Integrated simulation method based on whole cylinder cover manufacturing process

Abstract

The invention provides an integrated simulation method based on a whole cylinder cover manufacturing process, which comprises the following steps: designing a cylinder cover machining simulation model based on a cylinder cover product, complementing a part removed by machining, defining the model as different areas, and combining the different areas to construct a complete cylinder cover blank model. The change in the machining process is simulated; and according to the cylinder cover heat treatment simulation model, on the basis of the machining simulation model, partition processing is carried out according to boundary conditions of heat treatment, and the cylinder cover heat treatment simulation model is obtained. The integrated simulation method based on the whole cylinder cover manufacturing process comprises a casting process, a heat treatment process, a machining process and calculation analysis evaluation, and can be directly used for casting process simulation, heat treatment process simulation, machining process simulation, calculation analysis and product engineering drawing generation.

Description

Technical Field

[0001] The invention belongs to the field of simulation models, and in particular relates to an integrated simulation method based on the entire manufacturing process of a cylinder head. Background Art

[0002] The cylinder head is a key component in the internal combustion engine. Its manufacturing process usually includes three main steps: casting, heat treatment and machining. Due to the complex structure and uneven wall thickness of the cylinder head, it will be subjected to different degrees of thermal and mechanical loads at different manufacturing stages, which directly affects the residual stress and final performance of the cylinder head. Therefore, information transmission throughout the manufacturing process is crucial for the calculation and analysis of the cylinder head.

[0003] At present, existing technologies usually handle casting, heat treatment and machining processes separately, using different simulation models and software platforms for each stage, resulting in low efficiency of information transfer and prone to errors. For example, the blank model of the casting process needs to be modified and partitioned before heat treatment simulation, and the machining data also needs to be remapped for subsequent calculation and analysis. This method not only increases the workload, but may also affect the accuracy of the simulation results.

[0004] Although there are studies on CNC machining, mechanical processing technology design and casting process in the existing technical literature, these studies fail to cover the entire process of cylinder head manufacturing and fail to achieve unified management of simulation models and information. Therefore, it is of great significance to develop a simulation model that can uniformly manage the entire process of casting, heat treatment, mechanical processing and computational analysis. Summary of the invention

[0005] In view of this, the present invention aims to solve the problem of inconsistency between simulation models and information transmission in the prior art, and to provide an integrated simulation method based on the entire cylinder head manufacturing process. The model can efficiently and accurately transmit various types of information in the manufacturing process, thereby improving the accuracy of cylinder head calculation and analysis.

[0006] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] An integrated simulation method based on the entire cylinder head manufacturing process, including:

[0008] Simulation method of cylinder head machining simulation model: Based on the cylinder head product design model, the parts removed by machining are completed, and the model is defined as different areas. A complete cylinder head blank model is constructed by combining different areas, thereby simulating the changes in the machining process;

[0009] Simulation method of cylinder head heat treatment simulation model: Based on the machining simulation model, partition processing is performed according to the boundary conditions of heat treatment to obtain the cylinder head heat treatment simulation model;

[0010] Simulation method of cylinder head casting simulation model: Based on the heat treatment simulation model, a cylinder head casting simulation auxiliary model is added, and the model is partitioned to simulate the formation and details of the blank model in the casting process;

[0011] Simulation method of cylinder head calculation and analysis simulation model: Based on the cylinder head product design model, boundary conditions are set, and auxiliary models required for thermal-mechanical coupling stress calculation are added, such as water cavity CFD simulation, temperature field simulation, thermal-mechanical coupling stress calculation and fatigue assessment.

[0012] Furthermore, the simulation method of the cylinder head machining simulation model includes:

[0013] Model construction: First, we start with the CAD design model of the cylinder head, extract the geometric information required for machining, and obtain the blank model before machining through Boolean operations. This model is the difference between the design model and the casting blank model.

[0014] Casting simulation: Use casting simulation software to simulate based on casting process parameters;

[0015] Defect prediction: Through casting simulation, possible casting defects can be predicted to optimize the casting process design and ensure the quality of castings.

[0016] Furthermore, in the model construction, it includes:

[0017] Assume M design To design the model, M casting For the casting blank model, the blank model before machining M machining It is expressed as:

[0018] M machining =M design -M casting .

[0019] Furthermore, in the casting simulation, it includes:

[0020] The casting process is described by the following formula:

[0021]

[0022] Where, L is the latent heat and fs is the solid fraction.

[0023] Furthermore, the simulation method of the cylinder head heat treatment simulation model includes:

[0024] Setting heat treatment boundary conditions: First, according to the heat treatment process requirements, define the boundary conditions during the heat treatment process, which include heating temperature, cooling rate, and ambient temperature;

[0025] Heat treatment simulation: Based on the blank model after machining, heat treatment simulation software is used for simulation. By solving the heat conduction equation, the temperature field distribution in the entire heat treatment process is simulated;

[0026] Stress analysis: Calculate thermal stress and residual stress through the distribution of temperature field.

[0027] Furthermore, in the heat treatment simulation, the temperature field distribution in the entire heat treatment process is simulated by solving the heat conduction equation:

[0028]

[0029] Among them, ρ is the material density, c is the specific heat capacity, T is the temperature, k is the thermal conductivity, and Q is the heat source top.

[0030] Furthermore, in the stress analysis, the calculation of thermal stress depends on the thermal expansion coefficient α of the material and the temperature field change:

[0031] σ thermal =Eα(T-T0);

[0032] Where E is the elastic modulus and T0 is the reference temperature.

[0033] Furthermore, the simulation method of the cylinder head casting simulation model includes:

[0034] Design casting process design: Based on the heat treatment simulation model, design the casting process, which includes the design of the pouring system, the chilling system, the shrinkage feeding system and the casting mold;

[0035] Casting simulation: Use casting simulation software to simulate based on casting process parameters;

[0036] Defect Prediction: Through casting simulation, possible casting defects such as pores, slag inclusions and shrinkage holes can be predicted.

[0037] Furthermore, in the casting simulation, during the casting process, the temperature field and the solidification process are described by the following equations:

[0038]

[0039] Where L is the latent heat and fs is the solid fraction.

[0040] Furthermore, the simulation method of the cylinder head calculation analysis simulation model includes:

[0041] CFD simulation: Based on the design model of the cylinder head, CFD simulation of the water cavity is performed;

[0042] Temperature field simulation: Use FEM to simulate the temperature field to analyze the uniformity of temperature distribution of the cylinder head during operation;

[0043] Thermal-mechanical coupling stress calculation: Based on the temperature field simulation results, thermal-mechanical coupling stress calculation is further performed to evaluate the comprehensive impact of mechanical stress and thermal stress on the cylinder head during operation;

[0044] Fatigue assessment: Based on the calculation results of thermal-mechanical coupling stress, fatigue assessment is performed on the cylinder head to predict its life.

[0045] Furthermore, in the CFD simulation, the flow field and temperature field of the cooling water flow in the cylinder head during operation are analyzed, and the Navier-Stokes equation is solved to obtain the fluid velocity field v and pressure field p:

[0046]

[0047] Where μ is the dynamic viscosity and f is the volume force.

[0048] Furthermore, in the calculation of the thermomechanical coupling stress, the following thermomechanical coupling equation is used for calculation:

[0049] σ total =σ thermal +σ mechanical ;

[0050] Among them, σ mechanical is the mechanical stress caused by external load, σ thermal For heat stress.

[0051] Furthermore, in the fatigue assessment, fatigue analysis is performed using SN curves or fracture mechanics methods:

[0052]

[0053] Among them, N f is fatigue life, σ a is the stress amplitude, σ fatigue is the fatigue limit and b is the material constant.

[0054] Compared with the prior art, the integrated simulation method based on the whole process of cylinder head manufacturing described in the present invention has the following advantages:

[0055] (1) The integrated model of the present invention includes a casting process, a heat treatment process, a machining process and a computational analysis and evaluation, that is, the integrated model can be decomposed into a cylinder head casting simulation model, a cylinder head heat treatment simulation model, a cylinder head machining simulation model, a cylinder head computational analysis model and a cylinder head product design model, and can be directly used for casting process simulation, heat treatment process simulation, machining process simulation, computational analysis and product engineering drawing generation;

[0056] (2) The integrated model of the present invention comprehensively considers various simulation requirements of the entire cylinder head manufacturing process, such as heat treatment thermal boundary condition application partitioning, cylinder head water cavity CFD simulation, cylinder head temperature field simulation, cylinder head thermal-mechanical coupling stress simulation, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0058] Figure 1 It is a simulation model based on the whole process of cylinder head manufacturing;

[0059] Figure 2 Design models for cylinder head products;

[0060] Figure 3 Simulation model for the cylinder head machining process;

[0061] Figure 4 Simulation model for the cylinder head heat treatment process;

[0062] Figure 5 Simulation model for cylinder head casting process;

[0063] Figure 6 Compute and analyze simulation models for cylinder heads. DETAILED DESCRIPTION

[0064] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0065] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0066] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0067] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0068] In order to improve the efficiency and accuracy of information transmission in the entire manufacturing process, and thus perform more accurate calculation and analysis on the cylinder head, the present invention constructs a simulation model based on the entire cylinder head manufacturing process. The model includes the following steps:

[0069] Step 1: Build a cylinder head machining simulation model:

[0070] In the cylinder head product design model (see Figure 2 ), the part removed by machining is completed (i.e., the difference set of the cylinder head blank model and the cylinder head product design model), and the cylinder head product design model and the cylinder head blank model and the difference set of the cylinder head product design model are defined as two areas, and the two areas are combined to construct the cylinder head blank. The change from the cylinder head blank to the cylinder head product design model is the machining simulation process;

[0071] Step 2: Build a cylinder head heat treatment simulation model:

[0072] For the cylinder head blank obtained in step 1, adding partitions to the cylinder head blank according to the requirements of the heat treatment boundary conditions to obtain a cylinder head heat treatment simulation model;

[0073] Step 3: Build a cylinder head casting simulation model:

[0074] To the cylinder head heat treatment simulation model obtained in step 2, that is, the blank model with the heat treatment boundary conditions and the required partitioning, add the cylinder head casting simulation auxiliary model (pouring system, chilling system, feeding system, casting mold, etc.), partition the blank model and the casting simulation auxiliary model separately, and obtain the cylinder head casting simulation model;

[0075] Step 4: Build a cylinder head calculation and analysis simulation model:

[0076] Based on the cylinder head product design model, the boundary setting partitions required for CFD simulation of the cylinder head water cavity and the partitions required for temperature field simulation are set, and the auxiliary models required for thermal-mechanical coupling stress calculation (engine body, cylinder liner, cylinder gasket and bolts, etc.) are added.

[0077] In step one, the cylinder head blank model includes a cylinder head product design model and a difference set between the cylinder head blank model and the cylinder head product design model.

[0078] In step 1, the cylinder head machining simulation model includes the cylinder head blank model and the partitions required for machining simulation. Figure 2 .

[0079] In step 2, the cylinder head heat treatment simulation model includes: the cylinder head blank model and the heat treatment thermal boundary condition application partition, see Figure 3 .

[0080] In step 3, the cylinder head casting process simulation model includes: cylinder head blank model and cylinder head casting simulation auxiliary model (runner, chill, riser and casting mold), see Figure 4 .

[0081] In step 4, the cylinder head calculation and analysis simulation model includes: cylinder head product design model, water cavity CFD simulation and temperature field simulation partition, thermal-mechanical coupling stress calculation and auxiliary models required for fatigue assessment (engine body, cylinder liner, cylinder gasket and bolts, etc.), see details. Figure 5 .

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An integrated simulation method based on the entire process of cylinder head manufacturing, characterized in that: include: Simulation method of cylinder head machining simulation model: Based on the cylinder head product design model, the parts removed by machining are completed, and the model is defined as different areas. A complete cylinder head blank model is constructed by combining different areas, thereby simulating the changes in the machining process; Simulation method of cylinder head heat treatment simulation model: Based on the machining simulation model, partition processing is performed according to the boundary conditions of heat treatment to obtain the cylinder head heat treatment simulation model; Simulation method of cylinder head casting simulation model: Based on the heat treatment simulation model, a cylinder head casting simulation auxiliary model is added, and the model is partitioned to simulate the formation and details of the blank model in the casting process; Simulation method of cylinder head calculation and analysis simulation model: Based on the cylinder head product design model, boundary conditions are set, and auxiliary models required for thermal-mechanical coupling stress calculation are added, such as water cavity CFD simulation, temperature field simulation, thermal-mechanical coupling stress calculation and fatigue assessment.

2. The integrated simulation method based on the whole process of cylinder head manufacturing according to claim 1 is characterized in that: The simulation method of the cylinder head machining simulation model comprises: Model construction: First, we start with the CAD design model of the cylinder head, extract the geometric information required for machining, and obtain the blank model before machining through Boolean operations. This model is the difference between the design model and the casting blank model. Casting simulation: Use casting simulation software to simulate based on casting process parameters; Defect prediction: Through casting simulation, possible casting defects can be predicted to optimize the casting process design and ensure the quality of castings.

3. An integrated simulation method based on the whole process of cylinder head manufacturing according to claim 2, characterized in that: The model construction includes: Assume M design To design the model, M casting For the casting blank model, the blank model before machining M machining It is expressed as: M machining =M design -M casting 。 4. The integrated simulation method based on the whole process of cylinder head manufacturing according to claim 1 is characterized in that: The casting simulation includes: The casting process is described by the following formula: Where, L is the latent heat and fs is the solid fraction.

5. The integrated simulation method based on the whole process of cylinder head manufacturing according to claim 1 is characterized in that: The simulation method of the cylinder head heat treatment simulation model comprises: Setting heat treatment boundary conditions: First, according to the heat treatment process requirements, define the boundary conditions during the heat treatment process, which include heating temperature, cooling rate, and ambient temperature; Heat treatment simulation: Based on the blank model after machining, heat treatment simulation software is used for simulation. By solving the heat conduction equation, the temperature field distribution in the entire heat treatment process is simulated; Stress analysis: Calculate thermal stress and residual stress through the distribution of temperature field.

6. The integrated simulation method based on the whole process of cylinder head manufacturing according to claim 5 is characterized in that: In the heat treatment simulation, the temperature field distribution in the entire heat treatment process is simulated by solving the heat conduction equation: Where ρ is the material density, c is the specific heat, T is the temperature, k is the thermal conductivity, and Q is the heat source term.

7. The integrated simulation method based on the whole process of cylinder head manufacturing according to claim 5 is characterized in that: In the stress analysis, the calculation of thermal stress depends on the thermal expansion coefficient α of the material and the temperature field change: s thermal =Eα(T-T0); Where E is the elastic modulus and T0 is the reference temperature.

8. The integrated simulation method based on the whole process of cylinder head manufacturing according to claim 1 is characterized in that: The simulation method of the cylinder head casting simulation model comprises: Design casting process design: Based on the heat treatment simulation model, design the casting process, which includes the design of the pouring system, the chilling system, the shrinkage feeding system and the casting mold; Casting simulation: Use casting simulation software to simulate based on casting process parameters; Defect Prediction: Through casting simulation, possible casting defects such as pores, slag inclusions and shrinkage holes can be predicted.

9. The integrated simulation method based on the whole process of cylinder head manufacturing according to claim 8 is characterized in that: In the casting simulation, the temperature field and solidification process during the casting process are described by the following equations: Where L is the latent heat and fs is the solid fraction.

10. The integrated simulation method based on the whole process of cylinder head manufacturing according to claim 1, characterized in that: The simulation method of the cylinder head calculation analysis simulation model includes: CFD simulation: Based on the design model of the cylinder head, CFD simulation of the water cavity is performed; Temperature field simulation: Use FEM to simulate the temperature field to analyze the uniformity of temperature distribution of the cylinder head during operation; Thermal-mechanical coupling stress calculation: Based on the temperature field simulation results, thermal-mechanical coupling stress calculation is further performed to evaluate the comprehensive impact of mechanical stress and thermal stress on the cylinder head during operation; Fatigue assessment: Based on the calculation results of thermal-mechanical coupling stress, fatigue assessment is performed on the cylinder head to predict its lifespan; In the CFD simulation, the flow field and temperature field of the cooling water flow in the cylinder head during operation are analyzed, and the Navier-Stokes equation is solved to obtain the fluid velocity field v and pressure field p: Where μ is the dynamic viscosity, f is the volume force; In the thermomechanical coupling stress calculation, the following thermomechanical coupling equation is used for calculation: s total =s thermal +s mechanical ; Among them, σ mechanical is the mechanical stress caused by external load, σ thermal for thermal stress; In the fatigue assessment, fatigue analysis is performed using SN curves or fracture mechanics methods: Among them, N f is fatigue life, σa is stress amplitude, σ fatigue is the fatigue limit and b is the material constant.

Images