Stoichiometric Air-Fuel Ratio Control Analysis

A great deal of current automotive engineering effort involves the development of three-way catalyst-based emission control systems that seek to minimize fuel consumption while simultaneously meeting stringent exhaust emission standards. Mitigation of emissions is enhanced in a three-way catalyst system when the system air-fuel ratio (A/F) is in proximity to ideal burning or stoichiometry.

This paper is concerned with extending methods used for determining engine calibrations to closed-loop systems with three-way catalysts. The paper presents a simulation model that employs experimentally obtained data to characterize the A/F control loop.