Investigation into the Role of Catalytic Converters on Tailpipe-out Nano-Scale Particulate Matter from Gasoline Direct Injection Engine

Nanoparticle Filtration Characteristics of Advanced Metal Foam Media for a Spark Ignition Direct Injection Engine in Steady Engine Operating Conditions and Vehicle Test Modes

“…The particle formation of the GDI vehicle increased sharply, compared to that of the GPF-GDI vehicle at steep acceleration points, although this mode included a hot engine start followed by fully warmed-up driving. The particle spikes of the base GDI vehicle during the aggressive acceleration points were due to the combination of the rich mixture formation and shifting of gears by the automatic transmission [18,21,24,30,31,[33][34][35]. The PN emissions of the GPF-GDI vehicle through the HWFET mode were significantly lower than those of the base GDI vehicle.…”

“…The particle reduction characteristics of the spark ignition direct injection (SIDI) engine with a three-way catalytic converter (TWC) have been well investigated in previous studies [33][34][35]. Substantial reduction of the sub-23 nm particles was observed in the downstream position of the TWC.…”

“…The amount of exhaust particles in the engine-out position increased sharply with the higher engine speed and load. However, substantial reduction of particle concentration was attained after the TWC and GPF positions, which were mainly associated with the oxidation and storage process of the volatile compounds and solid particles in the exhaust after-treatment systems [33][34][35][39][40][41][42]. Figure 5 shows the particle size distributions of the GDI and GPF at three sampling positions.…”

“…The DMS500 equipped with heated sample line and two stage dilution systems allowed direct sampling from the exhaust gas. The detectable particle size ranges of this equipment were 5-1000 nm and the time response was 200 milliseconds [18,[33][34][35]. The specifications of the tested fuel are presented in Table 2.…”

“…Particle size distributions are generally classified into three modes: nucleation mode (5 nm < dp < 30 nm), accumulation mode (30 nm < dp < 1000 nm) and coarse mode (1000 nm < dp). Exhaust particles containing volatile organic compounds that are less than 23 nm in size formed during combustion in locally rich regions are substantially oxidized in the TWC, while almost all of the accumulation mode particles are passed through the catalyst without purification [25,27,[33][34][35]. Therefore, a cost-effective gasoline particulate filter (GPF) can be adopted for GDI vehicles to reduce the nano-PM emissions to satisfy future PN emission regulations [10,27,[29][30][31][36][37][38][39].…”