System and method for biofuel use

Abstract

System (1) for biofuel use and presenting: at least one vehicle (2) provided with an internal combustion engine (3) and an operational tank (4) configured to contain fuel intended for supplying the internal combustion engine (3); and a fuel system (12) configured to supply into the operational tank (4) of the vehicle (2) biofuel or, alternatively, fossil fuel so as to fill the operational tank (4) of the vehicle (2). The fuel system (12) is configured also to extract from the operational tank (4) of the vehicle (2) biofuel or, alternatively, fossil fuel so as to empty the operational tank (4) of the vehicle (2).

Description

[0001] SYSTEM AND METHOD FOR BIOFUEL USE

[0002] Cross-Reference to Related Patent Applications

[0003] This application claims the priority of Italian Patent Application No. 102024000026028 filed on November 19, 2024, the content of which is hereby incorporated by reference.

[0004] Technical Field

[0005] The present invention relates to a system and a method for biofuel use.

[0006] The present invention finds advantageous application to biodiesel use, to which the discussion will make explicit reference without thereby losing generality.

[0007] Prior Art

[0008] The adoption of biodiesel allows for obtaining numerous environmental benefits but also presents some technical limitations especially in the presence of a cold climate.

[0009] For example, biodiesel is a biofuel that has a cloud point between -5 and +15°C, significantly higher than traditional fossil-based diesel and therefore biodiesel can solidify or become too viscous to be effectively pumped through the engine fuel supply system. If biodiesel solidifies in the tank, in the fuel lines, in the fuel pump or in the injectors, the internal combustion engine may have difficulty starting or may not start at all.

[0010] The technology described in patent application WO2022118352A1 allows for overcoming the problems in the use of mixtures composed of fossil diesel and biodiesel (in which it is possible to reach up to 100% biodiesel) by installing on the vehicle a biodiesel fuel system configured to heat (when necessary) the biodiesel before its use and to clean the fuel supply lines from biodiesel when the internal combustion engine is stopped (for a prolonged stop).

[0011] However, in some cases the application of the device described in patent application WO2022118352A1 may not be technically convenient in vehicles or machinery equipped with a diesel engine in which the bulk of the system components represents installation complexity and / or limits the functionality of the vehicle or machinery. Furthermore, the modification of the individual vehicle can be inconvenient when there are multiple vehicles or utilizer machinery in the same place. For example, an agricultural company that uses different work vehicles.

[0012] Another example could be a company that manages a large warehouse and uses different vehicles for internal merchandise handling or a construction site where the operation of different vehicles alternates depending on the operations to be performed.

[0013] Patent application EP2634400A1 describes a power plant comprising an internal combustion engine suitable for operating with alternative fuels, such as pyrolysis oil-based fuels; a fuel tank park can comprise tanks for alternative fuels and a switching fuel or its components and, in some embodiments, tanks for crude petroleum-based fuels.

[0014] Description of the Invention

[0015] The purpose of the present invention is to provide a system and a method for biofuel use in multiple vehicles or utilizer machinery that allows for increasing the quantity of biofuel that is used under the same conditions and at the same time is of easy and economical implementation.

[0016] According to the present invention, a system and a method for biofuel use are provided, according to what is claimed by the attached claims. The claims describe preferred embodiments of the present invention forming an integral part of the present description.

[0017] Brief Description of the Drawings

[0018] The present invention will now be described with reference to the attached drawings, which illustrate some non-limiting examples of implementation thereof, in which:

[0019] • Figure 1 is a schematic view of a biodiesel use system;

[0020] • Figures 2-5 show the biodiesel use system of Figure 1 with emphasis on the paths followed by fluids during different operating modes; and

[0021] • Figure 6 is a schematic view of a variant of the biodiesel use system of Figure 1 .

[0022] Preferred Embodiments of the Invention

[0023] In Figure 1 , with reference number 1 a biofuel use system is indicated as a whole, in particular biodiesel. The use system 1 comprises a plurality (a fleet) of mobile vehicles 2 (typically work vehicles, only one of which is schematically illustrated in Figure 1), each of which is provided with an internal combustion engine 3 with spontaneous ignition of the mixture (that is operating according to the Diesel cycle) configured to provide the power necessary for traction (for example the internal combustion engine 3 can be directly connected to the drive wheels or can be part of a series hybrid system). According to an alternative embodiment, the use system 1 could comprise in addition to vehicles 2 also machinery each provided with an internal combustion engine 3 with spontaneous ignition of the mixture.

[0024] Each vehicle 2 is mobile in that it is able to move autonomously and freely through the traction thrust generated (directly or indirectly) by the internal combustion engine 3.

[0025] In particular, each vehicle 2 comprises a single operational tank 4 containing fuel (and in particular only one type of fuel at a time), a delivery line 5 that draws fuel from the operational tank 4 to supply fuel to the injectors of the internal combustion engine 3, a high-pressure fuel pump 6 that is arranged along the delivery line 5, and a return line 7 that receives from the internal combustion engine 3 the excess fuel and ends in the tank 4. Along the delivery line 5 there are also arranged a check valve 8 that allows fuel flow only towards the internal combustion engine 3 and a filter 9. The operational tank 4 can be the original component of a vehicle 2 or can be a new component that has been installed in the vehicle 2 for the use of biodiesel and, for example, could be provided with a heating system. In other words, the operational tank 4 of the vehicle 2 containing fuel could be coupled with a heating system to maintain the fuel at a predetermined minimum temperature.

[0026] It is important to note that each vehicle 2 comprises a single operational tank 4 of fuel and therefore can contain only one type of fuel at a time. That is, each vehicle 2, having a single operational tank 4 of fuel, cannot contain simultaneously both biodiesel and fossil-based diesel, but can contain only biodiesel, only fossil-based diesel or only a mixture of biodiesel and fossil-based diesel.

[0027] Furthermore, each vehicle 2 comprises a supply port 10 that is connected to the delivery line 5 (or, alternatively, could be connected directly to the tank 4) and can be used to supply (without passing through the internal combustion engine 3) fuel to the operational tank 4 and an extraction port 11 that is connected to the delivery line 5 (or, alternatively, could be connected directly to the tank 4) and can be used to draw (without passing through the internal combustion engine 3) fuel from the tank 4.

[0028] The use system 1 comprises a fuel system 12 that is separate and independent from the vehicles 2 and is arranged in a fixed position (that is, it is not arranged on board a vehicle but is installed on the ground) in a refueling area accessible by the vehicles 2. In use, the fuel system 12 can be temporarily connected to a vehicle 2 that autonomously reaches the refueling area for fuel refueling.

[0029] The fuel system 12 comprises a main tank 13 intended to contain biodiesel and an auxiliary tank 14 intended to contain fossil-based diesel. The main tank 13 is provided with a heating device that is configured to heat, when necessary, the biodiesel contained in the main tank 13 so as to maintain the biodiesel contained in the main tank 13 at a temperature adequately higher than the solidification temperature of biodiesel; the heating device can generate heat using electrical energy or by burning a (small) part of the biodiesel contained in the main tank 13 or a part of the fossil-based diesel contained in the auxiliary tank 14.

[0030] According to a possible embodiment, the tank 13 is provided with an external circulation (movement) circuit that is equipped with a pump and is configured to draw part of the biodiesel from the tank 13 and then re-immerse the biodiesel in the tank 13 possibly integrating filters for cleaning the biodiesel put into circulation. The function of the external circulation (movement) circuit is to keep the biodiesel in motion as the simple movement itself reduces biological activity and uniformizes the temperature inside the main tank 13.

[0031] According to an alternative embodiment, a concentration sensor is arranged in the main tank 13 that also provides a reliable measurement of the viscosity and temperature of the fuel. In this way, the process of heating the biodiesel contained in the main tank 13 is not controlled according to the temperature of the biodiesel in the main tank 13 but is controlled according to the viscosity of the biodiesel in the main tank 13; consequently, the control of the heating process becomes more precise as the ultimate purpose of heating biodiesel is not to increase the temperature of biodiesel but to keep the biodiesel sufficiently fluid.

[0032] In other words, the ultimate purpose of heating the biodiesel is the lowering of its viscosity: the curve of variation of the viscosity of biodiesel as the temperature varies is known in the literature for all types of biodiesel, however it is not known for all possible mixtures of fossil-based diesel and biodiesel that can form over time in the main tank 13. Normally, biodiesel found in the main tank 13 is considered ready when it reaches a certain temperature, at which a certain viscosity is believed to correspond; however, having the concentration sensor available in the main tank 13 it is possible to directly measure the viscosity of the biodiesel stopping the heating process exactly at the desired viscosity thus avoiding excessively heating the biodiesel (with the risk of biodiesel degradation and excessive energy consumption) or heating too little the biodiesel (putting stress on the pumps and other components equipped with moving parts).

[0033] The fuel system 12 comprises a supply port 15 that can be temporarily connected to the supply port 10 of the vehicle 2 by means of a flexible tube 16 and comprises an extraction port 17 that can be temporarily connected to the extraction port 1 1 of the vehicle 2 by means of a flexible tube 18.

[0034] The fuel system 12 comprises a three-way supply valve 19 preferably electrically controlled and having two independent inputs and a single outlet, a three-way extraction valve 20 preferably electrically controlled and having a single input and two independent outlets, and a four-way safety valve 21 preferably electrically controlled and having two inputs and two outlets: an outlet of the four-way safety valve 21 is connected to the supply port 15 and an input of the four-way safety valve 21 is connected to the extraction port 17.

[0035] The fuel system 12 comprises a delivery line 22 that originates from the main tank 13 (that is draws from inside the main tank 13) and ends in a first input of the three-way supply valve 19 and a delivery line 23 that originates from the auxiliary tank 14 (that is draws from inside the auxiliary tank 14) and ends in a second input of the three-way supply valve 19. Along the delivery line 22 a check valve 24 is arranged that allows biodiesel flow only from the main tank 13 towards the three-way supply valve 19 (and therefore not vice versa) and a filter 25. Similarly, along the delivery line 23 a check valve 26 is arranged that allows biodiesel flow only from the auxiliary tank 14 towards the three-way supply valve 19 (and therefore not vice versa) and a filter 27.

[0036] The fuel system 12 comprises a return line 28 that originates from a first outlet of the three-way extraction valve 20 and ends in the main tank 13 and a return line 29 that originates from a second outlet of the three-way extraction valve 20 and ends in the auxiliary tank 14.

[0037] The fuel system 12 comprises a delivery line 30 that originates from the outlet of the three-way supply valve 19 and ends in an input of the four-way safety valve 21 and a return line 31 that originates from an outlet of the four-way safety valve 21 and ends in the input of the three-way extraction valve 20.

[0038] The fuel system 12 comprises an interconnection line 32 that connects the delivery line 30 (that is the outlet of the three-way supply valve 19) to the return line 31 (that is to the input of the three-way extraction valve 20) and a circulation pump 33 that is arranged along the interconnection line 32.

[0039] Finally, a control unit 34 is provided that oversees the operation of the fuel system 12.

[0040] The operation of the fuel use system 1 is described below.

[0041] In use, three different operations are performed as described below.

[0042] At the beginning of the use of the vehicle 2, the vehicle 2 is temporarily coupled to the fuel system 12 by connecting the ports 10 and 11 of the vehicle 2 to the ports 15 and 17 of the fuel system 12 through the tubes 16 and 18; initially the operational tank 4 of the vehicle 2 is emptied of fossil-based diesel by transferring its contents to the auxiliary tank 14 of the fuel system 12 (as illustrated in Figure 5 and described in detail below) and subsequently the operational tank 4 of the vehicle 2 is filled with the biodiesel contained in the main tank 13 (as illustrated in Figure 2 and described in detail below).

[0043] During the use of the vehicle 2 and when it is necessary to refuel the vehicle 2 with additional biodiesel, the vehicle 2 autonomously reaches the refueling area where the vehicle 2 is temporarily coupled to the fuel system 12 by connecting only the supply port 10 of the vehicle 2 to the supply port 15 of the fuel system 12 through the tube 16; at this point, the operational tank 4 of the vehicle 2 is (again) filled with the biodiesel contained in the main tank 13 (as illustrated in Figure 2 and described in detail below).

[0044] At the end of the use of the vehicle 2, the vehicle 2 autonomously reaches the refueling area where it is coupled to the fuel system 12 by temporarily connecting the ports 10 and 11 of the vehicle to the ports 15 and 17 of the fuel system 12 through the tubes 16 and 18; initially the operational tank 4 of the vehicle 2 is emptied of biodiesel by transferring its contents to the main tank 13 of the fuel system 12 (as illustrated in Figure 4 and described in detail below) and subsequently the operational tank 4 of the vehicle 2 is filled with the fossil-based diesel contained in the auxiliary tank 14 (as illustrated in Figure 3 and described in detail below). After the operational tank 4 of the vehicle 2 has been (again) filled with fossil-based diesel, the vehicle 2 is left running for a time (for example on the order of 1 -3 minutes) sufficient to consume (burn) all the biodiesel present in the delivery line 5 and inside the internal combustion engine 3 (this time could be used to move the vehicle 2 from the fuel system 12 to the parking area to which a little bit of operation at idle with the vehicle 2 stationary could be added). In other words, at the end of the use of the vehicle 2 and after having filled the operational tank 4 of the vehicle 2 with fossil-based diesel, the internal combustion engine 3 is made to run for a time at least sufficient to consume all the biodiesel remaining in elements that connect the operational tank In this way, at the end of the use of the vehicle 2, substantially only fossil-based diesel is present inside the vehicle 2 and therefore the vehicle 2 can remain stationary (off) even for a long period of time at an ambient temperature lower than the solidification temperature of biodiesel.

[0045] In the use system 1 , it is therefore possible to extract the fossil-based diesel present in the vehicle 2 and replace it with biodiesel already adequately treated (heated) to present the optimal viscosity; it is also possible to perform the reverse operation, that is to extract the biodiesel from the vehicle 2 and replace it with fossil-based diesel, that is with the original fuel. In this way it is possible to refuel the vehicle 2 with already hot biodiesel and it is also possible to replace the unused biodiesel before stopping the vehicle 2, in such a way as to perform the operation of cleaning the hydraulic fuel supply lines inside the vehicle 2.

[0046] According to what is illustrated in Figure 2, to supply biodiesel from the main tank 13 of the fuel system 12 to the operational tank 4 of the vehicle 2, the control unit 34 controls the three-way supply valve 19 to connect the delivery line 22 to the interconnection line 32, controls the three-way extraction valve 20 to isolate the interconnection line 32 from the return lines 28 and 29, and controls the four-way safety valve 21 to connect the delivery line 30 to the supply port 15 (which in turn is connected to the supply port 10 of the vehicle 2). At this point, the control unit 34 can start the circulation pump 33 to pump the biodiesel from the main tank 13 of the fuel system 12 to the operational tank 4 of the vehicle 2.

[0047] According to what is illustrated in Figure 3, to supply fossil-based diesel from the auxiliary tank 14 of the fuel system 12 to the operational tank 4 of the vehicle 2, the control unit 34 controls the three-way supply valve 19 to connect the delivery line 23 to the interconnection line 32, controls the three-way extraction valve

[0048] 20 to isolate the interconnection line 32 from the return lines 28 and 29, and controls the four-way safety valve

[0049] 21 to connect the delivery line 30 to the supply port 15 (which in turn is connected to the supply port 10 of the vehicle 2). At this point, the control unit 34 can start the circulation pump 33 to pump the fossil-based diesel from the auxiliary tank 14 of the fuel system 12 to the operational tank 4 of the vehicle 2.

[0050] According to what is illustrated in Figure 4, to supply biodiesel from the operational tank 4 of the vehicle 2 to the main tank 13 of the fuel system 12, the control unit 34 controls the three-way supply valve 19 to isolate the interconnection line 32 from the delivery lines 22 and 23, controls the three-way extraction valve 20 to connect the interconnection line 32 to the return line 28, and controls the four-way safety valve 21 to connect the return line 31 to the extraction port 17 (which in turn is connected to the extraction port 11 of the vehicle 2). At this point, the control unit 34 can start the circulation pump 33 to pump the biodiesel from the operational tank 4 of the vehicle 2 to the main tank 13 of the fuel system 12.

[0051] According to what is illustrated in Figure 5, to supply fossil-based diesel from the operational tank 4 of the vehicle 2 to the auxiliary tank 14 of the fuel system 12, the control unit 34 controls the three-way supply valve 19 to isolate the interconnection line 32 from the delivery lines 22 and 23, controls the three-way extraction valve 20 to connect the interconnection line 32 to the return line 29, and controls the four-way safety valve 21 to connect the return line 31 to the extraction port 17 (which in turn is connected to the extraction port 1 1 of the vehicle 2). At this point, the control unit 34 can start the circulation pump 33 to pump the fossil-based diesel from the operational tank 4 of the vehicle 2 to the auxiliary tank 14 of the fuel system 12.

[0052] Generally, it is not necessary to heat the biodiesel inside the operational tank 4 of the vehicle 2 as the vehicle 2 is a work vehicle that is used continuously after receiving the biodiesel consuming the biodiesel in a relatively short time (at most a few hours) and as the operational tank 4 of the vehicle 2 normally has a good thermal insulation that helps to keep the temperature of the biodiesel inside the tank 4 for a long time. Furthermore, in case of particularly cold outside temperatures, the biodiesel can be supplied to the operational tank 4 of the vehicle 2 at a temperature adequately higher (for example 40-60°C) to its solidification temperature (normally 10-15°C) to remain sufficiently hot even after a few hours from the supply to the operational tank 4 of the vehicle 2.

[0053] According to a possible embodiment, the operational tank 4 of the vehicle 2 can be covered with an external coating of thermally insulating material to slow down the cooling of the biodiesel contained in the operational tank 4 of the vehicle 2.

[0054] According to a possible embodiment, the operational tank 4 of the vehicle 2 can be provided with a heating device that slows down the cooling of the biodiesel contained in the operational tank 4 of the vehicle 2 and uses electrical energy produced by the electrical generator coupled to the internal combustion engine 3, uses hot engine oil from the internal combustion engine 3, uses hot exhaust gases emitted by the internal combustion engine 3, or uses the cooling liquid of the internal combustion engine 3. The heating device must generate contained thermal powers as its objective is not to heat the biodiesel contained in the operational tank 4 of the vehicle 2 but only to slow down the cooling of the biodiesel contained in the operational tank 4 of the vehicle 2.

[0055] When fuel is extracted from the operational tank 4 of the vehicle 2, it is not possible to effect a complete removal of the volume of fluid contained in the operational tank 4; this is due to the fact that the extraction line that originates inside the operational tank 4 is always placed one or two centimeters from the bottom of the operational tank 4. Consequently when the vehicle 2 is refueled a mixture of two fuels will be obtained, that is a mixture of biodiesel and fossil-based diesel.

[0056] According to a possible embodiment, along the return line 7 a concentration sensor is installed that is configured to determine the composition of the fuel that flows along the return line 7 and in particular is configured to determine the percentage (concentration) of biodiesel and, consequently, the percentage (concentration) of fossil-based diesel. In this embodiment, a cleaning (washing) cycle can be controlled according to the composition of the fuel flowing along the return line 7; that is, the cleaning (washing) cycle is stopped when the percentage (fraction) of biodiesel in the fuel flowing along the return line 7 drops below a predetermined threshold value. Thanks to the use of the concentration sensor, the cleaning (washing) cycle is much more effective (that is it is guaranteed to always reach the desired result in terms of biodiesel residue) and much more efficient (that is the duration of the cleaning cycle is always the minimum necessary to reach the desired result in terms of biodiesel residue regardless of the random variation of the surrounding conditions).

[0057] If one wants to avoid "contaminating" the biodiesel contained in the main tank 13 with fossil-based diesel when extracting the contents from the operational tank 4 of the vehicle 2 (as illustrated in Figure 4) and similarly if one wants to avoid "contaminating" the fossil-based diesel contained in the auxiliary tank 14 with biodiesel when extracting the contents from the operational tank 4 of the vehicle 2 (as illustrated in Figure 5), it is possible, as illustrated in Figure 6, to provide in the fuel system 12 an additional storage tank 35 in which to direct the fuel that is extracted from the operational tank 4 of the vehicle 2. The fuel that is collected in the storage tank 35 can be used to refuel a vehicle 2 at a later time simply by mixing it with other biodiesel present in the main tank 13 (to increase the presence of biodiesel in the mixture) or with other fossil-based diesel present in the auxiliary tank 14 (to increase the presence of fossil-based diesel in the mixture). In other words, the fuel that is collected in the storage tank 35 can be used for the creation of desired mixtures composed of fossil-based diesel and biodiesel. Possibly, the fuel that is collected each time in the storage tank 35 could be used to supply the heating device of the main tank 13.

[0058] Pure biodiesel ensures the best environmental performance but the worst degradability and cold viscosity performance. For this reason, commonly mixtures composed of fossil-based diesel and biodiesel are used that can be low in biodiesel content (for example 20-30% biodiesel) or high in biodiesel content (for example 70-80% biodiesel). The fuel that is collected in the storage tank 35 is very well suited for the creation of desired mixtures composed of fossil-based diesel and biodiesel; for this purpose, the storage tank 35 can be provided with a concentration (characterization) sensor that is configured to determine the composition of the fuel that is inside the storage tank 35 and in particular is configured to determine the percentage (concentration) of biodiesel, and, consequently, the percentage (concentration) of fossil-based diesel. Knowing the composition of the fuel that is inside the storage tank 35, it becomes simple to use the fuel that is inside the storage tank 35 for the creation of desired mixtures composed of fossil-based diesel and biodiesel.

[0059] If the vehicle 2 is equipped with a particulate filter and has been refueled with biodiesel from the main tank 13 or with a mixture of fossil-based diesel and biodiesel with high biodiesel content, there are generally difficulties in the regeneration operation of the particulate filter itself.

[0060] In patent application WO2022118352A1 a method is described for the regeneration of the particulate filter using biodiesel or mixtures of fossil-based diesel and biodiesel with a biodiesel concentration greater than 7%; this regeneration method provides for the addition of components that make the system more complex. To overcome this increase in complexity, it is possible to connect the vehicle 2 to the fuel system 12 when the regeneration of the particulate filter must be performed and in this way the regeneration of the particulate filter is performed using only fossil-based diesel drawn from the tank 14 and sent to the vehicle 2 (that is directly to the internal combustion engine 3) through the supply port 10. In other words, the vehicle 2 is connected to the fuel system 12 immediately before beginning the regeneration of the particulate filter and therefore the fossil diesel used for the regeneration of the particulate filter is supplied directly to the internal combustion engine 3 of the vehicle 2 through the supply port 10.

[0061] In particular, for the regeneration it is possible to use the fossil-based diesel drawn from the tank 14 or it is possible to use the mixture of fossil-based diesel and biodiesel drawn from the tank 35 (of course when the tank 35 is present) if it has a sufficiently low percentage of biodiesel.

[0062] In practice, when the vehicle 2 is connected to the fuel system 12 to perform the regeneration of the particulate filter, only the connection of the supply port 10 of the vehicle 1 to the supply port 15 of the fuel system 12 is sufficient and the emptying of the operational tank 4 of the vehicle 2 of biodiesel will not be performed as it is not necessary. In this way, it is possible to speed up the regeneration operation of the particulate filter and allow the vehicle 2 to resume its operations in shorter times.

[0063] According to a further embodiment not illustrated, on board the vehicle 2 there is a regeneration tank containing only fossil-based diesel that is used only during the regeneration of the particulate filter. The regeneration tank is sized to allow at least one regeneration of the particulate filter in cases where the connection of the vehicle 2 to the fuel system 12 is not convenient, for example when the vehicle 2 is engaged in an operation that cannot be interrupted. The regeneration tank is hydraulically connected to the lines 5 and 7 so that its filling is possible through the connection of the ports 10 and 11. In other words, the internal combustion engine 3 of the mobile vehicle 2 comprises an exhaust system provided with at least one particulate filter, the operational tank 4 of the vehicle is the only tank that is used for normal operation of the internal combustion engine 3 in the absence of particulate filter regeneration, and the regeneration tank is used only for the operation of the internal combustion engine 3 during particulate filter regeneration. The regeneration tank is smaller than the operational tank 4 and preferably has a capacity not exceeding 10% of a capacity of the operational tank 4.

[0064] The control unit 34 can be configured to acquire, process, store and possibly transferto other electronic devices information on the operation of the vehicle 2 (for example information present on the CAN bus network of the vehicle 2). In this way it is possible to keep track of all the parameters of the vehicle 2 and the fuel system 12, for the entire operating time, having important information to evaluate efficiency and emissions. The collected data can be related to individual vehicles 2 (or machinery), in this way the company can also evaluate whether the vehicles 2 (or machinery) are exploited differently and prepare strategies for their more efficient use. For example, the control unit 34 knows when a particulate filter regeneration event is about to occur and can for example inhibit it until the next connection of the vehicle 2 to the fuel system 12. Furthermore, the data read can be used to obtain environmental certifications where provided.

[0065] The control unit 34, receiving information from sensors present on the vehicle 2 and on the fuel system 12, is able to communicate to the operator, for example by means of a warning light or sound signal, when it is necessary to connect the vehicle 2 to the fuel system 12. For example, when the vehicle 2 (or machinery) is switched on at the beginning of the work shift using fossil-based diesel, the control unit 34 communicates when the vehicle 2 is ready (for example if it is at temperature) for the transition to biodiesel through connection to the fuel system 12. Or at the end of the work shift, the control unit 34 communicates that it is time to perform the cleaning prior to the end of use of the vehicle 2 (or machinery 2). If the vehicle 2 were switched off without performing the cleaning, the control unit 34 could warn that this operation was omitted, avoiding problems the next day.

[0066] The signals can also be set by the company that owns or uses the vehicles 2 (or machinery), which can therefore program when they must be connected to the fuel system 12.

[0067] The warning light or sound signal can also be used to signal to the operator of the vehicle 2 (or machinery) when it needs fuel refueling during its operation or when connection to the fuel system 12 is necessary to perform the regeneration operation.

[0068] The control unit 34 can be configured to implement vehicle (or machinery) 2 management strategies also during connection with the fuel system 12. For example, during refueling, the control unit 34 could switch off the internal combustion engine 3 for greater safety.

[0069] Preferably, the ports 10-11 , 15 and 17 are provided with quick couplers to quickly perform the (hydraulic) connections.

[0070] The check valves 24 and 26 are not essential for the operation of the fuel system 12 but are useful. According to other embodiments not illustrated, the position of the check valves 24 and 26 could be different or one or more of the check valves 24 and 26 could not be present.

[0071] The filters 25 and 27 are useful but not essential for the operation of the hydraulic circuit. According to other embodiments not illustrated, the position of the filters 25 and 27 could be different or one or more of the filters 25 and 27 could not be present.

[0072] As described previously, the lines where biodiesel flows are emptied each time completely to avoid that biodiesel can, in cold climatic conditions, block inside the circuits and limit their functionality. Alternatively, by inserting appropriate valves, it is possible to clean the lines where biodiesel normally flows with fossil-based diesel (that is by making fossil-based diesel flow that replaces the biodiesel). For those lines that it is not possible to clean from biodiesel, heating devices can be used that by keeping the biodiesel hot prevent its solidification.

[0073] It is important to clarify that in each vehicle 2 the operational fuel tank 4 (which generally, but not necessarily, can be the same tank that was installed in the vehicle 2 at the time of its production) is configured to "breathe", that is to compensate for the variations in volume of the fuel due to filling, emptying and temperature variations. That is, the operational fuel tank 4 of each vehicle 2 is equipped with a known ventilation system composed of one or more devices that regulate the entry and exit of air or vapors. During filling the fuel that enters the operational tank 4 pushes out the air (and fuel vapors): a vent duct allows the exit of air, avoiding overpressures and "bounces" to the pump. When the internal combustion engine 3 consumes fuel or when the operational tank 4 is emptied, the fuel level in the operational tank 4 drops and air enters to prevent vacuum formation; the air intake occurs through a ventilation valve, which opens only in depression.

[0074] The description has made explicit reference to the use of biodiesel, but the use system 1 described above can also be used for the use of a biofuel different from biodiesel.

[0075] The embodiments described here can be combined with each other without departing from the scope of protection of the present invention.

[0076] The use system 1 described above has numerous advantages.

[0077] First, the use system 1 described above allows for considerably increasing the quantity of biodiesel that is used under the same conditions when managing a fleet of vehicles 2 (even if different from each other with the only condition that they can use the same type of fuel) used in the same work place. This result is achieved thanks to the fact that instead of having to install in each vehicle 2 a fuel supply system configured to manage and condition biodiesel autonomously, a single common fuel system 12 is used that takes care of managing and conditioning biodiesel for all vehicles 2 that remain substantially standard. In this way, the biodiesel remains on board the vehicles 2 only during working hours while at the end of the work shift (or in any case before a prolonged stop) the biodiesel is removed from the vehicles 2 and fossil-based diesel is restored.

[0078] Thanks to the use system 1 described above, it is possible to make a fleet of vehicles 2 use biofuel without having to significantly modify the vehicles 2 (if not for the addition of the extraction port 11 which has a modest purchase cost and assembly complexity).

[0079] Furthermore, the use system 1 described above is of relatively simple and economical implementation.

[0080] LIST OF REFERENCE NUMBERS OF THE FIGURES

[0081] 1 use system

[0082] 2 vehicle

[0083] 3 internal combustion engine

[0084] 4 tank 5 delivery line

[0085] 6 high-pressure fuel pump

[0086] 7 return line

[0087] 8 check valve

[0088] 9 filter

[0089] 10 supply port

[0090] 11 extraction port

[0091] 12 fuel system

[0092] 13 main tank

[0093] 14 auxiliary tank

[0094] 15 supply port

[0095] 16 tube

[0096] 17 extraction port

[0097] 18 tube

[0098] 19 three-way supply valve

[0099] 20 three-way extraction valve

[0100] 21 four-way safety valve

[0101] 22 delivery line

[0102] 23 delivery line

[0103] 24 check valve

[0104] 25 filter

[0105] 26 check valve

[0106] 27 filter

[0107] 28 return line

[0108] 29 return line

[0109] 30 delivery line

[0110] 31 return line

[0111] 32 interconnection line

[0112] 33 circulation pump

[0113] 34 control unit

[0114] 35 storage tank

Claims

CLAIMS1 . A use system (1) for biofuel use comprising: at least one mobile vehicle (2) provided with an internal combustion engine (3) configured to provide the power necessary for traction and a single operational tank (4) configured to contain only one type of fuel at a time intended for supplying the internal combustion engine (3); and a fuel system (12) that is separate and independent from the vehicle (2), is arranged in a fixed position in a refueling area accessible by the vehicle (2), and is configured to temporarily connect to the vehicle (2) to supply into the operational tank (4) of the vehicle (2) and without passing through the internal combustion engine (3) biofuel or, alternatively, fossil fuel; the use system (1) is characterized in that the fuel system (12) is configured also to temporarily connect to the vehicle (2) to extract from the operational tank (4) of the vehicle (2) and without passing through the internal combustion engine (3) biofuel or, alternatively, fossil fuel.

2. The use system (1) for biofuel use according to claim 1 , in which the fuel system (12) is configured to: extract from the operational tank (4) of the vehicle (2) fossil fuel so as to empty the operational tank (4) of the vehicle (2) of fossil fuel before supplying into the operational tank (4) of the vehicle (2) biofuel; and extract from the operational tank (4) of the vehicle (2) biofuel so as to empty the operational tank (4) of the vehicle (2) of biofuel before supplying into the operational tank (4) of the vehicle (2) fossil fuel.

3. The use system (1) for biofuel use according to claim 1 or 2, in which the fuel system (12) is configured, before the use of the vehicle (2), to: extract from the operational tank (4) of the vehicle (2) fossil fuel so as to empty the operational tank (4) of the vehicle (2) of fossil fuel; and subsequently supply into the operational tank (4) of the vehicle (2) biofuel so as to fill the operational tank (4) of the vehicle (2) with biofuel.

4. The use system (1) for biofuel use according to claim 1 , 2 or 3, in which the fuel system (12) is configured, at the end of the use of the vehicle (2), to: extract from the operational tank (4) of the vehicle (2) biofuel so as to empty the operational tank (4) of the vehicle (2) of biofuel; and subsequently supply into the operational tank (4) of the vehicle (2) fossil fuel so as to fill the operational tank (4) of the vehicle (2) with fossil fuel.

5. The use system (1) for biofuel use according to claim 4, in which, at the end of the use of the vehicle (2) and after having filled the operational tank (4) of the vehicle (2) with fossil fuel, the internal combustion engine (3) is made to operate for a time at least sufficient to consume all the biofuel remaining in elements that connect the operational tank (4) of the vehicle (2) to injectors of the internal combustion engine (3).

6. The use system (1) for biofuel use according to one of claims 1 to 5, in which: the vehicle (2) comprises a supply port (10) usable for supplying fuel to the operational tank (4) of the vehicle (2) and an extraction port (11) usable for drawing fuel from the operational tank (4) of the vehicle (2); and the fuel system (12) comprises a supply port (15) temporarily connectable to the supply port (10) of the vehicle (2) by means of a first flexible tube (16) and an extraction port (17) temporarily connectable to theextraction port (1 1) of the vehicle (2) by means of a second flexible tube (18).

7. The use system (1) for biofuel use according to claim 6, in which the fuel system (12) comprises: a main tank (13) intended to contain biofuel and preferably provided with a heating device configured to heat the biofuel contained in the main tank (13); and an auxiliary tank (14) intended to contain fossil fuel.

8. The use system (1) for biofuel use according to claim 7, in which the fuel system (12) comprises: a three-way supply valve (19) having two independent inputs and a single outlet; a three-way extraction valve (20) having a single input and two independent outlets; a four-way safety valve (21) having a first input connected to the extraction port (17), a second input, a first outlet connected to the extraction port (17) and a second outlet; a first delivery line (22) that originates from the main tank (13) and ends in a first input of the three- way supply valve (19); a second delivery line (23) that originates from the auxiliary tank (14) and ends in a second input of the three-way supply valve (19); a first return line (28) that originates from a first outlet of the three-way extraction valve (20) and ends in the main tank (13); and a second return line (29) that originates from a second outlet of the three-way extraction valve (20) and ends in the auxiliary tank (14).

9. The use system (1) for biofuel use according to claim 8, in which the fuel system (12) comprises: a third delivery line (30) that originates from the outlet of the three-way supply valve (19) and ends in the second input of the four-way safety valve (21); and a third return line (31) that originates from the second outlet of the four-way safety valve (21) and ends in the input of the three-way extraction valve (20).

10. The use system (1) for biofuel use according to claim 9, in which the fuel system (12) comprises: an interconnection line (32) that connects the third delivery line (30) to the third return line (31); and a circulation pump (33) that is arranged along the interconnection line (32).11 . The use system (1) for biofuel use according to one of claims 1 to 5, in which: the internal combustion engine (3) of the mobile vehicle (2) comprises an exhaust system provided with at least one particulate filter; the operational tank (4) of the vehicle is the only tank that is used for normal operation of the internal combustion engine (3) in the absence of particulate filter regeneration; and the mobile vehicle (2) comprises a regeneration tank that contains exclusively fossil fuel, preferably has a capacity not exceeding 10% of a capacity of the operational tank (4), and is used only for the operation of the internal combustion engine (3) during particulate filter regeneration.

12. A use method for biofuel use and comprising the steps of: providing at least one mobile vehicle (2) provided with an internal combustion engine (3) configured to provide the power necessary for traction and a single operational tank (4) configured to contain only one type of fuel at a time intended for supplying the internal combustion engine (3); temporarily connecting to the vehicle (2) a fuel system (12) separate and independent from the vehicle (2) and arranged in a fixed position in a refueling area accessible by the vehicle (2) to supply into theoperational tank (4) of the vehicle (2) and without passing through the internal combustion engine (3) biofuel or, alternatively, fossil fuel; the use method is characterized by comprising the steps of: temporarily connecting to the vehicle (2) the fuel system (12) to extract from the operational tank (4) of the vehicle (2) and without passing through the internal combustion engine (3) fossil fuel so as to empty the operational tank (4) of the vehicle (2) before supplying into the operational tank (4) of the vehicle (2) of biofuel; and temporarily connecting to the vehicle (2) the fuel system (12) to extract from the operational tank (4) of the vehicle (2) and without passing through the internal combustion engine (3) biofuel so as to empty the operational tank (4) of the vehicle (2) before supplying into the operational tank (4) of the vehicle (2) fossil fuel.

13. The use method according to claim 12 and comprising, before the use of the vehicle (2), the steps of: extracting from the operational tank (4) of the vehicle (2) fossil fuel so as to empty the operational tank (4) of the vehicle (2) of fossil fuel; and subsequently supplying into the operational tank (4) of the vehicle (2) biofuel so as to fill the operational tank (4) of the vehicle (2) with biofuel.

14. The use method according to claim 12 or 13 and comprising, at the end of the use of the vehicle (2), the steps of: extracting from the operational tank (4) of the vehicle (2) biofuel so as to empty the operational tank (4) of the vehicle (2) of biofuel; and subsequently supplying into the operational tank (4) of the vehicle (2) fossil fuel so as to fill the operational tank (4) of the vehicle (2) with fossil fuel.

15. The use method according to claim 14 and comprising the step of, at the end of the use of the vehicle (2) and after having filled the operational tank (4) of the vehicle (2) with fossil fuel, making the internal combustion engine (3) run for a time at least sufficient to consume all the biofuel remaining in elements that connect the operational tank (4) of the vehicle (2) to injectors of the internal combustion engine (3).

16. The use method according to one of claims 12 to 15 and comprising, to perform a regeneration of a particulate filter of the vehicle (2), the steps of: temporarily connecting the vehicle (2) to the fuel system (12) immediately before beginning the regeneration of the particulate filter; and supplying directly to the internal combustion engine (3) of the vehicle (2) and without passing through the operational tank (4) of the vehicle (2) fossil fuel by means of the fuel system (12) to perform the regeneration of the particulate filter.

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