Refrigeration cycle equipment

Abstract

This refrigeration cycle device comprises: a circuit switching unit (38) that switches a heat medium circuit (30) between a first circulation state in which a heat medium circulates between a power train device (35, 36) and a radiator (32) and a second circulation state in which the heat medium circulates between the power train device and a chiller (17); a circuit switching determination unit (60f) which, when it is determined that the temperature of the power train device exceeds a threshold value (PT) in the first circulation state, determines switching to the second circulation state by the circuit switching unit; a cooling switching unit (16) that performs switching between a chiller cooling state in which the heat medium is cooled by the chiller and a chiller non-cooling state in which the heat medium is not cooled by the chiller; and a chiller cooling determination unit (60c) that determines, on the basis of traveling state-related information that is information related to a vehicle traveling state, a chiller cooling start timing that is the timing at which the cooling switching unit performs switching from the chiller non-cooling state to the chiller cooling state.

Description

Cross-reference to Related Applications

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

Technical Field

[0002] The present disclosure relates to a refrigeration cycle device for cooling powertrain equipment.

Background Art

[0003] Conventionally, Patent Document 1 describes a vehicle refrigeration cycle device that recovers the exhaust heat of powertrain equipment such as an inverter and a motor generator and uses it for heating inside the vehicle. Powertrain equipment is an electrical device for generating the driving force of a vehicle and generates heat during operation.

[0004] In this conventional technology, a cooling water evaporator for cooling water, a low-temperature radiator, and powertrain equipment are arranged in parallel in a low-temperature cooling water circuit through which low-temperature cooling water circulates. The cooling water evaporator exchanges heat between the low-pressure refrigerant of the refrigeration cycle and the low-temperature cooling water in the low-temperature cooling water circuit, and absorbs heat from the low-temperature cooling water into the low-pressure refrigerant. The low-temperature radiator radiates heat from the low-temperature cooling water to the outside air.

[0005] In this conventional technology, it is possible to switch between a state in which low-temperature cooling water circulates between the powertrain equipment and the cooling water evaporator and a state in which low-temperature cooling water circulates between the powertrain equipment and the low-temperature radiator using a three-way valve.

[0006] In a state where low-temperature cooling water circulates between the powertrain equipment and the cooling water evaporator for cooling water, the exhaust heat of the powertrain equipment is used for heating inside the vehicle. In a state where low-temperature cooling water circulates between the powertrain equipment and the low-temperature radiator, the exhaust heat of the powertrain equipment is radiated to the outside air.

Prior Art Documents

Patent Documents

[0007] [Patent Document 1] Patent No. 6791052 [Overview of the project]

[0008] The conventional technologies described above do not take into account efficient cooling of powertrain components, thus limiting the miniaturization of powertrain components and improvements in driving performance.

[0009] In view of the above points, this disclosure aims to efficiently cool powertrain equipment.

[0010] A refrigeration cycle device according to one aspect of the present disclosure comprises a heat transfer medium circuit, powertrain equipment, a radiator, a chiller, a circuit switching unit, a circuit switching determination unit, a cooling switching unit, and a chiller cooling determination unit.

[0011] A heat transfer medium circulates within the heat transfer circuit. Powertrain equipment is electrical equipment that generates the driving force for the vehicle and is cooled by the heat transfer medium. The radiator exchanges heat between the heat transfer medium and the outside air. The chiller exchanges heat between the low-pressure refrigerant of the refrigeration cycle and the heat transfer medium.

[0012] The circuit switching unit switches the heat transfer fluid circuit between a first circulation state in which the heat transfer fluid circulates between the powertrain equipment and the radiator, and a second circulation state in which the heat transfer fluid circulates between the powertrain equipment and the chiller.

[0013] The circuit switching determination unit determines that the temperature of the powertrain equipment exceeds a threshold in the first circulation state, and decides to switch to the second circulation state. The cooling switching unit switches between a chiller-cooled state, in which the heat transfer medium is cooled by the chiller, and a chiller-uncooled state, in which the heat transfer medium is not cooled by the chiller.

[0014] The chiller cooling determination unit determines the chiller cooling start timing, which is the timing at which the cooling switching unit switches from a non-chiller cooling state to a chiller cooling state, based on driving state-related information, which is information related to the vehicle's driving state.

[0015] According to this, powertrain components can be cooled based on driving condition-related information, thus enabling efficient cooling of the powertrain components. [Brief explanation of the drawing]

[0016] The above-mentioned and other purposes, features, and benefits of this disclosure will be further clarified by the detailed description below, with reference to the attached drawings. [Figure 1] This is an overall configuration diagram showing the refrigeration cycle device of the first embodiment. [Figure 2] This is a block diagram showing the electrical control unit of the refrigeration cycle device of the first embodiment. [Figure 3] This is a configuration diagram showing the low-temperature cooling water circuit in the radiator heat dissipation mode of the refrigeration cycle device of the first embodiment. [Figure 4] This is a configuration diagram showing the low-temperature cooling water circuit in the radiator heat dissipation mode and chiller ON mode of the refrigeration cycle device of the first embodiment. [Figure 5] This is a configuration diagram showing the low-temperature cooling water circuit in the chiller cooling mode of the refrigeration cycle device of the first embodiment. [Figure 6] This flowchart shows a portion of the control processing performed by the control device of the refrigeration cycle system of the first embodiment. [Figure 7] This flowchart shows a portion of the control processing performed by the control device of the refrigeration cycle system of the first embodiment. [Figure 8] This is a time chart showing an example of control in the refrigeration cycle device of the first embodiment. [Figure 9] This flowchart shows a portion of the control processing performed by the control device of the refrigeration cycle system of the second embodiment. [Figure 10]It is a flowchart showing a part of the control process executed by the control device of the refrigeration cycle device of the third embodiment. [Figure 11] It is a time chart showing a control example in the refrigeration cycle device of the third embodiment. [Figure 12] It is a flowchart showing a part of the control process executed by the control device of the refrigeration cycle device of the fourth embodiment. [Figure 13] It is a time chart showing a control example in the refrigeration cycle device of the fourth embodiment. [Figure 14] It is a flowchart showing a part of the control process executed by the control device of the refrigeration cycle device of the fifth embodiment. [Figure 15] It is a control characteristic diagram showing a control example in the refrigeration cycle device of the fifth embodiment. [Figure 16] It is an overall configuration diagram showing the refrigeration cycle device of the sixth embodiment.

Modes for Carrying Out the Invention

[0017] Hereinafter, a plurality of modes for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to those described in the preceding embodiment may be denoted by the same reference numerals, and redundant descriptions may be omitted. When only a part of the configuration is described in each embodiment, other embodiments described previously can be applied to other parts of the configuration. Not only combinations of parts that are specifically shown to be combinable in each embodiment, but also partial combinations of embodiments are possible as long as there is no problem with the combination, even if not explicitly stated.

[0018] (First Embodiment) The embodiments will be described below with reference to the figures. The refrigeration cycle device 10 shown in Figure 1 is applied to a vehicle air conditioning system 1 installed in an electric vehicle or a hybrid vehicle. An electric vehicle is a vehicle that obtains driving force from an electric motor. A hybrid vehicle is a vehicle that obtains driving force from an engine (in other words, an internal combustion engine) and a traction electric motor.

[0019] The vehicle air conditioning system 1 is an air conditioning system with a battery temperature adjustment function. The vehicle air conditioning system 1 provides air conditioning to the vehicle interior, which is the space to be air-conditioned, and also adjusts the temperatures of the battery 33, inverter 35, and motor generator 36. Therefore, the objects to be cooled in the refrigeration cycle system 10 of this embodiment are air, battery 33, inverter 35, and motor generator 36.

[0020] Battery 33 is a secondary battery that stores power supplied to in-vehicle equipment such as electric motors. In this embodiment, battery 33 is a lithium-ion battery. 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 parallel.

[0021] The inverter 35 is a power conversion unit that converts the DC power supplied from the battery 33 into AC power and outputs it to the motor generator 36. The motor generator 36 uses the power output from the inverter 35 to generate driving force for propulsion, and also generates regenerative power during deceleration and downhill driving.

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

[0023] The objects to be cooled in the refrigeration cycle device 10 may be powertrain equipment such as a DC-DC converter or a charger. The DC-DC converter converts high-voltage DC power supplied from the battery 33 into low-voltage DC power and supplies it to auxiliary equipment mounted on the vehicle. The charger is used to charge the battery 33 using an external power source.

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

[0025] The refrigeration cycle device 10 is a vapor compression type refrigerator comprising 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 chiller 17, and a receiver 18. In the refrigeration cycle device 10 of this embodiment, a fluorocarbon refrigerant is used as the refrigerant, and a subcritical refrigeration cycle is configured in which the high-pressure side refrigerant pressure does not exceed the critical pressure of the refrigerant. The refrigerant is mixed with refrigeration oil (specifically, PAG oil) to lubricate the compressor 11. A portion of the refrigeration oil circulates in the cycle together with the refrigerant.

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

[0027] The condenser 12 is a high-pressure refrigerant heat exchanger that condenses the high-pressure refrigerant by exchanging heat between the high-pressure 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 that acts as a heat transfer medium. The cooling water in the high-temperature cooling water circuit 20 is a high-temperature heat transfer medium. In this embodiment, the cooling water in the high-temperature cooling water circuit 20 is a liquid containing at least ethylene glycol, dimethylpolysiloxane, or a nanofluid, or an antifreeze liquid. The high-temperature cooling water circuit 20 is a high-temperature heat transfer medium circuit in which the high-temperature heat transfer medium circulates.

[0029] The receiver 18 is a gas-liquid separation unit that separates the gaseous and liquid phases of the refrigerant flowing out of the condenser 12, allowing the liquid phase refrigerant to flow downstream, and also stores the excess refrigerant from the cycle. The flow of liquid phase refrigerant flowing out of the receiver 18 is branched at the branching section 10a.

[0030] The first expansion valve 13 is a first pressure reduction unit that reduces the pressure and expands the liquid phase refrigerant flowing out of the receiver 18. The first expansion valve 13 is an electrically operated variable throttling mechanism and has a valve body and an electric actuator. The valve body is configured to change the opening degree of the refrigerant flow path (in other words, the throttling opening degree). The electric actuator has a stepping motor that changes the throttling opening degree of the valve body.

[0031] The first expansion valve 13 is composed of a variable throttle mechanism with a fully closing function that completely closes the refrigerant flow path. The operation of the first expansion valve 13 is controlled by a control signal output from the control device 60 shown in Figure 2.

[0032] The first evaporator 14 is a refrigerant-air heat exchanger that cools the air supplied to the vehicle interior by evaporating the refrigerant through heat exchange between the refrigerant flowing out from the first expansion valve 13 and the air supplied to the vehicle interior. The first evaporator 14 is an air evaporator that cools the air by evaporating the refrigerant. The first evaporator 14 is the first evaporation section.

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

[0034] The constant pressure valve 15 is composed of a mechanical variable throttling mechanism. Specifically, the constant pressure valve 15 decreases the area of ​​the refrigerant flow path (i.e., throttling opening) when the refrigerant pressure at the outlet side of the first evaporator 14 falls below a predetermined value, and increases the area of ​​the refrigerant flow path (i.e., throttling opening) when the refrigerant pressure at the outlet side of the first evaporator 14 exceeds a predetermined value.

[0035] In cases where the circulating refrigerant flow rate in the cycle fluctuates little, a fixed throttle consisting of an orifice, capillary tube, etc., may be used instead of the constant pressure valve 15.

[0036] The second expansion valve 16 and chiller 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 reduction section that reduces the pressure and expands the liquid phase refrigerant flowing out of the condenser 12. The second expansion valve 16 is an electrically operated variable throttling mechanism and has a valve body and an electric actuator. The valve body is configured to change the opening degree of the refrigerant flow path (in other words, the throttling opening degree). The electric actuator has a stepping motor that changes the throttling opening degree of the valve body.

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

[0039] Chiller 17 is a second evaporator that cools the cooling water by evaporating the refrigerant through heat exchange between the low-pressure refrigerant discharged from the second expansion valve 16 and the cooling water in the low-temperature cooling water circuit 30. Chiller 17 is a low-pressure side refrigerant heat transfer medium heat exchanger. Chiller 17 is a cooling evaporator that cools the cooling water by evaporating the refrigerant. Chiller 17 is the second evaporation section.

[0040] The gaseous refrigerant evaporated in the chiller 17 merges with the refrigerant flowing out from the constant pressure valve 15 at the confluence section 10b, and is then drawn into the compressor 11 and compressed.

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

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

[0043] The high-temperature pump 21 is a heat transfer fluid pump that draws in and discharges cooling water. The high-temperature pump 21 is an electrically operated pump. The high-temperature pump 21 is a high-temperature flow rate adjustment unit that adjusts 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 supplied to the vehicle interior by exchanging heat between the cooling water in the high-temperature cooling water circuit 20 and the air supplied to the vehicle interior. In the heater core 22, the cooling water dissipates heat into the air supplied to the vehicle interior. The condenser 12, the high-temperature cooling water circuit 20, and the heater core 22 are heat dissipation units that dissipate heat into the air by exchanging heat between the refrigerant discharged from the compressor 11 and the air supplied to the vehicle interior.

[0045] The high-temperature side radiator 23 is a high-temperature heat transfer medium outside air heat exchanger that exchanges heat between the cooling water of the high-temperature cooling water 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 cooling water.

[0046] The on-off valve 24 is a solenoid valve that opens and closes the cooling water flow path on the high-temperature side radiator 23. 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 equipped with a mechanical mechanism that opens and closes the cooling water flow path by displacing the valve body with thermowax, which changes volume with temperature.

[0048] The electric heater 25 is an auxiliary heating unit that provides supplementary heating for the cooling water in the high-temperature cooling water circuit 20. The electric heater 25 is an auxiliary heat source for heating the air in the heater core 22. As the electric heater 25, a PTC heater or the like that which generates heat when power is supplied can be used. The electric heater 25 is a Joule heat generating unit 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 includes a chiller 17, a low-temperature pump 31, a low-temperature radiator 32, a battery 33, a powertrain pump 34, an inverter 35, a motor generator 36, a three-way valve 37 for the battery, a three-way valve 38 for the powertrain, and a bypass three-way valve 39.

[0050] The low-temperature pump 31 is a heat transfer fluid pump that draws in and discharges cooling water. The low-temperature pump 31 is an electrically operated pump. The low-temperature pump 31 is a low-temperature flow rate adjustment unit that adjusts the flow rate of cooling water circulating in the low-temperature cooling water circuit 30. The low-temperature radiator 32 is a low-temperature heat transfer fluid outside air heat exchanger that exchanges heat between the cooling water in the low-temperature cooling water circuit 30 and the outside air.

[0051] The battery 33 is an on-board device installed in the vehicle and is a heat-generating device that generates heat during operation. The battery 33 dissipates the waste heat generated during operation into the cooling water of the low-temperature cooling water circuit 30. In other words, the battery 33 supplies heat to the cooling water of the low-temperature cooling water circuit 30.

[0052] The powertrain pump 34 is a heat transfer fluid pump that draws in and discharges cooling water in order to circulate the cooling water to the powertrain components, namely the inverter 35 and the motor generator 36.

[0053] The low-temperature 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 three-way valve 37 for the battery, the three-way valve 38 for the powertrain, and the three-way valve 39 for the bypass are heat transfer fluid flow switching sections that switch the flow of cooling water in the low-temperature cooling water circuit 30.

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

[0055] The operation of the battery valve 37, the powertrain valve 38, and the bypass valve 39 is controlled by the control device 60.

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

[0057] The heater core 22 is located in the air passage within the air conditioning casing 51, downstream of the airflow of the first evaporator 14. The air conditioning casing 51 contains an indoor / outdoor air switching box 52 and an indoor fan 53. The indoor / outdoor air switching box 52 has an indoor / outdoor air switching door 52a. The indoor / outdoor air switching door 52a is an indoor / outdoor air switching unit that switches between introducing indoor and outdoor air into the air passage within the air conditioning casing 51. The indoor / outdoor air switching door 52a is an indoor / outdoor air adjustment unit that adjusts the ratio of indoor and outdoor air introduced into the air passage within the air conditioning casing 51.

[0058] The indoor fan 53 draws in and blows in indoor and outdoor air introduced into the air passage within the air conditioning casing 51 through the indoor / outdoor air switching box 52. The indoor / outdoor air switching door 52a and the indoor fan 53 are controlled by the control device 60.

[0059] An air mix door 54 is positioned between the first evaporator 14 and the heater core 22 in the air passage within the air conditioning casing 51. The air mix door 54 adjusts the airflow ratio between the cold air that flows into the heater core 22 and the cold air that flows through the cold air bypass passage 55, from the cold air that has passed through the first evaporator 14.

[0060] The cold air bypass passage 55 is an air passage through which the cold air that has passed through the first evaporator 14 bypasses the heater core 22.

[0061] The air mix door 54 is a revolving door having a rotating shaft rotatably supported relative to the air conditioning casing 51 and a door base plate coupled to the rotating shaft. By adjusting the opening position of the air mix door 54, the temperature of the conditioned air blown from the air conditioning casing 51 into the passenger compartment can be adjusted to a desired temperature.

[0062] The rotation axis of the air mix door 54 is driven by a servo motor. 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 airflow. 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, whose temperature has been adjusted by the air mix door 54, is blown into the passenger compartment through an outlet 56 formed in the air conditioning casing 51.

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

[0066] The controlled devices controlled by the control device 60 include the compressor 11, the first expansion valve 13, the second expansion valve 16, the high-temperature pump 21, the on-off valve 24, the electric heater 25, the low-temperature pump 31, the powertrain pump 34, the three-way valve for the battery 37, the three-way valve for the powertrain 38, the bypass three-way valve 39, the indoor / outdoor air switching door 52a, and the indoor blower 53.

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

[0068] The software and hardware that controls the high-temperature pump 21 within the control device 60 is the high-temperature heat transfer medium flow control unit. The software and hardware that controls the on-off valve 24 within the control device 60 is the on-off valve control unit.

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

[0070] Various control sensors, such as an internal air temperature sensor 61, an external air temperature sensor 62, a solar radiation 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, are connected to the input side of the control device 60.

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

[0072] The first evaporator temperature sensor 64 is a temperature detection unit that detects the temperature TE1 of the first evaporator 14 (hereinafter referred to as the first evaporator temperature). 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 detection unit that detects the temperature TE2 of the chiller 17 (hereinafter referred to as the second evaporator temperature). The second evaporator temperature sensor 65 is, for example, a refrigerant temperature sensor that detects the temperature of the refrigerant flowing through the chiller 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 chiller 17.

[0075] The battery temperature sensor 67 is a battery temperature detection unit that detects the temperature TB of the battery 33. Preferably, the battery temperature sensor 67 is composed of multiple temperature sensors that detect the temperature at multiple locations on the battery 33.

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

[0077] The various control switches include a driving mode setting switch, an air conditioning switch, and a temperature setting switch. The driving mode setting switch is used to switch the vehicle's driving mode between eco mode, normal mode, and sport mode.

[0078] Eco mode is a driving mode in which the output of the motor-generator 36 is somewhat suppressed in order to prioritize energy saving. Sport mode is a driving mode in which the output of the motor-generator 36 is not restricted and energy saving is not prioritized. Normal mode is a driving mode between Eco mode and Sport mode.

[0079] The air conditioning switch is used to set whether or not to cool the air using the indoor air conditioning unit 50. The temperature setting switch is used to set the desired temperature inside the vehicle.

[0080] A powertrain control device 70 is connected to the input and output sides of the control device 60. The powertrain control device 70 is a powertrain control unit that controls the inverter 35 and motor generator 36, which are powertrain components.

[0081] The control device 60 receives the requested output value from the motor generator 36 via the powertrain control device 70. The inverter temperature sensor 71 and the 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 powertrain equipment temperature detection unit that detects the temperature of the inverter 35. The motor generator temperature sensor 72 is a powertrain equipment temperature detection unit that detects the temperature of the motor generator 36.

[0083] The 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] A car navigation system 75 is connected to the input side of the control device 60. Map information, traffic congestion information, and other data are input to the control device 60 from the car navigation system 75.

[0085] Among the information handled by the control device 60, the requested output value of the motor generator 36, the temperature of the inverter 35, the temperature of the motor generator 36, map information, and traffic congestion information are driving state-related information. Driving state-related information is information related to the driving state of the vehicle.

[0086] Next, the operation of the above configuration will be explained. First, an overview of the operation related to air conditioning will be explained. The control device 60 determines the operating state (control signals output to the various control devices) of the various control devices connected to the control device 60 based on the target discharge temperature TAO, detection signals from the sensor group, etc.

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

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

[0089] The target temperature TEO is determined based on the target discharge temperature TAO by referring to a control map stored in the control device 60. In this embodiment, the control map is determined so that the target temperature TEO increases as the target discharge temperature TAO increases.

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

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

[0092] The refrigerant flowing out of the condenser 12 flows into the first expansion valve 13, where it is depressurized and expanded until it becomes low-pressure refrigerant. The low-pressure refrigerant, depressurized in the first expansion valve 13, flows into the first evaporator 14, where it absorbs heat from the air being blown into the vehicle cabin and evaporates. This cools the air being blown into the vehicle cabin.

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

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

[0095] As described above, the first evaporator 14 cools the air by allowing the low-pressure refrigerant to absorb heat from the air, and the cooled air is heated by the heater core 22 and blown into the vehicle interior. This makes it possible to provide air conditioning for the vehicle interior.

[0096] Next, the operation of the inverter 35 and motor generator 36 in relation to cooling will be explained. The control device 60 switches the operating mode of the refrigeration cycle device 10 to either chiller ON mode or chiller OFF mode. In chiller ON mode, the second expansion valve 16 is opened to a throttled position, so that the low-pressure refrigerant, which has been depressurized and expanded by the second expansion valve 16, flows into the chiller 17, and the cooling water of the low-temperature cooling water circuit 30 is cooled by the chiller 17. In chiller OFF mode, the second expansion valve 16 is fully closed, so no refrigerant flows into the chiller 17, and the cooling water of the low-temperature cooling water circuit 30 is not cooled by the chiller 17.

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

[0098] In radiator heat dissipation mode, the powertrain pump 34 is activated, and the powertrain three-way valve 38 is switched so that coolant circulates between the inverter 35 and motor generator 36 and the low-temperature side radiator 32, as shown by the dashed arrow in Figure 3. As a result, the heat generated by the inverter 35 and motor generator 36 is dissipated to the outside air by the low-temperature side radiator 32.

[0099] When the refrigeration cycle device 10 is in chiller ON mode during radiator heat dissipation mode, the low-temperature pump 31 is activated, and the bypass three-way valve 39 is switched so that cooling water circulates between the chiller 17 and the bypass passage 30a, as shown by the dashed arrow in Figure 4. This lowers the temperature of the cooling water circulating between the chiller 17 and the bypass passage 30a.

[0100] In chiller cooling mode, at least one of the low-temperature pump 31 and the powertrain pump 34 is activated, and the powertrain three-way valve 38 is switched so that cooling water circulates between the inverter 35 and motor generator 36 and the chiller 17, as shown by the dashed arrow in Figure 5. As a result, the waste heat from the inverter 35 and motor generator 36 is absorbed by the chiller 17 into the refrigerant of the refrigeration cycle device 10.

[0101] In chiller cooling mode, the inverter 35 and motor generator 36 are cooled using the refrigeration cycle device 10, resulting in a higher cooling capacity for the inverter 35 and motor generator 36 compared to radiator heat dissipation mode, where the heat from the inverter 35 and motor generator 36 is dissipated to the outside air.

[0102] Figure 6 is a flowchart showing the control process performed 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 trend of the motor generator 36's requested output is predicted based on map information, traffic congestion information, etc., input from the car navigation system 75. For example, it is predicted that the motor generator 36's requested output will be high when driving on roads with high speed limits, such as highways, and low when driving on congested roads.

[0104] In step S120, the temperature trends of the inverter 35 and the motor generator 36 are predicted based on the motor generator 36's requested output predicted in step S110. For example, the larger the predicted requested output of the motor generator 36, the higher the temperature of the inverter 35 and the motor generator 36 are predicted to rise.

[0105] In step S130, it is determined whether the temperatures of the inverter 35 and motor generator 36 predicted in step S110 have exceeded the threshold PT. The threshold PT is the temperature of the inverter 35 and motor generator 36 at which the cooling capacity of the inverter 35 and motor generator 36 becomes insufficient in the radiator heat dissipation mode.

[0106] If it is determined in step S130 that the predicted temperatures of the inverter 35 and motor generator 36 do not exceed the threshold PT, the process proceeds to steps S140 to S150, where the operating mode of the refrigeration cycle device 10 is set to chiller OFF mode and the circulation mode of the low-temperature cooling water circuit 30 is set to radiator heat dissipation mode. As a result, as shown in Figure 3, the waste heat from the inverter 35 and motor generator 36 is dissipated to the outside air by the low-temperature side radiator 32.

[0107] If it is determined in step S130 that the predicted temperatures of the inverter 35 and motor generator 36 exceed the threshold PT, the process proceeds to step S160, and the operating mode of the refrigeration cycle device 10 is set to chiller ON mode. As a result, the chiller 17 cools the cooling water in the low-temperature cooling water circuit 30, as shown in Figure 4.

[0108] In the following 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 the threshold PT.

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

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

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

[0112] In step S200, thermal property information of the inverter 35 and motor generator 36 is acquired. This thermal property information includes an efficiency map (i.e., a map showing the relationship between output and heat generation), an allowable upper temperature limit, and thermal resistance.

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

[0114] In step S220, the heat generated by the inverter 35 and the motor generator 36 is calculated. Specifically, the heat generated by the inverter 35 and the motor generator 36 is calculated based on the efficiency maps of the inverter 35 and the motor generator 36 obtained in step S200 and the requested output value of the motor generator 36 obtained 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 formula F2, based on the allowable upper temperature limit and thermal resistance of the inverter 35 and motor generator 36 obtained in step S200, and the amount of heat generated by the inverter 35 and motor generator 36 calculated in step S220. Target temperature = Allowable upper temperature - Heat generation × Thermal resistance…(F2) An example of control according to this embodiment is shown in Figure 8. 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 PT, the operating mode of the refrigeration cycle device 10 is set to chiller ON mode, so the cooling water temperature of the low-temperature cooling water circuit 30 decreases. The cooling water temperature of the low-temperature cooling water circuit 30 is controlled to approach the target temperature determined in step S220.

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

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

[0118] As a result, the heat generated by the inverter 35 and motor generator 36 is released into the outside air without the need for the refrigeration cycle device 10, thus saving energy in the cooling of the inverter 35 and motor generator 36.

[0119] In this embodiment, as can be seen from the description of steps S110 to S160, the control device 60 determines the chiller cooling start timing based on driving condition-related information. The chiller cooling start timing is the timing at which the operating mode of the refrigeration cycle device 10 is switched from chiller OFF mode to chiller ON mode. The driving condition-related information includes map information and traffic congestion information input from the car navigation device 75.

[0120] According to this, the inverter 35 and motor generator 36 can be cooled based on information related to the driving conditions, so the inverter 35 and motor generator 36 can be cooled efficiently.

[0121] In this embodiment, as can be seen from the description of steps S160 to S190, the timing for starting chiller cooling is the timing before switching the circulation mode of the low-temperature cooling water circuit 30 from the radiator heat dissipation mode to the chiller cooling mode.

[0122] According to this, the cooling water in the low-temperature cooling water circuit 30 is cooled in advance before the cooling of the inverter 35 and motor generator 36 is started, making it possible to cool the inverter 35 and motor generator 36 quickly.

[0123] In this embodiment, as can be seen from the description of steps S130 to S140, the chiller cooling start timing is the timing when the temperature of the inverter 35 and motor generator 36, predicted based on the driving condition-related information, exceeds the threshold PT.

[0124] According to this method, the timing for starting chiller cooling is determined by predicting the temperatures of the inverter 35 and motor generator 36. This allows for faster cooling of the inverter 35 and motor generator 36 compared to when the timing for starting chiller cooling is determined based on the actual temperatures of the inverter 35 and motor generator 36.

[0125] In this embodiment, as can be seen 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 motor generator 36.

[0126] According to this method, the cooling water can be cooled to the target temperature more quickly compared to when the target temperature of the cooling water is determined based on the actual temperatures of the inverter 35 and the motor generator 36.

[0127] (Second Embodiment) In the above embodiment, if it is determined that the predicted temperatures of the inverter 35 and motor generator 36 exceed the threshold PT, the operating mode of the refrigeration cycle device 10 is set to chiller ON mode.

[0128] In contrast, in this embodiment, the time at which the temperatures of the inverter 35 and motor generator 36 reach a threshold PT is predicted, and the operating mode of the refrigeration cycle device 10 is set to chiller ON mode so that the cooling water is cooled to the target temperature by that time.

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

[0130] In the subsequent step S135, based on the requested output of the motor generator 36 predicted in step S110, the temperature trends of the inverter 35 and the motor generator 36 are predicted, and the time at which the temperatures of the inverter 35 and the motor generator 36 reach the threshold PT (hereinafter referred to as the arrival time) is also predicted.

[0131] In step S136, the time at which the operating mode of the refrigeration cycle device 10 is switched to the chiller ON mode (hereinafter referred to as the switching time) is determined. The switching time is the time that is set back from the arrival time by the amount of time required to cool the cooling water to the target temperature. Therefore, if the operating mode of the refrigeration cycle device 10 is switched to the chiller ON mode at the switching time, the cooling water will be cooled to the target temperature by 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 operating mode of the refrigeration cycle device 10 is set to chiller OFF mode and the circulation mode of the low-temperature cooling water circuit 30 is set to radiator heat dissipation mode. As a result, as shown in Figure 3, the waste heat from the inverter 35 and motor generator 36 is dissipated to the outside air by the low-temperature side radiator 32.

[0133] If it is determined in step S137 that the current time has reached the switching time, the process proceeds to step S160, and the operating mode of the refrigeration cycle device 10 is set to chiller ON mode. As a result, the cooling water in the low-temperature cooling water circuit 30 is cooled by the chiller 17, as shown in Figure 4. Steps S170 to S190 are the same as in the first embodiment described above.

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

[0135] According to this, when the temperature of the inverter 35 and motor generator 36 reaches the threshold PT, it becomes possible to immediately supply cooling water at the target temperature to the inverter 35 and motor generator 36, thereby enabling rapid cooling of the inverter 35 and motor generator 36.

[0136] (Third embodiment) In the first embodiment described above, as explained in steps S130 to S160, when it is determined that the predicted temperature of the inverter 35 and the motor generator 36 exceeds the threshold PT (in other words, when a cooling request for the cooling water is issued), the operating mode of the refrigeration cycle device 10 is set to chiller ON mode and the chiller 17 cools the cooling water in the low-temperature cooling water circuit 30 so that it approaches the target temperature.

[0137] In contrast, in this embodiment, before the operating mode of the refrigeration cycle device 10 is set to chiller ON mode in step S160 of the above embodiment (in other words, before there is a cooling request for the cooling water, for example when the vehicle is started), the cooling water in the low-temperature cooling water circuit 30 is cooled to a predetermined temperature or lower by the chiller 17. The predetermined temperature is higher than the target temperature and lower than the ambient temperature.

[0138] Figure 10 is a flowchart showing the control process performed by the control device 60 in this embodiment. The control process shown in this flowchart is performed before the operating mode of the refrigeration cycle device 10 is set to chiller ON mode in step S160 of the above embodiment (i.e., when there is no cooling request from the chiller 17).

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

[0140] If it is determined in step S300 that the cooling water temperature of the low-temperature cooling water circuit 30 is not above a predetermined temperature, the process proceeds to step S310, where it is determined whether or not the cooling water temperature of the low-temperature cooling water circuit 30 is below 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 below the target temperature, the process proceeds to step S320, and the operating mode of the refrigeration cycle device 10 is set to chiller OFF mode. In other words, since there is no need to further cool the cooling water temperature in the low-temperature cooling water circuit 30, the chiller 17 does not cool the cooling water in the low-temperature cooling water circuit 30.

[0142] If it is determined in step S300 that the cooling water temperature of the low-temperature cooling water circuit 30 is above a predetermined temperature, and if it is determined in step S310 that the cooling water temperature of the low-temperature cooling water circuit 30 is not below the target temperature, the process proceeds to step S330, and the operating mode of the refrigeration cycle device 10 is set to chiller ON mode. As a result, the chiller 17 maintains the cooling water temperature of the low-temperature cooling water circuit 30 at or above the target temperature and below the predetermined temperature.

[0143] An example of control according to this embodiment is shown in Figure 11. In this control example, when the vehicle starts up, the coolant temperature in the low-temperature coolant circuit 30 is approximately the same as the ambient temperature and above a predetermined temperature, so the operating mode of the refrigeration cycle device 10 is set to chiller ON mode. As a result, the coolant in the low-temperature coolant circuit 30 is cooled by the chiller 17, and the temperature of the coolant decreases.

[0144] When the temperature of the cooling water in the low-temperature cooling water circuit 30 falls below the target temperature, the operating mode of the refrigeration cycle device 10 is switched to chiller OFF mode. As a result, the cooling water in the low-temperature cooling water circuit 30 is no longer cooled by the chiller 17, causing the temperature of the cooling water to rise.

[0145] When the cooling water temperature in the low-temperature cooling water circuit 30 exceeds a predetermined temperature, the operating mode of the refrigeration cycle device 10 is switched to chiller ON mode. As a result, the cooling water in the low-temperature cooling water circuit 30 is cooled by the chiller 17, causing the temperature of the cooling water to decrease.

[0146] By repeatedly switching between chiller ON mode and chiller OFF mode, the cooling water temperature in the low-temperature cooling water circuit 30 is maintained between the target temperature and a predetermined temperature. Then, in step S160 of the above embodiment, when the operating mode of the refrigeration cycle device 10 is set to chiller ON mode (in other words, when there is a cooling request for the cooling water), the switching between chiller ON mode and chiller OFF mode ends and the chiller ON mode continues.

[0147] In this case, the cooling water temperature in the low-temperature cooling water circuit 30 is not approximately the same as the ambient temperature, but is cooled to a temperature between the target temperature and a predetermined temperature. Therefore, the cooling water temperature in the low-temperature cooling water circuit 30 can be quickly brought up to the target temperature.

[0148] When the temperature of the cooling water in the low-temperature cooling water circuit 30 falls below the target temperature, the operating mode of the refrigeration cycle device 10 is set to chiller OFF mode, and the low-temperature pump 31 is stopped to stop the circulation of the cooling water in the low-temperature cooling water circuit 30, thereby suppressing the rise in the temperature of the cooling water in the low-temperature cooling water circuit 30.

[0149] In this embodiment, the control device 60 decides to switch between chiller ON mode and chiller OFF mode after the vehicle has started and before the chiller cooling start timing, so that the temperature of the coolant in the low-temperature coolant circuit 30 falls below a predetermined temperature.

[0150] According to this, since the cooling water is cooled in advance after the vehicle starts up, the inverter 35 and motor generator 36 can be cooled more quickly.

[0151] In this embodiment, the cooling of the coolant in the low-temperature coolant circuit 30 is started when the vehicle is started, but the 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 the occupants get into the vehicle.

[0152] (Fourth Embodiment) In the third embodiment described above, before the operating mode of the refrigeration cycle device 10 is set to chiller ON mode in step S160 of the above embodiment (i.e., before forced cooling of the inverter 35 and motor generator 36 becomes necessary), the cooling water of the low-temperature cooling water circuit 30 is cooled in advance by the chiller 17 to a target temperature or higher and a predetermined temperature or lower.

[0153] In this embodiment, the cooling water in the low-temperature cooling water circuit 30 is cooled in the chiller 17 to a temperature range lower than the ambient temperature before forced cooling of the inverter 35 and motor generator 36 becomes necessary.

[0154] Specifically, the cooling water in the low-temperature cooling water circuit 30 is cooled by the chiller 17 so that the difference from the ambient temperature is within the range of a first temperature difference α1 or more and a second temperature difference α2 or less. The second temperature difference α2 is a value smaller than the temperature difference between the ambient temperature and the target temperature. The first temperature difference α1 is a value smaller than the temperature difference between the ambient temperature and the target temperature and larger than the second temperature difference α2.

[0155] Figure 12 is a flowchart showing the control process performed by the control device 60 in this embodiment. The control process shown in this flowchart is performed before the operating mode of the refrigeration cycle device 10 is set to chiller ON mode in step S160 of the above embodiment (i.e., when there is no cooling request from the chiller 17).

[0156] In step S400, it is determined whether forced cooling of the inverter 35 and motor generator 36 is necessary. For example, if the temperature of the inverter 35 and the motor generator 36 exceed the threshold PT, it is determined that forced cooling of the inverter 35 and motor generator 36 is necessary.

[0157] If it is determined in step S400 that forced cooling of the inverter 35 and motor generator 36 is not necessary, the process proceeds to step S410, where it is determined whether the cooling water temperature of the low-temperature cooling water circuit 30 is above the ambient temperature - 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 is not above the ambient temperature - second temperature difference α2, the process proceeds to step S420, where it is determined whether or not the cooling water temperature of the low-temperature cooling water circuit 30 is below the ambient temperature - first temperature difference α1.

[0159] If it is determined in step S420 that the cooling water temperature of the low-temperature cooling water circuit 30 is below the ambient temperature - first temperature difference α1, the process proceeds to step S430, and the operating mode of the refrigeration cycle device 10 is set to chiller OFF mode.

[0160] If, in step S410, it is determined that the cooling water temperature of the low-temperature cooling water circuit 30 is above the ambient temperature - second temperature difference α2, and if, in step S420, it is determined that the cooling water temperature of the low-temperature cooling water circuit 30 is not below the ambient temperature - first temperature difference α1, the process proceeds to step S440, and the operating mode of the refrigeration cycle device 10 is set to chiller ON mode.

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

[0162] An example of control according to this embodiment is shown in Figure 13. In this control example, when the vehicle starts up, the coolant temperature in the low-temperature coolant circuit 30 is approximately the same as the ambient temperature and exceeds the ambient temperature-second temperature difference α2, so the operating mode of the refrigeration cycle device 10 is set to chiller ON mode. As a result, the coolant in the low-temperature coolant circuit 30 is cooled by the chiller 17, and the temperature of the coolant decreases.

[0163] When the temperature of the cooling water in the low-temperature cooling water circuit 30 falls below the ambient temperature - first temperature difference α1, the operating mode of the refrigeration cycle device 10 is set to chiller OFF mode. As a result, the cooling water in the low-temperature cooling water circuit 30 is no longer cooled by the chiller 17, and the temperature of the cooling water rises.

[0164] When the cooling water temperature in the low-temperature cooling water circuit 30 exceeds the ambient temperature - second temperature difference α2, the operating mode of the refrigeration cycle device 10 is switched to chiller ON mode. As a result, the cooling water in the low-temperature cooling water circuit 30 is cooled by the chiller 17, causing the cooling water temperature to decrease.

[0165] By repeatedly switching between chiller ON mode and chiller OFF mode, the cooling water temperature in the low-temperature cooling water circuit 30 is maintained between the ambient temperature - first temperature difference α1 and the ambient temperature - second temperature difference α2. Then, in step S160 of the above embodiment, when the operating mode of the refrigeration cycle device 10 is set to chiller ON mode, the switching between chiller ON mode and chiller OFF mode ends and the chiller ON mode continues. At this time, since the cooling water temperature in the low-temperature cooling water circuit 30 is not approximately the same as the ambient temperature but is between the ambient temperature - first temperature difference α1 and the ambient temperature - second temperature difference α2, the cooling water temperature in the low-temperature cooling water circuit 30 can be quickly brought to the target temperature.

[0166] According to this embodiment, when cooling the cooling water of the low-temperature cooling water circuit 30 in advance before forced cooling of the inverter 35 and motor generator 36 becomes necessary, a constant temperature difference with respect to the ambient temperature can be ensured. In other words, since the cooling water of the low-temperature cooling water circuit 30 is maintained in a temperature range higher than the target temperature, energy savings can be achieved compared to the third embodiment described above, in which the cooling water of the low-temperature cooling water circuit 30 is cooled to the target temperature before forced cooling of the inverter 35 and motor generator 36 becomes necessary.

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

[0168] Figure 14 is a flowchart showing the control process performed 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 or not the driving mode is eco mode.

[0169] If it is determined in step S510 that the driving mode is eco mode, the process proceeds to step S520, and the target temperature of the coolant in the low-temperature coolant circuit 30 is set to the eco mode temperature LT3.

[0170] If it is determined in step S510 that the driving mode is not eco mode, the process proceeds to step S530, where it is determined whether the driving mode is sport mode. If it is determined in step S530 that the driving mode is sport mode, the process proceeds to step S540, where the target temperature of the coolant in the low-temperature coolant circuit 30 is set to sport mode temperature LT1. Sport mode temperature LT1 is lower than eco mode temperature LT3.

[0171] If it is determined in step S530 that the driving mode is not sport mode (i.e., the driving mode is normal mode), the process proceeds to step S550, and the target temperature of the coolant in the low-temperature coolant 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 eco mode temperature LT3.

[0172] By performing this control process, as shown in Figure 15, the temperature of the coolant in the low-temperature coolant circuit 30 becomes the sport mode temperature LT1 in sport mode, the normal mode temperature LT2 which is higher than the sport mode temperature LT1 in normal mode, and the eco mode temperature LT3 which is higher than the normal mode temperature LT2 in eco mode.

[0173] Therefore, in sport mode, the cooling capacity of the inverter 35 and motor generator 36 can be increased, allowing the motor generator 36 to operate at high output, while in eco mode, the cooling capacity of the inverter 35 and motor generator 36 can be reduced to save energy.

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

[0175] According to this, the coolant in the low-temperature coolant circuit 30 can be cooled at a timing that matches the vehicle's driving mode. Furthermore, the coolant can be cooled to a temperature that matches the vehicle's driving mode. As a result, the inverter 35 and motor generator 36 can be appropriately cooled according to the vehicle's driving mode.

[0176] In this embodiment, the target temperature of the coolant is determined according to three driving modes: eco mode, normal mode, and sport mode. However, the target temperature of the coolant may also be determined according to two driving modes: eco mode and sport mode.

[0177] In this embodiment, as described in steps S520 to S530, if the vehicle's driving mode is determined to be eco mode, the target temperature of the coolant in the low-temperature coolant circuit 30 is set to the eco mode temperature LT3. However, if the vehicle's driving mode is determined to be eco mode, the target temperature of the coolant in the low-temperature coolant circuit 30 is not set, and the coolant temperature of the low-temperature coolant circuit 30 may be left to chance.

[0178] Furthermore, if the vehicle's driving mode is determined to be eco mode, the target temperature of the coolant in the low-temperature coolant circuit 30 may be set to the target temperature for battery cooling if cooling of the battery 33 is necessary, or the target temperature of the coolant in the low-temperature coolant circuit 30 may be set to the same temperature as the ambient temperature if cooling of the battery 33 is not necessary. When the target temperature of the coolant in the low-temperature coolant circuit 30 is set to the same temperature as the ambient temperature, the coolant in the low-temperature coolant circuit 30 will be cooled by the chiller 17 and the heat will be 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 blown into the vehicle interior is cooled by the first evaporator 14. However, in this embodiment, as shown in Figure 16, 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 of the low-temperature cooling water circuit 30.

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

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

[0182] The low-temperature cooling water circuit 30 includes a cooler core 45 and a three-way valve 46 for the cooler core. The cooler core 45 is a heat transfer air heat exchanger that cools the air by exchanging heat between the cooling water cooled by the chiller 17 and the air blown into the passenger compartment. The three-way valve 46 for the cooler core switches the flow of cooling water to the cooler core 45. The operation of the three-way valve 46 for the cooler core is controlled by the control device 60.

[0183] In this embodiment as well, by applying the control described above, the same effects and advantages as in the above embodiment can be achieved.

[0184] This disclosure is not limited to the embodiments described above, and can be modified in various ways without departing from the spirit of this disclosure, as follows.

[0185] In the above embodiment, cooling water is used as the heat transfer medium, but various other media such as oil may be used as the heat transfer medium. Nanofluids may also be used as the heat transfer medium. A nanofluid is a fluid containing nanoparticles with a particle size on the order of nanometers.

[0186] In the refrigeration cycle device 10 of the above embodiment, a fluorocarbon refrigerant is used as the refrigerant, but the type of refrigerant is not limited to this, and natural refrigerants such as carbon dioxide or hydrocarbon refrigerants may also be used.

[0187] Furthermore, although the refrigeration cycle device 10 in 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, it 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 separate radiators, but the high-temperature side radiator 23 and the low-temperature side radiator 32 may be composed of a single radiator.

[0189] For example, the tanks of the high-temperature side radiator 23 and the low-temperature side radiator 32 may be integrated with each other, so that the high-temperature side radiator 23 and the low-temperature side radiator 32 are composed of a single radiator.

[0190] In the above embodiment, the second expansion valve 16 is configured as an integral part of a pressure reducing section that reduces the pressure of the refrigerant and a shut-off section that completely closes the refrigerant flow path to block the flow of the refrigerant. However, the shut-off section that blocks the flow of the refrigerant may be a separate component from the second expansion valve 16.

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

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

[0193] In the above embodiment, the refrigeration cycle device 10 is a receiver cycle having a receiver 18, but the refrigeration cycle device 10 may also be an accumulator cycle having an accumulator.

[0194] The features of the refrigeration cycle apparatus disclosed herein are as follows: (Item 1) A heat transfer medium circuit (30) in which the heat transfer medium circulates, Electrical equipment for generating the driving force of the vehicle, powertrain equipment (35, 36) which is cooled by the heat transfer medium, A radiator (32) that exchanges heat between the heat transfer medium and the outside air, A chiller (17) that exchanges heat between the low-pressure refrigerant of the refrigeration cycle and the heat transfer medium, The heat transfer medium circuit is switched by a circuit switching unit (38) that switches between a first circulation state in which the heat transfer medium circulates between the powertrain equipment and the radiator, and a second circulation state in which the heat transfer medium circulates between the powertrain equipment and the chiller. A circuit switching determination unit (60f) determines that if the temperature of the powertrain equipment is determined to exceed a threshold (PT) in the first circulation state, the circuit switching unit determines to switch to the second circulation state, A cooling switching unit (16) that switches between a chiller-cooled state in which the heat transfer medium is cooled by the chiller and a chiller-uncooled state in which the heat transfer medium is not cooled by the chiller, A refrigeration cycle device comprising a chiller cooling determination unit (60c) that determines the chiller cooling start timing, which is the timing at which the cooling switching unit switches from the chiller non-cooled state to the chiller cooled state, based on driving state-related information, which is information related to the driving state of the vehicle. (Item 2) The chiller cooling start timing is the timing before the circuit switching determination unit switches from the first circulation state to the second circulation state, as described in item 1. (Item 3) The chiller cooling determination unit determines, after the vehicle has started and before the chiller cooling start timing, whether to switch between the chiller non-cooled state and the chiller cooled state so that the temperature of the heat transfer medium falls below a predetermined temperature. This is the refrigeration cycle device according to item 1 or 2. (Item 4) The chiller cooling start timing is the timing at which the temperature of the powertrain equipment predicted based on the driving condition-related information exceeds the threshold, according to any one of items 1 to 3 of the refrigeration cycle device. (Item 5) The chiller cooling determination unit determines the target temperature of the heat transfer medium based on the predicted temperature of the powertrain equipment, according to the refrigeration cycle apparatus described in item 4. (Item 6) The chiller cooling determination unit determines the chiller cooling start timing so that the heat transfer medium is cooled to a target temperature before the temperature of the powertrain equipment reaches the threshold, according to any one of items 1 to 3 of the refrigeration cycle apparatus. (Item 7) The chiller cooling determination unit determines the chiller cooling start timing based on the driving state-related information and the vehicle's driving mode, according to item 1 of the refrigeration cycle device. (Item 8) The chiller cooling determination unit determines the target temperature of the heat transfer medium based on the driving mode, as described in item 7 of the refrigeration cycle apparatus.

[0195] This disclosure is described in accordance with the embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the equivalence. In addition, various combinations and forms, as well as other combinations and forms that include only one, more, or fewer of those elements, fall within the scope and concept of this disclosure.

Claims

1. A heat transfer medium circuit (30) in which the heat transfer medium circulates, Electrical equipment for generating the driving force of the vehicle, powertrain equipment (35, 36) which is cooled by the heat transfer medium, A radiator (32) that exchanges heat between the heat transfer medium and the outside air, A chiller (17) that exchanges heat between the low-pressure refrigerant of the refrigeration cycle and the heat transfer medium, The heat transfer medium circuit is switched by a circuit switching unit (38) that switches between a first circulation state in which the heat transfer medium circulates between the powertrain equipment and the radiator, and a second circulation state in which the heat transfer medium circulates between the powertrain equipment and the chiller. A circuit switching determination unit (60f) determines that if the temperature of the powertrain equipment exceeds a threshold (PT) in the first circulation state, the circuit switching unit decides to switch to the second circulation state, A cooling switching unit (16) that switches between a chiller-cooled state in which the heat transfer medium is cooled by the chiller and a chiller-uncooled state in which the heat transfer medium is not cooled by the chiller, A refrigeration cycle device comprising a chiller cooling determination unit (60c) that determines the chiller cooling start timing, which is the timing at which the cooling switching unit switches from the chiller non-cooled state to the chiller cooled state, based on driving state-related information, which is information related to the driving state of the vehicle.

2. The refrigeration cycle apparatus according to claim 1, wherein the chiller cooling start timing is the timing before the circuit switching determination unit switches from the first circulation state to the second circulation state.

3. The refrigeration cycle apparatus according to claim 1, wherein the chiller cooling determination unit determines, after the vehicle has started and before the chiller cooling start timing, to switch between the chiller non-cooled state and the chiller cooled state such that the temperature of the heat transfer medium falls below a predetermined temperature.

4. The refrigeration cycle apparatus according to any one of claims 1 to 3, wherein the chiller cooling start timing is the timing at which the temperature of the powertrain equipment predicted based on the driving condition-related information exceeds the threshold.

5. The refrigeration cycle apparatus according to claim 4, wherein the chiller cooling determination unit determines a target temperature of the heat transfer medium based on the predicted temperature of the powertrain equipment.

6. The chiller cooling start timing according to any one of claims 1 to 3, wherein the chiller cooling determination unit determines the chiller cooling start timing so that the heat transfer medium can be cooled to a target temperature before the temperature of the powertrain equipment reaches the threshold.

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

8. The refrigeration cycle apparatus according to claim 7, wherein the chiller cooling determination unit determines the target temperature of the heat transfer medium based on the driving mode.

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