Selective catalytic reduction catalysts, exhaust systems and vehicles
By incorporating high-temperature and low-temperature treatment components in the selective catalytic reduction catalyst to handle high-temperature and low-temperature gas flows respectively, and combining them with swirl plates and flow dividers, the problem of insufficient catalyst activity under low-temperature and high-temperature conditions is solved, achieving higher NOx conversion rates and stability of exhaust emission standards.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GREAT WALL MOTOR CO LTD
- Filing Date
- 2025-08-04
- Publication Date
- 2026-07-31
AI Technical Summary
Existing selective catalytic reduction catalysts have insufficient catalyst activity under low and high temperature conditions, resulting in low NOx conversion rates and difficulty in meeting exhaust emission standards. In particular, the catalyst is easily damaged during cold starts and high-load operation of diesel vehicles.
The design includes high-temperature and low-temperature treatment components, each equipped with catalysts suitable for high and low temperatures. A switching module selectively opens or closes the corresponding channels based on the gas flow temperature for purification. Swirl plates and flow dividers are installed in each component to improve gas flow mixing uniformity and catalyst efficiency.
The reduction efficiency, stability, and adaptability of nitrogen oxides are improved over a wider temperature range, while the energy consumption of the temperature control device is reduced, thus meeting exhaust emission standards.
Smart Images
Figure CN224579382U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of exhaust gas catalytic treatment technology, and in particular to a selective catalytic reduction catalyst, an exhaust assembly, and a vehicle. Background Technology
[0002] As people's living standards improve, automobiles, as a basic means of transportation, are used more and more frequently in daily life. This has led to a rapid increase in vehicle exhaust emissions, significantly impacting air pollution. Consequently, countries worldwide are raising their standards for exhaust emission treatment. In existing technologies, SCR (Selective Catalytic Reduction) technology utilizes a catalyst to promote the reduction reaction of nitrogen oxides (NOx) with a reducing agent (such as NH3) within a specific temperature window, producing harmless N2 and H2O. However, the catalyst's activity is strongly temperature-dependent. At low and high temperatures, the binding force between the catalyst's surface active sites and the reactants is insufficient, resulting in a low NOx conversion rate and ineffective NOx reduction. This leads to unstable exhaust emission standards and difficulty in meeting international requirements.
[0003] Currently, traditional selective catalytic reduction catalysts typically have only one catalytic reaction zone, where low-temperature gas flow, high-temperature gas flow, and normal exhaust gas flow all undergo reduction reactions with the catalyst. Because there is only one catalytic reaction zone, the catalyst needs to convert NOx over a wide temperature range.
[0004] However, in the above-mentioned existing technologies, taking diesel vehicles as an example in practical applications, when diesel vehicles are cold-started or frequently start-stop, the catalyst may not be able to reach the ignition temperature. Furthermore, the engine may run under high load for a long time, resulting in excessively high exhaust temperature and permanent damage to the catalyst. All of these factors restrict the conversion efficiency of the SCR system. Utility Model Content
[0005] This application addresses, to at least some extent, one of the technical problems in the related art.
[0006] Therefore, this application aims to provide a selective catalytic reduction catalyst, an exhaust assembly, and a vehicle, which is intended to purify high-temperature airflow and low-temperature airflow respectively by setting high-temperature treatment components and low-temperature treatment components. By setting catalysts suitable for high-temperature environments and catalysts suitable for low-temperature environments, the limitations of traditional single catalysts on temperature boundaries are broken, thereby improving the temperature treatment range of the selective catalytic reduction catalyst of this application, and thus improving the reduction efficiency of nitrogen oxides in exhaust gas.
[0007] To achieve the above objectives, in a first aspect, this application provides a selective catalytic reduction catalyst, comprising: High-temperature processing components, including: High-temperature channel, which is used for the passage of high-temperature airflow; A first processing device is used to purify the high-temperature airflow, and the first processing device is located inside the high-temperature channel; A cryogenic treatment assembly, comprising; A low-temperature channel is used for the passage of low-temperature gas, one end of which passes through the side wall of the high-temperature channel and is embedded in the high-temperature channel; The second processing device is used to purify the low-temperature gas and is located inside the low-temperature channel.
[0008] In the technical solution, by setting up high-temperature treatment components and low-temperature treatment components, high-temperature airflow and low-temperature airflow can enter the high-temperature channel and low-temperature channel respectively. Catalysts that meet the corresponding catalytic temperature range are set in the first treatment device and the second treatment device to effectively improve the decomposition and reduction rate of nitrogen oxides, so that the vehicle exhaust emissions meet the standards.
[0009] In some embodiments of this application, the selective catalytic reduction catalyst includes: The outer tube, one end of which is the first input terminal; An inner tube is disposed inside the outer tube, and one end of the inner tube is a second input end, which is connected to the inner wall of the first input end; A bypass tube that connects the first input terminal and the second input terminal; The high-temperature channel is formed between the inner tube and the outer tube; The interior of the inner tube is the low-temperature channel; A switching module is used to turn the high-temperature channel and the low-temperature channel on or off.
[0010] In the technical solution, a switching module determines the temperature of the airflow entering the first input terminal and opens or closes the high-temperature channel and the low-temperature channel based on the temperature, allowing the airflow to enter the high-temperature channel or the low-temperature channel for purification. Taking high-temperature airflow as an example, the switching module controls the high-temperature channel to open and the low-temperature channel to close. The high-temperature airflow enters the high-temperature channel through the outer pipe, undergoes purification through the first spray nozzle and the first processing device, and is finally discharged through the outlet pipe.
[0011] In some embodiments of this application, the high-temperature processing component includes: A first spray nozzle is connected to the side wall of the high-temperature channel, and the first spray nozzle is used to spray a reducing solvent into the high-temperature channel; A swirl plate is located between the first spray nozzle and the first processing device, and the swirl plate is used to induce the high-temperature airflow to form a swirl.
[0012] In the technical solution, a swirl plate is set up to refine and uniformly disperse the urea aqueous solution into the high-temperature gas flow under the action of centrifugal force, which facilitates the improvement of the subsequent catalytic reduction rate.
[0013] In some embodiments of this application, the swirl plate includes: A fixing ring is located between the inner tube and the outer tube, and the fixing ring has a communication port; A flow deflector is located on the side of the communication port near the first processing device, and the flow deflector is used to change the movement pattern of the high-temperature airflow.
[0014] In the technical solution, by setting the guide plate to rotate clockwise or counterclockwise, the mixed airflow passing through the connection port rotates along the rotation direction of the guide plate and spirals forward along the axis of the outer pipe, thereby making the mixing of urea aqueous solution and high-temperature airflow more uniform; at the same time, the swirling flow improves gas-liquid heat transfer, thereby increasing the hydrolysis reaction rate of urea aqueous solution.
[0015] In some embodiments of this application, the high-temperature treatment assembly further includes a flow equalization plate located on the side of the swirling plate away from the first spray nozzle. The flow equalization plate is located between the inner tube and the outer tube, and the flow equalization plate has a plurality of connecting holes for dispersing and mixing the high-temperature airflow.
[0016] In the technical solution, when the mixed gas flow passes through the flow equalization plate, part of the mixed gas flow impacts the flow equalization plate. This part of the mixed gas flow suddenly changes its flow direction and mixes into the gas flow that newly arrives at the outer wall of the flow equalization plate, thereby making the urea aqueous solution more evenly distributed in the high-temperature gas flow, and thus improving the catalytic reaction efficiency of the high-temperature gas.
[0017] In some embodiments of this application, the cryogenic processing component includes: The second spray nozzle penetrates the side wall of the high-temperature channel and communicates with the low-temperature channel; A flow divider is disposed in the inner tube between the second spray nozzle and the second processing device, and the flow divider is used to divide the cryogenic gas.
[0018] In the technical solution, when the low-temperature mixed gas flow passes through the splitter, the droplets of urea solution are repeatedly cut, which effectively reduces the droplet size of the urea solution and makes the mixing in the low-temperature mixed gas flow more uniform, thereby improving the efficiency of the subsequent reduction reaction. At the same time, the structural design of the splitter causes the droplets to gather towards the axis of the inner tube, thereby reducing the amount of deposition on the inner circumferential wall of the inner tube and improving the reduction reaction efficiency of the low-temperature gas flow.
[0019] In some embodiments of this application, the first processing device includes: The first purification unit is used to hold the high-temperature catalyst. The first heat insulation element is used to block the heat transfer generated by the reaction of the high-temperature airflow.
[0020] In the technical solution, by setting a first purification unit and a first heat insulation component, the high-temperature airflow after mixing is reduced. The first heat insulation component is used to block the heat transfer generated by the high-temperature airflow reaction. At the same time, the first heat insulation component is used to block the heat transfer to the inner tube, thereby protecting the second processing device and reducing the impact of the high temperature in the first purification unit on the low-temperature airflow in the second processing device.
[0021] In some embodiments of this application, the second processing device includes: The second purification unit is used to support the low-temperature catalyst. The second heat insulation component is used to block the low-temperature airflow from reacting with the heat generated by the second purification unit.
[0022] In the technical solution, by setting a second purification unit and a second heat insulation component, the mixed low-temperature gas flow is reduced. The second heat insulation component is used to protect the second purification unit, thereby further reducing the impact of the first purification unit on the catalyst in the second purification unit.
[0023] In a second aspect, this application provides an exhaust assembly including a selective catalytic reduction catalyst as described above, the exhaust assembly including an exhaust pipe, the selective catalytic reduction catalyst being connected to the exhaust pipe for purifying treated gases.
[0024] In the technical solution, the selective catalytic reduction catalyst is connected to the exhaust pipe so that the exhaust gas discharged from the exhaust pipe can be purified by the selective catalytic reduction catalyst, and the reduced gas is then discharged into the outside atmosphere through the exhaust pipe.
[0025] Thirdly, this application provides a vehicle including a chassis, on which an exhaust assembly as described in claim 1 is disposed, and the chassis is further provided with a lifting structure for mounting the selective catalytic reduction catalyst.
[0026] In the technical solution, the selective catalytic reduction catalyst is installed in the middle of the exhaust pipe by setting up a hoisting structure, so that the selective catalytic reduction catalyst can be in a relatively stable temperature range, and this temperature range is within the temperature range of the low temperature treatment component and the high temperature treatment component.
[0027] As can be seen from the above technical solutions, additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description
[0028] Figure 1 This is a schematic diagram of the overall structure according to the embodiments of this application; Figure 2 This is a schematic diagram of the structure of the hidden portion of the outer tube according to an embodiment of this application; Figure 3 This is a schematic cross-sectional view of the embodiment according to this application; Figure 4 This is a partial cross-sectional structural schematic diagram according to an embodiment of this application; Figure 5 This is a schematic diagram of a swirl plate structure according to an embodiment of this application.
[0029] In the above figures: 100, High-temperature treatment component; 110, High-temperature channel; 120, First spray nozzle; 130, First treatment device; 131, First purification unit; 132, First gasket; 133, Second gasket; 140, Swirl plate; 141, Fixing ring; 142, Guide plate; 143, Connecting port; 150, Flow equalization plate; 160, Connecting hole; 200, Low-temperature treatment component; 210, Low-temperature channel; 220. 230. Second spray nozzle; 231. Second processing device; 232. Second purification unit; 233. Third gasket; 240. Diverter; 300. Outer pipe; 301. First input end; 302. Inlet flange; 400. Inner pipe; 401. Second input end; 500. Bypass pipe; 600. Outlet pipe; 601. Outlet flange; 700. Switching module; 701. First electromagnetic control valve; 702. Second electromagnetic control valve. Detailed Implementation
[0030] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature. In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0031] The present application will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments. It should be noted that in the automotive industry, as people pay more attention to environmental issues such as global warming, global standards for exhaust emission treatment are becoming increasingly stringent, and users' requirements for the environmental performance of automobiles are also gradually increasing.
[0032] In existing technologies, exhaust gas treatment is typically achieved using SCR technology, which stands for Selective Catalytic Reduction. The basic principle of SCR is to utilize a catalyst (primarily vanadium-based or iron-based) to promote the reaction of harmful nitrogen oxides (NOx) with a reducing agent (such as NH3) at a specific temperature, producing harmless nitrogen (N2) and water (H2O). However, the catalytic activity of this catalyst is highly temperature-dependent. When the exhaust temperature is low (below 200°C), the binding force between the active sites on the catalyst surface and the reactants is insufficient, making effective catalytic reaction difficult. This leads to a sharp drop in NOx conversion and the generation of byproducts such as ammonium sulfate, which clog the catalyst. When the exhaust temperature is high (above 450°C), the high temperature causes catalyst sintering and deactivation (catalyst particles fuse and grow, significantly reducing the specific surface area, resulting in a reduction or loss of active sites). Metal components undergo phase transformation or volatilization, causing irreversible structural damage and permanently deactivating the catalyst.
[0033] In actual operating conditions, taking diesel vehicles as an example, when a diesel vehicle is cold-started (cold start refers to the transition process from the first ignition and operation of the engine at room temperature until it reaches the normal operating temperature), the catalyst may not be able to reach the ignition temperature (ignition temperature is usually 200℃), meaning that the exhaust gas is in a low-temperature state and the catalyst activity is low. On the other hand, prolonged high-load operation of the engine may trigger high-temperature degradation, meaning that the exhaust gas is in a high-temperature state and the catalyst may become permanently deactivated. Both of these factors restrict the overall denitrification efficiency of the SCR system (the actual conversion rate fluctuates between 60% and 95%) and force manufacturers to install complex temperature control devices to improve applicability.
[0034] Based on this, this application proposes a selective catalytic reduction catalyst, an exhaust assembly, and a vehicle. This application separates high-temperature and low-temperature treatment components. High-temperature gas enters a high-temperature channel, where a first treatment device purifies the gas. Low-temperature gas enters a low-temperature channel, where a second treatment device purifies the gas. This separate treatment of the high-temperature and low-temperature gas allows the selective catalytic reduction (SCR) catalyst structure to operate over a wider temperature range. The coupling of these two components overcomes the temperature limitations of a single catalyst, improving the stability of the system's NOx reduction efficiency, reducing the energy consumption of the downstream temperature control device, and expanding the operational adaptability of SCR technology.
[0035] In the following, embodiments of this application will be described in detail with reference to the accompanying drawings.
[0036] As attached Figures 1 to 3As shown in an illustrative embodiment of the selective catalytic reduction catalyst and exhaust assembly of this application, the selective catalytic reduction catalyst includes a high-temperature treatment component 100, which is used to treat and purify high-temperature gas.
[0037] In some embodiments, the high-temperature processing component 100 includes a high-temperature channel 110 for high-temperature airflow to pass through. By providing a dedicated channel for the high-temperature airflow, it is convenient to subsequently install a corresponding high-temperature airflow processing device within the high-temperature channel 110.
[0038] In some embodiments, the high-temperature treatment assembly 100 includes a first nozzle 120, which communicates with the sidewall of the high-temperature channel 110. The first nozzle 120 is used to spray a reducing agent into the high-temperature channel 110. In the SCR catalytic reaction, urea aqueous solution is commonly used as a precursor for the reducing agent because its liquid form is easier to store and transport and has higher safety compared to gaseous reducing agents such as ammonia. The ammonia generated during decomposition reacts with nitrogen oxides in the exhaust gas through a catalytic reduction reaction, thereby converting nitrogen oxides and reducing pollutant emissions in the exhaust gas.
[0039] In some embodiments, the high-temperature component includes a first processing device 130, which is disposed inside the high-temperature channel 110. After the high-temperature airflow enters the high-temperature channel 110, it mixes with the urea aqueous solution sprayed by the first spray nozzle 120. The urea aqueous solution decomposes under high temperature to produce water and ammonia. After the mixed airflow passes through the first processing device 130, it is purified and nitrogen and water are discharged.
[0040] In some embodiments, the selective catalytic reduction catalyst includes a cryogenic treatment component 200, which is used to treat and purify cryogenic gases. When the vehicle frequently starts and stops, the temperature of the exhaust gas may be lower than 200°C, which is below the ignition temperature of the catalyst. At this time, the exhaust gas enters the cryogenic treatment component 200 to facilitate the catalytic reaction and achieve purification of the cryogenic gas exhaust.
[0041] In some embodiments, refer to Figure 3 and Figure 4 The cryogenic treatment component 200 includes a cryogenic channel 210 for the passage of cryogenic gas flow. One end of the cryogenic channel 210 passes through the side wall of the high-temperature channel 110 and is embedded within the high-temperature channel 110. By providing a dedicated channel for the cryogenic gas flow, it is convenient to subsequently install a corresponding cryogenic gas flow treatment device within the cryogenic channel 210. By embedding the cryogenic channel 210 within the high-temperature channel 110, the structure of the selective catalytic reduction catalyst is optimized to facilitate its production and assembly.
[0042] In some embodiments, the cryogenic treatment assembly 200 includes a second nozzle 220 that penetrates the sidewall of the high-temperature channel 110 and communicates with the low-temperature channel 210. The second nozzle 220 is used to spray a reducing solvent into the low-temperature channel 210, wherein the reducing solvent is an aqueous urea solution.
[0043] In some embodiments, the cryogenic treatment component 200 includes a second treatment device 230 for purifying the cryogenic gas flow. After entering the cryogenic channel 210, the cryogenic gas flow mixes with the urea aqueous solution sprayed from the second nozzle 220. At this point, the temperature of the cryogenic gas flow is "low" relative to the temperature of the high-temperature gas flow, but still higher than the pyrolysis temperature of the urea aqueous solution. The urea aqueous solution decomposes to produce water and ammonia. The mixed cryogenic gas flow is purified after passing through the second treatment device 230, and nitrogen and water are discharged.
[0044] In the above technical solution, by setting up a high-temperature treatment component 100 and a low-temperature treatment component 200, the high-temperature airflow and the low-temperature airflow can enter the high-temperature channel 110 and the low-temperature channel 210 respectively, and catalysts that meet the corresponding catalytic temperature ranges are set in the first treatment device 130 and the second treatment device 230, so as to effectively improve the decomposition and reduction rate of nitrogen oxides and make the vehicle exhaust emissions meet the standards.
[0045] In some embodiments, refer to Figure 1 The selective catalytic reduction catalyst includes an outer tube 300, one end of which is a first input end 301. Gas flow enters the outer tube 300 from the first input end 301 to achieve subsequent purification treatment.
[0046] In some embodiments, refer to Figure 2 and Figure 3 The selective catalytic reduction catalyst includes an inner tube 400, which is disposed inside the outer tube 300. One end of the inner tube 400 is a second input end 401, which is connected to the inner wall of the first input end 301.
[0047] In some embodiments, refer to Figure 1 and Figure 2 The selective catalytic reduction catalyst includes a bypass pipe 500. One end of the bypass pipe 500 is connected to the second input end 401, and the other end is connected to the outer pipe 300 near the side wall of the first input end 301, so as to connect the first input end 301 and the second input end 401. At this time, the inner pipe 400 is connected to the first input end 301 through the bypass pipe 500, so that the airflow entering from the first input end 301 can enter the outer pipe 300 or enter the inner pipe 400 through the bypass pipe 500.
[0048] In some embodiments, a high-temperature channel 110 is formed between the inner tube 400 and the outer tube 300, and a low-temperature channel 210 is formed inside the inner tube 400. That is, a first spray nozzle 120 is disposed on the side wall of the outer tube 300 near the first input end 301, and the first spray nozzle 120 communicates with the outer tube 300 to spray a reducing solvent onto the high-temperature gas flow; a first processing device 130 is located inside the high-temperature channel 110, i.e., between the outer tube 300 and the inner tube 400; a second spray nozzle 220 is disposed on the side wall of the outer tube 300 and passes through the outer tube 300 to communicate with the inner tube 400, so as to spray a reducing solvent onto the low-temperature gas flow located in the inner tube 400; a second processing device 230 is located inside the low-temperature channel 210, i.e., inside the inner tube 400.
[0049] In some embodiments, refer to Figure 3 and Figure 4 The first processing device 130 surrounds the second processing device 230, that is, the reduction reaction zones of the high-temperature gas flow and the low-temperature gas flow are located at the same position of the selective catalytic reduction catalyst, so as to simplify the structure of the selective catalytic reduction catalyst.
[0050] In some embodiments, the selective catalytic reduction catalyst includes an outlet pipe 600, which is located on the side of the outer pipe 300 away from the first input end 301, and is used to discharge purified gas.
[0051] In some embodiments, the first input terminal 301 is provided with an intake flange 302, and the end of the exhaust pipe 600 away from the first input terminal 301 is provided with an exhaust flange 601, so as to facilitate the selective catalytic reduction catalyst to be installed and connected to the vehicle structure.
[0052] In some embodiments, refer to Figure 1 and Figure 2 The selective catalytic reduction catalyst also includes a switching module 700, which is used to open or close the high-temperature channel 110 and the low-temperature channel 210. According to the positional connection relationship of the outer tube 300, the inner tube 400 and the bypass tube 500, the outer tube 300 and the inner tube 400 are arranged in parallel to form an independent flow channel.
[0053] In the above technical solution, the switching module 700 determines the temperature of the airflow entering the first input terminal 301 and opens or closes the high-temperature channel 110 and the low-temperature channel 210 according to the temperature, so that the airflow enters the high-temperature channel 110 or the low-temperature channel 210 for purification. Taking high-temperature airflow as an example, the switching module 700 controls the high-temperature channel 110 to open and the low-temperature channel 210 to close. The high-temperature airflow enters the high-temperature channel 110 through the outer pipe 300, is purified by the first spray nozzle 120 and the first processing device 130, and is finally discharged through the exhaust pipe 600.
[0054] In some embodiments, the switching module 700 includes a temperature sensor disposed at the first input port 301. The temperature sensor is used to detect the temperature of the airflow entering the first input port 301 so that the subsequent switching module 700 controls the high-temperature channel 110 or the low-temperature channel 210 to open or close, so that the airflow enters the high-temperature channel 110 or the low-temperature channel 210 for purification.
[0055] In some embodiments, the switching module 700 includes a first electromagnetic control valve 701 disposed in the outer tube 300. The first electromagnetic control valve 701 is located on the side of the outer tube 300 near the first input end 301. The first electromagnetic control valve 701 is used to control the connection between the high temperature channel 110 and the first input end 301, so as to control the airflow into the high temperature channel 110.
[0056] In some embodiments, the switching module 700 includes a second electromagnetic control valve 702 disposed in the bypass pipe 500. The second electromagnetic control valve 702 is used to control the connection between the low-temperature channel 210 and the first input terminal 301 to control the airflow into the low-temperature channel 210.
[0057] In some embodiments, the control signals of the temperature sensor, the first electromagnetic control valve 701, and the second electromagnetic control valve 702 are connected to the vehicle control unit. The vehicle control unit can receive the temperature signal transmitted by the temperature sensor in real time, and make a judgment based on the signal, and send control signals to the first electromagnetic control valve 701 and the second electromagnetic control valve 702 to control the opening and closing of the first electromagnetic control valve 701 and the second electromagnetic control valve 702.
[0058] In some embodiments, a first temperature threshold is defined as T1, and a second temperature threshold is defined as T2. When T1 < T2, the system is set to a low-temperature operating condition; when T1 ≤ T ≤ T2, the system is set to a normal operating condition; and when T > T2, the system is set to a high-temperature operating condition. Typically, T1 can be set to 200°C, and T2 can be set to 450°C.
[0059] In the above technical solution, when the temperature sensor detects that the airflow temperature T is less than T1, that is, when the airflow temperature is below 200℃ and it is in a low-temperature condition, the vehicle control unit controls the first electromagnetic control valve 701 to close and the second electromagnetic control valve 702 to open. The low-temperature airflow enters the inner pipe 400 from the first input end 301 through the bypass pipe 500, is purified by the second processing device 230, and is finally discharged through the outlet pipe 600.
[0060] When the temperature sensor detects that the temperature T is between T1 and T2, that is, when the airflow temperature is between 200℃ and 450℃, which is under normal operating conditions, the vehicle control unit controls the opening of the first electromagnetic control valve 701 to 50% and the opening of the second electromagnetic control valve 702 to 50%. At this time, the exhaust gas passes through the high-temperature channel 110 and the low-temperature channel 210 respectively, and is purified by the first treatment device 130 and the second treatment device 230, and finally discharged through the exhaust pipe 600.
[0061] When the temperature sensor detects that the airflow temperature T is greater than T2, that is, when the airflow temperature is higher than 450℃ and it is in a high-temperature condition, the vehicle control unit controls the first electromagnetic control valve 701 to open and the second electromagnetic control valve 702 to close. The exhaust gas enters the high-temperature channel 110 of the outer pipe 300 from the first input end 301, and is purified by the first processing device 130, and finally discharged through the exhaust pipe 600.
[0062] In some embodiments, refer to Figure 4 and Figure 5 The high-temperature treatment component 100 includes a swirl plate 140, which is located between the first spray nozzle 120 and the first treatment device 130. The swirl plate 140 is used to induce the high-temperature airflow to form a swirl, so that the urea aqueous solution is refined and evenly dispersed into the high-temperature airflow under the action of centrifugal force, which facilitates the improvement of the subsequent catalytic reduction rate.
[0063] In some embodiments, the swirl plate 140 includes a fixing ring 141, which is sleeved on the inner tube 400 and the outer peripheral wall of the fixing ring 141 is fixedly connected to the inner wall of the outer tube 300. The fixing ring 141 has a plurality of communication ports 143 for high-temperature airflow to pass through. In some embodiments, the swirl plate 140 further includes a guide plate 142, and a plurality of guide plates 142 are respectively provided on the side of each communication port 143 near the first processing device 130.
[0064] In some embodiments, the connecting ports 143 are spaced circumferentially along the fixing ring 141, and the guide plates 142 rotate and tilt radially from the side away from the inner tube 400 toward the axis of the inner tube 400 along the fixing ring 141. The guide plates 142 rotate clockwise or counterclockwise as a whole, so that the mixed airflow passing through the connecting ports 143 rotates along the rotation direction of the guide plates 142 and spirals forward along the axis of the outer tube 300, thereby making the mixing of urea aqueous solution and high-temperature airflow more uniform; at the same time, the swirling flow improves gas-liquid heat transfer, thereby increasing the hydrolysis reaction rate of urea aqueous solution, and the generated ammonia gas is concentrated toward the axis under the action of the swirling flow, effectively reducing the local ammonia gas escape, thereby improving the reduction reaction efficiency.
[0065] In some embodiments, the high-temperature treatment assembly 100 further includes a flow equalization plate 150, which is located on the side of the swirl plate 140 away from the first spray nozzle 120. The flow equalization plate 150 is sleeved on the inner tube 400, and the outer peripheral wall of the flow equalization plate 150 is fixedly connected to the inner wall of the outer tube 300. The flow equalization plate 150 has a plurality of connecting holes 160. When the mixed airflow passes through the flow equalization plate 150, part of the mixed airflow impacts the flow equalization plate 150, causing this part of the mixed airflow to abruptly change its flow direction and mix into the airflow newly arriving at the outer wall of the flow equalization plate 150, thereby making the urea aqueous solution more evenly distributed in the high-temperature airflow. Part of the mixed airflow continues to move towards the first treatment device 130 through the connecting holes 160, reducing the volume of high-temperature gas processed and purified by the first treatment device 130, thereby increasing the contact area between this part of the high-temperature gas and the catalyst disposed in the first treatment device 130, and thus improving the catalytic reaction efficiency of the high-temperature gas.
[0066] In some embodiments, refer to Figure 3 and Figure 4 The cryogenic treatment assembly 200 includes a diverter 240 disposed in the inner tube 400, located between the second spray nozzle 220 and the second treatment device 230, and the diverter 240 is used to divert cryogenic gas.
[0067] In some embodiments, the diverter 240 consists of three intersecting snowflake-shaped plates arranged along the length of the inner tube 400. Each snowflake-shaped plate has its opposite side walls fixedly connected to the inner wall of the inner tube 400, and the overall cross-section of the diverter 240 is hexagonal snowflake-shaped. When the low-temperature mixed gas flow passes through the diverter 240, the urea solution droplets are repeatedly cut, effectively reducing the droplet size. That is, the originally large urea solution droplets are divided into many smaller droplets by the snowflake plates, resulting in more uniform mixing in the low-temperature mixed gas flow and a shorter distance for complete decomposition of the urea solution, thereby improving the efficiency of the subsequent reduction reaction. Simultaneously, the low-temperature mixed gas flow is divided into micro-streams, resulting in a smaller temperature difference within the low-temperature mixed gas flow, thus improving the decomposition efficiency of the urea solution in the low-temperature mixed gas flow and further improving the efficiency of the subsequent reduction reaction. Finally, the structural design of the diverter 240 causes the droplets to converge towards the axis of the inner tube 400, thereby reducing the amount of deposits on the inner circumferential wall of the inner tube 400 and improving the reduction reaction efficiency of the low-temperature gas flow.
[0068] In some embodiments, refer to Figure 4 The first processing device 130 includes a first purification unit 131, which is used to carry a high-temperature catalyst. The high-temperature catalyst is usually selected from styrene-based (V2O5-WO3 / TiO2).
[0069] In some embodiments, the first processing device 130 includes a first heat insulation component, which is used to block the heat transfer generated by the high-temperature airflow reaction, thereby reducing the heat dissipation to the outside through the outer pipe 300, which would cause the reaction temperature in the first purification unit to decrease and reduce the reduction reaction efficiency; at the same time, the first heat insulation component is used to block the heat transfer to the inner pipe 400, thereby protecting the second processing device 230 and reducing the impact of the high temperature in the first purification unit 131 on the low-temperature airflow in the second processing device 230.
[0070] In some embodiments, the first heat insulation component includes a first gasket 132, which is located on the side of the first purification unit near the inner wall of the outer tube 300. The first gasket 132 surrounds the first purification unit and is fixedly connected to the inner wall of the outer tube 300. The first gasket 132 is used to isolate the outer tube 300 from the first purification unit, thereby reducing the temperature of the outer tube 300 to below 200°C and preventing burns to the outer wall; at the same time, it can prevent the carrier of the first purification unit from directly rubbing against the outer tube 300, reducing wear.
[0071] In some embodiments, the first heat insulation component includes a second gasket 133. The second gasket 133 is located near the outer wall of the inner tube 400 on the side of the first purification unit. The second gasket 133 is disposed around the outer wall of the inner tube 400 and is fixedly connected to the outer peripheral wall of the inner tube 400. The second gasket 133 is used to isolate the first purification unit from the second processing device 230 in the inner tube 400, thereby preventing the heat in the first purification unit from affecting the low-temperature gas flow reduction reaction in the second processing device 230. At the same time, the second gasket 133 can coordinate and compensate for the assembly tolerances between the first purification unit 131 and the second processing device 230, facilitating production and installation.
[0072] In some embodiments, the second processing device 230 includes a second purification unit 231, which is used to carry a low-temperature catalyst. The low-temperature catalyst is selected as copper-based (Cu-SAPO-34), wherein SAPO-34 is a molecular sieve framework and copper ions are the catalytic reaction engine, which can ignite at 120°C, expand the temperature range of the low-temperature reaction, and thus have a significant purification effect on the purification of low-temperature gas emissions such as cold start.
[0073] In some embodiments, the second processing device 230 includes a second heat insulation member for blocking the low-temperature airflow from reacting with the heat of the second purification unit 231. The second heat insulation member includes a third gasket 232, which is located between the second purification unit and the inner wall of the inner tube 400. The third gasket 232 is disposed around the second purification unit and is fixedly connected to the inner peripheral wall of the inner tube 400. The third gasket 232 is used to protect the second purification unit 231 and further reduce the influence of the first purification unit on the catalyst in the second purification unit.
[0074] In some embodiments, the core layers of the first gasket 132, the second gasket 133, and the third gasket 232 are all made of ceramic fiber material. The ceramic fiber material can effectively resolve the difference in expansion between the outer tube 300 and the inner tube 400 at high temperatures, and at the same time, it acts as a barrier layer to block the corrosion of the metal shell by urea, sulfides, ammonium salts, etc., thereby increasing its service life.
[0075] In addition, this application also provides an exhaust assembly, which includes an exhaust pipe and a selective catalytic reduction catalyst connected to the exhaust pipe so that the exhaust gas discharged from the exhaust pipe can be purified by the selective catalytic reduction catalyst, and the reduced gas is then discharged into the outside atmosphere through the exhaust pipe.
[0076] Furthermore, this application also provides a vehicle including a chassis, on which the aforementioned exhaust assembly is mounted. A lifting structure is also provided on the chassis, comprising a frame connecting plate, a flexible hanger rod, a hanger lug welding seat, and bolts. The frame connecting plate is located on the ground-facing side of the chassis, and the flexible hanger rod is positioned between the frame connecting plate and the hanger lug welding seat to connect them. A selective catalytic reduction catalyst is fixedly connected to the hanger lug welding seat to be secured to the chassis.
[0077] Because the temperature stability at the turbine outlet and exhaust pipe tail is poor, and the temperature difference range exceeds the catalytic reaction temperature range of the selective catalytic reduction catalyst during vehicle start-up and driving, the reduction reaction efficiency is low and cannot meet emission treatment requirements. Therefore, the lifting structure is usually set in the middle of the exhaust pipe, that is, the selective catalytic reduction catalyst is usually located in the middle of the exhaust pipe. At the same time, it is at the active temperature of the catalyst, which can also reduce the risk of damage to the selective catalytic reduction catalyst from external forces and facilitate replacement and maintenance.
[0078] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.
Claims
1. A selective catalytic reduction catalyst, characterized in that, It includes: High-temperature treatment component (100) and low-temperature treatment component (200); The high-temperature processing component (100) includes: High-temperature channel (110) is used for high-temperature airflow; A first processing device (130) is used to purify the high-temperature airflow, and the first processing device (130) is located in the high-temperature channel (110); The cryogenic treatment assembly (200) includes; A low-temperature channel (210) is used for the passage of low-temperature gas. One end of the low-temperature channel (210) passes through the side wall of the high-temperature channel (110) and is embedded in the high-temperature channel (110). The second processing device (230) is used to purify the low-temperature gas and is located in the low-temperature channel (210).
2. The selective catalytic reduction catalyst according to claim 1, characterized in that, include: An outer tube (300), one end of which is a first input terminal (301); An inner tube (400) is disposed inside the outer tube (300), one end of the inner tube (400) is a second input end (401), and the second input end (401) is connected to the inner wall of the first input end (301); A bypass pipe (500) connects the first input terminal (301) and the second input terminal (401); The high-temperature channel (110) is formed between the inner tube (400) and the outer tube (300); The inner tube (400) contains the low-temperature channel (210); A switching module (700) is used to turn the high-temperature channel (110) and the low-temperature channel (210) on or off.
3. The selective catalytic reduction catalyst according to claim 2, characterized in that, The high-temperature processing component (100) includes: A first spray nozzle (120) is connected to the side wall of the high-temperature channel (110) and is used to spray a reducing solvent into the high-temperature channel (110). A swirl plate (140) is located between the first spray nozzle (120) and the first processing device (130), and the swirl plate (140) is used to induce the high-temperature airflow to form a swirl.
4. The selective catalytic reduction catalyst according to claim 3, characterized in that, The swirl plate (140) includes: A fixing ring (141) is located between the inner tube (400) and the outer tube (300), and the fixing ring (141) has a communication port (143); A guide plate (142) is located on the side of the communication port (143) near the first processing device (130). The guide plate (142) is used to change the movement pattern of the high-temperature airflow.
5. The selective catalytic reduction catalyst according to claim 3, characterized in that, The high-temperature processing assembly (100) further includes a flow equalization plate (150), which is located on the side of the swirling plate (140) away from the first spray nozzle (120). The flow equalization plate (150) is located between the inner tube (400) and the outer tube (300). The flow equalization plate (150) has a plurality of connecting holes (160) for dispersing and mixing the high-temperature airflow.
6. The selective catalytic reduction catalyst according to claim 2, characterized in that, The cryogenic treatment assembly (200) includes: The second spray nozzle (220) penetrates the side wall of the high temperature channel (110) and communicates with the low temperature channel (210); A diverter (240) is disposed in the inner tube (400) between the second spray nozzle (220) and the second processing device (230), and the diverter (240) is used to divert the cryogenic gas.
7. The selective catalytic reduction catalyst according to claim 1, characterized in that, The first processing device (130) includes: The first purification unit (131) is used to support the high-temperature catalyst; The first heat insulation element is used to block the heat transfer generated by the reaction of the high-temperature airflow.
8. The selective catalytic reduction catalyst according to claim 1, characterized in that, The second processing device (230) includes: The second purification unit (231) is used to support the low-temperature catalyst; The second heat insulation component is used to block the low-temperature airflow from reacting with the heat of the second purification unit (231).
9. An exhaust assembly, characterized in that, It includes a selective catalytic reduction catalyst as described in any one of claims 1 to 8, the exhaust assembly including an exhaust pipe, the selective catalytic reduction catalyst being connected to the exhaust pipe for purifying the treated gas.
10. A vehicle, characterized in that, The system includes a chassis on which an exhaust assembly as described in claim 9 is mounted, and the chassis also includes a lifting structure for mounting the selective catalytic reduction catalyst.