Air conditioner for vehicle

Abstract

To execute control (control of rotating speed of compressor) of a refrigerant circuit capable of increasing efficiency of consumption energy of a compressor, when a hot gas heating operation mode is continuously operated.SOLUTION: An air conditioner for a vehicle includes a refrigerant circuit for decompressing a refrigerant discharged from a compressor and returning the decompressed refrigerant to the compressor, an in-cabin air conditioner for heating air blown into a cabin by an indoor heat exchange part of the refrigerant circuit, and a control device for controlling the refrigerant circuit and the in-cabin air conditioner on the basis of input information, wherein the refrigerant circuit includes a refrigerant flow channel which includes a hot gas bypass for decompressing a part of the refrigerant compressed by the compressor to a suction side of the compressor without through the indoor heat exchange part and flowing the decompressed refrigerant to the suction side of the compressor, and being capable of executing a hot gas heating operation mode, and the control device performs control of setting a target pressure of the refrigerant circuit to be variable, within a range that a heating request can be kept, in consideration of necessary capability required by the set heating request and vehicle request, in the hot gas heating operation mode of flowing a part of the refrigerant compressed by the compressor in the indoor heat exchange part and flowing the remaining refrigerant in the hot gas bypass.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] Air conditioners for electric vehicles (EVs) that do not have a combustion-based heat source such as an engine, or for vehicles that have a low heat output from a combustion-based heat source, generally use air conditioners that use a heat pump as a heat source. In normal heating operation, this air conditioner absorbs heat from outside air in an exterior heat exchanger that functions as a heat absorber, and heats the air to be blown into the vehicle cabin in a heat exchanger of the vehicle interior air conditioner that functions as a heat radiator. For this reason, in normal heating operation, when the outside air temperature becomes extremely low, it becomes difficult to absorb heat from the outside air, and the heating capacity decreases.

[0003] In contrast, the hot gas heating operation mode executes a cycle in which the high-temperature, high-pressure refrigerant discharged from the compressor of the heat pump flows through the heat exchange section of the vehicle interior air conditioner, and then decompresses and is drawn into the compressor without passing through the exterior heat exchange section, enabling heating operation in an extremely low-temperature outdoor environment where it is difficult to absorb heat in the exterior heat exchange section. This hot gas heating operation mode provides a bypass refrigerant flow path (hot gas bypass) in the refrigerant circuit that decompresses and returns a portion of the high-temperature, high-pressure refrigerant discharged from the compressor to the compressor without passing through the heat exchanger of the vehicle interior air conditioner, and allows a portion of the refrigerant compressed by the compressor to flow through the heat exchange section of the vehicle interior air conditioner and the remainder to flow through the hot gas bypass, making it possible to adjust the amount of heat input and release during operation (see Patent Document 1 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-46604 A Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, in hot gas heating operation mode, in order to perform continuous operation in response to various requests, the compressor of the refrigerant circuit is operated at a set speed close to its capacity limit so that the energy consumed by the compressor (heat input) exceeds the heat dissipation associated with the various requests. However, if the hot gas heating operation mode continues for a long period of time, the remaining power in the battery is reduced due to the energy consumed by the compressor, which causes a problem of shortening the driving range of the electric vehicle.

[0006] The present invention has been proposed in view of the above circumstances. That is, an object of the present invention is to execute control of the refrigerant circuit (control of the compressor speed) that can efficiently increase the energy consumption of the compressor when the hot gas heating operation mode is continuously operated. [Means for solving the problem]

[0007] In order to solve such problems, the present invention has the following configuration. a hot gas bypass that reduces the pressure of a portion of the refrigerant compressed by the compressor and flows it to the suction side of the compressor without passing through the indoor heat exchanger; and a control device that controls the refrigerant circuit and the vehicle interior air conditioner based on input information. The vehicular air conditioner includes a refrigerant circuit that reduces the pressure of a refrigerant discharged from a compressor and returns it to the compressor; Effect of the Invention

[0008] In a vehicle air conditioner having such characteristics, when the hot gas heating operation mode is continuously operated, it is possible to execute control of the refrigerant circuit (control of the compressor rotation speed) that can efficiently improve the energy consumption of the compressor. [Brief description of the drawings]

[0009] [Figure 1] 1 is an explanatory diagram showing an example of the configuration of a vehicle air conditioning device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is an explanatory diagram showing a control device of a vehicle air conditioner. [Diagram 3] FIG. 2 is an explanatory diagram showing the hardware configuration of a control device for a vehicle air conditioner mounted on an electric vehicle (EV). [Figure 4] FIG. 4 is an explanatory diagram showing a refrigerant circuit operation in a hot gas heating operation mode in the vehicle air conditioning system according to the embodiment of the present invention. [Diagram 5] FIG. 4 is a flow chart showing pre-processing for a mode selection process performed by the control device. [Figure 6] FIG. 4 is a flow chart showing a mode selection process performed by the control device. [Figure 7] FIG. 13 is a block diagram of a control device that performs variable PSO control after transition to a second selection mode. [Figure 8] FIG. 4 is an explanatory diagram showing an example of a data map for obtaining a range of a target value PCO of a high-pressure side refrigerant pressure from a target blow-off temperature TAO. [Figure 9] FIG. 4 is an explanatory diagram showing a method for determining a target operating state. [Figure 10] FIG. 13 is an explanatory diagram showing the relationship between PCO and PSO (inversely proportional linear relationship) when the target blowing temperature is constant. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different drawings indicate parts having the same function, and duplicated descriptions in each drawing will be omitted as appropriate.

[0011] [Configuration of refrigerant circuit, etc. in vehicle air conditioning system] 1 shows a configuration example of a vehicle air conditioner 1 according to an embodiment of the present invention. The configuration example shown here is just one example, and the present invention is not particularly limited to a specific configuration.

[0012] The vehicle air conditioner 1 includes a refrigerant circuit 10 and a vehicle interior air conditioner 20. The refrigerant circuit 10 has a refrigerant flow path that reduces the pressure of the refrigerant discharged from the compressor 2 and returns it to the compressor 2. The compressor 2, indoor heat exchangers 21 and 22 provided inside the vehicle interior air conditioner 20, and an outdoor heat exchanger 11 provided outside the vehicle interior are arranged along the refrigerant flow path. The indoor heat exchangers 21 and 22 are provided for heat exchange between the air flowing inside the vehicle interior air conditioner 20 and the refrigerant, and the outdoor heat exchanger 11 is provided for heat exchange between the outside air and the refrigerant outside the vehicle interior. For example, the indoor heat exchanger 21 is for heating the air, and the indoor heat exchanger 22 is for cooling the air. A refrigerant pressure sensor 44B that detects an outlet refrigerant pressure (high-pressure side refrigerant pressure) Pci from the indoor heat exchanger 21 is provided downstream of the indoor heat exchanger 21 in the refrigerant flow path.

[0013] The compressor 2 compresses the refrigerant and circulates it through the refrigerant circuit 10. The refrigerant compressed by the compressor 2 is decompressed to a required pressure by selectively passing 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 are, for example, expansion valves, in an appropriately selected refrigerant flow path. The refrigerant circuit 10 is provided with flow path switching valves 12 and 13 for switching the refrigerant flow path, and check valves 14 and 15 for restricting the flow direction of the refrigerant. An accumulator 16 is provided upstream of the compressor 2 in the refrigerant circuit 10 to recover liquid refrigerant and separate the refrigerant into gas and liquid. A refrigerant pressure sensor 44A is provided between the accumulator 16 and the compressor 2 to detect a suction refrigerant pressure (low-pressure side refrigerant pressure) Ps sucked into the compressor 2.

[0014] As described above, the vehicle interior air conditioner 20 includes the interior heat exchangers 21, 22, and air introduced from the inside or outside of the vehicle by the blower 23 passes through the interior heat exchangers 21, 22 to be temperature-adjusted and then blown into the vehicle. The vehicle interior air conditioner 20 is provided with an air damper 24. When the air damper 24 shown in Fig. 1 is fully open, the air introduced by the blower 23 passes through both the interior heat exchangers 21, 22 and is blown into the vehicle.

[0015] When the air damper 24 is fully closed, it blocks the inlet side of the indoor heat exchanger 21, and the air introduced by the blower 23 passes only through the indoor heat exchanger 22 before being blown into the room. Another air damper 25 provided in the vehicle interior air conditioner 20 switches the air introduced into the blower 23 between the indoor and outdoor air. The air damper 25 can selectively close an air inlet 25A connected to the outside of the room and an air inlet 25B connected to the inside of the room to introduce air from either one of them. Also, by placing the air damper 25 in an intermediate position, it is possible to introduce air from both the air inlet 25A and the air inlet 25B.

[0016] Although the above-mentioned examples of the outdoor heat exchange section 11 and the indoor heat exchange sections 21 and 22 have been described in which the refrigerant and the air directly exchange heat, the refrigerant and the air may indirectly exchange heat via a heat medium that has exchanged heat with the refrigerant. That is, the refrigerant may absorb heat from the air via the heat medium, or the refrigerant may dissipate heat to the air via the heat medium.

[0017] As shown in Fig. 1, the vehicle air conditioner 1 includes a heat medium circuit 30 for adjusting the temperature of an in-vehicle device. The heat medium circuit 30 circulates the heat medium using a circulation pump 31, heats the heat medium using a heater (ECH: Electric Coolant Heater) 32, and recovers waste heat from an in-vehicle device (temperature adjustment target) such as a battery using a temperature adjustment target heat exchanger 33. The refrigerant circuit 10 and the heat medium circuit 30 are provided with a refrigerant-heat medium heat exchanger 34 that exchanges heat between the refrigerant and the heat medium in a flow path 34A through which the refrigerant flows and a flow path 34B through which the heat medium flows, as a heat exchanger for adjusting the temperature of the in-vehicle device. Such a heat medium circuit 30 is provided as necessary.

[0018] [Control device] The vehicle air conditioner 1 includes a control device (air conditioner ECU) 100 shown in Fig. 2. The control device 100 controls the refrigerant circuit 10 and the vehicle interior air conditioner 20, as described above, based on various input information J including user setting information and information from the vehicle, and detection signals from the sensor unit 40, and also controls the heat medium circuit 30 as necessary. The control device 100 is also connected to a database DB used when executing a control mode, which will be described later. Note that this database DB does not need to exist inside the vehicle air conditioner 1, and it is sufficient that the database DB can be connected to an external database DB using the communication function of the vehicle.

[0019] The sensor section 40, which inputs detection signals to the control device 100, includes, for example, an outside air sensor 41 for detecting outside air conditions such as outside air temperature and outside 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, and a blower temperature sensor 45 for detecting the blower temperature of the vehicle interior air conditioning unit 20.

[0020] In particular, the refrigerant pressure sensor 44 includes a refrigerant pressure sensor 44A that detects the suction refrigerant pressure (low-pressure side refrigerant pressure) Ps sucked into the compressor 2, and a refrigerant pressure sensor 44B that detects the outlet refrigerant pressure (high-pressure side refrigerant pressure) Pci of the indoor heat exchange section 21 (see FIG. 1). These sensors are merely examples, and the sensor section 40 is provided with various sensors that detect information required when the control device 100 performs various controls.

[0021] The control targets of the control device 100 are the compressor 2, the first pressure reduction section V1, the second pressure reduction section V2, the third pressure reduction section V3, the fourth pressure reduction section V4, and the flow path switching valves 12 and 13 in the refrigerant circuit 10, the blower 23, the air dampers 24 and 25 in the vehicle interior air conditioner 20, and the circulation pump 31 in the heat medium circuit 30. The vehicle air conditioner 1 can be switched by the control device 100 between an outside air heat absorption heating operation mode in which outside air is absorbed by the outside heat exchange section 11, and a hot gas heating operation mode in which the high-temperature refrigerant compressed by the compressor 2 is dissipated by the inside heat exchange section 21 without the outside air absorbing heat in the outside heat exchange section 11 to heat the vehicle interior.

[0022] [Configuration of control device in electric vehicle (EV)] 3, the control device (air conditioning ECU) 100 provided in the vehicle air conditioner 1 is configured as one ECU connected to various ECUs (Electronic Control Units) that control the electric vehicle (EV) via an in-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 input / output I / F (Interface) 104, an in-vehicle communication I / F (Interface) 105, and the like, and each piece of hardware is connected to each other via a bus 106.

[0023] The CPU 101 executes various programs stored in the ROM 102 to control the control device 100. The ROM 102 is a non-volatile memory. For example, the ROM 102 stores programs executed by the CPU 101, data necessary for the CPU 101 to execute the programs, etc. The RAM 103 is a main storage device such as a DRAM (Dynamic Random Access Memory) or an SRAM (Static Random Access Memory).

[0024] For example, the RAM 103 functions as a working area used by the CPU 101 when executing a program. The input / output I / F 104 is connected to various sensors and monitors installed in the EV, and inputs data to the CPU 101 and outputs data processed by the CPU 101. The in-vehicle communication I / F 105 is connected to an in-vehicle network L to control data transmission and reception with other ECUs set in the EV.

[0025] The control device 100 controls the above-mentioned vehicle air conditioner 1 by a program executed by the CPU 101 when data related to surrounding environmental information or data related to the driving status of the EV is input via the input / output I / F 104 or the in-vehicle communication I / F 105.

[0026] The EV is equipped with a battery B. The battery B is charged by connecting a charger plug PS to a battery plug BP, and power is supplied to the vehicle air conditioner 1 via the battery B. The state in which the plug PS is connected to the battery plug BP is transmitted to the control device 100 via the in-vehicle network L as a charger connection signal.

[0027] [Outdoor air heat absorption heating operation mode] In the outdoor air heat absorption heating operation mode, the second pressure reduction section V2, the third pressure reduction section V3, the fourth pressure reduction section V4, and the flow path switching valve 12 are fully closed in the refrigerant circuit 10 shown in Fig. 1. On the other hand, the flow path switching valve 13 is open, and the first pressure reduction section V1 is open.

[0028] In the outside air heat absorption heating operation mode, the high-temperature, high-pressure refrigerant discharged from the compressor 2 passes through the indoor heat exchanger 21 in the vehicle interior air conditioner 20 and is depressurized in the first depressurization section V1, and the low-pressure refrigerant passes through the outdoor heat exchanger 11 and is returned to the compressor 2 via the flow path switching valve 13, the check valve 14, and the accumulator 16. At this time, the high-pressure refrigerant discharged from the compressor 2 condenses and releases heat in the indoor heat exchanger 21, is depressurized in the first depressurization section V1 to become a low-pressure refrigerant, absorbs heat and evaporates in the outdoor heat exchanger 11, and returns to the compressor 2. In the vehicle interior air conditioner 20, the air introduced by the blower 23 is heated by the heat released in the indoor heat exchanger 21 and is blown into the vehicle interior.

[0029] [Refrigerant circuit operation in hot gas heating operation mode] In the hot gas heating operation mode, the refrigerant is not allowed to absorb heat in the exterior heat exchange section 11, and some or all of the refrigerant compressed by the compressor 2 is caused to dissipate heat in the interior heat exchange section 21 to heat the vehicle cabin. The operation of the refrigerant circuit 10 in the hot gas heating operation mode will be described with reference to Fig. 4. In the illustrated refrigerant circuit 10, thick black lines indicate refrigerant flow paths through which high-pressure refrigerant flows, and hollow lines indicate refrigerant flow paths through which decompressed refrigerant flows. Furthermore, the dashed lines in the refrigerant circuit 10 indicate refrigerant flow paths through which refrigerant does not flow, and the dashed lines in the heat medium circuit 30 indicate that the flow of the heat medium has stopped.

[0030] 4, part of the high-temperature, high-pressure refrigerant discharged from the compressor 2 passes through the indoor heat exchange section 21 and the flow path switching valve 12, is depressurized in the third pressure reduction section V3 to become a low-pressure refrigerant, passes through the refrigerant heat medium heat exchange section 34, is separated into gas and liquid in the accumulator 16, and returns to the compressor 2. At this time, the refrigerant circuit 10 does not allow the refrigerant to flow to the outdoor heat exchange section 11 by fully closing the first pressure reduction section V1. Also, the fourth pressure reduction section V4 is fully closed to prevent the refrigerant from flowing to the indoor heat exchange section 22.

[0031] The refrigerant circuit 10 has a hot gas bypass 10V that reduces the pressure of 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 exchange unit 21 and the outdoor heat exchange unit 11, and is provided with a refrigerant flow path capable of executing a hot gas heating operation mode. In the hot gas bypass 10V, a portion of the high-temperature, high-pressure refrigerant is branched off at a branch point P1 immediately downstream of the compressor 2, reduced in pressure at a second pressure reduction unit V2, and merged with the low-pressure refrigerant reduced in pressure at a third pressure reduction unit V3 at a junction point P2 immediately upstream of the accumulator 16.

[0032] By providing such a hot gas bypass 10V, in the hot gas heating operation mode, the liquid refrigerant condensed by heat radiation in the indoor heat exchanger 21 is mixed with the gas refrigerant that has passed through the hot gas bypass 10V to produce a gas-rich refrigerant, which is then returned to the compressor 2. In addition, by increasing the refrigerant flow rate flowing through the hot gas bypass 10V, the amount of heat radiation in the indoor heat exchanger 21 can be suppressed, and by adjusting the refrigerant flow rate flowing through the hot gas bypass 10V by opening and closing the second pressure reduction section V2, the balance between the amount of heat radiation from the refrigerant circuit 10 and the amount of heat input to the compressor 2 can be maintained. In other words, the second pressure reduction section V2 functions as a flow rate adjustment section that adjusts the flow rate of the refrigerant flowing through the hot gas bypass 10V.

[0033] In the hot gas heating operation mode, the refrigerant flow in the flow path passing through the indoor heat exchanger 21 is decompressed in the third decompression section V3, so that the refrigerant upstream of that becomes high pressure refrigerant and the refrigerant downstream of that becomes low pressure refrigerant. At this time, it is important in order to maintain the heating capacity that heat exchange is not performed in the refrigerant-heat medium heat exchanger 34 in the low pressure side flow path. In the vehicle interior air conditioner 20, air introduced by the blower 23 is heated by heat radiation in the indoor heat exchanger 21 and is blown into the vehicle interior.

[0034] [Hot gas heating operation mode control] <Mode selection process> In the hot gas heating operation mode, control is performed to select between a first selection mode (fixed target pressure mode) and a second selection mode (variable target pressure mode) according to the operating conditions of the vehicle air conditioner 1, a heating request set by the user, a request from the vehicle, etc. The first selection mode (fixed target pressure mode) here is a heating performance priority mode for maximizing heating performance, in which the rotation speed of the compressor 2 of the refrigerant circuit 10 is continuously driven at the maximum rotation speed within the request, the target pressure of the refrigerant circuit 10 (for example, the target value PSO of the low-pressure side refrigerant pressure) is set to a fixed value, and the actually measured pressure is controlled to approach the target pressure.

[0035] In contrast, the second selection mode (variable target pressure mode) is a control mode that prioritizes requirements such as improving the coefficient of performance (COP), and does not limit the rotation speed of the compressor 2 of the refrigerant circuit 10 to the maximum rotation speed, but variably sets the target pressure of the refrigerant circuit 10 (for example, the target value PSO of the low-pressure side refrigerant pressure) according to the requirement, and controls so that the measured pressure approaches the target pressure. In this second selection mode, control is performed to make the energy consumption of the refrigerant circuit 10 more efficient, on the premise that the heating requirement set by the user (set temperature and set air volume) is maintained while ensuring that the hot gas heating operation mode is established (the amount of heat input is greater than or equal to the amount of heat released).

[0036] In order to select the first selection mode or the second selection mode, the process shown in FIG. 5 is executed. Here, when the process is started ("START"), the first pre-processing S1, the second pre-processing S2, and the third pre-processing S3 are performed to calculate the required capacity TGQ required by the heating request set by the user and the request from the vehicle (vehicle request), and the rotation speed limit of the compressor 2 due to the request from the vehicle is grasped, and the mode selection process S4 is performed taking into account the required capacity TGQ that has been calculated. The series of process flows from start ("START") to end ("END") here are repeated at a predetermined time interval after the hot gas heating operation mode is started. The required capacity TGQ calculated here is the energy per unit time [J / s] required to satisfy each of the above-mentioned requests.

[0037] In FIG. 5, the first pre-processing S1 obtains a target heating capacity based on, for example, a heating request (set temperature and set air volume) set by a user. The second pre-processing S2 obtains a capacity required for temperature control of an in-vehicle device (temperature control target) based on, for example, input information from a vehicle. Specifically, the target temperature control capacity is estimated from the target temperature of the temperature control target. At this time, the heat medium circuit 30 shown in FIG. 4 is put into operation according to a request from the vehicle that performs temperature control of the in-vehicle device. The third pre-processing S3, for example, determines the vehicle's operation mode, such as a COP improvement operation mode (so-called eco-operation mode) or a quiet operation mode (operation mode that suppresses noise), based on information from the vehicle, and obtains a request to limit the rotation speed of the compressor 2 associated with the operation mode.

[0038] When the mode selection process S4 starts ("START"), a judgment process S10 for selecting a mode is performed as shown in Fig. 6. In the judgment process S10, a first judgment process S10A judges whether or not the hot gas heating operation mode has just been started, and a second judgment process S10B judges whether or not there is an achievement margin for the required capacity TGQ obtained in the first pre-processing S1 and the second pre-processing S2 described above.

[0039] Here, the first judgment process S10A judges whether the time t measured from the start of activation of the hot gas heating operation mode exceeds a set time t0, for example, and judges that it is just after activation of the hot gas heating operation mode if it does not exceed the set time t0 (S10A: Y), and judges that it is not just after activation of the hot gas heating operation mode if it exceeds the set time t0 (S10A: N). The set time t0 here can be set to a range as necessary.

[0040] The second judgment process S10B judges that there is a surplus (S10B: Y) if a state continues that satisfies the condition that the difference between the required capacity TGQ and the actual heating capacity Qhp is small or the required capacity TGQ itself is small in the first place (TGQ-Qhp<α or TGQ<β; α and β are different set values), and judges that there is no surplus (S10B: N) if this condition is not met.

[0041] In the judgment process S10, if the first judgment process S10A judges that the hot gas heating operation mode has just been started (S10A:Y), the transition process S11 to the first selection mode is executed, and even if the first judgment process S10A judges that the hot gas heating operation mode has not just been started (S10A:N), if the second judgment process S10B judges that there is no margin for error (S10B:N), the transition process S11 to the first selection mode is executed.

[0042] Then, in the judgment process S10, if the first judgment process S10A judges that it is not immediately after starting the hot gas heating operation mode (S10A: N), and further, if the second judgment process S10B judges that there is a margin (S10B: Y), then the transition process S20 to the second selection mode is executed.

[0043] After the process S11 for transition to the first selection mode, the rotation speed limit request of the compressor 2 acquired in the third pre-processing S3 described above is confirmed, and the compressor 2 is driven at the maximum rotation speed taking into consideration the rotation speed limit request while performing fixed PSO control S12, which will be described later. In addition, after the process S20 for transition to the second selection mode, variable PSO control S21, which will be described later, is performed.

[0044] <Fixed PSO control after transition to first selection mode> In the fixed PSO control (S12) after transition to the first selection mode, the control device 100 controls the refrigerant circuit 10 so that the high-pressure side refrigerant pressure of the refrigerant circuit 10 (such as the outlet refrigerant pressure Pci of the indoor heat exchanger 21 and the discharge refrigerant pressure of the compressor 2) becomes the target value PCO while continuing to drive the compressor 2 at the maximum rotation speed considering the above-mentioned rotation speed limit request. At this time, the second pressure reducing section V2 provided in the hot gas bypass 10V is controlled so that the actual measured value Ps of the low-pressure side refrigerant pressure of the refrigerant circuit 10 (such as the suction refrigerant pressure Ps of the compressor 2) approaches the target value PSO, which is a fixed value, and the air volume of the blower 23 is controlled so that the actual heating capacity Qhp of the vehicle air conditioner 1 becomes the required capacity TGQ.

[0045] <Variable PSO control after transition to second selection mode> In the variable PSO control (S21) after transition to the second selection mode, a target operating state of the refrigerant circuit 10 determined according to the heating request set by the user and the vehicle request is determined, and control is performed so that the actual measured value approaches the target operating state. The target operating state can be specified by the target pressure of the refrigerant circuit 10 (the target value PCO of the high-pressure side refrigerant pressure and the target value PSO of the low-pressure side refrigerant pressure), and is represented as (PCO, PSO) below.

[0046] To determine the target operating states (PCO, PSO) of the refrigerant circuit 10, a data map stored in a database DB connected to the control device 100 can be used. When the user-set heating request (set temperature and set air volume) and information related to vehicle requests are input as input information J, the control device 100 consults the operating state map stored in the database DB for this information and determines a target range of operating states that meets the requests. Then, if the vehicle requests include a request for improved COP or quiet operation, the control device 100 determines, within the determined target range of operating states, an operating state that can keep the rotation speed of the compressor 2 to the lowest as the target operating state (PCO, PSO).

[0047] An example of the control logic for determining the target operating state is shown below, but the embodiment of the present invention is not particularly limited to this. In the following example, variable PSO control is described on the premise that the blowing temperature is fixed based on the heating request set by the user.

[0048] 7, when a user-set heating request is input as input information J, the control device 100 calculates a target blowing temperature TAO based on the set temperature. Then, the control device 100 checks the calculated target blowing temperature TAO against a TAO / PCO map 110 acquired from a database DB to determine the range of a target value PCO of the high-pressure side refrigerant pressure.

[0049] The TAO / PCO map 110 used here may be a data map as shown in Fig. 8. This data map is a map of the relationship between the measured value Pci of the high-pressure side refrigerant pressure and the measured value of the blowing temperature of the compressor 2. It should be noted here that the relationship between the measured value Pci and the blowing temperature is such that the measured value Pci that can achieve the same blowing temperature is not a fixed value but a region, as shown by region M in the figure. The example shown in the figure indicates that the measured value Pci that can achieve a blowing temperature of 55°C is in the range from 1.7 MPa to 1.9 MPa.

[0050] 8 is used as the TAO / PCO map, the target value PCO of the high-pressure refrigerant pressure for keeping the target blowing temperature TAO constant can be specified within a range represented by upper and lower limits for the input target blowing temperature TAO. For example, when the target blowing temperature TAO is fixed at 55°C, the corresponding target value PCO can be determined to be in the range of 1.7 MPa to 1.9 MPa.

[0051] Then, the control device 100 further narrows down the range of the target value PCO determined by the TAO / PCO map in a narrowing-down processing unit 111 to specify the target operating state (PCO, PSO). In the narrowing-down processing unit 111, a required capacity TGQ taking into account the vehicle requirements and a rotation speed limit requirement NC of the compressor 2 based on the vehicle requirements are used.

[0052] As shown in Fig. 9, the narrowing processing unit 111 determines a further narrowed PCO range (for example, from A1 to B1 in the figure) for a PCO range (from A0 to B0 in the figure) where the target air outlet temperature TAO is constant, taking into consideration the required capacity TGQ and the rotation speed limit requirement NC. In Fig. 9, assuming that control is performed to keep the target air outlet temperature TAO constant, when the target value PCO is increased, the rotation speed limit requirement NC needs to be set to a lower rotation speed, and the required capacity TGQ also needs to be set to a lower value. On the other hand, when the target value PCO is increased, the rotation speed limit requirement NC and the required capacity TGQ decrease, and the COP increases.

[0053] In FIG. 9, when the upper limit of the rotation speed limit requirement NC is required within the range (from A0 to B0) of the target value PCO at which the target blowing temperature TAO is constant, the value (A1) of the target value PCO corresponding to the upper limit becomes the lower limit of the target value PCO range. Further, when the lower limit of the required capacity TGQ is required within the range (from A0 to B0) of the target value PCO at which the target blowing temperature TAO is constant, the value (B1) of the target value PCO corresponding to the lower limit becomes the upper limit of the target value PCO range. And when there are requirements for COP improvement and / or quiet operation according to vehicle requirements, the rotation speed limit requirement NC will select the lowest rotation speed within the range. Therefore, in the illustrated example, the value of the target value PCO is specified as B1 to set the target operating state.

[0054] Under the condition that the target blowing temperature TAO is constant, the relationship between the target value PCO and the target value PSO is an inverse proportional linear relationship as shown in FIG. 10 (in the figure, a1 < a2 < a3, b1 < b2 < b3). Using this linear relationship, the specific value of the target value PSO corresponding to the specific value of the specified target PCO is obtained, and the target operating state (PCO, PSO) is determined by these combinations.

[0055] Thus, in the variable PSO control after the second selection mode transition, within the range where the user-set heating requirement can be maintained (for example, the target blowing temperature TAO is constant), considering the user-set heating requirement, the required capacity TGQ and the rotation speed limit requirement NC based on vehicle requirements, the target operating state (PCO, PSO) is determined, and control is performed such that the measured value approaches the target value of the determined target operating state. According to this, when there are requirements such as COP improvement and quiet operation as vehicle requirements, air conditioning control can be performed to satisfy the user-set heating requirement while suppressing the rotation speed of the compressor 2. Therefore, when continuously operating the hot gas heating operation mode, it is possible to suppress the shortening of the cruising range of the electric vehicle.

[0056] In the variable PSO control after transitioning to the second selection mode, a target operating state (PCO, PSO) is set that satisfies not only the heating request set by the user but also multiple vehicle requests. When the heating request or vehicle request set by the user is changed, the required capacity TGQ is calculated each time, and the rotation speed limit request NC is confirmed, and a new target operating state (PCO, PSO) is set.

[0057] According to such a vehicle air conditioner 1, when the hot gas heating operation mode is selected, immediately after the start, the first selection mode is entered as determined by the first determination process S10A described above, and the refrigerant circuit 10 is controlled to bring the actual measured pressure closer to a fixed target pressure (for example, the target value PSO of the low-pressure side refrigerant pressure) while rotating the compressor 2 at the maximum rotation speed. Then, when the hot gas heating operation mode continues for a predetermined time and the actual heating capacity Qhp improves to generate an achievement margin for the required capacity TGQ, the second determination process S10B determines that there is a margin, and the second selection mode is entered, and as described above, the variable PSO control is automatically entered, in which the target operating state (PCO, PSO) that satisfies the heating request and vehicle request set by the user is variably set each time. Furthermore, if the heating request or vehicle request set by the user is changed after the transition to the second selection mode, and the second determination process S10B determines that there is no achievement margin, the second selection mode is entered as well.

[0058] In this way, according to the vehicle air conditioner 1, when the hot gas heating operation mode is continued, the first selection mode is automatically switched to the second selection mode and vice versa, but since the heating request set by the user is maintained at that time, the user can continue the hot gas heating operation mode without losing comfort. Then, if the achievement margin condition in the second judgment process S10B is satisfied, the system automatically switches to efficient control of the refrigerant circuit 10 that satisfies various requests, so that an operation that avoids excessive energy consumption while ensuring the user's comfort can be performed.

[0059] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes design changes and the like that do not deviate from the gist of the present invention. [Explanation of symbols]

[0060] 1: vehicle air conditioner, 2: compressor, 10: refrigerant circuit, 10V: hot gas bypass, 11: outdoor heat exchanger, 12, 13: flow path switching valve, 14, 15: check valve, 16: accumulator, 20: vehicle interior air conditioning device, 21, 22: indoor heat exchange section, 23: blower, 24, 25: air damper, 25A, 25B: air inlet, 30: heat medium circuit, 31: circulation pump, 32: heater; 33: temperature control target heat exchanger; 34: refrigerant / heat medium heat exchanger; 34A, 34B: flow path, 40: sensor unit, 41: outside air sensor, 42: compressor current sensor, 43: refrigerant temperature sensor, 44, 44A, 44B: refrigerant pressure sensors, 45: Air temperature sensor, 100: Control device, J: Input information

Claims

1. An air conditioner for a vehicle including a refrigerant circuit that reduces the pressure of a refrigerant discharged from a compressor and returns the refrigerant to the compressor, an interior air conditioner that adjusts the temperature of air to be blown into a vehicle cabin by an interior heat exchanger of the refrigerant circuit, and a control device that controls the refrigerant circuit and the interior air conditioner based on input information, the refrigerant circuit includes a refrigerant flow path capable of executing a hot gas heating operation mode, the hot gas bypass being configured to reduce the pressure of a portion of the refrigerant compressed by the compressor and flow it to the suction side of the compressor without passing through the indoor heat exchanger; The control device includes: In the hot gas heating operation mode, a part of the refrigerant compressed by the compressor flows through the indoor heat exchange section and the remainder flows through the hot gas bypass. Taking into account the required capacity required by the set heating demand and vehicle demand, The vehicle air conditioner performs control to variably set a target pressure of the refrigerant circuit within a range in which the heating request can be maintained.

2. The control device includes: Determining the achievement margin for the required capacity, If there is a margin, the target pressure is variably set, 2. The vehicle air conditioner according to claim 1, wherein when there is no margin, the rotational speed of the compressor is set to a maximum rotational speed and the target pressure is set to a fixed value.

3. 2. The vehicle air conditioner according to claim 1, wherein the heating request is specified by a set temperature and a set air volume.

4. The control device includes: determining a target range of a high-pressure side refrigerant pressure that can maintain the set temperature; 4. The vehicle air conditioning system according to claim 3, wherein the target value of the high-pressure side refrigerant pressure is specified within the target range based on the vehicle requirement, and the target value of the low-pressure side refrigerant pressure is specified from the specified target value of the high-pressure side refrigerant pressure.

5. the refrigerant circuit includes a heat exchanger for adjusting the temperature of an in-vehicle device, The vehicle requirement includes:

2. The vehicle air conditioner according to claim 1, further comprising a temperature control request from the vehicle-mounted device and a limit request from the vehicle.

6. The restriction request is:

6. The vehicle air conditioner according to claim 5, wherein the request to limit the rotation speed of the compressor is associated with one or both of a quiet operation mode and a COP improvement operation mode of the vehicle.

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