CN115758570A - Engine composite structure coordination grading evaluation method - Google Patents
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Abstract
The invention relates to a grading evaluation method for coordination of an engine composite structure, wherein the engine composite structure comprises a crankshaft engine body composite structure and an engine body cylinder cover composite structure, each part is divided into two grades of evaluation, the coordination evaluation factor is between 0 and 1, 1 represents the best, and 0 represents the worst. The invention adopts harmony grading evaluation, wherein the first-level evaluation corresponds to a concept design stage, and the second-level evaluation corresponds to a scheme design stage. The first-level evaluation can quickly reflect factors such as rigidity, strength, vibration, lubrication, sealing and the like of the engine combined structure, and provides a basis for the arrangement of the overall scheme; after entering a scheme design stage, along with the improvement of the maturity of the model, the influence of a detailed structure on rigidity, vibration and lubrication and the influence of abrasion, sealing, light weight and the like need to be considered, and the weak link of the engine combined structure can be accurately found by applying secondary rating, and a direction and a basis are provided for the improvement of the structure.
Description
Technical Field
The invention belongs to the technical field of engines, and particularly relates to a grading evaluation method for coordination of an engine combination structure.
Background
The mechanical structure is continuously developed to be complicated along with the improvement of scientific and technical and functional requirements, the requirements for multi-structure and multi-disciplinary collaborative design are continuously improved in the whole system design process, and the current serial structure design method gradually does not meet the overall design requirements. Meanwhile, along with the continuous improvement of the power density, light weight and energy conservation and emission reduction requirements of the internal combustion engine, various loads of the crankshaft engine body combined structure and the engine body cylinder cover combined structure are obviously increased, and the challenges on the aspects of the reliability of the whole engine and the like are provided. In order to face the challenges, a coordinated matching overall evaluation index system analysis research is developed on the main load combined structure of the diesel engine so as to construct a multi-level and multi-index collaborative evaluation framework system.
In the traditional research and development process, only single factors can be analyzed and evaluated, and the requirement of multi-target evaluation research and development cannot be met. Such as the difficulty of gas seal design under high thermal mechanical loads. The pretightening force of the bolt of the cylinder cover is increased, the sealing pressure is increased, the sealing performance is improved, but the deformation of the cylinder sleeve is increased, the fatigue safety coefficient of the structural part is reduced, therefore, the deformation of the combined structure is coordinated by coordinating the load arrangement and distribution of the cylinder cover bolts and the size and shape of key parts, and meanwhile, the requirements of multiple targets such as gas sealing of a cylinder gasket, deformation of a cylinder sleeve, structural fatigue strength and the like are met. The same specifications and standards are applied at different design stages, and different analysis and evaluation standards have large difference and lack a uniform evaluation system. For example, vibration analysis evaluation is performed in a concept design stage and a scheme design stage, while vibration intensity evaluation is performed in two stages of a traditional research and development process by using the same standard, and if the vibration intensity exceeds the standard, an optimization direction cannot be given.
Disclosure of Invention
In order to solve the technical problems, the invention provides a grading evaluation method for the coordination of an engine combined structure, which solves the defects of the prior art.
The technical scheme of the invention is as follows: a grading evaluation method for coordination of an engine combined structure is characterized by comprising the following steps: the engine combination structure comprises a crankshaft engine body combination structure and an engine body cylinder cover combination structure, each part is divided into two stages of evaluation, the coordinated evaluation factor is between 0 and 1, 1 represents the best, and 0 represents the worst.
The primary evaluation of the crankshaft body combined structure comprises five parts, namely strength coordination evaluation, primary evaluation of main bearing hole deformation, vibration intensity evaluation, crankshaft torsional vibration evaluation and primary evaluation of main bearing lubrication.
The secondary evaluation of the combined structure of the crankshaft body comprises five parts, namely vibration coordination evaluation of the combined structure, secondary coordination evaluation of deformation of a main bearing hole, vibration intensity coordination evaluation, secondary coordination evaluation of main bearing lubrication, wear coordination evaluation of a main bearing and lightweight coordination evaluation.
The first-level evaluation of the combined structure of the engine body and the cylinder cover comprises five parts, namely strength coordination evaluation, first-level evaluation of cylinder sleeve deformation, vibration intensity evaluation, cylinder gasket sealing evaluation and first-level evaluation of lubrication of a piston ring and a cylinder sleeve.
The secondary evaluation of the combined structure of the engine body and the cylinder cover comprises six parts, namely secondary evaluation of cylinder sleeve deformation, sealing evaluation, vibration evaluation, secondary evaluation of piston ring and cylinder sleeve lubrication, wear evaluation of the piston ring and cylinder sleeve and lightweight evaluation.
Has the advantages that: the invention adopts harmony grading evaluation, wherein the first-level evaluation corresponds to a concept design stage, and the second-level evaluation corresponds to a scheme design stage. Because the model maturity in the concept design stage is low, the analysis boundary conditions are less, the first-level evaluation can quickly reflect factors such as rigidity, strength, vibration, lubrication, sealing and the like of the engine combined structure, and provides a basis for the arrangement of the overall scheme; after entering a scheme design stage, along with the improvement of the maturity of the model, the influence of a detailed structure on rigidity, vibration and lubrication and the influence of abrasion, sealing, light weight and the like need to be considered, and the weak link of the engine combined structure can be accurately found by applying secondary rating, and a direction and a basis are provided for the improvement of the structure.
Drawings
FIG. 1 first-level evaluation frame diagram of crankshaft engine block composite structure
FIG. 2 first-level evaluation radar chart of crankshaft engine body combined structure
FIG. 3 is a two-level evaluation frame diagram of the crankshaft body combined structure
FIG. 4 radar chart for two-stage evaluation of crankshaft body composite structure
FIG. 5 first-level evaluation frame diagram of combined structure of engine body and cylinder cover
FIG. 6 first-level evaluation radar chart of engine body and cylinder cover combined structure
FIG. 7 two-level evaluation frame diagram of combined structure of engine body and cylinder cover
FIG. 8 is a radar chart for two-stage evaluation of a combined structure of a machine body and a cylinder cover.
Detailed Description
To make the objects, content and advantages of the present invention clearer, the following further describes in detail embodiments of the present invention.
The invention provides a grading evaluation method for coordination of an engine combined structure. Each part was divided into two levels of evaluation. The coordination evaluation factor is between 0 and 1, with 1 being the best and 0 being the worst. The first-level evaluation is applied to quickly reflect factors such as rigidity, strength, vibration, lubrication, sealing and the like of the engine combined structure, and provide basis for the arrangement of the overall scheme; the weak link of the engine combined structure can be accurately found by applying the secondary rating, and a direction and a basis are provided for the improvement of the structure.
The primary evaluation of the crankshaft body combined structure comprises five parts, namely strength coordination evaluation, primary evaluation of main bearing hole deformation, vibration intensity evaluation, crankshaft torsional vibration evaluation and primary evaluation of main bearing lubrication, wherein the primary evaluation of the crankshaft body combined structure is carried out, and an evaluation framework is shown in figure 1.
The primary evaluation total coordination evaluation factor of the crankshaft engine body combined structure is defined as follows:
Λ=Λ 1 *γ 1 +Λ 2 *γ 2 +Λ 3 *γ 3 +Λ 4 *γ 4 +Λ 5 *γ 5 (1)
in the formula, Λ 1 In order to be the intensity co-ordination factor,
ε i fatigue safety factor of i-th part, epsilon i,li And the fatigue safety coefficient limit value of the ith component is set. Alpha and beta are respectively the influence weight of the basic requirement of strength and the equal life design part.
Λ 2 Is a primary coordination factor for the deformation of the main bearing hole,
r is the maximum value of the out-of-roundness of the section of the main bearing; r is li Is a limit value of the out-of-roundness of the main bearing section, r min The minimum value of the out-of-roundness of the section of the main bearing.
Λ 3 A coordination factor of the vibration intensity is determined,
V s ,V s,li and V s,min The vibration intensity, the upper limit value of the vibration intensity and the optimal value of the vibration intensity are respectively specified for the national standard of the composite structure.
Λ 4 A coordination factor of the torsional vibration of the crankshaft,
α c ,α c,li and alpha c,min Respectively representing a crankshaft torsion angle displacement value, a limit value and an optimal value; sigma t ,σ t,li And σ t,min The maximum value, the limited value and the optimal value of the torsional stress of the crankshaft are respectively. Alpha and beta are the torsional angular displacement and torsional stress weight, respectively.
Λ 5 And lubricating a primary coordination factor of the main bearing.
h min Is the minimum oil film thickness, ra is the sum of the roughness of the bearing bush and the journal, P a And P a,li The peak oil film pressure and its limit. Alpha and beta are the lubrication state and the peak oil film pressure weight coefficient respectively.
TABLE 1 sub-target weight for first-level evaluation of crankshaft body
The method has the advantages that multiple coordination factor values are represented in the radar map, reliability levels of all aspects of an analyzed object can be rapidly and visually obtained, and since the coordination factors are all between 0 and 1, 1 represents the best, and 0 represents the worst, the magnitude relation among the coordination factors can be qualitatively represented in the radar map, so that the reliability design of the combination structure in which the aspects are poor and which the aspects are good can be rapidly known, and whether multiple coordination factors are too different or not can be rapidly known. A certain direction of thought can be provided for subsequent improved design, as shown in fig. 2.
The secondary evaluation of the combined structure of the crankshaft body comprises five parts, namely combined structure vibration coordination evaluation, primary bearing hole deformation secondary coordination evaluation, vibration intensity coordination evaluation, primary bearing lubrication secondary coordination evaluation, primary bearing wear coordination evaluation and lightweight coordination evaluation. The composite structure secondary evaluation framework is shown in fig. 3.
The general coordination evaluation factor of the secondary evaluation of the crankshaft body combined structure is defined as follows:
in the formula, Ψ 1 In order to coordinate the factors for the vibration of the composite structure,
C f 、C c 、C b index factors of a natural frequency part, a crankshaft vibration part and a cylinder vibration part are respectively, and alpha, beta and gamma are corresponding weight coefficients.
Ψ 2 A secondary coordination factor of the deformation of the main bearing hole,
r, z and d are respectively the maximum value of out-of-roundness of the main bearing section, the coaxiality difference of bearing bushes of a main bearing journal and the average value of the total bearing offset; r is li 、z ly And d li Respectively are the limit values of the three; r is min 、z min And d min The values are the minimum values which are the optimal values of the three.
Ψ 3 A two-stage coordination factor for lubricating the main bearing,
P a is the average value of the peak oil film pressure of the bearing, P a,li Maximum limit of the mean value of the peak pressure of the oil film, P a,min The minimum value of the oil film peak pressure average value is the optimal value. L is a For total friction loss power consumption per cycle of friction pair, L a,li Is a friction loss power consumption limit value, L a,min Is the minimum value of the frictional loss power. α, β, γ, and δ are index weight influence coefficients.
Ψ 4 The main bearing wear coordination factor is a factor of the main bearing wear coordination,
L m1 and L m2 The unit time abrasion loss of the friction pair in the running-in period and the steady state period, L m1,li And L m2,li Respectively is a limit value of L m1,min And L m2,min Respectively, their optimal values, and alpha and beta, respectively, their weights.
Ψ 5 And (4) a light weight coordination factor.
m i Is the ith part mass, m i,li For mass limit values of the components, m i,min The minimum value of each part is the optimal value.
TABLE 2 sub-target weight for two-stage evaluation of crankshaft engine
Representing multiple co-ordination factor values in a radar map may provide a directional idea for improved design, as shown in FIG. 4.
The first-level evaluation of the combined structure of the engine body and the cylinder cover comprises five parts, namely strength coordination evaluation, cylinder sleeve deformation first-level evaluation, vibration intensity evaluation, cylinder gasket sealing evaluation and piston ring and cylinder sleeve lubrication first-level evaluation, and a first-level evaluation frame of the combined structure of the engine body and the cylinder cover is shown in figure 5.
The first-level evaluation total coordination evaluation factor of the engine body cylinder cover composite structure is defined as follows:
Γ=Γ 1 *ω 1 +Γ 2 *ω 2 +Γ 3 *ω 3 +Γ 4 *ω 4 +Γ 5 *ω 5 (3)
in the formula, gamma 1 In order to be a strength-coordinating factor,
ε i fatigue safety factor of i-th part, epsilon i,li And limiting the fatigue safety factor of the ith component. Alpha and beta are respectively the influence weight of the basic requirement of strength and the equal life design part.
Γ 2 The cylinder sleeve is deformed by a first-level coordination factor,
Δu i is the i-th order Fourier deformation amplitude, delta u, of the cylinder liner i.li For a limit value, i.e. maximum value, of the deformation amplitude of this order, deltau i.min The optimal value of the deformation amplitude of this order, i.e. the minimum value.
Γ 3 A vibration intensity co-ordination factor is used,
V s ,V s,li and V s,min The vibration intensity, the upper limit value of the vibration intensity and the optimal value of the vibration intensity are respectively specified for the national standard of the composite structure.
Γ 4 Cylinder gasketA sealing coordination factor is set for the sealing of the pipe,
σ pmax the maximum contact pressure of the cylinder gasket; sigma pmin Minimum contact pressure, σ, of the cylinder head gasket b Is the yield strength, P, of the cylinder liner material f The highest value of the gas explosion pressure.
Γ 5 A primary coordination factor of the piston ring and the cylinder sleeve,
h min is the minimum oil film thickness, ra is the sum of the roughness of the bearing bush and the journal, P a And P a,li Peak oil film pressure and its limit. Alpha and beta are the lubrication state and peak oil film pressure weighting coefficients, respectively.
ω 1 、ω 1 、ω 2 、ω 3 、ω 4 And ω 5 Are the weighting coefficients, as shown in table 3.
TABLE 3 sub-target weight for first-class evaluation of engine cylinder head
Coordination factor name | Weight of co-ordination factor omega j |
Intensity coordination evaluation factor gamma 1 | 0.2640 |
First-order evaluation factor gamma for cylinder sleeve deformation 2 | 0.3960 |
Vibration intensity evaluation factor gamma 3 | 0.1650 |
Cylinder gasket seal evaluation factor gamma 4 | 0.1221 |
First-level evaluation factor gamma for lubrication of piston ring cylinder sleeve 5 | 0.0529 |
Representing multiple co-ordination factor values in a radar map may provide a directional idea for improved design, as shown in FIG. 6.
The secondary evaluation of the combined structure of the engine body and the cylinder cover comprises six parts, namely secondary evaluation of cylinder sleeve deformation, sealing evaluation, vibration evaluation, secondary evaluation of piston ring and cylinder sleeve lubrication, wear evaluation of the piston ring and the cylinder sleeve and lightweight evaluation, and a secondary evaluation frame of the combined structure of the engine body and the cylinder cover is shown in figure 7.
The total coordinated evaluation factor of the two-stage evaluation of the combined structure of the engine body and the cylinder cover is defined as follows:
Φ=Φ 1 *ω 1 +Φ 2 *ω 2 +Φ 3 *ω 3 +Φ 4 *ω 4 +Φ 5 *ω 5 +Φ 6 *ω 6 + (4)
in the formula phi 1 Is a secondary coordination factor for the deformation of the cylinder sleeve,
Δu i is the i-th order Fourier deformation amplitude, delta u, of the cylinder liner i.li For a limit value, i.e. maximum value, of the deformation amplitude of this order, deltau i.min The optimal value of the deformation amplitude of this order, i.e. the minimum value. α and β are weight coefficients, respectively.
Φ 2 Sealing coordinationThe factor(s) is (are),
L all is the leakage of piston ring, L all,li Is its limit value, i.e. maximum value, L all,min The minimum value of the air leakage is the optimal value. Sigma pmax The maximum contact pressure of the cylinder gasket; sigma pmin Minimum contact pressure, σ, of the cylinder head gasket b Is the yield strength, P, of the cylinder liner material f The highest value of the gas explosion pressure. Alpha and beta are the cylinder gasket seal and piston ring seal weight coefficients, respectively.
Φ 3 A coordination factor of the vibration intensity is determined,
B f 、B c 、B p the characteristic factors are respectively a natural frequency part, a cylinder cover weak volatile position vibration part and an explosion pressure excitation part, and alpha, beta and gamma are corresponding weight coefficients.
Φ 4 A secondary coordination factor of a piston ring and a cylinder sleeve,
P a is the average value of the peak oil film pressure, P a,li Maximum limit of the oil film peak pressure mean value, P a,min The minimum value of the oil film peak pressure average value is the optimal value. L is a Total friction loss power per cycle for the friction pair, L a,li Is a friction loss power consumption limit value, L a,min Is the minimum value of the frictional loss power. α, β, and γ are their weight coefficients, respectively.
Φ 5 The wear coordination factor of the piston ring and the cylinder sleeve,
L m1 and L m2 The unit time abrasion loss of the friction pair in the running-in period and the steady state period, L m1,li And L m2,li Respectively, is a limit value, L m1,min And L m2,min Respectively, their optimal values, and alpha and beta, respectively, their weighting coefficients.
Φ 6 The light-weight coordination factor is obtained by the following steps,
m i is the ith part mass, m i,li For mass limit values of the components, m i,min The minimum value of each part is the optimal value.
ω 1 、ω 2 、ω 3 、ω 4 、ω 5 And ω 6 Are the weighting coefficients, as shown in table 4.
TABLE 4 sub-target weight for two-stage evaluation of engine block and cylinder head
Coordination factor name | Weight of co-ordination factor omega j |
Cylinder sleeve deformation coordination factor phi 1 | 0.3750 |
Composite structure sealing coordination factor phi 2 | 0.2812 |
Combined structure vibration coordination factor phi 3 | 0.1563 |
Piston ring cylinder sleeve lubrication coordination factor phi 4 | 0.0719 |
Piston ring and cylinder sleeve wear coordination factor phi 5 | 0.0219 |
Light weight coordination factor phi 6 | 0.0937 |
Representing multiple co-ordination factor values in a radar map may provide directions and ideas for improved design of an engine, as shown in figure 8.
The coordination of the hierarchical evaluation method for the coordination of the engine combination structure provided by the invention refers to the fact that subsystems and constituent elements of a total system have various association relations such as cooperation, complementation and synchronization, and the comprehensive results and states presented by the system are caused by the relations. The system coordination balance relationship is maintained by eliminating and relieving conflicts through improving the design of the components of each subsystem, so that the overall performance of the system is improved, and the maximum function of each subsystem is the coordination optimization or coordination design process. And the coordinated evaluation aims at the complex system, and qualitatively and quantitatively evaluates and analyzes the multi-aspect response or the constituent elements of the complex system so as to achieve the overall optimal target. The coordination needs to make clear the evaluation method of each sub-target, reasonably selects the evaluation index, formulates the evaluation method based on the principles of conciseness, quantization and the like, establishes a mathematical calculation model of quantitative and graded evaluation of each sub-target, and establishes an evaluation criterion layer of a coordination system.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.
Claims (10)
1. A grading evaluation method for coordination of an engine combined structure is characterized by comprising the following steps: the engine combination structure comprises a crankshaft engine body combination structure and an engine body cylinder cover combination structure, each part is divided into two stages of evaluation, the coordinated evaluation factor is between 0 and 1, 1 represents the best, and 0 represents the worst.
2. The engine composite structure coordination grading evaluation method according to claim 1, characterized in that: the primary evaluation of the crankshaft body combined structure comprises five parts, namely strength coordination evaluation, primary evaluation of main bearing hole deformation, vibration intensity evaluation, crankshaft torsional vibration evaluation and primary evaluation of main bearing lubrication.
3. The grading evaluation method for the coordination of the engine combination structure according to claim 2, characterized in that: the secondary evaluation of the combined structure of the crankshaft body comprises five parts, namely combined structure vibration coordination evaluation, primary bearing hole deformation secondary coordination evaluation, vibration intensity coordination evaluation, primary bearing lubrication secondary coordination evaluation, primary bearing wear coordination evaluation and lightweight coordination evaluation.
4. The grading evaluation method for the coordination of the engine combination structure according to claim 1, characterized in that: the first-level evaluation of the combined structure of the engine body and the cylinder cover comprises five parts, namely strength coordination evaluation, first-level evaluation of cylinder sleeve deformation, vibration intensity evaluation, cylinder gasket sealing evaluation and first-level evaluation of piston ring and cylinder sleeve lubrication.
5. The engine composite structure coordination grading evaluation method according to claim 1, characterized in that: the secondary evaluation of the combined structure of the engine body and the cylinder cover comprises six parts, namely secondary evaluation of cylinder sleeve deformation, sealing evaluation, vibration evaluation, secondary evaluation of piston ring and cylinder sleeve lubrication, wear evaluation of the piston ring and cylinder sleeve and lightweight evaluation.
6. The engine composite structure coordination grading evaluation method according to claim 1, characterized in that: the primary evaluation total coordination evaluation factor of the crankshaft engine body combined structure is defined as follows:
Λ=Λ 1 *γ 1 +Λ 2 *γ 2 +Λ 3 *γ 3 +Λ 4 *γ 4 +Λ s *γ 5 (1)
in the formula, Λ 1 In order to be the intensity co-ordination factor,
ε i fatigue safety factor of i-th part, epsilon i,li The fatigue safety coefficient limiting value of the ith component is set; alpha and beta are respectively the influence weight of the basic requirement of strength and the equal life design part;
Λ 2 is a primary coordination factor for the deformation of the main bearing hole,
r is the maximum value of the out-of-roundness of the section of the main bearing; r is li Is a limit value of the out-of-roundness of the main bearing section, r min The minimum value of the out-of-roundness of the section of the main bearing is obtained;
Λ 3 a vibration intensity co-ordination factor is used,
V s ,V s,li and V s,min The vibration intensity, the upper limit value of the vibration intensity and the optimal value of the vibration intensity are respectively specified for the national standard of the composite structure;
Λ 4 a coordination factor of the torsional vibration of the crankshaft,
α c ,α c,li and alpha c,min Respectively representing a crankshaft torsion angle displacement value, a limit value and an optimal value; sigma t ,σ t,li And σ t,min Respectively taking the maximum value, the limited value and the optimal value of the torsional stress of the crankshaft; alpha and beta are torsion angular displacement and torsion stress weight respectively;
Λ 5 lubricating a primary coordination factor of the main bearing;
h min is the minimum oil film thickness, ra is the sum of the roughness of the bearing bush and the journal, P a And P a,li Peak oil film pressure and its limit; alpha and beta are respectively a lubricating state and a peak oil film pressure weight coefficient; gamma ray 1 、γ 2 、γ 3 、γ 4 And gamma 5 Is the co-ordination factor weight coefficient.
7. The grading evaluation method for the coordination of the engine combination structure according to claim 1, characterized in that: the general coordination evaluation factor of the secondary evaluation of the crankshaft body combined structure is defined as follows:
Ψ=Ψ 1 *γ 1 +Ψ 2 *Υ 2 +Ψ 3 *γ 3 +Ψ 4 *Υ 4 +Ψ 3 *γ 5 (2)
in the formula, psi 1 In order to coordinate the factors for the vibration of the composite structure,
C f 、C c 、C b index factors of a natural frequency part, a crankshaft vibration part and a cylinder vibration part are respectively, and alpha, beta and gamma are corresponding weight coefficients;
Ψ 2 main shaftThe deformation of the bearing hole is a secondary coordination factor,
r, z and d are respectively the maximum value of out-of-roundness of the main bearing section, the coaxiality difference of bearing bushes of a main bearing journal and the average value of the total bearing offset; r is a radical of hydrogen li 、z li And d li Respectively are the limit values of the three; r is min 、z min And d min The three values are respectively the optimal value, namely the minimum value;
Ψ 3 the main bearing is lubricated by a secondary coordination factor,
P a is the average value of the bearing peak oil film pressure, P a,li Maximum limit of the oil film peak pressure mean value, P a,mmin The minimum value of the oil film peak pressure average value is an optimal value; l is a radical of an alcohol a For total friction loss power consumption per cycle of friction pair, L a,li Is a friction loss power consumption limit value, L a,min Is the minimum value of the frictional loss power; alpha, beta, gamma and delta are each index weight influence coefficient;
Ψ 4 the main bearing wear coordination factor is a factor of the main bearing wear coordination,
L m1 and L m2 The unit time abrasion loss of the friction pair in the running-in period and the steady state period, L m1,li And L m2,li Respectively is a limit value of L m1,min And L m2,min Respectively, the optimal values, and alpha and beta respectively are the weights;
Ψ 5 a lightweight coordination factor;
m i is the ith part mass, m i,li For each part mass limit value, m i,min The minimum value of each component is the optimal value;
γ 1 、γ 2 、γ 3 、γ 4 and gamma 5 Is the co-ordination factor weight coefficient.
8. The grading evaluation method for the coordination of the engine combination structure according to claim 1, characterized in that: the first-level evaluation total coordination evaluation factor of the combined structure of the engine body and the cylinder cover is defined as follows:
Γ=Γ 1 *ω 1 +Γ 2 *ω 2 +Γ 3 *ω 3 +Γ 4 *ω 4 +Γ 5 *ω 5 (3)
in the formula, gamma 1 In order to be a strength-coordinating factor,
ε i fatigue safety factor of i-th part, epsilon i,li And the fatigue safety coefficient limit value of the ith component is set. Alpha and beta are respectively the influence weight of the basic requirement of strength and the equal life design part.
Γ 2 The cylinder sleeve is deformed by a first-level coordination factor,
Δu i is the i-th Fourier deformation amplitude, deltau, of the cylinder liner i,li For a limit value, i.e. maximum value, of the deformation amplitude of this order, deltau i.min The optimal value of the deformation amplitude of this order, i.e. the minimum value.
Γ 3 A vibration intensity co-ordination factor is used,
V s ,V s,li and V s,min The vibration intensity, the upper limit value of the vibration intensity and the optimal value of the vibration intensity are respectively specified for the national standard of the composite structure.
Γ 4 The sealing coordination factor of the cylinder gasket is obtained,
σ pmax the maximum contact pressure of the cylinder gasket; sigma pmin Minimum contact pressure, σ, of the cylinder head gasket b Is the yield strength, P, of the cylinder liner material f The highest value of the gas explosion pressure.
Γ 5 A primary coordination factor of the piston ring and the cylinder sleeve,
h min is the minimum oil film thickness, ra is the sum of the roughness of the bearing bush and the journal, P a And P a,li The peak oil film pressure and its limit. Alpha and beta are the lubrication state and the peak oil film pressure weight coefficient respectively.
ω 1 、ω 2 、ω 3 、ω 4 And ω 5 And the weight coefficient corresponds to each coordination factor.
9. The grading evaluation method for the coordination of the engine combination structure according to claim 1, characterized in that: the secondary evaluation of the combined structure of the engine body and the cylinder cover comprises six parts, namely, secondary evaluation of cylinder sleeve deformation, sealing evaluation, vibration evaluation, secondary evaluation of lubrication of the piston ring and the cylinder sleeve, wear evaluation of the piston ring and the cylinder sleeve and lightweight evaluation, and a secondary evaluation frame of the combined structure of the engine body and the cylinder cover is shown in figure 7.
The total coordinated evaluation factor of the two-stage evaluation of the combined structure of the engine body and the cylinder cover is defined as follows:
Φ=Φ 1 *ω 1 +Φ 2 *ω 2 +Φ 3 *ω 3 +Φ 4 *ω 4 +Φ 5 *ω 5 +Φ 6 *ω 6 (4)
in the formula phi 1 Is a secondary coordination factor for the deformation of the cylinder sleeve,
Δu i is the i-th order Fourier deformation amplitude, delta u, of the cylinder liner i.li For a limit value, i.e. maximum value, of the deformation amplitude of this order, deltau i.min The optimal value of the deformation amplitude of this order, i.e. the minimum value. α and β are weight coefficients, respectively.
Φ 2 A sealing coordination factor is set for the sealing of the pipe,
L all is the leakage of piston ring, L all,li Is its limit value, i.e. maximum value, L all,min The minimum value of the air leakage is the optimal value. Sigma pmax The maximum contact pressure of the cylinder gasket; sigma pmin Minimum contact pressure of cylinder head gasket, σ b Is the yield strength, P, of the cylinder liner material f The highest value of the gas explosion pressure. Alpha and beta are the cylinder gasket seal and piston ring seal weight coefficients, respectively.
Φ 3 A vibration intensity co-ordination factor is used,
B f 、B c 、B p index factors of a natural frequency part, a weak volatile position vibration part of a cylinder cover and an explosion pressure excitation part are respectively included, and alpha, beta and gamma are corresponding weight coefficients.
Φ 4 A secondary coordination factor of a piston ring and a cylinder sleeve,
P a is the average value of the peak oil film pressure, P a,li Maximum limit of the mean value of the peak pressure of the oil film, P a,min The minimum value of the oil film peak pressure average value is the optimal value. L is a For total friction loss power consumption per cycle of friction pair, L a,li Is a friction loss power consumption limit value, L a,min Is the minimum value of the frictional loss power. α, β, and γ are their weight coefficients, respectively.
Φ 5 The wear coordination factor of the piston ring cylinder sleeve,
L m1 and L m2 The unit time abrasion loss of the friction pair in the running-in period and the steady state period, L m1,li And L m2,li Respectively, is a limit value, L m1,min And L m2,min Respectively, their optimal values, and alpha and beta, respectively, their weighting coefficients.
Φ 6 The light-weight coordination factor is obtained by the following steps,
m i is the ith part mass, m i,li For each part mass limit value, m i,min The minimum value of each part is the optimal value.
ω 1 、ω 2 、ω 3 、ω 4 、ω 5 And ω 6 And the weight coefficient corresponds to each coordination factor.
10. The grading evaluation method for the coordination of the engine combination structure according to claim 1, characterized in that: and expressing a plurality of coordination factor values in a radar map to obtain the reliability level of each aspect of the analyzed object, wherein each coordination factor is between 0 and 1, 1 represents the best, and 0 represents the worst, so that the size relationship among the coordination factors can be qualitatively represented in the radar map.
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