End cover integrated SCR mixer and corresponding exhaust system
The design of the end cover integrated SCR mixer solves the problems of unsatisfactory mixing effect and high back pressure of the mixer under the National VII regulations, and achieves improved SCR system performance with efficient mixing and low crystallization.
Patent Information
- Application Number
- CN202423242510.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-27
- Publication Date
- 2025-10-24
- Estimated Expiration
- 2034-12-27
AI Technical Summary
Under the National VII regulations, existing mixers have problems such as unsatisfactory mixing effect, high back pressure, and easy crystallization, which leads to the decline of SCR system performance.
An end-cover integrated SCR mixer is designed, in which the mixer air inlet and nozzle are independently integrated on the side wall of the end-cover shell. The exhaust gas is mixed with the reducing agent in the mixing tube. The mixer and SCR are integrated on the end cover, and a swirl blade and arc plate structure are used to improve mixing efficiency and prevent crystallization.
A highly integrated, low-back-pressure mixer structure is achieved, which improves the mixing effect and reduces the risk of urea crystallization, thereby enhancing the conversion efficiency and fuel economy of the SCR system.
Smart Images
Figure CN223469319U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to tail gas treatment technical field, especially a kind of end cap integrated SCR mixer and corresponding exhaust system. BACKGROUND
[0002] With the continuous upgrading of domestic diesel vehicle emission regulations, more stringent requirements are put forward for automobile exhaust aftertreatment system and its core component mixer. As a key component in the aftertreatment system, the performance of the mixer directly affects the emission of NOx.
[0003] The mixer needs to ensure that the exhaust gas and the reducing agent (such as urea solution) are fully mixed to improve the conversion efficiency of the SCR system. The mixer also needs to have good heat exchange performance to ensure that the urea solution is rapidly vaporized and fully mixed with the exhaust gas during the injection process, which helps to improve the conversion efficiency of the SCR system and reduce urea consumption. Due to the more stringent emission limits of "China VI" standard under low temperature and low load conditions, and the increase of injection amount, the risk of crystallization of the mixer increases. The generation of a large amount of crystallization will block the aftertreatment channel, causing the back pressure of the aftertreatment system to rise, the vehicle power to be insufficient, and the risk of emission exceeding the regulatory limits.
[0004] With the upgrading of diesel engine national seven regulations, urea double injection system is one of the important solutions. Compared with the national six exhaust aftertreatment system, urea injection needs to be added at the inlet of the aftertreatment system, and a front mixer and SCR catalyst need to be added, which poses a great challenge to the boundary of the aftertreatment system. The general technical solution adopts a simple mixer in the front exhaust pipe, which has many shortcomings: the mixing effect is not ideal, the back pressure is high, and urea crystallization is easy, etc.
[0005] In general, with the upgrading of regulations, there are still problems: the space arrangement of the front mixer and the aftertreatment system is challenging under national seven; the back pressure of the mixer and the aftertreatment system is high, which leads to poor engine fuel economy; the urea crystallization in the mixer and the low mixing efficiency of urea and exhaust gas result in low De-NOx conversion efficiency, etc. SUMMARY
[0006] In view of the deficiencies of the existing technology, the utility model provides an end cap integrated SCR mixer and a corresponding exhaust system.
[0007] To achieve the above object, the utility model discloses a first aspect provides an end cover integrated formula SCR mixer has the following technical scheme: the end cover integrated formula mixer includes end cover shell, the end cover shell has the open end, the closed end opposite with the open end and the lateral wall between the open end and the closed end, the open end is used to connect SCR, first aperture and second aperture are independently arranged on the lateral wall of the end cover shell respectively, the first aperture is used to install the nozzle, the second aperture is the air inlet of the mixer, the inner chamber of the end cover shell sets up the mixing pipe and the baffle, the mixing pipe passes through the baffle and is arranged in the inner chamber of the end cover shell, the inner chamber of the end cover shell is divided into first cavity and second cavity by the baffle, the mixing pipe has the inlet for air and the outlet for air, the inlet of the mixing pipe is located in the first cavity, the outlet of the mixing pipe is located in the second cavity, the part of the open end of the end cover shell corresponding the first cavity is closed, the part of the open end of the end cover shell corresponding the second cavity is the air outlet of the mixer, so that the tail gas enters the first cavity through the air inlet of the mixer, enters the mixing pipe through the inlet of the mixing pipe, mixes with the reducing agent in the mixing pipe, and is discharged through the air outlet of the mixer and enters the SCR.
[0008] Preferably, the nozzle is installed in the first aperture through a nozzle mounting seat.
[0009] Preferably, the longitudinal axis of the mixing pipe and the longitudinal axis of the end cover shell form a preset angle, and the preset angle is 60°-120°.
[0010] Preferably, the central axes of the first aperture and the second aperture are both perpendicular to the longitudinal axis of the end cover shell.
[0011] Preferably, the part of the open end corresponding to the first cavity is closed by the baffle.
[0012] Preferably, the baffle has a plate body, the plate body is provided with a mounting hole for the mixing pipe to pass through, and the baffle has an extension part extending from the plate body towards the first cavity, and the part of the open end corresponding to the first cavity is closed by the extension part.
[0013] Preferably, an arc plate is arranged below the outlet of the mixing pipe, at least one side of the arc plate has a concave channel, so that the mixed gas flowing out of the outlet of the mixing pipe is discharged through the concave channel and the air outlet.
[0014] Preferably, the arc plate is provided with a plurality of third openings.
[0015] Preferably, the mixing tube includes a swirl tube with swirl blades inside, and several blade windows are set on the upper part of the swirl tube. The several blade windows form the inlet of the mixing tube. When the gas enters the mixing tube through the blade windows, it forms a rotating form. The bottom end opening of the swirl tube is the outlet of the mixing tube.
[0016] A second aspect of the present invention provides an exhaust system, characterized in that it comprises an SCR and the mixer, wherein the mixer is installed on the SCR as an end cover.
[0017] The end cover integrated SCR mixer and the corresponding exhaust system of the utility model utilize the end cone at the inlet of the existing after-treatment system to integrate the mixer design, which has high integration, compact space, low back pressure, good mixing effect and excellent anti-crystallization performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments.
[0019] Figure 1 This is a simplified diagram of the exhaust system of the present invention.
[0020] Figure 2 This is an exploded diagram of the end cover integrated SCR mixer of the present invention.
[0021] Figure 3 This is a schematic diagram illustrating the working principle of the end cover integrated SCR mixer of the present utility model.
[0022] Figure 4 This is a partial structural diagram of the end cover integrated SCR mixer of the present utility model.
[0023] Reference numerals
[0024] 1 partition; 101 first cavity; 102 second cavity; 2 mixing tube; 3 swirl blade; 4 arc plate; 5 end cover shell; 6 sealing plate; 7 nozzle seat; 8 end cover integrated SCR mixer; 9 SCR; 10 first opening; 11 second opening; 12 open end. DETAILED DESCRIPTION
[0025] In order to more clearly describe the technical content of the present invention, it is further described below in conjunction with specific embodiments.
[0026] like Figure 1As shown in the figure, it is a principle schematic view of the exhaust system of the utility model. Among them the exhaust system includes SCR 9 and end cap integrated SCR mixer 8, end cap integrated SCR mixer 8 is installed and connected as end cap on SCR 9. Exhaust gas enters through end cap integrated SCR mixer 8, and mixes with reducing agent sprayed by nozzle and exchanges heat, and then mixed gas enters SCR (Selective Catalytic Reduction, selective catalytic reduction) through end cap integrated SCR mixer 8, and reduction reaction occurs.
[0027] As Figures 2 to 4 As shown in the figure, it is a specific embodiment of the end cap integrated SCR mixer 8 of the utility model. The end cap integrated mixer 8 includes end cap shell 5, the end cap shell 5 has open end 12, the closed end opposite to the open end and the side wall between the open end and the closed end, the open end 12 is used to connect SCR 9, first opening 10 and second opening 11 are independently arranged on the side wall of the end cap shell 5 respectively, the first opening 10 is used to install nozzle, the second opening 11 is the gas inlet of the mixer, engine exhaust gas enters the mixer through the gas inlet to mix with reducing agent, the inner cavity of the end cap shell 5 is provided with mixing pipe 2 and partition plate 1, the mixing pipe 2 is arranged in the inner cavity of the end cap shell 5 through the partition plate 1, as Figure 3 As shown in the figure, the inner cavity of the end cap shell 5 is divided into first cavity 101 and second cavity 102 by the partition plate 1, the mixing pipe 2 has inlet for gas and outlet for gas, the inlet of the mixing pipe 2 is located in the first cavity 101, the outlet of the mixing pipe 2 is located in the second cavity 102, the part of the open end 12 of the end cap shell 5 corresponding to the first cavity 101 is closed, the part of the open end 12 of the end cap shell 5 corresponding to the second cavity 102 is the gas outlet of the mixer, mixed gas is discharged from the gas outlet, so that exhaust gas enters the first cavity 101 through the gas inlet of the mixer, enters the mixing pipe 2 through the inlet of the mixing pipe 2, mixes with reducing agent in the mixing pipe 2, and is discharged through the outlet of the mixing pipe 2 and enters SCR through the gas outlet of the mixer.
[0028] The end cap integrated SCR mixer provided by the utility model integrates the end cap of encapsulated aftertreatment and mixer parts, creatively integrates the gas inlet of the mixer and the nozzle on the side wall of the end cap shell, exhaust gas mixes with reducing agent in the mixing pipe after entering the inner cavity, and the open end of the end cap shell can be directly connected with SCR, the utility model creates the mixer structure with high integration degree and compact space, and has low back pressure and good mixing effect.
[0029] The nozzle is installed in the first opening 10 through the nozzle mounting seat 7. The first opening 10 is provided with a sealing plate 6 for mounting the nozzle mounting seat 7, and the mixing pipe 2 passes through the opening of the sealing plate 6 to enable the nozzle to spray the reducing agent into the mixing pipe 2.
[0030] As shown in Figures 2 to 3 , the end cover shell 5 has a longitudinal axis, the longitudinal axis of the end cover shell 5 passes through the open end 12 and the closed end, and the longitudinal axis of the mixing pipe 2 is perpendicular to the longitudinal axis of the end cover shell 5. The central axes of the first opening 10 and the second opening 11 are both perpendicular to the longitudinal axis of the end cover shell 5, and the first opening 10 and the second opening 11 are both arranged on the side wall of the end cover shell 5. The mixing pipe 2 can also be arranged in a non-perpendicular state in the inner cavity of the end cover shell, for example, inclined at an angle of 60°-120°.
[0031] As shown in Figure 3 and Figure 4 , the portion of the open end 12 corresponding to the first cavity 101 is closed by the partition plate 1.
[0032] Specifically, the partition plate 1 has a plate body provided with a mounting hole for the mixing pipe 2 to pass through, and has an extension part extending from the plate body towards the first cavity 101, which closes the portion of the open end 12 corresponding to the first cavity 101.
[0033] As shown in Figures 2 to 4 , an arc plate 4 is arranged below the outlet of the mixing pipe 2, and both sides of the arc plate 4 have concave channels, so that the mixed gas flowing out of the outlet of the mixing pipe 2 is discharged through the concave channels and the gas outlet. The arc plate 4 used in this embodiment is in the shape of a bowl as a whole.
[0034] In this embodiment, the arc plate 4 is provided with a plurality of third openings. High-temperature gas can enter the bottom of the arc plate through the third openings to remove the urea liquid film and urea crystals that may accumulate in the space between the arc plate bottom and the arc wall of the end cover shell 5, effectively improving the crystallization performance, and at the same time, facilitating the evaporation of urea and the improvement of ammonia mixing efficiency.
[0035] As shown in Figures 2 to 4As shown, the mixing pipe 2 comprises a cyclone pipe with cyclone vanes 3, the upper part of the cyclone pipe 2 is provided with a plurality of vane windows, the plurality of vane windows form the inlet of the mixing pipe 2, and when gas enters the mixing pipe 2 through the vane windows, the gas forms a rotating shape, and the bottom opening of the cyclone pipe 2 is the outlet of the mixing pipe 2. Based on the vane windows and the cyclone vanes of the cyclone pipe, the end cover integrated SCR mixer of the utility model forms high-efficiency cyclone inside, and the performance is excellent. The side wall of the cyclone pipe can be perforated, and the vanes in the vane windows can be inward or outward.
[0036] The end cover integrated SCR mixer and the corresponding exhaust system of the utility model utilize the end cone at the inlet of the existing aftertreatment system, integrate the design of the mixer, have high integration degree, compact space, low back pressure, good mixing effect and excellent anti-crystallization performance.
[0037] In this specification, the utility model has been described with reference to its specific embodiments. However, it is obvious that various modifications and changes can be made without departing from the spirit and scope of the utility model. Therefore, the specification and drawings should be considered as illustrative rather than restrictive.
Claims
1. An end cap integrated SCR mixer characterized by, The end cover shell has an open end, a closed end opposite to the open end, and a side wall between the open end and the closed end, the open end is used to connect the SCR, the first opening and the second opening are independently arranged on the side wall of the end cover shell, the first opening is used to install the nozzle, and the second opening is an air inlet of the mixer, an inner cavity of the end cover shell is provided with a mixing pipe and a partition plate, the mixing pipe is arranged in the inner cavity of the end cover shell and passes through the partition plate, the inner cavity of the end cover shell is divided into a first cavity and a second cavity by the partition plate, the mixing pipe has an inlet for air and an outlet for air, the inlet of the mixing pipe is located in the first cavity, the outlet of the mixing pipe is located in the second cavity, a part of the open end of the end cover shell corresponding to the first cavity is closed, and a part of the open end of the end cover shell corresponding to the second cavity is an air outlet of the mixer, so that the exhaust gas enters the first cavity through the air inlet of the mixer, enters the mixing pipe through the inlet of the mixing pipe, is mixed with the reducing agent in the mixing pipe, is discharged through the outlet of the mixing pipe, and enters the SCR through the air outlet of the mixer.
2. The end cap integrated SCR mixer of claim 1, wherein, The nozzle is installed in the first opening through the nozzle mounting seat.
3. The end cap integrated SCR mixer of claim 1, wherein, A longitudinal axis of the mixing pipe and a longitudinal axis of the end cover shell form a preset angle, and the preset angle is 60°-120°.
4. The end cap integrated SCR mixer of claim 3, wherein, Center axes of the first opening and the second opening are perpendicular to the longitudinal axis of the end cover shell.
5. The end cap integrated SCR mixer of any one of claims 1-4, wherein, The part of the open end corresponding to the first cavity is closed by the partition plate.
6. The end cap integrated SCR mixer of claim 5, wherein, The partition plate has a plate body, the plate body is provided with a mounting hole for the mixing pipe to pass through, and the partition plate has an extension part extending from the plate body towards the first cavity, and the part of the open end corresponding to the first cavity is closed through the extension part.
7. The end cap integrated SCR mixer of claim 1, wherein, An arc plate is arranged below the outlet of the mixing pipe, at least one side of the arc plate has a concave channel, so that the mixed gas flowing out of the outlet of the mixing pipe is discharged through the air outlet through the concave channel.
8. The end cap integrated SCR mixer of claim 7, wherein, The arc plate is provided with a plurality of third openings.
9. The end cap integrated SCR mixer of claim 1, wherein, The mixing pipe comprises a cyclone pipe internally provided with a cyclone vane, an upper portion of the cyclone pipe is provided with a plurality of vane windows, the plurality of vane windows form the inlet of the mixing pipe, and gas entering the mixing pipe through the vane windows forms a rotating mode, and an open bottom end of the cyclone pipe is the outlet of the mixing pipe.
10. An exhaust system characterized by, The mixer of any one of claims 1-9 is installed on the SCR as an end cover.