Dual control valve

A control apparatus for an engine valve, the engine valve being an intake/exhaust valve, the engine valve for admitting and exhausting a fluid mixture to and from a combustion chamber of an internal combustion engine, comprising;

• a selectively actuatable controller being in fluid communication with a source of pressurized actuating fluid and being in fluid communication with a substantially ambient actuating fluid reservoir, the controller having a first control valve for selectively independently porting actuating fluid to and venting actuating fluid from a drive piston, the drive piston being operably coupled to the engine valve, and a second control valve for selectively independently porting actuating fluid to and venting actuating fluid from a boost piston, the boost piston being selectively operably coupled to the engine valve.

A method of control for an engine valve, the engine valve being an intake/exhaust valve, the engine valve admitting and exhausting a fluid mixture into a combustion chamber of an internal combustion engine, comprising:

• fluidly coupling a selectively actuatable controller being with a source of pressurized actuating fluid and with a substantially ambient actuating fluid reservoir;
• selectively independently porting actuating fluid to and venting actuating fluid from a drive piston, the drive piston being operably coupled to the engine valve, by means of a first control valve, and
• selectively independently porting actuating fluid to and venting actuating fluid from a boost piston by means of a second control valve and selectively operably coupling the boost piston to the engine valve.

The method of claim 62 including generating an engine valve closing force by cooperatively coupling the force generated on the return piston by the pressurized actuating fluid and the bias exerted by the engine valve return spring.

A valve actuator for actuating an engine valve, the engine valve being an intake/exhaust valve, the engine valve admitting and exhausting a fluid mixture into a combustion chamber of an internal combustion engine, comprising:

• a drive piston being operably coupled to the engine valve, the drive piston being selectively fluidly couplable to a controller, the controller having a first control valve for selectively independently porting actuating fluid to and venting actuating fluid from the drive piston;
• and
• a boost piston being selectively operably coupled to the engine valve, the boost piston being selectively fluidly couplable to a controller, the controller having a second control valve for selectively independently porting actuating fluid to and venting actuating fluid from the boost piston.