JP7331214B1 - Air conditioner and air conditioner control method - Google Patents

Abstract

A compressor power reduction and a compressor torque increase are suppressed.
A circulating flow path that guides the refrigerant that has passed through the heating section 20 to the accumulator 30, a bypass flow path that guides the refrigerant to the accumulator 30 without passing through the heating section 20, and a throttle valve 40 that is arranged in the circulating flow path. and a control unit 90 that controls the opening degree of the throttle valve 50 arranged in the bypass flow path. When the proportion of gaseous refrigerant in the inflowing refrigerant is greater than the proportion of gaseous refrigerant in the outflowing refrigerant flowing out of the accumulator 30 and the pressure of the refrigerant sucked by the compressor 10 is higher than a predetermined pressure, the inflowing refrigerant A vehicle air conditioner 100 is provided that controls the opening degrees of a throttle valve 40 and a throttle valve 50 so that the proportion of liquid refrigerant is greater than the proportion of liquid refrigerant in an outflowing refrigerant.
[Selection drawing] Fig. 3

Description

The present disclosure relates to an air conditioner and a control method for the air conditioner.

Conventionally, in a heat pump type vehicle air conditioner, in order to prevent frost on the outdoor heat exchanger, the high temperature and high pressure gas discharged from the compressor is passed through the indoor heat exchanger without going through the outdoor heat exchanger. It is known to implement an anti-frost operation that circulates between an accumulator and a compressor (see for example US Pat. In Patent Document 1, when the pressure on the downstream side of the outdoor heat exchanger becomes lower than a predetermined value, it is determined that the heat exchange capacity of the outdoor heat exchanger has decreased due to the adhesion of frost, and the outdoor heat exchanger It is disclosed that the heat pump is operated in a refrigerant circuit that does not use

JP-A-2000-343934

However, when the heat pump is operated in a refrigerant circuit that does not use an outdoor heat exchanger, the lower the pressure of the refrigerant flowing into the compressor from the accumulator, the lower the suction density of the refrigerant and the less power the compressor has. will decline. Also, the higher the pressure of the refrigerant flowing into the compressor from the accumulator, the higher the suction density of the refrigerant, and the higher the torque required to operate the compressor at the desired rotational speed.

The present disclosure has been made in view of such circumstances, and the torque of the compressor due to the decrease in the power of the compressor due to the decrease in the pressure of the refrigerant flowing into the compressor and the increase in the pressure of the refrigerant flowing into the compressor. An object of the present invention is to provide an air conditioner and a control method for the air conditioner that can suppress the increase.

In order to solve the above problems, the present disclosure employs the following means.
An air conditioner according to the present disclosure includes a compressor that compresses a refrigerant, a heating unit that heats an object to be heated with the refrigerant discharged from the compressor, and a liquid component in the refrigerant sucked by the compressor. an accumulator, a circulation passage that guides the refrigerant that has passed through the heating unit to the accumulator, a bypass passage that guides the refrigerant discharged from the compressor without passing through the heating unit to the accumulator, and the a first throttle mechanism arranged in a circulation flow path for decompressing the refrigerant flowing out of the heating unit; a second throttle mechanism arranged in the bypass flow path for decompressing the refrigerant discharged from the compressor; A detection unit that detects the pressure of the refrigerant sucked by the compressor, and a control unit that controls a first opening degree of the first throttle mechanism and a second opening degree of the second throttle mechanism, wherein the control When the pressure of the refrigerant detected by the detection unit is lower than a predetermined pressure, the refrigerant depressurized by the first throttle mechanism and the refrigerant depressurized by the second throttle mechanism flow into the accumulator containing the refrigerant. The first opening degree and the second opening degree are controlled so that the proportion of gas refrigerant in the inflowing refrigerant is greater than the proportion of gas refrigerant in the outflowing refrigerant flowing out of the accumulator, and the detection unit detects When the pressure of the refrigerant to be applied is higher than the predetermined pressure, the first opening and controlling the second degree of opening;

In the air conditioner control method according to the present disclosure, the air conditioner includes a compressor that compresses a refrigerant, a heating unit that heats an object to be heated with the refrigerant discharged from the compressor, and a suction an accumulator for separating the liquid in the refrigerant, a circulation passage for guiding the refrigerant that has passed through the heating section to the accumulator, and the refrigerant discharged from the compressor without passing through the heating section; a bypass flow path leading to an accumulator; a first throttle mechanism disposed in the circulation flow path for decompressing the refrigerant flowing out of the heating unit; and a refrigerant discharged from the compressor disposed in the bypass flow path. and a second throttling mechanism that decompresses the pressure of the refrigerant sucked by the compressor, the first The proportion of gaseous refrigerant in the refrigerant flowing into the accumulator containing the refrigerant decompressed by the throttle mechanism and the refrigerant decompressed by the second throttle mechanism is the proportion of the gaseous refrigerant in the outflowing refrigerant flowing out of the accumulator. a first control step of controlling the first opening degree of the first throttle mechanism and the second opening degree of the second throttle mechanism so that the pressure of the refrigerant detected by the detection step is greater than the predetermined pressure , the ratio of the liquid refrigerant in the inflowing refrigerant is higher than the ratio of the liquid refrigerant in the outflowing refrigerant flowing out of the accumulator, controlling the first opening and the second opening 2 control steps.

According to the present disclosure, an air conditioner capable of suppressing a decrease in power of the compressor due to a decrease in pressure of refrigerant flowing into the compressor and an increase in torque of the compressor due to an increase in pressure of refrigerant flowing into the compressor; A control method for an air conditioner can be provided.

1 is a refrigerant circuit diagram of a vehicle air conditioner according to an embodiment of the present disclosure; FIG. FIG. 2 is a refrigerant circuit diagram showing a refrigerant flow during heat pump heating operation of the vehicle air conditioner. FIG. 3 is a refrigerant circuit diagram showing refrigerant flow during hot gas heating operation of the vehicle air conditioner. 4 is a flowchart showing the operation of the vehicle air conditioner during hot gas heating operation. 4 is a flowchart showing the operation of the vehicle air conditioner during hot gas heating operation. FIG. 4 is a Mollier diagram showing the state of refrigerant during hot gas heating operation. FIG. 3 is a refrigerant circuit diagram showing refrigerant flow during dehumidifying and heating operation of the vehicle air conditioner. FIG. 3 is a refrigerant circuit diagram showing refrigerant flow during cooling operation of the vehicle air conditioner.

A heat pump vehicle air conditioner (air conditioner) 100 according to an embodiment of the present disclosure will be described below with reference to FIG. 1 . As shown in FIG. 1, a vehicle air conditioner 100 of the present embodiment includes a compressor 10, a heating unit 20, an accumulator 30, a throttle valve (first throttle mechanism) 40, a throttle valve (second throttle mechanism) ) 50, an on-off valve (switching portion) 61, an on-off valve (switching portion) 62, an on-off valve 63, an on-off valve (first on-off valve) 64, an on-off valve (second on-off valve) 65, and a throttle. Valve (third throttle mechanism) 70, outdoor heat exchanger 80, outdoor fan 81, vehicle interior heat exchanger (evaporator) 85, indoor blower 86, controller 90, refrigerant heater 91, pressure A sensor 92 , a temperature sensor 93 , a temperature sensor 94 , a temperature sensor 95 and a pressure sensor 96 are provided.

The vehicle air conditioner 100 of the present embodiment is a device that generates warm air with a heating unit 20 installed inside the vehicle, or generates cool air with an in-vehicle heat exchanger 85 installed inside the vehicle, and blows the air into the vehicle. . The vehicle air conditioner 100 operates the outdoor heat exchanger 80 as an evaporator during the heat pump heating operation, and operates the outdoor heat exchanger 80 as a condenser during the cooling operation. Further, the vehicle air conditioner 100 performs heating only by the power of the compressor 10 without passing the refrigerant through the outdoor heat exchanger 80 when the outside air temperature is below a predetermined temperature (for example, −20° C.). Gas heating operation is possible. The refrigerant used in the vehicle air conditioner 100 of this embodiment is, for example, HFO-1234yf.

The compressor 10 is a device that compresses refrigerant flowing from the accumulator 30 . The compressor 10 is, for example, an electric power compressor that drives a motor (not shown) to compress refrigerant. The compressor 10 compresses the refrigerant flowing from the refrigerant pipe L1 and discharges it to the refrigerant pipe L2. The refrigerant discharged to the refrigerant pipe L2 is guided to the heating unit 20 via the refrigerant pipe L3 and the refrigerant pipe L4.

The heating unit 20 is a device that heats air (an object to be heated) blown by the indoor blower 86 with high-temperature, high-pressure refrigerant discharged from the compressor 10 . The air heated by the heating unit 20 is blown into the vehicle interior. The refrigerant that has exchanged heat with the air in the heating unit 20 is guided to the throttle valve 40 arranged in the refrigerant pipe L5.

The accumulator 30 is a device that separates at least part of the liquid in the refrigerant sucked by the compressor 10 . The accumulator 30 guides the gas-phase or gas-liquid two-phase refrigerant to the compressor 10 via the refrigerant pipe L1.

The throttle valve 40 is a mechanism that is arranged in the refrigerant pipe L<b>5 and decompresses the refrigerant that has flowed out from the heating unit 20 . The opening degree of the throttle valve 40 is controlled by the controller 90 . The refrigerant decompressed by the throttle valve 40 flows through the refrigerant pipe L5.

The throttle valve 50 is arranged in the refrigerant pipe L6 connected to the refrigerant pipe L3 and is a mechanism for reducing the pressure of the refrigerant discharged from the compressor 10 . The opening degree of the throttle valve 50 is controlled by the controller 90 . The refrigerant decompressed by the throttle valve 50 is guided from the refrigerant pipe L6 to the accumulator 30 via the refrigerant pipe L7. Refrigerant pipe L7 is a pipe that connects in-vehicle heat exchanger 85 and accumulator 30 .

The on-off valve 61 is arranged in the refrigerant pipe L8 and is a device that switches between an open state in which the refrigerant flows through the refrigerant pipe L8 and a closed state in which the refrigerant does not flow through the refrigerant pipe L8. The refrigerant pipe L8 is a pipe that connects the refrigerant pipe L5 and the refrigerant pipe L9. The refrigerant pipe L9 is a pipe that connects the refrigerant pipe L10 and the refrigerant pipe L7. The refrigerant pipe L10 is a pipe that connects the outdoor heat exchanger 80 and the vehicle interior heat exchanger 85 .

The on-off valve 62 is arranged in the refrigerant pipe L6 and is a device that switches between an open state in which the refrigerant flows through the refrigerant pipe L6 and a closed state in which the refrigerant does not flow through the refrigerant pipe L6.
The on-off valve 63 is arranged in the refrigerant pipe L11 and is a device that switches between an open state in which the refrigerant flows through the refrigerant pipe L11 and a closed state in which the refrigerant does not flow through the refrigerant pipe L11.

The on-off valve 64 is arranged in the refrigerant pipe L5, and is in an open state in which the refrigerant flows toward the outdoor heat exchanger 80 from the connecting portion of the refrigerant pipe L5 with the refrigerant pipe L8, and the connection between the refrigerant pipe L5 and the refrigerant pipe L8. It is a device for switching between a closed state and a closed state in which the refrigerant is not allowed to flow toward the outdoor heat exchanger 80 rather than the portion.
The on-off valve 65 is arranged in the refrigerant pipe L9, and is a device that switches between an open state in which the refrigerant flows through the refrigerant pipe L9 and a closed state in which the refrigerant does not flow through the refrigerant pipe L9.

The throttle valve 70 is a mechanism that is arranged in the refrigerant pipe L<b>10 and reduces the pressure of the refrigerant guided from the outdoor heat exchanger 80 . The opening degree of the throttle valve 70 is controlled by the controller 90 . The refrigerant decompressed by the throttle valve 70 is guided to the in-vehicle heat exchanger 85 through the refrigerant pipe L10.

The outdoor heat exchanger 80 is a device that is installed outside the vehicle and exchanges heat between the outside air and the refrigerant. The outdoor heat exchanger 80 operates as an evaporator during the heat pump heating operation, and evaporates the refrigerant to cool the outside air. Also, the outdoor heat exchanger 80 operates as a condenser during cooling operation, condenses the refrigerant, and heats the outside air. The outdoor fan 81 is a device that blows outside air to the outdoor heat exchanger 80 to promote heat exchange between the outside air and the refrigerant.

The in-vehicle heat exchanger (evaporator) 85 is a device that cools or dehumidifies the air by evaporating the refrigerant that has passed through the outdoor heat exchanger 80 and has been decompressed by the throttle valve 70 . The indoor blower 86 blows air toward the in-vehicle heat exchanger 85 to guide the air cooled or dehumidified in the in-vehicle heat exchanger 85 into the vehicle interior via the heating unit 20 .

The controller 90 is a device that controls each part of the vehicle air conditioner 100 . The control unit 90 reads and executes a control program stored in a storage unit (not shown), thereby executing various processes for controlling each unit of the vehicle air conditioner 100 .

The refrigerant heater 91 is a device that is arranged downstream of the on-off valve 61 in the refrigerant pipe L8 and heats the refrigerant that flows into the accumulator 30 . For example, when the hot gas heating operation is started, the control unit 90 operates the refrigerant heater 91 to heat the refrigerant in order to increase the pressure of the refrigerant sucked by the compressor 10 .

The pressure sensor 92 is a sensor that detects the pressure of the refrigerant flowing through the refrigerant pipe L1. The temperature sensor 93 is a sensor that detects the temperature of the refrigerant flowing through the refrigerant pipe L1. The temperature sensor 94 is a sensor that detects the temperature of the refrigerant flowing through the refrigerant pipe L2. The temperature sensor 95 is a sensor that detects the temperature of the refrigerant flowing through the refrigerant pipe L5 between the heating section 20 and the throttle valve 40. As shown in FIG. The pressure sensor 96 is a sensor that detects the pressure of the refrigerant flowing through the refrigerant pipe L5 between the heating section 20 and the throttle valve 40. As shown in FIG.

In this embodiment, both the pressure sensor 92 and the temperature sensor 93 are provided in the refrigerant pipe L1, but other aspects may be adopted. For example, only the temperature sensor 93 may be provided in the refrigerant pipe L1, and the pressure of the refrigerant flowing through the refrigerant pipe L1 may be detected (estimated) from the temperature detected by the temperature sensor 93.

<Heat pump heating operation>
The operation of the vehicle air conditioner 100 according to the present embodiment during the heat pump heating operation will be described with reference to FIG. FIG. 2 is a refrigerant circuit diagram showing the refrigerant flow during the heat pump heating operation of the vehicle air conditioner 100. As shown in FIG. The heat pump heating operation is performed, for example, when the temperature outside the vehicle where the outdoor heat exchanger 80 is installed is not below a predetermined temperature (eg, -20°C).

Arrows shown in FIG. 2 indicate the flow direction of the refrigerant. As shown in FIG. 2, the refrigerant circulates through the compressor 10, the heating section 20, the throttle valve 40, the outdoor heat exchanger 80, the accumulator 30, and the compressor 10 in this order during the heat pump heating operation. Refrigerant pipes L1, L2, L3, L4, L5, L9, and L7 form a circulation flow path for circulating the refrigerant.

During the heat pump heating operation, the outdoor heat exchanger 80 operates as an evaporator and evaporates the refrigerant to cool the outside air. During the heat pump heating operation, the controller 90 opens the on-off valves 64 and 65 and closes the on-off valves 61 , 62 and 63 .

<Hot gas heating operation>
The operation of the vehicle air conditioner 100 according to the present embodiment during the hot gas heating operation will be described with reference to FIG. FIG. 3 is a refrigerant circuit diagram showing refrigerant flow during hot gas heating operation of the vehicle air conditioner 100 . Arrows shown in FIG. 3 indicate the flow direction of the refrigerant. The hot gas heating operation is performed, for example, when the temperature outside the vehicle where the outdoor heat exchanger 80 is installed is below a predetermined temperature (eg, -20°C).

As shown in FIG. 3, part of the refrigerant circulates through the compressor 10, the heating section 20, the throttle valve 40, the accumulator 30, and the compressor 10 in this order during the hot gas heating operation. Refrigerant pipes L1, L2, L3, L4, L5, L8, L9, and L7 form a circulation flow path for circulating the refrigerant. Refrigerant pipes L<b>5 , L<b>8 , L<b>9 and L<b>7 guide the refrigerant that has passed through heating unit 20 to accumulator 30 .

Another part of the refrigerant is guided from the refrigerant pipe L3 to the refrigerant pipe L7 via the refrigerant pipe L6 without flowing through the refrigerant pipes L4, L5, L8, and L9. The refrigerant pipe L<b>6 is a bypass flow path that guides the refrigerant discharged from the compressor 10 to the accumulator 30 without passing through the heating section 20 .

When hot gas heating operation is performed, the control unit 90 closes the on-off valve 64 and the on-off valve 65, and the refrigerant is supplied to the circulation flow path formed by the refrigerant pipes L1, L2, L3, L4, L5, L8, L9, and L7. circulate. In the vehicle air conditioner 100 of the present embodiment, the amount of refrigerant enclosed in the refrigerant pipes consisting of the refrigerant pipes L1 to L11 is determined by the heating unit 20 when the on-off valve 64 and the on-off valve 65 are closed. It is set up to allow air heating.

Here, the operation of the vehicle air conditioner 100 during the hot gas heating operation will be described with reference to FIGS. 4 to 6. FIG. 4 and 5 are flowcharts showing the operation of the vehicle air conditioner 100 during the hot gas heating operation. Each step shown in FIGS. 4 and 5 is executed by the control unit 90 . FIG. 6 is a Mollier diagram showing the state of the refrigerant during the hot gas heating operation.

In step S101, the controller 90 controls the on-off valves 61, 63, 64, 65 to be closed.
In step S102, the control unit 90 determines whether or not the refrigerant pressure LP detected by the pressure sensor 92 exceeds the threshold pressure. If YES, the process proceeds to step S108, and if NO, the process proceeds to step S103. proceed.

In step S103, the controller 90 controls the on-off valve 62 to open. By opening the on-off valve 62 and operating the compressor 10, the control unit 90 circulates the entire amount of the refrigerant discharged from the compressor 10 so as to be guided to the accumulator 30 via the refrigerant pipe L6. Thus, the control unit 90 sets the vehicle air conditioner 100 to the first operation mode in which the refrigerant discharged from the compressor 10 is not guided to the heating unit 20 but is guided to the refrigerant pipe L6.

In step S<b>104 , the control unit 90 controls the opening degree of the throttle valve 50 to be adjusted. Step S104 is executed when NO is determined in step S102, when the pressure LP of the refrigerant detected by the pressure sensor 92 is equal to or lower than the threshold pressure and the hot gas heating operation using the heating unit 20 cannot be performed. be.

Therefore, in step S104, in order to enable the hot gas heating operation using the heating unit 20, the opening degree of the throttle valve 50 is adjusted, and the amount of refrigerant circulating through the refrigerant pipe L6 to the accumulator 30 is adjusted. to adjust. The controller 90 controls the opening of the throttle valve 50 such that the larger the difference between the refrigerant pressure LP detected by the pressure sensor 92 and the threshold pressure, the larger the opening of the throttle valve 50 . By doing so, it is possible to shorten the start-up time required to make the hot gas heating operation using the heating unit 20 executable.

In step S105, the control unit 90 determines whether or not the refrigerant pressure LP detected by the pressure sensor 92 exceeds the threshold pressure. If YES, the process proceeds to step S106. The adjustment of the degree of opening of the valve 50 is performed again.

In step S106, the control unit 90 adjusts the opening degree of the throttle valve 40 prior to opening the on-off valve 61 in step S107. The opening degree of the throttle valve 40 is adjusted so as to suppress a decrease in the pressure of the refrigerant circulating in the refrigeration cycle when the on-off valve 61 is opened.

In step S107, the controller 90 controls the on-off valve 61 to open. By opening the on-off valve 61, part of the refrigerant discharged from the compressor 10 circulates through the compressor 10, the heating section 20, the throttle valve 40, the accumulator 30, and the compressor 10 in this order.

In this way, the control unit 90 sets the vehicle air conditioner 100 to the first operation mode in which the refrigerant discharged from the compressor 10 is not guided to the heating unit 20 but is guided to the refrigerant pipe L6. Switching to the second operation mode in which the refrigerant is led to both the heating unit 20 and the refrigerant pipe L6. The on-off valve 61 functions as a switching unit that switches between the first operation mode and the second operation mode. The control unit 90 controls the on-off valve 61 to switch the first operation mode to the second operation mode when the pressure of the refrigerant sucked by the compressor 10 exceeds the threshold pressure.

In step S108, the controller 90 controls the on-off valve 62 to open. In step S109, the controller 90 controls the on-off valve 61 to open. Control unit 90 opens on-off valve 62 and on-off valve 61 and operates compressor 10 , whereby part of the refrigerant discharged from compressor 10 is guided to heating unit 20 and discharged from compressor 10 . Another part of the refrigerant is guided to the accumulator 30 from the refrigerant pipe L6 without passing through the heating unit 20.

In step S110, the control unit 90 adjusts the opening degree of the throttle valve 40 so that the refrigerant that has passed through the heating unit 20 becomes a liquid refrigerant when performing the hot gas heating operation in which the refrigerant is introduced to the heating unit 20. The control unit 90 adjusts the opening degree of the throttle valve 40 so that the degree of subcooling SC, which is the difference between the refrigerant temperature at point b and the refrigerant temperature at point b' shown in FIG. 6, becomes a predetermined value. The controller 90 calculates the supercooling degree SC from the temperature detected by the temperature sensor 95 and the pressure detected by the pressure sensor 96 .

At step S111, the controller 90 calculates the specific enthalpies ha, hb, and hc of the points a, b, and c shown in FIG. 6, respectively. The specific enthalpy ha of the point a is calculated from the temperature detected by the temperature sensor 94 and the pressure detected by the pressure sensor 96 . The specific enthalpy hb of the point b is calculated from the temperature detected by the temperature sensor 95 and the pressure detected by the pressure sensor 96 . The specific enthalpy hc at the point c is calculated from either the temperature detected by the temperature sensor 93 or the pressure detected by the pressure sensor 92 and the rotation speed of the motor that drives the compressor 10 .

In step S112, the controller 90 calculates the refrigerant circulation amount Gr1 in the refrigerant pipe L6. The refrigerant circulation amount Gr<b>1 is calculated from the opening degree of the throttle valve 50 , the pressure HP at point a, the pressure LP at point c, and the temperature detected by the temperature sensor 93 .

In step S113, the controller 90 calculates the refrigerant circulation amount Gr2 in the refrigerant pipe L5. The refrigerant circulation amount Gr2 is calculated from the opening degree of the throttle valve 40, the pressure HP at the point b, the pressure LP at the point c, and the temperature detected by the temperature sensor 93.

In step S114, the control unit 90 determines whether or not the refrigerant pressure LP detected by the pressure sensor 92 exceeds a predetermined pressure. If YES, the process proceeds to step S115, and if NO, the process proceeds to step S116. proceed. The predetermined pressure is higher than the aforementioned threshold pressure and predetermined as a pressure suitable for the hot gas heating operation.

At step S115, the controller 90 increases the opening of the throttle valve 50 so that (ha-hc)×Gr1>(hc-hb)×Gr2. By doing so, the ratio of the gaseous refrigerant in the inflowing refrigerant flowing into the accumulator 30 containing the refrigerant decompressed by the throttle valve 40 and the refrigerant decompressed by the throttle valve 50 is reduced to the outflowing refrigerant outflowing from the accumulator 30. It can be higher than the proportion of gas refrigerant.

In FIG. 6, by increasing the opening of the throttle valve 50, the point c corresponding to the outlet side of the accumulator 30 (the suction side of the compressor 10) can be brought closer to the point e than to the point d. Point d corresponds to the downstream side of throttle valve 40 and point e corresponds to the downstream side of throttle valve 50 .

By making the ratio of the gas refrigerant in the refrigerant flowing into the accumulator 30 higher than the ratio of the gas refrigerant in the refrigerant flowing out of the accumulator 30, the amount of liquid refrigerant stored in the accumulator 30 is reduced. As a result, the pressure of the refrigerant flowing into the compressor 10 increases as the amount of refrigerant flowing through the refrigerating cycle increases, and a decrease in the power of the compressor 10 can be suppressed.

In step S116, the controller 90 reduces the opening of the throttle valve 50 so that (ha-hc)×Gr1<(hc-hb)×Gr2. By doing so, the ratio of the liquid refrigerant in the inflowing refrigerant flowing into the accumulator 30 containing the refrigerant decompressed by the throttle valve 40 and the refrigerant decompressed by the throttle valve 50 is reduced to that in the outflowing refrigerant flowing out of the accumulator 30. It can be higher than the proportion of liquid refrigerant. In FIG. 6, by decreasing the opening degree of the throttle valve 50, the point c corresponding to the outlet side of the accumulator 30 (the suction side of the compressor 10) can be brought closer to the point d than to the point e.

By making the ratio of the liquid refrigerant in the inflow refrigerant that flows into the accumulator 30 higher than the ratio of the liquid refrigerant in the outflow refrigerant that flows out from the accumulator 30, the liquid refrigerant stored in the accumulator 30 increases and the accumulator The proportion of liquid refrigerant contained in the refrigerant flowing out from 30 is reduced. As a result, the pressure of the refrigerant flowing into the compressor 10 decreases as the amount of refrigerant flowing through the refrigerating cycle decreases, and an increase in the torque of the compressor 10 can be suppressed.

In step S117, the control unit 90 determines whether or not an instruction to end the hot gas heating operation has been input, and if YES, ends the processing of this flowchart. If NO, the process after step S110 is executed again.

In the hot gas heating operation described above, when the power of the compressor 10 is reduced, the controller 90 controls the opening of the throttle valve 40 ( first degree of opening) and the degree of opening of the throttle valve 50 (second degree of opening). Further, when increasing the power of the compressor 10, the control unit 90 controls the opening degree (first opening degree) of the throttle valve 40 and 50 opening (second opening) is controlled.

<Dehumidification and heating operation>
The operation of the vehicle air conditioner 100 according to the present embodiment during the dehumidifying and heating operation will be described with reference to FIG. 7 . FIG. 7 is a refrigerant circuit diagram showing the refrigerant flow during the dehumidifying and heating operation of the vehicle air conditioner 100. As shown in FIG.

Arrows shown in FIG. 7 indicate the flow direction of the coolant. As shown in FIG. 7, the refrigerant circulates through the compressor 10, the heating section 20, the throttle valve 40, the outdoor heat exchanger 80, the in-vehicle heat exchanger 85, the accumulator 30, and the compressor 10 in this order during the dehumidifying and heating operation. Refrigerant pipes L1, L2, L3, L4, L5, L10, and L7 form a circulation flow path for circulating the refrigerant.

During the dehumidifying and heating operation, the outdoor heat exchanger 80 operates as an evaporator to evaporate the refrigerant and cool the outside air. During the dehumidification and heating operation, the controller 90 opens the on-off valve 64 and closes the on-off valves 61, 62, 63, and 65. FIG. The control unit 90 drives the indoor blower 86 to guide the air dehumidified by the in-vehicle heat exchanger 85 to the heating unit 20, thereby heating the air by the heating unit 20 while dehumidifying the moisture contained in the air. can do.

<Cooling operation>
The operation of the vehicle air conditioner 100 according to the present embodiment during cooling operation will be described with reference to FIG. 8 . FIG. 8 is a refrigerant circuit diagram showing refrigerant flow during cooling operation of the vehicle air conditioner 100 .

Arrows shown in FIG. 8 indicate the flow direction of the coolant. As shown in FIG. 8, during cooling operation, the refrigerant circulates through the compressor 10, the outdoor heat exchanger 80, the vehicle interior heat exchanger 85, the accumulator 30, and the compressor 10 in this order. Refrigerant pipes L1, L2, L11, L5, L10, and L7 form a circulation flow path for circulating the refrigerant.

During cooling operation, the outdoor heat exchanger 80 operates as a condenser to condense the refrigerant and heat the outside air. During the cooling operation, the controller 90 opens the on-off valves 63 and 64 and closes the on-off valves 61, 62 and 65. FIG. The controller 90 can drive the indoor blower 86 to blow the air cooled by the outdoor heat exchanger 80 into the vehicle interior.

The operation and effects of the vehicle air conditioner 100 of the present embodiment described above will be described.
According to the vehicle air conditioner 100 of the present embodiment, part of the high-temperature, high-pressure refrigerant discharged from the compressor 10 is supplied to the heating unit 20, and the heating unit 20 heats air (an object to be heated). The refrigerant that has passed through the heating section 20 is decompressed by the throttle valve 40 and guided to the accumulator 30 by the refrigerant pipes L5, L8, L9, and L7. Further, another part of the high-temperature and high-pressure refrigerant discharged from the compressor 10 is guided to the refrigerant pipe L6 (bypass flow path) and decompressed by the throttle valve 50 . The refrigerant depressurized by the throttle valve 50 joins the refrigerant flowing through the refrigerant pipe L7 and is led to the accumulator 30 .

According to the vehicle air conditioner 100 of the present embodiment, when the pressure of the refrigerant sucked by the compressor 10 is lower than the predetermined pressure, the proportion of gas refrigerant in the inflowing refrigerant flowing into the accumulator 30 flows out of the accumulator 30. The degree of opening of throttle valve 40 and the degree of opening of throttle valve 50 are controlled so as to be greater than the proportion of gas refrigerant in the outflowing refrigerant. Therefore, the amount of liquid refrigerant stored in the accumulator 30 is reduced. As a result, the pressure of the refrigerant flowing into the compressor 10 increases with an increase in the amount of refrigerant flowing through the circulation flow path (refrigerant pipes L5, L8, L9, L7) and the bypass flow path (refrigerant pipe L6). 10 power reduction can be suppressed.

Further, according to the vehicle air conditioner 100 of the present embodiment, when the pressure of the refrigerant sucked by the compressor 10 is higher than the predetermined pressure, the ratio of the liquid refrigerant in the refrigerant flowing into the accumulator 30 is reduced from the accumulator 30 to The degree of opening of the throttle valve 40 and the degree of opening of the throttle valve 50 are controlled so that the ratio of the liquid refrigerant in the outflowing refrigerant is greater than that of the refrigerant. Therefore, the amount of liquid refrigerant stored in the accumulator 30 increases. As a result, the pressure of the refrigerant flowing into the compressor 10 decreases as the amount of refrigerant flowing through the circulation flow path (refrigerant pipes L5, L8, L9, L7) and the bypass flow path (refrigerant pipe L6) decreases. 10 torque increase can be suppressed.

According to the vehicle air conditioner 100 of the present embodiment, in the hot gas heating operation in which air is heated by using the power of the compressor 10, compression is performed until the pressure of the refrigerant sucked by the compressor 10 reaches the threshold pressure. The first operation mode is set in which the refrigerant discharged from the machine 10 is not led to the circulation channel but is led to the bypass channel, so that the pressure of the refrigerant can reach the threshold pressure quickly. Further, when the pressure of the refrigerant sucked by the compressor 10 exceeds the threshold pressure, the second operation mode is set, and the air can be appropriately heated by the heating unit 20 .

According to the vehicle air conditioner 100 of the present embodiment, when the power of the compressor 10 is decreased or increased, the pressure of the refrigerant sucked by the compressor fluctuates in accordance with the decrease in the power of the compressor. can be suppressed.

According to the vehicle air conditioner 100 of the present embodiment, when the on-off valve 64 and the on-off valve 65 are closed and the refrigerant is circulated in the circulation flow path, part of the refrigerant sealed in the refrigerant flow path flows into the refrigerant pipe L5. It stays in another refrigerant flow path different from the circulation flow path including the downstream side of the on-off valve 64 and the refrigerant pipe L9. Further, even if the on-off valve 64 and the on-off valve 65 are closed, part of the refrigerant flowing through the circulation flow path flows into the refrigerant pipe L5 downstream of the on-off valve 64 and into the refrigerant pipe L9, thereby closing the circulation flow path. Circulating refrigerant will decrease.

According to the vehicle air conditioner 100 of the present embodiment, when the on-off valve 64 and the on-off valve 65 are closed and the refrigerant is circulated in the circulation flow path, the air can be heated by the heating unit 20. The amount of refrigerant to be enclosed in the refrigerant flow path including the circulation flow path, the bypass flow path, the first flow path (downstream of the on-off valve 64 of the refrigerant pipe L5), and the second flow path (refrigerant pipe L9) is set. It is Therefore, when the on-off valve 64 and the on-off valve 65 are closed and the refrigerant is circulated in the circulation flow path, the air can be appropriately heated by the heating unit 20 .

According to the vehicle air conditioner 100 of the present embodiment, by heating the refrigerant flowing into the accumulator 30 with the refrigerant heater 91, the specific enthalpy of the refrigerant flowing into the accumulator 30 can be increased.

According to the vehicle air conditioner 100 of the present embodiment, by driving the indoor blower 86 and guiding the air dehumidified by the vehicle interior heat exchanger 85 to the heating unit 20, the moisture contained in the air is dehumidified and the heating unit is heated. Air can be heated and blown at 20 .

According to the vehicle air conditioner 100 of the present embodiment, the opening degree of the throttle valve 40 is adjusted so that the refrigerant that has passed through the heating unit 20 becomes liquid refrigerant. As a result, an increase in refrigerant flow noise can be appropriately prevented.

The air conditioner and the control method of the air conditioner described in each of the embodiments described above are grasped, for example, as follows.
An air conditioner (100) according to a first aspect of the present disclosure includes a compressor (10) that compresses a refrigerant, a heating section (20) that heats an object to be heated with the refrigerant discharged from the compressor, and An accumulator (30) that separates liquid from the refrigerant sucked by the compressor, a circulation flow path (L5, L8, L9, L7) that guides the refrigerant that has passed through the heating unit to the accumulator, and the heating unit A bypass flow path (L6) that guides the refrigerant discharged from the compressor to the accumulator without passing through the (40), a second throttle mechanism (50) arranged in the bypass flow path for decompressing the refrigerant discharged from the compressor, a first opening of the first throttle mechanism and the second throttle mechanism; and a control unit (90) for controlling a second degree of opening of the pressure of the refrigerant sucked by the compressor is lower than a predetermined pressure. The proportion of gaseous refrigerant in the refrigerant flowing into the accumulator containing the refrigerant and the refrigerant decompressed by the second throttle mechanism is higher than the proportion of gaseous refrigerant in the outflowing refrigerant flowing out of the accumulator. By controlling the first degree of opening and the second degree of opening, when the pressure of the refrigerant sucked by the compressor is higher than the predetermined pressure, a proportion of liquid refrigerant in the inflowing refrigerant flows out of the accumulator. The first degree of opening and the second degree of opening are controlled so as to be greater than the ratio of the liquid refrigerant in the outflowing refrigerant.

According to the air conditioner according to the first aspect of the present disclosure, part of the high-temperature, high-pressure refrigerant discharged from the compressor is supplied to the heating unit, and the heating target is heated by the heating unit. The refrigerant that has passed through the heating section is depressurized by the first throttle mechanism and guided to the accumulator through the circulation flow path. Further, another part of the high-temperature and high-pressure refrigerant discharged from the compressor is guided to the bypass channel and decompressed by the second throttle mechanism. The refrigerant depressurized by the second throttle mechanism joins the refrigerant flowing through the circulation flow path and is led to the accumulator.

According to the air conditioner according to the first aspect of the present disclosure, when the pressure of the refrigerant sucked by the compressor is lower than the predetermined pressure, the ratio of the gas refrigerant in the inflow refrigerant flowing into the accumulator is the outflow refrigerant flowing out of the accumulator The first degree of opening and the second degree of opening are controlled so as to be greater than the ratio of the gas refrigerant inside. Therefore, the amount of liquid refrigerant stored in the accumulator is reduced. As a result, the pressure of the refrigerant flowing into the compressor increases as the amount of refrigerant flowing through the circulation flow path and the bypass flow path increases, thereby suppressing a decrease in the power of the compressor.

Further, according to the air conditioner according to the first aspect of the present disclosure, when the pressure of the refrigerant sucked by the compressor is higher than the predetermined pressure, the proportion of the liquid refrigerant in the refrigerant flowing into the accumulator flows out of the accumulator. The first degree of opening and the second degree of opening are controlled so as to be greater than the ratio of the liquid refrigerant in the outflowing refrigerant. Therefore, the amount of liquid refrigerant stored in the accumulator increases. As a result, the pressure of the refrigerant flowing into the compressor decreases as the amount of refrigerant flowing through the circulation flow path and the bypass flow path decreases, and an increase in the torque of the compressor can be suppressed.

An air conditioner according to a second aspect of the present disclosure, in the first aspect, further includes the following configuration. That is, a first operation mode in which the refrigerant discharged from the compressor is not guided to the circulation flow path but to the bypass flow path, and a first operation mode in which the refrigerant discharged from the compressor is directed to the circulation flow path and the bypass flow path. A switching unit (61) for switching between a second operation mode leading to both paths, and a switching unit (61) for switching between the second operation mode and the second operation mode, wherein the control unit switches the first The switching unit is controlled to switch the operation mode to the second operation mode.

According to the air conditioner according to the second aspect of the present disclosure, in the hot gas heating operation in which the power of the compressor is used to heat the object to be heated, until the pressure of the refrigerant sucked by the compressor reaches the threshold pressure, The first operation mode in which the refrigerant discharged from the compressor is not guided to the circulation flow path but is guided to the bypass flow path can be set, and the pressure of the refrigerant can reach the threshold pressure quickly. Further, the second operation mode is set when the pressure of the refrigerant sucked by the compressor exceeds the threshold pressure, and the object to be heated can be appropriately heated by the heating unit.

An air conditioner according to a third aspect of the present disclosure, in the first aspect or the second aspect, further includes the following configuration. That is, when the power of the compressor is reduced, the control unit controls the first opening and the second opening so that the ratio of the liquid refrigerant in the inflowing refrigerant does not change.
According to the air conditioner according to the third aspect of the present disclosure, when the power of the compressor is reduced, fluctuations in the pressure of the refrigerant sucked by the compressor are appropriately suppressed in accordance with the reduction of the power of the compressor. be able to.

An air conditioner according to a fourth aspect of the present disclosure, in the first aspect or the second aspect, further includes the following configuration. That is, when increasing the power of the compressor, the controller controls the first opening and the second opening so that the ratio of the liquid refrigerant in the inflowing refrigerant does not change.
According to the air conditioner according to the fourth aspect of the present disclosure, when increasing the power of the compressor, it is possible to appropriately suppress fluctuations in the pressure of the refrigerant sucked by the compressor according to the increase in the power of the compressor. be able to.

An air conditioner according to a fifth aspect of the present disclosure, in the first aspect or the second aspect, further includes the following configuration. That is, a heat exchanger (80) that exchanges heat between the outside air and the refrigerant, a first flow path (L5) that guides the refrigerant that has passed through the heating unit to the heat exchanger, and the heat exchanger A second flow path (L9) that guides the refrigerant that has passed through the accumulator to the accumulator, a first on-off valve (64) arranged in the first flow path, and a second on-off valve arranged in the second flow path (65), wherein when the first on-off valve and the second on-off valve are closed and the refrigerant is circulated in the circulation flow path, the heating unit can heat the object to be heated. The amount of the refrigerant enclosed in the refrigerant flow path including the circulation flow path, the bypass flow path, the first flow path, and the second flow path is set so that

According to the air conditioner according to the fifth aspect of the present disclosure, when the first on-off valve and the second on-off valve are closed and the refrigerant is circulated in the circulation flow path, part of the refrigerant enclosed in the refrigerant flow path is The coolant stays in other refrigerant channels different from the circulation channel including the first channel and the second channel. Further, even when the first on-off valve and the second on-off valve are closed, part of the refrigerant flowing through the circulation flow path flows into the first flow path and the second flow path, and the refrigerant flowing through the circulation flow path decreases.

According to the air conditioner according to the fifth aspect of the present disclosure, when the first on-off valve and the second on-off valve are closed and the refrigerant is circulated in the circulation flow path, the heating unit can heat the object to be heated. The amount of the refrigerant enclosed in the refrigerant channel including the circulation channel, the bypass channel, the first channel, and the second channel is set so that Therefore, when the first on-off valve and the second on-off valve are closed and the refrigerant is circulated in the circulation flow path, the object to be heated can be appropriately heated by the heating unit.

An air conditioner according to a sixth aspect of the present disclosure, in the first aspect or the second aspect, further includes the following configuration. That is, a refrigerant heater (95) is provided for heating the refrigerant flowing into the accumulator.
According to the air conditioner according to the sixth aspect of the present disclosure, the pressure of the refrigerant flowing into the accumulator can be increased by heating the refrigerant flowing into the accumulator with the heater for heating the refrigerant.

An air conditioner according to a seventh aspect of the present disclosure, in the first aspect or the second aspect, further includes the following configuration. That is, a heat exchanger (80) that exchanges heat between the outside air and the refrigerant, an evaporator (85) that evaporates the refrigerant that has passed through the heat exchanger, and air dehumidified by the evaporator. A blower (86) leading to the heating section, a first flow path (L5) leading the refrigerant that has passed through the heating section to the heat exchanger, and the refrigerant that has passed through the heat exchanger via the evaporator to the accumulator; and a second flow path (L9).
According to the air conditioner according to the seventh aspect of the present disclosure, by driving the blower and guiding the air dehumidified by the evaporator to the heating unit, the air is heated by the heating unit while dehumidifying the moisture contained in the air. can be ventilated.

An air conditioner according to an eighth aspect of the present disclosure, in the first aspect or the second aspect, further includes the following configuration. That is, the control section controls the opening degree of the first throttle mechanism so that the refrigerant that has passed through the heating section becomes a liquid refrigerant.
According to the air conditioner according to the eighth aspect of the present disclosure, the opening degree of the first throttle mechanism is adjusted so that the refrigerant that has passed through the heating unit becomes liquid refrigerant. It is possible to appropriately prevent the inflow of refrigerant and the increase in refrigerant flow noise.

In a method for controlling an air conditioner according to a ninth aspect of the present disclosure, the air conditioner includes a compressor that compresses a refrigerant, a heating unit that heats an object to be heated with the refrigerant discharged from the compressor, and the compressor. an accumulator that separates liquid from the refrigerant sucked by the compressor; a circulation passage that guides the refrigerant that has passed through the heating section to the accumulator; and the refrigerant discharged from the compressor without passing through the heating section. a bypass flow path that guides the refrigerant to the accumulator; a first throttle mechanism that is disposed in the circulation flow path and decompresses the refrigerant that has flowed out of the heating unit; and a second throttling mechanism for decompressing the refrigerant, wherein when the pressure of the refrigerant sucked by the compressor is lower than a predetermined pressure, the refrigerant decompressed by the first throttling mechanism and the second throttling mechanism The ratio of the gaseous refrigerant in the inflowing refrigerant flowing into the accumulator containing the refrigerant depressurized by the first A first control step of controlling the degree of opening and the second degree of opening of the second throttle mechanism; and, when the pressure of the refrigerant sucked by the compressor is higher than the predetermined pressure, the proportion of liquid refrigerant in the inflowing refrigerant. and a second control step of controlling the first degree of opening and the second degree of opening so that the proportion of liquid refrigerant in the outflowing refrigerant from the accumulator is greater than that of the liquid refrigerant.

According to the method for controlling an air conditioner according to the ninth aspect of the present disclosure, part of the high-temperature, high-pressure refrigerant discharged from the compressor is supplied to the heating unit, and the object to be heated is heated by the heating unit. The refrigerant that has passed through the heating section is depressurized by the first throttle mechanism and guided to the accumulator through the circulation flow path. Further, another part of the high-temperature and high-pressure refrigerant discharged from the compressor is guided to the bypass channel and decompressed by the second throttle mechanism. The refrigerant depressurized by the second throttle mechanism joins the refrigerant flowing through the circulation flow path and is led to the accumulator.

According to the method for controlling an air conditioner according to the ninth aspect of the present disclosure, when the pressure of the refrigerant sucked by the compressor is lower than the predetermined pressure, the ratio of the gas refrigerant in the inflow refrigerant flowing into the accumulator is The first degree of opening and the second degree of opening are controlled so as to be greater than the proportion of gas refrigerant in the outflowing refrigerant. Therefore, the amount of liquid refrigerant stored in the accumulator decreases, and the ratio of the liquid refrigerant contained in the refrigerant flowing out of the accumulator increases. As a result, the pressure of the refrigerant flowing into the compressor increases as the amount of refrigerant flowing through the circulation flow path and the bypass flow path increases, thereby suppressing a decrease in the power of the compressor.

Further, according to the method for controlling an air conditioner according to the ninth aspect of the present disclosure, when the pressure of the refrigerant sucked by the compressor is higher than the predetermined pressure, the ratio of the liquid refrigerant in the inflow refrigerant flowing into the accumulator is The first degree of opening and the second degree of opening are controlled so as to be greater than the proportion of the liquid refrigerant in the outflowing refrigerant. Therefore, the amount of liquid refrigerant stored in the accumulator increases, and the ratio of the liquid refrigerant contained in the refrigerant flowing out of the accumulator decreases. As a result, the pressure of the refrigerant flowing into the compressor decreases as the amount of refrigerant flowing through the circulation flow path and the bypass flow path decreases, and an increase in the torque of the compressor can be suppressed.

10 compressor 20 heating unit 30 accumulator 40 throttle valve (first throttle mechanism)
50 throttle valve (second throttle mechanism)
61, 62, 63 on-off valve 64 on-off valve (first on-off valve)
65 on-off valve (second on-off valve)
70 Throttle valve 80 Outdoor heat exchanger 81 Outdoor fan 85 In-vehicle heat exchanger (evaporator)
86 Indoor blower 90 Control unit 91 Refrigerant heaters 92, 96 Pressure sensors 93, 94, 95 Temperature sensor 100 Vehicle air conditioners Gr1, Gr2 Refrigerant circulation amounts L1, L2, L3, L4, L5, L6, L7, L8, L9 , L10, L11 refrigerant piping

Claims (9)

a compressor that compresses a refrigerant;
a heating unit that heats an object to be heated with the refrigerant discharged from the compressor;
an accumulator that separates liquid from the refrigerant sucked by the compressor;
a circulation flow path that guides the refrigerant that has passed through the heating unit to the accumulator;
a bypass flow path that guides the refrigerant discharged from the compressor to the accumulator without passing through the heating unit;
a first throttle mechanism arranged in the circulation flow path and decompressing the refrigerant flowing out from the heating unit;
a second throttle mechanism arranged in the bypass flow path for decompressing the refrigerant discharged from the compressor;
a detection unit that detects the pressure of the refrigerant sucked by the compressor;
a control unit that controls a first degree of opening of the first diaphragm mechanism and a second degree of opening of the second diaphragm mechanism;
The control unit
When the pressure of the refrigerant detected by the detection unit is lower than a predetermined pressure, inflowing refrigerant flowing into the accumulator containing the refrigerant decompressed by the first throttle mechanism and the refrigerant decompressed by the second throttle mechanism controlling the first degree of opening and the second degree of opening so that the ratio of the gas refrigerant in the accumulator is greater than the ratio of the gas refrigerant in the refrigerant flowing out from the accumulator;
When the pressure of the refrigerant detected by the detection unit is higher than the predetermined pressure, the ratio of the liquid refrigerant in the inflowing refrigerant is higher than the ratio of the liquid refrigerant in the outflowing refrigerant flowing out of the accumulator. An air conditioner that controls the first degree of opening and the second degree of opening. a first operation mode in which the refrigerant discharged from the compressor is not guided to the circulation flow path but to the bypass flow path; A switching unit that switches between a second operation mode that leads to both,
The control unit controls the switching unit to switch the first operation mode to the second operation mode in response to a pressure of the refrigerant sucked by the compressor exceeding a threshold pressure. Air conditioner as described. Claim 1 or Claim 2, wherein when the power of the compressor is reduced, the control unit controls the first opening and the second opening so that the ratio of liquid refrigerant in the inflowing refrigerant does not change. The air conditioner described in . Claim 1 or Claim 2, wherein when the power of the compressor is increased, the control unit controls the first degree of opening and the second degree of opening so that the proportion of liquid refrigerant in the inflowing refrigerant does not change. The air conditioner described in . a heat exchanger that exchanges heat between the outside air and the refrigerant;
a first flow path that guides the refrigerant that has passed through the heating unit to the heat exchanger;
a second flow path that guides the refrigerant that has passed through the heat exchanger to the accumulator;
a first on-off valve arranged in the first flow path;
a second on-off valve arranged in the second flow path,
When the first on-off valve and the second on-off valve are closed and the refrigerant is circulated in the circulation flow path, the circulation flow path can be heated by the heating unit. 3. The air conditioner according to claim 1, wherein an amount of the refrigerant enclosed in a refrigerant channel including the bypass channel, the first channel, and the second channel is set. 3. The air conditioner according to claim 1, further comprising a refrigerant heater that heats the refrigerant flowing into the accumulator. a heat exchanger that exchanges heat between the outside air and the refrigerant;
an evaporator that evaporates the refrigerant that has passed through the heat exchanger;
a blower that guides the air dehumidified by the evaporator to the heating unit;
a first flow path that guides the refrigerant that has passed through the heating unit to the heat exchanger;
3. The air conditioner according to claim 1, further comprising a second flow path that guides the refrigerant that has passed through the heat exchanger via the evaporator to the accumulator. The air conditioner according to claim 1 or 2, wherein the control section controls the opening degree of the first throttle mechanism so that the refrigerant that has passed through the heating section becomes a liquid refrigerant. A control method for an air conditioner,
The air conditioner is
a compressor that compresses a refrigerant;
a heating unit that heats an object to be heated with the refrigerant discharged from the compressor;
an accumulator that separates liquid from the refrigerant sucked by the compressor;
a circulation flow path that guides the refrigerant that has passed through the heating unit to the accumulator;
a bypass flow path that guides the refrigerant discharged from the compressor to the accumulator without passing through the heating unit;
a first throttle mechanism arranged in the circulation flow path and decompressing the refrigerant flowing out from the heating unit;
a second throttle mechanism arranged in the bypass flow path for decompressing the refrigerant discharged from the compressor,
a detection step of detecting the pressure of the refrigerant sucked by the compressor;
When the pressure of the refrigerant detected by the detection step is lower than a predetermined pressure, inflowing refrigerant flowing into the accumulator containing the refrigerant decompressed by the first throttle mechanism and the refrigerant decompressed by the second throttle mechanism control the first opening degree of the first throttle mechanism and the second opening degree of the second throttle mechanism so that the ratio of the gas refrigerant in the accumulator is greater than the ratio of the gas refrigerant in the refrigerant flowing out from the accumulator a first control step to
When the pressure of the refrigerant detected by the detection step is higher than the predetermined pressure, the ratio of liquid refrigerant in the inflowing refrigerant is greater than the ratio of liquid refrigerant in the outflowing refrigerant flowing out of the accumulator. and a second control step of controlling the first degree of opening and the second degree of opening.