Method and apparatus for managing combustion mode transitions in an internal combustion engine

摘要

An internal combustion engine includes two-step variable lift control mechanisms configured to control magnitude of valve lift of intake and exhaust valves to one of two discrete steps including low-lift valve open positions and high-lift valve open positions. A method for operating the engine includes commanding a transition from a first combustion mode to a second combustion mode. Upon commanding the transition, closing of a plurality of secondary throttle valves configured to control intake airflow to a plurality of intake runners upstream of a plurality of intake valves is initiated. Positions of the plurality of secondary throttle valves are then adjusted to achieve a preferred air charge. The two-step variable lift control mechanisms are then commanded to switch from a first of the two discrete steps to a second of the two discrete steps.