Abstract:
A valve plate cover/lead frame unit of a lifter oil manifold assembly used in cylinder deactivation systems to direct engine oil to valve lifters including a body including a pattern of passages that in cooperation with a pattern of passages included in the valve plate form oil galleries for distributing the engine oil, an electrical connector and an electrical lead frame terminating the electrical connector integrated into the body, and a plurality of connector terminals incorporated into the body, wherein the electrical lead frame electrically connects each of the connector terminals with the electrical connector.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to internal combustion engines; more particularly, to devices for controlling systems in an internal combustion engine; and most particularly, to a valve plate cover with integrated lead frame of a lifter manifold assembly for variable activation and deactivation of valves in an internal combustion engine. 
       BACKGROUND OF THE INVENTION 
       [0002]    In conventional prior art four-stroke internal combustion engines, the mutual angular relationships of the crankshaft and the opening and closing of the combustion valves are mechanically fixed; that is, the valves are opened and closed fully and identically with every two revolutions of the crankshaft by a camshaft rotationally driven by the crankshaft with an axis of rotation parallel to the axis of rotation of the crankshaft. In engine operation, a fuel/air mixture is drawn into each cylinder in a predetermined sequence, the mixture is ignited by the sparking plug, and the burned residue is discharged. 
         [0003]    It is known that for much of the operating life of a multiple-cylinder engine, the load can be met by a functionally smaller engine having fewer firing cylinders, and that at times of low demand, fuel efficiency can be improved if one or more cylinders of a larger engine are withdrawn from firing service. It is known in the art to accomplish this by de-activating the valve trains leading to pre-selected cylinders (for example, one bank of intake and exhaust valves in a V-style engine) in any of various ways, such as by providing deactivating hydraulic valve lifters (DHVLs), deactivating roller finger followers (DRFFs), or deactivating hydraulic lash adjusters (DHLAs) which may be switched on and off electrically or hydraulically. (As used hereinafter, SVDD should be taken to mean generically any switchable valve deactivating device.) 
         [0004]    It is known in the prior art to controllably distribute oil to SVDDs to operate the SVDDs via a hydraulic manifold mounted to the top of the engine block and connected to an oil riser in the engine block. Such a manifold is known in the art as a Lifter Oil Manifold Assembly (LOMA). A typical LOMA is disclosed in U.S. Pat. No. 6,817,325, issued Nov. 16, 2004, which is incorporated herein by reference. 
         [0005]    Current technology in the automotive industry utilizes separately mounted Oil Control Valves (OCVs) in a manifold device. In the assembly of this device, all OCVs are linked and wired, to a single connector via a rigid wiring harness typically called a lead frame. Such a lead frame may be an overmolded set of wires forming a rigid harness. Rivets are typically used to attach the OCV terminals to the lead frame terminals. In other cases the OCV terminals may be welded to the lead frame terminals. In the prior art, the lead frame is a separate component in the LOMA and requires separate components and processes for attachment to a valve plate cover, which is undesirable from an economical point of view. 
         [0006]    What is needed in the art is a LOMA that includes a decreased number of components, enables a simplified assembly process, and provides a positive connection from the OCVs to the electrical circuit. 
         [0007]    It is a principal object of the present invention to provide a valve plate cover with an integral lead frame and an integral electrical connector and, therefore, an improved LOMA for controlling the hydraulic locking and unlocking of hydraulically-switched deactivating devices in an internal combustion engine. 
         [0008]    It is a further object of the invention to simplify the assembly and to reduce assembly costs of an internal combustion engine having variable valve activation via a plurality of SVDDs. 
       SUMMARY OF THE INVENTION 
       [0009]    Briefly described, an improved LOMA in accordance with the invention for managing pressurized oil delivered to the SVDDs includes a lead frame and an electrical connector integrated into a composite valve plate cover that is used to seal the valve plate (manifold) oil galleries thereby eliminating the lead frame and its attachment components as separate components of a typical prior art LOMA. To form the valve plate cover/lead frame unit, the wiring that connects all of the OCVs with an electrical connector is overmolded into the composite valve plate cover as is the electrical connector. The OCVs, which are plugged directly into sockets included in the valve plates, include terminals that intersect with M-slots or a similar type of electrical connections integral to the valve plate cover/lead frame unit in accordance with the invention. When the valve plate cover/lead frame unit is attached to the valve plate, as for example, by welding, the terminals of the OCVs are positively held in their mating interface integrated into the cover/lead frame unit. 
         [0010]    By forming the valve plate cover/ lead frame unit in accordance with the invention, the number of components in a LOMA is decreased and the assembly of a LOMA is simplified compared to a prior art LOMA. Furthermore, a positive electrical connection from the OCVs to the electrical circuit is enabled. 
         [0011]    An added advantage of overmolding the wires of the lead frame integral with the valve plate cover is that the lead frame wires now provide a “torcherous path” type seal and a secondary sealant operation as needed in the assembly of a prior art LOMA to prevent oil wicking along the wires to the connector terminals and from there to the atmosphere is not necessary anymore. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: 
           [0013]      FIG. 1  is an isometric view of a valve plate assembly in accordance with the present invention; 
           [0014]      FIG. 2  is an isometric view of a valve plate cover/lead frame unit in accordance with the invention; 
           [0015]      FIG. 3  is a plan view of the valve plate cover/lead frame unit shown in  FIG. 2 , showing the paths, in dashed lines, forming oil supply galleries; and 
           [0016]      FIG. 4  is a horizontal cross-sectional view of the valve plate cover/lead frame unit shown in  FIGS. 2 and 3 , showing integrated lead frame wires. 
       
    
    
       [0017]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one presently preferred embodiment of the invention, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
       DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    Referring to  FIGS. 1 through 3 , a valve plate assembly  10  in accordance with the present invention includes a valve plate  20  and a valve plate cover/lead frame unit  30  (shown in detail in  FIG. 2 ). Valve plate assembly  10  is part of a LOMA for controlling the hydraulic locking and unlocking of SVDDs, such for example deactivatable valve lifters, in an internal combustion engine. 
         [0019]    A first pattern of passages  22  is formed in valve plate  20 . Similarly, a second pattern of passages  32  is formed in an underside  42  of a body  31  of valve plate cover/lead frame unit  30 . Passages  32  may be expressed as a corresponding pattern of raised sections  34  on the upper surface  44  of body  31  (also shown in  FIG. 2 ). The patterns of passage  22  and  32  in valve plate  20  and cover/lead frame unit  30  cooperate to define and form the oil galleries  28  of a complex three dimensional network for selectively distributing pressurized oil from an engine oil riser (not shown). An oil inlet port  54  integrated into body  31  of cover/lead frame unit  30  is used to supply oil to oil galleries  28 . 
         [0020]    Valve plate  20  and body  31  of cover/lead frame unit  30  preferably are formed of a thermoplastic polymer having a relatively high melting temperature, for example, a glass-filled polyphthalamide (PPA) or a glass-filled nylon. Valve plate  20  and cover/lead frame unit  30  may be joined along mating surfaces preferably by fusion, such as, for example, by vibration welding or laser welding. During the welding operation, the mating surfaces liquefy, compress, and fuse in a fusion zone, forming a mechanical and hermetic seal  36  defining the oil galleries  28  in valve plate assembly  10  (as shown in  FIGS. 1 and 3 ). 
         [0021]    Valve plate  20  includes a plurality of sockets  24  for receiving a plurality of solenoid-actuated OCVs  26  for controlling oil flow from passages  22  and  32  to individual 
         [0022]    SVDDs (not shown) in a deactivation-equipped engine. Solenoid-activated OCVs  26  may be retained in their respective sockets  24 , for example, by a separate retainer or by having individual flanges that can be thermally welded to valve plate  20 . Typically, each OCV  26  controls the activation and deactivation of all SVDDs (intake and exhaust) for a given cylinder of a multi-cylinder engine via outlet ports (not visible); thus, in the typical example, four control valves  26  are required to deactivate valves for four cylinders of a bank of an eight-cylinder V-style engine. However, it is possible that a single OCV could control the operation of the SVDDs of more than one cylinder. 
         [0023]    As shown in  FIGS. 1 through 3 , body  31  of valve plate cover/lead frame unit  30  further includes a plurality of clearance holes  38  and at least one mounting boss  39  for mounting valve plate assembly  10  to an engine, for example, within a valley of a V-style engine. Valve plate cover/lead frame unit  30  still further includes a plurality of connector terminals  46 , such as M-slots or similar type of electrical connectors, integrated into body  31 , for example by overmolding, and an electrical connector  48 . Electrical connector  48  is preferably integrated into cover/lead frame unit  30  by overmolding and may be positioned at various locations on the upper surface  44  of cover/lead frame unit  30 . Exemplary positions of connector  48  are shown in  FIG. 1  and in  FIGS. 2-4 . 
         [0024]    Referring now to  FIG. 4 , an electrical lead frame  50  for supplying electrical signals from an Engine Control Module (not shown) to the solenoids of OCVs  26  is integrated into valve plate cover/lead frame unit  30  terminating electrical connector  48 . Lead frame wires  52  electrically connect each connector terminal  46 , such as the M-slots shown, with electrical connector  48 . As can be seen in  FIG. 4 , lead frame wires  52  do not cross seal  36  (shown in  FIGS. 1 and 3 ) defining the oil galleries  28 . This allows lead frame wires  52  to be overmolded during the manufacture of cover/lead frame unit  30 . By overmolding lead frame wires  52 , a “torcherous path” type seal that prevents oil wicking along the wires  52  to connector terminals  46  and from there to the atmosphere is instantly formed around wires  52 . Secondary sealing operations needed in the prior art for this purpose have been eliminated. 
         [0025]    For each OCV  26  received by valve plate  20 , one M-slot  46  or similar type of connector is integrated into cover/lead frame unit  30 . When an OCV  26  is plugged into a socket  24  of valve plate  20 , the terminal of the OCV  26  directly intersects with one of the M-slots  46 . When cover/lead frame unit  30  is welded in place, the terminals of the OCVs  26  are held positively by the mating interface of M-slots  46 . 
         [0026]    By designing cover lead/frame unit  30  as a single integral part with integrated lead frame wires  52 , an integrated electrical connector  48 , and integrated M-slots  46 , the number of components that form valve plate assembly  10  is decreased, assembly operations of valve plate assembly  10  is simplified, and a positive connection is provided from the OCVs  26  to the electrical circuit. 
         [0027]    A simplified process for assembling the valve plate assembly  10  includes the insertion of compression limiters into clearance holes  38 . In a following step, cover/lead frame unit  30  is welded to valve plate  20 . After press-in-place gaskets (not shown) are pressed into valve plate  20  in various locations, a first leak check may be performed. In a following step, the OCVs  26  are inserted into sockets  24  integral with valve plate  20 . After a second leak check, the OCVs  26  are welded in place. A cap may be attached to cover oil inlet port  54  for protection of oil galleries  28  prior to assembly of valve plate assembly  20  into a LOMA. 
         [0028]    In addition to a reduction in components and assembly process steps, the proposed design of valve plate assembly  10 , and especially of cover/lead frame unit  30 , offers substantial cost reduction over a prior art LOMA design. 
         [0029]    While the invention has been described in reference to a V-type engine, it is understood that the invention is applicable to other type engines. 
         [0030]    While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims.