461663 A Rational Pathway for Generic Three-Way Catalyst Model Development in Stoichiometric Natural Gas Engines

Monday, November 14, 2016: 4:30 PM
Franciscan A (Hilton San Francisco Union Square)
Jian Gong, Di Wang, Junhui Li and Neal Currier, Cummins Inc., Columbus, IN

Three-way Catalysts have been widely used on stoichiometric natural gas engines for CO, hydrocarbon and NOx 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.

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