JP3678092B2

JP3678092B2 - Intake control device for vehicle engine

Info

Publication number: JP3678092B2
Application number: JP34537699A
Authority: JP
Inventors: 尚夫川崎; 勝博荒井; 初雄永石
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1999-12-03
Filing date: 1999-12-03
Publication date: 2005-08-03
Anticipated expiration: 2019-12-03
Also published as: JP2001159328A

Description

【０００１】
【発明の属する技術分野】
本発明は、吸気バルブのバルブタイミングの制御によってエンジンの吸入空気量を目標吸入空気量に制御する構成の車両用エンジンの吸気制御装置に関し、詳しくは、吸気騒音の制御によって車室内の騒音を低減させる技術に関する。
【０００２】
【従来の技術】
従来、閉弁用電磁コイルと開弁用電磁コイルとを備え、吸気バルブや排気バルブを、前記電磁コイルによる電磁力で開閉駆動する構成の電磁駆動式バルブが知られている（特開平８−２０００２５号公報等参照）。
【０００３】
前記電磁駆動式のバルブであれば、バルブタイミングを連続的かつ広範囲に制御できるので、該吸気バルブの閉時期を例えば早める制御（早閉じ制御）をすれば、吸気を略大気圧状態で取り入れつつ、吸入空気量を制御することが可能となり、これによって、ポンピングロスの低減による燃費向上を図れる。
【０００４】
【発明が解決しようとする課題】
ところで、従来の吸気絞り弁でエンジンの吸入空気量を制御する構成では、吸気音以外の騒音（以下、暗騒音ともいう）が小さく、相対的に吸気音の車室内への影響が大きくなる条件（低車速，低回転，低負荷）は、吸気絞り弁が閉じられる条件でもあったため、吸気管内に発生する吸気脈動が吸気絞り弁で減衰され（図９（ｂ）参照）、吸気管からの放射音が比較的小さく、車室内の騒音が吸気音によって悪化することは少なかった。
【０００５】
しかし、前述のように、吸気を略大気圧状態で取り入れつつ、吸入空気量を吸気バルブのバルブタイミングで制御する構成では、吸気絞り弁が略全開であるため、吸気管内に発生する吸気脈動が吸気絞り弁で減衰されることがなく（図９（ａ）参照）、暗騒音が小さく相対的に吸気音の車室内への影響が大きくなる条件では、吸気管の空気取り入れ口等からの放射や、吸気管の車体取り付け部からの伝播等によって、車室内の騒音が悪化する要因になってしまうという問題があった。
【０００６】
本発明は上記問題点に鑑みなされたものであり、吸気を略大気圧状態で取り入れつつ、吸入空気量を吸気バルブのバルブタイミングで制御する構成のエンジンにおいて、運転性の悪化を回避しつつ、吸気音による車室内騒音の悪化を抑止できるようにすることを目的とする。
【０００７】
【課題を解決するための手段】

そのため、請求項１記載の発明は、吸気バルブのバルブタイミングを制御することでエンジンの吸入空気量を目標吸入空気量に制御する構成であって、吸気管の途中に吸気絞り弁を備えた車両用エンジンの吸気制御装置において、車両において吸気騒音の影響が大きくなる条件のときに、目標吸入空気量に応じた目標の吸気負圧を発生させるべく、前記吸気絞り弁を閉じ側に制御する構成とした。
【０００８】
かかる構成によると、吸気騒音の影響が大きくなる条件のときに、吸気絞り弁を閉じて吸気脈動の減衰を図るが、該吸気絞り弁の閉制御においては、目標吸入空気量に応じた目標の吸気負圧になるような開度にまで閉じ、吸気脈動の減衰を図る吸気絞り弁の閉じ制御状態で、一定の吸気負圧に制御される。
【０００９】
請求項２記載の発明では、車両において吸気騒音の影響が大きくなる条件を車速に基づいて判定する構成とした。
【００１０】
かかる構成によると、車速が高いときにはタイヤ騒音や車体の風切り音などが大きくなるが、係る吸気音以外の騒音（暗騒音）が小さい条件では、車室内において吸気騒音が目立ち、車両において吸気騒音の影響が大きくなるので、吸気絞り弁を閉じ側に制御し、吸気管内に発生する空気脈動を吸気絞り弁で減衰させるようにする。
【００１１】
請求項３記載の発明では、車両において吸気騒音の影響が大きくなる条件を、車速及びエンジン回転速度に基づいて判定する構成とした。
【００１２】
かかる構成によると、車速が高いときには、タイヤ騒音や車体の風切り音などが大きくなり、また、エンジン回転速度が高い場合には、機械音等が大きくなるから、吸気音以外の騒音としてタイヤ騒音，車体の風切り音，機械音等が小さくなる条件が判定され、係る吸気音以外の騒音（暗騒音）が小さく車室内において吸気騒音が目立つときに、吸気絞り弁を閉じ側に制御し、吸気管内に発生する空気脈動を吸気絞り弁で減衰させるようにする。
【００１３】
請求項４記載の発明では、車両において吸気騒音の影響が大きくなる条件を、車速及びエンジン回転速度及びエンジン負荷に基づいて判定する構成とした。
【００１４】
かかる構成によると、車速が高いときには、タイヤ騒音や車体の風切り音などが大きくなり、また、エンジン回転速度が高い場合には、機械音等が大きくなるから、吸気音以外の騒音としてタイヤ騒音，車体の風切り音，機械音等が小さくなる条件が判定されることになり、更に、エンジン負荷が高く、吸入空気量が多くなる条件を、吸気音が大きくなる条件として判定する。
【００１５】
請求項５記載の発明では、車両において吸気騒音の影響が大きくなる条件を、車速及びエンジン回転速度及び前記吸気バルブの閉時期に基づいて判定する構成とした。
【００１６】
かかる構成によると、車速が高いときには、タイヤ騒音や車体の風切り音などが大きくなり、また、エンジン回転速度が高い場合には、機械音等が大きくなるから、吸気音以外の騒音としてタイヤ騒音，車体の風切り音，機械音等が小さくなる条件が判定されることになり、更に、吸気バルブの閉時期は、吸気が遮断される時期であり、ピストンスピードが高く吸気の流速が高いときに、吸気バルブを閉じると、大きな吸気騒音が発生することになり、吸気バルブの閉時期が、ピストンスピードの高い時期であるか否かによって、吸気音が大きくなる条件が判定されることになる。
【００１７】
請求項６記載の発明では、前記吸気絞り弁の閉じ側への制御に伴う吸入空気量の変動を、前記吸気バルブのバルブタイミングにて補正する構成とした。
【００１８】
かかる構成によると、吸気絞り弁を閉じることによる吸入空気量の低下を、吸気バルブのバルブタイミングを吸入空気量が増大する方向に修正することで補う。
【００１９】
請求項７記載の発明では、請求項６記載の構成において、所定の高負荷域において、前記吸気絞り弁を閉じ側に制御することを禁止する構成とした。
【００２０】
かかる構成によると、要求空気量が多い高負荷側で、吸気脈動の減衰を図るべく吸気絞り弁を閉じると、吸気バルブのバルブタイミングで空気量の低下を補おうとしても、要求空気量が得られなくなる場合があるので、所定の高負荷域では吸気脈動の減衰による騒音低減よりも、要求空気量の確保を優先させるべく、たとえ車両において吸気騒音の影響が大きくなる条件であっても、吸気絞り弁を閉じ側に制御しない。
【００２１】
【発明の効果】
請求項１記載の発明によると、目標吸入空気量に応じた目標の吸気負圧になるように吸気絞り弁を閉じるので、吸気音の減衰のためにポンピングロスが大幅に増大することを抑止できると共に、吸気絞り弁の閉制御に伴う吸入空気量の低下を補正する制御を簡易かつ精度良く行わせることができるという効果がある。
【００２２】
請求項２記載の発明によると、タイヤ騒音，車体の風切り音が小さく相対的に吸気音が目立つことになる条件において、吸気騒音を低減させ、車室内騒音の悪化を防止できるという効果がある。
【００２３】
請求項３記載の発明によると、タイヤ騒音，車体の風切り音，機械音が小さく相対的に吸気音が目立つことになる条件において、吸気騒音を低減させ、車室内騒音の悪化を防止できるという効果がある。
【００２４】
請求項４記載の発明によると、タイヤ騒音，車体の風切り音，機械音等が小さく相対的に吸気音が目立つことになる条件、及び、吸入空気量が多く吸気音が大きくなる条件において、吸気絞り弁を閉じることで、車室内騒音の悪化を防止できるという効果がある。
【００２５】
請求項５記載の発明によると、タイヤ騒音，車体の風切り音，機械音等が小さく相対的に吸気音が目立つことになる条件、及び、吸気バルブの閉時期が、吸気音が大きくなるタイミングであるときに、吸気絞り弁を閉じることで、車室内騒音の悪化を防止できるという効果がある。
【００２６】
請求項６記載の発明によると、吸気脈動（吸気音）の減衰を図って吸気絞り弁を閉じても、エンジンの吸入空気量が低下することを抑止でき、運転性の悪化を防止できるという効果がある。
【００２７】
請求項７記載の発明によると、高負荷域において要求空気量が確保できなくなることを回避でき、動力性能の低下を回避できるという効果がある。
【００２８】
【発明の実施の形態】
以下に本発明の実施の形態を図に基づいて説明する。図１は、実施の形態におけるエンジンのシステム構成を示す図である。
【００２９】
この図１において、車両用の４サイクルガソリンエンジン１には、電磁動弁機構２により開閉時期が電子制御される吸気バルブ３及び排気バルブ４が各気筒に装着されている。
【００３０】
各気筒の吸気バルブ３上流側の吸気ポート５には、インジェクター６が装着され、燃焼室７には点火栓８が装着されている。また、前記点火栓８毎に点火コイル９が設けられている。
【００３１】
エンジン１の本体には、各気筒の基準ピストン位置で基準信号を出力すると共に、単位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、吸入空気流量を検出するエアフローメータ11、冷却水温度を検出する水温センサ12が装着される。この他、図示しない車両のアクセルペダルの開度ＡＰＯを検出するアクセル開度センサ13や車速センサ14等が配設されている。
【００３２】
前記各種センサ類の検出信号はコントロールユニット15に出力され、コントロールユニット15は、これらの検出信号に基づいて前記インジェクター６に噴射パルス信号を出力して燃料噴射量・燃料噴射時期の制御を行い、前記点火コイル９に点火信号を出力して点火時期の制御を行い、更に、前記電磁動弁機構２に弁駆動信号を出力して吸気バルブ３及び排気バルブ４のバルブタイミングを制御する。
【００３３】
また、吸気ポート５上流側には吸気絞り弁16が介装され、この吸気絞り弁16はアクチュエータとしてのモータ17によって開閉駆動されるようになっている。前記電磁動弁機構２の構成を図２に示す。
【００３４】
図２に示す電磁動弁機構２は、シリンダヘッド上に設けられる非磁性材料製のハウジング21と、吸気バルブ３（又は排気バルブ４、以下吸気バルブ３で代表する) のステム31に一体に設けられてハウジング21内に移動自由に収納されるアーマチュア22と、該アーマチュア22を吸引して吸気バルブ３を閉弁作動させる電磁力を発揮可能なようにアーマチュア22の上面に対向する位置でハウジング21内に固定配置される閉弁用電磁石23と、該アーマチュア22を吸引して吸気バルブ３を開弁作動させる電磁力を発揮可能なようにアーマチュア22の下面に対向する位置でハウジング21内に固定配置される開弁用電磁石24と、吸気バルブ３の閉弁方向に向けてアーマチュア22を付勢する閉弁側戻しバネ25と、吸気バルブ３の開弁方向に向けてアーマチュア22を付勢する開弁側戻しバネ26と、を備えて構成される。
【００３５】
そして、閉弁用電磁石23と開弁用電磁石24とを共に消磁したときに、吸気バルブ３は全開位置と閉弁位置との間の略中央位置にあるように、閉弁側戻しバネ25と開弁側戻しバネ26とのバネ力が設定され、閉弁用電磁石23のみを励磁したときに吸気バルブ３は閉弁し、開弁用電磁石24のみを励磁したときに吸気バルブ３は開弁するように駆動される。
【００３６】
前記電磁動弁機構２による吸気バルブ３及び排気バルブ４のバルブタイミングは、エンジン１の運転条件に基づいて設定された目標バルブタイミングとなるように制御されるが、特に、吸気バルブ３の閉時期ＩＶＣを、アクセル開度ＡＰＯとエンジン回転速度Ｎｅとに基づいて設定された目標吸入空気量に基づいて早閉じ方向に可変制御してシリンダ吸入空気量を各気筒毎に制御するようになっている。
【００３７】
尚、吸気バルブ３の開時期は排気上死点付近に固定される。前記吸気バルブ３の閉時期ＩＶＣによる吸入空気量制御においては、まず、アクセル開度ＡＰＯとエンジン回転速度Ｎｅとに応じて予め目標吸入空気量を記憶したマップ（図３参照）から、そのときのアクセル開度ＡＰＯ及びエンジン回転速度Ｎｅに対応する目標吸入空気量を検索し、次に、基準の吸気負圧状態（例えば大気圧状態）に対応して前記目標吸入空気量と吸気バルブ３の閉時期ＩＶＣとの相関を記憶したテーブル（図４参照）を検索し、そのときの目標吸入空気量に対応する閉時期ＩＶＣを目標値として求める。そして、前記閉時期ＩＶＣの目標値において吸気バルブ３を閉じるべく、前記電磁動弁機構２に弁駆動信号を出力する。
【００３８】
尚、吸気バルブ３の閉時期ＩＶＣにより吸入空気量を制御する領域では、吸気絞り弁16を略全開付近に制御するが、吸気バルブ３の閉時期ＩＶＣを最大限に早めても目標吸入空気量に制御できない領域が存在する場合に、当該領域においては、吸気バルブ３の閉時期ＩＶＣを最大限に早い時期に固定しておいて、吸気絞り弁16を閉じて目標の吸入空気量に制御する構成であっても良い。
【００３９】
次に、上記構成の吸気制御装置において、吸気音による車室内騒音の悪化を回避するための制御を、図５のフローチャートに従って説明する。図５のフローチャートにおいて、Ｓ１では、エンジン負荷（目標吸入空気量）が予め記憶された第１基準値（第１基準空気量）以上で、吸気音が所定値以上に大きくなる条件であるか否かを判別する。
【００４０】
ここで、目標吸入空気量に制御するために吸気絞り弁16を閉じる必要が生じる領域では、吸気絞り弁16を閉じることで吸気脈動が吸気絞り弁16の部分で減衰されることになるため、前記Ｓ１で判定される高負荷領域には、目標吸入空気量に制御するために吸気絞り弁16を閉じる必要が生じる領域は含まれない。
【００４１】
Ｓ１で、所定の高負荷域でないと判別されたときには、Ｓ５へ進んで、通常に吸気絞り弁16の開度を制御する。一方、Ｓ１で所定の高負荷域であると判別されたときには、Ｓ２へ進み、エンジン回転数が予め記憶された基準回転数以下であるか否かを判別することで、吸気音以外の騒音（暗騒音）の１つであるエンジンの機械音が所定値以下に小さくなる条件であるか否かを判別する。
【００４２】
エンジンの機械音が小さいと、相対的に吸気音が車室内の騒音に大きく影響することになるが、逆に、エンジンの機械音が高いと、吸気音の車室内騒音に対する影響が小さく、たとえ吸気絞り弁16を閉じ側に制御して、吸気脈動を減衰させるようにしても、車室内の騒音の低減に寄与することにならず、ポンピングロスを無用に増大させることになってしまう。
【００４３】
そこで、エンジン回転数が予め記憶された基準回転数を超えるときには、Ｓ１で吸気音が小さいと判定された場合と同様に、Ｓ５へ進んで、吸気絞り弁16を通常に制御する。
【００４４】
また、エンジン回転数が予め記憶された基準回転数以下であって、吸気音以外の騒音（暗騒音）の１つであるエンジンの機械音が小さく、吸気音が車室内の騒音に大きく影響する条件であると判断されたときには、Ｓ３へ進む。
【００４５】
Ｓ３では、車速が予め記憶された基準速度以下であるか否かを判別することで、吸気音以外の騒音（暗騒音）の１つであるタイヤ騒音等が所定値以下に小さくなる条件であるか否かを判別する。
【００４６】
車速が低くタイヤ騒音が小さいと、相対的に吸気音が車室内の騒音に大きく影響することになるが、逆に、車速が高くタイヤ騒音が高いと、吸気音の車室内騒音に対する影響が小さく、たとえ吸気絞り弁16を閉じ側に制御して、吸気脈動を減衰させるようにしても、車室内の騒音の低減に寄与することにならず、ポンピングロスを無用に増大させることになってしまう。
【００４７】
そこで、車速が予め記憶された基準速度を超えるときには、Ｓ１で吸気音が小さいと判定された場合と同様に、Ｓ５へ進んで、吸気絞り弁16を通常に制御する。
【００４８】
また、車速が予め記憶された基準速度以下であって、吸気音以外の騒音（暗騒音）の１つであるタイヤ騒音等が小さく、吸気音が車室内の騒音に大きく影響する条件であると判断されたときには、Ｓ４へ進む。
【００４９】
Ｓ４では、エンジン負荷（目標吸入空気量）が予め記憶された第２基準値（＞第１基準値）以下であるか否かを判別する。エンジン負荷が第２基準値を超える条件は、エンジン負荷が第１基準値以上である条件に含まれることになり、吸気音が高く、吸気絞り弁16を閉じ側に制御すれば、吸気脈動を減衰できることになる。
【００５０】
しかし、目標吸入空気量が高い条件下で、吸気脈動を減衰させるべく、吸気絞り弁16を閉じると、吸気バルブ３の閉時期ＩＶＣを最大限に遅くしても目標吸入空気量を得られなくなる場合がある。そこで、吸気絞り弁16を、吸気脈動を減衰させるために閉じても、吸気バルブ３の閉時期ＩＶＣを補正することで目標吸入空気量が得られる負荷範囲内でのみ、吸気絞り弁16を閉じ側に制御させるために、前記Ｓ４の判定処理が設けられている。
【００５１】
従って、前記Ｓ４では、吸気脈動を減衰させるために吸気絞り弁16を閉じた状態で、吸気バルブ３の閉時期ＩＶＣを最大限に遅くして得られる吸入空気量よりも、そのときの目標吸入空気量が大きいか否かを判別させるものである。
【００５２】
Ｓ４で、エンジン負荷（目標吸入空気量）が前記第２基準値を超えると判別されたときには、吸気絞り弁16を閉じると、目標吸入空気量に制御することができなくなるため、騒音の低減よりも要求空気量の確保を優先させ、Ｓ５へ進んで、吸気絞り弁16を通常に制御する。
【００５３】
一方、Ｓ４で、エンジン負荷（目標吸入空気量）が前記第２基準値未満であると判別されたときには、吸気音が大きく、かつ、暗騒音が小さく、かつ、吸気絞り弁16を閉じ側に制御しても目標吸入空気量を得られる条件であり、このときには、Ｓ６へ進んで、吸気絞り弁16を閉じ側に制御し、吸気管内に発生した空気脈動が前記吸気絞りによって減衰されるようにする。
【００５４】
ここで、前記吸気絞り弁16の閉じ制御においては、閉じ制御によって通常制御状態よりも大きな目標負圧（例えば−50〜−100mmHg）が得られるように吸気絞り弁16の開口面積を制御する。かかる構成とすれば、無用に吸気負圧が大きくなってポンピングロスが過剰に大きくなることを防止できると共に、後述する吸気バルブ３の閉時期の補正による吸入空気量の修正が容易に行える。
【００５５】
前記目標負圧は、目標吸入空気量に応じて異なる値に設定される。目標負圧を得るために要求される吸気絞り弁16の開口面積は、例えば、図６に示すような吸気負圧と開口面積／回転数との相関を示すテーブルから、目標負圧に対応する開口面積／回転数を求め、該開口面積／回転数とそのときのエンジン回転数とから求めることができ、前記開口面積に対応する開度を求めてモータ17を制御すれば良い。
【００５６】
Ｓ６で、吸気絞り弁16を閉じ側に制御すると、Ｓ７へ進み、吸気絞り弁16を閉じること（負圧の増大）による吸入空気量の低下を補正するために、吸気バルブ３の閉時期ＩＶＣを補正する。
【００５７】
吸気絞り弁16の閉じ側への制御においては、目標負圧になるように制御されるから、吸気バルブ３を閉じるタイミングにおけるシリンダ容積が、負圧の増大分に見合って増大されるようにすれば良い。具体的には、図７に示すようなシリンダ容積と閉時期ＩＶＣとの相関を示すテーブルを参照し、吸気絞り弁16を通常に制御しているときの目標吸入空気量に対応する閉時期ＩＶＣでのシリンダ容積を負圧の増大分に見合って増大補正し、該増大補正されたシリンダ容積に対応する閉時期ＩＶＣを、吸気絞り弁16の閉制御状態において目標吸入空気量を得るための閉時期ＩＶＣとする。
【００５８】
ところで、上記実施の形態では、エンジン負荷を目標吸入空気量から判断する構成としたが、吸気バルブ３の閉時期ＩＶＣからエンジン負荷を判断することができ、更に、閉時期ＩＶＣが、ピストンスピードが所定速度以上であるクランク角範囲内に位置するか否かに基づいて、吸気音が大きくなる条件であるか否かを判別させることができる。
【００５９】
即ち、吸気バルブ３の閉時期ＩＶＣは、吸気が遮断される時期であり、ピストンスピードが高く吸気の流速が高いときに、吸気バルブ３を閉じると、大きな吸気騒音が発生することになり、吸気バルブ３の閉時期ＩＶＣが、ピストンスピードの高い時期（ＡＴＤＣ45°前後の所定角度範囲内）であるか否かによって、吸気音が大きくなる条件を判定できるものである。
【００６０】
図８のフローチャートは、吸気バルブ３の閉時期ＩＶＣによって吸気音が大きくなる条件であるか否かを判定させる実施の形態を示すものであり、Ｓ11では、吸気バルブ３の閉時期ＩＶＣが、ピストンスピードが所定速度よりも高い時期として予め記憶された基準角度範囲内（ＡＴＤＣ45°前後の所定角度範囲内）であるか否かを判別することで、吸気音が大きくなる条件であるか否かを判別する。
【００６１】
吸気バルブ３の閉時期ＩＶＣが前記基準角度範囲内であれば、前記図５のフローチャートに示した第１の実施形態と同様に、Ｓ12以降へ進み、エンジン回転，車速から暗騒音が小さくなる条件であるか否かを判別し（Ｓ12，Ｓ13）、暗騒音が小さくなる条件であれば、吸気絞り弁16を閉じ側に制御しても閉時期ＩＶＣの補正によってそのときの目標吸入空気量が得られる条件であるか否かを判別する（Ｓ14）。そして、目標吸入空気量が得られる条件であれば、吸気絞り弁16を目標負圧となるように閉じ側に制御し（Ｓ16）、吸気絞り弁16を閉じ側に制御した分だけ吸気バルブ3の閉時期ＩＶＣを補正する（Ｓ17）。
【００６２】
尚、吸気絞り弁16を閉じ側に制御しても閉時期ＩＶＣの補正によってそのときの目標吸入空気量が得られる条件であるか否かを，吸気バルブ3の閉時期ＩＶＣに基づいて判別させることができる。更に、吸気バルブ３の閉時期ＩＶＣが、ピストンスピードが所定速度よりも高い時期であって、かつ、吸気絞り弁16を閉じ側に制御しても閉時期ＩＶＣの補正によってそのときの目標吸入空気量が得られる条件であることを、吸気バルブ３の閉時期ＩＶＣが所定角度範囲内であるか否かに基づいて判定させる構成とすることもできる。
【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図。
【図２】電磁動弁機構の詳細を示す断面図。
【図３】目標吸入空気量のマップを示す線図。
【図４】目標吸入空気量に対応する閉時期のテーブルを示す線図。
【図５】騒音低減のための絞り弁制御の第1実施形態を示すフローチャート。
【図６】吸気負圧と開口面積／回転との相関を示す線図。
【図７】シリンダ容積と閉時期との相関を示す線図。
【図８】騒音低減のための絞り弁制御の第２実施形態を示すフローチャート。
【図９】絞り弁による吸気脈動の減衰効果を示す状態図。
【符号の説明】
１…エンジン、２…電磁動弁機構、３…吸気バルブ、４…排気バルブ、６…インジェクタ、７…燃焼室、８…点火栓、10…クランク角センサ、11…エアフローメータ、12…水温センサ、13…アクセル開度センサ、15…コントロールユニット、16…吸気絞り弁、17…モータ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intake control device for a vehicle engine configured to control an intake air amount of an engine to a target intake air amount by controlling valve timing of an intake valve, and more particularly, to reduce noise in a vehicle interior by controlling intake noise. It is related to the technology.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known an electromagnetically driven valve having a valve closing electromagnetic coil and a valve opening electromagnetic coil and configured to open and close an intake valve and an exhaust valve by electromagnetic force generated by the electromagnetic coil (Japanese Patent Laid-Open No. 8- No. 200025).
[0003]
With the electromagnetically driven valve, the valve timing can be controlled continuously and over a wide range. For example, if the intake valve closing timing is controlled to be advanced (early closing control), intake air is taken in at substantially atmospheric pressure. Thus, it becomes possible to control the amount of intake air, thereby improving fuel efficiency by reducing pumping loss.
[0004]
[Problems to be solved by the invention]
By the way, in the configuration in which the intake air amount of the engine is controlled by the conventional intake throttle valve, the noise other than the intake sound (hereinafter also referred to as background noise) is small, and the influence of the intake sound on the vehicle interior is relatively large. (Low vehicle speed, low rotation, low load) was also a condition that the intake throttle valve was closed, so that the intake pulsation generated in the intake pipe was attenuated by the intake throttle valve (see FIG. 9B), The radiated sound was relatively small, and the noise in the passenger compartment was rarely deteriorated by the intake sound.
[0005]
However, as described above, in the configuration in which the intake air amount is controlled at the valve timing of the intake valve while taking in the intake air at a substantially atmospheric pressure state, the intake air pulsation generated in the intake pipe is not generated because the intake throttle valve is substantially fully open. Under the condition that the noise is not attenuated by the intake throttle valve (see FIG. 9A) and the background noise is small and the influence of the intake sound on the vehicle interior is relatively large, radiation from the air intake of the intake pipe or the like In addition, there is a problem that the noise in the passenger compartment becomes worse due to propagation from the vehicle body mounting portion of the intake pipe.
[0006]
The present invention has been made in view of the above problems, and in an engine configured to control intake air amount at the valve timing of an intake valve while taking in intake air at a substantially atmospheric pressure state, while avoiding deterioration in drivability , The purpose of the present invention is to make it possible to suppress deterioration of vehicle interior noise due to intake noise.
[0007]
[Means for Solving the Problems]

Therefore, the invention according to claim 1 is a configuration in which the intake air amount of the engine is controlled to the target intake air amount by controlling the valve timing of the intake valve, and the vehicle includes an intake throttle valve in the middle of the intake pipe. In the engine intake control apparatus, the intake throttle valve is controlled to be closed in order to generate a target intake negative pressure corresponding to the target intake air amount when the influence of the intake noise is large in the vehicle It was.
[0008]
According to such a configuration, the intake throttle valve is closed to attenuate the intake pulsation under conditions where the influence of the intake noise becomes large. In the intake throttle valve closing control, a target value corresponding to the target intake air amount is set. The intake throttle valve is controlled to a constant negative intake pressure in a closed control state in which the intake throttle valve is closed so that the intake negative pressure is reached and the intake pulsation is attenuated.
[0009]
The invention according to claim 2 is configured to determine the condition that the influence of the intake noise becomes large in the vehicle based on the vehicle speed.
[0010]
According to such a configuration, tire noise and wind noise of the vehicle body increase when the vehicle speed is high, but under conditions where the noise (background noise) other than the intake noise is small, the intake noise is conspicuous in the passenger compartment and the intake noise of the vehicle is reduced. Since the influence becomes large, the intake throttle valve is controlled to the closed side so that the air pulsation generated in the intake pipe is attenuated by the intake throttle valve.
[0011]
In the invention according to claim 3, the condition that the influence of the intake noise becomes large in the vehicle is determined based on the vehicle speed and the engine rotation speed.
[0012]
According to such a configuration, when the vehicle speed is high, the tire noise and the wind noise of the vehicle body increase, and when the engine speed is high, the mechanical noise increases. When conditions for reducing wind noise, mechanical noise, etc. of the vehicle body are judged and the noise (background noise) other than the intake noise is small and intake noise is conspicuous in the passenger compartment, the intake throttle valve is controlled to the closed side, and the intake pipe The air pulsation generated in the engine is attenuated by the intake throttle valve.
[0013]
According to the fourth aspect of the present invention, the condition that the influence of the intake noise becomes large in the vehicle is determined based on the vehicle speed, the engine rotation speed, and the engine load.
[0014]
According to such a configuration, when the vehicle speed is high, the tire noise and the wind noise of the vehicle body increase, and when the engine speed is high, the mechanical noise increases. Conditions for reducing wind noise, mechanical noise, etc. of the vehicle body are determined, and conditions for increasing the engine load and increasing the intake air amount are determined as conditions for increasing the intake noise.
[0015]
In the fifth aspect of the present invention, the condition in which the influence of the intake noise becomes large in the vehicle is determined based on the vehicle speed, the engine rotation speed, and the closing timing of the intake valve.
[0016]
According to such a configuration, when the vehicle speed is high, the tire noise and the wind noise of the vehicle body increase, and when the engine speed is high, the mechanical noise increases. The conditions for reducing the wind noise and mechanical noise of the vehicle body will be determined, and the closing timing of the intake valve is the timing when intake is shut off, and when the piston speed is high and the intake flow velocity is high, When the intake valve is closed, a large intake noise is generated, and the condition for increasing the intake sound is determined depending on whether the intake valve is closed at a high piston speed .
[0017]
According to the sixth aspect of the present invention, the intake air amount fluctuation due to the control of the intake throttle valve toward the closing side is corrected at the valve timing of the intake valve.
[0018]
According to such a configuration, the reduction in the intake air amount caused by closing the intake throttle valve is compensated by correcting the valve timing of the intake valve so that the intake air amount increases.
[0019]
According to a seventh aspect of the present invention, in the configuration according to the sixth aspect , the intake throttle valve is prohibited from being controlled to be closed in a predetermined high load region.
[0020]
According to such a configuration, when the intake throttle valve is closed to attenuate the intake pulsation on the high load side where the required air amount is large, the required air amount can be obtained even if the decrease in the air amount is compensated for at the valve timing of the intake valve. In order to give priority to securing the required air volume over the noise reduction due to the attenuation of intake pulsation in a predetermined high load range, even if the condition of the influence of intake noise in the vehicle is large, Do not control the throttle valve to the closed side.
[0021]
【The invention's effect】
According to the first aspect of the present invention, since the intake throttle valve is closed so as to achieve the target intake negative pressure corresponding to the target intake air amount, it is possible to suppress a significant increase in pumping loss due to the attenuation of the intake sound. In addition, there is an effect that the control for correcting the decrease in the intake air amount accompanying the closing control of the intake throttle valve can be performed easily and accurately.
[0022]
According to the second aspect of the invention, there is an effect that the intake noise can be reduced and the deterioration of the vehicle interior noise can be prevented under the condition that the tire noise and the wind noise of the vehicle body are small and the intake sound is relatively conspicuous.
[0023]
According to the third aspect of the invention, the effect of reducing the intake noise and preventing the deterioration of the vehicle interior noise under the condition that the tire noise, the wind noise of the vehicle body, and the mechanical noise are small and the intake noise is relatively conspicuous. There is.
[0024]
According to the fourth aspect of the present invention, in the condition that the tire noise, the wind noise of the vehicle body, the mechanical noise, etc. are small and the intake sound is relatively conspicuous, and in the condition that the intake air volume is large and the intake sound is large, By closing the throttle valve, there is an effect that deterioration of vehicle interior noise can be prevented.
[0025]
According to the fifth aspect of the invention, the tire noise, the wind noise of the vehicle body, the mechanical noise, etc. are small and the intake sound is relatively conspicuous, and the closing timing of the intake valve is the timing at which the intake sound increases. In some cases, closing the intake throttle valve has the effect of preventing deterioration of vehicle interior noise .
[0026]
According to the sixth aspect of the present invention, even if the intake pulsation (intake sound) is attenuated and the intake throttle valve is closed, it is possible to prevent the intake air amount of the engine from decreasing and to prevent the deterioration of drivability. There is.
[0027]
According to the seventh aspect of the invention, there is an effect that it is possible to avoid that the required air amount cannot be secured in a high load region, and it is possible to avoid a decrease in power performance.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a system configuration of an engine in the embodiment.
[0029]
In FIG. 1, a four-cycle gasoline engine 1 for a vehicle is equipped with an intake valve 3 and an exhaust valve 4 whose opening / closing timing is electronically controlled by an electromagnetic valve mechanism 2 in each cylinder.
[0030]
An injector 6 is attached to the intake port 5 upstream of the intake valve 3 of each cylinder, and an ignition plug 8 is attached to the combustion chamber 7. An ignition coil 9 is provided for each ignition plug 8.
[0031]
The main body of the engine 1 outputs a reference signal at the reference piston position of each cylinder and outputs a unit angle signal for each unit crank angle, an air flow meter 11 for detecting an intake air flow rate, and a cooling water temperature. A water temperature sensor 12 for detecting the In addition, an accelerator opening sensor 13 and a vehicle speed sensor 14 for detecting an accelerator pedal opening APO of a vehicle (not shown) are provided.
[0032]
Detection signals from the various sensors are output to the control unit 15, and the control unit 15 outputs an injection pulse signal to the injector 6 based on these detection signals to control the fuel injection amount and fuel injection timing. An ignition signal is output to the ignition coil 9 to control the ignition timing, and a valve drive signal is output to the electromagnetic valve mechanism 2 to control the valve timing of the intake valve 3 and the exhaust valve 4.
[0033]
An intake throttle valve 16 is interposed upstream of the intake port 5, and the intake throttle valve 16 is driven to open and close by a motor 17 as an actuator. The configuration of the electromagnetic valve mechanism 2 is shown in FIG.
[0034]
The electromagnetic valve mechanism 2 shown in FIG. 2 is provided integrally with a housing 21 made of a non-magnetic material provided on a cylinder head and a stem 31 of an intake valve 3 (or an exhaust valve 4, hereinafter referred to as an intake valve 3). The armature 22 that is freely stored in the housing 21 and the housing 21 at a position facing the upper surface of the armature 22 so as to exert an electromagnetic force for sucking the armature 22 and closing the intake valve 3. A valve-closing electromagnet 23 fixedly disposed inside and fixed in the housing 21 at a position facing the lower surface of the armature 22 so as to exert an electromagnetic force for attracting the armature 22 and opening the intake valve 3 The valve opening electromagnet 24, the valve closing side return spring 25 that urges the armature 22 toward the valve closing direction of the intake valve 3, and the armature 22 that urges the armature 22 toward the valve opening direction of the intake valve 3. Configured to include that the valve-opening return spring 26.
[0035]
Then, when both the valve closing electromagnet 23 and the valve opening electromagnet 24 are demagnetized, the valve closing side return spring 25 and the valve closing side return spring 25 are arranged so that the intake valve 3 is at a substantially central position between the fully opened position and the valve closing position. When the spring force with the valve-opening return spring 26 is set and only the valve closing electromagnet 23 is excited, the intake valve 3 is closed, and when only the valve opening electromagnet 24 is excited, the intake valve 3 is opened. To be driven.
[0036]
The valve timing of the intake valve 3 and the exhaust valve 4 by the electromagnetic valve mechanism 2 is controlled to be a target valve timing set based on the operating conditions of the engine 1, and in particular, the closing timing of the intake valve 3. The cylinder intake air amount is controlled for each cylinder by variably controlling IVC in the early closing direction based on the target intake air amount set based on the accelerator opening APO and the engine rotational speed Ne. .
[0037]
The opening timing of the intake valve 3 is fixed near the exhaust top dead center. In the intake air amount control based on the closing timing IVC of the intake valve 3, first, from a map (see FIG. 3) in which the target intake air amount is stored in advance according to the accelerator opening APO and the engine rotational speed Ne. A target intake air amount corresponding to the accelerator opening APO and the engine rotational speed Ne is searched, and then the target intake air amount and the intake valve 3 are closed corresponding to a reference intake negative pressure state (for example, an atmospheric pressure state). A table (see FIG. 4) storing the correlation with the timing IVC is searched, and the closing timing IVC corresponding to the target intake air amount at that time is obtained as a target value. Then, a valve drive signal is output to the electromagnetic valve mechanism 2 in order to close the intake valve 3 at the target value of the closing timing IVC.
[0038]
In the region where the intake air amount is controlled by the closing timing IVC of the intake valve 3, the intake throttle valve 16 is controlled to be substantially fully open. However, even if the closing timing IVC of the intake valve 3 is advanced to the maximum, the target intake air amount is controlled. When there is a region that cannot be controlled, the closing timing IVC of the intake valve 3 is fixed at the earliest possible time in this region, and the intake throttle valve 16 is closed to control the target intake air amount. It may be a configuration.
[0039]
Next, in the intake control device having the above-described configuration, control for avoiding deterioration of vehicle interior noise due to intake noise will be described with reference to the flowchart of FIG. In the flowchart of FIG. 5, in S1, whether or not the engine load (target intake air amount) is equal to or greater than a first reference value (first reference air amount) stored in advance and the intake sound is greater than a predetermined value. Is determined.
[0040]
Here, in the region where it is necessary to close the intake throttle valve 16 to control the target intake air amount, the intake pulsation is attenuated at the intake throttle valve 16 by closing the intake throttle valve 16, The high load region determined in S1 does not include a region where the intake throttle valve 16 needs to be closed in order to control the target intake air amount.
[0041]
If it is determined in S1 that the predetermined high load range is not satisfied, the process proceeds to S5, and the opening degree of the intake throttle valve 16 is normally controlled. On the other hand, when it is determined in S1 that the predetermined high load range is reached, the process proceeds to S2, and it is determined whether or not the engine speed is equal to or lower than a pre-stored reference speed, thereby making it possible to detect noises other than the intake sound ( It is determined whether or not the engine noise, which is one of (background noise), is a condition where the engine noise is reduced to a predetermined value or less.
[0042]
If the mechanical noise of the engine is low, the intake noise will have a large effect on the noise in the vehicle interior. Conversely, if the mechanical noise of the engine is high, the influence of the intake noise on the vehicle interior noise will be small. Even if the intake throttle valve 16 is controlled to the closed side to attenuate the intake pulsation, it does not contribute to the reduction of the noise in the passenger compartment, and the pumping loss is unnecessarily increased.
[0043]
Therefore, when the engine speed exceeds the pre-stored reference speed, the process proceeds to S5, and the intake throttle valve 16 is controlled normally, as in the case where it is determined in S1 that the intake noise is low.
[0044]
Further, the engine speed is equal to or lower than a pre-stored reference speed, and the engine noise, which is one of the noises (background noise) other than the intake noise, is small, and the intake noise greatly affects the noise in the passenger compartment. When it is determined that the condition is satisfied, the process proceeds to S3.
[0045]
In S3, it is a condition that the tire noise or the like, which is one of noises (background noise) other than the intake sound, is reduced to a predetermined value or less by determining whether or not the vehicle speed is equal to or lower than a reference speed stored in advance. It is determined whether or not.
[0046]
If the vehicle speed is low and the tire noise is low, the intake noise will have a large effect on the noise in the vehicle interior. Conversely, if the vehicle speed is high and the tire noise is high, the influence of the intake noise on the vehicle interior noise is small. Even if the intake throttle valve 16 is controlled to be closed and the intake pulsation is attenuated, it does not contribute to the reduction of noise in the passenger compartment, and the pumping loss is unnecessarily increased. .
[0047]
Therefore, when the vehicle speed exceeds the prestored reference speed, the process proceeds to S5, and the intake throttle valve 16 is controlled normally, as in the case where it is determined in S1 that the intake noise is low.
[0048]
Further, the vehicle speed is equal to or lower than a pre-stored reference speed, tire noise, which is one of noises (background noise) other than the intake sound, is small, and the intake sound greatly affects the noise in the vehicle interior. When it is determined, the process proceeds to S4.
[0049]
In S4, it is determined whether or not the engine load (target intake air amount) is equal to or less than a second reference value (> first reference value) stored in advance. The condition that the engine load exceeds the second reference value is included in the condition that the engine load is equal to or higher than the first reference value. If the intake noise is high and the intake throttle valve 16 is controlled to the closed side, the intake pulsation is reduced. It can be attenuated.
[0050]
However, if the intake throttle valve 16 is closed to attenuate the intake pulsation under a condition where the target intake air amount is high, the target intake air amount cannot be obtained even if the closing timing IVC of the intake valve 3 is delayed as much as possible. There is a case. Therefore, even if the intake throttle valve 16 is closed to attenuate intake pulsation, the intake throttle valve 16 is closed only within a load range in which the target intake air amount can be obtained by correcting the closing timing IVC of the intake valve 3. In order to make it control to the side, the determination process of said S4 is provided.
[0051]
Therefore, in S4, the target intake at that time is larger than the intake air amount obtained by maximally delaying the closing timing IVC of the intake valve 3 with the intake throttle valve 16 closed in order to attenuate the intake pulsation. It is determined whether or not the air amount is large.
[0052]
When it is determined in S4 that the engine load (target intake air amount) exceeds the second reference value, it becomes impossible to control the target intake air amount when the intake throttle valve 16 is closed. Also, priority is given to securing the required air amount, and the process proceeds to S5 to control the intake throttle valve 16 normally.
[0053]
On the other hand, when it is determined in S4 that the engine load (target intake air amount) is less than the second reference value, the intake noise is large, the background noise is small, and the intake throttle valve 16 is closed. The condition is that the target intake air amount can be obtained even if the control is performed. In this case, the routine proceeds to S6, where the intake throttle valve 16 is controlled to the closed side so that the air pulsation generated in the intake pipe is attenuated by the intake throttle. To.
[0054]
Here, in the closing control of the intake throttle valve 16, the opening area of the intake throttle valve 16 is controlled so that a larger target negative pressure (for example, −50 to −100 mmHg) than in the normal control state can be obtained by the closing control. With this configuration, it is possible to prevent the intake negative pressure from becoming unnecessarily large and the pumping loss from becoming excessively large, and to easily correct the intake air amount by correcting the closing timing of the intake valve 3 described later.
[0055]
The target negative pressure is set to a different value according to the target intake air amount . The opening area of the intake throttle valve 16 required to obtain the target negative pressure corresponds to the target negative pressure from, for example, a table showing the correlation between the intake negative pressure and the opening area / rotation speed as shown in FIG. The opening area / number of revolutions can be obtained and can be obtained from the opening area / number of revolutions and the engine speed at that time . The motor 17 can be controlled by obtaining the opening corresponding to the opening area .
[0056]
When the intake throttle valve 16 is controlled to be closed in S6, the process proceeds to S7, and the intake valve 3 closing timing IVC is corrected in order to correct the decrease in the intake air amount caused by closing the intake throttle valve 16 (increasing negative pressure). Correct.
[0057]
In controlling the intake throttle valve 16 to the closing side, control is performed so that the target negative pressure is reached. Therefore, the cylinder volume at the timing of closing the intake valve 3 is increased in accordance with the increase in the negative pressure. It ’s fine. Specifically, referring to a table showing the correlation between the cylinder volume and the closing timing IVC as shown in FIG. 7, the closing timing IVC corresponding to the target intake air amount when the intake throttle valve 16 is normally controlled. The cylinder volume at the cylinder is increased and corrected in accordance with the increase in the negative pressure, and the closing timing IVC corresponding to the increased cylinder volume is closed to obtain the target intake air amount in the closed control state of the intake throttle valve 16. Time IVC.
[0058]
In the above embodiment, the engine load is determined from the target intake air amount. However, the engine load can be determined from the closing timing IVC of the intake valve 3, and the closing timing IVC is determined by the piston speed. Based on whether or not the position is within a crank angle range that is equal to or higher than a predetermined speed, it is possible to determine whether or not the condition is that the intake sound is increased.
[0059]
That is, when the intake valve 3 is closed when the intake valve 3 is closed when the piston speed is high and the flow velocity of the intake air is high, the closing timing IVC of the intake valve 3 is shut off. The condition for increasing the intake noise can be determined based on whether or not the closing timing IVC of the valve 3 is a time when the piston speed is high (within a predetermined angle range of around ATDC 45 °).
[0060]
The flowchart of FIG. 8 shows an embodiment in which it is determined whether or not it is a condition that the intake sound becomes louder due to the closing timing IVC of the intake valve 3. In S11, the closing timing IVC of the intake valve 3 is changed to the piston. It is determined whether or not it is a condition for increasing the intake sound by determining whether or not it is within a pre-stored reference angle range (within a predetermined angle range around 45 ° ATDC) as a time when the speed is higher than the predetermined speed. Determine.
[0061]
If the closing timing IVC of the intake valve 3 is within the reference angle range, as in the first embodiment shown in the flowchart of FIG. (S12, S13), and if the background noise is reduced, even if the intake throttle valve 16 is controlled to the closed side, the target intake air amount at that time is obtained by correcting the closing timing IVC. It is determined whether or not the conditions are obtained (S14). If the target intake air amount is obtained, the intake throttle valve 16 is controlled to the closed side so as to reach the target negative pressure (S16), and the intake valve 3 is controlled by the amount that the intake throttle valve 16 is controlled to the closed side. The closing timing IVC is corrected (S17).
[0062]
Whether the target intake air amount at that time can be obtained by correcting the closing timing IVC even if the intake throttle valve 16 is controlled to close is determined based on the closing timing IVC of the intake valve 3. be able to. Furthermore, even if the closing timing IVC of the intake valve 3 is a timing when the piston speed is higher than a predetermined speed and the intake throttle valve 16 is controlled to the closing side, the target intake air at that time is corrected by correcting the closing timing IVC. It may be configured to determine that the amount is obtained based on whether or not the closing timing IVC of the intake valve 3 is within a predetermined angle range.
[Brief description of the drawings]
FIG. 1 is a system diagram of an engine in an embodiment.
FIG. 2 is a sectional view showing details of an electromagnetic valve mechanism.
FIG. 3 is a diagram showing a map of a target intake air amount.
FIG. 4 is a diagram showing a closing timing table corresponding to a target intake air amount;
FIG. 5 is a flowchart showing a first embodiment of throttle valve control for noise reduction.
FIG. 6 is a diagram showing the correlation between intake negative pressure and opening area / rotation.
FIG. 7 is a diagram showing the correlation between cylinder volume and closing timing.
FIG. 8 is a flowchart showing a second embodiment of throttle valve control for noise reduction.
FIG. 9 is a state diagram showing an attenuation effect of intake pulsation by a throttle valve.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Electromagnetic valve mechanism, 3 ... Intake valve, 4 ... Exhaust valve, 6 ... Injector, 7 ... Combustion chamber, 8 ... Spark plug, 10 ... Crank angle sensor, 11 ... Air flow meter, 12 ... Water temperature sensor , 13 ... Accelerator opening sensor, 15 ... Control unit, 16 ... Intake throttle valve, 17 ... Motor

Claims

In a configuration for controlling the intake air amount of the engine to a target intake air amount by controlling the valve timing of the intake valve, the intake control device for a vehicle engine provided with an intake throttle valve in the middle of the intake pipe,
In a vehicle engine characterized by controlling the intake throttle valve to a closed side so as to generate a target intake negative pressure corresponding to a target intake air amount when the influence of intake noise is large in the vehicle Intake control device.

2. The intake control apparatus for a vehicle engine according to claim 1, wherein a condition under which the influence of intake noise in the vehicle becomes large is determined based on the vehicle speed .

2. The intake control apparatus for a vehicle engine according to claim 1, wherein a condition under which the influence of the intake noise is increased in the vehicle is determined based on the vehicle speed and the engine rotation speed.

2. The intake control apparatus for a vehicle engine according to claim 1, wherein a condition under which the influence of intake noise in the vehicle becomes large is determined based on a vehicle speed, an engine rotation speed, and an engine load.

2. The intake control apparatus for a vehicle engine according to claim 1, wherein a condition under which the influence of intake noise increases in the vehicle is determined based on a vehicle speed, an engine speed, and a closing timing of the intake valve.

Vehicle engine according to any one of claims 1-5, characterized in that the variation of the intake air amount due to control of the closing side of the intake throttle valve, is corrected by the valve timing of the intake valve Intake control device.

7. The intake control apparatus for a vehicle engine according to claim 6 , wherein control of the intake throttle valve to the closed side is prohibited in a predetermined high load range.