JP2012126280A - Vehicle air conditioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle air conditioning device that can maintain a heater operation without increasing an input of a compressor even when an outdoor heat exchanger is frozen.SOLUTION: There are provided: the vapor compression refrigeration cycle 2, which includes a compressor 3, an indoor capacitor 4, an outdoor heat exchanger 6, and a ventilation heat recovery evaporator 13, and can execute an outside air heat-absorbing heater operation that absorbs heat from air to a refrigerant by the outdoor heat exchanger 6 and releases the heat of the refrigerant to the air by the indoor capacitor 4, and an exhaust air heat-absorbing heater operation that absorbs heat from air to a refrigerant by the ventilation heat recovery evaporator 13 and releasing the heat of the refrigerant to the air by the indoor capacitor 4; and the control means 30, which switches these operations from the outside air heat-absorbing heater operation to the exhaust air heat-absorbing heater operation when the outdoor heat exchanger 6 freezes during the outside air heat-absorbing heater operation.

Description

  The present invention relates to a vehicle air conditioner that has a vapor compression refrigeration cycle and that heats heat from air outside the vehicle compartment to heat the vehicle interior.

  For example, in an electric vehicle, the heat from the drive source can hardly be used for heating the passenger compartment. Therefore, various vehicle air conditioners that use a vapor compression refrigeration cycle, absorb heat from the air outside the passenger compartment with a refrigerant circulating in the cycle, and use the heat for heating the passenger compartment (for example, patents). Reference 1 and Patent Reference 2).

  However, the outdoor heat exchanger that exchanges heat with the air outside the passenger compartment may freeze (icing), and if the outdoor heat exchanger freezes, the heat exchange performance deteriorates, and the desired heating operation cannot be maintained. For this reason, in the vehicle air conditioner disclosed in Patent Document 1, a hot gas bypass passage for bypassing the indoor condenser is attached to the vapor compression refrigeration cycle, and high-temperature and high-pressure refrigerant compressed by the compressor flows into the indoor condenser and hot gas. It also flows to the outdoor heat exchanger via the bypass. Since the high-temperature refrigerant flows through the outdoor heat exchanger, freezing is eliminated. Further, the air supplied to the vehicle interior is heated by the indoor condenser. Thereby, even if an outdoor heat exchanger freezes, heating operation can be maintained.

  In Patent Document 2, heating operation and dehumidifying operation can be performed, and in the dehumidifying operation, the rotation speed of the compressor can be controlled to adjust the blowing temperature of the conditioned air. There is no disclosure of a technique that can maintain heating operation even if the vessel is frozen.

JP 2000-203249 A (Patent No. 4341093) JP 10-287125 A (Patent No. 3799732)

  However, in the conventional vehicle air conditioner, since the refrigerant has to flow through the indoor condenser and the outdoor heat exchanger during the freeze-free operation of the outdoor heat exchanger, the rotation speed of the compressor is reduced compared to the normal heating operation. There is a problem that it needs to be raised and requires a large amount of power. For example, in a vehicle that relies on a vehicle battery for the power of a compressor such as an electric vehicle, the cruising distance becomes short, which is not practical.

  Therefore, the present invention has been made to solve the above-described problems, and even when the outdoor heat exchanger freezes (is icing), the vehicle air that can maintain the heating operation without increasing the power of the compressor. It aims at providing a harmony device.

  The present invention relates to a compressor that compresses refrigerant, an indoor condenser that heats and exchanges heat between the refrigerant compressed by the compressor and air supplied to the passenger compartment, and the refrigerant and air outside the passenger compartment. An outdoor heat exchanger that exchanges heat with the refrigerant, and an evaporator for recovering ventilation heat that exchanges heat between the refrigerant and the air exhausted from the passenger compartment to the outside of the passenger compartment. Air is supplied to the refrigerant in the outdoor heat exchanger. An external heat absorption heating operation in which heat is absorbed more and the refrigerant is radiated to air by the indoor condenser, and an exhaust heat absorption heating operation in which the refrigerant is absorbed by the refrigerant by the ventilation heat recovery evaporator and is radiated to the refrigerant by the indoor condenser. When it is determined that the vapor compression refrigeration cycle, the freezing determination means for determining that the outdoor heat exchanger is frozen, and the freezing determination means are frozen, the heat absorption heating operation from the outside air is performed. Characterized in that a control means for switching the operation to.

  It is preferable to have a blower that blows air in the passenger compartment to the outside of the passenger compartment through the ventilation heat recovery evaporator.

  The vapor compression refrigeration cycle bypasses the outdoor heat exchanger and pressure adjusting means capable of adjusting the pressure of refrigerant supplied to the outdoor heat exchanger and the ventilation heat recovery evaporator, and the ventilation heat recovery evaporator includes And a first flow path switching means that can switch whether the refrigerant flows to the outdoor heat exchanger side or the ventilation heat recovery evaporator side, and in the outdoor heat absorption heating operation, The refrigerant compressed by the compressor is used as a refrigerant path that returns to the compressor through the indoor condenser, the pressure adjusting means, and the outdoor heat exchanger, and the refrigerant is depressurized by the pressure adjusting means, and the outdoor heat exchanger In the exhaust heat absorption heating operation, the refrigerant is made to absorb heat from the air, and the refrigerant compressed by the compressor is used as the indoor condenser, the pressure adjusting means, and the ventilation heat recovery evaporator. Through the refrigerant path back to the compressor, the refrigerant depressurized by the pressure regulating means, it is preferable to heat absorption from the air to the refrigerant in the ventilation heat recovery evaporator.

  The vapor compression refrigeration cycle is configured to exchange heat between the refrigerant and air supplied to the passenger compartment, to cool the air, and to reduce the pressure of the refrigerant supplied to the indoor evaporator, A bypass path for bypassing the indoor evaporator, and second flow path switching means capable of switching between flowing the refrigerant to the indoor evaporator side or the bypass path, and causing the refrigerant to absorb heat from the air by the indoor evaporator, Cooling reheat operation can be performed in which heat is released to the refrigerant by the condenser and the outdoor heat exchanger. In the cooling reheat operation, the refrigerant compressed by the compressor is used as the indoor condenser, the pressure adjusting unit, and the outdoor heat exchange. And a refrigerant path that returns to the compressor through the indoor evaporator, the refrigerant, and the refrigerant by the pressure adjusting means. Passed without decompression, it is preferable to heat radiation in the air to the refrigerant in the outdoor heat exchanger.

  An outdoor heat exchanger passing air temperature detecting means for detecting an air temperature that has passed through the outdoor heat exchanger; and a refrigerant temperature detecting means for detecting a refrigerant temperature on the outlet side of the outdoor heat exchanger; Means is freezing based on a difference between a passing air temperature of the outdoor heat exchanger detected by the outdoor heat exchanger passing air temperature detecting means and a refrigerant outlet temperature of the outdoor heat exchanger detected by the refrigerant temperature detecting means. Is preferably discriminated.

  During the exhaust heat absorption heating operation, it is preferable to introduce the air outside the passenger compartment into the indoor condenser.

  In addition to the indoor condenser, heating means for heating the air supplied to the vehicle interior, foot blowing temperature detection means for detecting the air temperature blown from the foot blowout port, and air temperature blown out from the defroster blowout port and the vent blowout port Defroster / vent outlet temperature detecting means for detecting, and the control means controls the heating amount of the heating means based on the detected temperatures of the foot outlet temperature detecting means and the defroster / vent outlet temperature detecting means. Is preferred.

  The outdoor heat exchanger has a plurality of tubes and a pair of tank portions provided on both ends of the plurality of tubes, a partition wall is provided in the tank portions, and a refrigerant flow path in the outdoor heat exchanger It is preferable that the partition wall located on the most downstream side is configured to be able to guide the refrigerant to the liquid reservoir and to pass the refrigerant with a small flow resistance.

  According to the present invention, when the outdoor heat exchanger freezes during the outdoor heat absorption heating operation in which the outdoor heat exchanger functions as an evaporator, the heating operation is continued by switching to the exhaust heat absorption heating operation in which the refrigerant absorbs heat in the ventilation heat recovery evaporator. In the outdoor air endothermic heating operation and the exhaust endothermic heating operation, since only the heat exchanger that performs the endothermic action is changed, it is not necessary to increase the power of the compressor to continue the heating operation. As described above, even when the outdoor heat exchanger is frozen (icing), the heating operation can be maintained without increasing the power of the compressor.

1 shows an embodiment of the present invention and is a configuration diagram of a vehicle air conditioner. FIG. 1 shows an embodiment of the present invention, (a) is a configuration diagram of an outdoor heat exchanger, (b) is a configuration diagram of a modified outdoor heat exchanger. It is a figure which shows one Embodiment of this invention and shows the refrigerant | coolant path | route at the time of exhaust heat absorption heating operation. It is a figure which shows one Embodiment of this invention and shows the refrigerant | coolant path | route at the time of an external air endothermic heating operation. It is a figure which shows one Embodiment of this invention and shows the refrigerant | coolant path | route at the time of a cooling reheat driving | operation. 1 is an operation flowchart of a vehicle air conditioner according to an embodiment of the present invention.

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

  As shown in FIG. 1, the vehicle air conditioner 1 includes a vapor compression refrigeration cycle 2. The vapor compression refrigeration cycle 2 includes a compressor 3 for compressing a refrigerant, an indoor condenser 4, a pressure adjusting means 5 arranged downstream of the indoor condenser 4, and an outdoor heat arranged downstream of the pressure adjusting means 5. The heat exchanger 6, the temperature type expansion valve 7 that is disposed downstream of the outdoor heat exchanger 6 and is a pressure reducing means for decompressing the refrigerant, the indoor evaporator 8 disposed downstream of the temperature type expansion valve 7, and the indoor evaporator 8 And an accumulator 9 arranged on the downstream side of these, and these are connected by respective refrigerant pipes 10.

  The compressor 3 is, for example, a vane type, and is turned on / off and the rotational speed is controlled by a command from the control means 30.

  The indoor condenser 4 is disposed in the air conditioning case 21 and downstream of the indoor evaporator 8. The indoor condenser 4 exchanges heat between the high-temperature and high-pressure refrigerant compressed by the compressor 3 and air passing through the air conditioning case 21 (air supplied to the vehicle interior). The indoor condenser 4 heats the air by the heat dissipation action of the refrigerant.

  The pressure adjusting means 5 includes an orifice 5a and a bypass passage 5c with an on-off valve 5b connected in parallel to the orifice 5a. By setting the on-off valve 5b to the open position, the refrigerant can flow as it is without reducing the pressure. By setting the on-off valve 5b to the closed position, the refrigerant can be depressurized and flowed through the orifice 5a. The on-off valve 5b is controlled by the control means 30.

  The outdoor heat exchanger 6 is disposed, for example, in the engine room. The outdoor heat exchanger 6 exchanges heat between the refrigerant that has passed through the indoor condenser 4 and the air outside the passenger compartment. The outdoor heat exchanger 6 functions as a condenser or functions as an evaporator according to the reduced pressure state of the pressure adjusting means 5. The internal configuration of the outdoor heat exchanger 6 will be described in detail below.

  The temperature type expansion valve 7 has a temperature sensing cylinder (not shown) attached to the outlet side of the indoor evaporator 8, and the refrigerant superheat degree (superheat) on the outlet side of the indoor evaporator 8 is maintained at a predetermined value. Adjust the valve opening automatically.

  The indoor evaporator 8 is disposed in the air conditioning case 21 and upstream of the indoor condenser 4. The indoor evaporator 8 exchanges heat between the refrigerant decompressed by the temperature type expansion valve 7 and the air passing through the air conditioning case 21 (air supplied to the vehicle interior). The indoor evaporator 8 cools and dehumidifies the air by the endothermic action of the refrigerant.

  The accumulator 9 temporarily stores surplus refrigerant among the refrigerant sent from the indoor evaporator 8 and sends only the gas refrigerant to the compressor 3.

  The air conditioning case 21 is provided with an outside air introduction port 22 for introducing air outside the vehicle interior and an inside air introduction port 23 for introducing air inside the vehicle interior. The outside air introduction port 22 and the inside air introduction port 23 are opened and closed by an intake door 24. The position of the intake door 24 is changed by the control means 30. A blower 25 is provided in the air conditioning case 21. The blower 25 sucks outside air or inside air into the air conditioning case 21 according to the position of the intake door 24. In the air conditioning case 21, a heater 26 and an air mix door 27 which are heating means disposed downstream of the indoor condenser 4 are provided. The air mix door 27 adjusts the air distribution ratio between the air that passes through the indoor condenser 4 and the heater 26 and the air that bypasses the air. The heater 26 is a heat source different from the vapor compression refrigeration cycle 2, and is constituted by, for example, a PTC heater. The heating amount of the heater 26 is controlled by the control means 30.

  A foot air outlet 28a, a defroster air outlet 28b, and a vent air outlet 28c are provided downstream of the heater 26 of the air conditioning case 21. Air-conditioned air is supplied into the passenger compartment from these outlets.

  In addition, the vapor compression refrigeration cycle 2 includes a draft branch 11 that bypasses the refrigerant compressed by the indoor condenser 4 without passing through the outdoor heat exchanger 6, an upstream end of the draft branch 11, and a refrigerant pipe 10. The first flow path switching valve 12 serving as the first flow path switching means provided at the connection point, the ventilation heat recovery evaporator 13 disposed in the drafter branch path 11, and the downstream of the ventilation heat recovery evaporator 13 And a non-return valve 19 arranged in the side drafter branch 11. The first flow path switching valve 12 switches whether the refrigerant is passed through the outdoor heat exchanger 6 or the ventilation heat recovery evaporator 13 (draft branch 11 for the drafter). The check valve 19 prevents the refrigerant from flowing back to the ventilation heat recovery evaporator 13 side when the refrigerant is circulated in the refrigerant path of the outdoor heat absorption heating operation or the cooling reheat operation.

  The evaporator 13 for recovering ventilation heat is disposed in an exhaust passage (draft passage) 29a that communicates between the vehicle interior and the exterior of the vehicle interior. A blower 29b is disposed in the exhaust passage 29a. By driving the blower 29b, the air in the passenger compartment is forcibly sucked into the exhaust passage 29a. The sucked air in the passenger compartment passes through the ventilation heat recovery evaporator 13 and is exhausted outside the passenger compartment. The blower 29b is controlled by the control means 30.

  Furthermore, the vapor compression refrigeration cycle 2 includes a bypass path 15 that bypasses the refrigerant without passing through the indoor evaporator 8, and a second flow path switching provided at a connection point between the upstream end of the bypass path 15 and the refrigerant pipe 10. And a second flow path switching valve 16 as means. The second flow path switching valve 16 switches whether the refrigerant is passed through the indoor evaporator 8 or the bypass path 15.

  The first flow path switching valve 12 and the second flow path switching valve 16 are each switched by the control means 30. Specifically, in the outdoor heat absorption heating operation, as shown in FIG. 4, the refrigerant compressed by the compressor 3 passes through the indoor condenser 4, the pressure adjusting means 5, the outdoor heat exchanger 6, and the bypass passage 15. The refrigerant path is switched back to 3. The pressure adjusting means 5 depressurizes the refrigerant, and the outdoor heat exchanger 6 functions as an evaporator. In the exhaust heat absorption heating operation, as shown in FIG. 3, the refrigerant compressed by the compressor 3 returns to the compressor 3 through the indoor condenser 4, the pressure adjusting means 5, the ventilation heat recovery evaporator 13, and the bypass 15. Switch to a route. The pressure adjusting means 5 depressurizes the refrigerant. In the cooling reheat operation, as shown in FIG. 5, the refrigerant compressed by the compressor 3 passes through the indoor condenser 4, the pressure adjusting means 5, the outdoor heat exchanger 6, the temperature expansion valve 7, and the indoor evaporator 8. The refrigerant path is switched back to 3. The pressure adjusting means 5 does not depressurize the refrigerant, and the outdoor heat exchanger 6 functions as a condenser.

  Further, the vehicle air conditioner 1 includes an outdoor heat exchanger passage air temperature detection sensor S1 that is an outdoor heat exchanger passage air temperature detection means that detects an air temperature that has passed through the outdoor heat exchanger 6, and an outdoor heat exchanger. A refrigerant temperature detection sensor S2 which is a refrigerant temperature detection means for detecting the refrigerant temperature on the outlet side of the outlet 6, an evaporator outlet air temperature detection sensor S3 which is an evaporator outlet air temperature detection means for detecting the air blowing temperature of the indoor evaporator 8, A foot blowing temperature detection sensor S4 which is a foot blowing temperature detecting means for detecting an air temperature blown from the foot blowing outlet 28a, and a defroster / vent blowing temperature detecting means for detecting an air temperature blown from the defroster blowing outlet 28b and the vent blowing outlet 28c. A certain defroster / vent outlet detection sensor S5 and an indoor temperature which is an indoor temperature detecting means for detecting the temperature in the passenger compartment Out and a sensor S6.

  The control means 30 is based on input data from the operation unit 31, detection data of various sensors S1 to S6, and the like, the compressor 3, the on-off valve 5b of the pressure adjusting means 5, the first flow path switching valve 12, the second flow. The path switching valve 16, the intake door 24, the blower 25, the heater 26, the air mix door 27, and the like are controlled. The control means 30 also serves as a freezing determination means for determining that the outdoor heat exchanger 6 has been frozen. The control means 30 inputs the outdoor heat exchanger passage air temperature detection sensor S1 and the refrigerant temperature detection sensor S2, and the difference between the air temperature that has passed through the outdoor heat exchanger 6 and the refrigerant temperature on the outlet side of the outdoor heat exchanger 6 Is determined to be frozen (icing) when the temperature difference exceeds a predetermined temperature difference (for example, 10 ° C.).

The operation unit 31 includes a heating switch SW1, a cooling switch SW2, an indoor temperature setting knob 32, and the like. A target temperature in the passenger compartment is set by the indoor temperature setting knob 32. The control means 30 executes the flowchart shown in FIG. 6 by turning on the heating switch SW1 and the cooling switch SW2. The contents of this flowchart will be described in the following operation location. Further, the control means 30 controls the heating operation or the like so that the temperature detected by the indoor temperature detection sensor S6 becomes the target temperature.
Next, a detailed configuration of the outdoor heat exchanger 6 will be described. As shown in FIG. 2A, the outdoor heat exchanger 6 includes a plurality of tubes 40 arranged in the horizontal direction at intervals, a radiating fin 41 arranged in a gap between adjacent tubes 40, and a plurality of tubes. A pair of tank portions 42 and 43 are provided on both ends of the tube 40. One tank portion 42 is provided with a refrigerant inlet 44 at its upper end side and a refrigerant outlet 45 at its lower end side. A liquid reservoir 46 is provided outside the other tank 43. The other tank portion 43 and the liquid reservoir portion 46 communicate with each other through a communication passage 47. In both tank parts 42 and 43, the partition walls 48 and 49 are each provided in one place. The partition wall 48 in one tank portion 42 completely partitions the tank portion 42. The partition wall 49 of the other tank portion 43 is located on the most downstream side in the refrigerant flow path in the outdoor heat exchanger 6 and is disposed so as not to partition the communication passage 47. That is, the partition wall 49 has a function of guiding the liquid refrigerant to the liquid reservoir 46 when the outdoor heat exchanger 6 functions as a condenser, but when the outdoor heat exchanger 6 functions as an evaporator, the vaporized refrigerant Is passed with a small passage resistance.

  Next, the operation of the vehicle air conditioner 1 will be described. As shown in FIG. 6, the control means 30 always checks whether either the heating switch SW1 or the cooling switch SW2 is turned on (steps ST1 to ST3). When the cooling switch SW2 is turned on (step ST1), the control means 30 executes a cooling reheat operation (step ST3). In the cooling reheat operation, as shown in FIG. 5, the first flow path switching valve 12 is switched so that the refrigerant flows to the outdoor heat exchanger 6 side, and the second flow path switching valve 16 is switched to flow the refrigerant to the indoor evaporator 8 side. . The on-off valve 5b of the pressure adjusting means 5 is in an open position that allows the refrigerant to pass therethrough without being depressurized.

  The refrigerant compressed by the compressor 3 includes the indoor condenser 4, the pressure adjusting means 5, the first flow path switching valve 12, the outdoor heat exchanger 6, the second flow path switching valve 16, the temperature type expansion valve 7, and the indoor evaporator 8. The refrigerant path through the accumulator 9 is circulated. The high-temperature and high-pressure refrigerant compressed by the compressor 3 radiates heat to the air through the indoor condenser 4 and the outdoor heat exchanger 6. The refrigerant, which has become a low temperature due to heat radiation and has been made a low pressure by the temperature type expansion valve 7, absorbs heat from the air by the indoor evaporator 8. Therefore, the air passing through the air conditioning case 21 is cooled by the indoor evaporator 8 and part or all of the air is reheated by the indoor condenser 4. Thereby, the cold air of desired temperature is produced.

  When the heating switch SW1 is turned on (step ST2), the control means 30 executes an outdoor air endothermic heating operation (step ST4). In the outdoor air endothermic heating operation, as shown in FIG. 4, the first flow path switching valve 12 switches so that the refrigerant flows to the outdoor heat exchanger 6 side and the second flow path switching valve 16 switches to the bypass path 15 side. It is done. The on-off valve 5b of the pressure adjusting means 5 is located at the closed position. The intake door 24 is switched to the outside air introduction side. The air mix door 27 is switched to a fully open position, for example. The refrigerant compressed by the compressor 3 circulates through the refrigerant path passing through the indoor condenser 4, the first flow path switching valve 12, the outdoor heat exchanger 6, the second flow path switching valve 16, the bypass path 15, and the accumulator 9. The high-temperature and high-pressure refrigerant compressed by the compressor 3 radiates heat to the air by the indoor condenser 4. The refrigerant having a low temperature by this heat radiation and having a low pressure by passing through the orifice 5 a of the pressure adjusting means 5 absorbs heat from the air in the outdoor heat exchanger 6. Therefore, the air passing through the air conditioning case 21 passes through the indoor evaporator 8 without being cooled and is heated by the indoor condenser 4. Thereby, the warm air of desired temperature is produced.

  When the heating capacity of the indoor condenser 4 is small, the heater 26 is operated to produce hot air at a desired temperature.

  In the outside air endothermic heating operation, air outside the passenger compartment with low humidity is introduced into the air conditioning case 21 (circulation of outside air), so that the occurrence of window fogging can be suppressed as much as possible.

  During the outdoor air endothermic heating operation, it is determined whether or not the outdoor heat exchanger 6 has been frozen (iced) every predetermined time (step ST5).

  If it is determined that the outdoor heat exchanger 6 is frozen, the outdoor air endothermic heating operation is switched to the exhaust endothermic heating operation (step ST6).

  In the exhaust heat absorption heating operation, as shown in FIG. 3, the first flow path switching valve 12 causes the refrigerant to flow to the ventilation heat recovery evaporator 13 side, and the second flow path switching valve 16 causes the refrigerant to flow to the bypass path 15 side. Can be switched. The on-off valve 5b of the pressure adjusting means 5 is located at the closed position. The intake door 24 is switched to the outside air introduction side. The air mix door 27 is switched to a fully open position, for example. The blower 29b in the exhaust passage 29a is driven. The refrigerant compressed by the compressor 3 passes through the indoor condenser 4, the pressure adjusting means 5, the draft branch 11 (ventilation heat recovery evaporator 13), the second flow switching valve 16, the bypass 15, and the accumulator 9. Cycle through the path. The high-temperature and high-pressure refrigerant compressed by the compressor 3 radiates heat to the air by the indoor condenser 4. The refrigerant having a low temperature due to this heat radiation and having a low pressure by passing through the orifice 5a of the pressure adjusting means 5 absorbs heat from the air by the ventilation heat recovery evaporator 13. Accordingly, the air passing through the air conditioning case 21 passes through the indoor evaporator 8 without being cooled, and all of it is heated by the indoor condenser 4. Thereby, the warm air of desired temperature is produced.

  When the heating capacity of the indoor condenser 4 is small, the heater 26 is operated to produce hot air at a desired temperature.

  In the exhaust heat absorption heating operation, air outside the passenger compartment with low humidity is introduced into the air conditioning case 21 (circulation of the outside air), so that the occurrence of window fogging can be suppressed as much as possible. Further, since the air in the passenger compartment is forcibly exhausted from the exhaust passage 29a to the outside of the passenger compartment, a predetermined air flow is formed in the passenger compartment and no air leakage from the vehicle body from other than the exhaust passage 29a occurs. Is reliably suppressed. For these reasons, window fogging can be suppressed even if the inside air introduction rate is increased to about 50% to reduce the ventilation load. That is, it is possible to save power by reducing the ventilation load while preventing window fogging.

  During the exhaust heat absorption heating operation, it is determined whether or not the freezing of the outdoor heat exchanger 6 has been resolved every predetermined time (step ST5). When it is determined that freezing of the outdoor heat exchanger 6 has been resolved (the outdoor heat exchanger 6 has not been frozen), the outdoor heat absorption heating operation is returned (step ST4).

  In addition, when it determines with the freezing of the outdoor heat exchanger 6 having been eliminated (the outdoor heat exchanger 6 is not frozen), various timings can be considered about the timing which returns to an outdoor air endothermic heating operation.

  As described above, when the outdoor heat exchanger 6 freezes during the outdoor heat absorption heating operation in which the outdoor heat exchanger 6 functions as an evaporator, the heating operation is switched to the exhaust heat absorption heating operation in which the refrigerant absorbs heat in the ventilation heat recovery evaporator 13. In the outside air endothermic heating operation and the exhaust endothermic heating operation, only the heat exchanger that performs the endothermic action is changed. Therefore, it is not necessary to increase the power of the compressor 3 to continue the heating operation. As described above, even when the outdoor heat exchanger 6 is frozen (icing), the heating operation can be maintained without increasing the power of the compressor 3.

  As described above, since the heating operation can be maintained even when the outdoor heat exchanger 6 is frozen, it is not necessary to use a special one as the outdoor heat exchanger 6 (for example, a structure that hardly freezes or a structure in which condensation does not stay as much as possible). A versatile one can be used.

  The outdoor heat exchanger 6 absorbs heat from the outdoor air, but the ventilation heat recovery evaporator 13 absorbs heat from the indoor air, which is hotter than the outdoor air, thus saving power and reducing costs.

  The vapor compression refrigeration cycle 2 is a refrigerant that is supplied to the outdoor heat exchanger 6 with respect to a normal refrigeration cycle including the compressor 3, the indoor condenser 4, the outdoor heat exchanger 6, the temperature type expansion valve 7, and the indoor evaporator 8. Pressure adjusting means 5 capable of adjusting the pressure, a branch branch 11 for bypassing the outdoor heat exchanger 6, an evaporator 13 for recovering ventilation heat disposed in the branch branch 11, and the first refrigerant as an outdoor heat exchanger A first flow path switching valve 12 that can switch between flowing to the 6 side or the ventilation heat recovery evaporator 13 side, a bypass path 15 that bypasses the indoor evaporator 8, and a refrigerant to the indoor evaporator 8 side or bypass path 15 And a second flow path switching valve 16 that can be switched between the flow path and the relatively simple refrigeration cycle configuration, and by relatively simple switching of the refrigerant path, Type of the heating operation (outside air heat absorbing heating operation, the exhaust heat absorbing heating operation) can be performed with one of the cooling operation (cooling reheat operation).

  Since the control means 30 which is a freezing judgment means judges the presence or absence of freezing from the difference between the air blowing temperature of the outdoor heat exchanger 6 and the refrigerant outlet temperature of the outdoor heat exchanger 6, the outdoor heat is surely determined by a relatively simple comparison. Whether or not the exchanger 6 is frozen can be determined.

  In the exhaust endothermic heating operation, the air outside the passenger compartment is introduced into the air conditioning case 21 (the indoor evaporator 8 and the indoor condenser 4), and the air inside the passenger compartment is forcibly exhausted from the exhaust passage 29a. Therefore, since air outside the passenger compartment with low humidity is introduced into the passenger compartment, occurrence of window fogging can be suppressed as much as possible. Further, since the air in the passenger compartment is forcibly exhausted outside the passenger compartment through the exhaust passage 29a, a predetermined air flow is formed in the passenger compartment, and there is no leakage of vehicle body air from other than the exhaust passage 29a. Generation is reliably suppressed. For these reasons, window fogging can be suppressed even if the inside air introduction rate is increased to about 50% to reduce the ventilation load. That is, it is possible to save power by reducing the ventilation load while preventing window fogging.

  In addition to the indoor condenser 4, it has a heater 26 for heating the air supplied to the vehicle interior. And the control means 30 controls the heating amount of the heater 26 based on the detected temperature of the foot blowing temperature detection sensor S4 and the defroster / vent blowing temperature detection sensor S5. Accordingly, even when a temperature difference is provided between the air temperatures of the foot outlet 28a and the vent outlet 28c (bi-level mode), the heating amount of the heater 26 can be adjusted and desired conditioned air can be blown out.

  In this embodiment, the heater 26 is installed. However, in the case of each of the outdoor air endothermic heating operation, the inside air endothermic heating operation, and the exhaust endothermic heating operation, when the heating performance is sufficient only by the indoor condenser 4, the heater 26 is provided. There is no need to install.

  The outdoor heat exchanger 6 includes a plurality of tubes 40 and a pair of tank portions 42 and 43 provided on both ends of the plurality of tubes 40, and a partition wall 48 is provided at one location in each tank portion 42 and 43. 49, respectively, and the partition wall 49 located on the most downstream side in the refrigerant flow path in the outdoor heat exchanger 6 can guide the refrigerant to the liquid reservoir 46, and the refrigerant has a small flow resistance. It is configured to pass through.

  Therefore, when the outdoor heat exchanger 6 functions as a condenser, the refrigerant that has flowed into the one tank portion 42 from the refrigerant inlet 44 flows through the tubes 40 from the tank portion 42 above the partition wall 48. It flows into the other tank part 43. The refrigerant flowing into the other tank portion 43 is guided by the partition wall 49 and enters the liquid reservoir portion 46 through the communication passage 47. The liquid refrigerant overflowed from the liquid reservoir 46 enters the lower side of the other tank 43 through the communication passage 47, flows through the tube 40, flows out of the refrigerant outlet 45, and is sent to the temperature type expansion valve 7. .

  When the outdoor heat exchanger 6 functions as an evaporator, the refrigerant that has flowed into the one tank portion 42 from the refrigerant inlet 44 flows into each tube 40 from the tank portion 42 above the partition wall 48, and the other It flows into the tank part 43. The vaporized refrigerant that has flowed into the other tank portion 43 enters the lower side of the tank portion 43 so as to avoid the partition wall 49 and bypass the communication passage 47. The refrigerant flowing into the lower side of the tank part 43 flows through the tube 40 and flows out from the refrigerant outlet 45 of one tank part 42. When passing through the position of the partition wall 49 in the other tank portion 43, the communication passage 47 is not partitioned by the partition wall 49, and therefore passes with a small passage resistance. Thereby, the pressure loss of the refrigerant flowing in the outdoor heat exchanger 6 can be suppressed to a small value, and the decrease in the heat absorption performance due to the decrease in the evaporation temperature of the refrigerant can be prevented.

  In this embodiment, the pressure adjusting means is composed of the orifice 5a and the bypass passage 5c with the on-off valve 5b connected in parallel to the orifice 5a. However, the pressure adjusting means is in the open state in which the refrigerant passage is opened and the throttle state in which the refrigerant passage is narrowed. As long as it can be selectively switched between. For example, you may comprise with the solenoid valve which can adjust an opening degree.

  In this embodiment, the outdoor heat exchanger 6 is provided with the partition walls 48 and 49 at one place in each of the pair of tank portions 42 and 43, but the partition walls 48 and 49 are provided at two or more places. It may be a thing. In this case, the communication wall 47 is arranged so as not to partition the partition wall 49 located on the most downstream side in the refrigerant flow path in the outdoor heat exchanger 6.

(Structure of modified outdoor heat exchanger)
Next, an outdoor heat exchanger 6A according to a modification will be shown. As shown in FIG. 2 (b), the outdoor heat exchanger 6A according to the modified example has a tank portion 43A on the other side having a larger volume than that of the above embodiment, and the other tank portion 43A has a larger volume. The lower side is configured to also serve as a liquid reservoir. A filter 50 containing a desiccant is built in the other tank portion 43A. The outer peripheral side of the filter 50 in the tank portion 43A is partitioned in the vertical direction by a partition wall 49A. The refrigerant flowing into the upper side of the tank part 43A flows into the lower side of the tank part 43A only through the filter 50. The inner diameter of the partition wall 49A (in other words, the outer diameter of the filter 50) is set to a dimension that allows the vaporized refrigerant to pass through with a small passage resistance. The partition wall 49A has a function of guiding the refrigerant into the filter 50 when the outdoor heat exchanger 6A functions as a condenser. However, when the outdoor heat exchanger 6A functions as an evaporator, the partition wall 49A has a small passage resistance. Pass through.

  Therefore, even in the outdoor heat exchanger 6A according to this modification, like the outdoor heat exchanger 6, when the outdoor heat exchanger 6A functions as a condenser, it flows into the other tank portion 43A. The refrigerant is guided by the partition wall 49A and enters the lower side (corresponding to the liquid reservoir) of the other tank portion 43A through the filter 50. When the outdoor heat exchanger 6 functions as an evaporator, when the outdoor heat exchanger 6 passes through the position of the partition wall 49A in the other tank portion 43A, it passes with a small passage resistance. Thereby, the pressure loss of the refrigerant flowing in the outdoor heat exchanger 6A can be suppressed to be small, and the decrease in the heat absorption performance due to the decrease in the evaporation temperature of the refrigerant can be prevented.

(Modification of switching timing of heating operation)
In the above embodiment, when the outdoor heat exchanger 6 freezes during the outdoor heat absorption heating operation in which the outdoor heat exchanger 6 functions as an evaporator, the exhaust heat absorption heating operation in which the refrigerant absorbs heat in the ventilation heat recovery evaporator 13 is switched. In such a case, the heating operation may be switched.

  In other words, when it is desired to clear the window, or when it is desired to dehumidify in the rain to improve comfort, the outdoor heat absorption heating operation may be switched to the exhaust heat absorption heating operation.

DESCRIPTION OF SYMBOLS 1 Vehicle air conditioner 2 Vapor compression refrigeration cycle 3 Compressor 4 Indoor condenser 5 Pressure adjustment means 6 Outdoor heat exchanger 7 Temperature type expansion valve (pressure reduction means)
8 Indoor evaporator 11 Draft branch 12 First flow path switching valve (first flow path switching means)
13 Ventilation heat recovery evaporator 15 Bypass path 16 Second flow path switching valve (second flow path switching means)
26 Heater (heating means)
28a Foot outlet 28b Defroster outlet 28c Vent outlet 30 Control means 40 Tube 42, 43 Tank part 43A Lower side of tank part (liquid reservoir part)
46 Liquid reservoir 48, 49, 49A Partition wall S1 Outdoor heat exchanger passage air temperature detection means (outdoor heat exchanger passage air temperature detection sensor)
S2 Refrigerant temperature detection means (refrigerant temperature detection sensor)
S4 Foot blowing temperature detection means (foot blowing temperature detection sensor)
S5 Defroster / vent outlet temperature detection means (defroster / vent outlet temperature sensor)

Claims (8)

A compressor (3) for compressing the refrigerant;
An indoor condenser (4) for exchanging heat between the refrigerant compressed by the compressor (3) and the air supplied to the passenger compartment to heat the air;
An outdoor heat exchanger (6) for exchanging heat between the refrigerant and the air outside the vehicle compartment;
A ventilation heat recovery evaporator (13) for exchanging heat between the refrigerant and the air exhausted from the passenger compartment to the outside of the passenger compartment,
The outdoor heat exchanger (6) causes the refrigerant to absorb heat from the air, the indoor condenser (4) causes the refrigerant to dissipate heat to the air, and the ventilation heat recovery evaporator (13) absorbs heat from the air to the refrigerant. A vapor compression refrigeration cycle (2) capable of performing an exhaust heat absorption heating operation in which the indoor condenser (4) causes the refrigerant to radiate heat to the air;
Freezing determination means (30) for determining that the outdoor heat exchanger (6) is frozen;
A vehicle air conditioner (1), comprising: a control means (30) for switching the operation from the outside air endothermic heating operation to the exhaust endothermic heating operation when it is determined that the freezing determination means (30) is frozen. A vehicle air conditioner (1) according to claim 1,
A vehicle air conditioner (1) having a blower (29b) that blows air inside the passenger compartment to the outside of the passenger compartment through the evaporator (13) for recovering ventilation heat. A vehicle air conditioner (1) according to claim 1 or claim 2,
The vapor compression refrigeration cycle (2) includes pressure adjusting means (5) capable of adjusting the pressure of refrigerant supplied to the outdoor heat exchanger (6) and the ventilation heat recovery evaporator (13), and the outdoor heat exchange. A bypass branch passage (11) in which the evaporator (6) is bypassed and the ventilation heat recovery evaporator (13) is disposed, and the refrigerant is flowed to the outdoor heat exchanger (6) side or the ventilation heat recovery evaporator (13) first flow path switching means (12) that can switch whether to flow to the side,
In the outdoor heat absorption heating operation, the refrigerant compressed by the compressor (3) passes through the indoor condenser (4), the pressure adjusting means (5), and the outdoor heat exchanger (6), and the compressor (3). And the refrigerant is depressurized by the pressure adjusting means (5), and the refrigerant is absorbed from the air by the outdoor heat exchanger (6),
In the exhaust heat absorption heating operation, the refrigerant compressed by the compressor (3) passes through the indoor condenser (4), the pressure adjusting means (5), the ventilation heat recovery evaporator (13), and the compressor (3 The vehicle air conditioner (1) is characterized in that the refrigerant is depressurized by the pressure adjusting means (5), and the ventilation heat recovery evaporator (13) causes the refrigerant to absorb heat from the air. The vehicle air conditioner (1) according to claim 3,
The vapor compression refrigeration cycle (2) includes an indoor evaporator (8) that cools air by exchanging heat between the refrigerant and air supplied to the vehicle interior, and a refrigerant that is supplied to the indoor evaporator (8). Switching between pressure reducing means (7) for reducing the pressure, bypass passage (15) for bypassing the indoor evaporator (8), and whether the refrigerant flows to the indoor evaporator (8) side or the bypass passage (15) Second flow path switching means (16) capable of,
The indoor evaporator (8) can perform a cooling reheat operation in which the refrigerant absorbs heat from the air, and the indoor condenser (4) and the outdoor heat exchanger (6) dissipate heat to the refrigerant.
In the cooling reheat operation, the refrigerant compressed by the compressor (3) is converted into the indoor condenser (4), the pressure adjusting means (5), the outdoor heat exchanger (6), the pressure reducing means (7), the indoor A refrigerant path is returned to the compressor (3) through the evaporator (8), and the refrigerant is passed through the pressure adjusting means (5) without being depressurized, and is radiated to the refrigerant by the outdoor heat exchanger (6). The vehicle air conditioner (1) characterized by the above-mentioned. The vehicle air conditioner according to any one of claims 1 to 4,
The outdoor heat exchanger passing air temperature detection means (S1) for detecting the temperature of the air that has passed through the outdoor heat exchanger (6), and the refrigerant temperature detection for detecting the refrigerant temperature on the outlet side of the outdoor heat exchanger (6). Means (S2),
The freezing determination means (30) is configured to detect the passage air temperature of the outdoor heat exchanger (6) detected by the outdoor heat exchanger passage air temperature detection means (S1) and the refrigerant temperature detection means (S2). The vehicle air conditioner (1), wherein the presence or absence of freezing is determined from the difference from the refrigerant outlet temperature of the outdoor heat exchanger (6). A vehicle air conditioner (1) according to any one of claims 1 to 5,
A vehicle air conditioner (1), wherein air outside the passenger compartment is introduced into the indoor condenser (4) during exhaust heat absorption heating operation. The vehicle air conditioner (1) according to any one of claims 1 to 6,
In addition to the indoor condenser (4), heating means (26) for heating the air supplied to the vehicle interior;
Foot blowing temperature detecting means (S4) for detecting the temperature of air blown from the foot blowing outlet (28a);
Defroster vent outlet temperature detecting means (S5) for detecting the air temperature blown out from the defroster outlet (28b) and the vent outlet (28c);
The control means (30) controls the heating amount of the heating means (26) based on the detected temperatures of the foot blowing temperature detecting means (S4) and the defroster / vent blowing temperature detecting means (S5). A vehicle air conditioner (1). A vehicle air conditioner (1) according to any one of claims 1 to 7,
The outdoor heat exchangers (6), (6A) include a plurality of tubes (40) and a pair of tank portions (42), (43), (43A) provided on both ends of the tubes (40). Partition walls (48), (49), (49A) are provided in the tank portions (42), (43), (43A),
The partition walls (49) and (49A) located on the most downstream side in the refrigerant flow paths in the outdoor heat exchangers (6) and (6A) are arranged so that the refrigerant enters the liquid reservoirs (46) and (43A). A vehicle air conditioner (1) characterized by being capable of guiding and allowing a refrigerant to pass therethrough with a small flow resistance.

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