JP2004346816A

JP2004346816A - Exhaust manifold structure for engine

Info

Publication number: JP2004346816A
Application number: JP2003144224A
Authority: JP
Inventors: Kohei Amano; 浩平天野; Naoyuki Yamagata; 直之山形; Nobuhide Takeshige; 伸秀武重; Kenji Hiramoto; 健治平本
Original assignee: Mazda Motor Corp
Current assignee: Mazda Motor Corp
Priority date: 2003-05-22
Filing date: 2003-05-22
Publication date: 2004-12-09

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust manifold structure for an engine capable of improving the rigidity of an exhaust manifold while keeping high exhaust gas temperature. <P>SOLUTION: This exhaust manifold structure is composed of a flange member 2 composed of an upstream-side flange part 4 mounted on an exhaust manifold mounting face 10a formed on a side face of a cylinder head 10, a downstream-side flange part 5 connected with the upstream-side flange part 4 approximately orthogonally thereto, for mounting downstream-side exhaust system components, and a plurality of branch pipes 3 respectively mounted on each of cylinders in a state that they are joined with the upstream-side flange part 4 at their upstream ends, and the downstream end or a collection part of their downstream ends is joined with the downstream-side flange part 5. As the upstream-side flange part 4 and the downstream-side flange part 5 are integrally connected with each other, the supporting rigidity of the branch pipes 3 can be improved, and the rigidity of the exhaust manifold 1 as a whole can be improved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、エンジンの排気マニホールド構造に関する。
【０００２】
【従来の技術】
従来、始動直後から排気浄化性能を高めるためには、触媒を早期に活性温度まで上昇させることが必要であり、エンジンから触媒に至る排気系での熱損失を抑えることが望まれている。
しかしながら、鋳造製の排気マニホールドを使用した場合、肉厚が厚く熱容量が大きくなるため、触媒に供給される排気ガス温度が低下する。
【０００３】
そこで、下記特許文献１に示すように、ステレンス等耐熱性が高い材質から構成されるパイプ部材によって排気マニホールドを構成することが知られている。
特許文献１に示される排気マニホールドによれば、鋳造製の排気マニホールドに対して耐熱性が高いことからその肉厚を薄くすことができ、排気マニホールドにおける熱容量を小さくすることができる。
【０００４】
【特許文献１】
特開２０００−２７６４２号公報
【発明が解決しようとする課題】
【０００５】
しかしながら、上述の特許文献１によれば、肉圧が薄くされることによって排気マニホールドの剛性が低下してしまうため、排気マニホールド直下に排気ターボ過給機等の重量物が取付けられる場合、重量物の支持剛性が不足するおそれがある。
尚、排気マニホールドの剛性を高めるため、単に、パイプ部材の肉厚を厚くするのでは熱容量が大きくなってしまう。
【０００６】
本発明は、以上のような課題に勘案してなされたもので、その目的は、排気ガス温度を高く維持しつつ、排気マニホールドの剛性を向上可能なエンジンの排気マニホールド構造を提供することにある。
【０００７】
【課題を解決するための手段】
前記目的を達成するため、本発明にあってはその解決手法として次のようにしてある。すなわち、本発明の第１の構成において、多気筒エンジンの排気マニホールド構造において、シリンダヘッドの側面に形成された排気マニホールド取付面に取付けられる上流側フランジ部と、該上流側フランジ部に対して略直交して接合されるとともに排気系部品が取付けられる下流側フランジ部とからなるフランジ部材と、
各気筒毎に対応してそれぞれ設けられ、上流端が上記上流側フランジ部に接合される一方、下流端又は各下流端を集合させた集合部が上記下流側フランジ部に接合される複数の分岐管とから構成してある。
本発明の第１の構成によれば、上流側フランジ部と下流側フランジ部とが一体的に接合されるため、分岐管の肉厚を厚くすることなく分岐管の支持剛性を向上でき、排気マニホールド全体としての剛性を向上することができる。
【０００８】
本発明の第２の構成において、上記分岐管の外周側には、当該分岐管に対して所定の空間を有して分岐管を覆うカバー部材が設けられるよう構成してある。
耐熱性が高い分岐管によって排気マニホールドを構成する場合、肉厚を薄くすることができるため、熱容量が小さくなり、始動直後の触媒の活性に対しては有効であるものの、放熱性も高くなることから保温性が低下し、触媒活性後における排気ガス温度を高温に維持することが難しくなる。
本発明の第２の構成によれば、分岐管の外周に所定の空間を有して分岐管を覆うカバー部材が設けられるため、所定の空間を断熱空間として機能させることができ、排気ガス温度を高温に維持することができる。
【０００９】
本発明の第３の構成において、上記下流側フランジ部は、上記上流側フランジ部の上端部において上流側フランジ部に対して略直交して接合される一方、当該下流側フランジ部には、上記上流側フランジに近接する側に上記分岐管挿入用の分岐管挿入用開口部が形成されるとともに、上記上流側フランジ部から遠い側に上記分岐管内を通過した排気ガスを上記排気系部品に導出するための排気導出用開口部とが形成されており、
上記分岐管は、上流端が上記上流側フランジ部に接合され、その途中が上記分岐管挿入用開口部に挿入された後上記下流側フランジ部上方側に延び上記下流側フランジ部上方側において下方側に向かって湾曲した後、下流端が上記排気導出用開口部に接合されるよう構成してある。
ここで、排気干渉を可及的に抑制するため、排気マニホールドの各分岐管長を長くする場合がある。
しかしながら、本発明において、単に、各分岐管長を長くすると、下流側フランジ部も長くする必要があるため、フランジ部材が大型化するという問題が生じる。
また、通常、排気系上方は温度が高くなることから、その他のエンジン部品、車両部品が配置されることがなく、スペース上余裕がある。
本発明の第３の構成によれば、下流側フランジに排気管挿入用開口部が形成され、分岐管がその排気管挿入用開口部に挿入された後、上方側に延ばされ、その後再び下方に向かって下流側フランジに接合されるため、分岐管を下流側フランジ部の下方側から上方側に亘って配置させることができ、下流側フランジ部を大型化することなく分岐管長を長くすることができる。
また、分岐管はスペースに余裕のあるエンジン上方側に延設されるため、他の部品との干渉を招くことなく分岐管を配置することができる。
【００１０】
本発明の第４の構成において、上記カバー部材は、上記下流側フランジ部よりも下方側に位置する上記分岐管を覆う第１カバー部材と、上記下流側フランジ部よりも上方側に位置する分岐管を覆う第２カバー部材とから構成してある。
本発明の第４の構成によれば、分岐管が下流側フランジを挟んでその上流側と下流側とに分離されて配置される場合であっても、分岐管は、第１カバーと第２カバーとによって覆われるため、排気ガス温度を高温に維持する。
【００１１】
本発明の第５の構成において、上記下流側フランジ部は、上記上流側フランジ部の下端部において上流側フランジ部に対して略直交して接合されるとともに、当該下流側フランジ部には、上記分岐管を通過した排気ガスを上記排気系部品に導出するための排気導出用開口部とが形成されており
上記分岐管は、上流端が上記上流側フランジ部に接合され、下流端が各分岐管の途中が束ねられた後上記排気導出用開口部に接合されるよう構成してある。
本発明の第５の構成によれば、排気マニホールドは、上流側フランジ部、下流側フランジ部及び分岐管とによって略三角形状に構成されるため、排気マニホールドの剛性を向上することができる。
【００１２】
本発明の第６の構成において、上記下流側フランジ部には、排気ターボ過給機が取付けられるよう構成してある。
本発明の第６の構成によれば、下流側フランジ部に排気ターボ過給機が取付けられる場合であっても、排気マニホールドの剛性が向上され、排気ターボ過給機の支持剛性を維持することができる。
【００１３】
【発明の効果】
本発明によれば、排気ガス温度を高く維持しつつ、排気マニホールドの剛性を向上することができる。
【００１４】
【発明の実施の形態】
以下、本発明の実施の形態を図面に基づいて説明する。
（第１の実施の形態）
図１は排気マニホールド（カバー部材は不図示）の側面図、図２は排気マニホールドにカバー部材を取付けた状態において後方側から見た斜視図、図３は図２を左側面から見た側面図、図４は図２を後方正面から見た正面図、図５は図２を上方側から見た平面図、図６は図２を下方側から見た平面図、図７は分岐管の側面図、図８は分岐管を後方側から見た正面図、図９は図５のＡ−Ａ断面図、図１０は図５のＢ−Ｂ断面図、図１１は第１カバー部材の斜視図である。
尚、本実施形態では、４気筒直列型ガソリンエンジンに適用した例を示す。
【００１５】
図１において、排気マニホールド１は、フランジ部材２と、分岐管３とから構成されている。
フランジ部材２は、シリンダヘッド１０の排気マニホールド取付面１０ａに取付けられる上流側フランジ部４と、その上流側フランジ部４の上端部において上流側フランジ部４に略直交するよう接合されるとともに、排気ターボ過給機１１が取付けられる下流側フランジ部５とから構成されている。
尚、排気ターボ過給機１１は、周知であるため詳細な図示は省略するが、排気通路中に配置される排気タービンと、その排気タービンと回転軸を介して連結され、吸気通路中に配置される吸気ブロアとから構成される。
また、排気ターボ過給機１１の下流側の排気通路には、三元触媒やＮＯ吸蔵触媒（共に不図示）等の排気浄化装置が配設されている。
【００１６】
上流側フランジ部４には、図４にも示すように、シリンダヘッド１０に形成された排気ポート（不図示）からの排気ガスを流入する排気流入用開口部４ａが、各気筒毎に対応してそれぞれ形成されている。
【００１７】
また、下流側フランジ部５は、図２、図５、図６に示すように、上流側フランジ部４の長さ方向に沿って延び、各分岐管３の挿入が可能とされる分岐管挿入用開口部５ａが形成される連接部５ｂと、その連接部５ａの左側（図２、図５、図６中）から所定の幅でエンジン後方側に延び、排気導出用開口部５ｃが形成されるフランジ部５ｄとから構成されている。
【００１８】
分岐管３は、図７、図８に示すように、ステンレス製のパイプ部材が接合されて形成されており、各気筒の排気ポートにそれぞれ接合される第１パイプ材３ａ、３ａ、３ａ、３ａと、その第１パイプ材３ａにそれぞれ接合される第２パイプ材３ｂ、３ｂ、３ｂ、３ｂと、その第２パイプ材３ｂを集合して接合する第３パイプ材３ｃ、３ｃ、３ｃ、３ｃ、３ｃと、その第３パイプ材３ｃから上記排気導出用開口部５ｃに接合され、各分岐管３の集合部として構成される第４パイプ材３ｄ、３ｄ、３ｄとから構成されている。
そのように形成された分岐管３は、上流端が上流側フランジ部４に接合され、上方側に湾曲された後分岐管挿入用開口部５ａを挿入された後、下流側フランジ部５の上方において下方側に向かって湾曲された後、排気導出用開口部５ｃに接合されている。
尚、第１の実施の形態では、各分岐管３を集合した集合部を、排気導出用開口部５ｃに接合する例を示したが、排気導出用開口部５ｃを各気筒に対応させてそれぞれ設け、各分岐管３毎に独立して排気導出用開口部５ｃに接合するようにしてもよい。
【００１９】
また、図２乃至図６に示すように、分岐管３の外周には、分岐管３を覆うカバー部材６が設けられている。
カバー部材６は、下流側フランジ部５よりも下方側の各分岐管３（３ａ）を覆う第１カバー部材６ａと、下流側フランジ部５よりも上方側の各分岐管３（３ｂ、３ｃ、３ｄ）を覆う第２カバー部材６ｂとから構成されている。
これら第１カバー部材６ａ、第２カバー部材６ｂは、図９、図１０に示すように、それぞれ分岐管３の外周に対して所定の空間Ｓを有して接合されている。
尚、第１カバー部材６ａは、図１１に示すように構成され、上流側フランジ部４の及び下流側フランジ部５の下面側に接合されている。
また、第２カバー部材６ｂは、図５中６ｂで示すように平面視略Ｌ字状に構成され、下流側フランジ５の上面側に接合されている。
尚、これら第１カバー部材６ａ、第２カバー部材６ｂは、ともにステンレス製またはスチール製の薄板を板金成形し、または板金成形体を接合して形成されており、分岐管３を含め板厚を厚くする必要はない。
【００２０】
以上のように、第１の実施の形態によれば、上流側フランジ部４と下流側フランジ部５とが連接部５ｂを介して一体的に接続されるため、分岐管３の肉厚を厚くすることなく分岐管３の支持剛性を向上でき、排気マニホールド１全体としての剛性を向上することができる。
また、分岐管３の外周に所定の空間Ｓを有して分岐管３を覆うカバー部材６が設けられるため、所定の空間Ｓを断熱空間として機能させることができ、排気ガス温度を高温に維持することができる。
また、下流側フランジ部５に排気管挿入用開口部５ａが形成され、分岐管３がその排気管挿入用開口部５ａに挿入された後、上方側に延ばされ、その後再び下方に向かって下流側フランジ部５に接合されるため、分岐管３を下流側フランジ部５の下方側から上方側に亘って配置させることができ、下流側フランジ部５を大型化することなく分岐管３の長さを長くすることができる。その際、分岐管３はスペースに余裕のあるエンジン上方側に延設されるため、他の部品との干渉を招くことなく分岐管３を配置することができる。
また、下流側フランジ部５に、排気ターボ過給機１１が取付けられる場合であっても、排気マニホールド１の剛性が向上され、排気ターボ過給機１の支持剛性を維持することができる。
【００２１】
（第２の実施の形態）
次に、図１２、図１３に基づいて第２の実施の形態について、説明する。
図１２は第２の実施の形態に関わる排気マニホールド１の分解図、図１３は排気マニホールドの組立て図である。
図１２において、排気マニホールド１は、フランジ部材２０と、各気筒に対応してそれぞれ設けられる分岐管２１と、各分岐管２１を覆うカバー部材２２とから構成されている。
フランジ部材２０は、第１の実施の形態と同様、シリンダヘッド（図１２では不図示）の排気マニホールド取付面（図１２では不図示）に取付けられるとともに、各気筒の排気ポート（不図示）にそれぞれ対応して接続される排気流入用開口部２０ｂ、２０ｂ、２０ｂ、２０ｂが形成される上流側フランジ部２０ａと、その上流側フランジ部２０ａの下端部と連接部２０ｃを介して接合されるとともに、その連接部２０ｃに対して略直交するよう形成され、かつ排気導出用開口部２０ｄが形成される下流側フランジ部２０ｅとから構成されている。
【００２２】
また、分岐管２１は、各気筒に対応してそれぞれ設けられる４つの分岐管２１ａ、２１ｂ、２１ｃ、２１ｄとから構成されており、各分岐管２１ａ〜２１ｄは、その上流端が上記排気流入用開口部２０ｂにそれぞれ接合されるとともに、下流端が円形に形成された内径から徐々に略扇型に変形され、その扇型とされた４つの分岐管２１ａ、２１ｂ、２１ｃ、２１ｄの下流端が束ねられて円形とされ、排気導出用開口部２０ｄに接合されている。
尚、分岐管２１は、第１の実施の形態と同様、ステンレス製とされている。
また、カバー部材２２は、第１の実施の形態と同様、ステンレス製またはスチール製の薄板を板金成形し、または板金成形体を接合して形成されている。
【００２３】
そして、図１３に示すように、フランジ部材２０に分岐管２１が接合された後、分岐管２１の外周に所定の空間を有して分岐管２１を覆うカバー部材２２がフランジ部材２０に接合されている。
【００２４】
以上のように、第２の実施の形態によれば、第１の実施の形態と同様、上流側フランジ部２０ａと下流側フランジ部２０ｅとが連接部２０ｃを介して一体的に接続されるため、分岐管３の肉厚を厚くすることなく分岐管３の支持剛性を向上でき、排気マニホールド１全体としての剛性を向上することができる。
また、排気マニホールド１は、上流側フランジ部２０ａ、下流側フランジ部２０ｅ及び分岐管２１とによって略三角形状に構成されるため、排気マニホールド１の剛性を向上することができる。
また、分岐管２１の外周に所定の空間を有して分岐管２１を覆うカバー部材２２が設けられるため、排気ガス温度を高温に維持することができる。
【００２５】
尚、本実施の形態では、分岐管３、２１の材質としてステンレス製の例を示したが、スチール製であってもよい。
【００２６】
また、第１の実施の形態では、分岐管３を第１パイプ材３ａ，第２パイプ材３ｂ，第３パイプ材３ｃ，第４パイプ材３ｄの接合により形成したが、第１パイプ材部分と第２パイプ材部分とを一部材で形成する一方、第３パイプ材部分を長寸の一部材で形成し、第４パイプ材部分も一部材で形成して、これら３部材を接合し分岐管とすることもできる。
【００２７】
また、第１の実施の形態では、分岐管３の第１パイプ材３ａを下流側フランジ部５の分岐管挿入用開口部５ａに挿入するようにしたが、各第１パイプ材部分を分岐管と別体にし、上流側フランジ部と下流側フランジ部とに接合し、第１パイプ材部分のない分岐管を下流側フランジ部に接合するようにしてもよい。
【００２８】
また、本実施の形態では、４気筒直列型エンジンに適用する例を示したが、気筒数が４気筒以外のエンジンや、ディーゼルエンジンに適用することも可能である。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態に係る排気マニホールド（カバー部材は不図示）の側面図。
【図２】本発明の第１の実施の形態に係る排気マニホールドにカバー部材を取付けた状態において後方側から見た斜視図。
【図３】本発明の第１の実施の形態に係る図２を左側面から見た側面図。
【図４】本発明の第１の実施の形態に係る図２を後方正面から見た正面図。
【図５】本発明の第１の実施形態に係る図２を上方側から見た平面図。
【図６】本発明の第１の実施形態に係る図２を下方側から見た平面図。
【図７】本発明の第１の実施の形態に係る分岐管の側面図。
【図８】本発明の第１の実施の形態に係る分岐管を後方側から見た正面図。
【図９】本発明の第１の実施の形態に係る図５のＡ−Ａ断面図。
【図１０】本発明の第１の実施の形態に係る図５のＢ−Ｂ断面図。
【図１１】本発明の第１の実施の形態に係る第１カバー部材の斜視図。
【図１２】本発明の第２実施の形態に係る排気マニホールド１の分解図。
【図１３】本発明の第２の実施の形態に係る排気マニホールドの組立て図。
【符号の説明】
１：排気マニホールド
２、２０：フランジ部材
３、２１：分岐管
４、２０ａ：上流側フランジ部
５、２０ｅ：下流側フランジ部
５ａ：分岐管挿入用開口部
５ｂ、２０ｄ：排気導出用開口部
６、２２：カバー部材
６ａ：第１カバー部材
６ｂ：第２カバー部材
１０：シリンダヘッド
１０ａ：排気マニホールド取付面
１１：排気ターボ過給機[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exhaust manifold structure for an engine.
[0002]
[Prior art]
Conventionally, in order to enhance exhaust purification performance immediately after starting, it is necessary to raise the temperature of the catalyst to the activation temperature early, and it is desired to suppress heat loss in the exhaust system from the engine to the catalyst.
However, when a cast exhaust manifold is used, the thickness of the exhaust manifold is large and the heat capacity is large, so that the temperature of the exhaust gas supplied to the catalyst decreases.
[0003]
Therefore, as shown in Patent Literature 1 below, it is known to form an exhaust manifold with a pipe member made of a material having high heat resistance such as stainless steel.
According to the exhaust manifold disclosed in Patent Literature 1, since the heat resistance of the exhaust manifold is high, the thickness of the exhaust manifold can be reduced, and the heat capacity of the exhaust manifold can be reduced.
[0004]
[Patent Document 1]
JP 2000-27642 A [Problems to be solved by the invention]
[0005]
However, according to Patent Document 1 described above, the rigidity of the exhaust manifold is reduced due to the reduction in the wall pressure. Therefore, when a heavy object such as an exhaust turbocharger is mounted immediately below the exhaust manifold, the heavy May have insufficient supporting rigidity.
It should be noted that simply increasing the wall thickness of the pipe member to increase the rigidity of the exhaust manifold increases the heat capacity.
[0006]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an exhaust manifold structure of an engine capable of improving the exhaust manifold rigidity while maintaining a high exhaust gas temperature. .
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides the following as a solution. That is, in the first configuration of the present invention, in the exhaust manifold structure of the multi-cylinder engine, the upstream flange portion attached to the exhaust manifold mounting surface formed on the side surface of the cylinder head, and the upstream flange portion substantially A flange member consisting of a downstream flange portion which is orthogonally joined and to which an exhaust system component is attached,
A plurality of branches are provided corresponding to each cylinder, and an upstream end is joined to the upstream flange portion, while a downstream end or a gathering portion where the downstream ends are gathered is joined to the downstream flange portion. It consists of a pipe and a tube.
According to the first configuration of the present invention, since the upstream flange portion and the downstream flange portion are integrally joined, the support rigidity of the branch pipe can be improved without increasing the thickness of the branch pipe, and the exhaust gas can be exhausted. The rigidity of the entire manifold can be improved.
[0008]
In the second configuration of the present invention, a cover member that covers the branch pipe with a predetermined space with respect to the branch pipe is provided on the outer peripheral side of the branch pipe.
When the exhaust manifold is composed of branch pipes with high heat resistance, the wall thickness can be reduced, so the heat capacity is small, and although it is effective for the activity of the catalyst immediately after starting, the heat dissipation is also high. Therefore, it becomes difficult to maintain the exhaust gas temperature at a high temperature after the catalytic activity.
According to the second configuration of the present invention, since the cover member that covers the branch pipe with the predetermined space is provided on the outer periphery of the branch pipe, the predetermined space can function as a heat insulating space, and the exhaust gas temperature can be reduced. Can be maintained at a high temperature.
[0009]
In the third configuration of the present invention, the downstream flange portion is joined to the upstream flange portion at an upper end portion of the upstream flange portion substantially orthogonally to the upstream flange portion, while the downstream flange portion includes A branch pipe insertion opening for inserting the branch pipe is formed on a side close to the upstream flange, and exhaust gas that has passed through the inside of the branch pipe to a side far from the upstream flange is led to the exhaust system component. And an exhaust outlet opening for performing
The branch pipe has an upstream end joined to the upstream flange portion, and the middle thereof is inserted into the branch pipe insertion opening and then extends upward to the downstream flange portion, and extends downward to the upper portion of the downstream flange portion. After being curved toward the side, the downstream end is configured to be joined to the exhaust outlet opening.
Here, in order to suppress exhaust interference as much as possible, the length of each branch pipe of the exhaust manifold may be increased.
However, in the present invention, if the length of each branch pipe is simply increased, the downstream flange portion also needs to be increased, which causes a problem that the flange member becomes large.
Further, since the temperature in the upper part of the exhaust system is usually high, other engine parts and vehicle parts are not arranged, so that there is room in space.
According to the third configuration of the present invention, the exhaust pipe insertion opening is formed in the downstream flange, and after the branch pipe is inserted into the exhaust pipe insertion opening, the branch pipe is extended upward and then again. Since the branch pipe is joined to the downstream flange downward, the branch pipe can be arranged from the lower side to the upper side of the downstream flange section, and the branch pipe length can be increased without increasing the size of the downstream flange section. be able to.
In addition, since the branch pipe extends above the engine having a sufficient space, the branch pipe can be arranged without causing interference with other components.
[0010]
In a fourth configuration of the present invention, the cover member includes a first cover member that covers the branch pipe located below the downstream flange portion, and a branch member located above the downstream flange portion. And a second cover member for covering the tube.
According to the fourth configuration of the present invention, even when the branch pipe is separated and arranged on the upstream side and the downstream side with the downstream side flange interposed therebetween, the branch pipe is formed by the first cover and the second cover. Exhaust gas temperature is kept high because it is covered by the cover.
[0011]
In the fifth configuration of the present invention, the downstream flange portion is joined at a lower end portion of the upstream flange portion substantially orthogonally to the upstream flange portion, and the downstream flange portion includes An exhaust outlet opening for guiding exhaust gas passing through the branch pipe to the exhaust system component is formed, and the branch pipe has an upstream end joined to the upstream flange portion and a downstream end connected to each branch. After being bundled in the middle of the tube, the tube is joined to the exhaust outlet opening.
According to the fifth configuration of the present invention, since the exhaust manifold is formed in a substantially triangular shape by the upstream flange, the downstream flange, and the branch pipe, the rigidity of the exhaust manifold can be improved.
[0012]
In the sixth configuration of the present invention, an exhaust turbocharger is attached to the downstream flange portion.
According to the sixth configuration of the present invention, even when the exhaust turbocharger is attached to the downstream flange portion, the rigidity of the exhaust manifold is improved, and the support rigidity of the exhaust turbocharger is maintained. Can be.
[0013]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the rigidity of an exhaust manifold can be improved, maintaining exhaust gas temperature high.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First Embodiment)
1 is a side view of an exhaust manifold (a cover member is not shown), FIG. 2 is a perspective view of the exhaust manifold with a cover member attached thereto, as viewed from the rear side, and FIG. 3 is a side view of FIG. 2 as viewed from the left side. 4 is a front view of FIG. 2 as viewed from the rear, FIG. 5 is a plan view of FIG. 2 as viewed from above, FIG. 6 is a plan view of FIG. 2 as viewed from below, and FIG. FIG. 8, FIG. 8 is a front view of the branch pipe viewed from the rear side, FIG. 9 is a sectional view taken along line AA of FIG. 5, FIG. 10 is a sectional view taken along line BB of FIG. 5, and FIG. It is.
In this embodiment, an example in which the present invention is applied to a 4-cylinder in-line gasoline engine will be described.
[0015]
In FIG. 1, the exhaust manifold 1 includes a flange member 2 and a branch pipe 3.
The flange member 2 is joined to the upstream flange portion 4 attached to the exhaust manifold attachment surface 10 a of the cylinder head 10, and is joined to the upper end portion of the upstream flange portion 4 so as to be substantially orthogonal to the upstream flange portion 4. And a downstream flange portion 5 to which the turbocharger 11 is attached.
Although the exhaust turbocharger 11 is well known and is not shown in detail, the exhaust turbocharger 11 is disposed in an exhaust passage, connected to the exhaust turbine via a rotating shaft, and disposed in the intake passage. And an intake blower.
In the exhaust passage downstream of the exhaust turbocharger 11, an exhaust purification device such as a three-way catalyst or a NO storage catalyst (both not shown) is provided.
[0016]
As shown in FIG. 4, an exhaust inflow opening 4 a through which exhaust gas flows from an exhaust port (not shown) formed in the cylinder head 10 is provided in the upstream flange portion 4 for each cylinder. Each is formed.
[0017]
The downstream flange portion 5 extends along the length direction of the upstream flange portion 4 as shown in FIGS. 2, 5, and 6, and a branch pipe insertion into which each branch pipe 3 can be inserted. Connecting portion 5b in which the opening 5a is formed, and extends rearward of the engine by a predetermined width from the left side (in FIGS. 2, 5, and 6) of the connecting portion 5a, and the exhaust outlet opening 5c is formed. 5d.
[0018]
As shown in FIGS. 7 and 8, the branch pipe 3 is formed by joining stainless steel pipe members, and the first pipe members 3a, 3a, 3a, 3a joined to the exhaust ports of the respective cylinders. A second pipe member 3b, 3b, 3b, 3b respectively joined to the first pipe member 3a, and a third pipe member 3c, 3c, 3c, 3c, which assembles and joins the second pipe member 3b. 3c and a fourth pipe member 3d, 3d, 3d joined from the third pipe member 3c to the exhaust outlet opening 5c and configured as an aggregate of the branch pipes 3.
The upstream end of the branch pipe 3 thus formed is joined to the upstream flange section 4, and after being bent upward, the branch pipe insertion opening 5 a is inserted. And is joined to the exhaust outlet 5c.
Note that, in the first embodiment, an example is shown in which the collecting portion in which the branch pipes 3 are assembled is joined to the exhaust outlet opening 5c, but the exhaust outlet opening 5c is made to correspond to each cylinder. Alternatively, each branch pipe 3 may be independently connected to the exhaust outlet opening 5c.
[0019]
As shown in FIGS. 2 to 6, a cover member 6 that covers the branch pipe 3 is provided on the outer periphery of the branch pipe 3.
The cover member 6 includes a first cover member 6 a that covers each branch pipe 3 (3 a) below the downstream flange 5, and a branch pipe 3 (3 b, 3 c) above the downstream flange 5. 3d).
As shown in FIGS. 9 and 10, the first cover member 6a and the second cover member 6b are joined to the outer circumference of the branch pipe 3 with a predetermined space S therebetween.
The first cover member 6a is configured as shown in FIG. 11, and is joined to the lower surface of the upstream flange 4 and the lower surface of the downstream flange 5.
The second cover member 6b is formed in a substantially L-shape in plan view as shown by 6b in FIG. 5, and is joined to the upper surface side of the downstream flange 5.
The first cover member 6a and the second cover member 6b are both formed by sheet metal forming of a thin plate made of stainless steel or steel or by joining sheet metal formed bodies. There is no need to be thick.
[0020]
As described above, according to the first embodiment, since the upstream flange portion 4 and the downstream flange portion 5 are integrally connected via the connecting portion 5b, the thickness of the branch pipe 3 is increased. Therefore, the support rigidity of the branch pipe 3 can be improved, and the rigidity of the exhaust manifold 1 as a whole can be improved.
Further, since the cover member 6 that covers the branch pipe 3 with a predetermined space S is provided on the outer periphery of the branch pipe 3, the predetermined space S can function as a heat insulating space, and the exhaust gas temperature is maintained at a high temperature. can do.
Further, an exhaust pipe insertion opening 5a is formed in the downstream flange 5, and after the branch pipe 3 is inserted into the exhaust pipe insertion opening 5a, it is extended upward and then downward again. Since the branch pipe 3 is joined to the downstream flange 5, the branch pipe 3 can be arranged from the lower side to the upper side of the downstream flange 5, and the branch pipe 3 can be arranged without increasing the size of the downstream flange 5. The length can be lengthened. At this time, since the branch pipe 3 is extended above the engine having a sufficient space, the branch pipe 3 can be arranged without causing interference with other components.
Further, even when the exhaust turbocharger 11 is attached to the downstream flange portion 5, the rigidity of the exhaust manifold 1 is improved, and the support rigidity of the exhaust turbocharger 1 can be maintained.
[0021]
(Second embodiment)
Next, a second embodiment will be described with reference to FIGS.
FIG. 12 is an exploded view of the exhaust manifold 1 according to the second embodiment, and FIG. 13 is an assembly view of the exhaust manifold.
In FIG. 12, the exhaust manifold 1 includes a flange member 20, branch pipes 21 provided for each cylinder, and a cover member 22 that covers each branch pipe 21.
Similar to the first embodiment, the flange member 20 is attached to an exhaust manifold attachment surface (not shown in FIG. 12) of a cylinder head (not shown in FIG. 12), and is attached to an exhaust port (not shown) of each cylinder. The upstream flange portion 20a in which the exhaust inflow openings 20b, 20b, 20b, 20b which are respectively connected are formed, and the lower flange portion of the upstream flange portion 20a is joined to the lower flange portion via the connecting portion 20c. And a downstream flange portion 20e formed substantially perpendicular to the connecting portion 20c and formed with an exhaust outlet opening 20d.
[0022]
The branch pipe 21 is composed of four branch pipes 21a, 21b, 21c, and 21d provided corresponding to the respective cylinders, and each of the branch pipes 21a to 21d has an upstream end for the exhaust inflow. Each of the branch pipes 21a, 21b, 21c, and 21d is joined to the opening 20b, and the downstream end is gradually deformed into a substantially sector shape from the circular inner diameter. It is bundled into a circular shape and joined to the exhaust outlet opening 20d.
Note that the branch pipe 21 is made of stainless steel, as in the first embodiment.
Further, as in the first embodiment, the cover member 22 is formed by sheet metal forming a thin plate made of stainless steel or steel, or by joining a sheet metal formed body.
[0023]
Then, as shown in FIG. 13, after the branch pipe 21 is joined to the flange member 20, a cover member 22 that covers the branch pipe 21 with a predetermined space around the branch pipe 21 is joined to the flange member 20. ing.
[0024]
As described above, according to the second embodiment, similarly to the first embodiment, the upstream flange portion 20a and the downstream flange portion 20e are integrally connected via the connecting portion 20c. The support rigidity of the branch pipe 3 can be improved without increasing the thickness of the branch pipe 3, and the rigidity of the exhaust manifold 1 as a whole can be improved.
Further, since the exhaust manifold 1 is formed in a substantially triangular shape by the upstream flange portion 20a, the downstream flange portion 20e, and the branch pipe 21, the rigidity of the exhaust manifold 1 can be improved.
Further, since the cover member 22 that covers the branch pipe 21 with a predetermined space is provided on the outer periphery of the branch pipe 21, the exhaust gas temperature can be maintained at a high temperature.
[0025]
In the present embodiment, an example has been described in which the branch pipes 3 and 21 are made of stainless steel, but they may be made of steel.
[0026]
In the first embodiment, the branch pipe 3 is formed by joining the first pipe member 3a, the second pipe member 3b, the third pipe member 3c, and the fourth pipe member 3d. The second pipe member is formed of one member, the third pipe member is formed of one long member, and the fourth pipe member is formed of one member. It can also be.
[0027]
Further, in the first embodiment, the first pipe member 3a of the branch pipe 3 is inserted into the branch pipe insertion opening 5a of the downstream flange portion 5. However, each first pipe member portion is connected to the branch pipe. Alternatively, the branch pipe may be joined to the upstream flange section and the downstream flange section, and the branch pipe without the first pipe material portion may be joined to the downstream flange section.
[0028]
In this embodiment, an example in which the present invention is applied to a four-cylinder in-line engine has been described. However, the present invention can be applied to an engine having a number of cylinders other than four or a diesel engine.
[Brief description of the drawings]
FIG. 1 is a side view of an exhaust manifold (a cover member is not shown) according to a first embodiment of the present invention.
FIG. 2 is a perspective view of the exhaust manifold according to the first embodiment of the present invention as viewed from the rear side with a cover member attached.
FIG. 3 is a side view of FIG. 2 according to the first embodiment of the present invention viewed from the left side.
FIG. 4 is a front view of FIG. 2 according to the first embodiment of the present invention as viewed from the rear and front.
FIG. 5 is a plan view of FIG. 2 according to the first embodiment of the present invention as viewed from above.
FIG. 6 is a plan view of FIG. 2 according to the first embodiment of the present invention as viewed from below.
FIG. 7 is a side view of the branch pipe according to the first embodiment of the present invention.
FIG. 8 is a front view of the branch pipe according to the first embodiment of the present invention as viewed from the rear side.
FIG. 9 is a sectional view taken along line AA of FIG. 5 according to the first embodiment of the present invention.
FIG. 10 is a sectional view taken along line BB of FIG. 5 according to the first embodiment of the present invention.
FIG. 11 is a perspective view of a first cover member according to the first embodiment of the present invention.
FIG. 12 is an exploded view of an exhaust manifold 1 according to a second embodiment of the present invention.
FIG. 13 is an assembly view of an exhaust manifold according to a second embodiment of the present invention.
[Explanation of symbols]
1: Exhaust manifold 2, 20: Flange member 3, 21: Branch pipe 4, 20a: Upstream flange section 5, 20e: Downstream flange section 5a: Branch pipe insertion opening 5b, 20d: Exhaust exhaust opening 6 Reference numeral 22: cover member 6a: first cover member 6b: second cover member 10: cylinder head 10a: exhaust manifold mounting surface 11: exhaust turbocharger

Claims

In the exhaust manifold structure of a multi-cylinder engine,
An upstream flange portion attached to an exhaust manifold attachment surface formed on a side surface of the cylinder head, and a downstream flange portion joined substantially orthogonally to the upstream flange portion and to which exhaust system components are attached. A flange member,
A plurality of branches are provided corresponding to each cylinder, and an upstream end is joined to the upstream flange portion, while a downstream end or a gathering portion where the downstream ends are gathered is joined to the downstream flange portion. An exhaust manifold structure for an engine, comprising: a pipe;

The exhaust manifold structure for an engine according to claim 1, wherein a cover member that covers the branch pipe with a predetermined space with respect to the branch pipe is provided on an outer peripheral side of the branch pipe.

The downstream flange portion is joined substantially orthogonally to the upstream flange portion at the upper end portion of the upstream flange portion, while the downstream flange portion has the above-mentioned portion adjacent to the upstream flange. A branch pipe insertion opening for branch pipe insertion is formed, and an exhaust outlet opening for guiding exhaust gas that has passed through the inside of the branch pipe to a side far from the upstream flange portion to the exhaust system component. Is formed,
The branch pipe has an upstream end joined to the upstream flange portion, and the middle thereof is inserted into the branch pipe insertion opening and then extends upward to the downstream flange portion, and extends downward to the upper portion of the downstream flange portion. The exhaust manifold structure for an engine according to claim 1, wherein after being curved toward the side, a downstream end is joined to the exhaust outlet opening.

The cover member includes a first cover member that covers the branch pipe located below the downstream flange portion, and a second cover member that covers a branch pipe located above the downstream flange portion. The exhaust manifold structure for an engine according to claim 3, wherein the exhaust manifold structure is configured.

The downstream flange portion is joined substantially orthogonally to the upstream flange portion at the lower end portion of the upstream flange portion, and the downstream flange portion is provided with the exhaust gas passing through the branch pipe. An exhaust outlet opening for leading to an exhaust system component is formed,
2. The branch pipe according to claim 1, wherein an upstream end is joined to the upstream flange part, and a downstream end is joined to the exhaust lead-out opening after a part of each branch pipe is bundled. 3. Exhaust manifold structure for the described engine.

The exhaust manifold structure for an engine according to any one of claims 1 to 5, wherein an exhaust turbocharger is attached to the downstream flange portion.