Abstract:
A cooling apparatus including an elongated body portion having a fluid inlet, a fluid outlet and a fluid channel extending between the fluid inlet and the fluid outlet, wherein the fluid channel includes a generally “G,” “C” or “( )” shaped cross-section.

Description:
BACKGROUND  
       [0001]     The present application relates to apparatus and methods for cooling devices and, more particularly, to apparatus and methods for cooling devices using cooling fluids at low flow rates.  
         [0002]     Electronic control modules (ECMs) are used to control electronic fuel injector systems of modem diesel engines. They enable the diesel engines to meet modem pollution standards while enhancing ease of starting, driveability and performance.  
         [0003]     Normal operation of an ECM causes a certain amount of heat to be generated by the electronics within the ECM. In some circumstances the generated heat may be dissipated to the air surrounding the ECM. However, oftentimes the ECM is placed in a relatively hot area (e.g., near the engine) or in a location where heat is not easily dissipated, thereby requiring auxiliary cooling.  
         [0004]     Liquid coolers have been attached to or included within ECMs to remove the extra heat by circulating various cooling fluids over or through the ECMs. The cooling fluids may be diesel fuel, engine coolant or the like.  
         [0005]     One type of diesel fuel cooling/plumbing system utilizes two fluid lines: one line from the fuel tank to the engine and one line from the engine back to the fuel tank. Such systems have the advantage of utilizing high fluid flow rates (i.e., they pass more fuel through the fluid lines than the engine consumes), thereby producing fluid convection behavior that is capable of cooling the ECM without special shapes being as important.  
         [0006]     An alternative diesel fuel cooling system utilizes a single fluid line (i.e., one line from the fuel tank to the engine). Such systems operate at much lower fluid flow rates (i.e., typically low-speed laminar flow) and therefore offer less efficient heat transfer.  
         [0007]     Specifically, such systems operate at fluid flow rates corresponding to the rate of fuel consumption by the engine (e.g., about 0.25 to about 1.5 liters per minute).  
         [0008]     Accordingly, there is a need for an apparatus and method for efficiently cooling various devices (e.g., ECMs) using cooling fluids at low flow rates.  
       SUMMARY  
       [0009]     In one aspect, a cooling apparatus includes an elongated body portion having a fluid inlet, a fluid outlet and a fluid channel extending between the fluid inlet and the fluid outlet, wherein the fluid channel includes at least one of a generally G-shaped cross-section, a generally ( )-shaped cross-section and a generally C-shaped cross-section.  
         [0010]     In another aspect, a cooling system includes a heated substrate and a cooling unit connected to the heated substrate, wherein the cooling unit includes an elongated body portion having a fluid inlet, a fluid outlet and a fluid channel extending between the fluid inlet and the fluid outlet, wherein the fluid channel includes at least one of a generally G-shaped cross-section, a generally ( )-shaped cross-section and a generally C-shaped cross-section, and a cooling fluid adapted to move through the fluid channel to cool the heated substrate.  
         [0011]     In another aspect, a method for cooling a heated substrate includes the steps of providing a cooling unit having an elongated fluid channel extending therethrough, wherein the fluid channel includes at least one of a generally G-shaped cross-section, a generally ( )-shaped cross-section and a generally C-shaped cross-section, contacting the cooling unit to a substrate and passing a cooling fluid through the fluid channel to cool the substrate.  
         [0012]     Other aspects of the cooling apparatus and method will become apparent from the following description, the accompanying drawings and the appended claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is a side elevational view of one aspect of a cooling unit of the disclosed cooling apparatus;  
         [0014]      FIG. 2  is a side elevational view of a second aspect of the cooling unit of  FIG. 1 ;  
         [0015]      FIG. 3  is a side elevational view of a third aspect of the cooling unit of  FIG. 1   
         [0016]      FIG. 4  is a top plan view of the cooling unit of  FIG. 1 ; and  
         [0017]      FIG. 5  is a front perspective view of an ECM having the cooling unit of  FIG. 3  attached thereto. 
     
    
     DETAILED DESCRIPTION  
       [0018]     As shown in  FIGS. 1-4 , a cooling unit according to one aspect of the disclosed cooling apparatus and method, generally designated  10 , may include an elongated body  12  having a fluid channel (or fluid channels)  14  extending therethrough for receiving a cooling fluid therein. In one aspect, the body  12  may have a length L of about 10 to about 100 centimeters. The fluid channel  14  may have a fluid inlet  16  and a fluid outlet  18 .  
         [0019]     In another aspect, the fluid inlet  16  may be in fluid communication with a fluid source (not shown) such as a fuel tank and the fluid outlet  18  may be in fluid communication with the combustion chamber of an engine (not shown) such that fluid exiting the cooling unit  10  by way of the fluid outlet  18  is passed directly to the engine as fuel. Therefore, the cooling fluid may move though the channel  14  at a relatively low flow rate. In one aspect, the fluid flow rate through the channel  14  may be related to the rate that fuel is consumed by the engine (e.g., about 0.25 to about 1.5 liters per minute).  
         [0020]     In another aspect, the unit  10  may be formed from aluminum. However, those skilled in the art will appreciate that the unit  10  may be constructed from various materials (including metals and non-metals) capable of conducting thermal energy without reacting with the cooling fluid. In one aspect, the body  12  and channel  14  may be shaped and formed by an aluminum extruding process.  
         [0021]     The cooling unit  10  may be provided with an attachment mechanism for securing the cooling unit  10  to a device requiring cooling. For example, as shown in  FIG. 3 , the cooling unit  10  may be provided with mounting flanges  22  having screw holes  24  therein. As shown in  FIG. 4 , the cooling unit  10  may be connected to an ECM  20  with screws  26  such that heat generated by the ECM  20  is transferred to the cooling fluid by way of the cooling unit  10 . However, those skilled in the art will appreciate that the cooling unit  10  may be connected to a device  20  by any technique or combination of techniques known in the art, including thermal adhesives, welding, rivets, bolts or the like.  
         [0022]     As shown in  FIG. 1 , the fluid channel  14  may be generally G-shaped in end view. In another aspect, as shown in  FIG. 2 , the fluid channel  14  may be generally ( )-shaped (i.e., closed parenthesis shaped) in end view. In another aspect, as shown in  FIG. 3 , the fluid channel  14  may be generally C-shaped in end view.  
         [0023]     In one aspect, the channel  14  may have an overall cross-sectional diameter D of about 10 to about 40 millimeters and the channel  14  may have a cross-sectional thickness T of about 1 to about 30 millimeters. The generally G-shaped or generally C-shaped channels may be one continuous channel in cross-section or two or more separate channels in cross-section. The generally ( )-shaped channel may be two or more separated channels in cross-section.  
         [0024]     Without being limited to any particular theory, it is believed that the “G,” “C” and “( )” shaped channels offer improved heat transfer at low, laminar flow rates due to the low thermal resistance and reduced back pressure achieved by the “G,” “C” and “( )” geometries. In particular, it is believed that the “G,” “C” and “( )” geometries minimize thermal resistance by maximizing the internal surface area (i.e., the flux area) of the channel  14  while minimizing the boundary layer thickness (i.e., the flow gap width) of the unit  10 . Furthermore, it is believed that the “G,” “C” and “( )” geometries minimize backpressure by maximizing the cross-sectional flow area of the unit  10 , while eliminating sharp corners and intersections.  
       EXAMPLES  
       [0025]     Two cooling units were prepared as described above using an aluminum extruding process. Each unit was approximately 0.22 meters long. The first unit incorporated a channel having a G-shaped geometry and the second unit incorporated a channel having a ( )-shaped geometry. Each channel had a thickness of about 1.52 mm and an overall diameter of about 14.5 mm. The thermal resistance and backpressure of each unit was determined at various flow rates using mineral oil as the cooling fluid to safely simulate #2 diesel fuel. The results are set forth in Table 1 for the G-shaped channel and Table 2 for the ( )-shaped channel.  
                                     TABLE 1                       Flow Rate   Thermal Resistance   Backpressure       (l/min.)   (° C./Watt)   (psi)                                0.25   0.204   0.05       0.5   0.174   0.095       1   0.144   0.19       1.5   0.126   0.28                  
 
         [0026]    
       
         
               
               
               
             
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                   
               
               
                 Flow Rate 
                 Thermal Resistance 
                 Backpressure 
               
               
                 (l/min.) 
                 (° C./Watt) 
                 (psi) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 0.25 
                 0.215 
                 0.07 
               
               
                 0.5 
                 0.184 
                 0.13 
               
               
                 1 
                 0.154 
                 0.26 
               
               
                 1.5 
                 0.136 
                 0.4 
               
               
                   
               
             
          
         
       
     
         [0027]     Accordingly, cooling units having generally G-shaped and generally ( )-shaped cross-sectional geometries may provide improved heat transfer at low, laminar flow rates.  
         [0028]     Although the cooling apparatuses and methods are shown and described with respect to certain aspects, modifications may occur to those skilled in the art upon reading the specification. The cooling apparatuses and methods are limited only by the scope of the claims.