EARLY INTAKE VALVE CLOSING AND VARIABLE VALVE TIMING ASSEMBLY AND METHOD

摘要

An early intake valve closing (EIVC) and variable valve timing (VVT) assembly and method are provided for an internal combustion engine. The method includes operating an intake valve to open and close an intake port and allow intake gas to enter a cylinder of the internal combustion engine containing a piston, where the timing of the closing of the intake valve occurs at or before bottom dead center (BDC) of the compression stroke of the piston. The method further includes selectively extending duration of the opening of the intake port by an amount that delays closing timing of the intake valve until after BDC of the piston compression stroke. An assembly for EIVC and VVT includes a cylinder head including an intake valve and intake port and a rotatably mounted camshaft including an intake lobe operatively connected to the intake valve to periodically move the valve into the first and second positions. The intake lobe is shaped such that the timing of the closing position occurs at or before BDC of a compression stroke of the piston. The assembly further includes a selectively activatable VVT assembly having an actuator that operatively engages the intake valve before the intake valve reaches the closed position to extend duration of the intake valve opening until after BDC of the piston compression stroke.