A simulation prediction method and system for the heat release of an engine water jacket

Abstract

An embodiment of the present application discloses a method and a system for simulating and predicting the heat release amount of an engine water jacket. The method includes: obtaining an exhaust gas flow boundary, an in-cylinder temperature distribution boundary, and a convective heat transfer coefficient between the gas and the cylinder block and cylinder head based on the engine water temperature, the intake manifold temperature, and preset combustion parameters; obtaining the coolant flow rates at the inlet and outlet of each water jacket; and predicting the heat release amount of the engine water jacket based on the exhaust gas flow boundary, the in-cylinder temperature distribution boundary, the convective heat transfer coefficient between the gas and the cylinder block and cylinder head, and the coolant flow rates at the inlet and outlet of each water jacket.

Description

Technical Field

[0001] This application relates to the technical field of engines, and in particular to a method and system for simulating and predicting the heat release of an engine water jacket. Background Art

[0002] The method for simulating and predicting the heat release of an engine water jacket is mainly applicable to the process of engine development. When the physical prototype has not been trial-produced yet, it is necessary to evaluate and predict the heat release data of the engine under characteristic working conditions to provide the corresponding cooling heat balance system for vehicle installation and development. Currently, there is no relevant technology for predicting the heat release data of the engine water jacket. Summary of the Invention

[0003] To solve the above technical problems, the embodiments of this application provide a method and system for simulating and predicting the heat release of an engine water jacket.

[0004] The technical solution of the embodiments of this application is implemented as follows:

[0005] In a first aspect, the embodiments of this application provide a method for simulating and predicting the heat release of an engine water jacket. The method includes:

[0006] Based on the engine water temperature, intake manifold temperature, and preset combustion parameters, obtain the exhaust gas flow boundary, in-cylinder temperature distribution boundary, and convective heat transfer coefficient between the gas and the cylinder block and cylinder head;

[0007] Obtain the coolant flow rates at each inlet and outlet of the water jacket;

[0008] Based on the exhaust gas flow boundary, in-cylinder temperature distribution boundary, convective heat transfer coefficient between the gas and the cylinder block and cylinder head, and the coolant flow rates at each inlet and outlet of the water jacket, predict the heat release of the engine water jacket.

[0009] In a second aspect, the embodiments of this application provide a system for simulating and predicting the heat release of an engine water jacket. The system includes:

[0010] A simulation module: used to obtain the exhaust gas flow boundary, in-cylinder temperature distribution boundary, and convective heat transfer coefficient between the gas and the cylinder block and cylinder head based on the engine water temperature, intake manifold temperature, and preset combustion parameters; obtain the coolant flow rates at each inlet and outlet of the water jacket; and predict the heat release of the engine water jacket based on the exhaust gas flow boundary, in-cylinder temperature distribution boundary, convective heat transfer coefficient between the gas and the cylinder block and cylinder head, and the coolant flow rates at each inlet and outlet of the water jacket.

[0011] The technical solution provided by the embodiments of this application can predict the engine heat release information in the early stage of development, enable the vehicle heat balance development work to start as early as possible, achieve the heat balance assessment test at one time, and avoid large deviations between the early rough estimate of the heat release and the test results of the engine prototype, resulting in repeated design changes of the vehicle. Brief Description of the Drawings

[0012] Figure 1 It is a flowchart of the method for simulating and predicting the heat release of the engine water jacket provided by the embodiments of the present application. Figure 1 ;

[0013] Figure 2 It is a flowchart of the method for simulating and predicting the heat release of the engine water jacket provided by the embodiments of the present application. Figure 2 ;

[0014] Figure 3 It is a schematic diagram of the system for simulating and predicting the heat release of the engine water jacket provided by the embodiments of the present application. Detailed implementation manners

[0015] Next, the technical solutions in the embodiments of the present application will be described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0016] It should be noted that in the embodiments of the present application, the term "and / or" only describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the embodiments of the present application, the character " / " generally represents an "or" relationship between the associated objects before and after.

[0017] In the description of the embodiments of the present application, the term "corresponding" can represent a direct or indirect corresponding relationship between two, can also represent an association relationship between two, or can be an indication and being indicated, configuration and being configured, etc.

[0018] To facilitate the understanding of the technical solutions in the embodiments of the present application, the related technologies in the embodiments of the present application are described as follows:

[0019] Mean effective pressure (International Materiel Evaluation Program, IMEP): The indicated work per unit cylinder working volume is called the mean indicated pressure.

[0020] Indicated specific fuel consumption (ISFC): The specific fuel consumption, that is, the fuel consumption rate, refers to the mass of fuel consumed by the engine per 1 kw of indicated power in 1 h (in g), represented by ge, and the unit is g / (kw·h).

[0021] In order to understand the features and technical content of this application in more detail, the implementation of this application will be elaborated in detail below with reference to the accompanying drawings. The attached drawings are only for reference and explanation purposes and are not used to limit this application.

[0022] Figure 1 Schematic diagram of the implementation process of a method for simulating and predicting the heat release of an engine water jacket provided by an embodiment of this application Figure 1 , such as Figure 1 shown, an embodiment of this application provides a method for simulating and predicting the heat release of an engine water jacket, and the method includes:

[0023] Step 101: Based on the engine water temperature, intake manifold temperature, and preset combustion parameters, obtain the exhaust gas flow boundary, in-cylinder temperature distribution boundary, and convective heat transfer coefficient between the gas and the cylinder block and cylinder head.

[0024] Here, the exhaust gas flow boundary, in-cylinder temperature distribution boundary, and convective heat transfer coefficient between the gas and the cylinder block and cylinder head can be obtained through the iterative process of thermodynamic performance simulation and the iterative process of combustion system simulation. When both the thermodynamic performance simulation and the combustion system simulation are iteratively stable, the thermodynamic performance simulation outputs the exhaust gas flow boundary, and the combustion system outputs the convective heat transfer coefficient between the gas and the cylinder block and cylinder head. The IMEP and ISFC of the thermodynamic performance simulation and the combustion system simulation can be used to determine whether the iterative processes of the thermodynamic performance simulation and the combustion system simulation converge. When both the IMEP and ISFC converge, the iterative processes of the thermodynamic performance simulation and the combustion system simulation both converge.

[0025] Specifically, each iterative process of the thermodynamic performance simulation includes: performing thermodynamic performance simulation based on the engine water temperature, intake manifold temperature, and combustion parameters, and outputting the transient intake gas flow and pressure boundary. In the first iterative process, thermodynamic performance simulation can be performed based on the engine water temperature, intake manifold temperature, and preset combustion parameters to output the transient intake gas flow and pressure boundary. In non-first iterative processes, based on the engine water temperature, intake manifold temperature, and combustion parameters output by the combustion system simulation, the transient intake gas flow and pressure boundary are output; each iterative process of the combustion system simulation includes performing combustion system simulation based on the transient intake gas flow and pressure boundary output by the thermodynamic performance simulation, and outputting combustion parameters. The combustion parameters include: cylinder pressure curve, CA10, CA50, CA90, where CA10, CA50, and CA90 respectively represent the crankshaft angles corresponding to 10%, 50%, and 90% fuel combustion during the combustion process.

[0026] Based on this, for the method for simulating and predicting the heat release of an engine water jacket provided by another embodiment of this application, the obtaining of the exhaust gas flow, temperature boundary, in-cylinder temperature distribution boundary, and convective heat transfer coefficient between the gas and the cylinder block and cylinder head based on the engine water temperature, intake manifold temperature, and preset combustion parameters includes:

[0027] Perform the iterative processes of thermodynamic performance simulation and combustion system simulation until the IMEP and ISFC of both the thermodynamic performance simulation and the combustion system simulation converge; based on the outputs of the converged thermodynamic performance simulation and the combustion system simulation, obtain the exhaust gas flow boundary, the in-cylinder temperature distribution boundary, and the convective heat transfer coefficient between the gas and the cylinder block and cylinder head.

[0028] Among them, each iterative process of the thermodynamic performance simulation includes: performing thermodynamic performance simulation based on the engine water temperature, intake manifold temperature, and combustion parameters, and outputting the transient intake air flow and pressure boundary; in the first iterative process, the combustion parameters are preset combustion parameters; in non-first iterative processes, the combustion parameters are the combustion parameters output by the combustion system simulation.

[0029] Each iterative process of the combustion system simulation includes: performing combustion system simulation based on the transient intake air flow and pressure boundary output by the thermodynamic performance simulation, and outputting combustion parameters.

[0030] Furthermore, for the thermodynamic performance simulation, it can be completed based on specific simulation software, such as GT-Power and AVL-Boost, which are used to analyze the working state of the engine. According to the geometric parameters of the engine and the performance data of components such as the supercharger, an engine thermodynamic model is constructed, combustion parameters are set, and engine thermodynamic simulation is carried out. After the working conditions are iteratively stabilized (the cyclic fluctuations of torque, intake pressure, and exhaust temperature are less than 0.1%), the transient pressure, flow, and temperature data of the last cycle are taken. The transient intake air flow and pressure boundary refer to the data of the fresh gas mass flow entering the cylinder varying with the crankshaft angle under specific engine working conditions (engine speed, torque) (the crankshaft rotation angle of one cycle is 720°). For the engine thermodynamic performance simulation, a knock prediction function is required. Therefore, when performing simulation analysis, the influence of the intake manifold temperature and the engine water temperature on engine knock needs to be considered. Here, the geometric parameters are the cylinder diameter, stroke, connecting rod length, piston offset, and the shapes of the intake and exhaust manifolds, etc.

[0031] For the combustion system simulation, it can be completed based on specific simulation software, such as AVL-Fire and Converge. According to the digital models of the engine cylinder head, cylinder block, piston, and valve number, a combustion system simulation model is constructed, the transient intake air flow and intake pressure boundary data are input, the ignition advance angle is set, and numerical simulation and prediction of the combustion process are carried out. According to the analysis results, combustion process data such as the cylinder pressure curve, CA10, CA50, and CA90 are derived. At the same time, the gas temperature and convective heat transfer coefficient results of the contact surface between the cylinder block, cylinder head, and combustion gas are derived.

[0032] It is possible to determine whether the IMEP and ISFC of the above-mentioned thermodynamic performance simulation and combustion system simulation converge in the following way. Compare the growth rate or decline rate of the IMEP value of the combustion system simulation in the current iteration process compared to the IMEP value of the thermodynamic performance simulation with a preset second threshold, and compare the growth rate or decline rate of the ISFC value of the combustion system simulation in the current iteration process compared to the ISFC value of the thermodynamic performance simulation with the preset second threshold. If both are less than or equal to the preset second threshold, the IMEP and ISFC of the thermodynamic performance simulation and the combustion system simulation both converge.

[0033] Based on this, for the engine water jacket heat release simulation prediction method provided by an embodiment of the present application, where the IMEP and ISFC of the thermodynamic performance simulation and the combustion system simulation both converge, it includes:

[0034] Compare the growth rate or decline rate of the IMEP of the combustion system simulation in the current iteration process compared to the IMEP of the thermodynamic performance simulation and the growth rate or decline rate of the ISFC of the combustion system simulation in the current iteration process compared to the ISFC of the thermodynamic performance simulation with the preset second threshold respectively. If both are less than or equal to the preset second threshold, the IMEP and ISFC of the thermodynamic performance simulation and the combustion system simulation both converge.

[0035] In an embodiment of the present application, the preset second threshold is 3%.

[0036] Step 102: Obtain the coolant flow rates at the inlet and outlet of the water jacket.

[0037] Here, the coolant flow rates at the inlet and outlet of the water jacket can be obtained through cooling system simulation.

[0038] Based on this, for the engine water jacket heat release simulation prediction method provided by an embodiment of the present application, the obtaining of the coolant flow rates at the inlet and outlet of the water jacket includes:

[0039] Conduct a cooling system simulation to obtain the coolant flow rates at the inlet and outlet of the water jacket.

[0040] Specifically, the cooling system simulation is a simulation work in engine development. It can be based on specific simulation software, such as GT-Power, Flowmaster, or can also be balanced and calculated through tools such as excel. The cooling system pipeline constructs a cooling system simulation model according to the solid digital model. The flow resistance of components and the performance of the water pump adopt the flow rate - pressure drop curve data measured in experiments, and the cooling flow rates through each component at different engine speeds are obtained through simulation analysis.

[0041] Step 103: Predict the heat release of the engine water jacket based on the exhaust gas flow boundary, in-cylinder temperature distribution boundary, convective heat transfer coefficient between the gas and the cylinder block and cylinder head, and the coolant flow rates at the inlet and outlet of the water jacket.

[0042] Here, the heat release of the engine water jacket can be obtained through the iterative process of the water jacket CFD simulation and the iterative process of the cylinder block and cylinder head temperature field simulation. Specifically, when the temperature distribution boundary of the cylinder block and cylinder head in the water jacket CFD simulation converges, based on the output of the converged water jacket CFD simulation, the statistical result of the solid surface heat transfer power of the water jacket CFD simulation is obtained, that is, the heat release result of the engine water jacket.

[0043] Furthermore, each iterative process of the water jacket CFD simulation includes: performing a water jacket CFD simulation based on the coolant flow rates at the inlet and outlet of the water jacket and the temperature distribution boundary of the cylinder block and cylinder head obtained in step 102, and outputting the coolant temperature distribution and the convective heat transfer coefficient between the coolant and the cylinder block and cylinder head; in the first iterative process, the temperature distribution boundary of the cylinder block and cylinder head is the preset temperature distribution boundary of the cylinder block and cylinder head; in the non-first iterative process, the temperature distribution boundary of the cylinder block and cylinder head is the temperature distribution boundary of the cylinder block and cylinder head output by the cylinder block and cylinder head temperature field simulation. Each iterative process of the cylinder block and cylinder head temperature field simulation includes: performing a cylinder block and cylinder head temperature field simulation based on the exhaust gas flow rate boundary, the in-cylinder temperature distribution boundary, the convective heat transfer coefficient between the gas and the cylinder block and cylinder head, the coolant temperature distribution, and the convective heat transfer coefficient between the coolant and the cylinder block and cylinder head, and outputting the temperature distribution boundary of the cylinder block and cylinder head.

[0044] Based on this, for the engine water jacket heat release simulation prediction method provided by another embodiment of the present application, predicting the heat release of the engine water jacket based on the exhaust gas flow rate boundary, the in-cylinder temperature distribution boundary, the convective heat transfer coefficient between the gas and the cylinder block and cylinder head, and the coolant flow rates at the inlet and outlet of the water jacket includes:

[0045] Performing the iterative process of the water jacket CFD simulation and the iterative process of the cylinder block and cylinder head temperature field simulation until the temperature distribution boundary of the cylinder block and cylinder head in the input water jacket CFD simulation converges; based on the output of the converged water jacket CFD simulation, obtaining the statistical result of the solid surface heat transfer power of the water jacket CFD simulation, that is, the heat release result of the engine water jacket.

[0046] Wherein, each iterative process of the water jacket CFD simulation includes: performing a water jacket CFD simulation based on the coolant flow rates at the inlet and outlet of the water jacket and the temperature distribution boundary of the cylinder block and cylinder head, and outputting the coolant temperature distribution and the convective heat transfer coefficient between the coolant and the cylinder block and cylinder head; in the first iterative process, the temperature distribution boundary of the cylinder block and cylinder head is the preset temperature distribution boundary of the cylinder block and cylinder head; in the non-first iterative process, the temperature distribution boundary of the cylinder block and cylinder head is the temperature distribution boundary of the cylinder block and cylinder head output by the cylinder block and cylinder head temperature field simulation;

[0047] Each iteration process of the cylinder block and cylinder head temperature field simulation includes: performing the cylinder block and cylinder head temperature field simulation based on the exhaust gas flow boundary, the in-cylinder temperature distribution boundary, the convective heat transfer coefficient between the gas and the cylinder block and cylinder head, the coolant temperature distribution, and the convective heat transfer coefficient between the coolant and the cylinder block and cylinder head, and outputting the cylinder block and cylinder head temperature distribution boundary.

[0048] For the water jacket CFD simulation, it can be completed based on specific simulation software, such as STAR-CCM+. According to the digital models of the engine cylinder block and cylinder head, a cold water jacket model is constructed. The flow boundaries at the inlets and outlets of the water jacket are set according to the flow results of the cooling system simulation, and the coolant pressure and temperature boundaries at the outlet of the water jacket are set with reference to the cooling system analysis results. The flow field distribution of the coolant in the water jacket, the convective heat transfer coefficient at the contact surface with the cylinder block and cylinder head, and the coolant temperature distribution are obtained through simulation.

[0049] For the temperature field simulation, it can be completed based on specific simulation software, such as Abaqus. A temperature field simulation model is constructed according to the digital models of the engine cylinder block and cylinder head, and the mesh is divided. Based on the combustion system simulation results, the temperature, pressure, and convective heat transfer coefficient at the contact surface between the cylinder block, cylinder head and the gas side are input. At the same time, according to the water jacket CFD simulation results, the temperature, pressure, and convective heat transfer coefficient at the contact surface between the cylinder block, cylinder head and the coolant are input, and the heat transfer process of the solid parts of the cylinder block and cylinder head is calculated to obtain the wall temperature and temperature distribution results of the cylinder block and cylinder head.

[0050] The convergence of the cylinder block and cylinder head temperature distribution boundary input into the water jacket CFD simulation can be judged in the following way. Compare the growth rate or decline rate of the cylinder block and cylinder head temperature distribution boundary input into the water jacket CFD in the current iteration process compared with the cylinder block and cylinder head temperature distribution boundary input into the water jacket CFD in the previous iteration with a preset first threshold. If it is less than or equal to the preset first threshold, then the cylinder block and cylinder head temperature distribution boundary converges.

[0051] Based on this, for the engine water jacket heat release simulation prediction method provided by an embodiment of the present application, the cylinder block and cylinder head temperature distribution boundary input into the water jacket CFD simulation converges, including:

[0052] Compare the growth rate or decline rate of the cylinder block and cylinder head temperature distribution boundary input into the water jacket CFD in the current iteration process compared with the cylinder block and cylinder head temperature distribution boundary input into the water jacket CFD in the previous iteration with a preset first threshold. If it is less than or equal to the preset first threshold, then the cylinder block and cylinder head temperature distribution boundary converges.

[0053] It should be noted that the in-cylinder temperature distribution boundary refers to the temperature distribution boundary of the in-cylinder gas on the cylinder block and cylinder head, and the cylinder block and cylinder head temperature distribution boundary refers to the temperature distribution boundary of the coolant on the cylinder block and cylinder head.

[0054] The engine water jacket heat release simulation prediction method provided by the above embodiments of the present application improves the analysis accuracy through complete boundary mapping and multi-round iterative analysis, ensuring the accuracy of the water jacket heat release prediction. Moreover, this solution introduces the intake manifold temperature and the engine water temperature boundary, fully considering the influence of environmental factors on the engine heat release, and is applicable to the heat release prediction under a relatively wide range of environmental conditions, realizing the prediction and analysis function of the engine water jacket heat release.

[0055] In another embodiment of the present application, the preset first threshold is 3%.

[0056] Figure 2 It is a schematic implementation process of the engine water jacket heat release simulation prediction method provided by another embodiment of the present application Figure 2 , such as Figure 2 shown. The engine water jacket heat release simulation prediction method provided by this embodiment includes the following steps:

[0057] Step 201: According to the geometric structure and performance objectives of the engine, conduct thermodynamic performance simulation. This simulation task needs to have the function of knock prediction, and consider the influence of the intake manifold temperature and the engine water temperature on the engine knock during analysis; the thermodynamic performance simulation outputs the transient flow rate and pressure boundaries of all intake and exhaust ports within each engine cycle.

[0058] Step 202: The combustion system simulation uses the transient intake flow rate and pressure boundaries as inputs for simulation and outputs combustion parameters.

[0059] Step 203: The thermodynamic performance simulation updates the combustion parameters according to the combustion simulation results for simulation, and updates the transient flow rate and pressure boundaries of the intake and exhaust ports again.

[0060] Step 204: The combustion system simulation updates the transient intake flow rate and pressure boundaries and conducts simulation again.

[0061] Step 205: Compare the IMEP and ISFC of the thermodynamic performance simulation and the combustion system simulation. A deviation > 3% is regarded as the iteration not converging, and return to Step 203; a deviation ≤ 3% is regarded as the iteration converging. The combustion system simulation outputs the in-cylinder temperature distribution boundary and the convective heat transfer coefficient between the gas and the cylinder block and cylinder head, and the thermodynamic simulation outputs the exhaust flow rate boundary.

[0062] Step 206: Conduct engine cooling system simulation to analyze and obtain the coolant flow rates at the inlet and outlet of the water jacket.

[0063] Step 207: Conduct water jacket CFD simulation, input the flow rate boundary of the cooling system, estimate and input the temperature boundary of the cylinder block and cylinder head, and analyze to obtain the coolant temperature distribution and the convective heat transfer coefficient between the coolant and the cylinder block and cylinder head.

[0064] Step 208: Based on the in-cylinder temperature distribution boundary output by the combustion system simulation, the convective heat transfer coefficient between the gas and the cylinder block and cylinder head, the exhaust gas flow boundary output by the thermodynamic simulation, and the coolant temperature distribution and the convective heat transfer coefficient between the coolant and the cylinder block and cylinder head output by the water jacket CFD analysis, perform a temperature field simulation of the cylinder block and cylinder head to obtain the temperature distribution boundary of the cylinder block and cylinder head.

[0065] Step 209: The water jacket CFD uses the temperature distribution boundary of the cylinder block and cylinder head mapped from the temperature field analysis as input and performs simulation again.

[0066] Step 210: Compare the temperature distributions of the cylinder block and cylinder head used in the two inputs of the water jacket CFD. If the deviation > 3%, it is considered not converged, and return to Step 208; if the deviation ≤ 3%, it is considered that the iteration converges, and output the statistical result of the solid surface heat transfer power of the water jacket CFD, which is the heat release result of the engine water jacket.

[0067] To implement the real-time advertisement program replacement method described in the application embodiment of the present application, the embodiment of the present application also provides an engine water jacket heat release simulation prediction system 300; Figure 3 For the structural schematic diagram of the engine water jacket heat release simulation prediction system 300 provided by the embodiment of the present application, as Figure 3 shown, the engine water jacket heat release simulation prediction system 300 provided by the application embodiment of the present application includes:

[0068] Simulation module 301: It is used to obtain the exhaust gas flow boundary, the in-cylinder temperature distribution boundary, and the convective heat transfer coefficient between the gas and the cylinder block and cylinder head based on the engine water temperature, the intake manifold temperature, and the preset combustion parameters; obtain the coolant flow rates at each inlet and outlet of the water jacket; and predict the heat release of the engine water jacket based on the exhaust gas flow boundary, the in-cylinder temperature distribution boundary, the convective heat transfer coefficient between the gas and the cylinder block and cylinder head, and the coolant flow rates at each inlet and outlet of the water jacket.

[0069] In other embodiments of the present application, the simulation module 301 is specifically used to perform the iterative process of the thermodynamic performance simulation and the iterative process of the combustion system simulation until both the IMEP and ISFC of the thermodynamic performance simulation and the combustion system simulation converge; based on the output of the converged thermodynamic performance simulation and the output of the combustion system simulation, obtain the exhaust gas flow boundary, the in-cylinder temperature distribution boundary, and the convective heat transfer coefficient between the gas and the cylinder block and cylinder head; wherein, each iterative process of the thermodynamic performance simulation includes: performing a thermodynamic performance simulation based on the engine water temperature, the intake manifold temperature, and the combustion parameters, and outputting the transient intake gas flow and pressure boundary; in the first iterative process, the combustion parameters are the preset combustion parameters; in the non-first iterative process, the combustion parameters are the combustion parameters output by the combustion system simulation; each iterative process of the combustion system simulation includes: performing a combustion system simulation based on the transient intake gas flow and pressure boundary output by the thermodynamic performance simulation, and outputting the combustion parameters.

[0070] In other embodiments of the present application, the simulation module 301 is specifically further configured to perform cooling system simulation to obtain the coolant flow rates at the inlets and outlets of the water jacket.

[0071] In other embodiments of the present application, the simulation module 301 is specifically further configured to perform the iterative process of the water jacket CFD simulation and the iterative process of the cylinder block and cylinder head temperature field simulation until the temperature distribution boundary of the cylinder block and cylinder head input to the water jacket CFD simulation converges; based on the output of the water jacket CFD simulation after convergence, obtain the statistical result of the solid surface heat transfer power of the water jacket CFD simulation, which is the heat release result of the engine water jacket; wherein, each iterative process of the water jacket CFD simulation includes: performing water jacket CFD simulation based on the coolant flow rates at the inlets and outlets of the water jacket and the temperature distribution boundary of the cylinder block and cylinder head, and outputting the coolant temperature distribution and the convective heat transfer coefficient between the coolant and the cylinder block and cylinder head; in the first iterative process, the temperature distribution boundary of the cylinder block and cylinder head is the preset temperature distribution boundary of the cylinder block and cylinder head; in non-first iterative processes, the temperature distribution boundary of the cylinder block and cylinder head is the temperature distribution boundary of the cylinder block and cylinder head output by the cylinder block and cylinder head temperature field simulation; each iterative process of the cylinder block and cylinder head temperature field simulation includes: performing cylinder block and cylinder head temperature field simulation based on the exhaust gas flow rate boundary, the in-cylinder temperature distribution boundary, the convective heat transfer coefficient between the gas and the cylinder block and cylinder head, the coolant temperature distribution, and the convective heat transfer coefficient between the coolant and the cylinder block and cylinder head, and outputting the temperature distribution boundary of the cylinder block and cylinder head.

[0072] In other embodiments of the present application, the convergence of the temperature distribution boundary of the cylinder block and cylinder head input to the water jacket CFD simulation includes: comparing the growth rate or decline rate of the temperature distribution of the simulated cylinder block and cylinder head input to the water jacket CFD in the current iterative process with that in the previous input to the water jacket CFD simulation with a preset first threshold. If it is less than or equal to the preset first threshold, the temperature distribution boundary of the cylinder block and cylinder head converges.

[0073] In other embodiments of the present application, the convergence of both the IMEP and ISFC of the thermodynamic performance simulation and the combustion system simulation includes: comparing the growth rate or decline rate of the IMEP of the combustion system simulation in the current iterative process with that of the thermodynamic performance simulation and the growth rate or decline rate of the ISFC of the combustion system simulation in the current iterative process with that of the thermodynamic performance simulation with a preset second threshold respectively. If both are less than or equal to the preset second threshold, both the IMEP and ISFC of the thermodynamic performance simulation and the combustion system simulation converge.

[0074] Those skilled in the art should understand that Figure 3 The implementation functions of the various units in the shown engine water jacket heat release simulation prediction system can be understood with reference to the relevant descriptions of the foregoing methods. Figure 3The functions of the various units in the engine water jacket heat release simulation prediction system shown can be implemented by a program running on a processor or by specific logic circuits.

[0075] Those of ordinary skill in the art will realize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. A professional technician can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0076] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0077] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces, and the indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.

[0078] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0079] In addition, the various functional units in the various embodiments of this application can be integrated in one processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0080] When the above-mentioned function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of this application. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs that can store program codes.

[0081] As described above, the above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of changes or substitutions, which should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A simulation prediction method for the heat release of an engine water jacket, characterized in that Including: Based on the engine coolant temperature, intake manifold temperature, and preset combustion parameters, obtain the exhaust gas flow boundary, in-cylinder temperature distribution boundary, and convective heat transfer coefficient between the gas and the cylinder block and cylinder head; Obtain the coolant flow rates at the inlet and outlet of the water jacket; Perform the iterative process of water jacket CFD simulation and the iterative process of cylinder block and cylinder head temperature field simulation until the cylinder block and cylinder head temperature distribution boundary input to the water jacket CFD simulation converges; based on the output of the converged water jacket CFD simulation, obtain the statistical result of the solid surface heat transfer power of the water jacket CFD simulation, which is the heat release result of the engine water jacket; Wherein, each iterative process of the water jacket CFD simulation includes: performing water jacket CFD simulation based on the coolant flow rates at the inlet and outlet of the water jacket and the cylinder block and cylinder head temperature distribution boundary, and outputting the coolant temperature distribution and the convective heat transfer coefficient between the coolant and the cylinder block and cylinder head; in the first iterative process, the cylinder block and cylinder head temperature distribution boundary is the preset cylinder block and cylinder head temperature distribution boundary; in non-first iterative processes, the cylinder block and cylinder head temperature distribution boundary is the cylinder block and cylinder head temperature distribution boundary output by the cylinder block and cylinder head temperature field simulation; Each iterative process of the cylinder block and cylinder head temperature field simulation includes: performing cylinder block and cylinder head temperature field simulation based on the exhaust gas flow boundary, in-cylinder temperature distribution boundary, convective heat transfer coefficient between the gas and the cylinder block and cylinder head, coolant temperature distribution, and convective heat transfer coefficient between the coolant and the cylinder block and cylinder head, and outputting the cylinder block and cylinder head temperature distribution boundary.

2. The method for simulating and predicting the heat release amount of the engine water jacket according to claim 1, wherein Based on the engine coolant temperature, intake manifold temperature, and preset combustion parameters, obtaining the exhaust gas flow boundary, in-cylinder temperature distribution boundary, and convective heat transfer coefficient between the gas and the cylinder block and cylinder head includes: Performing the iterative process of thermodynamic performance simulation and the iterative process of combustion system simulation until both the IMEP and ISFC of the thermodynamic performance simulation and the combustion system simulation converge; based on the output of the converged thermodynamic performance simulation and the output of the combustion system simulation, obtain the exhaust gas flow boundary, in-cylinder temperature distribution boundary, and convective heat transfer coefficient between the gas and the cylinder block and cylinder head; Wherein, each iterative process of the thermodynamic performance simulation includes: performing thermodynamic performance simulation based on the engine coolant temperature, intake manifold temperature, and combustion parameters, and outputting the transient intake gas flow and pressure boundary; in the first iterative process, the combustion parameters are the preset combustion parameters; in non-first iterative processes, the combustion parameters are the combustion parameters output by the combustion system simulation; Each iterative process of the combustion system simulation includes: performing combustion system simulation based on the transient intake gas flow and pressure boundary output by the thermodynamic performance simulation, and outputting the combustion parameters.

3. The method for simulating and predicting the heat release amount of the engine water jacket according to claim 2, wherein, The obtaining of the coolant flow rates at the inlet and outlet of the water jacket includes: Performing cooling system simulation to obtain the coolant flow rates at the inlet and outlet of the water jacket.

4. The method for simulating and predicting the heat release amount of the engine water jacket according to claim 3, wherein The convergence of the cylinder block and cylinder head temperature distribution boundary input to the water jacket CFD simulation includes: Comparing the growth rate or decline rate of the cylinder block and cylinder head temperature distribution of the simulation input to the water jacket CFD in the current iterative process with that in the previous iterative process with a preset first threshold, and if it is less than or equal to the preset first threshold, then the cylinder block and cylinder head temperature distribution boundary converges.

5. The method for simulating and predicting the heat release amount of the engine water jacket according to any one of claims 2-4, characterized in that, Both the IMEP and ISFC of the thermodynamic performance simulation and the combustion system simulation converge, including: Comparing the growth rate or decline rate of the IMEP of the combustion system simulation in the current iteration process with the IMEP of the thermodynamic performance simulation and the growth rate or decline rate of the ISFC of the combustion system simulation in the current iteration process with the ISFC of the thermodynamic performance simulation with a preset second threshold respectively. If both are less than or equal to the preset second threshold, both the IMEP and ISFC of the thermodynamic performance simulation and the combustion system simulation converge.

6. An engine water jacket heat release simulation prediction system, characterized in that The system includes: A simulation module: used to obtain the exhaust gas flow boundary, the in-cylinder temperature distribution boundary, and the convective heat transfer coefficient between the gas and the cylinder block and cylinder head based on the engine coolant temperature, the intake manifold temperature, and preset combustion parameters; obtain the coolant flow rates at the inlet and outlet of the water jacket; perform the iterative process of the water jacket CFD simulation and the iterative process of the cylinder block and cylinder head temperature field simulation until the cylinder block and cylinder head temperature distribution boundary input to the water jacket CFD simulation converges; based on the output of the converged water jacket CFD simulation, obtain the statistical result of the solid surface heat transfer power of the water jacket CFD simulation, which is the result of the heat release of the engine water jacket. Wherein, each iterative process of the water jacket CFD simulation includes: performing the water jacket CFD simulation based on the coolant flow rates at the inlet and outlet of the water jacket and the cylinder block and cylinder head temperature distribution boundary, and outputting the coolant temperature distribution and the convective heat transfer coefficient between the coolant and the cylinder block and cylinder head; in the first iterative process, the cylinder block and cylinder head temperature distribution boundary is the preset cylinder block and cylinder head temperature distribution boundary; in the non-first iterative process, the cylinder block and cylinder head temperature distribution boundary is the cylinder block and cylinder head temperature distribution boundary output by the cylinder block and cylinder head temperature field simulation. Each iterative process of the cylinder block and cylinder head temperature field simulation includes: performing the cylinder block and cylinder head temperature field simulation based on the exhaust gas flow boundary, the in-cylinder temperature distribution boundary, the convective heat transfer coefficient between the gas and the cylinder block and cylinder head, the coolant temperature distribution, and the convective heat transfer coefficient between the coolant and the cylinder block and cylinder head, and outputting the cylinder block and cylinder head temperature distribution boundary.

7. The engine water jacket heat release simulation prediction system according to claim 6, wherein The simulation module is specifically used to perform the iterative process of the thermodynamic performance simulation and the iterative process of the combustion system simulation until both the IMEP and ISFC of the thermodynamic performance simulation and the combustion system simulation converge; based on the output of the converged thermodynamic performance simulation and the output of the combustion system simulation, obtain the exhaust gas flow boundary, the in-cylinder temperature distribution boundary, and the convective heat transfer coefficient between the gas and the cylinder block and cylinder head. Wherein, each iterative process of the thermodynamic performance simulation includes: performing the thermodynamic performance simulation based on the engine coolant temperature, the intake manifold temperature, and the combustion parameters, and outputting the transient intake air flow and pressure boundary; in the first iterative process, the combustion parameters are the preset combustion parameters; in the non-first iterative process, the combustion parameters are the combustion parameters output by the combustion system simulation. Each iterative process of the combustion system simulation includes: performing the combustion system simulation based on the transient intake air flow and pressure boundary output by the thermodynamic performance simulation, and outputting the combustion parameters.

8. The engine water jacket heat release simulation prediction system according to claim 7, wherein the simulation module is further specifically configured to perform a cooling system simulation to obtain the coolant flow rates at the inlets and outlets of the water jacket.

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