなど、良好な成層混合気塊が生成されず、スモークやＨＣレベルが悪化する恐れがある。   However, just by advancing the injection timing with respect to a simple bowl-shaped piston cavity as in Patent Document 2, there is a possibility that the richness of the air-fuel mixture concentration around the spark plug may be suppressed. As a result, the collision position of the spray on the bottom surface or the wall surface of the cavity changes, and the air-fuel mixture protrudes from the cavity. For this reason, a good stratified air-fuel mixture is not generated, and smoke and HC levels may be deteriorated.

良好な成層混合気塊を生成するためには基本的にキャビティに指向した形で燃料を噴射する必要があるが、進角可能範囲がキャビティとの位置関係により限定されてしまい、十分な効果が得られるとは言い難い。
本発明は、このような従来の課題に着目してなされたもので、キャビティ形状と燃料噴射制御とを適切に設定することにより、環境変化によらず良好な成層混合気塊を生成して安定した成層燃焼を維持できるようにすることを目的とする。 In order to generate a good stratified air-fuel mixture, it is basically necessary to inject fuel in a direction directed to the cavity, but the advanceable range is limited by the positional relationship with the cavity, and a sufficient effect is achieved. It is hard to say that it is obtained.
The present invention has been made paying attention to such conventional problems. By appropriately setting the cavity shape and the fuel injection control, a good stratified air-fuel mixture can be generated and stabilized regardless of environmental changes. It aims to be able to maintain stratified combustion.

このため本発明は、まず、ピストン冠面に設けられるピストンキャビティについては、燃焼室上面の略中央部に設置した燃料噴射弁から噴射される燃料噴霧の中心軸と略同一中心軸となるような大径ボウル状の外側キャビティと、該外側キャビティに内包された小径ボウル状の内側キャビティとで構成される二重構造とする。
そして、燃料噴霧の***長さを判定し、燃料噴射期間中において、燃料噴射弁の噴孔から燃料噴霧が内側キャビティ壁面に衝突するまでの距離が燃料噴霧の***長さより大きい通常の環境のときは、成層燃焼を実施する運転状態の中で比較的低負荷運転領域では内側キャビティに指向させて燃料を噴射し、比較的高負荷運転領域においては外側キャビティに指向させて燃料を噴射する。 Therefore, according to the present invention, first, the piston cavity provided on the piston crown surface has substantially the same central axis as the central axis of the fuel spray injected from the fuel injection valve installed at the substantially central portion of the upper surface of the combustion chamber. A double structure is constituted of a large-diameter bowl-shaped outer cavity and a small-diameter bowl-shaped inner cavity enclosed in the outer cavity.
Then, the split length of the fuel spray is determined, and during the fuel injection period, when the distance from the nozzle hole of the fuel injection valve to the collision of the fuel spray with the inner cavity wall surface is larger than the split length of the fuel spray In the operation state in which stratified combustion is performed, the fuel is injected toward the inner cavity in the relatively low load operation region, and the fuel is injected toward the outer cavity in the relatively high load operation region.

一方、吸気圧力や吸気温度など環境パラメータが変化して、燃料噴射弁の先端から内側キャビティまでの距離が燃料噴霧の***長さ以下となったときは、通常の環境では主に外側キャビティに指向させて燃料を噴射するように燃料噴射制御を切り換える構成とした。   On the other hand, when environmental parameters such as intake air pressure and intake air temperature change and the distance from the tip of the fuel injector to the inner cavity is less than the split length of the fuel spray, it is mainly directed to the outer cavity in the normal environment. The fuel injection control is switched so that the fuel is injected.

成層燃焼を実施している運転状態の中で噴射点から噴射された燃料噴霧が内側キャビティ底面へ衝突する点までの距離よりも噴霧の***長さが短い場合は、通常は噴射時期や噴霧角の設定で内側キャビティへ指向させて燃料噴射する負荷領域でも、外側キャビティへ指向させて燃料噴射する。
これにより、燃料噴霧が***し液滴となる以前の液柱（液膜）状態で壁面に衝突し、局部的に過濃混合気を形成してしまう問題を抑制でき、過濃混合気により生成されるスモークによりプラグが燻る問題を回避できる。 When the split length of the spray is shorter than the distance from the injection point to the point where the fuel spray injected from the injection point collides with the bottom of the inner cavity in the operating state where stratified combustion is being performed, the injection timing and spray angle are usually Even in a load region in which fuel is directed toward the inner cavity with this setting, fuel is directed toward the outer cavity.
As a result, it is possible to suppress the problem of colliding with the wall surface in the liquid column (liquid film) state before the fuel spray breaks up into droplets and locally forming a rich mixture, which is generated by the rich mixture. It is possible to avoid the problem that the plug is struck by the smoke.

また、外側キャビティへ指向させて燃料噴射をおこなうことで、噴射タイミングを十分に早期に設定することができるため、十分な気化時間が確保されてこの点でも過濃混合気の生成を抑制できる。
また、噴霧先端を外側キャビティによってホールドできるため、混合気が希薄となりすぎることはなく、ＨＣの悪化を抑制することができる。 Moreover, since the injection timing can be set sufficiently early by directing the fuel toward the outer cavity, a sufficient vaporization time can be secured, and the generation of the rich mixture can also be suppressed in this respect.
Further, since the spray tip can be held by the outer cavity, the air-fuel mixture does not become too lean, and deterioration of HC can be suppressed.

また、混合気塊のサイズが大きくなるため、燃費は多少悪化するが、従来の吸気ポート噴射による均質燃焼よりも燃費の良い運転が実現できる。   Further, since the air-fuel mixture size increases, the fuel efficiency is somewhat deteriorated, but an operation with better fuel efficiency than the conventional homogeneous combustion by the intake port injection can be realized.

以下、本発明の実施形態を図面に基づいて説明する。
図１は本発明の実施形態にかかる直噴火花点火式内燃機関の構成を示す。
この内燃機関は、シリンダヘッド１、シリンダブロック２及びピストン３により構成される燃焼室４を有し、排気バルブ５及び吸気バルブ６を介して、吸気ポート７から新気を導入及び排気ポート８から排気を排出する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a configuration of a direct injection spark ignition internal combustion engine according to an embodiment of the present invention.
This internal combustion engine has a combustion chamber 4 composed of a cylinder head 1, a cylinder block 2 and a piston 3, and introduces fresh air from an intake port 7 through an exhaust valve 5 and an intake valve 6 and from an exhaust port 8. Exhaust the exhaust.

前記各バルブを駆動するカム軸端には燃料ポンプ９が配置されている。燃料ポンプ９により加圧された燃料は燃料配管１０を介して燃料噴射弁１１より燃焼室４へ噴射可能である。前記燃料ポンプ９は、別に配置された電気モータにより駆動される形式としてもよい。
前記燃料噴射弁１１は燃焼室４の略中央部に配置され、マルチホール噴射弁に加えて、例えば、特開２０００−３０３９３６に示されるような少なくとも２つの異なる燃料噴霧角を制御可能な仕様、もしくは針弁が本体の外側に突出して開く外開きタイプの噴射弁、針弁のリフト量を可変な圧電素子駆動型のピエゾ式噴射弁などが含まれるものとする。 A fuel pump 9 is disposed at the end of the cam shaft that drives each valve. The fuel pressurized by the fuel pump 9 can be injected into the combustion chamber 4 from the fuel injection valve 11 via the fuel pipe 10. The fuel pump 9 may be driven by an electric motor arranged separately.
The fuel injection valve 11 is disposed at a substantially central portion of the combustion chamber 4, and in addition to the multi-hole injection valve, for example, a specification capable of controlling at least two different fuel spray angles as disclosed in JP 2000-303936, Alternatively, an outward opening type injection valve in which the needle valve protrudes to the outside of the main body, a piezoelectric element drive type piezoelectric injection valve in which the lift amount of the needle valve is variable, and the like are included.

ピストン３の燃料噴射弁１１に対面する冠面には、前記燃料噴射弁１１から噴射される燃料噴霧の中心軸と略同一中心軸となるような小径ボウル状の内側キャビティ３ａと、該内側キャビティ３ａを内包する大径ボウル状の外側キャビティ３ｂからなる二重キャビティが形成されている。
そして、前記燃料噴射弁１１から噴射された燃料は、主に前記内側キャビティ３a及び外側キャビティ３bに成層化された混合気塊を形成する。この混合気は、前記燃料噴射弁１１に隣接して燃焼室４の略中央部に配置された点火プラグ１２により点火・燃焼せしめられる。 On the crown surface of the piston 3 facing the fuel injection valve 11, there is a small-diameter bowl-shaped inner cavity 3 a that is substantially the same central axis as the central axis of fuel spray injected from the fuel injection valve 11, and the inner cavity A double cavity comprising a large-diameter bowl-shaped outer cavity 3b containing 3a is formed.
The fuel injected from the fuel injection valve 11 mainly forms an air-fuel mixture stratified in the inner cavity 3a and the outer cavity 3b. This air-fuel mixture is ignited and combusted by a spark plug 12 disposed in the approximate center of the combustion chamber 4 adjacent to the fuel injection valve 11.

なお、この内燃機関はエンジンコントロールユニット（ＥＣＵ）１３にて統合的に制御される。このためＥＣＵ１３にはクランク角センサ１４からのクランク角信号、アクセル開度センサ１５からのアクセル開度信号、水温センサ１６からの冷却水温度信号等が入力され、これらの信号を基に、前記燃料噴射弁１１、点火プラグ１２、並びに燃料ポンプ９等の各制御を行う。   The internal combustion engine is controlled in an integrated manner by an engine control unit (ECU) 13. For this reason, the ECU 13 receives a crank angle signal from the crank angle sensor 14, an accelerator opening signal from the accelerator opening sensor 15, a cooling water temperature signal from the water temperature sensor 16, and the like. Each control of the injection valve 11, the spark plug 12, the fuel pump 9, etc. is performed.

また、本内燃機関では、燃焼形態として主に、圧縮行程中（特に、圧縮行程後半）に燃料噴射を行うことでリーン運転を実現し燃費を向上させる成層燃焼モードと、吸気行程中（特に吸気行程前半）に燃料噴射を行いストイキ運転（理論空燃比運転）を実現する均質燃焼モードとが設けられており、運転状態に応じて選択されるようになっている。成層燃焼モードとして噴射後の噴霧に直接火花点火を行う手法や噴霧がピストンを介して巻き上がった混合気に火花点火を行う手法などがあるが、本実施形態では成層混合気の形成手法は特に限定しない。   In the internal combustion engine, the combustion mode mainly includes a stratified combustion mode in which a lean operation is realized by performing fuel injection during the compression stroke (particularly in the latter half of the compression stroke) to improve fuel consumption, and during the intake stroke (particularly the intake stroke). A homogeneous combustion mode in which fuel injection is performed in the first half of the stroke and a stoichiometric operation (theoretical air-fuel ratio operation) is realized, and is selected according to the operating state. As a stratified combustion mode, there are a method of performing spark ignition directly on the spray after injection and a method of performing spark ignition on the mixture in which the spray is rolled up through the piston.In this embodiment, the formation method of the stratified mixture is particularly Not limited.

以下、まず本実施形態における通常の設定における運転モード領域について説明する。
図２は、機関の負荷と回転速度による燃焼モード領域と、各領域での混合気分布を示す。成層燃焼モードにおける低負荷域（図示領域ａ）においては、噴射される燃料量が少ないため、内側キャビティ３ａを指向した燃料噴射を行い、コンパクトな混合気を形成して、着火及び燃焼安定性が高く、燃費の良好な運転を行う。 Hereinafter, first, the operation mode region in the normal setting in the present embodiment will be described.
FIG. 2 shows a combustion mode region depending on the engine load and the rotational speed, and an air-fuel mixture distribution in each region. In the low load region (the region a in the figure) in the stratified combustion mode, since the amount of fuel to be injected is small, fuel injection directed toward the inner cavity 3a is performed to form a compact air-fuel mixture, and ignition and combustion stability are improved. Driving with high fuel efficiency.

一方、成層燃焼モードにおける噴射される燃料量が多い高負荷域（図示領域ｂ）においては、内側キャビティ３ａを利用して混合気を形成すると、内側キャビティ３ａ上空にて過濃混合気が形成され、点火プラグ１２のかぶりや燻りの原因ともなる。そのため、成層燃焼モードにおける高負荷時においては、外側キャビティ３ｂを利用して混合気を形成することにより、噴射量が多い条件でもほぼストイキ近傍の混合気を形成できる。   On the other hand, in a high load region (shown region b) where the amount of fuel injected in the stratified combustion mode is large, when an air-fuel mixture is formed using the inner cavity 3a, a rich mixture is formed above the inner cavity 3a. Further, it may cause fogging or squeaking of the spark plug 12. Therefore, at the time of high load in the stratified combustion mode, the air-fuel mixture is formed using the outer cavity 3b, so that the air-fuel mixture in the vicinity of the stoichiometry can be formed even under the condition where the injection amount is large.

これにより、着火及び燃焼安定性に優れた運転が可能となる。なお、噴射された燃料にピストン３を介さずに直接火花点火を行う燃焼方式においても、負荷に応じた内外２つのキャビティ３ａ，３ｂが混合気を受け止める役割を果たすことで、キャビティがない場合に噴霧先端部でピストン周辺への混合気拡散によって希薄混合気が形成されてしまうことを抑制できるため、未燃ＨＣの少ない、燃費の良い運転が実現できる。
本実施形態におけるＥＣＵ１３は、図２に示す特性マップによる領域判定に加えて、図３に示すような燃料噴霧の***長さＬｂと噴射点から噴射された噴霧がピストン３へ衝突する点までの軸方向距離Ｈｂを判定する機能を有し、図４に示すように、吸気圧力、吸気温度、燃料圧力や燃料温度といったパラメータにより***長さの特性をテーブルデータとして保有している。 Thereby, the driving | operation excellent in ignition and combustion stability is attained. Even in the combustion system in which the injected fuel is directly spark-ignited without going through the piston 3, the inner and outer cavities 3a and 3b according to the load play a role of receiving the air-fuel mixture, so that there is no cavity. Since it is possible to suppress the formation of a lean air-fuel mixture due to air-fuel mixture diffusion around the piston at the spray tip, it is possible to realize a fuel-efficient operation with less unburned HC.
In addition to the region determination based on the characteristic map shown in FIG. 2, the ECU 13 in the present embodiment performs the fuel spray split length Lb as shown in FIG. 3 and the point where the spray injected from the injection point collides with the piston 3. It has a function of determining the axial distance Hb. As shown in FIG. 4, the split length characteristic is held as table data according to parameters such as intake pressure, intake temperature, fuel pressure, and fuel temperature.

ここで、燃料噴霧の***長さとは一般的に高圧で噴射された燃料が液滴まで微粒化するのに必要な距離を指すが、ここでは、例えば寒冷地などで気化率が低く、液体の燃料が蒸発を完了できずに液滴が燃料噴射弁の噴孔直下に高密度で存在する領域も広義に噴霧の***長さとして含むものとする（「アトマイゼーション・テクノロジー 微粒化の基礎と基本用語辞典」 日本液体微粒化学会／編 ２００１年１１月発行 森北出版株式会社 参照）。   Here, the fragmentation length of the fuel spray generally refers to the distance required for the fuel injected at high pressure to atomize into droplets, but here the vaporization rate is low in a cold region, for example, and the liquid The region where the fuel cannot complete evaporation and the droplets exist at high density just below the nozzle hole of the fuel injection valve is broadly included as the splitting length of the spray (“Atomization Technology: Basics of atomization and basic terminology dictionary) ”Japan Liquid Atomization Society / Edition, November 2001, see Morikita Publishing Co., Ltd.).

図５は本実施形態におけるＥＣＵ１３での制御フローを示す。以下、本制御フローに従って説明する。
まずステップ１（図にはＳ１と記す。以下同様）では、クランク角センサ１４、アクセル開度センサ１５等からの信号に基づき、機関の回転速度、負荷等を検出する。
次にステップ２では、上記機関の回転速度、負荷等の運転条件に基づいた燃料噴射タイミング、燃料噴射量及び点火時期等の制御パラメータを予め記憶させておいたテーブルより読み込む。ここで、これらテーブルに従った上記制御パラメータの設定により、機関負荷・回転速度に応じた燃焼モードの切り換えが行われる。図２に示すように、成層燃焼では燃料噴射方向の内側キャビティ３ａと外側キャビティ３ｂとの切り換え、高負荷・高回転領域（図２の領域ｃ）では均質燃焼を実施する。 FIG. 5 shows a control flow in the ECU 13 in this embodiment. Hereinafter, it demonstrates according to this control flow.
First, in step 1 (denoted as S1 in the figure, the same applies hereinafter), the engine speed, load, and the like are detected based on signals from the crank angle sensor 14, the accelerator opening sensor 15, and the like.
Next, in step 2, control parameters such as fuel injection timing, fuel injection amount, and ignition timing based on operating conditions such as engine speed and load are read from a previously stored table. Here, the combustion mode is switched according to the engine load and the rotational speed by setting the control parameters according to these tables. As shown in FIG. 2, in stratified combustion, switching between the inner cavity 3a and the outer cavity 3b in the fuel injection direction is performed, and homogeneous combustion is performed in a high load / high rotation region (region c in FIG. 2).

ステップ３では、燃料噴霧の***長さＬｂを、吸気圧力、吸気温度、噴射圧力と燃料温度からなる関数により算出し、あらかじめ記憶されている燃料の噴射点（燃料噴射弁１１の噴孔）から燃料噴霧が内側キャビティ３ａ壁面に衝突する点までの軸方向距離Ｈｂを参照する。
ここで、前記噴霧の噴射点から衝突点までの軸方向距離は、燃料噴射期間中に変化するが、該燃料噴射期間中に***長さＬｂ以下となるかが判ればよいので、燃料噴射期間中にピストン３が最も上昇して最短となるときの値に設定すればよい（燃料噴射期間が圧縮上死点前で終了するときは噴射終了タイミング、燃料噴射期間が圧縮上死点を含む場合には、圧縮上死点で最短となる）。
次に、ステップ４では、上記燃料噴霧の***長さＬｂと噴射点から噴霧が衝突する点までの軸方向距離Ｈｂを比較し、ステップ５にてＬｂよりもＨｂが大きいと判定されたときは、燃料の燃料噴霧が液柱（液膜）状態でピストン壁面に衝突することはないと判断されるのでステップ８に進み、上記各制御パラメータを通常状態での設定とした運転を行う。
ステップ４で燃料噴霧の***長さＬｂがＨｂより大きいと判定された場合は、ステップ５に進み、内側キャビティ３ａを指向した燃料噴射を行う運転領域（図２の領域ａ）か否かを判断する。 In step 3, the fuel spray split length Lb is calculated by a function consisting of the intake pressure, the intake temperature, the injection pressure and the fuel temperature, and the fuel injection point (the injection hole of the fuel injection valve 11) stored in advance is calculated. Reference is made to the axial distance Hb to the point where the fuel spray collides with the wall surface of the inner cavity 3a.
Here, although the axial distance from the spray injection point to the collision point changes during the fuel injection period, it is only necessary to know whether it becomes the split length Lb or less during the fuel injection period. What is necessary is just to set to the value when the piston 3 rises to the shortest and becomes the shortest (when the fuel injection period ends before the compression top dead center, when the fuel injection period includes the compression top dead center Is the shortest at compression top dead center).
Next, in Step 4, the split length Lb of the fuel spray is compared with the axial distance Hb from the injection point to the point where the spray collides, and when it is determined in Step 5 that Hb is larger than Lb. Then, since it is determined that the fuel spray of the fuel does not collide with the piston wall surface in the liquid column (liquid film) state, the process proceeds to step 8 to perform the operation with the above control parameters set in the normal state.
If it is determined in step 4 that the fuel spray split length Lb is greater than Hb, the process proceeds to step 5 to determine whether or not the operation region (region a in FIG. 2) in which fuel injection is directed to the inner cavity 3a. To do.

ステップ５で、燃料噴射を内側キャビティ３ａへ指向させる運転領域ａと判断された場合は、ステップ７に進み、通常は内側キャビティ３ａを指向するべき運転領域ａにおいても、外側キャビティ３ｂを指向した燃料噴射を行って、主として外側キャビティ３ｂ内で成層燃焼が行われるようにする。
ただし、外側キャビティ３ｂに指向させて噴射後に直接火花点火を行う第１の成層燃焼モードを適用している場合においては、その燃焼特性上、噴射時期から点火時期までの混合時間が短いことから、キャビティ底面に形成された過濃混合気がリーン化する前に燃焼してしまいスモークが排出されやすくなることがある。このため、ピストン３を介して形成された混合気に火花点火を行う第２の成層燃焼モードに切り変えてもよい{後述の図６（Ａ）に点火時期を点線で示す}。 If it is determined in step 5 that the operation region a directs the fuel injection to the inner cavity 3a, the process proceeds to step 7, and the fuel directed to the outer cavity 3b also in the operation region a that should normally direct the inner cavity 3a. Injection is performed so that stratified combustion is mainly performed in the outer cavity 3b.
However, in the case of applying the first stratified combustion mode in which spark ignition is performed directly after injection directed to the outer cavity 3b, the mixing time from the injection timing to the ignition timing is short due to its combustion characteristics, The rich air-fuel mixture formed on the bottom surface of the cavity may burn before being leaned, and smoke may be easily discharged. Therefore, the air-fuel mixture formed via the piston 3 may be switched to the second stratified combustion mode in which spark ignition is performed (ignition timing is indicated by a dotted line in FIG. 6A described later).

上記第２の成層燃焼モードでは、噴霧が内側キャビティ３ａに衝突し、点火プラグ１２まで巻き上がるまでの時間が確保でき、噴射量の少ない低負荷においては点火プラグ１２が燻りにくい効果が得られる。
また、燃料噴霧が内側キャビティ３ａのエッジ部分に干渉するとスモークが排出される要因となり、効果が半減するため、噴射期間中もしくは噴射終了後の噴霧が内側キャビティ３ａのエッジ部分に干渉することなく全燃料を外側キャビティ３ｂに指向させるようにする。このようにすれば、外側キャビティ３ｂのエッジ部に混合気が集中して衝突することがなく、過濃混合気すなわちスモークの生成が回避できる。 In the second stratified combustion mode, the time until the spray collides with the inner cavity 3a and winds up to the spark plug 12 can be secured, and the spark plug 12 is less likely to be swung at a low load with a small injection amount.
Further, if the fuel spray interferes with the edge portion of the inner cavity 3a, smoke is discharged, and the effect is reduced by half. Therefore, the spray during the injection period or after the completion of the injection does not interfere with the edge portion of the inner cavity 3a. The fuel is directed to the outer cavity 3b. In this way, the air-fuel mixture does not concentrate and collide with the edge portion of the outer cavity 3b, and the generation of the rich air-fuel mixture, that is, smoke can be avoided.

図６に燃料噴射パターンもしくは、燃料噴射弁仕様の違いによる設定点の変化を示す。
同図（Ａ）は、通常は内側キャビティ３ａを指向させる低負荷領域ａで、噴射タイミングだけで外側キャビティ３ｂに指向させた燃料噴射に切り換える燃料噴射パターンの基本的な形態を示し、燃料噴射タイミングを進角させ、燃料噴射終了近傍で点火を行う。
このように、低負荷（小噴射量）領域で、外側キャビティ３ｂに指向させた燃料噴射を行う場合は、点火プラグ周りの混合気が希薄となり、また、点火時期も噴射時期の進角に伴って進角させることとなるので点火時期での筒内圧力が低くなり、失火してしまう可能性がある。 FIG. 6 shows changes in the set points due to differences in fuel injection patterns or fuel injection valve specifications.
FIG. 6A shows a basic form of a fuel injection pattern in which the fuel injection pattern is switched to the fuel injection directed to the outer cavity 3b only by the injection timing in the low load region a in which the inner cavity 3a is normally directed. Is advanced to ignite near the end of fuel injection.
Thus, when fuel injection directed to the outer cavity 3b is performed in the low load (small injection amount) region, the air-fuel mixture around the spark plug becomes lean, and the ignition timing also increases with advance of the injection timing. Therefore, the cylinder pressure at the ignition timing is lowered and there is a possibility of misfire.

そこで、同図（Ｂ）に示すように、１行程で２度噴射する分割噴射とし、２度目の噴射で点火プラグ近傍へ少量の燃料噴射を行うようにすると、２度目に噴射された燃料に火花点火を行うため、任意のタイミングでプラグギャップに可燃混合気を供給できるため、噴射時期の進角量に依存することなく、所望の（筒内圧力が高い状態での）点火時期の設定が可能となり、着火性が高められ、安定した燃焼を確保でき、燃費の良い運転が可能となる。   Therefore, as shown in FIG. 5B, when the divided injection is performed twice in one stroke and a small amount of fuel is injected near the spark plug in the second injection, the fuel injected in the second time is changed. Since spark ignition is performed, the combustible air-fuel mixture can be supplied to the plug gap at any timing, so that the desired ignition timing (with a high in-cylinder pressure) can be set without depending on the advance amount of the injection timing. Thus, ignitability is enhanced, stable combustion can be ensured, and fuel-efficient driving is possible.

同図（Ｃ）は、燃料噴射弁１１として、ピエゾ式で針弁が本体から外側に突出してリフトする外開きのリフト量可変なタイプを用いた場合を示し、通常は内側キャビティ３ａを指向させる低負荷領域ａで外側キャビティ３ｂに指向させた燃料噴射に切り換えるときに、燃料噴射弁１１の針弁を低リフトとし、噴射期間を延ばすようにする。
このようにすれば、噴射期間の大部分を外側キャビティ３ｂに指向させて、外側キャビティ３ｂ内での成層燃焼を行うことができる。また、噴射期間が延びるので噴射終了近傍に設定される点火時期を過度に進角させる必要がなく、安定した燃焼を確保でき、燃費の良い運転が可能となる。また、燃料噴射弁が外開きタイプであるため、低リフト化することで、液膜厚さを低減することができ、これにより微粒化が進み、より均質な混合気を形成できる効果もある。 FIG. 6C shows a case where a piezo type and a needle valve that protrudes outward from the main body and has a variable lift amount is used as the fuel injection valve 11 and is usually directed to the inner cavity 3a. When switching to fuel injection directed to the outer cavity 3b in the low load region a, the needle valve of the fuel injection valve 11 is set to a low lift so that the injection period is extended.
In this way, most of the injection period can be directed to the outer cavity 3b, and stratified combustion can be performed in the outer cavity 3b. Further, since the injection period is extended, it is not necessary to advance the ignition timing set in the vicinity of the end of injection excessively, stable combustion can be ensured, and driving with good fuel consumption is possible. In addition, since the fuel injection valve is of the outward opening type, it is possible to reduce the liquid film thickness by lowering the lift, which has the effect that atomization proceeds and a more homogeneous air-fuel mixture can be formed.

同図（Ｄ）は、燃料噴射弁１１として噴霧角可変なタイプを用いた場合を示し、噴射時期を変更することなく容易に外側キャビティ３ｂを指向した燃料噴射が可能となるため、点火時期が最適となる噴射タイミングにて外側キャビティ３ｂへ指向した燃料噴射が可能となる。特に燃料噴射弁として渦巻き噴射弁とした場合、燃料噴霧角を大きくする手段として、燃圧を大きくすることにより、噴射弁の構造を複雑化することなく噴霧角の変更が可能となる。   FIG. 4D shows a case where a spray angle variable type is used as the fuel injection valve 11, and fuel injection directed to the outer cavity 3b can be easily performed without changing the injection timing. Fuel injection directed to the outer cavity 3b can be performed at the optimal injection timing. In particular, when a spiral injection valve is used as the fuel injection valve, the spray angle can be changed without complicating the structure of the injection valve by increasing the fuel pressure as means for increasing the fuel spray angle.

図５に戻って、ステップ５で外側キャビティ３ｂを指向する燃料噴射を行う運転領域ｂと判断された場合は、ステップ６に進み均質燃焼に切り換えることとする。
なお、内側キャビティ３ａより外側キャビティ３ｂ底面を深い形状とした場合は、燃料噴霧の噴射点からピストンへの衝突点までの軸方向距離Ｈｂをより増大させることができ、かつ、キャビティ容積も増大するので、さらにスモーク低減効果が高められる。 Returning to FIG. 5, if it is determined in step 5 that the operation region b performs fuel injection directed to the outer cavity 3 b, the process proceeds to step 6 to switch to homogeneous combustion.
When the bottom surface of the outer cavity 3b is deeper than the inner cavity 3a, the axial distance Hb from the fuel spray injection point to the collision point with the piston can be further increased, and the cavity volume also increases. Therefore, the smoke reduction effect is further enhanced.

図７（Ａ）は、図６（Ａ）に示した成層燃焼状態でＬｂ＞Ｈｂの判定によって、噴射タイミングを進角させて、内側キャビティ３ａから外側キャビティ３ｂへ燃料噴射の指向を変えた場合の混合気分布の変化の様子を示し、図７（Ｂ）は、成層燃焼モードで外側キャビティ３ｂへの燃料噴射の指向が要求される領域ｂで、Ｌｂ＞Ｈｂと判定されたときに、均質燃焼へ切り換えたときの混合気分布の変化の様子を示す。   FIG. 7A shows a case where the fuel injection direction is changed from the inner cavity 3a to the outer cavity 3b by advancing the injection timing according to the determination of Lb> Hb in the stratified combustion state shown in FIG. 6A. 7B shows a state of the change in the air-fuel mixture distribution, and FIG. 7B shows a homogeneous region when it is determined that Lb> Hb in the region b where the direction of fuel injection to the outer cavity 3b is required in the stratified combustion mode. The change of the air-fuel mixture distribution when switching to combustion is shown.

また、図８は、図６（Ｃ）に示した成層燃焼状態でＬｂ＞Ｈｂの判定によって、針弁リフト量を小さくして、内側キャビティ３ａから外側キャビティ３ｂへ燃料噴射の指向を変えた場合の混合気分布の変化の様子を示し、図９は、図６（Ｄ）に示した成層燃焼状態でＬｂ＞Ｈｂの判定によって、噴霧角を広角にして、内側キャビティ３ａから外側キャビティ３ｂへ燃料噴射の指向を変えた場合の混合気分布の変化の様子を示す。   FIG. 8 shows a case where the direction of fuel injection is changed from the inner cavity 3a to the outer cavity 3b by reducing the needle valve lift amount by the determination of Lb> Hb in the stratified combustion state shown in FIG. FIG. 9 shows the fuel mixture from the inner cavity 3a to the outer cavity 3b with a wide spray angle by the determination of Lb> Hb in the stratified combustion state shown in FIG. 6 (D). The state of the mixture distribution change when the injection direction is changed is shown.

以上のように、本実施形態では、通常は図２に示すような運転負荷・回転に応じた各燃焼モードの最適点にて運転が実施されるが、燃料噴霧の***長さＬｂが噴射点から噴射された噴霧がピストンへ衝突する点までの軸方向距離Ｈｂよりもながい場合に、内側キャビティを指向した燃焼モードの場合は外側キャビティを指向した燃焼モードへ切り換えることとしている。   As described above, in the present embodiment, the operation is normally performed at the optimum point of each combustion mode corresponding to the operation load and rotation as shown in FIG. 2, but the fuel spray split length Lb is the injection point. In the case of the combustion mode directed to the inner cavity, the combustion mode directed to the outer cavity is switched to the combustion mode directed to the inner cavity when the spray sprayed from to the piston collides with the piston.

これにより、例えば高地での運転などや気象条件、ブレーキブースターなどの要求により初期吸入空気圧が低下した場合や、寒冷地などで燃料の気化率が低い条件など環境パラメータが変化した場合において、噴霧の***長さＬｂが増大し、霧化及び気化が不十分な燃料が直接ピストンボウルに衝突してしまうことで形成される過濃度混合気から生成されるスモークにより、点火プラグの燻ってしまう問題が回避できるため、環境パラメータの変化よらずに成層燃焼を実施することが可能となる。   As a result, when the initial intake air pressure drops due to high altitude driving, weather conditions, demands for brake boosters, etc., or when environmental parameters change such as conditions where the fuel vaporization rate is low in cold regions, etc. There is a problem that the spark plug is swung up by smoke generated from the over-concentrated mixture formed by the split length Lb increasing and fuel with insufficient atomization and vaporization directly colliding with the piston bowl. Since this can be avoided, stratified combustion can be performed without changing environmental parameters.

また、内側キャビティを利用した成層燃焼を行う場合と比較して、混合気のサイズが大きくなるため燃費は若干悪化するが、ポンピングロスを伴う均質燃焼に切り換える場合よりも燃費のよい成層燃焼が実現できることになる。
さらに、急加速や登坂走行を除く通常の高速走行や市街走行において使用頻度の高い低負荷・低回転速度の領域は内側キャビティを用いた成層燃焼により実施されることから、***長さＬｂの判定により成層運転領域が拡大できる効果は大きい。 Compared with stratified combustion using the inner cavity, the fuel economy is slightly worse because the mixture size is larger, but stratified combustion with better fuel efficiency than switching to homogeneous combustion with pumping loss is realized. It will be possible.
Furthermore, since the low load and low rotation speed regions that are frequently used in normal high-speed driving and city driving excluding sudden acceleration and climbing are performed by stratified combustion using the inner cavity, the split length Lb is determined. As a result, the effect of expanding the stratified operation region is great.

本発明の実施形態にかかる直噴火花点火式内燃機関の構成を示す図。The figure which shows the structure of the direct injection spark ignition type internal combustion engine concerning embodiment of this invention. 機関の負荷と回転速度による燃焼モード領域と、各領域での混合気分布を示す図。The figure which shows the combustion mode area | region by the load and rotation speed of an engine, and air-fuel mixture distribution in each area | region. 噴霧の***長さＬｂと噴射点から噴霧衝突点までの距離Ｈｂの関係を示す図。The figure which shows the relationship between the division | segmentation length Lb of spray, and the distance Hb from an injection point to a spray collision point. 吸気温度、吸気圧力、燃料噴射圧力、燃料温度が噴霧の***長さに与える影響を示す図。The figure which shows the influence which intake temperature, intake pressure, fuel-injection pressure, and fuel temperature have on the split length of spray. 実施形態の制御フローを示すフローチャート。The flowchart which shows the control flow of embodiment. 燃料噴射弁仕様の違いによる噴射時期と点火時期の設定の変化を示すタイムチャート。The time chart which shows the change of the setting of the injection timing and ignition timing by the difference in a fuel injection valve specification. 基本的な燃料噴射パターンにおける内側キャビティから外側キャビティへの成層燃焼へ切り換えた場合および外側キャビティでの成層燃焼から均質燃焼に切り換えた場合の混合気分布を示す図。The figure which shows the fuel-air mixture distribution at the time of switching to the stratified combustion from the inner side cavity to an outer side cavity in the basic fuel injection pattern, and when switching from the stratified combustion in the outer side cavity to homogeneous combustion. 燃料噴射弁のリフト量を変化させる燃料噴射パターンにおける内側キャビティから外側キャビティへの成層燃焼へ切り換えた場合および外側キャビティでの成層燃焼から均質燃焼に切り換えた場合の混合気分布を示す図。The figure which shows the air-fuel | gaseous mixture distribution at the time of switching to the stratified combustion from an inner cavity to an outer cavity in the fuel-injection pattern which changes the lift amount of a fuel injection valve, and when switching from the stratified combustion in an outer cavity to homogeneous combustion. 燃料噴射量の噴霧角を変化させる燃料噴射パターンにおける内側キャビティから外側キャビティへの成層燃焼へ切り換えた場合および外側キャビティでの成層燃焼から均質燃焼に切り換えた場合の混合気分布を示す図。The figure which shows the air-fuel | gaseous mixture distribution at the time of switching to the stratified combustion from an inner cavity to an outer cavity in the fuel injection pattern which changes the spray angle of fuel injection quantity, and when switching from the stratified combustion in an outer cavity to homogeneous combustion.

符号の説明Explanation of symbols

３ ピストン
３ａ 内側キャビティ
３ｂ 外側キャビティ
４ 燃焼室
１１ 燃料噴射弁
１２ 点火プラグ
１３ エンジンコントロールユニット（ＥＣＵ）
１４ クランク角センサ
１５ アクセル開度センサ 3 Piston 3a Inner cavity 3b Outer cavity 4 Combustion chamber 11 Fuel injection valve 12 Spark plug 13 Engine control unit (ECU)
14 Crank angle sensor 15 Accelerator opening sensor

Claims (11)

燃料噴射弁を燃焼室上面の略中央部に設置し、ピストン冠面に前記燃料噴射弁から噴射される燃料噴霧の中心軸と略同一中心軸となるような大径ボウル状の外側キャビティと、該外側キャビティに内包された小径ボウル状の内側キャビティとで構成される二重構造のピストンキャビティを設けると共に、燃料噴霧の***長さを判定する手段を設け、
燃料噴射期間中において、前記燃料噴射弁の噴孔から内側キャビティ壁面に衝突するまでの距離が燃料噴霧の***長さより大きい通常の状態では、成層燃焼を実施している運転状態の中で比較的低負荷運転領域では内側キャビティに指向させて燃料を噴射し、比較的高負荷運転領域においては外側キャビティに指向させて燃料を噴射する一方、
前記燃料噴射弁の先端から内側キャビティまでの距離が燃料噴霧の***長さ以下となったときは、前記通常状態では内側キャビティに指向させて燃料を噴射する負荷領域においても、外側キャビティに指向させて燃料を噴射するように、燃料噴射制御を切り換えることを特徴とする直噴火花点火式内燃機関の制御装置。 A fuel injection valve is installed at a substantially central portion of the upper surface of the combustion chamber, and a large-diameter bowl-shaped outer cavity having a central axis substantially the same as the central axis of fuel spray injected from the fuel injection valve onto the piston crown surface; A double-structured piston cavity composed of a small-diameter bowl-shaped inner cavity enclosed in the outer cavity, and means for determining the fuel spray split length;
During the fuel injection period, in a normal state where the distance from the injection hole of the fuel injection valve to the inner cavity wall surface is larger than the split length of the fuel spray, the operation state in which stratified combustion is performed is relatively In the low load operation region, the fuel is injected toward the inner cavity, and in the relatively high load operation region, the fuel is injected toward the outer cavity,
When the distance from the tip of the fuel injection valve to the inner cavity is equal to or less than the split length of the fuel spray, in the normal state, the fuel is directed to the outer cavity even in the load region where fuel is injected by injecting the fuel into the inner cavity. A control apparatus for a direct injection spark ignition type internal combustion engine, wherein the fuel injection control is switched so as to inject fuel. 前記燃料噴霧の***長さによる判定によって、外側キャビティに指向させて燃料を噴射する場合、噴射期間中もしくは噴射終了後の燃料噴霧が内側キャビティエッジ部に干渉することなく、全燃料が外側キャビティへ指向するように燃料噴射制御することを特徴とする請求項１に記載の直噴火花点火式内燃機関の制御装置。   When fuel is injected toward the outer cavity according to the determination based on the splitting length of the fuel spray, the fuel spray during the injection period or after the end of the injection does not interfere with the inner cavity edge portion, and all the fuel enters the outer cavity. 2. The control device for a direct-injection spark-ignition internal combustion engine according to claim 1, wherein the fuel injection is controlled so as to be directed. 前記燃料噴霧の***長さによる判定によって、外側キャビティに指向させて燃料を噴射する場合、１行程で２度の分割燃料噴射を行い、２度目に噴射された燃料に火花点火を行うことを特徴とする請求項１または請求項２に記載の直噴火花点火式内燃機関の制御装置。   When fuel is injected toward the outer cavity according to the determination based on the split length of the fuel spray, split fuel injection is performed twice in one stroke, and spark ignition is performed on the fuel injected the second time. The control apparatus for a direct-injection spark-ignition internal combustion engine according to claim 1 or 2. 前記通常の状態では噴射終了後の燃料噴霧に直接火花点火を行う第１の成層燃焼モードとし、前記燃料噴射弁の先端から内キャビティ底面までの距離が噴霧の***長さ以下となった場合、内側キャビティ底面を介して巻き上がった混合気に火花点火を行う第２の成層燃焼モードに切り換えることを特徴とする請求項１及び２に記載の直噴火花点火式内燃機関の制御装置。   In the normal state, when the first stratified combustion mode in which spark ignition is performed directly on the fuel spray after the end of injection, and the distance from the tip of the fuel injection valve to the bottom of the inner cavity is equal to or less than the split length of the spray, 3. The control device for a direct injection spark ignition type internal combustion engine according to claim 1 or 2, wherein the control is switched to a second stratified combustion mode in which spark ignition is performed on the air-fuel mixture rolled up through the bottom surface of the inner cavity. 前記内側キャビティに指向させる燃料噴射と、外側キャビティに指向させる燃料噴射との切り換えを、燃料噴射タイミングを変化させて行うことを特徴とする請求項１から請求項４のいずれか１つに記載の直噴火花点火式内燃機関の制御装置。   The fuel injection to be directed to the inner cavity and the fuel injection to be directed to the outer cavity are performed by changing the fuel injection timing. Control device for a direct injection spark ignition internal combustion engine. 前記内側キャビティに指向させる燃料噴射と、外側キャビティに指向させる燃料噴射との切り換えを、燃料噴霧角を変化させて行うことを特徴とする請求項１から請求項４のいずれか１つに記載の直噴火花点火式内燃機関の制御装置。   5. The fuel injection directed to the inner cavity and the fuel injection directed to the outer cavity are performed by changing a fuel spray angle. 6. Control device for a direct injection spark ignition internal combustion engine. 前記燃料噴射弁として渦巻き噴射弁を用い、燃圧を変化させることにより燃料噴霧角を変化させることを特徴とする請求項６に記載の直噴火花点火式内燃機関の制御装置。   7. The control device for a direct injection spark ignition type internal combustion engine according to claim 6, wherein a spiral injection valve is used as the fuel injection valve, and the fuel spray angle is changed by changing the fuel pressure. 前記燃料噴射弁が針弁のリフト量を可変な構造を有し、前記燃料噴霧の***長さの判定により、外側キャビティでの前記第１の成層燃焼モードを行う場合は、針弁のリフト量を低下させて燃料噴射期間を大きくすることを特徴とする請求項１〜請求項４のいずれか１つに記載の直噴火花点火式内燃機関の制御装置。   When the fuel injection valve has a structure in which the lift amount of the needle valve is variable and the first stratified combustion mode is performed in the outer cavity by determining the split length of the fuel spray, the lift amount of the needle valve The control apparatus for a direct injection spark ignition type internal combustion engine according to any one of claims 1 to 4, wherein the fuel injection period is increased by reducing the fuel injection period. 前記燃料噴射弁が、針弁が本体の外側に突出して開く外開きタイプであることを特徴とする請求項８記載の直噴火花点火式内燃機関の制御装置。   9. The control device for a direct injection spark ignition type internal combustion engine according to claim 8, wherein the fuel injection valve is an outward opening type in which a needle valve protrudes outward from the main body. 外側キャビティを内側キャビティより深く形成して、燃料噴射弁先端から外側キャビティ底面までの距離が、燃料噴射弁先端から内側キャビティ底面までの距離よりも長く形成してあることを特徴とする請求項１〜請求項９のいずれか１つに記載の直噴火花点火式内燃機関の制御装置。   The outer cavity is formed deeper than the inner cavity, and the distance from the fuel injection valve tip to the outer cavity bottom surface is longer than the distance from the fuel injection valve tip to the inner cavity bottom surface. The control apparatus for a direct-injection spark-ignition internal combustion engine according to any one of claims 9 to 9. 前記燃料噴射弁の先端から内側キャビティまでの距離が燃料噴霧の***長さ以下となったときに、前記通常状態では外側キャビティに指向させて燃料を噴射する負荷領域のときは、燃焼モードを成層燃焼から均質燃焼へ切り換えることを特徴とする請求項１〜請求項１０のいずれか１つに記載の直噴火花点火式内燃機関の制御装置。   When the distance from the tip of the fuel injection valve to the inner cavity is equal to or less than the split length of the fuel spray, the combustion mode is stratified in the normal state in the load region in which fuel is injected toward the outer cavity. The control device for a direct injection spark ignition type internal combustion engine according to any one of claims 1 to 10, wherein the combustion is switched from combustion to homogeneous combustion.
JP2005155679A 2005-05-27 2005-05-27 Controller for direct injection spark ignition type internal combustion engine Pending JP2006329117A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013113096A (en) * 2011-11-24 2013-06-10 Mitsubishi Heavy Ind Ltd Fuel injection device
JP2016128668A (en) * 2015-01-09 2016-07-14 マツダ株式会社 Combustion chamber structure of engine

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013113096A (en) * 2011-11-24 2013-06-10 Mitsubishi Heavy Ind Ltd Fuel injection device
JP2016128668A (en) * 2015-01-09 2016-07-14 マツダ株式会社 Combustion chamber structure of engine
CN105781713A (en) * 2015-01-09 2016-07-20 马自达汽车株式会社 Combustion chamber structure for engine

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