JP2012076589A - Air conditioner for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle air conditioner for removing frost in a short period of time even though heating and defrosting are simultaneously performed.SOLUTION: The air conditioner for the vehicle 10A has: a heat pump circuit 2 including a compressor 11, a switching means 12A, an outdoor heat exchanger 13, an expansion mechanism 15, and an indoor heat exchanger 16; and a bypass passage 3 for bypassing the outdoor heat exchanger 13. The switching means 12A switches a flow direction of a coolant to a first direction (arrow C) during cooling operation, and switches to a second direction (arrow H) during heating operation. A heating device 14 heating the coolant up to an overheated state is arranged between the expansion mechanism 15 and the outdoor heat exchanger 13. The bypass passage 3 is branched from the heat pump circuit 2 between the heating device 14 and the outdoor heat exchanger 13. The bypass passage 3 is provided with a first flow amount adjusting valve 31, and the heat pump circuit 2 is provided with a second flow amount adjusting valve 32.

Description

  The present invention relates to a vehicle air conditioner that cools and heats a passenger compartment.

  Conventionally, for example, in a car equipped with a gasoline engine, a heat pump is used for cooling, while waste heat of the engine is used for heating. In recent years, hybrid vehicles with a small amount of engine waste heat and electric vehicles that cannot use engine waste heat have become widespread, and in response to this, vehicle air conditioners that use heat pumps for heating as well as cooling have become available. It has been developed. For example, Patent Document 1 discloses an air conditioner 100 that drives a compressor 111 by an engine 150 as shown in FIG.

  The air conditioner 100 includes a heat pump circuit 110 including a compressor 111, a four-way valve 112, an outdoor heat exchanger 113, an outdoor expansion valve 114, an indoor expansion valve 115, and an indoor heat exchanger 116. During the cooling operation, the refrigerant compressed by the compressor 111 is caused to flow in the direction of the dashed arrow C, the outdoor heat exchanger 113 functions as a condenser, and the indoor heat exchanger 116 functions as an evaporator. On the other hand, during the heating operation, the refrigerant compressed by the compressor 111 is caused to flow in the direction of the solid line arrow H, the indoor heat exchanger 116 functions as a condenser, and the outdoor heat exchanger 113 functions as an evaporator.

  Further, the heat pump circuit 110 is provided with a first heater 121 and a second heater 122 in order to supplement external heat absorption when the outside air temperature is low. The first heater 121 is a heat exchanger that radiates water heated by the burner unit 160, and is disposed between the indoor expansion valve 115 and the outdoor expansion valve 114. The second heater 122 is a heat exchanger that dissipates the water that has cooled the engine 150, and is disposed between the four-way valve 112 and the suction port of the compressor 111.

  Further, the air conditioner 100 includes a first bypass path 130 and a second bypass path 140 as a configuration for performing a defrosting operation for removing frost attached to the outdoor heat exchanger 113. The first bypass 130 branches from the heat pump circuit 110 between the discharge port of the compressor 111 and the four-way valve 112 and is connected to the heat pump circuit 110 between the outdoor expansion valve 114 and the outdoor heat exchanger 113. The second bypass path 140 branches from the heat pump circuit 110 between the first heater 121 and the outdoor expansion valve 114 and is connected to the heat pump circuit 110 between the four-way valve 112 and the second heater 122. The first bypass passage 130 is provided with a control valve 131, and the second bypass passage 140 is provided with an on-off valve 141.

  In Patent Document 1, when it is determined that defrosting of the outdoor heat exchanger 113 is necessary during the heating operation, the on-off valve 141 is opened, the outdoor expansion valve 114 is closed, and the control valve 131 is further opened. As shown by solid arrows D1 to D5, the refrigerant flows and heating and defrosting are performed simultaneously.

JP 2002-106997 A

  However, in the configuration shown in FIG. 9, the expansion valve is not provided in the route from the discharge port to the suction port of the compressor 111 through the first bypass 130, and the control valve 131 is a simple flow rate adjustment valve. In the first place, the refrigeration cycle is not established. Even if the control valve 131 is an expansion valve, the heat absorbed by the first heater 121 and the second heater 122 is not directly transmitted to the outdoor heat exchanger 113, and it takes a long time to defrost. Become.

  In view of such circumstances, an object of the present invention is to provide a vehicle air conditioner that can perform defrosting in a short time while simultaneously performing heating and defrosting.

  In order to solve the above-described problems, the present invention provides a vehicle air conditioner that cools and heats a vehicle interior, the compressor compressing the refrigerant, and the outdoor heat performing heat exchange between the air outside the vehicle interior and the refrigerant. An exchanger, an expansion mechanism that expands the refrigerant, and a heat pump circuit that is disposed in the duct and includes an indoor heat exchanger that exchanges heat between the air sent to the vehicle interior by the blower and the refrigerant, and the refrigerant that flows through the heat pump circuit The flow direction of the refrigerant is switched to a first direction in which the refrigerant discharged from the compressor during the cooling operation passes through the outdoor heat exchanger, the expansion mechanism, and the indoor heat exchanger in this order and returns to the compressor. Switching means for switching to a second direction in which the refrigerant discharged from the compressor during operation passes through the indoor heat exchanger, the expansion mechanism, and the outdoor heat exchanger in this order and returns to the compressor A heater disposed between the expansion mechanism and the outdoor heat exchanger and capable of heating the refrigerant flowing through the heat pump circuit to an overheated state; and a heater between the heater and the outdoor heat exchanger in the heat pump circuit. A second outdoor flow path between the outdoor heat exchanger and the switching means in the heat pump circuit, or a suction-side flow path between the switching means and the suction port of the compressor; A second flow rate provided on the outdoor heat exchanger side than a position where the bypass route branches in the first outdoor flow path. An air conditioner for a vehicle provided with a regulating valve is provided.

  According to said structure, since the heater which can heat a refrigerant | coolant to an overheated state is provided, this heater can be functioned as an evaporator. For this reason, when frost adheres to the outdoor heat exchanger, heating and defrosting can be performed simultaneously by heating the refrigerant with the heater and flowing the overheated refrigerant to the bypass path and guiding it to the outdoor heat exchanger. it can. In addition, since heat is applied to the refrigerant from the heater, defrosting is performed by the high-temperature refrigerant at a low pressure, so that the defrosting can be performed in a short time.

The block diagram of the vehicle air conditioner which concerns on 1st Embodiment of this invention. (A) is a figure explaining the adjustment method of a 1st and 2nd flow regulating valve, (b) is a graph which shows the ratio of the refrigerant | coolant amount which flows into an outdoor heat exchanger when adjusted in that way (A) is a Mollier diagram during normal heating operation, (b) is a Mollier diagram during heating defrosting operation. The block diagram of the vehicle air conditioner which concerns on 2nd Embodiment of this invention. The block diagram of the vehicle air conditioner of the modification of 2nd Embodiment The block diagram of the vehicle air conditioner which concerns on 3rd Embodiment of this invention. The block diagram of the vehicle air conditioner of the modification of 3rd Embodiment (A) and (b) are block diagrams of alternative switching means Configuration diagram of conventional vehicle air conditioner

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a configuration diagram of a vehicle air conditioner 10A according to the first embodiment of the present invention. This vehicle air conditioner 10A cools and heats a vehicle interior (not shown), and includes a heat pump circuit 2 that circulates refrigerant, a bypass passage 3 that bypasses an outdoor heat exchanger 13 described later, and a control device 6. And. As the refrigerant, R134a, R410A, HFO-1234yf , HFO-1234ze, in addition to such CO _2, other HFC system, HC-based and available.

  The heat pump circuit 2 includes a compressor 11, a four-way valve 12 </ b> A, an outdoor heat exchanger 13, an expansion valve 15, and an indoor heat exchanger 16. The four-way valve 12A functions as the switching means of the present invention, and the flow direction of the refrigerant flowing through the heat pump circuit 2 is switched to the first direction indicated by the dashed arrow C during the cooling operation, and is indicated by the solid arrow H during the heating operation. Switch to the second direction. The first direction is a direction in which the refrigerant discharged from the compressor 11 passes through the outdoor heat exchanger 13, the expansion valve 15 and the indoor heat exchanger 16 in this order and returns to the compressor 11, and the second direction is a compression direction. The refrigerant discharged from the machine 11 passes through the indoor heat exchanger 16, the expansion valve 15 and the outdoor heat exchanger 13 in this order and returns to the compressor 11. Moreover, between the expansion valve 15 and the outdoor heat exchanger 13, the heater 14 which heats a refrigerant | coolant as needed is arrange | positioned. These devices 11 to 16 are cyclically connected by the first channel 21 to the seventh channel 27.

  The compressor 11 is driven by the electric motor 61, compresses the refrigerant sucked from the suction port 11a, and discharges it from the discharge port 11b. The electric motor 61 may be disposed inside the compressor 11 or may be disposed outside. The discharge port 11b of the compressor 11 is connected to the first port of the four-way valve 12A via a first flow path (corresponding to the discharge side flow path of the present invention) 21, and the suction port 11a of the compressor 11 is connected to the seventh port. It is connected to a fourth port of the four-way valve 12A via a flow path (corresponding to the suction-side flow path of the present invention) 27. The second port of the four-way valve 12A is connected to the outdoor heat exchanger 13 via a second flow path (corresponding to the second outdoor flow path of the present invention) 22, and the third port of the four-way valve 12A is It is connected to the indoor heat exchanger 16 via the sixth flow path 26. The seventh flow path 27 is provided with a pressure sensor 71 for detecting the pressure of the refrigerant sucked into the compressor 11 and a superheat degree sensor 81 for detecting the temperature of the refrigerant sucked into the compressor 11. It has been.

  The outdoor heat exchanger 13 is disposed, for example, at the front of an automobile, and performs heat exchange between the running of the vehicle and the outside air (air outside the passenger compartment) supplied by the fan 17 and the refrigerant. The outdoor heat exchanger 13 is connected to the heater 14 via a third flow path (corresponding to the first outdoor flow path of the present invention) 23.

  The heater 14 has a capability of heating the refrigerant flowing through the heat pump circuit 2 to an overheated state. In the present embodiment, a heat exchanger that performs heat exchange between the heat medium and the refrigerant is employed as the heater 14. Specifically, the heat medium circulated in the heat medium circuit 4 by the pump 41 is radiated by the heater 14 after being heated by the heat source 42.

  Note that the heat medium circuit 4 may be provided with a radiator that releases heat to the atmosphere in series or in parallel with the heater 14. The heat source 42 can be appropriately selected according to the driving means for running the vehicle. For example, a generator or an inverter can be used. The heat medium is, for example, water. However, the heater of this invention is not restricted to this, For example, you may employ | adopt the heater which directly heats refrigerant | coolants, such as a heater (for example, PTC heater). The heater 14 is connected to the expansion valve 15 via the fourth flow path 24.

  The expansion valve 15 expands the refrigerant and is an example of the expansion mechanism of the present invention. As the expansion mechanism of the present invention, a positive displacement expander that recovers power from the expanding refrigerant may be employed. The expansion valve 15 is connected to the indoor heat exchanger 16 via the fifth flow path 25.

  The indoor heat exchanger 16 is disposed in the duct 52 and performs heat exchange between the air sent to the vehicle interior by the blower 51 and the refrigerant. In the present embodiment, air in the passenger compartment is caused to flow through the duct 52 by the blower 51. That is, the air in the passenger compartment circulates through the duct 52. Note that the air that is blown into the duct 52 by the blower 51 does not necessarily need to be 100% of the vehicle interior air, and may include some outside air for vehicle interior ventilation, or may be all outside air. Hereinafter, as an example, it is assumed that the air taken into the duct 52 by the blower 51 and supplied to the indoor heat exchanger 16 is 100% of the vehicle interior air.

  As shown in FIG. 1, the blower 51 may be disposed on the inlet side of the duct 52, or may be disposed on the outlet side of the duct 52. A fan may be used as the blower 51.

  The bypass path 3 branches from the third flow path 23 of the heat pump circuit 2 and is connected to the second flow path 22. However, the bypass path 3 may be branched from the third flow path 23 and connected to the seventh flow path 27. A first flow rate adjustment valve 31 is provided in the bypass passage 3, and a second flow rate adjustment valve 32 is provided closer to the outdoor heat exchanger 13 than the position where the bypass passage 3 branches in the third flow passage 23. Yes. The first flow rate adjusting valve 31 is normally kept in a fully closed state, and is opened when defrosting of the outdoor heat exchanger 13 is necessary. The second flow rate adjustment valve 32 is normally kept fully open.

  In the present embodiment, an evaporator temperature sensor 82 is used as frosting detection means for determining that frost has adhered to the outdoor heat exchanger 13. The evaporator temperature sensor 82 is provided in the outdoor heat exchanger 13 so as to detect the surface temperature of the outdoor heat exchanger 13. However, the evaporator temperature sensor 82 is not necessarily provided in the outdoor heat exchanger 13, and is provided in the third flow path 23 so as to detect the temperature of the refrigerant flowing into the outdoor heat exchanger 13. Alternatively, it may be arranged on the leeward side of the outdoor heat exchanger 13 so as to detect the temperature of the air after coming into contact with the outdoor heat exchanger 13.

  Further, in the duct 52 described above, a blowing temperature sensor 83 that detects the temperature of the air blown into the vehicle interior through the duct 52 (blowing temperature) is provided.

  The control device 6 is connected to an operation panel (not shown) disposed in the vehicle compartment and the various sensors 71 and 81 to 83 described above. The control device 6 controls the four-way valve 12A to switch between the cooling operation and the heating operation, and the operation of the fan 17 and the blower 51, the operation of the pump 41, the rotational speed of the electric motor 61 that drives the compressor 11, The opening degree of the expansion valve 15 and the opening degree of the first flow rate adjustment valve 31 and the second flow rate adjustment valve 32 are controlled. Furthermore, when it is determined that frost has adhered to the outdoor heat exchanger 13 based on the detected value of the evaporator temperature sensor 82 during the heating operation, the control device 6 bypasses a part of the refrigerant superheated by the heater 14. A heating defrosting operation is performed in which the remainder flows to the outdoor heat exchanger 13 while flowing through the path 3.

  Next, operations during the cooling operation and the heating operation in the vehicle air conditioner 10A will be described.

  During the cooling operation, the high-temperature and high-pressure gas refrigerant compressed by the compressor 11 flows through the four-way valve 12A in the direction of the broken line arrow C. The gas refrigerant radiates heat to the outside air in the outdoor heat exchanger 13 and condenses. Thereafter, the liquid refrigerant is throttled by the expansion valve 15 to adiabatically expand to a low temperature and low pressure, and then is absorbed by the indoor heat exchanger 16 from the vehicle interior circulation air supplied by the blower 51 to evaporate, and the vehicle interior circulation. Cool the air. The refrigerant flowing out of the indoor heat exchanger 16 is again sucked into the compressor 11 through the four-way valve 12A.

  The control device 6 has a storage unit (not shown), and a saturation temperature corresponding to the refrigerant pressure is stored in the storage unit. The control device 6 reads the saturation temperature at the pressure detected by the pressure sensor 71 from the storage unit at appropriate times, compares the read saturation temperature with the refrigerant temperature detected by the superheat temperature sensor 81, and the temperature difference therebetween. The degree of opening of the expansion valve 15 is controlled so that becomes a predetermined superheat degree.

  The storage unit of the control device 6 does not necessarily need to store the saturation temperature corresponding to the refrigerant pressure. For example, using the fact that the refrigerant between the expansion valve 15 and the evaporator (the indoor heat exchanger 16 for cooling operation and the outdoor heat exchanger 13 for heating operation) is in a gas-liquid two-phase state, the saturation temperature May be obtained. In this case, a temperature sensor can be used instead of the pressure sensor 71.

  During the heating operation, the high-temperature and high-pressure gas refrigerant compressed by the compressor 11 flows in the direction of the solid arrow H through the four-way valve 12A. The gas refrigerant radiates and condenses the vehicle interior circulation air supplied by the blower 51 in the indoor heat exchanger 16 and heats the vehicle interior circulation air. Thereafter, the liquid refrigerant is throttled by the expansion valve 15 and adiabatically expanded to become a low temperature and low pressure, and then is absorbed by the outdoor heat exchanger 13 from the outside air and evaporated. The refrigerant flowing out of the outdoor heat exchanger 13 is again sucked into the compressor 11 through the four-way valve 12A (normal heating operation). The control of the opening degree of the expansion valve 15 during the heating operation is the same as during the cooling operation.

  Fig.3 (a) shows the Mollier diagram at the time of normal heating operation. The state of the refrigerant changes as indicated by point A to point D.

  When the outdoor heat exchanger 13 alone does not have enough heat absorption, or when it is desired to perform heating quickly such as at the time of start-up, the control device 6 operates the pump 41 so that both the heater 14 and the outdoor heat exchanger 13 operate. The refrigerant is evaporated (auxiliary heating / heating operation). Further, at an extremely low outside air temperature at which the outdoor heat exchanger 13 does not function, the control device 6 opens the first flow rate adjustment valve 31 and fully closes the second flow rate adjustment valve 32 so that the heater The refrigerant is evaporated only by 14 (internal heating operation).

  During normal heating operation or auxiliary heating heating operation, the temperature of the evaporator detected by the evaporator temperature sensor 82 is continuously below a freezing point for a certain time (for example, 30 minutes) (for example, −3 ° C. or −5 When the temperature becomes equal to or lower than (° C.), the control device 6 determines that frost has adhered to the outdoor heat exchanger 13 and shifts from the heating operation to the heating defrosting operation.

  Specifically, the control device 6 stops the operation of the fan 17 when the state where the evaporator temperature detected by the evaporator temperature sensor 82 is below the predetermined temperature is maintained for the predetermined time, and 1 Start to open the flow rate adjustment valve 31. Thereby, as shown by the solid line arrow D, the refrigerant also flows in the bypass passage 3.

  The control device 6 sets the opening degree of the first flow rate adjustment valve 31 and the opening degree of the second flow rate adjustment valve 32 so that the blowing temperature detected by the blowing temperature sensor 83 becomes a predetermined temperature (for example, 50 ° C.). adjust. In the present embodiment, the control device 6 keeps one of the first flow rate adjustment valve 31 and the second flow rate adjustment valve 32 in a fully open state during the heating defrosting operation.

  When the opening degree of the first flow rate adjustment valve 31 is gradually increased while the second flow rate adjustment valve 32 is kept fully open as shown in FIG. 2A, the outdoor heat exchanger is shown as shown in FIG. The ratio of the refrigerant amount flowing to 13 gradually decreases. Since the outdoor heat exchanger 13 generally has a structure in which the pressure loss is larger than that of the bypass passage 3, even if both the first flow rate adjustment valve 31 and the second flow rate adjustment valve 32 are fully opened, the outdoor heat The ratio of the amount of refrigerant flowing through the exchanger 13 is smaller than 0.5 (in FIG. 2B, 0.3 is shown as an example). After the first flow rate adjustment valve 31 is fully opened, if the opening degree of the second flow rate adjustment valve 32 is gradually reduced while the first flow rate adjustment valve 31 is kept in the fully open state, the first flow rate adjustment valve 31 flows to the outdoor heat exchanger 13. The ratio of the refrigerant amount gradually decreases to 0 with a gentler slope.

  For example, the controller 6 opens the first flow rate adjustment valve 31 to a certain degree of opening, or opens the first flow rate adjustment valve 31 until it is fully opened and closes the second flow rate adjustment valve 32 to a certain degree of opening. When the blowout temperature is higher than the predetermined temperature, the ratio of the amount of refrigerant flowing through the outdoor heat exchanger 13 is increased (corrected to the left in FIG. 2A), and when it is low, the amount of refrigerant flowing through the outdoor heat exchanger 13 is increased. May be reduced (corrected to the right in FIG. 2A).

  Further, at the same time as the control device 6 starts to open the first flow rate adjustment valve 31, the control device 6 causes the heater 14 that has not been functioning until now or performs auxiliary heating to function as an evaporator. Specifically, if the pump 41 is not operating, the control device 6 starts operating the pump 41. The control device 6 may increase the rotation speed of the pump 41 when the pump 41 is in operation. In addition, the control device 6 slightly increases the opening degree of the expansion valve 15 to reduce the high / low pressure difference of the refrigeration cycle.

  FIG.3 (b) shows the Mollier diagram at the time of heating defrost operation. FIG. 3B illustrates a state in which the second flow rate adjustment valve 32 is fully opened and the first flow rate adjustment valve 31 is at a predetermined opening. The refrigerant (point D) that has passed through the expansion valve 15 is overheated by the heater 14 (point E). A part of the overheated refrigerant flows through the bypass passage 3 and is slightly decompressed by the first flow rate adjusting valve 31 (point F). On the other hand, the remainder of the overheated refrigerant flows into the outdoor heat exchanger 13, where it dissipates heat and melts frost adhering to the outdoor heat exchanger 13 (point G). Thereafter, these refrigerants merge (point A) and are sucked into the compressor 11 again.

  As shown in FIG. 3B, the specific enthalpy difference between the inlet (point B) and the outlet (point C) of the indoor heat exchanger 16 is reduced during the heating defrosting operation. It is preferable to increase the circulation amount of the refrigerant by increasing the number of rotations of the electric motor 61 that drives the compressor 11 when the operation is shifted to the heating defrosting operation.

  In addition, it is preferable to reduce the temperature of the air blown out from the duct 52 by reducing the air volume of the blower 51 during the heating defrosting operation.

  As described above, in the vehicle air conditioner 10A according to the present embodiment, when it is determined that defrosting of the outdoor heat exchanger 13 is necessary, the heater 14 superheats the refrigerant, and bypasses the overheated refrigerant. 3 and led to the outdoor heat exchanger 13. Thereby, heating and defrosting can be performed simultaneously. And since heat is given to a refrigerant | coolant from the heater 14, defrosting is performed by the high temperature refrigerant | coolant, although it is low pressure, Therefore It becomes possible to perform defrosting in a short time.

  Furthermore, in this embodiment, since either one of the 1st flow regulating valve 31 and the 2nd flow regulating valve 32 is maintained in a full open state during heating defrosting operation, pressure loss can be restrained small.

  In order to perform efficient defrosting, it is necessary to distribute a sufficient amount of refrigerant to the outdoor heat exchanger 13, but if the superheated refrigerant is allowed to flow to the outdoor heat exchanger 13 that is below freezing point, the condensation temperature And the temperature of the outdoor heat exchanger 13 is so large that the refrigerant is liquefied vigorously. On the other hand, in order to prevent liquid compression of the compressor 11, it is necessary to operate the refrigerant that returns to the compressor 11 in an overheated state. For this reason, in addition to the control of the first flow rate adjustment valve 31 and the second flow rate adjustment valve 32 described above, superheat degree control by the opening degree of the expansion valve 15 is required.

  Also from the viewpoint of heating, it is necessary to adjust the blowing temperature to a predetermined temperature (for example, 50 ° C.) and to operate the refrigerant returning to the compressor 11 in an overheated state.

  For this reason, by adjusting the opening degree of the first flow rate adjusting valve 31 and the second flow rate adjusting valve 32 using the blowing temperature sensor 83 and the superheat degree control by the opening degree of the expansion valve 15, the interior of the vehicle compartment is also obtained during the heating defrosting operation. Can be supplied with air at a suitable temperature.

<Modification>
In the said embodiment, although the evaporator temperature sensor 82 was used as a detection means for frost formation, the detection means for frost formation of this invention is not restricted to this. For example, a refrigerant temperature sensor for detecting the temperature of the refrigerant flowing out of the outdoor heat exchanger 13 is provided on the outdoor heat exchanger 13 side of the second flow path 22 from the position where the bypass path 3 is connected, and the refrigerant temperature sensor is attached. You may use as a detection means for frost. When frost adheres to the outdoor heat exchanger 13, air cannot pass through the outdoor heat exchanger 13 and the amount of heat exchange between the air and the refrigerant decreases, so the temperature of the refrigerant flowing out of the outdoor heat exchanger 13 is the outside air temperature. It can be determined that frost has adhered to the outdoor heat exchanger 13 when the temperature becomes lower than the predetermined temperature.

  Alternatively, when the above phenomenon occurs, the ventilation resistance of the outdoor heat exchanger 13 increases due to frost formation, and the input to the fan 17 increases, so that when the drive current of the fan 17 becomes a certain value or more. It can also be determined that frost has adhered to the outdoor heat exchanger 13.

  Alternatively, a condenser temperature sensor that detects the temperature of the indoor heat exchanger 16 and a vehicle interior temperature sensor that detects the temperature of the vehicle interior are provided, and frost is generated in the outdoor heat exchanger 13 from the temperature difference between the detected values of these temperature sensors. You may determine with having adhered.

  Further, when defrosting is prioritized over heating, the rapid defrosting operation may be performed by causing the refrigerant to flow in the direction of the broken line arrow C without operating the fan 17 and the blower 51. Alternatively, the amount of heat used for defrosting may be further increased by operating the pump 41 during the rapid defrosting operation and heating the refrigerant radiated by the outdoor heat exchanger 13 with the heater 14. However, these operations cannot be performed continuously with the heating operation because the refrigerant needs to flow through the heat pump circuit 2 in the opposite direction to the heating operation. On the other hand, in the heating defrosting operation as in the above embodiment, since the refrigerant flows in the heat pump circuit 2 in the same direction as the heating operation, the defrosting can be started immediately from the heating operation.

In the said embodiment, the opening degree of the 1st flow regulating valve 31 and the 2nd flow regulating valve 32 is adjusted so that blowing temperature may become predetermined | prescribed temperature. However, the adjustment method of the opening degree of the 1st flow regulating valve 31 and the 2nd flow regulating valve 32 is not restricted to this. As another adjustment method, there is a method of determining the ratio r of the amount of refrigerant flowing into the outdoor heat exchanger 13 from the outside air temperature Tair (° C.) and the heating continuous time t (sec). The ratio r can be calculated by the following equation, for example.
r = (10−Tair) / 40 × t / 30
(0.1 <r <0.6, −10 <Tair <10, 10 <t <60)

  Furthermore, it is not always necessary to adjust the opening degree of the first flow rate adjustment valve 31 and the second flow rate adjustment valve 32 while keeping either one of them fully open, and both opening degrees are simultaneously adjusted to a predetermined opening degree. It is also possible.

(Second Embodiment)
FIG. 4 is a configuration diagram of a vehicle air conditioner 10B according to the second embodiment of the present invention. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. This is the same in the third embodiment described later.

  In the present embodiment, the first flow passage 21 is provided with the auxiliary heat exchanger 18 that performs heat exchange between the air sent to the vehicle interior by the blower 51 and the refrigerant. The auxiliary heat exchanger 18 is disposed in the duct 52 on the leeward side of the indoor heat exchanger 16. The other configuration of the vehicle air conditioner 10B is the same as that of the vehicle air conditioner 10A of the first embodiment.

  Specifically, in the sub indoor heat exchanger 18, a first air path that passes through the sub indoor heat exchanger 18 and a second air path that does not pass through the sub indoor heat exchanger 18 form a layer in the duct 52. Are arranged as follows. In order to realize this, for example, the indoor heat exchanger 16 is exposed from the side of the sub-indoor heat exchanger 18 to the outlet side of the duct 52, in other words, the sub-indoor heat is placed beside the sub-indoor heat exchanger 18. The sub-indoor heat exchanger 18 may be arranged near the wall surface of the duct 52 so that a certain space through which air that bypasses the exchanger 18 flows is secured. Alternatively, a part of the duct 52 surrounding the sub-indoor heat exchanger 18 may be inflated, and air that bypasses the sub-indoor heat exchanger 18 may be allowed to flow through the inflated portion.

  In the present embodiment, the partition plate that partitions the first air path and the second air path in the duct 52, and the ratio of the air volume flowing through the first air path and the air volume flowing through the second air path are set. It is preferable that a damper to be adjusted is provided.

  In such a configuration, the vehicle interior circulating air heated by the indoor heat exchanger 16 can be further heated by the sub-indoor heat exchanger 18, so that an effect of increasing the heating capacity can be obtained. Needless to say, the vehicle air conditioner 10B can achieve the same effects as the vehicle air conditioner 10A of the first embodiment.

<Modification>
By the way, in the vehicle air conditioner 10B of the above embodiment, since heat is always released from the sub-indoor heat exchanger 18, the indoor heat exchanger 16 is used as an evaporator to dehumidify the circulating air in the vehicle interior while heating. Need to work. In order to realize this, the refrigerant must flow in the direction indicated by the broken line arrow C. However, since heat is also released from the outdoor heat exchanger 13 in this manner, heat pump heating using the heat of the outside air cannot be performed.

  On the other hand, like the vehicle air conditioner 10C of the modification shown in FIG. 5, the second expansion valve 19 is provided in the second flow path 22 and the on-off valve bypasses the expansion valve 15 in the heat pump circuit 2. A first selection path 91 with 92 and a second selection path 93 with an on-off valve 94 that bypasses the second expansion valve 19 may be provided. In this configuration, if the on-off valve 92 is opened, the expansion valve 15 is fully closed, the on-off valve 94 is closed, and the refrigerant is allowed to flow in the direction of the broken line arrow C, the vehicle interior circulation air is dehumidified while heating. Can do.

(Third embodiment)
FIG. 6 is a configuration diagram of a vehicle air conditioner 10D according to the third embodiment of the present invention. In the present embodiment, the seventh flow path 27 is provided with the auxiliary heat exchanger 18 that performs heat exchange between the air sent to the vehicle interior by the blower 51 and the refrigerant. The auxiliary heat exchanger 18 is disposed in the duct 52 on the windward side of the indoor heat exchanger 16. The remaining configuration of the vehicle air conditioner 10D is the same as that of the vehicle air conditioner 10A of the first embodiment.

  Specifically, in the sub indoor heat exchanger 18, a first air path that passes through the sub indoor heat exchanger 18 and a second air path that does not pass through the sub indoor heat exchanger 18 form a layer in the duct 52. Are arranged as follows. In order to realize this, for example, the indoor heat exchanger 16 is exposed from the side of the sub-indoor heat exchanger 18 to the inlet side of the duct 52, in other words, the sub-indoor heat is located beside the sub-indoor heat exchanger 18. The sub-indoor heat exchanger 18 may be arranged near the wall surface of the duct 52 so that a certain space through which air that bypasses the exchanger 18 flows is secured. Alternatively, a part of the duct 52 surrounding the sub-indoor heat exchanger 18 may be inflated, and air that bypasses the sub-indoor heat exchanger 18 may be allowed to flow through the inflated portion.

  In the present embodiment, the partition plate that partitions the first air path and the second air path in the duct 52, and the ratio of the air volume flowing through the first air path and the air volume flowing through the second air path are set. It is preferable that a damper to be adjusted is provided.

  In such a configuration, the circulating air in the vehicle interior can be cooled by the two heat exchangers 16 and 18 during the cooling operation, and the circulating air in the vehicle interior can be dehumidified by the auxiliary indoor heat exchanger 18 during the heating operation. Needless to say, the vehicle air conditioner 10B can achieve the same effects as the vehicle air conditioner 10A of the first embodiment.

<Modification>
In the embodiment, the first air passage through which the auxiliary indoor heat exchanger 18 passes through the auxiliary indoor heat exchanger 18 in the duct 52 and the second air passage that does not pass through the auxiliary indoor heat exchanger 18 form a layer. Are arranged as follows. On the other hand, like the vehicle air conditioner 10E of the modification shown in FIG. 7, only the indoor heat exchanger 16 is connected to the third air passage through the indoor heat exchanger 16 in the duct 52 and the indoor heat exchanger. It is also possible to arrange so that the fourth air passage that does not pass through 16 forms a layer.

  Or although illustration is abbreviate | omitted, both the sub indoor heat exchanger 18 and the indoor heat exchanger 16 have a 1st air path and a 2nd air path, and a 3rd air path and a 4th air path. It is also possible to arrange them in layers.

(Other embodiments)
In each of the above embodiments, the four-way valve 12A is used as the switching means, but the switching means of the present invention is not limited to this. For example, in the switching means, as shown in FIG. 8 (a), two three-way valves 121 connected to the first flow path 21 and the seventh flow path 27 are connected in a loop shape by a pair of pipes 122. A circuit 12B in which the second flow path 22 and the sixth flow path 26 are connected to the pipe 122 may be used. Alternatively, the switching means may be a so-called bridge circuit 12C as shown in FIG.

  The vehicle air conditioner of the present invention can effectively utilize exhaust heat, and is particularly useful for non-combustion vehicles such as electric vehicles and fuel cell vehicles.

10A to 10E Vehicle air conditioner 11 Compressor 11a Suction port 11b Discharge port 12A Four-way valve (switching means)
12B circuit (switching means)
12C Bridge circuit (switching means)
DESCRIPTION OF SYMBOLS 13 Outdoor heat exchanger 14 Heater 15 Expansion mechanism 16 Indoor heat exchanger 18 Sub indoor heat exchanger 2 Heat pump circuit 21 1st flow path (discharge side flow path)
22 Second channel (second outdoor channel)
23 Third channel (first outdoor channel)
27 Seventh channel (suction side channel)
DESCRIPTION OF SYMBOLS 3 Bypass path 31 1st flow regulating valve 32 2nd flow regulating valve 51 Blower 52 Duct 6 Control apparatus 82 Evaporator temperature sensor (detection means for frost formation)
83 Blowout temperature sensor

Claims (8)

A vehicle air conditioner for cooling and heating a passenger compartment,
A compressor that compresses the refrigerant, an outdoor heat exchanger that exchanges heat between the air outside the passenger compartment and the refrigerant, an expansion mechanism that expands the refrigerant, and an air and refrigerant that are arranged in a duct and are sent into the passenger compartment by a blower A heat pump circuit including an indoor heat exchanger for exchanging heat with
The flow direction of the refrigerant flowing through the heat pump circuit is such that the refrigerant discharged from the compressor during the cooling operation passes through the outdoor heat exchanger, the expansion mechanism, and the indoor heat exchanger in this order and returns to the compressor. Switching means for switching to one direction and switching to a second direction in which refrigerant discharged from the compressor passes through the indoor heat exchanger, the expansion mechanism and the outdoor heat exchanger in this order and returns to the compressor during heating operation When,
A heater that is disposed between the expansion mechanism and the outdoor heat exchanger and that can heat the refrigerant flowing through the heat pump circuit to an overheated state;
A second outdoor flow path between the outdoor heat exchanger and the switching means in the heat pump circuit, branched from a first outdoor flow path between the heater and the outdoor heat exchanger in the heat pump circuit; A bypass path connected to a suction-side flow path between the switching means and the suction port of the compressor;
A first flow rate adjusting valve provided in the bypass path;
A second flow rate adjustment valve provided on the outdoor heat exchanger side from a position where the bypass path branches in the first outdoor flow path;
A vehicle air conditioner. Frosting detection means for determining that frost has adhered to the outdoor heat exchanger;
When it is determined that frost has adhered to the outdoor heat exchanger based on the detection value of the frosting detection means during heating operation, a part of the refrigerant superheated by the heater flows through the bypass passage and remains A control device that performs a heating defrosting operation that guides the outdoor heat exchanger to the outdoor heat exchanger;
The vehicle air conditioner according to claim 1, further comprising: A blowout temperature sensor for detecting a temperature of air blown into the vehicle compartment through the duct;
The said control apparatus adjusts the opening degree of the said 1st flow regulating valve and the opening degree of the said 2nd flow regulating valve so that the temperature detected by the said blowing temperature sensor may become predetermined | prescribed temperature. Vehicle air conditioner.   4. The vehicle air conditioner according to claim 3, wherein the control device keeps one of the first flow rate adjustment valve and the second flow rate adjustment valve in a fully open state during the heating defrosting operation. The compressor is driven by an electric motor,
The said control apparatus is a vehicle air conditioner as described in any one of Claims 2-4 which enlarges the rotation speed of the said electric motor, when it transfers to the said heating defrost operation from the said heating operation. In the discharge side flow path between the discharge port of the compressor and the switching means in the heat pump circuit, a sub-indoor heat exchanger that performs heat exchange between the air sent to the vehicle interior by the blower and the refrigerant is provided. And
The vehicular air conditioner according to any one of claims 1 to 5, wherein the sub-indoor heat exchanger is disposed on the leeward side of the indoor heat exchanger in the duct. The suction side flow path is provided with a sub-indoor heat exchanger that performs heat exchange between the air sent to the vehicle interior by the blower and the refrigerant,
The vehicular air conditioner according to any one of claims 1 to 5, wherein the sub-indoor heat exchanger is disposed on the windward side of the indoor heat exchanger in the duct.   The sub-indoor heat exchanger is disposed in the duct so that a first air passage that passes through the sub-indoor heat exchanger and a second air passage that does not pass through the sub-indoor heat exchanger form a layer. The vehicle air conditioner according to claim 6 or 7.

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