Secondary loop thermal management control method and vehicle

Abstract

The invention relates to a secondary loop heat management control method and a vehicle. The secondary loop heat management control method and the vehicle are used for meeting different water inlet temperature requirements on the two sides as much as possible when a passenger compartment and a battery both have cooling requirements. The method comprises the steps that when it is recognized that a passenger compartment and a battery have refrigeration requirements at the same time, the target air outlet temperature of a cold air core, the battery cooling request temperature, the actual air outlet temperature of the cold air core and the actual temperature of a battery inlet are obtained; determining a compressor target rotating speed; according to the first temperature difference between the target air outlet temperature of the cold air core and the actual air outlet temperature of the cold air core, the opening change value of a first three-way valve is determined; determining an opening upper limit value of a first three-way valve and a target rotating speed of a first water pump according to a second temperature difference between the battery refrigeration request temperature and the actual water inlet temperature; the rotating speed of the compressor is controlled according to the target rotating speed of the compressor, the rotating speed of the first water pump is controlled according to the target rotating speed, the opening degree of the first three-way valve is adjusted according to the opening degree change value, and the adjusted opening degree is smaller than or equal to the opening degree upper limit value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vehicle thermal management control, in particular to a secondary loop thermal management system control method and vehicle. BACKGROUND

[0002] At present, the refrigerant of the traditional vehicle air conditioner is usually R134a, and the greenhouse effect index of R134a is relatively high, which is not conducive to environmental protection and will be gradually replaced by other refrigerants. Natural carbon hydrogen refrigerant R290 has become the focus of the industry due to its excellent performance, and R290 can not only meet the requirements of various environmental protection regulations, but also has excellent thermal physical properties. However, R290 refrigerant is flammable and explosive, and has safety problems. If a secondary loop system architecture is adopted, the risk factors of R290 refrigerant can be avoided, and the architecture is shown as Figure 1 Although this architecture can significantly reduce the risk of direct leakage of R290, the complex water circulation of the architecture poses new challenges to the system control strategy. Figure 1 The heat transfer path of the secondary loop thermal management system double refrigeration mode of The strategy problem of cold source distribution under the secondary loop architecture: in the architecture of the R290 secondary loop thermal management system, the core contradiction of cold source distribution is the dynamic competition of the battery safety demand and the passenger cabin comfort demand for limited cold quantity. Prioritizing passenger cabin cooling can meet passenger comfort, or prioritizing battery cooling can meet battery thermal safety. How to control the cold source distribution through reasonable strategy has become a bottleneck for the application of the secondary loop.

[0003] Dynamic decoupling control problem under different temperature requirements of double heat sources: in the secondary loop thermal management system, the cold source comes from the low-temperature carrier refrigerant at the outlet of the water-cooled evaporator chiller when double refrigeration is adopted. The power battery pack and the passenger cabin refrigeration demand show significant temperature difference characteristics. The battery thermal management system (BTMS) requires that the inlet water temperature of the battery cooling be stabilized at 20±2℃, and the inlet water temperature of the air conditioning box water-cooled core body be maintained at 5±0.5℃ when the cabin is refrigerated. How to meet the different inlet water temperature requirements of the two sides through reasonable control strategy and system architecture has become one of the biggest difficulties of the control strategy of the secondary loop architecture. SUMMARY

[0004] The present application relates to a secondary loop thermal management control method and vehicle, which is used to realize how to meet the different inlet water temperature requirements of the two sides when the passenger cabin and the battery both have cooling demand.

[0005] The technical scheme of the present application is: The present application provides a secondary circuit thermal management system control method, the secondary circuit thermal management system comprising: a refrigerant circuit, a low-temperature cooling water circuit and a high-temperature cooling water circuit; The refrigerant circuit and the low-temperature cooling water circuit are coupled through a water-cooled evaporator, and the refrigerant circuit and the high-temperature cooling water circuit are coupled through a water-cooled condenser; The low-temperature cooling water circuit comprises: a first three-way valve, a cooling liquid inlet of the first three-way valve and a cooling liquid outlet of the water-cooled evaporator are in communication, a first outlet of the first three-way valve and a first circuit in which a first water pump and a battery are located are in communication, a second outlet of the first three-way valve and a second circuit in which a cold air core body is located are in communication, an outlet of the first circuit is connected to an inlet of the first circuit through a one-way valve, and the outlet of the first circuit and the outlet of the second circuit are also in communication with the cooling liquid inlet of the water-cooled evaporator; The secondary circuit thermal management system control method comprises: When it is identified that the passenger cabin and the battery simultaneously have a cooling demand, the cold air core body target air outlet temperature, the battery cooling request temperature, the cold air core body actual air outlet temperature and the battery inlet actual temperature are obtained; The compressor target rotating speed that meets the sum of the passenger cabin cooling capacity and the battery cooling capacity demand is determined; According to the first temperature difference between the cold air core body target air outlet temperature and the cold air core body actual air outlet temperature, the opening degree change value of the first three-way valve is determined; According to the second temperature difference between the battery cooling request temperature and the actual water inlet temperature, the opening degree upper limit value of the first three-way valve and the target rotating speed of the first water pump are determined; The rotating speed control of the compressor in the refrigerant circuit is performed according to the compressor target rotating speed, the rotating speed control of the first water pump is performed according to the target rotating speed, the opening degree adjustment of the first three-way valve is performed according to the opening degree change value, and the adjusted opening degree is less than or equal to the opening degree upper limit value; wherein the opening degree of the first three-way valve is positively correlated with the cooling water flow rate flowing into the cold air core body.

[0006] Preferably, the step of determining the compressor target rotating speed that meets the sum of the passenger cabin cooling capacity and the battery cooling capacity demand comprises: PID calculation is performed according to the temperature difference between the cold air core body target air outlet temperature and the cold air core body actual air outlet temperature, and the first compressor target rotating speed that meets the cold air core body target air outlet temperature is determined; PID calculation is performed according to the temperature difference between the battery cooling request temperature and the battery inlet actual temperature, and the second compressor target rotating speed that meets the cold air core body target air outlet temperature is determined; The third compressor target rotating speed is obtained by taking the maximum value of the first compressor target rotating speed and the second compressor target rotating speed. The third compressor target speed is added to a compensation speed to obtain a compressor target speed of the sum of the passenger cabin refrigeration capacity and the battery refrigeration capacity demand; Wherein, when the third compressor target speed is equal to the first compressor target speed, the compensation speed is determined according to the temperature difference between the battery cooling request temperature and the battery inlet actual temperature through table lookup; When the third compressor target speed is equal to the second compressor target speed, the compensation speed is determined according to the temperature difference between the cold air core target air outlet temperature and the cold air core actual air outlet temperature through table lookup.

[0007] Preferably, the greater the first temperature difference, the greater the opening change value of the first three-way valve.

[0008] Preferably, the greater the second temperature difference, the smaller the opening upper limit value of the first three-way valve.

[0009] Preferably, the greater the second temperature difference, the greater the target speed of the first water pump.

[0010] Preferably, the opening change value of the first three-way valve is determined through a first preset relationship table recording the first temperature difference and the opening change value of the first three-way valve.

[0011] Preferably, the opening upper limit value of the first three-way valve is determined through a second preset relationship table recording the second temperature difference and the opening upper limit value of the three-way water valve.

[0012] Preferably, the target speed of the first water pump is determined through a third preset relationship table recording the second temperature difference and the target speed of the first water pump.

[0013] The application also provides a vehicle, which is controlled by the secondary circuit thermal management system control method.

[0014] The beneficial effects of the application are: On the basis of prioritizing the cooling capacity of the low-temperature cooling water circuit to meet the passenger cabin refrigeration demand, reasonable cooling capacity is also provided to the battery side, balancing the game between cabin comfort and battery thermal safety.

[0015] By setting the opening upper limit value of the first three-way valve, it can prevent the cooling capacity from being excessively allocated to the passenger cabin, ensuring that the battery always has sufficient cooling capacity, thereby avoiding battery overheating. At the same time, by adjusting the speed of the first water pump to control the water temperature, the system can accurately meet the cooling demand of the battery, improving the thermal safety of the battery and the overall performance of the system.

[0016] After the first water pump is started, the high-temperature cooling water flowing out of the cooling water channel of the battery will be mixed with the low-temperature cooling water flowing out of the first outlet of the first three-way valve after passing through the one-way valve and returning to the first outlet of the first three-way valve, so that the water inlet temperature of the battery is increased; in this way, the lower inlet temperature requirement of the cold air core can be met, and the higher inlet water temperature requirement of the battery can also be met. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a schematic diagram of the secondary circuit thermal management system in the embodiment of the application; Figure 2 It is a schematic diagram of the secondary circuit thermal management system control method in the embodiment of the application; Figure 3 It is an actual temperature control effect diagram measured after the secondary circuit thermal management system control method of the embodiment of the application is adopted. DETAILED DESCRIPTION

[0018] In order to facilitate the understanding of those skilled in the art, the application patent is further described and explained below by means of the drawings. The description is relatively detailed, but it cannot be understood as limiting the scope of the application patent, and obvious modifications and substitutions of the following examples are within the protection scope of the patent.

[0019] With reference to Figure 1 and Figure 2 , the embodiment of the application provides a secondary circuit thermal management system control method, the secondary circuit thermal management system comprising: a refrigerant circuit, a low-temperature cooling water circuit and a high-temperature cooling water circuit; The refrigerant circuit and the low-temperature cooling water circuit are coupled through a water-cooled evaporator, and the refrigerant circuit and the high-temperature cooling water circuit are coupled through a water-cooled condenser; The low-temperature cooling water circuit comprises: a first three-way valve, a cooling liquid inlet of the first three-way valve and a cooling liquid outlet of the water-cooled evaporator are in communication, a first outlet of the first three-way valve and a first circuit in which a battery is located are in communication, a second outlet of the first three-way valve and a second circuit in which a cold air core is located are in communication, an outlet of the first circuit is connected to an inlet of the first circuit through a one-way valve, and the outlet of the first circuit and the outlet of the second circuit are also in communication with the cooling liquid inlet of the water-cooled evaporator; The secondary circuit thermal management system control method comprises: S101, when it is identified that the passenger compartment and the battery simultaneously have a refrigeration demand, acquiring a cold air core target air outlet temperature, a battery cooling request temperature, a cold air core actual air outlet temperature and a battery inlet actual temperature; S102, determining a compressor target rotating speed that meets the sum of the passenger compartment refrigeration amount and the battery refrigeration amount requirement; S103, determine a change value of the opening degree of the first three-way valve according to a first temperature difference between the target outlet air temperature of the cold air core and the actual outlet air temperature of the cold air core; S104, determine an upper limit value of the opening degree of the first three-way valve and a target rotating speed of the first water pump according to a second temperature difference between the battery refrigeration request temperature and the actual water inlet temperature; S105, perform rotating speed control on the compressor in the refrigerant circuit according to the target rotating speed of the compressor, perform rotating speed control on the first water pump according to the target rotating speed, and perform opening degree adjustment on the first three-way valve according to the change value of the opening degree, and the adjusted opening degree is less than or equal to the upper limit value of the opening degree; The opening degree of the first three-way valve is positively correlated with the cooling water flow rate flowing into the cold air core.

[0020] Referring to Figure 1 In the refrigerant circuit, the refrigerant is pressurized and heated by the compressor 11, enters the water-cooled condenser 12 to release heat, is depressurized and cooled by the electronic expansion valve 15, and then enters the water-cooled evaporator 16 to absorb heat. The low-temperature cooling water circuit is coupled with the refrigerant circuit through the water-cooled evaporator 16, and the cooling liquid absorbs the cold energy of the refrigerant in the water-cooled evaporator 16 and is then distributed to the battery and the cooling circuit of the passenger compartment. The high-temperature cooling water circuit is coupled with the refrigerant circuit through the water-cooled condenser 12, and is used to carry away the heat released by the refrigerant.

[0021] The water-cooled evaporator 16 is a heat exchange device between the refrigerant circuit and the low-temperature cooling water circuit. The refrigerant absorbs the heat of the cooling liquid in the water-cooled evaporator, thereby reducing the temperature of the cooling liquid. The water-cooled condenser 12 is a heat exchange device between the refrigerant circuit and the high-temperature cooling water circuit. The refrigerant releases heat in the water-cooled condenser, which is carried away by the high-temperature cooling water, thereby completing the refrigeration cycle.

[0022] Referring to Figure 1 The refrigerant circuit in the embodiment of the present application further comprises an internal heat exchanger 14 arranged between the water-cooled condenser 12 and the electronic expansion valve 16. The internal heat exchanger 14 uses the low-temperature refrigerant gas at the refrigerant outlet of the water-cooled evaporator 16 to strengthen the cooling effect of the high-temperature refrigerant liquid flowing from the water-cooled condenser 12 to the electronic expansion valve 15. For this purpose, a second three-way valve 17 is arranged at the refrigerant outlet of the water-cooled evaporator 16 and the internal refrigerant inlet of the internal heat exchanger 14. The inlet of the third three-way valve 17 is connected to the refrigerant outlet of the water-cooled evaporator 16, the first outlet of the third three-way valve 17 is connected to the internal refrigerant inlet of the internal heat exchanger 14, the second outlet of the third three-way valve 17 and the internal refrigerant outlet of the internal heat exchanger 14 are connected to the inlet of the compressor 11, the external refrigerant inlet of the internal heat exchanger 14 is connected to the refrigerant outlet of the water-cooled condenser 12 through the expansion water tank 13, the external refrigerant outlet of the internal heat exchanger 14 is connected to the refrigerant inlet of the electronic expansion valve 15, and the refrigerant outlet of the electronic expansion valve 15 is connected to the refrigerant inlet of the water-cooled evaporator 16.

[0023] In the low-temperature cooling water circuit, the cooling water flowing out of the cooling water outlet of the water-cooled evaporator 16 flows into the cooling water inlet of the first three-way valve 22, which is responsible for distributing the pumped low-temperature coolant to two different circuits: the first circuit (i.e., the battery cooling circuit) and the second circuit (i.e., the passenger compartment cooling circuit). In the first circuit, the coolant is transported to the battery 24 by the first water pump 24, absorbs the heat generated by the battery 24, and then returns to the first water pump 23 through the check valve 25. In the second circuit, the coolant directly flows to the heating and air conditioning 26 where the cold air core 261 is located, and the cold air core 261 exchanges heat with the hot air from the passenger compartment under the action of the air blower 262, thereby providing cold air for the passenger compartment. Finally, the cooling water flowing out of the two circuits returns to the water-cooled evaporator 16 through the second interface and the eighth interface of the eight-way valve under the action of the second water pump 21, forming a closed loop circulation.

[0024] Referring to Figure 1 In the high-temperature cooling water circuit, the inlet of the third water pump 31 is connected to the cooling water outlet of the water-cooled condenser 12 through the fifth interface and the third interface of the eight-way valve, and is in communication with the inlet of the third three-way valve 32. The first outlet of the third three-way valve 32 is connected to the radiator 331 of the cooling module 33, and the second outlet of the third three-way valve 32 is connected to the motor 34. The radiator 331 of the cooling module 33 is also connected to the motor 34. The high-temperature cooling water obtained by heat exchange at the water-cooled condenser 12 is pumped into the radiator 331 of the cooling module 33, and the heat is dissipated to the environment by the fan 332, and then enters the motor 34. Alternatively, the high-temperature cooling water obtained by heat exchange at the water-cooled condenser 12 is pumped into the motor 34. Finally, the cooling water in the motor 34 returns to the cooling water inlet of the water-cooled condenser 12 through the sixth interface and the fourth interface of the eight-way valve.

[0025] The design of the first three-way valve 22 allows the coolant to be flexibly distributed according to demand, ensuring that the cooling requirements of the battery and the passenger compartment can be met. The setting of the check valve 25 is to realize the battery water mixing function, and cooperate with the operation of the first water pump 23 to realize the purpose of accurate control of the water temperature at the battery inlet. This design improves the flexibility and reliability of the system, and can effectively cope with different working condition requirements.

[0026] The target temperature (requested temperature) of the passenger compartment is determined according to the request in the passenger compartment, the target cooling temperature of the battery 23 is determined according to the signal sent by the battery management system BMS, and the actual outlet air temperature of the cold air core 261 and the actual inlet water temperature of the battery 24 are determined by the actual arrangement of sensors.

[0027] In the embodiment of the present application, the opening degree of the first three-way water valve 22 directly determines the flow rate of coolant flowing into the cold air core 261. The larger the opening degree, the greater the flow rate of coolant flowing into the cold air core 261; the smaller the opening degree, the smaller the flow rate of coolant flowing into the cold air core 261.

[0028] By setting an upper limit on the opening of the first three-way valve 22, excessive cooling energy is prevented from being distributed to the passenger compartment, ensuring sufficient cooling for the battery at all times, thus preventing overheating. Furthermore, by adjusting the speed of the first water pump 23 to control the water temperature, the system can precisely meet the battery cooling requirements, improving battery thermal safety and overall system performance.

[0029] According to the calculated target speed of the compressor, the speed of the compressor 11 is adjusted by the controller to ensure that the refrigerant circuit can provide sufficient cooling capacity. At the same time, according to the calculated target speed of the first water pump, the speed of the first water pump 23 is adjusted to achieve the mixing of high-temperature water and low-temperature water. Finally, according to the calculated opening change value, the opening of the first three-way valve 22 is adjusted by the electric actuator to ensure that the adjusted opening does not exceed the upper limit of the opening. By precisely controlling the operating status of the compressor 11, the first water pump 23 and the first three-way valve 22, the system can dynamically balance the cooling needs of the passenger compartment and the battery. This closed-loop control strategy not only improves the response speed and flexibility of the system, but also optimizes the operating efficiency of the system and reduces energy consumption. At the same time, by limiting the opening of the first three-way valve 23, the safety and reliability of the system are ensured.

[0030] In the embodiment of the present application, step S102 of determining a target compressor speed that satisfies the sum of the passenger compartment cooling capacity and the battery cooling capacity requirements includes: S1021, performing PID calculation based on the temperature difference between the target outlet temperature of the cold air core and the actual outlet temperature of the cold air core, to determine a target speed of the first compressor that meets the target outlet temperature of the cold air core; S1022, performing PID calculation based on the temperature difference between the battery cooling request temperature and the actual temperature at the battery inlet, to determine a target speed of the second compressor that meets the target outlet temperature of the cold air core; S1023: Obtain a third compressor target speed by taking the larger of the first compressor target speed and the second compressor target speed; S1024: Add the third compressor target speed and the compensation speed to obtain a compressor target speed corresponding to the sum of the passenger compartment cooling capacity and the battery cooling capacity requirements; Wherein, when the third compressor target speed is equal to the first compressor target speed, the compensation speed is determined by looking up a table according to the temperature difference between the battery cooling request temperature and the actual battery inlet temperature; When the third compressor target rotating speed is equal to the second compressor target rotating speed, the compensation rotating speed is determined according to the temperature difference between the cold air core target air outlet temperature and the cold air core actual air outlet temperature.

[0031] Specifically, when calculating the first compressor target rotating speed, the cold air core target air outlet temperature (which is converted from the passenger compartment request temperature set by the user) and the cold air core actual air outlet temperature (measured by a sensor) are first obtained. The temperature difference between the two is calculated, that is: ΔT 乘员舱 =T 目标出风 −T 实际出风 Then, according to the temperature difference, the first compressor target rotating speed satisfying the passenger compartment refrigeration demand is calculated by using a PID control algorithm. The formula of the PID control algorithm is: First compressor target rotating speed=K p1 *ΔT 乘员舱 +K i1 *∫ΔT 乘员舱 dt+K d1 *(d(ΔT 乘员舱 ) / dt) Wherein, K p1 , K i1 and K d1 are proportional, integral and differential coefficients respectively, which are determined by pre-adjustment.

[0032] Similarly, when calculating the second compressor target rotating speed, the battery cooling request temperature (the cooling temperature required for safe operation of the battery) and the battery inlet actual temperature (measured by a sensor) are obtained. The temperature difference between the two is calculated, that is: Δ T 电池 = T 电池请求 − T 电池实际入水 Then, the compressor target rotating speed satisfying the battery refrigeration demand is calculated by using a PID control algorithm. The formula of the PID control algorithm is: Second compressor target rotating speed= K p2 *Δ T 电池 + K i2 *∫Δ T 电池 dt + K d2 *( d (Δ T 电池 ) / dt ) wherein, K p2 、 K i2 and K d2 are proportional, integral and derivative coefficients adjusted for battery cooling demand.

[0033] The system compares the first compressor target speed (the speed that meets the passenger cabin cooling demand) and the second compressor target speed (the speed that meets the battery cooling demand), and takes the larger value as the third compressor target speed, that is: third compressor target speed = max(first compressor target speed, second compressor target speed).

[0034] By taking the larger value, it is ensured that the speed of the compressor can meet the cooling demand of the passenger cabin and the battery at the same time. This strategy avoids the problem of insufficient cooling due to insufficient speed, and improves the reliability and efficiency of the system.

[0035] According to the source of the third compressor target speed, the compensation speed is determined, specifically: if the third compressor target speed is equal to the first compressor target speed (i.e. the passenger cabin demand dominates), the compensation speed is determined according to the temperature difference between the battery cooling request temperature and the battery inlet actual temperature by looking up the table; if the third compressor target speed is equal to the second compressor target speed (i.e. the battery demand dominates), the compensation speed is determined according to the temperature difference between the cold air core target outlet temperature and the cold air core actual outlet temperature by looking up the table.

[0036] The table lookup process of the compensation speed is to find the corresponding compensation speed value from the table according to the pre-set temperature difference and compensation speed mapping relationship.

[0037] Through the above steps S1021-S1024, the compressor target speed that meets the cooling demand of the passenger cabin and the battery can be accurately calculated. This control strategy not only improves the response speed and comfort of the system, but also optimizes the operating efficiency and reliability of the system, ensuring that the cooling demand of the passenger cabin and the battery can be balanced under dynamic working conditions.

[0038] In step S103 of the embodiments of the present application, the opening change value of the first three-way valve 22 is determined by recording the first preset relationship table of the first temperature difference and the opening change value of the first three-way valve 22. The first preset relationship table is shown in Table 1, for example: Table 1 As known from Table 1, the larger the first temperature difference is, the larger the opening change value of the first three-way valve 22 is.

[0039] From the opening request control strategy of the first three-way valve 22, it can be known that when the outlet temperature of the cold air core 261 is too high, the opening of the first three-way valve 22 will always be accumulated. If the upper limit of the opening is not set, the opening of the first three-way valve 22 will be accumulated to the limit value 100%, that is, all the cold energy is distributed to the passenger cabin, which will cause the problem that the battery 24 has no cold source, and the battery thermal safety accident is prone to occur. Therefore, the upper limit of the opening of the first three-way valve 22 needs to be limited. The limiting logic in the embodiment of the present application is inputted by the battery inlet water temperature error, and the output is the upper limit value of the opening of the first three-way valve 22. The specific logical relationship is shown in Table 2 below. When the battery inlet water temperature error is larger, the upper limit value of the opening of the first three-way valve 22 is lower. In this way, when the thermal load of the battery 24 is larger, the system can distribute larger refrigerating capacity.

[0040] In step S104 of the embodiment of the present application, the upper limit value of the opening of the first three-way valve 22 is determined by a second preset relationship table recording the second temperature difference and the upper limit value of the opening of the first three-way valve 22. The second preset relationship table is shown in Table 2 below, for example: As can be known from Table 2, the larger the second temperature difference is, the smaller the upper limit value of the opening of the first three-way valve 22 is.

[0041] Since the temperature difference between the passenger cabin refrigeration request temperature and the battery refrigeration request temperature is large, for example, the battery thermal management system BMS requires that the inlet temperature of the battery 24 is stabilized at 20±2℃ when the battery 24 is cooled, and the inlet temperature of the water-cooled core 261 is required to be maintained at 5±0.5℃ when the cabin is refrigerated. The temperature of the cooling water flowing out of the two ports of the first three-way valve 22 can only be one temperature. In order to balance the two temperature requirements at the same time, a circulating loop formed by the first water pump 23 and the one-way valve 25 is used to meet the two requirements in the embodiment of the present application. Specifically, after the first water pump 23 is started, the high-temperature cooling water flowing out of the cooling water channel of the battery 24 will return to the first outlet of the first three-way valve 22 through the one-way valve 25, and then mix with the low-temperature cooling water flowing out of the first outlet of the first three-way valve 22, so that the inlet water temperature of the battery 24 is increased. In this way, the lower inlet temperature requirement of the cold air core 261 can be met, and the higher inlet water temperature requirement of the battery 24 can also be met. In step S104 of the embodiment of the present application, the target rotating speed of the first water pump 23 is determined by a third preset relationship table recording the second temperature difference and the target rotating speed of the first water pump 23. Moreover, the larger the second temperature difference is, the larger the target rotating speed of the first water pump 23 is.

[0042] The above control method of the embodiment of the present application can ensure that the refrigerating capacity of the low-temperature cooling water circuit is preferentially used to meet the refrigeration demand of the passenger cabin, and at the same time, reasonable refrigerating capacity is provided to the battery side, so as to balance the game between the comfort of the cabin and the thermal safety of the battery. Figure 3The control method can accurately control the water inlet temperature of the cold air core 261 and the water inlet temperature of the battery 24, and solves the contradiction between the different temperature characteristics of the power battery pack and the passenger cabin refrigeration demand in the secondary circuit type thermal management system and the single cold source and single temperature characteristics of the indirect thermal management system architecture.

[0043] In the embodiments of the present application, a vehicle is also provided, which is controlled by the secondary circuit thermal management system control method.

[0044] It should be noted that each of the embodiments in the present specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the embodiments can be referred to each other.

[0045] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present application.

[0046] It should also be noted that in this document, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are used for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or component referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, relationship terms such as "first" and "second" are used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations, nor can it be understood as indicating or implying relative importance. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or terminal device including a series of elements does not include those elements, but also includes other elements not explicitly listed, or includes elements inherent to such process, method, article or terminal device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or terminal device including the element.

[0047] The technical solutions provided by the present application are described in detail above, and the principles and implementation manners of the present application are described by applying specific examples. The above examples are only used to help understand the present application, and the content of the description should not be understood as limiting the present application. Meanwhile, for those skilled in the art, according to the present application, different forms of changes can be made in the specific implementation manners and application ranges, which do not need to be exhausted here, and the obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A secondary circuit thermal management system control method, characterized in that: The secondary circuit thermal management system includes: a refrigerant circuit, a low-temperature cooling water circuit and a high-temperature cooling water circuit; The refrigerant circuit and the low-temperature cooling water circuit are coupled via a water-cooled evaporator, and the refrigerant circuit and the high-temperature cooling water circuit are coupled via a water-cooled condenser; The low-temperature cooling water circuit includes: a first three-way valve, a coolant inlet of the first three-way valve is connected to the coolant outlet of the water-cooled evaporator, a first outlet of the first three-way valve is connected to the first circuit where the first water pump and the battery are located, a second outlet of the first three-way valve is connected to the second circuit where the cold air core is located, the outlet of the first circuit is connected to the inlet of the first circuit through a one-way valve, and the outlets of the first circuit and the second circuit are also connected to the coolant inlet of the water-cooled evaporator; The secondary circuit thermal management system control method includes: When it is recognized that both the passenger compartment and the battery have cooling needs, the target outlet temperature of the cooling core, the battery cooling request temperature, the actual outlet temperature of the cooling core, and the actual temperature of the battery inlet are obtained; Determine the target compressor speed that meets the combined cooling requirements of the passenger compartment and the battery; determining a change in the opening of the first three-way valve according to a first temperature difference between a target outlet temperature of the cold air core and an actual outlet temperature of the cold air core; determining an upper limit of the opening of the first three-way valve and a target speed of the first water pump according to a second temperature difference between the battery cooling request temperature and the actual inlet water temperature; The speed of the compressor in the refrigerant circuit is controlled according to the compressor target speed, the speed of the first water pump is controlled according to the target speed, and the opening of the first three-way valve is adjusted according to the opening change value, and the adjusted opening is less than or equal to the opening upper limit value; wherein the opening size of the first three-way valve is positively correlated with the cooling water flow rate flowing into the cold air core.

2. The secondary circuit thermal management system control method according to claim 1, characterized in that: The steps of determining a target compressor speed that satisfies the combined passenger compartment cooling capacity and battery cooling capacity requirements include: Performing PID calculation based on the temperature difference between the target outlet temperature of the cold air core and the actual outlet temperature of the cold air core to determine the target speed of the first compressor that meets the target outlet temperature of the cold air core; Performing a PID calculation based on the temperature difference between the battery cooling request temperature and the actual temperature at the battery inlet to determine a target speed of the second compressor that meets the target outlet temperature of the cold air core; Obtaining a third compressor target speed by taking the larger of the first compressor target speed and the second compressor target speed; Adding the third compressor target speed and the compensation speed to obtain a compressor target speed corresponding to the sum of the passenger compartment cooling capacity and the battery cooling capacity requirements; Wherein, when the third compressor target speed is equal to the first compressor target speed, the compensation speed is determined by looking up a table according to the temperature difference between the battery cooling request temperature and the actual battery inlet temperature; When the target speed of the third compressor is equal to the target speed of the second compressor, the compensation speed is determined by looking up a table according to the temperature difference between the target outlet temperature of the cold air core and the actual outlet temperature of the cold air core.

3. The secondary circuit thermal management system control method according to claim 1, characterized in that: The greater the first temperature difference is, the greater the change in the opening degree of the first three-way valve is.

4. The secondary circuit thermal management system control method according to claim 1, characterized in that: The larger the second temperature difference is, the smaller the upper limit of the opening degree of the first three-way valve is.

5. The secondary circuit thermal management system control method according to claim 1, characterized in that: The greater the second temperature difference, the greater the target rotational speed of the first water pump.

6. The secondary circuit thermal management system control method according to claim 1, characterized in that the opening change value of the first three-way valve is determined by using a first preset relationship table recording the first temperature difference and the opening change value of the first three-way valve.

7. The secondary circuit thermal management system control method according to claim 1, characterized in that the opening upper limit value of the first three-way valve is determined by a second preset relationship table recording the second temperature difference and the opening upper limit value of the three-way water valve.

8. The secondary circuit thermal management system control method according to claim 1, characterized in that: The target speed of the first water pump is determined by using a third preset relationship table recording the second temperature difference and the target speed of the first water pump.

9. A vehicle, characterized in that: The vehicle controls the secondary circuit thermal management system by using the secondary circuit thermal management system control method according to any one of claims 1 to 8.

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