Simulation modeling method of vehicle air conditioning system and air conditioning system simulation model

Abstract

The invention relates to the technical field of vehicle air conditioning system function testing, in particular to a simulation modeling method of a whole vehicle air conditioning system and an air conditioning system simulation model. The method comprises the following steps that based on structural parameters of the heat exchanger, the temperature of two heat exchange bodies after heat exchange in the heat exchanger serves as output parameters of a heat exchanger calculation module, the heat exchanger calculation module is established, and input parameters are determined; according to the source of the input parameters, the flow direction of the output parameters and the control parameters, input parameters and output parameters required for establishing an expansion valve calculation module, a high-low pressure pipeline calculation module and a compressor calculation module are determined; an expansion valve calculation module, a high-low pressure pipeline calculation module and a compressor calculation module are established; all the modules are connected in series to form an operation closed loop, and an air conditioning system simulation model is established. The problems that in the prior art, due to the fact that two-phase heat circulation exists in a whole vehicle air conditioning system, parameters are numerous and complex, and formula modeling is difficult to design and form an operation closed loop can be solved.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle air-conditioning system function testing, and in particular to a simulation modeling method for a vehicle air-conditioning system and an air-conditioning system simulation model. Background Art

[0002] Thermal management systems have become a key technology for new energy vehicles. Unlike traditional vehicles, automotive thermal management is not limited to controlling the temperature of the engine (range extender) and passenger compartment, but also includes controlling the temperature of the motor, electronic control system, and battery system. These systems are interconnected, increasing their complexity.

[0003] Therefore, testing requirements for thermal management systems (thermal management control software) have also increased accordingly. Testing must be conducted as early as possible in the development phase, cover as many scenarios as possible, and maintain a closed-loop testing environment. To meet these testing requirements, model-in-the-loop (MIL) and hardware-in-the-loop (HIL) testing have become the primary approaches to address this problem. Models used in HIL and MIL must meet requirements such as fixed-step execution, easy convergence, high real-time performance, transient computation, and integration with Simulink.

[0004] Due to the complexity of thermal management systems, especially the two-phase heat exchange involved in air conditioning systems, building these models is challenging. Currently, CAE and Simcape are the primary approaches. While CAE models offer relatively high accuracy, they lack the ability to perform transient calculations and require a long modeling cycle. Simcape, while simple and easy to use, offers limited accuracy and slows convergence.

[0005] As for formula modeling, the existing formula modeling is only for single-phase thermal cycles, such as battery water cooling and engine water cooling. Since there are two-phase thermal cycles in the vehicle air-conditioning system, the parameters are numerous and complex. Formula modeling based on single-phase thermal cycles is difficult to design to form an operating closed loop. Summary of the Invention

[0006] The present application provides a simulation modeling method and an air-conditioning system simulation model for a whole vehicle, which can solve the problem in the prior art that due to the existence of a two-phase thermal cycle in the whole vehicle air-conditioning system, the parameters are numerous and complex, and it is difficult to design an operating closed loop based on the formula modeling of a single-phase thermal cycle.

[0007] In order to achieve the above purpose, the technical solution adopted by the present invention is: In one aspect, the present invention provides a simulation modeling method for a vehicle air conditioning system, comprising the following steps: Based on the structural parameters of the heat exchanger, the temperature of the two heat exchangers after heat exchange in the heat exchanger is used as the output parameter of the heat exchanger calculation module, and the input parameters of the heat exchanger calculation module are determined; Determine the input parameters and output parameters required for establishing the expansion valve calculation module, the high and low pressure pipeline calculation module, and the compressor calculation module based on the parameter sources of the input parameters of the heat exchanger calculation module in the vehicle thermal management air conditioning system, the parameter flow direction of the output parameters of the heat exchanger calculation module in the vehicle thermal management air conditioning system, and the control parameters; Establish an expansion valve calculation module, a high and low pressure pipeline calculation module and a compressor calculation module according to the input parameters and output parameters required by the expansion valve calculation module, the high and low pressure pipeline calculation module and the compressor calculation module; According to the parameter flow and parameter source of the input parameters and output parameters in the heat exchanger calculation module, expansion valve calculation module, high and low pressure pipeline calculation module and compressor calculation module, the modules are connected in series to form an operating closed loop of flow, pressure and temperature, and an air-conditioning system simulation model is established.

[0008] In this simulation modeling method, since each heat exchanger is modeled in a fundamentally consistent manner, its output parameters all include the post-heat exchange temperatures of the two heat exchangers. Furthermore, their positions within the vehicle's air conditioning system are spaced apart, making it easier to connect data in series with other calculation modules. This approach first determines the output parameters of each heat exchanger. Then, based on the calculation requirements of each heat exchanger's calculation module and the output of the post-heat exchange temperatures of the two heat exchangers, the required input parameters for each heat exchanger calculation module are determined. This allows the input and output parameters of other calculation modules to be determined based on the source of the input parameters and the flow of the output parameters, accelerating the design efficiency of the entire air conditioning system simulation model.

[0009] In some optional solutions, when determining the input parameters and output parameters required to establish the expansion valve calculation module, the high and low pressure pipeline calculation module, and the compressor calculation module: Based on the parameter sources of the input parameters of the heat exchanger calculation module and the parameter flow directions of the output parameters of the heat exchanger calculation module, the input parameters and output parameters required for establishing the expansion valve calculation module, the high and low pressure pipeline calculation module, and the compressor calculation module are preliminarily selected from the inflow and outflow physical properties of the fluids flowing through the expansion valve, the high and low pressure pipelines, and the compressor, as well as the control parameters; When the input parameters and output parameters required to establish the expansion valve calculation module, the high and low pressure pipeline calculation module, and the compressor calculation module are selected and the input parameters and output parameters of the heat exchanger calculation module do not satisfy the requirement of forming a closed loop of flow, pressure, and temperature; Reselect the input parameters and output parameters required to establish the expansion valve calculation module, high and low pressure pipeline calculation module and compressor calculation module, or adjust the input parameters and output parameters of the heat exchanger calculation module until a closed loop of flow, pressure and temperature operation is formed.

[0010] In this solution, after preliminarily selecting the input parameters and output parameters of the remaining calculation modules, the entire air-conditioning system simulation model is tested to see whether it can form a closed loop of flow, pressure and temperature calculations. The final established air-conditioning system simulation model is required to be able to form a closed loop of flow, pressure and temperature calculations, thereby reducing the possibility of invalid calculation module modeling and improving the modeling efficiency of the entire simulation system.

[0011] In some optional solutions, based on the structural parameters of the heat exchanger, the temperatures of the two heat exchangers after heat exchange in the heat exchanger are used as output parameters of the heat exchanger calculation module, the input parameters of the heat exchanger calculation module are determined, and the heat exchanger calculation module is established, including: Based on the structural parameters of the heat exchanger and the e-NTU model, a heat exchanger calculation module is established; Based on the e-NTU model, the temperatures of the two heat exchangers after heat exchange in the heat exchanger are used as output parameters of the heat exchanger calculation module to determine the input parameters of the heat exchanger calculation module.

[0012] In some optional solutions, the heat exchanger calculation module includes a condenser calculation module and an evaporator calculation module; The output parameters of the condenser calculation module include the refrigerant temperature after the condenser heat exchange and the air temperature after the condenser heat exchange, and the input parameters include the refrigerant temperature, pressure and flow before the condenser heat exchange, and the air temperature and flow before the condenser heat exchange; The output parameters of the evaporator calculation module include the refrigerant temperature after the evaporator heat exchange and the air temperature after the evaporator heat exchange, and the input parameters include the refrigerant dryness, temperature, pressure and flow before the evaporator heat exchange, and the air temperature and flow before the evaporator heat exchange.

[0013] In some optional solutions, the input parameters of the compressor calculation module include compressor speed, compressor inlet refrigerant temperature and pressure, and compressor outlet refrigerant pressure; The output parameters of the compressor calculation module include the refrigerant temperature and flow rate at the compressor outlet, and the compressor power.

[0014] In some optional solutions, the input parameters of the high-pressure pipeline calculation module include the refrigerant temperature and flow rate at the high-pressure pipeline inlet and the refrigerant flow rate at the high-pressure pipeline outlet, and the output parameters include the high-pressure refrigerant temperature and pressure; The input parameters of the low-pressure pipeline calculation module include the refrigerant temperature and flow rate at the low-pressure pipeline inlet and the refrigerant flow rate at the low-pressure pipeline outlet, and the output parameters include the low-pressure refrigerant temperature and pressure.

[0015] In some optional schemes, the expansion valve calculation module includes a thermal expansion valve calculation module, and the input parameters of the thermal expansion valve calculation module include valve effective control parameters, evaporator outlet temperature, thermal expansion valve inlet refrigerant temperature and pressure, and thermal expansion valve outlet refrigerant pressure; the output parameters of the thermal expansion valve calculation module include thermal expansion valve outlet refrigerant temperature, dryness and flow.

[0016] In some optional solutions, the heat exchanger calculation module also includes a coaxial tube calculation module and a battery direct cooling plate calculation module. The output parameters of the coaxial tube calculation module include the high-pressure refrigerant temperature after the coaxial tube heat exchange and the low-pressure refrigerant temperature after the coaxial tube heat exchange, and the input parameters include the high-pressure refrigerant temperature, pressure and flow rate before the coaxial tube heat exchange, and the low-pressure refrigerant temperature, pressure and dryness before the coaxial tube heat exchange; The output parameters of the battery direct cooling plate calculation module include the battery temperature and the refrigerant temperature and dryness after heat exchange of the battery direct cooling plate. The input parameters include the refrigerant dryness, temperature, pressure and flow before heat exchange of the battery direct cooling plate, as well as the battery SOC and current.

[0017] In some optional schemes, the expansion valve calculation module also includes an electronic expansion valve calculation module, and the input parameters of the electronic expansion valve calculation module include valve opening parameters, electronic expansion valve inlet refrigerant temperature and pressure, and electronic expansion valve outlet refrigerant pressure; output parameters include electronic expansion valve outlet refrigerant temperature, dryness and flow.

[0018] On the other hand, the present invention also provides an air-conditioning system simulation model, which is established according to any of the above-mentioned simulation modeling methods for the vehicle air-conditioning system.

[0019] Based on the structural parameters of the heat exchanger, the temperature of the two heat exchangers after heat exchange in the heat exchanger is used as the output parameter of the heat exchanger calculation module, and the input parameters of the heat exchanger calculation module are determined. Compared with the prior art, the advantages of the present invention are: this solution first determines the output parameters of each heat exchanger, establishes each heat exchanger calculation module based on the structural parameters of the heat exchanger, and determines the input parameters required by each heat exchanger calculation module according to the calculation requirements of outputting the temperature of the two heat exchangers after heat exchange. Since the functions and modeling methods of each heat exchanger are basically the same, the output parameters are all determined to be the temperature of the two heat exchangers after heat exchange, and the positions in the vehicle air-conditioning system are also set at intervals, which makes it easier to connect other calculation modules in series in terms of data. In this way, the input parameters and output parameters of other calculation modules can be determined according to the source of the input parameters and the flow direction of the output parameters, so as to speed up the design efficiency of the entire air-conditioning system simulation model. Finally, according to the parameter flow and parameter source of the input parameters and output parameters in the heat exchanger calculation module, expansion valve calculation module, high and low pressure pipeline calculation module and compressor calculation module, the modules are connected in series to form an operating closed loop of flow, pressure and temperature, and an air-conditioning system simulation model is established. Since each module in the air-conditioning system simulation model is a mathematical calculation module established through physical relationships, the air-conditioning system simulation model is easier to converge, has high stability and good real-time performance than the CAE model and Simcape modeling. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0021] Figure 1 This is a flow chart of a simulation modeling method for a vehicle air conditioning system according to an embodiment of the present invention; Figure 2 Schematic diagram of a vehicle air conditioning system according to an embodiment of the present invention; Figure 3 1 is a calculation flow chart of a heat exchanger calculation module in an embodiment of the present invention; Figure 4 1 is a calculation flow chart of a heat exchange calculation unit in an embodiment of the present invention; Figure 5 is a calculation flow chart of the compressor calculation module in an embodiment of the present invention; Figure 6 Schematic diagram of data flow of each module in the air conditioning system simulation model according to an embodiment of the present invention; Figure 7 Schematic diagram of signal trends in the HIL test system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0023] Testing requirements for thermal management systems (thermal management control software) have also increased accordingly. Testing must begin as early as possible in the development phase, cover as many scenarios as possible, and maintain a closed-loop testing environment. Models used for HIL and MIL must meet requirements such as fixed-step execution, easy convergence, high real-time performance, transient computation, and Simulink integration.

[0024] Due to the complexity of thermal management systems, especially the two-phase heat exchange involved in air conditioning systems, building these models is challenging. Currently, CAE and Simcape are the primary approaches. While CAE models offer relatively high accuracy, they lack the ability to perform transient calculations and require a long modeling cycle. Simcape, while simple and easy to use, offers limited accuracy and slows convergence.

[0025] The vehicle air-conditioning system has a two-phase thermal cycle with numerous and complex parameters. It is difficult to design a closed-loop operation system based on the formula modeling of a single-phase thermal cycle.

[0026] This application proposes a simulation modeling method for a vehicle air-conditioning system to solve the above problems.

[0027] like Figure 2 As shown, first a brief introduction is given to the vehicle air-conditioning system. The air-conditioning simulation circuit includes an air-conditioning simulation circuit that controls the temperature of the passenger compartment separately, and an air-conditioning simulation circuit that controls the temperature of the battery pack and the passenger compartment at the same time.

[0028] The air conditioning simulation circuit for controlling the temperature of the passenger compartment includes a basic air conditioning circuit, which includes a compressor, condenser, thermal expansion valve and evaporator in sequence, connected by high- and low-pressure pipelines. An electric fan cools the condenser, and a blower cools the evaporator.

[0029] The air-conditioning simulation circuit for controlling the temperature of the battery pack and the passenger compartment at the same time includes a basic air-conditioning circuit and a battery temperature control circuit. The battery temperature control circuit includes a coaxial tube, an electronic expansion valve and a direct cooling plate in sequence. The thermal expansion valve and the evaporator in the coaxial tube are connected in parallel in the basic air-conditioning circuit at both ends, and the basic air-conditioning circuit and the battery temperature control circuit exchange heat through the coaxial tube.

[0030] like Figure 1As shown, this solution provides a simulation modeling method for a vehicle air conditioning system, including the following steps: S1: Based on the structural parameters of the heat exchanger, the temperatures of the two heat exchangers after heat exchange in the heat exchanger are used as output parameters of the heat exchanger calculation module, a heat exchanger calculation module is established, and input parameters of the heat exchanger calculation module are determined.

[0031] like Figure 3 and Figure 4 As shown, in some optional embodiments, the input parameters of the heat exchanger calculation module are determined. S11: Based on the structural parameters of the heat exchanger and the e-NTU model, a heat exchanger calculation module is established.

[0032] The heat transfer process in each heat exchanger includes three stages: single-phase heat exchange, two-phase heat exchange, and single-phase heat exchange. For the condenser, this includes gas cooling (single-phase heat exchange), gas condensation (two-phase heat exchange), and liquid cooling (single-phase heat exchange). For the evaporator, this includes liquid heating (single-phase heat exchange), liquid boiling (two-phase heat exchange), and gas superheating (single-phase heat exchange).

[0033] Taking the condenser as an example, its heat exchange process includes three regions: gas cooling, gas condensation, and liquid cooling. The coefficients for each region range from 0 to 1, and the sum is 1. The gas entering the heat exchanger is superheated gas from the compressor outlet. Therefore, the region coefficient x1, which cools the gas to saturation temperature, is first calculated through iterative calculation. The region coefficient x2, which completely condenses the gas into liquid, is then calculated. Finally, the temperature of the liquid after subcooling is calculated using the remaining coefficient (1-x1-x2). When calculating these three regions, the air outlet temperature of each region is also calculated. The weighted average of the coefficients and temperatures for each region is used to determine the air outlet temperature output by the module, which is the temperature after heat exchange.

[0034] Based on the above theoretical analysis, a heat exchanger calculation module is established to calculate the temperature of the two heat exchange fluids in the condenser, evaporator and heat exchanger, as well as the temperature of the refrigerant in the battery direct cooling plate after heat exchange. The following steps are included: A1: Based on the heat exchange process between the first heat exchange fluid and the second heat exchange body, a primary single-phase heat exchange calculation unit, a two-phase heat exchange calculation unit and a secondary single-phase heat exchange calculation unit are established in sequence, which are respectively used to input the physical properties of the first heat exchange fluid and the physical properties of the second heat exchange body in the corresponding heat exchange area, and output the temperature of the second heat exchange body and the temperature of the first heat exchange fluid after heat exchange in the corresponding heat exchange area.

[0035] The heat exchange area division process between the first heat exchange fluid and the second heat exchange body is as follows: taking the condenser as an example, the gas cooling area coefficient (primary single-phase heat exchange area coefficient) for cooling the gas to the saturation temperature is first calculated through iterative calculation as x1; then the gas condensation area coefficient (two-phase heat exchange area coefficient) for condensing all the gas into liquid is calculated as x2; finally, the temperature of the liquid after supercooling is calculated according to the remaining coefficient, that is, the liquid cooling area coefficient (secondary single-phase heat exchange area coefficient) is (1-x1-x2), and the changes in flow rate and pressure are ignored during the calculation process.

[0036] Similarly, the calculation process for the evaporator is to first calculate the area coefficient for liquid heating (if the liquid entering the evaporator is subcooled), then calculate the boiling heat transfer, and finally calculate the gas superheat.

[0037] In this example, the following steps are used to sequentially establish a single-phase heat exchange calculation unit, a two-phase heat exchange calculation unit, and a secondary single-phase heat exchange calculation unit: A11: Based on the physical properties of the first heat exchange fluid before and after the single-phase heat exchange of the heat exchanger, the physical properties of the second heat exchange body, and the structural parameters of the heat exchanger, a single-phase heat exchange calculation unit is established based on the e-NTU model to determine the temperature of the output first heat exchange fluid after the single-phase heat exchange and the temperature of the second heat exchange body after the single-phase heat exchange.

[0038] In the single-phase heat exchange calculation unit, the input parameters are the physical properties of the first heat exchange fluid before the single-phase heat exchange of the heat exchanger (at the inlet of the heat exchanger) and the physical properties of the second heat exchange body before the single-phase heat exchange (at the inlet of the heat exchanger); the output parameters are the temperature of the first heat exchange fluid after the single-phase heat exchange and the temperature of the second heat exchange body after the single-phase heat exchange. The single-phase heat exchange area coefficient x1 is obtained through iterative calculation.

[0039] A12: Based on the physical parameters of the first heat exchange fluid before and after two-phase heat exchange, the physical parameters of the second heat exchange body, and the structural parameters of the heat exchanger, a two-phase heat exchange calculation unit is established based on the e-NTU model to output the temperature of the first heat exchange fluid after two-phase heat exchange and the temperature of the second heat exchange body after two-phase heat exchange.

[0040] In the two-phase heat exchange calculation unit, the input parameters are the physical properties of the first heat exchange fluid after a single-phase heat exchange and the physical properties of the second heat exchange body before heat exchange (at the heat exchanger inlet); the output parameters are the temperature of the first heat exchange fluid after two-phase heat exchange and the temperature of the second heat exchange body after two-phase heat exchange, and the two-phase heat exchange area coefficient x2 is calculated.

[0041] A13: Based on the physical parameters of the first heat exchange fluid before and after the secondary single-phase heat exchange of the heat exchanger, the physical parameters of the second heat exchange body, and the structural parameters of the heat exchanger, a secondary single-phase heat exchange calculation unit is established based on the e-NTU model to output the temperature of the first heat exchange fluid after the secondary single-phase heat exchange and the temperature of the second heat exchange body after the secondary single-phase heat exchange.

[0042] In this example, the input to the secondary single-phase heat exchange calculation unit is the physical properties of the first heat exchange fluid after two-phase heat exchange and the physical properties of the second heat exchanger before heat exchange (at the heat exchanger inlet). The output is the temperature of the first heat exchange fluid after the secondary single-phase heat exchange and the temperature of the second heat exchanger after the secondary single-phase heat exchange.

[0043] A2: Determine the temperature of the second heat exchanger after heat exchange according to the temperatures of each region of the second heat exchanger after heat exchange output by the primary single-phase heat exchange calculation unit, the two-phase heat exchange calculation unit, and the secondary single-phase heat exchange calculation unit.

[0044] Specifically, according to the post-heat exchange temperatures of each region of the second heat exchanger output by the primary single-phase heat exchange calculation unit, the two-phase heat exchange calculation unit and the secondary single-phase heat exchange calculation unit, a weighted average is performed based on the regional coefficient to obtain the post-heat exchange temperature of the second heat exchanger, that is, the post-heat exchange temperature of the second heat exchanger output by the heat exchanger simulation module.

[0045] In this example, the temperature of the first heat exchange fluid after the secondary single-phase heat exchange is used as the first heat exchange fluid temperature at the heat exchanger outlet, that is, the first heat exchange fluid temperature after heat exchange output by the heat exchanger simulation module.

[0046] In this example, the primary single-phase heat exchange calculation unit, the two-phase heat exchange calculation unit, and the secondary single-phase heat exchange calculation unit are all established based on the e-NTU (effective unit method) model.

[0047] The establishment process is as follows: first, the surface heat transfer coefficient of the first heat exchange fluid and the second heat exchange body is referenced, then the heat transfer coefficient of the heat exchanger is calculated, and finally the heat transfer power is obtained through the effective unit method. The outlet temperature can be obtained based on the heat transfer power and the mass flow rate and constant pressure heat capacity of the heat transfer medium.

[0048] The specific steps include: A21: Determine the surface heat transfer coefficients of the two heat exchange media based on the physical properties of the first heat exchange fluid and the second heat exchange body.

[0049] The surface heat transfer coefficients of the two heat exchange media, that is, the surface heat transfer coefficients of the first heat exchange fluid and the second heat exchange body, are obtained as shown in the following table:

[0050] Based on the physical properties of the two heat exchangers, i.e., the two heat exchange media, in the input parameters of the heat exchanger calculation module, the surface heat transfer coefficients of the first heat exchange fluid and the second heat exchanger can be obtained by the above-mentioned surface heat transfer coefficient determination algorithm.

[0051] A22: Determine the heat transfer power based on the surface heat transfer coefficients of the two heat transfer media and the heat exchanger parameters.

[0052] Specifically, the total heat transfer coefficient U is calculated according to the following formula:

[0053] Where, h 1 and h 2 is the surface heat transfer coefficient of the two heat transfer media, δ is the pipe wall thickness, λ is the thermal conductivity of the pipe, h o is the outer surface area, h i is the inner surface area, η is the heat transfer efficiency.

[0054] The number of heat transfer units (NTU) is calculated using the following formula:

[0055] Among them, C min It is the smaller value of the heat capacity flow rate between the two media, U is the total heat transfer coefficient of the heat exchanger, and A is the heat exchange area.

[0056] For different types of pipelines, the efficiency ε is calculated as follows:

[0057] Where Cr is the ratio of the heat capacity flow rates of the two media.

[0058] Calculate heat transfer power using the effective unit method (e-NTU) :

[0059] in, is the inlet refrigerant temperature, is the inlet air temperature.

[0060] A23: Determine the outlet specific enthalpy of the first heat exchange fluid or the second heat exchange body based on the heat transfer power, the mass flow rate of the first heat exchange fluid or the second heat exchange body, and the inlet specific enthalpy.

[0061] Specifically, according to the formula: , determine the outlet specific enthalpy of the first heat exchange fluid or the second heat exchange body , where Q is the heat transfer power; m is the mass flow rate of the first heat exchange fluid or the second heat exchange body, h in is the inlet specific enthalpy.

[0062] The calculation of battery temperature in the battery direct cooling plate calculation module includes the following steps: first, the current heat exchange power of the battery direct cooling plate is calculated, the battery heat generation power is calculated according to the battery current and SOC, and the battery temperature is obtained by temperature integration based on the current heat exchange power of the battery direct cooling plate and the battery heat generation power.

[0063] A24: According to the outlet specific enthalpy and inlet pressure of the first heat exchange fluid or the second heat exchange body, the outlet temperature of the first heat exchange fluid or the second heat exchange body is obtained by looking up the table.

[0064] The difference between a battery direct cooling plate and an evaporator is that the air heat transfer coefficient is changed to the heat transfer coefficient between the battery core and the direct cooling plate. The difference between a coaxial tube and an evaporator is that the high-pressure pipe is assumed to be superheated gas, and the low-pressure pipe is saturated gas or superheated gas. Therefore, the liquid heating module is not included in the calculation, and the air heat transfer coefficient is changed to the heat transfer coefficient of the high-pressure superheated gas.

[0065] S12: Based on the e-NTU model, the temperatures of the two heat exchangers after heat exchange in the heat exchanger are used as output parameters of the heat exchanger calculation module to determine the input parameters of the heat exchanger calculation module.

[0066] For the air conditioning simulation loop that controls the temperature of the passenger compartment, the heat exchanger calculation module includes a condenser calculation module and an evaporator calculation module.

[0067] C1: The output parameters of the condenser calculation module include the refrigerant temperature after the condenser heat exchange and the air temperature after the condenser heat exchange. The input parameters include the refrigerant temperature, pressure and flow before the condenser heat exchange, as well as the air temperature and flow before the condenser heat exchange.

[0068] C2: The output parameters of the evaporator calculation module include the refrigerant temperature after the evaporator heat exchange and the air temperature after the evaporator heat exchange. The input parameters include the refrigerant dryness, temperature, pressure and flow before the evaporator heat exchange, as well as the air temperature and flow before the evaporator heat exchange.

[0069] For the air conditioning simulation loop that controls the temperature of both the battery pack and the passenger compartment, including the basic air conditioning loop and the battery temperature control loop, the heat exchanger calculation module also includes the coaxial tube calculation module and the battery direct cooling plate calculation module: C3: The output parameters of the coaxial tube calculation module include the high-pressure refrigerant temperature and the low-pressure refrigerant temperature after the coaxial tube heat exchange. The input parameters include the high-pressure refrigerant temperature, pressure, and flow rate before the coaxial tube heat exchange, as well as the low-pressure refrigerant temperature, pressure, and dryness before the coaxial tube heat exchange.

[0070] C4: The output parameters of the battery direct cooling plate calculation module include the battery temperature and the refrigerant temperature and dryness after the battery direct cooling plate heat exchange. The input parameters include the refrigerant dryness, temperature, pressure and flow before the battery direct cooling plate heat exchange, as well as the battery SOC and current.

[0071] Because each heat exchanger is modeled in a fundamentally consistent manner, its output parameters all include the post-heat exchange temperatures of the two heat exchangers, and its placement within the vehicle's air conditioning system is also spaced apart, making it easier to connect other calculation modules in series. This approach first determines the output parameters of each heat exchanger. Then, based on the calculation requirements of establishing each heat exchanger calculation module and outputting the post-heat exchange temperatures of the two heat exchangers, the required input parameters for each heat exchanger calculation module are determined. This allows the input and output parameters of other calculation modules to be determined based on the source of the input parameters and the flow of the output parameters, accelerating the design efficiency of the entire air conditioning system simulation model.

[0072] S2: Based on the parameter sources of the input parameters of the heat exchanger calculation module in the vehicle thermal management air-conditioning system, the parameter flow direction of the output parameters of the heat exchanger calculation module in the vehicle thermal management air-conditioning system, and the control parameters, determine the input parameters and output parameters required to establish the expansion valve calculation module, the high and low pressure pipeline calculation module, and the compressor calculation module.

[0073] In some optional embodiments, determining the input parameters and output parameters required to establish the expansion valve calculation module, the high and low pressure pipeline calculation module, and the compressor calculation module includes: S21: Based on the parameter sources of the input parameters of the heat exchanger calculation module and the parameter flow direction of the output parameters of the heat exchanger calculation module, the input parameters and output parameters required for establishing the expansion valve calculation module, the high and low pressure pipeline calculation module and the compressor calculation module are preliminarily selected from the inflow physical parameters and outflow physical parameters of the fluid flowing through the expansion valve, the high and low pressure pipelines and the compressor, as well as the control parameters.

[0074] In this step, since the input parameters and output parameters of the heat exchanger calculation module have been preliminarily determined, based on the parameter source of the input parameters of the heat exchanger calculation module in the vehicle air-conditioning system and the parameter flow direction of the output parameters of the heat exchanger calculation module in the vehicle air-conditioning system, the input parameters and output parameters required by the remaining calculation modules can be preliminarily selected from the inflow and outflow physical properties of the expansion valve, high and low pressure pipelines and compressor fluids, as well as the control parameters.

[0075] S22: When the input parameters and output parameters required to establish the expansion valve calculation module, the high and low pressure pipeline calculation module, and the compressor calculation module are selected, and the input parameters and output parameters of the heat exchanger calculation module do not satisfy the formation of a closed loop of flow, pressure, and temperature.

[0076] Since the ultimate goal is to enable the established air-conditioning system simulation model to form a closed loop of flow, pressure and temperature calculations, it is necessary to test whether the entire air-conditioning system simulation model can form a closed loop of flow, pressure and temperature calculations after preliminarily selecting the input parameters and output parameters of the remaining calculation modules.

[0077] S23: Reselect the input parameters and output parameters required to establish the expansion valve calculation module, the high and low pressure pipeline calculation module, and the compressor calculation module, or adjust the input parameters and output parameters of the heat exchanger calculation module until a closed loop of flow, pressure, and temperature operation is formed.

[0078] In this example, through the above steps, the input parameters and output parameters required to establish the expansion valve calculation module, high and low pressure pipeline calculation module, and compressor calculation module are determined. The details are as follows: The input parameters of the compressor calculation module include compressor speed, compressor inlet refrigerant temperature and pressure, and compressor outlet refrigerant pressure; the output parameters of the compressor calculation module include compressor outlet refrigerant temperature and flow, and compressor power.

[0079] The input parameters of the high-pressure pipeline calculation module include the refrigerant temperature and flow rate at the high-pressure pipeline inlet, and the refrigerant flow rate at the high-pressure pipeline outlet, and the output parameters include the high-pressure refrigerant temperature and pressure.

[0080] The input parameters of the low-pressure pipeline calculation module include the refrigerant temperature and flow rate at the low-pressure pipeline inlet, and the refrigerant flow rate at the low-pressure pipeline outlet, and the output parameters include the low-pressure refrigerant temperature and pressure.

[0081] The expansion valve calculation module includes the thermal expansion valve calculation module. Its input parameters include the effective valve control parameters, the evaporator outlet temperature, the refrigerant temperature and pressure at the thermal expansion valve inlet, and the refrigerant pressure at the thermal expansion valve outlet. Its output parameters include the refrigerant temperature, dryness, and flow rate at the thermal expansion valve outlet. The evaporator outlet temperature is used to adjust and control the thermal expansion valve opening.

[0082] For the air-conditioning simulation circuit including the basic air-conditioning circuit and the battery temperature control circuit, the expansion valve calculation module also includes an electronic expansion valve calculation module. The input parameters of the electronic expansion valve calculation module include valve opening parameters, electronic expansion valve inlet refrigerant temperature and pressure, and electronic expansion valve outlet refrigerant pressure; the output parameters include electronic expansion valve outlet refrigerant temperature, dryness and flow.

[0083] S3: establishing an expansion valve calculation module, a high and low pressure pipeline calculation module, and a compressor calculation module according to the input parameters and output parameters required by the expansion valve calculation module, the high and low pressure pipeline calculation module, and the compressor calculation module.

[0084] In this example, the input parameters of the compressor calculation module include compressor speed, compressor inlet refrigerant temperature and pressure, and compressor outlet refrigerant pressure; the output parameters of the compressor calculation module include compressor outlet refrigerant temperature and flow, and compressor power.

[0085] like Figure 5 As shown, specifically, the compressor calculation module needs to construct a compressor outlet temperature calculation unit, a compressor flow calculation unit, and a compressor shaft work calculation unit, which output the compressor outlet refrigerant temperature, compressor outlet refrigerant flow, and compressor shaft work respectively. The construction process of each calculation unit is as follows: D1: Based on the physical relationship between the compressor inlet temperature and inlet pressure, the compressor outlet pressure and the compressor speed, a compressor outlet temperature calculation unit is established to output the compressor outlet refrigerant temperature.

[0086] D11: Based on the inlet temperature and inlet pressure of the compressor, look up the table to obtain the inlet specific entropy and inlet specific enthalpy of the refrigerant at the compressor.

[0087] In this example, based on the physical property parameter table of the refrigerant, the inlet specific entropy and inlet specific enthalpy of the refrigerant at the compressor can be obtained by looking up the table according to the inlet temperature and inlet pressure of the compressor.

[0088] D12: Based on the compressor inlet specific entropy and the compressor outlet pressure, the compressor outlet specific enthalpy is calculated according to isentropic compression.

[0089] D13: Based on the compressor speed and the compressor inlet and outlet pressure ratio, look up the table to obtain the isentropic efficiency.

[0090] In this example, the inlet-outlet pressure ratio of the compressor is the ratio of the inlet pressure to the outlet pressure of the compressor.

[0091] D14: Calculate the actual outlet specific enthalpy of the compressor based on the compressor inlet specific enthalpy, the compressor isentropic compression outlet specific enthalpy, and the isentropic efficiency.

[0092] In this example, according to the formula , calculate the actual outlet specific enthalpy of the compressor. Where: η s is the isentropic efficiency; h in is the inlet specific enthalpy; h s is the isentropic compression outlet specific enthalpy of the compressor; h out is the actual outlet specific enthalpy of the compressor.

[0093] D15: Based on the actual outlet specific enthalpy of the compressor and the outlet pressure of the compressor, look up the table to obtain the outlet temperature of the compressor.

[0094] In this example, the compressor outlet temperature can be obtained based on the actual outlet specific enthalpy of the compressor and the outlet pressure of the compressor through a mapping table of pressure, temperature, and specific enthalpy.

[0095] D2: Based on the physical relationship between the compressor inlet pressure, outlet pressure, displacement and compressor speed, a compressor flow calculation unit is established to output the refrigerant flow rate at the compressor outlet.

[0096] Specifically, according to the formula , determine the refrigerant flow rate at the compressor outlet. Where: G is the mass flow rate; n is the rotational speed; V m is the displacement; η v is the volumetric efficiency.

[0097] D3: Based on the physical relationship between the compressor inlet temperature and inlet pressure, the compressor outlet pressure, the mechanical efficiency and the compressor shaft work, a compressor shaft work calculation unit for outputting the compressor shaft work is established.

[0098] Specifically, first, based on the method in step D1, the compressor inlet specific enthalpy is determined according to the compressor inlet temperature and inlet pressure and the compressor outlet pressure. h in , and the actual outlet specific enthalpy of the compressor h out .

[0099] Then according to the formula , determine the compressor shaft power ,in, is the refrigerant flow rate at the compressor outlet, h in is the inlet specific enthalpy of the compressor, h out is the actual outlet specific enthalpy of the compressor.

[0100] The high-pressure pipeline calculation module and the low-pressure pipeline calculation module need to build a pipeline temperature calculation unit and a pipeline pressure calculation unit to output the pipeline temperature and pipeline pressure respectively. The input parameters are: pipeline inlet refrigerant temperature and flow rate, and pipeline outlet refrigerant flow rate. The construction process of each calculation unit is as follows: For the pipeline pressure calculation unit, the pipeline pressure is calculated by integrating the inlet and outlet flow rates, dividing them by the pipeline volume to estimate the refrigerant density of the current pipeline, and then obtaining the corresponding pressure according to the refrigerant state equation based on the density and temperature.

[0101]

[0102] Where: P For pressure;f() is the equation of state; T in is the inlet temperature; m init is the initial quality of the pipeline; V tube is the pipe volume; m out is the export flow; m in is the inlet flow.

[0103] This module mainly uses the state equation to calculate the refrigerant pressure. The Matin-Hou state equation formula is as follows:

[0104] Where, v is the specific volume of vapor; R is the gas constant; T is the gas temperature; T r is the critical temperature; b 、n、 K 、 A n、 B n 、 C n (n=1…5) are all set constants, is a natural constant.

[0105] For the pipeline temperature calculation unit, only the single-phase heat exchange process is followed, and the heat exchange power is estimated according to natural heat exchange to obtain the temperature attenuation of the refrigerant in the pipeline.

[0106] For the expansion valve calculation module, it is necessary to build the expansion valve outlet refrigerant temperature calculation unit, the expansion valve outlet refrigerant flow calculation unit, and the expansion valve outlet refrigerant dryness calculation unit, which output the expansion valve outlet refrigerant temperature, expansion valve outlet refrigerant flow, and expansion valve outlet refrigerant dryness, respectively. The input parameters are: valve opening parameters, the refrigerant temperature and pressure of the thermal expansion valve inlet, and the refrigerant flow rate of the pipeline outlet. The construction process of each calculation unit is as follows: For the expansion valve outlet refrigerant flow calculation unit, the outlet flow is calculated according to the hydraulic formula, and the flow coefficient C D It is derived from the empirical formula and corrected according to the test data.

[0107]

[0108] Where: m is the mass flow rate; C D is the flow coefficient;A is the opening area; ρ is the density; ν is the specific volume; P in is the inlet pressure; P out is the outlet pressure; k is the correction factor.

[0109] For the expansion valve outlet refrigerant dryness calculation unit, the outlet dryness is calculated based on the assumption that the inlet and outlet enthalpy values ​​(according to the temperature and pressure table) are unchanged. The inlet enthalpy value is calculated first, and then the corresponding dryness of the two-phase fluid at the same enthalpy value is calculated based on the outlet pressure.

[0110] For the expansion valve outlet refrigerant temperature calculation unit, the outlet temperature is calculated based on the dryness. If the dryness is greater than 0, the temperature is the saturation temperature. If the dryness is 0, it is the same as the inlet temperature.

[0111] S4: According to the parameter flow and parameter source of the input parameters and output parameters in the heat exchanger calculation module, expansion valve calculation module, high and low pressure pipeline calculation module and compressor calculation module, the modules are connected in series to form an operating closed loop of flow, pressure and temperature, and an air conditioning system simulation model is established.

[0112] like Figure 6 As shown, in this solution, an air conditioning simulation loop that controls the temperature of both the battery pack and the passenger compartment, including a basic air conditioning loop and a battery temperature control loop, is used as an example: each module is connected in series to form a closed loop of flow, pressure, and temperature, and an air conditioning system simulation model is established. The parameter sources of each module's input parameters and the parameter flows of each module's output parameters are as follows: The input parameters of the compressor calculation module include compressor speed, compressor inlet refrigerant temperature and pressure, and compressor outlet refrigerant pressure; the output parameters of the compressor calculation module include compressor outlet refrigerant temperature and flow, and compressor power.

[0113] The source of the compressor speed is the speed control signal output by the controller, the source of the compressor inlet refrigerant temperature is the outlet temperature calculated by the low-pressure pipeline calculation module; the source of the compressor inlet refrigerant pressure is the low-pressure refrigerant pressure calculated by the low-pressure pipeline calculation module; the source of the compressor outlet refrigerant pressure is the high-pressure refrigerant pressure calculated by the high-pressure pipeline calculation module.

[0114] The output parameters of the condenser calculation module include the refrigerant temperature after the condenser heat exchange and the air temperature after the condenser heat exchange. The input parameters include the refrigerant temperature, pressure and flow before the condenser heat exchange, as well as the air temperature and flow before the condenser heat exchange.

[0115] The source of the refrigerant temperature before (inlet) heat exchange of the condenser is the refrigerant temperature at the compressor outlet; the source of the refrigerant pressure before (inlet) heat exchange of the condenser is the high pressure pressure calculated by the high-pressure pipeline; the source of the refrigerant flow before (inlet) heat exchange of the condenser is the outlet refrigerant flow calculated by the compressor calculation module; the source of the air temperature before (inlet) heat exchange of the condenser is the test set value; the source of the air flow before (inlet) heat exchange of the condenser is calculated and determined based on the cooling fan control speed signal output by the controller.

[0116] The input parameters of the thermal expansion valve calculation module include the effective valve control parameters, the evaporator outlet temperature, the refrigerant temperature and pressure at the thermal expansion valve inlet, and the refrigerant pressure at the thermal expansion valve outlet. The output parameters of the thermal expansion valve calculation module include the refrigerant temperature, dryness fraction, and flow rate at the thermal expansion valve outlet. The evaporator outlet temperature is used to adjust the thermal expansion valve opening.

[0117] The source of the valve's effective control parameters is the controller's output stop valve control signal; the source of the evaporator's outlet temperature is the refrigerant temperature after the evaporator's heat exchange calculated by the evaporator calculation module; the source of the expansion valve's inlet refrigerant temperature is the outlet temperature calculated by the low-pressure pipeline calculation module; the source of the thermal expansion valve's inlet refrigerant pressure is the low-pressure pressure calculated by the low-pressure pipeline calculation module; the source of the thermal expansion valve's outlet refrigerant pressure is the high-pressure pressure calculated by the high-pressure pipeline calculation module.

[0118] The output parameters of the evaporator calculation module include the refrigerant temperature after the evaporator heat exchange and the air temperature after the evaporator heat exchange. The input parameters include the refrigerant dryness, temperature, pressure and flow before the evaporator heat exchange, as well as the air temperature and flow before the evaporator heat exchange.

[0119] The source of the refrigerant dryness before the evaporator heat exchange (inlet) is the outlet refrigerant dryness calculated by the thermal expansion valve calculation module; the source of the refrigerant temperature before the evaporator heat exchange (inlet) is the outlet refrigerant temperature calculated by the thermal expansion valve calculation module; the source of the refrigerant pressure before the evaporator heat exchange (inlet) is the high pressure calculated by the high-pressure pipeline calculation module; the source of the refrigerant flow before the evaporator heat exchange (inlet) is the outlet refrigerant flow calculated by the thermal expansion valve calculation module; the source of the air temperature before the evaporator heat exchange (inlet) is the internal and external circulation control signal output by the controller; the source of the air flow before the evaporator heat exchange (inlet) is the air flow calculated based on the blower speed output by the controller.

[0120] The input parameters of the electronic expansion valve calculation module include valve opening parameters, electronic expansion valve inlet refrigerant temperature and pressure, and electronic expansion valve outlet refrigerant pressure; the output parameters include electronic expansion valve outlet refrigerant temperature, dryness and flow.

[0121] The source of the valve opening parameter of the electronic expansion valve calculation module is the valve opening signal controlled by the controller; the source of the refrigerant temperature at the electronic expansion valve inlet is the high-pressure zone outlet temperature calculated by the coaxial tube calculation module; the source of the refrigerant pressure at the electronic expansion valve inlet is the high-pressure pressure calculated by the high-pressure pipeline calculation module; the source of the refrigerant pressure at the electronic expansion valve outlet is the low-pressure pressure calculated by the low-pressure pipeline calculation module.

[0122] The output parameters of the coaxial tube calculation module include the high-pressure refrigerant temperature after the coaxial tube heat exchange and the low-pressure refrigerant temperature after the coaxial tube heat exchange. The input parameters include the high-pressure refrigerant temperature, pressure and flow rate before the coaxial tube heat exchange, as well as the low-pressure refrigerant temperature, pressure and dryness before the coaxial tube heat exchange.

[0123] The source of the high-pressure refrigerant temperature before coaxial tube heat exchange (high-pressure inlet) is the outlet temperature calculated by the high-pressure pipeline calculation module; the source of the high-pressure refrigerant pressure before coaxial tube heat exchange (high-pressure inlet) is the high-pressure pressure calculated by the high-pressure pipeline calculation module; the source of the high-pressure refrigerant flow before coaxial tube heat exchange (high-pressure inlet) is the outlet flow calculated by the electronic expansion valve calculation module; the source of the low-pressure refrigerant temperature after coaxial tube heat exchange (low-pressure inlet) is the outlet refrigerant temperature calculated by the battery direct cooling plate calculation module; the source of the low-pressure refrigerant pressure after coaxial tube heat exchange (low-pressure inlet) is the low-pressure pressure calculated by the low-pressure pipeline calculation module; the source of the low-pressure refrigerant dryness after coaxial tube heat exchange (low-pressure inlet) is the outlet refrigerant dryness calculated by the battery direct cooling plate calculation module.

[0124] The output parameters of the battery direct cooling plate calculation module include the battery temperature and the refrigerant temperature and dryness after heat exchange of the battery direct cooling plate. The input parameters include the refrigerant dryness, temperature, pressure and flow before heat exchange of the battery direct cooling plate, as well as the battery SOC and current.

[0125] The refrigerant dryness before (inlet) the battery direct cooling plate is derived from the outlet refrigerant dryness calculated by the electronic expansion valve calculation module. The refrigerant temperature before (inlet) the battery direct cooling plate is derived from the outlet refrigerant temperature calculated by the electronic expansion valve calculation module. The refrigerant pressure before (inlet) the battery direct cooling plate is derived from the high-pressure pressure calculated by the high-pressure pipeline calculation module. The refrigerant flow before (inlet) the battery direct cooling plate is derived from the outlet refrigerant flow calculated by the electronic expansion valve calculation module. The battery SOC and current are all test settings.

[0126] The input parameters of the high-pressure pipeline calculation module include the refrigerant temperature and flow rate at the high-pressure pipeline inlet, and the refrigerant flow rate at the high-pressure pipeline outlet, and the output parameters include the high-pressure refrigerant temperature and pressure.

[0127] The source of the refrigerant temperature at the high-pressure pipeline inlet is the outlet refrigerant temperature calculated by the compressor calculation module; the source of the refrigerant flow at the high-pressure pipeline inlet is the outlet refrigerant flow calculated by the compressor calculation module; the source of the refrigerant flow at the high-pressure pipeline outlet is the sum of the outlet refrigerant flows calculated by the thermal expansion valve calculation module and the electronic expansion valve calculation module.

[0128] The input parameters of the low-pressure pipeline calculation module include the refrigerant temperature and flow rate at the low-pressure pipeline inlet, and the refrigerant flow rate at the low-pressure pipeline outlet, and the output parameters include the low-pressure refrigerant temperature and pressure.

[0129] The source of the refrigerant temperature at the low-pressure pipeline inlet is the weighted sum of the outlet refrigerant temperatures calculated by the coaxial tube calculation module and the evaporator calculation module; the source of the refrigerant flow at the low-pressure pipeline inlet is the sum of the outlet refrigerant flow calculated by the thermal expansion valve calculation module and the electronic expansion valve calculation module; the source of the refrigerant flow at the low-pressure pipeline outlet is the outlet refrigerant flow calculated by the compressor calculation module.

[0130] If the passenger compartment temperature control includes the air-conditioning simulation circuit of the basic air-conditioning circuit, the air-conditioning simulation circuit includes a compressor calculation module, a condenser calculation module, a thermal expansion valve calculation module and an evaporator calculation module, which are connected through the high and low pressure pipeline calculation modules. The electric fan cools the condenser and the blower cools the evaporator.

[0131] If the air-conditioning simulation circuits for controlling the temperature of the battery pack and passenger compartment, including the basic air-conditioning circuit and the battery temperature control circuit, are tested simultaneously, then the air-conditioning simulation circuit also includes a coaxial tube calculation module, an electronic expansion valve calculation module, and a battery direct cooling plate calculation module.

[0132] like Figure 7 As shown, when the HIL test is performed on the air-conditioning simulation loop including the basic air-conditioning loop and the battery temperature control loop, the output of the air-conditioning simulation loop is the refrigerant temperature after the evaporator heat exchange (outlet) and the air temperature after the evaporator heat exchange (outlet), the refrigerant temperature after the battery direct cooling plate heat exchange (outlet), the low-pressure refrigerant pressure, the high-pressure refrigerant pressure, the compressor power and the battery temperature. The HIL collects the output of the air-conditioning simulation loop, performs simulation calculations through the control software in the HIL cabinet, and outputs the compressor speed, electronic fan speed, blower speed, shut-off valve open / closed and electronic expansion valve opening, and outputs these parameters to the air-conditioning simulation loop.

[0133] The source of each module's input parameters and the flow of its output parameters are shown in the following table:

[0134] In order to verify whether a closed loop of flow, pressure and temperature can be formed between the input parameters and output parameters of the compressor calculation module, condenser calculation module, thermal expansion valve calculation module, evaporator calculation module, electronic expansion valve calculation module, coaxial tube calculation module, battery direct cooling plate calculation module, high-pressure pipeline calculation module and low-pressure pipeline calculation module, the physical quantities of the compressor calculation module, condenser calculation module, thermal expansion valve calculation module, evaporator calculation module, electronic expansion valve calculation module, coaxial tube calculation module, battery direct cooling plate calculation module, high-pressure pipeline calculation module and low-pressure pipeline calculation module can be connected in series, and then iterative solution verification can be performed through Simulink to verify whether the calculation link for implementing the air-conditioning system simulation model forms a closed loop. If the iterative solution through Simulink can simulate the changing trend of the physical system, it is proved that a closed loop is formed.

[0135] In addition, this solution also provides an air-conditioning system simulation model, which is established according to any of the above-mentioned simulation modeling methods for the vehicle air-conditioning system.

[0136] The sources of input parameters and the flow of output parameters of the heat exchanger calculation module, expansion valve calculation module, high and low pressure pipeline calculation module and compressor calculation module in each model of the air-conditioning system simulation model, as well as the specific calculation methods of each of the above calculation modules, can be found in the detailed embodiment of the simulation modeling method of the above-mentioned vehicle air-conditioning system, and will not be repeated here.

[0137] In addition, after establishing the compressor calculation module, condenser calculation module, thermal expansion valve calculation module, evaporator calculation module, electronic expansion valve calculation module, coaxial tube calculation module, battery direct cooling plate calculation module, high-pressure pipeline calculation module and low-pressure pipeline calculation module based on the simulation modeling method of the whole vehicle air-conditioning system, the above calculation modules can be built as a first-level calculation module, and the refrigerant boiling heat transfer coefficient calculation equation, the heat exchanger air side heat transfer coefficient calculation equation, the air physical parameter calculation equation, the refrigerant condensation heat transfer coefficient calculation equation, the natural heat transfer heat transfer coefficient calculation equation, the refrigerant state equation, the refrigerant single-phase heat transfer coefficient calculation equation and the refrigerant physical parameter calculation equation are used as second-level calculation modules. When building the first-level calculation module, the second-level calculation module can be called. When building the air-conditioning system simulation model, the already established first-level calculation module can be called to establish it, which can improve the module reuse rate, reduce the parameter adjustment workload, and meet the rapid modeling needs after the vehicle model is updated.

[0138] In this solution, the output parameters of each heat exchanger are first determined. Then, based on the calculation requirements of establishing each heat exchanger calculation module and outputting the temperatures of the two heat exchangers after heat exchange, the input parameters required by each heat exchanger calculation module are determined. Since the functions of each heat exchanger are relatively similar, the output parameters all include the temperatures of the two heat exchangers after heat exchange, and their positions in the vehicle air-conditioning system are also set at intervals, which makes it easier to connect other calculation modules in series. In this way, the input parameters and output parameters of other calculation modules can be determined based on the source of the input parameters and the flow direction of the output parameters, thereby accelerating the design efficiency of the entire air-conditioning system simulation model.

[0139] In order to make the established air-conditioning system simulation model form a closed loop of flow, pressure and temperature calculations, after preliminarily selecting the input parameters and output parameters of the remaining calculation modules, the entire air-conditioning system simulation model is tested to see whether it can form a closed loop of flow, pressure and temperature calculations. If the closed loop cannot be achieved, the parameters are adjusted to ensure the reliability of the established air-conditioning simulation loop.

[0140] It should be noted that the serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0141] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit the "first", "second" and "third" to different types.

[0142] In the description of the embodiments of this application, the words "exemplary," "for example," or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary," "for example," or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "for example," or "for example" is intended to present the relevant concepts in a concrete manner.

[0143] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.

[0144] In some processes described in the embodiments of the present application, multiple operations or steps are included that appear in a specific order. However, it should be understood that these operations or steps may not be performed in the order in which they appear in the embodiments of the present application or may be performed in parallel. The sequence numbers of the operations are only used to distinguish between different operations, and the sequence numbers themselves do not represent any order of execution. In addition, these processes may include more or fewer operations, and these operations or steps may be performed in sequence or in parallel, and these operations or steps may be combined.

[0145] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, or the part that contributes to the existing technology, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above and includes a number of instructions for enabling a terminal device to execute the methods described in each embodiment of this application.

[0146] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A simulation modeling method for a vehicle air conditioning system, characterized in that: The following steps are involved: Based on the structural parameters of the heat exchanger, the temperature of the two heat exchangers after heat exchange in the heat exchanger is used as the output parameter of the heat exchanger calculation module, and the input parameters of the heat exchanger calculation module are determined; Determine the input parameters and output parameters required for establishing the expansion valve calculation module, the high and low pressure pipeline calculation module, and the compressor calculation module based on the parameter sources of the input parameters of the heat exchanger calculation module in the vehicle thermal management air conditioning system, the parameter flow direction of the output parameters of the heat exchanger calculation module in the vehicle thermal management air conditioning system, and the control parameters; Establish an expansion valve calculation module, a high and low pressure pipeline calculation module and a compressor calculation module according to the input parameters and output parameters required by the expansion valve calculation module, the high and low pressure pipeline calculation module and the compressor calculation module; According to the parameter flow and parameter source of the input parameters and output parameters in the heat exchanger calculation module, expansion valve calculation module, high and low pressure pipeline calculation module and compressor calculation module, the modules are connected in series to form an operating closed loop of flow, pressure and temperature, and an air-conditioning system simulation model is established.

2. The simulation modeling method of the vehicle air conditioning system according to claim 1, characterized in that: When determining the input and output parameters required to establish the expansion valve calculation module, high and low pressure pipeline calculation module, and compressor calculation module: Based on the parameter sources of the input parameters of the heat exchanger calculation module and the parameter flow directions of the output parameters of the heat exchanger calculation module, the input parameters and output parameters required for establishing the expansion valve calculation module, the high and low pressure pipeline calculation module, and the compressor calculation module are preliminarily selected from the inflow and outflow physical properties of the fluids flowing through the expansion valve, the high and low pressure pipelines, and the compressor, as well as the control parameters; When the input parameters and output parameters required to establish the expansion valve calculation module, the high and low pressure pipeline calculation module, and the compressor calculation module are selected and the input parameters and output parameters of the heat exchanger calculation module do not satisfy the requirement of forming a closed loop of flow, pressure, and temperature; Reselect the input parameters and output parameters required to establish the expansion valve calculation module, high and low pressure pipeline calculation module and compressor calculation module, or adjust the input parameters and output parameters of the heat exchanger calculation module until a closed loop of flow, pressure and temperature operation is formed.

3. The simulation modeling method of the vehicle air conditioning system according to claim 1, characterized in that: The heat exchanger calculation module is established based on the structural parameters of the heat exchanger, with the temperature of the two heat exchangers after heat exchange in the heat exchanger as the output parameter of the heat exchanger calculation module, and the input parameters of the heat exchanger calculation module are determined, including: Based on the structural parameters of the heat exchanger and the e-NTU model, a heat exchanger calculation module is established; Based on the e-NTU model, the temperatures of the two heat exchangers after heat exchange in the heat exchanger are used as output parameters of the heat exchanger calculation module to determine the input parameters of the heat exchanger calculation module.

4. The simulation modeling method of the vehicle air conditioning system according to claim 3, characterized in that: The heat exchanger calculation module includes a condenser calculation module and an evaporator calculation module; The output parameters of the condenser calculation module include the refrigerant temperature after the condenser heat exchange and the air temperature after the condenser heat exchange, and the input parameters include the refrigerant temperature, pressure and flow before the condenser heat exchange, and the air temperature and flow before the condenser heat exchange; The output parameters of the evaporator calculation module include the refrigerant temperature after the evaporator heat exchange and the air temperature after the evaporator heat exchange, and the input parameters include the refrigerant dryness, temperature, pressure and flow before the evaporator heat exchange, and the air temperature and flow before the evaporator heat exchange.

5. The simulation modeling method for a vehicle air conditioning system according to claim 4, characterized in that: The input parameters of the compressor calculation module include compressor speed, compressor inlet refrigerant temperature and pressure, and compressor outlet refrigerant pressure; The output parameters of the compressor calculation module include the refrigerant temperature and flow rate at the compressor outlet, and the compressor power.

6. The simulation modeling method for a vehicle air conditioning system according to claim 4, characterized in that: The input parameters of the high-pressure pipeline calculation module include the refrigerant temperature and flow rate at the high-pressure pipeline inlet and the refrigerant flow rate at the high-pressure pipeline outlet, and the output parameters include the high-pressure refrigerant temperature and pressure; The input parameters of the low-pressure pipeline calculation module include the refrigerant temperature and flow rate at the low-pressure pipeline inlet, and the refrigerant flow rate at the low-pressure pipeline outlet, and the output parameters include the low-pressure refrigerant temperature and pressure.

7. The simulation modeling method of the vehicle air conditioning system according to claim 4, characterized in that: The expansion valve calculation module includes a thermal expansion valve calculation module, the input parameters of which include valve effective control parameters, evaporator outlet temperature, thermal expansion valve inlet refrigerant temperature and pressure, and thermal expansion valve outlet refrigerant pressure; the output parameters of the thermal expansion valve calculation module include thermal expansion valve outlet refrigerant temperature, dryness and flow.

8. The simulation modeling method for a vehicle air conditioning system according to any one of claims 4 to 7, characterized in that: The heat exchanger calculation module also includes a coaxial tube calculation module and a battery direct cooling plate calculation module. The output parameters of the coaxial tube calculation module include the high-pressure refrigerant temperature after the coaxial tube heat exchange and the low-pressure refrigerant temperature after the coaxial tube heat exchange, and the input parameters include the high-pressure refrigerant temperature, pressure and flow rate before the coaxial tube heat exchange, and the low-pressure refrigerant temperature, pressure and dryness before the coaxial tube heat exchange; The output parameters of the battery direct cooling plate calculation module include the battery temperature and the refrigerant temperature and dryness after heat exchange of the battery direct cooling plate. The input parameters include the refrigerant dryness, temperature, pressure and flow before heat exchange of the battery direct cooling plate, as well as the battery SOC and current.

9. The simulation modeling method of the vehicle air conditioning system according to claim 8, characterized in that: The expansion valve calculation module also includes an electronic expansion valve calculation module, the input parameters of which include valve opening parameters, electronic expansion valve inlet refrigerant temperature and pressure, and electronic expansion valve outlet refrigerant pressure; the output parameters include electronic expansion valve outlet refrigerant temperature, dryness and flow.

10. An air conditioning system simulation model, characterized in that: A simulation modeling method for a vehicle air-conditioning system according to any one of claims 1 to 9 is established.

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