Abstract:
A hydraulic manifold assembly for variable actuation of engine valves. First and second plates have portions of flow passages integrally molded therein. The plates are formed preferably by injection molding of a suitable polymer, for example, glass-filled PPA, and are joined together as by cementing or preferably by fusion welding along mating surfaces to form the full pattern of flow passages. The assembly further comprises a retainer for retaining a plurality of individual solenoid-actuated valves in sockets formed in the plates. The retainer is similarly formed preferably by injection molding of a suitable polymer and is formed to function simultaneously as a positive crankcase ventilation (PCV) baffle.

Description:
TECHNICAL FIELD 
     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 assembly for retaining the solenoid deactivation control valves and for providing positive crankcase ventilation (PCV). 
     BACKGROUND OF THE INVENTION 
     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. 
     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and that at low-demand times fuel efficiency could be improved if one or more cylinders of a larger engine could be withdrawn from firing service.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 assembly that utilizes electric solenoid valves to selectively pass engine oil to the lifters upon command from an engine control module (ECM). Such a manifold assembly is often referred to in the art as a Lifter Oil Manifold Assembly (LOMA). 
     It is a principal object of the present invention to provide an assembly for retaining the solenoid valves and for positive crankcase ventilation comprising a minimum number of components which then may be easily fabricated, and preferably which are formed of a suitable thermoplastic polymer such that the components may be fusibly joined without threaded fasteners as by vibration welding. 
     SUMMARY OF THE INVENTION 
     Briefly described, a hydraulic manifold assembly for variable actuation of engine valves includes first (top) and second (bottom) plates having portions of oil flow passages, or galleries, integrally molded therein. The plates are formed preferably by injection molding of a suitable high temperature thermoplastic polymer. The plates are joined together as by cementing or preferably by fusion welding (vibration welding) along mating surfaces, obviating the need for separate fasteners and for internal seals on the flow passages. The hydraulic manifold assembly further comprises a retainer for retaining a plurality of individual solenoid-actuated valves in operational disposition in sockets formed in the plates. 
     In accordance with this invention, the retainer is also formed of a moldable polymer and with air passageways so as to function simultaneously as a PCV baffle that attaches to the hydraulic manifold assembly via integrally molded releasable snap clips. Alternatively, the retainer can be attached to a polymer hydraulic manifold assembly or to a conventional metal hydraulic manifold assembly via bolts or similar attachment means. The present invention results in a weight savings and a substantial savings in be manufacturing cost over prior art assemblies formed of cast aluminum. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     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: 
     FIG. 1 is a schematic drawing of an oil system for an internal combustion engine showing the relationship of a valve deactivation control system in accordance with the invention; 
     FIG. 2 is an exploded isometric view from above of a prior art hydraulic manifold assembly; 
     FIG. 3 is an exploded isometric view from above of a hydraulic manifold assembly or LOMA with connected solenoid retainer/PCV retainer in accordance with the invention; 
     FIG. 4 is a side elevational view of the LOMA shown in FIG. 3; 
     FIG. 5 is an end elevational view of the LOMA shown in FIG. 3; 
     FIG. 6 is a cross-sectional view taken along line  6 — 6  in FIG. 11; 
     FIG. 7 is a cross-sectional view taken along line  7 — 7  in FIG. 11; 
     FIG. 8 is a bottom view of the upper plate in the assembly shown in FIG. 3; 
     FIG. 9 is a top view of the lower plate in the assembly shown in FIG. 3; 
     FIG. 10 is a bottom view of the lower plate in the assembly shown in FIG. 3; 
     FIG. 11 is a bottom view of the assembly shown in FIG. 4; 
     FIG. 12 is a detailed cross-sectional view taken through a portion of the assembly shown in FIG. 4, showing fusing of the upper and lower plates along mutual mating surfaces; and 
     FIG. 13 is a cross-sectional view of the retainer/PCV baffle (upper element) of an alternate embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, the engine oil circuits for an internal combustion engine are provided with a valve deactivation control circuit in accordance with the invention. While only a single control valve and lifter 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. In FIG. 1, an oil pump  10  feeds oil from sump  12  to a juncture  14  where the flow is split three ways. A first portion  16  provides conventional general lubrication to the engine. A second portion  18  provides oil conventionally to the hydraulic valve lash adjusters  19 , which support valve deactivation lifters  20 . A third portion  22  provides oil to a valve deactivation control system  24 . An optional pressure relief valve  26  is openable to the sump to maintain pressure in system  24  at a predetermined maximum level. Oil is filtered by strainer  28  and then is supplied to a solenoid control valve  30  wherein it is either diverted to the sump  12  if the control valve  30  is not energized, or is diverted to deactivation lifter  20  if the control valve  30  is energized, to cause the associated engine intake and exhaust valves to be deactivated. An ECM  32 , preferably mounted on other than the engine, receives input signals  33  from a pressure transducer  34  in the control system  24  and integrates via an algorithm such signals with other input operating data such as oil temperature and engine speed to provide output signals  36  to energize or de-energize solenoid control valve  30 . 
     Referring to FIG. 2, a prior art hydraulic manifold assembly  38 , including solenoid valve retainer  84  are shown. Manifold assembly  38  includes a top plate  40 , a bottom plate  42 , and a gasket plate  44  sandwiched between the top and bottom plates. Typically, at least the top and bottom plates are formed by investment casting of aluminum. The three plates are held together by bolts  46  to form a complex oil distribution manifold  38  as described below. When assembled, manifold assembly  38  may be conveniently installed into an internal combustion engine, for example, via bolts  48  extending through bores in top plate  40  and gasket plate  44  and being secured, for example, onto engine block towers provided along opposite sides of the valley of a V-style engine (not shown) for operative control of the deactivation lifters of the engine. 
     A first pattern of passages (not visible) is formed in the underside  51  of top plate  40 , which may be expressed as a corresponding pattern of ridges  52  on the upper surface thereof. Similarly, a second pattern of passages  54  is formed in the upper surface  55  of bottom plate  42 . Gasket plate  44  is provided with a plurality of bores extending completely through the plate at selected locations for connecting passages in top plate  40  with passages in bottom plate  42 . The upper surface  58  and the lower surface  60  of gasket plate  44  are further provided with respective patterns of resilient gasketing material generally in the shape of the patterns of passages and bores in the top and bottom plates. Typically, the gasketing patterns are disposed in shallow grooves in surfaces  58 , 60  into which the gasketing material may be fully compressed when manifold assembly  38  is assembled. 
     The oil passages and gasketing patterns in plates  40 , 42 , 44  cooperate to define and form the oil galleries of a complex three dimensional hydraulic manifold assembly  38  for selectively distributing pressurized oil from an oil riser  70  to each of four solenoid control valves  30  received in sockets  72  formed in bottom plate  42 . Control valves  30  extend through bottom plate  42  and the valve heads thereof seal against seats (not shown) on the underside of gasket plate  44 . Each of the control valves  30  controls the activation and deactivation of all valve lifters for a given cylinder of a multi-cylinder engine via outlet ports (not visible) in manifold assembly  38 ; thus, four control valves are required, for example, to deactivate valves for four cylinders of an eight-cylinder engine. 
     Oil is distributed along the manifold assembly from riser  70  via a global supply gallery  76  which connects via bores  78  in gasket plate  44  to control valves  30 . Riser  70  may be provided with an inline strainer housing  71  for ready replacement of strainer  28 . When a valve  30  is energized to open, oil is admitted past solenoid valve  30  and upwards through plate  44  via bore  75  into an individual supply gallery  80  for supplying two deactivation valve lifters via bores  79 . 
     Retainer  84  holds the solenoid control valves  30  in their respective sockets  72 . Retainer  84  is typically cast of a high-temperature dielectric plastic and is provided with integral standoffs  92  through which it is bolted into top plate  40 . 
     Referring to FIGS. 3 through 7, an improved hydraulic manifold assembly or LOMA  138  is shown. (Note: features identical with those in prior art manifold assembly  38  carry the same numbers; features analogous but not identical carry the same numbers but in the 100 series; and new features are shown in the 200 series.) LOMA  138  includes a top plate  140 , bottom plate  142 , solenoid valves  30 , and retainer/PCV baffle  184 . A perimeter gasket  98  is preferably used to seal top plate  140  against an engine (not shown) when LOMA  138  is attached by bolts  48  onto the valley of a V-style engine. 
     According to the present invention, retainer  184 , which also is a PCV baffle as described in more detail below, is formed in an upper element  94  and a lower element  96  which are then joined along their mating edges as described below to form retainer/PCV baffle  184 . Preferably, retainer/PCV baffle  184  is formed having flexible barbed tabs  95  protruding upwards from upper element  94  for engaging with mating catches  97  to secure retainer/PCV baffle  184  to bottom plate  142 , thereby retaining solenoid valves  30  in proper position in sockets  172 . In an alternative embodiment, retainer/PCV baffle  184  can be secured to bottom plate  42  or top plate  40  of prior art control manifold assembly  38  or to plates  140  or  142  of improved LOMA  138  with threaded fasteners. 
     Referring to FIGS. 8,  9 ,  11 , and  12 , in a currently preferred method for attaching top plate  140  to bottom plate  142 , top plate  140  is provided on its underside  151  with a continuous planar first mating surface  200  formed in a first pattern delineating the upper portions of various oil flow galleries in LOMA  138 . Bottom plate  142  is provided on its upper side  155  with a planar second mating surface  202  formed in a second pattern which is generally the mirror image of the first pattern. Surface  202  is bounded on either side by first and second grooves  204 , 206  (FIG.  12 ). Top plate  140  and bottom plate  142  preferably are formed of a thermoplastic polymer having a relatively high melting temperature, for example, a glass-filled poly phthalamide (PPA). The top and bottom plates are joined along mating surfaces  200 , 202  preferably by fusion, and preferably by vibration welding wherein the plates are urged together, preferably at a loading of about 200-400 pounds per square inch, preferably about 300 pounds per square inch of mating surface, and are vibrated past each other, preferably at a frequency of about 120-240 Hz. Under these conditions, surfaces  200 , 202  liquefy, compress, and fuse in a fusion zone  208 , forming a mechanical and hermetic seal defining the oil galleries in a subassembly  205  (FIG. 11, shown with retainer/PCV baffle  184  also attached). Polymer squeezed out of zone  208  is collected in grooves  204 , 206  which function as “flash traps.” Preferably, zone  208  is compressed to a predetermined extent, preferably about 0.030-0.070 inch. 
     Referring to FIG. 10, the underside  210  of bottom plate  142  is formed having ports  212  for receiving resilient circular oil seals  214  (also FIG. 3) for sealing to the actuating oil passages (not shown) controlled by the manifold. 
     Referring again to FIG. 3, as described above, in addition to securing solenoid valves  30  into bottom plate  142 , retainer  184  may also be configured as a PCV baffle. Upper and lower elements  94 , 96  are preferably formed of a high-temperature thermoplastic by injection molding, similarly to top and bottom plates  140 , 142 , and are similarly fused along planar mating surfaces by vibration welding to yield retainer/PCV baffle  184 . Preferably, upper and lower elements  94 ,  92  are formed of a thermoplastic polymer having a relatively high melting temperature, for example, a glass filled PPA. Upper and lower elements  94 ,  96  are joined along their mating surfaces, preferably by vibration welding wherein the plates are urged together at a loading of about 200-400 pounds per inch of mating surface and are vibrated past each other, preferably at a frequency of about 120-240 Hz. “Flash trap” grooves, similar to those shown as numerals  204 ,  206  in plate  142  (FIG. 12) can be formed in one of either mating surfaces of elements  92 ,  94  to facilitate the formation of a mechanical, hermetic seal between elements  92 ,  94 . 
     The resulting retainer/PCV baffle includes a supportive bucket  216  for retaining each solenoid valve. The buckets are attached to a generally hollow sinusoidal member  218  having an entry aperture  220  and an exit fitting  222  matable with a port  224  and fitting  226  (FIGS. 3 and 8) for connection to the intake manifold (not shown) of the engine. Preferably, the interior of member  218  is provided with a series of offset baffles  228  forming a labyrinthine pathway through member  218  for separation of oil droplets from air as crankcase and valve blowby is drawn through member  218  by intake manifold vacuum. Separated oil droplets agglomerate within member  218  and run back into the engine via entry aperture  220 . As described above, retainer/PCV baffle  184  is preferably provided with tabs  95  protruding upwards from upper element  94  for engaging with mating catches  97  to secure retainer/PCV baffle  184  to bottom plate  142 , thereby retaining solenoid valves  30  in proper position in sockets  172 , as shown in FIGS. 5 through 7. 
     As briefly described above, upper element  94 ′ of a second retainer/PCV baffle embodiment  184 ′, as shown in FIG. 13, is formed without tabs  95  and instead is provided with a plurality of hollow fastener compression tubes  192 . Retainer/PCV baffle  184 ′ may then be secured to either plates  40  or  42  of prior art metal manifold assembly  38  or plates  140  or  142  of improved polymer LOMA  138  by bolts  46  (as in FIG.  2 ), or equivalent fasteners. The compression tubes may be formed in both the upper and lower elements, may be formed as molded polymer features in the element(s), or may be formed of metal and pressed or molded into the polymer element(s) as known in the art. Thus, PCV capability can easily be provided to prior art manifold assembly  38  by substitution of retainer/PCV baffle  184 ′, for retainer  84 . 
     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.