JP2005098208A - Scroll compressor and air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scroll compressor and an air conditioner capable of driving a gas engine for driving the scroll compressor in a high efficiency region at an appropriate torque. <P>SOLUTION: The air conditioner 1 has a scroll compressor 12 having a fixed scroll and a turning scroll. By turning of the turning scroll, a compression body is taken in into a compression chamber between the fixed scroll and the turning scroll from a suction port 21 on the outer edge, the compression chamber is transferred from the outer side to the inner side, and the compression body is compressed. The scroll compressor 12 is provided with a suction amount adjusting port 23 provided in a position communicable with the suction port 21 by the same compression chamber, capable of switching from being opened and closed by an opening/closing valve 17. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an air conditioner that circulates a refrigerant to perform indoor air conditioning and a scroll compressor used in the air conditioner. More specifically, the present invention relates to a scroll compressor driven by a gas engine and air conditioning equipment.

  2. Description of the Related Art Conventionally, there has been an air conditioner that performs indoor air conditioning by providing heat exchangers both indoors and outdoors and circulating refrigerant while changing the phase between them. In such an air conditioner, a compressor for compressing a refrigerant in a low-pressure gas state into a high-pressure gas state is used. Some compressors use a gas engine driven scroll compressor. In the scroll compressor, a spiral orbiting scroll disposed between spiral fixed scrolls is swirled to reduce the volume of the compression chamber inside. In this compressor, the required engine torque is determined by the gas pressure difference between the suction port and the discharge port and the gas discharge amount. Therefore, the required engine torque varies considerably depending on the temperature difference from the set temperature of the air conditioner or the outside air temperature.

In general, in a gas engine that drives the scroll compressor, the rotational speed is changed according to the load, and the shaft torque of the engine is controlled to be substantially constant. However, gas engines have a limited variable speed range (range of operating speeds). For this reason, it was not possible to adequately cope with loads that varied greatly, especially when the load became very small. Therefore, an air conditioner in which an opening is provided in the intermediate pressure portion of the compressor has been proposed (see, for example, Patent Document 1). In this air conditioner, when the load is small, the refrigerant gas flows out from the opening of the compressor to the low pressure flow path. This improves controllability when the air conditioning load is small.
JP-A-10-115292

  However, in general, in a gas engine, if the work is the same, the higher torque region is a more efficient operation region, so low torque work is a less efficient operation region. As in the conventional air conditioner described above, when the compressor load is reduced when the air conditioning load is small and the torque applied to the compressor driving engine is also reduced, the engine operating efficiency is also lowered at the same time. It was.

  Here, FIG. 8 shows an example of a maximum torque curve of a general gas engine. As shown in FIG. 8, the maximum torque of the gas engine varies depending on its rotational speed, and the rotational speed shows a peak near the center of the change range, and gradually decreases at higher rotational speeds. The standard of the engine to be used is selected based on the fact that it does not stall even when the air conditioning load becomes maximum, and the engine shaft torque that is the control value is the engine standard value (maximum torque) even at the maximum load. It is set so that there is some margin. That is, the standard for selecting the engine standard is when the load is high (for example, a high rotation region of about 2000 rpm), and the maximum torque at this time is about 10 to 20% lower than the peak. The shaft torque as the control value has a predetermined margin with respect to the maximum load and is determined, for example, as shown by a one-dot chain line in FIG. 8, so that it is driven in a medium speed rotation region of about 1000 to 1600 rpm. Sometimes it is much smaller than the maximum torque. Therefore, a scroll compressor and an air conditioner that can be driven in a high torque region, which is a higher efficiency region for the engine, have been desired.

  The present invention has been made to solve the problems of the conventional scroll compressor and air conditioner described above. That is, an object of the present invention is to provide a scroll compressor and an air conditioner that can drive a gas engine that drives the scroll compressor in a high efficiency region with appropriate torque.

  The scroll compressor of the present invention, which has been made for the purpose of solving this problem, has a fixed scroll and an orbiting scroll, and the orbiting scroll is swung, so that the compression chamber between the fixed scroll and the orbiting scroll is passed through the suction port at the outer end. A scroll compressor that takes in the object to be compressed and moves the compression chamber from the outside to the inside to compress the object to be compressed, and is provided at a position where it can communicate with the suction port by the same compression chamber, and can be switched between open and closed It has an inhalation amount adjusting port.

  According to the scroll compressor of the present invention, the suction amount adjustment port that can be switched between open and close is provided, and the suction amount adjustment port is provided at a position that can be communicated with the same compression chamber as the suction port that takes in the object to be compressed. . That is, when the suction amount adjusting port is in the open state, the compression chamber located at the position including the suction amount adjusting port is communicated with the suction port, so that the internal compression target is not compressed. The compression does not proceed until the compression chamber is moved inward from the suction amount adjusting port. Therefore, since the pressure difference between the suction port and the discharge port is small and the load is low, the engine operates at a low torque. On the other hand, if the intake amount adjusting port is in the closed state, the compression proceeds from the beginning and the load is high, so the engine operates at a high torque. In other words, this scroll compressor can be operated with different required loads, and by selecting them according to the size of the air conditioning load, the gas engine that drives the scroll compressor can be operated in a high-efficiency range with appropriate torque. It can be driven.

  The air conditioner of the present invention includes a refrigerant flow path, a compressor that circulates the refrigerant in the refrigerant flow path, and a prime mover that drives the compressor. The compressor includes a fixed scroll and a turning scroll, and the turning scroll. This is a scroll compressor that takes in the object to be compressed from the suction port at the outer end into the compression chamber between the fixed scroll and the orbiting scroll, and compresses the object to be compressed by moving the compression chamber from the outside to the inside. The compression chamber is provided at a position where it can communicate with the suction port, and has a suction amount adjustment port that can be switched between open and closed.

  According to the air conditioner of the present invention, the load can be switched because the scroll compressor has the suction amount adjusting port that can be switched between open and closed. Therefore, the engine can be selected from two types of operation modes, high torque and low torque. Therefore, by selecting according to the size of the air conditioning load, it is possible to select and operate an efficient region.

Further, in the air conditioner of the present invention, as the operation mode, the scroll compressor intake amount adjustment port is opened, the prime mover is operated at low torque, the scroll compressor intake amount adjustment port is closed, It is desirable to have a high efficiency operation mode in which the prime mover is operated at high torque.
In this way, when the air-conditioning load is large and the engine is driven at a high rotational speed, there is no allowance for torque, so the operation is performed in the low torque operation mode. On the other hand, when the air conditioning load is medium and the engine is driven at a medium speed, the maximum torque of the engine is large, so that high torque operation can be performed. Since high torque operation is high efficiency operation, this operation mode can be said to be a high efficiency operation mode.

  According to the scroll compressor and the air conditioner of the present invention, the gas engine that drives the scroll compressor can be driven in a high-efficiency region with appropriate torque.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below in detail with reference to the accompanying drawings. In the present embodiment, the present invention is applied to an air conditioner that circulates a refrigerant and performs indoor air conditioning and a scroll compressor used in the air conditioner.

  As shown in FIG. 1, the air conditioner 1 of the present embodiment has a gas engine 11, a scroll compressor 12, two heat exchangers (condenser 13 and evaporator 14), and an expansion valve 15. ing. These components are connected to each other by the refrigerant flow path 16, and the refrigerant is circulated through the refrigerant flow path 16. The scroll compressor 12 is provided with a suction port 21, a discharge port 22, and a suction amount adjustment port 23, and an opening / closing valve 17 is provided between the suction amount adjustment port 23 and the refrigerant flow path 16.

  The gas engine 11 drives the scroll compressor 12 by rotating a rotating shaft using gas such as city gas as fuel. The condenser 13 releases heat and condenses (liquefies) the refrigerant. The evaporator 14 absorbs heat and evaporates (vaporizes) the refrigerant. The expansion valve 15 depressurizes the liquid refrigerant. These configurations are the same as those of a conventional air conditioner. The scroll compressor 12 will be described later. In addition to this configuration, the air conditioner 1 further requires various valves, an accumulator, and the like.

  When the refrigerant is circulated through the air conditioner 1 as shown by the arrows, the state changes as follows. The refrigerant discharged from the discharge port 22 of the scroll compressor 12 in the high pressure gas state is liquefied by the condenser 13. At this time, heat is released from the condenser 13. And the refrigerant | coolant which became the high pressure liquid state is pressure-reduced by the expansion valve 15, and will be in a low pressure liquid state. Further, it is vaporized by the evaporator 14 to be in a low pressure gas state. At this time, heat is absorbed by the evaporator 14. Thereafter, the refrigerant enters the scroll compressor 12 again from the suction port 21 and is compressed and discharged in a high-pressure gas state. Therefore, during cooling, the evaporator 14 is an indoor unit and the condenser 13 is an outdoor unit. During heating, the evaporator 14 is an outdoor unit, and the condenser 13 is an indoor unit.

  Next, the scroll compressor 12 will be described. Inside the scroll compressor 12, as schematically shown in FIG. 2, a spiral orbiting scroll 25 orbits between the spiral fixed scrolls 24. The lower part of each figure shows the turning angle when the upper left state is 0 degree. At the turning angle of 360 degrees, the arrangement of the turning scroll 25 returns to the same state as at the turning angle of 0 degree. As shown in FIG. 2, the scroll compressor 12 is provided with two suction ports 21, one discharge port 22, and two suction amount adjustment ports 23. The suction port 21 communicates between the end of the fixed scroll 24 and the orbiting scroll 25 and between the end of the orbiting scroll 25 and the fixed scroll 24. The discharge port 22 communicates with the central compression chamber. Further, the suction amount adjusting port 23 is provided so as to communicate with the compression chamber at a position inside about 135 degrees from the end of the fixed scroll 24 and its point-symmetrical position.

  The compression chamber when the on-off valve 17 is closed and the two intake amount adjusting ports 23 are closed changes as the orbiting scroll 25 turns as shown in FIG. That is, the volume of the compression chamber surrounded by the fixed scroll 24 and the orbiting scroll 25 of the scroll compressor 12 is reduced while the position is changed by the orbiting of the orbiting scroll 25. Assuming that the ratio of the volume change of the compression chamber to the swirl angle is almost constant as shown in the graph of FIG. 3, the compression chamber having a swivel angle of 0 ° and a volume of 100% is 45% at the swirl angle of 720 °. It will be about. The scroll compressor 12 can compress up to a turning angle of about 1080 degrees (three rounds), and in that case, the volume is compressed to about 20%.

  Next, when the on-off valve 17 is opened, the suction port 21 and the suction amount adjustment port 23 are in communication with each other as shown in FIG. That is, the low-pressure gas refrigerant vaporized by the evaporator 14 flows into the suction port 21 and the suction amount adjustment port 23. In this state, the compression chamber that is point-hatched in FIG. 2 communicates with the suction amount adjusting port 23 between the swivel angles of 0 ° and 90 °, so that it also communicates with the suction port 21 and refrigerant flows into the compression chamber. And compression does not proceed. Compression is performed only when the turning angle is 135 degrees or more. This means that the compression starts after the volume of the compression chamber reaches about 90% from the graph of FIG. Therefore, since the suction amount of the scroll compressor 12 is reduced to about 90%, the refrigerant discharge amount of the discharge port 22 is smaller than that when the on-off valve 17 is closed, and the torque required for compression is also small. From this, it can be said that in the scroll compressor 12, the magnitude of the load can be changed to two types by opening and closing the on-off valve 17.

  By the way, in FIG. 2, the suction adjusting port 23 is provided at a position inside about 135 degrees from the end of the fixed scroll 24 and at a substantially point-symmetrical position thereof. The position about 135 degrees inside from the end of the fixed scroll 24 is the inside in contact with the fixed scroll 24 at an angle (135 degrees) indicated by a broken line, as shown in FIG. Here, this angular position is not limited to 135 degrees. Any position can be used as long as it can communicate with the suction port 21 through the same compression chamber, and the position range thereof is a range indicated by dot hatching in FIG. 4 (A), as shown in FIG. 4 (B). This corresponds to an inner position (range 31) of less than 360 degrees from the end of the fixed scroll 24. That is, one of the suction adjustment ports 23 is provided at one place on the line of the range 31. The other one is provided at a substantially point-symmetrical position, and the position range is a range 32 shown in FIG. In FIG. 4B, the orbiting scroll 25 is omitted, and only the arrangement range of the fixed scroll 24 and the suction adjustment port 23 is shown.

  Furthermore, since the rate of change in the suction amount of the scroll compressor 12 varies depending on the position of the suction adjustment port 23 (angle from the end), the position is selected so that the desired suction amount is obtained. For example, in the case of the scroll compressor 12 whose volume reduction rate is represented by the graph of FIG. 3, in order to make the suction amount about 70%, to make the suction amount around 350 degrees from the end, and to make the suction amount about 95%. What is necessary is just to provide the suction | inhalation adjustment port 23 in 45 degree vicinity from an edge part. In FIG. 2, the suction adjustment port 23 is shown to be quite large for the sake of clarity. However, in actuality, the suction adjustment port 23 is a very small diameter or elongated hole, and is formed in a size that is blocked by the thickness of the orbiting scroll 25. .

  Next, a control method of the air conditioner 1 will be described. As shown in FIG. 7, the maximum torque curve of the gas engine 11 changes to a mountain shape similar to the conventional one. Here, it is assumed that the engine shaft torque is t1 (Nm) when the on-off valve 17 is opened and the scroll compressor 12 has a low load and the engine has a low torque. Further, the engine shaft torque is t2 (Nm) when the on-off valve 17 is closed and the scroll compressor 12 has a high load and the engine has a high torque. Here, the scroll compressor 12 is selected so that when the on-off valve 17 is in the open state, the size or the compression rate is the same as that of the compressor in the conventional air conditioner.

  When the difference between the outside air temperature and the set temperature is large and the air conditioning load is large, the gas engine 11 is used in a region where the rotational speed is large. In FIG. 7, the operation is performed in a region where the engine speed is larger than r4 (rpm). In this region, there is little room for the maximum torque of the gas engine 11. Therefore, as shown in FIG. 5, the on-off valve 17 is opened, and the gas engine 11 is operated at a low torque with the engine shaft torque t1 (Nm). This mode is the low torque operation mode. This is an operation in the same area as the conventional operation.

  On the other hand, when the air conditioning load is slightly small and the engine speed is r4 (rpm) or less in the low torque operation mode, the operation mode of the gas engine 11 is changed. In this region, the margin to the maximum torque is increased, so high torque operation is performed. That is, as shown in FIG. 6, the on-off valve 17 is closed and the gas engine 11 is controlled to operate with the engine shaft torque t2 (Nm). This is drive control at high torque and low rotational speed. In general, the gas engine 11 is operated in a high efficiency region because the high torque region is a high efficiency region for the same work amount. Therefore, this mode is a high efficiency operation mode.

  At the change of these modes, as shown in FIG. 7, the rotational speeds r2 and r3 (rpm) are selected so that the work amounts are equal. Note that it is not desirable to rotate the gas engine 11 below the minimum rotational speed. Therefore, when the air-conditioning load is further reduced and the engine speed is the minimum in high torque operation, the on-off valve 17 is opened and the low torque operation mode is set to low torque and low speed operation.

  As described above in detail, according to the air conditioner 1 of the present embodiment, the refrigerant flow path 16, the scroll compressor 12 that circulates the refrigerant in the refrigerant flow path 16, the gas engine 11 that drives the scroll compressor 12, It is operated in the low torque operation mode or the high efficiency operation mode. In other words, when the air conditioning load is small to some extent, there is a margin to the maximum torque of the engine, so the on-off valve 17 is closed and the operation is performed at a high torque. Since the gas engine 11 is generally highly efficient in a high torque region, this is an operation in a high efficiency operation mode. Therefore, in this air conditioner 1, the gas engine 11 that drives the scroll compressor 12 can be driven in a high efficiency region with appropriate torque. Alternatively, when the air conditioning load is large, the on-off valve 17 is opened and the operation in the low torque operation mode is performed.

Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof.
For example, in the above-described embodiment, the operation is performed in the low torque operation mode in the high rotation region, but the operation can be performed with the highest possible torque even in the high rotation region. However, in this case, since the torque margin becomes small, the on-off valve 17 is opened when the torque change is constantly monitored and the torque becomes insufficient. As a result, the mode can be instantaneously switched to the low torque operation mode, so that the scroll compressor 12 can be used as a means for preventing engine stall.
Further, for example, an intermediate pressure port may be further provided in the scroll compressor 12, and the refrigerant gas may be flowed out therefrom to adjust the load of the scroll compressor 12.

It is a block diagram which shows schematic structure of the air conditioning apparatus which concerns on this Embodiment. It is explanatory drawing which shows the mode of the compression chamber of a scroll compressor. It is a graph which shows the volume change of the compression chamber of a scroll compressor. It is explanatory drawing which shows the mode of the compression chamber of a scroll compressor. It is a block diagram which shows the mode of driving | running of an air conditioner in low torque operation mode. It is a block diagram which shows the mode of operation | movement in a highly efficient operation mode of an air conditioner. It is a graph which shows the maximum torque curve of a gas engine. It is a graph which shows the maximum torque curve of a gas engine.

Explanation of symbols

1 Air conditioner 11 Gas engine (motor)
12 Scroll compressor 16 Refrigerant flow path 17 On-off valve 21 Suction port 23 Suction amount adjustment port

Claims (3)

A fixed scroll and an orbiting scroll, and by the orbiting of the orbiting scroll, the object to be compressed is taken into the compression chamber between the fixed scroll and the orbiting scroll from the suction port at the outer end, and the compression chamber is moved from the outside to the inside. In a scroll compressor that moves and compresses the object to be compressed,
A scroll compressor characterized in that it is provided at a position where it can communicate with a suction port by the same compression chamber, and has a suction amount adjusting port which can be switched between open and closed. A refrigerant flow path, a compressor that circulates the refrigerant in the refrigerant flow path, and a prime mover that drives the compressor,
The compressor is
A fixed scroll and an orbiting scroll, and by the orbiting of the orbiting scroll, the object to be compressed is taken into the compression chamber between the fixed scroll and the orbiting scroll from the suction port at the outer end, and the compression chamber is moved from the outside to the inside. It is a scroll compressor that moves and compresses the object to be compressed.
An air conditioner provided with a suction amount adjusting port which is provided at a position where it can communicate with the suction port by the same compression chamber and which can be switched between open and closed. In the air conditioner according to claim 2,
As operation mode,
A low-torque operation mode in which the suction amount adjustment port of the scroll compressor is opened and the prime mover is operated at a low torque;
An air-conditioning apparatus comprising: a high-efficiency operation mode in which the suction amount adjusting port of the scroll compressor is closed and the prime mover is operated at a high torque.

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