JP3567096B2 - Exhaust pipe connection structure for water-cooled engine - Google Patents

Exhaust pipe connection structure for water-cooled engine Download PDF

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Publication number
JP3567096B2
JP3567096B2 JP03582999A JP3582999A JP3567096B2 JP 3567096 B2 JP3567096 B2 JP 3567096B2 JP 03582999 A JP03582999 A JP 03582999A JP 3582999 A JP3582999 A JP 3582999A JP 3567096 B2 JP3567096 B2 JP 3567096B2
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Prior art keywords
exhaust pipe
cooling water
inner peripheral
exhaust
exhaust gas
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JP2000234516A (en
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義信 田中
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Kawasaki Motors Ltd
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Kawasaki Jukogyo KK
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
    • F28D7/10—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged one within the other, e.g. concentrically
    • F28D7/106—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits being arranged one within the other, e.g. concentrically consisting of two coaxial conduits or modules of two coaxial conduits

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Joints Allowing Movement (AREA)
  • Exhaust Silencers (AREA)

Description

【０００１】
【発明の属する技術分野】
本願発明は、水冷式エンジンの排気管接続構造に関し、主に、小型滑走艇あるいは小型船舶等に搭載される水冷式エンジンであって、川、湖あるいは海等の外部の水を冷却水として取り入れて排気管を冷却し、しかも、エンジン振動を遮断するために排気管全体をエンジン側の上流側排気管と、排ガス出口側の下流側排気管とに分離した水冷式エンジンに適した排気管接続構造に関する。
【０００２】
【従来の技術】
この種排気管接続構造の従来技術として、特開平１−２９０９１４号公報に記載された構造があり、冷却構造を有していない例としては、図５に示すように一方の排気管４０にソケット部４１を形成し、他方の排気管４２の差込み部４３にリング溝４４を形成し、該リング溝４４に排ガスシール用のリング４５を嵌着しており、該リング４５を介して差込み部４３をソケット部４１に差し込み、かつ、両排気管４０，４２の端縁間に隙間Ｃを置いて接続している。このようにリング４５を介在させ、かつ、差込み式の接続構造とすることにより、接続部において排ガスをシールできると共に、エンジン振動が排ガス出口側の排気管に伝わるのを阻止している。
【０００３】
上記図５の構造に対し、同先行技術文献には、リングが高温になるのを防ぐ手段を備えた構造が記載されている。該構造は、図６に示すように、分離された排気管５０，５１の先端部外周面にそれぞれリング溝５２，５３を形成し、各リング溝５２，５３にそれぞれ排ガスシール用のリング５４，５５を嵌着し、両リング５４，５５の外周側に、冷却水通路５７を有する摺動筒５８を管長さ方向摺動自在に嵌合している。両排気管５０，５１の端縁間には隙間Ｃを置いている。冷却水通路５７は、シリンダヘッド等から冷却水が導入されるようになっている。この構造によれば、リング５４，５５によって排ガスをシールすると共に、差込み式接続構造を採用することにより、一方の排気管から他方の排気管への振動の伝達を抑制し、かつ、冷却水通路５７を流れる冷却水により両リング５４，５５を冷却している。
【０００４】
【発明が解決しようとする課題】
図５の構造では、リング４５が排ガスに直接晒されることにより、リング４５が加熱され、高温となる。また高温化によりリング４５が膨張し、両排気管４２，４０同士の相対的な摺動性が低下する。
【０００５】
図６の構造では、冷却水通路５７を流れる冷却水により、径方向の外周側からリング５４，５５を冷却することはできる。しかし、内周側からの排ガスの影響は阻止できず、排ガス熱が伝わる。
【０００６】
【発明の目的】
本願発明の目的は、水冷エンジンの排気管接続構造において、分離された排気管間の振動伝達を阻止あるいは抑制すると共に、排ガスシール用のリングが高温になるのを防ぐことである。
【０００７】
【課題を解決するための手段】
上記課題を解決するため本願発明は、周壁に冷却水通路１５，２５を有する排気管全体を、エンジン側の上流側排気管１１と排ガス出口側の下流側排気管１２に分離し、一方の排気管１１には、ソケット部３０を形成すると共に該ソケット部３０の内周面に対して径方向に一定の距離を置いた内周側に内周壁延長部２２ａを形成し、他方の排気管１２には上記ソケット部３０の内周面に差込み可能な差込み部３４を形成し、該差込み部３４を、排ガスシール用のＯリング３７を介してソケット部３０の内周面に差し込み、ソケット部３０の外周側に冷却水連絡通路２４を形成すると共に冷却水シール用の筒状弾性材継手を設け、差込み部３４の内周面と内周壁延長部２２ａの外周面との間に、排ガス熱遮断用の断熱空間Ｓを形成している。
【０００８】
排気管全体を上流側排気管と下流側排気管とに分離し、両排気管を、差込み式接続と弾性材継手を利用して接続しているので、エンジン振動は上記接続部分で縁切れし、下流側排気管への振動伝達は阻止あるいは抑制される。
【０００９】
排気管全体は、周壁に形成された冷却水通路を通る冷却水により冷却され、接続部分のＯリングは、ソケット部外方の冷却水連絡通路を通る冷却水により外方から冷却されると共に、排ガス熱遮断用断熱空間により、排ガス熱が内方側から伝達されるのも防ぐことができ、Ｏリングの高温化を防ぐことができる。
【００１０】
【発明の実施の形態】
図１は本願発明による排気管接続構造を適用した２サイクルエンジンの全体略図であり、シリンダ１に排気口２を備え、クランクケース３に吸気口４を備えており、吸気口４に接続されるリードバルブ、吸気管及び吸気装置等は図示していない。排気口２に接続される排気管全体６は、エンジン側の上流側排気管１１と、該上流側排気管１１から分離した排ガス出口側の下流側排気管１２とから構成されている。上流側排気管１１は長さが短くて直径が概ね一様な円筒状に形成されており、ボルト及びナットによりリジットに排気口２に固定されている。下流側排気管１２は、排気チャンバーとしてテーパー状に拡径しかつ縮径する膨張室を有しており、また、周壁を内周壁１６と外周壁１７の二重壁構造とすることにより、環状の冷却水通路１５を形成している。該冷却水通路１５は下流側排気管１２の前端から後端までいたり、後端は排ガス出口１９として後方に向いて開口している。
【００１１】
図２は両排気管１１，１２の接続部の縦断面拡大図を示しており、上流側排気１１の周壁も内周壁２２と外周壁２３を有する二重壁構造となっており、これにより排ガス通路Ｒの周囲に環状の冷却水通路２５を形成している。冷却水通路２５の前端縁（上流端縁）は、シリンダ１の冷却水出口４に連通しており、後端部（下流端部）は径方向の外方に向く開口部２６となっている。上流側排気管１１の後部の外周面には、後端から順に、冷却水連絡通路用の環状凹部２８と、継手取付面２９が段状に形成されており、環状凹部２８の前端部は前記開口部２６に連通している。環状凹部２８の径方向内方側部分は筒型のソケット部３０となっており、該ソケット部３０の内周面に対して径方向に一定距離を置いた内周側にも、筒状の内周壁延長部２２ａが一体に形成されている。
【００１２】
一方、下流側排気管１２は、前端部に内周壁３１と外周壁３２を有する二重壁構造の接続管２１が一体に溶接（Ｗ）されており、内外周壁３１，３２間で前記冷却水通路１５に連通する冷却水通路３３が形成されている。該冷却水通路３３の後端縁は前記冷却水通路１５に連通し、前端部は径方向の外方に向く開口部２７となっている。接続管２１には前側から順に、円筒状の差込み部３４と、冷却水連絡通路用の環状凹部３５と、継手取付面３６が段状に形成されており、環状凹部３５の後端部は前記開口部２７に連通している。なお、下流側排気管１２の本体部分の肉厚は、上流側排気管１１及び接続管２１よりも薄くなっている。
【００１３】
差込み部３４の外周面には、２つの環状溝３７が前後に間隔を置いて形成されており、各環状溝３７内にそれぞれＯリング３８を嵌着してあり、差込み部３４をソケット部３０の内周面に差し込み、Ｏリング３８を介して一定圧で嵌合してある。差込み部３４の厚みＴ１に対し、ソケット部３０の内周面と延長部２２ａの外周面との径方向の距離Ｔ２は大きくなっており、これにより、差込み接続状態において、差込み部３４の内周面と延長部２２ａの外周面との間に環状空間Ｓを形成しており、該環状空間Ｓが排ガス熱遮断用断熱空間となっている。
【００１４】
前記両継手取付面２９，３６に亘って筒形の弾性材継手１３が嵌合し、バンド１３ａにより締着されており、該弾性材継手１３が前記両環状凹部２８，３５の外周を覆うと共にシールすることにより、継手１３と両環状凹部２８，３５でもって冷却水連絡通路２４を形成している。該冷却水連絡通路２４は前端が開口部２６を介して上流側排気管１１の冷却水通路２５に連通し、後端が開口部２７を介して接続管２１の冷却水通路３３及び下流側排気管１１の冷却水通路１５に連通している。
【００１５】
なお、冷却水通路２５，３３内には、内外周壁２２，２３並びに３１，３２を結合するリブ３９ａ，３９ｂ，３９ｃが、周方向に間隔を置いて複数形成されている。
【００１６】
図３は、図２のＩＩＩ−ＩＩＩ断面図であり、要するに差込み接続部分では、外周側から、弾性材継手１３、冷却水連絡通路２４、ソケット部３０、Ｏリング３８、差込み部３４、排ガス熱遮断用断熱空間Ｓ及び内周壁延長部２２ａが順次配置されていることになる。
【００１７】
【作用】
図２において、エンジン振動は、上流側排気管１１には直接伝達されるが、両排気管１１，１２はＯリング３８を介して差込み式で接続されており、かつ、外周面の継手１３はゴム等の弾性材であるので、差込み接続部分でエンジン振動は縁切りされ、下流側排気管１２への伝達は阻止あるいは抑制される。したがって下流側排気管１１は必要以上に肉厚を増加する必要はなく、重量を軽減でき、また、振動騒音の発生も抑制できる。
【００１８】
シリンダへッド１の冷却水出口４から上流側排気管１１の冷却水通路２５に供給される冷却水は、上流側排気管１１を冷却した後、開口部２６からＯリング外方の冷却水連絡通路２４に入り、ここでＯリング３８を外周側から冷却すると共に弾性材継手１３も冷却し、その後、開口部２７から接続管２１の冷却水通路３３を経て下流側排気管１２の冷却水通路１５に入り、下流側排気管１２を冷却した後、図１の後端排ガス出口１９から外部に排出される。
【００１９】
図２のＯリング３８は上記のように径方向の外方からは連絡通路２４の冷却水により冷却され、内方は排ガス熱遮断用断熱空間Ｓよって排ガス熱が伝わりにくくなっているので、Ｏリング３８の加熱高温化を抑制することができる。
【００２０】
図１乃至図３に示す排気系は、排気系全体の冷却装置を備えると共に、シリンダ等から供給され排気系の冷却に利用した冷却水を外部に放出する構成なので、小型滑走艇のように冷却水を海、川あるいは湖のように外部から取り入れ、かつ、排気系全体が狭い艇内に収納される乗り物に適している。
【００２１】
【発明の実施の形態２】
図４は、排ガス熱遮断用断熱空間Ｓに、熱伝導率の低いＳＵＳ材製の環状断熱材９を配置した構造である。その他の構造は図２の構造と同じであり、同じ部品には同じ符号を付している。
【００２２】
【その他の実施の形態】
（１）図１は排気系全体を模式的に表現しているので、排気管全体は一直線状に描いてあるが、実際に小型滑走艇に搭載する形状としては、収納空間に応じた折れ曲がり形状となることもある。
【００２３】
（２）断熱材の材料はＳＵＳ材には限定されず、熱伝導率の低い各種金属を用いることもできる。
【００２４】
（３）弾性材継手１３としては、ゴムの他に弾性を有する合成樹脂などを利用することもできる。
【００２５】
【発明の効果】
（１）分離された両排気管１１，１２をＯリング３８を介した差込み式で接続し、かつ、外周面を弾性材継手１３で接続しているので、エンジン振動は、接続部分で縁切りされ、下流側排気管への伝達は阻止あるいは抑制される。したがって下流側排気管１２は必要以上に肉厚を増加する必要はなく、重量を軽減でき、また、振動騒音の発生も抑制できる。特に機関室が狭い小型滑走艇では、リジットに排気管同士を接続する場合に比べ、組立性及びメンテナンス性もよい。
【００２６】
（２）差込み接続部分のＯリング１３は、冷却水連絡通路２４を通る冷却水により外周側から冷却されると共に、内方は排ガス熱遮断用断熱空間Ｓによって排ガス熱が伝わりにくくなっているので、Ｏリング３８の加熱高温化を抑制することができる。また、弾性材継手１３の加熱も防ぐことができる。
【図面の簡単な説明】
【図１】本願発明を適用した２サイクルエンジンの全体略図である。
【図２】排気管接続部分の拡大縦断面図である。
【図３】図２のＩＩＩ−ＩＩＩ断面図である。
【図４】別の実施の形態の排気管接続部分の拡大縦断面図である。
【図５】従来例の縦断面図である。
【図６】別の従来例の縦断面図である。
【符号の説明】
１ シリンダ
２ 排気口
６ 排気管全体
９ 排ガス熱遮断用断熱材
１１ 上流側排気管
１２ 下流側排気管
１３ 弾性材継手
１５，２５，３３ 冷却水通路
２１ 接続管（下流側排気管の一部）
２４ 冷却水連絡通路
３０ ソケット部
３４ 差込み部
３７ 環状溝
３８ Ｏリング
Ｓ 排ガス熱遮断用環状空間[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exhaust pipe connection structure for a water-cooled engine, which is mainly a water-cooled engine mounted on a personal watercraft or a small boat, and takes in external water such as a river, a lake or the sea as cooling water. Exhaust pipe connection suitable for water-cooled engines in which the entire exhaust pipe is separated into an upstream exhaust pipe on the engine side and a downstream exhaust pipe on the exhaust gas outlet side to cool the exhaust pipe and to shut off engine vibration Regarding the structure.
[0002]
[Prior art]
As a prior art of this kind of exhaust pipe connection structure, there is a structure described in Japanese Patent Application Laid-Open No. 1-290914. As an example without a cooling structure, as shown in FIG. Part 41 is formed, a ring groove 44 is formed in the insertion part 43 of the other exhaust pipe 42, and a ring 45 for exhaust gas sealing is fitted in the ring groove 44, and the insertion part 43 is inserted through the ring 45. Is inserted into the socket portion 41 and is connected with a gap C between the edges of the exhaust pipes 40 and 42. By thus interposing the ring 45 and having a plug-in connection structure, exhaust gas can be sealed at the connection portion, and engine vibration is prevented from being transmitted to the exhaust pipe on the exhaust gas outlet side.
[0003]
In contrast to the structure of FIG. 5, the prior art document describes a structure provided with means for preventing the ring from becoming hot. In this structure, as shown in FIG. 6, ring grooves 52, 53 are formed on the outer peripheral surfaces of the distal ends of the separated exhaust pipes 50, 51, respectively. A sliding cylinder 58 having a cooling water passage 57 is slidably fitted on the outer peripheral side of both rings 54 and 55 in the pipe length direction. A gap C is provided between the edges of both exhaust pipes 50 and 51. The cooling water passage 57 is configured to introduce cooling water from a cylinder head or the like. According to this structure, the exhaust gas is sealed by the rings 54 and 55 and the transmission of vibration from one exhaust pipe to the other exhaust pipe is suppressed by employing a plug-in connection structure, and the cooling water passage is formed. Both rings 54 and 55 are cooled by the cooling water flowing through 57.
[0004]
[Problems to be solved by the invention]
In the structure shown in FIG. 5, the ring 45 is heated to a high temperature by directly exposing the ring 45 to the exhaust gas. In addition, the ring 45 expands due to the high temperature, and the relative slidability between the exhaust pipes 42 and 40 decreases.
[0005]
In the structure of FIG. 6, the rings 54 and 55 can be cooled from the radially outer peripheral side by the cooling water flowing through the cooling water passage 57. However, the influence of the exhaust gas from the inner peripheral side cannot be prevented, and the exhaust gas heat is transmitted.
[0006]
[Object of the invention]
SUMMARY OF THE INVENTION It is an object of the present invention to prevent or suppress the transmission of vibration between separated exhaust pipes in an exhaust pipe connection structure of a water-cooled engine, and to prevent a high temperature of an exhaust gas sealing ring.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention separates an entire exhaust pipe having cooling water passages 15 and 25 in a peripheral wall into an upstream exhaust pipe 11 on an engine side and a downstream exhaust pipe 12 on an exhaust gas outlet side. The pipe 11 has a socket portion 30 formed therein, and an inner peripheral wall extension 22a formed on an inner peripheral side of the inner peripheral surface of the socket portion 30 at a certain distance in the radial direction with respect to an inner peripheral surface of the socket portion 30. Is formed on the inner peripheral surface of the socket portion 30. The insert portion 34 can be inserted into the inner peripheral surface of the socket portion 30 via an O-ring 37 for exhaust gas sealing. A cooling water communication passage 24 is formed on the outer peripheral side of the cylinder, and a cylindrical elastic material joint for cooling water sealing is provided, so that exhaust gas heat is blocked between the inner peripheral surface of the insertion portion 34 and the outer peripheral surface of the inner peripheral wall extension 22a. Heat insulating space S is formed.
[0008]
The entire exhaust pipe is separated into an upstream exhaust pipe and a downstream exhaust pipe, and the two exhaust pipes are connected using a bayonet connection and an elastic joint. Vibration transmission to the downstream exhaust pipe is prevented or suppressed.
[0009]
The entire exhaust pipe is cooled by cooling water passing through a cooling water passage formed on the peripheral wall, and the O-ring of the connection portion is cooled from the outside by cooling water passing through a cooling water communication passage outside the socket. The heat insulation space for shutting off the exhaust gas heat can also prevent the heat of the exhaust gas from being transmitted from the inside, thereby preventing the O-ring from becoming hot.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is an overall schematic view of a two-stroke engine to which an exhaust pipe connection structure according to the present invention is applied. A cylinder 1 has an exhaust port 2, a crankcase 3 has an intake port 4, and is connected to the intake port 4. The reed valve, intake pipe, intake device and the like are not shown. The entire exhaust pipe 6 connected to the exhaust port 2 includes an upstream exhaust pipe 11 on the engine side and a downstream exhaust pipe 12 on the exhaust gas outlet side separated from the upstream exhaust pipe 11. The upstream side exhaust pipe 11 is formed in a cylindrical shape having a short length and a substantially uniform diameter, and is rigidly fixed to the exhaust port 2 with bolts and nuts. The downstream-side exhaust pipe 12 has an expansion chamber that expands and contracts in a tapered shape as an exhaust chamber, and has a double wall structure of an inner peripheral wall 16 and an outer peripheral wall 17 to form an annular chamber. Cooling water passage 15 is formed. The cooling water passage 15 extends from the front end to the rear end of the downstream side exhaust pipe 12, and the rear end is opened rearward as an exhaust gas outlet 19.
[0011]
FIG. 2 is an enlarged vertical cross-sectional view of a connecting portion between the two exhaust pipes 11 and 12, and the peripheral wall of the upstream exhaust 11 also has a double-wall structure having an inner peripheral wall 22 and an outer peripheral wall 23. An annular cooling water passage 25 is formed around the passage R. The front end (upstream end) of the cooling water passage 25 communicates with the cooling water outlet 4 of the cylinder 1, and the rear end (downstream end) is an opening 26 that faces outward in the radial direction. . On the outer peripheral surface of the rear part of the upstream side exhaust pipe 11, an annular concave portion 28 for a cooling water communication passage and a joint mounting surface 29 are formed in a step shape in order from the rear end. It communicates with the opening 26. A radially inward portion of the annular concave portion 28 is a cylindrical socket portion 30, and a cylindrical socket portion 30 is also provided on the inner peripheral side at a constant distance in the radial direction with respect to the inner peripheral surface of the socket portion 30. The inner peripheral wall extension 22a is formed integrally.
[0012]
On the other hand, the downstream side exhaust pipe 12 is integrally welded (W) to a connection pipe 21 having a double wall structure having an inner peripheral wall 31 and an outer peripheral wall 32 at a front end thereof, and the cooling water is provided between the inner and outer peripheral walls 31 and 32. A cooling water passage 33 communicating with the passage 15 is formed. The rear end of the cooling water passage 33 communicates with the cooling water passage 15, and the front end is an opening 27 facing outward in the radial direction. The connecting pipe 21 has, in order from the front side, a cylindrical insertion portion 34, an annular concave portion 35 for a cooling water communication passage, and a joint mounting surface 36 formed in a step shape. It communicates with the opening 27. The thickness of the main body portion of the downstream side exhaust pipe 12 is smaller than that of the upstream side exhaust pipe 11 and the connection pipe 21.
[0013]
On the outer peripheral surface of the insertion portion 34, two annular grooves 37 are formed at an interval in the front and rear, and O-rings 38 are fitted in the respective annular grooves 37, and the insertion portion 34 is connected to the socket portion 30. And is fitted at a constant pressure via an O-ring 38. The radial distance T2 between the inner peripheral surface of the socket portion 30 and the outer peripheral surface of the extension portion 22a is larger than the thickness T1 of the insertion portion 34, so that the inner circumference of the insertion portion 34 in the plugged connection state. An annular space S is formed between the surface and the outer peripheral surface of the extension 22a, and the annular space S is a heat insulating space for shutting off exhaust gas heat.
[0014]
A tubular elastic material joint 13 is fitted over the two joint mounting surfaces 29 and 36 and fastened by a band 13a. The elastic material joint 13 covers the outer circumferences of the annular recesses 28 and 35, and By sealing, the cooling water communication passage 24 is formed by the joint 13 and the two annular concave portions 28 and 35. The front end of the cooling water communication passage 24 communicates with the cooling water passage 25 of the upstream exhaust pipe 11 through the opening 26, and the rear end thereof has the cooling water passage 33 of the connecting pipe 21 and the downstream exhaust gas through the opening 27. It communicates with the cooling water passage 15 of the pipe 11.
[0015]
In the cooling water passages 25, 33, a plurality of ribs 39a, 39b, 39c connecting the inner and outer peripheral walls 22, 23 and 31, 32 are formed at intervals in the circumferential direction.
[0016]
FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 2. In short, at the plug connection portion, from the outer peripheral side, the elastic material joint 13, the cooling water communication passage 24, the socket portion 30, the O-ring 38, the plug portion 34, the exhaust gas heat This means that the heat insulating space S for blocking and the inner peripheral wall extension 22a are sequentially arranged.
[0017]
[Action]
In FIG. 2, the engine vibration is directly transmitted to the upstream exhaust pipe 11, but the two exhaust pipes 11 and 12 are connected in a plug-in manner via an O-ring 38, and the joint 13 on the outer peripheral surface is Since it is an elastic material such as rubber, engine vibrations are cut off at the insertion connection portion, and transmission to the downstream exhaust pipe 12 is prevented or suppressed. Therefore, it is not necessary to increase the thickness of the downstream side exhaust pipe 11 more than necessary, the weight can be reduced, and the generation of vibration noise can be suppressed.
[0018]
The cooling water supplied from the cooling water outlet 4 of the cylinder head 1 to the cooling water passage 25 of the upstream exhaust pipe 11 cools the upstream exhaust pipe 11, and then the cooling water from the opening 26 to the outside of the O-ring. After entering the communication passage 24, the O-ring 38 is cooled from the outer peripheral side and the elastic material joint 13 is also cooled, and then the cooling water of the downstream side exhaust pipe 12 through the cooling water passage 33 of the connecting pipe 21 from the opening 27. After entering the passage 15 and cooling the downstream exhaust pipe 12, the exhaust gas is discharged to the outside from the rear end exhaust gas outlet 19 in FIG.
[0019]
As described above, the O-ring 38 in FIG. 2 is cooled from the outside in the radial direction by the cooling water in the communication passage 24, and the inside is hardly transmitted with the exhaust gas heat by the heat insulating space S for shutting off the exhaust gas. It is possible to suppress the heating of the ring 38 to a high temperature.
[0020]
The exhaust system shown in FIGS. 1 to 3 is provided with a cooling device for the entire exhaust system and discharges cooling water supplied from a cylinder or the like and used for cooling the exhaust system to the outside. It is suitable for vehicles in which water is taken in from the outside, such as a sea, river or lake, and the entire exhaust system is housed in a narrow boat.
[0021]
Embodiment 2 of the present invention
FIG. 4 shows a structure in which an annular heat insulating material 9 made of a SUS material having a low thermal conductivity is arranged in a heat insulating space S for shutting off exhaust gas heat. Other structures are the same as those in FIG. 2, and the same components are denoted by the same reference numerals.
[0022]
[Other embodiments]
(1) Although FIG. 1 schematically shows the entire exhaust system, the entire exhaust pipe is drawn in a straight line. However, the shape to be actually mounted on a small personal watercraft is a bent shape according to the storage space. Sometimes it becomes.
[0023]
(2) The material of the heat insulating material is not limited to the SUS material, and various metals having low thermal conductivity can be used.
[0024]
(3) The elastic joint 13 may be made of a synthetic resin having elasticity in addition to rubber.
[0025]
【The invention's effect】
(1) Since the separated exhaust pipes 11 and 12 are connected in a plug-in manner via an O-ring 38 and the outer peripheral surface is connected by an elastic joint 13, engine vibration is cut off at the connection portion. Transmission to the downstream exhaust pipe is prevented or suppressed. Therefore, it is not necessary to increase the thickness of the downstream side exhaust pipe 12 more than necessary, the weight can be reduced, and the generation of vibration noise can be suppressed. In particular, in a personal watercraft having a narrow engine room, assemblability and maintainability are better than when exhaust pipes are connected to a rigid body.
[0026]
(2) Since the O-ring 13 at the plug-in connection portion is cooled from the outer peripheral side by the cooling water passing through the cooling water communication passage 24, the heat of the exhaust gas is hardly transmitted to the inside by the heat insulating space S for shutting off the exhaust gas heat. And the O-ring 38 can be suppressed from being heated to a high temperature. In addition, heating of the elastic joint 13 can be prevented.
[Brief description of the drawings]
FIG. 1 is an overall schematic diagram of a two-stroke engine to which the present invention is applied.
FIG. 2 is an enlarged vertical sectional view of an exhaust pipe connection portion.
FIG. 3 is a sectional view taken along the line III-III of FIG. 2;
FIG. 4 is an enlarged vertical sectional view of an exhaust pipe connection portion according to another embodiment.
FIG. 5 is a longitudinal sectional view of a conventional example.
FIG. 6 is a longitudinal sectional view of another conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylinder 2 Exhaust port 6 Exhaust pipe whole 9 Exhaust gas heat insulation material 11 Upstream exhaust pipe 12 Downstream exhaust pipe 13 Elastic material joint 15, 25, 33 Cooling water passage 21 Connection pipe (part of downstream exhaust pipe)
24 cooling water communication passage 30 socket part 34 insertion part 37 annular groove 38 O-ring S annular space for shutting off exhaust gas heat

Claims (1)

周壁に冷却水通路１５，２５を有する排気管全体を、エンジン側の上流側排気管１１と排ガス出口側の下流側排気管１２に分離し、一方の排気管１１には、ソケット部３０を形成すると共に該ソケット部３０の内周面に対して径方向に一定の距離を置いた内周側に内周壁延長部２２ａを形成し、他方の排気管１２には上記ソケット部３０の内周面に差込み可能な差込み部３４を形成し、該差込み部３４を、排ガスシール用のＯリング３７を介してソケット部３０の内周面に差し込み、ソケット部３０の外周側に冷却水連絡通路２４を形成すると共に冷却水シール用の筒状弾性材継手を設け、差込み部３４の内周面と内周壁延長部２２ａの外周面との間に、排ガス熱遮断用の断熱空間Ｓを形成していることを特徴とする水冷式エンジンの排気管接続構造。The entire exhaust pipe having cooling water passages 15 and 25 on the peripheral wall is separated into an upstream exhaust pipe 11 on the engine side and a downstream exhaust pipe 12 on the exhaust gas outlet side , and a socket portion 30 is formed in one exhaust pipe 11. At the same time, an inner peripheral wall extension 22a is formed on the inner peripheral side at a constant distance in the radial direction with respect to the inner peripheral surface of the socket portion 30, and the inner peripheral surface of the socket portion 30 is formed on the other exhaust pipe 12. Is formed on the inner peripheral surface of the socket portion 30 via an O-ring 37 for sealing exhaust gas, and the cooling water communication passage 24 is formed on the outer peripheral side of the socket portion 30. At the same time, a tubular elastic material joint for cooling water sealing is provided, and an adiabatic space S for shutting off exhaust gas heat is formed between the inner peripheral surface of the insertion portion 34 and the outer peripheral surface of the inner peripheral wall extension 22a. Exhaust pipe for a water-cooled engine Connection structure.
JP03582999A 1999-02-15 1999-02-15 Exhaust pipe connection structure for water-cooled engine Expired - Fee Related JP3567096B2 (en)

Priority Applications (1)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107461252A (en) * 2017-08-10 2017-12-12 中国北方发动机研究所(天津) Phase cooling exhaust pipe structure behind a kind of whirlpool for shipboard

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107100711A (en) * 2017-04-14 2017-08-29 重庆长安汽车股份有限公司 A kind of engine exhaust sealing structure and engine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107461252A (en) * 2017-08-10 2017-12-12 中国北方发动机研究所(天津) Phase cooling exhaust pipe structure behind a kind of whirlpool for shipboard

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