Patent Application
20050161519
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The present invention is directed toward heat exchangers, and particularly toward controlling the temperatures of the fluids flowing through heat exchangers.
Heat exchangers in which one fluid (e.g., oil) is cooled by another fluid (e.g., coolant) are well known. In order to control the heat exchanger operation so that the cooled fluid is at a desired output temperature level, control valves for controlling the flow of coolant streams having different temperatures have been used, such as shown in DE 100 19 029 A1, EP 787 929 B1, and EP 829 795 B1.
However, such components are often required to be located in very restricted spaces, such as the crowded engine compartment of a vehicle, making size and space requirements not only important, but often critical design elements which, if not maximized, may result in less than desired heat exchange operation. Thus, while the valve disclosed in DE 100 19 029 A1 may provide desired operation, it typically must extend roughly over the entire wall of the heat exchanger due to its enclosed oil discharge channel outside of the water feed channel (where both channels are generally arranged in diametrically opposite corners of the heat exchanger). As such, the advantageous operational features which could be achieved through use of that valve may not be available where space limitations do not allow its inclusion with the heat exchanger.
The present invention is directed toward overcoming one or more of the problems set forth above.
In one aspect of the present invention, a control valve for a heat exchanger is provided. The heat exchanger is adapted to temper the temperature of a first fluid by heat exchange with a second fluid, and includes separate flow channels for the first and second fluids. The control valve includes a housing adapted to fasten adjacent a wall of the heat exchanger, with the housing defining a chamber separate from a compartment. Further, when fastened to the heat exchanger, the housing communicates the compartment with the flow channels of the second fluid, and opens the chamber to flow of the first fluid via a passage through the adjacent wall of the heat exchanger. A valve member is in the compartment for selectively controlling communication of the compartment with a source of the second fluid, and a thermostat is positioned in the chamber to contact the flow of the first fluid, with the thermostat controlling the valve member responsive to the temperature of the first fluid.
In one form of this aspect of the present invention, a flow deflection element is in the passage. In a further form, the flow deflection element is an obliquely positioned vane in the heat exchanger wall adjacent the chamber. In another further form, the flow deflection element is deformed in the heat exchanger wall.
In another form of this aspect of the present invention, the housing includes first and second connectors, with the first connector being adapted to connect to a first source of the second fluid and the second connector being adapted to connected to a second source of the second fluid. The valve member is controlled by the thermostat to open either the first source, the second source or a combination of the first and second sources to the compartment. The second fluid from the second source is warmer than the second fluid from the first source.
In another aspect of the present invention, a heat exchanger adapted to temper the temperature of a first fluid by heat exchange with a second fluid is provided. The heat exchanger includes a wall, separate flow channels for the first and second fluids, and a control valve. The control valve includes a housing fastened adjacent the wall and defining a chamber separate from a compartment. Further, the housing communicates the compartment with the flow channels of the second fluid, and opens the chamber to flow of the first fluid via a passage through the adjacent wall of the heat exchanger. A valve member selectively controls communication of the compartment with a source of the second fluid, and a thermostat is positioned in the chamber to contact the flow of the first fluid, with the thermostat controlling the valve member responsive to the temperature of the first fluid.
In one form of this aspect of the present invention, a flow deflection element is in the passage. In a further form, the flow deflection element is an obliquely positioned vane in the heat exchanger wall adjacent the chamber. In another further form, the flow deflection element is deformed in the heat exchanger wall.
In another form of this aspect of the present invention, the housing includes first and second connectors, with the first connector being adapted to connect to a first source of the second fluid and the second connector being adapted to connected to a second source of the second fluid. The valve member is controlled by the thermostat to open either the first source, the second source or a combination of the first and second sources to the compartment. The second fluid from the second source is warmer than the second fluid from the first source.
In still another form of this aspect of the present invention, the adjacent wall has a protrusion around the passage.
In yet another form of this aspect of the present invention, the wall is a wall of a flow channel for the first fluid.
In accordance with the present invention, a housingless plate heat exchanger 10 (such as may be used, for example, in a motor vehicle in order to control the temperature of the gear oil through use of the coolant of the vehicle engine) may be provided with a thermostat-control valve 14 to facilitate advantageous operation of the heat exchanger.
As also disclosed in our U.S. patent application entitled “Plate Heat Exchanger” (filed on the same day as the present application), the disclosure of which is hereby incorporated by reference, a thermostat-control valve 14 is provided for controlling the temperature of the coolant based on the oil temperature to provide a desired advantageous temperature of the oil as cooled by the heat exchanger 10. The valve 14 may be suitably mounted in a housing 16 which is suitably secured on a wall defined by one of the heat exchanger plates (e.g., the cover plate 20).
It should be appreciated that only the cover plate 20 of the heat exchanger 10 is illustrated in the Figures. Other than the connection to the cover plate 20 as described herein and the presence of a flow channel for the fluid having its temperature tempered beneath the cover plate 20, whereby the cover plate 20 defines one wall of that flow channel, the details of the heat exchanger 10 may be variously designed. In the illustrated embodiment, flow channels 22 for the oil and flow channels 24 for the coolant are functionally illustrated by arrows in
The housing 16 has a chamber 28 hydraulically separated from a compartment 30. The housing 22 is also suitably secured to the cover plate 20 so as to maintain suitable seals against leaking of fluids. A thermostat 32 protrudes into the chamber 28, with hydraulic separation from the compartment 30 maintained by suitable seals, such as O-rings 34 between the housing 22 and the body of the thermostat 32. As described in greater detail below, the chamber 28 includes the fluid being tempered (e.g., oil) such that the thermostat 32 measures the temperature of that fluid. The tempered fluid is the fluid for which the heat exchanger 10 is provided to raise or lower its temperature, depending on its operating situation, with the goal being to achieve the most optimal possible temperature in all operating situations. As further described herein, this is achieved by corresponding adjustment of the temperature of the other fluid or medium (i.e., coolant, such as water).
Compartment 30 has two connections to sources of coolant (e.g., water), with one connection 36 being for preheated coolant fluid HC and another connection 38 for cooled coolant fluid CC (it will be appreciated from the further description below that which coolant source is to be provided at which connection 36, 38 depends upon the operation of the thermostat 32).
The control valve 14 includes a valve member 40 inserted in the region of the right connection 38 and suitably fastened in sealed fashion, such as by a spring 42 in housing flange 44. A valve stem 46 extends into compartment 30, and a valve disk 48 is biased against the valve stem 46 by a valve spring 50. The valve stem 46 operates with the thermostat 32 whereby at elevated temperatures the valve stem 46 will not be forced to the right (as viewed in
When the valve disk 48 is seated against the housing 16 as illustrated in
When, by contrast, the tempered fluid (e.g., oil) is below the optimum (e.g., during startup), the cool thermostat 32 will cause the valve stem 46 to move to the right to unseat the valve disk 48, whereby preheated coolant HC will enter the heat exchanger 10 through connector 36, compartment 30, and the opening 52 in the cover plate 20. In that case, coolant may be added to heat the tempered fluid until such time as the fluid begins to exceed the optimum, when the thermostat 32 will allow the valve stem 46 to move toward the left. Such change may occur gradually rather than stepwise, whereby a mixture of both preheated and cooled coolant HC and CC may be allowed to pass through compartment 30 to the heat exchanger 10.
In accordance with the present invention, the tempered fluid is directed into the chamber 28 directly from a tempered fluid flow channel 22 so that the thermostat 32 is advantageously positioned to determine the temperature of the tempered fluid. Specifically, the valve 14 is secured adjacent the cover plate 20 defining a wall of a tempered fluid flow channel 22.
In the illustrated embodiment, the cover plate 20 includes a protrusion or deformation 56 which defines the flow channel 22, with such a flow channel 22 being configured to transfer the fluid which has exited the main heat exchanging flow channels 22 to a heat exchanger output connector. Therefore, it should be appreciated that while the flow channel 22 having a wall formed by cover plate 20 may be any accessible flow channel 22 of the heat exchanger 10, connecting the valve 14 to an overflow or transfer channel 22 such as illustrated may be particularly advantageous. In such a case, the fluid directed into the chamber 28 and measured by the thermostat 32 is substantially at the output temperature of the heat exchanger 10.
Such operation may be advantageously accomplished by the presence of a flow deflecting element or vane 60 located in a passage or cut-out 64 in the cover plate 20. It should be appreciated that, since the passage 64 can be provided on a freely selectable location of the wall (i.e., independent of the position of the channels of the heat exchanger 10), not only may the control valve be compactly designed, but it may be readily positioned at different locations dependent upon the space available in the system with which it is to be used. Moreover, it should also be appreciated that it is advantageous from a manufacturing standpoint to form the flow deflecting element 60 as an obliquely positioned vane produced by deformation, representing part of the wall, since the vane 60 can be formed during production of the wall and therefore need not be installed later. However, it should be understood that it would be within the scope of the present invention for the flow deflecting element 60 to be a separate part inserted in the wall passage 64 and fastened there.
The flow deflecting element 60 may extend partially into the flow channel 22 so as to deflect part of the flow of the tempered fluid into the chamber 28 as indicated by arrow 68 in
As shown in the illustrated embodiment, the flow deflecting element 60 is a partially punched-out bracket pivoted at an angle relative to the plane of the plate wall.
It should therefore be appreciated that the present invention may be inexpensively provided with suitable thermostat operation relative to prior art structures in which the thermostat has been located within one of the feed or discharge channels and/or the valve has incorporated an oil channel. It should also be appreciated that this design provides for a compact structure which does not require extension of the valve over the entire length of the heat exchanger. Not only is such a compact size of value in its own right, but the compact size is particularly advantageous in allowing the heat exchanger to be used in many applications which require compact size without requiring undesirable adjustment to other aspects of the heat exchanger in order to fit within the required space.
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 |
|---|---|---|---|
| DE 10 2004 004 22 | Jan 2004 | DE | national |
