Lubricity Survey of Low–Level Biodiesel Fuel Additives Using the “Munson ROCLE” Bench Test

The precision Munson Roller on Cylinder Lubricity Evaluator (M–ROCLE) was used to tribologically evaluate biodiesel additized winter fuel in the laboratory. Eleven biodiesel esters and oil derivatives were prepared, and blended at a 1vol% concentration with a low sulfur, unadditized reference winter diesel fuel. These vegetable–based additives were compared using wear scar areas, coefficients of friction and dimensionless Lubricity Numbers. All of the 1vol% biodiesel blends raised the Lubricity Number of the reference fuel from 0.813 to above the pass/fail value of 1.0. The top 2 lubricity enhancing additives, canola methyl ester and a canola oil derivative, were explored further with tests at treat rates below 1vol% and both were found to be effective at a 0.1vol% concentration. The overall Lubricity Number coefficient of variation of the Munson ROCLE test data was 5.4%, indicating reliable discrimination between fuel samples.