Patent Publication Number: US-2015068198-A1

Title: Cooling def doser

Description:
BACKGROUND 
     This application generally relates to an apparatus and a method for cooling a diesel exhaust fluid (hereinafter “DEF”) doser. More specifically, this application relates to an apparatus and a method for cooling a DEF doser in a combustion, either compression combustion or spark ignition combustion, engine. For the sake of clarity, embodiments described in this application will be limited to a compression combustion engine, although those same embodiments may be used, with suitable modification, in a spark ignition combustion engine. 
     In some compression combustion engines, such as those that have a selective catalytic reduction (SCR) exhaust management system, like those available from Cummins Emission Solutions of Columbus, Indiana, use a DEF doser with a tip. The tip may have a temperature requirement that should not be exceeded. An exemplary DEF doser tip is in the Denoxtronic® doser available from Robert Bosch GmbH of Stuttgart, Germany. This particular DEF doser tip has a temperature requirement of 120 degrees Celsius. In some applications of a DEF doser, compliance with the DEF doser tip temperature requirement is achieved by flowing engine coolant through the DEF doser while the engine is running However, when the engine is turned off, flow of engine coolant ceases. Temperature of the engine coolant remaining in the DEF doser after the engine is turned off can continue to increase. Because the engine coolant remains essentially stagnant within the DEF doser, the temperature requirement of the DEF doser tip may be exceeded. Exceeding the temperature requirement of the DEF doser tip can lead to damage and to necessary repair of the DEF doser and the associated engine. 
     It is recognized that a DEF doser tip operates in a harsh environment. For example, U.S. Pat. No. 8,347,605 states that some DEF doser tips use water cooling systems. “However, water cooling requires specialized plumbing and additional components that ultimately increase costs and reduce reliability. &#39;605 patent, column 2, lines 19-23. 
     It is desirable to provide an improved method and an apparatus for cooling a DEF doser tip. 
     SUMMARY 
     A number of embodiments of a method and apparatus for cooling a DEF doser tip are provided. According to one embodiment, an apparatus for cooling a DEF doser tip in an engine having an exhaust pipe comprises a cooling block connected with the DEF doser tip. A first port is connected with the cooling block. One end of a cooling conduit connected to the first port. An opposite end of the cooling conduit connected to a first end of a second tube. An opposite end of the second tube connected with a source of engine coolant. A second port is connected with the cooling block. An end of the second port opposite to the cooling block is connected with the source of engine coolant. Means for maintaining configuration of the cooling conduit are disposed between the cooling conduit and the exhaust pipe. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a DEF doser having one embodiment of an apparatus for cooling a DEF doser tip; 
         FIG. 2  is a perspective view of a portion of the embodiment of  FIG. 1 ; 
         FIG. 3  is an elevational view of the embodiment of  FIG. 1 ; 
         FIG. 4  is an elevational view of the embodiment of  FIG. 1  showing dimensions; 
         FIG. 5  is a view similar to  FIG. 4  showing dimensions; 
         FIGS. 6A and 6B  are perspective views of a DEF doser having another embodiment of an apparatus for cooling a DEF doser tip; 
         FIG. 7  is an elevational view of a portion of the embodiment of  FIG. 6  showing dimensions; 
         FIG. 8  is another elevational view of the portion of the embodiment of  FIG. 7  showing dimensions; 
         FIG. 9  is a perspective view of the portion of the embodiment of  FIG. 8 ; 
         FIG. 10  is a perspective view of another portion of the embodiment of  FIG. 6 ; 
         FIG. 11  is another perspective view of the portion of the embodiment of  FIG. 10 ; 
         FIG. 12  is a top elevational view of a further portion of the embodiment of  FIG. 6  showing dimensions; 
         FIG. 13  is a side elevational view of the portion of the portion of the embodiment of  FIG. 12  showing dimensions; 
         FIG. 14  is a perspective view of the portion of the portion of the embodiment of 
         FIG. 13 ; and 
         FIGS. 15A and 15B  are perspective views of a DEF doser having an additional embodiment of an apparatus for cooling a DEF doser tip. 
     
    
    
     DETAILED DESCRIPTION 
     Disclosed herein are multiple embodiments of an apparatus and a method for cooling a DEF doser tip. As the following makes apparent, these embodiments do not require any specialized plumbing or other costly components. The embodiments discussed below provide an improved method and apparatus for cooling a DEF doser tip that improve on other currently available methods and apparatus for cooling a DEF doser tip. 
       FIG. 1  shows a perspective view of one embodiment of a DEF doser tip cooling apparatus  10  attached to an exhaust pipe  11 . For the sake of clarity of understanding, this embodiment will be discussed with respect to its implementation with an after treatment system currently provided by Cummins Emissions Solutions of Columbus, Indiana. That after treatment system uses a DEF doser like the Denoxtronic® doser available from Robert Bosch GmbH of Stuttgart, Germany. Of course, the embodiments discussed herein may be used, with suitable modifications with any appropriate after treatment system using any appropriate DEF doser. 
     The DEF doser tip cooling apparatus  10  comprises a cooling conduit  12  that extends fluidly from a source  14  of engine coolant. A first port  16  is disposed at one end of the cooling conduit  12 . In the illustrated embodiment, the first port  16  is a J2044 connector available from VOSS Automotive GmbH of Wipperfürth, Germany. Other embodiments may use different constructions of the first port  16 . The first port  16  fluidly joins a cooling block  18  for a DEF doser  20  with a first tube  22 . In one embodiment, the first tube  22  is made of a suitable polymer, such as EPDM and the like. An end of the first tube  22  opposite to the end thereof connected to the first port  16  is connected with a coolant loop  24 . The coolant loop  24  is made of a suitable material, such as stainless steel and the like. An end of the coolant loop  24  opposite to an end thereof connected to the first tube  22  is connected to a second tube  26 . In the illustrated embodiment, the second tube  26  is made of a suitable polymer, such as EPDM and the like. An end of the second tube  26  opposite to the end thereof connected to the coolant loop  24  is connected to a second port  28  on the source  14  of engine coolant. A third port  30  on the cooling block  18  is connected with a fourth port  32  on the source  14  of engine coolant thereby forming a fluid circuit from the source  14  of engine coolant, through the second tube  26 , through the coolant loop  24 , through the first tube  22 , through the first port  16 , through the cooling block  18 , through the third port  30  and the fourth port  32  to the source  14  of engine coolant. 
     In an exemplary embodiment, the coolant loop  24  extends about  37  inches from the first tube  22  to the second tube  26 , has an outer diameter of about  5  inches and a wall thickness of about  0 . 5  inches. Further details of one embodiment of the coolant tube  24  shown in  FIGS. 4 and 5  are specified in the following table. 
     
       
         
           
               
               
               
            
               
                   
                   
               
               
                   
                 
                   
                 
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 
                   
                 
                 X 
                 Y 
                 Z 
                 R 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 P0 
                 0.0 
                 0.0 
                 0.0 
                   
               
               
                   
                 P1 
                 70.0 
                 0.0 
                 0.0 
                 20.0 
               
               
                   
                 P2 
                 50.9 
                 118.5 
                 0.0 
                 20.0 
               
               
                   
                 P3 
                 51.6 
                 118.6 
                 −45.0 
                 20.0 
               
               
                   
                 P4 
                 78.2 
                 32.7 
                 −32.3 
                 20.0 
               
               
                   
                 P5 
                 0.3 
                 14.4 
                 −26.8 
                 20.0 
               
               
                   
                 P6 
                 −27.2 
                 8.0 
                 1.5 
                 20.0 
               
               
                   
                 P7 
                 −37.0 
                 5.7 
                 1.5 
               
               
                   
                   
               
               
                   
                     indicates data missing or illegible when filed 
               
            
           
         
       
     
     To maintain configuration of the cooling conduit  12 , a support bar  34  is provided. The support bar  34  supplies rigidity to the cooling conduit  12  so that movement of the cooling conduit  12  is reduced during operation of an associated engine and vehicle. In one embodiment, a first end  36  of the support bar  34  is fixed to a portion of a housing  40  adjacent the DEF doser  20  by suitable means, such as a fastener or the like. In some applications, the first end  36  is fixed to a bore  42  pre-existing on an exhaust management system provided by Cummins Emission Solutions of Columbus, Indiana. A second end  38  of the support bar  34  is joined to an outer surface of the exhaust pipe  11  and/or a portion of the cooling conduit  12 . The support bar  34  is joined to the cooling conduit  12  at multiple locations. In the illustrated embodiment, the support bar  34  is joined to the cooling conduit  12  at two spaced-apart locations indicated by A and B in the Figures. Joints between the cooing conduit  12  and the support bar  34  may be formed by any suitable means, such as brazing and the like. 
       FIGS. 6A and 6B  show another embodiment of DEF doser tip cooling apparatus  10 ′. The DEF doser tip cooling apparatus  10 ′ is substantially similar to the DEF doser tip cooling apparatus  10  shown in  FIG. 1 , hence the like reference numerals for similar elements, except for the differences noted here. Unlike the DEF doser tip cooling apparatus  10 , the DEF doser tip cooling apparatus  10 ′ does not include a linear first tube  22  as shown in  FIGS. 1 and 4 . In the DEF doser tip cooling apparatus  10 ′, the first tube  22  is curved. 
     The coolant loop  24  of the DEF doser tip cooling apparatus  10 ′ has tapered section  44 , shown clearly in  FIGS. 7 through 9 , on an end of the coolant loop  24  opposite to the second tube  26 . Some exemplary dimensions of the structures shown in  FIGS. 7 through 9  are summarized below. 
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 
                   
                 
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 
                   
                 
                 X 
                 Y 
                 Z 
                 R 
               
               
                   
                   
               
               
                   
                 P0 
                 0.0 
                 0.0 
                 0.0 
               
               
                   
                 P1 
                 99.4 
                 0.0 
                 0.0 
                 20.0 
               
               
                   
                 P2 
                 88.5 
                 −0.8 
                 −45.0 
                 20.0 
               
               
                   
                 P3 
                 −0.5 
                 −13.3 
                 −32.3 
                 20.0 
               
               
                   
                 P4 
                 −6.2 
                 66.5 
                 −28.8 
                 20.0 
               
               
                   
                 P5 
                 −9.2 
                 94.7 
                 1.5 
                 20.0 
               
               
                   
                 P6 
                 −11.7 
                 144.6 
                 1.5 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                   
                 DISTANCE FROM P0 TO P6 = 
                 145.1 
               
               
                   
                 APPROX CTRLINE LENGTH = 
                 362.8 
               
               
                   
                 TUBING OD = 
                 12.825 
               
               
                   
                 WALL THICKNESS = 
                 1.850 
               
               
                   
                   
               
               
                   
                     indicates data missing or illegible when filed 
               
            
           
         
       
     
     The tapered section  44  is joined with a pipe  46  that extends from the tapered section  44  to the first tube  22 . The pipe  46  can be formed from any suitable material, such as a polymer and the like. Use of the pipe  46  facilitates assembly of the DEF doser tip cooling apparatus  10 ′. For clarity, the pipe  46  is shown in dotted lines in  FIGS. 6A , ̂b,  15 A and  15 B. The pipe  46  is shown clearly in  FIGS. 12 through 14 . Exemplary dimensions of the pipe  46  shown in those Figures are summarized below. 
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 
                   
                 
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 
                   
                 
                 X 
                 Y 
                 Z 
                 R 
               
               
                   
                   
               
               
                   
                 P0 
                 0.0 
                 0.0 
                 0.0 
               
               
                   
                 P1 
                 59.5 
                 0.0 
                 0.0 
                 20.0 
               
               
                   
                 P2 
                 48.0 
                 0.0 
                 71.4 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                   
                 DISTANCE FROM P0 TO P2 = 
                 86.1 
               
               
                   
                 APPROX CTRLINE LENGTH = 
                 119.5 
               
               
                   
                 TUBING IO = 
                 9.525 
               
               
                   
                   
               
               
                   
                     indicates data missing or illegible when filed 
               
            
           
         
       
     
       FIGS. 15A and 15B  show a further embodiment of DEF doser tip cooling apparatus  10 ″. The DEF doser tip cooling apparatus  10 ″ is substantially similar to the DEF doser tip cooling apparatus  10 ′ shown in  FIGS. 6A and 6B , hence the like reference numerals for similar elements, except for the differences noted here. Unlike the DEF doser tip cooling apparatus  10 ′, the DEF doser tip cooling apparatus  10 ″ does not include a support bar  34 . Instead, the DEF doser tip cooling apparatus  10 ″ uses a support clip  48  shown in  FIGS. 15A ,  15 B and  16  to maintain configuration of the cooling conduit  12  by joining the cooling conduit  12  with the exhaust pipe. 
     The support clip  48  cooperates with a strap  50  and fittings  52 A and  52 B to maintain configuration of the DEF doser tip cooling apparatus  10 ″. The strap  50  is formed of suitable materials, such as a metal and the like, and is attached to (circumferentially surrounds an outer surface of the exhaust pipe  11  in the illustrated embodiment) the exhaust pipe  11 . In the illustrated embodiment, the strap  50  includes a pair of matching bores  54 A and  54 B. The support clip  48  includes a bore  56  intended to be aligned with the bores  54 A and  54 B on the strap  50 . When suitably assembled, a suitable fastener, such as a bolt and the like, (not shown for clarity) can be inserted through the bores  54 A,  54 B and  56  to join the support clamp  48  with the strap  50  and to join the strap  50  with the exhaust pipe  11 . The fittings  52 A and  52 B couple on one side to the cooling conduit  12  and to the support clip  48  on the other side. 
     Opposite to the bore  56 , the support clip  48  includes opposing fingers  58 A and  58 B shown in  FIGS. 15A ,  15 B and  16 . The fingers  58 A and  58 B include apertures  60 A and  60 B. The apertures  60 A and  60 B mate with corresponding apertures on the fittings  52 A and  52 B. Appropriate fasteners, such as bolts and the like, are inserted through the apertures on the fittings  52 A and  52 B and the apertures  60 A and  60 B on the support clip  48  to join the cooling conduit  12  with the support clip  48  and thus with the exhaust pipe  11 . 
     Considering the various embodiments of the DEF doser tip cooling apparatus  10 ,  10 ′ and  10 ″, it can be appreciated that both the support bar  34  and the support clip  48  together with the strap  50  and the fittings  52 A and  52 B comprise means for maintaining configuration of the cooling conduit  12  disposed between the cooling conduit  12  and the exhaust pipe  11 . Other constructions can be used to realize the means for maintaining configuration of the cooling conduit  12 . These other constructions may be chosen to meet certain needs, such as space limitations, fuel economy, weight, heat, vibration resistance, etc. 
     With structure of various embodiments of the DEF doser tip cooling apparatus being thusly described, operation of the DEF doser tip cooling apparatus will now be discussed. To facilitate understanding, operation of the DEF doser tip cooling apparatus will be discussed using the embodiment of the DEF doser tip cooling apparatus  10  shown in  FIGS. 1 through 5 . However, the following discussion of operation of the DEF doser tip cooling apparatus applies equally to all embodiments of the DEF doser tip cooling apparatus disclosed herein. It is to be noted that further specifications of the DEF doser tip cooling apparatus may become apparent in the following discussion. While operation of the DEF doser tip cooling apparatus is described in a particular order, it is possible that steps of the operation detailed below may be performed in any suitable order and with any appropriately desired modifications. 
     When an engine associated with the DEF doser tip cooling apparatus  10  is operating, under the influence of a water pump, coolant flows from the source  14  of engine coolant through the cooling conduit  12  thereby maintaining the DEF doser tip in compliance with its temperature requirement. When the engine is shut off, the water pump stops operating. Coolant no longer flows through the cooling conduit  12  under the influence of the water pump. Because the water pump no longer provides circulating engine coolant, the doser tip can exceed its thermal requirement causing damage. 
     However, the DEF doser tip cooling apparatus  10  provides movement of engine coolant through the cooling block  18  even though the engine and the associated water pump are no longer operating. There is engine coolant present at the first port  16  and there is engine coolant present at the third port  30 . Temperature of the engine coolant present at the first port  16  differs from the temperature of the engine coolant present at the third port  30 . This temperature differential drives movement of engine coolant irrespective of lack of operation of the water pump. Dimensions of the apparatus  10  are chosen so that there is always at least about  16  cubic centimeter volume of engine coolant on each side (one side being adjacent the first port  16  and another side being adjacent the third port  30 ) of the DEF doser  20 . In this manner, the likelihood that the DEF doser tip exceeds its thermal requirement after engine shut down is reduced. 
     
       
         
           
               
               
             
               
                   
               
               
                 REFERENCE CHARACTER 
                 ELEMENT 
               
               
                   
               
             
            
               
                 10 
                 DEF doser tip cooling apparatus 
               
               
                 10′ (FIGS. 6A, 6B) 
                 DEF doser tip cooling apparatus 
               
               
                 10″ (FIGS. 15A, 15B) 
                 DEF doser tip cooling apparatus 
               
               
                 11 
                 Exhaust pipe 
               
               
                 12 
                 Cooling conduit 
               
               
                 14 
                 Source of engine coolant 
               
               
                 16 
                 First port 
               
               
                 18 
                 Cooling block 
               
               
                 20 
                 DEF doser 
               
               
                 22 
                 First tube 
               
               
                 24 
                 Coolant loop 
               
               
                 26 
                 Second tube 
               
               
                 28 
                 Second port 
               
               
                 30 
                 Third port 
               
               
                 32 
                 Fourth port 
               
               
                 34 
                 Support bar 
               
               
                 36 
                 First end (of 34) 
               
               
                 38 
                 Second end (of 34) 
               
               
                 40 
                 Housing 
               
               
                 42 
                 Bore (on 40) 
               
               
                 44 
                 Tapered section 
               
               
                 46 
                 Pipe 
               
               
                 48 
                 Support clip 
               
               
                 50 
                 Strap 
               
               
                 52A, 52B 
                 Fittings 
               
               
                 54A, 54B 
                 Bore (on 50) 
               
               
                 56 
                 Bore (on 48 for 54) 
               
               
                 58A, 58B 
                 Fingers (on 48) 
               
               
                 60A, 60B 
                 Aperture (on 58A, 58B)