Characterization of a Lightly Loaded Underfloor Catalyzed Gasoline Particulate Filter in a Turbocharged Light Duty Truck

A test program to characterize the benefits and challenges of applying a European series production catalyzed gasoline particulate filter (GPF) to a U.S. Tier 2 turbocharged light duty truck (3.5L Ecoboost Ford F150) in the underfloor location was initiated at the U.S. Environmental Protection Agency. The turbos and underfloor location keep the GPF relatively cool and minimize passive regeneration relative to other configurations. This study characterizes the relatively cool GPF in a lightly loaded state, approximately 0.1 to 0.4 g/L of soot loading, using four test cycles: 60 mph steady state, 4-phase FTP, HWFET, and US06. Measurements include GPF temperature, soot loading, GPF pressure drop, brake thermal efficiency (BTE), CO2, PM mass, elemental carbon (EC), filter-collected organic carbon (OC), CO, THC, and NOx emissions. The lightly loaded underfloor GPF achieves 85–99% reduction in PM mass, 98.5–100.0% reduction in EC, and 65–91% reduction in filter-collected OC, depending on test cycle. The smallest reductions in PM and EC occur in the US06 cycle due to mild GPF regeneration caused by GPF inlet temperature exceeding 500°C. EC dominates filter-collected OC without a GPF, while OC dominates EC with a GPF. Composite cycle CO, THC, and NOx emissions are reduced by the washcoat on the GPF but the low temperature location of the GPF does not make best use of the catalyzed washcoat. Cycle average pressure drop across the GPF ranged from 1.25 kPa in the 4-phase FTP to 4.64 kPa in the US06 but did not affect BTE or CO2 emissions in a measurable way in any test cycle.