Heat exchanger and method

Abstract

A heat exchanger and a method of manufacturing a heat exchanger for transferring heat energy between first and second working fluids. The heat exchanger can include a housing, a plurality of tubes extending through the housing, and a baffle integrally formed with the housing. The baffle can include one or more fingers that can extend between at least two of the plurality of tubes. The method can include forming a baffle integrally from a side of a housing and positioning the baffle such that it extends into the interior space defined by the housing.

Description

FIELD OF THE INVENTION

The present invention relates to heat exchangers and, more particularly, to an exhaust gas recirculation cooler, a method of assembling the same, and a method of operating the same.

SUMMARY

In some embodiments, the invention provides a heat exchanger for transferring heat energy between first and second working fluids. The heat exchanger can include a housing, a number of tubes extending through the housing, and a baffle integrally formed with the housing. In some embodiments, the baffle can include a finger that extends between two of the tubes.

The present invention also provides a method of manufacturing a heat exchanger for transferring heat energy between first and second working fluids that can include the acts of providing a housing having at least two sides that are connected at an angle and define an interior space, forming a finger from one side, positioning a number of tubes in the interior space, and positioning the finger between two of the tubes. The method can also include the act of providing a bypass aperture in the finger such that a working fluid can flow through the finger. In some embodiments, the method can include the act of forming a number of fingers and positioning the fingers in the interior space.

In other embodiments, the invention provides a method of manufacturing a heat exchanger that can include the acts of providing a housing having at least two sides that define an interior space, positioning a number of tubes in the interior space, forming a baffle from one side of the housing, and folding the baffle with respect to the one side of the housing into engagement with at least one of the tubes. The invention can also include the act of providing an elastic element between the baffle and the one side of the housing.

Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a portion of a heat exchanger according to some embodiments of the present invention.

FIG. 2 is an exploded perspective view of the heat exchanger shown in FIG. 1.

FIG. 3 is a perspective view of an integrated housing and baffle of the heat exchanger shown in FIG. 1.

FIG. 4 is a perspective view of an integrated housing and baffle according to other embodiments of the present invention.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.

Also, it is to be understood that phraseology and terminology used herein with reference to device or element orientation (such as, for example, terms like “central, “upper,” “lower,” “front,” “rear,” and the like) are only used to simplify description of the present invention, and do not alone indicate or imply that the device or element referred to must have a particular orientation. In addition, terms such as “first” and “second” are used herein for purposes of description and are not intended to indicate or imply relative importance or significance.

FIGS. 1-3 illustrate a heat exchanger 10 according to some embodiments of the present invention. In some embodiments, including the illustrated embodiment of FIGS. 1-3, the heat exchanger 10 can operate as an exhaust gas recirculation cooler (EGRC) and can be operated as part of the exhaust system and/or the emission system of a vehicle. In other embodiments, the heat exchanger 10 can be used in other (e.g., non-vehicular) applications, such as, for example, in electronics cooling, industrial equipment, building heating and air-conditioning, and the like. In addition, it should be appreciated that the heat exchanger 10 of the present invention can take many forms, utilize a wide range of materials, and can be incorporated into various other systems.

During operation and as explained in greater detail below, the heat exchanger 10 can transfer heat energy from a high temperature first working fluid (e.g., exhaust gas, water, engine coolant, CO₂, an organic refrigerant, R12, R245fa, R22, R410A, air, and the like) to a lower temperature second working fluid (e.g., exhaust gas, water, engine coolant, CO₂, an organic refrigerant, R12, R245fa, R22, R410A, air, and the like). In addition, while reference is made herein to transferring heat energy between two working fluids, in some embodiments of the present invention, the heat exchanger 10 can operate to transfer heat energy between three or more fluids. Alternatively or in addition, the heat exchanger 10 can operate as a recuperator and can transfer heat energy from a high temperature portion of a heating circuit to a low temperature portion of the same heating circuit. In some such embodiments, the heat exchanger 10 can transfer heat energy from a working fluid traveling through a first portion of the heat transfer circuit to the same working fluid traveling through a second portion of the heat transfer circuit.

The heat exchanger 10 can include a housing 12 which can extend along a portion of the length of the heat exchanger 10 and can cover at least one side of the heat exchanger 10. In some embodiments, such as the illustrated embodiment of FIGS. 1-3, the housing 12 can be formed from multiple housing portions 12a, 12b having two or more sides that at least partially enclose one or more elements of the heat exchanger 10. The housing portions 12a, 12b can be formed by cutting, stamping, folding, molding, extrusion, a combination of these or other like forming processes from metals, metal alloys, composites, thermoresistive plastics, etc.

In embodiments such as the illustrated embodiment of FIGS. 1-3 in which the housing 12 includes two or more housing portions 12a, 12b, adjacent housing portions 12a, 12b can be connected together by soldering, brazing, welding, adhesive or cohesive bonding material, fasteners, integral latches or tabs, etc. In still other embodiments, two or more housing portions 12a, 12b can be at least partially connected by an interference fit. In yet other embodiments, the housing 12 can be formed from a single integral piece. Alternatively or in addition, the housing 12 can be bonded or connected to other portions of the heat exchanger 10 via soldering, brazing, welding, adhesive or cohesive bonding material, fasteners, integral latches or tabs, an interference fit, etc.

In the illustrated embodiment of FIG. 1, the heat exchanger 10 includes three flat tubes 18 supported in the housing 12. In other embodiments, the heat exchanger 10 can include one, two, four, five, six, seven, eight, or more tubes 18, each of which can have a triangular, circular, square or other polygonal, oval, or irregular cross-sectional shape.

As shown in FIGS. 1-3, the heat exchanger 10 can include at least one header 14 positioned at an end 16 of a stack of heat exchanger tubes 18. In some embodiments, the heat exchanger 10 can include multiple headers 14 which can be located at either or both ends of the stack of heat exchanger tubes 18 or at other locations on the heat exchanger 10.

As shown in FIG. 1, each of the tubes 18 can be connected to the header 14 such that a first working fluid flowing through the heat exchanger 10 is maintained separate from a second working fluid flowing through the heat exchanger 10. More specifically, the heat exchanger 10 defines a first flow path (represented by arrows 22 in FIG. 1) for the first working fluid and a second flow path (represented by arrows 24 in FIG. 1) for a second working fluid. The first and second flow paths 22, 24 are separated such that the first working fluid is prevented from entering the second flow path 24 and such that the second working fluid is prevented from entering the first flow path 22.

In some embodiments, such as the illustrated embodiment of FIGS. 1-3, the tubes 18 can be arranged in a stacking direction and can be connected to the header 14 allowing the first working fluid to travel into the open ends of the tubes 18 such that the first flow path 22 extends through at least a portion of the length of the tubes 18. In some embodiments, the second working fluid travels across an exterior of the tubes 18. For example, in the illustrated embodiment of FIGS. 1-3, the second working fluid enters the heat exchanger 10 between the header 14 and a baffle 30 and travels through the heat exchanger 10 along the second flow path 24 between adjacent tubes 18 and between the stack of tubes 18 and the housing 12.

In other embodiments, the tubes 18 can have other orientations and configurations and the first and second flow paths 22, 24 can be maintained separate by other types of dividers, inserts, partitions, and the like. In still other embodiments, the first flow path 22 can extend through some of the tubes 18 while the second flow path 24 can extend through other tubes 18.

In the illustrated embodiment of FIG. 1, the heat exchanger 10 is configured as a parallel-flow heat exchanger such that the first flow path 22 or a portion of the first flow path 22 is substantially parallel to the second flow path 24 or a portion of the second flow path 24. In other embodiments, the heat exchanger 10 can have other configurations and arrangements, such as, for example, a cross-flow or a counter-flow configuration.

In the illustrated embodiment of FIG. 1, the heat exchanger 10 is configured as a single-pass heat exchanger with the first working fluid traveling along the first flow path 22 through at least one of a number of tubes 18 and with the second working fluid traveling along the second flow path 24 between adjacent tubes 18. In other embodiments, the heat exchanger 10 can be configured as a multi-pass heat exchanger with the first working fluid traveling in a first pass through one or more of the tubes 18 and then traveling in a second pass through one or more different tubes 18 in a direction opposite to the flow direction of the first working fluid in the first pass. In these embodiments, the second working fluid can travel along the second flow path 24 between adjacent tubes 18.

In yet other embodiments, the heat exchanger 10 can be configured as a multi-pass heat exchanger with the second working fluid traveling in a first pass between a first pair of adjacent tubes 18 and then traveling in a second pass between another pair of adjacent tubes 18 in a direction opposite to the flow direction of the second working fluid in the first pass. In these embodiments, the first working fluid can travel along the first flow path 22 through at least one of the tubes 18.

In some embodiments, the heat exchanger 10 can include fluid chambers supported at one end 16 of the stake of the tubes 18, or alternatively, the heat exchanger 10 can include fluid chambers supported at both ends 16 of the stack of tubes 18. In some such embodiments, the header 14 can at least partially define a portion of one of the chambers. In embodiments having fluid chambers, a volume of the first working fluid, or alternatively a volume of the second working fluid can be housed in one of the fluid chambers.

As shown in FIGS. 1-3, the header 14 can have apertures 34 sized to receive one or more of the tubes 18. In embodiments such as the illustrated embodiment of FIGS. 1-3 having a header 14, the first working fluid flowing along the first flow path 22 can enter the tubes 18 through apertures 34 formed in the header 14. In these embodiments, the header 14 can prevent the second working fluid from entering the tubes 14. In these embodiments, the header 14 can also direct the second working fluid between adjacent tubes 18 and can prevent the second working fluid from entering the tubes 18. The header 14 can also prevent the first working fluid from flowing between the tubes 18.

In some embodiments, the heat exchanger 10 can include inserts 38 to improve heat transfer between the first and second working fluids as the first and second working fluids travel along the first and second flow paths 22, 24, respectively. As shown in FIGS. 1-3, the inserts 38 can be formed separately from and positioned within the tubes 18. Alternatively or in addition, inserts 38 can be positioned between adjacent tubes 18. In other embodiments, inserts 18 can be integrally formed with the tubes 18 and can extend outwardly from outer surfaces 40 of the tubes 18 and/or inwardly from inner surfaces 42 of the tubes 18.

In the illustrated embodiment of FIG. 1, an insert 38 is supported in each of the tubes 18, and extends along the entire length or substantially the entire length of each of the tubes 18 between opposite open ends of the tubes 18. In other embodiments, an insert 38 can be supported in only one or less than all of the tubes 18, and the insert(s) 38 can extend substantially the entire length of the tube(s) 18 between opposite ends of the tube(s) 18, or alternatively, the insert 38 can extend through the tube(s) 18 along substantially less than the entire length of the tube(s) 18. In still other embodiments, two or more inserts 38 can be supported by or in each tube 18.

In some embodiments, the inserts 38 can be secured to the tubes 18. In some such embodiments, the inserts 38 are soldered, brazed, or welded to the tubes 18. In other embodiments, the inserts 38 can be connected to the tubes 18 in another manner, such as, for example, by an interference fit, adhesive or cohesive bonding material, fasteners, etc.

In some embodiments, the ends of the tubes 18 can be press-fit into a header 14. In some such embodiments, the ends of the tubes 18 and the inserts 38 supported in the tubes 18 or between the tubes 18 can be at least partially deformed when the tubes 18 and/or the inserts 38 are press-fit into the header 14. In some such embodiments, the tubes 18 and/or the inserts 38 are pinched and maintained in compression to secure the tubes 18 and/or the inserts 38 in a desired orientation and to prevent leaking.

In the illustrated embodiment of FIGS. 1-3, the inserts 38 are formed from folded or corrugated sheets of metal. In other embodiments, the inserts 38 can be cast or molded in a desired shape and can be formed from other materials (e.g., aluminum, iron, and other metals, composite material, and the like). In still other embodiments, the inserts 38 can be cut or machined to shape in any manner, can be extruded or pressed, can be manufactured in any combination of such operations, and the like.

The heat exchanger 10 can also include one or more baffles 30 integrally formed with the housing 12 or one of the housing portions 12a, 12b. The baffles 30 can be positioned along the length of the heat exchanger 10 and can extend between two or more of the tubes 18 to direct the flow of the second working fluid along the second flow path 24 and through the housing 12. In some embodiments, the baffles 30 can extend inwardly from housing 12 into an interior of the heat exchanger 10 in order to provide structural support for the tubes 18 and/or the inserts 38. Alternatively or in addition, the baffle 30 or a portion of the baffle 30 can at least partially define the second flow path 24. As illustrated in FIGS. 1-4, the baffle 30 can be integrally formed with the housing 12 by cutting, stamping, folding, molding, extrusion, a combination of these or other like forming processes from metals, metal alloys, composites, thermoresistive plastics, etc.

Each of the baffles 30 can include one or more fingers 48, which extend inwardly into the interior of the housing 12 between adjacent tubes 18. In the illustrated embodiment of FIGS. 1-3, the fingers 48 extend into the interior of the housing in a direction substantially normal to a length of the tubes 18. In other embodiments, one or more of the fingers 48 can be oriented at acute angle with respect to the length of the tubes 18. Alternatively or in addition, the fingers 48 can be contoured to provide additional surface area to improve heat transfer and/or to generate turbulence in the second working fluid flowing past the fingers 48.

As shown in FIGS. 1-3, the number fingers 48 can be equal to the number of tubes 18 in the stack. Alternatively, one baffle 30 can include only one or two fingers 48 extending downwardly between the outermost tube(s) 18 and an interior surface of the housing 12.

In the illustrated embodiment of FIGS. 1-3, the length L of at least one of the fingers 48 is less than the width W of the tubes 18 such that the second flow path 24 extends around the outermost ends of the finger 48. In other embodiments, the length L of one or more of the fingers 48 can be substantially equal to or greater than the width W of the tubes 18. In these embodiments, openings can extend through the fingers 48, or alternatively, openings can be defined between the fingers 48 and the adjacent tubes 18 so that the second working fluid can travel along the second flow path 24 between opposite ends of the heat exchanger 10.

In some embodiments, the heat exchanger 10 can include a first baffle 30 located at one end of the heat exchanger 10 and a second baffle 30 located at the opposite end of the heat exchanger 10. In some such embodiments, the first baffle 30 can be integrally formed with the first housing portion 12a and can extend into the interior of the housing 12 from a first direction, and the second baffle 30 can be integrally formed with the second housing portion 12b and can extend into the interior of the housing 12 from a second direction. In other embodiments, both the first and second baffles 30 can be integrally formed with the first housing portion 12a and can extend into the interior of the housing 12 from a first direction, or alternatively, both the first and second baffles 30 can be integrally formed with the second housing portion 12b and can extend into the interior of the housing 12 from a second direction.

Additional baffles 30 can be positioned along the length of the heat exchanger 10 and can be integrally formed with the housing 12, or alternatively, can be secured to the housing 12. In some embodiments, additional baffles 30 are positioned between the opposite ends of the heat exchanger 10 with a first one of the additional baffles 30 having fingers 48 extending inwardly into the interior of the housing 12 from the first housing portion 12a and with a second one of the additional baffles 30 having fingers 48 extending inwardly into the interior of the housing 12 from the second housing portion 12a. In these embodiments, the baffles 30 can ensure that the second working fluid flowing along the second flow path 24 travels through the heat exchanger 10 along a circuitous or sinusoidal path around the ends of the fingers 48 of the baffles 30.

As shown in the embodiments of FIGS. 1-3, the baffles 30 can include bypass holes 50 so that a first volume of the second working fluid can travel through the baffles 30 along a generally linear path, while a second volume of the second fluid 24 travels along a circuitous around the ends of the fingers 48 of the baffles 30. The bypass holes 50 or similar apertures can be formed by drilling, punching, piercing, etching, or the like and are not limited to a particular size or shape.

FIG. 4 illustrates an alternate embodiment of the heat exchanger 210 according to the present invention. The heat exchanger 210 shown in FIG. 4 is similar in many ways to the illustrated embodiments of FIGS. 1-3 described above. Accordingly, with the exception of mutually inconsistent features and elements between the embodiment of FIG. 4 and the embodiments of FIGS. 1-3, reference is hereby made to the description above accompanying the embodiments of FIGS. 1-3 for a more complete description of the features and elements (and the alternatives to the features and elements) of the embodiment of FIG. 4. Features and elements in the embodiment of FIG. 4 corresponding to features and elements in the embodiments of FIGS. 1-3 are numbered in the 200 series.

In the illustrated embodiment of FIG. 4, the heat exchanger 210 includes a baffle 230 integrally formed with a first housing portion 212a. As shown in FIG. 4, two slits are formed along surface of the first housing portion 212a to define an elastic element 252. In the illustrated embodiment, the baffle 230 is connected to the elastic element 252 so that the baffle 230 can move along a generally linear path with respect to the first housing portion 212a in a direction substantially normal to a length of the first housing portion 212a. In some embodiments, the baffle 230 is movably connected to the housing 212 to absorb or at least partially absorb vibrations and/or expansions and contractions caused by fluctuating inlet temperatures of the first and/or second working fluids. The flexibility provided by such a connection can enhance the structural stability and reduce or eliminate thermally induced stresses, thereby improving the performance of the heat exchanger 210.

The embodiments described above and illustrated in the figures are presented by way of example only and are not intended as a limitation upon the concepts and principles of the present invention. As such, it will be appreciated by one having ordinary skill in the art that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention.

Claims

1. A heat exchanger for transferring heat energy between a first working fluid and a second working fluid, the heat exchanger comprising:

a housing having a first end and a second end;

a plurality of tubes extending through the housing between the first end and the second end and providing a flow path for the first working fluid; and

a baffle integrally formed with the housing for directing the flow of the second working fluid through the housing.

2. The heat exchanger of claim 1, wherein the baffle includes a finger extending between two of the plurality of tubes.

3. The heat exchanger of claim 2, wherein the finger defines a bypass aperture extending between a first side of the finger and a second side of the finger.

4. The heat exchanger of claim 1, wherein the baffle is moveably supported in the housing for movement relative to at least one of the plurality of tubes.

5. The heat exchanger of claim 4, wherein the baffle is movable in a direction substantially normal to a length of one of the plurality of tubes.

6. The heat exchanger of claim 1, wherein the housing is formed from a first housing portion and a second housing portion secured to the first housing portion, and wherein the baffle extends into an interior space defined between the first housing portion and the second housing portion.

7. The heat exchanger of claim 6, wherein the baffle is a first baffle and is integrally formed with the first housing portion, and further comprising a second baffle extending into the interior space from the second housing portion.

8. The heat exchanger of claim 7, wherein the second baffle is integrally formed with the second housing portion.

9. The heat exchanger of claim 6, wherein the baffle is a first baffle and is integrally formed with the first housing portion, and further comprising a second baffle integrally formed with the first housing portion and extending into the interior space.

10. The heat exchanger of claim 1, wherein the baffle is a first baffle, wherein the first baffle is adjacent to the first end of the housing, and wherein a second baffle is integrally formed with the housing adjacent to the second end of the housing.

11. A method of manufacturing a heat exchanger for transferring heat energy between a first working fluid and a second working fluid, the method comprising the acts of:

providing a housing having a first side wall and a second side wall oriented at an angle with respect to the first side wall, together the first and second side walls at least partially defining an interior space;

forming a finger from the first side wall;

positioning a plurality of tubes in the interior space; and

positioning the finger between two of the plurality of tubes.

12. The method of claim 11, wherein forming the finger from the first side wall includes forming a plurality of fingers, and wherein positioning the finger between the two of the plurality of tubes includes moving at least two of the plurality of fingers into the interior space between the plurality of tubes.

13. The method of claim 11, further comprising providing a bypass aperture in the finger such that the working fluid can flow through the finger from an inlet end of the housing toward an outlet end of the housing.

14. The method of claim 11, wherein positioning the finger between the two of the plurality of tubes includes folding the finger into the interior space between the two of the plurality of tubes.

15. The method of claim 11, wherein forming the finger from the first side wall includes cutting the first side wall.

16. The method of claim 11, further comprising moving the finger relative to the first side wall in a direction substantially normal to a longitudinal axis of one of the plurality of tubes.

17. The method of claim 11, wherein forming the finger from the first side wall includes molding the first finger.

18. A method of manufacturing a heat exchanger for transferring heat energy between a first working fluid and a second working fluid, the method comprising the acts of:

providing a generally planar housing plate;

folding the plate to define a first side wall and a second side wall oriented at an angle with respect to the first side wall such that the first and second side walls together at least partially define an interior space;

positioning a plurality of tubes in the internal space;

forming a baffle from the first side wall; and

folding the baffle with respect to the first side wall and into engagement with at least one of the plurality of tubes.

19. The method of claim 18, wherein forming the baffle from the first side wall includes cutting the first side wall.

20. The method of claim 18, further comprising piercing the baffle to provide a bypass channel through the baffle connecting an inlet side of the housing with an outlet side of the housing.

21. The method of claim 18, further comprising providing an elastic element between the baffle and the first side wall, the elastic element being deformable to allow movement of the baffle in a direction substantially normal to a flow path of the first working fluid through the housing.

22. The method of claim 18, further comprising moving the baffle relative to the first side wall in a direction substantially normal to a longitudinal axis of one of the plurality of tubes.

23. The method of claim 18, wherein forming the baffle from the first side wall includes forming a finger extending outwardly from the baffle, and wherein folding the baffle with respect to the first side wall and into engagement with the at least one of the plurality of tubes includes positioning the finger between two of the plurality of tubes.