Vehicle thermal management system

Abstract

To surely supply a refrigerant in a liquid phase when a battery for supplying electric power to an electric motor for driving a vehicle is cooled by the refrigerant of a refrigeration cycle circuit of an air conditioner.SOLUTION: When front and rear air-conditioning units 28F, 28R are performing a dehumidifying and heating operation and a battery 18 is to be cooled, a refrigeration cycle circuit 30 performs a cooling operation to supply a refrigerant in a liquid phase to front and rear evaporators 42F, 42R and a battery-cooling heat-exchanger 41. A heating circuit 32 supplies a high-temperature liquid heated by an electric heater 38 to front and rear heater cores 44F, 44R. Air cooled by the front and rear evaporators 42F, 42R is warmed by the front and rear heater cores 44F, 44R and supplied to a passenger compartment 20. A battery cooling liquid cooled by the battery-cooling heat-exchanger 41 is sent to the battery 18 to cool the battery.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a thermal management system that performs air conditioning in a vehicle passenger compartment and temperature management of in-vehicle devices.

Background Art

[0002] Patent Document 1 below shows a vehicle equipped with a front air conditioning unit (2) that sends air with adjusted temperature and humidity to the space in front of the passenger compartment and a rear air conditioning unit (3) that sends air with adjusted temperature and humidity to the space in the rear. The front and rear air conditioning units (2, 3) each include a heater core (27, 48) and an evaporator (26, 47), and can perform air conditioning independently at the front and rear of the passenger compartment.

[0003] Also, a vehicle air conditioning device that performs dehumidifying and heating operation to warm air with a heater core while cooling and dehumidifying it with an evaporator in a predetermined region determined from the relationship between the outside air temperature and the blowing temperature from the air conditioning unit is known.

[0004] Note that the reference numerals in the 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 the present application. [[ID=z1]]

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When the refrigeration cycle circuit for the air conditioning unit cools the battery that supplies power to the electric motor driving the vehicle, supplying refrigerant to the front and rear air conditioning units, and then supplying refrigerant for battery cooling, may result in insufficient air conditioning and battery cooling. In particular, when the air conditioning system is operating in dehumidifying and heating mode, the refrigerant supplied to the evaporators of the front and rear air conditioning units and the heat exchangers for battery cooling may be in a gas-liquid two-phase state. As a result, it may not be possible to adequately control the flow rate of refrigerant supplied to each evaporator and heat exchanger for battery cooling, and the required air conditioning and battery cooling performance may not be achieved.

[0007] This invention provides dehumidification heating This invention provides a vehicle thermal management system capable of achieving the required air conditioning and battery cooling performance in the operating range. [Means for solving the problem]

[0008] The vehicle thermal management system according to the present invention comprises a front air conditioning unit that provides air conditioning to the front space of the passenger compartment of the vehicle, a rear air conditioning unit that provides air conditioning to the rear space of the passenger compartment, a battery cooling circuit that circulates coolant to cool a battery that supplies power to an electric motor for vehicle drive, and a refrigeration cycle circuit that supplies refrigerant to the front air conditioning unit and the rear air conditioning unit, and also supplies refrigerant to a heat exchanger for battery cooling that exchanges heat between the coolant and refrigerant in the battery cooling circuit. This refrigeration cycle circuit is capable of operating in both cooling mode, where the refrigerant supplied to the front air conditioning unit, rear air conditioning unit, and battery cooling heat exchanger is completely liquefied, and dehumidifying heating mode, where the refrigerant is in a two-phase gas-liquid state. The system includes a heating circuit that generates a high-temperature liquid using a heat source or refrigerant from a refrigeration cycle circuit and supplies the high-temperature liquid to the front air conditioning unit and the rear air conditioning unit. The dehumidifying and heating operation range is defined by the required discharge temperature, which is the control target temperature of the air delivered from the front air conditioning unit and the rear air conditioning unit, and the outside temperature. In the dehumidifying heating operation range, the refrigeration cycle circuit normally performs dehumidifying heating operation.In the dehumidifying and heating operation range, if the front and rear air conditioning units are operating and the battery cooling requirement is greater than or equal to the first requirement value, the refrigeration cycle circuit operates in cooling mode and supplies refrigerant to the front and rear air conditioning units and the heat exchanger for battery cooling. The heating circuit generates a high-temperature liquid using a heat source. Furthermore, the battery cooling circuit cools the battery with a coolant cooled by the refrigerant in the refrigeration cycle circuit in the heat exchanger for battery cooling.

[0009] By operating the refrigeration cycle circuit in cooling mode, only the liquid phase of the refrigerant is used. This allows the liquid phase refrigerant to be supplied to the front air conditioning unit, the rear air conditioning unit, and the heat exchanger for battery cooling.

[0010] In the thermal management system of the above-mentioned vehicle, if the battery cooling requirement is higher than the second requirement (which is higher than the first requirement) and the battery's charge level is lower than a predetermined value, the supply of refrigerant to the front and rear air conditioning units by the refrigeration cycle circuit can be stopped. By suppressing the power consumed by the refrigeration cycle circuit, the driving range using the electric motor can be extended.

[0011] In the thermal management system of the above-mentioned vehicle, the refrigeration cycle circuit may include a compressor that compresses the refrigerant and an outdoor heat exchanger that exchanges heat with the outside air. During cooling operation, the entire amount of refrigerant compressed and discharged by the compressor passes through the outdoor heat exchanger and liquefies.

[0012] In the thermal management system for the vehicle described above, the heat source of the heating circuit may be either the engine that drives the vehicle or an electric heater, or both. [Effects of the Invention]

[0013] In the dehumidifying and heating operation range, when both the front and rear air conditioning units are operating and battery cooling is also required, liquid-phase refrigerant can be supplied to the front and rear air conditioning units and the heat exchanger for battery cooling. Compared to supplying refrigerant in a gas-liquid two-phase state, the amount of refrigerant supplied to the front air conditioning unit, the rear air conditioning unit, and the heat exchanger for battery cooling can be appropriately adjusted. [Brief explanation of the drawing]

[0014] [Figure 1] This figure shows a schematic configuration of a vehicle equipped with the thermal management system of this embodiment. [Figure 2] This figure shows the front air conditioning unit and its control unit. [Figure 3] This diagram schematically shows the configuration of the thermal management system of this embodiment. [Figure 4] This diagram shows the conditions that define the operating mode of an air conditioning system. [Figure 5] This diagram shows the operating status of the thermal management system, and in particular, the state during heating operation using engine coolant. [Figure 6] This diagram shows the operating status of the thermal management system, and in particular, the state during heating operation using electric heaters. [Figure 7] This diagram shows the operating status of the thermal management system, and in particular, the state during heating operation using the heat pump in the refrigeration cycle circuit. [Figure 8] This diagram shows the operating status of the thermal management system, and specifically the state during cooling operation. [Figure 9] This diagram shows the operating status of the thermal management system, and in particular, the status during parallel dehumidification and heating operation. [Figure 10] This diagram shows the operating status of the thermal management system, and in particular, the status during series dehumidification heating operation. [Figure 11] This diagram shows the operating state of the thermal management system, and in particular, the state when the front and rear air conditioning units are operating and the battery is being cooled in the dehumidifying and heating area. [Figure 12] It is a diagram showing the operating state of the thermal management system, and particularly shows the state when the battery cooling requirement is strong and the battery's stored power is low in the dehumidifying and heating region. [Figure 13] It is a diagram showing a part of the control flow of the thermal management system.

Embodiments for Carrying out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the schematic configuration of the thermal management system 12 of the vehicle 10. The vehicle 10 is equipped with an engine 14 as a prime mover for driving the vehicle 10, and two electric motors 16F and 16R for driving 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 is charged with the power generated by the electric motors 16F and 16R during braking. The vehicle may be a vehicle equipped with one electric motor that drives only the front or rear wheels. Further, the vehicle may be a vehicle that does not have an engine and drives one or both of the front and rear wheels with an electric motor. Hereinafter, for simplicity, the electric motors 16F and 16R are simply referred to as the motor 16.

[0016] The thermal management system 12 cools the engine 14, the motor 16, and the battery 18, and further conditions the air in the passenger compartment 20. The cooling system of the engine 14 includes an engine radiator 22 that dissipates the heat generated by the engine through engine coolant. The engine coolant flows through a pipe connecting the engine 14 and the engine radiator 22 and circulates between the engine 14 and the engine radiator 22. In FIG. 1, the pipe connecting the engine 14 and the engine radiator 22 is omitted. The cooling system of the motor 16 includes a motor radiator 24 that dissipates the heat generated by the motor 16 through motor coolant. The motor coolant flows through a pipe connecting the motor 16 and the motor radiator 24 and circulates between the motor 16 and the motor radiator 24. In FIG. 1, the pipe connecting the motor 16 and the motor radiator 24 is omitted.

[0017] The thermal management system 12 includes an air conditioning system 26 for air conditioning the passenger compartment 20. The air conditioning system 26 has an air conditioning unit 28 that supplies air with adjusted temperature, humidity, etc., to the passenger compartment 20. The air conditioning unit 28 includes a front air conditioning unit 28F for air conditioning the space on the front passenger side of the passenger compartment 20, and a rear air conditioning unit 28R for air conditioning the space on the rear passenger side. The air conditioning system 26 includes a refrigeration cycle circuit 30 that supplies refrigerant to the air conditioning unit 28, and a heating circuit 32 that supplies heated liquid. The refrigeration cycle circuit 30 includes a compressor 34 that compresses the refrigerant, and an outdoor condenser 36 that cools the refrigerant compressed by the compressor 34 with outside air to liquefy it. 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 rotational speed of the electric motor. The heating circuit 32 includes an electric heater 38 as a heat source. The refrigeration cycle circuit 30 and the heating circuit 32, along with other cooling systems of the thermal management system 12, will be described in more detail later.

[0018] The thermal management system 12 further includes a battery cooling circuit 40 for cooling the battery 18. The battery cooling circuit 40 cools the battery 18 by supplying battery cooling liquid, which has been cooled by the refrigerant of the refrigeration cycle circuit 30 in a battery cooling heat exchanger 41, to the battery 18.

[0019] Figure 2 is a schematic diagram showing the configuration of the front air conditioning unit 28F. The front air conditioning unit 28F has a front evaporator 42F, which is one of the components of the refrigeration cycle circuit 30, and a front heater core 44F, which is one of the components of the heating circuit 32, and further has an air conditioning case 46 that houses the front evaporator 42F and the front heater core 44F. The air conditioning case 46 has an air inlet 48 for introducing air into the air conditioning case 46. The air inlet 48 includes an internal air inlet 48C for introducing air from inside the occupant compartment 20 and an external air inlet 48E for introducing air from outside the vehicle. The air conditioning case 46 also has an air outlet 50 for sending conditioned air toward a predetermined location. The air outlet 50 includes a head outlet 50H that delivers airflow toward the heads and surrounding areas of occupants seated in the front seats, a foot outlet 50F that delivers airflow toward the feet of front seat occupants, and a defroster outlet 50D that delivers airflow toward the interior surface of the windshield. The airflow delivered from the head outlet 50H passes through a duct in the instrument panel (not shown) and is blown out from multiple outlets formed in the instrument panel toward the heads and surrounding areas of front seat occupants in the occupant compartment 20. The airflow delivered from the foot outlet 50F is blown out either directly from the foot outlet 50F or through a duct in the instrument panel toward the feet of front seat occupants. Furthermore, the airflow delivered from the defroster outlet 50D passes through a duct in the instrument panel and is blown out from an outlet located opposite the lower edge of the windshield. The front air conditioning unit 28F has a blower 52 located upstream of the air conditioning case 46. The blower 52 generates an airflow from the air inlet 48 to the air outlet 50.

[0020] An internal / external air switching door 54 is positioned at the junction of the airflow path from the internal air inlet 48C and the airflow path from the external air inlet 48E. The internal / external air switching door 54 is rotatable between a position that closes the internal air inlet 48C and a position that closes the external air inlet 48E, and the mixing ratio of internal and external air is adjusted according to the rotation angle. An air mix door 56 is positioned between the front evaporator 42F and the front heater core 44F. The air mix door 56 rotates to adjust the amount of air that passes through the front evaporator 42F and the front heater core 44F. Corresponding to each air outlet 50, an outlet door 58 is provided to open and close the air outlet 50. Specifically, a head outlet door 58H is provided for the head outlet 50H, a foot outlet door 58F is provided for the foot outlet 50F, and a defroster outlet door 58D is provided for the defroster outlet 50D. The amount of air blown from each outlet 50 is adjusted by the degree to which each outlet door 58 is opened.

[0021] The airflow rate of the blower 52, the rotation angles of the internal / external air switching door 54 and the air mix door 56, and the opening degree of each outlet door 58 are controlled by the control unit 60. Based on the conditions set by the occupant and the environmental conditions, the control unit 60 controls the rotation angles of the internal / external air switching door 54 and the air mix door 56, the opening degree of each outlet door 58, and the airflow rate of the blower 52. The occupant sets the desired temperature using the temperature setting switch 62 and then sets the desired air outlet 50 using the outlet selection switch 64. The selection of the air outlet 50 can be done in several ways, including selecting one of the air outlets 50H, 50F, or 50D individually, or selecting an air outlet mode that blows air from both the head outlet 50H and the foot outlet 50F. Furthermore, the occupants can set the automatic air conditioning mode using the automatic air conditioning switch 66. In this case, the control unit 60 selects an air outlet 50 from which to blow air according to a predetermined program, based on the desired temperature and environmental conditions. The control unit 60 receives input such as the ambient temperature of the occupant compartment 20 detected by the ambient temperature sensor 68, the ambient temperature detected by the ambient temperature sensor 70, the liquid temperature of the heating circuit 32 detected by the liquid temperature sensor 72, and the amount of solar radiation entering the occupant compartment 20 detected by the solar radiation sensor 74. In addition, the control unit 60 receives input of the temperature of the air immediately after it passes through the front evaporator 42F (evaporator outlet temperature), which is detected by the evaporator outlet temperature sensor 76 located immediately after the front evaporator 42F.

[0022] The rear air conditioning unit 28R has a configuration almost identical to that of the front air conditioning unit 28F, and is not shown in the diagram. The rear air conditioning unit 28R has an air conditioning case that houses the rear evaporator 42R and the rear heater core 44R (see Figure 1), and the air conditioning case is provided with an air inlet and an air outlet. In the rear air conditioning unit 28R, the air inlet does not need to include an outside air inlet, and the air outlet does not need to include a defroster outlet. The rear air conditioning unit 28R, like the front air conditioning unit 28F, provides air to the heads of the rear seat occupants. and It is possible to send air-conditioned air to either the surrounding area or the area around the user's feet, or to both.

[0023] 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 operates the rear air conditioning unit 28R in addition to the front air conditioning unit 28F. The front air conditioning unit 28F and the rear air conditioning unit 28R can be set to temperature and selected to airflow mode independently.

[0024] The control unit 60 is a processing device that controls the air conditioning system 26 according to a predetermined program and operates to achieve the temperature and airflow mode desired by the occupants according to the above-mentioned temperature, solar radiation, etc.

[0025] Figure 3 is a schematic diagram showing the configuration of the thermal management system 12. Components already described are denoted by the same reference numerals. The refrigeration cycle circuit 30 includes the compressor 34 and outdoor condenser 36 already described. Furthermore Front and rear evaporators 42F, 42 RIn addition, the refrigeration cycle circuit 30 includes a liquid-cooled condenser 78 that exchanges heat with the heating circuit 32 and a battery cooling heat exchanger 41 that exchanges heat with the battery cooling circuit 40. In the refrigeration cycle circuit 30, electrically operated expansion valves 84 and 86, whose opening degree can be adjusted, 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, and even when their opening degree is at its smallest, a small amount of refrigerant is supplied to the front evaporator 42F and the battery cooling heat exchanger 41. On the other hand, the supply of refrigerant 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 has an adjustable opening degree and may be an electrically operated expansion valve. When the refrigeration cycle circuit 30 is in heating operation, the refrigerant expands by passing through the heating expansion valve 92, which has a reduced opening, and vaporizes in the outdoor condenser 36, absorbing heat. Therefore, in heating operation, the outdoor condenser 36 functions as an evaporator. When the refrigeration cycle circuit 30 is in cooling operation, the heating expansion valve 92 is fully open, allowing the refrigerant to simply pass through. The capacity of the refrigeration cycle circuit 30 is adjusted by adjusting the output of the compressor 34 and the opening of each expansion valve 84, 86, 88, and 92.

[0026] The refrigeration cycle circuit 30 has a first bypass channel 94 arranged in parallel with the front and rear evaporators 42F, 42R and the heat exchanger 41 for battery cooling. The refrigerant can bypass the front and rear evaporators 42F, 42R and the heat exchanger 41 for battery cooling by passing through the first bypass channel 94. The refrigeration cycle circuit 30 also has a second bypass channel 96 arranged in parallel with the outdoor condenser 36, and the refrigerant can bypass the outdoor condenser 36 by passing through the second bypass channel 96.

[0027] 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 sending the coolant cooled by the battery cooling heat exchanger 41 to the battery 18. The battery 18 is equipped with a battery temperature sensor 100 that detects the temperature of the battery 18 and a charge level sensor 102 that detects the amount of charge stored in the battery 18. Based on the temperature of the battery 18, the level of cooling requirement for the battery 18 is determined, and the battery cooling circuit 40 is controlled according to the level. The charge level sensor 102 constantly monitors the power input and output to the battery 18 and calculates the current amount of charge by integrating the input and output power.

[0028] 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 that supplies high-temperature liquid. The heating circuit pump 104 circulates the circulating liquid through the electric heater 38, the front and rear heater cores 44F and 44R, and the liquid-cooled condenser 78. The liquid-cooled condenser 78 heats the circulating liquid in the heating circuit 32 with high-temperature refrigerant compressed by the compressor 34 of the refrigeration cycle circuit 30 to generate high-temperature liquid. The high-temperature liquid, which is the circulating liquid heated by the electric heater 38 or the liquid-cooled condenser 78, is sent to the front and rear heater cores 44F and 44R. The heating circuit 32 also shares heating / cooling liquid with the engine cooling circuit 106 and can utilize the engine 14 as a heat source. Whether the high-temperature liquid supplied to the front and rear heater cores 44F and 44R is supplied from the engine 14 side or from the electric heater 38 and liquid-cooled condenser 78 side is determined by the operation of the three-way valve 108.

[0029] The engine cooling circuit 106 includes the engine 14 and the engine radiator 22, and further 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 passage 112 arranged in parallel with the engine radiator 22, allowing the engine coolant to circulate by bypassing the engine radiator 22. When the engine 14 is cold, such as during warm-up, the engine cooling circuit 106 can quickly raise the temperature of the engine coolant by circulating it through the radiator bypass passage 112 instead of sending it to the engine radiator 22. As mentioned above, the engine coolant can be shared with the fluid in the heating circuit 32.

[0030] 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 are changed according to predetermined conditions. The changes in the flow paths of the refrigerant or fluid are achieved by the operation of multiple valves (not shown) appropriately provided in each circuit, in addition to the three-way valve 108 and solenoid valve 90 already described. The opening and closing and degree of opening of these valves may be controlled by the control unit 60. The control unit 60 also 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 needed.

[0031] The thermal management system 12 operates in several operating modes according to predetermined conditions. These predetermined conditions are determined, for example, based on the outside temperature, the temperature of the airflow blown out from the air conditioning unit 26 based on the occupant's requirements (required discharge temperature), and the cooling requirements and stored amount of the battery 18.

[0032] Figure 4 shows an example of the conditions that define the operating modes of the thermal management system 12, particularly the operating modes of the air conditioning system 26. In the heating region H, where the outside temperature is below a predetermined temperature T1 (e.g., 0°C), the thermal management system 12 operates in heating mode, i.e., performs heating operation. In the cooling region C, where the outside temperature is higher than the predetermined temperature T1, the required discharge temperature is low, and the difference between the required discharge temperature and the outside temperature is large, the thermal management system 12 operates in cooling mode, i.e., performs cooling operation. In the intermediate dehumidifying heating regions Dp and Ds between the heating region H and the cooling region C, the thermal management system 12 operates in dehumidifying heating mode, where the air taken in by the air conditioning unit 28 is first cooled and dehumidified, and then heated to the required discharge temperature, i.e., performs dehumidifying heating operation. The dehumidifying heating region is further divided into a parallel dehumidifying heating region Dp and a series dehumidifying heating region Ds. The thermal management system 12 performs parallel dehumidifying heating operation in the parallel dehumidifying heating region Dp and series dehumidifying heating operation in the series dehumidifying heating region Ds. Parallel dehumidification and heating operation is an operating mode in a range where heating is stronger compared to series dehumidification and heating operation. Furthermore, if the front air conditioning unit 28F and the rear air conditioning unit 28R can independently set their required discharge temperatures, the required discharge temperature of one of the predetermined air conditioning units 28, for example, the front air conditioning unit 28F, may be used as an element to define the operating mode. Alternatively, the required discharge temperature of the air conditioning unit 28 set to a lower temperature may be used as an element to define the operating mode. The operation of the thermal management system 12 in each operating mode will be described below.

[0033] Figures 5-7 show the operating state of the thermal management system 12 in the heating region H. In the following description, unless otherwise specified, the front heater core 44F and the rear heater core 44R will be collectively referred to as heater core 44.

[0034] Figure 5 shows the operating state when the engine coolant temperature of the engine 14 is sufficiently high. When the engine coolant temperature is high, a portion of the engine coolant circulating by the engine cooling circuit pump 110 is supplied to the heater core 44. The engine coolant may be supplied to either the front or rear heater cores 44F, 44R, or both, by operation by the occupant.

[0035] Figure 6 shows the operating state when the engine coolant temperature is low. When the engine coolant temperature is low, the electric heater 38 generates high-temperature fluid, which is supplied to the heater core 44 by the heating circuit pump 104. The occupant can operate the system to supply high-temperature fluid from the electric heater 38 to either or both of the front and rear heater cores 44F and 44R. In addition, for vehicles that do not have an engine 14 and run solely on the power of the electric motor 16, heating is provided by the electric heater 38 or by the heat pump operation of the refrigeration cycle circuit 30 described below.

[0036] Figure 7 shows the operating state when the refrigeration cycle circuit 30 is operated by a heat pump to provide heating. The refrigerant, which has been compressed to a high temperature by the compressor 34, is cooled and liquefied in the liquid-cooled condenser 78 by the fluid circulating in the heating circuit 32. At this time, the circulating fluid in the heating circuit 32 is heated by the high-temperature refrigerant and becomes a high-temperature liquid. The refrigerant of the refrigeration cycle circuit 30 that has been liquefied in the liquid-cooled condenser 78 expands as it passes through the heating expansion valve 92 and vaporizes in the outdoor condenser 36, absorbing heat from the outside air. In other words, at this time the outdoor condenser 36 functions as an evaporator. The vaporized refrigerant returns to the compressor 34 through the first bypass passage 94. The high-temperature liquid heated in 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 may be supplied to either or both of the front and rear heater cores 44F, 44R by operation by the occupant. In this heat pump operation, the crew compartment 20 is heated by heat drawn from the outside air.

[0037] Figure 8 shows the operating state of the thermal management system 12 in the cooling region C. In the following description, unless otherwise specified, the front evaporator 42F and the rear evaporator 42R will be collectively referred to as evaporator 42. The refrigerant compressed by the compressor 34 dissipates heat to the outside air in the outdoor condenser 36, cooling itself and liquefying. The liquefied refrigerant expands as it passes through the electric expansion valve 84 and expansion valve 88, and vaporizes and absorbs heat in the front and rear evaporators 42F and 42R, respectively. This cools the passenger compartment 20. Furthermore, when there is no need to cool the rear of the passenger compartment 20, such as when there are no passengers in the rear seats, the solenoid valve 90 may be closed to prevent the refrigerant from being supplied to the rear evaporator 42R.

[0038] Figure 9 shows the operating state of the thermal management system 12 in the parallel dehumidification heating region Dp. The refrigerant compressed by the compressor 34 releases heat to the circulating liquid in the heating circuit 32 via the liquid-cooled condenser 78. This generates high-temperature liquid in the heating circuit 32, which is supplied to the heater core 44. Similar to the heating operation described above, the high-temperature liquid may be supplied to either or both of the front heater core 44F and the rear heater core 44R. In parallel dehumidification heating operation, the amount of heat transferred by the refrigeration cycle circuit 30 is less than in heating and cooling operations using a heat pump, so the capacity required of the refrigeration cycle circuit 30 is smaller. Therefore, the output of the compressor 34 is low, and the refrigerant that releases heat in the liquid-cooled condenser 78 does not completely liquefy, remaining in a two-phase gas-liquid state. A portion of the refrigerant heads toward the outdoor condenser 36, passes through the restricted heating expansion valve 92, and at least a portion of it vaporizes in the outdoor condenser 36, absorbing heat. At this time, the outdoor condenser 36 functions as an evaporator. The refrigerant that has passed through the outdoor condenser 36 returns to the compressor 34 via the first bypass passage 94. The remaining refrigerant that has passed through the liquid-cooled condenser 78 goes to the evaporator 42 via the second bypass passage 96. At least a portion of the liquid-phase refrigerant vaporizes in the evaporator 42, absorbing heat. After passing through the evaporator 42, the refrigerant returns to the compressor 34. In addition, when there is no need to cool the rear of the passenger compartment 20, such as when there are no passengers in the rear seats, the solenoid valve 90 may be closed to prevent the refrigerant from being supplied to the rear evaporator 42R.

[0039] In the air conditioning unit 28, the evaporator 42 cools the air, causing water vapor to cool and condense, thus dehumidifying it. By heating the cooled air in the heater core 44, the air conditioning unit 28 sends warm, dry air to the crew compartment 20.

[0040] Figure 10 shows the operating state of the thermal management system 12 in the series dehumidification heating region Ds. The refrigerant compressed by the compressor 34 is released into the circulating liquid of the heating circuit 32 by the liquid-cooled condenser 78. This generates high-temperature liquid in the heating circuit 32, which is supplied to the heater core 44. As with the heating operation described above, the high-temperature liquid may be supplied to either or both of the front heater core 44F and the rear heater core 44R. The entire amount of refrigerant that has passed through the liquid-cooled condenser 78 is sent to the outdoor condenser 36. In the outdoor condenser 36, when a large amount of heat is released by the refrigerant in the liquid-cooled condenser 78, that is, when heating is increased, the refrigerant absorbs heat, similar to the parallel dehumidification heating operation. By narrowing 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 is not required, the refrigerant releases heat in the outdoor condenser 36. In this case, the heating expansion valve 92 is fully open. In series dehumidifying heating operation, the amount of heat transferred by the refrigeration cycle circuit 30 is less than in heating and cooling operations using a heat pump, so the required capacity of the refrigeration cycle circuit 30 is reduced. As a result, the output of the compressor 34 is low, and the refrigerant that has dissipated heat in the liquid-cooled condenser 78 and the outdoor condenser 36 does not completely liquefy, remaining in a two-phase gas-liquid state. The gas-liquid two-phase refrigerant moves towards the evaporator 42. In the evaporator 42, the liquid phase refrigerant vaporizes and absorbs heat. After passing through the evaporator 42, the refrigerant returns to the compressor 34. Also, when there are no passengers in the rear seats, or when there is no need to cool the rear of the passenger compartment 20, the solenoid valve 90 can be closed to prevent the refrigerant from being supplied to the rear evaporator 42R.

[0041] The refrigeration cycle circuit 30 heats the occupant compartment 20 by transferring heat from the outside during heating operation, and cools the occupant compartment 20 by transferring heat from the occupant compartment 20 to the outside during cooling operation. In dehumidifying heating operation, the refrigeration cycle circuit 30 absorbs heat from the evaporator 42 and releases heat from the heater core 44 via the heating circuit 32, transferring heat within the occupant compartment 20. The difference between the amount of heat absorbed by the evaporator 42 and the amount of heat released by the liquid-cooled condenser 78 is absorbed or released by the outdoor condenser 36.

[0042] In dehumidifying heating operation, less heat is transferred compared to heating and cooling operation, and the output of the compressor 34 is also reduced. As a result, the refrigerant does not completely liquefy after heat dissipation, remaining in a gas-liquid two-phase state. When supplying a gas-liquid two-phase refrigerant to multiple targets, the distribution of the liquid phase refrigerant may be 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 may not be possible to supply enough liquid phase refrigerant.

[0043] Thermal Management System 12 In In the dehumidifying 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 request for the battery 18, the refrigeration cycle circuit 30 operates in cooling mode and supplies liquid-phase refrigerant to the evaporator 42, and high-temperature liquid heated by the electric heater 38 is supplied to the heater core 44. During the cooling operation of the refrigeration cycle circuit 30, the compressor 34 operates at high output, the refrigerant is sufficiently compressed, and by dissipating heat in the outdoor condenser 36, it is completely liquefied. As a result, the required amount of liquid-phase refrigerant is supplied to the front and rear evaporators 42F and 42R, as well as the heat exchanger 41 for battery cooling.

[0044] If the temperature of the battery 18 rises, or if the cooling requirement for the battery 18 increases further, the output of the compressor 34 will also increase accordingly. Therefore, the power required to drive the compressor 34 will also increase, resulting in higher power consumption. Higher power consumption will shorten the driving range of the electric motor 16. In this thermal management system 12, when the cooling requirement for the battery 18 increases and the amount of charge stored in the battery 18 is less than a predetermined value, for example, 20%, dehumidification by the air conditioning system 26 is stopped. Specifically, the supply of refrigerant to the front and rear evaporators 42F and 42R is stopped. By stopping the supply of refrigerant to the evaporator 42, the output of the compressor 34 can be reduced, thereby reducing power consumption. Also, since dehumidification is not performed, the temperature of the air after passing through the evaporator 42 does not decrease, and less heating by the heater core 44 is required. Therefore, the power supplied to the electric heater 38 can also be suppressed, resulting in lower power consumption. As a result, the decrease in the amount of charge stored in the battery 18 is suppressed, and the driving range using the electric motor 16 can be extended.

[0045] Figure 11 shows the operating state of the thermal management system 12 in which the air conditioning unit 26 operates in dual mode and the battery cooling circuit 40 operates in the dehumidifying heating regions Dp and Ds. In the refrigeration cycle circuit 30, the refrigerant compressed by the compressor 34 is sent to the outdoor condenser 36, where it dissipates heat and is completely liquefied. The liquid phase refrigerant is supplied to the front and rear evaporators 42F and 42R and the heat exchanger 41 for battery cooling. The refrigerant sent to the front and rear evaporators 42F and 42R vaporizes here and absorbs heat from the air in the occupant compartment 20. The refrigerant sent to the heat exchanger 41 for battery cooling 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 sent to the battery 18 to cool the battery 18. In the heating circuit 32, the electric heater 38 operates to generate high-temperature liquid, which is supplied to the heater core 44. If the coolant of the engine 14 is at a sufficiently high temperature, the engine coolant may be supplied to the front and rear heater cores 44F and 44R.

[0046] Figure 12 shows the operating state of the thermal management system 12 when it becomes necessary to cool the battery 18 more strongly. Compared to the operating state shown in Figure 11, the supply of refrigerant to the front and rear evaporators 42F and 42R is stopped. The refrigerant, which has been compressed and heated to a high temperature by the compressor 34, generates the high-temperature liquid in the heating circuit 32. 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 by the heater core 44 is unnecessary or only required minimally. If heating by the refrigerant in the refrigeration cycle circuit 30 is insufficient, the electric heater 38 also heats the circulating liquid in the heating circuit 32.

[0047] Figure 13 shows the control flow of the thermal management system 12 when both the front and rear air conditioning units 28F and 28R are performing dehumidifying and heating operation, and there is also a request for battery cooling. The control unit 60 controls the thermal management system 12 according to this control flow.

[0048] 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 conditions are in the dehumidifying heating area Dp and Ds (S102), the control unit 60 further determines whether there is a request for battery cooling (S104, S106). If the battery cooling request is equal to or greater than the first request value, the control unit 60 determines that battery cooling by the battery cooling circuit 40 is necessary (S104). The battery cooling request is determined based on the temperature of the battery 18 detected, for example, by the battery temperature sensor 100. In step S104, if the battery cooling request is less than the first request value, the process returns to the start of this control flow. If the battery cooling request is equal to or greater than the first request value, the control unit 60 further determines whether the battery cooling request is equal to or greater than the second request value (S106). The second requirement corresponds to a stronger battery cooling requirement than the first requirement, for example, when the battery temperature rises further. In step S106, if the battery cooling requirement is less than the second requirement, the control unit 60 controls the refrigeration cycle circuit 30 to operate in cooling mode and the heating circuit 32 to operate in heating mode, as shown in Figure 11 (S108). The control unit 60 controls the refrigeration cycle circuit 30 to send refrigerant to the battery cooling heat exchanger 41 of the battery cooling circuit 40, and further controls the battery cooling circuit 40 to send the coolant cooled by this refrigerant to the battery 18 (S108).

[0049] In a situation where refrigerant is supplied to three targets—the front and rear evaporators 42F and 42R and the heat exchanger 41 for battery cooling—the refrigeration cycle circuit 30 can deliver only liquid-phase refrigerant to the three targets by operating in cooling mode. This ensures a more reliable supply of refrigerant to the three targets compared to the case where gas-liquid two-phase refrigerant is supplied.

[0050] If the battery cooling requirement in step S106 is greater than or equal to the second requirement value, the control unit 60 further determines whether the charge level of the battery 18 is less than a predetermined value, for example, less than 20% (S110). If the charge level is greater than or equal to the predetermined value, the process proceeds to step S108. If the charge level is less than the predetermined value, the control unit 60 stops the dehumidification of the air conditioner 26 (S112). Specifically, as shown in Figure 12, the control unit 60 controls the refrigeration cycle circuit 30 to stop supplying refrigerant to the front and rear evaporators 42F and 42R. The refrigeration cycle circuit 30 supplies refrigerant only to the heat exchanger 41 for battery cooling. The heating circuit 32 supplies high-temperature liquid to the front and rear heater cores 44F and 44R as needed.

[0051] By stopping dehumidification, the increase in output of the compressor 34 can be suppressed, and the reheating of the air in the air conditioning unit 28 can be suppressed. This reduces the power consumption of the battery 18 and extends the driving range of the electric motor 16. [Explanation of Symbols]

[0052] 10 Vehicle, 12 Thermal Management System, 14 Engine, 16 Electric Motor, 18 Battery, 20 Crew Compartment, 22 Engine Radiator, 26 Air Conditioning System, 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 Heat Exchanger for Battery Cooling, 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 Valve, 88 Expansion Valve, 90 Solenoid Valve, 92 Heating Expansion Valve, 94 First Bypass Flow Channel, 96 Second Bypass Flow Channel, 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 front air conditioning unit that provides air conditioning for the front space of the passenger compartment of a vehicle, A rear air conditioning unit that provides air conditioning for the space behind the passenger compartment, A battery cooling circuit that circulates a coolant to cool the battery that supplies power to the electric motor used to drive the vehicle, A refrigeration cycle circuit that supplies refrigerant to the front air conditioning unit and the rear air conditioning unit, and also supplies refrigerant to a heat exchanger for battery cooling that exchanges heat between the coolant and refrigerant in the battery cooling circuit, the refrigeration cycle circuit capable of operating in a cooling operation in which the refrigerant supplied to the front air conditioning unit, the rear air conditioning unit and the heat exchanger for battery cooling is completely liquefied, and a dehumidifying heating operation in which the refrigerant is in a gas-liquid two-phase state, A heating circuit that generates a high-temperature liquid using a heat source or the refrigerant of the refrigeration cycle circuit and supplies the high-temperature liquid to the front air conditioning unit and the rear air conditioning unit, A thermal management system for a vehicle equipped with, In the dehumidifying heating operation range in which the refrigeration cycle circuit performs the dehumidifying heating operation, which is determined based on the desired discharge temperature, which is the control target for the temperature of the air discharged from the front air conditioning unit and the rear air conditioning unit, and the outside temperature, if the front air conditioning unit and the rear air conditioning unit are operating and the cooling requirement of the battery is equal to or greater than the first required value, The refrigeration cycle circuit performs the cooling operation and supplies refrigerant to the front air conditioning unit, the rear air conditioning unit, and the heat exchanger for battery cooling. The heating circuit generates a high-temperature liquid using the heat source, The battery cooling circuit cools the battery using a coolant cooled by the refrigerant of the refrigeration cycle circuit in the heat exchanger for battery cooling. Vehicle thermal management system.

2. A vehicle thermal management system according to claim 1, wherein when the cooling requirement of the battery is greater than or equal to a second requirement value which is higher than the first requirement value, and the amount of charge stored in the battery is lower than a predetermined value, the supply of refrigerant by the refrigeration cycle circuit to the front air conditioning unit and the rear air conditioning unit is stopped.

3. A vehicle thermal management system according to claim 1 or 2, wherein the refrigeration cycle circuit comprises a compressor for compressing a refrigerant and an outdoor heat exchanger for exchanging heat with outside air, and during cooling operation, the entire amount of refrigerant compressed and discharged by the compressor passes through the outdoor heat exchanger and is liquefied.

4. A vehicle thermal management system according to claim 1 or 2, wherein the heat source of the heating circuit is either or both of the engine that drives the vehicle and / or an electric heater.

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