JP3235262B2 - Operation control device for 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 operation control device for an air conditioner, and more particularly to a measure for preventing liquid return after a compressor is stopped.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 2-75862
In the refrigerant circuit of the air conditioner, an auxiliary bypass for overload control and the like is provided between the discharge pipe and the liquid line between the receiver and the outdoor electric expansion valve, and the auxiliary bypass is provided. An auxiliary heat exchanger for assisting the condensing capacity is interposed in the bypass path. For example, by using the auxiliary heat exchanger at the time of overload during the heating operation, the reduction of the indoor load is compensated, or the cooling operation is performed. It is a known technique to assist the capacity of the outdoor heat exchanger therein and to maintain the refrigerant state properly.

[0003]

However, in the case where the auxiliary heat exchanger is interposed in the auxiliary bypass passage as in the above-mentioned conventional one, there are the following problems.

[0004] That is, when the compressor is stopped, the high pressure side and the low pressure side are communicated with each other in the gas line, the pressure is equalized, and the pressure difference is substantially eliminated by the equalization control. However, an intermediate pressure still remains in the liquid line extending from the vicinity of the outlet of the auxiliary heat exchanger to the indoor heat exchanger, and the intermediate pressure is equalized with the discharge pressure of the compressor, which is reduced to a low pressure. , The liquid refrigerant may flow into the discharge side of the compressor.

[0005] When the back-flowed refrigerant flows into the oil dome of the compressor through the oil return passage of the oil separator provided on the discharge side of the compressor, the refrigerant is stopped for a long time and then compressed. When starting the machine, oil forming occurs,
Since the oil pressure does not rise to the pressure required for the operation of the compressor, the oil pressure protection switch may be activated to cause an abnormal stop of the air conditioner or to cause liquid compression.

[0006] Even if there is no liquid return from the auxiliary bypass, the liquid refrigerant may flow backward from the outdoor heat exchanger during the cooling operation and from the indoor heat exchanger during the heating operation. And the possibility of liquid compression.
Furthermore, even if there is not so much liquid return that liquid compression occurs,
Under such conditions that the start and stop of the compressor are frequently repeated, when the liquid refrigerant is gradually accumulated in the compressor or the accumulator, the lubricating oil is diluted with the liquid refrigerant and formed on the sliding portion of the compressor. The thickness of the lubricating oil film becomes thin, which may cause a failure such as burn-in of the compressor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid refrigerant with an outdoor heat exchanger, an indoor heat exchanger, and an auxiliary heat exchanger before a compressor of an air conditioner is stopped. By taking measures to move the liquid refrigerant from the device to the receiver, it is possible to effectively prevent oil forming or liquid compression due to the return of the liquid refrigerant as described above, dilution of the oil due to accumulation of the liquid refrigerant in the compressor, and the like. And to improve the reliability.

[0008]

In order to achieve the above-mentioned object, the present invention provides an outdoor electric expansion valve which opens an outdoor electric expansion valve while operating a compressor before stopping the compressor during a cooling operation. Close the valve and allow the liquid refrigerant to be collected by the receiver.

More specifically, as shown in FIG. 1, the means adopted in the first, third , sixth , and ninth aspects of the present invention include a variable displacement compressor (1), an outdoor heat exchanger (6), and an outdoor electric motor. Expansion valve (8),
It is assumed that the air conditioner includes a refrigerant circuit (14) in which a receiver (9), an indoor electric expansion valve (13), and an indoor heat exchanger (12) are sequentially connected.

[0010] As an operation control device of the air conditioner, a stop command is received, and the indoor electric expansion valve (13) and the outdoor electric expansion valve (8) are closed to control the compressor (1) to stop. When the stop control means (52A) receives a stop command during the cooling operation, the operation of the stop control means (52A) is put on standby for a predetermined time, the compressor (1) is reduced in capacity, and the outdoor electric expansion is performed. A residual operation control means (51A) for controlling the valve (8) to open to a large opening and to close the indoor electric expansion valve (13) is provided.

[0011] Further , means taken by the first and third aspects of the present invention.
Is in addition to the above configuration, as shown by the broken line in FIG.
An auxiliary bypass passage (11e) for bypass-connecting the discharge pipe of the compressor (1) and the liquid line, and an auxiliary bypass passage (11
e), an auxiliary heat exchanger (6c) for assisting the condensing capacity and an opening / closing mechanism (SVS) for opening and closing the auxiliary bypass passage (11e). The residual operation control means (51A) controls the opening and closing mechanism (SVS) of the auxiliary bypass path (11e) for a predetermined time.

[0012] Further , the measures taken by the invention of claim 1 are as follows.
In addition to the above configuration, the outlet side end of the auxiliary bypass path (11e) is connected to the upper part of the receiver (9). Then, as shown by the dotted line in FIG. 1, after the control of the residual operation control means (51A) is completed, the control of the stop control means (52A) is put on standby for a further fixed time, and the outdoor electric expansion valve (8) and The indoor electric expansion valve (13) is closed, and the auxiliary bypass passage (11e) is opened and closed (SVS).
And a standby operation control means (53A) for controlling to stop the compressor (1).

As shown in FIG. 1, the means adopted by the invention of claims 2 , 4 , 7 , and 10 is a variable displacement compressor (1), an outdoor heat exchanger (6), and an outdoor electric expansion valve (8). ), Receiver (9), indoor electric expansion valve (13), and indoor heat exchanger (1).
It is assumed that the air conditioner includes a refrigerant circuit (14) formed by sequentially connecting 2).

As an operation control device of the air conditioner, the outdoor electric expansion valve (8) is closed when the stop command is received, the indoor electric expansion valve (13) is closed to a small opening degree or less, and the compressor (1) Control means (52) for controlling to stop
B), when a stop command is received during the heating operation, the operation of the stop control means (52B) is put on standby for a predetermined time, the capacity of the compressor (1) is reduced, and the outdoor electric expansion valve (8) And a residual operation control means (51B) for controlling to open the indoor electric expansion valve (13).

Means taken by the invention according to claims 2 and 4
Is in addition to the above configuration, as shown by the broken line in FIG.
An auxiliary bypass passage (11e) for bypass-connecting the discharge pipe of the compressor (1) and the liquid line, and an auxiliary bypass passage (11
e), an auxiliary heat exchanger (6c) for assisting the condensing capacity and an opening / closing mechanism (SVS) for opening and closing the auxiliary bypass passage (11e) are provided. further,
The residual operation control means (51B) controls the opening and closing mechanism (SVS) of the auxiliary bypass path (11e) for a predetermined time.

Further , the means taken by the invention of claim 2 is as follows.
In addition to the above configuration, the outlet side end of the auxiliary bypass path (11e) is connected to the upper part of the receiver (9). Then, as shown by the dotted line in FIG. 1, after the control of the residual operation control means (51B) is completed, the control of the stop control means (52B) is put on standby for a further fixed time, and the outdoor electric expansion valve (8) is turned off. Close and use the auxiliary bypass (1)
A standby operation control means (53B) for controlling the opening and closing mechanism (SVS) of 1e) to stop the compressor (1) is provided.

Means taken by the invention according to claims 3 and 4
In addition to the above configuration, as shown in FIG. 6, a liquid-seal prevention circuit (40) that bypasses the opening / closing mechanism (SVS) of the auxiliary bypass path (11e), and a liquid-seal prevention circuit (40) interposed therebetween. And a high-pressure control valve (41) that opens when the pressure on the downstream side of the auxiliary bypass passage (11e) becomes higher than the pressure on the upstream side by a predetermined value or more.

The measures taken by the invention of claim 5 are the above-mentioned claim.
6. In the invention of item 1 or 2 , as shown in FIG. 6, a liquid-seal prevention circuit (40) that bypasses the opening / closing mechanism (SVS) of the auxiliary bypass path (11e), and an intervening part in the liquid-seal prevention circuit (40). And a high-pressure control valve (41) that opens when the pressure on the downstream side of the auxiliary bypass passage (11e) becomes higher than the pressure on the upstream side by a predetermined value or more.

[0019] The measures taken by the invention according to claims 6 and 7 are as follows.
Includes a residual operation control unit (51) in addition to the above configuration ,
When a stop command is received before the first set time elapses after the start of the compressor (1), the residual operation is performed for a long time corresponding to the capacity of the accumulator (10).

The measures taken by the invention of claim 8 are the above-mentioned claim.
In the invention of Item 6 or 7 , as shown by the broken line in FIG. 1, an auxiliary bypass passage (11e) for bypass-connecting the discharge pipe of the compressor (1) and the liquid line, and an auxiliary bypass passage (11e) are provided. An auxiliary heat exchanger (6c) for assisting the condensation capacity and an opening / closing mechanism (SVS) for opening and closing the auxiliary bypass path (11e) are provided. The residual operation control means (51A) controls the opening and closing mechanism (SVS) of the auxiliary bypass path (11e) for a predetermined time.

[0021] The measures taken by the invention according to claims 9 and 10 are as follows.
Includes a residual operation control unit (51) in addition to the above configuration ,
After the start of the compressor (1), the compressor (1) is operated until the second set time elapses from the end of the defrost operation or the oil return operation.
When the stop command is received, the accumulator (10)
The residual operation is to be performed for a long time corresponding to the capacity.

The means taken by the invention of claim 11 is the above-mentioned contractor.
In the invention according to claim 9 or 10 , as shown by a broken line in FIG. 1, an auxiliary bypass path (11e) for bypass-connecting the discharge pipe of the compressor (1) and the liquid line, and the auxiliary bypass path (11e). And an opening / closing mechanism (SVS) for opening and closing the auxiliary heat exchanger (6c) for opening and closing the auxiliary bypass path (11e). The residual operation control means (51A) controls the opening and closing mechanism (SVS) of the auxiliary bypass path (11e) for a predetermined time.

The means taken by the invention of claim 12 is the above-mentioned contractor.
In the invention according to claim 6, 7 or 8 , the residual operation control means (51) is provided after the compressor (1) is started until the second set time elapses from the end of the defrost operation or the oil return operation. When the stop command of (1) is received, the residual operation is performed for a long time corresponding to the capacity of the accumulator (10).

The means taken in the invention of claim 13, the 請
In the invention according to any one of Claims 6 to 12, when the start-up command of the compressor (1) is issued during the residual operation by the residual operation control means (51), control is performed so as to directly shift to the normal operation. Operation transition control means is provided.

The means taken in the invention of claim 14, the 請
In the invention as set forth in claim 13 , when the stop instruction of the compressor (1) is received after the transition to the normal operation by the normal operation transition control means, the continuous operation time of the normal operation before the start of the residual operation and the transition from the residual operation are performed. When the sum of the normal operation and the continuous operation time is longer than the first set time, the operation of the residual operation control means (51) is forcibly stopped and the operation is shifted to the control of the stop control means (52). Avoidance measures (54
A) is provided.

The means taken in the invention of claim 15, the 請
The low-pressure detecting means (LP) for detecting the low-pressure side pressure of the refrigerant circuit (14) according to any one of claims 6 to 14,
The residual operation control means (51) receives the output of the low pressure detecting means (LP) during the residual operation, and sets the closed electric expansion valve (13 or 8) to a low pressure side pressure lower than the lower limit pressure. In some cases, the opening degree is controlled to be a small opening, and when the low pressure side pressure is higher than the lower limit pressure, the opening degree is controlled to be closed.

The means taken in the invention of claim 16, the 請
The invention according to any one of claims 6 to 15, wherein the discharge pipe temperature detecting means (Thd) for detecting the discharge pipe temperature and the discharge pipe temperature detecting means when a stop command is received during operation of the air conditioner. When the discharge pipe temperature detected at (Thd) is equal to or higher than a predetermined temperature, the operation of the residual operation control means (51) is forcibly stopped, and the operation is shifted to the control of the stop control means (52). 54B).

The means taken in the invention of claim 17, the 請
The invention according to any one of claims 6 to 15, wherein the oil temperature detecting means for detecting a temperature of the lubricating oil of the compressor (1); When the temperature of the lubricating oil detected by the detection means is equal to or higher than the predetermined temperature, the operation of the residual operation control means (51) is forcibly stopped, and the operation is shifted to the control of the stop control means (52). 54C).

[0029]

With the above arrangement, according to the first, third , sixth , and ninth aspects of the present invention, a command to stop the compressor (1) is issued during the cooling operation of the air conditioner, at the end of operation of the air conditioner, or at the time of thermo-off. Is performed, the residual operation control means (51A)
The control of the stop control means (52A) is put on standby for a predetermined time, the compressor (1) is operated, and the indoor electric expansion valve (13) is operated.
Is closed and the outdoor electric expansion valve (8) is opened, so that the liquid refrigerant stored in the outdoor heat exchanger (6) is recovered by the receiver (9) during the cooling operation by the so-called pump-down operation. You. Then, in this state, each valve is closed by the stop control means (52A), so that the flow of the liquid refrigerant from the liquid line side to the compressor (1) is stopped while the compressor (1) is stopped.

In the first and third aspects of the present invention, when the residual operation is performed by the residual operation control means (51A), the opening / closing mechanism (SVS) of the auxiliary bypass passage (11e) is opened, so that the auxiliary heat exchanger (6c) is opened. The liquid refrigerant remaining in the compressor (1) is also recovered by the receiver (9), and the liquid return of the compressor (1) is more reliably prevented.

Further, according to the first aspect of the present invention, when the control of the residual operation control means (51A) ends, the pressure in the receiver (9) may increase due to the recovery of the liquid refrigerant to the receiver (9). However, the standby operation control unit (53A) controls the stop control unit (52A) to wait for a certain period of time to open the opening / closing mechanism (SVS) of the auxiliary bypass path (11e). So the receiver (9)
The gas refrigerant flows out to the discharge side via the auxiliary bypass path (11e) connected to the upper part of the compressor, and is equalized with the discharge side of the compressor (1). Therefore, the gas refrigerant is prevented from flowing back together with the noise from the closed valve.

According to the second, fourth , seventh and tenth aspects of the present invention, when a stop command is received during the heating operation, the residual operation control means (5)
1B), the compressor (1) is reduced in capacity for a predetermined time, the outdoor electric expansion valve (8) is closed, and the indoor electric expansion valve (1) is closed.
Since it is controlled to open 3), the liquid refrigerant stored in the indoor heat exchanger (12), which has been a condenser, is recovered by the receiver (9) by the pump-down action. Therefore, even after the stop control means (52B) is controlled to close the outdoor electric expansion valve (8), close the indoor electric expansion valve (13) to a small opening degree or less, and stop the compressor (1). , Compressor (1) from indoor heat exchanger (12) side
Is prevented from returning to the discharge side.

According to the second and fourth aspects of the present invention, during the residual operation of the residual operation control means (51B), the auxiliary bypass path (1
Since the opening and closing mechanism (SVS) of 1e) is opened, the liquid refrigerant of the auxiliary heat exchanger (6c) is recovered by the receiver (9), and the pump-down action can be more reliably obtained. Therefore, the return of the liquid to the compressor (1) is more reliably prevented.

Further, according to the present invention, after the control of the residual operation control means (51B) is completed, the standby operation control means (5) is provided.
3B), the stop control means (52
B), the outdoor electric expansion valve (8) is closed, and the opening and closing mechanism (SV) of the auxiliary bypass passage (11e) is closed.
Since only the S) is opened and the compressor (1) is controlled to stop, even if the gas refrigerant pressure in the receiver (9) increases due to the recovery of the liquid refrigerant, the gas in the receiver (9) is The refrigerant flows out to the discharge side of the compressor (1) and is equalized, so that generation of noise due to the outflow of the gas refrigerant is prevented.

According to the third , fourth , and fifth aspects of the present invention, even if the pressure in the receiver (9) in which a large amount of liquid refrigerant is stored increases due to the residual operation, if the increased pressure value exceeds a predetermined value, The liquid refrigerant gradually flows out to the auxiliary heat exchanger (6c) through the high-pressure control valve (41) of the liquid seal prevention circuit (40) attached to the auxiliary bypass passage (11e), and the equipment is damaged. Is prevented.

[0036] In the invention of claim 6 and 7, during operation of the air conditioner, under conditions such start-stop are repeated frequently compressor (1), the residual operation control means (51),
Before the compressor (1) is stopped, the residual operation with the pump-down action is performed for a long time, so that the liquid refrigerant accumulated in the compressor (1) and the accumulator is almost recovered by the receiver (9). . Therefore, even when the compressor (1) is restarted after being stopped, failure of the compressor due to dilution of oil by the liquid refrigerant or the like is avoided.

In the eighth aspect of the present invention, the opening and closing mechanism (SVS) of the auxiliary bypass passage (11e) is opened during the residual operation of the residual operation control means (51B), so that the auxiliary heat exchanger (6) is opened.
The liquid refrigerant of c) is collected in the receiver (9), and the pump-down action can be obtained more reliably. Therefore, the return of the liquid to the compressor (1) is more reliably prevented.

According to the ninth , tenth , and twelfth aspects of the present invention, the residual operation is performed during the operation of the air conditioner, particularly when not much time has passed since the defrost or oil return operation in which the refrigerant is on the wet side is performed. Since the control unit (51) performs the residual operation for a long time before stopping the compressor (1),
The same operation as that of the above-described claims 6 and 7 can be obtained.

According to the eleventh aspect of the present invention, since the opening and closing mechanism (SVS) of the auxiliary bypass passage (11e) is opened during the residual operation of the residual operation control means (51B), the auxiliary heat exchanger (6) is opened.
The liquid refrigerant of c) is collected in the receiver (9), and the pump-down action can be obtained more reliably. Therefore, the return of the liquid to the compressor (1) is more reliably prevented.

According to the thirteenth aspect of the present invention, the normal operation shift control means shifts from the residual operation to the normal operation.
The refrigerant does not flow backward due to the stop of the compressor (1). Therefore, the reliability of the compressor (1) is maintained without deterioration of the comfort of the air conditioning as in the case where the compressor (1) is stopped and then restarted by performing the residual operation as it is.

According to a fourteenth aspect of the present invention, in the operation of the thirteenth aspect , when a stop command is issued during the normal operation directly shifted from the residual operation, the first set time is set after the shift to the normal operation. Even if the above time has not elapsed, if the sum of the normal operation time before the residual operation and the normal operation time after the residual operation exceeds the first set time, the accumulation of the liquid refrigerant is not so large. Absent. Therefore, the remaining operation avoiding means (54A) avoids the entry into the residual operation under such conditions, thereby avoiding the deterioration of the comfort of the air conditioning due to the extra residual operation.

According to the fifteenth aspect , during the residual operation, the low pressure side pressure is maintained at or above the lower limit pressure by opening / closing control of the electric expansion valve (8 or 13), so that the residual operation for a long time is secured. . Therefore, the liquid refrigerant such as the accumulator (10) is sufficiently discharged, and the danger of oil dilution or the like is avoided.

According to the sixteenth aspect of the present invention, when the discharge pipe temperature is equal to or higher than the predetermined temperature, the refrigerant is not wet but dry, and the accumulation of the liquid refrigerant in the compressor (1) or the like is small. Even without performing the above, there is almost no fear of oil dilution or the like. Therefore, the residual operation avoidance means (5
According to 4B), under such a condition, the entry into the residual operation is avoided, so that the deterioration of the comfort of the air conditioning due to the extra residual operation is avoided.

According to the seventeenth aspect , when the oil temperature is high, the accumulation of the liquid refrigerant in the compressor (1) and the like is small, and there is almost no danger of oil dilution or the like without performing the residual operation. become. Therefore, the remaining operation avoiding means (54B) prevents entry into the residual operation under such conditions, thereby avoiding deterioration of the comfort of air conditioning due to extra residual operation.

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

First, a first embodiment of the present invention will be described. FIG. 2 shows a refrigerant piping system of the multi-type air conditioner according to the first embodiment of the present invention, wherein (X) is an outdoor unit,
(Y1), (Y2),... Are indoor units connected in parallel to the outdoor unit (X). Inside the outdoor unit (X), two three-way switching valves (SV1), (SV1)
The operation capacity is 100%, 67%, 3
A compressor (1) adjusted to three stages of 3%, and a first (1) for separating oil in a gas refrigerant discharged from the compressor (1).
A second oil separator (4a), (4b), a four-way switching valve (5) that switches during cooling operation as shown by a solid line in the figure and that switches during heating operation as shown by a broken line in the figure, and a condenser and heating during cooling operation A pair of outdoor heat exchangers (6a) serving as evaporators during operation,
(6b) and two outdoor fans (F1) and (F2) attached to the outdoor heat exchangers (6a) and (6b). Each of the above outdoor heat exchangers (6a) and (6b)
It is arranged in parallel in the circuit, and each outdoor heat exchanger (6
Contrary to (a) and (6b), a pair of outdoor electric expansion valves (8a1), (8a2) and (8b1), (8b2) for adjusting the flow rate of the refrigerant during the cooling operation and performing the throttling operation of the refrigerant during the heating operation.
Are arranged. Further, the outdoor unit (X) is provided with a receiver (9) for storing a liquefied refrigerant and a pair of first and second accumulators (10a) and (10b). The devices (1) to (10b) are sequentially connected by a refrigerant pipe (11) so that the refrigerant can flow. The indoor units (Y1), (Y2),... Have the same configuration, and include an indoor heat exchanger (12) and a fan (12a), which serve as an evaporator during a cooling operation and a condenser during a heating operation, respectively. An indoor electric expansion valve (1) that adjusts the refrigerant flow rate during operation and performs a throttle function of the refrigerant during cooling operation.
3) are arranged respectively, and after merging, the liquid side manual shutoff valve (1)
7) and the outdoor unit (X) are connected by a liquid side communication pipe (11a) and a gas side communication pipe (11b) via a gas side manual shutoff valve (18). That is, a main refrigerant circuit (14) is connected to each of the above devices by a refrigerant pipe (11) so as to allow a refrigerant to flow therethrough, and discharges heat obtained by heat exchange with outdoor air to indoor air. It is configured.

Next, auxiliary devices other than the above main devices are provided. An equalizing hot gas bypass passage (11d) is provided between the discharge pipe and the suction pipe to equalize the high pressure side and the low pressure side pressure when the compressor (1) is stopped. In the equalizing hot gas bypass passage (11d),
When the compressor (1) is stopped due to a thermo-off state or the like, a pressure equalizing on-off valve (SVP) that opens for a predetermined time before restarting is provided. Further, the first and second oil separators (4a),
An oil return pipe (33) for returning oil through a capillary tube (32) is provided from (4b) to the rising pipe at the outlet of the second accumulator (10b).

Further, the oil separators (4a) and (4b)
A heating overload control circuit (11e) for connecting the discharge pipe between the four-way switching valve (5) and the upper part of the receiver (9), wherein the heating overload control circuit (11e) includes a discharge pipe; In order from the side, the auxiliary heat exchanger (6c) and the capillary tube
(23) and an overload control on-off valve (S
VS). The heating overload control circuit (11e) is provided with a liquid seal prevention circuit (40) that bypasses the overload control valve (SVS). The pressure is the auxiliary heat exchanger (6
A high-pressure control valve (41) that opens only when the pressure becomes higher than the pressure on the side c) by a predetermined value or more and allows the refrigerant to flow is interposed.

The outdoor electric expansion valve (8a1) for the liquid line
A liquid injection bypass passage (11f) for bypass-connecting a part between (8b2) -receiver (9) and a suction pipe upstream of the first accumulator (10a) is provided, and the bypass passage (11f) is provided in the bypass passage (11f). Is an injection on-off valve (S) that opens and closes to regulate overheating of the suction refrigerant.
VL).

Note that (GP) is a gage port.

Further, a large number of sensors are arranged in the apparatus, and (Th1a) and (Th1b) are the outdoor heat exchangers (6a) and (Th1b).
(6b) a gas pipe sensor for detecting the gas pipe temperature, (Th2
a) and (Th2b) are liquid tube sensors for detecting liquid tube temperatures of the outdoor heat exchangers (6a) and (6b), and (Thd) is a discharge tube temperature for detecting a discharge tube temperature Td of the compressor (1). A discharge pipe sensor as a detection means, (Thr) is disposed at an air suction port of each indoor unit (Y1) and detects an intake air temperature (room temperature), and (LP) is a suction pressure (low pressure side pressure). ) T
e, a low-pressure sensor as a low-pressure detecting means for detecting e.
QL) is a differential pressure sensor that detects the pressure difference between oil pressure and suction pressure, (HP) is a high pressure sensor that detects discharge pressure (high pressure side pressure), and (63H) is a high pressure switch that protects the compressor. The signals from these sensors can be input to a controller (not shown) of the air conditioner.

In FIG. 2, during the cooling operation of the air conditioner, the four-way switching valve (5) is switched to the solid line side in the figure, and the refrigerant compressed by the compressor (1) is supplied to each outdoor heat exchanger (6a). ,
After being condensed in (6b) and stored in the receiver (9),
Through the liquid side connection pipe (11a), each indoor unit (Y
1), (Y2),... In each of the indoor units (Y1), (Y2),..., The refrigerant is decompressed by each of the indoor electric expansion valves (13), evaporated in each of the indoor heat exchangers (12), and then joined to form a gas-side communication pipe (11b). ), Return to the outdoor unit (X), and accumulators (10a),
After the mixed liquid refrigerant is removed in (10b), the refrigerant is circulated so as to be sucked into the compressor (1).

During the heating operation, the four-way switching valve (5)
Is switched to the broken line side in the figure, and the flow of the refrigerant is opposite to that in the cooling operation, and the refrigerant compressed in the compressor (1) is condensed in the indoor heat exchangers (12), (12),. Then, they merge and flow in a liquid state to the outdoor unit (X), and are stored in the receiver (9). Then, each of the outdoor electric expansion valves (8a1) to (8
The pressure is reduced by b2) and each outdoor heat exchanger (6a), (6
After evaporating in b), it circulates back to the compressor (1).

Next, regarding the electric circuit of the air conditioner,
This will be described with reference to FIG. In FIG. 3, an external device circuit (100) is connected to a three-phase AC power supply (TeS), and a main device drive board (110) and a valve drive And a connection substrate (120). Further, a control substrate (130) is connected to the main device driving substrate (110) via a first transformer (Tr1).

In the external device circuit (100),
(MC) is a compressor motor for driving the compressor (1), (MF1) and (MF2) are fan motors for driving two outdoor fans (F1) and (F2), respectively. The compressor motor (MC) has a normally open contact (52C-1) of an electromagnetic relay (52C) for starting and stopping described later and a fuse (52C) for opening an overcurrent protection switch (51C) described later. 51C-f) are connected in series, and the normally open contacts (42C-1) and (6C-1) of the electromagnetic relays (42C) and (6C) for startup control are additionally provided. Each fan motor (MF1) and (MF2) has a normally open contact (52F1--F) for starting and stopping electromagnetic relays (52F1) and (52F2) described later.
1), (52F2-1) and overcurrent protection switch (51F1), (51F1)
Fuse (51F1-f) for opening operation of F2), (51F2
-f) are connected in series.

The main device driving board (110) includes a high voltage protection switch (63H), an overcurrent protection switch (51C) for the compressor (1), and a temperature rise protection switch (49C) for the compressor (1). ) And fan overcurrent protection switch (51F
Protection circuit (111) including (1) and (51F2)
And normally open relay contacts (RY2), (RY4), (RY
6), (RY7) and (RY8), the fan drive electromagnetic relays (52F1) and (52F2), the compressor drive electromagnetic relay (52C) and the compressor start control electromagnetic relay (42
C) and (6C), a first actuator drive circuit (112), and normally open relay contacts ((RY9) to (RY9) to
(RY15), an electromagnetic relay (WL) for abnormality indication, an electromagnetic relay (20S) for switching the four-way switching valve (2), and a three-way switching valve (SV) for the unloader.
1), electromagnetic relay (20RS1) for switching (SV2),
(20RS2), an electromagnetic relay (20R1) for opening and closing the equalizing on-off valve (SVP), an electromagnetic relay (20R2) for opening and closing the overload control on-off valve (SVS), and the injection on-off valve (SVL) And a second actuator drive circuit (113) provided with an electromagnetic relay (20R3) for opening and closing the actuator.

(CH) is a crankcase heater,
(52C-2) is a normally open contact of the compressor driving electromagnetic relay (52C), which turns on the crankcase heater (CH). The transistor which is turned off, (Q1) is a power transistor for generating power.

On the other hand, the valve driving substrate (120) includes:
Pulse motors (20E1) to (20E4) of four outdoor electric expansion valves (8a1) to (8b2) are arranged via the second transformer (Tr2).

Further, the control board (130) includes:
Service mode changeover switch (DS1), compressor forced operation or oil pressure protection reset setting switch (SS1), low noise input changeover switch (SS2), cooling / heating changeover switch (SS3),
Pipe length setting switch (SS4), high pressure adjustment switch (SS
5), a defrost changeover switch (SS6) and a compressor forced operation button switch or a hydraulic pressure protection reset button switch (BS1) are provided, and the differential pressure sensor for pressure (63QL), each gas pipe sensor (Th1a), (Th1b),
Discharge pipe sensor (Thd), each liquid pipe sensor (Th2b), (Th2
b), a high pressure sensor (HP) and a low pressure sensor (LP) are connected via a signal line.

Next, the contents of the control during the cooling operation of the air conditioner will be described.

First, in step ST1, normal cooling operation is performed, during which the outdoor fans ((F1) and (F2) are operated, and the outdoor electric expansion valves (8a1) to (8b2) are fully opened (200).
At 0 pulse), the indoor electric expansion valve (13) is set to the control opening by the superheat constant control, and the compressor (1) is operated. When the stop command is output according to the operation state such as the operation of the air conditioner is completed or all the indoor units (Y1), (Y2),... Are turned off, the determination in step ST2 becomes YES. At the same time, the process proceeds to step ST3.

In step ST3, a residual pump down operation is performed as follows. At this time, the outdoor fan (F
1) and (F2) are operated to set the capacity of the compressor (1) to a minimum step of 33%, and the outdoor electric expansion valves (8a1) to (8b2)
Are fully opened, the indoor electric expansion valves (13),... Are fully closed, and the overload control valve (SVS) of the heating overload control circuit (11e) is controlled to open. And step S
At T4, the residual pump down operation is performed until one minute elapses, and when one minute elapses, the process proceeds to step ST5. That is, the liquid refrigerant stored in the outdoor heat exchangers (6a) and (6b) and the auxiliary heat exchanger (6c) is almost recovered to the receiver (9).

In step ST5, the standby operation is controlled as follows. That is, the outdoor fans (F1), (F
2) to stop the compressor (1),
The indoor electric expansion valve (13), ... and the outdoor electric expansion valve (8a
1) to (8b2) are controlled to be fully closed while only the overload control valve (SVS) of the heating overload control circuit (11e) is opened. Then, in step ST6, it is determined whether or not three minutes have elapsed. When three minutes have elapsed, the process proceeds to step ST7. That is, the refrigerant pressure in the receiver (9) is prevented from rising, and the gas refrigerant is prevented from flowing back together with the sound.

Further, at step ST7, the overload control valve (SVS) of the heating overload control circuit (11e) is closed, and the other devices perform stop control for controlling the other devices in the standby operation control state.

Under the control of steps ST3 and ST4,
The residual operation control means (51A) is constituted, and step ST
The control of 7 constitutes a stop control means (52A).

The control of opening the overload control valve (SVS) during the control of steps ST3 and ST4 constitutes the function of the residual operation control means (51A).

Further, the standby operation control means (53A) is constituted by the control in steps ST5 and ST6.

Therefore, in the control during the cooling operation of the first embodiment, during the cooling operation of the air conditioner, at the end of the operation of the air conditioner, and at the indoor units (Y1), (Y2),.
When a stop command for the compressor (1) is issued, for example, when the thermostat is turned off, the residual operation control means (52) is closed before the stop control means (52A) closes each valve to stop the compressor (1). 51A), a predetermined time (1 in the above embodiment)
), The capacity of the compressor (1) is set to the minimum capacity of 33%, the indoor electric expansion valves (13), ... are closed, the outdoor electric expansion valves (8a1) to (8b2) are fully opened, and the residual pump is opened. Down operation is performed. In other words, during the cooling operation, the liquid refrigerant is considerably stored in the outdoor heat exchangers (6a) and (6b). In this state, when the compressor (1) is stopped and each valve is closed, The liquid refrigerant remaining in the outdoor heat exchangers (6a) and (6b) is compressed by the differential pressure between the liquid line at the intermediate pressure and the discharge side of the compressor (1) at the equalized pressure. Flows into the discharge side of the machine (1), the oil separator (4a),
Compressor (1) from (4b) via oil return passage (33)
And the hydraulic pressure does not reach a predetermined value required for the operation of the compressor (1), which may cause an abnormal stop or liquid compression due to the operation of the differential pressure sensor (63QL).

On the other hand, in the control of the cooling operation in the above embodiment, the residual pump down operation is performed by the residual operation control means (51A), and the outdoor heat exchanger (6a),
The liquid refrigerant of (6b) is collected in the receiver (9), and in this state, each valve is closed by the stop control means (52A). The backflow of the liquid refrigerant to the discharge side in (1) is prevented. Therefore, the above-described abnormal stop, liquid compression, and the like can be effectively prevented.

In the air conditioner having the heating overload control circuit (11e), the residual operation control means (51)
By opening the overload control valve (SVS) during the residual pump down operation according to A), the liquid refrigerant remaining in the auxiliary heat exchanger (6c) can also be recovered in the receiver (9), The liquid return of the compressor (1) can be more reliably prevented.

In particular, after the control of the residual operation control means (51A) is completed, the control of the stop control means (52A) is further controlled by the standby operation control means (53A) for a certain period of time (3 minutes in the above embodiment). By waiting, and by opening the overload control valve (SVS) of the heating overload control circuit (11e) during that time,
Even if the pressure in the receiver (9) increases due to the residual pump-down operation, a large amount of gas refrigerant is allowed to escape to the discharge side during standby control, and pressure equalization is achieved. Therefore, there is an advantage that the gas refrigerant can be prevented from flowing back together with the loud noise from the closed valve.

Further, as in the first embodiment, the heating overload control circuit (11e) is provided with a liquid-seal prevention circuit (40) and a high-pressure control valve (41) is interposed between the heating overload control circuit (11e) and a large amount of liquid refrigerant. Even if the pressure in the receiver (9) where
There is an advantage that the refrigerant gradually escapes to the auxiliary heat exchanger (6c) side, and damage to devices such as the receiver (9) can be prevented.

Next, control during the heating operation in the first embodiment will be described.

FIG. 5 shows the contents of the control during the heating operation. In step SR1, while the heating operation is being performed, if a stop command is issued in step SR2, a step SR1 is issued.
3, the outdoor fans (F1) and (F2) are operated, the capacity of the compressor (1) is reduced to a minimum capacity of 33%, and the outdoor electric expansion valves (8a1) to (8b2) are fully closed. The indoor electric expansion valves (13),... Are opened to a small opening (200 pulses), and the overload control valve (S) of the heating overload control circuit (11e) is opened.
VS), and the liquid refrigerant remaining in each of the indoor heat exchangers (12),... And the auxiliary heat exchanger (6c) is released to the receiver (9).

Next, when one minute has elapsed in step SR4, the process proceeds to step SR5, where the outdoor fan (F1),
(F2) and the operation of the compressor (1) are stopped, the outdoor electric expansion valves (8a1) to (8b2) are fully closed, and the indoor electric expansion valves (13),. At the same time, the overload control valve (SVS) of the heating overload control circuit (11e) is opened to allow the gas refrigerant to flow out from the upper portion of the receiver (9).

Then, after waiting for 3 minutes in step SR6, the process proceeds to step SR7, where the outdoor fan (F
1), (F2) and the operation of the compressor (1) are stopped, the outdoor electric expansion valves (8a1) to (8b2) are fully closed, and the indoor electric expansion valves (13),. Until the overload control valve (SVS) of the heating overload control circuit (11e) is closed,
Stop.

In the above flow, the residual operation control means (51B) is constituted by the control of steps SR3 and SR4, and the stop control means (5) is controlled by the control of step SR4.
2B).

Further, the overload control valve (S
The control of the residual operation control means (51B) is constituted by the control for opening VS).

Further, the standby operation control means (53B) is constituted by the control of steps SR5 and SR6.

Therefore, in the control during the heating operation in the above embodiment, when the stop command is received, the residual operation control means (5)
1B), the compressor (1) is reduced in capacity (33% in the above embodiment) for a predetermined time (1 minute in the above embodiment).
Are controlled so that the outdoor electric expansion valves (8a1) to (8b2) are closed and the indoor electric expansion valves (13),... Are opened (200 pulses in the above embodiment). The liquid refrigerant stored in the indoor heat exchangers (12),... Is recovered by the receiver (9). Therefore, thereafter, the outdoor electric expansion valves (8a1) to (8b2) are closed by the stop control means (52B), and the indoor electric expansion valve (1) is closed.
3) are closed to a small opening or less and the compressor (1) is stopped so that the liquid refrigerant flows from the indoor heat exchangers (12), ... to the discharge side of the compressor (1). Without going back,
Therefore, abnormal stop and liquid compression due to the operation of the hydraulic differential pressure sensor (63QL) can be effectively prevented.

In the above embodiment, the indoor electric expansion valves (13),.
(0 pulse), but the present invention is not limited to this embodiment, and each indoor electric expansion valve (1
3),... May be fully opened. In this case, the operation of recovering the liquid refrigerant becomes more remarkable when opened to a large opening, but if the indoor electric expansion valves (13),. Since the gas side communication pipe (11b) has a large diameter, even if a small amount of liquid refrigerant flows backward through the gas side communication pipe (11b) after the compressor (1) is stopped, it is sufficient in the communication pipe (11b). It can be absorbed and liquid return of the compressor (1) does not pose a problem.

In the apparatus provided with the heating overload control circuit (11e) and the auxiliary heat exchanger (6c), the overload control valve (SVS) is used during the residual pump down operation of the residual operation control means (51B). , The liquid refrigerant in the auxiliary heat exchanger (6c) can be recovered by the receiver (9), and the effect of preventing abnormal stop, liquid compression, and the like is increased.

Further, after the end of the control of the residual operation control means (51B), the standby operation control means (53B) controls the stop control means (52B) for a further fixed time (3 minutes in the above embodiment). Wait for the outdoor electric expansion valve (8a
1) to (8b2) are closed, and only the overload control valve (SVS) of the heating overload control circuit (11e) is opened to control the compressor (1) to stop. Even when the pressure of the gas refrigerant in the receiver (9) rises, the gas refrigerant in the receiver (9) flows out to the discharge side of the compressor (1) to equalize the pressure without causing noise. Can be planned.

In the stop control means (52B) and the standby control means (53B) in the above-described embodiment, the indoor electric expansion valves (13),... Are opened to a minute opening. The indoor electric expansion valves (13),... May be closed.

Next, a second embodiment will be described. FIG.
Represents a refrigerant piping system of the air conditioner in the second embodiment. As a feature of the present invention, the liquid line side of the liquid injection bypass passage (11f) is connected to a portion of the heating overload control circuit (11e) between the overload control on-off valve (SVS) and the receiver (9). I have. Other configurations are the same as in the first embodiment.

In this case, the residual operation control means (5
During the residual pump down operation control of 1A), the injection on-off valve (SVL) is opened so that the gas refrigerant above the receiver (9) is sucked into the accumulator (10) side.

Therefore, in the second embodiment, by opening the injection on-off valve (SVL), the gas refrigerant above the receiver (9) is sucked into the suction side, and the gas pressure in the receiver (9) decreases. In addition, the flow of the liquid refrigerant into the receiver (9) is facilitated, and sufficient liquid refrigerant can be collected even with a short residual pump-down operation.

That is, when the compressor (1) is stopped and the gas pressure of the receiver (9) rises due to the refrigerant recovery during the cooling operation particularly when the outside air temperature is low, the high pressure of the refrigerant circuit (14) is increased. An excessive rise in the side pressure may cause an abnormal stop (high-pressure cut) of the device due to the operation of the high-pressure protection switch (63H). However, when the gas pressure in the receiver (9) decreases, the high-pressure cut may occur. Thus, the residual pump down operation can be performed without inducing.

In each of the above embodiments, an air conditioner having a plurality of indoor units (Y1), (Y2),... Has been taken as an example. However, the present invention is not limited to such an embodiment. For example, the present invention is also applicable to an arrangement in which a single indoor heat exchanger is arranged in a single indoor unit.

The present invention is also applicable to a compressor (1) in which the capacity is frequency-controlled by an inverter.

Next, a third embodiment of the present invention will be described.

The flowchart of FIG. 7 shows the control contents during the heating operation according to the third embodiment. When a stop command is issued by a thermo-off or a command from a remote control device, at step SP1, the discharge pipe is turned on. It is determined whether or not the discharge pipe temperature Td detected by the sensor (Thd) is lower than a predetermined temperature of 95 ° C., and if Td <95 ° C., the process proceeds to step SP2, where the outside air temperature To is reduced to the predetermined temperature −5. It is determined whether or not the temperature is equal to or lower than 0 ° C., and if To ≦ −5 ° C., the process proceeds to step SP3, and determines whether or not the operation of the compressor (1) is within the first set time (10 minutes). If it is within 10 minutes from the start of the operation of the compressor (1), the process proceeds to step SP6, where a long time (here, 10 minutes) set as a time sufficient to discharge the liquid refrigerant in the accumulator (10) is used. )
During this period, a residual pump down operation substantially similar to that of the first embodiment is performed (see step SR3 in FIG. 5). On the other hand, in the determination in step SP3, one cycle from the start of operation of the compressor (1)
If 0 minute has elapsed, the process further proceeds to step SP4
Then, it is determined whether or not it is within 20 minutes from the end of the defrost or oil recovery operation.
To perform the residual pump down operation.

When the residual pump down operation in step SP5 is completed, when Td ≧ 95 ° C. in the determination in step SP1, or when the defrost or oil recovery operation is within 20 minutes in the determination in step SP4, Proceeding to step SP6, the compressor (1) is stopped.

The control that proceeds from step SP3 to step SP5 constitutes a residual operation control means (51).
That is, under the condition that the start / stop of the compressor (1) is frequently repeated, the compressor (1) and the accumulator (1)
0), the oil in the compressor (1) is diluted by the liquid refrigerant, which may cause a failure of the compressor (1) due to poor lubrication. ), The compressor (1) is stopped after the residual pump-down operation is performed, whereby the liquid refrigerant stored in the accumulator (10) can be almost completely recovered in the receiver (9), as described above. Troubles can be eliminated.

The control that proceeds from step SP4 to step SP5 constitutes a residual operation control means (51). That is, in the defrost operation and the oil recovery operation, the state of the gas refrigerant is slightly wet in order to increase the refrigerant circulation amount, so that the liquid refrigerant amount of the compressor (1) and the like is increasing. Therefore, by stopping the compressor (1) after performing the residual pump-down operation, it is possible to effectively eliminate the risk of oil dilution as described above.

Further, during the residual pump-down operation in step SP5, if there is a command to restart the compressor (1) due to thermo-on or the like, the compressor (1) is shifted to the normal heating operation without stopping it. I am trying to do it. This control constitutes a normal operation transition control unit. With this control, the comfort of the air conditioning is maintained by immediately performing the normal operation while maintaining the reliability without causing the liquid refrigerant to flow backward due to the stop processing of the compressor (1). Can be.

When a stop command is issued after returning to the normal operation by the normal operation transition control means, the continuous operation time of the compressor (1) before the start of the residual pump down operation before the normal operation is determined. Comparing with the continuous operation time of the compressor after returning to operation, if the sum of both operation times is longer than the first set time (10 minutes), the compressor ( The process shifts to the stop control of 1). This control constitutes a residual operation avoiding means (54A) (not shown). That is, under such conditions, the compressor (1)
The state of the refrigerant is the same as when the first set time (10 minutes) has elapsed after the start of, and even if the compressor (1) is stopped as it is, there is little possibility that the amount of the liquid refrigerant will increase. Therefore,
By avoiding an excessively long residual pump-down operation, it is possible to avoid deterioration in air conditioning comfort.

Here, during the residual pump down operation and at the start of the residual pump down operation, the outdoor electric expansion valve (8) is closed and the indoor electric expansion valve (8) is closed, as in step SR3 of FIG. 5 in the first embodiment. 13) is a minute opening 20
During this period, the low pressure side Te detected by the low pressure sensor (LP) is compared with a lower limit pressure (−15.1 to −19.4 ° C. at a saturation temperature corresponding to the evaporating pressure). When Te falls below the lower limit pressure (−19.4 ° C.), the outdoor electric expansion valve (8) is opened by 200 pulses, and when the low pressure side pressure Te returns to the lower limit pressure (−15.1 ° C.) or more, the outdoor electric expansion valve (8) opens. 8) is closed and this opening control is repeated for 10 minutes. By this control, the residual operation control means (5
The function of 1) is configured. That is, during the residual pump-down operation, if the amount of refrigerant in the suction line decreases and the low-pressure side pressure drops excessively, the compressor (1) by low-pressure cut or the like will not be able to sufficiently discharge the liquid refrigerant such as the accumulator (10). ), The residual pump-down operation for a long time (10 minutes) cannot be continued as it is. But,
By performing the open / close control of the outdoor electric expansion valve (8),
Long-term residual pump down operation can be ensured. Therefore, the liquid refrigerant such as the accumulator (10) can be sufficiently discharged, and the possibility of oil dilution or the like can be effectively prevented.

In the third embodiment, when the low-pressure side pressure Te further drops below −25.5 ° C., the equalizing on-off valve (SVP) of the equalizing hot gas bypass passage (11d) is opened, and the low-pressure side When the pressure Te recovers to −19.4 ° C. or higher, the compressor (1) is further protected by controlling to close the equalizing on-off valve (SVP).

The control for shifting from step SP1 to SP6 constitutes a residual operation avoiding means (54B). That is, the discharge pipe temperature Td is set to the predetermined temperature 95
When the temperature is higher than 0 ° C., the refrigerant is not wet but dry, and the accumulation of the liquid refrigerant in the compressor (1) or the like is small.
Even if the residual operation is not performed, there is almost no danger of oil dilution or the like. Therefore, the residual operation avoiding means (54
According to B), it is possible to avoid the entry into the residual operation under such conditions, thereby avoiding the deterioration of the comfort of the air conditioning due to the extra residual pump down operation.

Further, instead of the control in step SP1, the process proceeds to step SP2 or SP6 depending on whether or not the oil temperature in the dome of the compressor (1) is lower than a predetermined temperature (for example, -10 ° C.). Control may be performed. This control constitutes a residual operation avoiding means (54C). That is, when the oil temperature is high, the refrigerant is in a dry state, as in the case where the discharge pipe temperature Td is high. Therefore, by avoiding such residual operation, the same effect as described above can be exerted.

[0102]

As described above, claims 1 and 3
According to the invention of the sixth and ninth aspects , when the stop command is received during the cooling operation of the air conditioner, the indoor electric expansion valve is closed and the outdoor electric expansion valve is opened for a predetermined time while the compressor is operated at a low capacity. After performing the residual operation, the compressor is stopped, and the stop control for closing the outdoor electric expansion valve and the indoor electric expansion valve is performed, so that the liquid refrigerant stored in the outdoor heat exchanger during the cooling operation is received by the receiver. When the compressor is stopped, the compressor is stopped and each valve is closed, so that the flow of the liquid refrigerant from the liquid line side to the compressor during the stop of the compressor can be prevented. Abnormal stop of the air conditioner, liquid compression, and the like can be effectively prevented.

According to the first and third aspects of the present invention, the auxiliary bypass is provided between the discharge pipe and the liquid line via the auxiliary heat exchanger and the opening / closing mechanism. Since the opening and closing mechanism is opened, the liquid refrigerant remaining in the auxiliary heat exchanger is recovered in the receiver, so that the liquid can be more reliably prevented from returning to the compressor.

Further, according to the first aspect of the invention, the outlet side end of the auxiliary bypass is connected to the upper portion of the receiver, and after the residual operation is completed, before the stop control is performed, the outdoor electric expansion is further performed for a certain period of time. Since the valve is closed and the standby control for stopping the compressor by opening only the opening / closing mechanism of the auxiliary bypass is performed, the gas refrigerant is transferred to the discharge side of the compressor via the auxiliary bypass connected to the upper part of the receiver. By causing the gas refrigerant to flow out and equalize the pressure with the discharge side of the compressor, it is possible to prevent the gas refrigerant from flowing back together with the loud noise from the closed valve.

According to the invention of claims 2 , 4 , 7 , and 10 ,
When a stop command is received during the heating operation of the air conditioner, after performing a residual operation of controlling to close the outdoor electric expansion valve and open the indoor electric expansion valve while operating the compressor at a low capacity,
Since the compressor is stopped, the outdoor electric expansion valve is closed, and the indoor electric expansion valve is controlled to stop at a small opening or less, the liquid refrigerant stored in the indoor heat exchanger before the compressor is stopped is removed. The liquid collected by the receiver can be effectively prevented from returning to the compressor.

According to the second and fourth aspects of the present invention, an auxiliary bypass is provided for bypass-connecting the discharge pipe of the compressor and the liquid line via the auxiliary heat exchanger and the opening / closing mechanism. Since the opening / closing mechanism of the bypass passage is opened, the liquid refrigerant of the auxiliary heat exchanger is recovered to the receiver during the residual operation, so that the liquid can be effectively prevented from returning to the compressor. It is possible to prevent abnormal stop of the device, liquid compression, and the like.

Further, according to the second aspect of the present invention, after the residual operation is completed and before the stop control, the outdoor electric expansion valve is closed for a predetermined time and only the opening and closing mechanism of the auxiliary bypass is opened to start the compressor. Since the standby control to stop is performed, even when the gas refrigerant pressure in the receiver increases due to the recovery of the liquid refrigerant during the residual operation, the gas refrigerant in the receiver flows out to the discharge side of the compressor to equalize the pressure. By doing so, it is possible to prevent the gas refrigerant from flowing backward together with loud noise from the closed valve.

According to the third , fourth and fifth aspects of the present invention, a liquid-seal prevention circuit is provided for bypassing the opening / closing mechanism of the auxiliary bypass passage. Since the high pressure control valve which opens when the pressure becomes higher than the predetermined value is provided through the high pressure control valve of the liquid ring prevention circuit even if the pressure in the receiver in which a large amount of liquid refrigerant is stored due to the residual operation increases. By gradually flowing the liquid refrigerant to the auxiliary heat exchanger side, a pressure increase in the receiver or the like can be suppressed, and thus, damage to the devices can be effectively prevented.

According to the sixth and seventh aspects of the present invention, when the stop command is received before the first set time elapses after the start of the compressor, the residual operation is performed for a long time.
Under conditions where the compressor is repeatedly started and stopped frequently, the liquid refrigerant accumulated in the compressor and the accumulator can be almost recovered to the receiver, and therefore, the failure of the compressor due to dilution of the oil by the liquid refrigerant, etc. Can be effectively prevented.

According to the eighth aspect of the present invention, the auxiliary bypass is provided between the discharge pipe and the liquid line via the auxiliary heat exchanger and the opening and closing mechanism, and the opening and closing mechanism of the auxiliary bypass is opened during the residual operation. With this configuration, the liquid refrigerant remaining in the auxiliary heat exchanger is collected in the receiver, so that the liquid can be more reliably prevented from returning to the compressor.

According to the ninth , tenth , and twelfth aspects of the present invention, when the stop command of the compressor is received from the end of the defrost operation or the oil return operation until the lapse of the second set time, the residual operation is performed for a long time. During the operation of the air-conditioning apparatus, particularly when the defrost or oil return operation in which the refrigerant is on the wet side has not been performed for a long time, the invention according to claims 6 and 7 can be applied. Similarly, failure of the compressor can be effectively prevented.

According to the eleventh aspect of the present invention, an auxiliary bypass path is provided for bypass-connecting the discharge pipe of the compressor and the liquid line via the auxiliary heat exchanger and the opening / closing mechanism. Since the mechanism is opened, the liquid refrigerant of the auxiliary heat exchanger is recovered to the receiver during the residual operation, so that the liquid can be effectively prevented from returning to the compressor. And liquid compression can be prevented.

According to the thirteenth aspect of the present invention, when there is an instruction to start the compressor during the residual operation, the operation is shifted to the normal operation without any change. Can be avoided.

According to the fourteenth aspect of the present invention, when a stop command is issued during the normal operation directly shifted from the residual operation, the time of the normal operation before the residual operation and the time of the normal operation shifted from the residual operation are determined. If the sum exceeds the first set time, the compressor is stopped without performing the residual operation, so that it is possible to avoid deterioration in air conditioning comfort due to extra residual pump down operation.

According to the fifteenth aspect , during the residual operation,
When the low-pressure side pressure is lower than the lower limit pressure, the motor-operated expansion valve on the closed side is opened at a minute opening when the low-pressure side pressure is lower than the lower limit pressure, and when the low-pressure side pressure is higher than the lower limit pressure, the open / close control is performed. The pressure is maintained at or above the pressure, and a long-time residual operation can be secured. Therefore, the liquid refrigerant such as the accumulator can be sufficiently discharged, and the effects of the above-described inventions can be achieved.

According to the sixteenth aspect , when a stop command is received during operation of the air conditioner, when the discharge pipe temperature is equal to or higher than a predetermined temperature, the compressor is stopped without performing residual operation. Therefore, under the humid condition where the accumulation of the liquid refrigerant in the compressor or the like is small, it is possible to avoid the deterioration of the comfort of the air conditioning due to the extra residual operation.

According to the seventeenth aspect , when a stop command is received during operation of the air conditioner, when the oil temperature of the compressor is equal to or higher than a predetermined temperature, the compressor is stopped without performing residual operation. With this configuration, it is possible to avoid the deterioration of the comfort of the air conditioning due to the extra residual operation under the humid condition where the accumulation of the liquid refrigerant in the compressor or the like is small.

[Brief description of the drawings]

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

FIG. 2 is a refrigerant piping system diagram of the air conditioner according to the first embodiment.

FIG. 3 is an electric wiring diagram of the air conditioner according to the first embodiment.

FIG. 4 is a flowchart showing control contents during a cooling operation of the air conditioner.

FIG. 5 is a flowchart showing control contents during a heating operation of the air-conditioning apparatus.

FIG. 6 is a refrigerant piping system diagram of an air conditioner according to a second embodiment.

FIG. 7 is a flowchart showing the control contents of an air conditioner according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 6a, 6b Outdoor heat exchanger 6c Auxiliary heat exchanger 8a1-8b2 Outdoor electric expansion valve 9 Receiver 11e Heating overload control circuit (auxiliary bypass path) 11f Liquid injection bypass path 12 Indoor heat exchanger 13 Indoor electric expansion valve 14 Main refrigerant circuit 40 Liquid seal prevention circuit 41 High pressure control valve 51 Residual operation control means 52 Stop control means 53 Standby operation control means 54 Residual operation avoidance means SVS Overload control valve (opening / closing mechanism) SVL Injection opening / closing valve (opening / closing mechanism) Thd Discharge pipe sensor (discharge pipe temperature detection means) LP Low pressure sensor (low pressure detection means)

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Kiichi Masumo 1304 Kanaokacho, Sakai City, Osaka Daikin Industries, Ltd.Sakai Factory Kanaoka Factory (72) Inventor Yukio Shigenaga 1304, Kanaokacho, Sakai City, Osaka Daikin Industries Inside the Sakai Plant Kanaoka Plant (72) Inventor Hiromune Matsuoka 1304 Kanaoka-cho, Sakai City, Osaka Daikin Industries, Ltd. Inside the Sakai Plant Kanaoka Plant (72) Inventor Akio Higuchi 1304 Kanaoka-cho, Sakai City, Osaka Daikin Plant (56) References JP-A-2-263028 (JP, A) JP 52-41556 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) F25B 1/00 F25B 13/00

Claims (17)

(57) [Claims] 1. Variable displacement compressor (1), outdoor heat exchanger (6), outdoor electric expansion valve (8), receiver (9), indoor electric expansion valve (13), and indoor heat exchanger (12) In the air conditioner provided with the refrigerant circuit (14) in which the compressor (1) is sequentially connected, the indoor electric expansion valve (13) and the outdoor electric expansion valve (8) are closed, and the compressor (1) is closed. A stop control means (52A) for controlling to stop, and when a stop command is received during the cooling operation, the operation of the stop control means (52A) is made to stand by for a predetermined time to reduce the capacity of the compressor (1). Te, bypass open outdoor electric expansion valve (8) to the large opening, and the residual operation control means for controlling to close the indoor motor-operated expansion valve (13) (51A), the discharge pipe of the compressor (1) and a liquid line An auxiliary bypass path (11e) to be connected; Provided 11e), together comprise the auxiliary heat exchanger to assist the condensation capacity and (6c), the opening and closing mechanism for opening and closing the auxiliary bypass path (11e) and (SVS), the residual operation control means (51A ) controls to open the closing mechanism (SVS) of the auxiliary bypass passage for a predetermined time (11e), the outlet end of the auxiliary bypass passage (11e) is connected to the top of the receiver (9) after completion of the control of the residual operation control means (51A), to further wait control for a certain time during the stop control means (52A), the outdoor electric expansion valve (8) and the indoor electric expansion valve (13)
And an open / close mechanism (SVS) for the auxiliary bypass passage (11e), and a standby operation control means (53A) for controlling the compressor (1) to stop. Operation control device. 2. A variable displacement compressor (1), an outdoor heat exchanger (6), an outdoor electric expansion valve (8), a receiver (9), an indoor electric expansion valve (13), and an indoor heat exchanger (12). , The outdoor electric expansion valve (8) is closed, the indoor electric expansion valve (13) is closed to a small opening or less, Stop control means (52) for controlling to stop the compressor (1)
B), when a stop command is received during the heating operation, the operation of the stop control means (52B) is put on standby for a predetermined time, the capacity of the compressor (1) is reduced, and the outdoor electric expansion valve (8) Close
A residual operation control means for controlling to open the indoor electric expansion valve (13) (51B), an auxiliary bypass passage that bypasses connecting the discharge pipe and the liquid line of the compressor (1) and (11e), the auxiliary bypass passage ( provided 11e), an auxiliary heat exchanger to assist the condensation capacity and (6c), provided with a opening and closing mechanism (SVS) for opening and closing the auxiliary bypass path (11e), the residual operation control means ( 51B) controls to open the closing mechanism (SVS) of the auxiliary bypass passage for a predetermined time (11e), the outlet end of the auxiliary bypass passage (11e) is connected to an upper portion of the receiver (9) After the control of the residual operation control means (51B) is completed, the control of the stop control means (52B) is put on standby for a further fixed time,
A standby operation control means (5) for closing the outdoor electric expansion valve (8), opening the opening / closing mechanism (SVS) of the auxiliary bypass passage (11e), and stopping the compressor (1).
An operation control device for an air conditioner, comprising: 3B). 3. A variable displacement compressor (1), an outdoor heat exchanger (6), an outdoor electric expansion valve (8), a receiver (9), an indoor electric expansion valve (13), and an indoor heat exchanger (12). In the air conditioner provided with the refrigerant circuit (14) in which the compressor (1) is sequentially connected, the indoor electric expansion valve (13) and the outdoor electric expansion valve (8) are closed, and the compressor (1) is closed. A stop control means (52A) for controlling to stop, and when a stop command is received during the cooling operation, the operation of the stop control means (52A) is made to stand by for a predetermined time to reduce the capacity of the compressor (1). Te, bypass open outdoor electric expansion valve (8) to the large opening, and the residual operation control means for controlling to close the indoor motor-operated expansion valve (13) (51A), the discharge pipe of the compressor (1) and a liquid line An auxiliary bypass path (11e) to be connected; Provided 11e), an auxiliary heat exchanger to assist the condensation capacity and (6c), provided with a opening and closing mechanism (SVS) for opening and closing the auxiliary bypass path (11e), the residual operation control means ( 51A), said auxiliary bypass passage for a predetermined time period (controls to open the closing mechanism of 11e) (SVS), the auxiliary bypass line (opening and closing mechanism of 11e) (liquid seal prevention circuit that bypasses the SVS) (40) A high pressure control valve (41) interposed in the liquid ring prevention circuit (40) and operable to open when the pressure on the downstream side of the auxiliary bypass passage (11e) becomes higher than the pressure on the upstream side by a predetermined value or more. An operation control device for an air conditioner, comprising: 4. A variable displacement compressor (1), an outdoor heat exchanger (6), an outdoor electric expansion valve (8), a receiver (9), an indoor electric expansion valve (13), and an indoor heat exchanger (12). , The outdoor electric expansion valve (8) is closed, the indoor electric expansion valve (13) is closed to a small opening or less, Stop control means (52) for controlling to stop the compressor (1)
B), when a stop command is received during the heating operation, the operation of the stop control means (52B) is put on standby for a predetermined time, the capacity of the compressor (1) is reduced, and the outdoor electric expansion valve (8) Close
A residual operation control means for controlling to open the indoor electric expansion valve (13) (51B), an auxiliary bypass passage that bypasses connecting the discharge pipe and the liquid line of the compressor (1) and (11e), the auxiliary bypass passage ( provided 11e), an auxiliary heat exchanger to assist the condensation capacity and (6c), provided with a opening and closing mechanism (SVS) for opening and closing the auxiliary bypass path (11e), the residual operation control means ( 51B), said auxiliary bypass passage for a predetermined time period (controls to open the closing mechanism of 11e) (SVS), the auxiliary bypass line (opening and closing mechanism of 11e) (liquid seal prevention circuit that bypasses the SVS) (40) A high pressure control valve (41) interposed in the liquid ring prevention circuit (40) and operable to open when the pressure on the downstream side of the auxiliary bypass passage (11e) becomes higher than the pressure on the upstream side by a predetermined value or more. Equipped Operation control device for air conditioner according to claim. 5. An operation control device for an air conditioner according to claim 1 , wherein the liquid-seal prevention circuit bypasses the opening / closing mechanism (SVS) of the auxiliary bypass passage, and the liquid-seal prevention circuit. (4
0), and a high-pressure control valve (41) that opens when the pressure on the downstream side of the auxiliary bypass passage (11e) becomes higher than the pressure on the upstream side by a predetermined value or more. Operation control device of the harmony device. 6. A variable displacement compressor (1), an outdoor heat exchanger (6), an outdoor electric expansion valve (8), a receiver (9), an indoor electric expansion valve (13), and an indoor heat exchanger (12). , The indoor electric expansion valve (13) and the outdoor electric expansion valve (8) are closed in response to a stop command, and the compressor (1) is turned on. A stop control means (52A) for controlling to stop, and when a stop command is received during the cooling operation, the operation of the stop control means (52A) is made to stand by for a predetermined time to reduce the capacity of the compressor (1). Te, open the outdoor motor-operated expansion valve (8) to the large opening, and a residual operation control means for controlling to close the indoor motor-operated expansion valve (13) (51A), the remaining operation control means (51A) includes a compressor After the start of (1), a stop finger is required until the first set time elapses. Receiving the time was, the accumulator (10) operation control device for air conditioner which is characterized in that the residual operation between long corresponding to the capacity of. 7. A variable displacement compressor (1), an outdoor heat exchanger (6), an outdoor electric expansion valve (8), a receiver (9), an indoor electric expansion valve (13), and an indoor heat exchanger (12). , The outdoor electric expansion valve (8) is closed, the indoor electric expansion valve (13) is closed to a small opening or less, Stop control means (52) for controlling to stop the compressor (1)
B), when a stop command is received during the heating operation, the operation of the stop control means (52B) is put on standby for a predetermined time, the capacity of the compressor (1) is reduced, and the outdoor electric expansion valve (8) Close
And a residual operation control means for controlling to open the indoor electric expansion valve (13) (51B), the residual operation control means (51B) after activation of the compressor (1), until the first predetermined time has elapsed An operation control device for an air conditioner, which performs a residual operation for a long time corresponding to the capacity of the accumulator (10) when a stop command is received. 8. An operation control device for an air conditioner according to claim 6 , wherein an auxiliary bypass path (11e) for bypass-connecting the discharge pipe of the compressor (1) and the liquid line, and the auxiliary bypass path (11e). 11
e), an auxiliary heat exchanger (6c) for assisting the condensing capacity, and an opening / closing mechanism (SVS) for opening and closing the auxiliary bypass passage (11e), and a residual operation control means (51). Is an operation control device for an air conditioner, which controls to open and close the opening and closing mechanism (SVS) of the auxiliary bypass path (11e) for a predetermined time. 9. A variable displacement compressor (1), an outdoor heat exchanger (6), an outdoor electric expansion valve (8), a receiver (9), an indoor electric expansion valve (13), and an indoor heat exchanger (12). , The indoor electric expansion valve (13) and the outdoor electric expansion valve (8) are closed in response to a stop command, and the compressor (1) is turned on. A stop control means (52A) for controlling to stop, and when a stop command is received during the cooling operation, the operation of the stop control means (52A) is made to stand by for a predetermined time to reduce the capacity of the compressor (1). Te, open the outdoor motor-operated expansion valve (8) to the large opening, and a residual operation control means for controlling to close the indoor motor-operated expansion valve (13) (51A), the remaining operation control means (51A) includes a compressor After the start of (1), the defrost operation or the oil return operation ends When the stop command of the compressor (1) is received before the second set time elapses, the remaining operation is performed for a long time corresponding to the capacity of the accumulator (10). Control device. 10. A variable displacement compressor (1), an outdoor heat exchanger (6), an outdoor electric expansion valve (8), a receiver (9), an indoor electric expansion valve (13), and an indoor heat exchanger (12). , The outdoor electric expansion valve (8) is closed, the indoor electric expansion valve (13) is closed to a small opening or less, Stop control means (52) for controlling to stop the compressor (1)
B), when a stop command is received during the heating operation, the operation of the stop control means (52B) is put on standby for a predetermined time, the capacity of the compressor (1) is reduced, and the outdoor electric expansion valve (8) Close
And a residual operation control means for controlling to open the indoor electric expansion valve (13) (51B), the residual operation control means (51B) after activation of the compressor (1), defrost operation or termination of the oil-return operation When the stop command of the compressor (1) is received before the second set time elapses, the residual operation is performed for a long time corresponding to the capacity of the accumulator (10). Control device. 11. An operation control device for an air conditioner according to claim 9 , wherein an auxiliary bypass passage (11e) for bypass-connecting the discharge pipe of the compressor (1) and the liquid line, and the auxiliary bypass passage (11). 11
e), an auxiliary heat exchanger (6c) for assisting the condensing capacity, and an opening / closing mechanism (SVS) for opening and closing the auxiliary bypass passage (11e), and a residual operation control means (51). Is an operation control device for an air conditioner, which controls to open and close the opening and closing mechanism (SVS) of the auxiliary bypass path (11e) for a predetermined time. 12. The operation control device for an air conditioner according to claim 6, wherein the residual operation control means (51) comprises:
When the stop command of the compressor (1) is received before the second set time elapses from the end of the defrost operation or the oil return operation, the residual operation is performed for a long time corresponding to the capacity of the accumulator (10). An operation control device for an air conditioner characterized by the following. 13. The operation control device for an air conditioner according to claim 6, wherein a start command for the compressor (1) is issued during the residual operation by the residual operation control means (51). An operation control device for an air conditioner, comprising: normal operation transition control means for controlling to shift to normal operation as it is. 14. The operation control device for an air conditioner according to claim 13 , wherein when a stop command for the compressor (1) is received after the normal operation is shifted to the normal operation by the normal operation shift control means, the operation before the residual operation is started. When the sum of the continuous operation time of the normal operation and the continuous operation time of the normal operation shifted from the residual operation is longer than the first set time, the operation of the residual operation control means (51) is forcibly stopped and stopped. An operation control device for an air conditioner, comprising a residual operation avoiding means (54A) for shifting to control of the control means (52). 15. The operation control device for an air conditioner according to claim 6, further comprising a low pressure detection means (LP) for detecting a low pressure side pressure of the refrigerant circuit, and a residual operation control means. (51) opens the closed electric expansion valve (13 or 8) to a small opening when the low pressure side pressure is equal to or lower than the lower limit pressure upon receiving the output of the low pressure detection means (LP) during the residual operation. An operation control device for an air conditioner, wherein the operation control device is controlled to close when a low pressure side pressure is higher than a lower limit pressure. 16. An air conditioner operation control device according to claim 6, wherein a discharge pipe temperature detecting means (Thd) for detecting a discharge pipe temperature, and a stop command during operation of the air conditioner. When the discharge pipe temperature detected by the discharge pipe temperature detecting means (Thd) is equal to or higher than a predetermined temperature, the operation of the residual operation control means (51) is forcibly stopped, and the stop control means (52) And a residual operation avoiding means (54B) for shifting to the control of (1). 17. An operation control device for an air conditioner according to claim 6, wherein an oil temperature detecting means for detecting a temperature of lubricating oil of the compressor (1); When the temperature of the lubricating oil detected by the oil temperature detecting means is equal to or higher than a predetermined temperature, the operation of the residual operation control means (51) is forcibly stopped, and the stop control means (52) ), A residual operation avoiding means (54C) for shifting the control to the control of (1).