CN118133702A - Method for designing cylinder hole of engine - Google Patents

Method for designing cylinder hole of engine Download PDF

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Publication number
CN118133702A
CN118133702A CN202311833970.5A CN202311833970A CN118133702A CN 118133702 A CN118133702 A CN 118133702A CN 202311833970 A CN202311833970 A CN 202311833970A CN 118133702 A CN118133702 A CN 118133702A
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cylinder
kinetic energy
knocking
friction work
piston
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张俊红
王宁
戴胡伟
林杰威
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Tianjin University
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Tianjin University
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G06F30/28—Design optimisation, verification or simulation using fluid dynamics, e.g. using Navier-Stokes equations or computational fluid dynamics [CFD]
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/08—Thermal analysis or thermal optimisation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Fluid Mechanics (AREA)
  • Mathematical Analysis (AREA)
  • Mathematical Optimization (AREA)
  • Computing Systems (AREA)
  • Pure & Applied Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Evolutionary Computation (AREA)
  • Geometry (AREA)
  • General Engineering & Computer Science (AREA)
  • Algebra (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)

Abstract

The invention discloses a design method of a cylinder hole of an engine, wherein the cylinder hole comprises a cylindrical surface and a conical surface which are connected in sequence, and a plurality of micro grooves are formed in the inner surface of a top dead center area of the cylindrical surface; the design method comprises the following steps: the method comprises the steps of performing simulation experiments by utilizing fluid dynamics simulation software and performing experiments on an engine bench to obtain a dynamics model representing the corresponding relation between shape parameters, friction work and knocking kinetic energy of a cylinder hole; according to the dynamics model, multiple groups of first data used for representing the corresponding relation between the structures of different micro-grooves and the peaks of friction work and knocking kinetic energy are obtained, and multiple groups of second data used for representing the corresponding relation between the molded line parameters of different cylindrical surfaces and conical surfaces and the peaks of friction work and knocking kinetic energy are obtained; and obtaining the profile parameters of the micro groove structure, the cylindrical surface and the conical surface corresponding to the minimum value of the friction work and the minimum value of the peak value of the knocking kinetic energy in the plurality of groups of first data and the plurality of groups of second data.

Description

Method for designing cylinder hole of engine
Technical Field
At least one embodiment of the invention relates to the technical field of engine design, in particular to a method for designing a cylinder hole of an engine.
Background
With the increasing of the combustion enhancement degree of the diesel engine, the thermal load and the mechanical load born by the cylinder hole in the working process of the diesel engine are increased, and the deformation degree of the cylinder hole of the engine under the action of the thermal load and the mechanical load is also easy to be increased. Studies have shown that an increased degree of irregular deformation of the cylinder liner results in an increased friction loss between the piston rings and the piston, respectively, and the inner wall of the cylinder bore. The friction loss generated in the working process of the piston accounts for 50% -68% of the total friction loss of the engine, and when the friction loss of the engine is increased by 10%, the fuel consumption is increased by 3% -5%, and the dynamic property is correspondingly reduced. In addition, irregular deformation of the cylinder bore may cause an increase in the inter-cylinder gap, thereby causing an increase in piston knocking noise. Therefore, the friction work of two pairs of friction pairs of the piston and the inner wall of the cylinder hole of the cylinder and the piston ring and the inner wall of the cylinder hole of the cylinder and the peak value of knocking kinetic energy generated by the fact that the piston knocks the inner wall of the cylinder hole of the cylinder are reduced, and the method has important significance for improving the economy of the diesel engine and reducing noise pollution.
In the prior art, one of the three modes of optimizing a piston skirt profile, arranging a tiny pit in the inner wall of a cylinder hole and optimizing the cylinder hole profile is mainly adopted, so that friction loss between a piston and a piston ring and the inner wall of the cylinder hole and knocking kinetic energy of the piston knocking the inner wall of the cylinder hole are reduced. However, by adopting a mode of optimizing the profile of the skirt portion of the piston, the friction loss between the piston and the friction pair at the inner wall of the cylinder hole can be reduced, and the friction loss between the piston ring and the friction pair at the inner wall of the cylinder hole is not improved. Further, by adopting a mode of optimizing the molded line of the cylinder hole, the friction loss between the piston and the inner wall of the cylinder hole and between the piston ring and the inner wall of the cylinder hole is improved to a certain extent, however, the negative influence of the increase of knocking noise of the piston knocking the cylinder hole caused by overlarge gaps between the piston ring and the inner wall of the cylinder hole and between the piston and the inner wall of the cylinder hole is ignored. Furthermore, by arranging the micro pits on the inner wall of the cylinder hole, the friction loss between the piston and the inner wall of the cylinder hole and between the piston ring and the inner wall of the cylinder hole is improved, and the gap between the piston ring and the inner wall of the cylinder hole and between the piston and the inner wall of the cylinder hole is not increased, but the knocking kinetic energy generated when the piston knocks the inner wall of the cylinder hole is not improved.
Thus, the conventional method for designing a cylinder bore of an engine in which only a small pit is provided in the inner wall of the cylinder bore cannot simultaneously reduce friction loss between the piston and the piston ring and the inner wall of the cylinder bore, and knocking kinetic energy generated when the piston knocks against the inner wall of the cylinder bore.
Disclosure of Invention
In view of the above, the present invention provides a method for designing a cylinder bore of an engine, so as to reduce friction losses between a piston and a piston ring, respectively, and an inner wall of the cylinder bore of the cylinder, and reduce knocking kinetic energy generated when the piston knocks the inner wall of the cylinder bore of the cylinder.
According to the embodiment of the invention, a design method of a cylinder hole of an engine is provided, the engine comprises a piston, a piston ring and a cylinder, the cylinder hole of the cylinder comprises a cylindrical surface and a conical surface which are sequentially connected in the vertical direction, a plurality of micro grooves are formed in the inner surface of a top dead center area of the cylindrical surface, and in the running process of the engine, the piston and the piston ring respectively rub with the inner wall of the cylinder hole to generate friction work, and the piston knocks the cylinder to generate knocking kinetic energy; the design method comprises the following steps: through carrying out simulation experiments by utilizing fluid dynamics simulation software and carrying out experiments on an engine bench, a dynamics model representing the corresponding relation between the shape parameters of the cylinder hole, the friction work and the knocking kinetic energy is obtained; according to the dynamics model, multiple groups of first data used for representing the corresponding relations between structures of different micro grooves and peaks of friction work and knocking kinetic energy are obtained, and multiple groups of second data used for representing the corresponding relations between molded line parameters of different cylindrical surfaces and conical surfaces and peaks of friction work and knocking kinetic energy are obtained; and obtaining the micro-groove structure, the cylindrical surface and the profile parameters of the conical surface corresponding to the minimum value of friction work and the minimum value of the peak value of knocking kinetic energy in the plurality of groups of first data and the plurality of groups of second data.
According to an embodiment of the present invention, the design method further includes: based on an orthogonal test, obtaining the influence weights of the profile parameters of the micro groove structure, the cylindrical surface and the conical surface on the friction work and the peak value of the knocking kinetic energy, and obtaining the profile parameters of the micro groove structure, the cylindrical surface and the conical surface corresponding to the minimum value of the friction work and the minimum value of the peak value of the knocking kinetic energy in a plurality of groups of first data and a plurality of groups of second data based on the kinetic model according to the influence weights.
According to an embodiment of the present invention, by performing a simulation experiment using hydrodynamic simulation software and performing an experiment on an engine mount, a dynamic model representing a correspondence between a shape parameter of the cylinder bore and the friction work and the knocking kinetic energy is obtained, including: the method comprises the steps of performing simulation experiments by utilizing fluid dynamics simulation software to obtain first friction work generated by friction between the piston corresponding to different shape parameters of cylinder holes and the piston ring and the inner wall of the cylinder hole of the cylinder respectively, and first knocking kinetic energy of knocking the cylinder by the piston to form a first dynamics model; obtaining second friction work generated by friction between the piston corresponding to different shape parameters of the cylinder hole and the piston ring and the inner wall of the cylinder hole of the cylinder and second knocking kinetic energy of the piston knocking the cylinder through experiments on the engine; and adjusting the first dynamics model according to the difference value of the first friction work and the second friction work and the difference value of the first knocking kinetic energy and the second knocking kinetic energy to obtain a calibrated second dynamics model.
According to the embodiment of the invention, the second dynamics model comprises a third friction work and a third knocking kinetic energy, wherein the third friction work and the third knocking kinetic energy are obtained through calibration, the absolute value of the difference value of the third friction work and the second friction work is 5% of the second friction work, and the absolute value of the difference value of the third knocking kinetic energy and the second knocking kinetic energy is 5% of the second knocking kinetic energy.
According to an embodiment of the present invention, by performing simulation experiments using fluid dynamics simulation software, a first friction work generated by friction between the piston and the piston ring, which are characterized by corresponding to different shape parameters of the cylinder bore, and an inner wall of the cylinder bore of the cylinder, respectively, and a first striking kinetic energy of the piston striking the cylinder are obtained, and a first dynamics model is formed, including: based on fluid dynamics simulation software, establishing a three-dimensional model comprising the piston, the piston ring and a cylinder hole of the cylinder; performing finite element mesh division on the three-dimensional model to form a finite element model; loading the finite element model with a thermal load and a mechanical load; obtaining a deformation amount of a cylinder hole of the cylinder under the action of the thermal load and the mechanical load; and obtaining the first dynamics model according to the shape parameter of the cylinder hole of the cylinder and the deformation of the cylinder hole of the cylinder.
According to an embodiment of the present invention, the mechanical load includes at least one of a bolt pretightening force between a cylinder head and a cylinder of the engine, a cylinder implosion pressure of the cylinder, and a side impact force caused by the reciprocating motion of the piston to the cylinder bore; and/or the thermal load is at least one of gas temperature and convective heat transfer coefficient.
According to an embodiment of the invention, the micro grooves are generally circular pits; according to the second dynamics model, adopting a single variable method to respectively obtain the corresponding relation of the diameter of the pit, the ratio of the sum of the areas of a plurality of pits to the area of the top dead center, the depth of the pit and the peak value of the third friction work and the third knocking kinetic energy; wherein the diameter of the pit ranges from 150 to 250 mu m, the ratio of the sum of the areas of a plurality of pits to the area of the top dead center area ranges from 20 to 40 percent, and the depth of the pit ranges from 0.1 to 0.9mm.
According to the embodiment of the invention, the cross section of the cylindrical surface and the cross section of the conical surface are elliptical; according to a second dynamics model, adopting a single variable method to respectively obtain the corresponding relation of the taper of the conical surface, the height of the cylindrical surface, the ellipticity of the cross section of the cylindrical surface, the third friction work and the peak value of the third knocking kinetic energy; the taper A of the conical surface is 0 μm < A < 100 μm, the height B of the cylindrical surface is 0mm < B < 100mm, and the ellipticity C of the cross section of the cylindrical surface is 0 μm < C < 150 μm.
According to an embodiment of the present invention, the micro-groove is a substantially circular pit, and the cross section of the cylindrical surface and the cross section of the conical surface are both elliptical; based on an orthogonal experiment, obtaining the influence weights of the structures of the micro grooves, the profile parameters of the cylindrical surface and the conical surface on the friction work and the peak value of the knocking kinetic energy, wherein the method comprises the following steps: based on an orthogonal experiment, obtaining an orthogonal table comprising the level of influencing factors of the conicity of the conical surface, the height of the cylindrical surface, the ellipticity of the cross section of the cylindrical surface, the diameter of the pit, the ratio of the sum of the areas of the pits to the area of the top dead center, the depth of the pit, the peak value of friction work and knocking kinetic energy; obtaining first extreme differences of influence factor levels of a plurality of groups of friction work and peak values of knocking kinetic energy corresponding to different conical surfaces, different heights of cylindrical surfaces, different ovality of cross sections of the cylindrical surfaces, different diameters of pits, different ratios of sum of areas of a plurality of pits to top dead center area and different depths of the pits respectively according to the orthogonal table; and comparing the sizes of the first polar differences to obtain the conicity of the conical surface, the height of the cylindrical surface, the ellipticity of the cross section of the cylindrical surface, the diameter of the pit, the ratio of the sum of the areas of the pit to the area of the top dead center, and the influence weight of the depth of the pit on the friction work and the peak value of the knocking kinetic energy.
According to an embodiment of the present invention, based on an orthogonal experiment, an influence weight of a profile parameter of the micro groove structure, the cylindrical surface, and the conical surface on the peak values of the friction work and the knocking kinetic energy is obtained, and the method further includes: obtaining second extreme differences of the impact factor levels of peaks of friction work and knocking kinetic energy corresponding to any two of different conical surfaces, different heights of cylindrical surfaces, different ovality of cross sections of the cylindrical surfaces, different diameters of pits, different ratios of sum of areas of a plurality of pits to top dead center area and different depths of the pits according to the orthogonal table; and comparing the magnitude of the second polar differences to obtain the magnitude of the degree of correlation of any two of the taper of the conical surface, the height of the cylindrical surface, the ellipticity of the cross section of the cylindrical surface, the diameter of the pit, the ratio of the sum of the areas of the pits to the area of the top dead center and the depth of the pit on the peak influence on the friction work and the knocking kinetic energy.
According to the design method of the cylinder hole of the engine, according to the embodiment of the invention, simulation experiments are carried out by utilizing fluid dynamics simulation software, the engine is subjected to experiments on an engine bench, a dynamic model representing the corresponding relation between the shape parameter of the cylinder hole, friction work and knocking kinetic energy is obtained, and the structure of a micro groove corresponding to the minimum value of the friction work and the minimum value of the peak value of the knocking kinetic energy and the line parameters of the cylindrical surface and the conical surface of the cylinder hole of the cylinder are obtained according to the dynamic model. In order to optimize the structure of the cylinder hole of the cylinder of the engine, and simultaneously, the friction loss between the piston and the piston ring and the inner wall of the cylinder hole of the cylinder respectively and the knocking kinetic energy generated when the piston knocks the inner wall of the cylinder hole of the cylinder are reduced.
Drawings
FIG. 1 is a cross-sectional view of a cylinder bore of an engine according to an embodiment of the present invention;
FIG. 2 is a top view of a cylinder bore of an engine according to an embodiment of the present invention;
FIG. 3 is a cross-sectional view of a micro groove on the inner wall of a cylinder bore of an engine of an embodiment of the present invention along the axial direction of the cylinder bore;
FIG. 4 is a cross-sectional view of a micro groove on the inner wall of a cylinder bore of an engine along the radial direction of the cylinder bore of an embodiment of the present invention;
FIG. 5 is a flow chart of a method of designing a cylinder bore of an engine according to an embodiment of the present invention; and
Fig. 6 is a schematic diagram of an orthogonal table of an orthogonal experiment of a method of designing a cylinder bore of an engine according to an embodiment of the present invention.
In the figure:
1-a cylinder hole;
11-cylindrical surface; 111-top dead center region; 112-micro-grooves;
12-conical surface.
Detailed Description
The present invention will be further described in detail below with reference to specific embodiments and with reference to the accompanying drawings, in order to make the objects, technical solutions and advantages of the present invention more apparent.
According to the invention, in the running process of the engine, the piston and the piston ring respectively rub with the inner wall of the cylinder hole to generate friction work, and the piston knocks the cylinder to generate knocking kinetic energy; the design method comprises the following steps: the method comprises the steps of performing simulation experiments by utilizing fluid dynamics simulation software and performing experiments on an engine bench to obtain a dynamics model representing the corresponding relation between shape parameters, friction work and knocking kinetic energy of a cylinder hole; according to the dynamics model, multiple groups of first data used for representing the corresponding relation between the structures of different micro-grooves and the peaks of friction work and knocking kinetic energy are obtained, and multiple groups of second data used for representing the corresponding relation between the molded line parameters of different cylindrical surfaces and conical surfaces and the peaks of friction work and knocking kinetic energy are obtained; and obtaining the profile parameters of the micro groove structure, the cylindrical surface and the conical surface corresponding to the minimum value of the friction work and the minimum value of the peak value of the knocking kinetic energy in the plurality of groups of first data and the plurality of groups of second data.
FIG. 1 is a cross-sectional view of a cylinder bore of an engine according to an embodiment of the present invention; FIG. 2 is a top view of a cylinder bore of an engine according to an embodiment of the present invention; FIG. 3 is a cross-sectional view of a micro groove on the inner wall of a cylinder bore of an engine of an embodiment of the present invention along the axial direction of the cylinder bore; FIG. 4 is a cross-sectional view of a micro groove on the inner wall of a cylinder bore of an engine along the radial direction of the cylinder bore of an embodiment of the present invention; fig. 5 is a flowchart of a method of designing a cylinder bore of an engine according to an embodiment of the present invention.
Referring to fig. 1-5, a method of designing a cylinder bore of an engine is provided in accordance with an exemplary embodiment of the present invention. The engine includes a piston, a piston ring, and a cylinder. The cylinder bore 1 of the cylinder includes a cylindrical surface 11 and a conical surface 12 connected in sequence in the vertical direction, and the inner surface of a top dead center region 111 of the cylindrical surface 11 is provided with a plurality of micro grooves 112. During the running process of the engine, the piston and the piston ring respectively rub with the inner wall of the cylinder hole 1 to generate friction work, and the piston knocks the cylinder to generate knocking kinetic energy. The design method comprises the following steps: by utilizing fluid dynamics simulation software to carry out simulation experiments and carrying out experiments on an engine bench, a dynamics model representing the corresponding relation between the shape parameters of the cylinder hole, friction work and knocking kinetic energy is obtained. According to the dynamic model, multiple groups of first data used for representing the corresponding relation between the structures of different micro-grooves and the peaks of friction work and knocking kinetic energy are obtained, and multiple groups of second data used for representing the corresponding relation between the molded line parameters of different cylindrical surfaces and conical surfaces and the peaks of friction work and knocking kinetic energy are obtained. And obtaining the profile parameters of the structure, the cylindrical surface and the conical surface of the micro groove corresponding to the minimum value of the friction work and the minimum value of the peak value of the knocking kinetic energy in the plurality of groups of first data and the plurality of groups of second data.
In this embodiment, by performing a simulation experiment using hydrodynamic simulation software and performing an experiment on an engine rack, a dynamic model representing a correspondence between a shape parameter of a cylinder hole and friction work and knocking kinetic energy is obtained, and a structure of a micro groove corresponding to a minimum value of the friction work and a minimum value of a peak value of the knocking kinetic energy, and profile parameters of a cylindrical surface and a conical surface of the cylinder hole of the cylinder are obtained according to the dynamic model. The structure of the cylinder hole of the cylinder of the engine is optimized, so that the gap between the moving surface of the piston ring and the inner wall of the cylinder hole of the cylinder and the gap between the piston and the inner wall of the cylinder hole of the cylinder are respectively adjusted, the oil film distribution between the piston and the inner wall of the cylinder hole of the cylinder and between the piston ring and two pairs of friction pairs of the inner wall of the hole of the cylinder is improved, the friction loss between the piston and the piston ring and the inner wall of the cylinder hole of the cylinder respectively can be reduced, and the knocking kinetic energy generated by the piston knocking the inner wall of the cylinder hole of the cylinder can be reduced.
In this embodiment, the profile parameters of the cylindrical surface and the conical surface refer to the geometric parameters of the cylindrical surface and the conical surface.
In some exemplary embodiments, referring to fig. 5, the design method further comprises: based on an orthogonal test, obtaining the influence weights of the profile parameters of the micro-groove structure, the cylindrical surface and the conical surface on the friction work and the peak value of the knocking kinetic energy, and obtaining the profile parameters of the micro-groove structure, the cylindrical surface and the conical surface corresponding to the minimum value of the friction work and the minimum value of the peak value of the knocking kinetic energy in a plurality of groups of first data and a plurality of groups of second data based on a dynamics model according to the influence weights.
In some exemplary embodiments, obtaining a kinetic model characterizing a correspondence between shape parameters of a cylinder bore and friction work and tap kinetic energy by performing simulation experiments using hydrodynamic simulation software and performing experiments on an engine bench, includes: by utilizing fluid dynamics simulation software to carry out simulation experiments, first friction work generated by friction between pistons and piston rings corresponding to different shape parameters of cylinder holes and the inner wall of the cylinder hole of the cylinder and first knocking kinetic energy of the piston knocking the cylinder are obtained to form a first dynamics model. Through experiments on the engine bench, second friction work generated by friction between the piston corresponding to different shape parameters of the cylinder hole and the piston ring and the inner wall of the cylinder hole of the cylinder and second knocking kinetic energy of the piston knocking the cylinder are obtained. And adjusting the first dynamics model according to the difference value of the first friction work and the second friction work and the difference value of the first knocking kinetic energy and the second knocking kinetic energy to obtain a calibrated second dynamics model.
In this embodiment, the engine is tested on the engine bench, and the second friction work of the two pairs of friction pairs of the piston and the inner wall of the cylinder hole of the cylinder and the piston ring and the inner wall of the cylinder hole of the cylinder and the second knocking kinetic energy of the piston knocking the inner wall of the cylinder hole of the cylinder are obtained by measuring the second friction work of the two pairs of friction pairs of the piston and the inner wall of the cylinder hole of the cylinder and the knocking noise of the piston knocking the inner wall of the cylinder hole of the cylinder.
In some exemplary embodiments, the second kinetic model includes a third frictional work and a third kinetic energy of the first kinetic energy of the tap calibrated to an absolute value of a difference between the third frictional work and the second frictional work of 5% and an absolute value of a difference between the third kinetic energy of the tap and the second kinetic energy of the tap of 5% of the second kinetic energy of the tap.
In some exemplary embodiments, by performing simulation experiments using fluid dynamics simulation software, a first friction work generated by friction between a piston and a piston ring corresponding to shape parameters of different cylinder holes and an inner wall of the cylinder hole of a cylinder respectively, and a first knocking kinetic energy of the piston knocking the cylinder are obtained to form a first dynamics model, including: based on the fluid dynamics simulation software, a three-dimensional model of a cylinder bore including a piston, a piston ring, and a cylinder is built. And carrying out finite element mesh division on the three-dimensional model to form a finite element model. The finite element model is loaded with thermal and mechanical loads. The deformation amount of the cylinder hole of the cylinder under the action of the thermal load and the mechanical load is obtained. And obtaining a first dynamics model according to the shape parameters of the cylinder hole of the cylinder and the deformation quantity of the cylinder hole of the cylinder.
In this embodiment, in the process of establishing the first dynamic model by performing a simulation experiment using the fluid dynamic simulation software, chamfer angles of less than 2mm and rounding in the three-dimensional solid model of the piston-piston ring-cylinder bore are deleted, so as to improve the calculation efficiency without affecting the technical effect.
Further, in the process of carrying out finite element mesh division on the three-dimensional model, mesh layout encryption is carried out on the inner wall of a cylinder hole of the cylinder, and the mesh type is tetrahedral mesh.
In some exemplary embodiments, the mechanical load includes at least one of a bolt preload between a head and a cylinder of the engine, an in-cylinder burst pressure of the cylinder, and a side impact force on the cylinder bore caused by the piston reciprocation. The heat load is at least one of the gas temperature and the convective heat transfer coefficient.
In some exemplary embodiments, referring to fig. 3-4, the micro grooves are generally circular pits. And according to the second dynamics model, adopting a single variable method to respectively obtain the corresponding relation between the diameter of the pit, the ratio of the sum of the areas of the pits to the area of the top dead center and the depth of the pit, the third friction work and the peak value of the third knocking kinetic energy. Wherein the diameter d of the pit ranges from 150 to 250 mu m, the ratio of the sum of the areas of a plurality of pits to the area of the top dead center area ranges from 20 to 40%, and the depth h of the pit ranges from 0.1 to 0.9mm.
In the present embodiment, referring to fig. 3 to 4, the micro grooves are substantially circular pits, the diameter d of each pit ranges from 150 μm to 250 μm, the depth h of each pit ranges from 0.1mm to 0.9mm, and the ratio of the sum of the areas of the plurality of pits to the area of the top dead center region ranges from 20% to 40%.
In some exemplary embodiments, referring to fig. 1-2, the cross-section of the cylindrical surface and the cross-section of the conical surface are both elliptical. And according to the second dynamics model, adopting a single variable method to respectively obtain the corresponding relation between the three of the taper of the conical surface, the height of the cylindrical surface and the ellipticity of the cross section of the cylindrical surface and the peak value of the third friction work and the third knocking kinetic energy. Wherein the taper A of the conical surface is in the range of 0 μm < A.ltoreq.100 μm, the height B of the cylindrical surface is in the range of 0mm < B.ltoreq.100 mm, and the ovality C of the cross section of the cylindrical surface is in the range of 0 μm < C.ltoreq.150 μm.
In this embodiment, referring to fig. 1 to 2, the cross section of the cylindrical surface is an ellipse, the minor axis diameter of the ellipse is L, and the ellipticity C of the cross section of the cylindrical surface is in the range of 0 μm < c.ltoreq.150 μm. In other words, the major axis diameter of the cross section of the cylindrical surface is l+2c. The taper A of the conical surface ranges from 0 μm < A.ltoreq.100 μm, that is, the minor axis diameter of the largest cross section of the conical surface is L+2A. The height B of the cylindrical surface is in the range of 0mm < B.ltoreq.100 mm, in other words the distance of the top of the conical surface from the top of the cylinder bore of the cylinder is B.
In some exemplary embodiments, the micro grooves are generally circular pits, and the cross section of the cylindrical surface and the cross section of the conical surface are elliptical. Based on orthogonal experiments, obtaining the influence weights of the profile parameters of the structure, the cylindrical surface and the conical surface of the micro-groove on the peak values of friction work and knocking kinetic energy, wherein the method comprises the following steps: based on orthogonal experiments, orthogonal tables including the level of influencing factors including the taper of the conical surface, the height of the cylindrical surface, the ellipticity of the cross section of the cylindrical surface, the diameter of the pit, the ratio of the sum of the areas of the pits to the area of the top dead center, the depth of the pit, the peak value of friction work and knocking kinetic energy are obtained. And obtaining a first range of influence factor levels of a plurality of groups of friction work and peak values of knocking kinetic energy corresponding to different conical surfaces, different heights of cylindrical surfaces, ovality of cross sections of the cylindrical surfaces, different diameters of pits, a ratio of the sum of areas of the pits to the area of the top dead center and depths of the pits respectively according to an orthogonal table. Comparing the sizes of the first polar differences to obtain the influence weights of the conicity of the conical surface, the height of the cylindrical surface, the ellipticity of the cross section of the cylindrical surface, the diameter of the pit, the ratio of the sum of the areas of the pits to the area of the top dead center and the depth of the pit on the peak value of friction work and knocking kinetic energy.
In some exemplary embodiments, based on orthogonal experiments, obtaining the impact weights of the profile parameters of the structure, the cylindrical surface and the conical surface of the micro-groove on the peaks of friction work and knocking kinetic energy, further comprises: according to the orthogonal table, the second extreme difference of the impact factor level of the peak value of the friction work and the knocking kinetic energy corresponding to the combination of any two of the conical degrees of different conical surfaces, the heights of different cylindrical surfaces, the ovality of the cross sections of different cylindrical surfaces, the diameters of different pits, the ratio of the sum of the areas of different pits to the area of the top dead center and the depth of different pits is obtained. Comparing the sizes of the second polar differences to obtain the degree of correlation of any two of the conicity of the conical surface, the height of the cylindrical surface, the ellipticity of the cross section of the cylindrical surface, the diameter of the pit, the ratio of the sum of the areas of the pits to the area of the top dead center and the depth of the pit on the influence on the peak value of friction work and knocking kinetic energy.
Fig. 6 is a schematic diagram of an orthogonal table of an orthogonal experiment of a method of designing a cylinder bore of an engine according to an embodiment of the present invention.
In this example, referring to fig. 6, an orthogonal experiment was designed as an orthogonal design table of L27-3-13, and six-factor three-level orthogonal calculation was performed.
Six factors are the diameter of the pit, the depth of the pit, the ratio of the sum of the areas of a plurality of pits to the area of the top dead center area, the taper of the conical surface, the height of the cylindrical surface and the ellipticity of the cross section of the cylindrical surface. Three levels are provided with three factor-affecting level values for each factor.
In detail, as shown in fig. 6, column numbers 1 to 13 represent factors that affect friction work of two pairs of friction pairs of the piston and the inner wall of the cylinder bore of the cylinder, and the piston ring and the inner wall of the cylinder bore of the cylinder, respectively, and peaks of striking kinetic energy generated by the piston striking the cylinder, such as a diameter of the pit, a depth of the pit, a ratio of a sum of areas of the plurality of pits to an area of the top dead center, a taper of the conical surface, a height of the cylindrical surface, an ellipticity of a cross section of the cylindrical surface, a combination of a diameter of the pit and a depth of the pit, a combination of a taper of the conical surface and an ellipticity of a cross section of the cylindrical surface, and the like. Test nos. 1 to 27 represent 27 sets of tests performed under any one of the variable factors of column nos. 1 to 13, respectively, and 27 sets of influence factor levels corresponding to any one of the variable factors of column nos. 1 to 13 are obtained. Among the 27 groups of influence factor levels, 9 groups each have influence factor level values of 1, 2, and 3.
The following description is made regarding the extremely bad calculation method in the orthogonal experiment in this embodiment:
Taking the variable factor with the column number of 1 as an example, setting the variable factor with the column number of 1 as the diameter of the pit, and taking the orthogonal table as a basis, it can be seen that the level value of the influence factor of the 9 groups of tests with the test numbers of 1-9 is 1, and summing the input values of the diameters of the pits corresponding to the 9 groups of tests to obtain R1; the level value of the influencing factor of the 9 groups of tests with test numbers of 10-18 is 2, and the input values of the diameters of the pits corresponding to the 9 groups of tests are summed to be R2; the influence factor level value of the 9 sets of tests 19-27 is 3, and the input values of the diameters of the pits corresponding to the 9 sets of tests are summed to be R3. And (3) performing difference between the maximum value and the minimum value of R1, R2 and R3 to obtain a first extreme difference of the influence factor level of the peak value of the friction work and the knocking kinetic energy corresponding to the diameter of the pit. And by analogy, the first range of the impact factor levels of the peak values of the friction work and the knocking kinetic energy, which correspond to the five parts of the depth of the pit, the ratio of the sum of the areas of the pits to the area of the top dead center, the taper of the conical surface, the height of the cylindrical surface and the ellipticity of the cross section of the cylindrical surface, respectively, can be obtained in the mode.
Further, setting column number 7 as a variable factor of a combination of the diameter of the pit and the depth of the pit, it can be seen from the orthogonal table that the influence factor level values of the 9 sets of tests with test numbers 1,4, 7, 11, 14, 17, 21, 24, 27 are 1, and the input values of the diameter of the pit and the depth of the pit corresponding to the 9 sets of tests are summed up to be R4; the level value of the influencing factors of the 9 groups of tests with test numbers of 2, 5, 8, 12, 15, 18, 19, 22 and 25 is 2, and the input values of the diameters of the pits and the depths of the pits corresponding to the 9 groups of tests are summed to be R5; the influence factor level value of the 9 groups of tests with test numbers of 3, 6, 9, 10, 13, 16, 20, 23 and 26 is 3, and the input values of the diameter of the pit and the depth of the pit corresponding to the 9 groups of tests are summed to be R6. And (3) performing difference between the maximum value and the minimum value in R4, R5 and R6 to obtain a second extreme difference of the influence factor level of the peak value of the friction work and the knocking kinetic energy corresponding to the combination of the diameter of the pit and the depth of the pit. And so on, the second extreme difference of the impact factor level of the peak value of the friction work and the knocking kinetic energy corresponding to the combination of any two of the conical surface conicity, the cylindrical surface height, the cylindrical surface cross section ellipticity, the pit diameter, the sum of the pit areas and the top dead center area, and the pit depth.
The larger the first range, the larger the influence of the factor on the friction work of two pairs of friction pairs between the piston and the inner wall of the cylinder hole of the cylinder and between the piston ring and the inner wall of the cylinder hole of the cylinder; on the contrary, the smaller the influence of the factor on the friction work of the two friction pairs of the piston and the inner wall of the cylinder bore of the cylinder and the piston ring and the inner wall of the cylinder bore of the cylinder. Further, the larger the second range, the stronger the interaction that exists between the two factors; conversely, the weaker the interaction that exists between the two factors.
Further, in this embodiment, in the process of obtaining the micro-groove structure, the cylindrical surface and the conical surface profile parameters corresponding to the minimum value of the friction work and the minimum value of the peak value of the striking kinetic energy in the plurality of sets of first data and the plurality of sets of second data, the piston air leakage is required to be considered in addition to the minimum value of the friction work and the minimum value of the peak value of the striking kinetic energy, so as to determine the optimal parameters of the micro-groove structure, the cylindrical surface and the conical surface profile parameters.
In addition, in the related art, the method for reducing the friction work of two pairs of friction pairs of the piston and the inner wall of the cylinder hole and the piston ring and the inner wall of the cylinder hole and reducing the knocking kinetic energy generated by knocking the piston on the inner wall of the cylinder hole comprises the following three steps:
The first method is to improve the friction lubrication and knocking characteristics of the piston from the perspective of the structural design of the piston, and by carrying out parameter optimization design on the skirt profile of the piston, the friction work of a friction pair between the piston and the inner wall of a cylinder hole of the cylinder can be effectively reduced, and the knocking kinetic energy generated by knocking the piston on the inner wall of the cylinder hole of the cylinder can be effectively reduced.
The second method is to adopt a non-cylindrical cylinder sleeve design in a cold state from the design angle of a hole line of a cylinder, and adjust the distribution of a lubricating oil film by adjusting the gaps between a piston ring and the inner wall of the hole of the cylinder and between a piston and two pairs of friction pairs on the inner wall of the hole of the cylinder, so that the friction loss is reduced. However, the current non-cylindrical cylinder liner design is mainly aimed at reducing friction work by adjusting the gap between two pairs of friction pairs, and neglecting the negative effect of increased noise of piston striking the inner wall of the cylinder bore caused by the excessive gap between the two pairs of friction pairs.
The third method is that micro grooves are arranged on the inner wall of a cylinder hole, and the structural parameters of the micro grooves on the inner wall of the cylinder hole are optimally designed to reduce friction losses between a piston and the inner wall of the cylinder hole and between a piston ring and two pairs of friction pairs on the inner wall of the cylinder hole, but the improvement of knocking kinetic energy generated by knocking the piston on the inner wall of the cylinder hole is limited to a certain extent.
The design method of the cylinder bore of the engine of the present embodiment obtains a macroscopic and microscopic combined cylinder bore design method by optimizing the shape parameters of the cylinder bore of the cylinder and the structure of the micro grooves provided on the inner wall of the cylinder bore of the cylinder. In other words, macroscopically, the cylinder hole of the cylinder comprises a cylindrical surface and a conical surface which are sequentially connected in the vertical direction, and the cross section of the cylindrical surface and the cross section of the conical surface are elliptical. Microcosmically, a micro groove is arranged in the upper dead point area of the inner wall of the cylinder hole of the cylinder. Based on a construction dynamics model and an orthogonal test, the profile parameters of the cylindrical surface and the conical surface of the cylinder hole of the cylinder and the geometric parameters of the micro groove are optimally designed, and the optimal parameters of the profile parameters of the cylindrical surface and the conical surface of the cylinder hole of the cylinder and the geometric parameters of the micro groove are obtained, wherein the minimum value of friction work of two pairs of friction pairs of the piston ring and the inner wall of the cylinder hole of the cylinder and the inner wall of the cylinder hole of the piston and the piston, and the minimum value of the peak value of knocking kinetic energy generated by the piston knocking the cylinder are corresponding to each other.
Further, the design method of the cylinder hole of the engine effectively reduces friction work of two pairs of friction pairs between the piston ring and the inner wall of the cylinder hole of the cylinder and between the piston and the inner wall of the cylinder hole of the cylinder, and effectively reduces peak value of knocking kinetic energy generated by knocking the cylinder by the piston. The technical defect that in the prior art, only a cylinder hole of a non-cylindrical cylinder is adopted or only a micro groove is arranged on the inner wall of the cylinder hole of the cylinder is overcome, and the peak value of knocking kinetic energy generated by knocking the cylinder by a piston is too high, so that the improvement is difficult is overcome.
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the invention thereto, but to limit the invention thereto, and any modifications, equivalents, improvements and equivalents thereof may be made without departing from the spirit and principles of the invention.

Claims (10)

1. The design method of a cylinder hole of an engine comprises a piston, a piston ring and a cylinder, wherein the cylinder hole (1) of the cylinder comprises a cylindrical surface (11) and a conical surface (12) which are sequentially connected in the vertical direction, a plurality of micro grooves (112) are formed in the inner surface of a top dead center area (111) of the cylindrical surface (11), and in the running process of the engine, the piston and the piston ring respectively rub with the inner wall of the cylinder hole (1) to generate friction work, and the piston knocks the cylinder to generate knocking kinetic energy;
The design method comprises the following steps:
Through carrying out simulation experiments by utilizing fluid dynamics simulation software and carrying out experiments on an engine bench, a dynamics model representing the corresponding relation between the shape parameters of the cylinder hole, the friction work and the knocking kinetic energy is obtained;
According to the dynamics model, multiple groups of first data used for representing the corresponding relations between structures of different micro grooves and peaks of friction work and knocking kinetic energy are obtained, and multiple groups of second data used for representing the corresponding relations between molded line parameters of different cylindrical surfaces and conical surfaces and peaks of friction work and knocking kinetic energy are obtained; and
And obtaining the micro-groove structure, the cylindrical surface and the profile parameters of the conical surface corresponding to the minimum value of friction work and the minimum value of the peak value of knocking kinetic energy in the plurality of groups of first data and the plurality of groups of second data.
2. The method for designing a cylinder bore of an engine according to claim 1, further comprising:
Based on an orthogonal test, obtaining the influence weights of the profile parameters of the micro groove structure, the cylindrical surface and the conical surface on the friction work and the peak value of the knocking kinetic energy, and obtaining the profile parameters of the micro groove structure, the cylindrical surface and the conical surface corresponding to the minimum value of the friction work and the minimum value of the peak value of the knocking kinetic energy in a plurality of groups of first data and a plurality of groups of second data based on the kinetic model according to the influence weights.
3. The method for designing a cylinder bore of an engine according to claim 1, wherein obtaining a dynamic model representing a correspondence relationship between the shape parameter of the cylinder bore and the friction work and the knocking kinetic energy by performing a simulation experiment using a fluid dynamic simulation software and performing an experiment on the engine on an engine block, comprises:
the method comprises the steps of performing simulation experiments by utilizing fluid dynamics simulation software to obtain first friction work generated by friction between the piston corresponding to different shape parameters of cylinder holes and the piston ring and the inner wall of the cylinder hole of the cylinder respectively, and first knocking kinetic energy of knocking the cylinder by the piston to form a first dynamics model;
Obtaining second friction work generated by friction between the piston corresponding to different shape parameters of the cylinder hole and the piston ring and the inner wall of the cylinder hole of the cylinder and second knocking kinetic energy of the piston knocking the cylinder through experiments on the engine; and
And adjusting the first dynamics model according to the difference value of the first friction work and the second friction work and the difference value of the first knocking kinetic energy and the second knocking kinetic energy to obtain a calibrated second dynamics model.
4. The method for designing a cylinder bore of an engine according to claim 3, wherein the second dynamics model includes a third friction work and a third knocking kinetic energy, the third friction work and the second friction work being calibrated, an absolute value of a difference between the third friction work and the second friction work being 5% of the second friction work, and an absolute value of a difference between the third knocking kinetic energy and the second knocking kinetic energy being 5% of the second knocking kinetic energy.
5. A method of designing a cylinder bore of an engine according to claim 3, wherein first kinetic models are formed by performing simulation experiments using fluid dynamics simulation software to obtain first frictional work characterizing friction of the piston and the piston ring with inner walls of the cylinder bore of the cylinder, respectively, corresponding to different shape parameters of the cylinder bore, and first striking kinetic energy of the piston striking the cylinder, respectively, comprising:
based on fluid dynamics simulation software, establishing a three-dimensional model comprising the piston, the piston ring and a cylinder hole of the cylinder;
Performing finite element mesh division on the three-dimensional model to form a finite element model;
loading the finite element model with a thermal load and a mechanical load;
Obtaining a deformation amount of a cylinder hole of the cylinder under the action of the thermal load and the mechanical load; and
And obtaining the first dynamics model according to the shape parameters of the cylinder hole of the cylinder and the deformation of the cylinder hole of the cylinder.
6. The method for designing a cylinder bore of an engine according to claim 5, wherein the mechanical load includes at least one of a bolt preload between a cylinder head and a cylinder of the engine, an in-cylinder explosion pressure of the cylinder, and a side impact force caused to the cylinder bore by the reciprocating motion of the piston; and/or
The thermal load is at least one of gas temperature and convective heat transfer coefficient.
7. The method for designing a cylinder bore of an engine according to claim 4, wherein the micro grooves are substantially circular pits;
according to the second dynamics model, adopting a single variable method to respectively obtain the corresponding relation of the diameter of the pit, the ratio of the sum of the areas of a plurality of pits to the area of the top dead center, the depth of the pit and the peak value of the third friction work and the third knocking kinetic energy;
wherein the diameter of the pit ranges from 150 to 250 mu m, the ratio of the sum of the areas of a plurality of pits to the area of the top dead center area ranges from 20 to 40 percent, and the depth of the pit ranges from 0.1 to 0.9mm.
8. The method for designing a cylinder bore of an engine according to claim 4, wherein the cross section of the cylindrical surface and the cross section of the conical surface are both elliptical;
According to a second dynamics model, adopting a single variable method to respectively obtain the corresponding relation of the taper of the conical surface, the height of the cylindrical surface, the ellipticity of the cross section of the cylindrical surface, the third friction work and the peak value of the third knocking kinetic energy;
The taper A of the conical surface is 0 μm < A < 100 μm, the height B of the cylindrical surface is 0mm < B < 100mm, and the ellipticity C of the cross section of the cylindrical surface is 0 μm < C < 150 μm.
9. The method for designing a cylinder bore of an engine according to claim 2, wherein the micro groove is a substantially circular pit, and a cross section of the cylindrical surface and a cross section of the conical surface are both elliptical;
Based on an orthogonal experiment, obtaining the influence weights of the structures of the micro grooves, the profile parameters of the cylindrical surface and the conical surface on the friction work and the peak value of the knocking kinetic energy, wherein the method comprises the following steps:
Based on an orthogonal experiment, obtaining an orthogonal table comprising the level of influencing factors of the conicity of the conical surface, the height of the cylindrical surface, the ellipticity of the cross section of the cylindrical surface, the diameter of the pit, the ratio of the sum of the areas of the pits to the area of the top dead center, the depth of the pit, the peak value of friction work and knocking kinetic energy;
Obtaining first extreme differences of influence factor levels of a plurality of groups of friction work and peak values of knocking kinetic energy corresponding to different conical surfaces, different heights of cylindrical surfaces, different ovality of cross sections of the cylindrical surfaces, different diameters of pits, different ratios of sum of areas of a plurality of pits to top dead center area and different depths of the pits respectively according to the orthogonal table; and
And comparing the sizes of the first polar differences to obtain the influence weights of the conicity of the conical surface, the height of the cylindrical surface, the ellipticity of the cross section of the cylindrical surface, the diameter of the pit, the ratio of the sum of the areas of the pits to the area of the top dead center and the depth of the pit on the friction work and the peak value of the knocking kinetic energy.
10. The method for designing a cylinder bore of an engine according to claim 9, wherein the influence weights of the structure of the micro groove, the line parameters of the cylindrical surface and the conical surface on the peak values of the friction work and the knocking kinetic energy are obtained based on orthogonal experiments, further comprising:
Obtaining second extreme differences of the impact factor levels of peaks of friction work and knocking kinetic energy corresponding to any two of different conical surfaces, different heights of cylindrical surfaces, different ovality of cross sections of the cylindrical surfaces, different diameters of pits, different ratios of sum of areas of a plurality of pits to top dead center area and different depths of the pits according to the orthogonal table; and
Comparing the magnitude of the second polar differences to obtain the magnitude of the degree of correlation of any two of the taper of the conical surface, the height of the cylindrical surface, the ellipticity of the cross section of the cylindrical surface, the diameter of the pit, the ratio of the sum of the areas of the pits to the area of the top dead center and the depth of the pit on the influence on the peak value of the friction work and the knocking kinetic energy.
CN202311833970.5A 2023-12-28 2023-12-28 Method for designing cylinder hole of engine Pending CN118133702A (en)

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