Abstract:
An electro-hydraulic control module for deactivating and reactivating intake and exhaust valves in an internal combustion engine comprising a series of stacked plates that form hydraulic valves, manifolding for supply, control and exhaust hydraulic flow and supports electromagnetic solenoids for activating the hydraulic valves. The plate structure is economical to manufacture and is advantageously small in vertical size. A bleed circuit keeps the hydraulic system relatively free of air to achieve fast, reliable and repeatable performance.

Description:
This application claims priority of U.S. Provisional Application No. 60/193,121, filed Mar. 30, 2000, and U.S. Provisional Application No. 60/197,728, filed Apr. 18, 2000, the disclosures of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to apparatus for deactivating a limited number of cylinders in a multi-cylinder internal combustion engine. 
     PRIOR ART 
     Automotive engines have the ordinarily conflicting demands of providing high power capacity and good fuel economy. To achieve these needs, intake and exhaust valve deactivation to turn off some of the cylinders in a V-8 or V-6 engine has been attempted for a number of years. In the past, this approach has not been fully successful with consumers because the ability to rapidly respond to a vehicle&#39;s power needs has not always been reliable. With the evolution of a multitude of sensors in modern vehicles and the centralization of inputs from these sensors into the engine control module, a potential to execute this valve deactivation strategy in an engine exists. 
     To implement this strategy in a V-8 engine, up to four of the cylinders are deactivated at one time to effectively change the engine from a V-8 to a V-4. This reduction in the number of cylinders which are working results in reduced fuel consumption and hence improved fuel economy. The cylinders are turned off by locking the inlet and exhaust valves into the closed position. This stops air from entering or exiting the cylinders and by not turning on the fuel injectors, the cylinders are completely turned off. The inlet and exhaust valves are locked into the closed position by advancing a pin through the valve which mechanically holds the valves closed. This pin force is balanced by hydraulic pressure on one end and a coil spring on the other. A need exists for an economical, reliable and compact system for deactivating and reactivating the valves through these pins in a nearly instantaneous manner. 
     SUMMARY OF THE INVENTION 
     The invention provides an electro-hydraulic control module for deactivating sets of intake and exhaust valves in an internal combustion engine. The invention provides a module that is small in size, particularly in height, and is economical to manufacture and in operation is fast, reliable, and repeatable. The module employs relatively thin plates to provide hydraulic flow paths and to carry the hydraulic valve elements and actuating solenoids. 
     More specifically, the plates include so called “worm trails” or passages that transmit supply, exhaust, and control pressures to and from the control valves. The plates, which can be conveniently bolted across the top plane of the central valley of a V-shaped engine block such as in a V-8 engine, suspend the actuating solenoids in the valley space. The disclosed hydraulic valves, one for each engine cylinder to be deactivated, are located in low profile multiple purpose plate structures and use an inexpensive spherical ball as the valving element. 
     In each of the disclosed embodiments, the solenoids are electrically connected with conductors carried in a common rigid connector frame to simplify assembly procedures and reduce costs. 
     The invention provides a novel bleed circuit for reducing and, preferably, eliminating air from the hydraulic control passages in the module and the so-called “pin towers” in the engine that lead to the intake and exhaust valve disabling pin elements. The reduction in air in the control passages greatly improves the speed and repeatability of the hydraulic circuit. Speed and repeatability are important in the application of the present invention, because only a very short time is available with the engine running at moderate or high speed when the valves are motionless and thereby susceptible to be mechanically disabled in a shockless, i.e. smooth, manner. Repeatability or predictability of function of the disclosed circuitry of the module of the invention enables an engine control module to anticipate when the engine valves will be stationary and to initiate hydraulic valve actuation in the electro-hydraulic module at an appropriate time before then to assure that the hydraulic functions are completed within the available time. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of an electro-hydraulic control module for deactivating intake and exhaust valves of an internal combustion engine in accordance with a first embodiment of the invention; 
     FIG. 2 is a side elevational view of the module of FIG. 1; 
     FIG. 3 is a bottom plan view of the module of FIG. 1; 
     FIG. 4 is an end elevational view of the module of FIG. 1; 
     FIG. 5 is a bottom plan view of a top plate and exhaust plug assembly of the module of FIG. 1; 
     FIG. 5 a  is a fragmentary cross-sectional view of the top plate taken in the plane  5   a — 5   a  indicated in FIG. 5; 
     FIG. 5 b  is a fragmentary cross-sectional view of the top plate taken in the plane  5   b — 5   b  indicated in FIG. 5 with an exhaust plug removed for clarity; 
     FIG. 6 is a longitudinal cross-sectional view of the top plate taken in the plane  6 — 6  indicated in FIG. 5; 
     FIG. 7 is a bottom plan view of a seal plate of the module of FIG. 1; 
     FIG. 8 is a cross-sectional view of the seal plate taken in the plane  8 — 8  indicated in FIG. 7; 
     FIG. 9 is a bottom plan view of a gasket seal plate assembly; 
     FIG. 10 is a bottom plan view of a typical pole plate; 
     FIG. 11 is a cross-sectional inverted view of a typical valve station taken in the bent plane indicated in FIG. 3 at  11 — 11  with a connector frame omitted for clarity; 
     FIG. 12 is a fragmentary exploded view from below of a portion of the top plate and a typical exhaust plug; 
     FIG. 13 is an exploded isometric view of an electro-hydraulic control module constructed in accordance with a second embodiment of the invention; 
     FIG. 14 is a somewhat schematic bottom view of a top plate of the module of FIG. 13 showing worm trails for supply, control and exhaust pressures; and 
     FIG. 15 is a schematic view of a typical valve and solenoid of the module of FIG. 13 in an inverted orientation. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings and, in particular, to FIGS. 1 through 4, there is shown a electro-hydraulic control module  10  for valve deactivation in an internal combustion engine in accordance with a first embodiment of the invention. The module  10  includes a generally planar plate assembly  11 . The term plate, when used as a noun herein, refers to a generally flat body that is relatively thin in one dimension compared to its size in the other two dimensions parallel to the plane of the body and that has planar surface areas on at least one face. The plate assembly  11  comprises, in sequence starting at the top with reference to the orientation of the assembly when it is installed on an engine, a top plate  12 , a seal plate  13  and a gasket seal plate  21 . The illustrated module  10  is arranged to be used on a V-8 engine and includes four hydraulic control valves (discussed below in connection with FIG. 11) individually actuated by respective electrical solenoids  16 . The solenoids  16  are energized by voltage applied through electrical conductors in a connector frame  17  that mates with a connector  18  having electrical pins or blades within its shroud as is generally known. 
     The top plate  12 , which is preferably cast aluminum, has its lower side formed with grooves or “worm trails” that establish flow paths or passages for hydraulic oil, typically in this application engine lubrication oil, that serves to hydraulically operate elements for deactivating selected cylinders of the internal combustion engine on which the module  10  is mounted. The top plate  12  receives pressurized oil at a supply port  22 . Supply pressure is conducted to centers  23  for valves described below in connection with FIG. 11 located above the solenoids  16  by trails  24  (FIG.  5 ). Control pressure from the valve centers  23  is conducted through trails  26 . Exhaust for oil pressure is conducted from the valve centers or stations  23  through trails  27 . A pressure relief valve  31 , integrated in the top plate  12  and of a generally conventional construction using a ball and spring, limits oil pressure in the supply, control and exhaust trails  24 ,  26  and  27  by dumping excess oil pressure into the valley of the engine below the module  10 . A pressure sensor  32 , of known construction, transmits electrical signals indicating the pressure of oil in the supply trails  24  to the engine control module or computer. The pressure sensor  32  is threaded into or otherwise coupled to a port communicating with the supply trails  24 . A filter (not shown) can be provided at the base of the sensor  32  to filter oil passing through the supply trail  24 . 
     Narrow worm trails  33  formed along the perimeter and other interior paths parallel to the trails  24 ,  26  and  27  receive elastomeric sealant (not shown) that is preferably molded in place. The sealant in the interior trails seals the seal plate  13  with the top plate  12  thereby closing the otherwise open side of the grooves or trails  24 ,  26  and  27 , converting these trails into independent closed hydraulic circuits. 
     The seal plate  13  (FIG. 7) and the gasket seal plate  21  (FIG. 9) have profiles that are substantially the same and that are slightly smaller than the peripheral sealant trails  33  on the top plate  12 . This geometry enables the sealant in the peripheral top plate trails  33  to seal on the surface of the engine block surrounding the valley between the cylinder banks. The seal plate  13  and gasket seal plate  21  also have patterns of coincident or aligned holes (or tabs in the case of the seal plate) that are substantially the same and are in alignment. For the most part, these holes (or tabs) provide for hydraulic fluid flow or serve functions for mounting of the solenoids  16  on the plate assembly  11 . More specifically, most of the holes (or tabs) in the seal and gasket seal plates  13 ,  21 , are in repeated patterns, each pattern being associated with a solenoid  16  and valve center or station  23 . A study of FIG. 3 shows that the solenoids  16  have two different orientations and, consequently, the pattern of oil flow holes or ports  36 ,  36   a ,  37 ,  37   a ,  38 ,  38   a ,  39  and  39   a , and solenoid mounting holes  41   a ,  42 ,  42   a  (or tabs  43 ) have the same two different orientations. The gasket seal plate  21  has elastomeric seals  44  molded in place in a known manner on both of its faces around and in the oil flow holes  36   a - 39   a . Holes or ports  36 ,  36   a ,  37  and  37   a  in the seal plate  13  and gasket seal plate  21  supply oil to and from a respective solenoid  16  and holes  39 ,  39   a , as discussed below, conduct control pressure to pin tower structures in the engine for disabling associated intake and exhaust valves. The holes  39 ,  39   a  lie under and communicate directly with respective control trails  26 . 
     The solenoids  16 , which are preferably identical, are generally conventional in construction. With particular reference to FIG. 11, the solenoids  16  are assemblies that include an injection molded plastic bobbin  46  on which is wound an electrical winding  47  connected to terminals  48  extending out of the bobbin. A steel sleeve  51  disposed on the bobbin  46  concentrates the magnetic field produced by the bobbin winding  47 . The solenoid assembly  16  also includes a magnetic pole plate  52  (FIG. 10) of suitable steel and a magnetic steel yoke  53 . The bobbin  46  is secured to the pole plate  52  with tabs integrally formed on the yoke. The tabs are assembled through holes  54  in the pole plate  52  and are plastically deformed to lock these elements in place. Small holes  56  in the pole plate  52  receive short bosses (not shown) molded in the bobbin for alignment purposes. An elastomeric O-ring  57 , concentric with the axis of the coil or winding  47 , forms a seal between the pole plate  52  and the bobbin  46 . An armature  58  is disposed in and coaxial with the bobbin  46 . The armature  58  includes a coaxial projecting pin  59  that is proportioned to extend into the center of a valve seat hole  61  in the pole plate  52 . The main body of the armature  58  can be hollow and the pin  59  can be assembled and permanently locked in position in the main body in a known manner. The windings  46  are protected by a suitable injection molded thermoplastic insulator  62 . 
     The solenoid assembly  16  of the bobbin  46 , armature  58 , yoke  53 , pole plate  52  and insulator  62  is assembled to the plate assembly  11  by slipping an edge of the pole plate in the throat of a right angle tab  43  that depends (in the working orientation) from the seal plate through the gasket seal plate  21 . A bolt is thereafter assembled through a hole  64  in the pole plate  52 , aligned holes  42   a ,  42  in the gasket seal plate  21  and seal plate  13 , respectively, and threaded into a blind hole in the top plate  12  to thereby hold the solenoid assembly  16  in place against the gasket seal plate as well as the plates  21 ,  13  and  12 , together. When the pole plate  52  is assembled against the gasket seal plate  21 , an inlet hole  66 , the valve seat hole  61 , and a slot  68  register with holes  36 ,  36   a ,  37 ,  37   a ,  38 ,  38   a  in the seal plate  13  and gasket seal plate  21 , respectively. 
     At each of the several valve centers or stations  23 , an integral boss  71  is cast on the top plate  12  to provide increased wall thickness or height for reception of a valve ball  72  and valve spring  73  and increased height of the exhaust worm trail  27  (FIG. 5 b ) compared to the height of the supply and control trails  24 ,  26 . 
     With reference to FIG. 12, an exhaust plug  74  is pressed fluid tight into an exhaust trail  27 . A cylindrical surface segment  75  cooperates with an opposed end surface  76  of the trail  27  to form a cylindrical pocket. A cylindrical ring-like exhaust valve seat  77  is pressed, fluid tight, into the pocket between the exhaust plug  74  and surface  76 . A cylindrical surface  78  on a top face (in the working orientation) of the exhaust plug  74  is a boundary for a passage for exhaust flow coming through the center of the exhaust seat  77 . 
     The spring  73  resiliently holds the valve ball  72  against a circular edge  81  of the pole plate hole  61  and the hole edge  81  serves as a valve seat for supply flow. The hole edge  81  can be slightly counter-sunk or otherwise formed to improve its sealing function. 
     The connector frame  17  extends lengthwise of the plate assembly  11  under the solenoids  16 . The connector frame  17 , injection molded of suitable plastic material, has individual electrical conductor strips insert molded on its upper face (in the working orientation) that are arranged to contact the terminals  48  of the solenoids  16 . One of the conductor strips can be common to one terminal of each of the solenoids  16 . The connector frame  17  has holes molded in it at appropriate locations to allow the terminals  48  to extend through it to assure contact with an associated conductor. One end of the conductor frame is arranged to mate with the multi-conductor connector  18  that extends through aligned holes  88 ,  88   a  and  88   b , in the top plate  12 , seal plate  13  and gasket seal plate  21 , respectively, and snaps into assembled position with suitable barbs. Conductors in the connector  18  individually join the conductors of the connector frame  17  to a mating connector (not shown) of a branch of a wiring harness of the engine. 
     The module  10  is installed on an engine by positioning it over the valley between the banks of cylinders and securing it in place with bolts assembled through peripheral holes  91  in the top plate  12 . Sealant in the trail  33  surrounding the supply port  22  seals around a mating port on the engine block that supplies pressurized engine lubrication oil to the module  10 . The gasketted holes  39   a  in the gasket seal plate  21  are positioned to overlie and seal on flat end faces of hollow pin towers rising from the central area of the engine valley. The towers carry oil between the module  10  and spring biased pins that are operable to connect or disconnect intake and exhaust valves to disable their associated piston cylinders. When oil in the towers is at a low pressure, the spring bias on the pins cause the pins to move to connect the intake and exhaust valves to their driving elements. When the pressure of the oil in the towers is elevated, the spring bias force on the pins is overcome and the pins are moved by the oil pressure to disconnect the intake and exhaust valves from their driving elements. It will be understood, thus, that when oil in the control trails  26  is pressurized, the intake and exhaust valves of the engine and the cylinders associated with them will be deactivated. 
     In operation of the engine, pressurized engine oil is delivered from a passage to the inlet or supply port  22 . This supply oil is regulated by the pressure relief valve  31  connected to the supply port by the trail  24  and is monitored by the sensor  32  communicating with this trail. 
     Small quantities of pressurized oil pass through a bleed orifice  93 , associated with each valve station  23 . The bleed orifice  93  has a relatively small minimum cross-sectional area (FIG. 5 a  and FIG.  6 ). By way of example, the bleed orifice  93  can be a semi-circular passage having a radius of 0.50 mm. Flow through the bleed orifice  93  reduces air bubbles in the respective control trails  26  and associated engine valley pin towers. This reduction in the presence of air improves the time response of the hydraulic circuitry. Transitional areas  94  between the bleed orifice  93  and associated control trail  26  in the form of half conical areas that expand laterally from the bleed orifice ensure that oil flow is distributed across the full width of the control trail to flush away air bubbles which might exist at the corners of the trails formed with the seal plate  13 . It will be seen that oil in the control trails  26  is maintained above the pressure in the exhaust trails  27  by the head (height) of the oil column that exists in the exhaust circuit beyond the valve station  23 . The bleed orifice  93  is situated to produce a continuous flow that sweeps across the pin towers below the holes  39 a and  39  associated with the control trail  26 . Moreover, the bleed orifice  93  is situated such that it produces a flow in a direction that assists evacuation of pressure in the pin towers and control trail  26  when quick response is most important when full engine power is demanded and the control trail is connected to the exhaust trail  27 . 
     When the engine is under load, the engine control module maintains all of the cylinders in operation. When the engine is under a light load, the engine control module can ordinarily deactivate two or four cylinders by electrically energizing two or four of the solenoids  16 . Generally, though not necessarily, cylinders are deactivated in pairs for smoothest operation. At each valve station  23 , before a solenoid  16  is actuated the valve spring  73  holds the ball valve  72  against the valve seat formed by the edge  81  of the pole plate hole  61 . The force of the spring  73  is sufficient to maintain the ball valve  72  closed on the seat  81  against the supply pressure existing in the space around the armature  58  by way of the arcuate holes  36 ,  36   a  and  66  in the seal plate, gasket seal plate and pole plate from the supply trail  24  with which these holes communicate. At this time, any shunted supply flow through the bleed orifices  93  and the control trails  26  passes through the exhaust valve seat  77 , over the exhaust plug surface  78  in the exhaust trail  27  and out of the exhaust holes  38 ,  38   a  and notch  68  in the seal plate, gasket seal plate and pole plate, respectively, and down into the valley of the engine block. 
     When the engine control module energizes a solenoid  16 , its armature  58  overcome the force of the spring  73 , opening the respective ball valve  72  off of the pole plate valve seat  81  and closes the ball valve against the exhaust seat  77 . The result is that supply pressure passing from the supply port  22  through the armature area of the solenoid  16  and out of the valve seat  81  is applied to the associated control trail  26 . Since the exhaust seat  77  is closed, full supply pressure is developed in the control trail  26  and, therefore, in the engine pin towers connected to the associated ports or holes  39 ,  39   a . As indicated above, supply pressure in the towers shifts pins to disengage associated intake and exhaust valve drive mechanism thereby deactivating the respective cylinders. 
     By disposing the valve seats  77  and  81  adjacent or in the planes of the plates  12 ,  13 , the module can be advantageously constructed economically and with a relatively low profile which can be important in engine and vehicle design. 
     FIGS. 13 through 15 illustrate a second embodiment of an electro-hydraulic module  101  of the invention. FIG. 13 shows an exploded isometric view of the module  101 . The module  101  includes a top plate  102 , seal plate  103 , valve body or plate  104 , pole plate  105 , solenoids  106  and connector frame  107 . The top plate  102  in a manner similar to that described above for the top plate  12  has grooves or trails  111 ,  112  and  113  for supply, control and exhaust functions, respectively. As indicated in FIG. 13 the electro-hydraulic module  101  is characterized by an arrangement wherein the solenoids  106  (and their associated valve elements discussed below) are grouped near the center of the plates  102 ,  103  and wherein the solenoids  106  share a common pole plate  105 . FIG. 15 is a diagrammatic representation of a typical solenoid  106  and associated valve section  114  in the valve body  104 . The solenoid  106  has an injection molded plastic bobbin  120  on which a coil  121  is wound. The bobbin  120  is sealed with the pole plate by an O-ring  122 . An armature  123  including a central pin  124  is responsive to the magnetic field of the coil  121  when the latter is electrically energized to displace a ball valve  126  of the valve section  114  against the force of a spring  127 . The solenoid includes a yoke or housing  131  having tabs received and locked in holes in the pole plate  105  to fix the solenoid  106  on the pole plate  105  in the general manner described above in connection with the yoke  53 . Suitable gaskets  132 ,  133  and  134  of paper or other known material are disposed between the pole plate  105  and valve body  104 , the valve body and the seal plate  103 , and the seal plate and the top plate  102 . 
     The valve section  114  associated with each solenoid  106  includes, besides the ball valve  126  and spring  127 , a control valve seat  136  formed at the edge of a hole  137  in the pole plate  105  through which the armature pin  124  operates and an exhaust valve seat  138  on an end of a tubular insert  139 . The insert  139  which supports the spring  127  is pressed in a bore  141  in the valve body  104 ; the position of the exhaust seat  138  relative to the control seat  136  can be precisely set by gauging the position of the insert  139  for improved valve performance. For each valve section  114 , the valve body  104  has supply, control and exhaust passages  142 ,  143  and  144 , respectively, that align with corresponding supply, control and exhaust trails  111 ,  112  and  113 , respectively. Operation of a valve section  114  is like that described in connection with the valves of the module  10 . 
     The solenoids  106  are individually connected to separate wires in a wiring harness (not shown) by the connector frame  107 . The connector frame  107  is an injection molded plastic body that has separate conductors that are engageable with the terminals  125  of the solenoids  106 . The conductors, which are preferably insert molded in the body of the connector frame  107  preferably have integral connector formations that can mate with conductors in a multiple pin or blade connector inserted through central holes  147 ,  148 ,  149  and  150  in the top plate, seal plate, valve body and pole plate  102 - 105 , respectively. The insert molded conductors and integral connectors in the connector frame can be stamped from flat metal stock such as beryllium copper. The connector frame  107 , besides electrically connecting the solenoids  106  to the engine control module, serves to prevent screws holding the pole plate  105  and valve body  104  to the plates  102 ,  103  from backing out of threaded blind holes in the top plate  102  and falling into the engine valley. The connector frame  107  is preferably held against the pole plate by screws (not shown). Holes or ports  151  in the seal plate  103  align with the top end faces of pin towers extending upwardly in the engine valley to the plane of the module  101  to connect the control trails  112  to such towers. 
     It will be understood that, with respect to the embodiment of FIGS. 1-12, the sealant molded in the trails  33  and the sealant around the holes on the gasket seal plate are relatively inexpensive compared to O-rings and can seal against planar surfaces without the need for lateral constraint such as a countersunk hole or other formation which would be required by an O-ring. It is contemplated that gaskets similar to those shown in the embodiment of FIGS. 13-15, which also seal against planar surfaces without lateral restraint, can be substituted in the embodiment of FIGS. 1-12 for the molded sealant and vise versa. It is also contemplated that the exhaust plug  74  and exhaust seat  77  can be integral. 
     While the invention has been shown and described with respect to particular embodiments thereof, this is for the purpose of illustration rather than limitation, and other variations and modifications of the specific embodiments herein shown and described will be apparent to those skilled in the art all within the intended spirit and scope of the invention. Accordingly, the patent is not to be limited in scope and effect to the specific embodiments herein shown and described nor in any other way that is inconsistent with the extent to which the progress in the art has been advanced by the invention.