Vehicle air conditioning device

Abstract

The present invention provides a vehicle air conditioner that effectively utilizes the heat of an object to be temperature-controlled during heating in a vehicle interior and suppresses the accumulation of refrigerant in an outdoor heat exchanger. The vehicle air conditioner includes: a refrigerant circuit including a compressor that compresses the refrigerant, a heating unit that heats the air blown to an air-conditioning target space, and an outdoor heat exchanger that absorbs heat of the refrigerant; an equipment temperature adjustment circuit including a heat exchanger for an object to be temperature-controlled that uses the refrigerant to adjust the temperature of an object to be temperature-controlled mounted on the vehicle; and a control device that controls the refrigerant circuit and the equipment temperature adjustment circuit. The control device at least has, during a heating operation in which the vehicle interior is heated using the heating unit: an object-to-be-temperature-controlled heat absorption heating mode in which the refrigerant discharged from the compressor and dissipated in the heating unit absorbs heat in the heat exchanger for the object to be temperature-controlled; and a combined heating mode in which the refrigerant discharged from the compressor and dissipated in the heating unit absorbs heat in the outdoor heat exchanger and the heat exchanger for the object to be temperature-controlled. The control device performs control so that, during a heating operation based on the combined heating mode, when it determines an operating state in which the refrigerant may accumulate in the outdoor heat exchanger, it switches to the object-to-be-temperature-controlled heat absorption heating mode to perform the heating operation.

Description

Technical Field

[0001] The present invention relates to a vehicle air conditioning device of a heat pump type, and more particularly to a vehicle air conditioning device that can absorb heat from temperature-controlled objects such as a battery and a motor mounted on a vehicle to heat the interior of the vehicle. Background Art

[0002] In recent years, vehicles such as hybrid vehicles and electric vehicles that are driven by electric power supplied from a battery mounted on a vehicle have been popularized. As an air conditioning device applied to such vehicles, an air conditioning device having a refrigerant circuit is known (for example, Patent Document 1). The refrigerant circuit is connected to a compressor that compresses and discharges a refrigerant, a radiator (indoor heat exchanger) disposed in the vehicle interior that dissipates heat of the refrigerant, and an outdoor heat exchanger disposed outside the vehicle that ventilates external air and absorbs or dissipates heat of the refrigerant. In such a vehicle air conditioning device, heating is performed by causing the refrigerant discharged from the compressor and cooled by dissipating heat in the radiator to absorb heat in the outdoor heat exchanger, and the refrigerant discharged from the compressor and cooled by dissipating heat in the outdoor heat exchanger is evaporated in an absorber (evaporator) to absorb heat for refrigeration, etc., thereby performing air conditioning in the vehicle interior.

[0003] In addition, for example, a vehicle air conditioning device is known: a heat exchanger for a temperature-controlled object that cools a temperature-controlled object such as a battery is provided in a refrigerant circuit, and an external air heat absorption heating mode in which heat absorption of the refrigerant during heating operation is performed only by the outdoor heat exchanger, a heat exchanger for a temperature-controlled object heating mode in which heat absorption of the refrigerant during heating operation is performed only by the heat exchanger for a temperature-controlled object, and a combined heating mode in which heat absorption of the refrigerant during heating operation is performed by both the outdoor heat exchanger and the heat exchanger for a temperature-controlled object are switched and executed (for example, Patent Document 2).

[0004] Prior Art Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-213765

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2020-050155

[0007] In the combined heating mode of the above vehicle air conditioning device, when the refrigerant is circulated through both the outdoor heat exchanger and the heat exchanger for a temperature-controlled object, the refrigerant discharged from the compressor and cooled by dissipating heat in the radiator is branched into a flow path toward the outdoor heat exchanger and a flow path toward the heat exchanger for a temperature-controlled object. Thereafter, the branched refrigerant absorbs heat in the outdoor heat exchanger and the heat exchanger for a temperature-controlled object and flows into the compressor again.

[0008] That is, since the refrigerant after the flow division flows into the outdoor heat exchanger, the refrigerant after the flow division flows out at the outlet of the outdoor heat exchanger. On the other hand, the refrigerant circulated from the outdoor heat exchanger and the refrigerant circulated from the heat exchanger for the temperature-controlled object merge and flow into the inlet of the compressor. Therefore, the amount of the circulated refrigerant is different at the outlet of the outdoor heat exchanger and the inlet of the compressor. In addition, the amount of heat absorbed in the outdoor heat exchanger and the amount of heat absorbed in the heat exchanger for the temperature-controlled object are not necessarily the same, so the temperature and pressure of the refrigerant flowing out of each heat exchanger are not necessarily the same.

[0009] Due to such a background, when operating in the combined heating mode, the refrigerant (liquid refrigerant, oil) may sometimes accumulate in the outdoor heat exchanger. If the refrigerant accumulates more than a certain amount in the outdoor heat exchanger, the amount of the refrigerant circulating in the refrigerant circuit will be insufficient, and there may be a reduction in heating performance, a reduction in the durability of the compressor or a failure, and a false detection of refrigerant shortage. Summary of the Invention

[0010] Based on the above problems, the subject of the present invention is to effectively utilize the heat of the temperature-controlled object during heating in the vehicle interior and suppress the accumulation of the refrigerant in the outdoor heat exchanger, etc.

[0011] The present invention provides a vehicle air-conditioning device, comprising: a refrigerant circuit including a compressor for compressing the refrigerant, a heating unit for heating the air supplied to the air-conditioning target space, and an outdoor heat exchanger for absorbing the heat of the refrigerant; an equipment temperature adjustment circuit including a heat exchanger for the temperature-controlled object for adjusting the temperature of the temperature-controlled object mounted on the vehicle using the refrigerant; and a control device for controlling the refrigerant circuit and the equipment temperature adjustment circuit. During the heating operation of heating the interior of the vehicle using the heating unit, the control device at least has: a temperature-controlled object heat absorption heating mode in which the refrigerant discharged from the compressor and dissipated heat in the heating unit absorbs heat in the heat exchanger for the temperature-controlled object; and a combined heating mode in which the refrigerant discharged from the compressor and dissipated heat in the heating unit absorbs heat in the outdoor heat exchanger and the heat exchanger for the temperature-controlled object. The control device performs control so that during the heating operation based on the combined heating mode, when determining the operating state in which the refrigerant may accumulate in the outdoor heat exchanger, it switches to the temperature-controlled object heat absorption heating mode to perform the heating operation.

[0012] According to the present invention, it is possible to effectively utilize the heat of the temperature-controlled object during heating in the vehicle interior and suppress the accumulation of the refrigerant in the outdoor heat exchanger. Brief Description of the Drawings

[0013] Figure 1This is a diagram showing the schematic structure of the vehicle air conditioner according to an embodiment of the present invention.

[0014] Figure 2 This is a block diagram showing the schematic structure of the air conditioner controller which is the control device of the vehicle air conditioner according to an embodiment of the present invention.

[0015] Figure 3 This is an explanatory diagram showing the flow of the refrigerant during the heating operation in the external air heat absorption heating mode in the vehicle air conditioner according to an embodiment of the present invention.

[0016] Figure 4 This is an explanatory diagram showing the flow of the refrigerant during the heating operation in the combined heating mode in the vehicle air conditioner according to an embodiment of the present invention.

[0017] Figure 5 This is an explanatory diagram showing the flow of the refrigerant during the heating operation in the heat absorption heating mode by the temperature adjustment target in the vehicle air conditioner according to an embodiment of the present invention. Detailed Embodiments

[0018] Hereinafter, the embodiments for implementing the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals denote parts having the same functions, and redundant descriptions in each drawing will be appropriately omitted.

[0019] Figure 1 This shows the schematic structure of the vehicle air conditioner 1 according to an embodiment of the present invention. The vehicle air conditioner 1 can be applied, for example, to electric vehicles (EVs) not equipped with an engine (internal combustion engine), and vehicles such as so-called hybrid vehicles equipped with an engine and an electric motor for driving. Such vehicles are equipped with a battery 55 (for example, a lithium battery), and are driven by supplying the electric power charged from an external power source to the battery 55 to a motor unit 65 including a driving motor (electric motor). The vehicle air conditioner 1 is also driven by the battery 55.

[0020] The vehicle air conditioner 1 includes a refrigerant circuit R for performing heat pump operation, and an equipment temperature adjustment circuit 61 for adjusting the temperature of temperature adjustment targets such as the battery 55 and the motor unit 65. The equipment temperature adjustment circuit 61 is a parallel circuit with respect to the refrigerant circuit R by means of a refrigerant and heat medium heat exchanger 64 described later. The vehicle air conditioner 1 selectively executes various operation modes including air conditioning operations such as heating operation and cooling operation by using the heat pump operation of the refrigerant circuit R, thereby performing air conditioning in the vehicle interior and temperature adjustment of temperature adjustment targets such as the battery 55 and the motor unit 65.

[0021] The refrigerant circuit R is constituted by connecting the following components through refrigerant pipes 13A to 13H: an electric compressor 2 that compresses the refrigerant; a radiator 4 as an indoor heat exchanger (heating section) disposed in the air flow passage 3 of the HVAC unit 10 through which the air in the vehicle interior circulates, which cools the high-temperature and high-pressure refrigerant discharged from the compressor 2 to heat the air supplied to the vehicle interior; an outdoor expansion valve 6 that decompresses and expands the refrigerant during heating; an outdoor heat exchanger 7 that exchanges heat between the refrigerant and the outside air, functioning as a radiator (condenser) that cools the refrigerant during cooling and as an evaporator that absorbs heat from the refrigerant during heating; an indoor expansion valve 8 that decompresses and expands the refrigerant; a heat absorber 9 disposed in the air flow passage 3 that cools the refrigerant by absorbing heat from the vehicle interior and exterior during cooling (dehumidifying) to cool the air supplied to the vehicle interior; and a liquid receiver 12, etc.

[0022] Both the outdoor expansion valve 6 and the indoor expansion valve 8 can be an electronic expansion valve. The outdoor expansion valve 6 decompresses and expands the refrigerant flowing out of the radiator 4 and flowing into the outdoor heat exchanger 7, and can also be fully closed. The indoor expansion valve 8 decompresses and expands the refrigerant flowing into the heat absorber 9, and adjusts the heat absorption capacity of the refrigerant in the heat absorber 9, that is, the cooling capacity through the air.

[0023] The refrigerant outlet of the outdoor heat exchanger 7 and the refrigerant inlet of the heat absorber 9 are connected by the refrigerant pipe 13A. In the refrigerant pipe 13A, a check valve 18 and an indoor expansion valve 8 are sequentially provided from the outdoor heat exchanger 7 side. The check valve 18 is provided in the refrigerant pipe 13A with the direction toward the heat absorber 9 as the forward direction. The refrigerant pipe 13A branches off a refrigerant pipe 13B at a position closer to the outdoor heat exchanger 7 than the check valve 18.

[0024] The refrigerant pipe 13B branched off from the refrigerant pipe 13A is connected to the refrigerant inlet of the liquid receiver 12. In the refrigerant pipe 13B, a solenoid valve 21 that opens during heating and a check valve 20 are sequentially provided from the outdoor heat exchanger 7 side. The check valve 20 is connected with the direction toward the liquid receiver 12 as the forward direction. A refrigerant pipe 13C branches off between the solenoid valve 21 and the check valve 20 of the refrigerant pipe 13B. The refrigerant pipe 13C branched off from the refrigerant pipe 13B is connected to the refrigerant outlet of the heat absorber 9. The refrigerant outlet of the liquid receiver 12 and the compressor 2 are connected by the refrigerant pipe D.

[0025] The refrigerant outlet of the compressor 2 and the refrigerant inlet of the radiator 4 are connected by a refrigerant pipe 13E. One end of a refrigerant pipe 13F is connected to the refrigerant outlet of the radiator 4, and the other end side of the refrigerant pipe 13F branches into a refrigerant pipe 13G and a refrigerant pipe 13H on the front side (refrigerant upstream side) of the outdoor expansion valve 6. One of the branched refrigerant pipes 13H is connected to the refrigerant inlet side of the outdoor heat exchanger 7 via the outdoor expansion valve 6. In addition, the other branched refrigerant pipe 13G is connected between the check valve 18 of the refrigerant pipe A and the indoor expansion valve 8. An electromagnetic valve 22 is provided on the refrigerant pipe 13G on the refrigerant upstream side of the connection point with the refrigerant pipe A.

[0026] Thus, the refrigerant pipe 13G is connected in parallel to the series circuit of the outdoor expansion valve 6, the outdoor heat exchanger 7, and the check valve 18, forming a circuit that bypasses the outdoor expansion valve 6, the outdoor heat exchanger 7, and the check valve 18.

[0027] In the air flow passage 3 on the air upstream side of the heat absorber 9, there are formed intake ports such as an outside air intake port and an inside air intake port (represented by the intake port 25 in Figure 1 ). An intake switching damper 26 is provided at the intake port 25. By using the intake switching damper 26, the inside air (inside air circulation) as the air in the vehicle interior and the outside air (outside air introduction) as the air outside the vehicle are appropriately switched, and the air is introduced into the air flow passage 3 from the intake port 25. An indoor blower (fan) 27 for supplying the introduced inside air and outside air to the air flow passage 3 is provided on the air downstream side of the intake switching damper 26.

[0028] In Figure 1 , the auxiliary heater 23 is an auxiliary heater as an auxiliary heating device. The auxiliary heater 23 is constituted by, for example, a PTC heater (electric heater), and is provided in the air flow passage 3 on the air downstream side of the radiator 4 with respect to the air flow in the air flow passage 3. When the auxiliary heater 23 is energized and heated, it becomes a so-called heater core, supplementing the heating in the vehicle interior.

[0029] An air mixing damper 28 is provided in the air flow passage 3 on the air upstream side of the radiator 4, and the air mixing damper 28 adjusts the ventilation ratio of the air (inside air, outside air) in the air flow passage 3 that flows into the air flow passage 3 and passes through the heat absorber 9 to the radiator 4 and the auxiliary heater 23.

[0030] The device temperature adjustment circuit 61 circulates a heat medium to temperature-regulated objects such as the battery 55 and the motor unit 65 to adjust the temperatures of the battery 55 and the motor unit 65. In addition, the motor unit 65 also includes heat-generating devices such as an electric motor for driving and an inverter circuit for driving the electric motor. As temperature-regulated objects, in addition to the battery 55 and the motor unit 65, devices mounted on the vehicle and generating heat can also be applied.

[0031] The device temperature adjustment circuit 61 includes: a first circulation pump 62 and a second circulation pump 63 as circulation devices for circulating the heat medium to the battery 55 and the motor unit 65, a refrigerant-heat medium heat exchanger (hereinafter referred to as "cooling heat exchanger") 64, a heat medium heater 66, an air-heat medium heat exchanger 67, and a three-way valve 81 as a flow path switching device.

[0032] The device temperature adjustment circuit 61 is connected to the refrigerant circuit R via the cooling heat exchanger 64. In the refrigerant circuit R, one end of a branch pipe 72 as a branch circuit is connected between the connection point of the refrigerant pipe 13A connected to the refrigerant pipe G and the indoor expansion valve 8, and the other end of the branch pipe 72 is connected to the refrigerant flow path of the cooling heat exchanger 64. An auxiliary expansion valve 73 is provided on the branch pipe 72. The auxiliary expansion valve 73 decompresses and expands the refrigerant flowing into the refrigerant flow path of the cooling heat exchanger 64, and can also be fully closed.

[0033] One end of a refrigerant pipe 74 is connected to the outlet of the refrigerant flow path of the cooling heat exchanger 64, and the other end of the refrigerant pipe 74 is connected between the check valve 20 and the accumulator 12 of the refrigerant pipe B. The cooling heat exchanger 64 forms a part of the refrigerant circuit R and also forms a part of the device temperature adjustment circuit 61.

[0034] One end of a heat medium pipe 68A is connected to the heat medium discharge side of the cooling heat exchanger 64. In the heat medium pipe 68A, a heat medium heater 66, a battery 55, a first circulation pump 62, and a check valve 82 are provided in sequence from the cooling heat exchanger 64 side. The other end of the heat medium pipe 68A is connected to a heat medium pipe 68B described later. The heat medium pipe 68A branches into a heat medium pipe 68B at a position closer to the cooling heat exchanger 64 than the heat medium heater 66. The other end of the branched heat medium pipe 68B is connected to the heat medium inlet of the cooling heat exchanger 64. An air-heat medium heat exchanger 67 is provided on the heat medium pipe 68B. The air-heat medium heat exchanger 67 is arranged on the downwind side of the outdoor heat exchanger 7 with respect to the flow (air duct) of external air (air) ventilated by an outdoor blower (not shown).

[0035] A three-way valve 81 is provided on the downstream side of the heat medium piping 68B with respect to the air-to-heat medium heat exchanger 67 and closer to the heat medium. The other end of the heat medium piping A is connected between the three-way valve 81 of the heat medium piping 68B and the heat medium inlet of the cooling heat exchanger 64. On the upstream side of the heat medium piping 68B with respect to the air-to-heat medium heat exchanger 67 and closer to the heat medium, the heat medium piping 68B branches into a heat medium piping C, and the other end of the branched heat medium piping C is connected to the three-way valve 81. A second circulation pump 63 and a motor unit 65 are provided on the heat medium piping C.

[0036] As the heat medium used in the equipment temperature adjustment circuit 61, for example, liquids such as water, refrigerants such as HFO-1234yf, coolants, and gases such as air can be used. In addition, in the present embodiment, water is used as the heat medium. Furthermore, around the battery 55 and the motor unit 65, for example, a sleeve structure is implemented in which the heat medium can flow in a heat exchange relationship with the battery 55 and the motor unit 65.

[0037] If the three-way valve 81 is switched to a state where the inlet communicates with the outlet on the side of the cooling heat exchanger 64 and the second circulation pump 63 is operated, the heat medium discharged from the second circulation pump 63 sequentially flows through the heat medium piping 64C, the motor unit 65, the three-way valve 81, the heat medium piping 68B, the heat medium flow path of the cooling heat exchanger 64, and the heat medium piping 68B, and is sucked into the second circulation pump 63. In such a flow path control state, the heat medium circulates between the motor unit 65 and the cooling heat exchanger 64.

[0038] When the auxiliary expansion valve 73 is opened, a part or all of the refrigerant flowing out from the refrigerant piping 13G and the outdoor heat exchanger 7 flows into the refrigerant flow path of the cooling heat exchanger 64 and evaporates after flowing into the branch piping 72 and being decompressed by the auxiliary expansion valve 73. After the refrigerant absorbs heat from the heat medium flowing through the heat medium flow path during the process of flowing through the refrigerant flow path of the cooling heat exchanger 64, it is sucked into the compressor 2 through the accumulator 12.

[0039] In addition, as the heating unit, in addition to the indoor heat exchanger, for example, a method of heating the supply air by circulating warm water heated by the waste heat of the compressor through the heater core can also be adopted.

[0040] Figure 2 The schematic structure of the air conditioner controller 32 is shown. The air conditioner controller 32 is a control device responsible for controlling the vehicle air conditioner 1. The air conditioner controller 32 is connected to the vehicle controller 35 (ECU) responsible for the overall vehicle control including the drive control of the motor unit 65 and the charge and discharge control of the battery 55 via the vehicle communication bus, and information is transmitted and received. Both the air conditioner controller 32 and the vehicle controller 35 (ECU) can be implemented as a microcomputer as an example of a computer equipped with a processor.

[0041] The air conditioner controller 32 (control device) is connected to the following various sensors and detectors, and the outputs of the various sensors, detectors, etc. are input thereto. That is, the air conditioner controller 32 (control device) is connected to: an outside air temperature sensor 33 that detects the outside air temperature (Tam) of the vehicle; an HVAC intake temperature sensor 36 that detects the temperature of the air flowing through the air passage 3 sucked from the intake port 25; an inside air temperature sensor 37 that detects the temperature of the air (inside air) in the vehicle interior; a blow-out temperature sensor 41 that detects the temperature of the air blown into the vehicle interior from the blow-out port 29; a discharge pressure sensor 42 that detects the discharge refrigerant pressure (discharge pressure Pd) of the compressor 2; a discharge temperature sensor 43 that detects the discharge refrigerant temperature of the compressor 2; a suction temperature sensor 44 that detects the suction refrigerant temperature TS of the compressor 2; a radiator temperature sensor 46 that detects the temperature of the radiator 4 (the temperature of the refrigerant passing through the radiator 4 or the temperature of the radiator 4 itself: radiator temperature TCI); a radiator pressure sensor 47 that detects the refrigerant pressure of the radiator 4 (the pressure of the refrigerant in the radiator 4 or immediately after flowing out of the radiator 4: radiator pressure PCI); an absorber temperature sensor 48 that detects the temperature of the absorber 9 (the temperature of the air passing through the absorber 9 or the temperature of the absorber 9 itself: absorber temperature Te); an absorber pressure sensor 49 that detects the refrigerant pressure of the absorber 9 (the pressure of the refrigerant in the absorber 9 or immediately after flowing out of the absorber 9); for example, a sunlight sensor 51 of a photosensor type that is used to detect the amount of sunlight entering the vehicle interior; a vehicle speed sensor 52 that is used to detect the moving speed (vehicle speed) of the vehicle; an air conditioner operation unit 53 that is used to set the set temperature and the switching of the air conditioner operation; an outdoor heat exchanger temperature sensor 54 that detects the temperature of the outdoor heat exchanger 7 (in the present embodiment, the discharge refrigerant temperature TXO immediately after discharging from the outdoor heat exchanger 7); and an outdoor heat exchanger pressure sensor 56 that detects the refrigerant pressure of the outdoor heat exchanger 7 (in the present embodiment, the discharge refrigerant pressure value PXO immediately after discharging from the outdoor heat exchanger 7).

[0042] In addition to the above, the air conditioner controller 32 is further connected to: a battery temperature sensor 76 that detects the temperature of the battery 55 (any one of the temperature of the battery 55 itself, the temperature of the heat medium flowing out of the battery 55, and the temperature of the heat medium entering the battery 55: battery temperature Tb); a heat medium outlet temperature sensor that detects the temperature of the heat medium flowing through the heat medium passage of the cooling heat exchanger 64; and a motor temperature sensor 78 that detects the temperature of the motor unit 65 (any one of the temperature of the motor unit 65 itself, the temperature of the heat medium flowing out of the motor unit 65, and the temperature of the heat medium entering the motor unit 65: motor temperature Tw).

[0043] On the other hand, the output of the air-conditioning controller 32 is connected to the compressor 2, the outdoor blower, the indoor blower (blower) 27, the intake switching damper 26, the air mix damper 28, the outlet switching damper 31, the outdoor expansion valve 6, the indoor expansion valve 8, the solenoid valves 21, 22 of the respective solenoid valves, the auxiliary heater 23, the first and second circulation pumps 62, 63, the auxiliary expansion valve 73, and the three-way valve 81. And the air-conditioning controller 32 controls the above components based on the outputs of the respective sensors, the settings input in the air-conditioning operation unit 53, and the information from the vehicle controller 35.

[0044] Hereinafter, the operation of the vehicle air-conditioning device 1 configured as described above, particularly the operation during heating operation, will be described. The air-conditioning controller 32 (control device) in the present embodiment can switch and execute an outside-air heat-absorbing heating mode (heating mode) that absorbs heat only through the outdoor heat exchanger 7, a combined heating mode (waste heat recovery parallel mode) that absorbs heat through the outdoor heat exchanger 7 and the cooling heat exchanger 64, and a heat-absorbing heating mode for the object to be temperature-controlled (waste heat recovery single mode) that absorbs heat only through the cooling heat exchanger 64 during heating operation.

[0045] Hereinafter, each heating mode will be described.

[0046] (1) Outside-air heat-absorbing heating mode (heating mode)

[0047] Figure 3 The flow of the refrigerant in the refrigerant circuit R in the outside-air heat-absorbing heating mode is shown (solid-line arrow). When heating operation is selected using the air-conditioning controller 32 (automatic mode) or manual operation of the air-conditioning operation unit 53 (manual mode), and the outside-air heat-absorbing heating mode is executed by the air-conditioning controller 32, the solenoid valve 21 (for heating) is opened, and the indoor expansion valve 8 is fully closed. In addition, the auxiliary expansion valve 73 is fully closed, and the solenoid valve 22 (for dehumidification) is also closed.

[0048] The compressor 2 and the blower 27 are operated, and the air mix damper 28 is in a state of adjusting the ratio of the air blown out from the indoor blower 27 to ventilate the radiator 4 and the auxiliary heater 23. As a result, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 2 flows into the radiator 4. Since the air in the air flow passage 3 ventilates the radiator 4, the air in the air flow passage 3 is heated by the high-temperature refrigerant in the radiator 4. On the other hand, the refrigerant in the radiator 4 is deprived of heat by the air and is cooled, thereby condensing and liquefying.

[0049] After the refrigerant liquefied in the radiator 4 flows out of the radiator 4, it reaches the outdoor expansion valve 6 through the refrigerant pipes 13F and 13H. The refrigerant is decompressed by the outdoor expansion valve 6 and then flows into the outdoor heat exchanger 7. The refrigerant flowing into the outdoor heat exchanger 7 evaporates and absorbs heat (heat absorption) from the outside air flowing in due to driving or the outside air ventilated by an outdoor blower (not shown). That is, the refrigerant circuit R becomes a heat pump.

[0050] And the low-temperature refrigerant flowing out of the outdoor heat exchanger 7 flows into the accumulator 12 through the refrigerant pipes 13A, 13B, solenoid valve 21, and check valve 20. After the refrigerant is gas-liquid separated by passing through the accumulator 12, the cycle of the gaseous refrigerant being sucked into the compressor 2 through the refrigerant pipe 13D is repeated. The air heated by the radiator 4 is blown out from the air outlet 29. Thus, heating in the vehicle interior is performed.

[0051] The air-conditioning controller 32 calculates the target radiator pressure PCO (the target value of the pressure PCI of the radiator 4) based on the target heater temperature TCO (the target value of the air temperature on the downstream side of the radiator 4) calculated from the target blow-out temperature TAO, and controls the rotational speed of the compressor 2 based on the target radiator pressure PCO and the refrigerant pressure of the radiator 4 (the radiator pressure PCI, the high-pressure pressure of the refrigerant circuit R) detected by the radiator pressure sensor 47. Also, based on the temperature of the radiator 4 (the radiator temperature TCI) detected by the radiator temperature sensor 46 and the radiator pressure PCI detected by the radiator pressure sensor 47, the valve opening degree of the outdoor expansion valve 6 is controlled to control the subcooling degree of the refrigerant at the outlet of the radiator 4. The target heater temperature TCO is basically TCO = TAO, but there are specified restrictions for control. In addition, when the heating capacity of the radiator 4 is insufficient, the auxiliary heater 23 is energized to generate heat to supplement the heating capacity.

[0052] (2) Combined heating mode (waste heat recovery parallel mode)

[0053] Figure 4 The flow of the refrigerant in the refrigerant circuit R and the flow of the heat medium in the equipment temperature adjustment circuit 61 in the combined heating mode are shown. In the combined heating mode, the air-conditioning controller 32 is in Figure 3 the state of the external air heat absorption heating mode during the heating operation of the refrigerant circuit R shown, further opens the solenoid valve 22, and also opens the auxiliary expansion valve 73 and is in the state of controlling its valve opening degree. Thus, a part of the refrigerant flowing out of the radiator 4 is branched on the upstream side of the refrigerant of the outdoor expansion valve 6 and flows into the refrigerant pipe 13A through the refrigerant pipe 13G.

[0054] The refrigerant flowing into the refrigerant pipe 13A enters the branch pipe 72, is decompressed by passing through the auxiliary expansion valve 73, and then flows into the refrigerant flow path of the cooling heat exchanger 64 through the branch pipe 72 and evaporates. At this time, it plays an endothermic role. The following cycle is repeated: The refrigerant evaporated in the refrigerant flow path enters the downstream side of the check valve 20 of the refrigerant pipe 13B through the refrigerant pipe 74, and is sucked into the compressor 2 through the accumulator 12 and the refrigerant pipe 13D.

[0055] On the other hand, as Figure 4 shown, the heat medium in the equipment temperature adjustment circuit 61 is discharged from the second circulation pump 63 to the heat medium pipe 68C and reaches the motor unit 65. After heat exchange with the motor unit 65, it reaches the heat medium flow path of the cooling heat exchanger 64 through the three-way valve 81. The heat medium is cooled by the refrigerant that evaporates in the refrigerant flow path of the cooling heat exchanger 64. The heat medium cooled by the endothermic action of the refrigerant repeatedly circulates out of the cooling heat exchanger 64 and is sucked into the second circulation pump 63.

[0056] In this way, in the combined heating mode, the outdoor heat exchanger 7 and the cooling heat exchanger 64 are connected in parallel with respect to the flow of the refrigerant in the refrigerant circuit R. Therefore, the refrigerant flows to the outdoor heat exchanger 7 and the cooling heat exchanger 64 and evaporates respectively. Therefore, heat is absorbed from the outside air through the outdoor heat exchanger 7, and heat is also absorbed from the heat medium (motor unit 65) through the cooling heat exchanger 64. Thus, it is possible to absorb heat from the motor unit 65 (the object to be temperature-controlled) via the heat medium, cool the motor unit 65 while delivering the absorbed heat to the radiator 4 for heating in the vehicle interior.

[0057] (3) Object to be temperature-controlled endothermic heating mode (waste heat recovery single mode)

[0058] Figure 5 The flow of the refrigerant in the refrigerant circuit R and the flow of the heat medium in the equipment temperature adjustment circuit 61 in the object to be temperature-controlled endothermic heating mode are shown.

[0059] In this object to be temperature-controlled heating mode, the air-conditioning controller 32 closes the solenoid valve 21 (it can also be opened because of the check valve 20), fully closes the outdoor expansion valve 6 and the indoor expansion valve 8, opens the solenoid valve 22, and also opens the auxiliary expansion valve 73 and is in a state of controlling its valve opening. The compressor 2 and the indoor blower 27 are operated (the heat medium heater 66 is not powered on).

[0060] Thus, all the refrigerant flowing out of the radiator 4 flows toward the solenoid valve 22 and enters the refrigerant pipe 13A through the refrigerant pipe 13G. The refrigerant then enters the branch pipe 72, is decompressed by passing through the auxiliary expansion valve 73, and then flows into the refrigerant flow path of the cooling heat exchanger 64 through the branch pipe 72 and evaporates. At this time, the heat absorption effect is exerted. The following cycle is repeated: The refrigerant evaporated in the refrigerant flow path flows into the downstream side of the check valve 20 of the refrigerant pipe 13B through the refrigerant pipe 74, passes through the accumulator 12 and the refrigerant pipe 13D, and is sucked into the compressor 2.

[0061] On the other hand, as Figure 5 shown, the heat medium in the equipment temperature adjustment circuit 61 is discharged from the second circulation pump 63 to the heat medium pipe 68C and reaches the motor unit 65. After exchanging heat with the motor unit 65, it reaches the heat medium flow path of the cooling heat exchanger 64 through the three-way valve 81. The heat medium is cooled by being absorbed by the refrigerant evaporated in the refrigerant flow path of the cooling heat exchanger 64. The heat medium cooled by the heat absorption of the refrigerant repeatedly circulates out of the cooling heat exchanger 64 and is sucked into the second circulation pump 63.

[0062] In this way, in the waste heat recovery single mode, the refrigerant in the refrigerant circuit R evaporates in the cooling heat exchanger 64 and only absorbs heat from the heat medium of the equipment temperature adjustment circuit 61. That is, the refrigerant does not flow into the outdoor heat exchanger 7 and evaporate. The refrigerant only absorbs heat from the motor unit 65 via the heat medium. Therefore, the problem of frosting on the outdoor heat exchanger 7 can be eliminated, and the motor unit 65 can be cooled. The heat absorbed from the motor unit 65 (the object to be temperature-regulated) is transferred to the radiator 4 to heat the vehicle interior.

[0063] (4) Mode switching during heating operation

[0064] The air-conditioning controller 32 switches between the heating modes, for example, in the following cases.

[0065] When the vehicle air-conditioning device 1 operates in the normal heating mode, in a situation where sufficient waste heat can be recovered from the motor unit 65 (the temperature Tw of the heat medium (cooling water) entering the motor unit 65 > 30 deg and there is a waste heat recovery requirement), it switches to the waste heat recovery parallel mode.

[0066] When the vehicle air-conditioning device 1 operates in the waste heat recovery parallel mode, in a situation where waste heat recovery cannot be performed (Tw < -5 deg or Tw < the outside air temperature Tam of the vehicle or there is no waste heat recovery requirement), the air-conditioning controller 32 determines that the waste heat recovery is completed and switches from the waste heat recovery parallel mode to the normal heating mode.

[0067] When the vehicle air conditioner 1 operates in the waste heat recovery parallel mode, if the water temperature continues to rise (Tw > 60 deg and there is a waste heat recovery requirement), it transfers to the waste heat recovery single mode.

[0068] Here, during operation based on the waste heat recovery parallel mode, depending on the operating conditions, refrigerant and oil contained in the refrigerant may sometimes accumulate in the outdoor heat exchanger 7. If the refrigerant etc. accumulates in the outdoor heat exchanger by a certain amount or more, the amount of refrigerant circulating in the refrigerant circuit R becomes insufficient, and there may be a reduction in heating performance, a reduction in the durability of the compressor or a malfunction, a false detection of refrigerant shortage, etc.

[0069] Therefore, during the heating operation based on the waste heat recovery parallel mode, when the air conditioning controller 32 determines that the operating condition is a state where refrigerant may accumulate in the outdoor heat exchanger, it switches to the waste heat recovery single mode to perform the heating operation.

[0070] During the heating operation based on the waste heat recovery parallel mode, as a state where refrigerant may accumulate in the outdoor heat exchanger, there is an operating state in which the discharged refrigerant pressure value PXO of the outdoor heat exchanger is smaller than the suction refrigerant pressure value PS of the compressor for a certain period of time or more.

[0071] When the compressor operates at a speed below a specified speed, or when the compressor operates intermittently, the amount of refrigerant circulating in the refrigerant circuit R decreases, and the discharged refrigerant pressure value PXO of the outdoor heat exchanger 7 becomes smaller than the suction refrigerant pressure value PS of the compressor 2, resulting in a state where refrigerant may accumulate in the outdoor heat exchanger 7.

[0072] In addition, even when the heat absorption amount of the refrigerant in the cooling heat exchanger 64 is larger than the heat absorption amount of the refrigerant in the outdoor heat exchanger 7 for a certain period of time or more, the discharged refrigerant pressure value PXO of the outdoor heat exchanger 7 is also smaller than the suction refrigerant pressure value PS of the compressor 2, resulting in a state where refrigerant may accumulate in the outdoor heat exchanger 7.

[0073] Therefore, the air conditioning controller 32 monitors the discharged refrigerant pressure value PXO of the outdoor heat exchanger 7 and the suction refrigerant pressure value PS of the compressor 2. The discharged refrigerant pressure value PXO can use the discharged refrigerant pressure value PXO obtained from the outdoor heat exchanger pressure sensor 56, and the suction refrigerant pressure value PS can use the suction refrigerant pressure value PS calculated based on the suction refrigerant temperature TS obtained from the suction temperature sensor 44 and the refrigerant saturation temperature.

[0074] When the state where the discharged refrigerant pressure value PXO of the outdoor heat exchanger 7 is less than the suction refrigerant pressure value PS of the compressor 2, or the state where the discharged refrigerant temperature TXO of the outdoor heat exchanger 7 is less than the suction refrigerant temperature TS of the compressor 2 exceeds a predetermined time, the air-conditioning controller 32 switches from the waste heat recovery parallel mode to the waste heat recovery single mode to perform heating operation.

[0075] In addition, the discharged refrigerant pressure value PXO can be calculated using the discharged refrigerant temperature TXO obtained from the outdoor heat exchanger temperature sensor 54 and the refrigerant saturation temperature, or a pressure sensor can be provided at the suction port of the compressor 2 to directly detect the suction refrigerant pressure value PS.

[0076] Furthermore, the air-conditioning controller 32 can also monitor the discharged refrigerant temperature TXO of the outdoor heat exchanger 7 and the suction refrigerant temperature TS of the compressor 2. In this case, the discharged refrigerant temperature TXO can be calculated not only using the discharged refrigerant pressure value PXO detected by the outdoor heat exchanger pressure sensor 56 and the saturation temperature, but also using the discharged refrigerant temperature TXO directly detected by the outdoor heat exchanger temperature sensor 54. In addition, the suction refrigerant temperature TS can be calculated not only using the suction refrigerant pressure value PS directly detected by providing a pressure sensor at the suction port of the compressor 2 and the saturation temperature, but also using the suction refrigerant temperature TS directly detected by the suction temperature sensor 44.

[0077] In addition, the air-conditioning controller 32 monitors the operating conditions such as the rotational speed of the compressor 2, for example. When the compressor operates at a speed below a specified speed, or when the compressor operates intermittently, it can switch from the waste heat recovery parallel mode to the waste heat recovery single mode to perform heating operation.

[0078] According to the vehicle air-conditioning device 1 of the present embodiment, when the operating condition during heating operation is a state where refrigerant may accumulate in the outdoor heat exchanger 7, it switches from the waste heat recovery parallel mode to the waste heat recovery single mode to perform heating operation. In this way, by temporarily stopping the circulation of the refrigerant to the outdoor heat exchanger 7, it is possible to avoid a state where refrigerant may accumulate in the outdoor heat exchanger 7. Moreover, during this period, it is possible to restore the discharged refrigerant pressure value PXO of the outdoor heat exchanger 7 and the suction refrigerant pressure value PS of the compressor 2 to a desired state. Thereby, it is possible to suppress a decrease in heating performance, a decrease in the durability of the compressor or a failure, and a false detection of refrigerant shortage.

[0079] The embodiments of the present invention have been described in detail with reference to the drawings above, but the specific structure is not limited to the above embodiments, and design changes and the like within the scope not departing from the gist of the present invention are also included in the present invention.

[0080] Description of Reference Numerals

[0081] 1: Vehicle air conditioning device, 2: Compressor, 4: Radiator, 6: Outdoor expansion valve, 7: Outdoor heat exchanger, 8: Indoor expansion valve, 9: Heat absorber, 32: Air conditioning controller (control device), 44: Suction temperature sensor, 54: Outdoor heat exchanger temperature sensor, 56: Outdoor heat exchanger pressure sensor, 61: Equipment temperature adjustment circuit, 63: Second circulation pump, 64: Cooling heat exchanger (refrigerant and heat medium heat exchanger), 65: Motor unit.

Claims

1. An air conditioning device for a vehicle, characterized in that Comprising: A refrigerant circuit including a compressor that compresses refrigerant, a heating unit that heats supply air supplied to an air-conditioning target space, and an outdoor heat exchanger that absorbs heat of the refrigerant; An equipment temperature adjustment circuit including a heat exchanger for a temperature-controlled object that uses the refrigerant to adjust the temperature of a temperature-controlled object mounted on a vehicle; and A control device that controls the refrigerant circuit and the equipment temperature adjustment circuit, The control device, during a heating operation for heating the interior of the vehicle using the heating unit, at least has: A temperature-controlled object heat absorption heating mode in which the refrigerant discharged from the compressor and dissipated heat in the heating unit absorbs heat in the heat exchanger for the temperature-controlled object; And A combined heating mode in which the refrigerant discharged from the compressor and dissipated heat in the heating unit absorbs heat in the outdoor heat exchanger and the heat exchanger for the temperature-controlled object, The control device performs control so that during a heating operation based on the combined heating mode, when determining an operating state in which the refrigerant may accumulate in the outdoor heat exchanger, it switches to the temperature-controlled object heat absorption heating mode to perform the heating operation.

2. The vehicle air-conditioning device according to claim 1, wherein When a state where the discharged refrigerant pressure value of the outdoor heat exchanger is less than the suction refrigerant pressure value of the compressor continues for a specified time or more, the control device determines that it is an operating state in which the refrigerant may accumulate in the outdoor heat exchanger, and switches from the combined heating mode to the temperature-controlled object heat absorption heating mode to perform the heating operation.

3. The vehicle air-conditioning device according to claim 2, characterized in that, The discharged refrigerant pressure value is a value calculated using the discharged refrigerant temperature of the outdoor heat exchanger and the refrigerant saturation temperature.

4. The vehicle air-conditioning device according to claim 2 or 3, characterized in that, The suction refrigerant pressure value is a value calculated using the suction refrigerant temperature of the compressor and the refrigerant saturation temperature.

5. The vehicle air-conditioning device according to claim 1, wherein When a state where the discharged refrigerant temperature of the outdoor heat exchanger is less than the suction refrigerant temperature of the compressor continues for a specified time or more, the control device determines that it is an operating state in which the refrigerant may accumulate in the outdoor heat exchanger, and switches from the combined heating mode to the temperature-controlled object heat absorption heating mode to perform the heating operation.

6. The vehicle air-conditioning device according to claim 5, wherein The discharged refrigerant temperature is a value calculated using the discharged refrigerant pressure value of the outdoor heat exchanger and the refrigerant saturation temperature.

7. The vehicle air conditioning device according to claim 5 or 6, characterized in that, The suction refrigerant temperature is a value calculated using the suction refrigerant pressure value of the compressor and the refrigerant saturation temperature.

8. The vehicle air conditioning device according to claim 1, characterized in that, When the compressor operates at a specified speed or less, or when the compressor operates intermittently, the control device determines that it is an operating state in which the refrigerant may accumulate in the outdoor heat exchanger, and switches from the combined heating mode to the temperature-controlled object heat absorption heating mode to perform the heating operation.

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