JP5984747B2 - Air conditioner - Google Patents

Description

The present invention relates to air conditioner having a plurality of flow rate characteristics.

  As an electronic expansion valve of a conventional air conditioner, there are two throttle portions, and the obtained flow rate characteristic changes in principle linearly with respect to the opening degree of the electronic expansion valve (for example, Patent Document 1). reference).

JP 2006-266667 A (FIG. 1)

  However, the conventional electronic expansion valve of an air conditioner has two throttle portions, but the obtained flow rate basically changes linearly with respect to the opening of the electronic expansion valve. There is a problem that only the flow rate of the indoor unit having a limited capacity can be controlled by controlling only the flow rate.

  For example, when an electronic expansion valve corresponding to a large capacity indoor unit is adapted to a small capacity indoor unit, it can handle the capacity sufficiently, but the flow rate change with respect to the change in opening is large, and fine control is not possible. There is a problem that the refrigerant flow rate in the refrigeration cycle during operation hunts greatly, causing a change in refrigerant sound and blowing temperature, which may cause discomfort to the user.

  Conversely, when an electronic expansion valve compatible with a small capacity indoor unit is made compatible with a large capacity indoor unit, the refrigerant flow rate required for the large capacity indoor unit cannot be obtained and sufficient capacity cannot be exhibited. There was a point.

  As described above, when the conventional electronic expansion valve is used for a multi-room air conditioner, indoor units of various capacity classes cannot be connected. Therefore, the B port must be specified for a small capacity indoor unit, and the degree of freedom is extremely small, resulting in a problem of greatly reducing the product capability.

The present invention has been made to solve the above-described problems, and a first object thereof is to obtain an electronic expansion valve that can be adjusted to a refrigerant flow rate that can be applied to air conditioners of various capacities. That is.
A second object is to obtain an air conditioner that can finely control the refrigerant flow rate without causing a sudden change in the refrigeration cycle.
And the 3rd objective is not the electronic expansion valve corresponding to the capacity | capacitance of several indoor units by providing the electronic expansion valve which can respond to the air conditioner of various capacity | capacitance, but the same structure. It is to obtain an air conditioner that can utilize an electronic expansion valve.

An air conditioner according to the present invention is a refrigeration in which a compressor, an outdoor heat exchanger, indoor heat exchangers installed in a plurality of indoor units, and electronic expansion valves connected to the plurality of indoor units are connected by a refrigerant pipe. A cycle unit, and an outdoor control unit that adjusts an opening degree of the electronic expansion valve. The electronic expansion valve includes a cylindrical valve seat having an inner peripheral edge, and the inner peripheral edge on the distal end side. A needle portion that forms a flow path therebetween, wherein the needle portion has a tapered portion having a taper angle with respect to an axial direction of the needle portion, and the tapered portion is the tip of the needle portion. A maximum taper angle portion having the largest taper angle in order from the side, and a minimum taper angle portion having a taper angle smaller than the maximum taper angle portion. Machine and the large capacity room A small-capacity indoor unit having a smaller capacity than the unit, and the outdoor control unit forms the large-capacity indoor unit with the flow path formed by the maximum taper angle portion and the inner peripheral edge portion of the electronic expansion valve. The small capacity indoor unit is operated in a state where the flow path is formed by the minimum taper angle portion and the inner peripheral edge portion of the electronic expansion valve.

  According to the present invention, the degree of opening of the electronic expansion valve, that is, the flow rate can be controlled according to the capacity class of the connected refrigeration cycle, and the refrigerant flow rate can be adjusted to the capacity of the refrigeration cycle. The refrigeration cycle can exhibit an appropriate capacity and can realize efficient operation.

It is a refrigerant circuit diagram of the air conditioner according to Embodiment 1 of the present invention. It is a block diagram of the electronic expansion valves 4a-4d which concern on Embodiment 1 of this invention. It is a graph which shows the relationship between the operation amount (pulse) with respect to the electronic expansion valves 4a-4d which concern on Embodiment 1 of this invention, and the flow rate ratio in the opening degree decided by the operation amount. The specific example of the flowchart of the operation | movement which changes a flow volume with the operation amount (pulse) with respect to the electronic expansion valves 4a-4d of the air conditioner which concerns on Embodiment 2 of this invention is shown. Together with a graph showing the relationship between the operation amount (pulse) for the electronic expansion valves 4a to 4d of the air conditioner according to Embodiment 2 of the present invention and the flow rate ratio at the opening determined by the operation amount, the request pulse is changed to other pulses. It is a figure which shows the operation | movement converted into.

Embodiment 1 FIG.
(Configuration of air conditioner)
FIG. 1 is a refrigerant circuit diagram of an air conditioner according to Embodiment 1 of the present invention.
As shown in FIG. 1, the air conditioner according to the present embodiment includes at least a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, electronic expansion valves 4a to 4d, and indoor heat exchangers 5a to 5d. The compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the electronic expansion valves 4a to 4d, the indoor heat exchangers 5a to 5d, the four-way valve 2, and the compressor 1 are connected by the refrigerant pipe in this order. It constitutes the refrigeration cycle. The air conditioner according to the present embodiment includes an outdoor control unit 6 that controls operations of the compressor 1, the four-way valve 2, the electronic expansion valves 4a to 4d, and the like.

  The compressor 1 is rotationally driven at a rotational speed based on a command from the outdoor control unit 6, compresses the inflowing gas refrigerant, and discharges the high-temperature and high-pressure gas refrigerant.

  The four-way valve 2 switches the refrigerant flow path corresponding to the heating operation or the cooling operation.

  The outdoor heat exchanger 3 exchanges heat with the refrigerant that flows in with the outside air. In the case of cooling operation, the outdoor heat exchanger 3 functions as a condenser, heat-condenses the high-temperature and high-pressure gas refrigerant that has flowed into the outside air, condenses, and flows out as high-pressure liquid refrigerant. On the other hand, in the case of heating operation, the outdoor heat exchanger 3 functions as an evaporator, heat-exchanges the low-pressure two-phase refrigerant that has flowed in with the outside air, evaporates, and flows out as a low-pressure gas refrigerant.

  The electronic expansion valves 4 a to 4 d are configured to control the flow rate of the refrigerant by adjusting the opening degree based on a command from the outdoor control unit 6. Details of the configuration of the electronic expansion valves 4a to 4d will be described later with reference to FIG.

  The indoor heat exchangers 5a to 5d are provided in the indoor units 10a to 10d, respectively, and allow the refrigerant that has flowed in to exchange heat with room air. In the case of the cooling operation, the indoor heat exchangers 5a to 5d function as an evaporator, heat-exchange the inflowing low-pressure two-phase refrigerant with room air, and evaporate to flow out as a low-pressure gas refrigerant. On the other hand, in the case of heating operation, the indoor heat exchangers 5a to 5d function as condensers, condense the inflowing high-temperature and high-pressure gas refrigerant with room air, condense, and flow out as high-pressure liquid refrigerant.

  As described above, the outdoor control unit 6 controls the operations of the compressor 1, the four-way valve 2, the electronic expansion valves 4a to 4d, and the like, and in particular, opens the electronic expansion valves 4a to 4d as described later. The degree adjustment is controlled based on a request pulse (requested operation amount) from the indoor unit.

(Configuration of electronic expansion valves 4a to 4d)
FIG. 2 is a configuration diagram of the electronic expansion valves 4a to 4d according to the first embodiment of the present invention.
As shown in FIG. 2, the electronic expansion valves 4 a to 4 d include an electronic expansion valve needle portion 7 and a valve seat 8 that forms a gap with the tip of the electronic expansion valve needle portion 7.

  The electronic expansion valve needle portion 7 has a needle minimum taper angle (θ3) portion 7a, a needle intermediate taper angle (θ2) portion 7b, and a needle maximum taper angle (θ1) portion 7c at the tip portion, and each taper is tapered. It has a three-stage structure with different corners. Here, the taper angle refers to the angle of the surface of the taper portion with respect to the axial direction of the electronic expansion valve needle portion 7. Each taper angle portion is formed so that the taper angle has a relationship of θ3> θ2> θ1. A channel 9 is formed by these tapered corners and the inner peripheral edge of the valve seat 8. The flow rate flowing through the flow path 9 is determined by the positional relationship between the inner peripheral edge of the valve seat 8 and each Taber corner of the electronic expansion valve needle 7, and the outdoor control unit 6 pivots on the electronic expansion valve needle 7. By operating in the direction, the flow rate of the refrigerant is adjusted.

(Air conditioning operation of air conditioner)
Next, the air conditioning operation of the air conditioner according to the present embodiment will be described. During the cooling operation, the outdoor control unit 6 first switches the four-way valve 2 to a flow path corresponding to the cooling operation. The high-temperature and high-pressure gas refrigerant compressed by the compressor 1 flows into the outdoor heat exchanger 3 via the four-way valve 2. The gas refrigerant that has flowed into the outdoor heat exchanger 3 undergoes heat exchange with the outside air, condenses, flows out as a high-pressure liquid refrigerant, and is distributed and flows into the electronic expansion valves 4a to 4d. The liquid refrigerant flowing into the electronic expansion valves 4a to 4d is expanded and decompressed, flows out as a low-pressure two-phase refrigerant, and flows into the indoor heat exchangers 5a to 5d in the indoor units 10a to 10d. The two-phase refrigerant that has flowed into the indoor heat exchangers 5a to 5d undergoes heat exchange with room air, evaporates, and flows out as low-pressure gas refrigerant. At this time, the air cooled by the heat exchange with the refrigerant is blown into the room as cold air by a blower fan (not shown). The gas refrigerant that has flowed out of the indoor heat exchangers 5a to 5d flows into the compressor 1 via the four-way valve 2, and is compressed again.

  Further, during the heating operation, the outdoor control unit 6 first switches the four-way valve 2 to a flow path corresponding to the heating operation. The high-temperature and high-pressure gas refrigerant compressed by the compressor 1 is distributed and flows through the four-way valve 2 to the indoor heat exchangers 5a to 5d in the indoor units 10a to 10d. The gas refrigerant that has flowed into the indoor heat exchangers 5a to 5d undergoes heat exchange with room air, condenses, flows out as high-pressure liquid refrigerant, and flows into the electronic expansion valves 4a to 4d. At this time, the air heated by the heat exchange with the refrigerant is blown into the room as warm air by a blower fan (not shown). The liquid refrigerant flowing into the electronic expansion valves 4 a to 4 d is expanded and decompressed, flows out as a low-pressure two-phase refrigerant, and flows into the outdoor heat exchanger 3. The two-phase refrigerant that has flowed into the outdoor heat exchanger 3 undergoes heat exchange with the outside air, evaporates, and flows out as a low-pressure gas refrigerant. The gas refrigerant that has flowed out of the outdoor heat exchanger 3 flows into the compressor 1 via the four-way valve 2 and is compressed again.

(Flow adjustment operation of the electronic expansion valves 4a to 4d)
FIG. 3 is a graph showing a relationship between an operation amount (pulse) for the electronic expansion valves 4a to 4d according to Embodiment 1 of the present invention and a flow rate ratio at an opening determined by the operation amount.
In the operation of the air conditioner according to the present embodiment as described above, the distribution of the refrigerant flow rate to the indoor heat exchangers 5a to 5d is performed in the electronic expansion valves 4a to 4d in both the cooling operation and the heating operation. This is implemented by the operation of the unit 7. The indoor control unit (not shown) in each of the indoor units 10a to 10d transmits information on how much its own ability class is to the outdoor control unit 6, and the outdoor control unit 6 that has received the information is It is determined to which ability class the machines 10a to 10d belong. At this time, in the electronic expansion valve needle part 7 of the electronic expansion valves 4a to 4d, the needle minimum taper angle part 7a is used for an indoor unit having a small capacity (for example, 1.5 kW <capacity ≦ 4.0 kW). The portion 7b is for an indoor unit having a medium capacity (for example, 4.0 kW <capacity ≦ 6.0 kW), and the needle maximum taper corner portion 7c is a room having a large capacity (for example, 6.0 kW <capacity ≦ 8.0 kW). It corresponds to the machine use.

  For the small capacity indoor unit, the outdoor control unit 6 has its electronic expansion so that the flow path 9 is determined by the needle minimum taper angle portion 7a of the corresponding electronic expansion valve and the inner peripheral edge of the valve seat 8. An operation amount (pulse) is transmitted to the valve to move the electronic expansion valve needle portion 7 in the axial direction. In addition, the outdoor control unit 6 is configured so that the flow path 9 is determined by the needle intermediate taper corner portion 7b of the corresponding electronic expansion valve and the inner peripheral edge portion of the valve seat 8 for the indoor unit of medium capacity. An operation amount (pulse) is transmitted to the electronic expansion valve to move the electronic expansion valve needle portion 7 in the axial direction. The outdoor control unit 6 is configured so that, for a high-capacity indoor unit, the flow path 9 is determined by the needle maximum taper corner portion 7c of the corresponding electronic expansion valve and the inner peripheral edge portion of the valve seat 8. An operation amount (pulse) is transmitted to the electronic expansion valve to move the electronic expansion valve needle portion 7 in the axial direction.

For a small capacity indoor unit, the flow path 9 is determined by the needle minimum taper angle portion 7a of the electronic expansion valve and the inner peripheral edge of the valve seat 8 depending on the range of the operation amount for the electronic expansion valve of 0 <pulse ≦ x1. And the flow rate ratio increases as the manipulated variable increases due to the inclination shown in FIG.
Further, for an indoor unit of medium capacity, depending on the range of the operation amount for the electronic expansion valve of x1 <pulse ≦ x2, the flow is caused by the needle intermediate taper corner 7b of the electronic expansion valve and the inner peripheral edge of the valve seat 8. The path is determined, and the flow rate ratio increases as the operation amount increases due to the inclination as shown in FIG. At this time, the rate of change of the flow rate ratio relative to the manipulated variable is larger than in the case of a small capacity indoor unit.
For a high-capacity indoor unit, the flow rate is controlled by the needle maximum taper corner 7c of the electronic expansion valve and the inner peripheral edge of the valve seat 8, depending on the range of operation amount for the electronic expansion valve of x2 <pulse ≦ x3. The path is determined, and the flow rate ratio increases as the operation amount increases due to the inclination as shown in FIG. At this time, the rate of change of the flow rate ratio with respect to the manipulated variable is larger than that of the small capacity and medium capacity indoor units.

In addition, the indoor control unit (not shown) in each of the indoor units 10a to 10d transmits information on how much its ability class is to the outdoor control unit 6, and the outdoor control unit 6 that has received the information is In this case, the outdoor control unit 6 determines an operation amount (pulse) representing the determined capability class (for example, an operation at a small capability). Since the range of the amount is 0 <pulse ≦ x1, the intermediate operation value x1 / 2) may be transmitted to the electronic expansion valves corresponding to the indoor units 10a to 10d.
Alternatively, the indoor control unit may transmit the operation amount information for the electronic expansion valve directly to the outdoor control unit 6 as information on how much of its own ability class. In this case, the outdoor control unit 6 The received operation amount may be transmitted to the electronic expansion valve as it is. As a result, it is determined which taper corner portion forms the flow path 9, and the ability class is also determined.
Furthermore, the indoor control unit may transmit the flow rate information of the refrigerant corresponding to the capability class to the outdoor control unit 6 as information on how much its capability class is. In this case, the outdoor control unit 6 may convert the required operation amount (pulse) based on the received flow rate information into the required operation amount (pulse) and transmit it to the electronic expansion valve. . As a result, it is determined which taper corner portion forms the flow path 9, and the ability class is also determined.

(Effect of Embodiment 1)
With the above configuration and operation, the outdoor control unit 6 controls the opening degree of the electronic expansion valve corresponding to the indoor unit, that is, the flow rate, according to the information regarding the capability class transmitted from the indoor control unit in the indoor unit. Thus, the refrigerant flow rate can be adjusted to correspond to the capacity of the indoor unit, so that the indoor unit can exhibit an appropriate capacity and can realize an efficient air conditioning operation. Further, by using the electronic expansion valve as described above, it is possible to cope with an indoor unit having a very wide capacity band (1.5 kW to 8.0 kW in the present embodiment).

  In the refrigerant circuit of the air conditioner shown in FIG. 1, the four indoor units 10a to 10d are provided. However, the configuration is not limited to this, and one or other units are provided. The indoor unit may be provided, and the same number of electronic expansion valves may be provided. At this time, when a plurality of indoor units are provided, it is not necessary to provide an electronic expansion valve having a different configuration and specification in order to correspond to the capacity of each indoor unit, and the electronic expansion valve according to the present embodiment is shared. Can be used.

  In addition, as shown in FIG. 3, the indoor unit capacity class is divided into three categories such as small capacity, medium capacity, and large capacity, but is not limited to this. It is good also as a division of the number of. In this case, the taper angle portion of the electronic expansion valve needle portion 7 of the electronic expansion valve may be formed so as to have a different taper angle by the same number as that of the segment according to the number of the segments. As a result, it can be applied to a wider variety of indoor unit capacity classes, and finer control can be realized.

  In addition, the electronic expansion valve according to the present embodiment is applied to an air conditioner, but is not limited to this, and can be applied to a refrigerator, a heat pump device, or other devices equipped with a refrigeration cycle. This is possible and can be adjusted to a refrigerant flow rate corresponding to the capacity of the refrigeration cycle.

Embodiment 2. FIG.
In Embodiment 1, according to the capability classes of the indoor units 10a to 10d, the outdoor control unit 6 controls the flow rate by controlling the electronic expansion valve needle unit 7 of the electronic expansion valves 4a to 4d in the axial direction. Although shown, in this Embodiment, the operation | movement when it is necessary to operate | move with the flow volume in capability classes other than the capability class corresponding to indoor unit 10a-10d is demonstrated.

  The air conditioner according to the present embodiment will be described focusing on differences from the operation of the air conditioner according to the first embodiment. The configurations of the air conditioner and the electronic expansion valves 4a to 4d according to the present embodiment are the same as the configurations of the first embodiment.

(About the case of operating by the flow in the ability class other than the corresponding ability class)
As described in the first embodiment, the flow rate of the electronic expansion valves 4a to 4d can be controlled in accordance with the capacity class of each indoor unit 10a to 10d as long as the air conditioner is in a normal state. Depending on the driving condition, it may be necessary to use it outside the scope of the ability class.

  First, a description will be given of a case where a small-capacity indoor unit is operated at a medium capacity, and a medium-capacity indoor unit is operated at a higher capacity class flow rate as in the case of operating at a large capacity flow rate. Such a situation can be considered, for example, when an unexpected overload condition occurs and the refrigerant flow rate suddenly increases. In this case, in order for the indoor control unit of the indoor unit to obtain the required refrigerant flow rate, based on equations (1) to (3) described later, which are relational expressions between the operation amount and the flow rate ratio in the current capacity class. When the outdoor control unit 6 controls the opening of the electronic expansion valve by the operation amount (pulse), the operation amount (pulse) is higher. When it belongs to the capacity class, the flow rate changes too rapidly, and the refrigeration cycle becomes very unstable. Therefore, in the air conditioner according to the present embodiment, as described above, even if the operation amount (pulse) received from the indoor control unit belongs to the higher-level capability class, the outdoor control unit 6 Calculate the flow ratio based on the relational expression between the manipulated variable and the flow ratio in the class, and calculate the higher flow rate based on the calculated flow ratio and the relational expression between the manipulated variable and the flow ratio in the higher ability class. It converts into the operation amount (pulse) which becomes the same flow rate ratio in a capability class, and the opening degree of an electronic expansion valve is adjusted with the converted operation amount (pulse). As a result, even when an unexpected overload condition occurs and the refrigerant circulation amount suddenly increases, the refrigeration cycle does not become unstable, and the flow rate control can be performed stably.

  Next, a description will be given of a case where a high-capacity indoor unit is operated at a medium capacity, and a medium-capacity indoor unit is operated at a lower capacity class flow rate, such as when the medium capacity indoor unit is operated at a low capacity flow rate. Such a situation is, for example, when the filter of the indoor unit is clogged, or when the air temperature is suddenly lowered, etc., and heat exchange between the refrigerant and the air is not sufficiently performed, and the refrigerant flow rate suddenly increases. The case where it falls, etc. can be considered. In this case, the indoor control unit of the indoor unit is based on equations (1) to (3), which will be described later, which are relational expressions between the operation amount and the flow rate ratio in the current capacity class in order to obtain the required refrigerant flow rate. When the outdoor control unit 6 controls the opening degree of the electronic expansion valve by the operation amount (pulse), the operation amount (pulse) is lower order. Therefore, the desired refrigerant flow rate cannot be obtained. Therefore, in the air conditioner according to the present embodiment, as described above, even if the operation amount (pulse) received from the indoor control unit belongs to the lower capability class, the outdoor control unit 6 The flow rate ratio is calculated based on the relational expression between the manipulated variable and the flow rate ratio in the class, and the subordinate expression based on the calculated flow rate ratio and the relational expression between the manipulated variable and the flow rate ratio in the lower ability class. It converts into the operation amount (pulse) which becomes the same flow rate ratio in a capability class, and the opening degree of an electronic expansion valve is adjusted with the converted operation amount (pulse). Thereby, even when the filter of the indoor unit is clogged or when the air temperature is drastically lowered, a desired refrigerant flow rate can be obtained and the refrigeration cycle can be stably controlled.

  FIG. 4 shows a specific example of a flowchart of the operation of changing the flow rate by the operation amount (pulse) for the electronic expansion valves 4a to 4d of the air conditioner according to Embodiment 2 of the present invention. The figure which shows the operation | movement which converts the request | requirement pulse into another pulse with the graph which shows the relationship between the operation amount (pulse) with respect to the electronic expansion valves 4a-4d of the same air conditioner, and the flow rate ratio in the opening degree determined by the operation amount. is there.

  As shown in FIG. 5, the equations showing the graphs of the operation amount and the flow rate ratio corresponding to the small capacity, medium capacity, and large capacity indoor units are expressed by the following expressions (1) to (3), respectively. Shall be.

y = a1 · x + b1 (small ability) (1)
y = a2 · x + b2 (medium ability) (2)
y = a3 · x + b3 (high capacity) (3)

  Hereinafter, with reference to FIG. 4 and FIG. 5, focusing on one of the installed indoor units 10a to 10d, it is assumed that the indoor unit belongs to a medium capacity class and corresponds to the indoor unit. An operation for adjusting the opening of the electronic expansion valve to a different flow rate will be described.

(S1)
It is assumed that the outdoor control unit 6 receives information on which capability class the indoor unit belongs to from the indoor control unit of the indoor unit, and determines that it is a capability class of medium capability based on the information.

(S2)
The outdoor control unit 6 changes the opening degree by transmitting an operation amount (pulse) belonging to x1 <pulse ≦ x2 to the electronic expansion valve corresponding to the indoor unit among the electronic expansion valves 4a to 4d. Adjust the refrigerant flow rate.

(S3)
The indoor unit's indoor control unit suddenly changes the refrigerant flow rate when an unexpected overload condition occurs, when the filter of the indoor unit is clogged, or when the air temperature drops rapidly. Then, based on the equation (2), the operation amount (pulse) corresponding to the refrigerant flow rate is calculated as the request pulse A1, and transmitted to the outdoor control unit 6.

(S4)
The outdoor control unit 6 determines whether the request pulse A1 received from the indoor control unit belongs to x1 <pulse ≦ x2. As a result of the determination, if the request pulse A1 belongs to x1 <pulse ≦ x2, the process proceeds to step S5. On the other hand, if the request pulse A1 does not belong to x1 <pulse ≦ x2, the process proceeds to step S6.

(S5)
The outdoor control unit 6 changes the opening degree by transmitting a request pulse A1 to the electronic expansion valve to adjust the refrigerant flow rate.

(S6)
The outdoor control unit 6 determines whether or not the request pulse A1 received from the indoor control unit belongs to 0 <pulse ≦ x1. As a result of the determination, if the request pulse A1 belongs to 0 <pulse ≦ x1, the process proceeds to step S7. On the other hand, if the request pulse A1 does not belong to 0 <pulse ≦ x1, the process proceeds to step S10.

(S7)
The outdoor control unit 6 calculates the required refrigerant flow rate based on the following equation (4) based on the request pulse A1 and equation (2).

  y = a2 · A1 + b2 (4)

(S8)
The outdoor control unit 6 belongs to 0 <pulse ≦ x1, which is a small capacity manipulated variable range, based on the calculated required refrigerant flow rate and the following formula (5) based on the formula (1) corresponding to the small capacity. The output pulse B1 is calculated.

  B1 = (a2.A1 + b2-b1) / a1 (5)

(S9)
The outdoor control unit 6 changes the opening degree by transmitting the calculated output pulse B1 to the electronic expansion valve, thereby reducing the refrigerant flow rate.

(S10)
The outdoor control unit 6 determines whether the request pulse A1 received from the indoor control unit belongs to x2 <pulse ≦ x3. As a result of the determination, when the request pulse A1 belongs to x2 <pulse ≦ x3, the process proceeds to step S11. On the other hand, if the request pulse A1 does not belong to x2 <pulse ≦ x3, the process returns to step S3.

(S11)
The outdoor control unit 6 calculates the required refrigerant flow rate based on the request pulse A1 and the above formula (4) based on the formula (2).

(S12)
The outdoor control unit 6 belongs to the large-capacity manipulated variable range x2 <pulse ≦ x3 based on the calculated necessary refrigerant flow rate and the following formula (6) based on the formula (3) corresponding to the large capacity. The output pulse B2 is calculated.

  B2 = (a2 · A1 + b2-b3) / a3 (6)

(S13)
The outdoor control unit 6 changes the opening degree by transmitting the calculated output pulse B2 to the electronic expansion valve, and increases the refrigerant flow rate.

  In addition, the relational expression between the operation amount and the flow rate ratio in each capability class represented by the above formulas (1) to (3) corresponds to the “refrigerant flow rate characteristic” of the present invention, and the output pulses B1 and B2 are This corresponds to the “output operation amount” of the present invention.

(Effect of Embodiment 2)
When the refrigerant flow rate is adjusted from the normal capability class to the other capability class as described above, the outdoor control unit 6 once determines the relationship between the operation amount and the flow rate ratio in the normal capability class from the request pulse. Calculate the required refrigerant flow rate based on the equation, and based on the relational expression between the required refrigerant flow rate and the operation amount and flow rate ratio in the other capability class to which the request pulse belongs, By converting to an output pulse that can be circulated and adjusting the refrigerant flow rate by the electronic expansion valve based on the output pulse, stable flow rate control can be performed without destabilizing the refrigeration cycle. .

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 Four way valve, 3 Outdoor heat exchanger, 4a-4d Electronic expansion valve, 5a-5d Indoor heat exchanger, 6 Outdoor control part, 7 Electronic expansion valve needle part, 7a Needle minimum taper angle ((theta) 3) part 7b Needle intermediate taper angle (θ2) portion, 7c Needle maximum taper angle (θ1) portion, 8 valve seat, 9 flow path, 10a to 10d indoor unit.

Claims (1)

A refrigeration cycle unit in which a compressor, an outdoor heat exchanger, indoor heat exchangers installed in a plurality of indoor units, an electronic expansion valve connected to the plurality of indoor units are connected by a refrigerant pipe, and the electronic expansion valve An outdoor control unit for adjusting the opening degree,
  The electronic expansion valve is
  A cylindrical valve seat having an inner peripheral edge;
  A needle part that forms a flow path between the inner peripheral edge part on the distal end side, and
  The needle part is
  A taper portion having a taper angle with respect to the axial direction of the needle portion;
  The tapered portion is
  A maximum taper angle portion having the largest taper angle in order from the tip side of the needle portion, and a minimum taper angle portion having a smaller taper angle than the maximum taper angle portion,
  The plurality of indoor units are:
  A large-capacity indoor unit having the largest capacity, and a small-capacity indoor unit having a smaller capacity than the large-capacity indoor unit,
  The outdoor control unit is
  The large capacity indoor unit is operated in a state where the flow path is formed by the maximum taper angle portion and the inner peripheral edge of the electronic expansion valve, and the small capacity indoor unit is operated with the minimum of the electronic expansion valve. An air conditioner that operates in a state where the flow path is formed by a taper corner and the inner peripheral edge.

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