JPH06337174A - Operation controller for air-conditioner - Google Patents

Abstract

PURPOSE:To prevent the backing of liquid at the time of starting heating operation, the lowering of concentration of lube oil and the lowering of low-pressure refrigerant pressure. CONSTITUTION:A low pressure sensor P2, detecting a low-pressure refrigerant pressure in the suction side of a compressor 21, and a start control means 52, controlling the opening degree of an outdoor motor-driven expansion valve 25 at a set starting degree upon starting heating operation, are provided. Further, when the low-pressure refrigerant pressure is higher than a specific pressure based on the low-pressure refrigerant pressure detected by the low pressure sensor P2, the start control means 52 outputs a closing operation signal so as to make the opening degree of the outdoor motor-driven expansion valve 25 smaller than the opening degree of starting while an opening degree regulating means 53, outputting an opening operation signal so that the start control means 52 increases the opening degree of the outdoor motor-driven expansion valve 25 as the low-pressure refrigerant pressure is reduced than a specific pressure, is provided. In addition, a finishing means 54, finishing the start control of the start control means 52 when a specific time has elapsed from the starting time of the heating operation, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device for an air conditioner, and more particularly to a measure for controlling an expansion valve when starting heating operation.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Publication No.
As disclosed in JP-A-49034, a compressor, a four-way switching valve, an outdoor heat exchanger, an outdoor electric expansion valve, an indoor electric expansion valve, and an indoor heat exchanger are sequentially connected to form a main refrigerant circuit. Has been done. When the air-conditioning operation is started, the initial value of each electric expansion valve is set to a pre-stored opening, and the initial opening is held for a predetermined time. It is controlled according to the cooling degree.

[0003]

However, in the air conditioner described above, the stored data of the initial opening of the electric expansion valve can be rewritten to the opening during stable operation, but the predetermined time is constant. Since the initial opening is fixed, the initial opening may be too large depending on the environmental conditions such as the outside air temperature. That is, for example, at the time of starting the heating operation in low outside air, the liquid refrigerant in the outdoor heat exchanger is difficult to evaporate, and the opening degree during stable operation becomes too large, so that at the outlet side of the outdoor heat exchanger. There is a problem that the refrigerant becomes too wet and liquid back occurs. Further, if the compressor is repeatedly started up many times such as when the thermostat is stopped, the concentration of the lubricating oil in the compressor is reduced, and there is a problem that the bearing is burned with metal.
Therefore, if the initial opening of the electric expansion valve is set to a small value, there is a problem that the low-pressure refrigerant pressure decreases and the protection device operates to repeat the retry operation.

The present invention has been made in view of the above problems, and prevents liquid backing at the time of starting the heating operation, prevents a decrease in lubricating oil concentration, and prevents a decrease in low-pressure refrigerant pressure. The purpose is to do.

[0005]

In order to achieve the above object, the means taken by the present invention is to change the starting opening of the expansion valve in accordance with the low pressure refrigerant pressure. Specifically, as shown in FIG. 1, the means taken by the invention according to claim 1 is as follows. First, a compressor (21) and a heat source side heat exchanger (24).
And an expansion valve (25) with adjustable opening and a heat exchanger (31) on the use side
It is intended for an operation control device of an air conditioner in which and are sequentially connected to form a main refrigerant circuit (11) of a closed circuit.
Then, the low pressure detection means (P2) for detecting the low pressure refrigerant pressure on the suction side of the compressor (21) and the opening degree of the expansion valve (25) at the time of starting the heating operation are controlled to a preset opening degree. A start control means (52) is provided. Further, when the low-pressure refrigerant pressure is a predetermined pressure or higher based on the low-pressure refrigerant pressure detected by the low-pressure detection means (P2), the start control means (52)
Outputs a closing motion signal so that the opening degree of the expansion valve (25) is smaller than the starting opening degree, and the starting control means (52) causes the expansion valve (2) as the low-pressure refrigerant pressure falls below a predetermined pressure.
An opening adjustment means (53) for outputting an opening signal to increase the opening of 5) is provided. In addition, a termination means (54) for terminating the activation control of the activation control means (52) when a predetermined time has elapsed from the time of activation of the heating operation is provided.

Further, in the means taken by the invention according to claim 2, the superheat degree of the refrigerant in the heat source side heat exchanger (24) during the heating operation is replaced with the termination means (54) in the invention according to claim 1. Superheat detection means (55) for detecting, and the superheat detection means (55)
When the degree of superheat detected by the
An end means (54a) for ending the startup control of 2) is provided. The means taken by the invention according to claim 3 is the oil temperature detecting means for detecting the lubricating oil temperature in the compressor (21) in place of the ending means (54) in the invention of claim 1.
(Th9) and a termination means (54b) for terminating the activation control of the activation control means (52) when the lubricating oil temperature detected by the oil temperature detection means (Th9) reaches a predetermined temperature. . Further, the means taken by the invention according to claim 4 is, in place of the end means (54) in the invention according to claim 1, superheat for detecting the degree of superheat of the refrigerant in the heat source side heat exchanger (24) during heating operation. Degree detection means (55), oil temperature detection means (Th9) for detecting the lubricating oil temperature in the compressor (21), and the superheat degree detected by the superheat degree detection means (55) reaches a predetermined temperature, and When the lubricating oil temperature detected by the oil temperature detection means (Th9) reaches a predetermined temperature, the end means (54c) for ending the start control of the start control means (52)
And are provided. The means taken by the invention according to claim 5 is the ending means in the invention according to claim 1.
Instead of (54), a discharge pipe temperature detecting means (Th4) for detecting the discharge pipe temperature of the compressor (21), and the discharge pipe temperature detecting means (Th4)
When the discharge pipe temperature detected by the device reaches a predetermined temperature, a termination means (54d) for terminating the activation control of the activation control means (52) is provided.

[0007]

With the above construction, in the invention according to claim 1,
First, when the heating operation is started, the compressor (21) is started, while the start control means (52) controls the expansion valve (25) to the opening degree. Further, the opening adjustment means (53) is a low pressure detection means (P2)
It is determined whether the low pressure refrigerant pressure is low by receiving the detection signal of, and when the low pressure refrigerant pressure is a predetermined low pressure, the start control means (52) reduces the opening degree of the expansion valve (25). It will output a closing signal. After that, when the low-pressure side pressure further decreases, the opening adjustment means (53), the start control means
The (52) outputs an opening signal to increase the opening of the expansion valve (25). That is, the opening degree of the expansion valve (25) is made larger or smaller than the starting opening degree as the low-pressure side pressure decreases or rises. Then, when a predetermined time has elapsed from the time of starting, the end means (54) outputs an end signal to the start control means (52) to end the start control of the expansion valve (25) and perform normal superheat control or the like. Will be controlled.

Further, in the invention according to claim 2, when the degree of superheat of the refrigerant in the heat source side heat exchanger (24) reaches a predetermined temperature,
The termination means (54a) outputs a termination signal to the activation control means (52) to terminate the activation control of the expansion valve (25), and in the invention according to claim 3, the oil temperature in the compressor (21) is When the temperature reaches a predetermined temperature, the end means (54b) outputs an end signal to the start control means (52) to end the start control of the expansion valve (25).
In the invention according to, when the superheat degree of the refrigerant in the heat source side heat exchanger (24) and the oil temperature in the compressor (21) reach a predetermined temperature, the end means (54c) sends an end signal to the start control means (52). Is output, the start control of the expansion valve (25) is terminated, and in the invention according to claim 5, when the discharge pipe temperature of the compressor (21) reaches a predetermined temperature,
The termination means (54d) outputs a termination signal to the activation control means (52) to terminate the activation control of the expansion valve (25).

[0009]

Therefore, according to the invention of claim 1,
In order to reduce the opening degree of the expansion valve (25) at startup depending on the low-pressure refrigerant pressure, for example, when starting the heating operation at low outside air, the liquid refrigerant in the outdoor heat exchanger is Even when it is difficult to evaporate, it is possible to prevent the refrigerant from becoming too wet on the outlet side of the heat source side heat exchanger (24), and it is possible to reliably prevent liquid back. Further, since the liquid back can be prevented, the concentration of the lubricating oil in the compressor (21) does not decrease, and it is possible to reliably secure the oil supply to the metal portion of the bearing. Further, since the opening degree of the expansion valve (25) is adjusted, if the low-pressure refrigerant pressure is too low, the opening degree is increased, so that the protective device does not operate and the retry operation is surely repeated. Can be prevented.

Further, according to the second aspect of the present invention, the start control of the expansion valve (25) is terminated based on the degree of superheat of the heat source side heat exchanger (24). You can start. Further, according to the invention of claim 3, since the start control of the expansion valve (25) is terminated based on the oil temperature in the compressor (21), the normal control can be started quickly and the oil Since only the temperature is detected, the starting control can be performed with a small number of detecting means. Further, according to the invention of claim 4, since the start control of the expansion valve (25) is terminated based on the superheat degree of the heat source side heat exchanger (24) and the oil temperature in the compressor (21), The control can be started quickly and the liquid back can be surely prevented.
Further, according to the invention of claim 5, since the start control of the expansion valve (25) is terminated based on the discharge pipe temperature of the compressor (21), the normal control can be started quickly and Since it is possible to use the discharge pipe detection means that can also be used for the control, it is possible to prevent an increase in the number of parts.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 is an air conditioner according to the present invention.
The refrigerant piping system of the outdoor unit (2) and the indoor unit (3) in (1) is shown. The outdoor unit (2) includes a compressor (21) whose capacity is adjusted by an inverter (2a) whose output frequency is variably switched every 4 to 10 Hz within a range of 30 to 116 Hz, and a compressor (21). An oil separator (22) that separates the oil in the discharged gas, a four-way switching valve (23) that switches as shown by the solid line in the figure during cooling operation and switches as shown by the broken line in the figure during heating operation, and during cooling operation. An outdoor fan (2F) attached to the condenser, the outdoor heat exchanger (24) and the outdoor heat exchanger (24) as a heat source side heat exchanger that serves as an evaporator during heating operation,
An outdoor electric expansion valve (25) that adjusts the refrigerant flow rate during cooling operation and throttles the refrigerant during heating operation, a receiver (26) that stores liquefied refrigerant, and an accumulator (27) are built-in as main equipment. In addition, each device such as the compressor (21) and the outdoor heat exchanger (24) is connected to the refrigerant pipe (4) so that the refrigerant can flow therethrough. Also, the indoor unit
(3) is an indoor heat exchanger (31) as a heat exchanger on the use side that serves as an evaporator during cooling operation and a condenser during heating operation, and an indoor fan (3F) attached to the indoor heat exchanger (31). Equipped with
On the liquid pipe side of the refrigerant pipe (4) connected to the indoor heat exchanger (31), there is an indoor electric expansion valve (32) that regulates the refrigerant flow rate during heating operation and throttles the refrigerant during cooling operation. It is provided. And the outdoor unit (2) and the indoor unit
(3) is connected by a connecting pipe (41) which is a refrigerant pipe (4), and each device such as the compressor (21), the outdoor heat exchanger (24) and the indoor heat exchanger (31) is a refrigerant. A main refrigerant circuit (11) connected to the closed circuit by the pipe (4) is configured to release the heat obtained by heat exchange with the outdoor air to the indoor air.

Further, (42) is a bypass path for heating overload control that bypasses the outdoor heat exchanger (24), and the bypass path (42) is common to the outdoor heat exchanger (24). Auxiliary heat exchanger (4a) installed in the air passage and capillary tube (4b)
, And an auxiliary opening / closing valve (4c) that opens when the refrigerant is at a high pressure are connected in series and in parallel to the outdoor heat exchanger (24), constantly during cooling operation and excessively high pressure during heating operation. At the same time, the auxiliary opening / closing valve (4c) is turned on and opened,
A part of the discharged gas is bypassed from the main refrigerant circuit (11) to the heating overload control bypass passage (42). The heating overload control bypass passage (42) condenses a part of the discharge gas in the auxiliary heat exchanger (4a) to assist the capacity of the outdoor heat exchanger (24), and also in the capillary tube (4b). It is designed to be balanced with the pressure loss on the outdoor heat exchanger (24) side. (43) is a liquid injection bypass passage for injecting a liquid refrigerant into the suction side of the compressor (21) during heating and cooling operation to adjust the superheat of the suction gas, and the compressor (21)
Injection valve that opens when the discharge pipe temperature rises excessively
(4d) and the capillary tube (4e) are interposed.
(44) is the oil separator via the capillary tube (4f)
An oil return pipe for returning the lubricating oil from (22) to the compressor (21). (45) is a pressure equalizing hot gas bypass passage that connects the discharge-side refrigerant pipe (4) and the suction-side refrigerant pipe (4) of the compressor (21). A pressure equalizing valve (4g) and a capillary tube (4h) that are opened for a certain period of time before stopping and before restarting are installed. (46) is a pressure equalizing passage connected between the receiver (26) and the pressure equalizing hot gas bypass passage (45), one end of which is on the upper end surface of the receiver (26) and the other end of which is equalizing the above. It is connected to the upstream side of the pressure equalizing valve (4g) in the pressure hot gas bypass passage (45). This pressure equalizing path (46)
A check valve (4i) that allows only the refrigerant to flow from the receiver (26) to the pressure equalizing hot gas bypass passage (45) is installed.
With the (4g) open, the gas refrigerant in the upper layer in the receiver (26) equalizes the hot gas bypass passage (45), that is, the suction of the compressor (21) without introducing the liquid refrigerant. It can be installed on the side. Further, (2b) cools the suction refrigerant by heat exchange between the suction refrigerant on the suction side of the compressor (21) and the liquid refrigerant in the liquid pipe of the refrigerant pipe (4), and the refrigerant in the communication pipe (41). Is a suction pipe heat exchanger for compensating for an increase in the degree of superheat.

Further, the air conditioner (1) is provided with many sensors, and (Th1) is a room temperature sensor for detecting an indoor temperature T1 which is the temperature of intake air in the room, (Th2) and (Th3) is the liquid refrigerant temperature T2 and the gas refrigerant temperature in the liquid side and gas side refrigerant pipes (4) of the indoor heat exchanger (31), respectively.
Indoor liquid temperature sensor and indoor gas temperature sensor that detect T3, (T
h4) is a discharge pipe sensor that detects the discharge pipe temperature T4 of the compressor (21), (Th5) is an outdoor liquid temperature sensor that detects defrost etc. from the liquid refrigerant temperature T5 of the outdoor heat exchanger (24), Th6) is a suction pipe sensor that is arranged in the suction refrigerant pipe (4) on the downstream side of the suction pipe heat exchanger (2b) and detects the suction pipe temperature T6 of the compressor (21), and (Th7) is an outdoor The outside air temperature sensor (P1), which is arranged at the air inlet of the heat exchanger (24) and detects the outside air temperature T7 which is the temperature of the intake air outside the room, (P1) is arranged on the discharge side of the compressor (21). A high pressure sensor for detecting the high pressure side pressure of the refrigerant circuit (11),
(P2) is arranged on the suction side of the compressor (21) and is connected to the main refrigerant circuit (1
The low-pressure sensor, which is the low-pressure detection means for detecting the low-pressure side pressure in (1), (HPS) is a compressor installed on the discharge side of the compressor (21).
It is a high-pressure pressure switch for protection of (21). The electric expansion valves (25, 32) and the sensors (Th1 to Th7) are connected to the control unit (5) by a signal line, and the control unit (5) is connected to the sensors (Th1 to Th7). In response to the detection signal of, the opening / closing control of each electric expansion valve (25, 32) and the capacity control of the compressor (21) are performed.

Further, the control unit (15) is provided with an expansion valve control means (51), a start control means (52), an opening adjustment means (53), and an end means (54) as a feature of the present invention. Has been. The expansion valve control means (51) performs PI control (proportional) of the opening degree of the outdoor electric expansion valve (25) so that the refrigerant superheat degree on the outlet side of the outdoor heat exchanger (24) becomes a constant value during heating operation.・
Integral control). The startup control means (52) is a startup opening EV (Ft) obtained by multiplying a preset opening EV (Ft) of the outdoor electric expansion valve (25) by a constant a when the heating operation is started.
The fixed opening EV (F
t) is preset according to the operating frequency of the compressor (21). Further, the opening adjustment means (53) is a low pressure sensor (P
Based on the low pressure side pressure (low pressure refrigerant pressure) detected by 2), when the low pressure side pressure is equal to or higher than a predetermined pressure, the activation control means (52) activates and opens the opening degree of the outdoor electric expansion valve (25). The closing control signal is output so as to be smaller than the pressure, and the start control means is provided as the low-pressure side pressure falls below a predetermined pressure.
(52) outputs an opening signal so as to increase the opening of the outdoor electric expansion valve (25). Specifically, the opening adjustment means
(53) is zero constants a the low-pressure side pressure is at 3 kg / cm ² or more, and the constant a 0.3 low-pressure side pressure is less than 3 kg / cm ² at 2 kg / cm ² or more, low pressure the side pressure is greater than 2 kg / cm ² than 1 kg / cm ² constant a 0.5, activation control means so as to set the low-pressure side pressure is 1 kg / cm ² or less constant a 2 ( It is configured to output a closing motion signal or an opening signal to 52). The termination means (54) is configured to terminate the activation control of the activation control means (52) when a predetermined time has elapsed from the time of activation of the heating operation. The end signal is output after 240 seconds, which is the sum of the software start time of 60 seconds and the control time after the soft start time of 180 seconds, elapses 240 seconds.

Next, the operation of the air conditioner (1) will be described. In Fig. 2, during the cooling operation of the air conditioner (1), the four-way switching valve (23) is switched to the solid line side in the figure, and the auxiliary opening / closing valve (4c) of the auxiliary heat exchanger (4a) is always open,
The refrigerant compressed by the compressor (21) is condensed by the outdoor heat exchanger (24) and the auxiliary heat exchanger (4a), and is sent to the indoor unit (3) via the communication pipe (41). And this indoor unit
In (3), the liquid refrigerant is decompressed by the indoor electric expansion valve (32),
After evaporating in the indoor heat exchanger (31), it returns to the outdoor unit (2) in a gas state through the communication pipe (41) and circulates so as to be sucked into the compressor (21). In other words, the liquid refrigerant is the indoor heat exchanger (3
In 1), the indoor air is cooled by exchanging heat with the indoor air and evaporating. Further, during the heating operation, the four-way switching valve (23) is switched to the side of the broken line in the figure, the flow of the refrigerant is opposite to that during the cooling operation, and the refrigerant compressed by the compressor (21) becomes the indoor heat. After being condensed in the exchanger (31), flowing in the liquid state to the outdoor unit (2), decompressed by the outdoor electric expansion valve (25), and evaporated in the outdoor heat exchanger (24), the compressor (2
Cycle to return to 1). That is, the gas refrigerant heats the indoor air by exchanging heat with the indoor air in the indoor heat exchanger (31) and condensing.

Therefore, the opening control of the outdoor electric expansion valve (25) at the start of the heating operation will be described based on the control flow shown in FIG. First, when the heating operation switch is turned on and the heating operation is started, the compressor (21) is started in step ST1, and for example, the operation frequency of the compressor (21) during normal operation is 60 seconds. Soft start compressor (21) at lower low frequencies. afterwards,
From step ST1 to step ST2, it is determined whether or not the heating operation is performed. If the heating operation is not performed, the determination at step ST2 becomes NO and the operation proceeds to step ST3 to execute the cooling operation module.

On the other hand, in step ST2, if the heating operation is the current state, the determination becomes YES and the process moves to step ST4, and the activation control means (52) is fixedly opened until the soft activation time of 60 seconds elapses. The outdoor electric expansion valve (25) is controlled to the opening degree EV (Ft) · a obtained by multiplying the degree EV (Ft) by the constant a. Further, the opening degree adjusting means (53) receives the detection signal of the low pressure sensor (P2) and determines whether the low pressure side pressure is low. If the low pressure side pressure is 3 kg / cm ² or more, Starting control means (52)
Outputs a closing signal so that the constant a is set to 0. That is, when the low-pressure side pressure is low, the activation control means (52) controls the outdoor electric expansion valve (25) to be fully closed to prevent liquid back. After that, if the pressure on the low pressure side becomes too low and becomes ² kg / cm ² or more and less than 3 kg / cm ² ,
The opening control means (53) outputs an opening signal so that the start control means (52) sets the constant a to 0.3, and the pressure on the low pressure side is reduced to be larger than 1 kg / cm ^2. 2 kg / cm ²
When it becomes less than, the opening adjustment means (53), the start control means
(52) outputs an opening signal so as to set the constant a to 0.5, and when the pressure on the low pressure side further decreases to 1 kg / cm ² or less, the opening adjusting means (53) The start control means outputs the opening signal so that the constant a is set to 2. That is, after the outdoor electric expansion valve (25) is fully closed, the outdoor electric expansion valve (2
When the opening degree of 5) is increased or decreased to 1 kg / cm ² or less, the outdoor electric expansion valve (25) is greatly opened for the low pressure protection of the compressor (21). At that time, since the low-pressure side pressure is low, the liquid bag is small.

Subsequently, when the soft start time elapses, the process moves from step ST4 to step ST5, sets a timer of 180 seconds which is the control time, and moves to step ST6. Then, the outdoor electric expansion valve (25) is controlled as in step ST4 until the timer times out, and the opening degree of the outdoor electric expansion valve (25) is increased or decreased as the low-pressure side pressure decreases or increases. . After that, when the timer expires and the control time of 180 seconds elapses, the end means (54) sends an end signal to the start control means (5
2), end the start control and move to step ST7,
The expansion valve control means (51) controls the outdoor electric expansion valve (25) by PI which is a normal control.

Therefore, according to the present embodiment, the starting opening of the outdoor electric expansion valve (25) at the time of startup is reduced in accordance with the low pressure refrigerant pressure, and for example, the heating operation at low outside air is performed. At the time of startup, even if the liquid refrigerant in the outdoor heat exchanger (24) is difficult to evaporate, it is possible to prevent the refrigerant from becoming too wet at the outlet side of the outdoor heat exchanger (24),
Liquid back can be reliably prevented. Further, since the liquid back can be prevented, the concentration of the lubricating oil in the compressor (21) does not decrease, and it is possible to reliably secure the oil supply to the metal portion of the bearing. Furthermore, since the starting opening of the outdoor electric expansion valve (25) is adjusted, if the low-pressure refrigerant pressure is too low, the opening is increased, so that the protective device does not operate and the retry operation is repeated. It can be surely prevented.

In addition, as a second embodiment according to claim 2, as shown by the one-dot chain line in FIG.
Instead of (54), the controller (5) has a superheat detection means (55).
And a termination means (54a). That is, FIG.
As shown in, an outdoor gas temperature sensor (Th8) that detects the temperature of the refrigerant on the gas side of the outdoor heat exchanger (24) is provided, and the superheat detection means
(55) is the outdoor liquid temperature sensor (Th5) and the outdoor gas temperature sensor (Th
8) and the superheat degree of the refrigerant in the outdoor heat exchanger (24) are detected. The termination means (54a) terminates the activation control of the activation control means (52) when the degree of superheat detected by the degree of superheat detection means (55) reaches a predetermined temperature, for example, 0 ° C. It is configured. Therefore, according to the present embodiment, the outdoor heat exchanger is
Since the start control of the outdoor electric expansion valve (25) is terminated based on the degree of superheat of (24), normal control can be started quickly. Further, as a third embodiment according to claim 3, FIG.
As shown by the alternate long and short dash line, instead of the terminating means (54) in the first embodiment, another terminating means (54b) is provided. That is, an oil temperature sensor (Th9), which is an oil temperature detection means for detecting the lubricating oil temperature in the compressor (21), is provided, and the termination means (54b) is provided with the lubrication temperature detected by the oil temperature sensor (Th9). When the oil temperature reaches a predetermined temperature, for example 0 ° C., the startup control of the startup control means (52) is terminated.

Therefore, according to this embodiment, the start control of the outdoor electric expansion valve (25) is terminated based on the oil temperature in the compressor (21), so that the normal control can be started quickly. Since only the oil temperature is detected, startup control can be performed with a small number of sensors. In addition, claim 4
As a fourth embodiment of the present invention, as shown by the one-dot chain line in FIG. 2, instead of (54) in the end means first embodiment, another end means (54c) is provided. That is, when the superheat degree detected by the superheat degree detection means (55) reaches a predetermined temperature and the lubricating oil temperature detected by the oil temperature sensor (Th9) reaches a predetermined temperature, for example, the termination means (54c) is overheated. When the temperature and the oil temperature both reach 0 ° C., the startup control of the startup control means (52) is terminated. Therefore, according to the present embodiment, the start control of the outdoor electric expansion valve (25) is terminated based on the superheat degree of the outdoor heat exchanger (24) and the oil temperature in the compressor (21), so that the normal control is performed. With a quick start,
The liquid bag can be surely prevented. Further, as a fifth embodiment according to claim 5, as shown by the one-dot chain line in FIG. 2, in place of the end means (54) in the first embodiment, another end means (54d) is provided. It is a thing. That is,
The discharge pipe sensor (Th4) constitutes a discharge pipe temperature detecting means for detecting the discharge pipe temperature of the compressor (21), while the end means (54d) is a discharge pipe sensor detected by the discharge pipe sensor (Th4). When the temperature reaches a predetermined temperature, for example 95 ° C., the startup control of the startup control means (52) is terminated. Therefore, according to the present embodiment, since the start control of the outdoor electric expansion valve (25) is terminated based on the discharge pipe temperature of the compressor (21), it is possible to quickly start the normal control and other Since the discharge pipe sensor (Th4) that can also be used for control can be used, an increase in the number of parts can be prevented.

Although each of the embodiments described the air conditioner having one indoor unit, the present invention may have a plurality of indoor units. Further, the outdoor unit is not limited to one compressor (21) and may be one having two compressors (21).

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a refrigerant circuit diagram showing a refrigerant piping system of the air conditioner.

FIG. 3 is a control flow chart showing an opening degree control of an outdoor electric expansion valve.

[Explanation of symbols]

 1 Air conditioner 2 Outdoor unit 21 Compressor 24 Outdoor heat exchanger (heat source side heat exchanger) 25 Outdoor electric expansion valve 3 Indoor unit 31 Indoor heat exchanger (use side heat exchanger) 5 Controller 51 Expansion valve control means 52 Start control means 53 Opening degree control means 54, 54a to 54d Termination means 55 Superheat detection means Th8 Outdoor gas temperature sensor Th9 Oil temperature sensor (oil temperature detection means)

Claims (5)

[Claims] 1. A compressor (21), a heat source side heat exchanger (24),
An operation control device for an air conditioner in which an expansion valve (25) with adjustable opening and a utilization side heat exchanger (31) are connected in sequence to form a closed circuit main refrigerant circuit (11). , A low pressure detection means (P2) for detecting the low pressure refrigerant pressure on the suction side of the compressor (21), and a start for controlling the opening of the expansion valve (25) to a preset opening when the heating operation is started. When the low pressure refrigerant pressure is equal to or higher than a predetermined pressure based on the low pressure refrigerant pressure detected by the control means (52) and the low pressure detection means (P2), the start control means (52) causes the expansion valve (25) to open. The closing control signal so as to make the degree smaller than the starting opening degree, and the starting control means (52) as the low-pressure refrigerant pressure falls below a predetermined pressure.
The opening control means (53) that outputs an opening signal to increase the opening of the expansion valve (25), and the start control of the start control means (52) when a predetermined time has elapsed from the start of heating operation. And a termination means (54) for terminating the operation control device of the air conditioner. 2. A compressor (21), a heat source side heat exchanger (24),
An operation control device for an air conditioner in which an expansion valve (25) with adjustable opening and a utilization side heat exchanger (31) are connected in sequence to form a closed circuit main refrigerant circuit (11). , A low pressure detection means (P2) for detecting the low pressure refrigerant pressure on the suction side of the compressor (21), and a start for controlling the opening of the expansion valve (25) to a preset opening when the heating operation is started. When the low pressure refrigerant pressure is equal to or higher than a predetermined pressure based on the low pressure refrigerant pressure detected by the control means (52) and the low pressure detection means (P2), the start control means (52) causes the expansion valve (25) to open. The closing control signal so as to make the degree smaller than the starting opening degree, and the starting control means (52) as the low-pressure refrigerant pressure falls below a predetermined pressure.
Is an opening adjustment means (53) that outputs an opening signal to increase the opening of the expansion valve (25), and a superheat degree that detects the degree of superheat of the refrigerant in the heat source side heat exchanger (24) during heating operation. And a termination means (54a) for terminating the activation control of the activation control means (52) when the degree of superheat detected by the superheat detection means (55) reaches a predetermined temperature. An air conditioner operation control device characterized by: 3. A compressor (21), a heat source side heat exchanger (24),
An operation control device for an air conditioner in which an expansion valve (25) with adjustable opening and a utilization side heat exchanger (31) are connected in sequence to form a closed circuit main refrigerant circuit (11). , A low pressure detection means (P2) for detecting the low pressure refrigerant pressure on the suction side of the compressor (21), and a start for controlling the opening of the expansion valve (25) to a preset opening when the heating operation is started. When the low pressure refrigerant pressure is equal to or higher than a predetermined pressure based on the low pressure refrigerant pressure detected by the control means (52) and the low pressure detection means (P2), the start control means (52) causes the expansion valve (25) to open. The closing control signal so as to make the degree smaller than the starting opening degree, and the starting control means (52) as the low-pressure refrigerant pressure falls below a predetermined pressure.
Is an opening adjustment means (53) that outputs an opening signal to increase the opening of the expansion valve (25), and an oil temperature detection means that detects the lubricating oil temperature in the compressor (21).
(Th9) and an end means (54b) for ending the start control of the start control means (52) when the lubricating oil temperature detected by the oil temperature detection means (Th9) reaches a predetermined temperature. A characteristic control device for an air conditioner. 4. A compressor (21), a heat source side heat exchanger (24),
An operation control device for an air conditioner in which an expansion valve (25) with adjustable opening and a utilization side heat exchanger (31) are connected in sequence to form a closed circuit main refrigerant circuit (11). , A low pressure detection means (P2) for detecting the low pressure refrigerant pressure on the suction side of the compressor (21), and a start for controlling the opening of the expansion valve (25) to a preset opening when the heating operation is started. When the low pressure refrigerant pressure is equal to or higher than a predetermined pressure based on the low pressure refrigerant pressure detected by the control means (52) and the low pressure detection means (P2), the start control means (52) causes the expansion valve (25) to open. The closing control signal so as to make the degree smaller than the starting opening degree, and the starting control means (52) as the low-pressure refrigerant pressure falls below a predetermined pressure.
Is an opening adjustment means (53) that outputs an opening signal to increase the opening of the expansion valve (25), and a superheat degree that detects the degree of superheat of the refrigerant in the heat source side heat exchanger (24) during heating operation. Detecting means (55) and oil temperature detecting means for detecting the lubricating oil temperature in the compressor (21)
(Th9), when the superheat degree detected by the superheat degree detection means (55) reaches a predetermined temperature and the lubricating oil temperature detected by the oil temperature detection means (Th9) reaches a predetermined temperature, the start control means ( An operation control device for an air conditioner, comprising: an end means (54C) for ending the startup control of 52). 5. A compressor (21), a heat source side heat exchanger (24),
An operation control device for an air conditioner in which an expansion valve (25) with adjustable opening and a utilization side heat exchanger (31) are connected in sequence to form a closed circuit main refrigerant circuit (11). , A low pressure detection means (P2) for detecting the low pressure refrigerant pressure on the suction side of the compressor (21), and a start for controlling the opening of the expansion valve (25) to a preset opening when the heating operation is started. When the low pressure refrigerant pressure is equal to or higher than a predetermined pressure based on the low pressure refrigerant pressure detected by the control means (52) and the low pressure detection means (P2), the start control means (52) causes the expansion valve (25) to open. The closing control signal so as to make the degree smaller than the starting opening degree, and the starting control means (52) as the low-pressure refrigerant pressure falls below a predetermined pressure.
Opening degree adjusting means (53) that outputs an opening signal to increase the opening degree of the expansion valve (25), and discharge pipe temperature detecting means (Th4) that detects the discharge pipe temperature of the compressor (21). And a termination means (54d) for terminating the startup control of the startup control means (52) when the discharge tube temperature detected by the discharge tube temperature detection means (Th4) reaches a predetermined temperature. Operation control device for air conditioner.