Feeding system for a hydrogen vehicle and related control method

Abstract

Feeding system (1) for a hydrogen user system (24), comprising a tank (2) defining a space (3) configured to house hydrogen transport means, and a gasifier system (21) configured to generate hydrogen in the gaseous state starting from the hydrogen transport means, the tank (2) defining a first outlet opening (5) and a first inlet opening (6) fluidically connected al gasifier system (21) and a membrane (8) configured to divide said space (3) into a first portion (3') and a second portion (3") respectively fluidically connected to the first outlet opening (5) and to the first inlet opening (6).

Description

Technical Field

[0001] The present invention relates to a hydrogen feeding system, in particular to a hydrogen feeding system.

[0002] The present invention applies, preferably but not exclusively, to the field of vehicles. Hereunder, reference will be made to this field of application by way of example.Background Art

[0003] There are known various systems that use hydrogen in vehicle systems, such as the ones disclosed in patent publications US2006090396 A1, US7454898 A, US2016238194 A1, DE29816811 A, DE19916385 A, US2018119882 A1.

[0004] One example is given by engines that use gaseous hydrogen as combustion agent in a combustion cycle. Examples of these systems are those known as HPDI (High Pressure Direct Injection). These engine systems are particularly interesting, as they have a low manufacturing cost and are easier to maintain with respect to fuel cell systems.

[0005] However, these systems require a high injection pressure in order to implement an advance of fuel injection in the flow rates and times / equivalent angle of rotation of the drive shaft so that combustion can be modulated to obtain maximum engine efficiency, while injecting at the end of the compression cycle.

[0006] In the light of the above, a good injection pressure is in the order of 300-350 bar, substantially constant, adapted to allow an adequate compression pressure and an adequate quantity of hydrogen mass injected in a modulated manner into the engine system.

[0007] In order to guarantee the aforesaid pressure the difficulties both of maintaining an adequate mass of hydrogen in the supply tank and of pumping at this pressure are evident.

[0008] However, it is also possible to use medium pressure injection systems (60-70 bar) that utilize injectors for direct injection but that inject at the start of the compression cycle. Clearly, these systems do not allow combustion to be modulated as the mixture in the cylinder is composed of premixed air and hydrogen that are compressed; therefore, it is more difficult to modulate combustion and there are risks of undesirable auto-ignition.

[0009] The same concept of combustion can also be applied to injectors suitable for "port injection", i.e., injection that takes place in the intake manifold (pressure up to 60 bar), although this gives rise to other disadvantages. In particular, the hydrogen in the manifold leads to a reduction in engine power and in case of flashback there is a risk of explosion of the mixture in the manifold.

[0010] Another example of the use of hydrogen is given by fuel cell systems that use a much lower injection pressure (around 5 bar) than that used in the aforesaid injection systems described above.

[0011] Therefore, it is evident that the hydrogen feeding systems would have to be able to provide very different supply pressures depending on the user downstream, whether this is an HPDI or a fuel cell system, without however being too complex and costly and where possible maintaining many common elements.

[0012] Therefore, there is the need to provide a hydrogen feeding system of versatile use for different vehicle systems and which at the same time is safe, has a limited footprint and is cost-effective.

[0013] The object of the present invention is to satisfy the aforesaid requirements in an optimized and cost-effective manner.Summary Of The Invention

[0014] The aforesaid object is achieved by a hydrogen feeding system and a related control method as claimed in the appended claims.Brief Description of the Drawings

[0015] For a better understanding of the present invention there is described below a preferred embodiment, by way of non-limiting example and with reference to the accompanying drawing illustrating a schematic representation of the feeding system according to the invention.Detailed Description of the Invention

[0016] Fig. 1 generically illustrates, with the reference number 1, a hydrogen feeding system according to the invention.

[0017] The feeding system 1 essentially comprises a tank 2 configured to define a space 3 adapted to house hydrogen transport means.

[0018] In particular, the hydrogen transport means is represented by compounds of LOHC (Liquid Organic Hydrogen Carrier) type, i.e., liquid compounds configured to transport hydrogen and release it in the gaseous state through given chemical reactions.

[0019] Consequently, these hydrogen transport means can assume a first chemical condition in which they are filled with hydrogen and a second chemical condition in which they are emptied of hydrogen, having released it in gaseous form.

[0020] The tank 2 defines a first opening 4 configured to allow input of the hydrogen transport means in the aforesaid first condition into the space 3, a second opening 5 configured to allow output of the hydrogen transport means in the aforesaid first condition, a third opening 6 configured to allow input of the hydrogen transport means in the aforesaid second condition into the space 3 and a fourth opening 7 configured to allow output of the hydrogen transport means in the aforesaid second condition.

[0021] Advantageously, the tank 2 comprises a membrane 8, housed movable inside the space 3, configured to separate the hydrogen transport means in the two aforesaid first and second condition.

[0022] In particular, the membrane 8 is connected at its perimeter to the inner surface of the tank 2 so as to divide the space 3 into a first portion 3' housing the hydrogen transport means in the first condition, and hence fluidically communicating with the openings 4 and 5, and a second portion 3" housing the hydrogen transport means in the second condition, and hence fluidically communicating with the openings 6 and 7.

[0023] Advantageously, the membrane 8 is made of a deformable material so as to vary the relative dimension of the portions 3' and 3'' as a function of the volume of hydrogen transport means contained therein.

[0024] The feeding system 1 further comprises a supply system 11 fluidically connected to the first opening 4 and configured to fill the tank 2 with hydrogen transport means in the first condition.

[0025] In particular, the supply system 11 comprises a supply tank 12 and pumping means 13 fluidically interposed between the supply tank 12 and the first opening 4 and configured to pump the hydrogen transport means from the supply tank 12 to the tank 2.

[0026] Advantageously, the supply tank 12 is connected to an opening 14 that allows the hydrogen transport means to be supplied at ambient pressure, for example the filling opening of a vehicle.

[0027] The supply system 11 can also comprise a non-return valve 15 fluidically interposed between the pumping means 13 and the first opening 5 configured to prevent passage of the hydrogen transport means, at high pressure, towards the pumping means 13.

[0028] The feeding system 1 further comprises a gasifier system 21 configured to generate hydrogen in gaseous state starting from the hydrogen transport means in their first condition. Consequently, the gasifier system 21 is fluidically connected to the second and to the third openings 5, 6 and to a hydrogen user system 24, such as a hydrogen engine or a fuel cell system.

[0029] In more detail, the gasifier system 21 comprises a catalyst element 22 fluidically connected to the second and to the third openings 5, 6 and to the hydrogen user system 24 and configured to receive the hydrogen transport means in the first condition and generate, through given chemical reactions dependent on the nature of the hydrogen transport means, the gaseous hydrogen.

[0030] The gaseous hydrogen is directed towards the hydrogen user system 24 while the hydrogen transport means in the second condition are directed towards the third opening 6 in the second portion 3" of the tank 2.

[0031] In particular, the feeding system 1 can comprise filtering means 25 fluidically interposed between the catalyst 22 and the gaseous hydrogen user system 24 to prevent passage of foreign fluid and impurities from the hydrogen towards the hydrogen user system.

[0032] Advantageously, the feeding system 1 can comprise a non-return a valve 28 fluidically interposed between the gasifier system 21 and the filtering means 25 and configured to allow the passage of fluids only towards the latter.

[0033] Advantageously, the feeding system 1 comprises sensor means 29 configured to detect the hydrogen supply pressure required by the hydrogen user system 24. Preferably, these sensor means 29 are pressure sensors fluidically interposed between the filtering means 25 and the hydrogen user system 24.

[0034] Preferably, the feeding system 1 comprises pumping means 26 fluidically interposed between the catalyst 22 and the third opening 6 of the tank 2 to draw the hydrogen transport means in their second condition towards the tank 2.

[0035] Advantageously, the feeding system 1 comprises a non-return valve 27 fluidically interposed between the second opening 5 and the catalyst 22 configured to allow the passage of fluids only towards the latter.

[0036] Advantageously, the gasifier system 21 comprises heating means 23 adapted to increase the temperature of the catalyst 22 to a preset temperature to facilitate the chemical transformation for the production hydrogen.

[0037] These heating means 23 can comprise a heat exchanger that uses the burnt gases or the cooling fluid of a fuel cell output from the hydrogen user system 24, where this is a hydrogen engine or a fuel cell or other vehicle source adapted for the purpose.

[0038] The feeding system 1 further comprises a discharge system 31 fluidically connected to the fourth opening 7 of the tank 2 and configured to allow output of the hydrogen transport means in the second condition towards an outlet 32 for their collection.

[0039] In particular, the discharge system 31 comprises valve means 33 configured to be controlled to allow fluidic communication between the fourth opening and the outlet 32. For example, in the embodiment described the valve means comprise an electrically operated valve, advantageously of ON-OFF type.

[0040] The feeding system 1 advantageously comprises an electronic control unit U comprising processing means and configured to process the data from the sensor means 29 to control the feed of hydrogen transport means towards the gasifier system 21.

[0041] Advantageously, further sensor means can be provided to read the quantity of hydrogen transport means in the tank 2, to indicate their depletion, to check their refilling or the need to empty the tank 2.

[0042] In particular, the electronic control unit U is electronically connected to the pumping means 13, 26 to send an electronic control signal processed starting from the data detected by the sensor means 24.

[0043] Similarly, the electronic control unit U is electronically connected to the valve means 33 to send an electronic control signal processed starting from the data read by the sensor means 24.

[0044] Preferably, the electronic control unit U can be connected to indicator means (not illustrated) adapted to allow viewing of data relating to operation of the feeding system or acoustic / visual warning signals.

[0045] Operation of the embodiment of the feeding system 1 according to the invention described above is as follows.

[0046] In real-time mode or according to preset settings, the pumping means 13, 26 are controlled to pump hydrogen transport means towards the gasifier 21 at a given pressure. As a substantial balance is maintained between the input and output volume in the tank 2 the pressure thus remains constant. In particular, during these passages in volume the portions 3', 3" change volume and the membrane 8 maintains the hydrogen transport means fluidically separated from one another. After entering the gasifier, due to the catalyst 22, if necessary aided by the heating means 23, hydrogen is generated to feed the hydrogen user system 24. Any liquid impurities are filtered by the filter 25. In case of filling, the valve means 33 allow emptying of the second portion 3" of the tank 2 and the opening 14 allows filling of the tank 12, which allows filling of the tank 2.

[0047] In view of the above, the present invention also relates to a control method for a feeding system as described above.

[0048] From the foregoing description, the advantages of a feeding system and a related control method according to the invention are evident. This control method, preferably carried out by the electronic control unit U, comprise the steps of: i) reading data relating to the supply pressure required by the hydrogen user system 24; ii) processing said data to obtain a control signal for said pumping means 13, 26; and iii) controlling said pumping means 13, 26 to obtain the supply pressure detected in step i).

[0049] Due to the system proposed and that uses hydrogen transport means, advantageously of LOHC type, it is possible to prevent mixing with the hydrogen, which remains substantially pure when input into the engine system.

[0050] Consequently, the risks linked to transporting pure hydrogen, in gaseous or liquid form, are reduced.

[0051] Due to the above, it is possible to use standard valve means and pumping means that do not require to operate at very high pressures or at very low temperatures.

[0052] Moreover, it is possible to have a feeding system at variable pressure as a function of the demands of the hydrogen user system.

[0053] Finally, it is evident that modifications and variations may be made to the feeding system and to the related control method according to the present invention, without departing from the scope of protection defined by the claims.

[0054] Clearly, the configuration of the ducts illustrated, the type of valve means and of pumping means may vary.

[0055] Moreover, as said, the filter 25, the heating means 23 and the non-return valves 15, 27 are optional.

[0056] Naturally, as said, different types of hydrogen transport means and catalysts can be used.

Claims

1. Feeding system (1) for a hydrogen user system (24), said feeding system (1) comprising a tank (2) defining a space (3) configured to house hydrogen transport means, said feeding system (1) comprising a gasifier system (21) configured to generate hydrogen in the gaseous state starting from said hydrogen transport means, said tank (2) defining a first outlet opening (5) and a first inlet opening (6) fluidically connected to said gasifier system (21), said tank (2) comprising a membrane (8) configured to divide said space (3) into a first portion (3') and a second portion (3") respectively fluidically connected to the first outlet opening (5) and to the first inlet opening (6), said first portion (3') being configured to house the hydrogen transport means in a first condition and said second portion (3") being configured to house the hydrogen transport means hydrogen in a second condition, characterized in that said hydrogen transport means are of the LOHC (liquid organic hydrogen carrier) type.

2. Feeding system according to claim 1, wherein said membrane (8) is movable and / or deformable.

3. Feeding system according to claim 1 or 2, further comprising pumping means (26) fluidically interposed between said gasifier system (21) and said first inlet opening (6).

4. Feeding system according to one of the preceding claims, wherein said gasifier system (21) comprises a catalyst (22) configured to generate hydrogen by chemically interacting with said hydrogen transport means.

5. Feeding system according to claim 4, wherein said gasifier system (21) comprises heating means (23) configured to heat said catalyst (22).

6. Feeding system according to claim 5, wherein said heating means (23) comprise a heat exchanger using a stream of burnt gases of an internal combustion engine of a vehicle.

7. Feeding system according to one of the preceding claims, comprising filtering means (25) fluidically interposed between said gasifier system (21) and said user system (24).

8. Feeding system according to one of the preceding claims, wherein said tank (2) defines a second inlet opening (4) fluidically connected to said first portion (3') of said tank (2) and to a supply system (11) of said hydrogen transport means comprising pumping means (13) for pumping hydrogen transport means into said tank (2).

9. Feeding system according to one of the preceding claims, wherein said tank (2) defines a second outlet opening (7) fluidically connected to said second portion (3'') of said tank (2) and to a discharge system (31) of said hydrogen transport means.

10. Feeding system according to claim 8 when dependent on claim 3, comprising sensor means (29) configured to detect a quantity relating to a supply pressure of said user system (24) and an electronic control unit (U) configured to acquire and process the data detected by said sensor means (29) and consequently controlling the operation of said pumping means (13, 26).

11. Control method of a feeding system (1) according to claim 10, comprising the steps of: • i) reading data relating to the supply pressure required by the user system (24); • ii) processing said data to obtain a control signal for said pumping means (13, 26); and • iii) controlling said pumping means (13, 26) to obtain the supply pressure detected in step i).

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