Real-world measurement and mechanical-analysis-based verification of NOx and CO2 emissions from an in-use heavy-duty vehicle

Abstract

Abstract. A portable emission measurement system (PEMS) was used to\nmeasure the real-world driving emissions pertaining to a Japanese\nmiddle-sized heavy-duty vehicle. The testing was performed with the vehicle\nbeing driven in the metropolitan area of Tokyo in four seasons (January,\nJune, August, and November) to analyze the seasonal dependence of NO x \nand CO 2 emissions. The experimental results indicated that the amount\nof NO x emissions was particularly high in the cold season owing to the\nslow starting of the NO x after-treatment systems, which is to say the exhaust\ngas recirculation and urea-selective-catalytic-reduction systems, under low-ambient-temperature conditions. In real-world driving, a high\nacceleration pattern was observed in the low-speed region which is not\nconsidered in the world harmonized vehicle cycle, which is the worldwide\nofficial driving mode in the chassis dynamometer experiment. Finally, the\ntransient emission tables for NO x and CO 2 were constructed based\non the PEMS measurement results and the classical mechanic theory. The\nconstructed tables replicated well the experimental results in all the\nconsidered conditions involving different ambient temperatures and\nlocations. The proposed approach can be used to evaluate emission\ninventories in the future.