Engine device

Abstract

This engine device comprises: an engine body that uses a toxic fuel; an engine room that houses the engine body; a safety valve that is provided to the engine body and opens in accordance with the internal pressure of the engine body; and a duct that guides gas discharged from the safety valve out of the engine room.

Description

Engine equipment

[0001] This application claims priority from Japanese Patent Application No. 2024-059254, filed on April 1, 2024, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 listed below discloses a reciprocating engine system that uses ammonia as fuel. This reciprocating engine system includes a reciprocating engine and a control device. The reciprocating engine has a cylinder that forms a combustion chamber, a piston that reciprocates within the cylinder, an ammonia fuel supply device that supplies gaseous ammonia to the cylinder and premixes it with air, and a liquid auxiliary fuel supply device that supplies liquid auxiliary fuel into the cylinder to ignite the ammonia. The control device performs multi-fuel combustion operation using the ammonia and the liquid auxiliary fuel when the compression end temperature within the cylinder is equal to or higher than a predetermined temperature at which combustion delay of the ammonia does not occur.

[0003] WO 2023 / 90218

[0004] In recent years, as a measure against global warming, the greenhouse gas carbon dioxide (CO ２ ) emissions are required to be reduced. ３ Ammonia is attracting attention as a new fuel that does not emit carbon dioxide when burned. Engines are equipped with various safety valves to prevent damage to the engine from pressure increases caused by internal gas explosions. However, ammonia is toxic, and if unburned ammonia leaks into the engine compartment through a safety valve, safety issues may arise.

[0005] The present invention has been made in view of the above circumstances, and has as its object to improve the safety of engine devices that use toxic fuels.

[0006] An engine device according to one aspect of the present invention comprises an engine body that uses toxic fuel, an engine room that houses the engine body, a safety valve that is provided in the engine body and opens in response to the internal pressure of the engine body, and a duct that guides gas released from the safety valve to the outside of the engine room.

[0007] In the engine device, the toxic fuel may be ammonia.

[0008] In the engine device, the engine body may be capable of switching between a first operation mode in which ammonia is used as fuel and a second operation mode in which a fuel other than ammonia is used.

[0009] The engine device may further include a purge gas inlet capable of introducing purge gas into the duct.

[0010] In the above engine device, the engine body includes a cylinder that forms a combustion chamber, an intake passage that supplies pre-combustion gas to the combustion chamber, an exhaust passage that discharges post-combustion gas from the combustion chamber, a piston that reciprocates within the cylinder, a crank connected to the piston, and a crankcase that houses the crank, and the safety valve and the duct may be provided in at least one of the cylinder, the intake passage, the exhaust passage, and the crankcase.

[0011] In the above engine device, the safety valves may include an intake safety valve provided in the intake passage and a crankcase safety valve provided in the crankcase, and the ducts may include an intake safety valve duct into which gas released from the intake safety valve is introduced and a crankcase safety valve duct into which gas released from the crankcase safety valve is introduced, and the intake safety valve duct and the crankcase safety valve duct may be connected to each other and extend to the outside of the engine compartment.

[0012] In the above engine device, the safety valves may include a cylinder safety valve provided in the cylinder and an exhaust safety valve provided in the exhaust path, and the ducts may include a cylinder safety valve duct into which gas released from the cylinder safety valve is introduced, and an exhaust safety valve duct into which gas released from the exhaust safety valve is introduced, and the cylinder safety valve duct and the exhaust safety valve duct may be provided independently of the intake safety valve duct and the crankcase safety valve duct which are connected to each other.

[0013] According to the above aspect of the present invention, it is possible to improve the safety of an engine device that uses toxic fuel.

[0014] FIG. 1 is a configuration diagram of an engine device according to one embodiment. FIG. 2 is an explanatory diagram illustrating operation in a diesel operation mode of the engine device according to one embodiment. FIG. 3 is an explanatory diagram illustrating operation in an ammonia operation mode of the engine device according to one embodiment. FIG. 4 is a cross-sectional configuration diagram of an engine body according to one embodiment. FIG. 5 is a cross-sectional plan view of the vicinity of an attachment position of a crankcase safety valve according to one embodiment. FIG. 6 is a cross-sectional plan view of the vicinity of an attachment position of an air intake safety valve according to one embodiment. FIG. 7 is a system diagram of intake and exhaust of an engine device according to one embodiment.

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0016] Fig. 1 is a configuration diagram of an engine system 1 according to one embodiment. As shown in Fig. 1, the engine system 1 includes an engine body 2 and a control device 3. The engine system 1 is a reciprocating engine, and is used, for example, as a marine engine that directly or indirectly drives a propeller. Note that the engine system 1 may also be a power generation engine that drives a generator.

[0017] The engine device 1 generally includes a cylinder 11 that forms a combustion chamber 10, a piston 12 that reciprocates within the cylinder 11, a crank 13 connected to the piston 12, a rotation detection sensor 14 that detects the rotation of the crank 13, and a torque detection sensor 15 that detects the torque of the crank 13. The shaft of the crank 13 is connected to, for example, a propeller of a ship.

[0018] An intake passage 20 and an exhaust passage 30 are connected to a cylinder head 16 of the cylinder 11. An intake valve 21 that opens and closes the intake passage 20 and an exhaust valve 31 that opens and closes the exhaust passage 30 are also provided in the cylinder head 16. A liquid fuel injection valve 53 that injects liquid auxiliary fuel into the combustion chamber 10 and an ignition device 55 are also provided in the cylinder head 16. The ignition device 55 is, for example, a micro-pilot oil injection valve, and is used in the ammonia operation mode (first operation mode) described below.

[0019] The air intake passage 20 includes a compressor 22 that compresses air for combustion, an air cooler 23 installed downstream of the compressor 22, and a fuel gas injection valve 43 installed downstream of the air cooler 23. The fuel gas injection valve 43 injects gaseous ammonia, which serves as fuel, into the air intake passage 20. The gaseous ammonia is premixed with compressed air in the air intake passage 20 to form an air-fuel mixture, which is then supplied into the cylinder 11.

[0020] The air cooler 23 may be an air cooler / heater that not only cools air with cold water but also heats air with hot water, a heater, or the like. If necessary, an air heater 24 may be installed upstream of the compressor 22 in the air intake passage 20. The air heater 24 may have, for example, a cooling / heating system 25 that uses refrigerant that has exchanged heat with the engine body 2 as a heat source.

[0021] The exhaust passage 30 includes a turbine 33 that is rotated by the exhaust gas discharged from the combustion chamber 10, and a catalytic treatment device 60 that is installed downstream of the turbine 33 and treats substances contained in the exhaust gas. The rotating shaft of the turbine 33 is connected to the compressor 22, and the exhaust gas serves as a rotation source to rotate the compressor 22. In other words, the turbine 33 and the compressor 22 constitute a turbocharger 4.

[0022] The catalytic treatment device 60 uses a catalyst to treat specific substances such as nitrogen oxides (NOx), nitrous oxide, and unburned ammonia that are generated by the combustion of ammonia and liquid auxiliary fuel. The catalytic treatment device 60 is equipped with a detection sensor 60a that detects the specific substances.

[0023] The engine body 2 includes an ammonia fuel supply device 40 that supplies ammonia into the cylinder 11, and a liquid auxiliary fuel supply device 50 that supplies liquid auxiliary fuel that ignites the ammonia into the cylinder 11. The ammonia fuel supply device 40 generally includes an ammonia tank 41, a vaporizer 42, and a fuel gas injection valve 43.

[0024] Ammonia tank 41 stores liquid ammonia. Vaporizer 42 vaporizes the liquid ammonia discharged from ammonia tank 41 to generate gaseous ammonia. Vaporizer 42 may include a pressure pump that pressurizes the gaseous ammonia. Vaporizer 42 is connected to fuel gas injection valve 43 via an ammonia supply path 44. Ammonia supply path 44 includes a regulator 44a and a pressure sensor 44b installed downstream of regulator 44a.

[0025] The ammonia supply path 44 also includes a second ammonia supply path 45 that branches off upstream of the regulator 44a. The second ammonia supply path 45 is connected to the above-described catalytic treatment device 60. The second ammonia supply path 45 includes a regulator 45a and a pressure sensor 45b that is installed downstream of the regulator 45a.

[0026] The exhaust gas contains unburned ammonia and nitrogen oxides. In the catalytic treatment device 60, the unburned ammonia acts as a reducing agent that removes oxygen from the nitrogen oxides. When the rate at which unburned ammonia is generated is insufficient compared to the rate at which nitrogen oxides are generated, the shortage of gaseous ammonia is injected from the second ammonia supply passage 45 into the catalytic treatment device 60. As a result, the nitrogen oxides are reduced by the unburned ammonia, and the unburned ammonia is oxidized by the oxygen in the exhaust gas and rendered harmless.

[0027] The liquid auxiliary fuel supply device 50 includes a liquid auxiliary fuel tank 51, a first liquid fuel supply pump 52, a liquid fuel injection valve 53, a second liquid fuel supply pump 54, and an ignition device 55. The liquid auxiliary fuel tank 51 stores liquid auxiliary fuel such as heavy oil, light oil, or gasoline. The first liquid fuel supply pump 52 supplies the liquid auxiliary fuel stored in the liquid auxiliary fuel tank 51 to the liquid fuel injection valve 53.

[0028] The liquid fuel injection valve 53 is, for example, a mechanical fuel injection device used in a diesel operation mode (second operation mode) described later. The second liquid fuel supply pump 54 supplies the liquid auxiliary fuel stored in the liquid auxiliary fuel tank 51 to the ignition device 55. The ignition device 55 is, for example, a common rail fuel injection device used in an ammonia operation mode.

[0029] The control device 3 is realized by, for example, a processor such as a central processing unit (CPU) executing a program stored in a storage unit. Alternatively, the control device 3 may be realized by hardware such as a large-scale integration (LSI), an application-specific integrated circuit (ASIC), or a field-programmable gate array (FPGA).

[0030] The storage unit is realized by, for example, a hard disk drive (HDD), a flash memory, an electrically erasable programmable read-only memory (EEPROM), a read-only memory (ROM), a random access memory (RAM), etc. The storage unit stores firmware, programs executed by the processor, etc.

[0031] The control device 3 derives the output (work load [kW]) for the current load based on, for example, the rotation speed detected by the rotation detection sensor 14 and the torque detected by the torque detection sensor 15, and derives the load factor based on this current output and the rated output stored in advance in a storage unit. The load factor is derived, for example, by dividing the current output by the rated output.

[0032] The control device 3 performs feedback control of the boost pressure based on the derived boost pressure target value based on the load factor of the engine body 2 and the boost pressure measured by a pressure gauge (not shown). The boost pressure target value derivation information is information that indicates a predetermined relationship between the load factor and the boost pressure target value. This information is stored in advance in a storage unit as, for example, a map or a function. As a result, the control device 3 supplies fuel based on the load factor of the internal combustion engine during operation.

[0033] The engine device 1 having the above configuration can be switched between an ammonia operation mode (first operation mode) in which the fuel used contains ammonia, and a diesel operation mode (second operation mode) in which a liquid auxiliary fuel (heavy oil, etc.) is used. Note that, since ammonia is more difficult to combust than the liquid auxiliary fuel (heavy oil, etc.), in the ammonia operation mode, a mixed combustion operation using ammonia and the liquid auxiliary fuel is performed. For this reason, the ammonia operation mode is also called a mixed combustion operation mode.

[0034] In the ammonia operation mode (co-firing operation mode), the maximum co-firing ratio of ammonia near the maximum output is 80% or more in terms of heat amount ratio.

[0035] 2 is an explanatory diagram illustrating the operation of the engine system 1 in a diesel operation mode according to one embodiment. As shown in FIG. 2, in the diesel operation mode, liquid auxiliary fuel is injected from the liquid fuel injection valve 53 into the combustion chamber 10, and is ignited and burned in the compressed air compressed by the piston 12. At this time, the fuel gas injection valve 43 is stopped.

[0036] 3 is an explanatory diagram illustrating the operation of the engine system 1 in the ammonia operation mode according to one embodiment. As shown in FIG. 3, in the ammonia operation mode, gaseous ammonia is injected from the fuel gas injector 43 into the air intake passage 20 and premixed with air before the combustion chamber 10. Next, liquid auxiliary fuel for ignition is injected from the ignition device 55 into the combustion chamber 10, and the air-fuel mixture compressed by the piston 12 is ignited and burned. At this time, the liquid fuel injector 53 is stopped.

[0037] Fig. 4 is a cross-sectional view of an engine body 2 according to one embodiment. As shown in Fig. 4, the engine body 2 includes a cylinder 11 that defines a combustion chamber 10, a piston 12 that reciprocates within the cylinder 11, a crank 13 connected to the piston 12, and a crankcase 70 that houses the crank 13. The crank 13 is connected to the piston 12 via a connecting rod 13a. The dotted arrows in Fig. 4 indicate the flow of blow-by gas. Blow-by gas is gas that leaks into the crankcase 70 from the gap between the piston 12 and the cylinder 11.

[0038] The bottom of the crankcase 70 is formed by an oil pan 71. The oil pan 71 stores lubricating oil to be supplied to sliding parts such as the crank 13. The crankcase 70 contains a crank chamber 72 and a cam chamber 73. The crank chamber 72 houses the crank 13. The cam chamber 73 houses a cam mechanism 80 that drives the exhaust valve 31. The cam chamber 73 is located above the crank chamber 72 and is in communication with the crank chamber 72.

[0039] The cam mechanism 80 includes a cam 81 that rotates in conjunction with the crank 13, a tappet roller mechanism 82 that contacts the circumferential surface of the cam 81, and a push rod 83 that is pushed up by the tappet roller mechanism 82. The push rod 83 is disposed in a through hole 74 formed in the cylinder head 16, and its tip extends into the head cover 17 attached to the top surface of the cylinder head 16.

[0040] A rocker arm 84 and a valve spring 85 are housed within the head cover 17. The valve spring 85 urges the exhaust valve 31 upward, closing the exhaust communication passage 30a that communicates with the exhaust path 30. When the rocker arm 84 is pushed up by the tip of the push rod 83, it pushes the exhaust valve 31 down against the urging of the valve spring 85, opening the exhaust communication passage 30a. Although not shown, the cam mechanism 80 also drives the intake valve 21 (see FIG. 1) using a similar mechanism.

[0041] The engine body 2 is provided with an air intake trunk 20a that is separated from the crank chamber 72 and the cam chamber 73 by partitions. The air intake trunk 20a is connected to the air intake passage 20. The air intake trunk 20a is connected to the cylinders 11. The engine body 2 is provided with a plurality of cylinders 11, and gas supplied to the air intake trunk 20a is supplied to each cylinder 11. The number of cylinders 11 is, for example, six, but is not limited to six. One crankcase 70 is provided for the plurality of cylinders 11 (for example, six).

[0042] The engine body 2 configured as described above is provided with a safety valve 90 that opens in response to the internal pressure of the engine body 2. The safety valve 90 releases pressurized gas to the outside of the engine body 2 to prevent damage to the engine body 2 from a pressure increase caused by, for example, an explosion of internal gas in the engine body 2. Specifically, the crankcase 70 is provided with a crankcase safety valve 90A that opens in response to the internal pressure of the crank chamber 72. Furthermore, the air intake path 20 is provided with an air intake safety valve 90B that opens in response to the internal pressure of the air intake trunk 20a.

[0043] Figure 5 is a cross-sectional plan view of the vicinity of the mounting position of a crankcase safety valve 90A according to one embodiment. As shown in Figure 5, an opening 70a is formed in the engine body 2. The safety valve 90 is mounted to the engine body 2 via a closure plate 91 having a communication hole 92 that communicates with the opening 70a. The gap between the engine body 2 and the closure plate 91 is airtightly sealed by a seal member 93.

[0044] Specifically, in the crankcase 70, an opening 70a is formed in a side wall of the crankcase 70. The opening 70a is closed by a closing plate 91A with a seal member 93A sandwiched therebetween. The closing plate 91A is also referred to as a crank door. A communication hole 92A is formed in the closing plate 91A. The crankcase safety valve 90A is attached to the closing plate 91A so as to close the communication hole 92A from the outside.

[0045] The communication hole 92A is formed with a diameter that allows the crankcase safety valve 90A to be attached, but a plurality of such valves may be formed in the closure plate 91A to ensure a flow path area that corresponds to the volume of the crank chamber 72. In other words, a plurality of crankcase safety valves 90A may also be attached to the closure plate 91A in correspondence with the communication holes 92A.

[0046] A duct 100 is connected to the outside of the closure plate 91. The duct 100 guides the gas released from the safety valve 90 to the outside of an engine compartment 110 (see FIG. 7 described later). The duct 100 includes a connection duct 101 that surrounds the safety valve 90, and a duct body 102 that is connected to the connection duct 101. The connection duct 101 and the duct body 102 are flange-connected. This makes it easier for the duct 100 to meet its pressure-resistance specifications. In addition, the mating surfaces of the flanges of the connection duct 101 and the duct body 102 are airtightly sealed by a seal member 103.

[0047] Specifically, in the crankcase 70, the crankcase safety valve 90A is surrounded by a connecting duct 101A connected to the outside of a closing plate 91A. The connecting duct 101A is flange-connected to a duct body 102A with a seal member 103A sandwiched therebetween. Note that, when there are multiple crankcase safety valves 90A, multiple connecting ducts 101A are attached to the closing plate 91A in correspondence with the crankcase safety valves 90A. Multiple duct bodies 102A may be provided in correspondence with the connecting ducts 101A, or may include one header pipe connected to each connecting duct 101A.

[0048] Figure 6 is a cross-sectional plan view of the vicinity of the mounting position of an air supply safety valve 90B according to one embodiment. As shown in Figure 6, an air supply safety valve 90B is also mounted to the air supply trunk 20a in a similar structure to the crankcase 70. Specifically, an opening 20b is formed in the air supply trunk 20a. The opening 20b is closed by a closing plate 91B with a seal member 93B sandwiched therebetween. A communication hole 92B is formed in the closing plate 91B. The air supply safety valve 90B is mounted to the closing plate 91B so as to block the communication hole 92B from the outside.

[0049] The intake safety valve 90B is surrounded by a connecting duct 101B connected to the outside of a closing plate 91B. The connecting duct 101B is flange-connected to a duct body 102B with a seal member 103B sandwiched therebetween. Note that, like the crankcase safety valve 90A, multiple intake safety valves 90B may be provided, and in that case, multiple connecting ducts 101B may be attached to the closing plate 91B corresponding to the intake safety valves 90B. Furthermore, multiple duct bodies 102B may be provided corresponding to the connecting ducts 101B, or may include one header pipe connected to each connecting duct 101B.

[0050] 7 is a system diagram of intake and exhaust air of an engine system 1 according to one embodiment. As shown in FIG. 7, the engine body 2 is provided with a crankcase safety valve 90A, an intake safety valve 90B, a cylinder safety valve 90C, and an exhaust safety valve 90D. Gas released from each safety valve 90 is guided to the outside of an engine room 110 via each duct 100. In the case of a ship, the area outside the engine room 110 is outside the ship. The duct 100 may be connected to the ship's chimney outside the engine room 110, or to a device such as a scrubber that dissolves ammonia in liquid to neutralize it.

[0051] The cylinder safety valve 90C is attached to the cylinder 11 and opens in response to the internal pressure of the cylinder 11. Gas released from the cylinder safety valve 90C is guided to the outside of the engine compartment 110 via a cylinder safety valve duct 100C. The exhaust safety valve 90D is attached to the exhaust path 30 and opens in response to the internal pressure of the exhaust path 30. The exhaust safety valve 90D is provided downstream of the turbine 33, but may be provided upstream of the turbine 33. The gas released from the exhaust safety valve 90D is guided to the outside of the engine compartment 110 via the exhaust safety valve duct 100D.

[0052] The crankcase safety valve duct 100A and the intake safety valve duct 100B are connected to each other and extend to the outside of the engine compartment 110. In other words, the crankcase safety valve duct 100A and the intake safety valve duct 100B join together downstream. On the other hand, the cylinder safety valve duct 100C and the exhaust safety valve duct 100D are provided independently of the crankcase safety valve duct 100A and the intake safety valve duct 100B.

[0053] The engine body 2 includes a purge gas introduction section 120 that can introduce purge gas into the duct 100. By introducing the purge gas into the duct 100, the purge gas introduction section 120 discharges gases that are toxic to the human body and that are retained in the duct 100 to the outside of the engine compartment 110. An example of the purge gas is an inert gas such as nitrogen. The purge gas introduction section 120 includes a purge gas introduction passage 121 connected to the duct 100 and an on-off valve 122 that opens and closes the purge gas introduction passage 121.

[0054] The engine system 1 includes, as purge gas introduction sections 120, a first purge gas introduction section 120A that introduces purge gas into the crankcase safety valve duct 100A, a second purge gas introduction section 120B that introduces purge gas into the intake safety valve duct 100B, a third purge gas introduction section 120C that introduces purge gas into the cylinder safety valve duct 100C, and a fourth purge gas introduction section 120D that introduces purge gas into the exhaust safety valve duct 100D. When the crankcase safety valve duct 100A and the intake safety valve duct 100B join together as in this embodiment, the first purge gas introduction section 120A and the second purge gas introduction section 120B may be a common introduction section.

[0055] As described above, the engine device 1 according to this embodiment includes the engine body 2 that uses toxic fuel, the engine compartment 110 that houses the engine body 2, the safety valve 90 that is provided in the engine body 2 and opens in response to the internal pressure of the engine body 2, and the duct 100 that guides gas released from the safety valve 90 to the outside of the engine compartment 110. With this configuration, the gas released from the safety valve 90 is guided to the outside of the engine compartment 110 through the duct 100, so that the toxic gas does not accumulate in the engine compartment 110. This can improve the safety of the engine device 1 that uses toxic fuel.

[0056] In this embodiment, the toxic fuel is ammonia. This configuration can improve the safety of the engine device 1 that uses ammonia as fuel, which does not generate carbon dioxide when burned. Note that the toxic fuel is not limited to ammonia, and may be, for example, methanol.

[0057] In the present embodiment, the engine body 2 can switch between a first operation mode using ammonia as fuel and a second operation mode using a fuel other than ammonia. According to this configuration, the operation mode can be switched between the first operation mode using ammonia as fuel and the second operation mode using a fuel other than ammonia as needed, and operation can be continued.

[0058] Furthermore, in this embodiment, a purge gas inlet 120 capable of introducing purge gas into the duct 100 is provided. With this configuration, toxic gas remaining in the duct 100 can be actively pushed out by the purge gas and discharged to the outside of the engine compartment 110.

[0059] In this embodiment, the engine body 2 includes a cylinder 11 that forms a combustion chamber 10, an intake passage 20 that supplies pre-combustion gas to the combustion chamber 10, an exhaust passage 30 that discharges post-combustion gas from the combustion chamber 10, a piston 12 that reciprocates within the cylinder 11, a crank 13 connected to the piston 12, and a crankcase 70 that houses the crank 13. The safety valve 90 and the duct 100 are provided in at least one (in this embodiment, all) of the cylinder 11, the intake passage 20, the exhaust passage 30, and the crankcase 70. With this configuration, gas released from the various safety valves of the engine body 2 can be guided to the outside of the engine compartment 110.

[0060] In addition, in this embodiment, the safety valve 90 includes an intake safety valve 90B provided in the intake passage 20 and a crankcase safety valve 90A provided in the crankcase 70, and the duct 100 includes an intake safety valve duct 100B into which gas released from the intake safety valve 90B is introduced and a crankcase safety valve duct 100A into which gas released from the crankcase safety valve 90A is introduced, with the intake safety valve duct 100B and the crankcase safety valve duct 100A being connected to each other and extending to the outside of the engine compartment 110. With this configuration, the intake safety valve duct 100B and the crankcase safety valve duct 100A merge into one duct, thereby reducing the space occupied by the duct 100 within the engine compartment 110. Furthermore, the intake safety valve duct 100B and the crankcase safety valve duct 100A are positioned close to each other, making it easy to merge them.

[0061] In this embodiment, the safety valve 90 includes a cylinder safety valve 90C provided in the cylinder 11 and an exhaust safety valve 90D provided in the exhaust path 30, and the duct 100 includes a cylinder safety valve duct 100C into which gas released from the cylinder safety valve 90C is introduced and an exhaust safety valve duct 100D into which gas released from the exhaust safety valve 90D is introduced, with the cylinder safety valve duct 100C and the exhaust safety valve duct 100D being provided independently of the intake safety valve duct 100B and the crankcase safety valve duct 100A which are connected to each other. The cylinder safety valve duct 100C and the exhaust safety valve duct 100D are required to have higher pressure resistance than the intake safety valve duct 100B and the crankcase safety valve duct 100A, so providing them independently makes it easier to meet the pressure resistance specifications.

[0062] While preferred embodiments of the present invention have been described and illustrated, it should be understood that they are illustrative of the present invention and should not be considered limiting. Additions, omissions, substitutions, and other modifications may be made without departing from the scope of the present invention. While a reciprocating engine has been described as a preferred embodiment, the same principles apply to engines other than reciprocating engines. Accordingly, the present invention should not be deemed limited by the foregoing description, but rather by the scope of the appended claims.

[0063] REFERENCE SIGNS LIST 1 engine device 2 engine body 10 combustion chamber 11 cylinder 12 piston 13 crank 20 intake passage 30 exhaust passage 70 crankcase 90 safety valve 90A crankcase safety valve 90B intake safety valve 90C cylinder safety valve 90D exhaust safety valve 100 duct 100A crankcase safety valve duct 100B intake safety valve duct 100C cylinder safety valve duct 100D exhaust safety valve duct 110 engine compartment 120 purge gas introduction section 120A first purge gas introduction section 120B second purge gas introduction section 120C third purge gas introduction section 120D fourth purge gas introduction section

Claims

1. An engine device comprising: an engine body that uses toxic fuel; an engine room that houses the engine body; a safety valve that is provided in the engine body and opens in response to the internal pressure of the engine body; and a duct that guides gas released from the safety valve to the outside of the engine room.

2. The engine device according to claim 1, wherein the toxic fuel is ammonia.

3. The engine device according to claim 2, wherein the engine body is capable of switching between a first operation mode in which ammonia is used as fuel and a second operation mode in which a fuel other than ammonia is used.

4. The engine device according to any one of claims 1 to 3, further comprising a purge gas inlet capable of introducing purge gas into the duct.

5. An engine device as claimed in any one of claims 1 to 3, wherein the engine body comprises: a cylinder forming a combustion chamber; an intake passage for supplying pre-combustion gas to the combustion chamber; an exhaust passage for discharging post-combustion gas from the combustion chamber; a piston that reciprocates within the cylinder; a crank connected to the piston; and a crankcase that houses the crank; and the safety valve and the duct are provided in at least one of the cylinder, the intake passage, the exhaust passage, and the crankcase.

6. An engine device according to claim 5, wherein the safety valves include an intake safety valve provided in the intake passage and a crankcase safety valve provided in the crankcase, and the ducts include an intake safety valve duct into which gas released from the intake safety valve is introduced and a crankcase safety valve duct into which gas released from the crankcase safety valve is introduced, and the intake safety valve duct and the crankcase safety valve duct are connected to each other and extend to the outside of the engine compartment.

7. An engine device according to claim 6, wherein the safety valves comprise a cylinder safety valve provided in the cylinder and an exhaust safety valve provided in the exhaust path, and the ducts comprise a cylinder safety valve duct into which gas released from the cylinder safety valve is introduced and an exhaust safety valve duct into which gas released from the exhaust safety valve is introduced, and the cylinder safety valve duct and the exhaust safety valve duct are provided independently of the air intake safety valve duct and the crankcase safety valve duct which are connected to each other.

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