Study of Oxygen Storage Performance Modeling of Catalyst Degradation 2006-01-0412
Oxygen storage performance is modeled with the goal of optimizing the performance of three-way catalysts and developing an on-board catalyst degradation diagnosis (OBD) system. Oxygen storage performance is closely correlated with catalyst performance and degradation, and thus can serve as an excellent indicator for accessing the performance of catalysts[1, 2, 3, 4, 5 and 6].
In experiments using actual exhaust gas, it was found that the rate of oxygen storage and discharge under actual operating conditions exhibited sufficiently fast chemical reactions and were dependent on the supply rate of reactant species. We also found that the higher the catalyst temperature, the greater the oxygen storage capacity.
These experimental results were modeled in a general control system development tool environment. Simulating the exhaust gas using the model, we found that when the amount of oxygen flowing into the catalyst exceeded the oxygen storage capacity set in the model, the NOx purification efficiency declined. The simulation results closely replicated the experimental results, revealing that reduction of the oxygen storage capacity is linked to the reduction of catalyst performance near stoichiometry.