EGR system venturi tube design method, venturi tube, EGR system and vehicle

Abstract

The invention relates to an EGR system venturi tube design method, a venturi tube, an EGR system and a vehicle, and relates to the technical field of automobile part design, and the EGR system venturi tube design method comprises the steps that the midpoint slope of a contraction section of a contraction tube is preset based on the installation position of the contraction tube; based on the shrinkage section midpoint slope of the shrinkage pipe, the outlet straight pipe section radius of the shrinkage pipe, the shrinkage section change height of the shrinkage pipe and the distance from the shrinkage section midpoint of the shrinkage pipe to the end of the inlet straight pipe section, a curve of the cross section of the shrinkage pipe is obtained; and designing the shrinkage pipe based on the curve of the cross section of the shrinkage pipe. The curve of the section of the shrinkage pipe is obtained based on the shrinkage section midpoint slope of the shrinkage pipe, the outlet straight pipe section radius of the shrinkage pipe, the shrinkage section change height of the shrinkage pipe and the distance from the shrinkage section midpoint of the shrinkage pipe to the end part of the inlet straight pipe section, so that compared with the currently selected curve, the curve is better in continuity and smoother; the problem that the accuracy of EGR exhaust gas extraction and the system efficiency are affected due to the fact that changes of an inlet section and an outlet section of a curve selected at present are large is solved.

Description

Technical Field

[0001] This invention relates to the field of automotive component design technology, specifically to a venturi tube design method for an EGR system, a venturi tube, an EGR system, and a vehicle. Background Technology

[0002] In an EGR system, the venturi tube, as a core component, generates a pressure differential through its unique flow channel design, enabling efficient extraction of exhaust gas. Specifically, when the intake airflow passes through the throat of the venturi tube, the airflow velocity increases and the static pressure decreases. The pressure difference between the exhaust pipe and the throat allows for the extraction of EGR exhaust gas. The ratio of the intake pipe diameter to the throat diameter directly determines the amount of EGR exhaust gas extracted; therefore, the flow channel design of the venturi tube has a decisive impact on the performance of the EGR system.

[0003] A venturi tube typically consists of three parts: a contraction section, a throat, and a diffusing section. The contraction section gradually narrows the intake airflow from the larger diameter inlet to the throat, while the diffusing section gradually expands the airflow from the throat to the outlet. Properly designing the profiles of the contraction and diffusing sections of the venturi tube helps reduce flow separation, decrease engine intake losses, and improve the efficiency of the EGR system.

[0004] In existing technologies, the design of contraction and expansion pipes generally starts from first principles, determining the appropriate axial velocity components based on the fundamental equations of ideal flow, calculating the overall flow field distribution, and then selecting a streamline that meets the contraction ratio requirement as the contraction section. Commonly used contraction section curves include the Vitósinski curve, the Vitósinski axis-shifting curve, the double quadratic curve, the quadratic curve, and the quintic curve.

[0005] However, the inlet and outlet sections of the currently selected curves vary considerably, resulting in significant flow resistance and intake losses. Additionally, the airflow distribution at the throat is uneven, all of which affect the accuracy of EGR exhaust gas extraction and system efficiency. Summary of the Invention

[0006] This application provides a Venturi tube design method for an EGR system, a Venturi tube, an EGR system, and a vehicle. It can solve the problems in the prior art where the selected curve has large variations in the inlet and outlet sections, resulting in large flow resistance and intake losses. At the same time, the airflow distribution at the throat is uneven, all of which affect the accuracy of EGR exhaust gas extraction and system efficiency.

[0007] In a first aspect, embodiments of this application provide a venturi design method for an EGR system, comprising: Based on the installation position of the shrink tube, the slope of the midpoint of the shrink section of the shrink tube is preset; Based on the slope of the midpoint of the contraction section of the contraction tube, the radius of the outlet straight section of the contraction tube, the height variation of the contraction section of the contraction tube, and the distance from the midpoint of the contraction section of the contraction tube to the end of the inlet straight section, the curve of the cross-section of the contraction tube is obtained. The shrink tube is designed based on the curve of the shrink tube cross-section.

[0008] In one embodiment, designing the shrink tube based on the curve of the shrink tube cross-section includes: Based on the curve of the shrink tube cross-section, the cross-sectional shape of the shrink tube is obtained; The shrink tube is designed based on its cross-sectional shape.

[0009] In one embodiment, designing the shrink tube based on its cross-sectional shape includes: Select the port shape of the shrink tube; The shrink tube is designed based on the selected port shape and cross-sectional shape of the shrink tube.

[0010] In one embodiment, the end of the straight pipe section at the inlet of the contraction pipe is used as... The starting point for the design parameters of the direction is the centerline of the contraction tube. The starting point of the design parameters for the direction is based on the formula: Obtain the curve of the cross-section of the contraction tube; in, The radius of the straight pipe section at the outlet of the contraction pipe is given. The height variation of the contraction section of the contraction tube. The distance is the distance from the midpoint of the contraction section of the contraction tube to the end of the inlet straight pipe section. The slope at the midpoint of the contraction section of the contraction tube is given.

[0011] In one embodiment, the end of the straight pipe section at the inlet of the contraction pipe is used as... The starting point for the design parameters of the direction is the centerline of the contraction tube. The starting point of the design parameters for the direction is based on the formula: Obtain the curve of the cross-section of the contraction tube; in, The radius of the straight pipe section at the outlet of the contraction pipe is given. The height variation of the contraction section of the contraction tube. The slope at the midpoint of the contraction section of the contraction tube is given.

[0012] In one embodiment, the preset slope of the midpoint of the contraction section of the contraction tube based on its installation position includes: Based on the installation position of the shrink tube, the interference between the shrink tube and other components is obtained; Based on the interference between the shrink tube and other components, the slope of the midpoint of the shrink section of the shrink tube is preset.

[0013] In one embodiment, when the midpoint slope of the contraction section of the contraction tube is preset, the midpoint slope of the contraction section of the contraction tube is obtained based on an empirical table corresponding to the installation position of the contraction tube and the midpoint slope of the contraction section of the contraction tube.

[0014] Secondly, this application also provides a venturi tube, which is designed using the above-described venturi tube design method for an EGR system.

[0015] Thirdly, embodiments of this application also provide an EGR system, which includes the aforementioned Venturi tube.

[0016] Fourthly, embodiments of this application also provide a vehicle that includes the aforementioned EGR system.

[0017] The beneficial effects of the technical solutions provided in this application include: When designing the Venturi tube for an EGR system, the slope of the midpoint of the contraction section is preset based on the installation position of the contraction tube. The curve of the contraction tube cross-section is obtained based on this slope, the radius of the outlet straight pipe section, the height variation of the contraction section, and the distance from the midpoint of the contraction section to the end of the inlet straight pipe section. The contraction tube is then designed based on this curve. Because the curve of the contraction tube cross-section is obtained based on the midpoint slope of the contraction section, the radius of the outlet straight pipe section, the height variation of the contraction section, and the distance from the midpoint of the contraction section to the end of the inlet straight pipe section, it exhibits better continuity and smoother curves compared to currently used curves. This solves the problems of large variations in the inlet and outlet sections of currently used curves, resulting in significant flow resistance and intake losses, as well as uneven airflow distribution at the throat, all of which affect the accuracy of EGR exhaust gas extraction and system efficiency. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating an embodiment of the Venturi tube design method for an EGR system according to the present invention.

[0020] Figure 2 This is a schematic diagram of an embodiment of the Venturi tube design method for an EGR system according to the present invention.

[0021] Figure 3 This is a schematic diagram of the curve variation of an embodiment of the Venturi tube design method for an EGR system according to the present invention.

[0022] Figure 4 This is a schematic diagram of the external appearance of a first embodiment of a venturi tube according to the present invention.

[0023] Figure 5 This is a schematic diagram of the external appearance of a second embodiment of a venturi tube according to the present invention. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0025] This application provides a Venturi tube design method for an EGR system, a Venturi tube, an EGR system, and a vehicle. It can solve the problems in the prior art where the selected curve has large variations in the inlet and outlet sections, resulting in large flow resistance and intake losses. At the same time, the airflow distribution at the throat is uneven, all of which affect the accuracy of EGR exhaust gas extraction and system efficiency.

[0026] like Figure 1 As shown, this application provides a venturi tube design method for an EGR system, which includes: Based on the installation position of the shrink tube, the slope of the midpoint of the shrink section of the shrink tube is preset; The curve of the shrinkage tube cross section is obtained based on the slope of the midpoint of the shrinkage section, the radius of the outlet straight section of the shrinkage tube, the height variation of the shrinkage section of the shrinkage tube, and the distance from the midpoint of the shrinkage section of the shrinkage tube to the end of the inlet straight section. Design the shrink tube based on the curve of the shrink tube cross-section.

[0027] When designing the Venturi tube for an EGR system, the slope of the midpoint of the contraction section is preset based on the installation position of the contraction tube. The curve of the contraction tube cross-section is obtained based on this slope, the radius of the outlet straight pipe section, the height variation of the contraction section, and the distance from the midpoint of the contraction section to the end of the inlet straight pipe section. The contraction tube is then designed based on this curve. Because the curve of the contraction tube cross-section is obtained based on the midpoint slope of the contraction section, the radius of the outlet straight pipe section, the height variation of the contraction section, and the distance from the midpoint of the contraction section to the end of the inlet straight pipe section, it exhibits better continuity and smoother curves compared to currently used curves. This solves the problems of large variations in the inlet and outlet sections of currently used curves, resulting in significant flow resistance and intake losses, as well as uneven airflow distribution at the throat, all of which affect the accuracy of EGR exhaust gas extraction and system efficiency.

[0028] In some optional embodiments, the design of the shrink tube based on the curve of the shrink tube cross-section includes: Based on the curve of the shrink tube cross-section, obtain the cross-sectional shape of the shrink tube; Design the shrink tube based on its cross-sectional shape.

[0029] In this embodiment, the design of the contraction tube based on the curve of its cross-section specifically includes: obtaining the cross-sectional shape of the contraction tube based on the curve of its cross-section, and designing the contraction tube based on its cross-sectional shape. The cross-sectional shape of the contraction tube can be obtained by symmetrically passing the curve of the contraction tube's cross-section through the axis of the contraction tube. Designing the contraction tube based on its cross-sectional shape is more efficient and helps to solve the problems in the existing technology where the selected curve has large variations in the inlet and outlet sections, resulting in large flow resistance and intake losses. At the same time, the airflow distribution at the throat is uneven, all of which affect the accuracy of EGR exhaust gas extraction and system efficiency.

[0030] In some optional embodiments, designing the shrink tube based on its cross-sectional shape includes: Select the port shape of the shrink tube; Design the shrink tube based on the selected port shape and cross-sectional shape of the shrink tube.

[0031] In this embodiment, the shrink tube is designed based on its cross-sectional shape, specifically including: selecting the port shape of the shrink tube, and designing the shrink tube based on the selected port shape and the cross-sectional shape of the shrink tube. This step ensures that the port shape of the shrink tube is precisely matched with the spatial layout and fluid dynamics requirements of the actual installation environment. By co-optimizing the port shape and the cross-sectional shape of the shrink section, a smooth and continuous flow channel transition structure is formed, which significantly reduces the turbulent loss of airflow in the inlet and outlet regions, and makes the airflow velocity distribution at the throat more uniform and stable. This solves the problems in the prior art where the selected curve has large variations in the inlet and outlet sections, resulting in large flow resistance and intake losses, and the airflow distribution at the throat is uneven, all of which affect the accuracy of EGR exhaust gas extraction and system efficiency.

[0032] like Figure 2 and Figure 3 As shown, in some optional embodiments, the end of the straight pipe section at the inlet of the contraction pipe is used as... The starting point for the directional design parameters is the centerline of the contraction tube. The starting point of the design parameters for the direction is based on the formula: Obtain the curve of the shrink tube cross-section; in, The radius of the straight pipe section at the outlet of the contraction pipe. The height of the contraction section of the contraction tube varies. This is the distance from the midpoint of the contraction section of the contraction pipe to the end of the inlet straight pipe section. The slope is the midpoint of the contraction section of the contraction tube.

[0033] In this embodiment, the end of the straight pipe section at the inlet of the contraction pipe is used as... The starting point for the directional design parameters is the centerline of the contraction tube. The starting point of the design parameters for the direction is based on the formula: Obtain the curve of the shrinkage tube cross-section; where, The radius of the straight pipe section at the outlet of the contraction pipe. The height of the contraction section of the contraction tube varies. This is the distance from the midpoint of the contraction section of the contraction pipe to the end of the inlet straight pipe section. The slope at the midpoint of the contraction section of the converging tube is given. A smooth streamlined curve can be quickly generated using this formula, ensuring a smooth and continuous transition between the inlet and outlet of the contraction section. This reduces flow resistance and intake losses in the contraction section. Simultaneously, this curve ensures a highly uniform airflow velocity distribution at the throat, avoiding fluctuations and instability during exhaust gas extraction. This improves the accuracy and system efficiency of EGR exhaust gas extraction and solves the problems of large variations in the inlet and outlet sections of currently used curves, resulting in significant flow resistance and intake losses, as well as uneven airflow distribution at the throat, all of which negatively impact the accuracy and efficiency of EGR exhaust gas extraction.

[0034] In some alternative embodiments, the end of the straight pipe section at the inlet of the contraction pipe is used as... The starting point for the directional design parameters is the centerline of the contraction tube. The starting point of the design parameters for the direction is based on the formula: Obtain the curve of the shrink tube cross-section; in, The radius of the straight pipe section at the outlet of the contraction pipe. The height of the contraction section of the contraction tube varies. The slope is the midpoint of the contraction section of the contraction tube.

[0035] In this embodiment, the end of the straight pipe section at the inlet of the contraction pipe is used as... The starting point for the directional design parameters is the centerline of the contraction tube. The starting point of the design parameters for the direction is based on the formula: Obtain the curve of the shrinkage tube cross-section; where, The radius of the straight pipe section at the outlet of the contraction pipe. The height of the contraction section of the contraction tube varies. The slope at the midpoint of the contraction section of the converging tube is given. Precise control of the contraction section geometry is achieved through dynamic iterative calculation. This formula progressively optimizes the curve based on the results of previous iterations, ensuring that the slope at the midpoint of the contraction section strictly matches the design parameters, avoiding curve distortion caused by fixed parameters in traditional design methods. This iterative calculation method makes the transition between the inlet and outlet of the contraction section smoother and more continuous, effectively eliminating flow separation and turbulence during the contraction process, and significantly reducing flow resistance and intake losses. Simultaneously, this formula can precisely control the midpoint position of the contraction section, simplifying the design process and improving design efficiency. Furthermore, by precisely optimizing the geometry of the contraction section, the airflow velocity distribution at the throat is made more uniform and stable, significantly improving the accuracy and system efficiency of EGR exhaust gas extraction. This solves the problems of large variations in the inlet and outlet sections of the curves currently used in existing technologies, resulting in significant flow resistance and intake losses, and uneven airflow distribution at the throat, all of which affect the accuracy and system efficiency of EGR exhaust gas extraction.

[0036] In this example, Figure 2 Point A is the mark at the end of the straight pipe section at the inlet of the contraction pipe, point B is the starting point of the contraction section of the contraction pipe, point C is the midpoint of the contraction section of the contraction pipe, point D is the ending point of the contraction section of the contraction pipe, and point E is the mark at the end of the straight pipe section at the outlet of the contraction pipe.

[0037] In some optional embodiments, the preset slope of the midpoint of the contraction section of the contraction tube based on its installation position includes: Based on the installation location of the shrink tube, obtain information on the interference between the shrink tube and other components; Based on the interference between the shrink tube and other components, the slope of the midpoint of the shrink section of the shrink tube is preset.

[0038] In this embodiment, based on the installation position of the contraction tube, the midpoint slope of the contraction section of the contraction tube is preset. Specifically, this includes: obtaining the interference between the contraction tube and other components based on the installation position of the contraction tube; and preseting the midpoint slope of the contraction section of the contraction tube based on the interference between the contraction tube and other components. By systematically evaluating the interference relationships of components in the actual installation space, it is ensured that the preset midpoint slope of the contraction section strictly matches the actual assembly conditions. This slope preset based on actual interference effectively avoids conflicts between the design and installation stages, eliminates geometric distortion of the contraction section caused by space constraints, and makes the transition of the flow channel in the contraction section smoother and more continuous. At the same time, this method significantly reduces the flow resistance of the airflow in the inlet and outlet regions of the contraction section, reduces local turbulence and flow separation caused by interference, and fundamentally improves the uniformity of airflow distribution at the throat.

[0039] In some optional embodiments, when the slope of the midpoint of the contraction section of the contraction tube is preset, the slope of the midpoint of the contraction section of the contraction tube is obtained based on an empirical table corresponding to the installation position of the contraction tube and the slope of the midpoint of the contraction section of the contraction tube.

[0040] In this embodiment, when presetting the slope of the midpoint of the contraction section of the shrink tube, the slope is obtained based on an empirical table corresponding to the installation position of the shrink tube and the slope of the midpoint of the contraction section. Since the empirical table integrates historical design data with spatial layout characteristics in actual installation scenarios, the slope presetting process does not rely on complex calculations or repeated trial and error, significantly shortening the design cycle and improving design efficiency.

[0041] like Figure 1 , Figure 4 and Figure 5 As shown, this application also provides a venturi tube, which is designed using the above-mentioned venturi tube design method for an EGR system.

[0042] When designing the Venturi tube for an EGR system, the slope of the midpoint of the contraction section is preset based on the installation position of the contraction tube. The curve of the contraction tube cross-section is obtained based on this slope, the radius of the outlet straight pipe section, the height variation of the contraction section, and the distance from the midpoint of the contraction section to the end of the inlet straight pipe section. The contraction tube is then designed based on this curve. Because the curve of the contraction tube cross-section is obtained based on the midpoint slope of the contraction section, the radius of the outlet straight pipe section, the height variation of the contraction section, and the distance from the midpoint of the contraction section to the end of the inlet straight pipe section, it exhibits better continuity and smoother curves compared to currently used curves. This solves the problems of large variations in the inlet and outlet sections of currently used curves, resulting in significant flow resistance and intake losses, as well as uneven airflow distribution at the throat, all of which affect the accuracy of EGR exhaust gas extraction and system efficiency.

[0043] On the one hand, this application also provides an EGR system, which includes the aforementioned Venturi tube.

[0044] When designing the Venturi tube for an EGR system, the slope of the midpoint of the contraction section is preset based on the installation position of the contraction tube. The curve of the contraction tube cross-section is obtained based on this slope, the radius of the outlet straight pipe section, the height variation of the contraction section, and the distance from the midpoint of the contraction section to the end of the inlet straight pipe section. The contraction tube is then designed based on this curve. Because the curve of the contraction tube cross-section is obtained based on the midpoint slope of the contraction section, the radius of the outlet straight pipe section, the height variation of the contraction section, and the distance from the midpoint of the contraction section to the end of the inlet straight pipe section, it exhibits better continuity and smoother curves compared to currently used curves. This solves the problems of large variations in the inlet and outlet sections of currently used curves, resulting in significant flow resistance and intake losses, as well as uneven airflow distribution at the throat, all of which affect the accuracy of EGR exhaust gas extraction and system efficiency.

[0045] On the other hand, this application also provides a vehicle that includes the aforementioned EGR system.

[0046] When designing the Venturi tube for an EGR system, the slope of the midpoint of the contraction section is preset based on the installation position of the contraction tube. The curve of the contraction tube cross-section is obtained based on this slope, the radius of the outlet straight pipe section, the height variation of the contraction section, and the distance from the midpoint of the contraction section to the end of the inlet straight pipe section. The contraction tube is then designed based on this curve. Because the curve of the contraction tube cross-section is obtained based on the midpoint slope of the contraction section, the radius of the outlet straight pipe section, the height variation of the contraction section, and the distance from the midpoint of the contraction section to the end of the inlet straight pipe section, it exhibits better continuity and smoother curves compared to currently used curves. This solves the problems of large variations in the inlet and outlet sections of currently used curves, resulting in significant flow resistance and intake losses, as well as uneven airflow distribution at the throat, all of which affect the accuracy of EGR exhaust gas extraction and system efficiency.

[0047] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0048] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0049] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for designing a venturi tube for an EGR system, characterized in that, include: Based on the installation position of the shrink tube, the slope of the midpoint of the shrink section of the shrink tube is preset; Based on the slope of the midpoint of the contraction section of the contraction tube, the radius of the outlet straight section of the contraction tube, the height variation of the contraction section of the contraction tube, and the distance from the midpoint of the contraction section of the contraction tube to the end of the inlet straight section, the curve of the cross-section of the contraction tube is obtained. The shrink tube is designed based on the curve of the shrink tube cross-section.

2. The EGR system venturi tube design method as described in claim 1, characterized in that, The design of the shrink tube based on the curve of the shrink tube cross-section includes: Based on the curve of the shrink tube cross-section, the cross-sectional shape of the shrink tube is obtained; The shrink tube is designed based on its cross-sectional shape.

3. The EGR system venturi tube design method as described in claim 2, characterized in that, The design of the shrink tube based on its cross-sectional shape includes: Select the port shape of the shrink tube; The shrink tube is designed based on the selected port shape and cross-sectional shape of the shrink tube.

4. The venturi tube design method for an EGR system as described in claim 1, characterized in that, Using the end of the straight pipe section at the inlet of the contraction pipe as The starting point for the design parameters of the direction is the centerline of the contraction tube. The starting point of the design parameters for the direction is based on the formula: Obtain the curve of the cross-section of the contraction tube; in, The radius of the straight pipe section at the outlet of the contraction pipe is given. The height variation of the contraction section of the contraction tube. The distance is the distance from the midpoint of the contraction section of the contraction tube to the end of the inlet straight pipe section. The slope at the midpoint of the contraction section of the contraction tube is given.

5. The venturi tube design method for an EGR system as described in claim 1, characterized in that, Using the end of the straight pipe section at the inlet of the contraction pipe as The starting point for the design parameters of the direction is the centerline of the contraction tube. The starting point of the design parameters for the direction is based on the formula: Obtain the curve of the cross-section of the contraction tube; in, The radius of the straight pipe section at the outlet of the contraction pipe is given. The height variation of the contraction section of the contraction tube. The slope at the midpoint of the contraction section of the contraction tube is given.

6. The venturi tube design method for an EGR system as described in claim 1, characterized in that, The aforementioned method of presetting the slope of the midpoint of the contraction section of the contraction tube based on its installation position includes: Based on the installation position of the shrink tube, the interference between the shrink tube and other components is obtained; Based on the interference between the shrink tube and other components, the slope of the midpoint of the shrink section of the shrink tube is preset.

7. The venturi tube design method for an EGR system as described in claim 1, characterized in that, When the slope of the midpoint of the contraction section of the contraction tube is preset, the slope of the midpoint of the contraction section of the contraction tube is obtained based on an empirical table corresponding to the installation position of the contraction tube and the slope of the midpoint of the contraction section of the contraction tube.

8. A venturi tube, characterized in that, The design utilizes the Venturi tube design method for an EGR system as described in any one of claims 1-7.

9. An EGR system, characterized in that, Including a Venturi tube as described in claim 8.

10. A vehicle, characterized in that, Including an EGR system as described in claim 9.

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