An electromechanical VVA system for controlling the poppet valves in the
cylinder head of an internal combustion engine. The system varies valve
lift, duration, and phasing in a dependent manner for one or more banks
of engine valves. A rocker subassembly for each valve or valve pair is
pivotably disposed on a control shaft between the camshaft and the roller
finger follower. The control shaft may be displaced about a pivot axis
outside the control shaft to change the angular relationship of the
rocker subassembly to the camshaft, thus changing the valve opening,
closing, and lift. A plurality of control shafts for controlling all
valvetrains in an engine bank defines a control shaft assembly. The
angular positions of the individual control shafts may be tuned to
optimize the valve timing of each cylinder. The system is applicable to
the intake and exhaust camshafts of diesel and gasoline engines.