Particle size distributions from a city bus fuelled with ethanol-biodiesel-diesel fuel blends

The use of oxygenated fuels has potential to reduce the greenhouse gases and the regulated pollutant emissions from diesel engines. Apart from particulate matter and NOx emissions, the study of particle concentration and its size distribution emitted by diesel engines is gaining attention due to the harmful effects on the environment and human health. In this work, particle size distributions (PSDs) from the exhaust gas of a city bus working in real driving conditions have been measured using three different fuel blends: petroleum diesel used as reference fuel, a binary fuel blend of 7.7% v/v ethanol on diesel fuel (denoted as ED) and a ternary fuel blend (denoted as EBD) of ethanol, biodiesel and diesel fuels with 10% v/v of ethanol on a binary B30 fuel blend (30% v/v of soybean biodiesel on pure diesel fuel). For measuring the PSD, a city bus was equipped with a rotating disk diluter coupled to a dilution air thermal conditioner. The diluted gas was driven to a TSI Engine Exhaust Particle Sizer spectrometer. The main objective of this work was to evaluate the effect of the fuel on the main statistical parameters of PSD (geometric mean diameter and total concentration) during acceleration transitions in real vehicle driving operation. Compared to diesel fuel, the results showed a great reduction of particle concentration when both fuel blends were used, although the relative differences depended on the transition studied.