Effects of fuel-injection systems on particle emission characteristics of gasoline vehicles

Abstract

In this study, the particle emission characteristics of gasoline vehicles with four different types of spark ignition engines, i.e., port fuel-injection (PFI), 150-bar side-mounted gasoline direct-injection (GDI), 200-bar side-mounted GDI, and 200-bar center-mounted GDI vehicles, were evaluated using Federal Test Procedure-75 (FTP-75) and worldwide harmonized light vehicles test cycle (WLTC). Particulate matter (PM), particle number (PN), and organic carbon/elemental carbon ratio (OC/EC) were evaluated using a PM holder, a solid particle counting system, and an OC/EC analyzer. The results of the PM and PN emissions tests indicated that GDI 200-bar vehicles emitted less than GDI 150-bar vehicles, and center-mounted vehicles emitted less than side-mounted vehicles. PFI vehicles showed 15% higher PN emission rates compared with GDI vehicles during acceleration conditions in FTP-75 mode. Additionally, PN emissions in WLTC hot mode indicated that speed affects PFI vehicles more than GDI vehicles. Furthermore, PFI vehicles did not show significant PN emissions in a low-speed phase, even at high acceleration. PFI vehicles showed 15% higher PN emission rates compared with GDI vehicles while accelerating in FTP-75 mode. PFI and GDI side-mounted vehicles showed higher OC emission rates in hot mode than in cold mode.