A method of modeling an engine thermal management system

Abstract

This invention discloses a modeling method for an engine thermal management system, comprising the following steps: determining the composition of the engine thermal management system; determining the connection sequence of each component of the engine thermal management system; selecting appropriate libraries and components in the software; selecting and setting the engine model; selecting and setting the thermostat model; selecting and setting the water pump model; selecting and setting the expansion tank model; selecting the HEAT plugin icon; selecting and setting the radiator model; selecting and setting the electronically controlled silicone oil clutch fan model; setting vehicle and environmental parameters; and setting the effect of different vehicle speeds on the radiator's heat dissipation performance. This invention simultaneously uses models from both the cooling system library and the HEAT library to model the components in the engine thermal management system. Compared with modeling using only the cooling system library, this allows for more complex control strategies and higher accuracy, laying the foundation for further research on engine thermal management systems.

Description

Technical Field

[0001] This invention relates to the field of engine thermal management system modeling and optimization, and to a method for modeling individual components and the thermal management system based on the performance parameters of thermal management system parts. In particular, it relates to a modeling method for engine thermal management systems. Background Technology

[0002] Thermal management technology is one of the key technologies in traditional gasoline-powered vehicles, directly affecting the vehicle's power and fuel economy. Engine thermal management technology takes a holistic approach, integrating heat dissipation-related components into a unified system. It then considers the heat exchange relationships between these components, combining control theory and system management methods to control and optimize heat transfer, thereby ensuring efficient and safe vehicle operation, improving fuel economy, and reducing emissions.

[0003] The research and optimization of thermal management technology are inseparable from the modeling of thermal management systems. Modeling methods for thermal management systems include one-dimensional modeling and three-dimensional modeling. While three-dimensional modeling offers higher accuracy and more intuitive results, the modeling process is extremely complex and consumes significant computational resources. Therefore, one-dimensional modeling is more commonly used in practical engineering applications.

[0004] In the past, when using modeling software to model engine thermal management systems, the pre-built cooling system library in the software was often used alone, and key parameters were often simplified using empirical coefficients. This resulted in low accuracy of the engine thermal management system model, making it difficult to match the actual situation. Therefore, it is necessary to improve the traditional modeling method to obtain a model that can provide guidance for related research.

[0005] The cooling fan is one of the most important components of an engine cooling system, and its performance and operating speed directly affect the engine's operating state. In actual engine cooling systems, the cooling fan is connected to the engine via mechanical transmission or a silicone oil clutch. With the development of automotive technology, the use of silicone oil clutches, especially electronically controlled silicone oil clutches, to drive cooling fans is becoming increasingly common. However, current modeling methods for electronically controlled silicone oil clutches in thermal management system models are not perfect. Therefore, researching modeling methods for engine thermal management systems that include electronically controlled silicone oil clutches and fans has significant research and engineering application implications.

[0006] Chinese invention patent CN114239133A discloses a "One-Dimensional Co-simulation Modeling Method for Thermal Management Systems of Hybrid Electric Vehicles." In the process of modeling engine thermal management systems, existing technologies do not consider the connection between the cooling fan and the engine. In fact, in commercial vehicle cooling systems, the electronically controlled silicone oil clutch, as a crucial component connecting the engine and the cooling fan, is responsible for transmitting engine torque to the cooling fan. Its control strategy affects the operating speed of the cooling fan, thereby influencing the performance of the engine thermal management system. Therefore, researching the modeling of electronically controlled silicone oil clutches in engine thermal management systems is of great significance. Summary of the Invention

[0007] This invention utilizes mechatronics modeling software to establish a simulation model of an engine thermal management system. It primarily uses the cooling system library and the HEAT library to select basic components, and introduces the important parameters of each component and the methods for setting up the components using these parameters. Specifically, modeling methods are established for components such as the engine, thermostat, water pump, expansion tank, radiator, and electronically controlled silicone oil clutch fan assembly. Based on the influence of vehicle speed on radiator cooling performance, a function expression applied to the heat dissipation module is established. This invention provides a reference for the optimized design of engine thermal management systems and can be used to study improvements in electronically controlled silicone oil clutch control strategies or the matching problems between cooling system components.

[0008] To achieve the objectives of this invention, a modeling method for an engine thermal management system is provided, comprising the following steps:

[0009] (1) Determine the composition of the engine thermal management system: Based on the specific structure of the vehicle, determine the components involved in the engine thermal management system. In the specific modeling process, it is necessary to ignore components that have no significant impact on the thermal management system, thereby simplifying the model and highlighting the influence of the main components.

[0010] (2) Determine the connection sequence of the components of the engine thermal management system: The main components of the engine thermal management system include the engine, water pump, thermostat, radiator, expansion tank, radiator, and electronically controlled silicone oil clutch fan assembly. The coolant flow path needs to be divided into a large circulation loop and a small circulation loop based on the connection configuration of the engine cooling system. The connection sequence between the components of the large and small circulation loops should be determined according to the layout of the cooling system.

[0011] (3) Select the appropriate libraries and components in the mechatronics modeling software: The components and connection sequence of the cooling system were determined in (2). Select the libraries that contain the components in (2) in the modeling software. The alternative libraries include: Signal and Control library, Thermal Hydraulic library, Cooling System library, and HEAT library.

[0012] (4) Engine Model Selection and Setup: Select an engine model from the Cooling System library. Model CSEN00 can be used to represent a general fuel engine. Refer to the technical parameters provided by the engine manufacturer or obtain the relationship between heat dissipation (kW), engine speed (rpm), and main shaft power (kW) through vehicle testing and engine test bench testing. Then, obtain a two-dimensional table representing the heat dissipation between the engine and the coolant. Input this table into the model to complete the engine model setup.

[0013] (5) Selection and setting of thermostat model: Select a thermostat model from the Cooling System library. Model CSTHT020 can be used to represent a simple wax thermostat. Set the relationship between the thermostat opening coefficient and the coolant temperature according to the specific thermostat component parameters.

[0014] (6) Selection and Setting of Water Pump Model: Select a water pump model from the Cooling System library. Model CSCP100 can be used to represent a simple mechanical water pump. Specify the ratio of water pump speed to engine speed based on the actual vehicle conditions. Obtain the water pump performance curve through testing according to the technical parameters provided by the component manufacturer or reference standard JB / T8126.2-1999. This curve describes the increase in pressure (bar) and flow rate (kg / m³) of the fluid after passing through the water pump at different speeds (rpm). 3 The relationship between the curves is determined by inputting this curve into the model to complete the setup of the water pump model.

[0015] (7) Selection and setup of the expansion tank model: Select the expansion tank model in the Thermal Hydraulic system. Model TFAC000 can be used to represent a simple expansion tank. Determine the volume of the expansion tank, input this parameter into the model, and complete the setup of the expansion tank model.

[0016] (8) Selecting the HEAT plugin icon: Select HEAT11 from the HEAT library and configure the external boundary conditions. Refer to step (12) for specific external flow boundary condition settings.

[0017] (9) Selection and Setting of Radiator Model: Select a radiator model from the HEAT library. The HEATRAD2001 model can be used to represent a simple water-cooled radiator. Set the radiator dimensions, cooling pipe arrangement, number and rows of cooling pipes, and cross-sectional area of ​​the cooling pipes according to the specific radiator shape parameters. Conduct radiator performance tests according to the technical parameters provided by the component manufacturer or with reference to standard JB / T2293-1978 to obtain the radiator's heat transfer performance parameters, water resistance parameters, and air resistance parameters. Based on the above parameters, obtain the pressure drop (mbar) curves of the coolant passing through the radiator at different flow rates (L / h), and the pressure drop (mbar) curves at different flow rates (mbar) 3 The pressure drop (Pa) curves of air passing through the radiator at a given pressure ( / s) are used as inputs into the model as internal and external flow parameters, respectively. The heat transfer coefficient is obtained by inputting experimental data using the built-in heat transfer parameter preprocessing program (Preprocessing Tool for HEAT library exchangers App) in the modeling software. For older versions, the heat transfer coefficient can also be calculated using semi-empirical formulas.

[0018]

[0019] in,

[0020] k m —The thermal conductivity of the radiator pipes;

[0021] —These are the mass flow rates of coolant and air, respectively;

[0022] a air b air —Air-side convection correction factor;

[0023] a f b f —Water-side convection correction factor;

[0024] (10) Selection and setup of the fan model for the electronically controlled silicone oil clutch: Select a fan model from the HEAT library. Model HEATFAN001 can be used as a representative fan. Specify the fan's diameter and thickness based on its external parameters. Obtain aerodynamic performance parameters through testing based on the technical parameters provided by the component manufacturer or by referring to standard JB / T6723.4-2008, or obtain the fan's aerodynamic performance curve through CFD three-dimensional simulation. The fan's aerodynamic performance parameters mainly include the fan's static pressure flow rate curve and efficiency flow rate curve. Input both into the model to complete the fan model setup.

[0025] After setting up the cooling fan, model the electronically controlled silicone oil clutch. In the Signal and Control library, select model FX00, which can be used as a function input, to input the piecewise function expressing the control strategy. The radiator outlet coolant temperature, related to the control strategy, is read by temperature sensor TFTS00. In the Cooling System library, select the engine speed reading module CSDATA000 to represent the engine speed. Multiply the engine speed by the control strategy function to obtain the fan speed output by the electronically controlled silicone oil clutch under a specific control strategy. Connect this result to the fan model HEATFAN001. The modeling of the electronically controlled silicone oil clutch fan assembly is now complete.

[0026] (11) Setting of vehicle and environmental parameters

[0027] Select models related to vehicle parameter settings from the Cooling System library, including: Duty Cycle Sub-model (CSED0), Engine Speed ​​and Power Calculation Model (CSCE0), and Driving Condition Definition Model (CSMP1).

[0028] The duty cycle sub-model CSED0 is used to define the ambient temperature (degC) and absolute pressure (bar), and can define the environmental parameters for multiple stages and the duration of each stage.

[0029] The engine speed and power calculation model CSCE0 is used to calculate engine speed. The setup requires specifying the vehicle's total mass, tire pressure, reference engine speed, maximum engine speed, vehicle speed at different gearbox ratios while running at the reference engine speed, and maximum spindle power at different engine speeds. These parameters can be obtained through basic vehicle information and simple vehicle tests.

[0030] The formula used to calculate engine speed is:

[0031]

[0032] in:

[0033] N mot —Actual engine speed;

[0034] N ref —Refer to engine speed;

[0035] v — Actual vehicle speed;

[0036] v ref —Vehicle speed at engine speed;

[0037] The driving condition definition model CSMP1 defines the vehicle speed, transmission gear, and road gradient during the simulation. This model can specify multiple stages and the duration of each stage.

[0038] (12) Demonstrating the impact of different vehicle speeds on radiator heat dissipation performance

[0039] The heat dissipation performance of the radiator varies at different vehicle speeds. To reflect this effect, a function expression is used in front of the HEAT11 plugin to represent the influence of different vehicle speeds on the intake pressure in front of the radiator. This function expression can be determined through whole vehicle testing or three-dimensional CFD simulation.

[0040] (13) Input multiple operating conditions, test run the established engine thermal management system model, obtain simulation calculation results under multiple operating conditions, judge the reliability of the results, and complete the modeling of the engine thermal management system.

[0041] Compared with the prior art, the present invention has at least the following positive effects:

[0042] 1) The modeling method for the electronically controlled silicone oil clutch fan assembly in the engine thermal management system model has been improved. Existing engine thermal management system modeling methods generally do not consider the connection between the cooling fan and the engine, meaning the electronically controlled silicone oil clutch component is not taken into account. This invention establishes a model of the electronically controlled silicone oil clutch component using tools such as temperature sensors, speed sensors, and mathematical functions included in mechatronics software. This model can input control strategies through mathematical functions.

[0043] 2) Models from both the cooling system library and the HEAT library were used to model the components in the engine thermal management system. Compared with modeling using only the cooling system library, this approach can achieve more complex control strategies and has higher accuracy, laying the foundation for further research on the engine thermal management system.

[0044] 3) In the settings of engine thermal management system components, using multidimensional charts or multidimensional functions to input performance parameters has higher accuracy and is more in line with actual working conditions compared with setting parameters using empirical coefficients.

[0045] 4) The impact of vehicle speed on radiator heat dissipation performance was taken into account, laying the foundation for subsequent related research.

[0046] 5) The engine thermal management system model established by the mechatronics software of this invention can correspond to the actual vehicle (including the electronically controlled silicone oil clutch). After the correctness verification, the engine thermal management system model can replace the vehicle operation test and facilitate the relevant research on engine cooling system components, reducing the economic and time costs in the product development process.

[0047] 6) The present invention provides a modeling method for an engine thermal management system, which includes modeling of an electronically controlled silicone oil clutch, enabling a more accurate representation of the relationships between components in the engine cooling system. Furthermore, the present invention includes a module demonstrating the influence of vehicle speed on the intake pressure in front of the radiator. Adding this module makes the established engine thermal management system more realistic, allowing the model to be used for thermal management simulations under various operating conditions. Attached Figure Description

[0048] Figure 1 This is a flowchart of a modeling method for an engine thermal management system provided in an embodiment of the present invention;

[0049] Figure 2 This is a simplified model of the engine thermal management system created using mechatronics modeling software;

[0050] Figure 3(a) is a schematic diagram of the two-dimensional chart used to define engine heat dissipation.

[0051] Figure 3(b) is a schematic diagram of the relationship between the thermostat opening coefficient and the coolant temperature.

[0052] Figure 3(c) is a schematic diagram of the pump performance curve used to define the performance of the pump;

[0053] Figure 3(d) is a schematic diagram of the cooling water pressure drop curve used to define the water resistance of the radiator;

[0054] Figure 3(e) is a schematic diagram of the air pressure drop curve used to define the air resistance of the radiator;

[0055] Figure 3(f) is a schematic diagram of the preprocessing interface for calculating the semi-empirical heat transfer coefficient of the radiator;

[0056] Figure 3(g) is a schematic diagram used to define the total pressure of the fan as a function of flow rate;

[0057] Figure 3(h) is a schematic diagram used to define the efficiency of a fan as a function of airflow.

[0058] Figure 4 It is a schematic diagram of the reference vehicle speed used to define different gears;

[0059] Figure 5 This is a diagram illustrating the settings in the HEAT11 plugin to show the impact of vehicle speed.

[0060] Figure 6 This is a schematic diagram of the electronically controlled silicone oil clutch fan assembly. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to the accompanying drawings and examples.

[0062] Please see Figure 1 The present invention provides a method for establishing an engine thermal management system model using mechatronics modeling software, comprising the following steps:

[0063] (1) Determine the composition of the engine thermal management system.

[0064] Based on the specific structure of the vehicle, the components involved in the engine thermal management system are determined. In the specific modeling process, components with insignificant impact on the thermal management system are ignored, thereby simplifying the model and highlighting the influence of the main components. In some embodiments of the present invention, based on the specific structure of a certain fuel-powered vehicle, the components of the engine thermal management system are determined to include: engine, thermostat, radiator, expansion tank, electronically controlled silicone oil clutch fan, and water pump.

[0065] (2) Determine the connection sequence of each component of the engine thermal management system.

[0066] Based on the connection configuration of the engine cooling system, the coolant flow path is divided into a large circulation loop and a small circulation loop. The connection sequence between the components of the large and small circulation loops is determined according to the layout of the cooling system. In some embodiments of this invention, the components traversed by the small circulation loop are: engine and water pump. The components traversed by the large circulation loop are: water pump, engine, thermostat, expansion tank, and radiator.

[0067] (3) Select the appropriate libraries and components in the mechatronics modeling software.

[0068] In some embodiments of the present invention, the components and connection sequence of the cooling system are determined in step (2), and a library containing each component from step (2) is selected in the modeling software. Alternative libraries include: Signal and Control library, Thermal Hydraulic library, Cooling System library, and HEAT library. These libraries represent the integrated functions of the mechatronics software. Only the components to be modeled need to be determined, and the appropriate library can be selected.

[0069] (4) Selection and setup of engine model:

[0070] Select an engine model from the Cooling System library, refer to the technical parameters provided by the engine manufacturer or obtain the relationship between heat dissipation (KW) and engine speed (rpm) and main shaft power (KW) through vehicle testing and engine test bench testing, and then obtain a two-dimensional table representing the heat dissipation between the engine and the coolant. Input this table into the model to complete the engine model setup.

[0071] In some embodiments of the present invention, the selected model designation is CSEN00, which can be used to represent a general internal combustion engine. The relationship between heat dissipation (kW), engine speed (rpm), and main shaft power (kW) is determined using technical parameters provided by the engine manufacturer. This relationship is input using a two-dimensional table, and the corresponding image is shown in Figure 3(a).

[0072] In some embodiments of the present invention, since the heat exchange between the engine and the cooling system is difficult to calculate precisely, a preliminary estimate is made using empirical formulas:

[0073]

[0074] in:

[0075] Q w —Heat exchange between the engine and the cooling system;

[0076] A – The percentage of heat transferred to the cooling system relative to the fuel's thermal energy; for gasoline engines, this is 0.20–0.27, and for diesel engines, it is 0.16–0.23.

[0077] g e — Fuel consumption rate of internal combustion engines (kJ / (kW·s));

[0078] h u —Low calorific value of fuel (kJ / kg).

[0079] (5) Selection and setting of thermostat model:

[0080] Select the thermostat model in the Cooling System library, and set the relationship between the thermostat opening coefficient and the coolant temperature according to the specific thermostat component parameters.

[0081] In some embodiments of the present invention, the selected model is designated CSHHT020, which can be used to represent a simple wax-type thermostat. The relationship between the thermostat opening coefficient and the coolant temperature (degC) is set according to the specific thermostat component parameters, as shown in Figure 3(b).

[0082] (6) Selection and setting of the water pump model:

[0083] Select a water pump model from the Cooling System library and specify the ratio of water pump speed to engine speed based on the actual vehicle conditions. Obtain the water pump performance curve through testing according to the technical parameters provided by the component manufacturer or reference standard JB / T8126.2-1999. This curve describes the increase in pressure (bar) and flow rate (kg / m³) of the fluid passing through the water pump at different speeds (rpm). 3 The relationship between the curves is determined by inputting this curve into the model to complete the setup of the water pump model.

[0084] In some embodiments of the present invention, the selected model is designated CSCP100. The ratio of water pump speed to engine speed is given as 1.722 based on actual vehicle installation conditions. A water pump performance curve is provided according to the technical parameters provided by the water pump manufacturer, used to represent the pressure (bar) rise and flow rate (kg / m³) of the fluid after passing through the water pump at different speeds (rpm). 3 The relationship between the curves is shown in Figure 3(c).

[0085] (7) Selection and setup of the expansion tank model:

[0086] Select the expansion tank model in the Thermal Hydraulic system, determine the volume of the expansion tank, input this parameter into the model, and complete the setup of the expansion tank model.

[0087] In some embodiments of the invention, the selected model designation is TFAC000, which can be used to represent a simple expansion tank. Refer to the default option.

[0088] (8) HEAT plugin icon:

[0089] Select HEAT11 from the HEAT library and configure the external boundary conditions. Refer to step (12) for specific settings of the external flow boundary conditions. In step (12), set up a module that reflects the effect of different vehicle speeds on the intake pressure in front of the radiator. This module contains the input of a function to express the effect of different vehicle speeds on the intake pressure in front of the radiator.

[0090] In some embodiments of the present invention, the selected model is designated HEAT11, and this will be implemented later.

[0091] (9) Selection and setting of radiator model:

[0092] Select a radiator model from the HEAT library. Set the radiator dimensions, cooling pipe arrangement, number and rows of cooling pipes, and cross-sectional area based on the specific radiator shape parameters. Conduct radiator performance tests according to the technical parameters provided by the component manufacturer or referring to standard JB / T2293-1978 to obtain the radiator's heat transfer performance parameters, water resistance parameters, and air resistance parameters. Based on these parameters, obtain the coolant pressure drop (mbar) curves through the radiator at different flow rates (L / h). 3 The pressure drop (Pa) curves of air passing through the radiator at a given pressure ( / s) are used as inputs into the model as internal and external flow parameters, respectively. The heat transfer coefficient is obtained by inputting experimental data using the preprocessing tool for HEAT library exchangers App built into the electromechanical-hydraulic modeling software. If the software version is older, the heat transfer coefficient can also be calculated using a semi-empirical formula.

[0093]

[0094] in,

[0095] k m —The thermal conductivity of the radiator pipes;

[0096] —These are the mass flow rates of coolant and air, respectively;

[0097] a air b air —Air-side convection correction factor;

[0098] a f b f —Water-side convection correction factor;

[0099] In some embodiments of the present invention, the selected model is designated HEATRAD2001, which can be used to represent a simple water-cooled radiator. Based on the radiator's structural parameters, the external dimensions are given as 0.77m * 0.458m * 0.07m, the number of flow channels is 2, and the number of pipes within the flow channels is 40. Water resistance parameters, air resistance parameters, and heat transfer parameters are given according to the technical parameters provided by the manufacturer, and the input curves are shown in Figures 3(d), 3(e), and 3(f), respectively.

[0100] (10) Selection and settings of the fan model:

[0101] Select a fan model from the HEAT library and specify the fan's diameter and thickness based on its external parameters. Obtain aerodynamic performance parameters through testing based on the technical parameters provided by the component manufacturer or by referring to standard JB / T6723.4-2008, or obtain the fan's aerodynamic performance curves through CFD 3D simulation. The fan's aerodynamic performance parameters mainly include the fan's static pressure-flow rate curve and efficiency-flow rate curve. Input these two parameters into the model to complete the fan model setup. The following formulas are used to calculate the fan's aerodynamic performance:

[0102]

[0103] in:

[0104] N—Power consumed by the fan;

[0105] T – Fan torque;

[0106]

[0107] in:

[0108] η se —Static pressure efficiency;

[0109] q — Fan flow rate;

[0110] p sp —Fan static pressure;

[0111] After completing the cooling fan setup, the electronically controlled silicone oil clutch is modeled. The electronically controlled silicone oil clutch is the transmission component connecting the cooling fan and the engine; the cooling fan assembly driven by the electronically controlled silicone oil clutch is called the electronically controlled silicone oil clutch fan. The electronically controlled silicone oil clutch incorporates a control strategy for the cooling fan speed. The relevant modules in the Signal and Control library of the modeling software are used to complete the modeling of the electronically controlled silicone oil clutch, and the control strategy is input. In some embodiments of this invention, the model FX00, which can be used as a function input, is selected in the Signal and Control library to input a piecewise function expressing the control strategy. The radiator outlet coolant temperature related to the control strategy is read by the temperature sensor TFTS00. The engine speed reading module CSDATA000 is selected in the Cooling System library to represent the engine speed. The engine speed is multiplied by the control strategy function to obtain the fan speed output by the electronically controlled silicone oil clutch under a certain control strategy. This result is then connected to the fan model HEATFAN001. The modeling of the electronically controlled silicone oil clutch fan assembly is completed.

[0112] In some embodiments of the present invention, the engine thermal management system is built based on a vehicle that includes a defined electronically controlled silicone oil clutch control strategy, which can be input during modeling.

[0113] In some embodiments of the present invention, the selected model designation is HEATFAN001, which can be used to represent a cooling fan. The given fan diameter is 620 mm. Based on the aerodynamic performance curves provided by the manufacturer, the total pressure-flow rate curve and efficiency-flow rate curve of the fan are input at a reference speed of 2100 rpm. The input curves are shown in Figures 3(g) and 3(h).

[0114] (11) Setting vehicle and environmental parameters:

[0115] Select models related to vehicle parameter settings from the cooling system library, including: Duty Cycle Sub-Model (CSED0), Engine Speed ​​and Power Calculation Model (CSCE0), and Driving Condition Definition Model (CSMP1). The Duty Cycle Sub-Model CSED0 defines the ambient temperature (degC) and absolute pressure (bar), and can define environmental parameters for multiple stages and the duration of each stage. The Engine Speed ​​and Power Calculation Model CSCE0 calculates engine speed. Its settings require specifying the vehicle's total mass, tire pressure, reference engine speed, maximum engine speed, vehicle speed at different transmission ratios while running at the reference engine speed, and maximum spindle power at different engine speeds. These parameters can be obtained through basic vehicle information and simple vehicle tests.

[0116] The formula used to calculate engine speed is:

[0117]

[0118] in:

[0119] N mot —Actual engine speed;

[0120] N ref —Refer to engine speed;

[0121] v — Actual vehicle speed;

[0122] v ref —Vehicle speed at engine speed;

[0123] The driving condition definition model CSMP1 defines the vehicle speed, transmission gear, and road gradient during the simulation. This model can specify multiple stages and the duration of each stage.

[0124] In some embodiments of the present invention:

[0125] The duty cycle sub-model is selected as CSED0, and the default option is used in this example.

[0126] The ambient air model is selected as PNGD00 to define the air characteristics of the environment; the default setting is maintained in this example.

[0127] The coolant model selected is TFFD3, which is used to define the characteristics of the coolant in the pipeline. In this example, the coolant EG40W60 is selected.

[0128] The vehicle parameter definition model CSES0 is used to define the basic characteristics of the vehicle. In this example, the engine idle speed is set to 800 rpm, the maximum speed to 4500 rpm, the vehicle weight to 7000 kg, and the reference engine speed to 1000 rpm. The settings for the reference vehicle speed for different gears are as follows... Figure 4 As shown.

[0129] (12) Demonstrating the impact of different vehicle speeds on radiator heat dissipation performance:

[0130] The heat dissipation performance of the radiator varies at different vehicle speeds. To reflect this effect, a function expression is used in front of the HEAT11 heat pipe to represent the influence of different vehicle speeds on the intake pressure in front of the radiator. This function expression can be determined through whole vehicle testing or three-dimensional CFD simulation.

[0131] The function expression is:

[0132] P = P0 + v·η

[0133] in:

[0134] P - Intake pressure in front of the radiator at a certain vehicle speed;

[0135] P0—Intake pressure in front of the radiator when the vehicle is stationary;

[0136] v — vehicle speed;

[0137] η—Characteristic coefficient of the front of the vehicle, which can be determined by experimental or CFD simulation calculation;

[0138] In some embodiments of the present invention, a function expression is set before HEAT11 to express the effect of vehicle speed on the intake pressure in front of the radiator, such as... Figure 5 As shown. Figure 5 In the HEAT Stack plugin, the part before the input indicates the intake air temperature and pressure in front of the radiator. The intake air temperature in front of the radiator is input as the current temperature, and the intake air pressure in front of the radiator is input as a function expression. This intake air pressure is related to the vehicle speed. The part after the input indicates the temperature and pressure behind the cooling fan, which are input as the current ambient temperature and ambient air pressure.

[0139] (13) Input multiple operating conditions, test run the established engine thermal management system model, obtain simulation calculation results under multiple operating conditions, judge the reliability of the results, and complete the modeling of the engine thermal management system.

[0140] In some embodiments of the present invention, the electronically controlled silicone oil clutch is modeled, and the control strategy is input in the form of a piecewise function, such as... Figure 6 As shown. Figure 6 This paper introduces a modeling method for an electronically controlled silicone oil clutch. The part between the engine and the cooling fan is the electronically controlled silicone oil clutch. The engine outlet coolant temperature sensor is responsible for identifying the engine outlet coolant temperature. Based on the input control strategy, the slip ratio is selected according to different engine outlet coolant temperatures. The cooling fan speed is obtained by multiplying the slip ratio by the engine speed. This speed is then applied to the cooling fan, completing the modeling of the electronically controlled silicone oil clutch.

[0141] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A modeling method for an engine thermal management system, characterized in that, Includes the following steps: (1) Determine the composition of the engine thermal management system; (2) Determine the connection sequence of each component of the engine thermal management system; (3) Select the appropriate libraries and components in the mechatronics modeling software; (4) Selection and setting of engine model: Select engine model in the cooling system library, refer to the technical parameters provided by the engine manufacturer or obtain the relationship between heat dissipation and engine speed and main shaft power through vehicle test and engine test bench test, and then obtain a two-dimensional table representing the heat dissipation between engine and coolant. Input this table into the model to complete the setting of engine model. (5) Selection and setting of thermostat model: Select thermostat model in the cooling system library, and set the relationship between thermostat opening coefficient and coolant temperature according to the specific thermostat component parameters; (6) Selection and setting of water pump model: Select water pump model in the cooling system library, give the ratio of water pump speed to engine speed according to the actual vehicle conditions, conduct experiments to obtain water pump performance curve, input this curve into the model, and complete the setting of water pump model. (7) Selection and setting of expansion tank model: Select expansion tank model in thermal hydraulic reservoir, determine the volume of expansion tank, input this parameter into model, and complete the setting of expansion tank model; (8) Selecting the HEAT plugin icon: Select the hot plugin in the HEAT library and configure the external boundary conditions; (9) Selection and setting of radiator model: Select radiator model in HEAT library, set radiator parameters, conduct radiator performance test, obtain heat transfer performance parameters, water resistance parameters, and air resistance parameters of radiator, obtain pressure drop curves of coolant passing through radiator at different flow rates and air passing through radiator at different flow rates according to the heat performance parameters, water resistance parameters and air resistance parameters, input the two pressure drop curves as internal flow parameters and external flow parameters into the model, and obtain the heat transfer coefficient by inputting test data; (10) Selection and setting of fan model for electronically controlled silicone oil clutch: Select fan model in HEAT library, give fan diameter and thickness according to fan shape parameters, obtain fan aerodynamic performance curve. Fan aerodynamic performance parameters include static pressure flow curve and efficiency flow curve. Input the two into the model to complete the setting of fan model. Then use signal and control library to model electronically controlled silicone oil clutch. Modeling of electronically controlled silicone oil clutch includes temperature and speed sensors, as well as function expressions to express control logic. (11) Setting vehicle and environmental parameters: Select models related to vehicle parameter settings from the cooling system library, including duty cycle sub-model, engine speed and power calculation model and driving condition definition model; (12) Reflecting the effect of different vehicle speeds on the heat dissipation performance of the radiator: In front of the HEAT plug-in, a function expression is used to represent the effect of different vehicle speeds on the intake pressure in front of the radiator. The function expression is determined by whole vehicle test or three-dimensional CFD simulation. (13) Complete the modeling of the engine thermal management system.

2. The modeling method for an engine thermal management system according to claim 1, characterized in that: In step (2), the coolant flow path is divided into a large circulation and a small circulation according to the connection of the engine cooling system. The connection sequence between the components of the large circulation and the small circulation is determined according to the layout of the cooling system.

3. The modeling method for an engine thermal management system according to claim 1, characterized in that: In step (3), the HEAT library is used to participate in the modeling of the thermal management system.

4. The modeling method for an engine thermal management system according to claim 1, characterized in that: In step (4), the heat exchange between the engine and the cooling system is initially estimated using empirical formulas: in: —Heat exchange between the engine and the cooling system; —The percentage of fuel thermal energy transferred to the cooling system; — Fuel consumption rate of internal combustion engines; —Low calorific value of fuel.

5. The modeling method for an engine thermal management system according to claim 1, characterized in that: The thermal plug-in used in step (8) to manage external flow interactions between thermal components is HEAT11.

6. The modeling method for an engine thermal management system according to claim 1, characterized in that: Step (9) Use the heat transfer parameter preprocessing program built into the modeling software to calculate the semi-empirical heat transfer coefficient.

7. The modeling method for an engine thermal management system according to claim 1, characterized in that: In step (9), if the version of the mechatronics modeling software is low, the heat transfer coefficient is calculated using a semi-empirical formula: in, —The thermal conductivity of the radiator pipes; , —These are the mass flow rates of coolant and air, respectively; , —Air-side convection correction factor; , — Water-side convection correction factor.

8. The modeling method for an engine thermal management system according to claim 1, characterized in that: In step (10), aerodynamic performance parameters are obtained through experiments, or the aerodynamic performance curve of the fan is obtained through CFD three-dimensional simulation.

9. The modeling method for an engine thermal management system according to claim 8, characterized in that: In step (10), the formula for calculating the aerodynamic performance of the fan is: in: —Power consumed by the fan; —Fan torque; in: —Static pressure efficiency; —Fan flow rate; — Fan static pressure.

10. A modeling method for an engine thermal management system according to any one of claims 1-9, characterized in that: The function expression in step (11) is: in: —Intake pressure in front of the radiator at a certain vehicle speed; —Intake pressure in front of the radiator when the vehicle is stationary; —Speed; —Characteristic coefficient of the front of the vehicle.

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