Hydrofoil propulsion system and hydrofoil

Abstract

To continue fuel supply to an engine even during a blackout without providing an emergency fuel tank for blackout.SOLUTION: A propulsion system 7 of a hydrofoil vessel 100 includes: a fuel tank 74; an engine 72 driven by fuel in the fuel tank 74 for propelling a hull 2 of the hydrofoil vessel 100; a first pump 77 driven by the engine 72; a second flow path 73b with its both ends connected to the first pump 77 in which fuel is circulated by the first pump 77; a flow amount control valve 78 for distributing a part of the fuel in the second flow path 73b to the engine 72; and an ejector 79 provided in the second flow path 73b, having the fuel in the second flow path 73b circulating through as driving fluid, as well as having a suction opening 79c communicated with a fuel tank 74 through a first flow path 73a.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The technology of this disclosure relates to hydrofoil vessels and their propulsion systems. [Background technology]

[0002] For example, a propulsion system for a ship equipped with a propulsion engine is known, as disclosed in Patent Document 1. This propulsion system has a main pump that pressurizes fuel in a fuel tank and supplies it to the engine, and a backup pump that takes over in the event of a breakdown or other problem with the main pump. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-68846 Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of a general ship such as the one described above, an emergency fuel tank may be installed higher than the engine so that fuel can continue to be supplied to the engine even if the pump becomes inoperable due to a power outage. In other words, when the pump becomes inoperable, fuel from the emergency fuel tank is supplied to the engine by its own weight, allowing for continuous fuel supply. However, in the case of a hydrofoil vessel, which is smaller than a general ship, it is not easy to secure the installation space for such an emergency fuel tank, and therefore it is difficult to continue to supply fuel to the engine during a power outage, etc.

[0005] The technology disclosed herein has been made in consideration of these points, and its purpose is to continue supplying fuel to the engine even during a power outage without providing an emergency fuel tank for use in the event of a power outage. [Means for solving the problem]

[0006] The propulsion system for a hydrofoil vessel disclosed herein includes a fuel tank, an engine, a first pump, a second flow path, a distribution mechanism, and an ejector. The engine is driven by fuel in the fuel tank and propels the hull of the hydrofoil vessel. The first pump is driven by the engine. Both ends of the second flow path are connected to the first pump, and fuel is circulated by the first pump. The distribution mechanism distributes a portion of the fuel in the second flow path to the engine. The ejector is provided in the second flow path, and the fuel in the second flow path flows through the ejector as a driving fluid, and an inlet of the ejector is connected to the fuel tank via the first flow path.

[0007] The hydrofoil vessel of the present disclosure also includes a hull and the aforementioned propulsion system mounted on the hull. [Effects of the Invention]

[0008] According to the hydrofoil ship propulsion system of the present disclosure, fuel can be continuously supplied to the engine even during a power outage without providing an emergency fuel tank for use in the event of a power outage.

[0009] According to the hydrofoil vessel of the present disclosure, fuel can be continuously supplied to the engine even during a power outage without providing an emergency fuel tank for use in the event of a power outage. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of the hydrofoil vessel as seen from the front right. [Figure 2] FIG. 2 is a perspective view of the hydrofoil vessel as seen from the rear left. [Figure 3] FIG. 3 is a side view of the hydrofoil vessel seen from the right side. [Figure 4] FIG. 4 is a perspective view of the front and rear struts and foils of a hydrofoil vessel. [Figure 5] FIG. 5 is a schematic diagram showing the configuration of the propulsion system in the first operating mode. [Figure 6] FIG. 6 is a schematic diagram showing the configuration of the propulsion system in the second operating mode. [Figure 7] FIG. 7 is a schematic configuration diagram showing a propulsion system according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Exemplary embodiments will now be described in detail with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a hydrofoil vessel 100 as seen from the right front; and Figure 2 is a perspective view of the hydrofoil vessel 100 as seen from the left rear.

[0012] As shown in Figures 1 and 2, the hydrofoil vessel 100 comprises a hull 2, a front foil 4 attached to the hull 2 ​​via a front strut 3, and a rear foil 6 attached to the hull 2 ​​via a rear strut 5. The front foil 4 and the rear foil 6 are hydrofoils that generate lift in water. The hydrofoil vessel 100 is switchable between a propelled state in which the weight of the vessel is supported by the buoyancy of the hull 2, and a foil-propelled state in which the hull 2 ​​floats above the water surface due to the lift generated by the front foil 4 and the rear foil 6.

[0013] Hereinafter, the fore-and-aft direction will be defined as the front of the hydrofoil vessel 100 in the direction of travel, with the rear defined as the "rear." The right side of the hydrofoil vessel 100 when facing forward in the direction of travel will be defined as the "right" and the left side as the "left," and the left and right directions, i.e., the width direction, will be defined as the "up-down direction." The height direction of the hydrofoil vessel 100 will be defined as the "up-and-down direction." Unless otherwise specified, the "fore-and-aft direction" means the fore-and-aft direction of the hydrofoil vessel 100, and the "width direction" means the width direction of the hydrofoil vessel 100. Furthermore, the front of the hull 2 ​​means the front half when the hull 2 ​​is divided into two equal parts in the fore-and-aft direction. The rear of the hull 2 ​​means the rear half when the hull 2 ​​is divided into two equal parts in the fore-and-aft direction.

[0014] Fig. 3 is a side view of the hydrofoil vessel 100 as seen from the right side. In Fig. 3, the water surface W is shown, with the solid line representing the water surface W when the foil is propelled and the two-dot chain line representing the water surface W when the boat is propelled.

[0015] As shown in Figure 3, the hull 2 ​​has a bottom 21. In this example, the bottom 21 is of a so-called straight V type. That is, the bottom 21 has a ridge 22 that extends from the bow to the stern in the center of the width direction and protrudes downward. The ridge 22 defines the lowest part of the bottom 21. However, the rearmost part of the bottom 21, behind the rear strut 5, is formed by a horizontal plane, forming a so-called flat bottom. Hereinafter, the part of the bottom 21 that has the ridge 22 will be referred to as the V-shaped part 23, and the part formed by the horizontal plane will be referred to as the flat part 24.

[0016] 4 is a perspective view of the front and rear struts and foils of the hydrofoil vessel 100. In this example, the hydrofoil vessel 100 is equipped with one front strut 3. The front strut 3 is provided at the front of the hull 2, in the center in the width direction. The upper end of the front strut 3 is connected to the hull 2, more specifically, to the bottom 21 of the vessel.

[0017] The front strut 3 is configured to be switchable between a first state (see FIG. 3) in which the front foil 4 is positioned at a first position where lift is generated, and a second state (not shown) in which the front foil 4 is positioned at a second position higher than the first position. Specifically, the front strut 3 is mounted on the hull 2 ​​so as to rotate in the fore-and-aft direction, i.e., so as to rotate around an axis extending in the width direction.

[0018] In the first state, the front strut 3 extends downward from the bottom 21 of the vessel. The first state can also be referred to as the in-use state. In the second state, the front strut 3 rotates forward from the first state and extends forward from the bottom 21 of the vessel. The second state is a state in which the front strut 3 and the front foil 4 are brought closer to the hull 2, and can also be referred to as the stored state. Furthermore, the front strut 3 is mounted on the hull 2 ​​so that it can rotate not only in the fore-and-aft direction but also around its axis. Hereinafter, unless otherwise specified, when describing the configuration of the front strut 3 and other components, the front strut 3 will be considered to be in the first state.

[0019] 4, the front foils 4 extend to the left and right from the lower ends of the front struts 3. In other words, the front foils 4 are supported by the front struts 3.

[0020] A plurality of front flaps 41 are provided at the rear end of the front foil 4. The front flaps 41 are provided so as to be rotatable about axes extending in the width direction of the hull 2. The lift force generated by the front foil 4 is adjusted by the rotation of the front flaps 41.

[0021] In this example, the hydrofoil vessel 100 has at least two aft struts 5, more specifically, three aft struts 5, arranged side by side in the width direction of the hull 2. The upper ends of the aft struts 5 are connected to the hull 2, more specifically, to the bottom 21 of the hull.

[0022] The three aft struts 5 are arranged side by side in the width direction at the rear of the hull 2, i.e., in the rear half of the hull 2 ​​when it is divided into two equal parts in the fore-and-aft direction. The aft struts 5 are configured to be switchable between a first state (see FIG. 3 ) in which the aft foil 6 is positioned at a first position where lift is generated, and a second state (not shown) in which the aft foil 6 is positioned at a second position higher than the first position. Specifically, the aft struts 5 are mounted on the hull 2 ​​so as to rotate in the fore-and-aft direction, i.e., so as to rotate around an axis extending in the width direction.

[0023] In the first state, the aft strut 5 extends downward from the bottom 21 of the hull. The first state can also be referred to as the in-use state. In the second state, the aft strut 5 rotates rearward from the first state and extends rearward from the bottom 21 of the hull. The second state is a state in which the aft strut 5 and the aft foil 6 are brought close to the hull 2, and can also be referred to as the stored state. Hereinafter, when distinguishing between the three aft struts 5, they will be referred to as the left aft strut 5, the central aft strut 5, and the right aft strut 5, from the left.

[0024] As shown in Figure 4, the rear foil 6 is provided at the lower ends of the three rear struts 5. Specifically, the rear foil 6 extends left and right so as to connect the lower end of the left rear strut 5 with the lower end of the central rear strut 5, and the rear foil 6 extends left and right so as to connect the lower end of the right rear strut 5 with the lower end of the central rear strut 5. In other words, the rear foil 6 is supported by the rear struts 5.

[0025] A plurality of rear flaps 61 are provided at the rear end of the rear foil 6. The rear flaps 61 are provided so as to be rotatable about axes extending in the width direction. The rotation of the rear flaps 61 adjusts the lift force generated by the rear foil 6.

[0026] When the hydrofoil is propelled, the front strut 3 and the rear strut 5 may be in either the first state or the second state, or one of the front strut 3 and the rear strut 5 may be in the first state and the other in the second state. When the hydrofoil is propelled, both the front strut 3 and the rear strut 5 are in the first state, as shown in Figure 3. In other words, the hydrofoil vessel 100 is a so-called fully submerged hydrofoil vessel in which the front foil 4 and the rear foil 6 are entirely submerged below the water surface W when propelled.

[0027] Furthermore, when the hydrofoil vessel 100 is turning, the front strut 3 rotates around its axis to balance the vessel during turning. In other words, the front strut 3 has the function of supporting the front foil 4 and also functions as a rudder.

[0028] As shown in Fig. 4, the hydrofoil vessel 100 is equipped with a propulsion system 7. The propulsion system 7 is mounted inside the hull 2 ​​and propels the hull 2. In this example, the propulsion system 7 is equipped with two sets of jet pumps 71 and engines 72. One jet pump 71 and one engine 72 make up one set.

[0029] The two jet pumps 71 are arranged on the left and right sides at the rear and bottom of the hull 2. A water intake 51 that opens forward is provided at the lower end of the central aft strut 5. The upper end of the central aft strut 5 branches into two branches that are each connected to two jet pumps 71. A water supply passage is formed inside the central aft strut 5. Water flows from the water intake 51 into the central aft strut 5, flows through the water supply passage, and flows into each of the two jet pumps 71.

[0030] The two engines 72 are disposed on the left and right sides of the rear of the hull 2. Each engine 72 is connected to a jet pump 71 via a reduction gear in a gearbox 72a.

[0031] The jet pump 71 is an axial water jet pump. The jet pump 71 ejects water flowing in from the central rear strut 5 rearward, propelling the hull 2 ​​forward. The engine 72 drives the jet pump 71. The engine 72 is driven by fuel in a fuel tank 74, which will be described later. In other words, the engine 72 drives the jet pump 71 to propel the hull 2.

[0032] In this example, the engine 72 is a gas turbine engine. In a gas turbine engine, fuel is injected into compressed air and burned to rotate a turbine, generating torque as power. The jet pump 71 is driven by the torque of the engine 72.

[0033] Fig. 5 is a schematic diagram showing the propulsion system 7 in the first operating mode. Fig. 6 is a schematic diagram showing the propulsion system 7 in the second operating mode. Note that the jet pump 71 and the gear box 72a are omitted from Figs. 5 and 6.

[0034] The propulsion system 7 also has a fuel supply system that supplies fuel from a fuel tank 74 to the engine 72. Specifically, as shown in Fig. 5, the propulsion system 7 has, as the fuel supply system, the fuel tank 74, a fuel flow path 73, a first pump 77, a flow control valve 78, and an ejector 79. The flow path 73 has a first flow path 73a, a second flow path 73b, and a third flow path 73c.

[0035] The fuel tank 74 stores fuel to be supplied to the engine 72, i.e., fuel for driving the engine 72. In this example, the fuel is oil such as diesel. As shown in FIG. 3, a bottom surface 74a of the fuel tank 74 is located below the engine 72. The engine 72 and the fuel tank 74 are provided on the bottom 21 of the hull 2. More specifically, the fuel tank 74 is provided in the V-shaped portion 23, and the engine 72 is provided in the flat portion 24, which is higher than the V-shaped portion 23. In other words, the fuel in the fuel tank 74 is not supplied to the engine 72 by its own weight alone.

[0036] Two sets of the second flow path 73b, the third flow path 73c, the first pump 77, the flow control valve 78, and the ejector 79 are provided corresponding to the two engines 72, respectively.

[0037] The first pump 77 is a fuel pump driven by the engine 72. In other words, the first pump 77 is not an electrically driven fuel pump. Specifically, a drive shaft of the first pump 77 is connected to an output shaft of the engine 72, and the first pump 77 is driven by the rotational force of the engine 72. In other words, in this example, the jet pump 71 and the first pump 77 are driven by the rotational force of the engine 72. The first pump 77 is also called a so-called attached pump, which is attached to a gas turbine engine.

[0038] The second flow path 73b is a circulation flow path in which both ends are connected to the first pump 77 and in which the fuel is circulated by the first pump 77. That is, one end of the second flow path 73b, which is an inlet end, is connected to an outlet 77b of the first pump 77, and the other end of the second flow path 73b, which is an outlet end, is connected to an inlet 77a of the first pump 77. The first pump 77 circulates the fuel in the second flow path 73b.

[0039] The flow control valve 78 distributes a portion of the fuel in the second flow path 73b to the engine 72. The flow control valve 78 is an example of a distribution mechanism. The flow control valve 78 is provided in the second flow path 73b. Specifically, the flow control valve 78 is provided downstream of the first pump 77 in the second flow path 73b, more specifically, at a position closer to the outlet 77b than to the inlet 77a in the second flow path 73b.

[0040] The flow control valve 78 supplies a portion of the fuel circulating through the second flow path 73b, i.e., the fuel discharged from the first pump 77, to the engine 72 via the third flow path 73c, and circulates the remaining fuel through the second flow path 73b. The third flow path 73c is connected between the flow control valve 78 and the engine 72. The flow control valve 78 diverts the fuel at a flow rate necessary to drive the engine 72 from the second flow path 73b. In other words, the flow control valve 78 adjusts the flow rate of the fuel distributed to the engine 72.

[0041] The ejector 79 is provided in the second flow path 73b, and the fuel in the second flow path 73b flows therethrough as a driving fluid, and the suction port 79c of the ejector 79 communicates with the fuel tank 74 via the first flow path 73a. An inlet end, which is one end of the first flow path 73a, is connected to the fuel tank 74, and an outlet end, which is the other end of the first flow path 73a, is connected to the suction port 79c. More specifically, the outlet end of the first flow path 73a branches into two, which are connected to the suction ports 79c of the two ejectors 79, respectively.

[0042] More specifically, the ejector 79 is provided in the second flow path 73b between the inlet 77a of the first pump 77 and the flow control valve 78. That is, the flow control valve 78 and the ejector 79 are provided in the second flow path 73b in this order from the outlet 77b of the first pump 77. The ejector 79 has an inlet 79a and an outlet 79b in addition to an intake port 79c. In the ejector 79, fuel, which serves as a driving fluid, flows in through the inlet 79a and flows out through the outlet 79b, generating a suction effect at the intake port 79c. Therefore, fuel from the fuel tank 74 can be drawn into the intake port 79c via the first flow path 73a. That is, when the first pump 77 circulates fuel in the second flow path 73b, the fuel from the fuel tank 74 is supplied to the second flow path 73b and, ultimately, to the engine 72.

[0043] The propulsion system 7 is provided with a motor 81 that starts the engine 72. Specifically, the motor 81 is connected to the engine 72 and also connected to the first pump 77 directly or via a gear device (not shown) or the like. That is, the motor 81 drives the engine 72 and the first pump 77 simultaneously. The motor 81 increases the rotation speeds of the engine 72 and the first pump 77 to an initial rotation speed required to start the engine 72. The engine 72 is then started and operates by burning fuel. After the engine 72 has started, the first pump 77 is driven by the power of the engine 72. The motor 81 can be of various types, such as a hydraulic, electric, or pneumatic type.

[0044] The propulsion system 7 further includes a second pump 75, a filter 76, a fourth flow path 73d, and a check valve 82. That is, the flow path 73 further includes a fourth flow path 73d.

[0045] The second pump 75 is an electric fuel pump that is provided in the first flow path 73a and supplies fuel from the fuel tank 74 to the suction port 79c of the ejector 79. The second pump 75 is a positive displacement pump. For example, the second pump 75 is a gear pump or a screw pump. When the positive displacement pump is stopped, fuel cannot flow.

[0046] The filter 76 is provided in the first flow path 73a and separates and removes foreign matter contained in the fuel. More specifically, the filter 76 is provided in a portion of the first flow path 73a that is downstream of the second pump 75. That is, the filter 76 separates and removes foreign matter contained in the fuel discharged from the second pump 75.

[0047] The fourth flow path 73d is connected to the first flow path 73a and is a bypass flow path that bypasses the second pump 75. More specifically, the fourth flow path 73d bypasses the second pump 75 and the filter 76. An inlet end, which is one end of the fourth flow path 73d, is connected to the first flow path 73a on the upstream side of the second pump 75, and an outlet end, which is the other end of the fourth flow path 73d, is connected to the first flow path 73a on the downstream side of the filter 76. In other words, the fourth flow path 73d is in communication with the fuel tank 74 and the suction port 79c of the ejector 79.

[0048] The check valve 82 opens and closes the fourth flow path. The check valve 82 is an example of an on-off valve. The check valve 82 is provided in the fourth flow path 73d. The check valve 82 allows fuel to flow only from the fuel tank 74 side toward the suction port 79c side of the ejector 79 in the fourth flow path 73d.

[0049] More specifically, the check valve 82 opens when the fuel pressure in the portion of the first flow path 73a downstream of the second pump 75 falls below a threshold. Although not shown, for example, the check valve 82 has a biasing member that biases the valve element in the valve opening direction, and when the fuel pressure falls below the threshold, the valve element opens against the biasing force of the biasing member. This threshold is set to a value that can reduce the pressure in the portion of the first flow path 73a downstream of the second pump 75, for example, when the second pump 75 becomes inoperable for some reason and stops during operation.

[0050] The propulsion system 7 further includes a fifth flow path 73e and a pressure regulating valve 83. That is, the flow path 73 further includes a fifth flow path 73e.

[0051] The fifth flow path 73e is a return flow path that returns the fuel in the first flow path 73a to the fuel tank 74. The fifth flow path 73e is connected to the fuel tank 74 and a portion of the first flow path 73a downstream of the second pump 75. More specifically, the fifth flow path 73e is connected to a portion of the first flow path 73a downstream of the filter 76. That is, an inlet end, which is one end of the fifth flow path 73e, is connected to a portion of the fourth flow path 73d downstream of the check valve 82. An outlet end, which is the other end of the fifth flow path 73e, is connected to the fuel tank 74.

[0052] The pressure regulating valve 83 is provided in the fifth flow path 73e. The pressure regulating valve 83 returns the flow rate of the fuel discharged by the second pump 75 that is not consumed by the engine 72 to the fuel tank 74, while regulating the pressure of the first flow path 73a, i.e., the pressure at the suction port 79c, to a predetermined value.

[0053] The propulsion system 7 further comprises a pressure sensor 85 and a control device 86 .

[0054] The pressure sensor 85 detects the fuel pressure in a portion of the first flow path 73a downstream of the second pump 75. The pressure sensor 85 is provided in a portion of the first flow path 73a downstream of the second pump 75, more specifically, in a portion downstream of the filter 76. The pressure sensor 85 is capable of communicating with the control device 86 and transmits the detected fuel pressure to the control device 86. Hereinafter, unless otherwise specified, the term "detected pressure" refers to the fuel pressure detected by the pressure sensor 85.

[0055] The control device 86 controls the entire propulsion system 7, including the second pump 75, the flow control valve 78, the pressure regulating valve 83, the motor 81, and the like.

[0056] Furthermore, when the fuel pressure in the portion of the first flow path 73a downstream of the second pump 75 falls below the threshold, the control device 86 notifies the operator of the hydrofoil vessel 100 that the fuel pressure has fallen below the threshold. In other words, when the detected pressure transmitted from the pressure sensor 85 falls below the threshold, the control device 86 notifies the operator of this. The control device 86 is an example of an alarm unit. For example, the control device 86 notifies the operator by displaying the information on an operation screen or the like for the operator or by emitting a predetermined alarm sound.

[0057] The propulsion system 7 configured as described above is switchable between a first operating mode and a second operating mode. The first operating mode is a mode in which fuel is supplied to the engine 72 while driving the second pump 75. The second operating mode is a mode in which fuel is supplied to the engine 72 while the second pump 75 is stopped.

[0058] In the propulsion system 7 in the first operating mode, fuel is supplied from the fuel tank 74 to the engine 72, as shown by the arrows in Figure 5. Specifically, first, the motor 81 increases the rotation speed of the engine 72 and the first pump 77 to a predetermined rotation speed, and as a result, fuel begins to circulate in the second flow path 73b. At this time, the flow control valve 78 is set so as not to distribute fuel from the second flow path 73b to the engine 72. In other words, the entire amount of fuel discharged from the first pump 77 circulates in the second flow path 73b.

[0059] When the rotation speed of the first pump 77 increases to a predetermined initial rotation speed, the control device 86 controls the flow control valve 78 to distribute a portion of the fuel in the second flow path 73b to the engine 72 via the third flow path 73c. ​​In other words, when the pressure of the fuel circulating through the second flow path 73b increases to a pressure required to drive the engine 72, high-pressure fuel is distributed from the second flow path 73b to the engine 72. In this way, the engine 72 is driven. Accordingly, the first pump 77 is driven by the engine 72.

[0060] In the second flow path 73b, the first pump 77 circulates the fuel, which generates a suction effect at the suction port 79c of the ejector 79. Therefore, the fuel is sucked from the first flow path 73a to the suction port 79c. The fuel sucked into the suction port 79c is circulated through the second flow path 73b by the first pump 77.

[0061] Meanwhile, immediately before or at the same time as starting the engine 72, the second pump 75 is driven by the control device 86. Then, the second pump 75 supplies fuel from the fuel tank 74 to the suction ports 79c of the two ejectors 79 via the first flow path 73a. In the first flow path 73a, foreign matter contained in the fuel is separated and removed when the fuel discharged from the second pump 75 passes through the filter 76. Therefore, clean fuel is supplied to the suction ports 79c.

[0062] As described above, in the first operating mode, the second pump 75 supplies fuel from the fuel tank 74 to the suction port 79c, and the suction port 79c draws fuel from the second pump 75. That is, the pumping action of the second pump 75 and the suction action of the ejector 79 cause the fuel from the fuel tank 74 to be supplied to the second flow path 73b and ultimately to the engine 72. In this way, in the second flow path 73b, a portion of the circulating fuel is supplied to the engine 72, while the fuel from the fuel tank 74 is replenished. This allows the engine 72 to operate normally.

[0063] In the first operating mode, the pressure of the first flow path 73a is controlled by the pressure control valve 83. That is, the pressure of the fuel supplied from the fuel tank 74 to the suction port 79c of the ejector 79 is adjusted by the pressure control valve 83. This allows fuel at an appropriate pressure to be supplied to the second flow path 73b.

[0064] In the first operating mode, if the second pump 75 becomes inoperable, i.e., stops, due to a power outage, for example, the operating mode automatically switches to the second operating mode. In the second operating mode, the propulsion system 7 supplies fuel from the fuel tank 74 to the engine 72, as shown by the arrow in Figure 6.

[0065] Specifically, when the second pump 75 stops, the check valve 82 automatically opens. More specifically, when the second pump 75 stops, the fuel pressure in the portion of the first flow path 73a downstream of the second pump 75 drops below the threshold, i.e., below the pressure at which the check valve 82 opens, causing the check valve 82 to open. In other words, in the portion of the first flow path 73a downstream of the second pump 75, the pressure drops suddenly below the threshold due to the suction action of the suction port 79c in addition to the second pump 75 stopping. Therefore, the check valve 82 opens substantially simultaneously with the stopping of the second pump 75.

[0066] On the other hand, the first pump 77 does not stop even in the event of a power outage because it is driven by the engine 72. Therefore, fuel continues to circulate in the second flow path 73b, and the suction action at the suction port 79c of the ejector 79 continues.

[0067] When the check valve 82 opens in this manner, the fuel tank 74 and the suction port 79c are connected via the first flow path 73a and the fourth flow path 73d. Therefore, fuel from the fuel tank 74 is drawn into the suction port 79c. The fuel drawn into the suction port 79c is circulated through the second flow path 73b by the first pump 77. Then, a portion of the fuel circulating through the second flow path 73b is distributed to the engine 72, as in the first operating mode. In this manner, the fuel from the fuel tank 74 is continuously supplied to the second flow path 73b and, ultimately, to the engine 72.

[0068] Furthermore, when the pressure detected by the pressure sensor 85 falls below the threshold, the control device 86 notifies the operator of the hydrofoil vessel 100. This allows the operator to quickly understand that the second pump 75 has stopped. Therefore, the operator can quickly deal with the stoppage of the second pump 75.

[0069] As described above, the propulsion system 7 of the hydrofoil vessel 100 includes the second flow path 73b through which the first pump 77 driven by the engine 72 circulates fuel, the flow control valve 78 that distributes a portion of the fuel in the second flow path 73b to the engine 72, and the ejector 79 through which the fuel in the second flow path 73b flows as a driving fluid and whose suction port 79c communicates with the fuel tank 74 via the first flow path 73a. Therefore, even in the event of a power outage, a suction action occurs at the suction port 79c of the ejector 79, so that fuel in the fuel tank 74 continues to be drawn into the suction port 79c. Therefore, fuel can be continuously supplied to the engine 72 even in the event of a power outage without providing an emergency fuel tank for use in the event of a power outage, i.e., a fuel tank that is located higher than the engine 72 and from which fuel is supplied to the engine 72 by its own weight alone.

[0070] Furthermore, the engine 72 is a gas turbine engine. Compared to, for example, a diesel engine, a gas turbine engine starts combustion at a higher rotation speed. Therefore, the operating rotation speed of the first pump 77 also increases, and the pressure of the fuel in the second flow path 73b increases. This increases the suction force generated at the suction port 79c of the ejector 79. Therefore, for example, even if the length of the first flow path 73a is long or the difference in elevation between the engine 72 and the fuel tank 74 is large, the suction port 79c can draw fuel from the fuel tank 74.

[0071] The propulsion system 7 also includes an electric second pump 75 that is provided in the first flow path 73a and supplies fuel from the fuel tank 74 to the suction port 79c. Therefore, even if the suction force of the suction port 79c becomes insufficient, for example, if the fuel level in the fuel tank 74 drops and it becomes difficult for the suction port 79c to suck in the fuel, the fuel from the fuel tank 74 is still supplied to the second flow path 73b.

[0072] Furthermore, because second pump 75 is a positive displacement pump, even if fuel tank 74 is provided at a lower position than second pump 75, fuel in fuel tank 74 can be easily pumped up by second pump 75. This increases the degree of freedom in the placement of fuel tank 74 and the like.

[0073] Furthermore, the first flow path 73a is provided with a fourth flow path 73d that bypasses the second pump 75, and the fourth flow path 73d is provided with an on-off valve that opens and closes the fourth flow path 73d. The second pump 75 is a positive displacement pump, and when the second pump 75 is stopped, the fuel cannot flow. In this example, when the second pump 75 stops due to a power outage or the like, the on-off valve can be opened to supply fuel from the fuel tank 74 to the suction port 79c via the fourth flow path 73d.

[0074] Furthermore, the on-off valve provided in the fourth flow path 73d opens when the fuel pressure in the portion of the first flow path 73a downstream of the second pump 75 falls below a threshold. If the second pump 75 stops due to a power outage or the like, the suction action of the suction port 79c also causes the fuel pressure in the portion of the first flow path 73a downstream of the second pump 75 to fall below the threshold. Therefore, when the second pump 75 stops, the on-off valve automatically opens. This eliminates the need for manual operation of the on-off valve.

[0075] In particular, the on-off valve is a check valve 82. Therefore, the check valve 82 can be automatically opened without electrical communication, which allows the number of parts to be reduced.

[0076] Furthermore, a filter 76 that separates and removes foreign matter contained in the fuel is provided in the first flow path 73a in which the second pump 75 is provided. This allows clean fuel from which foreign matter has been separated and removed to be supplied to the second flow path 73b and ultimately to the engine 72. However, providing the filter 76 increases pressure loss in the first flow path 73a. This may make it difficult for the suction port 79c to sufficiently suck fuel from the fuel tank 74. However, in this example, the provision of the second pump 75 allows the fuel from the fuel tank 74 to be sufficiently supplied to the suction port 79c.

[0077] The propulsion system 7 is also provided with a control device 86 that notifies the pilot when the fuel pressure in the portion of the first flow path 73a downstream of the second pump 75 falls below a threshold. This allows the pilot to quickly understand that the second pump 75 has stopped. This allows the pilot to quickly take action regarding the stoppage of the second pump 75.

[0078] Furthermore, the bottom surface 74a of the fuel tank 74 is located below the engine 72. Therefore, the propulsion system 7 can be easily arranged in the hydrofoil vessel 100, in which the space above the engine 72 is extremely limited.

[0079] Other Embodiments As described above, the above embodiment has been described as an example of the technology disclosed in this application. However, the technology of the present disclosure is not limited to this and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate. Furthermore, the components described in the above embodiment can be combined to create new embodiments. Furthermore, the components described in the accompanying drawings and detailed description may include not only components essential for solving the problem, but also components that are not essential for solving the problem in order to exemplify the technology. Therefore, the fact that these non-essential components are described in the accompanying drawings or detailed description should not be interpreted as immediately determining that these non-essential components are essential.

[0080] For example, the propulsion system of the hydrofoil vessel 100 of the present disclosure may have the configuration shown in FIG. 7 . FIG. 7 is a schematic diagram showing a propulsion system 7A according to another embodiment. Note that the jet pump 71 and gearbox 72a are not shown in FIG. 7 . This propulsion system 7A is similar to the propulsion system 7 of the above-described embodiment in that the second pump 75, filter 76, fourth flow path 73d, fifth flow path 73e, and pressure regulating valve 83 are omitted. This propulsion system 7A has only the second operating mode of the above-described embodiment. That is, in this propulsion system 7A, fuel in the fuel tank 74 is drawn into the suction port 79c of the ejector 79 via the first flow path 73a regardless of whether there is a power outage or not. The operation of the second flow path 73b and the operation of the first pump 77 are the same as those of the above-described embodiment. This example also achieves the same effects as those of the above-described embodiment.

[0081] Furthermore, the engine 72 is not limited to a gas turbine engine, but may be, for example, a diesel engine.

[0082] Furthermore, in the propulsion system 7, the fifth flow path 73e and the pressure adjustment valve 83 may be omitted.

[0083] Furthermore, the on-off valve provided in the fourth flow path 73d is not limited to the check valve 82, but may be, for example, a solenoid valve, an electric valve, or the like.

[0084] Furthermore, the function of the notification unit may be omitted from the control device 86.

[0085] As described above, the propulsion system 7, 7A of the hydrofoil vessel 100 relating to the first aspect of the technology of the present disclosure comprises a fuel tank 74, an engine 72 driven by fuel in the fuel tank 74 and propelling the hull 2 ​​of the hydrofoil vessel 100, a first pump 77 driven by the engine 72, a second flow path 73b connected at both ends to the first pump 77 and through which fuel is circulated by the first pump 77, a flow control valve 78 that distributes a portion of the fuel in the second flow path 73b to the engine 72, and an ejector 79 provided in the second flow path 73b, through which the fuel in the second flow path 73b circulates as a driving fluid and whose suction port 79c is connected to the fuel tank 74 via the first flow path 73a.

[0086] According to this configuration, even in the event of a power outage, a suction action occurs at the suction port 79c of the ejector 79, so that fuel continues to be drawn into the suction port 79c from the fuel tank 74. Therefore, fuel can be continuously supplied to the engine 72 even in the event of a power outage without providing an emergency fuel tank for use in the event of a power outage.

[0087] Furthermore, the propulsion system 7, 7A of the hydrofoil ship 100 according to the second aspect of the technique of the present disclosure is the propulsion system 7, 7A of the hydrofoil ship 100 according to the first aspect, in which the engine 72 is a gas turbine engine.

[0088] According to this configuration, since a gas turbine engine starts combustion at a higher rotation speed than, for example, a diesel engine, the operating rotation speed of the first pump 77 also increases, and the pressure of the fuel in the second flow path 73b increases. This increases the suction force generated at the suction port 79c of the ejector 79. This allows the suction port 79c to reliably draw fuel from the fuel tank 74.

[0089] In addition, the propulsion system 7, 7A of the hydrofoil vessel 100 relating to the third aspect of the technology of the present disclosure further includes an electric second pump 75 provided in the first flow path 73a in the propulsion system 7 of the hydrofoil vessel 100 relating to the first or second aspect, which supplies fuel from the fuel tank 74 to the suction port 79c of the ejector 79.

[0090] According to this configuration, even if the suction force of the suction port 79c becomes insufficient, the fuel in the fuel tank 74 can be easily supplied to the second flow path 73b.

[0091] In addition, the propulsion system 7 of the hydrofoil vessel 100 relating to a fourth aspect of the technology of the present disclosure is a propulsion system 7 of the hydrofoil vessel 100 relating to any one of the first to third aspects, in which the second pump 75 is a positive displacement pump and further includes a fourth flow path 73d connected to the first flow path 73a and bypassing the second pump 75, and an opening / closing valve for opening and closing the fourth flow path 73d.

[0092] According to this configuration, because the second pump 75 is a positive displacement pump, even if the fuel tank 74 is located lower than the second pump 75, the second pump 75 can easily pump up fuel from the fuel tank 74. This increases the flexibility in the placement of the fuel tank 74 and other components. Furthermore, the first flow path 73a is provided with a fourth flow path 73d that bypasses the second pump 75, and the fourth flow path 73d is provided with an on-off valve that opens and closes the fourth flow path 73d. Because the second pump 75 is a positive displacement pump, the second pump 75 cannot circulate fuel when it is stopped. With the technology disclosed herein, if the second pump 75 stops due to a power outage or the like, the on-off valve can be opened to supply fuel from the fuel tank 74 to the suction port 79c via the fourth flow path 73d.

[0093] In addition, in the propulsion system 7 of the hydrofoil vessel 100 relating to the fifth aspect of the technology disclosed herein, in the propulsion system 7 of the hydrofoil vessel 100 relating to the fourth aspect, the opening / closing valve opens when the fuel pressure in the portion of the first flow path 73a downstream of the second pump 75 falls below a threshold value.

[0094] According to this configuration, when the second pump 75 stops due to a power outage or the like, the suction action of the suction port 79c also causes the fuel pressure in the portion of the first flow path 73a downstream of the second pump 75 to drop below the threshold. Therefore, when the second pump 75 stops, the on-off valve automatically opens. This eliminates the need for manual operation of the on-off valve.

[0095] In addition, the propulsion system 7 of the hydrofoil vessel 100 relating to the fifth aspect of the technology disclosed herein is the propulsion system 7 of the hydrofoil vessel 100 relating to the third aspect, and further comprises a filter 76 provided in the first flow path 73a to separate and remove foreign matter contained in the fuel.

[0096] According to this configuration, clean fuel from which foreign matter has been separated and removed can be supplied to the second flow path 73b and, ultimately, to the engine 72. On the other hand, providing the filter 76 increases pressure loss in the first flow path 73a. This may make it difficult for the suction port 79c to sufficiently draw fuel from the fuel tank 74. However, in this example, the second pump 75 is provided, so that the fuel from the fuel tank 74 can be sufficiently supplied to the suction port 79c. In other words, because the second pump 75 is provided in the first flow path 73a, the filter 76 can be provided in the first flow path 73a without being too concerned about pressure loss in the first flow path 73a.

[0097] In addition, the propulsion system 7 of the hydrofoil vessel 100 relating to the seventh aspect of the technology disclosed herein is further provided with a control device 86 that, in the propulsion system 7 of the hydrofoil vessel 100 relating to any one of the third to sixth aspects, notifies the operator of the hydrofoil vessel that the fuel pressure in the portion of the first flow path 73a downstream of the second pump 75 has fallen below a threshold value.

[0098] This configuration allows the operator to quickly recognize that the second pump 75 has stopped, and therefore allows the operator to quickly deal with the stoppage of the second pump 75.

[0099] In addition, the propulsion system 7 of the hydrofoil vessel 100 relating to the eighth aspect of the technology disclosed herein is a propulsion system 7, 7A of the hydrofoil vessel 100 relating to any one of the first to seventh aspects, in which the bottom surface 74a of the fuel tank 74 is located below the engine 72.

[0100] According to this configuration, the propulsion system 7 can be easily installed on the hydrofoil vessel 100 in which the space above the engine 72 is extremely limited.

[0101] A hydrofoil vessel 100 according to a ninth aspect of the technique of the present disclosure includes a hull 2 ​​and a propulsion system 7, 7A according to any one of the first to eighth aspects mounted on the hull 2.

[0102] This configuration provides the same advantages as the propulsion systems 7, 7A of the hydrofoil vessel 100 according to the first aspect. [Explanation of symbols]

[0103] 100 Hydrofoil 2. Hull 7,7A Propulsion System 72 Gas Turbine Engine (Engine) 73a First flow path 73b Second flow path 73d 4th Channel 74 Fuel Tank 74a Bottom 75 Second Pump 76 filters 77 First Pump 78 Flow control valve (distribution mechanism) 79 Ejector 79c Suction port 82 Check valve (on-off valve) 86 Control device (alarm unit)

Claims

1. A fuel tank and an engine driven by the fuel in the fuel tank to propel the hull of the hydrofoil vessel; a first pump driven by the engine; a second flow path having both ends connected to the first pump and through which fuel is circulated by the first pump; a distribution mechanism that distributes a portion of the fuel in the second flow path to the engine; A propulsion system for a hydrofoil vessel, comprising: an ejector provided in the second flow path, through which fuel in the second flow path flows as a driving fluid, and whose suction port communicates with the fuel tank via the first flow path.

2. 2. The hydrofoil propulsion system of claim 1, A hydrofoil propulsion system, wherein the engine is a gas turbine engine.

3. 3. A hydrofoil propulsion system according to claim 1, a second electric pump provided in the first flow path and configured to supply fuel from the fuel tank to a suction port of the ejector.

4. 4. A hydrofoil propulsion system according to claim 3, the second pump is a positive displacement pump; a fourth flow path connected to the first flow path and bypassing the second pump; and an on-off valve that opens and closes the fourth flow path.

5. 5. A hydrofoil propulsion system according to claim 4, A propulsion system for a hydrofoil vessel, wherein the on-off valve opens when fuel pressure in a portion of the first flow path downstream of the second pump becomes equal to or lower than a threshold value.

6. 4. A hydrofoil propulsion system according to claim 3, The hydrofoil propulsion system further comprises a filter provided in the first flow path for separating and removing foreign matter contained in the fuel.

7. 4. A hydrofoil propulsion system according to claim 3, A hydrofoil propulsion system further comprising an alarm unit that, when the fuel pressure in the portion of the first flow path downstream of the second pump falls below a threshold, alerts the operator of the hydrofoil that the fuel pressure has fallen below a threshold.

8. 3. A hydrofoil propulsion system according to claim 1, A propulsion system for a hydrofoil vessel, wherein the bottom of the fuel tank is located below the engine.

9. The hull and A hydrofoil vessel comprising the propulsion system according to claim 1 or 2 mounted on the hull.

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