NOx EMISSION CONTROL FOR A CONTROLLED AUTO-IGNITION FOUR-SRTOKE INTERNAL COMBUSTION ENGINE

摘要

A four-stroke internal combustion engine is operated in controlled auto-ignation mode by any of a variety of valve control strategies conducive to controlled auto-ignation conditions in conjunction with in-cylinder fuel charges that are at either stoichiometric or lean of stoichiometric air-fuel ratios. A measure of engine NOx emission is provided and when it crosses a predetermined threshold, the in-cylinder fuel charge is transitioned from the operative one of the stoichiometric or lean stoichiometric air-fuel ratios to the inoperative one of the stoichiometric or lean of stoichiometric air-fuel ratios.