The relation between lubricity and electrical properties of low sulfur diesel and diesel/biodiesel blends

This work evaluates the relation between lubricity and electrical impedance properties of a series of diesel fuel samples with different sulfur content and low sulfur diesel/biodiesel blends. Diesel samples as well as the diesel/biodiesel blends were characterized by standard experimental techniques. In the case of diesel samples, density, nitrogen content and viscosity demonstrate a linear tendency with the composition. Lubricity, measured as WSD (wear scar diameter) does not follow linear behavior with the composition. However, a linear correlation between electrical resistivity and WSD−1 was observed which allow the determination of lubricity in diesel mixtures. The addition of 1–10% biodiesel does not change significantly the density and viscosity of the blends. No linear relation of resistivity to lubricity was established. The important effect of lubricity enhancement with addition of approximately only 1% biodiesel was obtained. The relation between lubricity or electrical resistivity and biodiesel addition is quantitatively described by exponential function.