Comparative tribological investigation of bio-lubricant formulated from a non-edible oil source (Jatropha oil)

•The wear rate for 10% Jatropha oil added biolubricants were almost identical with base lubricant.•Higher coefficient of friction leads to increase the wear.•At the beginning of the test rate of wear as well as rise in temperature were high.•In terms of viscosity, almost all bio-lubricants met the ISO viscosity grade requirement.•The COF of the steel ball specimens was reduced with the addition of JO in the base lubricant.

The investigation of lubricated friction and wear is an extended study. This paper outlines the tribological characteristics of Jatropha oil (JO) contaminated bio-lubricant by using Cygnus wear and Four-ball tribo testing machines. To formulate the bio-lubricants, 10–50% by volume of Jatropha oil were blended with the base lubricant SAE 40. Experimental results showed that the lubrication regime that occurred during the test was boundary lubrication while the main wear mechanisms were abrasive and the adhesive wear. During Cygnus wear testing, the lowest wear was found with the addition of 10% JO, and above 20% contamination, the wear rate was increased considerably. The addition of Jatropha oil in the base lubricant acted as a very good lubricant additive which reduced the friction and wear scar diameter of maximum 34% and 29%, respectively during the tribo test. The application of 10% bio-lubricant in the automotive engine will enhance the mechanical efficiency and take part to reduce the dependency on petroleum oil as well.