Characteristics of nanoparticle emission from a light-duty diesel vehicle during test cycles simulating urban rush-hour driving patterns

This study analyzed the characteristics of nanoparticle emissions from a light-duty diesel vehicle in NIER-06 and NIER-09 test cycles, which include acceleration, deceleration, and idling phases without cruise driving phase and thus simulate urban driving patterns during rush hour in South Korea. In general, the tested diesel vehicle emitted more particles as acceleration increased. Since NIER-06 test cycle showed a higher average acceleration than NIER-09 test cycle, the tested diesel vehicle emitted more particles, by 17–31%, per unit distance traveled in NIER-06 test cycle than in NIER-09. When the acceleration phases of NIER-06 and NIER-09 test cycles were categorized into two groups by considering gear shift change, the tested diesel vehicle emitted more particles, by approximately 60%, per unit distance traveled at the acceleration phases with the speed change of lower than 20 km/h, i.e., where it was assumed that gear shift change did not occur during acceleration, than at the acceleration phases with the speed change of higher than 20 km/h, i.e., where it was assumed that gear shift change occurred more than once. Achieving a high average velocity of traffic flow or minimizing sudden acceleration for smooth urban traffic will be of great help in reducing particle emissions from light-duty diesel vehicles.