JP2004332558A - Exhaust emission control device for internal combustion engine - Google Patents

Exhaust emission control device for internal combustion engine Download PDF

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JP2004332558A
JP2004332558A JP2003125669A JP2003125669A JP2004332558A JP 2004332558 A JP2004332558 A JP 2004332558A JP 2003125669 A JP2003125669 A JP 2003125669A JP 2003125669 A JP2003125669 A JP 2003125669A JP 2004332558 A JP2004332558 A JP 2004332558A
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valve
exhaust
internal combustion
combustion engine
intake
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JP3982449B2 (en
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Kojiro Okada
公二郎 岡田
Takashi Dougahara
隆 堂ヶ原
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Mitsubishi Motors Corp
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Mitsubishi Motors Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

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  • Valve Device For Special Equipments (AREA)
  • Exhaust-Gas Circulating Devices (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine for promoting the stabilization of combustion while accurately suppressing the exhaustion of unburnt gas at starting the internal combustion engine in the cold condition. <P>SOLUTION: The exhaust emission control device comprises a secondary air supply device 25 for jetting secondary air toward the opening of an exhaust port 7 to be opened/closed by an exhaust valve 3 of the internal combustion engine, valve control means 33, 34 for variably controlling a valve opening/closing timing for at least one of a suction valve 4 and an exhaust valve 5 or a valve lifting amount, a water temperature sensor 45 (an operation information detecting means) for detecting operation information for the internal combustion engine, and a controller (a control means) 9 for driving the secondary air supply device 24 and operating the valve control means when determining that the internal combustion engine is at a cold condition determined temperature Tc1 or lower, to increase an overlap amount B1 between the suction valve and the exhaust valve larger than that in steady state operation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、内燃機関の排気ガス中の未燃ガスの排出量を抑制できる内燃機関の排気浄化装置、特に、二次エアを排気ポート側より燃焼室に投入し、未燃ガスを再燃焼させる内燃機関の排気浄化装置に関する。
【０００２】
【従来の技術】
内燃機関はその燃焼行程で残留した未燃ガス（ＨＣ）が排気行程で排気ガスと共に排出される傾向にある。例えば図１７に示すように、シリンダヘッド１００とシリンダブロック１１０の燃焼室側隙間（クレビス）ｐ１やピストンとシリンダ壁間の燃焼室側隙間（クレビス）ｐ２に未燃ガス（ＨＣ）が侵入すると、これらには火炎が届かず燃え残る。しかも、ピストン頂部周縁ｐ３には経時的に燃えかすであるデポジットが堆積し、このデポジット生成物内の隙間にも未燃ガス（ＨＣ）が侵入すると、これには火炎が届かず燃え残る。更に、シリンダ壁ｐ４のオイル膜に未燃ガスが付着するとこれが燃え残る。又、シリンダヘッド１００の燃焼室壁１０１は温度が低いために火炎は燃焼室壁１０１の近くでは消炎し、シリンダヘッドの燃焼室壁近傍の未燃ガス（ＨＣ）も燃え残る傾向にある。
【０００３】
このように、燃焼行程で火炎非到達域に侵入している未燃ガス（ＨＣ）は燃焼室内が低圧化する排気行程において、火炎非到達域より排気ポートを経て排気され、排気ガス悪化を招く。特に、内燃機関はその冷態始動時おいて、その燃焼安定性を確保するため、比較的リッチな混合気が供給されており、燃焼行程で燃え残る未燃ガス（ＨＣ）の排出量が増加し易くなっている。
【０００４】
そこで、この対策として、不図示の排気路上に早期活性化する前段触媒と、その後方に主触媒を配備して冷態始動直後の未燃ガス（ＨＣ）の排出を抑制することが行なわれているが、この触媒だけでは触媒温度が低く活性が不充分な冷態始動時においては十分な未燃ガス（ＨＣ）の排出防止策と成っていない。
【０００５】
そこで、排気行程において、図１６に示すように、排気ポート１３０内に装着したノズル１４０により二次エアを排気弁１５０の背側より燃焼室１６０に向けて投入し、燃焼室１６０から排出されようとしている排気ガスを燃焼室に逆流させ、攪拌し、これにより、燃焼室１６０から排出される前に残留する未燃ガス（ＨＣ）を二次エアにより再燃焼させ、特に、排気行程での低圧化に応じて火炎非到達域より火炎到達域に達し、燃焼室から排出されようとしている未燃ガス（ＨＣ）を二次エアにより再燃焼させ、未燃ガスの排出を抑制している。
【０００６】
例えば、特開平８−１５８８５８号公報（特許文献１）には、冷態始動後に未燃ガス（ＨＣ）の低減を図るため、二次エアを吹き、しかも、排気流動バルブ（シャッター）を閉じるが、これによる内部ＥＧＲ量の上昇が燃焼不安定化を招くことより、排気バルブタイミングを進角して吸気バルブとのオーバーラップ量を小さくし、内部ＥＧＲ量の過度な上昇を防止し、燃焼安定化を図っている。
【０００７】
更に、特開２００１−２６３０５０号公報（特許文献２）には、冷態始動後に排気バルブを進角し、吸気バルブと排気バルブのオーバーラップ量を増加させ、排気管内への未燃ガスの流出を促進させ、これに二次エアを吹くことで未燃ガス（ＨＣ）の排気管内での後燃えを促進し、触媒の早期活性化を図り、未燃ガス排出を抑えるというものが開示される。
【０００８】
【特許文献１】
特開平８−１５８８５８号公報
【特許文献２】
特開２００１−２６３０５０号公報
【０００９】
【発明が解決しようとする課題】
このように、特許文献１の技術は二次エアを吹くことによる内部ＥＧＲ量の過度の上昇による燃焼不安定化を防止するために、排気バルブタイミングを進角して、燃焼安定化を図るというものであり、特許文献２の技術は排気管内での未燃ガス（ＨＣ）の燃焼促進により触媒の早期活性化を図り、未燃ガス（ＨＣ）排出を抑えるというものであります。
【００１０】
このように両特許文献の技術とも、二次エアと未燃ガス（ＨＣ）の反応による排気昇温効果（触媒早期活性化）を期待し、しかも、二次エア投入運転域において、空燃比リッチ化の度合いと二次エア投入量との最適化が難しく、未燃ガス（ＨＣ）の排出量が増加する場合がある、との点を改善することを考慮した技術と成っています。
【００１１】
しかし、両特許文献の技術は、燃焼室内への二次エア供給を積極的に的確に行なうことができるものではない。即ち、燃焼室内への二次エア流入および排気ガスの逆流をより促進し、これにより燃焼室内の未燃ガス（ＨＣ）を積極的に攪拌して再燃焼させ、その再燃焼反応による排気昇温効果（触媒早期活性化）及び未燃ガス（ＨＣ）低減効果、早期の燃焼安定化を促進するということはできない。
【００１２】
このため、燃焼室内へ積極的に二次エアおよび排気ガスを流入させ、燃焼室内の未燃ガス（ＨＣ）を積極的に攪拌して再燃焼し、未燃ガス（ＨＣ）の排出量を抑え、しかも、燃焼安定化を図ることが可能な装置が期待されている。
本発明は、以上のような課題に基づき、内燃機関の冷態始動時の未燃ガス（ＨＣ）の燃焼室内での再燃焼をより促進し、未燃ガス（ＨＣ）の排出量をより的確に抑え、燃焼安定化を促進することのできる内燃機関の排気浄化装置を提供することを目的とする。
【００１３】
【課題を解決するための手段】
請求項１の発明は、内燃機関の排気バルブにより開閉される排気ポートの開口に向けて２次エアを噴射する２次エア供給装置と、吸気バルブ又は排気バルブの少なくとも一方の開弁時期、開弁期間或いは弁リフト量を可変調整するバルブ調整手段と、内燃機関の運転情報を検出する運転情報検出手段と、内燃機関の運転情報より内燃機関が冷態判定温度を下回ると判定すると、前記２次エア供給装置を駆動すると共に前記バルブ調整手段を作動して、吸気バルブと排気バルブのオーバーラップ量を定常運転時より増大させる制御手段と、を備えたことを特徴とする。
【００１４】
このように、内燃機関の冷態始動時に、二次エア供給装置が二次エアを排気ポートの開口より燃焼室内に投入させ、バルブ調整手段が吸気バルブ又は排気バルブの少なくとも一方の開弁時期、開弁期間或いは弁リフト量を可変調整してオーバーラップ量を定常運転時より増大させ、これにより吸気バルブが開いた後の吸気負圧による排気引き戻し効果とオーバラップ中の二次エアの燃焼室への投入との相乗効果を利用して、二次エアおよび排気ガスをより多く燃焼室内に流入させ、燃焼室の未燃ガスを二次エアおよび逆流排気ガスと攪拌して再燃焼を促進させ、排気ガス昇温による燃焼安定化を早期に図り、排気ガス中に残留する未燃ガスを低減させることができる。更に、オーバーラップ量を増大させることによって、吸気ポートまで逆流排気ガスが到達し、吸気ポート壁面が加熱されて壁面付着燃料の霧化を促進することができる。
【００１５】
請求項２の発明は、請求項１記載の内燃機関の排気浄化装置において、前記バルブ調整手段が、吸気バルブの開弁期間あるいは弁リフト量を可変調整する吸気バルブ可変調整手段、及び、排気バルブの開弁期間あるいは弁リフト量を可変調整する排気バルブ可変調整手段の少なくとも一方を有することを特徴とする。
【００１６】
このように、吸気バルブ可変調整手段と排気バルブ可変調整手段の少なくとも一方が吸気バルブと排気バルブの少なくとも一方の開弁期間或いは弁リフト量を可変調整してオーバーラップ量を定常運転時より増大させ、これによって、吸気バルブが開いた後の吸気負圧による排気引き戻し効果とオーバラップ中の二次エアの燃焼室への投入との相乗効果を利用して、二次エアおよび排気ガスをより多く燃焼室内に流入させ、燃焼室の未燃ガスを二次エアおよび逆流排気ガスと攪拌して再燃焼を促進させ、排気ガス昇温による燃焼安定化を早期に図れ、排気ガス中に残留する未燃ガスを低減させることができる。更に、オーバーラップ量を増大させることによって、吸気ポートまで逆流排気ガスが到達し、吸気ポート壁面が加熱されて壁面付着燃料の霧化を促進することができる。
【００１７】
請求項３の発明は、請求項１記載の内燃機関の排気浄化装置において、前記バルブ調整手段が、吸気バルブの開弁時期、開弁期間あるいは弁リフト量を可変調整する吸気バルブ可変調整手段、及び、排気バルブの開弁時期、開弁期間あるいは弁リフト量を可変調整する排気バルブ可変調整手段の少なくとも一方を有することを特徴とする。
【００１８】
このように、吸気バルブ可変調整手段と排気バルブ可変調整手段の少なくとも一方を駆動して吸気バルブと排気バルブの少なくとも一方の開弁時期、開弁期間あるいは弁リフト量を調整してオーバーラップ量を定常運転時より増大させ、これによって、吸気バルブが開いた後の吸気負圧による排気引き戻し効果とオーバラップ中の二次エアの燃焼室への投入との相乗効果を利用して、二次エアおよび排気ガスをより多く燃焼室内に流入させ、燃焼室の未燃ガスを二次エアおよび逆流排気ガスと攪拌して再燃焼を促進させ、排気ガス昇温による燃焼安定化を早期に図れ、排気ガス中に残留する未燃ガスを低減させることができる。更に、オーバーラップ量を増大させることによって、吸気ポートまで逆流排気ガスが到達し、吸気ポート壁面が加熱されて壁面付着燃料の霧化を促進することができる。
【００１９】
請求項４の発明は、請求項１記載の内燃機関の排気浄化装置において、上記制御手段は、上記２次エア供給をすると共に排気バルブと吸気バルブのオーバーラップ量を増大させ、その上で所定時間経過後はオーバーラップ量を経過時間に比例して減少させて定常量に戻し、その戻し時点で上記２次エア供給装置を停止させることを特徴とする。
このように、オーバーラップ調整および二次エア供給処理の後、所定時間経過すると、排気ガス中の未燃ガスが低減した運転域に入っていることを考慮し、所定時間経過後の無駄なオーバーラップ調整および二次エア供給の駆動を停止し、無駄な出力ロスを防止できる。
【００２０】
請求項５の発明は請求項１記載の内燃機関の排気浄化装置において、上記制御手段は、上記２次エア供給装置を駆動すると共に排気バルブと吸気バルブのオーバーラップ量を増大させ、その上で所定時間経過前に車両の発進があると、同時点でオーバーラップ量を定常量に戻し、上記２次エア供給装置を停止させることを特徴とする。
このように、オーバーラップ調整および二次エア供給処理の上で、所定時間が経過する前に車両の発進があると、同時点でオーバーラップ量を定常量に戻し、２次エア供給装置を停止させ、発進後はオーバーラップ調整および二次エア供給の駆動を停止し、運転性重視の制御を許容することができる。
【００２１】
【発明の実施の形態】
図１は本発明の一実施形態としての内燃機関の排気浄化装置Ｍと、同装置を装備する内燃機関を示した。排気浄化装置Ｍは図１に示す内燃機関としての４サイクル４気筒ガソリンエンジン（以後、単にエンジン１と記す）に装着され、燃焼室２での排気の再燃焼を促進して、排気ガス改善を図るよう機能する。
ここで、エンジン１にはクランクシャフト３の回転力で駆動する吸排バルブ４、５が配備され、同吸排バルブ４、５により吸気路Ｒｉ側の吸気ポート６、排気路Ｒｅ側の排気ポート７を燃焼室２に断続的に連通する。更に、各気筒には燃料噴射弁８及び点火プラグ１０が装着される。
【００２２】
エンジン１は吸気ポート６に燃料噴射するマルチポイントインジェクション式を採り、各気筒の燃料噴射弁８には不図示の燃料供給系より等圧燃料が供給されており、エンジンコントローラ（以後単にコントローラ９と記す）内の燃料量制御部Ａ１が空燃比Ａ／Ｆその他の運転情報より導出した燃料噴射量Ｔｉｎｊ相当のパルス幅の燃料噴射出力Ｄ（Ｔｉｎｊ）を受けて噴射作動をする。
【００２３】
エンジン１の燃料量制御部Ａ１によって、定常運転域では理論空燃比Ａ／Ｆ（１５、０）を保持して混合気の燃焼を行うことで、排気路Ｒｅの前段触媒１１、主触媒１２の浄化効率を高レベルに保持する。なお、暖機運転時は後述の二次エアと未燃ガス（ＨＣ）の反応による排気昇温効果（触媒早期活性化）を期待し、空燃比がリッチ化される。
点火系の点火プラグ１０は点火回路１３に接続され、点火回路１３はコントローラ９内の点火制御部Ａ２から後述するように点火時期ＩＧＴの信号を受けた際に、同点火時期ＩＧＴに点火出力Ｄｉｇを点火プラグ１０に発し、点火駆動する。
【００２４】
吸気路Ｒｉはエアクリーナ２０からのエアをエンジン本体内の各気筒に流入させるもので、電子制御式のスロットルバルブ（以後単にＥＴＶ１４と記す）１４を備えた吸気管１５、その下流のサージタンク１６、そのサージタンクから分岐して延出する分岐吸気路ｒｉを備えた吸気マニホールド１７、各分岐吸気路ｒｉに連通するようシリンダヘッド１８内に形成され各気筒の吸気バルブ４の開時に燃焼室２に連通する吸気ポート６とを備える。ＥＴＶ１４はコントローラ９内に設けられたスロットル弁駆動部Ａ３から後述するように開弁出力Ｐｏを受けた際に、同弁開度に切換えるよう構成されている。
【００２５】
ＥＴＶ１４の回転軸にはスロットル開度センサ１９が装着され、これより発せられるスロットル開度θｓ信号はコントローラ９に入力される。更に、吸気管１５には吸入空気量Ｑａを検出するエアフローセンサ２２が装着され、吸入空気量Ｑａ信号はコントローラ９に入力される。
【００２６】
排気路Ｒｅは各気筒の燃焼室２の排気ガスを排気バルブ５の開時に排気ポート７より排気マニホールド２３内の各分岐排気路ｒｅに導き、更に、排気ガスを排気管４０の途中に設けた前段触媒１１とその下流の主触媒１２に順次導き、大気開放側に流下させている。前段触媒１１はＣＯ、ＨＣおよびＮＯｘを浄化する三元触媒で形成され、特に、小容量で早期に活性化して冷態始動直後の未燃ガス（ＨＣ）の浄化に寄与するよう形成され、主触媒１２は大容量の三元触媒で形成され、定常運転時の大容量の排気ガス浄化に寄与するよう形成される。
【００２７】
各気筒の排気ポート７には、二次エア供給装置２４のエアノズル２５が排気バルブ５の背部に向けて装着される。二次エア供給装置２４は、電動モータ２６で駆動のエアポンプ２７と、電動モータ２６の回転を可変駆動する駆動回路２８と、エアポンプ２７に連結されるエアノズル２５とを有する。エアポンプ２７はコントローラ９内の二次エア制御部Ａａから駆動回路２８に出力される制御信号に応じて駆動され、エアノズル２５から排気ポート７に二次エアを吹き出すことにより、燃焼室２より排気ポート７に流出する排気ガスの要部を燃焼室２に逆流させ、燃焼室２内の排気ガスを攪拌し、これにより燃焼室２内の未燃ガス（ＨＣ）を掻き出し、これら排気ガス中の未燃ガス（ＨＣ）を二次エアで再燃焼させる。
【００２８】
吸排気バルブ４、５を駆動する動弁系はＤＯＨＣ式の動弁装置４０であり、吸排カム２９、３０を備えた吸排カム軸３１、３２は図示しないベルト回転伝達手段を介してクランクシャフト３の回転を伝達され、回転駆動する。
図２に示すように、動弁装置４０は各気筒毎の吸気バルブ４、排気バルブ５を駆動する。ここでシリンダヘッド１８の軸受け部５１には吸排カム軸３１、３２及び吸排ロッカシャフト５２、５３が互いに並列配備され、吸排カム軸３１、３２に吸排カム２９、３０が配備される。
【００２９】
吸排ロッカシャフト５２、５３には吸排ロッカアーム５４、５５が枢支される。吸気ロッカアーム５４はその一端に枢支するローラ５６を介して吸気カム２９に当接し、他端が吸気バルブ４に当接する。排気ロッカアーム５５はその一端に枢支するローラ５７を介して排気カム３０に当接し、他端が排気バルブ５に当接する。
【００３０】
図２に示すように、吸カム軸３１は吸気カム２９の開弁時期（開弁中心時期）θＩｃを可変調整する吸気バルブ可変調整手段である吸気位相調整機構３３を備える。同じく、排カム軸３２は排気バルブ５の開弁時期（開弁中心時期）θＥｃ（図３参照）を可変調整する排気バルブ可変調整手段である排気位相調整機構３４を備える。これら吸排気位相調整機構３３、３４によりバルブ調整手段が構成される。
【００３１】
コントローラ９内には二次エア供給装置２４の制御部である二次エア制御部Ａａが配備され、これはエンジンの運転情報よりエンジン１が冷態判定温度Ｔｃを下回ると判定すると、二次エア供給装置２４を駆動するよう制御する。
コントローラ９内には吸気及び排気バルブ可変調整手段である吸排気位相調整機構３３、３４の制御部である吸排気バルブ可変調整部Ａｂが配備され、これはエンジンの運転情報よりエンジン１が冷態判定温度Ｔｃを下回ると判定すると、排気バルブ５の開弁時期（開弁中心時期）を定常運転時の開弁時期θＥｃより遅角量−ΔθａずらせたθＥｃ１に設定し、吸気バルブ４と排気バルブ５のオーバーラップ量を定常運転時の量Ｂ０より増大したオーバーラップ量Ｂ１に制御するよう機能する。
【００３２】
図２に示すように、吸排気位相調整機構３３、３４は排カム軸３２の前端部に設けられたスプロケット３５ｉ、３５ｅと、同スプロケットと吸排カム軸３１、３２とを相対回転可能に連結する位相制御用アクチュエータ３６ｉ、３６ｅとを備える。スプロケット３５ｉ、３５ｅは図示せぬタイミングベルトを介してクランクシャフト３に連結される。位相制御用アクチュエータ３６ｉ、３６ｅは電磁式の回転型アクチュエータからなり、コントローラ９内の吸排気バルブ可変調整部Ａｂからの制御信号Ｓｔｉ、Ｓｔｅを受けた各駆動回路３７ｉ、３７ｅによって駆動制御される。これにより、吸排バルブ４、５のリフトにおける開弁時期（開弁中心時期）θＩｃ、θＥｃが遅角あるいは進角される。この吸排気位相調整機構３３、３４の制御状態である吸排カム軸３１、３２の回転位置は駆動軸センサ３８ｉ、３８ｅによって検出され、コントローラ９に出力される。
【００３３】
エンジン１はその給排気系及び燃料供給系、点火系をコントローラ９によって制御される。
コントローラ９は運転情報検出手段によりエンジン１の運転情報を検出する。運転情報検出手段としての、クランク角センサ４１は単位クランク角Δθｃ及びエンジン回転数Ｎｅを、スロットル開度センサ１９はスロットル開度θｓを、エアフローセンサ２２は吸入空気量Ｑａを、車速センサは車速Ｖｃを、空燃比センサ４３は空燃比Ａ／Ｆを、シリンダブロック４４に装着された水温センサ４５は冷却水の水温ｗｔをそれぞれコントローラ９に入力する。
【００３４】
ここで、コントローラ９のスロットル弁駆動部Ａ３は、アクセルペダル開度θａ、車速Ｖｃ、冷却水の水温ｗｔ、等に応じた通常時弁開度Ｐｏ、或いは暖機時弁開度Ｐｏを求め、その上で、演算された通常時或いは暖機時弁開度Ｐｏ相当の各開弁出力をＥＴＶ１４に出力し、吸気量制御処理を行っている。
コントローラ９の燃料量制御部Ａ１は、定常時にエンジン回転数Ｎｅとスロットル開度θｓに応じた基本燃料噴射量Ｔｂを求め、これに空燃比Ａ／Ｆ、水温ｗｔ等の補正値ＴＡ／Ｆ、Ｔｗｔを加えて燃料噴射量Ｔｉｎｊ（＝Ｔｂ＋ＴＡ／Ｆ＋Ｔｗｔ）を導出する。その上で、演算された燃料噴射量Ｔｉｎｊ相当の出力信号Ｄを燃料噴射弁８に出力し、燃料噴射量制御を行っている。
【００３５】
ここで、暖機運転時の内、後述の二次エア供給時には、この二次エアと未燃ガス（ＨＣ）の反応による排気昇温効果（触媒早期活性化）を期待し、空燃比Ａ／Ｆの補正値ＴＡ／Ｆがリッチ用の補正値ＴＡ／Ｆｒで燃料噴射量Ｔｉｎｊが演算され、リッチ化された燃料供給がなされる。
コントローラ９の点火制御部Ａ２は、定常時において、スロットル開度θｓ等に応じた基本点火時期ＩＧＴｂと運転状態に応じた遅角補正値ΔＩＧより点火時期ＩＧＴを導出する。その上で、演算され点火時期ＩＧＴ相当の出力信号Ｄｉｇを点火プラグ１０にそれぞれ出力し点火処理を行っている。
【００３６】
次に、図１に示す内燃機関の排気浄化装置Ｍの作動をコントローラ９が行なう図４の第１冷態始動制御ルーチンに沿って説明する。
コントローラ９はメインスイッチのオンと同時に図示しないメインルーチンに沿ってエンジン１の燃料系、点火系、吸気系の制御を行ない、その途中で冷態始動制御ルーチンの処理を行なう。
【００３７】
第１冷態始動制御ルーチンに達すると、ステップｓ１で始動判定処理を行ない、始動判定後にステップｓ２に進む。この始動判定処理では、スタータ駆動後の所定時間内におけるエンジン回転数Ｎｅが始動判定回転数Ｎｅｓ、例えば３００ｒｐｍを越えたか否か判断し、始動前はメインルーチンにリターンし、始動完了後にはステップｓ２に達する。ここでは冷却水温度Ｔｗが冷態判定温度Ｔｃ１（例えば、２５℃）を下回るか否か判断し、下回るとステップｓ３に、暖気後始動時にはＮｏ側のステップｓ７に進み、後述するように、各々の制御が停止され、メインルーチンにリターンする。
【００３８】
ステップｓ３では二次エア制御部Ａａとして機能し、ここでは冷態判定温度Ｔｃ１以下であり、二次エア供給装置２４の駆動回路に定常回転信号を出力し、駆動回路が電動モータ２６を定常回転数で駆動し、エアポンプ２７を定常吹出し圧Ｐｎ１で駆動する。
これによりエアノズル２５から排気ポート７に定常吹出し圧Ｐｎ１の二次エアを吹き出し、排気行程で燃焼室２より排気ポート７に流出する排気ガスを燃焼室２に逆流させる。
【００３９】
ステップｓ３よりステップｓ４に達すると、ここでは吸排気バルブ可変調整部Ａｂとして機能する。ここでは吸気位相調整機構３３の位相制御用アクチュエータ３６によりスプロケット３５ｉと吸カム軸３１を基準開弁時期（開弁中心時期）θＩｃに保持する。一方、排気位相調整機構３４の位相制御用アクチュエータ３６ｅによりスプロケット３５ｅに対して定常運転時の開弁時期θＥｃより遅角量−ΔθａずらせたθＥｃ１に切換え保持する。
【００４０】
これにより、図３に示すように、基準開弁時期（開弁中心時期）θＩｎの吸気バルブ４（図３ではＩＮと記す）に対して遅角量−Δθａずらせた開弁時期θＥｃ１で駆動する排気バルブ５（図３ではＥＸと記す）はオーバーラップ量Ｂ１を保つようにして駆動する。
【００４１】
この時、定常運転時より増大したオーバーラップ量Ｂ１でのオーバーラップ増大モードＵ１での運転期間において、吸気バルブ４が開いた後の吸気負圧による排気引き戻し効果と、二次エアの燃焼室２内への投入との相乗効果により、オーバラップ中に二次エアおよび逆流排気ガスをより多く燃焼室内に取り込み、燃焼室の未燃ガスを二次エアおよび逆流排気ガスと攪拌し、未燃ガス（ＨＣ）を掻き出し、これらを攪拌し、二次エアおよび逆流排気ガスで未燃ガス（ＨＣ）を再燃焼させ、排出未燃ガス（ＨＣ）を極力低減することができる。更に、オーバーラップ量Ｂ１を増大させることによって、吸気ポート６まで逆流排気ガスが到達し、吸気ポート壁面が加熱されて壁面付着燃料の霧化を促進することができる。
【００４２】
ステップｓ４よりステップｓ５に達すると、ここでは所定経過時間ｔｏのカウントタイマＴＩＭ１を駆動し、ステップｓ６で経過前はそのままメインルーチンにリターンし、経過した時点でステップｓ７に進み、ここで二次エアの吹出し停止処理と、オーバーラップ増大モードＵ１での吸排気位相調整機構３４、３４の駆動を停止し、定常モード（吸排バルブ４、５を基準開弁時期θＩｎ、θＥｎで駆動）Ｕ０に戻し処理し、メインルーチンに戻る。
【００４３】
このように、図１の内燃機関の排気浄化装置Ｍではエンジン冷態始動時において、冷態判定温度Ｔｃ１以下では、オーバーラップ増大モードＵ１での運転期間において、吸気バルブ４が開いた後の吸気負圧による排気引き戻し効果と、二次エアの燃焼室２内への投入との相乗効果により、オーバラップ中に二次エアをより多く燃焼室内に取り込みでき、燃焼室２の排気行程の時点で排出されようとしていた未燃ガスを二次エアおよび逆流排気ガスと十分に攪拌して再燃焼させ、排気ガス中に残留する未燃ガスを低減させることができる。更に、オーバーラップ量Ｂ１を増大させることによって、吸気ポート６まで逆流排気ガスが到達し、吸気ポート壁面が加熱されて壁面付着燃料の霧化を促進することができる。
【００４４】
上述のところにおいて、第１冷態始動制御ルーチンでステップｓ２で、冷却水温度Ｔｗが冷態判定温度Ｔｃ１（例えば、２５℃）を下回るか否か判断し、下回るとステップｓ３以下の制御を行なっていたが、これに代えて図５に示すような第２冷態始動制御ルーチンを実行しても良い。ここで、第２冷態始動制御ルーチンにおいて、第１冷態始動制御ルーチンでの処理と同様になされる処理には同一ステップ符号を付し、重複説明を略す。
【００４５】
第２冷態始動制御ルーチンに達すると、ステップｓ１で始動判定処理を行ない、ステップｓ２では冷却水温度Ｔｗが冷態判定温度Ｔｃ１を下回るか否か判断し、下回るとステップｓ１０に、暖気後始動時にはステップｓ７に進み、後述するように、各々の制御が停止され、メインルーチンにリターンする。ステップｓ１０では、冷却水温度Ｔｗが冷態判定温度Ｔｃ１より更に低い寒冷判定温度（例えば、０℃）を下回るか否か判断し、Ｎｏでステップｓ３に、Ｙｅｓでステップｓ１１に進む。
【００４６】
ステップｓ３では、二次エア供給装置２４の駆動回路に定常回転信号を出力し、エアポンプ２７を定常吹出し圧Ｐｎ１で駆動し、エアノズル２５から排気ポート７に定常吹出し圧Ｐｎ１の二次エアを吹き出し、燃焼室２内の排気ガスを攪拌し、排気ガス中の未燃ガス（ＨＣ）を再燃焼させる。
【００４７】
ステップｓ４に達すると吸排気バルブ可変調整部Ａｂとし、吸気位相調整機構３３の位相制御用アクチュエータ３６ｉにより基準開弁時期θＩｎを保持し、排気位相調整機構３４の位相制御用アクチュエータ３６ｅにより定常運転時の開弁時期θＥｃより遅角量−ΔθａずらせたθＥｃ１に切換え、図３に示すようにオーバーラップ増大モードＵ１で排気バルブ５を駆動する。
【００４８】
オーバーラップ増大モードＵ１での運転期間において、吸気バルブ４が開いた後の吸気負圧による排気引き戻し効果と、二次エアの燃焼室２内への投入との相乗効果により、二次エアをより多く燃焼室内に取り込み、未燃ガスを二次エアと攪拌し、未燃ガス（ＨＣ）を掻き出し、排気ガス中の未燃ガス（ＨＣ）を再燃焼させ、排出未燃ガス（ＨＣ）を極力低減することができる。
【００４９】
ステップｓ５に達するとカウントタイマＴＩＭ１を駆動し、ステップｓ６でｔ０経過を待ち、ステップｓ７に進み、二次エアの吹出し停止処理と、オーバーラップ増大モードＵ１を停止し、定常モードＵｏに戻し処理し、メインルーチンに戻る。
ステップｓ１０で冷却水温度Ｔｗが寒冷判定温度（例えば、０℃）Ｔｃ２を下回ると判断してステップｓ１１に達する。
【００５０】
ここでは寒冷判定温度（例えば、０℃）Ｔｃ２を下回ることより、燃焼不安定化を抑制すべく、二次エア供給装置２４の駆動回路２８に高圧回転信号を出力し、駆動回路２８が電動モータ２６を高圧回転数で駆動し、エアポンプ２７を高吹出し圧で駆動する。この後、ステップｓ４〜７に順次進む。
【００５１】
この場合も、図３に示すようにオーバーラップ増大モードＵ１で、吸気バルブ４が開いた後の吸気負圧による排気引き戻し効果と二次エアの燃焼室２内への投入との相乗効果により、未燃ガスを二次エアおよび逆流排気ガスと攪拌し、未燃ガス（ＨＣ）を掻き出す機能が増し、排気ガス中の未燃ガス（ＨＣ）を再燃焼させ、排出未燃ガス（ＨＣ）を極力低減することができ、極低温時の燃焼安定性を確保できる。更に、オーバーラップ量Ｂ１を増大させることによって、吸気ポート６まで逆流排気ガスが到達し、吸気ポート壁面が加熱されて壁面付着燃料の霧化を促進することができる。
【００５２】
上述のところにおいて、第１、第２の冷態始動制御ルーチンでのステップｓ６では、所定経過時間ｔｏの経過した時点で、二次エアの吹出し停止処理と、開弁期間Ｖｅｏ・リフト可変調整手段による開弁期間Ｖｅｏを定常開弁モードに戻し処理していたが、所定経過時間ｔｏの経過前に冷却水Ｔｗが冷態判定温度Ｔｃ１以上となると、その時点でステップｓ７に進み、各々の制御が停止される。
【００５３】
上述のところにおいて、第２冷態始動制御ルーチンでのステップｓ１０では、寒冷判定温度Ｔｃ２を順次下回るか否かでエアポンプ２７を定常吹出し圧Ｐｎ１あるいは高吹出し圧Ｐｎ２で駆動していたが、これに代えて、図６に示すように、ステップｓ３’、ｓ１１’で示す処理を行なってもよい。
【００５４】
ここでは、冷却水温度Ｔｗが寒冷判定温度Ｔｃ２を上回る比較的緩やかな低温と判断すると、ステップｓ３’に進み、ここで所定経過時間ｔｏのカウントタイマＴＩＭ１のカウント値ｔｎに応じたエアポンプ２７の吹出し圧Ｐｅｖを吹出し圧−経過時間マップｍｐ（図７参照）より演算し、同吹出し圧Ｐｅｖを確保できる駆動出力で、電動モータ２６を駆動し、エアポンプ２７の吹出し圧を増減調整する。この吹出し圧−経過時間マップｍｐでは、燃焼安定化のため、経過時間初期ｅ１の吹出し圧ＰｅｖＬを高レベルに設定し、燃焼室２内の未燃ガス（ＨＣ）と二次エアの攪拌の程度を高める。その後の後期ｅ２においては時間経過に応じて電動モータ２６の回転レベル、即ち、攪拌の程度を徐々に低減させ、時間経過に応じた無駄な電動モータ２６のエネルギロス増を排除している。なお、寒冷判定温度Ｔｃ２以下でステップｓ１０よりステップｓ１１’に達した場合もステップｓ３’と同様に制御されるが、その吹出し圧−経過時間マップｍｐでの吹出し圧ＰｅｖＨがより高レベルに設定されることとなり、同様に時間経過に応じた無駄なエネルギロス増を排除している。
【００５５】
上述のところにおいて、第１、２冷態始動制御ルーチンでのステップｓ４では、吸排気バルブ可変調整部Ａｂとし、排気位相調整機構３４の位相制御用アクチュエータ３６ｅにより定常運転時の開弁時期θＥｃより遅角量−ΔθａずらせたθＥｃ１に排気バルブ５を切換え、図３に示すようにオーバーラップ増大モードＵ１で排気バルブ５を駆動した。これに対し、図８（ａ）、（ｂ）に示すように、吸排気バルブ可変調整部Ａｂとし、吸気位相調整機構３３の位相制御用アクチュエータ３６ｉにより定常運転時の開弁時期θＩｃより進角量＋ΔθａずらせたθＩｃ２に吸気バルブ４（図８（ｂ）ではＩＮと記す）を切換え、オーバーラップ増大モードＵ１で吸気バルブ４を駆動してもよい。
【００５６】
更に、図９（ａ）、（ｂ）に示すように、吸排気バルブ可変調整部Ａｂとし、吸排気位相調整機構３４、３４の位相制御用アクチュエータ３６ｉ、３６ｅにより定常運転時の開弁時期θＩｃ、θＥｃより進角量＋Δθａ、遅角量−ΔθａずらせたθＩｃ３、θＥｃ３に吸気バルブ４を切換え、オーバーラップ増大モードＵ１で吸排バルブ４、５（図９（ｂ）ではＩＮ、ＥＸと記す）を駆動してもよい。これらの場合も、図１の装置と同様の作用効果が得られる。
【００５７】
図１の内燃機関の排気浄化装置Ｍでは吸排カム２９、３０がそれぞれ単一の動弁装置４０であったが、これに代えて、図１０に示すように吸排カムがそれぞれ２つ装備されたカム２段切換え動弁装置６０を用い排気浄化装置Ｍａ（図１の排気浄化装置Ｍの記載を同様に用いて説明する）を構成しても良い。
なお、ここでの排気浄化装置Ｍａはカム２段切換え動弁装置６０以外の部分が図１の内燃機関の排気浄化装置Ｍとほぼ同様の構成部材を備え、ここでは、同一部材に同一符号を付し重複説明を略す。
【００５８】
カム２段切換え動弁装置６０は、シリンダヘッド１５の軸受け部５１にはカム軸３１、３２及び吸排ロッカシャフト６１、６２が互いに並列配備され、カム軸３１、３２に吸気カム２９ａ、２９ｂと排気カム３０ａ、３０ｂがそれぞれ配備される。吸気ロッカシャフト６１の軸部６１１には吸気ロッカアーム６４１が一体結合され、同吸気ロッカアーム６４１はその先端部で吸気バルブ４を駆動する。
【００５９】
吸気ロッカシャフト６１はその軸部６１１に大アーム６３のボス部６３１が枢支され、その隣に小アーム６４２が一体的に取り付けられる。大アーム６３の揺動端はローラ６５を介し大吸気カム２９ａに当接し、小アーム６４２の揺動端はローラ６６を介し小吸気カム２９ｂに当接する。
大アーム６３のボス部６３１と対向する軸部６１１内には、突出し可能に収容され、油路７２からの圧油で油圧駆動する切換えピン７３が配備される。
【００６０】
排気ロッカシャフト６２の軸部６２１には排気ロッカアーム６８１が一体結合され、同排気ロッカアーム６８１はその先端部で排気バルブ５を駆動する。排気ロッカシャフト６２はその軸部６２１に大アーム６７のボス部６７１が枢支され、その隣に小アーム６８２が一体的に取り付けられる。大アーム６７の揺動端はローラ６９を介し大排気カム３０ａに当接し、小アーム６８２の揺動端はローラ７１を介し小排気カム３０ｂに当接する。
大アーム６７のボス部６７１と対向する軸部６２１内には、突出し可能に収容され、油路７４からの圧油で油圧駆動する切換えピン７５が配備される。
【００６１】
各油路７２、７４はシリンダヘッド１８側に連続する制御油路７２ａ、７４ａを介し、オイルポンプ７６、オイルパン７７に連通する。ここで制御油路７２ａ、７４ａには切換え弁である電磁弁７８、７９が介装され、各電磁弁がコントローラ９ａにより駆動制御されることで切換えピン７３、７５の切換え、即ち、大小吸気カム、２９ａ、２９ｂ、大小排気カム３０ａ、３０ｂの切換えがなされる。なお、ここでは電磁弁７８、７９がオフで、切換えピン７３、７５が非突出し状態で、大アーム６３、６７が空作動して小カム２９ｂ、３０ｂと小アーム６４２、６８２の働きにより、図１１に破線で示すように、吸排バルブ４、５（図１１ではＩＮ、ＥＸと記す）が定常モードＵ０で駆動する。一方、電磁弁７８、７９オンで、切換えピン７３、７５が突出し作動して、大アーム６３、６７が大吸気、大排気カム２９ａ、３０ａにより駆動し、図１１に実線で示すように、吸排バルブ４、５がオーバーラップ増大モードＵａ１で駆動する。
【００６２】
なお、両ローラ６６、６８の半径は同一で、大吸気カム２９ａ、大排気カム３０ａと小吸気カム２９ｂ、小排気カム３０ｂは突出し部以外の円筒部は同一半径で形成される。
このようなカム２段切換え動弁装置６０は、図１１に示すように、切換えピン７３、７５の退却時には小吸気、小排気カム２９ｂ、３０ｂにより定常モードＵ０で吸排バルブ４、５が駆動され、切換えピン７３、７５の突出し時には大吸気、大排気カム２９ａ、３０ａにより、オーバーラップ増大モードＵａ１で吸排バルブ４、５が駆動し、未燃ガスと二次エアの撹拌を促進し、燃焼安定性確保と排ガス改善とを図ることができる。
【００６３】
このような内燃機関の排気浄化装置Ｍａはコントローラ９ａにより制御される。このコントローラ９ａは上述のコントローラ９と比較し図１２に示す第３冷態始動制御ルーチン以外の制御が同様のため、ここでは重複説明を略す。
図１２に示す第３冷態始動制御ルーチンに達すると、ステップｓ１で始動判定処理を行ない、ステップｓ２では冷却水温度Ｔｗが冷態判定温度Ｔｃ１を下回るか否か判断し、下回るとステップｓ３に、暖気後始動時にはＮｏ側のステップｓ７に進み、各々の制御が停止され、メインルーチンにリターンする。ステップｓ３では、二次エア供給装置２４の駆動回路に定常回転信号を出力し、エアポンプ２７を定常吹出し圧Ｐｎ１で駆動し、エアノズル２５から排気ポート７に定常吹出し圧Ｐｎ１の二次エアを吹き出し、燃焼室２内の排気ガスを攪拌し、排気ガス中の未燃ガス（ＨＣ）を再燃焼させる。
【００６４】
ステップｓ４に達すると吸排気バルブ可変調整部Ａｂ’とし、吸排気位相調整機構３４、３４の位相制御用アクチュエータ３５ｉ、３５ｅにより基準開弁時期θＩｃ、θＥｃを保持する。
更に、カム２段切換え動弁装置６０を駆動制御し、即ち、電磁弁７８、７９オンで切換えピン７３、７５が突出し作動して、大アーム６３、６７が大吸気、大排気カム２９ａ、３０ａにより駆動し、吸排バルブ４、５がオーバーラップ増大モードＵａ１（図１１参照）で駆動する。
【００６５】
このオーバーラップ増大モードＵａ１での運転期間において、二次エアの投入を受けていること、吸気バルブ４が開いた後の吸気負圧による排気引き戻しとの相乗効果により、二次エアをより多く燃焼室内に取り込み、未燃ガスを二次エアおよび逆流排気ガスと攪拌し、未燃ガス（ＨＣ）を掻き出し、排気ガス中の未燃ガス（ＨＣ）を再燃焼させ、排出未燃ガス（ＨＣ）を極力低減することができる。更に、オーバーラップ量Ｂ１を増大させることによって、吸気ポート６まで逆流排気ガスが到達し、吸気ポート壁面が加熱されて壁面付着燃料の霧化を促進することができる。
【００６６】
ステップｓ５に達するとカウントタイマＴＩＭ１を駆動し、ステップｓ６でｔ０経過を待ち、ステップｓ７に進み、二次エアの吹出し停止処理と、オーバーラップ増大モードＵａ１を停止し、定常モードＵ０に戻し処理し、メインルーチンに戻る。
【００６７】
上述のところにおいて、内燃機関の排気浄化装置Ｍａの第３冷態始動制御ルーチンでは、ステップｓ４において、両電磁弁７８、７９オンで両切換えピン７３、７５が突出し作動して、大アーム６３、６７が大吸気、大排気カム２９ａ、３０ａにより駆動し、吸排バルブ４、５がオーバーラップ増大モードＵａ１（図１１参照）で駆動していた。しかし、これに代えて、図１３（ａ）、（ｂ）に示すようにステップｓ４’において、電磁弁７９オンで切換えピン７５が突出し作動して、大アーム６７が大排気カム３０ａにより駆動し、排気弁５がオーバーラップ増大モードＵｂ１で駆動するとしてもよい。逆に、図１４（ａ）、（ｂ）に示すようにステップｓ４”において、電磁弁７８オンで切換えピン７３が突出し作動して、大アーム６３が大吸気カム２９ａにより駆動し、吸気弁４がオーバーラップ増大モードＵｃ１で駆動するとしてもよい。これらの場合も、図１の装置と同様の作用効果が得られる。
【００６８】
さらに、図１５（ａ）、（ｂ）に示すように、ステップｓ４’’’において、吸排気バルブ可変調整部Ａｂ’とし、吸排気位相調整機構３３、３４の位相制御用アクチュエータ３５ｉ、３５ｅを進角量＋Δθａおよび遅角量−Δθａを加えて定常時の開弁時期θＩｃ、θＥｃを開弁時期θＩｃ４、θＥｃ４に切換え保持する。これに加え、両電磁弁７８、７９オンで両切換えピン７３、７５が突出し作動して、大アーム６３、６７が大吸気、大排気カム２９ａ、３０ａにより駆動する。この結果、吸排バルブ４、５がオーバーラップＢ１のオーバーラップ増大モードＵｄ１で駆動するとしてもよい。これにより、カム２段切換え動弁装置６０に加え、吸気位相調整機構３３が吸気バルブ４の開弁時期、開弁期間あるいは弁リフト量を可変調整する吸気バルブ可変調整手段として機能し、排気位相調整機構３４が排気バルブの開弁時期、開弁期間あるいは弁リフト量を可変調整する排気バルブ可変調整手段として機能する。この場合も、図１の装置と同様の作用効果が得られる。
【００６９】
上述のところにおいて吸気バルブ可変調整手段、排気バルブ可変調整手段としてカム２段切換え動弁装置６０に吸排気位相調整機構３３、３４を加えた構成を示したが、このうち、カム２段切換え動弁装置６０に代えて、特開２００２−２５６９０５号公報に開示されるリフト・作動角可変機構を用い、開弁期間あるいはバルブリフト量の少なくとも一つを可変調整してもよい。この場合も、図１０のカム２段切換え動弁装置６０を用いた排気浄化装置Ｍａと同様の作用効果が得られる。
【００７０】
【発明の効果】
以上のように、本発明は、吸気バルブが開いた後の吸気負圧による排気引き戻し作用とオーバラップ中の二次エアの燃焼室への投入との相乗効果を利用して、二次エアおよび排気ガスをより多く燃焼室内に流入させ、燃焼室の未燃ガスを二次エアおよび逆流排気ガスと攪拌して再燃焼を促進させ、排気ガス昇温による燃焼安定化を早期に図れ、排気ガス中に残留する未燃ガスを低減させることができる。更に、オーバーラップ量を増大させることによって、吸気ポートまで逆流排気ガスが到達し、吸気ポート壁面が加熱されて壁面付着燃料の霧化を促進することができる。
【００７１】
請求項２の発明は、吸気バルブ可変調整手段と排気バルブ可変調整手段の少なくとも一方が吸気バルブと排気バルブの少なくとも一方の開弁期間或いは弁リフト量を可変調整してオーバーラップ量を定常運転時より増大させ、これによって、吸気バルブが開いた後の吸気負圧による排気引き戻し作用とオーバラップ中に逆流方向に吹出す二次エアとの相乗効果を利用して、二次エアおよび排気ガスをより多く燃焼室内に流入させ、燃焼室の未燃ガスを二次エアおよび逆流排気ガスと攪拌して再燃焼を促進させ、排気ガス昇温による燃焼安定化を早期に図れ、排気ガス中に残留する未燃ガスを低減させることができる。更に、オーバーラップ量を増大させることによって、吸気ポートまで逆流排気ガスが到達し、吸気ポート壁面が加熱されて壁面付着燃料の霧化を促進することができる。
【００７２】
請求項３の発明は、吸気バルブ可変調整手段と排気バルブ可変調整手段の少なくとも一方を駆動して吸気バルブと排気バルブの少なくとも一方の開弁時期、開弁期間あるいは弁リフト量を調整してオーバーラップ量を定常運転時より増大させ、これによって、吸気バルブが開いた後の吸気負圧による排気引き戻し作用とオーバラップ中に逆流方向に吹出す二次エアとの相乗効果を利用して、二次エアおよび排気ガスをより多く燃焼室内に流入させ、燃焼室の未燃ガスを二次エアおよび逆流排気ガスと攪拌して再燃焼を促進させ、排気ガス昇温による燃焼安定化を早期に図れ、排気ガス中に残留する未燃ガスを低減させることができる。更に、オーバーラップ量を増大させることによって、吸気ポートまで逆流排気ガスが到達し、吸気ポート壁面が加熱されて壁面付着燃料の霧化を促進することができる。
【００７３】
請求項４の発明は、オーバーラップ調整および二次エア供給処理の後、所定時間経過すると、排気ガス中の未燃ガスが低減した運転域に入っていることを考慮し、所定時間経過後の無駄なオーバーラップ調整および二次エア供給の駆動を停止し、無駄な出力ロスを防止できる。
【００７４】
請求項５の発明は、オーバーラップ調整および二次エア供給処理の上で、所定時間が経過する前に車両の発進があると、同時点でオーバーラップ量を定常量に戻し、２次エア供給装置を停止させ、発進後はオーバーラップ調整および二次エア供給の駆動を停止し、運転性重視の制御を許容することができる。
【図面の簡単な説明】
【図１】本発明の一実施形態としての内燃機関の排気浄化装置を装備したエンジンの概略構成図である。
【図２】図１の内燃機関の排気浄化装置内の動弁装置の要部平面図である。
【図３】図１の内燃機関の排気浄化装置の吸排気弁の開弁モード説明図である。
【図４】図１の内燃機関の排気浄化装置が行なう第１冷態始動制御ルーチンのフローチャートである。
【図５】図１の内燃機関の排気浄化装置が行なう第２冷態始動制御ルーチンのフローチャートである。
【図６】図１の内燃機関の排気浄化装置が行なう第２冷態始動制御ルーチンの他の変形例である。
【図７】図１の内燃機関の排気浄化装置が行なう冷態始動制御ルーチンの第２変形例で用いる吹出し圧−経過時間マップｍｐの特性図である。
【図８】図１の内燃機関の排気浄化装置が行なう第２冷態始動制御ルーチンの他の変形例で、（ａ）はステップ４’を、（ｂ）は吸排気弁の開弁モード説明図を示す。
【図９】図１の内燃機関の排気浄化装置が行なう第２冷態始動制御ルーチンの他の変形例で、（ａ）はステップ４”を、（ｂ）は吸排気弁の開弁モード説明図を示す。
【図１０】本発明の他の実施形態としての内燃機関の排気浄化装置で用いる動弁装置の要部平面図である。
【図１１】本発明の他の実施形態としての内燃機関の排気浄化装置で用いる吸排気弁の開弁モード説明図である。
【図１２】図１０の動弁装置を有する内燃機関の排気浄化装置が行なう第３冷態始動制御ルーチンのフローチャートである。
【図１３】図１２の第３冷態始動制御ルーチンの変形例で、（ａ）はステップ４’を、（ｂ）は吸排気弁の開弁モード説明図を示す。
【図１４】図１２の第３冷態始動制御ルーチンの他の変形例で、（ａ）はステップ４”を、（ｂ）は吸排気弁の開弁モード説明図を示す。
【図１５】図１２の第３冷態始動制御ルーチンの他の変形例で、（ａ）はステップ４’’’を、（ｂ）は吸排気弁の開弁モード説明図を示す。
【図１６】内燃機関の二次エア供給装置の概略図である。
【図１７】内燃機関の二次エア供給装置の機能説明図である。
【符号の説明】
１、１ａ エンジン
５ 排気バルブ
７ 排気ポート
９、９ａ コントローラ（制御手段）
２４ 二次エア供給装置
４０ 動弁装置
４５ 水温センサ（運転情報検出手段）
６０ カム２段切換え動弁装置
Ａａ 二次エア制御部
Ａｂ 排気バルブ可変調整部
Ｂ０、Ｂ１ オーバーラップ量
Ｍ、Ｍａ 内燃機関の排気浄化装置
Ｒｉ 吸気路
Ｒｅ 排気路
Ｔｗ 冷却水温（運転情報）
Ｔｃ１ 冷態判定温度
Ｕ１ オーバーラップ増大モード
Ｐｎ１ 定常吹出し圧[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exhaust gas purification apparatus for an internal combustion engine that can suppress the amount of unburned gas in the exhaust gas of the internal combustion engine, and in particular, secondary air is injected into the combustion chamber from the exhaust port side to reburn the unburned gas. The present invention relates to an exhaust purification device for an internal combustion engine.
[0002]
[Prior art]
In an internal combustion engine, unburned gas (HC) remaining in the combustion stroke tends to be discharged together with the exhaust gas in the exhaust stroke. For example, as shown in FIG. 17, when unburned gas (HC) enters the combustion chamber side gap (clevis) p1 between the cylinder head 100 and the cylinder block 110 or the combustion chamber side gap (clevis) p2 between the piston and the cylinder wall, They do not reach the flame and remain unburned. In addition, deposits, which are burned out over time, accumulate on the top peripheral edge p3 of the piston, and if unburned gas (HC) also enters the gaps in the deposit product, the flame does not reach this and remains unburned. Furthermore, if unburned gas adheres to the oil film on the cylinder wall p4, it remains unburned. Further, since the temperature of the combustion chamber wall 101 of the cylinder head 100 is low, the flame extinguishes near the combustion chamber wall 101, and unburned gas (HC) near the combustion chamber wall of the cylinder head tends to remain unburned.
[0003]
As described above, the unburned gas (HC) that has entered the non-flame reaching region in the combustion stroke is exhausted from the non-flame reaching region through the exhaust port in the exhaust stroke in which the pressure in the combustion chamber is reduced, and the exhaust gas deteriorates. . In particular, during the cold start of the internal combustion engine, a relatively rich air-fuel mixture is supplied to ensure its combustion stability, and the amount of unburned gas (HC) remaining unburned in the combustion stroke increases. It is easy to do.
[0004]
Therefore, as a countermeasure, a pre-catalyst that is activated early on an exhaust passage (not shown) and a main catalyst behind the pre-catalyst are arranged to suppress the emission of unburned gas (HC) immediately after a cold start. However, this catalyst alone does not provide a sufficient measure for preventing unburned gas (HC) from being discharged during a cold start in which the catalyst temperature is low and the activity is insufficient.
[0005]
Therefore, in the exhaust stroke, as shown in FIG. 16, secondary air will be injected toward the combustion chamber 160 from the back side of the exhaust valve 150 by the nozzle 140 mounted in the exhaust port 130, and will be discharged from the combustion chamber 160. The exhaust gas flowing back into the combustion chamber is agitated, whereby the unburned gas (HC) remaining before being discharged from the combustion chamber 160 is reburned by the secondary air. The unburned gas (HC), which reaches the flame reaching region from the non-flame reaching region and is about to be discharged from the combustion chamber, is re-burned by the secondary air in accordance with the conversion to suppress the discharge of the unburned gas.
[0006]
For example, Japanese Patent Application Laid-Open No. 8-158858 (Patent Literature 1) discloses that in order to reduce unburned gas (HC) after a cold start, secondary air is blown and an exhaust flow valve (shutter) is closed. Since the increase in the internal EGR amount causes combustion instability, the exhaust valve timing is advanced to reduce the amount of overlap with the intake valve, preventing the internal EGR amount from excessively increasing, and stabilizing combustion. It is trying to make it.
[0007]
Further, Japanese Patent Application Laid-Open No. 2001-263050 (Patent Document 2) discloses that after a cold start, an exhaust valve is advanced to increase the amount of overlap between an intake valve and an exhaust valve, and that unburned gas flows into an exhaust pipe. And promoting secondary combustion of unburned gas (HC) in the exhaust pipe, thereby activating the catalyst early and suppressing unburned gas emission. .
[0008]
[Patent Document 1]
JP-A-8-158858
[Patent Document 2]
JP 2001-263050 A
[0009]
[Problems to be solved by the invention]
As described above, the technique of Patent Document 1 is to stabilize combustion by advancing the exhaust valve timing in order to prevent combustion instability due to an excessive increase in the internal EGR amount due to blowing secondary air. The technology disclosed in Patent Document 2 aims to activate the catalyst early by promoting the combustion of unburned gas (HC) in the exhaust pipe, thereby suppressing unburned gas (HC) emission.
[0010]
As described above, the technologies of both patents are expected to have an exhaust gas temperature increasing effect (early catalyst activation) due to the reaction between the secondary air and the unburned gas (HC), and have a rich air-fuel ratio in the secondary air injection operation region. It is a technology that takes into account the point that it is difficult to optimize the degree of conversion and the amount of secondary air input, and the emission of unburned gas (HC) may increase.
[0011]
However, the techniques of the two patent documents cannot positively and accurately supply the secondary air into the combustion chamber. That is, the inflow of the secondary air into the combustion chamber and the backflow of the exhaust gas are further promoted, whereby the unburned gas (HC) in the combustion chamber is actively stirred and reburned, and the exhaust gas is heated by the reburn reaction. The effect (early catalyst activation), unburned gas (HC) reduction effect, and early combustion stabilization cannot be promoted.
[0012]
For this reason, secondary air and exhaust gas are positively flown into the combustion chamber, and the unburned gas (HC) in the combustion chamber is actively stirred and reburned, thereby suppressing the emission of unburned gas (HC). Further, a device capable of stabilizing combustion is expected.
The present invention, based on the above-described problems, further promotes reburning of unburned gas (HC) in a combustion chamber at the time of a cold start of an internal combustion engine, and more accurately discharges unburned gas (HC). It is an object of the present invention to provide an exhaust gas purifying apparatus for an internal combustion engine capable of promoting combustion stabilization.
[0013]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a secondary air supply device for injecting secondary air toward an opening of an exhaust port opened and closed by an exhaust valve of an internal combustion engine, and at least one of an intake valve and an exhaust valve. Valve adjusting means for variably adjusting a valve period or a valve lift amount, operating information detecting means for detecting operating information of the internal combustion engine, and when it is determined from the operating information of the internal combustion engine that the internal combustion engine falls below the cold determination temperature, And a control means for driving the next air supply device and operating the valve adjusting means to increase the amount of overlap between the intake valve and the exhaust valve from that in the normal operation.
[0014]
As described above, at the time of the cold start of the internal combustion engine, the secondary air supply device causes the secondary air to be injected into the combustion chamber through the opening of the exhaust port, and the valve adjustment unit controls the opening timing of at least one of the intake valve or the exhaust valve, The valve opening period or the valve lift amount is variably adjusted to increase the overlap amount from that at the time of steady operation, whereby the exhaust gas is returned by the intake negative pressure after the intake valve is opened and the secondary air combustion chamber during the overlap. Utilizing the synergistic effect with the injection into the combustion chamber, more secondary air and exhaust gas flow into the combustion chamber, and the unburned gas in the combustion chamber is agitated with the secondary air and backflow exhaust gas to promote reburn. Further, it is possible to stabilize the combustion by raising the temperature of the exhaust gas at an early stage, and to reduce the unburned gas remaining in the exhaust gas. Further, by increasing the amount of overlap, the back-flow exhaust gas reaches the intake port, and the wall surface of the intake port is heated, so that atomization of the fuel deposited on the wall surface can be promoted.
[0015]
According to a second aspect of the present invention, in the exhaust gas purifying apparatus for an internal combustion engine according to the first aspect, the valve adjuster variably adjusts a valve opening period or a valve lift of the intake valve, and an exhaust valve. And at least one of exhaust valve variable adjusting means for variably adjusting the valve opening period or the valve lift amount.
[0016]
As described above, at least one of the intake valve variable adjusting means and the exhaust valve variable adjusting means variably adjusts the valve opening period or the valve lift amount of at least one of the intake valve and the exhaust valve to increase the overlap amount from that in the normal operation. Thereby, the secondary air and the exhaust gas are increased by utilizing the synergistic effect of the exhaust retraction effect by the intake negative pressure after the intake valve is opened and the injection of the secondary air into the combustion chamber during the overlap. The fuel is allowed to flow into the combustion chamber, and the unburned gas in the combustion chamber is agitated with the secondary air and the backflow exhaust gas to promote recombustion. Combustion gas can be reduced. Further, by increasing the amount of overlap, the back-flow exhaust gas reaches the intake port, and the wall surface of the intake port is heated, so that atomization of the fuel deposited on the wall surface can be promoted.
[0017]
According to a third aspect of the present invention, in the exhaust gas purifying apparatus for an internal combustion engine according to the first aspect, the valve adjusting means variably adjusts an opening timing, a valve opening period, or a valve lift of the intake valve. In addition, at least one of exhaust valve variable adjusting means for variably adjusting the valve opening timing, valve opening period, or valve lift of the exhaust valve is provided.
[0018]
As described above, at least one of the intake valve variable adjustment unit and the exhaust valve variable adjustment unit is driven to adjust the opening timing, the opening period, or the valve lift of at least one of the intake valve and the exhaust valve to reduce the overlap amount. This is increased from the time of steady operation, thereby utilizing the synergistic effect of the exhaust withdrawal effect due to the intake negative pressure after the intake valve opens and the injection of the secondary air into the combustion chamber during the overlap, and More exhaust gas flows into the combustion chamber, and the unburned gas in the combustion chamber is agitated with the secondary air and backflow exhaust gas to promote re-combustion. Unburned gas remaining in the gas can be reduced. Further, by increasing the amount of overlap, the back-flow exhaust gas reaches the intake port, and the wall surface of the intake port is heated, so that atomization of the fuel deposited on the wall surface can be promoted.
[0019]
According to a fourth aspect of the present invention, in the exhaust gas purifying apparatus for an internal combustion engine according to the first aspect, the control means increases the amount of overlap between the exhaust valve and the intake valve while supplying the secondary air. After a lapse of time, the overlap amount is reduced in proportion to the elapsed time and returned to a steady amount, and at the time of the return, the secondary air supply device is stopped.
As described above, when a predetermined time has elapsed after the overlap adjustment and the secondary air supply process, the unnecessary overburning after the predetermined time has elapsed in consideration of the fact that the unburned gas in the exhaust gas has entered the reduced operating range. The lap adjustment and the driving of the secondary air supply are stopped, so that useless output loss can be prevented.
[0020]
According to a fifth aspect of the present invention, in the exhaust gas purifying apparatus for an internal combustion engine according to the first aspect, the control means drives the secondary air supply device and increases an amount of overlap between the exhaust valve and the intake valve. When the vehicle starts moving before the predetermined time elapses, the overlap amount is returned to the steady amount at the same time, and the secondary air supply device is stopped.
In this way, if the vehicle starts before the predetermined time elapses after the overlap adjustment and the secondary air supply processing, the overlap amount is returned to the steady amount at the same time, and the secondary air supply device is stopped. Then, after the start, the driving of the overlap adjustment and the secondary air supply is stopped, and the control with emphasis on drivability can be allowed.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an exhaust gas purification apparatus M for an internal combustion engine as an embodiment of the present invention, and an internal combustion engine equipped with the same. The exhaust gas purifying device M is mounted on a four-cycle four-cylinder gasoline engine (hereinafter simply referred to as an engine 1) as an internal combustion engine shown in FIG. 1 to promote re-combustion of exhaust gas in the combustion chamber 2 to improve exhaust gas. It works as planned.
Here, the engine 1 is provided with intake and exhaust valves 4 and 5 that are driven by the rotational force of the crankshaft 3. The intake and exhaust valves 4 and 5 connect the intake port 6 on the intake path Ri and the exhaust port 7 on the exhaust path Re. It communicates intermittently with the combustion chamber 2. Further, a fuel injection valve 8 and a spark plug 10 are mounted on each cylinder.
[0022]
The engine 1 employs a multipoint injection system in which fuel is injected into an intake port 6, and a fuel injection valve 8 of each cylinder is supplied with equal-pressure fuel from a fuel supply system (not shown). The fuel amount control unit A1 described in (1) receives the fuel injection output D (Tinj) having a pulse width corresponding to the fuel injection amount Tinj derived from the air-fuel ratio A / F and other operation information to perform the injection operation.
[0023]
The fuel amount control unit A1 of the engine 1 performs the combustion of the air-fuel mixture while maintaining the stoichiometric air-fuel ratio A / F (15, 0) in the steady operation range, so that the pre-catalyst 11 and the main catalyst 12 of the exhaust passage Re are formed. Keep purification efficiency at a high level. During the warm-up operation, the air-fuel ratio is enriched in expectation of an exhaust gas temperature increasing effect (early catalyst activation) due to the reaction of secondary air and unburned gas (HC) described later.
The ignition plug 10 of the ignition system is connected to an ignition circuit 13. When the ignition circuit 13 receives a signal of an ignition timing IGT from an ignition control unit A2 in the controller 9 as described later, the ignition output Dig is output to the ignition timing IGT. Is emitted to the ignition plug 10 to drive the ignition.
[0024]
The intake passage Ri allows air from the air cleaner 20 to flow into each cylinder in the engine body. The intake passage Ri includes an electronically controlled throttle valve (hereinafter simply referred to as ETV 14) 14, an intake pipe 15, a surge tank 16 downstream thereof, An intake manifold 17 having a branch intake passage ri that branches off from the surge tank and is formed in the cylinder head 18 so as to communicate with each branch intake passage ri, and is formed in the combustion chamber 2 when the intake valve 4 of each cylinder is opened. And an intake port 6 communicating therewith. The ETV 14 is configured to switch to the valve opening when receiving the valve opening output Po from the throttle valve driving unit A3 provided in the controller 9 as described later.
[0025]
A throttle opening sensor 19 is mounted on the rotating shaft of the ETV 14, and a throttle opening θs signal generated from the throttle opening sensor 19 is input to the controller 9. Further, an air flow sensor 22 for detecting an intake air amount Qa is attached to the intake pipe 15, and an intake air amount Qa signal is input to the controller 9.
[0026]
The exhaust passage Re leads the exhaust gas from the combustion chamber 2 of each cylinder from the exhaust port 7 to each branch exhaust passage re in the exhaust manifold 23 when the exhaust valve 5 is opened, and further provides the exhaust gas in the middle of the exhaust pipe 40. The pre-catalyst 11 and the downstream main catalyst 12 are successively guided and flow down to the atmosphere. The front-stage catalyst 11 is formed of a three-way catalyst for purifying CO, HC and NOx, and is particularly formed so as to be activated early with a small capacity and to contribute to the purification of unburned gas (HC) immediately after a cold start. The catalyst 12 is formed of a large-capacity three-way catalyst, and is formed so as to contribute to purification of a large-capacity exhaust gas during a steady operation.
[0027]
An air nozzle 25 of a secondary air supply device 24 is attached to the exhaust port 7 of each cylinder toward the back of the exhaust valve 5. The secondary air supply device 24 includes an air pump 27 driven by an electric motor 26, a drive circuit 28 that variably drives the rotation of the electric motor 26, and an air nozzle 25 connected to the air pump 27. The air pump 27 is driven according to a control signal output from the secondary air control unit Aa in the controller 9 to the drive circuit 28, and blows out secondary air from the air nozzle 25 to the exhaust port 7, so that the exhaust port The main part of the exhaust gas flowing out to the combustion chamber 2 is returned to the combustion chamber 2 to stir the exhaust gas in the combustion chamber 2, thereby scraping out the unburned gas (HC) in the combustion chamber 2, The combustion gas (HC) is reburned by the secondary air.
[0028]
A valve operating system for driving the intake and exhaust valves 4 and 5 is a DOHC type valve operating device 40. The intake and exhaust cam shafts 31 and 32 having the intake and exhaust cams 29 and 30 are connected to the crankshaft 3 via belt rotation transmission means (not shown). Is transmitted and driven to rotate.
As shown in FIG. 2, the valve gear 40 drives the intake valve 4 and the exhaust valve 5 for each cylinder. Here, the suction / discharge cam shafts 31, 32 and the suction / discharge rocker shafts 52, 53 are arranged in parallel with each other on the bearing portion 51 of the cylinder head 18, and the intake / discharge cams 29, 30 are provided on the intake / discharge cam shafts 31, 32.
[0029]
The suction and discharge rocker shafts 52 and 53 are pivotally supported by suction and discharge rocker arms 54 and 55. The intake rocker arm 54 contacts the intake cam 29 via a roller 56 pivotally supported at one end, and the other end contacts the intake valve 4. The exhaust rocker arm 55 contacts the exhaust cam 30 via a roller 57 pivotally supported at one end, and the other end contacts the exhaust valve 5.
[0030]
As shown in FIG. 2, the intake cam shaft 31 includes an intake phase adjustment mechanism 33 that is an intake valve variable adjustment unit that variably adjusts the valve opening timing (valve opening center timing) θIc of the intake cam 29. Similarly, the exhaust cam shaft 32 includes an exhaust phase adjustment mechanism 34 which is an exhaust valve variable adjusting means for variably adjusting the valve opening timing (valve opening center timing) θEc (see FIG. 3) of the exhaust valve 5. These intake and exhaust phase adjustment mechanisms 33 and 34 constitute valve adjustment means.
[0031]
A secondary air control unit Aa, which is a control unit of the secondary air supply device 24, is provided in the controller 9. When it is determined from the operation information of the engine that the engine 1 is lower than the cold determination temperature Tc, the secondary air control unit Aa is controlled. Control is performed to drive the supply device 24.
The controller 9 is provided with an intake / exhaust valve variable adjustment unit Ab which is a control unit of the intake / exhaust phase adjustment mechanisms 33 and 34 which is an intake / exhaust valve variable adjustment unit. If it is determined that the temperature falls below the determination temperature Tc, the valve opening timing (valve opening center timing) of the exhaust valve 5 is set to θEc1 that is shifted from the valve opening timing θEc in the steady operation by a delay amount −Δθa, and the intake valve 4 and the exhaust valve are set. The function of controlling the overlap amount of No. 5 to the overlap amount B1 which is larger than the amount B0 in the normal operation.
[0032]
As shown in FIG. 2, the intake / exhaust phase adjusting mechanisms 33, 34 connect the sprockets 35i, 35e provided at the front end of the exhaust cam shaft 32 and the sprockets and the intake / exhaust cam shafts 31, 32 so as to be relatively rotatable. Phase control actuators 36i and 36e. The sprockets 35i and 35e are connected to the crankshaft 3 via a timing belt (not shown). The phase control actuators 36i and 36e are electromagnetic rotary actuators, and are driven and controlled by respective drive circuits 37i and 37e that receive control signals Sti and Ste from the intake / exhaust valve variable adjustment unit Ab in the controller 9. Thus, the valve opening timings (valve opening center timings) θIc and θEc of the lifts of the intake and exhaust valves 4 and 5 are retarded or advanced. The rotational positions of the intake and exhaust camshafts 31 and 32 under the control of the intake and exhaust phase adjustment mechanisms 33 and 34 are detected by the drive shaft sensors 38i and 38e and output to the controller 9.
[0033]
The controller 1 controls the supply / exhaust system, fuel supply system, and ignition system of the engine 1.
The controller 9 detects the operation information of the engine 1 by the operation information detecting means. As the driving information detecting means, the crank angle sensor 41 indicates the unit crank angle Δθc and the engine speed Ne, the throttle opening sensor 19 indicates the throttle opening θs, the air flow sensor 22 indicates the intake air amount Qa, and the vehicle speed sensor indicates the vehicle speed Vc. The air-fuel ratio sensor 43 inputs the air-fuel ratio A / F, and the water temperature sensor 45 mounted on the cylinder block 44 inputs the water temperature wt of the cooling water to the controller 9.
[0034]
Here, the throttle valve driving unit A3 of the controller 9 obtains the normal valve opening Po or the warm-up valve opening Po according to the accelerator pedal opening θa, the vehicle speed Vc, the coolant temperature wt, and the like. After that, the calculated valve opening output corresponding to the normal or warm-up valve opening Po is output to the ETV 14, and the intake air amount control process is performed.
The fuel amount control unit A1 of the controller 9 obtains a basic fuel injection amount Tb according to the engine speed Ne and the throttle opening θs in a steady state, and calculates a correction value T such as an air-fuel ratio A / F and a water temperature wt. A / F , Twt, and the fuel injection amount Tinj (= Tb + T A / F + Twt). Then, an output signal D corresponding to the calculated fuel injection amount Tinj is output to the fuel injection valve 8 to control the fuel injection amount.
[0035]
Here, during the warm-up operation, when secondary air is supplied, which will be described later, an exhaust gas heating effect (early catalyst activation) due to the reaction between the secondary air and the unburned gas (HC) is expected, and the air-fuel ratio A / Correction value T for F A / F Is the correction value T for rich A / F The fuel injection amount Tinj is calculated by r, and the enriched fuel supply is performed.
The ignition control unit A2 of the controller 9 derives the ignition timing IGT in a steady state from the basic ignition timing IGTb according to the throttle opening θs and the like and the retardation correction value ΔIG according to the operating state. Then, the calculated output signal Dig corresponding to the ignition timing IGT is output to the spark plug 10 to perform the ignition process.
[0036]
Next, a description will be given of the operation of the exhaust gas purification apparatus M for the internal combustion engine shown in FIG.
The controller 9 controls the fuel system, the ignition system, and the intake system of the engine 1 along with a main routine (not shown) at the same time when the main switch is turned on, and performs a cold start control routine during the control.
[0037]
When the first cold start control routine is reached, a start determination process is performed in step s1, and after the start determination, the process proceeds to step s2. In this start determination processing, it is determined whether or not the engine speed Ne within a predetermined time after starter driving has exceeded a start determination speed Nes, for example, 300 rpm, and the routine returns to the main routine before the start, and returns to step s2 after the start is completed. Reach Here, it is determined whether or not the cooling water temperature Tw is lower than the cold state determination temperature Tc1 (for example, 25 ° C.). If the temperature is lower, the process proceeds to step s3. Is stopped, and the process returns to the main routine.
[0038]
In step s3, it functions as the secondary air control unit Aa. Here, the temperature is equal to or lower than the cold determination temperature Tc1, and a steady-state rotation signal is output to the drive circuit of the secondary air supply device 24. And the air pump 27 is driven at the steady blow-off pressure Pn1.
As a result, secondary air having a steady blowing pressure Pn1 is blown out from the air nozzle 25 to the exhaust port 7, and exhaust gas flowing from the combustion chamber 2 to the exhaust port 7 in the exhaust stroke flows back to the combustion chamber 2.
[0039]
When the process reaches step s4 from step s3, it functions as the intake / exhaust valve variable adjustment unit Ab here. Here, the sprocket 35i and the suction camshaft 31 are held at the reference valve opening timing (valve opening center timing) θIc by the phase control actuator 36 of the intake phase adjusting mechanism 33. On the other hand, the phase control actuator 36e of the exhaust phase adjustment mechanism 34 switches and holds the sprocket 35e at θEc1 which is shifted from the valve opening timing θEc at the time of steady operation by a delay amount −Δθa.
[0040]
As a result, as shown in FIG. 3, the intake valve 4 (indicated as IN in FIG. 3) at the reference valve opening timing (valve opening center timing) θIn is driven at a valve opening timing θEc1 shifted by a retard amount −Δθa. The exhaust valve 5 (shown as EX in FIG. 3) is driven so as to maintain the overlap amount B1.
[0041]
At this time, during the operation period in the overlap increasing mode U1 with the overlap amount B1 increased from that in the steady operation, the exhaust withdrawal effect due to the intake negative pressure after the intake valve 4 is opened, and the secondary air combustion chamber 2 Due to the synergistic effect with the injection into the combustion chamber, more secondary air and backflow exhaust gas are taken into the combustion chamber during the overlap, and the unburned gas in the combustion chamber is agitated with the secondary air and backflow exhaust gas. (HC) is raked out and stirred, and the unburned gas (HC) is reburned by the secondary air and the backflow exhaust gas, so that the discharged unburned gas (HC) can be reduced as much as possible. Further, by increasing the overlap amount B1, the backflow exhaust gas reaches the intake port 6, and the wall surface of the intake port is heated, so that atomization of the fuel deposited on the wall surface can be promoted.
[0042]
When step s5 is reached from step s4, the count timer TIM1 for a predetermined elapsed time to is driven here, and in step s6, the process returns to the main routine before the lapse, and proceeds to step s7 when the lapse, and the secondary air Stop processing and stop the driving of the intake / exhaust phase adjustment mechanisms 34, 34 in the overlap increasing mode U1, and return to the steady mode (drive the intake / exhaust valves 4, 5 at the reference valve opening timing θIn, θEn) U0. And returns to the main routine.
[0043]
As described above, in the exhaust gas purifying apparatus M of the internal combustion engine in FIG. 1, at the time of the engine cold start, the intake air after the intake valve 4 is opened during the operation period in the overlap increasing mode U1 at the cold state determination temperature Tc1 or less. Due to the synergistic effect of the exhaust withdrawal effect due to the negative pressure and the injection of the secondary air into the combustion chamber 2, more secondary air can be taken into the combustion chamber during the overlap, and at the time of the exhaust stroke of the combustion chamber 2 The unburned gas that is about to be discharged is sufficiently agitated with the secondary air and the backflow exhaust gas and reburned, so that the unburned gas remaining in the exhaust gas can be reduced. Further, by increasing the overlap amount B1, the backflow exhaust gas reaches the intake port 6, and the wall surface of the intake port is heated, so that atomization of the fuel deposited on the wall surface can be promoted.
[0044]
In the above description, in the first cold start control routine, in step s2, it is determined whether or not the cooling water temperature Tw is lower than the cold determination temperature Tc1 (for example, 25 ° C.). However, a second cold start control routine as shown in FIG. 5 may be executed instead. Here, in the second cold start control routine, processes performed in the same manner as the processes in the first cold start control routine are denoted by the same step numbers, and redundant description will be omitted.
[0045]
When the second cold start control routine is reached, a start determination process is performed in step s1, and in step s2, it is determined whether or not the cooling water temperature Tw is lower than the cold determination temperature Tc1, and if it is lower, the process proceeds to step s10. Sometimes, the process proceeds to step s7, and as described later, each control is stopped, and the process returns to the main routine. In step s10, it is determined whether or not the cooling water temperature Tw is lower than a cold determining temperature (for example, 0 ° C.) lower than the cold determining temperature Tc1, and if No, the process proceeds to step s3, and if Yes, the process proceeds to step s11.
[0046]
In step s3, a steady rotation signal is output to the drive circuit of the secondary air supply device 24, the air pump 27 is driven at the steady blowing pressure Pn1, and secondary air of the steady blowing pressure Pn1 is blown from the air nozzle 25 to the exhaust port 7, The exhaust gas in the combustion chamber 2 is stirred, and the unburned gas (HC) in the exhaust gas is reburned.
[0047]
When step s4 is reached, the intake / exhaust valve variable adjustment unit Ab is set, the reference valve opening timing θIn is held by the phase control actuator 36i of the intake phase adjustment mechanism 33, and during the steady operation by the phase control actuator 36e of the exhaust phase adjustment mechanism 34. In this case, the exhaust valve 5 is driven in the overlap increasing mode U1 as shown in FIG.
[0048]
During the operation period in the overlap increasing mode U1, the secondary air is further reduced by the synergistic effect of the exhaust withdrawal effect due to the intake negative pressure after the intake valve 4 is opened and the injection of the secondary air into the combustion chamber 2. A lot of gas is taken into the combustion chamber, and the unburned gas is stirred with the secondary air, the unburned gas (HC) is scraped out, the unburned gas (HC) in the exhaust gas is reburned, and the discharged unburned gas (HC) is reduced as much as possible. Can be reduced.
[0049]
When step s5 is reached, the count timer TIM1 is driven, and in step s6, the elapse of t0 is waited, and the process proceeds to step s7 to stop the secondary air blowing stop processing, stop the overlap increasing mode U1, and return to the steady mode Uo. And return to the main routine.
In step s10, it is determined that the cooling water temperature Tw is lower than the cold determination temperature (for example, 0 ° C.) Tc2, and the process reaches step s11.
[0050]
Here, a high-pressure rotation signal is output to the drive circuit 28 of the secondary air supply device 24 in order to suppress combustion instability by lowering the temperature below the cold determination temperature (for example, 0 ° C.) Tc2, and the drive circuit 28 26 is driven at a high rotation speed, and the air pump 27 is driven at a high blowing pressure. Thereafter, the process sequentially proceeds to steps s4 to s7.
[0051]
Also in this case, as shown in FIG. 3, in the overlap increasing mode U <b> 1, a synergistic effect of the exhaust pullback effect due to the intake negative pressure after the intake valve 4 is opened and the injection of the secondary air into the combustion chamber 2 is provided. The function of agitating the unburned gas with the secondary air and the backflow exhaust gas to increase the function of scraping out the unburned gas (HC) is increased, and the unburned gas (HC) in the exhaust gas is reburned and the discharged unburned gas (HC) is removed. It can be reduced as much as possible, and the combustion stability at extremely low temperatures can be secured. Further, by increasing the overlap amount B1, the backflow exhaust gas reaches the intake port 6, and the wall surface of the intake port is heated, so that atomization of the fuel deposited on the wall surface can be promoted.
[0052]
In the above description, in step s6 of the first and second cold start control routines, at the time when the predetermined elapsed time to elapses, the secondary air blowing stop processing and the valve opening period Veo / lift variable adjustment means The valve opening period Veo is returned to the steady-state valve opening mode. However, if the cooling water Tw becomes equal to or higher than the cooling state determination temperature Tc1 before the elapse of the predetermined elapsed time to, the process proceeds to step s7 at that time, and each control is performed. Is stopped.
[0053]
In the above description, in step s10 of the second cold start control routine, the air pump 27 is driven at the steady blowing pressure Pn1 or the high blowing pressure Pn2 depending on whether the temperature sequentially falls below the cold determination temperature Tc2. Alternatively, as shown in FIG. 6, the processing shown in steps s3 ′ and s11 ′ may be performed.
[0054]
Here, if it is determined that the cooling water temperature Tw is a relatively gentle low temperature exceeding the cold determination temperature Tc2, the process proceeds to step s3 ′, where the air pump 27 blows out the predetermined elapsed time to according to the count value tn of the count timer TIM1. The pressure Pev is calculated from the blow-off pressure-elapsed time map mp (see FIG. 7), the electric motor 26 is driven with a drive output capable of securing the blow-off pressure Pev, and the blow-off pressure of the air pump 27 is adjusted. In this blow-off pressure-elapsed time map mp, the blow-out pressure PevL at the initial elapsed time e1 is set to a high level to stabilize combustion, and the degree of agitation of the unburned gas (HC) and the secondary air in the combustion chamber 2 is set. Enhance. In the later period e2, the rotation level of the electric motor 26, that is, the degree of agitation, is gradually reduced as time elapses, and unnecessary energy loss of the electric motor 26 as time elapses is eliminated. Note that when the temperature reaches the step s11 ′ from the step s10 at the temperature equal to or lower than the cold determination temperature Tc2, the control is performed in the same manner as in the step s3 ′. However, the blowing pressure PevH in the blowing pressure-elapsed time map mp is set to a higher level. As a result, wasteful increase in energy loss according to the passage of time is also eliminated.
[0055]
In the above description, in step s4 of the first and second cold start control routines, the intake / exhaust valve variable adjustment unit Ab is used, and the phase control actuator 36e of the exhaust phase adjustment mechanism 34 determines the valve opening timing θEc during steady operation. The exhaust valve 5 was switched to θEc1 shifted by the retard amount -Δθa, and the exhaust valve 5 was driven in the overlap increasing mode U1, as shown in FIG. On the other hand, as shown in FIGS. 8A and 8B, the intake / exhaust valve variable adjustment unit Ab is advanced by the phase control actuator 36i of the intake phase adjustment mechanism 33 from the valve opening timing θIc at the time of steady operation. The intake valve 4 (indicated as IN in FIG. 8B) may be switched to θIc2 shifted by the amount + Δθa, and the intake valve 4 may be driven in the overlap increasing mode U1.
[0056]
Further, as shown in FIGS. 9 (a) and 9 (b), the intake / exhaust valve variable adjustment unit Ab is used, and the phase control actuators 36i, 36e of the intake / exhaust phase adjustment mechanisms 34, 34 make the valve opening timing θIc at the time of steady operation. The intake valve 4 is switched to θIc3 and θEc3, which are shifted from θEc by the amount of advance angle + Δθa and the amount of retardation by −Δθa, and the intake and exhaust valves 4 and 5 (denoted as IN and EX in FIG. 9B) in the overlap increasing mode U1. It may be driven. In these cases, the same operation and effect as those of the apparatus shown in FIG.
[0057]
In the exhaust gas purifying apparatus M for an internal combustion engine shown in FIG. 1, the intake and exhaust cams 29 and 30 are each a single valve operating device 40. Instead, two intake and exhaust cams are provided as shown in FIG. An exhaust gas purification device Ma (which will be described using the description of the exhaust gas purification device M in FIG. 1 in the same manner) may be configured using the cam two-stage switching valve operating device 60.
Exhaust gas purification device Ma here has components similar to those of exhaust gas purification device M of the internal combustion engine in FIG. 1 except for cam two-stage switching valve operating device 60. Here, the same reference numerals are used for the same members. The description is omitted here.
[0058]
In the cam two-stage switching valve operating device 60, cam shafts 31, 32 and suction / discharge rocker shafts 61, 62 are arranged in parallel in a bearing 51 of a cylinder head 15, and intake cams 29 a, 29 b and exhaust gas are provided on the cam shafts 31, 32. Cams 30a and 30b are provided, respectively. An intake rocker arm 641 is integrally connected to the shaft portion 611 of the intake rocker shaft 61, and the intake rocker arm 641 drives the intake valve 4 at a tip end thereof.
[0059]
A boss portion 631 of the large arm 63 is pivotally supported on a shaft portion 611 of the intake rocker shaft 61, and a small arm 642 is integrally attached next to the boss portion 631. The swing end of the large arm 63 contacts the large intake cam 29a via the roller 65, and the swing end of the small arm 642 contacts the small intake cam 29b via the roller 66.
A switching pin 73 is provided in the shaft portion 611 facing the boss portion 631 of the large arm 63 so as to protrude therefrom and is hydraulically driven by pressure oil from the oil passage 72.
[0060]
An exhaust rocker arm 681 is integrally connected to a shaft portion 621 of the exhaust rocker shaft 62, and the exhaust rocker arm 681 drives the exhaust valve 5 at its tip. The exhaust rocker shaft 62 has a shaft portion 621 on which a boss portion 671 of a large arm 67 is pivotally supported, and a small arm 682 is integrally attached next to the boss portion 671. The swing end of the large arm 67 contacts the large exhaust cam 30a via the roller 69, and the swing end of the small arm 682 contacts the small exhaust cam 30b via the roller 71.
A switching pin 75 is provided in the shaft portion 621 facing the boss portion 671 of the large arm 67 so as to protrude therefrom and is hydraulically driven by pressure oil from an oil passage 74.
[0061]
Each of the oil passages 72, 74 communicates with an oil pump 76 and an oil pan 77 via control oil passages 72a, 74a continuous with the cylinder head 18 side. The control oil passages 72a and 74a are provided with solenoid valves 78 and 79, which are switching valves, respectively. The solenoid valves are driven and controlled by the controller 9a to switch the switching pins 73 and 75, that is, the large and small intake cams. , 29a, 29b and the large and small exhaust cams 30a, 30b are switched. Here, with the solenoid valves 78 and 79 turned off and the switching pins 73 and 75 in a non-projecting state, the large arms 63 and 67 idle and the small cams 29b and 30b and the small arms 642 and 682 operate. As indicated by a broken line in FIG. 11, the intake and exhaust valves 4, 5 (denoted as IN and EX in FIG. 11) are driven in the steady mode U0. On the other hand, when the solenoid valves 78, 79 are turned on, the switching pins 73, 75 protrude and operate, and the large arms 63, 67 are driven by the large intake and large exhaust cams 29a, 30a, and as shown by the solid line in FIG. The valves 4 and 5 are driven in the overlap increasing mode Ua1.
[0062]
The rollers 66 and 68 have the same radius, and the large intake cam 29a, the large exhaust cam 30a and the small intake cam 29b, and the small exhaust cam 30b are formed to have the same radius except the protruding portion.
In such a cam two-stage switching valve operating device 60, as shown in FIG. 11, when the switching pins 73 and 75 retreat, the intake and exhaust valves 4 and 5 are driven in the steady mode U0 by the small intake and small exhaust cams 29b and 30b. When the switching pins 73 and 75 protrude, the intake and exhaust valves 4 and 5 are driven in the overlap increasing mode Ua1 by the large intake and large exhaust cams 29a and 30a to promote agitation of the unburned gas and the secondary air to stabilize combustion. It is possible to ensure the performance and improve the exhaust gas.
[0063]
The exhaust gas purification device Ma of the internal combustion engine is controlled by the controller 9a. Since the controller 9a has the same control as that of the controller 9 except the third cold start control routine shown in FIG. 12, the duplicate description is omitted here.
When the third cold start control routine shown in FIG. 12 is reached, start determination processing is performed in step s1, and in step s2, it is determined whether or not the cooling water temperature Tw is lower than the cold determination temperature Tc1, and if lower, the process proceeds to step s3. At the time of starting after warm-up, the process proceeds to step s7 on the No side, each control is stopped, and the process returns to the main routine. In step s3, a steady rotation signal is output to the drive circuit of the secondary air supply device 24, the air pump 27 is driven at the steady blowing pressure Pn1, and secondary air of the steady blowing pressure Pn1 is blown from the air nozzle 25 to the exhaust port 7, The exhaust gas in the combustion chamber 2 is stirred, and the unburned gas (HC) in the exhaust gas is reburned.
[0064]
When step s4 is reached, the intake / exhaust valve variable adjustment section Ab 'is set, and the reference valve opening timings θIc, θEc are held by the phase control actuators 35i, 35e of the intake / exhaust phase adjustment mechanisms 34, 34.
Further, the cam two-stage switching valve operating device 60 is driven and controlled, that is, the switching pins 73 and 75 are protruded and actuated when the solenoid valves 78 and 79 are turned on, and the large arms 63 and 67 are operated with large intake and large exhaust cams 29a and 30a. And the intake and exhaust valves 4 and 5 are driven in the overlap increasing mode Ua1 (see FIG. 11).
[0065]
During the operation period in the overlap increasing mode Ua1, the secondary air is injected, and the secondary air is burned more due to a synergistic effect with the exhaust return by the intake negative pressure after the intake valve 4 is opened. The unburned gas is taken into the room, the unburned gas is stirred with the secondary air and the backflow exhaust gas, the unburned gas (HC) is scraped out, the unburned gas (HC) in the exhaust gas is reburned, and the discharged unburned gas (HC) is discharged. Can be reduced as much as possible. Further, by increasing the overlap amount B1, the backflow exhaust gas reaches the intake port 6, and the wall surface of the intake port is heated, so that atomization of the fuel deposited on the wall surface can be promoted.
[0066]
When the count reaches step s5, the count timer TIM1 is driven, and in step s6, the elapse of t0 is waited. Then, the process proceeds to step s7 to stop the secondary air blowing stop processing, stop the overlap increasing mode Ua1, and return to the steady mode U0. And return to the main routine.
[0067]
As described above, in the third cold start control routine of the exhaust gas purification device Ma of the internal combustion engine, in step s4, when both the solenoid valves 78 and 79 are turned on, both the switching pins 73 and 75 protrude and operate, and the large arm 63 and 67 was driven by the large intake and large exhaust cams 29a and 30a, and the intake and exhaust valves 4 and 5 were driven in the overlap increasing mode Ua1 (see FIG. 11). However, instead of this, as shown in FIGS. 13A and 13B, in step s4 ', the switching pin 75 projects and operates when the solenoid valve 79 is turned on, and the large arm 67 is driven by the large exhaust cam 30a. Alternatively, the exhaust valve 5 may be driven in the overlap increasing mode Ub1. Conversely, as shown in FIGS. 14 (a) and 14 (b), in step s4 ″, the switching pin 73 protrudes and operates when the solenoid valve 78 is turned on, and the large arm 63 is driven by the large intake cam 29a. May be driven in the overlap increasing mode Uc1. In these cases, the same operation and effect as those of the apparatus of FIG.
[0068]
Further, as shown in FIGS. 15A and 15B, in step s4 ′ ″, the intake / exhaust valve variable adjustment unit Ab ′ is used, and the phase control actuators 35i, 35e of the intake / exhaust phase adjustment mechanisms 33, 34 are connected. The steady-state valve-opening timings θIc and θEc are switched to the valve-opening timings θIc4 and θEc4 by adding the advance amount + Δθa and the retard amount −Δθa. In addition, when both solenoid valves 78 and 79 are turned on, both switching pins 73 and 75 protrude and operate, and large arms 63 and 67 are driven by large intake and large exhaust cams 29a and 30a. As a result, the intake and exhaust valves 4, 5 may be driven in the overlap increasing mode Ud1 of the overlap B1. Thus, in addition to the cam two-stage switching valve operating device 60, the intake phase adjusting mechanism 33 functions as intake valve variable adjusting means for variably adjusting the opening timing, the opening period, or the valve lift of the intake valve 4, and the exhaust phase The adjusting mechanism 34 functions as an exhaust valve variable adjusting unit that variably adjusts the valve opening timing, the valve opening period, or the valve lift of the exhaust valve. In this case, the same operation and effect as those of the apparatus shown in FIG.
[0069]
In the above description, the configuration in which the intake / exhaust phase adjusting mechanisms 33 and 34 are added to the cam two-stage switching valve operating device 60 as the intake valve variable adjusting unit and the exhaust valve variable adjusting unit is shown. Instead of the valve device 60, a lift / operating angle variable mechanism disclosed in JP-A-2002-256905 may be used to variably adjust at least one of the valve opening period and the valve lift amount. Also in this case, the same operation and effect as those of the exhaust gas purifying apparatus Ma using the cam two-stage switching valve train 60 of FIG. 10 can be obtained.
[0070]
【The invention's effect】
As described above, the present invention utilizes secondary air and secondary air by utilizing the synergistic effect of the exhaust retraction action by the negative intake pressure after the intake valve is opened and the injection of the secondary air into the combustion chamber during the overlap. More exhaust gas is allowed to flow into the combustion chamber, and the unburned gas in the combustion chamber is agitated with the secondary air and the backflow exhaust gas to promote re-combustion. It is possible to reduce unburned gas remaining therein. Further, by increasing the amount of overlap, the back-flow exhaust gas reaches the intake port, and the wall surface of the intake port is heated, so that atomization of the fuel deposited on the wall surface can be promoted.
[0071]
According to a second aspect of the present invention, at least one of the intake valve variable adjusting means and the exhaust valve variable adjusting means variably adjusts the valve opening amount or the valve lift amount of at least one of the intake valve and the exhaust valve to adjust the overlap amount during the steady operation. This increases the secondary air and exhaust gas by utilizing the synergistic effect of the exhaust retraction effect by the intake negative pressure after the intake valve opens and the secondary air blowing in the reverse flow direction during the overlap. More gas flows into the combustion chamber, and the unburned gas in the combustion chamber is agitated with the secondary air and the backflow exhaust gas to promote reburning, stabilizing combustion by raising the temperature of the exhaust gas early, and remaining in the exhaust gas. Unburned gas generated can be reduced. Further, by increasing the amount of overlap, the back-flow exhaust gas reaches the intake port, and the wall surface of the intake port is heated, so that atomization of the fuel deposited on the wall surface can be promoted.
[0072]
According to a third aspect of the present invention, at least one of the intake valve variable adjustment means and the exhaust valve variable adjustment means is driven to adjust at least one of the intake valve and the exhaust valve, the valve opening period, and the valve lift amount to adjust the valve opening amount. The amount of lap is increased from that in the steady operation, thereby utilizing the synergistic effect of the exhaust retraction effect by the intake negative pressure after the intake valve is opened and the secondary air blowing in the reverse flow direction during the overlap. Allow more secondary air and exhaust gas to flow into the combustion chamber, stir unburned gas in the combustion chamber with secondary air and backflow exhaust gas to promote reburning, and achieve early combustion stabilization by raising exhaust gas temperature. In addition, unburned gas remaining in the exhaust gas can be reduced. Further, by increasing the amount of overlap, the back-flow exhaust gas reaches the intake port, and the wall surface of the intake port is heated, so that atomization of the fuel deposited on the wall surface can be promoted.
[0073]
According to a fourth aspect of the present invention, considering that the unburned gas in the exhaust gas has entered a reduced operating range when a predetermined time has elapsed after the overlap adjustment and the secondary air supply processing, the predetermined time has elapsed. Unnecessary overlap adjustment and driving of the secondary air supply are stopped, and unnecessary output loss can be prevented.
[0074]
According to a fifth aspect of the present invention, when the vehicle starts before the predetermined time elapses after the overlap adjustment and the secondary air supply processing, the overlap amount is returned to the steady amount at the same time, and the secondary air supply is performed. The apparatus is stopped, and after starting, the overlap adjustment and the driving of the secondary air supply are stopped, so that control emphasizing drivability can be permitted.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an engine equipped with an exhaust gas purification device for an internal combustion engine as one embodiment of the present invention.
FIG. 2 is a plan view of a main part of a valve train in the exhaust gas purifying apparatus of the internal combustion engine of FIG. 1;
3 is an explanatory diagram of a valve opening mode of an intake / exhaust valve of the exhaust gas purifying apparatus for an internal combustion engine of FIG.
FIG. 4 is a flowchart of a first cold start control routine performed by the exhaust gas control apparatus of the internal combustion engine of FIG. 1;
FIG. 5 is a flowchart of a second cold start control routine performed by the exhaust gas purification apparatus for an internal combustion engine of FIG. 1;
FIG. 6 is another modified example of the second cold start control routine performed by the exhaust gas control apparatus of the internal combustion engine of FIG. 1;
FIG. 7 is a characteristic diagram of an outlet pressure-elapsed time map mp used in a second modification of the cold start control routine performed by the exhaust gas purification apparatus of the internal combustion engine of FIG. 1;
8 shows another modification of the second cold start control routine performed by the exhaust gas purification apparatus for an internal combustion engine shown in FIG. 1, in which (a) describes step 4 'and (b) describes the valve opening mode of the intake and exhaust valves. The figure is shown.
9 shows another modified example of the second cold start control routine performed by the exhaust gas control apparatus of the internal combustion engine shown in FIG. 1, wherein FIG. 9 (a) shows step 4 ″ and FIG. 9 (b) shows the valve opening mode of the intake and exhaust valves. The figure is shown.
FIG. 10 is a plan view of a main part of a valve train used in an exhaust gas purification apparatus for an internal combustion engine as another embodiment of the present invention.
FIG. 11 is an explanatory view of a valve opening mode of an intake / exhaust valve used in an exhaust gas purifying apparatus for an internal combustion engine as another embodiment of the present invention.
FIG. 12 is a flowchart of a third cold start control routine performed by the exhaust gas purification apparatus for an internal combustion engine having the valve train of FIG. 10;
13A and 13B show a modification of the third cold start control routine of FIG. 12, in which FIG. 13A shows step 4 ′ and FIG.
14A and 14B are diagrams illustrating another modified example of the third cold start control routine of FIG. 12, in which FIG. 14A illustrates step 4 ″ and FIG. 14B illustrates a valve opening mode of the intake and exhaust valves.
15A and 15B are diagrams illustrating another modified example of the third cold start control routine of FIG. 12, in which FIG. 15A illustrates step 4 ′ ″ and FIG. 15B illustrates a valve opening mode of the intake and exhaust valves.
FIG. 16 is a schematic diagram of a secondary air supply device for an internal combustion engine.
FIG. 17 is a diagram illustrating the function of a secondary air supply device for an internal combustion engine.
[Explanation of symbols]
1, 1a engine
5 Exhaust valve
7 Exhaust port
9, 9a Controller (control means)
24 Secondary air supply device
40 Valve train
45 Water temperature sensor (driving information detection means)
60 Cam two-stage switching valve train
Aa Secondary air control unit
Ab Exhaust valve variable adjustment unit
B0, B1 Overlap amount
M, Ma Exhaust purification device for internal combustion engine
Ri intake path
Re exhaust path
Tw Cooling water temperature (operating information)
Tc1 Cold state judgment temperature
U1 Overlap increase mode
Pn1 steady blowing pressure

Claims (5)

内燃機関の排気バルブにより開閉される排気ポートの開口に向けて２次エアを噴射する２次エア供給装置と、
吸気バルブ又は排気バルブの少なくとも一方の開弁時期、開弁期間或いは弁リフト量を可変調整するバルブ調整手段と、
内燃機関の運転情報を検出する運転情報検出手段と、
内燃機関の運転情報より内燃機関が冷態判定温度を下回ると判定すると、前記２次エア供給装置を駆動すると共に前記バルブ調整手段を作動して、吸気バルブと排気バルブのオーバーラップ量を定常運転時より増大させる制御手段と、
を備えたことを特徴とする内燃機関の排気浄化装置。A secondary air supply device for injecting secondary air toward an opening of an exhaust port opened and closed by an exhaust valve of the internal combustion engine;
Valve adjustment means for variably adjusting the opening timing of at least one of the intake valve or the exhaust valve, the valve opening period or the valve lift;
Operating information detecting means for detecting operating information of the internal combustion engine,
When it is determined from the operation information of the internal combustion engine that the internal combustion engine is lower than the cold determination temperature, the secondary air supply device is driven and the valve adjusting means is operated to set the overlap amount between the intake valve and the exhaust valve to the steady operation. Control means for increasing over time;
An exhaust gas purification device for an internal combustion engine, comprising: 請求項１記載の内燃機関の排気浄化装置において、
前記バルブ調整手段は、吸気バルブの開弁期間あるいは弁リフト量を可変調整する吸気バルブ可変調整手段、及び、排気バルブの開弁期間あるいは弁リフト量を可変調整する排気バルブ可変調整手段の少なくとも一方を有することを特徴とする内燃機関の排気浄化装置。The exhaust gas purifying apparatus for an internal combustion engine according to claim 1,
The valve adjusting means is at least one of an intake valve variable adjusting means for variably adjusting an opening period or a valve lift of an intake valve, and an exhaust valve variable adjusting means for variably adjusting an opening period or a valve lift of an exhaust valve. An exhaust gas purifying apparatus for an internal combustion engine, comprising: 請求項１記載の内燃機関の排気浄化装置において、
前記バルブ調整手段は、吸気バルブの開弁時期、開弁期間あるいは弁リフト量を可変調整する吸気バルブ可変調整手段、及び、排気バルブの開弁時期、開弁期間あるいは弁リフト量を可変調整する排気バルブ可変調整手段の少なくとも一方を有することを特徴とする内燃機関の排気浄化装置。The exhaust gas purifying apparatus for an internal combustion engine according to claim 1,
The valve adjusting means variably adjusts the opening timing, opening period or valve lift of the intake valve, and variably adjusts the opening timing, opening period or valve lift of the exhaust valve. An exhaust gas purifying apparatus for an internal combustion engine, comprising at least one of variable exhaust valve adjusting means. 請求項１記載の内燃機関の排気浄化装置において、
上記制御手段は、上記２次エア供給装置を駆動すると共に排気バルブと吸気バルブのオーバーラップ量を増大させ、その上で所定時間経過後はオーバーラップ量を経過時間に比例して減少させて定常量に戻し、その戻し時点で上記２次エア供給装置を停止させることを特徴とする内燃機関の排気浄化装置。The exhaust gas purifying apparatus for an internal combustion engine according to claim 1,
The control means drives the secondary air supply device and increases the amount of overlap between the exhaust valve and the intake valve, and after a lapse of a predetermined time, reduces the amount of overlap in proportion to the elapsed time, thereby steadily increasing the amount of overlap. An exhaust purification device for an internal combustion engine, wherein the secondary air supply device is stopped at the time of the return. 請求項１記載の内燃機関の排気浄化装置において、
上記制御手段は、上記２次エア供給装置を駆動すると共に排気バルブと吸気バルブのオーバーラップ量を増大させ、その上で所定時間経過前に車両の発進があると、同時点でオーバーラップ量を定常量に戻し、上記２次エア供給装置を停止させることを特徴とする内燃機関の排気浄化装置。The exhaust gas purifying apparatus for an internal combustion engine according to claim 1,
The control means drives the secondary air supply device and increases the amount of overlap between the exhaust valve and the intake valve. If the vehicle starts before a predetermined time elapses, the amount of overlap is determined at the same time. An exhaust purification device for an internal combustion engine, wherein the exhaust gas is returned to a steady amount and the secondary air supply device is stopped.
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007113469A (en) * 2005-10-19 2007-05-10 Toyota Motor Corp Control device for internal combustion engine
JP2009197635A (en) * 2008-02-20 2009-09-03 Toyota Motor Corp Internal combustion engine
WO2014196267A1 (en) 2013-06-05 2014-12-11 トヨタ自動車株式会社 Internal combustion engine
CN114658516A (en) * 2021-05-24 2022-06-24 长城汽车股份有限公司 System and method for reducing emission of nitrogen oxides

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007113469A (en) * 2005-10-19 2007-05-10 Toyota Motor Corp Control device for internal combustion engine
US7716919B2 (en) 2005-10-19 2010-05-18 Toyota Jidosha Kabushiki Kaisha Control device and control method for internal combustion engine
JP2009197635A (en) * 2008-02-20 2009-09-03 Toyota Motor Corp Internal combustion engine
WO2014196267A1 (en) 2013-06-05 2014-12-11 トヨタ自動車株式会社 Internal combustion engine
US9587597B2 (en) 2013-06-05 2017-03-07 Toyota Jidosha Kabushiki Kaisha Internal combustion engine
CN114658516A (en) * 2021-05-24 2022-06-24 长城汽车股份有限公司 System and method for reducing emission of nitrogen oxides

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