Composite exhaust gas recirculation cooler

Abstract

A cooler having a first component made of at least one of steel, stainless steel, plastic and ceramic. A second component may be made of aluminum, wherein the two components may be connected to each other in a connecting area via a friction stir weld joint.

Claims

1. A composite exhaust gas recirculation cooler, comprising: a first component made of at least one plastic and ceramic; and a second component made of a material that is at least predominantly aluminum; wherein the two components abut one on top of the other in a connecting area where the two components are connected to each other via a friction stir weld joint without any filler material to form a diffusion bond there between; wherein the first component is reinforced in the connecting area and includes a cooler shell and two cooler bottoms at opposing ends of the cooler shell in an exhaust gas flow direction, and the second component is configured as at least one of a coolant nozzle and a housing; and wherein one cooler bottom is thicker than the other cooler bottom.

2. The composite exhaust gas recirculation cooler according to claim 1, wherein the cooler is configured as an I-cooler.

3. The composite exhaust gas recirculation cooler according to claim 1, wherein the cooler has at least one of a valve housing and a flap housing.

4. The composite exhaust gas recirculation cooler according to claim 1, wherein the cooler has a bypass channel.

5. The composite exhaust gas recirculation cooler according to claim 1, wherein the connecting area of the two components is stiffened by the cooler bottoms.

6. The composite exhaust gas recirculation cooler according to claim 1, wherein the cooler bottoms have at least one of a generally rectangular and oval cross-section.

7. The composite exhaust gas recirculation cooler according to claim 1, wherein the one cooler bottom is a reinforced cooler bottom.

8. The composite exhaust gas recirculation cooler according to claim 2, wherein the cooler has at least one of a valve housing and a flap housing.

9. The composite exhaust gas recirculation cooler according to claim 8, wherein the cooler has a bypass channel.

10. The composite exhaust gas recirculation cooler according to claim 9, wherein the connecting area of the two components is stiffened by the cooler bottoms.

11. The composite exhaust gas recirculation cooler according to claim 10, wherein the cooler bottoms have at least one of a generally rectangular and oval cross-section.

12. The composite exhaust gas recirculation cooler according to claim 1, wherein the cooler has a valve housing.

13. The composite exhaust gas recirculation cooler according to claim 1, wherein the cooler has a flap housing.

14. The composite exhaust gas recirculation cooler according to claim 1, wherein the second component is configured as a housing.

15. A composite exhaust gas recirculation cooler, comprising: a first component made of at least one of plastic and ceramic; and a second component made of a material that is at least predominantly aluminum; wherein the two components abut one on top of the other in a connecting area where the two components are connected to each other via a friction stir weld joint without any filler material; wherein the first component includes a cooler shell and two cooler bottoms at opposing ends of the cooler shell in an exhaust gas flow direction, and the second component is configured as at least one of a coolant nozzle and a housing; and wherein one cooler bottom is thicker than the other cooler bottom.

16. The composite exhaust gas recirculation cooler according to claim 1, wherein the one cooler bottom has a bent edge with which the one cooler bottom rests flatly against a projection of the cooler shell.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) In the figures, schematically:

(2) FIG. 1 shows a cooler according to the invention in one view,

(3) FIG. 2 shows a sectional view through the cooler according to the invention in a connecting area of two components which are connected in said connecting area by means of a friction stir weld joint,

(4) FIGS. 3a to e show different positions of a pin for generating the friction stir weld joint,

(5) FIG. 4 shows a sectional view through a possible embodiment of a cooler according to the invention having two cooler bottoms, wherein in one cooler bottom, free space for a welding device is provided,

(6) FIG. 5 shows an illustration as in FIG. 4, but with substantially the same cooler bottoms,

(7) FIG. 6 shows again a sectional view through the cooler according to the invention of another embodiment in which a cooler shell is arranged partially inside and partially outside of a diffusor in the connecting area.

DETAILED DESCRIPTION

(8) According to the FIGS. 1 to 6, a cooler 1 according to the invention which can be configured, for example, as an exhaust gas recirculation cooler (EGR) or as a charge air cooler, has a first component 2 made of steel, in particular stainless steel, and a second component made of light metal, in particular aluminum, wherein according to the invention, the two components 2 and 3 are tightly connected, that is welded, to each other in a connecting area 4 by means of a friction stir weld joint. All embodiments shown of the cooler 1 according to the invention represent an I-cooler, wherein said cooler can of course also be configured as an L- or U-cooler. The first component 2 of the cooler 1 according to the invention can be configured, for example, as a cooler shell 5 or as a cooler bottom 6, whereas the second component 3 can be configured, for example, as a coolant nozzle, a holder, an intermediate piece, a housing 7 or as a diffusor 8. In FIG. 1, a housing 7 is arranged on the cooler 1, wherein in said housing 7, a valve device or flap device for controlling the exhaust gas flowing through the cooler 1 can be provided.

(9) According to FIG. 2, a sectional view through the cooler 1 according to the invention shows the generation of the friction stir weld joint in the connecting area 4, for which purpose a welding device 9 with a rotating pin 10 is used. The rotating pin 10 is pressed during the welding process with high force onto the connecting area 4, whereby the material present there is kneaded. However, no melting of the components 2, 3 takes place but only a hot forming of the same, wherein the aluminum forms a diffusion bond with the stainless steel. Here, the pin 10 is pressed with a force of preferably more than 2 kN, in particular more than 5 kN onto the connecting area 4. As mentioned, the first component 2 can be made of steel, in particular stainless steel, whereas the second component 3 can be made of light metal, in particular die-cast aluminum. Depending on the requirements for durability, other material combinations can also make sense.

(10) In FIG. 3a, the pin 10 is pressed from above onto the connecting area 4, whereas in variant 3b, the pin is arranged laterally above a channel centre. In general, the cooler bottom 6 itself which stiffens the connecting area 4 (cf. also FIG. 2) can be reinforced or is reinforced only in said connecting area 4. The cooler bottom 6 can have an angular, in particular rectangular, angular-convex or oval or round cross-sectional shape. According to the FIGS. 3c to 3e, again, different pin positions for generating the friction stir weld joint are illustrated. The exact shape of the cooler 1 is not relevant; it has only to be ensured that at the point at which a connection of two components 2, 3 is generated by means of friction stir welding, the two components 2, 3 to be connected abut smoothly and flat on top of each other as illustrated in FIG. 2.

(11) In the FIGS. 4 to 6, different joining variants of cooler shell 5, cooler bottom 6 and diffusor 8 are illustrated.

(12) When viewing FIG. 4 it is apparent that on the left side of the cooler 1, a free space 11 for the welding device 9 is provided, wherein the cooler bottom 6 on the left side is considerably thinner than the reinforced cooler bottom 6 on the right side of the cooler 1. In addition, the cooler bottom 6 has a bent edge with which the cooler bottom rests flatly against the projection of the cooler shell 5 and the connection can be generated at this location by means of the friction stir welding method. Due to the bent edge, the cooler bottom 6 can be formed relatively thin compared to the cooler bottom 6. Depending on the requirements, such a thin cooler bottom 6 can also be used on both sides of the cooler 1. If a U-shaped cooler 1 is provided, the one cooler bottom 6 can be formed in such a manner. The second component 3 is configured here as a cooler shell 5; it consists, for example, of aluminum, in particular cast aluminum, die-cast aluminum or extruded aluminum. Also, on the left side of the cooler 1, a diffusor 8 or a control valve can be arranged which will be connected via other means to the cooler 1 after the latter is completed.

(13) An illustration similar to the one in FIG. 4 is shown in FIG. 5, wherein here on the left side of the cooler 1, a diffusor 8 is arranged which, in this case, represents the first component 2. The cooler bottom 6 is also shown as a first component 2 of the cooler 1 according to FIG. 5, wherein said cooler bottom is reinforced for implementing the friction stir welding method. Here, the cooler shell 5 encloses the diffusor 8, wherein the diffusor 8, in turn, encloses the cooler bottom 6.

(14) Finally, two additional joining possibilities are illustrated in FIG. 6. A cooler 1 is shown, the cooler bottom 6 of which is also reinforced on the right side, whereas the cooler bottom 6 on the left side is thinner. When viewing the cooler 1 on the right side it is apparent that the diffusor 8 extends on the upper side of the cooler 1 outside of the cooler shell 5. On the lower side, an alternative connection is illustrated. Here, the diffusor 8 is arranged between the cooler shell 5 and the cooler bottom 6, i.e. that the diffusor 8 extends within the cooler shell 5 and is enclosed by the same. Here, the cooler shell 5 and the cooler bottom 6, 6 represent the first component 2, whereas the diffusor 8 represents the second component 3.

(15) With the cooler 1 according to the invention, in case of which individual components 2 and 3 are connected to each other by means of a friction stir weld joint, essential advantages can be implemented: the welding temperature lies below the melting point of the components 2 and 3, high static and dynamic seam strengths can be achieved, no spatters and no smoke are generated, this means, the method is a low-emission method, friction stir welding saves energy no filler material such as, for example, welding wire is required, due to the low welding temperatures, no or only minimal distortion and only little introduction of residual stress in the components 2, 3 takes place, the friction stir welding method can easily be automated.