Abstract:
A lifter oil manifold assembly for variable actuation of engine valves having first (top) and second (valve) plates having portions of oil control and oil exhaust passages formed therein. The assembly further includes a carrier member having an oil supply passage integrated thereby separating the oil supply path from the oil control and oil exhaust path. Further, the assembly includes towers for receiving and positioning the electro-magnetic oil control valves used to control oil flow in the assembly. The towers are molded separate from the carrier and are held in place by the valve plate or are molded integral with the carrier. In another aspect of the invention, oil control valve retention springs are molded integral with either the tower or the oil control valve. In a further aspect of the invention, a combined polymer restrictor/strainer in the oil circuit replaces a prior art metal die-cast restrictor.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/919,623, filed Mar. 23, 2007. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to internal combustion engines; more particularly, to devices for controlling systems in an internal combustion engine; and most particularly, to an improved lifter oil manifold assembly for controlling the flow of engine oil in the variable activation and deactivation of valve lifters in an internal combustion engine. In one embodiment, the mechanism for receiving the oil control valves (OCVs) in the lifter oil manifold assembly and the oil supply, control and exhaust passages are improved. In another embodiment, a simplified restrictor valve, including a filtering element integrated with a restrictor orifice is incorporated in the manifold assembly. 
       BACKGROUND OF THE INVENTION 
       [0003]    In conventional prior art four-stroke internal combustion engines, the mutual angular relationships of the crankshaft, camshaft, and valves are mechanically fixed; that is, the valves are opened and closed fully and identically with every two revolutions of the crankshaft, fuel/air mixture is drawn into each cylinder in a predetermined sequence, ignited by the sparking plug, and the burned residue discharged. This sequence occurs irrespective of the rotational speed of the engine or the load being placed on the engine at any given time. 
         [0004]    It is known that for much of the operating life of a multiple-cylinder engine, the load might be met by a functionally smaller engine having fewer firing cylinders, and that at low-demand times fuel efficiency could be improved if one or more cylinders of a larger engine could be withdrawn from firing service. It is known in the art to accomplish this by de-activating the valve train leading to pre-selected cylinders in any of various ways, such as by providing special valve lifters having internal locks which may be switched on and off either electrically or hydraulically. Such switching is conveniently performed via a hydraulic manifold that utilizes electric solenoid valves to selectively pass engine oil to the lifters upon command from an engine control module (ECM). Such a manifold is referred to in the art as a Lifter Oil Manifold Assembly (LOMA). 
         [0005]    Prior art LOMAs are made up of several components including a cast aluminum top plate with cast and/or machined oil passages for carrying engine oil under pressure to and from the oil control valves (OCVs), a cast and/or machined aluminum valve plate for receiving the OCVs and connecting the OCVs to the oil passages, a resilient carrier member for sealing between the top plate and valve plate, a lead frame for making electrical connections to the OCVs and, of course, the OCVs themselves. 
         [0006]    Thus, prior art LOMAs are typically complex assemblies that include a variety of parts that require individual manufacturing operations, cost, and cycle time. For example, the OCV seat is typically machined into the valve plate and the OCVs are retained in the valve plate with a snap ring. A tolerance gap between the OCV flange and the valve plate is resolved with a wave spring to retain each OCV in the seated position. This assembly works satisfactory however, requires secondary machining to the valve plate. Also, with the spring as a separate part there is a risk that an assembly is built without the spring in place, which could lead to a reciprocating movement of the OCV with the supply pressure. In such a case, the OCV would be susceptible to damage from vibration. 
         [0007]    Furthermore, the oil supply gallery is typically integral to the top plate. Consequently, the oil supply gallery is located in the same surface as the control gallery, while it is desirable for a more efficient functionality of the LOMA to position the control path and the supply path in different surfaces. 
         [0008]    In still another example, typical prior art LOMAs include four press-in-place metering valves that contain a small orifice in order to act as a flow limiter for engine oil passing through the LOMA. The metering valves are typically made out of zinc die-cast in a two-stage manufacturing process and contain no immediate contaminant protection that may, for example, screen out debris from the engine oil, which could damage or block the small orifice. 
         [0009]    What is needed in the art is an improved and simplified LOMA that involves fewer parts to be assembled, that involves parts that can be easily manufactured, and that can be easily integrated into a high volume manufacturing operation. 
         [0010]    It is a principal object of the present invention to provide an improved LOMA for controlling the hydraulic locking and unlocking of deactivatable valve lifters in an internal combustion engine, wherein the oil supply gallery is located in the gasket carrier, and wherein the OCV seats are formed separate from the cast aluminum valve plate by injection molding of a polymer. 
         [0011]    It is a further object of the invention to provide such a LOMA wherein a simplified orifice restrictor, coupled with a strainer for keeping unwanted debris away from the orifice restrictor, is used. 
         [0012]    It is a still further object of the invention to provide such an assembly comprising components, which may be easily fabricated, and preferably which are formed of a suitable thermoplastic polymer wherein after-cast machining of the components are kept to a minimum. 
       SUMMARY OF THE INVENTION 
       [0013]    Briefly described, a lifter oil manifold assembly for variable actuation of engine valves in accordance with the invention includes first (top) and second (valve) plates having portions of oil flow passages integrally formed therein. The plates are formed preferably of a die-cast metal such as aluminum. The assembly further comprises a carrier member also having portions of oil flow passages mating with the oil passages of the first and second plates. Further, the assembly includes towers for receiving and positioning the electro-magnetic oil control valves used to control oil flow in the assembly. The towers are formed of a suitable polymer and many of the critical features of the towers are as-molded. 
         [0014]    In one aspect of the invention, the oil supply passage is integral to the carrier. In another aspect of the invention, the towers are molded separate from the carrier and are held in place by the valve plate. In still another aspect of the invention, the towers are molded integral with the carrier. In yet other aspects of the invention, oil control valve retention springs are molded integral with either the tower or the oil control valve. In a further aspect of the invention, a combined polymer restrictor/strainer in the oil circuit of the lifter oil manifold assembly replaces a metal die-cast restrictor. The present hydraulic manifold results in an improved performance and in a savings in manufacturing cost over prior art manifolds. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    These and other features and advantages of the invention will be more fully understood and appreciated from the following description of certain exemplary embodiments of the invention taken together with the accompanying drawings, in which: 
           [0016]      FIG. 1  is a schematic drawing of a prior art hydraulic circuit controlling the activation/deactivation of valves of one cylinder (this circuit would be repeated for each cylinder having a deactivation feature); 
           [0017]      FIG. 2  is an isometric view of a prior art LOMA; 
           [0018]      FIG. 3  is a cross-sectioned view of a prior art LOMA; 
           [0019]      FIG. 4  is an isometric view of a top plate of a prior art LOMA showing a prior art metering valve in place; 
           [0020]      FIG. 5  is a cross-sectioned view of a top plate of a prior art LOMA showing a prior art metering valve in place; 
           [0021]      FIG. 6  is a cross-sectioned view of a first embodiment of a LOMA in accordance with the invention; 
           [0022]      FIGS. 7 and 8  are isometric views of the OCV tower as shown in  FIG. 5 , in accordance with the invention; 
           [0023]      FIG. 9  is a cross-sectioned view of a second embodiment of a LOMA in accordance with the invention; 
           [0024]      FIG. 10  is a cross-sectioned view of a LOMA with a full depth oil supply gallery, in accordance with a third embodiment of the present invention; 
           [0025]      FIG. 11  is an isometric view of a carrier with an integral oil supply gallery, in accordance with the third embodiment of the invention; 
           [0026]      FIG. 12  is a cross-sectioned view of a LOMA with a partial depth oil supply gallery, in accordance with the third embodiment of the present invention; 
           [0027]      FIG. 13  is a cross-sectioned view of another embodiment of a LOMA in accordance with the invention; 
           [0028]      FIG. 14  is a cross-sectioned view of still another embodiment of a LOMA in accordance with the invention; 
           [0029]      FIG. 15  is an isometric view of the restrictor/strainer assembly, in accordance with the invention; 
           [0030]      FIG. 16  is an isometric sectional view taken along line  13 - 13  in  FIG. 12 ; 
           [0031]      FIG. 17  is an isometric view of a top plate of a LOMA showing the restrictor/strainer assembly, in accordance with the invention, in place; and 
           [0032]      FIG. 18  is a cross-sectioned view of the restrictor/strainer installed between the valve plate and carrier, in accordance with the invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0033]    Referring to  FIG. 1 , the typical prior art engine oil circuit controlling a valve deactivation system for an internal combustion engine is shown. An engine control module (ECM)  2  receives input signals  4  from various sensors (not shown) and integrates via an algorithm such signals  4  with other input operating data such as oil temperature and engine speed to provide output signals  6  to energize or de-energize OCV  18 . While only one OCV  18  and two lifters  20  for a single cylinder are shown in the schematic drawing, it should be understood that valve deactivation is useful only in multiple-cylinder engines for selectively reducing the number of combusting cylinders. Multiple-cylinder embodiments are discussed below. 
         [0034]    In  FIG. 1 , an oil pump  10  feeds oil at a pressure of about 25-65 psi from sump  12  to a juncture  14  where the flow is split into at least two passages. A first passage  16  provides supply oil at a pressure of about 25-65 psi to the OCV  18 . When OCV  18  is closed (as shown), oil supply passage  16  is deadheaded at the OCV  18 . A second passage  22  from juncture  14  provides control oil via a passage segment  22   a  through metering valve orifice  24  whereby the oil pressure is reduced to about 1-2 psi in a passage segment  22   b . Metering orifice  24  is configured in flow series with oil control passage  22  and may be about 0.5 mm in diameter. With OCV  18  closed, oil flows through control passage  22  in a first direction  25  toward deactivation lifters  20 , at a reduced pressure, then through oil exhaust passage  26  where it is dumped back into the engine&#39;s oil reservoir  28 . The deactivation lifters  20  are calibrated to deactivate when the pressure in oil supply passage  16  is above about 25 psi and to activate when the pressure in oil control passage  22   b  is below about 2 psi. With the OCV  18  closed, deactivation lifters  20  are in their activation mode. With OCV  18  open, the oil in supply oil passage  16  flows in a second direction  30  toward deactivation lifters  20 , at a pressure above about 25 psi. As can be seen, metering valve  24  causes the line pressure in passage  22  to drop below a threshold pressure to cause the lifter to return to an activated mode. In the known prior art, metering valve orifice  24  is not immediately protected by a filter so that machining debris from the LOMA can migrate to orifice  24  and clog the metering passage. 
         [0035]    The benefits and advantages of an improved LOMA in accordance with the invention may be best appreciated by first considering a prior art LOMA  38  as shown in  FIGS. 2-5 . ( FIG. 3  shows the LOMA in its installed position on the engine and  FIG. 2  shows the LOMA inverted for clarity of component description). Prior art LOMA  38  includes a top plate  40 , a valve plate  42 , and a carrier  44  sandwiched between the top plate  40  and valve plate  42 . Typically, the top  40  and valve  42  plates are formed by die casting of aluminum; the carrier  44  is formed of a composite material selected to optimize sealability and support. The two plates  40 ,  42  and carrier  44  are held together by fasteners  46  to form a complex oil distribution manifold. LOMA  38  also includes OCVs  18  and an electrical lead frame  32  for receiving electrical signals  6  from ECM  2  through connector  34  and transmitting the signals  6  to the OCVs  18 , to open and close the valves as commanded by ECM  2 . 
         [0036]    When assembled, LOMA  38  may be installed into an internal combustion engine  36 , for example, via bolts  48  extending through bores in top plate  40  and being secured, for example, onto engine block towers provided along opposite sides of the valley of a V-style engine, for operative control of the deactivation lifters  20  ( FIG. 1 ) of the engine  36 . 
         [0037]    Carrier  44  is provided with a plurality of bores  50  extending completely through carrier  44  at selected locations for connecting oil passages in top plate  40  with oil passages in valve plate  42 . Carrier  44  further includes patterns of resilient sealing beads  45  for sealing the LOMA  38  against the surface of the engine block  36  and between the mating surfaces of the top  40  and valve  42  plates to prevent oil leakage and “cross-talk” between oil supply passage  16 , oil control passage  22 , and oil exhaust passage  26 . Typically, the patterns of sealing beads  45  are disposed in shallow grooves in surfaces of the carrier  44  into which the beads  45  may be fully compressed when LOMA  38  is assembled. 
         [0038]    The oil passages  16 ,  22 , and  26  in plates  40  and  42  and in carrier  44  and the sealing bead  45  patterns cooperate to define and form the oil galleries of a complex three dimensional LOMA  38  for selectively distributing pressurized oil from the block of engine  36  through an oil riser  70  to each of the plurality of OCVs  18  received in stepped sockets  72  formed in valve towers  73  of valve plate  42 . OCVs  18  extend through valve plate  42  and the valve heads thereof seal against seats  52  on the underside of carrier  44 . Stepped wells  54  and  56  are formed into the metal sockets  72 , in secondary machining and finishing steps, after valve plate  42  is cast and provide a sealing surface for OCV o-rings  58  once the OCVs  18  are installed into the sockets  72 . Each of the OCVs  18  controls the activation and deactivation of all valve lifters  20  for a given cylinder of a multi-cylinder engine via outlet ports  62  (one for the intake valve and one for the exhaust valve for each cylinder that is de-activatable) in LOMA  38 ; thus, four control valves  18  are required, for example, to deactivate valves for four cylinders of an eight-cylinder engine. 
         [0039]    Oil is distributed along the manifold from riser  70  via a global supply gallery, which connects via bores (not shown) to OCVs  18 . Riser  70  may be provided with an inline strainer (not shown) for catching debris trapped in the oil coming from the engine oil sump  12 . Referring to  FIG. 3 , when OCV  18  is energized to open, oil is admitted past the OCV seat  52  and upwards through oil control drilling  60  in the valve plate for supplying the deactivation valve lifters  20 . When OCV  18  is de-energized, oil flows continually through oil exhaust passage  26  back into the engine oil reservoir  28  ( FIG. 1 ). This arrangement keeps oil control passage  22  filled with oil and thus prevents entry of air into the supply lines leading from the control valves  18  to the deactivation lifters  20  ( FIG. 1 ). 
         [0040]    A retainer  84 , such as for example a c-clip, seated in a corresponding groove  86  formed in the inside wall of stepped socket  72  holds the OCVs  18  in their respective sockets  72 . The installed inside diameter of retainer  84  is smaller than the outside diameter of OCV flange  88  thereby keeping the OCV  18  in place. A separate spring  90 , such as a metal wave washer, disposed between flange  88  and retainer  84  loads the OCV  18  against valve plate  42 . 
         [0041]    Referring specifically to  FIGS. 4 and 5 , a typical prior art separate metering valve  24  is shown installed in series with oil control passage  22  formed in top plate  40 . The general body  74  of valve  24  is formed of die cast metal, as for example zinc, and orifice restrictor  76  is precision machined into body  74  in a separate step following the die casting process. A pocket  78 , assuming the thickness and shape of metering valve body  74 , is machined into oil control channel  22  to press-fittedly receive metering valve  24 . A cast shelf  80  also machined into oil control channel  22  serves to limit the depth in which valve  24  may be pressed into pocket  78  to thereby assure that a good and flat sealing surface remains between top plate  40  and carrier  44 . As mentioned previously, a strainer (not shown) is typically positioned remote and well upstream from metering valve  24 , such as at the interface between the block of engine  36  and the LOMA  38  near riser  70 , for catching debris trapped in the oil coming from the engine oil sump  12  ( FIG. 1 ). Chips and debris left from the various processes performed in machining and manufacturing LOMA  38  cannot be trapped by the strainer because of its location and are permitted to migrate toward and collect at the orifice restrictor  76 . The strainer may further be molded in place, welded, snapped in place, or bonded in some other manner. 
         [0042]    Referring to  FIGS. 6-8 , an improved LOMA  138  representing a first embodiment of the invention in which the OCV socket towers are formed as separate non-metal components is shown. (Note: features identical with those in prior art LOMA  38  carry the same numbers; features analogous but not identical carry the same numbers but in the 100 series.) Improved LOMA  138  includes a revised top plate  140 , a revised valve plate  142 , and a revised carrier  144  sandwiched between the top plate  140  and valve plate  142 . As before, the top  140  and valve  142  plates are preferably formed by die casting of aluminum. However, OCV socket towers  173  are formed as separate components, are preferably molded of a heat stabilized polymer such as nylon 66, and are held in place by valve plate  142 , as will be explained in more detail below. An aspect of the invention is that sockets  172  and particularly stepped wells  154  and  156  are as-molded without the need for secondary machining. As-molded surfaces of stepped wells  154  and  156  provide a sealing surface for OCV o-rings  58  once the OCVs  18  are installed into the sockets  172 . Flange ears  164  at the base of each molded tower  173  extend radially outward from the base of the tower  173  and fit into similarly shaped pockets  165 , formed in the carrier  144 . Similarly shaped recesses  166  are formed in the mating surface of valve plate  142  so that, when the LOMA is assembled, tower  173  is trapped in place between the top plate  140  and valve plate  144 . Resilient seal  167  serves to seal oil supply  116 , oil control  122 , and oil exhaust  126  passages from each other and further serves to take up any tolerances between the thickness of flange ears  164  and the gap for ears  164  provided by pockets  165  and recesses  166 . A clocking feature, such as, for example, making the width  168   a  of one of the flange ears of a different size than the width  168   b  of the other ear to assure that oil passages  122 ,  126 , formed in tower  173  will align properly with the associated passage  122  or  126  formed in carrier  144  and top plate  140  when the tower is assembled into LOMA  138 . 
         [0043]    The two plates  140  and  142 , carrier  144 , and OCV  18  are held together by fasteners  46  to form LOMA  138 . Note that an inward facing flange  184 , formed as part of valve plate  142 , serves to keep OCV  18  in place after LOMA  138  is assembled thereby replacing retainer  84  and machined groove  86  in the prior art. The axial height  169  of tower  173 , including the thickness of resilient seal  167  extending below the bottom surface of tower  173 , and the thickness of OCV flange  88 , are sized to be slightly less than the axial length provided for the tower between the bottom surface of pocket  165  and the underside of valve plate flange  184 . The slight clearance may be taken up by separate spring  90 , such as for example a metal wave washer, disposed between OCV flange  88  and valve plate flange  184  and to thereby load the OCV  18  against socket tower  173  and carrier  144 . LOMA  138  also includes electrical lead frame  32  for receiving electrical signals  6  from ECM  2  through connector  34  and transmitting signals  6  to OCVs  18 . After assembly, LOMA  138  may be installed into an internal combustion engine  36 , for example, via bolts  48  extending through bores in top plate  140  and being secured, for example, onto engine block towers provided along opposite sides of the valley of a V-style engine. 
         [0044]    Referring to  FIG. 9 , an improved LOMA  238  representing a second embodiment of the invention in which the OCV socket towers are formed integral with the carrier plate is shown. (Note: features identical with those in prior art LOMA  38  and first embodiment LOMA  138  carry the same numbers; features analogous but not identical carry the same numbers but in the 200 series.) Improved LOMA  238  includes a revised top plate  240 , a revised valve plate  242 , and a revised carrier  244  sandwiched between the top  240  and valve  242  plates. The top  240  and valve  242  plates are preferably formed by die casting of aluminum. Differing from LOMA  138 , OCV socket towers  273  are formed integral with carrier  244  and, together, are preferably molded of a heat stabilized polymer such as nylon 66 as a single part. An aspect of the invention is that sockets  272  and stepped wells  254  and  256  are molded into socket towers  273  without the need for secondary machining. As-molded surfaces of wells  254  and  256  provide a sealing surface for OCV o-rings  58  once the OCVs  18  are installed into sockets  272 . A recess  266  is formed in the mating surface of top plate  240  so that, when LOMA  238  is assembled, the footprint of integrated carrier/tower  244  is close-fittedly received in the recess  266  and carrier/tower  244  is trapped in place between the top plate  240  and valve plate  242 . Resilient seals  267  serve to seal oil supply  216 , oil control  222  and oil exhaust  226  passages from each other and further serve to take up any tolerances between the thickness of foot print flange  264  and the gap for the flange provided by recess  266 . 
         [0045]    The two plates  240 ,  242 , carrier  244 , and OCV  18  are held together by fasteners  46  to form LOMA  238 . Note that an inward facing flange  284 , formed as part of valve plate  242 , serves to keep OCV  18  in place after LOMA  238  is assembled thereby replacing retainer  84  and machined groove  86  in the prior art. The axial height of tower  273 , including the thickness of resilient seal  267  extending below the bottom surface of tower  273 , and the thickness of OCV flange  88 , are sized to be slightly less than the axial length provided for the tower between the bottom surface of recess  266  and the underside of valve plate flange  284 . The slight clearance may be taken up by separate spring  90 , such as for example a metal wave washer, disposed between OCV flange  88  and valve plate flange  284  and to thereby load OCV  18  against carrier  244 . LOMA  238  also includes electrical lead frame  32  for receiving electrical signals  6  from ECM  2  through connector  34  and transmitting signals  6  to OCVs  18 . 
         [0046]    Referring to  FIGS. 10 through 11 , an improved LOMA  638  with a full depth oil supply gallery representing a third embodiment of the present invention in which the oil supply passage is integral to the carrier is shown. (Note: features identical with those in prior art LOMA  38 , first embodiment LOMA  138 , and second embodiment LOMA  238  carry the same numbers; features analogous but not identical carry the same numbers but in the 600 series.) Improved LOMA  638  includes a revised top plate  640 , a valve plate  642 , and a revised carrier  644  sandwiched between top plate  640  and valve plate  642 . Carrier  644  includes an integral oil supply passage  616  having a full depth  617 . 
         [0047]    Valve plate  642  is comparable to valve plate  242  shown in  FIG. 9 . The top  640  and valve  242  plates are preferably formed by die casting of aluminum. 
         [0048]    Analogous to LOMA  238  shown in  FIG. 9 , OCV socket towers  273  are formed integral with carrier  644  and, together, are preferably molded of a heat stabilized polymer such as nylon 66 as a single part. Sockets  272  and stepped wells  254  and  256  are molded into sockets  272  without the need for secondary machining. As-molded surfaces of wells  254  and  256  provide a sealing surface for OCV o-rings  58  once the OCVs  18  are installed into sockets  272 . A recess  266  is formed in the mating surface of top plate  240  so that, when LOMA  638  is assembled, the footprint of integrated carrier/tower  644  is close-fittedly received in the recess  266  and carrier/tower  644  is trapped in place between the top plate  640  and valve plate  642 . Resilient seals  267  serve to seal oil supply  716 , oil control  222 , and oil exhaust  226  passages from each other and further serve to take up any tolerances between the thickness of foot print flange  264  and the gap for the flange provided by recess  266 . Furthermore, assembly of plates  640  and  642 , carrier  644 , and OCVs  18  to form LOMA  638  is similar to the assembly of LOMA  238  as described above in connection with  FIG. 9 . 
         [0049]    Differing from LOMA  238  shown in  FIG. 9 , oil supply passage  616  is integrated into carrier  644  instead of into top plate  640 . Accordingly, top plate  640  of LOMA  638  does not include an oil supply passage  216  as does top plate  240  of LOMA  238  ( FIG. 9 ). Integrating oil supply passage  616  into carrier  644  in accordance with the third embodiment of the present invention, results in an oil supply path and an oil control path in different surfaces. 
         [0050]    As shown in  FIG. 11 , socket towers  273  and oil supply passage  616  are formed integral with carrier  644  as a single integral part. Oil supply passage  616  may be a groove or channel that is integrated into carrier  644 , for example, molded into carrier  644 , thus, eliminating any secondary machining operations. Oil supply passage  616  leads directly to socket  272  and, therefore, to OCV  18  when installed. No changes to socket tower  273  are needed compared to LOMA  238  shown in  FIG. 9 . Oil supply passage  616  extends vertically all the way to the surface of carrier  644  that mates with top plate  640 . Accordingly a maximum depth  617  of oil supply passage  616  can be achieved. 
         [0051]    Referring to  FIG. 12 , an improved LOMA  738  with a partial depth oil supply gallery representing the third embodiment of the present invention in which the oil supply passage is integral to the carrier is shown. (Note: features identical with those in prior art LOMA  38 , first embodiment LOMA  138 , and second embodiment LOMA  238  carry the same numbers; features analogous but not identical carry the same numbers but in the 700 series.) Improved LOMA  738  includes a revised top plate  740 , a valve plate  742 , and a revised carrier  744  sandwiched between top plate  740  and valve plate  742 . Carrier  744  includes an integral oil supply passage  716  having a partial depth  717 . Valve plate  742  is comparable to prior art valve plate  42  shown in  FIG. 3 . As before, the top  740  and valve  742  plates are preferably formed by die casting of aluminum. 
         [0052]    Analogous to prior art LOMA  38  shown in  FIG. 3 , OCV socket towers  73  are formed integral with valve plate  742  as is explained in more detail above. 
         [0053]    Differing from prior art LOMA  38  shown in  FIG. 3 , oil supply passage  716  is integrated into carrier  744  instead of into top plate  40 . Accordingly, top plate  740  of LOMA  738  does not include an oil supply passage  116  as does top plate  40  of LOMA  38  ( FIG. 3 ). Integrating oil supply passage  716  into carrier  744  in accordance with the third embodiment of the present invention, results in an oil supply path and an oil control path in different surfaces. Oil supply passage  716  is formed integral with carrier  744  as a single integral part. Oil supply passage  716  may be a groove or channel that is formed in carrier  744 , for example, by a secondary machining operation, such that an open end of the groove faces socket  72 . Oil supply passage  716  leads directly to sockets  72  and, therefore, to OCV  18  when installed. Contrary to oil supply passage  616 , oil supply passage  716  is formed in carrier  744  such that the channel or groove does not extend vertically all the way to the surface of carrier  744  that mates with top plate  740 . As a result, the depth  717  of oil supply passage  716  is less than the depth  617  of oil supply passage  616  and it may be possible to eliminate resilient seals  267  ( FIG. 10 ) that surround oil supply passage  616  of LOMA  638 . 
         [0054]    While the oil supply passage is shown integrated into the carrier of LOMA  238  and into the carrier of prior art LOMA  38 , it is understood that the third embodiment of the invention could also be used in conjunction with LOMA  138 . Accordingly, it may be possible to integrate oil supply passage  116  of LOMA  138  ( FIG. 6 ) into carrier  144  instead of into top plate  140  as shown in  FIG. 3 . Oil supply passage  116  may be integrated into carrier  144  to have a full depth  617  or a partial depth  717 . 
         [0055]    Referring now to  FIGS. 13 and 14 , additional aspects of an improved LOMA, in accordance with the invention, are shown. In these figures, separate spring  90  is replaced with spring member  390  formed either integrally with OCV  318  ( FIG. 13 ) or spring member  490  formed integrally with socket tower  473  ( FIG. 14 ). In both cases, the spring member is formed of the same material used to form the body of OCV  318  or socket tower  473 . The size, shape, and stiffness of integrated spring member  390 ,  490  could be readily determined by one skilled in the art without undue experimentation. While the integrated spring member  390  is shown in  FIGS. 13 and 14  in reference to LOMAs  238  and  638  (shown in  FIGS. 6 and 12 , respectively) having the OCV tower formed integral with the carrier, it is understood that this aspect of the invention could also be used in conjunction with LOMAs  138  and  738  (shown in  FIGS. 9 . and  10 , respectively) or in conjunction with the prior art LOMA  38  shown in  FIG. 3 . 
         [0056]    In yet another aspect of the invention, the metal die-cast metering valve  24  (as shown in  FIGS. 1 and 4 ) is replaced with a metering valve molded of a non-metallic material requiring no after-molding machining and having an integrated strainer. Referring again to  FIG. 1 , the prior art LOMA hydraulic circuit includes metering valve  24  disposed in series with oil control passage  22 . Orifice restrictor  76  ( FIG. 5 ) is precision machined into body  74  of metering valve  24  before the valve is pressed into pocket  78  of top plate  42  ( FIGS. 4 and 5 ). Orifice restrictor  76  serves to reduce the line pressure in passage  22  from a level of about greater than 25 psi upstream of valve  24  to a level of about less than 2 psi. To achieve the needed pressure drop across the valve, orifice restrictor  76  must be exceptionally small—in the order of about 0.5 mm in diameter. It is known in the art to place a separate strainer in the circuit well upstream of the restrictor in order to trap debris in the engine lubricating oil. However, placing the strainer remote from the restrictor does not serve to trap debris, such as chips and flashing left in the LOMA during its manufacturing process. This debris is known to migrate toward and clog the restrictor that otherwise could not be trapped by the prior art remotely located strainer. By integrating with the metering valve so that the orifice restrictor is close to the strainer, the orifice restrictor is better protected from all trapped debris including debris from within the LOMA. The strainer can be molded in place, welded, snapped in, or bonded in some other manner. 
         [0057]    Referring to  FIGS. 15-18 , an integrated orifice restrictor/strainer (ORS) is shown. ORS  500  includes hollow elongate body  512  having generally planar top plate surface  512  and stepped carrier surface  514 . Planar top plate surface  512  defines lateral seal channel  516  disposed at approximately a midpoint between sides  518 ,  520  of body  510 . Between channel  516  and side  520 , surface  512  defines restrictor orifice  524 . Between channel  516  and side  518 , surface  512  defines strainer member  526 . Referring to  FIG. 15 , restrictor  524  is in fluid communication with strainer  526  via internal flow chamber  528 . Other than through orifice restrictor  524  and strainer  526 , fluid chamber  528  is sealed from the outside of body  510 . ORS may be formed entirely as shown, in the molding process, without additional machining or fabricating, as known in the art. 
         [0058]    Referring now to  FIG. 17 , top plate  540 , including control passage  522  formed in top plate  540  is shown. Also shown, in transparent view is ORS  500  positioned over control passage  522 . Control passage  522  is modified from passage  22  shown in  FIG. 4  in that dam  530  has been added completely blocking off the cross section of passage  522  between passage segment  522   a  upstream of ORS  500  and passage segment  522   b  downstream of ORS  500 . ORS provides a bridged passageway over dam  530 , as will now be described. 
         [0059]    Referring to  FIG. 18 , ORS  500  is shown residing adjacent top plate  540 . Pressurized oil  532  from pump  10  ( FIG. 1 ) flows (from left to right in  FIG. 18 ) through oil control passage  522  through strainer  526 , where debris from the LOMA can be trapped, up through chamber  528 , then returning to passage  522   b  through orifice restrictor  524 . From there oil at a reduced pressure flows to the deactivation lifters  20  ( FIG. 1 ). To prevent undesirable leakage of oil between dam  530  and channel  516 , a resilient sealant  534  may be applied to either the dam of the channel surface. 
         [0060]    ORS  500  may be molded as a separate component as shown in  FIGS. 15 ,  16 , and  18 , or may be molded integrally with carrier  544 . It is understood that the embodiment shown in  FIGS. 15-18  may be used in conjunction with any of the other embodiments shown herein, in accordance with the invention, or may be used in conjunction with the prior art LOMA, either molded separately of integrally with carrier  44 . 
         [0061]    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.