JP3601365B2

JP3601365B2 - Engine electromagnetic valve control device

Info

Publication number: JP3601365B2
Application number: JP22368199A
Authority: JP
Inventors: 真樹鳥海
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1999-08-06
Filing date: 1999-08-06
Publication date: 2004-12-15
Anticipated expiration: 2019-08-06
Also published as: JP2001050065A

Description

【０００１】
【発明の属する技術分野】
本発明は、吸・排気弁を半開位置に付勢するスプリングと、吸・排気弁を開弁方向に吸着して開弁保持させる開弁用電磁石及び吸・排気弁を閉弁方向に吸着して閉弁保持させる閉弁用電磁石と、を備えたエンジンの電磁動弁制御装置に関する。
【０００２】
【従来の技術】
この種の電磁動弁装置としては、一対のスプリングにより半開位置に付勢される弁体（吸・排気弁) を、該弁体に連係したアーマチャに電磁力を作用させて、開弁用電磁石又は閉弁用磁石に吸着することにより、全開位置又は全閉位置に保持する構造がある（特開平７−３３５４３７号参照）。
【０００３】
【発明が解決しようとする課題】
しかしながら、極低温時（−３０°Ｃ程度）は、始動後エンジン温度がまだ低いときには、潤滑油の粘性の増加によるフリクションの増大により、弁体作動に要する電磁力が増大し、消費電力が大きくなってしまい、該開閉制御の継続により、バッテリの上がりを生じるおそれもある。
【０００４】
また、前記フリクションの増大により、弁体が全閉位置から全開位置まで移動する時間及び全開位置から全閉位置まで移動する時間が増大して、開弁期間が圧縮行程まで長引くこととなって実質的に制御不能となってしまう可能性もあった。
本発明は、このような従来の課題に着目してなされたもので、開閉制御方式を切り換えることにより、上記課題を解決したエンジンの電磁動弁装置を提供することを目的とする。
【０００５】
【課題を解決するための手段】
このため、請求項１に係る発明は、
吸・排気弁を半開位置に付勢するスプリングと、吸・排気弁を開弁方向に吸着して開弁保持させる開弁用電磁石及び吸・排気弁を閉弁方向に吸着して閉弁保持させる閉弁用電磁石と、を備えたエンジンの電磁動弁制御装置において、
エンジン潤滑油の粘性状態を判定する潤滑油粘性状態判定手段と、
前記判定されたエンジン潤滑油の粘性状態に基づいて、前記開弁用電磁石と閉弁用電磁石とを通電制御して吸・排気弁を開閉する第１制御と、閉弁用電磁石のみを通電制御して吸・排気弁を開閉する第２制御とを切り換える第１制御切換手段と、
前記第１制御中に当該電磁動弁の可動部の速度を検出し、半開位置付近での検出速度が所定値未満のときに該第１制御から前記第２制御に切り換える第２制御切換手段と、
を含んで構成したことを特徴とする。
【０００６】
請求項１に係る発明によると、
潤滑油粘性状態判定手段により、エンジン潤滑油の粘性状態が判定され、第１制御切換手段は、エンジン潤滑油の粘性が通常のときは、開弁用電磁石と閉弁用磁石とを通電制御して、開弁時には吸・排気弁を全開とし閉弁時には全閉とする第１制御を行なわせ、エンジン潤滑油の粘性が大きく吸・排気弁動作のフリクションが大きいときは閉弁用電磁石のみを通電制御して、開弁時にはスプリングの付勢力によって吸・排気弁を半開とし閉弁時には閉弁用電磁石を通電して全閉とする第２制御を行なわせる。
【０００７】
これにより、吸・排気弁動作のフリクションが大きいときは閉弁用電磁石のみを通電するため、消費電力を節減できバッテリの上がりを防止できるとともに、弁体の移動が全閉位置から半開位置までの移動と半開位置から全閉位置までの移動ですむため、開弁期間の増大を回避でき、吸・排気弁の開閉制御によってエンジン運転を確保できる。
【０００８】
また、第２制御切換手段により、第１制御中に電磁動弁のアーマチャや弁体等の可動部の速度が検出され、半開位置付近での検出速度が所定値未満のときには、該第１制御から前記第２制御に切り換えられる。
このようにすれば、潤滑油粘性状態判定手段の判定誤差やバラツキ等によりフリクションが大きい状態で第１制御が行なわれた場合には、可動部の速度が大きく減衰してスプリングの付勢力でバランスする半開位置近傍で殆ど停止してしまうので、この速度状態を検出して前記第２制御に切り換えることにより、このような場合でも消費電力を節減し、バッテリの上がりを防止しつつ、吸・排気弁の開閉制御によってエンジン運転を可能とする。
【０００９】
また、請求項２に係る発明は、
吸・排気弁を半開位置に付勢するスプリングと、吸・排気弁を開弁方向に吸着して開弁保持させる開弁用電磁石及び吸・排気弁を閉弁方向に吸着して閉弁保持させる閉弁用電磁石と、を備えたエンジンの電磁動弁制御装置において、
エンジン潤滑油の粘性状態を判定する潤滑油粘性状態判定手段と、
前記判定されたエンジン潤滑油の粘性状態に基づいて、前記開弁用電磁石と閉弁用電磁石とを通電制御して吸・排気弁を開閉する第１制御と、閉弁用電磁石のみを通電制御して吸・排気弁を開閉する第２制御とを切り換える第１制御切換手段と、
前記第２制御中に電磁動弁の可動部の速度を検出し、半開位置付近での検出速度が所定値以上となったときに該第２制御から前記第１制御に切り換える第３制御切換手段と、
を含んで構成したことを特徴とする。
【００１０】
請求項２に係る発明によると、
第３制御切換手段により、第２制御中に電磁動弁のアーマチャや弁体等の可動部の速度が検出され、半開位置付近での検出速度が所定値以上となったときには、該第２制御から前記第１制御に切り換えられる。
このようにすれば、潤滑油粘性状態判定手段の判定誤差やバラツキ等によりフリクションが通常であるにも拘わらず第２制御が行なわれた場合には、可動部は半開位置近傍で停止することなく開弁方向へ移動するため、この速度状態を検出して前記第１制御に切り換えることにより、十分小さな消費電力で吸・排気弁を開閉制御することができ、十分大きな出力でエンジンを運転することができる。
【００１１】
また、請求項３に係る発明は、
前記潤滑油粘性状態判定手段は、エンジン潤滑油温度を検出してエンジン潤滑油の粘性状態を判定することを特徴とする。
請求項３に係る発明によると、
エンジン潤滑油温度とエンジン潤滑油の粘性状態とは密接な相関があり、潤滑油温度が低いときは粘性が大きくなるので、該エンジン潤滑油温度の検出によりエンジン潤滑油の粘性状態を判定する。
【００１２】
これにより、エンジン潤滑油の粘性状態を高精度に判定できる。
また、請求項４に係る発明は、
前記潤滑油粘性状態判定手段は、エンジン冷却水温度を検出してエンジン潤滑油の粘性状態を判定することを特徴とする。
請求項４に係る発明によると、
エンジン冷却水温度とエンジン潤滑油温度とは、正の相関を有しているので、エンジン冷却水温度を検出してエンジン潤滑油温度を推定し、さらにはエンジン潤滑油の粘性状態を推定して判定する。
【００１３】
これにより、エンジン制御用に一般的に装着されている水温センサを利用して、簡便かつ低コストにエンジン潤滑油の粘性状態を判定できる。
また、請求項５に係る発明は、
前記潤滑油粘性状態判定手段は、エンジン潤滑油圧力を検出してエンジン潤滑油の粘性状態を判定することを特徴とする。
【００１４】
請求項５に係る発明によると、
エンジン潤滑油圧力とエンジン潤滑油の粘性状態とは相関があり、潤滑油圧力が高いときは粘性が大きくなるので、該エンジン潤滑油圧力の検出によりエンジン潤滑油の粘性状態を判定する。
これにより、エンジン潤滑油の粘性状態を精度良く判定できる。
【００１５】
【発明の実施の形態】
以下、本発明の実施形態を図に基づいて説明する。
本発明の一実施形態のシステム構成を示す図１において、エンジン１には、弁駆動装置２により開閉を電子制御される吸気弁３及び排気弁４が装着されている。各気筒の吸気ポート５には、燃料噴射弁６が装着され、燃焼室７には点火栓８及び点火コイル９が装着されている。また、エンジン本体には、各気筒の基準クランク角で基準信号を出力すると共に微小クランク角毎に単位角信号を出力するクランク角センサ１０、エンジン冷却水温度を検出する水温センサ１１が装着され、吸気通路１２の上流部には、吸入空気流量を検出するエアフロメータ１３、排気通路１４には、排気中の酸素濃度等の検出を介して空燃比を検出する空燃比センサ１５が装着されている。
【００１６】
前記各種センサ類からの検出信号はコントロールユニット１６に入力され、コントロールユニット１６は、これらの検出信号に基づいて前記燃料噴射弁６に燃料噴射信号を出力して燃料噴射制御を行い、前記点火コイル９に点火信号を出力して点火制御を行い、更に、前記弁駆動装置に弁駆動信号を出力して吸気弁３及び排気弁４の開閉を制御する。また、後述する吸・排気弁の初期化のためにエンジン潤滑油の粘性状態を判定する手段として、油温センサ１７が設けられ、該油温センサ１７からの検出信号もコントロールユニット１６に入力される。
【００１７】
ここで、前記吸気弁３及び排気弁４と、これらを駆動するための弁駆動装置２からなる電磁動弁装置のハードウエアについて、図２に基づいて説明する。図２において、シリンダヘッド１８に従来と同様の方法で、排気弁４は取り付けられている。即ち、シリンダヘッド１８に設けられるバルブガイド１９に、排気弁４のステム３１が摺動自由に挿通されており、ステム３１上端部には、バルブコッター等を介してアッパーシート３２が取り付けられ、該アッパーシート３２と、シリンダヘッド側のロアシートとの間に、排気弁４を閉弁方向に付勢する（自由長から所定量圧縮された）閉弁用スプリング３３が配設されている。
【００１８】
そして、排気弁４が全閉状態で、後述する閉弁用電磁石４３でアーマチャを吸着している状態において、前記ステム３１の上端部から、所定量離間して、言い換えれば所定のバルブクリアランスを持って、弁駆動装置２の可動軸４０が、前記ステム３１と同軸上に配設されるようになっている。
前記弁駆動装置２は、非磁性体製のハウジング４１と、前記可動軸４０に一体に設けられてハウジング４１内に摺動自由に収納されるアーマチャ４２と、該アーマチャ４２を磁気吸引可能にアーマチャ４２の上面に対向する位置でハウジング４２内に固定配置される閉弁用電磁石４３と、該アーマチャ４２を磁気吸引して排気弁４を開弁保持可能にアーマチャ４２の下面に対向する位置でハウジング４１内に固定配置される開弁用電磁石４４と、排気弁４の開弁方向に向けてアーマチャ４２を付勢する開弁用スプリング４５と、を含んで構成されている。
【００１９】
そして、図３に示すように、閉弁用電磁石４３と開弁用電磁石４４とを共に消磁したときに、排気弁４は、半開位置となるように構成されており、この半開位置から前記閉弁用電磁石４３のみを通電励磁すると、アーマチャ４２は開弁用スプリング４５を押し縮める方向に閉弁用電磁石４３によって磁気吸引され、一方前記半開位置から開弁用電磁石４４のみを通電励磁すると、アーマチャ４２は閉弁用スプリング３３を押し縮めて排気弁４を開弁する方向に開弁用電磁石４４によって磁気吸引される。
【００２０】
また、図２、図３に二点鎖線で示すように、アーマチャ４２の変位（バルブリフト量）を検出するレーザー測距計等で構成されるリフト量センサ２１を配設し、後述するように該検出値に基づいて吸・排気弁の半開位置付近でのアーマチャ４２の速度を検出しつつ第１制御から第２制御への切換を確実に行われるようにする。
【００２１】
以上、排気弁４の開閉動作について示したが、吸気弁３についても全く同様の構成によって同様に動作する。但し、本発明は吸気弁、排気弁が共に電磁駆動されるものに限定されるものではなく、少なくとも一方の電磁駆動される弁に適用できるものである。
そして、始動前に、前記吸気弁３及び排気弁４を前記半開位置から、開弁（全開）位置または閉弁位置に保持する初期化を行った後、エンジン運転状態に応じて設定された開閉時期に開閉されるように開閉制御が行なわれる。
【００２２】
以下に、前記吸・排気弁の初期化後の開閉制御の各実施の形態を説明する。図４は、第１の実施の形態のフローを示す。ステップ１では、前記油温センサ１７によって検出されるエンジン潤滑油温度ｔｏを読み込む。
ステップ２では、検出された潤滑油温度ｔｏが設定温度ｔｏ０未満か否かを判定する。ここで、前記設定温度ｔｏ０は、これより低温であると潤滑油の粘性が大きすぎて吸・排気弁作動のフリクションが大きすぎるため、開弁用電磁石４４を通電して、吸・排気弁を全開まで開く第１制御を行なうと消費電力が大きくなりすぎ、該制御の継続によりバッテリの上がりを生じる可能性があり、かつ弁体の移動時間が長引いて実質的に開弁制御不能となる惧れがあるような、下限の温度に設定されている。
【００２３】
ステップ２で、潤滑油温度ｔｏが設定温度ｔｏ０以上と判定されたときは、開弁用電磁石４４を通電する第１制御を行なうことを決定し、ステップ３以降へ進む。
ステップ３では、第１制御における閉弁用電磁石４３及び開弁用電磁石４４の制御電流値Ｉ１、ステップ４では制御タイミングｔ１，ｔ２，ｔ３（図５参照、ｔ１：閉弁用電磁石の通電遮断から開弁用電磁石の通電開始までの時間、ｔ２：開弁用電磁石の通電時間、ｔ３：開弁用電磁石の通電遮断から閉弁用電磁石の通電開始までの時間）をそれぞれ潤滑油温度ｔｏに応じて推定される潤滑油の粘性に見合った値に設定する。
【００２４】
ステップ５では、前記設定値に従って通常の制御を実行する。
図５は、吸気弁３に対して前記第１制御を行なったときの通電制御及びアーマチャ４２（及びこれに連係する弁体）の変位を示す。
一方、ステップ２で、潤滑油温度ｔｏが設定温度ｔｏ０未満と判定されたときは、閉弁用電磁石のみを通電制御する第２制御を行なうことを決定し、ステップ６以降へ進む。
【００２５】
ステップ６では、閉弁時における閉弁用電磁石４３の制御電流値Ｉ２を、潤滑油温度ｔｏに応じて推定される潤滑油の粘性に見合った値に設定する。この場合も潤滑油温度ｔｏが低く粘性が大きいときほど吸・排気弁の作動フリクションが大きいので、制御電流値Ｉ２を大きい値に設定すればよい。
ステップ７では、閉弁用電磁石４３の制御タイミングｔ４（図６参照、ｔ４：閉弁用電磁石の通電遮断から通電開始までの時間）を潤滑油温度ｔｏに応じて推定される潤滑油の粘性に見合った値に設定する。潤滑油温度ｔｏが低く粘性が大きいときほど吸・排気弁の作動フリクションが大きく移動に時間がかかるので通電開始が早められるように、ｔ４を短い値に設定する。
【００２６】
ステップ８では、前記設定値に従って第２制御を実行する。上記ステップ２でエンジン潤滑油の粘性状態をあらわす潤滑油温度に応じて第１制御と第２制御との切換判定を行なう機能が第１制御切換手段に相当する。
図６は、吸気弁３に対して前記第２制御を行なったときの通電制御及びアーマチャ４２（及びこれに連係する弁体）の変位を示す。このようにすれば、通常は開弁時に開弁用電磁石４４を通電して弁体を全開まで開く制御を行なうが、極低温時にエンジン潤滑油の粘性が大くなりすぎたときには、開弁時に開弁用電磁石４４の通電を行なわず、スプリングの付勢力で半開とすることにより、消費電力を大きく節減できバッテリの上がりを防止できる。また、弁体をの移動期間が半減するため、開弁期間の増大を回避でき、吸・排気弁の開閉制御によってエンジン運転を確保できる。
【００２７】
エンジン運転開始後、エンジン温度の上昇と共に潤滑油温度が上昇し、設定温度ｔｏ０以上になると、前記ステップ２の判定により第１制御に切り換えられる。なお、吸気弁の半開状態では全開状態に比較すると吸気効率の減少は否めないが、前記第２制御が実行されるのは、エンジン始動後の比較的短い期間であり、必要最小限のフェールセーフ運転を確保するには十分である。
【００２８】
図４に戻って、ステップ５で、第１制御を開始後、ステップ３１でアーマチャ４２の変位ｘを読み込みつつ該変位ｘを微分処理して速度ｖを算出する。なお、コスト高となるが別途速度センサを設けて速度検出を行なうようにしてもよい。また、アーマチャ４２に連係する弁体の変位、速度を求める構成でもよい。
ステップ３２では、アーマチャ４２の変位ｘに基づいて吸・排気弁が半開位置近傍にあるか否かを判定する。
【００２９】
そして、半開位置近傍となったときにステップ３３へ進んで、アーマチャ４２の速度ｖが所定値ｖｏ未満であるか否かを判定し、ｖｏ未満でないときには、このまま第１制御を継続するが、ｖｏ未満と判定されたときには、吸・排気弁のフリクションが大きすぎ第１制御を行なうことが好ましくないと判断し、ステップ６へ進んで第２制御に切り換える。即ち、前記開弁用電磁石４４の通電は行なわれず、前記閉弁用電磁石４３の通電遮断後、設定時間ｔ４の経過後に閉弁用電磁石４４の通電を開始し、制御電流値Ｉ２に制御して閉弁する。
【００３０】
このようにすれば、エンジン潤滑油の粘性状態の検出に誤差やバラツキ等があって、第１制御を実質的に行なえない場合が発生したときには、第２制御に切り換えることができる。
なお、前記第２制御に切り換え後、潤滑油の粘性減少によって、前記半開付近におけるアーマチャ４２の速度ｖが所定値ｖｏ以上となった場合には、前記ステップ３３の判定がＹＥＳとなって第１制御に戻されるが、ハンチング防止のため、一旦第２制御に切り換えられた後に、ステップ３３で速度判定する場合には、判定用の速度（閾値）をｖｏより少し大きめの値に設定してヒステリシスを持たせるのがよい。
【００３１】
上記第１の実施の形態では、エンジン潤滑油の粘性状態を該粘性状態に密接に相関する潤滑油温度を検出して判定する構成としたため、高精度な制御切換判定を行なうことができる。
一方、エンジン潤滑油と正の相関を有するエンジン冷却水温度を検出することにより、エンジン潤滑油の粘性状態を推定で判定することもでき、精度では潤滑油温度を検出する方が勝るが、他のエンジン制御に必須で必ず装着される前記水温センサ１１の検出値を流用することができるため、低コストに実施できる。
【００３２】
図７は、該水温センサ１１により検出されるエンジン冷却水温度を用いた初期化制御を行なう第２の実施の形態のフローを示す。
ステップ１１で、水温センサ１１によって検出されるエンジン冷却水温度ｔｗを読み込み、ステップ１２で、検出された冷却水温度ｔｗが設定温度ｔｗ０未満か否かを判定する。ここで、前記設定温度ｔｗ０は、冷却水温度がこの温度ｔｗ０のときにエンジン潤滑油の温度が前記設定温度ｔｏ０になると推定されるときの温度に設定されている。したがって、エンジン冷却水温度ｔｗが前記設定温度ｔｗ０以上のときはステップ１３〜ステップ１６へ進んで第１制御を行ない、設定温度ｔｗ０未満のときはステップ１７〜ステップ１９へ進んで第２制御を行なう。
【００３３】
また、エンジン潤滑油圧力もエンジン潤滑油の粘性状態とは相関があり、潤滑油圧力が高いときは粘性が大きくなるので、該エンジン潤滑油圧力を検出することによってもエンジン潤滑油の粘性状態を検出することができる。潤滑油粘性状態の検出精度としては、潤滑油温度を検出する場合と、冷却水温度を検出する場合との中間位と予測されるが、油温センサの配設が難しい場合や、別の制御で油圧検出を行なうため、油圧センサを備えている場合などは有利である。ステップ３１〜ステップ３３については、第１の実施形態と同様であるので説明を省略する（以下の実施形態でも同様）。
【００３４】
前記エンジン潤滑油圧力の検出により、エンジン潤滑油の粘性状態を検出して制御の切り換えを行なう第３の実施の形態としては、図１に一点鎖線で示すように、エンジン潤滑油圧力を検出する油圧センサ２０を設け、該油圧センサ２０の検出値を用いて、図８に示したフローで制御を行なう。
図８のステップ２１では、油圧センサ２０によって検出されるエンジン潤滑油圧力ｐｏを読み込み、ステップ２２で、検出された潤滑油圧力ｐｏが設定圧力ｐｏ０より高いか否かを判定する。ここで、前記設定圧力ｐｏ０は、潤滑油圧力がこれより高圧であると潤滑油の粘性が大きすぎて吸・排気弁作動のフリクションが大きすぎるため、前記制御では消費電力が増大し、開弁期間も増大して制御不能となる可能性もある上限の圧力に設定されている。したがって、エンジン潤滑油圧力ｐｏが前記設定圧力ｐｏ０以下のときはステップ２３〜ステップ２６へ進んで第１制御を行ない、設定圧力ｐｏ０より高いときはステップ２７〜ステップ２９へ進んで第２制御を行なう。
【００３５】
次に、前記各実施形態のステップ３１〜ステップ３３同様に、制御の切換がより確実に行なわれるようにした第４の実施の形態について説明する。本実施の形態でも、前記リフト量センサ２１の検出値に基づいて吸・排気弁の半開位置付近でのアーマチャ４２の速度を検出しつつ図９のフローに示す制御を行なう。
図９において、ステップ１〜ステップ８は、図４の第１の実施の形態と同様である。本実施の形態では、ステップ８で第２制御を開始後、前記各実施の形態同様にステップ３１でアーマチャ４２の変位ｘの読み込み、速度ｖの算出を行ない、ステップ３２の判定で吸・排気弁が半開位置近傍となったときにステップ３３でアーマチャ４２の速度ｖが所定値ｖｏ未満であるか否かを判定し、ｖｏ未満のときには、このまま第２制御を継続するが、ｖｏ未満でないと判定されたときには、吸・排気弁のフリクションが減少したため第１制御を行なうべきと判断し、ステップ３へ進む。
【００３６】
このようにすれば、エンジン潤滑油の粘性状態の検出に誤差やバラツキ等があって、第１制御を行なえる状態になっているにも拘わらず第２制御が選択された場合には、速やかに第１制御に切り換えることができる。
また、前記第４の実施の形態のステップ１〜ステップ８の部分を、第２，第３の実施の形態と同様に、エンジン潤滑油の粘性状態の検出をエンジン冷却水温度、エンジン潤滑油圧力を検出して行なうようにしてもよい。
【図面の簡単な説明】
【図１】実施の形態におけるエンジンのシステム構成図。
【図２】実施の形態における電磁動弁装置の吸・排気弁閉弁状態時の構成を示す断面図。
【図３】同上電磁動弁装置の吸気弁半開状態時の構成を示す断面図。
【図４】第１の実施の形態における吸・排気弁の開閉制御を示すフローチャート。
【図５】吸気弁を通常制御により開閉したときの様子を示すタイムチャート。
【図６】吸気弁をフェールセーフ制御により開閉したときの様子を示すタイムチャート。
【図７】第２の実施の形態における吸・排気弁の開閉制御を示すフローチャート。
【図８】第３の実施の形態における吸・排気弁の開閉制御を示すフローチャート。
【図９】第４の実施の形態における吸・排気弁の開閉制御を示すフローチャート。
【符号の説明】
１エンジン
２弁駆動装置
３吸気弁
４排気弁
10 クランク角センサ
11 コントロールユニット
33 閉弁用スプリング
42 アーマチャ
43 閉弁用電磁石
44 開弁用電磁石
45 開弁用スプリング[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a spring for urging an intake / exhaust valve to a half-open position, an electromagnet for opening and holding the intake / exhaust valve in the valve opening direction to hold the valve open, and an intake / exhaust valve for attracting the intake / exhaust valve in a valve closing direction. And a valve closing electromagnet for holding the valve closed.
[0002]
[Prior art]
As this type of electromagnetic valve device, a valve element (intake / exhaust valve) urged to a half-open position by a pair of springs is operated by applying an electromagnetic force to an armature linked to the valve element to form a valve opening electromagnet. Alternatively, there is a structure in which a magnet is held at a fully open position or a fully closed position by being attracted to a valve-closing magnet (see Japanese Patent Application Laid-Open No. 7-335437).
[0003]
[Problems to be solved by the invention]
However, at extremely low temperatures (about −30 ° C.), when the engine temperature is still low after the start, the electromagnetic force required to operate the valve body increases due to an increase in friction due to an increase in the viscosity of the lubricating oil, resulting in a large power consumption. As a result, the continuation of the opening / closing control may cause the battery to rise.
[0004]
Further, due to the increase in the friction, the time required for the valve element to move from the fully closed position to the fully open position and the time required to move from the fully open position to the fully closed position are increased, and the valve opening period is prolonged to the compression stroke. There was also a possibility that it could become out of control.
The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide an electromagnetic valve device for an engine that solves the above problem by switching an open / close control method.
[0005]
[Means for Solving the Problems]
Therefore, the invention according to claim 1 is
A spring that urges the intake / exhaust valve to the half-open position, a valve-opening electromagnet that attracts the intake / exhaust valve in the valve opening direction and holds the valve open, and a valve that holds the intake / exhaust valve in the valve closing direction and holds the valve closed A valve closing electromagnet, and an electromagnetic valve control device for the engine comprising:
Lubricating oil viscosity state determining means for determining the viscous state of the engine lubricating oil;
Based on the determined viscosity state of the engine lubricating oil, the first control for energizing the valve-opening electromagnet and the valve-closing electromagnet to open and close the intake and exhaust valves, and energizing only the valve-closing electromagnet First control switching means for switching between the second control for opening and closing the intake / exhaust valve by switching
Second control switching means for detecting the speed of the movable portion of the electromagnetic valve during the first control, and switching from the first control to the second control when the detected speed near the half-open position is less than a predetermined value; ,
Is characterized by comprising.
[0006]
According to the first aspect of the invention,
The viscosity state of the engine lubricating oil is determined by the lubricating oil viscosity state determining means, and the first control switching means energizes and controls the valve opening electromagnet and the valve closing magnet when the engine lubricating oil viscosity is normal. When the valve is opened, the intake / exhaust valve is fully opened, and when the valve is closed, the first control is performed. When the viscosity of the engine lubricating oil is large and the friction of the intake / exhaust valve operation is large, only the valve closing electromagnet is used. When the valve is opened, a second control is performed in which the intake / exhaust valve is half-opened by the biasing force of the spring and the valve-closing electromagnet is energized and fully closed when the valve is closed.
[0007]
As a result, when the friction of the intake / exhaust valve operation is large, only the valve-closing electromagnet is energized, so that the power consumption can be reduced and the battery can be prevented from rising, and the valve body can be moved from the fully closed position to the half-open position. Since the movement and the movement from the half-open position to the fully-closed position are sufficient, an increase in the valve opening period can be avoided, and the engine operation can be ensured by controlling the opening and closing of the intake and exhaust valves.
[0008]
Further, the speed of the movable part such as the armature or valve body of the electromagnetic valve is detected by the second control switching means during the first control. When the detected speed near the half-open position is less than a predetermined value, the first control is performed. Is switched to the second control.
With this configuration, when the first control is performed in a state where the friction is large due to a determination error or a variation of the lubricating oil viscosity state determination unit, the speed of the movable unit is greatly attenuated, and the balance is established by the urging force of the spring. Since the vehicle almost stops near the half-open position, the speed state is detected and the control is switched to the second control. In such a case, the power consumption can be reduced, and the intake / exhaust air can be reduced while preventing the battery from rising. The engine can be operated by controlling the opening and closing of the valve.
[0009]
The invention according to claim 2 is
A spring that urges the intake / exhaust valve to the half-open position, a valve-opening electromagnet that attracts the intake / exhaust valve in the valve opening direction and holds the valve open, and a valve that holds the intake / exhaust valve in the valve closing direction and holds the valve closed A valve closing electromagnet, and an electromagnetic valve control device for the engine comprising:
Lubricating oil viscosity state determining means for determining the viscous state of the engine lubricating oil;
Based on the determined viscosity state of the engine lubricating oil, the first control for energizing the valve-opening electromagnet and the valve-closing electromagnet to open and close the intake and exhaust valves, and energizing only the valve-closing electromagnet First control switching means for switching between the second control for opening and closing the intake / exhaust valve by switching
Third control switching means for detecting the speed of the movable portion of the electromagnetic valve during the second control, and switching from the second control to the first control when the detected speed near the half-open position becomes a predetermined value or more. When,
Is characterized by comprising .
[0010]
According to the invention according to claim 2,
The third control switching means, the speed of the movable part, such as the armature and the valve body of the electromagnetic valve operating is detected during the second control, when the detected velocity of the near half-open position is equal to or greater than the predetermined value, the second control Is switched to the first control .
With this configuration, when the second control is performed in spite of the fact that the friction is normal due to the determination error or the variation of the lubricating oil viscosity state determination unit, the movable unit does not stop near the half-open position. By detecting this speed state and switching to the first control to move in the valve opening direction, the intake and exhaust valves can be opened and closed with sufficiently small power consumption, and the engine can be operated with a sufficiently large output. Can be.
[0011]
The invention according to claim 3 is:
The lubricating oil viscosity state determining means detects an engine lubricating oil temperature to determine a viscous state of the engine lubricating oil.
According to the invention according to claim 3 ,
There is a close correlation between the engine lubricating oil temperature and the viscosity state of the engine lubricating oil. When the lubricating oil temperature is low, the viscosity increases. Therefore, the viscous state of the engine lubricating oil is determined by detecting the engine lubricating oil temperature.
[0012]
Thereby, the viscous state of the engine lubricating oil can be determined with high accuracy.
The invention according to claim 4 is
The lubricating oil viscosity state determination means detects the engine cooling water temperature to determine the viscous state of the engine lubricating oil.
According to the invention of claim 4 ,
Since the engine cooling water temperature and the engine lubricating oil temperature have a positive correlation, the engine cooling water temperature is detected to estimate the engine lubricating oil temperature, and further, the viscosity state of the engine lubricating oil is estimated. judge.
[0013]
Thereby, the viscosity state of the engine lubricating oil can be determined simply and at low cost by using the water temperature sensor generally mounted for engine control.
The invention according to claim 5 is
The lubricating oil viscosity state determining means detects the engine lubricating oil pressure to determine the viscous state of the engine lubricating oil.
[0014]
According to the invention according to claim 5 ,
There is a correlation between the engine lubricating oil pressure and the viscosity state of the engine lubricating oil. When the lubricating oil pressure is high, the viscosity increases. Therefore, the viscous state of the engine lubricating oil is determined by detecting the engine lubricating oil pressure.
Thereby, the viscous state of the engine lubricating oil can be accurately determined.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1 showing a system configuration of an embodiment of the present invention, an engine 1 is provided with an intake valve 3 and an exhaust valve 4 whose opening and closing are electronically controlled by a valve driving device 2. A fuel injection valve 6 is mounted on an intake port 5 of each cylinder, and an ignition plug 8 and an ignition coil 9 are mounted on a combustion chamber 7. Further, the engine body is provided with a crank angle sensor 10 that outputs a reference signal at a reference crank angle of each cylinder and outputs a unit angle signal for each minute crank angle, and a water temperature sensor 11 that detects engine coolant temperature. An air flow meter 13 for detecting an intake air flow rate is mounted on an upstream portion of the intake passage 12, and an air-fuel ratio sensor 15 for detecting an air-fuel ratio through detection of an oxygen concentration or the like in exhaust gas is mounted on an exhaust passage. .
[0016]
Detection signals from the various sensors are input to a control unit 16, which outputs a fuel injection signal to the fuel injection valve 6 based on these detection signals to perform fuel injection control. An ignition signal is output to 9 and ignition control is performed. Further, a valve driving signal is output to the valve driving device to control opening and closing of the intake valve 3 and the exhaust valve 4. Further, an oil temperature sensor 17 is provided as means for determining the viscosity state of the engine lubricating oil for initialization of an intake / exhaust valve described later, and a detection signal from the oil temperature sensor 17 is also input to the control unit 16. You.
[0017]
Here, the hardware of the electromagnetic valve device including the intake valve 3 and the exhaust valve 4 and the valve driving device 2 for driving them will be described with reference to FIG . In FIG. 2 , the exhaust valve 4 is attached to the cylinder head 18 in the same manner as in the related art. That is, the stem 31 of the exhaust valve 4 is slidably inserted into the valve guide 19 provided on the cylinder head 18, and an upper seat 32 is attached to the upper end of the stem 31 via a valve cotter or the like. Between the upper seat 32 and the lower seat on the cylinder head side, a valve closing spring 33 for urging the exhaust valve 4 in the valve closing direction (compressed by a predetermined amount from a free length) is provided.
[0018]
When the exhaust valve 4 is fully closed and the armature is attracted by the valve-closing electromagnet 43 to be described later, the exhaust valve 4 is separated from the upper end of the stem 31 by a predetermined amount, in other words, has a predetermined valve clearance. The movable shaft 40 of the valve driving device 2 is arranged coaxially with the stem 31.
The valve driving device 2 includes a housing 41 made of a non-magnetic material, an armature 42 provided integrally with the movable shaft 40 and slidably housed in the housing 41, and an armature capable of magnetically attracting the armature 42. A valve closing electromagnet 43 fixedly disposed in the housing 42 at a position facing the upper surface of the armature 42; and a housing at a position facing the lower surface of the armature 42 so as to magnetically attract the armature 42 and hold the exhaust valve 4 open. A valve-opening electromagnet 44 fixed to the inside 41 and a valve-opening spring 45 for urging the armature 42 in the valve-opening direction of the exhaust valve 4 are included.
[0019]
As shown in FIG. 3 , when the valve closing electromagnet 43 and the valve opening electromagnet 44 are both demagnetized, the exhaust valve 4 is configured to be in a half-open position. When only the valve electromagnet 43 is energized and excited, the armature 42 is magnetically attracted by the valve closing electromagnet 43 in a direction to compress the valve opening spring 45. On the other hand, when only the valve opening electromagnet 44 is energized from the half-open position, the armature is energized. Reference numeral 42 is magnetically attracted by the valve-opening electromagnet 44 in a direction in which the valve-closing spring 33 is compressed to open the exhaust valve 4.
[0020]
Further, as shown by a two-dot chain line in FIGS. 2 and 3, a lift amount sensor 21 composed of a laser distance meter or the like for detecting the displacement (valve lift amount) of the armature 42 is provided, as will be described later. The switching from the first control to the second control is ensured while detecting the speed of the armature 42 near the half-open position of the intake / exhaust valve based on the detected value .
[0021]
Although the opening and closing operation of the exhaust valve 4 has been described above, the intake valve 3 operates in the same manner with the completely same configuration. However, the present invention is not limited to the case where both the intake valve and the exhaust valve are electromagnetically driven, but is applicable to at least one of the electromagnetically driven valves.
Before the start, the intake valve 3 and the exhaust valve 4 are initialized from the half-open position to the open (fully open) position or the closed position, and then opened and closed according to the engine operating state. Opening / closing control is performed so as to be opened and closed at the appropriate timing.
[0022]
Hereinafter, embodiments of the opening / closing control after the initialization of the intake / exhaust valve will be described. FIG. 4 shows a flow of the first embodiment. In step 1, the engine lubricating oil temperature to detected by the oil temperature sensor 17 is read.
In step 2, it is determined whether the detected lubricating oil temperature to is lower than the set temperature to0. Here, if the set temperature to0 is lower than this, since the viscosity of the lubricating oil is too large and the friction of the operation of the intake and exhaust valves is too large, the valve opening electromagnet 44 is energized to operate the intake and exhaust valves. If the first control that opens to the full open state is performed, the power consumption becomes too large, the battery may rise due to the continuation of the control, and the opening time of the valve body is prolonged, and the valve opening control may not be performed substantially. The temperature is set to the lower limit so that there is a problem.
[0023]
If it is determined in step 2 that the lubricating oil temperature to is equal to or higher than the set temperature to0, it is determined that the first control for energizing the valve opening electromagnet 44 is to be performed, and the process proceeds to step 3 and subsequent steps.
In step 3, the control current value I1 of the valve-closing electromagnet 43 and valve opening electromagnet 44 in the first control, step 4, the control timing t1, t2, t3 (see FIG. 5, t1: the current blocking valve closing electromagnet The time until the energization of the valve opening electromagnet is started, t2: the energization time of the valve opening electromagnet, and t3: the time from the energization cutoff of the valve opening electromagnet to the energization start of the valve closing electromagnet) according to the lubricating oil temperature to. To a value that matches the estimated viscosity of the lubricating oil.
[0024]
In step 5, normal control is executed according to the set value.
FIG. 5 shows the energization control and the displacement of the armature 42 (and the valve body associated therewith) when the first control is performed on the intake valve 3.
On the other hand, when it is determined in step 2 that the lubricating oil temperature to is lower than the set temperature to0, it is determined that the second control for controlling the energization of only the valve closing electromagnet is to be performed, and the process proceeds to step 6 and subsequent steps.
[0025]
In step 6, the control current value I2 of the valve-closing electromagnet 43 at the time of valve closing is set to a value corresponding to the viscosity of the lubricating oil estimated according to the lubricating oil temperature to. In this case as well, the lower the lubricating oil temperature to and the higher the viscosity, the greater the operating friction of the intake and exhaust valves, so the control current value I2 may be set to a large value.
In step 7, the control timing t4 of the valve-closing electromagnet 43 (see FIG. 6 , t4: the time from when the energization is cut off to when the energization is started) of the valve-closing electromagnet 43 is set to the lubricating oil viscosity estimated according to the lubricating oil temperature to. Set to a value that is appropriate. T4 is set to a short value so that the lower the lubricating oil temperature to and the higher the viscosity, the greater the operating friction of the intake / exhaust valve and the longer the movement, the earlier the start of energization.
[0026]
In step 8, the second control is executed according to the set value. The function of performing the switching determination between the first control and the second control according to the lubricating oil temperature indicating the viscous state of the engine lubricating oil in step 2 corresponds to first control switching means.
FIG. 6 shows the energization control and the displacement of the armature 42 (and the valve body associated therewith) when the second control is performed on the intake valve 3. By doing so, the valve opening electromagnet 44 is normally energized to open the valve body to the fully opened state when the valve is opened, but when the viscosity of the engine lubricating oil becomes too large at a very low temperature, the valve is opened. When the valve-opening electromagnet 44 is not energized and is half-opened by the biasing force of the spring, the power consumption can be greatly reduced and the battery can be prevented from rising. Further, since the moving period of the valve body is halved, an increase in the valve opening period can be avoided, and the engine operation can be ensured by controlling the opening and closing of the intake and exhaust valves.
[0027]
After the start of the engine operation, when the lubricating oil temperature rises with the rise of the engine temperature and becomes equal to or higher than the set temperature to0, the control is switched to the first control based on the determination in the step 2. Although the intake efficiency is unavoidably reduced in the half-open state of the intake valve compared to the fully-open state, the second control is executed only for a relatively short period after the engine is started, and the necessary fail-safe operation is performed. It is enough to secure driving .
[0028]
Returning to FIG. 4, after the first control is started in step 5, the displacement x of the armature 42 is read in step 31 while the displacement x is differentiated to calculate the velocity v in step 31. Although the cost is high, a speed sensor may be separately provided to detect the speed. Further, a configuration may be adopted in which the displacement and the speed of the valve body linked to the armature 42 are obtained.
In step 32, it is determined based on the displacement x of the armature 42 whether the intake / exhaust valve is near the half-open position.
[0029]
When the vehicle is near the half-open position, the process proceeds to step 33, where it is determined whether or not the speed v of the armature 42 is less than a predetermined value vo. If not, the first control is continued as it is. When it is determined that it is less than the predetermined value, it is determined that the friction of the intake / exhaust valve is too large and it is not preferable to perform the first control , and the process proceeds to step 6 to switch to the second control . That is, the energization of the valve-opening electromagnet 44 is not performed, and after the energization of the valve-closing electromagnet 43 is cut off, the energization of the valve-closing electromagnet 44 is started after a lapse of a set time t4, and the control current value I2 is controlled. Close the valve.
[0030]
With this configuration, when there is a case where the detection of the viscous state of the engine lubricating oil has an error or variation and the first control cannot be substantially performed, the control can be switched to the second control .
After the switching to the second control , if the speed v of the armature 42 near the half-open becomes equal to or higher than the predetermined value vo due to the decrease in the viscosity of the lubricating oil, the determination in the step 33 becomes YES and the first When the speed is determined in step 33 after temporarily switching to the second control in order to prevent hunting, the speed (threshold) for determination is set to a value slightly larger than vo and the hysteresis is returned. It is better to have
[0031]
In the first embodiment, the viscous state of the engine lubricating oil is determined by detecting the lubricating oil temperature that is closely correlated with the viscous state, so that a highly accurate control switching determination can be performed.
On the other hand, by detecting the engine coolant temperature that has a positive correlation with the engine lubricating oil, it is possible to estimate and determine the viscous state of the engine lubricating oil. Since the detection value of the water temperature sensor 11, which is indispensable and always attached to the engine control, can be used, the cost can be reduced.
[0032]
FIG. 7 shows a flow of a second embodiment for performing initialization control using the engine cooling water temperature detected by the water temperature sensor 11.
In step 11, the engine coolant temperature tw detected by the coolant temperature sensor 11 is read, and in step 12, it is determined whether the detected coolant temperature tw is lower than the set temperature tw0. Here, the set temperature tw0 is set to a temperature at which the temperature of the engine lubricating oil is estimated to reach the set temperature to0 when the coolant temperature is the temperature tw0. Therefore, when the engine coolant temperature tw is equal to or higher than the set temperature tw0, the process proceeds to steps 13 to 16 to perform the first control, and when the engine coolant temperature is lower than the set temperature tw0, the process proceeds to steps 17 to 19 to perform the second control . .
[0033]
Further, the engine lubricating oil pressure also has a correlation with the viscous state of the engine lubricating oil, and when the lubricating oil pressure is high, the viscosity increases. Therefore, by detecting the engine lubricating oil pressure, the viscous state of the engine lubricating oil is also determined. Can be detected. The detection accuracy of the lubricating oil viscosity state is expected to be intermediate between the case where the lubricating oil temperature is detected and the case where the cooling water temperature is detected. , Which is advantageous when a hydraulic pressure sensor is provided. Steps 31 to 33 are the same as those in the first embodiment, and a description thereof will be omitted (the same applies to the following embodiments).
[0034]
According to a third embodiment in which the control of the engine lubricating oil is switched by detecting the viscous state of the engine lubricating oil by detecting the engine lubricating oil pressure, the engine lubricating oil pressure is detected as shown by a dashed line in FIG. A hydraulic pressure sensor 20 is provided, and control is performed according to the flow shown in FIG. 8 using the detection value of the hydraulic pressure sensor 20.
In step 21 of FIG. 8, the engine lubricating oil pressure po detected by the oil pressure sensor 20 is read, and in step 22, it is determined whether the detected lubricating oil pressure po is higher than the set pressure po0. Here, when the set pressure po0 is higher than the lubricating oil pressure, the viscosity of the lubricating oil is too large and the friction of the operation of the intake / exhaust valve is too large. The period is set to an upper limit pressure that may increase and may become uncontrollable. Accordingly, when the engine lubricating oil pressure po is equal to or lower than the set pressure po0, the process proceeds to steps 23 to 26 to perform the first control, and when the engine lubricating oil pressure po is higher than the set pressure po0, the process proceeds to steps 27 to 29 to perform the second control. .
[0035]
Next, a description will be given of a fourth embodiment in which the control is more reliably switched as in steps 31 to 33 of the above embodiments. Also in the present embodiment, the control shown in the flow of FIG. 9 is performed while detecting the speed of the armature 42 near the half-open position of the intake / exhaust valve based on the detection value of the lift amount sensor 21.
9, steps 1 8 is similar to the first embodiment of FIG. In the present embodiment, after the second control is started in step 8, the displacement x of the armature 42 is read and the velocity v is calculated in step 31 similarly to the above embodiments, and the intake / exhaust valve is determined in step 32. Is closer to the half-open position, it is determined in step 33 whether or not the speed v of the armature 42 is less than a predetermined value vo. If it is less than vo, the second control is continued, but it is determined that it is not less than vo If so, it is determined that the first control should be performed because the friction between the intake and exhaust valves has decreased, and the routine proceeds to step 3.
[0036]
With this configuration, if the second control is selected in spite of an error or variation in the detection of the viscosity state of the engine lubricating oil and the first control can be performed, promptly Can be switched to the first control .
Also, the steps 1 to 8 of the fourth embodiment are replaced by the detection of the viscous state of the engine lubricating oil in the same manner as in the second and third embodiments. May be detected and performed.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram of an engine according to an embodiment.
FIG. 2 is a cross-sectional view illustrating a configuration of the electromagnetic valve device according to the embodiment when the intake and exhaust valves are closed.
FIG. 3 is a cross-sectional view showing a configuration of the electromagnetic valve device when the intake valve is half-opened;
FIG. 4 is a flowchart illustrating opening / closing control of intake / exhaust valves according to the first embodiment;
FIG. 5 is a time chart showing a state when an intake valve is opened and closed by normal control.
FIG. 6 is a time chart showing a state when the intake valve is opened and closed by fail-safe control.
FIG. 7 is a flowchart illustrating opening / closing control of intake / exhaust valves according to the second embodiment.
FIG. 8 is a flowchart illustrating opening / closing control of intake / exhaust valves according to the third embodiment.
FIG. 9 is a flowchart illustrating opening / closing control of intake / exhaust valves according to a fourth embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Engine 2 Valve drive 3 Intake valve 4 Exhaust valve
10 Crank angle sensor
11 Control unit
33 Valve closing spring
42 armature
43 Electromagnet for closing valve
44 Valve opening electromagnet
45 Valve opening spring

Claims

A spring that urges the intake / exhaust valve to the half-open position, a valve-opening electromagnet that attracts the intake / exhaust valve in the valve opening direction and holds the valve open, and a valve that holds the intake / exhaust valve in the valve closing direction and holds the valve closed A valve closing electromagnet, and an electromagnetic valve control device for the engine comprising:
Lubricating oil viscosity state determining means for determining the viscous state of the engine lubricating oil;
Based on the determined viscosity state of the engine lubricating oil, the first control for energizing the valve-opening electromagnet and the valve-closing electromagnet to open and close the intake and exhaust valves, and energizing only the valve-closing electromagnet First control switching means for switching between the second control for opening and closing the intake / exhaust valve by switching
Second control switching means for detecting the speed of the movable portion of the electromagnetic valve during the first control, and switching from the first control to the second control when the detected speed near the half-open position is less than a predetermined value; ,
An electromagnetic valve control device for an engine, comprising:

A spring that urges the intake / exhaust valve to the half-open position, a valve-opening electromagnet that attracts the intake / exhaust valve in the valve opening direction and holds the valve open, and a valve that holds the intake / exhaust valve in the valve closing direction and holds the valve closed A valve closing electromagnet, and an electromagnetic valve control device for the engine comprising:
Lubricating oil viscosity state determining means for determining the viscous state of the engine lubricating oil;
Based on the determined viscous state of the engine lubricating oil, the first control for energizing the valve-opening electromagnet and the valve-closing electromagnet to open and close the intake and exhaust valves, and energizing only the valve-closing electromagnet First control switching means for switching between the second control for opening and closing the intake and exhaust valves by switching
Third control switching means for detecting the speed of the movable portion of the electromagnetic valve during the second control, and switching from the second control to the first control when the detected speed near the half-open position becomes a predetermined value or more. When,
An electromagnetic valve control device for an engine, comprising:

3. The electromagnetic valve control device for an engine according to claim 1, wherein the lubricating oil viscosity state determining unit detects an engine lubricating oil temperature by detecting an engine lubricating oil temperature. 4.

3. The electromagnetic valve control device for an engine according to claim 1, wherein the lubricating oil viscosity state determining unit determines a viscous state of the engine lubricating oil by detecting an engine coolant temperature. 4.

3. The electromagnetic valve control device for an engine according to claim 1, wherein the lubricating oil viscosity state determining unit detects the lubricating oil pressure by detecting an engine lubricating oil pressure. 4.