Patent Publication Number: US-8122859-B2

Title: Nylon body located piston cooling nozzle

Description:
FIELD OF THE DISCLOSURE 
     The present invention generally relates to piston cooling nozzles and more particularly to a piston cooling nozzle having nylon body which includes abutment surfaces for positioning the nozzle relative to the piston and connecting rod by engaging the cylinder liner. 
     BACKGROUND OF THE DISCLOSURE 
     Piston cooling nozzles (PCNs) are known. In general, PCNs deliver oil to the pistons of an internal combustion engine to transfer heat away from the pistons. During operation, some of the heat resulting from fuel combustion is absorbed by the pistons, causing an undesirable temperature rise. Without adequate heat transfer away from the pistons, the carbon deposits may be increased on the pistons. One way to reduce this excess heat is through use of PCNs. 
     A PCN generally has an inlet which receives relatively cool oil from the engine&#39;s oil distribution system and an outlet which directs the cooled oil toward the piston associated with the PCN. The cool oil contacts surfaces of the piston to transfer heat away from the piston. 
     Delivery of the cooled oil to the desired locations on the piston is a performance specification taken into consideration during the design of the PCN. Not only is it desirable to deliver the oil to the surfaces of the piston yielding efficient heat transfer, it is more fundamentally desirable to avoid contact between the PCN and the piston or other moving parts. In certain engine designs, it has been observed that the connecting rod coupled to the piston contacts the tube portion (further described below) of the PCN during engine operation. Of course, repeated contact during the cyclical operation of the connecting rod leads to wear of the tube portion. This wear may manifest itself as a thin wall in a section of the tube portion (i.e., a flat spot on the outer diameter of the tube portion), or even a hole through the tube portion side wall, seriously impairing the PCN&#39;s ability to deliver oil to the piston as desired. In fact, the wear may ultimately lead to bending or breaking of the PCN, which may result in catastrophic engine failure. 
     As the discussion above indicates, precise mounting of the PCN is desirable to permit proper operation and avoid interference with the moving components of the engine. To date, PCN orientation is determined by either a machined locating feature on the engine block or a special interface formed on the block during casting. While machined locating features may permit very precise mounting of the PCNs, the design of some engine blocks makes machining a locating feature difficult to accomplish or otherwise undesirable. On the other hand, since a casting process is not as accurate as a machining process, the orientation of the PCN based on a cast feature of the block can vary somewhat relative to its preferred position due to surface inconsistencies and the relatively loose tolerances of the cast block. 
     One approach to improving the mounting accuracy of PNCs on cast engine blocks is described in U.S. Pat. No. 7,240,643, which is assigned to the present applicant. The approach described in the &#39;643 patent includes brazing a metal tab or bracket to the tube portion of the PCN which functions as a spacer that is indexed off of the bottom end of the corresponding cylinder liner. While this approach is desirable for a variety of reasons set forth in the patent, an alternative PCN configuration may be better suited for certain engine designs. 
     SUMMARY OF THE DISCLOSURE 
     The present disclosure provides a PCN formed from nylon with legs that ensure the tube is precisely located relative to the piston by referencing off of the machined outer diameter of the corresponding cylinder liner. In various embodiments of the present disclosure, the legs may include projections that engage the liner to facilitate installation of the PCN. Additionally, the PCN may include an installation feature that releasably couples to an installation tool to permit a technician to guide the PCN into position during installation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features of this invention and the manner of obtaining them will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the present invention taken in conjunction with the accompanying drawings. 
         FIGS. 1 and 2  are perspective views of a PCN according to one embodiment of the present disclosure. 
         FIG. 3  is a plan view of a PCN according to one embodiment of the present disclosure. 
         FIG. 4  is a perspective view of the PCN of  FIGS. 1 through 3  shown in a mounted orientation. 
         FIGS. 5 and 6  are partially fragmented, perspective views of the PCN of  FIGS. 1 through 3  shown in a mounted orientation. 
         FIG. 7  is a plan view of the PCN of  FIGS. 1 through 3  shown in a mounted orientation. 
         FIG. 8  is a plan view of a PCN according to another embodiment of the present disclosure. 
     
    
    
     Although the drawings represent embodiments of various features and components according to the present invention the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present invention. The exemplification set out herein illustrates embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE DISCLOSURE 
     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings, which are described below. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. The invention includes any alterations and further modifications in the illustrated device and described method and further applications of the principles of the invention, which would normally occur to one skilled in the art to which the invention relates. Moreover, the embodiments were selected for description to enable one of ordinary skill in the art to practice the invention. 
       FIGS. 1 through 3  depict a piston cooling nozzle (PCN) according to one embodiment of the present disclosure for use with a reciprocating engine. PCN  10  generally includes a tube  12  configured to direct cooling oil toward a corresponding piston, a hub  14  configured for mounting PCN  10  to the engine and directing a supply of oil to tube  12  as further described below, and a body  16  (formed of a synthetic polymer such as the nylon family of polymers or other suitable material) configured to permit accurate location of tube  12 . 
     As shown, tube  12  includes a side wall  18 , an interior bore  20 , a first end  22  forming an outlet  24 , and a second end  26  connected to body  16 . Second end  26  also forms an opening (not shown) which is in flow communication with an oil passage  27  ( FIG. 3 ) formed through body  16  from hub  14  to the location of connection of second end  26  of tube  12 . Tube  12  includes a first portion  28  having a longitudinal axis  30  which is substantially parallel to a central axis  32  of hub  14 . Tube  12  further includes a second portion  34  having a longitudinal axis  36  which is substantially perpendicular to central axis  32  of hub  14 . First portion  28  and second portion  34  are joined at an elbow  38 . As should be apparent from the foregoing, interior bore  20  of tube  12  extends from outlet  24 , through first portion  28 , elbow  38 , and second portion  34  to convey cooling oil from oil passage  27  in body  16  to outlet  24 . 
     Hub  14  includes a substantially cylindrical insert  40  formed of, for example, steel, which is mounted in a substantially cylindrical portion  42  of body  16  using any of a variety of suitable mechanical bonding techniques. Insert  40  forms a central opening  43  and includes a side wall  44 , an upper end  46 , and a lower end  48  ( FIG. 3 ). Side wall  44  includes an opening  50  ( FIG. 3 ) aligned with oil passage  27 . 
     Body  16  includes a first side  45 , a second side  47 , a central portion  52  including hub  14  and to which tube  12  is mounted, a first leg  54  extending from central portion  52 , and a second leg  56  extending from central portion  52 . First leg  54  projects substantially radially outwardly from hub  14  and includes an outer abutment surface  58  at its distal end  55 . In the embodiment shown, first leg  54  further includes a first projection  60  which extends from first leg  54  in a direction substantially parallel to central axis  32  of hub  14 . As is further explained below, first projection  60  is optional, and used in certain assembly processes for installation of PCN  10 . Second leg  56  includes an inner portion  62  which also projects substantially radially outwardly from hub  14 . Second leg  56  further includes an outer portion  64  connected to inner portion  62  at an elbow  66 . Outer portion  64  of second leg  56  includes an abutment surface  68  at its distal end  57 . Second leg  56  is shown in the figures as including an optional second projection  70  which extends from outer portion  64  of second leg  56  in a direction substantially parallel to central axis  32  of hub  14 . Like first projection  60 , second projection  70  may be used during installation of PCN  10  as further described below. Both first projection  60  and second projection  70  extend away from first side  45  of body  16  substantially parallel to first portion  28  of tube  12 . 
     Referring now to  FIGS. 4 through 7 , PCN  10  is shown mounted to an engine block (not shown) in its operational orientation. PCN  10  is mounted to the engine block using a banjo bolt  72  (or other suitable flow-through fastener) having a threaded shaft  74  with a central bore  75  ( FIG. 5 ), a head  78 , and a reduced diameter central section (not shown). As shown, banjo bolt  72  extends through hub  14 . As is known in the art, banjo bolt  72  is threaded into a corresponding opening formed in the engine block to which is supplied pressurized cooling oil. As threaded shaft  74  is tightened into the threaded opening of the engine block, head  78 , which has a diameter that is larger than central opening  43  of hub insert  40 , of banjo bolt  72  captures body  16  of PCN  10  against the engine block. Not only does banjo bolt  72  secure PCN  10  to the engine block, banjo bolt  72  communicates oil from the engine block to tube  12 . More specifically, the reduced diameter central section of banjo bolt  72  includes a through hole which extends into central bore  75 . Oil flows from the opening formed in the engine block, through (1) central bore  75 , (2) the through hole in the reduced diameter section of banjo bolt  72 , (3) opening  50  of insert  44 , (4) oil passage  27  of body  16 , and (5) tube  12 . 
     When PCN  10  is mounted to the engine block, tube  12  extends into the interior of the corresponding piston  100 . As best shown in  FIGS. 4 and 6 , even when piston  100  is in the bottom dead center position as shown, the lower edge  102  of the piston skirt  104  does not contact tube  12 . Moreover, tube  12  is spaced between piston skirt  104  and connecting rod  106  such that during operation of the engine, neither piston skirt  104  nor connecting rod  106  will contact tube  12 . Tube  12  is accurately positioned in this orientation and maintained in location by body  16  of PCN  10 . More specifically, abutment surfaces  58  and  68  of first leg  54  and second leg  56 , respectively, engage the side wall of cylinder liner  108  as shown in the figures. The dimensions of liner  108  and its orientation relative to the banjo bolt opening formed in the engine block are tightly controlled during production. Accordingly, abutment surfaces  58 ,  68  may be formed relative to central axis  32  of hub  14  such that when PCN  10  is mounted to the engine block, first portion  28  of tube  12  is positioned safely between piston skirt  104  and connecting rod  106 . The interference between first arm  54  and second arm  56  with cylinder liner  108  prevents PCN  10  (and therefore, tube  12 ) from rotating about central axis  32  out of the desired position. By forming abutment surfaces  58 ,  68  on body  16 , alignment of tube  12  may be ensured without additional processing steps such as attaching an alignment feature to body  16  after body  16  is formed. In an alternative embodiment of the present disclosure, only one of first leg  54  or second leg  56  are formed on body  16  and used to position tube  12  in the manner described above. 
     It should further be understood that abutment surfaces  58 ,  68  may extend onto projections  60 ,  70 , respectively, such that projections  60 ,  70  engage the outer diameter of cylinder liner  108  when PCN  10  is mounted to the engine. For example, in some assembly lines, the engine block is on its side when PCN  10  is installed such that PCN  10  could rotate out of position when banjo bolt  72  begins to engage the corresponding threaded opening in the engine block. By forming PCN  10  with projections  60 ,  70 , as soon as banjo bolt  72  engages the block, abutment surfaces  58 ,  68  formed on projections  60 ,  70 , respectively, engage cylinder liner  108  to maintain PCN  10  in the desired position. 
     In another embodiment of the invention depicted in  FIG. 8 , an installation feature  120  is formed on body  16 . It should be understood that installation feature  120  may be formed on PCN  10 ′ in addition to the alignment feature provided by first leg  54  and second leg  56 , or may be included on other PCN designs that do not incorporate an alignment feature. On some engines, very little space is available around the connecting rods to permit installation of PCNs. The installation technician must hold the PCN and banjo bolt  72  while moving the assembly into position, then fasten banjo bolt  72  to mount the PCN. Generally, the technician holds the assembly with his hands or with the aid of pliers or vice grips. The limited clearance in the area, however, increases the difficulty of installation on certain engines. 
     Installation feature  120 , in one embodiment, includes a substantially cubical recess  122  formed into second side  47  of body  16  on inner portion  62  of second leg  56 . As shown, recess  122  includes four side walls  124 , each having a detent  126  formed therein. Recess  122  further includes a lower wall  128 . Detents  126  are sized and positioned relative to side walls  124  and lower wall  128  to receive the spring loaded balls of a standard sized drive extension for a ratchet wrench. Most drive extensions include an elongated rod or shaft configured on one end to connect to a wrench and outfitted on the other end with one or more captive balls that are spring biased outwardly through corresponding openings formed in the end of the rod. In the same manner that sockets may be attached to the end of such a drive extension, body  16  of PCN  10 ′ may be attached to the drive extension. As the drive extension is inserted into recess  122 , one or more of the spring loaded balls of the extension are urged inwardly against the biasing spring by side walls  124 . When the drive extension is fully inserted into recess  122 , the spring loaded ball(s) register with detent(s)  126  and move outwardly under the force of the biasing spring into detent(s)  126 . The releasable connection force provided by the biasing spring and mated ball(s)/detent(s) is sufficient to permit the installation technician to guide PCN  10 ′ into position by holding the drive extension. After PCN  10 ′ is positioned and mounted to the engine block using banjo bolt  72 , the drive extension may simply be pulled out of recess  122  with minimal force. 
     It should be understood that variations of installation feature  120  may include other attachment and release configurations. For example, a projection may be formed on body  16  with a movable engagement component (i.e., similar to the balls of the drive extension) and the guiding tool may include a recess with detents to receive the movable engagement component. Alternatively, the guiding tool and installation feature  120  may be loosely threaded to maintain engagement during installation, but permit easy removal of the guiding tool after mounting of PCN  10 ′. Other variations may be employed by one skilled in the art consistent with the teachings of the present disclosure. 
     While this invention has been described as having exemplary designs, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.