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.

中文翻译：

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通过实验室规模的实验评估柴油选择性催化还原催化剂系统的总性能

根据日本最近建立的排放标准，已经发现一些柴油机排放过量的NOx，这主要是由于车载催化剂的性能较差。在这项研究中，我们通过在模拟反应气体条件下在实验室中对单一和组合催化剂进行活性测试，研究了符合日本最新排放法规的重型车辆排气净化系统总体性能的评估方法。对于单选择性催化还原（SCR）催化剂和SCR催化剂与柴油氧化催化剂和氨气滑脱催化剂组合使用，评估了模拟老化样品相对于新鲜样品的降解率。结果表明，SCR催化剂的降解对系统的整体NOx净化性能有重大影响。研究结果和评价方法为柴油车发动机废气净化技术的改进提供了有益的参考。