Thermal management system of vehicle and control method thereof

Abstract

The invention relates to a thermal management system of a vehicle and a control method thereof. The control method of the heat management system of the vehicle can comprise the steps that the environment temperature, the in-vehicle temperature, the air conditioner set temperature, the evaporator target temperature and the evaporator actual temperature are obtained; according to the obtained environment temperature, the in-vehicle temperature, the air conditioner set temperature, the evaporator target temperature and the evaporator actual temperature, the in-vehicle cooling state grade is determined; determining the opening degree of an expansion valve of the battery cooler according to the determined in-vehicle cooling state grade; according to the determined opening degree of the expansion valve of the battery cooler, the rotating speed grade of a pump for the battery is determined; determining the rotating speed of the pump for the battery according to the determined rotating speed grade of the pump for the battery; the pump for the battery is controlled to operate to cool the battery according to the rotational speed of the pump for the battery.

Description

Technical Field

[0001] This invention relates to a vehicle thermal management system and its control method, which can rationally allocate the cooling capacity of the vehicle's thermal management system according to the cooling status inside the vehicle and the cooling status of the battery. Background Technology

[0002] Electric vehicles that use batteries as their power source are equipped with a battery cooling circuit for cooling the battery. This circuit includes a battery chiller, which cools the coolant using heat exchange between the coolant and refrigerant, and then uses the cooled coolant to cool the battery. Typically, the battery chiller is connected to the refrigerant lines of the air conditioning system via a refrigerant branch line to receive refrigerant from the air conditioning system. In this case, the battery chiller in the battery cooling circuit is configured in parallel with the evaporator of the air conditioning system. Therefore, when both the air conditioning system and the battery cooling circuit are operating simultaneously, the cooling effect on the vehicle interior and the cooling effect on the battery will affect each other.

[0003] The existing control logic for the battery cooling circuit controls the pump in the circuit solely based on the battery's cooling status. However, this control logic has the following drawbacks. Specifically, when the air conditioning system and the battery cooling circuit are both operating simultaneously, resulting in insufficient cooling capacity of the thermal management system, excessively high pump speeds in the battery cooling circuit can cause the battery cooler to overheat, reducing the overall cooling efficiency of the thermal management system and affecting the cooling effect inside the vehicle.

[0004] Therefore, a control method is needed to rationally allocate the cooling capacity of the vehicle's thermal management system.

[0005] The information contained in the background section of this invention is only intended to enhance the understanding of the general background of the invention and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The various aspects of the present invention are dedicated to solving the aforementioned problems in the prior art, and other technical problems not mentioned herein will be clearly understood by those skilled in the art through the following detailed description of the specification.

[0007] Various aspects of the present invention can provide a thermal management system for a vehicle.

[0008] The thermal management system may include: a sensor unit, an air conditioning unit, a battery cooling circuit, and a controller. The sensor unit may be configured to sense ambient temperature and vehicle interior temperature. The air conditioning unit may include a compressor, condenser, first expansion valve, and evaporator connected via refrigerant lines, and is configured to cool the vehicle interior. The battery cooling circuit may include a battery, a pump, and a battery cooler connected via battery cooling lines, and is configured to cool the battery. The battery cooler is connected to the refrigerant lines via refrigerant connection lines to receive refrigerant from the refrigerant lines and use the refrigerant to cool the battery. The system includes a second expansion valve installed on the refrigerant connection line upstream of the battery cooler. The controller can be configured to: acquire ambient temperature, vehicle interior temperature, air conditioning set temperature, evaporator target temperature, and evaporator actual temperature from a sensor unit and an air conditioning unit, respectively; determine the vehicle interior cooling status level based on the acquired ambient temperature, vehicle interior temperature, air conditioning set temperature, evaporator target temperature, and evaporator actual temperature; determine the opening degree of the second expansion valve based on the determined vehicle interior cooling status level; determine the pump speed level based on the determined opening degree of the second expansion valve; determine the pump speed based on the determined pump speed level; and control the pump operation to cool the battery based on the pump speed.

[0009] In an exemplary embodiment of the present invention, the controller may be configured to: determine a first parameter and a second parameter less than the first parameter based on the acquired ambient temperature and the air conditioning set temperature; determine the vehicle interior cooling status level as a first vehicle interior cooling status level when the difference between the actual evaporator temperature and the target evaporator temperature is greater than the first parameter and the vehicle interior temperature is higher than the permissible vehicle interior temperature; determine the vehicle interior cooling status level as a second vehicle interior cooling status level when the difference between the actual evaporator temperature and the target evaporator temperature is greater than the first parameter and the vehicle interior temperature is lower than or equal to the permissible vehicle interior temperature; determine the vehicle interior cooling status level as a third vehicle interior cooling status level when the difference between the actual evaporator temperature and the target evaporator temperature is greater than the second parameter and less than or equal to the first parameter; and determine the vehicle interior cooling status level as a fourth vehicle interior cooling status level when the difference between the actual evaporator temperature and the target evaporator temperature is less than or equal to the second parameter.

[0010] In an exemplary embodiment of the present invention, the controller may be configured to: obtain a compressor request speed for battery cooling from an air conditioning unit; when the obtained compressor request speed for battery cooling is greater than or equal to a predetermined value, control the opening of the second expansion valve to the maximum opening; when the obtained compressor request speed for battery cooling is less than the predetermined value, determine the opening of the second expansion valve according to the determined in-vehicle cooling status level.

[0011] In an exemplary embodiment of the present invention, the controller may be configured to: close the second expansion valve when the vehicle interior cooling status level is a first vehicle interior cooling status level; control the opening of the second expansion valve to the minimum opening when the vehicle interior cooling status level is a second vehicle interior cooling status level; and control the opening of the second expansion valve according to the overheating of the battery cooler when the vehicle interior cooling status level is a third vehicle interior cooling status level or a fourth vehicle interior cooling status level.

[0012] In an exemplary embodiment of the present invention, the controller may be configured to: determine the pump speed level as a first speed level when the second expansion valve is closed; determine the pump speed level as a second speed level when the opening degree of the second expansion valve is greater than or equal to the minimum opening degree and less than the first opening degree, wherein the first opening degree is greater than the minimum opening degree; determine the pump speed level as a third speed level when the opening degree of the second expansion valve is greater than or equal to the first opening degree and less than the second opening degree, wherein the second opening degree is greater than the first opening degree; determine the pump speed level as a fourth speed level when the opening degree of the second expansion valve is greater than or equal to the second opening degree and less than the third opening degree, wherein the third opening degree is greater than the second opening degree; determine the pump speed level as a fifth speed level when the opening degree of the second expansion valve is greater than or equal to the third opening degree and less than or equal to the fourth opening degree, wherein the fourth opening degree is less than the maximum opening degree; and determine the pump speed level as a sixth speed level when the opening degree of the second expansion valve is greater than or equal to the fourth opening degree and less than or equal to the maximum opening degree, wherein the fourth opening degree is less than the maximum opening degree.

[0013] In an exemplary embodiment of the present invention, the controller may be configured to: obtain the battery temperature from the battery cooling circuit, and determine the required minimum speed of the pump based on the obtained battery temperature; determine the larger of the speed determined according to the pump speed class and the required minimum speed of the pump as the required speed of the pump, and control the operation of the pump based on the determined required speed of the pump.

[0014] On the other hand, the present invention provides a control method for a vehicle's thermal management system. This control method may include: acquiring ambient temperature, vehicle interior temperature, air conditioning set temperature, evaporator target temperature, and evaporator actual temperature; determining a vehicle interior cooling state level based on the acquired ambient temperature, vehicle interior temperature, air conditioning set temperature, evaporator target temperature, and evaporator actual temperature; determining the opening degree of the battery cooler's expansion valve based on the determined vehicle interior cooling state level; determining the speed level of the pump used for the battery based on the determined opening degree of the battery cooler's expansion valve; determining the speed of the pump used for the battery based on the determined speed level of the pump used for the battery; and controlling the operation of the pump used for the battery to cool the battery based on the speed of the pump used for the battery.

[0015] In an exemplary embodiment of the present invention, determining the in-vehicle cooling status level may include: determining a first parameter and a second parameter less than the first parameter based on the acquired ambient temperature and air conditioning setting temperature; determining the in-vehicle cooling status level as a first in-vehicle cooling status level when the difference between the actual evaporator temperature and the target evaporator temperature is greater than the first parameter and the in-vehicle temperature is higher than the allowable in-vehicle temperature; determining the in-vehicle cooling status level as a second in-vehicle cooling status level when the difference between the actual evaporator temperature and the target evaporator temperature is greater than the first parameter and the in-vehicle temperature is lower than or equal to the allowable in-vehicle temperature; determining the in-vehicle cooling status level as a third in-vehicle cooling status level when the difference between the actual evaporator temperature and the target evaporator temperature is greater than the second parameter and less than or equal to the first parameter; and determining the in-vehicle cooling status level as a fourth in-vehicle cooling status level when the difference between the actual evaporator temperature and the target evaporator temperature is less than or equal to the second parameter.

[0016] In an exemplary embodiment of the present invention, determining the opening degree of the expansion valve of the battery cooler may include: obtaining the compressor request speed for battery cooling; when the obtained compressor request speed for battery cooling is greater than or equal to a predetermined value, controlling the opening degree of the expansion valve of the battery cooler to the maximum opening degree; when the obtained compressor request speed for battery cooling is less than the predetermined value, determining the opening degree of the expansion valve of the battery cooler according to the determined in-vehicle cooling status level.

[0017] In an exemplary embodiment of the present invention, determining the opening degree of the expansion valve of the battery cooler may include: closing the expansion valve of the battery cooler when the vehicle interior cooling status level is a first vehicle interior cooling status level; controlling the opening degree of the expansion valve of the battery cooler to the minimum when the vehicle interior cooling status level is a second vehicle interior cooling status level; and controlling the opening degree of the expansion valve of the battery cooler according to the superheat of the battery cooler when the vehicle interior cooling status level is a third vehicle interior cooling status level or a fourth vehicle interior cooling status level.

[0018] In an exemplary embodiment of the present invention, determining the speed level of the pump for the battery may include: determining the speed level of the pump for the battery as a first speed level when the expansion valve of the battery cooler is closed; determining the speed level of the pump for the battery as a second speed level when the opening degree of the expansion valve of the battery cooler is greater than or equal to the minimum opening degree and less than the first opening degree, wherein the first opening degree is greater than the minimum opening degree; determining the speed level of the pump for the battery as a third speed level when the opening degree of the expansion valve of the battery cooler is greater than or equal to the first opening degree and less than the second opening degree, wherein the second opening degree is greater than the first opening degree; when When the opening degree of the expansion valve of the battery cooler is greater than or equal to the second opening degree and less than the third opening degree, the speed level of the pump used for the battery is determined as the fourth speed level, wherein the third opening degree is greater than the second opening degree; when the opening degree of the expansion valve of the battery cooler is greater than or equal to the third opening degree and less than the fourth opening degree, the speed level of the pump used for the battery is determined as the fifth speed level, wherein the fourth opening degree is greater than the third opening degree; when the opening degree of the expansion valve of the battery cooler is greater than or equal to the fourth opening degree and less than or equal to the maximum opening degree, the speed level of the pump used for the battery is determined as the sixth speed level, wherein the fourth opening degree is less than the maximum opening degree.

[0019] In an exemplary embodiment of the present invention, determining the rotational speed of the pump for the battery may include: acquiring the battery temperature; determining a minimum required rotational speed of the pump for the battery based on the acquired battery temperature; determining the larger of the rotational speed determined according to the rotational speed class of the pump for the battery and the minimum required rotational speed of the pump for the battery as the required rotational speed of the pump for the battery; and controlling the operation of the pump for the battery based on the determined required rotational speed of the pump for the battery.

[0020] The systems and methods of the present invention have other features and advantages that will be apparent from or will be set forth in detail in the accompanying drawings and following detailed description, which together serve to explain the particular principles of the invention. Attached Figure Description

[0021] The above and other objects, features, and advantages of the invention will become clearer from the following detailed description presented in conjunction with the accompanying drawings, in which:

[0022] Figure 1 This is a schematic diagram illustrating a vehicle thermal management system according to an exemplary embodiment of the present invention;

[0023] Figure 2 This is a block diagram illustrating the configuration of a vehicle's thermal management system according to an exemplary embodiment of the present invention;

[0024] Figure 3A flowchart illustrating a control method for a vehicle's thermal management system according to an exemplary embodiment of the present invention. Detailed Implementation

[0025] It should be understood that the term “vehicle” or “of a vehicle” or other similar terms used herein generally include motor vehicles, such as passenger cars including sport utility vehicles (SUVs), buses, trucks, passenger cars of various commercial vehicles, boats including various boats and ships, aircraft, etc., and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from non-petroleum energy sources).

[0026] Although the exemplary embodiments are described as utilizing multiple units to perform the exemplary process, it should be understood that the exemplary process can also be performed by one or more modules. Additionally, it will be understood that the term "controller" refers to a hardware device including memory and a processor. The memory is configured to store modules, and the processor is specifically configured to execute said modules to perform one or more processes further described below.

[0027] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It is further understood that when the terms “comprising” and / or “including” are used in this specification, they specifically refer to the presence of the stated features, values, steps, operations, elements, and / or components, but do not exclude the presence or additional presence of one or more other features, values, steps, operations, elements, components, and / or combinations thereof. As used herein, the term “and / or” includes any and / or all combinations of one or more of the associated enumerations.

[0028] The following description, with reference to the accompanying drawings, outlines a vehicle thermal management system and its control method according to an exemplary embodiment of the present invention.

[0029] Figure 1 This is a schematic diagram illustrating a thermal management system for a vehicle according to an exemplary embodiment of the present invention. Figure 2 This is a configuration block diagram illustrating a vehicle thermal management system according to an exemplary embodiment of the present invention.

[0030] like Figure 1 and Figure 2 As shown, the vehicle's thermal management system may include: an air conditioning unit 10, a battery cooling circuit 20, a sensor unit 40, and a controller 50.

[0031] The air conditioning unit 10 may include a compressor 12, a condenser 13, a first expansion valve 14, and an evaporator 15 connected via a refrigerant line 11. The evaporator 15 can cool the air flowing into the vehicle, thereby cooling the vehicle interior.

[0032] The battery cooling circuit 20 may include a battery 22, a pump 23, and a battery cooler 30 connected via a battery cooling line 21. The battery cooler 30 may be connected to a refrigerant line 11 via a refrigerant connection line 31 to receive refrigerant from the refrigerant line 11. A second expansion valve 32 is provided on the refrigerant connection line 31 upstream of the battery cooler.

[0033] The second expansion valve 32 can be an electronically adjustable expansion valve. The second expansion valve 32 expands the refrigerant flowing into the battery cooler 30 through the refrigerant connection line 31. The expanded refrigerant exchanges heat with the coolant flowing through the battery 22 in the battery cooler 30, thus cooling the coolant flowing through the battery. The cooled coolant is circulated back to the battery 22 by the operation of the pump 23, thereby cooling the battery 22.

[0034] Therefore, the battery cooler 30 of the battery cooling circuit 20 is configured in parallel with the evaporator 15 of the air conditioning unit 10. When the air conditioning unit 10 and the battery cooling circuit 20 are cooling simultaneously, the controller 50 can allocate the cooling capacity of the thermal management system according to the cooling status inside the vehicle and the cooling status of the battery.

[0035] The sensor unit 40 may consist of multiple sensors installed in the vehicle. Preferably, the sensor unit 40 may include an ambient temperature sensor 41 for sensing ambient temperature and an interior temperature sensor 42 for sensing interior temperature.

[0036] Controller 50 can be a standalone controller or integrated with a controller located in the vehicle. In one example, controller 50 can be integrated with the controller of the air conditioning system, the vehicle control unit (VCU), and the controller of the battery thermal management system (BMS).

[0037] The controller 50 can communicate with the sensor unit 40, the air conditioning unit 10, and the battery cooling circuit 20, for example, via CAN communication. Thus, the controller 50 can obtain the ambient temperature and the interior temperature from the sensor unit 40, the air conditioning set temperature, the evaporator target temperature, and the actual evaporator temperature from the air conditioning unit 10, and the battery temperature from the battery cooling circuit 20.

[0038] Based on the acquired ambient temperature, vehicle interior temperature, air conditioning set temperature, evaporator target temperature, and actual evaporator temperature, controller 50 can determine the vehicle interior cooling status level. Based on the determined vehicle interior cooling status level, controller 50 can determine the opening degree of the second expansion valve 32. Based on the determined opening degree of the second expansion valve 32, controller 50 can determine the speed level of pump 23. Based on the determined speed level of pump 23, controller 50 can control pump 23 to operate at the corresponding speed, thereby cooling battery 22.

[0039] Specifically, when the air conditioning unit 10 is operating in cooling mode, the controller 50 can obtain the air conditioning set temperature T1 from the air conditioning unit 10 and the ambient temperature T2 from the sensor unit 40. The air conditioning set temperature T1 can be the air conditioning temperature set by the user or the default temperature set by the thermal management system based on the operating mode of the air conditioning unit. Based on the air conditioning set temperature T1 and the ambient temperature T2, the controller 50 can determine a first parameter A and a second parameter a (the units of the first parameter A and the second parameter a are in °C). The first parameter A has a larger value than the second parameter a.

[0040] Furthermore, based on the air conditioning set temperature T1 and the ambient temperature T2, the controller 50 can determine the permissible interior temperature T3. The permissible interior temperature T3 represents the highest acceptable interior temperature based on the current air conditioning set temperature T1 and ambient temperature T2. If the interior temperature exceeds the permissible interior temperature, it may cause discomfort to the occupants.

[0041] Table 1 below shows the first parameter A, the second parameter a, and the permissible interior temperature T3, determined based on the air conditioning set temperature T1 and the ambient temperature T2. The units of the parameters in Table 1 are °C.

[0042] Table 1

[0043]

[0044] The controller 50 can further obtain the evaporator target temperature T4 and the actual evaporator temperature T5 from the air conditioning unit 10, and obtain the vehicle interior temperature T6 from the sensor unit 40. The evaporator target temperature T4 can be calculated based on the cooling load of the air conditioning unit 10 and output to the controller 50. The vehicle interior temperature T6 can represent the current actual temperature inside the vehicle.

[0045] Based on the difference between the actual evaporator temperature T5 and the target evaporator temperature T4, and the difference between the interior temperature T6 and the permissible interior temperature T3, the controller 50 can determine the interior cooling status level. The interior cooling status level reflects the cooling effect of the air conditioning system 10 in the vehicle; a higher interior cooling status level indicates a better cooling effect.

[0046] In one example, if the difference between the actual evaporator temperature T5 and the target evaporator temperature T4 is greater than the first parameter A, and the vehicle interior temperature T6 is higher than the permissible vehicle interior temperature T3, it indicates that the difference between the actual and target evaporator temperatures is significant, and the actual vehicle interior temperature exceeds the acceptable maximum interior temperature, meaning that the vehicle interior cooling effect is poor. In this case, the controller 50 can determine the vehicle interior cooling status level as the first vehicle interior cooling status level.

[0047] If the difference between the actual evaporator temperature T5 and the target evaporator temperature T4 is greater than the first parameter A, but the vehicle interior temperature T6 is lower than or equal to the permissible vehicle interior temperature T3, it indicates that the difference between the actual evaporator temperature and the target temperature is large, but the actual vehicle interior temperature is at an acceptable level. In this case, the controller 50 can determine the vehicle interior cooling status level as the second vehicle interior cooling status level.

[0048] If the difference between the actual evaporator temperature T5 and the target evaporator temperature T4 is greater than the second parameter a and less than or equal to the first parameter A, it indicates that the actual evaporator temperature is close to the target temperature. In this case, the controller 50 can determine the vehicle interior cooling status level as the third vehicle interior cooling status level.

[0049] If the difference between the actual evaporator temperature T5 and the target evaporator temperature T4 is less than or equal to the second parameter a, it indicates that the actual evaporator temperature has reached an acceptable level, meaning the vehicle interior cooling effect is good. At this time, the controller 50 can determine the vehicle interior cooling status level as the fourth vehicle interior cooling status level. In an exemplary embodiment of the present invention, the vehicle interior cooling status level is divided into four levels, but the present invention is not limited to this; the vehicle interior cooling status level can be divided into more or fewer levels depending on the circumstances.

[0050] When the cooling effect inside the vehicle is poor, the controller 50 can control the opening of the second expansion valve 32 on the refrigerant connection line 31 to be smaller, so as to prioritize the cooling of the vehicle interior and thus improve the comfort of the occupants. When the cooling effect inside the vehicle is good, the controller 50 can control the opening of the second expansion valve 32 according to the superheat of the battery cooler 30, so that the battery temperature is within the optimal operating temperature range of the battery.

[0051] After determining the vehicle interior cooling status level, the controller 50 can obtain the compressor request speed for battery cooling from the air conditioning unit 10. The compressor request speed for battery cooling refers to the compressor speed required when the battery needs cooling, based on the battery's operating conditions (e.g., battery temperature, battery heating rate, etc.). If the compressor request speed obtained for battery cooling is greater than or equal to the maximum compressor request speed, it indicates that the battery 22 needs rapid cooling. Situations requiring rapid cooling of the battery 22 include, but are not limited to, situations where the battery temperature is high, or where the battery temperature is not high but the heating rate is rapid. In this case, regardless of the vehicle interior cooling status level, the controller 50 can control the opening of the second expansion valve 32 to its maximum opening to rapidly cool the battery 22. In one example, the maximum compressor request speed can be 4000 rpm.

[0052] If the compressor speed requested for battery cooling is less than the maximum compressor speed requested, the controller 50 can control the opening of the second expansion valve 32 according to the vehicle cooling status level.

[0053] Specifically, when the vehicle interior cooling status level is the first vehicle interior cooling status level, the controller 50 can control the second expansion valve 32 to close, so that all the refrigerant in the refrigerant line 11 is used to cool the vehicle interior, thereby enabling the vehicle interior to cool down quickly.

[0054] When the vehicle interior cooling status level is the second vehicle interior cooling status level, the controller 50 can control the opening of the second expansion valve 32 to the minimum opening, so that most of the refrigerant in the refrigerant line 11 is used to cool the vehicle interior, while the remaining refrigerant can be used to cool the battery 22.

[0055] When the vehicle interior cooling status level is at the third or fourth level, the controller 50 can control the opening of the second expansion valve 32 between its minimum and maximum opening based on the superheat of the battery cooler 30. The controller 50 can obtain the superheat of the battery cooler 30 from a sensor located on the refrigerant branch line 31. The controller 50 can control the opening of the second expansion valve 32 to be positively correlated with the superheat of the battery cooler 30. In other words, the controller 50 can control the opening of the second expansion valve 32 to increase as the superheat of the battery cooler 30 increases.

[0056] The controller 50 can control the speed of the pump 23 according to the opening degree of the second expansion valve 32. The controller 50 can control the speed of the pump 23 to be proportional to the opening degree of the second expansion valve 32. In other words, the larger the opening degree of the second expansion valve 32, the greater the flow rate of refrigerant through the battery cooler 30. Correspondingly, the pump 23 needs to pump more coolant into the battery cooler 30 to ensure the cooling performance of the battery 22.

[0057] Specifically, when the second expansion valve 32 is closed, the controller 50 can set the pump speed level to the first speed level. When the vehicle interior cooling is ineffective and rapid cooling is required, the second expansion valve will be closed even if the compressor for battery cooling requests a certain speed, preventing the supply of refrigerant to the battery cooler. At this time, even if the coolant and refrigerant do not exchange heat in the battery cooler, the pump will still operate at the first speed level, allowing the coolant to circulate through the battery 22, thereby reducing the temperature difference inside the battery 22.

[0058] When the opening degree of the second expansion valve 32 is greater than or equal to the minimum opening degree and less than the first opening degree, the controller 50 can determine the speed level of the pump 23 as the second speed level. Similarly, when the opening degree of the second expansion valve 32 is greater than or equal to the first opening degree and less than the second opening degree, the controller 50 can determine the speed level of the pump 23 as the third speed level. When the opening degree of the second expansion valve 32 is greater than or equal to the second opening degree and less than the third opening degree, the controller 50 can determine the speed level of the pump 23 as the fourth speed level. When the opening degree of the second expansion valve 32 is greater than or equal to the third opening degree and less than the fourth opening degree, the controller 50 can determine the speed level of the pump 23 as the fifth speed level. When the opening degree of the second expansion valve 32 is greater than or equal to the fourth opening degree and less than or equal to the maximum opening degree, the controller 50 can determine the speed level of the pump 23 as the sixth speed level. In an exemplary embodiment of the present invention, the speed level of the pump 23 is divided into six levels, but the present invention is not limited to this, and the pump speed level can be divided into more or fewer levels depending on the pump.

[0059] A mapping table between the speed levels of pump 23 and the speed of pump 23 can be pre-stored in the controller 50. Therefore, after determining the speed level of pump 23, the controller 50 can determine the speed of pump 23 according to the mapping table and control pump 23 to operate at the corresponding speed, thereby cooling battery 22. In one example, the speed of pump 23 corresponding to the first speed level could be 1500 rpm, the speed of pump 23 corresponding to the second speed level could be 1700 rpm, the speed of pump 23 corresponding to the third speed level could be 2000 rpm, the speed of pump 23 corresponding to the fourth speed level could be 2500 rpm, the speed of pump 23 corresponding to the fifth speed level could be 3000 rpm, and the speed of pump 23 corresponding to the sixth speed level could be the pump's highest speed, such as 3500 rpm.

[0060] To ensure the cooling performance of battery 22, given the uneven temperature inside battery 22, the minimum required speed of pump 23 can be set based on the highest internal temperature of battery 22, and this minimum required speed increases as the highest internal temperature of battery 22 rises. The minimum required speed of pump 23 means that when pump 23 operates at this minimum speed, the battery temperature will not exceed the optimal operating temperature range. Therefore, pump 23 should operate at a speed greater than or equal to the minimum required speed to ensure the cooling performance of battery 22. To this end, after determining the speed of pump 23, controller 50 can obtain the highest internal temperature of battery 22 from battery cooling circuit 20 to determine the minimum required speed of pump 23, and compare the speed of pump 23 determined based on the opening of second expansion valve 32 with the minimum required speed of pump 23 determined based on the highest internal temperature of battery 22, determining the larger of the two as the required speed of pump 23. Furthermore, controller 50 can control the operation of pump 23 based on the determined required speed of pump 23.

[0061] In one example, when the highest internal temperature of battery 22 is below or equal to a first predetermined temperature (e.g., 35°C), the required minimum rotational speed of pump 23 can be set to 0. In this case, even if pump 23 is not running, the battery temperature will not exceed the optimal operating temperature range. When the highest internal temperature of battery 22 is above or equal to a second predetermined temperature (e.g., 44°C), the required minimum rotational speed of pump 23 can be set to the maximum rotational speed of pump 23. In this case, due to the higher battery temperature, if pump 23 is not running at its maximum speed, the battery temperature is likely to exceed the optimal operating temperature range.

[0062] The thermal management system of a vehicle according to an embodiment of the present invention will now be described with reference to examples. When the user turns on the cooling mode of the air conditioning unit 10, the controller 50 can obtain the ambient temperature T2 and the interior temperature T6 from the sensor unit 40. With the ambient temperature T2 at 30°C, and the user setting the air conditioning temperature T1 to 24°C, the controller 50 can determine, based on Table 1 above, that the first parameter A is 30, the second parameter a is 1.5, and the permissible interior temperature T3 is 35°C. The controller 50 can further obtain the evaporator target temperature T4 from the air conditioning unit 10; in this example, the evaporator target temperature T4 is 3°C.

[0063] In this situation, if the actual evaporator temperature T5 is higher than 33°C (i.e., the difference between the actual evaporator temperature T5 and the target evaporator temperature T4 is greater than the first parameter A), and if the interior temperature T6 is higher than 35°C (i.e., the interior temperature T6 is higher than the permissible interior temperature T3), then the controller 50 can determine the interior cooling status level as the first interior cooling status level. At this time, the controller 50 can close the second expansion valve 32 to ensure that all the refrigerant in the refrigerant line 11 is used to cool the interior, thereby achieving rapid cooling of the interior.

[0064] If the actual evaporator temperature T5 is higher than 33°C (i.e., the difference between the actual evaporator temperature T5 and the target evaporator temperature T4 is greater than the first parameter A), and if the interior temperature T6 is lower than or equal to 35°C (i.e., the interior temperature T6 is lower than or equal to the permissible interior temperature T3), then the controller 50 can determine the interior cooling status level as the second interior cooling status level. At this time, the controller 50 can control the opening of the second expansion valve 32 to its minimum opening, so that most of the refrigerant in the refrigerant line 11 is used to cool the interior, thereby ensuring the cooling performance of the interior.

[0065] If the actual evaporator temperature T5 is higher than 4.5℃ and lower than or equal to 33℃, that is, the difference between the actual evaporator temperature T5 and the target evaporator temperature T4 is greater than the second parameter a and less than or equal to the first parameter A, then the controller 50 can determine the vehicle interior cooling status level as the third vehicle interior cooling status level. At this time, the controller 50 can control the opening degree of the second expansion valve 32 between the minimum and maximum opening degree according to the superheat of the battery cooler 30.

[0066] If the actual evaporator temperature T5 is less than or equal to 4.5℃, that is, the difference between the actual evaporator temperature T5 and the target evaporator temperature T4 is less than or equal to the second parameter a, then the controller 50 can determine the vehicle interior cooling status level as the fourth vehicle interior cooling status level. At this time, the controller 50 can control the opening degree of the second expansion valve 32 between the minimum opening degree and the maximum opening degree according to the superheat of the battery cooler 30.

[0067] In addition, to ensure the cooling performance of the battery 22, when the highest internal temperature of the battery 22 is higher than or equal to 44°C, the controller 50 can control the opening of the second expansion valve 32 to the maximum opening, regardless of the vehicle's cooling status level, so that the pump 23 can run at the highest speed.

[0068] Figure 3 A flowchart illustrating a control method for a vehicle's thermal management system according to an exemplary embodiment of the present invention. Figure 3 The control method shown can be executed by the controller 50 described above.

[0069] like Figure 3As shown, in step S101, the controller 50 can obtain the operating status of the air conditioning unit 10 from the air conditioning unit 10 to determine whether the cooling mode of the air conditioning unit 10 is turned on.

[0070] When it is determined that the cooling mode of the air conditioning unit 10 is turned on (step S101 is "yes"), in step S102, the controller 50 can obtain the ambient temperature T2 and the vehicle interior temperature T6 from the sensor unit 40, and obtain the air conditioning set temperature T1, the evaporator target temperature T4 and the evaporator actual temperature T5 from the air conditioning unit.

[0071] In step S103, the controller 50 can determine a first parameter A, a second parameter a, and an allowable interior temperature T3 based on the acquired air conditioning set temperature T1 and ambient temperature T2. The controller 50 can also compare the allowable interior temperature T3 with the interior temperature T6. Furthermore, the controller 50 can compare the difference between the actual evaporator temperature T5 and the target evaporator temperature T4 with the first parameter A and / or the second parameter a. Therefore, the controller 50 can determine the interior cooling status level based on the comparison results.

[0072] In step S104, the controller 50 can obtain the compressor requested speed for battery cooling from the air conditioning unit 10 and determine whether the compressor requested speed for battery cooling is greater than or equal to the maximum compressor requested speed.

[0073] When it is determined that the compressor speed required for battery cooling is less than the maximum compressor speed required (step S104 is "No"), in step S105, the controller 50 can determine the opening degree of the expansion valve 32 of the battery cooler 30 based on the determined in-vehicle cooling state level. When the in-vehicle cooling state level is the first in-vehicle cooling state level, the controller 50 can control the expansion valve 32 of the battery cooler 30 to be closed. When the in-vehicle cooling state level is the second in-vehicle cooling state level, the controller 50 can control the expansion valve 32 of the battery cooler 30 to be at its minimum opening degree. When the in-vehicle cooling state level is the third or fourth in-vehicle cooling state level, the controller 50 can control the expansion valve 32 of the battery cooler 30 between its minimum and maximum opening degree based on the superheat of the battery cooler 30.

[0074] When it is determined that the compressor speed requested for battery cooling is greater than or equal to the maximum compressor speed requested (step S104 is "Yes"), in step S106, the controller 50 can control the expansion valve 32 of the battery cooler 30 to the maximum opening.

[0075] After determining the opening degree of the expansion valve 32 of the battery cooler 30, in step S107, the controller 50 can determine the speed level of the pump 23 for the battery 22 according to the opening degree of the expansion valve of the battery cooler, and then the controller 50 can determine the speed of the pump for the battery corresponding to the speed level of the pump for the battery according to the mapping table.

[0076] In step S108, the controller 50 can obtain the highest temperature inside the battery 22 from the battery cooling circuit 20, thereby determining the minimum required speed of the pump for the battery.

[0077] In step S109, the controller 50 can compare the determined speed of the pump for the battery with the required minimum speed of the pump for the battery to determine whether the speed of the pump for the battery is less than the required minimum speed of the pump for the battery.

[0078] When it is determined that the speed of the pump used for the battery is less than the required minimum speed of the pump used for the battery (step S109 is "Yes"), in step S110, the controller 50 can control the pump used for the battery to operate at the required minimum speed determined in step S108.

[0079] When it is determined that the speed of the pump used for the battery is greater than or equal to the minimum required speed of the pump used for the battery (step S109 is "No"), in step S111, the controller 50 can control the pump used for the battery to operate at the speed determined in step S107.

[0080] The vehicle thermal management system and its control method according to an exemplary embodiment of the present invention consider not only the cooling state of the battery but also the cooling state inside the vehicle when cooling the battery, thereby rationally allocating the cooling capacity of the vehicle's thermal management system.

[0081] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and descriptive purposes. It is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed, and it will be apparent that various modifications and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described to explain the specific principles of the invention and its practical application, thereby enabling others skilled in the art to implement and utilize various exemplary embodiments of the invention, as well as their different alternatives and modifications. The scope of the invention is intended to be defined by the appended claims and their equivalents.

Claims

1. A thermal management system for a vehicle, comprising: A sensor unit configured to sense ambient temperature and vehicle interior temperature; An air conditioning unit includes a compressor, a condenser, a first expansion valve, and an evaporator connected via refrigerant lines, and the air conditioning unit is configured to cool the vehicle interior; A battery cooling circuit includes a battery, a pump, and a battery cooler connected via a battery cooling line, and the battery cooling circuit is configured to cool the battery, wherein the battery cooler is connected to a refrigerant line via a refrigerant connection line to receive refrigerant from the refrigerant line and use the refrigerant to cool the battery, and further includes a second expansion valve disposed on the refrigerant connection line upstream of the battery cooler; as well as The controller is configured as follows: The ambient temperature, vehicle interior temperature, air conditioning set temperature, evaporator target temperature, and evaporator actual temperature are obtained from the sensor unit and the air conditioning unit, respectively. The vehicle interior cooling status level is determined based on the obtained ambient temperature, vehicle interior temperature, air conditioning set temperature, evaporator target temperature, and evaporator actual temperature. The opening degree of the second expansion valve is determined based on the determined in-vehicle cooling status level. Determine the pump speed rating based on the determined opening degree of the second expansion valve; Determine the pump speed based on the determined pump speed rating; The pump's operation is controlled according to its rotational speed to cool the battery.

2. The vehicle thermal management system according to claim 1, wherein, The controller is configured as follows: Based on the obtained ambient temperature and air conditioning set temperature, determine the first parameter and the second parameter which is less than the first parameter; When the difference between the actual evaporator temperature and the target evaporator temperature is greater than the first parameter and the interior temperature is higher than the allowable interior temperature, the interior cooling status level is determined as the first interior cooling status level. When the difference between the actual evaporator temperature and the target evaporator temperature is greater than the first parameter and the interior temperature is lower than or equal to the allowable interior temperature, the interior cooling status level is determined to be the second interior cooling status level. When the difference between the actual evaporator temperature and the target evaporator temperature is greater than the second parameter and less than or equal to the first parameter, the vehicle interior cooling status level is determined to be the third vehicle interior cooling status level. When the difference between the actual evaporator temperature and the target evaporator temperature is less than or equal to the second parameter, the vehicle interior cooling status level is determined to be the fourth vehicle interior cooling status level.

3. The vehicle thermal management system according to claim 2, wherein, The controller is configured as follows: Obtain the compressor speed request from the air conditioning unit for battery cooling; When the compressor speed requested for battery cooling is greater than or equal to a predetermined value, the opening of the second expansion valve is controlled to the maximum opening. When the requested compressor speed for battery cooling is less than a predetermined value, the opening degree of the second expansion valve is determined based on the determined in-vehicle cooling status level.

4. The vehicle thermal management system according to claim 3, wherein, The controller is configured as follows: When the vehicle interior cooling status level is the first vehicle interior cooling status level, close the second expansion valve; When the vehicle interior cooling status level is the second vehicle interior cooling status level, the opening degree of the second expansion valve is controlled to the minimum opening degree. When the vehicle interior cooling status level is the third or fourth vehicle interior cooling status level, the opening of the second expansion valve is controlled according to the overheating of the battery cooler.

5. The vehicle thermal management system according to claim 4, wherein, The controller is configured as follows: When the second expansion valve is closed, the pump speed level is set to the first speed level; When the opening degree of the second expansion valve is greater than or equal to the minimum opening degree and less than the first opening degree, the pump speed level is determined as the second speed level, and the first opening degree is greater than the minimum opening degree; When the opening degree of the second expansion valve is greater than or equal to the first opening degree and less than the second opening degree, the pump speed level is determined to be the third speed level, where the second opening degree is greater than the first opening degree; When the opening degree of the second expansion valve is greater than or equal to the second opening degree and less than the third opening degree, the pump speed level is determined to be the fourth speed level, wherein the third opening degree is greater than the second opening degree; When the opening degree of the second expansion valve is greater than or equal to the third opening degree and less than the fourth opening degree, the pump speed level is determined to be the fifth speed level, wherein the fourth opening degree is greater than the third opening degree; When the opening degree of the second expansion valve is greater than or equal to the fourth opening degree and less than or equal to the maximum opening degree, the pump speed level is determined to be the sixth speed level, wherein the fourth opening degree is less than the maximum opening degree.

6. The vehicle thermal management system according to claim 5, wherein, The controller is configured as follows: The battery temperature is obtained from the battery cooling circuit, and the minimum required pump speed is determined based on the obtained battery temperature. The required speed of the pump is determined by the larger of the speed determined according to the pump's speed class and the minimum required speed of the pump, and the operation of the pump is controlled according to the determined required speed.

7. A control method for a vehicle's thermal management system, comprising: Acquire ambient temperature, vehicle interior temperature, air conditioning set temperature, evaporator target temperature, and evaporator actual temperature; The vehicle interior cooling status level is determined based on the obtained ambient temperature, vehicle interior temperature, air conditioning set temperature, evaporator target temperature, and evaporator actual temperature. Determine the opening degree of the battery cooler's expansion valve based on the determined in-vehicle cooling status level; Determine the pump speed rating for the battery based on the determined opening degree of the expansion valve of the battery cooler; Determine the pump speed for the battery based on the determined pump speed rating for the battery. The operation of the pump used for the battery is controlled according to the pump speed to cool the battery.

8. The control method according to claim 7, wherein, Determining the vehicle's in-vehicle cooling status includes: Based on the obtained ambient temperature and air conditioning set temperature, determine the first parameter and the second parameter which is less than the first parameter; When the difference between the actual evaporator temperature and the target evaporator temperature is greater than the first parameter and the interior temperature is higher than the allowable interior temperature, the interior cooling status level is determined as the first interior cooling status level. When the difference between the actual evaporator temperature and the target evaporator temperature is greater than the first parameter and the interior temperature is lower than or equal to the allowable interior temperature, the interior cooling status level is determined to be the second interior cooling status level. When the difference between the actual evaporator temperature and the target evaporator temperature is greater than the second parameter and less than or equal to the first parameter, the vehicle interior cooling status level is determined to be the third vehicle interior cooling status level. When the difference between the actual evaporator temperature and the target evaporator temperature is less than or equal to the second parameter, the vehicle interior cooling status level is determined to be the fourth vehicle interior cooling status level.

9. The control method according to claim 8, wherein, Determining the opening degree of the expansion valve of the battery cooler includes: Obtain the compressor speed request for battery cooling; When the requested compressor speed for battery cooling is greater than or equal to a predetermined value, the opening of the expansion valve of the battery cooler is controlled to the maximum opening. When the requested compressor speed for battery cooling is less than a predetermined value, the opening degree of the battery cooler's expansion valve is determined based on the determined in-vehicle cooling status level.

10. The control method according to claim 9, wherein, Determining the opening degree of the expansion valve of the battery cooler includes: When the vehicle interior cooling status level is the first vehicle interior cooling status level, close the expansion valve of the battery cooler; When the vehicle interior cooling status level is the second vehicle interior cooling status level, the opening of the battery cooler expansion valve is controlled to the minimum opening. When the vehicle interior cooling status level is the third or fourth level, the opening of the battery cooler expansion valve is controlled according to the overheating of the battery cooler.

11. The control method according to claim 10, wherein, Determining the pump speed rating for the battery includes: When the expansion valve of the battery cooler is closed, the speed level of the pump used for the battery is determined as the first speed level; When the opening degree of the expansion valve of the battery cooler is greater than or equal to the minimum opening degree and less than the first opening degree, the speed level of the pump used for the battery is determined as the second speed level, wherein the first opening degree is greater than the minimum opening degree; When the opening degree of the expansion valve of the battery cooler is greater than or equal to the first opening degree and less than the second opening degree, the speed level of the pump used for the battery is determined to be the third speed level, wherein the second opening degree is greater than the first opening degree. When the opening degree of the expansion valve of the battery cooler is greater than or equal to the second opening degree and less than the third opening degree, the speed level of the pump used for the battery is determined to be the fourth speed level, wherein the third opening degree is greater than the second opening degree. When the opening degree of the expansion valve of the battery cooler is greater than or equal to the third opening degree and less than the fourth opening degree, the speed level of the pump used for the battery is determined to be the fifth speed level, wherein the fourth opening degree is greater than the third opening degree. When the opening degree of the expansion valve of the battery cooler is greater than or equal to the fourth opening degree and less than or equal to the maximum opening degree, the speed level of the pump used for the battery is determined to be the sixth speed level, wherein the fourth opening degree is less than the maximum opening degree.

12. The control method according to claim 11, wherein, Determining the pump speed for the battery includes: Obtain battery temperature; Based on the obtained battery temperature, determine the minimum required speed of the pump used for the battery; The required speed of the pump for the battery is determined by the larger of the speed determined according to the speed class of the pump for the battery and the minimum required speed of the pump for the battery. The operation of the pump used for the battery is controlled according to the determined required speed of the pump used for the battery.

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