JP2019011684A - Exhaust emission control system - Google Patents

Exhaust emission control system Download PDF

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JP2019011684A
JP2019011684A JP2017127243A JP2017127243A JP2019011684A JP 2019011684 A JP2019011684 A JP 2019011684A JP 2017127243 A JP2017127243 A JP 2017127243A JP 2017127243 A JP2017127243 A JP 2017127243A JP 2019011684 A JP2019011684 A JP 2019011684A
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Prior art keywords
exhaust
exhaust gas
exhaust pipe
pipe
urea water
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遊大 景山
Yudai Kageyama
遊大 景山
悠貴 上田
Yuki Ueda
悠貴 上田
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Isuzu Motors Ltd
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Isuzu Motors Ltd
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Priority to JP2017127243A priority Critical patent/JP2019011684A/en
Priority to PCT/JP2018/022398 priority patent/WO2019003895A1/en
Priority to CN201880039824.6A priority patent/CN110770420A/en
Publication of JP2019011684A publication Critical patent/JP2019011684A/en
Priority to PH12019502795A priority patent/PH12019502795A1/en
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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
    • 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
    • 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
    • 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

To provide an exhaust emission control system capable of performing desired exhaust emission control processing while preventing the accumulation of white product materials.SOLUTION: The exhaust emission control system includes an exhaust pipe constituting an exhaust passage of an internal combustion engine, and including a selective reduction type catalyst device and a reductant injector for injecting reductant. On the upstream side of the selective reduction type catalyst device out of the exhaust pipe in the flowing direction of exhaust gas passing through the exhaust pipe, a bent part is formed where the reductant injector is provided. On the upstream side of the bent part out of the exhaust pipe in the flowing direction, an inner pipe is arranged having an inner diameter smaller than the inner diameter of the exhaust pipe. Between the exhaust pipe and the inner pipe, there is a clearance where the exhaust gas passes.SELECTED DRAWING: Figure 1

Description

本発明は、排気ガス浄化システムに関する。   The present invention relates to an exhaust gas purification system.

トラックやバス等の車両に搭載されるディーゼルエンジンの排気ガス中のＮＯｘを浄化するための排気ガス浄化システムとして、尿素水等を還元剤として用いてＮＯｘを窒素と水に還元する選択触媒還元（ＳＣＲ：Selective Catalytic Reduction）システムが開発されている（例えば、特許文献１を参照）。   As an exhaust gas purification system for purifying NOx in exhaust gas of diesel engines mounted on vehicles such as trucks and buses, selective catalytic reduction (reducing NOx to nitrogen and water using urea water as a reducing agent) An SCR (Selective Catalytic Reduction) system has been developed (see, for example, Patent Document 1).

選択触媒還元システムは、尿素水タンクに貯留された尿素水を選択還元型触媒装置（ＳＣＲ装置）上流の排気管に供給し、排気ガスの熱で尿素を加水分解してアンモニアを生成し、このアンモニアによって選択還元型触媒装置内の触媒でＮＯｘを還元するものである。尿素水は、例えば排気通路を構成する排気管に設けられた尿素水インジェクタによって適量が噴射される。   The selective catalyst reduction system supplies urea water stored in a urea water tank to an exhaust pipe upstream of the selective reduction catalyst device (SCR device), and hydrolyzes urea with the heat of exhaust gas to generate ammonia. NOx is reduced by ammonia in the selective reduction catalyst device with ammonia. An appropriate amount of urea water is injected by, for example, a urea water injector provided in an exhaust pipe constituting the exhaust passage.

特開２０００−３０３８２６号公報JP 2000-303826 A

しかしながら、内燃機関の低負荷運転時など排気ガスの温度が低い場合、尿素水の噴射量が異常に多い場合、排気ガスの流量が少ないのに尿素水の噴射が連続した場合などには、尿素水の加水分解が不十分となり、排気管内、特に尿素水インジェクタの噴口部周辺に、尿素水が加水分解する際に生じる尿素結晶、シアヌル酸などに代表される白色生成物が堆積する。排気管内に白色生成物が堆積すると、例えば排気管内が閉塞し、所望の排気ガス浄化処理が実施できないおそれがあるという問題があった。   However, when the temperature of the exhaust gas is low, such as during low-load operation of the internal combustion engine, the urea water injection amount is abnormally large, or the urea water injection continues even though the exhaust gas flow rate is low, the urea water Hydrolysis of water becomes insufficient, and white products such as urea crystals and cyanuric acid generated when urea water is hydrolyzed accumulate in the exhaust pipe, particularly around the injection port of the urea water injector. If the white product is accumulated in the exhaust pipe, for example, the exhaust pipe is blocked, and there is a problem that a desired exhaust gas purification process may not be performed.

本発明の目的は、白色生成物の堆積を防止して所望の排気ガス浄化処理を実施することが可能な排気ガス浄化システムを提供することである。   An object of the present invention is to provide an exhaust gas purification system capable of performing a desired exhaust gas purification process while preventing the deposition of a white product.

本発明に係る排気ガス浄化システムは、
内燃機関の排気通路を構成する排気管に、選択還元型触媒装置と、還元剤を噴射する還元剤インジェクタとを備えて構成される排気ガス浄化システムであって、
前記排気管を通過する排気ガスの流れ方向において前記排気管のうち前記選択還元型触媒装置の上流側には、前記還元剤インジェクタが設けられた屈曲部が形成され、
前記流れ方向において前記排気管のうち前記屈曲部の上流側には、当該排気管の内径よりも小さい内径を有する内管が配置されており、当該排気管と当該内管との間に前記排気ガスが通過する隙間を有する。 An exhaust gas purification system according to the present invention includes:
An exhaust gas purification system comprising a selective reduction catalyst device and a reducing agent injector for injecting a reducing agent in an exhaust pipe constituting an exhaust passage of an internal combustion engine,
A bent portion provided with the reducing agent injector is formed on the upstream side of the selective reduction catalyst device in the exhaust pipe in the flow direction of the exhaust gas passing through the exhaust pipe,
An inner pipe having an inner diameter smaller than the inner diameter of the exhaust pipe is disposed on the upstream side of the bent portion of the exhaust pipe in the flow direction, and the exhaust pipe is disposed between the exhaust pipe and the inner pipe. There is a gap through which gas passes.

本発明によれば、白色生成物の堆積を防止して所望の排気ガス浄化処理を実施することができる。   According to the present invention, it is possible to perform the desired exhaust gas purification treatment while preventing the deposition of the white product.

本実施の形態における車両の構成を示す図である。It is a figure which shows the structure of the vehicle in this Embodiment. 本実施の形態における尿素水インジェクタの噴口部周辺の部分拡大図である。It is the elements on larger scale around the nozzle part of the urea water injector in this Embodiment.

以下、本発明の実施形態について図面を参照して説明する。図１は、本実施の形態における車両１の構成を示す図である。図１に示すように、トラックやバス等の車両１には、内燃機関１０と、排気系２０とが搭載されている。排気系２０は、本発明の排気ガス浄化システムとして機能する。   Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a vehicle 1 in the present embodiment. As shown in FIG. 1, a vehicle 1 such as a truck or a bus is equipped with an internal combustion engine 10 and an exhaust system 20. The exhaust system 20 functions as the exhaust gas purification system of the present invention.

まず、内燃機関１０の構成について説明する。内燃機関１０は、例えばディーゼルエンジンである。内燃機関１０の燃焼室１１において、燃料噴射インジェクタ１３は、燃焼室１１内に燃料を噴射する。なお、燃料噴射インジェクタ１３は、燃焼室１１の吸気ポートに燃料を噴射しても良い。燃料の噴射は、例えばＥＣＭ（図示せず）により制御される。また、燃焼室１１内の燃料は、ピストン１９の動作により圧縮されて燃焼する。   First, the configuration of the internal combustion engine 10 will be described. The internal combustion engine 10 is a diesel engine, for example. In the combustion chamber 11 of the internal combustion engine 10, the fuel injection injector 13 injects fuel into the combustion chamber 11. The fuel injection injector 13 may inject fuel into the intake port of the combustion chamber 11. The fuel injection is controlled by, for example, an ECM (not shown). The fuel in the combustion chamber 11 is compressed and burned by the operation of the piston 19.

吸気バルブ１５および排気バルブ１７は、開閉可能に構成される。吸気バルブ１５が開くことで、吸気用配管５０からの新気が燃焼室１１に吸入される。また、排気バルブ１７が開くことで、燃焼室１１で燃料が燃焼して生じた排気ガスが排気系２０（具体的には、排気管２１）に送り出される。   The intake valve 15 and the exhaust valve 17 are configured to be openable and closable. When the intake valve 15 is opened, fresh air from the intake pipe 50 is drawn into the combustion chamber 11. Further, when the exhaust valve 17 is opened, the exhaust gas generated by the combustion of fuel in the combustion chamber 11 is sent out to the exhaust system 20 (specifically, the exhaust pipe 21).

次に、排気系２０の構成について説明する。排気系２０は、内燃機関１０の排気通路を構成する排気管２１を有する。排気管２１は、主に金属製であり、例えば車両１の下部に設けられる。この排気管２１は、内燃機関１０において燃料の燃焼により生じた排気ガスを大気中（車外）に導く。   Next, the configuration of the exhaust system 20 will be described. The exhaust system 20 has an exhaust pipe 21 that constitutes an exhaust passage of the internal combustion engine 10. The exhaust pipe 21 is mainly made of metal, and is provided, for example, at the lower portion of the vehicle 1. The exhaust pipe 21 guides exhaust gas generated by fuel combustion in the internal combustion engine 10 to the atmosphere (outside the vehicle).

また、排気管２１の途中には、排気ガスを浄化（無害化）するために、様々な後処理装置が設けられている。本実施の形態では、後処理装置として、ＤＯＣ（酸化触媒）２３Ａと、ＤＰＦ２３Ｂと、ＳＣＲ２３Ｃ（本発明の選択還元型触媒装置に対応）と、ＲＤＯＣ２３Ｄとが設けられている。   Further, various post-processing devices are provided in the middle of the exhaust pipe 21 in order to purify (detoxify) the exhaust gas. In the present embodiment, DOC (oxidation catalyst) 23A, DPF 23B, SCR 23C (corresponding to the selective reduction catalyst device of the present invention), and RDOC 23D are provided as post-processing devices.

ＤＯＣ２３Ａは、金属製の担持体に、ロジウム、酸化セリウム、白金、酸化アルミニウム等を担持して形成される。ＤＯＣ２３Ａは、排気ガスに含まれる炭化水素（ＨＣ）および一酸化炭素（ＣＯ）を分解除去する。また、ＤＯＣ２３Ａは、排気２ガスに含まれるＮＯｘの大半を占める一酸化窒素（ＮＯ）を酸化して二酸化窒素（ＮＯ２）を生成する機能も有している。この機能を利用することで、ＤＰＦ２３Ｂに捕集されたＰＭの燃焼（ＰＭ再生）を促進することや、ＳＣＲ２３ＣのＮＯｘ浄化効率を向上することが可能になる。 The DOC 23A is formed by supporting rhodium, cerium oxide, platinum, aluminum oxide or the like on a metal carrier. The DOC 23A decomposes and removes hydrocarbons (HC) and carbon monoxide (CO) contained in the exhaust gas. The DOC 23A also has a function of generating nitrogen dioxide (NO 2 ) by oxidizing nitric oxide (NO) that occupies most of NOx contained in the exhaust 2 gas. By utilizing this function, it becomes possible to promote combustion (PM regeneration) of PM collected by the DPF 23B and to improve the NOx purification efficiency of the SCR 23C.

ＤＰＦ２３Ｂは、多孔質セラミック製のハニカムのチャンネル（セル）の入口と出口を交互に目封じしたモノリスハニカム型のウオールフローフィルタから形成される。ＤＰＦ２３Ｂは、排気ガスに含まれる粒子状物質（ＰＭ）を捕集除去する。   The DPF 23B is formed of a monolith honeycomb type wall flow filter in which the inlets and outlets of the channels (cells) of the honeycomb made of porous ceramic are alternately plugged. The DPF 23B collects and removes particulate matter (PM) contained in the exhaust gas.

排気管２１において、ＤＰＦ２３Ｂよりも下流側（具体的には、排気ガスの流れ方向における下流側）であって、ＳＣＲ２３Ｃよりも上流側には、尿素水を噴射するための尿素水インジェクタ２５（ドージングバルブとも言う）が設けられた屈曲部２１ａが形成されている。屈曲部２１ａの断面形状は、Ｓ字形状またはクランク形状である。   In the exhaust pipe 21, a urea water injector 25 (dosing) for injecting urea water is downstream of the DPF 23B (specifically, downstream of the exhaust gas flow direction) and upstream of the SCR 23C. A bent portion 21a provided with a valve is also formed. The cross-sectional shape of the bent portion 21a is S-shaped or crank-shaped.

排気管２１において例えばＳＣＲ２３Ｃの入口近傍には、排気ガスの温度を検出する温度センサ（図示せず）が設けられている。この温度センサは、尿素水の噴射の制御等に用いられる。   In the exhaust pipe 21, for example, a temperature sensor (not shown) for detecting the temperature of the exhaust gas is provided in the vicinity of the inlet of the SCR 23C. This temperature sensor is used for controlling the injection of urea water.

ＳＣＲ２３Ｃは、例えば円柱形状を有し、セラミックで作製されたハニカム担体を有する。ハニカム壁面には、例えばゼオライトやバナジウム等の触媒が担持またはコーティングされる。   The SCR 23C has, for example, a cylindrical shape and includes a honeycomb carrier made of ceramic. The honeycomb wall surface is supported or coated with a catalyst such as zeolite or vanadium.

上記のようなＳＣＲ２３Ｃは、排気管２１において、上記ＤＰＦ２３Ｂの下流側に配置される。また、排気管２１においてＤＰＦ２３ＢとＳＣＲ２３Ｃとの間には、還元剤としての尿素水が、尿素水インジェクタ２５により噴射され、ＤＯＣ２３ＡおよびＤＰＦ２３Ｂを通過した排気ガスに供給される。その結果、尿素水がアンモニアに加水分解される。アンモニアを含む排気ガスがＳＣＲ２３Ｃを通過中、触媒の作用により窒素酸化物（いわゆるＮＯｘ）が窒素と水に反応する（還元反応）。これにより、排気ガス中の窒素酸化物が浄化される。   The SCR 23C as described above is disposed in the exhaust pipe 21 on the downstream side of the DPF 23B. Further, urea water as a reducing agent is injected between the DPF 23B and the SCR 23C in the exhaust pipe 21 by the urea water injector 25 and supplied to the exhaust gas that has passed through the DOC 23A and the DPF 23B. As a result, urea water is hydrolyzed to ammonia. While exhaust gas containing ammonia passes through the SCR 23C, nitrogen oxide (so-called NOx) reacts with nitrogen and water (reduction reaction) by the action of the catalyst. Thereby, nitrogen oxides in the exhaust gas are purified.

ここで、加水分解は、ＳＣＲ２３Ｃを通過する排気ガスの温度が所定温度以上で起こる。したがって、尿素水インジェクタ２５は、ＳＣＲ２３Ｃに流入する排気ガスの温度が所定温度以上の場合に、尿素水を排気管２１内の排気ガスに供給することが好ましい。ここで、尿素水の噴射はＤＣＵ（図示せず）により制御される。なお、所定温度は、排気系２０の設計開発段階での実験・シミュレーション等により、アンモニアとＮＯｘとの反応温度等を考慮しつつ適宜適切に定められる。   Here, the hydrolysis occurs when the temperature of the exhaust gas passing through the SCR 23C is equal to or higher than a predetermined temperature. Therefore, the urea water injector 25 preferably supplies urea water to the exhaust gas in the exhaust pipe 21 when the temperature of the exhaust gas flowing into the SCR 23C is equal to or higher than a predetermined temperature. Here, the injection of urea water is controlled by a DCU (not shown). Note that the predetermined temperature is appropriately determined appropriately in consideration of the reaction temperature between ammonia and NOx by experiments and simulations at the design and development stage of the exhaust system 20.

ＲＤＯＣ２３Ｄは、後段酸化触媒であって、ＤＯＣ２３Ａと同様の構成を有しており、排気管２１においてＳＣＲ２３Ｃの直ぐ下流に配置される。   The RDOC 23D is a rear-stage oxidation catalyst and has a configuration similar to that of the DOC 23A, and is disposed in the exhaust pipe 21 immediately downstream of the SCR 23C.

ＲＤＯＣ２３Ｄは、主として、ＳＣＲ２３Ｃにおいて還元反応に使用されずにスリップしてきたアンモニアが大気中に放出されないように、スリップしてきたアンモニアを酸化し除去する。それ以外にも、ＲＤＯＣ２３Ｄは、ＳＣＲ２３Ｃと同様の機能を有する場合もある。   The RDOC 23D mainly oxidizes and removes the slipped ammonia so that ammonia that is slipped without being used in the reduction reaction in the SCR 23C is not released into the atmosphere. In addition, the RDOC 23D may have the same function as the SCR 23C.

以上の各後処理装置で排気ガスを処理して生成される水、窒素、二酸化炭素は、マフラー（図示せず）等を介して、大気中に排出される。   Water, nitrogen, and carbon dioxide generated by treating the exhaust gas with each of the above aftertreatment devices are discharged into the atmosphere through a muffler (not shown) or the like.

ところで、内燃機関１０の低負荷運転時など排気ガスの温度が低い場合、尿素水の噴射量が異常に多い場合、排気ガスの流量が少ないのに尿素水の噴射が連続した場合などには、尿素水の加水分解が不十分となり、排気管２１内、特に尿素水インジェクタ２５の噴口部（取り付け部）周辺に、尿素水が加水分解する際に生じるシアヌル酸などに代表される白色生成物が堆積する。排気管２１内に白色生成物が堆積すると、例えば排気管２１内が閉塞し、所望の排気ガス浄化処理が実施できないおそれがある。   By the way, when the temperature of the exhaust gas is low, such as during low-load operation of the internal combustion engine 10, when the injection amount of urea water is abnormally large, or when the urea water injection continues even though the flow rate of the exhaust gas is small, The hydrolysis of urea water becomes insufficient, and a white product typified by cyanuric acid generated when urea water is hydrolyzed in the exhaust pipe 21, particularly around the nozzle hole (attachment portion) of the urea water injector 25. accumulate. If a white product accumulates in the exhaust pipe 21, for example, the inside of the exhaust pipe 21 may be blocked, and a desired exhaust gas purification process may not be performed.

図２は、本実施の形態における尿素水インジェクタ２５の噴口部周辺２９の部分拡大図である。尿素水インジェクタ２５の噴口部周辺２９では、排気ガスの流れが滞留しやすく、尿素水インジェクタ２５から噴射された尿素水も滞留しやすい。その結果、噴口部周辺２９には、尿素水の加水分解が不十分な場合に、白色生成物が堆積しやすい。また、排気ガスの流速が遅いことから、噴口部周辺２９に堆積した白色生成物を掻き取ることは難しい。   FIG. 2 is a partially enlarged view of the vicinity 29 of the injection nozzle portion of the urea water injector 25 in the present embodiment. In the vicinity 29 of the injection port portion of the urea water injector 25, the flow of the exhaust gas tends to stay, and the urea water injected from the urea water injector 25 also tends to stay. As a result, a white product is likely to deposit in the vicinity of the nozzle part 29 when hydrolysis of urea water is insufficient. Further, since the exhaust gas flow rate is slow, it is difficult to scrape off the white product deposited around the nozzle hole portion 29.

そこで、本実施の形態では、屈曲部２１ａにおける排気ガスの流れを改善するため、排気ガスの流れ方向において排気管２１のうち屈曲部２１ａの上流側には、排気管２１の内径よりも小さい内径を有する内管２７が配置されて二重管構造としている。本実施の形態では、内管２７は整流パイプである。   Therefore, in the present embodiment, in order to improve the flow of exhaust gas in the bent portion 21a, an inner diameter smaller than the inner diameter of the exhaust pipe 21 is located upstream of the bent portion 21a in the exhaust pipe 21 in the exhaust gas flow direction. An inner tube 27 having a double-pipe structure is provided. In the present embodiment, the inner pipe 27 is a rectifying pipe.

図２において、実線矢印Ａは、内管２７の内側を通過し、尿素水インジェクタ２５の噴口部周辺２９に向かう排気ガスの流れを示す。本実施の形態では、内管２７の内側を通過した排気ガスが尿素水インジェクタ２５の噴口部周辺２９により向かいやすくする観点から、排気ガスの流れ方向において内管２７の後端面には、側面視で斜めに切断した形状の傾斜面が形成されている。噴口部周辺２９に向かう排気ガスは、流れが一様であり、流速が速くなる。そのため、尿素水インジェクタ２５の噴口部周辺２９では、排気ガスの流れは滞留しにくく、尿素水インジェクタ２５から噴射された尿素水も滞留しにくい。仮に、尿素水の加水分解が不十分な場合に、噴口部周辺２９に白色生成物が堆積した場合でも、排気ガスの流速が速いことから、噴口部周辺２９に堆積した白色生成物は容易に掻き取られる。   In FIG. 2, a solid line arrow A indicates the flow of exhaust gas that passes through the inside of the inner tube 27 and travels toward the nozzle hole periphery 29 of the urea water injector 25. In the present embodiment, from the viewpoint of facilitating the exhaust gas that has passed through the inner side of the inner pipe 27 to the nozzle hole periphery 29 of the urea water injector 25, the rear end surface of the inner pipe 27 in the exhaust gas flow direction is viewed from the side. An inclined surface having a shape cut obliquely is formed. The exhaust gas traveling toward the nozzle hole periphery 29 has a uniform flow and a high flow velocity. For this reason, the flow of the exhaust gas hardly stays in the vicinity 29 of the injection port portion of the urea water injector 25, and the urea water injected from the urea water injector 25 also hardly stays. Even if the hydrolysis of urea water is insufficient, even when a white product is deposited around the nozzle hole 29, the exhaust gas flow rate is high, so the white product deposited around the nozzle hole 29 is easily It is scraped off.

実線矢印Ｂは、噴口部周辺２９を通過した後、下流側に向かう排気ガスの流れを示す。点線矢印Ｃは、排気管２１と内管２７との間に隙間が設けられていることにより、内管２７の外周を回り込み、尿素水インジェクタ２５の下流側に導きられる排気ガスの流れを示す。一点鎖線矢印Ｄは、実線矢印Ｂに対応する排気ガスと、点線矢印Ｃに対応する排気ガスとが合流した後の排気ガスの流れを示す。実線矢印Ｂおよび一点鎖線矢印Ｄに対応する排気ガスによって、尿素水インジェクタ２５から噴射された尿素水は、ＳＣＲ２３Ｃに向けてスムーズに送られる。   A solid line arrow B indicates the flow of exhaust gas that passes through the nozzle hole periphery 29 and then travels downstream. A dotted arrow C indicates the flow of the exhaust gas that goes around the outer periphery of the inner pipe 27 and is led downstream of the urea water injector 25 by providing a gap between the exhaust pipe 21 and the inner pipe 27. An alternate long and short dash line arrow D indicates the flow of the exhaust gas after the exhaust gas corresponding to the solid line arrow B and the exhaust gas corresponding to the dotted line arrow C merge. The urea water injected from the urea water injector 25 by the exhaust gas corresponding to the solid line arrow B and the one-dot chain line arrow D is smoothly sent toward the SCR 23C.

以上詳しく説明したように、本実施の形態では、排気ガス浄化システム（排気系２０）は、内燃機関１０の排気通路を構成する排気管２１に、選択還元型触媒装置（ＳＣＲ２３Ｃ）と、尿素水を噴射する尿素水インジェクタ２５とを備えて構成される。そして、排気管２１を通過する排気ガスの流れ方向において排気管２１のうち選択還元型触媒装置の上流側には、尿素水インジェクタ２５が設けられた屈曲部２１ａが形成され、当該流れ方向において排気管２１のうち屈曲部２１ａの上流側には、排気管２１の内径よりも小さい内径を有する内管２７が配置されており、排気管２１と内管２７との間に排気ガスが通過する隙間を有する。   As described above in detail, in the present embodiment, the exhaust gas purification system (exhaust system 20) includes the selective reduction catalyst device (SCR 23C), the urea water, and the exhaust pipe 21 constituting the exhaust passage of the internal combustion engine 10. And a urea water injector 25 for injecting water. A bent portion 21a provided with a urea water injector 25 is formed on the upstream side of the selective reduction catalyst device in the exhaust pipe 21 in the flow direction of the exhaust gas passing through the exhaust pipe 21, and the exhaust gas is exhausted in the flow direction. An inner pipe 27 having an inner diameter smaller than the inner diameter of the exhaust pipe 21 is disposed on the upstream side of the bent portion 21 a of the pipe 21, and a gap through which exhaust gas passes between the exhaust pipe 21 and the inner pipe 27. Have

このように構成した本実施の形態によれば、噴口部周辺２９に向かう排気ガスは、流れが一様であり、流速が速くなるため、尿素水インジェクタ２５の噴口部周辺２９では、排気ガスの流れは滞留しにくく、尿素水インジェクタ２５から噴射された尿素水も滞留しにくい。仮に、尿素水の加水分解が不十分な場合に、噴口部周辺２９に白色生成物が堆積した場合でも、排気ガスの流速が速いことから、噴口部周辺２９に堆積した白色生成物は容易に掻き取られる。その結果、尿素水インジェクタ２５の噴口部周辺２９に白色生成物が堆積することを防止することができる。また、排気管２１と内管２７との間に隙間が設けられていることにより、内管２７の外周を回り込み、尿素水インジェクタ２５の下流側に直接導きられる排気ガスの流れが生まれ、その流れによって、尿素水インジェクタ２５から噴射された尿素水は、ＳＣＲ２３Ｃに向けてスムーズに送られる。以上より、白色生成物の堆積を防止して所望の排気ガス浄化処理を実施することができる。   According to the present embodiment configured as described above, the exhaust gas traveling toward the nozzle hole periphery 29 has a uniform flow rate and a high flow velocity. Therefore, in the nozzle hole periphery 29 of the urea water injector 25, The flow hardly stays, and the urea water injected from the urea water injector 25 also hardly stays. Even if the hydrolysis of urea water is insufficient, even when a white product is deposited around the nozzle hole 29, the exhaust gas flow rate is high, so the white product deposited around the nozzle hole 29 is easily It is scraped off. As a result, it is possible to prevent the white product from being deposited around the nozzle hole portion 29 of the urea water injector 25. In addition, since a gap is provided between the exhaust pipe 21 and the inner pipe 27, an exhaust gas flow that flows around the outer periphery of the inner pipe 27 and is directly guided to the downstream side of the urea water injector 25 is generated. Thus, the urea water injected from the urea water injector 25 is smoothly fed toward the SCR 23C. As described above, it is possible to prevent the white product from being deposited and perform a desired exhaust gas purification process.

また、本実施の形態では、排気ガスの流れ方向において内管２７の後端面には、側面視で斜めに切断した形状の傾斜面が形成されている。この構成により、内管２７の内側を通過した排気ガスが尿素水インジェクタ２５の噴口部周辺２９に向けて、より向かいやすくすることができる。   In the present embodiment, the rear end surface of the inner tube 27 in the exhaust gas flow direction is formed with an inclined surface that is cut obliquely in a side view. With this configuration, the exhaust gas that has passed through the inner side of the inner pipe 27 can be more easily directed toward the nozzle hole periphery 29 of the urea water injector 25.

なお、上記実施の形態は、何れも本発明を実施するにあたっての具体化の一例を示したものに過ぎず、これらによって本発明の技術的範囲が限定的に解釈されてはならないものである。すなわち、本発明はその要旨、またはその主要な特徴から逸脱することなく、様々な形で実施することができる。例えば、排気ガスの流れ方向において内管２７の後端面には、側面視で斜めに切断した形状の傾斜面が形成されている例について説明したが、内管２７の後端面の形状にこれに限らない。   The above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. That is, the present invention can be implemented in various forms without departing from the gist or the main features thereof. For example, an example has been described in which the rear end surface of the inner tube 27 in the exhaust gas flow direction is formed with an inclined surface that is obliquely cut when viewed from the side. Not exclusively.

本発明は、尿素水インジェクタの噴口部周辺に白色生成物が堆積することを防止することが可能な排気ガス浄化システムとして有用である。   INDUSTRIAL APPLICABILITY The present invention is useful as an exhaust gas purification system that can prevent white products from accumulating around the nozzle part of a urea water injector.

１ 車両
１０ 内燃機関
１１ 燃焼室
１３ 燃料噴射インジェクタ
１５ 吸気バルブ
１７ 排気バルブ
１９ ピストン
２０ 排気系
２１ 排気管
２１ａ 屈曲部
２３Ａ ＤＯＣ
２３Ｂ ＤＰＦ
２３Ｃ ＳＣＲ
２３Ｄ ＲＤＯＣ
２５ 尿素水インジェクタ（還元剤インジェクタ）
２７ 内管 DESCRIPTION OF SYMBOLS 1 Vehicle 10 Internal combustion engine 11 Combustion chamber 13 Fuel injection injector 15 Intake valve 17 Exhaust valve 19 Piston 20 Exhaust system 21 Exhaust pipe 21a Bending part 23A DOC
23B DPF
23C SCR
23D RDOC
25 Urea water injector (reducing agent injector)
27 Inner pipe

Claims (3)

内燃機関の排気通路を構成する排気管に、選択還元型触媒装置と、還元剤を噴射する還元剤インジェクタとを備えて構成される排気ガス浄化システムであって、
前記排気管を通過する排気ガスの流れ方向において前記排気管のうち前記選択還元型触媒装置の上流側には、前記還元剤インジェクタが設けられた屈曲部が形成され、
前記流れ方向において前記排気管のうち前記屈曲部の上流側には、当該排気管の内径よりも小さい内径を有する内管が配置されており、当該排気管と当該内管との間に前記排気ガスが通過する隙間を有する、
排気ガス浄化システム。 An exhaust gas purification system comprising a selective reduction catalyst device and a reducing agent injector for injecting a reducing agent in an exhaust pipe constituting an exhaust passage of an internal combustion engine,
A bent portion provided with the reducing agent injector is formed on the upstream side of the selective reduction catalyst device in the exhaust pipe in the flow direction of the exhaust gas passing through the exhaust pipe,
An inner pipe having an inner diameter smaller than the inner diameter of the exhaust pipe is disposed on the upstream side of the bent portion of the exhaust pipe in the flow direction, and the exhaust pipe is disposed between the exhaust pipe and the inner pipe. Having a gap through which the gas passes,
Exhaust gas purification system. 前記流れ方向において前記内管の後端面には、側面視で斜めに切断した形状の傾斜面が形成されている、
請求項１に記載の排気ガス浄化システム。 In the flow direction, an inclined surface having a shape cut obliquely in a side view is formed on the rear end surface of the inner tube.
The exhaust gas purification system according to claim 1. 前記屈曲部の断面形状は、Ｓ字形状またはクランク形状である、
請求項１または２に記載の排気ガス浄化システム。 The cross-sectional shape of the bent portion is an S shape or a crank shape.
The exhaust gas purification system according to claim 1 or 2.
JP2017127243A 2017-06-29 2017-06-29 Exhaust emission control system Pending JP2019011684A (en)

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US9528414B2 (en) * 2013-10-14 2016-12-27 Cummins Emission Solutions, Inc. Diesel exhaust fluid deposit mitigation
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