Abstract:
A valve deactivator is provided that is capable of being activated and deactivated by a pulse energy input. The valve deactivator includes an input member and an output member which are movable relative to one another in the deactivated mode and which are engaged for simultaneous movement in an activated mode. A coil and armature, or other pulse energy input means, are provided to engage and disengage a locking system to activate and deactivate the valve actuator.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional application Ser. No. 60/194,558 filed Apr. 3, 2000. The disclosure of which is incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to an electromagnetically or hydraulic actuated pulse driven two position ratchet mechanism for valve deactivation in push rod and overhead camshaft internal combustion engines. This pulse system can be adapted to a push rod configuration, or at a rocker location of an overhead camshaft valve drive. For improved fuel economy strategic cylinders would be deactivated by inducing a break in the valve drive linkage using a time sensitive switching device activated by an energy conserving pulse versus the continuous power on versions.  
         DESCRIPTION OF RELATED ART  
         [0003]    Traditionally, valve deactivation devices are complex designs employing a remote located solenoid using a drive linkage which is held to the on position by a continuous energy draw to a solenoid coil, or continuous hydraulic pressure. Valve deactivation systems (VDS) date back to the early 1970s. The first successful system was a latchable fulcrum for pushrod rocker arms on Cadillac V8 engines in 1981. Further present day valve deactivation system examples are those of INA Motor Enelment uses a 3 lobe camshaft, dual bucket configuration for overhead camshaft engines wherein a high lift/no lift event is achieved by driving the outer bucket with the higher profile peripheral camshaft lobes for high lift, and driving the central camshaft lobe and bucket for no lift. This system employs a sliding hydraulic operating pin, which switches to connect outer bucket to inner bucket to generate, timed lift event. Another INA design uses a two-piece valve rocker where the primary rocker section driven by the camshaft is connected or disconnected to a secondary rocker activating the valve by a sliding pin. It should be appreciated that all valve deactivation systems need a power supply, and a driven switching engagement element such as a pin, which is very critical to operation. The reason for this preciseness is you only have the rest time, or camshaft base circle time when the valvetrain rockers and pushrods are not in motion for insertion of a locking pin or switching element. It also should be noted that the switching sequence time decreases, as engine RPM becomes higher. Therefore, it is an advantage to use a time compatible geometry for switching element.  
         SUMMARY OF THE INVENTION  
         [0004]    The present invention provides a compact concentrically located solenoid drawing a short energy pulse to drive a ratcheted geometric switching key to join or detach adjacent moving valvetrain elements. A significant feature of this design is its fast, direct solenoid reaction time, and specialized rotative locking key which moves at the same velocity as the retaining member it is locked to for valve deactivation.  
           [0005]    It is therefore a primary object of this invention to provide a specialized locking key which, unlike a pin or latch, when driven will provide superior performance within camshaft base circle diameter time window.  
           [0006]    It is another object of this invention to locate the driving armature close to the locking key to lower the mass of the connecting members needed to switch the locking key for faster operation.  
           [0007]    It is yet another object of this invention to design a solenoid concentrically to delete remote connecting members, simplify design, and lower drive members for fast reaction time.  
           [0008]    It is still another object of this invention to drive the locking key to an engaged position with one energy pulse.  
           [0009]    It is yet another object of this invention to combine the solenoid locking system and tappet in one compact assembly for push rod application.  
           [0010]    It is a further object of this invention to be adaptable for location high in a cylinder head for easy service.  
           [0011]    It is still a further object of this invention to adapt the solenoid and locking key assembly to a primary and secondary rocker for valve deactivation on overhead camshaft engines.  
           [0012]    To achieve the foregoing objects, the present invention provides an electromagnetically pulse driven two-position specialized ratchet mechanism for valve deactivation. One advantage of the present invention is a low mass special key for faster response is used operating in camshaft base circle diameter time window.  
           [0013]    Another advantage of the present invention is that the driving armature can be located very close to the switching key for fast activation.  
           [0014]    A further advantage of the present invention is that the solenoid is designed concentrically creating a compact unit deleting the need for remote connecting elements.  
           [0015]    A further advantage of the present invention is that the locking key is driven to the engaged position by one pulse, thus conserving the energy needed to activate versus continuously applied versions.  
           [0016]    Still another advantage of the present invention is that the activation unit can be adapted to both push rod and overhead camshaft engines.  
           [0017]    Yet still another advantage of the present invention is that the electro solenoid system does not contend with the low RPM oil pressure, and oil pump energy draw of hydraulic systems.  
           [0018]    Another advantage of the present invention is that the locking key has more latitude in build tolerancing.  
           [0019]    Other features and advantages of the present invention will be readily appreciated, as the same becomes better understood after reading the subsequent description taken in conjunction with the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0021]    [0021]FIG. 1 is a cross section of a pulse drive valve deactivator, according to the principles of the present invention;  
         [0022]    [0022]FIG. 2 is a cross section of the pulse drive valve deactivator showing the solenoid armature in a locking mode;  
         [0023]    [0023]FIG. 3 is a cross section of the pulse drive valve deactivator showing the energy flow in the locked mode;  
         [0024]    [0024]FIG. 4 is a cross section of the pulse drive deactivator showing the tappet in a high lift position working in the unlocked mode;  
         [0025]    [0025]FIG. 5 is a cut-away perspective view illustrating the locking key in unlocked mode;  
         [0026]    [0026]FIG. 6 is a cut-away perspective view illustrating the locking key in locked mode; and  
         [0027]    [0027]FIG. 7 is a side view of the pulse drive valve deactivator adapted to be used with a roller finger follower type overhead camshaft system. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0029]    With reference to FIG. 1, the pulse drive valve deactivator  1  of the present invention is shown as a compact unit mounting over tappet  2 . The pulse drive valve deactivator can be utilized for present production engines or integrated into a tappet for new engine applications. The valve deactivator  1  is illustrated to be mounted in position by fastener  3  abutting the key drive retainer  4  adjacent the tappet  2  at surface  5 . As the camshaft (not shown) rotates, tappet  2  moves in the direction of arrow “ 6 ” driving the key drive retainer  4  which compresses lost motion spring  7  against surface  8  of push rod retaining socket  9 .  
         [0030]    Push rod retaining socket  9  is held immobile by push rod  13 . The valve spring (not shown) acting upon the push rod  13  has a higher spring constant than the spring constant of lost motion spring  7 . As key drive retainer  4  moves in an unlocked mode, channel  10  slides along lugs  11  of stationary positioned locking key  12 . Locking key  12  is loaded against key driver  14  by spring  15  and pivot ball  15 A which are received in a central bore  9 A of the push rod retaining socket  9 . Key driver  14  is joined to armature  16  at opening  17  which receives a head portion  14 A of the key driver  14 . Armature  16  is held against a stop  18  extending from an internal wall  19 A of solenoid frame  19  by a wave spring  20 .  
         [0031]    Key drive retainer  4  employs fingered projections  21  working through windows  22  provided in the armature  16  for connection to the tappet  2 . It should be appreciated that in an unlocked mode only tappet  2  and key drive retainer  4  compressing lost motion spring  7  against surface  8  of push rod retaining socket  9  are moving as the camshaft (not shown) turns. Tappet  2  needs a diameter lift distance “ 23 ” (best shown in FIG. 1) to work in. Referring to FIG. 2, push rod  13  is activated during the time cycle at the beginning of the compression stroke, and the end of the power stroke when the valves are closed, and the valvetrain is at rest. During this period, coil  24  is energized from a power supply creating a magnetic field attracting the armature  16  toward the core  25  at surface  26 . Movement of the armature  16  drives the key driver  14 , thus propelling the locking key  12  along the channel  10  and thereby compressing spring  15  (shown compressed in FIG. 2). As the locking key  12  is propelled toward the surface  27  of push rod retaining socket  9 , locking key  12  is joined to key drive retainer  4  at the connecting juncture position  28 . The locking key  12  drives the push rod retaining socket  9  driving the push rod  13  activating the valve (not shown). It should be noted that when push rod  13  is driven in the direction of arrow “ 6 ,” the locking key  12  is compressed between surface  27  and connecting juncture  28  holding that locked position. When the valve spring thrusts the rocker (not shown) and push rod  13  in the direction of arrow “ 29 ,” the inertia of the locking key  12  and spring  15  are working in conjunction to keep the locking key  12  at a connection juncture  28  until the camshaft base circle time zone is reached wherein only spring  15  keeps locking key  12  seated.  
         [0032]    During the camshaft base circle time period the solenoid is energized driving the locking key  12  to compress spring  15  and index the locking key  12  to the unlocked mode.  
         [0033]    It should be appreciated that during this event, the locking key  12  moves rotatively at the same velocity as key drive retainer  4 .  
         [0034]    Referring to FIG. 3, the pulse drive valve deactivator  1  is shown functioning in a locked mode driving push rod  13 . Wave spring  20  returns the armature  16  to a rest position against stop  18  of the solenoid frame  19 . Tappet  2  is shown in a high lift position driving the key drive retainer  4  which is joined to the locking key  12  at connecting juncture  28  thereby activating push rod retaining socket  9 . As the push rod retaining socket  9  is activated, push rod  13  is moved. (Energy flow is illustrated by arrow “ 39 .”) It should be appreciated that during the locked mode, the lost motion spring  7  is not compressed and the key drive retainer  4  slides along the key driver  14  along channel  10 . Referring to FIG. 4, the pulse drive valve deactivator  1  is shown functioning in an unlocked mode with tappet  2  in a high lift position driving the key drive retainer  4  and compressing lost motion spring  7 . It should be noted that the only parts in motion are the tappet  2  and key drive retainer  4  moving along fixed locking key  12  and key driver  14  at channel  10 .  
         [0035]    [0035]FIG. 5 provides a detailed illustration of the locking event. Locking key  12  is shown in an unloaded mode wherein key drive retainer  4  slides along locking key  12  along grooves  30 . When the system is to be locked, the armature  16  moves the driver  14  in an upward direction which drives the locking key  12  along grooves  30 . As spring  15  is compressed, torsional energy is stored promoting the locking key  12  to rotate because of the interface of slope  31  and space  32 . This misalignment exists until locking key  12  is high enough wherein point  33  of locking key  12  is even with point “ 34 ” of key retainer  4 . At this time, the locking key  12  is free of groove  30  and will start to index in the direction of arrow “ 35 ” because of the spring load, slope  31 , and filling misalignment space  32  will excite locking key  12  to rotate to the locked position as shown in FIG. 6. It should be noted that the energy pulse applied by the armature  16  could also be supplied by other pulse energy activating devices including hydraulic, pneumatic, or mechanical actuator systems that can replace or be substituted for the armature and coil system. It is important to note that because of the torsional energy stored by spring  15 , it is only an energy pulse that is required to engage the locking key.  
         [0036]    Referring to FIG. 6, the locking event is a two-stage event because the timed solenoid energy pulse drives the locking key  12  out of groove  30  to begin rotation but energized spring  15  completes the locking/seating event, as the solenoid charge decays, forcing the locking key  12  to continue to rotate as point “ 39 ” of locking key  12  aligns with point “ 36 ” of the key drive retainer  4  completing rotation of the locking key  12  to a locked seated position as shown at position  37  and  38 . It should be appreciated that when in the locked mode, spring  15  always loads the locking key  12  to the locked position  37  and  38  during camshaft base circle time duration.  
         [0037]    To unlock the system, armature  16  strokes in the direction of arrow “ 6 ” driving the key driver  14  into the locking key  12  and compressing spring  15 . At this time, misalignment at slope  31  and space  32  lifts and rotates the locking key  12  in the direction of arrow “ 35 ” over positions  37  and  38  propelling the locking key  12  down grooves  30  to the unlocked mode as shown in FIG. 5.  
         [0038]    [0038]FIG. 7 is a side view showing a roller finger follower (or end pivot rocker arm), pulse drive deactivator combination lash adjuster adapted to an overhead camshaft engine. The pulse drive deactivator  1  (shown in phantom) positions a lash adjuster  40  at a location  41  for a deactivated mode where rocker arm  42  rotates and compresses lost motion spring element  43 . When valve  44  is to be activated, the pulse drive deactivator  1  cycles an energy pulse activating the locking key  12  moving the lash adjuster  40  to the valve drive location  45  wherein rocker arm  42  rotates to migrate valve  44  compressing valve spring  46  (shown in phantom).  
         [0039]    The present invention has been described by text and images conveying a combination of conceptual ideas based on primary designs. It is to be understood that many evolutionary modifications and variations of the present invention are possible in light of the above description.