SDPF tight coupling urea mixing device

Abstract

The invention provides an SDPF tight coupling urea mixing device which comprises a mixing pipe, and the mixing pipe comprises a hump pipe which comprises a first straight pipe section, a hump section and a second straight pipe section which are connected in sequence; the stretching end cover comprises a first annular piece and a blocking piece, the upstream end of the first annular piece is connected to the inner surface of the first straight pipe section in a sealed mode, the blocking piece is arranged at the downstream end of the first annular piece and partially blocks the first annular piece, and the groove in the inner side of the hump section is covered with the outer surface of the first annular piece; the crushing plate is arranged on the inner surface of the first straight pipe section and located on the upstream of the stretching end cover; the connecting pipe is connected to the second straight pipe section in a sleeving mode, and the downstream end of the connecting pipe is connected to the upstream end of the first air outlet pipe. The device is not only suitable for compact boundary arrangement in an engine compartment, but also convenient to install and maintain, and urea crystals on the surfaces of parts in the mixing pipe can be cleaned in time.

Description

Technical Field

[0001] The invention relates to the technical field of diesel engine exhaust aftertreatment, in particular to a SDPF tightly coupled urea mixing device. Background Art

[0002] In the diesel engine exhaust after-treatment system, the selective catalytic reduction technology (SCR) is usually used to reduce the NOx content in the exhaust gas. The selective catalytic reduction technology is to spray urea aqueous solution into the exhaust after-treatment mixer. Under the action of the catalyst, the nitrogen oxides in the exhaust gas will be reduced to harmless nitrogen and water, thereby achieving the purpose of reducing emissions.

[0003] SDPF is a post-treatment route that applies the SCR catalyst coating to the DPF to achieve a dual-layer function. It is currently mainly used in the post-treatment system of light diesel vehicles. SDPF must meet the higher NH3 mixing uniformity requirements of the SCR system to improve the NOx conversion efficiency, and also meet the high flow rate uniformity requirements of the DPF system to reduce the risk of soot blockage. Light diesel vehicles generally use a tightly coupled post-processor layout. Since the post-processor is installed in the engine compartment, the layout space is compact and the design of the mixing device is difficult.

[0004] In some products, especially the SDPF solution, the mixing device is connected to the DOC in front and to the SDPF in the back. Since the SDPF needs to be disassembled for maintenance, the SDPF and DOC sections must be detachable. The conventional solution is to design a detachable connection structure at the connection between the outlet end of the mixing device and the SDPF, but this connection structure occupies a large space and is not suitable for compact layout boundaries. It is also difficult to clean urea crystals on the surface of some parts in the mixing device. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a SDPF tightly coupled urea mixing device, which improves the structure of the mixing tube in the mixing device and changes the disassembly position of the mixing device, which is not only suitable for compact boundary arrangement in the engine compartment, but also convenient for installation and maintenance of the mixing device, and is conducive to timely cleaning of urea crystals on the surface of components in the mixing tube. The technical solution adopted by the present invention is: A SDPF tightly coupled urea mixing device comprises an intake pipe, a mixing pipe and a first outlet pipe connected in sequence, wherein the intake pipe is used to install a urea nozzle, and the mixing pipe comprises: A hump pipe, comprising a first straight pipe section, a hump section and a second straight pipe section connected in sequence, wherein the upstream end of the first straight pipe section is connected to the downstream end of the air inlet pipe; A stretching end cover, comprising a first annular sheet and a blocking sheet, wherein the upstream end of the first annular sheet is sealingly connected to the inner surface of the first straight pipe section, and the blocking sheet is arranged at the downstream end of the first annular sheet to partially block the first annular sheet, wherein the outer surface of the first annular sheet covers the groove inside the hump section; A crushing plate, arranged on the inner surface of the first straight pipe section and located upstream of the stretching end cover; A clamp and a connecting pipe, wherein the connecting pipe is sleeved on the second straight pipe section, the downstream end of the connecting pipe is connected to the upstream end of the first air outlet pipe, and the connecting pipe is tightly matched with the hump section through the clamp.

[0006] Further, the inner diameter of the first straight pipe section, the inner diameter of the second straight pipe section and the outer diameter of the first annular sheet are the same; or, The inner diameter of the first straight pipe section is greater than the inner diameter of the second straight pipe section, and part of the outer diameter of the first annular sheet shrinks toward its downstream end to form a tapered section, and the outer surface of the tapered section is tightly matched with the inner surface of the second straight pipe section.

[0007] Further, the blocking piece partially covers the downstream end of the first annular piece, so that a third airflow adjustment hole is formed between the edge of the blocking piece and the inner surface of the first annular piece.

[0008] Further, the baffle completely covers the downstream end of the first annular sheet; or, the baffle is penetrated by a first airflow adjustment hole and / or a second airflow adjustment hole.

[0009] Furthermore, the connecting pipe includes a third straight pipe section and a flange section, the third straight pipe section is sleeved on the outer surface of the second straight pipe section, the flange section extends along the outer surface of the hump section, and the clamp clamps the flange section and the hump section.

[0010] Furthermore, a sealing gasket is provided between the flange section and the hump section.

[0011] Furthermore, the crushing plate includes a second annular plate and a crushing plate, the second annular plate is sealed and connected to the inner surface of the first straight pipe section, and the crushing plate forms a first flip blade and a second flip blade toward the downstream of the hump pipe, and the first flip blade and the second flip blade have different flip directions.

[0012] Furthermore, a spoiler is provided inside the intake pipe, and the spoiler divides the intake pipe into an intake chamber and a mixing chamber connected upstream and downstream. A nozzle base is provided on one side of the mixing chamber on the intake pipe, and the nozzle base is used to install a urea nozzle.

[0013] Further, a mixing plate is provided at the downstream end of the first air outlet pipe, the mixing plate is provided with a first mixing hole and / or a second mixing hole, and the axis of the mixing plate is eccentrically arranged relative to the axis of the nozzle base.

[0014] Furthermore, a second air outlet pipe is provided at the downstream end of the first air outlet pipe.

[0015] Advantages of the present invention: The present invention forms a modular structure through a mixing tube, realizes the detachable connection between the mixing device and its downstream SDPF, transfers the connection point from the end of the mixing device to the middle thereof, and avoids the problem of the compact boundary arrangement in the engine compartment interfering with the installation of the mixing device without changing the mixing space of the mixer. The present invention uses a detachable mixing tube to directly expose the crushing plate and the stretching end cover, making it more convenient to clean the urea crystals on the surface thereof; The present invention completely blocks the groove inside the hump tube by the cooperation between the hump tube and the stretch end cover, thereby preventing urea crystals from forming in the groove of the hump tube. The present invention utilizes the baffle structure in the stretch end cover to adjust the back pressure and the ammonia mixing uniformity of the mixing device; The present invention uses a spoiler to interfere with the airflow entering the mixing device, thereby preventing the exhaust airflow from directly blowing the urea solution to cause urea crystallization; The present invention increases the urea evaporation area through the crushing plate and the baffle, increases the pyrolysis efficiency of the urea aqueous solution, improves the ammonia mixing uniformity of the mixing device, and adjusts the back pressure of the mixing device; The present invention improves the uniformity of the airflow at the outlet end of the mixing device through the mixing plate, thereby improving the mixing uniformity of the mixing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a cross-sectional view from the first viewing angle of the present invention.

[0017] Figure 2 This is a cross-sectional view from a second viewing angle of the present invention.

[0018] Figure 3 Schematic diagram of the mixing tube assembly.

[0019] Figure 4 This is an exploded view of the mixing tube.

[0020] Figure 5 This is the exhaust airflow path diagram from the first perspective.

[0021] Figure 6 This is the exhaust airflow path diagram from the second perspective.

[0022] In the figure: 100-intake pipe, 110-nozzle base, 120-intake chamber, 130-mixing chamber, 200-mixing tube, 210-hump tube, 211-first straight pipe section, 212-hump section, 213-second straight pipe section, 220-stretching end cover, 221-first annular sheet, 221a-conical section, 221b-extension section, 222-blocking sheet, 223-first airflow adjustment hole, 224-second airflow adjustment hole, 225-third airflow Adjusting hole, 230-crushing plate, 231-second annular plate, 232-crushing plate, 233-first flip blade, 234-second flip blade, 240-hoop, 250-connecting pipe, 251-third straight pipe section, 252-flanged section, 260-sealing gasket, 300-first air outlet pipe, 400-mixing plate, 410-first mixing hole, 420-second mixing hole, 500-spoiler plate, 510-spoiler hole, 600-second air outlet pipe. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] Please see attached Figure 1-4 The present invention provides a SDPF tightly coupled urea mixing device, comprising an intake pipe 100, a mixing pipe 200 and a first outlet pipe 300 connected in sequence, wherein the intake pipe 100 is used to install a urea nozzle, and the mixing pipe 200 comprises: a hump pipe 210, comprising a first straight pipe section 211, a hump section 212 and a second straight pipe section 213 connected in sequence, wherein the upstream end of the first straight pipe section 211 is connected to the downstream end of the intake pipe 100; a stretching end cover 220, comprising a first annular sheet 221 and a blocking sheet 222, wherein the upstream end of the first annular sheet 221 is sealed and connected to the inner surface of the first straight pipe section 211, The baffle 222 is arranged at the downstream end of the first annular plate 221 to partially block the first annular plate 221, wherein the outer surface of the first annular plate 221 covers the groove on the inner side of the hump section 212; the crushing plate 230 is arranged on the inner surface of the first straight pipe section 211 and is located upstream of the stretching end cover 220; the clamp 240 and the connecting pipe 250, the connecting pipe 250 is sleeved on the second straight pipe section 213, the downstream end of the connecting pipe 250 is connected to the upstream end of the first air outlet pipe 300, and the connecting pipe 250 is tightly fitted with the hump section 212 through the clamp 240.

[0025] In the present invention, the upstream end of the air inlet pipe 100 is connected to the DOC, and the downstream end of the first air outlet pipe 300 is connected to the SDPF. Through the improved structure of the mixing device, a detachable clamp is designed on the mixing tube 200, and the detachable connection between the SDPF and the DOC is realized without affecting the mixing space of the mixing device. In particular, when the detachable position is on the mixing tube 200, the connecting tube 250 and the hump tube 210 are separated by removing the clamp 240, and the stretching end cover 220 and the crushing plate 230 are directly exposed, so that the urea crystals inside the mixing tube 200 are conveniently cleaned.

[0026] Secondly, due to the structural coordination between the hump tube 210 and the clamp 240, the groove inside the hump section 212 usually accumulates urea crystals in the groove due to the small exhaust airflow, causing product failure. Therefore, by setting a stretchable stretching end cover 220 so that its stretching length is greater than the groove width, the windward surface of the first annular sheet 221 of the stretching end cover 220 is connected to the inner surface of the first straight pipe section 211, and the leeward surface of the first annular sheet 221 (i.e., the back of the baffle 222) is tightly fitted with the inner surface of the second straight pipe section 213, the groove is completely blocked and sealed, and urea crystals are prevented from appearing in the groove, thereby affecting product quality.

[0027] In one embodiment, as shown in the attached Figure 2 and Figure 3 As shown, the upstream end of the first straight pipe section 211 is welded and fixed to the downstream end of the inlet pipe 100, and the downstream end of the connecting pipe 250 is welded and fixed to the upstream end of the first outlet pipe 300. The welding fixation method is used to ensure the structural strength of the outside of the mixing device, shorten the overall volume and length of the mixing device, and realize the tight coupling of the device.

[0028] In one embodiment, as shown in the attached Figure 3 As shown, the upstream end of the first annular sheet 221 is welded and fixed to the inner surface of the first straight pipe section 211, and the stretched end cover 220 and the hump pipe 210 are formed into a whole by the welding fixation method to prevent the stretched end cover 220 from falling off under the action of the exhaust pressure; in this embodiment, a plurality of extension sections 221b can be added to the windward surface of the first annular sheet 221 to increase the contact area between the first annular sheet 221 and the first straight pipe section 211, and at the same time, the welding points can be increased to improve the connection strength between the first annular sheet 221 and the hump pipe 210.

[0029] In a specific embodiment, the inner diameter of the first straight pipe section 211, the inner diameter of the second straight pipe section 213 and the outer diameter of the first annular sheet 221 are the same; when the three diameters are the same, the second straight pipe section 213 and the first annular sheet 221 can be transitionally fitted or interference fit.

[0030] In another specific embodiment, as shown in the attached Figure 3As shown, the inner diameter of the first straight pipe section 211 is larger than the inner diameter of the second straight pipe section 213, and part of the outer diameter of the first annular sheet 221 shrinks toward its downstream end to form a tapered section 221a, and the outer surface of the tapered section 221a is tightly matched with the inner surface of the second straight pipe section 213. Under this condition, when assembling the hump pipe 210 and the stretching end cover 220, the problem of reverse installation of the stretching end cover 220 can be avoided; the stretching end cover 220 can only extend from the first straight pipe section 211 to the second straight pipe section 213 until the tapered section 221a is stuck on the inner surface of the second straight pipe section 213, and then the stretching end cover 220 is welded and fixed.

[0031] For easy understanding, please refer to the attached Figure 3 and Figure 4 Since the baffle 222 partially blocks the first annular plate 221, the mixed gas can flow through the channel between the baffle 222 and the first annular plate 221, and the back pressure is adjusted by changing the size of the flow channel.

[0032] In one embodiment, the baffle 222 partially covers the downstream end of the first annular plate 221, so that a third airflow adjustment hole 225 is formed between the edge of the baffle 222 and the inner surface of the first annular plate 221; the third airflow adjustment hole 225 serves as a flow channel for the mixed gas, and can adjust the back pressure and the ammonia mixing uniformity of the mixing device; in this embodiment, the shape of the third airflow adjustment hole 225 is set as needed, including but not limited to a circular hole, a waist hole, a square hole, and an irregular hole.

[0033] In a specific embodiment, the blocking sheet 222 completely covers the downstream end of the first annular sheet 221 ; under this condition, the back pressure can only be adjusted by changing the size of the third airflow adjustment hole 225 .

[0034] In a specific embodiment, the baffle 222 is provided with a first airflow adjustment hole 223 and / or a second airflow adjustment hole 224; by adding one or more first airflow adjustment holes 223 and / or second airflow adjustment holes 224, the size of the flow channel can be further increased or decreased to adjust the back pressure. In this embodiment, the shapes of the first airflow adjustment hole 223 and the second airflow adjustment hole 224 are set as required, including but not limited to a circular hole, a waist hole, a square hole, and a special-shaped hole.

[0035] As attached Figure 3As shown, it should be noted that the connecting pipe 250 includes a third straight pipe section 251 and a flange section 252, the third straight pipe section 251 is sleeved on the outer surface of the second straight pipe section 213, the flange section 252 extends along the outer surface of the hump section 212, and the clamp 240 clamps the flange section 252 and the hump section 212. The flange section 252 increases the contact area between the connecting pipe 250 and the hump pipe 210 and the clamp 240, which can improve the tightening effect of the clamp, and at the same time, the connection between the second straight pipe section 213 and the third straight pipe section 251 is located downstream of the connection between the flange section 252 and the hump section 212, so that the exhaust gas flow will not flow back to the connection between the flange section 252 and the hump section 212, thereby preventing the leakage of the mixed gas.

[0036] In a specific embodiment, in order to further improve the sealing performance of the connection between the connecting pipe 250 and the second straight pipe section 213 , a sealing gasket 260 is provided between the flange section 252 and the hump section 212 .

[0037] In one embodiment, as shown in the attached Figure 3 and attached Figure 4 As shown, the crushing plate 230 includes a second annular sheet 231 and a crushing sheet 232, wherein the second annular sheet 231 is sealed and connected to the inner surface of the first straight pipe section 211, and the crushing sheet 232 forms a first flip blade 233 and a second flip blade 234 toward the downstream of the hump pipe 210, and the flip directions of the first flip blade 233 and the second flip blade 234 are different. The flip blades with different flip directions increase the urea evaporation area and the efficiency of pyrolysis of urea aqueous solution, thereby improving the uniformity of ammonia mixing in the mixing device and reducing the crystallization risk of the mixing device. The mixed gas crushed by the crushing sheet 232 passes through different airflow adjustment holes of the stretching end cover 220 to adjust the back pressure, further improving the uniformity of ammonia mixing.

[0038] In this application, if attached Figure 5 and attached Figure 6As shown, in order to achieve sufficient mixing of the urea solution and the exhaust gas flow in the mixing device, a spoiler 500 is provided inside the intake pipe 100, and the spoiler 500 divides the intake pipe 100 into an intake chamber 120 and a mixing chamber 130 connected upstream and downstream. A nozzle base 110 is provided on one side of the mixing chamber 130 on the intake pipe 100, and the nozzle base 110 is used to install a urea nozzle; a mixing plate 400 is provided at the downstream end of the first outlet pipe 300, and the mixing plate 400 is provided with a first mixing hole 410 and / or a second mixing hole 420. The exhaust gas flows into the mixing device through the upstream end (i.e., the air inlet) of the intake pipe 100, and the urea aqueous solution flows into the mixing chamber 130 through the nozzle base 110. The spoiler 500 is closer to the exhaust gas flow than the nozzle base 110, so that the exhaust gas flows into the mixing chamber 130 to mix with the urea aqueous solution after contacting the spoiler 500 in the intake chamber 120. The spoiler 500 prevents the high-speed exhaust gas flow from directly sweeping the urea aqueous solution entering the mixing chamber 130 from the nozzle base 110, thereby preventing the generation of urea crystals. The mixed gas enters the mixing pipe 200 and is broken by the breaking plate 230 to improve the uniformity of ammonia mixing in the mixing device and reduce the risk of urea crystallization. The mixed gas then passes through the stretching end cover 220 to adjust the back pressure and the uniformity of ammonia mixing in the mixing device. Finally, it passes through the mixing plate 400 for final mixing and enters the SDPF from the downstream end (i.e., the exhaust port) of the first outlet pipe 330, and the mixing process of the entire urea mixing device is completed.

[0039] It should be noted that the first mixing holes 410 or the second mixing holes 420 need to be arranged in a circle and try to ensure that the exhaust gas flow is concentrated in the center of the mixing plate 400. The shape of the first mixing holes 410 or the second mixing holes 420 is set according to actual needs without special requirements.

[0040] In one embodiment, the spoiler 500 is arranged in the middle of the cross-section of the intake pipe 100, so that the channel cross-sections formed between the two side edges of the spoiler 500 and the inner surface of the intake pipe 100 are the same; the exhaust gas flow passes through the two sides of the spoiler 500, flows around the spoiler 500, and forms two obvious vortices after bypassing the spoiler 500. The airflow of the two vortices is mixed with urea, thereby improving the heat exchange between urea and the airflow, thereby accelerating the evaporation of the urea aqueous solution.

[0041] In some embodiments, the spoiler 500 is in the shape of an arc or a plate. In this embodiment, an interference flow hole 510 is further added to the spoiler 500 to adjust the flow rate of the exhaust gas flow, purge the urea aqueous solution, and prevent urea from forming urea crystals on the side of the spoiler 500 close to the nozzle base 110.

[0042] In one embodiment, as shown in the attached Figure 1As shown, the axis of the mixing plate 400 is eccentrically arranged relative to the axis of the nozzle base 110; the center of the eccentrically arranged mixing plate 400 is closer to the inlet of the SDPF, and the arrangement of an elbow can be omitted.

[0043] It is easy to understand that the problem of airflow deviation when the mixing plate 400 is eccentric can be solved by using the structure of the stretched end cap 220, as shown in the attached Figure 2 As shown, the third airflow adjustment hole 225 of the stretching end cover 220 is closer to the downstream end of the first air outlet pipe 300 (i.e., the center of the mixing plate 400), the flow at the third airflow adjustment hole 225 is large, and the flow at the first airflow adjustment hole 223 or the second airflow adjustment hole 224 is small, so that the airflow is more concentrated in the center of the mixing plate 400.

[0044] In order to make the mixing device more compatible with the inlet of the SDPF, a second outlet pipe 600 is provided at the downstream end of the first outlet pipe 300; the second outlet pipe 600 is trumpet-shaped, and its outlet cross-sectional area is larger than its inlet cross-sectional area.

[0045] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A SDPF tightly coupled urea mixing device, characterized in that: The invention comprises an air intake pipe (100), a mixing pipe (200) and a first air outlet pipe (300) which are connected in sequence, wherein the air intake pipe (100) is used to install a urea nozzle, and the mixing pipe (200) comprises: A hump pipe (210), comprising a first straight pipe section (211), a hump section (212), and a second straight pipe section (213) connected in sequence, wherein the upstream end of the first straight pipe section (211) is connected to the downstream end of the air intake pipe (100); The stretch end cover (220) comprises a first annular sheet (221) and a blocking sheet (222), wherein the upstream end of the first annular sheet (221) is sealingly connected to the inner surface of the first straight pipe section (211), and the blocking sheet (222) is arranged at the downstream end of the first annular sheet (221) to partially block the first annular sheet (221), wherein the outer surface of the first annular sheet (221) covers the groove on the inner side of the hump section (212); a crushing plate (230) arranged on the inner surface of the first straight pipe section (211) and located upstream of the stretching end cover (220); A clamp (240) and a connecting pipe (250), wherein the connecting pipe (250) is sleeved on the second straight pipe section (213), the downstream end of the connecting pipe (250) is connected to the upstream end of the first air outlet pipe (300), and the connecting pipe (250) is tightly matched with the hump section (212) through the clamp (240).

2. The SDPF tightly coupled urea mixing device according to claim 1, characterized in that: The inner diameter of the first straight pipe section (211), the inner diameter of the second straight pipe section (213) and the outer diameter of the first annular sheet (221) are the same; or, The inner diameter of the first straight pipe section (211) is greater than the inner diameter of the second straight pipe section (213); part of the outer diameter of the first annular sheet (221) shrinks toward its downstream end to form a tapered section (221a); ​​the outer surface of the tapered section (221a) is tightly matched with the inner surface of the second straight pipe section (213).

3. The SDPF tightly coupled urea mixing device according to claim 1, characterized in that: The baffle (222) partially covers the downstream end of the first annular sheet (221), so that a third airflow adjustment hole (225) is formed between the edge of the baffle (222) and the inner surface of the first annular sheet (221).

4. The SDPF tightly coupled urea mixing device according to claim 3 is characterized in that: The baffle (222) completely covers the downstream end of the first annular sheet (221); or, the baffle (222) is provided with a first airflow adjustment hole (223) and / or a second airflow adjustment hole (224) penetrating therethrough.

5. The SDPF tightly coupled urea mixing device according to any one of claims 1 to 4, characterized in that: The connecting pipe (250) comprises a third straight pipe section (251) and a flanged section (252); the third straight pipe section (251) is sleeved on the outer surface of the second straight pipe section (213); the flanged section (252) extends along the outer surface of the hump section (212); and the clamp (240) clamps the flanged section (252) and the hump section (212) together.

6. The SDPF tightly coupled urea mixing device according to claim 5, characterized in that: A sealing gasket (260) is provided between the flange section (252) and the hump section (212).

7. The SDPF tightly coupled urea mixing device according to any one of claims 1 to 4, characterized in that: The crushing plate (230) comprises a second annular plate (231) and a crushing plate (232); the second annular plate (231) is sealingly connected to the inner surface of the first straight pipe section (211); the crushing plate (232) forms a first flip blade (233) and a second flip blade (234) toward the downstream of the hump pipe (210); the first flip blade (233) and the second flip blade (234) have different flip directions.

8. The SDPF tightly coupled urea mixing device according to any one of claims 1 to 4, characterized in that: A spoiler (500) is arranged inside the intake pipe (100), the spoiler (500) dividing the intake pipe (100) into an intake chamber (120) and a mixing chamber (130) which are connected upstream and downstream, and a nozzle base (110) is arranged on one side of the mixing chamber (130) on the intake pipe (100), the nozzle base (110) being used for mounting a urea nozzle.

9. The SDPF close-coupled urea mixing device according to claim 8, characterized in that: A mixing plate (400) is provided at the downstream end of the first air outlet pipe (300), the mixing plate (400) being provided with a first mixing hole (410) and / or a second mixing hole (420), and the axis of the mixing plate (400) being arranged eccentrically relative to the axis of the nozzle base (110).

10. The SDPF close-coupled urea mixing device according to any one of claims 1 to 4, characterized in that: A second air outlet pipe (600) is provided at the downstream end of the first air outlet pipe (300).

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