**4. Bio-lubricant biodiesel (B100) as a new oil for 4-stroke internal combustion engines, 100% biodiesel**

This statement includes the formulation of Biolubricants for 4-stroke internal combustion engines, using as bio-lubricant base, biodiesel (B100), hydro-biodiesel, and/or other products for the same function from biomass. As an additive, biodiesel (B100), hydro-biodiesel, and/or other products for the same function from biomass obtained from raw materials other than the biolubricant base, with physical–chemical characteristics to enhance the properties of the base and/or introduce new properties, always obtaining B100 in the end, this being a suitable biolubricant, which guarantees the superior protection and durability required by engine manufacturers, without prejudice to the fact that only the biolubricant base (biodiesel, hydro-biodiesel, others) fulfill the double function of biolubricant and/or biofuel; and notwithstanding that any crude or processed vegetable or animal oil may be used as biolubricant base oil or as an additive. The physicochemical characteristics of B100 as a new biolubricant for 4T engines correspond to those that are representative of high-quality commercial oils, required by manufacturers, and regulated by international regulations (ISO, SAE, EN, ASTM, API, etc.).

In the case of the formulation described here of B100 as a biolubricant, it refers to combining the characteristics of biodiesel obtained from different types of fatty acids, for example:

Saturated fatty acids: such as some used edible oils or animal fats that, when transformed into biodiesel, have good characteristics for high temperatures.

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

Unsaturated fatty acids: such as rapeseed, soybean, sunflower, castor oil, jatropa curcas, and others, when transformed into biodiesel, have good properties for low temperatures.

Fatty acids with virtually the same proportion of saturated and unsaturated: such as Colombian palm oil, which contains an approximate proportion of 50% saturated and 50% unsaturated fatty acids, when transformed into biodiesel, present virtually a sum of the good properties of the two types of fatty acids above, that is, relatively good characteristics for high temperatures and low temperatures.

In some cases, such as Colombian palm oil, the main deficiency is its cloud point of 10–12°C (which would not be a problem in tropical countries or in the summer season). This deficiency can be corrected by adding (as an additive) biodiesel (B100) obtained from rapeseed, soybean, sunflower, canola, castor, or jatropha oil, which have excellent cold characteristics due to the high degree of unsaturation, with cloud points below between 0°C and –30°C and even lower in some cases.

B100 or 100% biodiesel, as a biolubricant, is the only fluid known and indicated for the total performance of the procedure indicated here for 4T diesel engines, with Bio-Circular technology, in stage 1 as biolubricant and stage 2 as bio-fuel.

Based on the fact that a 4-stroke (compression-ignition) diesel engine is mechanically similar to a 4-stroke (spark-ignition) gasoline engine, except for the fuel delivery and ignition systems, as well as the type of fuel, and then of carrying out driving tests in a passenger vehicle with a 4T gasoline engine, using B100 as a lubricant (only as a lubricant), the optimal operation of the engine has been verified without presenting damage or wear outside the norm. Consequently, B100 can be used as a lubricating oil for 4T gasoline engines (spark ignition) and in general, for engines with a sump or engine oil tank.

In no case can B100 be used as fuel, in a gasoline engine (spark ignition), because B100 require very high pressures inside the combustion chamber for their self-ignition; compression ratio between 17:1 and 24:1 for 4T diesel engines; while the compression ratios for a gasoline engine is usually between 9:1 and 12:1.

This new function of B100 as lubricating oil for 4T engines will allow not only significant savings in scheduled engine oil changes; it means that this item disappears forever within the maintenance budget for vehicles, transport fleets, industrial equipment, limiting it only to the normal change of filters but environmental pollution due to the dumping of used oils into the environment (soil, air, water) also disappears.

All the execution and elements of the Bio-Circular Engine are developed under sufficiently documented and proven procedures and techniques; without prejudice to the fact that it can be executed under the application of new or similar technologies, or even without the application of the technologies described herein.
