Directly actuated engine valve

Abstract

An engine valve assembly includes an engine valve ( 12 ) connected to an electric motor ( 30. ) The electric motor may be a linear electric motor ( 34 ) which includes “rare earth” magnets to infinitely move the engine valve ( 12 ) between an open and closed position. Usage of “rare earth” magnets assures that the linear electric motor ( 34 ) generates enough force to properly and timely operate the engine valve ( 12. ) The electric motor ( 30 ) may alternatively drive a threaded portion ( 42 ) of the valve stem ( 18. ) Operation of the electric motor ( 30 ) threads the threaded valve stem ( 18 ) relative to a threaded support ( 40 ) to drive the engine valve ( 12 ′) between an open and a closed position.

What is claimed is:  
     
         1 . An engine valve assembly for an engine cylinder comprising: 
 an engine valve having a stem portion and a head portion, said valve stem defining an axis and; and    an electric motor mounted to said valve stem to drive said engine valve along said axis to move said engine valve between an open and a closed position.    
     
     
         2 . The engine valve assembly as recited in  claim 1 , wherein said electric motor includes a rare earth magnet.  
     
     
         3 . The engine valve assembly as recited in  claim 1 , wherein said electric motor is a linear electric motor to slide said vale along said axis.  
     
     
         4 . The engine valve assembly as recited in  claim 3 , wherein said linear electric motor includes a linear stator and a slidable rotor which is drivable relative to said linear stator, and a force multiplier between said slidable rotor and said valve stem.  
     
     
         5 . The engine valve assembly as recited in  claim 4 , wherein said force multiplier includes a rack and pinion gear arrangement.  
     
     
         6 . The engine valve assembly as recited in  claim 1 , wherein said valve stem includes a threaded stem portion.  
     
     
         7 . The engine valve assembly as recited in  claim 6 , wherein said threaded stem portion is screwed into a threaded support.  
     
     
         8 . The engine valve assembly as recited in  claim 7 , wherein said electric motor rotates said valve stem to screw said engine valve relative to said support and move said engine valve between said open position and said closed position.  
     
     
         9 . The engine valve assembly as recited in  claim 1 , wherein said valve stem includes a threaded stem portion and a rotor of said electric motor includes a corresponding threaded portion.  
     
     
         10 . An engine valve assembly for an engine cylinder comprising: 
 an engine valve having a threaded stem portion and a head portion, said threaded valve stem portion defining an axis;    a threaded support to receive said threaded valve stem portion; and    an electric motor operably connected to said threaded valve stem, said electric motor operable to rotate said engine valve relative to said threaded support to drive said engine valve along said axis between an open and a closed position.    
     
     
         11 . The engine valve assembly as recited in  claim 10 , wherein said electric motor includes a rare earth magnet.  
     
     
         12 . The engine valve assembly as recited in  claim 10 , wherein said electric motor is mounted substantially perpendicular to said axis.  
     
     
         13 . The engine valve assembly as recited in  claim 10 , wherein said threaded support includes a rotor rotatably mounted to a fixed stator.  
     
     
         14 . The engine valve assembly as recited in  claim 13 , further comprising a guide which prevents rotation of said engine valve.