Automotive catalyst state control method

摘要

A control system and method for controlling an engine (10) of an automotive vehicle having a catalyst (34) is set forth herein. The control system maintains the efficiency of the catalyst by monitoring the catalyst state and driving the catalyst state to a target point. A first oxygen sensor (50) generates a first oxygen signal. A second oxygen sensor (52) downstream of the catalyst generates a second oxygen signal. A controller (12) is programmed to perform the steps of determining a catalyst state having a maximum value, a minimum value, and a target point therebetween; determining a commanded air-fuel ratio to drive the catalyst state to the target point; and operating the engine with the commanded air-fuel ratio.