Refrigeration cycle device

Abstract

Comprises: a circuit switching section (38) that switches a heat medium circuit (30) to a first circulation state in which a heat medium circulates between a power transmission device (35, 36) and a radiator (32), or to a second circulation state in which the heat medium circulates between the power transmission device and a cooler (17); a loop switching determination unit (60f) that determines to switch to the second cycle state by the loop switching unit when it is determined that the temperature of the power transmission device exceeds a threshold value (PT) in the first cycle state; a cooling switching unit (16) that switches between a cooler cooling state in which the heat medium is cooled by the cooler and a cooler non-cooling state in which the heat medium is not cooled by the cooler; and a cooler cooling determination unit (60c) that determines a cooler cooling start time, which is a time at which the cooling switching unit switches from the cooler non-cooling state to the cooler cooling state, on the basis of travel state-related information, which is information related to the travel state of the vehicle.

Description

Citation of related applications

[0001] This application is based on Japanese Patent Application No. 2023-32908 filed on March 3, 2023, and the contents thereof are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to a refrigeration cycle device for cooling power transmission equipment. Background Art

[0003] Patent Document 1 describes a vehicle refrigeration cycle device that recovers heat from powertrain equipment such as inverters and motor generators and uses it to heat the vehicle interior. Powertrain equipment is electrical equipment that generates driving force for the vehicle and generates heat during operation.

[0004] In this prior art, a cooling water cooling evaporator, a low-temperature side radiator, and a power transmission device are arranged in parallel within the low-temperature cooling water circuit. The cooling water cooling evaporator exchanges heat between the low-pressure refrigerant in the refrigeration cycle and the low-temperature cooling water in the low-temperature cooling water circuit, allowing the low-pressure refrigerant to absorb heat from the low-temperature cooling water. The low-temperature side radiator transfers heat from the low-temperature cooling water to the outside air.

[0005] In this conventional technology, the three-way valve can switch between a state in which low-temperature cooling water circulates between the power transmission device and the cooling water cooling evaporator and a state in which low-temperature cooling water circulates between the power transmission device and the low-temperature side radiator.

[0006] When low-temperature cooling water is circulated between the powertrain and the cooling water cooling evaporator, heat dissipated from the powertrain is used for heating the vehicle interior. When low-temperature cooling water is circulated between the powertrain and the low-temperature side radiator, heat dissipated from the powertrain is dissipated to the outside air. Prior art literature Patent Literature

[0007] Patent Document 1: Japanese Patent No. 6791052 Summary of the Invention

[0008] In the above-mentioned prior art, efficient cooling of the power transmission device is not considered, and therefore there are limitations in miniaturization of the power transmission device or improvement of driving performance.

[0009] In view of the above problems, the present disclosure aims to efficiently cool a power transmission device.

[0010] A refrigeration cycle device according to one embodiment of the present disclosure includes a heat medium circuit, a power transmission device, a radiator, a cooler, a circuit switcher, a circuit switch determination unit, a cooling switcher, and a cooler cooling determination unit.

[0011] The heat medium circulates in the heat medium circuit. The powertrain, an electrical device used to generate the vehicle's driving force, is cooled by the heat medium. The radiator exchanges heat between the heat medium and the outside air. The cooler exchanges heat between the low-pressure refrigerant in the refrigeration cycle and the heat medium.

[0012] The circuit switching unit switches the heat medium circuit between a first circulation state in which the heat medium circulates between the power transmission device and the radiator and a second circulation state in which the heat medium circulates between the power transmission device and the cooler.

[0013] The circuit switching determination unit determines that the temperature of the power transmission device exceeds a threshold value in the first circulation state, and determines to switch to the second circulation state via the circuit switching unit. The cooling switching unit switches between a cooler cooling state in which the heat medium is cooled by the cooler and a cooler non-cooling state in which the heat medium is not cooled by the cooler.

[0014] The cooler cooling determination unit determines a cooler cooling start time when the cooling switch unit switches from the cooler non-cooling state to the cooler cooling state based on information about the vehicle's driving state, that is, driving state related information.

[0015] Thus, the power transmission device can be cooled based on the information related to the driving state, and thus the power transmission device can be cooled efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above-mentioned objects, other objects, features and advantages of the present disclosure will become more apparent with reference to the accompanying drawings and the following detailed description. Figure 1 It is a diagram showing the overall configuration of the refrigeration cycle device according to the first embodiment. Figure 2 This is a block diagram showing an electrical control unit of the refrigeration cycle device according to the first embodiment. Figure 3 This is a configuration diagram showing a low-temperature cooling water circuit in a radiator heat radiation mode of the refrigeration cycle device according to the first embodiment. Figure 4 This is a structural diagram showing a low-temperature cooling water circuit in the radiator heat radiation mode and the cooler ON mode of the refrigeration cycle device according to the first embodiment. Figure 5 This is a configuration diagram showing a low-temperature cooling water circuit in a cooler cooling mode of the refrigeration cycle device according to the first embodiment. Figure 6 This is a flowchart showing a part of the control process executed by the control device of the refrigeration cycle device according to the first embodiment. Figure 7This is a flowchart showing a part of the control process executed by the control device of the refrigeration cycle device according to the first embodiment. Figure 8 This is a timing chart showing a control example in the refrigeration cycle device according to the first embodiment. Figure 9 This is a flowchart showing a part of the control process executed by the control device of the refrigeration cycle device according to the second embodiment. Figure 10 This is a flowchart showing a part of the control process executed by the control device of the refrigeration cycle device according to the third embodiment. Figure 11 It is a timing chart showing a control example in the refrigeration cycle device according to the third embodiment. Figure 12 This is a flowchart showing a part of the control process executed by the control device of the refrigeration cycle device according to the fourth embodiment. Figure 13 It is a timing chart showing a control example in the refrigeration cycle device according to the fourth embodiment. Figure 14 This is a flowchart showing a part of the control process executed by the control device of the refrigeration cycle device according to the fifth embodiment. Figure 15 1 is a control characteristic diagram showing a control example in the refrigeration cycle device according to the fifth embodiment. Figure 16 It is a diagram showing the overall configuration of a refrigeration cycle device according to the sixth embodiment. DETAILED DESCRIPTION

[0017] Hereinafter, with reference to the accompanying drawings, a plurality of methods for implementing the present disclosure will be described. In each embodiment, the same reference numerals are sometimes used to mark portions corresponding to matters described in a previous embodiment, and repeated descriptions are omitted. In the case where only a portion of a structure is described in each embodiment, other embodiments previously described can be applied to other portions of the structure. Not only are combinations of parts that can be combined specifically and clearly described in each embodiment, but as long as there is no hindrance to the combination, partial combinations between the embodiments may be made even without explicit description.

[0018] (First embodiment) Hereinafter, embodiments will be described based on the drawings. Figure 1 The refrigeration cycle device 10 shown is suitable for use in a vehicle air conditioning system 1 installed in an electric vehicle or hybrid vehicle. An electric vehicle is a vehicle that obtains its driving force from an electric motor. A hybrid vehicle is a vehicle that obtains its driving force from an engine (in other words, an internal combustion engine) and a driving electric motor.

[0019] Vehicle air conditioner 1 is an air conditioner with a battery temperature control function. Vehicle air conditioner 1 performs air conditioning in the vehicle interior, the air conditioning target space, and also regulates the temperatures of battery 33, inverter 35, and motor generator 36. Therefore, the objects to be cooled in refrigeration cycle device 10 of this embodiment are air, battery 33, inverter 35, and motor generator 36.

[0020] The battery 33 is a secondary battery that stores power to be supplied to onboard devices such as the motor. In this embodiment, the battery 33 is a lithium-ion battery. The battery 33 is a so-called battery pack formed by stacking a plurality of battery cells (not shown) and electrically connecting these battery cells in series or in parallel.

[0021] Inverter 35 is a power conversion unit that converts DC power supplied from battery 33 into AC power and outputs it to motor generator 36. Motor generator 36 uses the power output from inverter 35 to generate driving force for running and regenerates power during deceleration or downhill driving.

[0022] The inverter 35 and the motor generator 36 are electrical devices (so-called power transmission devices) for generating driving force for the vehicle, and generate heat during operation.

[0023] The object to be cooled in refrigeration cycle device 10 may also be a power transmission device such as a DC-DC converter or a charger. The DC-DC converter converts the high-voltage DC power supplied by battery 33 into low-voltage DC power, which is then supplied to auxiliary equipment installed on the vehicle. The charger is used to charge battery 33 from an external power source.

[0024] In the vehicle air conditioner 1 , the battery 33 , the inverter 35 , and the motor generator 36 can be cooled by the cold heat generated by the refrigeration cycle device 10 .

[0025] The refrigeration cycle device 10 is a vapor compression refrigerator that includes a compressor 11, a condenser 12, a first expansion valve 13, a first evaporator 14, a constant pressure valve 15, a second expansion valve 16, a cooler 17, and a receiver 18. In this embodiment, the refrigeration cycle device 10 uses a Freon-based refrigerant as the refrigerant, forming a subcritical refrigeration cycle in which the high-pressure side refrigerant pressure does not exceed the critical pressure of the refrigerant. Refrigeration oil (specifically, PAG oil) is mixed with the refrigerant to lubricate the compressor 11. A portion of the refrigeration oil circulates through the circulation system along with the refrigerant.

[0026] The compressor 11 is an electric compressor driven by the electric power supplied by the battery 33, and sucks in the refrigerant of the refrigeration cycle device 10, compresses it, and discharges it. The compressor 11 may also be a variable capacity compressor driven by a belt.

[0027] The condenser 12 is a high-pressure-side refrigerant heat medium heat exchanger that condenses the high-pressure-side refrigerant by exchanging heat between the high-pressure-side refrigerant discharged from the compressor 11 and the cooling water in the high-temperature cooling water circuit 20 .

[0028] The cooling water in the high-temperature cooling water circuit 20 is a fluid serving as a heat medium. The cooling water in the high-temperature cooling water circuit 20 is a high-temperature heat medium. In this embodiment, a liquid containing at least ethylene glycol, dimethylpolysiloxane, or a nanofluid, or an antifreeze liquid, is used as the cooling water in the high-temperature cooling water circuit 20. The high-temperature cooling water circuit 20 is a high-temperature heat medium circuit in which the high-temperature heat medium circulates.

[0029] The receiver 18 is a gas-liquid separator that separates the refrigerant flowing out of the condenser 12 into gas and liquid, allowing the liquid refrigerant to flow downstream, and stores the remaining refrigerant in the cycle. The flow of the liquid refrigerant flowing out of the receiver 18 branches at the branching portion 10a.

[0030] The first expansion valve 13 is the first decompression unit that decompresses and expands the liquid-phase refrigerant flowing out of the receiver 18. The first expansion valve 13 is an electrically variable throttle mechanism comprising a valve element and an electric actuator. The valve element is configured to vary the opening of the refrigerant flow path (in other words, the throttle opening). The electric actuator includes a stepping motor that changes the throttle opening of the valve element.

[0031] The first expansion valve 13 is composed of a variable throttling mechanism, which has a fully closed function to completely close the flow path of the refrigerant. The operation of the first expansion valve 13 is Figure 2 The control device 60 shown outputs a control signal control.

[0032] The first evaporator 14 is a refrigerant-air heat exchanger. It exchanges heat between the refrigerant flowing out of the first expansion valve 13 and the air being blown into the vehicle interior, evaporating the refrigerant and cooling the air being blown into the vehicle interior. The first evaporator 14 is an air evaporator that evaporates the refrigerant and cools the air. The first evaporator 14 is a first evaporation unit.

[0033] The constant-pressure valve 15 is a pressure regulating unit (in other words, a pressure-reducing unit) that maintains the refrigerant pressure at the outlet of the first evaporator 14 within a specified range. By maintaining the refrigerant pressure (in other words, the refrigerant temperature) in the first evaporator 14 above a specified value, the constant-pressure valve 15 suppresses frost formation in the first evaporator 14.

[0034] The constant pressure valve 15 comprises a mechanical variable throttling mechanism. Specifically, when the refrigerant pressure at the outlet of the first evaporator 14 falls below a predetermined value, the constant pressure valve 15 reduces the refrigerant flow area (i.e., the throttling opening). When the refrigerant pressure at the outlet of the first evaporator 14 exceeds the predetermined value, the constant pressure valve 15 increases the refrigerant flow area (i.e., the throttling opening).

[0035] When the flow rate of the circulating refrigerant circulating in the circulation system does not fluctuate much, a fixed throttle portion formed of an orifice, a capillary tube, or the like may be used instead of the constant pressure valve 15 .

[0036] The second expansion valve 16 and the cooler 17 are arranged in parallel with the first expansion valve 13 , the first evaporator 14 , and the constant pressure valve 15 in the flow of the refrigerant.

[0037] The second expansion valve 16 is a second pressure reducing unit that reduces and expands the liquid-phase refrigerant flowing out of the condenser 12. It is an electrically variable throttling mechanism comprising a valve element and an electric actuator. The valve element is configured to vary the opening of the refrigerant flow path (in other words, the throttle opening). The electric actuator includes a stepping motor that changes the throttle opening of the valve element.

[0038] Second expansion valve 16 comprises a variable throttle mechanism with a fully closed function, completely closing the refrigerant flow path. In other words, second expansion valve 16 can shut off the flow of refrigerant by fully closing the refrigerant flow path. The operation of second expansion valve 16 is controlled by a control signal output by control device 60.

[0039] Cooler 17 is a second evaporator. It exchanges heat between the low-pressure refrigerant flowing out of the second expansion valve 16 and the cooling water in the low-temperature cooling water circuit 30, evaporating the refrigerant and cooling the cooling water. Cooler 17 is a low-pressure refrigerant-heat medium heat exchanger. Cooler 17 is a cooling evaporator that evaporates the refrigerant and cools the cooling water. Cooler 17 is a second evaporation unit.

[0040] The gas-phase refrigerant evaporated in the cooler 17 merges with the refrigerant flowing out of the constant pressure valve 15 at the merging portion 10 b , and is then sucked into the compressor 11 and compressed.

[0041] The cooling water in the low-temperature cooling water circuit 30 is a fluid serving as a heat medium. The cooling water in the low-temperature cooling water circuit 30 is a low-temperature heat medium. In this embodiment, a liquid containing at least ethylene glycol, dimethylpolysiloxane, or a nanofluid, or an antifreeze liquid, is used as the cooling water in the low-temperature cooling water circuit 30. The low-temperature cooling water circuit 30 is a low-temperature heat medium circuit in which a low-temperature heat medium circulates.

[0042] The high-temperature cooling water circuit 20 includes a condenser 12 , a high-temperature-side pump 21 , a heater core 22 , a high-temperature-side radiator 23 , an on-off valve 24 , and an electric heater 25 .

[0043] The high-temperature side pump 21 is a heat medium pump that draws in and discharges cooling water. The high-temperature side pump 21 is an electric pump. The high-temperature side pump 21 is a high-temperature side flow rate regulator that regulates the flow rate of cooling water circulating in the high-temperature cooling water circuit 20.

[0044] The heater core 22 is an air heating heat exchanger that heats the air being blown into the vehicle cabin by exchanging heat between the coolant in the high-temperature coolant circuit 20 and the air being blown into the vehicle cabin. In the heater core 22, the coolant dissipates heat to the air being blown into the vehicle cabin. The condenser 12, the high-temperature coolant circuit 20, and the heater core 22 form a heat dissipation unit that heats the refrigerant discharged from the compressor 11 by exchanging heat with the air being blown into the vehicle cabin.

[0045] The high-temperature side radiator 23 is a high-temperature heat medium outside air heat exchanger that exchanges heat between the coolant in the high-temperature coolant circuit 20 and the outside air. The high-temperature side radiator 23 and the on-off valve 24 are arranged in parallel with the heater core 22 in the flow of the high-temperature side coolant.

[0046] The on-off valve 24 is a solenoid valve that opens and closes the cooling water flow path on the high-temperature radiator 23 side. The operation of the on-off valve 24 is controlled by the control device 60. The on-off valve 24 is a high-temperature switching unit that switches the flow of cooling water in the high-temperature cooling water circuit 20.

[0047] The on-off valve 24 may also be a thermostat. A thermostat is a cooling water temperature-responsive valve comprising a mechanical mechanism that opens and closes the cooling water flow path by displacing a valve core using thermosensitive wax whose volume changes with temperature.

[0048] The electric heater 25 is an auxiliary heating unit that assists in heating the coolant in the high-temperature coolant circuit 20. The electric heater 25 is an auxiliary heat source for heating the air via the heater core 22. A PTC heater, for example, that generates heat when supplied with electricity can be used as the electric heater 25. The electric heater 25 is a Joule heat generator that generates Joule heat. The amount of heat generated by the electric heater 25 is controlled by a control voltage output from the control device 60.

[0049] The low-temperature cooling water circuit 30 is provided with a cooler 17 , a low-temperature side pump 31 , a low-temperature side radiator 32 , a battery 33 , a power transmission pump 34 , an inverter 35 , an electric generator 36 , a battery three-way valve 37 , a power transmission three-way valve 38 , and a bypass three-way valve 39 .

[0050] The low-temperature-side pump 31 is a heat medium pump that draws in and discharges cooling water. It is an electric pump. It functions as a low-temperature-side flow rate regulator, regulating the flow rate of cooling water circulating in the low-temperature cooling water circuit 30. The low-temperature-side radiator 32 is a low-temperature heat medium-to-outside air heat exchanger, exchanging heat between the cooling water in the low-temperature cooling water circuit 30 and the outside air.

[0051] Battery 33 is an onboard device installed in the vehicle and generates heat during operation. Battery 33 dissipates the waste heat generated during operation into the cooling water in low-temperature cooling water circuit 30. In other words, battery 33 supplies heat to the cooling water in low-temperature cooling water circuit 30.

[0052] The power transmission pump 34 is a heat medium pump that sucks in cooling water and discharges the cooling water so as to circulate the cooling water to the inverter 35 and the motor generator 36 as power transmission devices.

[0053] The low-temperature-side radiator 32, battery 33, inverter 35, motor generator 36, and bypass flow path 30a are arranged in parallel with each other in the flow of cooling water. The battery three-way valve 37, powertrain three-way valve 38, and bypass three-way valve 39 serve as the heat medium flow switching unit that switches the flow of cooling water in the low-temperature cooling water circuit 30.

[0054] The battery three-way valve 37 switches the flow of cooling water to the battery 33. The powertrain three-way valve 38 switches the flow of cooling water to the inverter 35 and the motor generator 36. The bypass three-way valve 39 switches the flow of cooling water to the bypass flow path 30a.

[0055] The operations of the battery three-way valve 37 , the powertrain three-way valve 38 , and the bypass three-way valve 39 are controlled by a control device 60 .

[0056] The first evaporator 14 and the heater core 22 are housed in a housing 51 of an indoor air conditioning unit 50 (hereinafter referred to as the air conditioning housing). The indoor air conditioning unit 50 is located inside an instrument panel (not shown) in the front portion of the vehicle interior. The air conditioning housing 51 is an air passage forming member that forms an air passage.

[0057] The heater core 22 is positioned in the air passage within the air conditioner casing 51, downstream of the first evaporator 14 in the air flow. The air conditioner casing 51 is provided with an inside / outside air switching box 52 and an indoor blower 53. The inside / outside air switching box 52 includes an inside / outside air switching door 52a. The inside / outside air switching door 52a is an inside / outside air switching unit that switches between inside air and outside air introduced into the air passage within the air conditioner casing 51. The inside / outside air switching door 52a is an inside / outside air adjustment unit that adjusts the ratio of inside air to outside air introduced into the air passage within the air conditioner casing 51.

[0058] The indoor blower 53 draws in and blows in the inside and outside air introduced into the air passage of the air conditioning casing 51 through the inside and outside air switching box 52 . The inside and outside air switching door 52 a and the indoor blower 53 are controlled by the control device 60 .

[0059] An air mix door 54 is provided in the air passage within the air conditioner casing 51 between the first evaporator 14 and the heater core 22. The air mix door 54 adjusts the air volume ratio of the cold air that has passed through the first evaporator 14 and flows into the heater core 22 to the cold air that flows through the cold air bypass passage 55.

[0060] The cold air bypass passage 55 is an air passage that allows the cold air that has passed through the first evaporator 14 to flow around the heater core 22 .

[0061] The air mix door 54 is a rotary door having a rotational shaft rotatably supported by the air conditioning housing 51 and a door base plate coupled to the rotational shaft. By adjusting the opening position of the air mix door 54, the temperature of the conditioned air blown from the air conditioning housing 51 into the vehicle interior can be adjusted to a desired temperature.

[0062] The rotation shaft of the air mix door 54 is driven by a servo motor, and the operation of the servo motor is controlled by a control device 60 .

[0063] The air mix door 54 may be a sliding door that slides in a direction substantially perpendicular to the air flow. The sliding door may be a plate-shaped door formed of a rigid body or a film door formed of a flexible film material.

[0064] The conditioned air, the temperature of which has been adjusted by the air mix door 54 , is blown out into the vehicle interior from an air outlet 56 formed in the air conditioning casing 51 .

[0065] Figure 2 The control device 60 shown is composed of a conventional microcomputer including a CPU, ROM, RAM, and other components, and its peripheral circuits. The control device 60 performs various calculations and processes based on the control program stored in the ROM. The output side of the control device 60 is connected to various controlled devices. The control device 60 serves as a control unit that controls the operation of the various controlled devices.

[0066] The control object equipment controlled by the control device 60 is the compressor 11, the first expansion valve 13, the second expansion valve 16, the high-temperature side pump 21, the opening and closing valve 24, the electric heater 25, the low-temperature side pump 31, the power transmission pump 34, the three-way valve 37 for the battery, the three-way valve 38 for the power transmission, the three-way valve 39 for bypass, the internal and external air switching door 52a and the indoor blower 53, etc.

[0067] The software and hardware controlling the motor of the compressor 11 in the control device 60 constitute the refrigerant discharge capacity control unit 60a. The software and hardware controlling the first expansion valve 13 in the control device 60 constitute the first throttle control unit 60b. The software and hardware controlling the second expansion valve 16 in the control device 60 constitute the second throttle control unit 60c. The second throttle control unit 60c is a cooling switching unit that switches between a cooler cooling state, in which the coolant is cooled by the cooler 17, and a cooler non-cooling state, in which the coolant is not cooled by the cooler 17.

[0068] The software and hardware for controlling the high-temperature side pump 21 in the control device 60 constitute a high-temperature heat medium flow rate control unit. The software and hardware for controlling the on-off valve 24 in the control device 60 constitute an on-off valve control unit.

[0069] The software and hardware controlling the electric heater 25 in the control device 60 constitute the auxiliary heating control unit. The software and hardware controlling the low-temperature-side pump 31 in the control device 60 constitute the first heat medium flow control unit 60d. The software and hardware controlling the powertrain pump 34 in the control device 60 constitute the second heat medium flow control unit 60e. The software and hardware controlling the battery three-way valve 37, the powertrain three-way valve 38, and the bypass three-way valve 39 in the control device 60 constitute the heat medium flow control unit 60f. The heat medium flow control unit 60f is the circuit switching determination unit, which determines the switching of the cooling water circulation state in the low-temperature cooling water circuit 30.

[0070] Connected to the input side of the control device 60 are various control sensor groups, including an internal air temperature sensor 61, an external air temperature sensor 62, a sunlight amount sensor 63, a first evaporator temperature sensor 64, a second evaporator temperature sensor 65, a low-temperature cooling water temperature sensor 66, and a battery temperature sensor 67.

[0071] The interior air temperature sensor 61 detects the vehicle interior temperature Tr. The exterior air temperature sensor 62 detects the exterior air temperature Tam. The solar radiation amount sensor 63 detects the solar radiation amount As in the vehicle interior.

[0072] The first evaporator temperature sensor 64 is a temperature detection unit that detects the temperature TE1 (hereinafter referred to as the first evaporator temperature) of the first evaporator 14. The first evaporator temperature sensor 64 is, for example, a fin thermistor that detects the temperature of the heat exchange fins of the first evaporator 14 or a refrigerant temperature sensor that detects the temperature of the refrigerant flowing through the first evaporator 14.

[0073] The second evaporator temperature sensor 65 is a temperature detector that detects the temperature TE2 (hereinafter referred to as the second evaporator temperature) of the cooler 17. The second evaporator temperature sensor 65 is, for example, a refrigerant temperature sensor that detects the temperature of the refrigerant flowing through the cooler 17.

[0074] The low-temperature cooling water temperature sensor 66 is a temperature detection unit that detects the temperature TW of the cooling water in the low-temperature cooling water circuit 30 . For example, the low-temperature cooling water temperature sensor 66 detects the temperature of the cooling water in the cooler 17 .

[0075] The battery temperature sensor 67 is a battery temperature detection unit that detects the temperature TB of the battery 33. The battery temperature sensor 67 is preferably composed of a plurality of temperature sensors that detect the temperatures of a plurality of locations of the battery 33.

[0076] The input side of the control device 60 is connected to various operating switches provided on an operating panel 68. The various operating switches are operated by the occupants. The operating panel 68 is located near the instrument panel at the front of the vehicle interior. The control device 60 receives input of operating signals from the various operating switches.

[0077] The various operation switches include a driving mode setting switch, an air conditioning switch, a temperature setting switch, etc. The driving mode setting switch is a switch for switching the driving mode of the vehicle to an energy-saving mode, a normal mode, or a sport mode.

[0078] The eco mode prioritizes energy saving and appropriately suppresses the output of the motor generator 36. The sport mode does not prioritize energy saving and does not limit the output of the motor generator 36. The normal mode is a driving mode between the eco mode and the sport mode.

[0079] The air conditioning switch is a switch for setting whether or not to cool the air by the indoor air conditioning unit 50. The temperature setting switch is a switch for setting the set temperature in the vehicle interior.

[0080] The input side and the output side of the control device 60 are connected to a power transmission control device 70. The power transmission control device 70 is a power transmission control unit that controls the inverter 35 and the motor generator 36 as power transmission devices.

[0081] The control device 60 receives an input of a requested output value of the motor generator 36 from the powertrain control device 70. An inverter temperature sensor 71 and a motor generator temperature sensor 72 are connected to the input side of the powertrain control device 70.

[0082] The inverter temperature sensor 71 is a power transmission device temperature detection unit that detects the temperature of the inverter 35 . The motor generator temperature sensor 72 is a power transmission device temperature detection unit that detects the temperature of the motor generator 36 .

[0083] Detection signals from the inverter temperature sensor 71 and the motor generator temperature sensor 72 are input to the control device 60 via the powertrain control device 70 .

[0084] The input side of the control device 60 is connected to the car navigation device 75. Map information, traffic congestion information, etc. are input to the control device 60 from the car navigation device 75.

[0085] The information processed by control device 60 includes the required output value of motor generator 36, the temperature of inverter 35, the temperature of motor generator 36, map information, and traffic congestion information.

[0086] Next, the operation of the above-described structure will be described. First, an overview of the operation related to the air conditioner will be described. The control device 60 determines the operating states of various control devices connected to the control device 60 (control signals output to the various control devices) based on the target air outlet temperature TAO, detection signals from the sensor group, and the like.

[0087] The target air temperature TAO is the target temperature of the air blown into the vehicle interior. The target air temperature TAO is an indicator of the air conditioning load (in other words, the air conditioning heat load) required of the vehicle air conditioner 1. The control device 60 calculates the target air temperature TAO based on the following equation F1. TAO=Kset×Tset-Kr×Tr-Kam×Tam-Ks×As+C...(F1) In this mathematical formula, Tset is the vehicle interior temperature set by the temperature setting switch on the operation panel 68, Tr is the interior air temperature detected by the interior air temperature sensor 61, Tam is the exterior air temperature detected by the exterior air temperature sensor 62, and As is the amount of solar radiation detected by the solar radiation sensor 63. Kset, Kr, Kam, and Ks are control gains, and C is a correction constant.

[0088] Based on the deviation between the target temperature TEO and the temperature TE1 of the first evaporator 14 , a control signal output to the compressor 11 (in other words, the rotation speed of the compressor 11 ) is determined by a feedback control method so that the temperature TE1 of the first evaporator 14 approaches the target temperature TEO.

[0089] Based on the target air outlet temperature TAO, the target temperature TEO is determined by referring to a control map stored in the control device 60. In the control map of the present embodiment, the target temperature TEO is determined so that the target temperature TEO increases as the target air outlet temperature TAO increases.

[0090] In the refrigeration cycle device 10 in the air-conditioning mode, the state of the refrigerant circulating in the circulation system changes as follows.

[0091] The high-pressure refrigerant discharged from the compressor 11 flows into the condenser 12. The refrigerant flowing into the condenser 12 transfers heat to the cooling water in the high-temperature cooling water circuit 20. As a result, the refrigerant is cooled in the condenser 12 and condensed.

[0092] The refrigerant flowing out of the condenser 12 flows into the first expansion valve 13, where it is decompressed and expanded to become low-pressure refrigerant. The low-pressure refrigerant, decompressed by the first expansion valve 13, flows into the first evaporator 14, where it absorbs heat from the air being blown into the vehicle interior and evaporates. This cools the air being blown into the vehicle interior.

[0093] The refrigerant flowing out of the first evaporator 14 flows toward the suction side of the compressor 11 and is compressed again by the compressor 11 .

[0094] The cooling water of the high-temperature cooling water circuit 20 that has removed heat from the refrigerant in the condenser 12 circulates to the heater core 22 . In the heater core 22 , the air cooled by the first evaporator 14 is heated by the cooling water of the high-temperature cooling water circuit 20 .

[0095] As described above, the low-pressure refrigerant absorbs heat from the air in the first evaporator 14 to cool the air, and the cooled air is heated by the heater core 22 and blown into the vehicle interior.

[0096] Next, the operation related to cooling the inverter 35 and the motor generator 36 will be described. The controller 60 switches the operating mode of the refrigeration cycle device 10 between a cooler-on mode and a cooler-off mode. In the cooler-on mode, since the second expansion valve 16 is at a throttled opening, the low-pressure refrigerant, which has been decompressed and expanded by the second expansion valve 16, flows into the cooler 17, cooling the coolant in the low-temperature cooling water circuit 30. In the cooler-off mode, since the second expansion valve 16 is fully closed, the refrigerant does not flow into the cooler 17, cooling the coolant in the low-temperature cooling water circuit 30.

[0097] The control device 60 switches the circulation mode of the cooling water to the inverter 35 and the motor generator 36 of the low-temperature cooling water circuit 30 to either a radiator heat dissipation mode or a cooler cooling mode. The radiator heat dissipation mode is the first circulation state of the low-temperature cooling water circuit 30, and the cooler cooling mode is the second circulation state of the low-temperature cooling water circuit 30.

[0098] In the radiator cooling mode, the power transmission pump 34 is operated, and Figure 3 As shown by the dotted arrows, the power transmission three-way valve 38 is switched so that the cooling water circulates between the inverter 35 and the motor generator 36 and the low-temperature side radiator 32. As a result, the heat generated by the inverter 35 and the motor generator 36 is dissipated to the outside air through the low-temperature side radiator 32.

[0099] In the radiator heat dissipation mode, when the operation mode of the refrigeration cycle device 10 is the cooler on mode, the low temperature side pump 31 is operated, and Figure 4 As shown by the dotted arrow, the bypass three-way valve 39 is switched so that the cooling water circulates between the cooler 17 and the bypass flow path 30a. As a result, the temperature of the cooling water circulating between the cooler 17 and the bypass flow path 30a is lowered.

[0100] In the cooler cooling mode, at least one of the low temperature side pump 31 and the power transmission pump 34 is operated, and Figure 5 As shown by the dotted arrows, the power transmission three-way valve 38 is switched so that the cooling water circulates between the inverter 35 and the motor generator 36 and the cooler 17. As a result, the heat dissipated by the inverter 35 and the motor generator 36 is absorbed by the refrigerant in the refrigeration cycle device 10 in the cooler 17.

[0101] In the cooler cooling mode, the refrigeration cycle device 10 is used to cool the inverter 35 and the motor generator 36. Therefore, compared with the radiator heat dissipation mode in which the heat of the inverter 35 and the motor generator 36 is dissipated to the outside air, the cooling capacity of the inverter 35 and the motor generator 36 is higher.

[0102] Figure 6 1 is a flowchart showing a control process executed by the control device 60. In step S100, the temperature of the inverter 35 detected by the inverter temperature sensor 71 and the temperature of the motor generator 36 detected by the motor generator temperature sensor 72 are acquired.

[0103] In step S110, the change in the required output of the motor generator 36 is predicted based on map information or traffic information input from the in-vehicle navigation device 75. For example, when traveling on a road with a high speed limit, such as an expressway, the required output of the motor generator 36 is predicted to increase, and when traveling on a congested road, the required output of the motor generator 36 is predicted to decrease.

[0104] In step S120, the temperature changes of inverter 35 and motor generator 36 are predicted based on the required output of motor generator 36 predicted in step S110. For example, the higher the predicted required output of motor generator 36, the higher the temperature of inverter 35 and motor generator 36 are predicted to be.

[0105] In step S130, it is determined whether the temperatures of inverter 35 and motor generator 36 predicted in step S110 exceed threshold PT. Threshold PT is the temperature of inverter 35 and motor generator 36 when the cooling capacity of inverter 35 and motor generator 36 is insufficient in the radiator heat dissipation mode.

[0106] If it is determined in step S130 that the predicted temperature of the inverter 35 and the motor generator 36 does not exceed the threshold value PT, the process proceeds to steps S140 to S150, where the operation mode of the refrigeration cycle device 10 is set to the cooler off mode, and the circulation mode of the low-temperature cooling water circuit 30 is set to the radiator heat dissipation mode. Figure 3 As shown, heat generated by the inverter 35 and the motor generator 36 is dissipated to the outside air via the low-temperature-side radiator 32 .

[0107] If it is determined in step S130 that the predicted temperature of the inverter 35 and the motor generator 36 exceeds the threshold value PT, the process proceeds to step S160, and the operation mode of the refrigeration cycle device 10 is set to the cooler ON mode. Figure 4 As shown, the cooling water in the low-temperature cooling water circuit 30 is cooled by the cooler 17 .

[0108] Next, in step S170 , it is determined whether the temperature of the inverter 35 detected by the inverter temperature sensor 71 and the temperature of the motor generator 36 detected by the motor generator temperature sensor 72 exceed a threshold value PT.

[0109] If it is determined in step S170 that the temperature of the inverter 35 and the temperature of the motor generator 36 do not exceed the threshold value PT, the process proceeds to step S180, and the circulation mode of the low-temperature cooling water circuit 30 is set to the radiator heat dissipation mode. Figure 4 As shown, heat generated by the inverter 35 and the motor generator 36 is dissipated to the outside air via the low-temperature-side radiator 32 .

[0110] If it is determined in step S170 that the temperature of the inverter 35 and the temperature of the motor generator 36 exceed the threshold value PT, the process proceeds to step S190, and the circulation mode of the low-temperature cooling water circuit 30 is set to the cooler cooling mode. Figure 5 As shown, the inverter 35 and the motor generator 36 are cooled by the cooling water cooled by the cooler 17 of the refrigeration cycle device 10 .

[0111] In the cooler on mode, the control device 60 controls the second expansion valve 16 so that the cooling water temperature of the low-temperature cooling water circuit 30 approaches the target temperature. Figure 7 The control processing shown in the flowchart is determined.

[0112] In step S200, thermophysical property information is acquired for inverter 35 and motor generator 36. The thermophysical property information is information related to an efficiency map (ie, a map showing the relationship between output and heat generation), an allowable upper limit temperature, and thermal resistance.

[0113] In step S210 , the output value required of the motor generator 36 is acquired from the powertrain control device 70 .

[0114] In step S220, the heat generated by inverter 35 and motor generator 36 is calculated. Specifically, the heat generated by inverter 35 and motor generator 36 is calculated based on the efficiency maps of inverter 35 and motor generator 36 acquired in step S200 and the required output value of motor generator 36 acquired in step S210.

[0115] In step S230, the target temperature of the cooling water in the low-temperature cooling water circuit 30 is determined using the following equation F2 based on the allowable upper temperature limits and thermal resistances of the inverter 35 and the motor generator 36 acquired in step S200 and the heating values ​​of the inverter 35 and the motor generator 36 calculated in step S220. Target temperature = allowable upper limit temperature - heat generation × thermal resistance (F2) Figure 8 A control example of this embodiment is shown below. In this control example, as the predicted output of the motor generator 36 increases, the predicted temperatures of the inverter 35 and the motor generator 36 also increase. When the predicted temperatures of the inverter 35 and the motor generator 36 exceed the threshold value PT, the operating mode of the refrigeration cycle device 10 is set to the cooler-on mode, thereby reducing the cooling water temperature in the low-temperature cooling water circuit 30. The cooling water temperature in the low-temperature cooling water circuit 30 is controlled to approach the target temperature determined in step S220.

[0116] When the temperature of the inverter 35 and the motor generator 36 exceeds the threshold value PT, the circulation mode of the low-temperature cooling water circuit 30 is switched from the radiator heat dissipation mode to the cooler cooling mode. This improves the cooling capacity of the inverter 35 and the motor generator 36, thereby preventing the temperature of the inverter 35 and the motor generator 36 from exceeding the threshold value PT.

[0117] Thereafter, as the predicted output of the motor generator 36 decreases, the predicted temperatures of the inverter 35 and the motor generator 36 also decrease. Then, when the predicted temperatures of the inverter 35 and the motor generator 36 fall below the threshold value PT, the operation mode of the refrigeration cycle device 10 is set to the cooler off mode. When the actual temperatures of the inverter 35 and the motor generator 36 fall below the threshold value PT, the circulation mode of the low-temperature cooling water circuit 30 is switched from the cooler cooling mode to the radiator heat dissipation mode.

[0118] Thus, heat generated by the inverter 35 and the motor generator 36 is dissipated to the outside air without using the refrigeration cycle device 10 , thereby saving energy in cooling the inverter 35 and the motor generator 36 .

[0119] As can be seen from the description of steps S110 to S160, in this embodiment, the control device 60 determines the cooler cooling start time based on the driving state-related information. The cooler cooling start time is the time when the operating mode of the refrigeration cycle device 10 is switched from the cooler-off mode to the cooler-on mode. The driving state-related information includes map information or congestion information input from the in-vehicle navigation device 75.

[0120] As a result, the inverter 35 and the motor generator 36 can be cooled based on the information related to the driving state, so the inverter 35 and the motor generator 36 can be cooled efficiently.

[0121] In this embodiment, as can be seen from the description of steps S160 to S190 , the cooler cooling start time is the time before the circulation mode of the low-temperature cooling water circuit 30 is switched from the radiator heat radiation mode to the cooler cooling mode.

[0122] Thus, since the cooling water in the low-temperature cooling water circuit 30 is cooled in advance before starting to cool the inverter 35 and the motor generator 36 , the inverter 35 and the motor generator 36 can be cooled quickly.

[0123] In this embodiment, as is apparent from the description of steps S130 to S140 , the cooler cooling start timing is the timing at which the temperatures of the inverter 35 and the motor generator 36 exceed the threshold value PT, as predicted based on the driving state related information.

[0124] Thus, since the cooler cooling start time is determined based on the predicted temperatures of the inverter 35 and the motor generator 36 , the inverter 35 and the motor generator 36 can be cooled more quickly than when the cooler cooling start time is determined based on the actual temperatures of the inverter 35 and the motor generator 36 .

[0125] In the present embodiment, as is apparent from the description of steps S200 to S230 , the control device 60 determines the target temperature of the cooling water based on the predicted temperatures of the inverter 35 and the motor generator 36 .

[0126] Thus, compared to a case where the target temperature of the cooling water is determined based on the actual temperatures of the inverter 35 and the motor generator 36 , the cooling water can be cooled to the target temperature more quickly.

[0127] (Second embodiment) In the above embodiment, when it is determined that the predicted temperatures of the inverter 35 and the motor generator 36 exceed the threshold value PT, the operation mode of the refrigeration cycle device 10 is set to the cooler-on mode.

[0128] In contrast, in this embodiment, the time when the temperature of the inverter 35 and the motor generator 36 reaches the threshold value PT is predicted, and the operation mode of the refrigeration cycle device 10 is set to the cooler-on mode so that the cooling water is cooled to the target temperature before reaching this time.

[0129] Figure 9 1 is a flowchart showing the control process executed by the control device 60 in this embodiment. Steps S100 to S110 are the same as those in the first embodiment.

[0130] Next, in step S135, based on the required output of the motor generator 36 predicted in step S110, the changes in the temperature of the inverter 35 and the motor generator 36 are predicted, and the time when the temperatures of the inverter 35 and the motor generator 36 reach the threshold value PT (hereinafter referred to as the arrival time) is predicted.

[0131] In step S136, the time to switch the operating mode of the refrigeration cycle device 10 to the cooler-on mode (hereinafter referred to as the switching time) is determined. The switching time is the time required to cool the cooling water to the target temperature, looking back from the arrival time. Therefore, if the operating mode of the refrigeration cycle device 10 is switched to the cooler-on mode at the switching time, the cooling water will be cooled to the target temperature at the arrival time.

[0132] In step S137, it is determined whether the current time is the switching time. If it is determined in step S137 that the current time is not the switching time, the process proceeds to steps S140 to S150, where the operation mode of the refrigeration cycle device 10 is set to the cooler off mode, and the circulation mode of the low-temperature cooling water circuit 30 is set to the radiator heat dissipation mode. Figure 3 As shown, heat generated by the inverter 35 and the motor generator 36 is dissipated to the outside air via the low-temperature-side radiator 32 .

[0133] If it is determined in step S137 that the current time is the switching time, the process proceeds to step S160 to set the operation mode of the refrigeration cycle device 10 to the cooler on mode. Figure 4 As shown, the cooling water in the low-temperature cooling water circuit 30 is cooled by the cooler 17. Steps S170 to S190 are the same as those in the first embodiment.

[0134] In this embodiment, as is apparent from the description of steps S135 to S160 , the control device 60 determines the cooler cooling start timing so that the cooling water can be cooled to the target temperature before the temperatures of the inverter 35 and the motor generator 36 reach the threshold value PT.

[0135] Thus, when the temperatures of the inverter 35 and the motor generator 36 reach the threshold value PT, cooling water at the target temperature can be immediately supplied to the inverter 35 and the motor generator 36 , thereby rapidly cooling the inverter 35 and the motor generator 36 .

[0136] (Third embodiment) In the above-mentioned first embodiment, as described in steps S130 to S160, when it is determined that the predicted temperature of the inverter 35 and the electric generator 36 exceeds the threshold PT (in other words, when a cooling requirement for cooling water occurs), the operating mode of the refrigeration cycle device 10 is set to the cooler on mode, and the cooling water of the low-temperature cooling water circuit 30 is cooled to a temperature close to the target temperature through the cooler 17.

[0137] In contrast, in this embodiment, before the operation mode of the refrigeration cycle device 10 is set to the cooler-on mode in step S160 of the above-described embodiment (in other words, before a cooling request for the cooling water is issued, such as when the vehicle is started), the cooling water in the low-temperature cooling water circuit 30 is preliminarily cooled to a predetermined temperature or below by the cooler 17. The predetermined temperature is a temperature higher than the target temperature and lower than the outside air temperature.

[0138] Figure 10 1 is a flowchart showing the control process executed by the controller 60 in this embodiment. The control process shown in this flowchart is executed before the operation mode of the refrigeration cycle device 10 is set to the cooler-on mode in step S160 of the above embodiment (i.e., when there is no cooling request from the cooler 17).

[0139] In step S300 , it is determined whether the cooling water temperature in the low-temperature cooling water circuit 30 exceeds a predetermined temperature.

[0140] If it is determined in step S300 that the cooling water temperature of the low-temperature cooling water circuit 30 does not exceed the predetermined temperature, the process proceeds to step S310 to determine whether the cooling water temperature of the low-temperature cooling water circuit 30 is lower than the target temperature.

[0141] If it is determined in step S310 that the cooling water temperature in the low-temperature cooling water circuit 30 is lower than the target temperature, the process proceeds to step S320, where the operating mode of the refrigeration cycle device 10 is set to the chiller-off mode. In other words, since the cooling water temperature in the low-temperature cooling water circuit 30 does not need to be further cooled, the cooling water in the low-temperature cooling water circuit 30 is not cooled by the chiller 17.

[0142] If the cooling water temperature in the low-temperature cooling water circuit 30 is determined to be above the specified temperature in step S300, and if the cooling water temperature in the low-temperature cooling water circuit 30 is determined to be not lower than the target temperature in step S310, the process proceeds to step S330, where the operating mode of the refrigeration cycle device 10 is set to the chiller-on mode. As a result, the cooling water in the low-temperature cooling water circuit 30 is maintained by the chiller 17 at a temperature above the target temperature and below the specified temperature.

[0143] Figure 11 A control example of this embodiment is shown below. In this control example, since the cooling water temperature in the low-temperature cooling water circuit 30 is approximately the same as the outside air temperature and exceeds a predetermined temperature at vehicle startup, the operating mode of the refrigeration cycle device 10 is set to the cooler-on mode. As a result, the cooling water in the low-temperature cooling water circuit 30 is cooled by the cooler 17, thereby reducing the cooling water temperature.

[0144] When the temperature of the cooling water in the low-temperature cooling water circuit 30 is lower than the target temperature, the operation mode of the refrigeration cycle device 10 is set to the cooler-off mode.

[0145] When the cooling water temperature in the low-temperature cooling water circuit 30 exceeds a predetermined temperature, the operation mode of the refrigeration cycle device 10 is set to the cooler-on mode.

[0146] By repeatedly switching between the cooler on mode and the cooler off mode, the cooling water temperature in the low-temperature cooling water circuit 30 is maintained between the target temperature and the predetermined temperature. Furthermore, when the operation mode of the refrigeration cycle device 10 is set to the cooler on mode in step S160 of the above embodiment (in other words, when a cooling request for the cooling water is generated), the switching between the cooler on mode and the cooler off mode is completed, and the cooler on mode is continued.

[0147] At this time, the cooling water temperature of the low-temperature cooling water circuit 30 is not substantially the same as the outside air temperature, but is cooled to a temperature between the target temperature and the predetermined temperature. Therefore, the cooling water temperature of the low-temperature cooling water circuit 30 can quickly reach the target temperature.

[0148] If the operating mode of the refrigeration cycle device 10 is set to the cooler off mode when the temperature of the cooling water in the low-temperature cooling water circuit 30 is lower than the target temperature, and the low-temperature side pump 31 is stopped to stop the circulation of the cooling water in the low-temperature cooling water circuit 30, the rise in the temperature of the cooling water in the low-temperature cooling water circuit 30 can be suppressed.

[0149] In the present embodiment, the control device 60 determines the switching between the cooler ON mode and the cooler OFF mode so that the temperature of the coolant in the low-temperature coolant circuit 30 is equal to or lower than a predetermined temperature after the vehicle is started and before the cooler cooling starts.

[0150] Thus, since the cooling water is cooled in advance after the vehicle is started, the inverter 35 and the motor generator 36 can be cooled more quickly.

[0151] In this embodiment, cooling of the coolant in the low-temperature coolant circuit 30 is started when the vehicle starts, but cooling of the coolant in the low-temperature coolant circuit 30 may also be started during pre-air conditioning. Pre-air conditioning refers to air conditioning performed before passengers enter the vehicle.

[0152] (Fourth embodiment) In the above-mentioned third embodiment, before the operating mode of the refrigeration cycle device 10 is set to the cooler on mode in step S160 of the above-mentioned embodiment (i.e., before the inverter 35 and the electric generator 36 need to be forced to cool), the cooling water of the low-temperature cooling water circuit 30 is pre-cooled to above the target temperature and below the specified temperature through the cooler 17.

[0153] In the present embodiment, before forced cooling of the inverter 35 and the motor generator 36 becomes necessary, the cooling water in the low-temperature cooling water circuit 30 is cooled in advance by the cooler 17 to a temperature range lower than the outside air temperature.

[0154] Specifically, the coolant in the low-temperature cooling water circuit 30 is cooled by the cooler 17 so that the difference between the coolant and the outside air temperature is within a range of not less than a first temperature difference α1 and not more than a second temperature difference α2. The second temperature difference α2 is smaller than the temperature difference between the outside air temperature and the target temperature. The first temperature difference α1 is smaller than the temperature difference between the outside air temperature and the target temperature and larger than the second temperature difference α2.

[0155] Figure 12 1 is a flowchart illustrating the control process executed by the controller 60 in this embodiment. The control process illustrated in this flowchart is executed before the operation mode of the refrigeration cycle device 10 is set to the cooler-on mode in step S160 of the above embodiment (i.e., when there is no cooling request from the cooler 17).

[0156] In step S400, it is determined whether forced cooling is required for inverter 35 and motor generator 36. For example, when the temperature of inverter 35 and motor generator 36 exceeds threshold value PT, it is determined that forced cooling of inverter 35 and motor generator 36 is required.

[0157] If it is determined in step S400 that forced cooling of the inverter 35 and the motor generator 36 is not required, the process proceeds to step S410 to determine whether the cooling water temperature of the low-temperature cooling water circuit 30 exceeds the outside air temperature minus the second temperature difference α2.

[0158] If it is determined in step S410 that the cooling water temperature of the low-temperature cooling water circuit 30 does not exceed the outside air temperature minus the second temperature difference α2, the process proceeds to step S420 to determine whether the cooling water temperature of the low-temperature cooling water circuit 30 is lower than the outside air temperature minus the first temperature difference α1.

[0159] If it is determined in step S420 that the coolant temperature of the low-temperature coolant circuit 30 is lower than the outside air temperature minus the first temperature difference α1 , the process proceeds to step S430 to set the operation mode of the refrigeration cycle device 10 to the cooler-off mode.

[0160] When it is determined in step S410 that the cooling water temperature of the low-temperature cooling water circuit 30 exceeds the external air temperature - the second temperature difference α2, and when it is determined in step S420 that the cooling water temperature of the low-temperature cooling water circuit 30 is not lower than the external air temperature - the first temperature difference α1, step S440 is entered to set the operation mode of the refrigeration cycle device 10 to the cooler on mode.

[0161] If forced cooling of the inverter 35 and motor generator 36 is determined to be necessary in step S400, the process proceeds to step S450, where the operating mode of the refrigeration cycle device 10 is set to the cooler-on mode. In step S460, the circulation mode of the low-temperature cooling water circuit 30 is switched from the radiator heat dissipation mode to the cooler cooling mode. As a result, the cooling water in the low-temperature cooling water circuit 30 is cooled by the cooler 17 to a temperature close to the target temperature, and the cooling water cooled by the cooler 17 cools the inverter 35 and motor generator 36.

[0162] Figure 13 The following describes a control example of this embodiment. In this control example, since the coolant temperature in the low-temperature cooling water circuit 30 is approximately the same as the outside air temperature and exceeds the outside air temperature minus the second temperature difference α2 at vehicle startup, the operating mode of the refrigeration cycle device 10 is set to the cooler-on mode. As a result, the coolant in the low-temperature cooling water circuit 30 is cooled by the cooler 17, reducing the coolant temperature.

[0163] When the temperature of the cooling water in the low-temperature cooling water circuit 30 is lower than the outside air temperature minus the first temperature difference α1, the operation mode of the refrigeration cycle device 10 is set to the cooler-off mode. As a result, the cooling water in the low-temperature cooling water circuit 30 is not cooled by the cooler 17, and the cooling water temperature rises.

[0164] When the cooling water temperature in the low-temperature cooling water circuit 30 exceeds the outside air temperature minus the second temperature difference α2, the operation mode of the refrigeration cycle device 10 is set to the cooler-on mode.

[0165] By repeatedly switching between the cooler-on mode and the cooler-off mode, the coolant temperature in the low-temperature cooling water circuit 30 is maintained between the outside air temperature - the first temperature difference α1 and the outside air temperature - the second temperature difference α2. Furthermore, when the refrigeration cycle device 10's operating mode is set to the cooler-on mode in step S160 of the above-described embodiment, the cooler-on mode / cooler-off mode switching is completed, and the cooler-on mode resumes. At this point, the coolant temperature in the low-temperature cooling water circuit 30 is not approximately the same as the outside air temperature, but rather between the outside air temperature - the first temperature difference α1 and the outside air temperature - the second temperature difference α2. This allows the coolant temperature in the low-temperature cooling water circuit 30 to quickly reach the target temperature.

[0166] According to this embodiment, when pre-cooling the cooling water in the low-temperature cooling water circuit 30 before forced cooling of the inverter 35 and the motor generator 36 is required, a certain temperature difference with the outside air temperature can be maintained. In other words, the cooling water in the low-temperature cooling water circuit 30 is maintained at a temperature higher than the target temperature. This achieves energy savings compared to the aforementioned third embodiment, in which the cooling water in the low-temperature cooling water circuit 30 is cooled to the target temperature before forced cooling of the inverter 35 and the motor generator 36 is required.

[0167] (Fifth embodiment) In the above embodiment, the coolant temperature of the low-temperature coolant circuit 30 is controlled to approach the target temperature in the cooler cooling mode. However, in this embodiment, the target temperature is switched according to the driving mode set by the occupant.

[0168] Figure 14 1 is a flowchart showing the control process executed by the control device 60 in this embodiment. In step S500, the driving mode selected by the occupant is acquired. In step S510, it is determined whether the driving mode is the energy-saving mode.

[0169] If it is determined in step S510 that the running mode is the energy-saving mode, the process proceeds to step S520 , where the target temperature of the cooling water in the low-temperature cooling water circuit 30 is set to the energy-saving mode temperature LT3 .

[0170] If the driving mode is not the energy-saving mode in step S510, the process proceeds to step S530 to determine whether the driving mode is the sport mode. If the driving mode is the sport mode in step S530, the process proceeds to step S540 to set the target temperature of the coolant in the low-temperature cooling water circuit 30 to the sport mode temperature LT1. The sport mode temperature LT1 is lower than the energy-saving mode temperature LT3.

[0171] If it is determined in step S530 that the driving mode is not the sport mode (i.e., the driving mode is the normal mode), the process proceeds to step S550, where the target temperature of the coolant in the low-temperature cooling water circuit 30 is set to the normal mode temperature LT2. The normal mode temperature LT2 is higher than the sport mode temperature LT1 and lower than the energy-saving mode temperature LT3.

[0172] By performing such control processing, Figure 15 As shown, the temperature of the coolant in the low-temperature coolant circuit 30 is a sports mode temperature LT1 in the sports mode, a normal mode temperature LT2 higher than the sports mode temperature LT1 in the normal mode, and an energy-saving mode temperature LT3 higher than the normal mode temperature LT2 in the energy-saving mode.

[0173] Therefore, in the sport mode, the cooling capacity of the inverter 35 and the motor generator 36 can be increased, so that the motor generator 36 can be operated at a high output. In the energy-saving mode, the cooling capacity of the inverter 35 and the motor generator 36 can be suppressed to achieve energy saving.

[0174] In this embodiment, the control device 60 determines the target temperature of the coolant in the low-temperature coolant circuit 30 based on the vehicle's driving mode, and therefore determines the cooling start timing based on the driving state-related information and the vehicle's driving mode.

[0175] This allows the cooling water in the low-temperature cooling water circuit 30 to be cooled at a time that matches the vehicle's driving mode. Furthermore, the cooling water can be cooled to a temperature that matches the vehicle's driving mode. Consequently, the inverter 35 and the motor generator 36 can be appropriately cooled according to the vehicle's driving mode.

[0176] In the present embodiment, the target temperature of the cooling water is determined based on the three driving modes of the eco mode, normal mode, and sport mode. However, the target temperature of the cooling water may be determined based on the two driving modes of the eco mode and sport mode.

[0177] In this embodiment, as described in steps S520 to S530, when it is determined that the vehicle's driving mode is the energy-saving mode, the target temperature of the cooling water in the low-temperature cooling water circuit 30 is set to the energy-saving mode temperature LT3. However, when it is determined that the vehicle's driving mode is the energy-saving mode, the target temperature of the cooling water in the low-temperature cooling water circuit 30 may not be set, and the cooling water temperature in the low-temperature cooling water circuit 30 may be left to its own devices.

[0178] Alternatively, if it is determined that the vehicle's driving mode is the energy-saving mode, the target temperature of the cooling water in the low-temperature cooling water circuit 30 may be set to a target temperature for battery cooling if cooling of the battery 33 is required, and the target temperature of the cooling water in the low-temperature cooling water circuit 30 may be set to the same temperature as the outside air temperature if cooling of the battery 33 is not required. When the target temperature of the cooling water in the low-temperature cooling water circuit 30 is set to the same temperature as the outside air temperature, the cooling water in the low-temperature cooling water circuit 30 is not cooled by the cooler 17, but rather is dissipated to the outside air by the low-temperature-side radiator 32.

[0179] (Sixth embodiment) In the above embodiment, the battery 33 is cooled by the cooling water of the low-temperature cooling water circuit 30, and the air sent to the vehicle interior is cooled by the first evaporator 14. However, in this embodiment, Figure 16 As shown, the battery 33 is cooled by the cooling water cooled by the first evaporator 14 , and the air blown into the vehicle interior is cooled by the cooling water passing through the low-temperature cooling water circuit 30 .

[0180] The first evaporator 14 in this embodiment is a battery cooler that exchanges heat between the low-pressure refrigerant flowing out of the first expansion valve 13 and the cooling water in the battery cooling water circuit 40. The cooling water in the battery cooling water circuit 40 is a fluid serving as a heat medium. In this embodiment, a liquid containing at least ethylene glycol, dimethylpolysiloxane, or a nanofluid, or an antifreeze liquid, is used as the battery cooling water circuit 40.

[0181] A battery pump 41 is provided in the battery cooling water circuit 40. The battery pump 41 is a heat medium pump that draws in and discharges cooling water.

[0182] The low-temperature cooling water circuit 30 is equipped with a cooler core 45 and a three-way valve 46 for the cooler core. The cooler core 45 is a heat medium-to-air heat exchanger that cools the air supplied to the vehicle interior by exchanging heat between the coolant cooled by the cooler 17 and the air. The three-way valve 46 for the cooler core switches the flow of coolant to the cooler core 45. The operation of the three-way valve 46 is controlled by the control device 60.

[0183] In this embodiment, by applying the control of the above-mentioned embodiment, the same effects as those of the above-mentioned embodiment can be achieved.

[0184] The present disclosure is not limited to the above-described embodiment, and the following various modifications can be made without departing from the gist of the present disclosure.

[0185] In the above embodiment, cooling water is used as the heat medium, but various media such as oil can also be used as the heat medium. Nanofluids can also be used as the heat medium. Nanofluids refer to fluids mixed with nanoparticles with a particle size of nanometers.

[0186] In the refrigeration cycle device 10 of the above embodiment, a chlorofluorocarbon-based refrigerant is used as the refrigerant. However, the type of refrigerant is not limited thereto, and a natural refrigerant such as carbon dioxide or a hydrocarbon-based refrigerant may also be used.

[0187] The refrigeration cycle device 10 of the above embodiment constitutes a subcritical refrigeration cycle in which the high-pressure side refrigerant pressure does not exceed the critical pressure of the refrigerant, but may also constitute a supercritical refrigeration cycle in which the high-pressure side refrigerant pressure exceeds the critical pressure of the refrigerant.

[0188] In the above embodiment, the high-temperature-side radiator 23 and the low-temperature-side radiator 32 are independent radiators. However, the high-temperature-side radiator 23 and the low-temperature-side radiator 32 may be constituted by a single radiator.

[0189] For example, by integrating the tank of the high-temperature-side radiator 23 and the tank of the low-temperature-side radiator 32 with each other, the high-temperature-side radiator 23 and the low-temperature-side radiator 32 can be constituted by a single radiator.

[0190] In the above embodiment, the second expansion valve 16 is integrally formed by a decompression portion for decompressing the refrigerant and a shut-off portion for shutting off the flow of the refrigerant by completely closing the refrigerant flow path. However, the shut-off portion for shutting off the flow of the refrigerant may be independent of the second expansion valve 16 .

[0191] The condenser 12 in the above embodiment is a heat exchanger that exchanges heat between the refrigerant and the cooling water, but the condenser 12 may be a heat exchanger that exchanges heat between the refrigerant and the air.

[0192] In the above embodiment, the battery 33 is cooled by the cooling water cooled by the refrigerant. However, the battery 33 may be directly cooled by the refrigerant or may be cooled by the air cooled by the refrigerant.

[0193] In the above embodiment, the refrigeration cycle device 10 is a receiver cycle system (receiver cycle) including the receiver 18 , but the refrigeration cycle device 10 may be an accumulator cycle system (accumulator cycle) including an accumulator.

[0194] The features of the refrigeration cycle device disclosed in this specification are as follows. (Item 1) A refrigeration cycle device comprises: a heat medium circuit (30) for circulating a heat medium; Power transmission equipment (35, 36), which is an electrical device for generating driving force for the vehicle, and is cooled by the heat medium; a radiator (32) for exchanging heat between the heat medium and external air; a cooler (17) for exchanging heat between the low-pressure refrigerant of the refrigeration cycle and the heat medium; a circuit switching unit (38) for switching the heat medium circuit to a first circulation state in which the heat medium circulates between the power transmission device and the radiator, or to a second circulation state in which the heat medium circulates between the power transmission device and the cooler; a circuit switching decision unit (60f) which, when it is determined that the temperature of the power transmission device exceeds a threshold value (PT) in the first circulation state, decides to switch to the second circulation state through the circuit switching unit; a cooling switching portion (16) that switches between a cooler cooling state in which the heat medium is cooled by the cooler and a cooler non-cooling state in which the heat medium is not cooled by the cooler; and A cooler cooling determination unit (60c) determines a time at which the cooling switching unit switches from the cooler non-cooling state to the cooler cooling state, i.e., a cooler cooling start time, based on information related to the driving state of the vehicle, i.e., driving state related information. (Item 2) The refrigeration cycle device according to item 1, wherein the cooler cooling start timing is a timing before the circuit switching determination unit switches from the first circulation state to the second circulation state. (Item 3) The refrigeration cycle device according to item 1 or 2, wherein the cooler cooling determination unit determines the switching between the cooler non-cooling state and the cooler cooling state in such a manner that the temperature of the heat medium is lower than a predetermined temperature after the vehicle is started and before the cooler cooling start time. (Item 4) The refrigeration cycle device according to any one of items 1 to 3, wherein the cooler cooling start timing is a timing when the temperature of the power transmission device exceeds the threshold value, which is predicted based on the driving state related information. (Item 5) The refrigeration cycle device according to item 4, wherein the cooler cooling determination unit determines the target temperature of the heat medium based on the predicted temperature of the power transmission device. (Item 6) The refrigeration cycle device according to any one of items 1 to 3, wherein the cooler cooling determination unit determines the cooler cooling start timing so that the heat medium can be cooled to a target temperature before the temperature of the power transmission device reaches the threshold value. (Item 7) The refrigeration cycle device according to item 1, wherein the cooler cooling determination unit determines the cooler cooling start timing based on the driving state-related information and a driving mode of the vehicle. (Item 8) The refrigeration cycle device according to item 7, wherein the cooler cooling determination unit determines the target temperature of the heat medium based on the traveling mode.

[0195] Although the present disclosure is described based on embodiments, it should be understood that the present disclosure is not limited to the above-described embodiments and structures. The present disclosure also includes various modifications and variations within the scope of equivalents. In addition, various combinations and methods, and further combinations and methods that include only one element, or more or less than the above elements, also fall within the scope and concept of the present disclosure.

Claims

1. A refrigeration cycle device comprising: a heat medium circuit (30) for heat medium circulation; Power transmission equipment (35, 36), which is an electrical device for generating driving force for the vehicle, and is cooled by the heat medium; a radiator (32) for exchanging heat between the heat medium and external air; a cooler (17) for exchanging heat between the low-pressure refrigerant of the refrigeration cycle and the heat medium; a circuit switching unit (38) for switching the heat medium circuit to a first circulation state in which the heat medium circulates between the power transmission device and the radiator, or to a second circulation state in which the heat medium circulates between the power transmission device and the cooler; a circuit switching decision unit (60f) which, when it is determined that the temperature of the power transmission device exceeds a threshold value (PT) in the first circulation state, decides to switch to the second circulation state through the circuit switching unit; a cooling switching portion (16) that switches between a cooler cooling state in which the heat medium is cooled by the cooler and a cooler non-cooling state in which the heat medium is not cooled by the cooler; and A cooler cooling determination unit (60c) determines a time at which the cooling switching unit switches from the cooler non-cooling state to the cooler cooling state, i.e., a cooler cooling start time, based on information related to the driving state of the vehicle, i.e., driving state related information.

2. The refrigeration cycle device according to claim 1, wherein The cooler cooling start time is a time before the circuit switching determination unit switches from the first circulation state to the second circulation state.

3. The refrigeration cycle device according to claim 1, wherein The cooler cooling determination unit determines switching between the cooler non-cooling state and the cooler cooling state so that the temperature of the heat medium is equal to or lower than a predetermined temperature after the vehicle is started and before the cooler cooling start time.

4. The refrigeration cycle device according to any one of claims 1 to 3, characterized in that: The cooler cooling start timing is a timing at which the temperature of the power transmission device exceeds the threshold value, which is predicted based on the driving state-related information.

5. The refrigeration cycle device according to claim 4, wherein: The cooler cooling determination unit determines a target temperature of the heat medium based on a predicted temperature of the power transmission device.

6. The refrigeration cycle device according to any one of claims 1 to 3, characterized in that: The cooler cooling determination unit determines the cooler cooling start timing so that the heat medium can be cooled to a target temperature before the temperature of the power transmission device reaches the threshold value.

7. The refrigeration cycle device according to claim 1, wherein The cooler cooling determination unit determines the cooler cooling start timing based on the driving state-related information and the driving mode of the vehicle.

8. The refrigeration cycle device according to claim 7, wherein: The cooler cooling determination unit determines a target temperature of the heat medium based on the traveling mode.

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