Vehicle air conditioning device

Abstract

The purpose of the present invention is to ensure quick heating during hot-gas heating operation, and to suppress variations in the discharge temperature, thereby improving the comfort of a user. A vehicle air-conditioning device is provided with: a refrigerant circuit including a compressor, an indoor heat exchange unit, and an external heat exchange unit; and a control device for controlling the refrigerant circuit, the refrigerant circuit having: a hot gas bypass for reducing the pressure of at least a portion of the refrigerant compressed by the compressor and returning the refrigerant to the compressor without passing through the indoor heat exchange unit and the external heat exchange unit; in a hot-air heating mode in which a part of the refrigerant compressed by the compressor flows to the indoor heat exchange unit and the remainder flows to the hot-air bypass, the control device drives the compressor at a predetermined fixed rotational speed at the time of startup, and then adjusts the flow rate of the refrigerant flowing through the hot-air bypass. An FF / FB mode in which the rotational speed of the compressor is controlled by the FF control and the FB control is executed, and a predetermined initial value is set for an integral term of the FB control when switching to the FF / FB mode.

Description

TECHNICAL FIELD

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

[0002] In recent years, vehicles such as hybrid vehicles and electric vehicles that drive a traveling motor using electric power supplied from a battery mounted on the vehicle have been popularized. As a vehicle air-conditioner mounted on such a vehicle, a vehicle air-conditioner that uses a heat pump (refrigerant circuit) as a heat source is known.

[0003] A vehicle air-conditioner that uses a heat pump functions as a heat absorber using an external heat exchanger to obtain a heating heat source from outside air during heating operation. Therefore, if the outside air temperature becomes extremely low, it becomes difficult to absorb heat from the outside air, and the heating capacity can greatly decrease. In this regard, as heating that is effective in an extremely low temperature environment, heat is not absorbed from outside air or the like, but heat is generated by high-temperature and high-pressure refrigerant discharged from a compressor of a refrigerant circuit.

[0004] For example, in the vehicle air-conditioner of Patent Literature 1, during heat pump operation, refrigerant is circulated as follows to perform heat-generating operation. That is, in the heat pump, a part of high-temperature and high-pressure refrigerant discharged from the compressor is made to flow to a bypass flow passage and is depressurized to return to the compressor, and the remaining part is depressurized after heat-exchanging with air blown into the vehicle cabin in an indoor heat exchanger, and returns to the compressor without passing through the external heat exchanger.

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2023-46604

[0006] In the vehicle air-conditioner described above, the compressor is generally controlled in such a manner that the compressor is driven at a target rotational speed calculated in a predetermined period by feedforward control (hereinafter referred to as FF control) and feedback control (hereinafter referred to as FB control) from the start of heat-generating operation. In this case, for example, at the time of heat-generating operation start, time is required from a state in which the compressor is stopped to a state in which the compressor is driven at a maximum rotational speed, and therefore there is a possibility that the user's comfort can be impaired due to a lack of rapid warming performance.

[0007] In this regard, in order to ensure rapid warming performance, the compressor is driven at a high fixed rotational speed from the start of heat-generating operation, and if this state continues for a certain period of time or more, NVH (Noise Vibration Harshness) occurs, and the durability of the compressor decreases. In addition, if the compressor is driven at a fixed rotational speed, there is a problem that adjustment of the refrigerant pressure cannot be performed in the case where an interference is input.

[0008] Therefore, it can be considered that the compressor is driven at a fixed rotation speed at the start of the hot-gas heating operation, and then, for example, in the case where the outlet temperature of the indoor heat exchanger or the outlet refrigerant pressure reaches a target value, the FF control and the FB control are switched to control the compressor.

[0009] However, at the time of switching to the FF control and the FB control, the execution time of the FB control up to that point is almost none or short, and therefore the integral term of the FB control is small, and the calculated target rotation speed becomes a value smaller than the fixed rotation speed up to that point. Therefore, at the time of switching to the FF control and the FB control, the rotation speed of the compressor sometimes temporarily decreases, and therefore the blowout temperature fluctuates to impair the comfort of the user. SUMMARY The present application was completed in view of such circumstances, and aims to ensure rapid warm-up in the hot-gas heating operation, and to suppress fluctuation of the blowout temperature to improve the comfort of the user or the like.

[0010] The present application provides a vehicle air-conditioning device including: a refrigerant circuit including a compressor, an indoor heat exchanger, and an external heat exchanger; and a control device that controls the refrigerant circuit, wherein the refrigerant circuit has a hot-gas bypass that decompresses at least a portion of refrigerant compressed by the compressor and returns the refrigerant to the compressor without passing through the indoor heat exchanger and the external heat exchanger, and a flow rate adjustment portion that adjusts the flow rate of refrigerant flowing in the hot-gas bypass, the control device is capable of executing a hot-gas heating mode in which a portion of refrigerant compressed by the compressor flows to the indoor heat exchanger and a remaining portion flows to the hot-gas bypass, in the hot-gas heating mode, the control device, after executing a fixed mode in which the compressor is driven at a predetermined fixed rotation speed at the start of the hot-gas heating mode, executes an FF / FB mode in which the rotation speed of the compressor is controlled by feedforward control and feedback control, and sets a predetermined initial value to an integral term of the feedback control at the time of switching from the fixed mode to the FF / FB mode.

[0011] According to the present application, it is possible to ensure rapid warm-up in the hot-gas heating operation, and to suppress fluctuation of the blowout temperature to improve the comfort of the user. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is an explanatory diagram showing a system configuration example of a vehicle air-conditioning device of an embodiment of the present application. Figure 2 is an explanatory diagram showing a control device of a vehicle air-conditioning device of an embodiment of the present application. Figure 3 is a diagram showing the structure of a control device or the like in an electric vehicle (EV) of an embodiment of the present application. Figure 4is an explanatory view showing the operation of the refrigerant circuit at the time of the heat-absorption heating operation of the vehicle air-conditioning apparatus according to the embodiment of the present application. Figure 5 is an explanatory view showing the operation of the refrigerant circuit at the time of the hot-gas heating operation of the vehicle air-conditioning apparatus according to the embodiment of the present application. Figure 6 is a coordinate graph showing an example of the behavior of the outlet refrigerant pressure of the indoor heat exchanger, the rotation speed of the compressor, and the blow-out temperature at the time of the hot-gas heating operation according to the control method of the reference example. Figure 7 is a coordinate graph showing an example of the behavior of the outlet refrigerant pressure of the indoor heat exchanger, the rotation speed of the compressor, and the blow-out temperature at the time of the hot-gas heating operation according to the control method of the embodiment of the present application. DETAILED DESCRIPTION

[0013] Embodiments of the present application will be described below with reference to the accompanying drawings. In the following description, the same reference numerals in different drawings denote the same functional portions, and repetitive description will be appropriately omitted in the drawings. In addition, in the drawings, the black thick lines in the refrigerant circuit 10 represent refrigerant flow passages for high-pressure refrigerant, and the hollow lines represent refrigerant flow passages for low-pressure refrigerant. Further, the dotted lines in the refrigerant circuit 10 represent refrigerant flow passages in which no refrigerant flows.

[0014] [Structure of Refrigerant Circuit and the Like] Figure 1 is a structural example of the vehicle air-conditioning apparatus 1 according to the embodiment of the present application. The structural example shown here is an example, and is not particularly limited to a specific structure.

[0015] The vehicle air-conditioning apparatus 1 is provided with a refrigerant circuit 10 and an air-conditioning unit 20. The refrigerant circuit 10 includes a compressor 2, indoor heat exchangers 21, 22 provided inside the air-conditioning unit 20, and an outdoor heat exchanger 11 provided outside the vehicle cabin, which are provided along refrigerant flow passages. The indoor heat exchangers 21, 22 are provided in order to exchange heat between air flowing inside the air-conditioning unit 20 and refrigerant, and the outdoor heat exchanger 11 is provided in order to exchange heat between outside air and refrigerant outside the vehicle cabin. The indoor heat exchanger 21 is used for heating of air, and the indoor heat exchanger 22 is used for cooling of air. A refrigerant pressure sensor 44B is provided on the immediately downstream side of the indoor heat exchanger 21, and detects the outlet refrigerant pressure Pci (high-pressure-side refrigerant pressure) discharged from the indoor heat exchanger 21.

[0016] The compressor 2 compresses refrigerant and circulates it in the refrigerant circuit 10. The refrigerant compressed in the compressor 2 is reduced in pressure to a desired pressure in a refrigerant flow passage selected as appropriate, for example, by being reduced in pressure through the first pressure reducing portion VI, the second pressure reducing portion V2, the third pressure reducing portion V3, and the fourth pressure reducing portion V4 as expansion valves. The refrigerant circuit 10 is provided with flow passage switching valves 12, 13 for switching the refrigerant flow passage, and check valves 14, 15 for restricting the flow direction of the refrigerant. On the immediately upstream side of the compressor 2 in the refrigerant circuit 10, a receiver 16 is provided which recovers liquid refrigerant and performs gas-liquid separation of the refrigerant. Between the receiver 16 and the compressor 2, a refrigerant pressure sensor 44A is provided which detects the suction refrigerant pressure Ps (low-pressure-side refrigerant pressure) sucked into the compressor 2.

[0017] As described above, the air conditioning unit 20 is internally provided with the indoor heat exchangers 21, 22, and the air introduced from the indoor or outdoor by the air blower 23 passes through the indoor heat exchangers 21, 22 and is blown into the indoor. The air conditioning unit 20 is provided with a damper 24. The damper 24 is provided to switch the air passage between the indoor heat exchangers 21, 22 and the outdoor heat exchanger 11. Figure 1 When the damper 24 shown in the drawing is fully opened, the air introduced by the air blower 23 passes through both of the indoor heat exchangers 21, 22 and is blown into the indoor.

[0018] Further, when the damper 24 is fully closed, the suction side of the indoor heat exchanger 21 is blocked, and the air introduced by the air blower 23 passes through only the indoor heat exchanger 22 and is blown into the indoor. Another damper 25 provided to the air conditioning unit 20 switches the air introduced into the air blower 23 between the indoor and the outdoor. The damper 25 can selectively close the air introduction port 25A connected to the outdoor and the air introduction port 25B connected to the indoor and take in the air from one of them. Further, the air can be taken in from both of the air introduction port 25A and the air introduction port 25B by placing the damper 25 in an intermediate position or the like.

[0019] In addition, while an example in which the refrigerant and the air directly exchange heat in the aforementioned outdoor heat exchanger 11 and indoor heat exchangers 21, 22 is described, the refrigerant and the air can indirectly exchange heat by means of a heat medium which exchanges heat with the refrigerant. That is, the refrigerant can be caused to absorb the heat of the air by means of the heat medium or the heat of the refrigerant can be released to the air by means of the heat medium.

[0020] As Figure 1As shown, the vehicle air-conditioning device 1 is provided with a heat medium circuit 30. The heat medium circuit 30 circulates a heat medium by a circulation pump 31, and heats the heat medium by a heater (ECH: Electric Coolant Heater) 32 or recovers waste heat from a temperature adjustment target such as a battery by a temperature adjustment target heat exchanger 33. Further, the refrigerant circuit 10 and the heat medium circuit 30 are provided with a refrigerant-heat medium heat exchanger 34 that performs heat exchange between refrigerant flowing in a flow path 34A and heat medium flowing in a flow path 34B. The heat medium circuit 30 is provided as necessary.

[0021] [Control device] The vehicle air-conditioning device 1 is provided with Figure 2 the control device 100 shown. The control device 100 controls the aforementioned refrigerant circuit 10, air-conditioning unit 20, and heat medium circuit 30 based on various input signals (air-conditioning instruction signal, charger connection signal, etc.) and detection signals from the sensor section 40.

[0022] The sensor section 40 that inputs detection signals to the control device 100 is provided with, for example, an outside air sensor 41 that detects an outside air temperature, outside air humidity, and the like, a compressor current sensor 42 for detecting a consumption power (consumption energy) of the compressor 2, a refrigerant temperature sensor 43 and a refrigerant pressure sensor 44 that detect a state of refrigerant, a passenger sensor 45 that detects the presence or absence of a passenger in a vehicle cabin, and an air supply temperature sensor 46 that detects an air supply temperature of the air-conditioning unit 20.

[0023] In particular, the refrigerant pressure sensor 44 includes a refrigerant pressure sensor 44A that detects a suction refrigerant pressure Ps (low-pressure-side refrigerant pressure) that is suctioned into the compressor 2, and a refrigerant pressure sensor 44B that detects an outlet refrigerant pressure Pci (high-pressure-side refrigerant pressure) of the indoor heat exchanger 21 (see Figure 1 ). These sensors are an example, and various sensors that detect information necessary when the control device 100 performs various controls are provided as the sensor section 40.

[0024] The control objects of the control device 100 in the refrigerant circuit 10 include 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; in the air conditioning unit 20, include the blower 23, the dampers 24 and 25; and in the heat medium circuit 30, include the circulating pump 31. Furthermore, the control device 100 controls the vehicle air conditioning system 1 based on the processing results of the control device 100. The vehicle air conditioning system 1 can be switched by the control device 100 to perform: heat absorption heating operation, in which the refrigerant absorbs heat through the external heat exchanger 11; and hot gas heating operation, in which the refrigerant compressed by the compressor 2 dissipates heat in the interior heat exchanger 21, rather than through the external heat exchanger 11, to heat the vehicle interior.

[0025] [Structure of a control device in an electric vehicle (EV)] like Figure 3 As shown, the control device 100 included in the vehicle air conditioning system 1 is configured as an ECU (Electronic Control Unit), which is connected to various ECUs that control the electric vehicle (EV) via an in-vehicle network L. The control device 100 includes a CPU (Central Processing Unit) 101, ROM (Read Only Memory) 102, RAM (Random Access Memory) 103, input / output I / F (Interface) 104, and in-vehicle communication I / F (Interface) 105. These hardware components are interconnected via a bus 106.

[0026] CPU 101 controls control device 100 by executing various programs stored in ROM 102. ROM 102 is a nonvolatile memory. For example, ROM 102 stores programs executed by CPU 101 and data required for CPU 101 to execute the programs. RAM 103 is a main storage device such as DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory).

[0027] For example, RAM 103 functions as a workspace used by CPU 101 when executing programs. Input / output I / F 104 connects to various sensors and monitors installed in the EV, inputs data to CPU 101, and outputs data processed by CPU 101. In-vehicle communication I / F 105 connects to the in-vehicle network L to control data transmission and reception with other ECUs installed in the EV.

[0028] The control device 100 receives data on surrounding environmental information and data on the operating status of the EV via the input / output I / F 104 and the in-vehicle communication I / F 105 , thereby controlling the vehicle air conditioner 1 as described above through a program executed by the CPU 101 .

[0029] The EV is equipped with a battery B. 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 battery B. When the charger PS is connected to the battery plug BP, a charger connection signal is transmitted to the control device 100 via the in-vehicle network L.

[0030] [Endothermic heating operation] according to Figure 4 The operation of the refrigerant circuit 10 during heat absorption heating operation is described below. In the refrigerant circuit 10 during heat absorption 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 fully closed. Meanwhile, the flow path switching valve 13 is fully open, and the first pressure reducing section V1 is open.

[0031] During heat absorption 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 reduced in pressure in 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 accumulator 16, before returning to the compressor 2. At this point, the high-pressure refrigerant discharged from the compressor 2 condenses and dissipates heat in the indoor heat exchanger 21. It is then reduced in pressure by the first pressure reducing section V1 to become low-pressure refrigerant, which absorbs heat in the external heat exchanger 11, evaporates, and returns to the compressor 2. Furthermore, in the air conditioning unit 20, the air introduced by the blower 23 is heated by the heat dissipated in the indoor heat exchanger 21 and is then blown into the vehicle interior.

[0032] [Hot gas heating operation] At extremely low temperatures, the external heat exchanger 11 has difficulty absorbing heat, so hot gas is used for heating. In hot gas heating operation, the refrigerant compressed by the compressor 2 does not absorb heat in the external heat exchanger 11, but rather dissipates part or all of the heat through the indoor heat exchanger 21 to heat the vehicle interior.

[0033] according to Figure 5, the operation of the refrigerant circuit 10 at the time of the hot-gas heating operation will be described. In this operation, a part of the high-temperature and high-pressure refrigerant discharged from the compressor 2 passes through the indoor heat exchanger 21 and the flow passage switching valve 12, is depressurized in the third pressure-reducing portion V3 to become low-pressure refrigerant, and passes through the refrigerant heat medium heat exchanger 34, is separated into gas and liquid in the accumulator 16, and is returned to the compressor 2. At this time, in the refrigerant circuit 10, the first pressure-reducing portion VI is made to be fully closed, so that no refrigerant flows in the external heat exchanger 11. Further, the fourth pressure-reducing portion V4 is made to be fully closed, so that no refrigerant flows in the indoor heat exchanger 22.

[0034] The refrigerant circuit 10 has a hot-gas bypass 10V that depressurizes at least a part of the refrigerant compressed by the compressor 2 without passing through the indoor heat exchanger 21 and the external heat exchanger 11 and returns it to the compressor 2. In the hot-gas bypass 10V, a part of the high-temperature and high-pressure refrigerant is branched at a branching point Pl that is directly downstream of the compressor 2, is depressurized by the second pressure-reducing portion V2, and is merged with the low-pressure refrigerant depressurized by the third pressure-reducing portion V3 at a merging point P2 that is directly upstream of the accumulator 16.

[0035] By providing such a hot-gas bypass 10V, it is possible to mix the gas refrigerant that has passed through the hot-gas bypass 10V with the liquid refrigerant condensed due to heat release in the indoor heat exchanger 21 and return it to the compressor 2 as gas-rich refrigerant. Further, by increasing the refrigerant flow rate flowing in the hot-gas bypass 10V, it is possible to suppress the amount of heat release in the indoor heat exchanger 21, and by adjusting the refrigerant flow rate flowing in the hot-gas bypass 10V by opening and closing the second pressure-reducing portion V2, it is possible to maintain the balance between the amount of heat release of the refrigerant circuit 10 and the amount of heat input to the compressor 2. That is, the second pressure-reducing portion V2 functions as a flow rate adjusting portion that adjusts the flow rate of the refrigerant flowing in the hot-gas bypass 10V.

[0036] The refrigerant flow at the time of the hot-gas heating operation is depressurized by the third pressure-reducing portion V3 in the flow passage passing through the indoor heat exchanger 21, so it becomes high-pressure refrigerant on the upstream side of the third pressure-reducing portion V3 and low-pressure refrigerant on the downstream side of the third pressure-reducing portion V3. At this time, it is important for maintaining the heating capacity that no heat exchange is performed in the refrigerant heat medium heat exchanger 34 of the low-pressure side flow passage. Also, in the air conditioning unit 20, the air introduced by the supply fan 23 is heated by heat release in the indoor heat exchanger 21 and is blown out to the vehicle cabin.

[0037] [Control of the compressor at the time of the hot-gas heating operation] In the hot-gas heating operation of the vehicle air-conditioning apparatus 1, the control device 100 controls the compressor 2 by the fixed mode and the FF / FB mode. That is, the control device 100 executes the fixed mode at the hot-gas heating start, controls to drive the compressor 2 at a predetermined fixed rotation speed, and then executes the FF / FB mode, controls the compressor 2 by the FF control and the FB control to make the high-pressure side refrigerant pressure of the refrigerant circuit 10 (in the present embodiment, set to the outlet refrigerant pressure Pci of the indoor heat exchanger 21) the target pressure (target outlet refrigerant pressure PCO).

[0038] Hereinafter, the control of the compressor 2 at the hot-gas heating operation of the vehicle air-conditioning apparatus 1 is described in comparison with the reference example.

[0039] (Control method of reference example) Figure 6 A coordinate diagram showing an example of behavior of the outlet refrigerant pressure Pci (high-pressure side refrigerant pressure) of the indoor heat exchanger 21, the target rotation speed TGNC of the compressor 2, and the blowout temperature Tv at the hot-gas heating operation according to the control method of the reference example is shown. In addition, in the example of Figure 6 In the period indicated by "Mode 1", the fixed mode is executed, and in the period indicated by "Mode 2", the FF / FB mode is executed. In the following description, in the target rotation speed TGNC of the compressor 2, the fixed rotation speed TGNCf of the compressor 2 based on the fixed mode is set, and the target rotation speed TGNCz calculated by the control device 100 in the FF / FB mode is set.

[0040] In the period of Mode 1 shown in Figure 6 The control device 100 drives the compressor 2 at the target rotation speed TGNC as the fixed rotation speed TGNCf by the fixed mode, and along with this, the outlet refrigerant pressure Pci and the blowout temperature Tv rise. The control device 100 switches from the fixed mode to the FF / FB mode if it detects that the blowout temperature Tv rises and becomes above a predetermined threshold value, and controls the compressor 2 by the FF control and the FB control.

[0041] The control device 100 controls the rotation speed of the compressor 2 by the FF control and the FB control in the FF / FB mode. That is, the control device 100 calculates the target rotation speed TGNCz of the compressor 2 at each predetermined control period based on the difference between the target outlet refrigerant pressure PCO and the outlet refrigerant pressure Pci, and drives the compressor 2 at the calculated target rotation speed TGNCz.

[0042] Specifically, the control device 100 calculates the FF term TGNCh_FF as an FF operation amount of the target rotation speed TGNCz based on the outlet refrigerant pressure Pci and the target outlet refrigerant pressure PCO. Also, the control device 100 calculates an FB operation amount TGNCh_FB of the target rotation speed TGNCz by a PID (proportional integral derivative) operation or a PI (proportional integral) operation based on the outlet refrigerant pressure Pci and the target outlet refrigerant pressure PCO.

[0043] The control device 100 calculates the target rotation speed TGNCz of the compressor 2 by adding the FF term TGNCh_FF as an FF operation amount and the FB operation amount TGNCh_FB. That is, the target rotation speed TGNCz of the compressor 2 is represented by the following equation (1). TGNCz = TGNCh_FF + TGNCh_FB... (1)

[0044] Here, the FB operation amount TGNCh_FB includes a proportional term TGNCh_FB_P, an integral term TGNCh_FB_I, and a previous value of the integral term TGNCh_FB_Iz, but since there is no execution period of the FF / FB mode up to the FF / FB mode switching, the integral term TGNCh_FB_I and the previous value of the integral term TGNCh_FB_Iz of the FB operation amount TGNCh_FB are 0.

[0045] As a result thereof, the target rotation speed TGNCz calculated by the control device 100 is smaller than the fixed rotation speed TGNCf, and thus the target rotation speed TGNC of the compressor 2 temporarily decreases at the FF / FB mode switching from the fixed mode, and in conjunction therewith, the outlet refrigerant pressure Pci decreases, and thus the blowout temperature Tv also decreases. Then, the integral term is added with the execution of the FF / FB mode, and the target rotation speed TGNCz is adjusted based on the outlet refrigerant pressure Pci, but it takes time until the outlet refrigerant pressure Pci reaches the target outlet refrigerant pressure PCO, and it takes time until the blowout temperature Tv stabilizes (refer to Figure 6 ).

[0046] As such, at the FF / FB mode switching from the fixed mode, the target rotation speed TGNC of the compressor 2 fluctuates in a manner of temporarily decreasing or the like, and in conjunction therewith, the blowout temperature Tv also fluctuates, and thus the comfort of the user is impaired.

[0047] (Control method of the present embodiment) Therefore, in the present embodiment, the control device 100, at the FF / FB mode switching from the fixed mode at the hot-gas heating operation, suppresses the fluctuation of the target rotation speed TGNC of the compressor 2 at the hot-gas heating operation by performing the operation of the target rotation speed TGNCz of the compressor 2 based on the FF / FB mode as follows.

[0048] Figure 7 indicates an example of behavior of the outlet refrigerant pressure Pci of the indoor heat exchanger 21 (high-pressure side refrigerant pressure), the target rotation speed TGNC of the compressor 2, and the blow temperature Tv. The control device 100 controls the rotation speed of the compressor 2 by the fixed mode and the FF / FB mode, and in Figure 7 the example, the fixed mode is executed in the period indicated by "Mode 1", and the FF / FB mode is executed in the period indicated by "Mode 2". In Figure 7 the explanation, also in the target rotation speed TGNC of the compressor 2, the fixed rotation speed TGNCf of the compressor 2 based on the fixed mode is set, and the target rotation speed TGNCz calculated by the control device 100 in the FF / FB mode is set.

[0049] In the period of Mode 1 indicated in Figure 7 the control device 100 applies the fixed rotation speed TGNCf as the target rotation speed TGNC of the compressor 2 to drive. The control device 100 sets either one of the target rotation speed calculated based on the outside air temperature and the target rotation speed calculated based on the user setting as the fixed rotation speed TGNCf. The hot gas heating operation is executed in the case where the outside air temperature is extremely low, and thus both of the target rotation speed calculated based on the outside air temperature and the target rotation speed calculated based on the user setting become a high rotation speed range within which the compressor 2 can be driven.

[0050] In the fixed mode, since the compressor 2 is driven at a relatively high fixed rotation speed, the outlet refrigerant pressure Pci and the blow temperature Tv rise together relatively quickly, and thus the rapid warming property can be ensured. In the fixed mode, if the outlet refrigerant pressure Pci exceeds a predetermined threshold value, the control device 100 drives the blower 23 to start the air supply to the vehicle cabin. Thereby, in the indoor heat exchanger 21, the heat exchange of the high-temperature high-pressure refrigerant and the air passing through the indoor heat exchanger 21 is performed, the outlet refrigerant pressure Pci slightly drops, and rises again.

[0051] Then, the control device 100 switches from the fixed mode to the FF / FB mode if it detects that the blow temperature Tv rises and becomes equal to or higher than a predetermined threshold value, and controls the rotation speed of the compressor 2 by the FF control and the FB control. In the FF / FB mode, the control device 100 drives the compressor 2 at the target rotation speed TGNCz calculated in a predetermined control period. The control device 100 calculates the target rotation speed TGNCz by adding the FF operation amount TGNCh_FF and the FB operation amount TGNCh_FB calculated based on the outlet refrigerant pressure Pci and the target outlet refrigerant pressure PCO (the aforementioned formula (1)).

[0052] If the target rotation speed TGNC of the compressor 2 does not change at the time of switching to the FF / FB mode, i.e., the target rotation speed TGNCz at the time of switching to the FF / FB mode calculated by the control device 100 is a value approximately equal to the fixed rotation speed TGNCf in the fixed mode, the variation in the target rotation speed TGNC of the compressor 2 can be suppressed, and further, the variation in the outlet refrigerant pressure Pci and the blow temperature Tv can be suppressed.

[0053] As described above, at the time of switching to the FF / FB mode, the integral term in the FB operation amount TGNCh_FB is 0, and the target rotation speed is varied by the influence thereof, and therefore the control device 100 sets a predetermined initial value D to the integral term in the FB operation amount TGNCh_FB in order to compensate for this. Specifically, as shown in the following equation (2), the control device 100 sets the initial value D obtained by the fixed rotation speed TGNCf, the FF term TGNCh_FF, and the proportional term TGNCh_FB_P to the integral term in the FB operation amount TGNCh_FB. D = TGNCf - TGNCh_FF - TGNCh_FB_P... (2)

[0054] In addition, the control device 100 can use, as the initial value, a value calculated by simulation or the like and stored in advance in the ROM 102 or the like, as long as the target rotation speed TGNCz at the time of switching to the FF / FB mode becomes a value approximately equal to the fixed rotation speed TGNCf in the fixed mode.

[0055] The control device 100 makes the target rotation speed TGNCz obtained by adding the FB operation amount TGNCh_FB and the FF operation amount TGNCh_FF for which such an initial value D is set approximately equal to the fixed rotation speed TGNCf at the time of switching to the FF / FB mode. Therefore, the variation in the rotation speed of the compressor 2 at the time of switching from the fixed mode to the FF / FB mode is suppressed, and further, the variation in the outlet refrigerant pressure Pci and the blow temperature Tv is suppressed.

[0056] Thus, according to the present embodiment, at the time of hot-gas heating operation, the control device 100 drives the compressor 2 at a relatively high fixed rotation speed by the fixed mode at the start of hot-gas heating operation, and thereby can raise the outlet refrigerant pressure Pci at an early stage to ensure rapid warm-up. Further, the control device 100, if the blow temperature Tv is detected to exceed a predetermined threshold value during execution of the fixed mode, ensures responsiveness to disturbances by switching to the FF / FB mode.

[0057] Moreover, at the time of switching from the fixed mode to the FF / FB mode, a predetermined initial value D is set to the integral term of the FB manipulated variable TGNCh_FB, whereby a target rotation speed TGNCz that is approximately equal to the fixed rotation speed TGNCf in the fixed mode is calculated, and the compressor 2 is driven at the calculated target rotation speed TGNCz. Thus, at the time of switching from the fixed mode to the FF / FB mode, that is, at the time of switching the target rotation speed TGNC of the compressor 2 from the fixed rotation speed TGNCf to the target rotation speed TGNCz, the variation of the rotation speed of the compressor 2 is suppressed, and thus the variation of the outlet refrigerant pressure Pci and the blowout temperature Tv is also suppressed.

[0058] As described above, according to the present embodiment, it is possible to ensure the rapid warm-up property in the hot-gas heating operation, and to suppress the variation of the blowout temperature and to improve the comfort of the user.

[0059] The embodiments of the present application are described in detail above with reference to the accompanying drawings. However, the specific configuration is not limited to these embodiments, and design changes and the like within the scope of the gist of the present application are also included in the present application. Explanation of Reference Numerals

[0060] 1: Vehicle air-conditioning device, 2: Compressor, 10: Refrigerant circuit, 10V: Hot-gas bypass 11: Outside heat exchanger, 12, 13: Flow passage switching valve, 14, 15: Check valve 16: Accumulator, 20: Air-conditioning unit, 21, 22: Indoor heat exchanger 23: Blower, 24, 25: Damper, 25A, 25B: Air introduction port 30: Heat medium circuit, 31: Circulation pump, 33: Temperature adjustment target heat exchanger 34: Refrigerant heat medium heat exchanger, 34A, 34B: Flow passage, 40: Sensor section 41: Outside air sensor, 42: Compressor current sensor, 43: Refrigerant temperature sensor 44, 44A, 44B: Refrigerant pressure sensor, 45: Passenger sensor, 46: Blown temperature sensor 100: Control device

Claims

1. A vehicle air-conditioning apparatus including: a refrigerant circuit including a compressor, an indoor heat exchanger, and an outdoor heat exchanger; and a control device that controls the refrigerant circuit, wherein the refrigerant circuit has: a hot gas bypass that decompresses and returns at least a portion of refrigerant compressed by the compressor to the compressor without passing through the indoor heat exchanger and the outdoor heat exchanger; and a flow rate adjustment portion that adjusts a flow rate of refrigerant flowing in the hot gas bypass, the control device is capable of executing a hot gas heating mode in which a portion of refrigerant compressed by the compressor flows to the indoor heat exchanger and a remaining portion flows to the hot gas bypass, in the hot gas heating mode, the control device executes, after a fixed mode in which the compressor is driven at a predetermined fixed rotational speed is executed at the start of the hot gas heating mode, a feed-forward / feedback (FF / FB) mode in which a rotational speed of the compressor is controlled by feed-forward control and feedback control, and sets a predetermined initial value to an integral term of feedback control at the time of switching from the fixed mode to the FF / FB mode.

2. The vehicle air-conditioning apparatus according to claim 1, wherein the initial value is a value calculated based on a feed-forward term and a proportional term of a target rotational speed calculated in the FF / FB mode, and the fixed rotational speed.

3. The vehicle air-conditioning apparatus according to claim 1, wherein the control device executes the fixed mode with the fixed rotational speed set to a larger one of a target rotational speed calculated based on an outdoor air temperature and a target rotational speed calculated based on a user setting as a target rotational speed of the compressor.

4. The vehicle air-conditioning apparatus according to claim 1, wherein the control device switches from the fixed mode to the FF / FB mode when a blow-out temperature of air blown into a vehicle cabin is equal to or higher than a predetermined threshold value. ​ ​ ​ ​ ​ ​ ​ ​ ​

Images