A piston fire force bank line design method, system and electronic equipment

Abstract

The application discloses a piston fire force bank line design method and system and electronic equipment, which comprises the following steps: S1, performing piston temperature field analysis and piston free expansion analysis, obtaining the thermal expansion amount of the piston fire force bank outer circle surface and the thermal expansion amount y3 of the piston skirt basic diameter; S2, obtaining the compression amount y4 of the skirt main thrust side basic diameter of the piston under the maximum lateral force working condition and the compression amount y5 of the skirt auxiliary thrust side basic diameter of the piston under the minimum lateral force working condition; S3, based on the piston deflection angle, the radial displacement y6 of the fire force bank caused by the rotation of the piston is calculated; S4, the size tolerance chain y7 is determined according to the diameter tolerance band of the fire force bank and the skirt; S5, based on the data obtained from S1 to S4, the design parameters of the piston fire force bank line are calculated. The deformation of the fire force bank in the working state is calculated by the analytical method, and the cold-state line of the piston fire force bank with good performance is efficiently designed while the calculation accuracy is ensured, so that the piston head knocking, cylinder pulling and wear are prevented.

Description

Technical Field

[0001] This invention relates to engine pistons, and more specifically to piston firepower profile design methods, systems, and electronic devices. Background Technology

[0002] Piston profiles include piston fire lander profiles, piston skirt profiles, and pin hole profiles. Piston fire lander profile design is a part of piston profile design. To ensure that the piston fire lander is approximately cylindrical during engine operation and that the piston head does not knock or score, the deformation of the fire lander under operating conditions must be considered, and the cold-state profile of the fire lander must be designed accordingly.

[0003] The piston is one of the parts in the engine with a large heat load. The piston operating temperature varies greatly along the piston axis, with the highest temperature at the top of the fire shore and the lowest temperature at the bottom of the skirt. In addition, the temperature field distribution at the piston head is not uniform, so the axial and circumferential expansion of the fire shore is different after heating.

[0004] Currently, the mainstream design for the piston fire land is that, during cold starts, the diameter reduction at the top of the fire land is greater than that at the bottom, and the diameter reduction at the bottom is greater than that of the basic diameter of the skirt. Furthermore, the out-of-roundness of the fire land along its circumferential deformation is adjusted by designing its ellipticity. Due to the complex boundary conditions of piston operation and the combined effects of thermo-mechanical coupling, calculating the accurate deformation of the fire land under operating conditions using analytical methods is costly and has low accuracy. Currently, most piston fire land profiles are designed based on experience and benchmark databases, and most designs only consider the impact of piston thermal load on the fire land profile design. Summary of the Invention

[0005] The purpose of this invention is to provide a piston fire land profile design method, system, and electronic equipment. The deformation of the fire land in the working state is calculated by analytical method, and while ensuring calculation accuracy, the cold-state profile of the piston fire land with good performance is designed efficiently to prevent piston head knocking, cylinder scoring, and wear.

[0006] The piston firepower shore profile design method of the present invention includes the following steps:

[0007] S1, perform piston temperature field analysis and piston free expansion analysis to obtain the thermal expansion of the piston firepower outer circular surface and the thermal expansion of the piston skirt basic diameter y3;

[0008] S2, obtain the compression amount y4 of the basic diameter of the skirt main thrust side of the piston under the maximum lateral force condition and the compression amount y5 of the basic diameter of the skirt secondary thrust side of the piston under the minimum lateral force condition.

[0009] S3, based on the piston deflection angle, calculate the radial displacement y6 of the fire shore caused by piston rotation;

[0010] S4, determine the dimensional tolerance chain y7 based on the diameter tolerance zone of the fire shore and the skirt;

[0011] S5, based on the data obtained from S1 to S4, calculates the design parameters of the piston fire shore profile.

[0012] Further, step S1 specifically involves: establishing a piston finite element model; performing temperature field analysis and thermal free expansion analysis on the piston finite element model under maximum thermal load conditions; extracting the displacement results after thermal free expansion of the piston finite element model; performing Fourier and inverse Fourier transforms on the displacement results; eliminating rigid displacements; and obtaining the thermal expansion of the outer circular surface of the piston's thrust shore and the thermal expansion of the basic diameter of the piston skirt; the thermal expansion of the uppermost part of the thrust shore's main thrust side is denoted as y. 11 The thermal expansion at the lowest point of the main thrust side of the fire-propelled shore is denoted as y. 21 The thermal expansion at the uppermost part of the fire support shore thrust side is denoted as y. 12 The thermal expansion at the lowest point of the thrust side of the fire-propelled shore engine is denoted as y. 22 .

[0013] Further, step S2 specifically involves: establishing a finite element model including the piston, piston pin, connecting rod, and cylinder liner; determining the connecting rod rotation angle and cylinder pressure value under the conditions of maximum and minimum lateral force of the piston based on the cylinder pressure curve and the parameters of the crank-connecting rod mechanism; rotating the connecting rod through the corresponding angle, with the cylinder pressure acting on the piston top surface through surface pressure; setting a control node in the middle section of the piston pin, which is coupled with the displacement of the internal node in the middle section of the piston pin; the displacement of the control node along the main and auxiliary thrust sides is the piston skirt compression.

[0014] Furthermore, step S3 specifically involves: calculating the radial displacement y6 of the fire station caused by the piston's rotation, based on the piston's geometric dimensions and the angle of rotation around the center of the pin hole. ;

[0015] Where D is the cylinder diameter, e is the piston pin eccentricity distance (the distance between the pin hole axis and the piston axis), and h is the compression height (the height from the center of the pin hole to the top surface of the piston), where the piston top surface refers to the plane where the upper end of the piston rod is located. This is the deflection angle.

[0016] Furthermore, the range of the deflection angle in step S3 is obtained based on the information accumulated in the database.

[0017] Furthermore, the formula for calculating the dimensional tolerance chain y7 in step S4 is:

[0018] y7 = (Upper limit of outer diameter tolerance of fire support - Lower limit of basic diameter tolerance of piston skirt) / 2.

[0019] Furthermore, step S5 specifically involves obtaining the following based on the calculation formula:

[0020] Minimum radius reduction of the fire support on shore Y1=max(y 11 -y3+y4+y6+y7,y 21 -y3+y5+y6+y7),

[0021] Minimum radius reduction at the lower end of the fire support shore Y2=max(y 21 -y3+y4+y6+y7,y 22 -y3+y5+y6+y7),

[0022] Among them, y 11 y represents the thermal expansion at the uppermost part of the main thrust side of the fire-propellant shore engine. 21 y represents the thermal expansion at the lowest point of the main thrust side of the fire-propellant shore engine. 12 y represents the thermal expansion at the uppermost point of the thrust side of the fire support shore unit. 22 This is the thermal expansion at the lowest point of the thrust side of the fire support shore auxiliary;

[0023] Then we have:

[0024] Design value of reduction in radius at the fire station shore end = Minimum reduction in radius at the fire station shore end + Margin setting value;

[0025] Design value of reduction in radius at the lower end of the fire shore = Minimum reduction in radius at the lower end of the fire shore + Margin setting value;

[0026] Firepower shore-top radius = Basic radius value - Design value of firepower shore-top radius reduction;

[0027] The radius of the lower end of the fire shore = the basic value of the radius - the design value of the reduction in the radius of the lower end of the fire shore;

[0028] The basic radius value = basic diameter of piston skirt / 2;

[0029] Once the upper and lower radii of the fire shore are determined, the oblique straight line obtained by connecting them along the height of the fire shore is the fire shore profile.

[0030] A piston fireland profile design system includes: a first acquisition module for performing piston temperature field analysis and piston free expansion analysis to acquire the thermal expansion of the outer circumference of the piston fireland and the thermal expansion of the basic diameter of the piston skirt (y3); a second acquisition module for acquiring the compression of the basic diameter of the skirt on the main thrust side under maximum lateral force conditions (y4) and the compression of the basic diameter of the skirt on the secondary thrust side under minimum lateral force conditions (y5); a third acquisition module for calculating the radial displacement (y6) of the fireland due to piston rotation based on the piston deflection angle; a fourth acquisition module for determining the dimensional tolerance chain (y7) based on the diameter tolerance zones of the fireland and the skirt; and a calculation module for calculating the design parameters of the piston fireland profile based on the data acquired by the first, second, third, and fourth acquisition modules.

[0031] An electronic device includes a memory and a processor, the memory for storing a computer program and the processor for loading and executing the computer program to cause the electronic device to perform the piston firepower shore profile design method as described in this invention.

[0032] This invention employs an analytical method to quantify the contributions of piston thermal load, piston mechanical load, and second-order piston motion to the design of the piston fireland profile. By incorporating the diameter tolerance chain between the fireland and the skirt, and combining accumulated experience and databases, the numerical simulation methods and processes are simplified, enabling the efficient design of high-performance piston fireland profiles and preventing piston head knocking, scoring, and wear. During product development, the piston fireland profile can be further optimized based on the performance parameters of the engine to which the piston will be used, taking into account specific engine performance and piston structure. Attached Figure Description

[0033] Figure 1 This is a flowchart of the piston firepower shore profile design method described in this invention;

[0034] Figure 2 This is a schematic diagram of the piston's fire control profile and skirt profile;

[0035] Figure 3 This is a schematic diagram of the piston's thermal expansion.

[0036] Figure 4 This is a schematic diagram of the piston skirt compression.

[0037] Figure 5 This is a schematic diagram of the piston's deflection angle;

[0038] Figure 6 This is a schematic diagram of the piston structure.

[0039] In the figure, 1—fire shore, 2—fire shore profile, 3—skirt, 4—skirt profile, 5—cold piston, 6—hot piston, 7—piston skirt in free state, 8—piston skirt after compression. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0041] See Figure 1 The piston fire lander profile design method shown includes four influencing factors: fire lander thermal expansion, skirt extrusion deformation, piston deflection angle, and tolerance. (See also...) Figure 2 The diameter reduction at the uppermost end of the fire shore 1 is greater than the diameter reduction at the lowermost end, and the fire shore profile 2 is an inclined segment. The diameter reduction at the lowermost end of the fire shore 1 is greater than the diameter reduction of the basic diameter of the skirt 3, and the skirt profile 4 is elliptical. The design method specifically includes the following steps:

[0042] S1, perform piston temperature field analysis and piston free expansion analysis to obtain the thermal expansion of the piston's outer circular surface and the thermal expansion y3 of the piston skirt's basic diameter. Specifically: establish a piston finite element model, and perform temperature field analysis and thermal free expansion analysis on the piston finite element model under maximum heat load conditions. See [link to relevant documentation]. Figure 3 When the piston is heated, the piston's thrust land 1 and skirt 2 expand outwards, i.e., from the cold piston 5 to the hot piston 6. The displacement results of the piston finite element model after thermal free expansion are extracted, and Fourier and inverse Fourier transforms are performed on the displacement results to eliminate rigid displacements, obtaining the thermal expansion of the outer circular surface of the piston thrust land and the thermal expansion of the basic diameter of the piston skirt; the thermal expansion of the uppermost part of the thrust land on the main thrust side is denoted as y. 11 The thermal expansion at the lowest point of the main thrust side of the fire-propelled shore is denoted as y. 21 The thermal expansion at the uppermost part of the fire support shore thrust side is denoted as y. 12 The thermal expansion at the lowest point of the thrust side of the fire-propelled shore engine is denoted as y. 22 .

[0043] S2, obtain the compression amount y4 of the basic diameter of the skirt on the main thrust side under the maximum lateral force condition and the compression amount y5 of the basic diameter of the skirt on the secondary thrust side under the minimum lateral force condition. See [reference needed]. Figure 4When the piston is subjected to lateral force, the free piston skirt 7 compresses towards the compressed piston skirt 8. Specifically: a finite element model including the piston, piston pin, connecting rod, and cylinder liner is established; based on the cylinder pressure curve and the parameters of the crank-connecting rod mechanism, the rotation angle of the connecting rod and the cylinder pressure value under the conditions of maximum and minimum lateral force of the piston are determined; the connecting rod is rotated through the corresponding angle, and the cylinder pressure acts on the piston top surface through surface pressure; a control node is set in the middle section of the piston pin, and the displacement of this control node is coupled with the displacement of the internal node in the middle section of the piston pin; the displacement of the control node along the main and auxiliary thrust sides is the compression amount of the piston skirt.

[0044] S3, based on the piston deflection angle, calculates the radial displacement y6 of the fire shore caused by piston rotation; the range of values ​​for the deflection angle is obtained based on information accumulated in the database. See also Figure 5 During operation, the piston rotates around the center of the pin hole. The range of the piston deflection angle is -20' to 20', that is, the absolute value of the piston deflection angle is ≤20'.

[0045] The formula for calculating y6 is: ;

[0046] Where D is the cylinder diameter, e is the piston pin eccentricity distance (the distance between the pin hole axis and the piston axis), and h is the compression height (the height from the center of the pin hole to the top surface of the piston), where the piston top surface refers to the plane where the upper end of the piston rod is located. This is the deflection angle.

[0047] S4. Determine the dimensional tolerance chain y7 based on the diameter tolerance zone of the fire shore and the skirt. The formula for calculating the dimensional tolerance chain y7 is: y7 = (upper limit of the outer diameter tolerance of the fire shore - lower limit of the basic diameter tolerance of the piston skirt) / 2.

[0048] S5, based on the data obtained from S1 to S4, calculates the design parameters of the piston fire control profile. Specifically, based on the calculation formula, the following is obtained:

[0049] Minimum radius reduction of the fire support on shore Y1=max(y 11 -y3+y4+y6+y7,y 21 -y3+y5+y6+y7),

[0050] Minimum radius reduction at the lower end of the fire support shore Y2=max(y 21 -y3+y4+y6+y7,y 22 -y3+y5+y6+y7),

[0051] Among them, y 11 y represents the thermal expansion at the uppermost part of the main thrust side of the fire-propellant shore engine. 21 y represents the thermal expansion at the lowest point of the main thrust side of the fire-propellant shore engine. 12 y represents the thermal expansion at the uppermost point of the thrust side of the fire support shore unit.22 This is the thermal expansion at the lowest point of the thrust side of the fire support shore auxiliary;

[0052] Then we have:

[0053] Design value of reduction in radius at the fire station shore end = Minimum reduction in radius at the fire station shore end + Margin setting value;

[0054] Design value of reduction in radius at the lower end of the fire shore = Minimum reduction in radius at the lower end of the fire shore + Margin setting value;

[0055] Firepower shore-top radius = Basic radius value - Design value of firepower shore-top radius reduction;

[0056] The radius of the lower end of the fire shore = the basic value of the radius - the design value of the reduction in the radius of the lower end of the fire shore;

[0057] The basic radius value = basic diameter of piston skirt / 2;

[0058] Once the upper and lower radii of the fire shore are determined, the oblique straight line obtained by connecting them along the height of the fire shore is the fire shore profile.

[0059] See Figure 6 The outer diameter of the skirt, h1 below the horizontal center of the pin hole, is taken as the basic diameter of the piston skirt, and the basic diameter of the piston skirt, D0, is... mm, the minimum radius reduction of the fire station on shore end obtained by the design method described in this invention is 0.72 mm, and the margin setting value is ±0.025. Then the radius of the fire station on shore end D3 = 78 - 0.72 ± 0.025 = 77.28 ± 0.025 mm.

[0060] The minimum radius reduction at the lower end of the fire shore is 0.62 mm, and the allowance is set at ±0.025. Therefore, the radius at the upper end of the fire shore, D4, is 78 - 0.62 ± 0.025 = 77.38 ± 0.025 mm.

[0061] The plane containing the first diameter D1 of the piston skirt coincides with the pin hole. The distance between the plane containing the first diameter D1 of the piston skirt and the plane containing the basic diameter of the piston skirt is h1. The first diameter D1 = D0 - 0.024 ± 0.004.

[0062] The distance between the plane containing the second diameter D2 of the piston skirt and the plane containing the basic diameter of the piston skirt is h2, and the second diameter D2 = D0 - 0.138 ± 0.004.

[0063] The distance between the plane containing the basic diameter of the piston skirt and the piston top surface is h3, where h1 = 10mm, h2 = 18mm, and h3 = 37.5mm. The compression height h = h3 - h1 = 37.5 - 10 = 27.5mm, and the piston pin eccentricity distance... =0.06±0.1

[0064] A piston fireland profile design system includes: a first acquisition module for performing piston temperature field analysis and piston free expansion analysis to acquire the thermal expansion of the outer circumference of the piston fireland and the thermal expansion of the basic diameter of the piston skirt (y3); a second acquisition module for acquiring the compression of the basic diameter of the skirt on the main thrust side under maximum lateral force conditions (y4) and the compression of the basic diameter of the skirt on the secondary thrust side under minimum lateral force conditions (y5); a third acquisition module for calculating the radial displacement (y6) of the fireland due to piston rotation based on the piston deflection angle; a fourth acquisition module for determining the dimensional tolerance chain (y7) based on the diameter tolerance zones of the fireland and the skirt; and a calculation module for calculating the design parameters of the piston fireland profile based on the data acquired by the first, second, third, and fourth acquisition modules.

[0065] An electronic device includes a memory and a processor, the memory for storing a computer program and the processor for loading and executing the computer program to cause the electronic device to perform the piston firepower shore profile design method as described in this invention.

[0066] 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, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for designing piston firepower shore profiles, characterized in that, Includes the following steps: S1, perform piston temperature field analysis and piston free expansion analysis to obtain the thermal expansion of the piston firepower outer circular surface and the thermal expansion of the piston skirt basic diameter y3; S2, obtain the compression amount y4 of the basic diameter of the skirt main thrust side of the piston under the maximum lateral force condition and the compression amount y5 of the basic diameter of the skirt secondary thrust side of the piston under the minimum lateral force condition. S3, based on the piston deflection angle, calculate the radial displacement y6 of the fire shore caused by piston rotation; S4, determine the dimensional tolerance chain y7 based on the diameter tolerance zone of the fire shore and the skirt; S5, based on the data obtained from S1 to S4, calculates the design parameters of the piston fire shore profile.

2. The piston firepower shore profile design method according to claim 1, characterized in that, The specific steps of step S1 are as follows: establish a piston finite element model, perform temperature field analysis and thermal free expansion analysis on the piston finite element model under the maximum heat load condition, extract the displacement results after the piston finite element model undergoes thermal free expansion, perform Fourier and inverse Fourier transformations on the displacement results, eliminate rigid displacements, and obtain the thermal expansion of the outer circular surface of the piston fire shore and the thermal expansion of the basic diameter of the piston skirt. The thermal expansion at the uppermost part of the main thrust side of the fire-powered shore engine is denoted as y. 11 The thermal expansion at the lowest point of the main thrust side of the fire-propelled shore is denoted as y. 21 The thermal expansion at the uppermost part of the fire support shore thrust side is denoted as y. 12 The thermal expansion at the lowest point of the thrust side of the fire-propelled shore engine is denoted as y. 22 .

3. The piston firepower shore profile design method according to claim 1 or 2, characterized in that, Step S2 specifically involves: establishing a finite element model including the piston, piston pin, connecting rod, and cylinder liner; determining the connecting rod rotation angle and cylinder pressure value under the conditions of maximum and minimum lateral force of the piston based on the cylinder pressure curve and the parameters of the crank-connecting rod mechanism; rotating the connecting rod through the corresponding angle, with the cylinder pressure acting on the piston top surface through surface pressure; setting a control node in the middle section of the piston pin, which is coupled with the displacement of the internal node in the middle section of the piston pin; the displacement of the control node along the main and auxiliary thrust sides is the piston skirt compression.

4. The piston firepower shore profile design method according to claim 1 or 2, characterized in that, Step S3 specifically involves: calculating the radial displacement y6 of the firepower shore caused by the piston rotation based on the piston's geometric dimensions and the angle of rotation around the center of the pin hole. ; Where D is the cylinder bore, e is the piston pin offset distance, and h is the compression height. This is the deflection angle.

5. The piston firepower shore profile design method according to claim 1 or 2, characterized in that: The range of values ​​for the deflection angle in step S3 is obtained based on the information accumulated in the database.

6. The piston firepower shore profile design method according to claim 1 or 2, characterized in that, The formula for calculating the dimensional tolerance chain y7 in step S4 is: y7 = (upper limit of the outer diameter tolerance of the fire station - lower limit of the basic diameter tolerance of the piston skirt) / 2.

7. The piston firepower shore profile design method according to claim 1 or 2, characterized in that, Specifically, step S5 involves obtaining the following based on the calculation formula: Minimum radius reduction of the fire support on shore Y1=max(y 11 -y3+y4+y6+y7,y 21 -y3+y5+y6+y7), Minimum radius reduction at the lower end of the fire support shore Y2=max(y 21 -y3+y4+y6+y7,y 22 -y3+y5+y6+y7), Among them, y 11 y represents the thermal expansion at the uppermost part of the main thrust side of the fire-propellant shore engine. 21 y represents the thermal expansion at the lowest point of the main thrust side of the fire-propellant shore engine. 12 y represents the thermal expansion at the uppermost point of the thrust side of the fire support shore unit. 22 This is the thermal expansion at the lowest point of the thrust side of the fire support shore auxiliary; Then we have: Design value of reduction in radius at the fire station shore end = Minimum reduction in radius at the fire station shore end + Margin setting value; Design value of reduction in radius at the lower end of the fire shore = Minimum reduction in radius at the lower end of the fire shore + Margin setting value; Firepower shore-top radius = Basic radius value - Design value of firepower shore-top radius reduction; The radius of the lower end of the fire shore = the basic value of the radius - the design value of the reduction in the radius of the lower end of the fire shore; The basic radius value = basic diameter of piston skirt / 2; Once the upper and lower radii of the fire shore are determined, the oblique straight line obtained by connecting them along the height of the fire shore is the fire shore profile.

8. A piston-fire shore profile design system, characterized in that, include: The first acquisition module is used to perform piston temperature field analysis and piston free expansion analysis to obtain the thermal expansion of the outer circular surface of the piston fire shore and the thermal expansion of the basic diameter of the piston skirt, y3. The second acquisition module is used to acquire the compression amount y4 of the basic diameter of the skirt main thrust side of the piston under the maximum lateral force condition and the compression amount y5 of the basic diameter of the skirt secondary thrust side of the piston under the minimum lateral force condition. The third acquisition module calculates and acquires the radial displacement y6 of the fire shore caused by the piston rotation based on the piston deflection angle. The fourth acquisition module determines the dimensional tolerance chain y7 based on the diameter tolerance zone of the fire shore and the skirt. The calculation module calculates the design parameters of the piston fire shore profile based on the data obtained by the first acquisition module, the second acquisition module, the third acquisition module, and the fourth acquisition module.

9. An electronic device, characterized in that: It includes a memory and a processor, the memory being used to store a computer program, and the processor being used to load and execute the computer program to cause the electronic device to perform the piston firepower shore profile design method as described in any one of claims 1 to 7.

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