Air conditioning device for vehicle

Abstract

Provided is a vehicle air-conditioning device having excellent quick heating performance. A vehicle air conditioner (1) is provided with a refrigerant circuit (10). The refrigerant circuit (10) comprises: a compressor (11); a heater core (12) configured so as to heat air supplied into the vehicle interior; a decompression device (13); and a low-temperature-side heat exchanger (14) configured so as to exchange heat between the refrigerant and a heat medium that exchanges heat with the vehicle-mounted heat generating device. The control device (200) restricts the inflow of the refrigerant into the low-temperature-side heat exchanger (14) when the temperature of a heat medium flowing through the low-temperature-side heat exchanger (14) does not satisfy a predetermined condition in a hot-gas heating mode in which a portion 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.

Description

Technical Field

[0001] This invention relates to an automotive air conditioning device. Background Technology

[0002] Air conditioning systems for electric vehicles (EVs) or vehicles with limited heat sources, such as those lacking a combustion system like an engine, are known to use heat pumps. However, when the external gas temperature is extremely low, it becomes difficult for the heat pump to absorb heat, thus reducing its heating efficiency. Therefore, for example, Patent Document 1 discloses a heating method that utilizes the heat from the compressor of a heat pump to heat the gas when the external gas temperature is extremely low.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2023-075844 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] The purpose of this invention is to provide a vehicle air conditioning device with good rapid heating performance.

[0008] Technical solutions adopted to solve technical problems

[0009] According to one aspect of the present invention, an automotive air conditioning device includes: a refrigerant circuit comprising: a compressor; a heater core configured to heat air supplied to the vehicle interior; a pressure reducing device; and a low-temperature side heat exchanger configured to exchange heat between a heat carrier exchanging heat with on-board heating equipment and the refrigerant, and having: a path configured to circulate the refrigerant in the compressor, the heater core, the pressure reducing device, and the low-temperature side heat exchanger; and a bypass path through which the refrigerant bypasses the heater core and flows into the suction side of the compressor. The system includes: a heat carrier circuit configured to allow the heat carrier to circulate between the vehicle-mounted heating device and the low-temperature heat exchanger; and a control device configured to switch and control the refrigerant circuit, enabling control in a hot gas heating mode where a portion of the refrigerant passing through the compressor flows to the heater core and the remaining refrigerant flows to the bypass path. In the hot gas heating mode, the control device restricts the inflow of refrigerant into the low-temperature heat exchanger when the temperature of the heat carrier flowing through the low-temperature heat exchanger does not meet specified conditions.

[0010] Invention Effects

[0011] According to the present invention, a vehicle air conditioning device with good rapid heating performance can be provided. Attached Figure Description

[0012] Figure 1 This is a diagram showing an outline of the structure of an embodiment of a vehicle air conditioning unit, and also a diagram showing an example of the state of the vehicle air conditioning unit when the hot air heating mode is being executed.

[0013] Figure 2 This is a block diagram illustrating an example of the structure of a control device for an automotive air conditioning system.

[0014] Figure 3 This is a flowchart illustrating a first example of the processing related to the hot air heating mode in an automotive air conditioning system.

[0015] Figure 4 This is a flowchart illustrating a second example of the processing related to the hot air heating mode in an automotive air conditioning system.

[0016] Figure 5 This is a diagram showing a structural example of an automotive air conditioning unit, and also a diagram showing an example of a state in a second example of the processing related to the hot air heating mode.

[0017] Figure 6 This is a diagram showing a structural example of an automotive air conditioning unit, and also a diagram showing an example of a state in a third example of the processing related to the hot air heating mode.

[0018] Figure 7 This is a flowchart illustrating a third example of the processing related to the hot air heating mode in an automotive air conditioning system. Detailed Implementation

[0019] [Structure of automotive air conditioning system]

[0020] <Overview of automotive air conditioning systems>

[0021] This embodiment relates to an automotive air conditioning system having a refrigerant circuit and a heat carrier circuit. The automotive air conditioning system of this embodiment is configured for installation in an electric vehicle and achieves improved rapid heating performance.

[0022] Figure 1 This is an explanatory diagram showing a general outline of the structure of the vehicle air conditioning unit 1 according to this embodiment. The vehicle air conditioning unit 1 includes a refrigerant circuit 10 configured to circulate refrigerant. The refrigerant is not limited to this; for example, hydrofluoroolefins (HFCs) can be used. In addition, the vehicle air conditioning unit 1 includes a battery temperature regulating circuit 40, for example, configured to circulate a heat carrier fluid such as coolant.

[0023] Additionally, the vehicle air conditioning system 1 includes an HVAC (Heating, Ventilation and Air Conditioning) unit 100 as an air conditioning unit. Furthermore, the vehicle air conditioning system 1 includes a control device 200 (see reference) that controls the operation of various sensors or parts of the vehicle air conditioning system 1. Figure 2 The vehicle air conditioning unit 1 controls its operation based on the detection values ​​of various sensors and various requirements.

[0024] <Refrigerant Circuit>

[0025] The refrigerant circuit 10 includes: a compressor 11 that compresses gaseous refrigerant into high temperature and high pressure and discharges it; a heater core 12 housed in the housing 110 of the HVAC unit 100 and heats the air supplied to the vehicle interior; pressure reducing devices 13a, 13c, 13d, and 13e, such as an expansion valve, that expands liquid refrigerant to low pressure; a low-temperature heat exchanger 14 that absorbs heat by evaporating low-temperature, low-pressure liquid refrigerant; a storage tank 15; a cooler core 16 housed in the housing 110 of the HVAC unit 100 and cools the air supplied to the vehicle interior; and a radiator 17 that serves as an outdoor heat exchanger. The refrigerant circuit 10 is configured to function as a heat pump that circulates and repeatedly compresses, condenses, expands, and evaporates the refrigerant.

[0026] In the low-temperature heat exchanger 14, the refrigerant exchanges heat with a heat carrier circulating in the battery temperature regulation circuit 40. In one illustrated example, the low-temperature heat exchanger 14 includes a refrigerant passage 14a through which the refrigerant circulating in the refrigerant circuit 10 passes and a heat carrier passage 14b through which the heat carrier circulating in the battery temperature regulation circuit 40 passes.

[0027] The various elements of the refrigerant circuit 10 are connected through refrigerant flow paths 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10j, 10k, 10m, 10n, 10p, 10q, 10r, 10s, 10t, 10u, 10v, and 10w.

[0028] The discharge side 11a of the compressor 11 is connected to the inlet side 12a of the heater core 12 via the refrigerant flow path 10a, the bifurcation point 18a and the downstream refrigerant flow path 10b connected thereto.

[0029] The discharge side 11a of compressor 11 is connected to the inlet side 15a of storage tank 15 via refrigerant flow path 10a, branch point 18a, refrigerant flow path 10c, refrigerant flow path 10d, junction point 19a, refrigerant flow path 10e, junction point 19b, and downstream refrigerant flow path 10f. A pressure reducing device 13a, serving as a bypass pressure reducing device, is provided along the path of refrigerant flow path 10c.

[0030] The outlet side 15b of the storage tank 15 is connected to the suction side 11b of the compressor 11 via the refrigerant flow path 10g connected thereto.

[0031] The outlet side 12b of the heater core 12 is connected to the inlet side 16a of the cooler core 16 via a refrigerant flow path 10j, a branch point 18c, a refrigerant flow path 10k, a confluence point 19d, a refrigerant flow path 10m, a branch point 18d, and a downstream refrigerant flow path 10n. A flow path switching valve 20c is provided in the path of the refrigerant flow path 10k. A pressure reducing device 13c is provided in the path of the refrigerant flow path 10n.

[0032] The outlet side 16b of the cooler core 16 is connected to the inlet side 15a of the storage tank 15 via refrigerant flow path 10p, junction point 19e, refrigerant flow path 10q, junction point 19a, refrigerant flow path 10e, junction point 19b, and downstream refrigerant flow path 10f. A backflow prevention valve 21b is provided in the path of refrigerant flow path 10q to prevent refrigerant from flowing back into the cooler core 16.

[0033] The outlet side 12b of the heater core 12 is connected to the inlet of the refrigerant passage 14a of the low-temperature heat exchanger 14 via the refrigerant flow path 10j, the branch point 18c, the refrigerant flow path 10k, the confluence point 19d, the refrigerant flow path 10m, the branch point 18d, and the downstream refrigerant flow path 10r. A pressure reducing device 13d is provided along the path of the refrigerant flow path 10r.

[0034] The outlet of the refrigerant passage 14a of the low-temperature heat exchanger 14 is connected to the inlet side 15a of the storage tank 15 via the refrigerant flow path 10s connected thereto, the junction point 19b and the downstream refrigerant flow path 10f.

[0035] The outlet side 12b of the heater core 12 is connected to the inlet side 17a of the radiator 17 via the refrigerant flow path 10j connected thereto, the bifurcation point 18c, and the downstream refrigerant flow path 10t. A pressure reducing device 13e is provided in the path of the refrigerant flow path 10t.

[0036] The outlet side 17b of the radiator 17 is connected to the inlet side 15a of the storage tank 15 via a refrigerant flow path 10u, a branch point 18e, a refrigerant flow path 10v, a junction point 19e, a refrigerant flow path 10q, a junction point 19a, a refrigerant flow path 10e, a junction point 19b, and a downstream refrigerant flow path 10f. A flow path switching valve 20e is provided along the path of the refrigerant flow path 10v.

[0037] The outlet side 17b of the radiator 17 is connected to the inlet side 16a of the cooler core 16 via a refrigerant flow path 10u, a branch point 18e, a refrigerant flow path 10w, a confluence point 19d, a refrigerant flow path 10m, a branch point 18d, and a downstream refrigerant flow path 10n. A backflow prevention valve 21c is provided in the path of the refrigerant flow path 10w to prevent refrigerant from flowing back into the radiator 17.

[0038] The outlet side 17b of the radiator 17 is connected to the inlet of the refrigerant passage 14a of the low-temperature heat exchanger 14 via the refrigerant flow path 10u, the branch point 18e, the refrigerant flow path 10w, the confluence point 19d, the refrigerant flow path 10m, the branch point 18d and the downstream refrigerant flow path 10r connected thereto.

[0039] <Battery Temperature Regulation Circuit>

[0040] The battery temperature regulation circuit 40, which serves as a temperature regulation circuit for an on-board heating device, includes the heat carrier passage 14b of the aforementioned low-temperature side heat exchanger 14 and a battery 41, which is an example of an on-board heating device. A battery temperature regulation unit for regulating the temperature of the battery 41 is provided in the battery 41. The battery temperature regulation circuit 40 is capable of regulating the temperature of the battery 41.

[0041] In addition, the same structure as the battery temperature regulation circuit 40 can also be applied to other vehicle equipment temperature regulation circuits, which have a vehicle equipment temperature regulation unit for regulating the temperature of other vehicle equipment that also require temperature regulation, not just the battery.

[0042] In one illustrated example, the elements of the battery temperature regulation loop 40 are connected by heat transfer fluid flow paths 40a and 40b. The inlet side 41a of the battery 41 is connected to the outlet of the heat transfer fluid passage 14b of the low-temperature heat exchanger 14 via the heat transfer fluid flow path 40a. The outlet side 41b of the battery 41 is connected to the inlet of the heat transfer fluid passage 14b of the low-temperature heat exchanger 14 via the heat transfer fluid flow path 40b.

[0043] Along the path of the heat transfer fluid flow path 40b, a circulation pump P40 and a heat transfer fluid heating device 42 are sequentially arranged from its upstream side. The heat transfer fluid can be circulated by the circulation pump P40. The heat transfer fluid heating device 42 can heat the heat transfer fluid. The temperature of the battery 41 can be regulated using the heat transfer fluid. Thus, the battery temperature regulation circuit 40, which serves as the temperature regulation circuit for the vehicle-mounted heating device, is a heat transfer fluid circuit for circulating the heat transfer fluid.

[0044] <HVAC Unit>

[0045] The heater core 12 and cooler core 16 of the refrigerant circuit 10 are housed within the housing 110 of the HVAC unit 100. The housing 110 forms the outer shell of the HVAC unit 100 and forms an airflow path 120 inside it.

[0046] Furthermore, the HVAC unit 100 includes an air intake unit 130. The air intake unit 130 closes either the external air intake for introducing outside air or the internal air intake for introducing inside air, thus switching the air introduced into the housing 110 to either outside air (external air intake) or inside air (internal air recirculation). Moreover, the HVAC unit 100 includes a blower 140, which is disposed adjacent to the air intake unit 130 to deliver the air introduced into the housing 110 to the airflow path 120.

[0047] A cooler core 16 is provided on the upstream side of the airflow path 120. Furthermore, a heater core passage and a bypass passage are formed side-by-side on the downstream side of the airflow path 120. A heater core 12 is provided in the heater core passage. Therefore, if air introduced into the housing 110 is guided to the heater core passage, the air is ventilated to the cooler core 16 and then to the heater core 12. On the other hand, if air introduced into the housing 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 air passing through the heater core passage to air passing through the bypass passage is adjusted by the air mixing baffle 150.

[0048] <Control Device>

[0049] Figure 2 This is an explanatory diagram showing a general structural example of the control device 200 of the vehicle air conditioning unit 1 according to this embodiment.

[0050] The control unit 200 controls the operation of various sensors and components of the vehicle air conditioning system 1. The vehicle air conditioning system 1 operates based on sensor readings and various requirements, controlled by the control unit 200. The control unit 200 is an air conditioning ECU (Electronic Control Unit) used to execute various control modes of the vehicle air conditioning system 1. The various control modes executed by the control unit 200 include a hot air heating mode.

[0051] Various sensors input detection information to the control device 200. In hot gas heating mode, detection information from the supply air temperature sensor 210, external gas temperature sensor 220, refrigerant temperature sensor 230, refrigerant pressure sensor 240, and heat carrier temperature sensor 250 is input to the control device 200.

[0052] Based on detection information from various sensors, the control device 200 controls the operation of the flow path switching valve 20, which includes the aforementioned flow path switching valves 20c and 20e, and selects the path in the refrigerant circuit 10 by opening and closing the flow path switching valve 20. In addition, while selecting the path, the control device 200 also controls the operation of the pressure reducing device 13, which includes the compressor 11, the blower 140, the air mixing baffle 150, the circulation pump P40, and the aforementioned pressure reducing devices 13a, 13c, 13d, and 13e, and controls the heat dissipation of the refrigerant.

[0053] [Operation of the vehicle's air conditioning system]

[0054] Referring to the figures, the specific operation of the vehicle air conditioning unit 1 in this embodiment will be explained.

[0055] <Hot Gas Heating Mode>

[0056] Figure 1 The basic state of the vehicle air conditioning unit 1 is shown when the external gas temperature is extremely low. At this time, the vehicle interior is heated by performing hot air heating.

[0057] In hot gas heating mode, control device 200 sets pressure reducing devices 13c and 13e to fully closed and opens flow path switching valve 20c.

[0058] Thus, the refrigerant discharged from the compressor 11 flows through refrigerant flow paths 10a and 10b and passes through the heater core 12. The refrigerant passing through the heater core 12 flows through refrigerant flow paths 10j, 10k, 10m, and 10r and through the refrigerant passage 14a of the low-temperature heat exchanger 14. The refrigerant passing through the refrigerant passage 14a of the low-temperature heat exchanger 14 flows through refrigerant flow paths 10s and 10f and flows into the storage tank 15. The refrigerant flowing into the storage tank 15 flows through refrigerant flow path 10g and flows into the compressor 11. That is, through the refrigerant flow paths 10a, 10b, 10j, 10k, 10m, 10r, 10s, 10f, and 10g, a circulation path is formed for the refrigerant passing through the compressor 11 to circulate through the heater core 12.

[0059] Additionally, the refrigerant discharged from compressor 11 flows through refrigerant flow paths 10a, 10c, 10d, 10e, and 10f and into storage tank 15. The refrigerant flowing into storage tank 15 flows through refrigerant flow path 10g and into compressor 11. That is, through refrigerant flow paths 10a, 10c, 10d, 10e, 10f, and 10g, a bypass path is formed for the refrigerant passing through compressor 11 to bypass heater core 12.

[0060] The control device 200 adjusts the flow rate of the pressure reducing device 13a, causing a portion of the refrigerant discharged from the compressor 11 to flow to the heater core 12, while the remaining refrigerant flows to the bypass path. As a result, the heat from the refrigerant dissipated in the heater core 12 heats the vehicle interior. Furthermore, the refrigerant flowing through the bypass path returns to the suction side 11b of the compressor 11 at a higher temperature than the refrigerant passing through the heater core 12. Therefore, in hot gas heating mode, the temperature of the refrigerant discharged from the compressor 11 can be increased, maintaining the heating capacity.

[0061] Here, since each part of the battery temperature regulation circuit 40 is also exposed to the external gas, when starting up when the external gas temperature is low, the temperature of the heat carrier of the battery temperature regulation circuit 40 is generally also low, and the temperature of the low-temperature side heat exchanger 14 is also low. Therefore, since the refrigerant passes through the refrigerant passage 14a of the low-temperature side heat exchanger 14, the heat of the refrigerant may sometimes be dissipated to the frame of the low-temperature side heat exchanger 14 or the heat carrier of the battery temperature regulation circuit 40. Such dissipation may hinder the necessary pressure rise of the refrigerant. Therefore, in the vehicle air conditioning device 1 of this embodiment, the operation of the refrigerant circuit 10 is adjusted according to the temperature of the heat carrier of the battery temperature regulation circuit 40, etc. For example, in the hot gas heating mode, when the temperature of the heat carrier flowing through the low-temperature side heat exchanger 14 does not meet the specified conditions, the control device 200 restricts the flow of refrigerant into the low-temperature side heat exchanger 14. Several specific examples of the operation of restricting the flow of refrigerant into the low-temperature side heat exchanger 14 are considered and will be described below.

[0062] (first example)

[0063] Figure 3 This is a flowchart illustrating a first example of the specific control processing steps of the control device 200 when activating the hot gas heating mode. (Refer to...) Figure 3 Flowcharts and Figure 1 The circuit diagram will be used to illustrate the first example.

[0064] When the external gas temperature is low, the control device 200 activates the hot gas heating mode. At this time, the control device 200 sets the pressure reducing devices 13c and 13e to be fully closed.

[0065] In step S101, the control device 200 determines whether the temperature of the heat carrier in the battery temperature regulation circuit 40 is higher than the temperature of the refrigerant in the refrigerant circuit 10. The temperatures of the heat carrier and the refrigerant can be obtained, for example, from the inlet temperature of the low-temperature heat exchanger 14. During startup when the external gas temperature is extremely low, the temperature of the heat carrier is low, often lower than the temperature of the refrigerant. When the temperature of the heat carrier is not higher than the temperature of the refrigerant, the process proceeds to step S102.

[0066] In step S102, the control device 200 determines whether the temperature of the heat carrier is higher than a predetermined temperature than the external gas temperature. The predetermined temperature can be appropriately set or changed depending on various conditions. At startup, the temperature of the heat carrier is often the same as the external gas temperature. If the temperature of the heat carrier is not higher than the predetermined temperature than the external gas temperature, the process proceeds to step S103.

[0067] In step S103, the control device 200 closes the flow path switching valve 20c. As a result, the refrigerant does not flow to the heater core 12, and therefore does not flow to the low-temperature side heat exchanger 14. At this time, all the refrigerant passing through the compressor 11 flows through refrigerant flow paths 10a, 10c, 10d, 10e, 10f, and 10g, and through a bypass path that bypasses the heater core 12. Since all the refrigerant flows through the bypass path, the refrigerant pressure rises rapidly. As a result, the start time of hot gas operation is shortened.

[0068] In step S104, the control device 200 determines whether to continue the hot gas heating mode based on various conditions. If the hot gas heating mode continues, the process returns to step S101. That is, it repeatedly determines whether the temperature of the heat carrier is higher than the refrigerant temperature and whether it is higher than the external gas temperature by a specified temperature. If the temperature of the heat carrier is lower than the refrigerant temperature and not higher than the external gas temperature by a specified temperature, the bypass path continues to be used.

[0069] Soon after, due to the operation of on-board heating devices such as battery 41 or the function of the heat carrier heating device 42, the temperature of the heat carrier also rises. In step S102, when it is determined that the temperature of the heat carrier is higher than the external gas temperature by a specified temperature, the process proceeds to step S105.

[0070] In step S105, the control device 200 opens the flow path switching valve 20c. As a result, refrigerant flows through the heater core 12. That is, through refrigerant flow paths 10a, 10b, 10j, 10k, 10m, 10r, 10s, 10f, and 10g, a circulation path is formed for the refrigerant passing through the compressor 11 via the heater core 12 and the low-temperature side heat exchanger 14. The control device 200 adjusts the flow rate 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 to cause the remaining refrigerant to flow to the bypass path.

[0071] At this time, the refrigerant flows through the heater core 12, reaching a state capable of heating the vehicle interior. The control device 200 activates the blower 140, enabling the use of heat from the refrigerant dissipated in the heater core 12 for interior heating. The refrigerant flows through the low-temperature side heat exchanger 14. Since the temperature of the refrigerant is above the temperature of the heat carrier, the heat from the refrigerant is dissipated to the heat carrier side in the low-temperature side heat exchanger 14. However, since the temperature of the heat carrier is higher than the external gas temperature by a predetermined temperature, the degree of heat dissipation is not significant. Furthermore, the refrigerant flowing through the bypass path returns to the suction side 11b of the compressor 11 at a higher temperature than the refrigerant passing through the heater core 12. Thus, in hot gas heating mode, the temperature of the refrigerant discharged from the compressor 11 can be increased, maintaining the heating capacity.

[0072] In step S106, the control device 200 considers the amount of heat dissipation from the refrigerant to the heat carrier and stops the circulation pump P40. By stopping the circulation pump P40, heat dissipation from the refrigerant to the heat carrier can be suppressed. The circulation pump P40 can also be activated if the battery temperature regulation circuit 40 requires circulation of the heat carrier. Furthermore, if there are switchable flow paths in the battery temperature regulation circuit 40, the flow path can be appropriately switched.

[0073] Next, in step S104, the control device 200 determines whether to continue the hot gas heating mode based on various conditions. If the hot gas heating mode continues, the process returns to step S101. That is, it repeatedly determines whether the temperature of the heat carrier is higher than the refrigerant temperature and whether it is higher than the external gas temperature by a specified temperature. If the temperature of the heat carrier is lower than the refrigerant temperature and higher than the external gas temperature by a specified temperature, the process continues to the state of steps S105 and S106.

[0074] Furthermore, for example, if it is necessary to start heating in the vehicle interior as soon as possible, if the predetermined value used in the determination in step S102 is reduced, the process will proceed to steps S105 and S106 earlier. Conversely, for example, if it is desirable to further suppress refrigerant heat dissipation in the low-temperature side heat exchanger 14, if the predetermined value used in the determination in step S102 is increased, the process in step S103 will last longer. Additionally, an example is shown in step S102 where the refrigerant temperature is not considered; however, the refrigerant temperature can also be used for the determination.

[0075] As described above, since the inflow of refrigerant to the low-temperature side heat exchanger 14 is adjusted according to the temperature of the heat carrier, the heat loss of refrigerant to the heat carrier can be suppressed. As a result, the start time of hot gas operation is shortened.

[0076] Soon, through the operation of on-board heating devices such as battery 41 or the function of the heat carrier heating device 42, the temperature of the heat carrier can rise further. In step S101, when it is determined that the temperature of the heat carrier is higher than the temperature of the refrigerant, the process proceeds to step S107.

[0077] In step S107, the control device 200 opens the flow path switching valve 20c in the same manner as in step S105, allowing the refrigerant to flow to the heater core 12 and the low-temperature heat exchanger 14. In step S108, the control device 200 activates the circulation pump P40. Since the temperature of the heat carrier is higher than that of the refrigerant, the refrigerant absorbs heat from the heat carrier. As a result, the start time of hot gas operation is shortened. In addition, since the refrigerant absorbs heat from the heat carrier, the speed of the compressor 11 can be reduced accordingly, thereby reducing noise and power consumption.

[0078] Next, in step S104, the control device 200 determines whether to continue the hot gas heating mode based on various conditions. If the hot gas heating mode is to continue, the process returns to step S101 to continue the hot gas heating mode. If the hot gas heating mode is not to continue, the processing of this hot gas heating mode ends.

[0079] Through the actions described above, the refrigerant pressure rises more rapidly when the hot air operation begins, enabling the target blowing temperature achieved by the HVAC unit 100 to be reached as quickly as possible. In other words, rapid heating is achieved. Furthermore, noise generation and power consumption of the compressor 11 are reduced.

[0080] The above example uses the temperature value of the heat transfer medium for determination, but it is not limited to this. For example, the temperature difference between the temperature of the heat transfer medium on the inlet side and the temperature of the heat transfer medium on the outlet side of the low-temperature heat exchanger 14 can also be used for determination. When the refrigerant flows through the low-temperature heat exchanger 14, as the refrigerant dissipates heat to the heat transfer medium, the temperature of the heat transfer medium on the outlet side of the low-temperature heat exchanger 14 becomes higher than the temperature of the heat transfer medium on the inlet side. The greater the degree of heat dissipation, the greater this temperature difference becomes. Therefore, if the temperature of the heat transfer medium on the outlet side of the low-temperature heat exchanger 14 is higher than the temperature of the heat transfer medium on the inlet side by a predetermined value, the inflow of refrigerant into the low-temperature heat exchanger 14 can be restricted, or the operation of the circulation pump P40 can be stopped.

[0081] In the first example, the operation proceeds in the aforementioned sequence, for instance, when the heat carrier of the battery temperature regulation circuit 40 cools to the same temperature as the external gas. On the other hand, there are also cases where, for example, the battery 41 is charging before startup, or not much time has passed since operation stopped, and the heat carrier has not yet cooled down, resulting in the temperature of the vehicle-mounted heat-generating device, such as the battery 41, being higher than the external gas temperature or the refrigerant temperature. In this case, in the first example, the refrigerant immediately flows through the low-temperature side heat exchanger 14 upon startup, and in some cases, the refrigerant absorbs heat from the heat carrier of the battery temperature regulation circuit 40. As a result, the refrigerant pressure rises faster at the start of hot-air operation, achieving higher rapid warming performance.

[0082] (Second example)

[0083] In the first example described above, when the temperature of the heat carrier in the battery temperature regulation circuit 40 is very low, the refrigerant bypasses the heater core 12 and the low-temperature side heat exchanger 14 using only a bypass path. In the second example, the refrigerant passing through the heater core 12 bypasses the low-temperature side heat exchanger 14 and passes through the cooler core 16. Figure 4 This is a flowchart illustrating a second example of the specific control processing steps of the control device 200 when activating the hot gas heating mode. (Refer to...) Figure 4 Flowcharts and Figure 5 The second example will be illustrated using a circuit diagram. Additionally, explanations of aspects common to the first example are omitted. The above explanations can also be applied to the second example without contradiction.

[0084] When the external gas temperature is low, the control device 200 activates the hot gas heating mode. At this time, the control device 200 sets the pressure reducing device 13e to fully closed and opens the flow path switching valve 20c.

[0085] In step S201, the control device 200 determines whether the temperature of the heat carrier in the battery temperature regulation circuit 40 is higher than the temperature of the refrigerant in the refrigerant circuit 10. If the temperature of the heat carrier is not higher than the temperature of the refrigerant, the process proceeds to step S202.

[0086] In step S202, the control device 200 determines whether the temperature of the heat carrier is higher than the external gas temperature by a predetermined temperature. If the temperature of the heat carrier is not higher than the external gas temperature by a predetermined temperature, the process proceeds to step S203.

[0087] In step S203, control device 200 closes pressure reducing device 13d and opens pressure reducing device 13c. The result is as follows: Figure 5 As shown, the refrigerant does not flow to the low-temperature side heat exchanger 14, but instead flows to the cooler core 16. That is, through the refrigerant flow paths 10a, 10b, 10j, 10k, 10m, 10n, 10p, 10q, 10e, 10f, and 10g, a circulation path is formed for the refrigerant passing through the compressor 11, via the heater core 12 and the cooler core 16. The control device 200 adjusts the flow rate 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 cooler core 16, while causing the remaining refrigerant to flow to the bypass path.

[0088] In step S204, the control device 200 stops the blower 140. This is because blowing air into the cooler core 16 and the heater core 12 while the refrigerant is flowing through both the heater core 12 upstream of the pressure reducing device 13c and the cooler core 16 downstream is not suitable for the operation of the refrigerant circuit 10.

[0089] In this way, the refrigerant will not flow through the low-temperature side heat exchanger 14, whose temperature has dropped to the outside gas temperature. Therefore, the refrigerant will not dissipate heat to the frame or heat carrier of the low-temperature side heat exchanger 14. For example, in cases such as restarting operation after a relatively short period of shutdown, the temperature inside the vehicle with the cooler core 16 may be higher than that in the motor compartment with the low-temperature side heat exchanger 14. In this case, as shown in this example, the effect of directing the refrigerant to the cooler core 16 is significant. According to this example, by bypassing the low-temperature side heat exchanger 14, the refrigerant pressure can easily rise, and the start time of hot air operation may be faster. In addition, if the temperature inside the vehicle with the cooler core 16 is cooled to the same extent as that in the motor compartment with the low-temperature side heat exchanger 14, the refrigerant flowing through the cooler core 16 may dissipate heat to the same extent as when flowing through the low-temperature side heat exchanger 14. However, the heat dissipated from the cooler core 16 preheats the HVAC unit 100. This operation can be referred to as the preparation for operation of the HVAC unit 100. In this case, as will be described later, the pressure drop of the refrigerant that may occur as heat is dissipated from the heater core 12 when the blower 140 is started can be suppressed, and the start time of hot gas operation can be accelerated. That is, heat is utilized effectively as a whole.

[0090] In step S205, the control device 200 determines whether to continue the hot gas heating mode based on various conditions. If the hot gas heating mode continues, the process returns to step S201. That is, it repeatedly determines whether the temperature of the heat carrier is higher than the refrigerant temperature and whether it is higher than the external gas temperature by a specified temperature. If the temperature of the heat carrier is lower than the refrigerant temperature and not higher than the external gas temperature by a specified temperature, the flow path through the cooler core 16 continues to be used.

[0091] In step S202, if it is determined that the temperature of the heat carrier is higher than the external gas 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. The result is as follows: Figure 1 As shown, the refrigerant does not flow to the cooler core 16, but instead flows to the low-temperature side heat exchanger 14. That is, through the refrigerant flow paths 10a, 10b, 10j, 10k, 10m, 10r, 10s, 10f, and 10g, a circulation path is formed for the refrigerant passing through the compressor 11, via the heater core 12 and the low-temperature side heat exchanger 14. The control device 200 adjusts the flow rate 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 to cause the remaining refrigerant to flow to the bypass path.

[0092] In step S207, the control device 200 activates the blower 140, enabling indoor heating to be utilized using the heat dissipated by the refrigerant in the heater core 12. As described above, the heat dissipated by the refrigerant as it flows through the cooler core 16 can also be utilized during the operation of the air conditioner.

[0093] The refrigerant flows through the low-temperature side heat exchanger 14. Since the temperature of the refrigerant is above the temperature of the heat carrier, the refrigerant dissipates heat to the heat carrier side in the low-temperature side heat exchanger 14. However, since the temperature of the heat carrier is higher than the external gas temperature by a predetermined temperature, the degree of heat dissipation is not significant. On the other hand, the refrigerant flowing through the bypass path returns to the suction side 11b of the compressor 11 at a higher temperature than the refrigerant passing through the heater core 12. Therefore, in the hot gas heating mode, the temperature of the refrigerant discharged from the compressor 11 can be increased and the heating capacity can be maintained.

[0094] In step S208, the control device 200 considers the amount of heat dissipation from the refrigerant to the heat carrier and stops the circulation pump P40. By stopping the circulation pump P40, heat dissipation from the refrigerant to the heat carrier can be suppressed.

[0095] Next, in step S205, the control device 200 determines whether to continue the hot gas heating mode based on various conditions. If the hot gas heating mode is to continue, the process returns to step S201. If the temperature of the heat carrier is below the refrigerant temperature and exceeds the specified temperature of the external gas, the process continues to the state of steps S206 to S208.

[0096] Since the flow of refrigerant into the low-temperature side heat exchanger 14 is adjusted according to the temperature of the heat carrier, the heat loss of refrigerant to the heat carrier can be suppressed, resulting in a shorter start time for hot gas operation.

[0097] In step S201, if it is determined that the temperature of the heat carrier is higher than the temperature of the refrigerant, the process proceeds to step S209. In step S209, the control device 200 directs the refrigerant to flow to the heater core 12 and the low-temperature side heat exchanger 14. In step S210, the control device 200 activates the circulation pump P40. Since the temperature of the heat carrier is higher than the temperature of the refrigerant, the refrigerant absorbs heat from the heat carrier. As a result, the start time of hot gas operation is shortened. In addition, since the refrigerant absorbs heat from the heat carrier, the speed of the compressor 11 can be reduced accordingly, thereby reducing noise and power consumption.

[0098] Next, in step S205, the control device 200 determines whether to continue the hot gas heating mode based on various conditions. If the hot gas heating mode is to continue, the process returns to step S201 to continue the hot gas heating mode. If the hot gas heating mode is not to continue, the processing of this hot gas heating mode ends.

[0099] Through the actions described above, the refrigerant pressure rises more rapidly during the start-up of the hot air system, enabling the target blowing temperature of the HVAC unit 100 to be achieved as quickly as possible. In other words, rapid heating is achieved. Furthermore, noise generation and power consumption of the compressor 11 are reduced.

[0100] (Third case)

[0101] In the second example described above, when the temperature of the heat carrier in the battery temperature regulation circuit 40 is very low, the refrigerant passing through the heater core 12 bypasses the low-temperature side heat exchanger 14 and passes through the cooler core 16. In the third example, as... Figure 6 As shown, a refrigerant flow path 10x is provided in the refrigerant circuit 10 that bypasses the low-temperature side heat exchanger 14.

[0102] More specifically, a three-way valve V31 is provided in the refrigerant flow path 10r, which is the refrigerant passage 14a leading from the pressure reducing device 13d to the low-temperature heat exchanger 14. One side of the three-way valve V31 connected to the refrigerant flow path 10r connects the refrigerant flow path 10r to the refrigerant flow path 10y, which is equipped with the low-temperature heat exchanger 14. The other side of the three-way valve V31 connected to the refrigerant flow path 10r connects the refrigerant flow path 10r to the refrigerant flow path 10x, which serves as a bypass path for the low-temperature heat exchanger, bypassing the junction point 19f of the refrigerant flow path 10s connected to the storage tank 15 and the low-temperature heat exchanger 14. A backflow prevention valve 21d is provided on the path of the refrigerant flow path 10y, which connects the low-temperature heat exchanger 14 to the junction point 19f, to prevent refrigerant from flowing back into the low-temperature heat exchanger 14.

[0103] Figure 7 This is a flowchart illustrating a third example of the specific control processing steps of the control device 200 when activating the hot gas heating mode. (Refer to...) Figure 7 Flowcharts and Figure 6 The third example will be illustrated using a circuit diagram. Additionally, explanations of aspects common to the first example are omitted. The above explanations can also be applied to the third example without contradiction.

[0104] When the external gas temperature is low, the control device 200 activates the hot gas heating mode. At this time, the control device 200 sets the pressure reducing devices 13c and 13e to be fully closed and opens the flow path switching valve 20c.

[0105] In step S301, the control device 200 determines whether the temperature of the heat carrier in the battery temperature regulation circuit 40 is higher than the temperature of the refrigerant in the refrigerant circuit 10. If the temperature of the heat carrier is not higher than the temperature of the refrigerant, the process proceeds to step S302.

[0106] In step S302, the control device 200 switches the three-way valve V31 so that the refrigerant does not flow to the low-temperature side heat exchanger 14 but flows to the refrigerant flow path 10x that bypasses the low-temperature side heat exchanger 14. As a result, as... Figure 6 As shown, refrigerant flows through refrigerant paths 10a, 10b, 10j, 10k, 10m, 10r, 10x, 10s, 10f, and 10g, forming a circulation path for the refrigerant passing through compressor 11, via heater core 12, and bypassing low-temperature heat exchanger 14. Control device 200 adjusts the flow rate of pressure reducing device 13a to direct a portion of the refrigerant discharged from compressor 11 to heater core 12, and directs the remaining refrigerant to the bypass path.

[0107] Because the refrigerant does not flow to the low-temperature side heat exchanger 14, where the temperature drops to the outside gas temperature, the refrigerant does not dissipate heat to the frame or heat carrier of the low-temperature side heat exchanger 14. As a result, the refrigerant pressure tends to rise, and the start-up time of hot gas operation may be faster.

[0108] In step S303, the control device 200 determines whether to continue the hot gas heating mode based on various conditions. If the hot gas heating mode continues, the process returns to step S301. That is, it repeatedly determines whether the temperature of the heat carrier is higher than the refrigerant temperature. When the temperature of the heat carrier is lower than the refrigerant temperature, the refrigerant continues to bypass the low-temperature side heat exchanger 14.

[0109] In step S301, if it is determined that the temperature of the heat carrier 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 to direct the refrigerant flow to the low-temperature side heat exchanger 14. As a result, a circulation path is formed through the refrigerant flow paths 10a, 10b, 10j, 10k, 10m, 10r, 10y, 10s, 10f, and 10g for the refrigerant passing through the compressor 11, via the heater core 12 and the low-temperature side heat exchanger 14. The control device 200 adjusts the throttling of the pressure reducing device 13a to direct a portion of the refrigerant discharged from the compressor 11 to the heater core 12 and direct the remaining refrigerant to the bypass path.

[0110] In step S305, control device 200 activates circulation pump P40. Since the temperature of the heat carrier is higher than the temperature of the refrigerant, the refrigerant absorbs heat from the heat carrier. As a result, the start time of hot gas operation is shortened.

[0111] Next, in step S303, the control device 200 determines whether to continue the hot gas heating mode based on various conditions. If the hot gas heating mode is to continue, the process returns to step S301 to continue the hot gas heating mode. If the hot gas heating mode is not to continue, the processing of this hot gas heating mode ends.

[0112] Through the actions described above, the refrigerant pressure rises more rapidly during the start-up of the hot air system, enabling the target blowing temperature of the HVAC unit 100 to be achieved as quickly as possible. In other words, rapid heating is achieved. Furthermore, noise generation and power consumption of the compressor 11 are reduced.

[0113] Furthermore, the actions described in the first to third examples can be appropriately combined. That is, based on conditions such as the temperature of the heat carrier in the battery temperature regulation circuit 40, the pressure and temperature of the refrigerant, the control device 200 may, for example, cause the refrigerant to bypass the heater core 12, or flow to the heater core 12 and the cooler core 16, or flow into the heater core 12 while simultaneously bypassing the low-temperature side heat exchanger 14, or flow into the heater core 12 and the low-temperature side heat exchanger 14. Additionally, the control device 200 may circulate or not circulate the heat carrier in the battery temperature regulation circuit 40. By appropriately combining these actions, the control device 200 can accelerate the start of hot air circulation and achieve rapid heating.

[0114] [Regarding automotive air conditioning systems]

[0115] The vehicle air conditioning unit 1 of this embodiment can achieve the following effects.

[0116] (a1) The vehicle air conditioning unit 1 includes a refrigerant circuit, which includes: a compressor 11; a heater core 12 configured to heat the air supplied to the vehicle interior; a pressure reducing device 13; and a low-temperature heat exchanger 14 configured to exchange heat between a heat carrier that exchanges heat with the vehicle heating equipment and the refrigerant, and has: a path configured to circulate the refrigerant in the compressor 11, the heater core 12, the pressure reducing device 13, and the low-temperature heat exchanger 14; and a bypass path for the refrigerant passing through the compressor 11 to bypass the heater core 12 and flow into the suction side of the compressor. The vehicle air conditioning unit 1 also includes: a heat carrier circuit, such as a battery temperature regulation circuit 40, configured to circulate the heat carrier within an on-board heating device, such as a battery 41, and a low-temperature side heat exchanger 14; and a control device 200 configured to switch and control the refrigerant circuit 10, enabling a portion of the refrigerant passing through the compressor 11 to flow to the heater core 12, and the remaining refrigerant to flow to a bypass path in hot gas heating mode. In hot gas heating mode, the control device 200 restricts the inflow of refrigerant into the low-temperature side heat exchanger 14 when the temperature of the heat carrier flowing through the low-temperature side heat exchanger 14 does not meet specified conditions.

[0117] Therefore, the vehicle air conditioning unit 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 carrier flowing through the low-temperature side heat exchanger 14, the refrigerant dissipates heat to the heat carrier. In this case, the temperature of the refrigerant on the suction side of the compressor 11 decreases, and the refrigerant is difficult to reach an appropriate state, thus lengthening the time until the target heating capacity is reached. In contrast, the vehicle air conditioning unit 1 of this embodiment, for example, restricts the flow of refrigerant into the low-temperature side heat exchanger 14 before the temperature of the heat carrier flowing through the low-temperature side heat exchanger 14 exceeds the temperature of the refrigerant flowing through the low-temperature side heat exchanger 14. This prevents the refrigerant from dissipating heat to the heat carrier, suppresses the 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 rapid heating performance can be improved.

[0118] (a2) For example, when the hot gas heating mode is started, the control device 200 restricts the flow of refrigerant into the low-temperature side heat exchanger 14 before the temperature of the heat carrier flowing through the low-temperature side heat exchanger 14 exceeds a predetermined reference temperature.

[0119] Therefore, the vehicle air conditioning unit 1 of this embodiment can shorten the time required to reach the target heating capacity when the hot air heating mode is activated. At startup, it is assumed that the overall system temperature is close to the outside air temperature. The vehicle air conditioning unit 1 of this embodiment also has a special effect during startup. The aforementioned reference temperature can be a specified temperature, the temperature of the refrigerant flowing through the low-temperature side heat exchanger 14, or a value higher than the outside air temperature by a specified temperature.

[0120] (a3) The heat carrier circuit such as the battery temperature regulation circuit 40 may also include a heat carrier heating device 42 configured to heat the heat carrier.

[0121] By using the heat carrier heating device 42 to heat the heat carrier, the temperature of the heat carrier can rise in a shorter time. This shortens the time until the temperature of the heat carrier meets the specified conditions. Furthermore, it further suppresses heat loss from the refrigerant to the heat carrier. As a result, the time to reach the target heating capacity is shortened, and rapid heating performance is improved.

[0122] (a4) The heat carrier circuit also includes a circulation pump P40 configured to circulate the heat carrier, and the control device 200 may also be configured to control the operation or stop of the circulation pump P40 based on the temperature of the heat carrier in the hot gas heating mode.

[0123] When the temperature of the heat transfer medium is lower than the temperature of the refrigerant, the refrigerant can dissipate heat to the heat transfer medium in the low-temperature side heat exchanger 14. In this case, stopping the circulation of the heat transfer medium by stopping the circulation pump P40 can suppress this heat dissipation. When the temperature of the heat transfer medium is higher than the temperature of the refrigerant, the refrigerant can absorb heat from the heat transfer medium in the low-temperature side heat exchanger 14. In this case, circulating the heat transfer medium by operating the circulation pump P40 can improve the efficiency of this heat absorption. All of the above contribute to shortening the time to reach the target heating capacity and improving rapid heating performance.

[0124] (a5) When the temperature of the heat carrier flowing through the low-temperature heat exchanger 14 does not meet the specified conditions, such as when the temperature of the heat carrier flowing through the low-temperature heat exchanger 14 does not exceed the specified reference temperature, when the temperature of the heat carrier flowing through the low-temperature heat exchanger 14 is not higher than the specified temperature of the outside gas, when the temperature difference between the temperature of the heat carrier at the outlet side and the temperature of the heat carrier at the inlet side of the low-temperature heat exchanger 14 exceeds the specified value, or when the temperature of the heat carrier flowing through the low-temperature heat exchanger 14 does not exceed the temperature of the refrigerant flowing through the low-temperature heat exchanger 14, etc.

[0125] The specified reference temperature can be set, for example, as a lower temperature that delays the achievement of the target heating capacity. By restricting the inflow of refrigerant into the low-temperature side heat exchanger 14 when the temperature of the heat carrier flowing through it does not exceed the specified reference temperature, heat loss can be suppressed, preventing delays in achieving the target heating capacity. Additionally, a temperature higher than a specified temperature than the outside gas temperature can be set, for example, as a lower temperature that delays the achievement of the target heating capacity. By restricting the inflow of refrigerant into the low-temperature side heat exchanger 14 when the temperature of the heat carrier flowing through it does not exceed a specified temperature above the outside gas temperature, heat loss can be suppressed, preventing delays in achieving the target heating capacity. When the temperature difference between the heat carrier at the outlet side and the heat carrier at the inlet side of the low-temperature side heat exchanger 14 exceeds a specified value, significant heat dissipation occurs from the refrigerant to the heat carrier. By restricting the inflow of refrigerant into the low-temperature heat exchanger 14 when the temperature difference between the heat carrier at the outlet side and the heat carrier at the inlet side exceeds a predetermined value, heat loss can be suppressed, preventing delays in achieving the target heating capacity. When the temperature of the heat carrier flowing through the low-temperature heat exchanger 14 does not exceed the temperature of the refrigerant flowing through the low-temperature heat exchanger 14, heat dissipation from the refrigerant to the heat carrier can occur. By restricting the inflow of refrigerant into the low-temperature heat exchanger 14 when the temperature of the heat carrier flowing through the low-temperature heat exchanger 14 does not exceed the temperature of the refrigerant flowing through the low-temperature heat exchanger 14, heat loss can be suppressed, delays in achieving the target heating capacity can be prevented, and rapid heating performance can be improved.

[0126] (a6) Control device 200, for example, when the temperature of the heat carrier flowing through the low-temperature side heat exchanger 14 does not meet the specified conditions, directs all the refrigerant flowing through the compressor 11 to the bypass path.

[0127] This suppresses heat dissipation of the refrigerant in the heater core 12 and also suppresses heat dissipation of the refrigerant in the low-temperature side heat exchanger 14. As a result, the time to reach the target heating capacity is shortened, and rapid heating performance is improved.

[0128] (a7) The refrigerant circuit 10 includes a cooler core 16, which is disposed downstream of the pressure reducing device 13c and configured to exchange heat with the air supplied to the vehicle interior. The control device 200 may also cause at least a portion of the refrigerant passing through the compressor 11 to flow to the heater core 12, the pressure reducing device 13c and the cooler core 16 when the temperature of the heat carrier flowing through the low-temperature side heat exchanger 14 does not meet the specified conditions.

[0129] Therefore, the refrigerant dissipates heat not in the low-temperature heat exchanger 14, but in the cooler core 16, preheating the air inside the HVAC unit 100. As a result, the load on the heater core 12 at the start of air supply from the subsequent blower 140 can be suppressed, and the reduction in refrigerant pressure at the outlet side of the heater core 12 that may occur at the start of air supply can be suppressed. Consequently, the time to reach the target heating capacity can be shortened, and rapid heating performance can be improved.

[0130] (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. The control device 200 can also direct at least a portion of the refrigerant passing through the compressor 11 to the heater core 12, the pressure reducing device 13d and the low-temperature side heat exchanger bypass flow path when the temperature of the heat carrier flowing through the low-temperature side heat exchanger 14 does not meet the specified conditions.

[0131] This suppresses heat loss from the refrigerant in the low-temperature side heat exchanger 14. As a result, the time required to reach the target heating capacity is shortened, and rapid heating is improved.

[0132] (b1) The vehicle air conditioning unit 1 includes a refrigerant circuit, which includes: a compressor 11; a heater core 12 configured to heat air supplied to the vehicle interior; a pressure reducing device 13; a cooler core 16 configured to cool air supplied to the vehicle interior; and a low-temperature side heat exchanger 14 configured to exchange heat with the refrigerant, and has: a path configured to circulate the refrigerant in 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 in the compressor 11, the heater core 12, the pressure reducing device 13c and the cooler core 16; and a bypass path for the refrigerant passing through the compressor 11 to bypass the heater core 12 and flow into the suction side of the compressor 11. The vehicle air conditioning unit 1 further includes: an HVAC unit 100 as an air conditioning unit, the HVAC unit 100 having a heater core 12, a cooler core 16, and a blower 140 for supplying air to 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, enabling control in a hot gas heating mode where a portion of the refrigerant passing through the compressor 11 flows to the heater core 12, and the remaining refrigerant flows to a bypass path. In hot gas heating mode, the control device 200 can achieve control in a standby state where the refrigerant circulates in the compressor 11, heater core 12, pressure reducing device 13c, and cooler core 16, and prohibits air supply by the blower 140.

[0133] Therefore, the vehicle air conditioning unit 1 of this embodiment can shorten the time until the target heating capacity is reached. For example, when the temperature of the heat carrier flowing through the low-temperature side heat exchanger 14 is low, the refrigerant dissipates heat to the heat carrier. In this case, the temperature of the refrigerant on the suction side of the compressor 11 decreases, and the refrigerant is difficult to reach a suitable state, thus lengthening the time until the target heating capacity is reached. In contrast, the vehicle air conditioning unit 1 of this embodiment, for example, suppresses the inflow of refrigerant into the low-temperature side heat exchanger 14 before the temperature of the heat carrier flowing through the low-temperature side heat exchanger 14 rises to a certain level, thereby preventing heat dissipation from the refrigerant to the heat carrier. As a result, the temperature drop of the refrigerant can be suppressed, the temperature rise of the refrigerant can be improved, the time until the target heating capacity is reached can be shortened, and the rapid 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, preheating the air inside the HVAC unit 100. As a result, the load on the heater core 12 at the start of air supply from the blower 140 can be suppressed, and the reduction in refrigerant pressure at the outlet side of the heater core 12 that may occur at the start of air supply can be suppressed. This also improves the refrigerant temperature rise, shortens the time to reach the target heating capacity, and enhances rapid heating performance. The blower 140 is stopped while the refrigerant flows through the heater core 12 and the cooler core 16 to prevent abnormalities in the refrigerant circuit 10 circulation.

[0134] (b2) Control device 200, for example in hot gas heating mode, after preparation for operation, can realize the control of air conditioning operation under which the refrigerant circulates in compressor 11, heater core 12, pressure reducing device 13d and low temperature side heat exchanger 14, and then allows air supply by blower 140.

[0135] By changing the refrigerant flow path from the cooler core 16 to the low-temperature heat exchanger 14 before starting the blower 140, the decrease in the temperature of the refrigerant on the suction side of the compressor 11 can be suppressed. This prevents the hot gas circulation from shrinking.

[0136] (c1) The vehicle air conditioning unit 1 includes a refrigerant circuit, which includes: a compressor 11; a heater core 12 configured to heat air supplied to the vehicle interior; a pressure reducing device 13; 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 bypassing the low-temperature side heat exchanger 14, and has: a path configured to circulate the refrigerant in the compressor 11, heater core 12, pressure reducing device 13d and low-temperature side heat exchanger 14; a path configured to circulate the refrigerant in the compressor 11, heater core 12, pressure reducing device 13d and low-temperature side heat exchanger bypass flow path; and a bypass path through which the refrigerant passing through the compressor 11 bypasses the heater core 12 and flows into the suction side of the compressor 11. The vehicle air conditioning unit 1 also includes a control device configured to switch and control the refrigerant circuit 10, enabling control in a hot gas heating mode where a portion of the refrigerant passing through the compressor 11 flows to the heater core 12 and the remaining refrigerant flows to the bypass path. In hot gas heating mode, the control device 200 can control the refrigerant to circulate in the bypass path of the compressor 11, heater core 12, pressure reducing device 13d, and low-temperature heat exchanger, bypassing the low-temperature heat exchanger 14.

[0137] Therefore, the vehicle air conditioning unit 1 of this embodiment can shorten the time until the target heating capacity is reached. For example, when the temperature of the heat carrier flowing through the low-temperature side heat exchanger 14 is low, the refrigerant dissipates heat to the heat carrier. In this case, the temperature of the refrigerant on the suction side of the compressor 11 decreases, making it difficult for the refrigerant to reach an appropriate state, and the time until the target heating capacity is reached becomes longer. In contrast, the vehicle air conditioning unit 1 of this embodiment, for example, prevents the refrigerant from dissipating heat to the heat carrier by suppressing the inflow of refrigerant into the low-temperature side heat exchanger 14 before the temperature of the heat carrier flowing through the low-temperature side heat exchanger 14 rises to a certain level. As a result, the temperature drop of the refrigerant can be suppressed, the temperature rise of the refrigerant can be improved, the time until the target heating capacity is reached can be shortened, and the rapid heating performance can be improved.

[0138] (c2) The refrigerant circuit 10 may also include a backflow prevention valve 21d, which is configured to prevent refrigerant flowing through the low-temperature side heat exchanger bypass path from flowing back into the low-temperature side heat exchanger 14.

[0139] Therefore, it is possible to suppress the decrease in refrigerant pressure on the suction side of compressor 11 caused by refrigerant backflow into low-temperature heat exchanger 14.

[0140] (c3) The low-temperature side heat exchanger 14 is configured to allow the heat carrier that exchanges heat with the vehicle-mounted heat-generating device such as the battery 41 to exchange heat with the refrigerant. The control device 200 can also, in the hot gas heating mode, allow the refrigerant to circulate in the compressor 11, heater core 12, pressure reducing device 13d and low-temperature side heat exchanger bypass flow path to bypass the low-temperature side heat exchanger 14 when the temperature of the heat carrier flowing through the low-temperature side heat exchanger 14 does not exceed the temperature of the refrigerant.

[0141] Therefore, heat dissipation of the refrigerant in the low-temperature side heat exchanger 14 can be suppressed. That is, when the temperature of the heat carrier flowing through the low-temperature side heat exchanger 14 is lower than the temperature of the refrigerant flowing through the low-temperature side heat exchanger 14, the refrigerant dissipates heat to the heat carrier. By allowing the refrigerant to bypass the low-temperature side heat exchanger 14 and flow into the low-temperature side heat exchanger bypass path, such heat dissipation of the refrigerant can be suppressed. As a result, the time to reach the target heating capacity can be shortened, and the rapid heating performance can be improved.

[0142] The preferred embodiments have been shown above and the present invention has been described. However, the present invention is not limited to the foregoing embodiments, and various changes can be made within the scope of the present invention, which goes without saying.

[0143] Symbol Explanation

[0144] 1: Vehicle air conditioning unit; 10: Refrigerant circuit; 11: Compressor; 12: Heater core; 13, 13a, 13c, 13d, 13e: Pressure reducing device; 14: Low-temperature side heat exchanger; 15: Storage tank; 16: Cooler core; 17: Radiator; 20, 20c, 20e: Flow path switching valve; 40: Battery temperature regulation circuit; 41: Battery; 42: Heat carrier heating device; P40: Circulation pump; 100: HVAC unit, 110: housing, 120: airflow path, 140: blower, 150: air mixing baffle.

Claims

1. A vehicle air conditioning unit, comprising: A refrigerant circuit includes: a compressor; a heater core configured to heat air supplied to the vehicle interior; a pressure reducing device; and a low-temperature heat exchanger configured to exchange heat between a heat carrier that exchanges heat with on-board heating equipment and the refrigerant, and has: a path configured to circulate the refrigerant in the compressor, the heater core, the pressure reducing device, and the low-temperature heat exchanger; and a bypass path through which the refrigerant bypasses the heater core and flows into the suction side of the compressor. A heat carrier circuit, the heat carrier circuit being configured to circulate the heat carrier between the on-board heating device and the low-temperature side heat exchanger; and The control device is configured to switch and control the refrigerant circuit, enabling control in a hot gas heating mode to direct a portion of the refrigerant passing through the compressor to the heater core and the remaining refrigerant to the bypass path. In the hot gas heating mode, when the temperature of the heat carrier flowing through the low-temperature side heat exchanger does not meet the specified conditions, the control device restricts the flow of refrigerant into the low-temperature side heat exchanger.

2. The vehicle air conditioning device as described in claim 1, characterized in that, When the hot gas heating mode is activated, the control device restricts the flow of refrigerant into the low-temperature side heat exchanger before the temperature of the heat carrier flowing through the low-temperature side heat exchanger exceeds a predetermined reference temperature.

3. The vehicle air conditioning device as described in claim 1 or 2, characterized in that, The heat carrier circuit also includes a heat carrier heating device configured to heat the heat carrier.

4. The vehicle air conditioning device as described in claim 1 or 2, characterized in that, The heat carrier circuit also includes a circulation pump configured to circulate the heat carrier. The control device is configured to control the operation or stop of the circulating pump based on the temperature of the heat carrier in the hot gas heating mode.

5. The vehicle air conditioning device as described in claim 1, characterized in that, When the temperature of the heat carrier flowing through the low-temperature side heat exchanger does not meet the specified conditions, the control device restricts the inflow of the refrigerant into the low-temperature side heat exchanger. When the temperature of the heat carrier flowing through the low-temperature side heat exchanger does not exceed the specified reference temperature, When the temperature of the heat carrier flowing through the low-temperature side heat exchanger is not higher than the external gas temperature by a specified temperature, When the temperature difference between the heat transfer fluid at the outlet side and the heat transfer fluid at the inlet side of the low-temperature heat exchanger exceeds a predetermined value, or When the temperature of the heat carrier flowing through the low-temperature side heat exchanger does not exceed the temperature of the refrigerant flowing through the low-temperature side heat exchanger.

6. The vehicle air conditioning device as described in claim 1 or 2, characterized in that, When the temperature of the heat carrier flowing through the low-temperature side heat exchanger does not meet the specified conditions, the control device directs all the refrigerant passing through the compressor to the bypass path.

7. The vehicle air conditioning device as described in claim 1 or 2, characterized in that, The refrigerant circuit includes a cooler core disposed downstream of the pressure reducing device and configured to exchange heat with the air supplied to the vehicle interior. When the temperature of the heat carrier flowing through the low-temperature side heat exchanger does not meet the specified conditions, the control device directs at least a portion of the refrigerant passing through the compressor to the heater core, the pressure reducing device, and the cooler core.

8. The vehicle air conditioning unit as described in claim 1 or 2, characterized in that, The refrigerant circuit has a low-temperature side heat exchanger bypass path that bypasses the low-temperature side heat exchanger. When the temperature of the heat carrier flowing through the low-temperature heat exchanger does not meet the specified conditions, the control device directs at least a portion of the refrigerant passing through the compressor to the heater core, the pressure reducing device, and the bypass path of the low-temperature heat exchanger.

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