Abstract:
An internal combustion engine connecting rod, having an embodiment defining a hollow beam member and a process of manufacture are disclosed. The improvement substantially reduces beam tensile and compressive stress levels through application of elliptical and convex segment profile beam sections, conserving reciprocating and rotating connecting rod weight required in high performance engine applications.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
       [0001]    This is a continuation-in-part of pending U.S. patent application Ser. No. 10/079,150 filed Feb. 20, 2002, titled Engine Connecting Rod for High Performance Applications and Method of Manufacture. The benefit of U.S. Provisional Patent Application Ser. No. 60/270,279, filed Feb. 22, 2001, is claimed. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to the field of high performance internal combustion engines pertaining to a connecting rod having a Hollow Beam construction providing a lighter and stronger connecting rod beam member, accomplished by originated elliptical type and eccentric circular segmented walled cross-sections. 
         [0004]    2. Description of Background Information 
         [0005]    Hollow connecting rods have a history dating back to early automotive engines of the 1920&#39;s. Particularly, achieving notoriety in high performance engines. In the mid 1960&#39;s the Meyer and Drake, “Offy” racing engines were phased out of use at the Indianapolis 500 mile races after over 20 years of reliable winning performance using hollow connecting rods. Since then, numerous patents have been awarded for hollow connecting rod inventions based on improvements to the original and basic features of historically known hollow beam connecting rods. Beam features such as a round hollow tube or having elongated tubular cross-sections and inserts to close the hollow beam cavity remain as the bases utilized for patented improvements. 
         [0006]    In the field of hollow connecting rods patents generally are for beam inventions applied to casting processes and not specifically for high performance or racing. Hollow connecting rods having cast cylindrical tubular beam members being disclosed in, for example, U.S. Pat. No. 5,140,869 to Mrdjenovich, et al (1992). This invention, a casting disclosure for an original and improved hollow beam casting is based on known hollow beam elements. 
         [0007]    Another invention for making a hollow beam member is based on having very wide spacing of the beam sides by means of longitudinal arc sides being tangent to piston pin bore and crankshaft bores (beam side being spaced each side of each bore). Including long cavity closing inserts extending between the longitudinal arc sides. U.S. Pat. No. 3,482,467 to Volkel (1969), the beam member is described and patented to have the side walls formed as a full arc inner surface “tangent” to bores of the piston pin (first bore) and the crank-shaft journal connection (second bore). This requires that the hollow cross-section major axis width be excessive creating a poor load force beam structure and that cavities be sealed with a very long insert at the crankshaft end that is without support to react high compressive peak forces; as high as 17,000 lbs. during the power stroke. A potential for bearing distress results due to the long unsupported span. The cavity closing insert being thin has potential for deflecting under power force. Deflecting only 0.002 inch will close bearing lubrication clearance, leading to failure. Volkel by patent claiming the inner wall “tangent” to the piston pin bore and outer wall “tangent” to outer wrist-pin boss diameter, and claming wall thickness between inner and outer arcs to be made large as possible at lower end adds wasted mass at the journal area beam sides, the wrong place for strength. Two conditions make Volkel&#39;s connecting rod unsuitable for high performance use and different then the present invention. (1) Volkel created a massive lower thick wall, making the rod heavier with mass questionably offset away from the force axis by the pronounced arc inner sidewalls “tangent” to both bores. The “tangent” sidewalls being ether side of the journal bore is alarming because the load force is directed in line with the longitudinal axis is not recognized, Also disturbing is the long sealing insert essentially is without bearing support structure. (2) Very thin wall sections at the wrist-pin boss and sharp corners invite high stress concentration areas. Stress concentrations are areas were stress forces collect due to material shape and mass affecting load path. Generally stress concentrations generate higher stress level values and problem areas. Volkel&#39;s invention is an investment casting. In order to be manufactured compromises with strength, mass and configured form were made. Volkel&#39;s invention disclosed a very different way to make a hollow beam noticeably different in form function and particularly in claims than the present invention disclosed herein. 
         [0008]    Another invention improvement for making a hollow beam is also based on long recognized approaches, that being elongated cross-section, in direction of crankshaft rotation. Disclosed is a method to make the hollow beam cross-section by using formed thin sheet metal to close the hollow beam and cap cavities. U.S. Pat. No. 5,370,093 to Hayes (1994) requires fabrication from costly preformed sheet metal using multiple piece joined assembly. The multiples thin sheet metal walls, welded into an assembly have limited load capacity and stress distribution, not considered appropriate for high performance applications; where high strength alloy steel and forgings are an important requirement. This is another patent noticeably different in form function and particularly in claims than the present invention disclosed herein. 
         [0009]    Reviewing the work of Volkel and Hayes and others, they do not address the objectives or distinctly disclose beam member elements and particularly elliptical profile specification of the present invention. This invention improvement discloses means for lowering stress level concentrations and improved force flux flow distribution from wrist-pin boss to crank-shaft boss. Disclosed is a unique minimal cross-sectional beam having elliptical form profiles providing area and mass improving compressive, tensile and eccentric force load capability over previous patented hollow connecting rods reviewed here, in archives and high performance connecting rods being manufactured. 
       SUMMARY OF THE INVENTION 
       [0010]    In one form of this invention there is provided a connecting rod for an internal combustion engine including a hollow beam member. The hollow beam connecting rod includes a piston pin bearing boss and crankshaft bearing boss elements. The boss elements are typical for high performance “racing” engine requirements that have configuration eliminating stress concentration, and providing force flux pathways to minimize stress levels and provision for high strength alloy steel, features generally lacking in prior art. The first end of the improved hollow beam member is joined to a high performance piston pin bearing boss element through a first curved region. The second end of the hollow beam member is joined to a high performance crankshaft bearing boss through a second curved region. The primary improvement is a hollow beam member formed by projected elliptical profile cross-sections on projection planes located at the beam member first end and the second end and centered on the longitudinal beam axis. The walls of the hollow beam member are defined preferably by elliptical outer and defined inner cross-section profiles inline, projecting direct “straight” beam walls from the first to the second elliptical cross-section projective plane. Avoiding the tangent beam sidewalls of Volkel. Sidewalls have a minimal required thickness and cross-section length increase in the major axis direction (direction of crankshaft rotation) than in the minor axis direction. Profiles embody a disclosed “ratio” system specifying wall thickness and profile cross-section major and minor axis length. In another form of the ellipse a “prolonged ellipse” also known as a “stretched ellipse” is provided by increasing the eccentricity (length) in the major axis. 
         [0011]    In accordance with another form of the invention there is provided a hollow beam member having variant cross-section profiles. The connecting rod includes a piston pin bearing boss and a crankshaft bearing boss as previously described. The cross-section profile of the hollow beam member first end and the second end being convex-segment cross-section profiles. Disclosed as a closed plane of curved segments (fixed radius arc segments) joined, intersecting as disclosed herein. The hollow beam member walls are thicker and beam length longer in the major axis direction (in plane of crankshaft rotation) than in the minor axis direction. A ratio system specifies profiles wall thickness and beam width. In another form of the convex profile a “prolonged convex profile” is provided, also known as a “stretched convex profile” provided by increasing the eccentricity (length) in the major axis. In accordance with another form of this invention there is provided a hollow beam member cross-section profile first end and the second end outer profile being elliptical or convex cross-section profiles. The inner profile embodies a circular fixed radius arc bore. 
         [0012]    The present invention provides a connecting rod comprising a hollow beam member of near minimum cross-section area and mass achievable. It is preferred that this is accomplished by precise beam wall cross-sections having elliptical or convex segment cross-section profile formation configured to a beam member column structure, having specific profile sidewall thickness and width ratios. The disclosed beam column form directs compressive and tensile forces centered about the longitudinal axis of load force path from piston pin to crankshaft journal, improving and “keeping the load path inline” and in-close proximity to the longitudinal axis. Thus efficiently distributing stress concentration throughout the connecting rod beam member. The embodiment potential is elimination or minimizing stress concentrations thus lowering high peak stress levels. Resulting in reliable performance at high engine RPM (Revolutions Per Minute) and improved fatigue life. This is important over prior art because weight reduction reduces mass inertia forces further lowering stress levels. Placement of beam defining cross-sections and section profile are defined with a ratio method to facilitate design and analysis of hollow beam connecting rod manufacturing. Materials, especially high strength alloy steel and forgings (180,000 to 220,000 psi) are “required” for the high performance engine connecting rod embodiments of the present invention. This requirement is not provided by noted prior art; being casting and sheet stock construction. 
         [0013]    The primary objective of providing lower stress levels and lower reciprocating weight is to reduce inertia forces. Inertia forces affect engine performance and increase stress in connecting rods. Hollow rod beam weight reductions of 45 to 60 grams over competing solid beam connecting rods have occurred in designs disclosed herein. Reduction of 45 grams of reciprocating weight will reduce peak inertia force by about 400 pounds at peak RPM, determined in studies. Performance is improved by increasing compressive force by 400 pounds on the piston during the power stroke. This is possible because inertia force (400 lbs.) must be overcome during the early part of power stroke by combustion pressure to push the piston during the power stroke. Thus imparting 400 lbs. gain in force to crankshaft rotation, a performance gain provided over prior art. 
         [0014]    Another objective is to provide an aerodynamic shape to reduce effects of rod contact with the ambient oil particle environment and air occurring within an engine at high RPM. 
         [0015]    An improvement shown in one embodiment of this invention is a new connecting rod beam member cross-section being an ellipse form. The objective being accomplished by varying cross-section profile shape and directional dimensions to meet requirements of stress analysis facilitated by embodiment of a ratio system specifying beam wall thickness and beam section cross-section major axis length. The process provides cross-section being elliptical profiles and geometric convex-segment profiles on finite projection planes to form and project precise beam member column form. 
         [0016]    An improvement of one embodiment of this invention is having a procedural embodiment to define and locate profile cross-section forms on projection planes centered on the beam longitudinal axis to project the connecting rod beam member surface form. A further purpose is to reduce the number of elements required to define a connecting rod beam to a few cross-section profiles, preferably two profiles placed on the beam longitudinal axis. The beam form disclosed using projection planes particularly facilitates connecting rod design using computer programs. This objective simplifies and facilitates accurate and analyzed connecting rod design. Computer programs which may be used are Computer Aided Design (CAD), Finite Element Analysis (FEA) and Computer Numerical Controlled (CNC) machining. Another advantage of the improvements disclosed and claimed herein is facilitated design and files computer generated and transferred by electronic means such as E-mail directly to CNC manufacturing machines and facilities. 
         [0017]    An advantage of this invention is the embodiments are applicable for casting manufacturing processes for conventional connecting rods using the teachings of the present invention. Beam member wall thickness and dimensions being adjusted for casting material strength being the change. 
         [0018]    An improvement shown in one embodiment of this invention is having a reliable connecting rod oil transfer tube from the crankshaft region to the piston pin bore. Beam movement and deflections would stress a rigidly fixed oil transfer tube installation of prior art. The oil tube shown provides a transfer tube that is compliant to bending, flexing, and to the tensile or compressive dynamic engine forces. The oil tube compliance is accomplished by an improved beam cavity sealing closure tapered plug that provides a recess accommodating O-Ring seals. The tube is sealed from leakage and remains compliant to movement forces at the O-ring connection. The upper end, being secured fixed to the piston pin boss. The tube is an optional provision and is not required or used in all applications. 
         [0019]    An improvement of one embodiment of this invention is a new application to provide a connecting rod bearing cap alignment embodiment to provide a more rigid alignment connection. This may be accomplished by machined sleeves, circular extending above the connecting rod cap surface and extending around the cap connection bolts. The sleeves register into mating bored recesses in the rod journal connection providing an accurate fitting cap to rod assembly. Previous sleeves in common use being separate elements pressed into the bearing cap, resulting in the cap being bored for sleeve installation weakening the structure and being compliant, not a rigid connection. 
         [0020]    Other objectives and advantages of the present invention will become apparent from the following descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The drawings constitute a part of this specification and include the embodiment of this invention. 
           [0022]      FIG. 1  is a front elevation view of a connecting rod assembly illustrating one embodiment of the connecting rod of the present invention. 
           [0023]      FIG. 2  is a side elevation view of the connecting rod of one embodiment of the present invention. 
           [0024]      FIG. 3  is a longitudinal section view of the connecting rod of one embodiment of the present invention taken along the cut line  3 - 3  of  FIG. 2 . 
           [0025]      FIG. 4  is a transverse sectional projection plane view of the connecting rod of one embodiment of the present invention taken along the cut line  4 - 4  of  FIG. 1 . 
           [0026]      FIG. 5  is a transverse sectional projection plane view of the connecting rod of one embodiment of the present invention taken along the cut line  5 - 5  of  FIG. 1 . 
           [0027]      FIG. 6  is a front elevation view of the connecting rod assembly of another embodiment of the present invention for purpose of illustrating transverse sections having prolonged ellipse plane form. 
           [0028]      FIG. 7  is a transverse section view of ellipse profile application to  FIG. 6  before being prolonged. 
           [0029]      FIG. 8  is a transverse section projection plane view of the connecting rod of  FIG. 6  taken along the cut line  8 - 8  of  FIG. 6 . 
           [0030]      FIG. 9  is a transverse section projection plane view of the connecting rod of  FIG. 6  taken along the cut line  9 - 9  of  FIG. 6 . 
           [0031]      FIG. 10  is a front elevation view of the connecting rod assembly of another embodiment of the present invention for purpose of illustrating transverse section having convex-segment profile form. 
           [0032]      FIG. 11  is a transverse projection plane view of the convex-segment profile of  FIG. 10  taken along cut line  11 - 11  of  FIG. 10 . 
           [0033]      FIG. 12  is a transverse projection plane view of the convex-segment profile of  FIG. 10  taken along cut line  12 - 12  of  FIG. 10 . 
           [0034]      FIG. 13A  is a front elevation view of the connecting rod assembly of another embodiment of the present invention for purpose of illustrating transverse section having ellipse outer profile form and radial circular inner centered bore.  FIG. 13B  is a side elevation view of  FIG. 13A  illustrating partial view of inner profile form. 
           [0035]      FIG. 14  is a transverse projection plane view of the ellipse outer and radial inner profile of  FIGS. 13A and 13B  taken along cut line  14 - 14  of  FIG. 13A . 
           [0036]      FIG. 15  is a transverse projection plane view of the ellipse outer and radial inner profile of  FIGS. 13A and 13B  taken along cut line  15 - 15  of  FIG. 13A . 
           [0037]      FIG. 16  is a partial front elevation view of the connecting rod view  FIG. 1  illustrating cavity closure plug. 
           [0038]      FIG. 17  is a plane and side view of cavity closure plug from view  FIG. 16 . 
           [0039]      FIG. 18  is a partial front elevation view of the connecting rod view  FIG. 13A  illustrating cavity closure plug. 
           [0040]      FIG. 19  is a plane and side view of cavity closure plug from view  FIG. 18 . 
           [0041]      FIG. 20  is a graphic illustration designation of the ellipse profile geometry defining one form of the present invention. 
           [0042]      FIG. 21  is a graphic illustration designation of a two segment radius convex-segment profile geometry defining one form of the present invention. 
           [0043]      FIG. 22  is a graphic illustration designation of a three segment radius convex-segment profile geometry defining one form of the present invention. 
       
    
    
       [0044]    RATIO TABLE 1: “Ratios for wall thickness and profile length at second cross-section, major axis”. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0045]    A general portrayal of disclosed hollow connecting rod embodiments being presented that are applicable to FIG&#39;S.  1 ,  6 ,  10  and  13 . With reference to  FIG. 1  and  FIG. 2  of the drawings there depicted a hollow connecting rod  10  for use in high performance engines. The connecting rod  10  comprising an elongate longitudinal column beam member  11  having two opposite ends  12 ,  13  each forming a one-piece beam segment. There merging from first end  12  are arcuate side surface  14  flanks, joining piston pin bearing boss  15  having a round bearing surface  16 , for cooperating with a piston pin (not shown). At beam member  11  the opposite second end  13  is a crankshaft bearing boss  17 , having arcuate side surface  18  flanks, including a round bearing surface  19  for cooperating with a bearing insert and crankshaft journal when secured thereto (not shown). Crankshaft bearing boss  17  having bolt boss  20 ,  21 , secured thereto bearing cap  22  by bolts  23 ,  24 . As noted in  FIG. 1 , hollow beam member  11  employs a system of cross-sections; consisting of cut lines  4 - 4  and  5 - 5  including a first cross-section projection plane FP and second cross-section projection plane SP on which cross-section profiles that define the hollow beam member  11  are originated. Beam member  11  is projected between the originated cross-section profiles created on the cross-section projection planes FP and SP. Each cross-section is centered on connecting rod longitudinal axis  43 . The beam member  11  form is projected from a first cross-section profile  51  to a second cross-section profile  52 , illustrated by  FIGS. 4 and 5 , The projected cross-section profiles  51  to  62  produce a beam member  11  having a straight line sidewall  50 . Preferably only two cross-section projection planes are required. Further details of profiles being disclosed after completing disclosure of  FIG. 3  inner structure embodiments that follows. 
         [0046]    Beam member  11  column Inner structure description being presented, with reference to  FIG. 2 , a longitudinal section view is taken along cut line  3 - 3  to disclose the inner structure of the connecting rod of this invention, best shown in  FIG. 3  as follows. The piston pin bearing boss  15  provides an optional oil passage tube  27  embodiment consisting a first passage  25  which extends longitudinal on axis  43  with respect to the beam member  11  to the round piston pin bearing surface  16 . Viewing the opposite end, within the crankshaft bearing boss  17  is a second passage  26 , extending to the round bearing surface  19 . Continuing with  FIG. 3  thereto passage  25  and  26  is secured oil passage tube  27  for the purpose of transferring oil from second passage  26  to first passage  25 . Oil passages tube  27  being fixed and secured at first passage  25 . Oil passage tube  27  being sealed at second passage  26  thereby a unique Oil packing seal  28  embodiment providing for axial motion differential between oil passage tube  27  and the connecting beam member body, thereto eliminate interacting movement between beam member  11  and oil passage tube  27 . Oil passage tube  27  assembly embodiment is an optional feature required for certain applications. 
         [0047]    Inner beam elements at crankshaft connection being continued. Referring to  FIG. 3 , the elongate hollow beam member  11  there being hollow cavity  48  with wall  50  having cross-section inner profiles  42  and  45  ( FIGS. 4 and 5 ) projected from first cross-section projection plane FP profile to second cross-section projection plane SP, defining hollow cavity  48 , sidewall  50 . Cavity  48  ends approximately 0.150 inch above first projection plane FP having substantial end radius  55 . This is a specific embodiment required to avoid any sharp corners or edges that concentrate stress leading to fatigue cracking. Now continuing in  FIG. 3 , the cavity  48  of connecting rod member  11  there being an closure tapered plug  29  embodiment fitted to tapered beam wall  30  for the purpose of sealing beam cavity  48 . The closure tapered plug  29  having partial thin wall, a compliant segment to relieve compressive pressure force at closure tapered plug  29  outer edge. The closure tapered plug  29  is bonded or fusion welded  31  in place. Turning to  FIG. 16  and  FIG. 17  illustrating a partial view of crankshaft bearing boss  17  and closure tapered plug  29  embodiment; having a preferred taper TP of 3 to 5 degrees. A predetermined depth HD ratio sized to eliminate deflection issues for hollow connecting rod configurations herein; depth ratio HD preferred to be 35% to 50% the width WD of closure tapered plug  29 . Illustrated is a ratio of 36%. The disclosed purpose of the taper is to direct axial force on closure tapered plug  29  by tapered “wedging” that force into side walls of crankshaft bearing boss  17 , eliminating deflection at closure tapered plug  29 ; which is a problem with noted prior art. With reference to  FIG. 1 , the bolts  23 ,  24  extend through bolt boss  20  and  21  from bearing cap  22  into threaded bores. Returning to  FIG. 3 , threaded bores  32  and  33  are illustrated. The bolts  23 ,  24  have been omitted from  FIG. 3  for clarity to disclose the embodiment whereby bearing cap  22  assembles and therein is aligned to crankshaft bearing boss  17  as follows. Alignment receptacle  34  and  35  are circular machined into bolt boss  20  and  21  concentric with bolt and thread axis having a depth to accept matching extended machined circular alignment sleeves  36  and  37  machined onto the mating surface of the bearing cap  22 . Note that  FIG. 3  illustrates cut lines from  FIG. 1  in parentheses. The purpose is to indicate facilitating reference when viewing content of  FIG. 3  related to cut lines ( 4 )-( 4 ) and ( 5 )-( 5 ). 
         [0048]    Prior to continuing with profile description, the tensile and compressive force conditions improved by the hollow beam connecting rod beam structure is described. Referring to  FIG. 1 , tensile and compressive force conditions are described that are provided for by the invention embodiments. Note center longitudinal axis  43  between first reference point, RP 1  and second reference point RP 2 ; indicating the linear tensile T force and compressive C force. Vector FV represents force action on disclosed connecting rod structure. Tensile force T results from piston and piston pin inertia mass effect on the piston assembly upward movement. Compressive force C results from combustion force of the power stroke on the piston assembly downward movement. Tensile (inertia force) force of 7,200 lbs. and compressive force of 17,100 lbs. react to piston pin bearing surface  16  and bearing surface  19  through column beam member  11  at reference points RP 1  and RP 2 , are typical force examples. Hollow rod beam member  11  embodiments provide a preferred column structure having cooperating straight sidewall  50 , aligned under and line with piston pin boss  15 , remaining in close proximity with the noted axial force vector FV being collinear with longitudinal axis  43 . 
         [0049]    Continuing disclosure of elliptical cross-section profile embodiment for beam member  11  being presented. The profile development means defining profiles and alignment that follows is applicable to other beam member  11  embodiments disclosed herein. Cut-lines  4 - 4  and  5 - 5  therein indicating cross-section locations. Illustrated in  FIG. 4 , the first cross-section profile  51  and  FIG. 5  the second cross-section profile  52 . The beam member profile cross-section and positioning feature of this invention there being disclosed, beginning with  FIG. 4 , the first cross-section profile  51  axis convention being disclosed; beginning with axis X-X of first cross-section profile  51 , the axis X-X is in the direction of crankshaft plane of rotation  38  and is the major (long) axis of cross-section profile  51 . Axis Y-Y is in the direction normal to crankshaft rotation and is the minor (short) axis of cross-section profile  51 .  FIG. 5  identifies the second cross-section profile  52 . Note axis X-X is defined as the major axis and axis Y-Y is defined as the minor axis. Both cross-section profiles  51  and  52  are centered on longitudinal axis  43 . 
         [0050]    First cross-section profile  51  and second cross-section profile  52  formations being disclosed. Returning to  FIG. 4 , illustrating first cross-section profile  51 . Elliptical type outer profile  41  and inner profile  42  define the beam member  11  and sidewall  50  thickness at first cross-section profile  51 . Specified wall thickness  39  indicated on the minor Y-Y axis and specified wall thickness  40  on major axis X-X. Note that wall thickness increases, beginning from the minor axis Y-Y at thickness  39  changing gradually to the major axis X-X at thickness  40 . 
         [0051]    Continuing now with the second cross-section profile  52 , referring to  FIG. 5  location of second cross-section profile  52  elliptical type having outer profile  44  and inner profile  45  defining beam member  11  and sidewall  50  thickness at cross-section profile  52 . Sidewall thickness  46  being on the minor Y-Y axis and wall thickness  47  being on major axis X-X. Illustrating longer outer profile  44  X-X length and increased wall thickness  47  than first cross-section  51 , wall thickness  40  on the major axis profile. The longer major axis and increased sidewall thickness  47  being required accommodating higher bending moments occurring in second cross-section profile  52  area, plane of crank-shaft rotation. Cross-section profiles  51  to  52  projected sidewall thickness and beam length in the X-X and Y-Y axis are defined embodying “ratios” of cross-section profiles  51  and  52 , to follow. 
         [0052]    Embodiment to establish cross-section profile sidewall  50  thickness and beam X-X and Y-Y length being provided by means of “ratios” that optimize efficient beam member  11  column structure for close inline support of noted direct acting force vector FV, tensile force T and compressive force C. A convenient control system employing a first “ratio” multiple of first ellipse cross-section profile  51  sidewall thickness  39  and  40  defining second profile  52  sidewall thickness  46  and  47 . And, a second “ratio” multiple of first ellipse  51  major and minor axis length defining second profile  52  major and minor axis length. Ratios are derived from analysis of connecting rod designs conforming to the present invention embodiments. 
         [0053]    Ratio application method disclosed as follows is applicable to beam member  11  of FIG&#39;S.  1 ,  6 ,  10  and  13 . The ratio application is illustrated in FIG&#39;S.  4  and  5 . Wherein the second cross-section profile  52 , profile major axis thickness  47  is derived by multiplying first cross-section profile  51 , sidewall thickness  40  by a first ratio range of 1.00 (being a ratio of 1 to 1) to 5.00 (being a ratio of 5 to 1). And, second cross-section profile  52 , major axis length derived by multiplying cross-section profile  51  major axis length by a second ratio range of 1.00 (being a ratio of 1 to 1) to 1.50 (being a ratio of 1.50 to 1). Preferably the ratios for profile sidewall thickness  39  and  46  and length of cross-section profiles  51  and  52  is 1 to 1 in the minor axis, as illustrated, to accommodate design and manufacturing simplicity. Referring to Table 1, “Ratios for wall thickness and profile length at second cross-section, major axis” provides ratio application instruction to the preferred second cross-section major axis profile dimension requirements. And, is applicable to all hollow connecting rod beam member  11  herein. The minor axis profile thickness and length has a preferred ratio of 1 to 1. 
         [0054]    Continuing with disclosure of the elliptical form profile embodiment. The descriptive ellipse example disclosed herein being determined using the mathematical “Equation of the Ellipse”, as used in Analytical Geometry. Variations of the ellipse equation may be used to alter the radius of curvature and the cross-section elliptical profile to distribute mass to optimize the beam member stress levels and load efficiency. By example,  FIG. 4  the length dimension of the minor axis Y-Y may be significantly reduced making the beam cross-section with less length in the Y-Y direction, or the ellipse profile defined as a “flattened circle” as described in Mark&#39;s, Mechanical Engineering Handbook. Further stating, the ellipse may be “stretched” geometrically known in geometry as a “prolonged ellipse” on the major axis X-X. 
         [0055]    Formulas for ellipses may be found in mechanical engineering handbooks. Mechanical Engineers&#39; Handbook by Lionel S. Marks in general use provides formulas to develop various elliptical constructions applicable to this invention. The preferred method for ellipse form cross-sections development is the use of Computer Aided Design, CAD programs, creating an ellipse having the “Equation of the Ellipse” is simplified using CAD programs. These programs require input of only the major axis and the minor axis length dimensions. The program “Ellipse Icon” draw command then automatically constructs the ellipse effortlessly using “Equation of the Ellipse” as illustrated in  FIG. 4  and  FIG. 5 . Referring to  FIG. 20 , the ellipse geometric representation of the algebraic equation for the ellipse definition embodiment of the present invention is illustrated. Points P enclosed in a projective plane form the ellipse profile; such that the sum of the distances from two fixed “focus” F 1  and F 2  to a point P is a constant. The embodiment defines the major axis MA length as the constant. 
         [0056]    Continuing with disclosure of the cross-section profile embodiment improvement by a “second means” of construction for beam member  11 . A preferred method improves the elliptical profile strength in the X-X direction by a slight profile distance length increase of mass placement at the major axis end; “stretching the X-X profile slightly for certain preferred applications. 
         [0057]    Continuing with  FIG. 6  disclosing “second means” construction for beam member  11  having a cross-section elliptical profile stretched in the major axis and known as a “prolonged ellipse”. Certain high performance engines require more mass at the ends of a longer X-X major axis for strength. The “second means” is a preferred improvement to the ellipse profile disclosed by  FIGS. 4 and 5 ; providing means to narrow the minor axis and increase the major axis length. The ellipse improvement is provided being “stretched”, known by the geometry term as a “prolonged ellipse”. Defined by wikipedia.org encyclopedia: “An ellipse may be uniformly stretched along any axis, in or out of the plane of the ellipse, and it will still be an ellipse”. Beginning with  FIG. 7 , disclosure of a true ellipse, having uniform ellipse section  58  each side of axis Y-Y, centered on axis X-X, is illustrated before stretching into a prolonged ellipse.  FIG. 8  illustrates the first cross-section prolonged ellipse  49  profile taken at cut lines  8 - 8 . Depicted stretched into a prolonged ellipse having a predetermined increased major axis length at profile sidewall segment  53  and increased sidewall thickness  54 . By example, the  FIG. 7  ellipse is uniformly stretched 12% into the prolonged ellipse  49  of  FIG. 8 . Profile sidewall segment  53 , being centered on axis Y-Y. 
         [0058]      FIG. 9 , continues disclosing “second means” disclosing the second cross-section prolonged ellipse  56  profile taken at cut lines  9 - 9  illustrate ellipse by example uniformly stretched 26% at sidewall segment  53  bring centered on axis Y-Y. Embodiment of ratios previously used to define beam member  11  are used to prescribe second cross-section sidewall thickness  57  and major axis profile  56  beam length. Referring to “Ratio Table 1” application of ratios for sidewall thickness and profile length at second cross-section, major axis is disclosed for “second means”. The method used to determine first and second cross-section length dimension is preferred accomplished using FEA analysis to evaluate stress levels, patterns and stress concentrations, then making dimensional adjustment to define desired stress levels. 
         [0059]    Continuing with FIG&#39;S.  10 ,  11  and  12  disclosing “third means” construction for beam member  11  having a first “convex-segment” profile  59  and second prolonged convex-segment second profile  63  embodying axis alignment convention disclosed by  FIGS. 1 and 6  for elliptical and prolonged ellipse cross-section profiles. Beginning with  FIG. 10  disclosure of the convex-segment beam profile embodiment is illustrated. Cut line  11 - 11  is first cross-section having first convex-segment profile  59  at  FIG. 11 . Convex-segment profile is a geometric construction embodiment developed to employ two intersecting radius elements for profile construction; a first radius for the minor axis Y-Y profile and a second radius for the major axis X-X profile. RAD # 1  is the first radius originating on each major axis end selected for the outer profile  60  major axis. RAD # 2  is the second radius originating on each minor axis end selected for the outer profile  61  minor axis. Construction of convex arc segments (RAD # 1  and RAD # 2 ) intersecting typical at CL positions; forming first convex-segment profile. The inner profile  66  is constructed as the outer profile providing required wall thickness  62  and  63   
         [0060]    Continuing with  FIG. 12 , the second cross-section convex-segment profile taken at cut lines  12 - 12  illustrates a prolonged convex-segment profile  63  produced by uniformly stretched major axis X-X of  FIG. 11  profile  59 . Increasing profile  59  major axis length by a ratio range of 1.00 to 1.50. Illustrated profile  63  having beam major axis length ratio 1.10, by example, resulting in 10% prolonged convex-segment profile  63 , and having centered segment  64  on axis Y-Y. The inner profile is constructed as the outer profile, except wall thickness  65  is established by Ratio Table 1. Prolonged centered segment  64  has preferred same thickness as wall thickness  62 . The illustrated second prolonged convex-segment profile  63  is dimensioned using ratios. Referring to “Ratio Table 1” application of ratios for wall thickness and profile length at second cross-section, major axis is disclosed for “third means”.  FIG. 12  illustrates wall thickness  65 =ratio 1.11. Profile  63  major axis length=ratio 1.10. 
         [0061]    Referring to  FIG. 21 , a geometric construction of the convex-segment profile definition of the present invention is illustrated. Consisting of two radius arcs, RAD # 1  one at each side center point CP on major axis MJA, at opposite points P 1  and RAD # 2  one each side of center point CP on minor axis MIA, at opposite points P 2 . Arc centers CEN # 1  is positioned on the major axis MJA, providing arc RAD # 1  at each P 1 . Arc RAD # 2  is positioned from point P 2  on minor axis MIA, extending through center point CP to pivot center CEN # 2  by construction line CL. The radii RAD # 2  from CEN # 2  intersect RAD # 1  P 1  at each arc joint AJ by construction lines CL 1  and CL 2 . The embodied procedure improves arc intersection symmetry. 
         [0062]    Continuing with  FIG. 13  A an B partial section views disclosing a “fourth” improvement defining beam member  11  embodying elliptical outer beam profile and providing inner profile  72  consisting a circular fixed radius arc inner bore. Beam member  11  outer profile is projected from projection plane cross-sections at cut lines  14 - 14  to  15 - 15  centered on longitudinal axis  43 .  FIG. 14  taken at cut lines  14 - 14  define beam member first cross-section elliptical outer profile  67  having wall thickness  68  on the major axis and wall thickness  69  on the minor axis.  FIG. 15  taken at cut lines  15 - 15  define second beam member  11  cross-section elliptical outer profile  70  having thickness  71  on the major axis and wall thickness  69  on the minor axis. Profile  67  and  70  wall thickness  69  are preferably equal. Ratios previously noted are applied to profile  67 . Referring to “Ratio Table 1” application of ratios for wall thickness and profile length at second cross-section, major axis is disclosed for “forth means”. Inner bore  72  ends above cut line  14 - 14  and is required to have large radius, preferably a full radius as shown at radius  73 . 
         [0063]    Continuing at  FIG. 13A , the partial section view discloses closure tapered plug  74 , a circular tapered plug cooperating with profile of the open cavity, bonded or fused  31  in place. Plug tapers preferred at 3-5 degrees distributing compressive forces wedging and distributing into the heavier crankshaft bearing boss  17 . Turning to  FIG. 18 , illustrated is a partial view of installed closure tapered plug  74  and separate view  FIG. 19 . A predetermined depth HD ratio sized to provide deflection resistance being disclosed. Depth HD preferred to be 35% to 50% the width WD of closure tapered plug  74 . Illustrated is a ratio of 48%. The disclosed purpose of the taper is to direct axial force on closure tapered plug  74  by “wedging” that force into side walls of crankshaft bearing boss  17  to eliminate force deflection at plug  74 . 
         [0064]    Referring to  FIG. 22  illustrated is a beam member  11  geometric cross-section profile embodiment provided for certain applications. Consisting of a convex-segment profile having 3 intersecting radius arc segments used to create a closed profile, preferably for outer cross-section profiles. The outer profile for beam member  11  of  FIGS. 13A  and B is an alternative preferred application for 3 intersecting radii convex-segmented outer profile; being illustrated in  FIG. 22 . RAD # 1  is an arc radius at each end length of major axis X-X. RAD # 2  is a arc radius at each end length of minor axis Y-Y. Arc center CEN # 1  is positioned on the major axis providing an arc having RAD # 1  at opposite points P 1 . And RAD # 2  is positioned on minor axis providing an arc having RAD # 2  at opposite points P 2 . Arc center CEN # 2  is positioned on minor axis providing arc RAD # 2  at opposite points P 2 . RAD # 3  intersects RAD # 1  to RAD # 2  from CEN # 3 . CEN # 3  being located by construction lines projected from end of arc intersecting segments AIJ through CEN # 1  and CEN # 2 , projecting and terminating at intersection CEN # 3 , providing RAD # 3  construction. The construction of intersecting arcs embodiment herein provides a preferable cross-section profile for certain applications, such as  FIGS. 13  A and B. RAD # 3  intersections are very close using the disclosed method, however not precise. Improved may be made by slight adjustment to CEN # 3   
         [0065]    The present invention embodiments consider use of computer programs to facilitate design of connecting rods using Computer Aided Design, CAD, in particular, 3 Dimensional, or 3D CAD programs and Finite Element Analysis, FEA. Connecting Rod cross-sections such as ellipses, elliptical forms can be generated using capabilities of CAD programs to facilitate cross-section profile development to accomplish connecting rod design of the present invention. 
         [0066]    The connecting rod of the present invention embodiments having profile form and ratios controlling beam member form is particularly suitable of being manufactured using aluminum connecting rods such as used in drag racing. Applying “ratios” for beam member as disclosed herein and adjusted for material tensile strength and characteristics is required. The herein embodied disclosure being fully applicable to aluminum connecting rods. Investment casting, powder forging or conventional casting procedures are applicable to the disclosed embodiments. As best seen in  FIG. 3  of this disclosure thereby illustrating that the connecting rod of this invention provides casting form, having capable casting draft in the Y-Y minor axis direction and casting parting lines through the X-X major axis. 
         [0067]    The hollow beam connecting rod being a “Closed Beam” hollow column is capable of higher load capacity over conventional “Open Beam” columns. Most conventional high performance connecting rods are H-Beam configuration, having open flanges in direction of crankshaft rotation. Mass is centered on the longitudinal and neutral axis, requiring more mass to accommodate column and bending loads. The H-Beam open flange edges are affected with stress concentrations. The hollow “Closed Beam” embodiment herein places mass a defined distance from the longitudinal and neutral axis, less material is required to accommodate column and bending loads. And, there are no free standing open edges. Reducing beam mass results in less reciprocating mass being accelerated by inertia forces at high engine speeds. The Engineering method used regarding the present invention is a proprietary developed process designed to be simple, being based on experience and assembled study and analysis data. Programs where engine dimensions and data, RPM and component weights are entered determine the force loads acting on the connecting rod and beam as the crankshaft rotates through an engine cycle. Primary forces determined are (1) Tensile loads including peak tensile load. (2) Compressive loads including peak load. (3) Bending force and related angles. A preferred method used to determine the value for noted “ratios” applied to disclosed cross-section profiles is to relate determined cross-section “moments of inertia” and “cross-section area” to a ratio range. Providing the highest moments of inertia in the X-X major axis being the objective for a ratio range. 
         [0000]    
       
         
               
             
               
               
             
               
             
               
               
             
               
             
               
             
               
             
               
             
               
             
               
             
           
               
                 RATIO TABLE 1 
               
               
                   
               
               
                 RATIOS FOR WALL THICKNESS AND PROFILE LENGTH 
               
               
                 AT SECOND CROSS-SECTION, MAJOR AXIS 
               
               
                   
               
             
             
               
                 First cross-section (upper) notation: 
               
             
          
           
               
                 Major axis sidewall thickness (W1) 
                 Minor axis sidewall thickness (W2) 
               
               
                 Major axis profile length (L1), 
                 Minor axis profile length (L2) 
               
             
          
           
               
                 Second cross-section (lower) notation: 
               
             
          
           
               
                 Major axis sidewall thickness (W3), 
                 Minor axis sidewall thickness (W4) 
               
               
                 Major axis profile length (L3), 
                 Minor axis profile length (L4) 
               
             
          
           
               
                 Second cross-section sidewall major axis thickness ratio: 
               
             
          
           
               
                 Sidewall thickness major axis ratio (STR) range = 1.00 (being ratio 1 to 1) 
               
               
                 to ratio 5.00 (being ratio 5 to 1) 
               
             
          
           
               
                 Second cross-section major axis profile length ratio: 
               
             
          
           
               
                 Major axis profile length ratio (PLR) range = 1.00 (being ratio 1 to 1) 
               
               
                 to ratio 1.50 (being ratio 1.50 to 1) 
               
             
          
           
               
                 Ratio Application Example: 
               
             
          
           
               
                 First major axis sidewall thickness W1 = 0.122 inch. 
               
               
                 Ratio STR applied = 1.29 
               
               
                 Second major axis sidewall thickness W3 = 0.122 * 1.29 = 0.157 inch 
               
               
                 Second major axis sidewall thickness increased to = 0.157 inch 
               
               
                 First major axis profile length L1 = 0.962 inch 
               
               
                 Ratio PLR applied = 1.155 
               
               
                 Second major axis profile length L3 = 0.962 * 1.155 inch = 1.111 inch 
               
               
                 Second major axis profile length increased to = 1.111 inch