Optimization of TWC Design for Various Engine Operation Conditions 2019-01-1290

Three-way catalysts (TWCs) for gasoline-powered vehicles commonly contain Pt group metals (Pt, Pd, and Rh) as active components and Al₂O₃ or OSC as supports, with Pd and Rh being most frequently employed in view of their high thermal durability. Hybrid electric vehicles (HEVs) have been recently developed to meet strict fuel efficiency regulations, by using feature engines that are much more energy-efficient than those of conventional gasoline vehicles and lend themselves to fixed-point operation control. Therefore, the engine exhaust-induced stress experienced by TWCs in HEVs and the corresponding aging conditions are expected to differ from those in conventional vehicles, which, in turn, should be reflected by a change in the optimal catalyst design. Herein, to facilitate the design of optimum next-generation TWCs, we investigate the deterioration of these catalysts (Pt, Pd, Rh supported on Al₂O₃ or OSC) under various conditions reflecting different engine operation modes. The results shown that Pt catalysts are inferior to Rh and Pd catalysts after conventional high-temperature aging, while Pt/OSC outperforms Pd/OSC under low-temperature aging conditions. Thus, this work is expected to aid the design of TWCs for various engine operating conditions.