Piping structure

Abstract

(Task) To provide a piping structure that can reduce the piping space required for alternative fuel injection valves. (Solution) A piping structure in one aspect of the present invention comprises a plurality of pipes including an alternative fuel pipe that is joined to a fuel injection valve formed on the upper part of a cylinder of a marine internal combustion engine and supplies alternative fuel injected from the fuel injection valve into a combustion chamber inside the cylinder to the fuel injection valve, and a cover pipe that covers the plurality of pipes collectively.

Description

Technology Field

[0001] The present invention relates to a piping structure for a fuel injection valve that injects fuel into the combustion chamber of a marine internal combustion engine. Background Technology

[0002] Conventionally, a fuel injection valve (hereinafter referred to as a fossil fuel injection valve) for injecting fossil fuels, such as heavy oil, into the combustion chamber inside the cylinder is formed in the upper part of a marine internal combustion engine. In addition, many pipes connected to the fossil fuel injection valve, such as a fossil fuel supply pipe, are piped in the upper part of the cylinder.

[0003] Furthermore, in the marine sector, in order to reduce carbon dioxide emissions from marine internal combustion engines, a type of marine internal combustion engine capable of being driven by burning alternative fuels instead of the fossil fuels conventionally used as marine fuel is being developed recently. The alternative fuel referred to here is, for example, a fuel that emits less carbon dioxide during combustion compared to fossil fuels, such as liquid ammonia, methanol, or liquefied petroleum gas (LPG). In the upper part of the cylinder of such a marine internal combustion engine, a fuel injection valve (hereinafter referred to as the alternative fuel injection valve) for injecting alternative fuel into the combustion chamber is formed in addition to the fossil fuel injection valve described above.

[0004] Generally, the alternative fuel injection valve has many pipes connected to it compared to the fossil fuel injection valve, such as a supply pipe for alternative fuel, a discharge pipe for a drain containing alternative fuel purged from the alternative fuel injection valve when fuel injection is interrupted (hereinafter referred to as the purge drain), and a supply pipe for high-pressure hydraulic fluid used to operate the alternative fuel injection valve. That is, the upper part of the cylinder where the alternative fuel injection valve is formed has many pipes connected compared to a type of marine internal combustion engine driven solely by the combustion of fossil fuel (see, for example, Non-Patent Literature 1). Prior art literature

[0005] Peter Rosenkvist, 「8G95ME-C10.5-LGIM」, Japanese Shipyard Seminar, MAN Energy Solutions, page 12 The problem to be solved

[0006] As a pipe connected to the alternative fuel injection valve described above, a double-structured pipe (hereinafter appropriately abbreviated as double pipe) is used, which basically combines an inner pipe through which fluid flows and an outer pipe covering said inner pipe. The double pipe is suitable as a pipe connected to the alternative fuel injection valve because the outer pipe can prevent leakage of the components of the alternative fuel flowing through the inner pipe (e.g., ammonia odor of liquid ammonia).

[0007] However, if the pipe structure is made double-walled, the outer diameter of the pipe inevitably increases. Furthermore, as the number of alternate fuel injection valves formed at the top of the cylinder increases, the number of double pipes required to be routed to the top of the cylinder also increases accordingly. Consequently, it is becoming difficult to secure the necessary piping space for the alternate fuel injection valves within the limited area of ​​the top of the cylinder.

[0008] The present invention is made in consideration of the above circumstances and aims to provide a piping structure that can reduce the piping space required for an alternative fuel injection valve. means of solving the problem

[0009] In order to achieve the objective by solving the problem described above, the piping structure related to the present invention is characterized by comprising a plurality of pipes including an alternative fuel pipe that is connected to a fuel injection valve formed on the upper part of a cylinder of a marine internal combustion engine and supplies alternative fuel injected from the fuel injection valve into a combustion chamber inside the cylinder to the fuel injection valve, and a cover pipe that covers the plurality of pipes collectively.

[0010] In addition, the piping structure related to the present invention is characterized in that, in the present invention, the internal space of the cover pipe is further divided into a first space in which a first pipe containing the alternative fuel is arranged among the plurality of pipes and a second space in which a second pipe other than the first pipe is arranged, and the alternative fuel pipe is classified into the first pipe.

[0011] In addition, the piping structure related to the present invention is characterized in that, in the invention, the internal space of the cover pipe is divided into a first space in which a first pipe containing the alternative fuel is arranged among the plurality of pipes for circulating the fluid, and a second space in which a second pipe other than the first pipe is arranged, and additionally provides a filler that is filled in the first space at a distance from the first pipe, and the alternative fuel pipe is classified into the first pipe.

[0012] In addition, the piping structure related to the present invention is characterized in that, in the invention, the alternative fuel is liquid ammonia.

[0013] In addition, the piping structure related to the present invention is characterized by further comprising a suction part that sucks in internal gas of the cover pipe in the above invention.

[0014] In addition, the piping structure related to the present invention is characterized in that, in the invention, it comprises a communication hole formed in the cover pipe and communicating the internal space of the cover pipe with the fuel injection valve, and a detection unit for detecting the components of the alternative fuel contained in the internal gas. Effects of the invention

[0015] According to the piping structure related to the present invention, the piping space required for the alternative fuel injection valve can be reduced, thereby providing an effect. Brief explanation of the drawing

[0016] FIG. 1 is a schematic diagram showing one configuration example of a marine internal combustion engine related to Embodiment 1 of the present invention. FIG. 2 is a schematic diagram showing an example of a piping structure related to Embodiment 1 of the present invention. FIG. 3 is a schematic cross-sectional diagram showing an example of a cross-sectional configuration of a piping structure related to Embodiment 1 of the present invention. FIG. 4 is a schematic cross-sectional diagram showing an example of a cross-sectional configuration of a piping structure related to Embodiment 2 of the present invention. FIG. 5 is a schematic cross-sectional diagram showing an example of a cross-sectional configuration of a piping structure related to Embodiment 3 of the present invention. Specific details for implementing the invention

[0017] Hereinafter, preferred embodiments of the piping structure related to the present invention will be described in detail with reference to the attached drawings. Furthermore, the present invention is not limited by these embodiments. Additionally, it should be noted that the drawings are schematic and that the relationships between the dimensions of each element and the ratios of each element may differ from reality. There may also be parts in which the relationships between dimensions or ratios differ from one another. Furthermore, in each drawing, the same reference numeral is assigned to identical components.

[0018] (Embodiment 1)

[0019] First, the configuration of a marine internal combustion engine equipped with a piping structure related to Embodiment 1 of the present invention will be described. FIG. 1 is a schematic diagram showing an example of the configuration of a marine internal combustion engine related to Embodiment 1 of the present invention. FIG. 1 also schematically illustrates the general configuration of the upper part of the cylinder in this marine internal combustion engine (1). The marine internal combustion engine (1) shown in FIG. 1 is a propulsion engine (main engine) that rotates a propulsion propeller (not shown) of a ship through a propeller shaft. For example, the marine internal combustion engine (1) is a 2-stroke internal combustion engine such as a known uniflow small exhaust crosshead diesel engine. As for the marine internal combustion engine (1), a 6-cylinder engine, etc., may be used, but the number of cylinders is not particularly limited. In addition, as for the operation control method of the marine internal combustion engine (1), a cam type or an electronic control type may be used, but is not particularly limited.

[0020] Also, the configuration of the upper part of the cylinder of the marine internal combustion engine (1) is the same for any cylinder (cylinder). Therefore, below, the configuration of the upper part of the cylinder of the marine internal combustion engine (1) will be explained for one of the cylinders.

[0021] As shown in FIG. 1, the marine internal combustion engine (1) is equipped with a cylinder (2), an exhaust valve box (3), and a moving valve device (4), etc. Additionally, the marine internal combustion engine (1) is equipped with a piston, etc. (not shown) inside the cylinder (2), and is equipped with a fossil fuel injection valve (5 to 7) and an alternative fuel injection valve (8 to 10), etc. at the top of the cylinder (2) (cylinder top (2a)).

[0022] The cylinder (2) functions as a cylinder in a marine internal combustion engine (1) and is composed of a cylinder liner, which is a cylindrical structure, and a cylinder cover, which is mounted on the upper part of the cylinder liner. The upper part of the cylinder (2a) shown in FIG. 1 corresponds to the upper part of the cylinder cover, which is a component of the cylinder (2). Although not specifically illustrated, the cylinder cover is joined to the cylinder liner by fastening members such as bolts. For example, the fastening members are arranged at multiple points along the outer circumference of the upper part of the cylinder (2a), and the cylinder cover and the cylinder liner are fastened at these multiple points. The cylinder (2) forms a cylindrical internal space in which a piston (not illustrated) reciprocates. The piston is formed to be able to freely reciprocate within the cylinder (2). Although not specifically illustrated, a piston rod is connected to the lower part of the piston, and the lower part of the piston rod is connected to a crankshaft through a cross head, etc. This crankshaft rotates in conjunction with the reciprocating motion of the piston, and accordingly, rotates the propeller shaft, etc.

[0023] Additionally, although not specifically illustrated, a combustion chamber of a marine internal combustion engine (1) is partitioned within the cylinder (2). Fuel or a mixed fluid containing water, etc., is injected into the combustion chamber from each of the fossil fuel injection valves (5 to 7) and alternative fuel injection valves (8 to 10) mounted on the upper part (2a) of the cylinder. Fossil fuels such as heavy oil or light oil may be used as fuels injected into the combustion chamber from each of the fossil fuel injection valves (5 to 7). Alternative fuels such as liquid ammonia, methanol, LPG, or hydrogen may be used as fuels injected into the combustion chamber from each of the alternative fuel injection valves (8 to 10). These alternative fuels are used to replace fossil fuels in order to reduce the emission of carbon dioxide from the marine internal combustion engine (1). The amount of carbon dioxide generated from the combustion of alternative fuels (emissions from internal combustion engines (1) for ships) is less than that from the combustion of fossil fuels.

[0024] As shown in FIG. 1, the exhaust valve box (3) is formed on the upper part of the cylinder (2a) in a manner that is enclosed within the fossil fuel injection valves (5 to 7) and alternative fuel injection valves (8 to 10). Although not specifically illustrated, an exhaust valve (not illustrated) that opens and closes the exhaust port of the combustion chamber in the cylinder (2) is supported inside the exhaust valve box (3) so that it can slide freely. Additionally, the exhaust valve box (3) has an exhaust gas passage that communicates the combustion chamber in the cylinder (2) and the exhaust manifold (not illustrated) through the exhaust valve. Gas after fuel combustion in the combustion chamber is discharged from the combustion chamber to the exhaust manifold through the exhaust valve box (3), etc. The exhaust manifold temporarily stores the exhaust gas received from the exhaust valve box (3) and converts the dynamic pressure of the exhaust gas into static pressure. The moving valve device (4) is formed on the upper part of the exhaust valve box (3), as shown in FIG. 1. The moving valve device (4) reciprocates the exhaust valve so that the exhaust valve described above can open and close the exhaust port of the combustion chamber in the cylinder (2).

[0025] Although not illustrated in FIG. 1, the upper part of the cylinder (2a) is piped with various pipes, such as a pipe for supplying working fluid to operate the operating valve device (4), a pipe for injecting fossil fuel into the combustion chamber from each of the fossil fuel injection valves (5 to 7), and a pipe for injecting alternative fuel into the combustion chamber from each of the alternative fuel injection valves (8 to 10). These pipes have a piping structure capable of withstanding the pressure of fluids such as working fluid or fuel being circulated. In particular, the pipe connected to each of the alternative fuel injection valves (8 to 10) has a double structure of an inner pipe through which fluid is circulated and an outer pipe covering said inner pipe, in order to prevent leakage of alternative fuel within the ship, such as in the engine room where the ship’s internal combustion engine (1) is installed. The detailed piping structure of the pipe connected to each of the alternative fuel injection valves (8 to 10) will be described later.

[0026] In the marine internal combustion engine (1) described above, a combustion gas such as air is introduced into the combustion chamber from a scavenging port (not shown) of a cylinder (2), and then the piston inside the cylinder (2) rises and the exhaust port of the combustion chamber is closed by the exhaust valve, thereby compressing the combustion gas inside the combustion chamber. Inside this combustion chamber, the compressed combustion gas and an injection liquid such as fuel injected from at least one of the fossil fuel injection valves (5 to 7) and alternative fuel injection valves (8 to 10) are mixed and combusted, and the piston descends due to combustion energy. The exhaust gas inside this combustion chamber is discharged to the exhaust manifold through the exhaust gas passage of the exhaust valve box (3) from the exhaust port at the timing when the exhaust port is opened by the exhaust valve.

[0027] (Piping structure)

[0028] Next, a piping structure related to Embodiment 1 of the present invention will be described. FIG. 2 is a schematic diagram showing an example of a piping structure related to Embodiment 1 of the present invention. FIG. 2 schematically illustrates a piping structure (11) related to Embodiment 1 of the present invention as viewed from above (on the upper side of the cylinder (2a)) of the cylinder (2) of the marine internal combustion engine (1) shown in FIG. 1. The piping structure (11) related to Embodiment 1 of the present invention is a pipe structure that is connected to each of the alternative fuel injection valves (8 to 10) among the fuel injection valves formed on the upper side (2a) of the cylinder of the marine internal combustion engine (1). As shown in FIG. 2, this piping structure (11) is provided with a plurality of pipes (12), a branch section (17), and a cover pipe (18). In addition, as shown in FIG. 2, the piping structure (11) is equipped with a suction part (20), a detection part (21), and an exhaust gas pipe (22).

[0029] A plurality of pipes (12) are pipes connected to an alternative fuel injection valve (each of the alternative fuel injection valves (8 to 10) shown in FIG. 1 and 2 in the present embodiment 1) formed in the upper part (2a) of the cylinder of a marine internal combustion engine (1). Specifically, as shown in FIG. 2, the plurality of pipes (12) include an alternative fuel pipe (13), a drain pipe (14), a hydraulic fluid pipe (15), and a sealing fluid pipe (16).

[0030] The alternative fuel pipe (13) is a pipe that supplies alternative fuel to each of the alternative fuel injection valves (8 to 10). The alternative fuel is, for example, liquid ammonia, methanol, LPG, or hydrogen, and is injected into the combustion chamber inside the cylinder (2) from each of the alternative fuel injection valves (8 to 10). The drain pipe (14) is a pipe for collecting the purge drain discharged from each of the alternative fuel injection valves (8 to 10). The purge drain is a drain containing the alternative fuel purged from the alternative fuel injection valve by injecting a purge gas, such as nitrogen, into the alternative fuel injection valve that is in a state where the injection of alternative fuel into the combustion chamber among the alternative fuel injection valves (8 to 10) is suspended. The hydraulic fluid pipe (15) is a pipe that supplies hydraulic fluid to each of the alternative fuel injection valves (8 to 10). The operating oil is an oil for operating the internal valve components related to the injection of alternative fuel in each of the alternative fuel injection valves (8 to 10). The sealing oil pipe (16) is a pipe that supplies sealing oil to each of the alternative fuel injection valves (8 to 10). The sealing oil is an oil for preventing leakage of alternative fuel from each of the alternative fuel injection valves (8 to 10).

[0031] Additionally, as shown in FIG. 2, a plurality of pipes (12) are branched to each of the alternative fuel injection valves (8 to 10) through a branching section (17). The branching section (17) branches the plurality of pipes (12) according to each alternative fuel injection valve formed in the upper part of the cylinder (2a). For example, as shown in FIG. 2, the branching section (17) branches the plurality of pipes (12) into a plurality of pipes (12A), a plurality of pipes (12B), and a plurality of pipes (12C) according to each of the three alternative fuel injection valves (8 to 10) in the upper part of the cylinder (2a).

[0032] A plurality of pipes (12A) are pipes branched from a plurality of pipes (12) prior to branching through a branching section (17) toward the alternative fuel injection valve (8). FIG. 3 is a schematic cross-sectional diagram showing an example of a cross-sectional configuration of a piping structure related to Embodiment 1 of the present invention. FIG. 3 schematically illustrates a cross-sectional view of the AA line of the portion branched toward the alternative fuel injection valve (8) among the piping structure (11) shown in FIG. 2. As shown in FIG. 3, the plurality of pipes (12A) include an alternative fuel pipe (13A), a drain pipe (14A), an operating fluid pipe (15A), and a sealing fluid pipe (16A).

[0033] The alternative fuel pipe (13A) is a pipe branched from the alternative fuel pipe (13) (see FIG. 2) included in the plurality of pipes (12) prior to branching, through a branching section (17) toward the alternative fuel injection valve (8). The outlet end of this alternative fuel pipe (13A) is connected to the alternative fuel injection valve (8) to supply alternative fuel to the internal passage of this alternative fuel injection valve (8). The drain pipe (14A) is a pipe branched from the drain pipe (14) (see FIG. 2) included in the plurality of pipes (12) prior to branching, through a branching section (17) toward the alternative fuel injection valve (8). The inlet end of this drain pipe (14A) is connected to the alternative fuel injection valve (8) to allow the purge drain discharged from this alternative fuel injection valve (8) to flow toward the drain treatment device. The hydraulic fluid pipe (15A) is a pipe branched from the hydraulic fluid pipe (15) (see FIG. 2) included in the plurality of pipes (12) prior to branching, through the branching section (17) toward the alternative fuel injection valve (8). The outlet end of this hydraulic fluid pipe (15A) is connected to the alternative fuel injection valve (8) to supply hydraulic fluid to this alternative fuel injection valve (8). The sealing fluid pipe (16A) is a pipe branched from the sealing fluid pipe (16) (see FIG. 2) included in the plurality of pipes (12) prior to branching, through the branching section (17) toward the alternative fuel injection valve (8). The outlet end of this sealing fluid pipe (16A) is connected to the alternative fuel injection valve (8) to supply sealing fluid to this alternative fuel injection valve (8).

[0034] A plurality of pipes (12A), including the alternative fuel pipe (13A) described above, are piped to the upper part of the cylinder (2a) along a piping path (hereinafter referred to as the first piping path) toward the alternative fuel injection valve (8) to be joined, while avoiding contact with the structure formed on the upper part of the cylinder (2a), as shown in FIG. 2. At this time, the alternative fuel pipe (13A), drain pipe (14A), hydraulic fluid pipe (15A), and sealing fluid pipe (16A) included in the plurality of pipes (12A) are piped side by side (e.g., in a row) so as to be close to each other, as shown in FIG. 3.

[0035] In addition, in the first piping path, the structure that must avoid contact with a plurality of pipes (12A) is a structure other than the replacement fuel injection valve (8) to be joined. Examples of such structures include fossil fuel injection valves (5 to 7), replacement fuel injection valves (9, 10), a valve device (4), an exhaust valve box (3), and an exhaust gas pipe (3a). Also, the exhaust gas pipe (3a) is a pipe that sends exhaust gas from the exhaust valve box (3) to the exhaust manifold.

[0036] The plurality of pipes (12B) are pipes branched from the plurality of pipes (12) prior to the branching to the alternative fuel injection valve (9) side through the branching section (17). Although not specifically illustrated, the plurality of pipes (12B) include an alternative fuel pipe, a drain pipe, an operating fluid pipe, and a sealing fluid pipe, just like the plurality of pipes (12A) shown in FIG. 3. These pipes are identical to the plurality of pipes (12A) described above, except that they are connected to the alternative fuel injection valve (9) instead of the alternative fuel injection valve (8).

[0037] Additionally, as shown in FIG. 2, a plurality of pipes (12B) are piped to the upper part of the cylinder (2a) along a piping path (hereinafter referred to as the second piping path) toward the replacement fuel injection valve (9) to be joined, while avoiding contact with the structure formed on the upper part of the cylinder (2a). At this time, each pipe included in the plurality of pipes (12A) is piped in parallel so as to be close to each other, just as in the case of the plurality of pipes (12A) described above (see FIG. 3). Also, in the second piping path, the structure that must avoid contact with the plurality of pipes (12B) is a structure other than the replacement fuel injection valve (9) to be joined. The structure is the same as in the case of the plurality of pipes (12A) described above, except that the replacement fuel injection valve (9) is replaced with the replacement fuel injection valve (8).

[0038] The plurality of pipes (12C) are pipes branched from the plurality of pipes (12) prior to branching to the alternative fuel injection valve (10) side through the branching section (17). Although not specifically illustrated, the plurality of pipes (12C) include an alternative fuel pipe, a drain pipe, an operating fluid pipe, and a sealing fluid pipe, just like the plurality of pipes (12A) shown in FIG. 3. These pipes are identical to the plurality of pipes (12A) described above, except that they are connected to the alternative fuel injection valve (10) instead of the alternative fuel injection valve (8).

[0039] Additionally, as shown in FIG. 2, a plurality of pipes (12C) are piped to the upper part of the cylinder (2a) along a piping path (hereinafter referred to as the third piping path) toward the replacement fuel injection valve (10) to be joined, while avoiding contact with the structure formed on the upper part of the cylinder (2a). At this time, each pipe included in the plurality of pipes (12C) is piped in parallel so as to be close to each other, just as in the case of the plurality of pipes (12A) described above (see FIG. 3). Also, in the third piping path, the structure that must avoid contact with the plurality of pipes (12C) is a structure other than the replacement fuel injection valve (10) to be joined. The structure is the same as in the case of the plurality of pipes (12A) described above, except that the replacement fuel injection valve (10) is replaced with the replacement fuel injection valve (8).

[0040] Although not specifically illustrated, among the multiple pipes (12) prior to the branch, the inlet end of the alternative fuel pipe (13) is connected to an alternative fuel supply device. The outlet end of the drain pipe (14) is connected to a drain treatment device that processes the purge drain collected from each of the alternative fuel injection valves (8 to 10). The drain treatment device performs a specific treatment on the purge drain, such as a treatment to recover oil components, etc. from the purge drain or a treatment to render the purge drain harmless (detoxification treatment). The inlet end of the hydraulic fluid pipe (15) is connected to an hydraulic fluid supply device. The inlet end of the sealing fluid pipe (16) is connected to a sealing fluid supply device.

[0041] The cover tube (18) is a tube that covers the plurality of tubes (12) described above collectively. In detail, as shown in FIG. 2, the cover tube (18) is composed of a portion that covers each tube included in the plurality of tubes (12), a portion that covers the plurality of tubes (12) before branching, a portion that covers the plurality of tubes (12A to 12C) after branching, and a portion that covers the branching portion (17). The cover tube (18) prevents the components of the alternative fuel from leaking into the ship, such as the engine room, from the tubes (e.g., alternative fuel tube (13) and drain tube (14)) through which the fluid containing the alternative fuel flows, among the entire plurality of tubes (12) including the plurality of tubes (12A to 12C) after branching. The component of the alternative fuel that leaks is the liquid component of the alternative fuel (e.g., liquid ammonia, etc.) or the vaporized component of the alternative fuel (e.g., vaporized gas of ammonia odor, etc.).

[0042] Additionally, as shown in FIG. 2, the cover pipe (18) is piped to the upper part of the cylinder (2a) so as to branch from the part covering the branch section (17) to the alternative fuel injection valve (8) side along the first piping path of the plurality of pipes (12A), to the alternative fuel injection valve (9) side along the second piping path of the plurality of pipes (12B), and to the alternative fuel injection valve (10) side along the third piping path of the plurality of pipes (12C). In this cover pipe (18), the branch end on the alternative fuel injection valve (8) side is connected to the alternative fuel injection valve (8), the branch end on the alternative fuel injection valve (9) side is connected to the alternative fuel injection valve (9), and the branch end on the alternative fuel injection valve (10) side is connected to the alternative fuel injection valve (10).

[0043] For example, as shown in FIG. 3, the cover tube (18) is formed in a hollow box shape and partitions an internal space that covers a plurality of tubes (12A) collectively. By covering a plurality of tubes (12A) collectively in its internal space, the cover tube (18) functions as a common cover tube for the replacement fuel tube (13A), drain tube (14A), working fluid tube (15A), and sealing fluid tube (16A) that are arranged in close proximity to each other. That is, the cover tube (18) is made of a double-structured tube consisting of an inner tube that allows fluid to flow through the replacement fuel tube (13A), drain tube (14A), working fluid tube (15A), and sealing fluid tube (16A) collectively, and an outer tube that covers the inner tube.

[0044] Although not specifically illustrated, the cover tube (18) covers multiple tubes (12, 12B, 12C) in the same manner as the multiple tubes (12A) shown in FIG. 3. Additionally, the volume of the internal space of the cover tube (18) may be increased or decreased depending on the number of tubes covered by the cover tube (18), or it may remain constant. From the perspective of ventilating the internal space of the cover tube (18), it is preferable that the volume of the internal space of the cover tube (18) be smaller within the range where it is possible to cover all of the multiple tubes (12).

[0045] Additionally, the cover tube (18) has a communication hole formed therein that connects to each of the alternative fuel injection valves (8 to 10). For example, as shown in FIG. 3, a communication hole (19) is formed at the end of the cover tube (18) on the side of the alternative fuel injection valve (8). The communication hole (19) is a hole that connects the internal space of the cover tube (18) with the alternative fuel injection valve (8). More specifically, the communication hole (19) is connected to a part of the alternative fuel injection valve (8), such as a component joint, through a pipe. Since this part is sealed by a sealing member such as an O-ring, leakage of the alternative fuel component from the internal passage of the alternative fuel injection valve (8) through this part does not typically occur. The communication hole (19) allows the leaked alternative fuel components to flow into the internal space of the cover pipe (18), even if the alternative fuel components leak through the said part. Accordingly, the leakage of alternative fuel from the alternative fuel injection valve (8) into the ship can be prevented. In addition, the alternative fuel components introduced into the said internal space are discharged out of the ship due to the action of the suction part (20) described later. Although not specifically illustrated, communication holes are also formed at each end of the cover pipe (18) on the side of the alternative fuel injection valves (9, 10), in the same manner as the communication hole (19) formed at the end of the alternative fuel injection valve (8) described above.

[0046] The suction section (20) is intended to ventilate the internal space of the cover tube (18). Specifically, the suction section (20) is configured by a suction pump, etc., and is formed in an exhaust gas pipe (22) that passes through the cover tube (18), as shown in FIG. 2. The exhaust gas pipe (22) is a pipe for discharging gas sucked in by the suction section (20) outside the vessel. The inlet end of this exhaust gas pipe (22) is connected to a specific part of the cover tube (18) (for example, a part before the branching of the cover tube (18)), as shown in FIG. 2. The outlet end of this exhaust gas pipe (22) is arranged to pass outside the vessel. The suction section (20) sucks gas (hereinafter referred to as internal gas) from the cover tube (18) into the exhaust gas pipe (22). At this time, the suction unit (20) sucks in the fluid that has flowed into the internal space of the cover tube (18) through each communication hole formed in the cover tube (18) (e.g., the communication hole (19) shown in FIG. 3) together with the internal gas of the cover tube (18). Accordingly, the suction unit (20) ventilates the internal space of the cover tube (18) and creates a negative pressure state in the internal space, thereby preventing leakage of internal gas from the cover tube (18) into the ship. The internal gas sucked in by the suction unit (20) is discharged from the cover tube (18) to the outside of the ship through the exhaust gas pipe (22).

[0047] Additionally, the suction capacity (ventilation capacity) of the suction unit (20) is set according to the classification of the ship equipped with the internal combustion engine (1) for the ship. For example, if the classification requires that the ventilation capacity of the annular space of the double tube be "capable of performing ventilation 30 times per hour," the suction unit (20) is adopted to have a suction capacity capable of ventilating the internal space of the cover tube (18) 30 times per hour. From the perspective of power saving and miniaturization of the suction unit (20), the volume of the internal space of the cover tube (18) is preferably as small as possible within the range where it is possible to cover multiple tubes (12).

[0048] The detection unit (21) detects the components of alternative fuel contained in the internal gas of the cover tube (18). Specifically, as shown in FIG. 2, the detection unit (21) is formed in the middle section of the exhaust gas tube (22) (for example, at the rear end in the suction direction of the suction unit (20). The detection unit (21) detects the presence or absence of alternative fuel components in the internal gas sucked from the cover tube (18) into the exhaust gas tube (22) by the suction unit (20). If the internal gas contains components of alternative fuel, the detection unit (21) notifies information indicating that the components have been detected. Additionally, if the internal gas does not contain components of alternative fuel, the detection unit (21) notifies information indicating that the components have not been detected.

[0049] Also, the information notified by the detector (21) may be sound information, light information, text information, or a combination of these. Additionally, the detector (21) may output information notifying this only when it detects the components of the alternative fuel in the internal gas.

[0050] As described above, in the piping structure related to Embodiment 1 of the present invention, a plurality of pipes including a replacement fuel pipe that supplies replacement fuel injected from the replacement fuel injection valve into the combustion chamber within the cylinder to the replacement fuel injection valve are connected to a replacement fuel injection valve formed on the upper part of a cylinder of a marine internal combustion engine, and are collectively covered by a cover pipe. Thus, a double-structure pipe (double pipe) can be formed in which each of the plurality of pipes connected to the replacement fuel injection valve is an inner pipe and a cover pipe common to these plurality of pipes is an outer pipe. Accordingly, compared to a conventional piping structure in which a plurality of double pipes are connected to the replacement fuel injection valve, the piping space required for the replacement fuel injection valve can be reduced. As a result, since the piping space for the double pipe connected to the replacement fuel injection valve can be easily secured within the limited area of ​​the upper part of the cylinder, even if the number of replacement fuel injection valves formed on the upper part of the cylinder increases, the double pipe required for the replacement fuel injection valve can be easily piped on the upper part of the cylinder.

[0051] In addition, the piping structure related to Embodiment 1 of the present invention is further provided with a suction part that sucks in internal gas of the cover pipe. Thus, the internal space of the cover pipe can be ventilated and a negative pressure state can be created through the operation of the suction part, and accordingly, the flow of fluid from the inside to the outside of the cover pipe can be suppressed, thereby further enhancing the effect of preventing leakage of alternative fuel components from the cover pipe into the ship.

[0052] In addition, in the piping structure related to Embodiment 1 of the present invention, a communication hole is formed in the cover pipe to communicate the internal space of the cover pipe with the alternative fuel injection valve, and the components of the alternative fuel contained in the internal gas of the cover pipe are detected by a detection unit. Thus, it is possible to detect whether the components of the alternative fuel are leaking into the internal space of the cover pipe, and accordingly, it is possible to collectively check whether the components of the alternative fuel have leaked from a plurality of pipes within the cover pipe or from the alternative fuel injection valve to which the plurality of pipes are connected.

[0053] (Embodiment 2)

[0054] Next, the piping structure related to Embodiment 2 of the present invention will be described. FIG. 4 is a schematic cross-sectional diagram showing an example of the cross-sectional configuration of the piping structure related to Embodiment 2 of the present invention. FIG. 4 shows, as an example of the piping structure (11A) related to Embodiment 2, the cross-sectional configuration of the part branched toward the alternative fuel injection valve (8), that is, the cross-sectional configuration corresponding to the AA line cross-section in the piping structure (11) shown in FIG. 2. As shown in FIG. 4, the piping structure (11A) related to Embodiment 2 further comprises a partitioning section (30) that partitions the internal space of the cover pipe (18), in addition to the configuration of the piping structure (11) related to Embodiment 1 described above (see FIG. 2 and 3). The other configurations are the same as those of Embodiment 1, and the same reference numerals are assigned to the same components.

[0055] The partition section (30) is formed in a plate shape, for example as shown in FIG. 4, and is formed inside the cover tube (18) to divide the internal space of the cover tube (18) into a first internal space (18A) (an example of the first space) in which a first tube is arranged and a second internal space (18B) (an example of the second space) in which a second tube is arranged. The first tube is a tube that flows a fluid containing alternative fuel among a plurality of tubes (12) (see FIG. 2) including a plurality of tubes (12A to 12C) after branching. Examples of the fluid include the alternative fuel itself or a drain containing alternative fuel (e.g., a purge drain). In addition, the second tube is a tube other than the first tube, and more specifically, a tube that flows a fluid not containing alternative fuel.

[0056] For example, when the plurality of pipes (12) are four pipes including the alternative fuel pipe (13), drain pipe (14), hydraulic fluid pipe (15), and sealing fluid pipe (16) described above, the first pipe is classified into the alternative fuel pipe (13) and its branch pipe (alternative fuel pipe (13A) shown in FIG. 4, etc.) that circulate alternative fuel among the plurality of pipes (12), and the drain pipe (14) and its branch pipe (drain pipe (14) shown in FIG. 4, etc.) that circulate purge drain discharged from each of the alternative fuel injection valves (8 to 10). In addition, among the plurality of pipes (12), the hydraulic fluid pipe (15) for circulating hydraulic fluid and its branch pipe (such as the hydraulic fluid pipe (15A) shown in FIG. 4) and the sealing fluid pipe (16) for circulating sealing fluid and its branch pipe (such as the sealing fluid pipe (16A) shown in FIG. 4) are classified.

[0057] The partition section (30) divides the internal space of the cover tube (18) into the first internal space (18A) and the second internal space (18B) described above, thereby dividing the plurality of tubes (12) into the first tube and the second tube, and isolating the first tube and the second tube from each other. For example, as shown in FIG. 4, the partition section (30) isolates the first internal space (18A), in which the replacement fuel tube (13A) and drain tube (14A) among the plurality of tubes (12A) exist, from the second internal space (18B), in which the hydraulic fluid tube (15A) and sealing fluid tube (16A) among the plurality of tubes (12A) exist. Accordingly, the partition (30) prevents internal gas from flowing into (leaking) the second internal space (18B) from the first internal space (18A) inside the cover tube (18). That is, the partition (30) limits the space to be ventilated by the suction part (20) described above within the internal space of the cover tube (18) to only the first internal space (18A), thereby reducing the volume of the space to be ventilated to the volume of the first internal space (18A).

[0058] Although not specifically illustrated, the partition (30) is formed inside the portion of the cover pipe (18) that covers the first pipe and the second pipe together. For example, in the piping structure (11A) related to the present embodiment 2, the partition (30) is formed inside the portion of the cover pipe (18) that covers the plurality of pipes (12) before branching, the portion of the portion of the cover pipe (18) that covers the plurality of pipes (12A) branched from the branching portion (17) toward the alternative fuel injection valve (8) side (see FIG. 4), the portion of the cover pipe (17) that covers the plurality of pipes (12B) branched from the branching portion (17) toward the alternative fuel injection valve (9) side, the portion of the cover pipe (12C) branched from the branching portion (17) toward the alternative fuel injection valve (10) side, and the portion of the cover pipe (17).

[0059] In addition, in the piping structure (11A) related to the present embodiment 2, the communication hole (19) described above is formed at the end of the first internal space (18A) of the cover pipe (18), for example, as shown in FIG. 4. This configuration is the same for each part covering each of the plurality of pipes (12B, 12C) of the cover pipe (18).

[0060] As explained above, in the piping structure related to Embodiment 2 of the present invention, the internal space of the cover pipe is divided by a partition formed inside the cover pipe into a first space in which the first pipe among the plurality of pipes is arranged and a second space in which the second pipe other than the first pipe is arranged, and the rest is the same as Embodiment 1 described above. Thus, while exhibiting the same functional effect as the piping structure related to Embodiment 1 described above, the inflow (leakage) of gas from the first space to the second space within the cover pipe can be prevented, and accordingly, the space within the internal space of the cover pipe that must be ventilated by the suction part can be limited only to the first space, thereby reducing the volume of the space that must be ventilated to the volume of the first space. As a result, power saving and miniaturization of the suction part used to ventilate the internal space of the cover pipe can be promoted.

[0061] (Embodiment 3)

[0062] Next, the piping structure related to Embodiment 3 of the present invention will be described. FIG. 5 is a schematic cross-sectional diagram showing an example of the cross-sectional configuration of the piping structure related to Embodiment 3 of the present invention. FIG. 5 shows, as an example of the piping structure (11B) related to Embodiment 3, the cross-sectional configuration of the part branched toward the alternative fuel injection valve (8), that is, the cross-sectional configuration corresponding to the AA line cross-section in the piping structure (11) shown in FIG. 2. As shown in FIG. 5, the piping structure (11B) related to Embodiment 3, in addition to the configuration of the piping structure (11) related to Embodiment 1 described above (see FIG. 2 and 3), additionally provides a filler (31) inside the cover pipe (18). The other configurations are the same as those of Embodiment 1, and the same reference numerals are assigned to the same parts.

[0063] The filling material (31) is filled (also called stuffing) in the first internal space (18A) at a distance from the first internal space (18B), while dividing the internal space of the cover tube (18) into a first internal space (18A) in which the first tube is arranged and a second internal space (18B) in which the second tube is arranged, as shown in FIG. 5, for example. In this embodiment 3, the definitions and classifications of the first tube and the second tube located in the internal space of the cover tube (18) are the same as those described in embodiment 2 above.

[0064] In detail, as shown in FIG. 5, the filler (31) is filled and fixed inside the cover tube (18) so as to surround the alternative fuel tube (13A) and drain tube (14A), which are classified as the first tube among the plurality of tubes (12A), with space between them. Such a filler (31) divides the internal space of the cover tube (18) into a first internal space (18A) in which the alternative fuel tube (13A) and drain tube (14A) exist, and a second internal space (18B) in which the hydraulic fluid tube (15A) and seal fluid tube (16A) exist, and isolates the first internal space (18A) and the second internal space (18B) from each other. Accordingly, the filling material (31) prevents the internal gas of the first internal space (18A) from flowing into (leaking out) the second internal space (18B) within the cover tube (18). In addition, the filling material (31) limits the space that must be ventilated by the suction part (20) described above within the internal space of the cover tube (18) to only the first internal space (18A), and further reduces the volume of this first internal space (18A) to the volume that must be ventilated compared to the case of the embodiment 2 described above (where the internal space of the cover tube (18) is simply partitioned by a plate-shaped partition part (30).

[0065] Although not specifically illustrated, the filler (31) is formed inside the portion of the cover pipe (18) that covers the first pipe and the second pipe together. For example, in the piping structure (11B) related to the present embodiment 3, the filler (31) is formed inside the portion of the cover pipe (18) that covers the plurality of pipes (12) before branching, the portion (see FIG. 5) that covers the plurality of pipes (12A) branched from the branching section (17) toward the alternative fuel injection valve (8), the portion (12B) that covers the plurality of pipes (12C) branched from the branching section (17) toward the alternative fuel injection valve (9), the portion that covers the plurality of pipes (12C) branched from the branching section (17) toward the alternative fuel injection valve (10), and the portion that covers the branching section (17).

[0066] In addition, in the piping structure (11B) related to the present embodiment 3, the communication hole (19) described above is formed at the end of the first internal space (18A) of the cover pipe (18), for example, as shown in FIG. 5. This configuration is the same for each part covering each of the plurality of pipes (12B, 12C) of the cover pipe (18).

[0067] As explained above, in the piping structure related to Embodiment 3 of the present invention, the internal space of the cover pipe is divided by the filling material filled inside the cover pipe into a first space in which the first pipe among the plurality of pipes is arranged and a second space in which a second pipe other than the first pipe is arranged, and a gap is created between the first pipe and the second space, and otherwise, the structure is the same as Embodiment 1 described above. Thus, while exhibiting the same functional effect as the piping structure related to Embodiment 1 described above, the first space can be narrowed while preventing the inflow (leakage) of gas from the first space to the second space within the cover pipe, and accordingly, the space within the internal space of the cover pipe that must be ventilated by the suction part is limited only to the first space, thereby reducing the volume of the first space. As a result, power saving and miniaturization of the suction part used to ventilate the internal space of the cover pipe can be easily promoted.

[0068] In addition, in embodiments 1 to 3 described above, a plurality of pipes (12) connected to each of the three alternative fuel injection valves (8 to 10) formed in the upper part of the cylinder (2a) were branched in three directions, but the present invention is not limited to this. For example, the plurality of pipes (12) may be branched in two directions or in three or more directions depending on the number of alternative fuel injection valves arranged in the upper part of the cylinder (2a). Alternatively, the plurality of pipes (12) may be connected to the alternative fuel injection valves in the upper part of the cylinder (2a) without being branched. Also, the cover pipe (18) may be branched in two or more directions, or not branched, just like the plurality of pipes (12).

[0069] Additionally, in embodiments 1 to 3 described above, the case in which four pipes including a replacement fuel pipe (13) and a drain pipe (14) are covered inside the cover pipe (18) was illustrated, but the present invention is not limited thereto. For example, the pipes covered inside the cover pipe (18) may be two or more pipes including a pipe that circulates a fluid containing replacement fuel, and the pipes may be the replacement fuel pipe (13) or the drain pipe (14).

[0070] In addition, in embodiments 1 to 3 described above, a cover tube (18) having a rectangular shape was exemplified, but the present invention is not limited to this. For example, the cover tube (18) may be a tube having a shape other than a rectangle, such as a circular or elliptical shape.

[0071] In addition, in embodiments 1 to 3 described above, the plurality of tubes (12) covered inside the cover tube (18) were arranged in a row, but the present invention is not limited to this. For example, these plurality of tubes (12) may be arranged in a row, or arranged in a row in a number of directions that intersect each other. In addition, these plurality of tubes (12) may be arranged adjacent to each other or arranged to be gathered together.

[0072] Furthermore, the present invention is not limited by the embodiments 1 to 3 described above, and configurations formed by appropriately combining each of the components described above are also included in the present invention. In addition, all other embodiments, examples, and operational techniques carried out by those skilled in the art based on embodiments 1 to 3 described above are all included within the scope of the present invention. Explanation of the symbols

[0073] 1 : Marine internal combustion engine 2 : Cylinder 2a: Upper part of cylinder 3: Exhaust valve box 3a: Exhaust gas pipe 4: Operating valve device 5, 6, 7: Fossil fuel injection valves 8, 9, 10: Alternate fuel injection valves 11, 11A, 11B: Piping structure 12, 12A, 12B, 12C: Multiple tubes 13, 13A: Replacement fuel line 14, 14A: Drain tube 15, 15A: Operating oil pipe 16, 16A : Time-related 17 : Branching section 18 : Cover tube 18A: First internal space 18B: Second interior space 19: Chimney hole 20 : Suction part 21 : Detector 22: Exhaust gas pipe 30 : Section 31 : Filling

Claims

Claim 1 A piping structure characterized by comprising a plurality of pipes including an alternative fuel pipe that is connected to a fuel injection valve formed at the upper part of a cylinder of a marine internal combustion engine and supplies alternative fuel injected from the fuel injection valve into a combustion chamber inside the cylinder to the fuel injection valve, and a cover pipe that covers the plurality of pipes collectively. Claim 2 A piping structure according to claim 1, further comprising a partition portion that divides the internal space of the cover pipe into a first space in which a first pipe containing a fluid containing the alternative fuel among the plurality of pipes is arranged and a second space in which a second pipe other than the first pipe is arranged, wherein the alternative fuel pipe is classified into the first pipe. Claim 3 A piping structure according to claim 1, wherein the internal space of the cover pipe is divided into a first space in which a first pipe containing a fluid containing the alternative fuel among the plurality of pipes is arranged and a second space in which a second pipe other than the first pipe is arranged, and additionally provided with a filler filled in the first space at a distance from the first pipe, and wherein the alternative fuel pipe is classified into the first pipe. Claim 4 A piping structure characterized in that, in any one of claims 1 to 3, the alternative fuel is liquid ammonia. Claim 5 A piping structure characterized by additionally comprising a suction part for sucking in internal gas of the cover pipe in any one of claims 1 to 3. Claim 6 A piping structure according to claim 5, characterized by having a communication hole formed in the cover tube and communicating the internal space of the cover tube with the fuel injection valve, and a detection unit for detecting the components of the alternative fuel contained in the internal gas.

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