Vehicle air conditioning device

Abstract

Shortening the time for the high-pressure side refrigerant pressure of a refrigerant circuit to reach a target pressure and ensuring rapid heating. Provided is a vehicle air-conditioning device including: a refrigerant circuit having a compressor, an indoor heat exchange portion, an external heat exchange portion, and a hot gas bypass that depressurizes at least a portion of refrigerant compressed in the compressor without passing through the indoor heat exchange portion and the external heat exchange portion and returns the portion to the compressor; an air conditioning unit that configures the indoor heat exchange portion inside, has a blower that blows air inside, and has an air damper that adjusts the proportion of air blown by the blower to the indoor heat exchange portion; and a control device that controls the refrigerant circuit and the air conditioning unit, the control device controlling the air damper so that at least a portion of the air bypasses the indoor heat exchange portion when starting to execute a hot gas heating mode and starting the blower, the hot gas heating mode causing a portion of the refrigerant compressed in the compressor to flow through the indoor heat exchange portion and causing the remaining portion to flow through the hot gas bypass.

Description

Technical Field

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

[0002] In recent years, hybrid vehicles and electric vehicles, which use electricity supplied from a battery installed in the vehicle to drive an electric motor, have become increasingly popular. As an air conditioning system installed in such vehicles, a device that uses a heat pump (refrigerant circuit) as a heat source is known.

[0003] In automotive air conditioning systems using heat pumps, the external heat exchanger functions as a heat absorber during heating operation, drawing heat from the external atmosphere. Therefore, when the external atmosphere temperature is extremely low, it becomes difficult to absorb heat from it, significantly reducing heating capacity. In contrast, for effective heating in extremely low-temperature environments, a method is known that utilizes the hot gas from the high-temperature, high-pressure refrigerant discharged from the compressor, rather than absorbing heat from external gases.

[0004] For example, in the automotive air conditioning system of Patent Document 1, the refrigerant is circulated in the heat pump to perform hot air heating operation in the following manner: In the heat pump, a portion of the high-temperature, high-pressure refrigerant discharged from the compressor is returned to the compressor after flowing through a bypass path and being depressurized, while the remaining portion is depressurized after exchanging heat with the air supplied to the vehicle interior in the indoor heat exchanger, and then returned to the compressor without passing through an external heat exchanger.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2023-46604 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] In the automotive air conditioning system described above, when the hot air heating operation is started, in order to ensure rapid heating, the blower is stopped and the heat dissipation in the indoor heat exchanger is limited. At the same time, the compressor is driven at a higher target speed so that the outlet refrigerant pressure Pci of the indoor heat exchanger reaches the target outlet refrigerant pressure PCO as quickly as possible.

[0010] On the other hand, if the compressor continues to run under such conditions, the outlet refrigerant pressure Pci will rise sharply and overshoot, potentially causing the compressor to stop due to high-pressure protection. Conversely, if the compressor's target speed is reduced, it will take time for the outlet refrigerant pressure Pci to reach the target outlet refrigerant pressure PCO.

[0011] Therefore, in automotive air conditioning systems, the blower is driven when the outlet refrigerant pressure Pci rises to a certain level. By releasing the heat of the refrigerant to the air supplied to the indoor heat exchanger, a rapid and excessive rise in the outlet refrigerant pressure Pci can be suppressed. At this time, in order to prevent excessive heat dissipation in the indoor heat exchanger, the blower is driven at its minimum speed (lowest voltage) at least at the start of its operation, thus achieving the minimum airflow.

[0012] However, the minimum rotational speed of the blower is determined by specifications, and it cannot be driven in a way that produces a smaller airflow than the minimum airflow obtained by driving it at the minimum speed. Therefore, air is supplied to the indoor heat exchanger at the minimum airflow determined by specifications, which sometimes causes a temporary and significant drop in the outlet refrigerant pressure Pci. In this situation, time is required before the target outlet refrigerant pressure PCO is reached, defeating the purpose of ensuring rapid heating.

[0013] The present invention was made in view of the following situation, and its technical problem is to shorten the time for the refrigerant pressure on the high-pressure side of the refrigerant circuit to reach the target pressure, shorten the time for reaching the target blowing temperature and the target heating capacity, and thus ensure rapid heating performance during hot gas heating operation.

[0014] Technical solutions adopted to solve technical problems

[0015] This invention provides an automotive air conditioning device, comprising: a refrigerant circuit having a compressor, an indoor heat exchange section, an external heat exchange section, and a hot gas bypass, wherein the hot gas bypass causes at least a portion of the refrigerant compressed in the compressor to be depressurized and returned to the compressor without passing through the indoor and external heat exchange sections; an air conditioning unit having the indoor heat exchange section disposed internally and having a blower for supplying air to the interior and an air baffle for adjusting the proportion of air supplied by the blower to the indoor heat exchange section; and a control device controlling the refrigerant circuit and the air conditioning unit, the control device being capable of executing a hot gas heating mode, wherein a portion of the refrigerant compressed in the compressor flows through the indoor heat exchange section and the remaining portion flows through the hot gas bypass, and the air baffle is controlled such that at least a portion of the air bypasses the indoor heat exchange section when the hot gas heating mode is started and the blower is activated.

[0016] Invention Effects

[0017] According to the present invention, in hot gas heating operation, the time for the refrigerant pressure on the high-pressure side of the refrigerant circuit to reach the target pressure can be shortened, and the time for reaching the target blowing temperature and target heating capacity can be shortened, thus ensuring rapid heating performance. Attached Figure Description

[0018] Figure 1 This is an explanatory diagram illustrating an example of the system structure of an automotive air conditioning device according to an embodiment of the present invention.

[0019] Figure 2 This is an explanatory diagram showing the control device of an automotive air conditioning system according to an embodiment of the present invention.

[0020] Figure 3 This is a diagram illustrating the structure of a control device and the like in an electric vehicle (EV) according to an embodiment of the present invention.

[0021] Figure 4 This is an explanatory diagram illustrating the operation of the refrigerant circuit during hot air heating operation in an automotive air conditioning system according to an embodiment of the present invention.

[0022] Figure 5 This is a graph illustrating an example of the behavior of the outlet refrigerant pressure of the indoor heat exchanger and the air volume delivered through the indoor heat exchanger during hot air heating operation in the vehicle air conditioning device of the embodiment of the present invention and the vehicle air conditioning device of the reference example. Detailed Implementation

[0023] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same symbols in different figures indicate parts with the same function, and repeated descriptions in each figure are omitted as appropriate. In addition, the thick black lines in the refrigerant circuit 10 in the figures indicate the refrigerant flow path for high-pressure refrigerant, and the blank lines indicate the refrigerant flow path for refrigerant after pressure reduction. In addition, the dashed lines in the refrigerant circuit 10 indicate the refrigerant flow path where refrigerant does not flow.

[0024] [Structure of refrigerant circuit, etc.]

[0025] Figure 1 An example of the structure of an automotive air conditioning device 1 according to an embodiment of the present invention is shown. The example shown here is an example and is not particularly limited to a specific structure.

[0026] The vehicle air conditioning unit 1 includes a refrigerant circuit 10 and an air conditioning unit 20. The refrigerant circuit 10 includes a compressor 2; indoor heat exchangers 21 and 22 disposed inside the air conditioning unit 20; and an outdoor heat exchanger 11 disposed outside the vehicle, arranged along the refrigerant flow path. The indoor heat exchangers 21 and 22 are configured for heat exchange between the air flowing within the air conditioning unit 20 and the refrigerant, while the outdoor heat exchanger 11 is configured for heat exchange between external air and the refrigerant outside the vehicle. The indoor heat exchanger 21 heats the air, and the indoor heat exchanger 22 cools the air. Immediately downstream of the indoor heat exchanger 21, a refrigerant pressure sensor 44B is provided to detect the outlet refrigerant pressure Pci (high-pressure side refrigerant pressure) flowing out of the indoor heat exchanger 21.

[0027] Compressor 2 compresses the refrigerant and circulates it within refrigerant circuit 10. The refrigerant, after compression in compressor 2, is reduced to the required pressure via a suitably selected refrigerant flow path, for example, through a first pressure-reducing section V1, a second pressure-reducing section V2, a third pressure-reducing section V3, and a fourth pressure-reducing section V4, which function as expansion valves. Flow path switching valves 12 and 13 for switching the refrigerant flow path and check valves 14 and 15 for restricting the direction of refrigerant flow are provided in refrigerant circuit 10. A storage tank 16 for recovering liquid refrigerant and separating refrigerant gas and liquid is provided immediately upstream of compressor 2 in refrigerant circuit 10. A refrigerant pressure sensor 44A is provided between storage tank 16 and compressor 2 to detect the suction refrigerant pressure Ps (low-pressure side refrigerant pressure) drawn into compressor 2.

[0028] As described above, the air conditioning unit 20 includes indoor heat exchangers 21 and 22. Air drawn in from indoors or outdoors is passed through the indoor heat exchangers 21 and 22 and then blown out into the room by the blower 23. An air baffle 24 is provided in the air conditioning unit 20. Figure 1 As shown, when the air baffle 24 is fully open, the air introduced by the blower 23 passes through the indoor heat exchangers 21 and 22 and is blown out into the room.

[0029] Furthermore, when the air baffle 24 is fully closed, the inflow side of the indoor heat exchanger 21 is blocked, and the air introduced by the blower 23 only passes through the indoor heat exchanger 22 and is blown out into the room. Another air baffle 25 provided in the air conditioning unit 20 switches the air introduced into the blower 23 between the indoor and outdoor environments. The air baffle 25 can selectively close the air inlet 25A connected to the outside and the air inlet 25B connected to the inside, and draw in air from one of them. Alternatively, by placing the air baffle 25 in an intermediate position, air can be drawn in from both the air inlet 25A and the air inlet 25B.

[0030] Furthermore, although the example of direct heat exchange between the refrigerant and air in the external heat exchanger 11 and the indoor heat exchangers 21 and 22 described above has been explained, indirect heat exchange between the refrigerant and air can also be achieved via a heat carrier after heat exchange with the refrigerant. That is, it can also be configured such that the refrigerant absorbs heat from the air via the heat carrier, or that the refrigerant dissipates heat to the air via the heat carrier.

[0031] like Figure 1 As shown, the vehicle air conditioning unit 1 includes a heat carrier circuit 30. The heat carrier circuit 30 circulates the heat carrier via a circulation pump 31, and heats the heat carrier in a heater (ECH: Electric Coolant Heater) 32, or recovers waste heat from temperature-controlled objects such as batteries in a temperature-controlled heat exchanger 33. Furthermore, a refrigerant heat carrier heat exchanger 34 is provided in both the refrigerant circuit 10 and the heat carrier circuit 30, where heat exchange between the refrigerant and the heat carrier occurs in a flow path 34A for refrigerant flow and a flow path 34B for heat carrier flow. The heat carrier circuit 30 is configured as needed.

[0032] [Control Device]

[0033] Vehicle air conditioning unit 1 includes Figure 2 The control device 100 shown controls the refrigerant circuit 10, the air conditioning unit 20, and the heat transfer circuit 30 based on various input signals (air conditioning indicator signals, charger connection signals, etc.) and detection signals from the sensor unit 40.

[0034] The sensor unit 40 that inputs detection signals to the control device 100 includes, for example, an external gas sensor 41 that detects the external gas state such as external gas temperature and external gas humidity; a compressor current sensor 42 that detects the power consumption (energy consumption) of the compressor 2; a refrigerant temperature sensor 43 and a refrigerant pressure sensor 44 that detect the state of the refrigerant; an occupant sensor 45 that detects whether there are occupants in the vehicle interior; and an air supply temperature sensor 46 that detects the air supply temperature of the air conditioning unit 20, etc.

[0035] Specifically, the refrigerant pressure sensor 44 includes: a refrigerant pressure sensor 44A, which detects the suction refrigerant pressure Ps (low-pressure side refrigerant pressure) drawn into the compressor 2; and a refrigerant pressure sensor 44B, which detects the outlet refrigerant pressure Pci (high-pressure side refrigerant pressure) of the indoor heat exchanger 21 (see reference). Figure 1 These sensors are just one example; the sensor unit 40 also includes various sensors that detect information required by the control device 100 when performing various controls.

[0036] The controlled objects of the control device 100 are, in the refrigerant circuit 10, compressor 2, first pressure reducing unit V1, second pressure reducing unit V2, third pressure reducing unit V3, fourth pressure reducing unit V4, flow path switching valves 12 and 13, etc.; in the air conditioning unit 20, blower 23, air baffles 24 and 25, etc.; and in the heat carrier circuit 30, circulation pump 31, etc. Furthermore, the control device 100 controls the vehicle air conditioning unit 1 based on the processing results of the control device 100. In the vehicle air conditioning unit 1, the control device 100 can switch between heat absorption heating operation and hot gas heating operation. In the heat absorption heating operation, the refrigerant absorbs heat in the external heat exchanger 11. In the hot gas heating operation, instead of heat absorption in the external heat exchanger 11, the refrigerant compressed in the compressor 2 dissipates heat in the indoor heat exchanger 21 to heat the vehicle interior.

[0037] [Structure of the control unit in an electric vehicle (EV)]

[0038] like Figure 3 As shown, the control device 100 included in the vehicle air conditioning system 1 is configured as an ECU connected to various ECUs (Electronic Control Units) that control the electric vehicle EV via the vehicle network L. The control device 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, an I / F (Interface) for input / output 104, an I / F (Interface) for in-vehicle communication 105, etc., and all hardware is interconnected via a bus 106.

[0039] CPU 101 executes various programs stored in ROM 102 to control the control device 100. ROM 102 is non-volatile memory. For example, ROM 102 stores programs executed by CPU 101, data required by CPU 101 to execute programs, etc. RAM 103 is a main storage device such as DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory).

[0040] For example, RAM 103 functions as a working area used when the CPU 101 executes a program. Input / output (I / F) 104 connects to various sensors and displays installed in the EV to input data to the CPU 101 and outputs data processed by the CPU 101. In-vehicle communication (I / F) 105 connects to the vehicle network L to control data transmission and reception between other ECUs installed in the EV.

[0041] The control device 100 receives data related to the surrounding environment or the operating status of the EV via an input / output I / F 104 or a vehicle-wide I / F 105, and executes the control of the vehicle air conditioning device 1 by a program executed by the CPU 101.

[0042] A battery B is installed in the EV. The battery B is charged by connecting the charger plug PS to the battery plug BP, and the battery B supplies power to the vehicle air conditioning unit 1. When the battery plug BP and plug PS are connected, a charger connection signal is sent to the control device 100 via the vehicle network L.

[0043] [Hot gas heating operation]

[0044] Since it is difficult to absorb heat through the external heat exchanger 11 at extremely low temperatures, hot gas is used for heating. In hot gas heating operation, the refrigerant does not absorb heat in the external heat exchanger 11, but instead, part or all of the refrigerant compressed in the compressor 2 dissipates heat in the indoor heat exchanger 21 to heat the vehicle interior.

[0045] exist Figure 4 The operation of the refrigerant circuit 10 during hot gas heating operation will be explained. In this operation, a portion of the high-temperature, high-pressure refrigerant discharged from the compressor 2 passes through the indoor heat exchanger 21 and the flow path switching valve 12, is reduced to low pressure in the third pressure reducing section V3, passes through the refrigerant heat carrier heat exchanger 34, undergoes gas-liquid separation in the storage tank 16, and returns to the compressor 2. At this time, in the refrigerant circuit 10, by setting the first pressure reducing section V1 to be fully closed, the refrigerant does not flow into the external heat exchanger 11. Furthermore, by setting the fourth pressure reducing section V4 to be fully closed, the refrigerant does not flow into the indoor heat exchanger 22.

[0046] The refrigerant circuit 10 has a hot gas bypass 10V, which allows at least a portion of the refrigerant compressed in the compressor 2 to be depressurized and returned to the compressor 2 without passing through the indoor heat exchanger 21 and the external heat exchanger 11. In the hot gas bypass 10V, a portion of the high-temperature, high-pressure refrigerant branches off at a bifurcation point P1 immediately downstream of the compressor 2, is depressurized in the second depressurization section V2, and merges with the low-pressure refrigerant depressurized in the third depressurization section V3 at a confluence point P2 immediately upstream of the storage tank 16.

[0047] By setting up such a hot gas bypass 10V, the gaseous refrigerant passing through the hot gas bypass 10V can be mixed with the liquid refrigerant condensed by heat dissipation in the indoor heat exchanger 21, and then returned to the compressor 2 after becoming a gas-rich refrigerant. Furthermore, by increasing the refrigerant flow rate in the hot gas bypass 10V, the heat dissipation in the indoor heat exchanger 21 can be suppressed. The refrigerant flow rate in the hot gas bypass 10V is regulated by opening and closing the second pressure reducing unit V2, thus maintaining a balance between the heat dissipation of the refrigerant circuit 10 and the heat input to the compressor 2. In other words, the second pressure reducing unit V2 functions as a flow regulating unit that adjusts the flow rate of the refrigerant flowing in the hot gas bypass 10V.

[0048] During hot air heating operation, the refrigerant flow is depressurized in the third pressure reducing section V3 in the flow path via the indoor heat exchanger 21. Therefore, its upstream side becomes high-pressure refrigerant, and its downstream side becomes low-pressure refrigerant. At this time, it is important that no heat exchange occurs in the refrigerant heat carrier heat exchanger 34 in the low-pressure side flow path to maintain heating capacity. Moreover, in the air conditioning unit 20, the air introduced by the blower 23 is heated by heat dissipation in the indoor heat exchanger 21 and blown into the vehicle interior.

[0049] Furthermore, although the refrigerant flow diagram for the refrigerant circuit 10 during heat absorption and heating operation is omitted, in the refrigerant circuit 10 during heat absorption and heating operation, the second pressure reducing section V2, the third pressure reducing section V3, the fourth pressure reducing section V4, and the flow path switching valve 12 are all closed. On the other hand, the flow path switching valve 13 is fully open, and the first pressure reducing section V1 is open.

[0050] Furthermore, during heat absorption and heating operation, the high-temperature, high-pressure refrigerant discharged from the compressor 2 passes through the indoor heat exchanger 21 within the air conditioning unit 20, where it is depressurized in the first pressure reduction section V1. The low-pressure refrigerant then passes through the external heat exchanger 11, and via the flow path switching valve 13, check valve 14, and storage tank 16, before returning to the compressor 2. At this time, the high-pressure refrigerant flowing from the compressor 2 condenses and dissipates heat in the indoor heat exchanger 21, is depressurized into low-pressure refrigerant in the first pressure reduction section V1, absorbs heat and evaporates in the external heat exchanger 11, and returns to the compressor 2. Moreover, in the air conditioning unit 20, the air introduced by the blower 23 is heated by heat dissipation in the indoor heat exchanger 21 and blown into the vehicle interior.

[0051] [Adjustment of the high-pressure side refrigerant in the refrigerant circuit during hot gas heating operation]

[0052] When the vehicle air conditioning unit 1 is in operation for hot air heating, the control device 100 performs the following control when it starts to operate for hot air heating (including the start of hot air heating operation and the switch from heat absorption heating operation to hot air heating operation).

[0053] That is, after the control device 100 starts the hot air heating operation, it stops the drive of the blower 23 and limits the heat dissipation in the indoor heat exchanger 21. At the same time, it drives the compressor 2 at a predetermined high speed (e.g., maximum speed) to make the refrigerant pressure on the high-pressure side of the refrigerant circuit 10 (in this embodiment, it is set as the outlet refrigerant pressure Pci of the indoor heat exchanger 21) reach the target pressure (target outlet refrigerant pressure PCO). Then, when the outlet refrigerant pressure Pci rises to the specified pressure, it starts driving the blower 23 and suppresses excessive rise of the outlet refrigerant pressure Pci while controlling the air baffle 24.

[0054] The operation of the outlet refrigerant pressure Pci when the control device 100 performs the above control will be explained below by comparing with a reference example. Figure 5 The diagram shows an example of the relationship between the outlet refrigerant pressure Pci and the air volume delivered through the indoor heat exchanger 21 during the aforementioned control process in the vehicle air conditioning unit 1 of this embodiment and the reference example. Additionally, in Figure 5 In the example, although the operation of compressor 2 is not shown, in this embodiment and the reference example, compressor 2 is driven with its target speed as the maximum value.

[0055] (Control method for reference)

[0056] exist Figure 5In the example, the outlet refrigerant pressure Pci when the control method of the reference example is started to be executed is set as Pci_ref, and the air volume passing through the indoor heat exchanger 21 is set as AF_ref, both of which are represented by dashed lines.

[0057] When the hot air heating operation begins, the control device 100 drives the compressor 2 at the target speed as the maximum value. At this time, the drive of the blower 23 is stopped, and no air is supplied to the indoor heat exchanger 21, thereby limiting the heat dissipation in the indoor heat exchanger 21. By continuously driving the compressor 2 in this state, as Figure 5 As shown, the outlet refrigerant pressure Pci_ref rises.

[0058] During this period, the control device 100 acquires the outlet refrigerant pressure Pci_ref detected by the refrigerant pressure sensor 44B at predetermined intervals. When the acquired outlet refrigerant pressure Pci_ref is detected to be a predetermined pressure Pci_th lower than the target outlet refrigerant pressure PCO, the control device 100 drives the blower 23 and begins to supply air to the indoor heat exchanger 21. At this time, the control device 100 drives the blower 23 at its minimum speed and controls it so that the air baffle 24 is fully open. Therefore, the minimum air supply volume is introduced into the air conditioning unit 20 according to the minimum speed of the blower 23. After passing through the indoor heat exchanger 22, the introduced air is supplied through the air baffle 24 so that it passes entirely through the indoor heat exchanger 21. Figure 5 (AF_ref).

[0059] Therefore, in the indoor heat exchanger 21, since heat is dissipated from the refrigerant to all the air introduced into the air conditioning unit 20 via the blower 23, the outlet refrigerant pressure Pci_ref temporarily decreases. That is, after the moment T1 when the blower 23 starts to drive, the outlet refrigerant pressure Pci_ref temporarily drops.

[0060] Subsequently, by continuously driving compressor 2 at maximum speed to raise the outlet refrigerant pressure Pci again, the time required for the outlet refrigerant pressure Pci_ref to reach the target outlet refrigerant pressure PCO becomes longer than the amount of decrease in outlet refrigerant pressure Pci_ref when the blower 23 is started. Therefore, the time required for the outlet temperature to reach the target outlet temperature and the time required for the heating capacity to reach the target heating capacity also become longer, failing to ensure rapid heating and compromising user comfort.

[0061] (Control method of this embodiment)

[0062] Therefore, in this embodiment, when the control device 100 starts executing the hot air heating mode and starts the blower 23, it controls the air baffle 24 in such a way that at least a portion of the air bypasses the indoor heat exchanger 21. That is, when the blower 23 is driven, the opening degree of the air baffle 24 is controlled, and the proportion of air directed toward the indoor heat exchanger 21 in the air introduced into the air conditioning unit 20 through the blower 23 is adjusted, thereby suppressing an excessive rise in the outlet refrigerant pressure Pci. This will be explained in detail below.

[0063] When the hot air heating operation begins, the control device 100 drives the compressor 2 at the target speed as the maximum value. At this time, the drive of the blower 23 is stopped, and no air is supplied to the indoor heat exchanger 21, thereby limiting the heat dissipation in the indoor heat exchanger 21. By continuously driving the compressor 2 in this state, as Figure 5 As shown, the outlet refrigerant pressure Pci rises.

[0064] During this period, the control device 100 acquires the outlet refrigerant pressure Pci detected by the refrigerant pressure sensor 44B at predetermined intervals. When the acquired outlet refrigerant pressure Pci is detected to be a predetermined pressure Pci_th lower than the target outlet refrigerant pressure PCO, the control device 100 drives the blower 23 and begins to supply air to the indoor heat exchanger 21. At this time, the control device 100 drives the blower 23 at minimum speed and controls the opening of the air damper 24. By driving the blower 23 at minimum speed when starting, the airflow supplied to the indoor heat exchanger 21 can be set to a minimum air volume, thereby minimizing the heat dissipation in the indoor heat exchanger 21.

[0065] exist Figure 5 In the example shown, the control device 100 adjusts the opening of the air damper 24 from fully open to a semi-closed position, controlling it to deliver approximately half of the air supplied by the blower 23 to the indoor heat exchanger 21. Therefore, based on the minimum operating speed of the blower 23, a minimum airflow is introduced into the air conditioning unit 20. This introduced air, after passing through the indoor heat exchanger 22, is then delivered through the air damper 24, with approximately half of the air passing through the indoor heat exchanger 21. Figure 5 (AF).

[0066] Therefore, in the indoor heat exchanger 21, heat is dissipated from the refrigerant to approximately half of the air in the minimum airflow introduced into the air conditioning unit 20 by the blower 23. Simultaneously, since the compressor 2 is continuously driven at maximum speed, the outlet refrigerant pressure Pci rises; however, after the start of the blower 23 at time T1, the outlet refrigerant pressure Pci rises slightly more slowly compared to before time T1. The outlet refrigerant pressure Pci rises slightly more slowly compared to before time T1, and reaches the target outlet refrigerant pressure PCO at time T2.

[0067] After time T2, the outlet refrigerant pressure Pci becomes a pressure slightly higher than the target outlet refrigerant pressure PCO, but this pressure is within the range permissible as the target outlet refrigerant pressure PCO. Thus, in this embodiment, the outlet refrigerant pressure Pci reaches the target outlet refrigerant pressure PCO at time T2, thereby shortening the time required for the outlet refrigerant pressure Pci to reach the target outlet refrigerant pressure PCO.

[0068] In addition, Figure 5 The example described illustrates adjusting the opening of the air damper 24 from fully open to fully closed when the blower 23 is started. However, the opening of the air damper 24 when the blower 23 is started and subsequent adjustments can be made appropriately. For example, when the blower 23 is started, the air damper 24 can be set to fully closed to block the suction side of the indoor heat exchanger 21 and cut off the air supply path to the indoor heat exchanger 21. Then, the air damper 24 can be driven linearly or in stages in the opening direction according to the outlet refrigerant pressure Pci, thereby adjusting the air volume to the indoor heat exchanger 21.

[0069] In this way, when the blower 23 is started, it can prevent all the air supplied from the blower 23 from being rapidly introduced into the indoor heat exchanger 21, suppress the rapid increase in heat dissipation in the indoor heat exchanger 21, and reduce the drop in outlet refrigerant pressure Pci after the blower 23 is started.

[0070] Furthermore, when the air damper 24 is driven linearly or intermittently from fully closed to open according to the outlet refrigerant pressure Pci, the air damper 24 is controlled in a manner that keeps the decrease (reduction amount) of the outlet refrigerant pressure Pci within a specified range. This specified range can be preset to ensure rapid heating performance, i.e., the range allowed based on the target time required for the outlet refrigerant pressure Pci to reach the target outlet refrigerant pressure PCO. Therefore, by setting the decrease in outlet refrigerant pressure Pci to an allowable range, the time required for the outlet refrigerant pressure Pci to reach the target outlet refrigerant pressure PCO can be shortened, and the time required for the outlet temperature to reach the target outlet temperature can also be shortened.

[0071] Thus, in this embodiment, when the hot gas heating operation begins, the heat dissipation in the indoor heat exchanger 21 is adjusted by controlling the opening of the air damper 24 in conjunction with the drive of the blower 23. This suppresses a rapid and excessive rise in the outlet refrigerant pressure Pci, prevents overshoot exceeding the permissible range, and thus prevents the compressor 2 from stopping due to high-pressure protection. Furthermore, it shortens the time required for the outlet refrigerant pressure Pci to reach the target outlet refrigerant pressure PCO.

[0072] In addition, by shortening the time it takes for the outlet refrigerant pressure Pci to reach the target outlet refrigerant pressure PCO, it is possible to simultaneously shorten the time required for the outlet temperature to reach the target outlet temperature and the time required for the heating capacity to reach the target heating capacity, thereby ensuring rapid heating and improving user comfort.

[0073] Specifically, by driving the blower 23 at its minimum speed when starting and setting the airflow from the air baffle 24 to the indoor heat exchanger 21 to a minimum volume, the heat loss in the indoor heat exchanger 21 is suppressed as much as possible, and the decrease in the outlet refrigerant pressure Pci is also suppressed as much as possible. This shortens the time it takes for the outlet refrigerant pressure Pci to reach the target outlet refrigerant pressure PCO, the time it takes for the outlet temperature to reach the target outlet temperature, and the time it takes for the heating capacity to reach the target heating capacity, thus minimizing the impact on user comfort.

[0074] Furthermore, as described above, in this embodiment, an example of using the outlet refrigerant pressure Pci and the target outlet refrigerant pressure PCO of the indoor heat exchanger 21 as the high-pressure side refrigerant pressure and its target pressure has been explained. However, the discharge pressure and the target discharge pressure of the compressor 2 can also be used as the high-pressure side refrigerant pressure, for example.

[0075] As described above, according to this embodiment, during hot gas heating operation, the time it takes for the refrigerant pressure on the high-pressure side of the refrigerant circuit to reach the target pressure can be shortened, and the time to reach the target blowing temperature and target heating capacity can be shortened, thus ensuring rapid heating performance.

[0076] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the specific structure is not limited to these embodiments. Even design changes that do not depart from the scope of the present invention are included in the present invention.

[0077] Symbol Explanation

[0078] 1: Vehicle air conditioning unit; 2: Compressor; 10: Refrigerant circuit; 10V: Hot gas bypass.

[0079] 11: External heat exchanger; 12, 13: Flow path switching valve; 14, 15: Check valve.

[0080] 16: Storage tank; 20: Air conditioning unit; 21, 22: Indoor heat exchanger

[0081] 23: Blower; 24, 25: Air baffle; 25A, 25B: Air inlet

[0082] 30: Heat transfer circuit; 31: Circulating pump; 33: Temperature-regulating heat exchanger

[0083] 34: Refrigerant heat transfer medium heat exchanger; 34A, 34B: Flow path; 40: Sensor section

[0084] 41: External gas sensor; 42: Compressor current sensor; 43: Refrigerant temperature sensor

[0085] 44, 44A, 44B: Refrigerant pressure sensor; 45: Occupant sensor; 46: Supply air temperature sensor

[0086] 100: Control device.

Claims

1. A vehicle air conditioning unit, comprising: A refrigerant circuit having a compressor, an indoor heat exchange section, an external heat exchange section, and a hot gas bypass, wherein the hot gas bypass allows at least a portion of the refrigerant compressed in the compressor to be depressurized and returned to the compressor without passing through the indoor heat exchange section and the external heat exchange section; An air conditioning unit, wherein the indoor heat exchange section is disposed inside, and the air conditioning unit has a blower for supplying air to the interior and an air baffle for adjusting the proportion of air supplied by the blower to the indoor heat exchange section. as well as A control device that controls the refrigerant circuit and the air conditioning unit. The control device is capable of executing a hot gas heating mode. The hot gas heating mode causes a portion of the refrigerant compressed in the compressor to flow through the indoor heat exchange section, while the remaining portion flows through the hot gas bypass. When the hot air heating mode is started and the blower is activated, the air baffle is controlled in such a way that at least a portion of the air bypasses the indoor heat exchange section.

2. The vehicle air conditioning device as described in claim 1, characterized in that, The control device starts the blower at minimum speed.

3. The vehicle air conditioning device as described in claim 1 or 2, characterized in that, The refrigerant circuit includes a pressure sensor that detects the pressure of the refrigerant flowing through the indoor heat exchange section. When the blower is started, the control device controls the air baffle in such a way that the decrease in pressure detected by the pressure sensor is within a specified range.

4. The vehicle air conditioning device as described in claim 1 or 2, characterized in that, When the blower is started, the control device controls the air baffle in a manner that cuts off the air supply path toward the indoor heat exchange section.

Images