JPH0636912U - Automotive air conditioner capacitors - Google Patents

Abstract

(57) [Summary] [Purpose] While reducing the amount of refrigerant to be filled, the stability of the cycle can be ensured even with changes in the amount of filled refrigerant, and a stable supply of subcooled liquid refrigerant can be supplied to the expansion valve. It is an object of the present invention to provide a compact condenser for an air conditioner for an automobile. [Structure] A supercooling condenser is provided integrally with the multi-flow type body condenser, and a liquid tank is installed between both condensers.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a multi-pass condenser incorporated in an air conditioner for an automobile, and more particularly to a condenser provided integrally with a supercooling condenser.

[0002]

[Prior art]

 Generally, in the cooling operation of an automobile air conditioner, as is well known, the high-temperature and high-pressure vaporized refrigerant discharged from the compressor is condensed by a condenser, and this liquid refrigerant is supplied to an evaporator through an expansion valve. Heat is exchanged with air, and the air cooled by the refrigerant is blown into the passenger compartment.

If the heat load received by the evaporator changes, the amount of refrigerant supplied to the evaporator is adjusted by controlling the opening of the expansion valve, and when excess refrigerant is generated, it is provided in the downstream region of the capacitor. The liquid is temporarily stored in the liquid tank, and when the refrigerant is insufficient, the stored refrigerant in the liquid tank is discharged to the evaporator.

However, the refrigerant in the cooling cycle may leak to the outside of the cooling cycle during long-term use, or excess refrigerant may be sealed in the cooling cycle in some cases, so that the refrigerant in the cooling cycle always has a predetermined amount. It does not always exist. However, even in such a case, the refrigerant storage function of the liquid tank or the refrigerant storage function of the condenser itself makes it possible to perform a somewhat normal cooling operation, that is, a cooling operation with a predetermined subcool (supercooling degree). ing.

[0005]

[Problems to be solved by the device]

 However, recent condensers have a smaller overall size and are of so-called multi-pass type so that the refrigerant flows while making a U-turn in the condenser, thereby achieving miniaturization and high performance.

As shown in FIGS. 10 and 11, a recent capacitor 10 is a straight flat tube with both ends open between a pair of header pipes 11 and 12 that are spaced apart by a predetermined length and are arranged in parallel. A large number of parallel pipes 13 are provided so as to communicate with the header pipes 11 and 12, and heat transfer fins f are interposed between the flat pipes 13 to form a core portion 14. Both ends of each of the header pipes 11 and 12 are sealed by a lid 15, and one header pipe 11 has an inlet pipe 16 into which the refrigerant flows, and the other header pipe 12 has an outlet pipe 17 from which the refrigerant flows. Are installed respectively. A partition plate 18 is provided in each of the header pipes 11 and 12, and the refrigerant flowing from the inlet pipe 16 passes through the header pipes 11 into the plurality of flat pipes 13 and meanders in the core 14. And flows out from the outlet pipe 17. That is, it is a so-called multi-pass type multi-flow type in which a large number of paths (hereinafter, referred to as paths) through which the refrigerant flows from one header pipe 11 to the other header pipe 12 are formed.

A bracket 19 is attached to the header pipe 12, and a liquid tank 20 is supported by the bracket 19. As shown in FIG. 11, the liquid tank 20 has a main body 21 communicating with the outlet pipe 17, a desiccant 22 provided in the main body 21, and a penetrating penetrating desiccant 22 to the vicinity of the bottom of the main body 21. The refrigerant take-out pipe 23 and the refrigerant take-out pipe 23 are communicated with the expansion valve 24.

As described above, the recent condenser 10 is a multi-pass type in which a large amount of refrigerant is caused to flow collectively by a plurality of flat tubes 13 and is also meandered in the core 14, so that the condenser 10 is small in size. It is a high-performance capacitor with high heat exchange performance.

Further, recently, from the viewpoint of protecting the global environment, there is a demand to reduce the amount of refrigerant used. For this reason, we are trying to reduce the amount of refrigerant used for automobile air conditioners as well, but if a small amount of refrigerant is flowed using the high-performance condenser described above, it will not be affected by slight fluctuations in heat load. However, the state of the refrigerant in the condenser may fluctuate, the cooling operation with a predetermined subcooling (supercooling) may not be performed stably, and the temperature in the passenger compartment may fluctuate.

For example, when the amount of the refrigerant enclosed is close to or slightly small, the refrigerant only liquefies at the outlet portion of the condenser, and the subcool cannot be sufficiently obtained. Therefore, the refrigerant in the condenser is in a saturated state of gas-liquid mixing, and is in an unstable state in which the refrigerant is gasified by slight heat reception or pressure loss received by the outlet pipe and the like.

Therefore, in reality, the refrigerant flowing into the expansion valve is in a so-called hunting state in which the liquid state and the gas state are repeated alternately, the cooling performance of the evaporator is lowered, and the air blown into the vehicle interior is reduced. The temperature (hereinafter T value) also changes.

Further, when the amount of refrigerant to be filled is slight, the liquid refrigerant is used up to the final distribution path (hereinafter, the final path) after the refrigerant has meandered and circulated in the condenser, and is also used in the liquid tank. The liquid refrigerant is full. In this state, the liquid refrigerant in the final pass of the condenser is supercooled by the air, so the refrigerant is subcooled and flows into the expansion valve even if there is a slight heat reception to the outlet pipe etc. or some pressure loss. The refrigerant does not hunt and the refrigerant discharge pressure of the compressor, that is, the pressure of the refrigerant at the inlet of the condenser (Pd value below) rises slightly, but the cooling performance of the evaporator improves and the cycle is stable. However, cold power is also secured.

However, this state is one point, and if the amount of the refrigerant decreases even a little, the state becomes unstable, which is not practical.

When a capacitor having different performance depending on the amount of the filled refrigerant is miniaturized and has higher performance, this tendency becomes more remarkable, and the amount of the filled refrigerant is adjusted so as to obtain the above-mentioned slight refrigerant overfilled state. Even so, it is difficult to maintain this state, and it is more difficult to secure cycle stability with respect to changes in the refrigerant charge amount.

In this respect, in a large vehicle such as a bus, a sub-cool condenser is provided separately from an ordinary condenser so that the sub-cool can be sufficiently taken and the stability of the cycle against changes in the refrigerant charge amount is secured. However, this is possible because large vehicles have a sufficient space, and a subcool condenser is provided separately from the condenser in an ordinary passenger car that does not have a large space. It is not possible.

There is also a refrigerant in which the refrigerant is overfilled to some extent and excess liquid refrigerant generated during operation is stored in a portion other than the heat exchange area of the capacitor so that the condenser function of the condenser is not diminished. For example, a refrigerant storage tank is provided in the lower part of the condenser in communication with the inlet and the outlet (see Japanese Utility Model Laid-Open No. 2-38,055), and a part of the header pipe on the outlet side of the condenser has a large diameter. There is a thing (see the actual opening and closing No. 2-48,765). However, if this is done, it is not possible to reduce the amount of refrigerant charged, and since there is no subcool condenser independent of the condenser, a stable supply of subcooled liquid refrigerant is provided to the expansion valve. Is difficult.

The present invention has been made in view of the above problems, and it is possible to secure the cycle stability even when the amount of the filled refrigerant is changed while reducing the amount of the filled refrigerant, and the expansion valve has a sub-cooler. An object of the present invention is to provide a compact condenser for an air conditioner for an automobile, which is capable of stably supplying a well-balanced liquid refrigerant.

[0018]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention forms a core part by providing header pipes at both ends of a large number of flat tubes arranged in parallel with heat transfer fins interposed therebetween. A multi-pass type multi-flow type main body condenser is provided in which a partition plate is provided in the header section so that the fluid to be exchanged, which has flowed in from the inlet tube, meanders down in the core section until it reaches the outlet tube. By providing a plurality of flat tubes between the extension header pipes formed by extending the header pipe of this main body condenser, the supercooling condenser is formed integrally with the main body condenser, and the outlet side header of the main body condenser The end of the conduit, which is provided so as to communicate with the pipe, is provided so as to communicate with the inlet of the liquid tank and one of the header pipes of the supercooling condenser. A capacitor of an automotive air conditioning system, characterized in that attached each end of Shirubesuga the outlet of the liquid tank.

[0019]

[Action]

 In the present invention thus configured, the supercooling condenser is provided integrally with the main body condenser, so that the entire condenser has a compact structure and the liquid tank is installed between both condensers. It is not necessary to take a sub-cooling in the part, and the amount of the enclosed refrigerant in the cycle can be reduced, and even if the amount of the enclosed cooling medium changes a little, if the liquid refrigerant is stored in the liquid tank, The subcool can be reliably taken when is guided to the supercooling condenser. Therefore, even if there is a slight heat reception or some pressure loss, the subcooled liquid refrigerant is always introduced as the refrigerant flowing into the expansion valve, and the cycle operates stably even if the amount of refrigerant filled changes. The cooling performance of the evaporator is also improved.

[0020]

【Example】

 Hereinafter, embodiments according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a condenser according to an embodiment of the present invention, FIG. 2 is a graph showing the relationship between the Pd value and the subcool amount with respect to changes in the refrigerant charge amount, and FIG. 3 is the number of revolutions of the compressor. FIG. 4 is a graph showing the relationship between the subcool amount and FIG. 4 is a graph showing the relationship between the outside air temperature and the subcool amount. The parts common to those shown in FIGS. 10 and 11 are designated by the same reference numerals, and the description thereof will be partially omitted.

The condenser 30 shown in FIG. 1 has a main body condenser 31 and a supercooling condenser 32. The main body capacitor 31 is a small-sized and high-performance capacitor, which is a so-called multi-pass type multi-flow type, but the one shown in the figure has one partition plate 18 provided in the header pipe 11. The refrigerant flowing from the inlet pipe 16 into the header pipe 11 passes through the plurality of flat pipes 13 into the header pipe 12, and after U-turning, returns to the header pipe 11 and flows out from the outlet pipe 17. It is a so-called two-pass type configured.

On the other hand, the subcooling condenser 32 attached to the body condenser 31 extends the header pipes 11 and 12 of the main condenser 31 by a predetermined length, and the header pipes 11a and 12a are extended between the header pipes 11a and 12a. A plurality of flat tubes 13 are provided so as to communicate 12a and are integrated with the main body capacitor 31.

A liquid tank 20 is provided between the main body condenser 31 and the supercooling condenser 32. The liquid refrigerant from the main body condenser 31 is introduced into the liquid tank 20 by the outlet pipe 17, The take-out pipe 23 guides the liquid refrigerant in the liquid tank 20 to the header pipe 11 a of the supercooling condenser 32. A guide pipe 33 is connected to the header pipe 12a of the supercooling condenser 22, and an expansion valve 24 is connected to the other end of the guide pipe 33.

Next, the operation of the above embodiment will be described. During normal cooling operation, the high-temperature and high-pressure vaporized refrigerant discharged from the compressor is condensed by the main condenser 31 and becomes liquid refrigerant, which flows into the liquid tank 20 through the outlet pipe 17. It is stored. The liquid refrigerant stored in the liquid tank 20 is pushed by the pressure of the refrigerant flowing in one after another, and a part of the liquid refrigerant is guided to the supercooling condenser 32 through the refrigerant outlet pipe 23. Then, it is subcooled by the airflow passing through the subcooling condenser 22, a predetermined subcool is taken, and it is guided to the expansion valve 24.

Here, in the final pass of the main body condenser 31, even if the refrigerant is enclosed in such a small amount that it is finally condensed, at least when the liquid refrigerant is stored in the liquid tank 20, it is supercooled. Since the liquid refrigerant is constantly supplied to the condenser 22 and is supercooled, the expansion valve 24 can always be stably supplied with the subcooled liquid refrigerant. Therefore, even if the amount of the enclosed refrigerant is reduced to protect the global environment, if the liquid refrigerant is present in the liquid tank 20, the stability of the cycle is ensured even if the amount of the enclosed refrigerant changes. In addition, the heat exchange action with the air is stably performed in the evaporator as well, and the air with a stable temperature can be blown into the vehicle interior.

As a result of conducting an experiment to confirm whether or not a predetermined subcool is obtained, the following results are obtained. 1) First, the relationship between the amount of enclosed refrigerant and the subcool As shown in FIG. 2, when the amount of enclosed refrigerant is small and the amount of liquid refrigerant is not stored in the liquid tank 20, the conventional condenser (broken line) is used. 2) and the capacitor of the present embodiment (shown by the solid line) can take substantially the same degree of subcooling (zone a). However, it has been found that when the amount of the liquid refrigerant is such that the liquid refrigerant is stored in the liquid tank 20, there is a difference of about 5 degrees in the subcool between the condenser 30 of the present embodiment and the conventional type ((b). zone). Moreover, this difference continues until the liquid cooling medium is completely filled with the liquid cooling medium. After the liquid is full, both the capacitor of the present embodiment and the condenser of the main body can take a subcool, so that both are the same (zone c).

Therefore, in the case of the embodiment, when the amount of the enclosed refrigerant is appropriate to some extent, the state in which the predetermined subcool can be taken is continued for a relatively long period of time, and the cycle is maintained even when the amount of the enclosed refrigerant is changed. The stability of can be secured. The pressure (Pd value) of the refrigerant at the inlet of the condenser in this state is slightly higher in the present embodiment than in the conventional one.

Further, the cooling power in the evaporator makes it possible to supply a refrigerant having a certain dryness (dryness = 0) to the expansion valve by ensuring a stable subcool, and as a result, the air blown out in the evaporator is cooled. As shown in FIG. 3, the temperature can be lowered as compared with the conventional one, and the efficiency of the evaporator can be improved.

2) Relationship between Revolution Speed of Compressor and Subcool As shown in FIG. 4, in the conventional condenser (shown by a broken line), the amount of circulating refrigerant increases with an increase in the revolution speed of the compressor, and is generated in the condenser. The amount of liquid refrigerant also increases, and so does the subcool. As a result, depending on the heat load applied to the evaporator, the amount of superheat (superheat degree; heating the refrigerant vaporized by the evaporator to a temperature equal to or higher than the saturation temperature) is reduced, and the refrigerant is not completely vaporized and the state of the liquid refrigerant is reduced. It may return to the compressor at, and there is a risk of liquid compression in the compressor. On the other hand, in the condenser of the present embodiment (shown by the solid line), the liquid refrigerant is accumulated in the liquid tank 20 or the condenser 31 of the main body even if the amount of the circulating refrigerant increases as the rotation speed of the compressor increases, so that the supercooling is performed. Since only a predetermined liquid refrigerant always exists in the condenser 32, the subcool amount is constant regardless of the rotation speed of the compressor, and the expansion valve 24 is stably supplied with the subcooled liquid refrigerant. It will be.

3) Relationship between outside air temperature and subcool As shown in FIG. 5, when the outside air temperature rises, the heat load applied to the evaporator also increases. Therefore, in order to supply a large amount of refrigerant to the evaporator, the rotation speed of the compressor is increased. Will rise. Therefore, as in the case of 2) above, in the conventional condenser (shown by the broken line), the outside air temperature rises, that is, the circulating refrigerant amount increases, and the subcool also rises accordingly. However, even if the outside air temperature rises, that is, the amount of circulating refrigerant increases, the condenser of this embodiment (shown by the solid line) always has a predetermined liquid refrigerant in the subcooling condenser 32, so that the subcool amount is constant. Therefore, the expansion refrigerant 24 is stably supplied with the liquid refrigerant with the subcool removed.

Therefore, even if there is a slight heat received by the outlet pipe 17 or the like or some pressure loss, the refrigerant does not gasify in the subcooling condenser 32, a hunting state does not occur, and the evaporator is cooled. Performance is improved, and it is in a favorable state in terms of cycle stability and ensuring cold power.

4) Relationship between Passage Resistance and Subcooling The passage resistance of the subcooling condenser 32 is related to the number of rows of the flat tubes 13, but as shown in FIG. 6, the passage resistance is large when the number of rows is small. If too much, the passage resistance decreases. According to the experiment, the proper number of rows with a predetermined heat radiation amount or more is 4 to 5, but in the case of the supercooling condenser 32 of the present embodiment, a cut is made in the header pipes 11a and 12a. There is also an advantage that tuning can be performed to an appropriate number of columns.

5) Relationship between Disturbance and Subcool In an automobile air conditioner, an increase in the speed at which the vehicle travels, particularly the wind speed during acceleration, is a major cause of the disturbance that is applied to the condenser. In the capacitor 30 (shown by the solid line) of the present embodiment, the subcool has a relatively large constant value regardless of the speed of the passing wind. On the other hand, in the conventional condenser (shown by the broken line), the subcool amount fluctuates under the influence of the wind speed, and the cooling power of the evaporator also fluctuates.

As described above, in this embodiment, even if the condenser is downsized and the performance is improved, the subcool can maintain a predetermined value, and the evaporator has a predetermined cooling power even when the refrigerant charge amount changes. Therefore, stability is secured for the entire cycle.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the utility model registration claim. For example, the above embodiment is a two-pass type capacitor, but three or more passes may be used. Further, the position of the supercooling condenser 32 may be provided not only in the lower portion of the main body condenser 31 but also in the upper portion as shown in FIG. Further, as shown in FIG. 9, it may be formed in a shape that conforms to the shape of the vehicle frame 35, and may be directly attached to this. If further added, the liquid refrigerant in the subcooling condenser 32 provided below is added to the upper portion. The header pipe 12 of the main body condenser 31 may be inserted and introduced into the expansion valve 24.

[0036]

[Effect of device]

 As described above, according to the present invention, since the supercooling condenser is provided integrally with the multi-flow type body condenser, the condenser as a whole becomes compact and there is no problem even if it is installed in a normal automobile air conditioner. There is no. Also, since a liquid tank is connected between both capacitors, it is not necessary to take subcooling in the body condenser, and subcooling can be taken reliably in the subcooling condenser. Therefore, not only can the amount of refrigerant filled in the cycle be reduced, but even if the amount of this refrigerant is changed to some extent, if the liquid refrigerant is stored in the liquid tank, the subcool can be reliably removed, and the amount of refrigerant filled can be reduced. The cycle operates stably even with changes, and the cooling performance of the evaporator also improves.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a capacitor according to an embodiment of the present invention,

FIG. 2 is a graph showing the relationship between the Pd value and the subcool amount with respect to changes in the refrigerant charge amount,

FIG. 3 is a graph showing the performance of a capacitor,

FIG. 4 is a graph showing the relationship between the number of revolutions of the compressor and the amount of subcool,

FIG. 5 is a graph showing the relationship between outside air temperature and subcool amount.

FIG. 6 is a graph showing the relationship between the number of rows of flat tubes and the amount of heat radiation,

FIG. 7 is a graph showing the relationship between the wind speed passing through the condenser and the subcool,

FIG. 8 is a schematic sectional view of a capacitor according to another embodiment of the present invention,

FIG. 9 is a schematic sectional view of a capacitor according to still another embodiment of the present invention,

FIG. 10 is a perspective view showing a conventional capacitor,

11 is a cross-sectional view of FIG.

[Explanation of symbols]

11, 12 ... Header pipe, 11a, 12a
... extension header pipe, 13 ... flat pipe,
14 ... core part, 16 ... inlet pipe,
17 ... Guide pipe (outlet pipe), 18 ... Partition plate,
20 ... Liquid tank, 23 ... Guide pipe (refrigerant take-out pipe), 31 ... Main body condenser, 32 ...
Supercooling condenser, 33 ... Guide tube, f ... Heat transfer fin.

Claims (1)

[Scope of utility model registration request] 1. A core part (14) by providing header pipes (11, 12) at both ends of a large number of flat tubes (13) arranged in parallel with heat transfer fins (f) interposed therebetween. By forming a partition plate (18) in each of the header portions (11, 12), the fluid to be heat-exchanged from the inlet pipe (16) reaches the outlet pipe (17) to the core portion (14). ) A multi-pass type multi-flow type main body capacitor that meanders through the inside (31)
This main body condenser (31) has a header pipe (11,1
2) Extension header pipe (11
a, 12a) also has a plurality of flat tubes (13) to form a supercooling condenser (32) integrally with the body condenser (31), and the outlet side header pipe (31) of the body condenser (31) 11 or 12) is connected to the end of the guide tube (17), which is connected to the inlet of the liquid tank (20) and one of the header pipes (11a or 12a) of the supercooling condenser (32). Install the end of the guide tube (23) so that the liquid tank (20)
A condenser for an air conditioner for automobiles, which is installed at each outlet.