Reduction of particle emissions from gasoline vehicles with direct fuel injection systems using a gasoline particulate filter

Abstract

To analyze the effect of a gasoline particulate filter (GPF) attachment on the emissions of gasoline direct injection (GDI) vehicles, this study compares the emission results of three types of vehicles: conventional GDI vehicles, vehicles with a GPF at the close-couple catalytic converter (CCC), and vehicles with a GPF at the under-floor catalytic converter (UCC). Regulated particulate matter (PM) and particle number (PN) emitted from test vehicles were measured using gravimetric methods and condensation particle counter (CPC) equipment. In addition, this study analyzed nanoparticle size distribution, organic carbon (OC), elemental carbon (EC), and ammonia (NH3) using EEPS, OC-EC analyzer, and HFIR equipment. In cases of regulated particle emissions, both PM and PN satisfy EURO 6c and are reduced when a GPF is attached. Particulate emissions are especially reduced when the GPF is attached at the UCC position. This is believed to be why a soot layer is formed in stable flow. Emissions of nanoparticles and OC/EC are high in US06 mode at high driving speed. This is considered to be the influence of the regeneration of the GPF as the temperature of the exhaust gas rises. The emission of NH3 is also highest in US06 mode, which is related to catalytic conversion efficiency.