Transmission ratio change control during mode transitions

摘要

Systems and methods for coordinating control of a DISI engine and automatic transmission determine the current and next engine operating modes and selectively modify or delay a requested transmission ratio change based on the current operating mode of the engine. Ratio changes requested during closed loop stoichiometric operation and during NOx purging cycles are commanded without delay while ratio changes requested during transitions between lean mode operation and stoichiometric operation may be delayed or the current operating mode extended to permit the ratio change to complete. Torque modulation may be provided during the ratio change using air, fuel, and/or spark control depending upon the engine operating mode.