WO2018198344A1 - Dispositif d'épuration de gaz d'échappement - Google Patents

Dispositif d'épuration de gaz d'échappement Download PDF

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Publication number
WO2018198344A1
WO2018198344A1 PCT/JP2017/017025 JP2017017025W WO2018198344A1 WO 2018198344 A1 WO2018198344 A1 WO 2018198344A1 JP 2017017025 W JP2017017025 W JP 2017017025W WO 2018198344 A1 WO2018198344 A1 WO 2018198344A1
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WO
WIPO (PCT)
Prior art keywords
exhaust gas
flow passage
casing
purification device
exhaust
Prior art date
Application number
PCT/JP2017/017025
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English (en)
Japanese (ja)
Inventor
勇人 相澤
知秀 高屋
佑 江原
智美 浦濱
森　仁志
Original Assignee
東京濾器株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 東京濾器株式会社 filed Critical 東京濾器株式会社
Priority to PCT/JP2017/017025 priority Critical patent/WO2018198344A1/fr
Priority to JP2019515045A priority patent/JPWO2018198344A1/ja
Publication of WO2018198344A1 publication Critical patent/WO2018198344A1/fr

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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
    • F01N3/24—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
    • F01N3/28—Construction of catalytic reactors

Definitions

  • the present invention relates to an exhaust purification device, and is particularly suitable for an exhaust purification device that purifies exhaust gas discharged from a diesel engine.
  • Exhaust gas discharged from an internal combustion engine contains particulate matter (PM) and nitrogen oxides (NOx), which are harmful substances. Therefore, it is required to purify the exhaust gas discharged from the internal combustion engine and remove or reduce PM and NOx from the exhaust gas.
  • an exhaust gas purification apparatus combining a DPF system and a urea SCR system has been developed and put into practical use.
  • the DPF system is a device for removing or reducing PM from exhaust gas, and an oxidation catalyst (DOC: Diesel Oxidation Catalyst for oxidizing NOx in exhaust gas discharged from an internal combustion engine (diesel engine). ) And a particulate filter (DPF: Diesel Particulate Filter) for collecting and burning (oxidizing) PM in the exhaust gas.
  • DOC Diesel Oxidation Catalyst for oxidizing NOx in exhaust gas discharged from an internal combustion engine (diesel engine).
  • DPF Diesel Particulate Filter
  • the urea SCR system is a device for removing or reducing NOx from exhaust gas using a selective reduction reaction between NOx and ammonia, and selective reduction for reducing and removing NOx in contact with a reducing agent.
  • a catalyst (SCR: Selective Catalytic Reduction) and an ammonia slip catalyst are provided.
  • a return flow passage having a smaller diameter than the upstream side is formed concentrically with the exhaust gas flow passage, and a part of the exhaust gas is folded to surround the DPF. I try to distribute it. And since the exhaust gas which distribute
  • an exhaust gas purification device that purifies exhaust gas from an internal combustion engine by providing a flow passage in the casing and sequentially arranging catalysts such as DOC, DPF, SCR, etc. in the flow passage and sequentially circulating these catalysts. It has been.
  • catalysts such as DOC, DPF, SCR, etc.
  • an object of the present invention is to provide an exhaust purification apparatus that can avoid the complication of the structure and is excellent in heat insulation and heat retention.
  • an exhaust emission control device includes: An exhaust purification device for purifying exhaust gas discharged from an internal combustion engine, A flow passage communicating with the exhaust gas inlet; A casing for accommodating the flow passage, The flow path is An oxidation catalyst for oxidizing nitrogen oxides in the exhaust gas; A particulate filter disposed on the downstream side of the oxidation catalyst for collecting and removing particulate components in the exhaust gas; A selective reduction catalyst disposed on the downstream side of the particulate filter, for reducing and removing the nitrogen oxides in contact with a reducing agent selected from a urea component or an ammonia component,
  • the casing is provided with a discharge port for the exhaust gas, and a space formed between the inner wall of the casing and the flow passage is filled with exhaust gas discharged from the flow passage. It is characterized by that.
  • the flow path further includes a new oxidation catalyst that is disposed on the downstream side of the selective reduction catalyst and oxidizes the reducing agent that is discharged from the selective reduction catalyst.
  • an exhaust purification device that can avoid the complication of the structure and is excellent in heat insulation and heat retention.
  • FIG. 1 is a schematic perspective view showing an exhaust gas purification apparatus according to the present embodiment partially through. It is sectional drawing with which it uses for description of the flow of the exhaust gas in the exhaust gas purification apparatus of FIG. It is a top view which shows the exhaust gas purification apparatus of FIG. It is a bottom view which shows the exhaust gas purification apparatus of FIG.
  • FIG. 4 is a side view showing the exhaust emission control device of FIG. 3 as viewed from the right side of the drawing.
  • FIG. 4 is a side view showing the exhaust purification device of FIG. 3 as viewed from the left side of the drawing.
  • FIG. 7 is a cross-sectional view showing a cross section taken along line AA in the exhaust emission control device of FIG. 6.
  • FIG. 7 is a cross-sectional view showing a cross section taken along line BB in the exhaust emission control device of FIG. 6.
  • FIG. 6 is a cross-sectional view showing a cross section taken along the line CC in the exhaust emission control device of FIG. 5.
  • FIG. 7 is a cross-sectional view showing a cross section taken along the arrow DD in the exhaust emission control device of FIG. 6.
  • FIG. 7 is a cross-sectional view showing a cross section taken along the line EE in the exhaust emission control device of FIG. 6.
  • the exhaust emission control device 1 of the present embodiment includes a first flow passage 2 that communicates with an inflow port GI of exhaust gas discharged from an internal combustion engine (in this case, a diesel engine) (not shown). , A second flow passage 3 communicating with the first flow passage 2, and a substantially box-shaped casing 4 accommodating the first and second flow passages 2, 3.
  • the first and second flow passages 2 and 3 each have a cylindrical shape, but the present invention is not limited to this.
  • the exhaust gas outlet GO in the casing 4 can be provided at an arbitrary position according to the vehicle to be mounted.
  • the first flow passage 2 is disposed on the downstream side of the DOC 21 and an oxidation catalyst (DOC) 21 for oxidizing nitrogen oxide (NOx) in the exhaust gas.
  • DOC oxidation catalyst
  • DPF particulate filter
  • an upstream introduction portion 20 described later is disposed on the upstream side of the DOC 21 in the first flow passage 2.
  • the upstream introduction part 20 is for diffusing exhaust gas flowing in from the inlet GI in the diameter direction of the DOC 21.
  • the second flow passage 3 has a selective reduction catalyst for reducing and removing nitrogen oxides (NOx) by contacting with a reducing agent selected from a urea component or an ammonia component.
  • SCR nitrogen oxides
  • 31 and 32 are installed.
  • an NH 3 slip 33 as a new oxidation catalyst for oxidizing the reducing agent discharged from the SCR 32 is disposed further downstream of the downstream SCR 32.
  • the reducing agent discharged (slips) without being completely reacted with the exhaust gas in the SCRs 31 and 32 can be reliably oxidized, and the slip phenomenon can be prevented.
  • the NH 3 slip 33 is not essential, and the NH 3 slip 33 may be omitted.
  • the first flow passage 2 and the second flow passage 3 are arranged in parallel to each other so that their cross sections are aligned in a diagonal direction in the side wall cross section of the casing 4. More specifically, they are arranged at substantially corners facing each other in the side wall cross section. Moreover, the 1st flow path 2 and the 2nd flow path 3 are connected via the communication part 5 provided with the dosing 51 which is a reducing agent spray part for supplying a reducing agent.
  • the communication portion 5 has a substantially U-shape as a whole, a dosing 51 that communicates with the DPF 22 of the first flow passage 2, and an upstream side that communicates with the dosing 51.
  • the downstream side diffusion portion 54 and the downstream side introduction portion 55 that communicates with the SCR 31 of the second flow passage 3 are provided.
  • An opening 22 a for exhaust gas exhaust to the dosing 51 is provided on the outer periphery of the downstream end of the DPF 22.
  • the first flow passage 2 and the second flow passage 3 are connected in a substantially S shape by the communication portion 5.
  • the length of the flow passage can be increased without increasing the overall length of the exhaust purification device 1, and spraying is performed in the dosing 51. It is possible to ensure the diffusibility of the reducing agent.
  • the introduction portion 20 of the first flow passage 2 includes a pipe-like inlet GI through which exhaust gas flows into the first flow passage 2 from the side, and an exhaust gas inflow side end surface of the DOC 21. And an overhanging portion 20b covering the.
  • the introduction part 20 has a shape that extends from the inflow port GI to the connection end part 20a on the DOC 21 side in the overhang part 20b to a position near the diameter on the outer periphery of the DOC 21.
  • the projecting portion 20b has a shape in which a portion facing the DOC 21 swells toward the side opposite to the DOC 21 side (that is, the outer side of the casing 4).
  • projection part 20b of the casing 4 has comprised the shape bulging outward so that the said overhang
  • the introduction unit 20 is provided with a baffle plate 201 (in this case, cylindrical) along the outer diameter of the DOC 21.
  • the baffle plate 201 is configured as a punching metal having one surface facing the inlet GI side having a number of punching holes 201a.
  • the exhaust gas flowing in from the inlet GI disposed on the side of the first flow passage 2 passes through the punching hole 201a of the baffle plate 201 (arrow L1a in FIG. 10) and the baffle plate 201. By distributing it over the route (arrow L1b in FIG. 10), it can be uniformly diffused in the diameter direction of the DOC 21.
  • a space is formed between the inner wall of the casing 4 and the first and second flow passages 2 and 3 including the communication portion 5, and this space is formed by the DOC 21 and the DPF 22. , SCR21, 32, etc., function as an air layer X for heat insulation (heat insulation).
  • the exhaust gas discharged from the second flow passage 3 circulates in the air layer X and is filled until it is discharged from the discharge port GO, as will be described in detail later. .
  • the urea water injected and supplied from the dosing 51 is upstream through the lower opening 22a in the upstream diffusion portion 52, the connection portion 53, and the downstream diffusion portion 54 of the communication portion 5 folded back in a substantially U shape.
  • the exhaust gas flow after passing through the DPF 22 (arrow L3 in FIGS. 8 and 10) flowing into the side diffusion portion 52 flows while forming a swirl flow along the inner wall surface of the communication portion 5 (FIGS. 2 and 8). Arrow L4). That is, the exhaust gas that has passed through the DOC 21 and the DPF 22 is stirred and mixed with the urea water that has formed a swirling flow when passing through the vicinity of the communicating portion 5. At that time, the exhaust gas stirred and mixed with the urea water is forced to change its flow direction while swirling in the vicinity of the connection portion 53 and is uniformly dispersed in the downstream diffusion portion 54.
  • the exhaust gas is blocked by the wall surface of the downstream introduction portion 55, and then flows into the SCR 31 of the second flow passage 3 while turning (arrows L5 and L6 in FIGS. 2 and 8), and is uniformly dispersed. In this state, it passes through the SCR 32 and the NH 3 slip 33 (arrow L7 in FIGS. 2 and 8).
  • NOx including NO 2
  • urea water and NH 3 remaining in the exhaust gas without being consumed by the SCRs 31 and 32 are adsorbed by the NH 3 slip 33 and removed from the exhaust gas, or oxidized and purified by the NH 3 slip 33 to form N 2 .
  • the exhaust gas purified by passing through the SCRs 31 and 32 and the NH 3 slip 33 is air formed between the inner wall of the casing 4 and the first and second flow passages 2 and 3 including the communication part 5. It flows out to the layer X (arrow L10 shown with the broken line of FIG. 1, FIG. 2).
  • the exhaust gas from the internal combustion engine circulates only in the flow passage provided in the casing, so that the exhaust gas does not circulate in the space other than the flow passage in the casing.
  • it was not used for heat insulation.
  • heat insulation was performed only in the air layer provided in the casing.
  • the high temperature exhaust gas that has been purified by passing through the SCRs 31 and 32 and the NH 3 slip 33 is circulated through the air layer X in the casing 4.
  • the temperature of can be raised, and the further heat insulation (heat retention) effect can be acquired.
  • circulated the air layer X flows out of the casing 4 (namely, exhaust gas purification device 1) through the discharge port GO formed in arbitrary positions with respect to the casing 4.
  • the casing 4 is provided with a flow passage for circulating the exhaust gas discharged from the diesel engine, and a catalyst such as DOC21, DPF22, and SCR31, 32 disposed in the flow passage.
  • a catalyst such as DOC21, DPF22, and SCR31, 32 disposed in the flow passage.
  • exhaust gas purified by passing through the DOC 21, DPF 22 and SCRs 31, 32 in order is supplied to the first and second circulations including the inner wall of the casing 4 and the communication portion 5.
  • the structure is complicated by a simple structure in which it flows out to the air layer X formed between the passages 2 and 3 and the heat of the exhaust gas is used to insulate the air layer X and thus the catalyst. Therefore, it is possible to provide the exhaust emission control device 1 that can avoid the shift to heat and is excellent in heat insulation and heat retention.
  • the second flow passage 3 is arranged on the downstream side of the SCR 32, and further includes an NH 3 slip 33 as a new oxidation catalyst for oxidizing the urea water discharged from the SCR 32. It is possible to reliably oxidize the reducing agent that does not react with the exhaust gas and is discharged (slips) to prevent the slip phenomenon.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

Ce dispositif de purification de gaz d'échappement (1) comprend: des passages d'écoulement (2,3) qui communiquent avec une entrée de flux de gaz d'échappement (GI); et un boîtier (4) qui loge les passages d'écoulement (2,3) et qui est pourvu d'une sortie de décharge de gaz d'échappement (GO) à une position arbitraire. Chaque passage d'écoulement (2, 3) comprend: un DOC (21); un filtre à particules diesel (DPF) (22) disposé sur le côté en aval du DOC; et des SCR (31, 32) disposés sur le côté en aval du filtre à particules diesel (DPF). Le gaz d'échappement déchargé depuis le passage d'écoulement (3) est mis en circulation et est rempli dans une couche d'air X qui est formée entre une paroi interne du boîtier (4) et les passages d'écoulement (2, 3). Grâce à cette configuration, une augmentation de la complexité structurelle peut être évitée et une excellente isolation thermique et une excellente rétention de chaleur peuvent être obtenues dans ce dispositif de purification de gaz d'échappement (1).
PCT/JP2017/017025 2017-04-28 2017-04-28 Dispositif d'épuration de gaz d'échappement WO2018198344A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/JP2017/017025 WO2018198344A1 (fr) 2017-04-28 2017-04-28 Dispositif d'épuration de gaz d'échappement
JP2019515045A JPWO2018198344A1 (ja) 2017-04-28 2017-04-28 排気浄化装置

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2017/017025 WO2018198344A1 (fr) 2017-04-28 2017-04-28 Dispositif d'épuration de gaz d'échappement

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WO2018198344A1 true WO2018198344A1 (fr) 2018-11-01

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003120260A (ja) * 2001-10-18 2003-04-23 Hino Motors Ltd 排気浄化装置
US20100242450A1 (en) * 2009-03-26 2010-09-30 Marcus Werni Exhaust gas-treating device
JP2016186229A (ja) * 2015-03-27 2016-10-27 ダイハツ工業株式会社 排気ガス浄化装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003120260A (ja) * 2001-10-18 2003-04-23 Hino Motors Ltd 排気浄化装置
US20100242450A1 (en) * 2009-03-26 2010-09-30 Marcus Werni Exhaust gas-treating device
JP2016186229A (ja) * 2015-03-27 2016-10-27 ダイハツ工業株式会社 排気ガス浄化装置

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