JP2006118783A - Refrigerating cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce variation in amount of refrigerant recovery by refrigerant recovery control to reduce required capacity of an accumulator tank, in a refrigerating cycle device operable in a hot gas cycle. <P>SOLUTION: The refrigerating cycle device blocks the inlet side of a condenser 14 with a solenoid valve 13, opens the inlet side of a hot gas bypass passage 20, and performs the operation of heating mode by hot gas bypass. When the heating mode is started, in a refrigerant recovery operation of recovering refrigerants on the condenser 14 side to an evaporator 18 side by operating a compressor 10 while the inlet sides of both of the condenser 14 and a hot gas bypass passage 19 are blocked for a predetermined time by the solenoid valve 13, a cooling fan of the condenser is operated, and the cooling fan is further operated for a predetermined time also in the start of the hot gas cycle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a refrigeration cycle apparatus, and in particular, depressurizes high-temperature and high-pressure gas refrigerant discharged from a refrigerant compressor, leads it to a refrigerant evaporator, and uses the refrigerant evaporator as a gas refrigerant radiator. The present invention relates to a refrigeration cycle apparatus having a hot gas bypass function for heating air, and more particularly to a vehicle air conditioner.

  Conventionally, in a vehicle air conditioner, warm water (engine cooling water) is circulated to a heating heat exchanger during heating in winter, and the heated air is heated by the heating heat exchanger using the warm water as a heat source. . In this case, when the hot water temperature is low, the temperature of the air blown into the passenger compartment may decrease and the required heating capacity may not be obtained.

  Therefore, conventionally, an air conditioner that exhibits a heating function by hot gas bypass has been proposed. In this conventional apparatus, when the hot water temperature is lower than a predetermined temperature, such as when the engine is started, the compressor discharge gas refrigerant (hot gas) in the refrigeration cycle is introduced into the evaporator bypassing the condenser. Heat is released from the gas refrigerant to the conditioned air so that the heating function can be exhibited. However, in the hot gas cycle using the high-temperature and high-pressure gas refrigerant in the refrigeration cycle, the excess or deficiency of the refrigerant filling amount greatly affects the heating capacity. For example, if the refrigerant filling amount is insufficient, the heating capacity is lowered, and if the refrigerant filling amount is excessive, the compressor may cause liquid compression. Therefore, it is necessary to enlarge the accumulator tank so as not to perform liquid compression.

  Thus, when operating a hot gas cycle, it is first necessary to recover the refrigerant remaining in the condenser and its associated piping, that is, the sleeping refrigerant. FIG. 7 shows a conventional example of control in an air conditioner capable of recovering a sleeping refrigerant. In this case, when the air conditioner is started in step 101 (S101), it is confirmed in step 104 (S104) whether the heater mode (heating operation) is performed. In addition, the compressor (compressor) is turned on and the operation is performed in the cooler mode, and the refrigerant recovery control is performed to recover the refrigerant in the accumulator tank on the evaporator (evaporator) side (step 105 (S105) and step 106 (S106)) After the necessary amount of refrigerant is recovered from the condenser (condenser) side, the hot gas cycle operation is started in step 107 (S107).

  Conventionally, refrigerant recovery control is performed in order to secure the amount of refrigerant and oil necessary for the system in the hot gas cycle. There have been proposed conventional air conditioners that can collect such a sleeping refrigerant (see, for example, Patent Documents 1 to 4).

Since the hot gas cycle is a system that is used when the outside air temperature is low, the cooling fan has not been operated even during the cooler operation during the refrigerant recovery control from the viewpoint of refrigerant recoverability at low temperatures and power saving.
When the refrigerant recovery control is performed during idling, the condenser pressure during cooler operation tends to rise, and when switching to hot gas operation, the pressure difference between the condenser and the evaporator is large, and it is provided between the condenser and the evaporator. The time until the check valve closes (operating condition: the pre-evaporator pressure becomes larger than the condenser pressure) becomes longer, and the refrigerant tends to flow out of the condenser to the evaporator (reversely, the refrigerant is easy to recover).
However, since the cooling air is applied to the condenser during driving, the condenser pressure during cooler operation is unlikely to rise, and even when switching to hot gas operation, the pressure difference between the condenser and the evaporator is small, and the check valve operates. Since the time is shorter than when idling, the amount of refrigerant flowing out of the condenser is smaller than when idling.
As described above, in the conventional control, there is a difference in the refrigerant recovery amount between idling and traveling, so that it was necessary to enlarge the accumulator tank in order to fill the difference.

JP-A-5-272817 Japanese Patent Laid-Open No. 10-334389 JP 2003-322420 A JP 2000-219033

As described above, in a refrigeration cycle apparatus such as an air conditioner that performs a hot gas cycle, refrigerant recovery control is necessary to exhibit sufficient heating performance. However, in the air conditioner equipped with the refrigerant recovery control of the prior art, the refrigerant recovery amount varies depending on the operation state of the vehicle, and it is necessary to increase the capacity of the accumulator tank in order to absorb this variation.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a refrigeration cycle apparatus or an air conditioner that can reduce the variation in the refrigerant recovery amount by the refrigerant recovery control and reduce the required capacity of the accumulator tank. To do.
Another object of the present invention is to reduce the space occupied by the refrigeration cycle apparatus or the air conditioner by reducing the capacity of the accumulator tank, and to reduce the cost of the apparatus.

  According to the first aspect of the present invention, in order to achieve the above-described object, a refrigeration cycle apparatus operable in a hot gas cycle is positioned downstream of the compressor for compressing refrigerant and the compressor. A condenser that cools the refrigerant by exchanging heat between the refrigerant compressed by the compressor and external air, the condenser including a cooling fan, and the external air is A condenser, a first decompression device that decompresses the refrigerant condensed by the condenser, and a refrigerant decompressed by the first decompression device that are supplied by the cooling fan, evaporate the heat, and exchange heat with external air. An evaporator and a control device for controlling the refrigeration cycle apparatus. When the hot gas cycle operation is performed, the refrigeration cycle apparatus is controlled by the control device so that the refrigerant recovery operation is performed in advance before the hot gas cycle operation. In the refrigerant recovery operation, the refrigeration cycle device circulates the refrigerant compressed by the compressor through the condenser for a predetermined time, and operates the cooling fan of the condenser at this time. .

  With this configuration, in the air conditioner that performs the hot gas cycle, when the refrigerant recovery control for exhibiting sufficient heating performance is performed, the change in the driving state of the vehicle during idling, traveling, etc. The required capacity of the accumulator tank can be reduced by reducing the variation in the refrigerant recovery amount due to. As a result, the occupying space of the refrigeration cycle apparatus is reduced, and the cost of the apparatus is further reduced.

According to a second aspect of the present invention, in the first aspect, the refrigeration cycle apparatus further includes a bypass pipe that bypasses the condenser and allows the refrigerant to flow directly from the compressor to the evaporator. To do. In the refrigerant recovery operation, the refrigerant pipe from the compressor to the condenser is in an open state, and the refrigerant pipe from the compressor to the bypass line is set in a closed state.
According to the present embodiment, a more specific configuration is disclosed.

According to a third aspect of the present invention, in any one of the first and second aspects, the compressor is stopped for a predetermined time after the refrigerant recovery operation and before the start of the hot gas cycle operation. It is characterized by being.
According to this embodiment, there is a possibility that variations in the refrigerant recovery amount due to changes in the operating state can be further reduced.

According to a fourth aspect of the present invention, in the third aspect, the compressor is stopped after a predetermined time after the refrigerant recovery operation and before the start of the hot gas cycle operation. A cooling fan is operated.
According to this embodiment, there is a possibility that the variation in the refrigerant recovery amount due to the change in the operating state can be further reduced.

In the form of Claim 5 of this invention, although the said hot gas cycle driving | operation is implemented after the said refrigerant | coolant collection | recovery driving | operation in any one of the form of the said Claim 1 to 4, at the time of the said hot gas cycle driving | operation start, The cooling fan is operated for a predetermined time.
According to this embodiment, there is a possibility that variations in the refrigerant recovery amount due to changes in the operating state can be further reduced.

In the form of Claim 6 of this invention, although the said hot gas cycle driving | operation is implemented after the said refrigerant | coolant collection | recovery driving | operation in any one of the form of the said Claim 1 to 4, at the time of the said hot gas cycle driving | operation start, The cooling fan is operated until the internal pressure of the condenser becomes lower than the pre-evaporator pressure.
According to this embodiment, there is a possibility that variations in the refrigerant recovery amount due to changes in the operating state of the vehicle, such as when idling or traveling, can be reduced, and the refrigerant recovery amount can be adjusted more appropriately.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the refrigeration cycle apparatus is a vehicle air conditioner.
According to this embodiment, a more specific application of the present invention is disclosed.

  In the form of claim 8 of the present invention, in order to achieve the above-mentioned object, a control method of hot gas cycle operation of a refrigeration cycle apparatus operable with a hot gas cycle is disclosed, and the refrigeration cycle apparatus comprises: A compressor for compressing the refrigerant, and a condenser that is located downstream of the compressor and cools the refrigerant by exchanging heat between the refrigerant compressed by the compressor and external air. The condenser includes a cooling fan, and the external air is supplied by the cooling fan. The condenser is located downstream of the condenser, and the refrigerant condensed in the condenser is supplied to the condenser. A first depressurizing device for depressurizing; an evaporator for evaporating the refrigerant depressurized by the first depressurizing device and exchanging heat with external air; and a control device for controlling the refrigeration cycle device. . In the control method, when the hot gas cycle operation is performed, a refrigerant recovery step in which the refrigerant recovery operation is performed in advance before the hot gas cycle operation, and the hot gas cycle operation is performed after the refrigerant recovery step. The process to comprise. In the refrigeration cycle apparatus, the refrigerant recovery step includes a circulation procedure for circulating the refrigerant compressed by the compressor through the condenser for a predetermined time, and the cooling fan of the condenser is operated in parallel with the circulation procedure. And a cooling fan operation procedure.

  With this configuration, in the air conditioner that performs the hot gas cycle, when the refrigerant recovery control for exhibiting sufficient heating performance is performed, the change in the driving state of the vehicle during idling, traveling, etc. The required capacity of the accumulator tank can be reduced by reducing the variation in the refrigerant recovery amount due to. As a result, the space occupied by the refrigeration cycle apparatus is reduced, and the cost of the apparatus is further reduced.

According to a ninth aspect of the present invention, in the above-mentioned eighth aspect, the refrigeration cycle apparatus further includes a bypass pipe that bypasses the condenser and allows the refrigerant to flow directly from the compressor to the evaporator. To do. In the refrigerant recovery step, the refrigerant piping from the compressor to the condenser is set to an open state, and the refrigerant piping from the compressor to the bypass line is set to a closed state. And
According to this embodiment, the configuration of the present invention is further embodied.

According to a tenth aspect of the present invention, in any one of the eighth and ninth aspects, the compressor is determined in advance between the refrigerant recovery step and the step of performing the hot gas cycle operation. The method further includes a step of stopping for a predetermined time.
According to this embodiment, there is a possibility that variations in the refrigerant recovery amount due to changes in the operating state can be further reduced.

According to an eleventh aspect of the present invention, in the form of the tenth aspect, the cooling fan is operated in the step of stopping the compressor for a predetermined time.
According to this embodiment, there is a possibility that the variation in the refrigerant recovery amount due to the change in the operating state can be further reduced.

According to a twelfth aspect of the present invention, in the method according to any one of the eighth to eleventh aspects, the step of performing the hot gas cycle operation includes a procedure of operating the cooling fan for a predetermined time at the start thereof. It is characterized by comprising.
According to this embodiment, there is a possibility that variations in the refrigerant recovery amount due to changes in the operating state can be further reduced.

According to a thirteenth aspect of the present invention, in the method according to any one of the eighth to eleventh aspects, the step of performing the hot gas cycle operation is configured such that the cooling fan is connected to the condenser internal pressure at the start thereof. Comprising a procedure of operating until the pressure becomes lower than the pre-evaporator pressure.
According to this embodiment, there is a possibility that variations in the refrigerant recovery amount due to changes in the operating state of the vehicle, such as when idling or traveling, can be reduced, and the refrigerant recovery amount can be adjusted more appropriately.

According to a fourteenth aspect of the present invention, in any one of the eighth to thirteenth aspects, the refrigeration cycle apparatus is a vehicle air conditioner.
According to this embodiment, a more specific application of the present invention is disclosed.

  Hereinafter, a refrigeration cycle apparatus according to an embodiment of the present invention, that is, an air conditioner will be described in detail with reference to the drawings. In the following embodiment, the refrigeration cycle apparatus will be described as a vehicle air conditioner. 1 and 2 illustrate an embodiment of a vehicle air conditioner according to the present invention. FIG. 1 is a system diagram showing a schematic configuration of an air conditioner 1 according to an embodiment of the present invention. FIG. 2 is a block diagram of a control system of the air conditioner ECU 26 in FIG.

  Referring first to FIG. 1, the air conditioner 1 of the present embodiment cools and condenses the refrigerant by the compressor (compressor) 10 that compresses the refrigerant to high temperature and high pressure and the outside air blown by the blower fan 14a. A condenser (condenser) 14, a pressure reducing valve (first pressure reducing device) 16 that adiabatically expands the condensed refrigerant to lower its temperature, and air-conditioned air blown out to the passenger compartment by the blower fan 23 during cooling are cooled by the refrigerant. An evaporator (evaporator) 18 and an air conditioner ECU 26 that controls the air conditioner 1 are provided. The structure of such an air conditioner is general. In addition, the air conditioner 1 includes accumulator tanks 15 and 19 that store refrigerant and separate gas and liquid, respectively, on the downstream side of the condenser 14 and between the compressor 10 and the evaporator 18. A first pressure reducing device (expansion valve) 16 and a check valve 17 are disposed downstream of the condenser 14.

  The air conditioner 1 uses the cooling water of the engine 12 as a heat source during heating and supplies it to the heater unit 24 to warm the conditioned air. However, the air conditioner 1 of the present embodiment also has a hot gas cycle function. Sometimes, the refrigerant compressed by the compressor 10 is decompressed through the second decompression device 21 a and then supplied to the evaporator 18, so that the conditioned air can also be warmed by the evaporator 18. At this time, the high-temperature and high-pressure refrigerant compressed by the compressor 10 bypasses the condenser 14 by operating (ON) the electromagnetic switching valve 13, passes through the second decompression device 21a, and is hot. The gas is supplied to the evaporator 18 through the gas bypass passage 20 (heating hot gas heater cycle H). When the switching valve 13 is off (OFF), the hot gas bypass passage 20 is closed and the passage of the cooling refrigeration cycle C is opened.

The hot gas cycle is also controlled by the air conditioner ECU 26, but the main input signals and output signals regarding the control of the air conditioner 1 performed by the air conditioner ECU 26 are shown in FIG. The air conditioner ECU 26 receives switch signals such as operation modes (29a to 29f) by various switches such as a hot gas switch for sending a command to execute a hot gas cycle, and further outputs an outside air temperature 27b from various sensors. Sensor signals (27a to 27f) as control parameters are input.
The configuration of the air-conditioning apparatus 1 capable of performing such a hot gas cycle and the configuration of the control system thereof are general, and details thereof are omitted because they are not necessary for further understanding of the present invention.

A control method related to the hot gas cycle of the air conditioner 1 of the present embodiment will be described with reference to FIG. In order to make the explanation easy to understand, the control flow in FIG. 3 shows only the part related to the present invention, and the control not directly related to the present invention is omitted. Various control procedures for controlling the air conditioner may be incorporated in the control flow.
When the air conditioner 1 is started in step 1 (S1), the process proceeds in the order of step 2 (S2) and step 3 (S3), the switch signal is read in step 2, and the sensor signal is further read in step 3 (S3). Read. Thereafter, the process proceeds from step 3 to step 4 (S4), and it is determined whether or not the heater (heating) mode (or the cooler (cooling) mode) is set. Whether or not the heater mode is selected is input by a switch signal.

In the heater mode (YES), the process proceeds to step 5 (S5), and refrigerant recovery control is started. In step 5, the cooler operation is performed for a predetermined time (T1) as in the conventional example. At this time, the compressor 10 is turned on, the switching valve 13 is turned off (OFF), and the line of the cooling refrigeration cycle C is opened. It is done. If YES in step 4, the control flow proceeds to step 5 and at the same time proceeds to step 20 (S20). In step 20, the blower fan 14a of the condenser 14 is turned on, and the blower fan 14a is operated for T3 time. Here, the control procedure of Step 5 and the control procedure of Step 20 are performed in parallel. The blower fan 14 a acts as a cooling fan, condenses and liquefies the refrigerant in the condenser 14, and the liquid refrigerant is mainly stored in the condenser 14 or the accumulator tank 15. When the time T1 has elapsed, the process proceeds from step 5 to step 6 (S6). In step 6, the cooler operation is stopped for a time T2. That is, the compressor 10 is turned off and the switching valve 13 is turned off. Here, T ₂ = 0 may be used.

  When the time T2 has elapsed, the process proceeds from step 6 to step 7 (S7), and the hot gas cycle (operation) is started. Here, since T3> T1 + T2 is set, the step 20 in parallel progress is continued, and the blower fan 14a is continuously operated. Accordingly, part of the refrigerant in the condenser 14 is condensed and liquefied even during this time, and the liquid refrigerant is stored in the condenser 14 or the accumulator tank 15. When the time T3 elapses, step 20 ends, and the blower fan 14a, which is a cooling fan, is turned off and stopped. Since the current state is maintained in step 8 (S8), the hot gas cycle in step 7 is continued. In the case of NO in step 4 of the control flow shown in FIG. 3 above, since it is the cooler mode, the process proceeds to step 30 (S30) and the cooler mode is performed. Since the cooler mode is not directly related to the present invention, the description is omitted.

  As described above, in the present embodiment, by operating the blower fan 14a during the refrigerant recovery control, the liquefied refrigerant is accumulated in the condenser 14 or the accumulator tank 15 even during idling, and the condenser 14 and the surrounding piping. The refrigerant inside can also be recovered. In this way, by operating the cooling fan (blower fan 14a) for a certain period of time (T3, T3> T1 + T2) from the start of the refrigerant recovery control, variation in the refrigerant recovery amount due to changes during idling, running, etc. is reduced, and The tank can be reduced in size.

  FIG. 4 shows a control flow of the second embodiment of the present invention. The control flow of the second embodiment is basically similar to the control flow of the first embodiment. The difference is that, in the second embodiment, the operation of the cooling fan (blower fan 14a) for refrigerant recovery control is stopped by comparing the condenser internal pressure and the evaporator pre-pressure. That is, in the present embodiment, the operation of the cooling fan 14a is stopped when the condenser internal pressure decreases and becomes lower than the evaporator pre-pressure.

In the control flow of the second embodiment in FIG. 4, steps 1 (S1) to 4 (S4) are the same as those in the first embodiment. When the heater mode is set in step 4 (YES), the process proceeds to step 15 (S15), and refrigerant recovery control is started. In step 15, the cooler operation is performed for T1 time. At this time, the compressor 10 is turned on, the switching valve 13 is turned off, and the cooling fan 14a is also turned on in one place. After the time T1 has elapsed, the process proceeds to step 16 (S16). In step 16, the compressor 10 and the switching valve 13 are turned off, but the cooling fan 14a is continuously operated (turned on) and is operated for T2 time. Thereafter, the process proceeds to Step 17 (S17). In step 17, a hot gas cycle is started (the compressor 10 is turned on and the switching valve 13 is turned on (opened)), but the cooling fan 14a continues to operate. Here, T ₂ = 0 may be used.

  The operation from step 15 (S15) to step 17 (S17) in the second embodiment is substantially the same as the operation state from step 5 (S5) to step 7 (S7) in the first embodiment. is there. In the second embodiment, the process proceeds to step 18 (S18) in step 17, and the condenser internal pressure and the evaporator pre-pressure are compared. At this time, since the refrigerant compressed by the compressor 10 in step 15 is supplied to the refrigerant refrigeration cycle C of FIG. 1 including the condenser 14 when the switching valve 13 is off, the internal pressure of the condenser is reduced to the evaporator. It becomes higher than the pre-pressure. When the hot gas cycle operation is started in step 17, the switching valve 13 is turned on, and the refrigerant is supplied to the heating hot gas heater cycle H in FIG. Rises and the condenser internal pressure drops. In step 18 (S18), when the condenser internal pressure is equal to or higher than the evaporator pre-pressure (NO), the process returns to step 17 and the hot gas cycle for operating the cooling fan 14a is continued. When the internal pressure of the condenser decreases and becomes lower than the pre-evaporator pressure, the process proceeds to step 18 in the YES direction, that is, the process proceeds to step 19 (S19).

  In step 19, it is operated in a normal hot gas cycle, and the cooling fan 14a is stopped. In step 8 (S8), the current state is maintained. Thus, the state in which the condenser internal pressure is lower than the evaporator pre-pressure is set as a state in which the refrigerant amount is stable in the heating hot gas heater cycle H in FIG. 1 for the hot gas cycle. In step 4 (S4), when the heater mode is not selected (NO), the process proceeds to step 30 (S30), and the cooler mode is operated as in the first embodiment. Steps (procedures) of the control flow of the second embodiment of FIG. 4 that are the same as or similar to the steps of the control flow of the first embodiment of FIG. 3 are designated by the same step numbers.

  The test results during idle operation when the improved control according to the first embodiment of the present invention is applied to the refrigeration cycle apparatus that performs the hot gas cycle will be described with reference to the test measurement result graph of FIG. FIG. 9 shows a graph of test results during idle operation (vehicle speed = 0) in the conventional control example, and the effects of the present invention can be clearly understood by comparing these test results. FIG. 5 is a schematic three-dimensional view for explaining the refrigerant circuit when the improved control of the present invention is performed, and shows the measurement position in the refrigerant circuit of the pressure in the graph of FIG. FIG. 8 is a view similar to FIG. 5 for explaining the conventional example of FIG. The circuit system of FIGS. 5 and 8 is basically the same as the circuit system of FIG.

  In the graph of FIG. 6, the test was performed with T2 set to zero. The condenser refrigerant weight W in FIG. 6 indicates the amount of refrigerant in the condenser 14. Pd and Ps indicate the discharge side and suction side pressures of the compressor 10, respectively, and Ph and Pe indicate the pressure in the condenser 14 and the pressure before the evaporator 18, respectively. In FIG. 6, the refrigerant recovery operation (control) time T1 is 30 seconds, T2 is 0 seconds, and the hot gas cycle operation is started after 30 seconds. Therefore, the compressor 10 was continuously operated, and the cooling (fan) fan 14a was operated for about 90 seconds. When the refrigerant recovery operation (control) starts, the refrigerant is supplied to the condenser 14, so that the internal pressure Ph of the condenser 14 increases and the refrigerant weight W in the condenser 14 also increases. Here, since the cooling fan 14a is operated from the start of the refrigerant recovery operation (0 seconds) and the cooling air is applied to the condenser 14, a part of the refrigerant in the condenser 14 is liquefied and accumulated on the condenser 14 side. A part of the refrigerant flows out of the condenser 14. Therefore, the refrigerant weight W in the condenser 14 decreases. Since the refrigerant recovery operation is completed and the hot gas cycle operation is started when T1 is about 30 seconds, the refrigerant is supplied from the compressor 10 to the evaporator 18 without being supplied to the condenser 14. On the other hand, at the start of the hot gas cycle operation, the condenser internal pressure Ph is still higher than the pre-evaporator pressure Pe, so that the refrigerant in the condenser 14 flows to the evaporator 18. However, since the cooling fan 14a is continuously operated at this time, the condenser 14 continues to be cooled, so the pressure drop of the condenser 14 is quick, and the condenser internal pressure Ph is lower than the pre-evaporator pressure Pe. At that time, the refrigerant does not flow from the condenser 14 to the evaporator. The refrigerant weight W remaining in the condenser 14 was about 200 g.

  On the other hand, in the conventional control example shown in FIG. 9, the refrigerant flows into the condenser 14 at the start of the refrigerant recovery operation, and the pressure Ph and the refrigerant weight W in the condenser 14 rapidly increase. However, since the cooling air is not applied to the condenser 14, the condenser 14 internal pressure Ph is likely to rise, and the refrigerant is the condenser 14 internal pressure Ph and the evaporator 18 pre-pressure. It continues to flow from the condenser 14 side to the evaporator 18 according to the pressure difference of Pe. Further, the condenser 14 internal pressure Ph does not receive cooling air, so that the pressure drop is slow, and the refrigerant continues to flow from the condenser 14 to the evaporator until the condenser internal pressure Ph becomes lower than the pre-evaporator pressure Pe. Therefore, it can be seen that the refrigerant weight W in the condenser 14 is significantly reduced as compared with the first embodiment, and the refrigerant remaining amount on the condenser 14 side is small. The refrigerant weight W in the condenser 14 was about 100 g. In the conventional control example test, the stop time T2 of the compressor 10 after the refrigerant recovery operation was about 15 seconds.

  During traveling of the vehicle in the conventional control example, the cooling air hits the condenser 14 during traveling, so it is considered that the test results are close to the test results of the first embodiment of the present invention. That is, the above test can be regarded as a comparison between idling (corresponding to the above-described conventional control) and running (similar to the test of the first embodiment of the present invention) in the conventional control example. Thus, it can be seen that in the conventional control example, the refrigerant recovery amount varies greatly between idling and traveling. As can be seen from the test results of the first embodiment of the present invention and the test results of the conventional control example, in the case of the present invention, the amount of refrigerant remaining in the condenser 14 is large. There is no difference (variation) in the amount of recovered refrigerant, and therefore there is no need to provide a large capacity tank on the evaporator 18 side.

Next, effects and operations of the above embodiment will be described.
The following effects can be expected from the air conditioner according to the first embodiment of the present invention.
・ When refrigerant recovery control is performed to demonstrate sufficient heating performance in air conditioning systems that implement hot gas cycles, variations in the amount of refrigerant recovered due to changes in vehicle operating conditions such as idling and traveling By reducing it, the required capacity of the accumulator tank can be reduced.
-Due to the above effects, the space occupied by the air conditioner can be reduced, and the cost of the apparatus can be further reduced.

In addition to the effect of said 1st Embodiment, the following effects can be anticipated by the air conditioner of the 2nd Embodiment of this invention.
-There is a possibility that the variation in the refrigerant recovery amount due to a change in the driving state of the vehicle during traveling or the like can be reduced, and the refrigerant recovery amount can be adjusted more appropriately.

In the above description, the apparatus of the present invention has been described as an air conditioner. However, the apparatus may be a refrigeration cycle apparatus capable of performing a refrigeration cycle other than the air conditioner.
In the embodiment described above or in the attached drawings, particularly shown in FIGS. 1 and 2, the specific configuration of the air conditioner is shown. It shows a general configuration that can be implemented, and the present invention is not limited thereto, additional components may be further incorporated into this configuration, or some additional components may be incorporated from this configuration. Various components may be deleted.

  In addition, the control flow described in the above embodiment is described as an example for explaining a part related to the present invention, and the control procedure of various refrigeration cycle apparatuses such as an air conditioner is included in these control flows. May be added.

  The above-described embodiment is an example of the present invention, and the present invention is not limited by the embodiment, but is defined only by matters described in the claims, and other embodiments than the above are also possible. It can be implemented.

FIG. 1 is a system diagram showing a schematic configuration of an embodiment of a vehicle air conditioner according to the present invention. FIG. 2 is a block diagram of a control system according to the present invention of the air conditioner ECU in FIG. FIG. 3 shows a control flow of the first embodiment of the present invention. FIG. 4 shows a control flow of the second embodiment of the present invention. FIG. 5 is a schematic three-dimensional view of a test refrigerant circuit in which the improved control of the present invention is performed, and is for explaining the test result graph of FIG. FIG. 6 shows a graph of test results when the improved control of the first embodiment of the present invention is applied. FIG. 7 shows a conventional control flow. FIG. 8 is a schematic three-dimensional view of a test refrigerant circuit in which the control of the conventional example is performed, and is for explaining a graph of the test result of the conventional example of FIG. FIG. 9 shows a graph of a test result when the control of the conventional example is applied, and is a case where the vehicle speed is zero.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air conditioner 10 Compressor 12 Engine 14a Blower fan (cooling fan)
DESCRIPTION OF SYMBOLS 13 Switching valve 14 Condenser 15 Accumulator tank 16 1st pressure reduction device 17 Check valve 18 Evaporator 19 Accumulator tank 20 Hot gas bypass passage 21a 2nd pressure reduction device 23 Blower fan 24 Heater unit 26 Air-conditioner ECU

Claims (14)

In a refrigeration cycle apparatus operable with a hot gas cycle, the refrigeration cycle apparatus is:
A compressor for compressing the refrigerant;
A condenser that is located downstream of the compressor and cools the refrigerant by exchanging heat between the refrigerant compressed by the compressor and external air, the condenser comprising a cooling fan A condenser, wherein the external air is supplied by the cooling fan;
A first pressure reducing device that depressurizes the refrigerant condensed in the condenser;
An evaporator that evaporates the refrigerant decompressed by the first decompressor and exchanges heat with external air; and
A control device for controlling the refrigeration cycle device;
It has
When performing the hot gas cycle operation, the refrigeration cycle apparatus is controlled by the control device so that the refrigerant recovery operation is performed in advance before the hot gas cycle operation,
In the refrigerant recovery operation, the refrigeration cycle device circulates the refrigerant compressed by the compressor through the condenser for a predetermined time, and operates the cooling fan of the condenser at this time. Refrigeration cycle equipment. The refrigeration cycle apparatus further includes a bypass pipe that bypasses the condenser and allows the refrigerant to flow directly from the compressor to the evaporator.
2. The refrigerant pipe from the compressor to the condenser is set in an open state and the refrigerant pipe from the compressor to the bypass pipe is set in a closed state in the refrigerant recovery operation. The refrigeration cycle apparatus described in 1.   The refrigeration cycle apparatus according to claim 1 or 2, wherein the compressor is stopped for a predetermined time after the refrigerant recovery operation and before the hot gas cycle operation is started.   4. The refrigeration cycle according to claim 3, wherein the cooling fan is operated while the compressor is stopped for a predetermined time after the refrigerant recovery operation and before the hot gas cycle operation is started. apparatus.   5. The hot gas cycle operation is performed after the refrigerant recovery operation, and at the start of the hot gas cycle operation, the cooling fan is operated for a predetermined time. The refrigeration cycle apparatus described.   The hot gas cycle operation is performed after the refrigerant recovery operation. At the start of the hot gas cycle operation, the cooling fan is operated until the pressure in the condenser becomes lower than the pre-evaporator pressure. The refrigeration cycle apparatus according to any one of claims 1 to 4, wherein the refrigeration cycle apparatus is characterized in that:   The refrigeration cycle apparatus according to any one of claims 1 to 6, wherein the refrigeration cycle apparatus is a vehicle air conditioner. A compressor for compressing the refrigerant;
A condenser that is located downstream of the compressor and cools the refrigerant by exchanging heat between the refrigerant compressed by the compressor and external air, the condenser comprising a cooling fan A condenser, wherein the external air is supplied by the cooling fan;
A first pressure reducing device that depressurizes the refrigerant condensed in the condenser;
An evaporator that evaporates the refrigerant decompressed by the first decompressor and exchanges heat with external air; and
A control device for controlling the refrigeration cycle device;
In the control method of the hot gas cycle operation of the refrigeration cycle apparatus, which can be operated in the hot gas cycle,
When performing the hot gas cycle operation, a refrigerant recovery step of performing a refrigerant recovery operation in advance before the hot gas cycle operation;
A step of performing the hot gas cycle operation after the refrigerant recovery step;
It has
The refrigerant recovery step includes
In the refrigeration cycle apparatus, a circulation procedure for circulating the refrigerant compressed by the compressor through the condenser for a predetermined time;
In parallel with the circulation procedure, a cooling fan operation procedure for operating the cooling fan of the condenser;
The control method of the refrigerating-cycle apparatus characterized by comprising. The refrigeration cycle apparatus further includes a bypass pipe that bypasses the condenser and allows the refrigerant to flow directly from the compressor to the evaporator.
In the refrigerant recovery step, the refrigerant piping from the compressor to the condenser is set to an open state, and the refrigerant piping from the compressor to the bypass line is set to a closed state. The control method according to claim 8.   10. The method according to claim 8, further comprising a step of stopping the compressor for a predetermined time between the refrigerant recovery step and the step of performing the hot gas cycle operation. The control method described.   The control method according to claim 10, wherein the cooling fan is operated in the step of stopping the compressor for a predetermined time.   The control method according to any one of claims 8 to 11, wherein the step of performing the hot gas cycle operation includes a procedure of operating the cooling fan for a predetermined time at the start thereof.   The step of performing the hot gas cycle operation includes a procedure of operating the cooling fan until the pressure inside the condenser becomes lower than the pre-evaporator pressure at the start thereof. The control method according to any one of 11.   The control method according to any one of claims 8 to 13, wherein the refrigeration cycle apparatus is a vehicle air conditioner.

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