DESCRIPTION

LIQUID FUEL CONDITIONING METHOD AND DEVICE

Technical field

This invention relates to a method for conditioning liquid fuel.

The invention also relates to a device for conditioning liquid fuel.

In particular, the invention relates to a method and a device for conditioning liquid fuel for internal combustion engines and combustion systems.

Background art

Internal combustion engines powered, for example, with diesel fuel, also referred to simply as diesel engines, are currently installed on numerous vehicles, designed both for private and commercial use, due to their excellent features such as low specific fuel consumption, high thermal efficiency, high compression ratio and high reliability.

Unfortunately, amongst the drawbacks related to the use of diesel engines there is the fact that they emit a large quantity of pollutants, and this tends to negatively affect the quality of the air, in particular in large city where the traffic is very heavy.

The term “pollutants” refers basically to emissions of particulate and nitrogen oxides (NOx).

These circumstances have pushed automobile manufacturers to modify the design of the engine in order to optimise the performance levels and scientists have carried out research to identify alternative methods to reduce the emissions (for example, new fuels or new fuel additives).

The main techniques used to reduce engine emissions comprise providing the engines with additional components, such as, for example, the diesel particulate filter (DPF) which is installed downstream of the engine to intercept the particulate present in the exhaust gases.

In addition to solutions relating to additional engine components there are also chemical solutions; by modifying the combustion characteristics of the fuel it is in fact possible to obtain better engine performance levels and therefore a greater saving of fuel with a reduction in the harmful emissions of the exhaust gases.

The addition of metal particles in the fuels has been shown to be an effective method for reducing these harmful emissions, as well as improving the efficiency of the engine.

The metal additives consist mainly of compounds designed to disperse completely in the diesel or in the petrol.

Researchers have studied various metals such as manganese (Mn), iron (Fe), copper (Cu), aluminium (Al), beryllium (Be), cerium (Ce), and platinum (Pt) in order to understand which metals are most suitable for the purpose.

Modifying the fuel could replace traditional methods which are used to reduce emissions with a twofold advantage; on the one hand it would not require the installation of devices downstream of the engine and, on the other hand, it would improve the combustion and performance of the engine.

Prior art solutions add metal additives to the fuel in order to intensify the oxidisation process of the fuel in diesel engines, to allow a more complete combustion, to reduce harmful emissions and to act as a stabilising, antioxidant and surface-active agent.

The operating principle proposed is that the metals act as catalysts for the combustion process; in reality, two mechanisms have been proposed for explaining the advantages resulting from the use of metal additives to reduce the emissions of soot.

It has been suggested that during the combustion process the metal additive reacts with the water, producing hydroxyl radicals which favour oxidisation of the particulate; alternatively, the additives react directly with the carbon atoms in the particulate, thereby lowering the oxidisation temperature. Very briefly, there are numerous advantages connected to the use of fuel doped with metal additives.

Experimental studies on metal nanoparticles added to the diesel, in an internal combustion engine, have demonstrated that the inclusion of nanoparticles in the fuel acts as an oxidising catalyst, accelerates the propagation of the flame inside the cylinder, lowers the activation temperature of the carbon and, subsequently, promotes a complete combustion, reducing the specific fuel consumption.

Researchers have used metal additives with nanometric dimensions and the reason is the better surface/volume ratio, which provides more contact surface for a rapid combustion. The inclusion of the nano-metallic particle in the fuel therefore has several advantages with respect to the micro- metallic particle.

Researchers agree on the fact that the use of nanoparticles in the formulation of the fuel can provide a significant improvement in the field of application of the system and suggest that the best technique for producing nanomaterials is mechanical grinding and thermal plasma treatment together with the sol-gel technology.

There are basically two prior art methods currently used for adding metal additive to fuels, both through the method for mixing powder and sol-gel; however, the method for mixing powder is less used on account of its high cost.

The sol-gel method is also not free of drawbacks since, for example, it requires more than thirty hours for performance of the entire process.

Another aspect which is not without problems is that connected to the mixing of the nanoparticles in the fuel. In effect, if the nanoparticles not suitably mixed they tend to form lumps and this may cause a worsening of the combustion properties but also an increase in the probability of clogging of the fuel injection system. The known methods relating to the addition of metal nanoparticles to liquid fuel therefore have several problems, both in terms of costs and in terms of time.

Disclosure of the invention

The aim of the invention is to overcome the drawbacks of the prior art by providing a method of conditioning fuel which is effective and practical to implement.

A further aim of the invention is to provide a method for conditioning fuel which is inexpensive to implement.

Another aim of the invention is to provide a device for conditioning fuel which allows the drawbacks of the prior art to be overcome.

Another aim of the invention is to provide a device for conditioning fuel which is effective and practical to operate.

Brief description of the drawings

The technical features of the invention, with reference to the above- mentioned aims, are clearly described in the appended claims and the advantages are apparent from the detailed description which follows, with reference to the accompanying drawings in which:

Figure 1 illustrates a schematic cross section of a preferred embodiment of the device for conditioning fuel according to the invention;

- Figures 2 and 3 illustrate, respectively, cross section schematic views of two variant embodiments of the device of Figure 1.

Detailed description of preferred embodiments of the invention

The invention proposes a method for conditioning liquid fuel for supplying internal combustion engines, comprising the step of dispersing metal additives in the liquid fuel in the form of nanoparticles and/or sub nanometric particles. At the same time, with reference to the accompanying drawings, the invention relates to a device 1 for conditioning fuel.

For the purposes of the description, metal nanoparticles will be referred to, this also meaning sub-nanometric particles.

Similarly, reference is made without distinction in this description to either fuel or liquid fuel.

The step of dispersing metal additives in the liquid fuel is actuated by means of a leaching process.

Leaching is a process used for extracting and separating metal substances such as, for example, copper and iron and normally consists in the depositing and migration of particles from the pure mineral to an acid chemical solution.

For the purpose of the invention, a metal conduit 2 has been considered in place of the pure mineral and the fuel may be seen as the solution in which the metal nanoparticles migrate from the surface of the same solid metal.

A conditioning device 1 comprising a section of metal conduit 2 designed to be passed through by the fuel, not illustrated, designed to be designed to be p[assed through by the fluid, not illustrated, has been installed, upstream of an internal combustion engine with a diesel cycle, along the fuel supply line.

The section of metal conduit 2, hereinafter also referred to only as metal conduit 2, has a cylindrical shape and has a central axis A of longitudinal extension.

The above-mentioned section of metal conduit 2 is advantageously made of a metal alloy comprising copper (Cu) and/or iron (Fe).

Advantageously, further and/or other metals are also comprised in the metal alloy with which the above-mentioned section of conduit is made.

By way of example, the metal alloy comprises one or more of the following metals: manganese, barium, platinum, aluminium, samarium, magnesium, cerium and silver. According to alternative embodiments of the invention, not illustrated, instead of an entirely metal conduit 2 the conduit is made of a non-metallic material but with a coating made of metallic material at least of the surface facing the fuel, so as to allow the migration of the metal particles towards the fuel.

The device 1 for conditioning fuel according to the invention is located on the line, not illustrated, for supplying liquid fuel to an internal combustion engine of a vehicle, which is also not illustrated.

The device 1 comprises a hollow cylindrical body 3 closed at its ends by two flanges or heads 4, 5.

The inside of the hollow cylindrical body 3, centrally with respect to it, houses the above-mentioned section of metal conduit 2 in fluid communication with the above-mentioned and not illustrated line for supplying the liquid fuel to the engine.

The section of metal conduit 2 is provided on the inside with a sort of labyrinth-like path for the liquid fuel which is repeatedly diverted relative to the longitudinal axis of the conduit 2.

Advantageously, the above-mentioned labyrinth-like path is made by inserting a spiral element 6 inside the metal conduit 2.

Advantageously, according to a preferred embodiment, the spiral element 6 is made of copper.

As illustrated in Figure 1 , the device 1 comprises a resistor 7 located in contact with the metal conduit 2 for heating the latter.

The resistor 7 of Figure 1 extends longitudinally parallel to the above- mentioned axis A substantially for the entire length of the cylindrical body 3.

With reference to the variant embodiment illustrated in Figure 2, the device 1 comprises a resistor 7 of reduced longitudinal extension and positioned centrally with respect to the extension of the metal conduit 2.

Again with reference to the embodiment of Figure 2, the conditioning device 1 comprises two electric coils 8 wound around the metal conduit 2 and designed to generate an electromagnetic field acting on the metal conduit 2 and on the liquid fuel flowing in it.

The two electric coils 8 are positioned at lateral portions of the metal conduit 2, on opposite sides of the resistor 7.

Advantageously, the resistor 7, in both the embodiments illustrated, is configured for heating the metal conduit 2 and keeping it at a temperature of between 20°C and 50°C during the circulation of the fuel inside it.

With reference to the further variant embodiment illustrated in Figure 3, the device 1 comprises, positioned adjacent to each other longitudinally, an electric coil 8 and a heat exchanger 9.

The electric coil 8 is wrapped around the metal conduit 2 and designed to generate an electromagnetic field acting on the metal conduit 2.

Advantageously, the heat exchanger 9 is configured for heating the metal conduit 2 and keeping it at a temperature of between 20°C and 50°C during the circulation of the fuel inside it.

The heat exchanger 9 comprise an annular compartment 10 extending circumferentially around the metal conduit 2 and designed to circulate inside it a heat exchange carrier fluid.

For the circulation of the carrier fluid the heat exchanger 9 comprises two channels 11 , 12 respectively for the inlet and outlet of the fluid into and from the annular compartment 10, made on the head 4.

Advantageously, the carrier fluid is the cooling lubricating circulating in the internal combustion engine.

Alternatively, the carrier fluid is the cooling liquid of the internal combustion engine.

The above-mentioned resistor 7 and heat exchanger 9 define, for the conditioning device 1 , heating means operating on the metal conduit 2 to heat it and keep it at a temperature of between 20°C and 50°C.

With reference to the above-mentioned heating means, it has been noted experimentally that the reaching and the maintaining of a predetermined thermal state in the metal conduit 2 has significant importance in setting up a leaching process such as to cause the detachment of metal particles from the metal conduit 2 and the relative metal dispersion of them in the liquid fuel flowing inside the conduit 2.

With reference to the electric coils, it has been noted experimentally that the exposure of the liquid fuel (flowing inside a metal conduit 2) to an electromagnetic field contributes towards increasing the dispersion in the fuel of metal additives in the form of nanoparticles detached from the metal conduit 2.

In use, with reference to the accompanying drawings, the conditioning device 1 and, more specifically, the metal conduit 2 is crossed by liquid fuel.

The above-mentioned section of conduit 2 is subjected to heating and advantageously its temperature is kept at a value of between 20°C and 50°C.

The reaching of this adequate thermal state in the conduit 2 advantageously allows, as noted experimentally, the activation of a leaching process after which metallic particles (nanoparticles or sub nanometric aggregates) detach from the metal conduit and mix in the fuel flowing inside the metal conduit.

The metal detaches, following the action of the heating, in the form of sub nanometric aggregates and/or nanoparticles.

As mentioned, experimental tests have shown that a step of subjecting the metal conduit 2 to an electromagnetic field favours the above-mentioned leaching process.

Advantageously, therefore, the above-mentioned section of metal conduit 2 is subjected to an electromagnetic field when crossed by the fuel.

Advantageously, the above-mentioned step of subjecting the metal conduit to an electromagnetic field is actuated by preparing one or more electric coils 8 and winding them about the above-mentioned metal conduit 2.

The electromagnetic field acting on the section of metal conduit 2, together with the reaching of an adequate thermal state of the metal conduit 2, advantageously allows the setting up of the above-mentioned leaching process.

In particular, thanks to the thermal state and the electromagnetic field (if present) and the relative surface polarisation of the metal conduit which is created, the atoms of the metal (copper, iron, etc.) are made susceptible to detachment from the surface in the form of sub-nanometric aggregates, which are then dispersed in the fuel flowing inside the conduit, in contact with the surface.

Basically, metal nanoparticles or sub-nanometric aggregates migrate from the surface of the solid metal forming the section of metal conduit 2 to the fuel circulating inside it.

By using suitable instrumentation, for example based on the technique best known as inductively coupled plasma mass spectrometry (ICP-MS), it has been possible to assess the concentration of metals in the liquid fuel. The concentration of metal particles has been shown to be effective both in terms of removal of the pollutant products of the combustion and in terms of optimising the combustion.

It has been be seen experimentally that variations in the temperature of the metal conduit imply consequent variations in the degree of dispersion of the metal particles in the fuel.

Following the heating or cooling of the metal conduit the concentration of certain metals in the form of nanoparticles varies in the fuel flowing inside the conduit.

In particular, as has been be noted, the release of particles of copper from the metal conduit (made of alloy containing copper) to the fuel increases with the increase in temperature, within predetermined temperature ranges.

It is also been found experimentally that variations in the intensity of the electromagnetic field implies different degrees of dispersion of metal particles in the fuel. Advantageously the spiral element 6 located inside the metal conduit 2 is also made of the same metal material, so as to amplify the detachment action of the particles and, therefore, the effectiveness of the conditioning the fuel.

Experimental tests, carried out on a conditioning device 1 of the type shown in Figure 2, that is to say, comprising both a resistor 7 and a coil 8, have demonstrated (with a flow rate of diesel fuel of 30 kg/h, an electricity supply to the coil and the resistor of 13 Volts and a temperature of the metal conduit of between 30°C and 40°C) an enrichment in the content of copper in the fuel changing from 0.01 mg/kg (in the initial fuel) to values of between 0.12 and 0.19 mg/kg (in the same fuel after it has circulated in the conditioning device).

The invention achieves the preset aims and brings important advantages.

A undoubted advantage connected to the method and to the device for conditioning fuel according to the invention is due to the fact that, basically, the leaching achieves simultaneously both the ‘production’ of metal nanoparticles and their‘addition’ to the fuel. This therefore allows in a single step, and with a single device, what is normally achieved, according to the prior art, in several different steps: that is to say, the extraction of metal nanoparticles, their stabilising and the subsequent mixing in the liquid fuel.

By using the method according to the invention is not therefore necessary to carry out any activities for preparing the fuel with additives and the preparation times are also reduced to a minimum.

The circumstances just indicated directly result also in an evident reduction of the production costs of the fuel admixed with metal particles.