Abstract:
A lever electromechanical valve actuator assembly and arrangement of electromechanical valve actuators that creates a compact actuator assembly to increase ease of serviceability, provide space for engine components and eliminate interference between the actuators and components in the vehicle engine compartment.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/510,988, filed Oct. 14, 2003, the entire disclosure of this application being considered part of the disclosure of this application and hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to electromechanical valves actuators and, more particularly, to compact electromechanical valve actuator assemblies and the arrangement of electromechanical valve actuators on an engine.  
         [0003]     As engine technology advances and manufacturers strive to increase engine power, improve fuel economy, decrease emissions, and provide more control over engines, manufacturers are developing electromechanical valve actuators (also known as electromagnetic valve actuators or EMVA) to replace cam shafts for opening and closing engine valves. Electromechanical valve actuators allow selective opening and closing of the valves in response to various engine conditions.  
         [0004]     Electromechanical valve actuators generally include two electromagnets and a spring loaded armature plate disposed between the electromagnets. The armature plate is movable between the electromagnets as the power coils are selectively energized to create a magnetic force to attract the armature plate to the energized electromagnet. The surface of the electromagnets to which the armature is attracted is generally referred to as a pole face and the armature is operationally coupled to the valve so that as the armature moves between pole faces in a pole-face-to-pole-face operation, the valve is opened and closed.  
         [0005]     Electromechanical valve actuators are generally formed as linear electromechanical valve actuators or lever electromechanical valve actuators. One problem with linear electromechanical valve actuators is that each electromechanical valve actuator operationally coupled to the associated valve includes a relatively large set of electromagnets for opening and closing the valves ( FIG. 1 ). The size of the electromagnets makes it difficult to position all of the linear electromechanical valve actuators over a particular cylinder, especially for engines that have four or more valves per cylinder. The size of linear electromechanical valve actuators may also limit the ease of serviceability of the engine, such as by restricting the space available for changing the spark plug. Another problem with linear electromechanical valve actuators is that linear electromechanical valve actuators generally have a substantial height extending from the cylinder head of an engine. The height of the linear electromechanical valve actuators makes them difficult to package engines in today&#39;s compact and full engine compartments. For example, linear electromechanical valve actuators may interfere with other engine parts, other components or accessories located in the engine compartment, and even the vehicle body structure, such as, the hood. Yet another problem with linear electromechanical valve actuators is that they generally draw a substantial amount of power from the vehicle electrical system, as compared with lever electromechanical valve actuators, thereby putting additional demand on the alternator in today&#39;s power hungry vehicles.  
         [0006]     In view of the drawbacks associated with linear electromechanical valve actuators, many manufacturers have recently turned to lever electromechanical valve actuators, which due to their mechanical and magnetic properties have substantial power savings over linear electromechanical valve actuators. Lever electromechanical valve actuators also generally do not protrude as far from the cylinder head as linear electromechanical valve actuators. However, a major problem with lever electromechanical valve actuators is still the package size required on the cylinder head. Due to the set locations of valves by engine designers, designs for actuator assemblies on the engine have been traditionally limited. Most lever electromechanical valve actuators packaged on the cylinder head are arranged longitudinally in line with the cylinder head as a group, as shown in  FIG. 2 , with each actuator group being arranged laterally across the cylinder head. As shown in  FIG. 2 , the lever electromechanical valve actuators on an engine having four valves  20  per cylinder  16  requires significantly more space laterally across a cylinder head than cam shafts, thereby presenting packaging concerns in engine compartments where space is limited. Also, the arrangement of lever electromechanical valve actuators shown in  FIG. 2  raises additional serviceability concerns, especially for the ease of servicing and replacing the spark plug and in some arrangements, the fuel injector. In the embodiment illustrated in  FIG. 2 , at least two of the actuators are completely within the perimeter of the cylinder walls extended toward the actuators, making it difficult to change the spark plug as well as service the actuators. Therefore, there is a need for additional electromechanical valve actuator arrangements that minimize package space, provide ease of serviceability, and provide room wiring assemblies and control modules communicating with the individual actuators.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention relates to electromechanical valve actuators and, more particularly, to compact electromechanical valve actuator assemblies and the arrangement of electromechanical valve actuators on an engine.  
         [0008]     Careful arrangement of electromechanical valve actuators to create a compact assembly increases ease of serviceability, provides space for access to various engine components such as the spark plug, provides additional package space for wiring harnesses and control modules of electromechanical valve actuators, and eliminates potential interference between the actuators and components in the vehicle engine compartment or the vehicle body.  
         [0009]     In a first embodiment, the lever electromechanical valve actuator assembly includes a first actuator having a first pivot end and a first lever end, and a second actuator adjacent to said first actuator, said second actuator including a second pivot end and a second lever end. The first and second actuators are oriented in the same direction and arranged such that the first lever end is in closer proximity to the second pivot end than the second lever end. In a second embodiment, a lever electromechanical valve actuator assembly includes a first actuator having a first pivot end and a first lever end and a second actuator including a second pivot end and a second lever end wherein the second actuator is approximately a mirror image of the first actuator and oriented opposing the first actuator. In a third embodiment, the lever electromechanical valve actuator assembly is located on at least two adjacent cylinders, with at least two actuators on each cylinder. The two actuators on a first cylinder face the same direction, while the two actuators on the adjacent cylinder each face a direction substantially opposite the first direction.  
         [0010]     Further scope of applicability of the present invention will become apparent from the following detailed description, claims, and drawings. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The present invention will become more fully understood from the detailed description given here below, the appended claims, and the accompanying drawings in which:  
         [0012]      FIG. 1  is a prior art top plan view of the placement of linear electromechanical valve actuators over cylinders;  
         [0013]      FIG. 2  is a prior art top plan view of the lever electromechanical valve actuators over cylinders;  
         [0014]      FIG. 3  is a top plan view of the lever electromechanical valve actuator assembly on a cylinder head;  
         [0015]      FIG. 4  is a cross-sectional view along lines  4 - 4  in  FIG. 3 ;  
         [0016]      FIG. 5  is a top plan view of a first alternative lever electromechanical valve actuator assembly arrangement on a cylinder head;  
         [0017]      FIG. 6  is a top plan view of a second alternative lever electromechanical valve actuator assembly arrangement on a cylinder head;  
         [0018]      FIG. 7  is a top plan view of a third alternative lever electromechanical valve actuator assembly arrangement on a cylinder head;  
         [0019]      FIG. 8  is a top plan view of the lever electromechanical valve actuator assembly arrangement on a cylinder head having only intake valve actuators;  
         [0020]      FIG. 9  is a top plan view of the first alternative lever electromechanical valve actuator assembly arrangement on a cylinder head with only intake actuators;  
         [0021]      FIG. 10  is a top plan view of the second alternative lever electromechanical valve actuator assembly arrangement on a cylinder head with intake actuators only; and  
         [0022]      FIG. 11  is a top plan view of the lever electromechanical valve actuator assembly with the exhaust and intake actuators shifted laterally apart on the cylinder head. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]     A lever electromechanical valve actuator assembly  10  is illustrated in  FIG. 3 , mounted on a cylinder head  80  of an internal combustion engine  12  and at least partially over the associated cylinder  16 . Each actuator  2 ,  4  of the lever electromechanical valve actuator assembly  10  is connected to a valve  20 , such as an intake or exhaust valve, to open and close the valve  20  as desired. The electromechanical valve actuator assembly  10 , as illustrated in  FIG. 3 , and as illustrated in the alternative embodiments shown in  FIGS. 5-11 , provides a more compact arrangement while allowing greater serviceability and easier assembly.  
         [0024]     The electromechanical valve actuator assembly  10  generally includes both intake actuators  2  and exhaust actuators  4  as illustrated in  FIGS. 3 and 4 - 7 . Of course, the actuator assembly  10  may include only intake actuators  2  as illustrated in  FIGS. 8-10 , only exhaust actuators (not shown), or a combination of the illustrated and claimed embodiments varying by cylinder or by intake or exhaust sides. For example, one actuator assembly may be suited for the intake side while another may be suited for the exhaust side, or different actuator assemblies may be used for different cylinders depending on engine configuration and packaging needs. The actuators  2 ,  4  each generally include an armature assembly  30  having an armature plate  32 , an electromagnet assembly  70  having electromagnets  72 ,  74 , a connecting rod  90  and a spring assembly  60 . The armature plate  32  is alternatively attracted to the electromagnets  72 ,  74  thereby applying force to the spring assembly  60  and valve  20  through the connecting rod  90  to open and close the valve  20 . While the actuators  2 ,  4  are illustrated as having a connecting rod  90  connected to the spring assembly  60 , any lever electromechanical valve actuator configuration, shape, or assembly may be substituted for the illustrated electromechanical valve actuators in  FIG. 4 , as the present invention is primarily directed to the arrangement of the electromechanical valve actuators  2 ,  4  relative to each other, relative to the cylinder head  80  and relative to the cylinders.  
         [0025]     The valve  20  is similar to traditional valves and generally includes a valve head  22  with a valve stem  24  extending therefrom. The valve  20  has an opened and closed position and is illustrated in  FIG. 4  in the closed position. In the closed position, the valve head  22  seals a valve port  14  to the corresponding cylinder  16 . The valve port  14  may be an exhaust port or intake port and the actuator  2 ,  4  located thereon is either the intake actuator  2  for an intake port or an exhaust actuator  4  for an exhaust port.  
         [0026]     The electromagnet assembly  70  controls the movement of the armature assembly and thereby the movement of the valve  20 . The electromagnets  72 ,  74  are generally secured to c-blocks  8 ,  9  which are in turn secured to the cylinder head  80 .  
         [0027]     The armature assembly  30  includes the armature plate  32  and the connecting rod  90 . The armature plate  32  pivots about a pivot axis  44  near a pivot end  49  of the armature plate  32  to open and close the valve  20 . The connecting rod  90  is coupled to or driven by the armature plate  32 . The lever end  48  of the armature plate  32  is opposite the pivot end  49 . While any electromechanical valve actuator may be used in the present invention to create the lever electromechanical valve actuator assembly  10 , the electromechanical valve actuators  2 ,  4  described above and illustrated in  FIG. 4  provide further space savings and further facilitate the arrangement of the electromechanical valve actuators.  
         [0028]     To facilitate the description of the electromechanical valve actuator assembly  10  and the specific arrangement of the actuators  2 ,  4  relative to each other, the geometry and directional arrangement such as longitudinal and lateral extents of the cylinder head  80 , the cylinder  16 , and the actuators  2 ,  4  must first be described. The internal combustion engine  12  includes a desired number of cylinders  16 . The cylinders  16  may be arranged in any shape or configuration possible for the operation of an internal combustion, such as an in-line four cylinder engine or a V-6 engine. The cylinders  16  each include a cylinder axis  18  in the center along which the piston  15  travels. Cylinders  16  also include an outer perimeter wall  17 . In this application and in the claims, when the perimeter is referred to as being extended toward the actuators  2 ,  4  or the extended perimeter, that description generally refers to not the actual extent of the perimeter  17  defined by the cylinder walls but a theoretical or virtual extension of the perimeter of the cylinder walls, beyond where the cylinder wall perimeter  17  actually stops when it meets the cylinder head  80 , toward the actuators  2 ,  4 . The cylinders  16  may further be described as being arranged along a cylinder longitudinal extent  19  which is generally along a longitudinal extent of the engine along a line drawn through the axes  18  of the cylinder  16 . The cylinder head  80  also includes a longitudinal extent  86  and defines a spark plug hole  88 . The cylinder head  80  is generally banked as shown in  FIG. 4 .  
         [0029]     The actuators  2 ,  4  generally include a longitudinal actuator extent  52  which is generally aligned with the pivot axis  44  and a lateral actuator extent  54  which is somewhat perpendicular to the pivot axis  44 . The actuators  2 ,  4  may also include a longitudinal actuator center  58  which is approximately the center of the longitudinal actuator extent  52 .  
         [0030]     In the primary embodiment, illustrated in  FIG. 3 , the lever electromechanical valve actuator assembly  10  is arranged so that intake actuators  2  are arranged laterally to the cylinder head  80 . More specifically, the longitudinal actuator extent  52  is arranged approximately perpendicular to the cylinder head longitudinal extent  86 . Therefore, as illustrated in  FIG. 3 , the actuators  2 ,  4  are arranged on the cylinder head  80  in a lateral configuration wherein the intake actuators  2  are approximately aligned laterally along the cylinder longitudinal extent  86  and the exhaust actuators  4  are also approximately aligned laterally along the cylinder longitudinal extent  86 . In this arrangement, the pivot end  49  of one actuator is arranged in closer proximity to the lever end  48  of the adjacent actuator over the same cylinder  16  than the pivot end  49  of the adjacent actuator. The arrangement of the pivot end  49  being in close proximity to the lever end  48  of the adjacent actuator arranges the actuators so that the actuators are oriented in the same direction and that the pivot end  49  of one actuator is closer to the lever end  48  of the adjacent actuator than the pivot end  49  of adjacent actuator. Further, as illustrated in  FIGS. 3 and 8 , the intake actuators  2  all face the same direction and if included, as shown in  FIG. 3 , the exhaust actuators also face the same direction. Of course, the intake actuators  2  may all face the same direction while the exhaust actuators  4  all face the same direction, but opposite the direction of the intake actuators  2  (not shown). As further illustrated in  FIG. 3 , the pivot axis  44  of the intake actuators  2  are substantially parallel and the pivot axis  44  of the exhaust actuators  4  are also parallel although not necessarily parallel to the intake actuators  2 . As illustrated in  FIGS. 3 and 4 , the pivot axes  44  of the intake actuators  2  and the exhaust actuators  4  are generally angled relative to each other due to the angled arrangement of the valves  20  and the banking of the cylinder head  80 . Therefore, even though the intake actuators  2  may be aligned along the cylinder longitudinal extent  86  with an exhaust actuators  4  such that the pivot axes  44  of an intake actuator  2  is aligned with a pivot axis  44  of an exhaust actuator  4 , the pivot axes  44  are generally angled relative to each other.  
         [0031]     As further illustrated in  FIGS. 3 and 8 , the connecting rod  90  which is coupled to the valve  20  is connected to approximately the center of the longitudinal actuator extent  52 , or along the longitudinal actuator center  58 . However, as illustrated in  FIG. 11 , the connecting rod  90  may be coupled to a position on the actuators  2 ,  4  which is offset from the longitudinal actuator center  58 . This offset configuration may allow greater serviceability of the engine and easier access to the spark plug hole  88  defined by the cylinder head  80 . Comparing  FIGS. 3 and 11 , the offset configuration in  FIG. 11  shifts the actuators  2 ,  4  laterally away from each other so that the intake actuators  2  are spaced further from the exhaust actuators in  FIG. 11  than in  FIG. 3 .  
         [0032]     In the illustrated embodiment, the actuator assembly  10  is arranged over the cylinders  16 . As shown in  FIGS. 3, 8 , and  11 , if the cylinder outer perimeter  17  is extended toward the actuators  2 ,  4 , each of the lever electromechanical valve actuators  2 ,  4  is located at least partially outside the extended perimeter. Further, as illustrated  FIGS. 3, 8 , and  11 , the actuators  2 ,  4  are shifted along the cylinder longitudinal extent  19  generally so that the cylinder axis  18  is not centered between the intake actuators  2  on a particular cylinder  16 . Therefore, the actuators  2 ,  4  arranged over a particular cylinder  16  are generally shifted laterally away from the cylinder axis and longitudinally along the cylinder axis  18  to one side of the cylinders  16 .  
         [0033]     While the spark plug hole  88  in the cylinder head  80  may be centered between the actuators  2 ,  4  both laterally and longitudinally or centered between one set of actuators  2 ,  4  such as the intake actuators  2  longitudinally, the actuators  2 ,  4  are generally shifted along the cylinder longitudinal extents  86  so that the spark plug is not longitudinally centered between the actuators  2 ,  4 . As illustrated in  FIGS. 3, 8 , and  11 , the spark plug hole  88  is approximately centered above the cylinder axis  18  for efficient engine operation.  
         [0034]     In the second embodiment illustrated in  FIGS. 5 and 9 , the actuator assembly  10  is also arranged such that the pivot axes  44  are parallel. More specifically, in the embodiment illustrated in  FIG. 5 , the intake actuators over a particular cylinder  16  are arranged such that they are a mirror image of each other with one actuator opposing the adjacent actuator. Further, the actuators  2 ,  4  are offset relative to the adjacent actuator  2 ,  4  on the same cylinder  16  along their longitudinal actuator extent. Although the valve  20  and connecting rod  90  are illustrated as being approximately centered along the longitudinal actuator extent  52 , the valve coupled to the actuators  2 ,  4  may be offset from the longitudinal actuator center  58 . Therefore, the adjacent actuators  2 ,  4  over a particular cylinder  16  are arranged such that the lever ends  48  are closer together than the lever end  48  of a particular actuator  2 ,  4  is to its pivot end  49 . As illustrated in  FIG. 5 , the intake actuators over a particular cylinder  16  are offset relative to each other. Further, the exhaust actuators  4  in the illustrated embodiment are offset approximately the same amount so that one pair of intake and exhaust actuators  2 ,  4  are laterally aligned along the cylinder longitudinal extent  86  while the other pair are also aligned along the cylinder longitudinal extent  86 . Further, in this embodiment each one of the actuators  2 ,  4  is at least partially located outside the extended outer perimeter  17  of the cylinder  16 . With the perimeter extended toward the actuators  2 ,  4 , the area within the extended perimeter  17  is less than half filled by the actuators  2 ,  4  providing substantial room on the cylinder head  80  between the actuators  2 ,  4  for serviceability.  
         [0035]     The embodiment illustrated in  FIGS. 6 and 10  further provides serviceability especially by freeing up area around the spark plug hole  88  on the cylinder head  80  by creating a spark plug access area  106 . The arrangement illustrated in  FIG. 6  is similar to the arrangement in  FIG. 5  in that each of the adjacent actuators is a mirror image of the other actuator. Therefore, in the embodiment shown in  FIG. 6 , the adjacent actuator associated with a particular cylinder  16  and on the intake or exhaust sides are oriented opposing each other.  
         [0036]     In the embodiment illustrated in  FIG. 7 , while all of the actuators face the same direction over a particular cylinder, the actuators  2 ,  4  adjacent to each other and slightly overlapping are on adjacent cylinders  16  so that the actuator  2 ,  4  over one cylinder overlaps the actuator  2 ,  4  over the adjacent cylinder in a manner such that two actuators oppose each other. Furthermore, in the embodiment shown in  FIGS. 6 and 7 , at least one actuator is within two of the extended outer perimeters. In each of the embodiments shown in  FIGS. 6 and 7 , the actuators may also be coupled approximately along the center  58  of the longitudinal actuator extent  52 . In the embodiment shown in  FIG. 11 , a control system, including a control module also may be situated at one end of the cylinder head  80  such that the control system  108  is at least partially situated over one of the extended cylinder perimeters.  
         [0037]     The foregoing discussion discloses and describes an exemplary embodiment of the present invention. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims that various changes, modifications and variations can be made therein without departing from the true spirit and fair scope of the invention as defined by the following claims.