Effect of Fuels on Compression Ignition Engine Particle Number and Mass Emissions and DPF Filtration Efficiency

As part of decarbonization, alternative fuels are likely to be used in compression ignition internal combustion engines as a substitute for diesel fuel. There have been many studies on the effect of these alternative fuels on emissions and catalytic aftertreatment systems. Past research has reported lower particulate matter (PM) and higher oxides of nitrogen (NOx) with biofuels. However, there are limited studies on the effect of PM on the performance of diesel particulate filters (DPFs), especially in its effectiveness of PM filtration. PM emissions from four (4) types of fuels and five (5) of their blends, a total of nine fuels, were investigated using PM2.5 mass, soot mass, solid particle number (> 10 nm SPN10 and > 23 nm SPN23)and size distribution (6 nm to 560 nm) measurements at inlet and outlet of a DPF. The PM emissions were measured over a non-road regulatory cycle sequence consisting of five (5) non-road transient cycles (NRTCs) and five (5) non-road steady-state cycles (NRSCs). PM Measurements were used to understand the impact of fuel properties on DPF-In and -Out concentrations and filtration efficiency. . While the data showed an expected trend for the DPF-In emissions, it showed an opposite trend for the DPF-Out Ultra-low sulfur diesel (ULSD) had the highest concentrations and biodiesels had the lowest for DPF-In, but the opposite was observed for DPF-Out. Presence of oxygen in the fuel correlated with lower DPF-In particulate concentrations. However, the DPF-Out emissions were a function of DPF soot loading. Higher soot loading from fuels with higher DPF-In PM resulted in lower DPF-Out emissions and a better filtration efficiency This work suggests that diesel engines intended to run on various biofuels and alternative fuels may require careful consideration of the appropriate DPF type, with attention to the specific characteristics of each fuel.