JP3806954B2

JP3806954B2 - Exhaust gas purification device for internal combustion engine

Info

Publication number: JP3806954B2
Application number: JP25598395A
Authority: JP
Inventors: 正夫野口; 等隆信江; 統雄垰; 宣彦藤原
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 1995-10-03
Filing date: 1995-10-03
Publication date: 2006-08-09
Anticipated expiration: 2015-10-03
Also published as: JPH0996211A

Description

【０００１】
【発明の属する技術分野】
本発明はディーゼルエンジン（内燃機関）が排出する排気ガス中に含まれるパティキュレート（微粒子状物質）を捕集するフィルタと、捕集されたパティキュレートを加熱燃焼させて除去しフィルタの捕集性能を回復再生する内燃機関用排ガス浄化装置に関するものである。
【０００２】
【従来の技術】
ディーゼルエンジンは、ガソリンエンジンに比べて燃焼効率が高く、耐久性に優れているという特長がある一方で、大気汚染物質を排出する欠点を有している。ディーゼルエンジンが排出する排気ガスの中には窒素酸化物と共にパティキレート（微粒子状物質）が含まれており、排気ガス規制の強化が進められている。この規制強化に対して燃料噴射時期遅延による燃焼改善や軽油の低硫黄化などの燃料改善の取り組みがなされているが、窒素酸化物の低減とパティキュレートの低減とは技術上背反する関係にあり、現状ではエンジン周りでの窒素酸化物の低減を図り、パティキュレートは排気系で処理することが有望な解決策と考えられている。
【０００３】
パティキュレートは、主にＳＯＦ（ＳｏｌｕｂｌｅＯｒｇａｎｉｃＦｒａｔｉｏｎ）、すす、硫黄化合物の３種類からなり、このパティキュレートを排気系で処理する方法として、ＳＯＦを減少させる酸化触媒方式やフィルタを用いてパティキュレートを捕集する方式が進められている。酸化触媒方式は、すすの低減ができないためフィルタ方式が好ましい。ところが、フィルタ方式は、パティキュレートを捕集し続けるとフィルタは目詰まりを生じて排気ガスの流れが悪くなってエンジン出力の低下あるいはエンジンの停止に至る。これに対して現在では、フィルタの捕集能力を再生させるための技術開発が進められている。フィルタに捕集されたパティキュレートの量があまりに多くなるとエンジンに対しての負荷が増し、最悪の場合、エンジン停止に至るので適当な時期にパティキュレートを除去する必要がある。
【０００４】
フィルタの捕集性能を再生する方法としてフィルタ内でパティキュレートを燃焼除去する方式や高圧空気を供給しフィルタ外にパティキュレートを吹き飛ばしてフィルタ外部でパティキュレートを燃焼除去する方式が提案されている。フイルタ外部で処理する方式は、パティキュレートの除去を完全に行うことが課題であり、再生方式の主流は、フィルタ内で燃焼除去させる方式である。パティキュレートは６００℃程度から燃焼することが知られている。パティキュレートをこの高温度領域に昇温するためのエネルギー加熱手段として、バーナ方式、電気ヒータ方式あるいはマイクロ波方式などが考えられている。
【０００５】
マイクロ波加熱方式によるフィルタ再生装置としては、たとえば図７に示すように、エンジン１０１から排出された排気ガスが第一通路管１０２、フィルタ１０３、連結管１０４、遮断弁１０５を経て排気トップ１０６から、大気へ排出される捕集手段と、一定時間経過後、エンジンを停止し、かつ遮断弁１０５を一時遮断して、フィルタ１０３と遮断弁１０５の間に設けられたマイクロ波加熱部１０７を作動させ、送風手段１０８により空気供給口１０９から空気を送り込みながら、フイルタ１０３内に溜まったすすを燃焼させ、ここで発生した燃焼ガスを第一通路管１０２から分岐された分岐管１１０、開放された排気弁１１１を経て排気トップ１０６へ排出してフィルタ性能を回復する再生手段から構成された逆流型排ガス浄化装置がある。
【０００６】
上記構成において、エンジン１０１から排出された排気ガスにはすす等のパティキュレートが含まれており、これが捕集手段の作用によってフィルタ１０３を通過する間、フィルタ１０３に捕集される。一定時間、捕集過程を踏んだ後、エンジン１０１を一時停止し、かつ遮断弁１０５を遮断して、マイクロ波加熱部１０７を作動させ、空気供給口１０９から空気を送り込みながら、フイルタ１０３内に溜まったすすを加熱燃焼させ、ここで発生した燃焼ガスを第一通路管２から分岐された分岐管１１０、開放された排気弁１１１を経て排気トップ１０６、大気へと排出してフィルタ１０３の性能が回復される。
【０００７】
この後、再び、捕集手段の動作に移り、同様のプロセスが繰り返される。また、他の従来例として、再生時の燃焼ガスを再びフイルタ内に戻し循環させる再循環回路と、外部空気吸い込みバルブと酸素センサーを配設し燃焼ガス循環型排ガス浄化装置（特開平６−３２３１３０号公報）がある。
【０００８】
この装置は、燃焼後のガスを、主として炭酸ガスを再びフイルタへ戻し、外気の酸素濃度に比べて、相対的に酸素濃度を下げ、燃焼時の発熱温度を抑えると同時に、酸素センサの出力に応じて、外気吸い込みバルブを開閉し、フィルタ内を通過する空気量（酸素量）を変え、酸素濃度を下げて燃焼温度を抑制する。
【０００９】
【発明が解決しようとする課題】
しかしながら上記従来の構成では、先ず逆流型排ガス浄化装置においては再生時のフィルタ内に溜まったパティキュレートのうち、多少の加熱ムラに起因して、初期段階では一部のパティキュレートのみが燃焼し始め、次第に燃焼温度が高温度に達する。しかし他方では、まだ同時に燃えない領域や温度が上がり切れないフィルタの領域などが現れ、温度差の大きい温度分布となる。この結果フィルタの熱衝撃が大きくなると共に、フィルタにクラックが発生する場合がある。このため次の捕集時にはパティキュレートがリークし捕集効果がなくなる等の問題が起こり、フィルタの再利用ができない場合があった。またフィルタ内の燃焼温度を下げるため、空気の吸い込み量を小さい方向へ変えようとすると、かなり小さく制御しないと燃焼温度を抑制できないことと、あまり小さく成り過ぎて逆にフイルタ内の流量分布に大きなムラが生じと同時に、完全に燃焼し切れないパティキュレートの残留領域が生じる。この結果、フイルタの再生率（（再生前の捕集量−再生後の残留量）を再生前の捕集量で割った値）が悪くなるという課題があった。また、捕集、再生がくり返されると流量分布の悪さが広がり残留量が益々増加する傾向になる。またマイクロ波加熱手段方式は加熱面の端面に近い程、パティキュレートが燃焼し難いという課題がある。これは端面では放熱が大きく、着火温度まで加熱することが難しく、かつ、やや奥へ入った領域のパティキュレートから燃焼が始まるので、端面の領域のパティキュレートは多少残るという問題がある。この結果、フイルタの再生率が低くなるという課題があった。
【００１０】
また、酸素センサの出力に応じて、外気吸い込みバルブを開閉し、フィルタ内を通過する空気量（酸素量）を変え、燃焼温度を抑制する燃焼ガス循環型排ガス浄化装置（特開平６−３２３１３０号公報）においては、酸素センサの感度の経年変化、応答性に問題があり、一方、その出力に応じて開閉する吸い込みバルブが加わるため、パティキュレートの燃焼速度と循環流量の制御と同時に変化する酸素濃度の応答性に大幅な開きが生じる。この結果、実際の現象に制御が追従しなくなり制御特性にオーバーシュートなどのハンチング現象が現れ、益々、フィルタ内の燃焼温度を適切な範囲に制御することが困難になる課題があった。さらにフィルタには、細い、小さなフィルタ機能を有するセルの集まりからできているため、局部的な燃焼が起こると、局部のセル内のパティキュレートのみが燃焼し、これが進行していくと、この部分の空気抵抗が減少し、他の燃焼仕切れていないパティキュレート領域、所謂空気抵抗の大きい領域を避けて益々この部分に集中して流れるようになる。
【００１１】
この結果、益々局部的な燃焼が活発になり、燃焼温度が益々上昇する。一方の酸素センサの出力に関係する全体の燃焼ガス中の酸素濃度としては平均化されるため結果としては変化がないという情報となり、コントロール回路としては制御動作が行われないという現象が現れる。このため、フィルタ内の温度分布は温度差が大きい状態となり、フィルタに熱衝撃が起り易くなる。この結果フィルタにクラックが発生する場合が予想され、このまま使用すると次の捕集時にはパティキュレートがフィルタからリークし捕集効果がないという問題が起り、フィルタの再利用ができない場合が考えられる。また局部の温度上昇を避けようとして酸素センサの出力に対する制御設定値を変え空気の吸い込み量を抑えようとすると燃焼が進まない領域が逆に増え、益々再生率が悪くなるという問題が発生していた。
【００１２】
また、フィルタ内の局部的な燃焼が進行し、この部分のパティキュレートの燃焼が終了に近づくと空気抵抗が、さらに減少し、通過する空気量も集中し、この部分の流量が増大すると同時に燃焼に使われない空気量の割合も増大する。この結果酸素濃度の増加と共に酸素センサの出力も増大するためコントロール回路には酸素濃度を抑えようと吸い込みバルブを空気供給量を減らす方向に作用する。このため他の領域のセル内には、まだ酸素を必要とするパティキュレートが残っており、未燃焼まま残るという問題があった。また、酸素センサーの耐久性、信頼性、応答性が悪く、これに加えて制御機構が複雑であるため、要素部品の増加も加わってコストも高くなる。したがって、このような従来例の燃焼ガス循環形排ガス浄化装置は十分な効果が期待できない。
【００１３】
本発明は上記課題を解決したもので、パティキュレートの過燃焼防止、局部燃焼による焼却ムラの防止を図りつつ再生率を上げることを第１の目的とし、さらに小型化、信頼性の向上を第２の目的としたものである。
【００１４】
【課題を解決するための手段】
本発明は上記第１の目的を達成するための第１の手段として、内燃機関の第一排気管と排気トップとの間に配設して排気ガス中に含まれるパティキュレートを捕集するフィルタと、前記パティキュレートを加熱させる加熱手段と、送風量の可変機能を有する送風制御手段と、前記送風制御手段の吐出部と前記フィルタと前記送風制御手段の吸入部の間を前記パティキュレートの燃焼反応で生成した燃焼ガス通流用に接続された再循環回路と、前記フィルタと前記送風制御手段の吸入部との間の再循環回路に第一吸気口と負圧応動形の第一逆止弁から成る第一吸気手段を設けた構成としてある。
【００１５】
また上記第１の目的を達成するための第２の手段として内燃機関の第一排気管と排気トップとの間に配設して排気ガス中に含まれるパティキュレートを捕集するフィルタと、前記パティキュレートを加熱させる加熱手段と、送風方向の可逆機能および送風量の可変機能を有する可逆形送風制御手段と、前記可逆形送風制御手段の吐出部と前記フィルタと前記可逆型送風制御手段の吸入部の間を前記パティキュレートの燃焼反応で生成した燃焼ガス通流用に接続された再循環回路と、前記フィルタと前記可逆形送風制御手段との間において前記フィルタに作用する前記加熱手段の作用方向と同一方向に送風させる順流再循環回路に設けた第一吸気口及び負圧応動形の第一逆止弁から成る第一吸気手段と、前記フィルタと前記可逆送風制御手段との間において前記フィルタに作用する前記加熱手段の作用方向と相対方向に送風させる逆流再循環回路に設けた第二吸気口及び負圧応動形の第二逆止弁からなる第二吸気手段を設けて構成としてある。
【００１６】
そしてさらに上記第２の目的を達成するため、可逆型送風制御手段は、入力電圧を制御して前記可逆型送風制御手段の電動機の回転をＯＮ、ＯＦＦまたは回転数を可変制御するコントロール機能と、前記電動機の回転方向を切り替える再生制御機能とを有する運転制御回路を設けた構成している。また、再生初期段階の運転モードを、フィルタに作用する加熱手段の作用方向と可逆型送風制御手段の送風方向を相対して作動する逆流再生運転モードと、前記逆流再生運転モードの運転前後加熱手段の作用方向と前記可逆型送風制御手段の送風方向を一致させて作動する順流再生運転モードとする運転制御回路を設けた構成としてある。
【００１７】
またさらに第２の目的を達成するための手段として、送風制御手段と第一吸気手段は、前記送風制御手段のファンケーシングと吸入部との間に第三吸気口と負圧応動形の第三逆止弁から成る第三吸気手段を設けて一体にした構成としてある。
【００１８】
また第２の目的を達成するための手段として、可逆形送風制御手段と第一吸気手段および第二吸気手段は、送風可逆機能を有する渦流形ファンと、ガスが流入する前記渦流形ファンの吸入部に外気を吸い込む吸気口と、前記吸気口の開度を制御する負圧応動形の逆止弁とを有する吸気手段を内設した構成としてある。
【００１９】
さらに第２の目的の信頼性を向上させるために、送風制御手段の吸入部に微粒子物質の流入を防止するエアーフィルタを設けた構成としてある。
【００２０】
同じく信頼性を向上させるために、送風制御手段の電動機能をブラシレス直流電動機で構成してある。
【００２１】
【発明の実施例の形態】
本発明は上記第１の手段によって、フィルタに捕集されたパティキュレートを燃焼焼却しフィルタを再生する過程において、エンジンを一旦停止し、またはエンジンからの排気ガスを切り替えて流入を遮断し、加熱手段と送風制御手段を作動させ、前記フィルタへ空気を送り込みながら加熱をし、このときに発生する燃焼ガスを再び再循環回路を循環させ、フィルタへ戻すことによって燃焼温度を抑制しながら再生するが、この送風制御手段の回転数を制御し送風量を増やすと再循環回路の吸気口の近傍では負圧が大きくなり、外部から吸い込まれる空気量も増大する。また逆に送風制御手段の送風量を減らすと、これに対応して吸気口での負圧は低くなり外部空気の吸い込み量も減少する。すなわち第一逆止弁の開き度合が自動的に変化する形になるため負圧の大きさに対する吸い込み量は単なる吸気口だけの状態よりも下方向へ大きく変化することになる。このため送風制御手段から吐出される吐出風量の酸素濃度も、低い方へ大きく変化する。したがって、これは流量を下方へ流量制御することによって、フィルタに流入する流束分布を均一化し、かつ過燃焼や局部燃焼の加速を制御する空気量の酸素濃度を下げることができる。
【００２２】
また大きい負圧の領域、即ち逆止弁の開度が大きい領域、即ち送風量の大きい領域では負圧に対する開度の変化は小さく、むしろ開口数、または開口径で、ほぼ規定される領域であるため吸い込み量は相対的に大きくなるが、酸素濃度としての変化量は小さい。この結果循環量を大きく増加させることによって吸い込み空気量も増大するが酸素濃度はあまり変化しない領域で可変できる。したがって、酸素濃度を外気の酸素濃度よりも一定値以下で、かつ低流量時の酸素濃度よりも高目に保持し、急激な温度上昇を抑制しつつ、大量の送風量をフィルタへ送り込むことができ、これによる冷却効果を持たせつつ燃焼温度を上限近傍で保持し燃焼を活性化し促進をはかることができる。
【００２３】
また送風制御手段の送風方向を互いに逆向きに流れるようにした第２の手段のものは、再生の初期段階では、フィルタへ送り込む送風方向を逆方向に流し、所謂フィルタに作用する加熱手段の作用方向と送風制御手段の送風方向を相対して作動させる。したがってややフィルタの奥へ入ったパティキュレートから燃焼が始まっても、送風方向が加熱手段側の端面へ向けて流れているため端面の領域のパティキュレートは、高い燃焼温度のガスの影響を受けて、燃焼を余儀なくされ焼却される。そして再循環回路を経て燃焼ガスがフィルタへ戻ってくるため酸素濃度は急激に低下し燃焼温度は急激に上昇しない。この結果フィルタに対しての熱衝撃は緩和されクラックの発生防止の効果が得られる。
【００２４】
一方、この端面のパティキュレートの燃焼を一定時間進行させた後、順流方向に送風方向を替え、高温の燃焼ガスを順流方向に向きを替えると共に、この順流方向と並行して加熱手段の加熱作用が加わり、さらに上記の再循環流量の制御と第一逆止弁の酸素濃度の可変作用によってパティキュレートの燃焼がより一層進行されることができる。この結果総合的にフィルタ再生率の向上が期待される。
【００２５】
そして第一、第二吸気口とそこに設けた第一、第二逆止弁は前記と同様の作用を果たし、フィルタの急激な燃焼温度の上昇を抑制できる。
【００２６】
また再生初期段階の運転モードを、フィルタに作用する加熱手段の作用方向と送風制御手段の送風方向を相対して作動する逆流再生運転モードとし、かつ前記逆流再生運転モードの運転後前記加熱手段の作用方向と前記送風制御手段の送風方向を一致させて作動する順流再生運転モードとした運転制御回路を設けたもの、または入力電圧を制御して送風制御手段の電動機の回転をＯＮ、ＯＦＦまたは回転数を可変制御するコントロール機能と、前記電動機の回転方向を切り替えて送風方向の可逆機能を備えた運転制御回路を設けたものは、回路性能や信頼性が高く、コンパクトな回路構成が得られる。
また送風制御手段のファンケーシングと吸入部との間に外気を取り込む第三吸気口と第三逆止弁から成る第三吸気手段を一体にしたものは、再循環回路の小形化と直流電動機の高制御性が期待できる。
【００２７】
また送風方向の可逆循環機能を有する渦流形ファンと送風量可変機能を有する回転数可変機能と正逆回転機能有する形の電動機から成る送風制御手段に、外気を吸い込む吸気口と前記吸気口の開度を制御する無動力形の逆止弁とを有する吸気手段を内設したものは、システムがさらに簡単化され、高い信頼性と低コスト化が得られる。
【００２８】
また送風制御手段の吸入部に微粒子物質の流入を防止するエアーフィルタを備えたものは、外気ならびに再循環回路からのゴミや燃焼ガス中の微粒子物質のファン回転部への流入を防止ができる。
【００２９】
また送風制御手段の電動機としてブラシレス形直流電動機を用いたものは、電動機の整流子部内で発生するスパークの問題もなくなる。
【００３０】
以下本発明の第１の実施例を図１を参照して説明する。図１において、１は内燃機関用排気ガス浄化装置を示し、本装置１は、フィルタ３、マイクロ波加熱器等の加熱手段４、連結管５、バルブユニット６、排気トップ７、送風量可変機能を有する送風制御手段８、再循環回路９、第一吸気手段１０、温度検知器１１、運転制御回路１２から構成されている。
【００３１】
またこの実施例における加熱手段（以下マイクロ波加熱手段と称す）４はマグネトロンユニット１３と導波管１４、インレット缶体１５を接続して構成されている。またバルブユニット６は遮断弁１６と排気バルブ１７と、遮断弁１６が閉のときは排気バルブ１７は開、遮断弁１６が開のとき排気バルブ１７は閉の状態になるようにプル・ダウン機能を有するバルブ開閉ユニット１８から構成されている。送風制御手段８は送風量可変機能を有するターボファン１９と、これを駆動するブラシレス直流電動機２０、吸入部２１、吐出部２２から構成されている。温度検知器１１はフィルタ３に作用する前記マイクロ波加熱手段４の作用方向と同じ方向に風を送る、所謂順流送風方式のフィルタ出口の燃焼温度を検出するために第一排気管２に配設されて構成されている。
【００３２】
システムはパティキュレートを捕集過程では第一排気管２、アウトレット缶体２３、フィルタ３、インレット缶体１５、連結管５、バルブユニット６、排気トップ７の順に接続し、エンジンの排気ガスは前記接続順に流れ第一排気管２から流入し排気トップ７を経て大気へ排出されるように構成されている。
【００３３】
さらにパティキュレートがフィルタ３に一定以上捕集されるとフィルタ３の再生を行なうが、これは送風制御手段８の吐出部２２と空気送風管２４、インレット缶体１５、フィルタ３、アウトレット缶体２３、第一排気管２、バイパス管２５、排気バルブ１７、排気トップ７、戻り管２６、冷却熱交換器２７、前記送風制御手段８の吸入部２１へと循環するように接続され、再循環回路９を構成している。さらに排気トップ７と前記送風制御手段８の吸入部２１間の一部に、外気を取り込む第一吸気口２８と負圧応動形の第一逆止弁２９から成る第一吸気手段１０が配設されている。
【００３４】
また運転制御回路１２は、捕集過程から再生過程への移行する制御、またはその逆の制御を行うもので、捕集量に応じて変化するマイクロ波の電磁波強度を検出する捕集センサ３０の出力、運転時間、温度検知器１１の値から制御動作を行なうように構成されている。
【００３５】
上記構成において、まず捕集過程においては、内燃機関であるエンジンから排出された排気ガスはアウトレット缶体２３を経て、フィルタ３から連結管５、バルブ開閉ユニット１８を介して開かれた遮断弁１６、排気バルブ１７の通路を経て排気トップ７から大気へ放出される。このとき排気ガスに含まれるパティキュレートはフィルタ３に捕集される。
【００３６】
また再生過程では、一定量のパティキュレートが捕集されたことを検知した後、運転制御回路１２の作動よって捕集過程から再生過程に切り変わる。
先ず再生過程ではエンジンから第一排気管２へ流入する排気ガスを一旦遮断し（例えば切り替えバルブで排気方向を換えるとか、エンジンを一旦停止する場合を指す）、前記バルブユニット６の遮断弁１６を閉、排気バルブ１７を開の状態に切り替え、マイクロ波加熱手段４と送風制御手段８を作動させる。これにより前記マイクロ波加熱手段４がフィルタ３内のパティキュレートを加熱燃焼させ、同時に送風制御手段８の作動によって空気は空気送風管２４、連結管５、インレット缶体１５を経て、フィルタ３へ送り込まれる。この空気はパティキュレートの燃焼の助成用として消費される。ここで燃焼反応で生成した燃焼ガスはアウトレット缶体２３、バイパス管２５、排気バルブ１７、戻り管２６を経て通流し、冷却熱交換器２７によって冷却されながら前記送風制御手段８の吸入部２１へ戻り、これが再び再循環される。所謂再循環回路９が形成される。
【００３７】
ここで上記排気トップと送風制御手段８の吸入部２１との間に再循環回路の一部（戻り管２６）に外部空気を導入する第一吸気口２８と、負圧応動形の第一逆止弁２９を設けて第一吸気手段１０を構成しているため、送風制御手段８の回転数を制御し送風量を増やすと第一吸気口２８の近傍では負圧が大きくなり、外部から吸い込まれる空気量を増大する。また逆に送風制御手段８の送風量を減らすと、これに対応して第一吸気口２８での負圧が低くなり外部空気の吸い込み量も減少する。すなわち上記構成の本発明では無動力形の逆止弁から成る第一吸気手段１０が配設されているため負圧の大きさに応じて第一逆止弁２９の開き度合が変化する、所謂自動的に開度が変化する形になるため負圧の大きさに対する吸い込み量は単なる吸気口だけの状態よりも第一逆止弁２９は下方向へ大きく変化することになる。特に負圧の低い領域では第一逆止弁２９の開度は小さいため、負圧に対する吸い込み量の変化率は高い領域と言える。このため送風制御手段８から吐出される吐出風量の酸素濃度も、低い方へ大きく変化する。したがって、これは流量を下方へ流量制御することによって、フィルタに流入する流束分布を均一化し、かつ空気量の酸素濃度を下げることができるため過燃焼や局部燃焼の加速を抑制する効果が得られる。
【００３８】
また大きい負圧の領域、即ち第一逆止弁２９の開度が大きい領域、即ち送風量の大きい領域では負圧に対する開度の変化は小さく、むしろ開口数、または開口径で、ほぼ規定される領域であるため吸い込み量は相対的に大きくなるが、酸素濃度としての変化量は小さい。この結果循環量を大きく増加させることによって吸い込み空気量も増大するが酸素濃度はあまり変化しない領域で可変できる。したがって、酸素濃度を外気の酸素濃度よりも一定値以下で、かつ低流量時の酸素濃度よりも高目に保持し、急激な温度上昇を抑制しつつ、大量の送風量をフィルタ３へ送り込むことができ、これによる冷却効果を持たせつつ燃焼温度を上限近傍で保持し燃焼を活性化し促進をはかることができるため再生時間の短縮化とフィルタの保護が期待できる。
【００３９】
なお第一吸気口２８から吸い込んで増加したガス分はフィルタ３から戻ってきた循環流量、所謂燃焼ガスの一部が排気トップ７を介して大気へ流れてバランスされた再循環回路が形成される。所謂、送風制御手段８の送風量に対する吸入側の負圧、第一逆止弁２９の開度、吸い込み量との関係を予め規定しておけば送風制御手段８の吐出風量、即ち循環流量の小さい領域ではより低めの酸素濃度で、そして酸素濃度の大きい変化率で制御が可能となる。一方、循環流量の大きい領域では高めの酸素濃度がほぼ一定で循環流量の制御が可能となり、高い制御性によるフィルタ熱衝撃の防止と再生率の向上、ならびに再生時間の短縮化が期待される。
【００４０】
次に本発明の第２実施例の双方向形排気ガス浄化装置を図２を用いて説明する。図２において、図１に示した構成との相違点は、フィルタ３に流入する送風方向を双方向に可逆的に替えるための可逆形送風制御手段３１と、逆方向への送風循環時に外気から空気を取り込む第二吸気口３２、負圧応動形の第二逆止弁３３から成る第二吸気手段３４と、さらに逆送風時に燃焼温度を検出する第二温度センサ３５を具備している点である。上記可逆形送風制御手段３１は、第一ファン１９と、これを駆動する直流電動機２０からなる送風制御手段８、吸入部２１、吐出部２２、第一開閉弁３６を順流方向に接続した順流再循環回路９ａと、一方の第二ファン３７、直流電動機３８、前記第二ファン３７の第二吸入部４０、第二吐出部３９から成る第二送風制御手段４１と、ガスの流入を防止する第二開閉弁４２を逆流方向に接続された逆流再循環回路９ｂを並列に接続して構成されている。
上記構成において、再生初期段階では、送風制御手段８を停止し、第一開閉弁３６を閉止、ならびに第二送風制御手段４１をＯＮ、第二開閉弁４２を開にすることによって、循環流量は再循環回路９の第一通路管２６、排気弁１７、バイパス管２５、アウトレット缶体２３を経てフィルタ３に流入し、インレット缶体１５、連結管５、第二通路管２４を経て第二開閉弁４２から第二送風制御手段４１に戻り逆流方向に再循環される。一定時間後、前記第二送風制御手段４１をＯＦＦ、第二開閉弁４２を閉止、送風制御手段８をＯＮ、第一開閉弁３６を開にすることによって循環流量は第二通路管２４、連結管５、インレット缶体１５を経て、フィルタ３へ流入し、さらにアウトレット缶体２３、バイパス管２５、排気弁１７、第一通路管２６、冷却熱交換器２７を経て前記送風制御手段８に戻り、順流方向に再循環される。
【００４１】
すなわち、この実施例では、再生の初期段階では、フィルタ３へ送り込む送風方向を逆方向に流し、所謂フィルタに作用する加熱手段４の作用方向と送風制御手段８の送風方向を相対して作動させることによって、ややフィルタの奥へ入ったパティキュレートから燃焼が始まっても、送風方向が加熱手段側の端面へ向けて流れているため端面の領域のパティキュレートは、高い燃焼温度のガスの影響を受けて、燃焼を余儀なくされ焼却されるという利点がある。さらに再循環回路を経て燃焼ガスがフィルタ３へ戻ってくるため酸素濃度は急激に低下するため燃焼温度は急激に上昇しない。この結果フィルタ３に対しての熱衝撃は緩和されクラックの発生防止の効果が得られる。この端面のパティキュレートの燃焼を一定時間進行させた後、順流方向に送風方向を替え、高温の燃焼ガスを順流方向に向きを替えると共に、この順流方向と並行してマイクロ波加熱手段４の加熱作用が加わり、さらに上記の再循環流量の制御と第一逆止弁２９の酸素濃度の可変作用によってパティキュレートの燃焼がより一層進行されることができる。この結果総合的にフィルタ再生率の向上が期待される。
【００４２】
この再生初期段階の再生動作では、即ち送風制御手段８によって逆方向へ送風するのでマイクロ波加熱手段４によって、フィルタ３の端面からやや奥へ入った領域のパティキュレートから燃焼が始まっても、送風方向が加熱手段側の端面へ向けて流れているため端面の領域のパティキュレートは、高い燃焼温度のガスの影響を受けて、燃焼するが、その燃焼ガスが再循環回路を経てフィルタ３へ戻ってくるため急速に酸素量は減少する。これは可逆送風制御手段３１の逆方向送風作用によって吸入部は吐出側に切り替わった状態となるため第一吸気手段１０の第一逆止弁２９の閉止動作の働きで第一吸気口２８から空気の取り込みがないためである。すなわち送風制御手段や再循環回路内に残留していた初期段階の空気量で賄われているだけである。これだけでは、燃焼温度の急激な上昇抑制としては効果があるが、フィルタ端面領域のパティキュレートを燃焼させるに必要な酸素量は不足し、燃焼の進行促進としての酸素量は十分とは言い難い。そこで上記構成に加えて、前記フィルタ３と前記可逆送風制御手段３１の吐出系統の再循環回路に第二吸気口３２と第二逆止弁３３を備えた第二吸気手段３４を配設してあるのである。これによって、再生動作の初段階で送風制御手段８の逆方向へ送風された場合でも、前記第二吸気口３２から外気を取り込み、フィルタ端面のパティキュレートの燃焼に必要な酸素量は補充できると同時に低酸素濃度の混合ガスであるため急激な燃焼温度の上昇も抑制できる。この結果、第二吸気手段３４の作用によって、さらに信頼性の高い、高再生率が得られる。
【００４３】
次に図３、図４を用いて送風制御手段の他の実施例を説明する。図３はターボ形送風制御手段の全体構成を、図４はファンケーシングに配設された第三吸気手段の要部拡大図を示し、これは図１に示した本発明の排ガス浄化装置の送風制御手段８と第一吸気手段１０を一体にまとめた送風制御手段として構成されている。図３、図４において、戻ってきたガスの吸込通路５０、第三吸入部５１、ファンケーシング５２、ファンボディ５３、これらに囲まれて配設されたターボ形回転翼５４、吐出部５５と前記回転翼５４を駆動する直流電動機５６からなり、ターボ形送風制御手段５７を構成している。そして前記ターボ形送風制御手段５７は、前記ファンケーシング５２と第三吸入部５１との間の前記ファンケーシング５２に、図４に示すように外気を取り込む第三吸気口５８、この第三吸気口５８から逆流しないようにシート状のリード弁形第三逆止弁５９、ここから吸い込んだ空気を前記吸入部５１に導くために吸入部近傍の前記ファンケーシング５２に設けられた空気導入口６０から成る第三吸気手段６１を備えて構成されている。
【００４４】
上記構成において、直流電動機５６によってターボ形回転翼５４が回転すると、戻ってきた燃焼ガスが吸込通路５０を経て、吸入部５１に入るが、このとき、吸入部５１の領域は負圧の状態になるため空気導入口６０を介して第三逆止弁５９が開き、第三吸気口５８から空気が取り込まれ、燃焼ガスと混合される。ここで混合された低い酸素濃度のガスは吐出部５５からフィルタ３へ送り込まれることになる。このような送風方式は図１に示した本発明の排ガス浄化装置の送風制御手段８と第一吸気手段１０を一体にまとめた構成であると同時に、図２に示した本発明の排ガス浄化装置の可逆形送風制御手段３１において、送風制御手段８と第一吸気手段１０を一体にまとめたものと同様の構成であり、また送風制御手段４１と第二吸気手段３４を一体にまとめた物と同様の構成であり、かつ同様の作用が得られる。したがって、この本発明のターボ形送風制御手段５７は図１、または図２に示した排ガス浄化装置の送風制御手段と吸気手段を本発明の送風制御手段に置き換えて利用できる。
【００４５】
次に可逆形送風制御手段の他の例を図５、図６を用いて説明する。この可逆形送風制御手段７８は、可逆機能を有する渦流形ファンと、吸入部と、吐出部と、前記吐出部に設けた逆止弁付き吸気手段と、前記吸入部または吐出部にゴミ、排気ガス中の微粒子のファン内部への流入を防止するフィルタを一体に内設して構成した物である。図５、図６において、渦流形ファン６４は、ファンボディＡ６５、ファンボディＢ６６、これに囲まれて回転する渦流形回転翼６７、ファンカバー６８、吸入部６９、吐出部７０と前記渦流形回転翼６７に回転動力を与える直流電動機７１から構成されており、この可逆形渦流形ファン６４と、順流時にガスが流入する前記吸入部６９に外気を取り込む第四吸気口７２、逆に外気へリークしないようにシート状のリード弁形第四逆止弁７３から成る第四吸気手段７４と、逆流時にガス流入する前記吐出部７０に外気を取り込む第五吸入口７５と逆にここから外気へリークしないようにシート状のリード弁形逆止弁７６から成る第五吸気手段７７とを備えている。
【００４６】
また吸入部６９は、ファンボディＢ６６に設けられた吸入部６６ｂと、ファンカバー６８に設けられた吸入部６９ａと連通して構成されている。また吐出部７０は、ファンボディＢ６６に設けられた吐出部７０ａ、ファンボディＢ６６とファンカバー６８の間に設けられた吐出部７０ｂ、吐出部７０ｃ、ファンカバー６８に設けられた吐出部７０ｄと連通して構成されている。また順流時に吸入部６９を経て外気ならびに戻りガスからのゴミ、微粒子物質の流入を防止する第一エアーフィルタ７９を、逆流時に前記吐出部７０に、吸入作用が働く際にゴミや微粒子物質が流入するのを防止する第二エアーフィルタ８０を内設して一体に構成されている。
【００４７】
また各エアーフィルタ７９、８０はポリフェニレンスルフィド（ＰＰＳ樹脂）系の、またはステンレス系の材料で成形されている。
【００４８】
以上の構成からなる可逆形送風制御手段７８を用いれば図２で説明したのと同様の効果が得られるうえにコンパクト化が推進できる。
【００４９】
なお上記各実施例で示した本発明の各送風手段の駆動用電動機として直流電動機でなくブラシレス直流電動機を用いればフォークリフト、自動車、トラック、船舶等分野に実際に搭載しても、直流電動機の整流子部内で発生するスパークの問題がなく、信頼性が高く、また高寿命化が可能となる。
【００５０】
また第一逆止弁、第二逆止弁、第三逆止弁、第四逆止弁、第五逆止弁の逆止弁は無動力形で、かつシート状のリード弁から構成されているので薄形で小形軽量化に利点があり、かつ外気を取り込む際の応答性が良いこと、省エネが良い等の効果が期待できる。
【００５１】
【発明の効果】
以上説明したように本発明の内燃機関用排ガス浄化装置によれば次のような効果が得られる。
（１）請求項１の構成によれば送風制御手段の送風量を可変制御することによって、送風量の変化と共に変化する吸い込み圧力に応じて外気吸い込み量の変化と逆止弁の開度変化
の相乗作用により循環流量の酸素濃度の可変幅が広く取れ、再生時の燃焼温度上昇の抑制、燃焼ムラ防止等を図りつつ確実なフィルタの再生ができ、また外気取入量は無動力で制御できるため制御性と信頼性が高い。
（２）請求項２の構成によれば請求項１の効果に加えてさらに再生初期段階で、フィルタに流入する送風方向と加熱手段の作用方向を相対してパティキュレートを燃焼させることができ、フィルタ端面側のパティキュレートの焼却効果が高く、再生率向上が期待できる。
（３）請求項３または４の構成によれば回路構成が単純化できコンパクト化の度合が高く、この結果低コスト化が図れると同時に回路性能の信頼性が高くなる。
（４）請求項５の構成によれば送風制御手段の小形軽量化が図れる。
（５）請求項６の構成によれば送風制御手段はもちろんシステム全体をさらに小形軽量化できる。
（６）請求項７の構成によれば外気を吸い込むガス中、および再循環回路を経て流入する燃焼ガス中のゴミや微粒子物質を捕獲することができるので、送風制御手段への悪影響を防止でき、高い信頼性と高寿命が期待できる。
（７）請求項８の構成によれば電動機の整流子部内で発生するスパークの問題がなく、信頼性と寿命の向上が図れる。
【図面の簡単な説明】
【図１】本発明の第１の実施例における内燃機関用排ガス浄化装置の構成図
【図２】本発明の第２の実施例における内燃機関用排ガス浄化装置の構成図
【図３】本発明の内燃機関用排ガス浄化装置における送風制御手段の他の実施例を示す構成図
【図４】同送風制御手段の要部拡大図
【図５】本発明の内燃機関用排ガス浄化装置における可逆形送風制御手段の他の実施例を示す構成図
【図６】図５における矢視Ｂ−Ｂ’方向の横断面図
【図７】従来の内燃機関用排ガス浄化装置を示す構成図
【符号の説明】
１再循環形排ガス浄化装置
２第一排気管
３フィルタ
４加熱手段
７排気トップ
８送風制御手段
９再循環回路
９ａ順流循環回路
９ｂ逆流循環回路
１０第一吸気手段
２１吸入部
２２吐出部
２８第一吸気口
２９第一逆止弁
３１可逆形送風制御手段
３２第二吸気口
３３第二逆止弁
３４第二吸気手段
５７ターボ形送風機
５２ファンケーシング
５１吸入部
５８第三吸気口
５９第三逆止弁
６１第三吸気手段
６４渦流形ファン
６９吸入部
７０吐出部
７２、７５吸気口
７３、７６逆止弁
７４、７７吸気手段
２９、３３、５９、７３、７６負圧応動形逆止弁
７９、８０エァーフィルタ
１２運転制御回路
２０、３８、５６、７１電動機[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a filter that collects particulates (particulate matter) contained in exhaust gas discharged from a diesel engine (internal combustion engine), and a filter that collects and removes the collected particulates by heating and burning. The present invention relates to an exhaust gas purifying device for an internal combustion engine that recovers and regenerates fuel.
[0002]
[Prior art]
Diesel engines are characterized by higher combustion efficiency and better durability than gasoline engines, but have the disadvantage of discharging air pollutants. Exhaust gas emitted from diesel engines contains patties (particulate matter) together with nitrogen oxides, and exhaust gas regulations are being strengthened. While efforts are being made to improve fuels such as combustion improvement by delaying fuel injection timing and reduction of sulfur in diesel oil in response to this stricter regulation, there is a technical contradiction between reducing nitrogen oxides and reducing particulates. Currently, it is considered to be a promising solution to reduce nitrogen oxide around the engine and treat the particulates in the exhaust system.
[0003]
Particulates mainly consist of three types of SOF (Solid Organic Fraction), soot, and sulfur compounds. As a method of treating this particulate in the exhaust system, the particulates are treated using an oxidation catalyst system or filter that reduces SOF. A method of collecting is underway. Since the oxidation catalyst method cannot reduce soot, a filter method is preferable. However, in the filter system, if the particulates are continuously collected, the filter is clogged, the flow of exhaust gas becomes worse, and the engine output is reduced or the engine is stopped. On the other hand, at present, technical development for regenerating the collecting ability of the filter is underway. If the amount of particulates collected in the filter becomes too large, the load on the engine increases. In the worst case, the engine is stopped, so it is necessary to remove the particulates at an appropriate time.
[0004]
As a method for regenerating the collection performance of the filter, a method of burning and removing particulates in the filter and a method of supplying high-pressure air and blowing the particulates outside the filter to burn and remove the particulates outside the filter have been proposed. The method of processing outside the filter has a problem of completely removing particulates, and the mainstream of the regeneration method is a method of burning and removing in the filter. It is known that particulates burn from about 600 ° C. As an energy heating means for raising the temperature of the particulates to this high temperature region, a burner method, an electric heater method, a microwave method, or the like is considered.
[0005]
As a filter regeneration device using a microwave heating method, for example, as shown in FIG. 101 The exhaust gas discharged from the first passage pipe 102 ,filter 103 , Connecting pipe 104 , Shut-off valve 105 Through the exhaust top 106 Means for collecting air to the atmosphere, stopping the engine after a certain time, and shut-off valve 105 Temporarily shut off the filter 103 And shut-off valve 105 Microwave heating unit provided between 107 Operate and blow means 108 By air supply port 109 While sending air from the filter 103 The soot accumulated inside is burned, and the combustion gas generated here is passed through the first passage pipe. 102 Branch pipe branched from 110 Open exhaust valve 111 Through the exhaust top 106 There is a reverse flow type exhaust gas purification device composed of a regenerating means that discharges to the filter and recovers the filter performance.
[0006]
In the above configuration, the engine 101 Particulates such as soot are contained in the exhaust gas discharged from the filter, which is filtered by the action of the collecting means. 103 Filter while passing 103 To be collected. After a certain amount of time in the collection process, the engine 101 And stop valve 105 Cut off the microwave heating section 107 Operate the air supply port 109 While sending air from the filter 103 The soot accumulated in the inside is heated and burned, and the combustion gas generated here is branched from the first passage pipe 2 110 Open exhaust valve 111 Through the exhaust top 106 Filter into the atmosphere 103 Performance is restored.
[0007]
Thereafter, the operation of the collecting means is started again, and the same process is repeated. As another conventional example, a recirculation circuit that recirculates the combustion gas at the time of regeneration again into the filter, an external air suction valve and an oxygen sensor are provided, and a combustion gas circulation type exhaust gas purification device (Japanese Patent Laid-Open No. 6-323130). No. Gazette).
[0008]
This device returns the burned gas, mainly carbon dioxide, back to the filter, lowers the oxygen concentration relatively compared to the oxygen concentration in the outside air, suppresses the heat generation temperature during combustion, and at the same time outputs the oxygen sensor output. Accordingly, the outside air intake valve is opened and closed to change the amount of air passing through the filter (the amount of oxygen), thereby reducing the oxygen concentration and suppressing the combustion temperature.
[0009]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, first, among the particulates accumulated in the filter at the time of regeneration, only a part of the particulates starts to burn in the initial stage due to some heating unevenness. The combustion temperature gradually reaches a high temperature. However, on the other hand, a region where the flame still does not burn or a region where the temperature cannot be increased appears, and the temperature distribution has a large temperature difference. As a result, the thermal shock of the filter increases and cracks may occur in the filter. For this reason, the problem that the particulates leaked during the next collection and the collection effect was lost occurred, and the filter could not be reused. Also, if you try to change the amount of air sucked in a smaller direction in order to lower the combustion temperature in the filter, the combustion temperature cannot be suppressed unless it is controlled to be quite small, and on the contrary, the flow rate distribution in the filter is too large. At the same time as unevenness occurs, a residual region of particulates that cannot be completely burned is generated. As a result, there has been a problem that the regeneration rate of the filter (the value obtained by dividing (the collected amount before regeneration−the residual amount after regeneration) by the collected amount before regeneration) is deteriorated. Moreover, when collection and regeneration are repeated, the flow distribution becomes worse and the residual amount tends to increase more and more. Further, the microwave heating means method has a problem that the closer to the end face of the heating surface, the harder the particulates burn. This is a problem that heat radiation is large at the end face, it is difficult to heat up to the ignition temperature, and combustion starts from the particulates in the area slightly in the back, so that there are some particulates in the end face area. As a result, there has been a problem that the regeneration rate of the filter is lowered.
[0010]
Further, according to the output of the oxygen sensor, a combustion gas circulation type exhaust gas purification device (Japanese Patent Laid-Open No. 6-323130) that opens and closes the outside air intake valve, changes the amount of air passing through the filter (oxygen amount), and suppresses the combustion temperature. In this publication, there is a problem in the aging and response of the oxygen sensor sensitivity, and on the other hand, since a suction valve that opens and closes according to the output is added, oxygen that changes simultaneously with the control of the combustion rate of the particulates and the circulation flow rate A large difference in the responsiveness of the concentration occurs. As a result, the control does not follow the actual phenomenon, and a hunting phenomenon such as an overshoot appears in the control characteristics, and there is a problem that it becomes increasingly difficult to control the combustion temperature in the filter within an appropriate range. Furthermore, because the filter is made up of a collection of thin, small filter functions, if local combustion occurs, only the particulates in the local cell will burn, and as this progresses, this part The air resistance of the air flow is reduced, and the air flows more and more in this part while avoiding other particulate areas that are not partitioned by combustion, that is, areas where the air resistance is high.
[0011]
As a result, local combustion becomes more and more active and the combustion temperature rises more and more. Since the oxygen concentration in the entire combustion gas related to the output of one oxygen sensor is averaged, the result is information that there is no change, and the control circuit does not perform the control operation. For this reason, the temperature distribution in the filter has a large temperature difference, and thermal shock is likely to occur in the filter. As a result, it is expected that cracks will occur in the filter. If it is used as it is, there will be a problem that the particulates will leak from the filter during the next collection and there will be no collection effect, and the filter may not be reused. Moreover, if the control set value for the output of the oxygen sensor is changed to suppress the inhalation amount of air in order to avoid the local temperature rise, there is a problem that the area where the combustion does not progress increases conversely, and the regeneration rate becomes worse. It was.
[0012]
In addition, when local combustion in the filter progresses and the combustion of particulates in this part approaches the end, the air resistance further decreases, the amount of air passing therethrough also concentrates, and the flow rate in this part increases and combustion occurs at the same time. The proportion of the amount of air that is not used increases. As a result, as the oxygen concentration increases, the output of the oxygen sensor also increases. Therefore, the intake valve acts on the control circuit to reduce the air supply amount so as to suppress the oxygen concentration. For this reason, there is a problem that particulates that still require oxygen still remain in the cells in other regions, and remain unburned. In addition, the durability, reliability, and responsiveness of the oxygen sensor are poor, and in addition to this, the control mechanism is complicated, so that the cost increases due to an increase in the number of component parts. Therefore, such a conventional combustion gas circulation type exhaust gas purification device cannot be expected to have a sufficient effect.
[0013]
The present invention solves the above-mentioned problems. The first object of the present invention is to increase the regeneration rate while preventing over-burning of particulates and incineration unevenness due to local combustion, and further reduces the size and improves the reliability. This is the purpose of 2.
[0014]
[Means for Solving the Problems]
The present invention provides a first exhaust pipe of an internal combustion engine as a first means for achieving the first object. Disposed between the exhaust top and exhaust A filter that collects particulates contained in the gas, a heating unit that heats the particulates, and a ventilation control unit that has a function of varying the amount of ventilation, A discharge part of the air blowing control means; Of the filter and the air flow control means. Inhalation part Between Produced by combustion reaction of the particulates A recirculation circuit connected for combustion gas flow, and a recirculation circuit between the filter and the suction part of the air flow control means, the first intake port and a first check valve of negative pressure responsive type The structure is provided with intake means.
[0015]
Further, as a second means for achieving the first object, it is disposed between the first exhaust pipe and the exhaust top of the internal combustion engine. Then drain A filter that collects particulates contained in the gas, a heating unit that heats the particulates, a reversible air flow control unit that has a reversible function in the air blowing direction and a variable function of the air flow rate, A discharge part of the reversible air blowing control means; Of the filter and the reversible air flow control means. Inhalation part Between Produced by combustion reaction of the particulates A recirculation circuit connected for combustion gas flow, and between the filter and the reversible air flow control means; In the same direction as the direction of action of the heating means acting on the filter A first intake means comprising a first intake port and a negative pressure responsive first check valve provided in a forward flow recirculation circuit, and between the filter and the reversible air flow control means The air is blown in a direction relative to the direction of action of the heating means acting on the filter A second intake means comprising a second intake port provided in the backflow recirculation circuit and a negative pressure responsive second check valve is provided.
[0016]
In order to achieve the second objective, The reversible air blow control means Control the input voltage The reversible type An operation control circuit having a control function for variably controlling the rotation of the motor of the blower control means ON and OFF, and a regeneration control function for switching the rotation direction of the motor is provided. It is composed. Also, The operation mode at the initial stage of regeneration is determined by the direction of action of the heating means acting on the filter. Reversible A reverse flow regeneration operation mode that operates relative to the air flow direction of the air flow control means, an action direction of the heating means before and after the operation in the reverse flow regeneration operation mode, and the Reversible The operation control circuit is configured to be in the forward flow regeneration operation mode that operates with the blowing direction of the blowing control unit being matched.
[0017]
Further, as means for achieving the second object, air blowing control means And the first air intake means of the air blowing control means A third intake means comprising a third intake port and a negative pressure responsive third check valve is provided between the fan casing and the suction portion. Provided The structure is integrated.
[0018]
As means for achieving the second object, reversible air blow control means and First intake means and second intake means Are a vortex fan having a reversible air blowing function and a suction part of the vortex fan into which gas flows Outside Inhale Suck Mouth And the inlet Negative pressure response type to control opening The opposite of Stop valve And having Inhaler Step This is an internal configuration.
[0019]
Further, in order to improve the reliability of the second object, the air blowing control means Sucking Prevent inflow of particulate matter into the entrance Air The filter is provided.
[0020]
Similarly, in order to improve reliability, the electric function of the air blowing control means is constituted by a brushless DC motor.
[0021]
DESCRIPTION OF THE PREFERRED EMBODIMENT
According to the present invention, in the process of burning and incinerating the particulates collected by the filter by the first means and regenerating the filter, the engine is temporarily stopped or the exhaust gas from the engine is switched to shut off the inflow and the heating. The air and the air blowing control means are operated and heated while air is sent to the filter, and the combustion gas generated at this time is circulated through the recirculation circuit again and returned to the filter to regenerate while suppressing the combustion temperature. If the rotational speed of the air blowing control means is controlled to increase the air blowing amount, the negative pressure increases near the intake port of the recirculation circuit, and the amount of air sucked from the outside also increases. On the other hand, if the amount of air blown by the air blowing control means is reduced, the negative pressure at the intake port is lowered correspondingly, and the amount of external air sucked is also reduced. That is, since the opening degree of the first check valve automatically changes, the amount of suction with respect to the magnitude of the negative pressure changes greatly in the downward direction as compared with the state of the mere intake port. For this reason, the oxygen concentration of the discharge air volume discharged from the ventilation control means also greatly changes to the lower side. Therefore, by controlling the flow rate downward, it is possible to make the flux distribution flowing into the filter uniform, and to reduce the oxygen concentration of the air amount that controls acceleration of overcombustion and local combustion.
[0022]
In addition, in a large negative pressure region, that is, a region where the check valve has a large opening, that is, a region where the amount of air flow is large, the change in the opening with respect to the negative pressure is small. For this reason, the amount of suction is relatively large, but the amount of change in oxygen concentration is small. As a result, when the amount of circulation is greatly increased, the amount of intake air also increases, but the oxygen concentration can be varied in a region where it does not change much. Therefore, the oxygen concentration is kept below a certain value than the oxygen concentration of the outside air and higher than the oxygen concentration at the time of low flow rate, and a large amount of air flow can be sent to the filter while suppressing a rapid temperature rise. It is possible to maintain the combustion temperature in the vicinity of the upper limit while providing a cooling effect, thereby activating and promoting the combustion.
[0023]
In the second means in which the air blowing direction of the air blowing control means flows in opposite directions, in the initial stage of regeneration, the air blowing direction to be fed to the filter is caused to flow in the reverse direction, so-called heating means acting on the filter. The direction and the air blowing direction of the air blowing control means are operated relative to each other. Therefore, even if combustion starts slightly from the particulates that enter the depths of the filter, the air flow direction flows toward the end face on the heating means side, so the particulates in the end face area are affected by high combustion temperature gases. It is forced to burn and incinerated. Since the combustion gas returns to the filter through the recirculation circuit, the oxygen concentration rapidly decreases and the combustion temperature does not increase rapidly. As a result, the thermal shock to the filter is alleviated and the effect of preventing the occurrence of cracks is obtained.
[0024]
On the other hand, after the combustion of the particulates on this end face proceeds for a certain period of time, the blowing direction is changed to the forward flow direction, the direction of the high-temperature combustion gas is changed to the forward flow direction, and the heating action of the heating means is performed in parallel with the forward flow direction. In addition, the combustion of the particulates can be further advanced by the control of the recirculation flow rate and the variable action of the oxygen concentration of the first check valve. As a result, an overall improvement in filter regeneration rate is expected.
[0025]
The first and second intake ports and the first and second check valves provided there perform the same action as described above, and can suppress a rapid increase in the combustion temperature of the filter.
[0026]
Further, the operation mode in the initial stage of regeneration is a reverse flow regeneration operation mode in which the direction of operation of the heating means acting on the filter and the air flow direction of the air blowing control means are operated relative to each other, and after the operation in the reverse flow regeneration operation mode, An operation control circuit that is in a forward flow regeneration operation mode that operates by making the action direction and the air blowing direction of the air blowing control means coincide with each other, or the input voltage is controlled to turn the motor of the air blowing control means ON, OFF, or rotation A circuit having a control function for variably controlling the number and an operation control circuit having a reversible function of the blowing direction by switching the rotation direction of the motor has high circuit performance and reliability, and a compact circuit configuration can be obtained.
In addition, the third intake means, which is composed of a third intake port for taking in outside air between the fan casing and the suction portion of the air blowing control means and the third check valve, is integrated, and the recirculation circuit is downsized and the DC motor is High controllability can be expected.
[0027]
Also, outside air is sucked into the air flow control means consisting of a vortex fan with a reversible circulation function in the air blowing direction, an electric motor with a variable speed function and a forward / reverse rotation function with a variable air flow function. Suck Non-powered type that controls the opening of the air inlet and the air inlet The opposite of Stop valve And having A system with a built-in intake means further simplifies the system and provides high reliability and low cost.
[0028]
Also air blow control means In the inhalation part Prevent inflow of particulate matter Air Those equipped with a filter can prevent the dust from the outside air and the recirculation circuit and particulate matter in the combustion gas from flowing into the fan rotating section.
[0029]
In addition, when a brushless DC motor is used as the motor for the air blowing control means, the problem of sparks generated in the commutator section of the motor is eliminated.
[0030]
A first embodiment of the present invention will be described below with reference to FIG. In FIG. 1, reference numeral 1 denotes an exhaust gas purification device for an internal combustion engine. This device 1 includes a filter 3, a heating means 4 such as a microwave heater, a connecting pipe 5, a valve unit 6, an exhaust top 7, and an air volume variable function. The air supply control unit 8 includes a recirculation circuit 9, a first intake unit 10, a temperature detector 11, and an operation control circuit 12.
[0031]
The heating means (hereinafter referred to as microwave heating means) 4 in this embodiment is configured by connecting a magnetron unit 13, a waveguide 14, and an inlet can body 15. The valve unit 6 has a shut-off valve 16, an exhaust valve 17, and a pull-down function so that the exhaust valve 17 is open when the shut-off valve 16 is closed and the exhaust valve 17 is closed when the shut-off valve 16 is open. It is comprised from the valve | bulb opening / closing unit 18 which has. The air blowing control means 8 includes a turbo fan 19 having a function of changing the air blowing amount, a brushless DC motor 20 that drives the turbo fan 19, a suction part 21, and a discharge part 22. The temperature detector 11 is arranged in the first exhaust pipe 2 to detect the combustion temperature at the filter outlet of a so-called forward flow fan system that sends wind in the same direction as the direction of action of the microwave heating means 4 acting on the filter 3. Has been configured.
[0032]
In the process of collecting particulates, the system connects the first exhaust pipe 2, the outlet can body 23, the filter 3, the inlet can body 15, the connecting pipe 5, the valve unit 6, and the exhaust top 7 in this order. It flows in the order of connection, flows in from the first exhaust pipe 2, passes through the exhaust top 7, and is discharged to the atmosphere.
[0033]
Further, when the particulates are collected by the filter 3 more than a certain amount, the filter 3 is regenerated. This is because the discharge part 22 and the air blowing pipe 24 of the air blowing control means 8, the inlet can body 15, the filter 3 and the outlet can body 23. The first exhaust pipe 2, the bypass pipe 25, the exhaust valve 17, the exhaust top 7, the return pipe 26, the cooling heat exchanger 27, and the recirculation circuit connected to circulate to the suction portion 21 of the air blowing control means 8. 9 is constituted. Furthermore, the exhaust top 7 and the ventilation control A first intake means 10 comprising a first intake port 28 for taking in outside air and a negative pressure responsive first check valve 29 is disposed in a part between the intake portions 21 of the means 8.
[0034]
The operation control circuit 12 performs control for shifting from the collection process to the regeneration process, or vice versa. The operation control circuit 12 is configured to detect the electromagnetic wave intensity of the microwave that changes according to the amount of collection. The control operation is performed based on the output, the operation time, and the value of the temperature detector 11.
[0035]
In the above-described configuration, first, in the collection process, the exhaust gas discharged from the engine which is an internal combustion engine passes through the outlet can body 23, and is opened from the filter 3 through the connecting pipe 5 and the valve opening / closing unit 18. Then, it is discharged from the exhaust top 7 to the atmosphere through the passage of the exhaust valve 17. At this time, the particulates contained in the exhaust gas are collected by the filter 3.
[0036]
Further, in the regeneration process, after detecting that a certain amount of particulates has been collected, the operation control circuit 12 is operated to switch from the collection process to the regeneration process.
First, in the regeneration process, the exhaust gas flowing into the first exhaust pipe 2 from the engine is temporarily shut off (for example, when the exhaust direction is changed by a switching valve or when the engine is temporarily stopped), and the shutoff valve 16 of the valve unit 6 is turned on. The closed and exhaust valve 17 is switched to the open state, and the microwave heating means 4 and the air blowing control means 8 are operated. Thereby, the microwave heating means 4 heats and burns the particulates in the filter 3, and at the same time, air is sent to the filter 3 through the air blowing pipe 24, the connecting pipe 5 and the inlet can body 15 by the operation of the blowing control means 8. It is. This air is consumed as an aid for burning the particulates. Here, the combustion gas generated by the combustion reaction flows through the outlet can 23, the bypass pipe 25, the exhaust valve 17, and the return pipe 26, and is cooled by the cooling heat exchanger 27 to the suction portion 21 of the blowing control means 8. Return and it will be recirculated again. A so-called recirculation circuit 9 is formed.
[0037]
Here, between the exhaust top and the suction portion 21 of the blower control means 8, a first intake port 28 for introducing external air into a part of the recirculation circuit (return pipe 26), and a negative pressure-responsive first reverse Since the first intake means 10 is configured by providing the stop valve 29, the negative pressure increases near the first intake port 28 when the rotational speed of the air supply control means 8 is controlled to increase the air supply amount, and the air is sucked in from the outside. Increase the amount of air Conversely, if the amount of air blown by the air blowing control means 8 is reduced, the negative pressure at the first air inlet 28 is correspondingly reduced and the amount of external air sucked is also reduced. That is, in the present invention having the above configuration, since the first intake means 10 composed of a non-powered check valve is disposed, the degree of opening of the first check valve 29 changes depending on the magnitude of the negative pressure. Since the opening automatically changes, the amount of suction relative to the magnitude of the negative pressure is more than that of a simple intake port. First check valve 29 Will change greatly downward. In particular, since the opening of the first check valve 29 is small in a region where the negative pressure is low, it can be said that the rate of change of the suction amount with respect to the negative pressure is a high region. For this reason, the oxygen concentration of the discharge air volume discharged from the ventilation control means 8 also changes greatly in the lower direction. Therefore, by controlling the flow rate downward, the flow distribution flowing into the filter can be made uniform, and the oxygen concentration in the air amount can be lowered, so that the effect of suppressing overcombustion and local combustion acceleration can be obtained. It is done.
[0038]
Further, in a large negative pressure region, that is, a region where the opening degree of the first check valve 29 is large, that is, a region where the air flow rate is large, the change in the opening degree with respect to the negative pressure is small, but rather is substantially defined by the numerical aperture or the opening diameter. However, although the amount of suction is relatively large, the amount of change in oxygen concentration is small. As a result, when the amount of circulation is greatly increased, the amount of intake air also increases, but the oxygen concentration can be varied in a region where it does not change much. Therefore, the oxygen concentration is kept below a certain value than the oxygen concentration of the outside air and higher than the oxygen concentration at the time of low flow rate, and a large amount of air flow is sent to the filter 3 while suppressing a rapid temperature rise. Therefore, while maintaining the combustion temperature in the vicinity of the upper limit while having the cooling effect by this, the combustion can be activated and promoted, so that the regeneration time can be shortened and the filter can be protected.
[0039]
Note that the increased amount of gas sucked from the first intake port 28 circulates the flow rate returned from the filter 3, that is, a part of the so-called combustion gas flows to the atmosphere via the exhaust top 7 to form a balanced recirculation circuit. . If the relationship between the negative pressure on the suction side with respect to the air flow rate of the air flow control means 8, the opening degree of the first check valve 29, and the suction amount is defined in advance, the discharge air volume of the air flow control means 8, that is, the circulation flow rate In a small region, control is possible with a lower oxygen concentration and with a large change rate of the oxygen concentration. On the other hand, in a region where the circulation flow rate is large, the high oxygen concentration is almost constant and the circulation flow rate can be controlled. It is expected to prevent filter thermal shock, improve the regeneration rate, and shorten the regeneration time due to high controllability.
[0040]
next A bidirectional exhaust gas purifying apparatus according to a second embodiment of the present invention will be described with reference to FIG. In FIG. 2, the difference from the configuration shown in FIG. 1 is that reversible air blowing control means 31 for reversibly changing the air blowing direction flowing into the filter 3 in both directions and the outside air during air circulation in the reverse direction. A second intake port 34 for taking in air, a second intake means 34 including a negative pressure responsive second check valve 33, and a second temperature sensor 35 for detecting the combustion temperature during reverse air blowing are provided. is there. The reversible air blow control means 31 includes a forward flow recirculation unit in which the air blow control means 8 including the first fan 19 and the DC motor 20 that drives the first fan 19, the suction part 21, the discharge part 22, and the first on-off valve 36 are connected in the forward flow direction. Circulation circuit 9a, one second fan 37, DC motor 38, second suction portion of second fan 37 40 Second discharge part 39 The second air flow control means 41 and the second on-off valve 42 for preventing gas inflow are connected in parallel to the backflow recirculation circuit 9b connected in the backflow direction.
In the above configuration, in the initial stage of regeneration, the circulation flow rate is reduced by stopping the air blowing control means 8, closing the first opening / closing valve 36, turning on the second air blowing control means 41, and opening the second opening / closing valve 42. It flows into the filter 3 through the first passage pipe 26, the exhaust valve 17, the bypass pipe 25, and the outlet can body 23 of the recirculation circuit 9, and is opened and closed through the inlet can body 15, the connecting pipe 5, and the second passage pipe 24. It returns to the 2nd ventilation control means 41 from the valve 42, and is recirculated in a reverse flow direction. After a certain time, the second air flow control means 41 is turned off, the second on-off valve 42 is closed, the air flow control means 8 is turned on, and the first on-off valve 36 is opened, so that the circulation flow rate is connected to the second passage pipe 24. It flows into the filter 3 through the pipe 5 and the inlet can body 15, and further returns to the air blowing control means 8 through the outlet can body 23, the bypass pipe 25, the exhaust valve 17, the first passage pipe 26, and the cooling heat exchanger 27. , Recirculated in the forward direction.
[0041]
That is, in this embodiment, in the initial stage of regeneration, the blowing direction sent to the filter 3 is made to flow in the opposite direction, and the acting direction of the heating means 4 acting on the so-called filter and the blowing direction of the blowing control means 8 are operated relative to each other. As a result, even if combustion starts from the particulates that have entered the depths of the filter, the air flow direction flows toward the end surface on the heating means side, so the particulates in the region of the end surface are affected by high combustion temperature gas. Therefore, there is an advantage that it is forced to burn and incinerated. Further, since the combustion gas returns to the filter 3 through the recirculation circuit, the oxygen concentration is rapidly decreased, so that the combustion temperature does not rapidly increase. As a result, the thermal shock to the filter 3 is alleviated and the effect of preventing the occurrence of cracks is obtained. After the end face particulate combustion proceeds for a certain period of time, the blowing direction is changed to the forward flow direction, the high-temperature combustion gas is changed to the forward flow direction, and the microwave heating means 4 is heated in parallel with the forward flow direction. In addition, the combustion of the particulates can be further advanced by the control of the recirculation flow rate and the variable action of the oxygen concentration of the first check valve 29 described above. As a result, an overall improvement in filter regeneration rate is expected.
[0042]
this Initial playback In the regeneration operation of the stage, that is, the air is blown in the reverse direction by the air blowing control means 8 Because By means of the microwave heating means 4, the filter 3 An area that is slightly inward from the end face Even if combustion starts from the particulates, the air flow direction flows toward the end face on the heating means side, so the particulates in the end face area burn under the influence of gas at a high combustion temperature. Since the gas returns to the filter 3 through the recirculation circuit, the amount of oxygen decreases rapidly. This is because the suction part is switched to the discharge side by the reverse air blowing action of the reversible air blowing control means 31, so that the air from the first air intake port 28 is closed by the action of closing the first check valve 29 of the first air intake means 10. This is because there is no uptake. That is, it is only covered by the initial air amount remaining in the air blowing control means and the recirculation circuit. This alone is effective for suppressing a rapid increase in the combustion temperature, but the amount of oxygen necessary for burning the particulates in the filter end face region is insufficient, and the amount of oxygen for promoting the progress of combustion is not sufficient. Therefore, in addition to the above configuration, a second intake means 34 having a second intake port 32 and a second check valve 33 is provided in the recirculation circuit of the discharge system of the filter 3 and the reversible air flow control means 31. There is. Thereby, even when the air is blown in the reverse direction of the air blowing control means 8 at the initial stage of the regeneration operation, it is possible to take in the outside air from the second air intake port 32 and supplement the amount of oxygen necessary for burning the particulates on the filter end face. At the same time, since it is a mixed gas having a low oxygen concentration, a rapid increase in combustion temperature can be suppressed. As a result, the operation of the second intake means 34 can provide a more reliable and high regeneration rate.
[0043]
Next, another embodiment of the air blowing control means will be described with reference to FIGS. FIG. 3 shows the overall structure of the turbo-type air blowing control means, and FIG. 4 shows an enlarged view of the main part of the third air intake means arranged in the fan casing, which is the air blowing of the exhaust gas purification apparatus of the present invention shown in FIG. The control means 8 and the first intake means 10 are configured as a ventilation control means that is integrated. 3 and 4, the returning gas suction passage 50, the third suction portion 51, the fan casing 52, the fan body 53, the turbo-type rotor blades 54 disposed around them, the discharge portion 55, and the aforementioned It consists of a DC motor 56 that drives the rotor blades 54 and constitutes a turbo-type air blow control means 57. And the turbo type air blow control means 57 is the fan casing 52; Third As shown in FIG. 4, a third intake port 58 for taking outside air into the fan casing 52 between the intake portion 51 and a sheet-like reed valve type third check valve so as not to flow backward from the third intake port 58. 59, a third intake means 61 comprising an air inlet 60 provided in the fan casing 52 in the vicinity of the suction portion in order to guide the air sucked from here to the suction portion 51.
[0044]
In the above configuration, the DC motor 56 When the turbo-type rotor blades 54 rotate, the returned combustion gas passes through the suction passage 50 and enters the suction portion 51. At this time, since the region of the suction portion 51 is in a negative pressure state, the air inlet 60 is opened. The third check valve 59 is opened, and air is taken in from the third intake port 58 and mixed with the combustion gas. The gas having a low oxygen concentration mixed here is sent from the discharge unit 55 to the filter 3. Such an air blowing system is a structure in which the air blowing control means 8 and the first air intake means 10 of the exhaust gas purifying apparatus of the present invention shown in FIG. 1 are integrated together, and at the same time, the exhaust gas purifying apparatus of the present invention shown in FIG. The reversible air blow control means 31 has the same configuration as the air blow control means 8 and the first air intake means 10 integrated together, and the air blow control means 41 and the second air intake means 34 integrated together. With the same configuration Yes And the same effect is obtained. Therefore, the turbo-type air blow control means 57 of the present invention can be used by replacing the air blow control means and the intake means of the exhaust gas purifying apparatus shown in FIG. 1 or FIG. 2 with the air blow control means of the present invention.
[0045]
Next, another example of the reversible air blowing control means will be described with reference to FIGS. This reversible air blow control means 78 Is Eddy current fan with reversible function When, Inhalation part And the discharge unit, In discharge part Provided The intake means with a check valve and the suction part or the discharge part are integrally configured with a filter for preventing inflow of dust and particulates in the exhaust gas into the fan. 5 and 6, the vortex fan 64 includes a fan body A 65, a fan body B 66, a vortex rotor blade 67 rotating around the fan body 68, a fan cover 68, a suction portion 69, a discharge portion 70, and the vortex flow rotation. The reversible vortex fan 64 and the fourth intake port 72 for taking outside air into the suction portion 69 into which gas flows during forward flow, and conversely leak to the outside air, are composed of a DC motor 71 that gives rotational power to the blade 67. In order to prevent the leakage, the fourth intake means 74 composed of a sheet-like reed valve type fourth check valve 73 and the fifth intake port 75 for taking outside air into the discharge portion 70 into which gas flows in at the time of backflow are leaked from here to the outside air. In order to prevent this, a fifth intake means 77 comprising a sheet-like reed valve type check valve 76 is provided.
[0046]
The suction part 69 is configured to communicate with a suction part 66 b provided in the fan body B 66 and a suction part 69 a provided in the fan cover 68. The discharge unit 70 communicates with a discharge unit 70 a provided in the fan body B 66, a discharge unit 70 b provided between the fan body B 66 and the fan cover 68, a discharge unit 70 c, and a discharge unit 70 d provided in the fan cover 68. Configured. In addition, the first air filter 79 that prevents inflow of dust and particulate matter from outside air and return gas through the suction portion 69 during forward flow flows into the discharge portion 70 during reverse flow, and dust and particulate matter flows into the discharge portion 70 during the suction action. A second air filter 80 for preventing this is provided in an integrated manner.
[0047]
Each d A The filters 79 and 80 are formed of a polyphenylene sulfide (PPS resin) type or stainless type material.
[0048]
If the reversible air blow control means 78 having the above configuration is used, the same effect as described with reference to FIG.
[0049]
In addition, if a brushless DC motor is used instead of a DC motor as a driving motor for each air blowing means of the present invention shown in the above embodiments, the DC motor can be rectified even if it is actually mounted in the field of forklifts, automobiles, trucks, ships, etc. There is no problem of sparks generated in the child part, the reliability is high, and the life can be extended.
[0050]
The first check valve, the second check valve, the third check valve, the fourth check valve, and the fifth check valve are non-powered and composed of a sheet-like reed valve. Therefore, it can be expected to be advantageous in that it is thin, small and lightweight, has good responsiveness when taking in outside air, and has good energy saving.
[0051]
【The invention's effect】
As described above, according to the exhaust gas purification apparatus for an internal combustion engine of the present invention, the following effects can be obtained.
(1) According to the configuration of the first aspect, by changing the air flow rate of the air flow control means, the change in the outside air intake amount and the check valve opening change in accordance with the suction pressure that changes with the change in the air flow rate
Because of this synergistic action, the variable range of the oxygen concentration in the circulation flow rate can be widened, and the filter can be reliably regenerated while suppressing the increase in the combustion temperature during regeneration, preventing uneven combustion, and the outside air intake amount is controlled without power. High controllability and reliability are possible.
(2) According to the configuration of claim 2, in addition to the effect of claim 1, the particulates can be combusted in the initial stage of regeneration, with the blowing direction flowing into the filter and the direction of action of the heating means being opposed, The incineration effect of the particulates on the filter end face side is high, and an improvement in regeneration rate can be expected.
(3) According to the configuration of claim 3 or 4, the circuit configuration can be simplified and the degree of compactness can be increased. As a result, the cost can be reduced and the reliability of the circuit performance can be improved.
(4) According to the configuration of claim 5, the air blow control means is small. lightweight Can be achieved.
(5) According to the configuration of claim 6, the entire system as well as the air blowing control means are further reduced in size. lightweight Can be
(6) According to the structure of claim 7, dust and particulate matter in the gas that sucks in the outside air and in the combustion gas that flows in through the recirculation circuit can be captured, so that adverse effects on the blowing control means can be prevented. High reliability and long life can be expected.
(7) According to the configuration of claim 8, there is no problem of sparks generated in the commutator portion of the electric motor, and reliability and life can be improved.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an exhaust gas purification apparatus for an internal combustion engine according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram of an exhaust gas purification apparatus for an internal combustion engine in a second embodiment of the present invention.
FIG. 3 is a block diagram showing another embodiment of the air blowing control means in the exhaust gas purification apparatus for an internal combustion engine of the present invention.
FIG. 4 is an enlarged view of a main part of the air blowing control means.
FIG. 5 is a block diagram showing another embodiment of the reversible air blow control means in the exhaust gas purification apparatus for an internal combustion engine of the present invention.
6 is a cross-sectional view in the direction of arrow BB ′ in FIG.
FIG. 7 is a configuration diagram showing a conventional exhaust gas purifying device for an internal combustion engine.
[Explanation of symbols]
1 Recirculation exhaust gas purification system
2 First exhaust pipe
3 filters
4 Heating means
7 exhaust top
8 Blower control means
9 Recirculation circuit
9a Forward flow circuit
9b Backflow circuit
10 First air intake means
21 Inhalation part
22 Discharge part
28 First inlet
29 First check valve
31 Reversible air blow control means
32 Second air inlet
33 Second check valve
34 Second air intake means
57 Turbo blower
52 Fan casing
51 Inhalation part
58 Third inlet
59 Third check valve
61 Third intake means
64 Eddy current fan
69 Inhalation part
70 Discharge part
72, 75 Air intake
73, 76 Check valve
74, 77 Air intake means
29, 33, 59, 73, 76 Negative pressure responsive check valve
79, 80 air filter
12 Operation control circuit
20, 38, 56, 71 Electric motor

Claims

A filter for collecting particulates contained in exhaust gas and disposed between the first exhaust pipe of an internal combustion engine and the exhaust top, a heating means for heating the particulates, a variable function of the air volume A ventilation control unit having a recirculation circuit connected between a discharge unit of the ventilation control unit, a filter, and a suction unit of the ventilation control unit connected to a combustion gas generated by a combustion reaction of the particulate ; An exhaust gas purifying apparatus for an internal combustion engine, comprising a first intake means comprising a first intake port and a negative pressure responsive first check valve in a recirculation circuit between a filter and an intake portion of the blower control means.

A filter for collecting particulates contained in exhaust gas and disposed between the first exhaust pipe of an internal combustion engine and the exhaust top, a heating means for heating the particulate, reversibly function of the air blowing direction and Combustion gas generated by a combustion reaction of the particulates between a reversible air flow control means having a variable function of air flow, a discharge part of the reversible air flow control means, the filter, and a suction part of the reversible air flow control means A recirculation circuit connected for flow, and a first flow recirculation circuit that blows air in the same direction as the direction of action of the heating means acting on the filter between the filter and the reversible airflow control means. action of the heating means acting on said filter in between the first inlet means comprising the air inlet and the negative圧応acting type first check valve, and the filter and the reversible blower control means Direction and the second inlet port and the second check valve second inlet means for an internal combustion engine exhaust gas purifying apparatus which is configured by providing a consisting of negative圧応acting type provided in the backflow recirculation circuit for blowing the relative direction.

The reversible air blow control means controls the input voltage to turn the motor of the reversible air blow control means ON, OFF, or variably controls the rotation speed, and a regeneration control function to switch the rotation direction of the electric motor. An exhaust gas purification apparatus for an internal combustion engine according to claim 2 , further comprising an operation control circuit having

The operation mode of the initial stage of the regeneration includes a reverse flow regeneration operation mode in which the direction of operation of the heating means acting on the filter and the air flow direction of the reversible air flow control means are operated relative to each other, and the operation of the heating means after the reverse flow regeneration operation mode is operated The exhaust gas purifying apparatus for an internal combustion engine according to claim 2, further comprising an operation control circuit configured to operate in a forward flow regeneration operation mode in which an action direction and an air blowing direction of the reversible air blowing control unit are made to coincide.

The air blowing control means and the first air intake means are integrated by providing a third air intake means including a third air inlet and a negative pressure responsive third check valve between the fan casing and the suction portion of the air blowing control means. The exhaust gas purifying device for an internal combustion engine according to claim 1 configured as described above.

Reversible type blower control means and the first inlet means and second inlet means comprises a vortex shape fan having a blowing reversible function, and sucks external air write no air intake port to the suction portion of the vortex form fan gas flows, the intake port of an internal combustion engine for purifying an exhaust gas according to claim 2, wherein configured by internally provided with inlet means and a check valve of the negative圧応Dogata for controlling the opening.

Claim 1, 2, 3, for an internal combustion engine exhaust gas purifying apparatus according to any one of 5, 6 with an air filter for preventing the inflow of particulate substance intake join the club of the blowing control means.

The exhaust gas purification apparatus for an internal combustion engine according to any one of claims 1, 2, 3, 5, 6, and 7, wherein the motor of the air blowing control means is configured by a brushless DC motor.