Abstract:
A control valve for a heat exchanger adapted to temper the temperature of a first fluid by heat exchange with a second fluid. 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. 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.

Description:
CROSS REFERENCE TO RELATED APPLICATION(S)  
       [0001]     Not applicable.  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not applicable.  
       REFERENCE TO A MICROFICHE APPENDIX  
       [0003]     Not applicable.  
       TECHNICAL FIELD  
       [0004]     The present invention is directed toward heat exchangers, and particularly toward controlling the temperatures of the fluids flowing through heat exchangers.  
       BACKGROUND OF THE INVENTION AND TECHNICAL PROBLEMS POSED BY THE PRIOR ART  
       [0005]     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.  
         [0006]     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.  
         [0007]     The present invention is directed toward overcoming one or more of the problems set forth above.  
       SUMMARY OF THE INVENTION  
       [0008]     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.  
         [0009]     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.  
         [0010]     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.  
         [0011]     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.  
         [0012]     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.  
         [0013]     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.  
         [0014]     In still another form of this aspect of the present invention, the adjacent wall has a protrusion around the passage.  
         [0015]     In yet another form of this aspect of the present invention, the wall is a wall of a flow channel for the first fluid. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]      FIG. 1  is a cross sectional view of one embodiment of a thermostat-control valve according to the present invention;  
         [0017]      FIG. 2  is a perspective view similar to  FIG. 1 ; and  
         [0018]      FIG. 3 a  detail plan view of the flow deflecting element of the illustrated embodiment. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]     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.  
         [0020]     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 ).  
         [0021]     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  FIG. 2 , though it should be appreciated that additional plates (not shown) would be provided in such a plate heat exchanger to define and separate those channels  22 ,  24 . Moreover, it should be appreciated that flow in such channels  22 ,  24  may occur in either direction (e.g., in counter-current or co-current flow), depending upon the desired design, and the arrows point in both directions to illustrate those available design choices. A protrusion  25  of the cover plate  20  beyond the end of the body of the plate heat exchanger  10  (indicated by dashed vertical line  26 ) may be provided for suitable fastening of the heat exchanger  10  to the system with which it is to be used. That is, openings  27  may be provided in the protrusion  25 , with fastening accomplished by means of an elastic base such as damping bushings (not shown). More details of one embodiment of a suitable heat exchanger are disclosed in our incorporated co-filed patent application referenced above.  
         [0022]     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).  
         [0023]     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 ).  
         [0024]     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  FIGS. 1 and 2 ) whereas at cool temperatures the thermostat  32  will force the valve stem  46  to the right against the valve disk  48  and the biasing force of the spring  50 .  
         [0025]     When the valve disk  48  is seated against the housing  16  as illustrated in  FIGS. 1 and 2 , the compartment  30  is closed from the preheated coolant connector  36  and the valve  14  is open between the cooled coolant connector  38  and the compartment  30 . This will typically occur during normal operation when cooling of the tempered fluid is desired (i.e., when the tempered fluid is at a temperature above the optimum), whereby only cooled coolant CC will be caused to flow through the heat exchanger  10  via this connection and suitable flow channels (functionally illustrated by arrows  24 ) in the heat exchanger  10 .  
         [0026]     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 .  
         [0027]     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 .  
         [0028]     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 .  
         [0029]     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.  
         [0030]     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  FIG. 1  so as to intensify contact of the tempered fluid (e.g., oil) with the thermostat  32 . By obtaining an accurate and timely measurement of the tempered fluid&#39;s temperature after it has been tempered, the thermostat  32  may reliably determine whether more or less cooling is desirable, and adjust the mix of cool and preheated coolant CC and HC accordingly.  
         [0031]     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.  FIG. 3  shows a top view of the passage  64 .  
         [0032]     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.  
         [0033]     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.