JP2024078664A - Fuel tank and vehicle equipped with same - Google Patents

Abstract

A technology is provided that can suitably discharge liquid ammonia from a fuel tank without requiring a fuel pump for discharging the liquid ammonia from the fuel tank.
[Solution] A fuel tank for an internal combustion engine that uses hydrogen gas or liquid ammonia as fuel, wherein the hydrogen gas and the liquid ammonia are stored within the fuel tank, and the fuel tank is provided with a first outlet which is an outlet for the hydrogen gas, and a second outlet which is an outlet for the liquid ammonia.
[Selected Figure] Figure 1

Description

The technology disclosed in this specification relates to a fuel tank and a vehicle equipped with the same.

Patent Document 1 discloses an engine that uses liquid ammonia as fuel. In this document, liquid ammonia stored in a fuel tank is supplied to a cylinder and burned to generate combustion gas, which is then used to power the engine.

JP 2015-135067 A

Fuel tanks used in such engines are generally provided with a fuel pump for pressurizing the liquid ammonia stored inside and discharging it to the outside. This specification provides a technology that allows liquid ammonia to be suitably discharged from the fuel tank without the need for a fuel pump for discharging the liquid ammonia.

As a first aspect, this specification discloses a fuel tank for an internal combustion engine that uses hydrogen gas or liquid ammonia as fuel. The hydrogen gas and the liquid ammonia are stored in the fuel tank, and the fuel tank is provided with a first outlet for the hydrogen gas and a second outlet for the liquid ammonia.

In the above fuel tank, hydrogen gas and liquid ammonia are both stored inside the fuel tank. Because the hydrogen gas in the fuel tank is at high pressure, the pressure of the hydrogen gas acts on the liquid ammonia. Therefore, when liquid ammonia is discharged from the second outlet, the liquid ammonia is discharged from the fuel tank at high pressure due to the pressure of the hydrogen gas. Therefore, in the above fuel tank, high-pressure liquid ammonia can be discharged without requiring a fuel pump for pressurizing and discharging the liquid ammonia. In addition, in this fuel tank, hydrogen gas can be discharged from the first outlet. Therefore, the hydrogen gas stored in the fuel tank can be directly used as fuel.

In a second aspect, the ratio of the hydrogen gas and the liquid ammonia stored in the fuel tank in the first aspect may be changeable according to the outside air temperature. In areas or seasons where the outside air temperature is low, the combustion efficiency of liquid ammonia decreases. For this reason, for example, in areas where the outside air temperature is low, the ratio of hydrogen gas stored in the fuel tank can be increased and the hydrogen gas can be used as fuel to improve the combustion efficiency.

As a third aspect, the present specification discloses a vehicle including an internal combustion engine fueled by hydrogen gas or liquid ammonia, and a fuel tank for storing the hydrogen gas and the liquid ammonia. The fuel tank includes a first outlet for the hydrogen gas and a second outlet for the liquid ammonia. The first outlet and the second outlet are connected to the internal combustion engine.

The vehicle has a fuel tank in which both hydrogen gas and liquid ammonia are stored. Because the hydrogen gas in the fuel tank is at high pressure, the hydrogen gas pressure acts on the liquid ammonia. Therefore, when liquid ammonia is discharged from the second discharge port, the liquid ammonia is discharged from the fuel tank at high pressure due to the pressure of the hydrogen gas. Therefore, the vehicle can supply high-pressure liquid ammonia to the internal combustion engine without requiring a fuel pump to pressurize and discharge the liquid ammonia. Furthermore, in this fuel tank, hydrogen gas can be discharged from the first discharge port. Therefore, the vehicle can run by directly using the hydrogen gas stored in the fuel tank as fuel.

In a fourth aspect, in the third aspect, when the fuel tank is mounted on the vehicle, the first outlet of the fuel tank may be located above the second outlet. Hydrogen gas has a smaller specific gravity than liquid ammonia. Therefore, when the fuel tank is mounted on the vehicle, by positioning the first outlet from which hydrogen gas is discharged above the second outlet from which liquid ammonia is discharged, hydrogen gas and liquid ammonia can be stably supplied to the internal combustion engine.

In a fifth aspect, in the third or fourth aspect, the fuel tank may be configured to be detachable from the vehicle. In such a configuration, for example, the fuel tank can be removed (i.e., only the fuel tank can be carried) and hydrogen gas or liquid ammonia can be filled into the fuel tank. Even if there is no means of refilling the fuel, the user can replace the fuel tank with a spare fuel tank and continue to run the vehicle, thereby improving user convenience.

1 is a schematic diagram showing the configuration of a fuel tank and an internal combustion engine according to an embodiment;

The fuel tank 2 of the embodiment will be described below with reference to the drawings. The fuel tank 2 is mounted, for example, on a vehicle 10 together with an internal combustion engine 3. As shown in FIG. 1, hydrogen gas 4 and liquid ammonia 5 are both stored inside the fuel tank 2. The fuel tank 2 shown in FIG. 1 corresponds to the posture when it is actually mounted on the vehicle 10 and used. That is, the up-down direction of the fuel tank 2 in FIG. 1 corresponds to the vertical direction. The hydrogen gas 4 has a smaller specific gravity than the liquid ammonia 5. Therefore, as shown in FIG. 1, the liquid ammonia 5 occupies the space below the fuel tank 2, and the hydrogen gas 4 occupies the space above the fuel tank 2.

The fuel tank 2 has a first outlet 8 and a second outlet 9. The first outlet 8 is provided on the upper surface 2a of the fuel tank 2. The second outlet 9 is provided on the lower part of the side surface 2b of the fuel tank 2. Of the internal space of the fuel tank 2, the space in the range adjacent to the first outlet 8 is filled with hydrogen gas 4, and the space in the range adjacent to the second outlet 9 is filled with liquid ammonia 5. That is, the fuel tank 2 is configured so that the hydrogen gas 4 is discharged to the outside from the first outlet 8, and the liquid ammonia 5 is discharged to the outside from the second outlet 9. The positions of the first outlet 8 and the second outlet 9 may be appropriately adjusted according to the ratio (volume) of the hydrogen gas 4 and the liquid ammonia 5 stored inside the fuel tank 2.

The fuel tank 2 is also configured to be detachable from the vehicle 10. Therefore, for example, with the fuel tank 2 removed, the inside of the fuel tank 2 can be filled with hydrogen gas 4 or liquid ammonia 5, or the fuel tank 2 can be replaced with a spare fuel tank 2.

The internal combustion engine 3 includes a cylinder 11 having a combustion chamber 11a therein, a hydrogen gas supply device 12 that supplies hydrogen gas 4 into the combustion chamber 11a, an ammonia supply device 13 that supplies liquid ammonia 5 into the combustion chamber 11a, an intake device 14 that supplies air into the combustion chamber 11a, an ignition device 15 that generates sparks in the combustion chamber 11a, and an exhaust device 16 that exhausts exhaust gas from the combustion chamber 11a after combustion.

The cylinder 11 has a cylindrical cylinder liner 11b, a cylinder head 11c that covers the upper opening of the cylinder liner 11b, a piston 11d that is reciprocally disposed within the cylinder liner 11b, and a crank 11e that is connected to the piston 11d. The space surrounded by the cylinder liner 11b, the cylinder head 11c, and the piston 11d is the combustion chamber 11a. Therefore, the combustion chamber 11a is compressed to a high pressure state by the piston 11d moving upward in the figure. In addition, the driving force that rotates the crank 11e is transmitted by burning hydrogen gas 4 or liquid ammonia 5 in this combustion chamber 11a and reciprocating the piston 11d.

The intake system 14 includes an intake pipe 14a, one end of which is fixed to the cylinder head 11c, and an intake valve 14b provided in the intake pipe 14a. The intake valve 14b is configured to be opened and closed by a drive means (not shown). By opening the intake valve 14b, the intake pipe 14a communicates with the combustion chamber 11a, and air is supplied from the intake pipe 14a to the combustion chamber 11a.

The exhaust system 16 includes an exhaust pipe 16a, one end of which is fixed to the cylinder head 11c, and an exhaust valve 16b provided in the exhaust pipe 16a. The exhaust valve 16b is configured to be opened and closed by a drive means (not shown). By opening the exhaust valve 16b, the exhaust valve 16b communicates with the combustion chamber 11a, and the exhaust gas after combustion in the combustion chamber 11a is discharged from the exhaust valve 16b.

The ignition device 15 is, for example, an ignition plug, and is fixed in the approximate center of the cylinder head 11c with its tip positioned within the combustion chamber 11a. The tip of the ignition device 15 is provided with an ignition part 15a that generates a spark in the upper center of the combustion chamber 11a.

The hydrogen gas supply device 12 is, for example, an injector, and is connected to the first discharge port 8 of the fuel tank 2. The hydrogen gas supply device 12 is fixed to the cylinder head 11c with its tip disposed within the combustion chamber 11a. The tip of the hydrogen gas supply device 12 is provided with an injection section 12a that injects hydrogen gas 4 into the combustion chamber 11a. The hydrogen gas supply device 12 is fixed to the cylinder head 11c with the injection section 12a disposed within the combustion chamber 11a. Alternatively or in addition to this, the injection section 12a may be fixed to the intake pipe 14a with the injection section 12a disposed within the intake pipe 14a.

The ammonia supply device 13 is, for example, an injector, and is connected to the second discharge port 9 of the fuel tank 2. The ammonia supply device 13 is fixed to the cylinder head 11c with its tip disposed in the combustion chamber 11a. The tip of the ammonia supply device 13 is provided with an injection unit 13a that injects liquid ammonia 5 into the combustion chamber 11a. The ammonia supply device 13 is fixed to the cylinder head 11c with the injection unit 13a disposed in the combustion chamber 11a. Alternatively, or in addition, the ammonia supply device 13 may be fixed to the intake pipe 14a with the injection unit 13a disposed in the intake pipe 14a.

In the internal combustion engine 3 configured as described above, the hydrogen gas 4 injected from the injection unit 12a or the liquid ammonia 5 injected from the injection unit 13a is burned together with air in the combustion chamber 11a by a spark generated by the ignition unit 15a, thereby causing the crank 11e to rotate.

As described above, the fuel tank 2 of this embodiment stores both hydrogen gas 4 and liquid ammonia 5 inside. Since the hydrogen gas 4 in the fuel tank 2 is at high pressure, the pressure of the hydrogen gas 4 acts on the liquid ammonia 5. Therefore, when the liquid ammonia 5 is discharged from the second discharge port 9, the liquid ammonia 5 is discharged from the fuel tank 2 at high pressure due to the pressure of the hydrogen gas 4. Therefore, the fuel tank 2 of this embodiment can discharge high-pressure liquid ammonia 5 without requiring a fuel pump for pressurizing and discharging the liquid ammonia 5. In addition, the fuel tank 2 can discharge the hydrogen gas 4 from the first discharge port 8. Therefore, the hydrogen gas 4 stored in the fuel tank 2 can be directly used as fuel.

In addition, in this embodiment, when the fuel tank 2 is mounted on the vehicle 10, a first outlet 8, which is an outlet for hydrogen gas 4, is provided on the upper surface 2a of the fuel tank 2, and a second outlet 9, which is an outlet for liquid ammonia 5, is provided on the side surface 2b of the fuel tank 2. Hydrogen gas 4 has a smaller specific gravity than liquid ammonia 5. Therefore, when the fuel tank 2 is mounted on the vehicle 10, the first outlet 8 from which hydrogen gas 4 is discharged is positioned above the second outlet 9 from which liquid ammonia 5 is discharged, thereby enabling the hydrogen gas 4 and liquid ammonia 5 to be stably supplied to the internal combustion engine 3.

In addition, in this embodiment, the fuel tank 2 is configured to be detachable from the vehicle 10. Therefore, when the fuel (hydrogen gas 4 or liquid ammonia 5) in the fuel tank 2 runs out, the vehicle 10 can continue to run by carrying only the fuel tank 2 and refilling it with fuel, or by replacing the fuel tank 2 with a spare fuel tank 2 (i.e., one in which fuel is stored), which provides high convenience to the user.

Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples given above. Below, we list some variations of the above-mentioned embodiments.

The above-described embodiment may further include a reformer that vaporizes and reforms the liquid ammonia 5. By reforming the liquid ammonia 5, a combustion gas containing hydrogen can be generated. Therefore, the combustion gas generated by such a reformer may be used as fuel.

In addition, for example, only hydrogen may be extracted from the combustion gas generated by the reformer and supplied to the fuel tank 2. By configuring in this manner, the ratio of hydrogen gas 4 and liquid ammonia 5 stored in the fuel tank 2 may be changed. This makes it possible to adjust the pressure of the hydrogen gas 4 in the fuel tank 2.

The ratio of hydrogen gas 4 to liquid ammonia 5 stored in the fuel tank 2 may be adjusted depending on the outside temperature and season of the region in which the fuel tank 2 is sold. For example, in regions and seasons where the outside temperature is low, the combustion efficiency of liquid ammonia 5 decreases. For this reason, for example, in regions where the outside temperature is low, by increasing the ratio of hydrogen gas 4 stored in the fuel tank 2, the easily combustible hydrogen gas 4 can be mainly used as fuel, improving combustion efficiency.

The technical elements described in this specification or drawings have technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of those objectives is itself technically useful.

2: fuel tank, 2a: top surface, 2b: side surface, 3: internal combustion engine, 4: hydrogen gas, 5: liquid ammonia, 8: first outlet, 9: second outlet, 10: vehicle, 11: cylinder, 12: hydrogen gas supply device, 13: ammonia supply device, 14: intake device, 15: ignition device, 16: exhaust device

Claims (5)

1. A fuel tank for an internal combustion engine fueled by hydrogen gas or liquid ammonia, comprising:
the hydrogen gas and the liquid ammonia are stored in the fuel tank,
a first outlet which is an outlet for the hydrogen gas;
a second outlet which is an outlet for the liquid ammonia;
A fuel tank comprising: 2. The fuel tank according to claim 1,
A fuel tank, wherein a ratio of the hydrogen gas and the liquid ammonia stored in the fuel tank is changeable according to an outside air temperature. A vehicle comprising an internal combustion engine fueled by hydrogen gas or liquid ammonia, and a fuel tank for storing the hydrogen gas and the liquid ammonia,
the fuel tank includes a first outlet which is an outlet for the hydrogen gas and a second outlet which is an outlet for the liquid ammonia,
The first outlet and the second outlet are connected to the internal combustion engine. 4. A vehicle according to claim 3,
When the fuel tank is mounted on the vehicle, the first discharge port of the fuel tank is located higher than the second discharge port. A vehicle according to claim 3 or 4,
The fuel tank is configured to be detachable from the vehicle.

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