Exhaust gas intake pipe, exhaust gas recirculation device, and engine

Abstract

The application relates to the field of engines and discloses an exhaust gas intake pipe, an exhaust gas recirculation device and an engine. The exhaust gas intake pipe comprises a pipe body and fin-shaped protrusions arranged on the inner wall of the pipe body; the pipe body comprises an air intake end and an air outlet end which are opposite to each other; the fin-shaped protrusions comprise a bottom surface, a top surface and a flow-encountering surface connecting the bottom surface and the top surface; the flow-encountering surface is located on the side of the fin-shaped protrusion facing the air intake end, and the flow-encountering surface is inclined along the direction from the air intake end to the air outlet end. By arranging the fin-shaped protrusions on the inner wall of the pipe body, the deposition and separation effect of oil and gas particles in the exhaust gas can be improved by means of the flow field regulation.

Description

Technical Field

[0001] This application relates to the field of engine technology, and in particular to an exhaust gas intake pipe, an exhaust gas recirculation device, and an engine. Background Technology

[0002] To meet increasingly stringent emission and thermal efficiency requirements, vehicle engines commonly employ catalytic converters to increase the exhaust gas recirculation (EGR) rate, thereby reducing combustion temperature and nitrogen oxide (NOx) levels. x This method reduces emissions. However, it also leads to a significant increase in the content of oil and gas impurities in the intake passage of the exhaust gas recirculation device. In particular, when the fuel, such as gasoline, is of poor quality and the exhaust gas contains more gum, olefins, and incomplete combustion products, it is very easy to form sludge and soot particles under high temperature conditions.

[0003] Currently, the intake pipe of the exhaust gas recirculation device has a very weak ability to adsorb and capture oil and gas particles. A large number of oil and gas impurities will directly enter the EGR valve body, throttle body and other precision control components with the exhaust gas, causing these key components to quickly accumulate carbon, get stuck or even fail completely, seriously affecting the engine's emission performance, power response and service life, and even causing quality problems. Summary of the Invention

[0004] This application discloses an exhaust gas intake pipe, an exhaust gas recirculation device, and an engine, which improves the deposition and separation effect of oil and gas particles in the exhaust gas while controlling the increase in pipeline flow resistance.

[0005] In a first aspect, embodiments of this application provide an exhaust gas inlet pipe, which includes a pipe body and fin-shaped protrusions disposed on the inner wall of the pipe body; The exhaust gas inlet pipe includes an inlet end and an outlet end that are opposite to each other; the fin-shaped protrusion includes a bottom surface, a top surface, and a flow-facing surface connecting the bottom surface and the top surface; the flow-facing surface is located on the side of the fin-shaped protrusion facing the inlet end, and the flow-facing surface is inclined along the direction from the inlet end to the outlet end.

[0006] The exhaust gas inlet pipe provided in this embodiment improves the deposition and separation of oil and gas particles in the exhaust gas by incorporating fin-shaped protrusions on the inner wall of the pipe body, thereby enhancing the effect of flow field regulation. The fin-shaped protrusions are connected to the inner wall of the pipe body at their bottom surface. A flow-facing surface connecting the bottom and top surfaces is provided on the side facing the inlet end, and this flow-facing surface is inclined along the direction from the inlet end to the outlet end, forming a flow-guiding structure that follows the airflow direction. When the exhaust gas carrying oil and gas particles flows from the inlet end to the outlet end, the airflow can be gradually deflected and lifted along the inclined flow-facing surface, reducing the direct impact between the airflow and the fin-shaped protrusions. This helps control the increase in pipe flow resistance. Simultaneously, the airflow smoothly guided by the flow-facing surface, after passing the fin-shaped protrusions, more easily forms a longitudinal vortex in the area behind the fin-shaped protrusions near the outlet end. This longitudinal vortex actively draws oil and gas particles from the central region of the pipeline towards the pipe wall. Combined with the relatively low flow velocity at the pipe wall, this promotes the deposition of more oil and gas particles on the pipe wall behind the fin-shaped protrusions, thereby improving the removal efficiency of oil and gas particles from the exhaust gas and enhancing exhaust gas purification performance. The exhaust gas inlet pipeline provided in this embodiment can be achieved solely through structural optimization of the pipeline's inner wall, without the need for additional separation devices. The inclined flow-facing design also helps to control the increase in flow resistance while improving the oil and gas separation effect, ensuring the pipeline's ventilation efficiency.

[0007] In some embodiments, the connection position between the front surface and the bottom surface includes at least one front end point facing the air inlet end, and the tangent through the front end point is set at a first angle with the axial direction of the pipeline body, and the opening of the first angle faces the air outlet end; the first angle is θ, and θ satisfies: 25°≤θ≤35°.

[0008] The first included angle θ satisfies the range constraint of 25°≤θ≤35°, which helps to avoid insufficient airflow deflection due to the small angle between the frontal surface and the airflow direction, making it difficult to form a longitudinal vortex with sufficient intensity and weakening the transport effect of oil and gas particles to the pipe wall; it also helps to alleviate the problem of airflow directly impacting the fin-shaped protrusions caused by the excessive angle between the frontal surface and the airflow direction, and prevents the pipeline flow resistance from increasing significantly.

[0009] In some embodiments, the fin-shaped protrusion further includes a backflow surface facing the air outlet, the backflow surface being inclined along the direction from the air inlet to the air outlet.

[0010] When exhaust gas carrying oil and gas particles flows from the inlet to the outlet, the airflow can be gradually deflected and lifted along the inclined frontal surface, reducing the direct impact between the airflow and the fin-shaped protrusions and helping to control the increase in pipeline flow resistance. After passing the top of the fin-shaped protrusions, the airflow can smoothly transition along the inclined back-flow surface, optimizing the flow field state in the wake region behind the fin-shaped protrusions. This makes it easier to form a structurally stable and appropriately strong longitudinal vortex in the region behind the fin-shaped protrusions near the outlet. This longitudinal vortex can actively entrain oil and gas particles in the central region of the pipeline towards the pipe wall region. Combined with the relatively small flow field velocity at the pipe wall, it can promote the deposition of more oil and gas particles on the pipe wall behind the protrusions, thereby improving the removal efficiency of oil and gas particles in the exhaust gas and improving the exhaust gas purification performance.

[0011] In some embodiments, the radial dimension of the fin-shaped protrusion along the pipeline body is H, where H satisfies: 0.055D ≤ H ≤ 0.075D; where D is the inner diameter of the pipeline body. This size range ensures that the longitudinal vortex formed behind the fin-shaped protrusion has a sufficient influence range to effectively cover the central area of ​​the pipeline, actively drawing oil and gas particles at the center towards the lower flow velocity area of ​​the pipe wall, improving particle deposition and reducing the amount of particles escaping with the airflow; at the same time, it can also control the pipeline pressure loss at a reasonable level, avoiding a significant increase in flow resistance due to excessively high fin-shaped protrusion height, thus achieving a good balance between improving oil and gas separation effect and controlling ventilation energy consumption.

[0012] In some embodiments, H satisfies: 0.8 mm ≤ H ≤ 2.1 mm. When the height of the fin protrusion is below the lower limit of 0.8 mm, although a small pipeline pressure loss can be maintained, the scale of the vortex generated behind the fin protrusion is limited, making it difficult to effectively cover the central area of ​​the pipeline. This easily leads to more oil and gas particles flowing out of the pipeline with the gas flow, resulting in insufficient particle deposition. When the height of the fin protrusion is above the upper limit of 2.1 mm, although the intensity and range of the longitudinal vortex behind the fin protrusion can be increased, drawing more oil and gas particles towards the pipe wall to promote particle deposition, it also causes a significant increase in pipeline pressure loss.

[0013] In some embodiments, the fin-shaped protrusions further include a first connecting surface and a second connecting surface arranged circumferentially along the pipeline body, both the first and second connecting surfaces being connected between the bottom and top surfaces; the flow-facing surface is connected between the first and second connecting surfaces; the maximum distance between the first and second connecting surfaces is W, where W satisfies: 0.9H ≤ W ≤ 1.5H. Controlling W between 0.9H and 1.5H allows for a reasonable match between the circumferential width and radial height of the fin-shaped protrusions. Combined with the guiding effect of the flow-facing surface, the airflow passing through the fin-shaped protrusions can form a longitudinal vortex with a suitable circumferential coverage and a stable, concentrated structure, effectively drawing oil and gas particles from the central region of the pipeline towards the lower-velocity pipe wall, thus improving the deposition effect of the oil and gas particles. Simultaneously, at this ratio, the fin-shaped protrusions provide moderate obstruction to the airflow, keeping the pipeline pressure loss at a reasonable level, achieving a good balance between improving oil and gas separation efficiency and controlling ventilation resistance.

[0014] In some embodiments, W satisfies: 0.09 mm ≤ W ≤ 3.15 mm. Controlling W within the range of 0.09 mm to 3.15 mm allows the circumferential width of the fin-shaped protrusions to adapt to their own structure. Combined with the guiding effect of the frontal surface, the airflow passing through the fin-shaped protrusions can generate a longitudinal vortex with appropriate circumferential coverage and a concentrated and stable structure. This vortex can continuously entrain and transport oil and gas particles in the central region of the pipeline to the pipe wall region with lower flow velocity, increasing the amount of particles deposited on the pipe wall behind the fin-shaped protrusions and improving the oil and gas separation effect. At the same time, at this size, the impact of the fin-shaped protrusions on the flow cross section is within a reasonable range, and the increase in ventilation pressure loss is controllable, achieving a better balance between oil and gas separation efficiency and flow energy consumption.

[0015] In some embodiments, the top surface is an arc-shaped surface with a radius of R, where R satisfies: 0.4H ≤ R ≤ 0.8H. Controlling R within the range of 0.4H-0.8H allows for a good match between the arc curvature of the top surface and the radial height of the fin-shaped protrusions. This enables a smooth transition of airflow from the front surface to the back surface via the arc-shaped top surface, reducing local flow separation and turbulence losses, and helping to control the increase in pipeline pressure loss. Simultaneously, the appropriate curvature guides the airflow to form a stable lifting momentum component, generating a longitudinal vortex with concentrated vortex nuclei and a regular structure behind the fin-shaped protrusions. This continuously draws oil and gas particles from the center of the pipeline towards the lower-velocity pipe wall region, promoting particle deposition on the pipe wall behind the fin-shaped protrusions, achieving a better balance between improving oil and gas separation and controlling ventilation pressure loss.

[0016] In some embodiments, the dimension of the fin-shaped protrusion along the axial direction of the pipeline body is L, where L satisfies: 0.11D≤L≤0.15D; where D is the inner diameter of the pipeline body. Controlling L within the range of 0.11D-0.15D allows for a matching flow-facing length to the pipe diameter at a fixed lifting angle. This enables the airflow to smoothly complete its deflection and lifting along the flow-facing surface, mitigating abrupt flow changes and increased local resistance caused by excessively short strokes. Simultaneously, it ensures sufficient lifting momentum to form a moderately strong and structurally stable longitudinal vortex behind the fin-shaped protrusion. This vortex continuously draws oil and gas particles from the center of the pipeline towards the lower-velocity pipe wall region, promoting particle deposition on the pipe wall behind the fin-shaped protrusion and improving oil-gas separation efficiency. Furthermore, this ratio ensures that the axial proportion of the fin-shaped protrusion and the wall friction are at a reasonable level, keeping the overall pipeline pressure loss within an appropriate range. This achieves a balanced optimization effect between oil-gas separation efficiency and ventilation energy consumption, perfectly matching the pipe diameter.

[0017] In some embodiments, the dimension of the fin-shaped protrusion along the axial direction of the pipeline body is L, where L satisfies: 1.6 mm ≤ L ≤ 4.2 mm. Controlling L within the range of 1.6 mm to 4.2 mm allows for a suitable length of the frontal surface to be matched with a fixed lifting angle and a first included angle. This enables the airflow to smoothly complete its deflection and lifting along the frontal surface, mitigating the abrupt changes in flow pattern and the surge in local resistance caused by excessively short strokes. Simultaneously, it ensures that the airflow accumulates sufficient lifting momentum to generate a moderately strong and structurally stable longitudinal vortex behind the fin-shaped protrusion. This vortex continuously draws oil and gas particles from the center of the pipeline towards the lower-velocity pipe wall for deposition, improving the oil-gas separation effect. Furthermore, at this size, the guiding length of the frontal surface and the wall friction are in a reasonable balance, allowing the overall pressure loss of the pipeline to be controlled at an appropriate level, achieving a better balance between oil-gas separation efficiency and ventilation energy consumption.

[0018] In some embodiments, the inner wall of the pipeline body is provided with multiple sets of fin-shaped protrusions, which are spaced apart along the axial direction of the pipeline body. Each set of fin-shaped protrusions includes multiple fin-shaped protrusions arranged circumferentially along the pipeline body. In any two adjacent sets of fin-shaped protrusions, the fin-shaped protrusions in the first set and the fin-shaped protrusions in the second set are arranged alternately along the circumferential direction of the pipeline body. The arrangement of multiple sets of fin-shaped protrusions on the inner wall of the pipeline body, combined with axial spacing, single-set circumferential spacing, and alternating circumferential layout of adjacent sets, can balance the initial oil-gas separation efficiency with the long-term pipeline flow stability.

[0019] In some embodiments, the distance between two adjacent sets of fin-shaped protrusions is P, where P satisfies: P = 1.5D; where D is the inner diameter of the pipeline body. Setting the axial distance P between two adjacent sets of fin-shaped protrusions to 1.5 times the inner diameter D of the pipeline body can match the effective length of the longitudinal vortex and take into account both oil-gas separation efficiency and long-term pipeline flow stability.

[0020] In some embodiments, each group of fin-shaped protrusions includes N fin-shaped protrusions arranged at equal intervals along the circumference of the pipeline body; where N satisfies: N≥4, and N is an integer. Each group of fin-shaped protrusions consists of N fin-shaped protrusions arranged at equal intervals along the circumference of the pipeline body, and N is an integer not less than 4. This lower limit of the number takes into account both the circumferential coverage efficiency of the early oil and gas separation and the pipeline flow stability during long-term operation.

[0021] Secondly, this application also provides an exhaust gas recirculation device, which includes a cooler and an exhaust gas inlet pipe as described in any one of the first aspect embodiments, the exhaust gas inlet pipe being connected to the cooler. A large amount of oil and gas particles in the exhaust gas output from the exhaust gas inlet pipe are deposited on the inner wall of the exhaust gas inlet pipe, reducing the amount of sludge entering the cooler and downstream components such as the exhaust gas recirculation valve and throttle valve; the pressure loss of the exhaust gas inlet pipe is small, having minimal impact on the exhaust gas recirculation rate; the long-term high reliability of the exhaust gas inlet pipe can significantly improve the service life and intake cleanliness of the exhaust gas recirculation device's intake passage control valve.

[0022] Thirdly, embodiments of this application also provide an engine, which includes an exhaust pipe and an exhaust gas recirculation device as described in the second aspect embodiment. The exhaust gas intake pipe of the exhaust gas recirculation device is connected to the exhaust pipe. The exhaust gas output from the engine exhaust pipe is recirculated through the exhaust gas recirculation device. In the exhaust gas recirculation device, the exhaust gas intake pipe, which is directly connected to the exhaust pipe, actively enhances particulate deposition in the early stage to protect the downstream valve body. Even after being covered by sludge in the later stage, it does not significantly increase the system resistance, thus achieving a balance between long-term reliable operation and low maintenance costs. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of an exhaust gas inlet pipe provided in an embodiment of this application; Figure 2 for Figure 1 Sectional view of AA; Figure 3 and Figure 4 All Figure 2 Enlarged view at point B in the middle; Figure 5 A schematic diagram of the axial structure of an exhaust gas inlet pipe provided in an embodiment of this application; Figure 6 for Figure 5 Enlarged view at point C; Figure 7 This is a surface plot of gas velocity isotopes. Figure 8 This is a schematic diagram illustrating the simulation effect of eddy current deposition. Figure 9 This is a schematic diagram of the structure of a waste gas recirculation device provided in an embodiment of this application; Figure 10 This application provides a schematic diagram of the structure of an engine according to an embodiment of the present application; Icons: 100 - Exhaust gas intake pipe; 200 - Cooler; 300 - Exhaust pipe; 110 - Pipe body; 120 - Fin-shaped protrusion; 111 - Inlet end; 112 - Outlet end; 121 - Bottom surface; 122 - Top surface; 123 - Frontal surface; 124 - Backal surface; 125 - First connecting surface; 126 - Second connecting surface. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone.

[0025] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0026] like Figures 1 to 4As shown in the figure, this application embodiment provides an exhaust gas inlet pipe 100, which includes a pipe body 110 and a fin-shaped protrusion 120 disposed on the inner wall of the pipe body 110. The pipe body 110 includes an inlet end 111 and an outlet end 112 that are opposite to each other. The fin-shaped protrusion 120 includes a bottom surface 121, a top surface 122 and a flow-facing surface 123 connecting the bottom surface 121 and the top surface 122. The flow-facing surface 123 is located on the side of the fin-shaped protrusion 120 facing the inlet end 111, and the flow-facing surface 123 is inclined along the direction from the inlet end 111 to the outlet end 112.

[0027] The exhaust gas inlet pipe 100 provided in this embodiment of the application improves the deposition and separation effect of oil and gas particles in the exhaust gas by setting a fin-shaped protrusion 120 structure on the inner wall of the pipe body 110 through flow field regulation. The fin-shaped protrusion 120 is connected to the inner wall of the pipe body 110 with its bottom surface 121. The side of the fin-shaped protrusion 120 facing the inlet end 111 has a flow-facing surface 123 connecting the bottom surface 121 and the top surface 122. The flow-facing surface 123 is inclined along the direction from the inlet end 111 to the outlet end 112, forming a flow-guiding structure in the direction of airflow. When the exhaust gas carrying oil and gas particles moves from the inlet end 111 to the outlet end 112, it moves along the direction of airflow. Figure 2 When the airflow flows in the Q direction, it can be gradually deflected and lifted along the inclined frontal surface 123, reducing the direct impact between the airflow and the fin-shaped protrusions 120. This helps control the increase in pipeline flow resistance. Simultaneously, the airflow smoothly guided by the frontal surface 123, after passing the fin-shaped protrusions 120, is more likely to form a longitudinal vortex in the area behind the fin-shaped protrusions 120 near the outlet end 112. This longitudinal vortex can actively entrain oil and gas particles in the central region of the pipeline towards the pipe wall. Combined with the relatively small flow velocity at the pipe wall, this promotes the deposition of more oil and gas particles on the pipe wall behind the fin-shaped protrusions 120, thereby improving the removal efficiency of oil and gas particles in the exhaust gas and enhancing exhaust gas purification performance. The exhaust gas inlet pipeline 100 provided in this embodiment can be achieved simply through structural optimization of the pipeline inner wall, without the need for additional separation devices. The design of the inclined frontal surface 123 also helps to control the increase in flow resistance while improving the oil and gas separation effect, ensuring the pipeline's ventilation efficiency.

[0028] In some embodiments, the frontal surface 123 is a smooth surface.

[0029] In some embodiments, the fin-shaped protrusion 120 and the pipeline body 110 are integrally formed. The fin-shaped protrusion 120 and the pipeline body 110 form a stable and integrated whole. The fin-shaped protrusion will not shift during use, and no additional scale build-up points will be formed at the joints or steps during the sludge deposition process. It can continuously and stably generate the expected longitudinal vortex, ensuring that the fin-shaped protrusion 120 has a stable and controllable entrainment effect on oil and gas particles in the center of the pipeline, and maintaining the consistency of oil and gas separation efficiency.

[0030] The fin-shaped protrusion 120 and the pipe body 110 of the above-mentioned integrated structure can be implemented in various ways. For example, the fin-shaped protrusion 120 and the pipe body 110 are integrally formed. Alternatively, the fin-shaped protrusion 120 and the pipe body 110 can be welded. Alternatively, the fin-shaped protrusion 120 and the pipe body 110 can be bonded.

[0031] In some embodiments, such as Figure 3 and Figure 4 As shown, and in combination Figure 2 The connection point between the air-facing surface 123 and the bottom surface 121 includes at least one front end point facing the air intake end 111. The cross-section of the front end point forms a first angle with the axial direction of the pipe body 110, and the opening of the first angle faces the air outlet end 112. The first angle is θ, which satisfies: 25°≤θ≤35°. For example, the first angle θ can be any value between 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, or 25°-35°. In some implementations, the first angle is 30°.

[0032] It is understandable that the connection between the front surface 123 and the bottom surface 121 is a connecting line segment, and the aforementioned front end point can be understood as the point on this connecting line segment closest to the air intake end 111.

[0033] The first included angle θ satisfies the constraint of 25°≤θ≤35°, which helps to avoid insufficient airflow deflection due to an excessively small angle between the frontal surface 123 and the airflow direction, making it difficult to form a sufficiently strong longitudinal vortex and weakening the transport effect of oil and gas particles to the pipe wall. It also helps to alleviate the problem of airflow directly impacting the fin-shaped protrusion 120 due to an excessively large angle between the frontal surface 123 and the airflow direction, preventing a significant increase in pipeline flow resistance. When the exhaust gas carrying oil and gas particles flows from the inlet end 111 to the outlet end 112, the airflow first contacts the front end of the fin-shaped protrusion 120 facing the inlet end 111. Within the 25°-35° angle range, the frontal surface 123 of the fin-shaped protrusion 120 is gently inclined along the airflow direction. Under the premise of controlling the increase in flow resistance, it can guide the near-wall airflow to deflect and lift along the surface of the fin-shaped protrusion 120, which helps to form a longitudinal vortex of suitable strength in the area behind the fin-shaped protrusion 120 near the outlet end 112. This longitudinal vortex can actively entrain oil and gas particles in the central region of the pipeline towards the pipe wall. Combined with the relatively lower flow velocity in the pipe wall region, it can promote the deposition of more oil and gas particles on the pipe wall behind the fin protrusion 120. The 25°-35° angle range can better balance oil and gas separation efficiency and ventilation resistance, which is conducive to ensuring the ventilation efficiency of the pipeline and controlling the increase of flow resistance.

[0034] In some embodiments, the fin protrusion 120 includes a backflow surface 124 facing the air outlet 112, the backflow surface 124 being inclined along the direction from the air inlet 111 to the air outlet 112.

[0035] The fin-shaped protrusion 120 also includes a backflow surface 124 connecting the bottom surface 121 and the top surface 122. The backflow surface 124 is located on the side of the fin-shaped protrusion 120 facing the outlet end 112. The backflow surface 124 is also inclined along the direction from the inlet end 111 to the outlet end 112, which matches the inclined shape of the frontflow surface 123, so that the fin-shaped protrusion 120 as a whole has a configuration that extends in the direction of airflow. When exhaust gas carrying oil and gas particles flows from the inlet 111 to the outlet 112, the airflow can be gradually deflected and lifted along the inclined frontal surface 123, reducing the direct impact between the airflow and the fin-shaped protrusions 120 and helping to control the increase in pipeline flow resistance. After the airflow passes the top of the fin-shaped protrusions 120, it can smoothly transition along the inclined back surface 124, optimizing the flow field state in the wake region behind the fin-shaped protrusions 120, and making it easier to form a structurally stable and appropriately strong longitudinal vortex in the region behind the fin-shaped protrusions 120 near the outlet 112. This longitudinal vortex can actively entrain oil and gas particles in the central region of the pipeline towards the pipe wall region. Combined with the relatively small flow field velocity at the pipe wall, it can promote the deposition of more oil and gas particles on the pipe wall behind the fin-shaped protrusions 120, thereby improving the removal efficiency of oil and gas particles in the exhaust gas and improving the exhaust gas purification performance.

[0036] In some embodiments, such as Figure 2 and Figure 4 As shown, the fin-shaped protrusion 120 has a radial dimension of H along the pipe body 110, where H satisfies: 0.055D ≤ H ≤ 0.075D; where D is the inner diameter of the pipe body 110. For example, H can be any value between 0.055D, 0.056D, 0.057D, 0.058D, 0.059D, 0.06D, 0.061D, 0.062D, 0.063D, 0.064D, 0.065D, 0.066D, 0.067D, 0.068D, 0.069D, 0.07D, 0.071D, 0.072D, 0.073D, 0.074D, 0.075D, or 0.055D-0.075D. The dimension H of the fin-shaped protrusion 120 along the radial direction of the pipe body 110 can be understood as the height H of the fin-shaped protrusion 120.

[0037] In this embodiment, the height H of the fin-shaped protrusion 120 is limited to the range of 0.055D-0.075D, which is a range of values ​​that comprehensively considers the deposition effect of oil and gas particles on the pipe wall and the pressure loss of the pipeline. If the height of the fin-shaped protrusion 120 is too high, although it can increase the intensity and range of the longitudinal vortex behind the fin-shaped protrusion 120 and roll a larger area of ​​oil and gas particles toward the pipe wall to promote particle deposition, it will also cause a significant increase in pipeline pressure loss. If the height of the fin-shaped protrusion 120 is too low, although it can maintain a smaller pipeline pressure loss, the range of the vortex generated behind the fin-shaped protrusion 120 is limited and it is difficult to cover the central area of ​​the pipeline, which can easily lead to a large number of oil and gas particles flowing out of the pipeline with the gas flow. This size range ensures that the longitudinal vortex formed behind the fin protrusion 120 has a sufficient range of influence to effectively cover the central area of ​​the pipeline, actively drawing oil and gas particles in the center towards the lower flow velocity area of ​​the pipe wall, improving particle deposition and reducing the amount of particles escaping with the airflow; at the same time, it can control the pipeline pressure loss at a reasonable level, avoiding a significant increase in flow resistance due to excessive height of the fin protrusion 120, thus achieving a good balance between improving the oil and gas separation effect and controlling ventilation energy consumption.

[0038] In some embodiments, H satisfies: 0.8 mm ≤ H ≤ 2.1 mm. For example, H can be any value between 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, or 0.8 mm - 2.1 mm.

[0039] When the height of the fin protrusion 120 is below the lower limit of 0.8 mm, although a small pipeline pressure loss can be maintained, the scale of the vortex generated behind the fin protrusion 120 is limited, making it difficult to effectively cover the central area of ​​the pipeline. This easily leads to more oil and gas particles flowing out of the pipeline with the gas flow, resulting in insufficient particle deposition. When the height of the fin protrusion 120 is above the upper limit of 2.1 mm, although the intensity and range of the longitudinal vortex behind the fin protrusion 120 can be increased, drawing more oil and gas particles towards the pipe wall to promote particle deposition, it also causes a significant increase in pipeline pressure loss.

[0040] In some embodiments, such as Figure 5 and Figure 6As shown, the fin-shaped protrusion 120 also includes a first connecting surface 125 and a second connecting surface 126 arranged circumferentially along the pipe body 110. Both the first connecting surface 125 and the second connecting surface 126 are connected between the bottom surface 121 and the top surface 122. The flow-facing surface 123 is connected between the first connecting surface 125 and the second connecting surface 126. The maximum distance between the first connecting surface 125 and the second connecting surface 126 is W, where W satisfies: 0.9H ≤ W ≤ 1.5H. For example, W can be any value between 0.9H, 1H, 1.1H, 1.2H, 1.3H, 1.4H, 1.5H, or 0.9H-1.5H. The maximum distance W between the first connecting line and the second connecting line can be understood as the width of the fin-shaped protrusion 120.

[0041] When W is below the lower limit of 0.9H, the circumferential width of the fin-shaped protrusion 120 is relatively narrow compared to its radial height. The circumferential extension of the first connecting surface 125 and the second connecting surface 126 is insufficient. The circumferential range of the longitudinal vortex formed after the airflow passes through the fin-shaped protrusion 120 is limited, and the entrainment and coverage of oil and gas particles in the central area of ​​the pipeline is not sufficient. This is not conducive to fully utilizing the particle transport function of the vortex, and the improvement in the oil and gas particle deposition effect is limited, only maintaining a relatively low pipeline pressure loss. When W is above the upper limit of 1.5H, the circumferential width of the fin-shaped protrusion 120 is relatively wide compared to its radial height. The distance between the first connecting surface 125 and the second connecting surface 126 is too large, which will increase the obstruction area of ​​the fin-shaped protrusion 120 on the airflow in the pipeline, easily leading to a significant increase in pipeline pressure loss. At the same time, the excessively wide circumferential dimension will easily cause the vortex shape behind the fin-shaped protrusion 120 to be dispersed, making it difficult to form a concentrated and stable longitudinal vortex. Instead, it will weaken the effect of the vortex in entraining oil and gas particles towards the pipe wall.

[0042] By controlling W between 0.9H and 1.5H, the circumferential width and radial height of the fin-shaped protrusions 120 are reasonably matched. Combined with the guiding effect of the flow-facing surface 123, the airflow passing through the fin-shaped protrusions 120 forms a longitudinal vortex with suitable circumferential coverage and a stable, concentrated structure. This effectively draws oil and gas particles from the central region of the pipeline towards the lower-velocity pipe wall, improving the deposition effect. Simultaneously, at this ratio, the fin-shaped protrusions 120 provide a moderate degree of airflow obstruction, keeping pipeline pressure loss at a reasonable level.

[0043] In some embodiments, W satisfies: 0.09 mm ≤ W ≤ 3.15 mm. For example, W can be any value between 0.09 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3 mm, 3.1 mm, 3.15 mm, or 0.09 mm - 3.15 mm.

[0044] When W is below the lower limit of 0.09 mm, the circumferential width of the fin-shaped protrusion 120 is too small. The circumferential disturbance range generated by the airflow passing through the fin-shaped protrusion 120 is limited. The subsequent longitudinal vortex is difficult to reach the mainstream particle region in the center of the pipeline. Most of the oil and gas particles in the central region will flow directly out of the pipeline with the mainstream. The effect of improving the particle deposition at the pipe wall is limited, and it can only maintain a low flow resistance. When W is above the upper limit of 3.15 mm, the degree of crowding of the pipeline flow section by the fin-shaped protrusion 120 increases significantly, which will significantly increase the overall ventilation pressure loss of the pipeline. At the same time, the excessively wide circumferential width makes it easy for the airflow to differentiate into multiple dispersed small-scale vortices on both sides of the fin-shaped protrusion 120. They cannot converge into a structurally complete and uniformly strong longitudinal vortex. Instead, it will weaken the role of the vortex in transporting oil and gas particles to the pipe wall, and the benefit of improving oil and gas deposition efficiency will be greatly reduced.

[0045] In some embodiments, the fin-shaped protrusion 120 has a dimension L along the axial direction of the pipe body 110, where L satisfies: 0.11D ≤ L ≤ 0.15D; and D is the inner diameter of the pipe body 110. For example, L can be any value between 0.11D, 0.12D, 0.13D, 0.14D, 0.15D, or 0.11D-0.15D.

[0046] Understandably, under the same lifting angle, i.e. the aforementioned first included angle θ, the size of L directly corresponds to the extension length of the frontal surface 123: the smaller L is, the shorter the frontal surface 123 is, and the larger L is, the longer the frontal surface 123 is.

[0047] When L is below the lower limit of 0.11D, the length of the corresponding upstream surface 123 is relatively short compared to the pipe diameter. The airflow needs to complete the deflection and lifting at a predetermined angle within a very short axial stroke, resulting in a large flow turning gradient. This easily leads to local separation and turbulent disturbances at the end of the upstream surface 123. This will increase the local flow resistance of the pipeline and cause the flow pattern to become turbulent after the airflow leaves the fin-shaped protrusion 120, making it difficult to form a well-structured longitudinal vortex. The vortex's entrainment effect on oil and gas particles in the central region of the pipeline is insufficient, limiting the improvement of the deposition effect of oil and gas particles on the pipe wall.

[0048] When L exceeds the upper limit of 0.15D, the length of the corresponding frontal surface 123 is too long relative to the pipe diameter. The deflection process of the airflow along the inclined surface is too gentle, resulting in insufficient lifting momentum. After flowing over the fin-shaped protrusions 120, it is unable to generate a sufficiently strong longitudinal vortex, weakening its ability to entrain and transport oil and gas particles in the center of the pipeline, making it difficult to achieve efficient deposition of oil and gas particles. At the same time, the excessive axial length increases the contact area between the airflow and the wall of the fin-shaped protrusions 120, increasing the frictional resistance along the pipeline. Furthermore, the excessively large axial proportion of the fin-shaped protrusions 120 also occupies more effective flow space, further increasing the overall pressure loss of the pipeline.

[0049] By controlling L within the ratio range of 0.11D-0.15D, the airflow can be smoothly deflected and lifted along the frontal surface 123, mitigating the abrupt changes in flow pattern and the surge in local resistance caused by an excessively short stroke. At the same time, it ensures that the airflow has a large lifting momentum, forming a moderately strong and structurally stable longitudinal vortex behind the fin protrusion 120. This vortex continuously rolls the oil and gas particles in the center of the pipeline towards the pipe wall region with lower flow velocity, promoting particle deposition on the pipe wall behind the fin protrusion 120 and improving the oil and gas separation effect. At the same time, under this ratio, the axial proportion of the fin protrusion 120 and the wall friction are at a reasonable level, which can control the overall pressure loss of the pipeline within an appropriate range.

[0050] In some embodiments, the fin-shaped protrusion 120 has a dimension L along the axial direction of the pipe body 110, where L satisfies: 1.6 mm ≤ L ≤ 4.2 mm. For example, L can be any value between 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3 mm, 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm, 3.5 mm, 3.6 mm, 3.7 mm, 3.8 mm, 3.9 mm, 4 mm, 4.1 mm, 4.2 mm, or 1.6 mm - 4.2 mm.

[0051] When L is below the lower limit of 1.6 mm, the length of the corresponding frontal surface 123 is too short. The airflow needs to complete the deflection and lifting at a predetermined angle within a very short stroke. The turning gradient is too large, which easily causes local flow separation and turbulence at the tail of the frontal surface 123. This will not only increase the local flow resistance, but also cause the flow to become turbulent after the airflow leaves the fin protrusion 120, making it difficult to form a well-structured longitudinal vortex.

[0052] When L exceeds the upper limit of 4.2 mm, the length of the corresponding frontal surface 123 is too long, and the deflection process of the airflow along the inclined surface is too gentle. Although the fit between the airflow and the wall is improved and the local impact resistance is reduced, the longitudinal vortex with sufficient intensity cannot be generated after flowing through the fin protrusion 120, and the ability to entrain and transport oil and gas particles in the central area of ​​the pipeline is weak. At the same time, the excessive axial extension will increase the contact area between the airflow and the surface of the fin protrusion 120, and the frictional resistance along the way will increase accordingly, resulting in an increase in overall pressure loss.

[0053] In some embodiments, the top surface 122 is an arc-shaped surface with a radius of R, where R satisfies: 0.4H ≤ R ≤ 0.8H. For example, R can be any value between 0.4H, 0.5H, 0.6H, 0.7H, 0.8H, or 0.4H-0.8H.

[0054] Understandably, the curved surface transitions smoothly to the frontal surface 123.

[0055] When R is below the lower limit of 0.4H, the curvature of the arc-shaped top surface 122 is too large and the top shape is too sharp. The turning gradient of the airflow when it transitions from the front surface 123 through the top surface 122 to the back surface 124 is large. It is easy for the airflow to detach from the wall in the junction area between the top surface 122 and the back surface 124, which will cause additional local turbulence. This will not only increase the local flow resistance of the pipeline, but also cause the longitudinal vortex shape behind the fin protrusion 120 to be disordered, weakening the longitudinal vortex's entrainment effect on the oil and gas particles in the center of the pipeline, which is not conducive to the continuous deposition of particles on the pipe wall.

[0056] When R is higher than the upper limit of 0.8H, the curvature of the arc-shaped top surface 122 is too small and the top shape is too gentle. The momentum of the airflow is insufficient during the flow along the top surface 122. After the airflow leaves the fin-shaped protrusion 120, it is difficult to form a longitudinal vortex with sufficient strength. The ability to entrain and transport oil and gas particles in the central area of ​​the pipeline is weak, and it is difficult to effectively promote the migration and deposition of particles towards the pipe wall. At the same time, the overly gentle top surface 122 will weaken the disturbance effect of the fin-shaped protrusion 120 on the airflow, and the effect of improving the deposition of oil and gas particles is limited.

[0057] By controlling R within the ratio range of 0.4H-0.8H, the arc curvature of the top surface 122 and the radial height of the fin protrusion 120 can be well matched. The airflow can smoothly transition from the front surface 123 to the back surface 124 through the arc top surface 122, reducing local flow separation and turbulence loss, and helping to control the increase in pipeline pressure loss. At the same time, the appropriate curvature can guide the airflow to form a stable lifting momentum component, generating a longitudinal vortex with concentrated vortex cores and a regular structure behind the fin protrusion 120. This continuously rolls the oil and gas particles in the center of the pipeline towards the pipe wall area with lower flow velocity, promoting particle deposition on the pipe wall behind the fin protrusion 120, and achieving a better balance between improving the oil and gas separation effect and controlling the ventilation pressure loss.

[0058] In some embodiments, R satisfies: 0.04 mm ≤ R ≤ 1.68 mm. For example, R can be any value between 0.04 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.62 mm, 1.64 mm, 1.68 mm, or 0.04 mm - 0.68 mm.

[0059] By controlling R within the range of 0.04 mm to 1.68 mm, the transition curvature of the top surface 122 can be adapted to the overall structure of the fin protrusion 120. After the airflow is lifted along the frontal surface 123, it can smoothly transition to the back-flow side via the arc-shaped top surface 122, reducing the local resistance loss caused by flow separation and keeping the increase in pipeline pressure loss at a reasonable level. At the same time, the appropriate curvature of the arc surface can supplement the airflow with a moderate lifting momentum, causing the airflow to form a structurally stable longitudinal vortex behind the fin protrusion 120, continuously entraining oil and gas particles in the central area of ​​the pipeline to the pipe wall area with lower flow velocity, promoting particle deposition on the pipe wall behind the fin protrusion 120, and achieving a good balance between improving the oil and gas separation effect and controlling ventilation energy consumption.

[0060] In some embodiments, such as Figure 2 As shown, the inner wall of the pipeline body 110 is provided with multiple sets of fin-shaped protrusions 120, which are spaced apart along the axial direction of the pipeline body 110. Each set of fin-shaped protrusions 120 includes multiple fin-shaped protrusions 120 arranged spaced apart along the circumference of the pipeline body 110. In any two adjacent sets of fin-shaped protrusions 120, along the circumference of the pipeline body 110, the fin-shaped protrusions 120 in the first set of fin-shaped protrusions 120 and the fin-shaped protrusions 120 in the second set of fin-shaped protrusions 120 are arranged alternately.

[0061] The inner wall of the pipeline body 110 adopts a design with multiple sets of fin-shaped protrusions 120. This design, combining axial spacing, circumferential spacing within a single set, and alternating circumferential arrangements between adjacent sets, balances initial oil-gas separation efficiency with long-term pipeline flow stability. In the initial stage of use, the multiple sets of fin-shaped protrusions 120 spaced axially allow the airflow to be gradually guided and disturbed during its travel, generating longitudinal vortices behind each set of fin-shaped protrusions 120. This continuously draws oil and gas particles from the center of the pipeline towards the pipe wall, gradually improving the deposition and separation effect. Multiple fin-shaped protrusions 120 spaced circumferentially within a single set can simultaneously create vortices at multiple locations along the pipeline's circumference, expanding the circumferential coverage of particle deposition. The alternating circumferential arrangement of adjacent sets of fin-shaped protrusions 120 supplements the circumferential areas not covered by the previous set, reducing circumferential deposition blind spots and further improving the overall oil-gas separation performance of the pipeline. As usage time increases, oil and gas particles gradually deposit to form sludge and cover the surface of the fin-shaped protrusions 120. Because the fin-shaped protrusions 120 are low in height and have a smooth surface, the inner wall of the pipeline can be restored to a state close to that of a smooth pipe after the sludge is covered. At the same time, the axially spaced and circumferentially alternating arrangement can guide the sludge to be distributed and deposited relatively evenly along the axial and circumferential directions of the pipeline, making it less likely for sludge to accumulate locally. This will not create new blockage points, nor will the flow resistance increase significantly due to the residue of the fin-shaped protrusions 120. This is beneficial to maintaining the stability of the ventilation pressure loss during long-term pipeline operation and reducing the risk of blockage.

[0062] In some embodiments, such as Figure 2 As shown, the distance between two adjacent sets of fin-shaped protrusions 120 is P, and P satisfies: P=1.5D; where D is the inner diameter of the pipe body 110.

[0063] Based on the initial oil-gas separation results, the longitudinal vortex generated by a single set of fin-shaped protrusions 120 has a corresponding effective range. Within this range, the vortex structure is stable and has sufficient ability to entrain particles. Beyond this range, the vortex gradually weakens and dissipates. Setting the inter-group spacing P to 1.5D allows the longitudinal vortex generated by the previous set of fin-shaped protrusions 120 to fully exert its transport function within the effective range, continuously entraining oil and gas particles in the corresponding pipe section towards the pipe wall for deposition. Simultaneously, at the point where the vortex intensity begins to significantly weaken, the next set of fin-shaped protrusions 120 is connected, and the next set of fin-shaped protrusions 120 regenerates a stable longitudinal vortex, creating a continuous guiding disturbance to the airflow. This achieves a step-by-step continuation of the oil-gas separation effect, avoiding the problems of mutual interference between adjacent flow fields and disordered vortex structures caused by excessively small spacing, as well as the problems of pipe section separation efficiency discontinuity and particles escaping with the airflow caused by excessively large spacing. This helps to improve the overall oil-gas separation efficiency of the pipeline.

[0064] From the perspective of long-term operational stability, the 1.5D axial spacing combined with the circumferential alternating arrangement can guide the deposited sludge to form a relatively uniform distribution on the inner wall of the pipeline, making it less likely to cause localized sludge accumulation due to overly dense arrangement of the fin protrusions 120. As the usage time increases, after the sludge gradually covers the fin protrusions 120, due to the low height and smooth surface of the fin protrusions 120, combined with the uniform deposition distribution, the inner wall of the pipeline can basically return to a state close to that of a smooth pipe. It will not form new blockage points due to unreasonable spacing between groups, nor will it cause a significant increase in ventilation pressure loss. This is conducive to maintaining the resistance stability of the pipeline during long-term operation and reducing the risk of blockage.

[0065] In some embodiments, such as Figure 5 As shown, each group of fin-shaped protrusions 120 includes N fin-shaped protrusions 120 arranged at equal intervals along the circumference of the pipe body 110; N satisfies: N≥4, and N is an integer. For example, N can be 4, 5, 6, 7, 8, 9, etc.

[0066] In the initial stage of oil-gas separation, an evenly spaced arrangement with N≥4 can create at least four uniformly distributed flow field disturbances around the pipeline circumference, corresponding to the generation of multiple sets of structurally stable longitudinal vortices. This effectively widens the circumferential entrainment range of oil and gas particles in the pipeline center by the vortices, reduces the circumferential deposition blind zone of a single set of fin protrusions 120, and improves the particle capture efficiency of the entire pipeline wall. If N is less than 4, the circumferential spacing between adjacent fin protrusions 120 is too large, and a single set of vortices cannot fully cover the blank area between adjacent fin protrusions 120. This results in a large number of oil and gas particles in the central area flowing out with the airflow without being entrained to the pipeline wall, significantly weakening the separation effect of a single set of fin protrusions 120. With the alternating circumferential layout of two adjacent sets of fin protrusions 120, the circumferential number with N≥4 allows the vortex coverage areas of the preceding and following sets to complement each other more fully, further eliminating circumferential deposition dead zones and progressively enhancing the overall oil-gas separation effect.

[0067] As operating time increases, sludge gradually deposits and covers the surface of the fin-shaped protrusions 120. The evenly spaced arrangement of N≥4 can guide the sludge to be evenly distributed in the circumference, making it less likely to cause localized sludge accumulation due to insufficient number of fin-shaped protrusions 120. Combined with the low height and smooth surface of the fin-shaped protrusions 120, the inner wall of the pipeline can basically return to a state close to a smooth pipe after the sludge is completely covered. No new blockage points will be formed, and the flow resistance will not increase significantly due to uneven circumferential deposition. It can maintain a stable ventilation pressure loss level of the pipeline in the long term and reduce the risk of blockage.

[0068] It is understandable that in two adjacent groups of fin-like protrusions 120, the rotation angle between two alternately arranged fin-like protrusions 120 is 180° / N. For example, if there are 4 fin-like protrusions 120 in each group, the rotation angle between two alternately arranged fin-like protrusions 120 is 180° / 4, or 45°.

[0069] The following is a detailed description of the exhaust gas inlet pipe 100 provided in an embodiment of this application, using an example: like Figures 2 to 6 As shown, the exhaust gas inlet pipe 100 includes a circular pipe body 110 and fin-shaped protrusions 120 disposed on the inner wall of the pipe body 110. The fin-shaped protrusions 120 include a bottom surface 121 connected to the inner wall and a top surface 122 facing the center of the pipe. The fin-shaped protrusions 120 also include a flow-facing surface 123 that smoothly transitions from the bottom surface 121 to the top surface 122, and the flow-facing surface 123 is inclined along the direction from the inlet end 111 to the outlet end 112 of the pipe body 110. The tangent at the front end point of the line segment connecting the flow-facing surface 123 and the bottom surface 121 forms a first angle with the axial direction of the pipe body 110, which can be understood as the lifting angle of the flow-facing surface 123. The height of a single fin-shaped protrusion 120 is between 0.8 mm and 2.1 mm, with the specific value selected based on pressure loss, thermal efficiency, and reliability. Each fin-shaped protrusion 120 is 4 mm long and 1.8 mm wide, with a smooth fin shape. The top surface 122 of the fin-shaped protrusion 120 has a large rounded corner, resulting in a smooth surface transition. The fin-shaped protrusions 120 are arranged on the inner wall of the pipe body 110 as follows: a group of fin-shaped protrusions 120 is provided every 45 mm, with each group consisting of four evenly distributed fin-shaped protrusions 120; in two adjacent groups of fin-shaped protrusions 120, the fin-shaped protrusions 120 in the first group and the fin-shaped protrusions 120 in the second group are arranged alternately with a rotation angle of 45°. The alternation of the fin-shaped protrusions 120 in the first group and the fin-shaped protrusions 120 in the second group with a rotation angle of 45° can be understood as the first fin-shaped protrusion 120 coinciding with the second group of fin-shaped protrusions after rotating 45°.

[0070] like Figure 7 and Figure 8As shown, the exhaust gas inlet pipe 100 provided in this embodiment can effectively enhance particle deposition. The fin-shaped protrusions 120, inclined along the airflow direction on the frontal surface 123, generate a moderate longitudinal vortex, actively drawing oil and gas particles in the central region of the pipe towards the relatively low-velocity pipe wall, promoting oil and gas deposition on the side of the fin-shaped protrusions 120 away from the airflow. The exhaust gas inlet pipe 100 provided in this embodiment can also achieve low flow resistance. The fin-shaped protrusions 120 are sparsely distributed with a height of 0.8 mm to 2.1 mm, and the increase in system pressure loss is controlled within 5%. The exhaust gas inlet pipe 100 provided in this embodiment also has excellent self-sacrificing characteristics: after initially exerting its adsorption and protective function, as sludge gradually covers the fin-shaped protrusions 120, due to the low height and smooth surface of the fin-shaped protrusions 120, the inner wall of the pipe essentially returns to a near-smooth pipe state, without forming new blockage points or significantly increasing resistance. The exhaust gas inlet pipe 100 provided in this application embodiment has high long-term reliability and effectively solves the problems of poor adsorption capacity of traditional smooth pipe walls and high resistance and easy blockage of ordinary raised structures.

[0071] This application also provides an exhaust gas recirculation device, such as... Figure 9 As shown, the exhaust gas recirculation device includes a cooler 200 and an exhaust gas inlet pipe 100 as described above, the exhaust gas inlet pipe 100 being connected to the cooler 200.

[0072] In the exhaust gas recirculation device provided in this application embodiment, a large amount of oil and gas particles in the exhaust gas output from the exhaust gas inlet pipe 100 are deposited on the inner wall of the exhaust gas inlet pipe 100, reducing the amount of sludge entering the cooler 200 and the exhaust gas recirculation valve, throttle valve, etc.; the pressure loss of the exhaust gas inlet pipe 100 is small, which has minimal impact on the exhaust gas recirculation rate; the long-term high reliability of the exhaust gas inlet pipe 100 can significantly improve the service life and intake cleanliness of the intake passage control valve of the exhaust gas recirculation device.

[0073] Thirdly, embodiments of this application also provide an engine, such as Figure 10 As shown, the engine includes an exhaust pipe 300 and an exhaust gas recirculation device as described in the second aspect embodiment, wherein the exhaust gas intake pipe 100 of the exhaust gas recirculation device is connected to the exhaust pipe 300.

[0074] The exhaust gas output from the engine exhaust pipe 300 is recirculated through the exhaust gas recirculation device. The exhaust gas intake pipe 100, which is directly connected to the exhaust pipe 300 in the exhaust gas recirculation device, actively enhances particulate deposition in the early stage to protect the downstream valve body. After being covered by sludge in the later stage, it does not significantly increase the system resistance, thus achieving a balance between long-term reliable operation and low maintenance costs.

[0075] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of this application. Therefore, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. An exhaust gas inlet pipe, characterized in that, Includes the pipe body and fin-shaped protrusions disposed on the inner wall of the pipe body; The exhaust gas inlet pipe includes an inlet end and an outlet end that are opposite to each other; the fin-shaped protrusion includes a bottom surface, a top surface, and a flow-facing surface connecting the bottom surface and the top surface; the flow-facing surface is located on the side of the fin-shaped protrusion facing the inlet end, and the flow-facing surface is inclined along the direction from the inlet end to the outlet end.

2. The exhaust gas inlet pipeline according to claim 1, characterized in that, The connection position between the front surface and the bottom surface includes at least one front end point facing the air inlet end. The tangent through the front end point is set at a first angle with the axial direction of the pipeline body, and the opening of the first angle faces the air outlet end. The first angle is θ, and θ satisfies: 25°≤θ≤35°.

3. The exhaust gas inlet pipeline according to claim 1, characterized in that, The fin-shaped protrusion also includes a backflow surface facing the air outlet, the backflow surface being inclined along the direction from the air inlet to the air outlet.

4. The exhaust gas inlet pipeline according to claim 1, characterized in that, The fin-shaped protrusion has a radial dimension H along the pipe body, where H satisfies: 0.055D≤H≤0.075D; where D is the inner diameter of the pipe body.

5. The exhaust gas inlet pipeline according to claim 4, characterized in that, The condition H satisfies: 0.8 mm ≤ H ≤ 2.1 mm.

6. The exhaust gas inlet pipeline according to claim 4, characterized in that, The fin-shaped protrusion further includes a first connecting surface and a second connecting surface arranged circumferentially along the pipeline body, both the first connecting surface and the second connecting surface being connected between the bottom surface and the top surface; the flow-facing surface is connected between the first connecting surface and the second connecting surface; the maximum distance between the first connecting surface and the second connecting surface is W, wherein W satisfies: 0.9H≤W≤1.5H.

7. The exhaust gas inlet pipeline according to claim 6, characterized in that, The W condition is: 0.09 mm ≤ W ≤ 3.15 mm.

8. The exhaust gas inlet pipeline according to claim 4, characterized in that, The top surface is an arc-shaped surface with a radius of R, where R satisfies: 0.4H ≤ R ≤ 0.8H.

9. The exhaust gas inlet pipeline according to claim 1, characterized in that, The fin-shaped protrusion has a dimension L along the axial direction of the pipe body, and L satisfies: 0.11D≤L≤0.15D; where D is the inner diameter of the pipe body.

10. The exhaust gas inlet pipeline according to claim 9, characterized in that, The fin-shaped protrusion has a dimension L along the axial direction of the pipeline body, and L satisfies: 1.6 mm ≤ L ≤ 4.2 mm.

11. The exhaust gas inlet pipe according to any one of claims 1-10, characterized in that, The inner wall of the pipeline body is provided with multiple sets of fin-shaped protrusions, which are spaced apart along the axial direction of the pipeline body. Each set of fin-shaped protrusions includes multiple fin-shaped protrusions arranged at intervals along the circumference of the pipeline body. In any two adjacent sets of fin-shaped protrusions, the fin-shaped protrusions in the first set and the fin-shaped protrusions in the second set are arranged alternately along the circumference of the pipeline body.

12. The exhaust gas inlet pipeline according to claim 11, characterized in that, The distance between two adjacent sets of fin-shaped protrusions is P, where P satisfies: P = 1.5D; where D is the inner diameter of the pipe body.

13. The exhaust gas inlet pipe according to claim 11, characterized in that, Each group of fin-shaped protrusions includes N fin-shaped protrusions arranged at equal intervals along the circumference of the pipeline body; N satisfies: N≥4, and N is an integer.

14. A waste gas recirculation device, characterized in that, The exhaust gas recirculation device includes a cooler and an exhaust gas inlet pipe as described in any one of claims 1-13, wherein the exhaust gas inlet pipe is connected to the cooler.

15. An engine, characterized in that, The engine includes an exhaust pipe and an exhaust gas recirculation device as described in claim 14, wherein the exhaust gas intake pipe of the exhaust gas recirculation device is connected to the exhaust pipe.

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