Abstract:
An oil filter/cooler includes a finned metal canister attached to an oil return pipe by a port nut, and houses a replaceable filter cartridge. Oil transport conduits are located on the outside of the fins, transporting oil from the exit port on the motor to the distal end of the oil filter/cooler. The oil is then channeled back toward the oil return pipe, moving radially outward through the replaceable filter cartridge, before traveling again to the center line of the oil filter/cooler and through the port nut and oil return pipe.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to oil filtering, and particularly to filtering of motor oil on a motorcycle or other open engine vehicle wherein it is also desired to cool the motor oil during filtering. 
       BACKGROUND OF THE INVENTION 
       [0002]    Oil filters for use in filtering motor oil on vehicle engines are well known. In most designs, the oil filter is not an in-line filter (at least not directly in line), but rather filters at a terminal location, with the oil exit port from the engine being directly adjacent the oil return port, i.e., so both ports are on the same, proximal side of the oil filter. In the most common design, using a so-called “spin-on” type oil filter, the oil return port of the engine is a threaded pipe defining a central axis of the oil filter, with the threads being used to hold the oil filter to the engine. A popular size of a spin-on oil return port is a ¾ inch outside diameter pipe with exterior threads (¾-16 UNF class 3 threads). The oil exit port from the engine is next to the oil return pipe, usually fluidly connected to an annular recess encircling the oil return port. After the oil leaves the engine, the oil is filtered through a filter medium, such as radially inward through an accordioned paper filter element. In some arrangements, the oil could alternatively travel in the opposite direction, i.e., entering the filter though the threaded central pipe, moving radially outward through the paper filter element, and exiting the filter adjacent but radially outward from the threaded central pipe. 
         [0003]    Some engines perform better if the motor oil is cooled during use. Accordingly, it is known to design an oil filter body with fins to facilitate heat transfer from the filter body. Such a finned filter body can be referred to as a filter/cooler. 
         [0004]    The majority of oil filters utilize an outer metal casing, which is part of a disposable filter. However, disposal of the metal casings creates environmental issues. Accordingly, oil filters and filter/coolers are known which have a reusable housing around a disposable filter element. Applicant&#39;s U.S. Pat. Nos. 4,401,563 and 5,548,893 show examples of this and are incorporated by reference. Still, improvements can be made to these reusable oil filter/cooler structures. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    The present invention is an oil filter/cooler and a method of filtering and cooling oil. Oil transport conduits are located on the outside of a finned metal housing, transporting oil from the exit port on the motor to the distal end of the oil filter/cooler. The oil is then channeled back toward the oil return port on the engine through the filter element within the finned metal housing. In the preferred embodiment, as the oil moves proximally within the finned metal housing, the oil moves radially outward through the disposable filter element, before traveling again to the center line of the oil filter/cooler and through the return port. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is an exploded perspective view of a preferred embodiment of an oil filter/cooler in accordance with the present invention. 
           [0007]      FIG. 2  is a cross-sectional view of the oil filter/cooler of  FIG. 1  in use in cooling and filtering oil from an engine, it being noted that which direction is “up” or “down” as depicted depends entirely on the orientation of the oil filter/cooler as determined by the engine. 
           [0008]      FIG. 3  is a perspective view of the canister of the oil filter/cooler of  FIGS. 1 and 2 . 
           [0009]      FIG. 4  is a side view (which could be considered a top or plan view if the filter/cooler is oriented on the engine as shown in  FIGS. 1 and 2 ) of the canister of  FIGS. 1-3 . 
           [0010]      FIG. 5  is a proximal end view of the canister of  FIGS. 1-4 . 
           [0011]      FIG. 6  is a distal end view of the canister of  FIGS. 1-5 . 
           [0012]      FIG. 7  is a perspective view of an end cap of the oil filter/cooler of  FIGS. 1 and 2 . 
           [0013]      FIG. 8  is a side view of the end cap of  FIGS. 1 ,  2  and  8 . 
           [0014]      FIG. 9  is a distal end view of the end cap of  FIGS. 1 ,  2 ,  8  and  9 . 
           [0015]      FIG. 10  is a perspective view of a port nut of the oil filter/cooler of  FIGS. 1 and 2 . 
           [0016]      FIG. 11  is a side view of the port nut of  FIGS. 1 ,  2  and  10 . 
           [0017]      FIG. 12  is a distal end view of the port nut of  FIGS. 1 ,  2 ,  10  and  11 . 
           [0018]      FIG. 13  is a perspective view of an alternative port nut for use with the oil filter/cooler of  FIGS. 1 and 2 . 
           [0019]      FIG. 14  is a side view of the port nut of  FIG. 13 . 
           [0020]      FIG. 15  is a distal end view of the port nut of  FIGS. 13 and 14 . 
       
    
    
       [0021]    While the above-identified drawing figures set forth preferred embodiments, other embodiments of the present invention are also contemplated, some of which are noted in the discussion. In all cases, this disclosure presents the illustrated embodiments of the present invention by way of representation and not limitation. Numerous other minor modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of this invention. 
       DETAILED DESCRIPTION 
       [0022]    As shown in  FIGS. 1 and 2 , a preferred embodiment of a filter/cooler  10  of the present invention includes four primary components: a canister  12 , a clamp port nut  14 , a filter cartridge  16  and an end cap  18 . The canister  12  forms the exterior of the filter/cooler  10 . The canister  12  is formed from a heat-conducting metal, and includes a number of fins  20  to accelerate heat transfer from the canister  12 . In the preferred embodiment, the canister  12  is machined from a solid block of 6061 aluminum to ensure rapid heat transfer through the fins  20  while providing a relatively lightweight but very strong construction. The preferred fins  20  extend circumferentially around the canister  12 , which permit air flow in the direction of travel for most motorcycle configurations utilizing the oil filter/cooler  10 . The circumferential fins  20  also provide a pleasing ornamental appearance to the filter/cooler  10 . Alternatively, the fins could extend longitudinally or at an angle relative to the canister. The canister and its fins could alternatively be formed by bending and shaping sheet metal, which is particularly easy to do if the fins extend longitudinally, and the fins can be formed separately from the canister and then integrally attached to the outside of the canister to facilitate heat transfer from the canister to its fins. 
         [0023]    The canister  12  has a proximal end  22  with a circular sealing surface  24  sized to mate with a circular sealing surface  26  on an engine  28  around a threaded oil pipe  30  (shown in  FIG. 2 ). In the preferred embodiment, the canister  12  has an outer diameter of about 3 inches, with the circular sealing surfaces  24 ,  26  being between about 2.4 and 3 inches in diameter. The clamp port nut  14  includes interior threads sized to mate with exterior threads of the threaded oil pipe  30  of the engine  28  (¾-16 UNF class 3 threads). The clamp port nut  14  can be formed from an appropriate plastic or metal, such as machined from  303  stainless steel. To use the filter/cooler  10 , the canister  12  is placed into the proper location on the motor  28 , and then the clamp port nut  14  is rotationally advanced on the mating threaded end of the return port pipe  30 . The clamp port nut  14  secures the canister  12  relative to the engine  28 . To create a seal between the canister  12  and the engine  28 , a compressible gasket or o-ring  32  may be housed between the canister  12  and the circular sealing surface  26  of the engine  28 . Because it&#39;s the clamp port nut  14  and not the canister  12  that mates with the threads on the return port pipe  30 , the proximal side  22  of the canister  12  need not include any threads, and the canister  12  does not need to be rotated while attaching it to the engine  28 . 
         [0024]    The filter cartridge  16  is disposed within the canister  12 . For instance, in the preferred embodiment the filter cartridge  16  is a prior art HD- 1  filter element, originally described in U.S. Pat. No. 4,401,563 and commercially available from the assignee of the present application. The preferred filter cartridge  16  includes a perforated metallic sheath  34  around a paper filter medium  36  (shown in  FIG. 2 ). The paper filter medium  36  extends in an accordion configuration annularly around an oil filtration chamber  38  in the center of the filter cartridge  16 , with the oil filtration chamber  38  being open on its distal end. The axis of the threaded oil pipe  30  coincides with the central oil chamber  38 , and in the preferred embodiment coincides with the axis of the filter cartridge  16 /central oil chamber  38 . The inside-out radial flow direction from the central oil chamber  38  through the filter medium  36  allows the prior art HD-1 filter element  16  to be used with the present invention. The inside-out radial flow direction through the HD-1 filter element  16  also allows the perforated metal sheath  34  to support the paper accordion filter material  36 , with the perforated metal sheath  34  protecting the filter material  36  and the accordion pattern during handling. 
         [0025]    The HD-1 filter element  16  includes a temperature responsive built in relief valve (not shown) to allow media by-pass on cold starts. During normal operation, an end cap  40  on the proximal end of the filter cartridge  16  ensures that the oil must flow radially outward through the filter medium  36  to exit the filter cartridge  16 . The end caps  40 ,  42  are crimped to the metallic sheath  34  to form a fail proof assembly. A spring  44  attached on the annular distal end cap  42  biases the filter cartridge  16  proximally to hold the filter cartridge  16  in place. The distal end cap  42  of the filter cartridge  16  includes a shoulder  48  with an o-ring  50  which mates against a distally facing shoulder  46  of the canister  12  to position the cartridge  16  within the canister  12 . The outer diameter of the perforated metallic sheath  34  is smaller than the inner diameter of the canister  12 , so oil can flow longitudinally toward the proximal end of the filter/cooler  10  after it has moved through the filter medium  36 . The length of the filter cartridge  16  is shorter than the length of the canister  12 , so oil can flow radially inward after passing the proximal end cap  40  of the cartridge  16  to reach the port nut  14  and the oil return pipe  30 . For instance, in the preferred embodiment the canister  12  is about 6 inches long and defines an inner chamber receiving the filter cartridge  16  which is about 4.2 inches long. The filter cartridge  16  is itself (not including the spring  44 ) about 4.2 inches long, meaning a gap is left around the proximal end of the filter cartridge  16  equal to the combined thickness of the distal end cap  42  and the o-ring  50 , i.e., a preferred gap around the proximal end of the filter cartridge  16  of about 0.15 inches. 
         [0026]    The end cap  18  screws into the canister  12  to hold the filter cartridge  16  in place within the canister  12 , such as with about 2¾ inch 16 UNC threads. The end cap  18  is removable from the canister  12  to allow removal and replacement of the filter cartridge  16 . A compressible gasket or o-ring  54  may be disposed between the end cap  18  and the canister  12  to better seal the end cap  18  to the canister  12 . In contrast to many prior art designs, the canister  12  of the present invention can remain attached to the motor  28  during changing of the filter cartridge  16 . 
         [0027]    As shown in  FIGS. 1 and 2 , the canister  12  includes piping  56  or one or more equivalent passageways for oil flow outside the fins  20 . In the preferred configuration, piping is provided by two rubber tubes  56  running longitudinally on the outside of the canister  12 , and the oil flows in the distal direction through the two rubber tubes  56 . This piping is attached to the canister  12  by a fitting  58  on each end. For instance, the preferred embodiment utilizes four metal L-shaped fittings  58  such as formed of brass, which are threadedly attached to the canister  12 . The preferred fittings  58  are commonly commercially available such as with a ⅛ inside diameter, ⅛″ NPT thread having about a 0.4 inch outside diameter on the threads. The two fittings  58  on the proximal side of the canister  12  communicate with an oil reception chamber  60  on the proximal side of the canister  12 . The two fittings  58  on the distal side of the canister  12  communicate with the central oil filtration chamber  38 . Because the canister  12  attaches to the engine  28  without rotation of the canister  12 , the tubes  56  can be positioned in a circumferential location so as to not interfere with any structure (not shown) on the engine  28 . As shown in  FIGS. 3 and 4 , the exterior of the canister  12  can also be shaped such as with a recess in its cylindrical profile, in this case a flat  62 , to avoid interference with other engine  28  components (not shown). 
         [0028]    A basic unique feature of the present invention is the oil flow direction relative to the cooling and filter surfaces. Namely, the hottest oil is carried, outside the canister  12  and through one or more hoses or tubes  56 , to the distal end of the canister  12 . Then the oil flow direction turns around and flows monotonically within the canister  12  toward the engine  28 . Within the canister  12 , the oil is accordingly hottest at the distal end, and then cools due to the fins  20  and traversal through the filter element  16  from distal to proximal. That is, oil flow within the canister  12  is in a direction opposite the direction of conductive heat flow through the canister  12  from the engine  28 . This is in contrast to many prior art filter/coolers, wherein the hottest oil enters the proximal (closest to the engine  28 ) part of the canister and stays within the canister. 
         [0029]    Heat conducted from the engine block  28  necessarily enters from the proximal side of the canister  12 , which in the invention is opposite the hottest oil. With this heating cross-flow direction (wherein the axial flow of conduction heat is opposite the hot oil flow direction), the canister  12  of the present invention is less likely to develop a temperature gradient from proximal to distal end, resulting in more even and more effective cooling of the oil. 
         [0030]    The oil flow within the canister  12  is in a single direction from one end of the filter element  16  to the other end, which better uses the filter element  16  associated with the cooling function. There is no possibility that a mass or “plug” of cooler oil can set up in the distal end of the filter/cooler  10  while oil only circulates through the proximal end of the filter/cooler  10 . This results in better overall cooling of the oil and more even use of the surface area of the filter element  16 . In contrast, prior art designs (wherein the oil enters and exits from the same proximal side of the filter cartridge) can allow the oil to only utilize the proximal end of a new filter cartridge, when the filter medium is largely unclogged and permits ready flow-through, with substantial oil flow through the distal end of the filter cartridge only occurring after the proximal end of the filter medium has clogged with filtrate. 
         [0031]    By having the cap  18  screwed onto the distal end of the canister  12 , any oil spillage during changing the filter element  16  occurs at a position well removed away from the engine  28 . An additional embodiment includes a stopcock (not shown) or other similar port on the distal end of the filter/cooler  10  (on the cap  18 , or in the distal end of the canister  12 , or in one of the elbow fittings  58 ), allowing oil to be drained from the filter/cooler  10  during changing of the disposable HD-1 filter element  16 . The end cap  18  shown in  FIGS. 1 and 2  has a knurled outer surface to allow hand tightening and opening/removal. 
         [0032]      FIGS. 7-9  show an alternative end cap  64  having a hexagonal head projection  66 . The hex-head  66  on the alternative screw on cap  64  allows for torquing the cap  64  open with a wrench (not shown), in case it gets stuck to the canister  12  during the time period of use. 
         [0033]      FIGS. 10-12  show a first preferred embodiment of a clamp port nut  14 . A distal side of the clamp port nut  14  includes a ¾ inch square drive recess  68 , for mating with a common ¾ inch square drive tool (not shown) extending through the middle of the canister  12  before the HD-1 filter element  16  is positioned in place. The proximal side of the clamp port nut  14  has an outer diameter of about 1.1 inches in diameter, to just fit with a slight clearance within the corresponding proximal side opening through the canister  12 . The distal side of the clamp port nut  14  is wider than its proximal side, such as an outder diameter of about 1⅜ inches, so the clamp port nut  14  can hold the canister  14  to the engine  28  while extending though the corresponding proximal side opening of the canister. 
         [0034]      FIGS. 13-15  show a second preferred embodiment of a clamp port nut  70 . A distal side of this clamp port nut  70  has a hexagonal profile  72 , for wrench or socket tightening. Additionally, the distal side includes recesses  74  for tightening with a screwdriver type of tool (not shown) extending through the middle of the canister  12  before the HD-1 filter element  16  is positioned in place. 
         [0035]    Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.