Heat exchanger with partial housing

Abstract

A heat exchanger, including a coolant inlet, a coolant outlet, and flat tubes consisting of two joined parts having broad and narrow sides, the joined parts being stacked on top of one another and joined along their edges to form channels therebetween for flow of gas cooled by coolant flowing through channels between the flat tubes. A partial housing includes a first side, a second side, and a joining side between the first and second sides, with the flat tubes being arranged in the partial housing. The joining side of the housing has at least one cut-out with at least one joining strip between the first and second sides, with one of the inlet and outlet in the joining strip.

Description

CROSS REFERENCE TO RELATED APPLICATION(S)

Not applicable.

STATEMENT REGARDING

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

TECHNICAL FIELD

The present invention relates to a heat exchanger, and more particularly heat exchangers having stacked two-part flat tubes for gas flow and coolant flow between the tubes.

BACKGROUND OF THE INVENTION AND TECHNICAL PROBLEMS POSED BY THE PRIOR ART

A heat exchanger was described in European Patent Application with Application No. EP 04 019 339.3 (which not published as of the priority filing date of this application), concerning an exhaust gas heat exchanger which should have a bypass. EP patent application number 04026647.0 (also not then published) discloses a heat exchanger with a partial housing, wherein the flat tubes consist in most cases of welded or drawn tubes. The heat exchanger described there is particularly disadvantageous when the flat tube is in each case formed of two parts, due to limited accessibility to the connecting seams for the purpose of preparing for the necessary soldering operation (e.g., to apply soldering materials). This is also true, though to a lesser degree, with heat exchangers which have flat tubes made of one piece.

The present invention is directed toward overcoming one or more of the problems set forth above.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a heat exchanger is provided, including a coolant inlet, a coolant outlet, and flat tubes consisting of two joined parts having broad and narrow sides, the joined parts being stacked on top of one another and joined along their edges to form channels therebetween for flow of gas cooled by coolant flowing through channels between the flat tubes. A partial housing includes a first side, a second side, and a joining side between the first and second sides, with the flat tubes being arranged in the partial housing. The joining side of the housing has at least one cut-out with at least one joining strip between the first and second sides, with one of the inlet and outlet in the joining strip.

In one form of this aspect of the present invention, there are two joining strips between the first and second sides, and the inlet is in one of the joining strips and the outlet is in the other of the joining strips.

In another form of this aspect of the present invention, at least one cut-out in the joining side extends to the first and second side.

In still another form of this aspect of the present invention, the joining strip joins the first and second sides together.

In yet another form of this aspect of the present invention, an inlet collecting tank is on one side of the flat tubes and an outlet collecting tank is on the opposite side of the flat tubes whereby gas flowing in the flat tubes flows in one direction. In an alternate form, a flow separator in the flat tubes defines a U-shape for the gas channels in the flat tubes, and inlet and outlet collecting tanks are on one end of the flat tubes.

According to another form of this aspect of the present invention, the two parts of the flat tubes have a raised shaped edging with a gap at least at two positions. In one further form, the two parts of the flat tubes are joined at joints along the raised edging, and the gaps at each position are stacked in alignment with each other. In another further form, the joining strips contain the inlet and the outlet and are aligned with the gaps in the raised formed edging, the inlet and outlet being in hydraulic connection with the coolant channels formed in the raised formed edging.

According to still another form of this aspect of the present invention, beads are on opposite edges of joining strips, and encompass the joining edge formed by the two parts of the flat tubes.

According to yet another form of this aspect of the present invention, the flat tubes are curved in the direction of flow of the gas.

In yet another form of this aspect of the present invention, the heat exchanger has a curved shape with a gas inlet on one side and a gas outlet on the opposite side.

In another aspect of the present invention, a heat exchanger is provided, including a coolant inlet, a coolant outlet, and flat tubes consisting of two joined parts having broad and narrow sides, the joined parts being stacked on top of one another and joined along their edges to form channels therebetween for flow of gas cooled by coolant flowing through channels between the flat tubes. A partial housing includes a first side, a second side, and a joining side between the first and second sides, with the flat tubes being arranged in the partial housing. The joining side of the housing has at least one single piece joining strip between the first and second sides, with one of the inlet and outlet in the joining strip.

In one form of this aspect of the present invention, the joining strips join the first and second sides together.

In another form of this aspect of the present invention, a flow separator in the flat tubes defines a U-shape for the gas channels in the flat tubes, and inlet and outlet collecting tanks are on one end of the flat tubes.

In another form of this aspect of the present invention, the two parts of the flat tubes have a raised shaped edging with a gap at least at two positions. In one further form, the two parts of the flat tubes are joined at joints along the raised edging, and the gaps at each position are stacked in alignment with each other. In another further form, the joining strips contain the inlet and the outlet and are aligned with the gaps in the raised formed edging, the inlet and outlet being in hydraulic connection with the coolant channels formed in the raised formed edging.

In still another form of this aspect of the present invention, beads are on opposite edges of joining strips, and encompass the joining edge formed by the two parts of the flat tubes.

In yet another form of this aspect of the present invention, the heat exchanger has a curved shape with a gas inlet on one side and a gas outlet on the opposite side.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a heat exchanger incorporating a first embodiment of the present invention;

FIG. 2 is a top view of the heat exchanger of FIG. 1;

FIG. 3 is perspective view of a heat exchanger according the first embodiment of the present invention;

FIG. 4 is a perspective view of another heat exchanger according the first embodiment of the present invention;

FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. 4; and

FIGS. 6-15 are perspective views and sectional representations of heat exchangers incorporating a second embodiment of the present invention, wherein:

FIGS. 6-8 are perspective views of heat exchangers having various curvatures and incorporating the present invention,

FIG. 9 is an exploded perspective view of a curved heat exchanger incorporating the present invention, and

FIGS. 10-15 are cross-sectional views of various heat exchangers incorporating the second embodiment, where:

FIGS. 10-12 are cross-sectional views located at lines 10-10 to 12-12 respectively, and

FIGS. 13-15 are perspective views through a cross-section of FIG. 9 illustrating different tubes, where FIG. 13 is at line 13-13 and FIGS. 14-15 are at line 14-14.

DETAILED DESCRIPTION OF THE INVENTION

The embodiments illustrated in the Figures relate to an exhaust gas heat exchanger cooled with the cooling fluid of an internal combustion engine, or to a charge air cooler of a motor vehicle, which may, for example, be suitably incorporated into an exhaust gas recycle system or into a combustion air intake system as will be recognized.

In the disclosed embodiments, only three or four flat tubes 20 are illustrated as stacked on top of one another, but it should be appreciated that the number of flat tubes 20 may be different than illustrated, and can be chosen, for example, dependent on the requirements for the particular intended application.

FIGS. 1-5 illustrate a first embodiment, in which the joining strips 22 are made in one piece with the first side 24 and second side 26, as can be seen especially clearly in FIG. 1. The first and second sides 24, 26 and the joining strips 22 form a partial housing which encompasses only a part of the periphery of the stack of flat tubes 20, whereby the encompassed part is approximately three sides of the periphery but at least more than 50% to about 90% of the total periphery.

The first and second sides 24, 26 extend preferably in the direction of the broad sides of the flat tubes 20 and are joined with the broad sides of the outer (e.g., top and bottom) flat tubes 20 of the stack. However, it could also be within the scope of the present invention to provide the sides or legs extending in the direction of the narrow sides of the flat tubes, in which case the joint can be made on the narrow side of a flat tube.

Also, it should be appreciated that, depending on the application, a bypass may also be provided if desired in the part of the periphery of the stack of flat tubes 20 that is not encompassed by the partial housing.

Two joining strips 22 are provided in the illustrated embodiment, with an inlet 30 located in one of the joining strips 22 and an outlet 32 in the other one (e.g., for the coolant of a motor vehicle engine, not shown).

A large central cut-out 34 is between the two joining strips 22 which at the same time, represent the joining side 36. Since the joining strips 22 are not located exactly at the front or back end, a cut out 34 can also be considered to be to the left and to the right of the two joining strips 22.

The function of the partial housing may also be accomplished by an additional part between the flat tubes, the construction of which would be further simplified because such a partial housing can, roughly speaking, be viewed as a sheet with two parallel borders. The flat tubes can also be significantly simpler to insert or mount into such a partial housing. Further, as a result of at least one cut-out in the sides of the partial housing to be bonded, the weight of the heat exchanger is also further reduced.

FIGS. 1-3 show heat exchangers in which the exhaust gas or the charge air flows in a U-shape through the flat tubes 20, as illustrated by the dashed arrows, pointing in opposite directions (on the right in FIG. 2 and the left in FIG. 3). In FIG. 2, the separation of the flat tubes 20 in the longitudinal direction is illustrated by a single dotted line which can be effected, for example, by an inserted separating spacer 38 such as illustrated in FIG. 15 (which will be explained later), or by the corresponding deformation of the flat tube 20 or flat tube parts 40, 42.

The tubes 20 may also include an internal insert (not shown) in the form of a corrugated sheet such as is known generally in the art, where the corrugations may form discrete flow passages for the gas.

FIG. 4, in contrast, illustrates a heat exchanger in which flow of exhaust gas or charge air through the flat tubes 20 is in a single direction (in FIG. 4, from left to right).

A suitable inlet and suitable outlet for the exhaust gas or charge air, such as inlet and outlet collecting tanks 50, 52, are also provided.

The heat exchanger of FIG. 3 differs from the embodiments of FIGS. 1 and 4 in that the upper flat tube parts 40 are pulled out in a cup-like manner in FIG. 3, with the lower tube parts 42 comparatively flat (and thus the two tube parts 40 and 42 are not identical. In FIG. 4, by contrast, the two tube parts 40 and 42 are identical, with the joining edge or strip 56 of the two parts running at about the same height of the flat tubes 20 (as is also the case in FIG. 5).

FIGS. 6-15 illustrate an alternative embodiment wherein the joining strips 22 are made as single parts and are attached between the first and second tube sides 24, 26. With this embodiment, heat exchangers with a curved shape, as shown in FIGS. 6-9, can be produced or manufactured more simply. The partial housing can be manufactured simply for heat exchangers with a curved shape, and in particular more simply than in the prior art in which the entire connecting side would have to be provided with a curved contour. Moreover, heat exchangers having this and other irregular shapes are frequently desirable and advantageous, for example, to allow for compact arrangement in the engine compartment of motor vehicles. This embodiment also is advantageous in that the inlet 30 and outlet 32 located on opposite sides of the heat exchanger (as can be seen in FIG. 7, which shows a heat exchanger with an undulating contour) can be manufactured more simply.

In FIGS. 6, 8 and 9, the joining strips 22 are arranged on the same side of the heat exchanger. In FIG. 6, the joining strips 22 with inlet 30 or outlet 32 are on the inward-pointing side, whereas in FIGS. 8 and 9 they are on the outward-pointing side. Since these heat exchangers have a circular arc-like contour, “inward pointing” in this connection indicates pointing to the center of the imaginary circle and “outward pointing” indicates pointing away from the center of the imaginary circle.

The two above described embodiments mentioned include flat tubes 20 composed of two flat tube parts 40 and 42. The flat tube parts 40, 42 have a raised edging 60, which can be seen, for example, in FIG. 1, which provides a view of the flat tube part 40 positioned above. The raised edging 60 is interrupted in two positions which can be designated simply as a gap 64 in the raised part of the edging (see FIGS. 1 and 13). The two parts 40 and 42 are assembled to a flat tube 20, where the two parts 40, 42 lie against one another with their joining edges 56, which are bent pointing outward in the practical example. In the practical examples, brackets 66 (see FIGS. 14 and 15) are provided at the joining edges 56, which can be bent so that the tube parts 40 and 42 will remain stable in their position with respect to one another, whereby outstanding soldering of the joints 68 can later be produced. The flat tubes 20 formed in this way are then stacked, whereby the flat tubes 20 with their raised edging 60 come to lie against one another in order to form a channel 70 for coolant in the space between two flat tubes 20. It can be seen from the depictions that the height of the raised part of the edging 60 corresponds to about half the height of the channels 70 thus formed in the practical examples illustrated here. Hereby also, the previously-mentioned gaps 64 lie on a line above one another and make possible the hydraulic joining to channels 70 in the region of the gaps 64.

It should also be recognized, however, that a raised edging 60 may also be provided on only one of the two flat tubes which always forms a channel, or on one of the flat tube parts forming a flat tube. In these cases then the height of the raised part is equal to the height of the channel 70.

The hydraulic connection is created through the specially-designed joining strips 22, which are formed with a corresponding inlet 30 or outlet 32.

Although the joining strips 22 of the two embodiments are similar to one another, it should also be recognized that there are manufacturing differences. As already mentioned, in the first described embodiment, the joining strips 22 are made in one part together with the first and second tube sides 24, 26, whereas in the second embodiment the joining strips 22 are placed as individual parts between the first and second tube sides 24, 26. Such manufacture may be readily carried out with the aid of suitable forming machines and appropriate tools (not shown).

The joining strips 22 are provided with beads 74 which each encompass two outwardly-protruding joining strips 56 of a flat tube 20. Furthermore, the joining strips 22 may be advantageously formed with projections 76 which extend in each case where two flat tubes 20 with their raised edging 60 lie against one another, in order to perfect the bending radius region that arises there, to obtain tight and lasting soldered joints (see FIGS. 5 and/or 12).

In the FIG. 12 illustrated structure, the joining strips 22 advantageously clamp together the first and second sides 24, 26, with the joining strips 22 functioning to pre-mount individual parts of the heat exchanger in order to prepare the heat exchanger more easily for soldering. However, it should be appreciated that this design is not absolutely necessary since the holding together of the individual parts can also be achieved, for example, by the collecting tanks 50, 52 which encompass the stack. Moreover, other embodiments which are not shown may also be advantageously used, with the joining strips 22 ending shortly before the edge of the first and second sides 24, 26, bound physically only to flat tube 20 or flat tube parts 40, 42. The joining strips 22 in such alternatives are thus such that they are joined either directly or indirectly with the first and second side 24, 26. In keeping with the intent of this alternative teaching, accordingly we can speak of a housing even when it consists of individual parts 24, 26, 22 which are joined either directly or indirectly.

Further possible designs of parts 40 and 42 of the flat tubes 20 are illustrated with the aid of the second embodiments, such as in FIGS. 9 and 13-15 in which the parts 40 and 42 are provided with recesses 80. Such or other recesses can also be provided, however, in connection with the first embodiment. The recesses 80 can also be replaced by suitable internal inserts in order to achieve the intended increased durability and in order to produce turbulence in the exhaust gas or in the charge air.

In the practical example illustrated in FIG. 15, the flat tubes 20 have two separated passages 84, with the separation achieved by a separating divider or spacer 38 which may be integral with, or introduced into, the flat tubes 20 (which, as mentioned already above, is also possible with continuous recesses 80).

FIG. 11 illustrates a longitudinal cross-section in the region of an inlet 30 or outlet 32 for charge air or exhaust gas of a further feature which may be advantageously incorporated with the present invention. The flat tube parts 40, 42 are provided with a shaped part 86 in this region, which represents the front ends of parts 40 and 42, for optimizing the flow of the entering charge air or exhaust gas efficiently. The shaped part 86 is attached directly to the raised edging 60 and a piece of it protrudes into inlet 30.

It should also be recognized that although the above proposals were described in combination with two-part flat tubes, the invention may also be achieved in a product with one-part flat tubes, such as those described and shown in the above-mentioned state of the art. Moreover, it should further be recognized that both described embodiments contribute to the provision of heat exchangers with high-quality solder joints which can be made because they provide ready accessibility to the soldered seams and thus permit careful preparation for soldering.

Still other aspects, objects, and advantages of the present invention can be obtained from a study of the specification, the drawings, and the appended claims. It should be understood, however, that the present invention could be used in alternate forms where less than all of the objects and advantages of the present invention and preferred embodiment as described above would be obtained.

Claims

1. A heat exchanger comprising:

flat tubes consisting of two joined parts having broad and narrow sides, said joined parts being stacked on top of one another and joined along their edges to form channels therebetween for flow of gas cooled by coolant flowing through channels between the flat tubes;

a partial housing with a first side, a second side, and a joining side between said first and second sides, said flat tubes being arranged in said partial housing; and

a coolant inlet and a coolant outlet;

wherein said housing joining side has at least one cut-out with at least one joining strip between the first and second sides, with one of said inlet and outlet in said joining strip.

2. The heat exchanger of claim 1, wherein there are two joining strips between the first and second sides, and said inlet is in one of said joining strips and said outlet is in the other of said joining strips.

3. The heat exchanger of claim 1, wherein at least one cut-out in the joining side extends to the first and second side.

4. The heat exchanger of claim 1, wherein the joining strip joins the first and second sides together.

5. The heat exchanger of claim 1, further comprising an inlet collecting tank on one side of the flat tubes and an outlet collecting tank on the opposite side of the flat tubes whereby gas flowing in the flat tubes flows in one direction.

6. The heat exchanger of claim 1, further comprising a flow separator in said flat tubes defining a U-shape for the gas channels in said flat tubes, and inlet and outlet collecting tanks on one end of the flat tubes.

7. The heat exchanger of claim 1, wherein the two parts of the flat tubes have a raised shaped edging with a gap at least at two positions.

8. The heat exchanger of claim 7, wherein the two parts of the flat tubes are joined at joints along raised edging, and said gaps at each position are stacked in alignment with each other.

9. The heat exchanger of claim 7, wherein the joining strips contain the inlet and the outlet and are aligned with the gaps in the raised formed edging, said inlet and outlet being in hydraulic connection with the coolant channels formed in the raised formed edging.

10. The heat exchanger of claim 1, further comprising beads on opposite edges of joining strips, said beads encompassing the joining edge formed by the two parts of the flat tubes.

11. The heat exchanger of claim 1, wherein said flat tubes are curved in the direction of flow of the gas.

12. The heat exchanger of claim 1, wherein the heat exchanger has a curved shape with a gas inlet on one side and a gas outlet on the opposite side.

13. A heat exchanger comprising:

flat tubes consisting of two joined parts having broad and narrow sides, said joined parts being stacked on top of one another and joined along their edges to form channels therebetween for flow of gas cooled by coolant flowing through channels between the flat tubes;

a partial housing with a first side, a second side and a joining side between said first and second sides, said flat tubes being arranged in said partial housing; and

a coolant inlet and a coolant outlet;

wherein said housing joining side includes at least one single piece joining strip between the first and second sides, with one of said inlet and outlet in said joining strip.

14. The heat exchanger of claim 13, wherein the joining strips join the first and second sides together.

15. The heat exchanger of claim 13, further comprising a flow separator in said flat tubes defining a U-shape for the gas channels in said flat tubes, and inlet and outlet collecting tanks on one end of the flat tubes.

16. The heat exchanger of claim 13, wherein the two parts of the flat tubes have a raised shaped edging with a gap at least at two positions.

17. The heat exchanger of claim 16, wherein the two parts of the flat tubes are joined at joints along raised edging, and said gaps at each position are stacked in alignment with each other.

18. The heat exchanger of claim 16, wherein the joining strips contain the inlet and the outlet and are aligned with the gaps in the raised formed edging, said inlet and outlet being in hydraulic connection With the coolant channels formed in the raised formed edging.

19. The heat exchanger of claim 13, further comprising beads on opposite edges of the joining strips, said beads encompassing the joining edge formed by the two parts of the flat tubes.

20. The heat exchanger of claim 13, wherein the heat exchanger has a curved shape with a gas inlet on one side and a gas outlet on the opposite side.