JP3436670B2 - Air conditioner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly to control of a bypass circuit during heating operation.

[0002]

2. Description of the Related Art FIG. 8 shows, for example, JP-A-63-23325.
Fig. 6 shows a refrigerant circuit configuration of a conventional air conditioner braking device shown in Japanese Patent Publication No. In the figure, 1 is a compressor that compresses and discharges a refrigerant, 2 is a four-way valve that switches the flow path of the refrigerant from this compressor 1, 3 is an outdoor heat exchanger, 4 is an electric expansion valve, and 5 is indoor heat exchange. It is a vessel. The compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the electric expansion valve 4, and the indoor heat exchanger 5 are sequentially connected by a refrigerant pipe 6 to form a refrigerant circuit. A bypass pipe 7 connects the discharge-side high-pressure pipe 6a and the suction-side low-pressure pipe 6b of the compressor 1. Reference numeral 8 is a solenoid valve disposed in the middle of the bypass pipe 7, reference numeral 9 is a control unit for operating a control device of an indoor / outdoor unit including the solenoid valve 8, and 10 is a detector for detecting the discharged refrigerant gas temperature.

Next, the operation will be described. During the heating operation, the refrigerant is sent from the compressor 1 through the four-way valve 2 to the indoor heat exchanger 5, condensed and liquefied, then decompressed by the electric expansion valve 4, and evaporated by the outdoor heat exchanger 3. It becomes a gas refrigerant and returns to the compressor 1 through the four-way valve 2.

When the temperature of the discharged refrigerant gas rises above the set temperature which seems to be abnormal in the state where the heating operation cycle is formed as described above, the control unit 9 detects this by the detector 10. Then, the control unit 9 controls so that the electromagnetic valve 8 of the bypass pipe 7 which has been closed until now is simultaneously opened. By performing these controls,
A part of the refrigerant gas discharged from the compressor 1 is a bypass pipe 7
Through the low pressure side pipe 6b and the discharge pipe 6a
The heating operation cycle is continued without increasing the pressure.

[0005]

Since the conventional control device for the air conditioner is constructed as described above, the compressor or other refrigerant circuit parts are controlled by the compressor discharge temperature or the compressor discharge pressure during heating operation. However, there is a problem that an expensive pressure detector is necessary for detecting the compressor discharge pressure.

In addition, if the pressure detector for detecting the discharge pressure of the compressor malfunctions, the operating range of the air conditioner cannot be expanded.

The present invention has been made in order to solve the above problems, and is inexpensive and highly reliable by detecting the temperature of an indoor heat exchanger. It is an object of the present invention to provide an air conditioner control device capable of expanding an operating range.

[0008]

An air conditioner according to the present invention comprises a compressor, a four-way valve, an outdoor heat exchanger, an outdoor pressure reducing means in which an outdoor check valve is connected in parallel, and an indoor check valve. Are connected in parallel to the indoor side pressure reducing means, a refrigeration cycle in which the indoor heat exchangers are sequentially connected, a refrigerant pipe connecting the outdoor side pressure reducing means and the indoor side pressure reducing means, and from the discharge side of the compressor to the refrigerant pipe. A bypass circuit connected via a solenoid valve, an indoor heat exchanger temperature detecting means for detecting the temperature of the indoor heat exchanger,
The compressor discharge temperature detecting means for detecting the discharge temperature of the compressor and the indoor heat exchanger temperature detected by the indoor heat exchanger temperature detecting means during the heating operation are the predetermined temperature T at which the compressor stops abnormally.
Before reaching i0, a predetermined temperature T lower than the predetermined temperature Ti0
i1 or when the compressor discharge temperature detected by the compressor discharge temperature detection means reaches a predetermined temperature To1 lower than the predetermined temperature To0 before reaching the predetermined temperature To0 at which the compressor abnormally stops. Control means for opening the solenoid valve,
Equipped with a control means, after opening the solenoid valve, the indoor heat exchange
The indoor heat exchanger temperature detected by the unit temperature detection means is the specified temperature.
When a predetermined temperature Ti0 higher than Ti1 is reached, or
The compressor discharge temperature detected by the compressor discharge pipe temperature detection means is
When a predetermined temperature To0 higher than the predetermined temperature To1 is reached
Stop the compressor, and the indoor heat exchanger temperature detection means detects
Place where the temperature of the indoor heat exchanger is lower than the specified temperature Ti1
Detects the temperature of the compressor discharge pipe at a constant temperature of Ti2 or less
The compressor discharge temperature detected by the means is lower than the predetermined temperature To1.
The solenoid valve is closed when the temperature reaches a low predetermined temperature To2 .

Further, in the air conditioner according to the present invention, the compressor, the four-way valve, the outdoor heat exchanger, the outdoor decompression means in which the outdoor check valve is connected in parallel, and the indoor check valve are connected in parallel. A refrigeration cycle in which the indoor side pressure reducing means and the indoor heat exchanger are sequentially connected, a refrigerant pipe connecting the outdoor side pressure reducing means and the indoor side pressure reducing means, and an electromagnetic valve from the discharge side of the compressor to the refrigerant pipe. Connected bypass circuit, indoor heat exchanger temperature detection means for detecting the temperature of the indoor heat exchanger, compressor discharge temperature detection means for detecting the discharge temperature of the compressor, and discharge pressure of the compressor A predetermined value lower than the predetermined temperature Ti0 before the indoor heat exchanger temperature detected by the compressor discharge pressure detection means and the indoor heat exchanger temperature detection means during the heating operation reaches a predetermined temperature Ti0 at which the compressor abnormally stops. When temperature Ti1 is reached or compression When the compressor discharge temperature detected by the discharge temperature detecting means reaches a predetermined temperature To1 lower than the predetermined temperature To0 before reaching the predetermined temperature To0 at which the compressor abnormally stops, or the compressor discharge pressure detecting means detects the temperature. discharge pressure that is, before the compressor reaches a predetermined temperature P0 to abnormal stop, and a control means for opening the solenoid valve when it reaches a predetermined pressure P1 is lower than the predetermined temperature P0, the control means
After opening the solenoid valve, the indoor heat exchanger temperature detection means
The detected indoor heat exchanger temperature is higher than the predetermined temperature Ti1.
When the temperature reaches the specified temperature Ti0, or the compressor discharge pipe temperature
The compressor discharge temperature detected by the detection means is the predetermined temperature To1.
When the temperature reaches a higher temperature To0, which is higher than
The discharge pressure detected by the pressure detection means is higher than the predetermined pressure P1.
When the high predetermined pressure P0 is reached, the compressor is stopped, and
Indoor heat exchanger temperature detected by the indoor heat exchanger temperature detection means
Is below a predetermined temperature Ti2 lower than the predetermined temperature Ti1.
Compressor detected by the compressor discharge pipe temperature detection means
A predetermined temperature To2 whose discharge temperature is lower than the predetermined temperature To1
And the discharge pressure detected by the compressor discharge pressure detection means
When a predetermined pressure P2 lower than the predetermined pressure P1 is reached
It closes the solenoid valve .

[0010]

[0011]

[0012]

[0013]

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an example of an embodiment of the present invention.
It is a block diagram which shows the principle structure of the control apparatus of an air conditioner. In the figure, 11 is an operation command input means that operates according to ON / OFF of the operation command input from the input terminal 11a, 17 is an indoor heat exchanger temperature detecting means that detects the temperature of the indoor heat exchanger from the thermistor 18, and 19 Is a compressor discharge temperature detecting means for detecting the temperature of the compressor discharge pipe from the thermistor 10.

Reference numeral 14 denotes the compressor 1, based on the output signal from the operation command input means 11 and the output signal from the indoor heat exchanger temperature detection means 17 or the compressor discharge temperature detection means 19.
It is a control means for operating / stopping an electric device such as the solenoid valve 8, a self-holding / inspection mode when an abnormality occurs, and a restart control. The control means 14 is connected to a compressor drive means 1a controlled by its command output, a display drive means 15 and an electromagnetic valve drive means 8a, and the compressor drive means 1a is connected to the compressor 1. The solenoid valve 8 is connected to the solenoid valve drive means 8 a, and the display drive means 15 is connected to a display 16 for displaying an abnormality.

FIG. 2 is a block diagram of the refrigeration cycle of the air conditioner of FIG. In FIG. 2, 1 is a compressor that compresses and discharges the refrigerant, 2 is a four-way valve that switches the flow path of the refrigerant from the compressor 1, 3 is an outdoor heat exchanger, and 4 is provided outside and inside the room, respectively. The outdoor side decompression device and the decompression device which are the indoor decompression device, 23 is a check valve that is an outdoor side check valve and an indoor side check valve connected in parallel to the decompression device 4, and 5 is an indoor heat exchanger Is. These are sequentially connected by the refrigerant pipe 6 to form a refrigerant circuit of the air conditioner. Reference numeral 10 denotes a refrigerant pipe 6a near the compressor 1.
, 18 is a thermistor installed in the refrigerant pipe in the vicinity of the indoor heat exchanger 5, and 7 is a refrigerant pipe that connects the discharge side of the compressor 1 to the indoor decompression device 4 and the outdoor heat exchanger 3. By-pass piping connected to 6 parts, 8
Is a solenoid valve disposed in the bypass pipe 7 portion.

The operation of the air conditioner configured as above will be described below. During the heating operation, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 is supplied to the indoor heat exchanger 5 via the four-way valve 2 to exchange heat with the indoor air and condense for heating. It becomes the liquid refrigerant of. Next, this high-pressure liquid refrigerant is decompressed by passing through the decompression device 4 on the indoor side, and in the process of passing through the outdoor heat exchanger 3, it is heat-exchanged with the outdoor air to be evaporated and become a low-pressure refrigerant gas. . Then, this low-pressure refrigerant gas is sucked into the compressor 1 via the four-way valve 2.

Here, in the heating operation mode, the input terminal 11
When the operation ON command is input to a, the operation command input means 11
An operation ON command signal is output from the control unit 14 and is taken into the control means 14. The control unit 14 outputs an operation command to the compressor driving unit 1a in response to the operation ON command signal, and by operating this, power is supplied to the electric compressor 1, and the compressor 1 is operated to operate the refrigeration cycle. To operate the air conditioner.

In this heating operation state, the thermistor 1
The temperature of the indoor heat exchanger 5 by 8 or the temperature of the compressor 1 discharge by the thermistor 10 is measured by the indoor heat exchanger temperature detecting means 17
Alternatively, it is detected by the compressor discharge temperature detection means 19, and an output signal is sent to the control means 14. Before the temperature of the indoor heat exchanger 5 or the discharge temperature of the compressor 1 reaches a second set value at which the control means 14 abnormally stops, the temperature of the indoor heat exchanger 5 or the discharge temperature of the compressor 1 becomes the first value. When the set value is reached, it is output to the solenoid valve drive means 8a to open the solenoid valve 8.

The operation when the solenoid valve 8 provided in a part of the bypass pipe 7 is open will be described with reference to the characteristic diagram shown in FIG. In FIG. 4, the vertical axis represents pressure P
(kg / cm2) and the horizontal axis is the mortal diagram showing enthalpy (kcal / kg). The solid line indicates a normal cycle in which the solenoid valve 8 is closed, and the alternate long and short dash line indicates that the solenoid valve 8 is open. It shows the cycle. Also, A and a in the figure are compressors 1.
Of B, b is the discharge state of the compressor, C and c are the outlet states of the indoor heat exchanger 5, D and d are the outlet states of the pressure reducing means 4, and E and e are the inlet states of the outdoor heat exchanger 3. Respectively, A to E are when the solenoid valve 8 is closed, and a to e are when the solenoid valve 8 is open.

When the solenoid valve 8 is opened, a part of the high-temperature high-pressure refrigerant gas discharged from the compressor 1 (state b) passes through the bypass pipe 7 and is decompressed by the decompression means 4 to form a low-pressure refrigerant gas. Mixing with (state of d), the state becomes e, the enthalpy becomes larger than the state of E without the bypass pipe 7, and the outdoor heat exchanger 3 evaporates. Rises.

On the other hand, the remaining high-temperature and high-pressure refrigerant gas discharged from the compressor 1 condenses in the indoor heat exchanger 5, but the condensation and refrigerant flow rates are smaller than in the case without the bypass pipe 7. Moreover, the condensation temperature and pressure are reduced.
That is, by bypassing, the condensing capacity and the evaporating capacity are reduced, so that there is an effect of expanding the operation range without abnormally stopping the air conditioner under the overload condition during the heating operation.

By detecting the temperature of the indoor heat exchanger, the condensing temperature and the value of the condensing pressure have a constant relationship, so that not only the condensing temperature of the indoor heat exchanger 5 but also the condensing pressure can be detected. Since the compressor discharge pressure can be predicted from the relationship of condensing pressure ≒ compressor discharge pressure, the indoor heat exchanger temperature detecting means can be substituted without using the compressor discharge pressure detecting means, and a cheaper component can be obtained. A control means is obtained using.

Next, the operation of the air conditioner will be described based on the flow chart shown in FIG. First step 31
In the heating operation mode. In the next step 32, the control means 14 sends an output signal to the solenoid valve drive means 8a to close the solenoid valve 8. In the next step 33, it is determined whether or not a driving command is input from the input terminal 11a. If the operation command signal is OFF, the routine proceeds to step 43, the compressor is stopped and the routine proceeds to step 44 stop mode. If the operation command signal is ON, the routine proceeds to step 34, where the control means 14 causes the compressor drive means 1 to operate.
By sending an output signal to a, power is supplied to the compressor 1, and the compressor 1 is driven to start the operation of the air conditioner. Then, the process proceeds to the next step 55. In step 55, the temperature of the indoor heat exchanger 5 is detected by the indoor heat exchanger temperature detecting means 17 by the thermistor 18, and the refrigerant pipe 6 near the compressor 1 is detected by the thermistor 10.
The temperature of a is detected by the compressor discharge temperature detecting means 19,
The output signal is sent to the control means 14 and the routine proceeds to step 56.

In the next step 56, the control means 14 compares the temperature Ti of the indoor heat exchanger 5 with the predetermined temperature Ti1 and the temperature To of the discharge pipe To with the predetermined temperature To1 and Ti> T
It is determined whether i1 or To> To1. Then, if the determination in step 56 is NO, the process returns to step 33. If the determination in step 56 is YES, the process proceeds to step 37. In the next step 37, the control means 14 causes the solenoid valve drive means 8a to be operated.
To open the solenoid valve 8 and proceed to the next step 58. In the next step 58, the temperature of the indoor heat exchanger 5 is detected by the indoor heat exchanger temperature detecting means 17 by the thermistor 18, and the temperature of the refrigerant pipe 6a near the compressor 1 is detected by the thermistor 10 by the compressor discharge temperature detecting means 19. Detect and send output signal to control means 14 Step 5
Proceed to 9.

In the next step 59, the control means 14 compares the temperature Ti of the indoor heat exchanger 5 with the predetermined temperature Ti0 and the temperature To of the discharge pipe with the predetermined temperature To0, and Ti>
It is determined whether Ti0 or To> To0. Then, if the determination in step 59 is YES, it is determined that the protective device is activated, and the process proceeds to step 45. The predetermined temperatures To0, Ti0 and the predetermined temperatures To1, Ti1
The magnitude relationship with is To0> To1 and Ti0> T, respectively.
i1.

In the next step 45, the control means 14 outputs a stop command to the compressor driving means 1a to stop the operation of the compressor 1 and the operation proceeds to step 46. In step 46, the control means 14 outputs to the abnormality display driving means 15, the display 16 is turned on to display an abnormality, and the process proceeds to the next step 47 inspection mode. Further, the determination in step 59 is NO.
If so, the process proceeds to step 60. Next step 60
Then, the thermistor 18 detects the temperature of the indoor heat exchanger 5 by the indoor heat exchanger temperature detecting means 17, and the thermistor 10 detects the temperature of the refrigerant pipe 6a near the compressor 1 by the compressor discharge temperature detecting means 19 to output A signal is sent to the control means 14 and the routine proceeds to step 61.

In the next step 61, the control means 14 compares the temperature Ti of the indoor heat exchanger 5 with the predetermined temperature Ti2 and the temperature To of the discharge pipe To with the predetermined temperature To2, and Ti≤
It is determined whether Ti2 and To ≦ To2. Then, if the determination in step 61 is NO, the process returns to step 58. If the determination in step 61 is YES, the process proceeds to step 42. In the next step 42, the control means 14 causes the solenoid valve drive means 8a to be operated.
To the electromagnetic valve 8 to close it and return to step 33. The predetermined temperatures To2, Ti2 and the predetermined temperatures To1,
The magnitude relationship with Ti1 is To1> To2, Ti, respectively.
1> Ti2.

Therefore, by detecting the temperature of the indoor heat exchanger or the discharge temperature of the compressor, the bypass circuit connected from the discharge side of the compressor to the refrigerant pipe portion connecting the pressure reducing means and the outdoor heat exchanger is opened and closed. It is possible to prevent the protection device from operating under an overload condition and to expand the operating range of the air conditioner. Further, by detecting the temperature of the indoor unit heat exchanger, the condensing temperature and the value of the condensing pressure have a constant relationship, so that not only the condensing temperature of the indoor heat exchanger but also the condensing pressure can be detected. Here, since the compressor discharge pressure can be predicted from the relationship of condensation pressure ≈ compressor discharge pressure, the indoor unit heat exchanger temperature means can be substituted without using the compressor discharge pressure detection means, and cheaper parts can be used. The operating range of the air conditioner can be expanded.

Embodiment 2. Hereinafter, another example of the embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a diagram showing another example of the embodiment of the present invention, and is a block diagram showing a principle configuration of a control device for an air conditioner. In addition to the configuration of FIG. 1, compressor discharge pressure detection means 2 for detecting the compressor discharge pressure from the pressure sensor 22.
1 has been added.

FIG. 6 is a block diagram of the refrigeration cycle of the air conditioner of FIG. In addition to the configuration of FIG. 2, a pressure sensor 22 installed on the refrigerant pipe 6a near the compressor 1 is added.

The operation of the air conditioner constructed as above will be described below. During the heating operation, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 is supplied to the indoor heat exchanger 5 via the four-way valve 2 to exchange heat with the indoor air and be condensed to heat the indoor air. It becomes the liquid refrigerant of. Next, this high-pressure liquid refrigerant is decompressed by passing through the decompression device 4 on the indoor side, and in the process of passing through the outdoor heat exchanger 3, it is heat-exchanged with the outdoor air to be evaporated and become a low-pressure refrigerant gas. . Then, this low-pressure refrigerant gas is sucked into the compressor 1 via the four-way valve 2.

Here, the input terminal 11a in the heating operation mode
When a driving ON command is input to the driving command input means 11, a driving ON command signal is output from the driving command input means 11 and is taken into the control means 14. The control unit 14 outputs an operation command to the compressor driving unit 1a in response to the operation ON command signal, and by operating this, power is supplied to the compressor 1, and the compressor 1 is operated to start the refrigeration cycle. Form and operate the air conditioner.

In this heating operation state, the thermistor 1
8, the temperature of the indoor heat exchanger 5 is detected by the indoor heat exchanger temperature detecting means 17, the temperature of the compressor discharge by the thermistor 10 is detected by the compressor discharge temperature detecting means 19, or the compressor discharge pressure by the pressure sensor 22 is compressed. It is detected by the machine discharge pressure detection means 21 and an output signal is sent to the control means 14. The control means causes the temperature of the indoor heat exchanger 5 or the discharge temperature or discharge pressure of the compressor 1 to reach the second set value at which the temperature of the indoor heat exchanger 5 or the discharge pressure of the compressor 1 stops abnormally before reaching the second set value. When the pressure reaches the first set value, the pressure is output to the solenoid valve drive means 8a to open the solenoid valve 8.

The operation when the solenoid valve 8 provided in a part of the bypass pipe 7 is open will be described with reference to the characteristic diagram shown in FIG. In FIG. 4, the vertical axis represents pressure P
(kg / cm2), the horizontal axis is the enthalpy (kcal / kg) Mollier diagram, the solid line is the normal cycle where the solenoid valve 8 is closed, and the dashed line is the solenoid valve 8 is open. It shows the cycle. Also, A and a in the figure are compressors 1.
Of B, b is the discharge state of the compressor, C and c are the outlet states of the indoor heat exchanger 5, D and d are the outlet states of the pressure reducing means 4, and E and e are the inlet states of the outdoor heat exchanger 3. Respectively, A to E are when the solenoid valve 8 is closed, and a to e are when the solenoid valve 8 is open. When the solenoid valve 8 is opened, a part of the high-temperature high-pressure refrigerant gas (state of b) discharged from the compressor 1 passes through the bypass pipe 7 and the low-pressure refrigerant gas (d of State), the state becomes e, the enthalpy becomes larger than the state E in which the bypass pipe 7 is not present, and the outdoor heat exchanger 3 evaporates, so that the evaporation temperature and the pressure rise. .

On the other hand, the remaining high-temperature and high-pressure refrigerant gas discharged from the compressor 1 is condensed in the indoor heat exchanger 5, but the condensation and refrigerant flow rates are smaller than in the case without the bypass pipe 7. Moreover, the condensation temperature and pressure are reduced.
That is, by bypassing, the condensing capacity and the evaporating capacity are reduced, so that there is an effect of expanding the operation range without abnormally stopping the air conditioner under the overload condition during the heating operation.

By detecting the temperature of the indoor unit heat exchanger, the condensing temperature and the value of the condensing pressure have a constant relationship, so that not only the condensing temperature of the indoor heat exchanger but also the condensing pressure can be detected. Here, from the relationship of condensing pressure ≒ compressor discharge pressure,
Since the compressor discharge pressure can be predicted, even if the pressure detection means malfunctions, the indoor unit heat exchanger temperature means can detect the condensation temperature / pressure and the compressor discharge pressure, and a more reliable control means. Is obtained.

Next, the operation of the air conditioner will be described with reference to the flow chart shown in FIG. First step 31
In the heating operation mode. In the next step 32, the control means 14 sends an output signal to the solenoid valve drive means 8a to close the solenoid valve 8. In the next step 33, it is determined whether or not a driving command is input from the input terminal 11a. If the operation command signal is OFF, the routine proceeds to step 43, the compressor is stopped and the routine proceeds to step 44 stop mode. If the operation command signal is ON, the routine proceeds to step 34, where the control means 14 causes the compressor drive means 1 to operate.
By sending an output signal to a, power is supplied to the compressor 1, and the compressor 1 is driven to start the operation of the air conditioner. Then, the process proceeds to the next step 35.

In step 35, the temperature of the indoor heat exchanger 5 is controlled by the thermistor 18 to detect the indoor heat exchanger temperature 17.
Is detected by the thermistor 10, and the temperature of the refrigerant pipe 6a in the vicinity of the compressor is detected by the thermistor 10.
Is detected by the pressure sensor 22, and the pressure of the refrigerant pipe 6a near the compressor is detected by the pressure sensor 22.
1 and sends the output signal to the control means 14 and proceeds to step 36. In the next step 36, the control means 14 causes the temperature Ti of the indoor heat exchanger 5 and the predetermined temperature Ti1, the temperature To of the discharge pipe To and the predetermined temperature To1, and the pressure P of the discharge pipe.
And a predetermined pressure P1 are compared, and Ti> Ti1 or To> T
It is determined whether or not o1 or P> P1. And
When the determination in step 36 is NO, the process returns to step 33. If the determination in step 36 is YES, the process proceeds to step 37.

In the next step 37, the control means 14 outputs to the solenoid valve drive means 8a to open the solenoid valve 8 and the process proceeds to the next step 38. In the next step 38, the thermistor 1
8, the temperature of the indoor heat exchanger 5 is detected by the indoor heat exchanger temperature detecting means 17, the temperature of the refrigerant pipe 6a near the compressor is detected by the thermistor 10 by the compressor discharge temperature detecting means 19, and the pressure sensor 22 is used. The pressure in the refrigerant pipe 6a near the compressor is detected by the compressor discharge pressure detection means 21, and an output signal is sent to the control means 14 to proceed to step 39.

In the next step 39, the control means 14 causes the temperature Ti of the indoor heat exchanger 5 and the predetermined temperature Ti0, the temperature To of the discharge pipe and the predetermined temperature To0, and the pressure P of the discharge pipe.
Is compared with a predetermined pressure P0, and Ti> Ti0 or To> T
It is determined whether or not o0 or P> P0. And
When the determination in step 39 is YES, it is determined that the protective device is activated, and the process proceeds to step 45. In the next step 45, the control means 14 outputs a stop command to the compressor driving means 1a to stop the operation of the compressor 1 and the operation proceeds to step 46. In step 46, the control means 14 outputs to the abnormality display driving means 15, the display 16 is turned on to display an abnormality, and the process proceeds to the next step 47 inspection mode. Also,
When the determination in step 39 is NO, the process proceeds to step 40.

In the next step 40, the thermistor 18 detects the temperature of the indoor heat exchanger 5 by the indoor heat exchanger temperature detecting means 17, and the thermistor 10 detects the temperature of the refrigerant pipe 6a near the compressor in the compressor discharge temperature detecting means. 19, the pressure sensor 22 detects the pressure of the refrigerant pipe 6a near the compressor by the compressor discharge pressure detection means 21, sends an output signal to the control means 14, and proceeds to step 41.

In the next step 41, the control means 14 causes the temperature Ti of the indoor heat exchanger 5 and the predetermined temperature Ti2, the temperature To of the discharge pipe and the predetermined temperature To2, and the pressure P of the discharge pipe.
Is compared with a predetermined pressure P2, and Ti ≦ Ti2 and To ≦ T
It is determined whether or not o2 and P ≦ P2. And
If the determination in step 41 is NO, the process returns to step 38. If the determination in step 41 is YES, the process proceeds to step 42. In the next step 42, the control means 14 sends an output signal to the solenoid valve driving means 8a to close the solenoid valve 8 and the process returns to step 33.

Therefore, during heating operation, by detecting not only the compressor discharge temperature and discharge pressure but also the indoor heat exchanger temperature, even if the discharge pressure pressure detection means malfunctions, the condensation temperature and condensation Incorporating pressure into the control factor,
By opening and closing the bypass circuit connected from the discharge side of the compressor to the refrigerant pipe portion connecting the pressure reducing means 4 and the outdoor heat exchanger 3, the protection device is prevented from operating under an overload condition, and the air conditioner The function of expanding the operating range,
It can be performed with higher accuracy.

[0045]

In the air conditioner according to the present invention, during the heating operation, the indoor heat exchanger temperature detected by the indoor heat exchanger temperature detecting means reaches a predetermined temperature Ti0 before the compressor stops abnormally. When the temperature reaches a predetermined temperature Ti1 lower than the temperature Ti0 or before the compressor discharge temperature detected by the compressor discharge temperature detection means reaches a predetermined temperature To0 at which the compressor abnormally stops, a predetermined temperature lower than the predetermined temperature To0. By opening the solenoid valve when the temperature To1 is reached, it is possible to prevent the protection device from operating under an overload condition and to expand the operating range of the heating operation of the air conditioner at low cost. Also the room
If the indoor heat exchanger temperature detected by the internal heat exchanger temperature detection means is
The temperature becomes equal to or lower than a predetermined temperature Ti2 lower than the predetermined temperature Ti1,
And the compressor discharge detected by the compressor discharge pipe temperature detection means
The temperature becomes a predetermined temperature To2 lower than the predetermined temperature To1.
If the solenoid valve is closed, the ability is restored.
Can be planned.

Further, in the air conditioner according to the present invention, during the heating operation, the indoor heat exchanger temperature detected by the indoor heat exchanger temperature detecting means is set to the predetermined temperature Ti0 before the compressor stops abnormally. When the temperature reaches a predetermined temperature Ti1 lower than the temperature Ti0 or before the compressor discharge temperature detected by the compressor discharge temperature detection means reaches a predetermined temperature To0 at which the compressor abnormally stops, a predetermined temperature lower than the predetermined temperature To0. When the temperature To1 is reached or the discharge pressure detected by the compressor discharge pressure detection means reaches a predetermined pressure P1 lower than the predetermined temperature P0 before reaching the predetermined temperature P0 at which the compressor stops abnormally, By opening the solenoid valve, even if the compressor discharge pressure detection means malfunctions, the protective device is not activated under overload conditions, ensuring the operating range of the heating operation of the air conditioner. It can be large is. Also indoors
The indoor heat exchanger temperature detected by the heat exchanger temperature detection means is
Is the temperature below Ti2, which is lower than the constant temperature Ti1,
Compressor discharge temperature detected by the compressor discharge pipe temperature detection means
The temperature becomes a predetermined temperature To2 lower than the predetermined temperature To1.
In some cases, the solenoid valve is closed to restore the capacity.
You can

[0047]

[0048]

[Brief description of drawings]

FIG. 1 is a diagram illustrating an example of an embodiment of the present invention, and is a block diagram illustrating a principle configuration of a control device for an air conditioner.

FIG. 2 is a diagram showing an example of an embodiment of the present invention and is a refrigeration cycle configuration diagram.

FIG. 3 is a diagram showing an example of the embodiment of the present invention, and is a flow chart showing the operation.

FIG. 4 is a Mollier diagram for explaining the operation of the embodiment of the present invention.

FIG. 5 is a diagram showing another example of the embodiment of the present invention,
It is a block diagram which shows the principle structure of the control apparatus of an air conditioner.

FIG. 6 is a diagram showing another example of the embodiment of the present invention,
It is a refrigerating-cycle block diagram.

FIG. 7 is a diagram showing another example of the embodiment of the present invention,
It is a flowchart figure which shows operation.

FIG. 8 is a refrigerant circuit configuration diagram showing a conventional air conditioner braking device.

[Explanation of symbols]

1 compressor, 1a compressor driving means, 2 four-way valve, 3
Outdoor heat exchanger, 4 pressure reducing device, 5 indoor heat exchanger, 6
Refrigerant pipe, 7 bypass pipe, 8 solenoid valve, 8a solenoid valve drive means, 10 thermistor, 11 operation command input means, 11a input terminal, 14 control means, 15 display drive means, 16 indicator, 17 indoor heat exchanger temperature detection Means, 18 Thermistor, 19 Compressor discharge temperature detecting means, 21 Compressor discharge pressure detecting means, 22 Pressure sensor, 23 Check valve.

Front page continuation (72) Inventor Takeshi Kosai 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (56) Reference JP-A-1-260266 (JP, A) JP-A-5-264107 ( JP, A) Actual Kaihei 4-46668 (JP, U) Japanese Patent Publication 53-21134 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) F25B 1/00 101 F25B 1 / 00 341

Claims (2)

(57) [Claims] 1. A compressor, a four-way valve, an outdoor heat exchanger, an outdoor pressure reducing means in which an outdoor check valve is connected in parallel, an indoor pressure reducing means in which an indoor check valve is connected in parallel, and indoor heat. A refrigeration cycle in which exchangers are sequentially connected, a refrigerant pipe connecting the outdoor decompression unit and the indoor decompression unit, and a bypass connected from the discharge side of the compressor to the refrigerant pipe via an electromagnetic valve. A circuit, an indoor heat exchanger temperature detection means for detecting the temperature of the indoor heat exchanger, a compressor discharge temperature detection means for detecting the discharge temperature of the compressor, and the indoor heat exchanger temperature detection during heating operation If the indoor heat exchanger temperature detected by the means reaches a predetermined temperature Ti1 lower than the predetermined temperature Ti0 before reaching the predetermined temperature Ti0 at which the compressor abnormally stops, or the compressor discharge temperature detection means The compressor detected by Out temperature, the before the compressor reaches a predetermined temperature To0 to abnormal stop, and a control means for opening said solenoid valve when it reaches a predetermined temperature To0 predetermined temperature To1 lower than the control hand
After opening the solenoid valve, the stage is the temperature of the indoor heat exchanger.
The indoor heat exchanger temperature detected by the detection means is the predetermined temperature.
When a predetermined temperature Ti0 higher than Ti1 is reached, or
The compressor detected by the compressor discharge pipe temperature detecting means
The discharge temperature is a predetermined temperature To which is higher than the predetermined temperature To1.
When it reaches 0, the compressor is stopped and the indoor heat
If the indoor heat exchanger temperature detected by the exchanger temperature detecting means is
Below a predetermined temperature Ti2 lower than the predetermined temperature Ti1
And before the compressor discharge pipe temperature detection means detects
The compressor discharge temperature is lower than the predetermined temperature To1
An air conditioner characterized by closing the solenoid valve when the temperature reaches To2 . 2. A compressor, a four-way valve, an outdoor heat exchanger, an outdoor pressure reducing means in which an outdoor check valve is connected in parallel, an indoor pressure reducing means in which an indoor check valve is connected in parallel, and indoor heat. A refrigeration cycle in which exchangers are sequentially connected, a refrigerant pipe connecting the outdoor decompression unit and the indoor decompression unit, and a bypass connected from the discharge side of the compressor to the refrigerant pipe via an electromagnetic valve. A circuit, an indoor heat exchanger temperature detecting means for detecting the temperature of the indoor heat exchanger, a compressor discharge temperature detecting means for detecting the discharge temperature of the compressor, and a compressor for detecting the discharge pressure of the compressor Before the discharge pressure detecting means and the indoor heat exchanger temperature detected by the indoor heat exchanger temperature detecting means during the heating operation reach the predetermined temperature Ti0 at which the compressor abnormally stops, the temperature is higher than the predetermined temperature Ti0. Reached a low predetermined temperature Ti1 Or when the compressor discharge temperature detected by the compressor discharge temperature detecting means reaches a predetermined temperature To1 lower than the predetermined temperature To0 before reaching the predetermined temperature To0 at which the compressor abnormally stops, Or, the discharge pressure detected by the compressor discharge pressure detection means,
Wherein before the compressor reaches a predetermined temperature P0 to abnormal stop, and a control means for opening said solenoid valve when it reaches a predetermined temperature P0 predetermined pressure P1 is lower than the control
The means is to open the solenoid valve, and then set the indoor heat exchanger temperature.
The indoor heat exchanger temperature detected by the temperature detection means is the predetermined value.
When a predetermined temperature Ti0 higher than the temperature Ti1 is reached,
Is the compression detected by the compressor discharge pipe temperature detecting means.
A predetermined temperature T at which the machine discharge temperature is higher than the predetermined temperature To1
When it reaches 0, or the compressor discharge pressure detection means
A predetermined pressure at which the detected discharge pressure is higher than the predetermined pressure P1.
When the force P0 is reached, the compressor is stopped and the chamber
The indoor heat exchanger temperature detected by the internal heat exchanger temperature detection means
The temperature is less than a predetermined temperature Ti2 lower than the predetermined temperature Ti1
And the compressor discharge pipe temperature detection means detects
The compressor discharge temperature is lower than the predetermined temperature To1.
A predetermined temperature To2 is reached, and the compressor discharge pressure is detected.
Where the discharge pressure detected by the stage is lower than the predetermined pressure P1
An air conditioner characterized by closing the solenoid valve when a constant pressure P2 is reached .