JP6704512B2 - Air conditioner, railway vehicle air conditioner, and air conditioner control method - Google Patents

Description

The present invention relates to an air conditioner, an air conditioner for a railway vehicle, and a control method for the air conditioner.

In the air conditioner, the degree of opening of the expansion valve is adjusted based on the degree of superheat calculated from the refrigerant pressure and the refrigerant temperature so that heat can be efficiently exchanged in the indoor heat exchanger, and the refrigerant flow rate is maintained at an appropriate value. ing. As the expansion valve, an electronically controlled expansion valve that can accurately control the flow rate of the refrigerant is widely used (for example, see Patent Document 1).

JP-A-10-38350 (paragraph [0023], see FIG. 2)

By the way, a capacity control mechanism for controlling the capacity of the compressor is widely applied to the air conditioner in order to adjust the cooling and heating capacity. Examples of such a capacity control mechanism include an inverter type capacity control mechanism capable of controlling the capacity of the compressor steplessly and a mechanical capacity control mechanism capable of controlling mainly in two steps.

In the air conditioner including such a capacity control mechanism, when the capacity of the compressor is changed, the suction pressure and the refrigerant pressure of the compressor fluctuate transiently. For example, when the capacity of the compressor is reduced, the refrigerant discharge amount from the compressor decreases, so that the suction pressure of the compressor increases and the refrigerant flow amount of the indoor heat exchanger temporarily increases. When the amount of refrigerant flowing through the indoor heat exchanger increases, there is a possibility that liquid refrigerant that could not be evaporated in the indoor heat exchanger will return to the compressor, causing liquid back.

As described above, the refrigerant flow rate is generally adjusted based on the degree of superheat, but various sensors used to calculate the degree of superheat have a somewhat large time constant set for the purpose of improving detection accuracy. Therefore, a time lag occurs until the influence of the change in the capacity of the compressor appears as a change in the degree of superheat. Therefore, in the method described in Patent Document 1, even if the suction pressure and the refrigerant pressure of the compressor fluctuate transiently by changing the capacity of the compressor, this fluctuation is detected as a fluctuation of the degree of superheat and the expansion valve There is a possibility that liquid back may occur before the opening degree of is changed.
In particular, such a variation is more remarkable in a compressor provided with a mechanical displacement control mechanism than in an inverter type in which the rotational speed can be finely controlled.

The present invention has been made to solve the above problems, and an air conditioner and a rail vehicle air conditioner capable of suppressing the occurrence of liquid back due to a change in the capacity of a compressor as compared with the conventional air conditioner. Aim to get.

The air conditioner according to the present invention, a compressor, an outdoor heat exchanger, an indoor heat exchanger and an electronic expansion valve the air conditioning apparatus having a refrigerant circuit connected with refrigerant pipes, the compressor an intermediate compression chamber refrigerant in the process of compression are present, a bypass passage connecting the low-pressure space in which the refrigerant of the refrigerant by Ri low pressure in the intermediate compression chambers is present, a bypass valve that opens and closes the bypass passage, overheating of the refrigerant And a control device that performs superheat degree control that sets the opening degree of the electronic expansion valve based on the degree, and the control device is based on the bypass valve being switched from the closed state to the open state. Te, the limit processing for correcting a small value by a predetermined degree of opening of the electronic expansion valve against opening that will be set by the superheat control begin, the control device, the compressor The predetermined opening degree is set based on the detection result of the pressure detecting means for detecting the pressure of the inflowing refrigerant .
An air conditioner according to the present invention is an air conditioner having a refrigerant circuit in which a compressor, an outdoor heat exchanger, an indoor heat exchanger, and an electronic expansion valve are connected by a refrigerant pipe, and the compressor is in the middle of compression. Of the intermediate compression chamber in which the refrigerant exists, a bypass passage that communicates with a low-pressure space in which a refrigerant having a lower pressure than the refrigerant in the intermediate compression chamber exists, a bypass valve that opens and closes the bypass passage, and based on the degree of superheat of the refrigerant. And a controller for performing superheat control for setting the opening degree of the electronic expansion valve, wherein the controller is based on the bypass valve being switched from a closed state to an open state. Pressure control means for starting a limiting process for correcting the opening degree of the expansion valve to a value smaller than the value set by the superheat control, and the control device detecting the pressure of the refrigerant flowing into the compressor. The condition for starting the limiting process is that the detection result of 1 is equal to or higher than the first predetermined pressure.
A control method for an air conditioner according to the present invention, a compressor, an outdoor heat exchanger, an indoor heat exchanger and a refrigerant circuit in which an electronic expansion valve is connected by a refrigerant pipe, and a refrigerant in the middle of compression of the compressor exists. A method of controlling an air conditioner comprising: a bypass passage that communicates the intermediate compression chamber with a low-pressure space in which a refrigerant having a pressure lower than that of the refrigerant in the intermediate compression chamber exists; and a bypass valve that opens and closes the bypass passage. A superheat control step of setting the opening degree of the electronic expansion valve based on the degree of superheat of the refrigerant, and the electronic expansion based on the bypass valve being switched from the closed state to the open state. A restriction step of correcting the opening degree of the valve to a value smaller than the opening degree set in the superheat degree control step by a predetermined opening degree, the predetermined opening degree of the refrigerant flowing into the compressor. It is set based on the pressure.

An air conditioner according to the present invention is an air conditioner having a refrigerant circuit in which a compressor, an outdoor heat exchanger, an indoor heat exchanger, and an electronic expansion valve are connected by a refrigerant line, and the compressor is in the middle of compression. The intermediate compression chamber in which the refrigerant exists, the bypass passage communicating with the low-pressure space in which the refrigerant having a lower pressure than the refrigerant in the intermediate compression chamber, the bypass valve opening and closing the bypass passage, and the superheat of the refrigerant and a control device for implementing the superheat degree control that sets the degree of opening of the electronic expansion valve, wherein the control unit detects the change request to switch to the closed state the bypass valve from the open state, the electronic expansion start the promotion processing for correcting to a large value by a predetermined degree the opening of the valve against the opening that will be set by the superheat degree control, then conversion cut in the closed state of the bypass valve from the open state In addition, the control device sets the predetermined opening degree based on the detection result of the pressure detection means for detecting the pressure of the refrigerant flowing into the compressor .
A control method for an air conditioner according to the present invention, a compressor, an outdoor heat exchanger, an indoor heat exchanger and a refrigerant circuit in which an electronic expansion valve is connected by a refrigerant line, and a refrigerant in the middle of compression of the compressor is present. A method for controlling an air conditioner, comprising: an intermediate compression chamber, a bypass passage communicating with a low-pressure space in which a refrigerant having a lower pressure than the refrigerant in the intermediate compression chamber exists, and a bypass valve opening and closing the bypass passage. , A superheat control step of setting the opening degree of the electronic expansion valve based on the degree of superheat of the refrigerant, and a switching request for switching the bypass valve from the open state to the closed state is detected, And an accelerating step of correcting the opening to a value larger than the opening set in the superheat control step by a predetermined opening, wherein the predetermined opening is the pressure of the refrigerant flowing into the compressor. It is set based on.

According to the present invention, the opening degree of the electronic expansion valve is corrected to a value smaller than the value set by the superheat control based on the switching of the bypass valve from the closed state to the open state. The amount of refrigerant flow can be reduced before the change in the capacity of the compressor is reflected in the change in the degree of superheat. Therefore, the occurrence of liquid back due to the change in the capacity of the compressor can be suppressed more than ever before.

When the capacity of the compressor is increased, the amount of refrigerant discharged from the compressor increases, so the amount of refrigerant in the compressor temporarily decreases. When the amount of refrigerant in the compressor decreases, the sliding portion in the compressor may directly contact and slide, which may cause a problem such as seizure. In this respect, according to the present invention, before the bypass valve is switched from the open state to the closed state, the acceleration process for correcting the opening degree of the electronic expansion valve to a value larger than the value set by the superheat control. Therefore, the amount of refrigerant stored in the compressor can be increased. Therefore, it is possible to prevent the amount of refrigerant in the compressor from rapidly decreasing due to switching the bypass valve from the open state to the closed state. Therefore, it is possible to prevent the sliding portion from directly contacting and sliding to cause a defect such as seizure.

It is a schematic diagram of the air conditioning apparatus concerning Embodiment 1 of this invention. It is a sectional view of a compressor and a capacity control mechanism concerning Embodiment 1 of the present invention. It is a control flowchart of the air conditioning apparatus concerning Embodiment 1 of this invention. 5 is a timing chart for explaining changes in the opening degree of the electronic expansion valve, the detected temperature and the set temperature, the refrigerant pressure, and the operation mode due to the limiting process and the promoting process of the air-conditioning apparatus according to Embodiment 1 of the present invention. It is a control flowchart of the air conditioning apparatus concerning Embodiment 2 of this invention. 6 is a timing chart for explaining changes in the opening degree of the electronic expansion valve, the detected temperature and the set temperature, the refrigerant pressure, and the operation mode due to the restriction process and the acceleration process of the air conditioner according to the second embodiment of the present invention. It is a control flowchart of the air conditioning apparatus concerning Embodiment 3 of this invention. It is a schematic diagram of the railway vehicle concerning Embodiment 4 of this invention. It is a side view of the compressor concerning Embodiment 4 of the present invention. It is a schematic diagram of the air conditioning apparatus concerning other embodiment of this invention.

Embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and the duplicate description thereof will be appropriately simplified or omitted. Further, for convenience of description, the proportional relationship between the size and shape of the parts shown in each drawing may be exaggerated.

(Embodiment 1)
The air conditioning apparatus 10 according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 4. As shown in FIG. 1, an air conditioner 10 according to the present embodiment functions as a compressor 1 that compresses a refrigerant, an electronic expansion valve 2 that depressurizes the refrigerant, and a condenser during cooling operation, and the outdoor unit. An outdoor heat exchanger 3 for exchanging heat between air and refrigerant, an indoor heat exchanger 4 for exchanging heat between indoor air and refrigerant during cooling operation, and a controller 7 for controlling these. Have and. The controller 7 is connected to a room temperature sensor 14 that measures the temperature of the room in which the air conditioner 10 is installed, and a remote controller 15 that allows the user to perform on/off control of the air conditioner 10 and input a desired set temperature To. There is.

The compressor 1 compresses the sucked refrigerant, discharges it in a high temperature/high pressure state. The compressor 1 in the present embodiment is composed of a scroll compressor including a mechanical capacity control mechanism 60, and is operated at a predetermined fixed number of compressions per unit time (second). Details of the capacity control mechanism 60 will be described later.

The outdoor heat exchanger 3 is a heat exchanger for the outside air that exchanges heat between the outside air taken from the outside and the refrigerant, and transfers heat from the refrigerant to the outside air during cooling.
The indoor heat exchanger 4 is an indoor heat exchanger that performs heat exchange between the indoor air and the refrigerant, and transfers heat from the indoor air to the refrigerant during cooling.

The electronic expansion valve 2 decompresses and expands the refrigerant to obtain a low-temperature low-pressure refrigerant, and is composed of an expansion valve whose opening can be variably controlled. Preferably, an electronic linear expansion valve (LEV) is used.

The compressor 1, the outdoor heat exchanger 3, the electronic expansion valve 2, and the indoor heat exchanger 4 are connected by a refrigerant pipe line 20 through which a refrigerant flows, and form a refrigerant circuit in which the refrigerant circulates. During the cooling operation, the refrigerant circulates in the refrigerant pipeline 20 in the direction indicated by the solid arrow in FIG. The refrigerant is compressed in the compressor 1 into a high-temperature and high-pressure gaseous state, condensed and liquefied in the outdoor heat exchanger 3, expanded in the electronic expansion valve 2, and decompressed into a low-temperature low-pressure two-phase state, The indoor heat exchanger 4 evaporates and gasifies and returns to the compressor 1. When the indoor air passes through the indoor heat exchanger 4, it exchanges heat with a low-temperature refrigerant to become low-temperature air and is supplied to the room.

In the refrigerant line 20, the line connecting the compressor 1, the outdoor heat exchanger 3 and the electronic expansion valve 2 is a high-pressure refrigerant line 26 through which the high-pressure refrigerant flowing out of the compressor 1 flows. Further, the pipeline connecting the electronic expansion valve 2, the indoor heat exchanger 4 and the compressor 1 is a low pressure refrigerant pipeline 25 through which a refrigerant having a lower pressure than the high pressure refrigerant pipeline 26 flows.
A high pressure control refrigerant passage 21 into which a part of the high pressure refrigerant discharged from the compressor 1 flows is connected to the high pressure refrigerant pipe line 26. On the other hand, the low-pressure refrigerant conduit 25 is connected to the low-pressure control refrigerant passage 22 into which a part of the low-pressure refrigerant drawn into the compressor 1 flows. The high pressure control refrigerant passage 21 and the low pressure control refrigerant passage 22 are connected to a control pressure introducing pipe 23 that communicates with the capacity control mechanism 60.

The high pressure control refrigerant passage 21 is provided with a high pressure control valve 8, and the low pressure control refrigerant passage 22 is provided with a low pressure control valve 9. Each of the high pressure control valve 8 and the low pressure control valve 9 is an electromagnetic valve capable of switching between circulation and non-circulation of the refrigerant.
The high-pressure control valve 8 and the low-pressure control valve 9 are both connected to the control device 7, and their opening and closing are performed based on a command from the control device 7. The controller 7 opens one of the high pressure control valve 8 and the low pressure control valve 9 and closes the other. When the high pressure control valve 8 is closed and the low pressure control valve 9 is opened, a part of the low pressure refrigerant flowing through the low pressure refrigerant conduit 25 flows into the control pressure introducing pipe 23. On the other hand, when the high pressure control valve 8 is opened and the low pressure control valve 9 is closed, a part of the high pressure refrigerant flowing through the high pressure refrigerant conduit 26 flows into the control pressure introduction pipe 23.

Next, the configuration of the compressor 1 according to the present embodiment and the capacity control mechanism 60 included in the compressor 1 will be described in detail with reference to FIGS. 1 and 2.
As shown in FIG. 2, the compressor 1 has a hermetic container 50 that forms the outer shell of the compressor 1. Further, the compressor 1 includes a fixed scroll 51 provided with a fixed scroll 54 as a sliding portion for compressing a refrigerant inside a closed container 50, and a swing scroll 52 provided with a swing scroll 55. Equipped with. The fixed spiral body 54 and the rocking spiral body 55 are combined so as to mesh with each other, and the fixed spiral body 54 and the rocking spiral body 55 thus combined form a plurality of compression chambers P. The compression chamber P at the center communicates with the high pressure refrigerant pipe line 26.

The swing scroll 52 swings with respect to the fixed scroll 51 at a predetermined constant speed, and gradually reduces the compression chamber P from the outer low pressure compression chamber to the inner high pressure compression chamber. The refrigerant flowing into the compression chamber 1 from the low-pressure refrigerant pipe 25 flows into the compression chamber P from the low-pressure compression chamber outside the compression chamber P as shown by the solid line arrow in FIG. 2, and is accompanied by the rocking of the rocking scroll 52. While being compressed, it goes to the inner high-pressure compression chamber. Then, it is discharged to the high-pressure refrigerant pipe 26 through the discharge passage 53.

The fixed scroll 51 is provided with a capacity control mechanism 60 that controls the capacity of the compressor 1. The capacity control mechanism 60 includes a back pressure passage 61 into which either the low pressure refrigerant or the high pressure refrigerant flows from the control pressure introduction pipe 23, a back pressure chamber 62 that accommodates a bypass valve 64 and communicates with the back pressure passage 61, and a bypass. A coil spring 63 that elastically supports the valve 64 and a bypass passage 65 that is provided in the fixed scroll 51 and that returns the refrigerant in the intermediate compression chamber in the process of compression to the low pressure space are configured. This intermediate compression chamber is arbitrarily determined by the position where the bypass passage 65 is formed. The low-pressure space is an arbitrary space in the internal space of the compressor 1 in which a refrigerant having a lower pressure than the intermediate compression chamber exists. It may be outside the compression chamber P or may be a low pressure compression chamber outside the intermediate compression chamber. In the present embodiment, the coil spring 63 elastically supports the bypass valve 64, but another elastic body such as a rubber member may be used instead.

The refrigerant pressure in the control pressure introducing pipe 23 and the refrigerant pressure in the intermediate compression chamber act on the bypass valve 64 described above. When the low-pressure refrigerant flows into the back pressure passage 61, the refrigerant pressure in the control pressure introducing pipe 23 becomes lower than the refrigerant pressure in the intermediate compression chamber, and the bypass valve 64 opens. In this case, a part of the refrigerant in the intermediate compression chamber is returned to the low pressure space through the bypass passage 65. In this way, the operation mode in which the bypass valve 64 is opened and a part of the refrigerant in the intermediate compression chamber is returned to the low pressure space is referred to as an unload mode (UL).

On the other hand, when the high pressure refrigerant flows into the back pressure passage 61, the refrigerant pressure in the control pressure introducing pipe 23 becomes higher than the refrigerant pressure in the intermediate compression chamber, and the bypass valve 64 closes. In this case, all the refrigerant in the intermediate compression chamber is transferred to the high pressure compression chamber, compressed, and then discharged to the discharge passage 53. In this way, the operation mode in which the bypass valve 64 is closed and all the refrigerant in the intermediate compression chamber is discharged to the discharge passage 53 is set to the full load mode (FL).

Returning to FIG. 1, the description will be continued. The low-pressure refrigerant pipe 25 is provided with a refrigerant temperature sensor 11 for detecting the refrigerant temperature Tm of the refrigerant sucked into the compressor 1 and a refrigerant pressure sensor 12 (pressure detecting means in claims) for detecting the refrigerant pressure Pm. Has been. The refrigerant temperature sensor 11, the refrigerant pressure sensor 12, the high pressure control valve 8, the low pressure control valve 9, the electronic expansion valve 2, the room temperature sensor 14, and the remote controller 15 are connected to the control device 7.

The control device 7 includes a CPU, a ROM, a RAM, and the like (not shown), and stores various programs for driving the air conditioning apparatus 10, functions, fixed data, and the like. The control device 7 executes various programs by using these functions and data, data input from various sensors, and the like, opens and closes the high pressure control valve 8 and the low pressure control valve 9, and opens the electronic expansion valve 2. The degree adjustment and other drive processing of the air conditioning apparatus 10 are performed.

For example, the control device 7 calculates the superheat degree SH1 of the refrigerant flowing into the compressor 1 from the refrigerant temperature Tm detected by the refrigerant temperature sensor 11 and the refrigerant pressure Pm detected by the refrigerant pressure sensor 12, and this calculation is performed. The opening degree of the electronic expansion valve 2 is adjusted based on the superheat degree SH1.

The control device 7 compares the calculated superheat degree SH1 with a threshold value SHT stored in advance, and adjusts the opening degree of the electronic expansion valve 2 according to the difference between the superheat degree SH1 and the threshold value SHT. When the superheat degree SH1 is larger than the threshold value SHT, the larger the difference between the superheat degree SH1 and the threshold value SHT, the larger the opening degree of the electronic expansion valve 2 and the smaller the superheat degree SH1. When the superheat degree SH1 is smaller than the threshold value SHT, the larger the difference between the superheat degree SH1 and the threshold value SHT, the smaller the opening degree of the electronic expansion valve 2 and the larger the superheat degree SH1. When SH1 is equal to the threshold value SHT, the opening degree of the electronic expansion valve 2 is not changed. The threshold SHT is generally set to 5 to 10°C, but is not limited to this.

Further, the control device 7 calculates the deviation ΔT between the detected temperature Tr of the room temperature sensor 14 and the set temperature To set by the user through the remote controller 15 using the following equation (1), and compresses based on this deviation ΔT. Determine the operating mode of machine 1.

ΔT=Tr−To (1)

The control device 7 stores the upper limit value Tu and the lower limit value Tl of the deviation ΔT, and drives the compressor 1 in the full load mode when it determines that the deviation ΔT is equal to or larger than the upper limit value Tu. On the other hand, when it is determined that the deviation ΔT is less than the lower limit value Tl, the compressor 1 is driven in the unload mode. On the other hand, when the deviation ΔT is greater than or equal to the lower limit value Tl and less than the upper limit value Tu, the operation mode is not switched and the air conditioner 10 is driven in the current operation mode.

By the way, when the bypass valve 64 is switched from the closed state to the open state in order to switch the operation mode from the full load mode to the unload mode, the refrigerant discharge amount from the compressor 1 is rapidly reduced. The flow rate of refrigerant temporarily increases rapidly. Since the refrigerant temperature sensor 11 and the refrigerant pressure sensor 12 are set to have a relatively large time constant for the purpose of accurately detecting the superheat degree SH1, the influence of the change in the refrigerant flow amount due to the change of the operation mode is influenced by the superheat degree. There is a time lag until it appears as a change in SH1. When such a time lag occurs, the refrigerant flow amount of the low-pressure refrigerant pipe 25 exceeds the heat exchange capacity of the indoor heat exchanger 4 before the change of the refrigerant flow amount is detected as the change of the superheat degree SH1. There is a possibility that a so-called liquid bag may be generated in which a part of the refrigerant increases and flows into the compressor 1 without evaporating.

Therefore, in the present embodiment, the operation mode of the compressor 1 is switched from the full load mode to the unload mode, that is, the bypass valve 64 is switched from the closed state to the open state. The control device 7 starts the limiting process of subtracting and correcting the opening degree of the electronic expansion valve 2 to the opening degree smaller than the opening degree set based on the superheat degree SH1 by the predetermined opening degree θa. It should be noted that the predetermined opening degree θa is an opening degree required to suppress an increase in the refrigerant flow amount due to switching the bypass valve 64 from the closed state to the open state, and is set arbitrarily. The opening of the electronic control valve 2 after the subtraction correction by the predetermined opening θa may be set to a value that allows the amount of refrigerant to pass through which corresponds to the lower limit of the heat exchange capacity of the indoor heat exchanger 4. Preferred, but not limited to this. However, if the predetermined opening degree θa is too large, the pressure of the refrigerant in the compressor 1 is suddenly reduced, and the fixed spiral body 54 and the swinging spiral body 55 may come into direct contact sliding with each other without interposing the refrigerant, and a problem such as seizure may occur. There is. Therefore, the predetermined opening degree θa is more preferably set in consideration of the amount of refrigerant in the compressor 1.

On the other hand, in order to switch the operation mode from the unload mode to the full load mode, when the bypass valve 64 is switched from the open state to the closed state, the refrigerant suction amount of the compressor 1 does not change, but the compression amount is reduced. Since the refrigerant discharge amount from the machine 1 temporarily increases rapidly, the refrigerant amount in the compressor 1 temporarily decreases rapidly. If the amount of the refrigerant in the compressor 1 is suddenly reduced, the fixed spiral body 54 and the swinging spiral body 55 may directly contact and slide with each other without using the refrigerant, and a problem such as seizure may occur.

Therefore, when the control device 7 detects a request to switch from the unload mode to the full load mode, that is, when the deviation ΔT becomes equal to or larger than the upper limit value Tu when the operation mode is the unload mode, After performing an acceleration process of correcting the opening degree of the electronic expansion valve 2 by adding the predetermined opening degree θb to the opening degree set based on the superheat degree SH1, the operation mode of the compressor 1 is switched to the full load mode. .. The predetermined opening degree θb is an opening degree necessary for suppressing a sharp decrease in the amount of refrigerant in the compressor 1 caused by switching the bypass valve 64 from the open state to the closed state, and is set arbitrarily. For example, the opening degree of the electronic control valve 2 after the addition and correction of the predetermined opening degree θb is set to a value that allows the refrigerant to pass through an amount corresponding to the upper limit of the heat exchange capacity of the indoor heat exchanger 4. However, it is not limited to this.

Next, the operation of the air conditioner 10 in the present embodiment will be described with reference to the flowchart in FIG. Note that the control device 7 calculates the superheat degree SH1 based on the refrigerant temperature Tm detected by the refrigerant temperature sensor 11 and the refrigerant pressure Pm detected by the refrigerant pressure sensor 12, in parallel with the flowchart of FIG. It is assumed that the appropriate opening degree of the electronic expansion valve 2 is constantly calculated based on the superheat degree SH1.
First, when the user operates the remote controller 15 to execute ON control of the air conditioning apparatus 10, the compressor 1 starts driving. By driving the compressor 1, the operation by the air conditioner 10 is started.
When the drive of the compressor 1 is started, the control device 7 first calculates the deviation (ΔT) between the detected temperature Tr of the room temperature sensor 14 and the set temperature To input by the user based on the above equation (1). (Step S10).

Next, the control device 7 determines whether the calculated deviation ΔT is equal to or larger than the upper limit value Tu stored in advance (step S11). When it is determined that the deviation ΔT is less than the upper limit value Tu (step S11; NO), it is determined whether the deviation ΔT is less than the lower limit value Tl (step S12).
When it is determined that the deviation ΔT is not less than the lower limit value Tl (step S12; NO), that is, when the deviation ΔT is less than the upper limit value Tu and not less than the lower limit value Tl, the operation mode of the compressor 1 is changed. Absent. In this case, the control device 7 does not perform the opening degree correction of the electronic expansion valve 2.

On the other hand, when determining that the deviation ΔT is less than the lower limit value Tl (step S12; YES), the control device 7 switches the operation mode of the compressor 1 to the unload mode. First, the control device 7 determines whether the operation mode of the compressor 1 is the full load mode (step S13).

In the present embodiment, when the low pressure control valve 9 is open and the high pressure control valve 8 is closed, the bypass valve 64 is in the open state, so that the compressor 1 is in the unload mode. to decide. On the other hand, when the low-pressure control valve 9 is closed and the high-pressure control valve 8 is open, the bypass valve 64 is in the closed state, so the compressor 1 is determined to be in the full load mode. In this embodiment, whether the compressor 1 is in the unload mode or the full load mode is determined by determining which of the low pressure control valve 9 and the high pressure control valve 8 is open. However, the determination of the operation mode of the compressor 1 can also be performed by using another known method. For example, the determination may be made based on the refrigerant pressure Pm of the control pressure introducing pipe 23, or a sensor that detects the opening/closing of the bypass valve 64 may be used, but the method is not limited to these methods, and other known methods may be used. Can be used.

When it is determined that the operation mode of the compressor 1 is not the full load mode (step S13; NO), that is, when the compressor 1 is in the unload mode, the operation mode is not changed and the electronic expansion is performed. The opening degree of the valve 2 is not corrected.

On the other hand, when determining that the operation mode of the compressor 1 is the full load mode (step S13; YES), the control device 7 switches the operation mode of the compressor 1 to the unload mode (step S14), and performs the limiting process. Start (step S15). When the restriction process is started, the control device 7 performs the opening correction by subtracting the above-described predetermined opening θa from the opening of the electronic expansion valve 2 calculated based on the superheat degree SH1 to perform the electronic expansion. The opening of the valve 2 is set to the corrected opening.

Next, the control device 7 determines whether the elapsed period Ta from the start of the limiting process is the predetermined period T1 or more (step S16). The predetermined period T1 is a period sufficient for the refrigerant pressure Pm to decrease, and is set arbitrarily. For example, the period required for the amount of refrigerant corresponding to the amount of the refrigerant returned from the intermediate compression chamber to the low pressure space to pass through the electronic control valve 2 is preferable, but it is not limited to this.

When it is determined that the elapsed period Ta is less than the predetermined period T1 (step S16; NO), the limiting process is continued, and when it is determined that the elapsed period Ta is equal to or more than the predetermined period T1 (step S16; YES), the limiting process is performed. Is finished (step S17). That is, the opening degree correction of the electronic expansion valve 2 is completed.

On the other hand, when it is determined that the deviation ΔT is equal to or greater than the upper limit value Tu (step S11; YES), it is determined whether the compressor 1 is in the unload mode by the method described above (step S18).

When it is determined that the compressor 1 is in the unload mode (step S18; YES), the control device 7 determines that the deviation ΔT is equal to or larger than the upper limit value Tu and the operation mode is in the unload mode. It is determined that there is a switching request to switch from unload mode to full load mode.

At this time, the control device 7 starts the acceleration process before switching the operation mode to the full load mode (step S19). When the acceleration process is started, the control device 7 performs an opening degree correction to add the above-described predetermined opening degree θb to the opening degree of the electronic expansion valve 2 calculated based on the superheat degree SH1, The opening of the expansion valve 2 is set to the corrected opening.

Next, the control device 7 determines whether or not the elapsed period Tb from the start of the promotion process is the predetermined period T2 or more (step S20). The predetermined time period T2 is necessary to secure a sufficient amount of refrigerant in the compressor 1 that does not cause a problem in the compressor 1 even if the refrigerant discharge amount from the compressor 1 rapidly increases due to a change in the operation mode. The period, which is set arbitrarily. For example, it is preferable that the period required to store the refrigerant in the compression chamber 1 in an amount corresponding to the amount of the refrigerant returned from the intermediate compression chamber to the low pressure space is not limited to this.

When it is determined that the elapsed period Tb is less than the predetermined period T2 (step S20; NO), the promotion process is continued, and when it is determined that the elapsed period Tb is equal to or greater than the predetermined period T2 (step S20; YES), the promotion process. Is finished (step S21). That is, the opening degree correction of the electronic expansion valve 2 is completed. Further, the operation mode of the compressor 1 is switched to the full load mode (step S21).

On the other hand, when it is determined that the compressor 1 is not in the unload mode (step S18; NO), that is, when the compressor 1 is in the full load mode, the operation mode of the compressor 1 is not changed. In this case, the controller 7 does not correct the opening degree of the electronic expansion valve 2.
Next, the control device 7 determines whether or not the operation of the air conditioner 10 has ended (step S22). When determining that the operation of the air conditioner 10 has ended (step S22; YES), the control device 7 ends this processing and determines that the operation of the air conditioner 10 is continuing (step S22; NO), and returns to step S10 to continue this process.

4, (a) the opening degree of the electronic expansion valve 2, (b) the detected temperature Tr and the set temperature To of the room temperature sensor 14, and (c) the refrigerant pressure sensor 12 when the processing described in FIG. 3 is performed. One example of each transition of the refrigerant pressure Pm detected in step (d) and the operation mode of the compressor (d) will be shown.

In FIG. 4A, a solid line shows an example of the transition of the opening degree of the electronic expansion valve 2 when the restriction process and the acceleration process described above are performed, and in the case where the restriction process and the acceleration process described above are not performed. An example of transition of the opening degree of the electronic expansion valve 2 is shown by a two-dot chain line. In FIG. 4B, an example of the transition of the set temperature To set by the user through the remote controller 15 is shown by a solid line, and an example of the transition of the temperature Tr detected by the room temperature sensor 14 is shown by a dashed line. In FIG. 4(c), an example of the transition of the refrigerant pressure Pm in the case where the above-mentioned restriction process and promotion process are performed is shown by a solid line, and the transition of the refrigerant pressure Pm in the case where the above-mentioned restriction process and promotion process are not performed An example is shown by a chain double-dashed line. In FIG. 4D, a solid line shows an example of the transition of the operation mode of the compressor 1 when the above-described restriction processing and acceleration processing are performed, and the compressor when the above-described restriction processing and acceleration processing is not performed. An example of transition of the operation mode of No. 1 is shown by a two-dot chain line.

As shown in FIG. 4, when the deviation ΔT between the set temperature To and the detected temperature Tr is not less than the upper limit value Tu, the compressor 1 is operated in the full load mode (timing t0 to t1).

When the deviation ΔT becomes smaller than the upper limit value Tu and further becomes smaller than the lower limit value Tl, the control device 7 switches the operation mode of the compressor 1 from the full load mode to the unload mode. At this time, the control device 7 starts the limiting process of subtracting the predetermined angle θa from the opening degree of the electronic expansion valve 2 calculated based on the superheat degree SH1 (timing t1). This restriction process continues for a predetermined period T1 (timing t1 to t2).

When the limiting process is performed, the opening amount of the electronic expansion valve 2 decreases and the amount of the refrigerant flowing through the low-pressure refrigerant pipe 25 decreases, so that the temporary increase in the refrigerant pressure Pm is suppressed. .. When the predetermined period T1 has elapsed, the control device 7 ends the limiting process (timing t2).

After that, when the set temperature To is changed and the deviation ΔT becomes equal to or larger than the upper limit value Tu (timing t3), the control device 7 determines that there is a request for switching the operation mode.
In this case, the control device 7 sets the opening degree of the electronic expansion valve 2 to the predetermined opening degree θb with respect to the opening degree calculated from the superheat degree SH1 before switching the operation mode from the unload mode to the full load mode. A promotion process for addition correction is started (timing t3). This promotion process continues for a predetermined period T2 (timing t3 to t4). During this time, the operation mode is maintained in the unload mode.

When the acceleration process is performed, the amount of the refrigerant flowing through the low-pressure refrigerant pipe line 25 increases as the opening degree of the electronic expansion valve 2 increases, so that the refrigerant pressure Pm increases (timing t3 to t4). When the predetermined period T2 has elapsed, the control device 7 ends the promotion process (timing t4). That is, the control device 7 ends the opening degree correction of the electronic expansion valve 2. Further, the control device 7 switches the operation mode of the compressor 1 from the unload mode to the full load mode.

According to the above described first embodiment, the following effects can be obtained.

The capacity of the compressor 1 is reduced to start the limiting process of subtracting the predetermined opening θa from the opening of the electronic expansion valve 2 based on the switching of the bypass valve 64 from the closed state to the open state. The refrigerant flow rate can be reduced before the change is reflected in the change in the superheat degree SH1. Therefore, the occurrence of liquid back due to the change in the capacity of the compressor 1 can be suppressed more than ever before.

Before the bypass valve 64 is switched from the open state to the closed state, the acceleration process of adding and correcting the predetermined opening degree θb to the opening degree of the electronic expansion valve 2 is started, so that the capacity of the compressor 1 is not changed. In addition, the amount of refrigerant stored in the compressor 1 can be increased. Therefore, it is possible to prevent the amount of the refrigerant in the compressor 1 from suddenly decreasing and the fixed spiral body 54 and the swinging spiral body 55 to directly contact and slide without the intermediary of the refrigerant.

Since the limiting process is performed for the predetermined period T1, the occurrence of hunting can be suppressed, and the occurrence of liquid back can be suppressed more preferably.

Since the acceleration process is performed for the predetermined period T2, it is possible to suppress the occurrence of hunting and more preferably suppress the direct contact and sliding of the fixed spiral body 54 and the swing spiral body 55.

(Embodiment 2)
A control method of the air-conditioning apparatus 10 according to the second embodiment will be described with reference to FIGS. 1 to 4 and FIGS. It should be noted that, unless otherwise specified, the same reference numerals indicate the same configurations, and the same processes as those in the first embodiment are denoted by the same step numbers, and the detailed description thereof will be appropriately omitted.

FIG. 5 is a control flowchart of the air conditioner 10 according to the second embodiment. The operation of the control device 7 according to the second embodiment will be described with reference to FIG. The control flowchart shown in FIG. 5 is obtained by replacing steps S15 to 17 of the flowchart of FIG. 3 with steps S30 to S34, and the other steps are the same. Therefore, description of similar control contents is omitted.

The controller 7 switches the operation mode of the compressor 1 to the unload mode (step S14), and then the refrigerant pressure Pm detected by the refrigerant pressure sensor 12 is equal to or higher than the threshold value P1 (first predetermined pressure in claims). Or not (step S30). The threshold value P1 is preferably the refrigerant pressure when the amount of refrigerant corresponding to the upper limit of the heat exchange capacity of the indoor heat exchanger 4 passes.

When determining that the refrigerant pressure Pm is less than the threshold value P1 (step S30; NO), the control device 7 determines whether or not the elapsed period Tc after switching the operation mode to the unload mode is the predetermined period T3 or more. Yes (step S31). The predetermined period T3 is a period required to return the temporarily increased suction pressure to the steady state after switching the operation mode of the compressor 1 to the unload mode, and is set arbitrarily. It is preferable to set the period in which the amount of the refrigerant corresponding to the amount of the refrigerant returned from the intermediate compression chamber to the low pressure space passes through the electronic control valve 2, but not limited to this.

When it is determined that the elapsed period Tc after switching to the unload mode is less than the predetermined period T3 (step S31; NO), the process returns to step S30. On the other hand, when it is determined that the elapsed period Tc after switching to the unload mode is the predetermined period T3 or more (step S31; YES), this process is temporarily terminated.

On the other hand, when it is determined that the refrigerant pressure Pm is equal to or higher than the threshold value P1 (step S30; YES), the limiting process is started (step S32). Then, it is determined whether or not the elapsed period Ta after the start of the limiting process is equal to or longer than the predetermined period T1 (step S33), and it is determined that the elapsed period Ta after the start of the limiting process is equal to or larger than the predetermined period T1 (step S33; NO). ), the process returns to step S33, and when it is determined that the elapsed period Ta after the start of the restriction process is equal to or longer than the predetermined period 1 (step S33; YES), the restriction process ends (step S34).

6, (a) the opening degree of the electronic expansion valve 2, (b) the detected temperature Tr and the set temperature To of the room temperature sensor 14, and (c) the refrigerant pressure sensor 12 when the processing described in FIG. 5 is performed. One example of each transition of the refrigerant pressure Pm detected in step (d) and the operation mode of the compressor (d) will be shown.

In FIG. 6A, an example of the transition of the opening degree of the electronic expansion valve 2 when the restriction process and the acceleration process described above are performed is shown by a solid line, and when the restriction process and the acceleration process described above are not performed. An example of transition of the opening degree of the electronic expansion valve 2 is shown by a two-dot chain line. In FIG. 6B, an example of the transition of the set temperature To set by the user through the remote controller 15 is shown by a solid line, and an example of the transition of the detected temperature Tr by the room temperature sensor 14 is shown by a dashed line. In FIG. 6(c), an example of the transition of the refrigerant pressure Pm in the case where the above-mentioned restriction process and the acceleration process are carried out is shown by a solid line, and the transition of the refrigerant pressure Pm in the case where the above-mentioned restriction process and the acceleration process are not carried out. An example is shown by a chain double-dashed line. In FIG. 6D, an example of the transition of the operation mode of the compressor 1 when the above-described restriction process and acceleration process are performed is shown by a solid line, and the compressor when the above-mentioned restriction process and acceleration process are not performed is shown. An example of transition of the operation mode of No. 1 is shown by a two-dot chain line.

As shown in FIG. 6, when the compressor 1 is operated in the full load mode (timing t0 to t1) and then the operation mode is switched from the full load mode to the unload mode (timing t1), the control device 7 is activated. , The refrigerant pressure Pm is monitored over a predetermined period T3 (timing t1 to t7). When the refrigerant pressure Pm becomes equal to or higher than the threshold value P1, the control device 7 starts the limiting process of subtracting and correcting the predetermined opening degree θa with respect to the opening degree of the electronic expansion valve 2 calculated based on the superheat degree SH1 (timing. t5). This restriction process continues for a predetermined period T1 (timing t5 to t6).

In addition to the same effects as the effects described in the first embodiment, the present embodiment has the following effects.

When the refrigerant pressure Pm is determined to be equal to or higher than the threshold P1, the limiting process is started, and when the refrigerant pressure Pm is determined to be less than the threshold P1, the limiting process is not started. Therefore, it is possible to prevent the restriction process from being started and the amount of the circulating refrigerant to be excessively reduced even though the refrigerant pressure P is sufficiently low. Therefore, it is possible to suppress a decrease in cooling capacity.

(Embodiment 3)
A control method of the air-conditioning apparatus 10 according to the third embodiment will be described with reference to FIGS. It should be noted that, unless otherwise specified, the same reference numerals indicate the same configurations, and the same processes as those in the first embodiment are denoted by the same step numbers, and the detailed description thereof will be appropriately omitted.

FIG. 7 is an explanatory diagram of a control flowchart of the air-conditioning apparatus 10 according to the third embodiment. The operation of the control device 7 according to the third embodiment will be described with reference to FIG. 7. The control flowchart shown in FIG. 7 is obtained by adding processing (steps S1 to S3) at the time of starting the air conditioning apparatus 10 to the flowchart of FIG. 3, and the other steps are the same. Therefore, description of similar control contents is omitted.

When the air conditioner 10 is started, the refrigerant in the compressor 1 is in a low temperature state, so that the refrigerant easily dissolves in the lubricating oil of the compressor 1. If a large amount of the refrigerant is dissolved in the lubricating oil in the compressor 1, the pressure inside the compressor 1 is reduced when the compressor 1 is started, which may cause so-called oil forming in which the refrigerant in the lubricating oil is rapidly evaporated. is there. When oil forming occurs, the foamed lubricating oil in the compressor 1 may be discharged to the outside of the compressor 1.

Therefore, in the present embodiment, when the air conditioner 10 is started, the opening degree of the electronic expansion valve 2 is fixed to a predetermined opening degree θc (starting opening degree in claims), so that the compressor at the time of starting is fixed. The amount of refrigerant flowing into the compressor 1 is increased, and the decrease in the pressure inside the compressor 1 is suppressed. In addition, the operation mode of the compressor 1 when the air conditioner 10 is started is set to the unload mode, and the refrigerant discharge amount from the compressor 1 is reduced, so that the reduction in the pressure in the compressor 1 is more preferably suppressed. ..

The process at the time of starting the air conditioning apparatus 10 in the present embodiment will be described with reference to FIG. 7. When the operation of the compressor 1 is started and the operation of the air conditioner 10 is started, the control device 7 fixes the opening degree of the electronic expansion valve 2 to a predetermined opening degree θc (step S1). .. The predetermined opening degree θc supplies the refrigerant in an amount such that oil forming does not occur even if the inside of the compressor 1 is depressurized by discharging the refrigerant from the compressor 1 when the compressor 1 is started. It is the opening required for, and is set arbitrarily. Most preferably, it is the maximum opening that the electronic expansion valve 2 can take.

Next, the controller 7 sets the operation mode of the compressor 1 to the unload mode (step S2). After that, the control device 7 determines whether or not the elapsed period Td from the start of the operation of the air conditioner 10 is the predetermined period T4 or more (step S3). The predetermined period T4 is a period required to complete the start-up of the air conditioner 10 and transition to the steady state. For example, after the air conditioner 10 is started, the period required for the superheat degree SH1 to converge to a certain range is obtained in advance and measured, and this period can be set as the predetermined period T4. Alternatively, the period until the refrigerant discharged from the compressor 1 circulates in the refrigerant pipe 20 and returns to the compressor 1 again can be measured in advance, and this period can be set as the predetermined period T4.

When it is determined that the elapsed period Td from the start of the operation of the air conditioner 10 is less than the predetermined period T4 (step S3; NO), the process returns to step S3. On the other hand, when it is determined that the elapsed period Td from the start of the operation of the air conditioner 10 is the predetermined period T4 or more (step S3; YES), the process proceeds to step S10.

In addition to the same effects as those described in the first and second embodiments, the present embodiment has the following effects.
When the air conditioner 10 is started, the opening degree of the electronic expansion valve 2 is fixed to the predetermined opening degree θc, and the operation mode of the compressor 1 is set to the unload mode. The pressure drop in the machine 1 can be suppressed. Therefore, it is possible to suppress the occurrence of the liquid bag and the oil forming when the air conditioner 10 is started.

(Embodiment 4)
The air conditioning apparatus 10 according to the fourth embodiment will be described with reference to FIGS. 8 and 9. In this Embodiment 4, an example in which the air-conditioning apparatus 10 described in Embodiment 1 or 2 is applied to a railway vehicle will be described. It should be noted that, unless otherwise specified, the same reference numerals indicate the same configurations, and the same steps as those in the first or second embodiment are denoted by the same step numbers, and the detailed description thereof will be appropriately omitted.
FIG. 8 shows an external view of a vehicle 70 equipped with the air conditioning apparatus 10 according to the present embodiment. Although FIG. 8 shows the case where the air conditioning apparatus 10 is installed on the roof of the vehicle, the air conditioning apparatus 10 may be installed under the floor of the vehicle.

As shown in FIG. 9, in the present embodiment, the compressor 1 is disposed with the discharge side facing upward so that the axial center is inclined at an inclination angle A with respect to the horizontal plane. The inclination angle A is preferably 0° to 15°, more preferably 0° to 10°, and most preferably 0° to 5°.

When installing the air conditioner 10 on a railroad vehicle, there are many cases where the space to install the air conditioner 10 is limited, and there is particularly no space in the height direction. Therefore, it is required to reduce the height of the air conditioner 10.

On the other hand, inside the compressor 1, the lubricating oil 31 that lubricates the fixed spiral body 54, the swing spiral body 55, and the like is stored. When the axial center of the compressor 1 is installed parallel to the horizontal plane in order to achieve a low profile, the lubricating oil 31 may flow out into the refrigerant conduit 20 together with the compressed refrigerant. Further, when liquid back occurs, similarly, the lubricating oil 31 may flow out to the refrigerant pipeline 20.

In this respect, in the present embodiment, since the axial center of the compressor 1 is arranged so as to be inclined at the inclination angle A with respect to the horizontal plane, the outflow of lubricating oil is greater than that in the case where the compressor 1 is installed parallel to the horizontal plane. Can be suppressed. Further, as described in each of the first to third embodiments, since the occurrence of liquid back can be suppressed through the control of the electronic control valve 2, the outflow of lubricating oil can be suppressed appropriately.

In addition to the same effects as the effects described in the first to third embodiments, the present embodiment has the following effects.
-According to the present embodiment, it is possible to reduce the height of the air conditioner 1 and suppress the outflow of the lubricating oil 31.

(Other embodiments)
As shown in FIG. 10, the air conditioner 10 according to the present embodiment includes an accumulator 28 provided in the middle of a refrigerant pipe 20 connecting the indoor heat exchanger 4 to the compressor 1, and a four-way refrigerant flow path. A valve 29, a hot gas bypass 27 that bypasses the refrigerant discharged from the compressor 1 to the inflow side of the compressor 1, and an electromagnetic valve 32 that switches between circulation and non-circulation of the hot gas bypass passage 27 are provided. You can

In the present embodiment, during heating operation, the refrigerant is compressed by the compressor 1 into a high-temperature and high-pressure gaseous state by switching the four-way valve 29, condensed and liquefied in the indoor heat exchanger 4, and then the electronic expansion valve. It is expanded in 2 and reduced in pressure to become a low temperature and low pressure two-phase state, which is vaporized into gas in the outdoor heat exchanger 3 and returned to the compressor 1 through the accumulator 28. When the vehicle interior air passes through the indoor heat exchanger, it exchanges heat with the high temperature refrigerant, becomes high temperature air, and is supplied into the vehicle interior. As described above, only the flow direction of the refrigerant in the refrigerant circuit is different between the cooling time and the heating time, and the configuration and operation are the same.

According to the present embodiment, even when the lubricating oil flows out of the compressor 1, the lubricating oil flows through the hot gas bypass passage 27 and flows into the compressor 1 again, so that the lubricating oil in the compressor 1 is exhausted. Can be suppressed. Further, since the liquid refrigerant is stored in the accumulator, the occurrence of liquid back can be suppressed more effectively.

In each of the above-described embodiments, the value obtained by subtracting the set temperature To from the detected temperature Tr is set as ΔT, but in the present embodiment, the absolute value of the value obtained by subtracting the set temperature To from the detected temperature Tr is defined as the deviation ΔT. Preferably.

In each of the above embodiments, the high pressure control valve 8 and the low pressure control valve 9 are electromagnetic valves that switch between flowing and non-circulating the refrigerant, but the present invention is not limited to this. For example, the high pressure control valve 8 and the low pressure control valve 9 may be linear valves that are electrically operated valves that can adjust the opening.

In the above embodiment, the superheat degree SH1 is calculated based on the temperature and pressure of the refrigerant flowing into the compressor 1, but the present invention is not limited to this. It is also possible to provide temperature sensors at the inlet and outlet of the indoor heat exchanger 4 and calculate the superheat degree SH1 based on the temperatures detected by these temperature sensors. Even in this case, the same effect as the effect described in each of the above-described embodiments can be obtained.

In the above-described third embodiment, an example in which it is mounted on a railway vehicle has been described, but the present invention is not limited to this, and may be installed in a house, a building, a warehouse, an automobile, or the like. Even in these cases, the same effect as the effect described in the third embodiment can be obtained.

In the limiting process of each of the above-described embodiments, the predetermined opening degree θa predetermined to the opening degree of the electronic control valve 2 set based on the superheat degree SH1 is subtracted and corrected. The invention is not limited to this, and the opening degree of the electronic expansion valve 2 may be smaller than the opening degree set based on the superheat degree SH1. For example, it may be set to the minimum opening that the electronic expansion valve 2 can take, or the predetermined opening θa may be set to be larger as the refrigerant pressure Pm at the start of the restriction process is larger. Alternatively, the refrigerant pressure Pm may be monitored while the restriction process is being executed, and the predetermined opening degree θa may be adjusted based on the monitoring result.

Although the restriction process of each of the above-described embodiments is configured to be terminated after continuing for a predetermined period T1 set in advance, the execution period of the restriction process of the present invention is not limited to the predetermined period T1 and may be appropriately changed. Can be changed. For example, the predetermined period T1 may be set to be longer as the refrigerant pressure Pm at the start of the restriction process is higher. Alternatively, the restriction process may be terminated when the refrigerant pressure Pm has dropped to the predetermined refrigerant pressure P2. The refrigerant pressure P2 is preferably the refrigerant pressure when the amount of refrigerant corresponding to the upper limit of the heat exchange capacity of the indoor heat exchanger 4 passes through the low-pressure refrigerant pipe 25.

In the acceleration process of each of the above-described embodiments, the predetermined opening degree θb that is set in advance is added to the opening degree of the electronic control valve 2 that is set based on the superheat degree SH1. The opening degree of the electronic expansion valve 2 is not limited to this, and may be set to be larger than the opening degree set based on the superheat degree SH1. For example, the maximum opening that can be taken by the electronic expansion valve 2 may be set, or the predetermined opening θb may be set smaller as the refrigerant pressure Pm at the start of the acceleration process is smaller. Alternatively, the refrigerant pressure Pm may be monitored while the acceleration process is being executed, and the predetermined opening degree θb may be adjusted based on the monitoring result.

The promotion process of each of the above embodiments is configured to be terminated after continuing for a predetermined period T2 set in advance, but the implementation period of the promotion process in the present invention is not limited to the predetermined period T2, and may be appropriately changed. Can be changed. For example, the predetermined period T2 may be set to be longer as the refrigerant pressure Pm at the start of the acceleration process is smaller. Alternatively, or if the refrigerant pressure Pm rises to a predetermined refrigerant pressure P3, the limiting process may be ended.

1 compressor, 2 electronic expansion valve, 3 outdoor heat exchanger, 4 indoor heat exchanger, 7 control device, 8 high pressure control valve, 9 low pressure control valve, 10 air conditioner, 11 refrigerant temperature sensor, 12 refrigerant pressure sensor , 14 room temperature sensor, 15 remote control, 20 refrigerant line, 21 high pressure control refrigerant passage, 22 low pressure control refrigerant passage, 23 control pressure introducing pipe, 25 low pressure refrigerant pipe, 26 high pressure refrigerant pipe, 27 hot gas bypass pipe, 28 Accumulator, 29 four-way valve, 32 solenoid valve, 50 closed container, 51 fixed scroll, 52 rocking scroll, 53 discharge passage, 54 fixed spiral body, 55 swinging spiral body, 60 volume control mechanism, 61 back pressure passage, 62 back pressure chamber , 63 coil springs, 64 bypass valves, 65 bypass passages.

Claims (11)

An air conditioner having a refrigerant circuit in which a compressor, an outdoor heat exchanger, an indoor heat exchanger and an electronic expansion valve are connected by a refrigerant pipe,
An intermediate compression chamber in which a refrigerant in the middle of compression of the compressor is present, and a bypass passage communicating with a low pressure space in which a refrigerant having a lower pressure than the refrigerant in the intermediate compression chamber is present,
A bypass valve for opening and closing the bypass passage,
A control device for performing superheat control for setting the opening degree of the electronic expansion valve based on the superheat of the refrigerant,
The control device opens the opening of the electronic expansion valve to a predetermined opening with respect to the opening set by the superheat control based on the switching of the bypass valve from the closed state to the open state. restriction processing start the corrected to a value smaller by degrees,
The air conditioner , wherein the control unit sets the predetermined opening degree based on a detection result of a pressure detection unit that detects the pressure of the refrigerant flowing into the compressor . The air conditioner according to claim 1, wherein
The predetermined opening degree is set to be larger as the pressure of the refrigerant at the start of the limiting process is higher.
An air conditioner characterized by the above. The air conditioner according to claim 1, wherein
While performing the limiting process, the pressure of the refrigerant is monitored, and the predetermined opening is adjusted based on the monitoring result.
An air conditioner characterized by the above. An air conditioner having a refrigerant circuit in which a compressor, an outdoor heat exchanger, an indoor heat exchanger and an electronic expansion valve are connected by a refrigerant pipe,
An intermediate compression chamber in which a refrigerant in the middle of compression of the compressor is present, and a bypass passage communicating with a low pressure space in which a refrigerant having a lower pressure than the refrigerant in the intermediate compression chamber is present,
A bypass valve for opening and closing the bypass passage,
A control device for performing superheat control for setting the opening degree of the electronic expansion valve based on the superheat of the refrigerant,
The control device corrects the opening degree of the electronic expansion valve to a value smaller than a value set by the superheat control based on the switching of the bypass valve from the closed state to the open state. the restriction process to begin,
The air conditioner is characterized in that the control device sets the detection condition of the pressure detection means for detecting the pressure of the refrigerant flowing into the compressor to be equal to or higher than a first predetermined pressure as a start condition of the restriction process . An air conditioner having a refrigerant circuit in which a compressor, an outdoor heat exchanger, an indoor heat exchanger and an electronic expansion valve are connected by a refrigerant pipe,
An intermediate compression chamber in which a refrigerant in the middle of compression of the compressor exists, and a bypass passage communicating with a low-pressure space in which a refrigerant having a lower pressure than the refrigerant in the intermediate compression chamber exists,
A bypass valve for opening and closing the bypass passage,
A control device for performing superheat control for setting the opening degree of the electronic expansion valve based on the superheat of the refrigerant,
Wherein the controller detects a change request to switch to the closed state the bypass valve from the open state, the predetermined opening degree with respect to the opening set an opening degree of the electronic expansion valve by the superheat control start the promotion processing for correcting to a large value only, then conversion example off the bypass valve from the open state to the closed state,
The air conditioner , wherein the control unit sets the predetermined opening degree based on a detection result of a pressure detection unit that detects the pressure of the refrigerant flowing into the compressor . The air conditioner according to claim 5,
The predetermined opening degree is set smaller as the pressure of the refrigerant at the start of the promotion processing is smaller.
An air conditioner characterized by the above. The air conditioner according to claim 5,
While executing the acceleration process, the pressure of the refrigerant is monitored, and the predetermined opening is adjusted based on the monitoring result.
An air conditioner characterized by the above. The air conditioner according to any one of claims 1 to 9 ,
Wherein the compressor startup, setting the opening degree of the electronic expansion valve during startup opening, the air conditioning apparatus characterized by setting the bypass valve to the open valve state. An air conditioner for a railway vehicle, comprising the air conditioner according to any one of claims 1 to 8 mounted on a vehicle,
The air conditioner for a railway vehicle, wherein the compressor is arranged so as to be inclined with respect to a horizontal plane. A refrigerant circuit in which a compressor, an outdoor heat exchanger, an indoor heat exchanger and an electronic expansion valve are connected by a refrigerant pipe line,
An intermediate compression chamber in which a refrigerant in the middle of compression of the compressor is present, and a bypass passage communicating with a low pressure space in which a refrigerant having a lower pressure than the refrigerant in the intermediate compression chamber is present,
A bypass valve for opening and closing the bypass passage,
A method for controlling an air conditioner comprising:
A superheat control step of setting the opening degree of the electronic expansion valve based on the superheat of the refrigerant,
Based on the bypass valve being switched from the closed state to the open state, the opening degree of the electronic expansion valve is a value smaller than the opening degree set in the superheat degree control step by a predetermined opening degree. And the limiting process to correct
Bei to give a,
The said opening degree is set based on the pressure of the refrigerant which flows into the said compressor , The control method of the air conditioning apparatus characterized by the above-mentioned . A refrigerant circuit in which a compressor, an outdoor heat exchanger, an indoor heat exchanger and an electronic expansion valve are connected by a refrigerant pipe line,
An intermediate compression chamber in which a refrigerant in the middle of compression of the compressor exists, and a bypass passage communicating with a low-pressure space in which a refrigerant having a lower pressure than the refrigerant in the intermediate compression chamber exists,
A bypass valve for opening and closing the bypass passage,
A method for controlling an air conditioner comprising:
A superheat control step of setting the opening degree of the electronic expansion valve based on the superheat of the refrigerant,
Upon detecting a change request to switch to the closed state the bypass valve from the open state, to a value larger by a predetermined angle with respect to the opening set an opening degree of the electronic expansion valve in the superheat degree control process A facilitating process to correct,
Bei to give a,
The said opening degree is set based on the pressure of the refrigerant which flows into the said compressor , The control method of the air conditioning apparatus characterized by the above-mentioned .

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