JP2005214171A - Engine exhaust emission control device - Google Patents

Engine exhaust emission control device Download PDF

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JP2005214171A
JP2005214171A JP2004025754A JP2004025754A JP2005214171A JP 2005214171 A JP2005214171 A JP 2005214171A JP 2004025754 A JP2004025754 A JP 2004025754A JP 2004025754 A JP2004025754 A JP 2004025754A JP 2005214171 A JP2005214171 A JP 2005214171A
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exhaust
reducing agent
injection nozzle
engine
pipe
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JP4137807B2 (en
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Masanobu Hirata
公信 平田
Nobuhiko Masaki
信彦 正木
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UD Trucks Corp
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UD Trucks Corp
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Priority to JP2004025754A priority Critical patent/JP4137807B2/en
Priority to EP05709649A priority patent/EP1712754A4/en
Priority to PCT/JP2005/001529 priority patent/WO2005073527A1/en
Publication of JP2005214171A publication Critical patent/JP2005214171A/en
Priority to US11/495,636 priority patent/US8011176B2/en
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Publication of JP4137807B2 publication Critical patent/JP4137807B2/en
Priority to US12/954,343 priority patent/US20110067385A1/en
Priority to US12/954,337 priority patent/US8578703B2/en
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

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  • Exhaust Gas Treatment By Means Of Catalyst (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine exhaust emission control device for purifying exhaust gas by using reducing agent for reducing and removing nitrogen oxide (NOx) in the exhaust gas from an engine mounted on a vehicle, while promoting the diffusion and mixture of the reducing agent injected and supplied to an exhaust system for the engine and preventing the deposition of the reducing agent in an injection nozzle. <P>SOLUTION: The engine exhaust emission control device comprises a reduction catalyst 4 arranged in an exhaust pipe 3 of the engine 1 for reducing and purifying the nitrogen oxide in the exhaust gas with the reducing agent 12 and the injection nozzle 5 mounted on the exhaust upstream side of the reduction catalyst 4 via the exhaust pipe 3 for injecting and supplying the reducing agent 12 stored in a storage tank 9 into the exhaust gas. The injection nozzle 5 is mounted on the side of a bottom wall portion of the exhaust pipe 3 with its front end upward in a vertical direction so that the reducing agent 12 is injected upward from a nozzle hole 5a at the front end. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、エンジンの排気系に噴射ノズルから還元剤を噴射供給し、排気中の窒素酸化物を還元触媒で還元除去して排気を浄化するエンジンの排気浄化装置に関し、特に、上記排気系の配管の底壁部側に取り付けられた噴射ノズルより還元剤を下方から上方に向けて噴射供給して該還元剤を排気中で拡散、混合させると共に、上記噴射ノズルに還元剤が析出するのを防止するエンジンの排気浄化装置に関する。   The present invention relates to an engine exhaust purification device that purifies exhaust by injecting and supplying a reducing agent from an injection nozzle to an exhaust system of an engine and reducing and removing nitrogen oxides in the exhaust with a reduction catalyst. The reducing agent is injected and supplied from below to above from the injection nozzle attached to the bottom wall side of the pipe to diffuse and mix the reducing agent in the exhaust, and the reducing agent is deposited on the injection nozzle. The present invention relates to an exhaust emission control device for an engine.

従来から、車両に搭載されたディーゼルエンジンや、ガソリンエンジン等から排出された排気中の窒素酸化物（以下「ＮＯｘ」という。）を還元剤により還元除去して排気を浄化する装置が提案されている。この排気浄化装置は、エンジンの排気系に配設された還元触媒と、エンジンの排気管内にて上記還元触媒の排気上流側に取り付けられ、排気中に還元剤を噴射供給する噴射ノズルとを備えて成り、この噴射ノズルから排気中に還元剤を噴射供給することにより、排気中のＮＯｘと還元剤とを触媒中で還元反応させ、ＮＯｘを無害成分に浄化処理するようになっていた。このような還元剤としては、加水分解してアンモニアを容易に発生する尿素等の水溶液やアンモニア水溶液、その他の還元剤水溶液が用いられている。上記還元剤は、貯蔵タンク内に常温で液体状態に貯蔵され、噴射ノズルから必要量が噴射供給されるようになっていた。そして、エンジンの運転状況、例えばＮＯｘ排気量や排気温度に応じて、上記噴射ノズルから噴射供給される還元剤の量をコントロールすることで、エンジンの排気浄化の制御を行うようになっていた（例えば、特許文献１参照。）。
特開２０００−２７６２７号公報 Conventionally, there has been proposed an apparatus for purifying exhaust gas by reducing and removing nitrogen oxides (hereinafter referred to as “NOx”) in exhaust gas discharged from a diesel engine, a gasoline engine, or the like mounted on a vehicle with a reducing agent. Yes. This exhaust purification device includes a reduction catalyst disposed in an exhaust system of an engine, and an injection nozzle that is attached to the exhaust upstream side of the reduction catalyst in an exhaust pipe of the engine and that injects a reducing agent into the exhaust. Thus, by supplying the reducing agent into the exhaust gas from the injection nozzle, NOx and the reducing agent in the exhaust gas are reduced in the catalyst to purify NOx into harmless components. As such a reducing agent, an aqueous solution of urea or the like that easily generates ammonia by hydrolysis, an aqueous ammonia solution, or another aqueous reducing agent solution is used. The reducing agent is stored in a liquid state at room temperature in a storage tank, and a required amount is jetted and supplied from a jet nozzle. The engine exhaust purification control is performed by controlling the amount of reducing agent injected and supplied from the injection nozzle in accordance with the operating state of the engine, for example, the NOx exhaust amount and the exhaust temperature ( For example, see Patent Document 1.)
JP 2000-27627 A

しかし、上記特許文献１に記載のエンジンの排気浄化装置においては、図５に示すように、エンジンの排気系に還元剤１２を噴射供給する噴射ノズル５は、フランジ７を用いてエンジンの排気管３の上壁部側に取り付けられており、その先端部の噴孔５ａが排気の下流側に向けられていた。そのため、噴射ノズル５の噴孔５ａから排気中に噴射供給された還元剤１２は、排気中で十分に拡散されず、排気流に流されてそのまま下流側に運ばれるので、排気に効率的に混合されないことがあった。その結果、排気中のＮＯｘの還元反応が触媒中で進行せずに、ＮＯｘがそのまま排出されるようになり、所期の排気浄化性能を得られなくなるおそれがあった。   However, in the engine exhaust gas purification apparatus described in Patent Document 1, the injection nozzle 5 for supplying the reducing agent 12 to the engine exhaust system is provided with a flange 7 as shown in FIG. 3 is attached to the upper wall portion side, and the nozzle hole 5a at the tip thereof is directed to the downstream side of the exhaust gas. Therefore, the reducing agent 12 injected and supplied into the exhaust gas from the injection hole 5a of the injection nozzle 5 is not sufficiently diffused in the exhaust gas, but flows into the exhaust flow and is carried downstream as it is. Sometimes it was not mixed. As a result, the reduction reaction of NOx in the exhaust gas does not proceed in the catalyst, but NOx is discharged as it is, so that the desired exhaust gas purification performance may not be obtained.

このような不具合を回避するために、上記噴射ノズル５から排気中に必要量以上の還元剤１２が噴射供給されることがあった。この場合には、還元剤１２の全てが還元反応に寄与せずに、そのまま排出されることがあり、ランニングコストが上昇するという問題点があった。また、上記噴射ノズル５から必要量以上の還元剤１２が噴射供給されると、その噴孔５ａの周辺に還元剤が析出し、噴孔５ａの目詰まりが発生することもあった。その結果として、エンジンの排気管３内に十分な量の還元剤１２が噴射供給されず、ＮＯｘの大量放出状態を招くおそれがあった。   In order to avoid such a problem, a reductant 12 exceeding the necessary amount may be injected and supplied from the injection nozzle 5 into the exhaust gas. In this case, all of the reducing agent 12 does not contribute to the reduction reaction and may be discharged as it is, resulting in an increase in running cost. In addition, when a necessary amount or more of the reducing agent 12 is supplied from the injection nozzle 5, the reducing agent is deposited around the nozzle hole 5a, and the nozzle hole 5a may be clogged. As a result, a sufficient amount of the reducing agent 12 is not injected and supplied into the exhaust pipe 3 of the engine, which may cause a large amount of NOx emission.

また、上記噴射ノズル５は、その噴孔５ａを下方に向けて取り付けられていたので、該噴射ノズル５から噴射された還元剤１２が上記排気管３内の底壁に付着する範囲Ａ1において、還元剤１２が析出することがあった。さらに、上記噴射ノズル５の噴孔５ａが下向きに取り付けられていたので、還元剤１２の噴射供給を停止したときに、噴射ノズル５内に残留した還元剤１２が噴孔５ａに垂れてきて目詰まりすることがあり、上述のように、エンジンの排気管３内に十分な量の還元剤１２が噴射供給されず、ＮＯｘの大量放出状態を招くおそれがあった。 Further, since the injection nozzle 5 is mounted with its injection hole 5a facing downward, in the range A 1 where the reducing agent 12 injected from the injection nozzle 5 adheres to the bottom wall in the exhaust pipe 3. The reducing agent 12 sometimes precipitated. Further, since the injection hole 5a of the injection nozzle 5 is attached downward, when the supply of the reducing agent 12 is stopped, the reducing agent 12 remaining in the injection nozzle 5 drops into the injection hole 5a. As described above, there is a possibility that a sufficient amount of the reducing agent 12 is not injected and supplied into the exhaust pipe 3 of the engine, resulting in a large release state of NOx.

この他、燃料である軽油やガソリン、もしくはアルコール類等を還元剤として用いる場合においても同様に、還元剤の拡散、混合等の不良によって、排気浄化率の低下や、過剰に供給した分の還元剤の排出、或いは還元剤の析出により排気管内に汚れなどが付着する可能性があった。   In addition, in the case of using light oil, gasoline, or alcohol as a reducing agent, the exhaust purification rate is reduced due to the diffusion or mixing of the reducing agent, or the excess supply is reduced. There is a possibility that dirt or the like may adhere to the exhaust pipe due to discharge of the agent or deposition of the reducing agent.

そこで、本発明は、このような問題点に対処し、エンジンの排気系に還元剤を噴射供給する噴射ノズルを該排気系の配管の底壁部側にて先端部を鉛直上方又は斜め上方に向けて取り付けることにより、該噴射ノズルより還元剤を下方から上方に向けて噴射供給して該還元剤を排気中で拡散、混合させると共に、上記噴射ノズルに還元剤が析出するのを防止し、エンジンの排気浄化装置が有する機能の維持、適正化を図ることを目的とする。   In view of the above, the present invention addresses such problems, and an injection nozzle that injects a reducing agent into the exhaust system of the engine has a tip portion vertically upward or obliquely upward on the bottom wall side of the exhaust system piping. By attaching the reducing agent, the reducing agent is injected and supplied from the lower side to the upper side to diffuse and mix the reducing agent in the exhaust gas, and the reducing agent is prevented from being deposited on the injection nozzle. The purpose is to maintain and optimize the functions of the engine exhaust purification system.

上記目的を達成するために、本発明によるエンジンの排気浄化装置は、エンジンの排気系に配設され、排気中の窒素酸化物を還元剤により還元浄化する還元触媒と、上記排気系にて上記還元触媒の排気上流側に取り付けられ、排気中に上記還元剤を噴射供給する噴射ノズルと、を備えたエンジンの排気浄化装置において、上記噴射ノズルは、上記排気系の配管の底壁部側にて先端部を鉛直上方又は斜め上方に向けて取り付け、その先端部の噴孔より還元剤を下方から上方に向けて噴射させるようにしたものである。   In order to achieve the above object, an exhaust emission control device for an engine according to the present invention is disposed in an exhaust system of an engine, and reduces and purifies nitrogen oxides in exhaust gas with a reducing agent. An exhaust purification device for an engine having an injection nozzle attached to an exhaust upstream side of a reduction catalyst and supplying the reducing agent into the exhaust, wherein the injection nozzle is disposed on a bottom wall portion side of the exhaust system pipe. The tip is attached vertically upward or obliquely upward, and the reducing agent is jetted upward from below from the nozzle hole of the tip.

このような構成により、上記排気系の配管の底壁部側にて先端部を鉛直上方又は斜め上方に向けて取り付けられた噴射ノズルの噴孔から、上記配管内に還元剤が下方から上方に向けて噴射される。   With such a configuration, the reducing agent is introduced from the bottom to the top in the pipe from the injection hole of the injection nozzle attached at the bottom wall side of the pipe of the exhaust system with the tip portion vertically upward or obliquely upward. It is injected towards.

また、上記噴射ノズルは、上記排気系の配管の底壁部に設けられた取り付け穴に着脱可能とされている。これにより、上記噴射ノズルを、上記排気系の配管の底壁部の取り付け穴から取り外すことができる。   The spray nozzle is attachable to and detachable from a mounting hole provided in a bottom wall portion of the exhaust system pipe. Thereby, the said injection nozzle can be removed from the attachment hole of the bottom wall part of the piping of the said exhaust system.

さらに、上記取り付け穴は、排気流の流れ方向に所定の長さだけ延びて形成されており、上記噴射ノズルを上記配管に固定する固定手段は、上記取り付け穴に適合する形状とされ、該固定手段の排気上流側に上記噴射ノズルが配設されたものである。これにより、上記噴射ノズルの固定手段を上記配管から取り外すと、該配管には排気流の流れ方向に所定の長さだけ延びた取り付け穴が空いた状態となる。   Further, the mounting hole is formed to extend by a predetermined length in the flow direction of the exhaust flow, and the fixing means for fixing the injection nozzle to the pipe is shaped to fit the mounting hole, and the fixing The injection nozzle is arranged on the exhaust upstream side of the means. Thus, when the fixing means for the injection nozzle is removed from the pipe, the pipe is provided with a mounting hole extending by a predetermined length in the flow direction of the exhaust flow.

請求項１に記載のエンジンの排気浄化装置によれば、エンジンの排気系の配管の底壁部側にて先端部を鉛直上方又は斜め上方に向けて取り付けられた噴射ノズルの噴孔から、上記配管内にて還元剤が下方から上方に向けて噴射されるため、該還元剤が上記配管内の底壁に付着するまでの時間が長くなり、上記還元剤が排気中で十分に拡散され、還元剤の混合を促進することができる。これにより、触媒中において排気中のＮＯｘの還元反応が効率的に進行するようになる。また、エンジンの排気系内の排気中に適量の還元剤を噴射供給すればよいので、噴射ノズルの噴孔の周辺に還元剤が析出し難くなり、噴孔の目詰まりを防止することもできる。したがって、エンジンの排気浄化装置が有する所期の機能の維持、適正化を図ることができる。   According to the exhaust emission control device for an engine according to claim 1, from the injection hole of the injection nozzle attached with the tip portion directed vertically upward or obliquely upward on the bottom wall side of the piping of the exhaust system of the engine, Since the reducing agent is injected from below to above in the pipe, it takes a long time for the reducing agent to adhere to the bottom wall in the pipe, and the reducing agent is sufficiently diffused in the exhaust, Mixing of the reducing agent can be promoted. As a result, the reduction reaction of NOx in the exhaust proceeds efficiently in the catalyst. Also, since an appropriate amount of reducing agent may be injected and supplied into the exhaust gas in the exhaust system of the engine, it becomes difficult for the reducing agent to be deposited around the nozzle hole of the injection nozzle, and clogging of the nozzle hole can be prevented. . Therefore, it is possible to maintain and optimize the expected functions of the engine exhaust purification device.

また、請求項２に記載の発明によれば、上記噴射ノズルは、上記排気系の配管の底壁部に設けられた取り付け穴から取り外すことができるので、該取り付け穴から上記配管内に析出した析出物を除去することができる。また、上記噴射ノズルの噴孔が目詰まりした場合であっても、該噴射ノズルを取り外して、噴孔に目詰まりした還元剤を容易に除去することができる。   According to the invention described in claim 2, since the injection nozzle can be removed from the mounting hole provided in the bottom wall portion of the exhaust system pipe, it is deposited in the pipe from the mounting hole. Precipitates can be removed. Further, even when the injection hole of the injection nozzle is clogged, the reducing nozzle clogged in the injection hole can be easily removed by removing the injection nozzle.

そして、請求項３に記載の発明によれば、上記噴射ノズルの固定手段を上記配管から取り外すと、該配管には排気流の流れ方向に所定の長さだけ延びた取り付け穴が空いた状態となるので、該取り付け穴から上記配管内に析出した析出物を容易に除去することができる。また、上記固定手段に付着した析出物についても、容易に除去することができる。   According to the invention described in claim 3, when the fixing means for the injection nozzle is removed from the pipe, the pipe has a mounting hole extending a predetermined length in the flow direction of the exhaust flow. Therefore, the deposit deposited in the pipe from the mounting hole can be easily removed. Moreover, the deposits attached to the fixing means can be easily removed.

以下、本発明の実施形態を添付図面に基づいて詳細に説明する。図１は本発明によるエンジンの排気浄化装置の概念を示すシステム図である。このエンジンの排気浄化装置は、車両に搭載されたエンジン１から排出された排気中のＮＯｘを還元剤により還元除去して排気を浄化する装置であって、排気マニフォールド２と、排気管３と、還元触媒４と、噴射ノズル５とを備えて成る。   Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a system diagram showing the concept of an engine exhaust purification system according to the present invention. This engine exhaust purification device is a device that purifies exhaust by reducing and removing NOx in exhaust exhausted from an engine 1 mounted on a vehicle with a reducing agent, and includes an exhaust manifold 2, an exhaust pipe 3, The reduction catalyst 4 and the injection nozzle 5 are provided.

上記エンジン１の排気マニフォールド２には、排気管３が接続されている。また、この排気管３の途中にはマフラ６が設けられており、このマフラ６内に排気中のＮＯｘを還元浄化する還元触媒４が収容されている。上記排気管３には、例えば排気上流側から順に一酸化窒素（ＮＯ）の酸化触媒、ＮＯｘの還元触媒４、アンモニアスリップ用酸化触媒の３つの触媒が配設されている。これにより、エンジン１から排出された排気は、排気マニフォールド２及び排気管３を通って還元触媒４を経由するときに、該還元触媒４でＮＯｘを還元除去して大気中に排出される。なお、上記排気マニフォールド２と排気管３と還元触媒４とで、エンジン１の排気系を構成している。また、図示省略したが、上記還元触媒４の前後には、温度センサ等が配設されている。   An exhaust pipe 3 is connected to the exhaust manifold 2 of the engine 1. A muffler 6 is provided in the middle of the exhaust pipe 3, and a reduction catalyst 4 for reducing and purifying NOx in the exhaust is housed in the muffler 6. In the exhaust pipe 3, for example, three catalysts, an oxidation catalyst of nitric oxide (NO), a reduction catalyst 4 of NOx, and an oxidation catalyst for ammonia slip, are arranged in order from the exhaust upstream side. As a result, when the exhaust gas discharged from the engine 1 passes through the exhaust manifold 2 and the exhaust pipe 3 and passes through the reduction catalyst 4, NOx is reduced and removed by the reduction catalyst 4 and is discharged into the atmosphere. The exhaust manifold 2, the exhaust pipe 3, and the reduction catalyst 4 constitute an exhaust system of the engine 1. Although not shown, temperature sensors and the like are disposed before and after the reduction catalyst 4.

また、上記排気管３内にて還元触媒４の排気上流には、噴射ノズル５が取り付けられている。この噴射ノズル５は、後述する還元剤１２を霧状にして排気中に噴射供給するもので、該噴射ノズル５を固定する手段となるフランジ７を用いて上記排気管３に取り付けられている。さらに、図１に示すように、上記フランジ７に固定された噴射ノズル５には供給パイプ８が連結されており、この供給パイプ８の他端部には上記噴射ノズル５への還元剤１２の供給を制御する還元剤供給装置９が接続されている。さらにまた、上記還元剤供給装置９には供給配管１０が接続されており、その吸込口１０ａが貯蔵タンク１１の底面付近に位置している。そして、貯蔵タンク１１内には還元剤（例えば、尿素水）１２が蓄えられている。   An injection nozzle 5 is attached upstream of the reduction catalyst 4 in the exhaust pipe 3. The injection nozzle 5 is used to inject and supply a reducing agent 12 described later in the form of a mist into the exhaust gas, and is attached to the exhaust pipe 3 using a flange 7 that serves as a means for fixing the injection nozzle 5. Further, as shown in FIG. 1, a supply pipe 8 is connected to the injection nozzle 5 fixed to the flange 7, and the reducing agent 12 to the injection nozzle 5 is connected to the other end of the supply pipe 8. A reducing agent supply device 9 for controlling supply is connected. Furthermore, a supply pipe 10 is connected to the reducing agent supply device 9, and the suction port 10 a is located near the bottom surface of the storage tank 11. A reductant (for example, urea water) 12 is stored in the storage tank 11.

これにより、上記貯蔵タンク１１内に蓄えられた還元剤１２は、供給配管１０の吸込口１０ａから吸い込まれて還元剤供給装置９に補給される。そして、この還元剤供給装置９から供給パイプ８を介して噴射ノズル５に送られた還元剤１２は、排気管３内に圧力空気と共に噴射供給されるようになる。この噴射ノズル５から噴射供給された還元剤１２は、排気管３内を通る排気の排気熱により加水分解してアンモニアを容易に発生する。このように得られたアンモニアは、上記還元触媒４において排気中のＮＯｘと反応し、水及び無害なガスに浄化されることは知られたことである。なお、本実施形態では、還元剤１２として尿素水が用いられるが、本発明はこれに限られず、アンモニア水溶液等を用いてもよい。   Thereby, the reducing agent 12 stored in the storage tank 11 is sucked from the suction port 10 a of the supply pipe 10 and is supplied to the reducing agent supply device 9. Then, the reducing agent 12 sent from the reducing agent supply device 9 to the injection nozzle 5 through the supply pipe 8 is injected and supplied together with the pressure air into the exhaust pipe 3. The reducing agent 12 injected and supplied from the injection nozzle 5 is easily hydrolyzed by the exhaust heat of the exhaust gas passing through the exhaust pipe 3 to easily generate ammonia. It is known that the ammonia thus obtained reacts with NOx in the exhaust gas in the reduction catalyst 4 and is purified into water and harmless gas. In the present embodiment, urea water is used as the reducing agent 12, but the present invention is not limited to this, and an aqueous ammonia solution or the like may be used.

ここで、本発明においては、図２に示すように、上記噴射ノズル５は、上記排気管３の底壁部にて先端部を鉛直上方に向けて取り付けておき、その先端部の噴孔５ａより還元剤１２を下方から上方に向けて噴射させるようにされている。これにより、排気管３の底壁部に配設された噴射ノズル５の噴孔５ａから、上記排気管３内にて還元剤１２が下方から上方に向けて噴射されるため、該還元剤１２が上記排気管３内の底壁に付着するまでの時間が長くなって、エンジンの排気系に噴射供給された還元剤１２が排気中で十分に拡散され、還元剤１２の混合を促進することができる。したがって、図１に示す還元触媒４中において、排気ガス中のＮＯｘの還元反応が効率的に進行するようになる。その結果、ＮＯｘの浄化率が向上し、エンジンの排気浄化装置が有する所期の機能の維持、適正化を図ることが可能となる。なお、図２に示すように、上記噴射ノズル５から噴射された還元剤１２は、上記排気管３内の底壁の広い範囲Ａ2に付着するようになる。この還元剤１２が付着する範囲Ａ2は、図５に示す範囲Ａ1よりも広くなる。 Here, in the present invention, as shown in FIG. 2, the injection nozzle 5 is attached to the bottom wall portion of the exhaust pipe 3 with its tip portion directed vertically upward, and the nozzle hole 5 a at the tip portion thereof. Further, the reducing agent 12 is jetted upward from below. As a result, the reducing agent 12 is jetted upward from below into the exhaust pipe 3 from the injection hole 5a of the injection nozzle 5 disposed on the bottom wall portion of the exhaust pipe 3. Therefore, the reducing agent 12 It takes a long time to adhere to the bottom wall in the exhaust pipe 3, and the reducing agent 12 injected and supplied to the exhaust system of the engine is sufficiently diffused in the exhaust to promote the mixing of the reducing agent 12. Can do. Therefore, the reduction reaction of NOx in the exhaust gas proceeds efficiently in the reduction catalyst 4 shown in FIG. As a result, the NOx purification rate is improved, and it is possible to maintain and optimize the expected function of the engine exhaust gas purification device. As shown in FIG. 2, the reducing agent 12 injected from the injection nozzle 5 adheres to a wide range A 2 on the bottom wall in the exhaust pipe 3. The range A 2 to which the reducing agent 12 adheres is wider than the range A 1 shown in FIG.

また、上記噴射ノズル５が鉛直上方を向いているので、還元剤１２の噴射供給を停止したときに、該噴射ノズル５内に残留した還元剤１２が供給パイプ８側に垂れて戻されるようになるので、上記噴孔５ａの周辺に還元剤１２が析出し難くなり、該噴孔５ａの目詰まりを防止することもできる。これにより、上記噴射ノズル５から還元剤１２を再度噴射供給するときに、必要量以上の還元剤１２を噴射供給しなくてもよく、適量の還元剤１２を噴射供給すれば、所定のＮＯｘ浄化率を得ることができるので、還元剤１２が無駄に消費されることを抑制し、ランニングコストを低減することができる。したがって、噴射ノズル５から排気中に十分な量の還元剤１２が常に噴射供給されるようになるので、エンジンの排気浄化装置が有する所期の機能の維持、適正化を図ることが可能となる。   Further, since the injection nozzle 5 faces vertically upward, when the supply of the reducing agent 12 is stopped, the reducing agent 12 remaining in the injection nozzle 5 is drooped back to the supply pipe 8 side. As a result, the reducing agent 12 does not easily deposit around the nozzle hole 5a, and the nozzle hole 5a can be prevented from being clogged. As a result, when the reducing agent 12 is supplied again from the injection nozzle 5, it is not necessary to inject and supply more reducing agent 12 than the necessary amount. Since a rate can be obtained, it can suppress that the reducing agent 12 is consumed wastefully and can reduce a running cost. Accordingly, since a sufficient amount of the reducing agent 12 is always supplied by being injected from the injection nozzle 5 into the exhaust gas, it is possible to maintain and optimize the expected function of the exhaust purification device of the engine. .

また、上記噴射ノズル５は、上記排気管３の底壁部に設けられた取り付け穴３ａから着脱可能とされている。具体的には、上記フランジ７を排気管３に締結しているボルト１３を取り外すことにより、噴射ノズル５を排気管３の底壁部の取り付け穴３ａから取り外すことができる。したがって、上記噴射ノズル５の噴孔５ａが目詰まりした場合であっても、該噴孔５ａに目詰まりした還元剤１２を容易に除去することができる。   The injection nozzle 5 is detachable from an attachment hole 3 a provided in the bottom wall portion of the exhaust pipe 3. Specifically, the injection nozzle 5 can be removed from the mounting hole 3 a in the bottom wall portion of the exhaust pipe 3 by removing the bolt 13 that fastens the flange 7 to the exhaust pipe 3. Therefore, even if the injection hole 5a of the injection nozzle 5 is clogged, the reducing agent 12 clogged in the injection hole 5a can be easily removed.

図３は、本発明の第２の実施形態を示す要部拡大断面図である。この実施形態は、噴射ノズル５は、上記排気管３の底壁部側にて先端部を斜め上方に向けて取り付けておき、その先端部の噴孔５ａより還元剤１２を下方から上方に噴射させるようにしたものである。このとき、図３（ｂ）に示すように、噴射ノズル５の先端部の噴孔５ａは、上方を向いて形成されている。これにより、上記噴射ノズル５の噴孔５ａより、上記排気管３内にて還元剤１２が下方から上方に向けて噴射されるため、該還元剤１２が上記排気管３内の底壁に付着するまでの時間が長くなって、エンジンの排気系に噴射供給された還元剤１２が排気中で十分に拡散され、排気中での還元剤１２の混合を促進することができる。したがって、噴射ノズル５の噴孔５ａから排気中に十分な量の還元剤１２が常に噴射供給されるようになるので、エンジンの排気浄化装置が有する所期の機能の維持、適正化を図ることが可能となる。   FIG. 3 is an enlarged cross-sectional view of a main part showing a second embodiment of the present invention. In this embodiment, the injection nozzle 5 is attached to the bottom wall portion side of the exhaust pipe 3 with its tip portion inclined upward, and the reducing agent 12 is injected from below to above from the nozzle hole 5a. It is made to let you. At this time, as shown in FIG. 3B, the injection hole 5a at the tip of the injection nozzle 5 is formed facing upward. As a result, the reducing agent 12 is injected from the lower side to the upper side in the exhaust pipe 3 from the injection hole 5 a of the injection nozzle 5, so that the reducing agent 12 adheres to the bottom wall in the exhaust pipe 3. As a result, the reducing agent 12 injected and supplied to the exhaust system of the engine is sufficiently diffused in the exhaust, and the mixing of the reducing agent 12 in the exhaust can be promoted. Accordingly, since a sufficient amount of the reducing agent 12 is always injected and supplied from the nozzle hole 5a of the injection nozzle 5 into the exhaust gas, the intended function of the engine exhaust gas purification device should be maintained and optimized. Is possible.

図４は、本発明の第３の実施形態を示す要部拡大断面図である。この実施形態は、上記排気管３の取り付け穴３ａが排気流の流れ方向に所定の長さだけ延びて形成されており、上記噴射ノズル５の固定手段となるフランジ７’は、上記取り付け穴３ａに適合する形状とされ、該フランジ７’の排気上流側に噴射ノズル５が配設されたものである。ここで、上記取り付け穴３の長さは、上記噴射ノズル５から噴射された還元剤１２が上記排気管３の底壁に付着する範囲に相当する長さに形成されている。これにより、上記フランジ７’を排気管３から取り外すと、該排気管３には排気流の流れ方向に所定の長さだけ延びた取り付け穴３ａが空いた状態となるので、該取り付け穴３ａから排気管３内に析出した析出物を容易に除去することができる。また、上記噴射ノズル５から噴射されてフランジ７’に付着した析出物１４についても、容易に除去することができる。したがって、エンジンの排気浄化装置が有する所期の機能の維持、適正化を図ることが可能となる。   FIG. 4 is an enlarged cross-sectional view of a main part showing a third embodiment of the present invention. In this embodiment, the mounting hole 3a of the exhaust pipe 3 is formed by extending a predetermined length in the flow direction of the exhaust flow, and the flange 7 'serving as a fixing means for the injection nozzle 5 is formed by the mounting hole 3a. The injection nozzle 5 is disposed on the exhaust upstream side of the flange 7 ′. Here, the length of the mounting hole 3 is formed to correspond to a range in which the reducing agent 12 injected from the injection nozzle 5 adheres to the bottom wall of the exhaust pipe 3. As a result, when the flange 7 ′ is removed from the exhaust pipe 3, the exhaust pipe 3 is provided with a mounting hole 3a extending a predetermined length in the flow direction of the exhaust flow. Deposits deposited in the exhaust pipe 3 can be easily removed. Further, the precipitate 14 sprayed from the spray nozzle 5 and attached to the flange 7 'can be easily removed. Therefore, it is possible to maintain and optimize the expected function of the engine exhaust purification device.

本発明によるエンジンの排気浄化装置の概念を示すシステム図である。1 is a system diagram showing a concept of an engine exhaust gas purification apparatus according to the present invention. 図１に示す噴射ノズルの実施形態を示す要部拡大断面図である。It is a principal part expanded sectional view which shows embodiment of the injection nozzle shown in FIG. 本発明の第２の実施形態を示す要部拡大断面図であり、（ａ）の部分Ｐの拡大図を（ｂ）に示す。It is a principal part expanded sectional view which shows the 2nd Embodiment of this invention, and the enlarged view of the part P of (a) is shown in (b). 本発明の第３の実施形態を示す要部拡大断面図である。It is a principal part expanded sectional view which shows the 3rd Embodiment of this invention. 従来の還元剤の供給系を示す要部拡大断面図である。It is a principal part expanded sectional view which shows the supply system of the conventional reducing agent.

符号の説明Explanation of symbols

１…エンジン
２…排気マニフォールド
３…排気管
４…還元触媒
５…噴射ノズル
５ａ…噴孔
６…マフラ
７，７’…フランジ
８…供給パイプ
９…還元剤供給装置
１０…供給配管
１１…貯蔵タンク
１２…還元剤
１４…析出物 DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Exhaust manifold 3 ... Exhaust pipe 4 ... Reduction catalyst 5 ... Injection nozzle 5a ... Injection hole 6 ... Muffler 7, 7 '... Flange 8 ... Supply pipe 9 ... Reductant supply apparatus 10 ... Supply pipe 11 ... Storage tank 12 ... Reducing agent 14 ... Precipitate

Claims (3)

エンジンの排気系に配設され、排気中の窒素酸化物を還元剤により還元浄化する還元触媒と、
上記排気系にて上記還元触媒の排気上流側に取り付けられ、排気中に上記還元剤を噴射供給する噴射ノズルと、を備えたエンジンの排気浄化装置において、
上記噴射ノズルは、上記排気系の配管の底壁部側にて先端部を鉛直上方又は斜め上方に向けて取り付け、その先端部の噴孔より還元剤を下方から上方に向けて噴射させるようにしたことを特徴とするエンジンの排気浄化装置。 A reduction catalyst disposed in the exhaust system of the engine for reducing and purifying nitrogen oxides in the exhaust with a reducing agent;
In an exhaust purification device for an engine, comprising an injection nozzle attached to the exhaust upstream side of the reduction catalyst in the exhaust system and supplying the reducing agent into the exhaust.
The injection nozzle is attached so that the tip is vertically upward or obliquely upward on the bottom wall side of the exhaust system pipe, and the reducing agent is injected from below to above from the nozzle hole of the tip. An exhaust emission control device for an engine characterized by that. 上記噴射ノズルは、上記排気系の配管の底壁部に設けられた取り付け穴に着脱可能とされたことを特徴とする請求項１記載のエンジンの排気浄化装置。   2. The exhaust emission control device for an engine according to claim 1, wherein the injection nozzle is attachable to and detachable from a mounting hole provided in a bottom wall portion of the exhaust system pipe. 上記取り付け穴は、排気流の流れ方向に所定の長さだけ延びて形成されており、上記噴射ノズルを上記配管に固定する固定手段は、上記取り付け穴に適合する形状とされ、該固定手段の排気上流側に上記噴射ノズルが配設されたことを特徴とする請求項２記載のエンジンの排気浄化装置。   The mounting hole is formed to extend a predetermined length in the flow direction of the exhaust flow, and the fixing means for fixing the injection nozzle to the pipe is shaped to fit the mounting hole. The engine exhaust gas purification apparatus according to claim 2, wherein the injection nozzle is disposed upstream of the exhaust gas.
JP2004025754A 2004-02-02 2004-02-02 Engine exhaust purification system Expired - Fee Related JP4137807B2 (en)

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JP2004025754A JP4137807B2 (en) 2004-02-02 2004-02-02 Engine exhaust purification system
EP05709649A EP1712754A4 (en) 2004-02-02 2005-02-02 Device for purifying exhaust gas of internal combustion engine
PCT/JP2005/001529 WO2005073527A1 (en) 2004-02-02 2005-02-02 Device for purifying exhaust gas of internal combustion engine
US11/495,636 US8011176B2 (en) 2004-02-02 2006-07-31 Exhaust emission purifying apparatus for internal combustion engine
US12/954,343 US20110067385A1 (en) 2004-02-02 2010-11-24 Exhaust emission purifying apparatus for internal combustion engine
US12/954,337 US8578703B2 (en) 2004-02-02 2010-11-24 Exhaust emission purifying apparatus for internal combustion engine

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008082253A (en) * 2006-09-28 2008-04-10 Nissan Diesel Motor Co Ltd Structure for liquid reducer injection nozzle
US7882697B2 (en) 2006-07-27 2011-02-08 Denso Corporation Exhaust gas purification apparatus
JP2017015081A (en) * 2015-06-29 2017-01-19 ゼネラル・エレクトリック・カンパニイ Power generation system exhaust cooling

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7882697B2 (en) 2006-07-27 2011-02-08 Denso Corporation Exhaust gas purification apparatus
JP2008082253A (en) * 2006-09-28 2008-04-10 Nissan Diesel Motor Co Ltd Structure for liquid reducer injection nozzle
JP2017015081A (en) * 2015-06-29 2017-01-19 ゼネラル・エレクトリック・カンパニイ Power generation system exhaust cooling

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