EP2716884A1 - Exhaust purification device for internal combustion engine - Google Patents
Exhaust purification device for internal combustion engine Download PDFInfo
- Publication number
- EP2716884A1 EP2716884A1 EP11866883.9A EP11866883A EP2716884A1 EP 2716884 A1 EP2716884 A1 EP 2716884A1 EP 11866883 A EP11866883 A EP 11866883A EP 2716884 A1 EP2716884 A1 EP 2716884A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- exhaust gas
- gas flow
- forming portion
- flow forming
- passage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 238000000746 purification Methods 0.000 title claims abstract description 27
- 238000002485 combustion reaction Methods 0.000 title claims abstract description 20
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 40
- 239000003054 catalyst Substances 0.000 claims abstract description 35
- 238000011144 upstream manufacturing Methods 0.000 claims description 7
- 239000000243 solution Substances 0.000 description 11
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 10
- 239000004202 carbamide Substances 0.000 description 10
- 238000002347 injection Methods 0.000 description 6
- 239000007924 injection Substances 0.000 description 6
- 238000010531 catalytic reduction reaction Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 239000013618 particulate matter Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- WTHDKMILWLGDKL-UHFFFAOYSA-N urea;hydrate Chemical compound O.NC(N)=O WTHDKMILWLGDKL-UHFFFAOYSA-N 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
Images
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
- B01F25/40—Static mixers
- B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
- B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
- B01F25/431—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor
- B01F25/4316—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor the baffles being flat pieces of material, e.g. intermeshing, fixed to the wall or fixed on a central rod
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
- F01N3/28—Construction of catalytic reactors
- F01N3/2892—Exhaust flow directors or the like, e.g. upstream of catalytic device
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
- B01F23/20—Mixing gases with liquids
- B01F23/21—Mixing gases with liquids by introducing liquids into gaseous media
- B01F23/213—Mixing gases with liquids by introducing liquids into gaseous media by spraying or atomising of the liquids
- B01F23/2132—Mixing gases with liquids by introducing liquids into gaseous media by spraying or atomising of the liquids using nozzles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
- B01F25/30—Injector mixers
- B01F25/31—Injector mixers in conduits or tubes through which the main component flows
- B01F25/313—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit
- B01F25/3131—Injector mixers in conduits or tubes through which the main component flows wherein additional components are introduced in the centre of the conduit with additional mixing means other than injector mixers, e.g. screens, baffles or rotating elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
- B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
- B01F25/40—Static mixers
- B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
- B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
- B01F25/431—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor
- B01F25/43197—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor characterised by the mounting of the baffles or obstructions
- B01F25/431974—Support members, e.g. tubular collars, with projecting baffles fitted inside the mixing tube or adjacent to the inner wall
-
- 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
- F01N2240/20—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 flow director or deflector
-
- 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
-
- 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
- F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
-
- 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]
Definitions
- the first gas flow forming portion is provided at a central portion of the dispersing unit, and the second gas flow forming portion is provided outside the central portion independently from the first gas flow forming portion.
- the resistance of the exhaust gas is increased in the first gas flow forming portion as compared with the second gas flow forming portion. Therefore, the velocity of the second gas flow is faster than the velocity of the first gas flow. Accordingly, the first gas flow is pushed and returned by the second gas flow toward the central axis of the exhaust gas passage from the side of the wall surface of the exhaust gas passage. Therefore, it is possible to further suppress the first gas flow from being directed to the wall surface of the exhaust gas passage. Accordingly, it is possible to further suppress the addition agent from being deviated in the vicinity of the wall surface of the exhaust gas passage.
- the disperser 5 is provided with a cylinder portion 51 which is formed so that the outer diameter is smaller than the inner diameter of the exhaust gas passage 2 and the hollow cylindrical shape coaxial with the central axis of the exhaust gas passage 2 is provided.
- a plurality of plates 52 having the same shape extend from the inner circumferential surface of the cylinder portion 51 toward the central axis.
- the plurality of plates 52 are arranged radially at equal angles about the center of the central axis of the cylinder portion 51.
- the central axes of the respective plates 52 which extend from the inner circumferential surface of the cylinder portion 51 to arrive at the forward ends of the plates 52, are perpendicular to the central axis direction of the cylinder portion 51.
- the length which ranges from the inner circumferential surface of the cylinder portion 51 to the forward end of the plate 52, is smaller than the radius of the cylinder portion 51, and the respective plates 52 are provided so that they are not brought in contact with each other.
- Each of the plates 52 is inclined by a predetermined angle with respect to the central axis of the cylinder portion 51. Further, a gap is provided between the plate 52 and the plate 52 so that the exhaust gas can flow.
- the plates 52 are arranged as described above, and thus the exhaust gas swirls about the center of the central axis of the cylinder portion 51.
- the flow direction of the exhaust gas is changed by the plurality of plates 52, and the exhaust gas swirls about the center of the central axis of the exhaust gas passage 2. Accordingly, when the addition agent is supplied toward the first gas flow forming portion 54, then the addition agent and the exhaust gas swirl, and thus the addition agent is dispersed in the first gas flow.
- the second gas flow is absent, it is feared that the addition agent contained in the first gas flow may be deviated by the centrifugal force on the side of the wall surface of the exhaust gas passage 2.
- the first gas flow forming portion 54 and the second gas flow forming portion 55 are formed so that passage for the exhaust gas, which is formed in the first gas flow forming portion 54, has the cross-sectional area that is larger than the cross-sectional area of the passage for the exhaust gas which is formed in the second gas flow forming portion 55. Accordingly, the resistance of the exhaust gas is large in the first gas flow forming portion 54 as compared with the second gas flow forming portion 55. That is, the first gas flow forming portion 54 and the second gas flow forming portion 55 are formed so that the resistance, which is brought about when the exhaust gas passes through the first gas flow forming portion 54, is larger than the resistance which is brought about when the exhaust gas passes through the second gas flow forming portion 55.
- the velocity of the second gas flow is faster than the velocity of the first gas flow. Accordingly, the first gas flow is pushed and returned by the second gas flow from the side of the wall surface of the exhaust gas passage 2 to the side of the central axis of the exhaust gas passage 2. Therefore, it is possible to suppress the addition agent from being deviated on the side of the wall surface of the exhaust gas passage 2.
- the optimum shapes of the first gas flow forming portion 54 and the second gas flow forming portion 55 can be determined, for example, by an experiment.
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Dispersion Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Exhaust Gas After Treatment (AREA)
Abstract
Description
- The present invention relates to an exhaust gas purification apparatus for an internal combustion engine.
- A technique is known in relation to an SCR system provided with a selective catalytic reduction NOx catalyst and an injection valve for injecting an aqueous urea solution (urea-water solution), wherein a disperser is provided between the selective catalytic reduction NOx catalyst and the injection valve in order to disperse the aqueous urea solution (see, for example, Patent Document 1). The exhaust gas and the aqueous urea solution are allowed to swirl by means of the disperser. Therefore, the mixing of the aqueous urea solution and the exhaust gas and the vaporization are facilitated.
- Another technique is known, wherein the exhaust gas is allowed to flow through only an outer circumferential side of a disperser (see, for example, Patent Document 2). In this technique, a central portion of the disperser has a protruding shape directed to the downstream side in the flow direction of the exhaust gas, and the central portion is closed so that the exhaust gas does not flow therethrough.
- Still another technique is known, wherein a space is provided between a disperser and an exhaust tube (see, for example, Patent Document 3).
- In the meantime, when the flow direction of the exhaust gas is changed by the disperser, it is feared that the reducing agent, which is contained in the exhaust gas, may be directed to the wall surface of the exhaust gas passage. For example, when the exhaust gas is allowed to swirl by the disperser, the aqueous urea solution, which is contained in the exhaust gas, is deviated or one-sided in the vicinity of the wall surface of the exhaust tube on account of the centrifugal force in some cases. If the aqueous urea solution adheres to the wall surface of the exhaust tube, it is feared that any deposit or precipitate originating from urea may be accumulated or piled up on the wall surface of the exhaust tube. Further, the aqueous urea solution, which arrives at the selective catalytic reduction NOx catalyst, is decreased by the amount of adhesion to the wall surface of the exhaust tube. Therefore, it is feared that the purification rate of NOx may be lowered on account of the shortage of the aqueous urea solution in the selective catalytic reduction NOx catalyst.
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- Patent Document 1:
JP2008-274941A - Patent Document 2:
JP2008-144644A - Patent Document 3:
JP2008-280999A - An object of the present invention is to suppress any deviation of an addition agent to be supplied into an exhaust gas discharged from an internal combustion engine so that the addition agent is dispersed more uniformly. Solution for the Task:
- In order to achieve the object described above, according to the present invention, there is provided an exhaust gas purification apparatus for an internal combustion engine, comprising:
- an exhaust gas purification catalyst which is provided for an exhaust gas passage of the internal combustion engine;
- a supply unit which is provided for the exhaust gas passage at a position upstream from the exhaust gas purification catalyst and which supplies an addition agent to the exhaust gas purification catalyst; and
- a dispersing unit which is provided between the exhaust gas purification catalyst and the supply unit and which disperses the addition agent, wherein:
- the dispersing unit includes a first gas flow forming portion and a second gas flow forming portion; and
- the first gas flow forming portion and the second gas flow forming portion are formed so that a first gas flow having passed through the first gas flow forming portion and a second gas flow having passed through the second gas flow forming portion interfere with each other.
- In this construction, when the addition agent is supplied from the supply unit, the addition agent flows into the dispersing unit. In the dispersing unit, for example, it is also appropriate that the flow direction of the exhaust gas is changed and/or the disturbance of the exhaust gas is strengthened. The first gas flow having passed through the first gas flow forming portion and the second gas flow having passed through the second gas flow forming portion interfere with each other on the downstream side from the dispersing unit. In this way, the both gas flows interfere with each other, and thus the deviation of the addition agent is decreased as compared with a case in which it is assumed that each of the first gas flow and the second gas flow flows singly. Accordingly, it is possible to suppress the addition agent from being deviated or one-sided in the vicinity of the wall surface of the exhaust gas passage.
- In the present invention, it is also preferable that the first gas flow forming portion is provided at a central portion of the dispersing unit, and the second gas flow forming portion is provided outside the central portion independently from the first gas flow forming portion.
- The addition agent may be supplied so that the addition agent passes through only the first gas flow forming portion, or the addition agent may be supplied so that the addition agent passes through the first gas flow forming portion and the second gas flow forming portion. That is, the addition agent may be supplied so that the addition agent is contained in at least the first gas flow. The first gas flow forming portion is provided on the central axis side of the exhaust gas passage, and the second gas flow forming portion is provided on the side of the wall surface of the exhaust gas passage as compared with the first gas flow forming portion. The second gas flow forming portion may be a space disposed between the first gas flow forming portion and the wall surface of the exhaust gas passage. The flow direction of the exhaust gas is changed in the dispersing unit, and thus the swirling flow, which swirls, for example, about the center of the central axis of the exhaust gas passage, is generated. The swirling flow may be generated in only the first gas flow forming portion. The disturbance of the exhaust gas may be strengthened by changing the flow direction of the exhaust gas in the dispersing unit.
- The second gas flow forming portion is provided outside the first gas flow forming portion, and thus the second gas flow is formed around the first gas flow. Further, the first gas flow having passed through the first gas flow forming portion and the second gas flow having passed through the second gas flow forming portion interfere with each other. Thus, the second gas flow pushes and returns the first gas flow toward the central axis. Accordingly, it is possible to suppress the first gas flow from being directed to the wall surface of the exhaust gas passage. Therefore, it is possible to suppress the addition agent from being deviated or one-sided in the vicinity of the wall surface of the exhaust gas passage.
- In the present invention, it is also preferable that a passage for the exhaust gas, which is formed in the first gas flow forming portion, has a cross-sectional area which is larger than a cross-sectional area of a passage for the exhaust gas which is formed in the second gas flow forming portion.
- Accordingly, the resistance of the exhaust gas is increased in the first gas flow forming portion as compared with the second gas flow forming portion. Therefore, the velocity of the second gas flow is faster than the velocity of the first gas flow. Accordingly, the first gas flow is pushed and returned by the second gas flow toward the central axis of the exhaust gas passage from the side of the wall surface of the exhaust gas passage. Therefore, it is possible to further suppress the first gas flow from being directed to the wall surface of the exhaust gas passage. Accordingly, it is possible to further suppress the addition agent from being deviated in the vicinity of the wall surface of the exhaust gas passage.
- In the present invention, it is also preferable that the second gas flow forming portion is formed so that a flow direction of the exhaust gas allowed to pass through the second gas flow forming portion is a direction which is directed toward a central axis of the exhaust gas passage or parallel to a wall surface of the exhaust gas passage.
- That is, the second gas flow is prohibited from being directed to the wall surface of the exhaust gas passage, and thus the first gas flow can be pushed and returned by the second gas flow in the direction directed to the central axis of the exhaust gas passage. Therefore, it is possible to suppress the first gas flow from being directed to the wall surface of the exhaust gas passage. Accordingly, it is possible to further suppress the addition agent from being deviated in the vicinity of the wall surface of the exhaust gas passage.
- According to the present invention, it is possible to suppress any deviation of the addition agent to be supplied into the exhaust gas discharged from the internal combustion engine so that the addition agent is dispersed more uniformly.
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Fig. 1 shows a schematic arrangement of an exhaust gas purification apparatus for an internal combustion engine according to an embodiment. -
Fig. 2 shows a disperser as viewed from the upstream side in the flow direction of the exhaust gas. -
Fig. 3 shows a sectional view as obtained when the disperser is sectioned in parallel to the flow direction of the exhaust gas. - A specified embodiment of the exhaust gas purification apparatus for the internal combustion engine according to the present invention will be explained below on the basis of the drawings.
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Fig. 1 shows a schematic arrangement of an exhaust gas purification apparatus for an internal combustion engine according to an embodiment of the present invention. The internal combustion engine 1 shown inFig. 1 may be either a diesel engine or a gasoline engine. - An
exhaust gas passage 2 is connected to the internal combustion engine 1. An exhaust gas purification catalyst 3 (hereinafter simply referred to as "catalyst 3") is provided at an intermediate position of theexhaust gas passage 2. Thecatalyst 3 is such a catalyst that the temperature is raided, the exhaust gas is purified, or the purification ability is restored by supplying an addition agent. As for thecatalyst 3, it is possible to exemplify, for example, an absorption reduction type NOx catalyst, a selective catalytic reduction NOx catalyst, a three way catalyst, an oxidation catalyst, and a hydrolysis catalyst. Thecatalyst 3 may be a catalyst having an oxidation function. Further, a particulate filter, which collects the particulate matter, may be provided, and the particulate filter may be a carrier for thecatalyst 3. Thecatalyst 3 may be arranged upstream from the particulate filter. - An
injection valve 4, which injects the addition agent into the exhaust gas, is provided for theexhaust gas passage 2 at a position disposed on the upstream side from thecatalyst 3. The addition agent can be, for example, a reducing agent or an oxidizing agent. For example, fuel, aqueous urea solution, or ammonia can be used for the addition agent. What is used for the addition agent is determined depending on the type of thecatalyst 3. In this embodiment, theinjection valve 4 corresponds to the supply unit according to the present invention. - A
disperser 5, which disperses the addition agent into the exhaust gas, is provided for the exhaust gas passage at a position disposed downstream from theinjection valve 4 and upstream from thecatalyst 3. In this embodiment, thedisperser 5 corresponds to the dispersing unit according to the present invention. - In this context,
Fig. 2 shows thedisperser 5 as viewed from the upstream side in the flow direction of the exhaust gas.Fig. 3 shows a sectional view as obtained when thedisperser 5 is sectioned in parallel to the flow direction of the exhaust gas. - The
disperser 5 is provided with acylinder portion 51 which is formed so that the outer diameter is smaller than the inner diameter of theexhaust gas passage 2 and the hollow cylindrical shape coaxial with the central axis of theexhaust gas passage 2 is provided. A plurality ofplates 52 having the same shape extend from the inner circumferential surface of thecylinder portion 51 toward the central axis. The plurality ofplates 52 are arranged radially at equal angles about the center of the central axis of thecylinder portion 51. The central axes of therespective plates 52, which extend from the inner circumferential surface of thecylinder portion 51 to arrive at the forward ends of theplates 52, are perpendicular to the central axis direction of thecylinder portion 51. The length, which ranges from the inner circumferential surface of thecylinder portion 51 to the forward end of theplate 52, is smaller than the radius of thecylinder portion 51, and therespective plates 52 are provided so that they are not brought in contact with each other. Each of theplates 52 is inclined by a predetermined angle with respect to the central axis of thecylinder portion 51. Further, a gap is provided between theplate 52 and theplate 52 so that the exhaust gas can flow. Theplates 52 are arranged as described above, and thus the exhaust gas swirls about the center of the central axis of thecylinder portion 51. - For example, the shape, the number, and the angle of the
plates 52 may be determined, for example, by an experiment. Any other member, which increases the disturbance in relation to the exhaust gas or which swirls the exhaust gas, may be provided in place of theplates 52. For example, one plate may be provided at a position disposed on the central axis side as compared with thecylinder portion 51. A plurality of holes may be provided through the plate. - A plurality of fixing
portions 53, which connect the outer wall of thecylinder portion 51 and the inner wall of theexhaust gas passage 2 and which fix thecylinder portion 51 in theexhaust gas passage 2, are provided outside thecylinder portion 51. A space, through which the exhaust gas can flow, is provided between thecylinder portion 51 and theexhaust gas passage 2. - In the
disperser 5 constructed as described above, the exhaust gas flows inside thecylinder portion 51 and outside thecylinder portion 51 respectively. In this embodiment, the inner side, which is disposed inside thecylinder portion 51, is referred to as "first gasflow forming portion 54", and the outer side, which is disposed outside thecylinder portion 51, is referred to as "second gasflow forming portion 55". Further, the gas flow, which passes through the first gasflow forming portion 54, is referred to as "first gas flow", and the gas flow, which passes through the second gasflow forming portion 55, is referred to as "second gas flow". - When the exhaust gas passes through the first gas
flow forming portion 54, then the flow direction of the exhaust gas is changed by the plurality ofplates 52, and the exhaust gas swirls about the center of the central axis of theexhaust gas passage 2. Accordingly, when the addition agent is supplied toward the first gasflow forming portion 54, then the addition agent and the exhaust gas swirl, and thus the addition agent is dispersed in the first gas flow. In this context, if it is assumed that the second gas flow is absent, it is feared that the addition agent contained in the first gas flow may be deviated by the centrifugal force on the side of the wall surface of theexhaust gas passage 2. - In relation thereto, the first gas
flow forming portion 54 and the second gasflow forming portion 55 are formed so that passage for the exhaust gas, which is formed in the first gasflow forming portion 54, has the cross-sectional area that is larger than the cross-sectional area of the passage for the exhaust gas which is formed in the second gasflow forming portion 55. Accordingly, the resistance of the exhaust gas is large in the first gasflow forming portion 54 as compared with the second gasflow forming portion 55. That is, the first gasflow forming portion 54 and the second gasflow forming portion 55 are formed so that the resistance, which is brought about when the exhaust gas passes through the first gasflow forming portion 54, is larger than the resistance which is brought about when the exhaust gas passes through the second gasflow forming portion 55. Therefore, the velocity of the second gas flow is faster than the velocity of the first gas flow. Accordingly, the first gas flow is pushed and returned by the second gas flow from the side of the wall surface of theexhaust gas passage 2 to the side of the central axis of theexhaust gas passage 2. Therefore, it is possible to suppress the addition agent from being deviated on the side of the wall surface of theexhaust gas passage 2. The optimum shapes of the first gasflow forming portion 54 and the second gasflow forming portion 55 can be determined, for example, by an experiment. - Further, the second gas
flow forming portion 55 is formed so that the flow direction of the exhaust gas allowed to pass through the second gasflow forming portion 55 is separated from the wall surface of theexhaust gas passage 2 or parallel thereto. That is, the second gas flow is prohibited from being directed to the wall surface of theexhaust gas passage 2. For example, the resistance, which is brought about when the exhaust gas passes through the first gasflow forming portion 54, is made larger than the resistance which is brought about when the exhaust gas passes through the second gasflow forming portion 55, and thus the second gas flow advances in the central axis direction of theexhaust gas passage 2. Accordingly, it is possible to suppress the first gas flow from being directed to the wall surface of theexhaust gas passage 2. - In this way, the first gas flow and the second gas flow interfere with each other on the downstream side from the
disperser 5. Accordingly, it is possible to suppress the addition agent from being deviated or one-sided in the vicinity of the wall surface of theexhaust gas passage 2. Further, the addition agent can be dispersed in a short distance, and hence it is possible to shorten the distance between thedisperser 5 and thecatalyst 3. Therefore, it is easy to install thedisperser 5 as compared with the conventional technique. Further, an appropriate amount of the addition agent can be also supplied to the vicinity of the central axis of thecatalyst 3, because it is possible to suppress the addition agent from being deviated or one-sided in the vicinity of the wall surface of theexhaust gas passage 2. Accordingly, it is possible to improve the purification performance for purifying the exhaust gas. - 1: internal combustion engine, 2: exhaust gas passage, 3: exhaust gas purification catalyst, 4: injection valve, 5: disperser, 51: cylinder portion, 52: plate, 53: fixing portion, 54: first gas flow forming portion, 55: second gas flow forming portion.
Claims (4)
- An exhaust gas purification apparatus for an internal combustion engine, comprising:an exhaust gas purification catalyst which is provided for an exhaust gas passage of the internal combustion engine;a supply unit which is provided for the exhaust gas passage at a position upstream from the exhaust gas purification catalyst and which supplies an addition agent to the exhaust gas purification catalyst; anda dispersing unit which is provided between the exhaust gas purification catalyst and the supply unit and which disperses the addition agent, wherein:the dispersing unit includes a first gas flow forming portion and a second gas flow forming portion; andthe first gas flow forming portion and the second gas flow forming portion are formed so that a first gas flow having passed through the first gas flow forming portion and a second gas flow having passed through the second gas flow forming portion interfere with each other.
- The exhaust gas purification apparatus for the internal combustion engine according to claim 1, wherein the first gas flow forming portion is provided at a central portion of the dispersing unit, and the second gas flow forming portion is provided outside the central portion independently from the first gas flow forming portion.
- The exhaust gas purification apparatus for the internal combustion engine according to claim 1 or 2, wherein a passage for the exhaust gas, which is formed in the first gas flow forming portion, has a cross-sectional area which is larger than a cross-sectional area of a passage for the exhaust gas which is formed in the second gas flow forming portion.
- The exhaust gas purification apparatus for the internal combustion engine according to any one of claims 1 to 3, wherein the second gas flow forming portion is formed so that a flow direction of the exhaust gas allowed to pass through the second gas flow forming portion is a direction which is directed toward a central axis of the exhaust gas passage or parallel to a wall surface of the exhaust gas passage.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP2011/062704 WO2012164722A1 (en) | 2011-06-02 | 2011-06-02 | Exhaust purification device for internal combustion engine |
Publications (2)
Publication Number | Publication Date |
---|---|
EP2716884A1 true EP2716884A1 (en) | 2014-04-09 |
EP2716884A4 EP2716884A4 (en) | 2014-12-03 |
Family
ID=47258607
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP11866883.9A Withdrawn EP2716884A4 (en) | 2011-06-02 | 2011-06-02 | Exhaust purification device for internal combustion engine |
Country Status (3)
Country | Link |
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EP (1) | EP2716884A4 (en) |
JP (1) | JPWO2012164722A1 (en) |
WO (1) | WO2012164722A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN105545438A (en) * | 2014-10-22 | 2016-05-04 | 丰田自动车株式会社 | Dispersion plate and internal combustion engine |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
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JP6077963B2 (en) * | 2013-07-31 | 2017-02-08 | カルソニックカンセイ株式会社 | Exhaust purification device |
JP6046568B2 (en) * | 2013-07-31 | 2016-12-14 | カルソニックカンセイ株式会社 | Exhaust purification device |
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- 2011-06-02 WO PCT/JP2011/062704 patent/WO2012164722A1/en active Application Filing
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- 2011-06-02 JP JP2013517777A patent/JPWO2012164722A1/en active Pending
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Also Published As
Publication number | Publication date |
---|---|
JPWO2012164722A1 (en) | 2014-07-31 |
WO2012164722A1 (en) | 2012-12-06 |
EP2716884A4 (en) | 2014-12-03 |
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