Passive Soot Regeneration Observations on a GPF-equipped vehicle for PM exhaust emission control.

The gasoline particulate filter (GPF) will be a common technology adopted by EPA Tier4 emission compliant vehicles, starting as early as model year 2017 in North America. For those Tier-4 compliant gasoline-powered powertrains, their GPF solutions will require that the captured soot can be safely removed through passive oxidation. This clean-out process is driven by occasional fuel-cut events, such as engine motoring, which would provide an excess of oxygen in the exhaust gas flow to the hot, soot-loaded GPF. Here, a study has been conducted where a modern vehicle with a 3L engine displacement was upfitted with appropriately sized GPFs for soot capture in the dual-bank exhaust line. These GPFs were weighed to track their soot-load trends between representative real-world driving routes, where sensor data and ECU parameters were recorded. Thus, characterization of the passive soot regeneration process in the GPF was linked to the preceding exposure of gaseous flow temperatures, oxygen-availability, and other exhaust flow behaviors. An understanding of the operating levers to the passive regeneration process will help OEM system designers and engine calibrators and create a durable operating environment for future GPF applications.