WO2014156354A1 - Exhaust gas purifying device for internal combustion engine - Google Patents

Exhaust gas purifying device for internal combustion engine Download PDF

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Publication number
WO2014156354A1
WO2014156354A1 PCT/JP2014/053423 JP2014053423W WO2014156354A1 WO 2014156354 A1 WO2014156354 A1 WO 2014156354A1 JP 2014053423 W JP2014053423 W JP 2014053423W WO 2014156354 A1 WO2014156354 A1 WO 2014156354A1
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WO
WIPO (PCT)
Prior art keywords
reducing agent
exhaust
injection valve
internal combustion
combustion engine
Prior art date
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PCT/JP2014/053423
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French (fr)
Japanese (ja)
Inventor
成弘 大野
Original Assignee
ボッシュ株式会社
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Publication date
Application filed by ボッシュ株式会社 filed Critical ボッシュ株式会社
Priority to JP2015508162A priority Critical patent/JPWO2014156354A1/en
Publication of WO2014156354A1 publication Critical patent/WO2014156354A1/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
    • 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]
    • F01N3/208—Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
    • 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
    • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/02—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a heat exchanger
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/10—Adding substances to exhaust gases the substance being heated, e.g. by heating tank or supply line of the added substance
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/11—Adding substances to exhaust gases the substance or part of the dosing system being cooled
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1453—Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
    • 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

Definitions

  • the present invention relates to an exhaust purification device for purifying nitrogen oxides in exhaust gas of an internal combustion engine.
  • Nitrogen oxides are contained in exhaust gas from internal combustion engines such as diesel engines.
  • a reduction catalyst disposed in the exhaust passage of the internal combustion engine, and a reducing agent supply device for injecting a liquid reducing agent such as a urea aqueous solution upstream of the reduction catalyst
  • an exhaust emission control device including This exhaust gas purification apparatus efficiently reduces NO x and ammonia in exhaust gas in a reduction catalyst to decompose NO x into nitrogen, water, and the like.
  • the reducing agent supply device uses a reducing agent injection valve attached to the exhaust pipe to inject the liquid reducing agent into the exhaust passage, but the reducing agent injection valve must be of the solenoid valve type. However, it is necessary to protect from exhaust heat transmitted through the exhaust pipe. Further, when an aqueous urea solution is used as the liquid reducing agent, when the aqueous urea solution attached to the tip of the reducing agent injection valve is heated and urea crystallizes, the reducing agent injection valve is clogged and the liquid reducing agent is injected. There is a risk that it will not be possible. Therefore, the reducing agent injection valve is fixed to the exhaust pipe by using a heat radiation fin that promotes natural heat dissipation or a housing (cooling jacket) provided with a cooling water passage through which cooling water can flow (for example, (See Patent Document 1).
  • the cooling function described above works relatively efficiently during the operation of the internal combustion engine, the function stops after the internal combustion engine stops, and the reducing agent injection valve may be heated by residual exhaust heat. is there.
  • the exhaust purification device as described above is also used in the exhaust system of an internal combustion engine for non-traveling vehicles such as construction machinery and agricultural machinery.
  • non-traveling vehicles unlike traveling vehicles such as passenger cars and commercial vehicles, the space for piping and various devices is limited, and the entire exhaust emission control device including the reducing agent injection valve is stored in the engine room. There are many. Therefore, since the reducing agent injection valve becomes more susceptible to heat, the necessity for reducing the influence of heat on the reducing agent injection valve becomes higher.
  • an object of the present invention is to efficiently reduce the heat transmitted to the reducing agent injection valve in the exhaust gas purification apparatus for an internal combustion engine.
  • an exhaust purification device that is provided in an exhaust passage of an internal combustion engine and purifies nitrogen oxides in exhaust using a liquid reducing agent, the reduction catalyst provided in the exhaust passage, And a reducing agent injection valve for injecting the liquid reducing agent into the exhaust passage on the upstream side of the reduction catalyst, wherein the exhaust pipe body is provided with a branch pipe, and the liquid reducing agent A reducing agent injection valve for injecting the reducing agent is attached to the branch pipe, and between the branch position of the branch pipe and the exhaust pipe main body and the attachment position of the reducing agent injection valve,
  • An exhaust gas purification apparatus for an internal combustion engine characterized by including a cooling means for reducing the transmission of exhaust heat can solve the above-described problems.
  • the reducing agent injection valve is attached to the branch pipe branched from the exhaust pipe main body, and the cooling is performed from the branch position of the branch pipe to the attachment position of the reducing agent injection valve. Since the means is provided, it is possible to reduce the exhaust heat transmitted to the reducing agent injection valve before the attachment position of the reducing agent injection valve. Therefore, the amount of heat transmitted to the reducing agent injection valve can be reduced, and thermal damage to the reducing agent injection valve and crystallization of the liquid reducing agent can be prevented.
  • the cooling means is a cooling water passage through which the cooling water of the internal combustion engine can flow.
  • the cooling water maintained at the temperature of about 90 degreeC, for example, without using another cooling means.
  • the cooling water passage is provided in a cooling water circulation member interposed between the branch pipe and the reducing agent injection valve.
  • the cooling water passage is provided at an end portion of the branch pipe and is provided at an attachment flange portion to which the reducing agent injection valve is attached.
  • the cooling water passage is a cooling water pipe wound around the outer periphery of the branch pipe.
  • the reducing agent injection valve is held by a housing and attached to the branch pipe, and the cooling water of the internal combustion engine can be circulated in the housing. It is preferable that Thus, by allowing the coolant to flow through the housing for attaching the reducing agent injection valve to the branch pipe, the exhaust heat transmitted to the reducing agent injection valve can be further reduced. Thermal damage and crystallization of the liquid reducing agent can be prevented.
  • FIG. 1 is an overall view showing an example of an exhaust purification device according to an embodiment of the present invention. It is a figure shown in order to demonstrate the cooling means of the exhaust gas purification apparatus concerning the 1st Embodiment of this invention. It is a figure shown in order to demonstrate the cooling means of the exhaust gas purification apparatus concerning the 2nd Embodiment of this invention. It is a figure shown in order to demonstrate a cooling water distribution member. It is a figure shown in order to demonstrate the cooling means of the exhaust gas purification apparatus concerning the 3rd Embodiment of this invention.
  • FIG. 1 is a diagram shown for explaining an example of the overall configuration of an exhaust purification device (hereinafter simply referred to as “exhaust purification device”) 10 for an internal combustion engine according to a first embodiment.
  • This exhaust purification device 10 is a device for purifying NO x in exhaust gas, and is provided in an exhaust passage 11 of an internal combustion engine 1 such as a diesel engine mounted on a non-traveling vehicle such as a construction machine or an agricultural machine. ing. In such a non-traveling vehicle, there are restrictions on the arrangement space of the exhaust purification device 10, and the exhaust purification device 10 is often arranged in the engine room or close to the engine room.
  • the exhaust emission control device of the present invention includes those provided in internal combustion engines such as passenger cars and commercial vehicles.
  • the exhaust purification device 10 includes a reduction catalyst 13 interposed in the middle of the exhaust passage 11 and a reducing agent supply device 20 for supplying a liquid reducing agent into the exhaust passage 11 upstream of the reduction catalyst 13.
  • the reduction catalyst 13 is a catalyst having a function of promoting the reduction of NO x in the exhaust, adsorbs the reducing component generated from the liquid reducing agent, and selectively reduces the NO x in the exhaust flowing into the catalyst by the reducing component. It is a catalyst that reduces to The reducing agent supply device 20 uses a urea aqueous solution as a liquid reducing agent, and ammonia as a reducing component is generated when the urea aqueous solution is decomposed in the exhaust passage 11.
  • the reducing agent supply device 20 includes a storage tank 21 in which the liquid reducing agent is accommodated, a pump unit 22 for pumping the liquid reducing agent, and a reducing agent injection valve 25 for injecting the liquid reducing agent into the exhaust passage 11. And.
  • the pump unit 22 includes a pump 23 and a flow path switching valve 24.
  • the reducing agent injection valve 25, the pump 23, and the flow path switching valve 24 are controlled by an electronic control unit (Control Unit) 40.
  • the pump 23 and the storage tank 21 are connected by a first supply passage 31, and the pump 23 and the reducing agent injection valve 25 are connected by a second supply passage 33.
  • the second supply passage 33 is provided with a pressure sensor 27 for detecting the pressure in the second supply passage 33, that is, the pressure of the liquid reducing agent supplied to the reducing agent injection valve 25. Yes.
  • the pump 23 is connected to the first supply passage 31 and the second supply passage 33 via a flow path switching valve 24.
  • the end of the first supply passage 31 on the storage tank 21 side is located in the vicinity of the bottom surface of the storage tank 21 in order to allow the liquid reducing agent to be sucked up.
  • the flow path switching valve 24 has a direction in which the liquid reducing agent pumped by the pump 23 flows from the storage tank 21 side to the reducing agent injection valve 25 side (hereinafter referred to as “positive direction”), and a reducing agent injection valve. It has a function of switching from the 25 side to the direction of flowing to the storage tank 21 side (hereinafter referred to as “reverse direction”). That is, when the liquid reducing agent injection control is performed, the flow path switching valve 24 is not energized in order to supply the liquid reducing agent to the reducing agent injection valve 25 side. At this time, the liquid reducing agent flows in the positive direction. On the other hand, when the internal combustion engine 1 is stopped, the flow path switching valve 24 is energized when the liquid reducing agent in the reducing agent supply device 20 is collected in the storage tank 21. At this time, the liquid reducing agent flows in the reverse direction.
  • recover liquid reducing agents in the storage tank 21 is not restricted to the example which provides the flow-path switching valve 24.
  • the liquid reducing agent can be configured to be recoverable by using a pump 23 that can rotate in reverse.
  • a return passage 35 having the other end connected to the storage tank 21 is branched.
  • the end of the return passage 35 on the storage tank 21 side is connected to a gas phase portion in the storage tank 21 in order to prevent the back flow of the liquid reducing agent.
  • the position where the return passage 35 branches may be the outlet side 23 b of the pump 23, not the middle of the second supply passage 33.
  • a throttle portion 38 having a reduced flow path area is provided in the middle of the return passage 35 so that the pressure in the second supply passage 33 can be maintained.
  • the return passage 35 closer to the storage tank 21 than the throttling portion 38 is provided with a one-way valve 37 for preventing the liquid reducing agent from flowing from the storage tank 21 side to the second supply passage 33 side. Yes.
  • the one-way valve 37 may be omitted.
  • the pump 23 has its flow rate (output) controlled by energization control by the ECU 40 and pumps the liquid reducing agent.
  • the pump 23 also has a function as a means for collecting the liquid reducing agent in the storage tank 21.
  • the reducing agent injection valve 25 is controlled to be opened and closed by energization control by the ECU 40 in the operating state of the internal combustion engine 1, and injects a predetermined amount of liquid reducing agent into the exhaust passage 11.
  • the reducing agent injection valve 25 is an electromagnetic on / off valve that closes in a non-energized state and opens in an energized state.
  • the reducing agent injection valve 25 is held in a state in which the reducing agent injection valve 25 is opened when recovering the liquid reducing agent when the internal combustion engine 1 is stopped. Thereby, air (exhaust gas) is introduced into the second supply passage 33 through the nozzle hole of the reducing agent injection valve 25, and the liquid reducing agent is easily collected in the storage tank 21.
  • FIG. 2 shows an enlarged view of the portion indicated by X in FIG. 1 in detail.
  • FIG. 2 is a view for explaining in detail the cooling means of the exhaust emission control device 10 according to the first embodiment.
  • a branch pipe 12 is provided in an exhaust pipe main body 11 a constituting the exhaust passage 11.
  • the branch pipe 12 is connected to the exhaust pipe main body 11a at one end side, and a reducing agent injection valve 25 is fixed to the other end side.
  • the reducing agent injection valve 25 is held inside a housing 15 attached to the end of the branch pipe 12.
  • the housing 15 is provided with a cooling water passage (not shown) through which the cooling water of the internal combustion engine 1 can flow, and is supplied via the cooling water pipe 43 in the operating state of the internal combustion engine 1.
  • the reducing agent injection valve 25 is cooled by circulating the cooling water.
  • a cooling water pipe 41 capable of circulating cooling water is also wound around the branch pipe 12, and mainly from the exhaust pipe main body 11a via the branch pipe 12.
  • the exhaust heat transmitted to the reducing agent injection valve 25 can be reduced. If it is a cooling means using such a cooling water pipe 41, the cooling means using the cooling water of an internal combustion engine is easily realizable.
  • the cooling structure of the housing 15 through which the cooling water flows has a function of cooling the reducing agent injection valve 25 as a whole, while the cooling structure of the branch pipe 12 through which the cooling water flows also forms the reducing agent injection valve 25.
  • the amount of heat transferred itself is reduced, and in particular, it has a function of cooling the tip of the reducing agent injection valve 25.
  • the reducing agent injection valve 25 is cooled more efficiently, thermal damage to the reducing agent injection valve 25 can be reduced, and crystallization of the liquid reducing agent attached to the tip of the reducing agent injection valve 25 is prevented. Can do. Therefore, thermal damage and clogging of the reducing agent injection valve 25 can be prevented, and the injection control of the liquid reducing agent can be appropriately performed.
  • the cooling water passage of the internal combustion engine 1 is provided as the cooling means provided in the branch pipe 12, but the cooling means is not limited to this.
  • a liquid reducing agent supply passage or return passage may be provided around the branch pipe 12 to cool the branch pipe 12 using the liquid reducing agent as a refrigerant.
  • the configuration of the cooling means for reducing the exhaust heat transmitted to the reducing agent injection valve 25 is the same as that of the exhaust emission control device 10 according to the first embodiment. It is different from the case.
  • the configuration of the cooling means will be mainly described.
  • FIG. 3 shows an enlarged view of the mounting portion of the reducing agent injection valve 25 in detail.
  • FIG. 3 is a diagram for explaining in detail the cooling means of the exhaust gas purification apparatus according to the second embodiment. Also in the exhaust purification apparatus of the present embodiment, the reducing agent injection valve 25 is held and attached to the housing 16 having a cooling water passage (not shown).
  • a cooling water flow member 51 that constitutes a cooling means is interposed between the housing 15 that holds the reducing agent injection valve 25 and the branch pipe 12.
  • the cooling water circulation member 51 has a donut shape having an opening 51a at the center, and a cooling water flow passage 51b is formed inside. Yes.
  • the central opening 51a is provided with the housing 15 that holds the reducing agent injection valve 25, the tip of the reducing agent injection valve 25 being disposed, and the liquid reducing agent is injected into the branch pipe 12 through the opening 51a. It has come to be.
  • cooling water flow passage 51b opens to the outside at the inlet 51c and the outlet 51d.
  • cooling water pipes 53a and 53b are connected to the inlet 51c and the outlet 51d, respectively, and the cooling water flows through the cooling water flow passage 51b via the inlet 51c and the outlet 51d. It is like that.
  • the cooling structure of the housing 15 through which the cooling water flows has a function of cooling the reducing agent injection valve 25 that can be heated as a whole
  • the cooling structure having the cooling water circulation member 51 through which the cooling water flows also includes: The amount of heat transferred to the reducing agent injection valve 25 is reduced, and in particular, the tip of the reducing agent injection valve 25 is cooled. If it is a cooling means using such a cooling water distribution
  • the reducing agent injection valve 25 is cooled more efficiently, thermal damage to the reducing agent injection valve 25 can be reduced, and crystallization of the liquid reducing agent attached to the tip of the reducing agent injection valve 25 is prevented. Can do. Therefore, thermal damage and clogging of the reducing agent injection valve 25 can be prevented, and the injection control of the liquid reducing agent can be appropriately performed.
  • the cooling water flow member 51 in the second embodiment is configured as a separate member from the housing 15 and the branch pipe 12.
  • the second embodiment is different from the second embodiment in that a cooling water flow passage is provided in the mounting flange portion of the housing 15 in the branch pipe 12.
  • FIGS. 5A to 5D show the mounting flange portions 60a to 60d of the branch pipe 12 used in the cooling structure of the reducing agent injection valve of the exhaust gas purification apparatus according to the present embodiment.
  • a screw hole 61 for fixing the housing 15 that holds the reducing agent injection chamber 25 and the tip of the reducing agent injection valve 25 are disposed in each of the mounting flange portions 60a to 60d so that the liquid reducing agent can pass therethrough.
  • the opening 65 is formed along the thickness direction of the mounting flange portions 60a to 60d.
  • a cooling water flow passage 63 is provided in the mounting flange portions 60a to 60d so that the liquid reducing agent can circulate inside the mounting flange portions 60a to 60d.
  • the cooling water flow passage 63 is formed by a combination of long holes drilled by drills or the like from the sides of the mounting flange portions 60 a to 60 d, and unnecessary opening ends are closed by plugs 67.
  • the liquid reducing agent flows into the cooling water flow passage 63 from the inlet opening 63a, flows through the cooling water flow passage 63, and flows out from the outlet opening 63b.
  • a cooling water pipe (not shown) is connected to the inlet opening 63a and the outlet opening 63b so that the cooling water of the internal combustion engine 1 can be introduced.
  • the reducing agent injection valve 25 is cooled more efficiently, thermal damage to the reducing agent injection valve 25 can be reduced, and crystallization of the liquid reducing agent attached to the tip of the reducing agent injection valve 25 is prevented. Can do. Therefore, thermal damage and clogging of the reducing agent injection valve 25 can be prevented, and the injection control of the liquid reducing agent can be appropriately performed.
  • the cooling water flow passage 63 is provided in the mounting flange portions 60a to 60d integrally formed with the branch pipe 12, and the exhaust heat transmitted from the branch pipe 12 to the reducing agent injection valve 25. Therefore, the exhaust heat transmitted to the reducing agent injection valve 25 can be further easily reduced.

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

Abstract

An exhaust gas purifying device for an internal combustion engine is configured so as to efficiently reduce heat transmitted to a reducing agent spray valve. An exhaust gas purifying device is provided in the exhaust gas discharge passage of an internal combustion engine and purifies nitrogen oxide in exhaust gas using a liquid reducing agent. The exhaust gas purifying device comprises: a reducing catalyst which is provided in the exhaust gas discharge passage; and a reducing agent spray valve which, on the upstream side of the reducing catalyst, sprays the liquid reducing agent into the exhaust gas discharge passage. A branch pipe is provided to an exhaust pipe body, the reducing agent spray valve for spraying the liquid reducing agent is mounted to the branch pipe, and a cooling means for reducing the transmission of the heat of exhaust gas to the reducing agent spray valve is provided between the branch position where the branch pipe is branched from the exhaust gas pipe body and the position where the reducing agent spray valve is mounted.

Description

内燃機関の排気浄化装置Exhaust gas purification device for internal combustion engine
　本発明は、内燃機関の排気中の窒素酸化物を浄化するための排気浄化装置に関するものである。 The present invention relates to an exhaust purification device for purifying nitrogen oxides in exhaust gas of an internal combustion engine.
　ディーゼルエンジン等の内燃機関の排気には窒素酸化物（ＮＯX）が含まれている。このＮＯXを浄化する排気浄化装置の一つとして、内燃機関の排気通路中に配置される還元触媒と、還元触媒の上流側で尿素水溶液等の液体還元剤を噴射するための還元剤供給装置とを備えた排気浄化装置が知られている。この排気浄化装置は、還元触媒中で、排気中のＮＯXとアンモニアとを効率的に還元反応させ、ＮＯXを窒素や水等に分解するものとなっている。 Nitrogen oxides (NO x ) are contained in exhaust gas from internal combustion engines such as diesel engines. As one of the exhaust gas purification devices for purifying NO x , a reduction catalyst disposed in the exhaust passage of the internal combustion engine, and a reducing agent supply device for injecting a liquid reducing agent such as a urea aqueous solution upstream of the reduction catalyst There is known an exhaust emission control device including This exhaust gas purification apparatus efficiently reduces NO x and ammonia in exhaust gas in a reduction catalyst to decompose NO x into nitrogen, water, and the like.
　還元剤供給装置は、排気管に取り付けられた還元剤噴射弁を用いて液体還元剤を排気通路中に噴射するものとなっているが、還元剤噴射弁は電磁弁形式のものを使用することが一般的であって、排気管を介して伝達される排気熱から保護する必要がある。また、液体還元剤として尿素水溶液を用いる場合、還元剤噴射弁の先端に付着した尿素水溶液が加熱されて尿素が結晶化すると、還元剤噴射弁が詰まってしまい、液体還元剤を噴射することができなくなるおそれがある。そのため、自然放熱を促進する放熱フィンや、冷却水を流通可能な冷却水通路を設けたハウジング（冷却ジャケット）を用いて還元剤噴射弁を排気管に固定することが行われている（例えば、特許文献１を参照）。 The reducing agent supply device uses a reducing agent injection valve attached to the exhaust pipe to inject the liquid reducing agent into the exhaust passage, but the reducing agent injection valve must be of the solenoid valve type. However, it is necessary to protect from exhaust heat transmitted through the exhaust pipe. Further, when an aqueous urea solution is used as the liquid reducing agent, when the aqueous urea solution attached to the tip of the reducing agent injection valve is heated and urea crystallizes, the reducing agent injection valve is clogged and the liquid reducing agent is injected. There is a risk that it will not be possible. Therefore, the reducing agent injection valve is fixed to the exhaust pipe by using a heat radiation fin that promotes natural heat dissipation or a housing (cooling jacket) provided with a cooling water passage through which cooling water can flow (for example, (See Patent Document 1).
特開２００９－１３８６２７号公報JP 2009-138627 A
　しかしながら、上述した冷却機能は、内燃機関の運転中においては比較的効率的に働くものの、内燃機関の停止後にはその機能が停止し、残留する排気熱によって還元剤噴射弁が加熱されるおそれがある。
　また、近年では、建設機械や農業用機械等の非走行車両用内燃機関の排気系にも、上記のような排気浄化装置が用いられるようになっている。非走行車両の場合、乗用車や商用車等の走行車両とは異なり、配管や種々の装置の配置スペースが限られ、還元剤噴射弁も含めて排気浄化装置全体がエンジンルーム内に格納されることが多い。したがって、還元剤噴射弁がさらに熱の影響を受けやすくなることから、還元剤噴射弁への熱の影響を低減する必要性がより高くなる。 However, although the cooling function described above works relatively efficiently during the operation of the internal combustion engine, the function stops after the internal combustion engine stops, and the reducing agent injection valve may be heated by residual exhaust heat. is there.
In recent years, the exhaust purification device as described above is also used in the exhaust system of an internal combustion engine for non-traveling vehicles such as construction machinery and agricultural machinery. In the case of non-traveling vehicles, unlike traveling vehicles such as passenger cars and commercial vehicles, the space for piping and various devices is limited, and the entire exhaust emission control device including the reducing agent injection valve is stored in the engine room. There are many. Therefore, since the reducing agent injection valve becomes more susceptible to heat, the necessity for reducing the influence of heat on the reducing agent injection valve becomes higher.
　したがって、本発明は、内燃機関の排気浄化装置において、還元剤噴射弁へ伝達される熱を効率的に低減することを目的としている。 Therefore, an object of the present invention is to efficiently reduce the heat transmitted to the reducing agent injection valve in the exhaust gas purification apparatus for an internal combustion engine.
　本発明によれば、内燃機関の排気通路に備えられ、液体還元剤を用いて排気中の窒素酸化物を浄化する排気浄化装置であって、前記排気通路中に備えられた還元触媒と、前記還元触媒よりも上流側で前記液体還元剤を前記排気通路内に噴射するための還元剤噴射弁と、を備えた排気浄化装置において、排気管本体には分岐管が設けられ、前記液体還元剤を噴射するための還元剤噴射弁が前記分岐管に取り付けられ、前記分岐管と前記排気管本体との分岐位置から前記還元剤噴射弁の取り付け位置までの間に、前記還元剤噴射弁への排気熱の伝達を低減するための冷却手段を備えることを特徴とする内燃機関の排気浄化装置が提供され、上述した問題を解決することができる。 According to the present invention, there is provided an exhaust purification device that is provided in an exhaust passage of an internal combustion engine and purifies nitrogen oxides in exhaust using a liquid reducing agent, the reduction catalyst provided in the exhaust passage, And a reducing agent injection valve for injecting the liquid reducing agent into the exhaust passage on the upstream side of the reduction catalyst, wherein the exhaust pipe body is provided with a branch pipe, and the liquid reducing agent A reducing agent injection valve for injecting the reducing agent is attached to the branch pipe, and between the branch position of the branch pipe and the exhaust pipe main body and the attachment position of the reducing agent injection valve, An exhaust gas purification apparatus for an internal combustion engine characterized by including a cooling means for reducing the transmission of exhaust heat can solve the above-described problems.
　すなわち、本発明の内燃機関の排気浄化装置によれば、排気管本体から分岐する分岐管に還元剤噴射弁を取り付けるとともに、分岐管の分岐位置から還元剤噴射弁の取り付け位置までの間に冷却手段を設けることとしているために、還元剤噴射弁の取り付け位置よりも手前で、還元剤噴射弁に伝達される排気熱を低減することができる。したがって、還元剤噴射弁に伝達される熱量を低減することができ、還元剤噴射弁の熱損傷や液体還元剤の結晶化を防ぐことができる。 That is, according to the exhaust gas purification apparatus for an internal combustion engine of the present invention, the reducing agent injection valve is attached to the branch pipe branched from the exhaust pipe main body, and the cooling is performed from the branch position of the branch pipe to the attachment position of the reducing agent injection valve. Since the means is provided, it is possible to reduce the exhaust heat transmitted to the reducing agent injection valve before the attachment position of the reducing agent injection valve. Therefore, the amount of heat transmitted to the reducing agent injection valve can be reduced, and thermal damage to the reducing agent injection valve and crystallization of the liquid reducing agent can be prevented.
　また、本発明の内燃機関の排気浄化装置を構成するにあたり、前記冷却手段が、前記内燃機関の冷却水を流通可能な冷却水通路であることが好ましい。このように、内燃機関の冷却水を利用した冷却手段とすれば、他の冷却手段を用いることなく、例えば９０℃前後の温度に保たれる冷却水によって、排気熱を低減させることができる。 Further, in configuring the exhaust gas purification apparatus for an internal combustion engine of the present invention, it is preferable that the cooling means is a cooling water passage through which the cooling water of the internal combustion engine can flow. Thus, if it is set as the cooling means using the cooling water of an internal combustion engine, exhaust heat can be reduced by the cooling water maintained at the temperature of about 90 degreeC, for example, without using another cooling means.
　また、本発明の内燃機関の排気浄化装置を構成するにあたり、前記冷却水通路が、前記分岐管と前記還元剤噴射弁との間に介装される冷却水流通部材に設けられることが好ましい。このような冷却手段を用いることにより、排気浄化装置に対して容易に冷却手段を増設することが可能となる。 Further, in configuring the exhaust gas purification apparatus for an internal combustion engine of the present invention, it is preferable that the cooling water passage is provided in a cooling water circulation member interposed between the branch pipe and the reducing agent injection valve. By using such a cooling means, it becomes possible to easily add a cooling means to the exhaust emission control device.
　また、本発明の内燃機関の排気浄化装置を構成するにあたり、前記冷却水通路が、前記分岐管の端部に設けられ、前記還元剤噴射弁が取り付けられる取付フランジ部に設けられることが好ましい。このような冷却手段を備えることにより、分岐管を介して還元剤噴射弁に伝達される排気熱をより効率的に低減することができる。 Further, in configuring the exhaust gas purification apparatus for an internal combustion engine of the present invention, it is preferable that the cooling water passage is provided at an end portion of the branch pipe and is provided at an attachment flange portion to which the reducing agent injection valve is attached. By providing such a cooling means, the exhaust heat transmitted to the reducing agent injection valve via the branch pipe can be reduced more efficiently.
　また、本発明の内燃機関の排気浄化装置を構成するにあたり、前記冷却水通路が、前記分岐管の外周に巻き付けられた冷却水パイプであることが好ましい。このように冷却手段を構成することにより、内燃機関の冷却水を利用した冷却手段を容易に実現することができる。 Further, in configuring the exhaust gas purification apparatus for an internal combustion engine of the present invention, it is preferable that the cooling water passage is a cooling water pipe wound around the outer periphery of the branch pipe. By configuring the cooling means in this way, a cooling means using the cooling water of the internal combustion engine can be easily realized.
　また、本発明の内燃機関の排気浄化装置を構成するにあたり、前記還元剤噴射弁がハウジングに保持されて前記分岐管に取り付けられており、前記内燃機関の冷却水を前記ハウジング内にも流通可能とすることが好ましい。このように還元剤噴射弁を分岐管に取り付けるためのハウジングにも冷却水を流通可能とすることにより、還元剤噴射弁に伝達される排気熱をさらに低減することができ、還元剤噴射弁の熱損傷や液体還元剤の結晶化を防ぐことができる。 Further, in configuring the exhaust gas purification apparatus for an internal combustion engine of the present invention, the reducing agent injection valve is held by a housing and attached to the branch pipe, and the cooling water of the internal combustion engine can be circulated in the housing. It is preferable that Thus, by allowing the coolant to flow through the housing for attaching the reducing agent injection valve to the branch pipe, the exhaust heat transmitted to the reducing agent injection valve can be further reduced. Thermal damage and crystallization of the liquid reducing agent can be prevented.
本発明の実施の形態にかかる排気浄化装置の一例を示す全体図である。1 is an overall view showing an example of an exhaust purification device according to an embodiment of the present invention. 本発明の第１の実施の形態にかかる排気浄化装置の冷却手段を説明するために示す図である。It is a figure shown in order to demonstrate the cooling means of the exhaust gas purification apparatus concerning the 1st Embodiment of this invention. 本発明の第２の実施の形態にかかる排気浄化装置の冷却手段を説明するために示す図である。It is a figure shown in order to demonstrate the cooling means of the exhaust gas purification apparatus concerning the 2nd Embodiment of this invention. 冷却水流通部材を説明するために示す図である。It is a figure shown in order to demonstrate a cooling water distribution member. 本発明の第３の実施の形態にかかる排気浄化装置の冷却手段を説明するために示す図である。It is a figure shown in order to demonstrate the cooling means of the exhaust gas purification apparatus concerning the 3rd Embodiment of this invention.
　以下、適宜図面を参照して、本発明の内燃機関の排気浄化装置に関する実施の形態について具体的に説明する。
　なお、それぞれの図中、同じ符号を付してあるものについては、特に説明がない限り同一の部材を示しており、適宜説明が省略されている。 Hereinafter, embodiments of the exhaust gas purification apparatus for an internal combustion engine according to the present invention will be specifically described with reference to the drawings as appropriate.
In addition, in each figure, about the thing which attached | subjected the same code | symbol, the same member is shown unless there is particular description, and description is abbreviate | omitted suitably.
［第１の実施の形態］
１．排気浄化装置の全体構成
　図１は、第１の実施の形態にかかる内燃機関の排気浄化装置（以下、単に「排気浄化装置」という）１０の全体構成の一例を説明するために示す図である。
　この排気浄化装置１０は、排気中のＮＯXを浄化するための装置であり、建設機械や農業用機械等の非走行車両に搭載されたディーゼルエンジン等の内燃機関１の排気通路１１に備えられている。このような非走行車両用では、排気浄化装置１０の配置スペースに制約があり、エンジンルーム内、あるいは、エンジンルームに近接して排気浄化装置１０が配置される場合が多い。ただし、本発明の排気浄化装置は、乗用車や商用車等の内燃機関に備えられるものも含む。 [First Embodiment]
1. FIG. 1 is a diagram shown for explaining an example of the overall configuration of an exhaust purification device (hereinafter simply referred to as “exhaust purification device”) 10 for an internal combustion engine according to a first embodiment. .
This exhaust purification device 10 is a device for purifying NO x in exhaust gas, and is provided in an exhaust passage 11 of an internal combustion engine 1 such as a diesel engine mounted on a non-traveling vehicle such as a construction machine or an agricultural machine. ing. In such a non-traveling vehicle, there are restrictions on the arrangement space of the exhaust purification device 10, and the exhaust purification device 10 is often arranged in the engine room or close to the engine room. However, the exhaust emission control device of the present invention includes those provided in internal combustion engines such as passenger cars and commercial vehicles.
　排気浄化装置１０は、排気通路１１の途中に介装された還元触媒１３と、還元触媒１３よりも上流側の排気通路１１内に液体還元剤を供給するための還元剤供給装置２０とを備えている。還元触媒１３は、排気中のＮＯXの還元を促進する機能を有する触媒であり、液体還元剤から生成される還元成分を吸着するとともに、触媒に流れ込む排気中のＮＯXを還元成分によって選択的に還元する触媒である。還元剤供給装置２０は、液体還元剤として尿素水溶液が用いられるものであり、尿素水溶液が排気通路１１中で分解されることにより還元成分としてのアンモニアが生成されるようになっている。 The exhaust purification device 10 includes a reduction catalyst 13 interposed in the middle of the exhaust passage 11 and a reducing agent supply device 20 for supplying a liquid reducing agent into the exhaust passage 11 upstream of the reduction catalyst 13. ing. The reduction catalyst 13 is a catalyst having a function of promoting the reduction of NO x in the exhaust, adsorbs the reducing component generated from the liquid reducing agent, and selectively reduces the NO x in the exhaust flowing into the catalyst by the reducing component. It is a catalyst that reduces to The reducing agent supply device 20 uses a urea aqueous solution as a liquid reducing agent, and ammonia as a reducing component is generated when the urea aqueous solution is decomposed in the exhaust passage 11.
　還元剤供給装置２０は、液体還元剤が収容される貯蔵タンク２１と、液体還元剤を圧送するためのポンプユニット２２と、液体還元剤を排気通路１１内に噴射するための還元剤噴射弁２５とを備えている。ポンプユニット２２は、ポンプ２３及び流路切換弁２４を備えている。還元剤噴射弁２５、ポンプ２３、及び、流路切換弁２４は、電子制御装置（Ｃｏｎｔｒｏｌ　Ｕｎｉｔ）４０によって駆動制御が行われるものとなっている。 The reducing agent supply device 20 includes a storage tank 21 in which the liquid reducing agent is accommodated, a pump unit 22 for pumping the liquid reducing agent, and a reducing agent injection valve 25 for injecting the liquid reducing agent into the exhaust passage 11. And. The pump unit 22 includes a pump 23 and a flow path switching valve 24. The reducing agent injection valve 25, the pump 23, and the flow path switching valve 24 are controlled by an electronic control unit (Control Unit) 40.
　ポンプ２３と貯蔵タンク２１とは第１の供給通路３１によって接続され、ポンプ２３と還元剤噴射弁２５とは第２の供給通路３３によって接続されている。このうち、第２の供給通路３３には、第２の供給通路３３内の圧力、すなわち、還元剤噴射弁２５に供給される液体還元剤の圧力を検出するための圧力センサ２７が設けられている。ポンプ２３と、第１の供給通路３１及び第２の供給通路３３とは、流路切換弁２４を介して接続されている。第１の供給通路３１の貯蔵タンク２１側の端部は、液体還元剤の吸い上げを可能にするために、貯蔵タンク２１の底面近傍に位置している。 The pump 23 and the storage tank 21 are connected by a first supply passage 31, and the pump 23 and the reducing agent injection valve 25 are connected by a second supply passage 33. Among these, the second supply passage 33 is provided with a pressure sensor 27 for detecting the pressure in the second supply passage 33, that is, the pressure of the liquid reducing agent supplied to the reducing agent injection valve 25. Yes. The pump 23 is connected to the first supply passage 31 and the second supply passage 33 via a flow path switching valve 24. The end of the first supply passage 31 on the storage tank 21 side is located in the vicinity of the bottom surface of the storage tank 21 in order to allow the liquid reducing agent to be sucked up.
　流路切換弁２４は、ポンプ２３によって圧送される液体還元剤が流れる方向を、貯蔵タンク２１側から還元剤噴射弁２５側に流れる方向（以下「正方向」という。）と、還元剤噴射弁２５側から貯蔵タンク２１側に流れる方向（以下「逆方向」という。）とに切換える機能を有している。すなわち、液体還元剤の噴射制御を行う際には、液体還元剤を還元剤噴射弁２５側に供給するために、流路切換弁２４への通電は行われない。このとき、液体還元剤は正方向に流れる。一方、内燃機関１の停止時において、還元剤供給装置２０内の液体還元剤を貯蔵タンク２１に回収する場合には、流路切換弁２４に対して通電される。このとき、液体還元剤は逆方向に流れる。 The flow path switching valve 24 has a direction in which the liquid reducing agent pumped by the pump 23 flows from the storage tank 21 side to the reducing agent injection valve 25 side (hereinafter referred to as “positive direction”), and a reducing agent injection valve. It has a function of switching from the 25 side to the direction of flowing to the storage tank 21 side (hereinafter referred to as “reverse direction”). That is, when the liquid reducing agent injection control is performed, the flow path switching valve 24 is not energized in order to supply the liquid reducing agent to the reducing agent injection valve 25 side. At this time, the liquid reducing agent flows in the positive direction. On the other hand, when the internal combustion engine 1 is stopped, the flow path switching valve 24 is energized when the liquid reducing agent in the reducing agent supply device 20 is collected in the storage tank 21. At this time, the liquid reducing agent flows in the reverse direction.
　なお、液体還元剤を貯蔵タンク２１に回収可能とする構成は、流路切換弁２４を設ける例に限られない。例えば、逆回転可能なポンプ２３を用いることによって液体還元剤を回収可能に構成することもできる。 In addition, the structure which can collect | recover liquid reducing agents in the storage tank 21 is not restricted to the example which provides the flow-path switching valve 24. FIG. For example, the liquid reducing agent can be configured to be recoverable by using a pump 23 that can rotate in reverse.
　また、第２の供給通路３３の途中には、他端が貯蔵タンク２１に接続されたリターン通路３５が分岐して設けられている。リターン通路３５の貯蔵タンク２１側の端部は、液体還元剤の逆流を防ぐために、貯蔵タンク２１内の気相部分に接続されている。リターン通路３５が分岐する位置は、第２の供給通路３３の途中ではなく、ポンプ２３の出口側２３ｂとなっていてもよい。 In the middle of the second supply passage 33, a return passage 35 having the other end connected to the storage tank 21 is branched. The end of the return passage 35 on the storage tank 21 side is connected to a gas phase portion in the storage tank 21 in order to prevent the back flow of the liquid reducing agent. The position where the return passage 35 branches may be the outlet side 23 b of the pump 23, not the middle of the second supply passage 33.
　リターン通路３５の途中には、流路面積が小さくされた絞り部３８が設けられ、第２の供給通路３３内の圧力を保持できるようになっている。また、絞り部３８よりも貯蔵タンク２１側のリターン通路３５には、液体還元剤が貯蔵タンク２１側から第２の供給通路３３側に流れないようにするための一方向弁３７が設けられている。一方向弁３７は省略されていても構わない。 In the middle of the return passage 35, a throttle portion 38 having a reduced flow path area is provided so that the pressure in the second supply passage 33 can be maintained. The return passage 35 closer to the storage tank 21 than the throttling portion 38 is provided with a one-way valve 37 for preventing the liquid reducing agent from flowing from the storage tank 21 side to the second supply passage 33 side. Yes. The one-way valve 37 may be omitted.
　ポンプ２３は、ＥＣＵ４０による通電制御によって流量（出力）が制御されて、液体還元剤を圧送する。また、このポンプ２３が、液体還元剤を貯蔵タンク２１に回収するための手段としての機能も有する。 The pump 23 has its flow rate (output) controlled by energization control by the ECU 40 and pumps the liquid reducing agent. The pump 23 also has a function as a means for collecting the liquid reducing agent in the storage tank 21.
　還元剤噴射弁２５は、内燃機関１の運転状態において、ＥＣＵ４０による通電制御によって開閉制御が行われ、所定量の液体還元剤を排気通路１１内に噴射する。還元剤噴射弁２５は、非通電状態で閉弁し、通電状態で開弁する、電磁式のオンオフ弁が用いられている。一方、還元剤噴射弁２５は、内燃機関１の停止時において、液体還元剤を回収する際には、還元剤噴射弁２５を開弁した状態で保持される。これにより、還元剤噴射弁２５の噴孔を介して空気（排ガス）が第２の供給通路３３に導入され、液体還元剤が貯蔵タンク２１内に回収されやすくなる。 The reducing agent injection valve 25 is controlled to be opened and closed by energization control by the ECU 40 in the operating state of the internal combustion engine 1, and injects a predetermined amount of liquid reducing agent into the exhaust passage 11. The reducing agent injection valve 25 is an electromagnetic on / off valve that closes in a non-energized state and opens in an energized state. On the other hand, the reducing agent injection valve 25 is held in a state in which the reducing agent injection valve 25 is opened when recovering the liquid reducing agent when the internal combustion engine 1 is stopped. Thereby, air (exhaust gas) is introduced into the second supply passage 33 through the nozzle hole of the reducing agent injection valve 25, and the liquid reducing agent is easily collected in the storage tank 21.
２．還元剤噴射弁の冷却構造
　ここで、図２に、図１のＸで示す部分を拡大して詳細に示す。図２は、第１の実施の形態にかかる排気浄化装置１０の冷却手段を詳細に説明するために示す図である。
　本実施の形態にかかる排気浄化装置１０において、排気通路１１を構成する排気管本体１１ａには分岐管１２が設けられている。この分岐管１２は、その一端側において排気管本体１１ａに接続され、他端側に還元剤噴射弁２５が固定されている。還元剤噴射弁２５は、分岐管１２の端部に取り付けられたハウジング１５の内部に保持されている。 2. Here, FIG. 2 shows an enlarged view of the portion indicated by X in FIG. 1 in detail. FIG. 2 is a view for explaining in detail the cooling means of the exhaust emission control device 10 according to the first embodiment.
In the exhaust purification apparatus 10 according to the present embodiment, a branch pipe 12 is provided in an exhaust pipe main body 11 a constituting the exhaust passage 11. The branch pipe 12 is connected to the exhaust pipe main body 11a at one end side, and a reducing agent injection valve 25 is fixed to the other end side. The reducing agent injection valve 25 is held inside a housing 15 attached to the end of the branch pipe 12.
　このハウジング１５は、内燃機関１の冷却水を流通可能な冷却水通路（図示せず。）が内部に設けられたものであって、内燃機関１の運転状態において冷却水配管４３を介して供給される冷却水が循環することにより、還元剤噴射弁２５が冷却されるようになっている。 The housing 15 is provided with a cooling water passage (not shown) through which the cooling water of the internal combustion engine 1 can flow, and is supplied via the cooling water pipe 43 in the operating state of the internal combustion engine 1. The reducing agent injection valve 25 is cooled by circulating the cooling water.
　また、本実施の形態の排気浄化装置１０においては、分岐管１２の周囲にも、冷却水を流通可能な冷却水パイプ４１が巻き付けられており、主として、排気管本体１１ａから分岐管１２を介して還元剤噴射弁２５に伝達される排気熱を低減することができるようになっている。このような冷却水パイプ４１を利用した冷却手段であれば、内燃機関の冷却水を利用した冷却手段を容易に実現することができる。 Further, in the exhaust purification device 10 of the present embodiment, a cooling water pipe 41 capable of circulating cooling water is also wound around the branch pipe 12, and mainly from the exhaust pipe main body 11a via the branch pipe 12. Thus, the exhaust heat transmitted to the reducing agent injection valve 25 can be reduced. If it is a cooling means using such a cooling water pipe 41, the cooling means using the cooling water of an internal combustion engine is easily realizable.
　すなわち、冷却水が流通するハウジング１５の冷却構造は、還元剤噴射弁２５を全体的に冷却する機能を有する一方、同じく冷却水が流通する分岐管１２の冷却構造は、還元剤噴射弁２５に伝達される熱量自体を低減し、特に、還元剤噴射弁２５の先端部を冷却する機能を有している。 That is, the cooling structure of the housing 15 through which the cooling water flows has a function of cooling the reducing agent injection valve 25 as a whole, while the cooling structure of the branch pipe 12 through which the cooling water flows also forms the reducing agent injection valve 25. The amount of heat transferred itself is reduced, and in particular, it has a function of cooling the tip of the reducing agent injection valve 25.
　これにより、還元剤噴射弁２５がより効率的に冷却され、還元剤噴射弁２５の熱損傷を低減できるとともに、還元剤噴射弁２５の先端部に付着した液体還元剤の結晶化を防止することができる。したがって、還元剤噴射弁２５の熱損傷や詰まりを防止して、液体還元剤の噴射制御を適切に行うことができる。 Thereby, the reducing agent injection valve 25 is cooled more efficiently, thermal damage to the reducing agent injection valve 25 can be reduced, and crystallization of the liquid reducing agent attached to the tip of the reducing agent injection valve 25 is prevented. Can do. Therefore, thermal damage and clogging of the reducing agent injection valve 25 can be prevented, and the injection control of the liquid reducing agent can be appropriately performed.
　本実施の形態にかかる排気浄化装置１０では、分岐管１２に設ける冷却手段として、内燃機関１の冷却水通路を設けているが、冷却手段はこれに限られるものではない。例えば、液体還元剤の供給通路又はリターン通路を分岐管１２の周囲に配設して、液体還元剤を冷媒として分岐管１２の冷却を行うようにしてもよい。 In the exhaust purification device 10 according to the present embodiment, the cooling water passage of the internal combustion engine 1 is provided as the cooling means provided in the branch pipe 12, but the cooling means is not limited to this. For example, a liquid reducing agent supply passage or return passage may be provided around the branch pipe 12 to cool the branch pipe 12 using the liquid reducing agent as a refrigerant.
［第２の実施の形態］
　本発明の第２の実施の形態にかかる排気浄化装置は、還元剤噴射弁２５に伝達される排気熱を低減するための冷却手段の構成が第１の実施の形態にかかる排気浄化装置１０の場合と異なっている。以下、冷却手段の構成を中心に説明する。 [Second Embodiment]
In the exhaust emission control device according to the second embodiment of the present invention, the configuration of the cooling means for reducing the exhaust heat transmitted to the reducing agent injection valve 25 is the same as that of the exhaust emission control device 10 according to the first embodiment. It is different from the case. Hereinafter, the configuration of the cooling means will be mainly described.
　図３に、還元剤噴射弁２５の取り付け部分を拡大して詳細に示す。図３は、第２の実施の形態にかかる排気浄化装置の冷却手段を詳細に説明するために示す図である。本実施の形態の排気浄化装置においても、還元剤噴射弁２５は冷却水通路（図示せず。）を有するハウジング１６に保持されて取り付けられている。 FIG. 3 shows an enlarged view of the mounting portion of the reducing agent injection valve 25 in detail. FIG. 3 is a diagram for explaining in detail the cooling means of the exhaust gas purification apparatus according to the second embodiment. Also in the exhaust purification apparatus of the present embodiment, the reducing agent injection valve 25 is held and attached to the housing 16 having a cooling water passage (not shown).
　本実施の形態の排気浄化装置においては、還元剤噴射弁２５を保持するハウジング１５と分岐管１２との間に、冷却手段を構成する冷却水流通部材５１が介装されている。この冷却水流通部材５１は、図４（ａ）～（ｃ）に示すように、中央部に開口部５１ａを有するドーナツ型の形状を有しており、内部に冷却水流通路５１ｂが形成されている。中央の開口部５１ａは、還元剤噴射弁２５を保持するハウジング１５が取り付けられた状態で、還元剤噴射弁２５の先端部分が配置され、開口部５１ａを通じて液体還元剤が分岐管１２内に噴射されるようになっている。 In the exhaust gas purification apparatus of the present embodiment, a cooling water flow member 51 that constitutes a cooling means is interposed between the housing 15 that holds the reducing agent injection valve 25 and the branch pipe 12. As shown in FIGS. 4A to 4C, the cooling water circulation member 51 has a donut shape having an opening 51a at the center, and a cooling water flow passage 51b is formed inside. Yes. The central opening 51a is provided with the housing 15 that holds the reducing agent injection valve 25, the tip of the reducing agent injection valve 25 being disposed, and the liquid reducing agent is injected into the branch pipe 12 through the opening 51a. It has come to be.
　また、冷却水流通路５１ｂは、入口部５１ｃ及び出口部５１ｄにおいて外部に開口している。図３に示すように、この入口部５１ｃ及び出口部５１ｄには、それぞれ冷却水配管５３ａ、５３ｂが接続され、入口部５１ｃ及び出口部５１ｄを介して冷却水が冷却水流通路５１ｂ内を流通するようになっている。 Further, the cooling water flow passage 51b opens to the outside at the inlet 51c and the outlet 51d. As shown in FIG. 3, cooling water pipes 53a and 53b are connected to the inlet 51c and the outlet 51d, respectively, and the cooling water flows through the cooling water flow passage 51b via the inlet 51c and the outlet 51d. It is like that.
　すなわち、冷却水が流通するハウジング１５の冷却構造は、加熱され得る還元剤噴射弁２５を全体的に冷却する機能を有する一方、同じく冷却水が流通する冷却水流通部材５１を有する冷却構造は、還元剤噴射弁２５に伝達される熱量自体を低減し、特に、還元剤噴射弁２５の先端部を冷却する機能を有している。このような冷却水流通部材５１を用いた冷却手段であれば、既存の排気浄化装置に対して容易に冷却手段を増設することが可能となる。 That is, the cooling structure of the housing 15 through which the cooling water flows has a function of cooling the reducing agent injection valve 25 that can be heated as a whole, while the cooling structure having the cooling water circulation member 51 through which the cooling water flows also includes: The amount of heat transferred to the reducing agent injection valve 25 is reduced, and in particular, the tip of the reducing agent injection valve 25 is cooled. If it is a cooling means using such a cooling water distribution | circulation member 51, it will become possible to add a cooling means easily with respect to the existing exhaust gas purification apparatus.
　これにより、還元剤噴射弁２５がより効率的に冷却され、還元剤噴射弁２５の熱損傷を低減できるとともに、還元剤噴射弁２５の先端部に付着した液体還元剤の結晶化を防止することができる。したがって、還元剤噴射弁２５の熱損傷や詰まりを防止して、液体還元剤の噴射制御を適切に行うことができる。 Thereby, the reducing agent injection valve 25 is cooled more efficiently, thermal damage to the reducing agent injection valve 25 can be reduced, and crystallization of the liquid reducing agent attached to the tip of the reducing agent injection valve 25 is prevented. Can do. Therefore, thermal damage and clogging of the reducing agent injection valve 25 can be prevented, and the injection control of the liquid reducing agent can be appropriately performed.
［第３の実施の形態］
　本発明の第３の実施の形態にかかる排気浄化装置は、第２の実施の形態における冷却水流通部材５１がハウジング１５及び分岐管１２とは別体の部材として構成されているのに対して、分岐管１２におけるハウジング１５の取付フランジ部に冷却水流通路を設ける点で、第２の実施の形態と異なっている。 [Third Embodiment]
In the exhaust emission control device according to the third embodiment of the present invention, the cooling water flow member 51 in the second embodiment is configured as a separate member from the housing 15 and the branch pipe 12. The second embodiment is different from the second embodiment in that a cooling water flow passage is provided in the mounting flange portion of the housing 15 in the branch pipe 12.
　図５（ａ）～（ｄ）は、本実施の形態にかかる排気浄化装置の還元剤噴射弁の冷却構造に用いられる分岐管１２の取付フランジ部６０ａ～６０ｄを示している。それぞれの取付フランジ部６０ａ～６０ｄには、還元剤噴射べ２５を保持するハウジング１５を固定するためのねじ穴６１と、還元剤噴射弁２５の先端部が配置されて液体還元剤が通過可能にされた開口部６５とが、取付フランジ部６０ａ～６０ｄの厚さ方向に沿って形成されている。 FIGS. 5A to 5D show the mounting flange portions 60a to 60d of the branch pipe 12 used in the cooling structure of the reducing agent injection valve of the exhaust gas purification apparatus according to the present embodiment. A screw hole 61 for fixing the housing 15 that holds the reducing agent injection chamber 25 and the tip of the reducing agent injection valve 25 are disposed in each of the mounting flange portions 60a to 60d so that the liquid reducing agent can pass therethrough. The opening 65 is formed along the thickness direction of the mounting flange portions 60a to 60d.
　また、取付フランジ部６０ａ～６０ｄには、取付フランジ部６０ａ～６０ｄの内部を液体還元剤が循環可能なように冷却水流通路６３が設けられている。冷却水流通路６３は取付フランジ部６０ａ～６０ｄの側部からドリル等によって穿設された長穴の組み合わせによって形成されており、不要な開口端はプラグ６７によって塞がれている。図５（ａ）～（ｄ）にそれぞれ示すように、液体還元剤は入口開口６３ａから冷却水流通路６３内に流れ込み、冷却水流通路６３内を流れて出口開口６３ｂから流出する。入口開口６３ａ及び出口開口６３ｂには、図示しない冷却水パイプが接続されて、内燃機関１の冷却水が導入可能となっている。 In addition, a cooling water flow passage 63 is provided in the mounting flange portions 60a to 60d so that the liquid reducing agent can circulate inside the mounting flange portions 60a to 60d. The cooling water flow passage 63 is formed by a combination of long holes drilled by drills or the like from the sides of the mounting flange portions 60 a to 60 d, and unnecessary opening ends are closed by plugs 67. As shown in FIGS. 5A to 5D, the liquid reducing agent flows into the cooling water flow passage 63 from the inlet opening 63a, flows through the cooling water flow passage 63, and flows out from the outlet opening 63b. A cooling water pipe (not shown) is connected to the inlet opening 63a and the outlet opening 63b so that the cooling water of the internal combustion engine 1 can be introduced.
　これにより、還元剤噴射弁２５がより効率的に冷却され、還元剤噴射弁２５の熱損傷を低減できるとともに、還元剤噴射弁２５の先端部に付着した液体還元剤の結晶化を防止することができる。したがって、還元剤噴射弁２５の熱損傷や詰まりを防止して、液体還元剤の噴射制御を適切に行うことができる。特に、本実施の形態においては、分岐管１２と一体的に構成されている取付フランジ部６０ａ～６０ｄに冷却水流通路６３を設けて、分岐管１２から還元剤噴射弁２５に伝達される排気熱を取り除くこととしているために、還元剤噴射弁２５に伝達される排気熱をさらに容易に低減することができる。
  Thereby, the reducing agent injection valve 25 is cooled more efficiently, thermal damage to the reducing agent injection valve 25 can be reduced, and crystallization of the liquid reducing agent attached to the tip of the reducing agent injection valve 25 is prevented. Can do. Therefore, thermal damage and clogging of the reducing agent injection valve 25 can be prevented, and the injection control of the liquid reducing agent can be appropriately performed. In particular, in the present embodiment, the cooling water flow passage 63 is provided in the mounting flange portions 60a to 60d integrally formed with the branch pipe 12, and the exhaust heat transmitted from the branch pipe 12 to the reducing agent injection valve 25. Therefore, the exhaust heat transmitted to the reducing agent injection valve 25 can be further easily reduced.

Claims (6)

  1. 　内燃機関の排気通路に備えられ、液体還元剤を用いて排気中の窒素酸化物を浄化する排気浄化装置であって、前記排気通路中に備えられた還元触媒と、前記還元触媒よりも上流側で前記液体還元剤を前記排気通路内に噴射するための還元剤噴射弁と、を備えた排気浄化装置において、
    　排気管本体には分岐管が設けられ、前記液体還元剤を噴射するための還元剤噴射弁が前記分岐管に取り付けられ、
    　前記分岐管と前記排気管本体との分岐位置から前記還元剤噴射弁の取り付け位置までの間に、前記還元剤噴射弁への排気熱の伝達を低減するための冷却手段を備えることを特徴とする内燃機関の排気浄化装置。     An exhaust purification device that is provided in an exhaust passage of an internal combustion engine and purifies nitrogen oxides in exhaust using a liquid reducing agent, the reduction catalyst provided in the exhaust passage, and an upstream side of the reduction catalyst In the exhaust emission control device comprising a reducing agent injection valve for injecting the liquid reducing agent into the exhaust passage,
    A branch pipe is provided in the exhaust pipe main body, a reducing agent injection valve for injecting the liquid reducing agent is attached to the branch pipe,
    A cooling means for reducing the transmission of exhaust heat to the reducing agent injection valve is provided between a branch position of the branch pipe and the exhaust pipe main body and a mounting position of the reducing agent injection valve. An exhaust purification device for an internal combustion engine.
  2. 　前記冷却手段が、前記内燃機関の冷却水を流通可能な冷却水通路であ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 exhaust gas purification apparatus for an internal combustion engine according to claim 1, wherein the cooling means is a cooling water passage through which the cooling water of the internal combustion engine can flow.
  3. 　前記冷却水通路が、前記分岐管と前記還元剤噴射弁との間に介装される冷却水流通部材に設けられることを特徴とする請求項１又は２に記載の内燃機関の排気浄化装置。 The exhaust gas purification device for an internal combustion engine according to claim 1 or 2, wherein the cooling water passage is provided in a cooling water circulation member interposed between the branch pipe and the reducing agent injection valve.
  4. 　前記冷却水通路が、前記分岐管の端部に設けられ、前記還元剤噴射弁が取り付けられる取付フランジ部に設けられることを特徴とする請求項１又は２に記載の内燃機関の排気浄化装置。 3. The exhaust gas purification apparatus for an internal combustion engine according to claim 1, wherein the cooling water passage is provided at an end portion of the branch pipe and is provided in a mounting flange portion to which the reducing agent injection valve is attached.
  5. 　前記冷却水通路が、前記分岐管の外周に巻き付けられた冷却水パイプであることを特徴とする請求項１又は２に記載の内燃機関の排気浄化装置。 The exhaust gas purification apparatus for an internal combustion engine according to claim 1 or 2, wherein the cooling water passage is a cooling water pipe wound around an outer periphery of the branch pipe.
  6. 　前記還元剤噴射弁がハウジングに保持されて前記分岐管に取り付けられており、前記内燃機関の冷却水を前記ハウジング内にも流通可能としたことを特徴とする請求項１～５のいずれか一項に記載の内燃機関の排気浄化装置。 6. The reducing agent injection valve is held by a housing and attached to the branch pipe, so that the cooling water of the internal combustion engine can also flow through the housing. The exhaust gas purification apparatus for an internal combustion engine according to the item.
PCT/JP2014/053423 2013-03-27 2014-02-14 Exhaust gas purifying device for internal combustion engine WO2014156354A1 (en)

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JP2018204501A (en) * 2017-06-01 2018-12-27 株式会社デンソー Reductant injection device and adapter

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