Evaluation of the time-resolved nanoparticle emissions and the vehicle performance characteristics for a turbocharged gasoline direct-injection vehicle with a metal-foam gasoline particulate filter

The nanoparticle emissions from gasoline direct-injection engines are of concern because of the high particle number concentrations compared with those from a gasoline port fuel injection engine. A gasoline particulate filter is a potential solution for reducing the particulate matter emissions. In this study, a 2.0 l turbocharged gasoline direct-injection vehicle with a metal-foam-type gasoline particulate filter was tested using the New European Driving Cycle and steady vehicle operating conditions. The particle number concentration, the particle-size distribution and the filtration efficiency were determined using a condensation particle counter and a fast response differential mobility spectrometer (DMS500). The particle number emissions (particle numbers per vehicle travelling distance (particles/km)) over the New European Driving Cycle were 1.95 × 1012 particles/km for a base vehicle equipped with a three-way catalytic converter and 5.68 × 1011 particles/km for the additional installation of a gasoline particulate filter on the base gasoline direct-injection vehicle. The filtration efficiency of the particle number and the particulate matter mass reached approximately 71% and 67% respectively. The nucleation-mode particles in the size range less than 23 nm for the gasoline direct-injection vehicle equipped with a three-way catalytic converter were further reduced on installation of a gasoline particulate filter at the downstream position of the three-way catalytic converter. A sharp pressure drop between the gasoline particulate filter of 21.0 mbar was obtained at a vehicle speed of 120 km/h in the New European Driving Cycle. The exhaust gas temperature before the gasoline particulate filter reached around 380–610 °C at steady vehicle speeds of 60–120 km/h. The installation of the gasoline particulate filter has the potential to satisfy the Euro 6c particle number emissions regulations for light-duty gasoline direct-injection vehicles.