JP2010038062A - Control system of variable displacement compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system for accurately controlling a variable displacement compressor by a displacement control valve by optimizing the system according to the variation of characteristics of the variable displacement compressor or the displacement control valve by a simple configuration. <P>SOLUTION: The control system (A) of a variable displacement compressor includes: a first control device (400A) for setting the target value of a control amount according to at least one external information; a second control device (400B) for calculating a standard operation amount according to the target value of the control amount; and a third control device (400C) formed separately from the first control device (400A). The third control device (400C) corrects the standard operation amount according to the variation of the characteristics of the variable displacement compressor (100) and/or the displacement control valve (200), and based on the corrected operation amount, adjusts a drive current supplied to the coil (254) of a solenoid unit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  For example, a reciprocating variable displacement compressor used in a vehicle air conditioning system includes a housing, and a discharge chamber, a suction chamber, a crank chamber, and a cylinder bore are defined in the housing. 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, becomes variable by changing the pressure (control pressure) of the crank chamber, and in order to control the discharge capacity, an air supply passage that connects the discharge chamber and the crank chamber is used. A capacity control valve is disposed, and a throttle is disposed in a bleed passage that connects the crank chamber and the suction chamber.
For example, the capacity control valve disclosed in Patent Document 1 has a built-in pressure-sensitive member for sensing suction pressure. In a variable capacity compressor using this capacity control valve, feedback control is performed on the discharge capacity by sensing the suction pressure. To do. Specifically, the pressure-sensitive member is made of, for example, a bellows, and expands to decrease the discharge capacity when the suction pressure decreases, thereby increasing the opening of the air supply passage.

Further, in the capacity control method of the variable capacity compressor disclosed in Patent Document 2, capacity control is performed so that the pressure difference between the two pressure monitoring points approaches the target value.
Furthermore, the capacity control device disclosed in Patent Document 3 feedback-controls the discharge capacity so that the pressure difference (differential pressure) between the pressure in the discharge chamber (discharge pressure) and the pressure in the suction chamber approaches the target value. . That is, the control device of Patent Document 3 changes the energization amount to the coil of the capacity control valve using the differential pressure as a control target, and the discharge capacity changes accordingly. For example, if the differential pressure is to be reduced, this control device operates to increase the discharge capacity and bring the differential pressure closer to a predetermined value.

  Similarly to the capacity control method disclosed in Patent Document 2, the differential pressure control executed by the capacity control device of Patent Document 3 is considered to belong to the one that brings the pressure difference between the two pressure monitoring points closer to the target value. Therefore, the capacity control device of the variable capacity compressor has a suction pressure control system that controls the suction pressure as represented by Patent Document 1 and a differential pressure as represented by Patent Documents 2 and 3. It is roughly divided into those of the differential pressure control system to be controlled.

When the techniques disclosed in Patent Documents 1 to 3 are used, a dedicated control device is required for the variable capacity compressor. The control device for the variable capacity compressor is usually provided integrally with the control device of the air conditioning system.
The control device of the air conditioning system sets a target value for the control amount based on external information detected by a sensor or the like. The control device for the variable capacity compressor adjusts the drive current flowing through the coil so that the control amount approaches the target value.
JP-A-9-268973 JP 2001-107854 A JP 2001-132650 A

Each of the variable capacity compressor and the capacity control valve has manufacturing variations. For this reason, even if the same target value (control command value) is input from the control device of the air conditioning system to the control device for the variable capacity compressor, the control amount varies. That is, in Patent Document 1, the suction pressure control characteristics vary, and in Patent Documents 2 and 3, the differential pressure control characteristics vary.
If the variation is large, the control range may change greatly for each variable capacity compressor. As a result, the target control amount may not be obtained on the upper limit side or lower limit side of the drive current that is the operation amount.

  Also, a control characteristic that is a standard representing a control characteristic of a capacity control valve of the same specification is usually determined, and this is reflected as a function of drive current in a control program of a control device for a variable capacity compressor. . If the relationship between the input (drive current) to the capacity control valve and the output (suction pressure, differential pressure, etc.) greatly deviates due to manufacturing variations, there is a problem that the control accuracy is deteriorated in a normal control program.

The problems as described above are caused by the fact that the variable capacity compressor and the capacity control valve as control targets are separated from the control apparatus for the variable capacity compressor. That is, the control device for the variable capacity compressor is provided in the control device for the air conditioning system, and the control device for the variable capacity compressor is not optimized for each variable capacity compressor or capacity control valve.
The present invention has been made based on the above-mentioned circumstances, and the object thereof is optimized in accordance with the variation in the characteristics of the variable capacity compressor or the capacity control valve with a simple configuration, and the variable capacity is set via the capacity control valve. An object is to provide a system for accurately controlling a compressor.

  In order to achieve the above object, according to the present invention, the present invention is applied to discharge capacity control of a variable capacity compressor through an electromagnetic control valve having a valve body to which a pressure of a working fluid and a load from a solenoid unit are applied. In a control system for a variable displacement compressor, a first control device that sets a target value of a control amount based on at least one external information, and a standard operation amount is calculated based on the target value of the control amount A third control device provided separately from the second control device and the first control device, wherein the standard control unit is based on a variation in characteristics of at least one of the variable capacity compressor and the capacity control valve. And a third control device for correcting a drive current supplied to the coil of the solenoid unit based on the corrected operation amount, and controlling the variable capacity compressor Stem is provided (claim 1).

Preferably, the manipulated variable is a current value of the drive current.
Preferably, the second control device calculates the standard operation amount based on a target value of the control amount and at least one external information, and the second control device and the third control device are A single control unit is provided as a single unit.
Preferably, the control unit includes an input unit for inputting a signal related to an operation amount for correction to the third control device from the outside when determining a correction amount for correcting the variation in characteristics. Item 4).

Preferably, the variation in characteristics is a variation in the relationship between the operation amount and the pressure of the working fluid based on individual differences of the variable capacity compressor or the capacity control valve.
Preferably, the first control device includes a correction amount determination unit, and the correction amount determination unit determines a correction amount for correcting the variation in the characteristics by an external operation, and the determined correction amount Is provided to the third control device. (Claim 6)

  Preferably, the third control device is fixed to one of the variable capacity compressor and the capacity control valve.

  In the variable capacity compressor control system according to the first aspect of the present invention, the first control device for setting the target value of the control amount and the third control device for adjusting the drive current are provided separately, and the third control device. However, the standard operation amount calculated by the second control device is corrected based on the variation in the characteristics of at least one of the variable displacement compressor and the displacement control valve. As described above, by providing the third control device with a function of correcting the standard operation amount, the third control device is optimized in accordance with the variation in characteristics. This optimization is easy because the first control device and the third control device are separate. Then, by optimizing the third control device, according to this control system, the discharge capacity of the variable capacity compressor is accurately controlled via the capacity control valve.

In the control system for the variable capacity compressor according to the second aspect, the discharge capacity of the variable capacity compressor is accurately controlled with a simpler configuration by correcting the current value of the drive current as the operation amount.
In the control system for the variable capacity compressor according to the third aspect, the second control device calculates a standard operation amount based on the target value of the control amount and external information. For this reason, the drive current is accurately adjusted by the third control device regardless of the type of control amount set by the first control device.

In addition to being able to select and set an appropriate control amount from various physical quantities for the first control device, the second control device and the third control device are integrated, The versatility or commonality of one control device is increased.
In the control system for the variable capacity compressor according to the fourth aspect, the operation amount for correction can be input from the outside to the control unit, so that the correction amount can be easily determined.

  In the control system for the variable displacement compressor according to the fifth aspect, the operation amount is corrected based on the variation in the relationship between the operation amount based on the individual difference of the variable displacement compressor or the displacement control valve and the pressure of the working fluid. Variations in the relationship between the manipulated variable and the pressure of the working fluid based on individual differences in variable displacement compressors or displacement control valves have a large effect on control accuracy. This control system ensures reliable control accuracy. Get higher. That is, according to this control system, the control amount can be brought close to the target value with high accuracy.

In the control system for the variable capacity compressor according to the sixth aspect, by using the correction amount determining means of the first control device, it is possible to determine the correction amount and to input the determined correction amount to the third control device. For this reason, it is easy to determine and input the correction amount even after the control system is assembled to the vehicle, for example. Furthermore, it becomes easy to determine the failure of the variable capacity compressor.
In the variable displacement compressor control system according to the seventh aspect, the third control device is fixed to the variable displacement compressor or the displacement control valve. If this fixing operation is performed at the factory, the optimization operation of the third control device can be easily performed at the factory, and a large number of third control devices can be optimized in a short time.

Hereinafter, the control system A of the variable capacity compressor of the first embodiment of the present invention will be described.
FIG. 1 shows a refrigeration cycle 10 of a vehicle air conditioning system to which a control system A is applied. The refrigeration cycle 10 includes a circulation path 12 through which a refrigerant as a working fluid circulates. In the circulation path 12, the compressor 100, the radiator (condenser or gas cooler) 14, the expander 16, and the evaporator 18 are sequentially inserted in the flow direction of the refrigerant, and when the compressor 100 is activated, the compressor 100 The refrigerant circulates through the circulation path 12 in accordance with the discharge capacity of the refrigerant.

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 radiator 14 has a function of cooling the refrigerant discharged from the compressor 100, and the cooled refrigerant is expanded by passing through the expander 16. The expanded refrigerant is vaporized in the evaporator 18, and the vaporized refrigerant is sucked into the compressor 100.

The evaporator 18 also constitutes a part of the 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. As the cooled air flow flows into the passenger compartment, the passenger compartment is cooled or dehumidified.
The compressor 100 to which the control system A is applied is a variable capacity compressor, for example, a 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.

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 a pulley of an 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 140 and a discharge chamber 142 are defined in the rear housing 104, and the suction chamber 140 can communicate with the cylinder bore 101 a through a suction hole 103 a provided in the valve plate 103. 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 170 is disposed in the muffler space 154 so as to block between the discharge passage 156 and the discharge port 152a. Specifically, the check valve 170 opens and closes according to the pressure difference between the pressure on the discharge passage 156 side and the pressure on the muffler space 154 side, and closes when the pressure difference is smaller than a predetermined value, and the pressure difference is predetermined. If it is larger than the value, it opens.

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, and the discharge port 152a, and the muffler space 154 is intermittently connected by the check valve 170. 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.
A capacity control valve (electromagnetic control valve) 200 is accommodated in the rear housing 104, and the capacity control valve 200 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 200 independently of the air supply passage 160 through a pressure sensitive passage 166 formed in the rear housing 104.

The capacity control valve 200 controls the amount of refrigerant introduced into the crank chamber 105 by opening the opening of the air supply passage 160 that connects the discharge chamber 142 and the crank chamber 105. On the other hand, the refrigerant in the crank chamber 105 flows into the suction chamber via the extraction passage 162.
Therefore, the discharge capacity can be controlled by adjusting the amount of refrigerant introduced into the crank chamber 105 via the capacity control valve 200 and changing the pressure in the crank chamber 105.

  More specifically, as shown in FIG. 2, the capacity control valve 200 includes a valve unit and a drive unit (solenoid unit). The valve unit has a cylindrical valve housing 202, and a valve hole 204 is formed inside the valve housing 202. The valve hole 204 extends in the axial direction of the valve housing 202, and one end of the valve hole 204 is connected to the outlet port 206. The outlet port 206 passes through the valve housing 202 in the radial direction, and the valve hole 204 communicates with the crank chamber 105 via the outlet port 206 and the downstream portion of the air supply passage 160.

  A valve chamber 208 is defined on the solenoid unit side of the valve housing 202, and the other end of the valve hole 204 opens at the end wall of the valve chamber 208. A substantially cylindrical valve body 210 is accommodated in the valve chamber 208, and the valve body 210 can move in the axial direction of the valve housing 202 in the valve chamber 208. When one end of the valve body 210 abuts against the end wall of the valve chamber 208, the valve body 210 can close the valve hole 204, and the end wall of the valve chamber 208 functions as a valve seat.

  An inlet port 212 is formed in the valve housing 202, and the inlet port 212 also penetrates the valve housing 202 in the radial direction. The inlet port 212 communicates with the discharge chamber 142 through the upstream portion of the air supply passage 160. The inlet port 212 opens at the peripheral wall of the valve chamber 208, and the discharge chamber 142 and the crank chamber 105 can communicate with each other through the inlet port 212, the valve chamber 208, the valve hole 204, and the outlet port 206.

  Furthermore, a pressure sensitive chamber 214 is defined in the valve housing 202 on the side opposite to the solenoid unit, and a pressure sensitive port 216 is formed on the peripheral wall of the pressure sensitive chamber 214. The pressure sensing chamber 214 communicates with the suction chamber 140 through the pressure sensing port 216 and the pressure sensing passage 166. An axial hole 218 is provided between the pressure sensitive chamber 214 and the valve hole 204, and the axial hole 218 extends coaxially with the valve hole 204.

  A pressure sensitive rod 220 is integrally and coaxially connected to the other end of the valve body 210. The pressure sensitive rod 220 extends through the valve hole 204 and the axial hole 218, and the tip of the pressure sensitive rod 220 protrudes into the pressure sensitive chamber 214. The pressure-sensitive rod 220 has a large-diameter portion on the distal end side, and the large-diameter portion of the pressure-sensitive rod 220 is slidably supported by the inner peripheral surface of the axial hole 218. Therefore, the airtightness between the pressure sensitive chamber 214 and the valve hole 204 is ensured by the large diameter portion of the pressure sensitive rod 220.

The end wall of the pressure sensitive chamber 214 is formed by a cap 222 that is press-fitted into the end of the valve housing 202, and the cap 222 has a stepped bottomed cylindrical shape. A cylindrical portion of the support member 224 is slidably fitted to the small diameter portion of the cap 222, and a forced release spring 226 is disposed between the bottom wall of the cap 222 and the support member 224.
A pressure sensor 228 is accommodated in the pressure sensing chamber 214, and one end of the pressure sensor 228 is fixed to the support member 224. Therefore, the cap 222 supports the pressure sensor 228 via the support member 224.

  The pressure sensor 228 has a bellows 230, and the bellows 230 can expand and contract in the axial direction of the valve housing 202. Both ends of the bellows 230 are hermetically closed by caps 232 and 234, and the inside of the bellows 230 is kept in a vacuum state (depressurized state). In addition, a compression coil spring 236 is disposed inside the bellows 230, and the compression coil spring 236 biases the caps 232 and 234 away from each other so that the bellows 230 extends.

The cap 234 of the pressure sensor 228 can be brought into contact with the pressure sensing rod 220 via the adapter 238. When the pressure in the pressure sensing chamber 214 decreases and the pressure sensing device 228 extends, the pressure sensing rod 228 extends through the pressure sensing rod 220. The valve body 210 is urged in the valve opening direction.
Note that the amount of press-fitting of the cap 222 to the valve housing 202 is adjusted so that the displacement control valve 200 performs a predetermined operation.

  On the other hand, the solenoid unit includes a substantially cylindrical solenoid housing 240 coaxially connected to the valve housing 202, and a substantially cylindrical fixed core 242 is disposed concentrically within the solenoid housing 240. One end portion of the fixed core 242 is fitted to the end portion of the valve housing 202 to partition the valve chamber 208 and supports the valve body 210 slidably.

  A bottomed sleeve 244 is fitted into a portion extending from the center to the other end of the fixed core 242. A core housing space 246 is defined between the bottom wall of the sleeve 244 and the other end of the fixed core 242, and a movable core 248 is disposed in the core housing space 246. The movable core 248 is slidably supported by the sleeve 244 and can reciprocate in the axial direction of the solenoid housing 240.

  One end of a solenoid rod 250 extending in the fixed core 242 contacts the other end of the valve body 210, and the other end of the solenoid rod 250 is fixed integrally with the movable core 248. Therefore, the valve body 210 moves in the valve closing direction in conjunction with the movable core 248. A compression coil spring 252 is disposed between the movable core 248 and the bottom wall of the sleeve 244, and the compression coil spring 252 always urges the valve body 210 in the valve closing direction via the movable core 248 and the solenoid rod 250. To do.

  A cylindrical coil (solenoid coil) 254 wound around the bobbin 253 is disposed around the sleeve 244, and the bobbin 253 and the coil 254 are surrounded by an integrally molded resin member 255. The solenoid housing 240, the fixed core 242 and the movable core 248 are all formed of a magnetic material to constitute a magnetic circuit, while the sleeve 244 is formed of a nonmagnetic stainless steel material.

  Here, a radial hole 256 is formed at the root of the tip of the fixed core 242, and a communication hole 258 that connects the radial hole 256 and the pressure sensing chamber 214 is formed in the valve housing 202. Further, the inner diameter of the central portion and the other end portion of the fixed core 242 is larger than the outer diameters of the valve body 210 and the solenoid rod 250, and the central portion of the fixed core 242 is between the pressure sensing chamber 214 and the core housing space 246. And the inside of the other end part, it communicates via the radial hole 256 and the communication hole 258.

Accordingly, the pressure of the crank chamber 105 (crank pressure Pc) acts on one end surface of the valve body 210 as a force in the valve opening direction, while the pressure of the suction chamber 140 (suction pressure Ps) acts on the other end surface of the valve body 210. ) Acts as a force in the valve closing direction.
Note that by setting the area of the valve hole 204 equal to the cross-sectional area of the portion of the valve body 210 supported by the distal end portion of the fixed core 242, the opening and closing operation of the valve body 210 is performed in the valve chamber 208. The pressure, in other words, the pressure in the discharge chamber 142 (discharge pressure Pd) is not involved. In this case, the suction pressure control characteristic of the capacity control valve 200 is not affected by the discharge pressure Pd.

Further, by setting the area of the valve hole 204 equal to the step area of the portion of the pressure-sensitive rod 220 that slides with the axial hole 218, the pressure in the valve hole 204 is used for opening and closing the valve body 210. In other words, the pressure in the crank chamber 105 (crank pressure Pc) is not involved.
As a result, the suction pressure control characteristic of the capacity control valve 200 is substantially unaffected by the discharge pressure Pd and the crank pressure Pc. For this reason, as shown in FIG. 3, Formula (1) and Formula (2), based on the current (drive current I) supplied to the coil 254, the target value of the suction pressure Ps to be controlled (target suction pressure Pss). ) Is uniquely determined.

  In Formula (1), F (I) is an electromagnetic force acting on the movable core 248 by energizing the coil 254, and Sb is an effective area of the bellows 230. Further, fs1 is an urging force of the compression coil spring 252 and fs2 is an urging force of the compression coil spring 236 of the pressure sensor 228. F (I) = A · I (where A is a constant), and taking this relationship into account, transforming equation (1) yields equation (2).

When drive current I is supplied to coil 254 from the outside, electromagnetic force F (I) acts on movable core 248. The movable core 248 is attracted toward the fixed core 242 by the electromagnetic force F (I), and thereby the valve body 210 is urged in the valve closing direction.
In the refrigeration cycle 10 of the vehicle air conditioning system, when the air conditioner is not operated in the engine operating state, the drive current I is not supplied to the coil 254 of the capacity control valve 200. As a result, the valve body 210 is forcibly separated from the valve seat by the elastic force of the forcible release spring 226, the capacity control valve 200 is opened, and the discharge capacity of the compressor 100 is minimized.

  At this time, since the check valve 170 is always applied with a force in the closing direction, the flow of the refrigerant from the compressor 100 to the circulation path 12 is blocked. As a result, the refrigerant discharged into the discharge chamber 142 with the minimum discharge capacity circulates inside the compressor 100. That is, the refrigerant in the discharge chamber 142 flows into the crank chamber 105 through the air supply passage 160 and then returns to the suction chamber 140 through the extraction passage 162.

On the other hand, when the air conditioner is operated, the drive current I is supplied to the coil 254, and the valve body 210 is brought into contact with the valve seat against the elastic force of the compression coil spring 236 as shown in FIG. Touch. As a result, the capacity control valve 200 is closed and the supply passage 160 is shut off, so that the crank pressure Pc decreases and becomes equal to the suction pressure Ps.
Thereby, the inclination angle of the swash plate 107 is increased, and the stroke of the piston 130 is increased. As a result, when the pressure in the discharge chamber 142 increases and the differential pressure across the check valve 170 exceeds a predetermined value, the check valve 170 is opened and compressed refrigerant is supplied to the circulation path 12.

During the operation of the variable capacity compressor 100, the control system A of the variable capacity compressor 100 adjusts the drive current I supplied to the coil 254 of the capacity control valve 200 to adjust the variable capacity compressor 100. To control the discharge capacity.
FIG. 4 is a block diagram showing a schematic configuration of a control system A that controls the discharge capacity of the variable capacity compressor 100 via the capacity control valve 200.

The control system A includes a first control device 400A, a second control device 400B, and a third control device 400C, and at least the first control device 400A and the third control device 400C are separate bodies. Being separate means that the first control device 400A and the third control device 400C are physically or mechanically separate.
The first control device 400A, the second control device 400B, and the third control device 400C can be configured by ECUs (electronic control devices), respectively. The second control device 400B may be integrated with one of the first control device 400A and the third control device.

For example, one ECU may have the functions of the first control device 400A and the second control device 400B, and the other ECU may have the function of the third control device 400C. Alternatively, one ECU may have the function of the first control device 400A, and the other ECU may have the functions of the second control device 400B and the third control device 400C.
As described above, an ECU in which one ECU has two functions among the first to third control devices 400A, 400B, 400C is also referred to as a control unit in this specification. In the control system A, the first control device 400A and the second control device 400B constitute a control unit 400U1.

The first control device 400A is also referred to as an air conditioner ECU because it can be integrated with an air conditioner ECU that controls the entire air conditioning system. On the other hand, since the third control device 400C is exclusively used for controlling the compressor 100, it is also referred to as a compressor ECU.
400 A of 1st control apparatuses set the target value of the controlled variable of the control system A based on at least 1 external information. The second control device 400B calculates a standard manipulated variable based on the target value of the controlled variable. The third control device 400C corrects the standard operation amount based on the variation in the characteristics of at least one of the variable capacity compressor 100 and the capacity control valve 200, and the coil 254 based on the corrected operation amount. The drive current I supplied to is adjusted.

  One or more pieces of external information are input to the first control device 400A. For example, the first control device includes an air conditioner switch 401, an in-vehicle temperature target setting unit 402, an evaporator temperature sensor 403 that detects an evaporator outlet air temperature, an outside air temperature sensor 404, a solar radiation sensor 405, an in-vehicle temperature sensor 406, a high-pressure side. Signals from the pressure sensor 407 for detecting the refrigerant pressure, the evaporator fan voltage detection means 408, the inside / outside air door position detection means 409, the engine speed sensor 410, the accelerator opening sensor 411, and the like are input.

  The first control device 400A includes an evaporator target temperature setting means 420. When the air conditioner switch 401 is turned on, the evaporator target temperature setting means 420 is based on at least one external information including the in-vehicle temperature target value set by the in-vehicle temperature target setting means 402, and the evaporator 18 in the air circuit. The target value (evaporator target outlet air temperature Tes) of the air temperature at the outlet (evaporator outlet air temperature Te) is set. The evaporator outlet air temperature Te is a control target (control amount) of the control system A, and the evaporator temperature sensor 403 is means for detecting the control amount (control amount detection means).

  The second control device 400B includes a drive current calculation unit 421. The drive current calculation unit 421 is detected by the evaporator temperature sensor 403 to the evaporator target outlet air temperature Te set by the evaporator temperature target setting unit 420. The standard operation amount is calculated so that the evaporator outlet air temperature Te approaches. The operation amount is, for example, the current value of the drive current I supplied to the coil 254 of the capacity control valve 200. The calculated standard operation amount is output as a control command value from the second control device 400B and input to the current adjusting means 440 of the third control device 400C.

  The drive current calculation unit 421 may calculate a standard operation amount by either feedback control or feedforward control. In the case of feedback control, as described above, the operation amount can be calculated so that the difference ΔT between the evaporator target outlet air temperature Tes and the evaporator outlet air temperature Te is reduced. In the case of feed-forward control, a standard manipulated variable can be calculated based on a plurality of external information and a function having the evaporator target outlet air temperature Tes as variables.

  As shown in FIG. 5, the third control device 400 </ b> C has a control circuit that constitutes the current adjusting means 440. The current adjusting means 440 is integrally provided with a connection terminal 441, and the connection terminal 441 is used for physical and electrical connection between the second control device 400B, that is, the control unit 400U1 and the third control device 400C. Further, the current adjusting means 440 is integrally provided with a connection terminal 442, and the connection terminal 442 is used for electrical connection between the third control circuit 400C and the coil 254. The current adjusting means 440 is embedded in a package 443 made of resin, and the connection terminals 441 are embedded in the resin except for the tip side. The connection terminal 441 and the connection terminal 442 are detachably connected.

That is, the control unit U1 is electrically connected to the third control device 400C by the lead wire. Connection terminals are also provided at both ends of the lead wire, and the lead wire is detachably electrically connected to the control unit U1 and the third control device 400C via the connection terminal.
On the other hand, the connection terminal 442 is embedded in the resin after one end of the lead wire 444 is connected. The third control device 400C is configured integrally with the capacity control valve 200 via the lead wire 444.

  Since the third control device 400C is connected to the coil 254 and the lead wire 444, it can be arranged freely. For example, the third control is performed at a position that is not attached to the variable capacity compressor 100 and is not easily affected by vibration or heat while being connected to a connection terminal of a lead wire that connects between the control unit 400U1 and the third control device 400C. The device 400C may be held. In this way, the reliability of the third control device 400C is ensured.

  FIG. 6 shows the configuration of the current adjusting means 440 of the third control device 400C. The current adjusting means 440 includes a switching element 450, and the switching element 450 is inserted in series with the coil 254 of the capacity control valve 200 in a power supply line extending between the power supply 451 and the ground. The switching element 450 can electrically connect the power supply line, and the operation of the switching element 450 supplies the drive current I to the coil 254 by PWM (pulse width modulation method) with a predetermined drive frequency.

In order to form a flywheel circuit, a diode 452 is connected in parallel with the coil 254.
A predetermined pulse signal is input to the switching element 450 from the solenoid driving means 453. The carrier frequency of the pulse signal is 400 Hz, for example, and the duty ratio in PWM is changed by changing the pulse width of this pulse signal.

In addition, for example, an ammeter is inserted in the power supply line as the current detection unit 454, and the current detection unit 454 detects the drive current I flowing through the coil 254.
The current detection unit 454 inputs the detected drive current I to the solenoid drive unit 453. A drive current I as an operation amount corrected by the correction unit 455 is input to the solenoid drive unit 453, and the solenoid drive unit 453 receives the drive current I detected by the current detection unit 454 and the correction unit 455. The generated drive current I is compared. Based on the comparison result, the solenoid driving unit 453 changes the control signal generated by the solenoid driving unit 453 so that the detected driving current I approaches the inputted driving current I.

When the current adjustment unit 440 adjusts the drive current I with the duty ratio, the drive current calculation unit 421 may calculate the duty ratio as a parameter related to the drive current I. In this case, the operation amount calculated by the drive current calculation means 421 is the duty ratio of the pulse signal input to the switching element 450.
That is, the operation amount may be a current value of the drive current I or a physical amount such as a duty ratio related to the drive current I.

The correction unit 455 described above corrects the operation amount calculated by the drive current calculation unit 421 based on variation in characteristics of at least one of the variable capacity compressor 100 and the capacity control valve 200. Then, the correction unit 455 inputs the corrected operation amount to the solenoid driving unit 453.
More specifically, the relationship between the drive current I flowing through the coil 254 and the suction pressure Ps, that is, the suction pressure control characteristics varies as shown by the broken lines A1 and B1 in FIG. The broken line A1 indicates the upper limit of variation when the variable capacity compressor 100 and the capacity control valve 200 having the same specifications are used, and the broken line B1 is the lower limit of variation.

  The straight line denoted by reference numeral S1 in FIG. 3 indicates the suction pressure control characteristic (reference characteristic) that serves as a reference for the specification, and the second control device 400B calculates a standard operation amount based on this reference characteristic. Then, the correction unit 455 corrects the operation amount so that the actual suction pressure Ps approaches the target suction pressure Pss in other words, in other words, the control amount approaches the target value in consideration of variation in characteristics. .

For example, the relational expression representing the reference characteristic can be expressed as the following expression (3) in consideration of the expression (2). Further, a relational expression representing actual characteristics including variation can be expressed as the following expression (4) in consideration of the expression (2).
Pss = −a1 · Iset + b1 (3)
Pss = −a2 · Ic + b2 (4)
However, in Formula (3) and Formula (4), a1, b1, a2, and b2 are constants. Further, Iset is a reference value of the drive current I determined from the target suction pressure Pss based on the reference characteristic, and Ic is a correction value of the drive current I calculated in consideration of characteristic variation.

When correcting the manipulated variable, it is necessary to determine the drive current I in Expression (4) so that the right side of Expression (3) and the right side of Expression (4) are equal. This is expressed by the following equation (5).
Pss = −a1 · Iset + b1 = −a2 · Ic + b2 (5)
Therefore, the correction value Ic of the drive current I is obtained by the following equation.
Ic = (a1 / a2) .Iset + (b2-b1) / a2 (6)
Although the constants a1 and b1 in the equation (3) can be determined in advance according to the specifications, the constants a2 and b2 in the equation (4) are determined from actual individual characteristics of the capacity control valve 200.

Specifically, the constants a2 and b2 measure the actual suction pressures Ps1 and Ps2 when two drive currents Iset1 and Iset2 having different magnitudes are supplied to the coil 254 of the capacity control valve 200, respectively. These drive currents Iset1, Iset2 and suction pressures Ps1, Ps2 can be determined.
If the constants a2 and b2 as well as the constants a1 and b1 are input to the correction unit 455 as correction signals, the correction unit 455 calculates the correction value Ic from the reference value Iset of the drive current I according to the equation (6). It can be calculated.

  In the control system A of the variable capacity compressor 100 described above, the first control device 400A that sets the target value of the control amount and the third control device 400C that adjusts the drive current I are provided separately, and the third control device. 400C corrects the standard operation amount calculated by the second control device 400B based on variations in characteristics of at least one of the variable displacement compressor 100 and the displacement control valve 200. In this way, by providing the function for correcting the standard operation amount to the third control device 400C, the third control device 400C is optimized in accordance with the variation in characteristics.

This optimization is easy because the first control device 400A and the third control device 400C are separate bodies. And by optimizing the 3rd control apparatus 400C, according to this control system A, the discharge capacity | capacitance of the variable capacity compressor 100 is accurately controlled via the capacity | capacitance control valve 200. FIG.
In the control system A of the variable capacity compressor 100 described above, the discharge capacity of the variable capacity compressor 100 is accurately controlled with a simpler configuration by correcting the current value of the drive current I as the operation amount.

In the control system A of the variable capacity compressor 100 described above, the second control device 400B calculates a standard operation amount based on the target value of the control amount and external information. For this reason, the drive current I is accurately adjusted by the third control device 400C regardless of the type of control amount set by the first control device 400A.
In the control system A of the variable displacement compressor 100 described above, the operation amount is corrected based on the variation in the relationship between the operation amount based on the individual difference of the variable displacement compressor 100 or the displacement control valve 200 and the pressure of the working fluid. Variation in the relationship between the operation amount based on the individual difference of the variable displacement compressor 100 or the displacement control valve 200 and the pressure of the working fluid has a great influence on the accuracy of the control. According to this control system A, the control accuracy Is definitely higher. That is, according to the control system A, the control amount can be brought close to the target value with high accuracy.

  More specifically, in the prior art, since the control characteristics of the variable capacity compressor 100 and the capacity control valve 200 vary, the suction pressure Ps cannot be brought close to the target suction pressure Pss on the lower limit side or the upper limit side of the drive current I. There was a problem that the substantial control range narrowed. On the other hand, in the capacity control system A, the operation amount is corrected based on the drive current I actually flowing through the coil 254 and the suction pressure Ps, so that the substantial control range is not narrowed. For this reason, the suction pressure Ps is brought close to the target suction pressure Pss over the entire range of the suction pressure control range set according to the specification.

The present invention is not limited to the first embodiment described above, and various modifications are possible.
FIG. 7 shows a schematic configuration of a control system B of the variable capacity compressor according to the second embodiment. In the control system B, the first control device 400A and the second control device 400B are separate bodies, and the second control device 400B and the third control device 400C are integrated to form a control unit 400U2. That is, the control unit 400U2 includes drive current calculation means 421 and current adjustment means 440. In this case, the drive current calculation unit 421 and the current adjustment unit 440 can be formed on the same substrate.

Similar to the correction unit 455 of the control system A, the correction unit 460 of the control system B corrects a standard operation amount.
However, the control unit 400U2 has an input unit to which the current values of the correction drive currents Iset1 and Iset2 are input so that the correction drive currents Iset1 and Iset2 can be input to the correction unit 460 from the outside. 470.

  The correcting unit 460 outputs the input current value to the solenoid driving unit 453, whereby the correction driving currents Iset 1 and Iset 2 are sequentially supplied to the coil 254. A correction amount is determined from the drive currents Iset1 and Iset2 supplied for correction and the suction pressure Ps at that time, and a correction signal related to the correction amount is input to the correction means 460. The correction amount is stored in the storage unit 462 of the correction unit 460, and the correction unit 460 corrects the operation amount with reference to the stored correction amount.

In the control system B of the variable capacity compressor 100 described above, a signal related to the operation amount for correction for determining the correction amount can be input to the control unit 400U2 in addition to the standard operation amount. Is easy.
In addition to being able to select and set an appropriate control amount from various physical quantities for the first control device 400A, the second control device 400B and the third control device 400C are integrated. Thus, the versatility or commonality of the first control device 400A is increased.

  More specifically, in the second embodiment, the control amount is not limited to the evaporator outlet air temperature Te, and the control amount may be the torque value of the compressor 100 or the refrigerant circulation amount of the refrigeration cycle 10. In this case, a target value of the torque value or refrigerant circulation amount of the variable capacity compressor 100 is set by the target value setting means, and the drive current I is adjusted so that the torque value or refrigerant circulation amount approaches the target value. When the control amount is the evaporator outlet air temperature Te, the control performed by the control system is referred to as air conditioning control, and when it is a torque value, it is referred to as torque control.

  The control amount may be the refrigerant pressure or refrigerant temperature on the high-pressure side of the refrigeration cycle 10 or the compressor 100 temperature. In this case, the drive current I is adjusted so that the refrigerant pressure, refrigerant temperature, or compressor 100 temperature on the high-pressure side of the refrigeration cycle 10 approaches its target value. When the control amount is the refrigerant pressure or refrigerant temperature on the high-pressure side of the refrigeration cycle 10 or the temperature of the compressor 100, the control performed by the control system is referred to as protection control.

Regardless of the type of control amount, the standard operation amount is calculated based on the target value, the standard operation amount is corrected, and the drive current is adjusted based on the corrected operation amount.
Further, in the control system B of the variable capacity compressor 100 described above, the current value of the correction drive current can be input to the third control device 400C via the first control device 400A. For this reason, even after the control system B is assembled in a vehicle, for example, it is easy to input a signal related to variation in characteristics, that is, a signal (correction signal) for correcting the operation amount, to the third control device 400C. Furthermore, it is easy to determine the failure of the variable capacity compressor 100 by measuring a change in the control amount or the drive current I while changing the correction signal.

In the control system A of the variable displacement compressor 100 described above, the third control device 400C is fixed to the variable displacement compressor 100 or the displacement control valve 200. If this fixing work is performed in the factory, the optimization work of the third control device 400C can be easily performed in the factory, and a large number of the third control devices 400C can be optimized in a short time.
In the second embodiment, an operation amount monitoring unit that monitors a standard operation amount calculated by the drive current calculation unit 421 may be provided. If the standard operation amount calculated by the operation amount monitoring means is monitored, the correction can be made without inputting the current value of the driving current I for correction from the outside.

  In the first embodiment and the second embodiment, an operation for determining the correction amount may be performed via the first control device 400A. That is, the correction amount determining means 472 may be provided in the first control device 400A as in the control system of the third embodiment shown in FIG. The correction amount determining means 472 of the first control device 400A is operated from the outside using the control panel 474. The correction amount determination unit 472 determines a correction amount in response to an instruction from the control panel 474 and inputs the determined correction amount to the correction unit 460. In this case, the determination of the correction amount and the failure determination of the variable capacity compressor 100 can be easily executed even after the control system is mounted on the vehicle.

  In the first embodiment and the second embodiment, the third control device 400C or the control unit 400U2 and the coil 254 of the capacity control valve 200 are separately molded with resin, but the third control device 400C or the control unit 400U2 and the capacity control are performed. The coil 254 of the valve 200 may be integrally molded with resin. However, it is only necessary that the first control device 400A and the third control device 400C are separated, and the third control device 400C may not be integrated with the displacement control valve 200.

  In the first embodiment and the second embodiment, for example, as shown in FIG. 9, external connection terminals can be attached to and detached from the connection terminals 441 and 442 at both ends of the third control device 400C or the control unit U2. It may be possible to connect. In this case, the third control device 400C or the control unit U2 may be arranged at an intermediate position between the first control device 400A and the variable capacity compressor 100.

  In the first embodiment and the second embodiment, instead of the capacity control valve 200 for controlling the suction pressure Ps, for example, the capacity control valve 300 shown in FIG. 10 may be replaced. When the capacity control valve 300 is used, by adjusting the driving current I supplied to the coil 316, as shown in FIG. 11, the differential pressure between the suction pressure Ps and the pressure in the discharge chamber 142 (discharge pressure Pd). (Pd-Ps differential pressure) is controlled. In FIG. 11, a straight line with a reference sign S2 represents a standard characteristic, and broken lines A2 and B2 indicate an upper limit and a lower limit of the variation range, respectively.

Furthermore, a displacement control valve that controls the differential pressure between two points in the discharge pressure region of the refrigeration cycle 10 or the differential pressure between two points in the suction pressure region may be replaced.
In addition, instead of a capacity control valve that controls opening and closing of the air supply passage 162 that communicates between the discharge chamber 142 and the crank chamber 105, a capacity control valve that controls opening and closing of the extraction passage 162 that communicates between the suction chamber 140 and the crank chamber 105 is used. May be.

  Although the variable capacity compressor 100 of the first embodiment and the second embodiment is a clutchless compressor, a compressor with an electromagnetic clutch equipped with an electromagnetic clutch may be used instead of a pulley. The compression mechanism is not limited to the swash plate type, and may be a swing plate type, a vane type, or a scroll type. Further, an electric type variable capacity compressor driven by an electric motor may be used.

  Finally, the control system for the variable capacity compressor according to 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 the vehicle air conditioning system to which the control system of 1st Embodiment is applied with the longitudinal cross-section of a variable capacity compressor. It is a figure for demonstrating schematic structure of the capacity | capacitance control valve used for the refrigerating cycle of FIG. 1 with the connection state of the capacity | capacitance control valve in a compressor. 2 is a graph showing a relationship between a drive current of a capacity control valve and a target suction pressure in the refrigeration cycle of FIG. 1. It is a block diagram which shows schematic structure of the control system of 1st Embodiment. It is a figure which shows schematic structure of the 3rd control apparatus in the control system of FIG. It is a block diagram which shows schematic structure of the electric current adjustment means of the 3rd control apparatus in FIG. It is a block diagram which shows schematic structure of the control system of 2nd Embodiment. It is a block diagram which shows schematic structure of the control system of 3rd Embodiment. It is a figure which shows the modification of the 3rd control apparatus of FIG. It is a figure for demonstrating schematic structure of the capacity | capacitance control valve of a modification with the connection state of the capacity | capacitance control valve in a compressor. It is a graph which shows the relationship between a drive current at the time of using the capacity | capacitance control valve of FIG. 10, and Pd-Ps differential pressure | voltage.

Explanation of symbols

A control system 100 variable capacity compressor 200 capacity control valve 254 coil 400A first control device 400B second control device 400C third control device

Claims (7)

In a variable capacity compressor control system applied to discharge capacity control of a variable capacity compressor through an electromagnetic control valve having a valve body to which a pressure of a working fluid and a load from a solenoid unit are applied,
A first control device that sets a target value of a control amount based on at least one external information;
A second control device that calculates a standard operation amount based on a target value of the control amount;
A third control device provided separately from the first control device, wherein the standard operation amount is corrected based on variation in characteristics of at least one of the variable capacity compressor and the capacity control valve. And a third control device for adjusting a drive current supplied to the coil of the solenoid unit based on the corrected operation amount.   The control system for a variable capacity compressor according to claim 1, wherein the operation amount is a current value of the drive current. The second control device calculates the standard operation amount based on a target value of the control amount and at least one external information,
The control system for a variable capacity compressor according to claim 1 or 2, wherein the second control device and the third control device are integrally provided to constitute one control unit.   The control unit includes an input unit for inputting a signal related to an operation amount for correction from the outside to the third control device when determining a correction amount for correcting the variation in characteristics. The control system of the variable capacity compressor according to claim 3.   5. The characteristic variation is a variation in a relationship between the operation amount and the pressure of the working fluid based on individual differences of the variable capacity compressor or the capacity control valve. A control system for a variable capacity compressor according to claim 1. The first control device has correction amount determination means,
The correction amount determining means includes a correction amount determining means for determining a correction amount for correcting the variation in the characteristics by an external operation and inputting the determined correction amount to the third control device. The control system for a variable capacity compressor according to any one of claims 1 to 5.   The control system for a variable capacity compressor according to any one of claims 1 to 6, wherein the third control device is fixed to one of the variable capacity compressor and a capacity control valve.

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