Abstract:
A windage tray apparatus is provided and is configured to be mountable within a crankcase at least partially defined by an engine block of an internal combustion engine. The crankcase has a first bay and a non-adjacent second bay. The internal combustion engine has a crankshaft rotatably supported within the crankcase. The windage tray includes a tray member and a passage at least partially defined by said tray member and in communication with the first bay and the non-adjacent second bay. The passage is operable to allow gas transfer between the first bay and the non-adjacent second bay to reduce the motoring friction of the internal combustion engine. An internal combustion engine incorporating the disclosed windage tray apparatus is also provided.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a windage tray for an internal combustion engine. 
       BACKGROUND OF THE INVENTION 
       [0002]    An oil pan is typically disposed beneath an engine block and crankshaft of an internal combustion engine, and is configured to receive oil that drains or is otherwise exhausted from the engine block, valvetrain, crankshaft, and/or main bearings that support the crankshaft. The oil collects in a sump of the oil pan and is then pumped from a sump pick-up location into a lubrication system associated with the internal combustion engine. 
         [0003]    The rotation of the crankshaft and the reciprocal motion of pistons will cause gases to move within the crankcase, the volume within which the crankshaft is housed, causing turbulence. These turbulent gases may be referred to as “windage.” During operation of the internal combustion engine, some oil that would otherwise drain into the oil pan may instead become entrained in the gases. Accordingly, some vehicle engines include an oil deflector, also referred to as a “windage tray” to separate the crankshaft from the oil pan in order to reduce or eliminate the effects of crankshaft rotation on oil stored or collected in the oil pan. The oil deflector operates to remove oil from the gasses and prevent the entrainment of oil by the gases, which allows the oil to drain back to the sump and be recirculated through the engine&#39;s lubrication system. Additionally, the operating efficiency of the internal combustion engine may be reduced due to the inefficient transfer of gases within the crankcase as a result of the pumping action associated with the reciprocal motion of pistons within the internal combustion engine. This gas transfer characteristic is referred to as “bay-to-bay breathing”. The transfer of gases between volumes or bays of the crankcase is often impeded by structural obstructions such as bulkheads, main bearing caps, etc. 
       SUMMARY OF THE INVENTION 
       [0004]    A windage tray apparatus is provided and is configured to be mountable within a crankcase at least partially defined by an engine block of an internal combustion engine. The crankcase has a first bay and a non-adjacent second bay, i.e. at least a third bay disposed between the first and the second bay. The internal combustion engine has a crankshaft rotatably supported within the crankcase. The windage tray includes a tray member and a passage at least partially defined by said tray member and in communication with the first bay and the non-adjacent second bay. The passage is operable to substantially allow gas transfer between the first bay and the non-adjacent second bay to reduce the motoring friction of the internal combustion engine. An internal combustion engine incorporating the claimed windage tray is also disclosed. 
         [0005]    The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a exploded perspective view of the underside of an internal combustion engine having a windage tray mountable within a crankcase having a first second, third, and fourth bay; 
           [0007]      FIG. 2  is a graph illustrating displaced volume versus crank angle for each of the first, second, third, and fourth bay of  FIG. 1 ; 
           [0008]      FIG. 3  is a perspective view of the underside of the windage tray of  FIG. 1 ; 
           [0009]      FIG. 4  is a perspective view of the topside of the windage tray of  FIG. 1 ; and 
           [0010]      FIG. 5  is a cross sectional view of a portion of the windage tray of  FIGS. 2 and 3  illustrating a method of mounting the windage tray. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0011]    Referring to the drawings wherein like reference numbers correspond to like or similar components throughout the several views, there is shown in  FIG. 1  a portion of an internal combustion engine, generally indicated at  10 . The internal combustion engine  10  of  FIG. 1  is an eight cylinder, V-type engine. The internal combustion engine  10  includes an engine block  12  preferably formed from cast metal such as, for example, aluminum, iron, magnesium, etc. The engine block  12  has a mounting surface  13  adapted to mount an oil pan, not shown, to the internal combustion engine  10 . The engine block  12  rotatably supports a crankshaft  14 . The crankshaft  14  is retained with respect to the engine block  12  by a plurality of main bearing caps  16  and rotates about an axis of rotation, indicated at A. The main bearing caps  16  are mounted to the engine block  12  by fasteners  17 . The crankshaft  14  operates to convert the reciprocal motion of pistons, not shown, into rotational motion. 
         [0012]    The engine block  12  at least partially defines a crankcase  18 . The crankcase  18  includes a first bay  20 , corresponding to a first and second cylinder (both not shown), a second bay  22 , corresponding to a third and fourth cylinder (both not shown), a third bay  24 , corresponding to a fifth and sixth cylinder (both not shown), and a fourth bay  26 , corresponding to a seventh and eighth cylinder (both not shown). The engine block  12  is characterized as having a “deep skirt” design such that skirt portions  28  and  30  depend or extend from the engine block  12  and cooperate with the main bearing caps  16  to partially define the first, second, third, and fourth bay  20 ,  22 ,  24 , and  26 . The first, second, third, and fourth bay  20 ,  22 ,  24 , and  26  each vary in volume with the operation of the internal combustion engine  10  and contain an amount of gas therein. 
         [0013]    A windage tray  32  is configured to mount within the crankcase  18  of the internal combustion engine  10 . The windage tray  32  is preferably positioned between the crankshaft  14  and the oil pan of the internal combustion engine  10  and is operable to reduce oil entrainment of the windage or turbulent gases within the crankcase  18  during operation of the internal combustion engine  10 . The windage tray  32  is preferably formed from a stamped metal, such as steel or aluminum. A plurality of nuts  34 , one of which is shown in  FIG. 1 , cooperate with the fasteners  17  to mount the windage tray  32  within the crankcase  18 . The method of mounting the windage tray  32  via the fasteners  17  and nuts  34  will be discussed in greater detail herein below with reference to  FIG. 5 . The various aspects of the windage tray  32  will be discussed in greater detail hereinbelow with reference to  FIGS. 3 and 4 . 
         [0014]    An exemplary firing order, i.e. the order in which a fuel and air mixture contained within the cylinders is ignited to effect or initiate the expansion stroke of the respective piston, for the internal combustion engine  10  is 1-8-4-3-6-5-7-2 (following the cylinder numbering convention wherein one bank of the eight cylinder engine includes the odd numbered cylinders in ascending order, while the opposite bank includes the even numbered cylinders in ascending order). As such, the relative displaced volume within the first, second, third, and fourth bays  20 ,  22 ,  24 , and  26  as a result of the reciprocal motion of the pistons may be mapped with respect to the rotational angle of the crankshaft  14  as shown in graph  36  of  FIG. 2 . 
         [0015]    Referring to  FIG. 2 , the graph  36  illustrates the displaced volumes of the first, second, third, and fourth bays  20 ,  22 ,  24 , and  26  with respect to crank angle for an exemplary eight cylinder, V-type internal combustion engine having  4 . 7  liters of displacement. Curve  38  illustrates the volume displaced of the first bay  20  during operation of the internal combustion engine  10 . Positive values for displaced volumes indicate the volume of the first bay  20  is greater than the equilibrium value, i.e. zero displaced volume. Alternatively, negative values for displaced volumes indicate the volume of the first bay  20  is less than the equilibrium value. A similar convention will apply to curve  40 , corresponding to the second bay  22 , curve  42 , corresponding to the third bay  24 , and curve  43 , corresponding to the fourth bay  26 . As illustrated in  FIG. 2  by curves  38  and  43  the respective volumes of the first and fourth bay  20  and  26  are oppositely and alternately displaced. Similarly, curves  40  and  42  illustrate that the respective volumes of the second and third bay  22  and  24  are oppositely and alternately displaced. Since the second and third bays  22  and  24  are substantially adjacent to each other, displaced gases may alternately pass from the second bay  22  to the third bay  24  and from the third bay  24  to the second bay  22  to balance the flow of gases and reduce any pressure rise within one of the second bay  22  and the third bay  24 , thereby reducing motoring frictional losses within the internal combustion engine  10 . However, the first bay  20  and the fourth bay  26  are substantially non adjacent to one another, i.e. are separated by the second and third bays  22  and  24 , as illustrated in  FIG. 1 ; therefore, the path that the gases must traverse to balance the flow of gases and reduce any pressure rise within one of the first and fourth bays  20  and  26  may be tortuous or circuitous resulting in an increase in motoring frictional losses and a decrease in the operating efficiency of the internal combustion engine  10 . This transfer of gas between bays during operation of the internal combustion engine  10  is termed bay-to-bay breathing. 
         [0016]    Referring now to  FIG. 3  and with continued reference to  FIG. 1 , there is shown the windage tray  32  of  FIG. 1  further illustrating the aspects of the preferred embodiment. The windage tray  32  includes a tray member  44  at least partially defining a passage  46 , shown in  FIG. 4 . The passage  46  extends substantially the length of the tray member  44  and is in communication with the first and fourth bays  20  and  26 . The passage  46  is operable to promote gas exchange of transfer between the first and fourth bays  20  and  26  as a result of the volumetric changes of the first and fourth bays  20  and  26  during operation of the internal combustion engine  10  (see  FIG. 2 ). The passage  46  is preferably formed from a channel member  48  formed from sheet metal and attached or mounted to the tray member  44 . The channel member  48  may be formed from steel, stainless steel, aluminum, etc. and may be affixed to the tray member  44  using known fastening means, such as welding, bonding, mechanical fastening etc. 
         [0017]    Shields  50  and  52 , shown in  FIG. 4 , depend or extend from the tray member  44  and are configured to engage a respective skirt portion  28  and  30  of the engine block  12 . The shields  50  and  52  are operable to direct oil draining from the cylinder heads, not shown, and the engine block  12  away from the rotating crankshaft  14  thereby reducing or preventing oil from being entrained by the gases within the crankcase  18 . The shields  50  and  52  may be formed integrally with the tray member  44  or may be formed separately and attached using known fastening techniques. 
         [0018]    Referring to  FIG. 4  and with continued reference to  FIGS. 1 and 3 , there is shown a perspective view of the topside, i.e. the side adjacent to the crankshaft  14 , of the windage tray  32  of  FIG. 3 . Windows or orifices  54  are defined by the tray member  44  and are operable to provide communication between the first and fourth bays  20  and  26  and the passage  46 . The tray member  44  defines a plurality of louvers or slots  56  operable to promote the drain back of oil being thrown from the rotating crankshaft  14 . The slots  56  preferably extend longitudinally along the tray member  44  generally parallel to the axis of rotation A of the crankshaft  14 . A scraper  58  is mounted to the tray member  44  such that the scraper  58  is positioned substantially adjacent to the crankshaft  14  when the windage tray  32  is mounted to the internal combustion engine  1 O. The scraper  58  has a contoured profile  60  to approximate the rotational profile of the crankshaft  14 . The scraper  58  is operable to strip or remove oil from the rotating crankshaft  14  during operation of the internal combustion engine  10 , thereby reducing the likelihood of oil entrainment within the windage. 
         [0019]    A plurality of recesses  62  are defined by the tray member  44  and are operable to substantially enclose at least a portion of the fasteners  17  thereby allowing the windage tray  32  to fit closer to the crankshaft  14  when mounted to the internal combustion engine  10 . The method of mounting the windage tray  32  with respect to the internal combustion engine  10  will be discussed in greater detail hereinbelow with reference to  FIG. 5 . 
         [0020]    Referring now to  FIG. 5 , there is shown a sectional view of a portion of the internal combustion engine  10  of  FIG. 1  illustrating a fastening method consistent with the preferred embodiment. The fastener  17  includes a threaded stud  64  operable to threadingly engage the engine block  12 . A nut  66  threadingly engages the stud  64  and cooperates with a washer  68  to retain the main bearing cap  16  with respect to the engine block  12 . The recess  62  defined by the tray member  44  is configured to receive at least a portion of the nut  66  therein such that the tray member  44  is compactly mounted with respect to the crankshaft  14 , shown in  FIG. 1 . The nut  34  threadingly engages a threaded portion  72  of the stud  64  that extends from nut  66 . The nut  34  is operable to retain the tray member  44  with respect to the internal combustion engine  10 . The stud  64  and nut  66  may be formed integrally or separate, as shown in  FIG. 5  while remaining within the scope of that which is claimed. 
         [0021]    By reducing the flow restriction between the first bay  20  and the fourth bay  26  of the crankcase  18  via the passage  46 , the crankcase fluid pumping losses of the internal combustion engine  10  may be reduced, thereby improving the high speed power output of the internal combustion engine  10 . Additionally, the windage tray  32  is operable to reduce the oil entrainment within the gases thereby further reducing frictional losses within the internal combustion engine  10 . As a result of reduced frictional losses, the windage tray  32  may lower bulk oil temperatures at high engine speed and full load operating conditions. Furthermore, the windage tray  32  is effective in reducing the oil aeration thereby improving the effectiveness of the lubrication system of the internal combustion engine  10  at high engine speeds under part and full load operating conditions. 
         [0022]    The discussion hereinabove have focused mainly on the bay-to-bay breathing characteristics of an eight cylinder v-type internal combustion engine: however, those skilled in the art will recognize that the claimed windage tray may be incorporating within alternate engine architectures, such as six cylinder v-type and inline engines, while remaining within the scope of that which is claimed. While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.