Periodic Operation of Three-Way Catalysts: From Synthetic Gas Bench Testing to Real-World Engine Performance

Abstract

This study utilized a synthetic gas test bench (SGB) and two engine test benches (ETBs) to evaluate the periodic operation of an industrially relevant three-way catalyst formulation. The goal was to bridge the gap between laboratory-scale testing and real-world applications, ensuring the reliability of catalysts in engine environments under periodic conditions. SGB testing showed significant increases in NO, CO, and hydrocarbon conversion and N₂ selectivity under dynamic operation compared to stoichiometric steady-state conditions. Despite differences in ETB testing due to the realistic conditions, notable improvements in pollutant conversion were achieved. Challenges included inaccurate control of the mean air–fuel equivalence ratio (AFR) by the engine control unit and the AFR sensor. The findings underscore the importance of harmonizing engine operation with formulation-governed catalyst properties to minimize tailpipe emissions. Periodic operation emerges as a promising technique for enhancing catalyst efficiency in varying engine conditions.