Euro 6 Unregulated Pollutant Characterization and Statistical Analysis of After-Treatment Device and Driving-Condition Impact on Recent Passenger-Car Emissions

This study aims to measure and analyze unregulated compound emissions for two Euro 6 diesel and gasoline vehicles. The vehicles were tested on a chassis dynamometer under various driving cycles: Artemis driving cycles (urban, road, and motorway), the New European Driving Cycle (NEDC) and the World Harmonized Light-Duty Test Cycle (WLTC) for Europe, and world approval cycles. The emissions of unregulated compounds (such as total particle number (PN) (over 5.6 nm); black carbon (BC); NO2; benzene, toluene, ethylbenzene, and xylene (BTEX); carbonyl compounds; and polycyclic aromatic hydrocarbons (PAHs)) were measured with several online devices, and different samples were collected using cartridges and quartz filters. Furthermore, a preliminary statistical analysis was performed on eight Euro 4-6 diesel and gasoline vehicles to study the impacts of driving conditions and after-treatment and engine technologies on emissions of regulated and unregulated pollutants. The results indicate that urban conditions with cold starts induce high emissions of BTEX and carbonyl compounds. Motorway conditions are characterized by high emissions of particle numbers and CO, which mainly induced by gasoline vehicles. Compared with gasoline vehicles, diesel vehicles equipped with catalyzed or additive DPF emit fewer particles but more NOx, and carbonyl compounds.