Abstract:
An oil cooler which is relatively compact in size, yet provides for efficient fluid movement to reduce the temperature of the oil without requiring an external fan, fins or the like is configured to include multiple, parallel paths (i.e., pipes) through which the motor oil flows and is cooled before returning to the system. A plurality of relatively short pipes, grouped in sets, is used to direct the flow of the motor oil from the intake (where the oil leaves the engine and is at its hottest temperature) to the outlet. By the time the oil circulates through the groups of pipes, it will have sufficiently cooled to allow it to return to the system. The contact between the flowing oil and the surfaces of the pipes creates the cooling action as the oil flows therethrough.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/258,788, filed Nov. 6, 2009 and herein incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to an oil cooler for use with a motorized vehicle such as a motorcycle, all terrain vehicle (ATV) or the like and, more particularly, to an oil cooler which is relatively compact in size, yet provides for efficient fluid movement to reduce the temperature of the oil without requiring an external fan, fins or the like. 
       BACKGROUND OF THE INVENTION 
       [0003]    Most motorcycle/ATV engines require cooling, either in the form of “air cooling” or “liquid cooling”. In either case, heat generated from the combustion of gas needs to be removed in order for the motor to continue to operate in a proper fashion. In hot weather (and/or under heavy loads), the temperature of the engine oil can exceed recommended limits. Overheated engine oil loses its ability to lubricate and cool engine parts, ultimately resulting in shorter engine life, accelerated component fatigue and/or failure, increased “heat load” on the vehicle&#39;s engine and radiator, etc. For this reason, auxiliary oil coolers are frequently added to a motorcycle (or other similar vehicle) engine, where the oil flows through the oil cooler and the heat is transferred to the ambient air. Auxiliary oil coolers typically comprise a finned heat exchanger and are typically mounted near the bottom of the engine. US Patent Publication 2009/0020261 issued to G. E. McMillan et al. on Jan. 22, 2009 is exemplary of these prior art arrangements. In the McMillan et al. configuration, the oil cooler includes a heat exchanger resting within a primary drive between an engine pulley and a clutch pulley. A fan within the primary drive pushes (or pulls) air through the heat exchanger. The fan itself may be electrically or mechanically operated and mounted to a base plate or cover plate of the primary drive. 
         [0004]    An alternative prior art oil cooler arrangement takes the form of a pipe through which the heated oil flows and experiences an amount of cooling as it moves through the pipe. One exemplary oil cooler of this type is disclosed in U.S. Pat. No. 6,994,150 issued to S. C. Kline on Feb. 7, 2006. Here, the oil cooler comprises a single tube with an inlet for receiving the elevated temperature oil and an outlet that delivers the cooled oil to a reservoir. 
         [0005]    Unfortunately, there are several disadvantages associated with these designs. For example, the oil cooler is subject to damage from road debris (e.g., rocks, sand, bugs, trash), which can directly impact the cooling fins and reduce (or eliminate) the cooling ability of the device. Also, many designs require relatively large fins to obtain the desired degree of cooling, with the size of the oil cooler impacting the aesthetic qualities of the vehicle. Arrangements such as that of Kline have been found to require an extended length of tubing to provide the desired amount of cooling. 
       SUMMARY OF THE INVENTION 
       [0006]    The needs remaining in the art are addressed by the present invention, which relates to an oil cooler for use with a motorized vehicle such as a motorcycle, all terrain vehicle (ATV) or the like and, more particularly, to an oil cooler which is relatively compact in size, yet provides for efficient fluid movement to reduce the temperature of the oil without requiring an external fan, fins or the like. 
         [0007]    In accordance with the present invention, an oil cooler is configured to include multiple, parallel paths (i.e., pipes) through which the motor oil flows and is cooled before returning to the system. A plurality of relatively short pipes, grouped in sets, is used to direct the flow of the motor oil from the intake (where the oil leaves the engine and is at its hottest temperature) to the outlet. By the time the oil circulates through the groups of pipes, it will have sufficiently cooled to allow it to return to the system. The contact between the flowing oil and the surfaces of the pipes creates the cooling action as the oil flows therethrough. 
         [0008]    It is an aspect of the present invention that the length and diameter of the individual pipes, as well as the spacing between adjacent pipes, are design factors that are taken into consideration for a specific utilization of the oil cooler. Indeed, it has been found that by simultaneously introducing the oil into a group of pipes, the overall flow rate through the oil cooler is reduced when compared to prior art arrangements that use a single flow path through a cooling system. 
         [0009]    Moreover, it is to be understood that while the cooler described in the following description is utilized to reduce the temperature of motor oil, the cooler of the present invention is useful in reducing the temperature of any fluid. 
         [0010]    Other and further advantages and arrangements of the present invention will become apparent during the course of the following discussion and by reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Referring now to the drawings, where like numerals represent like parts in several views: 
           [0012]      FIG. 1  is an isometric view of an exemplary oil cooler formed in accordance with the present invention; 
           [0013]      FIG. 2  illustrates a pipe that may be used within the exemplary oil cooler of  FIG. 1 ; 
           [0014]      FIG. 3  is a front view of the exemplary oil cooler of  FIG. 1 ; 
           [0015]      FIG. 4  is a cut-away view of the exemplary oil cooler of  FIG. 1 , showing the connections between the grouped sets of pipes and the reservoirs utilized to provide fluid movement through the cooler in accordance with the present invention; and 
           [0016]      FIGS. 5-10  illustrate the fluid flow between an intake connection and an outlet connection, indicating in particular the simultaneous flow of fluid through grouped sets of pipes. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    The present invention relates to a relatively compact and efficient oil cooler for use with air-cooled engines as found on vehicles such as, for example, motorcycles or all-terrain vehicles (ATV&#39;s).  FIG. 1  is an isometric view of an exemplary oil cooler  10  formed in accordance with the present invention. Oil cooler  10  may include a pair of brackets  12 ,  14  for attaching oil cooler  10  to an appropriate location on a vehicle (not shown), or other arrangements for attaching the oil cooler to a vehicle may be utilized, as desired. Oil cooler  10  further includes an oil inlet hose connection  16  and an oil outlet hose connection  18 . These connections may further be mounted to oil cooler  10  so as to allow for flexibility in completing the connections to a fluid source and/or drain, e.g., rotatable through 360 degrees. 
         [0018]    In accordance with the present invention, oil cooler  10  further comprises a plurality of pipes  20  (also referred to as a “pipe system”) that is used to circulate the oil and provide sufficient contact between the flowing oil and the ambient air to cool the moving oil as it travels from inlet connection  16 , through pipe system  20 , and exits oil cooler  10  at outlet hose connection  18 . 
         [0019]    As will be described in detail hereinbelow, the individual pipes forming pipe system  20  are interconnected within oil cooler  10  such that the introduced oil will simultaneously pass through a collected group of pipes. In the exemplary embodiment of  FIG. 1 , a set of three pipes are grouped together, so that as the oil enters cooler  10  via inlet hose connection  16 , the oil will simultaneously enter a first set of pipes  20 - 1 . The oil will move downwards through this first set of pipes  20 - 1 , and then flow into a second set of pipes, shown as pipes  20 - 2  in  FIG. 1 . In a similar fashion, the oil will continue to circulate, passing through a third set of pipes  20 - 3  before exiting cooler  10  via outlet hose connection  18 . The embodiment of  FIG. 1  is considered to be a preferred embodiment, utilizing three sets of pipes, each set comprising three separate pipes disposed in a parallel configuration. This arrangement of nine total pipes is considered to provide an optimum flow rate of oil through cooler  10  in terms of providing the desired amount of cooling to the oil. The spacing between adjacent pipes, as described below, is also selected to enable efficient heat transfer from the coil to the atmosphere via the pipes. 
         [0020]      FIG. 2  illustrates an exemplary pipe  20   a , where both the length L and inner diameter d of pipe  20   a  are selected to create an oil cooler that provides the desired amount of cooling to the flowing oil, yet is more compact than various ones of the prior art arrangements. As mentioned above, the specific values of L and d, as well as the spacing between adjacent pipes within pipe system  20 , are all parameters that are selected and controlled by the individual designing a specific oil cooler embodiment. 
         [0021]    A front view of oil cooler  10  is shown in  FIG. 3 , which specifically shows the spacing S between adjacent pipes forming pipe system  20 . In this case, spacing S is measured as the spacing between the center of a first pipe  20   a  and an adjacent pipe  20   b . It is to be understood that this spacing S, like the parameters L and d, is under the control of the designer of a specific embodiment of an oil cooler formed in accordance with the present invention. Additionally, the number of individual pipes forming a specific set is also a design choice, where the use of three pipes to form a set as shown in the figures is considered to be exemplary only. 
         [0022]    In contrast to some prior art arrangements that utilize a single path for fluid movement, the use of shorter, grouped pipes for simultaneously moving the fluid in accordance with the present invention results in a more compact arrangement, which is also more efficient in cooling the oil by exposing more of the oil to the ambient air in a smaller space. In addition, by sending the oil through the grouped pipes  20 , the speed of the oil flow through the cooler is decreased, thereby minimizing air resistance. The spacing S between the pipes is also preferably controlled, in accordance with the present invention, to allow for road debris to easily pass between the pipes and thus overcome the blockage/damage associated with prior art oil coolers that use finned arrangements. Furthermore, inasmuch as enclosed pipes are used, the oil cooler of the present invention is much less sensitive than most prior art coolers to any blockage created by dirt or debris. 
         [0023]      FIG. 4  is a cut-away view of oil cooler  10 , showing a particular combination that allows for efficient fluid flow between the various sets of pipes  20 - 1 ,  20 - 2  and  20 - 3  forming pipe system  20 . As shown, oil cooler  10  includes an inlet chamber  30  that accepts the incoming (relatively hot) oil via inlet hose connection  16 . Chamber  30  is sized and located so as to be in fluid communication with the top openings of the first set of pipes  20 - 1 . The arrows in  FIG. 3  show the downward movement of the fluid along pipes  20 - 1  into a second chamber  32 . As the relatively hot oil moves downward, it will contact the walls of each pipe within first set  20 - 1  (in this example, a set of three pipes) and experience a first degree of cooling. As the “cooled” oil enters second chamber  32 , it will move towards the bottom openings of the second set of pipes  20 - 2 . The fluid is then introduced to pipes  20 - 2  and is forced to flow upwards through pipes  20 - 2  into a third chamber  34 . The oil experiences an additional degree of cooling as it passes through pipes  20 - 2 . 
         [0024]    In similar fashion, the oil within third chamber  34  will flow into the top openings of the third set of pipes  20 - 3 , where it will flow downwards and be further cooled, thereafter entering a fourth chamber  36 . The cooled oil is then directed outward into outlet hose connection  18 , where it will then return to the motor (not shown). 
         [0025]      FIGS. 5-10  illustrate in detail this flow of oil through cooler  10  in the manner described above. The process begins, as shown in  FIG. 5 , with the introduction of the “hot” oil through inlet connection  16  into first chamber  30 . The open top ends of first pipe set  20 - 1  are attached to the bottom of first chamber  30 , so that the hot oil will flow out of first chamber  30  and enter first pipe set  20 - 1 , flowing downward as shown in  FIG. 5 . 
         [0026]    As the hot oil is continued to be introduced into first chamber  30  via inlet connection  16 , the oil flows downward, passing through and filling first pipe set  20 - 1 . The flowing oil will thereafter enter second chamber  32  through a set of bottom openings in first pipe set  20 - 1 , as shown in  FIG. 6 . In accordance with the present invention, the contact between the flowing oil and the surface area of each pipe forming first pipe set  20 - 1  will cause some cooling of the oil to take place. The flowing oil will continue to collect in second chamber  32  and then be directed upwards through end openings in second pipe set  20 - 2 , as shown in  FIG. 7 . The flow of the oil through second pipe set  20 - 2  will further cool the oil passing therethrough, by the contact between the oil and the surfaces of the individual pipes forming second pipe set  20 - 2 . 
         [0027]    The movement of the cooling oil continues, with the oil filling second pipe set  20 - 2  and then collecting in a third chamber  34 , as shown in  FIG. 8 . As the oil begins to fill third chamber  34 , it will start to enter the openings in the individual pipes forming third pipe set  20 - 3 . This step in the process is shown in  FIG. 9 . Again, the cooling oil will flow downward within third pipe set  20 - 3  and be cooled as it contacts the surfaces of the individual pipes. The flowing oil will then collect in a forth chamber  36 , where it will thereafter be discharged from oil cooler  10  via outlet connection  18 , as shown in  FIG. 10 . 
         [0028]    In one embodiment of the present invention, the oil cooler is mounted to the base of the vehicle radiator (not shown), where the temperature of the water, as well as air coming through the radiator, are at their relative lowest values within the vehicle&#39;s engine. By virtue of placing the oil cooler at this location, the cooler water temperature will further enhance the heat loss experienced by the flowing oil. By using groups of pipes with three pipes in each set, where each pipe has a length of approximately 90 mm and an inner diameter of approximately 8 mm, cooling on the order of 15 degrees C. of the oil and 17 degrees C. of the water were obtained. This use of groups of shorter length pipes, as opposed to single and/or longer pipes within the cooler, creates extra cooling length for the oil while optimizing space within the cooler. 
         [0029]    It is obvious that the oil cooler of the present invention may use more or less than three pipes in each set, and may use more or less than three separate sets of pipes. This particular embodiment, however, has proven to be both compact and efficient in removing heat from the oil, as well as the water within the radiator. Moreover, the cooler itself may be used to reduce the temperature of any moving fluid, motor oil being only one specific fluid. In general terms, however, the scope of the present invention is intended to be limited only by the claims appended hereto.