Engine cooling system analysis method, readable storage medium and analysis device

Abstract

The embodiments of the present invention provide an engine cooling system analysis method, a readable storage medium and an analysis device, the analysis method comprising: splitting the engine water jacket into a corresponding number of branches according to the number of water jacket inlets and water jacket outlets; fitting a resistance function relationship for each branch; using the fitted function relationship expression as the boundary condition of each corresponding outlet of the engine water jacket; monitoring whether the water jacket inlet is flow balanced, if so, it meets the requirements, if not, changing the boundary conditions of the outlet with the iteration step. In the technical solution of the present invention, a method of decomposing, transforming and entering a one-dimensional model into a three-dimensional model is adopted, and the balanced flow is accurately calculated in one time in the three-dimensional software. One calculation directly completes the previous calculation tasks of at least three times; for multiple outlets of the engine water jacket, there is no need to guess the flow ratio between the outlets, and the accurate result can be directly calculated, which is conducive to optimizing the algorithm, reducing the number of calculations, and improving the accuracy of the calculation.

Description

Technical Field

[0001] Embodiments of the present invention relate to the technical field of engine cooling systems, and in particular, to an engine cooling system analysis method, a readable storage medium, and an analysis device. Background Art

[0002] At present, when conducting three-dimensional heat transfer analysis of engine water jacket, the focus is on how to improve the calculation accuracy (using fluid-structure interaction) and improve the degree of automation (using scripts to standardize the analysis process). However, no attention is paid to the accuracy of the input boundary.

[0003] The general method to obtain the water jacket flow is as follows:

[0004] 1. When the water jacket has only a single inlet and outlet, a set of flow boundaries from small to large are directly given on the 3D CFD model of the water jacket, and the corresponding resistance is calculated respectively. Based on this, the water resistance parameters of the water jacket are generated.

[0005] Then, combined with the data of other parts of the cooling system, the water jacket flow rate is calculated through the one-dimensional cooling system model. This flow rate can be used as a boundary for the three-dimensional heat transfer analysis of the water jacket.

[0006] 2. However, when the water jacket has multiple outlets, it is still necessary to give a set of flow boundaries from small to large on the 3D CFD model of the water jacket, and then give the outlet flow distribution ratio based on the guesswork, and calculate the resistance of each outlet corresponding to each flow. Based on this, the water resistance parameters of each outlet of the water jacket are generated.

[0007] Then, combined with the data of other parts of the cooling system, the water jacket flow is calculated through the one-dimensional cooling system model. However, since the proportion of the outlet flow is guessed, it is necessary to confirm whether the outlet flow calculated by the one-dimensional cooling system is consistent with the guess. But usually it is not.

[0008] At this point, it is necessary to re-assume the flow ratio of the water jacket outlet, and then repeat the previous two steps until they match. This will consume a lot of time and energy. Therefore, there are also cases where accuracy is abandoned and the results calculated by the first round of assumptions are directly accepted. This will introduce deviations and inaccuracies to the analysis of the water jacket and the one-dimensional cooling system. When analyzing the heat transfer performance of the engine water jacket, it is actually necessary to exchange data with the one-dimensional cooling system analysis to obtain an accurate analysis boundary. Even the simplest case requires three calculations: calculation of the water jacket water resistance parameters, one-dimensional cooling system analysis, and water jacket heat transfer performance analysis. If the water jacket has more than two outlets, there are two situations: either spend time and energy on iteration, or accept inaccurate and biased results. Summary of the invention

[0009] In order to solve or improve at least one of the above technical problems, an object of an embodiment of the present invention is to provide an engine cooling system analysis method.

[0010] Another object of an embodiment of the present invention is to provide a readable storage medium.

[0011] Another object of an embodiment of the present invention is to provide an analysis device.

[0012] To achieve the above-mentioned purpose, an embodiment of the first aspect of the present invention provides an engine cooling system analysis method, comprising: dividing the engine cooling system into a corresponding number of branches according to the number of water jacket inlets and water jacket outlets of the engine water jacket; fitting a resistance function relationship for each branch; using the fitted function relationship expression as the boundary condition of each corresponding water jacket outlet, and establishing an association with each iteration step through an internal variable of iterative calculation; monitoring whether the flow at the water jacket inlet is balanced, if so, it meets the requirements, and if not, changing the boundary condition of the outlet with the iteration step.

[0013] According to the embodiment of the engine cooling system analysis method provided by the present invention, a method of decomposing, transforming and entering a one-dimensional model into a three-dimensional model is adopted to accurately calculate the balance flow in a one-time manner in the three-dimensional software. One calculation directly completes the task of at least three calculations in the past; for multiple outlets of the engine water jacket, there is no need to guess the flow ratio between each outlet, and the accurate result can be directly calculated, which is conducive to optimizing the algorithm, reducing the number of calculations, and improving the accuracy of the calculation.

[0014] Specifically, the engine cooling system includes an engine water jacket, a water pump and an auxiliary cooling mechanism. Among them, the auxiliary cooling mechanism includes a heater or a radiator. The engine water jacket has at least one water jacket inlet and at least one water jacket outlet. The water pump has a pump inlet and a pump outlet, and the pump inlet of the water pump is connected to the water jacket inlet of the engine water jacket. Furthermore, the auxiliary cooling mechanism is connected to the water jacket outlet, and the auxiliary cooling mechanism is connected to the pump inlet. The function of the engine water jacket is to transfer the heat energy of the temperature of the engine combustion chamber and the inner wall of the cylinder body to the coolant through heat conduction. Since the liquid is flowable, it circulates to the radiator through the water pump, and the radiator dissipates heat to the coolant through the flow of external air. After that, the coolant is recirculated to the engine water jacket, and the cycle continues.

[0015] Furthermore, the specific steps of the engine cooling system analysis method include:

[0016] According to the number of water jacket inlets and water jacket outlets of the engine water jacket, the engine cooling system is divided into a corresponding number of branches. The one-dimensional cooling system model is split into multiple branches;

[0017] Fit the resistance function relationship of each branch. Fit the function relationship of each branch;

[0018] The fitted functional relationship expression is used as the boundary condition of each corresponding water jacket outlet of the engine water jacket, and the internal variable calculated by iteration is associated with each iteration step;

[0019] Monitor whether the flow at the water jacket inlet is balanced. If so, it meets the requirements. If not, change the boundary conditions of the outlet with the iteration step. The flow boundaries of each inlet and outlet change with the iteration step and finally reach a balanced state. At this time, the inlet flow is the balanced flow after considering the engine water jacket resistance, water pump performance, and other pipeline losses; the flow of each outlet is the flow distribution calculated directly according to the resistance outside the water jacket outlet without relying on the assumed distribution ratio. Since the calculation process itself also includes temperature and heat transfer calculations, the boundary flow determination and the heat transfer coefficient calculation of the engine water jacket are finally realized in one calculation.

[0020] Specifically, taking the example of an engine water jacket having one inlet and two outlets, the engine cooling system includes three branches, namely: 1) water pump branch, pump inlet-pump body-pump outlet; 2) heater branch, heater branch inlet (i.e. one of the water jacket water inlets)-heater-heat branch outlet (i.e. pump inlet); 3) radiator branch, radiator branch inlet (i.e. another water jacket inlet)-radiator-radiator branch outlet (i.e. pump inlet).

[0021] Establish a one-dimensional model of the cooling system (except the water jacket) using any one-dimensional analysis software, such as FloMaster, AmeSim, etc.; or general modeling software such as Matlab; you can also manually process the simplified fitting data of each part.

[0022] The flow resistance characteristics of the above three branches are parameter-fitted, and the water pump can be directly fitted with the performance curve. The three curves are the water pump performance (solid line part), the warm air branch (dotted line part), and the radiator branch (double-dotted line part).

[0023] The specific method for parameter fitting of the warm air branch and the radiator branch is: give a series of flow rates such as 0.2, 0.4, 0.6, 0.8, 1 to the warm air branch inlet, and a fixed pressure of 0 at the warm air branch outlet. Calculate the corresponding pressure difference (i.e. water resistance) between the warm air branch inlet and outlet as 0.1, 0.3, 0.6, 0.99, 1.4. Then plot the points and draw a graph to fit the curve.

[0024] For ease of expression, the pump head function y = 0.9018x 2+0.0204x+1.1921, abbreviated as Y_head=func_Head(x); similarly, heater water resistance Y=func_heater(x); radiator water resistance Y=func_radi(x). At the same time, due to input requirements, heater water resistance needs to find the inverse function, that is, heater flow rate X=func_heater-1(y).

[0025] A heat transfer analysis model of the engine water jacket is established in a three-dimensional analysis software, such as StarCCM+, Fluent, Fire and other fluid analysis software (for example only, not limited).

[0026] Set the import and export boundary conditions in the 3D software:

[0027] Engine water inlet volume flow inlet =

[0028] (initial_flow×(Iteration<2)+InletFlow×1.1×(InletPressure<func_Head(InletFlow))+InletFlow×0.99×(InletPressure> func_Head(InletFlow)))×(InletPressue / func_Head(InletFlow)-1)>0.001)+(InletPressue / func_Head(InletFlow)-1)<=0.001)×InletFlow.

[0029] The logic and functionality of the above code are as follows:

[0030] Set the initial flow initial_flow;

[0031] Then the inlet flow rate is gradually increased by 10% with the iteration step;

[0032] If the calculated inlet pressure InletPressure is lower than the head calculated by func_Head(InletFlow), continue to increase the inlet flow by 10%;

[0033] If the calculated inlet pressure InletPressure is higher than the head calculated by func_Head(InletFlow), the inlet flow is gradually reduced by 99% of the inlet flow;

[0034] When the calculated inlet pressure InletPressure and the head calculated by func_Head(InletFlow) differ within 0.1%, the inlet flow is considered to be balanced, and the inlet flow will no longer change;

[0035] For engine heater outlet volume flow inlet =

[0036] func_Heater-1(Heater_OutletPressue).

[0037] The logic and functionality of the above code are as follows:

[0038] Directly call the pressure of the warm air branch outlet Heater_OutletPressure, and then calculate the flow of the warm air branch outlet according to the function func_Heater-1(Heater_OutletPressure);

[0039] As the number of iterations increases, the changes in the pressure at the outlet of the warm air branch and the calculated flow rate continue to decrease, and eventually the flow rate reaches a stable state.

[0040] For the engine radiator outlet: Pressure Outlet = 0; additionally set the outlet pressure loss Pressure Loss = func_Radi(Radiator_OutletFlow).

[0041] The logic and functionality of the above code are as follows:

[0042] At the outlet of the radiator branch, the water resistance loss of the radiator branch is calculated directly according to the outlet flow Radiator_OutFlow, and then the outlet flow is iteratively calculated again until the flow is balanced.

[0043] The engine water jacket surface temperature, coolant properties, and other general settings are not described.

[0044] After the calculation is completed, you can first view the flow data of each inlet and outlet to obtain the accurate flow distribution that originally required multiple cross-software iterations. Then you can view the heat transfer coefficient cloud map on the surface of the engine water jacket to evaluate the heat transfer capacity of the engine water jacket. You can also export the heat transfer coefficient and the corresponding wall temperature for other coupled calculations.

[0045] At present, when conducting three-dimensional heat transfer analysis of engine water jacket, the focus is on how to improve the calculation accuracy (using fluid-structure interaction) and improve the degree of automation (using scripts to standardize the analysis process). However, no attention is paid to the accuracy of the input boundary.

[0046] The general method to obtain the water jacket flow is as follows:

[0047] 1. When the water jacket has only a single inlet and outlet, a set of flow boundaries from small to large are directly given on the 3D CFD model of the water jacket, and the corresponding resistance is calculated respectively. Based on this, the water resistance parameters of the water jacket are generated.

[0048] Then, combined with the data of other parts of the cooling system, the water jacket flow rate is calculated through the one-dimensional cooling system model. This flow rate can be used as a boundary for the three-dimensional heat transfer analysis of the water jacket.

[0049] 2. However, when the water jacket has multiple outlets, it is still necessary to give a set of flow boundaries from small to large on the 3D CFD model of the water jacket, and then give the outlet flow distribution ratio based on the guesswork, and calculate the resistance of each outlet corresponding to each flow. Based on this, the water resistance parameters of each outlet of the water jacket are generated.

[0050] Then, combined with the data of other parts of the cooling system, the water jacket flow is calculated through the one-dimensional cooling system model. However, since the proportion of the outlet flow is guessed, it is necessary to confirm whether the outlet flow calculated by the one-dimensional cooling system is consistent with the guess. But usually it is not.

[0051] At this point, it is necessary to re-assume the flow ratio of the water jacket outlet, and then repeat the previous two steps until they match. This will consume a lot of time and energy. Therefore, there are also cases where accuracy is abandoned and the results calculated by the first round of assumptions are directly accepted. This will introduce deviations and inaccuracies to the analysis of the water jacket and the one-dimensional cooling system. When analyzing the heat transfer performance of the engine water jacket, it is actually necessary to exchange data with the one-dimensional cooling system analysis to obtain an accurate analysis boundary. Even the simplest case requires three calculations: calculation of the water jacket water resistance parameters, one-dimensional cooling system analysis, and water jacket heat transfer performance analysis. If the water jacket has more than two outlets, there are two situations: either spend time and energy on iteration, or accept inaccurate and biased results.

[0052] In the technical solution defined in the present invention, a method of decomposing, transforming and entering a one-dimensional model into a three-dimensional model is adopted to accurately calculate the balance flow in a one-time manner in the three-dimensional software. One calculation directly completes the task of at least three calculations in the past; for multiple outlets of the engine water jacket, there is no need to guess the flow ratio between each outlet, and the accurate result can be directly calculated, which is conducive to optimizing the algorithm, reducing the number of calculations, and improving the accuracy of the calculation.

[0053] In addition, the above technical solution provided by the present invention may also have the following additional technical features:

[0054] In the above technical solution, the flow balance at the water jacket inlet is monitored. If so, it meets the requirements. If not, before changing the boundary conditions of the outlet with the iteration step, it also includes: using the water pump performance curve as the boundary condition of the water jacket inlet.

[0055] In this technical solution, the water pump performance curve is used as the boundary condition of the engine water jacket inlet, and is associated with each iteration step through the internal variables of the iterative calculation. It can be understood that the water pump performance curve is connected with the functional relationship expression of other branches, so that the curves of each branch can be associated with each other.

[0056] In the above technical solution, after the water pump performance curve is used as the boundary condition of the engine water jacket inlet, it also includes: setting the temperature boundary of each position of the engine water jacket and the fluid properties in the engine water jacket.

[0057] In this technical solution, after the water pump performance curve is used as the boundary condition of the engine water jacket inlet, the engine cooling system analysis method also includes setting other boundaries. The other boundaries include the temperature boundary of each position of the engine water jacket, the inlet boundary and the fluid properties in the engine water jacket. It can be understood that bringing other parameters into the cooling system model is conducive to improving the accuracy of the calculation.

[0058] In the above technical solution, after setting the temperature boundaries of each position of the engine water jacket and the fluid properties in the engine water jacket, it also includes: calculating the heat exchange performance of the engine water jacket.

[0059] In this technical solution, after the calculation is completed, the flow data of each inlet and outlet can be checked first, so as to obtain the accurate flow distribution that originally required multiple cross-software iterations. Then, the heat transfer coefficient cloud map of the engine water jacket surface can be checked to evaluate the heat transfer capacity of the engine water jacket. The heat transfer coefficient and the corresponding wall temperature can also be derived for other coupled calculations.

[0060] In the above technical solution, before splitting the engine cooling system into a corresponding number of branches according to the number of water jacket inlets and water jacket outlets of the engine water jacket, it also includes: collecting relevant data of the engine cooling system and establishing a one-dimensional cooling system model outside the engine water jacket.

[0061] In this technical solution, before splitting the model into a corresponding number of branches according to the number of inlets and outlets of the engine water jacket, the engine cooling system analysis method also includes collecting cooling system related data and establishing a one-dimensional cooling system model outside the engine water jacket. After establishing the one-dimensional analysis model, the one-dimensional model is decomposed, converted, and entered into a three-dimensional model in subsequent steps.

[0062] In the above technical solution, the relevant data include the geometric dimensions of the pipeline, the water resistance data of the radiator and the water resistance data of the heater.

[0063] In this technical solution, the geometric dimension information of the cooling system related components and pipelines, as well as other water resistance data such as radiators and heaters are collected to establish a one-dimensional cooling system model excluding the engine water jacket.

[0064] An embodiment of the second aspect of the present invention provides a readable storage medium having instructions stored thereon, and when the instructions are executed by a processor, the steps of the engine cooling system analysis method in any of the above embodiments are implemented.

[0065] According to an embodiment of the readable storage medium of the present invention, the readable storage medium stores instructions, and when the instructions are executed by the processor, the steps of the engine cooling system analysis method in any of the above embodiments are implemented. The first step is to split the engine cooling system into a corresponding number of branches according to the number of the water jacket inlet and the water jacket outlet of the engine water jacket. The one-dimensional cooling system model is split and the model is split into multiple branches; the second step is to fit the resistance function relationship for each branch. For each branch, the function relationship is fitted; the third step is to use the fitted function relationship expression as the boundary condition of each corresponding water jacket outlet of the engine water jacket, and establish an association with each iteration step through the internal variables of the iterative calculation; the fourth step is to monitor whether the flow of the water jacket inlet is balanced, if so, it meets the requirements, otherwise, the boundary conditions of the outlet are changed with the iteration step. The flow boundaries of each inlet and outlet change continuously with the iteration step, and finally reach a balanced state. At this time, the inlet flow is the balanced flow after considering the engine water jacket resistance, water pump performance, and other pipeline losses; the flow of each outlet is the flow distribution calculated directly according to the resistance outside the water jacket outlet without relying on the assumed distribution ratio. Since the calculation process itself also includes temperature and heat transfer calculations, the boundary flow determination and the heat transfer coefficient calculation of the engine water jacket are finally achieved in one calculation.

[0066] An embodiment of the third aspect of the present invention provides an analysis device, comprising: a memory for storing a computer program; and a processor for implementing the steps of the engine cooling system analysis method in any of the above embodiments when executing the computer program.

[0067] According to an embodiment of the analysis device of the present invention, the analysis device includes a memory and a processor. Specifically, the memory is used to store a computer program, and the processor implements the steps of the engine cooling system analysis method in any of the above embodiments when executing the computer program. The first step is to split the engine cooling system into a corresponding number of branches according to the number of the water jacket inlet and the water jacket outlet of the engine water jacket. The one-dimensional cooling system model is split into multiple branches; the second step is to fit the resistance function relationship for each branch. For each branch, the function relationship is fitted; the third step is to use the fitted function relationship expression as the boundary condition of each corresponding water jacket outlet of the engine water jacket, and establish an association with each iteration step through the internal variables of the iterative calculation; the fourth step is to monitor whether the flow balance of the water jacket inlet is met, if so, it meets the requirements, otherwise, the boundary conditions of the outlet are changed with the iteration step. The flow boundaries of each inlet and outlet change continuously with the iteration step, and finally reach a balanced state. At this time, the inlet flow is the balanced flow after considering the engine water jacket resistance, water pump performance, and other pipeline losses; the flow of each outlet is the flow distribution calculated directly according to the resistance outside the water jacket outlet without relying on the assumed distribution ratio. Since the calculation process itself also includes temperature and heat transfer calculations, the boundary flow determination and the heat transfer coefficient calculation of the engine water jacket are finally achieved in one calculation.

[0068] Additional aspects and advantages of embodiments of the present invention will become apparent in the following description or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 A first schematic diagram of an engine cooling system according to an embodiment of the present invention is shown;

[0070] Figure 2 A second schematic diagram of an engine cooling system according to an embodiment of the present invention is shown;

[0071] Figure 3 A schematic diagram showing a function fitting relationship according to an embodiment of the present invention;

[0072] Figure 4 A third schematic diagram showing an engine cooling system according to an embodiment of the present invention;

[0073] Figure 5 A flow chart showing an engine cooling system analysis method according to an embodiment of the present invention is shown;

[0074] Figure 6 A flow chart showing an engine cooling system analysis method according to another embodiment of the present invention;

[0075] Figure 7A flow chart showing an engine cooling system analysis method according to another embodiment of the present invention;

[0076] Figure 8 A flow chart showing an engine cooling system analysis method according to another embodiment of the present invention;

[0077] Fig. 9 A flow chart of an engine cooling system analysis method according to another embodiment of the present invention is shown.

[0078] in, Figure 1 , Figure 2 and Figure 4 The corresponding relationship between the reference numerals and the component names is as follows:

[0079] 100: engine cooling system; 110: engine water jacket; 111: water jacket inlet; 112: water jacket outlet; 120: water pump; 121: pump inlet; 122: pump outlet; 130: auxiliary cooling mechanism; 131: heater; 132: radiator. DETAILED DESCRIPTION

[0080] In order to more clearly understand the above-mentioned purposes, features and advantages of the embodiments of the present invention, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0081] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the embodiments of the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0082] Refer to the following Figures 1 to 9 An engine cooling system analysis method, a readable storage medium, and an analysis device are described according to some embodiments of the present invention.

[0083] Embodiment 1

[0084] like Figure 1As shown, the engine cooling system includes an engine water jacket, a water pump and an auxiliary cooling mechanism. Among them, the auxiliary cooling mechanism includes a heater or a radiator. The engine water jacket has at least one water jacket inlet and at least one water jacket outlet. The water pump has a pump inlet and a pump outlet, and the pump inlet of the water pump is connected to the water jacket inlet of the engine water jacket. Furthermore, the auxiliary cooling mechanism is connected to the water jacket outlet, and the auxiliary cooling mechanism is connected to the pump inlet. The function of the engine water jacket is to transfer the heat energy of the temperature of the engine combustion chamber and the inner wall of the cylinder body to the coolant through heat conduction. Since the liquid is flowable, it circulates to the radiator through the water pump, and the radiator dissipates the heat to the coolant through the flow of external air. After that, the coolant is recirculated to the engine water jacket, and the cycle is repeated.

[0085] Furthermore, if Figure 5 As shown, the specific steps of the engine cooling system analysis method include:

[0086] Step S102, according to the number of water jacket inlets and water jacket outlets of the engine water jacket, the engine cooling system is split into a corresponding number of branches. The one-dimensional cooling system model is split into multiple branches;

[0087] Step S104, fitting the resistance function relationship of each branch. For each branch, fitting the function relationship;

[0088] Step S106, using the fitted functional relationship expression as the boundary condition of each corresponding water jacket outlet of the engine water jacket, and establishing an association with each iteration step through the internal variable of the iterative calculation;

[0089] Step S108, monitor whether the flow at the water jacket inlet is balanced, if so, it meets the requirements, if not, change the boundary conditions of the outlet with the iteration step. The flow boundaries of each inlet and outlet change continuously with the iteration step, and finally reach a balanced state. At this time, the inlet flow is the balanced flow after considering the engine water jacket resistance, water pump performance, and other pipeline losses; the flow of each outlet is the flow distribution calculated directly according to the resistance outside the water jacket outlet without relying on the assumed distribution ratio. Since the calculation process itself also includes temperature and heat transfer calculations, the boundary flow determination and the heat transfer coefficient calculation of the engine water jacket are finally realized in one calculation.

[0090] Specifically, take the example of an engine water jacket having one inlet and two outlets. Figure 2 As shown, the engine cooling system includes three branches, namely: 1) water pump branch, pump inlet-pump body-pump outlet; 2) heater branch, heater branch inlet (i.e. one of the water jacket water inlets)-heater-warm air branch outlet (i.e. pump inlet); 3) radiator branch, radiator branch inlet (i.e. another water jacket inlet)-radiator-radiator branch outlet (i.e. pump inlet).

[0091] Establish a one-dimensional model of the cooling system (except the water jacket) using any one-dimensional analysis software, such as FloMaster, AmeSim, etc.; or general modeling software such as Matlab; you can also manually process the simplified fitting data of each part.

[0092] like Figure 3 As shown, the flow resistance characteristics of the above three branches are parameter-fitted, and the water pump can be directly fitted with the performance curve. The three curves are the water pump performance (solid line part), the warm air branch (dotted line part), and the radiator branch (double-dotted line part).

[0093] The specific method for parameter fitting of the warm air branch and the radiator branch is: give a series of flow rates such as 0.2, 0.4, 0.6, 0.8, 1 to the warm air branch inlet, and a fixed pressure of 0 at the warm air branch outlet. Calculate the corresponding pressure difference (i.e. water resistance) between the warm air branch inlet and outlet as 0.1, 0.3, 0.6, 0.99, 1.4. Then plot the points and draw a graph to fit the curve.

[0094] For ease of expression, the pump head function y = 0.9018x 2 +0.0204x+1.1921, abbreviated as Y_head=func_Head(x); similarly, heater water resistance Y=func_heater(x); radiator water resistance Y=func_radi(x). At the same time, due to input requirements, heater water resistance needs to find the inverse function, that is, heater flow rate X=func_heater-1(y).

[0095] like Figure 4 As shown, a heat transfer analysis model of the engine water jacket is established in a three-dimensional analysis software, such as StarCCM+, Fluent, Fire and other fluid analysis software (for example only, not limited).

[0096] Set the import and export boundary conditions in the 3D software:

[0097] Engine water inlet volume flow inlet =

[0098] (initial_flow×(Iteration<2)+InletFlow×1.1×(InletPressure<func_Head(InletFlow))+InletFlow×0.99×(InletPressure> func_Head(InlerFlow)))×(InletPressue / func_Head(InletFlow)-1)>0.001)+(InletPressue / func_Head(InletFlow)-1)<=0.001)×InletFlow.

[0099] The logic and functionality of the above code are as follows:

[0100] Set the initial flow initial_flow;

[0101] Then the inlet flow rate is gradually increased by 10% with the iteration step;

[0102] If the calculated inlet pressure InletPressure is lower than the head calculated by func_Head(InletFlow), continue to increase the inlet flow by 10%;

[0103] If the calculated inlet pressure InletPressure is higher than the head calculated by func_Head(InletFlow), the inlet flow is gradually reduced by 99% of the inlet flow;

[0104] When the calculated inlet pressure InletPressure and the head calculated by func_Head(InletFlow) differ within 0.1%, the inlet flow is considered to be balanced, and the inlet flow will no longer change;

[0105] For engine heater outlet volume flow inlet =

[0106] func_Heater-1(Heater_OutletPressue).

[0107] The logic and functionality of the above code are as follows:

[0108] Directly call the pressure of the warm air branch outlet Heater_OutletPressure, and then calculate the flow of the warm air branch outlet according to the function func_Heater-1(Heater_OutletPressure);

[0109] As the number of iterations increases, the changes in the pressure at the outlet of the warm air branch and the calculated flow rate continue to decrease, and eventually the flow rate reaches a stable state.

[0110] For the engine radiator outlet: Pressure Outlet = 0; additionally set the outlet pressure loss Pressure Loss = func_Radi(Radiator_OutletFlow).

[0111] The logic and functionality of the above code are as follows:

[0112] At the outlet of the radiator branch, the water resistance loss of the radiator branch is calculated directly according to the outlet flow Radiator_OutFlow, and then the outlet flow is iteratively calculated again until the flow is balanced.

[0113] The engine water jacket surface temperature, coolant properties, and other general settings are not described.

[0114] After the calculation is completed, you can first view the flow data of each inlet and outlet to obtain the accurate flow distribution that originally required multiple cross-software iterations. Then you can view the heat transfer coefficient cloud map on the surface of the engine water jacket to evaluate the heat transfer capacity of the engine water jacket. You can also export the heat transfer coefficient and the corresponding wall temperature for other coupled calculations.

[0115] At present, when conducting three-dimensional heat transfer analysis of engine water jacket, the focus is on how to improve the calculation accuracy (using fluid-structure interaction) and improve the degree of automation (using scripts to standardize the analysis process). However, no attention is paid to the accuracy of the input boundary.

[0116] The general method to obtain the water jacket flow is as follows:

[0117] 1. When the water jacket has only a single inlet and outlet, a set of flow boundaries from small to large are directly given on the 3D CFD model of the water jacket, and the corresponding resistance is calculated respectively. Based on this, the water resistance parameters of the water jacket are generated.

[0118] Then, combined with the data of other parts of the cooling system, the water jacket flow rate is calculated through the one-dimensional cooling system model. This flow rate can be used as a boundary for the three-dimensional heat transfer analysis of the water jacket.

[0119] 2. However, when the water jacket has multiple outlets, it is still necessary to give a set of flow boundaries from small to large on the 3D CFD model of the water jacket, and then give the outlet flow distribution ratio based on the guesswork, and calculate the resistance of each outlet corresponding to each flow. Based on this, the water resistance parameters of each outlet of the water jacket are generated.

[0120] Then, combined with the data of other parts of the cooling system, the water jacket flow is calculated through the one-dimensional cooling system model. However, since the proportion of the outlet flow is guessed, it is necessary to confirm whether the outlet flow calculated by the one-dimensional cooling system is consistent with the guess. But usually it is not.

[0121] At this point, it is necessary to re-assume the flow ratio of the water jacket outlet, and then repeat the previous two steps until they match. This will consume a lot of time and energy. Therefore, there are also cases where accuracy is abandoned and the results calculated by the first round of assumptions are directly accepted. This will introduce deviations and inaccuracies to the analysis of the water jacket and the one-dimensional cooling system. When analyzing the heat transfer performance of the engine water jacket, it is actually necessary to exchange data with the one-dimensional cooling system analysis to obtain an accurate analysis boundary. Even the simplest case requires three calculations: calculation of the water jacket water resistance parameters, one-dimensional cooling system analysis, and water jacket heat transfer performance analysis. If the water jacket has more than two outlets, there are two situations: either spend time and energy on iteration, or accept inaccurate and biased results.

[0122] In the technical solution defined in the present invention, a method of decomposing, transforming and entering a one-dimensional model into a three-dimensional model is adopted to accurately calculate the balance flow in a one-time manner in the three-dimensional software. One calculation directly completes the task of at least three calculations in the past; for multiple outlets of the engine water jacket, there is no need to guess the flow ratio between each outlet, and the accurate result can be directly calculated, which is conducive to optimizing the algorithm, reducing the number of calculations, and improving the accuracy of the calculation.

[0123] Embodiment 2

[0124] like Figure 6 As shown, the specific steps of the engine cooling system analysis method include:

[0125] Step S202, according to the number of water jacket inlets and water jacket outlets of the engine water jacket, the engine cooling system is split into a corresponding number of branches. The one-dimensional cooling system model is split into multiple branches;

[0126] Step S204, fitting the resistance function relationship of each branch. For each branch, fitting the function relationship;

[0127] Step S206, using the fitted functional relationship expression as the boundary condition of each corresponding water jacket outlet of the engine water jacket, and establishing an association with each iteration step through the internal variable of the iterative calculation;

[0128] Step S208, using the water pump performance curve as the boundary condition of the water jacket inlet. The water pump performance curve is used as the boundary condition of the engine water jacket inlet, and is associated with each iteration step through the internal variables of the iterative calculation. It can be understood that the water pump performance curve is associated with the functional relationship expression of other branches, so that the curves of each branch can be associated with each other;

[0129] Step S210, monitor whether the flow at the water jacket inlet is balanced, if so, it meets the requirements, if not, change the boundary conditions of the outlet with the iteration step. The flow boundaries of each inlet and outlet change continuously with the iteration step, and finally reach a balanced state. At this time, the inlet flow is the balanced flow after considering the engine water jacket resistance, water pump performance, and other pipeline losses; the flow of each outlet is the flow distribution calculated directly according to the resistance outside the water jacket outlet without relying on the assumed distribution ratio. Since the calculation process itself also includes temperature and heat transfer calculations, the boundary flow determination and the heat transfer coefficient calculation of the engine water jacket are finally realized in one calculation.

[0130] Embodiment 3

[0131] like Figure 7 As shown, the specific steps of the engine cooling system analysis method include:

[0132] Step S302, according to the number of water jacket inlets and water jacket outlets of the engine water jacket, the engine cooling system is split into a corresponding number of branches. The one-dimensional cooling system model is split into multiple branches;

[0133] Step S304, fitting the resistance function relationship of each branch. For each branch, fitting the function relationship;

[0134] Step S306, using the fitted functional relationship expression as the boundary condition of each corresponding water jacket outlet of the engine water jacket, and establishing an association with each iteration step through the internal variable of the iterative calculation;

[0135] Step S308, using the water pump performance curve as the boundary condition of the water jacket inlet. The water pump performance curve is used as the boundary condition of the engine water jacket inlet, and is associated with each iteration step through the internal variables of the iterative calculation. It can be understood that the water pump performance curve is associated with the functional relationship expression of other branches, so that the curves of each branch can be associated with each other;

[0136] Step S310, setting the temperature boundary of each position of the engine water jacket and the fluid properties in the engine water jacket. Bringing other parameters into the cooling system model is conducive to improving the accuracy of the calculation;

[0137] Step S312, monitor whether the flow at the water jacket inlet is balanced, if so, it meets the requirements, if not, change the boundary conditions of the outlet with the iteration step. The flow boundaries of each inlet and outlet change continuously with the iteration step, and finally reach a balanced state. At this time, the inlet flow is the balanced flow after considering the engine water jacket resistance, water pump performance, and other pipeline losses; the flow of each outlet is the flow distribution calculated directly according to the resistance outside the water jacket outlet without relying on the assumed distribution ratio. Since the calculation process itself also includes temperature and heat transfer calculations, the boundary flow determination and the heat transfer coefficient calculation of the engine water jacket are finally realized in one calculation.

[0138] Embodiment 4

[0139] like Figure 8 As shown, the specific steps of the engine cooling system analysis method include:

[0140] Step S402, according to the number of water jacket inlets and water jacket outlets of the engine water jacket, the engine cooling system is split into a corresponding number of branches. The one-dimensional cooling system model is split into multiple branches;

[0141] Step S404, fitting the resistance function relationship of each branch. For each branch, fitting the function relationship;

[0142] Step S406, using the fitted functional relationship expression as the boundary condition of each corresponding water jacket outlet of the engine water jacket, and establishing an association with each iteration step through the internal variable of the iterative calculation;

[0143] Step S408, using the water pump performance curve as the boundary condition of the water jacket inlet. The water pump performance curve is used as the boundary condition of the engine water jacket inlet, and is associated with each iteration step through the internal variables of the iterative calculation. It can be understood that the water pump performance curve is associated with the functional relationship expression of other branches, so that the curves of each branch can be associated with each other;

[0144] Step S410, setting the temperature boundary of each position of the engine water jacket and the fluid properties in the engine water jacket. Bringing other parameters into the cooling system model is conducive to improving the accuracy of the calculation;

[0145] Step S412, calculate the heat transfer performance of the engine water jacket. After the calculation is completed, you can first check the flow data of each inlet and outlet to obtain the accurate flow distribution that originally required multiple cross-software iterations. Then you can check the heat transfer coefficient cloud map on the surface of the engine water jacket to evaluate the heat transfer capacity of the engine water jacket. You can also derive the heat transfer coefficient and the corresponding wall temperature for other coupled calculations;

[0146] Step S414, monitor whether the flow at the water jacket inlet is balanced, if so, it meets the requirements, if not, change the boundary conditions of the outlet with the iteration step. The flow boundaries of each inlet and outlet change continuously with the iteration step, and finally reach a balanced state. The inlet flow at this time is the balanced flow after considering the engine water jacket resistance, water pump performance, and other pipeline losses; the flow of each outlet is the flow distribution calculated directly according to the resistance outside the water jacket outlet without relying on the assumed distribution ratio. Since the calculation process itself also includes temperature and heat transfer calculations, the boundary flow determination and the heat transfer coefficient calculation of the engine water jacket are finally realized in one calculation.

[0147] Embodiment 5

[0148] like Fig. 9 As shown, the specific steps of the engine cooling system analysis method include:

[0149] Step S502, collecting relevant data of the engine cooling system and establishing a one-dimensional cooling system model other than the engine water jacket. The relevant data includes geometric dimensions of the pipeline, water resistance data of the radiator and water resistance data of the heater;

[0150] Step S504, splitting the engine cooling system into a corresponding number of branches according to the number of water jacket inlets and water jacket outlets of the engine water jacket. Splitting the one-dimensional cooling system model into multiple branches;

[0151] Step S506, fitting the resistance function relationship of each branch. Fitting the function relationship of each branch;

[0152] Step S508, using the fitted functional relationship expression as the boundary condition of each corresponding water jacket outlet of the engine water jacket, and establishing an association with each iteration step through the internal variable of the iterative calculation;

[0153] Step S510, the water pump performance curve is used as the boundary condition of the water jacket inlet. The water pump performance curve is used as the boundary condition of the engine water jacket inlet, and is associated with each iteration step through the internal variables of the iterative calculation. It can be understood that the water pump performance curve is associated with the functional relationship expression of other branches, so that the curves of each branch can be associated with each other;

[0154] Step S512, setting the temperature boundary of each position of the engine water jacket and the fluid properties in the engine water jacket. Bringing other parameters into the cooling system model is conducive to improving the accuracy of the calculation;

[0155] Step S514, calculate the heat transfer performance of the engine water jacket. After the calculation is completed, you can first check the flow data of each inlet and outlet to obtain the accurate flow distribution that originally required multiple cross-software iterations. Then you can check the heat transfer coefficient cloud map on the surface of the engine water jacket to evaluate the heat transfer capacity of the engine water jacket. You can also derive the heat transfer coefficient and the corresponding wall temperature for other coupled calculations;

[0156] Step S516, monitor whether the flow at the water jacket inlet is balanced, if so, it meets the requirements, if not, change the boundary conditions of the outlet with the iteration step. The flow boundaries of each inlet and outlet change continuously with the iteration step, and finally reach a balanced state. At this time, the inlet flow is the balanced flow after considering the engine water jacket resistance, water pump performance, and other pipeline losses; the flow of each outlet is the flow distribution calculated directly according to the resistance outside the water jacket outlet without relying on the assumed distribution ratio. Since the calculation process itself also includes temperature and heat transfer calculations, the boundary flow determination and the heat transfer coefficient calculation of the engine water jacket are finally realized in one calculation.

[0157] Embodiment 6

[0158] like Figure 1 , Figure 2 and Figure 4 As shown, an engine cooling system 100 provided by one embodiment of the present invention includes an engine water jacket 110, a water pump 120, an auxiliary cooling mechanism 130 and a processor 140. Among them, the auxiliary cooling mechanism 130 includes a heater 131 or a radiator 132, etc. The engine water jacket 110 has at least one water jacket inlet 111 and at least one water jacket outlet 112. The water pump 120 has a pump inlet 121 and a pump outlet 122, and the pump inlet 121 of the water pump 120 is connected to the water jacket inlet 111 of the engine water jacket 110. Further, the auxiliary cooling mechanism 130 is connected to the water jacket outlet 112, and the auxiliary cooling mechanism 130 is connected to the pump inlet 121. The function of the engine water jacket 110 is to transfer the heat energy from the temperature of the engine combustion chamber and the inner wall of the cylinder body to the coolant through heat conduction. Since the liquid is flowable, it circulates to the radiator 132 through the water pump 120, and the radiator 132 dissipates the heat of the coolant through the flow of external air. The coolant then circulates to the engine water jacket 110, and the cycle continues.

[0159] Further, the number of the water jacket inlet 111 is one, and the number of the water jacket outlet 112 is two. The engine cooling system 100 includes three branches, that is, the one-dimensional model is split into three branches.

[0160] Furthermore, the auxiliary cooling mechanism 130 includes: a heater 131, the heater 131 is connected to one of the water jacket outlets 112, and the heater 131 is connected to the pump inlet 121; a radiator 132, the radiator 132 is connected to the other water jacket outlet 112, and the radiator 132 is connected to the pump inlet 121. The engine cooling system 100 includes three branches. Specifically, the three branches are: 1) water pump 120 branch, pump inlet 121-pump body-pump outlet 122; 2) heater 131 branch, warm air branch inlet (i.e. one of the water jacket water inlets)-heater 131-warm air branch outlet (i.e. pump inlet 121);

[0161] 3) Radiator 132 branch, radiator 132 branch inlet (ie, another water jacket inlet 111) - radiator 132 - radiator 132 branch outlet (ie, pump inlet 121).

[0162] Embodiment 7

[0163] A readable storage medium provided by an embodiment of the present invention stores instructions, and when the instructions are executed by a processor, the steps of the engine cooling system analysis method in any of the above embodiments are implemented. The first step is to split the engine cooling system into a corresponding number of branches according to the number of water jacket inlets and water jacket outlets of the engine water jacket. The one-dimensional cooling system model is split into multiple branches; the second step is to fit the resistance function relationship for each branch. For each branch, the function relationship is fitted; the third step is to use the fitted function relationship expression as the boundary condition of each corresponding water jacket outlet of the engine water jacket, and establish an association with each iteration step through the internal variables of iterative calculation; the fourth step is to monitor whether the flow of the water jacket inlet is balanced, if so, it meets the requirements, otherwise, the boundary conditions of the outlet are changed with the iteration step. The flow boundaries of each inlet and outlet change continuously with the iteration step, and finally reach a balanced state. At this time, the inlet flow is the balanced flow after considering the engine water jacket resistance, water pump performance, and other pipeline losses; the flow of each outlet is the flow distribution calculated directly according to the resistance outside the water jacket outlet without relying on the assumed distribution ratio. Since the calculation process itself also includes temperature and heat transfer calculations, the boundary flow determination and the heat transfer coefficient calculation of the engine water jacket are finally achieved in one calculation.

[0164] Embodiment 8

[0165] An analysis device provided by an embodiment of the present invention includes a memory and a processor. Specifically, the memory is used to store a computer program, and the processor implements the steps of the engine cooling system analysis method in any of the above embodiments when executing the computer program. In the first step, the engine cooling system is divided into a corresponding number of branches according to the number of water jacket inlets and water jacket outlets of the engine water jacket. The one-dimensional cooling system model is split into multiple branches; in the second step, the resistance function relationship is fitted for each branch. For each branch, the function relationship is fitted; in the third step, the fitted function relationship expression is used as the boundary condition of each corresponding water jacket outlet of the engine water jacket, and an association is established with each iteration step through the internal variables of iterative calculation; in the fourth step, whether the flow of the water jacket inlet is balanced is monitored, if so, it meets the requirements, otherwise, the boundary conditions of the outlet are changed with the iteration step. The flow boundaries of each inlet and outlet change continuously with the iteration step, and finally reach a balanced state. At this time, the inlet flow is the balanced flow after considering the engine water jacket resistance, water pump performance, and other pipeline losses; the flow of each outlet is the flow distribution calculated directly according to the resistance outside the water jacket outlet without relying on the assumed distribution ratio. Since the calculation process itself also includes temperature and heat transfer calculations, the boundary flow determination and the heat transfer coefficient calculation of the engine water jacket are finally achieved in one calculation.

[0166] According to the embodiment of the engine cooling system analysis method, readable storage medium and analysis device of the present invention, the method of decomposing, converting and entering the one-dimensional model into the three-dimensional model is adopted to accurately calculate the balance flow in one time in the three-dimensional software. One calculation directly completes the calculation task of at least three times in the past; for multiple outlets of the engine water jacket, it is no longer necessary to guess the flow ratio between each outlet, and the accurate result can be directly calculated, which is conducive to optimizing the algorithm, reducing the number of calculations, and improving the accuracy of the calculation.

[0167] In the present invention, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0168] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “front” and “back” are based on the directions 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 unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0169] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0170] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An engine cooling system analysis method, It is characterized in that include: According to the number of water jacket inlets and water jacket outlets of the engine water jacket, the engine cooling system is divided into corresponding number of branches; Fitting a resistance function relationship for each branch; The fitted functional relationship expression is used as the boundary condition of each corresponding water jacket outlet, and an internal variable of iterative calculation is associated with each iteration step; Monitor whether the flow rate of the water jacket inlet is balanced, if so, it meets the requirements, if not, change the boundary conditions of the outlet with the iteration step; Using the water pump performance curve as the boundary condition of the water jacket inlet; After the water pump performance curve is used as the boundary condition of the water jacket inlet, it also includes: Setting temperature boundaries at various positions of the engine water jacket and fluid properties in the engine water jacket; The flow rate of each outlet is distributed according to the flow rate calculated by the resistance outside the water jacket outlet, and the calculation process includes temperature and heat transfer calculation; After setting the temperature boundaries of each position of the engine water jacket and the fluid properties in the engine water jacket, the method further includes: Calculating the heat transfer performance of the engine water jacket; After the calculation is completed, check the flow data of each inlet and outlet to obtain the flow distribution, then check the heat transfer coefficient cloud map on the surface of the engine water jacket to evaluate the heat transfer capacity of the engine water jacket, and derive the heat transfer coefficient and the corresponding wall temperature for other coupled calculations.

2. The engine cooling system analysis method according to claim 1, It is characterized in that According to the number of water jacket inlets and water jacket outlets of the engine water jacket, before the engine cooling system is divided into a corresponding number of branches, it also includes: Relevant data of the engine cooling system are collected, and a one-dimensional cooling system model outside the engine water jacket is established.

3. The engine cooling system analysis method according to claim 2, It is characterized in that The relevant data include geometrical dimensions of the pipeline.

4. The engine cooling system analysis method according to claim 3, It is characterized in that The relevant data also includes water resistance data of the radiator.

5. The engine cooling system analysis method according to claim 4, It is characterized in that The related data also includes water resistance data of the heater.

6. A readable storage medium having instructions stored thereon, It is characterized in that When the instructions are executed by a processor, the steps of the engine cooling system analysis method according to any one of claims 1 to 5 are implemented.

7. An analytical device, It is characterized in that include: Memory for storing computer programs; A processor, configured to implement the steps of the engine cooling system analysis method according to any one of claims 1 to 5 when executing the computer program.

Images