Abstract:
Featured is a cylinder wall oil delivery system for a reciprocating engine having at least one cylinder and at least one piston movably received in the cylinder as well as a reciprocating engine embodying such a cylinder wall oil delivery system. Such an oil delivery system includes a squirter that is fixably arranged in each cylinder so that oil is directed therefrom to two different areas of the cylinder wall. The squirter includes a first nozzle being orientated so the oil is directed to one of the two cylinder wall areas and a second nozzle being orientated so the oil is directed to the other of two cylinder wall areas. In particular embodiments, the squirter is arranged so the oil targets the piston skirt thrust and anti-thrust travel areas of the cylinder wall and so as to regulate the oil flow from each nozzle.

Description:
FIELD OF INVENTION 
       [0001]    The present invention generally relates to oil lubrication systems, more particularly to oil lubrication systems of a reciprocating engine and yet more particularly to oil lubrication systems of a reciprocating engine that embodies a rolling bearing element in the cranktrain. 
       BACKGROUND OF THE INVENTION 
       [0002]    As shown in  FIG. 1A , many reciprocating engines embody an hydrodynamic cranktrain in which pressurized oil is fed to the crankshaft  10  through cross-drillings and also is fed to the connecting rod big end plain bearing  15  that is disposed between a surface of the crankshaft and the opposing surface of the big end  13  of the connecting rod  12 . In such an engine, the crankshaft  10  is rotatably supported by the main plain bearing  11  secured between the block and the structure (e.g., main bearing cap) secured to the block. The piston  12  is movably received in the cylinder  2  and is rotatably coupled to the crankshaft  10  by the connecting rod  12 . 
         [0003]    In a hydrodynamic bearing pressurized oil crankshaft, the squeezing action between the connecting rod  14  and the big end journal, as well as the amount of side clearance, all combine to provide sufficient oil pressure so that a sufficient oil splash is provided to the cylinder walls  4  every time the crankshaft throw is in the top dead center (TDC) region. In addition, the connecting rod  14  can be configured so as to include a radial hole(s) (e.g., oiling slots  17  as shown in  FIG. 1B ) at the connecting rod big end  13  that provides additional cylinder wall lubrication via an oil spray. The various oil sprays occurring during operation are illustrated in  FIG. 1A . 
         [0004]    In addition to the above-described conventional technique that provides oil as a lubricant between the cylinder walls  4  and the moving elements (e.g., piston, piston rings), other mechanisms or devices have been developed to cool the piston and/or piston rings such as by directing a spray or jet of oil at the piston. For example, one or more nozzles are arranged within a cylinder of a reciprocating engine and these one or more nozzles is/are arranged in the cylinder so as to be aimed at the underside of the piston. In this way, the oil exiting the one or more nozzles impinges on the underneath surfaces of the piston and acts as a coolant oil that cools the piston. 
         [0005]    There is found in U.S. Pat. No. 4,206,726 an oil cooling system for a piston. As indicated therein, each piston has a crown, a depending skirt and a ring-receiving groove on the skirt near the crown. On the underneath side of the piston there is included a central cavity terminating near the crown and coolant receiving means in heat exchange relation to the groove. Two nozzles are provided and arranged within the cylinder so that a first jet of oil is directed to the piston cavity and a second jet directs the oil to the coolant receiving means of the piston for all operating positions of the piston within the cylinder. It is further expressly indicated that means are provided for supplying oil to the nozzles which oil acts as the coolant. 
         [0006]    It is further indicated that, in connection with a highly preferred form of the reciprocating engine, one of the nozzles is arranged so that the first jet is at an angle with respect to the longitudinal axis of the cylinder, so the oil coolant sweeps along the cavity and avoids interference with engine parts. Also, it is indicated that the second nozzle is arranged so that the second jet is generally parallel to the longitudinal axis. 
         [0007]    There is found in Japanese Publication No. 2008-163936 an internal combustion engine including a piston that reciprocatingly moves in a cylinder of a cylinder block. Such an engine further includes a rear side oil jet  210  that injects oil to a skirt inner region and a skirt outer region of the piston from the side of the piston connecting rod. Thus, this publication describes directing oil as a coolant to the underside of the piston between the skirts and piston pin. 
         [0008]    It should be recognized that these conventional systems are based on a reciprocating engine that uses a hydrodynamic bearing pressurized oil crankshaft. However, when a different bearing system is contemplated (e.g., a rollerized crankshaft for example) for use in such reciprocating engine, the operating conditions are different and thus the above described cylinder wall oil delivery system that splashes oil on the cylinder wall will not be effective in providing oil to the cylinder walls. 
         [0009]    As indicated above, in conventional reciprocating engine plain bearings  11 ,  15  are used to rotatably support the connecting rod  14  and the crankshaft  10 . In order to improve engine performance, it has been considered to replace the plain bearings  11 ,  15  with roller element or roller type bearings  21 ,  25  ( FIG. 2 ). Referring now to  FIG. 2  there is shown a cross-sectional side view of a conventional cylinder  2  in which a piston  12  is movably received and which piston is mechanically coupled to the crankshaft  20  via a connecting rod  24 , having a big end  23 . The connecting rod  24 , more particularly the connecting rod big end  23 , is rotatably supported off the crankshaft  10  by a roller bearing  15  that is disposed between a surface of the crankshaft and an opposing surface of the connecting rod big end  23 . Similarly, the crankshaft  20  is rotatably supported by another rolling bearing  21  from cylinder block related structure. In the illustrated oil delivery system, an oil mist supplies lube to the connecting rod roller bearing  15  via axial clearance. 
         [0010]    In contrast to the oil delivery system described in  FIGS. 1A-B , no form of oil spray (or splash) is being provided to the cylinders walls  4 , but rather an oil mist (high pressure atomized oil) impinges on the thrust side of the cylinder wall/liner. Moreover, only about ⅓ rd  of the cylinder bore from BDC gets direct oil mist. As a result, the oil mist region is not adequate to reach the piston ring region at BDC. 
         [0011]    In the lubrication regime shown in  FIG. 2 , oil mist is the primary source of lubricant for the piston group/cylinder wall interface. A conventional cylinder liner for reciprocating engines on the other hand is generally intended for use with an oil spray lubrication regime or methodology. In those cases where an oil mist lubrication regime is the intended methodology for lubrication in a reciprocating engine, the cylinder liners are typically provided with tough coatings (e.g., Nikasil or Galnikai) along the cylinder walls. Such tough coatings are typically found on the liners provided or used in 2 stroke engine applications. 
         [0012]    It thus would be desirable to provide a cylinder wall oil delivery system that can provide an effective amount of oil to the cylinder walls, particularly when the reciprocating engine does not embody a hydrodynamic bearing pressurized oil crankshaft. It also would be desirable to provide a reciprocating engine embodying such a cylinder wall oil delivery system. It would be particularly desirable to provide such an oil delivery system that would be at least as effective as prior art devices/systems for applying oil to the cylinder walls, and more particularly when the reciprocating engine has a rollerized cranktrain. 
       SUMMARY OF THE INVENTION 
       [0013]    The present invention features a cylinder wall oil delivery system for a reciprocating engine having at least one cylinder and at least one piston movably received in the cylinder. Also featured is reciprocating engine that embodies such a cylinder wall oil delivery system. Such an oil delivery system includes a squirter that is fixably arranged in each of at least one cylinder of a reciprocating engine so that oil is directed therefrom to two different areas of the cylinder wall. In particular embodiments, the squirter includes a first nozzle that is orientated so the oil is directed to one of the two cylinder wall areas and the second nozzle is orientated so the oil is directed to the other of two cylinder wall areas. In more particular embodiments, the squirter is arranged so as to regulate the oil flow from each nozzle. 
         [0014]    In yet more particular embodiments, the squirter is arranged in the cylinder so that the oil spray/jet targets a region of the cylinder wall corresponding to piston skirt thrust and anti-thrust travel areas. 
         [0015]    In yet more particular embodiments, the squirter includes a sub-assembly including a first member and a second member that are joined together so as to form the first and second nozzles. Also, the first and second members are configured so as to regulate the flow from each nozzle. In further embodiments, the first and second members are further configured so that the flow from each nozzle lies within a range of desired values or so the flow from each nozzle is about the same. 
         [0016]    In yet further embodiments, the cylinder wall oil delivery system further includes a pressure regulator operably coupled to the squirter so that oil is delivered to the squirter when pressure of the oil exceeds a predetermined value. 
         [0017]    According to another aspect of the present invention there is featured a reciprocating engine including a block having at least one cylinder therein, at least one piston, each piston being movably received in a corresponding cylinder, and a squirter that is fixably arranged in each of the at least one cylinder so that oil is directed therefrom to two different areas of the cylinder wall. Such a squirter includes a first nozzle that is orientated so that oil is directed therefrom to one of the two areas of the cylinder wall and the second nozzle is orientated so that oil is directed therefrom to the other of the two areas of the cylinder wall. 
         [0018]    In yet further embodiments, the squirter is arranged in the cylinder so the oil spray/jet targets a region of the cylinder wall corresponding to piston skirt thrust and anti-thrust travel areas. 
         [0019]    In yet further embodiments, the squirter includes a sub-assembly including a first member and a second member that are joined together so as to form the first and second nozzles. Also, the first and second members are configured so as to regulate the flow from each nozzle. Further, the first and second members are further configured so that the flow from each nozzle lies within a range of desired values or so the flow from each nozzle is about the same. 
         [0020]    In yet further embodiments, the reciprocating engine further includes a pressure regulator operably coupled to the squirter so that oil is delivered to the squirter when pressure of the oil exceeds a predetermined value. 
         [0021]    In yet further embodiments, the block of such a reciprocating engine is configured so as to include 4 cylinders, 6 cylinders, 8 cylinders, 10 cylinders and 12 cylinders, and where the number of pistons corresponds to the number of cylinders. Such cylinders are arranged in the reciprocating engine so as to be in a line, slanted, form a V, or arranged in any of a number of ways as one known to those skilled in the art. 
         [0022]    In yet further embodiments, the reciprocating engine is a four-stroke internal combustion engine or a two-stroke internal combustion engine. 
         [0023]    In yet further embodiments, the reciprocating engine further includes a crankshaft and at least one connecting rod operably coupled to said at least one piston and the crankshaft such that linear motion of the at least one piston in the at least one cylinder causes rotation of the crankshaft. Such a reciprocating engine also further includes a rolling element bearing that rotatably supports the crankshaft during operation of the reciprocating engine. 
         [0024]    In yet further aspects/embodiments of the present invention the oil from such a squirter provides cooling by oil spray wash-up. Also, oil wash-down of the oil sprayed from the squirter further causes lubricant to be splashed onto the connecting rod bearings. Other aspects and embodiments of the invention are discussed below. 
       DEFINITIONS 
       [0025]    The instant invention is most clearly understood with reference to the following definitions: 
         [0026]    As used in the specification and claims, the singular form “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. 
         [0027]    As used herein, the term “comprising” or “including” is intended to mean that the compositions, methods, devices, apparatuses and systems include the recited elements, but do not exclude other elements. “Consisting essentially of”, when used to define compositions, devices, apparatuses, systems, and methods, shall mean excluding other elements of any essential significance to the combination. Embodiments defined by each of these transition terms are within the scope of this invention. 
         [0028]    USP shall be understood to mean U.S. patent Number, namely a U.S. patent granted by the U.S. Patent and Trademark Office. 
         [0029]    TDC shall be understood to mean top dead center and relates to a specific location or position of the piston within the cylinder as it moves linearly within the cylinder. 
         [0030]    BDC shall be understood to mean bottom dead center and relates to a specific location or position of the piston within the cylinder as it moves linearly within the cylinder. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0031]    For a fuller understanding of the nature and desired objects of the present invention, reference is made to the following detailed description taken in conjunction with the accompanying drawing figures wherein like reference character denote corresponding parts throughout the several views and wherein: 
           [0032]      FIG. 1A  is an illustrative cross-sectional side view of a cylinder for a conventional reciprocating engine having a conventional hydrodynamic bearing pressurized oil crankshaft. 
           [0033]      FIG. 1B  is a side view of a the lower end of a conventional connecting rod of  FIG. 1A  showing the radial oiling slots. 
           [0034]      FIG. 2  is an illustrative view of a cylinder having a rollerized crank train but utilizing conventional techniques for lubricating the cylinder walls. 
           [0035]      FIG. 3  is a cross-sectional side view of a cylinder for a reciprocating engine illustrating a cylinder wall oil delivery system according to the present invention. 
           [0036]      FIG. 4  is a bottom view of the cylinder of  FIG. 3 , but with the connecting rod and crankshaft removed for clarity. 
           [0037]      FIG. 5  is a cross-sectional side view of the oil squirter of the present invention when configured for a non-regulated oil pressure application. 
           [0038]      FIG. 6  is a cross-sectional side view of the oil squirter of the present invention when configured for a pressure regulated application. 
           [0039]      FIG. 7  is an enlarged view of the nozzle end portion of the squirter of  FIGS. 5-6 . 
           [0040]      FIG. 8  is a schematic view of an alternative fluid delivery subassembly for an oil squirter according to another embodiment of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0041]    Referring now to the various figures of the drawing wherein like reference characters refer to like parts, there is shown in  FIG. 3  a cross-sectional side view of a cylinder  2  for a reciprocating engine  1  and showing a cylinder wall oil delivery system  100  according to the present invention. Reference also should be made to  FIG. 4 , which is an upward looking view of the bottom of the cylinder  2  of  FIG. 3 , but with the connecting rod and crankshaft removed for clarity. 
         [0042]    As shown in  FIG. 3 , the reciprocating engine  100  includes a cylinder block  102  in which is disposed one or more cylinder bores or cylinders  104 , each cylinder having a wall  106 . A piston  110  is movably received in the cylinder  104  and is rotatably coupled to the crankshaft  120  by a connecting rod  112  at the big end  114  of the connecting rod. A roller bearing  116  (connecting rod big end roller bearing) is provided for rotatable support of the connecting rod by the crankshaft (such as shown in  FIG. 2 ) and another roller bearing, a main roller bearing  122  is provided for rotating support of the crankshaft  120 . 
         [0043]    In further embodiments, such a roller bearing  116 ,  122  or rolling element bearing is any of a number of roller element bearings known to those skilled in the art and appropriate for the intended use. In exemplary embodiments, the roller bearings  116 ,  122  embody a multiplicity of needle bearings or needle bearing elements that are arranged so as to be disposed about an outer surface of the crankshaft  120  and so as to be between an inner surface of the connecting rod big end  114  and the crankshaft outer surface. Such a needle type of roller bearing further includes other structure (e.g., race) that is configured so as to prevent axial movement of the needle bearing elements when installed without interfering with the rotational movement. This arrangement of roller bearings in combination with the crankshaft is referred to herein for simplicity as a rollerized crankshaft. 
         [0044]    Such roller bearing do not require and/or do not support high volumes of pressurized oil as would be required for the hydrodynamic bearings used with a conventional crankshaft. As a consequence of this reduced need for pressurized oil, in the present invention the cylinder block oil feeds to the crankshaft can be restricted and the crankshaft does not have main-to-rod journal cross-drillings. 
         [0045]    Such a reciprocating engine  100  also includes an oil delivery system  150  that is configured and arranged so as to provide oil for lubrication to the cylinder walls  4  as described further herein using an oil spray lubrication regime, and also so as to avoid interference with movable parts of the engine (e.g., crankshaft). In more particular aspects of the present invention, such an oil delivery system  150  includes an oil squirter  152  that is configured so that the oil spraying therefrom targets the cylinder walls  4 , but which also does not come into contact with moving elements of the engine. 
         [0046]    In particular embodiments, the oil squirter  152  in each cylinder  2  is configured so at least two jets or sprays of oil are provided. The oil squirter also is arranged within the cylinder so that these sprays or jets of oil target two areas of the cylinder walls. In yet more particular embodiments, the oil squirter  152  is configured and arranged so that a lower portion of the cylinder  2  (e.g., the lower third of the cylinder) in the piston thrust area and the piston anti-thrust area are targeted by the at least two jets or sprays of oil. In yet further embodiments, the oil squirter  152  is fed oil from the cylinder block primary oil gallery  130 . The direction of these sprays or jets of oil are depicted in  FIGS. 3 and 4 . 
         [0047]    Now with reference also to  FIGS. 5-7 , each squirter  152  is affixed to the cylinder block  102 , by a fitting  154 , which fitting in one embodiment is a non-regulated bolt  154   a  ( FIG. 5 ) as is known to those skilled in the art or in another or alternative embodiment, the fitting is an internal pressure regulated bolt  154   b  ( FIG. 6 ) as is known to those skilled in the art. In either embodiment, the fitting  154 ;  154   a,b  receives a flow of oil from the main gallery  130  ( FIG. 3 ) as indicated in  FIGS. 5 and 6 . In the case where an internal pressure regulated bolt  154   b  is used, the oil is delivered to the squirter when the pressure of the oil from the main gallery exceeds a predetermined value. In the case where a non-regulated bolt  154   a  is used, the delivery or flow of oil to the oil squirter  152  and spraying therefrom can vary due to changing operating conditions of the reciprocating engine that affect oil pressure. 
         [0048]    In further aspects of the present invention, such an oil squirter  152  includes a body  160 , a first member  162  having two operable ends  163   a,b  and a second member  164  also having an operable end  165 . In particular embodiments, the first and second members  162 ,  164  are joined to each other using any of a number of techniques known to those skilled in the art so that the operable ends  163   a ,  165  of the first and second members form nozzles from which the oil is sprayed. Such joining of the first and second members forms a sub-assembly. The other operable end  163   b  of the first member  162  is joined to a mating connection or outlet  161  of the body  160 . In more particular embodiments, the first and second members are tubular metal members. In yet more particular embodiments, the second member  164  is joined to the first member  162  by brazing and the other operable end  163   b  of the first member is joined to the body outlet  161  also by brazing. 
         [0049]    In yet further embodiments, the first and second members  162 ,  164  are joined to each other so that the operable ends  163   a ,  165  of the first and second members are arranged so as to be at an angle with respect to each other. In more particular embodiments, the angle is such that one of the operable ends causes the oil spray or jet to be in the direction of the lower portion of the cylinder  2  (e.g., the lower third of the cylinder) in the piston thrust area and so that the other of the operable ends causes the oil spray or jet to be in the direction of the lower portion of the cylinder  2  (e.g., the lower third of the cylinder) in the piston anti-thrust area. In an illustrative embodiment, the operable ends  163 ,  165  are arranged so as to be essentially orthogonal to each other when the first and second members are joined to each other. In yet another illustrative embodiment, the angle is 90 deg.±5. 
         [0050]    In further embodiments, the first member  162  is configured so that a centerline of the operable end  163  is at an angle to the centerline of the other operable end  163   b  of the first member that is secured to the body outlet  161 . In an illustrative embodiment, the first member  162  includes a bend located between the body outlet  161  and the operable end  163   a  so that the operable end  163  is at such an angle. The angle is established so that the oil squirter  152  is displaced from the moving elements internal to the cylinder block such as the structure forming the crankshaft  120  and the connecting rod  112 . 
         [0051]    In further embodiments, the internal structure of at least the operable ends  163 ,  165  of the first and second member  162 ,  164  are established so that the oil flowing or spraying from the ends is generally sufficient for purposes of lubrication. In more particular embodiments, the internal structure is established so that the flow from each operable end is approximately the same or equalized. In more particular embodiments, the internal structure is established so that the flow from each operable end is optimized for the region(s) being targeted. 
         [0052]    As the first member  162  is generally less resistive to the flow of the oil as compared to the second member  164 , the operable end  163   a  of the first member is configured so as to increase the resistance to flow such that the first member&#39;s resistance is about the same as or greater than the flow resistance presented by the second member  164  and its associated operable end  165 . In this way, a more favorable pressure differential is established so that the outputs from the two nozzles or operable ends are at or about a similar value or equalized. 
         [0053]    In yet further embodiments and with reference to  FIG. 8 , the oil squirter  252  is configured so as to include a proximal member  262  and a distal outlet member  264  having an inlet  263   a  connection and two outlets  263   b,c . One end  263   b  of the proximal member  262  is coupled to the body outlet  161  as described above for the other operable end  163   b  of the first member  162  and the other end  263   a  of the proximal member  262  is coupled to the inlet connection  267   b  of the outlet member  264 . In this way, oil is fed through the proximal member  262  to the outlet member  264  much the same way as through the first and second members  162 ,  164  so that the oil exits through the outlets  263   b,c  and is directed to the cylinder walls  4  as described herein. 
         [0054]    Referring now to  FIG. 5 , and as indicated above, the illustrated oil squirter includes a non-regulated bolt  154   a  such as a banjo-style bolt that consists of a multiplicity of intersecting cross-drillings to establish a flow path between the oil flowing from the main gallery to the body  160 . As is known to those skilled in the art, in a banjo-style of bolt, the oil flows into an internal passage and thence out through the cross-drillings to an outer passage that encircles the internal passage. The oil in the outer passage flows to the body  160 . 
         [0055]    Referring now to  FIG. 6  and as indicated above, the illustrated oil squirter includes an internal pressure regulated bolt  154   b . In an exemplary illustrative embodiment, such an internal pressure regulated bolt includes a movable member  170  or piston, a spring member  172  and a stop  174 . The stop  174  abuts one end of the spring and is connected to the bolt so that a force acting on the other end of the spring causes the spring to compress. The movable member  170  abuts the other end of the spring  172  such that a force pushing against the movable member towards the spring causes the spring to compress. In use, the pressure of the oil coming from the main gallery acts on the movable member  170  and thus causes compression of the spring  172 . In this way, when the oil pressure exceeds a predetermined value, the spring  172  is compressed sufficiently that the movable member  170  moves past the cross-drillings thereby allowing the oil to flow into the outer passage and thence to the body  160 . 
         [0056]    In yet further embodiments, the block of such a reciprocating engine is configured so as to include 4 cylinders, 6 cylinders, 8 cylinders, 10 cylinders and 12 cylinders, and where the number of pistons corresponds to the number of cylinders. Such cylinders are arranged in the reciprocating engine so as to be inline, slanted, form a V, or arranged in any of a number of ways as one known to those skilled in the art. 
         [0057]    In yet further embodiments, the reciprocating engine is a four-stroke internal combustion engine or a two-stroke internal combustion engine. 
         [0058]    Although a preferred embodiment of the invention has been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims. 
       INCORPORATION BY REFERENCE 
       [0059]    All patents, published patent applications and other references disclosed herein are hereby expressly incorporated by reference in their entireties. 
       EQUIVALENTS 
       [0060]    Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents of the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.