Real-world emissions measurements of a GDI passenger car with and without a gasoline particulate filter

A new study aims to evaluate the effects of a gasoline particulate filter on NOx and PN emissions from GDI passenger vehicles under real driving conditions. Emissions have been the focus of worldwide legislation for more than 25 years. Regulation initially concentrated on gaseous emissions of carbon monoxide, hydrocarbons and NOx. However, particles emitted from vehicles and from other sources are now accepted as having an impact on air quality and on human health.

Traditionally port fuel injected (PFI) gasoline vehicles generally emit very low levels of particulates because the fuel is well mixed with the intake air before combustion. Gasoline direct injection (GDI) vehicles have been increasing in market share due to their positive contribution to improving the average fleet fuel economy. GDI vehicles share some features with diesel vehicles in that the fuel is injected directly into the cylinder and has much less time to evaporate and mix before combustion starts, and this can lead to particulate formation.