CN208816207U - A kind of diesel SCR catalytic exhaust apparatus - Google Patents

Abstract

The utility model relates to a kind of diesel SCR catalytic exhaust apparatus, including a urea nozzle for liquid, one section of exhaust mixing tube, one movement-oriented orifice plate, one noise elimination diffuser, at least one SCR catalyst unit, it is characterised in that: exhaust mixing tube is one section of exhaust pipe of above-mentioned SCR catalyst unit upstream, is divided into the first mixing chamber and the second mixing chamber by movement-oriented orifice plate；In local edge there are a flow channel, urea nozzle for liquid is mounted near the highest distance position of the first movement-oriented orifice plate of mixing indoor distances movement-oriented orifice plate, the spraying flow channel against movement-oriented orifice plate of the urea solution of ejection；The outlet of second mixing chamber is the entrance of noise elimination diffuser, is also at apart from flow channel compared with distant positions；The spray droplet that urea nozzle for liquid sprays evaporates mixing within an exhaust-gas stream, enter the second mixing chamber by the high-speed flow inside flow channel, noise elimination diffuser is entered back into, the relatively far path of an approximate broken line is flowed through, eventually forms homogeneous mixture and enter SCR catalyst unit.

Description

A kind of diesel SCR catalytic exhaust apparatus

Technical field

The utility model belongs to engine exhaust post-processing technology field, and in particular to engine exhaust selective reduction (SCR) reducing agent of technology and the mixing arrangement of engine exhaust and SCR catalytic exhaust gas device.

Background technique

With becoming increasingly conspicuous for environmental problem, energy-saving and emission-reduction have become the endless requirement of vehicle and engine, For this purpose, each state has all put into effect a series of vehicular emission standards, and it is increasingly stringenter.In this regard, using internal combustion engine as the vehicle of power Need to install discharge post-treatment system in the hope of meeting emission request.For example, being currently used primarily in in diesel motor exhaust SCR (Selective Catalytic Reduction) technology etc. that the pollutants such as NOx carry out catalytic treatment has become bavin The technology that oily vehicle etc. must use.

SCR technology needs reducing agent metered injection entering SCR catalysis turn into after mix with exhaust in diesel exhaust gas Parallel operation.Reducing agent has the aqueous solution of urea of 32.5% weight concentration (to be also diesel exhaust gas treatment fluid DEF=Diesel Exhaust Fluid perhaps adds blue liquid AdBlue) or ammonia.The ammonia that DEF is decomposited in exhaust by exhaust high temperature, Or the gaseous state ammonia directly ejected, SCR catalyst is entered after mixing with engine exhaust, under the effect of the catalyst, With the NOx etc. in engine exhaust catalytic reduction reaction will occur for ammonia, and NOx is made to be decomposed into harmless N₂、H₂O.If also Former reactant can not uniformly be mixed with exhaust, then ammonia will be very uneven with NOx ratio value (ammonia nitrogen ratio) in SCR catalyst Even, as a result partially catalyzed device unit might have extra ammonia leakage into tail gas, and partially catalyzed device unit in default of Ammonia and be difficult to that NOx is made effectively to be degraded.

On the other hand, after the DEF of liquid is ejected into the exhaust pipe of engine, if can not fast pyrogenation be ammonia and with row Gas be uniformly mixed, then probably due to other physicochemical changes and become solid-state junction crystal and remain in exhaust pipe, for a long time product It is tired to block the exhaust pipe of engine, make engine performance severe exacerbation.

Crystallization of the DEF in exhaust pipe, is influenced by many factors, most importantly temperature and two phase flow speed. Temperature determines chemical reaction product, and flowing velocity determines whether the solid-state junction crystal in product can be accumulated in inside pipeline.

Existing SCR technology will be such that the reactant sprayed is uniformly mixed with engine exhaust by every means, adopt thus SCR system is helped with the gas of compressed air atomized spray DEF, also the non-gas of reliable pressure injection atomization DEF helps SCR system, There is the solid-state ammonia SCR system of directly injection ammonia.But due to the limitation of structure snd size, accomplish the mixed uniformly side of absolute ideal Case is not present.General optimization method is by designing special mixing arrangement, and it is enough to allow reactant to mix with exhaust SCR catalyst unit is entered back into after the long time.Method by lengthening mixing length of tube, although the most simple and effective, this is given The arrangement of exhaust pipe onboard brings limitation, and exhaust pipe manufacturing cost also will increase.It is how real in exhaust pipe as short as possible Existing reactant is mixed with the quick of exhaust, must also especially be reduced crystallization risk of the DEF in exhaust pipe, just be become SCR One of the critical issue of system success application.

Summary of the invention

The utility model in view of the above-mentioned problems, be designed to provide one kind can reduce SCR catalytic exhaust gas silencer length, Crystallization risk in the exhaust pipe of engine is reduced, reactant is improved and is vented the SCR catalytic exhaust gas device of mixture homogeneity, simultaneously Reduce SCR system cost.

To achieve the above object, the utility model takes following technical scheme:

A kind of diesel SCR catalytic exhaust apparatus, including a urea nozzle for liquid, one section of exhaust mixing tube, a flowing Guide hole plate, a noise elimination diffuser, at least one SCR catalyst unit, it is characterised in that: exhaust mixing tube is that SCR catalysis is single One section of exhaust pipe of first upstream is divided into the first mixing chamber and the second mixing chamber, movement-oriented orifice plate by movement-oriented orifice plate In local edge there are a flow channel, urea nozzle for liquid is mounted on the farthest of the first movement-oriented orifice plate of mixing indoor distances Near position, the spraying flow channel against movement-oriented orifice plate of the urea solution of ejection；The outlet of second mixing chamber is to eliminate the noise to expand The entrance of separate tube, is also at apart from flow channel compared with distant positions；The spray droplet that urea nozzle for liquid sprays evaporates within an exhaust-gas stream Mixing enters the second mixing chamber by the high-speed flow inside flow channel, enters back into noise elimination diffuser, flows through an approximate folding The relatively far path of line eventually forms homogeneous mixture and enters SCR catalyst unit.

According to the above technical scheme, the DEF urea solution being vented in mixing tube is sprayed and the mixed path of engine exhaust, must It is so the broken line (serpentine) by repeatedly turning round, therefore path length is longer, is conducive to before reaching SCR catalyst, completely Evaporation is pyrolyzed and is uniformly mixed.On the other hand, the urea solution of ejection be sprayed at into guide hole plate flow channel nearby for the first time Colliding solid wall surface, but because the flow channel circulation area below guide hole plate is small, exhaust flow rate is big herein, therefore mixes To reinforcement, the drop for not evaporating pyrolysis is also difficult to be detained generation crystallization.DEF and exhaust mixed flow are in quickly mixing evaporation process It is middle to enter the second mixing chamber, because diffusion makes speed that can be lower, but can accelerate when flow direction eliminates the noise diffusion tube inlet, in addition to small again Outside the stagnation point at the turning of part, flowing is substantially smooth, therefore it is also smaller to generate a possibility that mass crystallization blocks runner.

After DEF is heated by engine exhaust, can dry out precipitated urea crystalline particle first, but if temperature is enough Height is higher than the gasification temperature of urea, is then not in urea crystals particle and is directly becoming gaseous state urea.High temperature urea and water Steam reaction will be pyrolyzed as ammonia and carbon dioxide.Meanwhile urea also will do it other chemical reactions, generate biuret, three The crystalline solid such as paracyanogen acid, but the speed of these reactions is slower than the speed that urea pyrolysis is ammonia, does not contact in DEF compared with low temperature When spending solid wall surface, crystalline solid will not be accumulated.When two-phase flow speed is sufficiently large, crystalline solid can be with exhaust stream being formed It walks, will not accumulate.

Following technical solution, is further limited the utility model or optimizes.

Optionally, during the urea that urea nozzle for liquid sprays is spraying, the spraying direction of motion of bump flow guide hole plate with The angle of movement-oriented orifice plate normal is greater than 30 °.

Optionally, during the urea that urea nozzle for liquid sprays is spraying, the SPRAY MOTION direction of collision exhaust mixing tube wall surface with The angle of exhaust mixing tube wall normal is greater than 30 °.

Optionally, movement-oriented orifice plate inclination is fixed on exhaust mixing tube wall, farthest away from the orifice plate portion of flow channel Divide the axis direction along exhaust mixing tube nearest apart from urea nozzle for liquid.

Optionally, the ratio between the cross-sectional area of the gross area of flow channel and exhaust mixing tube, less than 50%.

Optionally, the flow channel of movement-oriented orifice plate, it is tangential including being made of more than two tangential guide vanes Runner makes the air-flow for flowing through the channel form the rotating flow around exhaust mixing tube axis in the second mixing chamber.

Optionally, tangential guide vane is structure as a whole with movement-oriented orifice plate, punch forming.

Optionally, movement-oriented orifice plate is relatively distant from the position of flow channel, also is provided with 2 or more tangential guide vanes Auxiliary swirl channel is formed, assists the circulation area of swirl channel to be less than the 50% of the circulation area of slipstream, the rotation of formation Flow direction and the incision in lower flow channel to be oriented to blade-shaped at eddy flow steering it is identical.

Optionally, tangential guide vane is all into a single integrated structure with movement-oriented orifice plate up and down, punch forming.

Optionally, movement-oriented orifice plate is made of a foreboard and a backboard, and backboard is placed in parallel with foreboard, therebetween shape At secondary flow-guiding channel, secondary flow-guiding channel entrance is the subaisle opening for being located at foreboard top, and secondary flow-guiding channel outlet is backboard Lower-most edge, flow-guiding channel 5mm or more of the lower-most edge apart from foreboard lower part, flowing in secondary flow-guiding channel by up to Under, urea is spraying not to enter secondary flow-guiding channel.

Optionally, backboard lower edge portion is bent to foreboard, forms the non-uniform secondary flow-guiding channel of circulation area size Outlet, two corner parts opening in the outlet of secondary flow-guiding channel is big, and intermediate position opening is small.

Optionally, deflector is arranged in the second mixing chamber end and noise elimination diffuser intersection.

Optionally, deflector upper end is fixed on noise elimination diffuser drive end bearing bracket, and deflector upper end-face edge is apart from noise elimination diffuser Lower end distance is less than 5mm, and deflector lower end is fixed on the second mixing chamber lower end exhaust mixing tube.

Optionally, deflector and noise elimination diffuser axis angle are less than 45 °.

Optionally, the axial distance between the drive end bearing bracket of noise elimination diffuser and deflector lower end be less than movement-oriented orifice plate with 50% of axial distance between noise elimination diffuser.

The beneficial effects of the utility model are:

It reduces crystallization risk in the exhaust pipe of engine, improve reactant and exhaust mixture homogeneity, while can reduce SCR System cost.

Detailed description of the invention

Fig. 1 is the cross-sectional view of the utility model first embodiment.

Fig. 2 is the structural schematic diagram of the utility model first embodiment.

Fig. 3 is a kind of structural schematic diagram of movement-oriented orifice plate of the utility model first embodiment.

Fig. 4 is a kind of structural schematic diagram of movement-oriented orifice plate of the utility model second embodiment.

Fig. 5 is the side view of the movement-oriented orifice plate of the utility model second embodiment.

Fig. 6 is the structural schematic diagram of the movement-oriented orifice plate of the utility model 3rd embodiment.

Fig. 7 is the cross-sectional view of the movement-oriented orifice plate of the utility model 3rd embodiment.

In figure: 11 for exhaust mixing tube, 12 be urea nozzle for liquid, 13 be the first mixing chamber, 14 be movement-oriented orifice plate, 15 It is the second mixing chamber for flow channel, 16,17 be deflector, and 18 be noise elimination diffuser, and 19 be SCR catalyst unit.

21 be urea jet stream, during 22 urea that spray for urea nozzle for liquid are spraying, collides being sprayed for the exhaust mixing tube Incidence angle (mix the angle of tube wall normal with exhaust), 23 are sprayed for the urea that urea nozzle for liquid sprays, described in collision The spraying incidence angle (angle with movement-oriented orifice plate normal) of movement-oriented orifice plate, 24 be deflector and noise elimination diffuser axis Wire clamp angle.

31 be upper tangential guide vane, and 32 be incision to guide vane, and 33 be tangential runner, and 34 be auxiliary swirl channel.

41 be foreboard, and 42 be secondary flow-guiding channel entrance, and 43 be backboard, and 44 be secondary flow-guiding channel outlet.

Specific embodiment

The utility model is further described with reference to the accompanying drawings and examples.

It is as Figure 1-Figure 2: the first embodiment of the diesel SCR catalytic exhaust apparatus of the utility model, including one Urea nozzle for liquid 12, an exhaust mixing tube 11, a movement-oriented orifice plate 14.Mixing tube 11 is vented by movement-oriented orifice plate 14 It is divided into the first mixing chamber 13 and the second mixing chamber 16.

Urea nozzle for liquid 12 is mounted in the first mixing chamber 13, and the urea solution that urea nozzle for liquid 12 sprays is spraying against flowing Guide hole plate 14 and flow channel 15, urea solution spray droplet evaporates mixing in motor exhaust air-flow, by flow channel High-speed flow inside 15 enters the second mixing chamber 16, further evaporation mixing.

During the urea that urea nozzle for liquid 12 sprays is spraying, the spraying incidence angle 23 of bump flow guide hole plate 14 is (with stream The angle of 14 normal of action-oriented orifice plate) it is greater than 30 °.During the urea that urea nozzle for liquid 12 sprays is spraying, collision exhaust mixing tube 11 Spraying incidence angle 22 (angle with exhaust 11 tube wall normal of mixing tube) be greater than 30 °.

Movement-oriented orifice plate 14 on exhaust 11 tube wall of mixing tube fix at a certain angle by range.Positioned at urea nozzle for liquid 12 The movement-oriented orifice plate 14 of side is in the axis direction for being vented mixing tube 11, compared with lower flow channel 15, apart from urea solution The position of nozzle 12 is closer.That is the size L1 in Fig. 2 is less than L2.

17 front end of guide plate is arranged in 16 end of the second mixing chamber, and upper end is fixed on the drive end bearing bracket of noise elimination diffuser 18, leads 17 upper end-face edge of flowing plate is less than 5mm apart from 18 lower end of noise elimination diffuser distance, and 17 lower end of deflector is fixed on the second mixing chamber 16 On the exhaust mixing tube 11 of lower end, deflector 17 and 18 axis angle of noise elimination diffuser are less than 45 °.17 lower end of deflector with disappear The axial distance of 18 drive end bearing bracket of sound diffusion pipe is less than movement-oriented orifice plate 14 and the 50% of 18 axial distance of noise elimination diffuser.

As shown in figure 3, it is partition wall wall surface that movement-oriented orifice plate 14 is most of, only in part, there are flow channels 15.Flowing The gross area of the flow channel 15 of guide hole plate 14 and the ratio between the cross-sectional area of exhaust mixing tube 11, less than 50%.

In the utility model first embodiment, the urea solution that urea nozzle for liquid 12 sprays is spraying, will be along exhaust airstream Oblique to flow to flow channel 15, air-flow and mixing evaporation rate can gradually be accelerated, be reached by mixing velocity when flow channel 15 Then one peak value changes entrance of the flow direction towards noise elimination diffuser 18, further mixing is steamed into the second mixing chamber 15 Hair, forms uniform gaseous mixture using noise elimination diffuser 18 and enters SCR catalyst unit 19.Broken line glide path increases mixing Forwarding time simultaneously repeatedly enhances mixing velocity, to ensure that finally enter SCR catalyst is that urea solution is pyrolyzed to be formed The homogeneous mixture of ammonia and engine exhaust.

Meanwhile urea solution is spraying and is vented the collision angle of mixing tube solid wall surface always along flow direction of exhaust gases, protects The movement velocity for having demonstrate,proved spray droplet reduces the accumulative risk in the urea crystals object in region of being rebuffed.

The movement-oriented orifice plate 14 of the utility model can also as shown in fig. 4-5, to form the utility model second Embodiment.In second embodiment, movement-oriented orifice plate 14 includes upper tangential guide vane 31 and incision to guide vane 32, on Tangential guide vane 31 forms auxiliary swirl channel, and incision is to guiding blade-shaped tangentially runner 33.Assist swirl channel 34 Circulation area is less than the 50% of the circulation area of tangential runner 33, in the rotating flow direction of formation and lower flow channel 15 under The eddy flow that tangential guide vane 32 is formed turns to identical.

The circumferential flow around exhaust pipe axis can be generated into the exhaust stream of the second mixing chamber in this way, makes the mixing road of exhaust Diameter further lengthens, and mixing intensity also further strengthens.

The movement-oriented orifice plate 14 of the utility model can also be as Figure 6-Figure 7, to form the utility model third Embodiment.In 3rd embodiment, movement-oriented orifice plate 14 is made of a foreboard 41 and a backboard 43, backboard 43 and foreboard 41 It is placed in parallel, forms secondary flow-guiding channel between backboard 43 and foreboard 41, secondary flow-guiding channel entrance 42 is to be located at 41 top of foreboard Subaisle opening, secondary flow-guiding channel outlet 44 are the lower-most edge of backboard 43, and lower-most edge is led apart from 41 lower part of foreboard Circulation road 15 has the distance of 5mm or more, and from top to bottom, urea is spraying not to enter secondary flow-guiding channel to the flowing in secondary flow-guiding channel. 43 lower edge portion of backboard is bent to foreboard 41, the non-uniform secondary flow-guiding channel outlet 44 of circulation area size is formed, in pair Two corner parts opening of flow-guiding channel outlet 44 is big, and intermediate position opening is small.

In this way, forming the exhaust stream of secondary flow-guiding channel outflow between backboard 43 and foreboard 41, it will be able to before constantly flowing through The marginal portion for the flow channel 15 that plate 41 is constituted, to guarantee not evaporating by spraying containing urea by flow channel 15 The drop of completion will not be trapped on foreboard 41 because of vortex and for a long time, reduce the wind for occurring urea crystals accumulation herein Danger.

The application method of the utility model is as follows:

Automatically controlled DCU (not shown) controls urea nozzle for liquid 12 according to the data of NO sensor and temperature sensor The amount of injection.

After urea nozzle for liquid 12 ejects aqueous solution of urea, reactant gradually adds under the action of motor exhaust air-flow Speed, because the gross area of the flow channel 15 of movement-oriented orifice plate 14 and the ratio between the cross-sectional area of exhaust mixing tube 11 are less than 50%, so the speed highest of reactant here.

Movement-oriented orifice plate provided by the embodiment of the utility model includes at least following 2 kinds of embodiments:

In one case, when movement-oriented orifice plate 14 is structure as shown in Figure 4, reactant passes through flow channel 15 When, the effect by incision to guide vane 32 is formed into tangential runner 33 in the second mixing chamber 16 around exhaust mixing tube 11 The rotating flow of axis.

Motor exhaust has portion gas by upper tangential guide vane 31, is formed by auxiliary swirl channel 34 around row The rotating flow of 11 axis of gas mixing tube, incision is to guiding in the rotating flow direction and lower flow channel 15 that accessory channel 34 is formed The eddy flow that blade is formed turns to identical.

It assists the circulation area of swirl channel 34 to be less than the 50% of the circulation area of tangential runner 33, enters second in gas Undecomposed DEF liquid reactant is further mixed with top engine gas eddy flow in 16 rear lower eddy flow of mixing chamber, mixing Gas is similar to broken line in the motion path of the second mixing chamber 16.

In another case, when movement-oriented orifice plate 14 is structure as shown in FIG. 6, reactant passes through movement-oriented Enter the second mixing chamber 16 after the flow channel 15 of orifice plate 14, because the cross-sectional area of the second mixing chamber 16 is far longer than flowing The cross-sectional area in channel 15, reactant flow velocity sharp fall, and there are also be not decomposed into ammonia much for DEF liquid reactant. DEF liquid reactant is under the action of air-flow simultaneously, with relatively low movement-oriented 14 back wall of orifice plate of velocity collision.Excessive DEF necessarily generates strong cooling to movement-oriented 14 back wall of orifice plate, causes local temperature relatively low, and DEF pyrolysis is the speed of ammonia Degree is greatly reduced, and the chemical time for forming crystalline material will be very long, and because movement-oriented 14 back wall of orifice plate flows Speed is very low, and crystalline particle object is just difficult to be blown away by air-flow.So if without other special designings, in movement-oriented orifice plate 14 back walls are readily formed crystallization.

Motor exhaust has portion gas to enter in secondary flow-guiding channel by secondary flow-guiding channel entrance 42, and then air-flow is by upper And lower flow at high speed, the air-flow can heat movement-oriented 14 back wall of orifice plate, and can accelerate the air velocity at this, be greatly lowered The probability of crystallization.Then air-flow enters the second mixing in the air-flow of 44 outflow of secondary flow-guiding channel outlet and flow channel 15 together Room 16.

18 offset placement of noise elimination diffuser, flows gas in mixing chamber with broken line, if without other special designings, Gas backstreaming is easy to produce on 18 drive end bearing bracket capping of noise elimination diffuser.The guide plate 17 that 16 end of the second mixing chamber is arranged in is straight It connects guidance air-flow and enters noise elimination diffuser 18, the flowing velocity of gas will not be greatly reduced, and extend incorporation time, reduce crystallization wind Danger.

Without departing from the utility model principle, made any modification, the alternatives such as simplified are included in Within protection scope of the present invention.

The parts not involved in the utility model is same as the prior art or can be realized by using the prior art.

Claims (15)

1. a kind of diesel SCR catalytic exhaust apparatus, including a urea nozzle for liquid (12), one section of exhaust mixing tube (11), one A movement-oriented orifice plate (14), a noise elimination diffuser (18), at least one SCR catalyst unit (19), it is characterised in that: described It is vented one section of exhaust pipe that mixing tube (11) are above-mentioned SCR catalyst unit (19) upstream, by the movement-oriented orifice plate (14) It is divided into the first mixing chamber (13) and the second mixing chamber (16)；There are a streams in local edge for the movement-oriented orifice plate (14) Dynamic channel (15), the urea nozzle for liquid (12) are mounted on movement-oriented orifice plate (14) described in the first mixing chamber (13) interior distance Near highest distance position, the spraying flow channel (15) against the movement-oriented orifice plate (14) of the urea solution of ejection；Second mixing The outlet of room (16) is the entrance of noise elimination diffuser (18), is also at apart from flow channel (15) compared with distant positions；Urea nozzle for liquid (12) spray droplet sprayed evaporates mixing within an exhaust-gas stream, and it is mixed to enter second by the internal high-speed flow of flow channel (15) Close room (16), enter back into noise elimination diffuser (18), flow through the relatively far path of an approximate broken line, eventually form homogeneous mixture into Enter SCR catalyst unit (19).

2. diesel SCR catalytic exhaust apparatus as described in claim 1, it is characterised in that: urea nozzle for liquid (12) spray During urea out is spraying, the spraying direction of motion and movement-oriented orifice plate (14) normal of the movement-oriented orifice plate (14) are collided Angle be greater than 30 °.

3. diesel SCR catalytic exhaust apparatus as claimed in claim 2, it is characterised in that: urea nozzle for liquid (12) spray During urea out is spraying, SPRAY MOTION direction and exhaust mixing tube (11) tube wall method of described exhaust mixing tube (11) wall surface are collided The angle of line is greater than 30 °.

4. diesel SCR catalytic exhaust apparatus as described in claim 1, it is characterised in that: the movement-oriented orifice plate (14) It is fixed on exhaust mixing tube (11) tube wall with scheduled tilt angle, farthest away from the aperture plate portion edge of flow channel (15) The axis direction of exhaust mixing tube (11) is nearest apart from urea nozzle for liquid (12).

5. the diesel SCR catalytic exhaust apparatus as described in claim 3 or 4, it is characterised in that: the flow channel (15) the ratio between the cross-sectional area of the gross area and exhaust mixing tube (11), less than 50%.

6. diesel SCR catalytic exhaust apparatus as claimed in claim 5, it is characterised in that: the movement-oriented orifice plate (14) Flow channel (15) make the air-flow for flowing through the channel including the tangential runner being made of more than two tangential guide vanes The rotating flow around exhaust mixing tube (11) axis is formed in the second mixing chamber (16).

7. diesel SCR catalytic exhaust apparatus as claimed in claim 6, it is characterised in that: the tangential guide vane and stream Action-oriented orifice plate (14) is structure as a whole, punch forming.

8. diesel SCR catalytic exhaust apparatus as claimed in claim 7, it is characterised in that: in movement-oriented orifice plate (14) phase Auxiliary swirl channel (34) is formed to 2 or more tangential guide vanes (31) on the position far from flow channel (15), also are provided with, Assist swirl channel (34) circulation area be less than tangential runner (33) circulation area 50%, the rotating flow direction of formation with The eddy flow that incision in lower flow channel (15) is formed to guide vane (32) turns to identical.

9. diesel SCR catalytic exhaust apparatus as claimed in claim 8, it is characterised in that: up and down tangential guide vane all with Movement-oriented orifice plate (14) is into a single integrated structure, punch forming.

10. diesel SCR catalytic exhaust apparatus as claimed in claim 3, it is characterised in that: the movement-oriented orifice plate (14) it is made of a foreboard (41) and a backboard (43), backboard (43) is placed in parallel with foreboard (41), is formed pair therebetween and is led Circulation road, the pair flow-guiding channel entrance (42) are the subaisle opening for being located at foreboard (41) top, secondary flow-guiding channel outlet It (44) is the lower-most edge of backboard (43), flow channel (15) 5mm or more of lower-most edge apart from foreboard (41) lower part, institute State flowing in secondary flow-guiding channel from top to bottom, urea is spraying not to enter secondary flow-guiding channel.

11. diesel SCR catalytic exhaust apparatus as claimed in claim 10, it is characterised in that: backboard (43) lower edge Edge point is bent to the foreboard (41), the non-uniform secondary flow-guiding channel outlet (44) of circulation area size is formed, in secondary water conservancy diversion Two corner parts opening of channel outlet (44) is big, and intermediate position opening is small.

12. diesel SCR catalytic exhaust apparatus as described in claim 1, it is characterised in that: the end of the second mixing chamber (16) Deflector (17) are set with noise elimination diffuser (18) intersection.

13. diesel SCR catalytic exhaust apparatus as claimed in claim 12, it is characterised in that: deflector (17) upper end is fixed On noise elimination diffuser (18) drive end bearing bracket, deflector (17) upper end-face edge is less than 5mm at a distance from noise elimination diffuser (18) lower end, Deflector (17) lower end is fixed on the exhaust mixing tube (11) below the second mixing chamber (16).

14. diesel SCR catalytic exhaust apparatus as claimed in claim 13, it is characterised in that: the axis of noise elimination diffuser (18) Angle between line and deflector (17) is less than 45 °.

15. diesel SCR catalytic exhaust apparatus as claimed in claim 14, it is characterised in that: before noise elimination diffuser (18) Axial distance between end cap and deflector (17) lower end is less than between movement-oriented orifice plate (14) and noise elimination diffuser (18) The 50% of axial distance.