A multi-layer vector gas port inclination angle parameterization design method

Abstract

This invention provides a parameterized design method for the tilt angle of a multi-layer vector air inlet. The method includes determining the inlet height H, inlet width W, inlet thickness t, and cylinder diameter D on the cylinder liner based on the basic structural parameters and performance requirements of an opposed piston two-stroke engine; defining the multi-layer vector air inlet as consisting of a direct current layer, an intermediate spacer, and a vortex layer, with the vortex layer located near the injector placement, and both the top surface of the direct current layer and the bottom surface of the vortex layer being planar; and calculating the specific structure of the inlet through the derivation of these steps. The parameterized design method for the tilt angle of the multi-layer vector air inlet described in this invention can gradually change the tilt angle of the vortex layer from 0° to a specified angle, thereby reducing the low-pressure region at the center of the in-cylinder vortex and improving scavenging efficiency while generating a sufficiently large vortex ratio.

Description

Technical Field

[0001] This invention belongs to the field of engine technology, and in particular relates to a parameterized design method for the tilt angle of multi-layer vector air inlets. Background Technology

[0002] The quality of the scavenging process in a opposed-piston two-stroke diesel engine directly affects its power, economy, and emissions characteristics. A good scavenging process should achieve the maximum fresh charge volume in the shortest possible time while consuming as little mechanical work as possible. Opposed-piston two-stroke diesel engines achieve direct-flow scavenging by opening and closing the intake and exhaust ports located at both ends of the cylinder through the movement of the intake and exhaust pistons. This effectively avoids the mixing of fresh charge and residual exhaust gas, thus improving the scavenging effect of the diesel engine. Direct-flow scavenging has high scavenging efficiency and organizes intake vortices (i.e., rotating fluid masses in a fluid). If the intake port angle is too small, vortices cannot be effectively organized; if the intake port angle is too large, the resulting vortex mass is large, and the vortex core area is large. Because the pressure at the center of the vortex core is low, the air density at the cylinder center is low, and residual exhaust gas tends to accumulate and is difficult to expel from the cylinder. If the intake port tilt angle is designed to be gradual, the direction of airflow entering the cylinder through the intake port will also be gradual, thus forming vortices of different sizes. This can effectively organize vortices and solve the problem of low air density at the cylinder center and the accumulation of residual exhaust gas in the cylinder due to a large tilt angle. Therefore, a parameterized design method for the vector intake port tilt angle is needed to achieve the gradual design of the intake port tilt angle. Summary of the Invention

[0003] In view of this, the present invention aims to propose a parameterized design method for the tilt angle of multi-layer vector air inlets to solve the problem of how to reduce the low-pressure region at the center of the cylinder vortex and improve scavenging efficiency.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] A parametric design method for the tilt angle of a multi-layer vector air inlet includes the following steps:

[0006] S1. Based on the basic structural parameters and performance requirements of the opposed piston two-stroke engine, determine the intake port height H, intake port width W, intake port thickness t, and cylinder diameter D located on the cylinder liner.

[0007] S2. Define the multi-layer vector air inlet as consisting of a direct current layer, an intermediate spacer, and a vortex layer. The vortex layer is located on the side closest to the injector placement position, and the top surface of the direct current layer and the bottom surface of the vortex layer are both planar.

[0008] S3. Based on the engine's intake air volume requirements, scavenging performance and other indicators, determine the intake port direct current layer height h1, intermediate interval layer height h2, and vortex layer height h3, and H = h1 + h2 + h3. Among them, the intermediate interval height h2 can be adjusted according to the actual needs of the engine, and h2 is 0.

[0009] S4. Establish a three-dimensional coordinate system on the cross-section of the cylinder liner;

[0010] S5. Design the coordinates of the left and right parts of the air intake and outlet;

[0011] S6. Define the tilt angle of the no-air-port section of the multi-layer vector air-port DC layer and the tilt angle of the air-port section of the multi-layer vector air-port vortex layer as α;

[0012] S7. Define the relationship between the inlet tilt angle α and the inlet height z-coordinate;

[0013] S8. Given the intake port height H, intake port width W, intake port thickness t, and cylinder diameter D, obtain the intake port DC layer structure.

[0014] S9. Define the equation of line segment PP1 as y = kx + b, and define the equation of the circle containing point P1 as x 2 +y 2 =D 2 The coordinates of P1 are Given a fixed intake port width W, intake port thickness t, and cylinder diameter D, solve for the relationship between the line segment intercept b and the tilt angle α.

[0015] S10. Substitute the solutions for k and b obtained in step S9 and the function α = f(z) of α with respect to z into step S8 to obtain the coordinates of point P1. It is a function that depends only on z, and the range of z is 0 to h3;

[0016] S11. Calculate the specific structure of the air intake by deriving the above steps.

[0017] Furthermore, the method for designing the coordinates of the left and right parts of the air inlet and outlet in S5 is as follows: the AB segment of the air inlet and the A1B1 segment of the outlet are the direct current layer; the BC segment of the air inlet and the B1C1 segment of the outlet are the vortex layer, where points S and S1 are any points on the AB segment of the air inlet and the A1B1 segment of the outlet in the direct current layer, and points P and P1 are any points on the BC segment of the air inlet and the B1C1 segment of the outlet in the vortex layer.

[0018] Furthermore, in S6, the inclination angle of the DC layer portion of the multi-layer vector air inlet is 0, and the inclination angle of the air inlet of the vortex layer portion of the multi-layer vector air inlet is defined as α. The method is as follows: a certain air inlet cross section RPP1R1 of the vortex layer, where points R and P are symmetrical about the y-axis, and points P and P1 are two corresponding points on the inlet BC section and outlet B1C1 section of the vortex layer portion, respectively. The angle between line segment PP1 and the y-axis is the air inclination angle α of the air inlet cross section.

[0019] Furthermore, the method for defining the relationship between the inlet tilt angle α and the inlet height z coordinate in S7 is as follows: the z coordinate at the interface between the inlet middle interval and the vortex layer is selected as 0, the positive z axis points to the injector installation position, and the range of the vortex layer tilt angle α is defined as 0 to α0, that is, the tilt angle is 0 at the interface between the inlet middle interval and the vortex layer, and the tilt angle is α0 at the lowest surface of the vortex layer, and α is a function only about z, that is, α = f(z), where f(z) can be any function, and the function f(z) is determined according to the actual requirements of the engine for the vortex ratio.

[0020] Furthermore, the method for obtaining the DC layer structure of the intake port in S8 is as follows: In the DC layer intake port section NSS1N1, points N and S are symmetrical about the y-axis. Points S and S1 are two corresponding points on the intake AB segment and the outlet A1B1 segment of the DC layer, respectively. Since the DC layer has no tilt angle, line segment SS1 is parallel to the y-axis; the length of the straight line segment between points N and S is the width W of the intake port, so the x-coordinates of points S and S1 are both W / 2; the length of line segment OS is the cylinder liner outer diameter, and the y-coordinate of point S is obtained by the Pythagorean theorem. The length of line segment OS1 is the cylinder diameter D. Using the Pythagorean theorem, the y-coordinate of point S1 is... Then the coordinates (x, y) of point S can be obtained. S y S )for Coordinates of point S1 for Furthermore, the z-coordinates of points S and S1 both range from -h1 to 0.

[0021] Furthermore, in S9, given a fixed intake port width W, intake port thickness t, and cylinder diameter D, the specific method for solving the relationship between the line segment intercept b and the tilt angle α is as follows: Define the equation of line segment PP1 as y = kx + b, and define the equation of the circle containing point P1 as x 2 +y 2 =D 2 By solving the system of equations, we can obtain the coordinates of the intersection point P1 of line segment PP1 and the circle containing point P1 in the first quadrant. for

[0022] The length of the straight line segment between points R and P is the width W of the air intake, therefore the x-coordinate of point P is W / 2; the length of line segment OP is the outer diameter of the cylinder liner, and by the Pythagorean theorem, the y-coordinate of point P is... The slope of the equation for line segment PP1 is k = cotα. The coordinates of point P are... Substituting k = cotα into the equation of line segment PP1, which is y = kx + b, and solving the equation yields... That is, given a fixed intake port width W, intake port thickness t, and cylinder diameter D, b is a function of α only.

[0023] Furthermore, the method for calculating the specific structure of the intake port in S11 is as follows: The coordinates (x, y) of the intake port segments AB, BC, and A1B1 obtained through calculations in S1-S10 are only related to the intake port height H, port width W, port thickness t, and cylinder diameter D, and are independent of the z-axis. Therefore, the curves of segments AB, BC, and A1B1 can be directly plotted in Creo software. The coordinates (x, y) of the intake port outlet segment B1C1 are a function of the z-coordinate only. Using Excel software, the coordinates of point P1 corresponding to z values ​​from 0 to h3 can be obtained. The distance step size of z can be determined according to specific needs, thereby obtaining the coordinates of a series of points P1. By importing the coordinate data of point P1 into Creo software, the curve of segment B1C1 can be obtained, which in turn yields the curves of the air inlet and outlet, thus revealing the specific structure of the air inlet.

[0024] Compared with existing technologies, the multi-layer vector air inlet tilt angle parameterization design method of the present invention has the following advantages:

[0025] (1) The multi-layer vector air port tilt angle parameter design method of the present invention can realize the air port vortex layer tilt angle gradually changing from 0° to a certain specified angle, thereby reducing the low pressure area of ​​the cylinder vortex center and improving the scavenging efficiency under the premise of generating a sufficiently large vortex ratio.

[0026] (2) The multi-layer vector air inlet tilt angle parameterization design method of the present invention can quickly obtain vector air inlet structures with different vortex ratios by changing the functional relationship of α=f(z), which greatly saves the design time of vector air inlet structures and realizes the rapid matching of combustion system by combining engine combustion chamber design, fuel injection system design, etc. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0028] Figure 1 This is a flowchart of the parameterized design method for the tilt angle of the layer vector air inlet according to an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of a cross-sectional view of a cylinder liner according to an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the cross-section of the cylinder liner according to an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the air inlet and air outlet according to an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the cross-section RPP1R1 as described in an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the cross section NSS1N1 described in an embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram of the air inlet structure according to an embodiment of the present invention. Detailed Implementation

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0036] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention 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 the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0037] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0038] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0039] A parameterized design method for the tilt angle of multi-layer vector air inlets, such as Figures 1 to 7 As shown, it includes the following steps:

[0040] S1. Based on the basic structural parameters and performance requirements of the opposed piston two-stroke engine, determine the port height H, port width W, port thickness t, and cylinder diameter D of the intake port located on the cylinder liner (see [reference] for port height H and width W). Figure 1 (Cylinder XOZ plane), see port thickness t and cylinder diameter D. Figure 2 ).

[0041] S2. Define the multi-layer vector air inlet as consisting of a direct current layer, an intermediate spacer, and a vortex layer. The vortex layer is located on the side closest to the injector placement position, and both the top surface of the direct current layer and the bottom surface of the vortex layer are planar. Figure 1 As shown.

[0042] S3. Based on the engine's intake air volume requirements, scavenging performance and other indicators, determine the intake port direct current layer height h1, intermediate interval layer height h2, and vortex layer height h3, and H = h1 + h2 + h3. Among them, the intermediate interval height h2 can be adjusted according to the actual needs of the engine, and h2 can be 0.

[0043] S4. Establish a three-dimensional coordinate system on the cross-section of the cylinder liner, with the Z-axis along the cylinder liner axis, such as... Figure 1 As shown; the XOY plane is the cross-section of the cylinder liner, and the inlet and outlet of the intake port are as follows. Figure 2 As shown.

[0044] S5, such as Figure 3 As shown, the dashed lines divide the air intake and outlet (XOZ plane) into left and right sections. Since the parametric design methods for both sides are the same, only the design steps for the right side of the air intake and outlet will be described here. Figure 3As shown, the AB section of the air inlet and the A1B1 section of the air outlet form the direct current layer; the BC section of the air inlet and the B1C1 section of the air outlet form the vortex layer. Points S and S1 are any points on the AB section of the air inlet and the A1B1 section of the air outlet in the direct current layer (i.e., the z-coordinates of the two points are the same), and points P and P1 are any points on the BC section of the air inlet and the B1C1 section of the air outlet in the vortex layer (i.e., the z-coordinates of the two points are the same).

[0045] S6. Define the tilt angle of the DC layer portion of the multi-layer vector air inlet as α (i.e., the tilt angle is 0), and the tilt angle of the vortex layer portion of the multi-layer vector air inlet as α. Figure 4 Let RPP1 be the cross-section of a certain air inlet in the vortex layer (a certain XOY plane, i.e., cross section RPP1R1). Points R and P are symmetrical about the y-axis. Points P and P1 are two corresponding points on the inlet BC segment and outlet B1C1 segment of the vortex layer, respectively. The angle between line segment PP1 and the y-axis is the air inlet tilt angle α of the air inlet cross-section.

[0046] S7. Define the relationship between the inlet tilt angle α and the z-coordinate (i.e., inlet height). Select the z-coordinate at the interface between the inlet's midpoint and the vortex layer as 0, with the positive z-axis pointing towards the injector installation position. Figure 1 As shown. The range of the vortex layer tilt angle α is defined as 0 to α0, that is, the tilt angle is 0 at the junction of the air inlet and the vortex layer, and 0 at the lowest surface of the vortex layer (see...). Figure 1 The tilt angle at point () is α0, and α is a function only of z, i.e., α = f(z), where f(z) can be any function, and the function f(z) is determined according to the actual requirements of the engine for the vortex ratio.

[0047] S8 Figure 5 Let N be the cross-section of a certain air inlet in the DC layer (a certain XOY plane, i.e., section NSS1N1). Points N and S are symmetrical about the y-axis. Points S and S1 are two corresponding points on the inlet AB segment and outlet A1B1 segment of the DC layer, respectively. Since the DC layer has no tilt angle (i.e., α = 0, and does not change with the z-axis), line segment SS1 is parallel to the y-axis. The length of the straight line segment between points N and S is the width W of the air inlet, therefore the x-coordinate of both points S and S1 is W / 2. The length of line segment OS is the cylinder liner outer diameter (i.e., cylinder diameter D + air inlet thickness t). By the Pythagorean theorem, the y-coordinate of point S is... The length of line segment OS1 is the cylinder diameter D. Using the Pythagorean theorem, the y-coordinate of point S1 is... Then the coordinates (x, y) of point S can be obtained. S y S )for Coordinates of point S1 for Furthermore, the z-coordinates of points S and S1 both range from -h1 to 0. That is, given that the intake port height H, intake port width W, intake port thickness t, and cylinder diameter D are determined, the structure of the DC layer portion of the intake port can be directly obtained.

[0048] S9. Define the equation of line segment PP1 as y = kx + b, and define the equation of the circle containing point P1 as x 2 +y 2 =D 2 By solving the system of equations, we can obtain the coordinates of the intersection point P1 of line segment PP1 and the circle containing point P1 in the first quadrant. for

[0049] like Figure 4 As shown, the length of the straight line segment between points R and P is the width W of the intake port, so the x-coordinate of point P is W / 2; the length of line segment OP is the cylinder liner outer diameter (i.e., cylinder diameter D + intake port thickness t), and by the Pythagorean theorem, the y-coordinate of point P is... The slope of the equation for line segment PP1 is k = cotα. The coordinates of point P are... Substituting k = cotα into the equation of line segment PP1, which is y = kx + b, and solving the equation yields... That is, given a fixed intake port width W, intake port thickness t, and cylinder diameter D, b is a function of α only.

[0050] S10. Substitute the solutions for k and b obtained in step S9 and the function α = f(z) of α with respect to z into step S8 to obtain the coordinates of point P1. It is a function that depends only on z, and the range of z is 0 to h3.

[0051] S11. Through the derivation and calculation of the above steps, it is finally concluded that the coordinates (x, y) of the intake AB segment, BC segment, and outlet A1B1 segment are only related to the intake port height H, port width W, port thickness t, and cylinder diameter D, and are independent of the z-axis. Therefore, the curves of the AB, BC, and A1B1 segments can be directly plotted in Creo software. The coordinates (x, y) of the intake outlet B1C1 segment are a function of the z-coordinate only. Using Excel software, the coordinates of point P1 corresponding to z values ​​from 0 to h3 can be obtained. The distance step size of z can be determined according to specific needs, thereby obtaining the coordinates of a series of points P1. Importing the coordinate data of point P1 into Creo software will yield the curve for segment B1C1. In summary, the inlet and outlet curves of the air intake can be obtained, thus revealing the specific structure of the air intake.

[0052] The following is an example:

[0053] S1. Based on the basic structural parameters and performance requirements of a certain opposed piston two-stroke engine, determine that the air inlet height H on the cylinder liner is 20mm, the air inlet width W is 25mm, the air inlet thickness t is 20mm, and the cylinder diameter D is 120mm.

[0054] S2. Define the multi-layer vector air inlet as consisting of a direct current layer, an intermediate spacer, and a vortex layer. The vortex layer is located on the side closest to the injector placement position, and both the top surface of the direct current layer and the bottom surface of the vortex layer are planar. Figure 1 As shown.

[0055] S3. Based on the selected engine's intake volume requirements, scavenging performance, and other indicators, determine the intake port direct current layer height h1 as 8, the intermediate interval height h2 as 0, and the vortex layer height h3 as 12.

[0056] S4. Establish a three-dimensional coordinate system on the cross-section of the cylinder liner, with the Z-axis along the cylinder liner axis, such as... Figure 1 As shown; the XOY plane is the cross-section of the cylinder liner, and the inlet and outlet of the intake port are as follows. Figure 2 As shown.

[0057] S5, such as Figure 3 As shown, the dashed lines divide the air intake and outlet (XOZ plane) into left and right sections. Since the parametric design methods for both sides are the same, only the design steps for the right side of the air intake and outlet will be described here. Figure 3 As shown, the AB section of the air inlet and the A1B1 section of the air outlet form the direct current layer; the BC section of the air inlet and the B1C1 section of the air outlet form the vortex layer. Points S and S1 are any points on the AB section of the air inlet and the A1B1 section of the air outlet in the direct current layer (i.e., the z-coordinates of the two points are the same), and points P and P1 are any points on the BC section of the air inlet and the B1C1 section of the air outlet in the vortex layer (i.e., the z-coordinates of the two points are the same).

[0058] S6. Define the tilt angle of the no-air-port section of the multi-layer vector air-port DC layer (i.e., the tilt angle is 0), and define the tilt angle of the air-port section of the multi-layer vector air-port vortex layer as α. Figure 4 Let RPP1 be the cross-section of a certain air inlet in the vortex layer (a certain XOY plane, i.e., cross section RPP1R1). Points R and P are symmetrical about the y-axis. Points P and P1 are two corresponding points on the inlet BC segment and outlet B1C1 segment of the vortex layer, respectively. The angle between line segment PP1 and the y-axis is the air inlet tilt angle α of the air inlet cross-section.

[0059] S7. Define the relationship between the inlet tilt angle α and the z-coordinate (i.e., inlet height). Select the z-coordinate at the interface between the direct current layer and the vortex layer of the inlet as 0, with the positive z-axis pointing towards the injector installation position. Figure 1As shown. The selected range for the vortex layer tilt angle α is 0–30°. In this embodiment, there is no intermediate gap at the air inlet, so the tilt angle is 0 at the junction of the direct current layer and the vortex layer at the air inlet, and at the lowest surface of the vortex layer (see...). Figure 1 The tilt angle at point () is 30°. The tilt angle α of the inlet vortex layer is defined as a linear function of z, and... Therefore, the function of α with respect to z is: (The value of z ranges from 0 to 12).

[0060] S8 Figure 5 Let N be the cross-section of a certain air inlet in the DC layer (a certain XOY plane, i.e., section NSS1N1). Points N and S are symmetrical about the y-axis. Points S and S1 are two corresponding points on the inlet AB segment and outlet A1B1 segment of the DC layer, respectively. Since the DC layer has no tilt angle (i.e., α = 0, and does not change with the z-axis), line segment SS1 is parallel to the y-axis. Substituting the inlet height H = 20mm, inlet width W = 25mm, inlet thickness t = 20mm, and cylinder diameter D = 120mm into the coordinates of points S and S1, we obtain:

[0061]

[0062] Furthermore, the z-coordinates of points S and S1 range from -8 to 0.

[0063] S9. Define the equation of line segment PP1 as y = kx + b. For example... Figure 4 As shown, the length of the straight line segment between points R and P is the width W of the intake port, so the x-coordinate of point P is W / 2; the length of line segment OP is the cylinder liner outer diameter (i.e., cylinder diameter D + intake port thickness t), and by the Pythagorean theorem, the y-coordinate of point P is... The slope of the equation for line segment PP1 is k = cotα. The coordinates of point P are... and Substituting the equation of line segment PP1 into the expression y = kx + b, we can solve the equation to obtain... Substituting the inlet height H = 20mm, inlet width W = 25mm, inlet thickness t = 20mm, and cylinder diameter D = 120mm into the coordinates of point P and the expression for b, we obtain:

[0064]

[0065] S10. Substitute the solutions for k and b, and the function of α with respect to z, into the coordinates of point P1. Conclusion:

[0066]

[0067]

[0068] The value of z ranges from 0 to 12.

[0069] S11. Through the derivation and calculation of the above steps, it is finally concluded that the coordinates (x, y) of the intake AB segment, BC segment, and outlet A1B1 segment are only related to the intake port height H, port width W, port thickness t, and cylinder diameter D, and are independent of the z-axis. Therefore, the curves of the AB, BC, and A1B1 segments can be directly plotted in Creo software. The coordinates (x, y) of the intake outlet B1C1 segment are a function of the z-coordinate only. Using Excel software, the coordinates of point P1 corresponding to z values ​​from 0 to 12 can be obtained. The distance step size of z is selected as 0.001, thus obtaining the coordinates of a series of points P1. Importing the coordinate data of point P1 into Creo software will yield the curve for segment B1C1. In summary, the inlet and outlet curves of the air intake can be obtained, thus revealing the specific structure of the air intake. Figure 6 The image shows the specific structure of the air intake obtained in this embodiment (the structure has been rounded).

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A parameterized design method for the tilt angle of a multi-layer vector air inlet, characterized in that: Includes the following steps: S1. Based on the basic structural parameters and performance requirements of the opposed piston two-stroke engine, determine the intake port height H, intake port width W, intake port thickness t, and cylinder diameter D located on the cylinder liner. S2. Define the multi-layer vector air inlet as consisting of a direct current layer, an intermediate spacer, and a vortex layer. The vortex layer is located on the side closest to the injector placement position, and the top surface of the direct current layer and the bottom surface of the vortex layer are both planar. S3. Based on the engine's intake air volume requirements and scavenging performance, determine the intake inlet direct current layer height h1, intermediate spacer layer height h2, and vortex layer height h3, and... Among them, the intermediate interval height h2 is adjusted according to the actual needs of the engine, and h2 is 0; S4. Establish a three-dimensional coordinate system on the cross-section of the cylinder liner; S5. Design the coordinates of the left and right parts of the air intake and outlet; S6. Define the inclination angle of the non-inlet portion of the DC layer of the multi-layer vector air inlet and the inclination angle of the inlet portion of the vortex layer of the multi-layer vector air inlet as follows: ; S7, Define the air inlet tilt angle The z-coordinate relationship with the height of the air intake; S8. Given the intake port height H, intake port width W, intake port thickness t, and cylinder diameter D, obtain the intake port DC layer structure. S9. Define the equation of line segment PP1 as y = kx + b, and define the equation of the circle containing point P1 as... The coordinates of P1 are ( , Given a fixed intake port width W, intake port thickness t, and cylinder diameter D, solve for the line segment intercept b and the tilt angle. Relationship; S10. The solutions for k and b obtained in step S9 and Functions of z Substituting into step S8, the coordinates of point P1 are obtained ( , ) is a function that depends only on z, and the range of z is 0 to h3; S11. Calculate the specific structure of the air intake; The method for designing the coordinates of the left and right parts of the air inlet and outlet in S5 is as follows: the AB segment of the air inlet and the A1B1 segment of the outlet are the direct current layer; the BC segment of the air inlet and the B1C1 segment of the outlet are the vortex layer. Points S and S1 are any points on the AB segment of the air inlet and the A1B1 segment of the outlet in the direct current layer, respectively, and points P and P1 are any points on the BC segment of the air inlet and the B1C1 segment of the outlet in the vortex layer, respectively. The air inlet tilt angle is defined in S7. The method for determining the relationship between the intake port height and the z-coordinate is as follows: The z-coordinate at the interface between the intake port's midpoint and the vortex layer is set to 0, with the positive z-axis pointing towards the injector installation position. The vortex layer tilt angle is then defined. The value range is 0~ That is, the tilt angle is 0 at the junction of the air inlet and the vortex layer, and the tilt angle is at the lowest surface of the vortex layer. ,and It is a function only of z, that is ,in The function is arbitrary and is determined based on the engine's actual requirements for the vortex ratio. ; The method for calculating the specific structure of the intake port in S11 is as follows: The coordinates (x, y) of the intake port segments AB, BC, and A1B1 obtained through calculations in S1-S10 are only related to the intake port height H, port width W, port thickness t, and cylinder diameter D, and are independent of the z-axis. Therefore, the curves of segments AB, BC, and A1B1 are directly plotted in Creo software. The coordinates (x, y) of the intake port outlet segment B1C1 are a function of the z-coordinate only. Using Excel software, the coordinates of point P1 corresponding to z values ​​from 0 to h3 are obtained. , The distance step size of z can be determined according to specific needs, thereby obtaining the coordinates of a series of points P1. , , By importing the coordinate data of point P1 into Creo software, the curve of segment B1C1 can be obtained, which in turn yields the curves of the air inlet and outlet, thus revealing the specific structure of the air inlet.

2. The method for parameterizing the tilt angle of a multi-layer vector air inlet according to claim 1, characterized in that: In S6, the tilt angle of the no-inlet section of the multi-layer vector inlet direct current layer is defined as 0, and the tilt angle of the inlet section of the multi-layer vector inlet vortex layer is defined as... The method is as follows: Consider a cross-section RPP1R1 of an air inlet in the vortex layer, where points R and P are symmetrical about the y-axis. Points P and P1 are two corresponding points on the inlet BC segment and outlet B1C1 segment of the vortex layer, respectively. The angle between line segment PP1 and the y-axis is the air inlet tilt angle of the cross-section. .

3. The parameterized design method for the tilt angle of a multi-layer vector air inlet according to claim 1, characterized in that: The method for obtaining the DC layer structure of the intake port in S8 is as follows: In the DC layer intake port section NSS1N1, points N and S are symmetrical about the y-axis. Points S and S1 are two corresponding points on the intake AB segment and the outlet A1B1 segment of the DC layer, respectively. Since the DC layer has no tilt angle, line segment SS1 is parallel to the y-axis. The length of the straight line segment between points N and S is the width W of the intake port, so the x-coordinates of points S and S1 are both W / 2. The length of line segment OS is the cylinder liner outer diameter. By the Pythagorean theorem, the y-coordinate of point S is... The length of line segment OS1 is equal to the cylinder diameter D. Using the Pythagorean theorem, the y-coordinate of point S1 is... ; and then the coordinates of point S are obtained ( , ) is (W / 2, The coordinates of point S1 are ( , ) is (W / 2, ), and the z coordinates of points S and S1 both range from -h1 to 0.

4. The method for parameterizing the tilt angle of a multi-layer vector air inlet according to claim 1, characterized in that: In S9, given a fixed intake port width W, intake port thickness t, and cylinder diameter D, solve for the line segment intercept b and the tilt angle. The specific method for defining the relationship is as follows: Define the equation of line segment PP1 as y = kx + b, and define the equation of the circle containing point P1 as... Solve the system of equations by combining the two equations to obtain the coordinates of the intersection point P1 of line segment PP1 and the circle containing point P1 in the first quadrant. , )for( , ); The length of the straight line segment between points R and P is the width W of the air intake, therefore the x-coordinate of point P is W / 2; the length of line segment OP is the outer diameter of the cylinder liner, and by the Pythagorean theorem, the y-coordinate of point P is... The slope k of the equation for line segment PP1 is... The coordinates of point P are (W / 2, ) and k= Substituting the equation of line segment PP1 into the expression y=kx+b, we can solve the equation to obtain... That is, given that the intake port width W, intake port thickness t, and cylinder diameter D are fixed, b is only related to... The function.

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