Fully variable valve train

A valve control system for an internal combustion engine of the type including a cylinder head, an engine poppet valve, and a valve actuating camshaft defining a cam profile;

• said valve control system comprising a rocker arm having a first portion fixed to pivot relative to said cylinder head and a second portion operable to transmit cyclic opening and closing motion to said engine poppet valve;
• a cam follower assembly including a first cam follower member in engagement with said cam profile, whereby cyclic rise and fall motion is transmitted from said cam profile to said first cam follower member in response to rotation of said camshaft;
• characterized by:
• (a) a cam member disposed for to and fro movement relative to said camshaft and defining a cam surface disposed in a generally face-to-face relationship to an engagement surface defined by said rocker arm;
• (b) said cam follower assembly including a second cam follower member in operable engagement with both said engagement surface defined by said rocker arm and said cam surface defined by said cam member, and being disposed therebetween, said cam follower assembly further including a rigid follower linkage interconnecting said first and second cam follower members, thus transmitting said cyclic rise and fall motion to said second cam follower member;
• (c) a control arrangement including a link member having one end (65a) fixed relative to said cam assembly and the other end operably associated with an input member to vary the to and fro position of said cam member;
• and
• (d) an adjustable timing linkage having one end fixed to said first cam follower member and operable, in response to a timing input motion, to advance or retard the point of contact of said first cam follower member on said cam profile.