Tail gas after-treatment device and method
By setting inner and outer air intake pipes and exhaust valves in the exhaust gas aftertreatment device, the flow path of exhaust gas is dynamically adjusted, which solves the problem of low catalytic efficiency of traditional devices under different operating conditions, and achieves efficient pollutant conversion and catalyst life extension.
Patent Information
- Application Number
- CN202511732770.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-24
- Publication Date
- 2026-02-10
AI Technical Summary
Traditional exhaust aftertreatment devices have low catalytic efficiency under different engine operating conditions and cannot dynamically adapt to changes in exhaust flow, resulting in decreased efficiency at high loads or failure to meet emission standards at low loads.
By incorporating inner and outer intake pipes and exhaust valves in the exhaust aftertreatment device, the flow path of the exhaust gas is dynamically adjusted to ensure that the catalyst maintains high conversion efficiency under various operating conditions. Specific measures include increasing the flow rate of the inner intake pipe under high load and reducing or closing the flow rate of the inner intake pipe under low load, and optimizing airflow distribution and thermal management using a split chamber.
It significantly improved pollutant conversion rate, extended catalyst lifespan, and optimized thermal management, achieving highly efficient catalytic reactions under different operating conditions.
Smart Images
Figure CN121497461A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of engine technology, specifically relating to an exhaust gas aftertreatment device and method. Background Technology
[0002] With increasing global emphasis on environmental protection, regulations on exhaust emissions from motor vehicles and non-road mobile machinery are becoming increasingly stringent. Hydrocarbons (HC), as one of the major pollutants, require efficient purification, which is a core objective of after-treatment systems. Methanol oxidation catalysts (MOCs) catalyze reactions to oxidize CO (carbon monoxide), HC (hydrocarbons), and soluble organic compounds (SOF) in exhaust gases into water and carbon dioxide.
[0003] The catalytic performance of MOCs is highly dependent on their operating environment, with space velocity (GHSV) being a crucial parameter. Space velocity is defined as the volume of gas flowing through a unit volume of catalyst per hour, directly determining the contact time between exhaust gas and the active sites of the catalyst. Existing MOC catalysts are typically designed to operate within an optimal space velocity window, within which HC conversion efficiency is highest. However, in real-world applications, engine loads are dynamically changing, ranging from low idle speed to high power output, resulting in a wide range of exhaust flow rates. This broad range of exhaust flow rates directly leads to significant fluctuations in space velocity flowing through a fixed volume of catalyst bed. When the engine is under low load, excessively low space velocity may result in insufficient heat accumulation for the reaction, affecting low-temperature activity; conversely, when the engine is under high load, the space velocity significantly exceeds the catalyst's optimal design range, causing the exhaust gas to have an excessively short residence time in the catalyst bed. HC molecules fail to fully contact the active sites before being expelled, resulting in a sharp drop in conversion efficiency and failure to meet stringent emission standards.
[0004] Existing aftertreatment system designs typically employ fixed-size and fixed-volume MOC (Metal-Oxide-Catalyst) reaction chambers. This is a passive design, the core idea of which is to select the catalyst volume based on the engine's calibration conditions or maximum expected flow rate, aiming to achieve compliance under most operating conditions. However, an inherent drawback of this approach is its inability to dynamically adapt to changes in exhaust flow rate across the entire engine operating range. To ensure treatment efficiency at high loads, it may be necessary to increase the catalyst volume, but this leads to increased system cost, size, and back pressure (detrimental to engine performance); while meeting only low-load requirements will inevitably result in runaway emissions at high loads. Therefore, this "static" design approach presents a dilemma of balancing performance and cost when dealing with dynamically changing engine operating conditions.
[0005] Therefore, there is an urgent need to provide an exhaust gas aftertreatment device and control method to solve the above problems. Summary of the Invention
[0006] The objective of this invention is to at least solve the problem of low catalytic efficiency in traditional exhaust aftertreatment devices under different engine operating conditions. This objective is achieved through the following technical solution: A first aspect of the present invention provides an exhaust gas aftertreatment device, comprising: A housing containing a catalyst; An air intake pipe, comprising an outer air intake pipe and an inner air intake pipe, wherein the outer air intake pipe communicates with the interior of the housing, and the inner air intake pipe passes through the outer air intake pipe; An exhaust valve is disposed inside the inner air intake pipe and is used to adjust the air intake flow rate of the inner air intake pipe. The flow divider is located inside the housing. The outlet of the inner air inlet pipe is connected to the flow divider, and the exhaust gas from the inner air inlet pipe flows to the catalyst through the flow divider.
[0007] The exhaust gas aftertreatment device proposed in this technical solution actively controls the exhaust gas space velocity by adjusting the opening of the exhaust valve, thereby ensuring that the catalyst can maintain a high conversion efficiency under various engine operating conditions. Space velocity, which is the volume of exhaust gas processed per unit volume of catalyst per unit time, is a key parameter for evaluating the performance of a catalytic reactor. Excessive space velocity means that the contact time between the exhaust gas and the catalyst is too short, and reactant molecules are discharged before they can complete conversion at the active sites, leading to a sharp drop in efficiency. Insufficient space velocity, while ensuring sufficient contact, limits the amount of gas processed per unit time and may cause imbalances in system thermal management. Traditional aftertreatment devices have their space velocity entirely determined by the engine's exhaust volume and cannot be adaptively adjusted, resulting in a narrow high-efficiency operating window. This technical solution effectively solves these problems. Specifically, when the engine is running under high load, the intake airflow increases significantly. At this time, increasing the exhaust valve opening allows a larger proportion of the exhaust gas to enter the split chamber through the inner intake pipe and ultimately flow to the catalyst. The structure of the split chamber optimizes and increases the effective contact area between the exhaust gas flow field and the catalyst support, enabling the catalyst to participate in the reaction more efficiently. Conversely, when the engine is operating under low load (such as cold start or idling), the intake airflow is small, reducing the opening of the exhaust valve or even closing it completely. At this time, most, if not all, of the exhaust gas is guided through the outer intake manifold into the housing cavity. This flow path design allows the already low-temperature exhaust gas to have a large-area, low-velocity contact with the entire frontal surface of the catalyst. This not only minimizes heat loss and utilizes the limited exhaust gas thermal energy to quickly heat the catalyst to its ignition temperature, but more importantly, it forces the exhaust gas to contact the entire catalyst cross-section at low flow rates, avoiding the problem of stagnation in only a few channels due to excessively low flow rates. This effectively maintains the necessary reaction space velocity, ensuring the full catalytic reaction. In summary, this solution dynamically distributes the exhaust gas flow path through exhaust valve adjustment, maintaining the space velocity at the window of highest catalyst activity regardless of whether the engine is operating under low or high load conditions. This significantly improves the overall conversion rate of pollutants (such as HC and NOx) and extends the catalyst's lifespan through optimized thermal management and flow distribution, achieving a dual leap in efficiency and environmental performance.
[0008] In addition, the exhaust gas aftertreatment device of the present invention may also have the following additional technical features: In some embodiments of the present invention, the side wall of the diversion chamber is provided with a communication port.
[0009] In some embodiments of the present invention, the cross-sectional area of the inner air intake pipe is half that of the cross-sectional area of the outer air intake pipe.
[0010] In some embodiments of the present invention, a detection unit is provided on the air intake pipe, and the detection unit is used to detect the air intake flow rate.
[0011] In some embodiments of the present invention, a flow divider is provided inside the inner air intake pipe, the flow divider is located downstream of the exhaust valve, and the flow divider is provided with a plurality of air intake holes.
[0012] In some embodiments of the present invention, the interior of the housing is provided with a plurality of supports for placing the catalyst.
[0013] In some embodiments of the present invention, the housing includes an outer shell and an inner shell, the inner shell being disposed inside the outer shell, and thermal insulation cotton being filled between the inner shell and the outer shell.
[0014] In some embodiments of the present invention, the outer wall of the inner shell is provided with a reinforcing portion.
[0015] In some embodiments of the present invention, the area of the side of the catalyst facing the split chamber is twice the cross-sectional area of the split outlet.
[0016] In a second aspect of the invention, a method for exhaust gas aftertreatment is provided, wherein the exhaust gas aftertreatment device control method is applied to the aforementioned exhaust gas aftertreatment device, the exhaust gas aftertreatment method comprising: When the engine is under high load, the exhaust valve is fully opened; When the engine is under low load, the exhaust valve is closed. Attached Figure Description
[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic diagram of the exhaust gas aftertreatment device according to an embodiment of the present invention is shown. Figure 2 A schematic cross-sectional view of the exhaust gas aftertreatment device according to an embodiment of the present invention is shown in the vertical direction. Figure 3 A schematic cross-sectional view of the exhaust gas aftertreatment device according to an embodiment of the present invention is shown in the horizontal direction. Figure 4 A partial structural schematic diagram of an exhaust gas aftertreatment device according to an embodiment of the present invention is shown.
[0018] The labels in the attached diagram are as follows: 100. Housing; 110. Air inlet; 120. Cavity; 130. Air outlet; 140. Bracket; 150. Outer shell; 160. Inner shell; 170. Reinforcing section; 200. Intake pipe; 210. Outer intake pipe; 220. Inner intake pipe; 230. Split plate; 300. Exhaust valve; 400, Diversion chamber; 410, Diversion inlet; 420, Diversion cavity; 430, Diversion outlet; 440, Connecting port; 450, Support pipe; 500. Catalyst; 600. Exhaust pipe. Detailed Implementation
[0019] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
[0020] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.
[0021] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.
[0022] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations.
[0023] Figure 1 A schematic diagram of the exhaust gas aftertreatment device according to an embodiment of the present invention is shown. Figure 2 A schematic cross-sectional view of the exhaust gas aftertreatment device according to an embodiment of the present invention is shown in the vertical direction. Figure 3 A schematic cross-sectional view of the exhaust gas aftertreatment device according to an embodiment of the present invention is shown in the horizontal direction. Figure 4 A partial structural schematic diagram of an exhaust gas aftertreatment device according to an embodiment of the present invention is shown. Figures 1 to 4 As shown, the present invention proposes an exhaust gas aftertreatment device, including a housing 100, an intake pipe 200, an exhaust valve 300, and a diversion chamber 400; wherein, a catalyst 500 is placed inside the housing 100; the intake pipe 200 includes an outer intake pipe 210 and an inner intake pipe 220, the outer intake pipe 210 being connected to the interior of the housing 100, and the inner intake pipe 220 passing through the outer intake pipe 210; the exhaust valve 300 is disposed inside the inner intake pipe 220, and the exhaust valve 300 is used to adjust the intake flow rate of the inner intake pipe 220; the diversion chamber 400 is located inside the housing 100, the outlet end of the inner intake pipe 220 is connected to the diversion chamber 400, and the exhaust gas from the inner intake pipe 220 flows to the catalyst 500 through the diversion chamber 400.
[0024] The exhaust gas aftertreatment device proposed in this technical solution actively controls the exhaust gas space velocity by adjusting the opening of the exhaust valve 300, thereby ensuring that the catalyst 500 can maintain a high conversion efficiency under various engine operating conditions. Space velocity, i.e., the volume of exhaust gas processed per unit volume of catalyst 500 per unit time, is a key parameter for evaluating the performance of the catalytic reactor. Excessive space velocity means that the contact time between the exhaust gas and the catalyst 500 is too short, and reactant molecules are discharged before completing conversion at the active sites, leading to a sharp drop in efficiency. Insufficient space velocity, while ensuring sufficient contact, limits the amount of gas processed per unit time and may cause imbalances in system thermal management. Traditional aftertreatment devices have their space velocity entirely determined by the engine exhaust volume and cannot be adaptively adjusted, resulting in a narrow high-efficiency operating window. This technical solution effectively solves these problems. Specifically, when the engine is running under high load, the intake airflow increases significantly. At this time, increasing the opening of the exhaust valve 300 allows a larger proportion of exhaust gas to enter the diversion chamber 400 through the inner intake pipe 220 and ultimately flow to the catalyst 500. The structure of the split chamber 400 optimizes and increases the effective contact area between the exhaust gas flow field and the catalyst 500, enabling the catalyst 500 to participate in the reaction more efficiently. Conversely, when the engine is operating under low load (such as cold start or idling), the intake air flow is small, reducing the opening of the exhaust valve 300 or even closing it completely. At this time, most or even all of the exhaust gas is guided through the outer intake pipe 210 and enters the interior of the housing 100. This flow path design allows the already low-temperature exhaust gas to have a large-area, low-velocity contact with the entire frontal surface of the catalyst 500. This not only minimizes heat loss and utilizes the limited exhaust gas thermal energy to quickly heat the entire catalyst 500 to the ignition temperature, but more importantly, it forces the exhaust gas to contact the entire cross-section of the catalyst 500 at low flow rates, avoiding the problem of stagnation in only a few channels due to excessively low flow rates. This effectively maintains the necessary reaction space velocity, ensuring the full catalytic reaction. In summary, this solution dynamically distributes the flow path of exhaust gas by adjusting the exhaust valve 300. Regardless of whether the operating conditions are low or high, the space velocity can be maintained at the window of highest activity of the catalyst 500, thereby significantly improving the overall conversion rate of pollutants (such as HC and NOx). By optimizing thermal management and flow distribution, the service life of the catalyst 500 is extended, achieving a double leap in efficiency and environmental performance.
[0025] See also Figure 1The shell 100 is generally rectangular, with both the inner intake pipe 220 and the outer intake pipe 210 being cylindrical. The shell 100 has an intake port 110, a cavity 120, and an outlet 130 connected sequentially. The outlet end of the outer intake pipe 210 is connected to the intake port 110, and the outlet 130 of the shell 100 is connected to an outlet pipe 600. The outlet pipe 600 is cylindrical and coaxially arranged with the inner intake pipe 220. Exhaust gas enters the interior of the shell 100 through the outer intake pipe 210 or the inner intake pipe 220, flows through the catalyst 500, reacts, and is discharged through the outlet pipe 600. Optionally, the cross-sectional area of the front end of the diversion chamber 400 gradually increases, and the rear end of the diversion chamber 400 is generally rectangular. Optionally, the exhaust valve 300 has a circular, plate-like structure and is rotatably mounted inside the inner intake pipe 220. The exhaust valve 300 can be closed and opened by rotating it. Optionally, in some embodiments, the exhaust valve 300 can also be located inside the exhaust pipe 600, achieving the same purpose of adjusting airspeed.
[0026] Furthermore, the diversion chamber 400 has a diversion inlet 410, a diversion cavity 420 and a diversion outlet 430 connected in sequence. The outlet end of the inner inlet pipe 220 is connected to the diversion inlet 410, and the diversion outlet 430 faces the catalyst 500.
[0027] Furthermore, the side wall of the diversion chamber 400 is provided with a connecting port 440.
[0028] The connection port 440 serves to balance airflow and pressure. When the exhaust valve 300 is closed, the pressure inside the distribution chamber 400 is low. At this time, some of the airflow from the outer cavity 120 via the catalyst 500 is drawn into the distribution chamber 420 through the connection port 440 on the side wall. This process helps balance the pressure difference between the distribution chamber 400 and the outer cavity 120, preventing structural vibration or noise due to excessive pressure difference. When the exhaust valve 300 is closed, exhaust gas can enter the distribution chamber 400 through the connection port 440, thereby providing uniformity of airflow around the distribution chamber 420, making the reaction more efficient. Secondly, the connection port 440 can guide airflow mixing. When the exhaust valve 300 is open, the airflow entering the distribution chamber 400 from the connection port 440 mixes with the airflow from the inner intake pipe 220 around the distribution chamber 420. This mixing makes the airflow distribution more uniform, increases the effective area of the catalyst 500, and helps improve the efficiency of subsequent reactions on the catalyst 500.
[0029] Preferably, the connecting port 440 is located at one end of the flow distribution chamber 420 near the reaction surface of the catalyst 500. Compared to a location in the middle of the flow distribution chamber 420 or far from the catalyst 500, this configuration provides a significant performance improvement. This arrangement allows the airflow to be most effectively intervened and optimized upon reaching the catalyst 500, effectively improving the uniformity of airflow distribution and thermal management, thereby ultimately achieving higher catalyst 500 conversion efficiency and a longer catalyst 500 lifespan.
[0030] Optionally, multiple connecting ports 440 are provided on each of the four walls at the rear end of the flow divider 420, and the multiple connecting ports 440 are arranged in a rectangular array. Optionally, the connecting ports 440 are circular holes. It is understood that the number and size of the connecting ports 440 should be set according to the usage requirements to ensure balanced airflow distribution, appropriate flow resistance and back pressure, while ensuring structural strength and durability.
[0031] Furthermore, the cross-sectional area of the inner air intake pipe 220 is half the cross-sectional area of the outer air intake pipe 210.
[0032] The ratio of the cross-sectional area of the inner intake pipe 220 and the outer intake pipe 210 needs to be rationally set, as this ratio directly affects the performance of the device under different operating conditions. The cross-sectional area of the intake pipe 200 directly determines its ability to allow gas to pass through. The smaller the area, the greater the flow resistance. By setting the ratio of the cross-sectional area of the inner intake pipe 220 and the outer intake pipe 210, the maximum flow distribution capacity of the two flow paths when the exhaust valve 300 is fully open can be preset. If the ratio of the cross-sectional area is too large, the area of the inner pipe will be too large, resulting in excessive flow when the exhaust valve 300 is fully open, which will reduce its injection speed and decrease the ability of the airflow to impact the catalyst 500; if the ratio of the cross-sectional area is too small, its effect will be negligible. A ratio of 1:2 is a compromise and an effective balance point.
[0033] Furthermore, a detection unit is provided on the intake pipe 200, which is used to detect the intake air flow.
[0034] Optionally, the detection unit can be a flow sensor, such as a hot-wire hot-film air flow sensor or a manifold absolute pressure sensor. Optionally, a pressure sensor or temperature sensor can also be installed on the intake pipe 200, and the pressure signal and temperature signal can be transmitted to the control unit, which can then adjust the opening of the exhaust valve 300 according to the intake air flow.
[0035] Further, see Figure 4 The inner intake pipe 220 has a flow divider 230 inside, which is located downstream of the exhaust valve 300. The flow divider 230 has multiple air intake holes.
[0036] The main function of the flow divider 230 is to rectify and equalize the flow. When exhaust gas enters the inner intake pipe 220 and flows through the exhaust valve 300, it generates a high-speed, turbulent, and uneven jet. This airflow may concentrate on one side of the pipe or generate strong eddies and turbulence. Without the flow divider 230, the airflow is prone to causing noise and vibration, and the airflow cannot evenly cover the surface of the catalyst 500, greatly reducing the reaction efficiency. By setting the flow divider 230, it disperses the turbulent airflow into multiple small, stable jets. These small jets mix with each other after passing through the intake holes and re-converge within a certain distance behind the flow divider 230, forming an airflow with a more uniform velocity and more stable flow (higher degree of laminarization). At the same time, the flow divider 230 decomposes the concentrated, high-energy eddies into dispersed, low-energy eddies. The small eddies have a higher frequency but lower energy and are more easily attenuated in the air, thus effectively suppressing airflow noise. Furthermore, the stable airflow also reduces vibration in the duct and the diversion chamber 400.
[0037] Furthermore, the interior of the housing 100 is provided with a plurality of supports 140 for placing the catalyst 500.
[0038] In this technical solution, each unit contains 4 blocks of the three-dimensional catalyst, i.e., 4*3*2=24 blocks. In other technical solutions, the number of catalyst blocks can be 4*3*3=36 blocks or 4*2*2=16 blocks. Optionally, the support 140 includes 3 sets of trusses arranged vertically, with two trusses in each set. The two trusses in each set are spaced apart, and the catalyst 500 is supported at both ends by the two trusses respectively.
[0039] Furthermore, the housing 100 includes an outer shell 150 and an inner shell 160, with the inner shell 160 disposed inside the outer shell 150, and thermal insulation cotton filling the space between the inner shell 160 and the outer shell 150.
[0040] First, the primary purpose of this structural design is to achieve excellent thermal insulation. The inner shell 160 directly contacts the high-temperature exhaust gases, and the insulation cotton filling between the inner shell 160 and the outer shell 150 effectively blocks heat, greatly inhibiting heat transfer to the outer shell 150 through conduction and convection. This allows the cavity 120 inside the shell 100, especially the catalyst 500, to maintain a high operating temperature for extended periods. This is crucial for the daily operation of the vehicle, especially under conditions of frequent start-stop or low-speed driving, effectively preventing the catalyst 500 temperature from dropping below its ignition temperature (typically 250-300°C), thus avoiding catalyst failure and ensuring its continuous and efficient purification of exhaust pollutants. Second, this design also brings the additional benefits of protecting external components and improving driving safety. The surface temperature of the outer shell 150 is significantly reduced due to the insulation layer, effectively preventing burns to maintenance personnel or ignition of nearby automotive parts such as wiring harnesses and plastic components. Meanwhile, uniform insulation can reduce thermal stress caused by excessive temperature difference between the inside and outside of the shell 100, which helps to improve the structural reliability and long-term durability of the entire device. Optionally, the insulation cotton can be made of high-performance thermal insulation materials such as ceramic fiber. Optionally, the two ends of the inner shell 160 are respectively connected to the inner air inlet pipe 220 and the air outlet pipe 600.
[0041] Furthermore, the outer wall of the inner shell 160 is provided with a reinforcing part 170.
[0042] Optionally, the reinforcing part 170 is a plate-like structure bent into a U-shape. The function of the reinforcing part 170 is to enhance the structural rigidity and strength of the inner shell 160 and even the entire shell 100, thereby coping with the severe challenges faced by the exhaust aftertreatment device under complex operating conditions. Specifically, the reinforcing part 170 can enhance the shell 100's ability to resist internal pressure and impact. The high-temperature exhaust gas discharged from the engine has pressure pulsations, especially during transient engine conditions (such as acceleration and deceleration), which may generate a certain impact force. The reinforcing part 170 can effectively prevent the inner shell 160 from expanding and contracting or cracking under internal pressure, ensuring the sealing and integrity of the structure. Furthermore, the reinforcing part 170 can improve the shell 100's ability to withstand external vibration and load. When the vehicle is driving on bumpy roads, the entire aftertreatment system will be subjected to severe vibration and impact from the chassis. In addition, it may be subjected to unexpected mechanical loads during assembly, handling, or maintenance. The reinforcement 170 can distribute these stresses to a larger area, avoiding stress concentration that could lead to localized cracking or fatigue damage to the inner shell 160, thus greatly improving the product's durability and reliability.
[0043] Optionally, the reinforcing portion 170 can be an annular rib surrounding the outer wall of the inner shell 160, a longitudinal rib distributed along the axial direction of the shell 100, or a mesh structure formed by combining both. This arrangement can reduce material usage and maximize the bending and torsional stiffness of the shell 100. Optionally, the reinforcing portion 170 can also be multiple protrusions or grooves formed on the outer wall of the inner shell 160 by a stamping process. In this embodiment, the reinforcing portion 170 is arranged circumferentially along the inner shell 160, and its cross-section is approximately "U"-shaped. There are multiple reinforcing portions 170, which are spaced apart along the axial direction of the inner shell 160.
[0044] Furthermore, a support tube 450 is provided inside the cavity 120. The support tube 450 is arranged vertically, with its two ends extending from the top and bottom of the diversion chamber 400, respectively, and connected to the reinforcing part 170. The support tube 450 is used to reinforce and support the diversion chamber 400. In addition, the support tube 450 can also serve as a support tube for the soot blowing device.
[0045] Furthermore, the area of the catalyst 500 facing the flow divider 400 (the flow-facing area) is twice the cross-sectional area of the flow divider outlet 430.
[0046] By rationally setting the cross-sectional area of the diversion outlet 430, the exhaust gas treatment device can be guaranteed to have a high waste gas conversion rate under various operating conditions, and the service life of the catalyst 500 can be extended by optimizing the smooth distribution.
[0047] Furthermore, this technical solution also provides an exhaust gas aftertreatment method, which is applied to the aforementioned exhaust gas aftertreatment device. The exhaust gas aftertreatment method includes: When the engine is under high load, the exhaust valve is fully opened at 300°. When the engine is under low load, the exhaust valve 300 is closed.
[0048] The control method provided by this technical solution intelligently switches the flow path of exhaust gas in the exhaust aftertreatment device according to the engine load status, that is, by controlling the full opening and closing of the control valve, it achieves precise response to high and low load conditions. This method fundamentally optimizes the working environment of the catalyst 500, thereby achieving a high-efficiency and stable exhaust gas conversion rate. By closing the exhaust valve 300 when the engine is under low load, the catalytic efficiency and rapid ignition capability under low load conditions are significantly improved. When the engine is under low load, the exhaust temperature is relatively low and the total exhaust flow is small. At this time, closing the exhaust valve 300 forces all exhaust gas into the cavity 120 of the housing 100 through the outer intake pipe 210. This flow path design allows the already low-temperature exhaust gas to have maximum contact area with the catalyst 500, rather than losing heat through the inner intake pipe 220. This allows its core and edge parts to heat up quickly and evenly, rapidly crossing the ignition temperature threshold. This is crucial for reducing the cold start and idling emissions most common in urban driving conditions, directly targeting the weaknesses of traditional aftertreatment systems. Secondly, this control strategy optimizes system performance and catalyst 500 utilization under high-load conditions. When the engine is running at high load, the exhaust flow is large and the temperature is high. The catalyst 500 is already in its efficient operating temperature range. The main challenge at this time is how to handle the large amount of exhaust gas and prevent local overheating. At this time, the exhaust valve 300 is fully opened, and a portion of the high-temperature exhaust gas will be directly sprayed into the central area of the catalyst 500 through the inner intake pipe 220 and the diversion chamber 400. This airflow can not only penetrate deep into the catalyst 500 bed, ensuring that the most difficult pollutants to be converted are thoroughly purified in the core high-temperature area, but also optimize the airflow distribution by mixing with the external airflow introduced by the connecting port 440. This avoids the "short-circuit" risk of the airflow only passing through the edge of the catalyst 500 under high flow conditions, so that the entire catalyst 500 carrier (from the center to the edge) is utilized efficiently. This ensures high conversion rate while also improving system durability and avoiding catalyst 500 sintering deactivation caused by local overheating. Therefore, this control logic based on engine load transforms the exhaust gas aftertreatment device into an intelligent "reactor". It not only ensures a high waste gas conversion rate under various operating conditions, but also extends the catalyst life by optimizing the flow field distribution. It is a superior control strategy that takes into account emission performance, system reliability and cost-effectiveness.
[0049] The efficiency of a certain MOC catalyst 500 in generating NO2 and converting HC was tested using the exhaust gas aftertreatment device control method provided in this technical solution. The results are shown in the table below:
[0050] Under normal operating conditions, the NO2 conversion rate is required to be greater than 70%, and the HC conversion rate greater than 90%. Based on the test results in the table above, when the engine is operating under high load and the exhaust valve is open at 300°, the air velocity is 6 h⁻¹. -1 The NO2 conversion rate is 100%, and the HC conversion rate is 92%. Therefore, in actual operation, when the engine is under high load, exhaust valve 300 is opened; when the engine is under low load, exhaust valve 300 is closed, and the air velocity is 3h. -1 The NO2 conversion rate is 70%, and the HC conversion rate is 99%. Therefore, in actual operation, when the engine is working under low load, the exhaust valve 300 should be closed.
[0051] This can result in higher NO2 and HC conversion rates that meet the requirements; when the engine is operating under low load, closing the exhaust valve 300 can also ensure that the NO2 and HC conversion rates meet the requirements.
[0052] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. A tail gas aftertreatment device, characterized in that, include: A housing (100) containing a catalyst (500). An air intake pipe (200) is provided, comprising an outer air intake pipe (210) and an inner air intake pipe (220). The outer air intake pipe (210) communicates with the interior of the housing (100), and the inner air intake pipe (220) passes through the outer air intake pipe (210). An exhaust valve (300) is disposed inside the inner air intake pipe (220) and is used to adjust the air intake flow rate of the inner air intake pipe (220). The flow divider (400) is located inside the housing (100). The outlet end of the inner air inlet pipe (220) is connected to the flow divider (400). The exhaust gas from the inner air inlet pipe (220) flows to the catalyst (500) through the flow divider (400).
2. The exhaust gas aftertreatment device according to claim 1, characterized in that, The side wall of the diversion chamber (400) is provided with a communication port (440).
3. The exhaust gas aftertreatment device according to claim 1, characterized in that, The cross-sectional area of the inner air intake pipe (220) is half the cross-sectional area of the outer air intake pipe (210).
4. The exhaust gas aftertreatment device according to claim 1, characterized in that, The intake pipe (200) is equipped with a detection unit, which is used to detect the intake flow rate.
5. The exhaust gas aftertreatment device according to claim 1, characterized in that, The inner air intake pipe (220) is provided with a flow divider (230), which is located downstream of the exhaust valve (300). The flow divider (230) is provided with multiple air intake holes.
6. The exhaust gas aftertreatment device according to claim 1, characterized in that, The housing (100) is provided with a plurality of supports (140) inside, which are used to place the catalyst (500).
7. The exhaust gas aftertreatment device according to any one of claims 1-6, characterized in that, The housing (100) includes an outer shell (150) and an inner shell (160), the inner shell (160) being disposed inside the outer shell (150), and thermal insulation cotton being filled between the inner shell (160) and the outer shell (150).
8. The exhaust gas aftertreatment device according to claim 7, characterized in that, The outer wall of the inner shell (160) is provided with a reinforcing part (170).
9. The exhaust gas aftertreatment device according to any one of claims 1-6, characterized in that, The area of the catalyst (500) facing the diversion chamber (400) is twice the cross-sectional area of the diversion outlet (430).
10. A method for exhaust gas aftertreatment, characterized in that, The exhaust gas aftertreatment device applied to any one of claims 1-9, wherein the exhaust gas aftertreatment method comprises: When the engine is under high load, the exhaust valve (300) is fully opened; When the engine is under low load, the exhaust valve (300) is closed.