Not applicable.
Not applicable.
Not applicable.
This invention relates to heat exchangers, and more specifically to radiators having a core formed of flat tubes and cooling fins.
Heat exchangers such as radiators having one or more rows of flat tubes with cooling fins forming a core between two collecting tanks or headers are known, for example, from EP 693 617 B1 or DE 43 28 448 C2. Radiators are so-called cross-flow radiators, and are often used in passenger cars. Such radiators generally have soldered tubes and fins in the core, with the core commonly having side plates on opposite sides between the headers (i.e., with the side plates extending parallel to the longitudinal axis of the flat tubes). In aluminum cores, the side plates are generally also made from an aluminum sheet, which sheet may be variously deformed depending upon the design, and are generally soldered to the cooling fins on the outer sides of the core (i.e., the fins on the outer side of the end flat tubes). Such side plates not only protect the fins on the outer side, but reinforce the radiator by adding strength, and assist in mounting the radiator as desired (e.g., in a vehicle). Of course, the side plates also have an effect on the manufacturing cost of the radiator, and on the weight of the radiator.
Radiators are also known in which at least one lower or upper separated tube of a core functions as a vent tube or intake tube. However, such separated tubes are not fully available at least for operational heat exchange. DE 43 28 448 has proposed a core structure having a connection line lying on the bottom which includes part of the flat tubes of the core, where filling of the circuit is produced via this connection line. However, a check valve is required in that proposed core structure in order to separate the collecting tank on the pressure side from the collecting tank on the intake side to achieve uniform flow through all the flat tubes during operation.
In heavy vehicles and utility vehicles, a separately positioned hose line or the like is generally used to fill the cooling loop, with the hose line connected to the equalization vessel incorporated in the cooling loop.
The present invention is directed toward improving upon the above types of radiators.
In one aspect of the present invention, a vehicle radiator is provided including inlet and outlet headers, a soldered core having a plurality of coolant flat tubes joining the inlet header and the outlet header with cooling fins on opposite sides of the coolant flat tubes, and a multifunction flat tube on at least one side of the core. The multifunction flat tube has a greater section modulus than the coolant flat tubes, and is soldered to adjacent cooling fins and the inlet and outlet headers whereby the multifunction flat tube carries coolant from the inlet header to the outlet header.
In one form of this aspect of the invention, a second multifunction flat tube is provided on the opposite side of the core and soldered to adjacent cooling fins and the inlet and outlet headers, the second multifunction flat tube also having a greater section modulus than the coolant flat tubes.
In another form of this aspect of the invention, the radiator is a downdraft radiator with the inlet header on top and the outlet header on the bottom, and the inlet and outlet headers include openings receiving ends of the coolant and multifunction flat tubes. The opening receiving an end of the multifunction flat tube is larger than each of the plurality of openings receiving the coolant flat tubes.
In still another form of this aspect of the invention, the multifunction flat tube has substantially the same length “h” and depth “t” as the core.
In yet another form of this aspect of the invention, the multifunction flat tube is formed by one of soldering and welding.
In a further form of this aspect of the invention, the multifunction flat tube includes walls extending the depth of the core, and the tube walls are deformed along their length between the inlet and outlet headers to define separate coolant passages.
In still another form of this aspect of the invention, the multifunction flat tube includes flat walls extending the depth of the core, and an insert is provided between the flat walls of the multifunction flat tube whereby the insert defines coolant passages through the multifunction flat tube between the inlet and outlet headers.
In yet another form of this aspect of the invention, the multifunction flat tube includes flat walls extending the depth of the core with inward directed protrusions, the protrusions being connected to each other.
In a further form of this aspect of the invention, the inner flow resistance of the multifunction flat tube is substantially smaller than the inner flow resistance of the coolant flat tubes.
In still another form of this aspect of the invention, the multifunction flat tube has a wall thickness substantially greater than the wall thickness of the coolant flat tubes and a tube height substantially greater than the height of the coolant flat tubes. In one advantageous form, the multifunction flat tube wall thickness is at least two times the wall thickness of the coolant flat tubes, with the multifunction flat tube wall thickness being at least about 1.0 mm in a further form. In another advantageous form, the height of the multifunction flat tube is at least two times the height of the coolant flat tubes, with the multifunction flat tube being at least about 10 mm in a further form.
In yet another form of this aspect of the invention, the flat tubes extend generally vertically with the inlet header soldered to the upper ends of the flat tubes, and the radiator further includes a partition in the inlet header defining first and second chambers, the first chamber being above the multifunction flat tube and the second chamber being above the coolant flat tubes, and also includes a filling line between a coolant fill supply and the first chamber for adding coolant to the radiator. In a further form, the filling line slopes down from the coolant fill supply to the first chamber.
In another aspect of the present invention, a vehicle radiator is provided including inlet and outlet headers, a soldered core having a plurality of coolant flat tubes joining the inlet header and the outlet header with cooling fins on opposite sides of the coolant flat tubes, and a multifunction flat tube on at least one side of the core. The multifunction flat tube is soldered to adjacent cooling fins and the inlet and outlet headers whereby the multifunction flat tube carries coolant from the inlet header to the outlet header, and has an inner flow resistance which is substantially smaller than the inner flow resistance of the coolant flat tubes whereby more coolant flows through the multifunction flat tube than flows through an individual coolant flat tube per unit time to influence temperature distribution over the entire radiator.
In one form of this aspect of the invention, a second multifunction flat tube is provided on the opposite side of the core and soldered to adjacent cooling fins and the inlet and outlet headers. The second multifunction flat tube also has an inner flow resistance which is substantially smaller than the inner flow resistance of the coolant flat tubes whereby more coolant flows through the second multifunction flat tube than flows through an individual coolant flat tube per unit time to influence temperature distribution over the entire radiator.
In another form of this aspect of the invention, the radiator is a downdraft radiator with the inlet header on top and the outlet header on the bottom, and the inlet and outlet headers include openings receiving ends of the coolant and multifunction flat tubes. The opening receiving an end of the multifunction flat tube is larger than each of the plurality of openings receiving the coolant flat tubes.
The invention is described in practical examples below. Reference is made to the accompanying drawing for this purpose.
In the drawings:
a-c illustrate an end of one multifunction flat tube which may be used in accordance with the present invention;
a-c illustrate an end of another multifunction flat tube which may be used in accordance with the present invention;
a-b illustrate an end of still another multifunction flat tube which may be used in accordance with the present invention.
A radiator 10 incorporating elements of the present invention is shown in FIG. 1. The illustrated radiator 10 may be used, for example, in heavy vehicles in order to cool the cooling liquid of the internal combustion engine, and is a so-called downdraft radiator in which the inlet collecting tank or header 12 is arranged on the top and the outlet collecting tank or header 14 on the bottom. The inlet header 12 has an inlet connector 20 and the outlet header 14 has a corresponding outlet connector 22 with which the radiator 10 together with an equalization vessel (not shown) and other corresponding elements may be incorporated in a cooling loop (not shown).
The radiator 10 includes a soldered core 26, of a type which is generally known, including alternating arranged coolant flat tubes 30 and cooling ribs or fins 32. In the illustrated radiator 10, the flat tubes 30 may have a height (i.e., minor dimension between the fins 32 on opposite sides of the tubes 30) of only about 1.8 mm, and without inserts therein. Also, in the illustrated radiator 10, the fins 32 are serpentine.
In accordance with the present invention, multifunction flat tubes 40 are provided on opposite sides of the core 26, soldered to the fins 32 on the outer side of the last coolant flat tubes 30 to thereby provide for good heat transfer.
In accordance with the present invention, the multifunction flat tubes 40 also provide a rigid side to the core 26 to prevent outward expansion or bulging of the core 26, whereby the side plates such as used with prior cores of this type may be omitted. The multifunction flat tubes 40 have a significantly higher section modulus Wx, Wy (see
The section modulus Wx, Wy of the multifunction flat tubes 40 is also significantly greater than the section modulus of individual coolant flat tubes 30. Specifically, the multifunction flat tubes 40 are made from a sheet having a greater thickness “b” (see
The multifunction flat tubes 40 have generally the same depth “t” (see
Like the coolant flat tubes 30, the multifunction flat tubes 40 are suitably connected to the inlet and outlet headers 12, 14 on their ends 42 so as to provide coolant flow paths between the headers 12, 14.
Referring now specifically to the embodiment shown in
As described in greater detail in
Moreover, since the multifunction flat tubes 40 are continuously traversed by coolant during operation and therefore participates in heat exchange, the particular multifunction flat tube design chosen may advantageously seek an optimum between providing a short fill time and providing the highest possible heat exchange rate of the multifunction flat tubes 40. During cooling operation, a portion of the coolant continuously flows from the equalization vessel through the filling line 54 into the side chambers 62, 64 and through the multifunction flat tubes 40 so that these can make a contribution to cooling of the coolant, in which the heat is taken off via the cooling fins 32 traversed by cooling air. Specifically, with cores of this type according to the prior art, the temperature distribution ordinarily has a parabolic trend over the width of the radiator, with the maximum temperature line roughly in the center of the core and the outer lying flat tubes generally poorly traversed and hardly participating at all in heat exchange. In accordance with the present invention, the multifunction flat tubes 40 contribute to deliberate equalization of the temperature over the entire radiator 10.
With the
It should also be understood that the inner flow resistance in both multifunction flat tubes 40 do not necessarily need to be equally large, and it would be within the scope of the present invention, and even advantageous in certain designs, to provide unequal flow resistance in the multifunction flat tubes 40 so that the flow amounts in the two multifunction flat tubes 40 may be different. Moreover, provision of only one multifunction flat tube on one side of the core may also advantageously benefit from the present invention in certain designs.
It should thus be appreciated that multifunction flat tubes 40 such as described above may be used not only to improve performance, but may also be used to reduce temperature differences across the core which can lead to stress cracking.
The header plate 84 may include a continuous groove 86 with a seal 88 arranged in the groove 86, whereby the headers 12, 14 may be formed by firmly and tightly mechanically joining the edge of the header plate 84 to the edge a plastic housing 90 (see FIG. 4). As with the
a-c disclose one embodiment of a multifunction flat tube 40a which may be advantageously used with the present invention. The multifunction flat tube 40a advantageously has a bead 92 or similar deformation on its ends 42. This bead 92 serves as a stop of the multifunction flat tube 40a during assembly of the core (i.e., during assembly of the flat tubes 30, 40 the fins 32 with the header plates 84, which are assembled before performing the soldering process). A suitable insert 94 may also be provided in the multifunction flat tube 40a, with the insert 94 suitably secured therein (as by soldering to the long side walls of the tube 40a) to further enhance the stability of the multifunction flat tubes 40a (and thereby the stability of the core 26) as well as providing coolant flow passages providing enhanced heat transfer with the coolant flowing through such tubes 40a.
a-c illustrate another multifunction flat tube 40b which may be advantageously used with the present invention. The tube 40b may be formed of a bent sheet of material suitably sealed, as by soldering or welding, along a longitudinal joint. As illustrated, the tube 40b also includes an insert 94 such as shown in the embodiment of
a-b illustrate yet another multifunction flat tube 40c which may be advantageously used with the present invention. In this embodiment, the long side walls 96 of the tube 40c include inwardly directed protrusions 98 which are suitably connected to the opposite side wall 96 (e.g., by soldering to a similar protrusion 98).
Still other multifunction flat tube designs using these and/or other features could be advantageously used within the scope of the invention. For example, longitudinally extending inwardly directed protrusions could be soldered together (similarly to the longitudinally spaced protrusions 98 of the
It should thus be appreciated that radiators incorporating the present invention may benefit from one or more of the various benefits provided thereby. A filling function can be provided to assist in achieving proper operation of the radiator. Also, a single core design may be used for radiators with or without a filling function. Further, a stable core may be provided without significantly impacting the weight or size of the radiator, whereby the side plates required in the prior art may be omitted. Still further, the ability to assemble the multifunction flat tubes 40 together with the coolant flat tubes 30, without requiring assembly of such side plates, provides manufacturing advantages. Moreover, performance of the radiator may be improved by achieving a more uniform temperature distribution over the entire radiator core dues to the side regions of the radiator being heated more quickly as a result of the multifunction flat tubes.
Still other aspects, objects, and advantages of the present invention can be obtained from a study of the specification, the drawings, and the appended claims. It should be understood, however, that the present invention could be used in alternate forms where less than all of the objects and advantages of the present invention and preferred embodiment as described above would be obtained.
Number | Date | Country | Kind |
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102 42 311 | Sep 2002 | DE | national |
Number | Name | Date | Kind |
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3034770 | Hiersch | May 1962 | A |
4098328 | Cheong | Jul 1978 | A |
4771942 | Arold et al. | Sep 1988 | A |
4791982 | Meyerhofer | Dec 1988 | A |
5101890 | Aoki et al. | Apr 1992 | A |
5186248 | Halstead | Feb 1993 | A |
5236042 | Kado | Aug 1993 | A |
5697433 | Kato | Dec 1997 | A |
6341648 | Fukuoka et al. | Jan 2002 | B1 |
Number | Date | Country | |
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20040112577 A1 | Jun 2004 | US |