Hydrogen engine

Abstract

To properly cope with leakage of hydrogen gas in a hydrogen engine for a ship.SOLUTION: The hydrogen engine 1 includes a plurality of gas supply means 49 provided in each cylinder 16, a plurality of leakage sensors 52 provided at least in the same number as the plurality of cylinders 16, and a controller 100. Based on the detection signals of the plurality of leak sensors 52, the controller 100 determines whether or not hydrogen gas is leaking and estimates the specific cylinder from the plurality of cylinders, and if hydrogen gas is leaking, the controller 100 continues the operation of the hydrogen engine 1 while reducing or eliminating the amount of hydrogen gas supplied to the specific cylinder via the plurality of gas supply means 49.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present disclosure relates to a hydrogen engine for a ship. [Background technology]

[0002] Patent Document 1 discloses a hydrogen supply device for a vehicle. Specifically, this hydrogen supply device includes a hydrogen engine, a tank filled with hydrogen gas, an on-off valve that switches the supply of hydrogen gas from the tank to the hydrogen engine, and a hydrogen sensor that detects hydrogen gas leaks.

[0003] Here, the hydrogen sensor includes a first hydrogen sensor and a second hydrogen sensor. The first hydrogen sensor is a hydrogen sensor for detecting leakage of hydrogen gas from a hydrogen supply device including a tank. The first hydrogen sensor is disposed in the storage space of the tank. The second hydrogen sensor is a hydrogen sensor for detecting leakage of hydrogen gas from a hydrogen engine. The second hydrogen sensor is disposed in the storage space of the hydrogen engine.

[0004] The hydrogen supply device disclosed in Patent Document 1 is configured so that the on-off valve will not open if hydrogen gas is leaking, thereby cutting off the supply of hydrogen gas from the tank to the hydrogen engine. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2024-021279 Summary of the Invention [Problem to be solved by the invention]

[0006] As described in Patent Document 1, it is known that when hydrogen gas leaks, the supply of hydrogen gas to a hydrogen engine is cut off. When the supply of hydrogen gas is cut off, the hydrogen engine stops operating.

[0007] In practice, when a hydrogen engine for a vehicle is shut down, it is sufficient to park it on the side of the road, etc. However, if a hydrogen engine for a ship stops completely, it may enter a so-called "dead ship state." This is inconvenient because it could lead to the ship capsizing, etc.

[0008] On the other hand, when considering the safety of hydrogen gas, it is still considered inconvenient if hydrogen gas leaks are not dealt with appropriately, even in hydrogen engines for ships rather than vehicles.

[0009] The present disclosure has been made in view of the above points, and an object thereof is to appropriately deal with hydrogen gas leakage in a hydrogen engine for a ship. [Means for solving the problem]

[0010] A first aspect of the present disclosure relates to a hydrogen engine for ships, which has a plurality of cylinders connected via a common crankshaft and burns hydrogen gas in each combustion chamber of the plurality of cylinders. The hydrogen engine comprises a plurality of gas supply means provided in each of the plurality of cylinders to supply hydrogen gas to each of the combustion chambers, a plurality of leak sensors provided in at least the same number as the plurality of cylinders, each of which outputs a signal indicating the presence or absence of hydrogen gas leakage in the plurality of gas supply means, and a controller connected to the plurality of gas supply means and the plurality of leak sensors to control the operation of the hydrogen engine.

[0011] According to the first aspect, one or more of the plurality of gas supply means in which a hydrogen gas leak has occurred are referred to as specific supply means, and one or more of the plurality of cylinders corresponding to the specific supply means are referred to as specific cylinders. During operation of the hydrogen engine, the controller determines whether or not a hydrogen gas leak has occurred based on a detection signal output from at least one of the plurality of leak sensors, and estimates the specific cylinder among the plurality of cylinders. If a hydrogen gas leak has occurred, the controller continues operation of the hydrogen engine while reducing or zeroing the amount of hydrogen gas supplied to the specific cylinder via the plurality of gas supply means.

[0012] According to the first aspect, by using at least the same number of leak sensors as the number of cylinders, it is possible to estimate which cylinder among the multiple cylinders corresponds to the specific cylinder. This makes it possible to properly identify the location of the hydrogen gas leak, even in hydrogen engines that can be relatively large, such as hydrogen engines for ships. This allows for appropriate countermeasures to be taken against the hydrogen gas leak.

[0013] By configuring the system to reduce or eliminate the amount of hydrogen gas supplied to specific cylinders rather than reducing or eliminating the amount of hydrogen gas supplied to all cylinders, it becomes possible to continue operating the hydrogen engine using other cylinders, thereby preventing the ship from falling into a dead ship state.

[0014] Thus, according to the first aspect, safety can be ensured when using hydrogen gas, and even if a hydrogen gas leak occurs, the ship can be prevented from becoming a dead ship.

[0015] Furthermore, according to a second aspect of the present disclosure, the hydrogen engine may include a leakage gas flow passage connected to each gas supply means of the plurality of cylinders and through which hydrogen gas leaked from each gas supply means flows, the plurality of leakage sensors detect the concentration of hydrogen gas in the leakage gas flow passage, and the controller may receive detection signals from each of the plurality of leakage sensors and estimate the specific cylinder based on one or more combinations of detection timings or detection values ​​of the detection signals corresponding to each of the plurality of leakage sensors.

[0016] Here, "one or more combinations of detection timings or detection values" may be a combination made up of one or more detection timings, or may be a combination made up of one or more detection values.

[0017] The second aspect is advantageous in that it allows for appropriate measures to be taken against leakage of hydrogen gas.

[0018] Furthermore, according to a third aspect of the present disclosure, the leakage gas flow passage may be configured to include a leakage gas shared path shared among the plurality of cylinders, at least one of the plurality of leakage sensors may be arranged in the leakage gas shared path, and the controller may estimate the specific cylinder based on the detection order of each detection signal or the order of high and low detection values.

[0019] In a configuration with a shared leak gas path, a hydrogen gas leak occurring in any cylinder may be detected by multiple leak sensors through that shared leak gas path. However, even if multiple leak sensors detect the leak, it is thought that there will be discrepancies in the detection order or detection values ​​of each leak sensor due to the flow of hydrogen gas through the shared leak gas path.

[0020] Therefore, as in the third aspect, the controller identifies the specific cylinder by utilizing the above-mentioned deviation. By configuring in this manner, it becomes possible to appropriately estimate the specific cylinder even when at least some of the leakage sensors are arranged in the shared leakage gas path.

[0021] Furthermore, according to a fourth aspect of the present disclosure, the leakage gas flow passage may be configured to include a plurality of leakage gas branch paths branched off for each cylinder so as to be connected to each gas supply means of the plurality of cylinders, the plurality of leakage sensors may be arranged in the plurality of leakage gas branch paths corresponding to each of the plurality of cylinders, and when the controller receives a detection signal from one or more of the plurality of leakage sensors indicating that hydrogen gas is leaking, the controller may estimate that the cylinder among the plurality of cylinders connected to the leakage gas branch path in which the leakage sensor that output the detection signal is arranged is the specific cylinder.

[0022] According to the fourth aspect, if a leakage sensor is provided in each leakage gas branch path, a hydrogen gas leak occurring in any cylinder will be detected by the leakage sensor provided in the leakage gas branch path corresponding to that cylinder. In other words, since there is a one-to-one correspondence between each leakage sensor and each cylinder, by utilizing this correspondence, it is possible to appropriately identify the specific cylinder.

[0023] According to a fifth aspect of the present disclosure, the hydrogen engine may be provided with a hydrogen gas flow passage connected to each combustion chamber of the plurality of cylinders, through which hydrogen gas to be supplied to each cylinder flows, the hydrogen gas flow passage including a plurality of hydrogen gas branch passages connected to each combustion chamber of the plurality of cylinders, the plurality of gas supply means each comprising a plurality of control valves that open and close the hydrogen gas flow passages provided in each of the plurality of cylinders, the plurality of control valves being inserted into components of the cylinders or separate parts attached to the components, and the plurality of leakage gas branch passages each communicating with a gap between the outer peripheral surface of each of the plurality of control valves and the inner peripheral surface of the component or the separate part.

[0024] According to the fifth aspect, it is possible to more appropriately deal with areas where hydrogen gas leakage is anticipated.

[0025] According to a sixth aspect of the present disclosure, a gas other than hydrogen gas may flow through the leaking gas flow passage.

[0026] According to the sixth aspect, when a hydrogen gas leak occurs, the hydrogen gas that has flowed into the leaking gas flow passage can be drawn into the gas flow in the leaking gas flow passage or swept away by the gas flow, thereby making it possible to more appropriately deal with the hydrogen gas leak.

[0027] Furthermore, according to a seventh aspect of the present disclosure, the hydrogen engine is provided with a hydrogen gas flow passage connected to each combustion chamber of the plurality of cylinders and through which hydrogen gas supplied to each cylinder flows, the leakage gas flow passage being configured to include a leakage gas shared passage shared among the plurality of cylinders and arranged outside the plurality of cylinders, the hydrogen gas flow passage being configured to include a plurality of hydrogen gas branch passages connected to each combustion chamber of the plurality of cylinders and a hydrogen gas shared passage shared among the plurality of cylinders and arranged outside the plurality of cylinders, and the hydrogen gas shared passage may be configured to be arranged within a pipe forming the leakage gas shared passage.

[0028] According to the seventh aspect, when hydrogen gas leaks in the hydrogen gas shared passage, the hydrogen gas can be sent to the leaked gas shared passage, thereby making it possible to deal with the hydrogen gas leak more appropriately.

[0029] Furthermore, according to an eighth aspect of the present disclosure, when a hydrogen gas leak occurs, the controller may continue operation of the hydrogen engine by reducing or eliminating the amount of hydrogen gas supplied to a specific cylinder among the plurality of cylinders, while maintaining or increasing the amount of hydrogen gas supplied to cylinders other than the specific cylinder.

[0030] According to the eighth aspect, the hydrogen engine can continue to operate by reducing or eliminating the supply of hydrogen gas to specific cylinders while maintaining or increasing the supply of hydrogen gas to other cylinders, thereby preventing the ship from becoming a dead ship.

[0031] Furthermore, according to a ninth aspect of the present disclosure, the hydrogen engine is switchable between a mode in which hydrogen gas is burned alone and a mode in which hydrogen gas and oil fuel are burned together, and the controller may be configured to continue operation of the hydrogen engine by supplying oil fuel instead of hydrogen gas to at least a specific cylinder among the plurality of cylinders in the event of a hydrogen gas leak.

[0032] According to the ninth aspect, by supplying oil fuel instead of hydrogen gas to the specific cylinder, it becomes possible to prevent leakage of hydrogen gas and continue operation of the specific cylinder. [Effects of the Invention]

[0033] As described above, according to the present disclosure, leakage of hydrogen gas can be appropriately dealt with in a hydrogen engine for a ship. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is a diagram illustrating a ship equipped with an engine system. [Figure 2] FIG. 2 is a side view illustrating the overall configuration of a hydrogen engine in an engine system. [Figure 3] FIG. 3 is a schematic diagram illustrating the configuration of a hydrogen engine. [Figure 4] FIG. 4 is a cross-sectional view that schematically illustrates an example of the upper structure of a hydrogen engine. [Figure 5] FIG. 5 is a schematic diagram for explaining the connection structure between the cylinders. [Figure 6] FIG. 6 is a schematic diagram for explaining the flow path structure of a hydrogen engine. [Figure 7] FIG. 7 illustrates a cross section taken along the line AA in FIG. 6. [Figure 8] FIG. 8 is a block diagram showing the configuration of the controller. [Figure 9] FIG. 9 is a flowchart illustrating the leak handling process. [Figure 10] FIG. 10 is a diagram corresponding to FIG. 5, illustrating a hydrogen engine according to a first modified example. [Figure 11] FIG. 11 is a diagram corresponding to FIG. 9, illustrating the leakage handling process according to the first modified example. [Figure 12] FIG. 12 is a diagram corresponding to FIG. 5, illustrating a hydrogen engine according to a second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0035] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Note that the following description is for illustrative purposes only.

[0036] <Overall structure> FIG. 1 is a diagram illustrating a ship 1000 equipped with an engine system S. FIG. 2 is a side view illustrating the overall configuration of a hydrogen engine (hereinafter also simply referred to as "engine") 1 in the engine system S. FIG. 3 is a schematic diagram illustrating the configuration of the engine 1. FIG. 4 is a cross-sectional view illustrating a schematic example of the upper structure of the hydrogen engine. The cross-section of FIG. 4 corresponds to the cross-section of one of the multiple cylinders 16 that make up the engine 1.

[0037] The engine system S is mounted on a ship 1000. As shown in Fig. 1, the engine system S includes an engine 1 that can use hydrogen gas as gas fuel, a hydrogen tank 2 that stores the hydrogen gas, a gas valve module 3 interposed between the engine 1 and the hydrogen tank 2, and a propeller shaft 1001 and a propeller 1002 connected to the crankshaft 23 of the engine 1.

[0038] The engine 1 has multiple cylinders 16 connected via a common crankshaft 23. The engine 1 is a hydrogen engine for ships that burns hydrogen gas in each combustion chamber 17 of the multiple cylinders 16. In other words, the engine 1 is an engine that uses hydrogen gas as gas fuel.

[0039] The engine 1 may be one that burns hydrogen gas alone, or one that burns hydrogen gas in combination with other oil fuel (for example, a mixture of hydrogen gas and heavy oil).The engine 1 may be an engine that can be switched between a mode in which hydrogen gas is burned alone and a mode in which hydrogen gas and oil fuel are burned together.

[0040] The engine 1 is configured as a uniflow scavenging two-stroke one-cycle engine, and is installed on a large ship 1000 such as a tanker, a container ship, or a car carrier. The engine 1 is used as the main engine for propelling the ship 1000. The output shaft (crankshaft 23) of the engine 1 is connected to a propeller 1002 of the ship via a propeller shaft 1001. When the engine 1 is operating, its output is transmitted to the propeller 1002, and the ship 1000 is propelled. In order to shorten the distance between the engine 1 and the propeller 1002, the engine 1 is disposed rearward of the hydrogen tank 2 in the fore-and-aft direction of the boat 1000. Note that the "fore-and-aft direction" here corresponds to the propulsion direction of the boat 1000.

[0041] Specifically, an engine room 1003 is defined inside the vessel 1000. The engine 1 is disposed in this engine room 1003. The gas valve train (GVT) 3 described above is disposed in front of the engine 1. The GVT 3 is disposed in the engine room 1003. The flow generator 54 described below is also disposed in front of the engine 1 (specifically, in front of the engine body 10). By disposing both the GVT 3 and the flow generator 54 on the front side, the space in front of the engine body 10 can be utilized without waste.

[0042] The GVT 3 connects the hydrogen tank 2 to the engine 1. The GVT 3 is a module made up of pipes through which hydrogen gas flows and a plurality of control valves that open and close the pipes. The opening and closing of each control valve in the GVT 3 is controlled by a controller 100 of the engine 1. In this embodiment, the GVT 3 is defined as an element independent of the engine 1, but it may also be considered as one of the elements that make up the engine 1.

[0043] <Main engine components> Fig. 5 is a schematic diagram for explaining the connection structure between cylinders 16. Fig. 6 is a schematic diagram for explaining the flow path structure of engine 1. Fig. 7 illustrates an example of a cross section taken along line AA in Fig. 6.

[0044] 2 to 6, the engine 1 includes an engine body 10 having a plurality of cylinders 16, a hydrogen gas supply system 4, a leakage gas circulation system 5, a hydrogen gas pipe 6, and a controller 100 connected to the engine body 10. Each cylinder 16 defines a combustion chamber 17 for burning gas fuel.

[0045] As shown in FIG. 2, a plurality of cylinders 16 (six in this embodiment) are provided so as to be aligned in the propulsion direction of the vessel 1000. Hereinafter, the alignment direction of the cylinders 16 will be referred to as the longitudinal direction, similar to the positional relationship between the hydrogen engine 1 and the hydrogen tank 2. Furthermore, the direction perpendicular to this longitudinal direction and the central axis Op (the central axis of the piston 21 inserted in each cylinder 16) illustrated in FIG. 4 will be referred to as the lateral direction. The longitudinal direction can be referred to as the "first direction." The lateral direction can be referred to as the "second direction."

[0046] Hereinafter, the six cylinders 16 may be referred to as the "first cylinder 16A," "second cylinder 16B," "third cylinder 16C," "fourth cylinder 16D," "fifth cylinder 16E," and "sixth cylinder 16F," in order from the rear of FIG. 1. (1) Engine body 10 As described above, the engine body 10 has a plurality of cylinders 16. The engine body 10 is a two-stroke engine and is installed in the engine room 1003 of the ship 1000. The following description applies to all six cylinders 16.

[0047] 3, the engine body 10 according to this embodiment is configured as a so-called crosshead type internal combustion engine in order to achieve a long stroke. That is, in this engine body 10, a piston rod 22 that supports a piston 21 from below and a connecting rod 24 that is connected to a crankshaft 23 are connected by a crosshead 25.

[0048] Specifically, the engine body 10 includes a bed plate 11 located below, a frame 12 provided on the bed plate 11, a cylinder jacket 13 provided on the frame 12, a cylinder liner 14, and a cylinder cover 15. Each cylinder 16 is provided inside the cylinder jacket 13. The engine body 10 also includes a piston 21 that is disposed in each cylinder 16 and reciprocates within the cylinder 16, and an output shaft (e.g., a crankshaft 23) that rotates in conjunction with the reciprocating motion of the piston 21.

[0049] Here, the base plate 11 constitutes the crankcase of the engine 1 and houses a crankshaft 23 and a bearing 26 that rotatably supports the crankshaft 23. The lower end of a connecting rod 24 is connected to the crankshaft 23 via a crank 27.

[0050] The crosshead 25 is disposed between a pair of guide plates 28 and slides up and down along each of the guide plates 28. The crosshead 25 is connected to the piston rod 22 and the connecting rod 24 via a crosshead pin 29.

[0051] The cylinder jacket 13 supports a cylinder liner 14 which is configured as an inner cylinder and which reciprocates a piston 21. More specifically, the piston 21 is disposed inside the cylinder liner 14.

[0052] The cylinder cover 15 is fixed to the upper end of the cylinder liner 14. The cylinder cover 15 and the cylinder liner 14 form a cylinder 16. The cylinder cover 15 closes the upper end of the cylinder liner 14, thereby serving as a lid for the cylinder 16.

[0053] The cylinder cover 15 is also provided with an exhaust valve 18 that is operated by a valve train (not shown). The exhaust valve 18, together with the cylinder 16, which is made up of the cylinder liner 14 and the cylinder cover 15, and the top surface of the piston 21, defines a combustion chamber 17. The exhaust valve 18 opens and closes the connection between the combustion chamber 17 and an exhaust pipe 19. The exhaust pipe 19 has an exhaust port that communicates with the combustion chamber 17, and the exhaust valve 18 is configured to open and close the exhaust port.

[0054] 3 and 4, the cylinder cover 15 is provided with one or more gas injection valves (GIVs) 40 for supplying hydrogen gas to the combustion chamber 17. The gas injection valves 40 inject hydrogen gas into the cylinder 16 by operating in accordance with the hydraulic pressure of the hydraulic oil.

[0055] In this embodiment, two gas injection valves 40 are provided for each cylinder 16, and each is oriented so as to face the interior of the combustion chamber 17. Each gas injection valve 40 has an injection port (not shown) at its tip and is configured to inject hydrogen gas from the injection port. Hereinafter, one of the two gas injection valves 40 may be referred to as the "first gas injection valve 40a" and the other as the "second gas injection valve 40b."

[0056] 6, each gas injection valve 40 is connected to a hydrogen gas flow path in the hydrogen gas supply system 4. Hydrogen gas is supplied from this flow path to each gas injection valve 40. When each gas injection valve 40 opens while hydrogen gas is being supplied, hydrogen gas is supplied into the combustion chamber 17.

[0057] Here, the supply of hydrogen gas to each gas injection valve 40 and the opening and closing of each gas injection valve 40 are performed according to the hydraulic pressure of the hydraulic oil. This hydraulic pressure is controlled by a corresponding solenoid valve (see a first injection control valve 41a, a second injection control valve 41b, and a gate control valve 41c, which will be described later). Each solenoid valve operates in accordance with a control signal input from the controller 100, thereby supplying hydrogen gas to each gas injection valve 40 and opening and closing each gas injection valve 40.

[0058] Each gas injection valve 40 supplies hydrogen gas to the combustion chamber 17, causing combustion within the combustion chamber 17. This combustion causes the piston 21 to reciprocate up and down. At this time, when the exhaust valve 18 operates to open the combustion chamber 17, the exhaust gas produced by the combustion is pushed out into the exhaust pipe 19, and fresh air is introduced into the combustion chamber 17 through a scavenging port (not shown).

[0059] Furthermore, when the piston 21 reciprocates due to combustion, the piston rod 22 reciprocates up and down together with the piston 21. This causes the crosshead 25 connected to the piston rod 22 to reciprocate up and down. The crosshead 25 allows the connecting rod 24 to rotate, and rotates the connecting rod 24 around the connection point with the crosshead 25 as a fulcrum. The crank 27 connected to the lower end of the connecting rod 24 then performs crank motion, and the crankshaft 23 rotates in response to this crank motion. The rotation of the crankshaft 23 rotates the propeller 1002 as described above, and this rotation propels the ship 1000.

[0060] (2) Hydrogen gas supply system 4 4 to 6, the hydrogen gas supply system 4 includes the two gas injection valves 40, a hydrogen gas inlet channel 42, a gas pressure accumulator chamber 44, a gas gate valve (GGV) 45, a first hydrogen gas supply channel 46, a second hydrogen gas supply channel 47, and a third hydrogen gas supply channel 48. All of these elements are provided in each of the multiple cylinders 16.

[0061] Furthermore, the gas injector 40 and the gas gate valve 45 function to supply hydrogen gas into each combustion chamber 17. At least one of the gas injector 40 and the gas gate valve 45 constitutes a "gas supply means 49" for each cylinder 16 in this embodiment. The number of gas supply means 49 is the same as the number of cylinders 16, i.e., a plurality of gas supply means 49 are provided. In this embodiment, each gas supply means 49 includes first and second gas injector valves 40a, 40b and a gas gate valve 45. The first and second gas injector valves 40a, 40b and the gas gate valve 45 are examples of "plurality of control valves" in this embodiment.

[0062] Specifically, the gas accumulator chamber 44 of each cylinder 16 is connected to the GVT 3 via a hydrogen gas pipe 6. The controller 100 opens and closes each control valve of the GVT 3, thereby controlling the supply of hydrogen gas from the hydrogen tank 2 to each gas accumulator chamber 44. By controlling the supply of hydrogen gas to each gas accumulator chamber 44, the supply of hydrogen gas to each gas injection valve 40 of each cylinder 16 is controlled.

[0063] The gas accumulator 44 accumulates the hydrogen gas supplied to each gas injection valve 40. The downstream end of the hydrogen gas pipe 6 and the upstream end of a first hydrogen gas supply passage 46 are connected to the gas accumulator 44. Of these, the downstream end of the hydrogen gas pipe 6 is connected to the gas accumulator 44 via a hydrogen gas inlet passage 42 consisting of an opening, hole, etc. The gas accumulator 44 sends the hydrogen gas supplied via the hydrogen gas pipe 6 and the hydrogen gas inlet passage 42 to the first hydrogen gas supply passage 46.

[0064] The downstream end of the first hydrogen gas supply channel 46 branches into a second hydrogen gas supply channel 47 and a third hydrogen gas supply channel 48. The second hydrogen gas supply channel 47 is connected to the first gas injection valve 40a. The third hydrogen gas supply channel 48 is connected to the second gas injection valve 40b. The first hydrogen gas supply channel 46, the second hydrogen gas supply channel 47, and the third hydrogen gas supply channel 48 connect the gas accumulator chamber 44 and the two gas injection valves 40.

[0065] The gas gate valve 45 operates in response to the hydraulic pressure of the hydraulic oil to disconnect the gas accumulator chamber 44 from the first and second gas injection valves 40a, 40b. The gas gate valve 45 is disposed midway between the gas accumulator chamber 44 and the first and second gas injection valves 40a, 40b (more specifically, in the first hydrogen gas supply passage 46), and opens and closes this section. The opening and closing of the gas gate valve 45 is controlled by the controller 100.

[0066] Here, the gas accumulator chamber 44 and hydrogen gas pipe 6 of the first cylinder 16A are referred to as the first gas accumulator chamber 44A and the first pipe 6A, respectively. The gas accumulator chamber 44 and hydrogen gas pipe 6 of the second cylinder 16B are referred to as the second gas accumulator chamber 44B and the second pipe 6B, respectively. The gas accumulator chamber 44 and hydrogen gas pipe 6 of the third cylinder 16C are referred to as the third gas accumulator chamber 44C and the third pipe 6C, respectively. The gas accumulator chamber 44 and hydrogen gas pipe 6 of the fourth cylinder 16D are referred to as the fourth gas accumulator chamber 44D and the fourth pipe 6D, respectively. The gas accumulator chamber 44 and hydrogen gas pipe 6 of the fifth cylinder 16E are referred to as the fifth gas accumulator chamber 44E and the fifth pipe 6E, respectively. The gas accumulator chamber 44 and hydrogen gas pipe 6 of the sixth cylinder 16F are referred to as the sixth gas accumulator chamber 44F and the sixth pipe 6F, respectively.

[0067] In this case, as shown in Figures 2 and 5, the GVT 3 is connected to the sixth gas accumulator chamber 44F via a sixth pipe 6F. The sixth gas accumulator chamber 44F is connected to the fifth gas accumulator chamber 44E via a fifth pipe 6E. The fifth gas accumulator chamber 44E is connected to the fourth gas accumulator chamber 44D via a fourth pipe 6D. The fourth gas accumulator chamber 44D is connected to the third gas accumulator chamber 44C via a third pipe 6C. The third gas accumulator chamber 44C is connected to the second gas accumulator chamber 44B via a second pipe 6B. The second gas accumulator chamber 44B is connected to the first gas accumulator chamber 44A via a first pipe 6A.

[0068] By configuring in this manner, the hydrogen gas supplied from GVT3 through the sixth pipe 6F is branched into a flow toward the gas injection valve 40 through the sixth gas accumulator chamber 44F and a flow toward the fifth cylinder 16E through the fifth pipe 6E.

[0069] The hydrogen gas supplied to the fifth cylinder 16E via the fifth pipe 6E branches into a flow that flows toward the gas injection valve 40 via the fifth gas accumulator chamber 44E and a flow that flows toward the fourth cylinder 16D via the fourth pipe 6D.

[0070] The hydrogen gas supplied to the fourth cylinder 16D via the fourth pipe 6D branches into a flow that flows toward the gas injection valve 40 via the fourth gas accumulator chamber 44D and a flow that flows toward the third cylinder 16C via the third pipe 6C.

[0071] The hydrogen gas supplied to the third cylinder 16C via the third pipe 6C branches into a flow that flows toward the gas injection valve 40 via the third gas accumulator chamber 44C and a flow that flows toward the second cylinder 16B via the second pipe 6B.

[0072] The hydrogen gas supplied to the second cylinder 16B via the second pipe 6B branches into a flow that flows toward the gas injection valve 40 via the second gas accumulator chamber 44B and a flow that flows toward the second cylinder 16A via the first pipe 6A.

[0073] Therefore, the hydrogen gas supplied from GVT3 flows through each cylinder 16 in the following order from the front in the longitudinal direction: sixth cylinder 16F, fifth cylinder 16E, fourth cylinder 16D, third cylinder 16C, second cylinder 16B, and first cylinder 16A.

[0074] As described above, the hydrogen gas inlet passage 42, the gas accumulator chamber 44, the first hydrogen gas supply passage 46, the second hydrogen gas supply passage 47, the third hydrogen gas supply passage 48, and the hydrogen gas pipe 6 are all connected to the combustion chambers 17 of the multiple cylinders 16, and are configured to allow the flow of hydrogen gas supplied to each cylinder 16. These elements constitute the "hydrogen gas flow passage" in this embodiment.

[0075] Furthermore, among the elements that make up the hydrogen gas flow passage, the hydrogen gas inlet passage 42, the gas accumulator chamber 44, the first hydrogen gas supply passage 46, the second hydrogen gas supply passage 47, and the third hydrogen gas supply passage 48 are connected to each combustion chamber 17 of the multiple cylinders 16, and are provided in the same number as the multiple cylinders 16. These elements make up the "hydrogen gas branch passages" in this embodiment.

[0076] In addition, the hydrogen gas pipe 6 that constitutes the hydrogen gas flow passage is shared among multiple cylinders 16 and is arranged outside the multiple cylinders 16. The hydrogen gas pipe 6 constitutes a "shared hydrogen gas path" in this embodiment.

[0077] 4, each element constituting the hydrogen gas branch passage is formed for each cylinder 16 inside the cylinder cover 15 that constitutes that cylinder 16. It is not essential to form some or all of the hydrogen gas branch passage inside the cylinder cover 15. For example, the gas accumulator chamber 44 and some of the hydrogen gas flow passages connected to the gas accumulator chamber 44 may be formed separately from the cylinder cover 15 and disposed outside the cylinder cover 15.

[0078] 4, the gas injection valve 40 and the gas gate valve 45 constituting the gas supply means 49 are both inserted into components of the cylinder 16 (cylinder cover 15 in the illustrated example). Of the elements constituting the gas supply means 49, it is not essential that the gas gate valve 45 be inserted into the cylinder cover 15. As described above, the gas gate valve 45 may also be disposed outside the cylinder cover 15, similar to the gas accumulator chamber 44 and the like.

[0079] 4, the gas supply means 49 in this embodiment has a double seal structure with two seal rings. For example, the gas injector 40 is sealed by a first seal ring 31 and a second seal ring 32 arranged in the axial direction of the gas injector 40. The first and second seal rings 31 and 32 seal between the outer circumferential surface of the gas injector 40 and the inner circumferential surface of the insertion hole in the cylinder cover 15, into which the gas injector 40 is inserted. A leakage gas passage 51, which will be described later, and in particular its downstream flow path 8, communicate with a gap between the outer circumferential surface of the gas injector 40 and the inner circumferential surface of the insertion hole, particularly a gap located between the first and second seal rings 31 and 32.

[0080] Similarly, the gas gate valve 45 is sealed by a third seal ring 33 and a fourth seal ring 34 that are aligned in the axial direction of the gas gate valve 45. The third and fourth seal rings 33, 34 seal between the outer circumferential surface of the gas gate valve 45 and the inner circumferential surface of an insertion hole in the cylinder cover 15, into which the gas gate valve 45 is inserted. A leakage gas flow passage 51, which will be described later, and in particular its downstream flow passage 8, communicate with a gap between the outer circumferential surface of the gas gate valve 45 and the inner circumferential surface of the insertion hole, in particular a gap located between the third and fourth seal rings 33, 34.

[0081] In this case, even if the first seal ring 31, which is close to the combustion chamber 17, of the first and second seal rings 31, 32, is damaged, or even if the third seal ring 33, which is close to the pressure accumulator chamber 44, of the third and fourth seal rings 33, 34, is damaged, the second or fourth seal ring 32, 34 can prevent hydrogen gas from leaking outside the engine 1.

[0082] However, since the first or third seal ring 31, 33 is damaged, a mechanism is required to exhaust the hydrogen gas that has entered the gap between the gas injection valve 40 or gas gate valve 45 and the cylinder cover 15 as quickly as possible.

[0083] In order to meet such needs, the engine 1 is configured to be equipped with a leaked gas circulation system 5, which will be described in detail below, in addition to the hydrogen gas supply system 4.

[0084] (3) Leaked gas distribution system 5 As shown in FIGS. 5 and 6, the leaked gas flow system 5 includes a leaked gas flow passage 51, a plurality of leak sensors 52, a plurality of switching valves 53, and a flow generator .

[0085] The leaked gas flow passage 51 is connected to each gas supply means 49 of the multiple cylinders 16, and is a flow passage through which hydrogen gas leaked from each gas supply means 49 flows. In particular, in this embodiment, the leaked gas flow passage 51 is configured to allow gases other than hydrogen gas to flow through.

[0086] The "other gas" referred to here may be air (atmosphere) taken in from outside the engine 1, or an inert gas (inert gas). In this embodiment, the inert gas includes a gas that does not contain oxygen, and more specifically, includes nitrogen gas.

[0087] More specifically, the leaked gas passage 51 is configured to allow hydrogen gas (hereinafter also referred to as "leaked gas") that has entered into a gap when a tear or the like occurs in the first or third seal ring 31, 33 that seals the gap between the gas gate valve 45, the first gas injection valve 40a, and the second gas injection valve 40b, which serve as the gas supply means 49, and the cylinder cover 15. In this embodiment, for example, the flow generator 54 is used to create a negative pressure in the leaked gas passage 51, thereby allowing the leaked gas to flow into the leaked gas passage 51.

[0088] More specifically, as illustrated in Figure 6, the leakage gas flow passage 51 is composed of an upstream flow path 7 arranged upstream of each gas supply means 49 in the air flow direction, a plurality of downstream flow paths 8 arranged downstream of each gas supply means and provided for each cylinder 16, and a shared leakage gas path 9 arranged downstream of each gas supply means and shared between the cylinders 16.

[0089] 5 and 6, the upstream flow path 7 has a first external common pipe 71 and a plurality (six in this embodiment) of first external branch pipes 72. The upstream flow path 7 is disposed outside the engine 1 (for example, in the internal space of the engine compartment 1003).

[0090] In this embodiment, the first external shared pipe 71 has an upstream end that is open to the atmosphere. The first external shared pipe 71 is shared among multiple cylinders 16. Instead of opening the upstream end of the first external shared pipe 71 to the atmosphere, the downstream end of a leakage gas shared passage 9, which will be described later, may be open to the atmosphere. In this case, a flow generator 54 configured to create a positive pressure inside the leakage gas flow passage 51 is connected to the upstream end of the first external shared pipe 71.

[0091] The multiple first external branch pipes 72 each branch off from the first external shared pipe 71. Each first external branch pipe 72 is connected to the gas supply means 49 of a different cylinder 16. Each first external branch pipe 72 further branches off into two pipes for each cylinder 16, and each pipe is connected to the first gas injection valve 40a and the second gas injection valve 40b of each cylinder 16, respectively.

[0092] The downstream flow paths 8 branch off for each cylinder 16 so as to be connected to the gas supply means 49 of each cylinder 16. The downstream flow paths 8 are examples of "leakage gas branch paths" in this embodiment. As shown in FIG. 6 , each downstream flow path 8 has a first discharge path 81, a second discharge path 82, a third discharge path 83, and a fourth discharge path 84.

[0093] The first discharge passage 81 is a flow path extending from the first gas injection valve 40a. The first discharge passage 81 receives leakage gas (hydrogen gas) leaking from a gap between the first gas injection valve 40a and the cylinder cover 15.

[0094] The second discharge passage 82 is a flow path extending from the second gas injection valve 40b. The leaked gas leaking from the gap between the second gas injection valve 40b and the cylinder cover 15 flows into the second discharge passage 82.

[0095] The third discharge path 83 is a flow path formed by the junction of the first discharge path 81 and the second discharge path 82. The upstream end of the third discharge path 83 is connected to the junction of the first discharge path 81 and the second discharge path 82. The downstream end of the third discharge path 83 is connected to the upstream end of one leakage gas shared path 9. The downstream end of another leakage gas shared path 9 is also connected to the vicinity of the downstream end of the third discharge path 83.

[0096] The fourth discharge path 84 is a flow path extending from the gas gate valve 45. Leaked gas (hydrogen gas) leaking from a gap between the gas gate valve 45 and the cylinder cover 15 flows into the fourth discharge path 84. The downstream end of the fourth discharge path 84 is connected to a midpoint of the third discharge path 83. For example, in this embodiment, the downstream end of the fourth discharge path 84 is connected to a portion of the third discharge path 83 that is upstream of the connection point with the shared leaked gas path 9.

[0097] The shared leakage gas passage 9 is shared among multiple cylinders 16 and is arranged outside the multiple cylinders 16 (for example, the internal space of the engine room 1003). In particular, in this embodiment, the shared leakage gas passage 9 is configured by multiple leakage gas pipes 91 connecting adjacent cylinders 16.

[0098] 7, the hydrogen gas pipe 6 serving as the shared hydrogen gas path is disposed inside the leaking gas pipe 91 that forms the shared leaking gas path 9. In other words, the hydrogen gas pipe 6 is covered by the corresponding leaking gas pipe 91. If a problem such as breakage occurs in the hydrogen gas pipe 6, the leaking gas that has leaked from the hydrogen gas pipe 6 will be sucked into the leaking gas pipe 91.

[0099] For example, among the multiple leakage gas pipes 91, the leakage gas pipe 91 connecting the sixth cylinder 16F and the fifth cylinder 16E has an upstream end connected to the third discharge passage 83 of the fifth cylinder 16E and a downstream end connected to the third discharge passage 83 of the sixth cylinder 16E. This leakage gas pipe 91 covers the fifth pipe 6E.

[0100] Similarly, a leakage gas pipe 91 connecting the fifth cylinder 16E and the fourth cylinder 16D has an upstream end connected to the third discharge passage 83 of the fourth cylinder 16D and a downstream end connected to the third discharge passage 83 of the fifth cylinder 16E. This leakage gas pipe 91 covers the fourth pipe 6D.

[0101] The same applies to the leakage gas pipe 91 connecting the fourth cylinder 16D and the third cylinder 16C, and the leakage gas pipe 91 connecting the third cylinder 16C and the second cylinder 16B.

[0102] Furthermore, a leakage gas pipe 91, having an upstream end connected to the third discharge passage 83 of the sixth cylinder 16F, covers the sixth pipe 6F. A flow generator 54 is connected to the downstream end of this leakage gas pipe 91. The flow generator 54 operates to suck out the other gases (e.g., air) from the leakage gas common passage 9 based on a control signal output from the controller 100. As a result, the leakage gas common passage 9, and in turn the leakage gas flow passage 51, are set to a negative pressure below atmospheric pressure.

[0103] It is not essential to create a negative pressure in the leaked gas shared passage 9, and therefore in the leaked gas flow passage 51. The flow generator 54 may be operated to push in the other gases (e.g., air) described above, thereby setting the leaked gas shared passage 9, and therefore in the leaked gas flow passage 51, to a positive pressure equal to or higher than atmospheric pressure.

[0104] By connecting the flow generator 54 to the leaked gas pipe 91 of the sixth cylinder 16F, the air supplied from the first external shared pipe 71 flows through the leaked gas circulation systems 5 corresponding to each cylinder 16 in the order of the first cylinder 16A, the second cylinder 16B, the third cylinder 16C, the fourth cylinder 16D, the fifth cylinder 16B and the sixth cylinder 16F from the rear in the fore-and-aft direction. When attention is paid to the flow direction of the air and leaked gas between the cylinders 16, the flow direction of the air and leaked gas in the leaked gas circulation system 5 is opposite to the flow direction of hydrogen gas in the hydrogen gas supply system 4.

[0105] The plurality of leakage sensors 52 are provided in numbers at least equal to the number of the plurality of cylinders 16, and each outputs a signal indicating the presence or absence of hydrogen gas leakage in the plurality of gas supply means 49.

[0106] Specifically, in this embodiment, the number of leak sensors 52 provided is the same as the number of cylinders 16 (i.e., six). As shown in FIGS. 4 to 6, each leak sensor 52 is connected to a leaking gas flow passage 51. Each leak sensor 52 detects the concentration of hydrogen gas in the leaking gas flow passage 51. Each leak sensor 52 is electrically connected to the controller 100, and inputs each detection signal to the controller 100. The number of leak sensors 52 may be greater than the number of cylinders 16.

[0107] Specifically, the multiple leakage sensors 52 are arranged in the downstream flow paths 8 corresponding to each of the multiple cylinders 16 among the multiple downstream flow paths 8. For example, if N is a natural number, and the number of leakage sensors 52 and the number of cylinders 16 are each "N," the Nth leakage sensor 52 will be arranged in the downstream flow path 8 connected to the Nth cylinder 16. On the other hand, if M (>N) is a natural number, the number of leakage sensors 52 is "M," and the number of cylinders 16 is "N," two or more leakage sensors 52 will be arranged in the downstream flow paths 8 corresponding to one or more cylinders 16.

[0108] More specifically, the plurality of leakage sensors 52 are each disposed in the third discharge passage 83 of the corresponding cylinder 16. Each leakage sensor 52 is disposed in the third discharge passage 83 downstream of the connection with the fourth discharge passage 84 and upstream of the connection with the shared leakage gas passage 9.

[0109] As shown in a modified example described later, at least one of the plurality of leakage sensors 52 may be disposed in the shared leakage gas passage 9.

[0110] The multiple switching valves 53 are each disposed in a corresponding cylinder 16. More specifically, each switching valve 53 is disposed in the third discharge path 83 of the corresponding cylinder 16. Each switching valve 53 is disposed in the third discharge path 83 downstream of the attachment position of the leakage sensor 52 and upstream of the connection with the shared leakage gas path 9. Each switching valve 53 is electrically connected to the controller 100, and opens and closes upon receiving a control signal from the controller 100.

[0111] (4) Controller 100 Fig. 8 is a block diagram showing the configuration of the controller 100. The controller 100 has a processor, a volatile memory, a non-volatile memory, and an input / output device. The controller 100 is connected to various sensors including a plurality of leak sensors 52, and a telegraph 101. The controller 100 is also connected to at least a plurality of gas supply means 49. Although Fig. 8 shows only one gas supply means 49, in this embodiment, the same number of gas supply means 49 as the number of cylinders 16 are provided.

[0112] The controller 100 generates a control signal based on signals input from sensors, for example, when the telegraph 101 is operated. The controller 100 inputs the generated control signals to a plurality of solenoid valves, and controls the GVT 3, the gas injection valve 40, the gas gate valve 45, etc. via those solenoid valves.

[0113] For example, the controller 100 is connected to the first gas injector 40a via a first injection control valve 41a. The first injection control valve 41a is an electromagnetic valve that controls the supply of hydraulic oil to the first gas injector 40a.

[0114] The controller 100 is also connected to the second gas injection valve 40b via the second injection control valve 41b. The second injection control valve 41b is an electromagnetic valve that controls the supply of hydraulic oil to the second gas injection valve 40b.

[0115] The controller 100 is also connected to the gas gate valve 45 via a gate control valve 41c. The gate control valve 41c is an electromagnetic valve that controls the supply of hydraulic oil to the gas gate valve 45.

[0116] For example, the controller 100 controls the GVT 3 and opens the gas gate valve 45, so that hydrogen gas is supplied from the GVT 3 to each gas injection valve 40. This supply can be controlled individually for each cylinder 16.

[0117] The controller 100 then opens the two gas injection valves 40, causing hydrogen gas to be injected into the combustion chamber 17 from the injection port of each gas injection valve 40. This injection can also be controlled individually for each cylinder 16.

[0118] In this way, the controller 100 can inject hydrogen gas into each cylinder 16, thereby burning the hydrogen gas in the corresponding combustion chamber 17. The engine 1 operates when the hydrogen gas is burned in the combustion chamber 17. The controller 100 can control the operation of the engine 1 on a cylinder-by-cylinder 16 basis via the multiple gas supply means 49.

[0119] Furthermore, the controller 100 according to this embodiment is configured to execute processing to respond to hydrogen gas leakage by using a plurality of leakage sensors 52 and a plurality of gas supply means 49. Hereinafter, this processing will be referred to as "leak response processing," and its details will be described.

[0120] <Leak response process details> For simplicity of explanation, one or more of the multiple gas supply means 49 in which a hydrogen gas leak has occurred will be referred to as a "specific supply means." Furthermore, one or more of the multiple cylinders 16 corresponding to a specific supply means will be referred to as a "specific cylinder." As indicated by this definition, the number of specific supply means and specific cylinders is not always one. For example, if leakage occurs simultaneously in the gas supply means 49 for the first cylinder 16A and the gas supply means 49 for the second cylinder 16B, there will be two specific supply means and two specific cylinders.

[0121] Fig. 9 is a flowchart illustrating the leakage response process. Each process shown in Fig. 9 is repeatedly performed while the engine 1 is operating, that is, while hydrogen gas is being burned.

[0122] First, in step S1, the controller 100 reads the detection signal from each of the plurality of leak sensors 52. In the following step S2, the controller 100 determines whether or not a hydrogen gas leak is occurring based on the detection signal output from at least one of the plurality of leak sensors 52.

[0123] As described above, when the hydrogen gas concentration is detected by each leak sensor 52, the controller 100 determines that a leak has occurred when there is an increase in the detected concentration (the concentration of hydrogen gas corresponding to the detection signal, i.e., the hydrogen gas concentration in the air), but may also determine that no leak has occurred unless there is an increase in the detected concentration.

[0124] Here, the controller 100 may determine that an "increase in the detected concentration has occurred" if the detected concentration becomes a non-zero value (i.e., if hydrogen gas has been mixed into the air), and may determine that an "increase in the detected concentration has not occurred" if the detected concentration remains at zero.

[0125] If the determination in step S2 is NO, the controller 100 determines that no hydrogen gas leakage has occurred and ends the processing in Fig. 9. In this case, the controller 100 starts the processing in Fig. 9 again from step S1.

[0126] On the other hand, if the determination in step S2 is YES, the controller 100 determines that hydrogen gas is leaking from some part of the engine 1, and proceeds to step S3.

[0127] In step S3, the controller 100 estimates a specific cylinder from among the multiple cylinders 16 based on a detection signal output from at least one of the multiple leakage sensors 52. As will be described below, this estimation method can be rephrased as a process of estimating a specific cylinder based on the detection position of each leakage sensor 52.

[0128] Specifically, the controller 100 receives detection signals from each of the plurality of leakage sensors 52, and estimates the specific cylinder based on a combination of detection values ​​(detected concentrations) corresponding to the respective detection signals.

[0129] More specifically, when each leak sensor 52 is arranged in the third discharge passage 83 of each cylinder 16, as in the examples of Figures 5 and 6, the leak sensor 52 arranged in the third discharge passage 83 of a particular cylinder outputs a detection signal indicating that a hydrogen gas leak is occurring, such as when the detected concentration increases to a non-zero value.

[0130] On the other hand, considering that the third discharge path 83 is not shared among the cylinders 16, it is considered that the detected concentration of the leakage sensors 52 arranged in the third discharge paths 83 of other cylinders 16 will not increase even if a specific cylinder exists. If an increase in the detected concentration is confirmed in multiple cylinders 16, it is considered that multiple specific cylinders exist. By combining the detected concentrations of the leakage sensors 52 corresponding to each cylinder 16, it is possible to estimate the specific cylinder from among the multiple cylinders 16.

[0131] In this way, when the controller 100 of this embodiment receives a detection signal from one or more of the multiple leak sensors 52 indicating that hydrogen gas is leaking, it estimates that the cylinder 16 among the multiple cylinders 16 that is connected to the downstream flow path 8 in which the leak sensor 52 that output the detection signal is located is the specific cylinder.

[0132] The controller 100 closes the two switching valves 53 in the cylinder 16 that is estimated to be the specific cylinder.

[0133] When the process proceeds to step S4 (when a hydrogen gas leak has occurred), the controller 100 continues to operate the engine 1 while reducing the amount of hydrogen gas supplied to the specific cylinder via the multiple gas supply means 49. In this case, the controller 100 reduces the amount of hydrogen gas supplied to the specific cylinder by reducing the injection pressure of the hydrogen gas.

[0134] Specifically, the controller 100 reduces the amount of hydrogen gas supplied to specific cylinders among the multiple cylinders 16, while maintaining the amount of hydrogen gas supplied to the other cylinders 16, thereby continuing operation of the engine 1. Note that the controller 100 may increase the amount of hydrogen gas supplied to the other cylinders 16 in order to maintain the amount of hydrogen gas burned in the entire multiple cylinders 16 as much as possible.

[0135] Furthermore, instead of reducing the amount of hydrogen gas supplied to a specific cylinder, the controller 100 may set the amount of hydrogen gas supplied to the specific cylinder to zero. This process can also be described as "stopping the supply of hydrogen gas to the specific cylinder." When this process is adopted, the controller 100 performs reduced-cylinder operation, skipping the combustion of hydrogen gas in the specific cylinder. By performing reduced-cylinder operation, it becomes possible to perform maintenance on the specific cylinder more safely.

[0136] As described above, the engine 1 may be an engine that can switch between a mode in which hydrogen gas is burned alone and a mode in which hydrogen gas and oil fuel are burned together. In this case, the controller 100 may continue to operate the engine 1 by supplying oil fuel instead of hydrogen gas to at least certain cylinders among the plurality of cylinders 16.

[0137] <First modified engine model> In the above embodiment, the multiple leakage sensors 52 are respectively arranged in the third discharge passages 83 of the cylinders 16, but the present disclosure is not limited to such a layout. At least one of the multiple leakage sensors 52 may be arranged in the shared leakage gas passage 9.

[0138] Fig. 10 is a diagram corresponding to Fig. 5 illustrating a hydrogen engine (hereinafter also simply referred to as "engine") 1' according to a first modified example. Fig. 11 is a diagram corresponding to Fig. 9 illustrating a leakage response process according to the first modified example.

[0139] As shown in Figure 10, in the engine 1' according to the first modified example, the multiple leakage sensors 52' are all arranged in the shared leakage gas path 9. In the illustrated example, the sixth leakage sensor 52' ​​is arranged in the leakage gas pipe 91 connecting the flow generator 54 and the sixth cylinder 16F. Furthermore, if N is a natural number greater than or equal to 1, the Nth leakage sensor 52' ​​is arranged in the leakage gas pipe 91 connecting the (N+1)th cylinder 16 and the Nth cylinder 16.

[0140] In this case, even if a hydrogen gas leak is detected by the Nth leak sensor 52', it is not easy to determine whether the leak was detected in the (N-1)th cylinder 16 or the Nth cylinder 16.

[0141] In response to this, the inventors of the present application have focused on the fact that the shared leak gas passage 9 is connected to all of the cylinders 16, and have devised another example of a leak response process. This example is shown in FIG. 11. The process of FIG. 11 is executed by the controller 100 while the engine 1′ is operating. The process of FIG. 11 is the same as the leak response process illustrated in FIG. 9 in that "the controller 100 determines whether or not a hydrogen gas leak is occurring and identifies a specific cylinder among the multiple cylinders 16 based on a detection signal output from at least one of the multiple leak sensors 52′, and if a hydrogen gas leak is occurring, reduces or eliminates the amount of hydrogen gas supplied to the specific cylinder via the multiple gas supply means 49 while continuing to operate the engine 1′."

[0142] Specifically, in step S101, the controller 100 reads the detection signal from each of the plurality of leak sensors 52′. In the following step S102, the controller 100 determines whether or not a hydrogen gas leak is occurring based on the detection signal output from at least one of the plurality of leak sensors 52.

[0143] As described above, the controller 100 may determine that a hydrogen gas leak has occurred when an increase in the detected concentration is detected, but may also determine that no leakage has occurred unless an increase in the detected concentration is detected. The meaning of "an increase in the detected concentration" is the same as in the example of FIG. 9.

[0144] If the determination in step S102 is NO, the controller 100 determines that no hydrogen gas leakage has occurred and ends the processing in Figure 11. In this case, the controller 100 starts the processing in Figure 11 again from step S101.

[0145] On the other hand, if the determination in step S102 is YES, the controller 100 determines that hydrogen gas is leaking from some part of the engine 1', and proceeds to step S103.

[0146] In step S103, the controller 100 estimates a specific cylinder from among the multiple cylinders 16 based on a detection signal output from at least one of the multiple leakage sensors 52′. As will be described below, the estimation method according to the modified example can be rephrased as a process of estimating a specific cylinder based on the order of detection timings (detection values) of the leakage sensors 52.

[0147] More specifically, the controller 100 receives detection signals from each of the plurality of leakage sensors 52' and estimates the specific cylinder based on a combination of the detection timings of the detection signals.

[0148] More specifically, if a leakage sensor 52' ​​is placed on each leakage gas pipe 91, as in the example of Figure 10, there is a possibility that hydrogen gas is leaking from both of the two cylinders 16 connected by that leakage gas pipe 91.

[0149] Therefore, the controller 100 identifies the leak sensor 52' ​​among the multiple leak sensors 52' that first output a signal indicating an increase in the detected concentration and the leak sensor 52' ​​that second output a signal indicating an increase in the detected concentration, and estimates the specific cylinder based on the combination of these leak sensors 52.

[0150] For example, consider a case where the first to Nth leakage sensors 52' are defined as described above. In this case, suppose that the first leakage sensor 52' ​​outputs a signal first, and then the second leakage sensor 52' ​​outputs a signal. In this case, the controller 100 infers that the "specific cylinder = first cylinder."

[0151] Similarly, the controller 100 determines that the second leakage sensor 52' ​​first outputs a signal, and then the third leakage sensor 52' ​​outputs a signal. In this case, the controller 100 also estimates that the "specific cylinder = 2 cylinders."

[0152] These estimates focus on the flow direction of the leaking gas in the leaking gas flow passage 51.

[0153] Similarly, the controller 100 can receive detection signals from each of the plurality of leakage sensors 52' and estimate a specific cylinder based on a combination of each detection value (detected concentration).

[0154] When configured in this manner, the controller 100 identifies the leak sensor 52' ​​with the highest detected concentration and the leak sensor 52' ​​with the second highest detected concentration among the multiple leak sensors 52', and estimates the specific cylinder based on the combination of these leak sensors 52'.

[0155] For example, consider a case where the first to Nth leakage sensors 52' are defined as described above. In this case, assume that the detected concentration at the first leakage sensor 52' ​​is the highest and the detected concentration at the second leakage sensor 52' ​​is the second highest. In this case, the controller 100 infers that the "specific cylinder = first cylinder." The same applies when the magnitude relationship between the detected concentrations is reversed.

[0156] The process in the following step S104 is substantially the same as the process in step S4 in FIG.

[0157] In this way, the controller 100 according to the first modification can estimate the specific cylinder based on the detection timing or the order of the detection values ​​corresponding to each detection signal.

[0158] It is also possible to arrange a leakage sensor 52 in the third discharge passage 83 of each cylinder 16 as in Fig. 5, and then arrange a leakage sensor 52 in each leakage gas pipe 91 as in Fig. 10. In other words, the configuration illustrated in Fig. 5 and the configuration illustrated in Fig. 10 may be combined. In that case, the leakage response process may also be a combination of the process shown in Fig. 9 and the process shown in Fig. 11.

[0159] <Second modified engine> In the above embodiment, the shared leakage gas passage 9 is configured to be shared among all of the cylinders 16, but the present disclosure is not limited to such a configuration. As in the hydrogen engine 1″ according to the second modified example shown in FIG. 12 , the shared leakage gas passage 9 may be configured to be separated between some of the multiple cylinders 16 and the other portions.

[0160] <Significance of the above embodiment and first and second modifications> As described above, by using at least the same number of leak sensors 52, 52' as the number of cylinders 16, it is possible to estimate which cylinder 16 is the specific cylinder from among the multiple cylinders 16. This makes it possible to properly identify the location where a hydrogen gas leak has occurred, even in hydrogen engines that can be relatively large, such as marine hydrogen engines 1, 1'. This allows appropriate countermeasures to be taken against the hydrogen gas leak.

[0161] By configuring the system to reduce or eliminate the amount of hydrogen gas supplied to specific cylinders rather than reducing or eliminating the amount of hydrogen gas supplied to all cylinders 16, it becomes possible to continue operating the engines 1, 1' using the other cylinders 16. This makes it possible to prevent the ship 1000 from falling into a dead ship state.

[0162] As described above, according to the embodiment, safety is ensured when using hydrogen gas, and even if a hydrogen gas leak occurs, the ship 1000 can be prevented from falling into a dead ship state.

[0163] 10, in a configuration including a shared leakage gas path 9, a hydrogen gas leak occurring in any of the cylinders 16 may be detected by multiple leakage sensors 52 through the shared leakage gas path 9. However, even if the leak is detected by multiple leakage sensors 52, it is thought that there will be a discrepancy in the detection order or detection values ​​of each leakage sensor 52 due to the flow of hydrogen gas through the shared leakage gas path 9.

[0164] 11, the controller 100 identifies the specific cylinder by utilizing the aforementioned deviation. With this configuration, even if at least some of the leakage sensors 52 are arranged in the shared leakage gas passage 9, it becomes possible to appropriately estimate the specific cylinder.

[0165] 5 and 6, if a leakage sensor 52 is arranged in each leakage gas branch path (downstream flow path 8), hydrogen gas leakage occurring in any of the cylinders 16 will be detected by the leakage sensor 52 arranged in the downstream flow path 8 corresponding to that cylinder 16. In other words, since there is a one-to-one correspondence between each leakage sensor 52 and each cylinder 16, it is possible to appropriately estimate the specific cylinder by utilizing this correspondence.

[0166] 5 and other figures, by circulating air through the leaking gas passage 51, when a hydrogen gas leak occurs, the hydrogen gas that has flowed into the leaking gas passage 51 can be drawn into the air flow (gas flow) in the leaking gas passage 51 or swept away by the air flow, making it possible to more appropriately deal with the hydrogen gas leak.

[0167] 5 and other figures, by using the flow generator 54 to set the air pressure inside the leaking gas passage 51 to a negative pressure, when hydrogen gas leaks, the hydrogen gas can be sucked into the leaking gas passage 51. This makes it possible to deal with hydrogen gas leaks more appropriately.

[0168] 7, by disposing the hydrogen gas pipe 6 inside the leaking gas pipe 91, when hydrogen gas leaks in the hydrogen gas pipe 6 serving as a shared hydrogen gas passage, the hydrogen gas can be sent to the leaking gas pipe 91. This makes it possible to deal with hydrogen gas leaks more appropriately.

[0169] 10 and 12, the operation of the engines 1, 1' can be continued by reducing or eliminating the supply of hydrogen gas to a specific cylinder while continuing to supply hydrogen gas to the other cylinders 16. This makes it possible to prevent the ship 1000 from falling into a dead ship state.

[0170] Furthermore, as described in the explanation of the above embodiment, the specific cylinder may be configured to be supplied with oil fuel instead of hydrogen gas, and by configuring it in this way, it becomes possible to continue operating the specific cylinder while preventing leakage of hydrogen gas.

[0171] 4, the gas accumulator chamber 44 is provided in the cylinder cover 15 of each cylinder 16, but the present disclosure is not limited to such a configuration. The gas accumulator chamber 44 may be formed in a box body as a separate component attached to a component of the cylinder 16 (e.g., the cylinder cover 15). In this case, the gas gate valve 45 constituting the "plurality of control valves" is inserted into the box body, and the leakage gas branch path 8 communicates with the gap between the outer peripheral surface of the gas gate valve 45 and the inner peripheral surface of the box body. [Explanation of symbols]

[0172] S Engine System 1,1',1" Hydrogen Engine 15 Cylinder cover (component) 16 cylinders 17 Combustion chamber 23 Crankshaft 4 Hydrogen gas distribution system 42 Hydrogen gas inlet channel (hydrogen gas flow channel, hydrogen gas branch channel) 44 Gas accumulator (hydrogen gas flow passage, hydrogen gas branch passage) 46 First hydrogen gas supply channel (hydrogen gas flow channel, hydrogen gas branch channel) 47 Second hydrogen gas supply channel (hydrogen gas flow channel, hydrogen gas branch channel) 48 Third hydrogen gas supply channel (hydrogen gas flow channel, hydrogen gas branch channel) 6 Hydrogen gas pipe (hydrogen gas flow passage, hydrogen gas shared passage) 49 Gas supply means 40 Gas injection valve (gas supply means, control valve) 45 Gas gate valve (gas supply means, control valve) 5. Gas leakage distribution systems, etc. 51 Leakage gas flow path 7 Upstream flow path (leakage gas flow path) 8 Downstream flow path (leakage gas flow path, leakage gas branch path) 9. Leakage gas shared passage (leakage gas flow passage) 91 Leaking gas pipe 52,52' Leak Sensor 100 Controllers 1000 ships

Claims

1. A hydrogen engine for a ship, comprising a plurality of cylinders connected via a common crankshaft, and combusting hydrogen gas in each combustion chamber of the plurality of cylinders, a plurality of gas supply means provided in each of the plurality of cylinders for supplying hydrogen gas into each of the combustion chambers; a plurality of leakage sensors provided in the same number as the plurality of cylinders, each of which outputs a signal indicating whether or not there is a hydrogen gas leakage in the plurality of gas supply means; a controller connected to the plurality of gas supply means and the plurality of leak sensors and for controlling operation of the hydrogen engine; Among the plurality of gas supply means, one or more gas supply means in which hydrogen gas leakage has occurred will be referred to as a specific supply means, and among the plurality of cylinders, one or more cylinders corresponding to the specific supply means will be referred to as a specific cylinder. The controller, during operation of the hydrogen engine, determining whether or not a hydrogen gas leak is occurring based on a detection signal output from at least one of the plurality of leak sensors, and estimating the specific cylinder among the plurality of cylinders; If a hydrogen gas leak occurs, the amount of hydrogen gas supplied to the specific cylinder via the plurality of gas supply means is reduced or set to zero, while the operation of the hydrogen engine is continued. A hydrogen engine characterized by:

2. 2. The hydrogen engine according to claim 1, a leakage gas flow passage connected to each gas supply means of the plurality of cylinders and allowing hydrogen gas leaking from each gas supply means to flow; the plurality of leakage sensors detect a concentration of hydrogen gas in the leakage gas flow passage; The controller receives detection signals from each of the plurality of leakage sensors, and estimates the specific cylinder based on one or more combinations of detection timings or detection values ​​of the detection signals corresponding to each of the plurality of leakage sensors. A hydrogen engine characterized by:

3. 3. The hydrogen engine according to claim 2, the leakage gas flow passage is configured to include a shared leakage gas passage shared among the plurality of cylinders, At least one of the plurality of leak sensors is disposed in the shared leak gas path; The controller estimates the specific cylinder based on the order of detection of the detection signals or the order of high and low detection values. A hydrogen engine characterized by:

4. 3. The hydrogen engine according to claim 2, the leakage gas flow passage is configured to include a plurality of leakage gas branch paths branched for each cylinder so as to be connected to the gas supply means of each of the plurality of cylinders, the plurality of leakage sensors are arranged in the plurality of leakage gas branch paths corresponding to the plurality of cylinders, When the controller receives a detection signal indicating that hydrogen gas is leaking from one or more of the plurality of leak sensors, it estimates that the cylinder among the plurality of cylinders that is connected to the leak gas branch path in which the leak sensor that output the detection signal is located is the specific cylinder. A hydrogen engine characterized by:

5. 5. The hydrogen engine according to claim 4, a hydrogen gas flow passage connected to each combustion chamber of the plurality of cylinders, through which hydrogen gas to be supplied to each cylinder flows; the hydrogen gas flow passage is configured to include a plurality of hydrogen gas branch passages connected to the respective combustion chambers of the plurality of cylinders, the plurality of gas supply means are respectively constituted by a plurality of control valves that open and close hydrogen gas flow passages provided in the plurality of cylinders, each of the plurality of control valves is inserted into a component of the cylinder or a separate part attached to the component; The plurality of leakage gas branch paths are respectively connected to gaps between outer circumferential surfaces of the plurality of control valves and inner circumferential surfaces of the component parts or the separate parts. A hydrogen engine characterized by:

6. 3. The hydrogen engine according to claim 2, The leaking gas flow passage is configured to allow gases other than hydrogen gas to flow through it. A hydrogen engine characterized by:

7. 3. The hydrogen engine according to claim 2, a hydrogen gas flow passage connected to each combustion chamber of the plurality of cylinders, through which hydrogen gas to be supplied to each cylinder flows; the leakage gas flow passage is shared among the plurality of cylinders and is configured to include a shared leakage gas passage arranged outside the plurality of cylinders, The hydrogen gas flow passage is a plurality of hydrogen gas branches connected to the respective combustion chambers of the plurality of cylinders; a hydrogen gas shared passage shared among the plurality of cylinders and disposed outside the plurality of cylinders; The hydrogen gas sharing passage is disposed within the piping that forms the leaking gas sharing passage. A hydrogen engine characterized by:

8. 2. The hydrogen engine according to claim 1, When a hydrogen gas leak occurs, the controller reduces or eliminates the amount of hydrogen gas supplied to the specific cylinder among the plurality of cylinders, while maintaining or increasing the amount of hydrogen gas supplied to the cylinders other than the specific cylinder, thereby continuing operation of the hydrogen engine. A hydrogen engine characterized by:

9. 9. The hydrogen engine according to claim 8, The hydrogen engine is switchable between a mode in which hydrogen gas is burned alone and a mode in which hydrogen gas and oil fuel are burned in combination, When a hydrogen gas leak occurs, the controller continues operation of the hydrogen engine by supplying oil fuel instead of hydrogen gas to at least the specific cylinder among the plurality of cylinders. A hydrogen engine characterized by:

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