Spring-less valve train for internal combustion engine

Abstract

A rocker arm ( 210 ) for use in a reciprocating, internal combustion engine includes a tip ( 235 ) and a seat ( 240 ). The tip and seat are urged to move by cams ( 220, 225 ) on a shaft ( 230 ). As the shaft rotates, the cams alternately apply force to the tip and the seat, causing the rocker arm to rotate about a pivot shaft ( 215 ). A valve ( 100 ) and valve stem ( 110 ′) are attached to the rocker arm. The valve is urged to open and close by motion of the rocker arm. Thus the valve is opened and closed through the use of positive camming and reciprocating forces only. No conventional valve spring is required to close the valve. Thus valve floating at high engine speeds is prevented and engine performance is improved.

1 . An internal combustion engine having a rotatable camshaft, at least one cylinder having at least one valve coupled to said camshaft and arranged to open and close a port in said cylinder, an improvement comprising coupling means for coupling said valve to said camshaft such that rotation of said camshaft alternately (a) cams said valve to an open position that opens said port, and (b) cams said valve to an closed position that closes said port, whereby strong valve springs do not have to be compressed during engine operation, resulting in improved engine efficiency through reduced fuel consumption, a lighter engine, lower engine wear, less heat, and improved engine performance. 
   
   
       2 . The internal combustion engine of  claim 1  wherein said coupling means comprises at least one rocker arm that follows said camshaft and seesaws in response to rotation of said camshaft and thereby forces said valve between said open and closed positions in response to the seesaw movement of said rocker arm. 
   
   
       3 . The internal combustion engine of  claim 2  wherein said coupling means also comprises a rod that reciprocates with said seesaw movement of said rocker arm and couples said rocker arm to said valve, said valve having a stem that has a pair of facing shoulders that sandwich said rod, one of said rod and said stem having a hole therethrough, the other of said rod and said stem extending through said hole. 
   
   
       4 . A rocker arm assembly for opening and closing a valve having a stem in a reciprocating, internal combustion engine, comprising:
 a camshaft arranged to rotate with said engine and having first and second attached cams,   a rocker arm mounted on a pivot and having a pair of cam followers, namely a tip and a seat,   said tip of said rocker arm being arranged to follow said first cam, and said seat of said rocker arm being arranged to follow said second cam so that said rocker arm will rock back and forth in a seesaw movement when said engine runs,   a rod attached to said rocker arm and arranged to reciprocate in response to said seesaw movement of said rocker arm,   said stem of said valve being attached to said rod so that as said camshaft rotates, said second cam first urges said seat of said rocker arm and said rocker arm to move in a first direction, thereby causing said rod to open said valve, then said first cam urges said tip of said rocker arm and said rocker arm to move in the opposite direction, thereby closing said rod to close said valve   whereby strong valve springs do not have to be compressed during engine operation, resulting in improved engine efficiency through reduced fuel consumption, a lighter engine, lower engine wear, less heat, and improved engine performance.   
   
   
       5 . The assembly of  claim 4 , further including a spring interposed between the end of said stem and said pin. 
   
   
       6 . The assembly of  claim 4 , further including a fastener affixed to said stem for retaining said spring. 
   
   
       7 . The assembly of  claim 6  wherein said fastener is selected from the group consisting of adjustable and non-adjustable fasteners. 
   
   
       8 . The assembly of  claim 4  wherein said stem of said valve has a pair of facing shoulders that are moved in respectively opposite directions by said rod. 
   
   
       9 . A rocker arm assembly for opening and closing a valve with a stem in a reciprocating, internal combustion engine, comprising:
 a rocker arm mounted on a pivot and arranged to rock back and forth in a seesaw movement,   said rocker arm having a pair of cam followers, namely a tip and a seat,   a pin being attached to said rocker arm and arranged to reciprocate in response to said seesaw movement of said rocker arm,   said stem of said valve being attached to said pin,   said arm being arranged to rotate about said pivot,   said tip being arranged to follow a first cam,   said seat being arranged to follow a second cam,   said first cam being attached to a first camshaft,   said second cam being attached to a second camshaft, said first and said second camshafts being arranged to rotate synchronously with the crankshaft of said engine,   so that as said second camshaft rotates, said second cam urges said seat and said arm to move in a first direction, thereby opening said valve, and as said first camshaft rotates, said first cam urges said tip and said arm to move in the opposite direction, thereby rotating said arm in a second direction and closing said valve,   whereby strong valve springs do not have to be compressed during engine operation, resulting in improved engine efficiency through reduced fuel consumption, a lighter engine, lower engine wear, less heat, and improved engine performance.   
   
   
       10 . The assembly of  claim 9 , further including a spring interposed between the end of said stem and said pin. 
   
   
       11 . The assembly of  claim 9 , further including a fastener affixed to said stem for retaining said spring. 
   
   
       12 . The assembly of  claim 11  wherein said fastener is selected from the group consisting of adjustable and non-adjustable fasteners. 
   
   
       13 . The assembly of  claim 9  wherein said stem of said valve has a pair of facing shoulders that are moved in respectively opposite directions by said rod. 
   
   
       14 . A method for opening a valve in a reciprocating, internal combustion engine, comprising:
 providing a valve with a stem, said valve being arranged to close a port in a cylinder when said valve is in a closed position and open said port when said valve is in a closed position,   providing a rocker arm having two cam followers, namely, a tip and a seat, said rocker arm mounted on a first shaft and being arranged to pivot on said first shaft,   providing a first cam having a first lobe and arranged to rotate in response to operation of said engine,   providing a second cam having a second lobe and arranged to rotate in response to operation of said engine,   said tip and said seat of said rocker arm being arranged to follow said first and second lobes of said first and second cams so that said rocker arm reciprocates in response to rotation of said engine,   providing a rod, said rod being attached to said stem of said valve and said rocker arm and arranged to cause said valve to open and close in response to reciprocation of said rocker arm,   so that when said tip is urged by said first cam, said valve is urged into a closed position, and when said seat is urged by said second cam, said valve is urged into an open position,   whereby strong valve springs do not have to be compressed during engine operation, resulting in improved engine efficiency through reduced fuel consumption, a lighter engine, lower engine wear, less heat, and improved engine performance.   
   
   
       15 . The method of  claim 14 , further including a spring interposed between an end of said stem and said pin. 
   
   
       16 . The method of  claim 14 , further including a fastener affixed to said stem for retaining said spring. 
   
   
       17 . The method of  claim 16  wherein said fastener is selected from the group consisting of adjustable and non-adjustable fasteners. 
   
   
       18 . The method of  claim 14  wherein said stem of said valve has a pair of facing shoulders that are moved in respectively opposite directions by said rod. 
   
   
       19 . The method of  claim 14  wherein said first and second cams are mounted on a common camshaft. 
   
   
       20 . The method of  claim 14  wherein said first and second cams are mounted on first and second camshafts, respectively. 
   
   
       21 . The method of  claim 14  wherein said stem of said valve extends through a hole in said rod. 
   
   
       22 . The method of  claim 14  wherein one of said first and second lobes of said first and second cams is relatively long and the other of said lobes is relatively short.