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JP3975517B2 - Fuel injection control device for in-cylinder direct injection spark ignition engine - Google Patents

Fuel injection control device for in-cylinder direct injection spark ignition engine Download PDF

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Publication number
JP3975517B2
JP3975517B2 JP24104997A JP24104997A JP3975517B2 JP 3975517 B2 JP3975517 B2 JP 3975517B2 JP 24104997 A JP24104997 A JP 24104997A JP 24104997 A JP24104997 A JP 24104997A JP 3975517 B2 JP3975517 B2 JP 3975517B2
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Prior art keywords
fuel
fuel injection
injection pulse
injection
mixture
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JPH1182030A (en
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保憲 岩切
康治 平谷
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Nissan Motor Co Ltd
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Nissan Motor Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/3011—Controlling fuel injection according to or using specific or several modes of combustion
    • F02D41/3017—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used
    • F02D41/3023—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used a mode being the stratified charge spark-ignited mode
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/12—Other methods of operation
    • F02B2075/125—Direct injection in the combustion chamber for spark ignition engines, i.e. not in pre-combustion chamber
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
    • F02B23/08—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition
    • F02B23/10—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition with separate admission of air and fuel into cylinder
    • F02B23/104—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition with separate admission of air and fuel into cylinder the injector being placed on a side position of the cylinder
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D2041/389—Controlling fuel injection of the high pressure type for injecting directly into the cylinder
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
    • F02D41/402—Multiple injections
    • 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

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combustion Methods Of Internal-Combustion Engines (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は、筒内直噴式火花点火エンジンの燃料噴射制御装置において、燃料を多段階に噴射して燃焼性を改善する技術に関するものである。
【０００２】
【従来の技術】
点火プラグの近傍に燃料を集める混合気の成層化をはかるため、シリンダ内に燃料噴射弁を臨ませ、シリンダ内に燃料を直接噴射するようにした筒内直接噴射式火花点火エンジンがある。
【０００３】
従来の筒内直接噴射式火花点火エンジンとして、特開平６−３１７１６１号公報に開示されたものや、例えば図１５〜図２０に示すようなものがある。
【０００４】
これについて説明すると、図１５に示すように、シリンダヘッドとピストン５の間に燃焼室１が画成される。燃焼室天井壁にはその中央部から燃料噴射弁６と点火プラグ７が燃焼室１の中央部に臨み、これらを囲むようにして２本の吸気バルブ８と２本の排気バルブ９が設けられる。
【０００５】
コントロールユニットは、図１８に示すように、同一サイクルにて噴射パルス幅Ｔを３回に分割して出力し、１回目の噴射パルス幅Ｔ1が２回目の噴射パルス幅Ｔ2より長く設定され、２回目の噴射パルス幅Ｔ2が３回目の噴射パルス幅Ｔ3より長く設定される。１回目の噴射パルス幅Ｔ1は吸気行程から圧縮行程の前半にかけて出力され、２回目の噴射パルス幅Ｔ2と３回目の噴射パルス幅Ｔ3は圧縮行程の後半に出力される。
【０００６】
この場合、図１５に示すように、吸気行程の後半から圧縮行程の前半にかけて１回目の噴射パルスによって噴射された燃料噴霧２は空気と混合して燃焼室１の広い範囲に分布する希薄混合気をつくる。この希薄混合気は図１６に示すように、圧縮行程の後半に２回目の噴射パルスによって噴射された燃料噴霧３と重なるとともに、図１７に示すように、３回目の噴射パルスによって噴射された燃料噴霧４と重なることにより、可燃混合比の混合気が点火プラグ７の近傍につくられる。
【０００７】
【発明が解決しようとする課題】
しかしながら、このような従来の筒内直接噴射式火花点火エンジンにおいて、多段噴射した燃料噴霧を重ね合わせて可燃混合比の混合気が点火プラグ７の近傍につくられるため、燃料噴射弁６を燃焼室１の中央部に臨ませ、圧縮行程にて燃料噴霧による混合気が安定的な形状を維持する必要があり、限られた条件でしか混合気の成層化がはかれないという問題点があった。
【０００８】
例えば図１９に示すように、燃焼室１にスワールが生起される場合、スワールの空気流動によって燃料噴霧が撹拌、分散され、点火プラグ７の近傍に着火可能な混合気を集めることができない。
【０００９】
図２０にスワールの流れ方向（図１９のＡ−Ａ線）に沿う断面における混合気濃度分布を示しているが、３回に分割された燃料噴射パルス信号によって噴射された燃料噴霧がつくる混合気が分散し、点火プラグ７の近傍に分布する混合気も可燃混合気濃度に達しない。
【００１０】
本発明は上記の問題点を鑑みてなされたものであり、筒内直噴式火花点火エンジンの燃料噴射制御装置において、燃料を多段階に噴射して燃焼性を改善することを目的とする。
【００１１】
【課題を解決するための手段】
請求項１に記載の筒内直噴式火花点火エンジンの燃料噴射制御装置は、シリンダ内の混合気に点火する点火プラグと、シリンダ内に燃料を噴射する燃料噴射弁と、燃料噴射弁を開弁させる燃料噴射パルス信号を出力する筒内直噴式火花点火エンジンの燃料噴射制御装置において、圧縮行程にて出力される燃料噴射パルス信号を複数に分割し、分割された燃料噴射パルス信号のうち１回目の燃料噴射パルス幅を２回目以降の燃料噴射パルス幅より長く設定し、前記分割された燃料噴射パルス幅の間の噴射パルス停止幅を、直後の燃料噴射パルス幅よりも短く設定し、燃料噴射弁から燃料噴霧を間欠的に噴射し、１回目の燃料噴射パルス信号によって噴射された燃料噴霧が点火プラグの近傍に可燃混合比の混合気をつくる構成とした。
【００１３】
請求項２に記載の筒内直噴式火花点火エンジンの燃料噴射制御装置は、請求項１に記載の発明において、前記シリンダ内にタンブルを生起するタンブル生起手段を備え、燃料噴射弁からタンブルの流れ方向に燃料を噴射する構成とした。
【００１４】
請求項３に記載の筒内直噴式火花点火エンジンの燃料噴射制御装置は、請求項１に記載の発明において、前記シリンダ内にスワールを生起するスワール生起手段を備え、燃料噴射弁からスワールの流れ方向に燃料を噴射する構成とした。
【００１５】
【発明の作用および効果】
請求項１に記載の筒内直噴式火花点火エンジンの燃料噴射制御装置において、圧縮行程にて分割された燃料噴射パルス信号のうち１回目の燃料噴射パルス幅を２回目以降の燃料噴射パルス幅より長く設定し、１回目の燃料噴射パルス信号によって噴射された燃料噴霧が点火プラグの近傍に可燃混合比の混合気をつくり、広い運転条件にわたって混合気の成層化がはかれ、燃料噴射弁の取付け位置等に対する制約を少なくする。
【００１６】
例えば同一サイクルにおける噴射パルス幅Ｔを３回に分割して出力する場合、１回目の噴射パルスによって噴射された燃料噴霧は、２回目、３回目の噴射パルスによって噴射された燃料噴霧に比べて燃焼室で拡散する期間が長いが、噴射量が多いために混合気塊が適度に拡散する。これにより、可燃混合比の混合気が点火時期を迎える点火プラグの近傍に到達し、混合気の成層化がはかれ、エミッションを改善するとともに、燃費の低減がはかれる。
【００１７】
２回目、３回目の噴射パルスによって噴射された燃料噴霧は、燃焼室で拡散する期間が次第に短くなるが、１回目の噴射パルスによって噴射された燃料噴霧に比べて噴射量が少ないため、混合気塊と空気との接触面積が増え、燃料噴霧の拡散が十分に行われ、可燃混合比の混合気が点火プラグの近傍に到達し、すす等の排出量を減らすことができる。
【００１８】
そして、同一サイクルにて分割された燃料噴射パルス幅に対してその間に設けられる噴射パルス停止幅が短くなるように設定し、燃料噴射弁から燃料噴霧を間欠的に噴射することにより、燃焼室において混合比が形成される領域を点火プラグの近傍の狭い範囲に限定することが可能となり、混合気を希薄化する成層燃焼領域を拡大して、エミッションを改善するとともに、燃費の低減がはかれる。
【００１９】
請求項２に記載の筒内直噴式火花点火エンジンの燃料噴射制御装置において、燃料噴射弁の燃料噴射方向が、タンブルの流れ方向に沿っているため、段階的に噴射された燃料噴霧はタンブルと共に旋回し、互いにほぼ連続した混合気塊を点火プラグの近傍につくり、燃焼室において混合気の成層化がはかれ、着火が確実に行われるとともに、燃焼性を高められる。
【００２０】
請求項３に記載の筒内直噴式火花点火エンジンの燃料噴射制御装置において、燃料噴射弁の燃料噴射方向が、スワールの流れ方向に沿っているため、段階的に噴射された燃料噴霧はスワールと共に旋回し、互いにほぼ連続した混合気塊を点火プラグの近傍につくり、燃焼室において混合気の成層化がはかれ、着火が確実に行われるとともに、燃焼性を高められる。
【００２１】
【発明の実施の形態】
以下、本発明の実施形態を添付図面に基づいて説明する。
【００２２】
図１に示すように、シリンダヘッドとピストン５の間に燃焼室１が画成される。点火プラグ７が燃焼室１の中央部に臨み、ペントルーフ型に傾斜する燃焼室天井壁には２本の吸気バルブ８と２本の排気バルブ９が点火プラグ７を挟むようにして互いに対向して設けられる。
【００２３】
燃焼室天井壁にはその側部から燃焼室１に臨む燃料噴射弁６が設けられる。燃料噴射弁６は各吸気バルブ８の側方で、かつ各吸気バルブ８の間に位置して燃焼室１に臨んでいる。
【００２４】
燃料噴射弁６から所定のタイミングで燃焼室１に噴射される燃料噴霧は、各吸気バルブ８が開かれるのに伴って吸気ポートからシリンダに吸入される空気と混合する。シリンダに形成された混合気はピストン５で圧縮された状態で点火プラグ７を介して燃料が着火燃焼する。燃焼したガスはピストン５を下降させてクランクシャフトを介して回転力を取り出した後、ピストン５が上昇する排気行程中に排気バルブ８が開かれるのに伴って各排気ポートから排出される。これらの各行程が連続して繰り返される。
【００２５】
本実施形態において、各吸気ポートに均等に分流してシリンダ内に流入する吸気流は、図中矢印で示すように、ピストン５の冠部上でシリンダ中心線と直交する軸を中心に旋回するタンブルを生起する。
【００２６】
燃料噴射弁６の燃料噴射方向はタンブルの吸気流れ方向と略同一方向に設定される。図３、図４に示すように、燃料噴射弁６から噴射される燃料噴霧は、燃料噴射弁６の中心線Ｉを中心とする円錐状に拡がる。
【００２７】
燃料噴射弁６はその開弁時期（燃料噴射時期）と開弁期間（燃料噴射量）が図示しないコントロールユニットにより運転状態に応じて制御される。コントロールユニットは、演算された燃料噴射量に対応するパルス信号を燃料噴射弁６の駆動回路（図示せず）に出力する。これに伴って、駆動回路からパルス信号に対応する駆動電流が燃料噴射弁６のアクチュエータに送られ、燃料噴射弁６のニードルがリフトして噴口を開弁する。燃料噴射パルスが長いほど、燃料噴射弁６の開弁期間が長くなり、燃料噴射量が増えるようになっている。
【００２８】
コントロールユニットは、所定の均質燃焼領域で燃料噴射時期をピストン５が下降する吸気行程に設定するとともに、空燃比を理論空燃比を中心とした狭い範囲に収める。一方、所定の成層燃焼領域で燃料噴射時期をピストン５が上昇する圧縮行程の後半に設定するとともに、空燃比を理論空燃比より希薄側に制御する。
【００２９】
コントロールユニットは、成層燃焼領域では、同一サイクルで出力されるパルス信号を複数に分割し、燃料噴射弁６からの燃料噴射を多段階に行う構成とする。そして同一サイクルにて複数回に分割された燃料噴射パルス幅が噴射後期になるのにしたがって次第に短くなるように設定される。すなわち、図５に示すように、噴射パルス幅Ｔを３回に分割して出力する場合、１回目の噴射パルス幅Ｔ1が２回目の噴射パルス幅Ｔ2より長く設定され、２回目の噴射パルス幅Ｔ2が３回目の噴射パルス幅Ｔ3より長く設定される。
【００３０】
さらに、同一サイクルにて分割された各燃料噴射パルス幅に対してその間に設けられる噴射パルス停止幅が短くなるように設定され、同一サイクルにて燃料噴射弁６から燃料噴霧がその途中で途絶えることなく間欠的に噴射される構成とする。すなわち、図５に示すように、噴射パルス幅を３回に分割して出力する場合、１回目のパルス停止幅Ｉ1が２回目の噴射パルス幅Ｔ2より短く設定され、２回目のパルス停止幅Ｉ2が３回目の噴射パルス幅Ｔ3より短く設定される。
【００３１】
図６はタンブルの流れ方向（図２のＡ−Ａ線）に沿う断面における混合気濃度分布を示している。３回に分割された燃料噴射パルス信号によって噴射された燃料噴霧がつくる混合気が分布する。
【００３２】
図６において、同一ストロークにて分割された３つの燃料噴射パルス信号によって噴射された燃料噴霧はいずれも独立して可燃混合気濃度に収まる混合気をつくり、１回目の燃料噴射パルス信号によって噴射された燃料噴霧が点火時期を迎える点火プラグ７の近傍に可燃混合気濃度に収まる混合気をつくる構成とする。
【００３３】
図８のフローチャートは燃料噴射パルス信号を制御するルーチンを示しており、コントロールユニットにおいて一定周期毎に実行される。
【００３４】
これについて説明すると、まずステップ１にて、エンジン回転数、エンジン負荷等の運転条件を検出する。
【００３５】
続いてステップ２に進んで、エンジン回転数、エンジン負荷等の検出値に応じて燃料噴射パルス幅Ｔを算出する。
【００３６】
続いてステップ３に進んで、燃料噴射パルス幅Ｔを副数回に分割する。これは、図７に示すように、噴射パルス幅を３回に分割して出力する場合、１回目の噴射パルス幅Ｔ1と２回目の噴射パルス幅Ｔ2および３回目の噴射パルス幅Ｔ3による各噴射量の合計値Ｔ1＋Ｔ2＋Ｔ3が噴射パルス幅Ｔになるように算出される。
【００３７】
続いてステップ４に進んで、エンジン回転数、エンジン負荷等の検出値に応じた噴射開始時期もしくは噴射終了時期から、分割された各噴射パルス信号を出力する噴射開始クランク角度を算出する。
【００３８】
続いてステップ５に進んで、算出された噴射開始クランク角度が来るとコントロールユニットから駆動回路にパルス信号を出力して燃料噴射弁６を開弁させ、本ルーチンを終了する。
【００３９】
以上のように構成され、次に作用について説明する。
【００４０】
エンジン３０の負荷または回転数が所定値以下の成層燃焼領域で、図１、図２に示すように、ピストン５が上昇する圧縮行程の後半に燃料噴射弁６から燃料が多段階に噴射される。吸気行程でシリンダ内に生起されたタンブルは圧縮行程の後半まで持続しているため、燃料噴射弁６から噴射された燃料噴霧はタンブルと共に旋回する。
【００４１】
燃料噴射弁６から燃料が多段階に噴射されることにより、燃料噴射弁６から燃料が連続的に噴射される場合に比べて、混合気の燃料濃度が高くなり過ぎることが抑えられ、すす等の排出量を減らすことができる。
【００４２】
同一サイクルにおける噴射パルス信号を３回に分割して出力する。この場合、１回目の噴射パルス信号によって噴射された燃料噴霧２は、２回目、３回目の噴射パルス信号によって噴射された燃料噴霧３，４に比べて燃焼室１でタンブルと共に旋回する期間が長いが、噴射量が多いために混合気塊が適度に拡散し、可燃混合比の混合気が点火時期を迎える点火プラグ７の近傍に到達する。
【００４３】
２回目、３回目の噴射パルス信号によって噴射された燃料噴霧３，４は、タンブルと共に拡散する期間が短いが、１回目の噴射パルス信号によって噴射された燃料噴霧に比べて噴射量が少ないため、混合気塊と空気との接触面積が増え、燃料噴霧の拡散が十分に行われ、可燃混合比の混合気が分布し、すす等の排出量を減らすことができる。
【００４４】
燃料噴射弁６の燃料噴射方向が、タンブルの流れ方向に沿っているため、１回目、２回目、３回目の噴射パルス信号によって噴射された燃料噴霧２，３，４はタンブルと共に旋回する。図６に混合気濃度の分布を示すように、互いにほぼ連続した混合気塊を点火プラグ７の近傍につくり、燃焼室１において混合気の成層化がはかれ、着火が確実に行われるとともに、燃焼性を高められる。
【００４５】
また、同一サイクルにおける噴射パルス幅Ｔを複数に分割して出力し、１回目の噴射パルス幅を、２回目、３回目の噴射パルス幅より長く設定する場合に比べて、混合気の外縁部が拡散して可燃混合比を超えて希薄化することが抑えられ、未燃焼ＨＣ量を減らすことができる。
【００４６】
１回目のパルス停止幅Ｉ1が２回目の噴射パルス幅Ｔ2より短く設定され、２回目のパルス停止幅Ｉ2が３回目の噴射パルス幅Ｔ3より短く設定されることにより、燃焼室１において混合比が形成される領域を点火プラグ７の近傍の狭い範囲に限定することが可能となり、混合気を希薄化する成層燃焼領域を拡大して、エミッションを改善するとともに、燃費の低減がはかれる。
【００４７】
次に、図９〜図１４に示す実施形態について説明する。なお、図１〜図６との対応部分には同一符号を付す。
【００４８】
本実施形態において、吸気通路に一方の吸気ポートの吸気流速を高めるスワールコントロールバルブを備え、図１０に矢印で示すように、ピストン５の冠部上でシリンダ中心線を軸として旋回するスワールを生起するようになっている。
【００４９】
燃料噴射弁６の燃料噴射方向はスワールの吸気流れ方向と略同一方向に設定される。すなわち、図１１、図１２に示すように、燃料噴射弁６から噴射される燃料噴霧は、燃料噴射弁６の中心線Ｉに対してスワールの旋回方向に傾斜した軸を中心に円錐状に拡がる。
【００５０】
コントロールユニットは、成層燃焼領域において、同一サイクルにてパルス信号を副数に分割して出力し、燃料噴射弁６からの燃料噴射を多段階に行う構成とする。
【００５１】
同一サイクルにて複数回に分割された燃料噴射パルス幅が噴射後期になるのにしたがって次第に短くなるように設定される。すなわち、図１３に示すように、噴射パルス幅Ｔを３回に分割して出力する場合、１回目の噴射パルス幅Ｔ1が２回目の噴射パルス幅Ｔ2より長く設定され、２回目の噴射パルス幅Ｔ2が３回目の噴射パルス幅Ｔ3より長く設定される。
【００５２】
さらに、同一サイクルにて分割された各燃料噴射パルス幅に対してその間に設けられる噴射パルス停止幅が短くなるように設定され、同一サイクルにて燃料噴射弁６から燃料噴霧がその途中で途絶えることなく、間欠的に噴射される構成とする。すなわち、図１３に示すように、噴射パルス幅を３回に分割して出力する場合、１回目のパルス停止幅Ｉ1が２回目の噴射パルス幅Ｔ2より短く設定され、２回目のパルス停止幅Ｉ2が３回目の噴射パルス幅Ｔ3より短く設定される。
【００５３】
図１４はスワールの流れ方向（図２のＡ−Ａ線）に沿う断面における混合気濃度分布を示している。３回に分割された燃料噴射パルス信号によって噴射された燃料噴霧がつくる混合気が分布する。
【００５４】
図１４において、同一ストロークにて分割された３つの燃料噴射パルス信号によって噴射された燃料噴霧はいずれも独立して可燃混合気濃度に収まる混合気をつくり、１回目の燃料噴射パルス信号によって噴射された燃料噴霧が点火時期を迎える点火プラグ７の近傍に可燃混合気濃度に収まる混合気をつくる構成とする。
【００５５】
以上のように構成され、次に作用について説明する。
【００５６】
エンジン３０の負荷または回転数が所定値以下の成層燃焼領域で、図９、図１０に示すように、ピストン５が上昇する圧縮行程の後半に燃料噴射弁６から燃料が多段階に噴射される。吸気行程でシリンダ内に生起されたスワールは圧縮行程の後半まで持続しているため、燃料噴射弁６から噴射された燃料噴霧はスワールと共に旋回する。
【００５７】
燃料噴射弁６から燃料が多段階に噴射されることにより、燃料噴射弁６から燃料が連続的に噴射される場合に比べて、混合気の燃料濃度が高くなり過ぎることが抑えられ、すす等の排出量を減らすことができる。
【００５８】
同一サイクルにおける噴射パルス信号を３回に分割して出力する。この場合、１回目の噴射パルス信号によって噴射された燃料噴霧２は、２回目、３回目の噴射パルス信号によって噴射された燃料噴霧３，４に比べて燃焼室１でスワールと共に旋回する期間が長いが、噴射量が多いために混合気塊が適度に拡散し、可燃混合比の混合気が点火時期を迎える点火プラグ７の近傍に到達する。
【００５９】
２回目、３回目の噴射パルス信号によって噴射された燃料噴霧３，４は、スワールと共に拡散する期間が短いが、１回目の噴射パルス信号によって噴射された燃料噴霧に比べて噴射量が少ないため、混合気塊と空気との接触面積が増え、燃料噴霧の拡散が十分に行われ、可燃混合比の混合気が分布し、すす等の排出量を減らすことができる。
【００６０】
燃料噴射弁６の燃料噴射方向が、スワールの流れ方向に沿っているため、１回目、２回目、３回目の噴射パルス信号によって噴射された燃料噴霧２，３，４はスワールと共に旋回する。図６に混合気濃度の分布を示すように、互いにほぼ連続した混合気塊を点火プラグ７の近傍につくり、燃焼室１において混合気の成層化がはかれ、着火が確実に行われるとともに、燃焼性を高められる。
【００６１】
また、同一サイクルにおける噴射パルス幅Ｔを複数に分割して出力し、１回目の噴射パルス幅を、２回目、３回目の噴射パルス幅より長く設定する場合に比べて、混合気の外縁部が拡散して可燃混合比を超えて希薄化することが抑えられ、未燃焼ＨＣ量を減らすことができる。
【００６２】
１回目のパルス停止幅Ｉ1が２回目の噴射パルス幅Ｔ2より短く設定され、２回目のパルス停止幅Ｉ2が３回目の噴射パルス幅Ｔ3より短く設定されることにより、燃焼室１において混合比が形成される領域を点火プラグ７の近傍の狭い範囲に限定することが可能となり、混合気を希薄化する成層燃焼領域を拡大して、エミッションを改善するとともに、燃費の低減がはかれる。
【図面の簡単な説明】
【図１】本発明の実施形態を示す燃焼室の断面図。
【図２】同じく燃焼室の平面図。
【図３】同じく燃料噴霧の形態を示す正面図。
【図４】同じく燃料噴霧の形態を示す平面図。
【図５】同じく燃料噴射パルス信号を示す図。
【図６】同じく混合気濃度の分布図。
【図７】同じく燃料噴射パルス幅の算出方法を示す図。
【図８】同じく燃料噴射弁の制御内容を示すフローチャート。
【図９】他の実施形態を示す燃焼室の断面図。
【図１０】同じく燃焼室の平面図。
【図１１】同じく燃料噴霧の形態を示す正面図。
【図１２】同じく燃料噴霧の形態を示す平面図。
【図１３】同じく燃料噴射パルス信号を示す図。
【図１４】同じく混合気濃度の分布図。
【図１５】従来例を示す燃焼室の断面図。
【図１６】同じく燃焼室の断面図。
【図１７】同じく燃焼室の断面図。
【図１８】同じく燃料噴射パルス信号を示す図。
【図１９】同じく燃焼室の平面図。
【図２０】同じく混合気濃度の分布図。
【符号の説明】
１ 燃焼室
５ ピストン
６ 燃料噴射弁
７ 点火プラグ
８ 吸気バルブ
９ 排気バルブ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for improving combustibility by injecting fuel in multiple stages in a fuel injection control device for a direct injection type spark ignition engine.
[0002]
[Prior art]
In order to achieve stratification of an air-fuel mixture that collects fuel in the vicinity of a spark plug, there is an in-cylinder direct injection spark ignition engine in which a fuel injection valve faces a cylinder and fuel is directly injected into the cylinder.
[0003]
Conventional in-cylinder direct injection spark ignition engines include those disclosed in Japanese Patent Application Laid-Open No. 6-317161 and those shown in FIGS. 15 to 20, for example.
[0004]
This will be described. As shown in FIG. 15, the combustion chamber 1 is defined between the cylinder head and the piston 5. A fuel injection valve 6 and a spark plug 7 face the center of the combustion chamber 1 from the center of the ceiling wall of the combustion chamber, and two intake valves 8 and two exhaust valves 9 are provided so as to surround them.
[0005]
As shown in FIG. 18, the control unit divides and outputs the injection pulse width T three times in the same cycle, and the first injection pulse width T 1 is set longer than the second injection pulse width T 2. The second injection pulse width T 2 is set longer than the third injection pulse width T 3 . The first injection pulse width T 1 is output from the intake stroke to the first half of the compression stroke, and the second injection pulse width T 2 and the third injection pulse width T 3 are output in the second half of the compression stroke.
[0006]
In this case, as shown in FIG. 15, the fuel spray 2 injected by the first injection pulse from the second half of the intake stroke to the first half of the compression stroke is mixed with air and distributed in a wide range of the combustion chamber 1. Make. This lean air-fuel mixture overlaps with the fuel spray 3 injected by the second injection pulse in the latter half of the compression stroke as shown in FIG. 16, and the fuel injected by the third injection pulse as shown in FIG. By overlapping with the spray 4, an air-fuel mixture with a combustible mixture ratio is created in the vicinity of the spark plug 7.
[0007]
[Problems to be solved by the invention]
However, in such a conventional in-cylinder direct injection spark ignition engine, the fuel injection valve 6 is connected to the combustion chamber because a fuel mixture having a combustible mixture ratio is created in the vicinity of the spark plug 7 by superimposing the multi-stage injected fuel sprays. There is a problem that the air-fuel mixture by fuel spray needs to maintain a stable shape in the compression stroke, and the air-fuel mixture is stratified only under limited conditions. .
[0008]
For example, as shown in FIG. 19, when a swirl is generated in the combustion chamber 1, the fuel spray is stirred and dispersed by the air flow of the swirl, and an ignitable mixture cannot be collected in the vicinity of the spark plug 7.
[0009]
FIG. 20 shows an air-fuel mixture concentration distribution in a cross section along the swirl flow direction (A-A line in FIG. 19). The air-fuel mixture produced by the fuel spray injected by the fuel injection pulse signal divided three times is shown. And the air-fuel mixture distributed near the spark plug 7 does not reach the combustible air-fuel mixture concentration.
[0010]
The present invention has been made in view of the above problems, and an object of the present invention is to improve the combustibility by injecting fuel in multiple stages in a fuel injection control device of a direct injection spark ignition engine.
[0011]
[Means for Solving the Problems]
A fuel injection control device for an in-cylinder direct injection spark ignition engine according to claim 1, wherein an ignition plug for igniting an air-fuel mixture in a cylinder, a fuel injection valve for injecting fuel into the cylinder, and a fuel injection valve are opened. In a fuel injection control device for a direct injection type spark ignition engine that outputs a fuel injection pulse signal to be generated, the fuel injection pulse signal output in the compression stroke is divided into a plurality of times, and the first of the divided fuel injection pulse signals The fuel injection pulse width is set longer than the second and subsequent fuel injection pulse widths, the injection pulse stop width between the divided fuel injection pulse widths is set shorter than the immediately following fuel injection pulse width, and fuel injection is performed. The fuel spray is intermittently injected from the valve, and the fuel spray injected by the first fuel injection pulse signal creates a mixture with a combustible mixture ratio in the vicinity of the spark plug.
[0013]
According to a second aspect of the present invention, there is provided a fuel injection control device for a cylinder direct injection spark ignition engine according to the first aspect , comprising tumble generating means for generating a tumble in the cylinder, wherein the flow of the tumble from the fuel injection valve. The fuel was injected in the direction.
[0014]
According to a third aspect of the present invention, there is provided a fuel injection control device for an in-cylinder direct injection spark ignition engine according to the first aspect , further comprising swirl generating means for generating a swirl in the cylinder, and a flow of swirl from the fuel injection valve. The fuel was injected in the direction.
[0015]
Operation and effect of the invention
2. The fuel injection control apparatus for a direct injection type spark ignition engine according to claim 1, wherein the first fuel injection pulse width of the fuel injection pulse signals divided in the compression stroke is determined from the second and subsequent fuel injection pulse widths. The fuel spray injected by the first fuel injection pulse signal creates a mixture with a combustible mixture ratio in the vicinity of the spark plug, stratifies the mixture over a wide range of operating conditions, and installs the fuel injection valve Reduce restrictions on position, etc.
[0016]
For example, when the injection pulse width T in the same cycle is divided into three times and output, the fuel spray injected by the first injection pulse burns compared to the fuel spray injected by the second and third injection pulses. Although the period of diffusion in the chamber is long, the air-fuel mixture diffuses moderately due to the large injection amount. As a result, the air-fuel mixture having a combustible mixture ratio reaches the vicinity of the spark plug that reaches the ignition timing, and the air-fuel mixture is stratified to improve emissions and reduce fuel consumption.
[0017]
The fuel spray injected by the second and third injection pulses gradually has a shorter diffusion period in the combustion chamber, but has a smaller injection amount than the fuel spray injected by the first injection pulse. The contact area between the lump and the air is increased, the fuel spray is sufficiently diffused, the air-fuel mixture having a combustible mixing ratio reaches the vicinity of the spark plug, and the discharge amount of soot and the like can be reduced.
[0018]
Then, the fuel injection pulse width divided in the same cycle is set so that the injection pulse stop width provided therebetween becomes shorter, and the fuel spray is intermittently injected from the fuel injection valve. The region where the mixture ratio is formed can be limited to a narrow range near the spark plug, and the stratified combustion region where the air-fuel mixture is diluted is expanded to improve emission and reduce fuel consumption.
[0019]
The fuel injection control device for a direct injection type spark ignition engine according to claim 2 , wherein the fuel injection direction of the fuel injection valve is along the flow direction of the tumble. The air-fuel mixture swirls to form a substantially continuous air-fuel mixture in the vicinity of the spark plug, and the air-fuel mixture is stratified in the combustion chamber to ensure ignition and improve combustibility.
[0020]
4. The fuel injection control device for a direct injection type spark ignition engine according to claim 3 , wherein the fuel injection direction of the fuel injection valve is along the flow direction of the swirl, so that the fuel spray injected in stages together with the swirl The air-fuel mixture swirls to form a substantially continuous air-fuel mixture in the vicinity of the spark plug, and the air-fuel mixture is stratified in the combustion chamber to ensure ignition and improve combustibility.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0022]
As shown in FIG. 1, a combustion chamber 1 is defined between the cylinder head and the piston 5. The spark plug 7 faces the center of the combustion chamber 1, and two intake valves 8 and two exhaust valves 9 are provided opposite to each other with the spark plug 7 sandwiched between the combustion chamber ceiling wall inclined in a pent roof shape. .
[0023]
A fuel injection valve 6 facing the combustion chamber 1 from its side is provided on the combustion chamber ceiling wall. The fuel injection valve 6 is located on the side of each intake valve 8 and between each intake valve 8 and faces the combustion chamber 1.
[0024]
The fuel spray injected from the fuel injection valve 6 into the combustion chamber 1 at a predetermined timing is mixed with the air sucked into the cylinder from the intake port as each intake valve 8 is opened. The air-fuel mixture formed in the cylinder is ignited and burned through the spark plug 7 while being compressed by the piston 5. The burned gas lowers the piston 5 and extracts the rotational force via the crankshaft, and then is discharged from each exhaust port as the exhaust valve 8 is opened during the exhaust stroke in which the piston 5 moves up. Each of these processes is repeated continuously.
[0025]
In the present embodiment, the intake flow that equally divides into each intake port and flows into the cylinder swivels around an axis perpendicular to the cylinder center line on the crown of the piston 5 as indicated by an arrow in the figure. Create a tumble.
[0026]
The fuel injection direction of the fuel injection valve 6 is set in substantially the same direction as the tumble intake flow direction. As shown in FIGS. 3 and 4, the fuel spray injected from the fuel injection valve 6 expands in a conical shape centering on the center line I of the fuel injection valve 6.
[0027]
The fuel injection valve 6 has its valve opening timing (fuel injection timing) and valve opening period (fuel injection amount) controlled by a control unit (not shown) according to the operating state. The control unit outputs a pulse signal corresponding to the calculated fuel injection amount to a drive circuit (not shown) of the fuel injection valve 6. Along with this, a drive current corresponding to the pulse signal is sent from the drive circuit to the actuator of the fuel injection valve 6, and the needle of the fuel injection valve 6 is lifted to open the injection port. The longer the fuel injection pulse, the longer the valve opening period of the fuel injection valve 6, and the fuel injection amount increases.
[0028]
The control unit sets the fuel injection timing to an intake stroke in which the piston 5 descends in a predetermined homogeneous combustion region, and keeps the air-fuel ratio within a narrow range centered on the stoichiometric air-fuel ratio. On the other hand, the fuel injection timing is set to the latter half of the compression stroke in which the piston 5 rises in a predetermined stratified combustion region, and the air-fuel ratio is controlled to be leaner than the stoichiometric air-fuel ratio.
[0029]
In the stratified charge combustion region, the control unit divides the pulse signal output in the same cycle into a plurality of parts and performs fuel injection from the fuel injection valve 6 in multiple stages. Then, the fuel injection pulse width divided into a plurality of times in the same cycle is set so as to gradually become shorter as the latter stage of the injection. That is, as shown in FIG. 5, when the injection pulse width T is divided and output in three times, the first injection pulse width T 1 is set longer than the second injection pulse width T 2 , and the second injection is performed. The pulse width T 2 is set longer than the third injection pulse width T 3 .
[0030]
Furthermore, for each fuel injection pulse width divided in the same cycle, an injection pulse stop width provided therebetween is set to be short, and fuel spray from the fuel injection valve 6 is interrupted in the middle in the same cycle. Without intermittent injection. That is, as shown in FIG. 5, when the injection pulse width is divided into three times and output, the first pulse stop width I 1 is set shorter than the second injection pulse width T 2 and the second pulse stop. The width I 2 is set shorter than the third injection pulse width T 3 .
[0031]
FIG. 6 shows an air-fuel mixture concentration distribution in a cross section along the tumble flow direction (A-A line in FIG. 2). The air-fuel mixture produced by the fuel spray injected by the fuel injection pulse signal divided into three times is distributed.
[0032]
In FIG. 6, the fuel sprays injected by the three fuel injection pulse signals divided by the same stroke all form an air-fuel mixture that can be independently contained in the combustible air-fuel mixture concentration, and are injected by the first fuel injection pulse signal. The fuel spray is configured to create an air-fuel mixture that falls within the concentration of the combustible air-fuel mixture in the vicinity of the spark plug 7 that reaches the ignition timing.
[0033]
The flowchart of FIG. 8 shows a routine for controlling the fuel injection pulse signal, which is executed at regular intervals in the control unit.
[0034]
This will be described. First, in step 1, operating conditions such as engine speed and engine load are detected.
[0035]
Subsequently, the routine proceeds to step 2 where a fuel injection pulse width T is calculated according to detected values such as the engine speed and engine load.
[0036]
Subsequently, the routine proceeds to step 3 where the fuel injection pulse width T is divided into sub-times. As shown in FIG. 7, when the injection pulse width is divided into three times and output, the first injection pulse width T 1 , the second injection pulse width T 2, and the third injection pulse width T 3 are output. Is calculated so that the total value T 1 + T 2 + T 3 of each injection amount becomes the injection pulse width T.
[0037]
Subsequently, the routine proceeds to step 4 where the injection start crank angle for outputting each divided injection pulse signal is calculated from the injection start timing or the injection end timing corresponding to the detected values of the engine speed, the engine load and the like.
[0038]
Subsequently, the routine proceeds to step 5, and when the calculated injection start crank angle comes, a pulse signal is outputted from the control unit to the drive circuit to open the fuel injection valve 6, and this routine is ended.
[0039]
The operation will be described next.
[0040]
As shown in FIGS. 1 and 2, in the stratified combustion region where the load or rotation speed of the engine 30 is equal to or less than a predetermined value, fuel is injected in multiple stages from the fuel injection valve 6 in the latter half of the compression stroke in which the piston 5 ascends. . Since the tumble generated in the cylinder in the intake stroke continues until the latter half of the compression stroke, the fuel spray injected from the fuel injection valve 6 rotates together with the tumble.
[0041]
By injecting the fuel from the fuel injection valve 6 in multiple stages, it is possible to suppress the fuel concentration of the air-fuel mixture from becoming too high compared to the case where the fuel is continuously injected from the fuel injection valve 6, soot, etc. Emissions can be reduced.
[0042]
The injection pulse signal in the same cycle is divided into three times and output. In this case, the fuel spray 2 injected by the first injection pulse signal has a longer period of swirling with the tumble in the combustion chamber 1 than the fuel sprays 3 and 4 injected by the second and third injection pulse signals. However, since the injection amount is large, the air-fuel mixture mass diffuses moderately, and the air-fuel mixture having a combustible mixture ratio reaches the vicinity of the spark plug 7 that reaches the ignition timing.
[0043]
The fuel sprays 3 and 4 injected by the second and third injection pulse signals have a short period of diffusion along with the tumble, but the injection amount is smaller than the fuel spray injected by the first injection pulse signal. The contact area between the air-fuel mixture and air is increased, the fuel spray is sufficiently diffused, the air-fuel mixture with a combustible mixing ratio is distributed, and the discharge amount of soot and the like can be reduced.
[0044]
Since the fuel injection direction of the fuel injection valve 6 is along the tumble flow direction, the fuel sprays 2, 3 and 4 injected by the first, second and third injection pulse signals rotate together with the tumble. As shown in FIG. 6, the mixture concentration distribution is formed in the vicinity of the spark plug 7 so that the mixture is stratified in the combustion chamber 1, and ignition is performed reliably. Increases flammability.
[0045]
Also, the outer edge of the air-fuel mixture is more divided than the case where the injection pulse width T in the same cycle is divided and outputted, and the first injection pulse width is set longer than the second and third injection pulse widths. Diffusion and dilution beyond the combustible mixing ratio are suppressed, and the amount of unburned HC can be reduced.
[0046]
By setting the first pulse stop width I 1 shorter than the second injection pulse width T 2 and setting the second pulse stop width I 2 shorter than the third injection pulse width T 3 , the combustion chamber 1 It is possible to limit the region in which the mixture ratio is formed in a narrow range near the spark plug 7, expand the stratified combustion region in which the air-fuel mixture is diluted, improve emissions, and reduce fuel consumption. .
[0047]
Next, the embodiment shown in FIGS. 9 to 14 will be described. In addition, the same code | symbol is attached | subjected to a corresponding part with FIGS.
[0048]
In this embodiment, the intake passage is provided with a swirl control valve that increases the intake flow velocity of one intake port, and as shown by the arrow in FIG. It is supposed to be.
[0049]
The fuel injection direction of the fuel injection valve 6 is set substantially in the same direction as the swirl intake flow direction. That is, as shown in FIGS. 11 and 12, the fuel spray injected from the fuel injection valve 6 spreads conically around an axis inclined in the swirl turning direction with respect to the center line I of the fuel injection valve 6. .
[0050]
In the stratified combustion region, the control unit divides the pulse signal into sub-numbers and outputs it in the same cycle, and performs fuel injection from the fuel injection valve 6 in multiple stages.
[0051]
The fuel injection pulse width divided into a plurality of times in the same cycle is set so as to gradually become shorter as the latter stage of the injection. That is, as shown in FIG. 13, when the injection pulse width T is divided and output in three times, the first injection pulse width T 1 is set longer than the second injection pulse width T 2 , and the second injection is performed. The pulse width T 2 is set longer than the third injection pulse width T 3 .
[0052]
Furthermore, for each fuel injection pulse width divided in the same cycle, an injection pulse stop width provided therebetween is set to be short, and fuel spray from the fuel injection valve 6 is interrupted in the middle in the same cycle. There is no intermittent injection. That is, as shown in FIG. 13, when the injection pulse width is divided into three times and output, the first pulse stop width I 1 is set shorter than the second injection pulse width T 2 , and the second pulse stop. The width I 2 is set shorter than the third injection pulse width T 3 .
[0053]
FIG. 14 shows an air-fuel mixture concentration distribution in a cross section along the swirl flow direction (A-A line in FIG. 2). The air-fuel mixture produced by the fuel spray injected by the fuel injection pulse signal divided into three times is distributed.
[0054]
In FIG. 14, the fuel sprays injected by the three fuel injection pulse signals divided at the same stroke independently form an air-fuel mixture that falls within the combustible air-fuel mixture concentration, and are injected by the first fuel injection pulse signal. The fuel spray is configured to create an air-fuel mixture that falls within the concentration of the combustible air-fuel mixture in the vicinity of the spark plug 7 that reaches the ignition timing.
[0055]
The operation will be described next.
[0056]
In the stratified combustion region where the load or rotation speed of the engine 30 is equal to or less than a predetermined value, as shown in FIGS. 9 and 10, fuel is injected in multiple stages from the fuel injection valve 6 in the latter half of the compression stroke in which the piston 5 ascends. . Since the swirl generated in the cylinder in the intake stroke continues until the latter half of the compression stroke, the fuel spray injected from the fuel injection valve 6 swirls together with the swirl.
[0057]
By injecting the fuel from the fuel injection valve 6 in multiple stages, it is possible to suppress the fuel concentration of the air-fuel mixture from becoming too high compared to the case where the fuel is continuously injected from the fuel injection valve 6, soot, etc. Emissions can be reduced.
[0058]
The injection pulse signal in the same cycle is divided into three times and output. In this case, the fuel spray 2 injected by the first injection pulse signal has a longer period of swirling with the swirl in the combustion chamber 1 than the fuel sprays 3 and 4 injected by the second and third injection pulse signals. However, since the injection amount is large, the air-fuel mixture mass diffuses moderately, and the air-fuel mixture having a combustible mixture ratio reaches the vicinity of the spark plug 7 that reaches the ignition timing.
[0059]
The fuel sprays 3 and 4 injected by the second and third injection pulse signals have a short period of diffusion along with the swirl, but the injection amount is smaller than the fuel spray injected by the first injection pulse signal. The contact area between the air-fuel mixture and air is increased, the fuel spray is sufficiently diffused, the air-fuel mixture with a combustible mixing ratio is distributed, and the discharge amount of soot and the like can be reduced.
[0060]
Since the fuel injection direction of the fuel injection valve 6 is along the flow direction of the swirl, the fuel sprays 2, 3, and 4 injected by the first, second, and third injection pulse signals rotate together with the swirl. As shown in FIG. 6, the mixture concentration distribution is formed in the vicinity of the spark plug 7 so that the mixture is stratified in the combustion chamber 1, and ignition is performed reliably. Increases flammability.
[0061]
Also, the outer edge of the air-fuel mixture is more divided than the case where the injection pulse width T in the same cycle is divided and outputted, and the first injection pulse width is set longer than the second and third injection pulse widths. Diffusion and dilution beyond the combustible mixing ratio are suppressed, and the amount of unburned HC can be reduced.
[0062]
By setting the first pulse stop width I 1 shorter than the second injection pulse width T 2 and setting the second pulse stop width I 2 shorter than the third injection pulse width T 3 , the combustion chamber 1 It is possible to limit the region in which the mixture ratio is formed in a narrow range near the spark plug 7, expand the stratified combustion region in which the air-fuel mixture is diluted, improve emissions, and reduce fuel consumption. .
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a combustion chamber showing an embodiment of the present invention.
FIG. 2 is a plan view of the combustion chamber.
FIG. 3 is a front view showing the form of fuel spray.
FIG. 4 is a plan view showing the form of fuel spray.
FIG. 5 is a view similarly showing a fuel injection pulse signal.
FIG. 6 is a distribution diagram of the mixture concentration.
FIG. 7 is also a diagram showing a method for calculating a fuel injection pulse width.
FIG. 8 is a flowchart showing the control contents of the fuel injection valve.
FIG. 9 is a cross-sectional view of a combustion chamber showing another embodiment.
FIG. 10 is a plan view of the combustion chamber.
FIG. 11 is a front view showing the form of fuel spray.
FIG. 12 is a plan view showing the form of fuel spray.
FIG. 13 is a view similarly showing a fuel injection pulse signal.
FIG. 14 is a distribution diagram of the mixture concentration.
FIG. 15 is a sectional view of a combustion chamber showing a conventional example.
FIG. 16 is a sectional view of the combustion chamber.
FIG. 17 is a sectional view of the combustion chamber.
FIG. 18 is a view similarly showing a fuel injection pulse signal.
FIG. 19 is a plan view of the combustion chamber.
FIG. 20 is a distribution diagram of the mixture concentration.
[Explanation of symbols]
1 Combustion chamber 5 Piston 6 Fuel injection valve 7 Spark plug 8 Intake valve 9 Exhaust valve

Claims (3)

シリンダ内の混合気に点火する点火プラグと、
シリンダ内に燃料を噴射する燃料噴射弁と、
燃料噴射弁を開弁させる燃料噴射パルス信号を出力する筒内直噴式火花点火エンジンの燃料噴射制御装置において、
圧縮行程にて出力される燃料噴射パルス信号を複数に分割し、
分割された燃料噴射パルス信号のうち１回目の燃料噴射パルス幅を２回目以降の燃料噴射パルス幅より長く設定し、
前記分割された燃料噴射パルス幅の間の噴射パルス停止幅を、直後の燃料噴射パルス幅よりも短く設定し、
燃料噴射弁から燃料噴霧を間欠的に噴射し、
１回目の燃料噴射パルス信号によって噴射された燃料噴霧が点火プラグの近傍に可燃混合比の混合気をつくる構成とした
ことを特徴とする筒内直噴式火花点火エンジンの燃料噴射制御装置。A spark plug that ignites the air-fuel mixture in the cylinder;
A fuel injection valve for injecting fuel into the cylinder;
In a fuel injection control device for an in-cylinder direct injection spark ignition engine that outputs a fuel injection pulse signal for opening a fuel injection valve,
Divide the fuel injection pulse signal output in the compression stroke into multiple
Of the divided fuel injection pulse signals, the first fuel injection pulse width is set longer than the second and subsequent fuel injection pulse widths,
The injection pulse stop width between the divided fuel injection pulse widths is set shorter than the immediately following fuel injection pulse width,
The fuel spray is intermittently injected from the fuel injection valve,
A fuel injection control device for an in-cylinder direct injection spark ignition engine, characterized in that the fuel spray injected by the first fuel injection pulse signal creates a mixture having a combustible mixture ratio in the vicinity of the spark plug. 前記シリンダ内にタンブルを生起するタンブル生起手段を備え、
燃料噴射弁からタンブルの流れ方向に燃料を噴射する構成とした
ことを特徴とする請求項１に記載の筒内直噴式火花点火エンジンの燃料噴射制御装置。Tumble generating means for generating tumble in the cylinder,
The fuel injection control apparatus for a cylinder direct-injection spark-ignition engine according to claim 1, characterized in that the fuel injection valve configured to inject fuel into the tumble flow direction. 前記シリンダ内にスワールを生起するスワール生起手段を備え、
燃料噴射弁からスワールの流れ方向に燃料を噴射する構成とした
ことを特徴とする請求項１に記載の筒内直噴式火花点火エンジンの燃料噴射制御装置。Comprising swirl generating means for generating a swirl in the cylinder;
The fuel injection control apparatus for a cylinder direct-injection spark-ignition engine according to claim 1, characterized in that the arrangement for injecting the fuel from the fuel injection valve swirl flow direction.
JP24104997A 1997-09-05 1997-09-05 Fuel injection control device for in-cylinder direct injection spark ignition engine Expired - Lifetime JP3975517B2 (en)

Priority Applications (1)

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JP24104997A JP3975517B2 (en) 1997-09-05 1997-09-05 Fuel injection control device for in-cylinder direct injection spark ignition engine

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Application Number Priority Date Filing Date Title
JP24104997A JP3975517B2 (en) 1997-09-05 1997-09-05 Fuel injection control device for in-cylinder direct injection spark ignition engine

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EP1191199A1 (en) 1999-06-11 2002-03-27 Hitachi, Ltd. Cylinder injection engine and method of combusting the engine
JP3952693B2 (en) 2001-01-09 2007-08-01 日産自動車株式会社 In-cylinder direct fuel injection spark ignition engine fuel injection control device
DE10242226A1 (en) 2002-09-12 2004-03-25 Daimlerchrysler Ag Operating externally-ignited combustion engine involves injecting two sub-quantities during induction, third during compression, ignition between 0 and 100 degrees after end of third sub-quantity
FR2849898B1 (en) * 2003-01-13 2007-06-15 Renault Sa METHOD FOR CONTROLLING INTERNAL COMBUSTION ENGINE AND INTERNAL COMBUSTION ENGINE
DE10320848B4 (en) * 2003-05-09 2016-05-04 Daimler Ag Method for operating a spark-ignited internal combustion engine
DE10347474A1 (en) * 2003-10-01 2005-05-04 Bosch Gmbh Robert Method for outputting injection pulse widths in an internal combustion engine
JP4782836B2 (en) * 2005-09-17 2011-09-28 ダイムラー・アクチェンゲゼルシャフト Method of operating an externally ignited internal combustion engine
DE102006035139B4 (en) * 2005-11-08 2020-03-12 Daimler Ag Method for cold-running operation of a spark-ignition internal combustion engine
US7360522B2 (en) 2006-07-25 2008-04-22 General Electric Company System and method for operating a turbo-charged engine
JP6044603B2 (en) * 2014-07-23 2016-12-14 トヨタ自動車株式会社 Control device for internal combustion engine
JP2016130495A (en) * 2015-01-14 2016-07-21 トヨタ自動車株式会社 Internal combustion engine
WO2016140150A1 (en) * 2015-03-05 2016-09-09 日立オートモティブシステムズ株式会社 Fuel injection valve, control device for fuel injection valve, and control method
JP6597736B2 (en) * 2017-08-25 2019-10-30 マツダ株式会社 Engine control device

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