JP2007232287A - Heat exchanger and integral type heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger capable of preventing hunting by eliminating accumulation of oil without deteriorating heat radiation performance. <P>SOLUTION: A coolant is sent upward from a downwind side of a fist header tank 40, is turned around in a second header tank 50, and is sent downward from an upwind side. Oil accumulated in interiors of the second header tank 50 and a first heat exchanger core 20 can be sent downward along with the coolant. A heat exchange area becomes large in comparison with a single pass, and since turning of the coolant is facilitated, passage resistance can be reduced in comparison with a three pass. Thereby, accumulation of oil can be eliminated without deteriorating the heat radiation performance, and hunting can be prevented. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat exchanger used as an air conditioner for a vehicle, and more particularly to a heat exchanger structure suitable for an integrated condenser radiator (hereinafter referred to as UCR).

  In the following description, the integrated gas cooler / radiator corresponding to the CO2 refrigerant is also referred to as UCR.

  In general, in an engine room provided in the front part of an automobile, a radiator for cooling engine cooling water including an engine for driving a vehicle, and a condenser (gas cooler) for cooling and condensing a refrigerant of an air conditioner It is equipped with a heat exchanger such as a cooling fan. Among these, the condenser and the radiator are arranged in the engine room in close proximity to each other so that the condenser is located on the windward side and the radiator is located on the leeward side. Also, integrated capacitor radiators that combine capacitors and radiators into one are becoming popular.

  By the way, refrigerant and compressor lubricating oil circulate in the refrigeration cycle of the air conditioner. In this refrigeration cycle, if liquid refrigerant or oil stays inside the condenser that condenses the refrigerant, the refrigerant passage temporarily narrows, and the refrigerant pressure increases. And when this pressure becomes more than a certain pressure, the oil which stayed is pushed away by the refrigerant and the pressure drops. When the refrigerant pressure is repeatedly increased and decreased during the operation of the refrigeration cycle, the refrigeration cycle hunting is caused, and the temperature of the conditioned air also varies accordingly. In particular, in a vertical flow type condenser in which the refrigerant flows in the vertical direction, hunting due to oil retention tends to occur, and in order to make the oil flow easily, it is desirable to use a horizontal flow type.

  In the UCR described above, for common fins, the flow of the radiator is also a lateral flow as with the capacitor. However, it is desirable that the radiator be of a longitudinal flow type in order to remove air remaining in the cooling passage and increase the ventilation area for heat exchange. In addition, since the radiator is laid out between the cross members at the front part of the vehicle body, in the case of the transverse flow type, the heat exchange portion is arranged avoiding the cross member where the cooling air does not flow, and thus the ventilation area of the radiator is reduced. For this reason, it is possible to increase the thickness, but this makes it impossible to effectively use the space in the engine room.

  Thus, a heat exchanger in which a transverse flow type condenser and a longitudinal flow type radiator are combined has been proposed (see Patent Document 1).

Further, regarding a vertical flow type capacitor, a heat exchanger has been proposed in which communicating tube elements are connected in communication with a bulged header (see Patent Document 2). Similarly for the vertical flow type condenser, the heat exchange area is 3 passes, and the passage area of the passage where the refrigerant flows upward and the passage resistance of the inner fins are reduced to increase the flow velocity and make it easier to discharge oil. Has been proposed (see Patent Document 3).
JP 2001-311597 A JP-A-7-332890 JP-A-10-220919

  However, in the heat exchanger described in Patent Document 1, since the fin directions of the condenser and the radiator are different, when configured as a UCR, it is not possible to achieve integration of parts or simplification of the structure, thereby reducing the cost. Will be difficult. Further, in the heat exchanger described in Patent Document 2, there is little influence due to oil retention in one pass, but in that case, since the distance from the refrigerant inlet to the refrigerant outlet of the condenser is shortened, the heat dissipation performance There is concern about the decline. Furthermore, in the capacitor described in Patent Document 3, the flow velocity is adjusted by adjusting the passage area of the path and adjusting the passage resistance of the inner fin, so that the passage resistance of the refrigerant may increase depending on the product specifications and usage conditions. Conceivable.

  An object of the present invention is to reduce the cost when a heat exchanger that can prevent hunting due to oil stagnation without degrading heat dissipation performance and a UCR in addition to the above object. It is to provide a body heat exchanger.

  In order to achieve the above object, a heat exchanger according to claim 1 is a heat exchanger that cools an air-conditioning refrigerant with cooling air, and the first heat is arranged forward and backward with respect to the flow direction of the cooling air. An exchanger core, a second heat exchanger core, and two independent tank portions are provided, and a tank portion on the leeward side of the cooling air communicates with a refrigerant inlet side of the second heat exchanger core and becomes an upwind side The tank portion is provided below, communicating with the refrigerant outlet side of the first heat exchanger core, introducing the refrigerant from the tank portion on the leeward side, and discharging the refrigerant from the tank portion on the leeward side. The first header tank communicates with the refrigerant outlet side of the second heat exchanger core and the refrigerant inlet side of the first heat exchanger core, and the refrigerant that has passed through the second heat exchanger core passes through the first heat tank. The second header provided above that flows into the exchanger core side Characterized in that a tank.

  A heat exchanger according to a second aspect is characterized in that, in the first aspect, two independent tank portions are arranged separately in the front-rear direction as viewed from the flow direction of the cooling air.

  A heat exchanger according to a third aspect is the heat exchanger according to any one of the first or second aspects, wherein a slit is provided along the longitudinal direction between two independent tank portions, and the two tank portions are arranged at least at one location. It is connected.

  An integrated heat exchanger according to claim 4 is characterized in that a radiator for cooling engine cooling water is provided on the leeward side of the heat exchanger according to any one of claims 1 to 3 and integrated. To do.

  According to the first aspect of the present invention, the refrigerant flows from the leeward side to the upper side of the first header tank, is turned by the second header tank, and flows from the leeward side to the lower side. Or the oil inside the heat exchanger core can flow downward together with the refrigerant. Therefore, the refrigerant pressure does not rise or fall during the operation of the refrigeration cycle, and hunting can be suppressed, so that the temperature of the conditioned air can be kept constant.

  In addition, since the refrigerant passage has two paths, the heat exchange area becomes larger than that in the first path, and the refrigerant can be easily turned. Therefore, the passage resistance can be reduced as compared with the three paths. For this reason, although it is a longitudinal flow type heat exchanger, it is possible to prevent oil stagnation and hunting without deteriorating heat dissipation performance.

  According to the invention of claim 2, the heat of the refrigerant introduced into the tank portion on the leeward side of the first header tank is cooled with the cooling air while passing from the first heat exchanger core to the second heat exchanger core. Since it is not transmitted to the refrigerant having a low temperature after heat exchange, the heat exchange efficiency can be improved.

  According to the invention of claim 3, heat is more difficult to be transferred from the leeward tank portion where the high-temperature refrigerant is introduced to the leeward tank portion where the low-temperature refrigerant is discharged, thereby further improving the heat exchange efficiency. Can be made.

  According to the invention of claim 4, by combining with a longitudinal flow type radiator, it is possible to achieve the integration of parts and the simplification of the structure, so that the cost can be reduced. In addition, even when laid out between the cross members of the car body, the upper and lower header tanks can be arranged on the back side of the cross member, so the ventilation area is not reduced and the thickness needs to be increased as with the transverse flow type radiator. Since there is no space, the space in the engine room can be used effectively.

  Hereinafter, embodiments of a heat exchanger and an integrated heat exchanger according to the present invention will be described. Here, an example in which the heat exchanger according to the present invention is applied to a longitudinal flow type gas cooler using CO2 as a refrigerant will be described.

  FIG. 1 is a perspective view of a gas cooler according to the present embodiment, and FIG. 2 is a longitudinal sectional view of FIG. As shown in FIG. 1, the gas cooler 10 according to the present embodiment includes a first heat exchanger core 20 and a second heat exchanger core 30 that perform heat exchange between the refrigerant circulating inside and the cooling air 60. A first header tank 40 and a second header tank 50 joined to the upper and lower ends of the first heat exchanger core 20 and the second heat exchanger core 30 are provided.

  The first heat exchanger core 20 and the second heat exchanger core 30 include a tube 21 having a multi-hole tube structure in which a plurality of tube holes (not shown) serving as refrigerant passages are formed therein, and a cooling tube formed into a corrugated shape. The fins 22 are alternately stacked. And the 1st heat exchanger core 20 and the 2nd heat exchanger core 30 are arrange | positioned in order of the flow direction of the cooling air 60 in order.

  The first header tank 40 is disposed below the first and second heat exchanger cores 20 and 30 as shown in FIG. 2 and is formed by joining two plates 41 and 42 and brazing them together. A first tank part 43 and a second tank part 44 having a substantially semicircular cross section serving as a refrigerant flow path are formed. The first tank portion 43 and the second tank portion 44 are partitioned by the central portion of the main body of the first header tank 40, and are configured as independent tank portions that do not communicate with each other inside. Note that a refrigerant supply pipe is connected to the first tank portion 43 and a refrigerant discharge pipe is connected to the second tank portion 44 (both are not shown).

  Of the first header tank 40, the first tank portion 43 that is on the leeward side when viewed from the flow direction of the cooling air 60 communicates with the refrigerant inlet side of the second heat exchanger core 30 and is the second tank that is on the windward side. The part 44 communicates with the refrigerant outlet side of the first heat exchanger core 20. As a result, the refrigerant is introduced from the first tank portion 43 on the leeward side and discharged from the second tank portion 44 on the leeward side.

  As shown in FIG. 2, the second header tank 50 is disposed above the first heat exchanger cores 20 and 30 and is formed by superposing and brazing and joining two plates 51 and 52. A first tank portion 53 and a second tank portion 54 that are substantially semicircular in cross section and serve as a refrigerant flow passage are formed. A communication passage 55 is formed between the first tank portion 53 and the second tank portion 54, and both tank portions are configured to communicate with each other.

  Of the second header tank 50, the first tank portion 53 communicates with the refrigerant outlet side of the second heat exchanger core 30, and the second tank portion 54 communicates with the refrigerant inlet side of the first heat exchanger core 20. ing. As a result, the refrigerant that has passed through the second heat exchanger core 30 flows from the first tank portion 53 of the second header tank 50 into the second tank portion 54 via the communication passage 55 and further flows into the first heat exchanger core 20. Will do.

  In the gas cooler 10 configured as described above, the refrigerant introduced from the first tank portion 43 of the first header tank 40 flows upward through the tube hole 21a (see FIG. 2) of the second heat exchanger core 30. It flows into the first tank portion 53 of the second header tank 50. Then, the refrigerant flows from the communication path 55 to the second tank portion 54, and further flows downward through the tube hole 21a of the first heat exchanger core 20 to the second tank portion 44 of the first header tank 40, from here to the outside To be discharged. During this time, when the refrigerant passes through each heat exchanger core, heat exchange is performed with the cooling air 60 flowing from the direction orthogonal to the flow direction of the refrigerant.

  FIG. 3 is a ph diagram showing the operation of the refrigeration cycle using the CO 2 refrigerant, and shows the cycle balance during cooling. In FIG. 3, the section (ab) on the high pressure side that is equal to or higher than the critical point shows the change in the gas cooler. When the outside air temperature is a high load such as 40 ° C., the refrigerant is in a gas state near the outlet of the gas cooler 10 and can maintain a high flow rate even in a longitudinal flow, so that no oil stays. On the other hand, when the outside air temperature is a low load such as 15 ° C., the refrigerant condenses and becomes a liquid refrigerant. However, when the refrigerant passes through the first pass (second heat exchanger core 30), it is in a gas state and has a high flow rate, so that it is easy to discharge oil, and the second pass (first heat exchanger core 20). ), The liquid refrigerant flows downward due to its own weight, so that the oil can be easily discharged and is not retained.

  As described above, according to the configuration of the present embodiment, the refrigerant flows from the leeward side of the first header tank 40 upward, is caused to make a U-turn in the second header tank 50, and the refrigerant flows downward from the leeward side. As a result, the oil can flow downward in the second header tank 50 and the first heat exchanger core 20 without being retained with the refrigerant. Therefore, the refrigerant pressure does not rise or fall during the operation of the refrigeration cycle, and hunting can be suppressed, so that the temperature of the conditioned air can be kept constant.

  In addition, since the refrigerant passage has two paths in the configuration of the present embodiment, the heat exchange area is larger than that of the first path, and the refrigerant is easily turned, so that the passage resistance is reduced as compared with the three paths. it can. For this reason, although it is a longitudinal flow type gas cooler, it is possible to prevent hunting due to oil stagnation without degrading the heat dissipation performance.

  In addition, since the refrigerant is introduced from the leeward side (first tank portion 43) of the first header tank 40, even if the cooling air that has passed through the first and second heat exchanger cores blows back, Therefore, the influence on the heat radiation performance can be reduced.

  In addition, since the first tank portion 43 and the second tank portion 44 are arranged separately in the front-rear direction when viewed from the flow direction of the cooling air, the refrigerant introduced into the first tank portion 43 of the first header tank 40. Heat is not transferred to the refrigerant that has become a low temperature by exchanging heat with the cooling air while passing through the second heat exchanger core 30 from the first heat exchanger core 20, thereby improving the heat exchange efficiency Can do.

  In addition, as shown in FIG. 2, slits 41 a and 42 a are provided along the longitudinal direction in the central portions of the plates 41 and 42 constituting the first tank portion 43 and the second tank portion 44, and these two tank portions 43, 44 may be connected in at least one place (preferably a plurality of places). By providing such slits 41a and 42a, heat is more difficult to be transferred from the first tank portion 43 into which the high-temperature refrigerant is introduced to the second tank portion 44 through which the low-temperature refrigerant is discharged. Can be further improved.

  Further, when the slits 41a and 42a as described above are provided, a shielding member 45 is attached so as to cover the space between the first tank portion 43 and the second tank portion 44 as shown in FIG. May be. By providing such a shielding member 45, it is possible to prevent the cooling air that has passed through the first heat exchanger core 20 on the windward side from falling downward from the slits 41a and 42a. A decrease in heat exchange efficiency can be suppressed. As the shielding member 45, a resin material having a low thermal conductivity is used in order to make it difficult for heat to be transmitted from the first tank portion 43 to the second tank portion 44 side.

  Moreover, as shown in FIG. 4, the gas cooler 10 of this embodiment can also be integrated with a radiator and comprised as a UCR. FIG. 4 shows a longitudinal sectional view of a UCR 100 in which a longitudinal flow type radiator 70 is provided on the leeward side of the gas cooler 10 and integrated.

  As shown in FIG. 4, the gas cooler 10 according to the present embodiment can be integrated with parts and simplified in structure by combining with a longitudinal flow type radiator 70, thereby realizing low cost. it can. Further, even when laid out between the cross members of the vehicle body, the ventilation area is not reduced and the thickness does not need to be increased unlike a cross-flow type radiator, so that the space in the engine room can be used effectively. According to this, the cooling capacity of the engine can be improved, and the size can be reduced as compared with the transverse flow type radiator. In addition, the amount of engine cooling water can be reduced, which can contribute to weight reduction of the vehicle.

The perspective view of the gas cooler concerning an embodiment. The longitudinal cross-sectional view of FIG. The ph diagram which shows the effect | action of the refrigerating cycle using a CO2 refrigerant | coolant. Sectional drawing at the time of comprising the gas cooler of embodiment as UCR.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Gas cooler 20 ... 1st heat exchanger core 21 ... Tube 21a ... Tube hole 22 ... Fin 30 ... 2nd heat exchanger core 40 ... 1st header tank 43 ... 1st tank part 44 ... 2nd tank part 50 ... 1st 2 Header tank 53 ... 1st tank part 54 ... 2nd tank part 55 ... Communication path 60 ... Cooling air 70 ... Radiator 100 ... UCR

Claims (4)

A heat exchanger that cools the air-conditioning refrigerant with cooling air,
A first heat exchanger core (20) and a second heat exchanger core (30) arranged in front and rear with respect to the flow direction of the cooling air;
A tank provided with two independent tank parts (43, 44), the tank part (43) on the leeward side of the cooling air communicates with the refrigerant inlet side of the second heat exchanger core (30), and is on the windward side The portion (44) communicates with the refrigerant outlet side of the first heat exchanger core (20) and introduces refrigerant from the tank portion (43) on the leeward side, so that the tank portion (44) on the leeward side. A first header tank (40) provided below, for discharging the refrigerant from
The refrigerant that communicated with the refrigerant outlet side of the second heat exchanger core (30) and the refrigerant inlet side of the first heat exchanger core (20), respectively, and that has passed through the second heat exchanger core (30) A second header tank (50) provided above, which is caused to flow into the first heat exchanger core (20),
A heat exchanger comprising:   2. The heat exchanger according to claim 1, wherein the two independent tank portions (43, 44) are arranged separately in the front-rear direction when viewed from the flow direction of the cooling air.   The heat exchanger according to any one of claims 1 and 2, wherein a slit (41a, 42a) is provided along a longitudinal direction between two independent tank portions (43, 44), and the two tanks are provided. The heat exchanger characterized by connecting a part (43, 44) in at least one place.   An integrated heat exchanger characterized in that a radiator (70) for cooling engine cooling water is provided and integrated on the leeward side of the heat exchanger according to any one of claims 1 to 3.

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