Lubricity

Blending biodiesel into petroleum diesel even at low levels can improve the lubricity of diesel fuel (i.e., reduce wear scar diameter). As little as 0.25% biodiesel can significantly improve lubricity. Figure 10 shows results of lubricity testing using the HFRR, the test used to determine if diesel fuels meet the ASTM lubricity requirement of a maximum 520-micron wear scar diameter. The exact blending level required to achieve adequate lubricity depends on the properties of the conventional diesel. Preliminary evidence suggests that 2% biodiesel almost always imparts adequate lubricity.