WO2020262589A1 - Stirring device - Google Patents
Stirring device Download PDFInfo
- Publication number
- WO2020262589A1 WO2020262589A1 PCT/JP2020/025154 JP2020025154W WO2020262589A1 WO 2020262589 A1 WO2020262589 A1 WO 2020262589A1 JP 2020025154 W JP2020025154 W JP 2020025154W WO 2020262589 A1 WO2020262589 A1 WO 2020262589A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- urea water
- porous body
- exhaust gas
- injection valve
- radio wave
- Prior art date
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
-
- 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
Definitions
- the present disclosure relates to a stirrer, and more particularly to a stirrer that suppresses the precipitation of white products caused by urea water.
- the urea water stirred by the mixer does not diffuse. It adheres to the exhaust passage and the selective reduction catalyst device in the form of liquid or droplets. From the adhered urea water, a white product in which urea, melamine, cyanuric acid, biuret and the like are solidified is precipitated.
- the urea water is not hydrolyzed by that amount, and the amount of ammonia produced is reduced. Further, when the temperature of the exhaust gas rises and the precipitated white product is thermally decomposed, ammonia is produced. That is, the precipitation of this white product causes the amount of ammonia supplied to the selective reduction catalyst device to be too small or too large. As a result, there are problems that the reduction rate of nitrogen oxides in the selective reduction catalyst device decreases and the amount of ammonia passing through the selective reduction catalyst device increases.
- An object of the present disclosure is to provide a stirring device that suppresses the precipitation of white products caused by urea water.
- the stirrer of one aspect of the present disclosure that achieves the above object is the urea water injection valve arranged at the middle position of the exhaust passage through which the exhaust gas passes and the urea water injection valve arranged downstream of the flow of the exhaust gas.
- the stirrer has a porous body capable of adsorbing urea water on the surface facing the urea water injection valve. It is characterized by.
- the stirring portion has a porous body. This is advantageous in preventing the urea water from directly adhering to the exhaust passage and the selective reduction catalyst device, and the white product due to the urea water is deposited on the exhaust passage and the selective reduction catalyst device. It can be suppressed.
- FIG. 1 is a block diagram illustrating the stirring device of the embodiment.
- FIG. 2 is a perspective view of the stirring portion of FIG.
- FIG. 3 is a cross-sectional view shown by arrow III in FIG.
- FIG. 4 is a cross-sectional view shown by an arrow IV in FIG.
- FIG. 5 is a flow chart illustrating a heating method in the stirring device of the embodiment.
- the white arrow indicates the exhaust gas G1
- the X direction is the direction from the upstream side to the downstream side with respect to the flow of the exhaust gas G1
- the Y direction is the direction opposite to the X direction.
- the alternate long and short dash line in the figure indicates a signal line.
- the stirring device 10 of the present embodiment is arranged at an intermediate position of the exhaust passage 1 of an internal combustion engine mounted on a vehicle (not shown), and includes a stirring unit 11 and a dielectric heating unit 12. It is composed of.
- the exhaust passage 1 is composed of a cylindrical pipe, and is a passage through which exhaust gas G1 discharged from a plurality of cylinders of an internal combustion engine (not shown) passes, and extends from a diverse exhaust pipe communicating with the plurality of cylinders to an outlet to the outside of the vehicle. It is a passage.
- a urea water injection valve 2 and a selective reduction catalyst device 3 are arranged in order in the X direction at an intermediate position of the exhaust passage 1.
- the urea water injection valve 2 is a device that injects urea water toward the inside of the exhaust passage 1.
- the selective reduction catalyst device 3 is configured by supporting a catalyst such as zeolite on a porous ceramic carrier, and contains ammonia generated by hydrolyzing the injected urea water by the heat of the exhaust gas G1 as a reducing agent in the exhaust gas G1. It is a device that selectively reduces and purifies the nitrogen oxides produced.
- the position where the urea water injection valve 2 is arranged in the exhaust passage 1 is not limited to the downstream side with respect to the flow of the exhaust gas G1 with respect to the turbocharger (not shown), and may be the upstream side with respect to the exhaust gas pipe or the turbine of the turbocharger.
- the urea water injection valve 2 may be arranged on the upstream side of the charger, and the selective reduction catalyst device 3 may be arranged on the downstream side of the turbocharger.
- examples of the devices arranged on the upstream side of the urea water injection valve 2 and the downstream side of the selective reduction catalyst device 3 with respect to the flow of the exhaust gas G1 include an oxidation catalyst device, a filter device, and an ammonia adsorption catalyst device 4 (not shown). However, it is not particularly limited.
- the urea water injection valve 2 may be inserted into the exhaust passage 1 and may be arranged in a space formed by recessing a part of the inner wall of the exhaust passage 1.
- the stirring unit 11 is arranged inside the exhaust passage 1 between the urea water injection valve 2 and the selective reduction catalyst device 3, and the urea water injected from the urea water injection valve 2 collides with each other to stir the collided urea water. It is a device to do.
- the stirring unit 11 is preferably arranged in the vicinity of the urea water injection valve 2, and more preferably arranged at a position where the urea water droplets injected from the urea water injection valve 2 can collide.
- the injection portion where the urea water is injected is opened toward the lower right side in the drawing, and the urea water is injected in the direction from the upper left to the lower right in the drawing.
- the jetted urea water has droplets of various particle sizes, and the droplets of urea water having a small particle size have a small inertial force and flow along the flow of the exhaust gas G1, so that they are easily diffused into the exhaust gas G1 and ammonia. Is easily hydrolyzed.
- the droplets of urea water having a large particle size have a large inertial force, they are difficult to diffuse into the exhaust gas G1, and after being injected from the urea water injection valve 2, they go straight in a predetermined traveling direction.
- the position where the urea water droplets collide is on the path of the urea water droplets having a large particle size injected from the urea water injection valve 2.
- An axial fan motor is exemplified as the stirring unit 11, but the configuration is not limited to the axial fan motor as long as it can stir the urea water flowing through the exhaust passage 1.
- the stirring unit 11 may be a fixed straightening vane in which a large number of holes through which the exhaust gas can pass are formed in a plate facing the flow of the exhaust gas.
- the stirring unit 11 can improve the diffusivity of urea water by rotating like an axial fan motor, and can uniformly mix the volatilized urea.
- the stirring unit 11 of the present embodiment has a propeller fan 13 composed of a plurality of blades 14 and a porous body 15.
- the propeller fan 13 may have a plurality of blades 14 arranged at intervals in the pipe circumferential direction of the exhaust passage 1 so as to rotate in the pipe circumferential direction, and the hub or casing having a built-in drive motor may be used. The description will be omitted.
- the propeller fan 13 is preferably configured so that the exhaust gas G1 can be blown in the direction in which the exhaust gas G1 flows.
- the porous body 15 is arranged on each of the surfaces of the plurality of blades 14 facing the urea water injection valve 2.
- the surface of the blade 14 facing the urea water injection valve 2 is a surface facing the upstream side with respect to the flow of the exhaust gas G1 and a surface facing the Y direction.
- the porous body 15 is not limited to the blade 14, and may be arranged on a surface of the hub or casing facing the Y direction.
- the porous body 15 may be arranged on a part of a plurality of blades 14 of the propeller fan 13, but it is preferable that the porous body 15 is arranged on all of the plurality of blades 14.
- the porous body 15 is a member capable of adsorbing urea water, and it is desirable that the porous body 15 is a metal porous body capable of physically adsorbing urea water.
- the physical adsorption is a phenomenon in which droplets of urea water are adsorbed on the pores of the porous body 15 by van der Waals force, which is a phenomenon different from chemisorption.
- the porous body 15 may be made of a material that can withstand the temperature reached by the exhaust gas G1 passing through the stirring unit 11.
- the porous body 15 is preferably made of a metal having excellent heat resistance.
- the metal porous body those having a large number (innumerable) pores on the surface and inside due to sintering of metal powder, compression or lamination of metal cloth, or dissolution of gas in molten metal. Illustrated.
- the porous body 15 of the present embodiment is composed of a metal cloth 17 formed by entwining metal fibers 16.
- the porous body 15 may be composed of one metal cloth 17, but it is desirable that the porous body 15 is formed by laminating a plurality of metal cloths 17 in the direction in which the exhaust gas G1 flows.
- the porous body 15 can have pores of various sizes.
- Stainless steel is exemplified as the metal fiber 16.
- the metal cloth 17 are woven fabrics, knitted fabrics, and non-woven fabrics in which metal fibers 16 are entangled, but it is desirable that the metal cloth 17 is made of a non-woven fabric having non-uniform and complicated pores.
- the size of the pores of the porous body 15 becomes smaller in the X direction, and the porous body 15 formed by laminating the metal cloth 17 is a metal arranged on the downstream side. It is desirable that the size of the pores in the cloth 17 is smaller than the size of the pores in the metal cloth 17 arranged on the upstream side.
- the size of the pores of the porous body 15 is an average value of the sizes of a large number of pores existing in each of the layers.
- the minimum size of the pores of the porous body 15 is preferably set to about the particle size of droplets of urea water that are easily diffused into the exhaust gas G1 and easily hydrolyzed to ammonia, and the maximum size is It is preferable to set the particle size of the urea water droplets injected from the urea water injection valve 2 to about the maximum value.
- the size of the pores in the metal cloth 17 becomes smaller as the constituent metal fibers 16 become denser. Therefore, in the porous body 15 made of the metal cloth 17, it is desirable that the metal fibers 16 become denser in the X direction, and it is more desirable that the metal fibers 16 become denser in order in the X direction.
- the number of laminated metal cloths 17 in the porous body 15 is not particularly limited.
- the metal cloth 17 is preferably made of a non-woven fabric having non-uniform pores and complicated pores, but when a plurality of metal cloths 17 are laminated, not all the metal cloths 17 need to be made of the non-woven fabric, and the knitted fabric And a non-woven fabric may be used in combination.
- urea water When urea water is injected from the urea water injection valve 2 when the temperature of the exhaust gas G1 is low, the urea water having a small particle size diffuses and is hydrolyzed in the exhaust gas G1. On the other hand, urea water having a large particle size travels straight in the injection direction due to inertial force and collides with the stirring unit 11. The urea water that collides with the stirring unit 11 is adsorbed on the porous body 15. At this time, droplets of urea water having a large particle size are adsorbed on the metal cloth 17 having relatively large pores, and urea water having a small particle size passing through the metal cloth 17 is adsorbed on the metal cloth 17 having small pores. Will be done.
- the urea water droplets When the particle size of the urea water droplets is smaller than the pores of the porous body 15, the urea water droplets are separated from the porous body 15 and diffused into the exhaust gas G1 to be hydrolyzed. That is, the droplets of urea water having a particle size larger than the pores are not separated from the porous body 15 and the adsorption is maintained.
- the stirring unit 11 since the stirring unit 11 has the porous body 15, it is possible to adsorb liquid or droplet-shaped urea water that is difficult to hydrolyze. This is advantageous in preventing the urea water from directly adhering to the exhaust passage 1 and the selective reduction catalyst device 3, and white products caused by the urea water are formed in the exhaust passage 1 and the selective reduction catalyst device 3. Precipitation can be suppressed.
- the dielectric heating unit 12 is a radio wave absorber 18 arranged inside the exhaust passage 1 between the urea water injection valve 2 and the selective reduction catalyst device 3, and the exhaust passage 1. It is a device that has a radio wave oscillator 19 arranged outside and heats the stirring unit 11 by dielectric heating.
- the heating target of the dielectric heating unit 12 may be a part of the stirring unit 11, and the heating target of the dielectric heating unit 12 of the present embodiment is the porous body 15 of the stirring unit 11.
- the radio wave absorber 18 is arranged at the outer edge of the stirring unit 11 when viewed in the X direction.
- the outer edge portion of the stirring portion 11 is the outer edge portion of the portion for stirring urea water, and is not the casing but the tip end portion of the blade 14 of the propeller fan 13 in the present embodiment.
- the radio wave absorber 18 is arranged at each of the tip portions of the plurality of blades 14 of the propeller fan 13 so as to be able to transfer heat to the outer edge portion of the porous body 15 when viewed in the X direction.
- the radio wave absorber 18 does not have to be installed on the blade 14 in which the porous body 15 is not installed among the plurality of blades 14.
- radio wave absorber 18 examples include a resistance absorbing material, a dielectric absorbing material, and a magnetic absorbing material.
- the radio wave absorber 18 is preferably one that can withstand the temperature reached by the exhaust gas G1, and more preferably a resistant absorbing material or a magnetic absorbing material made of a metal material.
- the porous body 15 of the present embodiment has a portion of the entire surface of the blade 14 facing the urea water injection valve 2 excluding the tip. It shall cover.
- the radio wave oscillator 19 is a device that is arranged outside the exhaust passage 1 and oscillates radio waves toward the radio wave absorber 18 arranged inside the exhaust passage 1, and examples thereof include a magnetron, a klystron, and a traveling wave tube. To. It is desirable that a plurality of radio wave oscillators 19 are arranged outside the exhaust passage 1 at intervals when viewed in the X direction.
- the radio wave oscillated by the radio wave oscillator 19 is a microwave
- the dielectric heating unit 12 is preferably configured to heat at least a part of the stirring unit 11 by microwave heating.
- the radio wave oscillator 19 is electrically connected to a control device 21 electrically connected to the temperature acquisition device 20, and the control device 21 controls the oscillation of radio waves based on the temperature Tx acquired by the temperature acquisition device 20. ..
- the temperature acquisition device 20 is a temperature sensor that acquires the temperature Tx of the exhaust gas G1 passing through the selective reduction catalyst device 3. It is desirable that the temperature acquisition device 20 is arranged on the upstream side of the selective reduction catalyst device 3 with respect to the flow of the exhaust gas G1, and it is more desirable that the temperature acquisition device 20 is arranged in the vicinity of the urea water injection valve 2.
- the control device 21 is hardware composed of a central processing unit (CPU) that performs various information processing, an internal storage device that can read and write programs and information processing results used for performing various information processing, and various interfaces. Is.
- the control device 21 may be composed of a dosing control unit that controls the injection of urea water from the urea water injection valve 2.
- the control device 21 has a heating determination unit 22 and a heating control unit 23 as functional elements.
- Each functional element is stored as a program in the internal storage device, and is executed by the central processing unit in a timely manner.
- each functional element may be composed of a programmable controller (PLC) or an electric circuit in which each functions independently.
- PLC programmable controller
- the heating determination unit 22 inputs the temperature Tx of the exhaust gas G1 acquired by the temperature acquisition device 20 and determines whether or not the temperature Tx falls within the range of the preset lower limit value Ta or more and the upper limit value Tb or less. It is a functional element that outputs the determined result to the heating control unit 23.
- the heating control unit 23 is a functional element that controls the radio wave oscillator 19 to oscillate radio waves when the determination result of the heating determination unit 22 is input and the temperature Tx falls within a preset range.
- the range of the lower limit value Ta or more and the upper limit value Tb or less is a temperature range set in advance by experiments and tests, and is on the low temperature side of the temperature range in which urea water injection is permitted from the urea water injection valve 2.
- the temperature range in which the injection of urea water is permitted from the urea water injection valve 2 here means that the urea water can be hydrolyzed to ammonia, and the selective reduction catalyst device 3 uses ammonia as a reducing agent to use nitrogen oxides. It is a reducibly activated temperature range.
- the range on the low temperature side of the temperature range is a range in which the reaction rate of hydrolysis from urea water to ammonia is slower than the range on the high temperature side of the temperature range.
- the heating method of the stirring device 10 is a method that is repeatedly performed at predetermined cycles during the operation of an internal combustion engine (not shown).
- the predetermined cycle is a cycle in which the temperature acquisition device 20 acquires the temperature Tx.
- the passage of one cycle in the flow chart is indicated by "return”.
- the temperature acquisition device 20 acquires the temperature Tx (S110). Then, the heating determination unit 22 determines whether or not the acquired temperature Tx is equal to or higher than the lower limit value Ta (S120).
- the lower limit value Ta is set to the temperature at which the injection of urea water is started from the urea water injection valve 2, this step is not a comparison between the temperature Tx and the lower limit value Ta, but a step of determining the presence or absence of injection of urea water. May be.
- the heating determination unit 22 determines whether or not the acquired temperature Tx is equal to or lower than the upper limit value Tb (S130). On the other hand, when it is determined that the temperature Tx is lower than the lower limit value Ta (S120: NO), the process returns to the start.
- the heating control unit 23 issues a command to the radio wave oscillator 19, oscillates the radio wave (S140), and returns to the start.
- the heating control unit 23 stops the oscillation of the radio wave of the radio wave oscillator 19 (S150) and returns to the start.
- the radio wave absorber 18 absorbs the oscillated radio wave and generates heat. Then, the heat generated in the radio wave absorber 18 is transferred to the porous body 15 to heat the urea water adsorbed on the porous body 15. The heated urea water droplets volatilize, desorb from the porous body 15, diffuse into the exhaust gas G1, and are hydrolyzed.
- the dielectric heating unit 12 heats the stirring unit 11 by dielectric heating.
- Dielectric heating is superior to induction heating in terms of uniform heating, rapid heating, and selective heating. That is, the dielectric heating unit 12 is advantageous in avoiding the heating delay by rapidly heating the temperature Tx of the exhaust gas G1 which changes from moment to moment. Further, the dielectric heating unit 12 is advantageous for heating only the stirring unit 11 by selective heating.
- the stirring device 10 includes both the stirring unit 11 having the porous body 15 and the dielectric heating unit 12, but the stirring device 10 does not have the dielectric heating unit 12 and has the porous body 15.
- the stirring unit 11 may be composed of only the stirring unit 11, and the stirring device 10 may be composed of the stirring unit 11 and the dielectric heating unit 12 which do not have the porous body 15.
- the stirring device 10 can adsorb liquid or droplet urea water that could not be hydrolyzed. Further, the stirring device 10 can volatilize urea water that could not be volatilized at the temperature Tx of the exhaust gas G1 by dielectrically heating the stirring unit 11 by the dielectric heating unit 12.
- the stirring device 10 including both the stirring unit 11 having the porous body 15 and the dielectric heating unit 12 adsorbs the liquid or droplet-shaped urea water that could not be hydrolyzed by the porous body 15. Then, when the stirring device 10 cannot volatilize the adsorbed urea water at the temperature Tx of the exhaust gas G1, the adsorbed urea water can be volatilized by dielectrically heating the stirring unit 11 by the dielectric heating unit 12.
- the stirring device 10 including both the stirring unit 11 having the porous body 15 and the dielectric heating unit 12, the urea water is selectively used in the exhaust passage and as compared with the stirring device not provided with either one. It is advantageous to prevent direct adhesion to the reduction catalyst device, and it is possible to suppress precipitation of white products due to urea water in the exhaust passage and the selective reduction catalyst device.
- the amount of urea water that can be adsorbed by the porous body 15 of the stirrer 10 is set in advance by experiments and tests, and when urea water cannot be volatilized at the temperature Tx of the exhaust gas G1, urea is injected from the urea water injection valve 2.
- the amount of water jetted may be such that urea water does not scatter from the porous body 15.
- the porous body 15 may be installed at the bottom of the exhaust passage 1 on the upstream side of the selective reduction catalyst device 3 on the downstream side of the stirring unit 11 with respect to the flow of the exhaust gas G1.
- the bottom portion of the exhaust passage 1 here is a place where liquid or droplet urea water easily adheres.
- the place where the porous body 15 is installed in the exhaust passage 1 is preferably in the vicinity of the stirring unit 11. Further, it is desirable that the size of the pores of the porous body 15 installed in the exhaust passage 1 decreases from the center of the pipe toward the outside in the pipe radial direction.
- a radio wave absorber 18 that abuts on the porous body 15 installed in the exhaust passage 1 may be provided, and a radio wave oscillator 19 that oscillates a radio wave toward the radio wave absorber 18 may be provided.
- the radio wave absorber 18 is arranged at the tip of the blade 14, and the porous body 15 is removed from the entire surface of the blade 14 facing the urea water injection valve 2.
- the porous body 15 may be arranged on the surface of the radio wave absorber 18 facing the urea water injection valve 2.
- the stirring device according to the present disclosure is useful in that it can suppress the precipitation of white products caused by urea water in the exhaust passage and the selective reduction catalyst device.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Combustion & Propulsion (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Analytical Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Organic Chemistry (AREA)
- Biomedical Technology (AREA)
- Inorganic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Toxicology (AREA)
- Exhaust Gas After Treatment (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Abstract
A stirring device 10 according to the present invention is provided with a stirring unit 11 that is arranged between a urea water injection valve 2, which is arranged midway along an exhaust passage 1 where an exhaust gas G1 passes, and a selective reduction catalyst device 3. With respect to this stirring device 10, the stirring unit 11 comprises a porous body 15, which is capable of adsorbing the urea water, on a surface that faces the urea water injection valve 2.
Description
本開示は、攪拌装置に関し、より詳細には、尿素水に起因する白色生成物の析出を抑制する攪拌装置に関する。
The present disclosure relates to a stirrer, and more particularly to a stirrer that suppresses the precipitation of white products caused by urea water.
攪拌装置として尿素水噴射弁から噴射された尿素水の拡散を促進するミキサが提案されている(例えば、特許文献1参照)。
As a stirrer, a mixer that promotes the diffusion of urea water injected from a urea water injection valve has been proposed (see, for example, Patent Document 1).
ところで、尿素水噴射弁から噴射される尿素水の量が多かったり、排気通路を流れる排ガスの流量が少なかったり、排ガスの温度が低かったりすると、ミキサで攪拌された尿素水が拡散せずに、液状や液滴の状態で排気通路や選択的還元触媒装置に付着する。その付着した尿素水から、尿素、メラミン、シアヌル酸、ビウレットなどが固体化した白色生成物が析出する。
By the way, if the amount of urea water injected from the urea water injection valve is large, the flow rate of the exhaust gas flowing through the exhaust passage is small, or the temperature of the exhaust gas is low, the urea water stirred by the mixer does not diffuse. It adheres to the exhaust passage and the selective reduction catalyst device in the form of liquid or droplets. From the adhered urea water, a white product in which urea, melamine, cyanuric acid, biuret and the like are solidified is precipitated.
白色生成物が析出すると、その分、尿素水が加水分解されていないことになり、アンモニアの生成量が少なくなる。また、排気ガスの温度が上昇してその析出した白色生成物が熱分解するとアンモニアが生成される。つまり、この白色生成物が析出することで、選択的還元触媒装置に供給されるアンモニアの量が過少になったり、過多になったりする。この結果として、選択的還元触媒装置における窒素酸化物の還元率が低下したり、選択的還元触媒装置を通過するアンモニア量が増加したりする問題があった。
When the white product is precipitated, the urea water is not hydrolyzed by that amount, and the amount of ammonia produced is reduced. Further, when the temperature of the exhaust gas rises and the precipitated white product is thermally decomposed, ammonia is produced. That is, the precipitation of this white product causes the amount of ammonia supplied to the selective reduction catalyst device to be too small or too large. As a result, there are problems that the reduction rate of nitrogen oxides in the selective reduction catalyst device decreases and the amount of ammonia passing through the selective reduction catalyst device increases.
本開示の目的は、尿素水に起因する白色生成物の析出を抑制する攪拌装置を提供することである。
An object of the present disclosure is to provide a stirring device that suppresses the precipitation of white products caused by urea water.
上記の目的を達成する本開示の一態様の攪拌装置は、排ガスが通過する排気通路の中途位置に配置された尿素水噴射弁とこの尿素水噴射弁よりも排ガスの流れに関して下流側に配置された選択的還元触媒装置との間に配置された攪拌部を備える攪拌装置において、前記攪拌部はその前記尿素水噴射弁の側に向いた面に尿素水を吸着可能な多孔質体を有することを特徴とする。
The stirrer of one aspect of the present disclosure that achieves the above object is the urea water injection valve arranged at the middle position of the exhaust passage through which the exhaust gas passes and the urea water injection valve arranged downstream of the flow of the exhaust gas. In a stirrer having a stirrer arranged between the selective reduction catalyst device and the stirrer, the stirrer has a porous body capable of adsorbing urea water on the surface facing the urea water injection valve. It is characterized by.
本開示の一態様によれば、攪拌部が多孔質体を有することで加水分解できなかった液状あるいは液滴状の尿素水を吸着することができる。これにより、尿素水が排気通路や選択的還元触媒装置に直接付着することを防止するには有利になり、排気通路や選択的還元触媒装置に尿素水に起因する白色生成物が析出することを抑制することができる。
According to one aspect of the present disclosure, it is possible to adsorb liquid or droplet urea water that could not be hydrolyzed because the stirring portion has a porous body. This is advantageous in preventing the urea water from directly adhering to the exhaust passage and the selective reduction catalyst device, and the white product due to the urea water is deposited on the exhaust passage and the selective reduction catalyst device. It can be suppressed.
以下に、本開示における攪拌装置の実施形態について説明する。図中において、白抜き矢印が排ガスG1を示し、X方向をその排ガスG1の流れに関して上流側から下流側に向かう方向とし、Y方向をX方向の反対側の方向とする。また、図中の一点鎖線は信号線を示すものとする。
The embodiment of the stirring device in the present disclosure will be described below. In the figure, the white arrow indicates the exhaust gas G1, the X direction is the direction from the upstream side to the downstream side with respect to the flow of the exhaust gas G1, and the Y direction is the direction opposite to the X direction. The alternate long and short dash line in the figure indicates a signal line.
図1および図2に例示するように、本実施形態の攪拌装置10は図示しない車両に搭載された内燃機関の排気通路1の中途位置に配置され、攪拌部11と誘電加熱部12とを備えて構成される。
As illustrated in FIGS. 1 and 2, the stirring device 10 of the present embodiment is arranged at an intermediate position of the exhaust passage 1 of an internal combustion engine mounted on a vehicle (not shown), and includes a stirring unit 11 and a dielectric heating unit 12. It is composed of.
排気通路1は円筒管で構成されて、図示しない内燃機関の複数の気筒から排出される排ガスG1が通過する通路であり、複数の気筒に連通する排気多岐管から車両の外部への出口までの通路である。排気通路1の中途位置にはX方向に向かって順に尿素水噴射弁2と選択的還元触媒装置3とが配置される。尿素水噴射弁2は尿素水を排気通路1の内部に向かって噴射する装置である。選択的還元触媒装置3は多孔質セラミック担体にゼオライト等の触媒を担持して構成され、噴射された尿素水が排ガスG1の熱により加水分解されて生成されたアンモニアを還元剤として排ガスG1に含有される窒素酸化物を選択的に還元浄化する装置である。
The exhaust passage 1 is composed of a cylindrical pipe, and is a passage through which exhaust gas G1 discharged from a plurality of cylinders of an internal combustion engine (not shown) passes, and extends from a diverse exhaust pipe communicating with the plurality of cylinders to an outlet to the outside of the vehicle. It is a passage. A urea water injection valve 2 and a selective reduction catalyst device 3 are arranged in order in the X direction at an intermediate position of the exhaust passage 1. The urea water injection valve 2 is a device that injects urea water toward the inside of the exhaust passage 1. The selective reduction catalyst device 3 is configured by supporting a catalyst such as zeolite on a porous ceramic carrier, and contains ammonia generated by hydrolyzing the injected urea water by the heat of the exhaust gas G1 as a reducing agent in the exhaust gas G1. It is a device that selectively reduces and purifies the nitrogen oxides produced.
排気通路1における尿素水噴射弁2が配置される位置は図示しないターボチャージャよりも排ガスG1の流れに関して下流側に限定されずに、排気多岐管やターボチャージャのタービンよりも上流側でもよく、ターボチャージャの上流側に尿素水噴射弁2が配置され、ターボチャージャの下流側に選択的還元触媒装置3が配置されてもよい。また、排ガスG1の流れに関して尿素水噴射弁2の上流側や選択的還元触媒装置3の下流側に配置される装置としては、図示しない酸化触媒装置やフィルタ装置、アンモニア吸着触媒装置4が例示されるが特に限定されるものではない。加えて、尿素水噴射弁2は、排気通路1に挿通されていればよく、排気通路1の一部の内壁を窪ませて形成した空間に配置されてもよい。
The position where the urea water injection valve 2 is arranged in the exhaust passage 1 is not limited to the downstream side with respect to the flow of the exhaust gas G1 with respect to the turbocharger (not shown), and may be the upstream side with respect to the exhaust gas pipe or the turbine of the turbocharger. The urea water injection valve 2 may be arranged on the upstream side of the charger, and the selective reduction catalyst device 3 may be arranged on the downstream side of the turbocharger. Further, examples of the devices arranged on the upstream side of the urea water injection valve 2 and the downstream side of the selective reduction catalyst device 3 with respect to the flow of the exhaust gas G1 include an oxidation catalyst device, a filter device, and an ammonia adsorption catalyst device 4 (not shown). However, it is not particularly limited. In addition, the urea water injection valve 2 may be inserted into the exhaust passage 1 and may be arranged in a space formed by recessing a part of the inner wall of the exhaust passage 1.
攪拌部11は尿素水噴射弁2および選択的還元触媒装置3の間の排気通路1の内部に配置されて、尿素水噴射弁2から噴射された尿素水が衝突し、衝突した尿素水を攪拌する装置である。攪拌部11は、尿素水噴射弁2の近傍に配置されることが望ましく、尿素水噴射弁2から噴射された尿素水の液滴が衝突可能な位置に配置されることがより望ましい。
The stirring unit 11 is arranged inside the exhaust passage 1 between the urea water injection valve 2 and the selective reduction catalyst device 3, and the urea water injected from the urea water injection valve 2 collides with each other to stir the collided urea water. It is a device to do. The stirring unit 11 is preferably arranged in the vicinity of the urea water injection valve 2, and more preferably arranged at a position where the urea water droplets injected from the urea water injection valve 2 can collide.
本実施形態の尿素水噴射弁2は、尿素水が噴射される噴射部が図中において右下側に向かって開口しており、尿素水が図中の左上から右下に向う方向に噴射される。噴射された尿素水は様々な粒径の液滴があり、粒径が小さい尿素水の液滴は慣性力が小さくなり排ガスG1の流れに乗って流れるので、排ガスG1中に拡散され易く、アンモニアに加水分解され易い。一方、粒径が大きい尿素水の液滴は慣性力が大きいことから排ガスG1中に拡散され難く、尿素水噴射弁2から噴射された後に所定の進行方向に向かって直進する。本実施形態で、尿素水の液滴が衝突する位置とは、尿素水噴射弁2から噴射された粒径が大きな尿素水の液滴の進路上とする。
In the urea water injection valve 2 of the present embodiment, the injection portion where the urea water is injected is opened toward the lower right side in the drawing, and the urea water is injected in the direction from the upper left to the lower right in the drawing. Urea. The jetted urea water has droplets of various particle sizes, and the droplets of urea water having a small particle size have a small inertial force and flow along the flow of the exhaust gas G1, so that they are easily diffused into the exhaust gas G1 and ammonia. Is easily hydrolyzed. On the other hand, since the droplets of urea water having a large particle size have a large inertial force, they are difficult to diffuse into the exhaust gas G1, and after being injected from the urea water injection valve 2, they go straight in a predetermined traveling direction. In the present embodiment, the position where the urea water droplets collide is on the path of the urea water droplets having a large particle size injected from the urea water injection valve 2.
攪拌部11としては軸流ファンモータが例示されるが、排気通路1を流れる尿素水を攪拌可能な構成であればよく、その構成は軸流ファンモータに限定されるものではない。例えば、攪拌部11としては排ガスの流れに対向する板に排ガスが通過可能な多数の穴が形成された固定の整流板でもよい。但し、攪拌部11は、軸流ファンモータのように回転することで尿素水の拡散性を向上することができ、揮発した尿素を均一に混合することができる。
An axial fan motor is exemplified as the stirring unit 11, but the configuration is not limited to the axial fan motor as long as it can stir the urea water flowing through the exhaust passage 1. For example, the stirring unit 11 may be a fixed straightening vane in which a large number of holes through which the exhaust gas can pass are formed in a plate facing the flow of the exhaust gas. However, the stirring unit 11 can improve the diffusivity of urea water by rotating like an axial fan motor, and can uniformly mix the volatilized urea.
本実施形態の攪拌部11は、複数の羽根14から成るプロペラファン13と多孔質体15とを有する。プロペラファン13は排気通路1の管周方向に間隔を空けて配置された複数の羽根14がその管周方向に回転するものであればよく、駆動用のモータが内蔵されたハブやケーシングについてはその説明を省略する。プロペラファン13は排ガスG1の流れる方向に排ガスG1を送風可能に構成されることが好ましい。
The stirring unit 11 of the present embodiment has a propeller fan 13 composed of a plurality of blades 14 and a porous body 15. The propeller fan 13 may have a plurality of blades 14 arranged at intervals in the pipe circumferential direction of the exhaust passage 1 so as to rotate in the pipe circumferential direction, and the hub or casing having a built-in drive motor may be used. The description will be omitted. The propeller fan 13 is preferably configured so that the exhaust gas G1 can be blown in the direction in which the exhaust gas G1 flows.
多孔質体15は複数の羽根14の尿素水噴射弁2の側に向いた面のそれぞれに配置される。羽根14の尿素水噴射弁2の側に向いた面は排ガスG1の流れに関して上流側に向いた面であり、Y方向に向いた面である。なお、多孔質体15は羽根14に限らずにハブやケーシングのY方向に向いた面に配置されてもよい。多孔質体15はプロペラファン13の複数の羽根14の一部に配置されてもよいが、複数の羽根14の全てに配置されることが好ましい。
The porous body 15 is arranged on each of the surfaces of the plurality of blades 14 facing the urea water injection valve 2. The surface of the blade 14 facing the urea water injection valve 2 is a surface facing the upstream side with respect to the flow of the exhaust gas G1 and a surface facing the Y direction. The porous body 15 is not limited to the blade 14, and may be arranged on a surface of the hub or casing facing the Y direction. The porous body 15 may be arranged on a part of a plurality of blades 14 of the propeller fan 13, but it is preferable that the porous body 15 is arranged on all of the plurality of blades 14.
多孔質体15は尿素水を吸着可能な部材であり、尿素水を物理吸着可能な金属多孔質体であることが望ましい。物理吸着とは尿素水の液滴が多孔質体15の細孔にファンデルワールス力により吸着する現象であり、化学吸着とは異なる現象である。多孔質体15は攪拌部11を通過する排ガスG1が到達する温度に耐えられる材質であればよい。多孔質体15としては、耐熱性に優れる金属で構成されることが望ましい。また、金属多孔質体としては、金属粉体の焼結、金属布の圧縮や積層、あるいは、溶解金属へのガスの溶解により、表面および内部に多数(無数)の細孔が空いたものが例示される。
The porous body 15 is a member capable of adsorbing urea water, and it is desirable that the porous body 15 is a metal porous body capable of physically adsorbing urea water. The physical adsorption is a phenomenon in which droplets of urea water are adsorbed on the pores of the porous body 15 by van der Waals force, which is a phenomenon different from chemisorption. The porous body 15 may be made of a material that can withstand the temperature reached by the exhaust gas G1 passing through the stirring unit 11. The porous body 15 is preferably made of a metal having excellent heat resistance. In addition, as the metal porous body, those having a large number (innumerable) pores on the surface and inside due to sintering of metal powder, compression or lamination of metal cloth, or dissolution of gas in molten metal. Illustrated.
本実施形態の多孔質体15は金属繊維16が交絡して成る金属布17で構成される。多孔質体15は一枚の金属布17から構成されてもよいが、複数の金属布17が排ガスG1の流れる方向に積層して構成されることが望ましい。多孔質体15を複数の金属布17で構成することで、多孔質体15が様々な大きさの細孔を有することができる。
The porous body 15 of the present embodiment is composed of a metal cloth 17 formed by entwining metal fibers 16. The porous body 15 may be composed of one metal cloth 17, but it is desirable that the porous body 15 is formed by laminating a plurality of metal cloths 17 in the direction in which the exhaust gas G1 flows. By forming the porous body 15 with a plurality of metal cloths 17, the porous body 15 can have pores of various sizes.
金属繊維16としてはステンレス鋼が例示される。金属布17は金属繊維16が交絡して成る織物、編物、および、不織布が例示されるが、細孔が不均一で且つ複雑になる不織布で構成されることが望ましい。
Stainless steel is exemplified as the metal fiber 16. Examples of the metal cloth 17 are woven fabrics, knitted fabrics, and non-woven fabrics in which metal fibers 16 are entangled, but it is desirable that the metal cloth 17 is made of a non-woven fabric having non-uniform and complicated pores.
図3に例示するように、多孔質体15の細孔の大きさはX方向に向かって小さくなることが望ましく、金属布17が積層して成る多孔質体15は下流側に配置された金属布17における細孔の大きさが上流側に配置された金属布17における細孔の大きさよりも小さいことが望ましい。本開示で多孔質体15の細孔の大きさは各層のそれぞれに存在する多数の細孔の大きさの平均値とする。多孔質体15の細孔の大きさの最小は、排ガスG1中に拡散され易く、アンモニアに加水分解され易い尿素水の液滴の粒径程度に設定されることが好ましく、大きさの最大は尿素水噴射弁2から噴射される尿素水の液滴の粒径の最大値程度に設定されることが好ましい。
As illustrated in FIG. 3, it is desirable that the size of the pores of the porous body 15 becomes smaller in the X direction, and the porous body 15 formed by laminating the metal cloth 17 is a metal arranged on the downstream side. It is desirable that the size of the pores in the cloth 17 is smaller than the size of the pores in the metal cloth 17 arranged on the upstream side. In the present disclosure, the size of the pores of the porous body 15 is an average value of the sizes of a large number of pores existing in each of the layers. The minimum size of the pores of the porous body 15 is preferably set to about the particle size of droplets of urea water that are easily diffused into the exhaust gas G1 and easily hydrolyzed to ammonia, and the maximum size is It is preferable to set the particle size of the urea water droplets injected from the urea water injection valve 2 to about the maximum value.
金属布17における細孔の大きさは構成する金属繊維16が密になることで小さくなる。よって、金属布17で構成される多孔質体15はX方向に向かって金属繊維16が密になることが望ましく、X方向に向かって順々に金属繊維16が密になることがより望ましい。
The size of the pores in the metal cloth 17 becomes smaller as the constituent metal fibers 16 become denser. Therefore, in the porous body 15 made of the metal cloth 17, it is desirable that the metal fibers 16 become denser in the X direction, and it is more desirable that the metal fibers 16 become denser in order in the X direction.
多孔質体15における金属布17の積層数は特に限定されるものではない。金属布17は細孔が不均一で且つ複雑になる不織布で構成されることが好ましいが、複数の金属布17が積層する場合に全ての金属布17が不織布で構成されなくてもよく、編物と不織布との組み合わせでもよい。
The number of laminated metal cloths 17 in the porous body 15 is not particularly limited. The metal cloth 17 is preferably made of a non-woven fabric having non-uniform pores and complicated pores, but when a plurality of metal cloths 17 are laminated, not all the metal cloths 17 need to be made of the non-woven fabric, and the knitted fabric And a non-woven fabric may be used in combination.
排ガスG1の温度が低い状況で尿素水噴射弁2から尿素水が噴射されると、粒径の小さい尿素水は拡散し、排ガスG1中で加水分解される。一方、粒径の大きい尿素水は慣性力により噴射方向に直進し、攪拌部11に衝突する。攪拌部11に衝突した尿素水は多孔質体15に吸着される。このとき、粒径が大きい尿素水の液滴は細孔が比較的に大きい金属布17に吸着され、その金属布17を通り抜けた粒径が小さい尿素水は細孔が小さい金属布17に吸着される。
When urea water is injected from the urea water injection valve 2 when the temperature of the exhaust gas G1 is low, the urea water having a small particle size diffuses and is hydrolyzed in the exhaust gas G1. On the other hand, urea water having a large particle size travels straight in the injection direction due to inertial force and collides with the stirring unit 11. The urea water that collides with the stirring unit 11 is adsorbed on the porous body 15. At this time, droplets of urea water having a large particle size are adsorbed on the metal cloth 17 having relatively large pores, and urea water having a small particle size passing through the metal cloth 17 is adsorbed on the metal cloth 17 having small pores. Will be done.
尿素水の液滴の粒径が多孔質体15の細孔よりも小さくなると、尿素水の液滴は多孔質体15から脱離して、排ガスG1に拡散されて加水分解される。つまり、その細孔よりも粒径が大きい尿素水の液滴は多孔質体15から脱離されずに吸着が維持される。
When the particle size of the urea water droplets is smaller than the pores of the porous body 15, the urea water droplets are separated from the porous body 15 and diffused into the exhaust gas G1 to be hydrolyzed. That is, the droplets of urea water having a particle size larger than the pores are not separated from the porous body 15 and the adsorption is maintained.
このように、攪拌部11が多孔質体15を有することで加水分解し難い液状あるいは液滴状の尿素水を吸着することができる。これにより、尿素水が排気通路1や選択的還元触媒装置3に直接付着することを防止するには有利になり、排気通路1や選択的還元触媒装置3に尿素水に起因する白色生成物が析出することを抑制することができる。
In this way, since the stirring unit 11 has the porous body 15, it is possible to adsorb liquid or droplet-shaped urea water that is difficult to hydrolyze. This is advantageous in preventing the urea water from directly adhering to the exhaust passage 1 and the selective reduction catalyst device 3, and white products caused by the urea water are formed in the exhaust passage 1 and the selective reduction catalyst device 3. Precipitation can be suppressed.
図1および図4に例示するように、誘電加熱部12は尿素水噴射弁2および選択的還元触媒装置3の間の排気通路1の内部に配置された電波吸収体18と、排気通路1の外部に配置された電波発振器19とを有し、攪拌部11を誘電加熱により加熱する装置である。誘電加熱部12の加熱対象は攪拌部11の一部であってもよく、本実施形態の誘電加熱部12は加熱対象が攪拌部11の多孔質体15である。
As illustrated in FIGS. 1 and 4, the dielectric heating unit 12 is a radio wave absorber 18 arranged inside the exhaust passage 1 between the urea water injection valve 2 and the selective reduction catalyst device 3, and the exhaust passage 1. It is a device that has a radio wave oscillator 19 arranged outside and heats the stirring unit 11 by dielectric heating. The heating target of the dielectric heating unit 12 may be a part of the stirring unit 11, and the heating target of the dielectric heating unit 12 of the present embodiment is the porous body 15 of the stirring unit 11.
電波吸収体18はX方向に見て攪拌部11の外縁部に配置される。本開示で、攪拌部11の外縁部とは、尿素水を攪拌する部位の外縁部であり、本実施形態においてケーシングでは無く、プロペラファン13の羽根14の先端部とする。
The radio wave absorber 18 is arranged at the outer edge of the stirring unit 11 when viewed in the X direction. In the present disclosure, the outer edge portion of the stirring portion 11 is the outer edge portion of the portion for stirring urea water, and is not the casing but the tip end portion of the blade 14 of the propeller fan 13 in the present embodiment.
電波吸収体18はプロペラファン13の複数の羽根14の先端部のそれぞれに配置されて、X方向に見て多孔質体15の外縁部に伝熱可能に当接することが望ましい。なお、電波吸収体18は、複数の羽根14のうちの多孔質体15が設置されていない羽根14には設置しなくてもよい。
It is desirable that the radio wave absorber 18 is arranged at each of the tip portions of the plurality of blades 14 of the propeller fan 13 so as to be able to transfer heat to the outer edge portion of the porous body 15 when viewed in the X direction. The radio wave absorber 18 does not have to be installed on the blade 14 in which the porous body 15 is not installed among the plurality of blades 14.
電波吸収体18は、抵抗性吸収材料、誘電性吸収材料、および、磁性吸収材料が例示される。電波吸収体18は、排ガスG1が到達する温度に耐えられるものが望ましく、金属材料から成る抵抗性吸収材料や磁性吸収材料がより望ましい。
Examples of the radio wave absorber 18 include a resistance absorbing material, a dielectric absorbing material, and a magnetic absorbing material. The radio wave absorber 18 is preferably one that can withstand the temperature reached by the exhaust gas G1, and more preferably a resistant absorbing material or a magnetic absorbing material made of a metal material.
電波吸収体18を羽根14の先端部に配置するため、本実施形態の多孔質体15は羽根14の尿素水噴射弁2の側に向いた面の全域のうちの先端部を除いた部位を覆うものとする。
Since the radio wave absorber 18 is arranged at the tip of the blade 14, the porous body 15 of the present embodiment has a portion of the entire surface of the blade 14 facing the urea water injection valve 2 excluding the tip. It shall cover.
電波発振器19は排気通路1の外側に配置されて、排気通路1の内部に配置された電波吸収体18に向かって電波を発振する装置であり、マグネトロン、クライストロン、および、進行波管が例示される。電波発振器19はX方向に見て排気通路1の外側に間隔を空けて複数配置されることが望ましい。
The radio wave oscillator 19 is a device that is arranged outside the exhaust passage 1 and oscillates radio waves toward the radio wave absorber 18 arranged inside the exhaust passage 1, and examples thereof include a magnetron, a klystron, and a traveling wave tube. To. It is desirable that a plurality of radio wave oscillators 19 are arranged outside the exhaust passage 1 at intervals when viewed in the X direction.
電波発振器19が発振する電波はマイクロ波であることが望ましく、誘電加熱部12はマイクロ波加熱により攪拌部11の少なくとも一部を加熱する構成であることが望ましい。
It is desirable that the radio wave oscillated by the radio wave oscillator 19 is a microwave, and the dielectric heating unit 12 is preferably configured to heat at least a part of the stirring unit 11 by microwave heating.
電波発振器19は温度取得装置20と電気的に接続された制御装置21に電気的に接続されて、温度取得装置20の取得した温度Txに基づいて、制御装置21により電波の発振が制御される。
The radio wave oscillator 19 is electrically connected to a control device 21 electrically connected to the temperature acquisition device 20, and the control device 21 controls the oscillation of radio waves based on the temperature Tx acquired by the temperature acquisition device 20. ..
温度取得装置20は選択的還元触媒装置3を通過する排ガスG1の温度Txを取得する温度センサである。温度取得装置20は、排ガスG1の流れに関して選択的還元触媒装置3よりも上流側に配置されることが望ましく、尿素水噴射弁2の近傍に配置されることがより望ましい。
The temperature acquisition device 20 is a temperature sensor that acquires the temperature Tx of the exhaust gas G1 passing through the selective reduction catalyst device 3. It is desirable that the temperature acquisition device 20 is arranged on the upstream side of the selective reduction catalyst device 3 with respect to the flow of the exhaust gas G1, and it is more desirable that the temperature acquisition device 20 is arranged in the vicinity of the urea water injection valve 2.
制御装置21は、各種情報処理を行う中央演算装置(CPU)、その各種情報処理を行うために用いられるプログラムや情報処理結果を読み書き可能な内部記憶装置、及び各種インターフェースなどから構成されるハードウェアである。制御装置21は、尿素水噴射弁2の尿素水の噴射を制御するドージングコントロールユニットで構成されてもよい。
The control device 21 is hardware composed of a central processing unit (CPU) that performs various information processing, an internal storage device that can read and write programs and information processing results used for performing various information processing, and various interfaces. Is. The control device 21 may be composed of a dosing control unit that controls the injection of urea water from the urea water injection valve 2.
制御装置21は、機能要素として加熱判定部22、および、加熱制御部23を有する。各機能要素は、プログラムとして内部記憶装置に記憶されていて、適時、中央演算装置により実行されている。なお、各機能要素としては、プログラムの他にそれぞれが独立して機能するプログラマブルコントローラ(PLC)や電気回路で構成されてもよい。
The control device 21 has a heating determination unit 22 and a heating control unit 23 as functional elements. Each functional element is stored as a program in the internal storage device, and is executed by the central processing unit in a timely manner. In addition to the program, each functional element may be composed of a programmable controller (PLC) or an electric circuit in which each functions independently.
加熱判定部22は温度取得装置20が取得した排ガスG1の温度Txが入力されて、その温度Txが予め設定された下限値Ta以上、且つ、上限値Tb以下の範囲に収まるか否かを判定し、判定した結果を加熱制御部23に出力する機能要素である。
The heating determination unit 22 inputs the temperature Tx of the exhaust gas G1 acquired by the temperature acquisition device 20 and determines whether or not the temperature Tx falls within the range of the preset lower limit value Ta or more and the upper limit value Tb or less. It is a functional element that outputs the determined result to the heating control unit 23.
加熱制御部23は加熱判定部22の判定結果が入力されて、温度Txが予め設定された範囲に収まるという判定結果の場合に、電波発振器19に電波を発振させる制御を行う機能要素である。
The heating control unit 23 is a functional element that controls the radio wave oscillator 19 to oscillate radio waves when the determination result of the heating determination unit 22 is input and the temperature Tx falls within a preset range.
下限値Ta以上、且つ、上限値Tb以下の範囲は、予め実験や試験により設定された温度範囲であり、尿素水噴射弁2から尿素水の噴射が許可される温度範囲のうちの低温側の範囲に設定される。ここでいう尿素水噴射弁2から尿素水の噴射が許可される温度範囲とは、尿素水がアンモニアに加水分解可能で、且つ、選択的還元触媒装置3がアンモニアを還元剤として窒素酸化物を還元可能に活性化した温度範囲である。また、その温度範囲のうちの低温側の範囲とは、その温度範囲の高温側の範囲に比して尿素水からアンモニアへの加水分解の反応速度が遅い範囲である。
The range of the lower limit value Ta or more and the upper limit value Tb or less is a temperature range set in advance by experiments and tests, and is on the low temperature side of the temperature range in which urea water injection is permitted from the urea water injection valve 2. Set to range. The temperature range in which the injection of urea water is permitted from the urea water injection valve 2 here means that the urea water can be hydrolyzed to ammonia, and the selective reduction catalyst device 3 uses ammonia as a reducing agent to use nitrogen oxides. It is a reducibly activated temperature range. Further, the range on the low temperature side of the temperature range is a range in which the reaction rate of hydrolysis from urea water to ammonia is slower than the range on the high temperature side of the temperature range.
図5に例示するように、攪拌装置10の加熱方法は、図示しない内燃機関の運転中に所定の周期ごとに繰り返し行われる方法である。本開示で、所定の周期とは温度取得装置20が温度Txを取得する周期とする。なお、フロー図における一周期の経過は「リターン」で示す。
As illustrated in FIG. 5, the heating method of the stirring device 10 is a method that is repeatedly performed at predetermined cycles during the operation of an internal combustion engine (not shown). In the present disclosure, the predetermined cycle is a cycle in which the temperature acquisition device 20 acquires the temperature Tx. The passage of one cycle in the flow chart is indicated by "return".
内燃機関の運転が開始されると、温度取得装置20が温度Txを取得する(S110)。ついで、加熱判定部22が、取得した温度Txが下限値Ta以上か否かを判定する(S120)。下限値Taが尿素水噴射弁2から尿素水の噴射を開始する温度に設定されている場合にこのステップは温度Txと下限値Taとの比較では無く、尿素水の噴射の有無を判定するステップとしてもよい。
When the operation of the internal combustion engine is started, the temperature acquisition device 20 acquires the temperature Tx (S110). Then, the heating determination unit 22 determines whether or not the acquired temperature Tx is equal to or higher than the lower limit value Ta (S120). When the lower limit value Ta is set to the temperature at which the injection of urea water is started from the urea water injection valve 2, this step is not a comparison between the temperature Tx and the lower limit value Ta, but a step of determining the presence or absence of injection of urea water. May be.
ついで、温度Txが下限値Ta以上と判定した場合に(S120:YES)、加熱判定部22が、取得した温度Txが上限値Tb以下か否かを判定する(S130)。一方、温度Txが下限値Taを下回ると判定した場合に(S120:NO)、スタートへ戻る。
Then, when it is determined that the temperature Tx is equal to or higher than the lower limit value Ta (S120: YES), the heating determination unit 22 determines whether or not the acquired temperature Tx is equal to or lower than the upper limit value Tb (S130). On the other hand, when it is determined that the temperature Tx is lower than the lower limit value Ta (S120: NO), the process returns to the start.
ついで、温度Txが上限値Tb以下と判定した場合に(S130:YES)、加熱制御部23が、電波発振器19に指令を出し、電波を発振させて(S140)、スタートへ戻る。一方、温度Txが上限値Tbを上回ると判定した場合に(S130:NO)、加熱制御部23が、電波発振器19の電波の発振を停止させて(S150)、スタートへ戻る。
Then, when it is determined that the temperature Tx is equal to or less than the upper limit value Tb (S130: YES), the heating control unit 23 issues a command to the radio wave oscillator 19, oscillates the radio wave (S140), and returns to the start. On the other hand, when it is determined that the temperature Tx exceeds the upper limit value Tb (S130: NO), the heating control unit 23 stops the oscillation of the radio wave of the radio wave oscillator 19 (S150) and returns to the start.
電波発振器19が電波を発振すると、電波吸収体18が発振された電波を吸収して発熱する。ついで、電波吸収体18で生じた熱が多孔質体15に伝熱して、多孔質体15に吸着された尿素水を加熱する。加熱された尿素水の液滴は揮発して多孔質体15から脱離して、排ガスG1に拡散されて加水分解される。
When the radio wave oscillator 19 oscillates a radio wave, the radio wave absorber 18 absorbs the oscillated radio wave and generates heat. Then, the heat generated in the radio wave absorber 18 is transferred to the porous body 15 to heat the urea water adsorbed on the porous body 15. The heated urea water droplets volatilize, desorb from the porous body 15, diffuse into the exhaust gas G1, and are hydrolyzed.
このように、誘電加熱部12により攪拌部11を誘電加熱することで、排ガスG1の温度Txでは揮発できなかった尿素水を揮発させることができる。これにより、尿素水が排気通路1や選択的還元触媒装置3に直接付着することを防止するには有利になり、排気通路1や選択的還元触媒装置3に尿素水に起因する白色生成物が析出することを抑制することができる。
In this way, by dielectrically heating the stirring unit 11 by the dielectric heating unit 12, it is possible to volatilize the urea water that could not be volatilized at the temperature Tx of the exhaust gas G1. This is advantageous in preventing the urea water from directly adhering to the exhaust passage 1 and the selective reduction catalyst device 3, and white products caused by the urea water are formed in the exhaust passage 1 and the selective reduction catalyst device 3. Precipitation can be suppressed.
誘電加熱部12は攪拌部11を誘電加熱により加熱する。誘電加熱は、誘導加熱に比して均一加熱、迅速加熱、選択加熱の点で優れる。つまり、誘電加熱部12は時々刻々と変化する排ガスG1の温度Txに対して迅速加熱することで、加熱遅れを回避するには有利になる。また、誘電加熱部12は選択加熱により攪拌部11のみを加熱するのに有利になる。
The dielectric heating unit 12 heats the stirring unit 11 by dielectric heating. Dielectric heating is superior to induction heating in terms of uniform heating, rapid heating, and selective heating. That is, the dielectric heating unit 12 is advantageous in avoiding the heating delay by rapidly heating the temperature Tx of the exhaust gas G1 which changes from moment to moment. Further, the dielectric heating unit 12 is advantageous for heating only the stirring unit 11 by selective heating.
既述した実施形態で、攪拌装置10は多孔質体15を有する攪拌部11および誘電加熱部12の両方を備えているが、攪拌装置10は誘電加熱部12が無く、多孔質体15を有する攪拌部11のみで構成されてもよく、攪拌装置10は多孔質体15を有さない攪拌部11および誘電加熱部12で構成されてもよい。
In the above-described embodiment, the stirring device 10 includes both the stirring unit 11 having the porous body 15 and the dielectric heating unit 12, but the stirring device 10 does not have the dielectric heating unit 12 and has the porous body 15. The stirring unit 11 may be composed of only the stirring unit 11, and the stirring device 10 may be composed of the stirring unit 11 and the dielectric heating unit 12 which do not have the porous body 15.
前述したとおり、攪拌装置10は攪拌部11が多孔質体15を有することで、加水分解できなかった液状あるいは液滴状の尿素水を吸着することができる。また、攪拌装置10は誘電加熱部12により攪拌部11を誘電加熱することで、排ガスG1の温度Txでは揮発できなかった尿素水を揮発させることができる。
As described above, since the stirring unit 11 has the porous body 15, the stirring device 10 can adsorb liquid or droplet urea water that could not be hydrolyzed. Further, the stirring device 10 can volatilize urea water that could not be volatilized at the temperature Tx of the exhaust gas G1 by dielectrically heating the stirring unit 11 by the dielectric heating unit 12.
これらに対して、多孔質体15を有する攪拌部11および誘電加熱部12の両方を備える攪拌装置10は、加水分解できなかった液状あるいは液滴状の尿素水を多孔質体15で吸着する。ついで、攪拌装置10は排ガスG1の温度Txでは吸着したその尿素水を揮発できない場合に、誘電加熱部12により攪拌部11を誘電加熱することで、吸着した尿素水を揮発させることができる。
On the other hand, the stirring device 10 including both the stirring unit 11 having the porous body 15 and the dielectric heating unit 12 adsorbs the liquid or droplet-shaped urea water that could not be hydrolyzed by the porous body 15. Then, when the stirring device 10 cannot volatilize the adsorbed urea water at the temperature Tx of the exhaust gas G1, the adsorbed urea water can be volatilized by dielectrically heating the stirring unit 11 by the dielectric heating unit 12.
このように、多孔質体15を有する攪拌部11および誘電加熱部12の両方を備える攪拌装置10によれば、どちらか一方を備えない攪拌装置に比して、尿素水が排気通路や選択的還元触媒装置に直接付着することを防止するには有利になり、排気通路や選択的還元触媒装置に尿素水に起因する白色生成物が析出することを抑制することができる。
As described above, according to the stirring device 10 including both the stirring unit 11 having the porous body 15 and the dielectric heating unit 12, the urea water is selectively used in the exhaust passage and as compared with the stirring device not provided with either one. It is advantageous to prevent direct adhesion to the reduction catalyst device, and it is possible to suppress precipitation of white products due to urea water in the exhaust passage and the selective reduction catalyst device.
攪拌装置10が有する多孔質体15が吸着可能な尿素水の量を予め実験や試験により設定し、排ガスG1の温度Txでは尿素水を揮発できない場合に、尿素水噴射弁2から噴射される尿素水の噴射量を多孔質体15から尿素水が飛び散らない量にするとよい。
The amount of urea water that can be adsorbed by the porous body 15 of the stirrer 10 is set in advance by experiments and tests, and when urea water cannot be volatilized at the temperature Tx of the exhaust gas G1, urea is injected from the urea water injection valve 2. The amount of water jetted may be such that urea water does not scatter from the porous body 15.
また、多孔質体15を排ガスG1の流れに関して攪拌部11よりも下流側で、選択的還元触媒装置3の上流側の排気通路1における底部に設置してもよい。ここでいう、排気通路1における底部とは液状あるいは液滴の尿素水が付着し易い場所である。排気通路1における多孔質体15を設置する場所は、攪拌部11の近傍が好ましい。また、排気通路1に設置された多孔質体15の細孔の大きさは管中心から管径方向外側に向かって小さくなることが望ましい。
Further, the porous body 15 may be installed at the bottom of the exhaust passage 1 on the upstream side of the selective reduction catalyst device 3 on the downstream side of the stirring unit 11 with respect to the flow of the exhaust gas G1. The bottom portion of the exhaust passage 1 here is a place where liquid or droplet urea water easily adheres. The place where the porous body 15 is installed in the exhaust passage 1 is preferably in the vicinity of the stirring unit 11. Further, it is desirable that the size of the pores of the porous body 15 installed in the exhaust passage 1 decreases from the center of the pipe toward the outside in the pipe radial direction.
排気通路1に設置された多孔質体15に当接する電波吸収体18を備えるとともに、その電波吸収体18に向けて電波を発振する電波発振器19を備えてもよい。
A radio wave absorber 18 that abuts on the porous body 15 installed in the exhaust passage 1 may be provided, and a radio wave oscillator 19 that oscillates a radio wave toward the radio wave absorber 18 may be provided.
既述した実施形態で、電波吸収体18を羽根14の先端部に配置し、多孔質体15を羽根14の尿素水噴射弁2の側に向いた面の全域のうちの先端部を除いた部位を覆うように配置する構成を例示したが、電波吸収体18の尿素水噴射弁2の側に向いた面に多孔質体15を配置してもよい。
In the above-described embodiment, the radio wave absorber 18 is arranged at the tip of the blade 14, and the porous body 15 is removed from the entire surface of the blade 14 facing the urea water injection valve 2. Although the configuration in which the portion is arranged so as to cover the portion is illustrated, the porous body 15 may be arranged on the surface of the radio wave absorber 18 facing the urea water injection valve 2.
本出願は、2019年6月28日付で出願された日本国特許出願(特願2019-121555)に基づくものであり、その内容はここに参照として取り込まれる。
This application is based on a Japanese patent application (Japanese Patent Application No. 2019-121555) filed on June 28, 2019, the contents of which are incorporated herein by reference.
本開示に係る攪拌装置は、排気通路や選択的還元触媒装置に尿素水に起因する白色生成物が析出することを抑制することができる点において有用である。
The stirring device according to the present disclosure is useful in that it can suppress the precipitation of white products caused by urea water in the exhaust passage and the selective reduction catalyst device.
1 排気通路
2 尿素水噴射弁
3 選択的還元触媒装置
10 攪拌装置
11 攪拌部
15 多孔質体 1Exhaust passage 2 Urea water injection valve 3 Selective reduction catalyst device 10 Stirrer 11 Stirrer 15 Porous body
2 尿素水噴射弁
3 選択的還元触媒装置
10 攪拌装置
11 攪拌部
15 多孔質体 1
Claims (5)
- 排ガスが通過する排気通路の中途位置に配置された尿素水噴射弁とこの尿素水噴射弁よりも排ガスの流れに関して下流側に配置された選択的還元触媒装置との間に配置された攪拌部を備える攪拌装置において、前記攪拌部はその前記尿素水噴射弁の側に向いた面に尿素水を吸着可能な多孔質体を有することを特徴とする攪拌装置。 A stirring unit arranged between the urea water injection valve arranged in the middle of the exhaust passage through which the exhaust gas passes and the selective reduction catalyst device arranged on the downstream side with respect to the flow of the exhaust gas from the urea water injection valve. A stirring device provided, wherein the stirring unit has a porous body capable of adsorbing urea water on a surface facing the urea water injection valve.
- 前記多孔質体は金属繊維が交絡して成る金属布で構成される請求項1に記載の攪拌装置。 The stirring device according to claim 1, wherein the porous body is made of a metal cloth in which metal fibers are entangled.
- 前記多孔質体は複数の前記金属布が排ガスの流れる方向に積層して成る請求項2に記載の攪拌装置。 The stirring device according to claim 2, wherein the porous body is formed by laminating a plurality of the metal cloths in a direction in which exhaust gas flows.
- 前記多孔質体の細孔の大きさは排ガスの流れに関して上流側から下流側に向かって小さくなる請求項1~3のいずれか1項に記載の攪拌装置。 The stirring device according to any one of claims 1 to 3, wherein the size of the pores of the porous body decreases from the upstream side to the downstream side with respect to the flow of exhaust gas.
- 排ガスの流れる方向に見て前記多孔質体の外縁部に当接した電波吸収体と前記排気通路の外側に配置された電波発振器とを有する誘電加熱部を備え、前記多孔質体は前記電波発振器から出力された電波を吸収した前記電波吸収体からの伝熱により加熱される請求項1~4のいずれか1項に記載の攪拌装置。 The porous body is provided with a dielectric heating unit having a radio wave absorber abutting on an outer edge portion of the porous body and a radio wave oscillator arranged outside the exhaust passage when viewed in the direction of flow of exhaust gas, and the porous body is the radio wave oscillator. The stirring device according to any one of claims 1 to 4, which is heated by heat transfer from the radio wave absorber that has absorbed radio waves output from.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2019121555A JP2021008821A (en) | 2019-06-28 | 2019-06-28 | Stirring device |
JP2019-121555 | 2019-06-28 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2020262589A1 true WO2020262589A1 (en) | 2020-12-30 |
Family
ID=74061264
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2020/025154 WO2020262589A1 (en) | 2019-06-28 | 2020-06-26 | Stirring device |
Country Status (2)
Country | Link |
---|---|
JP (1) | JP2021008821A (en) |
WO (1) | WO2020262589A1 (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2826973A1 (en) * | 2013-07-18 | 2015-01-21 | FPT Motorenforschung AG | System for preventing the urea crystal formation within an exhaust gas after treatment system |
JP2017106426A (en) * | 2015-12-11 | 2017-06-15 | 三菱自動車工業株式会社 | Exhaust emission control device |
JP2017172332A (en) * | 2016-03-18 | 2017-09-28 | いすゞ自動車株式会社 | engine |
WO2017198601A1 (en) * | 2016-05-18 | 2017-11-23 | Volvo Truck Corporation | An exhaust gas treatment system with inductive heating and a method for controlling the same |
JP2018165488A (en) * | 2017-03-28 | 2018-10-25 | トヨタ自動車株式会社 | Heating device of exhaust emission control catalyst |
-
2019
- 2019-06-28 JP JP2019121555A patent/JP2021008821A/en active Pending
-
2020
- 2020-06-26 WO PCT/JP2020/025154 patent/WO2020262589A1/en active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2826973A1 (en) * | 2013-07-18 | 2015-01-21 | FPT Motorenforschung AG | System for preventing the urea crystal formation within an exhaust gas after treatment system |
JP2017106426A (en) * | 2015-12-11 | 2017-06-15 | 三菱自動車工業株式会社 | Exhaust emission control device |
JP2017172332A (en) * | 2016-03-18 | 2017-09-28 | いすゞ自動車株式会社 | engine |
WO2017198601A1 (en) * | 2016-05-18 | 2017-11-23 | Volvo Truck Corporation | An exhaust gas treatment system with inductive heating and a method for controlling the same |
JP2018165488A (en) * | 2017-03-28 | 2018-10-25 | トヨタ自動車株式会社 | Heating device of exhaust emission control catalyst |
Also Published As
Publication number | Publication date |
---|---|
JP2021008821A (en) | 2021-01-28 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US9856774B2 (en) | Engine exhaust system | |
US8707684B2 (en) | Control method and apparatus for regenerating a particulate filter | |
US8091341B2 (en) | Exhaust gas purification method and exhaust gas purification system | |
CN101922329B (en) | Apparatus and method for regenerating exhaust filter | |
EP2663749B1 (en) | Reductant delivery device | |
CN109424402B (en) | Double-walled mixer with active heat transfer | |
CN103161546B (en) | Selective catalytic reduction (scr) system for nox storage | |
CN102817674B (en) | Electronically heated hydrocarbon (HC) adsorber | |
US8756917B2 (en) | Control apparatus for temperature excursions within an exhaust gas treatment system | |
CN106030063A (en) | Exhaust gas post treatment system | |
US10961887B2 (en) | Integrated reductant mixer and heater apparatus for exhaust treatment systems | |
US20120110986A1 (en) | Device for evaporating a urea-water solution, method for operating the device and motor vehicle | |
US9476336B2 (en) | Container having a heating device for a tank for storing a liquid additive and motor vehicle having a tank | |
JP2021008823A (en) | Stirring device | |
WO2020262589A1 (en) | Stirring device | |
US20240110499A1 (en) | Valve arrangement for split-flow close-coupled catalyst | |
US9482131B2 (en) | Exhaust system with zone coated catalyst | |
CN112576345B (en) | Decomposition tube for heated dosing device | |
JP2010112230A (en) | Exhaust emission control device | |
JP2014234715A (en) | Exhaust emission control device | |
CN103573348A (en) | Exhaust treatment system for internal combustion engine | |
JPH07222912A (en) | Exhaust gas purifying device for vehicle | |
US20130125534A1 (en) | Electrically heated particulate filter restrike methods and systems | |
CN218062434U (en) | Catalytic and heating mixer for an aftertreatment system and aftertreatment system | |
CN221299293U (en) | Tail gas treatment device and be equipped with its car |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 20833488 Country of ref document: EP Kind code of ref document: A1 |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 20833488 Country of ref document: EP Kind code of ref document: A1 |