Abstract: A system for varying valve timing; i.e. the rotational angle of the crankshaft during which an intake or an exhaust valve of a cylinder of a reciprocating internal combustion engine is open which results in varying valve overlap, and for varying valve lift of such intake and exhaust valves. A desmodromic cam and cam follower convert rotation of a cam shaft to reciprocating rotation, or oscillation, of the cam follower. The reciprocating rotation of the cam follower is converted by the interaction of a secondary cylindrical cam, a cylindrical control ring, and a reciprocating member to linear motion of the reciprocating member which reciprocating member is operatively connected to a poppet valve. Timing and lift of the reciprocating member and valve are variable over predetermined limits as a function of engine rpm and load by rotation of the cylindrical control ring. Each valve train positively closes as well as opens its associated valve.

Abstract: A system for varying valve timing; i.e. the rotational angle of the crankshaft during which an intake or an exhaust valve of a cylinder of a reciprocating internal combustion engine is open which results in varying valve overlap, and for varying valve lift of such intake and exhaust valves. A desmodromic cam and cam follower convert rotation of a cam shaft to reciprocating rotation, or oscillation, of the cam follower. The reciprocating rotation of the cam follower is converted by the interaction of a secondary cylindrical cam, a cylindrical control ring, and a reciprocating member to linear motion of the reciprocating member which reciprocating member is operatively connected to a poppet valve. Timing and lift of the reciprocating member and valve are variable over predetermined limits as a function of engine rpm and load by rotation of the cylindrical control ring. Each valve train positively closes as well as opens its associated valve.