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Title:
HEAT EXCHANGER FOR GASES, IN PARTICULAR FOR EXHAUST GASES FROM AN ENGINE, AND METHOD FOR MANUFACTURING SAME
Document Type and Number:
WIPO Patent Application WO/2018/141808
Kind Code:
A1
Abstract:
The exchanger includes: - a heat exchanger block (B) with: - a first circuit for the circulation of gases and a second circuit for the circulation of a coolant fluid that are arranged to effect a heat exchange between the gases and the coolant fluid, - a part (P) with a through-hole (h) arranged so that the gases or the coolant fluid flow therethrough, and - a tubular pipe (T) with a projection (F) that extends radially outwards from one end (Ta) thereof and that is joined to a region that surrounds the through-hole (h). The method includes the manufacture of the heat exchanger according to the present invention.

Inventors:
JIMENEZ PALACIOS, Jésus (S.A.Ctra. de Logrono, Km., 9 ZARAGOZA, 50011, ES)
ROMERO PEREZ, Raul (S.A.Ctra. de Logrono, Km., 9 ZARAGOZA, 50011, ES)
URZAY EJEA, Serafin (S.A.Ctra. de Logrono, Km., 9 ZARAGOSA, 50011, ES)
PUERTOLAS SANCHEZ, Fernando (S.A.Ctra. de Logrono, Km., 9 ZARAGOZA, 50011, ES)
Application Number:
EP2018/052430
Publication Date:
August 09, 2018
Filing Date:
January 31, 2018
Export Citation:
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Assignee:
VALEO TERMICO, S.A. (Ctra. de Logrono, Km. 89, ZARAGOZA, 50011, ES)
International Classes:
F28D7/16; F01N3/04; F28D21/00; F28F9/02
Foreign References:
FR2772875A11999-06-25
GB416201A1934-09-13
US20070175617A12007-08-02
US4026456A1977-05-31
US6899169B12005-05-31
Attorney, Agent or Firm:
METZ, Gaëlle (VALEO SYSTEMES THERMIQUES, ZA l'Agiot 8 rue Louis Lormand, CS 80517 La Verrière LE MESNIL SAINT-DENIS CEDEX, 78322, FR)
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Claims:
CLAIMS

1. Heat exchanger for gases, in particular for exhaust gases from an engine, that includes:

- a heat exchanger block (B) that includes: a first fluid circuit for the circulation of gases and a second fluid circuit for the circulation of a coolant fluid, in which the first and second fluid circuits are isolated fluidically from one another and arranged to effect a heat exchange between said gases and said coolant fluid. at least one part (P) that has a through-hole (h) traversing two respective opposing surfaces (Pa, Pb) of said at least one part (P) , in which said through-hole (h) is arranged such that said gases or said coolant fluid flow therethrough, and

- at least one tubular pipe (T) joined to said at least one part (P) such that same is in fluidic communication with said through-hole (h) , characterized in that said at least one tubular pipe (T) has at least one projection (F) that extends radially outwards from one end (Ta) of the at least one tubular pipe (T) , and in that said at least one projection (F) is joined to the at least one region of one of said two opposing surfaces (Pa, Pb) surrounding said through-hole (h) . 2. Heat exchanger according to Claim 1, in which said at least one projection (F) is a continuous perimeter flange .

3. Heat exchanger according to Claim 1, including a plurality of said at least one projections (F) that are arranged in the same plane and that extend radially outwards from different angular positions of said end (Ta) of the at least one tubular pipe (T) .

4. Heat exchanger according to any one of the preceding claims, in which the at least one surface of said at least one projection (F) that is designed to come into contact with said region of one of said two opposing surfaces (Pa, Pb) is substantially flat.

5. Heat exchanger according to any one of the preceding claims, in which at least said region of one of said two opposing surfaces (Pa, Pb) is substantially flat.

6. Heat exchanger according to any one of the preceding claims, including positioning means for positioning said at least one tubular pipe (T) in relation to said at least one part (P) , such that the at least one projection (F) is in contact with said region of one of said two opposing surfaces (Pa, Pb) and is positioned such as to enable attachment thereto, and the end (Ta) of the tubular pipe (T) from which the at least one projection (F) extends radially outwards contains the through-hole (h) .

7. Heat exchanger according to Claim 6, in which said positioning means include matching shapes that are arranged respectively on the at least one projection (F) and in an area of one of the two opposing surfaces (Pa, Pb) that is adjacent to said region, in which said matching shapes fit together to prevent the at least one tubular pipe (T) from moving in relation to the at least one part (P) along at least one plane parallel to a plane that includes said region.

8. Heat exchanger according to Claim 7, in which said matching shapes include at least one recess (R) and at least one protuberance (S) arranged respectively on the at least one projection (F) and in said area of one of the two opposing surfaces (Pa, Pb) that is adjacent to said region, or vice versa.

9. Heat exchanger according to Claim 8, in which the matching shapes include two or more recesses (R) that are distributed within a first plane and separated angularly from one another, and two or more corresponding protuberances (S) that are distributed within a second plane and separated angularly from one another, in which the recesses (R) and the protuberances (S) are arranged respectively on the at least one projection (F) and in said area of one of the two opposing surfaces (Pa, Pb) that is adjacent to said region, or vice versa.

10. Heat exchanger according to any one of the preceding claims, in which the at least one projection (F) is joined to said region of one of the two opposing surfaces (Pa, Pb) by laser welding.

11. Heat exchanger according to any one of the preceding claims, in which said at least one projection (F) is an integral part of said at least one tubular pipe (T) .

12. Heat exchanger according to any one of Claims 1 to 10, in which said at least one projection (F) is a separate element that is joined to said at least one tubular pipe (T) .

13. Heat exchanger according to any one of the preceding claims, including an inlet pipe and/or an outlet pipe for said coolant fluid, in which said at least one tubular pipe (T) is at least one of said inlet and outlet pipes for said coolant fluid, and in which said heat exchanger block (B) includes a housing (C) that contains both of said first and second fluid circuits, in which at least one wall of said housing (C) is said at least one part (P) .

14. Method for manufacturing a heat exchanger for gases according to any of the preceding claims, that involves performing the following steps sequentially: a) positioning said at least one tubular pipe (T) in relation to said at least one part (P) , such that the at least one projection (F) is in contact with said region of one of said two opposing surfaces (Pa, Pb) and is positioned such as to enable attachment thereto, and the end (Ta) of the tubular pipe (T) from which the at least one projection (F) extends radially outwards contains the through-hole (h) , and b) attaching the at least one projection (F) to said region of one of the two opposing surfaces (Pa, Pb) . 15. Method according to Claim 14, in which said step a) is performed using the positioning means according to any one of Claims 6 to 8.

16. Method according to Claim 14 or 15 in which said step b) is performed by laser welding.

Description:
DESCRIPTION

HEAT EXCHANGER FOR GASES, IN PARTICULAR FOR EXHAUST GASES FROM AN ENGINE, AND METHOD FOR MANUFACTURING SAME

Technical section

The present invention concerns, in general and in a first aspect, a heat exchanger for gases, especially exhaust gases from an engine, that includes a tubular pipe attached to a part of same, and more specifically to a heat exchanger in which the tubular pipe is designed to be attached to said part by means of a projection therefrom.

A second aspect of the invention concerns a method for manufacturing the heat exchanger according to the first aspect .

The invention is used especially in exhaust gas recirculation coolers (EGRC) of an engine.

Prior art

Heat exchangers for gases that include the characteristics of the preamble of Claim 1 of the present invention are known from the prior art, i.e. heat exchangers that include:

- a heat exchanger block that includes:

- a first fluid circuit for the circulation of gases and a second fluid circuit for the circulation of a coolant fluid, in which the first and second fluid circuits are isolated fluidically from one another and arranged to effect a heat exchange between said gases and said coolant fluid. - at least one part that has a through-hole traversing two respective opposing surfaces of said at least one part, in which said through- hole is arranged such that said gases or said coolant fluid flow therethrough, and

- at least one tubular pipe joined to said at least one part such that same is in fluidic communication with said through-hole.

In general, such tubular pipes, in particular where same are inlet or outlet pipes for coolant fluid, are attached to the housing of the heat exchanger block by cold metal transfer (CMT) welding. This welding technique requires approximately 20 seconds to weld each join.

Furthermore, the use of the CMT welding technique requires there to be a space about the tubular pipes to be welded, to enable access for the welding torch. In certain specific designs of heat exchangers, it is very difficult to obtain said space to enable access for the torch to zones close to the ends of the pipes to be welded, due to the presence of other components arranged very close to the pipes.

In such cases, it would be beneficial to use other attachment techniques that do not require such access spaces on account of being applicable more or less remotely. This is the case of the technique known as remote laser welding, which enables welding operations to be performed remotely, obviating the need for the welding system to be close to the components to be welded, since the only access space required is a space enabling access for the laser beam, which is very small. For example, it is known that, with said remote welding technique, the laser welding head can be operated at a distance of between 420 and 470 mm from the components to be welded. Most of the known designs of heat exchangers do not enable the use of such remote attachment techniques. On the other hand, there are some proposals that enable the use of laser welding to attach pipes to other parts of the heat exchanger, such as those described in patent documents DE9319731U1, EP1518043B1, DE10255978A1 and DE10359911B3.

Nonetheless, the proposals made in said patent documents have several different drawbacks, such as the need to insert the pipe into the hole in the part (DE9319731U1 ) or in a specific connector inserted therein (DE10255978A1) , or the part in the tubular pipe (EP1518043B1, where the pipe would be the housing of the heat exchanger block) , requiring substantial modifications to the part that could affect the structural strength thereof (DE10255978A1) . Furthermore, in most of said proposals, the welding involves butt joins, which results in weld joins that are not strong as would be desirable.

It therefore appears necessary to provide an alternative to the prior art that provides a heat exchanger designed to enable the use of the aforementioned remote attachment techniques and that does not suffer from the drawbacks of the known exchangers in the prior art.

Description of the invention

For this purpose, the first aspect of the present invention concerns a heat exchanger for gases, in particular for exhaust gases from an engine, that includes, in a known manner:

- a heat exchanger block that includes: - a first fluid circuit for the circulation of gases and a second fluid circuit for the circulation of a coolant fluid, in which the first and second fluid circuits are isolated fluidically from one another and arranged to effect a heat exchange between said gases and said coolant fluid.

- at least one part that has a through-hole traversing two respective opposing surfaces of said at least one part, in which said through- hole is arranged such that said gases or said coolant fluid flow therethrough, and - at least one tubular pipe joined to said at least one part such that same is in fluidic communication with said through-hole.

Unlike the heat exchangers known in the prior art, in the exchanger proposed according to the first aspect of the present invention, characteristically, the aforementioned at least one tubular pipe has at least one projection that extends radially outwards from one end of the at least one tubular pipe, and the aforementioned at least one projection is joined to a region of one of said two opposing surfaces that surrounds said through-hole.

Preferably, said join is not merely superficial but penetrates the part without passing entirely through the part .

According to a preferred example embodiment of the heat exchanger according to the first aspect of the present invention, the projection is joined to said region of one of the two opposing surfaces by laser welding, preferably remotely. The arrangement of said projection on the tubular pipe obviates the need for a butt join for said part, thereby increasing the contact zone, and therefore the join area, between the two, and is easier to access for a remote attachment system, such as one that uses the aforementioned remote welding technique.

Moreover, the projection acts as a stand for the tubular pipe on the surface of the part to which the part will be joined, before said join is carried out.

According to a preferred example embodiment, said projection is a continuous perimeter flange. Alternatively, the exchanger according to the first aspect of the present invention includes a plurality of said projections arranged in the same plane and extending radially outwards from different angular positions of said end of the tubular pipe.

Preferably, at least one surface of the projection that is designed to come into contact with said region of one of the two opposing surfaces is substantially flat. Said region of one of the two opposing surfaces is preferably substantially flat.

According to an example embodiment, the heat exchanger according to the first aspect of the present invention includes positioning means for positioning the tubular pipe in relation to said part, such that the projection is in contact with the region of one of the two opposing surfaces and is positioned such as to enable attachment thereto, and to the end of the tubular pipe from which the projection extends radially outwards includes the through-hole, i.e. covers same.

According to a variant of said example embodiment, said positioning means include matching shapes that are arranged respectively on the projection and in an area of one of the two opposing surfaces that is adjacent to said region, in which said matching shapes fit together to prevent the tubular pipe from moving in relation to the part along at least one plane parallel to a plane that includes said region.

According to an implementation of said variant, said matching shapes include at least one recess and at least one protuberance arranged respectively on the projection and in the area of one of the two opposing surfaces that is adjacent to said region, or vice versa . Advantageously, the matching shapes include two or more recesses that are distributed within a first plane and separated angularly from one another, and two or more corresponding protuberances that are distributed within a second plane and separated angularly from one another, in which the recesses and the protuberances are arranged respectively on the at least one projection and in said area of one of the two opposing surfaces that is adjacent to said region, or vice versa .

In general, the projection is an integral part of the tubular pipe, although alternatively the projection may be a separate element that is joined to the tubular pipe .

According to a preferred embodiment, the heat exchanger according to the first aspect of the present invention includes an inlet pipe and/or an outlet pipe for the coolant fluid, in which the at least one tubular pipe is at least one of said inlet and outlet pipes for the coolant fluid, and the heat exchanger block includes a housing that contains both of said first and second fluid circuits, in which at least one wall of the housing is the aforementioned at least one part. Specifically, in the aforementioned preferred example embodiment, the inlet pipe and/or the outlet pipe for the coolant fluid is attached to the outer surface of the wall (or walls, if more than one pipe is attached) of the housing as explained above, i.e. attaching the projection or projections to the region surrounding the inlet and/or outlet through-hole (or through-holes) for the coolant fluid formed in said wall (or walls) .

In the case described in the paragraph above, the tubular pipe is connected to the aforementioned second fluid circuit for the circulation of a coolant fluid. For other example embodiments, the tubular pipe is different from the tubular pipe indicated in the aforementioned preferred example embodiment, such as a pipe (or more than one pipe) that is part of either one of the aforementioned first and second fluid circuits, or a pipe connected to any one of same. For such example embodiments, the aforementioned part is a wall of the housing or of any other element that is part of the heat exchanger block (or even an element coupled thereto) .

In one of such example embodiments, the pipe is one or each pipe for carrying gases from a bundle of parallel pipes (of the first fluid circuit) and the part is a support plate attached to one end of the housing to which the aforementioned pipes for carrying gases are attached .

In another of such example embodiments, the tubular pipe is the housing itself, having a hollow cylinder or prism shape, and the part is a support plate between two of which the housing is attached by the respective opposing ends thereof. The present invention also concerns, according to a second aspect, a method for manufacturing a heat exchanger for gases according to the first aspect, that includes carrying out the following steps sequentially: a) positioning the at least one tubular pipe in relation to the at least one part, such that the at least one projection is in contact with said region of one of the two opposing surfaces and is positioned such as to enable attachment thereto, and the end of the tubular pipe from which the at least one projection extends radially outwards contains the through-hole, and b) attaching the at least one projection to the region of one of the two opposing surfaces.

According to an example embodiment of the method according to the second aspect of the present invention, the aforementioned step a) is carried out using the positioning means described above in relation to the first aspect of the present invention.

In an example embodiment of the method according to the second aspect of the present invention, the aforementioned step b) is carried out by laser welding.

Short description of the figures The aforementioned and other advantages and characteristics can be more fully understood from the following detailed description of some example embodiments with reference to the attached drawings, which are illustrative and non-limiting, in which:

Figure 1 is a perspective view showing the proposed heat exchanger according to the first aspects of the present invention for an example of embodiment in which the heat exchanger includes an inlet or outlet pipe for coolant fluid that is welded to the outer surface of a wall of the housing of the exchanger,

Figure 2 is a magnified detail of a cross section of part of Figure 1, in particular the tubular pipe and a portion of the outer wall of the housing to which same is welded,

Figures 3A and 3B are magnified views of details A and B respectively shown in Figure 2.

Detailed description of some example embodiments

The attached figures show an example embodiment of the heat exchanger for gases according to the first aspect of the invention in which said heat exchanger includes, as shown in figure 1, a heat exchanger block B that includes a housing C that contains a first fluid circuit for the circulation of gases and a second fluid circuit for the circulation of a coolant fluid, in which the first and second fluid circuits are isolated fluidically from one another and arranged to effect an exchange of heat between the gases and the coolant fluid, in which the housing C includes a wall that is the aforementioned part P that has a through-hole h (see Figures 2, 3A and 3B) that passes through two respective opposing surfaces Pa, Pb (see Figures 3A and 3B) thereof. Although not shown in the figures, the through-hole h is arranged so that, in this case, the coolant fluid flows therethrough, i.e. same is connected to the second fluid circuit. The heat exchanger block B also includes an inlet pipe T for coolant fluid (and an outlet pipe, not shown) that is joined to the wall P of the housing C such that same is in fluidic communication with the through-hole h, i.e. same is connected to the second fluid circuit. As shown in the attached figures, the tubular pipe T includes a projection F in the form of a continuous perimeter flange that extends radially outwards from one end Ta of the tubular pipe T.

Preferably, the outlet pipe for the coolant fluid (not shown) is also shaped and attached to a wall of the housing C in a manner similar to the inlet pipe, i.e. by means of a corresponding projection.

Moreover, in another example embodiment, and as an alternative or in addition to that described with reference to the inlet pipe for coolant fluid, the housing C itself is a tubular pipe that includes a projection (not shown) at one or both ends thereof, that is shaped and joined to a respective support plate J according to the present invention. The projection F is joined, preferably by laser welding, to a region of one of the two opposing surfaces Pa, Pb that surrounds the through-hole h, in particular to the outer surface Pa, although, as shown in Figures 3A and 3B, the join is not merely superficial, but the weld seam w penetrates some of the thickness of the wall P, without passing through same completely .

As shown in the attached figures, in particular Figures 3A and 3B, both the surface of the projection F that is designed to come into contact with the region of the surface Pa that surrounds the hole h and said region are substantially flat. The figures also show how the heat exchanger according to the first aspect of the present invention includes positioning means for positioning the tubular pipe T in relation to the wall P of the housing C, such that the projection F is in contact with the region of the surface Pa that surrounds the through-hole h, and is positioned such as to enable attachment thereto, and the end Ta of the tubular pipe T includes the through- hole h.

Said positioning means have, in the example embodiment shown, matching shapes that in turn have two or more recesses R that are distributed within a first plane and separated angularly from one another, and two or more corresponding protuberances S that are distributed within a second plane and separated angularly from one another, in which, as shown in Figure 1, the recesses R are arranged at different points of the perimeter edge that forms the projection F and the protuberances S in an area of the surface Pa that is adjacent to the aforementioned region to which the projection F is attached. In this case, and although Figure 1 only shows two recesses R and two respective protuberances S, there are three recesses R and three respective protuberances S (although one of each one thereof is hidden by the tubular pipe T in Figure 1), separated by an angle of 120° from one another.

Figure 3A shows how the protuberance S shown is formed by stamping, deforming a zone of the wall P. However, in other embodiments (not shown) , the protuberance S is obtained without deforming the wall P, either by adding same as an integral part of the housing when the housing C is manufactured, or in the form of a separate element attached to the wall P.

When positioning the tubular pipe T, the protuberances S fit into the recesses R such as to prevent the movement of the tubular pipe T in relation to the wall P of the housing C in a plane parallel to a plane that includes the region in which the projection F is attached, i.e. in a plane parallel to the wall P. This enables remote laser welding to be carried out without moving the tubular pipe T. However, if there is a small movement of the tubular pipe T or said pipe is not perfectly positioned (for example if there is some play between each recess R and each protuberance S) , the design of the exchanger according to the first aspect of the present invention, in particular of the projection F and of the wall P, enable said small movements or variations in the positioning of the parts to be welded to be absorbed, and as such the related attachment method can be considered to be robust.

This remote welding attachment method enables the achievement of optimum working cycles of just 2.5 seconds to fully weld each tubular pipe T to the wall P, which results in a very significant reduction in processing costs in comparison to conventional solutions . Furthermore and as shown in Figures 3A and 3B, the weld seam w completely penetrates the projection F, passing completely through same, and therefore any play between same and the surface Pa is completely absorbed, i.e. the two parts are perfectly welded, even if the surfaces in contact are not entirely flat and/or parallel .

Figures 3A and 3B show two measurements Dl and D2 relating to the width and depth of the weld seam w respectively, which are adjustable as a function of the intended design of the exchanger, in particular the mandatory technical specifications or operational requirements applicable thereto. In any case, said figures show how the weld seam w passes through the entire thickness of the projection F and some of the thickness of the wall P (approximately half in the example embodiment shown) , which ensures a very good join that is much stronger than the butt joins in the prior art . Moreover, the tubular pipe T is simpler to manufacture than standard pipes and requires the use of less material, because firstly the pipe can be shorter since there is no need for an end portion to penetrate the through-hole of the part P, and secondly because it is not the main body of the pipe but the projection F that is welded. Furthermore, the manufacture of the proposed exchanger according to the first aspect of the present invention, using the method in the second aspect, is easy to integrate into an automatic welding process, the design is less costly than conventional designs, and the cost of processing and the cost related to the working cycle is significantly lower than conventional solutions.

A person skilled in the art could make changes and modifications to the example embodiments described without thereby moving outside the scope of the invention, as defined in the attached claims.