JP2010048498A - Refrigerating cycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain high air-conditioning performance without complicating device constitution and a control system in a refrigerating cycle. <P>SOLUTION: The refrigerating cycle includes: a variable displacement compressor 1; a condenser 2 cooling a refrigerant discharged from the compressor 1; an expansion device 3 allowing the refrigerant delivered from the condenser 2, to pass through a valve part inside to throttle and expand the refrigerant and to lead it out, and autonomously adjusting the valve opening so that the downstream side pressure of the led-out refrigerant is a set pressure; an evaporator 4 evaporating the refrigerant led out of the expansion device 3, to exchange heat with the outside, and delivering the refrigerant toward the compressor 1; and a control valve 6 controlling the flow rate of the refrigerant led into a crankcase from a discharge chamber of the compressor 1 so that differential pressure between predetermined two points in the refrigerating cycle or the flow rate is constant, to change the discharge capacity of the compressor 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a refrigeration cycle suitable for an automotive air conditioner.

  In general, an air conditioner for an automobile compresses the refrigerant flowing through the refrigeration cycle and discharges it as a high-temperature / high-pressure gas refrigerant, a condenser that condenses the gas refrigerant, and adiabatic expansion of the condensed liquid refrigerant. And an expansion device that converts the refrigerant into a low-temperature and low-pressure refrigerant, an evaporator that exchanges heat with the air in the vehicle interior by evaporating the refrigerant, and the like. The refrigerant evaporated in the evaporator is returned to the compressor and circulates in the refrigeration cycle.

  As this compressor, a variable capacity compressor (also simply referred to as “compressor”) capable of varying the refrigerant discharge capacity is used so that a constant cooling capacity is maintained regardless of the engine speed. In this compressor, a piston for compression is connected to a swing plate attached to a rotary shaft that is driven to rotate by an engine, and the discharge amount of the refrigerant is changed by changing the stroke of the piston by changing the angle of the swing plate. adjust. The angle of the swing plate can be continuously changed by introducing a part of the discharged refrigerant into the sealed crank chamber and changing the balance of pressure applied to both surfaces of the piston. The pressure in the crank chamber (hereinafter referred to as “crank pressure”) Pc is a variable displacement compressor control valve (simply provided between the discharge chamber and the crank chamber of the compressor or between the crank chamber and the suction chamber). It is also controlled by “control valve”).

  By the way, such a compressor can be a heavy load on the engine. For this reason, it is necessary to reduce the load torque of the compressor at the time of high load in which the engine power is to be directed to the driving force of the vehicle, for example, when the vehicle is suddenly accelerated or when the vehicle is traveling uphill. Conventionally, a variable capacity compressor in which an electromagnetic clutch that transmits or cuts off the driving force of the engine is provided at one end of the rotating shaft so that the load torque can be temporarily cut has been employed. However, in recent years, a so-called clutchless type compressor in which an engine and a rotating shaft are directly connected without using an electromagnetic clutch is becoming mainstream for reasons such as cost reduction.

  This clutchless compressor includes, for example, an external control including a valve unit that controls opening and closing of a passage that leads from the discharge chamber to the crank chamber, and a solenoid that generates an electromagnetic force that causes the valve unit to act in a closing direction. A control valve of the type is used. In this control valve, when energization to the solenoid is interrupted, the valve portion is fully opened, and the crank pressure Pc can be kept high. As a result, the swing plate is substantially perpendicular to the rotation axis, and the compressor can be shifted to the minimum capacity operation. That is, even if the engine and the rotating shaft are directly connected, the discharge capacity can be substantially reduced to zero, thereby minimizing the load torque. As such a control valve, for example, a so-called Ps sensing valve that performs capacity control by adjusting the valve opening based on the suction pressure Ps of the compressor, a differential pressure (Pd-Ps) between the discharge pressure Pd and the suction pressure Ps. A so-called Pd-Ps valve that performs capacity control based on the above, a so-called flow control valve that controls the discharge capacity of the compressor itself to be a set value, and the like are employed (see, for example, Patent Documents 1 to 3).

  Since the Ps sensing valve directly controls the suction pressure Ps proportional to the refrigerant temperature on the outlet side of the evaporator, there is an advantage that it is easy to adjust the dehumidification temperature of the air exchanged in the evaporator. That is, generally, a fan and a heater for blowing are respectively arranged before and after the evaporator, and the air sent by the fan is cooled by the latent heat of evaporation when passing through the evaporator. The cooled air is heated to an appropriate temperature by a heater and sent into the passenger compartment. In order to dry the air, it is only necessary to lower the temperature of the refrigerant passing through the evaporator to remove a lot of moisture in the air. Conversely, in order to maintain a certain level of humidity, the refrigerant temperature is set slightly higher. do it. There is an advantage that the adjustment of the refrigerant temperature and the adjustment of the humidity of the air to be heat-exchanged can be stably performed. However, since the control is based on the suction pressure Ps, there may be a lack of responsiveness in controlling the discharge capacity.

On the other hand, since the Pd-Ps valve performs capacity control based on the magnitude of the discharge pressure Pd itself, it has excellent responsiveness for changing the discharge capacity. Further, since the differential pressure (Pd−Ps) between the discharge pressure Pd and the suction pressure Ps reflects the load torque of the compressor, there is an advantage that it is easy to adjust the load torque according to the engine load. Since the flow rate control valve directly changes the discharge capacity itself, there is an advantage that the capacity control response is excellent.
JP 2005-214059 A JP 2001-132650 A JP 2006-17035 A

  However, on the contrary, since the Pd-Ps valve and the flow rate control valve do not control the suction pressure Ps, if the suction pressure Ps changes with the differential pressure control or the flow rate control, the air blowing temperature at the outlet of the evaporator May become unstable and the intended dehumidifying performance may not be obtained. In some cases, the suction pressure Ps may be excessively reduced to cause excessive cooling. For this reason, the opening degree of each control valve is normally controlled so that the outlet temperature of the evaporator is not fed back and the suction pressure Ps does not decrease too much. That is, while each control valve is based on its original control method, the functions of other control valves must be supplemented depending on the situation, and the control method and the configuration of the apparatus are complicated in that respect. there were.

  This invention is made | formed in view of such a problem, and it aims at maintaining the air-conditioning performance highly, without complicating the apparatus structure and control system in a refrigerating cycle.

  In order to solve the above-described problem, a refrigeration cycle according to an aspect of the present invention is a refrigeration cycle that constitutes an air conditioner. The refrigeration cycle compresses the refrigerant sucked from the suction chamber and discharges the refrigerant from the discharge chamber. A variable capacity compressor that changes in accordance with the crank pressure in the crank chamber, an external heat exchanger that cools the refrigerant discharged from the variable capacity compressor, and an internal valve portion for the refrigerant sent from the external heat exchanger. An expansion device in which the valve opening degree is autonomously adjusted so that the downstream pressure of the derived refrigerant becomes a set pressure, and the refrigerant derived from the expansion device And the heat exchange with the outside, the evaporator that sends the refrigerant to the variable capacity compressor, and the differential pressure or flow rate between two predetermined points of the refrigeration cycle is constant By controlling the flow rate of refrigerant introduced into the crank chamber from the discharge chamber of the variable displacement compressor, and a control valve for changing the discharge capacity of the compressor, the.

  The “control valve” referred to here may be a constant differential pressure valve that controls the differential pressure between two points to be a set differential pressure, such as the differential pressure between the discharge pressure and the suction pressure of the variable capacity compressor. Alternatively, it may be a flow rate control valve that controls the flow rate of the refrigerant derived from the refrigerant outlet of the variable capacity compressor to be a set flow rate. In the latter case, the valve opening may be adjusted autonomously so that the flow rate of the refrigerant becomes the set flow rate. Alternatively, by fixing the refrigerant passage cross section at a predetermined position between the outlet of the variable capacity compressor and the discharge chamber, by controlling so that the differential pressure between the outlet pressure and the discharge chamber pressure becomes the set differential pressure, Control may be performed so that the flow rate of the refrigerant derived from the refrigerant outlet of the variable capacity compressor becomes a set flow rate.

  According to this aspect, since the valve opening is autonomously adjusted so that the downstream pressure of the expansion device becomes the set pressure, the refrigerant pressure in the evaporator is appropriately set by appropriately setting the set pressure. The desired dehumidifying performance by the evaporator can be obtained. On the other hand, since the discharge capacity of the variable capacity compressor can be directly controlled by the control valve, the capacity control response can be kept good. As a result, the air conditioning performance can be maintained high without complicating the device configuration and the control method.

  According to the present invention, the air conditioning performance can be maintained high without complicating the apparatus configuration and control method in the refrigeration cycle.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, for the sake of convenience, the positional relationship between the structures may be expressed as upper and lower with reference to the illustrated state.

[First Embodiment]
FIG. 1 is a system configuration diagram showing a refrigeration cycle according to the first embodiment.

  This refrigeration cycle constitutes a vehicular air conditioner, a variable capacity compressor (hereinafter simply referred to as “compressor”) 1 that compresses the refrigerant circulating in the refrigeration cycle, and condenses and cools the compressed refrigerant. A condenser 2 (corresponding to an “external heat exchanger”), an expansion device 3 that squeezes and expands the condensed refrigerant into a mist form, and an evaporator 4 that evaporates the expanded refrigerant are provided. A blower fan 5 and a heater (not shown) are respectively arranged before and after the evaporator 4, and the air sent by the fan 5 is cooled by latent heat of evaporation when passing through the evaporator 4. The cooled air is heated to an appropriate temperature by a heater and sent into the passenger compartment.

  The compressor 1 introduces and compresses refrigerant gas introduced into the suction chamber from the evaporator 4 side into the cylinder, and discharges high-temperature and high-pressure refrigerant from the discharge chamber to the condenser 2 side. A part of the discharged refrigerant is introduced into the crank chamber 54 via a variable capacity compressor control valve (hereinafter simply referred to as “control valve”) 6 and used for capacity control of the compressor 1. The control valve 6 is configured as a solenoid-driven electromagnetic valve, and a control unit (not shown) drives a drive circuit to control energization of the drive circuit.

FIG. 2 is a cross-sectional view illustrating the configuration of the compressor.
The compressor 1 includes, as its housing, a cylinder block 101 in which a plurality of cylinders 52 are formed, a front housing 102 joined to the front end side thereof, and a rear housing 104 joined to the rear end side thereof via a valve plate 103. And. A crank chamber 54 and a cylinder 52 are defined in an internal space surrounded by the cylinder block 101 and the front housing 102. The rear housing 104 has a suction chamber 51, a discharge chamber 53, and a valve storage chamber 55 defined in the inner space. The rear housing 104 is also provided with a refrigerant inlet 56 that introduces refrigerant into the suction chamber 51 from the evaporator 4 side, and a refrigerant outlet 57 that leads the discharged refrigerant from the discharge chamber 53 to the condenser 2 side.

  A rotation shaft 106 is disposed in the crank chamber 54 so as to penetrate the center thereof. The rotating shaft 106 is rotatably supported by a bearing 107 provided on the cylinder block 101 and a bearing 108 provided on the front housing 102. A lug plate 109 is fixed to the rotary shaft 106, and a swing plate 111 (corresponding to a “swing body”) is supported via a support arm 110 protruding from the lug plate 109. The swing plate 111 can tilt with respect to the axis of the rotary shaft 106, and is connected via a shoe 114 to a piston 112 slidably disposed in the plurality of cylinders 52. The rotating shaft 106 has a front end portion extending through the front housing 102 and extending to the outside, and a bracket 117 is screwed to the tip portion. Further, a lip seal 115 as a shaft seal member is provided so as to seal a gap between the front end portion of the rotating shaft 106 and the front housing 102 from the outside. The lip seal 115 is in sliding contact with the peripheral surface of the rotating shaft 106 and prevents leakage of refrigerant gas along the peripheral surface.

  A pulley 118 that transmits driving force from the engine is rotatably supported on the front end portion of the front housing 102 via a bearing 119. The pulley 118 transmits the driving force of the engine to the rotating shaft 106 via the bracket 117.

  The suction chamber 51 of the rear housing 104 communicates with the cylinder 52 via a suction relief valve 121 provided on the valve plate 103 and also communicates with the evaporator 4 via a refrigerant inlet 56. The discharge chamber 53 communicates with the cylinder 52 via a discharge relief valve (not shown) provided on the valve plate 103 and also communicates with the condenser 2 via a refrigerant outlet 57. The valve housing chamber 55 protrudes on the opposite side of the rear housing 104 from the cylinder block 101 and communicates with the discharge chamber 53 and the crank chamber 54, respectively.

  The swing plate 111 of the compressor 1 has an angle of the load of the springs 125 and 126 urging the swing plate 111 in the crank chamber 54 and the load due to the pressure applied to both surfaces of the piston 112 connected to the swing plate 111. Etc. are held in a balanced position. The angle of the oscillating plate 111 of the compressor 1 is changed continuously by introducing a part of the refrigerant discharged into the crank chamber 54 to change the crank pressure Pc and changing the balance of pressure applied to both surfaces of the piston 112. Can be changed. The refrigerant discharge capacity is adjusted by changing the stroke of the piston 112 by changing the angle of the swing plate 111. The pressure in the crank chamber 54 is controlled by the control valve 6.

  In a refrigerant passage (not shown) that connects the crank chamber 54 and the suction chamber 51, an orifice having a fixed cross-sectional area is provided, and a predetermined minimum flow rate of refrigerant flows from the crank chamber 54 to the suction chamber 51. The internal circulation of the refrigerant in the compressor 1 is ensured. In the refrigerant passage between the discharge chamber 53 of the compressor 1 and the condenser 2, a check valve (not shown) that allows the refrigerant to flow in one direction may be provided.

  Returning to FIG. 1, the expansion device 3 includes a so-called constant pressure expansion valve. The liquid refrigerant introduced from the condenser 2 side is expanded by being throttled by passing through an internal valve portion, and is then on the evaporator 4 side. To derive. The opening degree of the expansion device 3 is adjusted autonomously so that the downstream side pressure becomes a set pressure set from the outside. The refrigerant that has passed through the evaporator 4 is returned to the compressor 1 and compressed again. The valve opening degree of the control valve 6 and the expansion device 3 is controlled by a control unit (not shown). That is, the control unit includes a CPU that executes various arithmetic processes, a ROM that stores various control programs, a RAM that is used as a work area for data storage and program execution, an input / output interface, and the like. The control unit determines the set flow rate of the refrigerant flowing through the refrigeration cycle based on predetermined external information detected by various sensors such as the engine speed, the temperature inside and outside the vehicle interior, the temperature of the air blown from the evaporator 4, and the like. The energization of the control valve 6 is controlled so that a solenoid force that maintains the set flow rate is obtained. The control unit also determines a set value (set pressure) of the downstream pressure of the expansion device 3 based on predetermined external information, and performs energization control to the expansion device 3 so that the set pressure is maintained. By setting the set pressure, the pressure of the low-pressure refrigerant flowing through the evaporator 4 is adjusted.

FIG. 3 is a cross-sectional view showing the configuration of the control valve. 4 is an enlarged view of the upper half of the control valve shown in FIG.
The control valve 6 is configured as a flow rate control valve that controls the flow rate of the refrigerant introduced from the discharge chamber 53 to the crank chamber 54 so that the flow rate of the refrigerant derived from the compressor 1 is maintained at a set flow rate.

  As shown in FIG. 3, the control valve 6 is configured by integrally assembling a valve body 8 having a main valve and a sub-valve therein, and a solenoid 9 that opens and closes each valve of the valve body 8. A connector 90 is detachably connected to the control valve 6. The control valve 6 has a bottomed stepped cylindrical body 10. An inlet port 71 that communicates with the discharge chamber 53 is provided at the side of the body 10, and an outlet port 72 that communicates with the outlet of the compressor 1 is provided at the upper end opening. A communication port 73 that communicates with the crank chamber 54 is provided between the body 10 and the solenoid 9.

  As shown in FIG. 4, a refrigerant passage (corresponding to a “first refrigerant passage”) that connects the inlet port 71 and the outlet port 72 extends in the axial direction in the upper portion of the body 10. A valve hole 15 is formed in the middle part of the valve. A tapered surface whose diameter is increased upward is formed at the opening end of the valve hole 15 on the outlet port 72 side, and the valve seat 16 is formed by the tapered surface. On the other hand, a bottomed stepped cylindrical valve body 18 (corresponding to a “main valve body”) is detachably disposed so as to face the valve seat 16 from the outlet port 72 side. The valve body 18 and the valve seat 16 constitute a main valve. The valve body 18 has a conical side surface whose diameter is reduced downward in the lower half of the valve body 18, and is attached to and detached from the valve seat 16 on the side surface to open and close the main valve. A lower end portion of the valve body 18 extends downward to form a valve seat forming portion 19.

  A bottomed stepped cylindrical spring receiving member 11 is fitted into the upper end opening of the body 10 with the bottom facing up. The step portion of the spring receiving member 11 is formed with a plurality of communication holes communicating between the inside and the outside, and the outlet port 72 and the outlet of the compressor 1 are communicated with each other through the communication holes. The upper end opening of the valve body 18 is slidably inserted into and guided by the upper half of the spring receiving member 11. A space surrounded by the spring receiving member 11 and the valve body 18 is a damper chamber 76, and refrigerant can enter and exit through a small hole 77 provided at the center of the bottom of the spring receiving member 11. Between the spring receiving member 11 and the valve body 18 in the damper chamber 76, a spring 13 for biasing the valve body 18 in the valve closing direction is interposed.

  The discharged refrigerant led out from the discharge chamber 53 is introduced into the control valve 6 through the inlet port 71, and part of the refrigerant passes through the main valve and is led out from the outlet port 72. This refrigerant is led out from the outlet of the compressor 1 to the downstream side. As the discharge refrigerant passes through the main valve in this way, the discharge pressure Pd is slightly reduced from the discharge chamber pressure Pdh of the discharge chamber 53 to be output to the condenser 2 as the outlet pressure Pdl of the compressor 1. become. In the following description, the discharge chamber pressure Pdh and the outlet pressure Pdl may be collectively referred to as the discharge pressure Pd without particular distinction.

  On the other hand, the inside of the lower part of the body 10 is gradually reduced in diameter, and a guide hole 20 is formed at the center of the bottom. A cylindrical valve element 22 (corresponding to a “sub-valve element”) is inserted so as to penetrate the guide hole 20 and is supported so as to be slidable in the axial direction. The inlet port 71 and the communication port 73 communicate with each other through the guide hole 20. However, since the V ring 23 as a seal member is interposed between the bottom portion of the body 10 and the valve body 22, the valve body 22. Leakage of the refrigerant transmitted along the outer peripheral surface of the is prevented. A bottomed cylindrical stopper 24 is press-fitted directly above the V-ring 23 at the bottom of the body 10 to restrict displacement of the V-ring 23 in the axial direction. The stopper 24 is inserted through the upper part of the valve body 22 from below and through the valve seat forming portion 19 of the valve body 18 from above. A communication hole 78 that communicates the inside and the outside is formed in the side portion of the stopper 24, and a strainer 79 is fitted so as to cover the communication hole 78. The communication hole 78 communicates with the inlet port 71.

  The valve body 22 has a bottomed cylindrical shape, and a communication hole 25 that communicates the inside and the outside is provided in a side portion near the bottom. The inside of the valve body 22 forms a valve hole 26, and the upper end thereof opens and closes the auxiliary valve by being attached to and detached from a valve seat 27 formed on the lower surface of the valve seat forming portion 19. That is, the valve body 18 described above also functions as a movable valve seat, and the valve body 22 and the valve seat 27 constitute a secondary valve. The auxiliary valve is positioned corresponding to the communication hole 78, and when the auxiliary valve is opened, the refrigerant discharged from the inlet port 71 communicates via the communication hole 78, the auxiliary valve, the valve hole 26, and the communication hole 25. Derived from port 73. The lower end portion of the valve body 22 is disposed in the pressure chamber 28 that communicates with the crank chamber 54 via the communication port 73, and the valve body 22 is placed in the valve opening direction between the lower end portion and the body 10. An urging spring 29 is interposed.

  A part of the discharged refrigerant introduced through the inlet port 71 is reduced to the crank pressure Pc by passing through the auxiliary valve, led to the pressure chamber 28, and led out from the communication port 73. This refrigerant is introduced into the crank chamber 54 and used for controlling the discharge capacity of the compressor 1.

  Returning to FIG. 3, the solenoid 9 is magnetized by a case 31 that also functions as a yoke, a core 32 that is fixed in the case 31, a plunger 33 that is disposed to face the core 32 in the axial direction, and a current supplied from the outside. And an electromagnetic coil 34 for generating a circuit. The outer diameter of the upper end portion of the core 32 is increased, and the upper end portion of the case 31 is crimped and joined. The lower end portion of the body 10 is press-fitted into the upper end opening portion of the core 32, whereby the valve body 8 and the solenoid 9 are assembled.

  The core 32 is provided with an insertion hole 35 penetrating the center in the axial direction, and a shaft 36 for transmitting a solenoid force to the valve body 22 is inserted therethrough. A ring-shaped bearing member 38 is press-fitted into the upper end portion of the core 32, and the upper end portion of the shaft 36 is slidably supported by the bearing member 38. The crank pressure Pc in the pressure chamber 28 can be introduced into the solenoid 9 through a minute gap between the shaft 36 and the bearing member 38. The shaft 36 supports the valve body 22 from below by its upper end surface.

  Further, a bottomed sleeve 39 having a closed lower end is externally inserted into the core 32. In the bottomed sleeve 39, the plunger 33 is disposed below the core 32 so as to be able to advance and retract in the axial direction. A spring receiving member 40 is disposed at the bottom of the bottomed sleeve 39. The plunger 33 has a cylindrical shape and is press-fitted into the lower half of the shaft 36. Between the plunger 33 and the spring receiving member 40, a spring 41 that biases the plunger 33 in the closing direction of the sub valve (the opening direction of the main valve) is interposed. Further, a spring 45 that urges the plunger 33 in the valve opening direction (the valve closing direction of the main valve) is interposed between the core 32 and the plunger 33. Since the spring load by the spring 29 and the spring 45 is set to be larger than the spring load by the spring 41, the sub-valve is held in a fully opened state when the solenoid 9 is not energized. A bobbin 37 is extrapolated to the bottomed sleeve 39, and an electromagnetic coil 34 is wound around the bobbin 37.

  An insertion hole 61 is provided in the center of the bottom of the case 31, and the lower end of the bottomed sleeve 39 is exposed through the insertion hole 61. A pair of terminal lead-out portions 62 (only one is shown in the figure) and a pair of mated portions 63 (only one is shown in the figure) extend downward from the bottom of the bobbin 37, respectively. It penetrates the bottom. A conductive terminal 64 is embedded in the terminal lead-out portion 62. One end portion of the conductive terminal 64 is connected to the end portion of the electromagnetic coil 34, and the other end portion is exposed downward from the terminal lead-out portion 62. The fitted portion 63 is provided with a locking hole 65 for fixing the connector 90. A collar 66 is disposed at the bottom of the case 31 so as to be interposed between the bobbin 37 and the case 31. The collar 66 is made of a magnetic member and constitutes the bottom of the solenoid 9 and constitutes a magnetic circuit together with the case 31.

  The connector 90 is configured by providing connection terminals 94 inside a connector housing 92. The connector housing 92 is made of a bottomed stepped cylindrical resin material having corrosion resistance, and the lower half of the connection terminal 94 is exposed to the outside in an airtight manner. A claw portion 96 (corresponding to a “fitting portion”) protruding inward is integrally formed in the vicinity of the upper end opening of the connector housing 92. The connector housing 92 is fixed to the solenoid 9 by fitting the claw portion 96 into the locking hole 65 of the fitting portion 63 described above. An O-ring 97 (corresponding to a “seal member”) is fitted on the outer peripheral surface of the opening end of the connector housing 92.

  The control valve unit and the connector 90 constitute a control valve unit. This control valve unit is assembled by attaching the O-ring 97 to the connector housing 92 to form the connector 90 and then attaching the connector 90 to the solenoid 9. The control valve unit assembled in this way is inserted into the valve accommodating chamber 55 of the compressor 1 shown in FIG. As shown in the figure, the O-ring 97 is disposed on the opening side of the connection portion between the control valve 6 and the connector 90, so that the external atmosphere is prevented from entering the valve housing chamber 55.

  In the configuration of the control valve 6 described above, the valve seat 27 has a tapered surface, and the valve body 22 is attached to and detached from the valve seat 27 at the outer peripheral edge of the front end opening portion. The effect of the pressure Pc is substantially canceled. Therefore, when the sub-valve is closed while the energization control of the solenoid 9 is performed, a force in the valve opening direction corresponding to the solenoid force acts on the valve body 18.

Next, basic operations of the control valve 6 and the compressor 1 will be described.
In the control valve 6, when the solenoid 9 is in a non-energized state, the valve element 18 is seated on the valve seat 16 by the biasing force of the spring 13, and the main valve is closed. On the other hand, due to the resultant force of the springs 29, 41, 45, the valve body 22 is integrated with the shaft 36 and operates in the valve opening direction, and is separated from the valve seat 27 and is fully opened. In this state, when the rotating shaft 106 of the compressor 1 shown in FIG. 1 is rotated by driving the vehicle engine, the swing plate 111 performs swinging motion, and the piston 112 coupled thereto reciprocates. As a result, the refrigerant introduced into the suction chamber 51 is sucked into the cylinder 52 and compressed, and the compressed refrigerant is discharged into the discharge chamber 53. At this time, since the main valve is in the fully closed state, the discharged refrigerant passes through the fully opened sub valve and is introduced into the pressure chamber 28 and further introduced into the crank chamber 54 through the communication port 73. As a result, since the crank pressure Pc is increased, the compressor 1 performs the minimum capacity operation.

  When a predetermined control current is supplied to the solenoid 9, the plunger 33 is attracted to the core 32, so that the valve element 22 balances the force in the valve opening direction due to the resultant force of the spring and the solenoid force in the valve closing direction. It is held at the position to do. At this time, since the valve body 22 is momentarily seated on the valve body 18 in the closed state and the sub-valve is fully closed, the introduction of the refrigerant into the crank chamber 54 is interrupted, and the crank pressure Pc decreases, The compressor 1 immediately shifts to the maximum capacity operation. As a result, the discharge pressure Pd increases rapidly and the valve body 18 is lifted against the urging force of the spring 13, and the main valve is opened by the lift amount corresponding to the flow rate of the refrigerant. In addition, the valve body 18 as the movable valve seat is thereby separated from the valve body 22 and the sub-valve is opened, so that the refrigerant flow rate according to the relative position of the two valve bodies is transferred to the crank chamber 54. As a result, the compressor 1 is kept in an operating state with a predetermined capacity.

  Here, when the rotational speed of the vehicle engine is increased and the discharge pressure Pd is increased, the flow rate of the refrigerant discharged from the discharge chamber 53 is increased, and the valve body 18 is further lifted accordingly, and the valve opening degree of the main valve is increased. In order to increase the flow rate, the flow rate of the refrigerant discharged from the compressor 1 tends to increase. However, when the relative distance from the valve body 22, that is, the opening degree of the sub-valve, is further increased by the lift of the valve body 18, the refrigerant flow rate introduced into the crank chamber 54 increases, and the crank pressure Pc increases. As a result, the compressor 1 is controlled to reduce the refrigerant discharge flow rate. Conversely, when the rotational speed of the vehicle engine decreases, the refrigerant flow rate discharged from the discharge chamber 53 decreases, the refrigerant flow rate introduced into the crank chamber 54 also decreases, and the crank pressure Pc decreases. As a result, the compressor 1 is controlled to increase the refrigerant discharge flow rate. Thus, since the control valve 6 performs control so that the change in the flow rate of the discharged refrigerant becomes small even when the engine speed fluctuates and the flow rate of the discharged refrigerant changes, the flow rate of the discharged refrigerant from the compressor 1 Is controlled to be constant. The set flow rate of the discharged refrigerant can be changed according to the current value supplied to the solenoid 9. The control unit determines the set flow rate based on external information and performs energization control to the solenoid 9.

FIG. 5 is a cross-sectional view showing the configuration of the expansion device.
The expansion device according to the present embodiment squeezes and expands the refrigerant introduced from the upstream side and leads it to the downstream side, and controls the flow rate of the refrigerant so that the refrigerant pressure on the downstream side is maintained at the set pressure. Consists of valves. This expansion device is disposed so as to partition a body having a refrigerant passage formed therein, an upstream high-pressure refrigerant passage and a downstream low-pressure refrigerant passage in the body, and squeeze and expand the refrigerant introduced from the upstream side. The first valve section that is led to the downstream side, the intermediate pressure chamber that is filled with an intermediate pressure that is equal to or higher than the set pressure, and the first valve that senses the intermediate pressure so that the intermediate pressure becomes a preset reference pressure. A second pressure part that is provided in a pressure sensing part that generates a force in the opening / closing direction of the part, a pressure regulation passage that communicates the intermediate pressure chamber and the low-pressure refrigerant passage, and that generates a differential pressure across it by opening and closing; A solenoid that generates a solenoid force so that the differential pressure across the valve portion becomes a set differential pressure corresponding to the amount of supply current, and changes the set pressure by changing the set differential pressure.

  That is, the expansion device 3 is configured by assembling an expansion valve 131 configured as a constant pressure expansion valve and an adjustment valve 132 for adjusting the set pressure of the expansion valve 131. The expansion valve 131 includes a body 140 in which a valve portion is provided. A power element 142 (corresponding to a “pressure-sensitive part”) that opens and closes the valve part is attached to an end part of the body 140.

  An inlet port 144 for introducing a high-pressure refrigerant is provided on the side of the body 140, and an outlet port 146 for deriving the low-pressure refrigerant is provided on the lower part. These ports communicate with each other through a refrigerant passage that is orthogonal within the body 140. A disc-shaped partition member 148 is provided in an intermediate portion of the refrigerant passage, and a valve hole 150 (corresponding to a “first valve hole”) is formed so as to penetrate the partition member 148. A valve body 152 (corresponding to a “first valve body”) is arranged so as to face the valve hole 150 from the downstream side. The partition member 148 has a step portion formed in a concave shape at a portion facing the valve body 152, and a guide hole 154 is formed so as to penetrate the center of the step portion. The valve hole 150 is formed by a plurality of through holes provided at predetermined intervals around the guide hole 154 in the stepped portion. In the refrigerant passage, the upstream side of the partition member 148 becomes a high-pressure refrigerant passage 156 and the downstream side becomes a low-pressure refrigerant passage 158.

  A communication hole 160 that allows the high-pressure refrigerant passage 156 to communicate with the inside and outside is formed in the upper portion of the body 140. A long operating rod 164 is integrally provided on the valve body 152. The operation rod 164 is slidably inserted into the guide hole 154 and extends so as to reach the communication hole 160. A cylindrical guide member 166 is press-fitted into the upper end portion of the operating rod 164. The guide member 166 is slidably supported along the inner wall of the communication hole 160. That is, the valve body 152 operates in the opening / closing direction of the valve portion by being driven in the axial direction while the operating rod 164 is guided along the guide hole 154 and the communication hole 160. In the present embodiment, the diameter of the communication hole 160 and the diameter of the valve hole 150 are configured to be substantially equal. As a result, the pressure due to the high-pressure refrigerant acting directly or indirectly on the valve body 152 is canceled. Has been.

  A valve seat 168 is formed by the downstream opening edge of the valve hole 150, and the valve portion is opened and closed by attaching and detaching the tapered surface near the upper end of the valve body 152 to the valve seat 168. A predetermined clearance (corresponding to a “refrigerant leakage passage”) is provided between the communication hole 160 and the guide member 166, and a part of the refrigerant flowing through the high-pressure refrigerant passage 156 leaks through the clearance. A ring-shaped adjustment member 170 is press-fitted into the lower end opening of the body 140, and a spring 171 (“biasing member”) that biases the valve body 152 in the valve closing direction between the adjustment member 170 and the valve body 152. Is applicable). The spring load of the spring 171 can be adjusted by the press-fitting amount of the adjustment member 170 to the body 140.

  The power element 142 includes a hollow housing 172 and a diaphragm 174 (corresponding to a “pressure-sensitive member”) disposed so as to partition the housing 172 into a sealed space S1 and an open space S2. Yes. The housing 172 is composed of a lid-shaped upper housing 176 made of stainless steel and a stepped cylindrical lower housing 178, and these openings are brought into contact with each other so that an outer edge portion of a diaphragm 174 made of a thin metal plate such as stainless steel is formed on the outer edge portion thereof. It is assembled so as to sandwich it. The housing 172 is formed in a container shape by performing TIG welding or the like along the outer periphery of the joint portion with the diaphragm 174 sandwiched between the upper housing 176 and the lower housing 178. The sealed space S1 constitutes a reference pressure chamber, and is kept in a vacuum state in the present embodiment. That is, after the welding is performed in a vacuum atmosphere, the hole provided in the center of the upper surface is sealed with the ball-shaped sealing body 180. The sealing body 180 is made of, for example, stainless steel. The sealed space S1 constitutes a reference pressure chamber, and the open space S2 constitutes a pressure sensitive chamber. In the modification, the sealed space S1 may be filled with atmospheric pressure, for example.

  A disk-shaped spring receiving member 175 is disposed on the upper surface of the diaphragm 174. Between the bottom of the upper housing 176 and the spring receiving member 175, a spring 177 (corresponding to an “urging member”) for biasing the diaphragm 174 in the valve opening direction via the spring receiving member 175 is interposed. Yes. A flange portion 179 extending outward in the radial direction is provided at the upper end portion of the guide member 166, and the upper surface of the flange portion 179 is in contact with the lower surface of the diaphragm 174. With such a configuration, the driving force due to the displacement of the diaphragm 174 is transmitted to the valve body 152 via the guide member 166 and the operating rod 164. When the flange portion 179 is locked to the body 140, the bottom dead center position (the amount of displacement in the valve opening direction) of the diaphragm 174 is regulated.

  In the regulating valve 132, a part of the body 140 also serves as the body. That is, the body 140 is formed with a pressure adjusting passage 182 that connects the open space S2 and the regulating valve 132 separately from the refrigerant passage connecting the high-pressure refrigerant passage 156 and the low-pressure refrigerant passage 158. The pressure adjusting passage 182 forms an intermediate pressure chamber together with the pressure sensing chamber of the power element 142. As described above, since the high-pressure refrigerant leaks through the clearance from the high-pressure refrigerant passage 156, the intermediate pressure Pm equal to or higher than the set value (set pressure Pset) of the outlet pressure Px of the expansion valve 131 is filled in the intermediate pressure chamber. .

  The regulating valve 132 has a solenoid 184 that opens and closes its valve portion. The solenoid 184 is connected to a body forming portion 186 provided on the side portion of the body 140 opposite to the inlet port 144. A port 188 communicating with the refrigerant passage on the outlet side of the evaporator 4 is provided on the side of the body forming portion 186. The body forming portion 186 has an enlarged inner diameter at the connecting portion with the solenoid 184, and an opening edge at the center of the step portion projects in a circular boss shape to form a valve seat 190. In addition, a valve hole (corresponding to a “second valve hole”) is formed inside the circular boss portion that forms the valve seat 190.

  The solenoid 184 is extrapolated to a stepped cylindrical case 191 that also functions as a yoke, a core 192 that is fixed in the case 191, a plunger 193 that is opposed to the core 192 in the axial direction, and a core 192. A sleeve 194 made of a cylindrical nonmagnetic material, and an electromagnetic coil 195 that is extrapolated to the sleeve 194 and generates a magnetic circuit by a supply current from the outside are provided. In the sleeve 194, a plunger 193 is disposed so as to be able to advance and retract in the axial direction with respect to the core 192. One end of the case 191 is reduced in diameter and is press-fitted into the body forming portion 186, whereby the solenoid 184 is assembled to the body 140.

  The plunger 193 has a cylindrical shape, and a surface facing the valve seat 190 is formed flat. A portion facing the valve seat 190 serves as a valve body portion 196 (corresponding to a “second valve body”), and is configured to be detachable from the valve seat 190 so that the valve portion can be opened and closed. The plunger 193 faces the core 192 on the side opposite to the valve seat 190, and the facing surface forms a tapered surface whose diameter decreases toward the core 192 side. On the other hand, the core 192 has a concave portion at the center of the surface facing the plunger 193, and has a complementary tapered surface that widens toward the plunger 193 side. A spring 198 that biases the plunger 193 in the valve closing direction is interposed between the core 192 and the plunger 193. And the connector part 200 is provided so that the other end side of the solenoid 184 may be sealed. The connector part 200 is formed by resin-molding electrode terminals connected to the electromagnetic coil 195 and is crimped and joined to the case 191 with a ring-shaped collar 202 interposed. The collar 202 is made of a magnetic member and forms a magnetic circuit together with the case 191.

  In the above configuration, the refrigerant sent from the condenser 2 side and introduced into the inlet port 144 at the inlet pressure Po becomes the outlet pressure Px by passing through the valve portion, and is led out from the outlet port 146. 4 is supplied. The set value (set pressure Pset) of the outlet pressure Px is set to a basic set value determined by the effective pressure receiving area of the diaphragm 174 and the balance between the spring 171 and the spring 177. However, the setting value can be changed by the adjusting valve 132. It has become. A part of the refrigerant introduced into the evaporator 4 at the inlet pressure Pe is introduced into the port 188. The inlet pressure Pe is slightly lower than the outlet pressure Px of the expansion valve 131, but can be considered to be substantially equal.

  The regulating valve 132 is configured as a differential pressure valve that can change the differential pressure across the valve portion by a solenoid 184, and controls the differential pressure between the intermediate pressure Pm that is the refrigerant pressure in the pressure adjusting passage 182 and the inlet pressure Pe. To do. When the regulating valve 132 is in the fully open state, the intermediate pressure Pm and the inlet pressure Pe are equal. Since the refrigerant leaks from the high-pressure refrigerant passage 156 through the clearance into the pressure adjusting passage 182, the intermediate pressure Pm is always satisfied. In other words, the intermediate pressure Pm is the basic set value (reference pressure). When the opening degree of the regulating valve 132 is adjusted and the differential pressure ΔP is generated, the relationship between the intermediate pressure Pm and the inlet pressure Pe is expressed by the following formula (1).

Pe = Pm−ΔP (1)
That is, by changing the differential pressure across the regulating valve 132, the set value (set pressure Pset) of the inlet pressure Pe of the evaporator 4 and thus the outlet pressure Px of the expansion valve 131 can be changed. The control unit changes the set pressure Pset by executing energization control to the adjustment valve 132 based on the external information. The power element 142 operates so that the outlet pressure Px is maintained at the set pressure Pset.

  In the expansion device 3 configured as described above, since the spring load of the spring 171 is set larger than the spring load of the spring 177, the expansion valve 131 is fully closed when the vehicle air conditioner is stopped. It becomes.

  Here, when the vehicle air conditioner is activated, the control unit controls the regulating valve 132 to a predetermined opening. At this time, since the refrigerant is sucked by the compressor, the inlet pressure Pe of the evaporator 4 decreases. As a result, the power element 12 senses this, and the diaphragm 174 is displaced in the valve opening direction. The displacement is transmitted to the valve body 152, and the expansion valve 131 shifts to a predetermined valve open state.

  On the other hand, the refrigerant compressed by the compressor 1 is condensed by the condenser 2, and the liquid refrigerant separated by gas and liquid by a receiver (not shown) is supplied to the inlet port 144. The high-temperature / high-pressure liquid refrigerant is throttled and expanded when passing through the expansion valve 131, becomes a low-temperature / low-pressure gas-liquid mixed refrigerant, is supplied to the evaporator 4 from the outlet port 146, and is evaporated inside. Exchanges heat with the passenger compartment temperature. The refrigerant that has passed through the evaporator 4 is also introduced into the regulating valve 132 through the port 188, while returning to the compressor 1 through a pipe (not shown).

  The outlet pressure Px of the expansion valve 131 is held at the set pressure Pset during operation of the vehicle air conditioner. That is, when the outlet pressure Px becomes lower than the set pressure Pset, the power element 142 detects this, and the diaphragm 174 is displaced in the valve opening direction to increase the flow rate of refrigerant passing through the valve portion, thereby increasing the outlet pressure Px. . On the contrary, when the outlet pressure Px becomes higher than the set pressure Pset, the power element 142 detects this, and the diaphragm 174 is displaced in the valve closing direction to decrease the refrigerant flow rate passing through the valve portion, thereby reducing the outlet pressure Px. Let In this way, the outlet pressure Px is maintained at the set pressure Pset. This set pressure Pset can be changed by changing the set differential pressure of the regulating valve 132.

  As described above, the control valve 6 of the compressor 1 is configured as a flow control valve, while the expansion device 3 is configured as an expansion valve 131 (constant pressure expansion valve), for example, the following control can be effectively performed. Can be executed. FIG. 6 is a Mollier diagram for explaining the operation of the refrigeration cycle of the first embodiment. In the figure, the horizontal axis represents enthalpy and the vertical axis represents various pressures. A one-dot chain line in the figure represents an isotherm. Actually, there is a difference between the discharge chamber pressure Pdh of the compressor 1 and the outlet pressure Pdl with respect to the discharge pressure Pd, but this is simply shown as the discharge pressure Pd in FIG.

  1) As one of the external information, a temperature sensor (corresponding to a “refrigerant temperature detection unit”) that detects the outlet refrigerant temperature Te as one of the external information may be provided on the outlet side of the evaporator 4. And while a control part sets superheat degree SH of the refrigerant | coolant of the exit side of the evaporator 4 based on external information, based on the setting pressure Pset and exit refrigerant | coolant temperature Te which were set with respect to the expansion valve 131, refrigerant | coolant Are sequentially calculated. When the calculated superheat degree SH becomes larger than the set value, the control unit controls the energization of the control valve 6 so that the discharge capacity of the compressor 1 becomes larger. When the superheat degree SH becomes smaller than the set value, the control unit 6 performs compression. The control valve 6 may be energized to reduce the discharge capacity of the machine 1. For example, if the set value of the superheat degree SH is reduced, the temperature unevenness of the evaporator 4 can be suppressed. Thereby, the blowing temperature of the air which passes the evaporator 4 can be equalized over the full length. Specifically, it is possible to reduce the temperature difference between the air temperature t21 at a position away from the outlet of the evaporator 4 shown in FIG. it can. As a result, the dehumidifying performance of the refrigeration cycle can be maintained high.

  2) As shown in FIG. 1, the temperature of the air in the vicinity of the evaporator 4 is one of the external information, and the first air temperature t21 and the second air temperature at the upstream position and the downstream position with respect to the refrigerant flow, respectively. A temperature sensor (corresponding to an “air temperature detector”) that is detected as t22 may be provided. Then, the control unit sets a target temperature difference between the second air temperature t22 and the first air temperature t21 based on the external information, and the temperature difference between the second air temperature and the first air temperature detected by the temperature sensor. When Δt becomes larger than the target temperature difference, the control valve 6 may be energized and controlled such that the discharge capacity of the compressor 1 is increased. Thus, by reducing the temperature unevenness of the heat exchange by the evaporator 4, the evaporation temperature of the air can be stabilized and the dehumidification performance can be maintained high.

  3) As one of the external information, a temperature sensor (corresponding to a “refrigerant temperature detection unit”) that detects the refrigerant temperature Td at a predetermined position on the outlet side of the compressor 1 may be provided. And a control part sets the refrigerant | coolant temperature of the predetermined position based on external information, and when the refrigerant | coolant temperature Td detected by the temperature sensor becomes higher than a setting value, it controls so that the discharge capacity of the compressor 1 becomes small. The valve 6 may be energized and controlled. Thus, by monitoring the refrigerant temperature Td, it is possible to prevent the temperature of the discharged refrigerant from becoming an abnormally high temperature. Or you may make it perform the same control based on the refrigerant | coolant temperature of an internal predetermined position instead of the exit side predetermined position of the compressor 1. FIG.

  4) As one of the external information, a pressure sensor (corresponding to a “refrigerant pressure detection unit”) that detects the discharge pressure Pd at a predetermined position on the outlet side of the compressor 1 may be provided. Then, the control unit sets the discharge pressure Pd at the predetermined position based on the external information, and when the discharge pressure Pd detected by the pressure sensor becomes higher than the set value, the discharge capacity of the compressor 1 is reduced. The control valve 6 may be energized and controlled. Thereby, it is possible to prevent the discharge pressure Pd from becoming abnormally high. In this aspect, the discharge pressure Pd of the compressor 1 can be acquired from the output value of the pressure sensor, and the suction pressure Ps can be acquired as being substantially equal to the set pressure Pset of the expansion device 3. Further, since the flow rate control method is adopted, the set flow rate can be acquired as the refrigerant discharge flow rate. For this reason, the motive power of the compressor 1 can be estimated easily and the control which implement | achieves the efficiency improvement of a refrigerating cycle can be performed easily.

  As described above, in the present embodiment, since the valve opening is autonomously adjusted so that the downstream pressure of the expansion device 3 becomes the set pressure Pset, the set pressure Pset is appropriately set. By doing so, the refrigerant pressure in the evaporator 4 can be maintained at an appropriate value, the evaporation temperature can be stably maintained, and a desired dehumidifying performance by the evaporator 4 can be obtained. On the other hand, since the control valve 6 can be configured as a flow control valve and the discharge capacity of the compressor 1 can be directly controlled, the response of the capacity control can be kept good. As a result, the air conditioning performance can be maintained high without complicating the device configuration and the control method.

  Further, in the present embodiment, the expansion device 3 is constituted by the expansion valve 131 and the regulating valve 132, and the differential pressure between the intermediate pressure Pm in the pressure regulating passage 182 and the inlet pressure Pe of the evaporator 4 by the regulating valve 132. To control. That is, the set value of the constant pressure expansion valve is changed by the differential pressure valve. The adjustment valve 132 does not control the main flow rate like the expansion valve 131 but controls the flow of refrigerant leaking from the high-pressure refrigerant passage 156, so that the valve opening degree can be kept small. And control becomes easy. Since the main flow rate is not controlled, the flow rate through the valve portion is small, and the flow noise is also kept small. Further, since the effective pressure receiving area of the valve portion (valve body portion 196) can be reduced, the solenoid 184 can be made compact.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. This embodiment is substantially the same as the first embodiment except that an internal heat exchanger is provided in the refrigeration cycle. For this reason, about the component similar to 1st Embodiment, the same code | symbol is attached | subjected as needed, and the description is abbreviate | omitted suitably. FIG. 7 is a system configuration diagram showing a refrigeration cycle according to the second embodiment.

  As shown in FIG. 7, in the refrigeration cycle of the present embodiment, an internal heat exchange is performed between the refrigerant sent from the condenser 2 to the expansion device 3 and the refrigerant sent from the evaporator 4 to the compressor 1. A heat exchanger 205 is provided. The internal heat exchanger 205 has a double tube structure, and the refrigerant flowing from the evaporator 4 toward the compressor 1 passes through the inner passage, and the refrigerant flowing from the condenser 2 toward the expansion device 3 is outside. Go through the passage. Thus, the refrigerant flowing from the condenser 2 toward the expansion device 3 is cooled by the refrigerant flowing from the evaporator 4 toward the compressor 1, while the refrigerant flowing from the evaporator 4 toward the compressor 1 is condensed. Heated by the refrigerant flowing from the vessel 2 toward the expansion device 3, the heat exchange rate of the refrigeration cycle is increased.

  The expansion valve 131 of the expansion device 3 senses the pressure on the outlet side of the evaporator 4 (outlet pressure Pe). Also in the present embodiment, the control valve 6 of the compressor 1 is configured as a flow control valve, while the expansion device 3 is configured as an expansion valve 131 (constant pressure expansion valve). For example, the following control is effective. Can be executed. FIG. 8 is a Mollier diagram for explaining the operation of the refrigeration cycle of the second embodiment. In the figure, the horizontal axis represents enthalpy and the vertical axis represents various pressures. A one-dot chain line in the figure represents an isotherm. Actually, there is a difference between the discharge chamber pressure Pdh of the compressor 1 and the outlet pressure Pdl with respect to the discharge pressure Pd, but this is simply shown as the discharge pressure Pd in FIG. In the figure, SH represents the degree of superheat, and SC represents the degree of supercooling.

  1) As one of external information, a temperature sensor (corresponding to a “refrigerant temperature detection unit”) that detects the refrigerant temperature Ts on the inlet side of the compressor 1 may be provided. And a control part sets the superheat degree SH of the refrigerant | coolant of the inlet side of the compressor 1 based on external information (refer the figure (A)), the setting pressure Pset and refrigerant temperature Ts which were set with respect to the expansion apparatus 3 Based on the above, the superheat degree SH of the refrigerant may be calculated, and when the superheat degree SH becomes larger than a set value, the energization control of the control valve 6 may be performed so that the discharge capacity of the compressor 1 becomes large. Or you may provide the temperature sensor (it corresponds to a "refrigerant temperature detection part") which detects the exit side temperature Tlout of the low voltage | pressure side of the internal heat exchanger 205. FIG. Then, the control unit sets the superheat degree SH of the refrigerant on the low pressure side outlet side of the internal heat exchanger 205 based on the external information, and sets the set pressure Pset set for the expansion device 3 and the outlet side temperature Tlout. Based on this, the superheat degree SH of the refrigerant may be calculated, and when the superheat degree SH becomes larger than a set value, the control valve 6 may be energized and controlled so that the discharge capacity of the compressor 1 becomes large.

  2) As one of the external information, a temperature sensor (in the “refrigerant temperature detection unit”) that detects an inlet side temperature Thin and an outlet side temperature Thout of the internal heat exchanger 205 and an outlet side temperature Thlout of the low pressure side, respectively. Applicable) may be provided. And a control part sets the wetness degree of the refrigerant | coolant of the exit side of the evaporator 4 based on external information, and the refrigerant | coolant of the inlet side in the low voltage | pressure side of the internal heat exchanger 205 based on each refrigerant | coolant temperature detected by the temperature sensor. Is calculated (see FIG. 3B), and this is assumed to be the wetness of the refrigerant on the outlet side of the evaporator 4. If the assumed wetness is smaller than the set value, the control valve 6 is energized and controlled such that the discharge capacity of the compressor 1 is increased. If the wetness is greater than the set value, the discharge capacity of the compressor 1 is increased. The control valve 6 may be energized and controlled to be smaller.

  As shown in FIG. 5B, by keeping a certain degree of wetness at the outlet of the evaporator 4, the evaporation temperature is kept constant throughout the evaporator 4 and the air blowing temperature is kept uniform. Can do. In the illustrated example, the temperature difference between the first air temperature te1 and the second air temperature te2 of the evaporator 4 can be reduced. As a result, the dehumidifying performance can be enhanced. In addition, by providing the refrigerant flowing through the evaporator 4 with a certain degree of wetness, it becomes easier to send the lubricating oil contained in the refrigerant to the compressor 1 side even at low loads, that is, it is easier to circulate the refrigeration cycle. There are also advantages. On the other hand, the compression efficiency of the compressor 1 can be kept high by providing a predetermined superheat degree SH at the inlet of the compressor 1 as shown in FIG. Since the efficiency of the refrigeration cycle tends to decrease when the wetness level is large, the control unit may perform control so as to limit the period during which the wetness level is given to a specific period.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the specific embodiments, and various modifications can be made within the scope of the technical idea of the present invention. Needless to say.

  In the above-described embodiment, the expansion device 3 is configured such that the adjustment valve 132 is assembled to the expansion valve 131, the intermediate pressure Pm is reduced, and the set pressure Pset of the outlet pressure Px can be changed. In the modification, a mechanism that does not have such a pressure control valve can be employed. FIG. 9 is a cross-sectional view illustrating a configuration of an expansion device according to a modification. In this modification, the same components as those shown in FIG. 5 are denoted by the same reference numerals, and description thereof is omitted.

The expansion device 203 is configured by assembling an expansion valve 231 configured as a constant pressure expansion valve and a pressure adjusting mechanism 232 for adjusting the set pressure of the expansion valve 231.
The expansion valve 231 includes a body 240 having a valve portion provided therein. A power element 242 that opens and closes the valve portion is attached to the end of the body 240.

  A cylindrical guide member 266 is press-fitted into the upper end portion of the operating rod 164. The guide member 266 is slidably supported along the inner wall of the communication hole 160. A concave portion is provided around the side portion of the guide member 266, and an O-ring 270 for sealing is fitted. That is, in the expansion valve 231, the refrigerant in the high-pressure refrigerant passage 156 is prevented from leaking into the open space S2. Also in this modification, the diameter of the communication hole 160 and the diameter of the valve hole 150 are configured to be substantially equal. As a result, the pressure by the high-pressure refrigerant acting directly or indirectly on the valve body 152 is Canceled.

  The housing 272 of the power element 242 has an upper housing 276 that is open to the atmosphere, and forms an open space S21 unlike the above embodiment. A pressure adjusting mechanism 232 is disposed so as to face the open space S21. The pressure adjusting mechanism 232 includes a drive rod 282 that can be moved forward and backward with respect to the diaphragm 174 and an actuator 284 that drives the drive rod 282. The actuator can be constituted by, for example, a solenoid or a geared motor. The drive rod 282 is operatively connected to the diaphragm 174 via a disk-shaped disk 280, a spring 177, and a spring receiving member 175. The drive rod 282 is driven in the axial direction by the actuator 284 to advance and retract in the valve opening / closing direction, and urges the valve body 152 in the valve opening direction together with the spring 177. The control unit controls energization of the actuator to control the amount of displacement of the drive rod 282 in the valve opening direction, thereby adjusting the valve opening characteristic of the expansion valve 231, that is, the set pressure Pset of the outlet pressure Px.

  This modification is different from the above-described embodiment in that the expansion device 203 does not have a control valve for pressure adjustment, and the actuator 284 has a form in which the set load of the spring 177 is directly changed. In this case, the actuator 284 needs to resist the load caused by the refrigerant pressure acting on the relatively large effective pressure receiving area of the diaphragm 174. For this reason, for example, when the actuator 284 is composed of a solenoid, a large solenoid force is required depending on the change range of the set pressure Pset. In other words, the above embodiment has an advantage that the solenoid can be configured more compactly.

  In the first embodiment, an example in which the pressure sensing chamber of the power element 142 in the expansion valve 131 communicates with the refrigerant passage on the inlet side of the evaporator 4 via the valve portion of the regulating valve 132 has been described. You may comprise so that it may connect with the refrigerant | coolant channel | path of 4 exit side (inlet side of the compressor 1). Similarly, in the second embodiment, the example in which the power element 142 in the expansion valve 131 communicates with the refrigerant passage on the outlet side of the evaporator 4 via the valve portion of the regulating valve 132 has been described. It may be configured to communicate with the refrigerant passage on the inlet side of the compressor or on the inlet side of the compressor 1 (low-pressure side outlet side of the internal heat exchanger 205).

  In the above embodiment, a so-called flow rate control type compressor that uses a flow rate control valve to maintain a discharge flow rate at a set flow rate has been exemplified. In the modification, for example, a differential pressure between two predetermined points of the refrigeration cycle is set, such as a so-called Pd-Ps valve that performs capacity control based on a differential pressure (Pd-Ps) between the discharge pressure Pd and the suction pressure Ps. You may employ | adopt the compressor of the system hold | maintained to a pressure.

  The compressor of the above embodiment is preferably applied to a refrigeration cycle that uses alternative chlorofluorocarbon (HFC-134a) or the like as a refrigerant. However, the variable capacity compressor of the present invention is a refrigerant having a high operating pressure such as carbon dioxide. It is also possible to apply to a refrigeration cycle using In that case, an external heat exchanger such as a gas cooler is arranged in place of the condenser in the refrigeration cycle.

It is a system configuration figure showing the refrigerating cycle concerning a 1st embodiment. It is sectional drawing showing the structure of a compressor. It is sectional drawing which shows the structure of a control valve. FIG. 4 is an enlarged view of the upper half of the control valve shown in FIG. 3. It is sectional drawing which shows the structure of an expansion apparatus. It is a Mollier diagram explaining operation | movement of the refrigerating cycle of 1st Embodiment. It is a system configuration figure showing the refrigerating cycle concerning a 2nd embodiment. It is a Mollier diagram explaining operation | movement of the refrigerating cycle of 2nd Embodiment. It is sectional drawing which shows the structure of the expansion apparatus which concerns on a modification.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Variable capacity compressor, 2 Condenser, 3 Expansion apparatus, 4 Evaporator, 5 Fan, 6 Control valve, 8 Valve body, 9 Solenoid, 10 Body, 12 Power element, 15 Valve hole, 16 Valve seat, 18 Valve body , 19 Valve seat forming part, 20 Guide hole, 22 Valve body, 26 Valve hole, 27 Valve seat, 36 Shaft, 51 Suction chamber, 52 Cylinder, 53 Discharge chamber, 54 Crank chamber, 71 Inlet port, 72 Outlet port, 73 Communication port, 76 damper chamber, 90 connector, 111 swing plate, 112 piston, 121 suction relief valve, 131 expansion valve, 132 regulating valve, 140 body, 142 power element, 144 inlet port, 146 outlet port, 148 partition member , 150 valve hole, 152 valve body, 1 54 Guide hole, 156 High-pressure refrigerant passage, 158 Low-pressure refrigerant passage, 164 Actuating rod, 166 Guide member, 168 Valve seat, 170 Adjustment member, 172 Housing, 174 Diaphragm, 182 Pressure regulation passage, 184 Solenoid, 186 Body forming portion, 188 Port, 190 valve seat, 196 valve body, 200 connector, 203 expansion device, 205 internal heat exchanger, 231 expansion valve, 232 pressure regulating mechanism, 240 body, 242 power element, 266 guide member, 270 O-ring, 282 Drive rod, 284 actuator, S1 sealed space, S2 open space, S21 open space.

Claims (11)

In the refrigeration cycle constituting the air conditioner,
A variable capacity compressor in which the refrigerant sucked from the suction chamber is compressed and discharged from the discharge chamber, and the discharge capacity of the refrigerant changes according to the crank pressure in the crank chamber;
An external heat exchanger for cooling the refrigerant discharged from the variable capacity compressor;
The refrigerant sent from the external heat exchanger is drawn out by being expanded by passing through an internal valve portion, and the valve opening degree is autonomous so that the downstream pressure of the drawn refrigerant becomes the set pressure. An inflating device that is adjusted
An evaporator for evaporating the refrigerant derived from the expansion device to exchange heat with the outside, and sending the refrigerant to the variable capacity compressor;
The variable capacity compressor is controlled by controlling a flow rate of refrigerant introduced from the discharge chamber of the variable capacity compressor into the crank chamber so that a differential pressure or a flow rate between two predetermined points of the refrigeration cycle becomes a set value. A control valve that changes the discharge capacity of
A refrigeration cycle comprising:   2. The refrigeration cycle according to claim 1, wherein the control valve is configured as a flow rate control valve that controls the flow rate of the refrigerant led out from the refrigerant outlet of the variable capacity compressor to be a set flow rate. . While the set pressure of the expansion device is configured to be electrically changeable, the set flow rate of the control valve is configured to be electrically changeable,
The set pressure and the set flow rate are determined based on predetermined external information, energization control to the expansion device is executed according to the determined set pressure, and to the control valve according to the determined set flow rate The refrigeration cycle according to claim 2, further comprising: a control unit that executes the energization control. The control valve is
A first refrigerant passage communicating the refrigerant outlet of the variable capacity compressor and the discharge chamber;
A main valve for opening and closing the first refrigerant passage;
A second refrigerant passage communicating the discharge chamber and the crank chamber;
A sub-valve that opens and closes the second refrigerant passage by being displaced relative to the main valve;
A solenoid capable of driving the auxiliary valve in the opening and closing direction and driving the main valve in the opening direction when the auxiliary valve is closed,
4. The refrigeration cycle according to claim 3, wherein the flow rate of the refrigerant led out from the refrigerant outlet through the main valve is controlled to be a set flow rate corresponding to a current value supplied to the solenoid. The control valve is
The main valve includes a valve seat formed in the first refrigerant passage, and a main valve body that contacts and separates the valve seat from the downstream side in a state of being biased in a valve closing direction by a biasing member,
The sub-valve is a cylindrical body that receives a solenoid force in the valve opening direction and contacts and separates the main valve body as a movable valve seat, and one opening portion thereof opens and closes to and from the main valve body In addition, when the valve is opened, the valve body communicates with an inlet port that opens to the discharge chamber, and the other opening communicates with a communication port that communicates with the crank chamber. The refrigeration cycle according to claim 4, further comprising a sub-valve element that can be transmitted as an urging force in the valve opening direction. As one of the external information, further comprising a refrigerant temperature detection unit for detecting the refrigerant temperature on the outlet side of the evaporator,
The controller sets the degree of superheat of the refrigerant on the outlet side of the evaporator based on the external information, and based on the set pressure set for the expansion device and the refrigerant temperature on the outlet side of the evaporator The superheat degree of the refrigerant is calculated, and when the superheat degree becomes larger than a set value, the control valve is controlled so that the discharge capacity of the variable capacity compressor becomes larger, and the superheat degree is smaller than the set value. The refrigeration cycle according to any one of claims 3 to 5, wherein the control valve is controlled so that a discharge capacity of the variable capacity compressor is reduced. As one of the external information, the temperature of the air in the vicinity of the evaporator that has passed through the evaporator is detected as the first air temperature and the second air temperature, respectively, at the upstream position and the downstream position with respect to the refrigerant flow. An air temperature detector
The control unit sets a target temperature difference between the second air temperature and the first air temperature based on the external information, and the second air temperature and the first air temperature detected by the air temperature detection unit are set. 6. The refrigeration cycle according to claim 3, wherein the control valve is controlled so that a discharge capacity of the variable capacity compressor is increased when the temperature difference of the variable capacity compressor is larger than the target temperature difference. . As one of the external information, further comprising a refrigerant temperature detection unit that detects a refrigerant temperature at a predetermined position on the outlet side of the variable capacity compressor, or a refrigerant temperature at a predetermined position inside the variable capacity compressor,
The control unit sets the refrigerant temperature at the predetermined position based on the external information, and when the refrigerant temperature detected by the refrigerant temperature detection unit becomes higher than a set value, the discharge capacity of the variable capacity compressor becomes small. The refrigeration cycle according to any one of claims 3 to 5, wherein the control valve is controlled so as to become. As one of the external information, further comprising a refrigerant pressure detector that detects a refrigerant pressure at a predetermined position on the outlet side of the variable capacity compressor,
The control unit sets the refrigerant pressure at the outlet-side predetermined position based on the external information, and when the refrigerant pressure detected by the refrigerant pressure detection unit becomes higher than a set value, the discharge capacity of the variable capacity compressor The refrigeration cycle according to any one of claims 3 to 5, wherein the control valve is controlled so as to be small. An internal heat exchanger that exchanges heat between the refrigerant sent from the external heat exchanger to the expansion device and the refrigerant sent from the evaporator to the variable capacity compressor;
As one of the external information, a refrigerant temperature detector that detects a refrigerant temperature on the inlet side of the variable capacity compressor or a refrigerant temperature on the low pressure side outlet side of the internal heat exchanger,
The control unit sets the superheat degree of the refrigerant on the inlet side of the variable capacity compressor or the low pressure side outlet side of the internal heat exchanger based on the external information, and a set pressure set for the expansion device; And calculating the degree of superheat of the refrigerant based on the refrigerant temperature detected by the refrigerant temperature detection unit, and when the degree of superheat exceeds a set value, the control is performed so that the discharge capacity of the variable capacity compressor is increased. The refrigeration cycle according to any one of claims 3 to 5, wherein a valve is controlled. An internal heat exchanger that exchanges heat between the refrigerant sent from the external heat exchanger to the expansion device and the refrigerant sent from the evaporator to the variable capacity compressor;
As one of the external information, a refrigerant temperature detector that detects an inlet side temperature and an outlet side temperature on the high pressure side and an outlet side temperature on the low pressure side of the internal heat exchanger,
The control unit sets the wetness of the refrigerant on the outlet side of the evaporator based on the external information, and the inlet side on the low pressure side of the internal heat exchanger based on each refrigerant temperature detected by the refrigerant temperature detection unit And the control valve is controlled so that the discharge capacity of the variable capacity compressor is increased if the wetness of the refrigerant on the outlet side of the evaporator estimated from the state is smaller than a set value. The refrigeration cycle according to any one of claims 3 to 5, wherein if the wetness is greater than a set value, the control valve is controlled so that a discharge capacity of the variable capacity compressor is reduced.

Images