Engine assembly structure coordination hierarchical evaluation method

Abstract

The present application relates to a kind of engine combination structure coordination grading evaluation method, engine combination structure includes crankshaft body combination structure and body head combination structure two parts, each part is divided into two levels of evaluation, coordination evaluation factor is between 0~1, 1 indicates best, 0 indicates worst.The present application uses coordination grading evaluation, wherein first-level evaluation corresponds to conceptual design phase, second-level evaluation corresponds to scheme design phase.First-level evaluation can quickly respond to the stiffness, strength, vibration, lubrication and sealing of engine combination structure and other factors, to provide basis for overall scheme arrangement;After entering scheme design phase, with the improvement of model maturity, the influence of detail structure on stiffness, vibration and lubrication needs to be considered, wear, sealing and light weight need to be considered, and second-level evaluation can accurately find out the weak link of engine combination structure and provide direction and basis for structure improvement.

Description

Technical Field

[0001] This invention belongs to the field of engine technology, specifically relating to a method for graded evaluation of the coordination of engine assembly structures. Background Technology

[0002] Mechanical structures are becoming increasingly complex with advancements in science and technology and functional requirements. The demands for multi-structure and multidisciplinary collaborative design are constantly rising in the overall system design process, and current sequential structure design methods are increasingly failing to meet overall design requirements. Simultaneously, with the increasing demands for power density, lightweighting, and energy conservation and emission reduction in internal combustion engines, the various loads on the crankshaft-engine block assembly and the engine block-cylinder head assembly are significantly increasing, posing challenges to the overall reliability of the engine. To address these challenges, a coordinated and matched overall evaluation index system analysis should be conducted on the main load-bearing assembly structure of diesel engines to construct a multi-level, multi-index collaborative evaluation framework.

[0003] Traditional R&D processes can only analyze and evaluate single factors, failing to meet the needs of multi-objective evaluation. For example, there's the challenge of designing gas seals under high thermomechanical loads. Increasing cylinder head bolt preload increases sealing pressure and improves sealing performance, but it also increases cylinder liner deformation and reduces the fatigue safety factor of structural components. Therefore, it's necessary to coordinate the arrangement and distribution of cylinder head bolt loads, as well as the dimensions and shapes of key components, to ensure coordinated deformation of the combined structure while simultaneously meeting multiple objectives such as gas seal performance, cylinder liner deformation, and structural fatigue strength. Furthermore, the same specifications and standards are applied at different design stages, with significant differences in analysis and evaluation criteria, lacking a unified evaluation system. For instance, vibration analysis and evaluation are performed in both the conceptual design and schematic design stages, but traditional R&D processes use the same specifications for vibration intensity evaluation in both stages. If the vibration intensity exceeds the standard, no optimization direction can be provided. Summary of the Invention

[0004] To address the above technical problems, this invention provides a method for graded evaluation of the coordination of engine assembly structures, thus overcoming the shortcomings of existing technologies.

[0005] The technical solution of the present invention is: a method for graded evaluation of the coordination of engine assembly structure, characterized in that: the engine assembly structure includes two parts, a crankshaft and engine block assembly structure and an engine block and cylinder head assembly structure, each part is divided into two levels of evaluation, and the coordination evaluation factor is between 0 and 1, where 1 represents the best and 0 represents the worst.

[0006] The primary evaluation of the crankshaft housing structure includes five parts: strength compatibility evaluation, primary evaluation of main bearing bore deformation, vibration intensity evaluation, crankshaft torsional vibration evaluation, and primary evaluation of main bearing lubrication.

[0007] The secondary evaluation of the crankshaft and engine block assembly structure includes five parts: vibration coordination evaluation of the assembly structure, secondary coordination evaluation of main bearing bore deformation, vibration intensity coordination evaluation, secondary coordination evaluation of main bearing lubrication, coordination evaluation of main bearing wear, and lightweighting coordination evaluation.

[0008] The first-level evaluation of the engine block and cylinder head assembly structure includes five parts: strength compatibility evaluation, cylinder liner deformation first-level evaluation, vibration intensity evaluation, cylinder gasket sealing evaluation, and piston ring and cylinder liner lubrication first-level evaluation.

[0009] The secondary evaluation of the engine block and cylinder head assembly structure includes six parts: secondary evaluation of cylinder liner deformation, sealing evaluation, vibration evaluation, secondary evaluation of piston ring and cylinder liner lubrication, evaluation of piston ring and cylinder liner wear, and lightweight evaluation.

[0010] Beneficial Effects: This invention employs a hierarchical evaluation system, where Level 1 evaluation corresponds to the conceptual design stage and Level 2 evaluation corresponds to the scheme design stage. Because the model maturity is low and the analysis of boundary conditions is limited during the conceptual design stage, Level 1 evaluation can quickly reflect factors such as stiffness, strength, vibration, lubrication, and sealing of the engine assembly structure, providing a basis for the overall scheme layout. In the scheme design stage, as model maturity increases, it is necessary to consider the impact of detailed structures on stiffness, vibration, and lubrication, as well as the effects of wear, sealing, and weight reduction. Level 2 evaluation can accurately identify the weak points of the engine assembly structure and provide direction and basis for its improvement. Attached Figure Description

[0011] Figure 1 Crankshaft and engine block assembly structure primary evaluation framework diagram Figure 2 Crankshaft and engine block assembly structure primary evaluation radar chart Figure 3 Crankshaft and engine block assembly structure secondary evaluation framework diagram Figure 4 Crankshaft and engine block assembly structure secondary evaluation radar chart Figure 5 Engine block and cylinder head assembly structure first-level evaluation framework diagram Figure 6 Engine block and cylinder head assembly structure primary evaluation radar chart Figure 7 Engine block and cylinder head assembly structure secondary evaluation framework diagram Figure 8 Radar diagram of the secondary evaluation of the engine block and cylinder head assembly structure. Detailed Implementation

[0012] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below.

[0013] This invention proposes a graded evaluation method for the coordination of engine assembly structures, which consist of two parts: a crankshaft and engine block assembly, and an engine block and cylinder head assembly. Each part is evaluated at two levels. The coordination evaluation factor ranges from 0 to 1, with 1 representing the best and 0 representing the worst. The first-level evaluation can quickly reflect factors such as stiffness, strength, vibration, lubrication, and sealing of the engine assembly structure, providing a basis for the overall layout. The second-level evaluation can accurately identify the weak points of the engine assembly structure and provide direction and basis for its improvement.

[0014] The primary evaluation of the crankshaft and engine block assembly structure comprises five parts: strength compatibility evaluation, primary evaluation of main bearing bore deformation, vibration intensity evaluation, crankshaft torsional vibration evaluation, and primary evaluation of main bearing lubrication. The evaluation framework for the primary evaluation of the crankshaft and engine block assembly structure is as follows: Figure 1 As shown.

[0015] The overall coordination evaluation factor for the primary evaluation of the crankshaft and engine block assembly structure is defined as follows: (1) In the formula, As the intensity coordination factor,

[0016] Let be the fatigue safety factor of the i-th component. This is the fatigue safety factor limit value for the i-th component. and The weights are respectively the basic strength requirements and the equal life design components.

[0017] The first-order compatibility factor for main bearing bore deformation.

[0018] The maximum out-of-roundness of the main bearing section; The limit value for the out-of-roundness of the main bearing section. This is the minimum out-of-roundness value of the main bearing section.

[0019] Vibration intensity coordination factor

[0020] , and These refer to the vibration intensity, upper limit, and optimal value specified in the national standard for composite structures.

[0021] Crankshaft torsional vibration compatibility factor

[0022] , and These are the crankshaft torsional angular displacement values, the limit value, and the optimal value, respectively. , and These represent the maximum, limit, and optimal values ​​of crankshaft torsional stress, respectively. and These are the torsional angular displacement and torsional stress weights, respectively.

[0023] Primary coordination factor for main bearing lubrication.

[0024]

[0025] Minimum oil film thickness, This is the sum of the roughness of the bearing bush and the journal. and This refers to the peak oil film pressure and its limit value. and These are the weighting coefficients for lubrication condition and peak oil film pressure, respectively.

[0026] , , , and The weighting coefficients for the coordination factors are shown in Table 1.

[0027] Table 1. Weights of Sub-objectives for First-Level Evaluation of Crankshaft and Engine Block

[0028] Representing multiple coordination factor values ​​on a radar chart provides a quick and intuitive way to understand the reliability levels of various aspects of the analyzed object. Since each coordination factor ranges from 0 to 1, with 1 representing the best and 0 representing the worst, the radar chart qualitatively characterizes the relationship between these factors, quickly revealing which aspects of the combined structure have poor reliability, which are good, and whether the differences between multiple coordination factors are too large. This can provide direction and ideas for subsequent design improvements, such as... Figure 2 As shown.

[0029] The secondary evaluation of the crankshaft and engine block assembly structure comprises five parts: vibration compatibility evaluation of the assembly structure, secondary compatibility evaluation of main bearing bore deformation, vibration intensity compatibility evaluation, secondary compatibility evaluation of main bearing lubrication, secondary compatibility evaluation of main bearing wear, and lightweighting compatibility evaluation. The framework for the secondary evaluation of the assembly structure is as follows: Figure 3 As shown.

[0030] The overall coordination evaluation factor for the secondary evaluation of the crankshaft and engine block assembly structure is defined as follows: (2) In the formula, For the vibration compatibility factor of the composite structure,

[0031] These are the index factors for the natural frequency component, crankshaft vibration component, and cylinder block vibration component, respectively. These are the corresponding weighting coefficients.

[0032] Secondary compatibility factor for main bearing bore deformation.

[0033] , and These are the maximum out-of-roundness of the main bearing section, the difference in coaxiality between the main bearing journal and bearing bush, and the average total bearing offset, respectively. , and These are the limiting values ​​for the three mentioned above; , and These are the optimal and minimum values ​​for the three mentioned above.

[0034] Secondary coordination factor for main bearing lubrication.

[0035] This represents the average value of the bearing's peak oil film pressure. This represents the maximum limit of the average peak pressure of the oil film. The minimum value of the average peak pressure of the oil film is the optimal value. The total frictional loss power consumption per cycle of the friction pair This is the limit value for power consumption due to friction loss. It is the minimum value of frictional power loss. , , , The weighting coefficients for each indicator.

[0036] Main bearing wear compatibility factor

[0037] and These represent the wear rate of the friction pair per unit time during the break-in period and the steady-state period, respectively. and Each of them represents its limit value. and Each of them represents its optimal value. and These are their respective weights.

[0038] Lightweight coordination factor.

[0039]

[0040] For the first The quality of each component The mass limits for each component, The minimum value for each component is the optimal value.

[0041] , , , and The weighting coefficients are shown in Table 2.

[0042] Table 2 Weights of Secondary Evaluation Sub-objectives for Crankshaft and Engine Block

[0043] Representing multiple coordination factor values ​​on a radar chart can provide some direction and ideas for improving the design, such as... Figure 4 As shown.

[0044] The primary evaluation of the engine block and cylinder head assembly structure comprises five parts: strength compatibility evaluation, cylinder liner deformation primary evaluation, vibration intensity evaluation, cylinder gasket sealing evaluation, and piston ring and cylinder liner lubrication primary evaluation. The framework for the primary evaluation of the engine block and cylinder head assembly structure is as follows: Figure 5 As shown.

[0045] The overall coordination evaluation factor for the first-level evaluation of the engine block and cylinder head assembly structure is defined as follows: (3) In the formula, As the intensity coordination factor,

[0046] Let be the fatigue safety factor of the i-th component. This is the fatigue safety factor limit value for the i-th component. and The weights are respectively the basic strength requirements and the equal life design components.

[0047] Cylinder liner deformation first-level coordination factor,

[0048] Fourier transform of cylinder liners Deformation amplitude, This is the maximum value, which is the limit value for the deformation amplitude of this order. This is the optimal or minimum value of the deformation amplitude for this order.

[0049] Vibration intensity coordination factor

[0050] , and These represent the vibration intensity specified in the national standard for composite structures, the upper limit of vibration intensity, and the optimal value of vibration intensity.

[0051] Cylinder head gasket seal coordination factor,

[0052] This is the maximum contact pressure of the cylinder head gasket; This is the minimum contact pressure of the cylinder head gasket. The yield strength of the cylinder head gasket material. This represents the highest value of the gas explosion pressure.

[0053] Piston ring and cylinder liner primary coordination factor.

[0054] Minimum oil film thickness, This is the sum of the roughness of the bearing bush and the journal. and This refers to the peak oil film pressure and its limit value. and These are the weighting coefficients for lubrication condition and peak oil film pressure, respectively.

[0055] , , , and The weighting coefficients are shown in Table 3.

[0056] Table 3 Weights of Sub-objectives for Primary Evaluation of Engine Block and Cylinder Head

[0057] Representing multiple coordination factor values ​​on a radar chart can provide some direction and ideas for improving the design, such as... Figure 6 As shown.

[0058] The secondary evaluation of the engine block and cylinder head assembly structure comprises six parts: cylinder liner deformation secondary evaluation, sealing evaluation, vibration evaluation, piston ring and cylinder liner lubrication secondary evaluation, piston ring and cylinder liner wear evaluation, and weight reduction evaluation. The framework for the secondary evaluation of the engine block and cylinder head assembly structure is as follows: Figure 7 As shown.

[0059] The overall coordination evaluation factor for the secondary evaluation of the engine block and cylinder head assembly structure is defined as follows: (4) In the formula, The cylinder liner deformation secondary coordination factor,

[0060] Fourier transform of cylinder liners Deformation amplitude, This is the maximum value, which is the limit value for the deformation amplitude of this order. This is the optimal or minimum value of the deformation amplitude for this order. and These are the weighting coefficients.

[0061] Sealing coordination factor,

[0062] It refers to the piston ring leakage rate. It is its limit value, that is, its maximum value. The minimum leakage rate is the optimal value. This is the maximum contact pressure of the cylinder head gasket; This is the minimum contact pressure of the cylinder head gasket. The yield strength of the cylinder head gasket material. This represents the highest value of the gas explosion pressure. and These are the weighting coefficients for cylinder head gasket seal and piston ring seal, respectively.

[0063] Vibration intensity coordination factor

[0064] These are the index factors for the natural frequency component, the vibration component at weak and easily failed locations in the cylinder head, and the explosion pressure excitation component. These are the corresponding weighting coefficients.

[0065] Piston ring and cylinder liner secondary coordination factor

[0066] This represents the average value of the peak oil film pressure. This represents the maximum limit of the average peak pressure of the oil film. The minimum value of the average peak pressure of the oil film is the optimal value. The total frictional loss power consumption per cycle of the friction pair This is the limit value for power consumption due to friction loss. It is the minimum value of frictional power loss. , and These are their respective weighting coefficients.

[0067] Piston ring and cylinder liner wear compatibility factor

[0068] and These represent the wear rate of the friction pair per unit time during the break-in period and the steady-state period, respectively. and Each of them represents its limit value. and Each of them represents its optimal value. and These are their respective weighting coefficients.

[0069] Lightweight coordination factor,

[0070] For the first The quality of each component The mass limits for each component, The minimum value for each component is the optimal value.

[0071] , , , , and The weighting coefficients are shown in Table 4.

[0072] Table 4 Weights of Sub-objectives in the Secondary Evaluation of Engine Block and Cylinder Head

[0073] Representing multiple coordination factor values ​​on a radar chart can provide direction and ideas for the improved design of an engine, such as... Figure 8 As shown.

[0074] This invention proposes a hierarchical evaluation method for the coordination of engine assembly structures. Coordination refers to the various relationships among the subsystems and constituent elements of the overall system, such as cooperation, complementarity, and synchronization, and the comprehensive results and state of the system as a result of these relationships. There may be contradictions and conflicts between subsystems and constituent elements. By improving the design of each subsystem's constituent elements to eliminate and mitigate these conflicts, the system's coordinated balance is maintained, thereby improving overall system performance. Maximizing the function of each subsystem is the coordination optimization or coordination design process. Coordination evaluation targets complex systems, conducting qualitative and quantitative evaluation and analysis of their multi-faceted responses or constituent elements to achieve the overall optimal goal. Coordination requires clearly defining the evaluation methods for each sub-objective, rationally selecting evaluation indicators, formulating evaluation methods based on principles of simplicity and quantifiability, and establishing a mathematical calculation model for the quantitative hierarchical evaluation of each sub-objective. The above constitutes the establishment of the evaluation criteria layer for the coordination system.

[0075] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for graded evaluation of the coordination of engine assembly structures, characterized in that: The engine assembly structure consists of two parts: the crankshaft and the engine block assembly structure and the cylinder head assembly structure. Each part is divided into two levels of evaluation, with the coordination evaluation factor ranging from 0 to 1, where 1 represents the best and 0 represents the worst. The overall coordination evaluation factor for the first-level evaluation of the engine block and cylinder head assembly structure is defined as follows: In the formula, As the intensity coordination factor, Let be the fatigue safety factor of the i-th component. Let i be the fatigue safety factor limit value for the i-th component. and The weights for the impact of basic strength requirements and equal life design are respectively: Cylinder liner deformation first-level coordination factor, Fourier transform of cylinder liners Deformation amplitude, This is the maximum value, which is the limit for the deformation amplitude of this order. This represents the optimal or minimum value of the deformation amplitude for this order. Vibration intensity compatibility factor , and These are the vibration intensity specified in the national standard for composite structures, the upper limit of vibration intensity, and the optimal value of vibration intensity, respectively. Cylinder head gasket seal coordination factor, This is the maximum contact pressure of the cylinder head gasket. This is the minimum contact pressure of the cylinder head gasket. The yield strength of the cylinder head gasket material. This represents the highest value of the gas combustion pressure. Piston ring and cylinder liner primary coordination factor. Minimum oil film thickness, This is the sum of the roughness of the bearing bush and the journal. and For peak oil film pressure and its limit value; and These are the weighting coefficients for lubrication condition and peak oil film pressure, respectively. , , , and These are the weighting coefficients corresponding to each coordinating factor.

2. The method for graded evaluation of engine assembly structure coordination according to claim 1, characterized in that: The overall coordination evaluation factor for the primary evaluation of the crankshaft and engine block assembly structure is defined as follows: In the formula, As the intensity coordination factor, Let be the fatigue safety factor of the i-th component. This is the fatigue safety factor limit value for the i-th component; and The weights for the impact of basic strength requirements and equal life design are respectively: The first-order compatibility factor for main bearing bore deformation. The maximum out-of-roundness of the main bearing section; The limit value for the out-of-roundness of the main bearing section. Minimum out-of-roundness of the main bearing section; Vibration intensity compatibility factor , and These are the vibration intensity, upper limit, and optimal value specified in the national standard for composite structures, respectively. This is the crankshaft torsional vibration coordination factor; Primary coordination factor for main bearing lubrication; Minimum oil film thickness, This is the sum of the roughness of the bearing bush and the journal. and For peak oil film pressure and its limit value; and These are the weighting coefficients for lubrication condition and peak oil film pressure, respectively. , , , and This represents the weighting coefficient of the coordination factor.

3. The method for graded evaluation of engine assembly structure coordination according to claim 1, characterized in that: The primary evaluation of the crankshaft housing structure includes five parts: strength compatibility evaluation, primary evaluation of main bearing bore deformation, vibration intensity evaluation, crankshaft torsional vibration evaluation, and primary evaluation of main bearing lubrication.

4. The method for graded evaluation of engine assembly structure coordination according to claim 3, characterized in that: The secondary evaluation of the crankshaft housing assembly structure includes the evaluation of the vibration compatibility of the assembly structure, the secondary evaluation of the deformation compatibility of the main bearing bore, the secondary evaluation of the lubrication compatibility of the main bearing, the evaluation of the wear compatibility of the main bearing, and the evaluation of the lightweight compatibility.

5. The method for graded evaluation of engine assembly structure coordination according to claim 1, characterized in that: The first-level evaluation of the engine block and cylinder head assembly structure includes five parts: strength compatibility evaluation, cylinder liner deformation first-level evaluation, vibration intensity evaluation, cylinder gasket sealing evaluation, and piston ring and cylinder liner lubrication first-level evaluation.

6. The method for graded evaluation of engine assembly structure coordination according to claim 1, characterized in that: The secondary evaluation of the engine block and cylinder head assembly structure includes six parts: secondary evaluation of cylinder liner deformation, sealing evaluation, vibration evaluation, secondary evaluation of piston ring and cylinder liner lubrication, evaluation of piston ring and cylinder liner wear, and lightweight evaluation.

7. The method for graded evaluation of engine assembly structure coordination according to claim 1, characterized in that: By representing multiple coordination factor values ​​on a radar chart, the reliability level of the analyzed object in various aspects can be obtained. Since each coordination factor is between 0 and 1, with 1 representing the best and 0 representing the worst, the relationship between the magnitudes of each coordination factor can be qualitatively characterized in the radar chart.

8. The method for graded evaluation of engine assembly structure coordination according to claim 1, characterized in that: The overall coordination evaluation factor for the secondary evaluation of the engine block and cylinder head assembly structure is defined as follows: In the formula, The cylinder liner deformation secondary coordination factor, Fourier transform of cylinder liners Deformation amplitude, This is the maximum value, which is the limit for the deformation amplitude of this order. This represents the optimal or minimum value of the deformation amplitude for this order. and These are the weighting coefficients; Sealing coordination factor, It refers to the piston ring leakage rate. It is its limit value, that is, its maximum value. The minimum leakage rate is the optimal value. This is the maximum contact pressure of the cylinder head gasket. This is the minimum contact pressure of the cylinder head gasket. The yield strength of the cylinder head gasket material. This represents the highest value of the gas combustion pressure. and These are the weighting coefficients for cylinder head gasket seal and piston ring seal, respectively. Vibration intensity coordination factor These are the index factors for the natural frequency component, the vibration component at weak and easily failed locations in the cylinder head, and the explosion pressure excitation component. These are the corresponding weighting coefficients; Piston ring and cylinder liner secondary coordination factor This represents the average value of the peak oil film pressure. This represents the maximum limit of the average peak pressure of the oil film. The minimum average value of the peak oil film pressure is the optimal value. The total frictional loss power consumption per cycle of the friction pair This is the limit value for power consumption due to friction loss. It is the minimum value of frictional power loss; , and These are their respective weighting coefficients; Piston ring and cylinder liner wear compatibility factor and These represent the wear rate of the friction pair per unit time during the break-in period and the steady-state period, respectively. and Each of them represents its limit value. and Each of them represents its optimal value. and These are their respective weighting coefficients; Lightweight coordination factor, For the first The quality of each component The mass limits for each component, The minimum value for each component is the optimal value. , , , , and These are the weighting coefficients corresponding to each coordinating factor.

9. The method for graded evaluation of engine assembly structure coordination according to claim 1, characterized in that: The overall coordination evaluation factor for the secondary evaluation of the crankshaft and engine block assembly structure is defined as follows: （2） In the formula, For the vibration compatibility factor of the composite structure, Secondary compatibility factor for main bearing bore deformation. Secondary coordination factor for main bearing lubrication. Main bearing wear compatibility factor Lightweight coordination factor; , , , and This represents the weighting coefficient of the coordination factor.

Images