Multilayer vector gas port inclination angle parameterization design method

Abstract

The invention provides a multilayer vector air port inclination angle parameterization design method which comprises the following steps: determining the height H, the width W, the thickness t and the cylinder diameter D of an air inlet in a cylinder sleeve according to basic structure parameters and performance requirements of an opposed piston two-stroke engine; the multi-layer vector air port is defined to be composed of a direct flow layer, a middle interval and a vortex layer, the vortex layer is located on the side close to the oil sprayer placing position, and the topmost face of the direct flow layer and the lowest face of the vortex layer are both planes. And the specific structure of the air inlet is calculated through derivation of the steps. According to the parameterization design method for the inclination angle of the multi-layer vector air port, the inclination angle of the vortex layer of the air port can be gradually changed from 0 degree to a certain specified angle, and therefore on the premise that the vortex ratio which is large enough is generated, the low-pressure area of the vortex center in a cylinder is reduced, and the scavenging efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of engines, and in particular relates to a parameterized design method for the inclination angle of a multi-layer vector air port. Background Art

[0002] The quality of the scavenging process of an opposed piston two-stroke diesel engine directly affects the power, economy and emission characteristics of the engine. A good scavenging process should be able to obtain the maximum amount of fresh air in the shortest time while consuming as little mechanical work as possible. The opposed piston two-stroke diesel engine realizes direct scavenging by opening and closing the intake and exhaust ports arranged at both ends of the cylinder through the movement of the intake and exhaust pistons, which can effectively avoid the mutual mixing of fresh charge and residual exhaust gas, thereby improving the scavenging effect of the diesel engine. Direct scavenging has high scavenging efficiency and organizes intake vortex (i.e., a rotating fluid mass in the fluid). If the intake inclination angle of the intake port is small, the vortex cannot be effectively organized; if the intake inclination angle is too large, the vortex mass generated is larger, and the vortex core area is larger. Because the pressure at the center of the vortex core is low, the air density at the center of the cylinder is low, and the residual exhaust gas is easy to gather and difficult to discharge from the cylinder. If the inlet inclination angle is designed to be gradual, the direction of the airflow entering the cylinder through the inlet will be gradual, thus forming vortex groups of different sizes, which can effectively organize the vortex and solve the problem of low air density in the center of the cylinder and easy accumulation of residual exhaust gas due to too large an inclination angle. Therefore, a vector inlet inclination angle parameterized design method is needed to realize the gradual design of the inlet inclination angle. Summary of the invention

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

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

[0005] A multi-layer vector gas port inclination angle parameterized design method includes the following steps:

[0006] S1. According to the basic structural parameters and performance requirements of the opposed piston two-stroke engine, determine the air inlet height H, air inlet width W, air inlet thickness t and cylinder diameter D on the cylinder liner;

[0007] S2. Define that the multi-layer vector gas port is composed of a DC layer, an intermediate interval, and an eddy current layer. The eddy current layer is located on the side close to the injector placement position, and the top surface of the DC layer and the bottom surface of the eddy current layer are both planes;

[0008] S3. Determine the inlet straight layer height h1, the middle interval layer height h2, and the eddy layer height h3 in combination with the engine's intake volume demand, scavenging performance and other indicators, and H = h1 + h2 + h3, where the middle 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 inlet and outlet;

[0011] S6, defining the inclination angle of the non-inlet part of the multi-layer vector air inlet DC layer and the inclination angle of the air inlet part of the multi-layer vector air inlet eddy layer as α;

[0012] S7, defining the relationship between the air inlet inclination angle α and the air inlet height z coordinate;

[0013] S8. When the air inlet height H, the air inlet width W, the air inlet thickness t and the cylinder diameter D are determined, the air inlet DC layer structure is obtained;

[0014] S9. The equation for defining line segment PP1 is y=kx+b, and the equation for defining the circle where point P1 is located is x 2 +y 2 =D 2 , the coordinates of P1 are When the inlet width W, inlet thickness t, and cylinder diameter D are determined, the relationship between the line segment intercept b and the inclination angle α is solved;

[0015] S10, substitute the solution of k, b and the function of α with respect to z α=f(z) obtained in step S9 into step S8, and the coordinates of point P1 obtained are It is a function related only to z, and the value range of z is 0~h3;

[0016] S11. Calculate the specific structure of the air inlet through the derivation of 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: the AB segment of the air inlet and the A1B1 segment of the outlet are the DC layer; the BC segment of the air inlet and the B1C1 segment of the outlet are the vortex layer, wherein point S and point S1 are respectively any points corresponding to the AB segment of the air inlet and the A1B1 segment of the outlet in the DC layer part, and point P and point P1 are respectively any points corresponding to the BC segment of the air inlet and the B1C1 segment of the outlet in the vortex layer part.

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

[0019] Furthermore, the method for defining the relationship between the air port inclination angle α and the air inlet height z coordinate in S7 is: select the z coordinate at the interface between the middle interval of the air inlet and the vortex layer as 0, the positive direction of the z axis points to the injector installation position, and define the value range of the vortex layer inclination angle α as 0 to α0, that is, the inclination angle at the interface between the middle interval of the air inlet and the vortex layer is 0, and the inclination angle at the lowest surface of the vortex layer is α0, and α is a function only about z, that is, α=f(z), where f(z) can be an arbitrary function, and the function f(z) is determined according to the actual demand of the engine for the swirl ratio.

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

[0021] Furthermore, in the above S9, when the air inlet width W, the air inlet thickness t, and the cylinder diameter D are determined, the specific method for solving the relationship between the line segment intercept b and the inclination angle α is: the equation expression of the line segment PP1 is defined as y=kx+b, and the equation expression of the circle where the point P1 is located is defined as x 2 +y 2 =D 2 , combine the two equations, solve the equation system to get the coordinates of the intersection point P1 of the line segment PP1 and the circle where point P1 is located in the first quadrant for

[0022] The length of the straight line segment between point R and point P is the width W of the air inlet, so the x coordinate of point P is W / 2; the length of line segment OP is the outer diameter of the cylinder liner, and the y coordinate of point P is obtained from the Pythagorean theorem: The slope of the equation of line segment PP1 is k = cotα, and the coordinates of point P are Substituting k=cotα into the equation of line segment PP1 is y=kx+b, and solving the equation yields That is, when the intake port width W, intake port thickness t, and cylinder diameter D are determined, b is a function of only α.

[0023] Furthermore, the method for calculating the specific structure of the air inlet in S11 is as follows: through the calculation of S1-S10, it is obtained that the coordinates (x, y) of the air inlet inlet segment AB, segment BC and outlet segment A1B1 are only related to the air inlet height H, air inlet width W, air inlet thickness t, and cylinder diameter D of the air inlet, and have nothing to do with the z coordinate axis, and thus the curves of the AB segment, BC segment and A1B1 segment can be directly drawn in the Creo software; the coordinates (x, y) of the air inlet outlet segment B1C1 are functions only about the z coordinate, and the coordinates of the point P1 corresponding to the z value from 0 to h3 can be obtained using the Excel software. The discrete step length of z can be determined according to specific needs, and then the coordinates of a series of points P1 can be obtained. By importing the coordinate data of point P1 into Creo software, the curve of segment B1C1 can be obtained, and the curves of the inlet and outlet of the air inlet can be obtained, and then the specific structure of the air inlet can be obtained.

[0024] Compared with the prior art, the multi-layer vector gas port inclination angle parameterized design method of the present invention has the following advantages:

[0025] (1) The multi-layer vector air inlet inclination angle parameterized design method described in the present invention can realize the gradual change of the inclination angle of the air inlet vortex layer from 0° to a certain specified angle, thereby reducing the low-pressure area in the center of the vortex in the cylinder and improving the scavenging efficiency under the premise of generating a sufficiently large swirl ratio.

[0026] (2) The multi-layer vector air port inclination angle parameterized design method described in the present invention can quickly obtain vector air port structures with different swirl ratios by changing the functional relationship of α=f(z), thereby greatly saving the design time of the vector air port structure and realizing rapid matching of the combustion system in combination with the engine combustion chamber design, the injection system design, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0028] Figure 1 It is a flow chart of the parameterized design method of the layer vector gas port inclination angle according to an embodiment of the present invention;

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

[0030] Figure 3 A schematic cross-sectional view of a cylinder liner according to an embodiment of the present invention;

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

[0032] Figure 5 A schematic diagram of a cross-section RPP1R1 according to an embodiment of the present invention;

[0033] Figure 6 is a schematic diagram of a cross section NSS1N1 according to an embodiment of the present invention;

[0034] Figure 7 It is a schematic diagram of the structure of the air inlet according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

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

[0039] A multi-layer vector gas port inclination angle parameterized design method, such as Figures 1 to 7 As shown, the following steps are included:

[0040] S1. According to the basic structural parameters and performance requirements of the opposed piston two-stroke engine, determine the air inlet height H, air inlet width W, air inlet thickness t, and cylinder diameter D (the air inlet height H and width W are shown in Figure 1 (cylinder XOZ plane), port thickness t and cylinder diameter D see Figure 2 ).

[0041] S2. Define that the multi-layer vector gas port consists of a DC layer, an intermediate interval, and an eddy current layer. The eddy current layer is located on the side close to the injector placement position, and the top surface of the DC layer and the lowest surface of the eddy current layer are both planes, such as Figure 1 shown.

[0042] S3. Combined with the engine's air intake demand, scavenging performance and other indicators, determine the air intake straight layer height h1, the middle interval layer height h2, and the eddy layer height h3, and H = h1 + h2 + h3, where the middle 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 axis of the cylinder liner, such as Figure 1 As shown; the XOY plane is the cross section of the cylinder liner, and the inlet and outlet of the air inlet are as shown Figure 2 shown.

[0044] S5, such as Figure 3 As shown in the figure, the dotted line divides the air inlet and outlet (XOZ plane) into two parts, left and right. Since the parametric design methods for the left and right sides are the same, only the design steps for the right side of the air inlet and outlet are introduced here; Figure 3As shown, the AB segment of the air inlet and the A1B1 segment of the outlet are the DC layer; the BC segment of the air inlet and the B1C1 segment of the outlet are the vortex layer, wherein point S and point S1 are the corresponding arbitrary points on the AB segment of the air inlet and the A1B1 segment of the outlet of the DC layer part (i.e., the z coordinates of the two points are the same), and point P and point P1 are the corresponding arbitrary points on the BC segment of the air inlet and the B1C1 segment of the outlet of the vortex layer part (i.e., the z coordinates of the two points are the same).

[0045] S6. Define that the DC layer portion of the multi-layer vector air inlet has no air inlet inclination angle (i.e., the inclination angle is 0), and the air inlet in the vortex layer portion of the multi-layer vector air inlet has an inclination angle of α. Figure 4 is a cross section of a gas outlet of the vortex layer (a certain XOY plane, i.e., cross section RPP1R1). Point R and point P are symmetrical about the y-axis, and point P and point P1 are two corresponding points on the BC segment of the gas inlet and the B1C1 segment of the outlet of the vortex layer, respectively. The angle between the line segment PP1 and the y-axis is the gas outlet inclination angle α of the gas outlet cross section.

[0046] S7. Define the relationship between the inlet inclination angle α and the z coordinate (i.e., the inlet height). Select the z coordinate at the interface between the middle interval of the inlet and the vortex layer as 0, and the positive direction of the z axis points to the injector installation position, such as Figure 1 The value range of the vortex layer inclination angle α is defined as 0 to α0, that is, the inclination angle is 0 at the junction of the middle interval of the air inlet and the vortex layer, and the inclination angle is 0 at the lowest surface of the vortex layer (see Figure 1 ) is α0, and α is a function only about z, that is, α=f(z), where f(z) can be an arbitrary function, and the function f(z) is determined according to the actual demand of the engine for the swirl ratio.

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

[0048] S9. The equation for defining line segment PP1 is y=kx+b, and the equation for defining the circle where point P1 is located is x 2 +y 2 =D 2 , combine the two equations, solve the equation system to get the coordinates of the intersection point P1 of the line segment PP1 and the circle where point P1 is located in the first quadrant for

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

[0050] S10, substitute the solution of k, b and the function of α with respect to z α=f(z) obtained in step S9 into step S8, and the coordinates of point P1 obtained are It is a function that is only related to z, and the value 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 inlet AB segment, BC segment and outlet A1B1 segment are only related to the inlet height H, inlet width W, inlet thickness t, and cylinder diameter D of the inlet, and have nothing to do with the z coordinate axis. Therefore, the curves of the AB segment, BC segment and A1B1 segment can be directly drawn in the Creo software; the coordinates (x, y) of the inlet outlet B1C1 segment are functions only about the z coordinate. Using the Excel software, the coordinates of the point P1 corresponding to the z value from 0 to h3 can be obtained. The discrete step length of z can be determined according to specific needs, and then the coordinates of a series of points P1 can be obtained. Import the coordinate data of point P1 into Creo software to get the curve of segment B1C1. In summary, the curves of the inlet and outlet of the air inlet can be obtained, and then the specific structure of the air inlet can be obtained.

[0052] The examples are as follows:

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

[0054] S2. Define that the multi-layer vector gas port consists of a DC layer, an intermediate interval, and an eddy current layer. The eddy current layer is located on the side close to the injector placement position, and the top surface of the DC layer and the lowest surface of the eddy current layer are both planes, such as Figure 1 shown.

[0055] S3. Based on the air intake demand, scavenging performance and other indicators of the selected engine, determine that the air intake straight layer height h1 is 8, the middle interval height h2 is 0, and the vortex layer height h3 is 12.

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

[0057] S5, such as Figure 3 As shown in the figure, the dotted line divides the air inlet and outlet (XOZ plane) into two parts, left and right. Since the parametric design methods for the left and right sides are the same, only the design steps for the right side of the air inlet and outlet are introduced here; Figure 3 As shown, the AB segment of the air inlet and the A1B1 segment of the outlet are the DC layer; the BC segment of the air inlet and the B1C1 segment of the outlet are the vortex layer, wherein point S and point S1 are the corresponding arbitrary points on the AB segment of the air inlet and the A1B1 segment of the outlet of the DC layer part (i.e., the z coordinates of the two points are the same), and point P and point P1 are the corresponding arbitrary points on the BC segment of the air inlet and the B1C1 segment of the outlet of the vortex layer part (i.e., the z coordinates of the two points are the same).

[0058] S6. Define that the DC layer portion of the multi-layer vector air inlet has no air inlet inclination angle (i.e., the inclination angle is 0), and define the air inlet inclination angle of the eddy layer portion of the multi-layer vector air inlet as α. Figure 4 is a cross section of a gas outlet of the vortex layer (a certain XOY plane, i.e., cross section RPP1R1). Point R and point P are symmetrical about the y-axis, and point P and point P1 are two corresponding points on the BC segment of the gas inlet and the B1C1 segment of the outlet of the vortex layer, respectively. The angle between the line segment PP1 and the y-axis is the gas outlet inclination angle α of the gas outlet cross section.

[0059] S7. Define the relationship between the inlet inclination angle α and the z coordinate (i.e., the inlet height). Select the z coordinate at the interface between the direct current layer and the eddy current layer of the inlet as 0, and the positive direction of the z axis points to the injector installation position, such as Figure 1The selected vortex layer inclination angle α is in the range of 0 to 30°. In this embodiment, the air inlet has no intermediate interval, so the inclination angle at the junction of the direct current layer and the vortex layer at the air inlet is 0, and at the lowest surface of the vortex layer (see Figure 1 ) is 30°, and the function of the inlet vortex layer inclination angle α with respect to z is defined as a linear function, and Then we can conclude that the function of α with respect to z is (The value range of z is 0 to 12).

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

[0061]

[0062] And the z coordinates of point S and point S1 range from -8 to 0.

[0063] S9. Define the equation of line segment PP1 as y=kx+b. Figure 4 As shown, the length of the straight line segment between point R and point P is the width W of the air inlet, so the x coordinate of point P is W / 2; the length of line segment OP is the outer diameter of the cylinder liner (i.e., cylinder diameter D + air inlet thickness t), and the y coordinate of point P is obtained from the Pythagorean theorem: The slope of the equation of line segment PP1 is k = cotα, and the coordinates of point P are and Substituting the equation of line segment PP1 into y=kx+b, solving the equation yields Substituting the air inlet height H = 20 mm, air inlet width W = 25 mm, air inlet thickness t = 20 mm, and cylinder diameter D = 120 mm into the expressions of the coordinates of point P and b, we obtain:

[0064]

[0065] S10, substitute the solution of k, b and the function of α with respect to z into the coordinates of point P1 It turns out that:

[0066]

[0067]

[0068] The value range of z is 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 inlet AB segment, BC segment and outlet A1B1 segment are only related to the inlet height H, inlet width W, inlet thickness t, and cylinder diameter D of the inlet, and have nothing to do with the z coordinate axis. Therefore, the curves of the AB segment, BC segment and A1B1 segment can be directly drawn in the Creo software; the coordinates (x, y) of the inlet outlet B1C1 segment are functions only about the z coordinate. Using the Excel software, the coordinates of the point P1 corresponding to the z value from 0 to 12 can be obtained. The discrete step length of z is selected as 0.001, and then the coordinates of a series of points P1 are obtained. Import the coordinate data of point P1 into Creo software to get the curve of segment B1C1. In summary, the curves of the inlet and outlet of the air inlet can be obtained, and then the specific structure of the air inlet can be obtained. Figure 6 The figure shows the specific structure of the air inlet obtained in this embodiment (the structure is 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-layer vector gas port inclination angle parameterized design method, characterized in that: The following steps are involved: S1. According to the basic structural parameters and performance requirements of the opposed piston two-stroke engine, determine the air inlet height H, air inlet width W, air inlet thickness t and cylinder diameter D on the cylinder liner; S2. Define that the multi-layer vector gas port is composed of a DC layer, an intermediate interval, and an eddy current layer. The eddy current layer is located on the side close to the injector placement position, and the top surface of the DC layer and the bottom surface of the eddy current layer are both planes; S3. Determine the inlet straight layer height h1, the middle interval layer height h2, and the eddy layer height h3 in combination with the engine's intake volume demand, scavenging performance and other indicators, and H = h1 + h2 + h3, where the middle interval height h2 can be 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 inlet and outlet; S6, defining the inclination angle of the non-inlet part of the multi-layer vector air inlet DC layer and the inclination angle of the air inlet part of the multi-layer vector air inlet eddy layer as α; S7, defining the relationship between the air inlet inclination angle α and the air inlet height z coordinate; S8. When the air inlet height H, the air inlet width W, the air inlet thickness t and the cylinder diameter D are determined, the air inlet DC layer structure is obtained; S9. The equation for defining line segment PP1 is y=kx+b, and the equation for defining the circle where point P1 is located is x 2 +y 2 =D 2 , the coordinates of P1 are When the inlet width W, inlet thickness t, and cylinder diameter D are determined, the relationship between the line segment intercept b and the inclination angle α is solved; S10, substitute the solution of k, b and the function of α with respect to z α=f(z) obtained in step S9 into step S8, and the coordinates of point P1 obtained are It is a function related only to z, and the value range of z is 0~h3; S11. Calculate the specific structure of the air inlet.

2. A multi-layer vector gas port inclination angle parameterized design method according to claim 1, characterized in that: The method for designing the coordinates of the left and right parts of the air inlet and outlet in S5 is: the AB segment of the air inlet and the A1B1 segment of the outlet are the DC layer; the BC segment of the air inlet and the B1C1 segment of the outlet are the vortex layer, wherein point S and point S1 are the corresponding arbitrary points on the AB segment of the air inlet and the A1B1 segment of the outlet of the DC layer part, respectively, and point P and point P1 are the corresponding arbitrary points on the BC segment of the air inlet and the B1C1 segment of the outlet of the vortex layer part.

3. A multi-layer vector gas port inclination angle parameterized design method according to claim 1, characterized in that: In S6, the inclination angle of the DC layer part of the multi-layer vector air inlets is 0, and the method of defining the inlet inclination angle of the vortex layer part of the multi-layer vector air inlets is α: a certain air inlet cross section RPP1R1 of the vortex layer, where point R and point P are symmetrical about the y-axis, point P and point P1 are two corresponding points on the BC segment of the air inlet and the B1C1 segment of the outlet of the vortex layer part, respectively, and the angle between the line segment PP1 and the y-axis is the air inlet inclination angle α of the air inlet cross section.

4. A multi-layer vector gas port inclination angle parameterized design method according to claim 1, characterized in that: The method for defining the relationship between the air port inclination angle α and the intake port height z coordinate in S7 is: select the z coordinate at the interface between the middle interval of the intake port and the vortex layer as 0, the positive direction of the z axis points to the injector installation position, and define the value range of the vortex layer inclination angle α as 0~α0, that is, the inclination angle at the interface between the middle interval of the intake port and the vortex layer is 0, and the inclination angle at the lowest surface of the vortex layer is α0, and α is a function only about z, that is, α=f(z), where f(z) can be an arbitrary function, and the function f(z) is determined according to the actual demand of the engine for the swirl ratio.

5. The method for parameterized design of multi-layer vector gas port inclination angle according to claim 1, characterized in that: The method for obtaining the DC layer structure of the air inlet in S8 is as follows: in the DC layer air inlet cross section NSS1N1, point N and point S are symmetrical about the y-axis, point S and point S1 are two corresponding points on the AB segment of the DC layer air inlet and the A1B1 segment of the outlet, respectively. Since the DC layer part has no inclination angle, the line segment SS1 is parallel to the y-axis; the length of the straight line segment between point N and point S is the width W of the air inlet, so the x-coordinates of point S and point S1 are both W / 2; the length of line segment OS is the outer diameter of the cylinder sleeve, and the y-coordinate of point S is obtained by the Pythagorean theorem: The length of line segment OS1 is the cylinder diameter D. The y coordinate of point S1 is obtained from the Pythagorean theorem: Then we can get the coordinates of point S (x S ,y S )for Coordinates of point S1 for The z coordinate value range of point S and point S1 is both -h1 to 0.

6. A multi-layer vector gas port inclination angle parameterized design method according to claim 1, characterized in that: In S9, when the air inlet width W, the air inlet thickness t, and the cylinder diameter D are determined, the specific method for solving the relationship between the line segment intercept b and the inclination angle α is: the equation expression of the line segment PP1 is defined as y=kx+b, and the equation expression of the circle where the point P1 is located is defined as x 2 +y 2 =D 2 , combine the two equations, solve the equation system to get the coordinates of the intersection point P1 of the line segment PP1 and the circle where point P1 is located in the first quadrant for The length of the straight line segment between point R and point P is the width W of the air inlet, so the x coordinate of point P is W / 2; the length of line segment OP is the outer diameter of the cylinder liner, and the y coordinate of point P is obtained from the Pythagorean theorem: The slope of the equation of line segment PP1 is k = cotα, and the coordinates of point P are Substituting k=cotα into the equation of line segment PP1 is y=kx+b, and solving the equation yields That is, when the intake port width W, intake port thickness t, and cylinder diameter D are determined, b is a function of only α.

7. A multi-layer vector gas port inclination angle parameterized design method according to claim 1, characterized in that: The method for calculating the specific structure of the air intake in S11 is as follows: through the calculation of S1-S10, it is obtained that the coordinates (x, y) of the air intake inlet AB segment, BC segment and outlet A1B1 segment are only related to the air intake height H, air intake width W, air intake thickness t, and cylinder diameter D of the air intake, and have nothing to do with the z coordinate axis. Therefore, the curves of the AB segment, BC segment and A1B1 segment can be directly drawn in the Creo software; the coordinates (x, y) of the air intake outlet B1C1 segment are functions only about the z coordinate. Using the Excel software, the coordinates of the point P1 corresponding to the z value from 0 to h3 can be obtained. The discrete step length of z can be determined according to specific needs, and then the coordinates of a series of points P1 can be obtained. By importing the coordinate data of point P1 into Creo software, the curve of segment B1C1 can be obtained, and the curves of the inlet and outlet of the air inlet can be obtained, and then the specific structure of the air inlet can be obtained.

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