Evaluation of regulated, particulate, and BTEX emissions inventories from a gasoline direct injection passenger car with various ethanol blended fuels under urban and rural driving cycles in Korea

In this study, the regulated, particulate, and unregulated emissions, and the fuel economy (FE) from a direct injection spark ignition (DISI) vehicle were investigated on a chassis dynamometer. Two vehicle test cycles, the congested urban (NIER03) and rural modes (NIER09), which reflect vehicle driving patterns in Korea, were tested with varying ethanol contents of gasoline (E0), and low- (E10), medium- (E30 and E50), and high-ethanol blended fuels (E85). The particle number (PN) concentration from E0 was substantially reduced by one or two orders of magnitude with medium- or high-ethanol blended fuels, respectively. The E10 fuel showed the highest PN concentration because of the physicochemical mixture properties of the azeotropic characteristics. As the ethanol fraction increased, the particle sizes shifted to smaller sizes that were dependent on the vehicle test modes and oxygen proportions in the fuels. The regulated and unregulated emissions showed close relationships with the vehicle test modes and ethanol blends. Vehicle running with frequent idle-stops at an extremely low speed and dynamic transient driving under NIER03 showed higher BTEX emissions than the NIER09 mode, and produced lower emission levels due to the higher oxygen and lower aromatic proportions of the ethanol blends. Compared to the NIER03 mode, the CO₂ emissions and FEs under the NIER09 mode were substantially improved, with a higher vehicle speed and more energy efficient engine operation points. The low energy contents of the E85 fuel resulted in slight increases in the CO₂ emissions and reductions in the FEs of the NIER modes.