Department of Environmental Sciences/Center of Excellence in Environmental Studies , King Abdulaziz University , P.O. Box 80203, Jeddah 21589 , Saudi Arabia.
Environ Sci Technol. 2019 Oct 1;53(19):11345-11352. doi: 10.1021/acs.est.9b03053. Epub 2019 Sep 10.
Particulate and vapor phase emissions in the diluted exhaust of a light-duty diesel engine designed for Euro 5 application have been sampled. The engine was operated in three modes, and samples were collected from the exhaust without aftertreatment but also with aftertreatment by an exhaust oxidation catalyst and particle filter. The samples were analyzed by two-dimensional gas chromatography with time-of-flight mass spectral detection. The results show overall removal efficiencies for the organic compound mass by the combination of oxidation catalyst and particle filter of 50, 56, and 74% for the high-speed/high-load, low-speed/low-load, and high-speed/low-load conditions respectively. The results are clearly indicative of substantial repartitioning of the particulate and vapor components within the abatement devices and show an apparently reduced efficiency for the removal of high-molecular-weight alkanes under high-speed/high-load conditions relative to lower-molecular-weight compounds, although this may be due to alkane formation by thermocracking of other species. A notable feature is the presence of oxygenated compounds in the emissions, which are not present in the fuel. These are increased under high-speed/high-load conditions, and the results suggest the formation in the aftertreatment devices as well as in the combustion process.
对设计用于满足欧 5 排放标准的轻型柴油发动机稀释排气中的颗粒物和气相排放进行了采样。该发动机在三种模式下运行，采集了未经后处理以及经氧化催化剂和颗粒过滤器后处理的排气中的样本。采用二维气相色谱-飞行时间质谱检测法对样本进行了分析。结果表明，对于高速/高负荷、低速/低负荷和高速/低负荷条件，氧化催化剂和颗粒过滤器组合对有机化合物质量的总体去除效率分别为 50%、56%和 74%。结果清楚地表明，在减排装置内颗粒物和气相成分发生了大量再分配，并且在高速/高负荷条件下，相对于低分子量化合物，去除高分子烷烃的效率明显降低，尽管这可能是由于其他物质的热裂化形成了烷烃。一个显著的特点是排放物中存在含氧化合物，而这些化合物在燃料中并不存在。在高速/高负荷条件下，这些化合物的含量增加，这表明它们在后处理装置以及燃烧过程中形成。
