EP3741985A1

EP3741985A1 - An exhaust gas re-circulation (egr) cooler

Info

Publication number: EP3741985A1
Application number: EP19382416.6A
Authority: EP
Inventors: Eva Tomas Herrero; Raúl ROMERO PÉREZ
Original assignee: Valeo Termico SA
Current assignee: Valeo Termico SA
Priority date: 2019-05-23
Filing date: 2019-05-23
Publication date: 2020-11-25

Abstract

A heat exchanger is disclosed in accordance with an embodiment of the present invention. The heat exchanger includes a housing formed of a first portion and a second portion that are separate from each other and that are joined to configure an enclosure to encapsulate a heat exchange core. The heat exchanger core includes a plurality of heat exchange tubes. At least one of the first portion and the second portion of the housing includes slots to receive respective ends of the heat exchange tubes.

Description

The present invention relates to a heat exchanger, particularly, to an Exhaust Gas Re-circulation (EGR) cooler for a vehicle.

Background of the invention:

An Exhaust Gas Re-circulation (EGR) system re-circulates a portion of an engine's exhaust gas back to the engine's cylinders. By re-circulating the engine's exhaust gas back to the engine's cylinder, peak in-cylinder temperatures are regulated, specifically, lowered to reduce formation of NOx gases. The exhaust gas re-circulation (EGR) system may further include a heat exchanger such as for example an Exhaust Gas Re-circulation (EGR) cooler that cools the exhaust gas before the exhaust gas is re-circulated into an intake manifold of the engine. The EGR cooler further reduces the combustion chamber temperature, thereby preventing valve clatter, detonation and further reduces NO_x formation. As a result, the Exhaust Gas Re-circulation (EGR) system substantially reduces vehicle emissions to enable meeting stringent vehicular exhaust emission norms prevalent in most parts of the world.
Referring to FIG. 1a and FIG. 1b of the accompanying drawings, a conventional heat exchanger, such as for example, an Exhaust Gas Re-circulation (EGR) cooler 01 includes a pair of spaced apart headers 02a and 02b connected to two distant and opposite end portions of a heat exchanger core 03. The heat exchanger core 03 is configured of a plurality of heat exchange elements, particularly, heat exchange tubes 03a and a plurality of fin elements 03b (not illustrated in FIGS.) lodged between the adjacent heat exchange tubes 03a. The headers 02a and 02b are configured with slots for receiving end portions of the heat exchange tubes 03a. The end portions of the heat exchange tubes 03a are joined to inside walls defining the slots configured on the headers 02a and 02b for connecting the headers 02a and 02b to the heat exchanger core 03. Such configuration facilitates distribution of first heat exchange fluid, particularly, exhaust gases to be cooled, to and collection of first heat exchange fluid from the heat exchange core 03 respectively. A Housing 04 receives second heat exchange media, particularly coolant therein and around the heat exchange tubes 03a through at least one inlet 4a. The second heat exchange media or coolant is delivered out of the housing 04 through at least one outlet 04b after the coolant has extracted heat from the first heat exchange fluid, particularly, the exhaust gases flowing through the heat exchange tubes 03a. The heat exchanger core 03 is received inside the housing 04 such that the heat exchange elements 3a in conjunction with the housing 04 configure adjacent yet separated spaces between the headers 02a and 02b for facilitating heat exchange between first heat exchanging fluid flowing inside the heat exchange tubes 03a and second heat exchange fluid flowing outside the heat exchange tubes 03a. The exhaust gas re-circulation (EGR) cooler 01 further includes a pair of heat exchanger tanks 06a and 06b, hereinafter referred to as tanks, wherein each tank 06a, 06b is joined to the corresponding header 02a and 02b for configuring a sealed connection between the headers 02a, 02b and the corresponding tanks 06a, 06b. The tanks 06a, 06b are capable of receiving first heat exchanging fluid, often pressurized heat exchanging fluid such as exhaust gases and the tanks 06a and 06b in conjunction with the corresponding headers 02a and 02b facilitate distribution of first heat exchange fluid to and collection of first heat exchange fluid from the heat exchange core 03 respectively. The tanks 06a and 06b are further connected to respective flanges 08a and 08b.
However, there are several drawbacks associated with the conventional EGR coolers. Specifically, in case of the conventional EGR coolers, the single housing 04 is connected to the separate headers 02a and 02b, such configuration involves more number of components and more number of process or assembly steps, and accordingly, higher overall cost due to higher product and process costs. As along with functional parameters such as thermal efficiency and pressure drop across the heat exchanger, for example, the EGR cooler, cost of the EGR coolers is also a crucial selection parameter considered while selecting the EGR coolers, hence, there is need for reducing the overall cost of the EGR cooler. The overall cost of the EGR cooler has two parts, i.e. product cost and process cost. The product cost is determined based on number of components required for configuring the EGR cooler, whereas the process cost is determined based on the processes and steps involved in manufacturing the EGR cooler, for example, steps involved in joining or assembling the various components configuring EGR cooler. The conventional heat exchanger, particularly, EGR cooler involves large number of components, joining and assembly steps for configuring the EGR cooler and as such the product and process costs associated with the EGR cooler are high. Accordingly, the overall cost of the EGR cooler is high. The product cost and the process cost can be reduced by reducing the number of the components or assembly steps required for configuring the EGR cooler. Accordingly, there is a need for a heat exchanger configured of comparatively fewer components than conventional heat exchangers, thereby reducing the product costs. Also, there is a need for a heat exchanger that involves comparatively fewer assembly or manufacturing steps for manufacturing thereof than conventional heat exchanger, thereby reducing the process costs.
The overall costs can further be reduced by using more standard components of predetermined size. However, in case of the conventional EGR cooler with single housing configuration, there are fewer number of standard parts used for manufacturing different configurations of EGR cooler. Each time the configuration of the EGR cooler changes, a different housing is required to be manufactured.

Description of the invention:

An object of the present invention is to provide a heat exchanger that is comparatively inexpensive than conventional heat exchangers.
Another object of the present invention is to provide a heat exchanger that is configured of comparatively fewer components than conventional heat exchangers, thereby reducing the product costs.
Still another object of the present invention is to provide a heat exchanger that eliminates certain joining and assembly processes involved in configuring the EGR cooler, thereby involves comparatively fewer manufacturing steps and lesser process costs than conventional heat exchangers.
Another object of the present invention is to use more number of standard components for configuring different EGR coolers.
Yet another object of the present invention is to provide a heat exchanger that is simple in construction, convenient to assembly and manufacture.
In the present description, some elements or parameters may be indexed, such as a first element and a second element. In this case, unless stated otherwise, this indexation is only meant to differentiate and name elements which are similar but not identical. No idea of priority should be inferred from such indexation, as these terms may be switched without betraying the invention. Additionally, this indexation does not imply any order in mounting or use of the elements of the invention.
A heat exchanger is disclosed in accordance with an embodiment of the present invention. The heat exchanger includes a housing formed of a first portion and a second portion that are separate from each other and that are joined to configure an enclosure to encapsulate a heat exchange core. The heat exchanger core includes a plurality of heat exchange tubes. At least one of the first portion and the second portion of the housing includes slots to receive respective ends of the heat exchange tubes.
Specifically, the first portion is a tubular structure that includes a closed end with slots formed thereon, an open end and side walls joining the closed end to the open end, the second portion is a tubular structure complimentary to the first portion and includes a closed end with slots formed thereon, an open end and side walls joining the closed end to the open end.
Generally, the open ends of the respective first portion and the second portion are joined by at least one of laser welding and brazing to configure the enclosure with an interface at the joint between the first portion and the second portion.
Specifically, the open ends of the respective first portion and the second portion are joined by either one of butt welding and overlap welding to configure the enclosure with the interface at the joint between the first portion and the second portion.
In a preferred embodiment of the present invention, the first portion and the second portion are identical and symmetric with respect to the interface.
Alternatively, the first portion and the second portion are different and non-symmetric with respect to the interface.
Specifically, the first portion and the second portion are formed by either one of deep drawing and stamping.
Further, at least one of the first portion and the second portion is joined to the respective tanks, the slots configured on the first portion and the second portion in conjunction with the respective tanks facilitate distribution of first heat exchange fluid to and collection of first heat exchange fluid from the heat exchange tubes respectively.
Generally, the tanks are connected to corresponding flanges.
Further, the heat exchanger includes at least one inlet and at least one outlet, the at least one inlet receives second heat exchange fluid inside the housing and around the heat exchange tubes, whereas the at least one outlet delivers second heat exchange fluid out of the housing.
In accordance with an embodiment of the present invention, the housing further includes at least one intermediate portion disposed between the first portion and the second portion and adapted to configure joint there between.
A method of assembling a heat exchanger is disclosed in accordance with an embodiment of the present invention. The method includes the steps of selecting a first portion and a separate second portion of the housing based on desired overall length of the housing. The first portion is a tubular structure that includes a closed end with slots formed thereon, an open end and side walls joining the closed end to the open end. The second portion is also a tubular structure complimentary to the first portion and includes a closed end with slots formed thereon, an open end and side walls joining the closed end to the open end. Thereafter, the first portion receives at least a portion of a plurality of heat exchange tubes of a heat exchange core and slots formed on the first portion receives first end of the heat exchange tubes. Similarly, the second portion receives remaining portion of the heat exchange tubes and slots formed on the second portion receives second end of the heat exchange tubes opposite to the first end. Thereafter, joining by at least one of brazing and laser welding, the open ends of the respective first portion and the second portion to each other, the ends of the heat exchange tubes to inside walls defining the slots respectively, tanks to the first portion and the second portion respectively, and flanges to the first tank and the second tank respectively.
Specifically, the first portion and the second portion are formed by either one of deep drawing and stamping.
Generally, the step of joining the open ends of the respective first portion and the second portion involves directly joining the open ends to each other.
Alternatively, the step of joining the open ends of the respective first portion and the second portion to each other involves disposing at least one intermediate tubular element between the first portion and the second portion and joining the ends of the intermediate portion to the first portion and the second portion respectively.
Further, the step of joining the open ends of the respective first portion and the second portion to each other, the ends of the heat exchange tubes to inside walls defining the slots respectively, the tanks to the first portion and the second portion respectively and flanges to the first tank and the second tank respectively involves arranging all components to be joined in pre-braze assembled configuration and subjecting to brazing in a brazing furnace.

Brief description of the drawings:

Other characteristics, details and advantages of the invention can be inferred from the description of the invention hereunder. A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying figures, wherein:

FIG. 1a illustrates a conventional heat exchanger, wherein housing is a single piece component, and the housing and collector plates are separate components;
FIG. 1b illustrates an exploded view of the conventional heat exchanger of FIG. 1a ;
FIG. 2 illustrates an exploded view of a heat exchanger in accordance with an embodiment of the present invention;
FIG. 3a illustrates an assembled view of the heat exchanger of FIG. 2 ;
FIG. 3b illustrates a first housing portion of the heat exchanger of FIG. 3a with slots formed on a closed end thereof;
FIG. 3c illustrates a second housing portion of the heat exchanger of FIG. 3a with slots formed on a closed end thereof;
FIG. 4a illustrates a front view of the heat exchanger of FIG. 2 ;
FIG. 4b illustrates a sectional view of the heat exchanger along section line A-A' of FIG. 4a ;
FIG. 5a illustrates a left side view of the heat exchanger of FIG. 2 ;
FIG. 5b illustrates a sectional view of the heat exchanger along section line B-B' of FIG. 5a ; and
FIG. 6 illustrates an assembled view of the heat exchanger in accordance with yet another embodiment of the present invention; and
FIG. 7 illustrates a flow chart depicting various steps involved in assembling a heat exchanger in accordance with an embodiment of the present invention.

It must be noted that the figures disclose the invention in a detailed enough way to be implemented, said figures helping to better define the invention if needs be. The invention should however not be limited to the embodiment disclosed in the description.

Detailed description of the preferred embodiments:

An Exhaust Gas Re-circulation cooler, hereinafter referred to as an EGR cooler is disclosed in accordance with an embodiment of the present invention. The EGR cooler of the present invention involves fewer components and fewer manufacturing and assembly steps as compared to a conventional EGR cooler and as such EGR cooler of the present invention is comparatively inexpensive as compared to the conventional EGR coolers. The EGR cooler includes a housing formed of a first portion and a second portion joined to configure an enclosure to encapsulate a heat exchange core. The heat exchanger core includes a plurality of heat exchange tubes and fins lodged between the heat exchange tubes. At least one portion of the housing itself includes slots that receive respective ends of the heat exchange tubes, thereby performing function of the headers and eliminating the headers. By eliminating the header, the process steps involved in configuring joint between the header and the tanks are also eliminated. Accordingly, the overall cost of the EGR cooler is reduced. The at least one of the first portion and the second portion is further connected to respective tanks. Although, the heat exchanger of the present invention is explained in the forthcoming description with example of an EGR cooler, however, present invention is not limited to EGR coolers only and is applicable to any heat exchanger used in vehicular as well as non vehicular environment.
FIG.1a illustrates an assembled view of a conventional heat exchanger, particularly an EGR cooler 01. FIG. 1b illustrates an exploded view of the conventional heat exchanger, particularly the EGR cooler 01. The conventional EGR cooler 01 includes a pair of headers or collector plates 02a and 02b, one housing 04 with an inlet 04a and an out let 04b, a pair of tanks 06a and 06b, a pair of flanges 08a and 08b and a heat exchanger core 03 formed by assembling a plurality of heat exchange tubes 03a and fins 03b lodged between the adjacent heat exchange tubes 03a. The housing 04 of the conventional EGR cooler 01 is a single piece, non-standard component and as such different size of housing 04 is used based on different configuration of the EGR cooler 01 to be formed thereby. Further, the collector plates or headers 02a and 02b are separate components that are joined to the housing 04 by any of the joining processes. Specifically, the headers 02a and 02b are joined to opposite ends of the housing 04 by any of the joining processes such as brazing or laser welding. In case the headers 02a and 02b are joined to the opposite ends of the housing 04 by laser welding, more process steps are involved. Even in case the joint between headers 02a and 02b and the opposite ends of the housing 04 is configured by brazing along with other joints by arranging all components to be joined in a pre-brazing assembled configuration and subjecting all the components to brazing inside a brazing furnace, still the headers 02a and 02b and the opposite ends of the housing 04 are required to be arranged in pre-brazing assembled configuration for configuring the brazing joint there-between. As such irrespective of the process by which the headers 02a and 02b are joined to opposite ends of the housing 04, the conventional EGR cooler requires additional process steps for configuring joint between the headers 02a and 02b and the opposite ends of the housing 04.
FIG. 2 illustrates an exploded view of a heat exchanger, particularly an EGR cooler 100 in accordance with an embodiment of the present invention. The EGR cooler 100 includes housing 10 formed of at least two separate portions 10a and 10b, a heat exchange core 20 configured of a plurality of heat exchange tubes 22 and fins 24 lodged between the adjacent heat exchange tubes 22, a pair of heat exchanger tanks 30a and 30b and a pair of flanges 40a and 40b.
The first portion 10a is a tubular structure that includes a closed end 11a with slots 12a formed thereon, an open end 13a and side walls 15a joining the closed end 11a to the open end 13a. Similarly, the second portion 10b is also a tubular structure complimentary to the first portion 10a and includes a closed end 11b with slots 12b formed thereon, an open end 13b and side walls 15b joining the closed end 11b to the open end 13b. The first portion 10a and the second portion 10b of the housing 10 are joined to configure an enclosure as illustrated in FIG. 3a . The enclosure so configured is capable of encapsulating the heat exchange core 20, particularly, the plurality of heat exchange tubes 22 and the fins 24. Specifically, the FIG. 3a illustrates an assembled view of the EGR cooler 100. More specifically, the open ends 13a and 13b of the first portion 10a and the second portion 10b respectively abut against each other and are joined together to configure the enclosure with an interface 10c at the joint between the first portion 10a and the second portion 10b. At least one of the first portion 10a and the second portion 10b of the housing 10 includes the slots 12a, 12b formed thereon. In a preferred embodiment, the portions 10a and 10b of the housing 10 include the slots 12a and 12b to receive the respective ends 22a and 22b of the heat exchange tubes 22. More specifically, the closed ends 11a and 11b of the first portion 10a and the second portion 10b configured with the slots 12a and 12b function as the collector plates. FIG 3b illustrates the first portion 10a with the slots 12a formed on the closed end 11a thereof. FIG. 3c illustrates the second housing portion 10b with the slots 12b formed on the closed end 11b thereof.
The slots 12a configured on the closed end 11a of the first portion 10a and the slots 12b configured on the closed end 11b of the second portion 10b receive the respective ends 22a and 22b of the heat exchange tubes 22. More specifically, the slots 12a and 12b configured on the closed ends 11a and 11b of the first portion 10a and the second portion 10b receive the respective ends 22a and 22b of the heat exchange tubes 22 in a spaced configuration to facilitate distribution of first heat exchange fluid to and collection of first heat exchange fluid from the heat exchange core 20 respectively. In accordance with an embodiment of the present invention, joint between the ends 22a and 22b of the heat exchange tubes 22 and inside walls defining the slots 12a and 12b is achieved by brazing. More specifically, the ends 22a and 22b of the heat exchange tubes 22 are arranged inside the slots 12a and 12b along with other components to be joined to define a pre-braze assembled configuration and subjected to brazing inside the brazing furnace for configuring brazing joint between the heat exchange tubes 22 and the walls defining the slots 12a and 12b along with brazing joint between the respective other components.
In one embodiment, the open ends 13a and 13b of the first portion 10a and the second portion 10b respectively are joined by either one of laser welding and brazing to configure the interface 10c. In accordance with another embodiment, the first portion 10a and the second portion 10b of the housing are arranged in configuration to be joined along with the other components to be joined to define pre-braze assembled configuration and subjected to brazing inside the brazing furnace for configuring brazing joint between the first portion 10a and the second portion 10b along with brazing joints between the respective other components. As such most of the components to be joined for configuring the EGR cooler 100 are joined by the single step brazing process. However, the present invention is not limited to any particular method of joining the first portion 10a to the second portion 10b.
With such configuration, the housing 10 is performing functions of two components thereby eliminating one component. More specifically, which such configuration, the housing 10 not only performs its primary function of encapsulating the heat exchange core 20 but also performs the function of the collector plates and the collector plates that are essential components of the conventional heat exchanger are no longer required. Comparing exploded views of the conventional EGR cooler 01 and the EGR cooler 100 of the present invention, it is evident that the EGR cooler 100 of the present invention requires comparatively fewer components as compared to the conventional EGR cooler 01. By elimination of the components, particularly, elimination of the collector plates, the product costs of the EGR cooler 100 is reduced. Also, with such configuration of the EGR cooler 100, the process steps required for configuring the joint between the opposite ends of the housing and the collector plates are eliminated. With such configuration, process cost savings are achieved. The housing 10 configured by joining the first portion 10a and the second portion 10b further includes at least one inlet 14a and at least one outlet 14b. The at least one inlet 14a receives second heat exchange fluid inside the housing 10 and around the heat exchange tubes 22. The at least one outlet 14b delivers second heat exchange fluid out of the housing 10. With such configuration, the first heat exchange fluid, particularly, the exhaust gases to be cooled flows inside the heat exchange tubes 22, whereas second heat exchange fluid, particularly coolant received in the housing 10 through the at least one inlet 14a flows outside the heat exchange tubes 22 to facilitate heat exchange between the first heat exchange fluid and the second heat exchange fluid. The coolant is delivered out of the housing 10 through the at least one outlet 14b after the coolant had extracted heat from the first heat exchange fluid, particularly, the exhaust gases flowing through the heat exchange tubes 22.
Generally, the open ends 13a and 13b of the first portion 10a and the second portion 10b are joined to configure the enclosure with the interface 10c by either one of butt welding and overlap welding.
In accordance with an embodiment, the first portion 10a and the second portion 10b are identical standard components. With such configuration, we can achieve standardization of the components and one single standard component can be used either as the first portion 10a or the second portion 10b, also, the hassle of manufacturing the first portion 10a and the second portion 10b in pairs of complimentary components is eliminated.
In accordance with an embodiment of the present invention, the first portion 10a and the second portion 10b are different and non-symmetric about the interface 10c. More specifically, in accordance with an embodiment of the present invention the housing 10 can be configured by joining the first portion 10a that is a standard component of a pre-determined length and a second portion 10b that is of any different dimension. The housing 10 so formed can be of different overall lengths based on different configurations of the EGR coolers as per customer requirements. In accordance with still another embodiment, the first portion 10a and the second portion 10b are identical standard components that are joined by at least one intermediate portion 10d as illustrated in FIG. 6 . The at least one intermediate portion 10d is disposed between the first portion 10a and the second portion 10b and configures joint there between. Particularly, one end of the at least one intermediate portion 10d is joined to the first portion 10a to form interface 10c between the first portion and the at least one intermediate portion 10d, whereas opposite end of the at least one intermediate portion 10d is joined to the second portion 10b to configure another interface 10c between the second portion 10b and the at least one intermediate portion 10d. The at least one intermediate portion 10d can be of different lengths based on the different overall lengths of the housing 10 required based on different configurations of the EGR coolers as per customer requirements. With such configuration of the EGR cooler 100, comparatively more number of standard parts can be used for manufacturing different configurations of EGR cooler as compared to conventional EGR cooler, thereby reducing the overall costs.
The first portion 10a and the second portion 10b are having simple profile with straight external surfaces and accordingly, the first portion 10a and the second portion 10b are formed by deep drawing. In accordance with another embodiment of the present invention, the first portion 10a and the second portion 10b are formed by stamping. The first portion 10a and the second portion 10b are formed of stainless steel or aluminum or alloy thereof.
The first portion 10a and the second portion 10b can be of any length based on the size of the EGR core to be received and encapsulated, for example, in case the thickness of the sheet from which the first portion and the second portion are configured of is 1 mm, then the length of first portion and second portion that can be configured from such sheet by stamping can be 90 mm. Considering, the first portion 10a and the second portion 10b are of same length, the total length of the housing formed by joining the first portion 10a and the second portion 10b can be 180mm that is sufficient for receiving and encapsulating the core of the EGR cooler. The first portion 10a and the second housing portion 10b can be rectangular in shape or circular in shape. However, the present invention is not limited to any particular shape or configuration of the first portion 10a and the second portion 10b of the housing 10. The present invention is not limited to whether the first portion 10a and the second portion 10b are identical in length or not or any particular method of joining the first portion 10a and the second portion 10b. The present invention is still not limited to any material of the first portion 10a and the second portion 10b. The housing 10 of the present invention formed of two separate portions 10a and 10b will still be within scope and ambit of the present invention as far as the closed ends 11a and 11b of the respective first portion 10a and the second portion 10b are configurable with the slots 12a and 12b and function as collector plates to facilitate distribution of heat exchange fluid to and collection of heat exchange fluid from the heat exchange core 20 respectively and as far as the first portion 10a and the second portion 10b are capable of being joined together to configure the enclosure for enclosing the heat exchange core 20.
FIG. 4a illustrates a front view of the heat exchanger 100. FIG. 4b illustrates a sectional view of the heat exchanger along section line A-A'. FIG. 5a illustrates a left side view of the EGR cooler 100. FIG. 5b illustrates a sectional view of the heat exchanger along section line B-B'. The closed ends 11a and 11b of the respective first portion 10a and the second portion 10b are configured with the slots 12a and 12b and function as collector plates integrally formed with the respective portions 10a and 10b of the housing 10. The slots 12a and 12b configured on at least one of the closed ends 11a and 11b receives the respective ends 22a and 22b of the heat exchange tubes 22. Preferably, the slots 12a and 12b configured on the closed ends 11a and 11b of the respective first portion 10a and the second portion 10b receive the respective ends 22a and 22b of the heat exchange tubes 22 as illustrated in FIG. 5b . The ends 22a and 22b of the heat exchange tubes 22 are joined to inside walls defining the slots 12a and 12b configured on the closed ends 11a and 11b of the corresponding first portion 10a and the second portion 10b. In accordance with an embodiment of the present invention, the ends 22a and 22b of the heat exchange tubes 22 are joined to inside walls defining the slots 12a and 12b by laser welding or brazing. However, the present invention is not limited to any particular method for configuring the joint between the ends 22a and 22b of the heat exchange tubes 22 and the inside walls of the respective slots 12a and 12b. The at least one of the first portion 10a and the second portion 10b is further connected to the respective tanks 30a and 30b. Preferably, the first portion 10a and the second portion 10b are connected to the respective tanks 30a and 30b by crimping. The slots 12a and 12b configured on the first portion 10a and the second portion 10b respectively in conjunction with the respective tanks 30a and 30b facilitate distribution of first heat exchange fluid to and collection of first heat exchange fluid from the heat exchange core 20 respectively. However, the present invention is not limited to any particular connection method for configuring joint between the first portion 10a and the second portion 10b and the respective tanks 30a and 30b as long as the connection method configures secure joint between the first and second portions 10a and 10b and the respective tanks 30a and 30b.
A method of assembling an EGR cooler 100 is disclosed in accordance with an embodiment of the present invention. FIG. 6 is a flow chart depicting various steps involved in assembling the heat exchanger 100. The method includes the steps of selecting a first portion 10a and a separate second portion 10b for configuring the housing 10 based on desired overall length of the housing 10 that in turn is based on the configuration of the heat exchanger 100. The first portion 10a is a tubular structure that includes a closed end 11a with slots 12a formed thereon, an open end 13a and side walls 15a joining the closed end 11a to the open end 13a. Similarly, the second portion 10b is a tubular structure complimentary to the first portion 10a and includes a closed end 11b with the slots 12b formed thereon, an open end 13b and side walls 15b joining the closed end 11b to the open end 13b. Thereafter, the first portion 10a receives at least a portion of a plurality of heat exchange tubes 22 of a heat exchange core 20 and the slots 12a formed on the first portion 10a receives the first end 22a of the heat exchange tubes 22. Similarly, the second portion 10b receives the remaining portion of the heat exchange tubes 22 and the slots 12b formed on the second portion 10b receives the second end 22b of the heat exchange tubes 22 opposite to the first end 22a. Thereafter, joining by either one of brazing and laser welding, the open ends 13a and 13b of the respective first portion 10a and the second portion 10b to each other, the ends 22a and 22b of the heat exchange tubes 22 to inside walls of slots 12a and 12b configured on the respective first portion 10a and the second portion 10b, tanks 30a and 30b to the first portion 10a and the second portion 10b respectively, and the flanges 40a and 40b to the first tank 30a and the second tank 30b respectively. The flange 40a facilitate connection of the EGR cooler 100 with an inlet pipe delivering exhaust gases into the EGR cooler 100. The flange 40b facilitate connection of the EGR cooler 100 with an outlet pipe receiving exhaust gases out of the EGR cooler 100 after the exhaust gases are cooled in the EGR cooler 100.
Generally, the step of joining the open ends 13a and 13b of the respective first portion 10a and the second portion 10b involves directly joining the open ends 13a and 13b to each other. Alternatively, the step of joining the open ends 13a and 13b of the respective first portion 10a and the second portion 10b to each other involves disposing at least one intermediate tubular element 10d between the first portion 10a and the second portion 10b and joining the ends of the intermediate portion 10d to the first portion 10a and the second portion 10b respectively. The intermediate tubular element 10d is complimentary to the first portion 10a and the second portion 10b and is having simple profile with straight external surfaces, accordingly, the intermediate tubular element 10d is also formed by deep drawing. In accordance with another embodiment of the present invention, the intermediate tubular element 10d is formed by stamping. The step of joining the open ends 13a and 13b of the respective first portion 10a and the second portion 10b to each other, the ends 22a and 22b of the heat exchange tubes 22 to inside walls defining the slots 12a and 12b respectively, tanks 30a and 30b to the first portion 10a and the second portion 10b respectively, and flanges 40a and 40b to the first tank 30a and the second tank 30b respectively involves arranging all components to be joined in pre-braze assembled configuration and subjecting to brazing in a brazing furnace. With such method all the components to be joined are joined in a single step brazing, thereby reducing the assembly time and effort.
Several modifications and improvement might be applied by the person skilled in the art to the EGR cooler 100 as defined above, and such modifications and improvements will still be considered within the scope and ambit of the present invention, as long as the heat exchanger includes a housing formed of a first portion and a second portion that are separate from each other and that are joined to configure an enclosure to encapsulate a heat exchange core. The heat exchanger core includes a plurality of heat exchange tubes. At least one of the first portion and the second portion of the housing includes slots formed thereon to receive respective ends of the heat exchange tubes.
In any case, the invention cannot and should not be limited to the embodiments specifically described in this document, as other embodiments might exist. The invention shall spread to any equivalent means and any technically operating combination of means.

Claims

A heat exchanger (100) comprising a housing (10) formed of a first portion (10a) and a second portion (10b) that are separate from each other and that are joined to configure an enclosure adapted to encapsulate a heat exchange core (20) comprising a plurality of heat exchange tubes (22), at least one of the first portion (10a) and the second portion (10b) of the housing (10) comprising slots (12a, 12b) adapted to receive respective ends (22a, 22b) of the heat exchange tubes (22).
The heat exchanger (100) in accordance with the previous claim, wherein the first portion (10a) is a tubular structure comprising a closed end (11a) with the slots (12a) formed thereon, an open end (13a) and side walls (15a) joining the closed end (11a) to the open end (13a), the second portion (10b) is a tubular structure complimentary to the first portion (10a) and comprising a closed end (11b) with the slots (12b) formed thereon, an open end (13b) and side walls (15b) joining the closed end (11b) to the open end (13b).
The heat exchanger (100) in accordance with claim 2, wherein the open ends (13a) and (13b) of the respective first portion (10a) and the second portion (10b) are joined by at least one of laser welding and brazing to configure the enclosure with an interface (10c) at the joint between the first portion (10a) and the second portion (10b).
The heat exchanger (100) in accordance with any of the preceding claims, wherein the open ends (13a, 13b) of the respective first portion (10a) and the second portion (10b) are joined by either one of butt welding and overlap welding to configure the enclosure with the interface (10c) at the joint between the first portion (10a) and the second portion (10b).
The heat exchanger (100) in accordance with claim 3, wherein the first portion (10a) and the second portion (10b) are identical and symmetric with respect to the interface (10c).
The heat exchanger (100) in accordance with the claim 3, wherein the first portion (10a) and the second portion (10b) are different and non-symmetric with respect to the interface (10c).
The heat exchanger (100) in accordance with any of the preceding claims, wherein the first portion (10a) and the second portion (10b) are formed by either one of deep drawing and stamping.
The heat exchanger (100) in accordance with any of the preceding claims, wherein at least one of the first portion (10a) and the second portion (10b) is adapted to be joined to the respective tanks (30a) and (30b), the slots (12a) and (12b) configured on the first portion (10a) and the second portion (10b) in conjunction with the respective tanks (30a,30b) are adapted to facilitate distribution of first heat exchange fluid to and collection of first heat exchange fluid from the heat exchange tubes (22) respectively.
The heat exchanger (100) in accordance with any of the preceding claims, wherein the tanks (30a, 30b) are connected to corresponding flanges (40a, 40b).
The heat exchanger (100) in accordance with any of the preceding claims, further comprising at least one inlet (14a) and at least one outlet (14b), the at least one inlet (14a) is adapted to receive second heat exchange fluid inside the housing (10) and around the heat exchange tubes (22) whereas the at least one outlet (14b) is adapted to deliver second heat exchange fluid out of the housing (10).
The heat exchanger (100) in accordance with any of the preceding claims, wherein the housing further comprises at least one intermediate portion (10d) disposed between the first portion (10a) and the second portion (10b) and adapted to configure joint there between.
A method for assembling a heat exchanger (100) comprising the steps of:
• selecting a first portion (10a) and a separate second portion (10b) for configuring the housing (10) based on desired overall length of the housing (10), wherein the first portion (10a) is a tubular structure comprising a closed end (11a) with slots (12a) formed thereon, an open end (13a) and side walls (15a) joining the closed end (11a) to the open end (13a), the second portion (10b) is also a tubular structure complimentary to the first portion (10a) and comprising a closed end (11b) with slots (12b) formed thereon, an open end (13b) and side walls (15b) joining the closed end (11b) to the open end (13b);

• receiving at least a portion of a plurality of heat exchange tubes (22) of a heat exchange core (20) within the first portion (10a) and receiving the first end (22a) of the heat exchange tubes (22) in the slots (12a) formed on the first portion (10a);

• receiving the remaining portion of the heat exchange tubes (22) in the second portion (10b) and receiving the second end (22b) of the heat exchange tubes (22) opposite to the first end (22a) in the slots (12b) formed on the second portion (10b);

• joining by at least one of brazing and laser welding, the open ends (13a) and (13b) of the respective first portion (10a) and the second portion (10b) to each other, the ends (22a) and (22b) of the heat exchange tubes (22) to inside walls defining the slots (12a) and (12b) respectively, tanks (30a) and (30b) to the first portion (10a) and the second portion (10b) respectively, and flanges (40a) and (40b) to the first tank (30a) and the second tank (30b) respectively.
The method of assembling as claimed in the previous claim, wherein the first portion (10a) and the second portion (10b) are formed by either one of deep drawing and stamping.
The method of assembling as claimed in the previous claim, wherein the step of joining the open ends (13a) and (13b) of the respective first portion (10a) and the second portion (10b) involves directly joining the open ends (13a) and (13b) to each other.
The method of assembling as claimed in the previous claim, wherein the step of joining the open ends (13a) and (13b) of the respective first portion (10a) and the second portion (10b) to each other involves disposing at least one intermediate tubular element (10d) between the first portion (10a) and the second portion (10b) and joining the ends of the intermediate portion (10d) to the first portion (10a) and the second portion (10b) respectively.
The method of assembling as claimed in the previous claim, wherein the step of joining the open ends (13a) and (13b) of the respective first portion (10a) and the second portion (10b) to each other, the ends (22a) and (22b) of the heat exchange tubes (22) to inside walls defining the slots (12a) and (12b) respectively, tanks (30a) and (30b) to the first portion (10a) and the second portion (10b) respectively, and flanges (40a) and (40b) to the first tank (30a) and the second tank (30b) respectively involves arranging all components to be joined in pre-braze assembled configuration and subjecting to brazing in a brazing furnace.