Design method of engine cylinder and engine cylinder

Abstract

According to the design method of the engine cylinder, the engine cylinder comprises a cylinder body and a cylinder cover, and the cylinder cover is provided with an inlet valve seat ring; a plane which passes through the central axis of the intake valve seat ring and is parallel to the XZ plane is a second plane, and the second plane is provided with a second rotating center; the connecting line of the first rotation center and the second rotation center is a rotation axis, and the projection axis of the projection of the rotation axis on the YZ plane; the included angle between the projection axis and the Y axis is a parameter included angle; the ratio of the Z-axis coordinate of the first rotating center to the inner diameter of the engine cylinder is a parameter ratio; the design method comprises the steps that size parameters of an engine cylinder are adjusted, and a CFD model is used for conducting single-time simulation calculation on the engine cylinder within the range that the crank angle ranges from 360 degrees to 0 degree; obtaining a parameter included angle and a parameter ratio in a single simulation calculation process; whether the parameter included angle is within a set included angle range or not and whether the parameter ratio is within a set ratio range or not are judged, if yes, single-time simulation calculation is stopped, and the single-time simulation calculation is stopped at a set rotating angle P, and Plt is smaller than or equal to-160 degrees; 0 DEG.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to a design method for an engine cylinder and an engine cylinder. Background Art

[0002] Small-scale strengthening technology can improve the engine's output power and fuel economy, and help reduce pumping losses.

[0003] However, as the compression ratio and load increase, the mixture at the end of the cylinder is prone to spontaneous combustion, and the tendency of knock increases. The occurrence of knock easily causes damage to the internal parts of the engine, and also affects the power output of the engine, limiting the further improvement of the engine efficiency. In view of this, the existing technology generally suppresses the knock under low-speed and high-load conditions of the engine by increasing the tumble ratio inside the cylinder.

[0004] To this end, it is necessary to design an engine cylinder with a high tumble ratio. In the prior art, the design of the engine cylinder is mainly based on the computational fluid dynamics (CFD) simulation to calculate the operating conditions inside the cylinder. Generally speaking, the CFD simulation calculation is calculated from one top dead center (the crankshaft angle is set to -360°) to another top dead center (the crankshaft angle is set to 0°) to simulate the operating conditions inside the cylinder within a complete cycle. In this way, the simulation calculation time will be relatively long, which is not conducive to rapid cylinder design.

[0005] Therefore, how to provide a solution to overcome or alleviate the above-mentioned defects is still a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0006] The purpose of the present invention is to provide a design method for an engine cylinder and an engine cylinder, wherein the design method can complete the design of the engine cylinder more quickly.

[0007] In order to solve the above technical problems, the present invention provides a design method for an engine cylinder, wherein the engine cylinder comprises a cylinder block and a cylinder head, wherein the cylinder head is provided with an intake valve seat ring; an XYZ coordinate system is defined, wherein the XYZ coordinate system comprises an X-axis, a Y-axis and a Z-axis, wherein the X-axis and the Y-axis constitute an XY plane, wherein the X-axis and the Z-axis constitute an XZ plane, and wherein the Y-axis and the Z-axis constitute a YZ plane; wherein the lower surface of the cylinder head is located in the XY plane; a plane passing through the central axis of the engine cylinder and parallel to the XZ plane is a first plane, wherein the first plane has a first rotation center; a plane passing through the central axis of the intake valve seat ring and parallel to the XZ plane is a second plane, wherein the second plane has a second rotation center; a line connecting the first rotation center and the second rotation center is a rotation axis, wherein the projection axis of the rotation axis on the YZ plane is a projection axis; an angle between the projection axis and the Y-axis is a parameter angle; a ratio of the Z-axis coordinate of the first rotation center to the inner diameter of the engine cylinder is a parameter ratio;

[0008] The design method comprises:

[0009] Adjusting the size parameters of the engine cylinder, and using a CFD model to perform a single simulation calculation on the engine cylinder within a crankshaft angle range of -360° to 0°;

[0010] Obtaining the parameter angle and the parameter ratio in the single simulation calculation process;

[0011] Determine whether the parameter angle is within the set angle range and whether the parameter ratio is within the set ratio range. If so, terminate the single simulation calculation. The single simulation calculation terminates at the set rotation angle P, -160°≤P<0°.

[0012] By adopting the above scheme, by introducing the parameter angle and the parameter ratio, and judging whether the parameter angle is within the set angle range and whether the parameter ratio is within the set ratio range, a single simulation calculation can be terminated at the set rotation angle P, -160°≤P<0°, that is, the single simulation calculation can be terminated before 0°. In this way, the time spent on a single simulation calculation can be reduced, and accordingly, the time spent on the design method provided by the embodiment of the present invention can also be greatly reduced, so that an engine cylinder with a high tumble ratio can be designed more quickly.

[0013] Optionally, the set angle range is [5°, 10°], and the set ratio range is [-0.45, -0.35].

[0014] Optionally, the set rotation angle P has a value range of [-90°, -60°].

[0015] Optionally, the cylinder head is also configured with an exhaust valve seat ring and a spark plug, the number of the intake valve seat ring and the exhaust valve seat ring are two, the intake valve seat ring and the exhaust valve seat ring are respectively located on both sides of the YZ plane, the two intake valve seat rings are respectively located on both sides of the XZ plane, and the two exhaust valve seat rings are respectively located on both sides of the XZ plane; the spacing between the intake valve seat ring and the exhaust valve seat ring located on the same side of the XZ plane is c, the spacing between the two intake valve seat rings is d, the spacing between the two exhaust valve seat rings is e, the spacing between the intake valve seat ring and the spark plug is f, and the spacing between the exhaust valve seat ring and the spark plug is g; the size parameters include c, d, e, f and g.

[0016] Optionally, the design method also includes: using the CFD model to perform the single simulation calculations a set number of times, and obtaining the maximum tumble ratio under each of the single simulation calculations; comparing the maximum tumble ratios, and taking the maximum value therein as the optimal tumble ratio, and at the same time outputting the optimal dimensional parameters corresponding to the optimal tumble ratio.

[0017] Optionally, the optimal size parameters are: e=x, c=0.548x, d=0.488x, f=0.533x, g=0.595x, and x is between 0.75 and 1.3.

[0018] Optionally, the distance between the centers of the two intake valve seat rings is a, the distance between the centers of the two outlet valve seat rings is b, and the size parameters also include a and b.

[0019] Optionally, there are two intake valve seat rings, and the two intake valve seat rings are respectively located on both sides of the XZ plane. There are two second rotation centers, thereby forming two projection axes, and the maximum value of the angles between the two projection axes and the Y axis is the parameter angle.

[0020] The present invention also provides an engine cylinder, wherein the engine cylinder is designed by the above-mentioned engine cylinder design method.

[0021] Optionally, the cylinder head is further configured with an exhaust valve seat ring and a spark plug, the number of the intake valve seat ring and the exhaust valve seat ring are both two, the intake valve seat ring and the exhaust valve seat ring are respectively located on both sides of the YZ plane, the two intake valve seat rings are respectively located on both sides of the XZ plane, and the two exhaust valve seat rings are respectively located on both sides of the XZ plane; the distance between the centers of the two intake valve seat rings is a, the distance between the centers of the two exhaust valve seat rings is b, and the two valve seat rings located on the same side of the XZ plane are respectively located on both sides of the XZ plane. The spacing between the intake valve seat ring and the outlet valve seat ring is c, the spacing between the two intake valve seat rings is d, the spacing between the two outlet valve seat rings is e, the spacing between the intake valve seat ring and the spark plug is f, and the spacing between the outlet valve seat ring and the spark plug is g; the dimensional parameters include a, b, c, d, e, f, g; among the dimensional parameters: e=x, c=0.548x, d=0.488x, f=0.533x, g=0.595x; x is between 0.75 and 1.3. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic flow chart of the engine cylinder design method provided by the present invention;

[0023] Figure 2 It is a structural schematic diagram of a cylinder head of an engine cylinder;

[0024] Figure 3 A simulation diagram of a cylinder head and a first plane and a second plane;

[0025] Figure 4 is a simulated diagram of a first rotation center of a first plane;

[0026] Figure 5 A top view of a cylinder head of an engine cylinder;

[0027] Figure 6 It is a structural schematic diagram of the projection axis of a rotation axis on the YZ plane;

[0028] Figure 7 It is a structural schematic diagram of another projection axis of the rotation axis on the YZ plane;

[0029] Figure 8 is the relationship diagram between parameter angle and tumble ratio;

[0030] Fig. 9 is the relationship diagram between parameter ratio and tumble ratio;

[0031] Fig.10 It is a structural schematic diagram of tumble ratio and crankshaft angle under different size parameters.

[0032] The following are the descriptions of the reference numerals:

[0033] 1 cylinder head, 11 intake valve seat, 12 exhaust valve seat, 13 spark plug;

[0034] 100 first plane, 110 first rotation center;

[0035] 200 second plane, 210 second rotation center. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0037] In the embodiments of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0038] In the description of the embodiments of the present invention, the terms "comprises", "includes" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0039] Embodiment 1

[0040] Please refer to Figure 1-Figure 10 , Figure 1 It is a schematic flow chart of the design method of the engine cylinder provided by the present invention, Figure 2 The schematic diagram of the structure of the cylinder head of the engine cylinder is shown in FIG. Figure 3 is a simulation diagram of the cylinder head and the first plane and the second plane, Figure 4 is a simulation diagram of the first rotation center of the first plane, Figure 5 A top view of the cylinder head of the engine cylinder. Figure 6 It is a structural schematic diagram of the projection axis of a rotation axis on the YZ plane. Figure 7 It is a structural schematic diagram of another projection axis of the rotation axis on the YZ plane. Figure 8 is the relationship diagram between parameter angle and tumble ratio, Fig. 9 is the relationship diagram between parameter ratio and tumble ratio, Fig.10 It is a structural schematic diagram of tumble ratio and crankshaft angle under different size parameters.

[0041] The present invention provides a design method for an engine cylinder, combining Figure 2-Figure 5 The engine cylinder includes a cylinder block (not shown in the figure) and a cylinder head 1, and the cylinder head 1 is provided with an intake valve seat ring 11, an outlet valve seat ring 12 and a spark plug 13.

[0042] For ease of description, an XYZ coordinate system can be defined. The XYZ coordinate system includes an X-axis, a Y-axis, and a Z-axis, wherein the X-axis and the Y-axis constitute an XY plane, the X-axis and the Z-axis constitute an XZ plane, the Y-axis and the Z-axis constitute a YZ plane, the lower surface of the cylinder head 1 is located in the XY plane, and the internal space of the cylinder body is located on the lower side of the XY plane as a whole, that is, on the negative half axis of the Z axis.

[0043] Combination Figure 3 , a plane passing through the central axis of the engine cylinder and parallel to the XZ plane is defined as a first plane 100, and the first plane 100 has a first rotation center 110; the first rotation center 110 here is the flow velocity rotation center, specifically refers to the center point of an area on the first plane 100, away from the inner wall of the cylinder body, and where the air flow velocity is less than 5m / s. Then, a plane passing through the central axis of the intake valve seat ring 11 and parallel to the XZ plane is defined as a second plane 200, and the second plane 200 has a second rotation center 210; the second rotation center 210 here is also the flow velocity rotation center, specifically refers to the center point of an area on the second plane 200, away from the inner wall of the cylinder body, and where the air flow velocity is less than 5m / s.

[0044] The line connecting the first rotation center 110 and the second rotation center 210 is the rotation axis, which is a spatial figure in the XYZ coordinate system. Figure 6 and Figure 7 , define the projection of the rotation axis on the YZ plane as the projection axis.

[0045] The angle between the projection axis and the Y axis is the parameter angle α; Figure 6 As shown, when the second rotation center 210 is lower than the first rotation center 110, the parameter angle α is a negative value, and when the second rotation center 210 is higher than the first rotation center 110, the parameter angle α is a positive value. The ratio of the Z-axis coordinate of the first rotation center 110 and the inner diameter of the engine cylinder is the parameter ratio; the larger the parameter ratio, the closer the tumble axis is to the intake duct, and the smaller the parameter ratio, the farther the tumble axis is from the intake duct. In the embodiment of the present invention, the two parameters of the parameter angle α and the parameter ratio are introduced to perform computational fluid dynamics (CFD) simulation calculations.

[0046] Specifically, Figure 1As shown, the design method provided by the embodiment of the present invention includes: step S1, adjusting the size parameters of the engine cylinder, and using the CFD model to perform a single simulation calculation on the engine cylinder within the crankshaft angle range of -360° to 0°; step S2, obtaining the parameter angle and parameter ratio in the single simulation calculation process; step S3, judging whether the parameter angle is within the set angle range, and whether the parameter ratio is within the set ratio range, if so, terminating the single simulation calculation, and the single simulation calculation is terminated at the set angle P, -160°≤P<0°.

[0047] By adopting the above scheme, by introducing the parameter angle and the parameter ratio, and judging whether the parameter angle is within the set angle range and whether the parameter ratio is within the set ratio range, a single simulation calculation can be terminated at the set rotation angle P, -160°≤P<0°, that is, the single simulation calculation can be terminated before 0°. In this way, the time spent on a single simulation calculation can be reduced, and accordingly, the time spent on the design method provided by the embodiment of the present invention can also be greatly reduced, so that an engine cylinder with a high tumble ratio can be designed more quickly.

[0048] Combination Fig.10 In the process of the crankshaft angle changing from -360° to -160°, the tumble ratio can already present a complete peak shape, and, in the process after -160°, the piston compresses the gas in the cylinder upward, causing the tumble ratio curves in the cylinder corresponding to different cylinder designs to cross, that is, the maximum tumble ratio under the size parameters obtained before -160° may decay too quickly after -160°, and the tumble ratio is too low near 0°. Therefore, setting the set angle P between [-160°, 0°) as a key interval for judging the decay speed of the tumble ratio is also a good stop point, which can not only obtain the key information of the simulation calculation, but also greatly reduce the simulation calculation time.

[0049] Furthermore, in an embodiment of the present invention, the value range of the setting angle P can be [-90°, -60°]. In this way, the value interval of the parameter angle and the parameter ratio can be smaller, which is more conducive to accurately positioning the termination point of a single simulation calculation.

[0050] Combination Figure 8 and Fig. 9 , the setting angle range can be [5°, 10°], and the setting ratio range can be [-0.45, -0.35]. At this time, the scattered points in the figure are relatively concentrated, and the tumble ratios under the setting angle range and the setting ratio range can be basically consistent, which can better match the tumble ratio corresponding to the setting angle P.

[0051] In an embodiment of the present invention, the number of the intake valve seat rings 11 and the outlet valve seat rings 12 can be two, the intake valve seat rings 11 and the outlet valve seat rings 12 can be respectively located on both sides of the YZ plane, the two intake valve seat rings 11 can be respectively located on both sides of the XZ plane, and the two outlet valve seat rings 12 can be respectively located on both sides of the XZ plane.

[0052] Combination Figure 2 , the distance between the intake valve seat ring 11 and the outlet valve seat ring 12 located on the same side of the XZ plane can be recorded as c, the distance between the two intake valve seat rings 11 can be recorded as d, the distance between the two outlet valve seat rings 12 can be recorded as e, the distance between the intake valve seat ring 11 and the spark plug 13 can be recorded as f, and the distance between the outlet valve seat ring 12 and the spark plug 13 can be recorded as g.

[0053] The dimensional parameters of the engine cylinder may include c, d, e, f and g as mentioned above.

[0054] Combination Figure 1 The design method provided by the present invention may also include: step S5, using the CFD model to perform a set number of single simulation calculations, and obtaining the maximum tumble ratio under each single simulation calculation; step S6, comparing the maximum tumble ratios, and taking the maximum value therein as the optimal tumble ratio, and outputting the optimal size parameters corresponding to the optimal tumble ratio.

[0055] Here, the embodiment of the present invention does not limit the optimal size parameters. In practical applications, those skilled in the art can determine them based on the results of simulation calculations. For example, the optimal size parameters may be: e=x, c=0.548x, d=0.488x, f=0.533x, g=0.595x, where x is between 0.75 and 1.3.

[0056] In addition to the above-mentioned c, d, e, f, and g, the distance between the centers of the two intake valve seat rings 11 is a, the distance between the centers of the two outlet valve seat rings 12 is b, and the above-mentioned dimensional parameters may also include a and b.

[0057] When the number of intake valve seat rings 11 is two, there may be two second planes 200, and accordingly, there may be two second rotation centers 210, thereby forming two projection axes, such as Figure 6 and Figure 7 As shown, the angles between the two projection axes and the Y axis are α1 and α2 respectively. If α1 and α2 are equal, then either of them can be taken as the parameter angle. If α1 and α2 are not equal, then the maximum value of α1 and α2 can be taken as the parameter angle.

[0058] Embodiment 2

[0059] The present invention also provides an engine cylinder, which can be specifically designed by the design methods involved in each implementation manner in the first embodiment.

[0060] Specifically, the cylinder head 1 of the engine cylinder can be configured with an intake valve seat ring 11, an exhaust valve seat ring 12 and a spark plug 13. The number of the intake valve seat ring 11 and the exhaust valve seat ring 12 can be two. The intake valve seat ring 11 and the exhaust valve seat ring 12 can be located on both sides of the YZ plane respectively. The two intake valve seat rings 11 can be located on both sides of the XZ plane respectively, and the two exhaust valve seat rings 12 can be located on both sides of the XZ plane respectively.

[0061] The distance between the centers of the two intake valve seat rings 11 can be recorded as a, the distance between the centers of the two outlet valve seat rings 12 can be recorded as b, the distance between the intake valve seat ring 11 and the outlet valve seat ring 12 located on the same side of the XZ plane can be recorded as c, the distance between the two intake valve seat rings 11 can be recorded as d, the distance between the two outlet valve seat rings 12 can be recorded as e, the distance between the intake valve seat ring 11 and the spark plug 13 can be recorded as f, and the distance between the outlet valve seat ring 12 and the spark plug 13 can be recorded as g.

[0062] The above-mentioned size parameters may include a, b, c, d, e, f, and g.

[0063] Moreover, among the dimensional parameters: e=x, c=0.548x, d=0.488x, f=0.533x, g=0.595x; x is between 0.75 and 1.3. In this way, the designed engine cylinder can have a relatively high tumble ratio.

[0064] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for designing an engine cylinder, characterized in that: The engine cylinder comprises a cylinder block and a cylinder head, wherein the cylinder head is provided with an intake valve seat ring; Define an XYZ coordinate system, the XYZ coordinate system includes an X-axis, a Y-axis and a Z-axis, the X-axis and the Y-axis constitute an XY plane, the X-axis and the Z-axis constitute an XZ plane, and the Y-axis and the Z-axis constitute a YZ plane; wherein the lower surface of the cylinder head is located in the XY plane; A plane passing through the central axis of the engine cylinder and parallel to the XZ plane is a first plane, and the first plane has a first rotation center; a plane passing through the central axis of the intake valve seat ring and parallel to the XZ plane is a second plane, and the second plane has a second rotation center; a line connecting the first rotation center and the second rotation center is a rotation axis, and the projection axis of the rotation axis on the YZ plane is a projection axis; an angle between the projection axis and the Y axis is a parameter angle; a ratio of the Z axis coordinate of the first rotation center to the inner diameter of the engine cylinder is a parameter ratio; The design method comprises: Adjusting the size parameters of the engine cylinder, and using a CFD model to perform a single simulation calculation on the engine cylinder within a crankshaft angle range of -360° to 0°; Obtaining the parameter angle and the parameter ratio in the single simulation calculation process; Determine whether the parameter angle is within the set angle range and whether the parameter ratio is within the set ratio range. If so, terminate the single simulation calculation. The single simulation calculation terminates at the set rotation angle P, -160°≤P<0°.

2. The method for designing an engine cylinder according to claim 1, characterized in that: The set angle range is [5°, 10°], and the set ratio range is [-0.45, -0.35].

3. The method for designing an engine cylinder according to claim 1, characterized in that: The value range of the set rotation angle P is [-90°, -60°].

4. The method for designing an engine cylinder according to any one of claims 1 to 3, characterized in that: The cylinder head is also equipped with an outlet valve seat ring and a spark plug. The number of the inlet valve seat ring and the outlet valve seat ring are both two, and the inlet valve seat ring and the outlet valve seat ring are respectively located on both sides of the YZ plane, the two inlet valve seat rings are respectively located on both sides of the XZ plane, and the two outlet valve seat rings are respectively located on both sides of the XZ plane; The distance between the intake valve seat ring and the outlet valve seat ring located on the same side of the XZ plane is c, the distance between the two intake valve seat rings is d, the distance between the two outlet valve seat rings is e, the distance between the intake valve seat ring and the spark plug is f, and the distance between the outlet valve seat ring and the spark plug is g; The dimensional parameters include c, d, e, f and g.

5. The method for designing an engine cylinder according to claim 4, characterized in that: The design method further comprises: Using the CFD model to perform the single simulation calculations a set number of times, and obtaining the maximum tumble ratio under each of the single simulation calculations; The maximum tumble ratios are compared, and the maximum value thereof is taken as the optimal tumble ratio, and the optimal size parameter corresponding to the optimal tumble ratio is outputted at the same time.

6. The method for designing an engine cylinder according to claim 5, characterized in that: The optimal size parameters are: e=x, c=0.548x, d=0.488x, f=0.533x, g=0.595x, and x is between 0.75 and 1.

3.

7. The method for designing an engine cylinder according to claim 4, characterized in that: The distance between the centers of the two intake valve seat rings is a, the distance between the centers of the two outlet valve seat rings is b, and the size parameters also include a and b.

8. The method for designing an engine cylinder according to any one of claims 1 to 3, characterized in that: There are two intake valve seat rings, and the two intake valve seat rings are respectively located on both sides of the XZ plane. There are two second rotation centers, thereby forming two projection axes, and the maximum value of the angles between the two projection axes and the Y axis is the parameter angle.

9. An engine cylinder, characterized in that: The engine cylinder is designed by the engine cylinder design method according to any one of claims 1-8.

10. The engine cylinder according to claim 9, characterized in that: The cylinder head is also equipped with an outlet valve seat ring and a spark plug. The number of the inlet valve seat ring and the outlet valve seat ring are both two, and the inlet valve seat ring and the outlet valve seat ring are respectively located on both sides of the YZ plane, the two inlet valve seat rings are respectively located on both sides of the XZ plane, and the two outlet valve seat rings are respectively located on both sides of the XZ plane; The distance between the centers of the two intake valve seat rings is a, the distance between the centers of the two outlet valve seat rings is b, the distance between the intake valve seat ring and the outlet valve seat ring on the same side of the XZ plane is c, the distance between the two intake valve seat rings is d, the distance between the two outlet valve seat rings is e, the distance between the intake valve seat ring and the spark plug is f, and the distance between the outlet valve seat ring and the spark plug is g; The size parameters include a, b, c, d, e, f, and g; Among the dimensional parameters: e = x, c = 0.548x, d = 0.488x, f = 0.533x, g = 0.595x; x is between 0.75 and 1.3.

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