JP5091757B2 - Capacity control system for variable capacity compressor - Google Patents

Description

  The present invention relates to a capacity control system for a variable capacity compressor applied to a refrigeration cycle of an air conditioning system.

  For example, as a variable capacity compressor used in an air conditioning system for vehicles, a swash plate type variable capacity compressor includes a housing, and inside the housing is a discharge pressure region (discharge chamber), a suction pressure region (suction chamber), a crank chamber, and a cylinder bore. Are partitioned. A swash plate is tiltably connected to a drive shaft extending in the crank chamber, and a conversion mechanism including the swash plate converts the rotation of the drive shaft into a reciprocating motion of a piston disposed in the cylinder bore. The reciprocating motion of the piston performs the steps of sucking the working fluid from the suction chamber into the cylinder bore, compressing the sucked working fluid, and discharging the compressed working fluid into the discharge chamber.

  The stroke length of the piston, that is, the discharge capacity of the compressor is variable by changing the crank chamber pressure (crank pressure Pc) as the control pressure. In order to control the discharge capacity, a capacity control valve is accommodated in the housing. The capacity control valve is disposed in an air supply passage that communicates the discharge chamber and the crank chamber, and a throttle is disposed in an extraction passage that communicates the crank chamber and the suction chamber.

For example, the displacement control valve described in FIG. 11 of Patent Document 1 has an operating rod and a solenoid unit. A discharge pressure Pd acts on the operating rod in the valve opening direction, and the suction pressure Ps and the solenoid unit electromagnetic Force acts in the valve closing direction.
When the capacity control valve of Patent Document 1 is used, the discharge capacity is feedback controlled so that the difference between the discharge pressure Pd and the suction pressure Ps (Pd−Ps differential pressure) approaches the target value. That is, in the air conditioner disclosed in Patent Document 1, the energization amount to the coil of the solenoid unit is changed using the Pd-Ps differential pressure as a control target, and the discharge capacity is changed accordingly. For example, in this air conditioner, if the Pd-Ps differential pressure is to be reduced, the discharge capacity is increased to operate the Pd-Ps differential pressure close to a predetermined value.

In addition, the variable capacity compressor described in FIG. 1 of Patent Document 1 is provided with a check valve capable of blocking between the discharge chamber of the compressor and the refrigerant circulation path. More specifically, the check valve blocks between the discharge chamber and the refrigerant circulation path when the compressor is in the minimum discharge capacity state (paragraph number 0081 of Patent Document 1).
JP 2001-153042 A

  When a variable capacity compressor is applied to a vehicle air conditioning system, the variable capacity compressor is designed so that the minimum mechanically defined discharge capacity is substantially zero. An external control method is used to control. In this case, as a control method (control mode) of the discharge capacity of the variable capacity compressor, generally, a control mode (air conditioning control mode) for increasing or decreasing the discharge capacity in accordance with the required cooling capacity is adopted.

  Here, as a control mode for reducing the power consumption of the variable capacity compressor as compared with the air conditioning control mode, the discharge capacity at the start of the variable capacity compressor is made as small as possible, and the discharge capacity is gradually increased after the start. It is conceivable to adopt a mode (startup control mode) that increases rapidly. According to this start control mode, when the variable capacity compressor is started, the discharge pressure is prevented from rising rapidly, and the driving load of the variable capacity compressor is reduced.

It is also conceivable to adopt a control mode (eco control mode) in which the discharge capacity of the variable capacity compressor is controlled so as to give priority to the reduction of power consumption over the securing of the cooling capacity.
However, the variable displacement compressor described in Patent Document 1 described above is provided with a check valve, and if the discharge capacity does not become larger than the minimum discharge capacity that is mechanically defined, The valve does not open. That is, even if it is going to start a compressor in start control mode, a refrigerant | coolant is not discharged from a compressor by a non-return valve, and there exists a possibility that a compressor cannot be started in start control mode.

In addition, when the eco-control mode is adopted, if the target of the discharge capacity is too small, there is a risk that the refrigerant will not be discharged from the compressor by the check valve. If the target of the discharge capacity is too large, the power consumption will be sufficient. Can not be reduced.
On the other hand, even when the air conditioning control mode is performed, if the target of the discharge capacity becomes too small as the cooling load decreases, the check valve does not discharge the refrigerant from the compressor, and the control of the discharge capacity becomes unstable. There is a fear.

The above-described problem is caused by the fact that the minimum discharge capacity that allows the refrigerant to be discharged from the compressor is not clearly defined when the check valve is used together with the variable capacity compressor.
The present invention has been made based on the above-described circumstances, and its object is to be applied to a variable capacity compressor used together with a check valve, and a minimum discharge that allows discharge of refrigerant from the compressor. A variable capacity compressor in which the capacity (hereinafter referred to as the effective minimum discharge capacity) is clearly defined so that the discharge capacity is stably controlled near the effective minimum discharge capacity and the power consumption of the variable capacity compressor is reduced. It is to provide a capacity control system.

  In order to achieve the above-described object, according to the present invention, a refrigerant is circulated in a circulation path for constituting a refrigeration cycle together with a radiator, an expander and an evaporator, and the capacity is increased based on a change in control pressure. In a variable capacity compressor capacity control system, a check valve provided between the variable capacity compressor and the radiator in the circulation path and opened at a predetermined set differential pressure, and the variable capacity compression And a valve body that acts in a direction in which the pressure in the suction pressure region of the variable capacity compressor and the electromagnetic force of the solenoid unit oppose the pressure in the discharge pressure region. , A displacement control valve that changes the control pressure by the operation of the valve body, external information detection means for detecting at least one external information, and external information detected by the external information detection means And a current adjusting means for adjusting a current supplied to the coil of the solenoid unit based on a set differential pressure of the check valve. A capacity control system for a variable capacity compressor is provided (claim). Item 1).

Preferably, the lower limit value of the current supplied to the coil by the current adjusting means is such that the differential pressure between the pressure in the discharge pressure region and the pressure in the suction pressure region exceeds the set differential pressure of the check valve. (Claim 2).
Preferably, the external information detection means includes discharge pressure detection means for detecting a pressure in the discharge pressure area, and the current adjustment means is based on the external information detected by the external information detection means. Target suction pressure setting means for setting a target suction pressure that is a target value of the pressure of the pressure, and the pressure in the discharge pressure region detected by the discharge pressure detection means, the target set by the target suction pressure setting means The current supplied to the coil is adjusted based on the suction pressure and the set differential pressure of the check valve.

  Preferably, the external information detection means includes a thermal load detection means for detecting a thermal load of the refrigeration cycle, and the target suction pressure setting means has a request to change the variable capacity compressor from an inoperative state to an activated state. If so, an initial value of the target suction pressure is set based on the thermal load detected by the thermal load detecting means when the variable capacity compressor is in an inoperative state.

Preferably, the discharge pressure detection means also serves as the thermal load detection means, and the target suction pressure setting means is detected by the discharge pressure detection means when the variable capacity compressor is in an inoperative state. An initial value of the target suction pressure is set based on the pressure in the discharge pressure region or a value related to the pressure.
Preferably, the discharge pressure detecting means includes a pressure sensor that is installed downstream from the check valve and detects a pressure in the high pressure region of the refrigeration cycle as a value related to the pressure in the discharge pressure region. The suction pressure setting means determines the initial value of the target suction pressure based on the pressure in the high pressure region detected by the pressure sensor when the variable capacity compressor is in an inoperative state and the check valve is closed. Set (Claim 6).

Preferably, the target suction pressure setting means gradually decreases the target suction pressure from the initial value (claim 7).
Preferably, when the initial value of the target suction pressure is less than a preset lower limit value or exceeds a preset upper limit value, the variable capacity compressor is maintained in a non-operating state (Claim 8). ).

  Preferably, the current adjusting means calculates a target differential pressure that is a target value of a differential pressure between the pressure in the discharge pressure area and the pressure in the suction pressure area based on the external information detected by the external information detecting means. A target differential pressure setting means for setting is included, and a current supplied to the coil is adjusted based on the target differential pressure set by the target differential pressure setting means and the set differential pressure of the check valve. 9).

Preferably, when the variable capacity compressor is switched from the non-operating state to the operating state, the initial value of the current supplied to the coil by the current adjusting means is set based on a set differential pressure of the check valve. (Claim 10).
Preferably, the initial value of the current is set in consideration of a variation in one or both of a set differential pressure of the check valve and an operation characteristic of the capacity control valve so that the variable compressor is reliably started. (Claim 11).

Preferably, the current adjusting means gradually increases the current supplied to the coil from the initial value (claim 12).
Preferably, the variable displacement compressor has a housing in which the discharge pressure region, the crank chamber, the suction pressure region, and a cylinder bore are defined, a piston disposed in the cylinder bore, and a rotation in the housing. A drive shaft supported by the drive shaft, a conversion mechanism including a variable tilt swash plate element that converts the rotation of the drive shaft into a reciprocating motion of the piston, an air supply passage communicating the discharge chamber and the crank chamber, A bleed passage that communicates the crank chamber and the suction chamber is provided, and the capacity control valve is interposed in the air supply passage.

  Preferably, the variable capacity compressor is a clutchless compressor.

  In the capacity control system of the variable capacity compressor according to the first aspect of the present invention, the current supplied to the coil is adjusted based on the external information and the set differential pressure of the check valve. By considering the set differential pressure of the check valve, the discharge capacity control is accurately performed up to the effective minimum discharge capacity, and the discharge capacity control near the effective minimum discharge capacity becomes stable. In addition, the power consumption of the variable capacity compressor is reduced by accurately controlling the discharge capacity in the vicinity of the effective minimum discharge capacity.

  In the capacity control system of the variable capacity compressor according to claim 2, when a current is supplied to the coil, the difference between the pressure (discharge pressure) in the discharge pressure area and the pressure (intake pressure) in the suction pressure area of the variable capacity compressor. Since (Pd-Ps differential pressure) exceeds the set differential pressure of the check valve, the refrigerant is discharged from the compressor. As a result, according to this capacity control system, discharge capacity control is accurately performed up to the effective minimum discharge capacity.

In the capacity control system of the variable capacity compressor according to claim 3, the discharge capacity control range is wide by adjusting the current supplied to the coil based on the discharge pressure and the target suction pressure. In addition, by adjusting the current based on the set differential pressure of the check valve, the discharge capacity control is accurately performed up to the effective minimum discharge capacity, and the entire area of the wide control range is effectively utilized.
In the capacity control system of the variable capacity compressor according to the fourth aspect, the suction pressure when the compressor is in the non-operating state is detected or estimated by using the heat load detected by the heat load detecting means. The initial value of the target suction pressure is easily and accurately set based on the detected or estimated suction pressure.

According to the capacity control system of the variable capacity compressor of claim 5, since the discharge pressure detecting means also serves as the heat load detecting means, it is not necessary to newly add the heat load detecting means, and the system configuration is simplified. The
According to the capacity control system of the variable capacity compressor of claim 6, when the check valve is closed, the pressure in the high pressure region is detected by the pressure sensor, so that the variable capacity compressor is in the non-operating state. The suction pressure is substantially detected. Then, the initial value of the target suction pressure is set easily and accurately by setting the initial value of the target suction pressure with reference to the detected pressure in the high pressure region.

As a result, according to this capacity control system, when the variable capacity compressor is started from the non-operating state to the operating state, the drive load and discharge pressure of the variable capacity compressor are suppressed from rapidly increasing, As the power consumption is reduced, the discharge capacity control is stabilized.
According to the capacity control system of the variable capacity compressor of claim 7, the drive load and the discharge pressure are rapidly increased even after the variable capacity compressor is in an operating state by gradually decreasing the target suction pressure. It is suppressed. For this reason, for example, according to the air conditioning system to which the capacity control system of the variable capacity compressor is applied, the air conditioning is smoothly performed after the variable capacity compressor is started.

According to the capacity control system of the variable capacity compressor of claim 8, the operation of the variable capacity compressor is avoided in the region where the operation of the variable capacity compressor is to be restricted, and the reliability of the variable capacity compressor is ensured. The
In the capacity control system of the variable capacity compressor according to claim 9, since the current supplied to the coil is adjusted based on the target differential pressure that is the target value of the Pd-Ps differential pressure, the control range of the discharge capacity is wide. . In addition, by adjusting the current based on the set differential pressure of the check valve, the discharge capacity control is accurately performed up to the effective minimum discharge capacity, and the entire area of the wide control range is effectively utilized.

  According to the capacity control system of the variable capacity compressor of claim 10, when starting the variable capacity compressor from the non-operating state to the operating state, the initial value of the current is set based on the set differential pressure of the check valve. Thus, the differential pressure is substantially minimized within the discharge capacity control range. For this reason, when the variable capacity compressor is started, a sudden increase in the driving load and discharge pressure of the variable capacity compressor is suppressed, power consumption is reduced, and discharge capacity control is stabilized.

According to the capacity control system of the variable capacity compressor of claim 11, the variable capacity compressor is reliably started.
According to the capacity control system of the variable capacity compressor of the twelfth aspect, even when the variable capacity compressor is in an operating state by gradually increasing the value of the current supplied to the coil, the drive load and the discharge pressure are controlled. Rapid increase is suppressed. For this reason, for example, in an air conditioning system to which the variable capacity compressor capacity control system is applied, air conditioning is smoothly performed after the variable capacity compressor is in an operating state.

In the capacity control system of the variable capacity compressor according to claim 13, the variable capacity compressor is a reciprocating type variable capacity compressor having a swash plate element, and the mechanical variable range of the discharge capacity is wide, and this wide variable range. Is effectively utilized.
Since the clutchless compressor is often used together with a check valve, the variable capacity compressor capacity control system according to claim 14 is easily applied to the clutchless compressor without adding a new check valve. Is done.

  FIG. 1 shows a refrigeration cycle (refrigeration circuit) 10 of a vehicle air conditioning system. The refrigeration cycle 10 includes a circulation path (external circulation path) 12 through which a refrigerant as a working fluid circulates. A compressor 100, a radiator (condenser) 14, an expander (expansion valve) 16, and an evaporator 18 are sequentially inserted into the circulation path 12 in the flow direction of the refrigerant. The refrigerant circulates through the path 12. That is, the compressor 100 performs a series of processes including a refrigerant suction process, a suction refrigerant compression process, and a compressed refrigerant discharge process.

The evaporator 18 also constitutes a part of an air circuit of the vehicle air conditioning system, and the air flow passing through the evaporator 18 is cooled by taking heat of vaporization by the refrigerant in the evaporator 18.
The compressor 100 to which the capacity control system A of the first embodiment is applied is a variable capacity compressor, for example, a reciprocating swash plate type clutchless compressor. The compressor 100 includes a cylinder block 101, and the cylinder block 101 is formed with a plurality of cylinder bores 101a. A front housing 102 is connected to one end of the cylinder block 101, and a rear housing (cylinder head) 104 is connected to the other end of the cylinder block 101 via a valve plate 103.

  The cylinder block 101 and the front housing 102 define a crank chamber 105, and a drive shaft 106 extends longitudinally through the crank chamber 105. The drive shaft 106 passes through an annular swash plate 107 disposed in the crank chamber 105, and the swash plate 107 is hinged to a rotor 108 fixed to the drive shaft 106 via a connecting portion 109. Accordingly, the swash plate 107 can tilt while moving along the drive shaft 106. That is, the angle (tilt angle) formed by the normal line of the swash plate 107 and the axis line of the drive shaft 106 is variable, and the minimum value (minimum tilt angle) of the tilt angle is approximately 0 °.

A portion of the drive shaft 106 extending between the rotor 108 and the swash plate 107 is provided with a coil spring 110 that urges the swash plate 107 toward the minimum inclination angle. A coil spring 111 that urges the swash plate 107 toward the maximum inclination angle is attached to a portion of the drive shaft 106 that extends between the swash plate 107 and the cylinder block 101.
The drive shaft 106 penetrates through a boss portion 102a protruding outside the front housing 102, and is connected to a pulley 112 as a power transmission device at the outer end of the drive shaft 106. The pulley 112 is rotatably supported by a boss portion 102a via a ball bearing 113, and a belt 115 is wound around the engine 114 as an external drive source.

A shaft seal device 116 is disposed inside the boss portion 102a to block the inside and the outside of the front housing 102 from each other. The drive shaft 106 is rotatably supported by bearings 117, 118, 119, and 120 in the radial direction and the thrust direction. Power from the engine 114 is transmitted to the pulley 112, and can rotate in synchronization with the rotation of the pulley 112.
A piston 130 is disposed in the cylinder bore 101a, and a tail portion protruding into the crank chamber 105 is formed integrally with the piston 130. A pair of shoes 132 is disposed in a recess 130a formed in the tail portion, and the shoes 132 are in sliding contact with the outer peripheral portion of the swash plate 107 so as to be sandwiched therebetween. Therefore, the piston 130 and the swash plate 107 are interlocked with each other via the shoe 132, and the piston 130 reciprocates in the cylinder bore 101a by the rotation of the drive shaft 106.

  A suction chamber (suction pressure region) 140 and a discharge chamber (discharge pressure region) 142 are defined in the rear housing 104, and the suction chamber 140 communicates with the cylinder bore 101 a through a suction hole 103 a provided in the valve plate 103. Is possible. The discharge chamber 142 communicates with the cylinder bore 101a through a discharge hole 103b provided in the valve plate 103. The suction hole 103a and the discharge hole 103b are opened and closed by a suction valve and a discharge valve (not shown), respectively.

  A muffler 150 is provided outside the cylinder block 101, and the muffler casing 152 is joined to a muffler base 101b formed integrally with the cylinder block 101 via a seal member (not shown). The muffler casing 152 and the muffler base 101b define a muffler space 154, and the muffler space 154 communicates with the discharge chamber 142 via a discharge passage 156 that passes through the rear housing 104, the valve plate 103, and the muffler base 101b.

A discharge port 152a is formed in the muffler casing 152, and a check valve 200 is disposed in the muffler space 154 so as to block between the discharge passage 156 and the discharge port 152a.
As shown in FIG. 2, the check valve 200 has a base 202, and each base 202 has a hollow cylindrical large diameter portion 204 and a small diameter portion 206. A circumferential groove is formed on the outer circumferential surface of the large diameter portion 204, and an O-ring 208 is fitted in the circumferential groove. The small diameter portion 206 is continuous and coaxial with the large diameter portion 204, and a casing 210 is fixed to the small diameter portion 206.

The casing 210 has a cylindrical shape and has a peripheral wall 212 and an end wall 214. The end wall 214 has a recess and a communication hole 216 in the center, and the end portion of the peripheral wall 212 opposite to the end wall 214 is airtightly fitted to the small diameter portion 206.
A cup-shaped valve body 218 is disposed in the casing 210, and the valve body 218 includes a disk-shaped plate portion 220 and a cylindrical portion 222 that is integrally connected to the outer peripheral edge of the plate portion 220. The cylindrical portion 222 is slidable with respect to the peripheral wall 212 of the casing 210, and a compression coil spring 224 is disposed between the plate portion 220 and the end wall 214 of the casing 210. The compression coil spring 224 biases the plate portion 220 toward the end surface of the small diameter portion 206 of the base 202.

  A plurality of openings 226 are formed at intervals in the circumferential direction on the base 202 side of the peripheral wall 212 of the casing 210. When the plate portion 220 of the valve body 218 is in contact with the end surface of the small diameter portion 206, the hollow portion of the base 202 and the opening 226 of the casing 210 are blocked by the valve body 218, but the plate portion 220 has a small diameter. When spaced apart from the end face of the portion 206, the hollow portion of the base 202 communicates with the opening 226 of the casing 210. That is, the end surface of the small diameter portion 206 forms a valve seat, and when the plate portion 220 of the valve body 218 is in contact with the end surface of the small diameter portion 206, the check valve 200 is closed and the plate portion 220 of the valve body 218 is closed. When the check valve 200 is separated from the end face of the small diameter portion 206, the check valve 200 is opened.

The plate portion 220 of the valve body 218 is subjected to the pressure Pin of the hollow portion of the base 202, the pressure Pout in the casing 210, and the urging force fs1 of the compression coil spring 224. When the difference between Pin and pressure Pout exceeds a predetermined set differential pressure ΔP1, the valve is opened. The set differential pressure ΔP1 is expressed by the following equation (1).
ΔP1 = Pin−Pout = fs1 / Sv1 (1)
Sv1 is an area (seal area) where pressure Pin acts on the plate portion 220 of the valve body 218 when the valve body 218 is in contact with the valve seat.

Accordingly, the discharge chamber 142 can communicate with the forward portion of the circulation path 12 via the discharge passage 156, the muffler space 154, the check valve 200, and the discharge port 152a. On the other hand, the suction chamber 140 communicates with the return path portion of the circulation path 12 via a suction port 104 a formed in the rear housing 104.
Note that the pressure on the discharge passage 156 side and the pressure on the discharge port 152a side as the pressure Pout act on the check valve 200 as the pressure Pin.

Referring to FIG. 1 again, the rear housing 104 accommodates a capacity control valve (electromagnetic control valve) 300, and the capacity control valve 300 is inserted in the air supply passage 160. The air supply passage 160 extends from the rear housing 104 to the cylinder block 101 through the valve plate 103 so as to communicate between the discharge chamber 142 and the crank chamber 105.
On the other hand, the suction chamber 140 communicates with the crank chamber 105 via the extraction passage 162. The extraction passage 162 includes a clearance between the drive shaft 106 and the bearings 119 and 120, a space 164, and a fixed orifice 103 c formed in the valve plate 103.

The suction chamber 140 is connected to the capacity control valve 300 independently of the air supply passage 160 through a pressure sensitive passage 166 formed in the rear housing 104.
More specifically, as shown in FIG. 3, the capacity control valve 300 includes a valve unit and a solenoid unit as an actuator that opens and closes the valve unit. The valve unit has a cylindrical valve housing 301, and an inlet port (valve hole 301 a) is formed at one end of the valve housing 301. The valve hole 301 a communicates with the discharge chamber 142 via the upstream portion of the air supply passage 160 and opens to the valve chamber 303 defined inside the valve housing 301.

A cylindrical valve body 304 is accommodated in the valve chamber 303. The valve body 304 can move in the valve chamber 303 in the axial direction of the valve housing 301, and can close the valve hole 301 a by contacting the end face of the valve housing 301. That is, the end surface of the valve housing 301 functions as a valve seat.
Further, an outlet port 301 b is formed on the outer peripheral surface of the valve housing 301, and the outlet port 301 b communicates with the crank chamber 105 through a downstream portion of the air supply passage 160. The outlet port 301b also opens into the valve chamber 303, and the discharge chamber 142 and the crank chamber 105 can communicate with each other through the valve hole 301a, the valve chamber 303, and the outlet port 301b.

  The solenoid unit has a cylindrical solenoid housing 310, and the solenoid housing 310 is coaxially connected to the other end of the valve housing 301. The open end of the solenoid housing 310 is closed by an end cap 312, and a cylindrical coil 316 surrounded by a resin member 314 is accommodated in the solenoid housing 310.

Further, a concentric cylindrical fixed core 318 is accommodated in the solenoid housing 310, and the fixed core 318 extends from the valve housing 301 toward the end cap 312 to the center of the coil 316. The end cap 312 side of the fixed core 318 is surrounded by a cylindrical member 320, and the cylindrical member 320 has a closed end on the end cap 312 side.
The fixed core 318 has an insertion hole 318 a at the center, and one end of the insertion hole 318 a opens into the valve chamber 303. In addition, a movable core housing space 324 for housing the cylindrical movable core 322 is defined between the fixed core 318 and the closed end of the cylindrical member 320, and the other end of the insertion hole 318 a is the movable core housing space 324. Is open.

  A solenoid rod 326 is slidably inserted into the insertion hole 318a, and a valve body 304 is integrally and coaxially connected to one end of the solenoid rod 326. The other end of the solenoid rod 326 projects into the movable core housing space 324, and the other end of the solenoid rod 326 is fitted into a through-hole formed in the movable core 322 so that the solenoid rod 326 and the movable core 322 are integrated. Has been. An open spring 328 is disposed between the stepped surface of the movable core 322 and the end surface of the fixed core 318, and a predetermined gap is secured between the movable core 322 and the fixed core 318.

The movable core 322, the fixed core 318, the solenoid housing 310, and the end cap 312 are made of a magnetic material and constitute a magnetic circuit. The cylindrical member 320 is made of a nonmagnetic stainless steel material.
A pressure-sensitive port 310 a is formed in the solenoid housing 310, and a suction chamber 140 is connected to the pressure-sensitive port 310 a through a pressure-sensitive passage 166. A pressure-sensitive groove 318b extending in the axial direction is formed on the outer peripheral surface of the fixed core 318, and the pressure-sensitive port 310a and the pressure-sensitive groove 318b communicate with each other.

Accordingly, the suction chamber 140 and the movable core housing space 324 communicate with each other through the pressure-sensitive port 310a and the pressure-sensitive groove 318b, and the suction chamber 140 is arranged in the valve closing direction on the back side of the valve body 304 via the solenoid rod 326. (Hereinafter referred to as suction pressure Ps). The integral structure of the valve body 304 and the solenoid rod 326 functions as a pressure sensitive member.
In the capacity control valve 300, preferably, the pressure receiving area (seal area Sv2) of the valve body 304 on which the pressure of the discharge chamber 142 (hereinafter referred to as the discharge pressure Pd) acts when the valve body 304 closes the valve hole 301a. The area of the valve body 304 on which the suction pressure Ps acts, that is, the cross-sectional area of the solenoid rod 326 is formed to be equal. In this case, the pressure of the crank chamber 105 (hereinafter referred to as crank pressure Pc) does not act on the valve body 304 in the opening / closing direction.

A control device 400 provided outside the compressor 100 is connected to the coil 316, and when the control current I is supplied from the control device 400 to the coil 316, the solenoid unit generates an electromagnetic force F (I). The electromagnetic force F (I) of the solenoid unit attracts the movable core 322 toward the fixed core 318 and acts on the valve body 304 in the valve closing direction.
Accordingly, the discharge pressure Pd, the suction pressure Ps, the electromagnetic force F (I), and the urging force fs2 of the compression coil spring act on the valve body 304, and the relationship among them is expressed by the following equations (2) and (3). Indicated.

Sv2 is an area (seal area) where the discharge pressure Pd acts on the valve body 304 through the valve hole 304a when the valve body 304 closes the valve hole 304a.
According to the equations (2) and (3), the Pd−Ps differential pressure ΔP (= Pd−Ps), which is the difference between the discharge pressure Pd and the suction pressure Ps, is an electromagnetic force F (I) generated in the solenoid unit. It can be adjusted. FIG. 4 shows the relationship between the control current I and the Pd-Ps differential pressure ΔP, and as the control current I increases, the Pd-Ps differential pressure ΔP increases. According to such a relationship, by operating the control current I, the discharge capacity is feedback-controlled so that the Pd−Ps differential pressure ΔP becomes a predetermined value. Such control is also referred to as Pd-Ps differential pressure control.

When the clutchless compressor 100 is to be deactivated, the control current I supplied to the coil 316 is set to zero. As a result, the valve element 304 is separated from the valve seat by the urging force of the release spring 328 and the valve hole 301a is opened. The refrigerant in the discharge chamber 142 is introduced into the crank chamber 105 through the capacity control valve 300, and the discharge capacity is kept to a minimum. The
The activation of the air conditioning system (air conditioner) or the compressor 100 means that the compressor 100 is changed from the non-operating state to the operating state, and that the compressor 100 is in the non-operating state means that the check valve 200 is closed. The state in which the refrigerant is not discharged from the compressor 100 to the outside. On the other hand, the compressor 100 being in an operating state refers to a state in which the check valve 200 is in an open state and refrigerant is discharged from the compressor 100 to the outside.

  The set differential pressure ΔP1 of the check valve 200 is set to be larger than the Pd−Ps differential pressure ΔP generated when the compressor 100 is in the mechanical minimum discharge capacity state, and the check valve 200 is normally closed in the minimum discharge capacity state. It is in. Since the minimum inclination angle of the swash plate 107 is substantially 0 °, the Pd−Ps differential pressure ΔP in the minimum discharge capacity state is small, and the set differential pressure ΔP1 of the check valve 200 is Pd− in the minimum discharge capacity state. The pressure is set to be slightly higher than the Ps differential pressure ΔP.

  Therefore, when the compressor 100 is in the mechanical minimum discharge capacity state, the flow of the refrigerant from the compressor 100 to the radiator 14 is blocked by the check valve 200. In the minimum discharge capacity state, the refrigerant discharged from the cylinder bore 101a to the discharge chamber 142 is upstream of the air supply passage 160, the capacity control valve 300, the downstream side of the air supply passage 160, the crank chamber 105, and the extraction passage 162. Then, the gas is again sucked into the cylinder bore 101a via the suction chamber 140. That is, the refrigerant circulates in the compressor 100 in the minimum discharge capacity state.

In the state where the check valve 200 is closed, the flow of refrigerant on the downstream side (the radiator 14 side) from the check valve 200 is eliminated. At this time, if the expansion valve 16 is in an open state, the refrigerant pressure Pout at the outlet of the check valve 200 is substantially equal to the suction pressure Ps. Even if the expansion valve 16 is closed, the pressure Pout approaches the suction pressure Ps due to valve leakage.
That is, when the check valve 200 is closed, it may be considered that the refrigerant pressure Pin at the inlet of the check valve 200 is equal to the discharge pressure Pd and the pressure Pout is equal to the suction pressure Ps. Therefore, when the clutchless compressor 100 is switched from the non-operating state to the operating state, that is, when the check valve 200 changes from the closed state to the open state, the Pd-Ps differential pressure ΔP is equal to the check valve 200. It can be considered that it is substantially equivalent to the set differential pressure ΔP1.

  As shown in FIG. 4, the usage range of the control current I used for capacity control is defined by a lower limit value Imin and an upper limit value Imax, except when it is zero. The lower limit value Imin corresponds to the minimum value (minimum differential pressure ΔPmin) of the Pd-Ps differential pressure ΔP in the controllable range, and the upper limit value Imax corresponds to the maximum value of the Pd-Ps differential pressure ΔP in the controllable range. (Maximum differential pressure ΔPmax) corresponds. Here, the lower limit value Imin is determined so that the minimum differential pressure ΔPmin becomes equal to the set differential pressure ΔP1 of the check valve 200.

  Thus, the lower limit value Imin is determined when the check valve 200 is closed and the flow of the refrigerant from the discharge chamber 142 to the radiator 14 is prevented when the clutchless compressor 100 is not in operation. This is because the Pd−Ps differential pressure ΔP cannot be brought close to a value equal to or less than the set differential pressure ΔP1 of 200. That is, with reference to the set differential pressure ΔP1 of the check valve 200, the minimum differential pressure ΔPmin, which is the minimum control limit of the Pd−Ps differential pressure ΔP, is defined, and the lower limit value Imin of the control current I corresponding to the minimum differential pressure ΔPmin. To the coil 316, the discharge capacity of the compressor 100 becomes the minimum minimum discharge capacity (effective minimum discharge capacity) as the operating state.

  However, the set differential pressure ΔP1 of the check valve 200 and the operation characteristics of the capacity control valve 300 shown by the equation (2) have production variations, respectively, and the minimum differential pressure ΔPmin and the lower limit value Imin of the control current I are different. Is preferably set in consideration of these variations. Defining the minimum differential pressure ΔPmin on the basis of the set differential pressure ΔP1 of the check valve 200 includes a case where these variations are taken into consideration.

Specifically, as shown in FIG. 5, if the minimum differential pressure ΔPmin varies within the range of ΔP1 ± α and the Pd−Ps differential pressure ΔP of the capacity control valve 300 varies within the range of ΔP ± β, the lower limit value of the control current I As Imin, it is conceivable to assume a range from IL through IM to IH.
FIG. 6 is a block diagram showing a schematic configuration of the capacity control system A including the control device 400. The capacity control system A includes an air conditioner switch 402, an evaporator target temperature setting unit 401, and a temperature sensor 403.

The evaporator target temperature setting means 401 can be constituted by, for example, a part of an air conditioner ECU (electronic control unit) that controls the operation of the entire air conditioning system. The control device 400 can be configured by an independent ECU, but may be configured by a part of the air conditioner ECU.
The air conditioner switch 402 is operated by an occupant, and the variable capacity compressor 100 is switched from the non-operating state to the operating state or from the operating state to the non-operating state by switching the air conditioner switch 402 to the on state or the off state.

  The evaporator target temperature setting means 401 is a means for setting the target cooling state of the evaporator 18, and the evaporator target outlet air temperature is based on various external information including the passenger compartment temperature setting set by the passenger. Set Tes. The evaporator target outlet air temperature Tes is a target of discharge capacity control of the compressor 100, and is a target value of the temperature of the air flow at the outlet of the evaporator 18 (evaporator outlet air temperature) Te.

The temperature sensor 403 is one of external information detection means, and detects the evaporator outlet air temperature Te in order to detect the cooling state of the evaporator 18. The temperature sensor 403 is installed at the outlet of the evaporator 18 in the air circuit (see FIG. 1).
The control device 400 includes a target differential pressure setting unit 404 and a solenoid driving unit 405, and the target differential pressure setting unit 404 sets a target differential pressure ΔPt. The target differential pressure ΔPt is a target value of Pd−Ps differential pressure ΔP, which is the difference between the discharge pressure Pd and the suction pressure Ps. As apparent from the above-described equation (3), since the Pd−Ps differential pressure ΔP is determined corresponding to the control current I supplied to the coil 316, setting the target differential pressure ΔPt is supplied to the coil 316. Equivalent to setting power control current I. That is, it can be said that the target differential pressure setting means 404 sets the control current I.

The solenoid driving unit 405 supplies the control current I set by the target differential pressure setting unit 404 to the coil 316 to drive the capacity control valve 300. The control current I is adjusted by changing the duty ratio by, for example, PWM (pulse width modulation) with a predetermined drive frequency (for example, 400 to 500 Hz).
That is, the target differential pressure setting unit 404 and the solenoid driving unit 405 adjust the control current I supplied to the coil 316 of the capacity control valve 300 or a parameter related to the control current I based on the target differential pressure ΔPt. Adjusting means is configured.

  Here, an evaporator target temperature setting means 401 and a temperature sensor 403 are electrically connected to the target differential pressure setting means 404, and the evaporator target outlet air temperature Tes and the evaporator outlet air temperature Te are at appropriate times. Entered at intervals. The target differential pressure setting means 404 sets the target differential pressure ΔPt or the control current I so as to reduce the difference between the evaporator target outlet air temperature Tes and the evaporator outlet air temperature Te as an air conditioning control mode according to the cooling load. Set.

However, the set differential pressure ΔP1 is also inputted in advance to the target differential pressure setting means 404, and the target differential pressure setting means 404 has the target outlet air temperature Tes and evaporation on the minimum side of the target differential pressure ΔPt or the control current I. The target differential pressure ΔPt or the control current I is set based on the outlet air temperature Te and the set differential pressure ΔP1.
That is, when the air conditioner switch is in the ON state, the target differential pressure ΔPt is set to be a value equal to or larger than the set differential pressure ΔP1 on the minimum side of the target differential pressure ΔPt. Alternatively, when the air conditioner switch is in the ON state, the control current I is set so that the target differential pressure ΔPt corresponding to the control current I is equal to or greater than the set differential pressure ΔP1 on the minimum side of the control current I.

Further, the target differential pressure setting means 404 preferably executes the start control mode when starting the compressor 100. In the activation control mode, the target differential pressure setting unit 404 sets the target differential pressure ΔPt or the control current I to the minimum value, and gradually increases from the minimum value.
For example, as shown in FIG. 7, the target differential pressure setting unit 404 sets and maintains the control current I at the initial value Is1 for a predetermined time t1 when the air conditioner switch 402 is switched from the off state to the on state. . Then, the target differential pressure setting means 404 increases the control current I from the initial value Is1 to the provisional value Is2 until the predetermined time t2.

Here, the initial value Is1 of the control current I is set as a minimum current at which the compressor 100 starts reliably. For example, referring to FIG. 5, Is1 is set to a current value slightly larger than IH.
Further, as shown in FIG. 8, the target differential pressure setting unit 404 may not maintain the initial value Is1. In this case, since the control current I gradually increases as time elapses from immediately after the air conditioner switch 402 is turned on to the predetermined time t2, even if the initial value Is1 is set to IL smaller than IH, the compressor 100 is ensured. Starts. However, the provisional value Is2 is set larger than IH.

  The target differential pressure setting means 404 ends the activation control mode at the same time as time t2 and shifts to the air conditioning control mode. In the air conditioning control mode, the target differential pressure setting unit 404 is configured so that the actual evaporator outlet air temperature Te detected by the temperature sensor 403 approaches the evaporator target temperature Tes set by the evaporator target temperature setting unit 401. A target differential pressure ΔPt that is a control target, that is, a control current I is calculated.

  In the capacity control system A described above, the control current I supplied to the coil 316 is adjusted based on the external information and the set differential pressure ΔP1 of the check valve 200. By considering the set differential pressure ΔP1 of the check valve 200, the discharge capacity control is accurately performed up to the effective minimum discharge capacity, and the discharge capacity control near the effective minimum discharge capacity becomes stable. In addition, the power consumption of the variable capacity compressor is reduced by accurately controlling the discharge capacity with the effective minimum discharge capacity.

  In the capacity control system A described above, the control current I supplied to the coil 316 is adjusted based on the target differential pressure ΔPt, which is the target value of the Pd−Ps differential pressure ΔP, so that the discharge capacity control range is wide. Further, by adjusting the control current I based on the set differential pressure ΔP1 of the check valve 200, the discharge capacity control is accurately performed up to the effective minimum discharge capacity, and the entire control range is effective. Be utilized.

  Further, according to the capacity control system A, when the variable capacity compressor 100 is switched from the non-operating state to the operating state, the initial value Is1 of the control current I is set based on the set differential pressure ΔP1 of the check valve 200. The Pd−Ps differential pressure ΔP is substantially minimized within the discharge capacity control range. For this reason, when the variable capacity compressor 100 is switched from the non-operating state to the operating state, a sudden increase in the driving load and the discharge pressure Pd of the variable capacity compressor 100 is suppressed, and power consumption is reduced and discharge is performed. Capacity control is stable.

Further, in the capacity control system A described above, the initial value Is1 of the control current I is set in consideration of one or both of the set differential pressure ΔP1 of the check valve 200 and the operation characteristics of the capacity control valve 200. Thus, the compressor 100 is reliably started.
Furthermore, according to the capacity control system A described above, the control load I supplied to the coil 316 gradually increases, so that the drive load and the discharge pressure Pd are maintained even after the variable capacity compressor 100 is in the operating state. The rapid increase of is suppressed. For this reason, in the air conditioning system to which the capacity control system A is applied, the air conditioning is smoothly performed after the variable capacity compressor 100 is in the operating state.

The present invention is not limited to the first embodiment described above, and various modifications can be made. Hereinafter, the capacity control system B according to the second embodiment will be described.
The capacity control system B can be applied to the compressor 100 and the capacity control valve 300, but the capacity control system B is different from the capacity control system A in several points as shown in FIG. Hereinafter, the capacity control system B will be described focusing on differences from the capacity control system A.

  The capacity control system B includes discharge pressure detection means as external information detection means. The discharge pressure detecting means includes a high pressure sensor 451 and a discharge pressure calculating means 452. The high pressure sensor 451 is installed on the inlet side of the radiator 14, for example, and detects the refrigerant pressure as the high pressure Ph at the inlet of the radiator 14. The high pressure sensor 451 can be installed in the high pressure region of the refrigeration cycle 10 from the discharge chamber 142 to the inlet of the expander 16.

The discharge pressure calculating means 452 calculates the discharge pressure Pd according to the following equation in consideration of the pressure difference ΔPd between the installation position of the high pressure sensor 451 and the discharge chamber 142.
Pd = Ph + ΔPd
If the check valve 200 is small there and heat load in the open state, the pressure difference ΔPd based on the pressure loss ΔPloss between the installation position of the discharge chamber 142 and the high-pressure sensor 451 is substantially the set differential pressure ΔP1 Since they can be regarded as equivalent, Pd = Ph + ΔP1.

Further, when the check valve 200 is in the closed state, the discharge pressure calculating means 452 detects the discharge pressure Pd in consideration of the set differential pressure ΔP1 as the pressure difference ΔPd. Specifically, as shown in the following equation, a predetermined value ΔP2 slightly larger than the sum of the set differential pressure ΔP1 and its variation α can be used as the pressure difference ΔPd.
Pd = Ph + ΔP2
The high pressure sensor 451 also serves as a thermal load detection means for calculating an initial value of the target suction pressure Pss.

Further, the control device 450 includes target suction pressure setting means 453 and control signal calculation means 454 instead of the target differential pressure setting means 404. Therefore, the target suction pressure setting means 453, the control signal calculation means 454, and the solenoid driving means 405 constitute a current adjusting means.
The target suction pressure setting means 453 sets the target suction pressure Pss. The target suction pressure Pss is a target value of the suction pressure Ps that is a control target. The target suction pressure setting means 453 appropriately sets the initial value of the target suction pressure Pss when there is a request for starting the compressor 100. Preferably, when starting the compressor 100, the target suction pressure setting means 453 sets an initial value of the target suction pressure Pss based on the heat load information. As the heat load information, the high pressure Ph can be used. Specifically, the initial value of the target suction pressure Pss is calculated by the following equation.

Pss = Ph−ΔP3
When the check valve 200 is closed, Ph = Ps, and the initial value of the target suction pressure Pss is set to a value slightly lower than the high pressure Ph by subtracting a predetermined value ΔP3.
After setting the initial value of the target suction pressure Pss, the target suction pressure setting means 453 is configured so that the evaporator target outlet air temperature Tes set by the evaporator target temperature setting means 401 and the evaporator outlet detected by the temperature sensor 403. The target suction pressure Pss can be set based on the air temperature Te. That is, the initial value is corrected so that the evaporator outlet air temperature Te approaches the evaporator target outlet air temperature Tes, and the air conditioning control mode is executed.

  However, it is preferable that the target suction pressure setting means 453 sets the target suction pressure Pss as the start control mode for a predetermined time after the compressor 100 is started. In the activation control mode, after the initial value of the target suction pressure Pss is set, the target suction pressure Pss is gradually lowered. After the start-up control mode is completed, the target intake is performed based on the evaporator target outlet air temperature Tes set by the evaporator target temperature setting means 401 and the evaporator outlet air temperature Te detected by the temperature sensor 403 as the air conditioning control mode. The pressure Pss is set.

The control signal calculation unit 454 calculates the control current I based on the discharge pressure Pd detected by the discharge pressure detection unit and the target suction pressure Pss set by the target suction pressure setting unit 453.
Specifically, the control current I is calculated by substituting the target suction pressure Pss and the discharge pressure Pd into the following formula (4). If the above equation (3) is modified, the following equation (4) is obtained, and if the solenoid unit is designed so that the electromagnetic force F (I) is substantially proportional to the control current I, then F (I) = A As I (where A is a constant), equation (4) becomes equation (5).

The target suction pressure Pss is substituted for the suction pressure Ps in the equation (5).
The control current I calculated by the equation (5) or the duty ratio corresponding to the control current I is input to the solenoid drive unit 405 as a discharge capacity control signal.
In the start control mode and the air conditioning control mode, the discharge capacity of the compressor 100 is controlled by adjusting the control current I supplied to the coil 316 of the capacity control valve 300 so that the suction pressure Ps approaches the target suction pressure Pss. The Such control is based on the relationship that the operation characteristic of the capacity control valve 300 is expressed by the above-described equation (5) and FIG. 10, and that the suction pressure Ps is determined if the discharge pressure Pd and the control current I are determined.

Hereinafter, an example of a program executed by the capacity control system B will be described as a method of using the capacity control system B.
FIG. 11 shows a main routine of the program. The main routine is activated when, for example, an engine key of the vehicle is turned on, and is stopped when the vehicle is turned off.
In the main routine, initial conditions are first set when starting (S100). Specifically, in S100, the flag F1, the flag F2, the measurement time t, and the control current I are set to zero.

Subsequently, it is determined whether or not the air conditioner switch 402 is on (S102). If the air conditioner switch 402 is on, the outputs (external information) of the evaporator target temperature setting means 401, the temperature sensor 403, and the high pressure sensor 451 are read (S104).
After S104, the target suction pressure Pss is set and the discharge pressure Pd is calculated in the target suction pressure setting / suction pressure calculation routine S108.

Thereafter, the control current I is calculated based on the discharge pressure Pd and the target suction pressure Pss (S110). That is, the control current I is calculated by substituting the discharge pressure Pd and the target suction pressure Pss into equation (5).
It is determined whether or not the control current I calculated in S110 is equal to or greater than a preset lower limit value Imin (S112). As a result of the determination in S112, when the calculated control current I is smaller than the lower limit value Imin (in the case of No), the lower limit value Imin is read as the control current value I (S114), and the control current I is converted to the coil 316. (S116).

  On the other hand, if the calculated control current I is equal to or greater than the lower limit value Imin as a result of the determination in S112 (Yes), the calculated control current I is compared with the upper limit value Imax that is larger than the preset lower limit value Imin. (S118). As a result of the determination in S118, if the control current value I exceeds the upper limit value Imax (in the case of No), the upper limit value Imax is read as the control current I (S120), and the control current I is output to the coil 316 ( S116).

Accordingly, if the control current I calculated in S110 is within the range indicated by Imin ≦ I ≦ Imax, it is output to the coil 316 as it is (S116). When the control current I is output, the program returns to S102.
The lower limit value Imin and the upper limit value Imax are set in the same manner as in the capacity control system B.

12 and 13 are flowcharts showing an outline of the target suction pressure setting / discharge pressure calculation routine S108.
In the target suction pressure setting / discharge pressure calculation routine S108, it is first determined whether or not the flag F1 is 0 (S152). Immediately after the air conditioner switch is turned on, the flag F1 is 0. Therefore, the determination result in S152 is always Yes, and it is determined whether or not the flag F2 is 0 (S154). Immediately after the air conditioner switch is turned on, the flag F2 is also 0, so that the determination result in S154 is always Yes and the initial value of the target suction pressure Pss is calculated (S156).

Specifically, the initial value of the target suction pressure Pss is obtained by subtracting the predetermined value ΔP3 from the high pressure Ph detected by the high pressure sensor 451.
Whether or not the initial value of the target suction pressure Pss calculated in S156 is equal to or higher than a preset lower limit value PssL is compared (S158), and whether or not it is equal to or lower than a preset upper limit value PssH. It is determined (S160). If the initial value of the target suction pressure Pss calculated in S156 is not less than the lower limit value PssL and not more than the upper limit value PssH, the initial value Pd0 of the discharge pressure Pd is calculated (S162).

Specifically, the initial value Pd0 of the discharge pressure Pd is obtained by adding a predetermined value ΔP2 to the high pressure Ph detected by the high pressure sensor 451. As described above, the predetermined value ΔP2 is slightly larger than the sum of the set differential pressure ΔP1 of the check valve 200 and its variation α.
The initial value Pd0 of the discharge pressure Pd calculated in S162 is read as the discharge pressure Pd (S164). Then, the timer is started and measurement of the measurement time t is started (S166) and the flag F2 is set to 1 (S168), and then the program returns to S110 of the main routine.

  Next, when the target suction pressure setting / discharge pressure calculation routine S108 is executed, since the flag F2 is set to 1 in S168, the determination result in S154 is No. Therefore, as shown in FIG. It is compared and determined whether or not the measurement time t is equal to or shorter than the predetermined time t2 (S170). The time t2 is set to, for example, 5 seconds or more and 30 seconds or less, and when the measurement time t is not more than the time t2, a new target suction pressure Pss is calculated by subtracting a predetermined value ΔP4 from the current target suction pressure Pss (S172). ). The predetermined value ΔP4 is a number set to gradually reduce the target suction pressure Pss.

  On the other hand, after returning to the main routine, until the next target suction pressure setting / discharge pressure calculation routine S108 is executed, the high pressure Ph is read again in S104, and the newly read high pressure Ph and pressure loss ΔPloss are read. It is compared and determined whether or not the sum is equal to or less than the initial value Pd0 of the discharge pressure Pd (S174). The pressure loss ΔPloss is a pressure loss between the installation position of the high pressure sensor 451 and the discharge chamber 142 when it is assumed that the check valve 200 is in the open state.

If the determination result in S174 is No, the sum of the high pressure Ph and the pressure loss ΔPloss is read as the discharge pressure Pd (S176). If the determination result in S174 is Yes, the discharge pressure Pd is maintained at the initial value Pd0. The
Whether or not the target suction pressure Pss calculated in S172 is equal to or higher than the lower limit value PssL is determined (S178). If the determination result in S178 is No, the lower limit value PssL is set to the target suction pressure Pss. If the determination result in S178 is Yes, whether or not the target suction pressure Pss calculated in S172 is equal to or lower than the upper limit value PssH is determined (S182). When the determination result in S182 is No, the upper limit value PssH is set to the target suction pressure Pss (S184). When the determination result in S182 is Yes, the target suction pressure Pss calculated in S172 is set as the target suction pressure Pss as it is.

Thus, when the target suction pressure Pss is set, the program returns to S110 of the main routine again.
If the measurement time t exceeds the time t2 while repeating the main routine and the target suction pressure setting / discharge pressure calculation routine S108, the determination result in S170 is No and the flag F1 is set to 1 (S186). Then, a deviation ΔT between the evaporator target outlet air temperature Tes and the evaporator outlet air temperature Te is calculated (S188), and the current target suction pressure Pss and deviation ΔT are substituted into a predetermined arithmetic expression for PI control, for example. A new target suction pressure Pss is calculated (S190).

The S190 calculation formula only needs to calculate the target suction pressure Pss so that the deviation ΔT is small. The subscript n of the deviation ΔT in this arithmetic expression indicates that the deviation ΔT has been calculated in the current S188. Similarly, the subscript n-1 indicates that the deviation ΔT has been calculated in the previous S188.
On the other hand, the sum of the high pressure Ph and the pressure loss ΔPloss is calculated and read as the discharge pressure Pd (S192).

  Then, similarly to the target suction pressure Pss calculated in S172, it is compared and determined whether or not the target suction pressure Pss calculated in S190 is equal to or lower than the upper limit value PssH (S182). When the determination result in S182 is No, the upper limit value PssH is set to the target suction pressure Pss (S184). When the determination result in S182 is Yes, the target suction pressure Pss calculated in S190 is set as the target suction pressure Pss as it is. When the target suction pressure Pss is set, the program returns to S110 of the main routine again.

  After the flag F1 is set to 1 in S186, the determination result in S152 becomes No until the air conditioner switch 402 is turned off, and S188, S190, and S192 are executed. When the air conditioner switch 402 is turned off, the determination result in S102 is No, and it is compared and determined whether the flag F1 is 1 or whether the flag F2 is 1 (S122).

When the flag F1 or the flag F2 is 1, the determination result in S122 of the main routine is Yes, and the flag F1, the flag F2, the measurement time t, and the control current I are set to 0 (S124). After S124, the control current I is output to the coil 316 in S116, but the output control current I is zero.
On the other hand, when the flag F1 and the flag F2 are 0, the determination result in S122 is No, and the control current I is output to the coil 316 in S116. When the flag F1 and the flag F2 are 0, the control current I is set to 0, and the control current I output to the coil 316 is 0 regardless of the determination result of S122. That is, when the air conditioner switch 402 is turned off, the compressor 100 is deactivated.

In the above-described target suction pressure setting / discharge pressure calculation routine S108, if the determination results in S158 and S160 are No, the program proceeds to S116 of the main routine, and zero is output as the control current I. That is, in this case, the compressor 100 is maintained in a non-operating state.
In the capacity control system B described above, since the control current I is calculated based on the equation (5), the discharge capacity of the compressor 100 is controlled so that the suction pressure Ps approaches the target suction pressure Pss.

  Then, the control device 450 executes the air conditioning control mode after executing the activation control mode for a predetermined time t2 after the air conditioning switch 402 is turned on. According to the start control mode, when the compressor 100 is started, the initial value of the target suction pressure Pss is calculated based on an arithmetic expression using the high pressure Ph when the compressor 100 is in an inoperative state as a variable. Then, the target suction pressure Pss is gradually lowered from the initial value with the passage of time. In the air conditioning control mode, a deviation ΔT between the evaporator target outlet air temperature Tes and the actual evaporator outlet air temperature Te is calculated, and the target suction pressure Pss is calculated so that the deviation ΔT is reduced.

  In the capacity control system B described above, the control range of the discharge capacity is wide by adjusting the control current I supplied to the coil 316 based on the discharge pressure Pd and the target suction pressure Pss. Further, by adjusting the control current I based on the set differential pressure ΔP1 of the check valve 200, the discharge capacity control is accurately performed up to the effective minimum discharge capacity, and the entire control range is effective. Be utilized.

And in the capacity | capacitance control system B mentioned above, the suction pressure Ps when the compressor 100 is a non-operation state is detected or estimated by utilizing the thermal load detected by the thermal load detection means. Thereby, in this capacity control system B, the initial value of the target suction pressure Pss is set easily and accurately.
Further, according to the capacity control system B described above, a part of the discharge pressure detection means also serves as the thermal load detection means, so that it is not necessary to newly add a thermal load detection means, and the configuration is simplified.

  Furthermore, according to the capacity control system B described above, the high-pressure pressure sensor 451 detects the high-pressure pressure Ph when the check valve 200 is closed, so that the suction can be performed when the variable-capacity compressor 100 is in an inoperative state. The pressure Ps is substantially detected. Then, by setting the initial value of the target suction pressure Pss based on the detected high pressure Ph, the initial value of the target suction pressure Pss is accurately set to a value close to the current suction pressure Ps.

As a result, according to the capacity control system B, when the variable capacity compressor 100 is started from the non-operating state to the operating state, the driving load and the discharge pressure Pd of the variable capacity compressor 100 are rapidly increased. Is suppressed, power consumption is reduced, and discharge capacity control is stabilized.
Furthermore, according to the capacity control system B, the target suction pressure is gradually decreased, so that a sudden increase in the driving load and the discharge pressure Pd is suppressed even after the variable capacity compressor 100 is in an operating state. . For this reason, in the air conditioning system to which the capacity control system B is applied, the air conditioning is smoothly performed after the variable capacity compressor 100 is in the operating state.

Further, according to the capacity control system B, the operation of the variable capacity compressor 100 in the region where the operation of the variable capacity compressor 100 is to be restricted is avoided, and the reliability of the variable capacity compressor 100 is ensured.
On the other hand, in the first capacity control system A and the capacity control system B described above, the variable capacity compressor 100 is a reciprocating variable capacity compressor having a swash plate element, and the mechanical variable range of the discharge capacity is wide. A wide variable range is used effectively.

Further, in the capacity control system A and the capacity control system B, the clutchless compressor 100 is often used together with the check valve 200, and the clutchless compressor 100 can be simplified without adding the check valve 200 anew. Applies to
In the first embodiment and the second embodiment described above, the set differential pressure ΔP1 of the check valve 200 is set larger than the Pd−Ps differential pressure ΔP generated in the mechanically specified minimum discharge capacity state, and the minimum discharge is set. Although the check valve 200 is always closed in the capacity state, the check valve 200 does not need to be always closed in the minimum discharge capacity state. The Pd-Ps differential pressure ΔP generated in the minimum discharge capacity state increases as the rotational speed of the compressor 100 increases. For example, the check valve 200 is closed at a predetermined rotational speed or less, and exceeds the predetermined rotational speed. In the region, the set differential pressure ΔP1 may be set so that the check valve 200 is slightly opened.

  In the first embodiment and the second embodiment described above, as shown in FIG. 5, there are variations in the set differential pressure ΔP1 of the check valve 200 and the characteristics of the capacity control valve 300. It is preferable to include not only the initial variation immediately after the assembly of the displacement control valve 300 but also the change in characteristics over time that occurs while the check valve 200 and the displacement control valve 300 are being used.

In the first embodiment and the second embodiment described above, in order to reduce variation in the characteristics of the capacity control valve 300 in the vicinity of the lower limit value Imin of the control current I, the characteristic adjustment when the capacity control valve 300 is assembled is adjusted to the lower limit value Imin. It is preferable to carry out in the vicinity.
In the startup control mode of the capacity control system A of the first embodiment, as shown in FIGS. 7 and 8, the control current I increases in proportion to time, but in the startup control mode, the control current I gradually increases. What is necessary is just to increase nonlinearly.

Similarly, in the startup control mode of the capacity control system B of the second embodiment, as shown in FIG. 14, the target suction pressure Pss decreases in proportion to the time, but in the startup control mode, the target suction pressure Pss decreases. What is necessary is just to reduce gradually and may reduce nonlinearly.
In the capacity control system B of the second embodiment, the high pressure sensor 451 of the discharge pressure detection means also serves as the thermal load detection means, but the thermal load detection means is not limited to this. For example, as the thermal load detection means, an outside air temperature sensor that detects the outside air temperature may be used. In this case, the initial value of the target suction pressure Pss may be set by an arithmetic expression using the outside air temperature as a variable. Further, as the thermal load detection means, a low pressure sensor that detects the pressure in the low pressure region of the refrigeration cycle 10, a temperature sensor that detects the temperature of each part in the vehicle interior, a temperature sensor that detects the refrigerant temperature, and the like can be used.

  In the example of the second embodiment, the high pressure sensor 451 is installed on the inlet side of the radiator 14. However, for example, the high pressure sensor 451 may be installed in the compressor 100 and directly detect the discharge pressure Pd in the discharge chamber 142. . In this case, since the discharge chamber 142 is located upstream of the check valve 200, the high pressure sensor 451 can always directly detect the discharge pressure Pd, but cannot directly detect the suction pressure Ps. Therefore, when calculating the initial value of the target suction pressure Pss, for example, a value obtained by subtracting ΔP5 slightly exceeding the upper limit value ΔP1 + α of the set differential pressure ΔP1 of the check valve 200 from the discharge pressure Pd when the air conditioner is off. May be the initial value of the target suction pressure Pss.

In the first embodiment and the second embodiment, the discharge pressure Pd and the suction pressure Ps act on the valve body 304 of the capacity control valve 300. However, the crank pressure Pc may further act.
In the first embodiment and the second embodiment, the compressor 100 is a clutchless compressor, but the compressor 100 may be a variable capacity compressor equipped with an electromagnetic clutch.

  Further, although the compressor 100 is a swash plate type, it may be a swing plate type, a vane type or a scroll type. Further, the compressor 100 may be a variable capacity compressor driven by an electric motor. That is, the compressor 100 may be a variable capacity compressor that operates the variable capacity mechanism by changing the pressure in the control pressure chamber. In a reciprocating variable displacement compressor having a swash plate or a swing plate as a swash plate type or swing plate type swash plate element, the pressure in the control pressure chamber is the pressure in the crank chamber.

In the first embodiment and the second embodiment, although the fixed orifice 103c is provided in the extraction passage 162, a flow rate variable throttle may be provided, or a valve capable of adjusting the valve opening degree may be provided.
In 1st Embodiment and 2nd Embodiment, a refrigerant | coolant is not limited to R134a or a carbon dioxide, You may use another new refrigerant | coolant.

  Finally, the capacity control system of the variable capacity compressor of the present invention is applicable to air conditioning systems in general, such as indoor air conditioning systems other than vehicle air conditioning systems.

It is a figure which shows schematic structure of the refrigerating cycle of a vehicle air conditioning system with the longitudinal cross-section of a variable capacity compressor. It is a figure which shows the non-return valve attached to the variable capacity compressor of FIG. 1, A left half is a side view, A right half is sectional drawing. It is a figure for demonstrating the connection state of the capacity | capacitance control valve in the variable capacity compressor of FIG. FIG. 4 is a graph for explaining a relationship between a control current I and a Pd−Ps differential pressure ΔP in the capacity control valve of FIG. 3. 5 is a graph for explaining the relationship between the control current I and the variation in the set differential pressure ΔP1 of the check valve and the variation in the Pd−Ps differential pressure ΔP in the graph of FIG. It is a block diagram which shows schematic structure of the capacity | capacitance control system of the variable capacity compressor of 1st Embodiment. It is a graph for demonstrating an example of the time change of the control electric current supplied to the coil of a capacity | capacitance control valve by the capacity | capacitance control system of FIG. It is a graph for demonstrating the other example of the time change of the control current supplied to the coil of a capacity | capacitance control valve by the capacity | capacitance control system of FIG. It is a block diagram which shows schematic structure of the capacity | capacitance control system of the variable capacity compressor of 2nd Embodiment. 10 is a graph for explaining a relationship among a control current, a target suction pressure, and a discharge pressure in the capacity control system of FIG. 9. 10 is a control flowchart showing a main routine executed by the capacity control system of FIG. 9. 12 is a part of a control flowchart of a target suction pressure setting / discharge pressure calculation routine included in the main routine of FIG. FIG. 12 is a remainder of a control flowchart of a target suction pressure setting / discharge pressure calculation routine included in the main routine of FIG. 11. 10 is a graph for explaining an example of a temporal change in a target suction pressure set by the capacity control system of FIG. 9.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Variable capacity compressor 200 Check valve 300 Capacity control valve 304 Valve body 316 Coil 401 Evaporator target temperature setting means 402 Air-conditioner switch 403 Temperature sensor (external information detection means)
404 Target differential pressure setting means (current adjusting means)
405 Solenoid driving means (current adjusting means)
451 High pressure sensor (external information detection means)
452 Discharge pressure calculation means (external information detection means)
410 Target suction pressure setting means (current adjusting means)
454 Control signal calculation means (current adjustment means)

Claims (14)

In a capacity control system of a variable capacity compressor that is inserted together with a radiator, an expander and an evaporator in a circulation path through which a refrigerant circulates to constitute a refrigeration cycle, and whose capacity changes based on a change in control pressure,
A check valve provided between the variable capacity compressor and the radiator in the circulation path and opened at a predetermined differential pressure;
A valve in which the pressure in the discharge pressure region of the variable capacity compressor acts, and the pressure in the suction pressure region of the variable capacity compressor and the electromagnetic force of the solenoid unit act in a direction opposite to the pressure in the discharge pressure region. A displacement control valve that has a body and changes the control pressure by the operation of the valve body;
External information detection means for detecting at least one external information;
Variable capacity compression comprising: current adjusting means for adjusting current supplied to the coil of the solenoid unit based on external information detected by the external information detecting means and a set differential pressure of the check valve Capacity control system.   The lower limit value of the current supplied to the coil by the current adjusting means is set such that the differential pressure between the pressure in the discharge pressure region and the pressure in the suction pressure region exceeds the set differential pressure of the check valve. The capacity control system for a variable capacity compressor according to claim 1, wherein The external information detection means includes discharge pressure detection means for detecting the pressure in the discharge pressure region,
The current adjusting means includes target suction pressure setting means for setting a target suction pressure that is a target value of the pressure in the suction pressure region based on the external information detected by the external information detection means, and the discharge pressure Adjusting the current supplied to the coil based on the pressure in the discharge pressure region detected by the detection means, the target suction pressure set by the target suction pressure setting means, and the set differential pressure of the check valve. The capacity control system for a variable capacity compressor according to claim 1 or 2, characterized in that: The external information detection means includes a heat load detection means for detecting a heat load of the refrigeration cycle,
The target suction pressure setting means is detected by the thermal load detecting means when the variable capacity compressor is in an inoperative state when the variable capacity compressor is requested to be in an inoperative state. 4. The capacity control system for a variable capacity compressor according to claim 3, wherein an initial value of the target suction pressure is set based on the heat load that is made. The discharge pressure detection means also serves as the thermal load detection means,
The target suction pressure setting means is based on a pressure in the discharge pressure region detected by the discharge pressure detection means or a value related to the pressure detected by the discharge pressure detection means when the variable capacity compressor is in an inoperative state. 5. The capacity control system for a variable capacity compressor according to claim 4, wherein an initial value of the suction pressure is set. The discharge pressure detection means includes a pressure sensor that is installed downstream from the check valve and detects a pressure in the high pressure region of the refrigeration cycle as a value related to the pressure in the discharge pressure region.
The target suction pressure setting means is configured to detect an initial target suction pressure based on a pressure in the high pressure region detected by the pressure sensor when the variable capacity compressor is in an inoperative state and the check valve is closed. 6. The capacity control system for a variable capacity compressor according to claim 5, wherein a value is set.   7. The capacity control system for a variable capacity compressor according to claim 4, wherein the target suction pressure setting means gradually decreases the target suction pressure from the initial value.   The variable capacity compressor is maintained in a non-operating state when an initial value of the target suction pressure is less than a preset lower limit value or exceeds a preset upper limit value. The capacity control system of the variable capacity compressor according to any one of 3 to 6.   The current adjusting means sets a target differential pressure that is a target value of a differential pressure between the pressure in the discharge pressure area and the pressure in the suction pressure area based on the external information detected by the external information detecting means. A differential pressure setting means is included, and a current supplied to the coil is adjusted based on a target differential pressure set by the target differential pressure setting means and a set differential pressure of the check valve. Item 3. A capacity control system for a variable capacity compressor according to Item 1 or 2.   When the variable capacity compressor is switched from the non-operating state to the operating state, the initial value of the current supplied to the coil by the current adjusting means is set based on the set differential pressure of the check valve. The capacity control system for a variable capacity compressor according to claim 9, wherein the capacity control system is a variable capacity compressor.   The initial value of the current is set in consideration of one or both of a set differential pressure of the check valve and an operating characteristic of the capacity control valve so that the variable compressor is reliably started. The capacity control system for a variable capacity compressor according to claim 10.   12. The capacity control system for a variable capacity compressor according to claim 10, wherein the current adjusting means gradually increases a current supplied to the coil from the initial value. )
The variable capacity compressor is:
A housing in which the discharge pressure region, the crank chamber, the suction pressure region, and the cylinder bore are defined;
A piston disposed in the cylinder bore;
A drive shaft rotatably supported in the housing;
A conversion mechanism including a variable swash plate element that converts rotation of the drive shaft into reciprocating motion of the piston;
An air supply passage communicating the discharge chamber and the crank chamber;
A bleed passage for communicating the crank chamber and the suction chamber;
The capacity control system for a variable capacity compressor according to any one of claims 1 to 12, wherein the capacity control valve is inserted in the air supply passage.   14. The capacity control system for a variable capacity compressor according to claim 13, wherein the variable capacity compressor is a clutchless compressor.

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