JP2013204905A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the refrigerant flow rate of a heat exchanger with a receiver tank functioning as an evaporator.SOLUTION: A vertical flow type heat exchanger 5 for use outside a cabin includes a pair of upper and lower header tanks 54, 55 and a plurality of tubes 56 communicating them with each other. The plurality of tubes 56 are grouped into a refrigerator condensation portion 51 and a sub-cool portion 53. A receiver tank 52 is fixed to the lower header tank 55. A seventh refrigerant pipe 28 communicates the second chamber 55b of the lower header tank 55 with the receiver tank 52. A seventh refrigerant pipe 29 communicates the third chamber 55c of the lower header tank 55 with the receiver tank 52. The refrigerant condensation portion 51 has a larger flow passage sectional area than the sub-cool portion 53. In the bottom portion of the receiver tank 52, a through hole 76 connected to the opening end of the seventh refrigerant pipe 28 and a through hole 77 connected to the opening end of an eighth refrigerant pipe 29 are formed. A straightner 78 is inserted into the through hole 77.

Description

  The present invention includes a pair of upper and lower header tanks extending in parallel to each other and a plurality of tubes communicating with the pair of header tanks, and a so-called longitudinal flow type in which refrigerant flows in the vertical direction in the plurality of tubes. Relates to heat exchangers.

  Patent document 1 is disclosing the longitudinal flow type heat exchanger which comprises the vehicle air conditioner. The heat exchanger includes a pair of upper and lower header tanks extending in parallel to each other, a plurality of tubes communicating with the pair of header tanks, and a plurality of tubes provided in each header tank. And a sub-capacitor section).

  In Patent Document 1, a receiver tank (liquid tank) is connected and fixed to a lower header tank. The receiver tank is formed with first and second refrigerant passages at the bottom thereof. The first refrigerant passage communicates a portion of the lower header tank that communicates with the capacitor portion and the receiver tank. The second refrigerant passage communicates a portion of the lower header tank that communicates with the sub capacitor portion and the receiver tank.

  In patent document 1, the refrigerant | coolant transfer pipe | tube is provided in the receiver tank. The refrigerant transfer pipe extends in the vertical direction, the lower end opening thereof is connected to the first refrigerant passage, and the upper end opening is located in the upper part in the receiver tank.

  In patent document 1, the refrigerant | coolant condensed in the capacitor | condenser part is sent to the upper part in a receiver tank through a 1st refrigerant path and a refrigerant transfer pipe. In addition, the refrigerant in the receiver tank flows into the sub condenser part through the second refrigerant passage, and the refrigerant is supercooled in the sub condenser part.

JP-A-9-170854

However, in the heat exchanger with a receiver tank as described above, a refrigerant transfer pipe is provided in the receiver tank.
For this reason, in order to use the heat exchanger with a receiver tank as described above as an evaporator constituting the heat pump type vehicle air conditioner, the refrigerant flow direction in the heat exchanger is reversed (that is, the refrigerant flows backward). When the liquid refrigerant is evaporated in the sub-capacitor part and the condenser part, the liquid refrigerant is supplied from the receiver tank to the condenser part when the liquid refrigerant level in the receiver tank falls below the height of the refrigerant transfer pipe. As a result, the refrigerant flow rate at the condenser may become unstable.

  This invention makes it a subject to stabilize the refrigerant | coolant flow rate of the heat exchanger with a receiver tank which can function as an evaporator in view of such an actual condition.

  Therefore, the heat exchanger according to the present invention includes a pair of upper and lower header tanks extending in parallel to each other, a plurality of tubes communicating with the pair of header tanks, and a plurality of tubes provided in each header tank. A separator that is divided into two tube groups each including a second tube group, a receiver tank that is erected in parallel with the plurality of tubes, and a portion that communicates with the first tube group in the lower header tank; A first communication pipe that communicates with the receiver tank, and a second communication pipe that communicates the receiver tank with a portion of the lower header tank that communicates with the second tube group. The receiver tank includes a first refrigerant flow port connected to the open end of the first communication pipe and a second refrigerant flow port connected to the open end of the second communication pipe at the bottom thereof. When the heat exchanger according to the present invention functions as a condenser, the refrigerant passes through the first communication pipe, the receiver tank, and the second communication pipe from the first tube group to the second tube group. , The refrigerant is condensed in the first tube group, and the refrigerant is supercooled in the second tube group. When the heat exchanger according to the present invention functions as an evaporator, the refrigerant passes through the second communication pipe, the receiver tank, and the first communication pipe from the second tube group to the first tube group. The refrigerant evaporates in the first and second tube groups.

  According to the present invention, the receiver tank has a first refrigerant flow port connected to the open end of the first communication pipe and a second refrigerant flow port connected to the open end of the second communication pipe at the bottom of the receiver tank. And comprising. Thereby, when the heat exchanger functions as an evaporator, the refrigerant from the second tube group flows into the receiver tank through the second communication pipe and the second refrigerant circulation port, Since the refrigerant flows through the first refrigerant flow port and the first communication pipe to the first tube group, the refrigerant can circulate relatively smoothly in the receiver tank, and thus the refrigerant flow rate can be stabilized. .

The figure which shows the heat pump circuit at the time of vehicle interior cooling in one Embodiment of this invention The figure which shows the heat pump circuit at the time of vehicle interior heating in embodiment same as the above The perspective view of a vehicle exterior heat exchanger, and the elements on larger scale which show the structure between tubes The figure which shows schematic structure of a vehicle exterior heat exchanger, and the flow of an internal refrigerant | coolant The figure which shows the relationship between the temperature fall amount of the refrigerant | coolant in a vehicle exterior heat exchanger, and a subcool occupancy Diagram showing schematic configuration of receiver tank The figure which shows the modification of the flow volume adjustment part of the refrigerant | coolant provided in the bottom part of a receiver tank.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 and 2 show an outline of a heat pump circuit according to an embodiment of the present invention. In the present embodiment, the heat exchanger according to the present invention will be described taking the heat pump circuit of the vehicle air conditioner as an example, but the heat pump circuit to which the heat exchanger according to the present invention is applied is not limited thereto.

  FIG. 1 shows a heat pump circuit during vehicle interior cooling. FIG. 2 shows a heat pump circuit during vehicle interior heating.

  The heat pump circuit of the vehicle air conditioner 1 includes a compressor 2, a vehicle interior condenser 4 disposed on the downstream side of the air passage 3 in the vehicle interior, a vehicle exterior heat exchanger 5 disposed outside the vehicle interior, And a vehicle interior evaporator 6 disposed on the upstream side of the air passage 3 in the vehicle interior. Here, the exterior heat exchanger 5 corresponds to the heat exchanger according to the present invention.

  The vehicle exterior heat exchanger 5 includes a refrigerant condensing unit 51 that condenses and liquefies a gas refrigerant when it functions as a condenser, a receiver tank 52 that can store liquid refrigerant from the refrigerant condensing unit 51, and a receiver tank 52. The subcool part 53 which supercools the liquid refrigerant of this is comprised, The detail is mentioned later using FIGS. 3-7.

  A fan 7 is disposed at the upstream end of the air passage 3, and a damper 8 that opens and closes the air vent is attached to the air vent of the vehicle interior condenser 4.

The first refrigerant pipe 9 extends from the refrigerant discharge port of the compressor 2 through the vehicle interior condenser 4 to the refrigerant condensing part 51 of the vehicle exterior heat exchanger 5. A first on-off valve 10 is interposed in the middle of the first refrigerant pipe 9.
The second refrigerant pipe 11 branches from the first refrigerant pipe 9 between the first on-off valve 10 and the refrigerant condensing part 51 of the vehicle exterior heat exchanger 5 and reaches the refrigerant intake port of the compressor 2. A second on-off valve 12 and an accumulator 13 are interposed in the middle of the second refrigerant pipe 11.

The third refrigerant pipe 14 extends from the subcool portion 53 of the vehicle exterior heat exchanger 5 to the vehicle interior evaporator 6. A third on-off valve 15, a first check valve 16, a high temperature portion 17 </ b> A of the internal heat exchanger 17, and a first expansion valve 18 are interposed in the middle of the third refrigerant pipe 14.
The fourth refrigerant pipe 19 is connected to the second refrigerant pipe 11 from the vehicle interior evaporator 6 between the second on-off valve 12 and the accumulator 13. In the middle of the fourth refrigerant pipe 19, a fourth open / close valve 20 and a low temperature part 17B of the internal heat exchanger 17 are interposed. In the internal heat exchanger 17, heat exchange is performed between the refrigerant flowing through the high temperature portion 17A and the refrigerant flowing through the low temperature portion 17B.

The fifth refrigerant pipe 21 branches on the upstream side of the first on-off valve 10 of the first refrigerant pipe 9 and reaches between the subcool portion 53 of the vehicle exterior heat exchanger 5 and the third on-off valve 15 to form a third refrigerant pipe. 14. A second expansion valve 23 and a second check valve 24 are interposed in the middle of the fifth refrigerant pipe 21. Here, when the first on-off valve 10 is open, the second expansion valve 23 is substantially closed because the passage resistance is larger than that of the first on-off valve 10, but may be forcibly closed. Therefore, the second expansion valve 23 and the first on-off valve 10 are selectively opened.
The sixth refrigerant pipe 25 branches on the upstream side of the first on-off valve 10 of the first refrigerant pipe 9 and reaches between the first check valve 16 and the high temperature portion 17A of the internal heat exchanger 17 to form the third refrigerant pipe. 14. A fifth on-off valve 27 is interposed in the middle of the sixth refrigerant pipe 25.

  Next, the outline | summary at the time of air_conditionaing | cooling operation of the vehicle air conditioner 1 and heating operation is demonstrated.

  When the vehicle interior is cooled, as shown in FIG. 1, the first on-off valve 10, the third on-off valve 15, and the fourth on-off valve 20 are opened, and the damper 8, the second on-off valve 12, the second expansion valve 23, and the second on-off valve 5 The on-off valve 27 is closed.

  The high-temperature and high-pressure gas refrigerant pressurized by the compressor 2 circulates through the vehicle interior condenser 4, but the damper 8 is closed and air flow to the vehicle interior condenser 4 is blocked, so Heat exchange (cooling) is hardly performed, and the refrigerant flows out in a high-temperature and high-pressure gas state, and flows into the refrigerant condensing unit 51 of the vehicle exterior heat exchanger 5 through the first on-off valve 10.

  The exterior heat exchanger 5 functions as a condenser, and the refrigerant condensing unit 51 exchanges heat with the outside air (radiates heat) to condense and liquefy the gas refrigerant. This liquid refrigerant is supercooled in the subcool section 53 via the receiver tank 52. The supercooled liquid refrigerant reaches the first expansion valve 18 through the third opening / closing valve 15, the first check valve 16, and the high temperature portion 17A of the internal heat exchanger 17, and is decompressed by the first expansion valve 18. The liquid is mixed and flows into the vehicle interior evaporator 6. In the vehicle interior evaporator 6, the refrigerant is gasified (vaporized) through heat exchange (heat absorption) with vehicle interior air blown from the fan 7. The vehicle interior air cooled by this heat exchange is blown into the vehicle interior to cool the vehicle interior. The refrigerant gasified in the vehicle interior evaporator 6 returns to the suction port of the compressor 2 through the fourth on-off valve 20, the low temperature portion 17 </ b> B of the internal heat exchanger 17, and the accumulator 13. In this way, the heat pump cycle at the time of cooling the passenger compartment is repeated.

  When the vehicle interior is dehumidifying and cooling, the damper 8 is simply opened in the state of the above-described vehicle interior cooling. Thereby, the vehicle interior air cooled and condensed by the vehicle interior evaporator 6 and reduced in moisture can be reheated by the downstream vehicle interior condenser 4 to blow air having a low relative humidity into the vehicle interior. In order to further enhance the cooling / dehumidifying function of the vehicle interior evaporator 6, the fifth on-off valve 27 provided in the sixth refrigerant pipe 25 is opened to increase the flow rate of the refrigerant supplied to the vehicle interior evaporator 6. May be.

  On the other hand, at the time of vehicle interior heating, as shown in FIG. 2, the first on-off valve 10, the third on-off valve 15, the fourth on-off valve 20, and the fifth on-off valve 27 are closed, and the damper 8 and the second on-off valve 12 are closed. And the 2nd expansion valve 23 is opened.

  The high-temperature and high-pressure gas refrigerant pressurized by the compressor 2 flows into the vehicle interior condenser 4 and is heat-exchanged (radiated) with the vehicle interior air blown from the fan 7 to be condensed and liquefied. The vehicle interior air is heated by this heat exchange. The heated vehicle interior air is blown into the vehicle interior to heat the vehicle interior.

  The liquid refrigerant condensed and liquefied in the vehicle interior condenser 4 is decompressed through the second expansion valve 23 to be in a gas-liquid mixed state, and is passed through the second check valve 24 to the subcool portion 53 of the vehicle exterior heat exchanger 5. Inflow.

  The exterior heat exchanger 5 functions as an evaporator, and the subcool portion 53 and the refrigerant condensing unit 51 exchange heat (absorb heat) with the outside air to gasify the refrigerant. This gas refrigerant returns to the suction port of the compressor 2 through the second on-off valve 12 and the accumulator 13. In this way, the heat pump cycle at the time of cooling the passenger compartment is repeated.

  When the vehicle interior is dehumidified and heated, for example, the fourth on-off valve 20 interposed in the fourth refrigerant pipe 19 and the fifth on-off valve 27 interposed in the sixth refrigerant pipe 25 are opened, thereby The evaporator 6 condenses moisture in the passenger compartment air and lowers the relative humidity of the air.

  Accordingly, the vehicle exterior heat exchanger 5 functions as a condenser during vehicle interior cooling and dehumidification (dehumidification cooling), and functions as an evaporator during vehicle interior heating and dehumidification (dehumidification heating).

Next, the configuration of the exterior heat exchanger 5 will be described with reference to FIGS. 3 and 4.
FIG. 3A is a perspective view of the vehicle exterior heat exchanger 5. FIG.3 (b) is the elements on larger scale of the part A of Fig.3 (a). FIG. 4 shows a schematic configuration of the vehicle exterior heat exchanger 5 and a refrigerant flow in the vehicle exterior heat exchanger 5. In particular, FIG. 4A shows the flow of refrigerant when the vehicle exterior heat exchanger 5 functions as a condenser, and FIG. 4B shows the vehicle exterior heat exchanger 5 functions as an evaporator. It shows the flow of the refrigerant when.

The vehicle exterior heat exchanger 5 includes a pair of upper and lower header tanks 54 and 55 extending in parallel to each other, a plurality of tubes 56 arranged in a row communicating with the pair of header tanks 54 and 55, and between the tubes 56 and 56. And the corrugated fins 57 provided in the.
In the present embodiment, the extending direction of the header tanks 54 and 55 is defined as the width direction (left-right direction) of the vehicle exterior heat exchanger 5, and the front, rear, left and right of the vehicle exterior heat exchanger 5 are defined. And outside air can distribute | circulate in the front-back direction of the vehicle exterior heat exchanger 5. As shown in FIG.

The tubes 56 are aluminum tubes having a flat cross section, and are arranged with the flat surfaces facing each other at intervals in the extending direction of the header tanks 54 and 55.
The corrugated fins 57 are arranged by being joined between the flat surfaces of the tubes 56 by brazing. Instead of the corrugated fins 57, a large number of flat plate fins that penetrate the respective tubes 56 may be arranged in the vertical direction.

As shown in FIG. 4, the plurality of tubes 56 are grouped into four paths including first to fourth paths 101 to 104 in order from the left side to the right side of the vehicle exterior heat exchanger 5.
Assuming that the number of tubes in each of the first to fourth paths 101 to 104 is N1 to N4, N1 to N4 satisfy the relationship of the following expression (1).

    N1 ≧ N2 ≧ N3 ≧ N4 (1)

  Here, although an example of the combination of N1-N4 is shown in the following formula | equation (2), the combination of N1-N4 is not restricted to this.

    (N1, N2, N3, N4) = (40, 28, 26, 15) (2)

The upper header tank 54 is a cylindrical body made of aluminum, and includes two separators 61 and 62 therein, and both ends are closed by lid members.
The separator 61 is located immediately above the boundary between the first path 101 and the second path 102, and partitions the two.
The separator 62 is located immediately above the boundary between the third path 103 and the fourth path 104, and partitions the two.

  Therefore, the internal space of the upper header tank 54 is partitioned by the first chamber 54a partitioned by the lid member and the separator 61, the second chamber 54b partitioned by the separators 61 and 62, and the separator 62 and the lid member. The third chamber 54c is divided into three.

The first chamber 54a of the upper header tank 54 communicates with the first refrigerant pipe 9 through a previously formed refrigerant circulation hole 9a.
The third chamber 54c of the upper header tank 54 communicates with the third refrigerant pipe 14 through a previously formed refrigerant circulation hole 14a. Here, the third refrigerant pipe 14 corresponds to the “refrigerant circulation pipe” of the present invention, and is connected to the upper header tank 54 so that the refrigerant flows therethrough. The flow path cross-sectional area of the third refrigerant pipe 14 is equal to or less than the total flow path cross-sectional area of the fourth path 104 (S4 described later).

The lower header tank 55 is a cylindrical body made of aluminum, and has two separators 63 and 64 therein, and both ends are closed by lid members.
The separator 63 is located immediately below the boundary between the second path 102 and the third path 103, and partitions the two.
The separator 64 is located immediately below the boundary between the third path 103 and the fourth path 104, and partitions the two.

  Accordingly, the internal space of the lower header tank 55 is defined by the first chamber 55a defined by the lid member and the separator 63, the second chamber 55b defined by the separators 63 and 64, and the separator 64 and the lid member. The third chamber 55c is divided into three sections.

The second chamber 55b of the lower header tank 55 communicates with the seventh refrigerant pipe 28 via a previously formed refrigerant circulation hole 28a.
The seventh refrigerant pipe 28 communicates the second chamber 55b of the lower header tank 55 and the receiver tank 52, and corresponds to the “first communication pipe” of the present invention.

The third chamber 55c of the lower header tank 55 communicates with the eighth refrigerant pipe 29 through a previously formed refrigerant circulation hole 29a.
The eighth refrigerant pipe 29 communicates the third chamber 55c of the lower header tank 55 and the receiver tank 52, and corresponds to the “second communication pipe” of the present invention.

  Next, the outline of the refrigerant flow in the vehicle exterior heat exchanger 5 will be described.

  As shown in FIG. 4A, when the vehicle exterior heat exchanger 5 functions as a condenser, the refrigerant from the first refrigerant pipe 9 flows into the first chamber 54a of the upper header tank 54, and 1 pass 101, first chamber 55a of lower header tank 55, second pass 102, second chamber 54b of upper header tank 54, third pass 103, second chamber 55b of lower header tank 55 Then, it flows out to the receiver tank 52 through the seventh refrigerant pipe 28. At this time, the refrigerant is condensed and liquefied by exchanging heat (dissipating heat) with the outside air in the first to third passes 101 to 103. That is, the first to third paths 101 to 103 condense the refrigerant corresponding to the refrigerant condensing unit 51 and the “first tube group” of the present invention.

  In addition, the refrigerant that has passed through the receiver tank 52 flows into the third chamber 55c of the lower header tank 55 via the eighth refrigerant pipe 29, and the fourth chamber 104c and the third chamber 54c of the upper header tank 54. Then, it flows out to the third refrigerant pipe 14. At this time, the refrigerant is supercooled by exchanging heat with the outside air (dissipating heat) in the fourth path 104. That is, the fourth pass 104 supercools the refrigerant in correspondence with the subcool portion 53 and the “second tube group” of the present invention.

Therefore, the separators 62 and 64 divide the plurality of tubes 56 into the refrigerant condensing unit 51 and the subcooling unit 53.
The separators 61 and 63 divide the plurality of tubes 56 constituting the refrigerant condensing unit 51 into three tube groups including the first path 101 to the third path 103.

  On the other hand, as shown in FIG. 4B, when the vehicle exterior heat exchanger 5 functions as an evaporator, the refrigerant from the third refrigerant pipe 14 flows into the third chamber 54c of the upper header tank 54. Through the fourth path 104 and the third chamber 55 c of the lower header tank 55, the refrigerant flows out to the receiver tank 52 through the eighth refrigerant pipe 29. At this time, a part of the refrigerant is gasified by exchanging heat (absorbing heat) with the outside air in the fourth pass 104. That is, a part of the refrigerant evaporates in the subcool portion 53 (second tube group).

  The refrigerant that has passed through the receiver tank 52 flows into the second chamber 55b of the lower header tank 55 via the seventh refrigerant pipe 28, and passes through the third path 103 and the second chamber 54b of the upper header tank 54. Then, it flows out to the first refrigerant pipe 9 through the second path 102, the first chamber 55a of the lower header tank 55, the first path 101, and the first chamber 54a of the upper header tank 54. At this time, heat exchange with the outside air (heat absorption) is performed in the first to third passes 103, and the remaining refrigerant is gasified. That is, the remaining refrigerant evaporates in the refrigerant condensing unit 51 (first tube group).

  Here, the tube numbers N1 to N4 of the first to fourth paths 101 to 104 satisfy the relationship of N1 ≧ N2 ≧ N3 ≧ N4 as shown in the above-described equation (1). Therefore, when the total flow passage cross-sectional area of each of the first to fourth passes 101 to 104 (the sum of the cross-sectional areas of the tubes 56 in each pass) is S1 to S4, S1 to S4 are expressed by the following formula (3). Meet the relationship.

    S1 ≧ S2 ≧ S3 ≧ S4 (3)

  Accordingly, in the first to third passes 101 to 103, the total flow passage cross-sectional areas S1 to S3 are not less than the total flow passage cross-sectional area S4 of the fourth pass 104. In other words, the channel cross-sectional area of the refrigerant condensing unit 51 is equal to or larger than the channel cross-sectional area of the subcool unit 53. As a result, when the vehicle exterior heat exchanger 5 functions as an evaporator, the refrigerant flows from the subcooling portion 53 to the refrigerant evaporation portion 51, and the evaporation of the refrigerant proceeds. As a result, the density of the refrigerant decreases. The flow rate fluctuation can be offset by the flow rate fluctuation due to the increase in the cross-sectional area of the flow path, and thus the refrigerant flow rate can be stabilized.

  If the flow passage cross-sectional area of the seventh refrigerant pipe 28 is S5 and the flow passage cross-sectional area S6 of the eighth refrigerant pipe 29 is S3 to S6, the relationship of the following equation (4) is satisfied.

      S3 ≧ S5 ≧ S6 ≧ S4 (4)

  Next, optimization of the refrigerant condensing capacity of the exterior heat exchanger 5 will be described with reference to FIG.

  FIG. 5 shows the relationship between the refrigerant temperature decrease amount and the subcool occupancy rate in the exterior heat exchanger 5 when the exterior heat exchanger 5 functions as a condenser. Here, the subcool occupancy is an area ratio of the subcool portion 53 (second tube group) to the refrigerant condensing portion 51 (first tube group) and the subcool portion 53 (second tube group), in other words. For example, the ratio is the ratio of the total surface area of the tubes 56 in the subcool portion 53 to the total surface area of the tubes 56 in the refrigerant condensing portion 51 and the subcool portion 53. Therefore, the subcool occupation ratio is, for example, the ratio of the number of tubes (N4) of the subcool portion 53 to the total number of tubes (N1 + N2 + N3 + N4) of the refrigerant condensing portion 51 and the subcool portion 53.

  As shown in FIG. 5, when the subcool occupancy is smaller than 10.0%, the temperature decrease amount of the refrigerant in the vehicle exterior heat exchanger 5 becomes less than 8 ° C. Further, as the subcool occupancy becomes smaller than 10.0%, the amount of refrigerant temperature decrease in the exterior heat exchanger 5 decreases relatively abruptly. That is, as the subcool occupancy becomes smaller than 10.0%, the amount of decrease in the refrigerant condensing capacity of the vehicle exterior heat exchanger 5 increases. This is because if the subcool occupancy is smaller than 10.0%, the subcool portion 53 does not sufficiently cool the refrigerant, so that the sensible heat change in the subcool portion 53 is not sufficiently performed. One possible reason is that the temperature of the refrigerant does not drop sufficiently.

  Further, when the subcool occupancy is larger than 16.7%, the temperature drop amount of the refrigerant in the vehicle exterior heat exchanger 5 becomes less than 8 ° C. Further, as the subcool occupancy is larger than 16.7%, the amount of refrigerant temperature decrease in the vehicle exterior heat exchanger 5 decreases relatively abruptly. That is, as the subcool occupancy becomes larger than 16.7%, the amount of decrease in the refrigerant condensing capacity of the vehicle exterior heat exchanger 5 increases. This is because, if the subcool occupancy is larger than 16.7%, the region of the refrigerant condensing part 51 where the refrigerant latent heat changes is narrowed, the condensing pressure rises, and the refrigerant condensing capacity decreases. It is believed that there is.

  Based on these findings, the present inventor sets the subcool occupancy within the range of 10.0 to 16.7% (within the subcool occupancy Psc shown in FIG. 5), thereby enabling the heat exchanger outside the vehicle interior. It has been found that a good refrigerant condensing capacity of 5 can be obtained. For this reason, in this embodiment, the subcool occupancy is in the range of 10.0 to 16.7%. If the number of tubes in each of the first to fourth paths 101 to 104 of the vehicle exterior heat exchanger 5 is the above formula (2), the subcool occupancy is (15 / (40 + 28 + 26 + 15)) × 100 = 13 8%.

  Next, details of the receiver tank 52 will be described with reference to FIG. 6 in addition to FIG. 3 and FIG.

FIG. 6 shows a schematic configuration of the receiver tank 52.
The receiver tank 52 is erected in parallel with the plurality of tubes 56, and includes a covered cylindrical body 70 made of metal and having a lower surface opening, and a bottom member 71 that closes the lower surface opening of the body 70.

The upper part of the body 70 is attached to the right frame 31 of the vehicle exterior heat exchanger 5 via the attachment member 30. Here, the right frame 31 extends in the vertical direction, and both ends thereof are fixed to the end portions of the header tanks 54 and 55 (see FIG. 3A).
Moreover, the lower part of the bottom part member 71 is attached to the edge part of the lower header tank 55 via the attachment member 32 (refer Fig.3 (a)).

A hygroscopic agent 72 is filled in the upper side of the body 70, and a filter 73 made of a nonwoven fabric or the like is disposed below the hygroscopic agent 72.
A reinforcing plate 74 made of punch metal or the like is disposed below the filter 73, and the reinforcing plate 74 is fixed to the body 70 by a notch processing portion 75.

The bottom member 71 is formed with two communication holes 76 and 77 communicating with the inside and outside of the receiver tank 52.
The open end of the seventh refrigerant pipe 28 is connected to the lower end of the communication hole 76 of the bottom member 71. Here, the upper surface opening 76a of the communication hole 76 corresponds to the “first refrigerant circulation port” of the present invention.
The open end of the eighth refrigerant pipe 29 is connected to the lower end of the communication hole 77 of the bottom member 71. Here, the upper surface opening 77a of the communication hole 77 corresponds to the “second refrigerant circulation port” of the present invention.

  A strainer 78 is inserted into the communication hole 77 of the bottom member 71. The strainer 78 includes a circular pipe member 78a having an outer diameter slightly smaller than the inner diameter of the communication hole 77, and a mesh member 78b that covers the upper surface of the circular pipe member 78a.

The receiver tank 52 has a function of performing gas-liquid separation of the refrigerant and a function of storing the liquid refrigerant. These functions are realized especially when the vehicle exterior heat exchanger 5 functions as a condenser.
The wire diameter, mesh size, opening ratio, etc. of the mesh member 78b of the strainer 78 are set so that the refrigerant flow rate can realize these functions of the receiver tank 52. In other words, the strainer 78 functions as the “flow rate adjusting unit” of the present invention to adjust the flow rate of the refrigerant, thereby realizing the gas-liquid separation function and the refrigerant storage function of the receiver tank 52.

  In the present embodiment, the strainer 78 is described as the flow rate adjusting unit that adjusts the flow rate of the refrigerant flowing through the receiver tank 52, but the configuration of the flow rate adjusting unit is not limited thereto.

FIG. 7 shows a modification of the flow rate adjustment unit.
FIG. 7A shows an example in which an orifice 79 is inserted into the communication hole 76 as a flow rate adjusting unit. FIG. 7B shows an example in which a cylindrical member 80 having a stepped portion 80 a on the inner surface is inserted into the communication hole 76 as a flow rate adjusting portion.

  A flow rate adjustment unit such as a strainer 78, an orifice 79, and a cylindrical member 80 having a stepped portion 80a is installed in at least one of the communication holes 76 and 77 so as to realize a gas-liquid separation function and a refrigerant storage function of the receiver tank 52. The

  According to the present embodiment, the vehicle exterior heat exchanger 5 includes a pair of upper and lower header tanks 54 and 55 extending in parallel to each other, a plurality of tubes 56 communicating with the pair of header tanks 54 and 55, and each header tank 54. 55, separators 62 and 64 that divide the plurality of tubes 56 into two tube groups each including the refrigerant condensing unit 51 and the subcooling unit 53 (first and second tube groups), and a plurality of tubes 56, respectively. A receiver tank 52 erected in parallel with the receiver tank 52, a portion of the lower header tank 55 that communicates with the refrigerant condensing unit 51 (second chamber 55b), and a seventh refrigerant pipe 28 that communicates with the receiver tank 52 ( A first communication pipe), a portion of the lower header tank 55 that communicates with the subcool portion 53 (third chamber 55c), and an eighth refrigerant distribution that communicates with the receiver tank 52. 29 (second communicating pipe) configured to include a. The receiver tank 52 has an upper surface opening 76 a (first refrigerant flow port) of the through hole 76 connected to the opening end of the seventh refrigerant pipe 28 and an opening end of the eighth refrigerant pipe 29 at the bottom (bottom member 71). And an upper surface opening 77a (second refrigerant circulation port) of the through-hole 77 connected to. Thereby, when the vehicle exterior heat exchanger 5 functions as an evaporator, the refrigerant from the subcool portion 53 flows into the receiver tank 52 through the eighth refrigerant pipe 29 and the upper surface opening 77a of the through hole 77, Furthermore, since the refrigerant flows through the upper surface opening 76a of the through hole 76 and the seventh refrigerant pipe 28 to the refrigerant condensing part 51, the refrigerant can flow relatively smoothly through the receiver tank 52, and the refrigerant flow rate is stabilized. Can be made.

  Further, according to the present embodiment, when the vehicle exterior heat exchanger 5 functions as a condenser, the refrigerant passes through the seventh refrigerant passage 28, the receiver tank 52, and the eighth refrigerant pipe 29 from the refrigerant condensing unit 51 and is subcooled. By flowing to the section 53, the refrigerant is condensed in the refrigerant condensing section 51 and the refrigerant is supercooled in the subcool section 53. As a result, the refrigerant can be well condensed and dissipated in the vehicle exterior heat exchanger 5, so that the vehicle interior evaporator 6 can perform good heat absorption, and thus the vehicle air conditioner 1 is excellent. Cooling performance can be obtained.

  Further, according to the present embodiment, when the vehicle exterior heat exchanger 5 functions as an evaporator, the refrigerant condenses from the subcool portion 53 through the eighth refrigerant pipe 29, the receiver tank 52, and the seventh refrigerant pipe 28. By flowing to the unit 51, the refrigerant evaporates in the refrigerant condensing unit 51 and the subcooling unit 53. As a result, in the outdoor heat exchanger 5 with the receiver tank 52, the refrigerant can be gasified not only in the refrigerant condensing part 51 but also in the subcooling part 53, so that a sufficient heat absorption area can be secured. Thereby, since favorable heat radiation can be performed by the vehicle interior condenser 4, good heating performance of the vehicle air conditioner 1 can be obtained.

  Further, according to the present embodiment, the plurality of tubes 56 constituting the refrigerant condensing unit 51 are divided into a plurality of tube groups (first to first) by the separators 61 and 63 further provided in at least one of the pair of header tanks 54 and 55. The first to third passes 101 to 103 are divided into total passage cross-sectional areas S1 to S3, and the total passage cross-sectional area S4 of the fourth pass 104 (subcool portion 53). That's it. As a result, when the vehicle exterior heat exchanger 5 functions as an evaporator, the refrigerant flows from the subcooling portion 53 to the refrigerant condensing portion 51 and the refrigerant evaporates to decrease the density of the refrigerant. The flow rate fluctuation can be offset by the flow rate fluctuation due to the increase in the cross-sectional area of the flow path, and thus the refrigerant flow rate can be stabilized.

  Further, according to the present embodiment, the flow rate adjusting unit (strainer 78, orifice 79, cylinder with stepped portion 80 a) that adjusts the flow rate of the refrigerant in at least one of the communication holes 76 and 77 of the bottom portion (bottom member 71) of the receiver tank 52. By providing the member 80), the gas-liquid separation function and the refrigerant storage function of the receiver tank 52 can be realized.

  Moreover, according to this embodiment, when the subcool occupancy is in the range of 10.0% to 16.7%, the vehicle exterior heat exchanger is used when the vehicle exterior heat exchanger 5 functions as a condenser. Since the refrigerant flowing through the refrigerant 5 has a good latent heat change in the refrigerant condensing part 51 and also a good sensible heat change in the subcooling part 53, it is possible to obtain a good refrigerant condensing capacity of the outdoor heat exchanger 5. it can.

  In addition, according to the present embodiment, the subcool occupancy is the ratio of the number of tubes (N4) of the subcool portion 53 to the total number of tubes (N1 + N2 + N3 + N4) of the refrigerant condensing portion 51 and the subcool portion 53. It can be realized easily.

  Further, according to the present embodiment, the upper header tank 54 is further provided with the third refrigerant pipe 14 (refrigerant circulation pipe) through which the refrigerant flows by being connected to a portion (third chamber 54c) communicating with the subcool portion 53. The flow path cross-sectional area of the third refrigerant pipe 14 is equal to or less than the total flow path cross-sectional area S4 of the subcool portion 53. Thereby, when the vehicle exterior heat exchanger 5 functions as an evaporator, the pressure loss of the refrigerant flowing from the third refrigerant pipe 14 to the subcool portion 53 can be reduced, so that the vehicle air conditioner 1 is good. Heating performance can be obtained.

  The illustrated embodiments are merely examples of the present invention, and the present invention is not limited to those directly described by the described embodiments, and various improvements and modifications made by those skilled in the art within the scope of the claims. Needless to say, it encompasses changes.

DESCRIPTION OF SYMBOLS 1 Vehicle air conditioner 2 Compressor 3 Air passage 4 Car interior condenser 5 Car exterior heat exchanger 6 Car interior evaporator 7 Fan 8 Damper 9 First refrigerant pipe 9a Refrigerant flow hole 10 First on-off valve 11 Second refrigerant pipe 12 Second 2 On-off valve 13 Accumulator 14 Third refrigerant pipe (refrigerant flow pipe)
14a Refrigerant flow hole 15 Third on-off valve 16 First check valve 17 Internal heat exchanger 17A High temperature part 17B Low temperature part 18 First expansion valve 19 Fourth refrigerant pipe 20 Fourth on-off valve 21 Fifth refrigerant pipe 23 Second expansion Valve 24 Second check valve 25 Sixth refrigerant pipe 27 Fifth on-off valve 28 Seventh refrigerant pipe (first communication pipe)
28a Refrigerant flow hole 29 Eighth refrigerant pipe (second communication pipe)
29a Refrigerant circulation hole 30 Mounting member 31 Right frame 32 Mounting member 51 Refrigerant condensing part (first tube group)
52 Receiver tank 53 Subcool section (second tube group)
54 Upper header tank 54a First chamber 54b Second chamber 54c Third chamber 55 Lower header tank 55a First chamber 55b Second chamber 55c Third chamber 56 Tube 57 Corrugated fins 61 to 64 Separator 70 Body 71 Bottom member 72 Hygroscopic agent 73 Filter 74 Reinforcement plate 75 Notch processing portion 76 Communication hole 76a Upper surface opening (first refrigerant circulation port)
77 Communication hole 77a Upper surface opening (second refrigerant flow port)
78 Strainer 78a Circular pipe member 78b Mesh member 79 Orifice 80 Cylindrical member 80a Step 101 First pass 102 Second pass 103 Third pass 104 Fourth pass

Claims (6)

A pair of upper and lower header tanks extending parallel to each other;
A plurality of tubes communicating with the pair of header tanks;
A separator that is provided in each header tank and divides the plurality of tubes into two tube groups each consisting of a first tube group and a second tube group;
A receiver tank erected parallel to the plurality of tubes;
A first communication pipe that communicates the receiver tank with a portion communicating with the first tube group in the lower header tank;
A second communication pipe that communicates a portion of the lower header tank communicating with the second tube group and the receiver tank;
A heat exchanger comprising:
The receiver tank has a first refrigerant flow port connected to an open end of the first communication pipe and a second refrigerant flow port connected to an open end of the second communication pipe at the bottom of the receiver tank. Prepared,
When the heat exchanger functions as a condenser, the refrigerant passes from the first tube group to the second tube group through the first communication pipe, the receiver tank, and the second communication pipe. By flowing, the refrigerant is condensed in the first tube group, and the refrigerant is subcooled in the second tube group,
When the heat exchanger functions as an evaporator, the refrigerant passes from the second tube group to the first tube group through the second communication pipe, the receiver tank, and the first communication pipe. The heat exchanger is characterized in that the refrigerant evaporates in the first and second tube groups by flowing.   The plurality of tubes constituting the first tube group are further divided into a plurality of tube groups by a separator further provided in at least one of the pair of header tanks. 2. The heat exchanger according to claim 1, wherein a cross-sectional area is equal to or larger than a total flow path cross-sectional area of the second tube group.   3. The heat exchanger according to claim 1, further comprising a flow rate adjusting unit that adjusts a flow rate of the refrigerant in at least one of the first and second refrigerant circulation ports at the bottom of the receiver tank.   The subcool occupancy, which is the area ratio of the second tube group to the first and second tube groups, is in the range of 10.0% to 16.7%. The heat exchanger according to any one of 3.   5. The heat exchanger according to claim 4, wherein the subcool occupation ratio is a ratio of the number of tubes of the second tube group to the total number of tubes of the first and second tube groups.   It further includes a refrigerant flow pipe that is connected to a portion of the upper header tank that communicates with the second tube group and through which the refrigerant flows. The refrigerant flow pipe has a flow passage cross-sectional area that is the second tube group. The heat exchanger according to any one of claims 1 to 5, wherein the heat exchanger has a total cross-sectional area of less than or equal to.