**2. Consideration of biodiesel (B100) as biolubricant**

Biolubricants have several advantages compared to mineral-based lubricants:


These basic physicochemical characteristics are what we must find in Biodiesel to consider it as a biolubricant. The higher lubricity of biolubricants results in less friction, and a higher viscosity index has more efficient heat transfer. In addition, due to their better adherence to metal surfaces, biolubricants, being polar substances, produce more resistant lubricating films, in any type of lubrication.

The arguments (physical and chemical aspects) to consider B100 as a biolubricant:


the Noack volatility test reveals the evaporation loss at high temperatures of the oil's lighter molecules and additives. Depending on the method, a quantity of sample is placed in a crucible or reaction flask and heated at 250°C with constant airflow for 60 min. The comparison of the weight before and after the test will determine the loss by evaporation. Evaporation losses can also result in a change in oil properties, as additives can evaporate during the volatilization process. As the lighter molecules "burn" or evaporate, the heavier molecules remain, causing a change in fluid viscosity [6].


*Bio-Circular Engine: Simultaneous and Successive Use of BioDiesel as Bio-Lubricant… DOI: http://dx.doi.org/10.5772/intechopen.103663*

10.The thermal stability stands out, with a thermal reflectance value of 99% (above the thermal reflectance of aluminum of 93%), which allows it to carry out very efficient thermal management of cooling inside the engine, as a contour element.

**Figure 1** shows the oil temperature gauge of a truck, for a maximum expected temperature of 300°F (148.89°C), which is below the spark point of palm biodiesel (180°C. Bio-D Colombia).

Thermal requirement for diesel engine oil in normal operation:

	- 11. Other considerations in favor of B100: The main effects of motor oil contamination, such as dilution with fuel, thermal degradation of the lubricant base, and contamination occur, as has been said, largely as a result of the mentioned blow-bay phenomenon; but the passage of substances through the piston and cylinder rings does not only occur in the direction of the crankcase but also known that no matter how new the engine is, there will always be a passage of lubricating oil from the crankcase to the combustion chamber because the oil will always be circulating (even if it is in a minimum amount) through the spaces between the rings and the grooves, the pistons and cylinder walls which also require lubrication. These minimum amounts of oil grow over kilometers and time, affecting to a greater or lesser extent the ignition process of the mixture, the quality of combustion, and the quality of emissions, as well as generating greater contamination by volatile compounds generated by the combustion of gases and heavy chemical elements from oil additives and their mineral bases.

**Figure 1.** *Temperature data of some brands of commercial motors.*
