JP4826639B2 - Exhaust pipe structure of internal combustion engine - Google Patents

Exhaust pipe structure of internal combustion engine Download PDF

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JP4826639B2
JP4826639B2 JP2009047145A JP2009047145A JP4826639B2 JP 4826639 B2 JP4826639 B2 JP 4826639B2 JP 2009047145 A JP2009047145 A JP 2009047145A JP 2009047145 A JP2009047145 A JP 2009047145A JP 4826639 B2 JP4826639 B2 JP 4826639B2
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exhaust
exhaust pipe
weir
additive
internal combustion
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JP2010203248A (en
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知樹 馬渕
康一 鈴木
宗弘 壷阪
幹二 瀧田
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Toyota Motor Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/08—Other arrangements or adaptations of exhaust conduits
    • F01N13/082—Other arrangements or adaptations of exhaust conduits of tailpipe, e.g. with means for mixing air with exhaust for exhaust cooling, dilution or evacuation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1453—Sprayers or atomisers; Arrangement thereof in the exhaust apparatus

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Exhaust Silencers (AREA)

Description

本発明は、排気管内に添加弁から添加剤を噴射する内燃機関の排気管構造に関する。   The present invention relates to an exhaust pipe structure of an internal combustion engine in which an additive is injected from an addition valve into the exhaust pipe.

ディーゼルエンジン用のＮＯｘ低減触媒として、選択還元型ＮＯｘ触媒（ＳＣＲ触媒）、ＮＯｘ吸蔵還元型触媒、ＮＯｘ直接還元型触媒等の各種触媒が知られている。例えば尿素ＳＣＲ触媒を備えた排気浄化システムでは、ディーゼルエンジンの排気管に尿素水溶液を添加して排気と混合し、ＮＯｘを還元反応により浄化している（例えば特許文献１〜３参照）。   Various catalysts such as a selective reduction type NOx catalyst (SCR catalyst), a NOx occlusion reduction type catalyst, and a NOx direct reduction type catalyst are known as NOx reduction catalysts for diesel engines. For example, in an exhaust purification system equipped with a urea SCR catalyst, a urea aqueous solution is added to an exhaust pipe of a diesel engine and mixed with exhaust gas, and NOx is purified by a reduction reaction (see, for example, Patent Documents 1 to 3).

これら特許文献では添加剤を排気全体に均一に混合されるように排気流や添加剤（あるいは浄化剤）の噴射方向を考慮している。
特許文献１では浄化剤の排気管内導入位置よりも上流側にて排気流方向に対して傾斜させているが排気管内面からは垂直に立ち上がった遮蔽板を配置して排気に渦流を生じさせている。 In these patent documents, the exhaust flow and the injection direction of the additive (or purifier) are considered so that the additive is uniformly mixed in the entire exhaust gas.
In Patent Document 1, the purifier is inclined with respect to the exhaust flow direction upstream from the introduction position of the purifier in the exhaust pipe, but a shielding plate rising vertically from the inner surface of the exhaust pipe is arranged to generate a vortex in the exhaust. Yes.

特許文献２では排気管の曲がり部の外側に添加弁を配置する凹部を形成して、この凹部内から添加剤を対向する内壁へ向けて噴射すると共に、内壁に付着した添加剤は上流側の環状突起により排気中に導入し易くしている。   In Patent Document 2, a recess for arranging the addition valve is formed outside the bent portion of the exhaust pipe, and the additive is injected from the inside of the recess toward the opposing inner wall, and the additive attached to the inner wall is on the upstream side. An annular protrusion makes it easy to introduce into the exhaust.

特許文献３では添加剤の噴射方向を、壁面形状によって排気流の直交方向に流れるように誘導して、排気全体との均一な混合を実行している。   In Patent Document 3, the injection direction of the additive is induced to flow in the direction perpendicular to the exhaust flow by the wall surface shape, and uniform mixing with the entire exhaust gas is executed.

特開２００７−３３２７９７号公報（第７〜８頁、図２〜７）JP 2007-332797 A (pages 7-8, FIGS. 2-7) 特開２００６−７７６９１号公報（第６〜７頁、図３）JP 2006-77691 A (pages 6-7, FIG. 3) 特開２００８−１２８０４８号公報（第６〜８頁、図３〜６）JP 2008-128048 A (pages 6 to 8, FIGS. 3 to 6)

しかし特許文献１のごとくに排気管内壁に垂直に立ち上がった遮蔽板を形成しても、特にエンジンが低回転時などで排気流量が少ない場合には、遮蔽板にて十分に渦流状態とならない排気流が添加弁に到達して、添加弁から噴射される添加剤を排気流全体に十分に混合させることなく下流に流してしまう場合がある。   However, even if a shielding plate that stands vertically on the inner wall of the exhaust pipe is formed as in Patent Document 1, especially when the engine has a low engine speed and the exhaust flow rate is small, the shielding plate does not sufficiently eddy current. The flow may reach the addition valve and cause the additive injected from the addition valve to flow downstream without being fully mixed into the entire exhaust stream.

添加弁から噴射される添加剤を均一に排気中に分散させるために、特許文献２のごとく排気管内面から凹状に窪んで形成された部分（凹状空間）に添加弁を配置する場合がある。しかし、このような配置では排気流量が少ない場合には凹状空間上を排気流がそのまま通過せずに凹状空間内に入り込む。このように入り込んだ排気流が、排気流量の低下に対応して少量噴射される添加剤を直ちに排気管の管壁に付着させてしまう状態となり、噴射される添加剤を排気流全体へ分散することが困難となる。   In order to uniformly disperse the additive injected from the addition valve in the exhaust, the addition valve may be arranged in a portion (concave space) formed in a concave shape from the inner surface of the exhaust pipe as in Patent Document 2. However, in such an arrangement, when the exhaust gas flow rate is small, the exhaust flow does not pass through the concave space as it is and enters the concave space. The exhaust flow that has entered in this manner causes a small amount of additive injected in response to a decrease in the exhaust flow rate to immediately adhere to the pipe wall of the exhaust pipe, and the injected additive is dispersed throughout the exhaust flow. It becomes difficult.

特許文献３においては、一部分の壁面に沿って添加剤を噴射しているので、特に還元剤が少量となる低排気流量時には、排気管の一部の管壁に付着させてしまう状態となり添加剤を排気流全体へ分散することが困難である。   In Patent Document 3, since the additive is injected along a part of the wall surface, the additive is in a state of being attached to a part of the wall of the exhaust pipe, particularly at a low exhaust flow rate with a small amount of reducing agent. Is difficult to disperse to the entire exhaust stream.

このように前記特許文献１〜３においては、排気流量が少ない場合の対策はなされておらず、低排気流量時に添加剤の均一分散が困難となるおそれがある。
本発明は、排気流量の多少に関わらず排気中への添加剤の均一分散を可能とする内燃機関の排気管構造を目的とするものである。 As described above, in Patent Documents 1 to 3, no countermeasure is taken when the exhaust gas flow rate is small, and it is difficult to uniformly disperse the additive at a low exhaust gas flow rate.
An object of the present invention is to provide an exhaust pipe structure for an internal combustion engine that can uniformly disperse the additive in the exhaust gas regardless of the flow rate of the exhaust gas.

以下、上記目的を達成するための手段及びその作用・効果について記載する。
請求項１に記載の内燃機関の排気管構造は、排気管内に添加弁から添加剤を噴射する内燃機関の排気管構造であって、前記添加弁の噴射口配置位置の排気上流側に管壁内面から突出し、排気の流動方向に対向する前面が管壁内面に対して斜めに立ち上げられた堰と、前記堰が設けられた管壁内面とは対向する管壁内面に設けた凹部とを備え、前記堰と共に、前記噴射口配置位置の排気下流側にて管壁内面から突出した堰を設けて、排気上流側と下流側とで前記噴射口配置位置を２つの堰にて挟んでいることを特徴とする。 In the following, means for achieving the above-mentioned purpose, and its operation and effect are described.
The exhaust pipe structure of an internal combustion engine according to claim 1 is an exhaust pipe structure of an internal combustion engine that injects an additive from an addition valve into the exhaust pipe, and a pipe wall on an upstream side of an exhaust port arrangement position of the addition valve. A weir that protrudes from the inner surface and has a front surface facing the exhaust wall flow direction obliquely raised with respect to the inner surface of the tube wall, and a recess provided on the inner surface of the tube wall opposite to the inner surface of the tube wall provided with the weir In addition to the weir, a weir protruding from the inner surface of the pipe wall is provided on the exhaust downstream side of the injection port arrangement position, and the injection port arrangement position is sandwiched between two weirs on the exhaust upstream side and the downstream side It is characterized by that.

このような管壁内面から突出した堰が、添加弁の噴射口配置位置の排気上流側に設けられていることにより、管壁内面に沿って流れてきた排気は、添加弁の噴射口配置位置の直前で堰に到達する。この堰が設けられた管壁内面とは対向する管壁内面に凹部が設けられていることにより、排気流量の多少に関わらず排気は、添加弁の噴射口配置位置が存在する側の管壁内面から跳ね上げられて排気流は噴射口配置位置が存在する側の管壁内面から一旦離れる。このため、堰の下流において噴射口配置位置の周りに排気流が流れ込まない空間が形成される。さらに、堰を排気上流側と共に下流側にも設けることにより、渦流なども含めて、より確実に排気流を噴射口配置位置の周辺に入り込まないようにすることができる。したがって添加弁からの添加剤噴射は、このような排気流が入り込まない空間になされることになる。 By providing such a weir protruding from the inner surface of the tube wall on the exhaust upstream side of the injection valve arrangement position of the addition valve, the exhaust gas flowing along the inner surface of the pipe wall is disposed at the injection port arrangement position of the addition valve. Reach the weir just before. By providing a recess on the inner surface of the tube wall opposite to the inner surface of the tube wall where the weir is provided, the exhaust is exhausted regardless of the flow rate of the exhaust gas. The exhaust flow is bounced up from the inner surface and once leaves the inner surface of the tube wall on the side where the injection port is located. For this reason, the space where the exhaust flow does not flow is formed around the injection port arrangement position downstream of the weir. Furthermore, by providing the weir on the downstream side as well as on the exhaust upstream side, it is possible to prevent the exhaust flow from entering the periphery of the injection port arrangement position more reliably, including vortex flow. Therefore, the additive injection from the addition valve is performed in a space in which such an exhaust flow does not enter.

排気流が入り込まない空間に噴射された添加剤は、いきなり排気流に運ばれることがないので、この空間のほぼ全体に広がった後、この空間と排気流が流れる空間との境界面から排気流内に分散することになる。 Additive is injected into the space where the exhaust flow does not enter, there is no be suddenly transported to the exhaust flow substantially after spread throughout, the exhaust stream from a boundary surface between the space in which the exhaust stream and the space flows in the space Will be dispersed within.

特に内燃機関の排気流量が少ない場合には、噴射される添加剤の量も少ないが、このように添加剤が少ない場合にも、排気流が入り込まない空間内にて十分に添加剤が拡散するので、添加剤が排気管の管壁に直ちに付着するということがない。添加剤の拡散後に空間の境界面から排気流に更に拡散して運ばれることになるので、低排気流量時にも排気中への添加剤の均一分散が行われる。   In particular, when the exhaust gas flow rate of the internal combustion engine is small, the amount of additive injected is small, but even when the additive amount is small, the additive sufficiently diffuses in the space where the exhaust flow does not enter. Therefore, the additive does not immediately adhere to the pipe wall of the exhaust pipe. After the additive is diffused, it is further diffused and carried from the boundary surface of the space to the exhaust flow, so that the additive is uniformly dispersed in the exhaust even at a low exhaust flow rate.

このように排気流量の多少に関わらず排気中への添加剤の均一分散を可能とすることができる。 In this way, the additive can be uniformly dispersed in the exhaust regardless of the exhaust flow rate .

また、同構成のように堰の前面が管壁内面に対して斜めに立ち上がっていることにより、渦流発生を抑制して円滑に排気の流れを誘導できる。このため堰の下流において噴射口配置位置の周りに排気流が流れ込まない空間を十分に形成でき、前述したごとく排気流量の多少に関わらず排気中への添加剤の均一分散を可能とすることができる。 Further, since the front surface of the weir rises obliquely with respect to the inner surface of the tube wall as in the same configuration , the flow of exhaust can be smoothly induced while suppressing the generation of vortex. For this reason, it is possible to sufficiently form a space where the exhaust flow does not flow around the injection port arrangement position downstream of the weir, and as described above, it is possible to uniformly disperse the additive in the exhaust regardless of the exhaust flow rate. it can.

請求項２に記載の内燃機関の排気管構造では、排気管内に添加弁から添加剤を噴射する内燃機関の排気管構造であって、前記添加弁の噴射口配置位置の排気上流側に管壁内面から突出し、排気の流動方向に対向する前面が管壁内面に対して斜めに立ち上げられた堰と、前記堰が設けられた管壁内面とは対向する管壁内面に設けた凹部とを備え、前記噴射口配置位置は、排気管の曲がり部分における内側、又は排気管の曲がり部分の近傍における内側に配置されていることを特徴とする。 3. The exhaust pipe structure of an internal combustion engine according to claim 2 , wherein the exhaust pipe structure of the internal combustion engine injects the additive from the addition valve into the exhaust pipe, and the pipe wall is disposed upstream of the exhaust valve arrangement position of the addition valve. A weir that protrudes from the inner surface and has a front surface facing the exhaust wall flow direction obliquely raised with respect to the inner surface of the tube wall, and a recess provided on the inner surface of the tube wall opposite to the inner surface of the tube wall provided with the weir The injection port is arranged at the inside of the bent portion of the exhaust pipe or inside the bent portion of the exhaust pipe .

このような管壁内面から突出した堰が、添加弁の噴射口配置位置の排気上流側に設けられていることにより、管壁内面に沿って流れてきた排気は、添加弁の噴射口配置位置の直前で堰に到達する。この堰が設けられた管壁内面とは対向する管壁内面に凹部が設けられていることにより、排気流量の多少に関わらず排気は、添加弁の噴射口配置位置が存在する側の管壁内面から跳ね上げられて排気流は噴射口配置位置が存在する側の管壁内面から一旦離れる。このため、堰の下流において噴射口配置位置の周りに排気流が流れ込まない空間が形成される。したがって添加弁からの添加剤噴射は、このような排気流が入り込まない空間になされることになる。  By providing such a weir protruding from the inner surface of the tube wall on the exhaust upstream side of the injection valve arrangement position of the addition valve, the exhaust gas flowing along the inner surface of the pipe wall is disposed at the injection port arrangement position of the addition valve. Reach the weir just before. By providing a recess on the inner surface of the tube wall opposite to the inner surface of the tube wall where the weir is provided, the exhaust is exhausted regardless of the flow rate of the exhaust gas. The exhaust flow is bounced up from the inner surface and once leaves the inner surface of the tube wall on the side where the injection port is located. For this reason, the space where the exhaust flow does not flow is formed around the injection port arrangement position downstream of the weir. Therefore, the additive injection from the addition valve is performed in a space in which such an exhaust flow does not enter.
排気流が入り込まない空間に噴射された添加剤は、いきなり排気流に運ばれることがないので、この空間のほぼ全体に広がった後、この空間と排気流が流れる空間との境界面から排気流内に分散することになる。  Since the additive injected into the space where the exhaust flow does not enter is suddenly transported to the exhaust flow, it spreads over almost the entire space, and then flows from the boundary surface between this space and the space where the exhaust flow flows. Will be dispersed within.
特に内燃機関の排気流量が少ない場合には、噴射される添加剤の量も少ないが、このように添加剤が少ない場合にも、排気流が入り込まない空間内にて十分に添加剤が拡散するので、添加剤が排気管の管壁に直ちに付着するということがない。添加剤の拡散後に空間の境界面から排気流に更に拡散して運ばれることになるので、低排気流量時にも排気中への添加剤の均一分散が行われる。  In particular, when the exhaust gas flow rate of the internal combustion engine is small, the amount of additive injected is small, but even when the additive amount is small, the additive sufficiently diffuses in the space where the exhaust flow does not enter. Therefore, the additive does not immediately adhere to the pipe wall of the exhaust pipe. After the additive is diffused, it is further diffused and carried from the boundary surface of the space to the exhaust flow, so that the additive is uniformly dispersed in the exhaust even at a low exhaust flow rate.
また、排気管の曲がり部分の内側、又はこの近傍位置の内側に噴射口配置位置を設定した場合には、排気管設計上などの制約から、噴射口配置位置へ排気流が入り込み易くなるような配置や形状となる場合がある。しかし、このような場合にも前述したごとくの堰及び凹部を設けることで、容易に噴射口配置位置へ排気流が入り込みにくくできる。  Further, when the injection port arrangement position is set inside the bent portion of the exhaust pipe or inside the vicinity thereof, the exhaust flow easily enters the injection port arrangement position due to restrictions on the exhaust pipe design. It may be arranged or shaped. However, even in such a case, by providing the weir and the recess as described above, the exhaust flow can be easily prevented from entering the injection port arrangement position.
したがって上述した制約が存在しても排気流量の多少に関わらず排気中への添加剤の均一分散を可能とすることができる。  Therefore, even if the above-described restrictions exist, it is possible to uniformly disperse the additive in the exhaust regardless of the amount of exhaust flow.
また、同構成のように堰の前面が管壁内面に対して斜めに立ち上がっていることにより、渦流発生を抑制して円滑に排気の流れを誘導できる。このため堰の下流において噴射口配置位置の周りに排気流が流れ込まない空間を十分に形成でき、前述したごとく排気流量の多少に関わらず排気中への添加剤の均一分散を可能とすることができる。  Further, since the front surface of the weir rises obliquely with respect to the inner surface of the tube wall as in the same configuration, the flow of exhaust can be smoothly induced while suppressing the generation of vortex. For this reason, it is possible to sufficiently form a space where the exhaust flow does not flow around the injection port arrangement position downstream of the weir, and as described above, it is possible to uniformly disperse the additive in the exhaust regardless of the exhaust flow rate. it can.

請求項３に記載の内燃機関の排気管構造では、排気管内に添加弁から添加剤を噴射する内燃機関の排気管構造であって、前記添加弁の噴射口配置位置の排気上流側に管壁内面から突出し、排気の流動方向に対向する前面が管壁内面に対して斜めに立ち上げられた堰と、前記堰が設けられた管壁内面とは対向する管壁内面に設けた凹部とを備え、前記噴射口配置位置は、管壁内面に形成した凹状空間内に配置されていると共に、前記堰は、前記凹状空間の排気上流側の縁部に形成され、当該堰と共に、前記凹状空間の排気下流側の縁部に堰を設けて、排気上流側と下流側とで前記凹状空間を２つの堰にて挟んでいることを特徴とする。 The exhaust pipe structure of an internal combustion engine according to claim 3 , wherein the exhaust pipe structure of the internal combustion engine injects the additive from the addition valve into the exhaust pipe, and the pipe wall is located upstream of the exhaust port arrangement position of the addition valve. A weir that protrudes from the inner surface and has a front surface facing the exhaust wall flow direction obliquely raised with respect to the inner surface of the tube wall, and a recess provided on the inner surface of the tube wall opposite to the inner surface of the tube wall provided with the weir The injection port is disposed in a concave space formed on the inner surface of the tube wall, and the weir is formed at an edge on the exhaust upstream side of the concave space, and together with the weir, the concave space A dam is provided at the edge of the exhaust downstream side, and the concave space is sandwiched between two dams on the exhaust upstream side and the downstream side .

このような管壁内面から突出した堰が、添加弁の噴射口配置位置の排気上流側に設けられていることにより、管壁内面に沿って流れてきた排気は、添加弁の噴射口配置位置の直前で堰に到達する。この堰が設けられた管壁内面とは対向する管壁内面に凹部が設けられていることにより、排気流量の多少に関わらず排気は、添加弁の噴射口配置位置が存在する側の管壁内面から跳ね上げられて排気流は噴射口配置位置が存在する側の管壁内面から一旦離れる。このため、堰の下流において噴射口配置位置の周りに排気流が流れ込まない空間が形成される。さらに、堰を排気上流側と共に下流側にも設けることにより、渦流なども含めて、より確実に排気流を噴射口配置位置の周辺に入り込まないようにすることができる。したがって添加弁からの添加剤噴射は、このような排気流が入り込まない空間になされることになる。  By providing such a weir protruding from the inner surface of the tube wall on the exhaust upstream side of the injection valve arrangement position of the addition valve, the exhaust gas flowing along the inner surface of the pipe wall is disposed at the injection port arrangement position of the addition valve. Reach the weir just before. By providing a recess on the inner surface of the tube wall opposite to the inner surface of the tube wall where the weir is provided, the exhaust is exhausted regardless of the flow rate of the exhaust gas. The exhaust flow is bounced up from the inner surface and once leaves the inner surface of the tube wall on the side where the injection port is located. For this reason, the space where the exhaust flow does not flow is formed around the injection port arrangement position downstream of the weir. Furthermore, by providing the weir on the downstream side as well as on the exhaust upstream side, it is possible to prevent the exhaust flow from entering the periphery of the injection port arrangement position more reliably, including vortex flow. Therefore, the additive injection from the addition valve is performed in a space in which such an exhaust flow does not enter.
排気流が入り込まない空間に噴射された添加剤は、いきなり排気流に運ばれることがないので、この空間のほぼ全体に広がった後、この空間と排気流が流れる空間との境界面から排気流内に分散することになる。  Since the additive injected into the space where the exhaust flow does not enter is suddenly transported to the exhaust flow, it spreads over almost the entire space, and then flows from the boundary surface between this space and the space where the exhaust flow flows. Will be dispersed within.
特に内燃機関の排気流量が少ない場合には、噴射される添加剤の量も少ないが、このように添加剤が少ない場合にも、排気流が入り込まない空間内にて十分に添加剤が拡散するので、添加剤が排気管の管壁に直ちに付着するということがない。添加剤の拡散後に空間の境界面から排気流に更に拡散して運ばれることになるので、低排気流量時にも排気中への添加剤の均一分散が行われる。  In particular, when the exhaust gas flow rate of the internal combustion engine is small, the amount of additive injected is small, but even when the additive amount is small, the additive sufficiently diffuses in the space where the exhaust flow does not enter. Therefore, the additive does not immediately adhere to the pipe wall of the exhaust pipe. After the additive is diffused, it is further diffused and carried from the boundary surface of the space to the exhaust flow, so that the additive is uniformly dispersed in the exhaust even at a low exhaust flow rate.
このように排気流量の多少に関わらず排気中への添加剤の均一分散を可能とすることができる。  In this way, the additive can be uniformly dispersed in the exhaust regardless of the exhaust flow rate.
また、同構成のように堰の前面が管壁内面に対して斜めに立ち上がっていることにより、渦流発生を抑制して円滑に排気の流れを誘導できる。このため堰の下流において噴射口配置位置の周りに排気流が流れ込まない空間を十分に形成でき、前述したごとく排気流量の多少に関わらず排気中への添加剤の均一分散を可能とすることができる。  Further, since the front surface of the weir rises obliquely with respect to the inner surface of the tube wall as in the same configuration, the flow of exhaust can be smoothly induced while suppressing the generation of vortex. For this reason, it is possible to sufficiently form a space where the exhaust flow does not flow around the injection port arrangement position downstream of the weir, and as described above, it is possible to uniformly disperse the additive in the exhaust regardless of the exhaust flow rate. it can.
さらに、排気上流側の縁部に堰を形成した凹状空間内に噴射口配置位置を設定することにより噴射口配置位置の周辺に排気流が入り込まない空間を十分に確保することができ、排気流量の多少に関わらず排気中への添加剤の均一分散効果をより高めることができる。  Furthermore, by setting the injection port arrangement position in the concave space in which the weir is formed at the edge on the upstream side of the exhaust, it is possible to sufficiently secure a space where the exhaust flow does not enter around the injection port arrangement position. Regardless of the amount, the effect of uniformly dispersing the additive in the exhaust gas can be further enhanced.

請求項４に記載の内燃機関の排気管構造では、排気管内に添加弁から添加剤を噴射する内燃機関の排気管構造であって、前記添加弁の噴射口配置位置の排気上流側に管壁内面から突出し、排気の流動方向に対向する前面が管壁内面に対して斜めに立ち上げられた堰と、前記堰が設けられた管壁内面とは対向する管壁内面に設けた凹部とを備え、前記噴射口配置位置は、管壁内面に形成した凹状空間内に配置されていると共に、前記堰は、前記凹状空間の排気上流側の縁部に形成され、前記凹状空間は、排気管の曲がり部分における内側、又は排気管の曲がり部分の近傍における内側に形成されていることを特徴とする。 5. The exhaust pipe structure of an internal combustion engine according to claim 4 , wherein the exhaust pipe structure of the internal combustion engine injects the additive from the addition valve into the exhaust pipe, and the pipe wall on the exhaust upstream side of the injection port arrangement position of the addition valve. A weir that protrudes from the inner surface and has a front surface facing the exhaust wall flow direction obliquely raised with respect to the inner surface of the tube wall, and a recess provided on the inner surface of the tube wall opposite to the inner surface of the tube wall provided with the weir The injection port is disposed in a concave space formed on the inner surface of the tube wall, and the weir is formed on an edge of the concave space on the exhaust upstream side, and the concave space is formed in the exhaust pipe. It is characterized in that it is formed inside the bent portion of the exhaust pipe or inside the bent portion in the vicinity of the exhaust pipe .

このような管壁内面から突出した堰が、添加弁の噴射口配置位置の排気上流側に設けられていることにより、管壁内面に沿って流れてきた排気は、添加弁の噴射口配置位置の直前で堰に到達する。この堰が設けられた管壁内面とは対向する管壁内面に凹部が設けられていることにより、排気流量の多少に関わらず排気は、添加弁の噴射口配置位置が存在する側の管壁内面から跳ね上げられて排気流は噴射口配置位置が存在する側の管壁内面から一旦離れる。このため、堰の下流において噴射口配置位置の周りに排気流が流れ込まない空間が形成される。したがって添加弁からの添加剤噴射は、このような排気流が入り込まない空間になされることになる。  By providing such a weir protruding from the inner surface of the tube wall on the exhaust upstream side of the injection valve arrangement position of the addition valve, the exhaust gas flowing along the inner surface of the pipe wall is disposed at the injection port arrangement position of the addition valve. Reach the weir just before. By providing a recess on the inner surface of the tube wall opposite to the inner surface of the tube wall where the weir is provided, the exhaust is exhausted regardless of the flow rate of the exhaust gas. The exhaust flow is bounced up from the inner surface and once leaves the inner surface of the tube wall on the side where the injection port is located. For this reason, the space where the exhaust flow does not flow is formed around the injection port arrangement position downstream of the weir. Therefore, the additive injection from the addition valve is performed in a space in which such an exhaust flow does not enter.
排気流が入り込まない空間に噴射された添加剤は、いきなり排気流に運ばれることがないので、この空間のほぼ全体に広がった後、この空間と排気流が流れる空間との境界面から排気流内に分散することになる。  Since the additive injected into the space where the exhaust flow does not enter is suddenly transported to the exhaust flow, it spreads over almost the entire space, and then flows from the boundary surface between this space and the space where the exhaust flow flows. Will be dispersed within.
特に内燃機関の排気流量が少ない場合には、噴射される添加剤の量も少ないが、このように添加剤が少ない場合にも、排気流が入り込まない空間内にて十分に添加剤が拡散するので、添加剤が排気管の管壁に直ちに付着するということがない。添加剤の拡散後に空間の境界面から排気流に更に拡散して運ばれることになるので、低排気流量時にも排気中への添加剤の均一分散が行われる。  In particular, when the exhaust gas flow rate of the internal combustion engine is small, the amount of additive injected is small, but even when the additive amount is small, the additive sufficiently diffuses in the space where the exhaust flow does not enter. Therefore, the additive does not immediately adhere to the pipe wall of the exhaust pipe. After the additive is diffused, it is further diffused and carried from the boundary surface of the space to the exhaust flow, so that the additive is uniformly dispersed in the exhaust even at a low exhaust flow rate.
また、排気管の曲がり部分の内側、又はこの近傍位置の内側に凹状空間を形成した場合には、排気管の設計上や凹状空間の成形上などの制約から、凹状空間が排気流の入り込み易くなるような配置や形状となる場合がある。しかし、このような場合にも前述したごとくの堰及び凹部を設けることで容易に凹状空間内へ排気流が入り込みにくくできる。  In addition, when a concave space is formed inside the bent portion of the exhaust pipe or inside the vicinity thereof, the concave space can easily enter the exhaust flow due to restrictions on the design of the exhaust pipe and the formation of the concave space. There are cases where the arrangement and shape are as follows. However, even in such a case, by providing the weir and the concave portion as described above, the exhaust flow can be easily prevented from entering the concave space.
したがって上述した制約が存在しても排気流量の多少に関わらず排気中への添加剤の均一分散を可能とすることができる。  Therefore, even if the above-described restrictions exist, it is possible to uniformly disperse the additive in the exhaust regardless of the amount of exhaust flow.
また、同構成のように堰の前面が管壁内面に対して斜めに立ち上がっていることにより、渦流発生を抑制して円滑に排気の流れを誘導できる。このため堰の下流において噴射口配置位置の周りに排気流が流れ込まない空間を十分に形成でき、前述したごとく排気流量の多少に関わらず排気中への添加剤の均一分散を可能とすることができる。  Further, since the front surface of the weir rises obliquely with respect to the inner surface of the tube wall as in the same configuration, the flow of exhaust can be smoothly induced while suppressing the generation of vortex. For this reason, it is possible to sufficiently form a space where the exhaust flow does not flow around the injection port arrangement position downstream of the weir, and as described above, it is possible to uniformly disperse the additive in the exhaust regardless of the exhaust flow rate. it can.
さらに、排気上流側の縁部に堰を形成した凹状空間内に噴射口配置位置を設定することにより噴射口配置位置の周辺に排気流が入り込まない空間を十分に確保することができ、排気流量の多少に関わらず排気中への添加剤の均一分散効果をより高めることができる。  Furthermore, by setting the injection port arrangement position in the concave space in which the weir is formed at the edge on the upstream side of the exhaust, it is possible to sufficiently secure a space where the exhaust flow does not enter around the injection port arrangement position. Regardless of the amount, the effect of uniformly dispersing the additive in the exhaust gas can be further enhanced.

請求項５に記載の内燃機関の排気管構造では、請求項３又は４に記載の内燃機関の排気管構造において、前記凹状空間は、管壁自身が排気管外側へ膨らんだ形状として形成されていることを特徴とすることを特徴とする。 In the exhaust pipe structure of the internal combustion engine according to claim 5 , in the exhaust pipe structure of the internal combustion engine according to claim 3 or 4, the concave space is formed as a shape in which the tube wall itself swells to the outside of the exhaust pipe. It is characterized by being.

このように凹状空間は管壁自身が排気管外側へ膨らんだ形状として形成され、管壁以外の特別な部材を配置しなくても形成できる。したがって排気管構造の簡素化が可能となり、かつ軽量化にも貢献できる。 Thus, the concave space is formed as a shape in which the tube wall itself swells to the outside of the exhaust pipe, and can be formed without arranging a special member other than the tube wall. Therefore, the exhaust pipe structure can be simplified and can contribute to weight reduction.

請求項６に記載の内燃機関の排気管構造では、請求項１〜５のいずれか一項に記載の内燃機関の排気管構造において、前記堰は、管壁自身が排気管内側へ窪んだ形状として形成されていることを特徴とする。 The exhaust pipe structure for an internal combustion engine according to claim 6, in the exhaust pipe structure of an internal combustion engine according to any one of claims 1 to 5, wherein the weir, recessed tube wall itself to the exhaust pipe inner contour It is formed as follows.

このように管壁内面に遮蔽板のような特別な部材を配置するのではなく、管壁自身の変形により堰を形成すれば、管壁以外の特別な部材を配置しなくても堰が形成できる。したがって排気管構造の簡素化が可能となり、かつ軽量化にも貢献できる。
請求項７に記載の内燃機関の排気管構造では、請求項１〜６のいずれか一項に記載の内燃機関の排気管構造において、前記凹部は、管壁自身が排気管外側へ膨らんだ形状として形成されていることを特徴とする。 In this way, if a dam is formed by deformation of the tube wall itself, instead of arranging a special member such as a shielding plate on the inner surface of the tube wall, the dam is formed without arranging a special member other than the tube wall. it can. Therefore, the exhaust pipe structure can be simplified and can contribute to weight reduction.
The exhaust pipe structure for an internal combustion engine according to claim 7 , wherein in the exhaust pipe structure for the internal combustion engine according to any one of claims 1 to 6 , the concave portion has a shape in which a pipe wall itself swells to the outside of the exhaust pipe. It is formed as follows.

このように凹部は管壁自身が排気管外側へ膨らんだ形状として形成され、管壁以外の特別な部材を配置しなくても形成できる。したがって排気管構造の簡素化が可能となり、かつ軽量化にも貢献できる。Thus, the recess is formed in a shape in which the tube wall itself swells to the outside of the exhaust pipe, and can be formed without arranging any special member other than the tube wall. Therefore, the exhaust pipe structure can be simplified and can contribute to weight reduction.

請求項８に記載の内燃機関の排気管構造では、請求項１〜７のいずれか一項に記載の内燃機関の排気管構造において、前記添加剤は排気浄化用添加剤であることを特徴とする。 The exhaust pipe structure for an internal combustion engine according to claim 8 , wherein the additive is an additive for exhaust purification, in the exhaust pipe structure for an internal combustion engine according to any one of claims 1 to 7. To do.

上述したごとくの構成及び作用により、排気流量の多少に関わらず排気中への排気浄化用添加剤の均一分散を可能とすることができる。
請求項９に記載の内燃機関の排気管構造では、請求項８に記載の内燃機関の排気管構造において、前記添加剤は水溶液の形態であることを特徴とする。 With the configuration and operation as described above, it is possible to uniformly disperse the exhaust purification additive into the exhaust regardless of the exhaust flow rate.
The exhaust pipe structure for an internal combustion engine according to claim 9 is the exhaust pipe structure for an internal combustion engine according to claim 8 , wherein the additive is in the form of an aqueous solution.

このような水溶液の形態での添加剤では水分蒸発前に排気管壁に付着し易くなり排気中への分散に時間を要するが、前述したごとく添加弁からの噴射後に排気流に運ばれるまで拡散や水分を蒸発する時間的余裕が存在するので、水溶液の形態でも排気流量の多少に関わらず排気中への排気浄化用添加剤の均一分散を可能とすることができる。   Such an additive in the form of an aqueous solution tends to adhere to the exhaust pipe wall before evaporation of water and takes time to disperse in the exhaust, but as described above, it diffuses until it is carried to the exhaust stream after injection from the addition valve. Furthermore, since there is a time margin for evaporating water, even in the form of an aqueous solution, it is possible to uniformly disperse the exhaust purification additive into the exhaust regardless of the exhaust flow rate.

請求項１０に記載の内燃機関の排気管構造では、請求項９に記載の内燃機関の排気管構造において、前記添加剤は尿素水溶液であることを特徴とする。
水溶液形態の添加剤としては、尿素水溶液を挙げることができ、この尿素水溶液を用いても、排気流量の多少に関わらず排気中への尿素の均一分散を可能とすることができる。 The exhaust pipe structure for an internal combustion engine according to claim 10 is the exhaust pipe structure for an internal combustion engine according to claim 9 , wherein the additive is an aqueous urea solution.
As an additive in the form of an aqueous solution, an aqueous urea solution can be mentioned, and even when this aqueous urea solution is used, it is possible to uniformly disperse urea in the exhaust gas regardless of the exhaust flow rate.

請求項１１に記載の内燃機関の排気管構造では、請求項１〜１０のいずれか一項に記載の内燃機関の排気管構造において、前記内燃機関はディーゼルエンジンであることを特徴とする。 The exhaust pipe structure for an internal combustion engine according to claim 11 is the exhaust pipe structure for an internal combustion engine according to any one of claims 1 to 10 , wherein the internal combustion engine is a diesel engine.

内燃機関としてはディーゼルエンジンを挙げることができ、ディーゼルエンジンが発生するＮＯｘなどを排気流量の多少に関わらず十分に浄化できる。   An example of the internal combustion engine is a diesel engine, and NOx generated by the diesel engine can be sufficiently purified regardless of the amount of exhaust gas flow.

実施の形態１の排気管の平面図。FIG. 3 is a plan view of the exhaust pipe of the first embodiment. 図１におけるＡ−Ａ線断面図。FIG. 2 is a sectional view taken along line AA in FIG. 1. 実施の形態１の排気管の要部斜視図。FIG. 3 is a perspective view of a main part of the exhaust pipe according to the first embodiment. 実施の形態１の作用・効果を説明する縦断面図。FIG. 3 is a longitudinal sectional view for explaining the operation and effect of the first embodiment. 実施の形態２の排気管の要部斜視図。FIG. 6 is a perspective view of main parts of an exhaust pipe according to a second embodiment. 実施の形態３の排気管の要部斜視図。FIG. 6 is a perspective view of a main part of an exhaust pipe according to a third embodiment. 実施の形態４とその変形例の排気管の縦断面図。The longitudinal cross-sectional view of the exhaust pipe of Embodiment 4 and its modification.

［実施の形態１］
図１〜３はディーゼルエンジンの排気管２における添加剤噴射領域４を示している。図１は平面図、図２はそのＡ−Ａ線断面図、図３は要部斜視図である。 [Embodiment 1]
1-3 show the additive injection region 4 in the exhaust pipe 2 of the diesel engine. FIG. 1 is a plan view, FIG. 2 is a sectional view taken along line AA, and FIG.

ディーゼルエンジンの排気ポートから排出された排気はエキゾーストマニホールドを介して実線の矢線のごとく図示左側から添加剤噴射領域４に導入されて図示右側に流れ出る。本実施の形態では添加剤噴射領域４は排気管２の曲がり部分４ａを含んでいるので、図２では左斜め上から排気が導入されて右側水平方向に排気が流れ出ている。したがって、この添加剤噴射領域４では図２において上側が曲がり部分４ａの内側に相当する。   Exhaust gas discharged from the exhaust port of the diesel engine is introduced into the additive injection region 4 from the left side of the figure as shown by the solid line through the exhaust manifold and flows out to the right side of the figure. In the present embodiment, the additive injection region 4 includes the bent portion 4a of the exhaust pipe 2. Therefore, in FIG. 2, the exhaust gas is introduced from the upper left and the exhaust gas flows out in the right horizontal direction. Accordingly, in the additive injection region 4, the upper side in FIG. 2 corresponds to the inside of the bent portion 4a.

この曲がり部分４ａの内側に添加弁６の噴射口配置位置８が設定されているが、更にここでは噴射口配置位置８は曲がり部分４ａにおける内側の管壁内面４ｂに形成した凹状空間１０内に配置されている。この凹状空間１０は、ほぼ曲がり部分４ａの中央あるいは近傍（ここではわずかに排気流下流側）に配置されているが、添加剤噴射領域４において更に下流の排気管２が直線状となっている位置に設けても良い。凹状空間１０は排気管２の管壁自身が排気管２の外側へ膨らんだ形状として形成されている。   The injection port arrangement position 8 of the addition valve 6 is set inside the bent portion 4a. Further, here, the injection port arrangement position 8 is in a concave space 10 formed on the inner tube wall inner surface 4b in the bent portion 4a. Has been placed. The concave space 10 is disposed substantially at the center or in the vicinity of the bent portion 4a (here, slightly on the downstream side of the exhaust flow), but the exhaust pipe 2 further downstream in the additive injection region 4 is linear. You may provide in a position. The concave space 10 is formed as a shape in which the pipe wall itself of the exhaust pipe 2 swells to the outside of the exhaust pipe 2.

上述した構成であることから、噴射口配置位置８に配置された添加弁６の噴射口６ａから噴射される排気浄化用添加剤、ここでは尿素水溶液１２は、二点鎖線に示すごとく凹状空間１０内に噴射されることになる。   Because of the above-described configuration, the exhaust purification additive, which is the urea aqueous solution 12 here, injected from the injection port 6a of the addition valve 6 arranged at the injection port arrangement position 8, is a concave space 10 as shown by a two-dot chain line. Will be injected inside.

凹状空間１０の排気上流側の縁部には、前面１４ａが管壁内面４ｂから斜めに立ち上がることにより管壁内面４ｂに突出している堰１４が形成されている。本実施の形態では凹状空間１０の上流側の縁部は全て堰１４が存在している。この堰１４は排気管２の管壁自身が排気管２の内側へ窪んだ形状として形成されている。尚、堰１４を形成しない形状では破線で示すごとくの位置が管壁の位置となる。   A dam 14 is formed at the edge of the concave space 10 on the exhaust upstream side so that the front surface 14a rises obliquely from the tube wall inner surface 4b and projects to the tube wall inner surface 4b. In this embodiment, weirs 14 are present at all the upstream edge of the concave space 10. The weir 14 is formed in a shape in which the tube wall itself of the exhaust pipe 2 is recessed toward the inside of the exhaust pipe 2. In the shape where the weir 14 is not formed, the position shown by the broken line is the position of the tube wall.

更にこの堰１４が存在する管壁内面４ｂに対向する管壁内面４ｃには凹部１６が形成されている。この凹部１６は排気管２の管壁自身が排気管２の外側へ膨らんだ形状として形成されている。尚、凹部１６を形成しない形状では破線で示すごとくの位置が管壁の位置となる。本実施の形態では凹部１６の窪み量は、堰１４の突出程度に対応させている。   Further, a recess 16 is formed in the tube wall inner surface 4c facing the tube wall inner surface 4b where the weir 14 exists. The recess 16 is formed in a shape in which the wall of the exhaust pipe 2 itself swells to the outside of the exhaust pipe 2. In the shape where the concave portion 16 is not formed, the position shown by the broken line is the position of the tube wall. In the present embodiment, the amount of depression of the recess 16 corresponds to the degree of protrusion of the weir 14.

このような添加剤噴射領域４にて、ディーゼルエンジンの高回転時などで排気流が高速に流れると、図４の(ａ)に示すごとく、堰１４の直前まで管路方向に沿って流れ込んだ排気流は、堰１４の前面１４ａに衝突する。このことにより排気流は曲がり部分４ａの内側から、斜めに離れるように誘導されて、曲がり部分４ａの外側に進路を変える。   In such an additive injection region 4, when the exhaust flow flows at high speed, such as when the diesel engine is rotating at high speed, it flows along the pipeline direction until just before the weir 14, as shown in FIG. The exhaust flow collides with the front surface 14 a of the weir 14. As a result, the exhaust flow is guided to be diagonally separated from the inside of the bent portion 4a, and the course is changed to the outside of the bent portion 4a.

曲がり部分４ａの外側、すなわち堰１４とは反対側の管壁内面４ｃ側には凹部１６が存在するので、排気流全体が凹状空間１０の位置に到達する直前に堰１４の前面１４ａに誘導されて円滑に外側に曲がる。このことにより排気は渦流発生を抑制した状態で実線の矢線で示すごとく凹状空間１０を飛び越えて、添加剤噴射領域４の下流側に流れる。したがって排気は凹状空間１０内に直接流れ込むことはなく、添加弁６から凹状空間１０内に噴射される尿素水溶液１２が、凹状空間１０の内面１０ａやその下流側の管壁内面４ｄに付着することが防止される。   Since the concave portion 16 exists outside the bent portion 4a, that is, on the tube wall inner surface 4c side opposite to the weir 14, the entire exhaust flow is guided to the front surface 14a of the weir 14 immediately before reaching the position of the concave space 10. Bend outward smoothly. As a result, the exhaust gas jumps over the concave space 10 and flows downstream of the additive injection region 4 as indicated by the solid arrow line in a state in which the generation of vortex is suppressed. Therefore, the exhaust gas does not flow directly into the concave space 10, and the urea aqueous solution 12 injected from the addition valve 6 into the concave space 10 adheres to the inner surface 10 a of the concave space 10 and the tube wall inner surface 4 d downstream thereof. Is prevented.

ディーゼルエンジンの低回転時などで排気流が低速である場合も、図４の(ｂ)に示すごとく、上述したごとくの堰１４と凹部１６との作用により、排気流は凹状空間１０を飛び越えて、凹状空間１０内に直接流れ込むことなく、添加剤噴射領域４の下流側に流れる。このため排気の流速が低速であっても添加弁６から凹状空間１０内に噴射される尿素水溶液１２は凹状空間１０の内面１０ａやその下流側の管壁内面４ｄに付着しない。   Even when the exhaust flow is low, such as when the diesel engine is running at a low speed, the exhaust flow jumps over the concave space 10 due to the action of the weir 14 and the concave portion 16 as described above, as shown in FIG. Without flowing directly into the concave space 10, it flows downstream of the additive injection region 4. For this reason, even when the flow rate of the exhaust gas is low, the urea aqueous solution 12 injected from the addition valve 6 into the concave space 10 does not adhere to the inner surface 10a of the concave space 10 or the tube wall inner surface 4d downstream thereof.

しかし比較例として堰１４と凹部１６とが存在しない場合には、特に排気の流速が低速である場合に、図４の(ｂ)に破線の矢線で示すごとく、排気流が凹状空間１０内に入り込んで、排気流が直接的に尿素水溶液１２に衝突して、尿素水溶液１２を凹状空間１０の内面１０ａやその下流側の管壁内面４ｄに付着させる。排気流量が少ない場合は、これに対応して尿素水溶液１２の噴射量も少ないので、この付着が顕著となる。   However, as a comparative example, when the weir 14 and the recess 16 do not exist, especially when the flow rate of the exhaust gas is low, as shown by the broken arrow in FIG. Then, the exhaust flow directly collides with the urea aqueous solution 12, and the urea aqueous solution 12 adheres to the inner surface 10a of the concave space 10 and the tube wall inner surface 4d on the downstream side thereof. When the exhaust gas flow rate is small, the amount of urea aqueous solution 12 injected correspondingly is small, and this adhesion becomes significant.

このように尿素水溶液１２が付着した状態は排気管２においては凹状空間１０側に尿素水溶液１２が偏った状態であり、付着した尿素水溶液１２あるいは水が蒸発した後の尿素微粒子が排気中に偏った状態で混合して下流の触媒まで流れることになる。しかし本実施の形態ではこのような偏りは防止される。   The state in which the urea aqueous solution 12 is attached in this way is a state in which the urea aqueous solution 12 is biased toward the concave space 10 in the exhaust pipe 2, and the urea aqueous solution 12 that has adhered or urea fine particles after water evaporation is biased in the exhaust. In this state, it is mixed and flows to the downstream catalyst. However, this bias is prevented in this embodiment.

以上説明した本実施の形態１によれば、以下の効果が得られる。
（イ）．上述したごとく、堰１４と凹部１６とにより、内燃機関の排気流量が多い場合のみでなく少ない場合にも、これに対応して少量噴射される尿素水溶液１２は排気流が入り込まない凹状空間１０内にて十分に拡散できる。特に堰１４の前面１４ａが管壁内面４ｂに対して斜めに立ち上げられていることにより、渦流発生を抑制して凹状空間１０内への排気流入り込み阻止をより確実なものとしているので、尿素水溶液１２が排気管２の内面（１０ａ，４ｄ）に直ちに付着するということがない。 According to the first embodiment described above, the following effects can be obtained.
(I). As described above, due to the weir 14 and the recess 16, not only when the exhaust flow rate of the internal combustion engine is large but also when the exhaust flow rate is small, the urea aqueous solution 12 injected in a small amount corresponds to the inside of the concave space 10 where the exhaust flow does not enter. Can be sufficiently diffused. In particular, since the front surface 14a of the weir 14 is raised obliquely with respect to the inner surface 4b of the tube wall, the generation of vortex is suppressed and the inflow of exhaust gas into the concave space 10 is more reliably prevented. The aqueous solution 12 does not immediately adhere to the inner surface (10a, 4d) of the exhaust pipe 2.

したがって尿素水溶液１２は凹状空間１０内での拡散後に、凹状空間１０と排気流との境界面から排気流中に拡散して下流の触媒（ＳＣＲ触媒）側へ運ばれることになるので、排気流量が少ない時にも尿素水溶液１２あるいはこれから派生した尿素微粒子が排気中に偏らず、均一分散が行われる。このように排気流量の多少に関わらず排気中への、排気浄化用添加剤としての尿素の均一分散を可能とすることができる。   Therefore, the urea aqueous solution 12 is diffused in the exhaust flow from the boundary surface between the concave space 10 and the exhaust flow after being diffused in the concave space 10 and is carried to the downstream catalyst (SCR catalyst) side. Even when the amount of water is small, the urea aqueous solution 12 or urea fine particles derived therefrom are not biased in the exhaust gas, and uniform dispersion is performed. In this way, it is possible to uniformly disperse urea as an exhaust purification additive into the exhaust regardless of the exhaust flow rate.

特に尿素が水溶液の形態であり、排気管２の内面（１０ａ，４ｄ）に付着し易い。このため水分の蒸発時間が必要であるが、前述したごとく添加弁６の噴射後に排気流に運ばれるまでに、拡散と共に蒸発する時間的余裕が存在する。したがって水溶液の形態でも排気流量の多少に関わらず排気中への排気浄化用添加剤の均一分散を可能とすることができる。   In particular, urea is in the form of an aqueous solution and tends to adhere to the inner surfaces (10a, 4d) of the exhaust pipe 2. For this reason, although the time for evaporating the water is necessary, there is a time margin for evaporating along with the diffusion until it is carried to the exhaust flow after the injection of the addition valve 6 as described above. Therefore, even in the form of an aqueous solution, the exhaust gas purification additive can be uniformly dispersed in the exhaust gas regardless of the exhaust flow rate.

このことにより排気流量の多少に関わらず、ディーゼルエンジンが発生するＮＯｘなどを十分に浄化できる。
（ロ）．特に堰１４が凹状空間１０の排気上流側の縁部に形成されていることから、添加弁６の噴射口６ａの配置位置周辺に排気流が入り込まない空間を十分に確保することができる。したがって排気流量の多少に関わらず排気中への排気浄化用添加剤の均一分散効果をより高めることができる。 This makes it possible to sufficiently purify NOx generated by the diesel engine regardless of the exhaust flow rate.
(B). In particular, since the weir 14 is formed at the edge of the concave space 10 on the upstream side of the exhaust, it is possible to sufficiently secure a space where the exhaust flow does not enter the vicinity of the position where the injection port 6a of the addition valve 6 is disposed. Therefore, the effect of uniformly dispersing the exhaust gas purification additive into the exhaust gas can be further enhanced regardless of the flow rate of the exhaust gas.

（ハ）．凹状空間１０は、排気管２の曲がり部分４ａにおける内側、又は曲がり部分４ａの近傍における内側に形成されている。このように凹状空間１０が配置されていると、排気管２の設計上や凹状空間１０の成形上などの制約から、凹状空間１０が排気流の入り込み易くなるような配置や形状となる場合がある。しかし、このような場合にも前述したごとくの堰１４及び凹部１６を設けることで、容易に凹状空間１０への排気流の入り込みをしにくくできる。したがって、上述した制約を受けても、排気流量の多少に関わらず排気中への排気浄化用添加剤の均一分散を可能とすることができる。   (C). The recessed space 10 is formed inside the bent portion 4a of the exhaust pipe 2 or inside the vicinity of the bent portion 4a. When the concave space 10 is arranged in this way, the concave space 10 may be arranged or shaped so that the exhaust flow can easily enter due to restrictions on the design of the exhaust pipe 2 and the molding of the concave space 10. is there. However, even in such a case, by providing the weir 14 and the concave portion 16 as described above, it is difficult to easily enter the exhaust flow into the concave space 10. Therefore, even under the above-described restrictions, it is possible to uniformly disperse the exhaust purification additive into the exhaust regardless of the amount of exhaust flow.

（ニ）．堰１４は排気管２の管壁自身が排気管２の内側へ窪んだ形状として形成され 、凹部１６及び凹状空間１０は排気管２の管壁自身が排気管２の外側へ膨らんだ形状として形成されている。したがって管壁以外の特別な部材を配置しなくてもこれらを形成でき、排気管構造の簡素化が可能となり、かつ軽量化にも貢献できる。   (D). The weir 14 is formed as a shape in which the tube wall of the exhaust pipe 2 is recessed toward the inside of the exhaust pipe 2, and the concave portion 16 and the recessed space 10 are formed as a shape in which the tube wall of the exhaust pipe 2 is swelled outside the exhaust pipe 2. Has been. Therefore, these can be formed without arranging any special member other than the pipe wall, the exhaust pipe structure can be simplified, and the weight can be reduced.

［実施の形態２］
図５の要部斜視図に本実施の形態の排気管１０２における添加剤噴射領域１０４の構成を示す。本実施の形態では、堰１１４の両端が噴射口配置位置１０８の両側部分に延長されている。すなわち凹状空間１１０の排気上流側の縁部に形成した前方堰１１４ａと、凹状空間１１０の両側に形成した側方堰１１４ｂとからなる。図５では噴射口配置位置１０８に隠れているが、噴射口配置位置１０８の反対側にも側方堰１１４ｂが存在する。 [Embodiment 2]
The configuration of the additive injection region 104 in the exhaust pipe 102 of the present embodiment is shown in the perspective view of the main part in FIG. In the present embodiment, both ends of the weir 114 are extended to both side portions of the injection port arrangement position 108. That is, it consists of a front weir 114 a formed at the edge of the recessed space 110 on the exhaust upstream side and side weirs 114 b formed on both sides of the recessed space 110. In FIG. 5, although hidden behind the injection port arrangement position 108, there is a side dam 114 b on the opposite side of the injection port arrangement position 108.

凹部１１６等の他の構成は前記実施の形態１と同じである。
以上説明した本実施の形態２によれば、以下の効果が得られる。
（イ）．前記実施の形態１の効果を生じると共に、側方堰１１４ｂが前方堰１１４ａの両側に連続して形成されているため、凹状空間１１０の両側からの排気流の入り込みを阻止して、排気流を噴射口配置位置１０８の周辺に入り込まないようにする作用を強めることができる。 Other configurations such as the recess 116 are the same as those in the first embodiment.
According to the second embodiment described above, the following effects can be obtained.
(I). In addition to the effects of the first embodiment, the side weirs 114b are formed continuously on both sides of the front weir 114a, so that the exhaust flow from both sides of the concave space 110 is prevented from entering and the exhaust flow is reduced. It is possible to enhance the effect of preventing the vicinity of the injection port arrangement position 108 from entering.

［実施の形態３］
図６の要部斜視図に本実施の形態の排気管２０２における添加剤噴射領域２０４の構成を示す。本実施の形態では、堰２１４は前記実施の形態２の場合よりも更に延長されて凹状空間２１０の全周の縁部に形成されている。図６では噴射口配置位置２０８に隠れているが、噴射口配置位置２０８の反対側にも堰２１４が存在する。 [Embodiment 3]
The configuration of the additive injection region 204 in the exhaust pipe 202 of the present embodiment is shown in the perspective view of the main part in FIG. In the present embodiment, the weir 214 is further extended than the case of the second embodiment, and is formed at the edge of the entire circumference of the concave space 210. In FIG. 6, although hidden behind the injection port arrangement position 208, there is a weir 214 on the opposite side of the injection port arrangement position 208.

凹部２１６等の他の構成は前記実施の形態１と同じである。
以上説明した本実施の形態３によれば、以下の効果が得られる。
（イ）．前記実施の形態２の効果を生じると共に、堰２１４が凹状空間２１０の全周を囲んでいるため、噴射口配置位置２０８周辺への排気流の入り込み阻止をより確実なものにできる。 Other configurations such as the recess 216 are the same as those in the first embodiment.
According to the third embodiment described above, the following effects can be obtained.
(I). In addition to the effects of the second embodiment, the weir 214 surrounds the entire circumference of the concave space 210, so that it is possible to more reliably prevent the exhaust flow from entering the periphery of the injection port arrangement position 208.

［実施の形態４］
図７の(ａ)に示す縦断面図に、本実施の形態の排気管３０２における添加剤噴射領域３０４の構成を示す。本実施の形態では、噴射口配置位置３０８には、凹状空間は設けられておらず、添加弁３０６は図示するごとく噴射口３０６ａから排気管２内部に排気浄化用添加剤水溶液(ここでは尿素水溶液)３１２を噴射するように配置されている。この噴射口配置位置３０８の排気上流側には堰３１４が設けられている。他の構成は前記実施の形態１と同じである。 [Embodiment 4]
The configuration of the additive injection region 304 in the exhaust pipe 302 of the present embodiment is shown in the longitudinal sectional view shown in FIG. In the present embodiment, the injection port arrangement position 308 is not provided with a concave space, and the addition valve 306 has an exhaust purification additive aqueous solution (here, urea aqueous solution) from the injection port 306a into the exhaust pipe 2 as shown in the figure. ) 312 is sprayed. A weir 314 is provided on the exhaust upstream side of the injection port arrangement position 308. Other configurations are the same as those of the first embodiment.

すなわち添加剤噴射領域３０４の曲がり部分３０４ａの内側に、添加弁３０６の噴射口配置位置３０８が設けられている。この噴射口配置位置３０８は、ほぼ曲がり部分３０４ａの中央あるいはわずかに排気流下流側であるが、更に下流の排気管３０２が直線状となっている位置に設けても良い。   That is, the injection port arrangement position 308 of the addition valve 306 is provided inside the bent portion 304 a of the additive injection region 304. The injection port arrangement position 308 is substantially at the center of the bent portion 304a or slightly downstream of the exhaust flow, but may be provided at a position where the downstream exhaust pipe 302 is linear.

ここで噴射口配置位置３０８に設けられた添加弁３０６の噴射口３０６ａから噴射される排気浄化用添加剤水溶液３１２は二点鎖線に示すごとく噴射口配置位置３０８における排気管３０２内の空間３１０に噴射される。   Here, the exhaust gas purification additive aqueous solution 312 injected from the injection port 306a of the addition valve 306 provided at the injection port arrangement position 308 enters the space 310 in the exhaust pipe 302 at the injection port arrangement position 308 as shown by a two-dot chain line. Be injected.

噴射口配置位置３０８の排気上流側には、前面３１４ａが管壁内面３０４ｂから斜めに立ち上がることにより管壁内面３０４ｂに突出している堰３１４が形成されている。この堰３１４は排気管３０２の管壁自身が排気管３０２の内側へ窪んだ形状として形成されている。尚、堰３１４を形成しない形状では破線で示すごとくの位置に管壁が形成される。   A weir 314 is formed on the exhaust upstream side of the injection port arrangement position 308 so that the front surface 314a rises obliquely from the tube wall inner surface 304b and projects to the tube wall inner surface 304b. The weir 314 is formed in a shape in which the pipe wall itself of the exhaust pipe 302 is recessed toward the inside of the exhaust pipe 302. In the shape where the weir 314 is not formed, a tube wall is formed at a position as indicated by a broken line.

更にこの堰３１４が存在する管壁内面３０４ｂに対向する管壁内面３０４ｃには凹部３１６が形成されている。この凹部３１６は排気管３０２の管壁自身が排気管３０２の外側へ膨らんだ形状として形成されている。尚、凹部３１６を形成しない形状では破線で示すごとくの位置に管壁が形成される。本実施の形態では凹部３１６の窪み量は、堰３１４の突出程度に対応させている。   Further, a recess 316 is formed in the tube wall inner surface 304c opposite to the tube wall inner surface 304b where the weir 314 exists. The recess 316 is formed in a shape in which the tube wall itself of the exhaust pipe 302 bulges outside the exhaust pipe 302. In addition, in the shape which does not form the recessed part 316, a tube wall is formed in the position as shown with a broken line. In the present embodiment, the amount of depression of the recess 316 corresponds to the degree of protrusion of the weir 314.

このような添加剤噴射領域３０４にて、ディーゼルエンジンの高回転時などで排気流が高速に流れると、実線の矢線にて示すごとく、堰３１４の直前まで管路方向に沿って流れ込んだ排気流は、堰３１４の前面３１４ａに衝突する。このことにより排気流は曲がり部分３０４ａの内側から、斜めに離れるように誘導されて、曲がり部分３０４ａの外側に進路を変える。   In such an additive injection region 304, when the exhaust flow flows at high speed, such as when the diesel engine is rotating at high speed, as indicated by the solid line arrow, the exhaust that has flowed in the pipeline direction until just before the weir 314 The flow impinges on the front surface 314 a of the weir 314. As a result, the exhaust flow is guided to be diagonally separated from the inside of the bent portion 304a, and the course of the exhaust flow is changed to the outside of the bent portion 304a.

曲がり部分３０４ａの外側、すなわち堰３１４とは反対側の管壁内面３０４ｃ側には凹部３１６が存在するので、排気流全体が噴射口配置位置３０８における空間３１０の位置に到達する直前に堰３１４の前面３１４ａに誘導されて円滑に外側に曲がる。このことにより排気は渦流発生を抑制した状態で実線の矢線で示すごとく空間３１０を飛び越えて、添加剤噴射領域３０４の下流側に流れる。したがって排気は噴射口配置位置３０８に直接流れ込むことはなく、添加弁３０６から空間３１０内に噴射される排気浄化用添加剤水溶液３１２が、噴射口配置位置３０８の管壁内面３０８ａやその下流側の管壁内面３０４ｄに付着することが防止される。このことはディーゼルエンジンの排気流が低速でも同じである。   Since there is a recess 316 outside the bent portion 304a, that is, on the tube wall inner surface 304c side opposite to the weir 314, the entire exhaust flow immediately before reaching the position of the space 310 at the injection port arrangement position 308. It is guided to the front surface 314a and smoothly bends outward. As a result, the exhaust gas jumps over the space 310 and flows downstream of the additive injection region 304 as indicated by the solid arrow in a state in which the generation of vortex is suppressed. Therefore, the exhaust gas does not flow directly into the injection port arrangement position 308, and the exhaust gas purification additive aqueous solution 312 injected into the space 310 from the addition valve 306 is added to the pipe wall inner surface 308 a at the injection port arrangement position 308 or downstream thereof. Adhering to the tube wall inner surface 304d is prevented. This is the same even when the exhaust flow of the diesel engine is low.

しかし比較例として破線で示したごとく堰３１４と凹部３１６とが存在しない場合には、特に排気流が低速である場合には排気流が直接的に排気浄化用添加剤水溶液３１２に衝突して噴射口配置位置３０８の管壁内面３０８ａやその下流側の管壁内面３０４ｄに排気浄化用添加剤水溶液３１２を付着させる。この付着された状態は排気管３０２においては噴射口配置位置３０８側に偏っており、付着された排気浄化用添加剤水溶液３１２あるいは水が蒸発した後の排気浄化用添加剤微粒子が排気中に偏った状態で混合して、下流の触媒まで流れることになる。しかし本実施の形態ではこのような偏りは防止される。したがって凹状空間は存在しないが、他の部分については前記実施の形態１の効果を生じる。   However, as shown by a broken line as a comparative example, when the weir 314 and the recess 316 do not exist, particularly when the exhaust flow is low speed, the exhaust flow directly collides with the exhaust gas purification additive aqueous solution 312 and is injected. The exhaust gas purification additive aqueous solution 312 is attached to the tube wall inner surface 308a at the mouth arrangement position 308 and the tube wall inner surface 304d on the downstream side. This attached state is biased toward the injection port arrangement position 308 in the exhaust pipe 302, and the adhered exhaust purification additive aqueous solution 312 or the exhaust purification additive fine particles after the water has evaporated is biased into the exhaust. In this state, they are mixed and flow to the downstream catalyst. However, this bias is prevented in this embodiment. Therefore, although there is no concave space, the effects of the first embodiment are produced for the other portions.

図７の(ｂ)の縦断面図に示す排気管４０２は、添加剤噴射領域４０４において噴射口配置位置４０８の排気上流側に堰４１４を設けると共に、その堰４１４の両端が噴射口配置位置４０８の両側部分に延長されている。したがって、図７の(ａ)に比較して、噴射口配置位置４０８での排気管４０２内の空間４１０に対する両側からの排気流の入り込みを阻止して、排気流を噴射口配置位置４０８の周辺に入り込まないようにする作用を強めることができる。   The exhaust pipe 402 shown in the longitudinal sectional view of FIG. 7B is provided with a weir 414 on the exhaust upstream side of the injection port arrangement position 408 in the additive injection region 404, and both ends of the weir 414 are at the injection port arrangement position 408. It is extended on both sides. Therefore, in comparison with FIG. 7A, the exhaust flow is prevented from entering from the both sides into the space 410 in the exhaust pipe 402 at the injection port arrangement position 408, and the exhaust flow is made around the injection port arrangement position 408. It can strengthen the action to prevent it from entering.

図７の(ｃ)の縦断面図に示す排気管５０２は、添加剤噴射領域５０４において噴射口配置位置５０８の全周を囲んで堰５１４を設けている。このことにより図７の(ａ)，(ｂ)に比較して噴射口配置位置５０８の周辺への排気流の入り込み阻止をより確実なものとできる。   The exhaust pipe 502 shown in the longitudinal sectional view of FIG. 7C is provided with a weir 514 surrounding the entire circumference of the injection port arrangement position 508 in the additive injection region 504. Accordingly, it is possible to more reliably prevent the exhaust flow from entering the periphery of the injection port arrangement position 508 as compared with FIGS. 7 (a) and 7 (b).

［その他の実施の形態］
（ａ）．前記実施の形態においてはディーゼルエンジンの排気管での例を示したが、ガソリンエンジンにおいても排気浄化処理するために排気管で添加剤を噴射する場合にも適用でき、同様な効果を生じさせることができる。 [Other embodiments]
(A). In the above embodiment, an example of the exhaust pipe of a diesel engine has been shown. However, the present invention can also be applied to a gasoline engine when an additive is injected through an exhaust pipe in order to purify exhaust, and the same effect can be produced. Can do.

（ｂ）．更に添加剤の均一拡散性を高めるために、添加剤噴射領域の直下に、格子状、網状などの分散板を設けても良い。
（ｃ）．添加剤としては尿素水溶液を挙げたが、ＮＯｘ吸蔵還元型触媒の場合は炭化水素などの還元剤を添加剤として用いるが、この場合にも本発明を適用することにより排気流量の多少に関わらず排気中への添加剤の均一分散が可能となる。これ以外の他の添加剤の場合も同様な効果を生じさせることができる。 (B). Further, in order to improve the uniform diffusibility of the additive, a grid-like or mesh-like dispersion plate may be provided immediately below the additive injection region.
(C). As an additive, an aqueous urea solution is mentioned, but in the case of a NOx occlusion reduction type catalyst, a reducing agent such as a hydrocarbon is used as an additive. In this case, the present invention can be applied regardless of the amount of exhaust flow. It is possible to uniformly disperse the additive in the exhaust gas. Similar effects can be produced in the case of other additives.

（ｄ）．図６及び図７の(ｃ)の実施例では、堰は噴射口配置位置の周囲を囲んで全周形成したが、噴射口配置位置の排気上流側と排気下流側との２ヶ所として、排気流と平行な部分の堰は設けない構成でも良い。このように堰を排気上流側と共に下流側にも設けることにより、渦流なども含めて、より確実に排気流を噴射口配置位置の周辺に入り込まないようにすることができる。   (D). In the embodiment of FIG. 6 and FIG. 7C, the weir is formed around the periphery of the injection port arrangement position, but the exhaust is provided as two locations on the exhaust upstream side and the exhaust downstream side of the injection port arrangement position. A configuration without a weir in a portion parallel to the flow may be used. By providing the weirs on the downstream side as well as the exhaust upstream side in this way, it is possible to prevent the exhaust flow from entering the periphery of the injection port arrangement position more reliably including the vortex flow.

２…排気管、４…添加剤噴射領域、４ａ…曲がり部分、４ｂ，４ｃ，４ｄ…管壁内面、６…添加弁、６ａ…噴射口、８…噴射口配置位置、１０…凹状空間、１０ａ…内面、１２…尿素水溶液、１４…堰、１４ａ…前面、１６…凹部、１０２…排気管、１０４…添加剤噴射領域、１０８…噴射口配置位置、１１０…凹状空間、１１４…堰、１１４ａ…前方堰、１１４ｂ…側方堰、１１６…凹部、２０２…排気管、２０４…添加剤噴射領域、２０８…噴射口配置位置、２１０…凹状空間、２１４…堰、２１６…凹部、３０２…排気管、３０４…添加剤噴射領域、３０４ａ…曲がり部分、３０４ｂ，３０４ｃ，３０４ｄ…管壁内面、３０６…添加弁、３０６ａ…噴射口、３０８…噴射口配置位置、３０８ａ…管壁内面、３１０…空間、３１２…排気浄化用添加剤水溶液、３１４…堰、３１４ａ…前面、３１６…凹部、４０２…排気管、４０４…添加剤噴射領域、４０８…噴射口配置位置、４１０…空間、４１４…堰、５０２…排気管、５０４…添加剤噴射領域、５０８…噴射口配置位置、５１４…堰。   2 ... exhaust pipe, 4 ... additive injection region, 4a ... bent portion, 4b, 4c, 4d ... pipe wall inner surface, 6 ... addition valve, 6a ... injection port, 8 ... injection port arrangement position, 10 ... concave space, 10a ... inner surface, 12 ... urea aqueous solution, 14 ... weir, 14a ... front face, 16 ... recess, 102 ... exhaust pipe, 104 ... additive injection region, 108 ... injection port arrangement position, 110 ... concave space, 114 ... weir, 114a ... Front weir, 114b ... Side weir, 116 ... Recess, 202 ... Exhaust pipe, 204 ... Additive injection area, 208 ... Injection port arrangement position, 210 ... Recessed space, 214 ... Weir, 216 ... Recess, 302 ... Exhaust pipe, 304 ... Additive injection region, 304a ... Curved portion, 304b, 304c, 304d ... Tube wall inner surface, 306 ... Addition valve, 306a ... Injection port, 308 ... Injection port arrangement position, 308a ... Tube wall inner surface, 310 ... Space, 312 …exhaust Additive aqueous solution for chemicalization, 314 ... weir, 314a ... front surface, 316 ... recess, 402 ... exhaust pipe, 404 ... additive injection region, 408 ... injection port arrangement position, 410 ... space, 414 ... weir, 502 ... exhaust pipe, 504 ... additive injection region, 508 ... injection port arrangement position, 514 ... weir.

Claims (11)

排気管内に添加弁から添加剤を噴射する内燃機関の排気管構造であって、
前記添加弁の噴射口配置位置の排気上流側に管壁内面から突出し、排気の流動方向に対向する前面が管壁内面に対して斜めに立ち上げられた堰と、
前記堰が設けられた管壁内面とは対向する管壁内面に設けた凹部とを備え、
前記堰と共に、前記噴射口配置位置の排気下流側にて管壁内面から突出した堰を設けて、排気上流側と下流側とで前記噴射口配置位置を２つの堰にて挟んでいる
ことを特徴とする内燃機関の排気管構造。 An exhaust pipe structure of an internal combustion engine that injects an additive from an addition valve into the exhaust pipe,
A weir that protrudes from the inner surface of the pipe wall to the exhaust upstream side of the injection valve arrangement position of the addition valve, and a front surface that faces the flow direction of the exhaust is obliquely raised with respect to the inner surface of the pipe wall;
A concave portion provided on the inner surface of the tube wall opposite to the inner surface of the tube wall provided with the weir,
Along with the weir, a weir projecting from the inner surface of the pipe wall on the exhaust downstream side of the injection port arrangement position is provided, and the injection port arrangement position is sandwiched between two weirs on the exhaust upstream side and the downstream side. An exhaust pipe structure of an internal combustion engine characterized by the above. 排気管内に添加弁から添加剤を噴射する内燃機関の排気管構造であって、
前記添加弁の噴射口配置位置の排気上流側に管壁内面から突出し、排気の流動方向に対向する前面が管壁内面に対して斜めに立ち上げられた堰と、
前記堰が設けられた管壁内面とは対向する管壁内面に設けた凹部とを備え、
前記噴射口配置位置は、排気管の曲がり部分における内側、又は排気管の曲がり部分の近傍における内側に配置されている
ことを特徴とする内燃機関の排気管構造。 An exhaust pipe structure of an internal combustion engine that injects an additive from an addition valve into the exhaust pipe,
A weir that protrudes from the inner surface of the pipe wall to the exhaust upstream side of the injection valve arrangement position of the addition valve, and a front surface that faces the flow direction of the exhaust is obliquely raised with respect to the inner surface of the pipe wall;
A concave portion provided on the inner surface of the tube wall opposite to the inner surface of the tube wall provided with the weir,
2. The exhaust pipe structure of an internal combustion engine, wherein the injection port is disposed at an inner side in a bent portion of the exhaust pipe or an inner side in the vicinity of the bent portion of the exhaust pipe. 排気管内に添加弁から添加剤を噴射する内燃機関の排気管構造であって、
前記添加弁の噴射口配置位置の排気上流側に管壁内面から突出し、排気の流動方向に対向する前面が管壁内面に対して斜めに立ち上げられた堰と、
前記堰が設けられた管壁内面とは対向する管壁内面に設けた凹部とを備え、
前記噴射口配置位置は、管壁内面に形成した凹状空間内に配置されていると共に、前記堰は、前記凹状空間の排気上流側の縁部に形成され、当該堰と共に、前記凹状空間の排気下流側の縁部に堰を設けて、排気上流側と下流側とで前記凹状空間を２つの堰にて挟んでいる
ことを特徴とする内燃機関の排気管構造。 An exhaust pipe structure of an internal combustion engine that injects an additive from an addition valve into the exhaust pipe,
A weir that protrudes from the inner surface of the pipe wall to the exhaust upstream side of the injection valve arrangement position of the addition valve, and a front surface that faces the flow direction of the exhaust is obliquely raised with respect to the inner surface of the pipe wall;
A concave portion provided on the inner surface of the tube wall opposite to the inner surface of the tube wall provided with the weir,
The injection port is disposed in a concave space formed on the inner surface of the tube wall, and the weir is formed at an edge of the concave space on the upstream side of the exhaust, and together with the weir, the exhaust of the concave space An exhaust pipe structure for an internal combustion engine, wherein a weir is provided at an edge on the downstream side, and the concave space is sandwiched between two weirs on the upstream side and the downstream side of the exhaust. 排気管内に添加弁から添加剤を噴射する内燃機関の排気管構造であって、
前記添加弁の噴射口配置位置の排気上流側に管壁内面から突出し、排気の流動方向に対向する前面が管壁内面に対して斜めに立ち上げられた堰と、
前記堰が設けられた管壁内面とは対向する管壁内面に設けた凹部とを備え、
前記噴射口配置位置は、管壁内面に形成した凹状空間内に配置されていると共に、前記堰は、前記凹状空間の排気上流側の縁部に形成され、
前記凹状空間は、排気管の曲がり部分における内側、又は排気管の曲がり部分の近傍における内側に形成されている
ことを特徴とする内燃機関の排気管構造。 An exhaust pipe structure of an internal combustion engine that injects an additive from an addition valve into the exhaust pipe,
A weir that protrudes from the inner surface of the pipe wall to the exhaust upstream side of the injection valve arrangement position of the addition valve, and a front surface that faces the flow direction of the exhaust is obliquely raised with respect to the inner surface of the pipe wall;
A concave portion provided on the inner surface of the tube wall opposite to the inner surface of the tube wall provided with the weir,
The injection port arrangement position is arranged in a concave space formed on the inner surface of the tube wall, and the weir is formed on an edge of the concave space on the exhaust upstream side,
The exhaust pipe structure of an internal combustion engine, wherein the concave space is formed on an inner side in a bent portion of the exhaust pipe or on an inner side in the vicinity of the bent portion of the exhaust pipe. 請求項３又は４に記載の内燃機関の排気管構造において、前記凹状空間は、管壁自身が排気管外側へ膨らんだ形状として形成されていることを特徴とする内燃機関の排気管構造。 The exhaust pipe structure for an internal combustion engine according to claim 3 or 4 , wherein the concave space is formed in a shape in which the tube wall itself swells to the outside of the exhaust pipe. 請求項１〜５のいずれか一項に記載の内燃機関の排気管構造において、前記堰は、管壁自身が排気管内側へ窪んだ形状として形成されていることを特徴とする内燃機関の排気管構造。 The exhaust pipe structure for an internal combustion engine according to any one of claims 1 to 5 , wherein the weir is formed in a shape in which the pipe wall itself is recessed toward the inside of the exhaust pipe. Tube structure. 請求項１〜６のいずれか一項に記載の内燃機関の排気管構造において、前記凹部は、管壁自身が排気管外側へ膨らんだ形状として形成されていることを特徴とする内燃機関の排気管構造。 The exhaust pipe structure for an internal combustion engine according to any one of claims 1 to 6 , wherein the recess is formed in a shape in which the pipe wall itself swells to the outside of the exhaust pipe. Tube structure. 請求項１〜７のいずれか一項に記載の内燃機関の排気管構造において、前記添加剤は排気浄化用添加剤であることを特徴とする内燃機関の排気管構造。 The exhaust pipe structure of the internal combustion engine according to any one of claims 1 to 7 , wherein the additive is an additive for exhaust gas purification. 請求項８に記載の内燃機関の排気管構造において、前記添加剤は水溶液の形態であることを特徴とする内燃機関の排気管構造。 The exhaust pipe structure for an internal combustion engine according to claim 8 , wherein the additive is in the form of an aqueous solution. 請求項９に記載の内燃機関の排気管構造において、前記添加剤は尿素水溶液であることを特徴とする内燃機関の排気管構造。 The exhaust pipe structure for an internal combustion engine according to claim 9 , wherein the additive is an aqueous urea solution. 請求項１〜１０のいずれか一項に記載の内燃機関の排気管構造において、前記内燃機関はディーゼルエンジンであることを特徴とする内燃機関の排気管構造。 The exhaust pipe structure for an internal combustion engine according to any one of claims 1 to 10 , wherein the internal combustion engine is a diesel engine.
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