JP2004346918A - Egr device for diesel engine - Google Patents

Egr device for diesel engine Download PDF

Info

Publication number
JP2004346918A
JP2004346918A JP2003148183A JP2003148183A JP2004346918A JP 2004346918 A JP2004346918 A JP 2004346918A JP 2003148183 A JP2003148183 A JP 2003148183A JP 2003148183 A JP2003148183 A JP 2003148183A JP 2004346918 A JP2004346918 A JP 2004346918A
Authority
JP
Japan
Prior art keywords
egr
cooler
pipe
gas
egr gas
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP2003148183A
Other languages
Japanese (ja)
Other versions
JP4203355B2 (en
Inventor
Nobuaki Yoshida
信昭 吉田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
UD Trucks Corp
Original Assignee
UD Trucks Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by UD Trucks Corp filed Critical UD Trucks Corp
Priority to JP2003148183A priority Critical patent/JP4203355B2/en
Publication of JP2004346918A publication Critical patent/JP2004346918A/en
Application granted granted Critical
Publication of JP4203355B2 publication Critical patent/JP4203355B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
    • F02M26/22—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with coolers in the recirculation passage
    • F02M26/23—Layout, e.g. schematics
    • F02M26/25—Layout, e.g. schematics with coolers having bypasses

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust-Gas Circulating Devices (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide an EGR device enhanced in safety by preventing the abnormal pressure rise of an EGR cooler regarding the EGR device for a diesel engine. <P>SOLUTION: A bypass passage bypassing the EGR cooler is connected between an EGR pipe on the EGR gas upper reaches and the EGR pipe on the EGR gas lower reaches of the EGR cooler, or between the EGR pipe on the EGR gas upper reaches of the EGR cooler and an engine intake system. A selector valve is mounted to a branch part between the bypass passage and the EGR pipe on the EGR gas upper reaches. A manometer is mounted to the EGR gas upper reaches of the selector valve, and a thermometer is mounted to a refrigerant lead-out port of the EGR cooler. A control means performs opening/closing control of the selector valve to bypass EGR gas to the bypass passage when the detection value of either one of the manometer and thermometer reaches a predetermined set value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

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のＥＧＲ装置に関する。
【０００２】
【従来の技術】
ディーゼルエンジン（以下、「エンジン」という）の燃焼時に発生する窒素酸化物（ＮＯＸ ）を低減するため、従来、排ガスの一部をエンジンの吸気系に排気還流（以下、「ＥＧＲ」という）させるＥＧＲ装置が知られている。
窒素酸化物は、高温の排ガスのもとで空気中の酸素と窒素が反応して生成されるため、ＥＧＲ装置は、ＥＧＲによって燃焼温度を下げることによりＯ２＋Ｎ２→２ＮＯの反応を抑制して窒素酸化物の排出を低減させるものである。
【０００３】
そして、吸気系にＥＧＲさせるＥＧＲガスの温度を下げるほど、燃焼時のスモークの悪化を抑え、窒素酸化物の発生が減少することが知られている。
そこで、昨今では、エンジンの吸気系と排気系との間に接続したＥＧＲパイプに、エンジン冷却水等を冷媒とするＥＧＲクーラーを装着し、ＥＧＲパイプを流下するＥＧＲガスをこのＥＧＲクーラーで熱交換させてＥＧＲガス温度を下げる方法が広く採用されている（例えば、特許文献１〜３参照。）。
【０００４】
【特許文献１】
特開２００３−７４４１７号公報（段落番号「００１０」〜「００３０」、図１）
【特許文献２】
特開２００３−８３１７４号公報（段落番号「００１５」〜「００２３」、図１）
【特許文献３】
特開２００３−７５０９１号公報（段落番号「０００３」〜「０００８」、図１）
【０００５】
【発明が解決しようとする課題】
このように、従来、ＥＧＲ装置にＥＧＲクーラーを組み込んでＥＧＲガスの温度低下を図っているが、万が一何らかの原因でエンジンが異常燃焼してＥＧＲガス温度が上昇した場合、ＥＧＲガスと熱交換された冷却水が沸騰し、ＥＧＲクーラー内の圧力が異常に上昇してＥＧＲクーラーが破損してしまう事態が想定される。
【０００６】
また、ＥＧＲクーラーを流下するＥＧＲガスにはススが混入しているため、長期に亘る使用でＥＧＲクーラー内のチューブがススで目詰まりを起こして、熱交換効率が低下してしまう虞もあった。
本発明は斯かる実情に鑑み案出されたもので、ＥＧＲクーラーの異常な圧力上昇を防止して安全性の向上を図り、併せてＥＧＲクーラーの目詰まりによる熱交換効率の低下防止を図ったエンジンのＥＧＲ装置を提供することを目的とする。
【０００７】
【課題を解決するための手段】
斯かる目的を達成するため、請求項１に係る発明は、エンジンの吸気系と排気系との間に接続されたＥＧＲパイプと、当該ＥＧＲパイプに装着されたＥＧＲクーラーと、ＥＧＲクーラーよりＥＧＲガス上流側のＥＧＲパイプに装着されたＥＧＲバルブと、運転状況検出手段の検出値を基に、予め設定したＥＧＲ領域で上記ＥＧＲバルブを開放制御する制御手段とを備えたエンジンのＥＧＲ装置に於て、上記ＥＧＲクーラーよりＥＧＲガス上流側とＥＧＲガス下流側のＥＧＲパイプとの間、または、ＥＧＲクーラーよりＥＧＲガス上流側のＥＧＲパイプとエンジン吸気系との間にＥＧＲクーラーをバイパスするバイパス通路を接続し、当該バイパス通路と、ＥＧＲガス上流側のＥＧＲパイプとの分岐部に切換えバルブを装着すると共に、当該切換えバルブのＥＧＲガス上流側に圧力計を装着し、ＥＧＲクーラーの冷媒導出口に温度計を装着し、前記制御手段は、圧力計と温度計のいずれか一方の検出値が予め設定された設定値に達したとき、上記切換えバルブを開閉制御してＥＧＲガスをバイパス通路へバイパスさせることを特徴とする。
【０００８】
そして、請求項２に係る発明は、請求項１記載のエンジンのＥＧＲ装置に於て、バイパス通路と、ＥＧＲクーラーよりＥＧＲガス下流側のＥＧＲパイプとの合流部に切換えバルブを装着し、制御手段は、圧力計と温度計のいずれか一方の検出値が予め設定された設定値に達したとき、当該切換えバルブを開閉制御して、ＥＧＲクーラー側のＥＧＲガス流路を閉鎖することを特徴とし、請求項３に係る発明は、請求項１または請求項２記載のエンジンのＥＧＲ装置に於て、圧力計と温度計の検出値の異常状況を報知する報知手段を備え、制御手段は、圧力計または温度計の検出値が予め設定された設定値に達したとき、当該報知手段を作動させることを特徴としている。
【０００９】
（作用）
各請求項に係る発明によれば、エンジンが予め設定したＥＧＲ領域にあるとき、制御手段は、ＥＧＲバルブを開放して排ガスの一部をＥＧＲパイプからエンジンの吸気系にＥＧＲさせる。
従って、ＥＧＲパイプを流下するＥＧＲガスは、ＥＧＲクーラーで熱交換されて冷却されることとなる。
【００１０】
そして、例えば何らかの原因でエンジンが異常燃焼等してＥＧＲガス温度が上昇した結果、冷媒の温度が上昇して温度計で検出された検出値が設定値に達すると、或いはまた、長期に亘る使用でＥＧＲクーラー内のチューブがススで目詰まりを起こすと、ＥＧＲクーラー内に導入されるＥＧＲガスの圧力が上昇するが、圧力計で検出された検出値が設定値に達すると、制御手段は、切換えバルブでＥＧＲクーラーへの流路を閉鎖すると共に、切換えバルブを作動させてバイパス通路を開放するため、ＥＧＲガスはＥＧＲクーラーをバイパスしてバイパス通路へ流れ込み、バイパス通路へとバイパスしたＥＧＲガスはエンジンの吸気系にＥＧＲされることとなる。
【００１１】
また、請求項２に係る発明によれば、バイパス通路へのＥＧＲガスのバイパス時に、切換えバルブがＥＧＲクーラーへのＥＧＲガス流路を遮断してＥＧＲクーラーへのＥＧＲガスの吹き返しを防止する。
そして、請求項３に係る発明によれば、バイパス通路へのＥＧＲガスのバイパス時に、制御手段は、報知手段を作動させてドライバーに異常状況を報知する。
【００１２】
【発明の実施の形態】
以下、本発明の実施形態を図面に基づいて詳細に説明する。
図１は請求項１乃至請求項３の一実施形態に係るＥＧＲ装置を示し、図に於て、１はエンジン３のインテークマニホールド５に接続された吸気通路（吸気管）、７はエンジン３のエキゾーストマニホールド９に接続された排気通路（排気管）で、吸気通路１を介して吸入空気Ａがエンジン３に流入し、排気通路７の排ガス下流側には消音器１１が装着されている。
【００１３】
そして、吸気通路１と、消音器１１より排ガス上端側の排気通路７との間にＥＧＲパイプ１３が接続されており、当該ＥＧＲパイプ１３にはＥＧＲバルブ１５が排気通路７との接続部近傍に装着されている。
ＥＧＲバルブ１５は、ＥＣＵ（制御手段）１７の指令を受けたアクチュエータ（図示せず）の駆動でＥＧＲパイプ１３のＥＧＲガス流路を開閉するもので、ＥＣＵ１７には、エンジン３に装着した図示しない回転センサと運転負荷を検出するアクスル開度センサの信号が入力されている。そして、従来と同様、ＥＣＵ１７は、両センサからのエンジン回転数とアクスル開度信号を基に、予め設定されたＥＧＲ領域（排気温度の低いエンジンの低負荷域）でアクチュエータを介してＥＧＲバルブ１５を開操作して、排ガスＧの一部をＥＧＲパイプ１３にＥＧＲさせるようになっている。
【００１４】
そして、ＥＧＲパイプ１３には、エンジン冷却水（以下、「冷却水」という）Ｗを用いた水冷式のＥＧＲクーラー１９が装着されており、従来と同様、ＥＧＲクーラー１９内の複数のチューブ（図示せず）を流下するＥＧＲガスＧ−１を、インレットパイプ２１とアウトレットパイプ（冷媒導出口）２３を介してＥＧＲクーラー１９内に導出入する冷却水Ｗで熱交換させて、ＥＧＲガス温度を下げるようになっている。
【００１５】
尚、図示するように冷却水ＷをＥＧＲクーラー１９内に導入するインレットパイプ２１はＥＧＲクーラー１９のＥＧＲガス下流側に接続され、また、冷却水ＷをＥＧＲクーラー１９から導出させるアウトレットパイプ２３はＥＧＲクーラー１９のＥＧＲガス上流側に接続されている。
また、図中、２５はＥＧＲクーラー１９をバイパスして、当該ＥＧＲクーラー１９のＥＧＲガス上流側とＥＧＲガス下流側のＥＧＲパイプ１３間を繋ぐバイパス通路で、当該バイパス通路２５とＥＧＲパイプ１３との分岐部に切換えバルブ２７，２９が装着されると共に、バイパス通路２５とＥＧＲパイプ１３との合流部に切換えバルブ３１が装着されている。
【００１６】
而して、図示するように切換えバルブ２７，３１は、夫々、ＥＧＲパイプ１３中に装着され、また、切換えバルブ２９はバイパス通路２５中に装着されており、これらは夫々、ＥＣＵ１７の指令で作動するアクチュエータ（図示せず）によって開閉動作する。
そして、既述したアウトレットパイプ２３中に、ＥＧＲ時の冷却水Ｗの温度を検出する温度計３５が装着されると共に、前記切換えバルブ２７のＥＧＲガス上流側のＥＧＲパイプ１３内に、ＥＧＲガスＧ−１の圧力を検出する圧力計３３が装着されており、これらの検出信号は前記ＥＣＵ１７に入力されている。そして、ＥＣＵ１７のメモリには、冷却水Ｗの異常温度値とＥＧＲガスＧ−１の異常圧力値が予め設定値として設定，記憶されており、ＥＣＵ１７は、ＥＧＲ開始時及び圧力計３３と温度計３５で検出された検出値のいずれもが上記設定値に達しない状態でＥＧＲが行われているときは、アクチュエータを介して切換えバルブ２７，３１を作動させてＥＧＲクーラー１９の流路を開放し、同時に切換えバルブ２９を作動させてバイパス通路２５を閉鎖させるようになっている。
【００１７】
従って、ＥＧＲされたＥＧＲガスＧ−１は、ＥＧＲパイプ１３を介して総てＥＧＲクーラー１９を流下する。
そして、例えば何らかの原因でエンジンが異常燃焼してＥＧＲガス温度が上昇したり、長期に亘る使用でＥＧＲクーラー１９内のチューブがススで目詰まりを起こしてＥＧＲガスＧ−１に対する背圧が上昇した結果、圧力計３３や温度計３５で検出された検出値のいずれか一方が既述した設定値に達すると、ＥＣＵ１７は、アクチュエータを介して切換えバルブ２７，３１を作動させてＥＧＲクーラー１９の流路を閉鎖すると共に、切換えバルブ２９を作動させてバイパス通路２５を開放し、ＥＧＲガスＧ−１を総てバイパス通路２５へバイパスさせるようになっている。
【００１８】
また、車室内のインストルメントパネルには、既述した圧力と温度の異常状況を報知する報知手段として警報ブザー３７とランプ３９が装着されており、ＥＣＵ１７は上述の如くＥＧＲガスＧ−１をバイパス通路２５へバイパスさせると同時に、これらを作動させてドライバーにその旨を報知するようになっている。
本実施形態に係るＥＧＲ装置４１はこのように構成されているから、駆動するエンジン３がＥＧＲ領域にあるとき、ＥＣＵ１７は、ＥＧＲバルブ１５を開操作して排ガスＧの一部をＥＧＲパイプ１３からエンジン３の吸気系にＥＧＲさせる。
【００１９】
そして、ＥＣＵ１７は、ＥＧＲ開始時及び圧力計３３と温度計３５で検出された検出値のいずれもが設定値に達しない状態でＥＧＲが行われているときに、切換えバルブ２７，３１でＥＧＲクーラー１９の流路を開放し、同時に切換えバルブ２９でバイパス通路２５を閉鎖させるため、ＥＧＲされたＥＧＲガスＧ−１は、総てＥＧＲクーラー１９で熱交換されて吸気通路１へと流下する。
【００２０】
一方、既述したように例えば何らかの原因でエンジンが異常燃焼してＥＧＲガス温度が上昇したり、長期に亘る使用でＥＧＲクーラー１９内のチューブがススで目詰まりを起こしてＥＧＲガスＧ−１に対する背圧が上昇した結果、圧力計３３や温度計３５で検出された検出値のいずれか一方が既述した設定値に達すると、アクチュエータを介して切換えバルブ２７，３１でＥＧＲクーラー１９の流路を閉鎖すると共に、切換えバルブ２９を作動させてバイパス通路２５を開放するため、ＥＧＲガスＧ−１は総てＥＧＲクーラー１９をバイパスしてバイパス通路２５へ流れ込む。
【００２１】
そして、バイパス通路２５へとバイパスしたＥＧＲガスＧ−１は、ＥＧＲパイプ１３との合流部で再びＥＧＲパイプ１３に流入して吸気通路１へと流下するが、このとき、切換えバルブ３１がＥＧＲクーラー１９へのＥＧＲガス流路を遮断して、ＥＧＲクーラー１９へのＥＧＲガスＧ−１の吹き返しを防止する。
また、これと同時に、ＥＣＵ１７は警報ブザー３７とランプ３９を作動させてドライバーにその旨を報知することとなる。
【００２２】
このように本実施形態は、エンジン３の異常燃焼等によってＥＧＲクーラー１９の冷却水温度が異常に上昇したり、ＥＧＲクーラー１９に流入するＥＧＲガスＧ−１の圧力が異常に上昇したときに、ＥＧＲクーラー１９をバイパスさせてＥＧＲガスＧ−１をバイパス通路２５からエンジン３の吸気系にＥＧＲさせるようにしたので、ＥＧＲクーラー１９の圧力上昇等による破損を防止することができ、ＥＧＲ装置４１の安全性を高めることが可能となった。
【００２３】
また、既述したように本実施形態は、ＥＧＲクーラー１９をバイパスさせてＥＧＲガスＧ−１をエンジン３の吸気系にＥＧＲさせる際に、警報ブザー３７とランプ３９でドライバーにその旨を報知させるように構成したので、ドライバーは異常状況を速やかに把握することが可能となって早期のメンテナンスを行うことができ、この結果、冷却効率が低下したままＥＧＲクーラー１９を使用することがなくなり、更にまた、バイパス時に切換えバルブ３１でＥＧＲガス流路を遮断することで、ＥＧＲクーラー１９へのＥＧＲガスＧ−１の吹き返しを防止することができる利点を有する。
【００２４】
尚、上記実施形態は、水冷式のＥＧＲクーラーを用いたＥＧＲ装置に本発明を適用したが、本発明は空冷式のＥＧＲクーラーを装着したＥＧＲ装置にも適用できることは勿論である。
また、上記実施形態では、バイパス通路２５のＥＧＲガス下流側をＥＧＲパイプ１３に接続したが、バイパス通路２５のＥＧＲガス下流側を吸気通路１に直接接続してもよく、斯かる実施形態によっても、上記実施形態と同様、所期の目的を達成することが可能である。
【００２５】
【発明の効果】
以上述べたように、各請求項に係る発明は、エンジンの異常燃焼等によってＥＧＲガス温度が上昇したり、長期に亘る使用でＥＧＲクーラー内のチューブがススで目詰まりを起こしてＥＧＲガスに対する背圧が上昇した際に、ＥＧＲクーラーをバイパスさせてＥＧＲガスをエンジンの吸気系にＥＧＲさせるように構成したので、ＥＧＲクーラー内の圧力上昇による破損を防止してＥＧＲ装置の安全性を高めることが可能となり、また、冷却効率が低下したＥＧＲクーラーの使用を防止することができる利点を有する。
【００２６】
そして、請求項２に係る発明によれば、ＥＧＲガスのバイパス時に、ＥＧＲクーラー側のＥＧＲガス流路を切換えバルブで遮断するため、ＥＧＲクーラーへのＥＧＲガスの吹き返しを防止することができ、また、請求項３に係る発明によれば、ドライバーは報知手段によって異常状況を速やかに把握することができるため、ＥＧＲクーラーの早期のメンテナンスを行うことができる利点を有する。
【図面の簡単な説明】
【図１】請求項１乃至請求項３の一実施形態に係るＥＧＲ装置の構成図である。
【符号の説明】
１ 吸気通路
３ エンジン
５ インテークマニホールド
７ 排気通路
９ エキゾーストマニホールド
１１ 消音器
１３ ＥＧＲパイプ
１５ ＥＧＲバルブ
１７ ＥＣＵ
１９ ＥＧＲクーラー
２１ インレットパイプ
２３ アウトレットパイプ
２５ バイパス通路
２７，２９，３１ 切換えバルブ
３３ 圧力計
３５ 温度計
３７ 警報ブザー
３９ 警報ランプ
４１ ＥＧＲ装置[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an EGR device for a diesel engine.
[0002]
[Prior art]
Diesel engine (hereinafter, referred to as "engine") for reducing the nitrogen oxides generated during combustion of the (NO X), conventionally, the exhaust gas recirculating part of exhaust gases to the intake system of the engine (hereinafter, referred to as "EGR") makes EGR devices are known.
Since nitrogen oxides are produced by the reaction of oxygen and nitrogen in the air under high-temperature exhaust gas, the EGR device suppresses the reaction of O 2 + N 2 → 2NO by lowering the combustion temperature by EGR. To reduce the emission of nitrogen oxides.
[0003]
It is known that, as the temperature of the EGR gas to be subjected to EGR to the intake system is lowered, deterioration of smoke during combustion is suppressed, and generation of nitrogen oxides is reduced.
Therefore, in recent years, an EGR cooler that uses engine cooling water or the like as a refrigerant is mounted on an EGR pipe connected between an intake system and an exhaust system of an engine, and the EGR gas that flows down the EGR pipe exchanges heat with the EGR cooler. A method of lowering the EGR gas temperature by adopting such a method is widely used (for example, see Patent Documents 1 to 3).
[0004]
[Patent Document 1]
JP 2003-74417 A (paragraph numbers “0010” to “0030”, FIG. 1)
[Patent Document 2]
JP 2003-83174 A (paragraph numbers “0015” to “0023”, FIG. 1)
[Patent Document 3]
JP-A-2003-75091 (paragraph numbers “0003” to “0008”, FIG. 1)
[0005]
[Problems to be solved by the invention]
As described above, conventionally, the EGR cooler is incorporated in the EGR device to reduce the temperature of the EGR gas. However, if the EGR gas temperature rises due to abnormal combustion of the engine for some reason, heat exchange with the EGR gas occurs. It is assumed that the cooling water boils, the pressure inside the EGR cooler rises abnormally, and the EGR cooler is damaged.
[0006]
In addition, since soot is mixed in the EGR gas flowing down the EGR cooler, the tube in the EGR cooler may be clogged with soot during long-term use, and the heat exchange efficiency may be reduced. .
The present invention has been devised in view of such circumstances, and has been aimed at preventing abnormal pressure rise of the EGR cooler to improve safety, and at the same time, preventing reduction in heat exchange efficiency due to clogging of the EGR cooler. It is an object to provide an EGR device for an engine.
[0007]
[Means for Solving the Problems]
In order to achieve such an object, an invention according to claim 1 includes an EGR pipe connected between an intake system and an exhaust system of an engine, an EGR cooler mounted on the EGR pipe, and an EGR cooler provided by the EGR cooler. An EGR device for an engine, comprising: an EGR valve mounted on an upstream EGR pipe; and control means for opening and controlling the EGR valve in a preset EGR region based on a detection value of an operating condition detecting means. A bypass passage for bypassing the EGR cooler is connected between the EGR gas upstream of the EGR cooler and the EGR pipe downstream of the EGR gas or between the EGR pipe upstream of the EGR cooler and the engine intake system. At the same time, a switching valve is attached to the branch between the bypass passage and the EGR pipe on the upstream side of the EGR gas. A pressure gauge is mounted on the upstream side of the EGR gas of the valve, and a thermometer is mounted on the refrigerant outlet of the EGR cooler. The control means sets a detection value of one of the pressure gauge and the thermometer to a preset value. When the value reaches the value, the switching valve is controlled to open and close to bypass the EGR gas to the bypass passage.
[0008]
According to a second aspect of the present invention, in the EGR device for the engine according to the first aspect, a switching valve is mounted at a junction between the bypass passage and an EGR pipe downstream of the EGR cooler from the EGR gas. When one of the detected values of the pressure gauge and the thermometer reaches a preset value, the switching valve is opened and closed to close the EGR gas flow path on the EGR cooler side. According to a third aspect of the present invention, in the EGR device for an engine according to the first or second aspect, there is provided a notifying unit for notifying an abnormal state of the detection values of the pressure gauge and the thermometer, and the control unit includes When the detection value of the thermometer or the thermometer reaches a preset value, the notifying means is activated.
[0009]
(Action)
According to the invention of each claim, when the engine is in the preset EGR region, the control means opens the EGR valve and causes a part of the exhaust gas to EGR from the EGR pipe to the intake system of the engine.
Therefore, the EGR gas flowing down the EGR pipe is exchanged by the EGR cooler and cooled.
[0010]
Then, for example, as a result of the engine abnormally burning for some reason and the EGR gas temperature rising, as a result, the temperature of the refrigerant rises and the detection value detected by the thermometer reaches the set value, or if the refrigerant is used for a long time. When the tube in the EGR cooler is clogged with soot, the pressure of the EGR gas introduced into the EGR cooler increases. However, when the detection value detected by the pressure gauge reaches a set value, the control means: Since the switching valve closes the flow path to the EGR cooler and activates the switching valve to open the bypass passage, the EGR gas bypasses the EGR cooler and flows into the bypass passage. EGR is performed in the intake system of the engine.
[0011]
According to the invention of claim 2, when the EGR gas is bypassed to the bypass passage, the switching valve shuts off the EGR gas flow path to the EGR cooler to prevent the EGR gas from returning to the EGR cooler.
According to the third aspect of the invention, when the EGR gas is bypassed to the bypass passage, the control means operates the notification means to notify the driver of the abnormal situation.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an EGR device according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an intake passage (intake pipe) connected to an intake manifold 5 of the engine 3; In an exhaust passage (exhaust pipe) connected to the exhaust manifold 9, intake air A flows into the engine 3 via the intake passage 1, and a muffler 11 is mounted on the exhaust passage 7 downstream of the exhaust gas.
[0013]
An EGR pipe 13 is connected between the intake passage 1 and the exhaust passage 7 on the exhaust gas upper end side of the muffler 11, and an EGR valve 15 is connected to the EGR pipe 13 in the vicinity of a connection portion with the exhaust passage 7. It is installed.
The EGR valve 15 opens and closes the EGR gas flow path of the EGR pipe 13 by driving an actuator (not shown) which has received a command from the ECU (control means) 17. Signals from a rotation sensor and an axle opening sensor for detecting an operation load are input. Then, as in the prior art, based on the engine speed and the axle opening signal from the two sensors, the ECU 17 sends the EGR valve 15 via an actuator in a preset EGR range (low load range of the engine having a low exhaust gas temperature). Is opened to cause a part of the exhaust gas G to be EGR to the EGR pipe 13.
[0014]
A water-cooled EGR cooler 19 using engine cooling water (hereinafter, referred to as “cooling water”) W is mounted on the EGR pipe 13, and a plurality of tubes (see FIG. (Not shown), the EGR gas G-1 is subjected to heat exchange with the cooling water W introduced into the EGR cooler 19 through the inlet pipe 21 and the outlet pipe (refrigerant outlet) 23 to lower the EGR gas temperature. It has become.
[0015]
As shown, an inlet pipe 21 for introducing the cooling water W into the EGR cooler 19 is connected to the EGR gas downstream of the EGR cooler 19, and an outlet pipe 23 for leading the cooling water W from the EGR cooler 19 is connected to the EGR cooler 19. The cooler 19 is connected to the upstream side of the EGR gas.
In the figure, reference numeral 25 denotes a bypass passage which bypasses the EGR cooler 19 and connects the EGR gas upstream side of the EGR cooler 19 and the EGR pipe 13 downstream of the EGR gas. Switching valves 27 and 29 are mounted on the branch portion, and a switching valve 31 is mounted on a junction of the bypass passage 25 and the EGR pipe 13.
[0016]
As shown in the figure, the switching valves 27 and 31 are respectively mounted in the EGR pipe 13, and the switching valve 29 is mounted in the bypass passage 25, and these are operated by commands of the ECU 17 respectively. The opening / closing operation is performed by an actuator (not shown).
A thermometer 35 for detecting the temperature of the cooling water W during EGR is mounted in the outlet pipe 23 described above, and the EGR gas G is provided in the EGR pipe 13 on the upstream side of the EGR gas of the switching valve 27. A pressure gauge 33 for detecting a pressure of −1 is mounted, and these detection signals are input to the ECU 17. In the memory of the ECU 17, an abnormal temperature value of the cooling water W and an abnormal pressure value of the EGR gas G-1 are set and stored in advance as set values. When EGR is performed in a state where none of the detection values detected at 35 reaches the above set value, the switching valves 27 and 31 are operated via the actuator to open the flow path of the EGR cooler 19. At the same time, the switching valve 29 is operated to close the bypass passage 25.
[0017]
Therefore, all the EGR gas G-1 subjected to the EGR flows down the EGR cooler 19 via the EGR pipe 13.
Then, for example, the engine abnormally burns for some reason and the temperature of the EGR gas rises, or the tube in the EGR cooler 19 is clogged with soot due to long-term use, and the back pressure against the EGR gas G-1 rises. As a result, when one of the detection values detected by the pressure gauge 33 or the thermometer 35 reaches the above-described set value, the ECU 17 operates the switching valves 27 and 31 via the actuator to flow the flow of the EGR cooler 19. The passage is closed, the switching valve 29 is operated to open the bypass passage 25, and all the EGR gas G- 1 is bypassed to the bypass passage 25.
[0018]
Further, an alarm buzzer 37 and a lamp 39 are mounted on the instrument panel in the vehicle cabin as a notifying means for notifying the above-mentioned abnormal condition of pressure and temperature, and the ECU 17 bypasses the EGR gas G-1 as described above. At the same time as bypassing to the passage 25, these are actuated to notify the driver to that effect.
Since the EGR device 41 according to the present embodiment is configured as described above, when the driven engine 3 is in the EGR range, the ECU 17 opens the EGR valve 15 to remove a part of the exhaust gas G from the EGR pipe 13. EGR is performed in the intake system of the engine 3.
[0019]
The ECU 17 controls the switching valves 27 and 31 to operate the EGR cooler at the start of the EGR and when the EGR is performed in a state where none of the detection values detected by the pressure gauge 33 and the thermometer 35 reach the set values. In order to open the flow path 19 and close the bypass passage 25 with the switching valve 29 at the same time, all the EGR gas G-1 subjected to EGR is subjected to heat exchange in the EGR cooler 19 and flows down to the intake passage 1.
[0020]
On the other hand, as described above, for example, the engine abnormally burns for some reason and the temperature of the EGR gas rises, or the tube in the EGR cooler 19 is clogged with soot due to long-term use, and the EGR gas G-1 When one of the detection values detected by the pressure gauge 33 or the thermometer 35 reaches the above-mentioned set value as a result of the increase of the back pressure, the switching valves 27 and 31 are actuated to switch the flow path of the EGR cooler 19 through the actuators. Is closed and the switching valve 29 is operated to open the bypass passage 25, so that all the EGR gas G-1 bypasses the EGR cooler 19 and flows into the bypass passage 25.
[0021]
Then, the EGR gas G-1 that has bypassed to the bypass passage 25 flows into the EGR pipe 13 again at the junction with the EGR pipe 13 and flows down to the intake passage 1. At this time, the switching valve 31 is operated by the EGR cooler. The EGR gas flow path to the EGR gas 19 is shut off to prevent the EGR gas G-1 from returning to the EGR cooler 19.
At the same time, the ECU 17 activates the alarm buzzer 37 and the lamp 39 to notify the driver of this.
[0022]
As described above, the present embodiment is configured such that when the coolant temperature of the EGR cooler 19 abnormally rises due to abnormal combustion of the engine 3 or the pressure of the EGR gas G-1 flowing into the EGR cooler 19 abnormally rises, Since the EGR cooler 19 is bypassed to allow the EGR gas G-1 to be EGR from the bypass passage 25 to the intake system of the engine 3, it is possible to prevent the EGR cooler 19 from being damaged due to a rise in pressure or the like. It has become possible to increase safety.
[0023]
Further, as described above, in the present embodiment, when the EGR gas G-1 is bypassed to the EGR cooler 19 and the EGR gas G-1 is EGR to the intake system of the engine 3, the driver is notified by the alarm buzzer 37 and the lamp 39. With such a configuration, the driver can quickly grasp the abnormal situation, and can perform early maintenance. As a result, the driver does not use the EGR cooler 19 while the cooling efficiency is reduced. In addition, by switching off the EGR gas flow path by the switching valve 31 at the time of bypass, there is an advantage that the backflow of the EGR gas G-1 to the EGR cooler 19 can be prevented.
[0024]
In the above embodiment, the present invention is applied to an EGR device using a water-cooled EGR cooler. However, the present invention can of course be applied to an EGR device equipped with an air-cooled EGR cooler.
Further, in the above embodiment, the EGR gas downstream side of the bypass passage 25 is connected to the EGR pipe 13, but the EGR gas downstream side of the bypass passage 25 may be directly connected to the intake passage 1, and according to such an embodiment. As in the above-described embodiment, the intended purpose can be achieved.
[0025]
【The invention's effect】
As described above, in the invention according to each claim, the temperature of the EGR gas rises due to abnormal combustion of the engine or the like, and the tube in the EGR cooler is clogged with soot over a long period of use, so that the backing of the EGR gas is prevented. When the pressure is increased, the EGR cooler is bypassed to allow the EGR gas to be introduced into the intake system of the engine so that the EGR gas is prevented from being damaged due to an increase in the pressure in the EGR cooler, thereby improving the safety of the EGR device. This has the advantage that the use of an EGR cooler having reduced cooling efficiency can be prevented.
[0026]
According to the second aspect of the present invention, when the EGR gas is bypassed, the EGR gas flow path on the EGR cooler side is shut off by the switching valve, so that the blowback of the EGR gas to the EGR cooler can be prevented. According to the third aspect of the present invention, since the driver can quickly grasp the abnormal situation by the notification means, there is an advantage that the maintenance of the EGR cooler can be performed early.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an EGR device according to one embodiment of claims 1 to 3;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Intake passage 3 Engine 5 Intake manifold 7 Exhaust passage 9 Exhaust manifold 11 Silencer 13 EGR pipe 15 EGR valve 17 ECU
19 EGR cooler 21 Inlet pipe 23 Outlet pipe 25 Bypass passage 27, 29, 31 Switching valve 33 Pressure gauge 35 Thermometer 37 Alarm buzzer 39 Alarm lamp 41 EGR device

Claims (3)

ディーゼルエンジンの吸気系と排気系との間に接続されたＥＧＲパイプと、当該ＥＧＲパイプに装着されたＥＧＲクーラーと、ＥＧＲクーラーよりＥＧＲガス上流側のＥＧＲパイプに装着されたＥＧＲバルブと、運転状況検出手段の検出値を基に、予め設定したＥＧＲ領域で上記ＥＧＲバルブを開放制御する制御手段とを備えたディーゼルエンジンのＥＧＲ装置に於て、
上記ＥＧＲクーラーよりＥＧＲガス上流側とＥＧＲガス下流側のＥＧＲパイプとの間、または、ＥＧＲクーラーよりＥＧＲガス上流側のＥＧＲパイプとエンジン吸気系との間にＥＧＲクーラーをバイパスするバイパス通路を接続し、当該バイパス通路と、ＥＧＲガス上流側のＥＧＲパイプとの分岐部に切換えバルブを装着すると共に、当該切換えバルブのＥＧＲガス上流側に圧力計を装着し、ＥＧＲクーラーの冷媒導出口に温度計を装着し、
前記制御手段は、圧力計と温度計のいずれか一方の検出値が予め設定された設定値に達したとき、上記切換えバルブを開閉制御してＥＧＲガスをバイパス通路へバイパスさせることを特徴とするディーゼルエンジンのＥＧＲ装置。An EGR pipe connected between the intake system and the exhaust system of the diesel engine, an EGR cooler mounted on the EGR pipe, an EGR valve mounted on the EGR pipe upstream of the EGR cooler with EGR gas, Control means for controlling the opening of the EGR valve in a preset EGR range based on the detection value of the detection means.
A bypass passage for bypassing the EGR cooler is connected between the EGR gas upstream of the EGR cooler and the EGR pipe downstream of the EGR gas, or between the EGR pipe upstream of the EGR cooler and the engine intake system. A switching valve is attached to the branch between the bypass passage and the EGR pipe on the upstream side of the EGR gas, and a pressure gauge is attached on the upstream side of the EGR gas of the switching valve, and a thermometer is provided at a refrigerant outlet of the EGR cooler. Put on,
When one of the detected values of the pressure gauge and the thermometer reaches a preset value, the control means controls opening and closing of the switching valve to bypass the EGR gas to the bypass passage. EGR equipment for diesel engines. バイパス通路と、ＥＧＲクーラーよりＥＧＲガス下流側のＥＧＲパイプとの合流部に切換えバルブを装着し、制御手段は、圧力計と温度計のいずれか一方の検出値が予め設定された設定値に達したとき、当該切換えバルブを開閉制御して、ＥＧＲクーラー側のＥＧＲガス流路を閉鎖することを特徴とする請求項１記載のディーゼルエンジンのＥＧＲ装置。A switching valve is mounted at the junction of the bypass passage and the EGR pipe downstream of the EGR cooler from the EGR gas, and the control means determines that the detected value of one of the pressure gauge and the thermometer reaches a preset value. 2. The EGR device for a diesel engine according to claim 1, wherein the switching valve is controlled to open and close to close the EGR gas passage on the EGR cooler side. 圧力計と温度計の検出値の異常状況を報知する報知手段を備え、制御手段は、圧力計または温度計の検出値が予め設定された設定値に達したとき、当該報知手段を作動させることを特徴とする請求項１または請求項２記載のディーゼルエンジンのＥＧＲ装置。A notifying unit for notifying an abnormal state of the detected value of the pressure gauge and the thermometer is provided, and the control unit activates the notifying unit when the detected value of the pressure gauge or the thermometer reaches a preset value. The EGR device for a diesel engine according to claim 1 or 2, wherein:
JP2003148183A 2003-05-26 2003-05-26 EGR device for diesel engine Expired - Fee Related JP4203355B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2003148183A JP4203355B2 (en) 2003-05-26 2003-05-26 EGR device for diesel engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2003148183A JP4203355B2 (en) 2003-05-26 2003-05-26 EGR device for diesel engine

Publications (2)

Publication Number Publication Date
JP2004346918A true JP2004346918A (en) 2004-12-09
JP4203355B2 JP4203355B2 (en) 2008-12-24

Family

ID=33534498

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2003148183A Expired - Fee Related JP4203355B2 (en) 2003-05-26 2003-05-26 EGR device for diesel engine

Country Status (1)

Country Link
JP (1) JP4203355B2 (en)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007020846A1 (en) * 2005-08-17 2007-02-22 Hino Motors, Ltd. Exhaust gas recirculation device of engine
FR2905735A1 (en) * 2006-09-12 2008-03-14 Renault Sas DEVICE FOR IMPROVING THE OPERATION OF A SUPERIOR ENGINE WITH AN EXHAUST GAS RECIRCULATION CIRCUIT
FR2909719A1 (en) * 2006-12-12 2008-06-13 Renault Sas Internal combustion engine e.g. oil engine, for motor vehicle, has regulation unit for regulating temperature of recycled gas by proportional action on valves based on set point temperature of recycled exhaust gas
FR2917126A1 (en) * 2007-06-08 2008-12-12 Renault Sas Exhaust gas recirculation system diagnosing and controlling system for e.g. diesel engine, has regulation block regulating temperature of recycled gas via non linear action on bypass valve based on set point temperature of exhaust gas
WO2009037407A1 (en) * 2007-09-20 2009-03-26 Renault S.A.S. Method for diagnosing the exchanger bypass flap in an exhaust gas recirculation circuit
JP2009091917A (en) * 2007-10-04 2009-04-30 Toyota Motor Corp Internal combustion engine control device
JP2009103089A (en) * 2007-10-25 2009-05-14 Nissan Motor Co Ltd Exhaust emission refluxing device of internal combustion engine
JP2009103132A (en) * 2007-10-22 2009-05-14 Robert Bosch Gmbh Operating method of internal combustion engine
JP2009270476A (en) * 2008-05-07 2009-11-19 Denso Corp Egr flow control device and egr flow control system
JP2010090773A (en) * 2008-10-07 2010-04-22 Toyota Industries Corp Control device for engine
JP2010180818A (en) * 2009-02-06 2010-08-19 Toyota Motor Corp Exhaust recirculating device for internal combustion engine
JP2010190111A (en) * 2009-02-18 2010-09-02 Nissan Motor Co Ltd Exhaust gas recirculation device for internal combustion engine
JP2010255602A (en) * 2009-04-28 2010-11-11 Toyota Motor Corp Control device for vehicle
US8146573B2 (en) 2007-02-08 2012-04-03 Yanmar Co., Ltd. EGR device for engine
US8342015B2 (en) 2007-09-20 2013-01-01 Renault S.A.S. Method for diagnosing the exchanger bypass flap in an exhaust gas recirculation circuit
KR101905554B1 (en) * 2012-12-13 2018-11-21 현대자동차 주식회사 Exhaust recirculation system and control method for the same

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007051566A (en) * 2005-08-17 2007-03-01 Hino Motors Ltd Exhaust gas recirculation system for engine
WO2007020846A1 (en) * 2005-08-17 2007-02-22 Hino Motors, Ltd. Exhaust gas recirculation device of engine
FR2905735A1 (en) * 2006-09-12 2008-03-14 Renault Sas DEVICE FOR IMPROVING THE OPERATION OF A SUPERIOR ENGINE WITH AN EXHAUST GAS RECIRCULATION CIRCUIT
WO2008031959A1 (en) * 2006-09-12 2008-03-20 Renault S.A.S. Device improving the operation of a supercharged engine with an exhaust gas recirculation circuit
FR2909719A1 (en) * 2006-12-12 2008-06-13 Renault Sas Internal combustion engine e.g. oil engine, for motor vehicle, has regulation unit for regulating temperature of recycled gas by proportional action on valves based on set point temperature of recycled exhaust gas
US8146573B2 (en) 2007-02-08 2012-04-03 Yanmar Co., Ltd. EGR device for engine
KR101272960B1 (en) * 2007-02-08 2013-06-25 얀마 가부시키가이샤 Egr device for engine
FR2917126A1 (en) * 2007-06-08 2008-12-12 Renault Sas Exhaust gas recirculation system diagnosing and controlling system for e.g. diesel engine, has regulation block regulating temperature of recycled gas via non linear action on bypass valve based on set point temperature of exhaust gas
WO2009037407A1 (en) * 2007-09-20 2009-03-26 Renault S.A.S. Method for diagnosing the exchanger bypass flap in an exhaust gas recirculation circuit
FR2921425A1 (en) * 2007-09-20 2009-03-27 Renault Sas METHOD FOR DIAGNOSING THE EXCHANGER DERIVATION FLAP IN AN EXHAUST GAS RECIRCULATION CIRCUIT
US8342015B2 (en) 2007-09-20 2013-01-01 Renault S.A.S. Method for diagnosing the exchanger bypass flap in an exhaust gas recirculation circuit
JP2009091917A (en) * 2007-10-04 2009-04-30 Toyota Motor Corp Internal combustion engine control device
JP2009103132A (en) * 2007-10-22 2009-05-14 Robert Bosch Gmbh Operating method of internal combustion engine
JP2009103089A (en) * 2007-10-25 2009-05-14 Nissan Motor Co Ltd Exhaust emission refluxing device of internal combustion engine
JP2009270476A (en) * 2008-05-07 2009-11-19 Denso Corp Egr flow control device and egr flow control system
JP2010090773A (en) * 2008-10-07 2010-04-22 Toyota Industries Corp Control device for engine
JP2010180818A (en) * 2009-02-06 2010-08-19 Toyota Motor Corp Exhaust recirculating device for internal combustion engine
JP2010190111A (en) * 2009-02-18 2010-09-02 Nissan Motor Co Ltd Exhaust gas recirculation device for internal combustion engine
JP2010255602A (en) * 2009-04-28 2010-11-11 Toyota Motor Corp Control device for vehicle
KR101905554B1 (en) * 2012-12-13 2018-11-21 현대자동차 주식회사 Exhaust recirculation system and control method for the same

Also Published As

Publication number Publication date
JP4203355B2 (en) 2008-12-24

Similar Documents

Publication Publication Date Title
JP4203355B2 (en) EGR device for diesel engine
JP4333725B2 (en) Exhaust gas recirculation device for internal combustion engine
CN101490399B (en) Exhaust gas recirculation system of internal combustion engine
KR101272960B1 (en) Egr device for engine
JP5708584B2 (en) Control device for internal combustion engine
JP2006336547A (en) Egr device
JP2010048107A (en) Exhaust gas recirculation device for diesel engine
JP4802992B2 (en) Exhaust gas recirculation device for internal combustion engine
JP2012122339A (en) Method and device for determining operability of egr valve
US20140251268A1 (en) Exhaust gas purification system for internal combustion engine
JP4126730B2 (en) Exhaust gas recirculation device
JP2008138638A (en) Exhaust recirculating device of internal combustion engine
CN113958417B (en) High-temperature protection control method and device for EGR check valve and storage medium
KR101756022B1 (en) Apparatus and method for regenerating diesel particular matter filter
JP2016180364A (en) Egr system for internal combustion engine, internal combustion engine and egr control method for internal combustion engine
JP2007046599A (en) Exhaust manifold assembly body for internal combustion engine and exhaust gas controller and control method for internal combustion engine equipped with assembly body
JP4969225B2 (en) Engine exhaust system with DPF device
JP3822761B2 (en) Exhaust purification device
WO2013011768A1 (en) Engine cooling circuit
JP2012082723A (en) Cooling device of internal combustion engine
JP2005002975A (en) Exhaust purification device for engine
JP2005127137A (en) Egr system of engine
JP2004324417A (en) Exhaust gas recirculation system
JP2007146774A (en) Egr system
JP2004211635A (en) Exhaust emission control device and exhaust emission control method for engine

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20060330

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20080513

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20080527

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20080728

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20081007

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20081010

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20111017

Year of fee payment: 3

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20111017

Year of fee payment: 3

S533 Written request for registration of change of name

Free format text: JAPANESE INTERMEDIATE CODE: R313533

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20111017

Year of fee payment: 3

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20141017

Year of fee payment: 6

LAPS Cancellation because of no payment of annual fees