WO2015111379A1

WO2015111379A1 - Freeze cycling device

Info

Publication number: WO2015111379A1
Application number: PCT/JP2015/000094
Authority: WO
Inventors: 桑原　幹治
Original assignee: 株式会社デンソー
Priority date: 2014-01-21
Filing date: 2015-01-12
Publication date: 2015-07-30
Also published as: JP2015137778A

Abstract

　In this freeze cycling device, there is employed as an evaporation pressure regulating valve (19) one in which the extent of increase in the refrigerant passage area with respect to increase in the amount of displacement (L) of a cylindrical valve body (92) is greater than the extent of increase that would be observed in the case of linear increase in proportion to an increase in the amount of displacement (L); and the set pressure (Pset) is lower than the target evaporation pressure (PEO). Further, the operation of the compressor (11) is controlled in such a way that the refrigerant evaporation pressure (Pe) in the evaporator is brought into approximation to the target evaporation pressure (PEO), the value of which is the higher of the set pressure (Pset) and the target evaporation pressure (PEO). In so doing, control interference occurring due to the use of the evaporation pressure regulating valve (19) is minimized, and the cooling performance required of an indoor evaporator can be produced, without unnecessarily increasing the power consumed by the compressor.

Description

Refrigeration cycle equipment

Cross-reference of related applications

This application is based on Japanese Patent Application No. 2014-008372 filed on January 21, 2014, the disclosure of which is incorporated herein by reference.

The present disclosure relates to a refrigeration cycle apparatus including an evaporation pressure adjustment valve.

Conventionally, a vapor compression type refrigeration cycle apparatus that cools blown air blown into a passenger compartment of a vehicle air conditioner is known that includes an evaporation pressure adjusting valve. This type of evaporation pressure regulating valve is configured to reduce the refrigerant evaporation pressure (refrigerant evaporation) in the indoor evaporator in order to suppress frosting (frost) of the indoor evaporator that evaporates the low-pressure refrigerant by exchanging heat between the low-pressure refrigerant and the blown air. The temperature is maintained at a predetermined reference evaporation pressure (reference evaporation temperature) or higher.

For example, Patent Document 1 discloses an evaporation pressure adjusting valve that increases a valve opening (refrigerant passage area) with an increase in the flow rate of refrigerant flowing through an indoor evaporator. More specifically, the evaporating pressure adjusting valve of Patent Document 1 is connected to the refrigerant outlet side of the indoor evaporator to increase the flow rate of refrigerant flowing through the indoor evaporator (the flow rate of refrigerant flowing through the evaporating pressure adjusting valve). The set pressure increases in proportion to the accompanying increase in the displacement of the valve body.

The reference evaporation temperature is a constant determined to be higher than 0 ° C. in order to suppress frost formation (frost) of the indoor evaporator. The set pressure of the evaporating pressure adjusting valve is the refrigerant pressure on the inlet side of the evaporating pressure adjusting valve when the evaporating pressure adjusting valve in the fully opened state starts to reduce the refrigerant passage area (refrigerant evaporation in the indoor evaporator). Pressure), which varies depending on the flow rate of the refrigerant flowing through the evaporation pressure regulating valve.

Further, in Patent Document 2, in addition to the indoor evaporator and the evaporation pressure regulating valve, an indoor condenser for exchanging heat between the high-pressure refrigerant discharged from the compressor and the blown air after passing through the indoor evaporator, and the indoor evaporator A refrigeration cycle apparatus is disclosed that includes an outdoor heat exchanger in which refrigerant flows are connected in parallel to exchange heat between low-pressure refrigerant and outside air to evaporate the low-pressure refrigerant.

In the refrigeration cycle apparatus of Patent Document 2, the refrigerant evaporating pressure in the outdoor heat exchanger is made lower than the refrigerant evaporating pressure in the indoor evaporator by the action of the evaporating pressure adjusting valve. Thereby, while suppressing frost formation of the indoor evaporator, the amount of heat absorbed by the refrigerant from the outside air is increased in the outdoor heat exchanger, and the blown air dehumidified by cooling in the indoor evaporator is removed from the indoor condenser. The heating capacity at the time of dehumidification heating operation reheating at is improved.

Japanese Utility Model Publication No.57-23747 JP 2012-225637 A

According to studies by the inventors of the present disclosure, in a general vehicle air conditioner, the target refrigerant in the indoor evaporator is used so that the refrigeration cycle apparatus exhibits a high cooling capacity as the cooling heat load increases. Reduce evaporation temperature. Then, in order to bring the actual refrigerant evaporation temperature in the indoor evaporator closer to the target refrigerant evaporation temperature, the refrigerant discharge capacity (rotation speed) of the compressor is increased.

However, in the refrigeration cycle apparatus having an evaporation pressure adjusting valve as disclosed in Patent Document 1, when the refrigerant discharge capacity of the compressor is increased to increase the flow rate of refrigerant flowing through the indoor evaporator, the evaporation pressure adjusting valve Therefore, the refrigerant evaporation pressure (refrigerant evaporation temperature) in the indoor evaporator also increases.

As a result, even if the refrigerant discharge capacity of the compressor is increased, a control interference occurs in which the refrigerant evaporation temperature in the evaporator cannot be lowered until the target refrigerant evaporation temperature is reached. Further, when such control interference occurs, the rotation speed of the compressor is unnecessarily increased in order to bring the refrigerant evaporation temperature in the indoor evaporator closer to the target refrigerant evaporation temperature, thereby increasing the power consumption of the compressor. End up.

In view of the above points, the present disclosure aims to suppress an unnecessary increase in power consumption of a compressor in a refrigeration cycle apparatus including an evaporation pressure adjusting valve.

A refrigeration cycle apparatus according to an aspect of the present disclosure includes a compressor that compresses and discharges a refrigerant, an outdoor heat exchanger that exchanges heat between the refrigerant discharged from the compressor and outside air, and a refrigerant that has flowed out of the outdoor heat exchanger A decompressor for reducing the pressure, an evaporator for exchanging heat between the low-pressure refrigerant decompressed by the decompressor and the heat exchange target fluid, and evaporating the low-pressure refrigerant, and a refrigerant evaporation pressure in the evaporator is equal to or higher than a predetermined reference evaporation pressure An evaporating pressure adjusting valve that adjusts the target evaporating pressure, a target evaporating pressure determining unit that determines a target evaporating pressure in the evaporator, and a discharge capacity control unit that controls the operation of the compressor.

The target evaporating pressure determining unit determines that the target evaporating pressure is reduced as the cooling capacity of the heat exchange target fluid required for the evaporator increases, and the evaporating pressure adjusting valve circulates the evaporator. As the refrigerant flow rate increases, the set pressure increases. The target evaporation pressure determination unit is adjusted so that the refrigerant evaporation pressure approaches the higher of the target evaporation pressure and the set pressure when the discharge capacity control unit controls the operation of the compressor.

In the present disclosure, the set pressure is the evaporation pressure when the evaporation pressure regulating valve in the fully open state starts to reduce the refrigerant passage area in order to maintain the refrigerant evaporation temperature in the evaporator above the reference evaporation temperature. This is the refrigerant pressure at the inlet side of the regulating valve (refrigerant evaporation pressure in the evaporator). Furthermore, this set pressure is a value that varies depending on the flow rate of the refrigerant flowing through the evaporation pressure adjusting valve.

Therefore, when the target evaporation pressure is higher than the set pressure, the operation of the compressor is controlled so that the refrigerant evaporation pressure approaches the target evaporation pressure. Thereby, the cooling capacity required for the evaporator can be exhibited without unnecessarily increasing the power consumption of the compressor.

Also, when the set pressure is higher than the target evaporation pressure, the operation of the compressor is controlled so that the refrigerant evaporation pressure approaches the set pressure. As a result, it is possible to avoid control interference caused by trying to bring the refrigerant evaporation pressure closer to the target evaporation pressure. Therefore, it is possible to suppress an unnecessary increase in power consumption of the compressor.

In the present disclosure, the cooling ability of the heat exchange target fluid required for the evaporator is the ability to cool the heat exchange target fluid at a desired flow rate to a desired temperature in the evaporator, specifically, It can be defined using a value obtained by integrating the enthalpy difference (refrigeration capacity) obtained by subtracting the enthalpy of the inlet side refrigerant from the enthalpy of the evaporator outlet side refrigerant and the flow rate (mass flow rate) of the refrigerant flowing through the evaporator. .

Furthermore, in the refrigeration cycle apparatus of the present disclosure, the evaporating pressure adjusting valve is configured such that the refrigerant passage area inside increases as the refrigerant evaporating pressure increases, and the refrigerant passage increases as the refrigerant evaporating pressure increases. The degree of increase when the area increases may be larger than the degree of increase when the refrigerant passage area increases linearly in proportion to the increase in the refrigerant evaporation pressure.

According to this, as will be described later in an embodiment, the evaporator passage area of the evaporation pressure regulating valve increases linearly in proportion to the increase in the flow rate of the refrigerant flowing through the evaporator. The degree of increase in the set pressure accompanying an increase in the flow rate of the refrigerant flowing through can be reduced.

As a result, the refrigerant flow rate range in which the target evaporation pressure becomes higher than the set pressure can be expanded, and the cooling capacity required for the evaporator can be exhibited without unnecessarily increasing the power consumption of the compressor. The range of the refrigerant flow rate can be expanded.

Furthermore, in the refrigeration cycle apparatus, the discharge capacity control unit may control the operation of the compressor so as to suppress the evaporation pressure regulating valve from decreasing the internal refrigerant passage area. According to this, when the set pressure is higher than the target evaporation pressure, the refrigerant evaporation pressure can be easily brought close to the set pressure.

1 is an overall configuration diagram of a vehicle air conditioner according to a first embodiment. It is an axial sectional view of the evaporation pressure regulating valve of the first embodiment. It is a side view of the cylindrical valve body part of the evaporation pressure regulating valve of the first embodiment. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. It is a graph which shows the relationship between the displacement amount of the cylindrical valve body part in the evaporation pressure regulating valve of 1st Embodiment, and a refrigerant passage area. It is a graph which shows the relationship between the refrigerant | coolant flow volume and setting pressure in the evaporation pressure regulating valve of 1st Embodiment. It is a block diagram which shows the electric control part of the vehicle air conditioner of 1st Embodiment. It is a flowchart which shows the control processing of the vehicle air conditioner of 1st Embodiment. It is a flowchart for determining an operation mode among control processing of the air-conditioner for vehicles of a 1st embodiment. It is a figure which shows the operating state of the various air-conditioning control apparatus in each operation mode of 1st Embodiment. It is a flowchart for demonstrating the principal part of the control processing of the vehicle air conditioner of 2nd Embodiment. It is a graph which shows the relationship between the refrigerant | coolant flow volume and setting pressure in the evaporation pressure regulating valve of 2nd Embodiment.

(First embodiment)
A first embodiment of the present disclosure will be described with reference to FIGS. 1 to 10. In the present embodiment, the refrigeration cycle apparatus 10 according to the present disclosure is applied to a vehicle air conditioner 1 for an electric vehicle that obtains a driving force for vehicle traveling from a traveling electric motor. The refrigeration cycle apparatus 10 functions to cool or heat the air (blasted air) blown into the vehicle interior, which is the air-conditioning target space, in the vehicle air conditioner 1. Accordingly, the heat exchange target fluid of this embodiment is blown air.

Furthermore, the refrigeration cycle apparatus 10 of the present embodiment is a heating mode refrigerant circuit that heats the air and heats the interior of the vehicle, and dehumidifies that dehumidifies and heats the interior of the vehicle by reheating the air that has been cooled and dehumidified. The refrigerant circuit can be switched to a heating mode refrigerant circuit and a cooling mode refrigerant circuit that cools the vehicle interior by cooling the blown air.

In FIG. 1, the refrigerant flow in the refrigerant circuit in the heating mode is indicated by black arrows, the refrigerant flow in the refrigerant circuit in the dehumidifying and heating mode is indicated by hatched arrows, and the refrigerant flow in the refrigerant circuit in the cooling mode is further indicated. The flow is indicated by white arrows.

Further, in this refrigeration cycle apparatus 10, an HFC-based refrigerant (specifically, R134a) is adopted as the refrigerant, and a vapor compression subcritical refrigeration cycle in which the high-pressure side refrigerant pressure Pd does not exceed the critical pressure of the refrigerant. It is composed. Of course, an HFO refrigerant (for example, R1234yf) or the like may be adopted as the refrigerant. Furthermore, refrigeration oil for lubricating the compressor 11 is mixed in the refrigerant, and a part of the refrigeration oil circulates in the cycle together with the refrigerant.

Among the components of the refrigeration cycle apparatus 10, the compressor 11 is disposed in the vehicle bonnet, sucks the refrigerant in the refrigeration cycle apparatus 10, compresses and discharges it, and is a fixed capacity type with a fixed discharge capacity. It is comprised as an electric compressor which drives this compression mechanism with an electric motor. Specifically, various compression mechanisms such as a scroll type compression mechanism and a vane type compression mechanism can be employed as the compression mechanism.

The electric motor is one whose operation (number of rotations) is controlled by a control signal output from the air conditioning control device 40 described later, and any type of an AC motor and a DC motor may be adopted. And the refrigerant | coolant discharge capability of a compression mechanism is changed because the air-conditioning control apparatus 40 controls the rotation speed of an electric motor. Accordingly, in the present embodiment, the electric motor constitutes the discharge capacity changing unit of the compression mechanism.

The refrigerant inlet side of the indoor condenser 12 is connected to the discharge port side of the compressor 11. The indoor condenser 12 is disposed in a casing 31 of an indoor air conditioning unit 30 described later, and exchanges heat between the discharged refrigerant (high-pressure refrigerant) discharged from the compressor 11 and the blown air that has passed through the indoor evaporator 18 described later. And a heating heat exchanger (heat radiator) for heating the blown air.

The refrigerant outlet side of the indoor condenser 12 is connected to one refrigerant inlet / outlet of the first three-way joint 13a that branches the flow of the refrigerant flowing out of the indoor condenser 12 in the dehumidifying heating mode. Such a three-way joint may be formed by joining pipes having different pipe diameters, or may be formed by providing a plurality of refrigerant passages in a metal block or a resin block. The basic configuration of second to fourth three-way joints 13b to 13d described later is the same as that of the first three-way joint 13a.

A first refrigerant passage 14a that guides the refrigerant flowing out of the indoor condenser 12 to the refrigerant inlet side of the outdoor heat exchanger 16 is connected to another refrigerant inlet / outlet of the first three-way joint 13a. In addition, at another refrigerant inflow / outlet of the first three-way joint 13a, the refrigerant that has flowed out of the indoor condenser 12 is supplied to the inlet side (specifically, the second expansion valve 15b disposed in the third refrigerant passage 14c described later). Is connected to the second refrigerant passage 14b leading to one refrigerant inflow / outlet of the third three-way joint 13c.

In the first refrigerant passage 14a, a first expansion valve 15a is disposed as an outdoor unit decompression device that decompresses the refrigerant flowing out of the indoor condenser 12 during the heating mode and the dehumidifying heating mode. The first expansion valve 15a is a variable throttle mechanism that includes a valve body that can change the throttle opening degree and an electric actuator that includes a stepping motor that changes the throttle opening degree of the valve body. .

Furthermore, the first expansion valve 15a is configured as a variable throttle mechanism with a fully open function that functions as a simple refrigerant passage with almost no refrigerant decompression effect by fully opening the throttle opening. The operation of the first expansion valve 15a is controlled by a control signal (control pulse) output from the air conditioning control device 40.

The refrigerant inlet side of the outdoor heat exchanger 16 is connected to the outlet side of the first expansion valve 15a. The outdoor heat exchanger 16 is disposed on the vehicle front side in the vehicle bonnet, and exchanges heat between the refrigerant circulating inside and the air outside the vehicle (outside air) blown from a blower fan (not shown). The blower fan is an electric blower whose number of rotations (blowing capacity) is controlled by a control voltage output from the air conditioning control device 40.

One refrigerant inlet / outlet of the second three-way joint 13b is connected to the refrigerant outlet side of the outdoor heat exchanger 16. A third refrigerant passage 14c that guides the refrigerant flowing out of the outdoor heat exchanger 16 to the refrigerant inlet side of the indoor evaporator 18 is connected to another refrigerant inlet / outlet of the second three-way joint 13b. In addition, the refrigerant flowing out of the outdoor heat exchanger 16 is supplied to another refrigerant inflow / outlet of the second three-way joint 13b from the inlet side of the accumulator 20 (specifically, one refrigerant of the fourth three-way joint 13d). A fourth refrigerant passage 14d leading to the inflow / outlet is connected.

The third refrigerant passage 14c is connected to the check valve 17 that only allows the refrigerant to flow from the second three-way joint 13b side to the indoor evaporator 18 side, and the third three-way joint 13c to which the second refrigerant passage 14b described above is connected. In addition, in the dehumidifying heating mode and the cooling mode, the second expansion valve 15b serving as a decompression device that decompresses the refrigerant that flows out of the outdoor heat exchanger 16 and flows into the indoor evaporator 18 is provided with respect to the refrigerant flow. Arranged in order.

The basic configuration of the second expansion valve 15b is the same as that of the first expansion valve 15a. Furthermore, the second expansion valve 15b of the present embodiment not only has a fully-open function that fully opens the refrigerant passage from the outdoor heat exchanger 16 to the indoor evaporator 18 when the throttle opening is fully opened, but also fully closes the throttle opening. In this case, it is composed of a variable throttle mechanism with a fully closing function that closes the refrigerant passage.

Therefore, in the refrigeration cycle apparatus 10 of the present embodiment, the refrigerant circuit can be switched by closing the third refrigerant passage 14c with the second expansion valve 15b fully closed. In other words, the second expansion valve 15b functions as a refrigerant unit decompression device and also functions as a refrigerant circuit switching unit that switches a refrigerant circuit of the refrigerant circulating in the cycle.

The indoor evaporator 18 is disposed in the casing 31 of the indoor air conditioning unit 30 on the upstream side of the blower air flow of the indoor condenser 12, and in the cooling mode and the dehumidifying heating mode, the low-pressure refrigerant that circulates inside the indoor evaporator 18 12 is a heat exchanger for cooling (evaporator) that cools the blown air by causing heat exchange with the blown air before passing through 12 and evaporating the refrigerant to exhibit an endothermic effect.

The inlet side of the evaporation pressure adjusting valve 19 is connected to the refrigerant outlet side of the indoor evaporator 18. The evaporation pressure adjusting valve 19 sets the refrigerant evaporation pressure (refrigerant evaporation temperature) in the indoor evaporator 18 to be equal to or higher than a predetermined reference evaporation pressure (reference evaporation temperature) in order to suppress frost formation (frost) of the indoor evaporator 18. It fulfills the function of maintaining.

In this embodiment, R134a is used as the refrigerant, and the reference evaporation temperature is determined to be a value slightly higher than 0 ° C., so the reference evaporation pressure is a value slightly higher than 0.293 MPa. The detailed configuration of the evaporation pressure adjusting valve 19 will be described later.

The fourth three-way joint 13d to which the above-described fourth refrigerant passage 14d is connected is connected to the outlet side of the evaporation pressure adjusting valve 19. Furthermore, the inlet side of the accumulator 20 is connected to another refrigerant inlet / outlet of the fourth three-way joint 13d.

Also, a first on-off valve 21 for opening and closing the fourth refrigerant passage 14d is disposed in the fourth refrigerant passage 14d that connects the second three-way joint 13b and the fourth three-way joint 13d. The first on-off valve 21 is an electromagnetic valve whose operation is controlled by a control signal output from the air-conditioning control device 40, and functions as a refrigerant circuit switching unit.

Similarly, a second on-off valve 22 for opening and closing the second refrigerant passage 14b is disposed in the second refrigerant passage 14b connecting the first three-way joint 13a and the third three-way joint 13c. The basic configuration of the second on-off valve 22 is the same as that of the first on-off valve 21. Further, the second on-off valve 22 functions as a refrigerant circuit switching unit together with the second expansion valve 15 b and the first on-off valve 21.

The accumulator 20 is a gas-liquid separator that separates the gas-liquid of the refrigerant that has flowed into the accumulator and stores excess refrigerant in the cycle. The suction port side of the compressor 11 is connected to the gas-phase refrigerant outlet of the accumulator 20. Therefore, the accumulator 20 functions to prevent liquid phase refrigerant from being sucked into the compressor 11 and prevent liquid compression in the compressor 11.

Next, the detailed configuration of the evaporation pressure adjusting valve 19 will be described with reference to FIGS. The evaporation pressure adjusting valve 19 is constituted by a pure mechanical mechanism. Specifically, the evaporating pressure adjusting valve 19 has a body 91 configured by combining a plurality of metal members, and a cylindrical valve body portion 92, a refrigerant passage formed inside the body 91, A bellows 93, a spring 94 and the like are arranged.

The body 91 forms an outer shell of the evaporation pressure regulating valve 19 and is formed in a cylindrical shape. An inflow port 91a connected to the refrigerant outlet side of the indoor evaporator 18 is provided on one end side in the axial direction of the body 91 formed in a cylindrical shape, and connected to the inlet side of the accumulator 20 on the other end side in the axial direction. An outlet 91b is provided.

Furthermore, a cylinder portion 91c is formed on the downstream side of the refrigerant flow of the inlet 91a of the body 91. A cylindrical space is formed inside the cylinder portion 91c, and the cylindrical portion 92a of the cylindrical valve body portion 92 is fitted in the cylindrical space so as to be slidable in the axial direction. That is, the outer diameter size of the cylindrical portion 92a of the cylindrical valve body portion 92 and the inner diameter size of the cylinder portion 91c are in a dimensional relationship of the clearance fit.

As shown in FIGS. 2 to 4, the cylindrical valve body 92 is formed of a bottomed cylindrical (cup-shaped) metal member, and is disposed on the other axial end side (outlet 91b side). On the bottom surface is provided a flange 92b that extends perpendicular to the axial direction. The flange portion 92b is a portion that abuts on the most downstream end portion of the cylinder portion 91c and regulates the displacement of the cylindrical valve body portion 92. Furthermore, a plurality (six in this embodiment) of communication holes 92c are formed on the side surface of the cylindrical portion 92a of the cylindrical valve body portion 92 so as to communicate the inner peripheral side and the outer peripheral side thereof. For example, as shown in FIG. 2, the communication hole 92 c is a plurality of triangular openings arranged in the circumferential direction of the cylindrical valve body portion 92, and one side of each triangular opening is the same as that of the cylindrical valve body portion 92. It is provided on the circumference and is disposed closer to the inlet 91a side of the evaporation pressure regulating valve 19 than the other two sides of each triangular opening.

When the tubular valve body 92 is displaced toward one end in the axial direction (the inlet 91a side) and the flange 92b is in contact with the most downstream end of the cylinder 91c, the communication hole 92c is formed in the cylinder. It is blocked by the inner peripheral wall surface of 91c, and the communication between the inflow port 91a and the outflow port 91b is blocked. When the cylindrical valve body portion 92 is displaced from the other end side in the axial direction to increase the displacement L, the communication hole 92c is exposed from the cylinder portion 91c, and the outflow port 91b and the outflow port 91b pass through the communication hole 92c. Communicate through.

Furthermore, as the displacement amount L of the cylindrical valve body 92 increases, the area of the portion of the communication hole 92c exposed from the cylinder portion 91c increases. In the present embodiment, the area of the refrigerant passage in the evaporation pressure regulating valve 19 is changed by displacing the cylindrical valve body portion 92 in this way. That is, the cylinder part 91c and the cylindrical valve body part 92 of the present embodiment constitute a so-called slide valve.

The bellows 93 is a metal hollow cylindrical member formed to be extendable and contractible in the displacement direction of the cylindrical valve body portion 92 (the axial direction of the body 91), and is disposed on the downstream side of the refrigerant flow of the cylindrical valve body portion 92. Has been. Furthermore, the axial direction one end side of the bellows 93 is connected with the cylindrical valve body part 92, and the axial direction other end side of the bellows 93 is being fixed to the body 91 side.

A spring 94 is disposed in the internal space of the bellows 93. The spring 94 is constituted by a cylindrical coil spring that extends in the displacement direction of the cylindrical valve body 92, and urges the cylindrical valve body 92 together with the bellows 93 in the valve closing direction (direction toward the inflow port 91a). A load is applied. The load that the bellows 93 and the spring 94 urge against the cylindrical valve body 92 can be adjusted by the adjusting screw 94a.

Therefore, the cylindrical valve body 92 of the present embodiment includes the refrigerant pressure on the inlet 91a side (refrigerant evaporation pressure in the indoor evaporator 18), the refrigerant pressure on the outlet 91b side (the suction side refrigerant pressure of the compressor 11, that is, Refrigerant pressure in the accumulator 20) and further a load by the bellows 93 and the spring 94.

The tubular valve body 92 is displaced to a position where these loads are balanced, so that the refrigerant passage area in the evaporation pressure adjusting valve 19 is adjusted. More specifically, the balance of the load received by the tubular valve body portion 92 can be expressed by the following formula F1.
P1 * A1 + P2 * A2 = K * L + P2 * A1 + F0 (F1)
Here, P1 is the refrigerant pressure on the inlet 91a side, P2 is the refrigerant pressure on the outlet 91b side, A1 is the pressure receiving area of the tubular valve body 92, A2 is the pressure receiving area of the bellows 93, K is the bellows 93 and The total spring constant of the spring 94, L is the amount of displacement of the tubular valve body 92, and F0 is the initial load of the bellows 93 and spring 94 adjusted by the adjusting screw 94a.

Further, in the evaporation pressure adjusting valve 19 of the present embodiment, since A1≈A2, Equation F1 can be modified as Equation F2 below.
P1 = K / A1 × L + F0 / A1 (F2)
According to this mathematical formula F2, it can be seen that the refrigerant pressure P1 on the inlet 91a side increases as the displacement amount L increases. Further, as described above, as the displacement L increases, the refrigerant passage area in the evaporation pressure adjusting valve 19 increases, and the flow rate of refrigerant flowing through the indoor evaporator 18 also increases.

Therefore, the evaporation pressure adjusting valve 19 of the present embodiment increases the refrigerant pressure P1 on the inlet 91a side as the refrigerant flow rate flowing through the indoor evaporator 18 (the refrigerant flow rate flowing through the evaporation pressure adjusting valve 19) increases. It has a configuration to let you. That is, the evaporation pressure adjusting valve 19 of the present embodiment increases the displacement L in proportion to the increase of the refrigerant pressure P1 on the inlet 91a side, and adjusts the evaporation pressure with the increase of the refrigerant pressure P1 on the inlet 91a side. The refrigerant passage area in the valve 19 is increased. In this example, the refrigerant pressure P1 on the inlet 91a side corresponds to the refrigerant evaporation pressure Pe in the indoor evaporator 18.

Furthermore, as is apparent from the side view of FIG. 3, the plurality of communication holes 92c of the present embodiment are each formed in an isosceles triangle shape having a vertex on the outlet 91b side. That is, the communication hole 92c is formed in a shape that gradually decreases in the valve opening direction of the cylindrical valve body portion 92 (the direction toward the outflow port 91b).

In other words, the length in the circumferential direction LC of the communication hole 92c in the axial vertical cross section shown in FIG. 4 gradually increases in the valve closing direction of the cylindrical valve body 92 (the direction toward the inflow port 91a). It is formed into a shape. More specifically, in the present embodiment, the shape of the communication hole 92c is determined so that the displacement amount L of the cylindrical valve body 92 and the square root of the refrigerant passage area change in proportion.

For this reason, in the evaporation pressure regulating valve 19 of the present embodiment, the refrigerant accompanying the increase in the displacement amount L of the cylindrical valve body 92 shown by the thick solid line in FIG. 5 (that is, the rise in the refrigerant pressure P1 on the inlet 91a side). The increase in the passage area linearly increases the refrigerant passage area in proportion to the increase in the displacement amount L of the cylindrical valve body 92 shown by the thick broken line in FIG. 5 (hereinafter referred to as a comparative example). It is larger over the entire area than the degree. The evaporating pressure adjusting valve 19 has an inner refrigerant passage area that increases as the refrigerant evaporating pressure Pe in the indoor evaporator 18 increases. The degree of increase when the refrigerant passage area increases as the refrigerant evaporation pressure Pe increases is larger than the degree of increase when the refrigerant passage area increases linearly in proportion to the increase of the refrigerant evaporation pressure Pe (comparative example). Is also getting bigger. Specifically, as shown in FIG. 5, the degree of increase is set so that the refrigerant passage area becomes larger than the degree of increase when the displacement L is linearly increased with a tangential slope at the time of zero (comparative example). Is set.

Therefore, in the evaporation pressure regulating valve 19 of the present embodiment, as shown by the thick solid line in FIG. 6, the increase degree of the set pressure Pset accompanying the increase in the flow rate of the refrigerant flowing through the indoor evaporator 18 is indicated by the thick broken line in FIG. Than the degree of increase in the set pressure Pset of the comparative example shown. It becomes smaller over the entire area.

Note that the set pressure Pset of the present embodiment is that the evaporation pressure adjusting valve 19 in the fully opened state (the displacement amount L is the maximum displacement amount) uses the refrigerant evaporation pressure in the indoor evaporator 18 as the reference evaporation pressure. In order to maintain the above, the refrigerant pressure on the inlet 91a side (the refrigerant in the indoor evaporator 18) when the reduction of the refrigerant passage area is started (when the displacement of the tubular valve body 92 in the valve closing direction is started). Evaporative pressure).

More specifically, in the evaporating pressure adjusting valve 19, when the refrigeration cycle apparatus 10 is operated in the cooling mode or the dehumidifying heating mode, the displacement amount L of the cylindrical valve body portion 92 becomes the maximum displacement amount immediately after the operation is started. Become.

Thereafter, when the refrigerant pressure P2 on the outlet 91b side decreases as the rotational speed of the compressor 11 increases, the bellows 93 and the spring are adjusted so that the refrigerant pressure P1 on the inlet 91a side is maintained above the reference evaporation pressure. The cylindrical valve body 92 is displaced in the valve closing direction (direction toward the inflow port 91a) by the load of 94.

Then, the refrigerant pressure P1 on the inlet 91a side when the cylindrical valve body 92 starts to be displaced in the valve closing direction becomes the set pressure Pset. Further, the set pressure Pset increases as the flow rate of the refrigerant flowing through the indoor evaporator 18 increases, as shown in FIG.

Next, the indoor air conditioning unit 30 shown in FIG. 1 will be described. The indoor air conditioning unit 30 is for blowing out the blown air whose temperature has been adjusted by the refrigeration cycle apparatus 10 into the vehicle interior, and is disposed inside the instrument panel (instrument panel) at the forefront of the vehicle interior. Furthermore, the indoor air conditioning unit 30 is configured by housing a blower 32, the indoor evaporator 18, the indoor condenser 12, and the like in a casing 31 that forms an outer shell thereof.

The casing 31 forms an air passage for the blown air blown into the passenger compartment, and is formed of a resin (for example, polypropylene) having a certain degree of elasticity and excellent in strength. An inside / outside air switching device 33 as an inside / outside air switching unit that switches and introduces inside air (vehicle compartment air) and outside air (vehicle compartment outside air) into the casing 31 is arranged on the most upstream side of the blown air flow in the casing 31. ing.

The inside / outside air switching device 33 continuously adjusts the opening area of the inside air introduction port through which the inside air is introduced into the casing 31 and the outside air introduction port through which the outside air is introduced by the inside / outside air switching door, so that the air volume of the inside air and the air volume of the outside air are adjusted. The air volume ratio is continuously changed. The inside / outside air switching door is driven by an electric actuator for the inside / outside air switching door, and the operation of the electric actuator is controlled by a control signal output from the air conditioning control device 40.

A blower 32 that blows the air sucked through the inside / outside air switching device 33 toward the vehicle interior is disposed on the downstream side of the blowing air flow of the inside / outside air switching device 33. The blower 32 is an electric blower that drives a centrifugal multiblade fan (sirocco fan) with an electric motor, and the number of rotations (air flow rate) is controlled by a control voltage output from the air conditioning control device 40.

On the downstream side of the blower air flow of the blower 32, the indoor evaporator 18 and the indoor condenser 12 are arranged in this order with respect to the flow of the blown air. In other words, the indoor evaporator 18 is disposed on the upstream side of the blown air flow with respect to the indoor condenser 12. Further, in the casing 31, a cold air bypass passage 35 is formed in which the blown air that has passed through the indoor evaporator 18 bypasses the indoor condenser 12 and flows downstream.

On the downstream side of the blower air flow of the indoor evaporator 18 and on the upstream side of the blower air flow of the indoor condenser 12, the ratio of the amount of air passing through the indoor condenser 12 among the blown air after passing through the indoor evaporator 18. An air mix door 34 for adjusting the air pressure is disposed.

In addition, the blast air heated by the indoor condenser 12 and the blast air not heated by the indoor condenser 12 through the cold air bypass passage 35 are mixed on the downstream side of the blast air flow of the indoor condenser 12. A mixing space is provided. Furthermore, the opening hole which blows off the ventilation air (air-conditioning wind) mixed in the mixing space to the vehicle interior which is an air-conditioning object space is arrange | positioned in the most downstream part of the ventilation air flow of the casing 31. FIG.

Specifically, the opening hole includes a face opening hole that blows air-conditioned air toward the upper body of the passenger in the passenger compartment, a foot opening hole that blows air-conditioned air toward the feet of the passenger, and an inner surface of the front window glass of the vehicle. A defroster opening hole (both not shown) for blowing the conditioned air toward is provided. The air flow downstream of these face opening holes, foot opening holes, and defroster opening holes is connected to the face air outlet, foot air outlet, and defroster air outlet provided in the vehicle interior via ducts that form air passages, respectively. Neither is shown).

Therefore, the air mix door 34 adjusts the air volume ratio between the air volume that passes through the indoor condenser 12 and the air volume that passes through the cold air bypass passage 35, thereby adjusting the temperature of the conditioned air mixed in the mixing space. The temperature of the blast air (air conditioned air) blown out from each outlet to the vehicle interior is adjusted.

That is, the air mix door 34 constitutes a temperature adjustment unit that adjusts the temperature of the conditioned air blown into the vehicle interior. The air mix door 34 is driven by an electric actuator for driving the air mix door, and the operation of the electric actuator is controlled by a control signal output from the air conditioning control device 40.

Further, on the upstream side of the air flow of the face opening hole, foot opening hole, and defroster opening hole, a face door for adjusting the opening area of the face opening hole, a foot door for adjusting the opening area of the foot opening hole, and a defroster opening, respectively. A defroster door (both not shown) for adjusting the opening area of the hole is disposed.

These face doors, foot doors, and defroster doors constitute an opening hole mode switching unit that switches the opening hole mode, and are linked to an electric actuator for driving the outlet mode door via a link mechanism or the like. And rotated. The operation of this electric actuator is also controlled by a control signal output from the air conditioning control device 40.

Specifically, as the air outlet mode switched by the air outlet mode switching unit, a face mode in which the face air outlet is fully opened and air is blown out from the face air outlet toward the upper body of the passenger in the passenger compartment, the face air outlet and the foot air outlet The bi-level mode that opens both of the air outlets and blows air toward the upper body and feet of passengers in the passenger compartment, fully opens the foot outlet and opens the defroster outlet by a small opening, and mainly draws air from the foot outlet. There is a foot mode for blowing air, and a foot defroster mode for opening air from both the foot air outlet and the defroster air outlet by opening the foot air outlet and the defroster air outlet to the same extent.

Furthermore, when the occupant manually operates a blow mode switching switch provided on the operation panel 60, the defroster mode in which the defroster blowout port is fully opened and air is blown out from the defroster blowout port to the inner surface of the front windshield of the vehicle can be set.

Next, the electric control unit of this embodiment will be described with reference to FIG. The air conditioning control device 40 includes a known microcomputer including a CPU, a ROM, a RAM, and the like and peripheral circuits thereof. Then, various calculations and processes are performed based on the air conditioning control program stored in the ROM, and the compressor 11, the first expansion valve 15a, the second expansion valve 15b, and the first on-off valve connected to the output side thereof. 21, the operation of various air conditioning control devices such as the second on-off valve 22 and the blower 32 are controlled.

Further, on the input side of the air-conditioning control device 40, an inside air sensor 51 as an inside air temperature detector that detects a vehicle interior temperature (inside air temperature) Tr, and an outside air temperature detector that detects a vehicle outside temperature (outside air temperature) Tam. An outside air sensor 52, a solar radiation sensor 53 as a solar radiation amount detector for detecting the solar radiation amount As irradiated into the vehicle interior, a discharge temperature sensor 54 for detecting the refrigerant discharge temperature Td of the refrigerant discharged from the compressor 11, and an outlet of the indoor condenser 12 High pressure side pressure sensor 55 for detecting the side refrigerant pressure (high pressure side refrigerant pressure) Pd, the evaporator temperature sensor 56 for detecting the refrigerant evaporation temperature (evaporator temperature) Tefin in the indoor evaporator 18, and the outlet side refrigerant of the indoor evaporator 18 Air conditioning such as a low pressure side pressure sensor 57 that detects pressure (low pressure side refrigerant pressure) Pe, and a blown air temperature sensor 58 that detects a blown air temperature TAV blown from the mixed space into the vehicle interior. Detection signals of patronage groups of the sensor is input.

The high-pressure side refrigerant pressure Pd of the present embodiment is, for example, a high-pressure side refrigerant pressure of a cycle from the discharge port side of the compressor 11 to the inlet side of the first expansion valve 15a in the heating mode or the like, and in the cooling mode, It becomes the high pressure side refrigerant pressure of the cycle from the discharge port side of the compressor 11 to the inlet side of the second expansion valve 15b.

Further, the low-pressure side refrigerant pressure Pe of the present embodiment is a value corresponding to the actual refrigerant evaporation pressure in the indoor evaporator 18 in the cooling mode and the dehumidifying heating mode.

Moreover, although the evaporator temperature sensor 56 of this embodiment has detected the heat exchange fin temperature of the indoor evaporator 18, the temperature which detects the temperature of the other site | part of the indoor evaporator 18 as the evaporator temperature sensor 56 is detected. A detector may be employed, or a temperature detector that directly detects the temperature of the refrigerant itself flowing through the indoor evaporator 18 may be employed.

Moreover, in this embodiment, although the ventilation air temperature sensor which detects blowing air temperature TAV is provided, the value calculated based on evaporator temperature Tefin, discharge refrigerant temperature Td, etc. is employ | adopted as this blowing air temperature TAV. May be.

Furthermore, on the input side of the air conditioning control device 40, operation signals from various air conditioning operation switches provided on the operation panel 60 disposed in the vicinity of the instrument panel in the front of the vehicle interior are input. Specific examples of the various air conditioning operation switches provided on the operation panel 60 include an auto switch for setting or canceling the automatic control operation of the vehicle air conditioner 1, and a cooling switch (A / C switch), an air volume setting switch for manually setting the air volume of the blower 32, a temperature setting switch for setting the vehicle interior set temperature Tset, which is a target temperature in the vehicle interior, and a blow mode switching switch for manually setting the air discharge mode.

The air-conditioning control device 40 is configured integrally with a control unit that controls various air-conditioning control devices connected to the output side of the air-conditioning control device 40. The configuration (hardware and hardware) controls the operation of each air-conditioning control device. Software) constitutes a control unit that controls the operation of each air conditioning control device.

For example, in the present embodiment, the configuration for controlling the operation of the compressor 11 constitutes the discharge capacity control unit 40a, and the second expansion valve 15b, the first on-off valve 21 and the second on-off valve 22 constituting the refrigerant circuit switching unit. The configuration for controlling the operation of the refrigerant circuit constitutes the refrigerant circuit control unit 40b. Of course, the discharge capacity control unit, the refrigerant circuit control unit, and the like may be configured as a separate control device with respect to the air conditioning control device 40.

Next, the operation of the vehicle air conditioner 1 according to this embodiment having the above-described configuration will be described with reference to FIGS. The vehicle air conditioner 1 according to the present embodiment can switch the operation in the cooling mode, the heating mode, and the dehumidifying heating mode. The switching between these operation modes is performed by executing an air conditioning control program stored in the air conditioning control device 40 in advance.

FIG. 8 is a flowchart showing a control process as a main routine of the air conditioning control program. This control process is executed when the auto switch of the operation panel 60 is turned on. In addition, each control step of the flowchart shown to FIG. 8, FIG. 9 comprises the various function implementation | achievement part which the air-conditioning control apparatus 40 has.

First, in step S1, initialization such as initialization of flags and timers configured by the storage circuit of the air-conditioning control device 40 and initial positioning of the stepping motors constituting the various electric actuators described above is performed. It should be noted that in the initialization in step S1, some of the flags and the calculated values are read out from the values stored at the previous stop of the vehicle air conditioner or the end of the vehicle system.

Next, in step S2, detection signals from the sensor groups 51 to 58 for air conditioning control, operation signals from the operation panel 60, and the like are read. In subsequent step S3, based on the detection signal and operation signal read in step S2, a target blowing temperature TAO that is a target temperature of the blown air blown into the vehicle interior is calculated.

Specifically, the target blowing temperature TAO is calculated by the following formula F3.
TAO = Kset × Tset−Kr × Tr−Kam × Tam−Ks × As + C (F3)
Note that Tset is the vehicle interior set temperature set by the temperature setting switch, Tr is the vehicle interior temperature (inside air temperature) detected by the inside air sensor 51, Tam is the outside air temperature detected by the outside air sensor 52, and As is the solar radiation sensor 53. Is the amount of solar radiation detected by. Kset, Kr, Kam, Ks are control gains, and C is a correction constant.

Next, in step S4, the operation mode is determined. More specifically, in step S4, a subroutine shown in FIG. 9 is executed. First, in step S41, it is determined whether or not the cooling switch of the operation panel 60 is turned on. When it is determined in step S41 that the cooling switch is turned on (turned on), the process proceeds to step S42.

On the other hand, when it is determined in step S41 that the cooling switch is not turned on (turned off), the process proceeds to step S45, the operation mode is determined as the heating mode, and the process proceeds to step S5.

In step S42, it is determined whether or not a value (TAO-Tam) obtained by subtracting the outside air temperature Tam from the target blowing temperature TAO is lower than a predetermined reference cooling temperature α (α = 0 in the present embodiment). .

In step S42, if (TAO-Tam) <α, the process proceeds to step S43, the operation mode is determined to be the cooling mode, and the process returns to step S5. On the other hand, if (TAO−Tam) <α is not satisfied in step S42, the process proceeds to step S44, the operation mode is determined to be the dehumidifying heating mode, and the process returns to step S5.

In the subsequent step S5, the open / close state of the first and second open /

close valves

21 and 22 is determined according to the operation mode determined in step 4. In step S6, the opening degree of the air mix door 34 is determined according to the operation mode determined in step 4. Further, in step S7, the operating states of the first and

second expansion valves

15a and 15b are determined according to the operation mode determined in step 4.

More specifically, in steps S5 to S7, as shown in the chart of FIG. 10, the open / close state of the first and second on-off

valves

21 and 22, the opening of the air mix door 34, and the first and second The operating state of the

expansion valves

15a and 15b is determined. In subsequent step S8, the refrigerant discharge capacity of the compressor 11 is determined as described in detail in each operation mode described later.

In step S9, control signals or control voltages are output from the air conditioning control device 40 to the various air conditioning control devices so that the operating states of the various air conditioning control devices determined in steps S5 to S8 are obtained. In continuing step S10, it waits for control period (tau), and if progress of control period (tau) is determined, it will return to step S2.

In the vehicle air conditioner 1 of the present embodiment, the operation mode is determined as described above, and the operation in each operation mode is executed. The operation in each operation mode will be described below.

(A) Heating Mode In the heating mode, as shown in the chart of FIG. 10, the air conditioning control device 40 opens the first on-off valve 21, closes the second on-off valve 22, and exerts a pressure reducing action on the first expansion valve 15a. The second expansion valve 15b is fully closed.

Thereby, in the heating mode, as indicated by the black arrow in FIG. 1, the compressor 11 → the indoor condenser 12 → the first expansion valve 15 a → the outdoor heat exchanger 16 → (the first on-off valve 21 →) the accumulator 20 → A vapor compression refrigeration cycle in which refrigerant is circulated in the order of the compressor 11 is configured.

Further, with the configuration of this refrigerant circuit, as described in steps S6 to S8 above, the air conditioning control device 40 operates the various air conditioning control devices in the heating mode (control signals output to the various air conditioning control devices). To decide.

For example, for the control signal output to the electric actuator of the air mix door 34 determined in step S6, the air mix door 34 fully closes the cold air bypass passage 35, and the entire blown air after passing through the indoor evaporator 18 The flow rate is determined so as to pass through the air passage on the indoor condenser 12 side.

Further, regarding the control signal output to the first expansion valve 15a determined in step S7, the degree of supercooling of the refrigerant flowing into the first expansion valve 15a is such that the coefficient of performance (COP) of the cycle is substantially the maximum value. It is determined so as to approach the target subcooling degree determined to be.

Further, the control signal output to the electric motor of the compressor 11 determined in step S8 is determined as follows. First, the target condensing pressure PCO in the indoor condenser 12 is determined based on the target blowing temperature TAO with reference to a control map stored in the air conditioning control device 40 in advance.

Then, based on the deviation between the target condensation pressure PCO and the high-pressure side refrigerant pressure Pd detected by the high-pressure side pressure sensor 55, the feedback control method is used so that the high-pressure side refrigerant pressure Pd approaches the target condensation pressure PCO. A control signal output to the electric motor of the compressor 11 is determined.

Therefore, in the refrigeration cycle apparatus 10 in the heating mode, the high-pressure refrigerant discharged from the compressor 11 flows into the indoor condenser 12. The refrigerant flowing into the indoor condenser 12 exchanges heat with the blown air that has been blown from the blower 32 and passed through the indoor evaporator 18 to dissipate heat. Thereby, blowing air is heated.

Since the second on-off valve 22 is closed, the refrigerant flowing out of the indoor condenser 12 flows out from the first three-way joint 13a toward the first refrigerant passage 14a and is decompressed until it becomes a low-pressure refrigerant at the first expansion valve 15a. Is done. The low-pressure refrigerant decompressed by the first expansion valve 15a flows into the outdoor heat exchanger 16 and absorbs heat from the outside air blown from the blower fan.

The refrigerant flowing out of the outdoor heat exchanger 16 flows out from the second three-way joint 13b to the fourth refrigerant passage 14d side because the first on-off valve 21 is opened and the second expansion valve 15b is fully closed. It flows into the accumulator 20 and is separated into gas and liquid. The gas-phase refrigerant separated by the accumulator 20 is sucked from the suction side of the compressor 11 and compressed again by the compressor 11.

As described above, in the heating mode, the vehicle interior can be heated by blowing the air blown by the indoor condenser 12 into the vehicle interior.

(B) Dehumidification heating mode In the dehumidification heating mode, as shown in the chart of FIG. 10, the air conditioning control device 40 opens the first on-off valve 21, opens the second on-off valve 22, and restricts the first expansion valve 15a. And the second expansion valve 15b is in the throttle state.

As a result, in the second dehumidifying and heating mode, as indicated by the hatched arrow in FIG. 1, the compressor 11 → the indoor condenser 12 → the first expansion valve 15a → the outdoor heat exchanger 16 → (the first on-off valve 21 →) The refrigerant is circulated in the order of accumulator 20 → compressor 11, and compressor 11 → indoor condenser 12 → (second on-off valve 22 →) second expansion valve 15 b → indoor evaporator 18 → evaporation pressure regulating valve 19 → A vapor compression refrigeration cycle in which refrigerant is circulated in the order of accumulator 20 → compressor 11 is configured.

That is, in the dehumidifying and heating mode, the refrigerant flowing out from the indoor condenser 12 flows in the order of the first expansion valve 15a → the outdoor heat exchanger 16 → the compressor 11, and the second expansion valve 15b → the indoor evaporator 18 → the evaporation pressure adjustment. The refrigerant circuit is switched in parallel in the order of the valve 19 → the compressor 11. Therefore, the refrigerant circuit in the dehumidifying heating mode corresponds to the second refrigerant circuit described in the claims.

Furthermore, with the configuration of this refrigerant circuit, the air conditioning control device 40 determines the operating state of various air conditioning control devices in the dehumidifying heating mode, as described in steps S6 to S8 above.

For example, for the control signal output to the electric actuator of the air mix door 34 determined in step S6, the air mix door 34 fully closes the cold air bypass passage 35 and passes through the indoor evaporator 18 as in the heating mode. The total flow rate of the subsequent blown air is determined so as to pass through the air passage on the indoor condenser 12 side.

As for the control signal output to the first expansion valve 15a determined in step S7, as in the heating mode, the degree of supercooling of the refrigerant flowing into the first expansion valve 15a is the coefficient of performance (COP) of the cycle. ) Is determined so as to approach the target degree of subcooling determined to be substantially the maximum value.

On the other hand, the control signal output to the second expansion valve 15b is determined so that the flow rate of the refrigerant flowing through the indoor evaporator 18 becomes an appropriate flow rate. Specifically, the throttle opening degree of the second expansion valve 15b is adjusted so that the superheat degree of the refrigerant on the outlet side of the indoor evaporator 18 becomes a predetermined reference superheat degree (for example, 5 ° C.).

Further, the control signal output to the electric motor of the compressor 11 determined in step S8 is determined in the same manner as in the heating mode.

Accordingly, in the refrigeration cycle apparatus 10 in the dehumidifying and heating mode, the high-pressure refrigerant discharged from the compressor 11 flows into the indoor condenser 12 and is cooled by the indoor evaporator 18 to be dehumidified and exchanged heat. To dissipate heat. Thereby, blowing air is heated.

The flow of the refrigerant flowing out of the indoor condenser 12 is branched at the first three-way joint 13a because the second on-off valve 22 is open. One refrigerant branched by the first three-way joint 13a flows out to the first refrigerant passage 14a side and is depressurized until it becomes a low-pressure refrigerant by the first expansion valve 15a. The low-pressure refrigerant decompressed by the first expansion valve 15a flows into the outdoor heat exchanger 16 and absorbs heat from the outside air blown from the blower fan.

On the other hand, the other refrigerant branched by the first three-way joint 13a flows out to the second refrigerant passage 14b side. The refrigerant that has flowed out to the second refrigerant passage 14b side does not flow out to the outdoor heat exchanger 16 side due to the action of the check valve 17, and the second expansion is performed via the second on-off valve 22 and the third three-way joint 13c. It flows into the valve 15b.

The refrigerant that has flowed into the second expansion valve 15b is depressurized until it becomes a low-pressure refrigerant. The low-pressure refrigerant decompressed by the second expansion valve 15 b flows into the indoor evaporator 18, absorbs heat from the blown air blown from the blower 32, and evaporates. Thereby, blowing air is cooled.

Furthermore, the refrigerant that has flowed out of the indoor evaporator 18 is decompressed by the evaporation pressure adjusting valve 19, and becomes the same pressure as the refrigerant that has flowed out of the outdoor heat exchanger 16. The refrigerant that has flowed out of the evaporating pressure adjusting valve 19 flows into the fourth three-way joint 13d and merges with the refrigerant that has flowed out of the outdoor heat exchanger 16. The refrigerant merged at the fourth three-way joint 13d flows from the accumulator 20 to the suction side of the compressor 11 and is compressed again by the compressor 11.

As described above, in the dehumidifying heating mode, the vehicle interior can be heated by heating the blown air that has been cooled and dehumidified by the indoor evaporator 18 and blown out into the vehicle interior. .

At this time, the refrigerant evaporation temperature in the indoor evaporator 18 is maintained at or above the reference evaporation temperature (in this embodiment, a value higher than 0 ° C.) by the action of the evaporation pressure adjusting valve 19. Can be suppressed.

Furthermore, since the refrigerant evaporation temperature in the outdoor heat exchanger 16 can be lower than the refrigerant evaporation temperature in the indoor evaporator 18, the temperature difference between the refrigerant evaporation temperature in the outdoor heat exchanger 16 and the outside air temperature is increased. The amount of heat absorbed by the refrigerant in the outdoor heat exchanger 16 can be increased.

As a result, the heating capacity of the blown air in the indoor condenser 12 is increased as compared with the cycle configuration in which the refrigerant evaporation temperature in the outdoor heat exchanger 16 becomes equal to or higher than the reference evaporation temperature similarly to the refrigerant evaporation temperature in the indoor evaporator 18. Can be made.

(C) Cooling mode In the cooling mode, as shown in the chart of FIG. 10, the air conditioning control device 40 closes the first on-off valve 21, closes the second on-off valve 22, and fully opens the first expansion valve 15a. The second expansion valve 15b is brought into a throttled state.

Thereby, in the cooling mode, as indicated by the white arrow in FIG. 1, the compressor 11 → the indoor condenser 12 → (first expansion valve 15 a →) outdoor heat exchanger 16 → (check valve 17 →) second A vapor compression refrigeration cycle in which the refrigerant is circulated in the order of the expansion valve 15b → the indoor evaporator 18 → the evaporation pressure adjusting valve 19 → the accumulator 20 → the compressor 11 is configured. Accordingly, the cooling mode refrigerant circuit corresponds to the first refrigerant circuit recited in the claims.

Furthermore, with the configuration of this refrigerant circuit, as described in the above steps S6 to S8, the air conditioning control device 40 determines the operating state of various air conditioning control devices in the cooling mode.

For example, for the control signal output to the electric actuator of the air mix door 34 determined in step S6, the air mix door 34 fully opens the cold air bypass passage 35, and the total flow rate of the blown air after passing through the indoor evaporator 18 Is determined to pass through the cold air bypass passage 35. In the cooling mode, the opening degree of the air mix door 34 may be controlled so that the blown air temperature TAV approaches the target blowing temperature TAO.

Further, regarding the control signal output to the second expansion valve 15b determined in step S7, the degree of supercooling of the refrigerant flowing into the second expansion valve 15b indicates that the coefficient of performance (COP) of the cycle is substantially the maximum value. It is determined so as to approach the target subcooling degree determined to be.

Further, the control signal output to the electric motor of the compressor 11 determined in step S8 is determined as follows. First, the target evaporation pressure PEO in the indoor evaporator 18 is determined based on the target outlet temperature TAO with reference to a control map stored in advance in the air conditioning controller 40.

More specifically, in this control map, the target evaporation pressure PEO is determined to decrease as the target blowing temperature TAO decreases. Further, the target evaporation pressure PEO is determined to be equal to or higher than the minimum target evaporation pressure (for example, 0.315 Mpa, that is, the refrigerant evaporation temperature corresponds to 2 ° C.) determined so as to be able to suppress frost formation in the indoor evaporator 18. The Therefore, in this embodiment, control step S8 comprises the target evaporation pressure determination part described in the claim.

Based on the deviation between the target evaporation pressure PEO and the low-pressure refrigerant pressure Pe detected by the low-pressure sensor 57, the low-pressure refrigerant pressure Pe approaches the target evaporation pressure PEO using a feedback control method. A control signal output to the electric motor of the compressor 11 is determined.

Here, the target outlet temperature TAO described above is a value determined in order to maintain the vehicle interior temperature at the vehicle interior set temperature Tset corresponding to the desired temperature of the passenger. Therefore, in the refrigeration cycle apparatus 10 that cools the blown air by the indoor evaporator 18 as in the cooling mode of the present embodiment, the cooling heat load of the cycle increases as the target blowing temperature TAO decreases.

In other words, as the target blowing temperature TAO decreases, the cooling capacity of the blown air required for the indoor evaporator 18 increases. That is, the target evaporation pressure determination unit of the present embodiment determines to decrease the target evaporation pressure PEO as the cooling capacity of the blown air required for the indoor evaporator 18 increases.

Therefore, in the refrigeration cycle apparatus 10 in the cooling mode, the high-pressure refrigerant discharged from the compressor 11 flows into the indoor condenser 12. At this time, since the air mix door 34 fully closes the air passage on the indoor condenser 12 side, the refrigerant flowing into the indoor condenser 12 flows out of the indoor condenser 12 with almost no heat exchange with the blown air. .

Since the second on-off valve 22 is closed, the refrigerant that has flowed out of the indoor condenser 12 flows out from the first three-way joint 13a toward the first refrigerant passage 14a and flows into the first expansion valve 15a. At this time, since the first expansion valve 15a is fully opened, the refrigerant flowing out of the indoor condenser 12 flows into the outdoor heat exchanger 16 without being depressurized by the first expansion valve 15a.

The refrigerant flowing into the outdoor heat exchanger 16 dissipates heat to the outside air blown from the blower fan in the outdoor heat exchanger 16. Since the first on-off valve 21 is closed, the refrigerant that has flowed out of the outdoor heat exchanger 16 flows into the third refrigerant passage 14c via the second three-way joint 13b, and the low-pressure refrigerant is separated from the refrigerant at the second expansion valve 15b. The pressure is reduced until

The low-pressure refrigerant decompressed by the second expansion valve 15 b flows into the indoor evaporator 18, absorbs heat from the blown air blown from the blower 32, and evaporates. Thereby, blowing air is cooled. The refrigerant flowing out of the indoor evaporator 18 flows into the accumulator 20 through the evaporation pressure adjusting valve 19 and is separated into gas and liquid. The gas-phase refrigerant separated by the accumulator 20 is sucked from the suction side of the compressor 11 and compressed again by the compressor 11.

As described above, in the cooling mode, the vehicle interior can be cooled by blowing the blown air cooled by the indoor evaporator 18 into the vehicle interior.

Therefore, according to the vehicle air conditioner 1 of the present embodiment, appropriate air conditioning in the passenger compartment can be realized by switching the operation of the heating mode, the dehumidifying heating mode, and the cooling mode.

Here, as in the refrigeration cycle apparatus 10 of the present embodiment, in the configuration in which the target evaporation pressure PEO is decreased in accordance with the increase in the cooling capacity of the blown air required for the indoor evaporator 18 in the cooling mode, the indoor evaporation is performed. The refrigerant discharge capacity (rotation speed) of the compressor 11 is increased with an increase in the cooling capacity of the blown air required for the compressor 18.

However, in the refrigeration cycle apparatus including the evaporation pressure adjusting valve 19, if the refrigerant discharge capacity of the compressor 11 is increased and the refrigerant flow rate flowing through the indoor evaporator 18 is increased as described with reference to FIG. Since the set pressure Pset of the regulating valve 19 increases, the refrigerant evaporation pressure (low-pressure side refrigerant pressure Pe) in the indoor evaporator 18 also increases.

At this time, if the set pressure Pset exceeds the target evaporation pressure PEO, the refrigerant evaporation pressure Pe cannot be lowered until the target evaporation pressure PEO is reached even if the refrigerant discharge capacity of the compressor 11 is increased. So-called control interference occurs.

When such control interference occurs, the rotational speed of the compressor 11 is unnecessarily increased in order to bring the refrigerant evaporation pressure Pe in the indoor evaporator 18 close to the target evaporation pressure PEO. Will increase. Furthermore, an unnecessary increase in the rotational speed of the compressor 11 adversely affects the durable life of the compressor 11.

On the other hand, in the refrigeration cycle apparatus 10 of this embodiment, as shown in FIG. 5, the degree of increase in the refrigerant passage area with respect to the increase in the displacement L of the cylindrical valve body 92 is compared as the evaporation pressure adjusting valve 19. The one that is larger than the example is adopted. As a result, as shown in FIG. 6, the degree of increase in the set pressure Pset when the flow rate of the refrigerant flowing through the indoor evaporator 18 is increased is reduced so that the set pressure Pset becomes lower than the target evaporation pressure PEO. Yes.

Then, the operation of the compressor 11 is controlled so that the refrigerant evaporation pressure Pe approaches the target evaporation pressure PEO which is the higher value of the set pressure Pset and the target evaporation pressure PEO. Therefore, the above-described control interference does not occur in the refrigeration cycle apparatus 10 of the present embodiment. As a result, the cooling capacity required for the indoor evaporator 18 can be exhibited without unnecessarily increasing the power consumption of the compressor 11.

That is, in the refrigeration cycle apparatus 10 of the present embodiment, an unnecessary increase in power consumption of the compressor 11 is suppressed by changing the rising characteristic of the set pressure Pset with respect to the increase in the refrigerant flow rate in the evaporation pressure adjusting valve 19. Yes. Moreover, in this embodiment, it can also be expressed that the refrigerating cycle apparatus provided with the evaporation pressure regulating valve 19 comprised so that suppression of the unnecessary increase of the power consumption of the compressor 11 can be suppressed is disclosed.

Further, in the evaporation pressure adjusting valve 19 of the present embodiment, a cylinder valve is formed by the cylinder portion 91c and the cylindrical valve body portion 92, and the shape of the communication hole 92c formed in the side surface of the cylindrical valve body portion 92 is opened. The shape is gradually reduced toward the valve direction. Therefore, the degree of increase in the refrigerant passage area as shown by the solid line in FIG. 5 can be easily realized.

(Second Embodiment)
Although 1st Embodiment demonstrated the example which employ | adopted the evaporation pressure adjustment valve 19 from which the setting pressure Pset becomes a value lower than the target evaporation pressure PEO even if the refrigerant | coolant flow volume which distribute | circulates the indoor evaporator 18 increased, When there is a restriction on the size of the evaporation pressure adjusting valve 19 or the like, the set pressure Pset may exceed the target evaporation pressure PEO when the flow rate of the refrigerant flowing through the indoor evaporator 18 increases.

Therefore, in the present embodiment, the evaporating pressure adjusting valve 19 linearly increases the refrigerant passage area in proportion to the increase in the displacement amount L of the cylindrical valve body 92 (corresponding to a comparative example of the first embodiment). Further, the determination of the operating state of the compressor 11 in the control step S8 in the cooling mode is changed with respect to the first embodiment.

Specifically, in the control step S8 in the cooling mode of the present embodiment, the operation mode is determined in step S81 as shown in the flowchart of FIG. If it is determined in step S81 that the operation mode is the heating mode, the process proceeds to step S82, and the refrigerant discharge capacity (operating state) of the compressor 11 is determined as in the heating mode of the first embodiment. Then, the process proceeds to step S9.

Further, when it is determined in step S81 that the operation mode is the dehumidifying heating mode, the process proceeds to step S83, and the refrigerant discharge capacity (operation) of the compressor 11 is performed as in the dehumidifying heating mode of the first embodiment. State) is determined, and the process proceeds to step S9. Further, when it is determined in step S81 that the operation mode is the cooling mode, the process proceeds to step S84.

In step S84, the target evaporation pressure PEO is determined as in the first embodiment, and in subsequent step S85, it is determined whether or not the refrigerant evaporation pressure Pe is higher than the target evaporation pressure PEO. When it is determined in step S85 that the refrigerant evaporation pressure Pe is higher than the target evaporation pressure PEO, the process proceeds to step S86, where it is determined that the refrigerant evaporation pressure Pe is not higher than the target evaporation pressure PEO. If YES, go to step S87.

In step S86, it is determined whether or not the evaporation pressure adjusting valve 19 is operating. If it is determined in step S86 that the evaporation pressure adjusting valve 19 is operating, the process proceeds to step S87, the number of rotations of the compressor 11 is decreased by a predetermined amount, and the process proceeds to step S9. On the other hand, if it is determined in step S86 that the evaporation pressure adjusting valve 19 is not in operation, the process proceeds to step S88, the rotation speed of the compressor 11 is increased by a predetermined amount, and the process proceeds to step S9. move on.

Here, “the evaporating pressure adjusting valve 19 is operating” means that in FIG. 12, the area determined by the flow rate of the refrigerant flowing through the indoor evaporator 18 and the refrigerant evaporating pressure Pe is in the area indicated by hatching. Means state. More specifically, this means that the evaporation pressure adjusting valve 19 reduces the refrigerant passage area below the maximum value in order to maintain the refrigerant evaporation pressure Pe in the indoor evaporator 18 at or above the reference evaporation pressure. .

Further, the determination in the control step S86 can be realized by storing the relationship between the refrigerant flow rate and the set pressure Pset in the evaporation pressure adjusting valve 19 as shown in FIG. In this embodiment, since the evaporation pressure regulating valve 19 corresponding to the comparative example of the first embodiment is adopted, the set pressure Pset shown by the thick solid line in FIG. 12 is the set pressure shown by the thick broken line in FIG. It is equivalent to Pset.

Other configurations and operations are the same as those in the first embodiment. Therefore, in the vehicle air conditioner 1 of the present embodiment, air conditioning in the vehicle compartment can be realized by switching the operation in the heating mode, the dehumidifying heating mode, and the cooling mode, as in the first embodiment.

Furthermore, in the cooling mode of the present embodiment, the operation of the compressor 11 is controlled so that the refrigerant evaporation pressure Pe approaches the higher one of the target evaporation pressure PEO and the set pressure Pset. Unnecessary increase can be suppressed.

This will be explained in more detail. In the present embodiment, it is determined in control step S85 that the refrigerant evaporation pressure Pe in the indoor evaporator 18 is higher than the target evaporation pressure PEO, and in control step S86. When it is determined that the evaporation pressure adjusting valve 19 is not in operation, the rotational speed (refrigerant discharge capacity) of the compressor 11 is increased in control step S88.

According to this, when the target evaporation pressure PEO is higher than the set pressure Pset, the operation of the compressor 11 can be controlled so that the refrigerant evaporation pressure Pe approaches the target evaporation pressure PEO. Therefore, the cooling capacity required for the indoor evaporator 18 can be exhibited without unnecessarily increasing the power consumption of the compressor 11.

On the other hand, when it is determined in the control step S85 that the refrigerant evaporation pressure Pe in the indoor evaporator 18 is higher than the target evaporation pressure PEO, and the evaporation pressure adjusting valve 19 is activated in the control step S86. When the determination is made, the rotational speed (refrigerant discharge capacity) of the compressor 11 is decreased in the control step S87.

Here, as described above, the evaporating pressure adjusting valve 19 functions to maintain the refrigerant evaporating pressure Pe in the indoor evaporator 18 at or above the reference evaporating pressure. Therefore, under the operating conditions in which the refrigerant evaporation pressure Pe is higher than the target evaporation pressure PEO and the evaporation pressure adjustment valve 19 is operating, the set pressure Pset of the evaporation pressure adjustment valve 19 is higher than the target evaporation pressure PEO. It will be.

Under such operating conditions, although the refrigerant evaporation pressure Pe is increased by reducing the rotational speed of the compressor 11 as in the present embodiment, the flow rate of the refrigerant flowing through the indoor evaporator 18 is decreased, The set pressure Pset can be reduced. Furthermore, the refrigerant evaporating pressure Pe can be brought close to the set pressure Pset in a state where the evaporating pressure adjusting valve 19 is not operated (a state where the refrigerant passage area is maximized).

That is, in the cooling mode of the present embodiment, when the set pressure Pset is higher than the target evaporation pressure PEO, the evaporation pressure adjustment valve 19 is deactivated, that is, the evaporation pressure adjustment valve 19 is The operation of the compressor 11 is controlled so as to suppress the reduction of the internal refrigerant passage area, and the refrigerant evaporation pressure Pe is brought close to the set pressure Pset.

Therefore, it is possible to avoid control interference caused by trying to bring the refrigerant evaporating pressure Pe closer to the target evaporating pressure PEO, and it is possible to easily suppress an unnecessary increase in power consumption of the compressor 11.

(Other embodiments)
The present disclosure is not limited to the above-described embodiment, and can be variously modified as follows without departing from the spirit of the present disclosure.

(1) In each of the above-described embodiments, the example in which the refrigeration cycle apparatus 10 of the present disclosure is applied to the vehicle air conditioner 1 mounted on an electric vehicle has been described, but the application of the present disclosure is not limited thereto. For example, the driving force for driving the vehicle may be applied to a vehicle air conditioner mounted on a normal vehicle that obtains from the internal combustion engine (engine), or the driving force for driving from both the driving electric motor and the internal combustion engine. You may apply to the vehicle air conditioner mounted in the hybrid vehicle which obtains.

When applied to a vehicle having an internal combustion engine, a heater core that heats the blown air using the cooling water of the internal combustion engine as a heat source may be provided as an auxiliary heating device for the blown air. Furthermore, the refrigeration cycle apparatus 10 of the present disclosure is not limited to a vehicle, and may be applied to a stationary air conditioner or the like.

(2) In each of the embodiments described above, the refrigeration cycle apparatus 10 that can be switched to the refrigerant circuit in the heating mode, the dehumidifying heating mode, and the cooling mode has been described, but at least the configuration similar to the cooling mode of the above-described embodiment, If it is a refrigeration cycle apparatus that operates in the same manner, the power consumption suppression effect of the compressor 11 can be obtained.

Further, in the refrigeration cycle apparatus 10 described in each of the above-described embodiments, the first and second on-off

valves

21 and 22 are closed and switched to the refrigerant circuit similar to that in the cooling mode, and further according to the target outlet temperature TAO. You may make it operate | move in the auxiliary | assistant dehumidification heating mode which performs dehumidification heating of a vehicle interior by changing the aperture opening degree of the 1st expansion valve 15a and the 2nd expansion valve 15b.

Specifically, in the auxiliary dehumidifying and heating mode, the throttle opening of the first expansion valve 15a is decreased and the throttle opening of the second expansion valve 15b is increased as the target blowing temperature TAO increases. Thereby, the outdoor heat exchanger 16 may be switched from a state of functioning as a radiator to a state of functioning as an evaporator, and the heating capacity of the blown air in the indoor condenser 12 may be changed.

(3) In each of the above-described embodiments, the example in which the operation of the compressor 11 is controlled so that the low-pressure refrigerant pressure Pe approaches the target evaporation pressure PEO in the cooling mode has been described. Instead of this, the operation of the compressor 11 may be controlled using the detected value of the refrigerant temperature.

For example, the target evaporation temperature TEO in the indoor evaporator 18 is determined based on the target blowing temperature TAO with reference to a control map stored in the air conditioning control device 40 in advance, and the refrigerant evaporation detected by the evaporator temperature sensor 56 is determined. The operation of the compressor may be controlled so that the temperature (evaporator temperature) Tefin approaches the target evaporation temperature TEO. In addition, what is necessary is just to determine target evaporation temperature TEO so that it may fall with the fall of target blowing temperature TAO.

In the control step S86 of the second embodiment described above, the relationship between the refrigerant flow rate and the set pressure Pset in the evaporating pressure adjusting valve 19 is stored in advance in the air conditioning control device 40, whereby the evaporating pressure adjusting valve 19 is activated. However, the determination as to whether or not the evaporation pressure adjusting valve 19 is operating is not limited to this.

For example, an outlet-side low pressure sensor for detecting the outlet-side refrigerant pressure Pso of the evaporation pressure adjusting valve 19 is provided, and a pressure reference (Pe−Peo) between the low-pressure side refrigerant pressure Pe and the outlet-side refrigerant pressure Pso is a predetermined reference. When the pressure difference is greater than or equal to the pressure difference, it may be determined that the evaporation pressure adjustment valve 19 is operating.

(4) In each of the above-described embodiments, the example in which the blown air is heated by exchanging heat between the high-pressure refrigerant and the blown air in the indoor condenser 12 during the heating mode and the dehumidifying heating mode has been described. Instead of the condenser 12, for example, a heat medium circulation circuit for circulating the heat medium is provided, and a water-refrigerant heat exchanger for exchanging heat between the high-pressure refrigerant and the heat medium in the heat medium circulation circuit and water-refrigerant heat exchange are provided. A heat exchanger or the like for heating that heats the blown air by exchanging heat between the heat medium heated by the vessel and the blown air may be arranged.

A water-refrigerant heat exchanger may be adopted as a heat radiator, and high-pressure refrigerant and blown air may be indirectly heat-exchanged via a heat medium. Furthermore, when applied to a vehicle having an internal combustion engine, the heat medium circulation circuit may be circulated using cooling water of the internal combustion engine as a heat medium. Moreover, in an electric vehicle, you may make it distribute | circulate a heat-medium circulation circuit by using the cooling water which cools a battery and an electric equipment as a heat medium.

(5) In each of the above-described embodiments, a variable capacity compressor that obtains a rotational driving force from an internal combustion engine or the like, which is an example in which an electric compressor is employed as the compressor 11, may be employed. Further, in each of the above-described embodiments, the example in which the evaporation pressure adjusting valve 19 in which each constituent member is formed of metal has been described. However, for example, a cylindrical valve body portion 92 formed of resin is used. Alternatively, instead of the bellows 93, one having a bellophram formed of a bottomed cylindrical (cup-shaped) rubber may be employed.

(6) In each of the above-described embodiments, the example in which the target evaporation pressure determining unit is configured in the control step S8 has been described. Of course, the target evaporation pressure determining unit may be configured in another control step. For example, in the control step S3, the target evaporation pressure PEO may be determined together with the target blowing temperature TAO. In this case, the target evaporation pressure determination unit is configured by the control step S3.

(7) In each of the above-described embodiments, the example in which each operation mode is switched by executing the air conditioning control program has been described. However, the switching of each operation mode is not limited to this. For example, an operation mode setting switch for setting each operation mode may be provided on the operation panel, and the heating mode, the cooling mode, and the dehumidifying heating mode may be switched according to an operation signal of the operation mode setting switch.

Claims

A compressor (11) for compressing and discharging the refrigerant;
An outdoor heat exchanger (16) for exchanging heat between the refrigerant discharged from the compressor (11) and the outside air;
A decompression device (15b) for decompressing the refrigerant flowing out of the outdoor heat exchanger (16);
An evaporator (18) for exchanging heat between the low-pressure refrigerant decompressed by the decompression device (15b) and the heat exchange target fluid, and evaporating the low-pressure refrigerant;
An evaporation pressure adjusting valve (19) for adjusting the refrigerant evaporation pressure (Pe) in the evaporator (18) to be equal to or higher than a predetermined reference evaporation pressure;
A target evaporation pressure determining unit (S8) for determining a target evaporation pressure (PEO) in the evaporator (18);
A discharge capacity control section (40a) for controlling the operation of the compressor (11),
The target evaporation pressure determining unit (S8) determines the target evaporation pressure (PEO) to decrease with an increase in the cooling capacity of the heat exchange target fluid required for the evaporator (18). And
The evaporating pressure adjusting valve (19) is configured such that the set pressure (Pset) increases with an increase in the flow rate of the refrigerant flowing through the evaporator (18).
When the discharge capacity control unit (40a) controls the operation of the compressor (11), the refrigerant evaporating pressure approaches the higher one of the target evaporating pressure (PEO) and the set pressure (Pset). Regulated refrigeration cycle equipment.
The evaporating pressure adjusting valve (19) is configured such that the internal refrigerant passage area increases as the refrigerant evaporating pressure (Pe) increases.
The degree of increase when the refrigerant passage area increases with an increase in the refrigerant evaporation pressure (Pe) is that when the refrigerant passage area increases linearly in proportion to the increase in the refrigerant evaporation pressure (Pe). The refrigeration cycle apparatus according to claim 1, wherein the refrigeration cycle apparatus is larger than the degree of increase.
The evaporating pressure adjusting valve (19) includes a cylinder portion (91c) formed in a cylindrical shape, and a cylindrical valve formed in a bottomed cylindrical shape and slidably disposed inside the cylinder portion (91c). Having a body (92),
A communication hole (92c) for communicating the inner peripheral side and the outer peripheral side is formed on the side surface of the cylindrical portion (92a) of the cylindrical valve body portion (92),
The shape of the communication hole (92c) is formed in a shape that gradually decreases in a direction in which the cylindrical valve body (92) is displaced toward the side of increasing the refrigerant passage area. The refrigeration cycle apparatus described.
The discharge capacity control section (40a) controls the operation of the compressor (11) so as to prevent the evaporation pressure regulating valve (19) from decreasing the internal refrigerant passage area. Item 4. The refrigeration cycle apparatus according to any one of Items 1 to 3.
A radiator (12) for exchanging heat between the high-pressure refrigerant discharged from the compressor (11) and the fluid for heat exchange;
The refrigeration cycle apparatus according to any one of claims 1 to 4, further comprising: an outdoor unit decompression device (15a) that decompresses the refrigerant flowing into the outdoor heat exchanger (16).
A refrigerant circuit switching unit (21, 22) for switching the refrigerant circuit of the cycle;
The radiator (12) exchanges heat between the high-pressure refrigerant and the heat exchange target fluid after passing through the evaporator (18).
The refrigerant circuit switching unit (21, 22) includes at least the compressor (11) → the outdoor heat exchanger (16) → the pressure reducing device (15b) → the evaporator (18) → the evaporation pressure adjusting valve (19 ) → the first refrigerant circuit for circulating the refrigerant in the order of the compressor (11), and the compressor (11) → the radiator (12) → the pressure reducing device (15b) → the evaporator (18) → the evaporation The refrigerant is circulated in the order of the pressure regulating valve (19) → the compressor (11), and the compressor (11) → the radiator (12) → the outdoor unit pressure reducing device (15a) → the outdoor heat exchanger ( The refrigeration cycle apparatus according to claim 5, wherein the second refrigerant circuit for circulating the refrigerant in the order of 16) → the compressor (11) is switchable.
The evaporating pressure adjusting valve (19) has an increased internal refrigerant passage area as the refrigerant evaporating pressure (Pe) increases.
The degree of increase when the refrigerant passage area increases as the refrigerant evaporating pressure (Pe) increases is proportional to the increase in the refrigerant evaporating pressure (Pe), and the slope of the tangent at the time when the displacement amount is zero. The refrigeration cycle apparatus according to claim 1, wherein the refrigeration cycle apparatus is larger than a degree of increase when the refrigerant passage area increases linearly.
The evaporating pressure adjusting valve (19) includes a cylinder part (91c) formed in a cylindrical shape, and a cylindrical valve formed on the bottomed cylinder and slidably disposed inside the cylinder part (91c). Having a body (92),
A communication hole (92c) that connects the inner peripheral side and the outer peripheral side is formed on the side surface of the cylindrical portion of the cylindrical valve body portion (92),
The shape of the communication hole (92c) is a shape in which the area of the refrigerant passage is changed by the relative displacement of the cylindrical valve body portion (92) and the cylinder portion (91c) in the axial direction. Refrigeration cycle equipment.
The communication hole (92c) is a plurality of triangular openings arranged in the circumferential direction of the cylindrical valve body (92), and one side of each triangular opening is the same as that of the cylindrical valve body (92). The refrigeration cycle apparatus according to claim 8, wherein the refrigeration cycle apparatus is provided on a circumference and disposed closer to the inlet (91a) of the evaporation pressure regulating valve (19) than the other two sides of each triangular opening.