JP2009097436A - Exhaust emission control device of internal combustion engine - Google Patents

Exhaust emission control device of internal combustion engine Download PDF

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Publication number
JP2009097436A
JP2009097436A JP2007270185A JP2007270185A JP2009097436A JP 2009097436 A JP2009097436 A JP 2009097436A JP 2007270185 A JP2007270185 A JP 2007270185A JP 2007270185 A JP2007270185 A JP 2007270185A JP 2009097436 A JP2009097436 A JP 2009097436A
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Prior art keywords
exhaust
reducing agent
internal combustion
combustion engine
exhaust pipe
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JP2007270185A
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Japanese (ja)
Inventor
Yasuko Suzuki
康子 鈴木
Hiroaki Fujita
博昭 藤田
Satoshi Hiranuma
智 平沼
Shinichi Saito
真一 斎藤
Masayuki Katabuchi
雅之 片渕
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Mitsubishi Fuso Truck and Bus Corp
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Mitsubishi Fuso Truck and Bus Corp
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Priority to JP2007270185A priority Critical patent/JP2009097436A/en
Priority to DE102008050555A priority patent/DE102008050555A1/en
Priority to US12/247,220 priority patent/US20090100827A1/en
Publication of JP2009097436A publication Critical patent/JP2009097436A/en
Withdrawn legal-status Critical Current

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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
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • 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
    • F01N13/009—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 having two or more separate purifying devices arranged in series
    • 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
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • 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
    • F01N2340/00—Dimensional characteristics of the exhaust system, e.g. length, diameter or volume of the apparatus; Spatial arrangements of exhaust apparatuses
    • 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
    • F01N2450/00—Methods or apparatus for fitting, inserting or repairing different elements
    • F01N2450/20—Methods or apparatus for fitting, inserting or repairing different elements by mechanical joints, e.g. by deforming housing, tube, baffle plate or parts thereof
    • 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
    • F01N2470/00—Structure or shape of gas passages, pipes or tubes
    • F01N2470/30—Tubes with restrictions, i.e. venturi or the like, e.g. for sucking air or measuring mass flow
    • 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
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device of an internal combustion engine capable of preventing the precipitation of a reducing agent in a joint of an exhaust pipe, and suppressing the deposition of the reducing agent in a throttle part. <P>SOLUTION: This exhaust emission control device of the internal combustion engine includes: a Venturi part of the exhaust pipe formed by joining two parts shaped to be cut in the axial direction with respect to each other; and a reducing agent supply part for injecting and supplying a urea water solution into the exhaust pipe, wherein the Venturi part is disposed so that the joint is located in the lateral direction from the center on a cross section. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、内燃機関の排気浄化装置に係り、詳しくは、排気管内に還元剤を噴射して排気浄化触媒に還元剤を供給する技術に関する。   The present invention relates to an exhaust purification device for an internal combustion engine, and more particularly to a technique for injecting a reducing agent into an exhaust pipe and supplying the reducing agent to an exhaust purification catalyst.

ディーゼルエンジンの排気を浄化する排気ガス後処理システムとして、ＳＣＲシステムが知られている。ＳＣＲシステムは、排気管に介装されたＳＣＲ触媒の上流側に噴射ノズルを備え、この噴射ノズルから還元剤を噴射供給することで、ＳＣＲ触媒において排気中の窒素酸化物を無害な窒素及び水に還元する。更に、還元剤の噴射位置近傍で排気管に絞り部を設けており、この絞り部により排気の流速を上昇させて還元剤を排気中に十分に拡散させ、ＳＣＲ触媒における排気浄化性能の向上を図っている（特許文献１）。
特開２００２−２１３２３３号公報 An SCR system is known as an exhaust gas aftertreatment system for purifying exhaust gas from a diesel engine. The SCR system includes an injection nozzle on the upstream side of the SCR catalyst interposed in the exhaust pipe. By supplying a reducing agent from the injection nozzle, nitrogen oxides in the exhaust gas in the SCR catalyst are harmless with nitrogen and water. To reduce. In addition, a throttle is provided in the exhaust pipe near the injection position of the reducing agent, and this throttle increases the flow rate of the exhaust to sufficiently diffuse the reducing agent into the exhaust, thereby improving the exhaust purification performance of the SCR catalyst. (Patent Document 1).
JP 2002-213233 A

上記ＳＣＲシステムの還元剤としては安全性及び取扱性を考慮して尿素水溶液が広く用いられている。
また、上記排気管の絞り部は、一般的には、軸線方向に分割した２つの型によって夫々プレス成形した部品を溶接等により接合することで得られる。
しかしながら、このような接合形状の排気管では、噴射ノズルから尿素水溶液を噴射すると、下方に位置する排気管の合わせ目に尿素水溶液が溜まり、そこで尿素水溶液から尿素が析出して堆積する虞がある。このように、合わせ目に尿素が堆積すると、そこが基点となって尿素が絞り部で堆積し易くなってしまう。また、合わせ目に尿素が堆積すると、この合わせ目から排気管が腐食する虞がある。更には、噴射ノズルから噴射した尿素水溶液の成分である尿素が絞り部で析出してしまうと、排気中に拡散される尿素水溶液が減少し、ＳＣＲ触媒における排気浄化性能が低下してしまうといった問題点がある。 As the reducing agent for the SCR system, an aqueous urea solution is widely used in consideration of safety and handleability.
Further, the throttle part of the exhaust pipe is generally obtained by joining parts press-formed by two molds divided in the axial direction by welding or the like.
However, in the exhaust pipe having such a joint shape, when the aqueous urea solution is injected from the injection nozzle, the aqueous urea solution accumulates at the joint of the exhaust pipe located below, and there is a risk that urea precipitates and accumulates from the aqueous urea solution there. . In this way, when urea is deposited at the joint, urea becomes easy to deposit at the throttle portion as a base point. Further, when urea accumulates at the joint, the exhaust pipe may corrode from the joint. Furthermore, if urea, which is a component of the urea aqueous solution injected from the injection nozzle, precipitates at the throttle portion, the urea aqueous solution diffused into the exhaust gas decreases, and the exhaust purification performance of the SCR catalyst decreases. There is a point.

本発明はこのような問題点を解決するためになされたもので、その目的とするところは、排気管の合わせ目における還元剤の析出を防止し、絞り部での還元剤の堆積を抑制する内燃機関の排気浄化装置を提供することにある。   The present invention has been made to solve such problems, and the object of the present invention is to prevent the deposition of the reducing agent at the joint of the exhaust pipe and suppress the deposition of the reducing agent at the throttle portion. An object of the present invention is to provide an exhaust emission control device for an internal combustion engine.

上記の目的を達成するために、請求項１の発明では、内燃機関の排気管に設けられた排気浄化触媒と、前記排気浄化触媒の上流側に設けられ、前記排気管を絞るように形成された絞り部と、前記絞り部またはその上流側に近接した位置で前記排気管内に還元剤を噴射する還元剤噴射装置と、を備えた内燃機関の排気浄化装置において、前記絞り部は、軸線方向に切断した２個の部品を合わせて接合することで形成され、その合わせ目が断面上で中心から左右方向に位置するように配置されることを特徴とする。   In order to achieve the above object, according to the first aspect of the present invention, an exhaust purification catalyst provided in an exhaust pipe of an internal combustion engine and an upstream side of the exhaust purification catalyst are formed so as to restrict the exhaust pipe. In the exhaust gas purification apparatus for an internal combustion engine, the throttle unit is arranged in the axial direction, and a reducing agent injection device that injects a reducing agent into the exhaust pipe at a position close to the throttle unit or its upstream side. It is characterized by being formed by joining two parts cut together and being arranged so that the joint is located in the left-right direction from the center on the cross section.

また、請求項２の発明では、請求項１において、前記絞り部は、前記合わせ目が断面上で中心を通る水平線に対して上下角度が夫々２２．５度の範囲内に位置するように配置されることを特徴とする。   According to a second aspect of the present invention, in the first aspect of the present invention, in the first aspect, the throttle portion is disposed such that the vertical angle is within a range of 22.5 degrees with respect to a horizontal line passing through the center on the cross section. It is characterized by being.

本発明の請求項１の内燃機関の排気浄化装置によれば、絞り部の合わせ目が下方に位置しないので、還元剤噴射ノズルから還元剤が噴射されても合わせ目に還元剤が溜まることがない。したがって、合わせ目において還元剤が析出することがなく、合わせ目を基点とする還元剤の堆積が防止され、絞り部での還元剤の堆積を抑制することができる。
また、本発明の請求項２の内燃機関の排気浄化装置によれば、合わせ目での還元剤の析出を確実に防止することができる。 According to the exhaust gas purification apparatus for an internal combustion engine of claim 1 of the present invention, since the joint of the throttle portion is not located below, even if the reducing agent is injected from the reducing agent injection nozzle, the reducing agent can accumulate in the joint. Absent. Therefore, the reducing agent does not deposit at the joint, and the accumulation of the reducing agent based on the joint is prevented, and the accumulation of the reducing agent at the throttle portion can be suppressed.
According to the exhaust gas purification apparatus for an internal combustion engine of claim 2 of the present invention, it is possible to reliably prevent the reducing agent from being deposited at the joint.

以下、図面に基づき本発明の実施形態について説明する。
図１は、本発明の排気浄化装置が適用されたディーゼルエンジン（以下、単にエンジン１という）の排気系の概略構成図である。
エンジン１は、走行駆動源として車両に搭載されている。
図１に示すように、エンジン１の排気系には、排気中の窒素酸化物を還元除去するＳＣＲシステム２が採用されている。ＳＣＲシステム２は、エンジン１の排気管３に介装されたＳＣＲ触媒４と、排気中に還元剤として尿素水溶液を供給する還元剤供給装置５とを含んで構成されている。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an exhaust system of a diesel engine (hereinafter simply referred to as an engine 1) to which an exhaust purification apparatus of the present invention is applied.
The engine 1 is mounted on a vehicle as a travel drive source.
As shown in FIG. 1, an SCR system 2 that reduces and removes nitrogen oxides in the exhaust is employed in the exhaust system of the engine 1. The SCR system 2 includes an SCR catalyst 4 interposed in an exhaust pipe 3 of the engine 1 and a reducing agent supply device 5 that supplies an aqueous urea solution as a reducing agent into the exhaust gas.

還元剤供給装置５は、尿素水溶液を貯蔵するタンク６と、ＳＣＲ触媒４の上流で排気管３内に先端が開口した噴射ノズル７と、タンク６内の尿素水溶液を噴射ノズル７に供給するポンプ８とを備えており、エンジン１の運転状況等に応じてポンプ８が作動制御されることで、タンク６内の尿素水溶液を噴射ノズル７から排気管３内に噴射供給する機能を有する。   The reducing agent supply device 5 includes a tank 6 for storing a urea aqueous solution, an injection nozzle 7 having a tip opened in the exhaust pipe 3 upstream of the SCR catalyst 4, and a pump for supplying the urea aqueous solution in the tank 6 to the injection nozzle 7. 8 and has a function of injecting and supplying urea aqueous solution in the tank 6 from the injection nozzle 7 into the exhaust pipe 3 by controlling the operation of the pump 8 in accordance with the operating state of the engine 1 and the like.

還元剤供給装置５により噴射ノズル７から排気管３内に噴射供給された尿素水溶液は、排気の熱と水分とにより加水分解して、アンモニアが発生する。そして、このアンモニアは排気とともにＳＣＲ触媒４に流入し、ＳＣＲ触媒４にて排気中の窒素酸化物を還元反応させ、無害な窒素と水とに分解する。
ＳＣＲ触媒４の上流側には、排気中のＰＭ（排気微粒子）等を捕捉するフィルタ９が設けられており、ＳＣＲ触媒４へのＰＭの流入を防止している。フィルタ９とＳＣＲ触媒４との間の排気管３には、ベンチュリ部（絞り部）１０が設けられている。ベンチュリ部１０は、排気管３内の流路を絞り、排気の流速を高める機能を有している。ベンチュリ部１０には、前述の還元剤供給装置５の噴射ノズル７が、その噴射口がベンチュリ部１０の断面略中心に位置するように配置されている。ベンチュリ部１０によって流速が高められた排気に尿素水溶液が噴射される構成になっている。このように流速が上昇した排気に尿素水溶液が噴射することで、排気中に尿素水溶液が十分に拡散され、加水分解並びにＳＣＲ触媒４での還元反応の効率が向上する。 The urea aqueous solution injected and supplied from the injection nozzle 7 into the exhaust pipe 3 by the reducing agent supply device 5 is hydrolyzed by the heat and moisture of the exhaust to generate ammonia. This ammonia flows into the SCR catalyst 4 together with the exhaust gas, and the SCR catalyst 4 causes nitrogen oxides in the exhaust gas to undergo a reduction reaction and decomposes into harmless nitrogen and water.
A filter 9 that captures PM (exhaust particulates) and the like in the exhaust is provided on the upstream side of the SCR catalyst 4 to prevent the PM from flowing into the SCR catalyst 4. The exhaust pipe 3 between the filter 9 and the SCR catalyst 4 is provided with a venturi portion (throttle portion) 10. The venturi unit 10 has a function of restricting the flow path in the exhaust pipe 3 and increasing the flow rate of exhaust gas. In the venturi unit 10, the injection nozzle 7 of the above-described reducing agent supply device 5 is disposed so that the injection port is positioned at the approximate center of the cross section of the venturi unit 10. The urea aqueous solution is injected into the exhaust gas whose flow velocity is increased by the venturi unit 10. By injecting the urea aqueous solution into the exhaust gas whose flow rate has increased in this way, the urea aqueous solution is sufficiently diffused into the exhaust gas, and the efficiency of hydrolysis and reduction reaction at the SCR catalyst 4 is improved.

更に、噴射ノズル７の直上流側には、混合拡散デバイス１１が設けられている。混合拡散デバイス１１は、例えば排気に旋回流を発生させる機能を有しており、ベンチュリ部１０における尿素水溶液の拡散効果を更に向上させる。
図２はベンチュリ部１０の詳細構造を示し、（Ａ）は側面図、（Ｂ）は断面図である。
図２（Ａ）に示すように、ベンチュリ部１０は、筒状部材の中央部を絞って鼓状に形成されている。このような形状のベンチュリ部１０は、軸線に沿って上半分側の上部部材１０ａと下半分側の下部部材１０ｂとを合わせて溶接等により接合して形成されている。上部部材１０ａ及び下部部材１０ｂは夫々プレスによって製造されており、その内壁は滑らかに形成されている。そして、図２（Ｂ）に示すように、ベンチュリ部１０は、上部部材１０ａと下部部材１０ｂとの合わせ目１０ｃが断面上で中心Ｃから左右方向に位置するように、車両に配置されている。 Furthermore, a mixing and diffusing device 11 is provided immediately upstream of the injection nozzle 7. The mixing / diffusion device 11 has a function of generating a swirling flow in the exhaust gas, for example, and further improves the diffusion effect of the urea aqueous solution in the venturi unit 10.
2A and 2B show a detailed structure of the venturi section 10, in which FIG. 2A is a side view and FIG. 2B is a cross-sectional view.
As shown in FIG. 2A, the venturi portion 10 is formed in a drum shape by narrowing the central portion of the cylindrical member. The venturi portion 10 having such a shape is formed by joining the upper member 10a on the upper half side and the lower member 10b on the lower half side along the axis by welding or the like. The upper member 10a and the lower member 10b are each manufactured by pressing, and the inner walls thereof are formed smoothly. As shown in FIG. 2B, the venturi portion 10 is arranged in the vehicle so that the joint 10c of the upper member 10a and the lower member 10b is located in the left-right direction from the center C on the cross section. .

以上のように構成することで、本発明の排気浄化装置では、噴射ノズル７から噴射した尿素水溶液がベンチュリ部１０の内壁に付着しても、この内壁の下部には合わせ目１０ｃがないので、合わせ目１０ｃに尿素水溶液が貯まることがない。したがって、合わせ目１０ｃでの尿素水溶液からの尿素の析出が防止され、ベンチュリ部１０での尿素の堆積を抑制することができる。このようにして、合わせ目１０ｃでの尿素の堆積が防止されることで、合わせ目１０ｃにおける腐食が防止される。また、ベンチュリ部１０での尿素の堆積が抑制されることで、噴射ノズル７から噴射された尿素水溶液が無駄なく排気中に拡散され、ＳＣＲ触媒４における排気浄化性能を十分に確保することができる。   By configuring as described above, in the exhaust purification device of the present invention, even if the urea aqueous solution injected from the injection nozzle 7 adheres to the inner wall of the venturi portion 10, there is no seam 10c at the lower portion of the inner wall. The urea aqueous solution does not accumulate in the joint 10c. Therefore, precipitation of urea from the urea aqueous solution at the joint 10c is prevented, and urea deposition at the venturi portion 10 can be suppressed. Thus, corrosion of the seam 10c is prevented by preventing urea from being deposited at the seam 10c. In addition, since urea deposition in the venturi unit 10 is suppressed, the urea aqueous solution injected from the injection nozzle 7 is diffused into the exhaust gas without waste, and the exhaust purification performance of the SCR catalyst 4 can be sufficiently ensured. .

図３は、ベンチュリ部１０での尿素の堆積状況の一例を示す説明図である。
図３は、低速運転を長期間実施したときの、ベンチュリ部１０での尿素の堆積状況を示す。
アイドリング等の低速運転を長期間繰り返されると、ベンチュリ部１０の底部１０ｄで尿素水溶液から尿素が析出して堆積する場合がある。しかしながら、このように堆積したとしても、尿素はベンチュリ部１０の下部に堆積するのであって、図３に示すように、尿素水溶液の噴射位置であるベンチュリ部１０の中心Ｃを通る水平線Ｌｈに対して下方２２．５度の範囲より上方には尿素が堆積しないことが実験により判明した。したがって、ベンチュリ部１０の合わせ目１０ｃが中心Ｃを通る水平線Ｌｈに対して上下角度が夫々２２．５度の範囲に位置するようにベンチュリ部１０を配置すれば、合わせ目１０ｃに尿素が堆積することが確実に防止される。 FIG. 3 is an explanatory diagram showing an example of the state of urea deposition in the venturi unit 10.
FIG. 3 shows the state of urea deposition in the venturi unit 10 when the low-speed operation is performed for a long period of time.
When low-speed operation such as idling is repeated for a long period of time, urea may precipitate from the urea aqueous solution and deposit on the bottom 10d of the venturi 10. However, even if it accumulates in this way, urea accumulates in the lower part of the venturi part 10, and as shown in FIG. 3, with respect to a horizontal line Lh passing through the center C of the venturi part 10 that is the injection position of the urea aqueous solution. Experiments have revealed that urea does not accumulate above the range of 22.5 degrees below. Therefore, if the venturi portion 10 is arranged so that the joint angle 10c of the venturi portion 10 is in the range of 22.5 degrees with respect to the horizontal line Lh passing through the center C, urea accumulates on the joint 10c. Is reliably prevented.

本発明に係る内燃機関の排気系の概略構成図である。1 is a schematic configuration diagram of an exhaust system of an internal combustion engine according to the present invention. ベンチュリ部の構造を示し、（Ａ）は側面図、（Ｂ）は断面図である。The structure of a venturi part is shown, (A) is a side view, (B) is sectional drawing. ベンチュリ部での尿素の堆積状況の一例を示す説明図である。It is explanatory drawing which shows an example of the deposition condition of the urea in a venturi part.

符号の説明Explanation of symbols

１ エンジン
２ ＳＣＲシステム
３ 排気管
４ ＳＣＲ触媒
５ 還元剤供給装置
７ 噴射ノズル
１０ ベンチュリ部
１０ｃ 合わせ目 1 Engine 2 SCR System 3 Exhaust Pipe 4 SCR Catalyst 5 Reducing Agent Supply Device 7 Injection Nozzle 10 Venturi 10c Joint

Claims (2)

内燃機関の排気管に設けられた排気浄化触媒と、
前記排気浄化触媒の上流側に設けられ、前記排気管を絞るように形成された絞り部と、
前記絞り部またはその上流側に近接した位置で前記排気管内に還元剤を噴射する還元剤噴射装置と、を備えた内燃機関の排気浄化装置において、
前記絞り部は、軸線方向に切断した２個の部品を合わせて接合することで形成され、その合わせ目が断面上で中心から左右方向に位置するように配置されることを特徴とする内燃機関の排気浄化装置。 An exhaust purification catalyst provided in an exhaust pipe of an internal combustion engine;
A throttle portion provided on the upstream side of the exhaust purification catalyst and formed to throttle the exhaust pipe;
An exhaust gas purification apparatus for an internal combustion engine comprising: a reducing agent injection device that injects a reducing agent into the exhaust pipe at a position close to the throttle portion or an upstream side thereof,
The throttle part is formed by joining two parts cut in the axial direction and joining them, and the joint is arranged so as to be located in the left-right direction from the center on the cross section. Exhaust purification equipment. 前記絞り部は、前記合わせ目が断面上で中心を通る水平線に対して上下角度が夫々２２．５度の範囲内に位置するように配置されることを特徴とする請求項１に記載の内燃機関の排気浄化装置。   2. The internal combustion engine according to claim 1, wherein the throttle portion is disposed so that the vertical angle is within a range of 22.5 degrees with respect to a horizontal line passing through the center on the cross section. Engine exhaust purification system.
JP2007270185A 2007-10-17 2007-10-17 Exhaust emission control device of internal combustion engine Withdrawn JP2009097436A (en)

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JP2007270185A JP2009097436A (en) 2007-10-17 2007-10-17 Exhaust emission control device of internal combustion engine
DE102008050555A DE102008050555A1 (en) 2007-10-17 2008-10-06 Exhaust gas purification device for an internal combustion engine
US12/247,220 US20090100827A1 (en) 2007-10-17 2008-10-07 Exhaust gas purification apparatus for internal combustion engine

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CN102155276A (en) * 2011-01-26 2011-08-17 烟台华龙商用机器有限公司 Tail gas emission purification system of diesel engine
CN103161547B (en) * 2012-05-24 2014-12-10 苏州派格丽减排系统有限公司 Selective catalytic reduction (SCR) self-suction metering injection system
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JP4445137B2 (en) 2001-01-12 2010-04-07 株式会社小松製作所 Engine exhaust purification structure
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US9650938B2 (en) 2010-03-19 2017-05-16 Hino Motors, Ltd. Exhaust emission control device
JP2013122218A (en) * 2011-12-12 2013-06-20 Mitsubishi Fuso Truck & Bus Corp Exhaust emission control device for internal combustion engine and method of detecting deposition of urea

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