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/cm³; 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. 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].

2. Consideration of biodiesel (B100) as biolubricant

Biolubricants have several advantages compared to mineral-based lubricants:

High degree of biodegradability.
Low toxicity to humans and aquatic organisms.
Good lubricating properties.
High viscosity index.
High flashpoint.
Good adhesion to metal surfaces.

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:

High Flash or Spark Point of Palma B100: 160°C: Available ASTM tests include ASTM D56, Tag Closed Cup Flash Point, used for viscosities below 5.5 cSt at 40°C, as well as for viscosities below 9.5 cSt at 25°C and flashpoints below 93°C. ASTM D93, Pensky-Martens Closed Cup Flash Point is used for petroleum products with a temperature range from 40 to 360°C and biodiesel with a temperature range from 60 to 190°C. Flashpoint is also very useful in used oil analysis to detect dilution with fuel, thermal degradation of the base oil, and contamination [6]. These three previous aspects would not apply in the case of B100 as a lubricant.
Kinematic viscosity of Palma B100: 4.71 cSt at 40°C; 2.25cSt at 100°C.
Low Volatility of B100 from Palma: Flat distillation curve; with 309°C initial boiling point, 50% recovered temperature of 321°C, and 338°C final boiling point. This indicates that the fatty acid methyl esters that makeup palm biodiesel do not have very high differences in their boiling points, while petroleum derivatives have a wide variety of hydrocarbons with different volatilities [7]. Volatilization is a term used to describe the “boiling off” of lighter molecules in fluids. It is closely related to oil consumption in car engines. The test simulates the reaction of oil to internal temperatures found in the ring/piston/cylinder area of internal combustion engines. Known as ASTM D5800, 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].
Low phosphorus content of B100: 1.26 mg/kg. + ASTM 6751 Standard: Max. 10 mg/kg. The Selby-Noack volatility test uses a noble metal heater; eliminates the need for Wood’s metal and collects the evaporated material for further analysis. This is particularly useful for identifying elements such as phosphorus, which are known to lead to premature failure of catalytic systems [6].
Lubricity; B100 as Newtonian Fluid: The shear rate is proportional to the shear stress, a typical characteristic of lubricating oils [7].
Lubricity; B100 as Polar Substance: Excellent adherence to metal surfaces. The metal is considered as an electrostatic surface, where there is an electronic cloud, therefore, it is negatively charged, attracting polar substances such as esters. This attraction occurs through the carbon atom of the ester carbonyl (C = O), which has a charge density δ(+) [8, 9, 10, 11, 12]. The molecules are attached to the surface under the mechanism of physical adsorption [10, 11]. The lubricating film is formed by the absorption on the metallic surface of molecules of polar substances. When compatibility of forces occurs, an attraction occurs between the absorbent and the substance to be adsorbed, resulting in the fixation of the molecules of the substance on the surface of the solid. For this type of adsorption, we can have several layers of adsorbed molecules [10, 11].
Blow By; harmless phenomenon for B100. The problem of contamination of the lubricant, caused by fuel entering the crankcase through the cylinders and piston rings (Blow-By), is eliminated. Petroleum diesel fuel (fuel dilution), depletes additives and introduces sulfur and aromatic compounds into the motor oil, affecting viscosity. This will never happen with B100 because its runoff to the crankcase due to Blow By will be mixed with the same B100 that will be in its first stage or function as engine lubricant; also, because the B100 is free of the polluting elements.
Water content in B100 from Palma: 380 mg/kg. + ASTM 6751 Standard: Max. 500 mg/kg. Water has a devastating effect on oil and lubricated parts because it leads to rust and corrosion, respectively. In oils with anti-wear additives based on Zinc Dithiophosphate (ZDDP), the water reacts with them and gives rise to the formation of sulfuric acid, eliminating the limited lubricating film. Similarly, this will never happen with B100 because it is free of additives.
Its prolonged oxidation stability of 26 h (minimum 3 h for the ASTM 6751-S500 standard; minimum 6 h for the EN 14214 standard), maintains the chemical stability of B100 for a longer time in optimal working conditions, compared to fossil mineral oils.
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).

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

Thermal requirement for diesel engine oil in normal operation:

190–220°F (88–104°C) for Caterpillar.
180–225°F (82–107°C) for Cummins.
200°230°F (93–110°C) for Detroit Diesel.
181–203°F (83–95°C) for Mercedes-Benz

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.

3. Comparison between synthetic ESTER and B100 or FAME (fatty acid methyl Ester)

3.1 Synthetic Ester

Esters are the result of the chemical reaction of an organic acid and an alcohol. Acid with two carboxyl groups (a functional group characteristic of organic acids) is called a diacid and the product of its reaction with alcohol is called diester. The alcohol that has more than one hydroxyl group (functional group characteristic of alcohols) is called a polyol. The product of the reaction of an organic acid with a polyol is called a polyol ester [13].

Diester These are mostly used among synthetic esters. They are more stable to oxidation and heat than hydrocarbons, beginning to decompose at 200°C. They contain two carboxyl, (C = 0) responsible for the characteristic of the polar substance (Figure 2).

3.2 B100 or Fame (fatty acid methyl Ester)

They contain three carboxyl (C = 0), responsible for the characteristic of the polar substance. These various adsorbed layers of biodiesel molecules (3 esters, 3(c = o)), constitute the key to the performance of B100 as a biolubricant, which allows it to withstand high pressures and high shear rate (HPHS), in any lubrication regimen and engine workload (Figure 3).

Figure 3.
Triester: (biodiesel). Transesterification process.

When machine surfaces interact with higher pressures and temperatures, additives mitigate the typical effects of metal-to-metal contact (wear) by creating initial molecular layers on the machine surface that are more ductile. These friction control layers directly reduce shear resistance during contact and are sacrificed.

The first layers can mitigate friction by allowing the weaker molecular bonds in the lubricant to be released with less force compared to the strong bonds that result from film boundary conditions due to metal-to-metal contact of surface asperities. The formation of low shear strength films is also affected by the type of base oil and the metallurgy of the surfaces.

There are three types of lubricant additives that help reduce this friction and control wear: friction modifiers, anti-wear additives, and extreme pressure additives [14].

In this tribological scenario, the main characteristic of B100 as biolubricant becomes important (B100 is Tri-Ester). This means that B100 has an adsorption intermolecular force 50% higher than commercial fossil synthetic ester bases (Di-Ester). This condition of intermolecular power superiority translates into a constant presence of the lubricant film, even in extreme lubrication conditions such as those mentioned here.

It is also important to highlight that most additives for motor oils, for the different functions required (detergents, dispersants, anti-wear, anti-rust, high pressure, etc.), are polar substances (eg. ZDDP); the vast majority are also based on sulfur, phosphorus, zinc, and others that are highly polluting the environment, in addition to triggering chemical processes that deteriorate the quality of the oils inside the engines.

3.2.1 Fatty acid composition

Table 1 shows the composition of fatty acids, in the central column, it is shown in yellow, half corresponds to saturated fatty acids and the other half to unsaturated fatty acids. This represents the connection key that, from the concept of biofuel, brings us closer to the concepts of biolubricants.

Composicion de acidos grasos
Acidos Grasps		Aceite de Palma		Aceite de Palmiste
Caprico	C10:0			3.7
La aim	C12:0	0.2		48.3	Acidos
Miriam	C14:0	1.1		15.8	la Lin cos
PaImfti co	C18:0	44	50%	7.8
Esteasico	C18:0	4.5	Saturados	2
01Aim	Cl	39.2	50%	15.1
Lindeico	C18:2	10.1	Insalura dos	2.7

Table 1.

Fatty acid composition of palm oil.

The unsaturated compounds have an iodine value close to 85 g I/100 g of sample, while the saturated ones have an almost zero value. Unsaturated oils have a low viscosity and a lower pour point than their saturated counterparts.

Cold properties are strongly influenced by the degree of unsaturation; unsaturated compounds remain liquid at temperatures below 0°C, while saturated compounds are solid at room temperature. Saturated compounds have higher oxidative stability due to the absence of double bonds, but poor cold properties. Only unsaturated compounds are suitable for use as lubricants, but they can only be used under operating conditions that do not require high oxidative stability [15].

3.3 Common characteristics

Some characteristics between diesters (synthetics) and triester (B100). Diesters and triester have natural properties of lubricity and high detergency and dispersance, so they receive the name of clean operating lubricants. Their thermal stability allows them to work up to 180°C. They can operate at low temperatures since its freezing points are between –50 and –60°C (only some B100s). The viscosity index is high, close to 140. They have low volatility, high solvency for both additives and tanks, cleaning the sludge left previously; they tend to dissolve varnishes and lacquers. Soften the elastomers of the seals, therefore, it is recommended to use with these oils, viton seals and medium to high nitrile buna N. They are compatible with mineral oils and are biodegradable [12].

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.

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.

5. B100 and “Bio-circular engine”

The “Bio-Circular Engine” that results from considering the possibility of using B100, not only as a biofuel but also as biolubricant, once its properties have been determined, we can define it as: “Procedure, apparatus, bio-lubricant and bio-fuel for simultaneous use of b100 with dual function in diesel engines”. But it can also be expressed as follows in a more descriptive way as: “Procedure and apparatus for simultaneous use of b100, with double function, in diesel engines: stage 1, as bio-lubricant and stage 2, as bio-fuel”.

The Bio-Circular Engine is related to the use of biodiesel in 4T diesel engines (vehicular, commercial, industrial, railway, river, sea, aviation, etc.), but also applicable to all kinds of internal combustion engine which run a crankcase (oil inside the engine), from B100 or pure biodiesel to different mixtures (B10, B20, B50, etc.), to reduce polluting emissions from petroleum diesel. It is also related to the use of biodiesel (B100), with or without additives of organic origin, such as biolubricant, to avoid contamination of lubricating fossil oils used in internal combustion engines in general. It is also related to a procedure to make diesel engines work with biodiesel, in such a way that it simultaneously and successively fulfills the two functions: as biolubricant in stage 1, and as biofuel in stage 2; either with B100 or with the required diesel-biodiesel mixture. The application or use of any type of procedure, apparatus, or device that uses biodiesel to lubricate the engine and once this task is carried out, is successively and continuously taken to the injection system to be used as fuel is unknown. Currently, it is very common to use biodiesel obtained from different oilseeds (with different characteristics, depending on the geographical region where they are grown), to be used as fuel, in a pure form (B100 or 100% Biodiesel); but also mixed with petroleum diesel (B10, B20, B50, etc.). The first aspect of the new Bio-Circular Engine, a procedure applicable to diesel engines is provided, certified to use biodiesel B100 (100% pure biodiesel.), but also certified for any percentage of mixture with mineral diesel fuel (B10, B20, B50, etc.); with double function, in two successive and/or simultaneous stages: In stage 1, B100 or pure biodiesel is conducted from the fuel tank to the crankcase or engine lubricant tank (previously filtered), where it will fulfill the first integral function as biolubricant. In stage 2,—successively and/or simultaneously—it is conducted from the same crankcase to the injection system of the diesel engine (previously filtered), where it will fulfill the second function, as biofuel. The complete process will be governed by the Control Unit (ECU), which will control the two successive and simultaneous stages, through the data obtained through specific sensors. This procedure can be adapted to virtually any modern diesel engine, as virtually any modern diesel engine would be capable of using B100. The second aspect of the Bio-Circular Engine consists of an apparatus or device to carry out the 2 stages of the aforementioned procedure, which is made-up of a series of electrical, electronic, and mechanical elements. These items include low- and high-pressure piping for the B100; electric pumps, pressure, temperature, level, flow sensors, etc.; filters; in some cases, radiator for the B100 just removed from the crankcase; electric cables; electronic control unit (ECU) and others, which when installed in 4T diesel engines and then interconnected with each other, will allow the supply of the B100 from the vehicle’s fuel tank, passing through the engine crankcase for its first function as biolubricant and from there direct it to the fuel injection pump and later to the injectors located in the cylinder head for its second function as biofuel. This general configuration of the device is designed for use with B100, in 4T diesel engines manufactured from the year 2000 onwards, as they were built with sealing materials and plastic elements (Viton), resistant to the detergent action of B100. It is included in the Bio-Circular Engine, a variation of the device, which in addition to being able to use B100, allows it to be installed in 4T diesel engines manufactured before the year 20,000 that have been refurbished to use biodiesel but for technical reasons or due to poor availability of B100 must add fossil diesel (B10, B20, B50, etc.). This addition of the fossil diesel is made after the B100 has performed its first lubrication function. Once extracted from the engine crankcase, it is taken through the duct corresponding to a new device where B100 duct and the fossil diesel duct converge, which arrives from its own totally independent tank and pipe, located in a place away from the fuel tank B100. For this variation of the original procedure and apparatus, some additional elements must be installed, such as, the mixing station and fuel percentage selection monitor, in addition to its interconnections with the ECU, which allows the use of at least B5–B100 (with this variation, operation with only B100 in the two stages is also planned; it is enough to suspend the supply of fossil diesel), which will guarantee that B100 will always be renewed in its function as a biolubricant inside the engine, to a lesser or greater degree flow rate, which will depend on the amount of B100 chosen on the selector provided for it. As mentioned earlier, the entire process will be governed by the ECU, which will control the two successive and simultaneous stages, using the data obtained through specific sensors. The third aspect of the Bio-Circular Engine, a biolubrican biodiesel (B100) A as a new oil for 4-stroke internal combustion engines, 100% biodiesel, which is the only fluid known and indicated for the total performance of the procedure and device characteristic of the Bio-Circular Engine; with all the required and recognized physicochemical characteristics of modern commercial synthetic oils, for its performance in 4T engines, composed entirely of 100% biodiesel (B100); the base is a B100 obtained from a certain raw material, to which one or more portions of other B100 of the same or different generation (including hydro-biodiesel) and the same or different raw materials are added, to enhance the properties of the base and/or introduce new properties, always obtaining B100 at the end. In exceptional cases, it is also possible to add some type of substance that improves some of its properties (eg cold flow). The main characteristics of B100 as a biolubricant may vary depending on the raw materials (rapeseed, soybean, sunflower, palm, animal fat, used vegetable oil, etc.) from which it is obtained; the most important ones are: B100 is a polar substance (all additives in commercial mineral and synthetic oils are polar substances). It is a triester (a commercial synthetic oil is a diester). It is a Newtonian fluid (shear rate proportional to shear stress). It forms layers of molecules with greater strength of adhesion to metals (3 carbonyls per molecule). The higher the effort and pressure, the higher the viscosity. Palm reduction of NO_x emissions due to saturated triglycerides (B100 from Colombian palm), greater thermal and chemical stability, no rust, no sludge, no deposits. There is no acidification of the lubricant due to the Blow-By phenomenon (passage of fuel through the piston rings towards the crankcase). High polar strength (3 carbonyls). Low viscosity (fuel saving). High detergency (impeccable cleaning). No carbon in carter. Does not require the use of toxic additives. It does not pollute water, air, and land. High flashpoint (>170°C; Colombian palm B100). Volatility >300°. Excellent antiwear protection in limit and elastohydrodynamic lubrication in cases of high pressure, load, and temperature.

5.1 B100 and “bio-circular engine” the best way to execute the procedure, for the case of only for B100 in the 2 stages

Figure 5, (only for B100 in the 2 stages); shows all the elements for the use of B100 in both stages and throughout the procedure; provides the schematic of an internal combustion engine with the complete schematic drawing of the apparatus or device, with all the components arranged to enhance said procedure, where the conduction of the B100 can be observed, from the fuel tank to the Carter or engine oil tank, so that it performs the first function, as biolubricant (stage 1); Next, and on the opposite side of the engine, we can see the elements designed to extract the B100 from the Carter, drive it through the injection system to the injectors located in the cylinder heads, so that it performs the second function, such as biofuel (stage 2). The entire procedure will be governed by the ECU.

In Figure 6, (only for B100 in the 2 stages); You can see the conduction of the B100, by means of the electric pump (9) from the fuel tank (8), passing through the filter (7) to the Carter or engine oil tank, so that it performs the first function, such as biolubricant (stage 1); the flow and level controller (6) ensures the constant supply of B100 to the Carter, keeping it at the appropriate level line (horizontal intermittent double line), in such a way that the B100 fulfills its function as biolubricant, for a time t, which is determined by the constant flow of B100 to the fuel injection system (B100). Note: The residence or service time (t) of B100 inside the engine as a lubricant is determined by the fuel consumption of the Bio-Circular engine; for this, it provides that the transit of the B100 from the fuel tank (8), passing through the engine crankcase, until reaching the injectors (10) in the cylinder heads, is continuous; consequently, the volume of B100 that passes through said engine crankcase is exactly that consumed by the same engine in its internal combustion process, either as a function of the operating time and/or the distance traveled and/or the work performed. We will take as an example a vehicle with a 12,000 CC four-stroke (4T) diesel engine; 287 Kw; crankcase capacity of 40 l of lubricating oil and fuel consumption of 5 km/4 l. With the previous data, we know that approximately every 50 km of travel, it consumes 40 l of fuel (B100), which is the capacity of the crankcase, with which, for the case of this example, we can affirm the following: Every 50 km of travel, 40 l of B100 pass through the engine crankcase in its stage 1, as biolubricant. Every 50 km of travel, virtually all the 40 l of lubricating fluid (B100) would be renewed. Every 50 km of travel, virtually a complete change of engine lubricating oil would be done, at no additional cost. (Normally it is done every 15,000 km). Assuming that the same vehicle in the example moves at an average speed of 50 km/h, a complete change of lubricating oil would be done virtually every 1 h. From the conditions of the previous point, it can be deduced that every 6 min, 4 l of B100 would be entering the engine crankcase, that is, 1 l every 1.5 min. With the previous example, which takes real data from driving and normal operating conditions, it can be stated that biodiesel (B100) in its transit through the interior of the engine, in its first function as biolubricant (stage 1), at an average of 1 l every 1.5 min, can keep its physicochemical characteristics unchanged, so that once extracted from inside the engine, to continue its transit to the injection system, it will be in perfect condition for its second function as biofuel. (stage 2). Once B100 has passed through the interior of the engine (crankcase) in its biolubricant function, it is extracted from the crankcase through a duct (5), provided with a pre-filtering element, located at a certain level height, to guarantee the permanence of B100 inside the engine, if the supply of B100 from the fuel tank is suspended. Such level corresponds to the original level of the lubricant preset by the manufacturer; (END of stage 1). (START of stage 2); the conduit (5) is directly connected to the electric pump (4) in charge of sending the B100, already in its second function as biofuel, to the injection pump (2), which previously passed through the filtering station (3) (in some cases also cooled), to be conducted to the injector (10) located in the cylinder head where the B100 will be atomized inside the cylinder and ignited by the high compression of the piston and the help of the high cetane number (68 for the case of palm biodiesel) that will guarantee combustion with low levels of polluting emissions. (END of stage 2). All the execution and the elements of the present invention are interconnected and controlled by the ECU (1), notwithstanding that it can be executed under the application of new technologies or even without the application of the technologies described here; that is to say that, for the case of the example, it could eventually be possible to make use of the described procedure, using the elements installed at the factory, in the vehicles, to execute the same functions of the B100, not only in the conventional engine but also, the same, converted or adapted as a Bio-Circular Engine.

5.2 “Bio-circular engine” the best way to execute the procedure, for the case of B100 in stage 1 and B100-diesel blends in stage 2

Figure 7, (for B100 in stage 1 and B100-Diesel blends in stage 2); like Figure 5, it shows all the elements for the use of B100 in stage 1 as biolubricant; during stage 2, B100 is blended with fossil diesel. Additionally, the necessary elements for the realization of said mixtures are shown (B10, B20, B50, etc.), which includes from a diesel fuel tank, passing through the B100-diesel mixer, once mixed in the indicated proportion, it is carried out through the pressure system to the injectors in the realization of said mixtures are shown (B10, B20, B50, etc.), which includes from a diesel fuel tank, passing through the B100-diesel mixer, once mixed in the indicated proportion, it is carried out through the pressure system to the injectors in the engine cylinders. Before the passage of the B100 (100% pure) through the engine in its first function as a biolubricant, it is subsequently led to the mechanism arranged to make said biodiesel-diesel mixtures and finally to the injectors in the engine cylinders, where it will fulfill the second function as biofuel, in the mixture. The whole procedure will be governed by the ECU.

In Figure 8, (for B100 in stage 1 and B100-Diesel mixtures in stage 2), exactly the same operating scheme is executed as in Figure 6, until the end of the function of B100 as biolubricant (End of stage 1). For this case, in stage 2 (as biofuel) elements are added that have the task of mixing B100 or 100% pure biodiesel, with fossil diesel, to obtain mixtures technically known as B10, B20, B50, etc.; such mixtures are usually regulated by entities or states, according to environmental, economic, industrial requirements, among others. Returning to the case of Figure 6, at the point where the B100 passes through the filtering station (3) (and subsequent refrigeration if necessary), this B100 is led to the device (15), designed to make the mixture (B100 + fossil diesel); the fossil diesel for its part is conducted through the action of the electric pump (13), from the reservoir or tank (12), passing through the filtering station (14), to the aforementioned mixing element (15); proportions of B100 and petroleum diesel already mixed and previously selected on the display (16), is conducted to the high-pressure system or pump (2), to finally be transported to the injector (2), at the head of the cylinder. Also, for this case of Figure 8, all the implementation and elements of the present invention are interconnected and controlled by the ECU (1); without prejudice to the fact that it can be executed under the application of new technologies or even without the application of the technologies described here and even without their assistance. Note: It should be noted that both for the case of Figures 6 and 8, B100 that enters the Bio-Circular Engine crankcase in stage 1 (as biolubricant), is 100% pure biodiesel. For the case of Figure 4, B100 is only mixed with the fossil diesel, in stage 6, in the mixing element (15), consequently, there is no possibility that the fossil diesel enters the interior of the engine (carter and lubrication system), by the action of the process or device described in this new Bio-Circular Engine. For the case of Figure 8, the permanence of B100 as biolubricant inside the engine will not depend on the total fuel consumption as in the example of Figure 6; yes, it will depend on consumption, but depending on the percentage of B100 contained in the mixture (Biodiesel + fossil diesel). If we take the same conditions and engine data from the previous example and select a B20 mixture, that is, 20% biodiesel with 80% fossil diesel; with the data of the previous example in which the consumption of the engine is 5 km/4 l and the oil capacity of the crankcase is 40 l of lubricating oil, then every 50 km the entire lubricant would be renewed (40 l of B100). In the case of B20 (mixture of 20% biodiesel +80% fossil diesel) or (20% pure biodiesel in the fuel mixture), this pure biodiesel (B100) would then take five times longer to be completely renewed, that is, the total renewal would take 250 km of travel, to consume 40 l of B100 as a lubricant. If in the same way, we assume that the vehicle in the example moves at 50 km/h, then it would take 5 h for the 40 l of B100 to pass through the interior (crankcase) of the engine. This means that every hour 8 l of B100 would be renewed; that is, 4 l every 30 min; or what is the same, 1 l every 7.5 min. In conclusion, for the example that concerns us, we observe the difference between pure biodiesel B100 and a mixture of B20: With B100 (100% pure Biodiesel), the biolubricant in the crankcase is renewed at a flow rate of 1 l/1.5 min. With B20 (20% pure Biodiesel), the crankcase biolubricant is renewed at a flow rate of 1 l/7.5 min. Bearing in mind that in the case of the B20, the renewal time is five times greater, due to the fact that five times less biolubricant B100 circulates inside the engine (crankcase), it would only take 250 km to complete the total renewal. If we take into account that it is a vehicle with commercial characteristics, those 250 km would normally be traveled in 1 day or less, which will ensure the efficiency and stability of the physical–chemical characteristics of most biodiesels of different materials. Caution: All the execution and the elements of the present invention are interconnected and controlled by the ECU (1), notwithstanding that it can be executed under the application of new technologies or even without the application of the technologies described here; that is to say that, for the case of the example, it could be possible to make use of the described procedure, using the elements installed at the factory, in the vehicles, to execute the same functions of the B100, not only in the conventional engine but also, the same, converted or adapted as a Bio-Circular Engine.

Figure 4.
Bio-circular engine, conceptual diagram.

Figure 5.
Bio-circular engine, only for B100 in two stages.

Figure 6.
Bio-circular engine diagram, for the exclusive use of biodiesel (B100) in the 2 stages. Video 1 functional model, bio-circular diesel engine; https://bit.ly/3HgVXJi.

Figure 7.
Bio-circular engine, for B100 in stage 1 and B100-diesel blends in stage 2.

Figure 8.
Bio-circular engine diagram, for B100 in stage 1 and B100-diesel blends in stage 2.

6. Conclusions

Yes, it is possible to use biodiesel B100 as a biolubricant and once this first function has been fulfilled, it can fulfill its role as a biofuel.
The physicochemical characteristics of B100 remain intact due to the rapid transition from its function as a lubricant to its subsequent function as a fuel.
For the operation of the proposed procedure and apparatus, it is not necessary to add additive packages, since the natural characteristics of B100 are those that are usually obtained with said additive packages in lubricants of mineral origin; if necessary (low temperatures), it can be mixed (as an additive) with other biodiesel from unsaturated fatty acids (soy, sunflower oil, etc.), for such a requirement.
The rapid transit of the B100 guarantees a substantial improvement in internal cooling, as well as efficient cleaning, which translates into greater engine longevity.
The problem of contamination of the lubricant, is caused by the entry of fuel into the crankcase through the cylinders and piston rings (Blow-By). Fuel that depletes additives and introduces sulfur and aromatic compounds into the motor oil, affecting viscosity; this will never happen with B100, as it is free of harmful chemicals.
Water has a devastating effect on oil and lubricated parts by causing rust and corrosion, respectively. In oils with anti-wear additives based on zinc dithiophosphate (ZDDP), it reacts with them giving rise to the formation of sulfuric acid, which eliminates the boundary film. It will never happen with B100 because it is free of these additives.
Savings in maintenance and oil changes by the described procedure; do not repurchase motor oil.
B100 does not need to be added with any combustible substance (neither fossil nor biological).
B100, as a biolubricant, applies to all types of 4T (4-Stroke) internal combustion engines, whether they are vehicular, commercial, or industrial; including all diesel engines, but also all spark-ignition engines. Video 2; test vehicle spark-ignition engines; https://bit.ly/3HgVXJi
The Bio-Circular Engine described is a model that is inserted in the concept of the Circular Economy, in that it uses in one (1) single substance or product, for two (2) totally different functions (Bio-Lubricant + Bio-Fuel) successively and simultaneously.

Acknowledgments

To God, source of love, peace, and inspiration; to my parents Luz Alba and Pedro Pablo; to my beloved wife Blanca Aurora; to my dear daughter María Piedad; to my brothers Pedro, Ferney, Carlos and Linda Piedad. Bio D S. A, Colombia, who generously donated the PREMIUM GOLD BIODIESEL to carry out all the laboratory tests and start up the functional model, and the test vehicle. Eng. Erika Díaz; Eng. Danisa Leguizamón. http://www.biodsa.com.co/?lang=es Technological School Central Technical Institute, Bogotá D.C. Colombia. Eng. Jim Landinez Cañón; M.Sc. Alejandro Martínez. https://etitc.edu.co/en/; Colombian Federation of Biofuels. Eng. Alfonso Santos; Eng. Carlos Graterón; Eng. Jorge Bendeck. https://www.fedebiocombustibles.com/ Special thanks to: Professor PhD Luis Eduardo Benítez Hernández; National University of Colombia. Professor PhD Carlos Alberto Guerrero Fajardo; National University of Colombia. Professor PhD John Ramiro Agudelo Santamaría; University of Antioquia, Colombia. M. Sc Yordanka Reyes Cruz; Petroleum Research Center, City of Havana, Cuba; Federal University of Rio de Janeiro, Brazil.

Additional information

There is an authoritative summary, published in the proceedings of the EUBCE 2021 event (ETA Florence Renewable Energies. www.etaflorence.it); From that summary I have taken some elements of my authorship (the same author of this chapter) that are part of the preliminary investigation of this chapter, in which some additional findings are presented. From what was published in the EUBCE minutes, the use of elements was authorized. The cited abstract was not peer reviewed.

Ahmad Shahi

Chapters authored

Related collaborators

Abdelrahman Elfaki

Christine Chan

Claire Laudy

Rodziah Atan

Md. Nasir Sulaiman

Saravanan Muthaiyah

Chin-Kuan Ho

Somnuk Phon-Amnuaisuk

Simon Suigen Guo

Robert Harrison