Abstract:
A two-piece valve cover for use on an engine having an engine cylinder head and a plurality of valve rocker arms. The two-piece valve cover includes a base housing for sealing with the cylinder head and a top cover. The top cover includes a sealing flange adapted to receive a sealing gasket member. The second sealing gasket member is retained on the top cover for forming a seal between said top cover and said base housing.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    This invention is related to the field of internal combustion engines having valve train assemblies covered by valve covers. More specifically, this invention relates to two-piece valve covers. 
         [0003]    2. Discussion 
         [0004]    Valve train assemblies include, amongst other items, valve rocker arms and push rods lubricated with engine oil. In order to maintain the effective and efficient working of such valve train assemblies, such assemblies must remain lubricated and must be protected from debris in the engine compartment. As such, valve train assemblies are usually provided with a cover, more commonly referred to as a valve cover, attached to the engine in order to prevent the loss of engine oil and to protect such assemblies from debris. 
         [0005]    The valve covers are attached to the engine with the use of a gasket and various fasteners. The gasket provides for an effective sealing arrangement between the valve cover and the engine head. Some examples of such gaskets are known to be O-ring type gaskets having a circular cross section, flat type gaskets having a rectangular-like cross section, and custom molded gaskets having a variety of cross-sections. In some cases, the gasket is placed on a sealing surface of an engine head with the use of a sealing compound in order to assist in retaining the gasket on the engine head while locating and attaching the valve cover to the engine head and in some cases, mechanical fasteners can accomplish the same purpose. The mechanical fasteners are usually threaded bolts or stud and nut combinations. 
         [0006]    To permit the repair of valve train components, the valve covers must be removed in order to provide access to such components. After removing the fasteners retaining the valve cover to the engine head, the valve cover is removed from the engine head to thereby expose the valve train components for inspection, adjustment, and repair. Usually when removing the valve cover, the engine oil found in the cylinder head area can spill out into other areas of the engine compartment and the adjacent floor surface causing a considerable mess. In the case of racing activities involving an engine, the valve train assemblies play an important role in such activities and, as such, the immediate need to remove the valve covers quickly, easily, and neatly becomes important. In such cases, mechanics need to have rapid access to the valve train in order to inspect, adjust, or repair certain components of the valve train. 
         [0007]    Prior art valve covers include both one and two-piece valve covers. Such prior art valve covers are typically made by stamping steel or by casting various materials. Usually, the prior art valve covers are heavy or utilize a significant and costly amount of material since a substantial wall and mounting flange thickness is needed to provide for a distortion-resistant and leak-resistant flange to seal the engine reliably or, in the case of a two-piece valve cover, to seal both pieces of the two-piece valve covers together reliably. These heavy and substantial prior art valve covers are time consuming and difficult to assemble to, and remove from, the engine. In addition, prior art valve covers utilize old conventional sealing arrangements which add cost and complexity to the valve covers. Such old conventional sealing arrangements for one and two-piece valve covers are known to include features on the mounting flange (the portion of the cover configured to seal with the engine head) for retaining a gasket to such flange. Such covers having retaining features on the mounting flange require a larger dimension and/or greater wall thickness thereby increasing weight and material consumption. Also, another deficiency of the prior art is the failure to provide for the retention of engine oil upon the removal of the prior art valve covers from the engine head, such failure occurring whether the engine is turned off or operating. 
       SUMMARY OF THE INVENTION 
       [0008]    In view of the above, the present invention is directed to a two-piece valve cover providing for the easy and rapid removal and replacement of a top portion of the two-piece valve cover. 
         [0009]    Another object of the invention is to provide for a lightweight two-piece valve cover. 
         [0010]    Another object of the invention is to minimize oil spillage whether the engine is turned off or operating; 
         [0011]    Another object of the invention is to provide for a two-piece valve cover which minimizes the amount of material used in the manufacture thereof. 
         [0012]    Another object of the invention is to provide for an effective seal between the two portions of a two-piece valve cover. 
         [0013]    In accordance with a preferred embodiment of the present invention, a two-piece valve cover for use on an engine having an engine cylinder head and a plurality of valve rocker arms is provided. The two-piece valve cover includes a base member for sealing a base housing to the cylinder head through the use of a first sealing gasket member. The base housing includes an inner region surrounding the plurality of valve rocker arms and a flange on the base housing extending outwardly from the inner region and around at least a portion of the base housing. The two-piece valve cover further includes a top cover for sealing engagement with the base housing through the use of a second sealing gasket member. The top cover includes a sealing flange extending around at least a portion of the top cover and a lip portion extending toward the base housing for locating the top cover on the base housing. The second sealing gasket member is retained on the top cover for forming a seal between the top cover and the base housing. 
         [0014]    Further scope of applicability of the present invention will become apparent from the following detailed description, claims, and drawings. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The present invention will become more fully understood from the detailed description given here below, the appended claims, and the accompanying drawings in which: 
           [0016]      FIG. 1  is a perspective view of a preferred embodiment of the invention; 
           [0017]      FIG. 2  is a side view of a preferred embodiment of the invention; 
           [0018]      FIG. 3  is a side view of a preferred embodiment of the invention; 
           [0019]      FIG. 4  is a plan view of a preferred embodiment of the invention; 
           [0020]      FIG. 5  is an end view of a preferred embodiment of the invention; 
           [0021]      FIG. 6  is an end view of a preferred embodiment of the invention; 
           [0022]      FIG. 7  is a cross-section end view taken along line A-A in  FIG. 4 ; 
           [0023]      FIG. 8  is a perspective view of a preferred embodiment of the subject invention in a disassembled state; and 
           [0024]      FIG. 9  is an end view of an engine showing a preferred embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0025]    In accordance with the illustrated embodiment of the present invention,  FIGS. 1-8  show a preferred embodiment of the two-piece valve cover. As shown in  FIGS. 1-3 , the two-piece valve cover generally shown at  10  includes a base housing  12  and a top cover  14 . The base housing  12  is adapted for sealingly engaging a cylinder head of an engine through the use of a first sealing gasket member (not shown). It should be appreciated that the first sealing gasket may be made of several types of known materials and configurations including, for example, an O-ring type gasket. The base housing  12  further includes a base housing flange  18  extending around the base housing  12  and outwardly from an inner region  16 , as shown in  FIGS. 7 and 8 . The inner region  16  is configured for surrounding a valve train assembly (not shown) of an engine. In this embodiment, the base housing flange  18  extends continuously around the base housing  12 ; however, it should be appreciated that other embodiments may include the base housing flange  18  extending around portions of the base housing  12 . 
         [0026]      FIG. 4  is a plan view of the present invention showing a sealing flange  26  extending around the top cover  14  and adapted for mating with the base housing flange  18  of the base housing  12  during assembly, as shown in  FIGS. 1 and 2 . As shown in  FIGS. 5-8 , the top cover  14  is adapted for sealingly engaging the base housing  12  with the use of a second sealing gasket member  20 . The second sealing gasket member  20  is adapted to be retained on the sealing flange  26  of the top cover  14 . Compared to prior art valve covers, the top cover  14  includes a very thin wall thickness. A wall thickness of approximately 2.8 mm to 3.0 mm for the top cover  14  has been found to provide a sufficient structural stiffness while reducing the overall weight of the top cover  14 . The top cover  14  includes a lip portion  22  extending in a direction towards the base housing  12 . In this embodiment, the lip portion  22  is configured to abut an inner surface  24  of the base housing  12 . As more fully described below, the lip portion  22  is useful during the assembly of the top cover  14  to the base housing  12  in that the lip portion  22  interfaces with the inner surface  24  of the base housing  12  to position the top cover  14  on the base housing  12 . 
         [0027]    The base housing  12 , as shown in  FIGS. 5 and 6 , includes a first  30  and second  32  wall portion. The first wall portion  30  includes a wall height C, extending in a direction away from the engine (not shown), which is less than a wall height D of the second wall portion  32 . In this embodiment, as more fully described below, the wall height C and the second wall height D are configured such that the base housing flange  18  is substantially parallel to a horizontal axis of the engine  42  as shown along line II in  FIG. 9 . It has been found that by providing the base housing  12  with varying wall heights, such that the base housing flange  18  is substantially parallel to a horizontal axis of the engine  42 , any oil that may be in the valve rocker arm area region while the engine is running is retained in the inner region  16  of the base housing  12  upon removal of the top cover  14  from the base housing  12 . 
         [0028]      FIG. 8  shows the two-piece valve cover  10  in its unassembled state and more specifically the top cover  14  shown upside down. The top cover  14  includes retention features  28  adapted to retain the second sealing gasket member  20  to the top cover  14 . As shown in  FIG. 8 , in its unassembled state, the two-piece valve cover  10  includes the second sealing gasket member  20  retained on the sealing flange  26  of the top cover  14 . In this embodiment, the retention features  28  are shaped as notches in the lip portion  22 ; however, it should be appreciated that other various retention features may be used. The second sealing gasket member  20  is substantially flat in  FIG. 8 ; however, it should be appreciated that other configurations and cross-sections of a gasket including, for example, an O-type ring type sealing gasket may be used. Also, the second sealing gasket member  20  includes tabs  38  for use in connection with the retention feature  28 . Since the top cover  14  includes the lip portion  22  having retention features  28  for retaining the second sealing gasket member  20  thereto, it has been found that the material thickness of the top cover  14  and the base housing  12  can be minimized. In minimizing the material thickness of the top cover  14 , the overall weight and material cost of the top cover  14  are also reduced. 
         [0029]      FIG. 8  further shows apertures  34  formed on the inner region  16  of the base housing  12 . The top cover  14 , as shown in  FIG. 8 , includes bores  36  extending through the top cover  14  and configured in alignment with the apertures  34  of the base housing  12  for receiving a fastener (not shown) therein for retaining the first cover  14  to the base housing  12 . Base housing  12  includes bores  40  for use in connection with a fastener (not shown) to attach the base housing  12  to the engine head. It should be appreciated that the top cover  14  may be fastened to the base housing  12  through the use of many types of fasteners, including, for example, a bolt. 
         [0030]    The top cover  14  and the base housing  12  can be made by casting materials including aluminum, magnesium, plastic, and steel. It should be appreciated that, although the present embodiment of the subject invention is shown as a cast part, the base housing  12  may also be made from stamping steel. 
         [0031]    During assembly of the two-piece valve cover  10  to the engine, the base housing  12  is attached to the head of the engine having the wall portions  30 ,  32  selected and positioned to be substantially parallel to a horizontal axis of the engine, as shown along line II in  FIG. 9 . After sealingly attaching the base housing  12  to the head of the engine, with use of the a first sealing gasket (not shown) and fastener extending through bores  40 , the top cover  14  is fitted with the second sealing gasket member  20  such that the gasket  20  is retained to the top cover  14  as shown in  FIG. 8 . The top cover  14  is then positioned and aligned with the base housing  12  by inserting the lip portion  22  inside the base housing  12  and abutting the inner surface  24  as shown in  FIG. 7 . Fasteners are inserted into bores  36  on the top cover  14  and extend into apertures  34  of the base housing  12 . In this embodiment, the fasteners and the apertures  34  are configured with threads. In the case of racing activities involving engines, the top cover  14  can be easily removed from the base housing  12  by removing the fasteners. When the top cover  14  is removed, the second sealing gasket member  20  remains retained to the top cover  14  and, since the base housing  12  is configured with different wall heights C and D, much of the lubricating engine oil is retained in the inner region  16  of the base housing  12 , even when the engine is operating. 
         [0032]    The foregoing discussion discloses and describes an exemplary embodiment of the present invention. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims that various changes, modifications and variations can be made therein without departing from the true spirit and fair scope of the invention as defined by the following claims.