Total Performance Evaluation Of A Diesel Selective Catalytic Reduction Catalyst System Through Laboratory-Scale Experiments

Some diesel engines have been found to emit excessive amounts of NOx according to the recently established emission standards in Japan, primarily due to the poor performance of on-board catalysts. In this study, we investigated an evaluation method of the overall performance of an exhaust gas purification system in a heavy-duty vehicle that complies with Japan's latest emission regulations through activity tests of single and combined catalysts in a laboratory under simulated reaction gas conditions. The degradation rate of a simulated aged sample relative to a fresh sample was evaluated for a single selective catalytic reduction (SCR) catalyst and an SCR catalyst combined with a diesel oxidation catalyst and an ammonia slip catalyst. The results showed that the degradation of the SCR catalyst had a significant impact on the overall NOx purification performance of the system. The results and the evaluation method provide a useful reference for the improvement in the exhaust gas purification technology used in diesel vehicle engines.