title: Comparison of particle mass and solid particle number (SPN) emissions from a heavy-duty diesel vehicle under on-road driving conditions and a standard testing cycle.
abstract: It is important to understand the differences between emissions from standard laboratory testing cycles and those from actual on-road driving conditions, especially for solid particle number (SPN) emissions now being regulated in Europe. This study compared particle mass and SPN emissions from a heavy-duty diesel vehicle operating over the urban dynamometer driving schedule (UDDS) and actual on-road driving conditions. Particle mass emissions were calculated using the integrated particle size distribution (IPSD) method and called MIPSD. The MIPSD emissions for the UDDS and on-road tests were more than 6 times lower than the U.S. 2007 heavy-duty particulate matter (PM) mass standard. The MIPSD emissions for the UDDS fell between those for the on-road uphill and downhill driving. SPN and MIPSD measurements were dominated by nucleation particles for the UDDS and uphill driving and by accumulation mode particles for cruise and downhill driving. The SPN emissions were ∼ 3 times lower than the Euro 6 heavy-duty SPN limit for the UDDS and downhill driving and ∼ 4-5 times higher than the Euro 6 SPN limit for the more aggressive uphill driving; however, it is likely that most of the "solid" particles measured under these conditions were associated with a combination release of stored sulfates and enhanced sulfate formation associated with high exhaust temperatures, leading to growth of volatile particles into the solid particle counting range above 23 nm. Except for these conditions, a linear relationship was found between SPN and accumulation mode MIPSD. The coefficient of variation (COV) of SPN emissions of particles >23 nm ranged from 8 to 26% for the UDDS and on-road tests.
authors: Department of Mechanical Engineering, and ‡Center for Environmental Research and Technology (CE-CERT), College of Engineering, University of California Riverside , Riverside, California 92521, United States.
authors: Zhongqing
authors: Z
authors: Zheng
authors: Thomas D
authors: TD
authors: Durbin
authors: Jian
authors: J
authors: Xue
authors: Kent C
authors: KC
authors: Johnson
authors: Yang
authors: Y
authors: Li
authors: Shaohua
authors: S
authors: Hu
authors: Tao
authors: T
authors: Huai
authors: Alberto
authors: A
authors: Ayala
authors: David B
authors: DB
authors: Kittelson
authors: Heejung S
authors: HS
authors: Jung
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001334:Automobile Driving; D008970:Molecular Weight; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D001335:Vehicle Emissions / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions