JP2008030700A - Vehicular air conditioning system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular air conditioning system reduced in the amount of refrigerant filled in the system, improved in installability on a vehicle, and reduced in costs by eliminating a receiver. <P>SOLUTION: In this vehicular air conditioning system 1, a compressor 2 for compressing refrigerant, a condenser 3 for liquefying the refrigerant flowing from the compressor 2 by condensing, a pressure reducing means 7 for reducing the pressure of the refrigerant sent from the condenser 3 and an evaporator 8 for evaporating the refrigerant supplied from the pressure reducing means 7 are connected in this order by a refrigerant pipe 9 to structure a refrigerant circuit 10, and the refrigerant circuit 10 is filled with a predetermined quantity of the refrigerant. A heat exchanger tube 3C arranged in a lower part of the condenser 3 works as a reservoir part 3F for the condensed refrigerant, and a certain quantity of the refrigerant having condensate depression of 5-10°C stored in the reservoir part 3F is filled in the refrigerant circuit 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a receiver-less air conditioning system for a vehicle that is used for in-vehicle air conditioning of an automobile or the like.

  In general, an air conditioning system for a vehicle stores a compressor that compresses a refrigerant, a condenser that condenses and liquefies the refrigerant flowing from the compressor, and stores the refrigerant condensed by the condenser, and separates the gas component to obtain only the liquid refrigerant. A refrigerant circuit is configured by connecting a receiver to be sent out, a decompression unit that adiabatically expands the liquid refrigerant supplied from the receiver, and an evaporator that evaporates the refrigerant supplied from the decompression unit in this order. The refrigerant circuit of such an air conditioning system for a vehicle cannot be a completely sealed refrigerant circuit that is welded like a stationary air conditioner because it is mounted on a vehicle. Used to connect each device and the refrigerant pipe. Further, many compressors usually use a traveling engine of a vehicle as a drive source, and an open type compressor having a drive shaft protruding outside is used.

From the above, in the air conditioning system for vehicles, even under the present situation where the quality of each device constituting the refrigerant circuit is extremely high, minute leakage of the refrigerant filled in the refrigerant circuit is essentially inevitable. The refrigerant circuit is generally filled with an excessive amount of refrigerant in consideration of minute leakage of the refrigerant. For this reason, it is indispensable to install a receiver that stores an extra refrigerant in the refrigerant circuit.
Therefore, conventionally, as shown in FIG. 3, a receiver-integrated capacitor in which a receiver 02 incorporating a dryer and a strainer is integrally assembled on the side of the capacitor 01 is often used. In addition, there has been proposed an apparatus in which a condenser and a receiver are integrated and a dryer in which a desiccant and a strainer are incorporated in a refrigerant pipe on the downstream side (see Patent Document 1).

JP-A-7-243720

  However, in the above, a process for assembling the receiver integrally with the capacitor is necessary, and this is a cost increase factor. In addition, since the receiver is integrally assembled to the side of the capacitor 01, the heat radiation area of the capacitor is reduced by an amount corresponding to the occupied area of the receiver. As a result, mountability on the vehicle is impaired. Further, since the receiver is assembled, a weight imbalance is generated in the capacitor and the capacitor is easily affected by vibrations. Therefore, there is a problem that measures such as an increase in strength are required.

  The present invention has been made in view of such circumstances, and by reducing the amount of refrigerant in the system, it is possible to reduce the amount of refrigerant charged in the system, and to improve the mounting property in a vehicle and reduce the cost. An object of the present invention is to provide a vehicle air-conditioning system capable of performing the above.

In order to solve the above problems, the vehicle air conditioning system of the present invention employs the following means.
That is, an air conditioning system for a vehicle according to the present invention includes a compressor that compresses a refrigerant, a condenser that condenses and liquefies the refrigerant flowing from the compressor, a decompression unit that decompresses the refrigerant sent from the condenser, and the decompression An evaporator for evaporating the refrigerant supplied from the means is connected in this order through a refrigerant pipe to form a refrigerant circuit, and in the vehicle air conditioning system in which a predetermined amount of refrigerant is filled in the refrigerant circuit, The heat exchange tube disposed in the section is used as a liquid reservoir for condensed refrigerant, and the refrigerant circuit is filled with an amount of refrigerant that causes the degree of supercooling of the refrigerant stored in the liquid reservoir to be 5 to 10 ° C. It is characterized by being.

  According to the present invention, the heat exchange tube disposed in the lower part of the condenser is used as a liquid reservoir for condensed refrigerant, and the amount of supercooling of the refrigerant stored in the liquid reservoir is 5 to 10 ° C. Since the refrigerant is filled in the refrigerant circuit, the capacitor can be provided with two functions of liquid storage and gas-liquid separation in addition to the original refrigerant condensing function. This makes it possible to eliminate the receiver that was responsible for the two functions of liquid reservoir and gas-liquid separation, and eliminates the receiver that has been integrated into the side of the conventional capacitor and eliminates the need for a vehicle air conditioning system. Can be realized. In a system with a receiver, the receiver performs a gas-liquid separation function and can supply only the liquid refrigerant to the expansion valve. Therefore, the degree of supercooling may be 0 ° C. There is a concern that the expansion valve may cause hunting and the blowing temperature may be affected. In the present invention, by setting the degree of supercooling to 5 to 10 ° C. in the liquid reservoir of the condenser, only the liquid refrigerant can be supplied to the expansion valve even if the receiver is not used. In addition, by eliminating the need for a receiver, the effective area of the capacitor can be expanded, and the liquid reservoir can be covered by that amount. Can be improved. Further, since the amount of refrigerant charged in the refrigerant circuit can be reduced by the amount corresponding to the refrigerant stored in the receiver, effective use of resources can be achieved. Furthermore, since the weight balance of the capacitor is improved, vibration countermeasures can be simplified, and the cost of the system can be significantly reduced in combination with the abolition of the receiver and the reduction of the refrigerant charging amount.

  Furthermore, the vehicle air conditioning system of the present invention is characterized in that, in the above vehicle air conditioning system, the degree of supercooling of the refrigerant is 7 to 8 ° C.

  According to the present invention, since the degree of supercooling of the refrigerant is 7 to 8 ° C., the amount of liquid refrigerant corresponding to the degree of supercooling of 7 to 8 ° C. is stored in the condenser. This means that in a vehicular air conditioning system in which minute leakage of refrigerant is essentially unavoidable, a sufficient amount of refrigerant is still charged even when the minute leakage is taken into consideration. In addition, even if the receiver is not used, the supercooling degree that is optimal as a system balance can be achieved without causing the gas-liquid two-phase refrigerant to flow into the expansion valve. Therefore, the air conditioning performance equivalent to a system with a receiver can be exhibited despite the receiverlessness.

  Furthermore, in the vehicle air conditioning system according to the present invention, in any one of the above-described vehicle air conditioning systems, a dryer filled with a desiccant is connected to the refrigerant pipe between the condenser and the pressure reducing unit. It is characterized by.

  According to the present invention, since the dryer filled with the desiccant is connected to the refrigerant line between the condenser and the pressure reducing means, the moisture in the refrigerant circuit by the dryer can be used even in a receiverless system. The removal function can be maintained.

  Furthermore, the vehicle air conditioning system of the present invention is characterized in that in the vehicle air conditioning system, a strainer is built in the dryer.

  According to the present invention, since the strainer is built in the dryer, it is possible to maintain the function of removing the foreign matter in the refrigerant circuit by the strainer even in a receiverless system, and the strainer is effectively used to hold the desiccant. can do.

  According to the present invention, in addition to the original refrigerant condensing function, the condenser can be provided with two functions of liquid reservoir and gas-liquid separation, and therefore the receiver that has been responsible for the two functions of liquid reservoir and gas-liquid separation. Can be abolished. As a result, the effective area of the capacitor can be expanded, and the liquid reservoir can be covered by that amount, so that the size of the capacitor does not increase compared to the conventional receiver-integrated capacitor, and the mountability to the vehicle can be improved. it can. In addition, the amount of refrigerant charged in the system can be reduced by an amount corresponding to the refrigerant stored in the receiver, thereby effectively using resources. Furthermore, the cost of the system can be greatly reduced by abolishing the receiver and reducing the refrigerant charge amount.

Embodiments according to the present invention will be described below with reference to the drawings.
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 shows a configuration diagram of a vehicle air conditioning system 1 according to the present embodiment. The vehicle air conditioning system 1 includes a compressor 2, a condenser 3, a dryer 4, a pressure switch 5, a decompression means 7, and an evaporator 8, and these devices are arranged in this order via a refrigerant pipe 9. The refrigerant circuit 10 is comprised by connecting.

The compressor 2 is installed in the engine room of the vehicle, and is driven by receiving power from a vehicle travel engine (not shown) to suck in and compress the low-temperature and low-pressure refrigerant gas evaporated by the evaporator 8. However, it is discharged as a high-temperature and high-pressure refrigerant gas.
The condenser 3 dissipates the refrigerant flowing in from the compressor 2 by heat exchange with the outside air to be condensed and liquefied. The capacitor 3 is of a type called a parallel flow capacitor, and a pair of left and right headers 3A and 3B, and a number of flat heat exchange tubes arranged in parallel at a predetermined interval between the headers 3A and 3B. 3C and fins (not shown) provided between a large number of heat exchange tubes 3C, and are generally installed via a mounting bracket 3D in a place where the traveling wind is easily received in the engine room of the vehicle.

  The condenser 3 is provided with a refrigerant inlet 3E in one header 3B. The refrigerant flows in from the refrigerant inlet 3E, and the plurality of heat exchange tubes 3C are parallel to the other header 3A. The flow is folded at the header 3A, and is again distributed to the header 3B through the plurality of heat exchange tubes 3C. While repeating such meandering, the refrigerant is condensed and stored in a plurality of heat exchange tubes 3 </ b> C disposed below the condenser 3. The plurality of heat exchange tubes 3 </ b> C disposed in the lower part of the condenser 3 constitute a liquid reservoir 3 </ b> F for storing the refrigerant condensed and liquefied by the condenser 3. The refrigerant stored in the liquid reservoir 3F is sent to the dryer 4 through the refrigerant pipe 9 from the refrigerant outlet 3G provided in the header 3B.

FIG. 2 shows the configuration of the dryer 4. The dryer 4 is connected to the refrigerant pipe 9 for removing moisture and foreign matters mixed in the refrigerant circuit 10, and a throttle portion to which the refrigerant pipe 9 is connected is formed at both ends. It comprises a cylindrical dryer body 4A, a strainer 4B fixedly installed at two locations on both ends of the dryer body 4A by rolling, and a desiccant 4C filled between the strainers 4B.
A pressure switch 5 that detects a high pressure in the refrigerant circuit 10 is provided on the downstream side of the dryer 4.

A pressure reducing means 7 is provided on the downstream side of the pressure switch 5. The decompression means 7 is constituted by an expansion valve, and adiabaticly expands the high-pressure liquid refrigerant liquefied by the capacitor 3 and flows it into the evaporator 8 as a low-pressure low-temperature gas-liquid two-phase refrigerant.
The evaporator 8 is arranged on the cabin side of the vehicle so that outside air or air in the cabin is circulated by a blower (not shown). In the evaporator 8, heat is exchanged between the refrigerant and outside air or cabin air, and the refrigerant absorbs heat from the air and evaporates, while the air is cooled and blown out into the cabin. Thereby, air conditioning in the cabin is performed. The refrigerant evaporated by the evaporator 8 is sucked into the compressor 1 again.

  Further, in the refrigerant circuit 10 configured as described above, the degree of supercooling of the refrigerant stored in the liquid reservoir 3F formed below the capacitor 3 is 5 to 10 ° C., preferably 7 to 8 ° C. The amount of refrigerant is filled. Here, R134a which is an HFC refrigerant not containing chlorine is used.

Next, the operation of the vehicle air conditioning system 1 according to the present embodiment will be described.
The refrigerant filled in the refrigerant circuit 10 is compressed when the compressor 2 is driven and is sent to the capacitor 3. The refrigerant heat-exchanged with the outside air in the condenser 3 is condensed and liquefied and stored in a liquid reservoir 3F formed in the lower part thereof. Here, the refrigerant is given a degree of supercooling of 5 to 10 ° C, preferably 7 to 8 ° C. If the degree of supercooling is 7 to 8 ° C., this corresponds to a refrigerant amount of about 40 g. This refrigerant has a sufficient amount of refrigerant against the above-described minute leakage of the refrigerant.

  In a normal system with a receiver, the receiver performs a gas-liquid separation function and can supply only liquid refrigerant to the expansion valve. Therefore, the degree of supercooling may be basically 0 ° C. However, if the receiver is simply changed, the gas-liquid two-phase refrigerant flows into the expansion valve, and the expansion valve may cause hunting, which may affect the blowing temperature. In the present embodiment, since the degree of supercooling of 5 to 10 ° C. is given by the liquid reservoir 3F of the condenser 3, only the liquid refrigerant can be supplied to the expansion valve even if the receiver is not used.

The refrigerant that has been supercooled as described above in the liquid reservoir 3F and separated into gas components flows into the dryer 4 through the refrigerant pipe 9, where foreign substances and moisture are mixed in the refrigerant circuit 10. If removed, it is removed by the strainer 4B and the desiccant 4C. Thereafter, the refrigerant reaches the decompression means 7 via the pressure switch 5, where it is adiabatically expanded to form a low-temperature and low-pressure gas-liquid two-phase refrigerant and flows into the evaporator 8.
The refrigerant that has flowed into the evaporator 8 exchanges heat with the outside air or the cabin air that is blown to the evaporator 8 to cool the air. On the other hand, the refrigerant evaporated by heat exchange with air is sucked into the compressor 2 again, and the same operation is repeated thereafter. Thereby, air conditioning in the cabin can be performed.

Thus, according to the present embodiment, the following effects can be obtained.
A liquid reservoir 3F is formed in the lower part of the condenser 3, where the refrigerant condensed and liquefied by the condenser 3 is stored to give a supercooling degree of 5 to 10 ° C, preferably 7 to 8 ° C. Thus, the capacitor 3 can be provided with the two functions of the refrigerant liquid reservoir and the gas-liquid separation that were conventionally performed by the receiver. Thereby, a receiver can be abolished and the vehicle air conditioning system 1 without a receiver can be realized.

In addition, even if it is made receiverless, only liquid refrigerant can be reliably supplied to the expansion valve, so there is no concern that the expansion valve will cause hunting and affect the blowing temperature, and air conditioning performance equivalent to that of a system with a receiver can be obtained. it can.
In addition, since the effective area of the capacitor 3 can be increased by eliminating the receiver, the liquid storage portion 3F can be sufficiently covered by that portion, and the capacitor 3 is not increased in size as compared with the conventional receiver-integrated capacitor. Can be improved.

Further, by eliminating the receiver, the amount of refrigerant charged in the refrigerant circuit 10 can be reduced by the amount corresponding to the refrigerant stored in the receiver. For this reason, effective use of resources can be achieved. Moreover, since the weight balance of the capacitor 3 itself can be improved by eliminating the receiver, vibration countermeasures and the like can be simplified.
Furthermore, the cost of the vehicle air-conditioning system 1 can be significantly reduced by abolishing the receiver, reducing the refrigerant charging amount, simplifying the vibration countermeasures of the capacitor 3, and the like.

  Further, in response to the receiver-less operation, the dryer 4 incorporating the strainer 4B and the desiccant 4C is connected to the refrigerant pipe 9 between the condenser 3 and the decompression means 7, so that foreign matters in the refrigerant circuit 10 are removed. The function and the water removal function can be maintained as they are.

In the above embodiment, an example in which a parallel flow type capacitor is used as the capacitor 3 has been described. However, the present invention is not limited to this, and other capacitors such as a fin tube type or a serpentine type may be used. The present invention can be similarly applied to a device using a capacitor.
Further, the compressor is not limited to an open type compressor, and can be similarly applied to a vehicle air conditioning system in which a hermetic type compressor is used.

1 is a schematic configuration diagram of a vehicle air conditioning system according to an embodiment of the present invention. It is sectional drawing of the dryer used for the vehicle air conditioning system shown in FIG. It is a perspective view of the receiver integrated capacitor used for the conventional vehicle air-conditioning system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle air-conditioning system 2 Compressor 3 Condenser 3C Heat exchange tube 3F Liquid reservoir 4 Dryer 7 Pressure reducing means 8 Evaporator 9 Refrigerant line 10 Refrigerant circuit

Claims (4)

A compressor that compresses the refrigerant; a condenser that condenses and liquefies the refrigerant flowing from the compressor; a decompression unit that decompresses the refrigerant sent from the capacitor; and an evaporator that evaporates the refrigerant supplied from the decompression unit. In the vehicle air conditioning system in which the refrigerant circuit is configured by being connected by the refrigerant pipe in this order, and the refrigerant circuit is filled with a predetermined amount of refrigerant,
The heat exchange tube disposed in the lower part of the condenser is a condensing refrigerant reservoir,
An air conditioning system for vehicles, wherein the refrigerant circuit is filled with an amount of refrigerant that causes the degree of supercooling of the refrigerant stored in the liquid reservoir to be 5 to 10 ° C.   The vehicle air conditioning system according to claim 1, wherein the degree of supercooling of the refrigerant is 7 to 8 ° C.   The vehicular air conditioning system according to claim 1 or 2, wherein a dryer filled with a desiccant is connected to a refrigerant pipe between the condenser and the pressure reducing means. The vehicle air conditioning system according to claim 3, wherein a strainer is built in the dryer.

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