WO2013123144A1

WO2013123144A1 - Evaporator having separate air flow paths and method of manufacturing the same

Info

Publication number: WO2013123144A1
Application number: PCT/US2013/026070
Authority: WO
Inventors: Kristen A. GERSTUNG; David G. Schmidt; Terry J. HUNT; Martin J. FRANCO
Original assignee: Delphi Technologies, Inc.
Priority date: 2012-02-14
Filing date: 2013-02-14
Publication date: 2013-08-22

Abstract

A heat exchanger assembly (20) is provided that includes a manifold (22) and a heat exchanger core (44) defined by a plurality of corrugated fins (42) having louvers (64) disposed between a plurality of tubes (34) extending from the manifold (22). The corrugated fins (42) include a plurality of closed louvers (64) at a predetermined region along a length of the corrugated fins (42). The plurality of closed louvers (64) defines a partition (66) separating the heat exchanger core (44) into a first portion (68) and a second portion (70). The seams (76) of the closed louvers (64) may contain a braze alloy material (80) to seal the closed louvers (64) to restrict the air flow through the heat exchanger core (44) between the first and second portions (68, 70).

Description

EVAPORATOR HAVING SEPARATE AIR FLOW PATHS

AND METHOD OF MANUFACTURING THE SAME

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of United States Provisional Patent

Application Serial No. 61/598,483 for an EVAPORATOR HAVING SEPARATE AIR FLOW PATHS AND METHOD OF MANUFACTURING THE SAME, filed on February 14, 2012, which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD OF INVENTION

[0002] The present invention relates to a heat exchanger having tubes and fins; more particularly, to a heat exchanger having tubes and fins adapted for use in a dual- integrated HVAC system.

BACKGROUND OF INVENTION

[0003] A conventional dual HVAC system for a vehicle requires two separate HVAC units, in which a front HVAC unit is dedicated to conditioning air for the front passengers and a rear HVAC unit is dedicated to conditioning air for the rear passengers. The front and rear HVAC units are contained in separate housings and each HVAC unit requires its own separate evaporator as well as heater core; therefore, a conventional dual HVAC system would require two evaporators and heater cores.

[0004] U.S. patent publication No. 2010/0273411 Al (US PAT. PUBL. '411), which is hereby incorporated by reference in its entirety, discloses a dual integrated HVAC system for an automotive vehicle. The dual integrated HVAC system includes a front HVAC unit with a front blower and a rear HVAC unit with a rear blower, whereby both the front and rear HVAC units are contained in a common housing. The front blower generates airflow through a front airflow path and the rear blower generates airflow through a rear airflow path. The dual integrated HVAC system further includes an evaporator having a first portion in the front airflow path and a second portion in the rear air flow path. A seal is situated between the front and the second portions of the evaporator to prevent air flow from leaking between the first and second portions in order to maintain separate front and rear airflow paths in the HVAC units.

[0005] It is desirable to have an elegant solution to form a seal or air barrier between the first and second portions of a heat exchanger assembly, without the need for inserting a seal into the heat exchanger core, to minimalize or eliminate airflow leaks between the first and second portions.

SUMMARY OF THE INVENTION

[0006] The invention provides for a heat exchanger assembly having a manifold and a heat exchanger core defined by a plurality of corrugated fins having louvers disposed between a plurality of tubes extending from the manifold. The corrugated fins include a plurality of closed louvers at a predetermined region along a length of the corrugated fins. The plurality of closed louvers defines a partition separating the heat exchanger core into a first portion and a second portion. The seams of the closed louvers may contain a braze alloy material to seal the closed louvers to restrict the air flow through the heat exchanger core between the first and second portions. [0007] The invention also provides for a method of manufacturing a heat exchanger assembly. The method includes the steps of providing a manifold having a plurality of tubes extending from the manifold, forming a strip of deformable material into a corrugated fins having opened louvers, crushing the louvers at a predetermined region along a length of the corrugated fins, and inserting the corrugated fins between the tubes, thereby forming a heat exchanger core. The corrugated fins are arranged such that the crushed louvers at the predetermined region along the length of the corrugated fins define a partition separating the heat exchanger core into a first portion and a second portion. The step of crushing the louvers at a predetermined region along a length of the corrugated fins is effective to close the louvers to restrict air flow through the louvers. The heat exchanger core 44 may be brazed after the step of closing the louvers 64.

[0008] An advantage of the heat exchanger assembly and method of making the same disclosed herein is that it provides a simple elegant solution of segregating the first air flow path from the second air flow path, thereby decreasing material cost and providing ease of manufacturing.

BRIEF DESCRIPTION OF DRAWINGS

[0009] This invention will be further described with reference to the accompanying drawings in which:

[0010] Fig. 1 shows an exemplary embodiment of a heat exchanger assembly of the current invention, in which the heat exchanger assembly includes a core defined by a plurality of tubes and corrugated fins having louvers. [0011] Fig. 1A is detail view of the core of the heat exchanger assembly of Fig 1, having a first portion and a second portion separated by a region of closed louvers in

predetermined locations on the corrugated fins.

[0012] Fig. 2 is side view of the heat exchanger assembly of Fig. 1 contained in a HVAC housing for a dual-integrated HVAC system.

[0013] Fig. 3 shows a perspective view of a corrugated fin having opened louvers.

[0014] Fig. 3A is a cross sectional view through line 3A-3A of the corrugated fin of Fig.

3 showing a series of open louvers.

[0015] Fig. 4 shows a die closing the louvers of the corrugated fins of Fig. 3 at a predetermined location along the length of the fins.

[0016] Fig. 4A is a cross sectional view through line 4A-4A of the corrugated fin of Fig.

4 showing a series of closed louvers.

[0017] Fig. 5 is detailed picture of the louvers closed and sealed after brazing, thereby forming an air barrier.

DETAILED DESCRIPTION OF INVENTION

[0018] Referring to the Figures 1 through 5, wherein like numerals indicate

corresponding parts throughout the several views, is an exemplary embodiment of a heat exchanger assembly 20 having a heat exchanger core 44 separated into a first portion 68 and a second portion 70 by a region of closed louvers 64 in predetermined locations along the length of the fins 42. While the exemplary embodiment shown includes two spaced apart manifolds 22, 30 having a core 44 defined by flat tubes 34 and fins 42 between the manifolds 22,30, it is to be understood that the embodiment is provided by way of example only. Alternative embodiments may include those of plate type heat exchangers having tubes 34 formed of stacked plates and fins 42 inserted between adjacent tubes 34.

[0019] Shown in Fig. 1 is the exemplary heat exchanger assembly 20 having a first manifold 22 extending along a manifold 22 A-axis. The heat exchanger assembly 20 also includes a second manifold 30 extending in a spaced and substantially parallel relationship with the first manifold 22. The first and second manifolds 22, 30 present a plurality of corresponding tube slots 32 spaced along the respective manifolds 22, 30. A plurality of fluid tubes 34, each having a length (L) and opposite open ends 36, are inserted into the corresponding tube slots 32 of the manifolds 22 for hydraulic communication between the manifolds 22, 30. Best shown in Fig. 2, each of the fluid tubes 34 include a front edge 38 oriented toward the oncoming air flow and an opposite trailing edge 40 spaced from the front edge 38. Referring back to Fig. 1, a plurality of corrugated fins 42 is inserted between adjacent fluid tubes 34 for increased heat transfer efficiency between the fluid in the tubes 34 and a stream of ambient air flowing pass the tubes 34 and fins 42. The plurality of tubes 34 and corrugated fins 42 therebetween defines the heat exchanger core 44. Best shown in Figs. 1A and 2, the exterior surfaces 46 of the tubes 34 together with the surfaces 48 of the corrugated fins 42 therebetween define a plurality of air flow channels 50 for airflow from the front edges 38 to the trailing edges 40 of the tubes 34. The manifolds 22, 30, tubes 34, and fins 42, may be assembled into a heat exchanger assembly 20 and brazed by any known methods in the art to provide a solid liquid tight heat exchanger assembly 20. [0020] The corrugated fins 42 may be formed from a continuous strip of heat conductive material, such as aluminum. Shown in Fig. 1A is a detailed segment of a portion of corrugated air fins 42 having alternating ridges 52 connected by legs 54. The alternating ridges 52 are in contact with and brazed to the surfaces 46 of adjacent fluid tubes 34. Louvers 64 are formed into the legs 54 of the fins 42 by cutting dies as the strip of heat conductive materials is being folded into corrugated air fins 42 by roller dies or by other means known in the art. The louvers 64 increases heat transfer efficiency by creating turbulence as the air flow travels from the front edge 38 of the tube to the trailing edge 40 in the air flow channels 50. The louvers 64 may also direct air flow from one air flow channel 50 to adjacent air flow channels 50 through the heat exchanger core 44 in a direction along the length (L) of the fluid tubes 34.

[0021] For use in an integrated a dual-integrated HVAC system, it is desirable to partition the heat exchanger core 44 into a first portion 68 and a second portion 70 such that air flow does not leak from one portion to the other. As shown in Fig. 2, the heat exchanger assembly 20 is disposed in a HVAC module within a duel-integrated HVAC system. The HVAC module includes a HVAC housing 58 in sealing engagement with the first and second manifolds 22, 30. The HVAC housing 58 also includes a divider wall 60 having divider wall portion 62 in sealing engagement with the heat exchanger core 44, such that the first portion 68 of the heater core 44 is in the path of the first air flow path 72 and the second portion 70 is in the path of the second air flow path 74.

[0022] Referring to Figs. 1 through 3 A, the open louvers 64 in the legs 54 of the corrugated fins 42 at the partition 66 between the first and second portions 68, 70 allow air flow or leakage through the heat exchanger core 44 in the direction along the lengths (L) of the tubes 34. This is undesirable, because air flow through the first portion 68 of the heat exchanger core 44 may leak through the open louvers 64 into the second portion 70, thereby comingling the first and second air flow paths 72, 74. To prevent air leakage across the core 44 of the heat exchanger assembly 20 in the direction along the lengths (L) of the tubes 34, the louvers 64 of the corrugated fins 42 at the partition 66 between the first and second portions 68, 70 may be sealed to form an airflow barrier.

[0023] The louvers 64 may be sealed by injecting an epoxy sealant material into the flow channels 50, inserting a plug into the air channels 50, or closing the louvers 64 by mechanical means. Injecting an epoxy sealant material into the flow channels 50 or inserting a plug into the air channels 50 is not desirable because it requires additional material and labor, as well as potentially damaging core 44. The desired alternative is to close the opened louvers 64. It is beneficial to close the louvers 64 prior to brazing the heat exchanger assembly 20. During the brazing operation, due to capillary forces, the braze alloy material 80 wicks into the seams 76 defined by the closed louvers 64 and solidifies upon cooling to form an air tight seal as shown in Fig. 5. The louvers 64 may be closed manually at predetermined locations along the length (L) of the corrugated fins 42 by using a clamping tool, such as a needle nose plier, by a set of rolling dies 78 as shown in Fig. 4, or by a pair of opposing stamping dies prior to inserting the corrugated fins 42 between the tubes 34. Shown in Fig. 4A is a leg 54 of a portion of the fins 42 having closed louvers 64. The desired location to close the louvers 64 along the length (L) of the corrugated fins 42 is determined by the desired location of the partition 66 between the first and second portions 68, 70. [0024] In other words, the louvers 64 of the fins 42 may be closed prior to assembly, in which once assembled, the close louvers 64 portion along the corrugated fins 42 defines the partition 66 between the first and second portions 68, 70. The braze alloy material 80 may be provided by cladding on the fins 42 or fluid tubes 34. Once the louvers 64 are closed, the seams 76 defined by the closed louvers 64 draws in the flowing braze alloy material 80 by capillary forces during the brazing process and, once cooled, the braze alloy material 80 forms a substantially air-tight barrier between the first and second portions 68, 70 of the core 44. It should be noted that the barrier need not be a hermetic seal, but substantially air-tight such that any air leakage between the first and second portions 68, 70 does not adversely impact the desired conditioning of the respective air flows in the first and second air flow paths 72, 74.

[0025] An alternative to closing opened louvers 64 is not to form the louvers 64 in the predetermined location during the step of forming the fins 42. A design of the fin forming tools is such that conventional louvers 64 are formed in all the convolutions except those in the area of the partition 66, where the fins 42 are void of louvers. The corrugated fins 42 are oriented such that the region void of louvers are lined up across the heat exchanger core 44 then assembled with the tubes 34 and brazed in the normal manner.

[0026] An advantage of the heat exchanger assembly 20 and method of making the same disclosed herein is that it provides a simple elegant solution of segregating the first air flow path 72 from the second air flow path 74. Other advantages include decreased materials required and ease of manufacturing. [0027] While a specific embodiment of the invention have been described and illustrated, it is to be understood that the embodiment is provided by way of example only and that the invention is not to be construed as being limited but only by proper scope of the following claims.

Claims

CLAIMS Having described the invention, it is claimed:

1. A method of manufacturing a heat exchanger assembly 20, comprising the steps of:

providing a manifold 22 having a plurality of tubes 34 extending from said manifold 22;

roll forming a strip of deformable material into corrugated fins 42 having opened louvers 64;

crushing said louvers 64 at a predetermined region along a length of said corrugated fins 42; and

inserting said corrugated fins 42 between said tubes 34 thereby forming a heat exchanger core 44,

wherein said corrugated fins 42 are arranged such that said crushed louvers 64 at the predetermined region along the length of said corrugated fins 42 defines a partition 66 separating said heat exchanger core 44 into a first portion 68 and a second portion 70.

2. The method of manufacturing a heat exchanger of claim 1,

wherein said step of crushing said louvers 64 at a predetermined region along the length of said corrugated fins 42 is effective to close said louvers 64 to restrict air flow through said louvers 64.

3. The method of manufacturing a heat exchanger of claim 2, wherein said closed louvers 64 defines an air flow barrier between said first portion 68 and said second portion 70.

4. The method of manufacturing a heat exchanger of claim 3,

further comprising the step of brazing said heat exchanger core 44 after said step of closing said louvers 64.

5. The method of manufacturing a heat exchanger of claim 4, wherein one of said plurality of tube and said plurality of fins 42 includes a surface cladding comprising a braze alloy material 80.

6. The method of manufacturing a heat exchanger of claim 5,

wherein said step of crushing said louvers 64 at a predetermined region along a length of said corrugated fins 42 is effective to close said louvers 64 such that a louver seam 76 is defined, and

wherein said step of the step of brazing said heat exchanger core 44 includes heating treating said heat exchanger core 44 a temperature and time effective to flow said braze alloy material 80 into said louver seams 76, thereby providing a sufficiently air tight seal.

7. The method of manufacturing a heat exchanger of claim 2, wherein the step of crushing said louvers 64 is completed with a pinching tool.

8. The method of manufacturing a heat exchanger of claim 2, wherein the step of crushing said louvers 64 is performed with a die after said step of forming a strip of deformable material into a corrugated fins 42 having opened louvers 64 .

9. The method of manufacturing a heat exchanger of claim 6, wherein said plurality of tubes 34 are spaced apart and extends from said manifold 22 in a parallel arrangement.

10. A heat exchanger assembly 20 comprising,

a manifold 22;

a plurality of tubes 34 extending from said manifold 22;

a plurality of corrugated fins 42 having louvers 64 disposed between said tubes 34, thereby defining a heat exchanger core 44;

wherein said corrugated fins 42 includes a plurality of closed louvers 64 at a predetermined region along a length of said corrugated fins 42, whereby said plurality of closed louvers 64 defines a partition 66 separating said heat exchanger core 44 into a first portion 68 and a second portion 70.

11. The heat exchanger assembly 20 of claim 10, wherein said plurality of closed louvers 64 sufficiently restrict air flow such that said plurality of closed louvers 64 provides an air flow barrier between said first portion 68 and said second portion 70 of heat exchanger core 44.

12. The heat exchanger assembly 20 of claim 11, wherein at least one of said closed louvers 64 defined a seam 76, and wherein said seam 76 is sealed with a braze alloy material.

13. The heat exchanger assembly 20 of claim 11, wherein said plurality of tubes 34 are spaced apart and extends from said manifold 22 in a parallel arrangement.

14. A method of manufacturing a heat exchanger assembly 20, comprising the steps of:

forming a strip of deformable material into corrugated fins 42 having louvers at predetermined regions and void of louvers at other

predetermined regions;

wherein said corrugated fins 42 are arranged such that said other predetermined region along the length of said corrugated fins 42 being void of louvers defines a partition 66 separating said heat exchanger core 44 into a first portion 68 and a second portion 70.