Adaptation of both oil based fuel and engine technologies are key enablers to reduce CO2 footprint as well as pollutant emissions. Recent work has demonstrated the potential of gasoline-like fuels to reduce NOX and particulate emissions when used in compression ignition engines. In addition, properties of naphtha produced directly from the atmospheric crude oil distillation process in a refinery offer significant CO2 benefits.
When introducing such innovative fuel and engine, after-treatment investigations are mandatory to meet pollutant regulations. In that respect, this work focuses on investigating structure and properties of the particulates produced with naphtha fuel to validate Diesel Particulate Filter (DPF) design requirements. First, soot mass measurement techniques are detailed. Then, characterization of soot is performed through DPF pressure drop, soot oxidation rates with and without Fuel Borne Catalyst (FBC), composition & structure analysis. Lastly, particulate size distribution is assessed for different operating conditions.
Results show that regardless of the fuel, FBC use has the same impact on soot oxidation. A slightly lower oxidation rate of naphtha soot was observed, most likely linked to oxygenated species present in Diesel fuel. Lastly, engine combustion process, more than fuel composition seems to be the most important factor for particulates size distribution.
Finally, differences between naphtha and conventional Diesel soot are very low or negligible for all the parameters investigated in this work. Based on these results, DPF design rules and standards usually used with Diesel fuel could be transferred for a naphtha based fuel powertrain application.
