A defrosting method of a vehicle heat pump system and a vehicle heat pump system

Abstract

The application discloses a defrosting method of a vehicle heat pump system and the vehicle heat pump system. The method comprises the following steps: obtaining a heat exchange influencing parameter; wherein the heat exchange influencing parameter is a parameter that will affect the heat exchange performance of a condenser of the vehicle heat pump system; predicting a target heat exchange coefficient of the condenser of the vehicle heat pump system based on the heat exchange influencing parameter by using a heat exchange coefficient prediction model; wherein the target heat exchange coefficient is used to represent the heat exchange performance of the condenser; and performing defrosting control on the vehicle heat pump system based on the target heat exchange coefficient. In the foregoing manner, the application can accurately determine whether the condenser of the vehicle heat pump system has a frost formation risk, so that defrosting can be performed in time when the condenser of the vehicle heat pump system has a frost formation risk.

Description

Technical Field

[0001] This application relates to the field of electric vehicle air conditioning technology, and in particular to a defrosting method for a vehicle heat pump system and the vehicle heat pump system. Background Technology

[0002] With the improvement of living standards, the number of vehicles owned per capita in my country is constantly increasing. Creating a good thermal environment inside the vehicle and ensuring the comfort of passengers is crucial to improving the user experience. Currently, most vehicles use heat pump systems for both cooling and heating, which are highly efficient and energy-saving with low energy consumption. However, in winter, the condenser (outdoor heat exchanger) of the heat pump system is prone to frost formation due to low outdoor temperatures, affecting its heat exchange performance and thus impacting the overall performance of the heat pump system. Summary of the Invention

[0003] The main technical problem addressed by this application is to provide a defrosting method and a vehicle heat pump system that can accurately determine whether there is a risk of frost formation on the condenser of the vehicle heat pump system, thereby enabling timely defrosting when there is a risk of frost formation on the condenser of the vehicle heat pump system.

[0004] To address the aforementioned technical problems, this application provides a defrosting method for a vehicle heat pump system. The method includes: acquiring heat transfer influence parameters; wherein the heat transfer influence parameters are parameters that affect the heat transfer performance of the condenser in the vehicle heat pump system; using a heat transfer coefficient prediction model based on the heat transfer influence parameters to predict a target heat transfer coefficient for the condenser of the vehicle heat pump system; wherein the target heat transfer coefficient is used to characterize the heat transfer performance of the condenser; and performing defrosting control on the vehicle heat pump system based on the target heat transfer coefficient.

[0005] Among them, the heat exchange impact parameters include at least one of the system parameters of the vehicle heat pump system and the environmental parameters.

[0006] The heat transfer influence parameters include system parameters and environmental parameters. System parameters include heat transfer area, total heat transfer, and compressor output power. Environmental parameters include logarithmic mean temperature difference, ambient temperature change, and ambient humidity change. Based on these heat transfer influence parameters, a heat transfer coefficient prediction model is used to predict the target heat transfer coefficient of the vehicle heat pump system's condenser. This includes: obtaining an initial heat transfer coefficient using at least the heat transfer area, total heat transfer, and logarithmic mean temperature difference; and using the heat transfer coefficient prediction model based on the initial heat transfer coefficient, compressor output power, ambient temperature change, and ambient humidity change to predict the target heat transfer coefficient of the vehicle heat pump system's condenser.

[0007] The system parameters also include the fouling factor; the initial heat transfer coefficient is obtained by using at least the heat exchange area, the total heat exchange, and the logarithmic mean temperature difference, including: obtaining the product between the fouling factor, the heat exchange area, and the logarithmic mean temperature difference; and using the ratio of the total heat exchange to the product as the initial heat transfer coefficient.

[0008] Among them, defrosting control of the vehicle heat pump system based on the target heat transfer coefficient includes: determining the condenser frosting risk using the target heat transfer coefficient; and using a defrosting strategy corresponding to the frosting risk to control the vehicle heat pump system.

[0009] The method of determining the condenser's frosting risk using the target heat transfer coefficient includes: determining that the condenser has no frosting risk in response to the target heat transfer coefficient being greater than or equal to a first threshold; determining that the condenser has a low frosting risk in response to the target heat transfer coefficient being less than the first threshold but greater than or equal to a second threshold, wherein the second threshold is less than the first threshold; determining that the condenser has a medium frosting risk in response to the target heat transfer coefficient being less than the second threshold but greater than or equal to a third threshold, wherein the third threshold is less than the second threshold; and determining that the condenser has a high frosting risk in response to the target heat transfer coefficient being less than the third threshold.

[0010] The condenser's frosting risk is classified as low or medium; a defrosting strategy corresponding to the frosting risk is used to control the vehicle's heat pump system, including controlling the opening of the vehicle's heat pump system's heat storage defrosting circuit.

[0011] The vehicle heat pump system includes a compressor, evaporator, first expansion valve, second expansion valve, condenser, heat accumulator, defrost heat exchanger, motor, heating element, first four-way reversing valve, second four-way reversing valve, third four-way reversing valve, fourth four-way reversing valve, first three-way reversing valve, second three-way reversing valve, first water pump, second water pump, and third water pump. The heat accumulator is located adjacent to the evaporator, and the defrost heat exchanger is located adjacent to the condenser. The first and second ports of the first four-way reversing valve are connected to the inlet and outlet of the compressor, respectively; the third port of the first four-way reversing valve is connected to the outlet of the condenser; and the fourth port of the first four-way reversing valve is connected to the first port of the first three-way reversing valve. The second port of the first three-way reversing valve is connected to the inlet of the evaporator, and the third port of the first three-way reversing valve is connected to the inlet of the heat accumulator. The first port of the second three-way reversing valve is connected to the outlet of the evaporator, and the second port of the second three-way reversing valve is connected to the outlet of the heat accumulator. The third port of the second three-way reversing valve is connected to one end of the first expansion valve and one end of the second expansion valve. The other ends of the first and second expansion valves are both connected to the inlet of the condenser. The first port of the second four-way reversing valve is connected to the heating element, the second port of the second four-way reversing valve is connected to one end of the first water pump, and the third port of the second four-way reversing valve is connected to the heat accumulator. The fourth port of the valve is connected to one end of the second water pump; the other end of the first water pump is connected to the heating element; the first port of the third four-way reversing valve is connected to the heat accumulator, the second port of the third four-way reversing valve is connected to the defrost heat exchanger, the third port of the third four-way reversing valve is connected to the other end of the second water pump, and the fourth port of the third four-way reversing valve is connected to the first port of the fourth four-way reversing valve; the second water pump is connected in parallel with the heat accumulator; the second port of the fourth four-way reversing valve is connected to the defrost heat exchanger, the third port of the fourth four-way reversing valve is connected to the motor, the fourth port of the fourth four-way reversing valve is connected to one end of the third water pump, and the other end of the third water pump is connected to the motor; the condenser has a low frosting risk. Frost risk; controlling the opening of the heat storage defrosting circuit of the vehicle heat pump system, including: acquiring the motor temperature of the motor; in response to the motor temperature being less than or equal to a first temperature threshold, controlling the second four-way reversing valve and the fourth four-way reversing valve to close, and controlling the third port of the third four-way reversing valve, the second water pump, the third port of the first three-way reversing valve, and the second port of the second three-way reversing valve to open; in response to the motor temperature being greater than or equal to a second temperature threshold, controlling the second four-way reversing valve to close, and controlling the third four-way reversing valve, the fourth four-way reversing valve, the second water pump, the third water pump, the third port of the first three-way reversing valve, and the second port of the second three-way reversing valve to open; wherein, the second temperature threshold is greater than the first temperature threshold.

[0012] The vehicle heat pump system includes a compressor, evaporator, first expansion valve, second expansion valve, condenser, heat accumulator, defrost heat exchanger, motor, heating element, first four-way reversing valve, second four-way reversing valve, third four-way reversing valve, fourth four-way reversing valve, first three-way reversing valve, second three-way reversing valve, first water pump, second water pump, and third water pump; the heat accumulator is located adjacent to the evaporator, and the defrost heat exchanger is located adjacent to the condenser; the first and second ports of the first four-way reversing valve are connected to the inlet and outlet of the compressor, respectively, the third port of the first four-way reversing valve is connected to the outlet of the condenser, and the fourth port of the first four-way reversing valve is connected to the first port of the first three-way reversing valve; the... The second port of the first three-way reversing valve is connected to the inlet of the evaporator; the third port of the first three-way reversing valve is connected to the inlet of the heat accumulator; the first port of the second three-way reversing valve is connected to the outlet of the evaporator; the second port of the second three-way reversing valve is connected to the outlet of the heat accumulator; the third port of the second three-way reversing valve is connected to one end of the first expansion valve and one end of the second expansion valve; the other ends of the first and second expansion valves are both connected to the inlet of the condenser; the first port of the second four-way reversing valve is connected to the heating element; the second port of the second four-way reversing valve is connected to one end of the first water pump; the third port of the second four-way reversing valve is connected to the heat accumulator; the third port of the second four-way reversing valve... The four-port valve is connected to one end of the second water pump; the other end of the first water pump is connected to the heating element; the first port of the third four-way reversing valve is connected to the heat accumulator, the second port of the third four-way reversing valve is connected to the defrost heat exchanger, the third port of the third four-way reversing valve is connected to the other end of the second water pump, and the fourth port of the third four-way reversing valve is connected to the first port of the fourth four-way reversing valve; the second water pump is connected in parallel with the heat accumulator; the second port of the fourth four-way reversing valve is connected to the defrost heat exchanger, the third port of the fourth four-way reversing valve is connected to the motor, the fourth port of the fourth four-way reversing valve is connected to one end of the third water pump, and the other end of the third water pump is connected to the motor; the condenser has a medium frosting risk; control The method for opening the heat storage defrosting circuit of the vehicle heat pump system includes: acquiring the motor temperature; in response to the motor temperature being less than or equal to a third temperature threshold, controlling the fourth four-way reversing valve to close, and controlling the second four-way reversing valve, the third four-way reversing valve, the first water pump, the second water pump, the third port of the first three-way reversing valve, and the second port of the second three-way reversing valve to open; in response to the motor temperature being greater than or equal to a fourth temperature threshold, controlling the second four-way reversing valve, the third four-way reversing valve, the fourth four-way reversing valve, the first water pump, the second water pump, the third water pump, the third port of the first three-way reversing valve, and the second port of the second three-way reversing valve to open; wherein the fourth temperature threshold is greater than the third temperature threshold.

[0013] Among them, the condenser has a high frost risk; using a defrosting strategy corresponding to the frost risk, the vehicle heat pump system is defrosted, including: controlling the heat storage defrosting circuit of the vehicle heat pump system to close, and switching the heating circuit of the vehicle heat pump system to the cooling circuit, so as to perform reverse defrosting on the condenser of the vehicle heat pump system.

[0014] To solve the above-mentioned technical problems, another technical solution adopted in this application is: to provide a vehicle heat pump system, which includes a vehicle heat pump system body and a controller connected to each other, and the controller is used to perform the above-mentioned defrosting method of the vehicle heat pump system.

[0015] The above technical solution utilizes a heat transfer coefficient prediction model based on heat transfer influence parameters to predict the target heat transfer coefficient characterizing the condenser's heat transfer performance. Therefore, determining the target heat transfer coefficient characterizing the condenser's heat transfer performance is efficient and accurate, meaning it can efficiently and accurately determine the heat transfer performance of the condenser in a vehicle heat pump system. Furthermore, defrosting the vehicle heat pump system based on the target heat transfer coefficient can accurately determine whether there is a risk of frost formation on the condenser and enable timely defrosting when such a risk exists, ensuring the condenser's heat transfer capacity in low-temperature, high-humidity winter environments, thereby guaranteeing the vehicle heat pump system's heating capacity in these conditions. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of an embodiment of the defrosting method for a vehicle heat pump system provided in this application;

[0017] Figure 2 yes Figure 1 The flowchart of step S12 shown is a schematic diagram of one embodiment;

[0018] Figure 3 yes Figure 1 The flowchart of step S13 shown is a schematic diagram of one embodiment.

[0019] Figure 4 This is a schematic diagram of an embodiment of the condenser frosting risk provided in this application;

[0020] Figure 5 This is a schematic diagram of one embodiment of the vehicle heat pump system provided in this application. Detailed Implementation

[0021] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0022] In the following description, specific details such as particular system architectures, interfaces, and technologies are presented for illustrative purposes rather than for limiting purposes, in order to provide a thorough understanding of this application.

[0023] In this document, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " generally indicates that the preceding and following related objects have an "or" relationship. Furthermore, "many" in this document means two or more. Moreover, the term "at least one" in this document means any combination of at least two of any one or more of a plurality of objects. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0024] Please see Figure 1 , Figure 1 This is a schematic flowchart of an embodiment of the defrosting method for a vehicle heat pump system provided in this application. It should be noted that if substantially the same result is achieved, this embodiment is not necessarily identical. Figure 1 The illustrated process sequence is limited. For example... Figure 1 As shown, this embodiment includes:

[0025] Step S11: Obtain heat transfer effect parameters.

[0026] When a vehicle heat pump system operates in a low-temperature, high-humidity outdoor environment during winter, the condenser (outdoor heat exchanger) is prone to frost buildup. As the frost layer thickens, the condenser's heat exchange capacity decreases, thus reducing the vehicle's heating capacity. This embodiment describes a method for defrosting the condenser of a vehicle heat pump system to remove frost from its surface, ensuring the condenser's heat exchange capacity under low-temperature, high-humidity conditions during winter, thereby guaranteeing the vehicle's heating capacity in such environments.

[0027] In this embodiment, heat transfer influence parameters are obtained; these parameters are those that affect the heat transfer performance of the condenser in the vehicle's heat pump system. Obtaining these parameters allows for the subsequent determination of the condenser's heat transfer performance based on these parameters, facilitating timely determination of whether defrosting control is needed for the vehicle's heat pump system and enabling timely defrosting of the condenser.

[0028] In one embodiment, the heat transfer influencing parameters include at least one of the system parameters of the vehicle heat pump system and environmental parameters. In a specific embodiment, the heat transfer influencing parameters include both the system parameters of the vehicle heat pump system and environmental parameters. This allows for a more accurate determination of the heat transfer performance of the condenser in the vehicle heat pump system by comprehensively considering both system and environmental parameters. Consequently, it enables a more precise determination of whether to defrost the condenser of the vehicle heat pump system based on its heat transfer performance.

[0029] In one specific embodiment, the system parameters include at least one of the following: compressor output power (i.e., compressor output power), vehicle heat pump system operating time, condenser heat exchange area, and condenser total heat exchange.

[0030] In one specific embodiment, the environmental parameters include at least one of the logarithmic mean temperature difference, the change in ambient temperature, and the change in ambient humidity.

[0031] Step S12: Using the heat transfer coefficient prediction model based on heat transfer influence parameters, predict the target heat transfer coefficient of the condenser of the vehicle heat pump system.

[0032] In this embodiment, a heat transfer coefficient prediction model is used to predict the target heat transfer coefficient of the condenser in the vehicle heat pump system based on heat transfer influence parameters. The target heat transfer coefficient characterizes the heat transfer performance of the condenser in the vehicle heat pump system. Using a pre-trained heat transfer coefficient prediction model based on heat transfer influence parameters to predict the target heat transfer coefficient of the condenser is more efficient and accurate; that is, using the heat transfer coefficient prediction model based on heat transfer influence parameters allows for a more accurate determination of the heat transfer performance of the condenser in the vehicle heat pump system, and consequently, a more accurate determination of the condenser's frosting risk.

[0033] In one embodiment, the heat transfer influencing parameters include system parameters and environmental parameters of the vehicle heat pump system. A heat transfer coefficient prediction model is directly used to predict the target heat transfer coefficient of the condenser in the vehicle heat pump system based on all system and environmental parameters. On one hand, using the heat transfer coefficient prediction model to predict the target heat transfer coefficient of the condenser based on both system and environmental parameters results in a more efficient determination of the condenser's target heat transfer coefficient. On the other hand, the heat transfer coefficient prediction model simultaneously predicts the target heat transfer coefficient of the condenser based on both system and environmental parameters. The predicted target heat transfer coefficient can more accurately characterize the heat transfer performance of the condenser in the vehicle heat pump system, thereby enabling a more accurate determination of whether to defrost the condenser based on its heat transfer performance.

[0034] In other implementations, after determining the initial heat transfer coefficient, a heat transfer coefficient prediction model can be used to predict the target heat transfer coefficient of the condenser of the vehicle heat pump system based on the initial heat transfer coefficient, system parameters, and environmental parameters.

[0035] In one embodiment, the heat transfer coefficient prediction model is pre-trained; specifically, sample heat transfer influence parameters are obtained; the heat transfer coefficient prediction model is trained using the sample heat transfer influence parameters until the heat transfer coefficient prediction model converges.

[0036] Step S13: Based on the target heat transfer coefficient, perform defrosting control on the vehicle heat pump system.

[0037] In this embodiment, defrosting control of the vehicle heat pump system is performed based on a target heat transfer coefficient. The target heat transfer coefficient characterizes the heat transfer performance of the condenser in the vehicle heat pump system; a larger target heat transfer coefficient indicates better heat transfer performance of the condenser and a lower risk of frost formation; a smaller target heat transfer coefficient indicates poorer heat transfer performance and a higher risk of frost formation. Since the target heat transfer coefficient is predicted using a heat transfer coefficient prediction model based on heat transfer influence parameters, determining the target heat transfer coefficient characterizing the condenser's heat transfer performance is efficient and accurate, meaning it can efficiently and accurately determine the heat transfer performance of the condenser in the vehicle heat pump system. Therefore, defrosting the vehicle heat pump system based on the target heat transfer coefficient can accurately determine whether there is a risk of frost formation on the condenser and can perform timely defrosting when there is a risk, ensuring the condenser's heat transfer capacity in low-temperature and high-humidity winter environments, thereby ensuring the vehicle heat pump system's heating capacity in such environments.

[0038] To more effectively defrost condensers under different frost risks, in one embodiment, different defrosting strategies are employed for condensers with different frost risks. Of course, in other embodiments, the same defrosting strategy can be used for condensers with different frost risks, and this is not limited here.

[0039] In the above embodiments, the heat transfer coefficient prediction model is used to predict the target heat transfer coefficient characterizing the condenser's heat transfer performance based on heat transfer influence parameters. Therefore, determining the target heat transfer coefficient characterizing the condenser's heat transfer performance is efficient and accurate, meaning that the heat transfer performance of the vehicle heat pump system's condenser can be determined efficiently and accurately. Furthermore, defrosting the vehicle heat pump system based on the target heat transfer coefficient can accurately determine whether there is a risk of frost formation on the condenser and can perform timely defrosting when there is a risk of frost formation, ensuring the condenser's heat transfer capacity in low-temperature and high-humidity winter environments, thereby guaranteeing the vehicle heat pump system's heating capacity in such environments.

[0040] Please see Figure 2 , Figure 2 yes Figure 1 The flowchart shown in step S12 is a schematic diagram of one embodiment. It should be noted that if there are substantially the same result, this embodiment does not necessarily follow the same pattern. Figure 2 The illustrated process sequence is limited. For example... Figure 2 As shown in the embodiments of this application, the heat transfer influence parameters include system parameters and environmental parameters. The system parameters include heat transfer area, total heat transfer, and compressor output power; the environmental parameters include heat transfer area, total heat transfer, and compressor output power. First, the initial heat transfer coefficient is determined. Then, based on the initial heat transfer coefficient, system parameters, and environmental parameters, a heat transfer coefficient prediction model is used to predict the target heat transfer coefficient of the condenser in the vehicle heat pump system. Specifically, this includes:

[0041] Step S21: Obtain the initial heat transfer coefficient using at least the heat transfer area, total heat transfer, and logarithmic mean temperature difference.

[0042] In this embodiment, the initial heat transfer coefficient is obtained by utilizing at least the heat transfer area, the total heat transfer, and the logarithmic mean temperature difference.

[0043] In one specific implementation, the system parameters also include a fouling factor. In this case, the initial heat transfer coefficient is obtained using at least the heat transfer area, total heat transfer, and logarithmic mean temperature difference. Specifically, the initial heat transfer coefficient is obtained using the heat transfer area, total heat transfer, logarithmic mean temperature difference, and fouling factor. The specific formula for obtaining the initial heat transfer coefficient using the heat transfer area, total heat transfer, logarithmic mean temperature difference, and fouling factor is shown below:

[0044]

[0045] Q=CmΔT2

[0046] Where K1 represents the initial heat transfer coefficient; Q represents the total heat transfer; F represents the heat transfer area; k represents the fouling factor, typically taken as 0.8-0.9; Δt mThis represents the logarithmic mean temperature difference. When ΔT1 (outdoor air temperature change) / ΔT2 (refrigerant temperature change inside the pipe) > 1.7, When ΔT1 (outdoor air temperature change) / ΔT2 (refrigerant temperature change inside the pipe) ≤ 1.7, C represents the specific heat capacity of the refrigerant; m represents the mass of the refrigerant; ΔT2 represents the temperature change of the refrigerant.

[0047] Step S22: Using the heat transfer coefficient prediction model, based on the initial heat transfer coefficient, compressor output power, ambient temperature change, and ambient humidity change, the target heat transfer coefficient of the condenser of the vehicle heat pump system is predicted.

[0048] In this embodiment, a heat transfer coefficient prediction model is used to predict the target heat transfer coefficient of the condenser of the vehicle heat pump system based on the initial heat transfer coefficient, compressor output power, ambient temperature change, and ambient humidity change. In other words, the initial heat transfer coefficient, compressor output power, ambient temperature change, and ambient humidity change are input into the heat transfer coefficient prediction model, which then maps these values ​​to a corresponding output. This mapped output is the target heat transfer coefficient of the condenser of the vehicle heat pump system.

[0049] Please see Figure 3 , Figure 3 yes Figure 1 The flowchart shown in step S13 is a schematic diagram of one embodiment. It should be noted that if there are substantially the same result, this embodiment does not necessarily follow the same pattern. Figure 3 The illustrated process sequence is limited. For example... Figure 3 As shown in the embodiments of this application, different defrosting strategies are adopted for condensers with different frosting risks, specifically including:

[0050] Step S31: Determine the condenser's frost risk using the target heat transfer coefficient.

[0051] In this embodiment, the frost risk of the condenser in the vehicle heat pump system is determined using a target heat transfer coefficient. Determining the frost risk of the condenser allows for subsequent defrosting control of the vehicle heat pump system using a defrosting strategy tailored to that risk, achieving efficient defrosting of the condenser.

[0052] In one embodiment, the frosting risk of the condenser of the vehicle heat pump system is determined by utilizing the relationship between a target heat transfer coefficient and a threshold. Specifically, in response to a target heat transfer coefficient greater than or equal to a first threshold, it is determined that there is no frosting risk in the condenser of the vehicle heat pump system; in response to a target heat transfer coefficient less than the first threshold but greater than or equal to a second threshold, it is determined that the condenser of the vehicle heat pump system has a low frosting risk, wherein the second threshold is less than the first threshold; in response to a target heat transfer coefficient less than the second threshold but greater than or equal to a third threshold, it is determined that the condenser of the vehicle heat pump system has a medium frosting risk, wherein the third threshold is less than the second threshold; and in response to a target heat transfer coefficient less than the third threshold, it is determined that the condenser of the vehicle heat pump system has a high frosting risk.

[0053] The values ​​of the first, second, and third thresholds are not limited and can be set according to actual usage needs.

[0054] For example, such as Figure 4 As shown, Figure 4 This is a schematic diagram of an embodiment of the condenser frosting risk provided in this application. Taking a first threshold of K3, a second threshold of K2, and a third threshold of K1 as examples: when the target heat transfer coefficient k is greater than or equal to K3, it is determined that the condenser of the vehicle heat pump system has no frosting risk; when the target heat transfer coefficient k is less than K3 but greater than or equal to K2, it is determined that the condenser of the vehicle heat pump system has a low frosting risk; when the target heat transfer coefficient k is less than K2 but greater than or equal to K1, it is determined that the condenser of the vehicle heat pump system has a medium frosting risk; and when the target heat transfer coefficient is less than K1, it is determined that the condenser of the vehicle heat pump system has a high frosting risk.

[0055] Step S32: Utilize the defrosting strategy corresponding to the frost risk to control the defrosting of the vehicle's heat pump system.

[0056] In this embodiment, a defrosting strategy corresponding to the frosting risk is used to defrost the vehicle's heat pump system. Different defrosting strategies are employed for condensers under different frosting risks to achieve efficient defrosting of condensers at each frosting risk level.

[0057] Please see Figure 5 , Figure 5This is a schematic diagram of one embodiment of the vehicle heat pump system provided in this application. The vehicle heat pump system includes a compressor 1, an evaporator 2, a first expansion valve 3, a second expansion valve 4, a condenser 5, a heat accumulator 6, a defrost heat exchanger 7, a motor 8, a heating element (PTC) 9, a first four-way reversing valve 10, a second four-way reversing valve 11, a third four-way reversing valve 12, a fourth four-way reversing valve 13, a first three-way reversing valve 14, a second three-way reversing valve 15, a first water pump 16, a second water pump 17, and a third water pump 18. The heat accumulator 6 is arranged adjacent to the evaporator 2, and the defrost heat exchanger 7 is arranged adjacent to the condenser 5. The first and second ports of the first four-way reversing valve 10 are connected to the inlet and outlet of the compressor 1, respectively; the third port of the first four-way reversing valve 10 is connected to the outlet of the condenser 5; and the fourth port of the first four-way reversing valve 10 is connected to the first port of the first three-way reversing valve 14. The second port of the first three-way reversing valve 14 is connected to the inlet of the evaporator 2, and the third port of the first three-way reversing valve 14 is connected to the inlet of the heat accumulator 6. The first port of the second three-way reversing valve 15 is connected to the outlet of the evaporator 2, and the second port of the second three-way reversing valve 15 is connected to the outlet of the heat accumulator 6. The third port of the reversing valve 15 is connected to one end of the first expansion valve 3 and one end of the second expansion valve 4; the other ends of the first expansion valve 3 and the second expansion valve 4 are both connected to the inlet of the condenser 5; the first port of the second four-way reversing valve 11 is connected to the PTC, the second port of the second four-way reversing valve 11 is connected to one end of the first water pump 16, the third port of the second four-way reversing valve 11 is connected to the heat accumulator 6, and the fourth port of the second four-way reversing valve 11 is connected to one end of the second water pump 17; the other end of the first water pump 16 is connected to the PTC; the first port of the third four-way reversing valve 12... The second port of the third four-way reversing valve 12 is connected to the heat accumulator 6, the second port of the third four-way reversing valve 12 is connected to the defrost heat exchanger 7, the third port of the third four-way reversing valve 12 is connected to the other end of the second water pump 17, and the fourth port of the third four-way reversing valve 12 is connected to the first port of the fourth four-way reversing valve 13; the second water pump 17 is connected in parallel with the heat accumulator 6; the second port of the fourth four-way reversing valve 13 is connected to the defrost heat exchanger 7, the third port of the fourth four-way reversing valve 13 is used to connect to the motor, the fourth port of the fourth four-way reversing valve 13 is connected to one end of the third water pump 18, and the other end of the third water pump 18 is used to connect to the motor.

[0058] When the vehicle heat pump system operates in "heating" mode, the heating circuit is open and the heat storage defrost circuit is closed. Specifically, the first expansion valve 3 and compressor 1 in the vehicle heat pump system are open, and the first four-way reversing valve 10 is positioned appropriately to open the heating circuit; the second four-way reversing valve 11, the third four-way reversing valve 12, and the fourth four-way reversing valve 13 are closed, and the third port of the first three-way reversing valve 11 and the second port of the second three-way reversing valve 15 are closed to close the heat storage defrost circuit; at this time, the vehicle heat pump system only includes the condenser 5, compressor 1, evaporator 2, and first expansion valve 3, and the vehicle heat pump system is in "heating" mode. The high-temperature, high-pressure refrigerant from compressor 1 enters the evaporator 2 through the first four-way reversing valve 10, condenses and releases heat, achieving the purpose of heating the air inside the vehicle. At this time, the high-temperature, high-pressure liquid refrigerant enters the condenser 5 after being throttled and depressurized by the first expansion valve 3, and then is drawn into the compressor 1 through the first four-way reversing valve 10, completing one heating cycle. When the vehicle heat pump system operates in "cooling" mode, the cooling circuit of the vehicle heat pump system is open and the heat storage defrost circuit is closed. Specifically, the second expansion valve 4 and compressor 1 in the vehicle heat pump system are open, and the first four-way reversing valve 10 is positioned appropriately to open the cooling circuit; the second four-way reversing valve 11, the third four-way reversing valve 12, and the fourth four-way reversing valve 13 are closed, and the third port of the first three-way reversing valve 11 and the second port of the second three-way reversing valve 15 are closed to close the heat storage defrost circuit; at this time, the vehicle heat pump system only includes the condenser 5, compressor 1, evaporator 2, and second expansion valve 4, and the vehicle heat pump system is in "cooling" mode. The high-temperature, high-pressure refrigerant from compressor 1 enters the condenser 5 through the first four-way reversing valve 10 to condense and release heat. At this time, the high-temperature, high-pressure liquid refrigerant enters the evaporator 2 after being throttled and depressurized by the second expansion valve 4, and then is drawn into the compressor 1 through the first four-way reversing valve 10, completing one cooling cycle.

[0059] In one embodiment, if the condenser of the vehicle heat pump system has a low or medium risk of frosting, a defrosting strategy corresponding to the risk is used to control the defrosting of the vehicle heat pump system. Specifically, this involves controlling the opening of the heat storage defrosting circuit of the vehicle heat pump system. In other words, when the condenser of the vehicle heat pump system has a low or medium risk of frosting, the heat storage defrosting circuit is opened to utilize the heat from the heat storage defrosting circuit to defrost the condenser.

[0060] In one specific embodiment, the condenser of the vehicle heat pump system has a low frost risk. In this case, the heat storage defrosting circuit of the vehicle heat pump system is opened by: acquiring the motor temperature; in response to the motor temperature being less than or equal to a first temperature threshold, controlling the second four-way reversing valve and the fourth four-way reversing valve to close, and controlling the third port of the third four-way reversing valve, the second water pump, the third port of the first three-way reversing valve, and the second port of the second three-way reversing valve to open; in response to the motor temperature being greater than or equal to a second temperature threshold, controlling the second four-way reversing valve to close, and controlling the third four-way reversing valve, the fourth four-way reversing valve, the second water pump, the third water pump, the third port of the first three-way reversing valve, and the second port of the second three-way reversing valve to open; wherein, the second temperature threshold is greater than the first temperature threshold.

[0061] Specifically, such as Figure 5 As shown, when the frost risk of the condenser 5 in the vehicle heat pump system is low and the motor temperature is less than or equal to the first temperature threshold, the second four-way reversing valve 11 and the fourth four-way reversing valve 13 are closed, and the third four-way reversing valve 12, the second water pump 17, the third port of the first three-way reversing valve 14, and the second port of the second three-way reversing valve 15 are opened. With the third port of the first three-way reversing valve 14 and the second port of the second three-way reversing valve 15 open, the high-temperature and high-pressure refrigerant from the compressor 1 will simultaneously pass through the heat accumulator 6, which will absorb the heat of the high-temperature and high-pressure refrigerant to store heat. The second water pump 17 is turned on, which will carry the heat accumulated in the heat accumulator 6 to the defrost heat exchanger 7. Since the defrost heat exchanger 7 is located adjacent to the condenser 5, the heat carried to the defrost heat exchanger 7 will defrost the condenser 5.

[0062] When the condenser 5 of the vehicle heat pump system has a low risk of frosting and the motor temperature is greater than the second temperature threshold, the second four-way reversing valve 11 is closed, and the third port of the third four-way reversing valve 12, the fourth four-way reversing valve 13, the second water pump 17, the third water pump 18, the third port of the first three-way reversing valve 14, and the second port of the second three-way reversing valve 15 are opened. When the third port of the first three-way reversing valve 14 and the second port of the second three-way reversing valve 15 are opened, the high-temperature and high-pressure refrigerant from the compressor 1 will pass through the heat accumulator 6. The heat accumulator 6 will absorb the heat of the high-temperature and high-pressure refrigerant to store heat. The motor will generate heat when it runs. When the second water pump 17 is turned on, it will carry the heat stored in the heat accumulator 6 to the defrost heat exchanger 7. When the third water pump 18 is turned on, it will carry the heat generated by the motor to the defrost heat exchanger 7. Since the defrost heat exchanger 7 is located close to the condenser 5, the heat stored in the heat accumulator 6 and the heat generated by the motor will work together to defrost the condenser 5.

[0063] The size of the first and second temperature thresholds is not limited and can be set according to actual usage needs.

[0064] In one specific embodiment, the condenser of the vehicle heat pump system has a medium frost risk. In this case, the heat storage defrosting circuit of the vehicle heat pump system is opened by controlling the motor temperature to be obtained; in response to the motor temperature being less than or equal to a third temperature threshold, the first water pump and the second water pump are both opened; in response to the motor temperature being greater than or equal to a fourth temperature threshold, the first water pump, the second water pump and the third water pump are all opened; wherein the fourth temperature threshold is greater than the third temperature threshold.

[0065] Specifically, such as Figure 5 As shown, when the frost risk of the condenser 5 of the vehicle heat pump system is medium and the motor temperature is less than or equal to the third temperature threshold, the fourth four-way reversing valve 13 is closed, and the third port of the second four-way reversing valve 11, the third four-way reversing valve 12, the first water pump 16, the second water pump 17, the first three-way reversing valve 14, and the second port of the second three-way reversing valve 15 are opened. When the third port of the first three-way reversing valve 14 and the second port of the second three-way reversing valve 15 are opened, the high-temperature and high-pressure refrigerant from the compressor 1 will pass through the heat accumulator 6, which will absorb the heat of the high-temperature and high-pressure refrigerant to store heat. When the second four-way reversing valve 11 is opened, heat will flow through the PTC, and the PTC will generate heat during operation. When the second water pump 17 is opened, it will carry the heat accumulated in the heat accumulator 6 to the defrost heat exchanger 7. When the first water pump 16 is opened, it will carry the heat generated by the PTC to the defrost heat exchanger 7. Since the defrost heat exchanger 7 is located close to the condenser 5, the heat carried to the defrost heat exchanger 7 will defrost the condenser 5.

[0066] When the condenser 5 of the vehicle heat pump system has a medium frost risk and the motor temperature is greater than or equal to the fourth temperature threshold, the second four-way reversing valve 11, the third four-way reversing valve 12, the fourth four-way reversing valve 13, the first water pump 16, the second water pump 17, the third water pump 18, the third port of the first three-way reversing valve 14, and the second port of the second three-way reversing valve 15 are opened. When the third port of the first three-way reversing valve 14 and the second port of the second three-way reversing valve 15 are opened, the high-temperature and high-pressure refrigerant from the compressor 1 will pass through the heat accumulator 6, which will absorb the heat of the high-temperature and high-pressure refrigerant to store heat. When the second four-way reversing valve 11 is opened, heat will flow through the PTC, which will generate heat during operation. The motor will also generate heat during operation. When the second water pump 17 is opened, it will carry the heat accumulated in the heat accumulator 6 to the defrost heat exchanger 7. When the first water pump 16 is opened, it will carry the heat generated by the PTC to the defrost heat exchanger 7. When the third water pump 18 is opened, it will carry the heat generated by the motor to the defrost heat exchanger 7. Since the defrost heat exchanger 7 is located close to the condenser 5, the heat carried to the defrost heat exchanger 7 will defrost the condenser 5.

[0067] The third and fourth temperature thresholds are not limited in size and can be set according to actual usage needs.

[0068] In one embodiment, the condenser of the vehicle heat pump system has a high risk of frosting. In this case, a defrosting strategy corresponding to the frosting risk is used to control the defrosting of the vehicle heat pump system. Specifically, the heat storage defrosting circuit of the vehicle heat pump system is shut down, and the heating circuit of the vehicle heat pump system is switched to the cooling circuit to perform reverse defrosting on the condenser of the vehicle heat pump system. In other words, when there is a high risk of frosting on the condenser of the vehicle heat pump system, using only the heat storage defrosting circuit of the heat pump system to defrost the condenser of the vehicle heat pump system is no longer effective. Therefore, the heat storage defrosting circuit of the vehicle heat pump system is shut down, and the heating circuit of the vehicle heat pump system is switched to the cooling circuit to use the condenser of the vehicle heat pump system as a heat source to defrost itself.

[0069] This application also provides a vehicle heat pump system, comprising a vehicle heat pump system body and a controller connected to each other. The controller is used to execute the aforementioned defrosting method for the vehicle heat pump system. Since the defrosting method for the vehicle heat pump system provided above uses a heat transfer coefficient prediction model based on heat transfer influence parameters to predict a target heat transfer coefficient characterizing the condenser's heat transfer performance, determining the target heat transfer coefficient characterizing the condenser's heat transfer performance is efficient and accurate. That is, it can efficiently and accurately determine the heat transfer performance of the condenser in the vehicle heat pump system body. Furthermore, defrosting the vehicle heat pump system body based on the target heat transfer coefficient can accurately determine whether there is a risk of frost formation on the condenser of the vehicle heat pump system body, and can perform timely defrosting when there is a risk of frost formation on the condenser of the vehicle heat pump system body, ensuring the condenser's heat transfer capacity in low-temperature and high-humidity winter environments, thereby ensuring the heating capacity of the vehicle heat pump system body in low-temperature and high-humidity winter environments.

[0070] Therefore, the vehicle heat pump system provided in this application can accurately determine whether there is a risk of frost formation on the condenser, and ensure the heat exchange capacity of the condenser in the low temperature and high humidity environment in winter, thereby ensuring the heating capacity of the vehicle heat pump system in the low temperature and high humidity environment in winter.

[0071] If the technical solution of this application involves personal information, the product using this technical solution has clearly informed the user of the personal information processing rules and obtained the user's voluntary consent before processing the personal information. If the technical solution of this application involves sensitive personal information, the product using this technical solution has obtained the user's separate consent before processing the sensitive personal information, and also meets the requirement of "express consent". For example, at personal information collection devices such as cameras, clear and prominent signs are set up to inform users that they have entered the scope of personal information collection and that personal information will be collected. If an individual voluntarily enters the collection scope, it is deemed that they have agreed to the collection of their personal information; or on the personal information processing device, with clear signs / information informing users of the personal information processing rules, authorization is obtained from the individual through pop-up information or by asking the individual to upload their personal information; wherein, the personal information processing rules may include information such as the personal information processor, the purpose of personal information processing, the processing method, and the types of personal information processed.

[0072] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A defrosting method for a vehicle heat pump system, characterized in that, The method includes: Obtain heat exchange impact parameters; wherein, the heat exchange impact parameters are parameters that affect the heat exchange performance of the condenser of the vehicle heat pump system; The target heat transfer coefficient of the condenser of the vehicle heat pump system is predicted using a heat transfer coefficient prediction model based on the heat transfer influence parameters; wherein the target heat transfer coefficient is used to characterize the heat transfer performance of the condenser. Based on the target heat transfer coefficient, defrosting control is performed on the vehicle heat pump system; The vehicle heat pump system includes a compressor, an evaporator, a first expansion valve, a second expansion valve, a condenser, a heat accumulator, a defrost heat exchanger, a motor, heating elements, a first four-way reversing valve, a second four-way reversing valve, a third four-way reversing valve, a fourth four-way reversing valve, a first three-way reversing valve, a second three-way reversing valve, a first water pump, a second water pump, and a third water pump. The heat accumulator is located adjacent to the evaporator, and the defrost heat exchanger is located adjacent to the condenser. The first port and the second port of the first four-way reversing valve are respectively connected to the inlet and outlet of the compressor. The third port of the first three-way reversing valve is connected to the outlet of the condenser; the fourth port of the first four-way reversing valve is connected to the first port of the first three-way reversing valve; the second port of the first three-way reversing valve is connected to the inlet of the evaporator; the third port of the first three-way reversing valve is connected to the inlet of the heat accumulator; the first port of the second three-way reversing valve is connected to the outlet of the evaporator; the second port of the second three-way reversing valve is connected to the outlet of the heat accumulator; the third port of the second three-way reversing valve is connected to one end of the first expansion valve and also to one end of the second expansion valve; the first expansion valve... The other end of the expansion valve and the other end of the second expansion valve are both connected to the inlet of the condenser; the first port of the second four-way reversing valve is connected to the heating element, the second port of the second four-way reversing valve is connected to one end of the first water pump, the third port of the second four-way reversing valve is connected to the heat accumulator, and the fourth port of the second four-way reversing valve is connected to one end of the second water pump; the other end of the first water pump is connected to the heating element; the first port of the third four-way reversing valve is connected to the heat accumulator, and the second port of the third four-way reversing valve is connected to the defrost heat exchanger. The third port of the third four-way reversing valve is connected to the other end of the second water pump, and the fourth port of the third four-way reversing valve is connected to the first port of the fourth four-way reversing valve; the second water pump is connected in parallel with the heat accumulator; the second port of the fourth four-way reversing valve is connected to the defrosting heat exchanger, the third port of the fourth four-way reversing valve is connected to the motor, the fourth port of the fourth four-way reversing valve is connected to one end of the third water pump, and the other end of the third water pump is connected to the motor; the defrosting control of the vehicle heat pump system based on the target heat transfer coefficient includes: The condenser's frosting risk is determined using the target heat transfer coefficient. In response to the frosting risk being low, the motor temperature of the motor is obtained; In response to the motor temperature being less than or equal to a first temperature threshold, the second four-way reversing valve and the fourth four-way reversing valve are controlled to close, and the third four-way reversing valve, the second water pump, the third port of the first three-way reversing valve, and the second port of the second three-way reversing valve are controlled to open. In response to the motor temperature being greater than or equal to a second temperature threshold, the second four-way reversing valve is controlled to close, and the third four-way reversing valve, the fourth four-way reversing valve, the second water pump, the third water pump, the third port of the first three-way reversing valve, and the second port of the second three-way reversing valve are controlled to open; wherein, the second temperature threshold is greater than the first temperature threshold.

2. The method according to claim 1, characterized in that, The heat exchange influence parameters include at least one of the system parameters and environmental parameters of the vehicle heat pump system.

3. The method according to claim 2, characterized in that, The heat transfer influence parameters include the system parameters and the environmental parameters. The system parameters include the heat transfer area, total heat transfer, and compressor output power. The environmental parameters include the logarithmic mean temperature difference, ambient temperature change, and ambient humidity change. The step of using a heat transfer coefficient prediction model based on the heat transfer influence parameters to predict the target heat transfer coefficient of the condenser in the vehicle heat pump system includes: The initial heat transfer coefficient is obtained by using at least the heat transfer area, the total heat transfer, and the logarithmic mean temperature difference; The target heat transfer coefficient of the condenser of the vehicle heat pump system is predicted using the heat transfer coefficient prediction model based on the initial heat transfer coefficient, the compressor output power, the change in ambient temperature, and the change in ambient humidity.

4. The method according to claim 3, characterized in that, The system parameters also include a fouling factor; obtaining the initial heat transfer factor by utilizing at least the heat transfer area, the total heat transfer, and the logarithmic mean temperature difference includes: Obtain the product of the fouling coefficient, the heat exchange area, and the logarithmic mean temperature difference; The ratio of the total heat exchange to the product is used as the initial heat transfer coefficient.

5. The method according to claim 1, characterized in that, The process of determining the condenser's frosting risk using the target heat transfer coefficient includes: In response to the target heat transfer coefficient being greater than or equal to a first threshold, it is determined that the condenser has no risk of frosting. In response to the target heat transfer coefficient being less than the first threshold and greater than or equal to the second threshold, it is determined that the condenser has a low risk of frosting; wherein the second threshold is less than the first threshold; In response to the target heat transfer coefficient being less than the second threshold and greater than or equal to the third threshold, it is determined that the condenser has a risk of frosting; wherein the third threshold is less than the second threshold; In response to the target heat transfer coefficient being less than the third threshold, it is determined that the condenser has a high risk of frosting.

6. The method according to claim 1, characterized in that, The vehicle heat pump system includes a compressor, an evaporator, a first expansion valve, a second expansion valve, a condenser, a heat accumulator, a defrost heat exchanger, a motor, heating elements, a first four-way reversing valve, a second four-way reversing valve, a third four-way reversing valve, a fourth four-way reversing valve, a first three-way reversing valve, a second three-way reversing valve, a first water pump, a second water pump, and a third water pump; the heat accumulator is located adjacent to the evaporator, and the defrost heat exchanger is located adjacent to the condenser; the first port and the second port of the first four-way reversing valve are respectively connected to the inlet and outlet of the compressor. The third port of the four-way reversing valve is connected to the outlet of the condenser; the fourth port of the first four-way reversing valve is connected to the first port of the first three-way reversing valve; the second port of the first three-way reversing valve is connected to the inlet of the evaporator; the third port of the first three-way reversing valve is connected to the inlet of the heat accumulator; the first port of the second three-way reversing valve is connected to the outlet of the evaporator; the second port of the second three-way reversing valve is connected to the outlet of the heat accumulator; the third port of the second three-way reversing valve is connected to one end of the first expansion valve and one end of the second expansion valve; the other ends of the first expansion valve and the other ends of the second expansion valve are both connected to the inlet of the condenser; the first port of the second four-way reversing valve is connected to the heating element; the second port of the second four-way reversing valve is connected to one end of the first water pump; the third port of the second four-way reversing valve is connected to the heat accumulator; the fourth port of the second four-way reversing valve is connected to one end of the second water pump; the other end of the first water pump is connected to the heating element; the first port of the third four-way reversing valve is connected to the heat accumulator. The second port of the third four-way reversing valve is connected to the defrost heat exchanger, the third port of the third four-way reversing valve is connected to the other end of the second water pump, and the fourth port of the third four-way reversing valve is connected to the first port of the fourth four-way reversing valve; the second water pump is connected in parallel with the heat accumulator; the second port of the fourth four-way reversing valve is connected to the defrost heat exchanger, the third port of the fourth four-way reversing valve is connected to the motor, the fourth port of the fourth four-way reversing valve is connected to one end of the third water pump, and the other end of the third water pump is connected to the motor; The condenser has a medium risk of frosting; the method further includes: Obtain the motor temperature of the motor; In response to the motor temperature being less than or equal to a third temperature threshold, the fourth four-way reversing valve is controlled to close, and the second four-way reversing valve, the third four-way reversing valve, the first water pump, the second water pump, the third port of the first three-way reversing valve, and the second port of the second three-way reversing valve are controlled to open. In response to the motor temperature being greater than or equal to a fourth temperature threshold, the second four-way reversing valve, the third four-way reversing valve, the fourth four-way reversing valve, the first water pump, the second water pump, the third water pump, the third port of the first three-way reversing valve, and the second port of the second three-way reversing valve are controlled to open; wherein the fourth temperature threshold is greater than the third temperature threshold.

7. The method according to claim 1, characterized in that, The condenser has a high risk of frosting; the method further includes: The heat storage defrosting circuit of the vehicle heat pump system is shut down, and the heating circuit of the vehicle heat pump system is switched to the cooling circuit to perform reverse defrosting on the condenser of the vehicle heat pump system.

8. A vehicle heat pump system, characterized in that, The vehicle heat pump system includes a vehicle heat pump system body and a controller connected to each other, the controller being used to perform the method according to any one of claims 1-7.

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