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CN109252921A - Box exhaust gas aftertreatment system - Google Patents

Box exhaust gas aftertreatment system Download PDF

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Publication number
CN109252921A
CN109252921A CN201710569429.6A CN201710569429A CN109252921A CN 109252921 A CN109252921 A CN 109252921A CN 201710569429 A CN201710569429 A CN 201710569429A CN 109252921 A CN109252921 A CN 109252921A
Authority
CN
China
Prior art keywords
mixing tube
flap
exhaust gas
aftertreatment system
catalytic reduction
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.)
Pending
Application number
CN201710569429.6A
Other languages
Chinese (zh)
Inventor
唐宝宝
M·艾尔玛诺坦
罗晶
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Priority to CN201710569429.6A priority Critical patent/CN109252921A/en
Publication of CN109252921A publication Critical patent/CN109252921A/en
Pending legal-status Critical Current

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust 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
    • F01N3/18Exhaust 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
    • F01N3/20Exhaust 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
    • F01N3/2066Selective catalytic reduction [SCR]
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust 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
    • F01N3/24Exhaust 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
    • F01N3/28Construction of catalytic reactors
    • F01N3/2892Exhaust flow directors or the like, e.g. upstream of catalytic device
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/10Internal combustion engine [ICE] based vehicles
    • Y02T10/12Improving ICE efficiencies

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

Abstract

A kind of box exhaust gas aftertreatment system includes: oxidation catalyzer unit and selective catalytic reduction unit arranged side by side, is respectively had a first end and a second end;Mixing tube, Upstream section is connected to the second end of oxidation catalyzer unit, tract is connected to the first end of selective catalytic reduction unit;And reducing agent jet port, it is installed on mixing tube, is entered in the tail gas of the mixing tube for reducing agent jet flow to be ejected into the second end through the oxidation catalyzer unit;Wherein, the selective catalytic reduction unit has first end cavity, and the tract of mixing tube is opened on the first end cavity;Flap is equipped in the first end cavity, the tail gas for being mixed with reducing agent that the flap is configured so that the tract through mixing tube flows into the first end cavity is guided and flowed in the first end cavity in the form of eddy flow by the flap.

Description

Box exhaust gas aftertreatment system
Technical field
This application involves a kind of box exhaust gas aftertreatment systems, for handling engine, especially diesel engine emissions Tail gas.
Background technique
It include harmful components in motor exhaust.In order to reduce the discharge amount of harmful components in tail gas, after miscellaneous Processing technique is developed.It is typically used for including various vent gas treatments in the box exhaust gas aftertreatment system of diesel engine Element usually has oxidation catalyzer (DOC), selective catalytic reduction device (SCR) and grain catcher (DPF), wherein selectivity Together with catalysis reductor can integrate with grain catcher.
In order to meet exhaust emissions requirement of greater degree, such as Europe six, six standard of state etc., after needing to improve box tail gas The performance of processing system, this requires to increase each vent gas treatment element, especially selective catalysis in box exhaust gas aftertreatment system The volume of reductor.Since the volume of selective catalytic reduction device increases, the mixed airflow of tail gas and reducing agent is caused to select Property catalysis reductor in temperature and velocity uniformity become negatively affected, and this selective catalytic reduction that will lead to tail gas is anti- Answer reduced performance.Therefore, it is intended that being improved to the structure of box exhaust gas aftertreatment system, to avoid the above problem.
Summary of the invention
The purpose of the application is to provide one kind for box exhaust gas aftertreatment system, can be improved tail gas and reduction Temperature and velocity uniformity of the mixed airflow of agent in selective catalytic reduction device.
For this purpose, the application provides a kind of box exhaust gas aftertreatment system in terms of one comprising:
Oxidation catalyzer unit and selective catalytic reduction unit arranged side by side, respectively has a first end and a second end;
Mixing tube, Upstream section is connected to the second end of oxidation catalyzer unit, tract and selective catalytic reduction list The first end connection of member;And
Reducing agent jet port, is installed on mixing tube, for being ejected into reducing agent jet flow through the oxidation catalyzer list The second end of member enters in the tail gas of the mixing tube;
Wherein, the selective catalytic reduction unit has first end cavity, and the tract of mixing tube is opened on described the One end cavity;
Flap is equipped in the first end cavity, the flap is configured so that the tract through mixing tube flows into institute State the tail gas for being mixed with reducing agent in first end cavity by the flap guide and in the form of eddy flow it is empty in the first end It is flowed in chamber.
According to a kind of embodiments possible, the flap is the circle arranged along the shell of selective catalytic reduction unit The form of segmental arc, and there is upstream edge and downstream edge, the upstream edge cloth for the flow direction of tail gas It sets in that side that the tract close to mixing tube is open.
According to a kind of embodiments possible, the position of the upstream edge in the axial direction is located at the tract opening of mixing tube Between the catalyst in selective catalytic reduction unit.
According to a kind of embodiments possible, the flap is inclined or curved, so that in the axial direction, the water conservancy diversion The downstream edge of the wing is than upstream edge closer to the first end of selective catalytic reduction unit.
According to a kind of embodiments possible, wherein be equipped with two or more along the circumferential direction successive flaps altogether.
According to a kind of embodiments possible, if there are two valve flaps substantially in a rotationally symmetrical arrangement each other.
According to a kind of embodiments possible, in the axial direction, for two along the circumferential direction successive flaps, before The downstream edge of that flap than below mutually the upstream edge of that flap closer to selective catalytic reduction unit the One end.
According to a kind of embodiments possible, the flap has the inner circumferential extended between upstream edge and downstream edge Side and outer periphery, the outer periphery is connected to or the inner wall of the shell adjacent to selective catalytic reduction unit.
According to a kind of embodiments possible, the outer periphery is formed with flange.
According to a kind of embodiments possible, the Upstream section of the mixing tube and the second end of oxidation catalyzer unit are connected to The first public cover.
According to a kind of embodiments possible, the position of the facing oxidation catalyzer unit second end of first cover Horizontal and vertical size is greater than facing to the position of mixing tube Upstream section.
According to a kind of embodiments possible, the mixing tube is single pipe fitting;Alternatively, the mixing tube by splicing each other It is constituted to multiple pipeline sections together.
According to a kind of embodiments possible, the box exhaust gas aftertreatment system further includes delivery pipe, the delivery pipe First end constitutes the discharge port of box exhaust gas aftertreatment system, the second end of the delivery pipe and the selective catalytic reduction The second end of unit is connected to the second public cover.
According to a kind of embodiments possible, the box exhaust gas aftertreatment system further includes in reducing agent jet port upstream Deflector in mixing tube is set at position, forms multiple through-holes or slit in the deflector, for so that tail gas flows through Each through-hole or slit and form multiply tail gas stream.
According to a kind of embodiments possible, the box exhaust gas aftertreatment system further includes under reductant metering jet port Hybrid element is set in mixing tube at the position of trip, and the hybrid element has guidance reducing agent and tail gas along the circumferential direction inclined The fin turned.
According to the application, flap is arranged by the first end in selective catalytic reduction device, so that urging into selectivity The mixed airflow of the tail gas and reducing agent of changing reductor is guided and forms eddy flow, so that the gaseous mixture of tail gas and reducing agent Stream flows through the catalyst in selective catalytic reduction device with more uniform temperature and speed, so that the harmful components in tail gas It can more efficiently be removed, so that the exhaust emissions that the box exhaust gas aftertreatment system of the application can satisfy greater degree is wanted It asks.
Detailed description of the invention
The aforementioned and other aspects of the application will more completely be managed and that is done with reference to the accompanying drawings is discussed in detail Solution and understanding, in which:
Fig. 1,2 are perspectives according to a kind of cross-section of the exhaust gas aftertreatment system of embodiments possible of the application Figure;
Fig. 3 is the front view of the cross-section of the exhaust gas aftertreatment system;
Fig. 4 is the local perspective view of the exhaust gas aftertreatment system, thin at selective catalytic reduction device first end to show Section;
Fig. 5 is a kind of flap knot that selective catalytic reduction device first end can be arranged in the exhaust gas aftertreatment system The perspective view of structure;
Fig. 6 is the perspective view that one of mixing tube deflector structure can be arranged in the exhaust gas aftertreatment system;
Fig. 7 is the perspective view that one of mixing tube hybrid element structure can be arranged in the exhaust gas aftertreatment system.
Specific embodiment
Present invention relates generally to a kind of box exhaust gas aftertreatment systems, for handling motor exhaust.The tail of the application Gas after-treatment system is typically adapted for use with the tail gas of processing diesel engine;However, the exhaust gas aftertreatment system is also applicable In other types of engine (some components in system may need correspondingly to change).
Fig. 1 to 3 diagrammatically illustrates a kind of box exhaust gas aftertreatment system of the application.The exhaust gas aftertreatment system is main Including the oxidation catalyzer unit 1 and selective catalytic reduction unit 2 being arranged side by side generally parallel to each other.
Oxidation catalyzer unit 1 includes the catalyst of shell and arrangement in the housing, will be started by oxidation reaction Carbon monoxide and hydrocarbon in tail gas are converted to water and carbon dioxide.
Oxidation catalyzer unit 1 and selective catalytic reduction unit 2 respectively have first end (being as shown in the figure front end) and Second end (being as shown in the figure rear end).The second end of oxidation catalyzer unit 1 is connected to the inner cavity of the first cover 3, is selectively urged The second end for changing reduction unit 2 is connected to the inner cavity of the second cover 4.
Selective catalytic reduction unit 2 includes shell 2a and the catalyst 2b being arranged in shell 2a, for by catalysis Agent and nitrogen selectively is generated with the reaction of nitrogen oxides in tail gas using reducing agent (such as aqueous solution of urea) Gas and water.The first end of selective catalytic reduction unit 2 be it is closed, catalyst 2b occupies most of sky in shell 2a Between, and first end is being left between catalyst 2b and the closed first end of selective catalytic reduction unit 2 in shell 2a Cavity 2c.
According to a kind of embodiments possible, combination has granule capturing (filtering) function in selective catalytic reduction unit 2.
The inner cavity of the second end of oxidation catalyzer unit 1 and the first cover 3 passes through mixing tube 5 and selective catalytic reduction The first end cavity 2c of unit 2 establishes connection.Specifically, the Upstream section 5a of mixing tube 5 is connected to the first cover 3 and leads to The inner cavity of first cover 3, tract 5b is connected to the shell 2a of selective catalytic reduction unit 2, and (specifically shell 2a is substantially Cylindrical side wall) and lead to first end cavity 2c.Upstream section 5a generally extends forward from the first cover 3, and may be to The inclination of the direction of oxidation catalyzer unit 1 and/or selective catalytic reduction unit 2.Tract 5b is opened on first end cavity 2c, And the central axis of tract 5b is directed toward the radial position between the central axis and shell 2a of selective catalytic reduction unit 2d It sets.
Mixing tube 5, which is designed to follow suitable path, extends to the of selective catalytic reduction unit 2 from the first cover 3 One end.For this purpose, mixing tube 5 can be spliced by multiple pipeline sections, for example, Fig. 1, shown in 2 like that with substantially straight upper Swim section 5a, substantially straight tract 5b and the middle straight line section between upstream and downstream section.The benefit of this spliced design It is convenient for manufacturing and assembling each section of mixing tube 5, and convenient for disposing other elements (if any) in mixing tube 5. It is of course also possible to mixing tube 5 be designed to the form of single-piece, in order to reduce manufacture and assembling cost.Furthermore, it is possible to will mixing Pipe 5 designs integral, such as extends along one section of crooked route, so that the flowing in mixing tube 5 is more smooth.
Delivery pipe 6 is arranged side by side substantially in parallel with oxidation catalyzer unit 1 and selective catalytic reduction unit 2, and It is connected to the inner cavity of the second cover 4.
The jet port 7 (being only shown in FIG. 2) of reductant metering module is connected to mixing close to the Upstream section 5a of mixing tube 5 Pipe 5, for spraying reducing agent (for example, aqueous solution of urea) into mixing tube 5 in a manner of metering.
Preferably, the main injection axis of the jet port 7 of reductant metering module mixing tube 5 that section facing with it Central axis is substantially consistent.For example, in the example depicted in figure 1, main injection axis and the mixing tube 5 of reductant metering module The central axis of middle straight line section is substantially consistent.
Optionally, in mixing tube 5, reductant metering module jet port 7 close to upstream, arrange deflector 8, Such as it is described hereinafter.Optionally, in addition, it in mixing tube 5, in the downstream of the jet port 7 of reductant metering module, arranges mixed Element 9 is closed, is such as described hereinafter.
In addition, arranging that one or more flaps 10 are (excellent in the first end cavity 2c of selective catalytic reduction unit 2 Two flaps being selected as in illustrative example), for generating rotation in the first end cavity 2c of selective catalytic reduction unit 2 Stream, as further described below.
In addition, the main part of 6 this three of oxidation catalyzer unit 1, selective catalytic reduction unit 2 and delivery pipe is arranged In shell 11.Shell 11 is removed to show internal structure in Fig. 1.As shown in Figure 2,3, shell 11 by front side first end Wall 11a, the second end wall of rear side, the side wall 11b between the first and second end walls are surrounded.Oxidation catalyzer unit 1, selection Property 6 this three of catalytic reduction unit 2 and delivery pipe first end all by the first end wall 11a support, second end is all by the second end wall Support, and optionally, the middle part of this three is supported by the supporting walls 12 in shell 11.First cover 3 and the second cover 4 are all pacified Loaded on the second end wall.The first end of oxidation catalyzer unit 1 equipped with from the first end wall 11a inlet port 13 outstanding forward, First cover 3 is connected with the Upstream section 5a of the second end of oxidation catalyzer unit 1 and mixing tube 5, the second cover 4 and selectivity The second end of catalytic reduction unit 2 and the second end (being as shown in the figure rear end) of delivery pipe 6 are connected.The first end of delivery pipe 6 (being as shown in the figure front end) passes through the first end wall 11a and forms discharge port 14.In addition, mixing tube 5 is connected in shell 11 Between first cover 3 and the first end of selective catalytic reduction unit 2.In this way, the box exhaust gas aftertreatment system shape of the application At from inlet port 13 to the exhaust gas flow path of discharge port 14, wherein by arrow of the tail gas of engine discharge in Fig. 1 Head F1 shown in direction through inlet port 13 flow into oxidation catalyzer unit 1 first end, in oxidation catalyzer unit 1 axially from It flows after forward direction, and enters in the first cover 3 through the second end of oxidation catalyzer unit 1.
Then, as denoted by the arrows in fig. 2, tail gas is from the Upstream section 5a that the first cover 3 enters mixing tube 5, along mixed Close pipe 5 flow, and be reduced agent metering module jet port 7 spray into reducing agent hit and it is mixed.Then, it is mixed with The tail gas of reducing agent flows into the first end cavity 2c of selective catalytic reduction unit 2 through the tract 5b of mixing tube 5.
In first end cavity 2c, the tail gas for being mixed with reducing agent is guided by flap 10 and forms eddy flow, in Fig. 3 Shown in circumferencial direction block arrow.During flowing in a manner of eddy flow, the tail gas of reducing agent is mixed with by selective catalysis Shell 2a and 10 synergy of flap of reduction unit 2 and pushed towards center, as shown in the radial thin arrow in Fig. 3, so Afterwards towards the catalyst 2b flowing in selective catalytic reduction unit 2.
Then, the tail gas for being mixed with reducing agent flows from front to back in selective catalytic reduction unit 2, flows through catalyst 2b and Chemoselective reduction occurs and removes the nitrogen oxides in tail gas.So treated tail gas from selective catalysis also The second end of former unit 2 enters in the second cover 4.Then, treated, and tail gas enters in delivery pipe 6, later from discharge port 14 discharges.From the discharge of discharge port 14, treated that tail gas can be directly discharged in atmosphere, alternatively, can be discharged into and outlet side In the subsequent exhaust pipeline sections of 14 connection of mouth.
It is appreciated that being arranged according to delivery pipe 6, the inlet port 13 and discharge port 14 of tail gas can be located at the same side, It is all located at the front side of box exhaust gas aftertreatment system in the example in the figures, this is for box exhaust gas aftertreatment system in vehicle In certain arrangements be advantageous.According to a kind of alternative embodiment, discharge can be directly opened up on the second cover 4 Port, so that inlet port 13 and discharge port 14 are located at the two sides of box exhaust gas aftertreatment system, after this is for box tail gas The other arrangements of processing system in the car may be advantageous.
Fig. 3, a pair of of the flap 10 used in the box exhaust gas aftertreatment system of the application is shown in 4.This pair is led The stream wing 10 is arranged in substantially diametrically opposed to each otherly in the first end cavity 2c of selective catalytic reduction unit 2.
As an example, each flap 10 can have construction shown in fig. 5.As shown in figure 5, each flap 10 has Less than the plate body 101 of the substantially arc section form of 180 degree, which limits first edge 102 and (generates from flap The flow direction upstream the Shang Kanshi side edge of eddy flow tail gas), second edge 103 (from flap generate eddy flow tail gas flowing To look up be downstream side edge for side) and the inner periphery 104 that is extended in the form of circular arc between the first and second edges and outer Periphery 105.Plate body 101 can be the form of plate on the whole, can also form the form of curved surface (spiral).At outer periphery 105 It is preferably formed as the flange turned down from plate body 101, in order to the determining in the shell 2a of selective catalytic reduction unit 2 of flap 10 Position and installation.
The pair of flap 10 is arranged in the first end cavity 2c of selective catalytic reduction unit 2 in this way In, i.e. their outer periphery 105 (flange) inner wall that abuts against shell 2a, inner periphery 104 is around selective catalytic reduction The central axis of unit 2.In a circumferential direction, the opening for leading to first end cavity 2c of the tract 5b of mixing tube 5 is orientated It is approximately towards the first edge 102 of first flap 10.In the axial direction of selective catalytic reduction unit 2, first water conservancy diversion The first edge 102 of the wing 10 can be between the opening and catalyst 2b of tract 5b, preferably in the axial direction close to tract The opening of 5b.Second flap 10 is arranged on position substantially successive with first flap 10 in the circumferential direction, example Such as, second flap 10 be located at on first flap 10 substantially position of rotational symmetry.The plate body of each flap 10 101 arrange transverse to the central axis of selective catalytic reduction unit 2, but the center relative to selective catalytic reduction unit 2 The vertical plane of axis slightly deflection or bending, so that in the axial direction, the second edge 103 of each flap 10 is than first edge 102 Forward (i.e. closer to the first end of selective catalytic reduction unit 2).In this way, in each flap 10 guidance tail gas with eddy flow shape During formula flows, also apply motive force axially forward to tail gas.
The first edge 102 of second flap 10 and the second edge of first flap 10 103 are in a circumferential direction It is close, it can also can be overlapped in a circumferential direction, even in a circumferential direction at a distance, but optionally It is overlapped sub-fraction.In the axial direction, the second edge of 102 to the first flaps of the first edge of second flap 10 10 103 rearward, and the first edge 102 of 103 to the first flaps of second edge 10 of second flap 10 is forward.In this way, one Tail gas can be guided to flow with cyclonic form flap 10, and also apply motive force axially forward to tail gas, this makes Tail gas flow distribution obtains more uniformly.
In the case where more than two flaps are arranged, along the circumferential direction the first and of each flap of arranged in succession Two edges can be arranged with previously described axial position.In the case where a flap is only arranged, the flap is extensible By the circular arc less than 360 degree, and it is arranged so that its second edge is more forward than first edge in the axial direction.
Various supplementary features, such as mounting characteristic, water conservancy diversion feature etc. can be set for flap.Tool shown in Fig. 5 In body example, the positioning region 106 for being installed to flap 10 on shell 2a is formed on the plate body 101 of flap 10, it is fixed The quantity in position portion 106 is preferably three or more, so as to which positioning region 106 is fastened to by shell by fasteners such as screws On the corresponding fixed structure (not shown) that body 2a stretches out.Positioning region 106 is arranged on plate body 101, is facilitated plate body 101 is steady Surely it is fixed in shell 2a.Certainly, in the enough situations of the rigidity of flap 10 itself, outer periphery 105 can also be passed through Flange is fixed on shell 2a.
In addition, being also formed with the water conservancy diversion rib 107 for dispersing mobility of tail gas rotational on the plate body 101 of flap 10.In addition, can also To form guide vane on the plate body 101 of flap 10, the guide vane is by punching from the plate body 101 of flap 10 It stretches out to water conservancy diversion, and leaves gap in plate body 101 and fraction tail gas is passed therethrough.
Other supplementary features are it is further envisaged that come out.
It is provided with flap 10 due to being arranged in the first end cavity 2c of selective catalytic reduction unit 2, so that mixing There is the tail gas of reducing agent to form eddy flow by the guidance of flap 10 and flows through the reducing agent 2b in selective catalytic reduction unit 2, and And some tail gas for being mixed with reducing agent crosses the inner periphery 104 of flap 10 and flows directly into reducing agent 2b.This structure It makes so that the tail gas for being mixed with reducing agent equably reaches the front end face for being loaded with the matrix of reducing agent 2b, so that being mixed with reducing agent Tail gas catalyst 2b is flowed through with more uniform temperature and speed.
Shown by the experiment that different location measures in the first end cavity 2c of selective catalytic reduction unit 2 By the way that flap 10 is arranged, being mixed with the tail gas of reducing agent flow velocity at various locations and temperature becomes more uniform.In this way, tail Nitrogen oxides in gas can more efficiently be removed in selective catalytic reduction unit 2, so as to meet greater degree Exhaust emissions requirement.
According to the application, the flap 10 of all kinds of different forms and quantity can be set.Flap 10 can have Different length, width, thickness, outer diameter, can office's body be arranged between each position and 2 central axis of selective catalytic reduction unit Angle.The outer periphery 105 of the stream wing 10 can abut the inner wall of the shell 2a of selective catalytic reduction unit 2 as previously described, Can also slightly there be gap between the inner wall of shell 2a.
The deflector 8 and diversion member 9 being arranged in mixing tube 5 enable to reducing agent to be better mixed with tail gas.
A kind of example of specific structure of deflector 8 is shown in Fig. 6, wherein deflector 8 includes upstream side installation end 81, downstream side support end 82 and plate-like body 83 positioned there between.Main body 83 can be strip cylindrical shape.Upstream side Installation end 81 is suitable for for deflector 8 being mounted in mixing tube 5, such as is installed to the jet port 7 of reductant metering module.Downstream side Support end 82 is suitable for being mixed pipe 5 and supports, such as the interface section clamping or solid being mixed between two adjacent tubular segments of pipe 5 It is fixed.Plate-like body 83 is obliquely arranged in mixing tube 5, is substantially located at the reduction that the jet port of reductant metering module sprays The upstream of agent jet flow.Multiple uniformly distributed through-holes or slit 84 are formed in plate-like body 83, enable tail gas flow through each through-hole or Slit 84 and form multiply tail gas stream so that each stock tail gas stream has increased mass velocity, and the flow velocity of each stock is uniform each other. So increase and the mass velocity of homogenization is conducive to uniform mixing of the reducing agent in tail gas.
A kind of example of specific structure of hybrid element 9 is shown in Fig. 7, wherein hybrid element 9 includes 91 He of cylindrical wall The multiple uniformly distributed fins 92 extended respectively from the edge axially back and forth of cylindrical wall 91 to radially inner side.The size of cylindrical wall 91 is set It counts into and is suitable for being mounted in mixing tube 5 in the downstream of the jet port of reductant metering module, so that hybrid element 9 is generally positioned at It can be reduced on the position that agent jet flow strikes.The surface of each fin 92 is tilted relative to circumferencial direction, and inclined angle can With identical.In this way, the mixed airflow of the reducing agent and tail gas that strike each fin 92 can along the circumferential direction be deflected by these fins. Under the deflecting action of whole fins 92, eddy flow will form.This eddy flow is conducive to uniform mixing of the reducing agent in tail gas.
The feature for being conducive to improve mixture homogeneity of the reducing agent in tail gas in mixing tube 5 of other forms can be with structure Figure out.
By the mixing tube 5 of the application and the feature for the raising mixture homogeneity being arranged inside, reducing agent is in tail gas More uniformly mixed,
For the first cover 3, can be designed on the whole in tear drop shape, i.e., with oxidation catalyzer unit 1 Axially vertical plane in, the size at the position of the facing oxidation catalyzer unit 1 of the first cover 3 is greater than facing to mixing The position of the Upstream section 5a of pipe 5.This structure is made combustion gas and is flowed into mixing tube 5 with the speed being gradually increased from the first cover 3, To be conducive to shock of the tail gas in mixing tube 5 between reducing agent and mix.
It may be noted that the arrangement of scope of the present application covering diagram, i.e. oxidation catalyzer unit 1 and selective catalysis First end, that is, leading-in end of reduction unit 2 is located at the same side, and the second end, that is, output end of the two is located at the other side;However, this Shen Range please also covers following arrangements, i.e., the of the first end of oxidation catalyzer unit 1 and selective catalytic reduction unit 2 Two ends are located at the same side, and the second end of oxidation catalyzer unit 1 and the first end of selective catalytic reduction unit 2 are located at another Side.No matter which kind of arrangement, mixing tube 5 is all the second end and selective catalytic reduction unit 2 in oxidation catalyzer unit 1 First end between establish connection, and by the mixture of tail gas and reducing agent with cyclone mode introduce selective catalytic reduction unit In 2 first end.
According to the application, the mixed airflow of tail gas and reducing agent flows through selective catalysis also with more uniform temperature and speed Catalyst in prototype, to more efficiently remove the nitrogen oxides in tail gas.In addition, mixability of the reducing agent in tail gas It can be improved, this is also beneficial to the removal of the nitrogen oxides in tail gas.
In addition, reducing agent is atomized uniformly and rapidly and evaporates in mixing tube, therefore it can avoid former agent in mixing tube Crystallization, can also avoid the occurrence of the case where reducing agent drop encounters reducing agent matrix first end face in selective catalytic reduction device.
In addition, the exhaust gas aftertreatment system of the application has compact construction.This makes exhaust gas aftertreatment system be easy to full The exhaust emissions requirement of sufficient greater degree.
In addition, the exhaust gas aftertreatment system of the application is easy to manufacture and assembles, therefore cost can be reduced.
In addition, the exhaust gas aftertreatment system of the application has lower back pressure, so that tail gas flows through exhaust gas aftertreatment system Pressure drop afterwards is smaller.
Although describing the application herein with reference to specific embodiment, scope of the present application is not limited to shown Details.Without departing from the basic principle of the application, various modifications can be made for these details.

Claims (12)

1. a kind of box exhaust gas aftertreatment system, comprising:
Oxidation catalyzer unit (1) and selective catalytic reduction unit (2) arranged side by side respectively has first end and second End;
Mixing tube (5), Upstream section is connected to the second end of oxidation catalyzer unit (1), tract and selective catalytic reduction The first end of unit (2) is connected to;And
Reducing agent jet port (7) is installed on mixing tube (5), for being ejected into reducing agent jet flow through the oxidation catalyzer The second end of unit (1) enters in the tail gas of the mixing tube (5);
Wherein, the selective catalytic reduction unit (2) has first end cavity (2c), and the tract of mixing tube (5) is opened on The first end cavity (2c);
Flap (10) are equipped in the first end cavity (2c), the flap (10) is configured so that through mixing tube (5) Tract flows into the tail gas for being mixed with reducing agent in the first end cavity (2c) by the flap (10) guidance and with eddy flow Form flowing in the first end cavity (2c).
2. box exhaust gas aftertreatment system as described in claim 1, wherein the flap (10) is along selective catalysis The form of the arc section of shell (2a) arrangement of reduction unit (2), and there is upstream for the flow direction of tail gas Edge and downstream edge, the upstream edge are disposed adjacent to that side of the tract opening of mixing tube (5).
3. box exhaust gas aftertreatment system as claimed in claim 2, wherein the position of the upstream edge in the axial direction is located at Between catalyst (2b) in the tract opening and selective catalytic reduction unit (2) of mixing tube (5).
4. box exhaust gas aftertreatment system as claimed in claim 2 or claim 3, wherein the flap (10) is inclined or curved Bent, so that in the axial direction, the downstream edge of the flap (10) is than upstream edge closer to selective catalytic reduction unit (2) first end.
5. the box exhaust gas aftertreatment system as described in any one of claim 2 to 4, wherein be equipped with two or more altogether Along the circumferential direction successive flap (10);Preferably, if there are two valve flaps (10) substantially in a rotationally symmetrical arrangement each other.
6. box exhaust gas aftertreatment system as claimed in claim 5, wherein in the axial direction, for along the circumferential direction successive For two flaps, before that flap downstream edge than below mutually the upstream edge of that flap closer to selection The first end of property catalytic reduction unit (2).
7. the box exhaust gas aftertreatment system as described in any one of claim 2 to 6, wherein the flap (10) has The inner periphery extended between upstream edge and downstream edge and outer periphery, the outer periphery are connected to or urge adjacent to selectivity Change the inner wall of the shell (2a) of reduction unit (2), the outer periphery is preferably formed with flange.
8. the box exhaust gas aftertreatment system as described in any one of claims 1 to 7, wherein the upstream of the mixing tube (5) Section and the second end of oxidation catalyzer unit (1) are connected to public the first cover (3);First cover (3) it is facing The horizontal and vertical size at the position of oxidation catalyzer unit (1) second end is preferably greater than facing to mixing tube (5) Upstream section The position of (5a).
9. such as box exhaust gas aftertreatment system described in any item of the claim 1 to 8, wherein the mixing tube (5) is single Pipe fitting;Alternatively, the mixing tube (5) is made of the multiple pipeline sections being spliced together each other.
10. box exhaust gas aftertreatment system as claimed in any one of claims 1-9 wherein, wherein further include delivery pipe (6), institute The first end for stating delivery pipe (6) constitutes the discharge port (14) of box exhaust gas aftertreatment system, the second end of the delivery pipe (6) Public the second cover (4) is connected to the second end of the selective catalytic reduction unit (2).
11. the box exhaust gas aftertreatment system as described in any one of claims 1 to 10, wherein further include being sprayed in reducing agent Deflector (8) in mixing tube (5) is set at the position of loophole (7) upstream, formed in the deflector (8) multiple through-holes or Slit (84), for so that tail gas flows through each through-hole or slit (84) and forms multiply tail gas stream.
12. the box exhaust gas aftertreatment system as described in any one of claims 1 to 11, wherein further include in reducing agent meter It measures and hybrid element (9) is set in mixing tube (5) at the position in jet port (7) downstream, the hybrid element (9) has guidance also The fin (92) that former agent and tail gas along the circumferential direction deflect.
CN201710569429.6A 2017-07-13 2017-07-13 Box exhaust gas aftertreatment system Pending CN109252921A (en)

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