Vehicle thermal management system

Abstract

This invention relates to a vehicle thermal management system that reliably supplies liquid refrigerant when the coolant used to cool the battery that supplies power to the vehicle's drive motor is cooled by the refrigerant in the refrigeration cycle of an air conditioning unit. When the front and rear air conditioning units (28F, 28R) are operating in dehumidification and heating mode and cooling the battery (18), the refrigeration cycle (30) operates in cooling mode, supplying liquid refrigerant to the front and rear evaporators (42F, 42R) and the battery cooling heat exchanger (41). The heating circuit (32) supplies high-temperature liquid heated by the electric heater (38) to the front and rear heater cores (44F, 44R). Air cooled by the front and rear evaporators is heated by the front and rear heater cores and supplied to the passenger compartment (20). Battery coolant cooled by the battery cooling heat exchanger is delivered to the battery to cool it.

Description

Technical Field

[0001] This invention relates to a thermal management system for air conditioning in the passenger compartment of a vehicle and for temperature management of onboard equipment. Background Technology

[0002] Patent Document 1 discloses a vehicle equipped with a front air conditioning unit (2) that supplies temperature- and humidity-controlled air to the front of the passenger compartment and a rear air conditioning unit (3) that supplies temperature- and humidity-controlled air to the rear. The front and rear air conditioning units (2, 3) are equipped with heater cores (27, 48) and evaporators (26, 47), respectively, and are capable of independently regulating the air at the front and rear of the passenger compartment.

[0003] In addition, there are known vehicle air conditioning devices that operate in a dehumidification and heating mode in a defined area determined by the relationship between the external gas temperature and the blow-out temperature from the air conditioning unit, where the air is dehumidified by cooling with an evaporator and heated with a heater core.

[0004] It should be noted that the reference numerals in parentheses above are the reference numerals used in Patent Document 1 below, and are not related to the reference numerals used in the description of the embodiments of this application.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2018-103643 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] When using the refrigeration cycle of the air conditioning unit to cool the battery that supplies power to the electric motor driving the vehicle, if refrigerant is supplied to both the front and rear air conditioning units and for battery cooling, adequate air conditioning and battery cooling may not be achieved. In particular, during dehumidification and heating operation, the refrigerant supplied to the evaporators of the front and rear air conditioning units and the battery cooling heat exchangers may sometimes be in a gas-liquid two-phase state. Therefore, it may be impossible to adequately control the flow rate of refrigerant supplied to each evaporator and battery cooling heat exchanger, resulting in unsatisfactory air conditioning and battery cooling performance.

[0010] This invention provides a vehicle thermal management system that can achieve the required air conditioning performance and battery cooling performance in dehumidification operation areas.

[0011] Methods for solving problems

[0012] The vehicle thermal management system of the present invention includes: a front air conditioning unit for air conditioning the front space of the vehicle's passenger compartment; a rear air conditioning unit for air conditioning the rear space of the passenger compartment; a battery cooling circuit for circulating coolant that supplies power to the electric motor for vehicle drive; a refrigeration cycle circuit for supplying refrigerant to the front and rear air conditioning units and for supplying refrigerant to a battery cooling heat exchanger that exchanges heat between the coolant and refrigerant in the battery cooling circuit; and a heating circuit for generating a high-temperature liquid using a heat source or the refrigerant in the refrigeration cycle circuit, and supplying the high-temperature liquid to the front and rear air conditioning units. The dehumidification and heating operation zone is defined by the temperature control target of the air supplied from the front and rear air conditioning units, namely, the required outlet temperature and the outside gas temperature. In the dehumidification and heating operation zone, when the front and rear air conditioning units are in operation and the battery cooling requirement is above a first required value, the refrigeration cycle circuit operates in cooling mode, supplying refrigerant to the front and rear air conditioning units and the battery cooling heat exchanger. In addition, the heating circuit uses a heat source to generate a high-temperature liquid. Furthermore, the battery cooling circuit uses coolant cooled by the refrigerant in the refrigeration cycle within the battery cooling heat exchanger to cool the battery.

[0013] By operating the refrigeration cycle, the refrigerant is only in the liquid phase. This allows liquid refrigerant to be supplied to the front air conditioning unit, the rear air conditioning unit, and the heat exchanger for battery cooling.

[0014] In the aforementioned vehicle thermal management system, when the battery cooling requirement is higher than a second requirement value (which is higher than a first requirement value) and the battery charge is lower than a specified value, the refrigerant supply from the cooling cycle circuit to the front and rear air conditioning units can be stopped. By suppressing the power consumed by the cooling cycle circuit, the driving range achieved by the electric motor can be extended.

[0015] In the aforementioned vehicle thermal management system, the refrigeration cycle loop can have a compressor that compresses the refrigerant and an outdoor heat exchanger that exchanges heat with the external gas. During refrigeration operation, all the refrigerant compressed and sprayed by the compressor passes through the outdoor heat exchanger and is liquefied.

[0016] In the aforementioned vehicle thermal management system, the heat source for the heating circuit can be either the vehicle's engine or the electric heater.

[0017] Invention Effects

[0018] In the dehumidification and heating operation zone, when both the front and rear air conditioning units are operating and battery cooling is required, refrigerant in liquid phase can be supplied to the front and rear air conditioning units and the battery cooling heat exchanger. Compared to supplying refrigerant in a gas-liquid two-phase state, the amount of refrigerant supplied to the front and rear air conditioning units and the battery cooling heat exchanger can be appropriately adjusted. Attached Figure Description

[0019] Figure 1 This is a diagram showing a schematic structure of a vehicle equipped with the thermal management system of this embodiment.

[0020] Figure 2 This is a diagram showing the front air conditioning unit and its control section.

[0021] Figure 3 This is a diagram schematically illustrating the structure of the thermal management system of this embodiment.

[0022] Figure 4 This is a diagram showing the conditions for specifying the operating mode of an air conditioning unit.

[0023] Figure 5 It is a diagram showing the operating status of the thermal management system, especially the status during heating operation based on engine coolant.

[0024] Figure 6 It is a diagram showing the operating status of the thermal management system, especially the status during heating operation based on electric heaters.

[0025] Figure 7 It is a diagram showing the operating status of the thermal management system, especially the status of the heat pump during heating operation based on the refrigeration cycle loop.

[0026] Figure 8 It is a diagram showing the operating status of the thermal management system, especially the status during refrigeration operation.

[0027] Figure 9 It is a diagram showing the operating status of the thermal management system, especially the status when the parallel dehumidification and heating are in operation.

[0028] Figure 10 It is a diagram showing the operating status of the thermal management system, especially the status during inline dehumidification and heating operation.

[0029] Figure 11 It is a diagram showing the operating status of the thermal management system, especially showing the status when the front and rear air conditioning units in the dehumidification and heating zone are operating and cooling the battery.

[0030] Figure 12It is a diagram showing the operating status of the thermal management system, especially showing the status when the battery cooling requirement is strong and the battery charge is low in the dehumidification and heating zone.

[0031] Figure 13 This is a diagram illustrating a portion of the control flow of a thermal management system. Detailed Implementation

[0032] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a schematic diagram showing the general structure of the thermal management system 12 of the vehicle 10. The vehicle 10 is equipped with an engine 14 as the prime mover for driving the vehicle 10, and two electric motors 16F and 16R that drive the front and rear wheels respectively. The vehicle 10 is equipped with a battery 18 that supplies power to the electric motors 16F and 16R and charges with the electricity generated by the electric motors 16F and 16R during braking. The vehicle may also be a vehicle equipped with only one electric motor that drives either the front or rear wheels. Furthermore, the vehicle may also be a vehicle without an engine that uses an electric motor to drive one or both of the front and rear wheels. For simplicity, the electric motors 16F and 16R will be referred to as electric motor 16.

[0033] The thermal management system 12 cools the engine 14, electric motor 16, and battery 18, and also regulates the airflow in the passenger compartment 20. The cooling system for the engine 14 includes an engine radiator 22 that dissipates heat generated by the engine via engine coolant. The engine coolant flows in piping connecting the engine 14 and the engine radiator 22, circulating between the engine 14 and the engine radiator 22. Figure 1 The piping connecting the engine 14 and the engine radiator 22 is omitted. The cooling system for the electric motor 16 includes an electric motor radiator 24 that dissipates heat generated by the electric motor 16 via electric motor coolant. The electric motor coolant flows in the piping connecting the electric motor 16 and the electric motor radiator 24 and circulates between the electric motor 16 and the electric motor radiator 24. Figure 1 The piping connecting the motor 16 and the motor radiator 24 is omitted in the text.

[0034] The thermal management system 12 includes an air conditioning unit 26 for conditioning the air in the passenger compartment 20. The air conditioning unit 26 has an air conditioning unit 28 that supplies air with adjusted temperature and humidity to the passenger compartment 20. The air conditioning unit 28 includes a front air conditioning unit 28F for conditioning the air in the front seat area of ​​the passenger compartment 20 and a rear air conditioning unit 28R for conditioning the air in the rear seat area. The air conditioning unit 26 includes a refrigeration cycle loop 30 that supplies refrigerant to the air conditioning unit 28 and a heating loop 32 that supplies heated liquid to the air conditioning unit 28. The refrigeration cycle loop 30 includes a compressor 34 that compresses the refrigerant and an outdoor condenser 36 that liquefies the refrigerant compressed by the compressor 34 by cooling it with external gas. The compressor 34 may be an electric compressor driven by an electric motor, and the output of the compressor 34 can be adjusted by controlling the speed of the electric motor. The heating loop 32 includes an electric heater 38 as a heat source. The refrigeration cycle loop 30 and the heating loop 32, along with other cooling systems of the thermal management system 12, will be described in more detail later.

[0035] The thermal management system 12 also includes a battery cooling circuit 40 for cooling the battery 18. The battery cooling circuit 40 cools the battery 18 by supplying battery coolant, which has been cooled by the refrigerant in the refrigeration cycle circuit 30 in the battery cooling heat exchanger 41, to the battery 18.

[0036] Figure 2This diagram schematically illustrates the structure of the front air conditioning unit 28F. The front air conditioning unit 28F includes a front evaporator 42F, which is a component of the refrigeration cycle circuit 30, and a front heater core 44F, which is a component of the heating circuit 32. It also includes an air conditioning housing 46 that houses the front evaporator 42F and the front heater core 44F. The air conditioning housing 46 has an air inlet 48 for introducing air into the air conditioning housing 46. The air inlet 48 includes an internal gas inlet 48C for introducing air into the passenger compartment 20 and an external gas inlet 48E for introducing air from outside the vehicle. Additionally, the air conditioning housing 46 has an air outlet 50 for discharging conditioned air towards designated areas. The air outlet 50 includes a head outlet 50H for discharging airflow to the head and surrounding area of ​​the front seat occupant, a foot outlet 50F for discharging airflow to the feet of the front seat occupant, and a defrost outlet 50D for discharging airflow to the interior surface of the windshield. Airflow from the head outlet 50H passes through ducts within the instrument panel (not shown) and exits through multiple air outlets formed in the instrument panel to the head and surrounding area of ​​the front seat occupant in the passenger compartment 20. Additionally, airflow from the foot outlet 50F exits directly or through ducts within the instrument panel to the feet of the front seat occupant. Furthermore, airflow from the defrost outlet 50D exits through ducts within the instrument panel and exits from an outlet located opposite the lower edge of the windshield. The front air conditioning unit 28F has a blower 52 disposed upstream of the air conditioning housing 46. The blower 52 generates airflow from the air inlet 48 to the air outlet 50.

[0037] An internal / external gas switching gate 54 is provided at the confluence of the flow path from the internal gas inlet 48C and the flow path from the external gas inlet 48E. The internal / external gas switching gate 54 can rotate between a position where the internal gas inlet 48C is closed and a position where the external gas inlet 48E is closed, adjusting the mixing ratio of the internal and external gases according to the rotation angle. An air mixing gate 56 is provided between the front evaporator 42F and the front heater core 44F. The air mixing gate 56 rotates to adjust the amount of air passing through the front evaporator 42F and the front heater core 44F. Corresponding to each air outlet 50, an outlet gate 58 is provided to open and close the air outlet 50. Specifically, a head outlet door 58H is provided at the head outlet 50H, a foot outlet door 58F is provided at the foot outlet 50F, and a defrost outlet door 58D is provided at the defrost outlet 50D. The air volume from each outlet 50 is adjusted by the opening degree of each outlet door 58.

[0038] The air volume of the blower 52, the rotation angle of the internal and external gas switching door 54 and the air mixing door 56, and the opening degree of each outlet door 58 are controlled by the control unit 60. The control unit 60 controls the rotation angle of the internal and external gas switching door 54 and the air mixing door 56, the opening degree of each outlet door 58, and the air volume of the blower 52 based on the conditions and environmental conditions set by the occupant. The occupant uses the temperature setting switch 62 to set the desired temperature and uses the outlet switching switch 64 to set the desired air outlet 50. Regarding the selection of the air outlet 50, it is possible to select the blowing mode of any one of the air outlets 50H, 50F, and 50D individually, or the blowing mode of blowing air from both the head outlet 50H and the foot outlet 50F. In addition, the occupant can use the automatic air conditioning switch 66 to set the automatic air conditioning mode. In this case, the control unit 60 selects the air outlet 50 to deliver air according to a predetermined procedure based on the desired temperature and environmental conditions. The control unit 60 is input with the air temperature of the passenger compartment 20 detected by the room temperature sensor 68, the outside gas temperature detected by the outside gas temperature sensor 70, the liquid temperature of the heating circuit 32 detected by the liquid temperature sensor 72, and the amount of sunlight entering the passenger compartment 20 detected by the sunlight sensor 74. In addition, the control unit 60 is input with the temperature of the air that has just passed through the front evaporator 42F (evaporator outlet temperature), which is detected by the evaporator outlet temperature sensor 76 located immediately behind the front evaporator 42F.

[0039] The rear air conditioning unit 28R has a structure substantially the same as the front air conditioning unit 28F, and is not shown in the figure. The rear air conditioning unit 28R houses the rear evaporator 42R and the rear heater core 44R (see figure). Figure 1 The air conditioning unit 28R has an air inlet and an air outlet. In the rear air conditioning unit 28R, the air inlet may not include an external gas inlet, and the air outlet may not include a defrost outlet. The rear air conditioning unit 28R, like the front air conditioning unit 28F, can supply conditioned air to one or both sides of the rear passenger's head or surrounding area and feet.

[0040] The rear air conditioning unit 28R can be switched on and off by the occupant. By operating the rear air conditioning switch 67, the control unit 60 will activate both the front air conditioning unit 28F and the rear air conditioning unit 28R. The front air conditioning unit 28F and the rear air conditioning unit 28R can independently set the temperature and select the airflow mode.

[0041] The control unit 60 is a processing device that controls the air conditioning unit 26 according to a prescribed procedure and operates in a manner that achieves the temperature and air supply mode desired by the occupants based on the aforementioned temperature, sunlight, etc.

[0042] Figure 3This is a schematic diagram illustrating the structure of the thermal management system 12. The same reference numerals are used for the components already described. In addition to the compressor 34, outdoor condenser 36, front and rear evaporators 42F and 42R already described, the refrigeration cycle loop 30 also includes a liquid-cooled condenser 78 for heat exchange with the heating loop 32 and a battery cooling heat exchanger 41 for heat exchange with the battery cooling loop 40. In the refrigeration cycle loop 30, electrically operated expansion valves 84 and 86 with adjustable openings are provided upstream of the front evaporator 42F and the battery cooling heat exchanger 41, respectively, and an expansion valve 88 and a solenoid valve 90 are provided upstream of the rear evaporator 42R. The electrically operated expansion valves 84 and 86 cannot be completely closed; even at their minimum opening, a small amount of refrigerant is supplied to the front evaporator 42F and the battery cooling heat exchanger 41. On the other hand, the refrigerant supply to the rear evaporator 42R can be completely stopped by closing the solenoid valve 90. Furthermore, a heating expansion valve 92 is provided upstream of the outdoor condenser 36. The heating expansion valve 92 is adjustable in opening and can be an electrically operated expansion valve. When the refrigeration cycle 30 is in heating operation, the refrigerant expands through the reduced opening of the heating expansion valve 92, vaporizing and absorbing heat in the outdoor condenser 36. Thus, during heating operation, the outdoor condenser 36 functions as an evaporator. When the refrigeration cycle 30 is in cooling operation, the heating expansion valve 92 is fully open, allowing only refrigerant to pass through. The capacity of the refrigeration cycle 30 is adjusted by regulating the output of the compressor 34 and the opening of each expansion valve 84, 86, 88, and 92.

[0043] The refrigeration cycle loop 30 has a first bypass flow path 94 arranged side-by-side with respect to the front and rear evaporators 42F, 42R and the battery cooling heat exchanger 41. The refrigerant bypasses the front and rear evaporators 42F, 42R and the battery cooling heat exchanger 41 by passing through the first bypass flow path 94. Additionally, the refrigeration cycle loop 30 has a second bypass flow path 96 arranged side-by-side with the outdoor condenser 36, allowing the refrigerant to bypass the outdoor condenser 36 by passing through the second bypass flow path 96.

[0044] The battery cooling circuit 40 includes a battery 18, a battery cooling heat exchanger 41, and a battery cooling circuit pump 98 that circulates coolant between the battery 18 and the battery cooling heat exchanger 41. The battery 18 is cooled by supplying coolant cooled by the battery cooling heat exchanger 41 to the battery 18. A battery temperature sensor 100 for detecting the temperature of the battery 18 and a charge sensor 102 for detecting the charge level of the battery 18 are provided on the battery 18. The cooling requirement level of the battery 18 is determined based on factors such as the battery temperature, and the battery cooling circuit 40 is controlled accordingly. The charge sensor 102 continuously monitors the power input and output relative to the battery 18, and calculates the current charge level by accumulating the input and output power.

[0045] The heating circuit 32 includes an electric heater 38, front and rear heater cores 44F and 44R, a liquid-cooled condenser 78, and a heating circuit pump 104 for conveying high-temperature liquid. The heating circuit pump 104 circulates the circulating liquid around the electric heater 38, the front and rear heater cores 44F and 44R, and the liquid-cooled condenser 78. The liquid-cooled condenser 78 uses the high-temperature refrigerant compressed by the compressor 34 of the refrigeration circuit 30 to heat the circulating liquid in the heating circuit 32, generating a high-temperature liquid. The circulating liquid, i.e., the high-temperature liquid, heated by the electric heater 38 or the liquid-cooled condenser 78, is conveyed to the front and rear heater cores 44F and 44R. Furthermore, the heating circuit 32 shares a heating / cooling liquid with the engine cooling circuit 106, allowing the engine 14 to be used as a heat source. Whether the high-temperature liquid conveyed to the front and rear heater cores 44F and 44R is supplied from the engine 14 side or from the electric heater 38 and the liquid-cooled condenser 78 is determined by the operation of the three-way valve 108.

[0046] The engine cooling circuit 106 includes an engine 14 and an engine radiator 22, and also includes an engine cooling circuit pump 110 that circulates engine coolant between the engine 14 and the engine radiator 22. The engine cooling circuit 106 includes a radiator bypass flow path 112 arranged parallel to the engine radiator 22, enabling engine coolant circulation around the engine radiator 22. During preheating when the engine 14 has cooled down, the engine cooling circuit 106 does not deliver engine coolant to the engine radiator 22, but instead circulates it through the radiator bypassing the flow path 112, thereby enabling the engine coolant temperature to be raised earlier. As mentioned above, the engine coolant can share the fluid with the heating circuit 32.

[0047] The flow paths of the refrigerant or fluid in the refrigeration cycle circuit 30, heating circuit 32, battery cooling circuit 40, and engine cooling circuit 106 can be modified according to specified conditions. In addition to the three-way valve 108 and solenoid valve 90 already described, the modification of the refrigerant or fluid flow paths is achieved by the operation of multiple valves (not shown) appropriately installed in each circuit. The opening and closing of these valves and the control of their opening degree can be controlled by the control unit 60. Furthermore, the control unit 60 controls the output of the compressor 34, the discharge flow rate of the battery cooling circuit pump 98, and the discharge flow rate of the heating circuit pump 104 as required.

[0048] The thermal management system 12 operates in some operating modes corresponding to specified conditions. These specified conditions are determined, for example, based on the following: the external gas temperature, the temperature of the airflow blown from the air conditioning unit 26 based on the occupants' requirements (required blowing temperature), and the cooling requirements and charge capacity of the battery 18.

[0049] Figure 4 This diagram illustrates an example of the conditions governing the operation modes of the thermal management system 12, particularly the operation mode of the air conditioning unit 26. In the heating zone H, where the external gas temperature is lower than a specified air temperature T1 (e.g., 0°C), the thermal management system 12 operates in heating mode, i.e., heating operation. Conversely, in the cooling zone C, where the external gas temperature is higher than the specified air temperature T1, a lower required outlet temperature is needed, and a large difference between the outlet temperature and the external gas temperature is required, the thermal management system 12 operates in cooling mode, i.e., cooling operation. In the dehumidifying heating zones Dp and Ds, located between the heating zone H and the cooling zone C, the thermal management system 12 operates in a dehumidifying heating mode where the air drawn into the air conditioning unit 28 is first cooled and dehumidified, then heated to the required outlet temperature, i.e., dehumidifying heating operation. The dehumidifying heating zones are further divided into parallel dehumidifying heating zones Dp and linear dehumidifying heating zones Ds. The thermal management system 12 operates in parallel dehumidification and heating mode in the parallel dehumidification and heating zone Dp, and in linear dehumidification and heating mode Ds. Parallel dehumidification and heating operation is an enhanced heating mode in the zone compared to linear dehumidification and heating operation. Furthermore, when the required airflow temperature of the front air conditioning unit 28F and the rear air conditioning unit 28R can be independently set, the required airflow temperature of one of the air conditioning units 28, such as the front air conditioning unit 28F, can be used as a factor in defining the operating mode. Alternatively, the required airflow temperature of the air conditioning unit 28 set to a lower temperature can be used as a factor in defining the operating mode. The operation of the thermal management system 12 under each operating mode will be explained below.

[0050] Figures 5-7This is a diagram showing the operating status of the thermal management system 12 in the heating zone H. In the following description, unless otherwise specified, the front heater core 44F and the rear heater core 44R are collectively referred to as heater core 44.

[0051] Figure 5 This diagram illustrates the operating state of the engine 14 when the coolant temperature is sufficiently high. When the engine coolant temperature is high, a portion of the engine coolant circulated by the engine cooling circuit pump 110 is supplied to the heater core 44. Engine coolant can be supplied to either or both of the front and rear heater cores 44F and 44R via occupant operation.

[0052] Figure 6 This diagram illustrates the operation when the engine coolant temperature is low. When the engine coolant temperature is low, the electric heater 38 generates high-temperature liquid, which is supplied to the heater core 44 by the heating circuit pump 104. The high-temperature liquid from the electric heater 38 can be supplied to either or both of the front and rear heater cores 44F and 44R via occupant operation. Furthermore, for vehicles that operate solely using the electric motor 16 without an engine 14, heating is provided by the electric heater 38 or by the heat pump operation of the cooling cycle circuit 30 described below.

[0053] Figure 7 This diagram illustrates the operating state of the refrigeration cycle circuit 30 heat pump for heating. The refrigerant, compressed to a high temperature by the compressor 34, is liquefied in the liquid-cooled condenser 78 by the fluid circulating in the heating circuit 32. At this time, the circulating liquid in the heating circuit 32 is heated by the high-temperature refrigerant to become a high-temperature liquid. The refrigerant in the refrigeration cycle circuit 30, after liquefaction in the liquid-cooled condenser 78, expands through the heating expansion valve 92 and vaporizes in the outdoor condenser 36, absorbing heat from the external gas. In other words, the outdoor condenser 36 functions as an evaporator at this time. The vaporized refrigerant returns to the compressor 34 through the first bypass flow path 94. The high-temperature liquid heated by the liquid-cooled condenser 78 is supplied to the heater core 44 by the heating circuit pump 104. The high-temperature liquid from the electric heater 38 can be supplied to either or both of the front and rear heater cores 44F and 44R via occupant operation. During this heat pump operation, the passenger compartment 20 is heated by heat drawn from the external gas.

[0054] Figure 8This diagram illustrates the operating state of the thermal management system 12 in the refrigeration zone C. In the following description, unless otherwise specified, the front evaporator 42F and the rear evaporator 42R are collectively referred to as evaporator 42. The refrigerant compressed by the compressor 34 releases heat relative to the outside gas in the outdoor condenser 36, thus being cooled and liquefied. The liquefied refrigerant expands through the electrically operated expansion valves 84 and 88, vaporizing and absorbing heat in the front and rear evaporators 42F and 42R, respectively. This cools the passenger compartment 20. Furthermore, when there are no passengers in the rear seats or when cooling of the rear side of the passenger compartment 20 is not required, the refrigerant supply to the rear evaporator 42R can be stopped by closing the solenoid valve 90.

[0055] Figure 9 This diagram illustrates the operating state of the thermal management system 12 in the parallel dehumidification and heating zone Dp. The refrigerant, compressed by the compressor 34, releases heat to the circulating liquid in the heating circuit 32 in the liquid-cooled condenser 78. As a result, a high-temperature liquid is generated in the heating circuit 32 and supplied to the heater core 44. Similar to the aforementioned heating operation, the high-temperature liquid can be supplied to either or both of the front heater core 44F and the rear heater core 44R. In parallel dehumidification and heating operation, the amount of heat movement achieved by the refrigeration cycle circuit 30 is less compared to the heating and cooling operations based on the heat pump, thus reducing the required capacity of the refrigeration cycle circuit 30. Consequently, the output of the compressor 34 is low, and the refrigerant, after releasing heat in the liquid-cooled condenser 78, is not completely liquefied but remains in a two-phase state of gas and liquid. A portion of the refrigerant goes to the outdoor condenser 36, where it vaporizes and absorbs heat at least partially through the reduced heating expansion valve 92. At this time, the outdoor condenser 36 functions as an evaporator. Refrigerant passing through the outdoor condenser 36 returns to the compressor 34 via the first bypass path 94. The remaining portion of the refrigerant passing through the liquid-cooled condenser 78 goes to the evaporator 42 via the second bypass path 96. In the evaporator 42, at least a portion of the liquid refrigerant vaporizes and absorbs heat. After passing through the evaporator 42, the refrigerant returns to the compressor 34. Furthermore, when there are no occupants in the rear seats or when cooling of the rear side of the passenger compartment 20 is not required, refrigerant supply to the rear evaporator 42R can be stopped by closing the solenoid valve 90.

[0056] In the air conditioning unit 28, water vapor is cooled and condensed in the evaporator 42, thus dehumidifying the air. By heating the cooled air in the heater core 44, the air conditioning unit 28 delivers warm and dry air to the passenger compartment 20.

[0057] Figure 10This diagram illustrates the operating state of the thermal management system 12 in the inline dehumidification and heating zone Ds. The refrigerant, compressed by the compressor 34, releases heat to the circulating liquid in the heating circuit 32 in the liquid-cooled condenser 78. As a result, high-temperature liquid is generated in the heating circuit 32 and supplied to the heater core 44. Similar to the aforementioned heating operation, high-temperature liquid can be supplied to either or both of the front heater core 44F and the rear heater core 44R. All the refrigerant passing through the liquid-cooled condenser 78 is transferred to the outdoor condenser 36. When the refrigerant releases a significant amount of heat in the liquid-cooled condenser 78, i.e., when heating is intensified, the refrigerant absorbs heat in the outdoor condenser 36, similar to the parallel dehumidification and heating operation. By reducing the opening of the heating expansion valve 92, a portion of the refrigerant vaporizes and absorbs heat in the outdoor condenser 36. On the other hand, when heating can be slightly weaker, the refrigerant releases heat in the outdoor condenser 36. In this case, the heating expansion valve 92 is fully open. In inline dehumidification and heating operation, the amount of heat movement achieved by the refrigeration cycle loop 30 is less compared to the heating and cooling operations based on a heat pump, thus reducing the required capacity of the refrigeration cycle loop 30. Consequently, the output of the compressor 34 is low, and the refrigerant, after releasing heat in the liquid-cooled condenser 78 and the outdoor condenser 36, is not completely liquefied, remaining in a two-phase gas-liquid state. The two-phase refrigerant proceeds to the evaporator 42. In the evaporator 42, the liquid phase of the refrigerant vaporizes and absorbs heat. After passing through the evaporator 42, the refrigerant returns to the compressor 34. Furthermore, when there are no occupants in the rear seats or when cooling of the rear side of the passenger compartment 20 is not required, the refrigerant supply to the rear evaporator 42R can be stopped by closing the solenoid valve 90.

[0058] In heating operation, the refrigeration cycle 30 moves outdoor heat into the passenger compartment 20 to heat the passenger compartment 20; in cooling operation, it moves heat from the passenger compartment 20 to the outside to cool the passenger compartment 20. In dehumidification and heating operation, the refrigeration cycle 30 absorbs heat from the evaporator 42 and releases heat from the heater core 44 via the heating circuit 32, thus moving heat within the passenger compartment 20. The difference between the heat absorbed by the evaporator 42 and the heat dissipated by the liquid-cooled condenser 78 is absorbed or dissipated by the outdoor condenser 36.

[0059] During dehumidification and heating operation, heat movement is less compared to heating and cooling operation, and the output of compressor 34 can be suppressed. Therefore, the refrigerant, after releasing heat, does not completely liquefy and remains in a gas-liquid two-phase state. When supplying the gas-liquid two-phase refrigerant to multiple objects, the distribution of the liquid phase refrigerant is sometimes uneven. When cooling the battery 18, it is necessary to reliably supply the liquid phase refrigerant to the battery cooling heat exchanger 41. In particular, when supplying refrigerant to both the front evaporator 42F and the rear evaporator 42R, and also to the battery cooling heat exchanger 41, it is sometimes impossible to adequately supply the liquid phase refrigerant.

[0060] In the dehumidification and heating zones Dp and Ds, when both the front and rear air conditioning units 28F and 28R are operating (dual mode), if there is a cooling requirement for the battery 18, the refrigeration cycle loop 30 operates in cooling mode, supplying liquid refrigerant to the evaporator 42 and supplying high-temperature liquid heated by the electric heater 38 to the heater core 44. During the cooling operation of the refrigeration cycle loop 30, the compressor 34 operates at high output, the refrigerant is fully compressed, and it is completely liquefied by releasing heat in the outdoor condenser 36. Thus, the required amount of liquid refrigerant is supplied to the front and rear evaporators 42F and 42R and the battery cooling heat exchanger 41.

[0061] If the temperature of battery 18 increases and the cooling requirement for battery 18 becomes more stringent, the output of compressor 34 will also increase. Consequently, the power required to drive compressor 34 increases, leading to higher power consumption. Increased power consumption results in a shorter driving range achieved by motor 16. In this thermal management system 12, when the cooling requirement for battery 18 increases and the battery's charge level is less than a predetermined value, for example, 20%, dehumidification of air conditioning unit 26 is stopped. Specifically, the supply of refrigerant to the front and rear evaporators 42F and 42R is stopped. By stopping the refrigerant supply to evaporators 42, the output of compressor 34 can be reduced, thus decreasing power consumption. Furthermore, since dehumidification is not performed, the temperature of the air passing through evaporators 42 does not decrease, and heating of heater core 44 can be reduced. Therefore, the power supplied to electric heater 38 can also be suppressed, further reducing power consumption. As a result, the decrease in the battery's charge level is suppressed, extending the driving range achieved by motor 16.

[0062] Figure 11 This diagram illustrates the operational status of the thermal management system 12, where the air conditioning unit 26 operates in dual modes in the dehumidification and heating zones Dp and Ds, and the battery cooling circuit 40 is in operation. In the refrigeration cycle circuit 30, the refrigerant compressed by the compressor 34 is supplied to the outdoor condenser 36, where it releases heat and completely liquefies. The liquid refrigerant is supplied to the front and rear evaporators 42F and 42R, and to the battery cooling heat exchanger 41. The refrigerant supplied to the front and rear evaporators 42F and 42R vaporizes here and absorbs heat from the air in the passenger compartment 20. The refrigerant supplied to the battery cooling heat exchanger 41 vaporizes here and absorbs heat from the battery coolant in the battery cooling circuit 40. Meanwhile, the battery coolant is cooled, and the cooled battery coolant is supplied to the battery 18 to cool the battery 18. In the heating circuit 32, the electric heater 38 operates to generate a high-temperature liquid, which is supplied to the heater core 44. If the coolant in engine 14 is sufficiently hot, the engine coolant can be supplied to the front and rear heater cores 44F and 44R.

[0063] Figure 12 This is a diagram illustrating the operating state of the thermal management system 12 in a situation where a need arises to cool the battery 18 more intensely. Relative to... Figure 11 In the operating state shown, the supply of refrigerant to the front and rear evaporators 42F and 42R is stopped. The high-temperature liquid in the heating circuit 32 is generated using the refrigerant compressed to a high temperature by the compressor 34. Since dehumidification is not performed in the air conditioning unit 28, the temperature of the air after passing through the evaporator 42 does not decrease, and reheating of the heater core 44 is unnecessary or only slightly required. If heating by the refrigerant in the refrigeration cycle circuit 30 is insufficient, heating of the circulating liquid in the heating circuit 32 is also performed in the electric heater 38.

[0064] Figure 13 This is a diagram illustrating the control flow of the thermal management system 12 when the front and rear air conditioning units 28F and 28R are both operating in dehumidification and heating mode, and when battery cooling is required. The control unit 60 controls the thermal management system 12 according to this control flow.

[0065] When the rear air conditioning switch 67 is on, meaning both the front and rear air conditioning units 28F and 28R are operating in dual mode (S100), and the operating condition is the dehumidification and heating zones Dp and Ds (S102), the control unit 60 further determines whether a battery cooling requirement exists (S104, S106). If the battery cooling requirement is higher than a first requirement value, the control unit 60 determines that battery cooling of the battery cooling circuit 40 is required (S104). The battery cooling requirement is determined, for example, based on the temperature of the battery 18 detected by the battery temperature sensor 100. If the battery cooling requirement is lower than the first requirement value in step S104, the process returns to the beginning of the control flow. If the battery cooling requirement is higher than the first requirement value, the control unit 60 further determines whether the battery cooling requirement is higher than a second requirement value (S106). The second requirement value corresponds to a requirement for stronger battery cooling than the first requirement value, for example, corresponding to a further increase in battery temperature. If the battery cooling requirement is lower than the second requirement value in step S106, then... Figure 11 As shown, the control unit 60 controls the refrigeration cycle circuit 30 to operate in a cooling mode, and controls the heating circuit 32 to operate in a heating mode (S108). The control unit 60 controls the refrigeration cycle circuit 30 to supply refrigerant to the battery cooling heat exchanger 41 of the battery cooling circuit 40, and the control unit 60 controls the battery cooling circuit 40 to supply coolant cooled by the refrigerant to the battery 18 (S108).

[0066] When refrigerant is supplied to three objects—the front and rear evaporators 42F and 42R, and the battery cooling heat exchanger 41—the refrigeration cycle loop 30 operates, enabling the refrigerant, which is only in the liquid phase, to be delivered to these three objects. Therefore, compared to the case where refrigerant is delivered in a two-phase (gas and liquid) state, refrigerant can be reliably supplied to all three objects.

[0067] If the battery cooling requirement in step S106 is higher than the second required value, the control unit 60 further determines whether the battery 18's charge level is lower than a specified value, for example, lower than 20% (S110). If the charge level is higher than the specified value, the process proceeds to step S108. If the charge level is lower than the specified value, the control unit 60 stops the dehumidification of the air conditioning device 26 (S112). Specifically, as... Figure 12 As shown, the control unit 60 controls the refrigeration cycle loop 30 by stopping the refrigerant supply to the front and rear evaporators 42F and 42R. The refrigeration cycle loop 30 supplies refrigerant only to the battery cooling heat exchanger 41. The heating circuit 32 supplies high-temperature liquid to the front and rear heater cores 44F and 44R as needed.

[0068] By stopping dehumidification, the increase in compressor 34 output can be suppressed, and the reheating of air in air conditioning unit 28 can be suppressed. As a result, the power consumption of battery 18 can be suppressed, and the driving range achieved by electric motor 16 can be extended.

[0069] Explanation of reference numerals in the attached figures

[0070] 10 Vehicle, 12 Thermal Management System, 14 Engine, 16 Electric Motor, 18 Battery, 20 Passenger Compartment, 22 Engine Radiator, 26 Air Conditioning Unit, 28 Air Conditioning Unit, 28F Front Air Conditioning Unit, 28R Rear Air Conditioning Unit, 30 Refrigeration Cycle Circuit, 32 Heating Circuit, 34 Compressor, 36 Outdoor Condenser, 38 Electric Heater, 40 Battery Cooling Circuit, 41 Battery Cooling Heat Exchanger, 42 Evaporator, 42F Front Evaporator, 42R Rear Evaporator, 44 Heater Core, 44F Front Heater Core, 44R Rear Heater Core, 60 Control Unit, 78 Liquid-Cooled Condenser, 84, 86 Electric Expansion Valves, 88 Expansion Valve, 90 Solenoid Valve, 92 Heating Expansion Valve, 94 First Bypass Flow Path, 96 Second Bypass Flow Path, 98 Battery Cooling Circuit Pump, 100 Battery Temperature Sensor, 102 Energy Storage Sensor, 104 Heating Circuit Pump, 106 Engine Cooling Circuit, 108 Three-Way Valve.

Claims

1. A thermal management system for a vehicle, comprising: The front air conditioning unit regulates the air in the front space of the vehicle's passenger compartment. The rear air conditioning unit is used to regulate the air in the rear space of the passenger compartment. The battery cooling circuit circulates coolant, which cools the battery that supplies power to the electric motor used to drive the vehicle. A refrigeration cycle circuit supplies refrigerant to the front air conditioning unit and the rear air conditioning unit, and also supplies refrigerant to a battery cooling heat exchanger that performs heat exchange between the coolant and the refrigerant in the battery cooling circuit; and The heating circuit uses a heat source or the refrigerant from the refrigeration cycle circuit to generate a high-temperature liquid, which is then supplied to the front air conditioning unit and the rear air conditioning unit. in, In the dehumidification and heating operation zone determined based on the control target of the air temperature delivered from the front air conditioning unit and the rear air conditioning unit, namely the required outlet temperature and the outside gas temperature, when the front air conditioning unit and the rear air conditioning unit are in operation and the cooling requirement of the battery is above the first required value, The refrigeration cycle operates in a cooling manner, supplying refrigerant to the front air conditioning unit, the rear air conditioning unit, and the battery cooling heat exchanger. The heating circuit utilizes the heat source to generate a high-temperature liquid. The battery cooling circuit uses coolant cooled by the refrigerant in the refrigeration cycle circuit in the battery cooling heat exchanger to cool the battery. If the cooling requirement of the battery is higher than the second requirement value and the battery's charge capacity is lower than the specified value, the supply of refrigerant from the refrigeration cycle to the front air conditioning unit and the rear air conditioning unit shall be stopped.

2. The vehicle thermal management system according to claim 1, The refrigeration cycle has a compressor that compresses the refrigerant and an outdoor heat exchanger that exchanges heat with the external gas. During the refrigeration operation, all the refrigerant compressed and sprayed by the compressor passes through the outdoor heat exchanger and is liquefied.

3. The vehicle thermal management system according to claim 1, The heat source of the heating circuit is one or both of the vehicle's engine and the electric heater.

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