Real-world measurement and mechanical-analysis-based verification of NO x and CO 2 emissions from an in-use heavy-duty vehicle

摘要

A portable emission measurement system (PEMS) was used to measure the real-world driving emissions pertaining to a Japanese middle-sized heavy-duty vehicle. The testing was performed with the vehicle being driven in the metropolitan area of Tokyo in four seasons (January, June, August, and November) to analyze the seasonal dependence of NO x and CO 2 emissions. The experimental results indicated that the amount of NO x emissions was particularly high in the cold season owing to the slow starting of the NO x after-treatment systems, which is to say the exhaust gas recirculation and urea-selective-catalytic-reduction systems, under low-ambient-temperature conditions. In real-world driving, a high acceleration pattern was observed in the low-speed region which is not considered in the world harmonized vehicle cycle, which is the worldwide official driving mode in the chassis dynamometer experiment. Finally, the transient emission tables for NO x and CO 2 were constructed based on the PEMS measurement results and the classical mechanic theory. The constructed tables replicated well the experimental results in all the considered conditions involving different ambient temperatures and locations. The proposed approach can be used to evaluate emission inventories in the future.