Temperature control system and temperature control method for vehicle

Abstract

The invention provides a temperature control system and a temperature control method for a vehicle, which can ensure the heating capability even if the external air temperature is low and a heat source is difficult to ensure. The temperature control system includes a refrigerant circuit and a heat medium circuit. The heat medium loop includes a high-pressure side heat exchanger, a low-pressure side heat exchanger, a pump, an outdoor heat exchanger, a temperature control device, and an outdoor heat exchanger bypass path. The control device is configured to adjust the flow rate of the heat medium flowing through the low-pressure-side heat exchanger in a compressor heat source mode in which the heat medium flowing out of the high-pressure-side heat exchanger flows into the low-pressure-side heat exchanger through the temperature control device and then flows into the high-pressure-side heat exchanger through the outdoor heat exchanger bypass path. The low pressure of the refrigerant circuit is controlled to 0.2 MPa or more and 1.2 MPa or less.

Description

Technical Field

[0001] The invention relates to a temperature control system assembled on a vehicle and a temperature control method using the temperature control system. Background Art

[0002] In electric vehicles and hybrid vehicles that obtain driving force from engines and motors, when the heat source is easily insufficient, in addition to the air conditioning functions required by the vehicle, such as heating and cooling, dehumidification, and ventilation, thermal management and waste heat utilization of on-board equipment such as batteries are required. In response to such requirements, in addition to heat pump systems, multiple systems have been used, such as systems that include a cooler for cooling the battery and a heater for heating the battery, or systems that use a pump to transport water heated by waste heat from a radiator to a temperature control target.

[0003] As a vehicle thermal management system that can integrate the thermal management of air conditioning and equipment, a system has been proposed, which includes: a primary circuit in which the refrigerant circulates according to a refrigeration cycle; and a secondary circuit in which a heat medium (water, etc.) that performs heat exchange with the refrigerant in the primary circuit is transported to the vehicle-mounted equipment by a pump (for example, Patent Document 1).

[0004] The thermal management system described in Patent Document 1 includes: a first heating medium circuit, which is provided with an evaporator of a refrigerant circuit and a heating medium external air heat exchanger; and a second heating medium circuit, which is provided with a condenser of a refrigerant circuit and a heater core of a machine room air conditioning unit. The first heating medium circuit and the second heating medium circuit are switched between a non-connected state (non-connected mode) and a connected state (connected mode) assuming a low external air temperature by switching the flow paths of the first switching mechanism and the second switching mechanism.

[0005] In the non-connected mode, the heat pump operates to extract the heat of the outside air to the heat medium of the second heat medium circuit. In the connected mode, the heat medium flowing out of the evaporator does not flow into the heat medium outside air heat exchanger, but merges with the heat medium flowing out of the condenser, so that the heat medium flows into the evaporator and the condenser in parallel. At this time, the first heat medium circuit and the second heat medium circuit are connected via the evaporator and the condenser. Previous technical literature Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6083304 Summary of the invention Technical issues to be solved by the invention

[0007] In the connection mode of Patent Document 1, the heating medium flows into the evaporator and the condenser in parallel, and the heating medium flowing out of the evaporator is mixed with the heating medium flowing out of the condenser, so as to become an intermediate temperature of the temperatures of the respective heating mediums before mixing, and flows into the evaporator and the condenser. Therefore, compared with the non-connection mode, it takes time for the temperature of the heating medium flowing out of the condenser to rise. In addition, since the flow rate of the heating medium flowing into the indoor heat exchanger is reduced, there is room for improvement in heating capacity.

[0008] An object of the present invention is to provide a temperature control system and a temperature control method for a vehicle, which can ensure heating capacity even when it is difficult to ensure a heat source due to low outside air temperature. Means for solving technical problems

[0009] The present invention is a vehicle temperature control system, which comprises: A refrigerant circuit includes a compressor, a high-pressure side heat exchanger, a pressure reducing unit, and a low-pressure side heat exchanger, and is configured so that the refrigerant can circulate according to a refrigeration cycle; and a heat medium circuit configured to circulate a heat medium for exchanging heat with the refrigerant; and The control device is configured to be able to control the pressure of the refrigerant in the refrigerant circuit. The heat carrier circuit includes: a high-pressure side heat exchanger, which allows the refrigerant to exchange heat with the heat carrier; a low-pressure side heat exchanger, which allows the refrigerant to exchange heat with the heat carrier; a pump, which is configured to pressurize the heat carrier; an outdoor heat exchanger, which allows the external air to exchange heat with the heat carrier; a temperature control device, which is equivalent to a temperature control object heated or cooled by the heat carrier, or is used to heat or cool the temperature control object; and an outdoor heat exchanger bypass path, which allows the heat carrier to bypass the outdoor heat exchanger. The control device is constructed so that, in a compressor heat source mode in which the heat carrier flowing out of the high-pressure side heat exchanger flows into the low-pressure side heat exchanger via the temperature control device and then flows into the high-pressure side heat exchanger via the outdoor heat exchanger bypass path, the low pressure of the refrigerant circuit is controlled to be above 0.2MPa and below 1.2MPa by adjusting the flow rate of the heat carrier flowing in the low-pressure side heat exchanger.

[0010] Furthermore, the present invention can also be extended to a temperature control method for a vehicle. Effects of the Invention

[0011] Based on the low pressure-compressor dynamic characteristics in the compressor heat source mode, the low pressure of the refrigerant circuit is controlled to be above 0.2MPa and below 1.2MPa. Thus, even when the external air temperature is significantly lower than 0°C, the heating capacity can be ensured by the compressor heat source mode.

[0012] In the compressor heat source mode, since the high-pressure side heat exchanger and the low-pressure side heat exchanger are connected in series, the temperature of the heat medium flowing out of the high-pressure side heat exchanger can be increased more quickly than when the heat medium flows into the high-pressure side heat exchanger and the low-pressure side heat exchanger in parallel. In addition, since the circulation amount of the heat medium in the temperature control device is large, the heat exchange amount between the heat medium and the temperature control object becomes larger. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 1 is a circuit diagram (heat pump mode) showing a vehicle temperature control system according to an embodiment of the present invention. Figure 2 It is shown Figure 1 A diagram showing the system operating in heater mode. Figure 3 (a) is a block diagram showing the hardware configuration of the control device. Figure 3 (b) is a block diagram showing modules of a computer program for controlling the device. Figure 4 is a schematic diagram of a pH diagram for low outside air temperatures. Figure 5 This is a graph showing the relationship between the low pressure of the refrigerant circuit and the compressor power in the heater mode (low pressure-compressor power characteristics). Figure 6 1 is a circuit diagram showing a vehicle temperature control system according to a fifth modified example of the present invention (start-up heater mode). DETAILED DESCRIPTION

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. [Implementation Method] Figure 1 The vehicle temperature control system 1 shown is installed in, for example, a vehicle not shown in the figure, such as an electric vehicle that does not have an engine but obtains the driving force for the vehicle from an electric motor for driving, or a so-called hybrid vehicle that obtains the driving force for the vehicle from an engine and an electric motor. In addition to the air conditioning functions such as heating and cooling, dehumidification, and ventilation of the cabin 8 where passengers sit, the temperature control system 1 is also responsible for thermal management and waste heat recovery of vehicle-mounted devices such as a battery device (power supply device), a driving motor, and heat-generating electronic devices installed in the vehicle. The act of adjusting to an appropriate temperature or humidity, or managing the vehicle-mounted devices to an appropriate temperature is generally referred to as "thermal management." The vehicle temperature control system 1 and other electric devices or electronic devices provided in the vehicle-mounted devices are supplied with electric power stored in the vehicle-mounted battery device. The vehicle-mounted battery device is charged from an external power supply when the vehicle is stopped.

[0015] 〔Overall structure〕 The temperature control system 1 comprises: a refrigerant circuit 10, which is configured to allow the refrigerant to circulate; a heat medium circuit 20, which is configured to allow the heat medium that performs heat exchange with the refrigerant to circulate; and a control device 5, which sets the temperature control system 1 to a specified operating mode and controls the operating state of the temperature control system 1 according to the operating mode. In addition, the temperature control system 1 includes sensors such as an external air temperature sensor 61 for detecting the external air temperature, a temperature sensor 62 for detecting the temperature of the air-conditioned air blown to the machine room 8, a low-pressure pressure sensor 63 for detecting the low pressure pL of the refrigerant circuit 10, and a high-pressure pressure sensor 64 for detecting the high pressure pH of the refrigerant circuit 10.

[0016] The temperature control system 1 has a plurality of operation modes selected by the occupant or the control device 5. The temperature control system 1 has a heater mode HT ( Figure 2 ) is characterized in that the refrigerant pressure in the temperature control system 1 is controlled. In addition to the heater mode HT, the heat pump mode HP ( Figure 1 ). Heater mode HT is suitable when the outside air temperature is lower than heat pump mode HP.

[0017] 〔Refrigerant circuit structure〕 like Figure 1 As shown in an example of the configuration in FIG. 1 , the refrigerant circuit 10 includes a compressor 11, a condenser 12, an expansion valve 13, and an evaporator 14. In the refrigerant circuit 10, the refrigerant circulates according to a refrigeration cycle. As the refrigerant sealed in the refrigerant circuit 10, a known appropriate single refrigerant or mixed refrigerant can be used. For example, as the refrigerant of this embodiment, HFO (Hydro FluoroOlefin: hydrofluoroolefin) refrigerants such as R1234ze and R1234yf or hydrocarbon (HC: Hydrocarbon) refrigerants such as propane and isobutane can be used. In particular, R1234yf or propane is preferably used. When the above-mentioned fluorine-based or hydrocarbon-based refrigerants are used, a subcritical refrigeration cycle is constructed in which the refrigerant pressure on the high-pressure side does not exceed the critical pressure of the refrigerant.

[0018] The compressor 11 corresponds to an electric compressor including a motor driven by electric power supplied from a battery device (not shown). The compressor 11 adiabatically compresses the refrigerant sucked into a casing (not shown) by a compression mechanism and discharges the refrigerant. As the compressor 11, for example, a positive displacement compressor is preferably used, especially a compressor having a compression mechanism such as a rotary, scroll, or screw type that is rotationally driven by the output torque of a motor. In addition, as the compressor 11, a centrifugal compressor having an impeller or a compressor that reciprocates a piston within a stroke can also be used.

[0019] Lubricating oil is sealed in the housing of the compressor 11. The compressor 11 is lubricated by circulating the refrigerant containing the mist-like lubricating oil in the sliding part. The lubricating oil circulates in the refrigerant circuit 10 together with the refrigerant. In order to reliably return the lubricating oil circulating in the refrigerant circuit 10 to the compressor 11, the rotation speed of the compressor 11 is maintained at a predetermined value or above.

[0020] The condenser 12 exchanges heat between the refrigerant gas discharged from the compressor 11 and a heating medium. The expansion valve 13 (decompression unit) adiabatically expands the refrigerant flowing out of the condenser 12 by decompressing the refrigerant. As the expansion valve 13, a temperature-type expansion valve can be used in addition to an electronic expansion valve whose opening can be controlled based on a command from the control device 5. Alternatively, a capillary tube can be used instead of the expansion valve 13.

[0021] The evaporator 14 exchanges heat between the refrigerant flowing out of the expansion valve 13 and a heating medium. The refrigerant evaporated by the evaporator 14 is sucked into the compressor 11. An accumulator (gas-liquid separator) (not shown) may be provided between the evaporator 14 and the compressor 11 .

[0022] A relatively high refrigerant pressure (high pressure pH) is applied to the condenser 12, and a relatively low refrigerant pressure (low pressure pL) is applied to the evaporator 14. The refrigerant circulates in the refrigerant circuit 10 according to the pressure difference between the high pressure pH and the low pressure pL. exist Figure 1 In FIG. 1 , the flow of the refrigerant on the low-pressure side is indicated by a thick solid line, and the flow of the refrigerant on the high-pressure side is indicated by a thick dotted line. Figure 2 Same.

[0023] 〔Structure of the heat carrier circuit〕 The heating medium circuit 20 is configured to circulate a heating medium capable of exchanging heat with the refrigerant through the condenser 12 and the evaporator 14. The heating medium is used to cool or heat at least one temperature control object. One of the temperature control objects in this embodiment corresponds to the air in the machine room 8. The heating medium sealed in the heating medium circuit 20 is a liquid such as water or salt water that is maintained in a liquid phase and circulated in the heating medium circuit 20. Examples of the salt water include a mixed liquid of water and propylene glycol or a mixed liquid of water and ethylene glycol.

[0024] like Figure 1 As shown in an example of the structure, the heat medium circuit 20 includes a condenser 12, an evaporator 14, a first pump 21 and a second pump 22, an outdoor heat exchanger 23, an outdoor heat exchanger bypass path 24, an indoor heat exchanger 25, and a first switching valve 31, a second switching valve 32 and a third switching valve 33 as multiple flow path switching valves.

[0025] In this embodiment, the first switching valve 31 and the second switching valve 32 are four-way valves, and the third switching valve 33 is equivalent to a three-way valve. Figure 1 In the heat pump mode HP shown, both the heating medium flowing out of the evaporator 14 and the heating medium flowing out of the condenser 12 flow through the first switching valve 31 .

[0026] The heating medium circuit 20 preferably includes a condenser bypass path 12A for bypassing the heating medium from the condenser 12 , and a condenser flow rate regulating valve 12V. The condenser flow rate regulating valve 12V adjusts the flow rate ratio of the heating medium between the condenser 12 and the condenser bypass path 12A based on the flow rate command SH issued from the high-pressure side flow rate command source 12C.

[0027] exist Figure 1 In the example shown, the flow rate is adjusted by the condenser flow rate regulating valve 12V so that the entire amount of the heating medium flowing from the first switching valve 31 toward the condenser 12 flows into the condenser 12 instead of into the condenser bypass path 12A.

[0028] Furthermore, the heating medium circuit 20 preferably includes an evaporator bypass path 14A for bypassing the heating medium from the evaporator 14 and an evaporator flow rate regulating valve 14V configured to adjust the flow rate ratio of the heating medium between the evaporator 14 and the evaporator bypass path 14A. The evaporator flow rate regulating valve 14V adjusts the flow rate ratio of the heating medium between the evaporator 14 and the evaporator bypass path 14A based on the flow rate instruction SL issued from the low-pressure side flow rate instruction source 14C.

[0029] exist Figure 1 In the example shown, the evaporator flow rate regulating valve 14V regulates the flow rate so that the entire amount of the heating medium flowing from the first switching valve 31 toward the evaporator 14 flows into the evaporator 14 instead of into the evaporator bypass path 14A.

[0030] The condenser flow rate regulating valve 12V, which is a three-way valve in the present embodiment, can be replaced by two two-way valves capable of regulating the flow rate, or a single two-way valve capable of regulating the flow rate. For example, one two-way valve can be arranged on the condenser bypass path 12A, and the other two-way valve can be arranged on the piping between the condenser flow rate regulating valve 12V and the condenser 12. Alternatively, a single two-way valve can be arranged on one side of the condenser bypass path 12A and the piping. The evaporator flow rate regulating valve 14V can also be replaced with two two-way valves capable of regulating the flow rate, or a single two-way valve capable of regulating the flow rate, similarly to the above.

[0031] The first pump 21 and the second pump 22 are both electric pumps driven by a motor (not shown). The first pump 21 pumps the heating medium flowing out of the evaporator 14 and discharges it to pressurize the heating medium. The second pump 22 pumps the heating medium flowing out of the condenser 12 and discharges it to pressurize the heating medium.

[0032] As the pumps 21 and 22 , a well-known centrifugal pump or a positive displacement pump can be appropriately adopted.

[0033] The positions of the first pump 21 and the second pump 22 are not limited to the illustrated examples, and may be appropriately determined within a range where the heating medium can be pressure-fed by at least one of the first pump 21 and the second pump 22 in consideration of the heating medium path in each operation mode.

[0034] The outdoor heat exchanger 23 exchanges heat between the outside air outside the machine room 8 and the heat medium. The outdoor heat exchanger 23 is equivalent to a radiator arranged near the air inlet of the vehicle, for example. The outside air supplied to the outdoor heat exchanger 23 by the running of the vehicle and the operation of the outdoor blower 23A dissipates or absorbs heat based on the temperature difference between the outside air and the heat medium.

[0035] The outdoor heat exchanger bypass path 24 allows the heating medium to bypass the outdoor heat exchanger 23 .

[0036] The indoor heat exchanger 25 exchanges heat between the air sent by the indoor blower 25A and the heat medium, thereby providing conditioned air to the machine room 8. The indoor blower 25A is driven by a motor to blow the air in the machine room 8 (inside air) or outside air, or a mixed gas of the inside air and outside air toward the indoor heat exchanger 25. The indoor blower 25A is preferably configured to be variable in speed. The HVAC (Heating, Ventilation, and Air Conditioning) unit U includes an indoor heat exchanger 25, an indoor blower 25A, and a duct (not shown) through which the air sent by the indoor blower 25A flows.

[0037] By switching the flow of the heating medium by at least one of the first to third switching valves 31, 32, and 33, the heating medium circuit 20 is configured to be able to set the low-pressure side circuit C1 and the high-pressure side circuit C2 in parallel ( Figure 1 ), and is configured to be able to set a series circuit CC ( Figure 2 ).

[0038] The high-pressure circuit C2 of the heat medium flowing out of the condenser 12 and returning to the condenser 12 is separated from the low-pressure circuit C1 flowing out of the evaporator 14 and returning to the evaporator 14. Hereinafter, the low-pressure circuit C1 and the high-pressure circuit C2 may be referred to as parallel circuits C1 and C2. The heating medium of the high-pressure side circuit C2 including the condenser 12 and the heating medium of the low-pressure side circuit C1 including the evaporator 14 are not mixed with each other.

[0039] In the parallel circuit C1, C2 Figure 1 In the figure, the flow of the relatively low temperature heat medium (low temperature heat medium) circulating in the low pressure side circuit C1 is indicated by a solid line, and the flow of the relatively high temperature heat medium (high temperature heat medium) circulating in the high pressure side circuit C2 is indicated by a single dotted line. The path where neither the low temperature heat medium nor the high temperature heat medium is pressure-fed is indicated by a dotted line.

[0040] On the other hand, the series circuit CC is equivalent to a continuous circuit including the evaporator 14 and the condenser 12 arranged in series. When setting the series circuit CC, for example, Figure 2 As shown, the heat transfer medium flowing out of the condenser 12 flows into the evaporator 14 and then flows into the condenser 12 . In the series circuit CC Figure 2 In the figure, the flow of a relatively low temperature heat carrier is represented by a solid line, and the flow of a relatively high temperature heat carrier is represented by a dashed line. Figure 2 Unlike the case where parallel circuits C1 and C2 are provided, the flow of the heat medium from the evaporator 14 to the condenser 12 is indicated by a solid line, and the flow of the heat medium from the condenser 12 to the evaporator 14 is indicated by a dashed line. This means that if the heat medium flows into the evaporator 14, the temperature of the heat medium decreases due to heat dissipation to the refrigerant, and if the heat medium flows into the condenser 12, the temperature of the heat medium increases due to heat absorption from the refrigerant.

[0041] When the series circuit CC is set, the heat medium circulates in the condenser 12 and the evaporator 14 while repeating the temperature rise of the condenser 12 and the temperature drop of the evaporator 14. At this time, a continuous loop is formed in the heat medium circuit 20, so the heat medium can be pumped by only at least one of the first pump 21 and the second pump 22. However, even in the operation mode using the series circuit CC, by operating the two pumps 21 and 22 , a sufficient circulation flow rate of the heating medium in the heating medium circuit 20 can be obtained.

[0042] The first to third switching valves 31 to 33 are all electric valves that can be opened and closed based on a command from the control device 5 , and are configured to be able to switch the flow path of the heating medium according to each operation mode. In order to set a path required for realizing a desired operation mode in the heating medium circuit 20 , the first to third switching valves 31 to 33 can be replaced with electric valves having an appropriate structure and an appropriate number.

[0043] 〔Control device structure〕 like Figure 3 As shown in (a), the control device 5 corresponds to a computer including a memory 501, a calculation unit 502, a storage unit 503, and an input / output unit 504. The "computer" also includes a programmable logic controller (PLC: programmable logic controller).

[0044] like Figure 3 As shown in (b), the control device 5, in addition to the above-mentioned high-pressure side flow command source 12C and low-pressure side flow command source 14C, can also include: a temperature control unit 51, which cools or heats the temperature control object by driving control of the compressor 11, etc.; a low-pressure control unit 52, which controls the low pressure pL of the refrigerant circuit 10; a high-pressure control unit 53, which controls the high pressure pH of the refrigerant circuit 10; and a low-pressure / high-pressure control unit 54, which controls the low pressure pL and the high pressure pH. The high-pressure flow rate instruction source 12C, the low-pressure flow rate instruction source 14C, the temperature control unit 51, the low-pressure control unit 52, the high-pressure control unit 53, and the low-pressure / high-pressure control unit 54 may all be computer program modules read and executed from the storage unit 503. In the heater mode HT, the low-pressure pL is controlled, in particular, by the low-pressure control unit 52 or the low-pressure / high-pressure control unit 54, thereby ensuring the heating capacity.

[0045] In each operation mode, the temperature control unit 51 controls the driving of the compressor 11 and can increase or decrease the cooling capacity or the heating capacity by increasing or decreasing the circulation flow rate of the refrigerant. The temperature control unit 51 detects physical quantities related to the room temperature, such as the external air temperature, the blown temperature of the air-conditioned air, or the temperature of the heating medium or the temperature of the refrigerant, through sensors 61, 62, etc., and performs feedback control such as controlling the rotation speed of the compressor 11 to eliminate the deviation between the detected value and the target value, thereby adjusting the room temperature to the target temperature.

[0046] The operation amount by the feedback control of the temperature control unit 51 may be one or more of the rotation speed of the compressor 11 , the rotation speed of the indoor fan 25A, and the rotation speed of the pumps 21 , 22 . The rotation speeds of the compressor 11, the indoor fan 25A, and the pumps 21 and 22 can be controlled by increasing or decreasing the frequency or the duty ratio of the drive current applied to the motor through the drive circuit unit, for example.

[0047] In the heater mode HT, the low pressure control unit 52 controls the low pressure pL to be greater than or equal to 0.2 MPa and less than or equal to 1.2 MPa by adjusting the flow rate of the heating medium flowing through the evaporator 14 . The high-pressure control unit 53 preferably controls the high-pressure pH to 2.8 MPa or less by adjusting the flow rate of the heating medium flowing through the condenser 12 at least in the heater mode HT.

[0048] [Explanation of operation mode] First of all, Figure 1 The heat pump mode HP shown will be briefly described. Heat pump mode HP( Figure 1 ): The heat pump mode HP corresponds to a mode for heating the interior of the machine room 8 , and heat is extracted from the outside air as a heat source to a high-temperature heating medium having a higher temperature than the outside air and transmitted to the machine room 8 , thereby heating the interior of the machine room 8 .

[0049] In the heat pump mode HP, the temperature control system 1 operates using the parallel circuits C1 and C2. The low-temperature heat medium flowing out of the evaporator 14 flows into the outdoor heat exchanger 23 through the second switching valve 32 as shown by the solid arrow. The heat medium that absorbs heat from the outside air returns to the evaporator 14 through the first switching valve 31 and the evaporator flow control valve 14V. The refrigerant evaporates by absorbing heat from the heating medium flowing into the evaporator 14, and is sucked into the compressor 11. The refrigerant discharged from the compressor 11 condenses in the condenser 12 by dissipating heat to the heating medium, thereby raising the temperature of the heating medium.

[0050] As indicated by the dashed arrow, the high-temperature heating medium flowing out of the condenser 12 flows into the indoor heat exchanger 25 via the third switching valve 33. The heating medium heated in the machine room 8 returns to the condenser 12 via the first switching valve 31 and the condenser flow control valve 12V.

[0051] The heat pump mode HP utilizes the outside air as a part of the heat source, thereby ensuring the heating capacity while suppressing the increase in the power of the compressor 11, the pumps 21, 22, and the like.

[0052] Heater mode HT( Figure 2 ): Next, refer to Figure 2 , the operation mode using the series circuit CC, namely the heater mode HT, is described. When the outside air temperature is significantly lower than 0°C, for example, when the outside air temperature drops below -20°C, the amount of heat that can be absorbed from the outside air to the heat medium by the above-mentioned heat pump mode HP is reduced, and the density of the refrigerant sucked into the compressor 11 is reduced, and the power of the compressor 11 becomes smaller. Even in this case, the heater mode HT can be used to heat the temperature control object by using the compressor 11 as a heat source.

[0053] In the heater mode HT, heat corresponding to the supplied power is supplied to the temperature-controlled object, for example, similarly to a resistance heating electric heater. Therefore, although it is called a "heater" mode, the name of the heater mode HT is not necessarily limited to this. In addition, since the startup heater mode HT0 described later is a mode presupposing a transition to the heater mode HT, the same name as the heater mode HT is used, but the name of the startup heater mode HT0 is not necessarily limited to this.

[0054] The flow of the heating medium in the heater mode HT is described. In order to prevent the heat transfer of the heating medium to the outside air, the heating medium is detoured from the outdoor heat exchanger 23 through the outdoor heat exchanger bypass path 24. At this time, the operation of the outdoor blower 23A may also be stopped. In addition, at least one of the pumps 21 and 22 is operated at an appropriate rotation speed.

[0055] The heat medium that absorbs heat from the refrigerant in the condenser 12 flows into the indoor heat exchanger 25 via the third switching valve 33 to provide heating in the machine room 8. Then, the heat medium that flows out of the indoor heat exchanger 25 flows into at least the evaporator 14 and the evaporator 14 in the evaporator bypass path 14A via the first switching valve 31 and the evaporator flow regulating valve 14V to dissipate heat to the refrigerant. The heat carrier flowing out of the evaporator 14 flows into the outdoor heat exchanger bypass path 24 from the second switching valve 32, and after merging with the flow from the first switching valve 31 toward the condenser 12 between the first switching valve 31 and the condenser flow regulating valve 12V, flows into at least the condenser 12 and the condenser 12 in the condenser bypass path 12A, thereby absorbing heat from the refrigerant.

[0056] In the heater mode HT, the heat medium flows in the outdoor heat exchanger bypass path 24 to avoid heat dissipation to the outside air, while receiving heat generated by the power of the compressor 11 from the refrigerant and transferring it to the temperature control object. According to the heater mode HT, the system operates without heat input and output with the outside air, so that the heating in the machine room 8 can continue regardless of the outside air temperature.

[0057] Figure 4Refrigeration cycle Y1 (dashed line) in heat pump mode HP and refrigeration cycle Y2 (solid line) in heater mode HT are shown in FIG. Refrigeration cycles Y1 and Y2 are both based on the condition that the outside air temperature is -20°C. In the heat pump mode HP, the refrigerant needs to absorb heat from the heating medium that flows into the evaporator 14 by exchanging heat with the outside air at -20°C, so the low pressure pL decreases. On the other hand, in the heater mode HT, the heat medium passing through the condenser 12 and the indoor heat exchanger 25 dissipates heat to the refrigerant through the evaporator 14, so that Figure 4 As shown, the low pressure pL increases compared to the heat pump mode HP. The density of the refrigerant sucked into the compressor 11 (hereinafter, compressor suction density ρ) increases accordingly, so that the power of the compressor 11 increases and the circulation flow rate of the refrigerant increases. As a result of the low pressure increase, the volumetric efficiency of the heater mode HT is about three times greater than that of the heat pump mode HP. The volumetric efficiency is equivalent to the product of the enthalpy difference Δh and the compressor suction density ρ.

[0058] [Low pressure-compressor dynamic characteristics in heater mode] Figure 5 The figure shows the relationship between the low pressure pL (horizontal axis) and the power of the compressor 11 (vertical axis) in the heater mode HT. This is a result calculated under the condition that the high pressure pH is constant and the speed of the compressor 11 is also constant. The solid line shows the case of R1234yf, and the single-point dash line shows the case of propane (R290). For any refrigerant, the low pressure-compressor power characteristic LPP presents a peak-shaped curve, with the peak value at about 1 MPa. The following applies to both refrigerants unless otherwise specified.

[0059] Figure 5 The value range of the low pressure pL shown is 0.1 MPa or more and 2.1 MPa or less. The low pressure pL starts from 0.1 MPa, rises to a peak value while the increase rate gradually decreases, and when it exceeds the peak value and turns to decrease, it decreases while the decrease rate gradually increases.

[0060] As the low pressure pL increases from 0.1 MPa to 1 MPa, the power of the compressor 11 increases, and therefore the heating capacity based on heat corresponding to the power of the compressor 11 also increases. However, if the low pressure pL exceeds the peak value and becomes too high, sufficient heating capacity cannot be obtained for the low outside air temperature due to the reduction in power. Since the low pressure pL gradually decreases from the peak value, even if it exceeds the peak value, the heating capacity up to 1.2 MPa with a change rate of less than 10 kW / MPa can be allowed.

[0061] This low pressure compressor dynamic characteristic LPP is consistent with the refrigeration cycle Y2 ( Figure 4) corresponds. If the low pressure pL rises, the power of the compressor 11 increases as the compressor suction density ρ increases, while the pressure difference Δp between the high pressure pH and the low pressure pL decreases. Therefore, as the enthalpy difference Δh( Figure 4 ) decreases, the power of the compressor 11 decreases. That is, during the period when the low pressure pL rises to 1 MPa, the increase in power caused by the increase in the compressor suction density ρ is greater than the decrease in power caused by the decrease in the enthalpy difference Δh.

[0062] From the viewpoint of sufficiently ensuring the enthalpy difference Δh, the low pressure pL is preferably set within a range not exceeding a median value (0.7 MPa) between 0.2 MPa and 1.2 MPa. This range may be, for example, 0.3 MPa to 0.6 MPa. On the other hand, from the viewpoint of ensuring sufficient compressor suction density ρ, the low pressure pL is preferably set to a range greater than the median value (0.7 MPa) between 0.2 MPa and 1.2 MPa. This range may be, for example, 0.8 MPa to 1.1 MPa.

[0063] According to the low pressure-compressor dynamic characteristic LPP, even if the low pressure pL rises in the heater mode HT, if the low pressure pL is too low or too high, the heating capacity will not increase, so the effect of increasing the heating capacity cannot necessarily be obtained. Therefore, in order to ensure sufficient heating capacity at low outside air temperature, the low pressure control unit 52 maintains the low pressure pL at 0.2 MPa or more and 1.2 MPa or less in the heater mode HT. This control of the low pressure pL is based on the fact that, unlike the heat pump mode HP, the heater mode HT does not absorb heat from the outside air to the heating medium, and therefore the low pressure pL can be freely increased to a pressure corresponding to saturated steam or higher.

[0064] exist Figure 5 In the figure, p1 is equivalent to 0.2MPa and p2 is equivalent to 1.2MPa. Here, for R1234yf, if the maximum value of the compressor power is assumed to be 100%, the compressor power F1 corresponding to p1 is equivalent to about 40%, and the compressor power F2 corresponding to p2 is equivalent to about 98%. Similarly, for propane, if the maximum value of the compressor power is assumed to be 100%, the compressor power f1 corresponding to p1 is equivalent to about 41%, and the compressor power f2 corresponding to p2 is equivalent to about 98%. The difference between F2 and f2 is greater than the difference between F1 and f1.

[0065] Regarding other refrigerants, similar to R1234yf and propane, when the peak value of the low pressure pL is about 1 MPa, the compressor power corresponding to p1 is 35% to 45%, and the compressor power corresponding to p2 is 95% to 100%, the low pressure pL can be maintained in the range of above 0.2 MPa and below 1.2 MPa, and sufficient heating capacity can be obtained relative to the low outside air temperature.

[0066] [High-pressure-compressor dynamic characteristics in heater mode] The relationship between the high-pressure pH and the compressor power in the heater mode HT is omitted. As the high-pressure pH increases, the compressor power gradually increases, so the higher the high-pressure pH, the higher the heating capacity. From the viewpoint of increasing the pressure difference Δp to fully ensure the heating capacity, it is preferred to set the high-pressure pH as high as possible within the range of ensuring the pressure resistance of the equipment such as the housing of the compressor 11. Therefore, the high-pressure control unit 53 preferably limits the high-pressure pH to, for example, more than twice the low pressure pL and less than 2.8 MPa at least in the heater mode HT.

[0067] [Refrigerant pressure control in heater mode] In the heater mode HT, the low pressure pL is controlled to the above-mentioned value, so the evaporator bypass path 14A and the evaporator flow rate regulating valve 14V can be used. If the flow rate ratio of the heating medium flowing into the evaporator 14 and the heating medium flowing into the evaporator bypass path 14A is changed, the flow rate of the heating medium circulating in the path of the evaporator 14 including the heating medium circuit 20 changes. As a result, the heat dissipation from the heating medium to the refrigerant in the evaporator 14 changes, and the low pressure pL changes.

[0068] The low-pressure control unit 52 of the present embodiment can detect the low pressure pL detected by the low-pressure pressure sensor 63 while generating a low-pressure side flow instruction SL from the low-pressure side flow instruction source 14C to the evaporator flow regulating valve 14V, thereby giving feedback control of the flow ratio as the operating quantity to the evaporator 14 and the evaporator bypass path 14A, so as to eliminate the deviation between the detected value and the target pressure.

[0069] Furthermore, in order to control the high-pressure pH to the above-mentioned value in the heater mode HT, the condenser bypass path 12A and the condenser flow rate regulating valve 12V can be used. If the flow rate ratio of the heating medium flowing into the condenser 12 and the heating medium flowing into the condenser bypass path 12A is changed, the flow rate of the heating medium circulating in the path of the condenser 12 including the heating medium circuit 20 changes. Accordingly, the amount of heat absorbed from the refrigerant to the heating medium in the condenser 12 changes, and the high-pressure pH changes.

[0070] The high-pressure control unit 53 of the present embodiment can detect the high-pressure pH detected by the high-pressure pressure sensor 64 while generating a high-pressure side flow instruction SH from the high-pressure side flow instruction source 12C to the condenser flow regulating valve 12V, thereby giving feedback control of the flow ratio as the operating quantity to the condenser 12 and the condenser bypass path 12A, so as to eliminate the deviation between the detected value and the target pressure.

[0071] [Main effects based on this embodiment]

[0072] Based on the low-pressure-compressor dynamic characteristic LPP under the heater mode HT, the low pressure pL is controlled to be above 0.2 MPa and below 1.2 MPa. Thus, even when the outside air temperature is significantly lower than 0°C, the heating capacity can be ensured by the heater mode HT, so that the temperature in the machine room 8 can reach the target temperature in advance.

[0073] Furthermore, in the heater mode HT using the series circuit CC, since the condenser 12 and the evaporator 14 are connected in series, the temperature of the heating medium flowing out of the condenser 12 can be increased more quickly than when the heating medium flows in parallel into the condenser 12 and the evaporator 14. Furthermore, since the amount of heating medium circulating in the indoor heat exchanger 25 is large, the amount of heat exchange between the heating medium and the air becomes large.

[0074] The evaporator bypass path 14A, evaporator flow control valve 14V, and low-pressure flow command source 14C capable of controlling low pressure pL are provided, and the condenser bypass path 12A, condenser flow control valve 12V, and high-pressure flow command source 12C capable of controlling high pressure pH are provided, thereby being able to adjust low pressure pL and high pressure pH respectively in heater mode HT. Appropriate values ​​can be given to low pressure pL and high pressure pH respectively to achieve desired heating capacity. At this time, the expansion valve 13 may be controlled so that the degree of subcooling of the refrigerant at the outlet of the condenser 12 becomes a constant value.

[0075] [First Modification] The control of the low pressure pL and the high pressure pH in the heater mode HT can also be performed by controlling the rotation speed N of the compressor 11 . In this case, the compressor 11 is configured such that the rotation speed N of the compressor mechanism can be varied by a drive circuit portion (not shown) that applies a drive current to the motor.

[0076] When the rotation speed N of the compressor 11 increases, the refrigerant flow rates of the evaporator 14 and the condenser 12 increase respectively, the heat dissipation from the heating medium to the refrigerant in the evaporator 14 and the heat absorption from the refrigerant to the heating medium in the condenser 12 increase, and thus the low pressure pL and the high pressure pH rise. On the other hand, if the rotation speed N of the compressor 11 decreases, the refrigerant flow rates of the evaporator 14 and the condenser 12 are reduced, respectively, the heat dissipation from the heat medium to the refrigerant in the evaporator 14 and the heat absorption from the refrigerant to the heat medium in the condenser 12 are reduced, and thus the low pressure pL and the high pressure pH decrease.

[0077] The low pressure / high pressure control unit 54 can, for example, detect the low pressure pL detected by the low pressure sensor 63 while performing feedback control of giving the number of revolutions N (control command) as an operation amount to the drive circuit unit of the compressor 11 through the control device 5, so as to eliminate the deviation between the detected value and the target pressure. At this time, the low pressure / high pressure control unit 54 limits the high pressure pH to an upper limit of 2.8 MPa or less.

[0078] [Second Modification] The control of the low pressure pL and the high pressure pH in the heater mode HT can also be performed by controlling the rotation speed n of the pumps 21 and 22 . In this case, it is preferable that at least one of the pumps 21 and 22 is configured so that the rotation speed n of the mechanism for pressurizing the heating medium can be variably controlled by a drive circuit portion (not shown) for applying a drive current to the motor.

[0079] The pumps 21 and 22 operate at a predetermined efficiency η. In simple terms, the product of the axial force P output from the motor to the pumps 21 and 22 and (1-efficiency η), i.e., most of the loss, is transferred to the heat medium as heat energy. If the rotation speed n of the pumps 21 and 22 increases, the discharge flow rate of the heat medium based on the pumps 21 and 22 increases, and the amount of heat transferred from the pumps 21 and 22 to the heat medium increases. As a result, the amount of heat dissipated from the heat medium in the evaporator 14 to the refrigerant increases, and the low pressure pL rises. Furthermore, due to the increase in the discharge flow rate of the heating medium by the pumps 21 and 22, the amount of heat absorbed from the refrigerant to the heating medium in the condenser 12 increases.

[0080] On the other hand, when the rotation speed n of the pumps 21 and 22 decreases, the discharge flow rate of the heating medium by the pumps 21 and 22 decreases, and the amount of heat transferred from the pumps 21 and 22 to the heating medium decreases. Then, the amount of heat dissipated from the heating medium to the refrigerant in the evaporator 14 and the amount of heat absorbed from the refrigerant to the heating medium in the condenser 12 decrease, so that the low pressure pL and the high pressure pH decrease.

[0081] The low pressure / high pressure control unit 54 can, for example, detect the low pressure pL detected by the low pressure pressure sensor 63 while performing feedback control by giving the number of revolutions n (control command) as an operation amount to the drive circuit unit of the pumps 21 and 22 through the control device 5, so as to eliminate the deviation between the detected value and the target pressure. At this time, the low pressure / high pressure control unit 54 limits the high pressure pH to an upper limit of 2.8 MPa or less.

[0082] When the discharge flow rate of the heating medium by the pumps 21 and 22 is variably configured by adjusting the opening degree of the discharge ports of the pumps 21 and 22 or the like, the discharge flow rate can be feedback-controlled as the operation amount instead of the rotation speed n.

[0083] [Third Modification] In the heater mode HT, the low pressure pL and the high pressure pH can be controlled separately according to the air-conditioning load as the heat load. Here, the "air conditioning load" as a cooling load or a heating load is defined by the following formula (1). The air temperature in the formula is strictly speaking the air enthalpy. The air volume in the formula is strictly speaking the mass flow rate. Air conditioning load L = air volume Q × (target outlet air temperature TT - intake air temperature TI) (1) The heating load increases as the outside air temperature decreases.

[0084] The air volume Q is the volume flow rate of air sent to the indoor heat exchanger 25 by the indoor blower 25A and the running of the vehicle. The air volume Q can be obtained based on the setting level of the occupant or the setting level of the temperature control system 1, and the blowing mode (Face / Foot / Defogger, etc.). The target outlet air temperature TT is a target temperature of the air blown from the HVAC unit U into the machine room 8, and is set according to the target temperature of the air in the machine room 8. The target outlet air temperature TT is detected by the temperature sensor 62. The intake air temperature TI refers to the temperature of the air introduced into the indoor heat exchanger 25 by the indoor blower 25A and the running of the vehicle. When an internal air circulation is provided, the intake air temperature TI corresponds to the room temperature in the machine room 8 detected by a room temperature sensor (not shown), and when an external air introduction is provided, it corresponds to the external air temperature detected by the external air temperature sensor 61. When the outside air temperature is significantly lower than 0° C., the difference ΔT between TT and TI is large, so the heating load is high.

[0085] In the heater mode HT, the control device 5 performs the following control, for example: the lower the air-conditioning load L calculated by the formula (1), the lower the low pressure pL is through the evaporator flow regulating valve 14V; the higher the air-conditioning load L is, the higher the low pressure pL is through the evaporator flow regulating valve 14V. Furthermore, when the air-conditioning load L is low, the high-pressure pH is lowered by reducing the target degree of subcooling at the condenser outlet of the expansion valve 13 .

[0086] Regarding the control of the high-pressure pH in the heater mode HT, the control device 5 performs the following control, for example: the lower the air-conditioning load L calculated by the formula (1), the lower the high-pressure pH is through the condenser flow regulating valve 12V; the higher the air-conditioning load L, the higher the high-pressure pH is through the condenser flow regulating valve 12V.

[0087] Here, since the low pressure pL and the high pressure pH are controlled according to the air conditioning load L, the rotation speed N of the compressor 11 or the rotation speed n of the pumps 21 and 22 can be increased or decreased instead of changing the flow ratio using the evaporator flow control valve 14V and the condenser flow control valve 12V.

[0088] According to the third modification, it is possible to operate in the power saving mode while ensuring sufficient heating capacity for the air-conditioning load L and suppressing power. Even when the air conditioning load L is low, the rotation speed N of the compressor 11 cannot be reduced below the rotation speed required to return the lubricating oil to the compressor 11. Therefore, it is effective to reduce the low pressure pL in order to make the air conditioning load L correspond to the heating capacity.

[0089] [Fourth Modification] The temperature control unit 51 sometimes increases or decreases the rotation speed N of the compressor 11 according to the air conditioning load L. In this case, by applying a threshold value to the rotation speed N of the compressor 11 instead of the air conditioning load L, the low pressure pL and the high pressure pH can be controlled separately as described above. For example, when the rotation speed N of the compressor 11 is less than a predetermined first threshold value, the flow rate of the heat medium flowing into the evaporator 14 is reduced by the evaporator flow regulating valve 14V, similarly to the feedback control described in the above embodiment, so that the low pressure pL of the refrigerant circuit 10 is reduced. When the rotation speed N is greater than a second threshold value greater than the first threshold value, the flow rate of the heat medium flowing into the evaporator 14 is increased by the evaporator flow regulating valve 14V, thereby raising the low pressure pL of the refrigerant circuit 10, similarly to the feedback control described in the above embodiment.

[0090] In order to control the low pressure pL and the high pressure pH according to the rotation speed N, the rotation speed n of the pumps 21 and 22 may be increased or decreased instead of changing the flow rate ratio using the evaporator flow control valve 14V and the condenser flow control valve 12V.

[0091] According to the fourth modification, it is also possible to operate in the power saving mode while suppressing power while ensuring sufficient heating capacity for the air-conditioning load L.

[0092] [Fifth Modification] The temperature control system 1 of the above embodiment may also include Figure 6 The heater mode HT0 at start-up is shown. The heater mode HT0 at start-up uses a series circuit CC. In the startup heater mode HT0, the heating medium absorbs heat from the outside air through the outdoor heat exchanger 23. Therefore, the heating medium is made to flow into the outdoor heat exchanger 23. Furthermore, in order to give priority to the heating of the refrigerant over the heating in the machine room 8, the heating medium is made to bypass the condenser bypass path 12A instead of flowing into the condenser 12, thereby preventing the refrigerant from radiating heat to the heating medium. Then, in the evaporator 14, the heat is radiated from the heating medium to the refrigerant. Furthermore, in order to suppress heat exchange between the air and the heating medium in the indoor heat exchanger 25, it is preferable to stop the operation of the indoor air-sending fan 25A.

[0093] The heat exchange between the heating medium and the refrigerant and the heat exchange between the heating medium and the air are suppressed from the outlet of the outdoor heat exchanger 23 through the condenser bypass path 12A and the indoor heat exchanger 25 to the inlet of the evaporator 14. The heating medium, which absorbs heat from the outside air, passes through the condenser bypass path 12A and the indoor heat exchanger 25, and transfers the heat to the evaporator 14 where the refrigerant flows.

[0094] During the period when the vehicle is stopped in a state where the outside air temperature is very low and below freezing, the temperatures of the heating medium and the refrigerant drop to the same level as the outside air temperature. Therefore, the start-up of the compressor 11 begins by starting the temperature control system 1. Immediately after the refrigeration cycle starts, the low pressure of the refrigerant circuit 10 drops due to the refrigerant cooling the heating medium, and the evaporation temperature of the refrigerant is lower than the outside air temperature. However, according to the heater mode HT0 at startup, the low pressure of the refrigerant circuit 10 gradually rises and the evaporation temperature also rises by continuously transferring the heat absorbed from the outside air to the heating medium to the refrigerant. Then, the low pressure of the refrigerant circuit 10 rises to the specified value, and the refrigerant circuit 10 operates stably, thereby being able to heat the temperature control object by extracting heat from the power of the compressor 11 to the heating medium, and thus it is possible to transfer to the heater mode HT.

[0095] If the temperature of the heating medium exceeds the outside air temperature, the heat absorption from the outside air becomes insufficient, so the control device 5 can make the temperature control system 1 shift to the heater mode HT when the heating medium approaches the outside air temperature. For example, the temperature of the heating medium can be shifted to the heater mode HT when the temperature of the heating medium exceeds the threshold value T of a predetermined temperature difference α relative to the outside air temperature (e.g., -20°C).3 When it is turned on, it can be transferred to heater mode HT.

[0096] In addition to the above, the structures listed in the above embodiments may be selected or replaced, or may be appropriately changed to other structures. The various control methods for low pressure pL disclosed above can be combined as appropriate. Similarly, the various control methods for high pressure pH disclosed above can also be combined as appropriate.

[0097] It is sufficient that the temperature control system 1 has at least the heater mode HT. The temperature control system 1 may include other temperature control devices such as a battery device in addition to or in place of the indoor heat exchanger 25 as a temperature control device. In this case, the heating medium circuit 20 includes a path for cooling or heating other temperature control devices with the heating medium.

[0098] [Note] Through the above disclosure, the structure described below will be understood. [1] A temperature control system for a vehicle, comprising: The refrigerant circuit 10 includes a compressor 11, a high-pressure side heat exchanger 12, a pressure reducing unit 13, and a low-pressure side heat exchanger 14, and is configured so that the refrigerant can circulate according to a refrigeration cycle; and The heating medium circuit (20) is configured to circulate a heating medium for exchanging heat with the refrigerant; and The control device 5 is configured to control the pressure of the refrigerant in the refrigerant circuit 10. The heat carrier circuit 20 comprises: The high-pressure side heat exchanger 12 enables the refrigerant to exchange heat with the heat carrier; The low-pressure side heat exchanger 14 enables the refrigerant to exchange heat with the heat carrier; Pumps 21 and 22 are configured to pressurize the heat medium; The outdoor heat exchanger 23 allows the external air to exchange heat with the heat carrier; The temperature control device 25 is equivalent to the temperature control object heated or cooled by the heat carrier, or is used to heat or cool the temperature control object; and The outdoor heat exchanger bypass path 24 allows the heat medium to bypass the outdoor heat exchanger 23. The control device 5 is configured as follows: In the compressor heat source mode HT, in which the heat carrier flowing out of the high-pressure side heat exchanger 12 flows into the low-pressure side heat exchanger 14 via the temperature control device 25 and then flows into the high-pressure side heat exchanger 12 through the outdoor heat exchanger bypass path 24, the low pressure pL of the refrigerant circuit 10 is controlled to be above 0.2 MPa and below 1.2 MPa by adjusting the flow rate of the heat carrier flowing in the low-pressure side heat exchanger 14.

[0099] [2] A vehicle temperature control system according to item [1], wherein: The refrigerant corresponds to R1234yf or propane.

[0100] [3] A vehicle temperature control system according to [1] or [2], wherein: The heat carrier circuit 20 comprises: A low-pressure side bypass path 14A allows the heat medium to bypass the low-pressure side heat exchanger 14; and The low-pressure flow rate regulating valve 14V is configured to be able to adjust the flow rate ratio of the heating medium between the low-pressure heat exchanger 14 and the low-pressure bypass path 14A. The control device 5 is configured to control the low pressure pL by adjusting the flow rate ratio based on a control command for the low-pressure side flow rate regulating valve 14V in the compressor heat source mode HT.

[0101] [4] A vehicle temperature control system according to any one of [1] to [3], wherein: The compressor 11 is configured to variably control the rotation speed of the mechanism for compressing the refrigerant. The control device 5 is configured to control at least the low pressure pL of the low pressure pL and the high pressure pH of the refrigerant circuit 10 by controlling the rotation speed based on a control instruction for the compressor 11 and adjusting the flow rate of the refrigerant in the compressor heat source mode HT.

[0102] [5] A vehicle temperature control system according to any one of [1] to [4], wherein: The pumps 21 and 22 are configured to variably control the rotation speed of the mechanism for pressurizing the heat medium or the discharge flow rate of the heat medium discharged from the pumps 21 and 22. The control device 5 is configured to control at least the low pressure pL of the low pressure pL and the high pressure pH of the refrigerant circuit 10 by controlling the rotation speed or the discharge flow rate based on a control command to the pumps 21 and 22 in the compressor heat source mode HT.

[0103] [6] A vehicle temperature control system according to any one of [1] to [5], wherein: The control device 5 is configured as follows: In the compressor heat source mode HT, at least the low pressure pL of the low pressure pL and the high pressure pH of the refrigerant circuit 10 is controlled according to the heat load or the rotation speed of the compressor 11 .

[0104] [7] A vehicle temperature control system according to any one of [1] to [6], wherein: The heat carrier circuit 20 comprises: A high-pressure side bypass path 12A allows the heat medium to bypass the high-pressure side heat exchanger 12; and The high-pressure side flow rate regulating valve 12V is configured to be able to adjust the flow rate ratio of the heating medium between the high-pressure side heat exchanger 12 and the high-pressure side bypass path 12A. The control device 5 is configured to control the high-pressure pH of the refrigerant circuit 10 by adjusting the flow rate ratio based on a control command for the high-pressure side flow rate regulating valve 12V in the compressor heat source mode HT.

[0105] [8] A vehicle temperature control method, which is a temperature control method using a vehicle temperature control system, wherein: The temperature control system has: The refrigerant circuit 10 includes a compressor 11, a high-pressure side heat exchanger 12, a pressure reducing unit 13, and a low-pressure side heat exchanger 14, and is configured so that the refrigerant can circulate according to a refrigeration cycle; and The heating medium circuit (20) is configured to circulate a heating medium for exchanging heat with the refrigerant. The heat carrier circuit 20 comprises: The high-pressure side heat exchanger 12 enables the refrigerant to exchange heat with the heat carrier; The low-pressure side heat exchanger 14 enables the refrigerant to exchange heat with the heat carrier; Pumps 21 and 22 are configured to pressurize the heat medium; The outdoor heat exchanger 23 allows the external air to exchange heat with the heat carrier; The temperature control device 25 is equivalent to the temperature control object heated or cooled by the heat carrier, or is used to heat or cool the temperature control object; and The outdoor heat exchanger bypass path 24 allows the heat medium to bypass the outdoor heat exchanger 23. The temperature control method, In the compressor heat source mode HT, in which the heat carrier flowing out of the high-pressure side heat exchanger 12 flows into the low-pressure side heat exchanger 14 via the temperature control device 25 and then flows into the high-pressure side heat exchanger 12 through the outdoor heat exchanger bypass path 24, the low pressure of the refrigerant circuit 10 is controlled to be above 0.2 MPa and below 1.2 MPa by adjusting the flow rate of the heat carrier flowing in the low-pressure side heat exchanger 14. Explanation of symbols

[0106] 1- Temperature control system, 5- Control device, 8- Machine room, 10- Refrigerant circuit, 11- Compressor, 12- Condenser (High-pressure side heat exchanger), 12A- Condenser bypass path (High-pressure side bypass path), 12C- High-pressure side flow command source, 12V- Condenser flow control valve (High-pressure side flow control valve), 13- Expansion valve (Decompression section), 14- Evaporator (Low-pressure side heat exchanger), 14A- Evaporator bypass path (Low-pressure side bypass path), 14C- Low-pressure side flow command source, 14V- Evaporator flow control valve, 20- Heat medium circuit, 21- 1st pump, 22- 2nd pump, 23- Outdoor heat exchanger, 23A- Outdoor fan, 24- Outdoor heat exchanger bypass path, 25- Indoor heat exchanger (temperature control device), 25A- Indoor fan, 31- 1st switching valve, 3 2-the second switching valve, 33-the third switching valve, 51-temperature control unit, 52-low pressure control unit, 53-high pressure control unit, 54-low pressure / high pressure control unit, 61-external air temperature sensor, 62-temperature sensor, 63-low pressure pressure sensor, 64-high pressure pressure sensor, 501-memory, 502-calculation unit, 503-storage unit, 504-input and output unit, C1-low pressure side circuit, C2-high pressure side circuit, CC-series circuit, F1, F2-compressor power, f1, f2-compressor power, HP-heat pump mode, HT-heater mode, HT0-heater mode at startup, LPP-low pressure-compressor power characteristics, U-HVAC unit, Y1, Y2-refrigeration cycle, pH-high pressure, pL-low pressure, Δh-enthalpy difference, Δp-pressure difference.

Claims

1. A temperature control system for a vehicle, comprising: A refrigerant circuit includes a compressor, a high-pressure side heat exchanger, a pressure reducing unit, and a low-pressure side heat exchanger, and is configured so that the refrigerant can circulate according to a refrigeration cycle; A heat medium circuit configured to circulate a heat medium for exchanging heat with the refrigerant; and a control device configured to control the pressure of the refrigerant in the refrigerant circuit; The heat carrier circuit comprises: The high-pressure side heat exchanger enables the refrigerant to exchange heat with the heat carrier; The low-pressure side heat exchanger enables the refrigerant to exchange heat with the heat carrier; a pump configured to pressurize the heat carrier; An outdoor heat exchanger is used to exchange heat between the external air and the heat carrier; The temperature control device is equivalent to the temperature control object heated or cooled by the heat carrier, or is used to heat or cool the temperature control object; and The outdoor heat exchanger bypass path allows the heat medium to bypass the outdoor heat exchanger. The control device is configured as follows: In the compressor heat source mode, the heat carrier flowing out of the high-pressure side heat exchanger flows into the low-pressure side heat exchanger via the temperature control device and then flows into the high-pressure side heat exchanger through the outdoor heat exchanger bypass path, the low pressure of the refrigerant circuit is controlled to be above 0.2MPa and below 1.2MPa by adjusting the flow rate of the heat carrier flowing in the low-pressure side heat exchanger.

2. The vehicle temperature control system according to claim 1, wherein: The refrigerant corresponds to R1234yf or propane.

3. The vehicle temperature control system according to claim 1 or 2, wherein: The heat carrier circuit comprises: A low-pressure side bypass path allows the heat medium to bypass the low-pressure side heat exchanger; and The low-pressure side flow rate regulating valve is configured to be able to adjust a flow rate ratio of the heat medium between the low-pressure side heat exchanger and the low-pressure side bypass path. The control device is configured to control the low pressure by adjusting the flow rate ratio based on a control command to the low-pressure side flow rate regulating valve in the compressor heat source mode.

4. The vehicle temperature control system according to claim 1 or 2, wherein: The compression mechanism is a mechanism capable of variably controlling the rotation speed of the mechanism for compressing the refrigerant. The control device is configured as follows: In the compressor heat source mode, the rotation speed is controlled based on a control command to the compressor to adjust the flow rate of the refrigerant, thereby controlling at least the low pressure of the refrigerant circuit.

5. The vehicle temperature control system according to claim 1 or 2, wherein: The pump is configured to variably control the rotation speed of a mechanism for pressurizing the heat medium or the discharge flow rate of the heat medium discharged from the pump. The control device is configured as follows: In the compressor heat source mode, the rotation speed or the discharge flow rate is controlled based on a control command to the pump, thereby controlling at least the low pressure of the refrigerant circuit.

6. The vehicle temperature control system according to claim 1 or 2, wherein: The control device is configured as follows: In the compressor heat source mode, at least the low pressure of the refrigerant circuit is controlled according to a heat load or a rotation speed of the compressor.

7. The vehicle temperature control system according to claim 1 or 2, wherein: The heat carrier circuit comprises: A high-pressure side bypass path allows the heat medium to bypass the high-pressure side heat exchanger; and The high-pressure side flow rate regulating valve is configured to be able to adjust the flow rate ratio of the heat medium between the high-pressure side heat exchanger and the high-pressure side bypass path. The control device is configured as follows: In the compressor heat source mode, the high pressure of the refrigerant circuit is controlled by adjusting the flow ratio based on a control command for the high-pressure side flow rate regulating valve.

8. A vehicle temperature control method, which is a temperature control method using a vehicle temperature control system, wherein: The temperature control system has: A refrigerant circuit includes a compressor, a high-pressure side heat exchanger, a pressure reducing unit, and a low-pressure side heat exchanger, and is configured so that the refrigerant can circulate according to a refrigeration cycle; The heat medium circuit is configured to circulate a heat medium for exchanging heat with the refrigerant. The heat carrier circuit comprises: The high-pressure side heat exchanger enables the refrigerant to exchange heat with the heat carrier; The low-pressure side heat exchanger enables the refrigerant to exchange heat with the heat carrier; a pump configured to pressurize the heat carrier; An outdoor heat exchanger is used to exchange heat between the external air and the heat carrier; The temperature control device is equivalent to the temperature control object heated or cooled by the heat carrier, or is used to heat or cool the temperature control object; and The outdoor heat exchanger bypass path allows the heat medium to bypass the outdoor heat exchanger. The temperature control method, In the compressor heat source mode, in which the heat carrier flowing out of the high-pressure side heat exchanger flows into the low-pressure side heat exchanger via the temperature control device and then flows into the high-pressure side heat exchanger through the outdoor heat exchanger bypass path, the low pressure of the refrigerant circuit is controlled to be above 0.2MPa and below 1.2MPa by adjusting the flow rate of the heat carrier flowing in the low-pressure side heat exchanger.

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