School of Automotive studies, Tongji University, Shanghai 201804, China.
School of Automotive studies, Tongji University, Shanghai 201804, China.
J Environ Sci (China). 2019 Oct;84:166-173. doi: 10.1016/j.jes.2019.05.001. Epub 2019 May 14.
The primary purpose of this study was to investigate the effect of a catalyzed continuously regenerating trap (CCRT) system composed of a diesel oxidation catalyst (DOC) and a catalyzed diesel particulate filter (CDPF) on the main gaseous and particulate emissions from an urban diesel bus, as well as the durability performance of the CCRT system. Experiments were conducted based on a heavy chassis dynamometer, and a laboratory activity test as well as X-ray photoelectron spectroscopy (XPS) test were applied to evaluate the changes of the aged CCRT catalyst. Results showed that the CCRT could reduce the CO by 71.5% and the total hydrocarbons (THC) by 88.9%, and meanwhile promote the oxidation of NO. However, the conversion rates for CO and THC dropped to 25.1% and 55.1%, respectively, after the CCRT was used for one year (~60,000 km), and the NO oxidation was also weakened. For particulate emissions, the CCRT could reduce 97.4% of the particle mass (PM) and almost 100% of the particle number (PN). The aging of the CCRT resulted in a reduced PM trapping efficiency but had no observable effect on the PN; however, it increased the proportion of nucleation mode particles. The activity test results indicated that the deterioration of the CCRT was directly relevant to the increase in the light-off temperatures of the catalyst for CO, CH and NO. In addition, the decreased concentrations of the active components Pt and Pt in the catalyst are also important factors in the CCRT deterioration.
本研究的主要目的是考察由柴油氧化催化剂（DOC）和催化式柴油颗粒过滤器（CDPF）组成的催化连续再生捕集器（CCRT）系统对城市柴油客车主要气态和颗粒排放物的影响，以及 CCRT 系统的耐久性性能。实验基于重型底盘测功机进行，并进行了实验室活性测试和 X 射线光电子能谱（XPS）测试，以评估老化的 CCRT 催化剂的变化。结果表明，CCRT 可将 CO 降低 71.5%，总碳氢化合物（THC）降低 88.9%，同时促进 NO 的氧化。然而，在 CCRT 使用一年（约 60,000 公里）后，CO 和 THC 的转化率分别降至 25.1%和 55.1%，NO 的氧化也减弱。对于颗粒排放物，CCRT 可减少 97.4%的颗粒质量（PM）和几乎 100%的颗粒数量（PN）。CCRT 的老化导致 PM 捕集效率降低，但对 PN 没有明显影响；然而，它增加了成核模态颗粒的比例。活性测试结果表明，CCRT 的恶化与催化剂对 CO、CH 和 NO 的起燃温度升高直接相关。此外，催化剂中活性成分 Pt 和 Pt 的浓度降低也是 CCRT 恶化的重要因素。
