**1. Introduction**

The greenhouse gases, the main cause of global warming, emitted mostly by mobile sources that use, petroleum diesel fuel, which emits toxic gas and known as carcinogenic. On the other hand, these mobile sources generate large amounts of used lubricating oil, considered as hazardous waste, which affect human health and the environment "We only have 10–12 years to save ourselves from the new limit of 1.5°C of average temperature increase (not 2°C as was believed), which would be the point of no return" IPCC 2018 [1]. "Lyon (France), June 12, 2012 (AIIC/WHO)—After a week of the meeting of international experts, the International Agency for Research on Cancer (AIIC), which is part of the World Health Organization (WHO), announced this on June 12, that the exhaust fumes from diesel engines have been classified as carcinogenic to humans (Group 1), based on sufficient scientific evidence showing that such exposure is associated with an increased risk of lung cancer" [2]. According to the Basel Convention, ratified and adopted in Colombia through Law 253 of 1996, used oils of automotive and industrial origin are classified as a hazardous waste of mineral oils. Their dangerous characteristics vary according to the processes or equipment in which they have been used; Among its possible dangerous components are lead, chlorine, barium, magnesium, zinc, phosphorus, chromium, nickel, aluminum, copper, tin, sulfur, and polynuclear aromatic hydrocarbons, among others; others, which if released or mishandled may have immediate adverse effects or retarded in the environment. This is due to the bioaccumulation and its toxic effects on biotic systems, which effect human health and natural resources [3]. Undoubtedly, the real solution is electrical energy in all its possibilities, from renewable sources, but in the meantime, these energies, as in the case at hand, biodiesel (B100), obliges as soon as possible to break paradigms and take risks with bold, alternative, or unconventional solution proposals that facilitate an efficient and safe transition, from fossil fuels, through biofuels and biolubricants, toward totally clean energies.

It is not unreasonable then to propose a new use for B100, as a biolubricant; its physicochemical characteristics are very close not only to fossil diesel fuel but also to the physicochemical characteristics of commercial mineral and synthetic lubricants.

The review of similar characteristics of B100 with commercial lubricants refers to the direct use of B100 inside the crankcase, performing the integral function of engine lubrication. This procedure can be adapted to virtually any modern diesel engine, as any modern diesel engine would be capable of using B100; but it also applies to all diesel engines capable of using mixtures (B10, B20, B50, etc.), complementing it with an alternate mechanism, arranged in the procedure to make the mixtures (B100 + petroleum diesel), before entering the injection system of fuel, and after the passage of B100 (100% pure), through the crankcase in its role as a lubricant. It is also possible to use B100 as a lubricant for spark-ignition engines.

This new function of B100 as biolubricant means that the use of commercial mineral and/or synthetic oils in diesel engines disappears; motor oil disappears into the maintenance budget for vehicles and transport fleets, which would be limited to the normal change of filters. At the same time, the environmental contamination caused by used oils also disappears. In the procedure, immediately after the function of B100 as biolubricant, the following function of B100 as biofuel, reduces about 80% of greenhouse gas emissions, thus contributing significantly to the reduction of global warming.

The process is based on the physicochemical characteristics of B100, which in principle are key to what is required, such as a high boiling point; low vapor pressure; flashpoint higher than 170°C (for palm biodiesel), much higher than that of diesel (64°C); a density of about 0.88 g/cm<sup>3</sup> ; viscosity at 40°C of 4.5 mm2 /S; lubricity of 6000 g BOCLE [4].

The biodiesel produced from pre-esterified Colombian palm oil meets the technical specifications required by European Standard 14214 for the properties evaluated.

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

Biodiesel produced stands out for its high chemical stability (oxidation stability). The main quality deficiency of biodiesel from palm oil is its low value in determining the cold filter plugging point (POFF. 10–12°C.), which would not greatly affect tropical or during the summer season [5].
