METHOD (VERSIONS) AND SYSTEM OF SELECTIVE WITHDRAWAL FROM OPERATION OF ONE OR MORE ENGINE CYLINDERS

摘要

Methods and systems are provided for expediting purging of LP-EGR from an air intake system during conditions of decreasing engine load. During a tip-out, an EGR valve is closed while the engine is shifted to a VDE mode of operation to improve engine tolerance to EGR at lower engine loads and until the EGR is sufficiently purged. A non-VDE mode is resumed if higher engine loads are restored, else, a deceleration fuel shut-off mode is selected if the tip-out continues to zero load.