Effects of a Catalyzed Particulate Filter on Emissions from a Diesel Engine: Chemical Characterization Data and Particulate Emissions Measured with Thermal Optical and Gravimetric Methods 2003-01-0049

A wide range of emissions were characterized from a heavy-duty diesel engine operated on conventional low sulfur (∼375 ppm) fuel, equipped with manually controlled EGR and a catalyzed particulate filter (CPF). The effect of the CPF and engine load was studied, along with a comparison of results between the gravimetric and thermal optical methods (TOM) for determining diesel particulate levels. Data were obtained from four of the EPA old 13 mode test cycle steady-state operating conditions, i.e., Modes 11, 10, 9, and 8 using a 1995 Cummins M11-330E engine with a Corning EX-80 cordierite particulate filter, coated with a platinum catalyst (5 g/ft³). Emission characterization results presented in this paper include: total particulate matter (TPM), comprised of solids (SOL), soluble organic fraction (SOF), and sulfates (SO₄) that were determined gravimetrically; semi-volatile organic compounds (XOC), and total carbon (TC), comprised of elemental and organic carbon (EC and OC, respectively), that were obtained using the TOM. Raw and dilute exhaust measurements were performed to compare carbonaceous particulate matter (CPM) concentrations in the raw exhaust and SOL concentrations in the dilute exhaust. Significant reductions were typically observed across the CPF at all operating conditions for most emissions, including TPM, SOL, SOF, XOC, HC, CO, NO_x, and particle volume distributions. Trace metal emissions also showed reductions across the CPF. The metals comprised less than 1% of the TPM. Relatively good agreement was observed between the gravimetric method and the TOM. Significant increases in sulfate emissions were observed at two of the operating conditions (Mode 11 and 8), which was in agreement with the particle number increases across the CPF. Carbonaceous particulate matter (CPM) collected in the raw exhaust tended to be higher for upstream experiments than the SOL in the dilute exhaust at the high load conditions and tended to be in better agreement at the low load conditions. TPM, SOL, TC, EC, OC, NO_x, and CO₂ tended to increase with increasing load, while SOF, XOC, and gas phase HCs tended to decrease with increasing load.