Vehicular air-conditioner

Abstract

To provide a vehicular air-conditioner with a good quick warming performance.SOLUTION: A vehicular air-conditioner 1 is equipped with a refrigerant circuit 10 that includes a compressor 11, a heater core 12 configured to heat air to be supplied into a vehicle cabin, a decompression device 13, a low temperature side heat exchanger 14 in which a refrigerant exchanges heat, and a refrigerant channel 10x that is a low temperature side heat exchanger detouring the low temperature side heat exchanger 14. A control device 200, in a hot gas heating mode for flowing a part of a refrigerant passing through the compressor 11 to the heater core 12 and flowing the rest of the refrigerant to the bypass path, can perform control in which the refrigerant circulates in the compressor 11, the heater core 12, the decompression device 13, and the low temperature side heat exchanger bypass channel and detours the low temperature side heat exchanger 14.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an air conditioner for a vehicle. [Background technology]

[0002] Air conditioners using heat pumps are known as air conditioners for electric vehicles (EVs) that do not have a combustion heat source such as an engine, or for vehicles with a low amount of heat from a combustion heat source. However, air conditioners using heat pumps have difficulty absorbing heat from outside air when the outside temperature is extremely low, so the heating efficiency decreases. For this reason, for example, Patent Document 1 discloses a technology that employs a heating method called hot gas heating that utilizes the compressor of a heat pump when the outside temperature is extremely low. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-075844 A Summary of the Invention [Problem to be solved by the invention]

[0004] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an air conditioner for a vehicle that has a quick heating property. [Means for solving the problem]

[0005] According to one aspect of the present invention, an air conditioner for a vehicle includes a compressor, a heater core configured to heat air to be supplied into a vehicle interior, a pressure reducing device, a low-temperature side heat exchanger configured to exchange heat with a refrigerant, and a low-temperature side heat exchanger bypass flow path that bypasses the low-temperature side heat exchanger, and includes a path configured to circulate the refrigerant between the compressor, the heater core, the pressure reducing device, and the low-temperature side heat exchanger bypass flow path, and a refrigerant that has passed through the compressor. the control device is configured to switch and control the refrigerant circuit and is capable of control in a hot gas heating mode in which a portion of the refrigerant that has passed through the compressor is caused to flow to the heater core and the remaining refrigerant is caused to flow to the bypass path, and in the hot gas heating mode, the control device is capable of control so as to circulate the refrigerant through the compressor, the heater core, the pressure reducing device, and the low-temperature side heat exchanger bypass flow path to bypass the low-temperature side heat exchanger. Effect of the Invention

[0006] According to the present invention, a vehicle air conditioner having good quick heating properties can be provided. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an outline of a configuration example of a vehicle air conditioner according to one embodiment, and is a diagram showing an example of a state of the vehicle air conditioner when a hot gas heating mode is executed. [Diagram 2] FIG. 2 is a block diagram showing an example of a configuration related to a control device of a vehicle air conditioner. [Diagram 3] FIG. 3 is a flowchart showing a first example of a process relating to the hot gas heating mode in the vehicle air conditioner. [Figure 4] FIG. 4 is a flowchart showing a second example of the process relating to the hot gas heating mode in the vehicle air conditioner. [Diagram 5]FIG. 5 is a diagram showing an outline of a configuration example of a vehicle air conditioner, and is a diagram showing an example of one state in a second example of processing related to the hot gas heating mode. [Figure 6] FIG. 6 is a diagram showing an outline of a configuration example of a vehicle air conditioner, and is a diagram showing an example of one state in a third example of processing related to the hot gas heating mode. [Figure 7] FIG. 7 is a flowchart showing a third example of the process relating to the hot gas heating mode in the vehicle air conditioner. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [Configuration of vehicle air conditioning system] Overview of Vehicle Air Conditioning System The present embodiment relates to a vehicle air conditioner having a refrigerant circuit and a heat medium circuit. The vehicle air conditioner of the present embodiment is mounted on an electric vehicle and is configured to improve quick heating performance.

[0009] 1 is an explanatory diagram showing an outline of a configuration example of a vehicle air conditioner 1 according to this embodiment. The vehicle air conditioner 1 includes a refrigerant circuit 10 configured to circulate a refrigerant. The refrigerant may be, but is not limited to, hydrofluoroolefin or the like. The vehicle air conditioner 1 also includes a battery temperature control circuit 40 configured to circulate a heat medium fluid such as a coolant.

[0010] The vehicle air conditioner 1 also includes an HVAC (Heating, Ventilation, and Air Conditioning) unit 100, which is an air conditioning unit. The vehicle air conditioner 1 also includes a control device 200 (see FIG. 2) that controls the operation of various sensors and each part of the vehicle air conditioner 1. The operation of the vehicle air conditioner 1 is controlled based on the detection values ​​of the various sensors, various requests, etc.

[0011] <Refrigerant circuit> The refrigerant circuit 10 includes a compressor 11 that compresses a gaseous refrigerant to a high temperature and high pressure and then discharges it, a heater core 12 that is housed in a case 110 of the HVAC unit 100 and heats the air to be supplied to the vehicle interior, pressure reducing devices 13a, 13c, 13d, and 13e such as expansion valves that expand the liquid refrigerant to a low pressure, a low-temperature side heat exchanger 14 that evaporates the low-temperature and low-pressure liquid refrigerant to absorb heat, an accumulator 15, a cooler core 16 that is housed in the case 110 of the HVAC unit 100 and cools the air to be supplied to the vehicle interior, and a radiator 17 as an exterior heat exchanger. The refrigerant circuit 10 is configured to function as a heat pump that circulates the refrigerant and repeats compression, condensation, expansion, and evaporation.

[0012] In the low-temperature side heat exchanger 14, the refrigerant exchanges heat with a heat medium circulating in the battery temperature control circuit 40. In the example shown in the figure, the low-temperature side heat exchanger 14 includes a refrigerant passage 14a through which the refrigerant circulating in the refrigerant circuit 10 passes, and a heat medium passage 14b through which the heat medium circulating in the battery temperature control circuit 40 passes.

[0013] The elements of the refrigerant circuit 10 are connected by refrigerant flow paths 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10j, 10k, 10m, 10n, 10p, 10q, 10r, 10s, 10t, 10u, 10v, and 10w.

[0014] A discharge side 11a of the compressor 11 is connected to an inlet side 12a of a heater core 12 via a refrigerant flow path 10a connected thereto, a branch point 18a, and a refrigerant flow path 10b downstream of the branch point 18a.

[0015] A discharge side 11a of the compressor 11 is connected to an inlet side 15a of an accumulator 15 via a refrigerant flow path 10a, a branch point 18a, a refrigerant flow path 10c, a refrigerant flow path 10d, a junction 19a, a refrigerant flow path 10e, a junction 19b, and a downstream refrigerant flow path 10f, all of which are connected to the discharge side 11a. A pressure reducing device 13a is provided on the path of the refrigerant flow path 10c as a bypass pressure reducing device.

[0016] An outlet side 15b of the accumulator 15 is connected to a suction side 11b of the compressor 11 via a refrigerant flow path 10g connected thereto.

[0017] The outlet side 12b of the heater core 12 is connected to the inlet side 16a of the cooler core 16 via the refrigerant flow path 10j, the branch point 18c, the refrigerant flow path 10k, the junction 19d, the refrigerant flow path 10m, the branch point 18d, and the downstream refrigerant flow path 10n. A flow path switching valve 20c is provided on the path of the refrigerant flow path 10k. A pressure reducing device 13c is provided on the path of the refrigerant flow path 10n.

[0018] The outlet side 16b of the cooler core 16 is connected to the inlet side 15a of the accumulator 15 via the refrigerant flow paths 10p, the junction 19e, the refrigerant flow paths 10q, the junction 19a, the refrigerant flow paths 10e, the junction 19b, and the downstream refrigerant flow path 10f. A check valve 21b is provided on the path of the refrigerant flow path 10q to prevent the refrigerant from flowing back to the cooler core 16.

[0019] The outlet side 12b of the heater core 12 is connected to an inlet of a refrigerant passage 14a of the low-temperature side heat exchanger 14 via a refrigerant passage 10j, a branch point 18c, a refrigerant passage 10k, a junction 19d, a refrigerant passage 10m, a branch point 18d, and a downstream refrigerant passage 10r, which are connected to the outlet side 12b. A pressure reducing device 13d is installed on the path of the refrigerant passage 10r.

[0020] The outlet of the refrigerant passage 14a of the low-temperature side heat exchanger 14 is connected to an inlet side 15a of the accumulator 15 via a refrigerant flow path 10s connected thereto, a junction 19b, and a refrigerant flow path 10f downstream of the junction 19b.

[0021] An outlet side 12b of the heater core 12 is connected to an inlet side 17a of a radiator 17 via a refrigerant flow path 10j connected thereto, a branch point 18c, and a downstream refrigerant flow path 10t. A pressure reducing device 13e is installed on the path of the refrigerant flow path 10t.

[0022] The outlet side 17b of the radiator 17 is connected to the inlet side 15a of the accumulator 15 via the refrigerant flow path 10u, the branch point 18e, the refrigerant flow path 10v, the junction 19e, the refrigerant flow path 10q, the junction 19a, the refrigerant flow path 10e, the junction 19b, and the refrigerant flow path 10f downstream thereof. A flow path switching valve 20e is provided on the path of the refrigerant flow path 10v.

[0023] The outlet side 17b of the radiator 17 is connected to the inlet side 16a of the cooler core 16 via the refrigerant flow path 10u, the branch point 18e, the refrigerant flow path 10w, the junction 19d, the refrigerant flow path 10m, the branch point 18d, and the downstream refrigerant flow path 10n. A check valve 21c is provided on the path of the refrigerant flow path 10w to prevent the refrigerant from flowing back to the radiator 17.

[0024] The outlet side 17b of the radiator 17 is connected to the inlet of the refrigerant passage 14a of the low-temperature side heat exchanger 14 via the refrigerant flow path 10u, branch point 18e, refrigerant flow path 10w, junction 19d, refrigerant flow path 10m, branch point 18d, and the downstream refrigerant flow path 10r connected thereto.

[0025] <Battery temperature control circuit> The battery temperature control circuit 40 as an in-vehicle heat-generating device temperature control circuit includes the heat medium passage 14b of the low-temperature side heat exchanger 14 described above, and a battery 41 as an example of an in-vehicle heat-generating device. The battery 41 is provided with a battery temperature control unit for controlling the temperature of the battery 41. The battery temperature control circuit 40 can be used to adjust the temperature of the battery 41.

[0026] Note that a configuration similar to that of the battery temperature control circuit 40 can also be applied to other in-vehicle device temperature control circuits having an in-vehicle device temperature control unit for controlling the temperature of other in-vehicle devices that require temperature control in a similar manner, not limited to the battery.

[0027] In the example shown in the figure, the elements of the battery temperature control circuit 40 are connected by heat medium flow paths 40a, 40b. The inlet side 41a of the battery 41 is connected to the outlet of the heat medium passage 14b of the low-temperature side heat exchanger 14 by the heat medium flow path 40a. The outlet side 41b of the battery 41 is connected to the inlet of the heat medium passage 14b of the low-temperature side heat exchanger 14 by the heat medium flow path 40b.

[0028] On the path of the heat medium flow path 40b, a circulation pump P40 and a heat medium heater 42 are installed in this order from the upstream side. The heat medium can be circulated by the circulation pump P40. The heat medium heater 42 can heat the heat medium. The temperature of the battery 41 can be adjusted using the heat medium. In this way, the battery temperature control circuit 40, which is an in-vehicle heat-generating device temperature control circuit, is a heat medium circuit in which the heat medium circulates.

[0029] <HVAC unit> The heater core 12 and the cooler core 16 of the refrigerant circuit 10 are housed in a case 110 of the HVAC unit 100. The case 110 forms the outer shell of the HVAC unit 100, and also forms an air flow passage 120 therein.

[0030] The HVAC unit 100 also has an intake unit 130. The intake unit 130 closes either an outside air intake port that introduces outside air in the vehicle cabin or an inside air intake port that introduces inside air in the vehicle cabin, and switches the air introduced into the case 110 between outside air (outside air intake) and inside air (inside air circulation). The HVAC unit 100 also has a blower 140 installed adjacent to the intake unit 130 so that the air introduced into the case 110 is sent to the air flow passage 120.

[0031] The cooler core 16 is installed at the upstream side of the air flow passage 120. A heater core passage and a bypass passage are formed in parallel at the downstream side of the air flow passage 120. The heater core 12 is provided in the heater core passage. Therefore, when air introduced into the case 110 is guided to the heater core passage, the air is ventilated to the cooler core 16 and then ventilated to the heater core 12. On the other hand, when air introduced into the case 110 is guided to the bypass passage, the air is ventilated to the cooler core 16 and then bypasses the heater core 12. The ratio of the air passing through the heater core passage and the air passing through the bypass passage is adjusted by the air mix damper 150.

[0032] Control Device FIG. 2 is an explanatory diagram showing an outline of a configuration example of the control device 200 of the vehicle air conditioner 1 according to this embodiment.

[0033] The control device 200 controls the operation of various sensors and each part of the vehicle air conditioner 1. The operation of the vehicle air conditioner 1 is controlled by the control device 200 based on detection values ​​of various sensors, various requests, etc. The control device 200 is an air conditioning ECU (Electronic Control Unit) for executing various control modes of the vehicle air conditioner 1. The various control modes executed by the control device 200 include a hot gas heating mode that executes hot gas heating.

[0034] Detection information from various sensors is input to the control device 200. In the hot gas heating mode, detection information from a blower temperature sensor 210, an outside air temperature sensor 220, a refrigerant temperature sensor 230, a refrigerant pressure sensor 240, and a heat medium temperature sensor 250 is input to the control device 200.

[0035] The control device 200 controls the operation of the flow path switching valve 20, including the above-mentioned flow path switching valves 20c, 20e, based on detection information from various sensors, to open and close the flow path switching valve 20, thereby selecting a path in the refrigerant circuit 10. In addition, while selecting a path, the control device 200 controls the operation of the compressor 11, the blower 140, the air mix damper 150, the circulation pump P40, and the pressure reducing devices 13, including the above-mentioned pressure reducing devices 13a, 13c, 13d, and 13e, to control the amount of heat released from the refrigerant.

[0036] [Operation of vehicle air conditioning system] A specific operation of the vehicle air conditioner 1 according to this embodiment will be described with reference to the respective drawings.

[0037] <Hot gas heating mode> 1 shows a basic state of a vehicle air conditioner 1 when the outside air temperature is extremely low. At this time, the vehicle interior is heated by executing hot gas heating.

[0038] In the hot gas heating mode, the controller 200 fully closes the pressure reducing devices 13c and 13e and opens the flow path switching valve 20c.

[0039] As a result, the refrigerant discharged from the compressor 11 flows into the refrigerant flow paths 10a and 10b and passes through the heater core 12. The refrigerant that has passed through the heater core 12 flows into the refrigerant flow paths 10j, 10k, 10m, and 10r and passes through the refrigerant passage 14a of the low-temperature side heat exchanger 14. The refrigerant that has passed through the refrigerant passage 14a of the low-temperature side heat exchanger 14 flows into the refrigerant flow paths 10s and 10f and flows into the accumulator 15. The refrigerant that has flowed into the accumulator 15 flows into the refrigerant flow path 10g and then flows into the compressor 11. In other words, the refrigerant flow paths 10a, 10b, 10j, 10k, 10m, 10r, 10s, 10f, and 10g form a circulation path through which the refrigerant that has passed through the compressor 11 passes through the heater core 12.

[0040] In addition, the refrigerant discharged from the compressor 11 flows into the refrigerant flow paths 10a, 10c, 10d, 10e, and 10f and then flows into the accumulator 15. The refrigerant that flows into the accumulator 15 flows into the refrigerant flow path 10g and then flows into the compressor 11. In other words, the refrigerant flow paths 10a, 10c, 10d, 10e, 10f, and 10g form a bypass path through which the refrigerant that has passed through the compressor 11 detours without passing through the heater core 12.

[0041] The control device 200 adjusts the throttling amount of the pressure reducing device 13a to cause a portion of the refrigerant discharged from the compressor 11 to flow to the heater core 12 and the remaining refrigerant to flow to the bypass path. As a result, the vehicle interior is heated by the heat of the refrigerant dissipated in the heater core 12. In addition, the refrigerant flowing through the bypass path has a higher temperature when it returns to the suction side 11b of the compressor 11 than the refrigerant passing through the heater core 12. As a result, in the hot gas heating mode, the temperature of the refrigerant discharged from the compressor 11 can be increased to maintain the heating capacity.

[0042] Here, since each part of the battery temperature control circuit 40 is also exposed to the outside air, the temperature of the heat medium in the battery temperature control circuit 40 and the temperature of the low-temperature side heat exchanger 14 are generally low during startup when the outside air temperature is low. For this reason, when the refrigerant passes through the refrigerant passage 14a of the low-temperature side heat exchanger 14, the heat of the refrigerant may be dissipated to the housing of the low-temperature side heat exchanger 14 or the heat medium in the battery temperature control circuit 40. Such heat dissipation may hinder the required pressure increase of the refrigerant. Therefore, in the vehicle air conditioner 1 of this embodiment, the operation of the refrigerant circuit 10 is adjusted according to the temperature of the heat medium in the battery temperature control circuit 40. For example, in the hot gas heating mode, when the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 does not satisfy a predetermined condition, the control device 200 restricts the refrigerant flowing into the low-temperature side heat exchanger 14. Several specific examples of the operation of restricting the refrigerant flowing into the low-temperature side heat exchanger 14 are considered, and they will be described below.

[0043] (First example) 3 is a flowchart showing a first example of a specific control process procedure of the control device 200 at the start of the hot gas heating mode. The first example will be described with reference to the flowchart of FIG. 3 and the circuit diagram of FIG.

[0044] When the outside air temperature is extremely low, the control device 200 activates the hot gas heating mode. At this time, the control device 200 fully closes the pressure reducing devices 13c and 13e.

[0045] In step S101, the control device 200 determines whether the temperature of the heat medium in the battery temperature control circuit 40 is higher than the temperature of the refrigerant in the refrigerant circuit 10. For example, the respective temperatures at the inlet side of the low-temperature side heat exchanger 14 may be acquired as the temperatures of the heat medium and the refrigerant. During startup when the outside air temperature is extremely low, the temperature of the heat medium is low and is often lower than the temperature of the refrigerant. When the temperature of the heat medium is not higher than the temperature of the refrigerant, the process proceeds to step S102.

[0046] In step S102, the control device 200 determines whether the temperature of the heat medium is higher than the outside air temperature by a predetermined temperature. Here, the predetermined temperature can be set appropriately and may be changed according to various conditions. At the time of start-up, the heat medium temperature is often the outside air temperature. When the temperature of the heat medium is not higher than the outside air temperature by a predetermined temperature, the process proceeds to step S103.

[0047] In step S103, the control device 200 closes the flow path switching valve 20c. As a result, the refrigerant does not flow toward the heater core 12, and therefore does not flow toward the low-temperature side heat exchanger 14. At this time, all of the refrigerant that has passed through the compressor 11 passes through the refrigerant flow paths 10a, 10c, 10d, 10e, 10f, and 10g, and then passes through a bypass path that bypasses the heater core 12. As all of the refrigerant passes through the bypass path, the pressure of the refrigerant rises quickly. As a result, the start-up time of the hot gas operation is shortened.

[0048] In step S104, the control device 200 determines whether or not to continue the hot gas heating mode based on various conditions. If the hot gas heating mode is to be continued, the process returns to step S101. That is, it is repeatedly determined whether or not the temperature of the heat medium is higher than the refrigerant temperature and whether or not it is higher than the outside air temperature by a predetermined temperature. When the temperature of the heat medium is equal to or lower than the refrigerant temperature and is not higher than the outside air temperature by a predetermined temperature, the use of the bypass route continues.

[0049] Eventually, the temperature of the heat medium also rises due to the operation of on-board heat-generating devices such as the battery 41 and the function of the heat medium heater 42. When it is determined in step S102 that the temperature of the heat medium is higher than the outside air temperature by a predetermined temperature, the process proceeds to step S105.

[0050] In step S105, the control device 200 opens the flow path switching valve 20c. As a result, the refrigerant flows through the heater core 12. That is, the refrigerant flow paths 10a, 10b, 10j, 10k, 10m, 10r, 10s, 10f, and 10g form a circulation path in which the refrigerant that has passed through the compressor 11 passes through the heater core 12 and the low-temperature side heat exchanger 14. The control device 200 adjusts the throttling amount of the pressure reducing device 13a to allow a portion of the refrigerant discharged from the compressor 11 to flow through the heater core 12 and the remaining refrigerant to flow through the bypass path.

[0051] At this time, the refrigerant flows through the heater core 12, and the vehicle interior can be heated. The control device 200 operates the blower 140, and the heat of the refrigerant dissipated by the heater core 12 can be used to heat the interior of the vehicle. The refrigerant flows through the low-temperature side heat exchanger 14. Since the temperature of the refrigerant is equal to or higher than the temperature of the heat medium, the heat of the refrigerant is dissipated to the heat medium side in the low-temperature side heat exchanger 14. However, since the temperature of the heat medium is higher than the outside air temperature by a predetermined temperature, the degree of this heat dissipation is not so great. In addition, the temperature of the refrigerant flowing through the bypass path is higher when it returns to the suction side 11b of the compressor 11 than the refrigerant passing through the heater core 12. As a result, in the hot gas heating mode, the temperature of the refrigerant discharged from the compressor 11 can be increased to maintain the heating capacity.

[0052] In step S106, the control device 200 stops the circulation pump P40, taking into consideration the amount of heat dissipated from the refrigerant to the heat medium. By stopping the circulation pump P40, it is possible to suppress heat dissipation from the refrigerant to the heat medium. If the battery temperature control circuit 40 requires circulation of the heat medium, the circulation pump P40 may be operated. Furthermore, if the battery temperature control circuit 40 has a switchable flow path, the flow path may be switched as appropriate.

[0053] Next, in step S104, the control device 200 determines whether or not to continue the hot gas heating mode based on various conditions. If the hot gas heating mode is to be continued, the process returns to step S101. That is, it is repeatedly determined whether or not the temperature of the heat medium is higher than the refrigerant temperature and whether or not it is higher than the outside air temperature by a predetermined temperature. When the temperature of the heat medium is equal to or lower than the refrigerant temperature and higher than the outside air temperature by a predetermined temperature, the states of steps S105 and S106 are continued.

[0054] For example, if it is necessary to start heating the vehicle interior early, the predetermined value used in the determination in step S102 can be reduced to allow the process to proceed to steps S105 and S106 early, and for example, if it is desired to further suppress heat radiation from the refrigerant in the low-temperature side heat exchanger 14, the predetermined value used in the determination in step S102 can be increased to allow the process in step S103 to continue for a longer period. Also, although an example has been shown in which the temperature of the refrigerant is not taken into consideration in the determination in step S102, the temperature of the refrigerant may also be used in the determination.

[0055] As described above, the flow of the refrigerant into the low-temperature side heat exchanger 14 is adjusted according to the temperature of the heat medium, so that the heat radiation from the refrigerant to the heat medium is suppressed. As a result, the start-up time of the hot gas operation is shortened.

[0056] Eventually, the temperature of the heat medium may further increase due to the operation of on-board heat-generating devices such as the battery 41 and the function of the heat medium heater 42. When it is determined in step S101 that the temperature of the heat medium is higher than the temperature of the refrigerant, the process proceeds to step S107.

[0057] In step S107, the control device 200 opens the flow path switching valve 20c as in step S105, and causes the refrigerant to flow through the heater core 12 and the low-temperature side heat exchanger 14. In step S108, the control device 200 operates the circulation pump P40. Since the temperature of the heat medium is higher than that of the refrigerant, the refrigerant absorbs heat from the heat medium. As a result, the start-up time of the hot gas operation is shortened. In addition, since the refrigerant absorbs heat from the heat medium, the rotation speed of the compressor 11 can be reduced accordingly, which realizes reduction in noise and power consumption.

[0058] Next, in step S104, the control device 200 determines whether or not to continue the hot gas heating mode based on various conditions. If the hot gas heating mode is to be continued, the process returns to step S101, and the hot gas heating mode is continued. If the hot gas heating mode is not to be continued, the process of the hot gas heating mode ends.

[0059] By the above-mentioned operation, the refrigerant pressure rises quickly when the hot gas operation starts, and the target blowing temperature by the HVAC unit 100 can be quickly achieved. In other words, quick heating can be realized. In addition, noise generation and power consumption by the compressor 11 can be suppressed.

[0060] The above example is a case where the temperature of the heat medium is used for the determination, but the present invention is not limited thereto. For example, the temperature difference between the temperature of the heat medium at the inlet side and the temperature of the heat medium at the outlet side of the low-temperature side heat exchanger 14 may be used for the determination. When the refrigerant flows through the low-temperature side heat exchanger 14 and the heat of the refrigerant is dissipated to the heat medium, the temperature of the heat medium at the outlet side becomes higher than the temperature of the heat medium at the inlet side of the low-temperature side heat exchanger 14, and the greater the degree of heat dissipation, the greater the temperature difference becomes. Therefore, when the temperature of the heat medium at the outlet side becomes higher than the temperature of the heat medium at the inlet side of the low-temperature side heat exchanger 14 by a predetermined value, the inflow of the refrigerant into the low-temperature side heat exchanger 14 may be restricted or the operation of the circulation pump P40 may be stopped.

[0061] In the first example, when the heat medium of the battery temperature control circuit 40 has cooled to the same degree as the outside air temperature, the above-mentioned order is followed. On the other hand, the temperature of the heat generating device such as the battery 41 may be higher than the outside air temperature or the refrigerant temperature, for example, when the battery 41 is being charged before starting, or when not much time has passed since the operation was stopped and the heat medium has not yet cooled. In such a case, in the first example, the refrigerant flows through the low-temperature side heat exchanger 14 immediately upon starting, and in some cases, the refrigerant absorbs heat from the heat medium of the battery temperature control circuit 40. As a result, the pressure of the refrigerant rises quickly when hot gas operation starts, and high speed heating is achieved.

[0062] (Second example) In the first example described above, when the temperature of the heat medium in the battery temperature control circuit 40 is very low, the refrigerant is made to bypass the heater core 12 and the low-temperature side heat exchanger 14 and only the bypass path is used. In the second example, the refrigerant that has passed through the heater core 12 is made to bypass the low-temperature side heat exchanger 14 and pass through the cooler core 16. FIG. 4 is a flowchart showing a second example of a specific control process procedure of the control device 200 at the start of the hot gas heating mode. The second example will be described with reference to the flowchart in FIG. 4 and the circuit diagram in FIG. 5. Note that some of the descriptions common to the first example will be omitted. The above descriptions may also be applied to the second example to the extent that there is no contradiction.

[0063] When the outside air temperature is extremely low, the control device 200 activates the hot gas heating mode. At this time, the control device 200 fully closes the pressure reducing device 13e and opens the flow path switching valve 20c.

[0064] In step S201, the control device 200 determines whether or not the temperature of the heat medium in the battery temperature adjustment circuit 40 is higher than the temperature of the refrigerant in the refrigerant circuit 10. When the temperature of the heat medium is not higher than the temperature of the refrigerant, the process proceeds to step S202.

[0065] In step S202, the control device 200 determines whether the temperature of the heat medium is higher than the outside air temperature by more than a predetermined temperature. When the temperature of the heat medium is not higher than the outside air temperature by more than the predetermined temperature, the process proceeds to step S203.

[0066] In step S203, the control device 200 closes the pressure reducing device 13d and opens the pressure reducing device 13c. As a result, as shown in FIG. 5, the refrigerant does not flow toward the low-temperature side heat exchanger 14 but flows through the cooler core 16. That is, the refrigerant flow paths 10a, 10b, 10j, 10k, 10m, 10n, 10p, 10q, 10e, 10f, and 10g form a circulation path in which the refrigerant that has passed through the compressor 11 passes through the heater core 12 and the cooler core 16. The control device 200 adjusts the throttling amount of the pressure reducing device 13a to allow a portion of the refrigerant discharged from the compressor 11 to flow through the heater core 12 and the cooler core 16, and allows the remaining refrigerant to flow through the bypass path.

[0067] In step S204, the control device 200 stops the blower 140. This is because it is not appropriate for the operation of the refrigerant circuit 10 to blow air to the cooler core 16 and the heater core 12 in a state in which refrigerant flows through both the heater core 12 on the upstream side of the pressure reducing device 13c and the cooler core 16 on the downstream side.

[0068] In this way, the refrigerant does not flow through the low-temperature side heat exchanger 14, which is as cold as the outside air temperature. Therefore, the refrigerant does not radiate heat to the housing of the low-temperature side heat exchanger 14 or the heat medium. For example, when starting operation again after parking for a relatively short time, the interior of the vehicle where the cooler core 16 is located may be hotter than the motor room where the low-temperature side heat exchanger 14 is located. In such a case, the effect of flowing the refrigerant through the cooler core 16 as in this example is remarkable. According to this example, by bypassing the low-temperature low-temperature side heat exchanger 14, the pressure of the refrigerant is likely to increase, and the start-up time of hot gas operation may be shortened. Also, when the temperature inside the vehicle where the cooler core 16 is located is as cold as the motor room where the low-temperature side heat exchanger 14 is located, the refrigerant flowing through the cooler core 16 may radiate heat to the same extent as if it had flowed through the low-temperature side heat exchanger 14. However, the inside of the HVAC unit 100 is preheated by the heat radiated from the cooler core 16. Such an operation can be called a preparatory operation of the HVAC unit 100. In this case, as described later, a drop in refrigerant pressure caused by heat radiation from the heater core 12 when the blower 140 starts operating can be suppressed, and the start-up time of hot gas operation can be shortened. In other words, heat is used efficiently overall.

[0069] In step S205, the control device 200 determines whether to continue the hot gas heating mode based on various conditions. When the hot gas heating mode is to be continued, the process returns to step S201. That is, it is repeatedly determined whether the temperature of the heat medium is higher than the refrigerant temperature and whether it is higher than the outside air temperature by a predetermined temperature. When the temperature of the heat medium is equal to or lower than the refrigerant temperature and is not higher than the outside air temperature by a predetermined temperature, the use of the flow path passing through the cooler core 16 is continued.

[0070] When it is determined in step S202 that the temperature of the heat medium is higher than the outside air temperature by a predetermined temperature, the process proceeds to step S206. In step S206, the control device 200 closes the pressure reducing device 13c and opens the pressure reducing device 13d. As a result, as shown in FIG. 1, the refrigerant does not flow toward the cooler core 16 but flows through the low-temperature side heat exchanger 14. That is, the refrigerant flow paths 10a, 10b, 10j, 10k, 10m, 10r, 10s, 10f, and 10g form a circulation path in which the refrigerant that has passed through the compressor 11 passes through the heater core 12 and the low-temperature side heat exchanger 14. The control device 200 adjusts the throttling amount of the pressure reducing device 13a to flow a part of the refrigerant discharged from the compressor 11 to the heater core 12 and the remaining refrigerant to flow through the bypass path.

[0071] In step S207, the control device 200 operates the blower 140 to enable indoor heating by the heat of the refrigerant dissipated in the heater core 12. As described above, the heat dissipated when the refrigerant was flowing through the cooler core 16 can also be utilized during this air conditioning operation.

[0072] The refrigerant flows through low-temperature side heat exchanger 14. Because the temperature of the refrigerant is equal to or higher than the temperature of the heat medium, the heat of the refrigerant is dissipated to the heat medium side in low-temperature side heat exchanger 14, but because the temperature of the heat medium is higher than the outside air temperature by a predetermined temperature, the degree of this heat dissipation is not that great. On the other hand, the refrigerant flowing through the bypass path has a higher temperature when it returns to suction side 11b of compressor 11 than the refrigerant passing through heater core 12. As a result, in hot gas heating mode, the temperature of the refrigerant discharged from compressor 11 can be increased to maintain heating capacity.

[0073] In step S208, the control device 200 stops the circulation pump P40 in consideration of the amount of heat dissipation from the refrigerant to the heat medium. By stopping the circulation pump P40, it is possible to suppress the heat dissipation from the refrigerant to the heat medium.

[0074] Next, in step S205, the control device 200 determines whether to continue the hot gas heating mode based on various conditions, and if the hot gas heating mode is to be continued, the process returns to step S201. If the temperature of the heat medium is equal to or lower than the refrigerant temperature and is higher than the outside air temperature by a predetermined temperature, the states of steps S206 to S208 continue.

[0075] Since the flow of the refrigerant into the low-temperature side heat exchanger 14 is adjusted according to the temperature of the heat medium, heat radiation from the refrigerant to the heat medium is suppressed, and as a result, the start-up time of the hot gas operation is shortened.

[0076] When it is determined in step S201 that the temperature of the heat medium is higher than the temperature of the refrigerant, the process proceeds to step S209. In step S209, the control device 200 causes the refrigerant to flow through the heater core 12 and the low-temperature side heat exchanger 14. In step S210, the control device 200 operates the circulation pump P40. Since the temperature of the heat medium is higher than the temperature of the refrigerant, the refrigerant absorbs heat from the heat medium. As a result, the start-up time of the hot gas operation is shortened. In addition, since the refrigerant absorbs heat from the heat medium, the rotation speed of the compressor 11 can be reduced accordingly, which realizes reduction in noise and power consumption.

[0077] Next, in step S205, the control device 200 determines whether or not to continue the hot gas heating mode based on various conditions. If the hot gas heating mode is to be continued, the process returns to step S201, and the hot gas heating mode is continued. If the hot gas heating mode is not to be continued, the process of the hot gas heating mode ends.

[0078] By the above-mentioned operation, the refrigerant pressure rises quickly when the hot gas operation starts, and the target blowing temperature by the HVAC unit 100 can be quickly achieved. In other words, quick heating can be realized. In addition, noise generation and power consumption by the compressor 11 can be suppressed.

[0079] (Third example) In the above-mentioned second example, when the temperature of the heat medium in the battery temperature control circuit 40 is very low, the refrigerant that has passed through the heater core 12 is passed through the cooler core 16, bypassing the low-temperature side heat exchanger 14. In a third example, as shown in Fig. 6, the refrigerant circuit 10 is provided with a refrigerant flow path 10x that bypasses the low-temperature side heat exchanger 14.

[0080] More specifically, a three-way valve V31 is provided in a refrigerant flow path 10r leading from the pressure reducing device 13d to the refrigerant passage 14a of the low-temperature side heat exchanger 14. One side of the three-way valve V31 to which the refrigerant flow path 10r is connected connects the refrigerant flow path 10r to a refrigerant flow path 10y in which the low-temperature side heat exchanger 14 is arranged. The other side of the three-way valve V31 to which the refrigerant flow path 10r is connected connects the refrigerant flow path 10r to a junction 19f of a refrigerant flow path 10s leading to the accumulator 15, which is a refrigerant flow path 10x that is a low-temperature side heat exchanger bypass flow path that bypasses the low-temperature side heat exchanger 14. A check valve 21d is provided on the path of the refrigerant flow path 10y connecting the low-temperature side heat exchanger 14 and the junction 19f to prevent the refrigerant from flowing back to the low-temperature side heat exchanger 14.

[0081] Fig. 7 is a flowchart showing a third example of a specific control processing procedure of the control device 200 when starting up the hot gas heating mode. The third example will be described with reference to the flowchart of Fig. 7 and the circuit diagram of Fig. 6. Note that some of the descriptions common to the first example will be omitted. The above descriptions may also be applied to the third example to the extent that there is no contradiction.

[0082] When the outside air temperature is extremely low, the control device 200 activates the hot gas heating mode. At this time, the control device 200 fully closes the pressure reducing devices 13c and 13e and opens the flow path switching valve 20c.

[0083] In step S301, the control device 200 determines whether or not the temperature of the heat medium in the battery temperature adjustment circuit 40 is higher than the temperature of the refrigerant in the refrigerant circuit 10. When the temperature of the heat medium is not higher than the temperature of the refrigerant, the process proceeds to step S302.

[0084] In step S302, the control device 200 switches the three-way valve V31 so that the refrigerant flows through the refrigerant flow path 10x that bypasses the low-temperature side heat exchanger 14 without flowing through the low-temperature side heat exchanger 14. As a result, as shown in Fig. 6, the refrigerant flow paths 10a, 10b, 10j, 10k, 10m, 10r, 10x, 10s, 10f, and 10g form a circulation path in which the refrigerant that has passed through the compressor 11 passes through the heater core 12 and bypasses the low-temperature side heat exchanger 14. The control device 200 adjusts the throttling amount of the pressure reducing device 13a to cause a portion of the refrigerant discharged from the compressor 11 to flow through the heater core 12 and the remaining refrigerant to flow through the bypass path.

[0085] Because the refrigerant does not flow toward the low-temperature side heat exchanger 14, where the temperature is as low as the outside air temperature, the refrigerant does not dissipate heat to the housing or heat medium of the low-temperature side heat exchanger 14. As a result, the pressure of the refrigerant is likely to increase, and the start-up time of hot gas operation may become shorter.

[0086] In step S303, the control device 200 determines whether or not to continue the hot gas heating mode based on various conditions. When the hot gas heating mode is to be continued, the process returns to step S301. That is, it is repeatedly determined whether or not the temperature of the heat medium is higher than the refrigerant temperature, and when the temperature of the heat medium is equal to or lower than the refrigerant temperature, the refrigerant continues to bypass the low-temperature side heat exchanger 14.

[0087] When it is determined in step S301 that the temperature of the heat medium is higher than the temperature of the refrigerant, the process proceeds to step S304. In step S304, the control device 200 switches the three-way valve V31 so as to allow the refrigerant to flow to the low-temperature side heat exchanger 14. As a result, the refrigerant flow paths 10a, 10b, 10j, 10k, 10m, 10r, 10y, 10s, 10f, and 10g form a circulation path in which the refrigerant that has passed through the compressor 11 passes through the heater core 12 and the low-temperature side heat exchanger 14. The control device 200 adjusts the throttling amount of the pressure reducing device 13a to allow a portion of the refrigerant discharged from the compressor 11 to flow to the heater core 12 and the remaining refrigerant to flow to the bypass path.

[0088] In step S305, the control device 200 operates the circulation pump P40. Since the temperature of the heat medium is higher than the temperature of the refrigerant, the refrigerant absorbs heat from the heat medium. As a result, the start-up time of the hot gas operation is shortened.

[0089] Next, in step S303, the control device 200 determines whether or not to continue the hot gas heating mode based on various conditions. If the hot gas heating mode is to be continued, the process returns to step S301, and the hot gas heating mode is continued. If the hot gas heating mode is not to be continued, the process of the hot gas heating mode ends.

[0090] By the above-mentioned operation, the refrigerant pressure rises quickly when the hot gas operation starts, and the target blowing temperature by the HVAC unit 100 can be quickly achieved. In other words, quick heating can be realized. In addition, noise generation and power consumption by the compressor 11 can be suppressed.

[0091] The operations of the first to third examples described above can be combined as appropriate. That is, depending on conditions such as the temperature of the heat medium in the battery temperature control circuit 40 and the pressure and temperature of the refrigerant, the control device 200, for example, causes the refrigerant to bypass the heater core 12, to flow through the heater core 12 and the cooler core 16, to flow through the heater core 12 and the low-temperature side heat exchanger 14, or to flow through the heater core 12 and the low-temperature side heat exchanger 14. The control device 200 also circulates or does not circulate the heat medium in the battery temperature control circuit 40. The control device 200 can combine these as appropriate to speed up the start-up of the hot gas operation and achieve fast warm-up.

[0092] [About vehicle air conditioning systems] The vehicle air conditioner 1 of this embodiment can provide the following advantages.

[0093] (a1) The vehicle air conditioner 1 includes a compressor 11, a heater core 12 configured to heat air supplied to the vehicle interior, a pressure reducing device 13, and a low-temperature side heat exchanger 14 configured to exchange heat between a heat medium that exchanges heat with an on-board heat generating device and a refrigerant, and is equipped with a refrigerant circuit 10 having a path configured to circulate the refrigerant between the compressor 11, the heater core 12, the pressure reducing device 13d, and the low-temperature side heat exchanger 14, and a bypass path in which the refrigerant that has passed through the compressor 11 bypasses the heater core 12 and flows into the suction side of the compressor. The vehicle air conditioner 1 further includes a heat medium circuit, such as a battery temperature control circuit 40, configured to circulate a heat medium between an on-board heat generating device such as a battery 41 and the low-temperature side heat exchanger 14, and a control device 200 that is configured to switch and control the refrigerant circuit 10 and can control in a hot gas heating mode in which a part of the refrigerant that has passed through the compressor 11 flows to the heater core 12 and the remaining refrigerant flows to the bypass path. In the hot gas heating mode, when the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 does not satisfy a predetermined condition, the control device 200 restricts the inflow of refrigerant into the low-temperature side heat exchanger 14.

[0094] As a result, the vehicle air conditioner 1 of this embodiment can shorten the time until the target heating capacity is reached. For example, when the temperature of the refrigerant flowing through the low-temperature side heat exchanger 14 is higher than the temperature of the heat medium flowing through the low-temperature side heat exchanger 14, the refrigerant dissipates heat to the heat medium. In such a case, the temperature of the refrigerant on the suction side of the compressor 11 drops, the state of the refrigerant does not become appropriate easily, and the time until the target heating capacity is reached becomes longer. In response to this, the vehicle air conditioner 1 of this embodiment restricts the inflow of the refrigerant into the low-temperature side heat exchanger 14 until the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 becomes higher than the temperature of the refrigerant flowing through the low-temperature side heat exchanger 14. This prevents heat dissipation from the refrigerant to the heat medium, suppresses a temperature drop of the refrigerant, and improves the temperature rise of the refrigerant. As a result, the time until the target heating capacity is reached can be shortened, and the quick heating performance can be improved.

[0095] (a2) For example, when the hot gas heating mode is started, the controller 200 restricts the inflow of refrigerant into the low-temperature side heat exchanger 14 until the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 exceeds a predetermined reference temperature.

[0096] As a result, the vehicle air conditioner 1 of this embodiment can shorten the time it takes to reach the target heating capacity at the start of the hot gas heating mode. At the start, it is assumed that the entire system is at a temperature close to the outside air temperature. The vehicle air conditioner 1 of this embodiment is particularly effective at the start. The above reference temperature may be a predetermined temperature, the temperature of the refrigerant flowing through the low-temperature side heat exchanger 14, or a value that is a predetermined temperature higher than the outside air temperature.

[0097] (a3) A heat medium circuit such as the battery temperature adjustment circuit 40 may further include a heat medium heating device 42 configured to heat the heat medium.

[0098] By heating the heat medium with the heat medium heater 42, the temperature of the heat medium can be increased in a shorter time. This shortens the time until the temperature of the heat medium satisfies a predetermined condition. In addition, heat radiation from the refrigerant to the heat medium can be further suppressed. As a result, the time until the target heating capacity is reached can be shortened, and the heating speed can be improved.

[0099] (a4) The heat medium circuit may further include a circulation pump P40 configured to circulate the heat medium, and the control device 200 may be configured to control the operation or stop of the circulation pump P40 based on the temperature of the heat medium in the hot gas heating mode.

[0100] When the temperature of the heat medium is lower than the temperature of the refrigerant, heat from the refrigerant may be dissipated to the heat medium in the low-temperature side heat exchanger 14. In this case, this heat dissipation can be suppressed by stopping the circulation pump P40 to stop the circulation of the heat medium. When the temperature of the heat medium is higher than the temperature of the refrigerant, the refrigerant may absorb heat from the heat medium in the low-temperature side heat exchanger 14. In this case, the efficiency of this heat absorption can be improved by circulating the heat medium which operates the circulation pump P40. Either of these contributes to shortening the time required to reach the target heating capacity, and can improve the quick heating performance.

[0101] (a5) When the temperature of the heat medium flowing through the low-temperature side heat exchanger 14, when the control device 200 regulates the inflow of refrigerant into the low-temperature side heat exchanger 14, does not satisfy a predetermined condition, for example, when the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 does not exceed a predetermined reference temperature, when the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 is not higher than the outside air temperature by a predetermined temperature, when the temperature difference between the temperature of the heat medium at the outlet side and the temperature of the heat medium at the inlet side of the low-temperature side heat exchanger 14 exceeds a predetermined value, or when the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 does not exceed the temperature of the refrigerant flowing through the low-temperature side heat exchanger 14.

[0102] The predetermined reference temperature may be set to a temperature low enough to delay the achievement of the target heating capacity, for example. By restricting the inflow of refrigerant into the low-temperature side heat exchanger 14 when the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 does not exceed the predetermined reference temperature, heat loss can be suppressed and delay in the achievement of the target heating capacity can be prevented. In addition, the temperature higher than the outdoor air temperature by a predetermined temperature may be set to a temperature low enough to delay the achievement of the target heating capacity, for example. By restricting the inflow of refrigerant into the low-temperature side heat exchanger 14 when the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 is not higher than the outdoor air temperature by a predetermined temperature, heat loss can be suppressed and delay in the achievement of the target heating capacity can be prevented. When the temperature difference between the temperature of the heat medium at the outlet side and the temperature of the heat medium at the inlet side of the low-temperature side heat exchanger 14 exceeds a predetermined value, there is a large heat dissipation from the refrigerant to the heat medium. By restricting the inflow of refrigerant into the low-temperature side heat exchanger 14 when the temperature difference between the temperature of the heat medium at the outlet side and the temperature of the heat medium at the inlet side of the low-temperature side heat exchanger 14 exceeds a predetermined value, heat loss can be suppressed and delays in achieving the target heating capacity can be prevented. When the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 does not exceed the temperature of the refrigerant flowing through the low-temperature side heat exchanger 14, heat dissipation from the refrigerant to the heat medium can occur. By restricting the inflow of refrigerant into the low-temperature side heat exchanger 14 when the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 does not exceed the temperature of the refrigerant flowing through the low-temperature side heat exchanger 14, heat loss can be suppressed, delays in achieving the target heating capacity can be prevented, and quick heating can be improved.

[0103] (a6) For example, when the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 does not satisfy a predetermined condition, the controller 200 causes all of the refrigerant that has passed through the compressor 11 to flow through the bypass path.

[0104] This makes it possible to suppress heat radiation of the refrigerant in the heater core 12 and also suppress heat radiation of the refrigerant in the low-temperature side heat exchanger 14. As a result, the time required to reach the target heating capacity can be shortened, and the quick heating performance can be improved.

[0105] (a7) The refrigerant circuit 10 includes a cooler core 16 configured to exchange heat with air supplied to the vehicle cabin and arranged downstream of the pressure reducing device 13c, and the control device 200 may flow at least a portion of the refrigerant that has passed through the compressor 11 to the heater core 12, the pressure reducing device 13c and the cooler core 16 when the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 does not satisfy a predetermined condition.

[0106] This allows the refrigerant to dissipate heat in the cooler core 16 instead of the low-temperature side heat exchanger 14, preheating the air in the HVAC unit 100. As a result, the load on the heater core 12 when the blower 140 starts blowing thereafter can be suppressed, and a decrease in the refrigerant pressure on the outlet side of the heater core 12 that may occur when blowing starts can be suppressed. As a result, the time required to reach the target heating capacity can be shortened, and the heating speed can be improved.

[0107] (a8) The refrigerant circuit 10 has a refrigerant flow path 10x that functions as a low-temperature side heat exchanger bypass flow path that bypasses the low-temperature side heat exchanger 14, and the control device 200 may, when the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 does not satisfy a predetermined condition, flow at least a portion of the refrigerant that has passed through the compressor 11 to the heater core 12, the pressure reducing device 13d, and the low-temperature side heat exchanger bypass flow path.

[0108] This makes it possible to suppress the heat radiation of the refrigerant in the low-temperature side heat exchanger 14. As a result, the time required to reach the target heating capacity can be shortened, and the heating speed can be improved.

[0109] (b1) The vehicle air conditioning device 1 includes a compressor 11, a heater core 12 configured to heat the air supplied to the vehicle cabin, a pressure reducing device 13, a cooler core 16 configured to cool the air supplied to the vehicle cabin, and a low-temperature side heat exchanger 14 configured to exchange heat with a refrigerant, and is equipped with a refrigerant circuit 10 having a path configured to circulate the refrigerant between the compressor 11, the heater core 12, the pressure reducing device 13d, and the low-temperature side heat exchanger 14, a path configured to circulate the refrigerant between the compressor 11, the heater core 12, the pressure reducing device 13c, and the cooler core 16, and a bypass path in which the refrigerant that has passed through the compressor 11 bypasses the heater core 12 and flows into the suction side of the compressor 11. The vehicle air conditioner 1 further includes an HVAC unit 100 as an air conditioning unit having a heater core 12, a cooler core 16, and a blower 140 for blowing air into the vehicle interior, and a control device 200 configured to control the operation of the blower 140 and to switch and control the refrigerant circuit 10, and capable of control in a hot gas heating mode in which a part of the refrigerant that has passed through the compressor 11 flows to the heater core 12 and the remaining refrigerant flows to a bypass path. In the hot gas heating mode, the control device 200 is capable of control in a preparatory operation in which the refrigerant is circulated through the compressor 11, the heater core 12, the pressure reducing device 13c, and the cooler core 16, and blowing air by the blower 140 is prohibited.

[0110] As a result, the vehicle air conditioner 1 of this embodiment can shorten the time until the target heating capacity is reached. For example, when the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 is low, the refrigerant dissipates heat to the heat medium. In such a case, the temperature of the refrigerant on the suction side of the compressor 11 drops, the state of the refrigerant does not become appropriate, and the time until the target heating capacity is reached becomes long. In response to this, the vehicle air conditioner 1 of this embodiment prevents heat dissipation from the refrigerant to the heat medium by, for example, suppressing the inflow of the refrigerant into the low-temperature side heat exchanger 14 until the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 becomes high to a certain extent. As a result, the temperature drop of the refrigerant is suppressed, the temperature rise of the refrigerant is improved, the time until the target heating capacity is reached can be shortened, and the quick heating performance can be improved. Furthermore, the refrigerant dissipates heat not in the low-temperature side heat exchanger 14 but in the cooler core 16, and the air in the HVAC unit 100 is preheated. As a result, the load on the heater core 12 when the blower 140 starts blowing thereafter can be suppressed, and a decrease in the pressure of the refrigerant at the outlet side of the heater core 12 that may occur when blowing starts can be suppressed. This also improves the rise in the temperature of the refrigerant, shortens the time it takes to reach the target heating capacity, and improves the quick heating performance. When the refrigerant is flowed through the heater core 12 and the cooler core 16, the blower 140 is stopped so as not to cause a breakdown in the cycle of the refrigerant circuit 10.

[0111] (b2) The control device 200 is capable of controlling air conditioning operation, for example, in hot gas heating mode, by circulating the refrigerant through the compressor 11, the heater core 12, the pressure reducing device 13d, and the low-temperature side heat exchanger 14 after preparatory operation, and then permitting the blower 140 to blow air.

[0112] By changing the refrigerant flow path from the cooler core 16 to the low-temperature side heat exchanger 14 before starting the blower 140, it is possible to suppress a decrease in the temperature of the refrigerant on the suction side of the compressor 11. This makes it possible to avoid a reduction in the hot gas cycle.

[0113] (c1) The vehicle air conditioner 1 includes a compressor 11, a heater core 12 configured to heat air supplied to a vehicle interior, a pressure reducing device 13d, a low-temperature side heat exchanger 14 configured to exchange heat with the refrigerant, and a refrigerant flow path 10x that functions as a low-temperature side heat exchanger bypass flow path that bypasses the low-temperature side heat exchanger 14, and includes a refrigerant circuit having a path configured to circulate the refrigerant between the compressor 11, the heater core 12, the pressure reducing device 13d, and the low-temperature side heat exchanger 14, a path configured to circulate the refrigerant between the compressor 11, the heater core 12, the pressure reducing device 13d, and the low-temperature side heat exchanger bypass flow path, and a bypass path in which the refrigerant that has passed through the compressor 11 bypasses the heater core 12 and flows into the suction side of the compressor 11. The vehicle air conditioner 1 is configured to control the refrigerant circuit 10 by switching it over, and further includes a control device that can control in a hot gas heating mode in which a part of the refrigerant that has passed through the compressor 11 flows to the heater core 12 and the remaining refrigerant flows to the bypass path. In the hot gas heating mode, the control device 200 can control the refrigerant to circulate through the compressor 11, the heater core 12, the pressure reducing device 13d, and the low-temperature side heat exchanger bypass flow path to bypass the low-temperature side heat exchanger 14.

[0114] As a result, the vehicle air conditioner 1 of this embodiment can shorten the time it takes to reach the target heating capacity. For example, when the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 is low, the refrigerant dissipates heat to the heat medium. In such a case, the temperature of the refrigerant on the suction side of the compressor 11 drops, the state of the refrigerant does not become appropriate, and the time it takes to reach the target heating capacity increases. In response to this, the vehicle air conditioner 1 of this embodiment prevents heat dissipation from the refrigerant to the heat medium by, for example, suppressing the inflow of the refrigerant into the low-temperature side heat exchanger 14 until the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 becomes high to a certain extent. As a result, the temperature drop of the refrigerant is suppressed, the temperature rise of the refrigerant is improved, the time it takes to reach the target heating capacity can be shortened, and the quick heating performance can be improved.

[0115] (c2) The refrigerant circuit 10 may further include a check valve 21d provided to prevent the refrigerant that has flowed through the low-temperature side heat exchanger bypass passage from flowing back into the low-temperature side heat exchanger 14.

[0116] This makes it possible to suppress a decrease in the pressure of the refrigerant on the suction side of the compressor 11 that may occur due to the refrigerant flowing back into the low-temperature side heat exchanger 14.

[0117] (c3) The low-temperature side heat exchanger 14 is configured to exchange heat between the refrigerant and a heat medium that exchanges heat with an on-board heat-generating device such as the battery 41, and in the hot gas heating mode, when the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 does not exceed the temperature of the refrigerant, the control device 200 may circulate the refrigerant through the compressor 11, the heater core 12, the pressure reducing device 13d, and the low-temperature side heat exchanger bypass flow path to bypass the low-temperature side heat exchanger 14.

[0118] This makes it possible to suppress heat radiation from the refrigerant in the low-temperature side heat exchanger 14. That is, when the temperature of the heat medium flowing through the low-temperature side heat exchanger 14 is equal to or lower than the temperature of the refrigerant flowing through the low-temperature side heat exchanger 14, the refrigerant will radiation heat to the heat medium. By bypassing the low-temperature side heat exchanger 14 and flowing through the low-temperature side heat exchanger bypass flow path, it is possible to suppress such heat radiation from the refrigerant. As a result, the time until the target heating capacity is reached can be shortened, and quick heating can be improved.

[0119] Although the present invention has been described above by showing preferred embodiments, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention. [Explanation of symbols]

[0120] 1: Vehicle air conditioning system 10: refrigerant circuit, 11: compressor, 12: heater core, 13, 13a, 13c, 13d, 13e: pressure reducing device, 14: low-temperature side heat exchanger, 15: accumulator, 16: cooler core, 17: radiator, 20, 20c, 20e: flow path switching valve 40: battery temperature control circuit, 41: battery, 42: heat medium heating device, P40: circulation pump 100: HVAC unit, 110: case, 120: air flow passage, 140: blower, 150: air mix damper

Claims

1. a refrigerant circuit including a compressor, a heater core configured to heat air to be supplied into a vehicle interior, a pressure reducing device, a low-temperature side heat exchanger configured to exchange heat with a refrigerant, and a low-temperature side heat exchanger bypass flow path that bypasses the low-temperature side heat exchanger, the refrigerant circuit having a path configured to circulate the refrigerant between the compressor, the heater core, the pressure reducing device, and the low-temperature side heat exchanger, a path configured to circulate the refrigerant between the compressor, the heater core, the pressure reducing device, and the low-temperature side heat exchanger bypass flow path, and a bypass path through which the refrigerant that has passed through the compressor bypasses the heater core and flows into a suction side of the compressor; a control device configured to switch and control the refrigerant circuit, and capable of control in a hot gas heating mode in which a part of the refrigerant that has passed through the compressor flows to the heater core and the remaining refrigerant flows to the bypass path; Equipped with The control device is capable of controlling, in the hot gas heating mode, the refrigerant to circulate through the compressor, the heater core, the pressure reducing device, and the low-temperature side heat exchanger bypass flow path to bypass the low-temperature side heat exchanger. Vehicle air conditioning system.

2. 2. The vehicle air conditioning system according to claim 1, wherein the refrigerant circuit further includes a check valve provided to prevent the refrigerant having flowed through the low-temperature side heat exchanger bypass passage from flowing back into the low-temperature side heat exchanger.

3. the low-temperature side heat exchanger is configured to exchange heat between a heat medium that exchanges heat with an in-vehicle heat generating device and the refrigerant, the control device, when the temperature of the heat medium flowing through the low-temperature side heat exchanger does not exceed the temperature of the refrigerant in the hot gas heating mode, causes the refrigerant to circulate through the compressor, the heater core, the pressure reducing device, and the low-temperature side heat exchanger bypass flow path to bypass the low-temperature side heat exchanger.

3. The vehicle air conditioning system according to claim 1 or 2.

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