Variability in operation-based NO_x emission factors with different test routes, and its effects on the real-driving emissions of light diesel vehicles

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• 作者：Taewoo Lee ; Junhong Park ; Sangil Kwon ; Jongtae Lee ; Jeongsoo Kim
• 关键词：On-road emissions ; Nitrogen oxide (NOx) ; Light-duty diesel vehicles ; Operating conditions ; Road traffic conditions
• 刊名：Science of the Total Environment
• 出版年：2013
• 出版时间：1 September, 2013
• 年：2013
• 卷：461-462
• 期：Complete
• 页码：377-385
• 全文大小：582 K

文摘

The objective of this study is to quantify the differences in NO_x emissions between standard and non-standard driving and vehicle operating conditions, and to estimate by how much NO_x emissions exceed the legislative emission limits under typical Korean road traffic conditions. Twelve Euro 3-5 light-duty diesel vehicles (LDDVs) manufactured in Korea were driven on a chassis dynamometer over the standard New European Driving Cycle (NEDC) and a representative Korean on-road driving cycle (KDC). NO_x emissions, average speeds and accelerations were calculated for each 1-km trip segment, so called averaging windows. The results suggest that the NO_x emissions of the tested vehicles are more susceptible to variations in the driving cycles than to those in the operating conditions. Even under comparable operating conditions, the NO_x control capabilities of vehicles differ from each other, i.e., NO_x control is weaker for the KDC than for the NEDC. The NO_x emissions over the KDC for given vehicle operating conditions exceed those over the NEDC by more than a factor of 8. Consequently, on-road NO_x emission factors are estimated here to exceed the Euro 5 emission limit by up to a factor of 8, 4 and 3 for typical Korean urban, rural, and motorway road traffic conditions, respectively. Our findings support the development of technical regulations for supplementary real-world emission tests for emission certification and the corresponding research actions taken by automotive industries.