Dual lift rocker arm latch mechanism and actuation arrangement therefor

A valve control system for an internal combustion engine of the type including a cylinder head, a poppet valve moveable relative to the cylinder head between open and closed positions, and a camshaft having a first cam profile and a second cam profile formed thereon;

• said valve control system comprising a rocker arm assembly including a first rocker arm having a first cam follower in engagement with the first cam profile, and a second rocker arm having a second cam follower in engagement with the second cam profile;
• said valve control system further comprising the cylinder head including a fulcrum location operable to provide a source of pressurized fluid;
• said first rocker arm defining, toward a first axial end thereof, a fulcrum surface, adapted for pivotal engagement with said fulcrum location;
• said first rocker arm further defining, adjacent said fulcrum surface a pivot location whereby said second rocker arm pivots relative to said first rocker arm about said pivot location;
• said first rocker arm includes, toward a second axial end thereof, a latch assembly including a latch member moveable between latched and unlatched conditions relative to a latch surface defined by an adjacent portion of said second rocker arm;
• a spring biasing said latch member toward one of said latched and unlatched conditions, and said latch assembly defining a pressure chamber operable to bias said latch member toward the other of said latched and unlatched conditions;
• characterized by:
• (a) said first rocker arm defining a fluid passage having a first end in open fluid communication with said fulcrum surface, said first end of said fluid passage being operable to receive pressurized fluid from said source;
• (b) said fluid passage having a second end in open fluid communication with said pressure chamber of said latch assembly;
• and
• (c) said second axial end of said first rocker arm including an alignment feature that cooperates with said latch member to ensure proper alignment of said latch member with said latch surface.