JP2004218522A

JP2004218522A - Control device for internal combustion engine equipped with variable compression ratio mechanism

Info

Publication number: JP2004218522A
Application number: JP2003006699A
Authority: JP
Inventors: Kazuhisa Mogi; 和久茂木
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 2003-01-15
Filing date: 2003-01-15
Publication date: 2004-08-05
Anticipated expiration: 2023-01-15
Also published as: JP4345307B2

Abstract

<P>PROBLEM TO BE SOLVED: To improve a fuel consumption rate in a medium load region in an internal combustion engine equipped with a variable compression ratio mechanism, a variable valve mechanism and a supercharging mechanism. <P>SOLUTION: A control unit 40, in the case of determining the operating load of the internal combustion engine 10 to be in a low load region, sets a high mechanical compression ratio and delays the closing timing of an intake valve without carrying out supercharging. The control unit 40, in the case of determining the operating load of the internal combustion engine 10 to be in the medium load region, sets the high mechanical compression ratio, delays the closing timing of the intake valve, and carries out supercharging. The control unit 40, in the case of determining the operating load of the internal combustion engine 10 to be in a high load region, sets a low mechanical compression ratio, advances the closing timing of the intake valve, and carries out supercharging. The control unit 40, upon completing the execution of conditions corresponding to load conditions, carries out the operation control of the internal combustion engine 10 under the executed conditions. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、圧縮比を変更可能な可変圧縮比機構、吸気バルブの開弁・閉弁時期を変更可能な可変動弁機構を備える内燃機関における内燃機関の制御装置に関する。
【０００２】
【従来の技術】
内燃機関の運転状態に応じて、内燃機関の圧縮比を変更する可変圧縮比機構が提案されている。また、内燃機関の運転状態に応じて、主に吸気バルブの開弁・閉弁時期を変更する可変動弁機構が実用化されている。さらに、内燃機関の気筒内に圧縮された吸入空気を供給する過給機構が実用化されている。
【０００３】
また、高効率、低燃費、高出力を得るために内燃機関の運転状態を低負荷領域、中負荷領域および高負荷領域の３つの領域に区分し、各負荷領域において、可変圧縮比機構、可変動弁機構、および過給機構の動作を制御する技術が提案されている（例えば、特許文献１）。この他にも、専らノッキングを抑制するために内燃機関の負荷に応じて可変圧縮比機構および過給機構を制御する技術が提案されている（例えば、特許文献２）。
【０００４】
【特許文献１】
特開昭６３−１２０８２０号公報
【特許文献２】
実開昭６３−１５００４８号公報
【０００５】
【発明が解決しようとする課題】
しかしながら、上記先行技術によっては、燃費率の向上が十分ではなく、特に中負荷領域における燃費率の向上が十分でないという問題があった。また、高負荷領域において出力トルクが頭打ちとなるという問題があった。
【０００６】
本発明は、上記課題を解決するためになされたものであり、可変圧縮比機構、可変動弁機構および過給機構を備える内燃機関において、中負荷領域における燃費率を向上させることを目的とする。また、可変圧縮比機構、可変動弁機構および過給機構を備える内燃機関において、高負荷領域における出力トルクの増大を図ることを目的とする。
【０００７】
【課題を解決するための手段および作用・効果】
上記課題を解決するために本発明の第１の態様は、内燃機関の気筒内と大気とを連通または遮断する吸気バルブを有する内燃機関の制御装置を提供する。本発明の第１の態様に係る内燃機関における制御装置は、前記吸気バルブの閉弁時期を変更する可変動弁機構と、前記内燃機関の機械的な圧縮比を変更する可変圧縮比機構と、前記内燃機関の気筒内へ圧縮された吸入空気を供給する過給機構と、前記内燃機関に対する要求トルクを検出する要求トルク検出手段と、前記検出された要求トルクが中負荷領域にある場合には、前記可変動弁機構によって前記吸気バルブの閉弁時期を遅らせ、前記可変圧縮比機構によって前記内燃機関の機械圧縮比を高くし、前記過給機構を作動させて前記内燃機関の気筒内へ圧縮された吸入空気を供給させる運転制御手段とを備えることを特徴とする。
【０００８】
本発明の第１の態様に係る内燃機関の制御装置によれば、要求トルクが中負荷領域にある場合には、可変動弁機構によって吸気バルブの閉弁時期を遅らせ、可変圧縮比機構によって内燃機関の機械圧縮比を高くし、過給機構を作動させて内燃機関の気筒内へ圧縮された吸入空気を供給させるので、可変圧縮比機構、可変動弁機構および過給機構を備える内燃機関において、中負荷領域における燃費率を向上させることができる。
【０００９】
本発明の第１の態様に係る内燃機関の制御装置はさらに、前記過給機構より前記内燃機関の気筒内に導入される圧縮された吸入空気の温度を低下させる冷却器を備えても良い。かかる場合には、気筒内にて圧縮された後も吸入空気の温度を低く保つことができるので、過給器を作動させた場合のノッキングの発生をより防止することができる。
【００１０】
本発明の第１の態様に係る内燃機関の制御装置において、前記中負荷領域は、前記過給機構作動時において前記内燃機関が出力する最大トルクの約１／２のトルクが要求トルクとして要求される負荷領域であっても良い。
【００１１】
本発明の第１の態様に係る内燃機関の制御装置において、前記運転制御手段は、前記検出された要求トルクが前記中負荷領域よりも負荷が大きい高負荷領域にある場合には、前記可変動弁機構によって前記吸気バルブの閉弁時期を進め、前記可変圧縮比機構によって前記内燃機関の機械圧縮比を低くし、前記過給機構を作動させて前記内燃機関の気筒内へ圧縮された吸入空気を供給させても良い。
【００１２】
本発明の第１の態様に係る内燃機関における制御装置によれば、要求トルクが中負荷領域よりも負荷が大きい高負荷領域にある場合には、可変動弁機構によって吸気バルブの閉弁時期を進め、可変圧縮比機構によって内燃機関の機械圧縮比を低くし、過給機構を作動させて内燃機関の気筒内へ圧縮された吸入空気を供給させるので、可変圧縮比機構、可変動弁機構および過給機構を備える内燃機関において、高負荷領域における出力トルクの増大を図ることができる。
【００１３】
本発明の第２の態様は、内燃機関の制御装置を提供する。本発明の第２の態様に係る内燃機関における制御装置は、過給機構と、少なくとも吸気バルブの閉弁時期を変更させる可変動弁機構と、前記内燃機関の機械的な圧縮比を変更させる可変圧縮比機構と、前記内燃機関に対する要求トルクを検出する要求トルク検出手段と、前記検出された要求トルクが第１の負荷領域にある場合には、前記可変動弁機構によって前記吸気バルブの閉弁時期を遅角させ、前記可変圧縮比機構によって前記内燃機関の機械的な圧縮比を高くし、前記過給機構による過給を行わず、前記検出された要求トルクが前記第１の負荷領域よりも大きい第２の負荷領域にある場合には、前記可変動弁機構によって前記吸気バルブの閉弁時期を遅角させ、前記可変圧縮比機構によって前記内燃機関の機械圧縮比を高くし、前記過給機構による過給を行い、前記検出された要求トルクが前記第２の負荷領域よりも大きい第３の負荷領域にある場合には、前記可変動弁機構によって前記吸気バルブの閉弁時期を進角させ、前記可変圧縮比機構によって前記内燃機関に機械圧縮比を低くし、前記過給機構による過給を行う運転制御手段とを備えることを特徴とする。
【００１４】
本発明の第２の態様に係る内燃機関における制御装置によれば、要求トルクが中負荷領域にある場合には、可変動弁機構によって吸気バルブの閉弁時期を遅らせ、可変圧縮比機構によって内燃機関の機械圧縮比を高くし、過給機構を作動させて内燃機関の気筒内へ圧縮された吸入空気を供給させると共に、要求トルクが中負荷領域よりも負荷が大きい高負荷領域にある場合には、可変動弁機構によって吸気バルブの閉弁時期を進め、可変圧縮比機構によって内燃機関の機械圧縮比を低くし、過給機構を作動させて内燃機関の気筒内へ圧縮された吸入空気を供給させる。したがって、可変圧縮比機構、可変動弁機構および過給機構を備える内燃機関において、中負荷領域における燃費率を向上させることができると共に、高負荷領域における出力トルクの増大を図ることができる。
【００１５】
本発明の第２の態様に係る内燃機関における制御装置において、前記運転制御手段は、前記第２の負荷領域から前記第３の負荷領域へと移行するときには、前記内燃機関の実圧縮比を一定に保つよう前記可変動弁機構および前記可変圧縮比機構を制御しても良い。また、前記運転制御手段は、前記可変動弁機構によって前記吸気バルブの閉弁時期を進角させ、前記可変圧縮比機構によって前記内燃機関の機械圧縮比を低くすることによって、前記内燃機関の実圧縮比を一定に保っても良い。かかる場合には、第２の負荷領域を実質的に拡張することとなり、燃費性能を向上させることができる。
【００１６】
本発明の第３の態様は、内燃機関の気筒内と大気とを連通または遮断する吸気バルブを有する内燃機関の制御装置を提供する。本発明の第３の態様に係る内燃機関における制御装置は、前記吸気バルブの閉弁時期を変更する可変動弁機構と、前記内燃機関の機械的な圧縮比を変更する可変圧縮比機構と、前記内燃機関の気筒内へ圧縮された吸入空気を供給する過給機構と、前記過給機構より前記内燃機関の気筒内に導入される圧縮された吸入空気の温度を低下させる冷却器と、前記内燃機関に対する要求トルクを検出する要求トルク検出手段と、前記検出された要求トルクが、前記過給機構作動時において前記内燃機関が出力する最大トルクの約１／２のトルクよりも大きなトルクが要求される高負荷領域にある場合には、前記可変動弁機構によって前記吸気バルブの閉弁時期を進め、前記可変圧縮比機構によって前記内燃機関の機械圧縮比を低くし、前記過給機構を作動させて前記内燃機関の気筒内へ圧縮された吸入空気を供給させる運転制御手段とを備えることを特徴とする。
【００１７】
本発明の第３の態様に係る内燃機関における制御装置によれば、検出された要求トルクが、過給機構作動時において内燃機関が出力する最大トルクの約１／２のトルクよりも大きなトルクが要求される高負荷領域にある場合には、可変動弁機構によって吸気バルブの閉弁時期を進め、可変圧縮比機構によって内燃機関の機械圧縮比を低くし、過給機構を作動させて内燃機関の気筒内へ圧縮された吸入空気を供給させるので、可変圧縮比機構、可変動弁機構および過給機構を備える内燃機関において、高負荷領域における出力トルクの増大を図ることができる。
【００１８】
【発明の実施の形態】
以下、図面を参照しつつ実施例に基づいて、本発明に係る内燃機関の制御装置について説明する。
【００１９】
図１を参照して本実施例に係る内燃機関の制御装置の概略構成について説明する。図１は本実施例に係る内燃機関の制御装置の概略構成を示す説明図である。
【００２０】
本実施例に係る内燃機関の制御装置は、気筒内噴射型内燃機関、内燃機関の運転状態を制御する制御ユニットおよび内燃機関の運転状態を検出する各種センサを備えている。内燃機関１０は、内部に複数のシリンダ１１を有するシリンダブロック１２、シリンダ１１内を往復動するピストン１３、シリンダブロック１２の底部に配置されたクランクケース１４、シリンダブロック１２（シリンダ１１）の上部に配置されたシリンダヘッド１５を備えている。
【００２１】
本実施例における内燃機関１０には、内燃機関１０の機械圧縮比を所定の範囲内において任意に設定可能な可変圧縮比機構２０が備えられている。可変圧縮比機構２０は、シリンダブロック１２をクランクケース１４に対してピストン１２の運動方向（シリンダ１１の軸方向）に移動させることによって圧縮比を変更する。具体的には、シリンダブロック１２側に備えられたアクチュエータ２１（例えば、モータ）によってシリンダブロック１２の長手方向両側に配置された偏心カム（図示しない）を駆動して、シリンダブロック１２をクランクケース１４から離間若しくは密着させる。シリンダブロック１２がクランクケース１４から離間する方向へ移動させることによって機械圧縮比は低くなる。
【００２２】
シリンダヘッド１５は、各シリンダ１１毎に吸気ポート１６および排気ポート１７を有している。各吸気ポート１６には、吸気側カムＩＣによって駆動されて吸気ポート１６を開閉する吸気バルブ１６１が配置されており、各排気ポート１７には、排気側カムＥＣによって駆動されて排気ポート１７を開閉する排気バルブ１７１が配置されている。シリンダヘッド１５には、この他に、各シリンダ１１に対応する位置に火花点火のための点火プラグ３１が配置されている。
【００２３】
吸気側カムＩＣ（吸気側カムシャフト）には、クランクシャフトに対する吸気側カムシャフトの位相を変位させて、吸気バルブ１６１の開弁時期および閉弁時期を通常タイミング（進角）に対して遅らせる（遅角させる）可変動弁機構２５が備えられている。可変動弁機構２５は、例えば、モータ、油圧制御バルブといったアクチュエータ２６によってカムシャフトを変位させる。なお、可変動弁機構２５には、バルブタイミングを変更するもののみならず、作用角、バルブリフト量を変更するものも含まれる。本実施例では、吸気バルブ１６１の閉弁時期を遅らせることができればどのような可変動弁機構であっても良い。また、吸気バルブ１６１をアクチュエータによって直接駆動するものであっても良い。
【００２４】
各吸気ポート１６には、吸気管１８の分岐端が連結され、各排気ポート１７には、排気管（排気マニホールド）１９の分岐端が連結されている。吸気管１９の途中には、燃焼室への流入吸気量を制御する吸気制御バルブ３０が配置されている。
【００２５】
吸気管１８および排気管１９の途中には、排気管１９を流れる排気ガス流によって吸入空気を圧縮する過給器２８が備えられている。過給器２８には、過給圧力を任意の値に設定可能なウェストゲートバルブ２８１が備えられている。ウェストゲートバルブ２８１が開かれると、排気ガスは過給器２８の排気側タービンを迂回して大気中に放出されるため過給器２８は作動しない。吸気管１８には、過給器２８よりも下流側に、過給された吸入空気を冷却するためのインタークーラー（冷却器）が配置されている。なお、過給器２８は、排気ガス流によって吸入空気を圧縮するものばかりでなく、クランクシャフトからの動力によって機械的に駆動されて吸入空気を圧縮するものも含まれる。
【００２６】
各吸気ポート１６には燃料噴射弁ＩＪが配置されている。すなわち、本実施例に用いられる内燃機関１０はポート噴射タイプの内燃機関である。各燃料噴射弁ＩＪは、燃料デリバリパイプＦＤを介して燃料が供給される。
【００２７】
制御ユニット４０は、演算処理機能、マップ、プログラム等を格納する記憶機能を備えている。制御ユニット４０には、アクセルペダルの踏み込み量を検出するアクセルポジションセンサ５０、車両速度を検出する車速センサ５１、機関回転数を検出するクランクポジションセンサ５２といった各種センサが接続されており、内燃機関１０の運転状態を検出する各種センサからの信号が入力される。制御ユニット４０には、燃料噴射弁ＩＪ、可変圧縮比機構２０のアクチュエータ２１、可変動弁機構２５のアクチュエータ２６、ウェストゲートバルブ２８１、吸気制御バルブ３０、点火プラグ３１が接続されており、吸気バルブ１６１の開弁・閉弁時期、機械圧縮比、過給のオン・オフ、燃料噴射時期、点火時期、吸入空気量等が適宜制御される。
【００２８】
本実施例に係る内燃機関の制御装置によって実行される内燃機関の運転制御処理について図２〜図８を参照して説明する。図２は本実施例における内燃機関の運転制御処理において実行される処理ルーチンを示すフローチャートである。図３は要求トルクおよび機関回転数に基づいて内燃機関１０の負荷領域を判定するためのマップの一例を示す説明図である。図４は判定された負荷領域に応じて設定される負荷別制御条件を示す説明図である。図５は吸気バルブの閉弁時期の変化を示す説明図である。図６は従来の制御に対する本実施例の利点を説明する、低・中・高負荷領域における燃費率とトルクとの関係を表す特性線を示す説明図である。図７は特に中負荷領域における本実施例と従来制御との燃費率とトルクとの対比を示す説明図である。図８は本実施例における、中負荷領域から高負荷領域への移行時における吸気バルブタイミングによる圧縮比の変化、機械圧縮比の変化、実圧縮比の変化の様子を模式的に示す説明図である。
【００２９】
図２を参照して内燃機関の運転制御処理について説明する。本処理ルーチンは所定の時間間隔にて繰り返し実行される。制御ユニット４０は、アクセルポジションセンサ５０によって検出されたアクセルペダルの踏み込み量に基づいて要求トルクを検出し（ステップＳ１００）、算出された要求トルクとクランクポジションセンサから検出された機関回転数とをパラメータとして図３に示すマップから負荷領域を判定する（ステップＳ１１０）。
【００３０】
制御ユニット４０は、内燃機関１０の運転負荷が低負荷領域にあると判定した場合には、圧縮比、吸気バルブ閉弁時期および過給状態を図４に示す低負荷領域条件に設定する（ステップＳ１２０）。すなわち、機械圧縮比は高く設定され、吸気バルブの閉弁時期は図５に示すように遅角され、過給は行わない。制御ユニット４０は、アクチュエータ２１に対して駆動信号を送信してシリンダブロック１２とクランクケース１４とを密着させることによって機械圧縮比を高くし、アクチュエータ２６に対して駆動信号を送信して吸気バルブの閉弁時期を通常タイミングより遅角させ、ウェストゲートバルブ２８１に対して駆動信号を送信してウェストゲートバルブ２８１を開く（ステップＳ１３０）。
【００３１】
この結果、吸気バルブ１６１の遅閉じによってポンピングロスが低減され、また、機械圧縮比が高く設定されるので、図６に示すように燃費率を下げる（低燃費化）を実現することができる。
【００３２】
制御ユニット４０は、内燃機関１０の運転負荷が中負荷領域にあると判定した場合には、圧縮比、吸気バルブ閉弁時期および過給状態を図４に示す中負荷領域条件に設定する（ステップＳ１４０）。すなわち、機械圧縮比は高く設定され、吸気バルブの閉弁時期は図５に示すように遅角され、過給を実行する。制御ユニット４０は、アクチュエータ２１に対して駆動信号を送信してシリンダブロック１２とクランクケース１４とを密着させることによって機械圧縮比を高くし、アクチュエータ２６に対して駆動信号を送信して吸気バルブの閉弁時期を通常タイミングより遅角させ、ウェストゲートバルブ２８１に対して駆動信号を送信してウェストゲートバルブ２８１を閉じる（ステップＳ１５０）。
【００３３】
本実施例に係る内燃機関の制御装置では、中負荷領域において機械圧縮比を高く設定し、吸気バルブ１６１を遅閉じし、過給を実行するので（本実施例：図６中Ｌ１）、機械圧縮比を低く設定し、吸気バルブ１６１を早閉じし（通常のタイミング）、過給を実行しない場合（従来制御：図６中Ｌ２）と比較して、燃費率を下げる（低燃費化）を図ることができる。なお、中負荷領域とは、例えば、過給器２８の作動時において内燃機関１０が出力可能な最大トルクの約１／２のトルク程度の負荷領域を言う。
【００３４】
すなわち、本実施例によれば、機械圧縮比を高く設定することによって膨張の度合いが高められるため、混合気の燃焼により得られた圧力がピストンに効率的に伝達され（燃焼圧力の損失の低減）、機械圧縮比が低い場合よりも燃費を向上させることができる。また、吸気バルブ１６１の遅閉じによって、吸気バルブ１６１を通常のタイミング（進角）で閉じる場合と比較して吸入空気量が減少するため図７中特性線Ｌ１上に中黒点で示すように遅角時トルクしか出力できないが、減少した吸入空気量を過給によって補うことにより吸気バルブ１６１の閉弁時期を進角させた場合（図７中Ｌ２）の進角トルク（図７中Ｌ２上の中黒点）と同様のトルクを得ることができる。
【００３５】
一般的に、機械圧縮比が高い場合には、過給を行うことによるノッキングの発生が問題となるが、本実施例では、吸気バルブ１６１の閉弁時期を遅らせることによって吸気バルブ１６１の閉弁時期によって定まる圧縮比（吸気バルブ１６１が閉弁してからピストン１３が圧縮上死点に到達するまでの圧縮比）を下げ、実圧縮比を低くして圧縮による混合気（吸気）の温度上昇を小さくすると共に、過給器２８によって圧縮された吸気をインタークーラー２９によって冷却する。この結果、点火前の混合気温度の上昇が抑制されノッキングを抑制することができる。なお、実圧縮比とは、吸気バルブ１６１の閉弁時期と機械圧縮比で定まるシリンダ１１内における現実の圧縮比を意味する。
【００３６】
したがって、従来制御によって得られるトルクと同一のトルクをより低い燃費にて得ることができる。
【００３７】
制御ユニット４０は、内燃機関１０の運転負荷が高負荷領域にあると判定した場合には、圧縮比、吸気バルブ閉弁時期および過給状態を図４に示す高負荷領域条件に設定する（ステップＳ１６０）。すなわち、機械圧縮比は低く設定され、吸気バルブの閉弁時期を図５に示すように進角させ、過給を実行する。制御ユニット４０は、アクチュエータ２１に対して駆動信号を送信してシリンダブロック１２とクランクケース１４とを離間させることによって機械圧縮比を低くし、アクチュエータ２６に対して駆動信号を送信して吸気バルブの閉弁時期を通常タイミングである進角時期に変更させ、ウェストゲートバルブ２８１に対して駆動信号を送信してウェストゲートバルブ２８１を閉じる（ステップＳ１７０）。
【００３８】
中負荷領域から高負荷領域への切り替えに際しては、制御ユニット４０は、吸気バルブ１６１の閉弁時期の切り替え（遅角から進角）と共に内燃機関１０の機械圧縮比の切り替え（高圧縮比から低圧縮比）を同時に実行して、図８に示すように中負荷領域から高負荷領域への移行時における実圧縮比を一定に保つ。
【００３９】
本実施例に係る内燃機関の制御装置では、高負荷領域において機械圧縮比を低く設定し、吸気バルブ１６１を早閉じし、過給を実行するので（本実施例：図６中Ｌ１）、機械圧縮比を低く設定し、吸気バルブ１６１を遅閉じし（通常のタイミング）、過給を実行する場合（従来制御：図６中Ｌ２）と比較して、燃費率を下げる（低燃費化）と共により大きなトルクを得ることができる。
【００４０】
すなわち、従来制御では吸気バルブ１６１の閉弁時期が遅角されていたため図７中Ｌ３上に中黒点で示す遅角時トルクから過給器によって更なる出力トルクを得ていた（図７中Ｌ３）ので、到達可能な出力トルクが小さかった。これに対して、本実施例では、図７中特性線Ｌ４として示すように、吸気バルブ１６１の閉弁時期を進角（通常のタイミング）させているので過給器によらなくとも進角時トルク（特性線Ｌ４上の中黒点）を得ることが可能となり、過給器を使用することによって更に大きなトルクを得ることができる。
【００４１】
制御ユニット４０は、負荷条件に応じた条件の実行が終了すると、実行された条件下において内燃機関１０の運転制御を実行し（ステップＳ１８０）、本処理ルーチンを終了する。具体的には、内燃機関１０の運転状態（負荷）に応じて吸気バルブ３０の開弁角度の制御、燃料噴射時期制御並びに点火時期制御を実行する。
【００４２】
以上説明したように、本実施例に係る内燃機関の制御装置によれば、中負荷領域において機械圧縮比を高く設定し、吸気バルブ１６１を遅閉じし、過給を実行するので、従来制御と比較して中負荷領域における燃費率を向上することができる。また、高負荷領域においては、機械圧縮比を低く設定し、吸気バルブ１６１を早閉じし、過給を実行するので、従来制御と同等の燃費率において出力トルクを増大させることができる。
【００４３】
また、本実施例に係る内燃機関の制御装置によれば、中負荷領域から高負荷領域への移行時における実圧縮比を一定に保つので、略中負荷領域を拡大することが可能となり、圧縮比に起因する燃費の向上を図ることができる。
【００４４】
・その他の実施例：
上記実施例では、可変圧縮比機構２０としてシリンダブロック１２がクランクケース１４に対して移動するシリンダ伸縮タイプを例に取って説明したが、この他にも、例えば、ピストンコンロッドの中間にジョイント部を設け、ピストンの上死点位置を変更する中間折れコンロッドタイプを用いても良い。すなわち、内燃機関１０の機械圧縮比（幾何学圧縮比）を変更可能な機構を備える可変圧縮機構であれば上記実施例によって、可変動弁機構２５、過給器２８と相まって中負荷領域における燃費性能の向上、高負荷領域における出力トルクの増大といった効果を得ることができる。
【００４５】
以上、いくつかの実施例に基づき本発明に係る内燃機関の制御装置について説明してきたが、上記した発明の実施の形態は、本発明の理解を容易にするためのものであり、本発明を限定するものではない。本発明は、その趣旨並びに特許請求の範囲を逸脱することなく、変更、改良され得ると共に、本発明にはその等価物が含まれることはもちろんである。
【図面の簡単な説明】
【図１】本実施例に係る内燃機関の制御装置の概略構成を示す説明図である。
【図２】本実施例における内燃機関の運転制御処理において実行される処理ルーチンを示すフローチャートである。
【図３】要求トルクおよび機関回転数に基づいて内燃機関１０の負荷領域を判定するためのマップの一例を示す説明図である。
【図４】判定された負荷領域に応じて設定される負荷別制御条件を示す説明図である。
【図５】吸気バルブの閉弁時期の変化を示す説明図である。
【図６】従来の制御に対する本実施例の利点を説明する、低・中・高負荷領域における燃費率とトルクとの関係を表す特性線を示す説明図である。
【図７】特に中負荷領域における本実施例と従来制御との燃費率とトルクとの対比を示す説明図である。
【図８】本実施例における、中負荷領域から高負荷領域への移行時における吸気バルブタイミングによる圧縮比の変化、機械圧縮比の変化、実圧縮比の変化の様子を模式的に示す説明図である。
【符号の説明】
１０…内燃機関
１１…シリンダ
１２…シリンダブロック
１３…ピストン
１４…クランクケース
１５…シリンダヘッド
１６…吸気ポート
１６１…吸気バルブ
１７…排気ポート
１７１…排気バルブ
１８…吸気管
１９…排気管
２０…可変圧縮比機構
２１…アクチュエータ
２５…可変動弁機構
２６…アクチュエータ
２８…過給器
２８１…ウェストゲートバルブ
２９…インタークーラー
３０…吸気制御バルブ
３１…昇圧ポンプ
３２…点火プラグ
４０…制御ユニット
５０…アクセル開度センサ
５１…速度センサ
５２…クランクポジションセンサ
ＩＣ…吸気側カム
ＥＣ…排気側カム
ＩＪ…燃料噴射弁（インジェクタ）
ＦＤ…燃料デリバリパイプ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control apparatus for an internal combustion engine including an adjustable compression ratio mechanism capable of changing a compression ratio and a variable valve mechanism capable of changing a valve opening / closing timing of an intake valve.
[0002]
[Prior art]
A variable compression ratio mechanism that changes the compression ratio of an internal combustion engine according to the operating state of the internal combustion engine has been proposed. Also, a variable valve operating mechanism that mainly changes the valve opening / closing timing of an intake valve according to the operating state of an internal combustion engine has been put to practical use. Further, a supercharging mechanism for supplying compressed intake air into a cylinder of an internal combustion engine has been put to practical use.
[0003]
In order to obtain high efficiency, low fuel consumption, and high output, the operating state of the internal combustion engine is divided into three areas, a low load area, a medium load area, and a high load area. A technique for controlling the operation of a variable valve mechanism and a supercharging mechanism has been proposed (for example, Patent Document 1). In addition, a technique for controlling a variable compression ratio mechanism and a supercharging mechanism in accordance with the load of an internal combustion engine in order to exclusively suppress knocking has been proposed (for example, Patent Document 2).
[0004]
[Patent Document 1]
JP-A-63-120820 [Patent Document 2]
JP-A-63-150048 [0005]
[Problems to be solved by the invention]
However, the prior art described above has a problem that the fuel efficiency is not sufficiently improved, particularly in a medium load region. Further, there is a problem that the output torque reaches a peak in a high load region.
[0006]
SUMMARY An advantage of some aspects of the invention is to improve the fuel efficiency in a medium load region in an internal combustion engine including a variable compression ratio mechanism, a variable valve mechanism, and a supercharging mechanism. . Another object of the present invention is to increase output torque in a high load region in an internal combustion engine including a variable compression ratio mechanism, a variable valve mechanism, and a supercharging mechanism.
[0007]
[Means for Solving the Problems and Functions / Effects]
In order to solve the above-mentioned problems, a first aspect of the present invention provides a control device for an internal combustion engine having an intake valve for communicating or shutting off the inside of a cylinder of the internal combustion engine and the atmosphere. A control device for an internal combustion engine according to a first aspect of the present invention includes a variable valve mechanism that changes a valve closing timing of the intake valve, a variable compression ratio mechanism that changes a mechanical compression ratio of the internal combustion engine, A supercharging mechanism that supplies compressed intake air into a cylinder of the internal combustion engine, a required torque detecting unit that detects a required torque for the internal combustion engine, and a case where the detected required torque is in a medium load region. The variable valve mechanism delays the closing timing of the intake valve, the variable compression ratio mechanism increases the mechanical compression ratio of the internal combustion engine, and operates the supercharging mechanism to compress the cylinder into the cylinder of the internal combustion engine. Operation control means for supplying the selected intake air.
[0008]
According to the control device for an internal combustion engine according to the first aspect of the present invention, when the required torque is in the medium load region, the closing timing of the intake valve is delayed by the variable valve operating mechanism, and the internal combustion engine is controlled by the variable compression ratio mechanism. Since the mechanical compression ratio of the engine is increased and the supercharge mechanism is operated to supply the compressed intake air into the cylinder of the internal combustion engine, the internal combustion engine having the variable compression ratio mechanism, the variable valve mechanism, and the supercharge mechanism Thus, the fuel efficiency in the medium load region can be improved.
[0009]
The control device for an internal combustion engine according to the first aspect of the present invention may further include a cooler that lowers the temperature of compressed intake air introduced into the cylinder of the internal combustion engine from the supercharging mechanism. In such a case, since the temperature of the intake air can be kept low even after being compressed in the cylinder, knocking when the supercharger is operated can be further prevented.
[0010]
In the control device for an internal combustion engine according to the first aspect of the present invention, in the medium load region, a torque that is about ２ of a maximum torque output by the internal combustion engine when the supercharging mechanism is operating is required as a required torque. Load region.
[0011]
In the control device for an internal combustion engine according to the first aspect of the present invention, when the detected required torque is in a high load region where a load is larger than that in the medium load region, the operation control means may perform the variable operation. The closing timing of the intake valve is advanced by a valve mechanism, the mechanical compression ratio of the internal combustion engine is reduced by the variable compression ratio mechanism, and the intake air compressed into the cylinder of the internal combustion engine by operating the supercharging mechanism May be supplied.
[0012]
According to the control device for the internal combustion engine according to the first aspect of the present invention, when the required torque is in the high load region where the load is larger than the medium load region, the closing timing of the intake valve is set by the variable valve mechanism. Advance, the mechanical compression ratio of the internal combustion engine is lowered by the variable compression ratio mechanism, and the supercharging mechanism is operated to supply the compressed intake air into the cylinder of the internal combustion engine, so that the variable compression ratio mechanism, the variable valve operating mechanism and In the internal combustion engine including the supercharging mechanism, the output torque in a high load region can be increased.
[0013]
A second aspect of the present invention provides a control device for an internal combustion engine. A control device for an internal combustion engine according to a second aspect of the present invention includes a supercharging mechanism, a variable valve mechanism that changes at least a closing timing of an intake valve, and a variable valve mechanism that changes a mechanical compression ratio of the internal combustion engine. A compression ratio mechanism, required torque detecting means for detecting required torque for the internal combustion engine, and closing the intake valve by the variable valve mechanism when the detected required torque is in the first load region. The timing is retarded, the mechanical compression ratio of the internal combustion engine is increased by the variable compression ratio mechanism, the supercharging mechanism is not supercharged, and the detected required torque is higher than the first load region. When the engine is in the second load region, the valve closing timing of the intake valve is retarded by the variable valve mechanism, and the mechanical compression ratio of the internal combustion engine is increased by the variable compression ratio mechanism. When supercharging is performed by a mechanism, and the detected required torque is in a third load area that is larger than the second load area, the variable valve mechanism advances the valve closing timing of the intake valve. An operation control means for lowering the mechanical compression ratio of the internal combustion engine by the variable compression ratio mechanism and performing supercharging by the supercharging mechanism is provided.
[0014]
According to the control device for the internal combustion engine according to the second aspect of the present invention, when the required torque is in the medium load region, the closing timing of the intake valve is delayed by the variable valve operating mechanism, and the internal combustion engine is controlled by the variable compression ratio mechanism. When the mechanical compression ratio of the engine is increased, the supercharging mechanism is operated to supply the compressed intake air into the cylinder of the internal combustion engine, and when the required torque is in a high load region where the load is larger than the medium load region. Uses a variable valve mechanism to advance the closing timing of the intake valve, a variable compression ratio mechanism to lower the mechanical compression ratio of the internal combustion engine, and activates the supercharging mechanism to reduce the intake air compressed into the cylinder of the internal combustion engine. Let it be supplied. Therefore, in the internal combustion engine including the variable compression ratio mechanism, the variable valve mechanism, and the supercharging mechanism, the fuel efficiency in the medium load region can be improved, and the output torque in the high load region can be increased.
[0015]
In the control device for an internal combustion engine according to a second aspect of the present invention, the operation control means keeps the actual compression ratio of the internal combustion engine constant when shifting from the second load range to the third load range. The variable valve mechanism and the variable compression ratio mechanism may be controlled so as to maintain Further, the operation control means advances the valve closing timing of the intake valve by the variable valve operating mechanism and lowers the mechanical compression ratio of the internal combustion engine by the variable compression ratio mechanism, thereby realizing the internal combustion engine. The compression ratio may be kept constant. In such a case, the second load region is substantially expanded, and the fuel efficiency can be improved.
[0016]
A third aspect of the present invention provides a control device for an internal combustion engine having an intake valve for communicating or shutting off the inside of a cylinder of the internal combustion engine and the atmosphere. A control device for an internal combustion engine according to a third aspect of the present invention includes a variable valve mechanism for changing a valve closing timing of the intake valve, a variable compression ratio mechanism for changing a mechanical compression ratio of the internal combustion engine, A supercharging mechanism for supplying compressed intake air into a cylinder of the internal combustion engine, a cooler for reducing a temperature of compressed intake air introduced into the cylinder of the internal combustion engine from the supercharging mechanism, Request torque detecting means for detecting a required torque for the internal combustion engine, wherein the detected required torque requires a torque larger than about one-half the maximum torque output by the internal combustion engine when the supercharging mechanism is operating. In the high load region, the closing timing of the intake valve is advanced by the variable valve operating mechanism, the mechanical compression ratio of the internal combustion engine is reduced by the variable compression ratio mechanism, and the supercharging mechanism is operated. By moving, characterized in that it comprises a driving control means for supplying the intake air compressed into the cylinder of the internal combustion engine.
[0017]
According to the control device for the internal combustion engine according to the third aspect of the present invention, the detected required torque is a torque larger than about の of the maximum torque output by the internal combustion engine during the operation of the supercharging mechanism. When the engine is in the required high load range, the closing timing of the intake valve is advanced by the variable valve operating mechanism, the mechanical compression ratio of the internal combustion engine is reduced by the variable compression ratio mechanism, and the supercharging mechanism is operated to operate the internal combustion engine. The compressed intake air is supplied into the cylinder, and therefore, in the internal combustion engine including the variable compression ratio mechanism, the variable valve mechanism, and the supercharging mechanism, the output torque in a high load region can be increased.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a control device for an internal combustion engine according to the present invention will be described based on an embodiment with reference to the drawings.
[0019]
With reference to FIG. 1, a schematic configuration of a control device for an internal combustion engine according to the present embodiment will be described. FIG. 1 is an explanatory diagram showing a schematic configuration of a control device for an internal combustion engine according to the present embodiment.
[0020]
The control apparatus for an internal combustion engine according to the present embodiment includes an in-cylinder injection type internal combustion engine, a control unit for controlling the operation state of the internal combustion engine, and various sensors for detecting the operation state of the internal combustion engine. The internal combustion engine 10 includes a cylinder block 12 having a plurality of cylinders 11 therein, a piston 13 reciprocating in the cylinder 11, a crankcase 14 disposed at the bottom of the cylinder block 12, and an upper part of the cylinder block 12 (cylinder 11). The cylinder head 15 is provided.
[0021]
The internal combustion engine 10 according to the present embodiment includes a variable compression ratio mechanism 20 that can arbitrarily set a mechanical compression ratio of the internal combustion engine 10 within a predetermined range. The variable compression ratio mechanism 20 changes the compression ratio by moving the cylinder block 12 with respect to the crankcase 14 in the movement direction of the piston 12 (the axial direction of the cylinder 11). Specifically, eccentric cams (not shown) arranged on both longitudinal sides of the cylinder block 12 are driven by an actuator 21 (for example, a motor) provided on the cylinder block 12 side, and the cylinder block 12 is moved to the crankcase 14. Away from or close to. The mechanical compression ratio is lowered by moving the cylinder block 12 away from the crankcase 14.
[0022]
The cylinder head 15 has an intake port 16 and an exhaust port 17 for each cylinder 11. Each intake port 16 is provided with an intake valve 161 driven by an intake cam IC to open and close the intake port 16, and each exhaust port 17 is driven by an exhaust cam EC to open and close the exhaust port 17. An exhaust valve 171 is provided. In addition to the above, a spark plug 31 for spark ignition is arranged on the cylinder head 15 at a position corresponding to each cylinder 11.
[0023]
In the intake-side cam IC (intake-side camshaft), the phase of the intake-side camshaft with respect to the crankshaft is displaced to delay the opening timing and closing timing of the intake valve 161 with respect to the normal timing (advance angle) ( A variable valve mechanism 25 (retarded) is provided. The variable valve mechanism 25 displaces the camshaft by an actuator 26 such as a motor or a hydraulic control valve. The variable valve mechanism 25 includes not only a mechanism for changing the valve timing but also a mechanism for changing the operating angle and the valve lift. In this embodiment, any variable valve mechanism may be used as long as the closing timing of the intake valve 161 can be delayed. Further, the intake valve 161 may be directly driven by an actuator.
[0024]
A branch end of an intake pipe 18 is connected to each intake port 16, and a branch end of an exhaust pipe (exhaust manifold) 19 is connected to each exhaust port 17. An intake control valve 30 for controlling the amount of intake air flowing into the combustion chamber is arranged in the intake pipe 19.
[0025]
In the middle of the intake pipe 18 and the exhaust pipe 19, a supercharger 28 for compressing intake air by an exhaust gas flow flowing through the exhaust pipe 19 is provided. The supercharger 28 is provided with a wastegate valve 281 capable of setting a supercharging pressure to an arbitrary value. When the wastegate valve 281 is opened, the exhaust gas bypasses the exhaust-side turbine of the supercharger 28 and is discharged into the atmosphere, so that the supercharger 28 does not operate. In the intake pipe 18, an intercooler (cooler) for cooling the supercharged intake air is disposed downstream of the supercharger 28. The supercharger 28 includes not only a device that compresses intake air using an exhaust gas flow but also a device that is mechanically driven by power from a crankshaft to compress intake air.
[0026]
Each intake port 16 is provided with a fuel injection valve IJ. That is, the internal combustion engine 10 used in the present embodiment is a port injection type internal combustion engine. Each fuel injection valve IJ is supplied with fuel via a fuel delivery pipe FD.
[0027]
The control unit 40 has an arithmetic processing function, a map, a storage function for storing programs, and the like. Various sensors such as an accelerator position sensor 50 for detecting the depression amount of an accelerator pedal, a vehicle speed sensor 51 for detecting a vehicle speed, and a crank position sensor 52 for detecting an engine speed are connected to the control unit 40. Signals from various sensors that detect the operating state of the vehicle are input. The fuel injection valve IJ, the actuator 21 of the variable compression ratio mechanism 20, the actuator 26 of the variable valve mechanism 25, the waste gate valve 281, the intake control valve 30, and the ignition plug 31 are connected to the control unit 40. The valve opening / closing timing of 161, mechanical compression ratio, on / off of supercharging, fuel injection timing, ignition timing, intake air amount, etc. are appropriately controlled.
[0028]
An internal combustion engine operation control process executed by the internal combustion engine control device according to the present embodiment will be described with reference to FIGS. FIG. 2 is a flowchart showing a processing routine executed in the operation control processing of the internal combustion engine in the present embodiment. FIG. 3 is an explanatory diagram showing an example of a map for determining the load region of the internal combustion engine 10 based on the required torque and the engine speed. FIG. 4 is an explanatory diagram showing load-specific control conditions set according to the determined load area. FIG. 5 is an explanatory diagram showing a change in the valve closing timing of the intake valve. FIG. 6 is an explanatory diagram illustrating a characteristic line representing the relationship between the fuel efficiency and the torque in the low, medium, and high load regions, for explaining the advantages of the present embodiment over the conventional control. FIG. 7 is an explanatory diagram showing a comparison between the fuel efficiency and the torque of the present embodiment and the conventional control, particularly in the medium load region. FIG. 8 is an explanatory diagram schematically showing a change in the compression ratio, a change in the mechanical compression ratio, and a change in the actual compression ratio due to the intake valve timing in the transition from the medium load region to the high load region in the present embodiment. is there.
[0029]
The operation control process of the internal combustion engine will be described with reference to FIG. This processing routine is repeatedly executed at predetermined time intervals. The control unit 40 detects a required torque based on the amount of depression of the accelerator pedal detected by the accelerator position sensor 50 (step S100), and converts the calculated required torque and the engine speed detected from the crank position sensor into parameters. Is determined from the map shown in FIG. 3 (step S110).
[0030]
When the control unit 40 determines that the operating load of the internal combustion engine 10 is in the low load region, the control unit 40 sets the compression ratio, the intake valve closing timing, and the supercharging state to the low load region condition shown in FIG. S120). That is, the mechanical compression ratio is set high, the closing timing of the intake valve is retarded as shown in FIG. 5, and supercharging is not performed. The control unit 40 transmits a drive signal to the actuator 21 to increase the mechanical compression ratio by bringing the cylinder block 12 and the crankcase 14 into close contact with each other, and transmits a drive signal to the actuator 26 to The closing timing is retarded from the normal timing, and a drive signal is transmitted to the wastegate valve 281 to open the wastegate valve 281 (step S130).
[0031]
As a result, the pumping loss is reduced by the late closing of the intake valve 161 and the mechanical compression ratio is set high, so that the fuel efficiency can be reduced (fuel efficiency can be reduced) as shown in FIG.
[0032]
When the control unit 40 determines that the operating load of the internal combustion engine 10 is in the medium load region, the control unit 40 sets the compression ratio, the intake valve closing timing, and the supercharging state to the medium load region conditions shown in FIG. S140). That is, the mechanical compression ratio is set high, the valve closing timing of the intake valve is retarded as shown in FIG. 5, and supercharging is performed. The control unit 40 transmits a drive signal to the actuator 21 to increase the mechanical compression ratio by bringing the cylinder block 12 and the crankcase 14 into close contact with each other, and transmits a drive signal to the actuator 26 to The valve closing timing is retarded from the normal timing, and a drive signal is transmitted to the wastegate valve 281 to close the wastegate valve 281 (step S150).
[0033]
In the control device for an internal combustion engine according to the present embodiment, the mechanical compression ratio is set high in the medium load region, the intake valve 161 is closed slowly, and supercharging is performed (this embodiment: L1 in FIG. 6). When the compression ratio is set low, the intake valve 161 is closed early (normal timing), and the supercharging is not executed (conventional control: L2 in FIG. 6), the fuel consumption rate is reduced (fuel consumption reduction). Can be planned. The medium load region is, for example, a load region in which the internal combustion engine 10 can output about １／ of the maximum torque that can be output when the supercharger 28 operates.
[0034]
That is, according to the present embodiment, since the degree of expansion is increased by setting the mechanical compression ratio high, the pressure obtained by combustion of the air-fuel mixture is efficiently transmitted to the piston (reduction of the loss of combustion pressure). ), The fuel efficiency can be improved as compared with the case where the mechanical compression ratio is low. Further, since the intake valve 161 is closed late, as compared with the case where the intake valve 161 is closed at a normal timing (advance angle), the intake air amount is reduced, so that the intake valve 161 is delayed as indicated by a black dot on the characteristic line L1 in FIG. Although only the angular torque can be output, the advanced torque (L2 in FIG. 7) when the valve closing timing of the intake valve 161 is advanced (L2 in FIG. 7) by supplementing the reduced intake air amount by supercharging. The same torque as that of the black spot can be obtained.
[0035]
Generally, when the mechanical compression ratio is high, the occurrence of knocking due to supercharging poses a problem. In this embodiment, however, the closing timing of the intake valve 161 is delayed by delaying the closing timing of the intake valve 161. The compression ratio (compression ratio from when the intake valve 161 is closed until the piston 13 reaches the compression top dead center) determined by the timing is lowered, and the actual compression ratio is lowered to increase the temperature of the air-fuel mixture (intake) due to compression. And the intake air compressed by the supercharger 28 is cooled by the intercooler 29. As a result, an increase in the temperature of the air-fuel mixture before ignition is suppressed, and knocking can be suppressed. The actual compression ratio means the actual compression ratio in the cylinder 11 determined by the closing timing of the intake valve 161 and the mechanical compression ratio.
[0036]
Therefore, the same torque as that obtained by the conventional control can be obtained with lower fuel consumption.
[0037]
When the control unit 40 determines that the operating load of the internal combustion engine 10 is in the high load region, the control unit 40 sets the compression ratio, the intake valve closing timing, and the supercharging state to the high load region condition shown in FIG. S160). That is, the mechanical compression ratio is set low, the valve closing timing of the intake valve is advanced as shown in FIG. 5, and supercharging is performed. The control unit 40 sends a drive signal to the actuator 21 to lower the mechanical compression ratio by separating the cylinder block 12 and the crankcase 14, and sends a drive signal to the actuator 26 to The closing timing is changed to the advance timing, which is the normal timing, and a drive signal is transmitted to the wastegate valve 281 to close the wastegate valve 281 (step S170).
[0038]
When switching from the medium load range to the high load range, the control unit 40 switches the valve closing timing of the intake valve 161 (from the retard angle to the advanced angle) and switches the mechanical compression ratio of the internal combustion engine 10 (from the high compression ratio to the low At the same time, the actual compression ratio at the time of transition from the medium load region to the high load region is kept constant as shown in FIG.
[0039]
In the control device for an internal combustion engine according to the present embodiment, the mechanical compression ratio is set low in the high load region, the intake valve 161 is closed early, and supercharging is performed (this embodiment: L1 in FIG. 6). When the compression ratio is set low, the intake valve 161 is closed slowly (normal timing), and supercharging is performed (conventional control: L2 in FIG. 6), the fuel efficiency is reduced (fuel efficiency is reduced). Greater torque can be obtained.
[0040]
That is, in the conventional control, the valve closing timing of the intake valve 161 is retarded, so that a further output torque is obtained by the supercharger from the retarding torque indicated by the black dot on L3 in FIG. 7 (L3 in FIG. 7). ), The achievable output torque was small. On the other hand, in the present embodiment, as indicated by the characteristic line L4 in FIG. 7, the valve closing timing of the intake valve 161 is advanced (normal timing). It is possible to obtain a torque (middle black spot on the characteristic line L4), and it is possible to obtain a larger torque by using a supercharger.
[0041]
When the execution of the condition corresponding to the load condition ends, the control unit 40 executes the operation control of the internal combustion engine 10 under the executed condition (step S180), and ends the processing routine. Specifically, control of the opening angle of the intake valve 30, control of the fuel injection timing, and control of the ignition timing are executed in accordance with the operating state (load) of the internal combustion engine 10.
[0042]
As described above, according to the control apparatus for an internal combustion engine according to the present embodiment, the mechanical compression ratio is set high in the medium load region, the intake valve 161 is closed slowly, and supercharging is performed. In comparison, the fuel efficiency in the middle load region can be improved. In the high load range, the mechanical compression ratio is set low, the intake valve 161 is closed early, and supercharging is performed. Therefore, the output torque can be increased at the same fuel efficiency as in the conventional control.
[0043]
Further, according to the control device for the internal combustion engine according to the present embodiment, the actual compression ratio at the time of transition from the medium load region to the high load region is kept constant, so that it is possible to substantially expand the medium load region, The fuel efficiency resulting from the ratio can be improved.
[0044]
-Other examples:
In the above-described embodiment, the cylinder compression / contraction type in which the cylinder block 12 moves with respect to the crankcase 14 has been described as an example of the variable compression ratio mechanism 20. In addition, for example, a joint portion is provided in the middle of the piston connecting rod. Alternatively, an intermediate bent connecting rod type that changes the position of the top dead center of the piston may be used. That is, if the variable compression mechanism includes a mechanism capable of changing the mechanical compression ratio (geometric compression ratio) of the internal combustion engine 10, the fuel efficiency in the medium load region is combined with the variable valve mechanism 25 and the supercharger 28 according to the above embodiment. Effects such as improvement of performance and increase of output torque in a high load region can be obtained.
[0045]
As described above, the control device for an internal combustion engine according to the present invention has been described based on some examples. However, the above-described embodiment is for facilitating the understanding of the present invention. There is no limitation. The present invention can be modified and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating a schematic configuration of a control device for an internal combustion engine according to an embodiment.
FIG. 2 is a flowchart showing a processing routine executed in an operation control process of the internal combustion engine in the embodiment.
FIG. 3 is an explanatory diagram showing an example of a map for determining a load region of the internal combustion engine 10 based on a required torque and an engine speed.
FIG. 4 is an explanatory diagram showing load-specific control conditions set according to a determined load area.
FIG. 5 is an explanatory diagram showing a change in a valve closing timing of an intake valve.
FIG. 6 is an explanatory diagram illustrating a characteristic line representing a relationship between a fuel consumption rate and a torque in a low, middle, and high load region, illustrating an advantage of the present embodiment over conventional control.
FIG. 7 is an explanatory diagram showing a comparison between fuel efficiency and torque in the present embodiment and the conventional control, particularly in a medium load region.
FIG. 8 is an explanatory diagram schematically showing a change in a compression ratio, a change in a mechanical compression ratio, and a change in an actual compression ratio due to intake valve timing when shifting from a medium load region to a high load region in the present embodiment. It is.
[Explanation of symbols]
Reference Signs List 10 internal combustion engine 11 cylinder 12 cylinder block 13 piston 14 crankcase 15 cylinder head 16 intake port 161 intake valve 17 exhaust port 171 exhaust valve 18 intake pipe 19 exhaust pipe 20 variable compression Ratio mechanism 21 Actuator 25 Variable valve mechanism 26 Actuator 28 Supercharger 281 Waste gate valve 29 Intercooler 30 Intake control valve 31 Boost pump 32 Spark plug 40 Control unit 50 Accelerator opening sensor 51 ... speed sensor 52 ... crank position sensor IC ... intake side cam EC ... exhaust side cam IJ ... fuel injection valve (injector)
FD: Fuel delivery pipe

Claims

A control device for an internal combustion engine having an intake valve for communicating or shutting off the inside of a cylinder of the internal combustion engine and the atmosphere,
A variable valve mechanism for changing the closing timing of the intake valve;
A variable compression ratio mechanism that changes a mechanical compression ratio of the internal combustion engine,
A supercharging mechanism for supplying compressed intake air into a cylinder of the internal combustion engine,
Required torque detecting means for detecting a required torque for the internal combustion engine,
When the detected required torque is in the middle load range, the closing timing of the intake valve is delayed by the variable valve operating mechanism, and the mechanical compression ratio of the internal combustion engine is increased by the variable compression ratio mechanism. Operation control means for operating a supercharging mechanism to supply compressed intake air into a cylinder of the internal combustion engine.

The control device for an internal combustion engine according to claim 1 further includes:
A control device for an internal combustion engine including a cooler for reducing the temperature of compressed intake air introduced into a cylinder of the internal combustion engine from the supercharging mechanism.

3. The control device for an internal combustion engine according to claim 1, wherein in the medium load region, a torque that is about １／ of a maximum torque output by the internal combustion engine when the supercharging mechanism is operating is required as a required torque. 4. A control device for an internal combustion engine, which is a load region to be used.

The control device for an internal combustion engine according to claim 1,
When the detected required torque is in a high load area where the load is larger than the medium load area, the operation control means advances the valve closing timing of the intake valve by the variable valve mechanism, and An operation control device for an internal combustion engine that lowers a mechanical compression ratio of the internal combustion engine by a ratio mechanism and operates the supercharging mechanism to supply compressed intake air into a cylinder of the internal combustion engine.

A control device for an internal combustion engine,
A supercharging mechanism,
A variable valve mechanism for changing at least the closing timing of the intake valve;
A variable compression ratio mechanism for changing the mechanical compression ratio of the internal combustion engine,
Required torque detecting means for detecting a required torque for the internal combustion engine,
When the detected required torque is in the first load region, the closing timing of the intake valve is retarded by the variable valve operating mechanism, and mechanical compression of the internal combustion engine is performed by the variable compression ratio mechanism. If the detected required torque is in a second load region that is larger than the first load region without increasing the ratio and performing supercharging by the supercharging mechanism, The valve closing timing of the intake valve is retarded, the mechanical compression ratio of the internal combustion engine is increased by the variable compression ratio mechanism, the supercharging is performed by the supercharging mechanism, and the detected required torque is reduced by the second load. When in a third load region that is larger than the region, the valve closing timing of the intake valve is advanced by the variable valve mechanism, and the mechanical compression ratio is reduced by the variable compression ratio mechanism to the internal combustion engine. The supercharging mechanism According control apparatus for an internal combustion engine and a driving control means for performing supercharging.

The control device for an internal combustion engine according to claim 5,
The operation control means controls the variable valve mechanism and the variable compression ratio mechanism to keep the actual compression ratio of the internal combustion engine constant when shifting from the second load area to the third load area. Control device for an internal combustion engine.

The control device for an internal combustion engine according to claim 6,
The operation control means advances the valve closing timing of the intake valve by the variable valve mechanism, and lowers the mechanical compression ratio of the internal combustion engine by the variable compression ratio mechanism, thereby realizing the actual compression ratio of the internal combustion engine. Control device for an internal combustion engine that keeps the pressure constant.

A control device for an internal combustion engine having an intake valve for communicating or shutting off the inside of a cylinder of the internal combustion engine and the atmosphere,
A variable valve mechanism for changing the closing timing of the intake valve;
A variable compression ratio mechanism that changes a mechanical compression ratio of the internal combustion engine,
A supercharging mechanism for supplying compressed intake air into a cylinder of the internal combustion engine,
A cooler that lowers the temperature of compressed intake air introduced into the cylinder of the internal combustion engine from the supercharging mechanism;
Required torque detecting means for detecting a required torque for the internal combustion engine,
When the detected required torque is in a high load region in which a torque larger than about トルク of the maximum torque output by the internal combustion engine is required during the operation of the supercharging mechanism, the variable dynamic The closing timing of the intake valve is advanced by a valve mechanism, the mechanical compression ratio of the internal combustion engine is reduced by the variable compression ratio mechanism, and the intake air compressed into the cylinder of the internal combustion engine by operating the supercharging mechanism An operation control device for an internal combustion engine, the operation control device comprising: