Fuel reforming system for vehicle

Abstract

To recover carbon without peeling off a catalyst from a carrier in a fuel reforming system mounted to a vehicle.SOLUTION: A fuel reforming system 1 for a vehicle includes: a reciprocal engine 10 mounted to the vehicle; a decomposition device 50 that decomposes hydrocarbon fuel into carbon and hydrogen gas and stores carbon; a hydrocarbon fuel supply section 30 that supplies hydrocarbon fuel to the decomposition device; a hydrogen gas supply section 40 that supplies hydrogen gas into a cylinder 11; and a carbon recovery section 70 that recovers carbon. The reciprocal engine executes a cycle including a compression stroke, an expansion stroke and re-compression stroke. The decomposition device decomposes hydrocarbon fuel into carbon and hydrogen gas by using heat and pressure of combustion gas in the re-compression stroke. The decompression device includes: a catalyst 52 to which carbon adheres; and a carbon removal mechanism 55 that removes carbon from the catalyst without coming into direct contact with the catalyst. The carbon recovery section recovers the carbon removed from the catalyst.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a fuel reforming system for a vehicle. [Background technology]

[0002] Patent Document 1 describes a cracking device that directly cracks hydrocarbons into carbon and hydrogen.

[0003] This conventional cracking unit includes a reactor containing a catalyst. When a feed gas containing hydrocarbons is fed into the reactor, carbon adheres to the catalyst, and a reactant gas containing hydrogen passes through the reactor. A hydrogen purification unit located downstream of the reactor purifies the hydrogen in the reactant gas, increasing its concentration. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-104521 Summary of the Invention [Problem to be solved by the invention]

[0005] In the field of vehicle technology (for example, four-wheeled automobiles), efforts to achieve carbon neutrality are being sought. To achieve carbon neutrality in vehicles equipped with engines that use hydrocarbon fuels (including gasoline and / or diesel), new technologies for recovering carbon (C) or carbon dioxide (CO2) from hydrocarbon fuels are required, in addition to improving the thermal efficiency of the engine and / or improving exhaust emission performance.

[0006] In vehicles equipped with engines that use hydrocarbon fuel, carbon or carbon dioxide can be captured by (1) capturing carbon dioxide after the hydrocarbon fuel is combusted, or (2) decomposing the hydrocarbon fuel into carbon and hydrogen gas before combustion and capturing the carbon.

[0007] Considering that the captured carbon dioxide or carbon will be stored in the vehicle, (2) is more advantageous than (1) in terms of vehicle fuel efficiency because carbon dioxide is heavier than carbon (carbon is lighter than carbon dioxide). Also, (2) makes it possible to use hydrogen gas as engine fuel. Combusting hydrogen gas has the advantage of not producing carbon oxides due to combustion.

[0008] Therefore, it is conceivable to mount the above-mentioned conventional disassembly device on a vehicle.

[0009] Conventional cracking equipment includes a fluidized-bed reactor vessel. This reactor vessel contains multiple catalyst particles, and the feed gas is ejected upward from the fluidized bed onto the catalyst particles. Carbon adhering to the catalyst particles is removed by suspending the catalyst particles in the feed gas and rubbing the catalyst particles against each other.

[0010] Furthermore, conventional cracking apparatuses are equipped with a catalyst regenerator outside the reactor. The catalyst regenerator is connected to the reactor via a catalyst supply line and a catalyst return line. The catalyst regenerator removes carbon from catalyst particles supplied from the reactor via the catalyst supply line and returns the decarbonized catalyst particles to the reactor via the catalyst return line.

[0011] Catalyst regeneration devices include, for example, rotary pipes that remove carbon from catalyst particles by stirring them and rubbing them against each other, catalyst dissolution devices that remove carbon from catalyst particles by dissolving them, and catalyst conversion devices that remove carbon from catalyst particles by converting the carbon into methane, carbon monoxide, or carbon dioxide using hydrogen, water vapor, and oxygen.

[0012] Conventional cracking devices have the above-mentioned fluidized bed or catalyst regeneration device as a carbon removal mechanism for removing carbon from the catalyst, which inevitably leads to a large size and a complex configuration. Furthermore, conventional cracking devices require a heating device to heat the catalyst. This makes it difficult to install conventional cracking devices on vehicles. Furthermore, in conventional cracking devices, the catalyst is supported on a support.

[0013] Even if it were possible to mount a decomposition device on a vehicle, it would be extremely difficult to remove carbon from the catalyst in the decomposition device mounted on the vehicle without peeling the catalyst off the carrier.

[0014] An object of the present disclosure is to recover carbon in a fuel reforming system installed in a vehicle without peeling the catalyst from the support. [Means for solving the problem]

[0015] A fuel reforming system for a vehicle according to the present disclosure includes a reciprocating engine mounted on the vehicle and having a piston reciprocating within a cylinder, a cracker that decomposes hydrocarbon fuel into carbon and hydrogen gas and stores the carbon, a hydrocarbon fuel supply unit that supplies the hydrocarbon fuel to the cracker, a hydrogen gas supply unit that supplies the hydrogen gas produced by the cracker into the cylinder, and a carbon recovery unit that recovers the carbon produced by the cracker, and the reciprocating engine includes a compression stroke in which the air-fuel mixture containing the hydrogen gas in the cylinder is compressed by the piston rising, and a carbon recovery stroke in which the air-fuel mixture containing the hydrogen gas in the cylinder is recovered. The combustion engine executes a cycle including at least an expansion stroke in which the piston descends due to combustion of the air-fuel mixture, and a recompression stroke in which the combustion gas is compressed as the piston ascends, and the cracker utilizes the heat and pressure of the combustion gas in the recompression stroke to decompose the hydrocarbon fuel supplied from the hydrocarbon fuel supply unit into the carbon and the hydrogen gas, the cracker has a catalyst to which the carbon adheres, and a carbon removal mechanism that removes the carbon from the catalyst without directly contacting the catalyst, and the carbon recovery unit recovers the carbon removed from the catalyst.

[0016] A reciprocating engine includes a compression stroke, an expansion stroke, and then a recompression stroke in which the combustion gases are compressed by the rising piston. A hydrocarbon fuel supply supplies hydrocarbon fuel to the cracker.

[0017] The cracker utilizes the heat and pressure of the combustion gases from the recompression process to decompose the hydrocarbon fuel into carbon and hydrogen gas. The cracker can efficiently decompose the hydrocarbon fuel. The carbon is stored in the cracker.

[0018] The hydrogen gas supply unit supplies the hydrogen gas produced in the cracker as fuel into the cylinders of the reciprocating engine. The reciprocating engine operates by burning the hydrogen gas. No carbon oxides are produced by combustion. The reciprocating engine can supply heat and pressure to the cracker for cracking hydrocarbon fuel while outputting driving power to run the vehicle.

[0019] The fuel reforming system can achieve carbon neutrality. Because the fuel reforming system utilizes the heat and pressure generated by the reciprocating engine, a separate dedicated device is not required to generate the heat and / or pressure required to decompose hydrocarbon fuel. The fuel reforming system is useful as an on-board system installed in a vehicle.

[0020] The decomposer further includes a catalyst to which carbon adheres and a carbon removal mechanism that removes carbon from the catalyst without directly contacting the catalyst. Because the carbon removal mechanism does not directly contact the catalyst, carbon can be removed from the catalyst without peeling the catalyst from the support. The carbon recovery unit can then recover the carbon removed from the catalyst.

[0021] As described above, in a fuel reforming system mounted on a vehicle, carbon can be recovered without peeling the catalyst from the carrier.

[0022] In one embodiment, the carbon removal mechanism includes a vibrator that applies vibration to the catalyst without directly contacting the catalyst.

[0023] According to this configuration, the vibrator of the carbon removal mechanism applies vibration to the catalyst without directly contacting the catalyst, thereby making it possible to remove carbon from the catalyst without peeling the catalyst from the carrier.

[0024] In one embodiment, the decomposition vessel has a support that supports the catalyst, and the vibrator is disposed on the opposite side of the catalyst across the support, and the vibrator applies vibration to the catalyst via the support.

[0025] According to this configuration, the vibrator is disposed on the opposite side of the catalyst with the support interposed therebetween, so that the vibrator does not come into direct contact with the catalyst.

[0026] In one embodiment, the support is cylindrical and supports the catalyst on its inner surface, and the vibrator is held on the outer surface side of the support.

[0027] According to this configuration, the catalyst is supported on the inner surface of a cylindrical support and the vibrator is held on the outer surface of the cylindrical support, thereby making it possible to prevent the vibrator from coming into direct contact with the catalyst with a simple configuration.

[0028] In one embodiment, the carbon removal mechanism includes a catechin supply device that supplies a liquid containing catechin to the catalyst.

[0029] According to this configuration, the catechin supply device of the carbon removal mechanism supplies the liquid containing catechin to the catalyst, so that carbon can be removed from the catalyst by the action of the catechin without coming into direct contact with the catalyst.

[0030] In one embodiment, the decomposition vessel has a support that supports the catalyst and a liquid separation membrane that is provided on the support adjacent to the catalyst, and the catechin supply device supplies the liquid to the catalyst through the liquid separation membrane.

[0031] According to this configuration, the liquid containing catechins can be easily supplied to the catalyst by passing through the liquid separation membrane adjacent to the catalyst.

[0032] In one embodiment, the carbon recovery unit includes a discharge path through which the carbon removed from the catalyst is discharged, and a discharge valve that opens and closes the discharge path.

[0033] According to this configuration, the carbon can be easily collected by the discharge passage and the discharge valve in the carbon collection section.

[0034] In one embodiment, the vehicle fuel reforming system operates in a carbon removal mode in which the exhaust valve closes the exhaust passage and the carbon is removed from the catalyst by the carbon removal mechanism, and in a carbon discharge mode in which the exhaust valve opens the exhaust passage and the carbon is discharged into the exhaust passage using the combustion gas.

[0035] With this configuration, it is possible to suitably use the removal of carbon from the catalyst by the carbon removal mechanism in the carbon removal mode and the discharge of carbon by the carbon recovery unit using combustion gas in the carbon discharge mode. [Effects of the Invention]

[0036] According to the present disclosure, in a fuel reforming system mounted on a vehicle, carbon can be recovered without peeling the catalyst from the support. [Brief explanation of the drawings]

[0037] [Figure 1] FIG. 1 shows a fuel reforming system. [Figure 2]FIG. 2 is a front cross-sectional view of the decomposer and carbon recovery unit according to the first embodiment. [Figure 3] FIG. 3 shows a side cross-sectional view of the decomposer according to the first embodiment. [Figure 4] FIG. 4 shows the hydrogen gas supply section. [Figure 5] Figure 5 shows the control system. [Figure 6] FIG. 6 shows each step of a six-stroke cycle according to the first embodiment. [Figure 7] FIG. 7 shows carbon adhered to the catalyst on the inner surface of the support in the cracker according to the first embodiment. [Figure 8] FIG. 8 shows the carbon recovery mechanism in the normal operation mode, the carbon removal mode, and the carbon discharge mode. [Figure 9] FIG. 9 shows the inner surface of the support in the decomposer according to the second embodiment. [Figure 10] FIG. 10 shows each stroke of a modified four-stroke cycle according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0038] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0039] First Embodiment (Fuel reforming system) A fuel reforming system 1 for a vehicle according to a first embodiment will be described. FIG. 1 shows the fuel reforming system 1. The fuel reforming system 1 is mounted on a vehicle. The vehicle may be, for example, a four-wheeled vehicle or a two-wheeled vehicle. The fuel reforming system 1 decomposes hydrocarbon fuel (CH fuel) into carbon (C) and hydrogen gas (H gas) using a decomposer 50, which will be described later. The carbon is stored in the decomposer 50. The hydrogen gas is used as fuel for a reciprocating engine 10. The fuel reforming system 1 makes the vehicle carbon neutral.

[0040] The vehicle fuel reforming system 1 includes a reciprocating engine 10, a hydrocarbon fuel supply unit 30, a hydrogen gas supply unit 40, a cracker 50, a carbon recovery unit 70, a control system 80, and a hydrogen gas passage 90.

[0041] (reciprocating engine) The reciprocating engine 10 is mounted on a vehicle and includes a cylinder 11, a piston 12, an intake port 13, an intake valve 14, an exhaust port 15, an exhaust valve 16, a reforming port 17, and an on-off valve 18.

[0042] There are multiple cylinders 11. The multiple cylinders 11 are lined up, for example, in the direction in which the crankshaft of the reciprocating engine 10 extends. A piston 12 is housed in each cylinder 11. The piston 12 reciprocates within the cylinder 11. The piston 12 is connected to the crankshaft via a connecting rod. The connecting rod converts the reciprocating motion of the piston 12 into rotation of the crankshaft. The crankshaft is connected to the drive wheels via a transmission. The reciprocating engine 10 outputs driving force for running the vehicle. The reciprocating engine 10 may also be used as a driving source for driving a generator.

[0043] The intake ports 13 communicate with the cylinders 11. One or more intake ports 13 are connected to each cylinder 11. For example, two intake ports 13 are connected to each cylinder 11. The intake ports 13 are connected to an intake pipe. Intake air is introduced into the cylinders 11 through the intake ports 13. The intake air includes fresh air. The intake air may also include EGR (Exhaust Gas Recirculation) gas. The intake valves 14 are poppet valves that open and close the intake ports 13. When the intake valves 14 open, the intake air is introduced into the cylinders 11 through the intake ports 13.

[0044] The exhaust port 15 communicates with the cylinder 11. One or more exhaust ports 15 are connected to each cylinder 11. For example, one exhaust port 15 may be connected to each cylinder 11. The exhaust port 15 is connected to an exhaust pipe. Exhaust gas is discharged from inside the cylinder 11 to outside the cylinder 11 through the exhaust port 15. The exhaust valve 16 is a poppet valve that opens and closes the exhaust port 15. When the exhaust valve 16 opens, exhaust gas is discharged from inside the cylinder 11 to outside the cylinder 11 through the exhaust port 15.

[0045] The reforming port 17 is in communication with the cylinder 11. At least one reforming port 17 is connected to each cylinder 11. For example, one reforming port 17 may be connected to each cylinder 11. The on-off valve 18 is a poppet valve and opens and closes the reforming port 17.

[0046] A typical reciprocating engine has two intake ports and two exhaust ports per cylinder. One of the two exhaust ports may be converted into a reforming port 17. Alternatively, one of the two intake ports may be converted into a reforming port 17. In this example, the reciprocating engine 10 has two intake ports 13, one exhaust port 15, and one reforming port 17 per cylinder 11. Note that in FIG. 1, the exhaust port 15 and the reforming port 17 are depicted at offset positions for ease of understanding.

[0047] The reciprocating engine 10 has an intake valve train 21, an exhaust valve train 22, and a reforming valve train 23 (see FIG. 5). The intake valve train 21 opens and closes the intake valve 14. The exhaust valve train 22 opens and closes the exhaust valve 16. The reforming valve train 23 opens and closes the on-off valve 18.

[0048] The intake valve train 21 and the exhaust valve train 22 have intake camshafts and exhaust camshafts mechanically connected to the intake valve 14 and the exhaust valve 16, and can continuously change the valve timing of the intake valve 14 and the exhaust valve 16 (so-called S-VT (Sequential-Valve Timing)). The intake valve train 21 and the exhaust valve train 22 can continuously change the valve lift of the intake valve 14 and the exhaust valve 16 (so-called CVVL (Continuously Variable Valve Lift)). The intake valve train 21 and the exhaust valve train 22 can employ known hydraulic or electric mechanisms.

[0049] The reforming valve train 23 has, for example, a reforming camshaft mechanically connected to the on-off valve 18. The reforming valve train 23 opens the on-off valve 18 twice during one cycle (see FIG. 6). The reforming valve train 23 can stop the on-off valve 18 from opening or closing. A known hydraulic or electric mechanism can be used as a valve stop mechanism that stops the on-off valve 18 from opening or closing. The valve stop mechanism may be incorporated, for example, into a rocker arm interposed between the reforming camshaft and the on-off valve 18. The valve stop mechanism may be incorporated into a lash adjuster that supports the rocker arm. The on-off valve 18 may be mechanically connected to the intake camshaft or the exhaust camshaft.

[0050] The reciprocating engine 10 has an intake port injector 24, a reforming port injector 25, and a hydrogen injector 26. The injection holes of the intake port injector 24 face into the intake port 13. The intake port injector 24 injects hydrocarbon fuel into the intake port 13. The injection holes of the reforming port injector 25 face into the reforming port 17. The reforming port injector 25 injects hydrocarbon fuel into the reforming port 17. The injection holes of the hydrogen injector 26 face into the cylinder 11. The hydrogen injector 26 injects hydrogen gas into the cylinder 11.

[0051] It should be noted that an injector that injects hydrocarbon fuel may face the inside of the cylinder 11 , and a hydrogen injector that injects hydrogen gas may face the inside of the intake port 13 .

[0052] The reciprocating engine 10 has a spark plug 27 (see FIG. 5). The spark plug 27 faces the inside of the cylinder 11. The spark plug 27 ignites the air-fuel mixture in the cylinder 11.

[0053] (Hydrocarbon fuel supply unit and hydrogen gas supply unit) The hydrocarbon fuel supply unit 30 is mounted on the vehicle. The hydrocarbon fuel supply unit 30 is connected to the intake port injector 24. The hydrocarbon fuel supply unit 30 is also connected to the reforming port injector 25. The hydrocarbon fuel supply unit 30 selectively supplies hydrocarbon fuel to the intake port injector 24 and the reforming port injector 25.

[0054] The hydrocarbon fuel supply unit 30 has a fuel tank that stores hydrocarbon fuel and a fuel pump that pumps the hydrocarbon fuel. The hydrocarbon fuel is stored in the fuel tank. The hydrocarbon fuel is, for example, gasoline. The hydrocarbon fuel may also be diesel fuel. The hydrocarbon fuel may also be other fuels.

[0055] As described above, the hydrocarbon fuel supply unit 30 supplies hydrocarbon fuel to the reforming port injector 25. The reforming port injector 25 supplies hydrocarbon fuel into the reforming port 17. The hydrocarbon fuel supplied into the reforming port 17 is supplied to the cracker 50, which will be described later. In summary, the hydrocarbon fuel supply unit 30 supplies hydrocarbon fuel to the cracker 50 through the reforming port injector 25 and the reforming port 17.

[0056] The hydrogen gas supply unit 40 is mounted on the vehicle. The hydrogen gas supply unit 40 is connected to the hydrogen injector 26. The hydrogen gas supply unit 40 supplies hydrogen gas to the hydrogen injector 26. As described above, the hydrogen gas is hydrogen gas decomposed from a hydrocarbon fuel. The configuration of the hydrogen gas supply unit 40 will be described later.

[0057] (decomposer) The cracker 50 is mounted on the vehicle. The cracker 50 is connected to the reforming port 17. The cracker 50 is attached to each cylinder 11. The cracker 50 may be common to multiple cylinders 11. The cracker 50 is a so-called membrane reactor.

[0058] Fig. 2 is a front cross-sectional view of cracker 50. Fig. 3 is a side cross-sectional view of cracker 50 taken along line III. Cracker 50 has a support 51, a catalyst 52, a hydrogen separation membrane 53, a case 54, and a carbon removal mechanism 55.

[0059] The support 51 is formed in a cylindrical shape. The cylindrical support 51 includes an outer surface 51a facing the outer periphery and an inner surface 51b facing the inner periphery. The support 51 is made of, for example, ceramic. The support 51 may also be made of, for example, aluminum oxide. The support 51 may also be made of other materials.

[0060] The catalyst 52 is supported on the inner surface 51b of the cylindrical support 51. In other words, the cylindrical support 51 supports the catalyst 52 on the inner surface 51b. More specifically, the catalyst 52 is applied to a part or all of the inner surface 51b of the cylindrical support 51. Carbon from the hydrocarbon fuel adheres to the catalyst 52. The catalyst 52 is made of, for example, a Ni-Al-Fe alloy. Note that various catalysts can be used as the catalyst 52 as long as they can adhere carbon. Carbon adheres to the catalyst 52 through a chemical reaction.

[0061] The hydrogen separation membrane 53 is formed in a cylindrical shape. The cylindrical hydrogen separation membrane 53 includes an outer surface 53a facing the outer periphery and an inner surface 53b facing the inner periphery. The hydrogen separation membrane 53 is disposed inside the support 51 (inside the inner surface 51b of the support 51). The outer diameter of the hydrogen separation membrane 53 is smaller than the inner diameter of the support 51. A gap A is formed between the inner surface 51b of the support 51 and the outer surface 53a of the hydrogen separation membrane 53. Of the hydrocarbon fuels, only hydrogen gas permeates the hydrogen separation membrane 53. The hydrogen separation membrane 53 is made of, for example, a Pd alloy. However, the hydrogen separation membrane 53 is not limited to a Pd alloy membrane.

[0062] Hereinafter, the right side of FIG. 2 will be referred to as one side, and the left side of FIG. 2 will be referred to as the other side. The direction from one side to the other side is the horizontal direction. The upper side of FIG. 2 will be simply referred to as the upper side, and the lower side of FIG. 2 will be simply referred to as the lower side. One end of the support 51 is open. One end of the support 51 is connected to (communicates with) the reforming port 17. The opening at one end of the support 51 faces the reforming port 17. The other end of the support 51 is open. The other end of the support 51 is connected to (communicates with) the carbon recovery section 70 described below. The opening at the other end of the support 51 faces the carbon recovery section 70.

[0063] One end of the hydrogen separation membrane 53 is closed. One end of the hydrogen separation membrane 53 is recessed toward the other side from one end of the support 51. The other end of the hydrogen separation membrane 53 protrudes toward the other side from the other end of the support 51. The other end of the hydrogen separation membrane 53 is open. The other end of the hydrogen separation membrane 53 is connected (communicates) with a cylindrical hydrogen gas passage 90. The outer diameter of the other end of the hydrogen separation membrane 53 fits into the inner diameter of one end of the hydrogen gas passage 90. The opening at the other end of the hydrogen separation membrane 53 faces the hydrogen gas passage 90.

[0064] The hydrogen gas passage 90 connects the hydrogen separation membrane 53 and the hydrogen injector 26. A hydrogen gas supply unit 40, which will be described later, is connected to the middle of the hydrogen gas passage 90 (see FIG. 4).

[0065] The case 54 is formed in a substantially cylindrical shape. The case 54 includes a cylindrical tubular portion 54a and inward extending portions 54b extending inward from one end and the other end of the tubular portion 54a. The tubular portion 54a of the case 54 covers the outer surface 51a of the support 51. The inward extending portions 54b of the case 54 cover one end face and the other end face of the support 51. The case 54 holds the support 51 and the hydrogen separation membrane 53.

[0066] The hydrocarbon fuel is introduced into the support 51 (inside the inner surface 51b) from an opening at one end of the support 51 through the reforming port 17 together with combustion gas, which will be described later (see the black arrow in FIG. 2). The hydrocarbon fuel flows from one side to the other through a gap A between the inner surface 51b of the support 51 and the outer surface 53a of the hydrogen separation membrane 53.

[0067] Of the hydrocarbon fuel flowing through gap A, carbon adheres to catalyst 52 on inner surface 51b of support 51. Of the hydrocarbon fuel flowing through gap A, hydrogen gas passes through hydrogen separation membrane 53 from the outside to the inside and is introduced inside hydrogen separation membrane 53 (inside inner surface 53b) (see the outline arrow in FIG. 2). The hydrogen gas flows inside hydrogen separation membrane 53 (inside inner surface 53b) to the other side and is supplied to hydrogen gas supply unit 40, which will be described later, through hydrogen gas passage 90.

[0068] Hydrocarbon fuel is supplied from the hydrocarbon fuel supply unit 30 to the cracker 50 via the reforming port injector 25 and the reforming port 17. The cracker 50 decomposes the hydrocarbon fuel into carbon and hydrogen gas by causing the carbon to adhere to the catalyst 52 and the hydrogen gas to pass through the hydrogen separation membrane 53. The cracker 50 generates carbon and hydrogen gas, which are decomposed from each other.

[0069] The cracker 50 stores carbon. Specifically, the carbon attached to the catalyst 52 on the inner surface 51b of the support 51 remains in the gap A between the inner surface 51b of the support 51 and the outer surface 53a of the hydrogen separation membrane 53.

[0070] The decomposition of hydrocarbon fuels, for example the decomposition of isooctane, is represented by the following chemical reaction: iC8H18(g)=8C(s)+9H2.

[0071] (carbon removal mechanism) The carbon removal mechanism 55 includes a vibrator 56. The vibrator 56 converts high-frequency power into vibration. The vibrator 56 may be of an electrostrictive type or a magnetostrictive type, for example. The electrostrictive type expands and contracts when a voltage is applied. The magnetostrictive type expands and contracts when a magnetic field is applied. The vibrator 56 generates ultrasonic vibrations.

[0072] The vibrator 56 is fixed to the outer surface of the cylindrical portion 54a of the case 54. That is, the vibrator 56 is held on the outer surface 51a side of the support 51, with the cylindrical portion 54a of the case 54 sandwiched between them. The catalyst 52 is provided on the inner surface 51b of the support 51. The cylindrical portion 54a of the case 54 and the support 51 are interposed between the vibrator 56 and the catalyst 52. The vibrator 56 is disposed on the opposite side of the catalyst 52, with the cylindrical portion 54a of the case 54 and the support 51 sandwiched between them.

[0073] The oscillator 56 is not in direct contact with the catalyst 52. "Direct contact" means that two objects are in direct physical contact with each other. The oscillator 56 applies vibrations to the catalyst 52 via the cylindrical portion 54a of the case 54 and the support 51. The oscillator 56 of the carbon removal mechanism 55 applies vibrations to the catalyst 52 without coming into direct contact with it. The oscillator 56 of the carbon removal mechanism 55 removes carbon from the catalyst 52 without coming into direct contact with it.

[0074] (Hydrogen gas supply unit) 4 shows the hydrogen gas supply unit 40. Hereinafter, the upstream side in the flow of hydrogen gas (decomposer 50 side) will be simply referred to as the upstream side, and the downstream side in the flow of hydrogen gas (hydrogen injector 26 side) will be simply referred to as the downstream side.

[0075] The hydrogen gas supply unit 40 is mounted on a vehicle. The hydrogen gas supply unit 40 is provided midway through a hydrogen gas passage 90. The upstream end of the hydrogen gas passage 90 is connected to a cracker 50. As described above, the cracker 50 generates hydrogen gas. The downstream end of the hydrogen gas passage 90 is connected to a hydrogen injector 26. Hydrogen gas is supplied to the hydrogen gas supply unit 40 from the cracker 50. The hydrogen gas supply unit 40 supplies the hydrogen gas to the hydrogen injector 26. The hydrogen injector 26 injects the hydrogen gas into the cylinder 11.

[0076] In summary, the hydrogen gas supply unit 40 supplies the hydrogen gas produced by the cracker 50 into the cylinder 11 through the hydrogen gas passage 90 and the hydrogen injector 26 .

[0077] The hydrogen gas supply unit 40 may be common to multiple cylinders 11. Alternatively, a hydrogen gas supply unit 40 may be provided for each cylinder 11. The hydrogen gas supply unit 40 includes a first tank 41, a second tank 42, a bypass passage 43, a first switching valve 44, a second switching valve 45, and a hydrogen pump 46.

[0078] The first tank 41 is connected to the hydrogen gas passage 90. The first tank 41 stores the hydrogen gas supplied from the cracker 50.

[0079] The bypass passage 43 is configured as a part of the hydrogen gas passage 90, and bypasses the first tank 41. The first switching valve 44 is connected to the hydrogen gas passage 90 upstream of the first tank 41. The second switching valve 45 is connected to the hydrogen gas passage 90 downstream of the first tank 41. The first switching valve 44 and the second switching valve 45 receive control signals from a controller 81, which will be described later, and switch the hydrogen gas flow path between the first tank 41 side and the bypass passage 43 side.

[0080] The hydrogen pump 46 is connected to the hydrogen gas passage 90 downstream of the second switching valve 45. The hydrogen pump 46 increases the pressure of the hydrogen gas. The second tank 42 is connected to the hydrogen gas passage 90 below the hydrogen pump 46. The second tank 42 is located in the hydrogen gas passage 90 between the hydrogen pump 46 and the hydrogen injector 26. The second tank 42 stores high-pressure hydrogen gas.

[0081] The pressure of the first tank 41 is lower than the pressure of the second tank 42. The low-pressure first tank 41 lowers the pressure on the secondary side of the hydrogen separation membrane 53 (the pressure inside the inner surface 53b of the hydrogen separation membrane 53) below the pressure on the primary side of the hydrogen separation membrane 53 (the pressure in the gap A between the inner surface 51b of the support 51 and the outer surface 53a of the hydrogen separation membrane 53). The low-pressure first tank 41 increases the pressure difference between the primary and secondary sides of the hydrogen separation membrane 53. The large pressure difference promotes permeation of hydrogen gas through the hydrogen separation membrane 53. The hydrogen gas generated in the gap A (primary side) between the inner surface 51b of the support 51 and the outer surface 53a of the hydrogen separation membrane 53 quickly permeates inside the inner surface 53b of the hydrogen separation membrane 53 (secondary side), thereby promoting the cracking reaction of the hydrocarbon fuel in the cracker 50.

[0082] The combination of the first tank 41 and the heat and pressure of the combustion gas in the recompression stroke S4, which will be described later, significantly accelerates the cracking reaction of the hydrocarbon fuel in the cracker 50. Acceleration of the cracking reaction of the hydrocarbon fuel makes it possible to ensure the amount of hydrogen gas necessary to operate the reciprocating engine 10, even if the cracker 50 is small.

[0083] Similarly, when the hydrogen gas flow path is switched to the bypass passage 43 side, the pressure on the secondary side of the hydrogen separation membrane 53 decreases due to the operation of the hydrogen pump 46. The high-pressure second tank 42 can stably supply high-pressure hydrogen gas to the hydrogen injector 26. The hydrogen injector 26 can inject hydrogen gas into the cylinder 11 at a timing near the compression top dead center when the pressure inside the cylinder 11 is high. The hydrogen pump 46 makes it possible to supply high-pressure hydrogen gas to the hydrogen injector 26 while maintaining a low pressure in the first tank 41.

[0084] (Carbon Recovery Department) 2 is a front cross-sectional view of the carbon recovery unit 70. The carbon recovery unit 70 is mounted on a vehicle. The carbon recovery unit 70 has a housing 71, a discharge passage 72, and a discharge valve 73.

[0085] The housing 71 includes a cylindrical portion 71a and a lid portion 71b. The cylindrical portion 71a is cylindrical. One end of the cylindrical portion 71a of the housing 71 is connected to the other end of the support 51 via the inner extension portion 54b of the case 54. The other end of the hydrogen separation membrane 53 and one end of a hydrogen gas passage 90 are housed inside the cylindrical portion 71a of the housing 71. A discharge hole 74 is formed in the lower portion of the cylindrical portion 71a of the housing 71. The lid portion 71b of the housing 71 covers the opening at the other end of the cylindrical portion 71a. A through-hole is formed in the lid portion 71b of the housing 71. The hydrogen gas passage 90 passes through the through-hole in the lid portion 71b of the housing 71.

[0086] The discharge path 72 includes a cylindrical portion 72a and a lid portion 72b. The cylindrical portion 72a of the discharge path 72 is cylindrical and extends vertically. The upper end of the cylindrical portion 72a of the discharge path 72 is connected to a discharge hole 74 provided in the lower part of the cylindrical portion 71a of the housing 71. In the discharge path 72, the lid portion 72b covers the lower end of the cylindrical portion 72a. Carbon removed from the catalyst 52 of the cracker 50 is discharged into the discharge path 72. The carbon discharged into the discharge path 72 is accumulated in the discharge path 72.

[0087] The discharge valve 73 opens and closes the discharge path 72. More specifically, the discharge valve 73 opens and closes a discharge hole 74 (a connection between the housing 71 and the discharge path 72) at the bottom of the cylindrical portion 71a of the housing 71. When the discharge valve 73 closes the discharge path 72, the internal space of the discharge path 72 does not communicate with the internal space of the housing 71. When the discharge valve 73 opens the discharge path 72, the internal space of the discharge path 72 communicates with the internal space of the housing 71.

[0088] As will be described in detail later, the carbon recovery unit 70 recovers the carbon generated in the decomposer 50. In particular, the carbon recovery unit 70 recovers the carbon removed from the catalyst 52 of the decomposer 50. The carbon discharged into the discharge path 72 of the carbon recovery unit 70 is removed from the vehicle, for example, when the vehicle is brought in for maintenance. The removed carbon can be reused as a recycled product.

[0089] (Control System) 5 is a block diagram of a control system 80. The control system 80 includes a controller 81. The controller 81 is made up of hardware such as a processor, memory, and interface, and software such as a database and control program.

[0090] The rotation speed sensor 82 is electrically connected to the controller 81. The rotation speed sensor 82 is attached to the reciprocating engine 10. The rotation speed sensor 82 outputs a measurement signal corresponding to the rotation speed of the crankshaft to the controller 81. The controller 81 can grasp the rotation speed of the reciprocating engine 10 based on the measurement signal of the rotation speed sensor 82.

[0091] An accelerator position sensor 83 is electrically connected to the controller 81. The accelerator position sensor 83 is attached to the accelerator pedal. The accelerator position sensor 83 outputs a signal corresponding to the depression amount of the accelerator pedal to the controller 81. The controller 81 can grasp the required load of the reciprocating engine 10 based on the measurement signal of the accelerator position sensor 83.

[0092] The knock sensor 84 is electrically connected to the controller 81. The knock sensor 84 is attached to the reciprocating engine 10. When knocking occurs in the reciprocating engine 10, the knock sensor 84 outputs a knock detection signal to the controller 81. The controller 81 can determine the occurrence of knocking based on the knock detection signal.

[0093] A tank pressure sensor 85 is electrically connected to the controller 81. The tank pressure sensor 85 is attached to the second tank 42 of the hydrogen gas supply unit 40. The tank pressure sensor 85 outputs a signal corresponding to the amount of hydrogen gas in the second tank 42 to the controller 81. The controller 81 can determine the amount of hydrogen gas that can be supplied to the cylinder 11 based on the signal from the tank pressure sensor 85.

[0094] The intake valve train 21, the exhaust valve train 22, and the reforming valve train 23 are electrically connected to a controller 81. The controller 81 outputs control signals to the intake valve train 21, the exhaust valve train 22, and the reforming valve train 23 depending on the operating state of the reciprocating engine 10. The intake valve train 21 changes the valve timing and / or valve lift of the intake valve 14 based on the control signal from the controller 81. The exhaust valve train 22 changes the valve timing and / or valve lift of the exhaust valve 16 based on the control signal from the controller 81. The reforming valve train 23 switches the on-off valve 18 between open and closed states based on the control signal from the controller 81.

[0095] The intake port injector 24, the reforming port injector 25, and the hydrogen injector 26 are electrically connected to a controller 81. The controller 81 outputs control signals to the intake port injector 24, the reforming port injector 25, and the hydrogen injector 26. The intake port injector 24 injects a predetermined amount of hydrocarbon fuel into the intake port 13 at a predetermined timing based on the control signal from the controller 81. The reforming port injector 25 injects a predetermined amount of hydrocarbon fuel into the reforming port 17 at a predetermined timing based on the control signal from the controller 81. The hydrogen injector 26 injects a predetermined amount of hydrogen gas into the cylinder 11 at a predetermined timing based on the control signal from the controller 81.

[0096] The spark plug 27 is electrically connected to the controller 81. The spark plug 27 is attached to the reciprocating engine 10. The controller 81 outputs a control signal to the spark plug 27. Based on the control signal from the controller 81, the spark plug 27 ignites the air-fuel mixture in the cylinder 11 at a predetermined timing.

[0097] The hydrogen gas supply unit 40 is electrically connected to a controller 81. The controller 81 outputs control signals to the first switching valve 44, the second switching valve 45 and the hydrogen pump 46 in the hydrogen gas supply unit 40.

[0098] The vibrator 56 of the carbon removal mechanism 55 is electrically connected to the controller 81. The controller 81 outputs a control signal to the vibrator 56 of the carbon removal mechanism 55. The vibrator 56 of the carbon removal mechanism 55 applies vibration to the catalyst 52 or stops the vibration based on the control signal from the controller 81.

[0099] The discharge valve 73 of the carbon recovery unit 70 is electrically connected to the controller 81. The controller 81 outputs a control signal to the discharge valve 73 of the carbon recovery unit 70. The discharge valve 73 of the carbon recovery unit 70 opens and closes the discharge path 72 of the carbon recovery unit 70 based on the control signal from the controller 81.

[0100] (6-stroke cycle) The reciprocating engine 10 executes a six-stroke cycle in order for the cracker 50 to crack hydrocarbon fuel. Figure 6 shows each stroke of the six-stroke cycle. The six-stroke cycle includes an intake stroke S1, a compression stroke S2, an expansion stroke S3, a recompression stroke S4, a re-expansion stroke S5, and an exhaust stroke S6.

[0101] During the intake stroke S1, intake air is introduced into the cylinder 11 as the piston 12 descends. During the intake stroke S1, the intake valve 14 opens. The intake air is introduced into the cylinder 11 through the intake port 13. The intake air includes fresh air. The intake air may also include EGR gas. This EGR gas is external EGR gas that has been recirculated to the intake pipe through the EGR passage. During the intake stroke S1, the exhaust valve 16 may open. When the exhaust valve 16 opens, exhaust gas is introduced into the cylinder 11 through the exhaust port 15. The exhaust gas introduced into the cylinder 11 is internal EGR gas. The opening / closing valve 18 of the reforming port 17 is closed.

[0102] The hydrogen injector 26 (hydrogen gas supply unit 40) injects (supplies) hydrogen gas into the cylinder 11 during the intake stroke S1. The hydrogen injector 26 may inject hydrogen gas during the compression stroke S2 ​​following the intake stroke S1. The hydrogen injector 26 may inject hydrogen gas during the period from the intake stroke S1 to the compression stroke S2. A mixture of hydrogen gas and intake air is generated in the cylinder 11.

[0103] If there is a shortage of hydrogen gas, the intake port injector 24 may inject hydrocarbon fuel into the intake port 13 during the intake stroke S1 to make up for the shortage. If there is no hydrogen gas, the intake port injector 24 may inject hydrocarbon fuel into the intake port 13 during the intake stroke S1 instead of the hydrogen injector 26. If there is a shortage of hydrogen gas to be supplied into the cylinder 11, the intake port injector 24 injects hydrocarbon fuel, thereby ensuring the required fuel amount for the reciprocating engine 10. The reciprocating engine 10 can be operated using hydrocarbon fuel or both hydrocarbon fuel and hydrogen gas.

[0104] In the compression stroke S2, the air-fuel mixture containing hydrogen gas in the cylinder 11 is compressed by the upward movement of the piston 12. In the compression stroke S2, the intake valve 14, the exhaust valve 16, and the on-off valve 18 are all closed.

[0105] The spark plug 27 ignites the air-fuel mixture in the cylinder 11 near the top dead center of the compression stroke. The air-fuel mixture begins to burn. During the expansion stroke S3, the piston 12 descends due to the combustion of the air-fuel mixture. During the expansion stroke S3, the intake valve 14, exhaust valve 16, and on-off valve 18 are all closed.

[0106] In the recompression stroke S4, the piston 12 rises, compressing the combustion gas in the cylinder 11. In the recompression stroke S4, the on-off valve 18 opens. In the recompression stroke S4, the compressed combustion gas is introduced into the cracker 50 through the reforming port 17. In the recompression stroke S4, the reforming port injector 25 injects hydrocarbon fuel into the reforming port 17. The hydrocarbon fuel is introduced into the cracker 50 together with the combustion gas. In detail, in the recompression stroke S4, the hydrocarbon fuel is supplied from the hydrocarbon fuel supply unit 30 to the cracker 50 via the reforming port injector 25 and the reforming port 17, and the combustion gas is supplied from inside the cylinder 11 to the cracker 50 via the reforming port 17.

[0107] In the recompression step S4, the hydrocarbon fuel is decomposed into carbon and hydrogen gas in the cracker 50 by the heat of the combustion gas and the catalyst 52. The carbon adheres to the catalyst 52 and is stored in the cracker 50. In the recompression step S4, the hydrogen gas permeates the hydrogen separation membrane 53 in the cracker 50 due to the pressure of the combustion gas and is sent to the hydrogen gas supply unit 40 via the hydrogen gas passage 90.

[0108] Since the high pressure of the combustion gas in the recompression step S4 is applied to the cracker 50 (more specifically, the gap A between the inner surface 51b of the support 51 and the outer surface 53a of the hydrogen separation membrane 53), the hydrogen gas generated in the cracker 50 (gap A) quickly permeates the hydrogen separation membrane 53 and is sent to the inside of the hydrogen separation membrane 53 (more specifically, inside the inner surface 53b of the hydrogen separation membrane 53).

[0109] In this way, the cracker 50 uses the heat and pressure of the combustion gas in the recompression stroke S4 to crack the hydrocarbon fuel supplied from the hydrocarbon fuel supply unit 30 (via the reforming port injector 25 and the reforming port 17) into carbon and hydrogen gas. This promotes the cracking reaction of the hydrocarbon fuel in the cracker 50. The cracker 50, which uses the heat and pressure in the recompression stroke S4 of the reciprocating engine 10, can generate the amount of hydrogen gas necessary to operate the reciprocating engine 10 even though it is small in size.

[0110] In the re-expansion stroke S5, the piston 12 descends. In the re-expansion stroke S5, the on-off valve 18 may be opened. When the on-off valve 18 is opened, the combustion gas from which carbon and hydrogen gas have been removed is introduced from the cracker 50 into the cylinder 11 via the reforming port 17. Opening the on-off valve 18 in the re-expansion stroke S5 is advantageous in reducing pumping losses in the reciprocating engine 10.

[0111] During the exhaust stroke S6, the combustion gas in the cylinder 11 is discharged through the exhaust port 15 as the piston 12 rises. During the exhaust stroke S6, the exhaust valve 16 opens. Note that during the exhaust stroke S6, the intake valve 14 and the on-off valve 18 are closed.

[0112] After the exhaust stroke S6, the reciprocating engine 10 returns to the intake stroke S1.

[0113] Instead of opening the on-off valve 18 in the re-expansion stroke S5, or in conjunction with opening the on-off valve 18 in the re-expansion stroke S5, the on-off valve 18 may be opened in the intake stroke S1. When the on-off valve 18 opens in the intake stroke S1, the combustion gas from which carbon and hydrogen gas have been removed is introduced from the cracker 50 into the cylinder 11 via the reforming port 17. This combustion gas becomes EGR gas.

[0114] If the on-off valve 18 is closed in the re-expansion stroke S5, the hydrocarbon fuel introduced into the cracker 50 in the re-compression stroke S4 will remain in the cracker 50 for a long time, which has the advantage of promoting the cracking reaction of the hydrocarbon fuel.

[0115] In this way, the fuel reforming system 1 including the reciprocating engine 10 that runs a six-stroke cycle stores the carbon produced by the decomposition of hydrocarbon fuel in the cracker 50. The reciprocating engine 10 burns the hydrogen gas produced by the decomposition of hydrocarbon fuel, so no carbon oxides are produced due to combustion. The fuel reforming system 1 can achieve carbon neutrality.

[0116] The fuel reforming system 1 utilizes the heat and pressure generated by the reciprocating engine 10, and therefore does not require a separate dedicated device to generate the heat and / or pressure required to decompose the hydrocarbon fuel. The fuel reforming system 1 is useful as an on-board system.

[0117] (carbon removal) As described above, the carbon decomposed from the hydrocarbon fuel in the recompression step S4 is stored in the cracker 50. Specifically, the carbon adheres to the catalyst 52 on the inner surface 51b of the support 51 in the cracker 50. FIG. 7 shows carbon adhered to the catalyst 52 on the inner surface 51b of the support 51 in the cracker 50.

[0118] As the amount of carbon stored in the decomposer 50 increases, the carbon begins to extend in a rod-like shape as carbon nanotubes 100 from the catalyst 52 on the inner surface 51b of the support 51. New carbon continues to adhere and accumulate at the connection point K between the base end 100a of the existing rod-like carbon nanotube 100 and the catalyst 52 on the inner surface 51b of the support 51, causing the carbon nanotube 100 to continue to extend. Because the carbon nanotube 100 itself is both hard and soft, the bond between the carbon nanotube 100 and the catalyst 52 must be released in order to recover the carbon nanotube 100.

[0119] As described above, the vibrator 56 of the carbon removal mechanism 55 applies vibrations to the catalyst 52 on the inner surface 51b of the support 51 via the cylindrical portion 54a of the case 54 and the support 51. The vibrations are transmitted from the vibrator 56 of the carbon removal mechanism 55 to the catalyst 52 on the inner surface 51b of the support 51 via the cylindrical portion 54a of the case 54 and the support 51. In other words, the vibrator 56 of the carbon removal mechanism 55 applies vibrations to the catalyst 52 without coming into direct contact with it.

[0120] As a result, the carbon nanotube 100 is broken at a connection point K between the base end 100a of the carbon nanotube 100 and the catalyst 52 on the inner surface 51b of the support 51. The carbon nanotube 100 is then removed from the catalyst 52 on the inner surface 51b of the support 51. That is, the oscillator 56 of the carbon removal mechanism 55 removes the carbon nanotube 100 from the catalyst 52 without directly contacting the catalyst 52. Because the oscillator 56 of the carbon removal mechanism 55 does not directly contact the catalyst 52, carbon can be removed from the catalyst 52 without peeling the catalyst 52 from the support 51.

[0121] (Normal operation mode, carbon removal mode, and carbon discharge mode) 8 shows the carbon recovery unit 70 in a normal operation mode M1, a carbon removal mode M2, and a carbon discharge mode M3. The fuel reforming system 1 executes the normal operation mode M1, the carbon removal mode M2, and the carbon discharge mode M3. The modes M1 to M3 are switched by a controller 81 in response to a command from a user, for example.

[0122] In the normal operation mode M1, the above-described six-stroke cycle is executed. In the normal operation mode M1, the exhaust valve 73 always closes the exhaust passage 72 in all strokes S1 to S6. In the normal operation mode M1, the on-off valve 18 opens in the recompression stroke S4, and the reforming port injector 25 injects hydrocarbon fuel into the reforming port 17. In the normal operation mode M1, the hydrogen injector 26 (hydrogen gas supply unit 40) injects (supplies) hydrogen gas into the cylinder 11 in the intake stroke S1 and / or the compression stroke S2.

[0123] In the normal operation mode M1, in the recompression step S4, hydrocarbon fuel is supplied from the hydrocarbon fuel supply unit 30 to the cracker 50 via the reforming port injector 25 and the reforming port 17, and combustion gas is supplied from inside the cylinder 11 to the cracker 50 via the reforming port 17. In the normal operation mode M1, carbon decomposed from the hydrocarbon fuel in the recompression step S4 is stored in the cracker 50. In the normal operation mode M1, the oscillator 56 of the carbon removal mechanism 55 does not vibrate in any of the steps S1 to S6.

[0124] In the carbon removal mode M2, the above-described six-stroke cycle is not executed. In the carbon removal mode M2, the reciprocating engine 10 may be stopped. In the carbon removal mode M2, the exhaust valve 73 closes the exhaust passage 72. In the carbon removal mode M2, the on-off valve 18 closes and the reforming port injector 25 does not inject hydrocarbon fuel into the reforming port 17. In the carbon removal mode M2, hydrocarbon fuel and combustion gas are not introduced into the cracker 50. In the carbon removal mode M2, the oscillator 56 of the carbon removal mechanism 55 oscillates. In the carbon removal mode M2, carbon is removed from the catalyst 52 by the oscillation of the oscillator 56 of the carbon removal mechanism 55.

[0125] In the carbon discharge mode M3, the above-described six-stroke cycle is executed. In the carbon discharge mode M3, the discharge valve 73 opens the discharge path 72. In the carbon discharge mode M3, the on-off valve 18 opens in the recompression stroke S4. In the carbon discharge mode M3, the combustion gas is introduced from the cylinder 11 into the cracker 50 via the reforming port 17 in the recompression stroke S4. In the carbon discharge mode M3, the combustion gas introduced into the cracker 50 in the recompression stroke S4 pushes the carbon removed from the catalyst 52 into the discharge path 72. In this way, in the carbon discharge mode M3, the combustion gas is used to discharge carbon into the discharge path in the recompression stroke S4.

[0126] The carbon discharged into the discharge path 72 of the carbon recovery unit 70 is removed from the vehicle, for example, when the vehicle is brought in for maintenance. In this way, the carbon recovery unit 70 recovers the carbon produced in the decomposer 50. In particular, the carbon recovery unit 70 recovers the carbon removed from the catalyst 52 of the decomposer 50. The recovered carbon can be reused as a recycled product.

[0127] In the carbon discharge mode M3, the hydrogen injector 26 (hydrogen gas supply unit 40) does not have to inject (supply) hydrogen gas into the cylinder 11 during the intake stroke S1 and / or the compression stroke S2. In the carbon discharge mode M3, the first switching valve 44 and the second switching valve 45 in the hydrogen gas supply unit 40 may be closed.

[0128] (Action and effect) The reciprocating engine 10 includes a compression stroke S2 ​​and an expansion stroke S3, followed by a recompression stroke S4 in which the combustion gas is compressed by the upward movement of the piston 12. The hydrocarbon fuel supply unit 30 supplies hydrocarbon fuel to the cracker 50.

[0129] The cracker 50 uses the heat and pressure of the combustion gas in the recompression step S4 to decompose the hydrocarbon fuel into carbon and hydrogen gas. The cracker 50 can efficiently decompose the hydrocarbon fuel. The carbon is stored in the cracker 50.

[0130] The hydrogen gas supply unit 40 supplies the hydrogen gas produced in the cracker 50 as fuel into the cylinders 11 of the reciprocating engine 10. The reciprocating engine 10 operates by combusting the hydrogen gas. No carbon oxides are produced by combustion. The reciprocating engine 10 can supply heat and pressure to the cracker 50 for cracking hydrocarbon fuel while outputting driving force to run the vehicle.

[0131] The fuel reforming system 1 can achieve carbon neutrality. Because the fuel reforming system 1 utilizes the heat and pressure generated by the reciprocating engine 10, a separate dedicated device is not required to generate the heat and / or pressure required to decompose the hydrocarbon fuel. The fuel reforming system 1 is useful as an on-board system installed in a vehicle.

[0132] Furthermore, the decomposer 50 has a catalyst 52 to which carbon adheres, and a carbon removal mechanism 55 that removes carbon from the catalyst 52 without directly contacting the catalyst 52. Because the carbon removal mechanism 55 does not directly contact the catalyst 52, it can remove carbon from the catalyst 52 without peeling the catalyst 52 from the support 51. Then, a carbon recovery unit 70 recovers the carbon removed from the catalyst 52.

[0133] As described above, in the fuel reforming system 1 mounted on a vehicle, carbon can be collected without peeling the catalyst 52 from the support 51.

[0134] This is advantageous in that it is not necessary to apply physical impact to the catalyst 52 by sandblasting or the like, and the catalyst 52 is not peeled off from the support 51.

[0135] The vibrator 56 of the carbon removal mechanism 55 applies vibration to the catalyst 52 without directly contacting it, so that carbon can be removed from the catalyst 52 without peeling the catalyst 52 off the support 51.

[0136] By arranging the vibrator 56 on the opposite side of the catalyst 52 with (the cylindrical portion 54a of the case 54 and) the support body 51 interposed therebetween, the vibrator 56 can be prevented from coming into direct contact with the catalyst 52.

[0137] The catalyst 52 is supported on the inner surface 51b of the cylindrical support 51 and the vibrator 56 is held on the outer surface 51a side of the cylindrical support 51 (sandwiched between the cylindrical portion 54a of the case 54), thereby making it possible to prevent the vibrator 56 from coming into direct contact with the catalyst 52 with a simple configuration.

[0138] The carbon recovery section 70 has a discharge passage 72 and a discharge valve 73, which allow the carbon to be easily recovered.

[0139] The carbon removal from the catalyst 52 by the carbon removal mechanism 55 in the carbon removal mode M2 ​​and the carbon discharge by the carbon recovery unit 70 using the combustion gas in the carbon discharge mode M3 can be suitably used.

[0140] Second Embodiment A fuel reforming system 1 for a vehicle according to a second embodiment will be described. In the following description, the same components as those in the above embodiment will be given the same reference numerals, and detailed description thereof may be omitted. FIG. 9 shows an inner surface 51b of a support 51 in a decomposer 50 according to the second embodiment. In the following description, the upstream side (the catechin pump 58 side) in the flow of a liquid L described below will be simply referred to as the upstream side, and the downstream side (the inner surface 51b side of the support 51) in the flow of the liquid L will be simply referred to as the downstream side.

[0141] The cracker 50 includes a support 51, a catalyst 52, a hydrogen separation membrane 53, a case 54, a carbon removal mechanism 55, and a water separation membrane 57 as a liquid separation membrane. The support 51 is formed in a cylindrical shape. The cylindrical support 51 supports the catalyst 52 on an inner surface 51b. Specifically, the catalyst 52 is applied to a portion of the inner surface 51b of the cylindrical support 51.

[0142] The water separation membrane 57 is provided on a part of the inner surface 51b of the cylindrical support 51 so as to be adjacent to the catalyst 52. On the inner surface 51b of the support 51, the catalyst 52 and the water separation membrane 57 are arranged alternately so as to be adjacent to each other. Zeolite, for example, is used as the water separation membrane 57. The water separation membrane 57 may be a separation membrane other than zeolite.

[0143] The carbon removal mechanism 55 includes a catechin pump 58 as a catechin supply device, a catechin passage 59, and a catechin valve 60. The catechin pump 58 is disposed outside the case 54. The catechin pump 58 pumps the liquid L. The catechin pump 58 is connected to a liquid tank (not shown). The liquid tank stores the liquid L.

[0144] The catechin passage 59 includes a main passage 59a and multiple branch passages 59b. The upstream end of the main passage 59a of the catechin passage 59 is connected to the catechin pump 58. The multiple branch passages 59b of the catechin passage 59 penetrate the cylindrical portion 54a of the case 54 and the cylindrical support 51. The multiple branch passages 59b are arranged at intervals from one another. In the catechin passage 59, the upstream ends of the branch passages 59b are connected to the main passage 59a. The downstream ends of the branch passages 59b of the catechin passage 59 are connected to (communicate with) the water separation membrane 57 on the inner surface 51b of the support 51.

[0145] The catechin valve 60 is connected to the main passage 59a of the catechin passage 59. The catechin valve 60 opens and closes the catechin passage 59.

[0146] As shown by the two-dot chain line in FIG. 5 , the catechin pump 58 is electrically connected to the controller 81. The controller 81 outputs a control signal to the catechin pump 58. The catechin pump 58 switches the pumping of the liquid L between ON and OFF based on the control signal from the controller 81. The catechin valve 60 is electrically connected to the controller 81. The controller 81 outputs a control signal to the catechin valve 60. The catechin valve 60 switches the catechin passage 59 between open and closed states based on the control signal from the controller 81.

[0147] The catechin pump 58 supplies the liquid L to the catalyst 52 through the main path 59a and the branch path 59b of the catechin passage 59 and the water separation membrane 57. The catechin pump 58 pressurizes the water separation membrane 57. The pressurization is performed, for example, up to about several atmospheres.

[0148] The liquid L is pumped by the catechin pump 58, passes through the main path 59a and the branch path 59b of the catechin passage 59, and is supplied to the water separation membrane 57 on the inner surface 51b of the support 51. When pressure is applied to the water separation membrane 57 (by the catechin pump 58) while the liquid L is supplied to the water separation membrane 57, the liquid L in the water separation membrane 57 seeps out to the catalyst 52 adjacent to the water separation membrane 57 and is supplied to the catalyst 52.

[0149] The liquid L contains water and catechin. Catechin is a type of polyphenol and is a main component of green tea. Examples of catechin include epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate.

[0150] Catechin has the effect of loosening the bonds of the carbon nanotubes 100. Water alone cannot loosen the bonds of the carbon nanotubes 100. Catechin, which has an affinity for both the carbon nanotubes 100 and water, can make the carbon nanotubes 100 and water blend with each other. By supplying liquid L (containing water and catechin) from the water separation membrane 57 to the adjacent catalyst 52, the carbon nanotubes 100 can be removed from the catalyst 52 at the connection point K between the base end 100a of the carbon nanotube 100 and the catalyst 52 on the inner surface 51b of the support 51.

[0151] The catechin pump 58 is not in direct contact with the catalyst 52. The catechin pump 58 supplies the liquid L (containing catechin) to the catalyst 52 through a catechin passage 59 and a water separation membrane 57. The catechin pump 58 of the carbon removal mechanism 55 removes carbon from the catalyst 52 without coming into direct contact with the catalyst 52.

[0152] In the normal operation mode M1, the catechin pump 58 is stopped and / or the catechin valve 60 is closed. In the carbon removal mode M2, the discharge valve 73 closes the discharge path 72. In the carbon removal mode M2, the catechin pump 58 is started and the catechin valve 60 is opened. In the carbon removal mode M2, the catechin pump 58 of the carbon removal mechanism 55 supplies the liquid L (containing catechin) to the catalyst 52 through the water separation membrane 57, thereby removing carbon from the catalyst 52.

[0153] In the carbon discharge mode M3, the discharge valve 73 opens the discharge path 72. In the carbon discharge mode M3, the on-off valve 18 opens, and the combustion gas is introduced from inside the cylinder 11 into the cracker 50 via the reforming port 17. In the carbon discharge mode M3, the combustion gas is used to discharge carbon into the discharge path.

[0154] The other configurations are the same as those in the first embodiment.

[0155] According to this embodiment, the catechin pump 58 of the carbon removal mechanism 55 supplies the liquid L containing catechin to the catalyst 52, so that carbon can be removed from the catalyst 52 by the action of the catechin without coming into direct contact with the catalyst 52.

[0156] Furthermore, by passing the liquid L containing catechins through the water separation membrane 57 adjacent to the catalyst 52, it becomes easier to supply the liquid L containing catechins to the catalyst 52.

[0157] Third Embodiment A fuel reforming system 1 for a vehicle according to the third embodiment will be described. In the following description, the same components as those in the above-described embodiment will be assigned the same reference numerals, and detailed description thereof may be omitted. Figure 10 shows each step of a modified four-stroke cycle according to the third embodiment.

[0158] The reciprocating engine 10 executes a modified four-stroke cycle that includes a compression stroke T1 in which the air-fuel mixture containing hydrogen gas in the cylinder 11 is compressed by the rising piston 12, an expansion stroke T2 in which the piston 12 descends as the air-fuel mixture is burned, a recompression stroke T3 in which the rising piston 12 compresses the combustion gas, and a scavenging stroke T4 in which the piston 12 descends to discharge exhaust gas from the cylinder 11 through the exhaust port 15 and introduce intake air into the cylinder 11 through the intake port 13.

[0159] The other configurations are the same as those of the first and second embodiments.

[0160] <Other embodiments> Although the present disclosure has been described above with reference to preferred embodiments, such description is not limiting, and it goes without saying that various modifications, substitutions, or combinations are possible.

[0161] The vibrator 56 of the carbon removal mechanism 55 may apply vibration to the catalyst 52 through an air layer without directly contacting the catalyst 52. The vibrator 56 may be fixed directly to the support 51 without sandwiching the case 54. The vibrator 56 may be held on the support 51 via a bracket or the like.

[0162] The carrier may be, for example, plate-shaped. In this case, it is preferable that a hydrogen separation membrane is inserted between the inner surfaces of two plate-shaped carriers and that a catalyst is supported on the inner surfaces of the plate-shaped carriers.

[0163] The cracker may have a cylindrical reaction vessel, a plurality of ball-shaped supports packed in the reaction vessel, a catalyst supported on the surfaces (outer surfaces) of the ball-shaped supports, a hydrogen separation membrane provided in the reaction vessel, and a case for accommodating the reaction vessel. In this case, gaps are formed between the surfaces (outer surfaces) of the plurality of ball-shaped supports. The carbon removal mechanism removes carbon from the catalyst supported on the ball-shaped supports without directly contacting the catalyst.

[0164] The cracker 50 may have any structure that can utilize the heat and pressure of the combustion gases to crack the hydrocarbon fuel.

[0165] The reciprocating engine 10 may execute a cycle other than the six-stroke cycle and the modified four-stroke cycle, as long as the cycle includes at least a compression stroke, an expansion stroke, and a recompression stroke.

[0166] The reciprocating engine 10 may be a compression ignition engine. [Explanation of symbols]

[0167] S1 Intake stroke S2 compression stroke S3 Expansion stroke S4 Recompression process S5 Re-expansion stroke S6 exhaust stroke T1 compression stroke T2 Expansion stroke T3 Recompression process T4 Scavenging stroke M1 Normal operation mode M2 Carbon removal mode M3 Carbon Emission Mode A void L liquid 1 Fuel reforming system 10 Reciprocating Engine 11 cylinders 12 pistons 17 Reformer port 18 On-off valve 25 Modified port injector 26 Hydrogen injector 30 Hydrocarbon fuel supply unit 40 Hydrogen gas supply unit 50 Decomposer 51 Support 51a Exterior 51b Inner surface 52 Catalyst 53 Hydrogen separation membrane 53a Exterior 53b Inside 54 cases 55 Carbon removal mechanism 56 vibrator 57 Water separation membrane (liquid separation membrane) 58 Catechin pump (catechin supply device) 59 Catechin Passage 60 Catechin valve 70 Carbon Recovery Section 71 Housing 72 Exhaust channel 73 Discharge valve 74 Discharge hole

Claims

1. a reciprocating engine mounted on a vehicle and having pistons reciprocating within cylinders; a cracker for cracking a hydrocarbon fuel into carbon and hydrogen gas and storing the carbon; a hydrocarbon fuel supply unit that supplies the hydrocarbon fuel to the cracker; a hydrogen gas supply unit that supplies the hydrogen gas generated by the decomposer into the cylinder; a carbon recovery unit that recovers the carbon generated in the decomposer, the reciprocating engine executes a cycle including at least a compression stroke in which the air-fuel mixture containing the hydrogen gas in the cylinder is compressed by the rising of the piston, an expansion stroke in which the piston is lowered by combustion of the air-fuel mixture, and a recompression stroke in which the combustion gas is compressed by the rising of the piston, the cracker utilizes the heat and pressure of the combustion gas in the recompression stroke to crack the hydrocarbon fuel supplied from the hydrocarbon fuel supply unit into the carbon and the hydrogen gas, The decomposer comprises: a catalyst to which the carbon adheres; a carbon removal mechanism that removes the carbon from the catalyst without directly contacting the catalyst, The carbon recovery unit recovers the carbon removed from the catalyst.

2. 2. The fuel reforming system for a vehicle according to claim 1, wherein the carbon removal mechanism includes a vibrator that applies vibration to the catalyst without directly contacting the catalyst.

3. the cracker has a support that supports the catalyst, the oscillator is disposed on the opposite side of the catalyst with the support therebetween, 3. The fuel reforming system for a vehicle according to claim 2, wherein the vibrator applies vibration to the catalyst via the support.

4. the support is cylindrical and supports the catalyst on its inner surface; 4. The fuel reforming system for a vehicle according to claim 3, wherein the vibrator is held on an outer surface side of the support.

5. 5. The fuel reforming system for a vehicle according to claim 1, wherein the carbon removal mechanism includes a catechin supply device that supplies a liquid containing catechin to the catalyst.

6. The decomposer comprises: a support that supports the catalyst; a liquid separation membrane provided on the support so as to be adjacent to the catalyst; The fuel reforming system for a vehicle according to claim 5 , wherein the catechin supplying device supplies the liquid to the catalyst through the liquid separation membrane.

7. The carbon recovery unit includes: an exhaust passage through which the carbon removed from the catalyst is discharged; 5. The fuel reforming system for a vehicle according to claim 1, further comprising: a discharge valve for opening and closing the discharge passage.

8. a carbon removal mode in which the exhaust valve closes the exhaust passage and the carbon is removed from the catalyst by the carbon removal mechanism; a carbon discharge mode in which the discharge valve opens the discharge passage and the carbon is discharged into the discharge passage by utilizing the combustion gas.

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