(216f) A Rational Pathway for Generic Three-Way Catalyst Model Development in Stoichiometric Natural Gas Engines

Three-way Catalysts have been widely used on stoichiometric natural gas engines for CO, hydrocarbon and NO_x emission control. A generic TWC model is highly desirable for design of aftertreatment systems, development of advanced control strategies and on-board diagnostics (OBD), and TWC architecture selection. However, there are many challenges in developing a generic TWC model. First, TWCs typically operate under dynamic conditions (e.g. fast lean/rich dithering). Second, TWC chemistry consists of a complex reaction network. In this work, a rational pathway has been established to develop a generic TWC model that is capable of capturing the complicated chemistry as well as transient behaviors. This TWC model includes an OSC sub-model and PGM related kinetic sub-model which is sensitive to catalyst state. The former is calibrated based on dynamic oxygen storage capacity (OSC) characterization performed on a bench reactor. The latter is calibrated base on a complex steady state light-off performance protocol developed by the authors. The full model with calibrated kinetics is finally validated by dithering tests performed on a transient reactor and engine test data. This approach is found to be very capable and effective for generic TWC model development.