Vehicle air conditioning device

Abstract

The present invention provides a vehicle air-conditioning device which ensures the heat dissipation amount required along with the increase of the heating load, stably continues a hot-gas heating mode and achieves a desired blow-out temperature, thereby improving the comfort of an occupant. In a vehicle air-conditioning device provided with a refrigerant circuit, an air-conditioning unit, and a control device for controlling the refrigerant circuit and the air-conditioning unit, it is possible to execute a hot-air heating mode in which a portion of a refrigerant compressed by a compressor is bypassed and returned to the compressor, and a hot-air heating mode in which the refrigerant compressed by the compressor is bypassed and returned to the compressor. In the hot-air heating mode, when it is determined that the heating load has increased, control is performed so as to enlarge the rising range of the target rotational speed of the compressor, and when it is determined that the heating load has increased during execution of the hot-air heating mode, control is performed so as to enlarge the rising range of the target rotational speed of the compressor.

Description

TECHNICAL FIELD

[0001] The present application relates to a vehicle air-conditioner. BACKGROUND

[0002] In recent years, hybrid vehicles, electric vehicles, and the like in which a traveling motor is driven by electric power supplied from a battery mounted on a vehicle are becoming widespread. As a vehicle air-conditioner mounted on such a vehicle, a vehicle air-conditioner using a heat pump (refrigerant circuit) as a heat source is known.

[0003] In a vehicle air-conditioner using a heat pump, during heating operation, an outside heat exchanger such as an outdoor heat exchanger disposed outside the vehicle cabin functions as a heat absorber to obtain a heating heat source from outside air or the like (absorption heating). Therefore, if the outside air temperature becomes extremely low, it is difficult to absorb heat from the outside air or the like, and the heating capacity is greatly reduced. In contrast, as a heating method effective in an extremely low temperature environment, heat gas heating using high-temperature and high-pressure refrigerant discharged from a compressor without absorbing heat from outside air or the like is known.

[0004] For example, in the vehicle air-conditioner of Patent Literature 1, a heat gas heating mode is executed in which a part of high-temperature and high-pressure refrigerant discharged from the compressor is depressurized after flowing through a bypass passage and then returned to the compressor, and the remaining refrigerant is depressurized after heat-exchanging with air blown into the vehicle cabin in an indoor heat exchanger, and then returned to the compressor without passing through the outside heat exchanger. PRIOR ART DOCUMENT PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2023-46604 SUMMARY PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] The above heat gas heating mode is an operation mode in which air is heated using heat generated by the operation of the compressor, and the amount of work (input heat) of the compressor becomes the heating capacity (heat dissipation capacity) of the air in the indoor heat exchanger. Therefore, in the vehicle air-conditioner, in order to stably operate the heat gas heating mode, each structure is controlled so that the input heat of the compressor and the heat dissipation amount in the indoor heat exchanger are balanced.

[0007] However, in the case where the flow rate of the refrigerant is constant, the heat dissipation amount in the indoor heat exchanger depends on the air volume of the air blown by the blower and passing through the indoor heat exchanger, and thus the heat dissipation amount in the indoor heat exchanger varies depending on the driving state of the blower. That is, if the blower is driven at the maximum speed, the air passing through the indoor heat exchanger is at the maximum air volume, and the heat dissipation amount in the indoor heat exchanger is also the maximum.

[0008] Therefore, for example, when the blower is driven at maximum speed, if the heating load increases, the heat input to the compressor increases, but the heat dissipation in the indoor heat exchanger cannot increase. Thus, the heat input becomes greater than the heat dissipation, making it impossible to maintain a balance between the two. In this situation, the pressure and temperature of the refrigerant on the compressor's suction side (low-pressure side) rise, and simultaneously, the pressure and temperature of the refrigerant on the discharge side (high-pressure side) also rise. Therefore, the pressure of the refrigerant on the discharge side (high-pressure side) may exceed its upper limit, causing the hot air heating mode to operate unstablely and the vehicle's air conditioning system to stop.

[0009] On the other hand, in order to balance the heat input to the compressor and the heat dissipation in the indoor heat exchanger, if the heat input to the compressor is suppressed, the desired heating cannot be achieved in accordance with the increase in heating load, and there will be adverse situations such as the inability to raise the blow-out temperature to the desired temperature.

[0010] The present invention was made in view of the following situation, and its object is to improve the comfort of passengers by ensuring the heat dissipation required with the increase of heating load, so as to stably maintain the hot air heating mode and achieve the desired blow-out temperature. Methods for solving problems

[0011] One aspect of the present invention provides an air conditioning device for a vehicle, comprising: a refrigerant circuit including: a compressor; an indoor heat exchange section; an external heat exchange section; and a hot gas bypass for depressurizing at least a portion of the refrigerant compressed by the compressor and returning it to the compressor without passing through the indoor heat exchange section and the external heat exchange section; an air conditioning unit having the indoor heat exchange section internally disposed therein, including: an adjusting damper for adjusting the ratio of indoor to outdoor air introduced into the unit; and a blower for supplying air into the unit; and a control device for controlling the refrigerant circuit and the air conditioning unit to execute a hot gas heating mode, wherein in the hot gas heating mode, a portion of the refrigerant compressed by the compressor flows in the hot gas bypass and returns to the compressor, and the remaining refrigerant is dissipated in the indoor heat exchange section, wherein during the execution of the hot gas heating mode, the control device controls the compressor to increase its target speed range if it determines that the heating load has increased. Invention Effects

[0012] According to the present invention, by ensuring the required heat dissipation accompanying the increase in heating load, the hot air heating mode can be stably maintained and the desired blow-out temperature can be achieved, thereby improving the comfort of the occupants. Attached Figure Description

[0013] Figure 1 This is an explanatory diagram illustrating an example of the system structure of a vehicle air conditioning device according to an embodiment of the present invention. Figure 2 This is an explanatory diagram showing the control device of a vehicle air conditioning system according to an embodiment of the present invention. Figure 3 This diagram illustrates the configuration of a control device or the like in an electric vehicle (EV) according to an embodiment of the present invention. Figure 4 This is an explanatory diagram illustrating the operation of the refrigerant circuit in the hot air heating mode of the vehicle air conditioning unit according to an embodiment of the present invention. Figure 5 This is a flowchart illustrating the process of handling an increase in heating load during the execution of a hot air heating mode in a vehicle air conditioning unit according to an embodiment of the present invention. Detailed Implementation

[0014] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same reference numerals in different figures denote 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 represent the refrigerant flow path of high-pressure refrigerant, and the hollow lines represent the refrigerant flow path of refrigerant after pressure reduction. Furthermore, the dashed lines in the refrigerant circuit 10 represent the refrigerant flow path where no refrigerant is flowing.

[0015] [Structure of refrigerant circuit, etc.] Figure 1 The present invention illustrates a structural example of a vehicle air conditioning unit 1 according to an embodiment of the present invention. The structural example shown here is merely an example and does not specifically limit the specific structure.

[0016] 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, all arranged along the refrigerant flow path. The indoor heat exchangers 21 and 22 are configured to exchange heat between the air flowing inside the air conditioning unit 20 and the refrigerant, while the outdoor heat exchanger 11 is configured to exchange heat between the outside air and the refrigerant outside the vehicle. The indoor heat exchanger 21 is used for heating the air, and the indoor heat exchanger 22 is used for cooling the air. A refrigerant pressure sensor 44B for detecting the outlet refrigerant pressure Pci (high-pressure side refrigerant pressure) from the indoor heat exchanger 21 and a refrigerant temperature sensor 43B for detecting the outlet refrigerant temperature Tc (high-pressure side refrigerant temperature) are disposed immediately downstream of the indoor heat exchanger 21.

[0017] Compressor 2 compresses the refrigerant and circulates it within the refrigerant circuit 10. The refrigerant, compressed by compressor 2, is depressurized to the desired pressure via, for example, expansion valves such as 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. The refrigerant circuit 10 is equipped with 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.

[0018] A liquid receiver 16 is provided in the refrigerant circuit 10, located upstream of the compressor 2, to recover liquid refrigerant and separate refrigerant gas and liquid. A refrigerant pressure sensor 44A is provided between the liquid receiver 16 and the compressor 2 to detect the suction refrigerant pressure Ps (low-pressure side refrigerant pressure) drawn into the compressor 2, and a refrigerant temperature sensor 43A to detect the suction refrigerant temperature Ts (low-pressure side refrigerant temperature).

[0019] As described above, the air conditioning unit 20 includes indoor heat exchangers 21 and 22, a blower 23 for introducing air from inside or outside the vehicle, and a damper 24 for adjusting the proportion of air introduced by the blower 23 passing through the indoor heat exchangers 21. Furthermore, the air conditioning unit 20 includes a damper 25 positioned upstream of the blower 23 in the airflow direction to adjust the ratio of indoor air (internal air) to outdoor air (external air) introduced into the air conditioning unit 20.

[0020] In the air conditioning unit 20, air introduced by the blower 23 is blown into the vehicle interior through the indoor heat exchangers 21 and 22. Figure 1 When the regulating damper 24 is fully open, the air introduced by the blower 23 passes through the indoor heat exchanger 22 and then is blown into the room through the indoor heat exchanger 21. Furthermore, when the regulating damper 24 is fully closed, the inflow side of the indoor heat exchanger 21 is sealed off, and the air introduced by the blower 23 is blown into the vehicle interior only through the indoor heat exchanger 22.

[0021] In the air conditioning unit 20, by selectively closing the air inlet 25A connected to the outside and the air inlet 25B connected to the inside by adjusting the damper 25, either outside air or inside air can be drawn in. Furthermore, in the air conditioning unit 20, by positioning the damper 25 at a desired position between the air inlets 25A and 25B, either inside air or outside air can be drawn in at a desired ratio from both air inlets 25A and 25B.

[0022] Furthermore, in the aforementioned external heat exchanger 11 and indoor heat exchangers 21 and 22, an example of direct heat exchange between the refrigerant and air has been described. However, the refrigerant and air can also exchange heat indirectly via a heat medium that has exchanged heat with the refrigerant. That is, it can also be configured such that the refrigerant absorbs heat from the air via a heat medium or releases heat from the refrigerant to the air via a heat medium.

[0023] like Figure 1 As shown, the vehicle air conditioning unit 1 includes a heat medium circuit 30. The heat medium circuit 30 circulates the heat medium via a circulation pump 31, heats the heat medium via a heater (ECH: Electric Coolant Heater) 32, or recovers waste heat from a temperature-regulated object such as a battery via a temperature-regulated object heat exchanger 33. Furthermore, a refrigerant heat medium heat exchanger 34 is provided in both the refrigerant circuit 10 and the heat medium circuit 30, allowing heat exchange between the refrigerant and the heat medium via a flow path 34A for refrigerant flow and a flow path 34B for heat medium flow. The heat medium circuit 30 is configured according to requirements.

[0024] [Control Device] Vehicle air conditioning unit 1 has Figure 2 The control device 100 shown. The control device 100 controls the refrigerant circuit 10, the air conditioning unit 20 and the heat medium circuit 30 based on various input signals 60 (air conditioning indicator signal, charger connection signal, etc.) and detection signals from the sensor unit 40.

[0025] The sensor unit 40 that inputs detection signals to the control device 100 includes, for example: an external air sensor 41 for detecting external air conditions such as external air temperature Tam and external air humidity; a compressor current sensor 42 for detecting the power consumption (energy consumption) of the compressor 2; a refrigerant temperature sensor 43 and a refrigerant pressure sensor 44 for detecting the state of the refrigerant; an occupant sensor 45 for detecting the presence or absence of occupants in the vehicle interior; a supply air temperature sensor 46 for detecting the supply air temperature of the air conditioning unit 20; and an internal air sensor 47 for detecting the state of the vehicle interior such as internal air temperature and internal air humidity; and so on.

[0026] Specifically, the refrigerant temperature sensor 43 includes: a refrigerant temperature sensor 43A, which detects the intake refrigerant temperature Ts (low-pressure side refrigerant temperature) of the compressor 2; and a refrigerant temperature sensor 43B, which detects the outlet refrigerant temperature Tc (high-pressure side refrigerant temperature) of the indoor heat exchanger 21 (see reference). Figure 1 ).

[0027] In addition, the refrigerant pressure sensor 44 includes: a refrigerant pressure sensor 44A, which detects the suction refrigerant pressure Ps (low-pressure side refrigerant pressure) of 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 one example; the sensor unit 40 is equipped with various sensors that detect information required by the control device 100 to perform various controls.

[0028] The objects controlled by the control device 100 are, in the refrigerant circuit 10, the compressor 2, the first pressure reducing unit V1, the second pressure reducing unit V2, the third pressure reducing unit V3, the fourth pressure reducing unit V4, and the flow path switching valves 12 and 13, etc.; in the air conditioning unit 20, the blower 23 and the regulating dampers 24 and 25, etc.; and in the heat medium circuit 30, the circulating 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 execute various operating modes, including a heat absorption heating mode and a hot gas heating mode. In the heat absorption heating mode, the refrigerant absorbs heat in the external heat exchanger 11; in the hot gas heating mode, the refrigerant does not absorb heat in the external heat exchanger 11, but dissipates heat in the indoor heat exchanger 21 after being compressed by the compressor 2, thereby heating the vehicle interior.

[0029] [Structure of the control unit in an electric vehicle (EV)] like Figure 3 As shown, the control device 100 of the vehicle air conditioning unit 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) 104 for input / output, and an I / F (Interface) 105 for in-vehicle communication, etc., and all hardware is interconnected via a bus 106.

[0030] 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).

[0031] For example, RAM 103 functions as a working area used when the CPU 101 executes a program. I / O I / F 104 connects to various sensors and monitors installed in the EV, inputting data to the CPU 101 and outputting data processed by the CPU 101. I / O I / F 105, used for in-vehicle communication, connects to the vehicle network L to control data transmission and reception with other ECUs installed in the EV.

[0032] The control device 100 receives data related to the surrounding environment or the operating status of the EV via the input / output I / F 104 and the in-vehicle universal I / F 105, and then executes the control of the vehicle air conditioning device 1 through the program executed by the CPU 101.

[0033] The EV is equipped with a battery B. The battery B is charged by connecting the charger plug PS to the battery slot BP, and the battery B supplies power to the vehicle's air conditioning unit 1. The connection status of the plug PS and the battery slot BP is sent to the control unit 100 via the vehicle network L as a charger connection signal.

[0034] [Hot Gas Heating Mode] At extremely low temperatures, it is difficult to absorb heat using the external heat exchanger 11; therefore, a hot air heating mode is used. The hot air heating mode operates as follows: instead of allowing the refrigerant to absorb heat in the external heat exchanger 11, some or all of the refrigerant compressed by the compressor 2 dissipates heat in the indoor heat exchanger 21, thereby heating the vehicle interior. In other words, the hot air heating mode utilizes the workload of the compressor 2 to heat the air supplied to the indoor heat exchanger 21.

[0035] exist Figure 4The operation of the refrigerant circuit 10 in the hot gas heating mode will be explained below. 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, and is reduced in pressure by the third pressure reducing section V3 to become low-pressure refrigerant. It then passes through the refrigerant heat medium heat exchanger 34, undergoes gas-liquid separation by the liquid receiver 16, and returns to the compressor 2. At this time, in the refrigerant circuit 10, by fully closing the first pressure reducing section V1, the refrigerant is prevented from flowing to the external heat exchanger 11. Furthermore, by fully closing the fourth pressure reducing section V4, the refrigerant is prevented from flowing to the indoor heat exchanger 22.

[0036] The refrigerant circuit 10 has a hot gas bypass 10V, which depressurizes at least a portion of the refrigerant compressed by the compressor 2 and returns it to the compressor 2 without passing through the indoor heat exchanger 21 and the external heat exchanger 11. In the hot gas bypass 10V, at a branch point P1 immediately downstream of the compressor 2, a portion of the high-temperature, high-pressure refrigerant branches off, depressurizes through the second depressurization section V2, and merges with the low-pressure refrigerant depressurized by the third depressurization section V3 at a confluence point P2 immediately upstream of the receiver 16.

[0037] By setting up a hot gas bypass 10V, the gaseous refrigerant passing through the hot gas bypass 10V can be mixed with the liquid refrigerant that has condensed due to heat dissipation in the indoor heat exchanger 21, becoming a gas-rich refrigerant that returns to the compressor 2. Furthermore, by increasing the flow rate of the refrigerant flowing through the hot gas bypass 10V, the heat dissipation in the indoor heat exchanger 21 can be suppressed. By opening and closing the second pressure reducing unit V2, the flow rate of the refrigerant flowing through the hot gas bypass 10V is adjusted, thereby maintaining a balance between the heat dissipation (released energy of the refrigerant) Qout of the refrigerant circuit 10 and the input heat (acquired energy of the refrigerant) Qin 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.

[0038] In hot air heating mode, the refrigerant flowing in the refrigerant circuit 10 is depressurized by the third pressure reducing section V3 in the flow path via the indoor heat exchanger 21. Therefore, the refrigerant upstream of the third pressure reducing section V3 becomes high-pressure refrigerant, and the refrigerant downstream of the third pressure reducing section V3 becomes low-pressure refrigerant. At this time, it is important that no heat exchange occurs in the refrigerant heat medium 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.

[0039] [Heat Absorption Mode] In the heat absorption and heating mode, in the refrigerant circuit 10, the refrigerant absorbs heat from the external air, which is the object of heat absorption, by flowing the refrigerant in the external heat exchanger 11, as follows, thereby obtaining a heat source for heating. Furthermore, the flow of refrigerant in the refrigerant circuit 10 in the heat absorption and heating mode is not illustrated.

[0040] In the heat absorption and heating mode, the second pressure reducing unit V2, the third pressure reducing unit V3, the fourth pressure reducing unit V4, and the flow path switching valve 12 are all fully closed in the refrigerant circuit 10. On the other hand, the flow path switching valve 13 is fully open, and the first pressure reducing unit V1 is open.

[0041] Furthermore, in the heat absorption and heating mode, 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 by the first pressure reducing section V1. The low-pressure refrigerant then passes through the external heat exchanger 11, via the flow path switching valve 13, the check valve 14, and the receiver 16, returning to the compressor 2. At this time, the high-pressure refrigerant from the compressor 2 condenses and dissipates heat in the indoor heat exchanger 21, and is depressurized by the first pressure reducing section V1 to become low-pressure refrigerant. It then absorbs heat and evaporates in the external heat exchanger 11 before returning to the compressor 2. Additionally, in the air conditioning unit 20, the air introduced by the blower 23 is heated by the heat dissipation in the indoor heat exchanger 21 and blown into the vehicle interior.

[0042] [Control processing when heating load increases as controlled by the control device] The following describes the control of the control device 100 when heating is being performed in the vehicle air conditioning unit 1 of this embodiment, and in particular, the control when the heating load HL increases during the execution of the hot air heating mode.

[0043] When the vehicle interior is heated by the vehicle air conditioning unit 1, the control device 100 executes either a heat absorption heating mode or a hot air heating mode based on the external environment, such as the outside air temperature Tam, and the set temperature Tset. The hot air heating mode has a stronger heating capacity than the heat absorption heating mode; therefore, in the control device 100, the heat absorption heating mode is typically executed when the outside air temperature Tam is above a specified temperature (e.g., -10°C), and the hot air heating mode is executed in extremely low-temperature environments where the outside air temperature Tam is below the specified temperature.

[0044] When the hot air heating mode is activated, the control device 100 drives the compressor 2 at maximum speed to maximize the heat input to the refrigerant in the compressor 2 in order to achieve the target value for the high-pressure side refrigerant pressure (e.g., outlet refrigerant pressure Pci). Then, when the high-pressure side refrigerant pressure reaches the target value (stabilization period), the control device 100 controls the various structures of the vehicle air conditioning system 1 to ensure that the heat input to the compressor 2, Qin, is approximately equal to the heat dissipation, Qout, in the indoor heat exchanger 21. This allows the hot air heating mode to be stably maintained.

[0045] Here, with the refrigerant flow rate into the indoor heat exchanger 21 constant, the heat dissipation Qout of the indoor heat exchanger 21 varies depending on the temperature and airflow Af of the air passing through the indoor heat exchanger 21.

[0046] (Regarding the temperature of the air passing through the indoor heat exchanger 21) As described above, the hot air heating mode is used in extremely low-temperature environments where the outside air temperature Tam is lower than a specified temperature. Therefore, if a large amount of outside air is drawn into the vehicle interior, it may be difficult to maintain the desired temperature inside the vehicle. On the other hand, if only the internal air is circulated within the vehicle interior, the carbon dioxide concentration inside the vehicle interior will increase. Therefore, the control device 100 controls the regulating damper 25 to achieve a predetermined fixed ratio (e.g., 30% outside air and 70% internal air) to maintain the temperature of the air drawn into the air conditioning unit 20 within a certain temperature range, while keeping the temperature inside the vehicle interior approximately at the target temperature (the aforementioned stabilization period).

[0047] (Regarding the airflow Af through the indoor heat exchanger 21) When the control device 100 predicts an increase in the heating load HL and determines that the heating load HL has increased, it controls the airflow to increase the target blowing temperature TAO into the vehicle interior by fully opening the regulating damper 24 and using the blower 23 to ensure that all air drawn into the air conditioning unit 20 passes through the indoor heat exchanger 21. Therefore, the airflow Af through the indoor heat exchanger 21 depends on the driving state of the blower 23. The greater the airflow delivered by the blower 23, the greater the airflow Af through the indoor heat exchanger 21 and the greater the heat dissipation Qout in the indoor heat exchanger 21. That is, when the refrigerant flow rate through the indoor heat exchanger 21 is constant, by driving the blower 23 at its maximum speed, the airflow Af and the heat dissipation Qout in the indoor heat exchanger 21 are maximized.

[0048] The following is based on Figure 5 The flowchart illustrates the control of the vehicle air conditioning unit 1 control device 100 in this embodiment when the heating load HL increases during the execution of the hot air heating mode.

[0049] In the vehicle air conditioning unit 1, when the hot air heating mode is being executed and is in a stable state, the control device 100 monitors the changes in the heating load HL in order to maintain the stable operation of the hot air heating mode.

[0050] For example, the heating load HL may change under the following circumstances: when the user changes the set temperature Tset, or when external disturbances occur, such as when a vehicle exits a tunnel and the temperature of the outside air drawn into the air conditioning unit 20 drops sharply, causing the control device 100 to change the target blow-out temperature TAO to maintain the temperature inside the vehicle.

[0051] When the control device 100 determines that the heating load HL has increased (step S11), it calculates the required target heating capacity TGQ based on the increased heating load HL (step S12).

[0052] Based on the target heating capacity TGQ, the control device 100 calculates the input heat Qin required by the compressor 2 and the heat dissipation Qout in the indoor heat exchanger 21 that can maintain a balance with the input heat Qin. Furthermore, the control device 100 calculates the target speed TGNC of the compressor 2 required for the input heat Qin and the air volume AFO that can achieve the target blow-out temperature TAO while ensuring the heat dissipation Qout (step S13).

[0053] The control device 100 determines whether the current air volume Af is equal to the air volume AFO calculated in step S13, i.e., whether the current air volume Af is insufficient relative to the air volume AFO (step S14). If the current air volume Af is greater than or equal to the air volume AFO ("No" in step S14), the control device 100 performs control to make the speed of the compressor 2 reach the target speed TGNC calculated in step S13 (step S19).

[0054] On the other hand, if the current air volume Af is insufficient relative to the air volume AFO ("yes" in step S14), it is determined whether the current air volume Af is the maximum air volume Af_Max of the indoor heat exchanger 21, that is, whether the blower 23 is driven at the maximum speed (step S15).

[0055] If the current airflow Af is not the maximum airflow Af_Max of the indoor heat exchanger 21 ("No" in step S15), that is, if the blower 23 is driven at a speed lower than the maximum speed, the speed of the blower 23 is increased, thereby increasing the airflow supplied by the blower 23 to the indoor heat exchanger 21 (step S17). As a result, the airflow Af of the indoor heat exchanger 21 increases.

[0056] When the current airflow Af is the maximum airflow Af_Max of the indoor heat exchanger 21 ("Yes" in step S15), that is, when the blower 23 is already driven at maximum speed, the regulating damper 25 is driven to increase the proportion of outside air in the air drawn into the air conditioning unit 20 (step S16). The control device 100 controls the regulating damper 25 so that, for example, outside air accounts for 40% and inside air accounts for 60%.

[0057] In step S18, the control device 100 determines whether the heat dissipation Qout calculated in step S13 can be ensured by performing the above processing. If the heat dissipation Qout is insufficient ("No" in step S18), it returns to step S15 and repeats the above processing. On the other hand, if the heat dissipation Qout can be ensured ("Yes" in step S18), it performs control to make the speed of the compressor 2 reach the target speed TGNC calculated in step S13 (step S19).

[0058] Thus, in the vehicle air conditioning unit 1 of this embodiment, when the heating load HL increases in the hot air heating mode, the required heat dissipation Qout accompanying the increase in heating load HL can be ensured. That is, in the control device 100, when the airflow Af of the indoor heat exchanger 21 is insufficient, the airflow Af is increased by increasing the rotation speed of the blower 23, thereby increasing the heat dissipation Qout. On the other hand, if the airflow Af cannot be increased even when the blower 23 is driven at its maximum speed, the proportion of outside air is increased by driving the regulating damper 25, thereby lowering the temperature of the air passing through the indoor heat exchanger 21 and increasing the heat dissipation Qout.

[0059] This ensures the required input heat (Qin) as the heating load (HL) increases, as well as the heat dissipation (Qout) used to maintain a balance with the input heat (Qin). Therefore, the hot gas heating mode can be stably maintained, and the range of the compressor 2's target speed (TGNC) can be expanded, achieving the desired blow-out temperature and improving passenger comfort.

[0060] (Modified example) In the above example, the handling of the situation where the control device 100 determines that the heating load HL has increased is explained. However, for example, if the increase in the heating load HL is predicted, the above handling can be performed in advance to improve the comfort of the occupants.

[0061] The control device 100 obtains a predetermined driving route from the ECU controlling the navigation system and other ECUs that manage and control information such as weather information via the vehicle network L, and also obtains external environmental information along the driving route. In addition, the external environmental information includes environmental information such as tunnels along the driving route, and external air conditions such as external air temperature and external air humidity obtained based on the weather information of the driving route.

[0062] Furthermore, when the control device 100 predicts an increase in the heating load HL based on the acquired external environmental information, it performs... Figure 5 The processes in steps S12 to S19 allow for control of the vehicle air conditioning unit 1 before changes in the heating load HL occur, thus improving passenger comfort. Furthermore, by gradually or in stages controlling the speed of the blower 23 to ensure heat dissipation Qout, driving the damper 25, and controlling the speed of the compressor 2 during these processes, passenger comfort can be further improved.

[0063] As described above, according to this embodiment, by ensuring the required heat dissipation accompanying the increase in heating load, the hot air heating mode is stably maintained and the desired blow-out temperature is achieved, thereby improving the comfort of the occupants.

[0064] 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, and even design changes that do not depart from the spirit of the present invention are included in the present invention. Explanation of reference numerals in the attached figures:

[0065] 1: Vehicle air conditioning unit; 2: Compressor; 10: Refrigerant circuit; 10V: Hot gas bypass; 11: External heat exchanger; 12, 13: Flow path switching valve; 14, 15: Check valve; 16: Receiver; 20: Air conditioning unit; 21, 22: Indoor heat exchanger; 23: Blower; 24, 25: Regulating damper; 25A, 25B: Air inlet; 30: Heat medium circuit; 31: Circulation pump; 33: Temperature-regulated heat exchanger; 34: Refrigerant heat medium heat exchanger; 34A, 34B: Flow path; 40: Sensor unit; 41: External air sensor; 42: Compressor current sensor; 43, 43A, 43B: Refrigerant temperature sensor; 44, 44A, 44B: Refrigerant pressure sensor; 45: Occupant sensor; 46: Supply air temperature sensor; 47: Internal air sensor; 60: Input signal; 100: Control device.

Claims

1. An air conditioning unit for a vehicle, wherein, have: A refrigerant circuit includes: a compressor; an indoor heat exchange section; an external heat exchange section; and a hot gas bypass that depressurizes at least a portion of the refrigerant compressed by the compressor and returns it to the compressor without passing through the indoor heat exchange section and the external heat exchange section; The air conditioning unit, having an indoor heat exchange section internally, includes: a regulating damper for adjusting the ratio of indoor to outdoor air introduced into the unit; and a blower for supplying the introduced air; and The control device controls the refrigerant circuit and the air conditioning unit, and is capable of executing a hot gas heating mode. In this mode, a portion of the refrigerant compressed by the compressor flows in the hot gas bypass and returns to the compressor, while the remaining refrigerant dissipates heat in the indoor heat exchange section. During the execution of the hot gas heating mode, if the heating load is determined to have increased, the control device will control the compressor to expand the range of its target speed increase.

2. An air conditioning unit for a vehicle, wherein, have: A refrigerant circuit includes: a compressor; an indoor heat exchange section; an external heat exchange section; and a hot gas bypass that depressurizes at least a portion of the refrigerant compressed by the compressor and returns it to the compressor without passing through the indoor heat exchange section and the external heat exchange section; The air conditioning unit, having an indoor heat exchange section internally, includes: a regulating damper for adjusting the ratio of indoor to outdoor air introduced into the unit; and a blower for supplying the introduced air; and The control device controls the refrigerant circuit and the air conditioning unit, and is capable of executing a hot gas heating mode. In this mode, a portion of the refrigerant compressed by the compressor flows in the hot gas bypass and returns to the compressor, while the remaining refrigerant dissipates heat in the indoor heat exchange section. During the execution of the hot gas heating mode, the control device acquires external environmental information representing the external environment along a predetermined travel route. If an increase in heating load is predicted based on the external environmental information, the control device performs control to expand the range of increase in the target speed of the compressor.

3. The vehicle air conditioning unit according to claim 1 or 2, wherein, The control device controls the process to increase the heat dissipation of the indoor heat exchange section in accordance with the target speed of the compressor based on the increase in heating load, thereby expanding the range of increase.

4. The vehicle air conditioning unit according to claim 3, wherein, The control device is, This increases the air volume supplied by the blower to the indoor heat exchange section. When the air volume supplied by the blower is at its upper limit, the regulating damper is controlled to increase the proportion of outside air introduced into the air conditioning unit.

Images