Application of an adaptive delay-compensated PI controller

A discrete, adaptive, delay-compensated PI control algorithm is developed and applied to air fuel ratio control of a spark ignition gasoline engine. Adaptation is necessary because of the significant variation in the air fuel ratio dynamic response as a function of engine operating condition. The delay-compensated PI controller tuning parameters are computed from the current system delay and time constant, which are determined from an engine speed and load map, using tuning rules derived from the discrete closed-loop transfer function of the system. The adaptive PI control algorithm is implemented using a rapid prototyping engine control computer and demonstrated on a Ford Duratec 2.0L I4 engine at the Villanova University Automotive Research Laboratory.