JP2000205667A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem of shortage of heating capacity which occurs as a working fluid is released to a cooling circuit and another problem of worsened energy efficiency which does as the working fluid is released outside a heating circuit in an air conditioner with a hot gas bypass heater circuit. SOLUTION: There are arranged a compressor 101, a cooling circuit, a heating circuit and capacity altering means 301 and 401. The compressor 101 has an intake part 115, a delivery part 120 and a drive means 130. A first capacity altering means 301 lets the delivery part 120 communicate with a drive chamber 110 when an intake pressure Ps of a working fluid reaches a specified low pressure state, and a second capacity altering means 401 lets the delivery part 120 communicate with the drive chamber 110 when the delivery pressure Pd of the working fluid reaches a specified high pressure state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a cooling circuit and a heating circuit which operate by using a working fluid compressed by a compressor, and more particularly, to a method for reliably and rapidly detecting an abnormally high discharge pressure of a working fluid. The present invention relates to an air conditioner for suppressing air pollution.

[0002]

2. Description of the Related Art An example of this type of air conditioner is disclosed in Japanese Unexamined Patent Publication No.
No. 9630. As shown in FIG. 1, this air conditioner includes a compressor 1, a cooling circuit 51, a heating circuit 52, and a control device 83. The cooling circuit 51
The compressor 1 includes a condenser 55 provided on a path from a discharge part D to a suction part S of the compressor 1, a first expansion valve 57, and a heat exchanger 59. -The high-pressure working fluid is supplied to the compressor 1 via the above devices.
And this cycle is repeated. Heating circuit 52
Is composed of a bypass passage 52a from the discharge part D of the compressor 1 to the heat exchanger 59, a second expansion valve 63 provided on the bypass passage 52a, and the heat exchanger 59, The high-temperature and high-pressure working fluid discharged from the machine 1 is sucked into the compressor 1 via the second expansion valve 63 and the heat exchanger 59 without being sent to the condenser 55, and this cycle is repeated. The heating circuit 52 is generally called a hot gas bypass heater. Switching between the cooling circuit 51 and the heating circuit 52 is performed by switching valves 53a and 53.
The opening / closing operation is performed by the controller 83.

In this type of air conditioner, when the heating circuit 52 is operated, the discharge pressure of the working fluid is higher than when the cooling circuit 51 is selected. Therefore, during the operation of the heating circuit 52, the discharge pressure tends to be abnormally high due to, for example, a temporary increase in the rotation speed of the compressor 1. Therefore, in the related art, a working fluid discharge passage 91 further provided with a pressure relief valve 93 is provided. The working fluid discharge passage 91 includes a heating circuit 52 and a cooling circuit 5.
The pressure relief valve 93 is opened to discharge the working fluid to the cooling circuit 51 side when the discharge pressure of the working fluid becomes abnormally high during the operation of the heating circuit 52. This prior art includes a cooling circuit 51 and a heating circuit 5.
Paying attention to the fact that 2 is selectively selected by the switching valves 53a and 53b, when the discharge pressure becomes abnormally high during the operation of the heating circuit 52, the working fluid is discharged to the unused cooling circuit 51 side. By doing so, abnormal high pressure is not applied to the heating circuit 52.

[0004]

This conventional technique for preventing abnormal high pressure is a system in which a working fluid is discharged from an operating heating circuit 52 to an unused cooling circuit 51, and the discharge pressure during the operation of the heating circuit 52 is controlled. Can be suppressed, but the working fluid in the heating circuit 52 is discharged to the cooling circuit 51 every time the discharge pressure increases, and the heating circuit 52
It is likely that the working fluid in the interior decreases and the heating capacity becomes insufficient. Further, the conventional technology for countermeasures against abnormal high pressure causes the compressor 1 to work and discharges the working fluid that has been pressurized to a high pressure to the outside of the circuit, so that the energy efficiency is low.

Therefore, in the present invention, there is a problem of a technique for countermeasures for abnormally high discharge pressure in an air conditioner provided with a heating circuit configured as a hot gas bypass heater circuit, that is, the working fluid in the hot gas bypass heater circuit is cooled. To solve the problem that the heating capacity is insufficient due to being discharged to the compressor, and the energy efficiency is poor because the working fluid that is caused to work by the compressor is wastedly discharged to the outside of the heating circuit. Make it an issue.

[0006]

Means for solving the above problems are described in the inventions described in the respective claims.

In the air conditioner of the first aspect, a variable displacement compressor is used as a drive source for operating the cooling circuit and the heating circuit. Further, a so-called hot gas bypass heater is used in a heating circuit in the present air conditioner. In the hot gas bypass heater, it is preferable to provide a decompression device such as an expansion valve in a bypass from the discharge section to the heat exchanger.

In this variable displacement compressor, a drive means capable of reducing the discharge capacity by increasing the pressure in the drive chamber is used. When the discharge capacity decreases, the discharge pressure of the working fluid decreases and the suction pressure increases. Conversely, when the discharge capacity increases, the discharge pressure of the working fluid increases and the suction pressure decreases. The present air conditioner is configured to increase the pressure in the drive room by discharging a high-pressure working fluid from the discharge section to the drive room.

[0009] The reduction of the suction pressure tends to be a problem especially when the cooling circuit is operated. This is because if the suction pressure is too low, frost may form on the heat exchanger in the cooling circuit. on the other hand,
During operation of the heating circuit, frost formation in the heat exchanger is not a problem, so that it is less necessary to take measures for abnormally low suction pressure. On the other hand, an increase in the discharge pressure tends to be a problem particularly during the operation of the heating circuit. In the heating circuit, the operating pressure is set high to ensure the heating capacity, so the range between the normal operating pressure and the upper limit pressure of the circuit is narrow, and even if the discharge pressure slightly increases from the set pressure, the upper limit pressure is reached. In addition, since the hot gas bypass heater has a configuration in which a bypass circuit is provided in the cooling circuit to form a heating circuit, the circuit capacity is small, and the degree of increase in the discharge pressure is likely to be sharp,
For this reason, it is necessary to strictly take measures against abnormally high discharge pressure. On the other hand, when the cooling circuit is activated, a lower operating pressure is used than when the heating circuit is activated. Big,
There is little need to take strict measures against abnormally high discharge pressure such as a hot gas bypass heater.

In the present air conditioner, the first capacity changing means and the second capacity changing means make the discharge section and the drive chamber communicate with each other. When the suction pressure of the working fluid becomes a predetermined low pressure state, the first displacement changing means communicates the discharge section with the drive chamber. As a result, the working fluid is discharged from the discharge section on the high pressure side to the drive chamber on the low pressure side, so that the pressure in the drive chamber increases, the discharge capacity decreases, and the suction pressure of the working fluid increases.
On the other hand, when the discharge pressure of the working fluid has reached a predetermined high pressure state, the second displacement changing means communicates the discharge part with the drive chamber. As a result, the working fluid is discharged from the high-pressure side discharge section to the low-pressure side drive chamber, so that the pressure in the drive chamber increases, the discharge capacity decreases, and the discharge pressure of the working fluid decreases. Here, the first capacity changing means is configured to include a valve for eliminating an abnormally low suction pressure state during the operation of the cooling circuit, that is, a low pressure control valve (suction pressure control valve) for the cooling circuit, and the second capacity changing means has a second configuration. It is preferable that the capacity changing means has a configuration that includes a valve for eliminating an abnormally high discharge pressure state when the heating circuit is operated, that is, a high-pressure control valve (discharge pressure control valve) for the heating circuit. In this case, if the suction pressure becomes abnormally low during the cooling circuit operation, the low-pressure control valve is opened to discharge the working fluid from the discharge section to the drive chamber, which causes a problem such as frost formation in the heat exchanger provided in the cooling circuit. It will be effectively resolved. If the discharge pressure becomes abnormally high when the heating circuit is activated, the high-pressure control valve is opened to release the working fluid from the discharge section to the drive chamber, and the abnormally high discharge pressure of the working fluid during the heating circuit is effective. Will be resolved. The passage in which the first capacity changing unit is arranged and the passage in which the second capacity changing unit is arranged may be separately provided in parallel with each other, or may be provided on the same route while using one route. The first and second capacity changing means may be arranged in parallel.

According to the air conditioner of the second aspect, the first working fluid discharge means is disposed in the passage connecting the discharge portion and the drive chamber, and the suction pressure of the working fluid is set to a predetermined value when the cooling circuit is operated. It has a first valve that opens when low pressure occurs. The second displacement changing means is disposed in a passage connecting the discharge section and the drive chamber, and is opened when the discharge pressure of the working fluid becomes a predetermined high pressure state during operation of the heating circuit. Having. When the suction pressure becomes abnormally low during the operation of the cooling circuit, the first valve is opened, so that the discharge unit and the drive chamber are connected. As a result, the working fluid is discharged from the high-pressure side discharge section to the low-pressure side drive chamber via the first capacity changing means. As a result, the discharge capacity is reduced and the suction pressure of the working fluid is increased. The abnormally low suction pressure state at the time is eliminated. Further, when the discharge pressure is in an abnormally high pressure state when the heating circuit is activated, the discharge portion and the drive chamber are communicated by opening the second valve. As a result, the working fluid is discharged from the high-pressure side discharge section to the low-pressure side drive chamber via the second capacity changing means. Will be resolved.

[0012] In the air conditioner according to the third aspect, in the air conditioner according to the second aspect, the first and second valves are disposed in the housing of the compressor, so that the structure of the entire apparatus can be simplified. .

According to a fourth aspect of the present invention, in the air conditioner of the second or third aspect, the reference valve opening pressure of the first and second valves can be changed. That is, by appropriately setting the valve opening reference pressure of each valve with respect to the discharge pressure or the suction pressure of the working fluid, the first pressure during the operation of the cooling / heating circuit
And the opening and closing of the second valve can be controlled in relation to the pressure of the working fluid.

According to a fifth aspect of the present invention, in the air conditioner of the fourth aspect, the first valve opens when the suction pressure falls below the valve opening reference pressure, and the second valve opens when the discharge pressure exceeds the valve opening reference pressure. It is configured to open. The reference valve opening pressure of the first valve during the operation of the cooling circuit is the lower limit reference value of the suction pressure during the operation of the cooling circuit. That is, when the suction pressure of the working fluid is higher than the lower limit reference value, the first valve does not satisfy the valve opening condition and is not opened. Conversely, if the suction pressure becomes lower than the lower limit reference value, it means that an abnormally low suction pressure state has occurred. In this case, the first valve satisfies the valve opening reference pressure and Will be opened. As a result, the working fluid is discharged from the discharge section on the high pressure side to the drive chamber on the low pressure side via the first valve, and the discharge capacity is reduced and the suction pressure is increased, whereby an abnormally low pressure state of the working fluid is avoided. Will be. Further, the valve opening reference pressure of the second valve during the operation of the cooling circuit is set higher than the upper limit reference value of the discharge pressure during the operation of the cooling circuit. That is, the discharge pressure does not always satisfy the valve opening reference pressure of the second valve during the operation of the cooling circuit, and the second valve is always closed during the operation of the cooling circuit. Therefore, the capacity control during the operation of the cooling circuit is performed only through the first valve.

The reference valve opening pressure of the first valve during the operation of the heating circuit is set lower than the lower limit reference value of the suction pressure of the working fluid during the operation of the heating circuit. Therefore, the first valve is always closed during the operation of the heating circuit. In addition, the valve opening reference pressure of the second valve is set to the upper limit reference value of the discharge pressure when the heating circuit is operating. If the discharge pressure during the operation of the heating circuit changes below the upper limit reference value, the second reference value is set. Will be closed. On the other hand, when the discharge pressure of the working fluid becomes a predetermined high pressure state (abnormal high pressure state exceeding the upper limit reference value) during the operation of the heating circuit, the second valve is opened. As a result, the working fluid is discharged from the discharge section to the drive chamber via the second volume changing means, and countermeasures against abnormally high discharge pressure are taken.

In the air conditioner according to the sixth aspect, the valve opening reference pressure of the first and second valves in the air conditioner according to the fourth or fifth aspect is such that a solenoid provided for each valve is energized or de-energized. This will be changed as appropriate.

According to a seventh aspect of the present invention, in the air conditioner of the second or third aspect, the first and / or second air conditioner is provided.
The capacity changing valve in the capacity changing means of (1) is configured to be opened by a differential pressure between a suction pressure of the working fluid and a pressure other than the suction pressure, or by a differential pressure between a discharge pressure of the working fluid and a pressure other than the discharge pressure. Have been. That is, both or one of the capacity changing valve in the capacity changing means for taking measures against abnormal low pressure of the suction pressure and the capacity changing valve in the capacity changing means for taking measures against abnormal high pressure of the discharge pressure is configured as a differential pressure valve. Further, a pilot valve is provided upstream of the capacity change valve configured as the differential pressure valve in a path (a working fluid discharge path) from the discharge section to the drive chamber. Through the opening and closing of the pilot valve, the pilot valve appropriately controls whether or not the working fluid is sent to the capacity change valve located on the downstream side.

In the air conditioner according to the eighth aspect, the air conditioner according to the seventh aspect is further devised with respect to opening / closing control by a pilot valve. The present pilot valve is open when displacement control is being performed by the displacement changing means, that is, when displacement control is being performed through opening and closing of a displacement change valve located downstream of the pilot valve. This is to allow the working fluid to be sent to the capacity change valve that is in charge of capacity control downstream of the pilot valve. On the other hand, when the capacity control is being performed by the other capacity changing means, that is, the capacity changing means on the side to which the pilot valve does not belong, the pilot valve is closed. When the capacity change valve is configured as a differential pressure valve, there is a possibility that the differential pressure valve may be opened carelessly depending on the relation of the differential pressure. Therefore, it is possible to prevent a problem that hinders the capacity control by the other capacity change means. Therefore, it is a measure to prevent the working fluid from being sent to the capacity change valve on the side where the capacity control is not performed.

In the air conditioner according to the ninth aspect, the pilot valve in the air conditioner according to the eighth aspect is configured to be opened and closed through energization or non-excitation of a solenoid, thereby realizing the opening and closing timing of the pilot valve and a reliable opening and closing operation. can do.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an air conditioner according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 2, the present air conditioner 100 is generally configured by a cooling circuit 151, a heating circuit 152, and a variable displacement compressor 101 which is a driving source of both circuits. Note that the capacity changing means, which is one of the components of the present invention, is not shown in FIG. 2 showing the general configuration of the air conditioner 100. The structure and operation of the capacity changing means will be described later in detail.

In this embodiment, the air conditioner 100 is configured as an on-vehicle air conditioner, and a drive shaft 125 of the variable displacement compressor 101 is connected to and driven by an engine 170 of a car.

The cooling circuit 151 includes the variable displacement compressor 10
The first expansion valve 157 and the condenser 155 disposed on the path 151a from the discharge part D to the suction part S of the variable displacement compressor 101 operate by using the high-pressure working fluid compressed in Step 1. It has a heat exchanger 159 and an accumulator 161. Heat exchanger 159 is commonly referred to as an evaporator.

The heating circuit 152 includes the variable displacement compressor 10
It operates using the high-temperature and high-pressure working fluid compressed in step 1,
Second expansion valve 16 arranged on bypass passage 152a for guiding the working fluid discharged from discharge section D to heat exchanger 159
3, the heat exchanger 159, and the accumulator 161. That is, the heating circuit 152 is connected to the cooling circuit 151.
Is used as a part of the components. The heating circuit 152 having such a structure is commonly called a hot gas bypass heater.

The heat exchanger 159 is juxtaposed with the hot water heater 171. Cooling hot water from the engine 170 is circulated in the hot water heater 171 via a pipe 173.
In FIG. 2, a first on-off valve 153a and a second on-off valve 153b
Is a switching valve for selectively operating either the cooling circuit 151 or the heating circuit 152.

When the cooling circuit 151 operates, the working fluid which has been compressed by the variable capacity compressor 101 and has become high temperature and high pressure is sent to the condenser 155, where the heat of the high temperature working fluid is discarded to the outside. Liquefy. Next, the working fluid is decompressed by the first expansion valve 157 and
It is sent to 59, where it takes external heat and gasifies. The gasified working fluid is returned to the variable displacement compressor 101 via the accumulator 161 and is recirculated.

When the heating circuit 152 is operating, the working fluid that has been compressed by the variable capacity compressor 101 and has become high temperature and high pressure is decompressed by the second expansion valve 163 and is subjected to heat exchange.
59, where the heat is released to the outside. Heating circuit 1
During the cycle of 52, the working fluid always circulates in a gaseous state through the heating circuit 152.

In the present embodiment, the heating circuit 152 is positioned as an auxiliary heating device. That is, the heat generated by the heat exchanger 159 during the operation of the heating circuit 152 is used as an auxiliary heating heat source for the hot water heater 171 described above. The heating circuit 152 is used, for example, at the time of starting the engine 170 or in a low-temperature environment such as when the outside air temperature is -20 ° C., for example, when the cooling water of the engine 170 does not have enough heat for heating.

Next, referring to FIG.
The structure of No. 1 will be described. A drive chamber 110 is formed inside the variable displacement compressor 101, and the drive chamber 1
The swash plate 130 is supported by the drive shaft 125 in the inside 10.
The swash plate 130 is supported by the drive shaft 125,
And rotates with the rotation of the drive shaft 125 in a state of being inclined with respect to. Further, the inclination angle of the swash plate 130 with respect to the drive shaft 125 is variable. Hereinafter, approaching a state orthogonal to the drive shaft 125 is referred to as “stand up of the swash plate 130”, and approaching horizontal in the illustrated state. "The swash plate 130 sleeps."

The swash plate 130 is connected at its peripheral edge to the head of the piston 135 via a movable shoe 131. A total of six pistons 135 are arranged around the drive shaft 125 (only one piston is shown in the figure), and are inserted into the six cylinder bores 109 so as to be slidable in the left-right direction in the figure. 6 cylinder bores 1
09 is fixed by a housing 101a of the variable displacement compressor 101 in the circumferential direction.

As shown, when the swash plate 130 tilts and rotates together with the drive shaft 125, the peripheral edge of the swash plate 130 slides relative to the fixed piston 135 in the circumferential direction. When the peripheral edge of the swash plate 130 inclined to the piston side is located corresponding to the piston 135 (FIG. 1 shows this state), the piston 135 is inserted deepest into the cylinder bore 109. When the peripheral edge of the swash plate 130 that is inclined most to the opposite side of the piston (the peripheral edge shown in the lower part of FIG. 3) is located corresponding to the piston 135 (the drive shaft 125 is rotated 180 degrees from the state of FIG. 3). (Corresponding to the case of rotation), the piston 135 is drawn out most from the cylinder bore 109. When the drive shaft 125 makes one rotation, each piston 135 makes one reciprocation in the left-right direction in each cylinder bore 109.

A suction hole 1 is provided at the bottom of each cylinder bore 109.
18a and a discharge hole 123a are provided, and the suction valve 118 corresponds to the suction hole 118a, and the discharge valve 123 corresponds to the discharge hole 123a. Each suction hole 118
a communicates with the suction chamber 115, and each discharge hole 123 a communicates with the discharge chamber 120. Piston 1 by swash plate 130
When 35 moves to the left in the figure, the working fluid is
16 to suction chamber 115, suction hole 118a, suction valve 118
Through the cylinder bore 109. Then
When the piston 135 moves rightward in the figure by the swash plate 130, the sucked working fluid is compressed to a high pressure state, and the discharge hole 123a, the discharge valve 123, the discharge chamber 120
Is discharged from the discharge port 121 via the

The displacement of the variable displacement compressor 101 is determined by the stroke of the piston 135. The stroke amount of the piston 135 is determined by the inclination angle of the swash plate 130. The more the swash plate 130 lies, the greater the stroke amount of the piston 135, and the larger the displacement of the variable displacement compressor 101. Conversely, the swash plate 130
, The stroke amount of the piston 135 becomes smaller, and the displacement of the variable displacement compressor 101 becomes smaller.

The inclination angle of the swash plate 130 is
, That is, the difference between the pressure in the drive chamber 110 and the pressure in the cylinder bore 109. In the present embodiment, the differential pressure is adjusted by increasing or decreasing the pressure in the drive chamber 110. When reducing the discharge capacity, the high-pressure working fluid in the discharge chamber 120 is supplied to the drive chamber 1
10 to increase the pressure in the drive chamber 110. Then, the swash plate 130 rises, the stroke amount of the piston 135 decreases, and the discharge capacity decreases. Conversely, when the capacity is to be increased, the working fluid in the discharge chamber 120 is prevented from being discharged to the drive chamber 110. Then, the swash plate 130 lies down, the stroke amount of the piston 135 increases, and the discharge capacity increases.

In the present embodiment, as shown in FIG. 3, two capacity changing means are provided for discharging the high-pressure working fluid from the discharge chamber 120 to the drive chamber 110. One is a cooling capacity changing means 301 and the other is a heating capacity changing means 401. The cooling capacity changing unit 301 includes:
Generally, the cooling capacity change valve 303 and the discharge chamber 12
0, a first cooling capacity change passage 321 connecting the cooling capacity change valve 303, and a second cooling capacity change path 322 connecting the cooling capacity change valve 303 and the drive chamber 110.
It is composed of The heating capacity changing unit 401 includes:
Generally, the heating capacity change valve 403 and the discharge chamber 12
0 and a first heating capacity change passage 421 connecting the heating capacity change valve 403 and a second heating capacity change path 422 connecting the heating capacity change valve 403 and the drive room 110.
It is composed of Further, the drive chamber 110 and the suction chamber 1
15 and is communicated by the decompression passage 501,
Although not shown, a throttle is provided on the pressure reducing passage 501.

The first and second cooling capacity change passages 32
Numerals 1 and 322 are connected to a cooling capacity change valve 303, and both are brought into a state of communication or non-communication by a valve body 305. The valve body 305 is connected to a bellows 315 that controls opening and closing of the valve body 305 based on a suction pressure Ps detected through a suction pressure detection passage 313, and is connected to a plunger 307 of a solenoid 309 through a connection member 311. Are linked. The solenoid 309 is
Energized or de-energized by energizing the plunger 30
7 is energized. That is, the valve body 305
When s becomes equal to or less than a predetermined pressure, the valve is opened by the bellows 315, and the valve opening reference pressure is controlled by the solenoid 309
Can be changed by appropriately adjusting the biasing force on the plunger 307. Alternatively, by increasing the power supply to the solenoid 309, the suction pressure P
A high biasing force is applied to the plunger 307 such that the valve body 305 is always closed regardless of the size of s.

The first heating capacity change passage 421 is provided with a first compartment 405 formed in the heating capacity change valve 403.
Connected to. Therefore, the pressure in the first compartment 405 is the discharge pressure Pd of the working fluid. The second heating capacity change passage 422 is connected to a second compartment 407 formed in the heating capacity change valve 403. Therefore, the second compartment 4
The pressure in 07 is the pressure Pc in the drive chamber 110. The first and second compartments 405 and 407 are brought into a state of communication or non-communication by the valve body 409. The valve body 409 is closed by a spring 409a in the valve closing direction (FIG. 3).
In the right direction), and the pressure (discharge pressure) Pd in the first compartment 405 is increased in the second compartment 40.
When the pressure becomes a predetermined value as compared with the pressure Pc in the driving chamber 7 (pressure in the driving chamber), the combined force of the pressure Pc in the second compartment 407 and the urging force of the spring 409a is overcome. (In FIG. 3, the valve element 409 moves to the left). Further, the valve body 409 is connected to the connecting member 411.
Through a plunger 413 of the solenoid 415. The solenoid 415 applies an urging force to the plunger 413 by excitation or non-excitation by energization. That is, the valve element 409 is opened when the discharge pressure Pd reaches a predetermined valve opening reference pressure, and the valve opening reference pressure can be changed by appropriately adjusting the urging force of the solenoid 415 to the plunger 413. Have been. Alternatively, by cutting off the power supply to the solenoid 415, a high urging force is applied to the plunger 413 by the spring 409a so that the valve body 409 is always closed regardless of the magnitude of the discharge pressure Pd.

Next, the operation of the present air conditioner will be described.
As described above, when the cooling circuit 151 shown in FIG. 2 is operated, the working fluid that has been compressed by the variable capacity compressor 101 and has become high temperature and high pressure is supplied to the condenser 155 and the first expansion valve 1.
The refrigerant is returned to the variable capacity compressor 101 via the heat exchanger 57, the heat exchanger 159 and the accumulator 161, and is recirculated. When the heating circuit 152 is operating, the variable displacement compressor 10
The working fluid compressed to a high pressure in step 1
The refrigerant is returned to the variable displacement compressor 101 via the second expansion valve 163, the heat exchanger 159, and the accumulator 161 on the 52a and recirculated.

Regarding the control of the discharge capacity, first, the cooling circuit 15
1 (see FIG. 2) will be described. Cooling circuit 15
At the time of one operation, the capacity control is performed using the cooling capacity changing means 301 described above, and the heating capacity changing means 401 is not used. Therefore, the energization of the solenoid 309 is appropriately adjusted for the cooling capacity change valve 303, and the suction pressure P of the working fluid is adjusted.
The valve opening reference pressure is set so that the valve element 305 opens when s reaches a predetermined reference value. The reference value relating to the suction pressure Ps is set to the lower limit value of the suction pressure at which frost does not occur in the heat exchanger 159 (see FIG. 2). That is, the suction pressure P
When s falls below the allowable lower limit, it is determined that the suction pressure Ps has entered an abnormally low pressure state, and the capacity control by the cooling capacity changing means 301 is started. On the other hand, the heating capacity change valve 403 is always closed during the operation of the cooling circuit so that the working fluid is not released from the discharge chamber 120 to the drive chamber 110 via the heating capacity change means 401. Specifically, the energization of the solenoid 415 is appropriately adjusted, and the valve opening reference pressure of the heating capacity change valve 403 is set to be higher than the upper limit value of the discharge pressure Pd of the working fluid during the operation of the cooling circuit. As a result, the valve opening reference pressure of the heating capacity change valve 403 is not always satisfied during the operation of the cooling circuit, and the heating capacity change valve 403 is always closed during the operation of the cooling circuit. Or,
By cutting off the power supply to the solenoid 415, a high biasing force is applied to the plunger 413 by the spring 409a so that the valve body 409 is always closed regardless of the magnitude of the discharge pressure Pd.

During the operation of the cooling circuit, if the suction pressure Ps of the working fluid is not in the abnormally low pressure state, the cooling capacity change valve 3
Since the valve opening condition of 03 is not satisfied, the cooling capacity change valve 303 is closed. Of course, the discharge pressure of the working fluid during the operation of the cooling circuit does not satisfy the opening condition of the heating capacity change valve 403 (or the valve body 409 is forcibly closed by adjusting the energization to the solenoid 415). The heating capacity change valve 403 is closed. As a result, when the suction pressure Ps of the working fluid is not in the abnormally low pressure state, the working fluid is not discharged from the discharge chamber 120 to the drive chamber 110, and the capacity control is not performed.

On the other hand, if the suction pressure Ps of the working fluid becomes abnormally low during the operation of the cooling circuit, the opening condition of the cooling capacity change valve 303 is satisfied (the suction pressure Ps becomes a predetermined low pressure state). , The cooling capacity change valve 303 is opened. Of course, the discharge pressure of the working fluid during the operation of the cooling circuit does not satisfy the opening condition of the heating capacity change valve 403 (or the valve body 409 is forcibly closed by cutting off the power supply to the solenoid 415). , Heating capacity change valve 40
3 is closed. As a result, the valve body 305 of the cooling capacity change valve 303 moves in the valve opening direction, and the first and second cooling capacity change passages 321 and 322 are communicated. Then, the working fluid is discharged from the high pressure side discharge chamber 120 to the drive chamber 110 via the first cooling capacity change passage 321, the cooling capacity change valve 303, and the second cooling capacity change path 322. Will be. As a result, "the pressure Pc in the drive chamber 110 increases", "the swash plate 130 stands up (the inclination angle of the swash plate 130 decreases)", "the stroke of the piston 135 decreases", and "the discharge capacity decreases". Through a series of actions, the suction pressure Ps of the working fluid increases, and the abnormally low suction pressure Ps state is suppressed. Although the drive chamber 110 communicates with the suction chamber 115 via the pressure reducing passage 501, the suction pressure P
The working fluid is prevented from escaping from the drive chamber 110 to the suction chamber 115 before the abnormal low pressure countermeasure in s is completed.

The working fluid in the drive chamber 110 is sent little by little to the suction chamber 115 via the decompression passage 501, and is sent again to the cylinder bore 109 to be compressed, and then to the cooling circuit again via the discharge chamber 120 and the discharge port 121. Will be discharged.

Next, the capacity control during the operation of the heating circuit 152 (see FIG. 2) will be described. During the operation of the heating circuit 152, the capacity is controlled using the heating capacity changing means 401, and the cooling capacity changing means 301 is not used.
Therefore, for the heating capacity change valve 403, the solenoid 4
15 is appropriately adjusted, and the valve opening reference pressure of the valve element 409 is set so that the valve element 409 opens when the discharge pressure Pd of the working fluid reaches a predetermined reference value. The reference value relating to the discharge pressure Pd is set to an upper limit value in an appropriate range where an excessively high pressure is not applied to the heating circuit 152. That is, when the discharge pressure Pd exceeds the allowable upper limit value, it is determined that the discharge pressure Pd is in an abnormally high pressure state, and the capacity control by the heating capacity changing unit 401 is started. On the other hand, the cooling capacity change valve 303 is always closed during the operation of the heating circuit, so that the working fluid is not discharged from the discharge chamber 120 to the drive chamber 110 via the cooling capacity changing means 301. Specifically, the energization of the solenoid 309 is appropriately adjusted, and the valve opening reference pressure of the cooling capacity change valve 303 is set to be lower than the lower limit of the working fluid suction pressure Ps during the heating circuit operation. As a result, the valve opening reference pressure of the cooling capacity change valve 303 is not always satisfied during the operation of the heating circuit, and the cooling capacity change valve 403 is always closed during the operation of the heating circuit. Alternatively, by energizing the solenoid 309, a high biasing force is applied to the plunger 307 such that the valve body 305 is always closed regardless of the magnitude of the suction pressure Ps.

During the operation of the heating circuit, when the discharge pressure Pd of the working fluid is not in an abnormally high pressure state, the heating capacity change valve 4
Since the opening condition of 03 is not satisfied, the heating capacity change valve 403 is closed. Of course, the suction pressure of the working fluid at the time of operating the heating circuit does not satisfy the opening condition of the cooling capacity change valve 303 (or the valve body 305 is forcibly closed by increasing the power supply to the solenoid 309). The cooling capacity change valve 303 is closed. As a result, when the discharge pressure Pd of the working fluid is not in an abnormally high pressure state, the working fluid is only sent from the discharge chamber 120 to the heating circuit via the discharge port 121, and is discharged from the discharge chamber 120 to the drive chamber 110. Therefore, capacity control is not performed.

On the other hand, when the discharge pressure Pd of the working fluid becomes abnormally high during the heating circuit operation, the opening condition of the heating capacity change valve 403 is satisfied (the discharge pressure Pd becomes a predetermined high pressure state). The heating capacity change valve 403 is opened. Of course, the suction pressure of the working fluid at the time of operating the heating circuit does not satisfy the opening condition of the cooling capacity change valve 303 (or the valve body 305 is forcibly closed by increasing the power supply to the solenoid 309). , Cooling capacity change valve 3
03 is closed. As a result, the heating capacity change valve 403
Is moved in the valve opening direction, and the first and second heating capacity change passages 421 and 422 are communicated. Then, the working fluid is discharged from the high pressure side discharge chamber 120 to the drive chamber 110 via the first heating capacity change passage 421, the heating capacity change valve 403, and the second heating capacity change passage 422. Will be. As a result, "the pressure Pc in the drive chamber 110 increases", "the swash plate 130 stands up (the inclination angle of the swash plate 130 decreases)", "the stroke of the piston 135 decreases", and "the discharge capacity decreases". Through a series of actions, the discharge pressure Pd of the working fluid decreases, and the abnormally high discharge pressure Pd state is suppressed. Although the drive chamber 110 communicates with the suction chamber 115 via the pressure reducing passage 501, the working fluid is supplied to the drive chamber 110 before the abnormally high discharge pressure Pd countermeasures are completed due to the restriction provided in the pressure reducing passage 501. From the air to the suction chamber 115 is prevented.

The working fluid in the drive chamber 110 is sent little by little to the suction chamber 115 via the pressure reducing passage 501, and is again sent to the cylinder bore 109 to be compressed. Will be discharged.

The cooling capacity changing means 301 and the heating capacity changing means 401 are arranged independently and in parallel to control the communication / non-communication state between the discharge chamber 120 and the drive chamber 110. It has a configuration. During the operation of the cooling circuit, the capacity is controlled using only the cooling capacity changing means 301 (the heating capacity changing valve 403 is kept closed).
01 (only for the cooling capacity change valve 30)
3 is kept closed). In this manner, a form in which two capacity changing units are independently and parallelly arranged to perform capacity control is defined as a "parallel arrangement type" capacity control technique.

According to the air conditioner according to the present embodiment, the working fluid once pressurized by the variable capacity compressor 101 is discharged to the drive chamber 110, so that the energy efficiency is slightly deteriorated. The discharge capacity is reduced depending on the amount, the suction pressure is increased, and the discharge pressure is reduced. Since the working fluid is not thrown out of the heating circuit 152, no extreme energy loss occurs.
Further, a situation in which the working fluid for operating the heating circuit 152 runs short does not occur. That is, according to the present embodiment, in an air conditioner including a heating circuit that is a hot gas bypass heater, the working fluid in the heating circuit is discharged to the cooling circuit in order to suppress an abnormally high pressure state during the heating operation. In other words, there is no problem that the heating capacity is insufficient and that the working fluid which is caused to work by the compressor and is pressurized to a high pressure is wastefully discharged to the outside of the heating circuit, resulting in extremely low energy efficiency.

(First Modification of the Embodiment) A first modification of the embodiment is shown in FIG. This is a modified example in which the configuration of the heating capacity changing unit 401 is different. As shown in FIG. 4, in the variable displacement compressor 701 according to the present modification, the heating displacement changing means 601 is used.
However, the pilot passage 621 (corresponding to the first heating capacity change passage 421 of the above embodiment),
It comprises a pilot valve 619, a heating capacity change valve 603, and a second heating capacity change passage 422.
The discharge chamber 120 is connected to the pilot valve 619 through the first pilot passage 621a. Pilot valve 6
Reference numeral 19 is connected to the first compartment 605 of the heating capacity change valve 603 through the second pilot passage 621b. The heating capacity change valve 603 further includes a second compartment 6
07 is formed, and the second compartment 607 is connected to the drive room 110 via the second heating capacity change passage 422. A valve body 609 is arranged between the first compartment 605 and the second compartment 607. The valve element 609 is usually
Valve closing direction by spring 609a (right direction in FIG. 4)
To the first and second compartments 605, 6
07 is in a non-communication state. The valve element 609 is configured to be opened by a pressure difference between the pressure in the first compartment 605 and the pressure in the second compartment 607. That is, the heating capacity change valve 603 is configured as a differential pressure valve.
Normally, the pilot valve 619 is configured so that the first and second pilot passages 621a and 621b are not in communication with each other, and can move in the valve opening direction by energizing the solenoid 615. When moving in the valve opening direction, the first and second pilot passages 621a, 621
b is in a communication state.

Other structures, for example, the structure of the variable displacement compressor itself and the structure of the cooling capacity changing means 301 are the same as those of the above-described embodiment of the present invention, and the detailed description is omitted for convenience.

In the present modified example, during the operation of the cooling circuit, a measure for abnormally low suction pressure of the working fluid is taken only by the cooling capacity changing means 301, so that the heating capacity changing means 601 supplies the working fluid to the discharge chamber. 120 to drive room 110
Must not be released. Since the differential pressure itself cannot be controlled from the outside, the heating capacity change valve 603 having the structure of the differential pressure valve is opened carelessly during the operation of the cooling circuit, and interferes with the capacity control by the cooling capacity changing means 301. This is because there is a fear. Therefore, during the operation of the cooling circuit, the pilot valve 619 is forcibly closed (the state of FIG. 4), and the pilot passage 621 is set in the non-communication state. That is, during the operation of the cooling circuit, the pilot valve 61
9 is always closed, and the working fluid is
01 so as not to be discharged from the discharge chamber 120 to the drive chamber 110. The function of the cooling capacity changing means 301 during the operation of the cooling circuit is the same as that of the above-described embodiment, and a detailed description is omitted for convenience.

On the other hand, during the operation of the heating circuit, the pilot valve 619 is controlled so that the working fluid is sent from the discharge chamber 120 to the heating capacity change valve 603 so as to take measures against abnormally high pressure of the working fluid only by the heating capacity changing means 601. Must be open. Therefore, the solenoid 615 is energized and excited to open the pilot valve 619. As a result, the pilot passage 621 is in a communicating state, and the working fluid is sent from the discharge chamber to the first compartment 605. As a result, the pressure in the first compartment 605 is set to the discharge pressure Pd, and the pressure Pc in the drive chamber 110 guided into the second compartment 607 via the second heating capacity change passage 422. Acts on the valve element 609 together.

When the discharge pressure Pd of the working fluid is not in the predetermined high pressure state during the operation of the heating circuit, that is, when it is not in the abnormal high pressure state, the discharge pressure Pd in the first compartment 605
Does not overcome the resultant force of the biasing force of the spring 609a in the valve closing direction and the pressure Pc in the second compartment 607, and the heating capacity change valve 603 is closed. Further, similarly to the above-described embodiment of the present invention, the cooling capacity change valve 303 is always closed when the heating circuit operates. Therefore, the working fluid is not released from the discharge chamber 120 to the drive chamber 110,
No capacity control is performed.

When the discharge pressure Pd of the working fluid reaches a predetermined high pressure state during the operation of the heating circuit, that is, when the discharge pressure Pd reaches an abnormally high pressure state, the discharge pressure Pd in the first compartment 605 is increased by the spring 609a. Of the valve 6 against the resultant force of the urging force in the valve closing direction and the pressure Pc in the second compartment 607.
09 in the valve opening direction, and the heating capacity change valve 603 is opened. Of course, at this time, the cooling capacity change valve 303 is closed. As a result, the high-pressure working fluid in the discharge chamber 120 is supplied to the first pilot passage 621a, the opened pilot valve 619, the second pilot passage 621b, the opened heating capacity change valve 603, and the second heating passage. It is discharged to the drive chamber 110 via the capacity change passage 422, and by the same operation as described in the above embodiment,
The countermeasures against abnormally high discharge pressure Pd will be taken.

(Other Modifications) FIGS. 5 to 8 systematically show other possible modifications of the above-described "parallel arrangement type" capacity control technique.

In the parallel arrangement type capacity control technology, the discharge chamber 12
0 and the drive chamber 110, a suction pressure control capacity changing means 701 for taking measures against abnormally low suction pressure of the working fluid.
And a discharge pressure control capacity changing unit 702 for taking measures against abnormally high discharge pressure. As shown in FIG. 5, the suction pressure control capacity changing means 701 has a suction pressure control valve 711, and the discharge pressure control capacity changing means 702 has a discharge pressure control valve 712. In addition, a throttle 731 is arranged on a pressure reducing passage connecting the drive chamber 110 and the suction chamber 115. As shown in FIGS. 5 to 8, the discharge chamber 120 and the drive chamber 110 are basically connected by a single path, and each of the capacity changing units is provided in the middle of the path. Are arranged in parallel, and the discharge chamber 12
0 and the drive chamber 110 are connected by two separate routes, and the capacity changing means is arranged in the middle of each route. In the above-described embodiment and the first modification thereof, the latter mode (the mode in which each capacity changing unit is arranged in the middle of two separate paths) is used. Each control valve 71
For 1,712, it is possible to use a valve that can appropriately change the valve opening reference pressure by using a solenoid or the like based on the configuration of the differential pressure valve, or a valve that can forcibly control opening and closing by external control. it can. Such a valve structure is defined as an “external control valve”. Each control valve 711, 712 is provided with a differential pressure between the suction pressure Ps of the working fluid and other pressures (for example, atmospheric pressure, vacuum pressure).
Alternatively, the discharge pressure Pd of the working fluid and other pressures (eg, atmospheric pressure, vacuum pressure, pressure Pd in the drive chamber, suction pressure Ps)
And a differential pressure valve that is opened and closed by the differential pressure between Such a valve structure is defined as “internal control valve”. The term "inside" is used because it typically uses a differential pressure valve that opens and closes due to the pressure difference within the air conditioner. With the internal control valve, its opening and closing conditions depend on two pressure relationships, and the structure of the device is simplified, but its opening and closing cannot be controlled by an external operation.

When capacity control is performed using an external control valve, the external control valve is opened and closed in accordance with the pressure state of the working fluid suction pressure or discharge pressure, and the other capacity changing means controls the capacity control. When performing this operation, the valve is closed so that the other capacity changing means does not inadvertently interfere with the capacity control. FIG. 5 shows a system diagram in the case where external control valves are employed for both the control valves 711 and 712.

On the other hand, when the internal control valve is used as the capacity changing means, the open / close condition of the internal control valve depends on two pressure relationships (typically, two pressure relationships in the air conditioner) as described above. Since the opening and closing cannot be controlled by an external operation, it is inadvertently opened during the capacity control by the other capacity changing means, and interferes with the capacity control assigned to the other capacity changing means. There is a risk. Therefore, a pilot valve is arranged on the upstream side of the internal control valve, and at the time of displacement control, the pilot valve is opened so that working fluid is sent to the control valve, and when the other displacement changing means performs displacement control, the pilot valve is closed. Sisters,
The capacity control by the other capacity changing means is not hindered.

FIG. 6 shows a suction pressure control capacity changing means 701.
In which a control valve 711 configured as an internal control valve and a pilot valve 711a are disposed upstream of the control valve 711, and a control valve 712 configured as an external control valve is disposed in the discharge pressure control capacity changing means 702. Is shown.

FIG. 7 shows a suction pressure control capacity changing means 701.
In which a control valve 711 configured as an external control valve is disposed, and a control valve 712 configured as an internal control valve and a pilot valve 712a disposed upstream thereof are disposed in the discharge pressure control displacement changing means 702. Is shown.

FIG. 8 shows a suction pressure control capacity changing means 701.
Both the discharge pressure control displacement changing means 702 and control valves 711 and 712 configured as internal control valves and pilot valves 711a and 712a disposed on the upstream side are shown.

The above-described embodiment relates to the control mode shown in FIG. 5 (parallel arrangement type capacity control both configured as external control valves).
(Parallel arrangement type capacity control using an external control valve for suction pressure control and an internal control valve and a pilot valve arranged upstream thereof for discharge pressure control) . Of course, the control configuration shown in FIG. 6 (parallel arrangement type capacity control using an internal control valve and a pilot valve arranged upstream thereof for suction pressure control and an external control valve for discharge pressure control), It is possible to adopt the control mode shown in FIG. 8 (both the suction pressure control and the discharge pressure control, a parallel arrangement type control using an internal control valve and a pilot valve arranged upstream thereof). 6 to 8, it is also possible to arrange the pilot valve downstream of the internal control valve.

In this embodiment and its modified example,
Although the cooling capacity change means and the heating capacity change means are both provided inside the variable displacement compressor, all or some of them may be provided outside the variable displacement compressor. Good. Further, the number of pistons of the variable displacement compressor may be changed, or the pistons may be arranged on both sides of the swash plate instead of one side.

[0063]

The present invention is directed to an air conditioner disclosed in Japanese Patent Application Laid-Open No. 7-19630 by applying a discharge capacity control technique of a conventional variable displacement compressor to an air conditioner having a hot gas bypass heater circuit. The problem of the technology for countermeasures against abnormal high pressure in the device, that is, the problem that the working fluid in the hot gas bypass heater circuit is released to the cooling circuit and the heating capacity is insufficient, and the operation that the compressor works to increase the pressure to high pressure The problem that energy efficiency is poor due to wasteful discharge of fluid out of the heating circuit has been solved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the structure of a conventional air conditioner.

FIG. 2 is a sectional view schematically showing a structure of an air conditioner according to the present embodiment.

FIG. 3 is a cross-sectional view illustrating a detailed structure of a variable displacement compressor and a capacity changing unit in the air conditioner according to the present embodiment.

FIG. 4 is a diagram showing a first modification of the present embodiment.

FIG. 5 is a system diagram showing another modification of the embodiment.

FIG. 6 is a system diagram showing a modification of the present embodiment.

FIG. 7 is a system diagram showing a modification of the present embodiment.

FIG. 8 is a system diagram showing a modification of the present embodiment.

[Explanation of symbols]

 101 Variable displacement compressor 110 Drive chamber 115 Suction chamber 120 Discharge chamber 125 Drive shaft 130 Swash plate 135 Piston 301 Cooling capacity changing means 303 Cooling capacity changing valve 321 First cooling capacity changing passage 322 Second cooling capacity Change passage 401 Heating capacity change means 403 Heating capacity change valve 405 First compartment 407 Second compartment 421 First heating capacity change passage 422 Second heating capacity change passage 619 Pilot valve 621 Pilot passage

Claims (9)

[Claims] 1. A compressor having a compressor, a cooling circuit, a heating circuit, and a capacity changing means, wherein the compressor has a suction part for sucking a working fluid, and a discharge part for discharging a compressed working fluid. A driving unit that is provided in the driving chamber and reduces the discharge capacity when the pressure in the driving chamber increases.The cooling circuit includes a capacitor disposed on a path from the discharge unit to the suction unit. A heat exchanger disposed downstream of the condenser, the heating circuit includes a bypass from the discharge section to the heat exchanger, and the heat exchanger; and the capacity changing unit includes: A first and a second capacity changing unit for setting the discharge unit and the drive chamber to be in a communication state or a non-communication state, respectively, wherein the first and the second capacity change unit are configured to include the discharge unit and the drive chamber. Parallel to the passage to communicate with The first displacement changing means is arranged to establish a communication state between the discharge section and the drive chamber when the suction pressure of the working fluid becomes a predetermined low pressure state, and the second displacement changing means operates An air conditioner, wherein when the discharge pressure of the fluid becomes a predetermined high pressure state, the discharge part and the drive chamber are brought into a communication state. 2. The air conditioner according to claim 1, wherein the first capacity changing unit is disposed in a passage connecting the discharge unit and a drive chamber, and a working fluid is provided when the cooling circuit is operated. A first capacity change valve that is opened when the suction pressure of the liquid supply reaches a predetermined low pressure state, wherein the second capacity change means is disposed in a passage communicating the discharge unit and the drive chamber, and An air conditioner comprising: a second capacity change valve that opens when the discharge pressure of the working fluid reaches the predetermined high pressure state during operation of the heating circuit. 3. The air conditioner according to claim 2, wherein the first and second capacity change valves are provided in a housing of the compressor. 4. The air conditioner according to claim 2, wherein the first and second capacity change valves are capable of changing a valve opening reference pressure. . 5. The air conditioner according to claim 4, wherein the first capacity change valve is opened when a suction pressure of the working fluid falls below a valve opening reference pressure, and the second capacity change valve is used for the working fluid. When the cooling circuit operates, the valve opening reference pressure of the first capacity change valve is set to the lower reference value of the working fluid suction pressure during the cooling circuit operation. Set, the valve opening reference pressure of the second capacity change valve is set higher than the upper limit reference value of the discharge pressure of the working fluid at the time of operating the cooling circuit, and at the time of operating the heating circuit, The valve opening reference pressure is set lower than the lower limit reference value of the suction pressure of the working fluid when the heating circuit operates, and the valve opening reference pressure of the second capacity change valve is set to the upper reference value of the discharge pressure during the heating circuit operation. An air conditioner characterized by being performed. 6. The air conditioner according to claim 4, wherein the reference valve opening pressure of the first and second capacity change valves is determined by exciting a solenoid provided in each of the capacity change valves. An air conditioner characterized by being changed through non-excitation. 7. The air conditioner according to claim 2, wherein the capacity change valve in the first and / or second capacity change means includes a suction pressure of the working fluid and a pressure other than the suction pressure. Or by a differential pressure between the discharge pressure of the working fluid and a pressure other than the discharge pressure, and on the path from the discharge section to the drive chamber on the upstream side of the capacity change valve. An air conditioner characterized by having a pilot valve. 8. The air conditioner according to claim 7, wherein the pilot valve is open when the capacity control by the capacity changing means is performed, and the capacity control is performed by the other capacity changing means. An air conditioner characterized by being closed when in operation. 9. The air conditioner according to claim 8, wherein the pilot valve is opened and closed via energization or non-excitation of a solenoid.