Heat exchanger

Abstract

A heat exchanger, in particular a charge air cooler or an exhaust gas cooler for an internal combustion engine, comprising a plurality of essentially parallel tubes and at least one collector box on the output side, the tubes each emptying into the collector box on the output side, and a gas flow flowing from the tubes into the collector box and from the collector box into an outlet of the collector box, a structure for interacting with the gas flow being provided at least one of the tubes or collector box, a condensation being transported to the outlet with the aid of the structure.

Claims

1. A heat exchanger for an internal combustion engine, the heat exchanger comprising: at least one collector box provided on an output side, the collector box having a bottom surface, an upper surface that opposes the bottom surface and side surfaces arranged perpendicular to the bottom surface and the upper surface; a plurality of substantially parallel tubes positioned outside of the collector box, the tubes each emptying directly into the collector box at one of the side surfaces of the collector box, such that an end of each tube opens into the collector box, wherein a gas flow flows from the tubes into the collector box and from the collector box into an outlet of the collector box; and a structure configured to interact with the gas flow is provided at at least one of the tubes or another one of the side surfaces of the collector box, the structure configured to transport a condensation to the outlet, wherein the outlet projects outward from the upper surface of the collector box, such that an extending direction of the outlet is perpendicular to an extending direction of the plurality of tubes, wherein a width of the outlet is greater than a width of the structure, wherein an upper end of the structure is positioned inside of the outlet, such that the condensation is transported into the outlet from the upper end of the structure, wherein the gas flow flows into the outlet directly from the collector box, such that the gas flow bypasses the structure, and wherein the collector box is completely enclosed by the side surfaces, the upper surface and the bottom surface except for openings provided to accommodate the end of each tube that opens into the collector box at the one side surface and the outlet that projects from the upper surface of the collector box.

2. The heat exchanger according to claim 1, wherein the structure includes a projection of the tubes into the collector box.

3. The heat exchanger according to claim 1, wherein the structure includes a modulation of an edge of at least one of the tubes on the outlet side, in particular an upward bending of the edge and/or a corrugation.

4. The heat exchanger according to claim 1, wherein the collector box is configured as a longitudinal cavity, a cross-section of the collector box increasing over the area of the emptying tubes in a direction of the gas flow.

5. The heat exchanger according to claim 4, wherein a wall of the collector box opposite the tubes is inclined in a direction perpendicular to the tubes.

6. The heat exchanger according to claim 1, wherein the structure includes at least one conducting member provided in the collector box, the gas flow being guided in a grazing manner along a wall of the collector box via the conducting member.

7. The heat exchanger according to claim 6, wherein the conducting member is configured as a conducting plate or as a conducting vane.

8. The heat exchanger according to claim 1, wherein the collector box has a sump for the condensation, the structure being configured as at least one separation edge provided in the area of the sump.

9. The heat exchanger according to claim 1, wherein the collector has a sump for the condensation, the structure including a condensation channel that leads from the sump to the outlet, and wherein the gas flow passes over an end of the condensation channel on the outlet side.

10. The heat exchanger according to claim 9, wherein a section of the condensation channel is configured as a separate channel or a channel integrated into the wall of the collector box on an outside or on an inside of the collector box.

11. The heat exchanger according to claim 9, wherein a retaining member is provided immediately above the sump for influencing a pressure in the area of the sump, the retaining member configured to be integrated with a wall of the condensation channel.

12. The heat exchanger according to claim 9, wherein a nozzle-like cross-sectional constriction of the outlet is provided in an area of the end of the condensation channel on the outlet side.

13. The heat exchanger according to claim 9, wherein the condensation channel is a tube, a portion of the tube being attached to an inner surface of the collector box such that the condensation channel is integrated to an inside of the collector box.

14. The heat exchanger according to claim 1, wherein a turbulence member configured as an inner fin is inserted into each of the tubes, the turbulence member having a projection over the end of the tube and extending into the collector box.

15. The heat exchanger according to claim 14, wherein the projection of the turbulence member is provided with a bend in the direction of the outlet.

16. The heat exchanger according to claim 1, wherein the collector box extends substantially in the direction of gravity, the tubes extending in a substantially horizontal direction.

17. The heat exchanger according to claim 1, wherein the outlet is smaller in cross-section than the collector box.

18. The heat exchanger according to claim 1, wherein the upper end of the structure terminates inside of the outlet.

19. The heat exchanger according to claim 1, wherein the structure is attached directly to the collector box.

20. The heat exchanger according to claim 1, wherein the outlet directly contacts the collector box.

21. The heat exchanger according to claim 1, wherein the upper end of the structure projects outward from the upper surface of the collector box.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

(2) FIG. 1 shows a schematic sectional view of a heat exchanger in the form of a charge air cooler according to the prior art;

(3) FIG. 2 shows a schematic representation of an internal combustion engine having a low-pressure exhaust gas recirculation system and a heat exchanger according to the invention in the form of a charge air cooler;

(4) FIG. 3 shows a second exemplary embodiment of a heat exchanger according to the invention, having multiple alternative or additional modifications.

(5) FIG. 4 through FIG. 14 show further exemplary embodiments of a heat exchanger according to the invention.

DETAILED DESCRIPTION

(6) A heat exchanger designed as a charge air cooler according to the prior art (FIG. 1) comprises a collector box 1 on the input side having an inlet 1a, a collector box 2 on the output side having and outlet 2a and a plurality of tubes 3 extending in the horizontal direction between collector boxes 1, 2 in the form of flat aluminum tubes. Tubes 3 are accommodated in bases 4 of the collector boxes and terminate flush therewith.

(7) Fins 5, through which cooling air flows (perpendicular to the plane of the drawing), are provided between flat tubes 3. The charge air cooler according to FIG. 1 is a direct charge air cooler for cooling using airstream. In principle, an indirect charge air cooler or the like may also be provided. The gas flow flows from inlet 1a through collector box 1 on the input side, is distributed to tubes 3, collected again in collector box 2 on the output side and then flows to outlet 2a. Condensation may accumulate, in particular, on the insides of tubes 3, this condensation accumulating mainly on the bottom of collector box 2 on the output side.

(8) A particularly large amount of condensation accumulates if the charge air cooler is used as part of an exhaust gas recirculation system, as in FIG. 2, for example a low-pressure exhaust gas recirculation system or even a high-pressure exhaust gas recirculation system which is supplied upstream from the charge air cooler, or if an exhaust gas/air mixture flows through the charge air cooler in another manner.

(9) The illustrated gas supply system includes an internal combustion engine 6a, an exhaust gas turbine 6b, a particle filter 6c, an exhaust gas cooler 6d, a compressor 6e and a charge air cooler 6f according to the invention, in which a mixture of compressed fresh air and added exhaust gas is cooled.

(10) In a first exemplary embodiment according to FIG. 3, it is generally provided that tubes 3 have a projection 7 beyond base 4 at least in the area of collector box 2 on the output side, via which the tubes extend into collector box 2 and the gas flow located therein. Improved atomization of the condensation accumulating in tube 3 is thereby achieved at the edge of the end of the tube.

(11) In a first modification 7a (see top view of a tube end in FIG. 3), a lower edge of flat tube 3 is bent upward, which achieves a nozzle-like cross-sectional constriction at the end of the tube and further improves atomization. In a further modification 7b, both long edges of the end of flat tube 3 are bent upward, which, on the one hand, improves atomization and, on the other hand, deflects the gas flow in the direction of outlet 2a.

(12) In a further detail design, at least the lower edge of the flat tube end is provided, in the present case, with a crenellated corrugation 7c, which achieves a further improved atomization of the condensation accumulating on the end of the tube.

(13) In the exemplary embodiment according to FIG. 4, collector box 2 is designed in such a way that its flow cross-section increases continuously from a lower sump 2b in the direction of outlet 2a, so that a uniform flow velocity of the gas is achieved in collector box 2 on the basis of successively emptying tubes 3. For this purpose, wall 8 of collector box 2 opposite tubes 3 is designed to be inclined [in a direction] perpendicular to tubes 3 or to the plane of base 4. This has the additionally advantageous effect that the incident gas flow grazes the entire length of wall 8, so that a condensation film forming on wall 8 is better transported in the direction of outlet 2a, in particular against gravity.

(14) In the exemplary embodiments according to FIG. 5 and according to FIG. 6, conducting means 9, 10 are each situated in collector box 2. In the first example according to FIG. 5, conducting members 9 are designed as bent conducting plates which intensively conduct the gas flow exiting tubes 3 to opposite wall 8 of collector box 2. A condensation film located on wall 8 is transported more effectively hereby to outlet 2a. In the case of conducting vanes 10 according to FIG. 6, the shape of conducting vanes 10 additionally achieves a constriction 10a between adjacent vanes, so that local increases in the flow velocity are achieved for the gas flow in collector box 2. In a suitable design, this also achieves a further improvement in the transport of condensation along wall 8. Conducting vanes 10 may be made, for example, of plastic molded parts. In principle, conducting members 9, 10 may be designed to be integrated into the collector box, which may also be, for example a plastic molded part, for example made of a polyamide.

(15) In the exemplary embodiment according to FIG. 7, separation edges 11 of different shapes are provided in the area of sump 2b of collector box 2, these separation edges extending continuously over the entire width of the collector box in the case of a first detail design 11a (see detail representation of the separation edge in the top view) and having crenellated interruptions for the purpose of further improving their function in the case of a second detail design 11b. Due to these separation edges, the condensation of sump 2b may be atomized with the aid of the gas flow, thereby improving the removal of condensation from the sump with the aid of the gas flow.

(16) FIG. 8 through FIG. 11 each show exemplary embodiments in which a condensation channel 12 is provided which extends from sump 2b to outlet 2a. The gas flow in outlet 2a passes over an end 12a of condensation channel 12 on the outlet side at a relatively high velocity, so that a low pressure is provided in condensation channel 12 by means of which the condensation is extracted from sump 2b to outlet 2a.

(17) Depending on the requirements, the condensation channel may be designed according to FIG. 8 as an external line, in the present case in the form of a hose 14 connected to a connecting piece 13. Alternatively, it may also be designed to be integrated with collector box 2 on the outside of collector box 2 according to FIG. 9 or on the inside of collector box 2 according to FIG. 10. Depending on the design of the collector box, this may be accomplished using metal sheets or by an integrated design in the form of a plastic casting or the like.

(18) In the example according to FIG. 11, a retaining member 15 is additionally provided in the area of the sump, by means of which the gas flow exiting tubes 3 in the lower collector box area is retained so that an improved removal of the condensation through condensation channel 12 is achieved by static pressure on the fluid surface of sump 2b. The suction effect in outlet 2a at end 12a of the condensation channel is further improved by a nozzle-like cross-sectional constriction 16 in outlet 2a. The velocity of the gas flow in the area of condensation channel end 12a and thus the low pressure produced therein are increased by cross-sectional constriction 16.

(19) FIG. 12 shows a variant of the condensation channel illustrated in FIG. 11, in which the condensation is transported primarily by atomizing and carrying along fluid droplets and by driving a water film. If the sump level rises due to heavy condensation, the increasing constriction between the water level and retaining member achieves a greater flow velocity and increased transport of condensation. If the level increases even further and completely closes the cross-section, the condensation is further removed in the same manner as in FIG. 11.

(20) In the example according to FIG. 12, retaining member 15 and a wall of condensation channel 12 are provided with an integrated design in the form of a sheet metal molded part. Depending on the requirements, these elements may also be made of multiple components.

(21) FIG. 13 shows an exemplary embodiment in which an integrated design of retaining member 15 and condensation channel 12 is provided and for which a separation edge 11 is provided in the area of sump 12b for the purpose of further improvement. Separation edge 11 forms a part of the lower inlet of condensation channel 12. A cross-sectional constriction 16 is also provided in the area of outlet 2a. On the whole, the example according to FIG. 13 thus combines features from the examples according to FIG. 7, FIG. 11 and FIG. 12.

(22) In the exemplary embodiment according to FIG. 14, a turbulence member 17 in the form of an inserted and soldered inner fin, in the present case a connecting fin, is provided in some of tubes 3. According to the invention, a projection 17a of the connecting fin extends beyond the tube end and into collector box 2 on the outlet side. The condensation accumulating on the inner walls of tubes 3 is driven by the gas flow within the tubes to the tube end, from where the condensation flows onto projection 17a of the connecting fin, from where it is atomized and/or vaporized by the gas flow. Projections 17a may also be bent upward (not illustrated), in particular in the direction of outlet 2a, so that effects of conducting members are simultaneously achieved by projections 17a, having in particular the effect according to the exemplary embodiments in FIG. 5 and FIG. 6.

(23) It is understood that the features of the individual exemplary embodiments may be reasonably combined with each other, depending on the requirements.

(24) Although the heat exchanger according to the invention is illustrated in all exemplary embodiments as a direct charge air cooler or a charge air cooler through which air flows, any other design is also possible, in particular the design of a direct or fluid-cooled charge air cooler or exhaust gas cooler.

(25) The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.