Direct acting differential two-step valve train

摘要

A direct acting two-step valve train uses direct acting switching valve lifters combined with high and low lift or no lift cams providing differential valve lifts for dual intake valves of cylinders actuated by the low lift cams. The combination provides various alternative operating modes utilizing the charge enhancing qualities of differential intake valve lifts in low lift operation. These modes include (1) high lift to differential low valve lift and (2) high lift to low lift on one bank and high lift or no lift (deactivated) on the other. A cam phaser may also be included to vary cam phasing on single or dual camshafts.