Abstract:
A V-2 engine; with four valves per cylinder, dual overhead camshafts, offset cylinders, and a single crankpin crankshaft; that will fit onto the stock front and rear EVO crankcase mounts, the stock primary drive and crankshaft mounting locations, and within the frame rails of a stock size EVO chassis (whether OEM or aftermarket).

Description:
FIELD OF THE INVENTION  
       [0001]     This invention relates to an improvement in a two-cylinder V-type spark-ignition engine with overhead camshafts, generally called a dual overhead (DOHC) V-2 engine.  
       BACKGROUND OF THE INVENTION  
       [0002]     Around 1984 the Harley-Davidson Motor Company introduced the 1340 EVOLUTION® motorcycle engine (EVO), and Harley-Davidson continued to produce models that utilized the EVO engine until about 1999. Throughout this time period, there were also many aftermarket manufacturers that produced frames, engines and power transmission components suitable for use with the EVO platform.  
         [0003]     As with all engines, the original factory EVO engines have specific frame and power transmission mounting components and locations. Many aftermarket engine manufacturers produce their designs based on this EVO mounting configuration. As a result, these engines will fit as direct replacements for the original equipment manufacturer (OEM) equipment and there are no alterations to the frame or power transmission mounting components required.  
         [0004]     Because of the popularity of the EVO engine and the large aftermarket following that it has gained, the engine is arguably the most widely used platform for custom builders and performance enthusiasts.  
         [0005]     Accordingly, there is a need for aftermarket engines that will fit onto the stock front and rear EVO crankcase mounts and the stock primary drive and crankshaft mounting locations. These engines also must fit within the frame rails of a stock size EVO chassis, whether OEM or aftermarket.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention meets the above described need by providing a V-2 engine; with four valves per cylinder, dual overhead camshafts, offset cylinders, and a single crankpin crankshaft; that will fit onto the stock front and rear EVO crankcase mounts, the stock primary drive and crankshaft mounting locations, and within the frame rails of a stock size EVO chassis (whether OEM or aftermarket).  
         [0007]     The above and other features and advantages of the present invention will become manifest to those versed in the art upon making reference to the following description and accompanying sheets of drawings in which preferred structural embodiments incorporating the principles of the invention are shown by way of illustrative examples. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a side elevational view of a DOHC V-2 engine according to an embodiment of the present invention;  
         [0009]      FIG. 2  is a cross-sectional view taken along lines  2 - 2  of  FIG. 1 ;  
         [0010]      FIG. 3  is a rear elevational view of the engine of the present invention;  
         [0011]      FIG. 4  is a cross-sectional view taken along lines  4 - 4  of  FIG. 3 ;  
         [0012]      FIG. 5  is a side perspective view of the engine shown from the side opposite of the side shown in  FIG. 1 , with covers removed for clarity;  
         [0013]      FIG. 6  is a side perspective view of the linkage for the engine shown in  FIG. 5  with the covers, cylinders and cylinder heads removed for clarity;  
         [0014]      FIG. 7  is a view similar to  FIG. 6 , but shown from the opposite side;  
         [0015]      FIG. 8  is a side elevational view showing the cylinder configuration with the heads and cylinders removed for clarity;  
         [0016]      FIG. 9  is a top plan view of the components shown in  FIG. 8 ;  
         [0017]      FIG. 10  is a side elevational view showing the configuration for mounting the power transmission components to the engine;  
         [0018]      FIG. 11  is a bottom plan view showing the configuration for mounting the engine to the frame; and,  
         [0019]      FIG. 12  is a perspective view of a frame suitable for use with the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]     The following description is merely exemplary in nature and is in no way intended to limit the invention or its application or use.  
         [0021]     Referring to  FIG. 1 , there is shown a dual overhead camshaft (DOHC) V-2 engine according to an embodiment of the present invention. As shown the engine  10  is of the type suitable for mounting in a motorcycle frame such that the engine  10  has front cylinder block  13  disposed on the left hand side of the figure which corresponds to the front of the motorcycle and a rear cylinder block  16  disposed on the right hand side of the figure which corresponds to the rear of the motorcycle. The cylinder blocks  13  and  16  are configured at positions described in greater detail herein. The engine  10  has a crankshaft  19  that extends horizontally (normal to the page in  FIG. 1 ). The engine  10  includes a crankcase  22 .  
         [0022]     Turning to  FIG. 2 , the crankshaft  19  is rotatably mounted in the crankcase  22  and has longitudinal opposite end portions  25 ,  28  journaled on the crankcase  22 , respectively, via a pair of plain bearings (not designated). The end portion  25  of the crankshaft  19  projects outward from the crankcase  22  and forms a power take out portion of the engine  10 . The end portion  28  projects rearward of the crankcase  22  for a purpose described below.  
         [0023]     The crankshaft  19  has a longitudinal central portion forming a single offset journal or crankpin  31  to which two connecting rods  34  and  37  are attached side-by-side as indicated by arrow  40 . The crankshaft  19  is also provided with counterweights  43 .  
         [0024]     Turning to  FIGS. 3-4 , the cylinder blocks  13 ,  16  are attached to the crankcase  22  so that they are arranged at an angle to each other about the axis Ll (normal to the page in  FIG. 1 ) of the crankshaft  119 . The cylinder blocks  13 ,  16  have a mounting end  46  fitted in the crankcase  22 . The angle between the cylinder blocks  13 ,  16 , that is, the bank angle  47  is forty to fifty degrees and is shown at approximately 45 degrees in  FIG. 4 , although other bank angles are also suitable as will be evident to those of ordinary skill in the art. Also as will be evident to those of ordinary skill in the art, the cylinder blocks  13 ,  16  may be attached to the crankcase  22  by means of screws, stud bolts and nuts, or the like.  
         [0025]     The cylinder blocks  13 ,  16  are each provided with a multiplicity of cooling fins  50 . A mating surface  54  ( FIG. 10 ) of each cylinder block  13 ,  16  relative to the crankcase  22  is preferably set to be positioned near the endmost cooling fin  50 . As described in greater detail in connection with  FIG. 9 , the cylinder blocks  13 ,  16  are offset from each other in the axial direction of the crankshaft  19  (L 1 ) so that the connecting rods  34 ,  37  can be disposed side by side on the single crankpin  31 .  
         [0026]     The tops of the cylinder blocks  13 ,  16  are covered by cylinder heads  60  and  63 . On the right hand side of  FIG. 4 , the front cylinder head  60  is shown with a bank of cam operated valves  69  disposed thereon. Dual overhead cam shafts  72  and  75  operate four valves  69  for each cylinder. On the left hand side of cylinder head  60 , an intake port  76  is shown. The cam operated valve  69  shown on the left side opens on intake by means of cam  80  connected to cam shaft  75  to allow the fuel-air mixture to enter the combustion chamber. On the right hand side of the cylinder head  60 , an exhaust port  77  is shown. A cam operated valve  69  operated by cam  88  connected to cam shaft  72  opens and closes in order to allow the exhaust gases to exit from the cylinder at the end of the cycle. There are two intake valves and two exhaust valves for each cylinder. In  FIG. 4 , the second row of intake and exhaust valves are in alignment behind the valves shown and therefore are not visible. In  FIGS. 6 and 7  which are discussed in greater detail below, all four of the valves are shown.  
         [0027]     In  FIG. 5 , the cylinder head covers are removed for clarity. Cylinder head  60  has two overhead camshafts  72  and  75 . Cylinder head  63  has two overhead camshafts  90  and  93 . Cylinder blocks  13  and  16  are mounted to the crankcase  22  at mounting ends  46 . The engine  10  is air cooled by means of fins  50 . An oil pump assembly  96  and oil pan  99  are installed in the crankcase  22  as known to those of ordinary skill in the art and therefore will not be described in detail herein. The lubrication system may comprise a high pressure feed, dry sump oiling system.  
         [0028]     Turning to  FIGS. 6-7 , the engine linkage is shown with the cylinder blocks, heads and covers removed for clarity. As shown a gear wheel  101  engaged with end portion  28  of the crankshaft  19  engages with a gear wheel  104 . Timing chains  107  and  110  are connected to drive sprockets  108 ,  109  by the gearshaft of gear wheel  104 . Driven sprockets  113  and  116  rotate gear wheels (not shown) that engage with gear wheels  119 ,  12 ,  125 , and  128  attached to camshafts  72 ,  75 ,  90 , and  93 . Rotation of the cam shafts causes the cams to rotate to open valves  69  at the intake and exhaust ports of the combustion chamber. The valves  69  include shim and bucket type lifters. And the camshafts may be provided with manual adjust cam chains.  
         [0029]     In  FIG. 8 , the cylinder bank angle  47  is shown. Also, the mounting holes  150  for mounting the transmission to the crankshaft  19  and crankcase  22  are shown.  
         [0030]     Turning to  FIG. 9 , the cylinder blocks  13  and  16  are preferably offset from a centerline  180  corresponding to the OEM cylinder centerline location. The cylinder block  13  has a centerline  181  that is offset from centerline  180  by a distance  183 . In the example, the distance  183  is 0.6 in. The cylinder block  16  has a centerline  182  that is offset from centerline  180  by a distance  186 . In the example, the distance is 0.6 in.  
         [0031]     Referring to  FIGS. 10-11 , the mounting arrangement for mounting the primary drive to the crankcase  22  and crankshaft  19  and for mounting the engine  10  to the frame is shown. The mounting locations are shown in relation to a reference point  300  located at the center of the crankshaft in the x and y directions and located at the primary drive mounting surface  209  in the z-direction.  
         [0032]     The axes are labeled  212 ,  215 , and  218 , respectively. The z-axis  218  is normal to the page in the orientation shown in  FIG. 10 . The front engine pad  200  has a pair of mounting holes  203  and  206 . As measured in inches from the reference point  300  (0, 0, 0) hole  203  is located at (−5½, −⅝, −1 13/16) and hole  206  is located at (−5½, −⅝, −5 1/16).  
         [0033]     The rear engine pad  230  has a pair of mounting holes  233  and  236 . Hole  233  is located at (5 3/16, 1, −1 13/16) and hole  236  is located at (5 3/16, 1, −5 1/16).  
         [0034]     The drive mounting surface  209  is provided with a plurality of mounting holes  350 ,  353 ,  356 , and  359 . As measured in inches from the reference point, hole  350  is located at (−3 1/16, 2 9/16, 0). Hole  353  is located at (−2 31/32, −2 11/16, 0). Hole  356  is located at (3 7/16, 2 1/16, 0). Hole  359  is located at (3½, −1 15/16, 0).  
         [0035]     In  FIG. 12 , a motorcycle frame  400  is shown. The frame  400  has an engine mount  403  for receiving the front engine pad  200  and has an engine mount  406  for receiving the rear engine pad  230 . The holes  203  and  206  align with openings  409  and  412  on the frame  400 .  
         [0036]     Holes  233  and  236  align with openings  415  and  418  in the engine mount  406 . As will be evident to those of ordinary skill in the art, the front and rear engine pads  200  and  230  may be used to attach the crankcase  22  to the motorcycle frame  400  by suitable fasteners.  
         [0037]     The frame  400  is an example of a frame that is suitable for use with the present invention. As will be evident to those of ordinary skill in the art, the engine  10  of the present invention can be used with any OEM or aftermarket frame having the EVO crankcase mounts and having sufficient clearance within the frame rails.  
         [0038]     Obviously, various minor changes and modifications of the present invention are possible in the light of the above teaching. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described.