Size-resolved engine exhaust aerosol characteristics in a metal foam particulate filter for GDI light-duty vehicle

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

“…Therefore, when metal foams with various pore sizes were fabricated into one filter, the particle capturing process inside the filter pore would be more uniformly improved, and the pressure drop through the GPF could be decreased in as a necessary [36][37][38][39]. Moreover, metal foam has a three-dimensional complex pore structure and an irregular strut surface because of the unique powder metallurgical manufacturing processes.…”

“…These processes form a large surface area, which enhances the mass transfer from the main flow to the strut surface. Therefore, the catalytic performance for exhaust gas treatment can be increased when metal foam is applied as a catalyst substrate [34,[36][37][38][39][40][41][42]. Table 3 shows the physical properties of the metal foam filter used in this test, with a total volume of 4.0 liters, a length of 280 mm, an inner diameter of 42.7 mm; an outer diameter of 142 mm and a total diameter of 160 mm with fixture and outer canning for the GPF.…”

“…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]. The physical characteristics of volume, space velocity, pressure drops, exhaust temperature for natural regeneration, and particle-filtering efficiency, including sub-23 nm particles that do not negatively affect vehicle exhaust emissions and fuel efficiency, should be considered for optimized performance [5,10,25,27,30,[36][37][38][39][40][41][42][43].…”

“…A two-brick under-floor catalytic converter (UCC) combined with the engine control strategies of double split injection (DSI) and spark timing retard was used to effectively lower the vehicle emissions during the cold-start phase. A metal foam-type GPF (Alantum, Seongnam, Korea), located 50 cm downstream from the outlet of the UCC, was applied to the test vehicle to evaluate the nanoparticle filtration efficiency of the GPF [39]. Particle size distributions and PN concentrations from the GDI engine were directly measured at three positions with heated sampling valves and sampling line for minimizing the loss of particles: (1) in front of the TWC position; (2) after the TWC position; and (3) after the GPF position using a differential mobility spectrometer (DMS500, CAMBUSTION, Cambridge, UK).…”

“…The metal foam has the shape of a circular annular tube, and exhaust gas flows radially from the inside to the outside of the annular tube. Metal foams have various advantages for use as filter media and substrates in internal combustion engines [38,39]. First, metal foams of various pore sizes, from 450 to 1200 micron, can be produced and the resulting porosities range around 85%-95%.…”