JP4221931B2

JP4221931B2 - Exhaust heat exchanger

Info

Publication number: JP4221931B2
Application number: JP2002007333A
Authority: JP
Inventors: 明宏前田; 孝幸林
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2001-07-10
Filing date: 2002-01-16
Publication date: 2009-02-12
Anticipated expiration: 2022-01-16
Also published as: JP2003090693A

Description

【０００１】
【発明の属する技術分野】
本発明は、燃焼により発生した排気と水などの冷却流体との間で熱交換を行う排気熱交換器に関するもので、ＥＧＲ（排気再循環装置）用の排気を冷却する排気熱交換器（以下、ＥＧＲガス熱交換器と呼ぶ。）に関する。
【０００２】
【従来の技術】
従来、ＥＧＲガス熱交換器としては、図５に示すように、タンク１０２の内部に、積層された複数本の排気チューブ１０１が納められた構造のものが知られている。タンク１０２はコアプレート１０３によって閉塞されており、排気チューブ１０１はコアプレート１０３に固着される。タンク１０２には冷却水入口管１０４と冷却水出口管１０５とが接続され、タンク１０２内部には冷却水が流入し排気チューブ１０１を通過する排気ガスと熱交換する。
【０００３】
【発明が解決しようとする課題】
ところで、本発明者らは、排気チューブ４段のＥＧＲガス熱交換器における冷却水流れの可視化観察を行った。その結果、次に示す知見が得られた。
【０００４】
すなわち、排気チューブ１０１の長手方向に対して交差するように冷却水入口管１０４がタンク１０２に接続された構造であると、排気チューブ１０１と排気チューブ１０１との間では、図６に示すように、冷却水入口管１０４から流入した冷却水は主に約９０°曲がるように冷却水出口管１０５へと向けて流れる（冷却水流れＡ）とともに、冷却水の一部は冷却水入口管１０４と対向するタンク１０２の内壁面１０２ａに衝突し、最上段側もしくは最下段側（排気チューブ１０１が積層される方向において最外側）の排気チューブ１０１側へと流れる（冷却水流れＢ）。
【０００５】
一方、最外側に配される排気チューブ１０１と、タンク１０２の内壁面との間では、冷却水入口管１０４から流入した冷却水流れＡと、排気チューブ１０１と排気チューブ１０１の間からまわりこんだ冷却水流れＢとが干渉し、排気チューブ１０１とコアプレート１０３との接続部位である排気チューブ１０１の根付部１０１ａ近傍で冷却水流れの淀みが生じやすいことが明らかとなった。
【０００６】
排気流れ上流側のチューブ根付部１０１ａ近傍において冷却水の淀みが生じると、この淀みが生じた部分で冷却水が沸騰し、熱交換効率が低下してしまう可能性があった（図７）。
【０００７】
そこで、本発明は、排気ガスを冷却水で冷却するＥＧＲガスクーラーにおいて、冷却水の淀みの発生を抑制し、冷却水の沸騰を防止することを目的とする。
【０００８】
【課題を解決するための手段】
本発明は、上記目的を達成するために以下の技術的手段を採用する。請求項１記載の発明では、内燃機関の排気ガスが通過する断面扁平形状を有しており、断面長手方向が互いに対向するように積層される複数の排気通路と、これらの排気通路を内部に納めたタンクと、このタンクの内部に形成され、排気通路の周囲を冷却水が流れる冷却水通路と、排気通路の積層方向および排気通路の長手方向に対して交差する向きでタンクに接続され、冷却水通路のうち各排気通路の間に形成される排気通路間冷却水通路に向けて冷却水を流入させる冷却水入口管と、冷却水通路から冷却水を流出させる冷却水出口管と、冷却水通路に設けられる案内手段とを備える排気熱交換器であって、案内手段は、冷却水入口管から冷却水通路のうち積層方向の最外側に配される排気通路とタンクの内壁面との間に形成される最外側冷却水通路へ冷却水入口管側のタンク内壁面に沿って流れる冷却水を排気通路の上流側へと導く入口管側案内部と、排気通路間冷却水通路を通過して冷却水入口管と対面するタンクの内壁面と衝突した後に最外側冷却水通路へ入口管側案内部によって導かれる冷却水流れと対向するように流れる冷却水を排気通路の上流側へと導く内壁面側案内部とを備え、入口管側案内部と内壁面側案内部との間には間隙が形成されていることを特徴とする。
【０００９】
これにより、タンクの内壁面と衝突した冷却水流れは案内手段によって前記排気通路の上流側と接触する部位へと案内される。そのため、排気ガスの温度の高い排気通路の上流側における冷却水の淀みの発生を抑制でき、冷却水の沸騰を抑制することができる。
【００１０】
ところで、排気通路の積層方向および排気通路の長手方向に対して交差する方向に冷却水が流入するよう冷却水流入管が設けられている排気熱交換器では、特に、排気通路どうしの間を通過した冷却水流れが冷却水入口管から流入する冷却水流れと干渉しやすく、大きな冷却水の淀みが生じやすい。そのため、特に、排気通路の積層方向および排気通路の長手方向に対して交差する向きで冷却水通路に冷却水が流入する排気熱交換器において、より顕著に熱交換効率の低下を抑制できる。
【００１１】
また、請求項２に記載したように、案内手段を前記排気通路の外壁面から前記冷却水通路へと突出するよう形成すると、案内手段を冷却水通路の補強部とすることができ、冷却水通路の耐圧性も高めることができる。
さらに、請求項３に記載の発明によれば、排気通路が断面偏平形状を有する排気熱交換器において、冷却水をより確実に排気通路の上流側へと導くことができる。
【００１２】
また、請求項４の発明では、内燃機関の排気ガスが通過する断面扁平形状を有しており、断面長手方向が互いに対向するように積層される複数の排気チューブと、これらの排気チューブを内部に納めたタンクと、このタンクの内部に形成され、排気通路の周囲を冷却水が流れる冷却水通路と、排気チューブの端部と連結し、複数の排気チューブへと排気ガスを分配する、または複数の排気チューブを通過した排気ガスを集めるボンネットと、排気チューブの端部近傍に取り付けられ、ボンネットと冷却水通路とを区画するコアプレートと、排気通路の積層方向および排気通路の長手方向に対して交差する向きでタンクに接続され、冷却水通路のうち各排気チューブの間に形成される排気通路間冷却水通路に向けて冷却水を流入させる冷却水入口管と、冷却水通路から冷却水を流出させる冷却水出口管と、冷却水通路に設けられる案内手段とを備える排気熱交換器であって、案内手段は、冷却水入口管から冷却水通路のうち積層方向の最外側に配される排気通路とタンクの内壁面との間に形成される最外側冷却水通路へ冷却水入口管側のタンクの内壁面に沿って流れる冷却水を排気チューブの上流側端部がコアプレートに取り付けられるチューブ根付部近傍に導く入口管側案内部と、排気通路間冷却水通路を通過して冷却水入口管と対面するタンクの内壁面と衝突した後に最外側冷却水通路へ入口管側案内部によって導かれる冷却水流れと対向するように流れる冷却水をチューブ根付部近傍に導く内壁面側案内部とを備え、入口管側案内部と内壁面側案内部との間には間隙が形成されていることを特徴とする。
【００１３】
これにより、タンクの内壁面と衝突した冷却水流れは案内手段によって、排気チューブの根付部近傍へと案内される。そのため、温度の高い排気ガスが通過する排気チューブの根付部近傍において冷却水の淀みの発生を抑制でき、冷却水の局所的な沸騰を抑制することができる。
【００１４】
また、請求項７に記載した発明によれば、請求項３と同様の効果を得ることができる。請求項８に記載した発明によれば、各排気通路の間に形成される冷却水の流路と、最外側に配される排気通路とタンクの内壁面との間に形成される冷却水の流路とは反射防止手段によってそれぞれ区画されるため、各排気通路の間を通過する冷却水がタンクの内壁面に衝突し、最外側に配される排気通路とタンクの内壁面との間の冷却水の流路へと回り込むことを防止することができる。そのため、排気通路上流側における冷却水の回り込みによる淀みの発生を抑えることができ、局所的な沸騰の発生を抑制できる。
【００１５】
【発明の実施の形態】
以下、本発明の実施形態は、本発明に係る排気熱交換装置をディーゼルエンジン（内燃機関）用のＥＧＲガス冷却装置に適用したものであり、図１は本実施形態に係る排気熱交換器（以下、ＥＧＲガス熱交換器と呼ぶ。）１００を用いたＥＧＲ（排気再循環装置）の模式図である。図１中、２００はディーゼルエンジン（以下、エンジンと略す。）であり、２１０はエンジン２００から排出される排気の一部をエンジンの吸気側に貫流させる排気再循環管である。
【００１６】
２２０は排気再循環管２１０の排気流れ途中に配設されて、エンジン２００の稼動状態に応じてＥＧＲガス量を調節する周知のＥＧＲバルブであり、ＥＧＲガス熱交換器１００は、エンジン２００の排気側とＥＧＲバルブ２２０との間に配設されてＥＧＲガスとエンジン冷却水（以下、冷却水と略す。）との間で熱交換を行い、ＥＧＲガスを冷却する。
【００１７】
続いて、ＥＧＲガス熱交換器１００の構造について述べる。なお、従来技術とほぼ同様の構造を有する構成には同一の符号を付した。
【００１８】
１０１は内部を排気が流れる排気チューブ（請求項における排気通路）であり、扁平な略矩形の断面形状を有する。排気チューブ１０１は、図示しない一対のプレートが対向接合されることによって構成されている。排気チューブ１０１の内部にはインナーフィン１０１ｂ（排気チューブ１０１内を細流路に区画するよう排気チューブ１０１の幅方向において折曲成形されている）が配されている。
【００１９】
１０２は筒形状のタンクであり、その断面は略矩形形状を有する。排気チューブ１０１は互いに平行となるように積層されており、排気チューブ１０１の長手方向とタンク１０２の長手方向とが一致するように、タンク１０２の内部に納められており、熱交換コアを構成する。
【００２０】
タンク１０２の両端はコアプレート１０３によって閉塞されており、タンク１０２内部に納められた各排気チューブ１０１の両端部がコアプレート１０３に捜通され、支持されている。
【００２１】
排気チューブ１０１の上流側端部である根付部１０１ａ近傍には冷却水入口管１０４が接続されており、この冷却水入口管１０４を介して冷却水はタンク１０２内部に流入する。冷却水入口管１０４は、排気チューブ１０１の積層方向と交差する向きでタンク１０２に接続されており、積層された各排気チューブ１０１間の間隙に向けて冷却水を流入させる。タンク１０２の他端近傍となる位置には、冷却水をタンク１０２外部へと流出させる冷却水出口管１０５が接続されており、タンク１０２の内部は冷却水通路となっている。なお、タンク１０２の内部において、冷却水の主流は、排気チューブ１０１を通過する排気流れとほぼ同じ方向に流れている。
【００２２】
熱交換コア１１０と反対側となる、タンク１０２の長手方向両端部にはボンネット１０６、１０７が接続されており、ボンネット１０６，１０７の周囲を覆うようにコアプレート１０３は熱交換コア１１０とは反対側に折り曲げられ、接合される。冷却水入口管１０４側に配されるボンネット１０６端部には、排気ガスをボンネット１０６に導入する排気入口１０６ａが形成されており、冷却水出口管１０５側に配されるボンネット１０７端部には、排気ガスをボンネット１０７から外部へと導出する排気出口１０７ａが形成される。ボンネット１０６、１０７は熱交換コア１１０側となるにつれて徐々に流路面積が増大するような略四角錐形状を有しており、各排気チューブ１１０への排気ガスの分配を良好なものとしている。
【００２３】
以下、本発明の要部について説明する。排気チューブ１０１の排気入口１０６ａ側となる位置には、外方に突出するよう一対のリブ１０８（案内手段）が打出成形されている。リブ１０８ａ、ｂは図２（ａ）に示すように、排気チューブ１０１の幅方向（断面長手方向）の端部から冷却水通路の幅方向の中央部近傍まで、排気チューブ１０１およびタンク１０２の長手方向（タンク１０２において冷却水の主流が流れる向き）と交差する向きに伸びる長円形状を有しており、リブ１０８ａとリブ１０８ｂの間には冷却水が通過可能な間隙が形成されている。
【００２４】
なお、対向する排気チューブ１０１の内壁面に形成されたリブ１０８ａ，ｂどうしはそれぞれ当接しており、排気チューブ１０１の積層方向において最外側となる排気チューブ１０１のリブ１０８ａ、ｂと対向するタンク１０２の内壁面にはリブと当接する突出部１０９が形成されている。なお、突出部１０９もリブ１０８ａ，ｂと同様の形状を有する。
【００２５】
このような構成を有するＥＧＲガス熱交換器１００において、排気入口１０６ａから導入された排気ガスはボンネット１０６を通過し、各排気チューブ１０１内を通過する。排気チューブ１０１の周囲を流れる冷却水によって冷却された排気ガスはボンネット１０７を通過し、排気出口１０７ａから導出される。
【００２６】
冷却水は、冷却水入口管１０４を介してタンク１０２の内部に流入し、冷却水は積層された各排気チューブ１０１の間、および最外側の排気チューブ１０１とタンク１０２の内壁面との間を通過する。この際、冷却水はタンク１０２の長手方向とほぼ直交する向きでタンク１０２内部に流入するため、冷却水入口管１０４と対向するタンク１０２の内壁面１０２ａに衝突し、積層方向において最外側となる排気チューブ１０１側に向けて（図２（ｂ）中上下方向）分流する。分流した冷却水流れは最外側に配される排気チューブ１０１とタンク１０２の内壁面との間の空間へとまわりこみ、リブ１０８ｂに沿って排気チューブ１０１の根付部１０１ａ（上流側端部）近傍を強制的に流れる（図２中矢印Ｃで示す）。リブ１０８ｂに沿って流れる冷却水流れＣは、リブ１０８ａ、ｂ間の間隙において冷却水入口管１０４から流入した冷却水流れＡと合流し、冷却水出口管１０５側へと流れる。
【００２７】
本実施の形態によれば、タンク１０２の内壁面１０２ａに衝突した冷却水流れＣはリブ１０８ｂに沿って流れるため、排気チューブ１０１の上流側を通過させることができる。そのため、排気ガスの上流側と接触する部位において冷却水の淀みの発生を抑え、冷却水の局所的な沸騰を抑制することができる。
【００２８】
また、本実施の形態において、対向する排気チューブ１０１の外壁面に形成されたリブ１０８ａ、ｂどうし、もしくはリブ１０８ａ、ｂと突出部１０９とは当接しており、冷却水通路としてのタンク１０２、および排気チューブ１０１の耐圧強度を高めることができる。さらに、ＥＧＲガス熱交換器１００を製造時、排気チューブ１０１を積層してろう付けを行うにあたって、タンク１０２内部に配される排気チューブ１０１およびインナーフィン１０１ｂに対して適正な荷重を加えることができ、ろう付け不良を防止することができる。また、各排気チューブ１０１間の間隔、およびタンク１０２の内壁面と排気チューブ１０１と間の間隔を一定に保つことができる。
【００２９】
また、排気チューブ１０１にリブ１０８ａ、ｂが形成されるので、タンク１０２の内壁面１０２ａに衝突して排気チューブ１０１とタンク１０２との間に流入する冷却水流れも、リブ１０８ｂに沿って排気チューブ１０１の上流側へと流すことができる。
【００３０】
なお、上述した実施の形態では、排気チューブ１０１の外壁面に一対のリブ１０８ａ、ｂを打出成形した形態についてのべたが、リブの成形方法は特に限定されるものではなく、排気チューブとは別体としてもよい。また、リブの形状は、冷却水入口管に対向する内壁面に衝突し、まわりこんだ冷却水流れが、排気チューブ上流側に流れるような形状であればよい。
【００３１】
また、タンクの内壁面１０２ａに衝突した冷却水流れが特に回り込みやすい最外側に配される排気チューブのみにリブを形成してもよい。
【００３２】
（他の実施の形態）
上述した実施の形態では、タンク１０２の内壁面１０２ａに衝突し、排気チューブ１０１とタンク１０２の内壁面との間の空間へとまわりこんだ冷却水流れを、排気チューブ１０１の上流側へと導くリブ１０８ａ、ｂを形成した実施の形態について述べたが、以下に述べるように、冷却水流れの回り込みを防止する反射防止板を設けた構造としてもよい。なお、上述した実施の形態とほぼ同様の構造を有する構成については同一の符号を付し、説明は省略する。
【００３３】
図３は他の実施形態におけるガスクーラを示す図であり、図４は図３（ｂ）のＤ−Ｄ線断面図である。
【００３４】
図４に示すように、タンク１０２は対向接合された一対のプレートからなり、排気チューブ１０１は対向接合された一対のプレートからなる。排気チューブ１０１の内部にはインナーフィン１０１ａが配されており、インナーフィン１０１ａには渦流を発生させるルーバ１０１ｂが形成されている。
【００３５】
図３（ａ）、図４に示すように、冷却水入口管１０４と対向するタンク１０の内壁面１０２ａと排気チューブ１０１との間には反射防止板１１０（請求項における反射防止手段）が設けられている。板材を折曲成形した反射防止板１１０は、各折曲部１１０ａが排気チューブ１０１に当接するように配される。積層された各排気チューブ１０１間に形成される冷却水の流路１１１、および最外側の排気チューブ１０１とタンク１０２の内壁面との間に形成される冷却水の流路１１２は折曲部１１０ａによってそれぞれ区画される。
【００３６】
冷却水入口管１０４を介して流入した冷却水は、図３（ａ）、および図４中矢印Ｅで示すように、冷却水入口管１０４から流入した冷却水は各流路１１１、１１２へと流れ、流路１１１を通過する冷却水は流路１１２にまわり込むことなく、冷却水出口管１０５側へと流れる。図５〜７に示した構造の排気熱交換器のように、排気チューブ１０１の上流側においてタンク１０２の内壁面１０２ａに衝突してまわり込んだ冷却水と、冷却水入口管１０４からの冷却水とが干渉して冷却水の淀みが発生することがなく、冷却水の局所的な沸騰を防止することができる。
【００３７】
なお、上述した実施の形態では、反射防止板１１０として折曲成形した板材を用いた形態について述べたが、積層された各排気チューブ１０１間に形成される流路１１１、および最外側の排気チューブ１０１とタンク１０２の内壁面との間に形成される冷却水の流路１１２をそれぞれ区画する構造を有するものであればよく、上述した実施の形態と同様の作用・効果を奏することはもちろんである。
【００３８】
また、上述した実施の形態では反射防止板１１０と排気チューブ１０１とを当接した構造としたが、冷却水流路１１１を通過する冷却水が実質的に冷却水流路１１２へとまわり込まない構造であればよく、冷却水流路１１２への冷却水のまわり込みがない程度の間隙が反射防止板１１０と排気チューブ１０１との間に形成されていたとしてもよい。
【図面の簡単な説明】
【図１】本発明の実施形態おけるガスクーラを用いたＥＧＲガス冷却装置の模式図である。
【図２】本発明の実施形態におけるガスクーラを示す図であり、図２（ａ）は側方から見た一部破断図であり、図２（ｂ）は上面から見た一部破断図である。
【図３】本発明の他の実施形態におけるガスクーラを示す図であり、図３（ａ）は側方から見た一部破断図であり、図３（ｂ）は上面から見た一部破断図である。
【図４】図３（ａ）のＤ−Ｄ線断面図である。
【図５】従来技術におけるガスクーラを側方からみた一部破断図である。
【図６】従来技術のガスクーラのチューブとチューブとの間の冷却水通路における冷却水の流れを示す図である。
【図７】従来技術のガスクーラの最外側のチューブとタンク内壁面との間の冷却水通路における冷却水の流れを示す図である。
【符号の説明】
１００…ガスクーラ、
１０１…排気チューブ、
１０２…タンク、
１０３…コアプレート、
１０４…冷却水入口管、
１０５…冷却水出口管、
１０７…ボンネット、
１０８…リブ（案内手段）。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust heat exchanger that performs heat exchange between an exhaust gas generated by combustion and a cooling fluid such as water, and an exhaust heat exchanger (hereinafter referred to as an exhaust heat exchanger) that cools exhaust gas for an EGR (exhaust gas recirculation device). , Referred to as an EGR gas heat exchanger).
[0002]
[Prior art]
Conventionally, as an EGR gas heat exchanger, as shown in FIG. 5, a structure in which a plurality of stacked exhaust tubes 101 are accommodated in a tank 102 is known. The tank 102 is closed by the core plate 103, and the exhaust tube 101 is fixed to the core plate 103. A cooling water inlet pipe 104 and a cooling water outlet pipe 105 are connected to the tank 102, and cooling water flows into the tank 102 and exchanges heat with the exhaust gas passing through the exhaust tube 101.
[0003]
[Problems to be solved by the invention]
By the way, the present inventors performed visualization observation of the cooling water flow in the EGR gas heat exchanger having four stages of exhaust tubes. As a result, the following knowledge was obtained.
[0004]
That is, when the cooling water inlet pipe 104 is connected to the tank 102 so as to intersect with the longitudinal direction of the exhaust tube 101, as shown in FIG. The cooling water flowing in from the cooling water inlet pipe 104 mainly flows toward the cooling water outlet pipe 105 so as to bend about 90 ° (cooling water flow A), and a part of the cooling water is connected to the cooling water inlet pipe 104. It collides with the inner wall surface 102a of the opposing tank 102 and flows to the exhaust tube 101 side on the uppermost side or the lowermost side (outermost side in the direction in which the exhaust tubes 101 are stacked) (cooling water flow B).
[0005]
On the other hand, between the exhaust tube 101 disposed on the outermost side and the inner wall surface of the tank 102, the cooling water flow A that has flowed from the cooling water inlet pipe 104 and the space between the exhaust tube 101 and the exhaust tube 101 wrap around. It became clear that the cooling water flow B interferes and the stagnation of the cooling water flow tends to occur in the vicinity of the root portion 101 a of the exhaust tube 101, which is a connection portion between the exhaust tube 101 and the core plate 103.
[0006]
If stagnation of the cooling water occurs in the vicinity of the tube root portion 101a on the upstream side of the exhaust flow, the cooling water may boil at the portion where the stagnation occurs and the heat exchange efficiency may be reduced (FIG. 7).
[0007]
Therefore, an object of the present invention is to suppress generation of stagnation of cooling water and prevent boiling of cooling water in an EGR gas cooler that cools exhaust gas with cooling water.
[0008]
[Means for Solving the Problems]
The present invention employs the following technical means to achieve the above object. In the first aspect of the present invention, which have a cross section flattened shape exhaust gas you pass the inner combustion engine, a plurality of exhaust passages which are laminated so that cross-sectional longitudinal direction to face each other, these exhaust passages Is formed in the tank, the cooling water passage through which the cooling water flows around the exhaust passage, and the tank in a direction intersecting the stacking direction of the exhaust passage and the longitudinal direction of the exhaust passage. A cooling water inlet pipe that allows cooling water to flow toward the cooling water passage between the exhaust passages that is connected and formed between the exhaust passages, and a cooling water outlet pipe that causes the cooling water to flow out of the cooling water passage And a guide means provided in the cooling water passage, wherein the guide means is an inner part of the tank and the exhaust passage arranged on the outermost side in the stacking direction of the cooling water passage from the cooling water inlet pipe. The outermost side formed between the wall An inlet pipe side guide for guiding cooling water flowing along the inner wall of the tank on the cooling water inlet pipe side to the rejection water path, and a cooling water inlet pipe passing through the cooling water passage between the exhaust passages. An inner wall-side guide that guides the cooling water flowing to the outermost cooling water passage after facing the inner wall of the tank facing the tank toward the upstream side of the exhaust passage. And a gap is formed between the inlet tube side guide portion and the inner wall surface side guide portion.
[0009]
Thereby, the cooling water flow colliding with the inner wall surface of the tank is guided by the guide means to a portion that contacts the upstream side of the exhaust passage. Therefore, generation | occurrence | production of the stagnation of the cooling water in the upstream of the exhaust passage with high exhaust gas temperature can be suppressed, and boiling of the cooling water can be suppressed.
[0010]
By the way, in the exhaust heat exchanger in which the cooling water inflow pipe is provided so that the cooling water flows in a direction intersecting with the stacking direction of the exhaust passages and the longitudinal direction of the exhaust passages, the exhaust heat passages are particularly passed between the exhaust passages. The cooling water flow easily interferes with the cooling water flow flowing in from the cooling water inlet pipe, and a large stagnation of the cooling water is likely to occur. Therefore, particularly in an exhaust heat exchanger in which cooling water flows into the cooling water passage in a direction intersecting with the stacking direction of the exhaust passage and the longitudinal direction of the exhaust passage, it is possible to suppress the decrease in heat exchange efficiency more remarkably.
[0011]
According to a second aspect of the present invention, when the guide means is formed so as to protrude from the outer wall surface of the exhaust passage to the cooling water passage, the guide means can be a reinforcing portion of the cooling water passage, The pressure resistance of the passage can also be increased.
Furthermore, according to the third aspect of the present invention, in the exhaust heat exchanger in which the exhaust passage has a flat cross section, the cooling water can be more reliably guided to the upstream side of the exhaust passage.
[0012]
According to a fourth aspect of the present invention, the exhaust gas of the internal combustion engine has a flat cross-sectional shape, and a plurality of exhaust tubes stacked so that the longitudinal direction of the cross-sections face each other, and these exhaust tubes are disposed inside And a tank formed in the tank, connected to a cooling water passage through which the cooling water flows around the exhaust passage, and an end of the exhaust tube, and distributes exhaust gas to a plurality of exhaust tubes, or A bonnet that collects exhaust gas that has passed through a plurality of exhaust tubes, a core plate that is attached near the end of the exhaust tube, and divides the bonnet and the cooling water passage, and the stacking direction of the exhaust passage and the longitudinal direction of the exhaust passage The cooling water is introduced into the cooling water passage between the exhaust passages formed between the exhaust tubes in the cooling water passage. An exhaust heat exchanger comprising a pipe, a cooling water outlet pipe for allowing cooling water to flow out from the cooling water passage, and guide means provided in the cooling water passage, wherein the guiding means is connected to the cooling water passage from the cooling water inlet pipe. Among them, the cooling water flowing along the inner wall surface of the tank on the cooling water inlet pipe side is supplied to the outermost cooling water passage formed between the exhaust passage disposed on the outermost side in the stacking direction and the inner wall surface of the tank. The inlet pipe side guide part whose upstream end is led to the vicinity of the tube base attached to the core plate, and the outermost part after colliding with the inner wall surface of the tank passing through the cooling water passage between the exhaust passages and facing the cooling water inlet pipe An inlet wall side guide part and an inner wall side guide part provided with an inner wall side guide part for guiding the cooling water flowing so as to face the cooling water flow guided to the cooling water passage by the inlet pipe side guide part to the vicinity of the tube root part. A gap is formed between And said that you are.
[0013]
Thereby, the cooling water flow colliding with the inner wall surface of the tank is guided by the guiding means to the vicinity of the root portion of the exhaust tube. Therefore, it is possible to suppress the occurrence of stagnation of the cooling water in the vicinity of the root portion of the exhaust tube through which the high-temperature exhaust gas passes, and to suppress local boiling of the cooling water.
[0014]
Further, according to the invention described in claim 7, the same effect as in claim 3 can be obtained. According to the eighth aspect of the present invention, the cooling water flow path formed between the exhaust passages, the cooling water formed between the outermost exhaust passage and the inner wall surface of the tank. Since the flow path is divided by the antireflection means, the cooling water passing between the exhaust passages collides with the inner wall surface of the tank, and between the exhaust passage arranged on the outermost side and the inner wall surface of the tank. It is possible to prevent the cooling water from flowing into the flow path. Therefore, it is possible to suppress the occurrence of stagnation due to the wraparound of the cooling water on the upstream side of the exhaust passage, and to suppress the occurrence of local boiling.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, in the embodiment of the present invention, the exhaust heat exchange device according to the present invention is applied to an EGR gas cooling device for a diesel engine (internal combustion engine), and FIG. 1 shows an exhaust heat exchanger ( Hereinafter, it is referred to as an EGR gas heat exchanger.) FIG. 1 is a schematic diagram of an EGR (exhaust gas recirculation device) using 100. In FIG. 1, reference numeral 200 denotes a diesel engine (hereinafter abbreviated as an engine), and 210 denotes an exhaust gas recirculation pipe that allows a part of the exhaust gas discharged from the engine 200 to flow through to the intake side of the engine.
[0016]
220 is a well-known EGR valve that is disposed in the exhaust gas recirculation pipe 210 and adjusts the amount of EGR gas according to the operating state of the engine 200. The EGR gas heat exchanger 100 is an exhaust gas of the engine 200. Between the EGR valve and the EGR valve 220 to exchange heat between the EGR gas and engine cooling water (hereinafter abbreviated as cooling water) to cool the EGR gas.
[0017]
Next, the structure of the EGR gas heat exchanger 100 will be described. In addition, the same code | symbol was attached | subjected to the structure which has the structure similar to a prior art.
[0018]
Reference numeral 101 denotes an exhaust tube (exhaust passage in the claims) through which exhaust flows, and has a flat , substantially rectangular cross-sectional shape. The exhaust tube 101 is configured by opposingly joining a pair of plates (not shown). Inside the exhaust tube 101, inner fins 101b (bently formed in the width direction of the exhaust tube 101 so as to divide the exhaust tube 101 into narrow flow paths) are arranged.
[0019]
Reference numeral 102 denotes a cylindrical tank having a substantially rectangular cross section. The exhaust tubes 101 are stacked so as to be parallel to each other, and are housed in the tank 102 so that the longitudinal direction of the exhaust tube 101 and the longitudinal direction of the tank 102 coincide with each other, and constitute a heat exchange core. .
[0020]
Both ends of the tank 102 are closed by the core plate 103, and both ends of each exhaust tube 101 housed in the tank 102 are searched for and supported by the core plate 103.
[0021]
A cooling water inlet pipe 104 is connected to the vicinity of the root portion 101 a that is the upstream end of the exhaust tube 101, and the cooling water flows into the tank 102 through the cooling water inlet pipe 104. The cooling water inlet pipe 104 is connected to the tank 102 in a direction intersecting with the stacking direction of the exhaust tubes 101, and allows cooling water to flow into the gaps between the stacked exhaust tubes 101. A cooling water outlet pipe 105 that allows cooling water to flow out of the tank 102 is connected to a position near the other end of the tank 102, and the inside of the tank 102 serves as a cooling water passage. In the tank 102, the main flow of the cooling water flows in substantially the same direction as the exhaust flow passing through the exhaust tube 101.
[0022]
Bonnets 106 and 107 are connected to both ends in the longitudinal direction of the tank 102 on the opposite side to the heat exchange core 110, and the core plate 103 is opposite to the heat exchange core 110 so as to cover the bonnets 106 and 107. Folded to the side and joined. An exhaust inlet 106a for introducing exhaust gas into the bonnet 106 is formed at the end of the bonnet 106 disposed on the cooling water inlet pipe 104 side, and at the end of the bonnet 107 disposed on the cooling water outlet pipe 105 side. An exhaust outlet 107a for leading the exhaust gas from the bonnet 107 to the outside is formed. The bonnets 106 and 107 have a substantially quadrangular pyramid shape in which the flow path area gradually increases toward the heat exchange core 110 side, and the exhaust gas distribution to each exhaust tube 110 is excellent.
[0023]
Hereafter, the principal part of this invention is demonstrated. A pair of ribs 108 (guide means) are stamped and formed at positions on the exhaust tube 101 side of the exhaust tube 101 so as to protrude outward. As shown in FIG. 2 (a), the ribs 108a and 108b extend from the end of the exhaust tube 101 in the width direction (longitudinal direction of the cross section) to the vicinity of the center in the width direction of the cooling water passage. It has an oval shape extending in a direction that intersects the direction (the direction in which the main flow of the cooling water flows in the tank 102), and a gap through which the cooling water can pass is formed between the ribs 108a and 108b.
[0024]
The ribs 108a and 108b formed on the inner wall surfaces of the opposed exhaust tubes 101 are in contact with each other, and the tank 102 facing the ribs 108a and 108b of the exhaust tubes 101 that is the outermost side in the stacking direction of the exhaust tubes 101. A protrusion 109 is formed on the inner wall surface to abut against the rib. The protruding portion 109 has the same shape as the ribs 108a and b.
[0025]
In the EGR gas heat exchanger 100 having such a configuration, the exhaust gas introduced from the exhaust inlet 106 a passes through the bonnet 106 and passes through the exhaust tubes 101. The exhaust gas cooled by the cooling water flowing around the exhaust tube 101 passes through the bonnet 107 and is led out from the exhaust outlet 107a.
[0026]
The cooling water flows into the tank 102 through the cooling water inlet pipe 104, and the cooling water passes between the stacked exhaust tubes 101 and between the outermost exhaust tube 101 and the inner wall surface of the tank 102. pass. At this time, since the cooling water flows into the tank 102 in a direction substantially orthogonal to the longitudinal direction of the tank 102, the cooling water collides with the inner wall surface 102a of the tank 102 facing the cooling water inlet pipe 104 and becomes the outermost side in the stacking direction. The flow is diverted toward the exhaust tube 101 (in the vertical direction in FIG. 2B). The divided coolant flow flows into the space between the exhaust tube 101 disposed on the outermost side and the inner wall surface of the tank 102, and reaches the vicinity of the root portion 101a (upstream end) of the exhaust tube 101 along the rib 108b. Forced flow (indicated by arrow C in FIG. 2). The cooling water flow C flowing along the ribs 108b merges with the cooling water flow A flowing in from the cooling water inlet pipe 104 in the gap between the ribs 108a and 108b, and flows toward the cooling water outlet pipe 105.
[0027]
According to the present embodiment, the cooling water flow C that collides with the inner wall surface 102a of the tank 102 flows along the rib 108b, so that it can pass through the upstream side of the exhaust tube 101. Therefore, generation | occurrence | production of the stagnation of a cooling water can be suppressed in the site | part which contacts the upstream of exhaust gas, and the local boiling of a cooling water can be suppressed.
[0028]
Further, in the present embodiment, the ribs 108a, b formed on the outer wall surface of the opposing exhaust tube 101, or the ribs 108a, b and the protruding portion 109 are in contact with each other, and the tank 102 as a cooling water passage, In addition, the pressure resistance of the exhaust tube 101 can be increased. Further, when the EGR gas heat exchanger 100 is manufactured, when the exhaust tubes 101 are laminated and brazed, an appropriate load can be applied to the exhaust tubes 101 and the inner fins 101b disposed in the tank 102. , Brazing failure can be prevented. Further, the interval between the exhaust tubes 101 and the interval between the inner wall surface of the tank 102 and the exhaust tube 101 can be kept constant.
[0029]
Further, since the ribs 108a and 108b are formed on the exhaust tube 101, the cooling water flow that collides with the inner wall surface 102a of the tank 102 and flows between the exhaust tube 101 and the tank 102 is also exhausted along the rib 108b. 101 can flow to the upstream side.
[0030]
In the above-described embodiment, the form in which the pair of ribs 108a and 108b are formed by stamping on the outer wall surface of the exhaust tube 101 is described, but the rib forming method is not particularly limited, and is different from the exhaust tube. It may be a body. Moreover, the shape of a rib should just be a shape which collides with the inner wall face which opposes a cooling water inlet pipe, and the cooling water flow which flowed around flows into an exhaust tube upstream.
[0031]
Further, the rib may be formed only on the exhaust tube disposed on the outermost side where the coolant flow colliding with the inner wall surface 102a of the tank is particularly easy to circulate.
[0032]
(Other embodiments)
In the above-described embodiment, the cooling water flow that collides with the inner wall surface 102 a of the tank 102 and flows into the space between the exhaust tube 101 and the inner wall surface of the tank 102 is guided to the upstream side of the exhaust tube 101. Although the embodiment in which the ribs 108a and b are formed has been described, as described below, an antireflection plate for preventing the cooling water flow from flowing may be provided. In addition, the same code | symbol is attached | subjected about the structure which has the structure similar to embodiment mentioned above, and description is abbreviate | omitted.
[0033]
FIG. 3 is a view showing a gas cooler in another embodiment, and FIG. 4 is a cross-sectional view taken along the line DD of FIG.
[0034]
As shown in FIG. 4, the tank 102 is composed of a pair of plates that are opposed to each other, and the exhaust tube 101 is composed of a pair of plates that are opposed to each other. Inner fins 101a are arranged inside the exhaust tube 101, and a louver 101b for generating a vortex is formed in the inner fins 101a.
[0035]
As shown in FIGS. 3A and 4, an antireflection plate 110 (antireflection means in claims) is provided between the inner wall surface 102 a of the tank 10 facing the cooling water inlet pipe 104 and the exhaust tube 101. It has been. The antireflection plate 110 formed by bending a plate material is arranged so that each bent portion 110 a comes into contact with the exhaust tube 101. The cooling water flow path 111 formed between the stacked exhaust tubes 101 and the cooling water flow path 112 formed between the outermost exhaust tube 101 and the inner wall surface of the tank 102 are bent portions 110a. Respectively.
[0036]
The cooling water that has flowed in via the cooling water inlet pipe 104 flows into the flow paths 111 and 112 as indicated by an arrow E in FIG. 3A and FIG. The cooling water that flows and passes through the flow path 111 flows toward the cooling water outlet pipe 105 without flowing into the flow path 112. Like the exhaust heat exchanger having the structure shown in FIGS. 5 to 7, the cooling water that collides with the inner wall surface 102 a of the tank 102 on the upstream side of the exhaust tube 101 and the cooling water from the cooling water inlet pipe 104. Stagnation of cooling water does not occur and local boiling of the cooling water can be prevented.
[0037]
In the above-described embodiment, the form using a bent plate as the antireflection plate 110 has been described. However, the flow path 111 formed between the stacked exhaust tubes 101 and the outermost exhaust tube The cooling water flow path 112 formed between the inner wall 101 and the inner wall surface of the tank 102 may be divided so long as it has the same functions and effects as the above-described embodiment. is there.
[0038]
In the above-described embodiment, the antireflection plate 110 and the exhaust tube 101 are in contact with each other, but the cooling water that passes through the cooling water channel 111 does not substantially enter the cooling water channel 112. It suffices that a gap is formed between the antireflection plate 110 and the exhaust tube 101 so that the cooling water does not enter the cooling water flow path 112.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an EGR gas cooling device using a gas cooler in an embodiment of the present invention.
2A and 2B are diagrams showing a gas cooler according to an embodiment of the present invention, in which FIG. 2A is a partially broken view seen from the side, and FIG. 2B is a partially broken view seen from the top surface. is there.
FIG. 3 is a view showing a gas cooler according to another embodiment of the present invention, FIG. 3 (a) is a partially broken view seen from the side, and FIG. 3 (b) is a partially broken view seen from the top surface. FIG.
4 is a cross-sectional view taken along the line DD of FIG.
FIG. 5 is a partially cutaway view of a gas cooler in the prior art as viewed from the side.
FIG. 6 is a view showing a flow of cooling water in a cooling water passage between tubes of a conventional gas cooler.
FIG. 7 is a view showing a flow of cooling water in a cooling water passage between an outermost tube of a conventional gas cooler and an inner wall surface of a tank.
[Explanation of symbols]
100 ... gas cooler,
101 ... exhaust tube,
102 ... tank,
103 ... core plate,
104 ... cooling water inlet pipe,
105 ... cooling water outlet pipe,
107 ... bonnet,
108: Ribs (guide means).

Claims

And have a cross section flattened shape exhaust gas you pass the inner combustion engine, a plurality of exhaust passages which are laminated so that cross-sectional longitudinal direction to face each other,
A tank that houses these exhaust passages,
A cooling water passage formed inside the tank, through which cooling water flows around the exhaust passage;
Which is connected to the tank in a direction crossing the longitudinal direction of the stacking direction and the exhaust passage in the exhaust passage, toward the cooling water passage between an exhaust passage formed between the respective exhaust passages of the cooling water passage a cooling water inlet pipe for flowing coolant Te,
A cooling water outlet pipe for flowing cooling water out of the cooling water passage;
And an exhaust heat exchanger and a guide means that is provided in the cooling water passage,
The guide means moves the cooling water from the cooling water inlet pipe to the outermost cooling water passage formed between the exhaust passage disposed in the outermost layer in the stacking direction of the cooling water passage and the inner wall surface of the tank. An inlet pipe side guide that guides cooling water flowing along the inner wall surface of the tank on the inlet pipe side to the upstream side of the exhaust passage, and faces the cooling water inlet pipe through the cooling water passage between the exhaust passages. among wall surface for guiding the cooling water flowing so as to face the cooling water flow the guided by the inlet pipe-side guide part to the outermost cooling water passage after colliding with the inner wall surface of the tank to the upstream side of the exhaust passage With a guide,
An exhaust heat exchanger, wherein a gap is formed between the inlet pipe side guide part and the inner wall surface side guide part .

It said guide means, an exhaust heat exchanger according to claim 1, characterized in that it is formed so as to project into the cooling water passage from the outer wall surface of the exhaust passage.

The exhaust heat exchanger according to claim 1 or 2, wherein the guide means is formed to extend in the longitudinal direction of the cross section of the exhaust passage.

And have a cross sectional flat shape exhaust gas of the internal combustion engine passes, a plurality of exhaust tubes stacked such that cross the longitudinal direction to face each other,
A tank containing these exhaust tubes inside;
A cooling water passage formed inside the tank, through which cooling water flows around the exhaust passage;
A bonnet connected to an end of the exhaust tube, distributing exhaust gas to the plurality of exhaust tubes, or collecting exhaust gas that has passed through the plurality of exhaust tubes;
A core plate attached near the end of the exhaust tube and defining the bonnet and the cooling water passage;
Which is connected to the tank in a direction crossing the longitudinal direction of the stacking direction and the exhaust passage in the exhaust passage, toward the cooling water passage between an exhaust passage formed between the respective exhaust tube of the cooling water passage a cooling water inlet pipe for flowing coolant Te,
A cooling water outlet pipe for flowing cooling water out of the cooling water passage;
An exhaust heat exchanger comprising guide means provided in the cooling water passage,
The guide means moves the cooling water from the cooling water inlet pipe to the outermost cooling water passage formed between the exhaust tube disposed on the outermost side in the stacking direction of the cooling water passage and the inner wall surface of the tank. An inlet pipe side guide for guiding the cooling water flowing along the inner wall surface of the tank on the inlet pipe side to the vicinity of the tube root where the upstream end of the exhaust tube is attached to the core plate; and the cooling water between the exhaust passages Cooling water that flows through the passage and collides with the inner wall surface of the tank facing the cooling water inlet pipe to face the cooling water flow guided by the inlet pipe side guide portion to the outermost cooling water passage. An inner wall side guide portion that leads to the vicinity of the tube root portion ,
An exhaust heat exchanger, wherein a gap is formed between the inlet pipe side guide part and the inner wall surface side guide part .

The exhaust heat exchanger according to claim 4, wherein the guide means is formed to protrude from an outer wall surface of the exhaust tube.

The exhaust heat exchanger according to any one of claims 1 to 5, wherein the guide means is formed so as to protrude from an inner wall surface of the tank to the cooling water passage.

The exhaust heat exchanger according to any one of claims 4 to 6, wherein the guide means is formed to extend in the longitudinal direction of the cross section of the exhaust tube.

And have a cross section flattened shape exhaust gas you pass the inner combustion engine, a plurality of exhaust passages which are laminated so that cross-sectional longitudinal direction to face each other,
A tank that houses these exhaust passages,
A cooling water passage formed inside the tank, through which cooling water flows around the exhaust passage;
Which is connected to the tank in a direction crossing the longitudinal direction of the stacking direction and the exhaust passage in the exhaust passage, a cooling water inlet pipe for flowing cooling water to the cooling water passage,
A cooling water outlet pipe for flowing cooling water out of the cooling water passage;
Among the cooling water passages, an inter-exhaust passage cooling water passage formed between the exhaust passages, an outermost exhaust passage formed between the outermost exhaust passage disposed in the stacking direction and the inner wall surface of the tank. Anti- reflective means for partitioning a cooling water passage and preventing a reflected flow from flowing from the cooling water passage between the exhaust passages to the outermost cooling water passage along the inner wall surface of the tank facing the cooling water inlet pipe ; An exhaust heat exchanger characterized by comprising: