Tight coupling scr mixer and dual injection aftertreatment system

Abstract

The utility model provides a kind of tight coupling SCR mixer, including mixing pipe, mixing pipe includes air inlet, gas outlet and barrel pipe body, air inlet is located at one end of barrel pipe body, air inlet is used to be connected with supercharger gas outlet end, gas outlet is located at the other end of the barrel pipe body, the pipe wall of the barrel pipe body is provided with nozzle seat installation mouth, nozzle seat installation mouth is used to install nozzle seat, the inner chamber of the barrel pipe body is provided with flow guide baffle and cyclone vane, flow guide baffle is located between the air inlet and the nozzle seat installation mouth, cyclone vane is located between the flow guide baffle and the gas outlet, so that the airflow entering from the air inlet is first adjusted airflow direction by flow guide baffle to prevent airflow from blowing injection droplet to the inner wall of the barrel pipe body, then after forming cyclone gas by the cyclone vane and mixing with injection droplet, discharge from the gas outlet.The utility model also provides corresponding double-injection aftertreatment system.

Description

Technical Field

[0001] This utility model belongs to the field of exhaust gas treatment technology, specifically relating to a tightly coupled SCR mixer and a dual-injection aftertreatment system. Background Technology

[0002] As domestic diesel vehicle emission regulations continue to be upgraded, stricter requirements are being placed on vehicle exhaust aftertreatment systems and their core component, the mixer. As a critical component of the aftertreatment system, the performance of the mixer directly affects NOx emissions. The "China VII" emission standard imposes stricter emission limits under low-temperature and low-load conditions and increases the injection volume, thus increasing the risk of crystallization in the mixer. Excessive crystal formation can clog the aftertreatment channels, leading to increased back pressure in the aftertreatment system, insufficient vehicle power, and the risk of emissions exceeding regulatory limits.

[0003] The mixer needs to ensure thorough mixing of the exhaust gas and the reducing agent (such as urea solution) 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 rapidly vaporizes and mixes thoroughly with the exhaust gas during injection, which helps improve the conversion efficiency of the SCR system and reduce urea consumption. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides a tightly coupled SCR mixer and a dual-injection aftertreatment system that shortens the exhaust path, reduces heat loss, and optimizes mixing efficiency.

[0005] To solve the above-mentioned technical problems, the first aspect of this utility model provides a tightly coupled SCR mixer, characterized in that it includes a mixing tube, which comprises an air inlet, an air outlet, and a cylindrical tube body. The air inlet is located at one end of the cylindrical tube body and is used to connect to the air outlet of a booster. The air outlet is located at the other end of the cylindrical tube body. A nozzle seat mounting port is provided on the tube wall of the cylindrical tube body for mounting a nozzle seat. A flow guide baffle and a swirl vane are provided in the inner cavity of the cylindrical tube body. The flow guide baffle is located between the air inlet and the nozzle seat mounting port, and the swirl vane is located between the flow guide baffle and the air outlet. This allows the airflow entering from the air inlet to first pass through the flow guide baffle to adjust the airflow direction to prevent the airflow from blowing the jet droplets onto the inner wall of the cylindrical tube body, and then pass through the swirl vane to form a swirling gas that mixes with the jet droplets before being discharged from the air outlet.

[0006] Preferably, the nozzle seat is installed in an angle of 20° to 120° between the injection direction and the air intake direction.

[0007] Preferably, the nozzle seat is installed in such a way that the injection direction is inclined relative to the axial direction of the cylindrical tube, and the injection direction forms an angle of 20° to 80° with the air intake direction.

[0008] Preferably, the swirl vane is fixedly connected to the inner wall of the cylindrical tube, and the gas passing through the swirl vane forms a swirling gas flow through the vane.

[0009] Preferably, the flow guide baffle forms an angle of 20° to 120° with the axial direction of the cylindrical tube.

[0010] Preferably, the installation position of the flow guide baffle corresponds to the position of the nozzle seat mounting port.

[0011] Preferably, the dimensions of the flow guide baffle correspond to the dimensions of the nozzle seat mounting port.

[0012] The second aspect of this utility model provides a dual-injection aftertreatment system, characterized in that it includes the aforementioned tightly coupled SCR mixer, wherein the air inlet of the tightly coupled SCR mixer is connected to the air outlet of the turbocharger, and the air outlet of the tightly coupled SCR mixer is sequentially connected to a connecting pipe, a pre-stage SCR or ASC, a DOC, a DPF, a mixer, and a post-stage SCR or ASC, and both the tightly coupled SCR mixer and the mixer are equipped with nozzles.

[0013] This utility model discloses a tightly coupled SCR mixer and a dual-injection aftertreatment system for vehicles, which is arranged close to the turbocharger outlet. By shortening the exhaust path, reducing heat loss, and optimizing mixing efficiency, it brings multiple technical advantages to the aftertreatment system of commercial vehicles:

[0014] It has a compact structure and short length, which can adapt to various application connection requirements and facilitates the design of subsequent connection pipelines;

[0015] Tightly coupled, compact design with low back pressure;

[0016] Less heat loss facilitates a rapid increase in the SCR inlet temperature to the catalyst reaction window temperature, effectively reducing nitrogen oxide emissions during the cycle.

[0017] Being close to the booster results in less energy loss, which is beneficial to the urea pyrolysis reaction and improves the evaporation efficiency of the urea solution.

[0018] Located near the turbocharger, it minimizes energy loss, significantly reducing the risk of urea crystallization; and under high-temperature conditions, it minimizes heat loss, effectively removing crystals and reducing crystallization failure. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the dual-injection aftertreatment system of this utility model.

[0020] Figure 2 This is a schematic diagram of the tightly coupled SCR mixer of this utility model.

[0021] Figure 3 This is a schematic diagram illustrating the working principle of the tightly coupled SCR mixer of this utility model. Detailed Implementation

[0022] To make the technical problem solved by this utility model clearer, the present utility model is further described below with reference to embodiments and accompanying drawings. The specific embodiments described herein are only for explaining the present utility model and are not intended to limit the present utility model.

[0023] like Figure 1 The diagram shows a schematic of the dual-injection aftertreatment system of this invention, used in automotive emission aftertreatment systems. This dual-injection aftertreatment system includes a tightly coupled SCR mixer 5. The inlet of the tightly coupled SCR mixer 5 is connected to the outlet 16 of the turbocharger. The outlet of the tightly coupled SCR mixer 5 is sequentially connected to a connecting pipe 7, a pre-stage SCR or ASC 8, a DOC 9, a DPF 10, a mixer 12, and a post-stage SCR or ASC 13. The tightly coupled SCR mixer 5 is equipped with a first nozzle 6, and the mixer 12 is equipped with a second nozzle 11. The reducing agent can be injected into the tightly coupled SCR mixer through the first nozzle 6 and into the mixer 12 through the second nozzle 11. Urea droplets mix with the high-temperature exhaust gas inside each mixer. The urea aqueous solution absorbs heat to generate ammonia. Under the action of the SCR catalyst, the nitrogen oxides in the exhaust gas undergo a reduction reaction with the ammonia.

[0024] Among them, DOC (Diesel Oxidation Catalyst) is a diesel engine oxidation catalyst, DPF (Diesel Particulate Filter) is a diesel particulate filter, SCR (Selective Catalytic Reduction) is a selective catalytic reduction catalyst, and ASC (Ammonia Slip Catalyst) is an ammonia oxidation catalyst. DOC, DPF, SCR, and ASC all contain catalyst supports.

[0025] like Figure 1 As shown, the tightly coupled SCR mixer 5, connecting pipe 7, pre-stage SCR or ASC 8, DOC 9, DPF 10, mixer 12, and post-stage SCR or ASC 13 form an internal chamber for the engine's high-temperature exhaust gas to pass through.

[0026] like Figures 2 to 3As shown, this is an embodiment of the tightly coupled SCR mixer 5 of the present invention. The tightly coupled SCR mixer is directly connected to the turbocharger outlet at the exhaust end of the engine, with a very short physical distance, which reduces exhaust heat loss and shortens the gas flow path, thereby improving mixing efficiency. The tightly coupled SCR mixer 5 includes a mixing tube 1, which includes an air inlet, an air outlet, and a cylindrical tube body 15. The air inlet is located at one end of the cylindrical tube body 15 and is used to connect to the air outlet 16 of the booster. The air outlet is located at the other end of the cylindrical tube body 15. A nozzle seat mounting port 14 is provided on the tube wall of the cylindrical tube body 15. The nozzle seat mounting port 14 is used to install a nozzle seat 4. A first nozzle 6 is installed in the nozzle seat 4. A flow guide baffle 3 and a swirl vane 2 are provided in the inner cavity of the cylindrical tube body 15. The flow guide baffle 3 is located between the air inlet and the nozzle seat mounting port 14. The swirl vane 2 is located between the flow guide baffle 3 and the air outlet. The swirl vane 2 is used to enhance the mixing effect, and the flow guide baffle 3 is used to regulate the internal airflow.

[0027] The airflow entering from the air inlet first passes through the guide baffle 3 to adjust the airflow direction to prevent the airflow from blowing the sprayed droplets onto the inner wall of the cylindrical tube 15. Then, it passes through the swirl vane 2 to form a swirling gas, which mixes with the sprayed droplets and is then discharged from the air outlet.

[0028] Thus, engine exhaust gas enters the intake of the tightly coupled mixer through the turbocharger outlet, where it passes through the baffle and swirl vanes to form rotating gas, which mixes with the urea droplets injected from the nozzle. The baffle effectively regulates the airflow direction, protecting the urea jet from the nozzle and ensuring good droplet distribution throughout the mixing chamber. The baffle also effectively prevents the airflow from blowing urea droplets onto the upper wall of the swirl tube, reducing the risk of crystallization. The gas passing through the swirl vanes forms a swirling gas stream, enhancing the mixing of gas and urea droplets and improving urea evaporation efficiency.

[0029] The nozzle seat 4 is installed in such a way that the spray direction forms an angle of 20° to 120° with the air intake direction, which is the axial direction of the mixing pipe. Specifically, the nozzle seat 4 is installed in such a way that the spray direction is inclined relative to the axial direction of the cylindrical tube 15, and the spray direction forms an angle of 20° to 80° with the air intake direction.

[0030] The swirl vane 2 is fixedly connected to the inner wall of the cylindrical tube 15. The vane 2 causes the gas passing through it to form a swirling flow. Swirling flow can be formed by adjusting the shape of the vane and the swirl parameters. This invention does not limit the shape of the vane or the swirl parameters; any vane capable of forming a swirling flow is acceptable. The swirl vane 2 can be fixed to the inner wall of the cylindrical tube 15 by welding or other methods. Preferably, the installation position of the swirl vane 2 corresponds to the position of the nozzle seat mounting port.

[0031] The flow guide baffle 3 forms an angle of 20° to 120° with the axial direction of the cylindrical tube 15. The installation position of the flow guide baffle 3 corresponds to the position of the mounting port 14 of the nozzle seat 4. The dimensions of the flow guide baffle 3 correspond to the dimensions of the mounting port 14 of the nozzle seat 4.

[0032] This utility model discloses a tightly coupled SCR mixer and a dual-injection aftertreatment system for vehicles, which is arranged close to the turbocharger outlet. By shortening the exhaust path, reducing heat loss, and optimizing mixing efficiency, it brings multiple technical advantages to the aftertreatment system of commercial vehicles:

[0033] It has a compact structure and short length, which can adapt to various application connection requirements and facilitates the design of subsequent connection pipelines;

[0034] Tightly coupled, compact design with low back pressure;

[0035] Less heat loss facilitates a rapid increase in the SCR inlet temperature to the catalyst reaction window temperature, effectively reducing nitrogen oxide emissions during the cycle.

[0036] Being close to the booster results in less energy loss, which is beneficial to the urea pyrolysis reaction and improves the evaporation efficiency of the urea solution.

[0037] Located near the turbocharger, it minimizes energy loss, significantly reducing the risk of urea crystallization; and under high-temperature conditions, it minimizes heat loss, effectively removing crystals and reducing crystallization failure.

[0038] The above descriptions are specific embodiments of this utility model and do not constitute a limitation on the scope of protection of this utility model. Any modifications and variations made to the technical concept of this utility model should be included within the scope of protection of this utility model.

Claims

1. A tightly coupled SCR mixer, characterized in that, The system includes a mixing tube comprising an air inlet, an air outlet, and a cylindrical tube body. The air inlet is located at one end of the cylindrical tube body and is used to connect to the air outlet of a turbocharger. The air outlet is located at the other end of the cylindrical tube body. A nozzle seat mounting port is provided on the tube wall of the cylindrical tube body for mounting a nozzle seat. A flow guide baffle and a swirl vane are provided in the inner cavity of the cylindrical tube body. The flow guide baffle is located between the air inlet and the nozzle seat mounting port, and the swirl vane is located between the flow guide baffle and the air outlet. This allows the airflow entering from the air inlet to first pass through the flow guide baffle to adjust the airflow direction and prevent the airflow from blowing the jet droplets onto the inner wall of the cylindrical tube body. Then, it passes through the swirl vane to form a swirling gas, which mixes with the jet droplets before being discharged from the air outlet.

2. The tightly coupled SCR mixer according to claim 1, characterized in that, The nozzle seat is installed in such a way that the spray direction and the air intake direction form an angle of 20° to 120°.

3. The tightly coupled SCR mixer according to claim 1, characterized in that, The nozzle seat is installed in such a way that the spray direction is inclined relative to the axial direction of the cylindrical tube, and the spray direction forms an angle of 20° to 80° with the air intake direction.

4. The tightly coupled SCR mixer according to claim 1, characterized in that, The swirl vanes are fixedly connected to the inner wall of the cylindrical tube, and the gas passing through the swirl vanes forms a swirling gas flow.

5. The tightly coupled SCR mixer according to claim 1, characterized in that, The flow guide baffle forms an angle of 20° to 120° with the axial direction of the cylindrical tube.

6. The tightly coupled SCR mixer according to claim 1, characterized in that, The installation position of the flow guide baffle corresponds to the position of the nozzle seat mounting port.

7. The tightly coupled SCR mixer according to claim 1, characterized in that, The dimensions of the flow guide baffle correspond to the dimensions of the nozzle seat mounting port.

8. A dual-injection aftertreatment system, characterized in that, The invention includes a tightly coupled SCR mixer as described in any one of claims 1 to 7, wherein the air inlet of the tightly coupled SCR mixer is connected to the air outlet of the booster, and the air outlet of the tightly coupled SCR mixer is sequentially connected to a connecting pipe, a pre-stage SCR or ASC, a DOC, a DPF, a mixer, and a post-stage SCR or ASC, and both the tightly coupled SCR mixer and the mixer are provided with nozzles.

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