Lubricating oil supply device, internal combustion engine, and ammonia separation method

Abstract

A lubricating oil supply device according to an embodiment is configured to: transfer an ammonia-containing lubricating oil from a reciprocating engine that operates by using ammonia as fuel; separate ammonia from the ammonia-containing lubricating oil; and transfer the lubricating oil, from which the ammonia has been separated, to the reciprocating engine.

Description

Lubricating oil supply device, internal combustion engine, and ammonia separation method

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to a lubricating oil supply system, an internal combustion engine, and an ammonia separation method.

[0002] Lubricating oil is known as a substance that prevents performance deterioration in reciprocating engines. Lubricating oil reduces friction by penetrating into the gap between the piston and the inner surface of the cylinder inside the reciprocating engine. Lubricating oil discharged from a reciprocating engine is reused after sludge and other contaminants are removed.

[0003] Patent Document 1 discloses a lubricating oil purifier that purifies lubricating oil for a propulsion engine of a ship.

[0004] Japanese Patent Application Publication No. 2020-516514

[0005] When lubricating oil is used in a reciprocating engine that uses ammonia as fuel, ammonia may dissolve in the lubricating oil discharged from the reciprocating engine. Since ammonia is likely to accelerate the deterioration of the lubricating oil, it is preferable to separate ammonia from the lubricating oil to be reused. However, it is difficult to separate ammonia from the lubricating oil using a conventional lubricating oil purifier.

[0006] An object of an embodiment of the present invention is to provide a technology for separating ammonia from lubricating oil.

[0007] A lubricating oil supplying device of a first aspect according to an embodiment is a lubricating oil supplying device configured to transfer lubricating oil containing ammonia from a reciprocating engine driven by ammonia as fuel, separate the ammonia from the lubricating oil containing ammonia, and transfer the lubricating oil from which the ammonia has been separated to the reciprocating engine.

[0008] In a second aspect of the embodiment, the lubricating oil supply device according to the first aspect includes a tank for storing the lubricating oil containing the ammonia transferred from the reciprocating engine, a temperature adjustment unit configured to adjust the temperature of the lubricating oil in the tank so that the ammonia evaporates from the lubricating oil in the tank, and a fan for discharging the ammonia contained in the gas in the tank from the tank.

[0009] In a third aspect of the embodiment, the lubricating oil supply device described in the second aspect further includes a concentration meter that acquires the concentration of ammonia contained in the lubricating oil in the tank, and the temperature adjustment unit is configured to adjust the temperature of the lubricating oil in the tank based on the concentration.

[0010] In a fourth aspect of the embodiment, the lubricating oil supply device according to the first aspect includes a tank for storing the lubricating oil containing the ammonia transferred from the reciprocating engine, a pressure adjusting unit configured to adjust the pressure of the gas in the tank so that the ammonia evaporates from the lubricating oil in the tank, and a fan for discharging the ammonia contained in the gas in the tank.

[0011] In a fifth aspect of the embodiment, the lubricating oil supply device described in the fourth aspect further includes a concentration meter that acquires the concentration of ammonia contained in the lubricating oil in the tank, and the pressure adjustment unit is configured to adjust the pressure of the gas in the tank based on the concentration.

[0012] In a sixth aspect of the embodiment, the lubricating oil supply device according to the first aspect includes a tank for storing the lubricating oil containing the ammonia transferred from the reciprocating engine, an air amount adjustment unit configured to adjust the amount of air sent to the lubricating oil in the tank so that the ammonia evaporates from the lubricating oil in the tank, and a fan for discharging the ammonia contained in the gas in the tank from the tank.

[0013] In a seventh aspect of the embodiment, the lubricating oil supply device described in the sixth aspect further includes a concentration meter that acquires the concentration of ammonia contained in the lubricating oil in the tank, and the air amount adjustment unit is configured to adjust the amount of air to be sent to the lubricating oil in the tank based on the concentration.

[0014] In an eighth aspect of the embodiment, the lubricating oil supplying device according to the first aspect further includes a filter that separates ammonia from the lubricating oil by passing the lubricating oil transferred from the reciprocating engine through the filter.

[0015] In a ninth aspect of the embodiment, the lubricating oil supply device described in the eighth aspect further includes a concentration meter that acquires the concentration of ammonia contained in the lubricating oil transferred from the reciprocating engine, and a flow rate adjustment unit configured to adjust the flow rate of the lubricating oil passing through the filter, and the flow rate adjustment unit is configured to adjust the amount of lubricating oil passing through the filter based on the concentration.

[0016] In a tenth aspect of the embodiment, the lubricating oil supply device according to the first aspect further includes a tank for storing the lubricating oil containing the ammonia transferred from the reciprocating engine, and a purifier for purifying the lubricating oil in the tank, and the tank is configured to transfer the lubricating oil from which the ammonia has been separated to the purifier, and to transfer the lubricating oil after being purified by the purifier to the reciprocating engine.

[0017] In an eleventh aspect of the embodiment, in the lubricating oil supply device according to the first aspect, an adjustment unit is provided that is configured to adjust at least one selected from a temperature of the lubricating oil, an air pressure in a tank that stores the lubricating oil, an amount of air sent to the lubricating oil, and a flow rate of the lubricating oil so that ammonia vaporizes from the ammonia-containing lubricating oil transferred from the reciprocating engine.

[0018] An internal combustion engine according to a twelfth aspect of the embodiment is an internal combustion engine including the lubricant oil supplying device according to any one of the first to eleventh aspects and the reciprocating engine.

[0019] An ammonia separation method according to a thirteenth aspect of the embodiment is an ammonia separation method including: transferring lubricating oil containing ammonia from a reciprocating engine driven by ammonia as fuel; separating the ammonia from the lubricating oil transferred from the reciprocating engine; and transferring the lubricating oil from which the ammonia has been separated to the reciprocating engine.

[0020] According to the embodiment, ammonia can be separated from lubricating oil.

[0021] FIG. 1 is a block diagram showing an example of the configuration of an ammonia-fueled ship including an internal combustion engine according to the first embodiment. FIG. 2 is a block diagram showing an example of the configuration of a lubricant oil supplying device provided in the internal combustion engine according to the first embodiment. FIG. 3 is a block diagram showing an example of the hardware configuration of a separation control unit provided in the lubricant oil supplying device according to the first embodiment. FIG. 4 is a block diagram showing an example of the functional configuration of a separation control unit provided in the lubricant oil supplying device according to the first embodiment. FIG. 5 is a flowchart showing an example of an ammonia separation process in the internal combustion engine according to the first embodiment. FIG. 6 is a block diagram showing an example of the configuration of a lubricant oil supplying device provided in an internal combustion engine according to the second embodiment. FIG. 7 is a block diagram showing an example of the configuration of a lubricant oil supplying device provided in an internal combustion engine according to the third embodiment. FIG. 8 is a block diagram showing an example of the configuration of a lubricant oil supplying device provided in an internal combustion engine according to the fourth embodiment. FIG. 9 is a block diagram showing an example of the configuration of a lubricant oil supplying device provided in an internal combustion engine according to a modified example of the fourth embodiment.

[0022] The embodiments will be described with reference to the drawings. Note that the scale of each part in the drawings used in the following description of the embodiments may be changed as appropriate. Also, for the sake of explanation, the drawings used in the following description of the embodiments may omit components.

[0023] 1. First Embodiment 1.1 Configuration 1.1.1 Ammonia-fueled ship Figure 1 is a block diagram showing an example of the configuration of an ammonia-fueled ship including an internal combustion engine according to the first embodiment. The ammonia-fueled ship 1 is a ship that has the function of propelling itself using ammonia as fuel. The ammonia-fueled ship 1 can switch between, for example, a mode in which it propels itself using ammonia as fuel and a mode in which it propels itself using a substance other than ammonia (for example, heavy oil) as fuel.

[0024] 1 , the ammonia-fueled ship 1 includes an internal combustion engine 2 that is driven by ammonia as fuel. The internal combustion engine 2 includes a main engine 3, a generator 4, a fuel supply device 5, and a lubricating oil supply device 6.

[0025] The main engine 3 is a reciprocating engine that functions as a primary engine for propelling the ammonia-fueled ship 1. The generator 4 is a reciprocating engine that functions as a power source for supplying electricity to the inside of the ammonia-fueled ship 1. The main engine 3 and the generator 4 are configured to be switchable between being driven by ammonia and being driven by heavy oil. That is, the main engine 3 and the generator 4 are driven by ammonia when operating in ammonia mode, and are driven by heavy oil when operating in diesel mode.

[0026] Specifically, when operating in the ammonia mode, the main engine 3 and the generator 4 are supplied with ammonia as fuel ammonia (FA) from the fuel supply device 5. When operating in the diesel mode, the main engine 3 and the generator 4 are supplied with heavy oil as fuel FO (fuel oil) from the fuel supply device 5.

[0027] Furthermore, the main engine 3 and the generator 4 are supplied with heavy oil as lubricating oil LO from a lubricating oil supply device 6. The main engine 3 and the generator 4 discharge used lubricating oil LO into the lubricating oil supply device 6.

[0028] The fuel supply system 5 is a device for supplying ammonia as fuel FA when propelling the vessel in ammonia mode, and heavy oil as fuel FO when propelling the vessel in diesel mode, to the main engine 3 and the generator 4. The portion of the fuel supply system 5 that supplies the fuel FA is also called an ammonia fuel supply system (AFSS). The AFSS includes, in addition to a piping system, various devices such as pumps and heaters for controlling the ammonia at predetermined pressures and temperatures. The AFSS is, for example, concentrated in a section different from the main engine 3, the generator 4, and the portion of the fuel supply system 5 that supplies the fuel FO.

[0029] The lubricating oil supplying device 6 is a device for supplying lubricating oil LO to the main engine 3 and the generator 4. The lubricating oil supplying device 6 is configured so that the lubricating oil LO used in the main engine 3 and the generator 4 is repeatedly used in the main engine 3 and the generator 4. The lubricating oil supplying device 6 has a function of separating ammonia contained in the lubricating oil LO.

[0030] 1.1.2 Lubricant Oil Supplying Device Figure 2 is a block diagram showing an example of the configuration of a lubricant oil supplying device provided in the internal combustion engine according to the first embodiment. For convenience of explanation, Figure 2 shows a portion of the lubricant oil supplying device 6 that supplies lubricant oil LO to the generator 4. Note that the portion of the lubricant oil supplying device 6 that supplies lubricant oil LO to the main engine 3 may have a configuration equivalent to the portion that supplies lubricant oil LO to the generator 4. The portion that supplies lubricant oil LO to the main engine 3 may be configured integrally with the portion that supplies lubricant oil LO to the generator 4.

[0031] 2, the lubricant supplying apparatus 6 includes a settling tank 10, a purifier 11, a heat exchanger 12, a fan 13, concentration meters 14 and 15, and a separation control unit 16. The lubricant supplying apparatus 6 further includes valves V1, V2, V3, V4, and V5, and a pump P1.

[0032] The settling tank 10 is a tank for storing the lubricating oil LO used in the generator 4 until it is returned to a state where it can be used again in the generator 4. In other words, the settling tank 10 has a capacity sufficient to store the lubricating oil LO used in the generator 4. The settling tank 10 is desirably made of a material that is resistant to corrosion by ammonia. For example, the settling tank 10 includes SUS (stainless steel).

[0033] The valve V1 is provided in a pipe for supplying the lubricating oil LO from the settling tank 10 to the generator 4. When the valve V1 is open, the lubricating oil LO is supplied from the settling tank 10 to the generator 4. When the valve V1 is closed, the supply of the lubricating oil LO from the settling tank 10 to the generator 4 is stopped.

[0034] The pump P1 is provided in a pipe for discharging the lubricating oil LO from the generator 4 to the settling tank 10. The pump P1 pumps out the lubricating oil accumulated in the crankcase of the generator 4 and transfers it to the settling tank 10.

[0035] The valve V2 is provided between the pump P1 and the settling tank 10 in the pipe for discharging the lubricating oil LO from the generator 4 to the settling tank 10. When the pump P1 is driven, if the valve V2 is open, the lubricating oil LO is discharged from the generator 4 to the settling tank 10. If the valve V2 is closed, the discharge of the lubricating oil LO from the generator 4 to the settling tank 10 stops.

[0036] The purifier 11 is, for example, a centrifugal separator. The purifier 11 is connected, for example, to a pipe connected to the bottom or side of the settling tank 10. The purifier 11 is configured to perform a purification process on the lubricating oil LO transferred from the settling tank 10 via the pipe. Specifically, the purifier 11 has a function of separating and removing sludge and the like contained in the lubricating oil LO by rotating the lubricating oil LO at high speed. The purifier 11 is configured to transfer the lubricating oil LO after the purification process to the settling tank 10, for example, by using a pump P1.

[0037] The valve V3 is provided in a pipe for supplying the lubricating oil LO from the settling tank 10 to the purifier 11. When the valve V3 is open, the lubricating oil LO is supplied from the settling tank 10 to the purifier 11. When the valve V3 is closed, the supply of the lubricating oil LO from the settling tank 10 to the purifier 11 is stopped.

[0038] The heat exchanger 12 is a device configured to adjust the temperature of the lubricating oil LO in the settling tank 10. The heat exchanger 12 heats the lubricating oil LO in the settling tank 10, for example, by passing steam through piping provided in the settling tank 10. The heat exchanger 12 may also cool the lubricating oil LO in the settling tank 10, for example, by passing a refrigerant through piping provided in the settling tank 10.

[0039] The valve V4 is provided in a pipe used to heat the lubricating oil LO via steam generated in the heat exchanger 12 or to cool the lubricating oil LO via a refrigerant, and functions as a temperature control valve. When the valve V4 is open, the steam or refrigerant passes through the pipe, thereby heating or cooling the lubricating oil LO in the settling tank 10. When the valve V4 is closed, the heating or cooling of the lubricating oil LO in the settling tank 10 stops.

[0040] The fan 13 is configured to exhaust the gas in the settling tank 10 to the outside of the ammonia-fueled ship 1. The gas in the settling tank 10 includes ammonia vaporized from the lubricating oil LO. In other words, the fan 13 has the function of exhausting the ammonia vaporized from the lubricating oil LO in the settling tank 10 to the outside of the ammonia-fueled ship 1.

[0041] Valve V5 is provided in a pipe connecting the settling tank 10 and the fan 13. When valve V5 is open, the gas in the settling tank 10 is discharged to the outside via the fan 13. When valve V5 is closed, the gas in the settling tank 10 is stopped from being discharged to the outside via the fan 13.

[0042] The concentration meter 14 is a sensor that detects ammonia contained in the liquid. The concentration meter 14 is disposed in a position within the settling tank 10 that is covered by the stored lubricating oil LO. The concentration meter 14 measures the concentration C1 of ammonia contained in the lubricating oil LO stored in the settling tank 10. The concentration meter 14 outputs concentration information indicating the measured ammonia concentration C1 to the separation control unit 16.

[0043] The concentration meter 15 is a sensor that detects ammonia contained in the gas. The concentration meter 15 is arranged on the outlet side of the fan 13. The concentration meter 15 measures the concentration C2 of ammonia contained in the gas that is discharged from the settling tank 10 to the outside of the ammonia-fueled ship 1 via the fan 13. The concentration meter 15 outputs concentration information indicating the measured ammonia concentration C2 to the separation control unit 16.

[0044] The separation control unit 16 is, for example, a computer device. The separation control unit 16 is configured to adjust the temperature of the lubricating oil LO in the settling tank 10 by controlling the valve V4 based on the concentrations C1 and C2, so that ammonia vaporizes from the lubricating oil LO in the settling tank 10. In other words, the heat exchanger 12, the separation control unit 16, and the valve V4 function as a temperature adjustment unit for the lubricating oil LO in the settling tank 10.

[0045] 1.1.3 Separation Control Unit FIG. 3 is a block diagram showing an example of the hardware configuration of the separation control unit included in the lubricant oil supplying device according to the first embodiment.

[0046] As shown in FIG. 3, the separation control unit 16 includes a control circuit 21, a storage 22, a communication module 23, a user interface 24, a drive 25, and a storage medium 26.

[0047] The control circuit 21 is a circuit that controls the overall components of the separation control unit 16. The control circuit 21 includes a CPU (central processing unit), a RAM (random access memory), a ROM (read only memory), etc. The CPU of the control circuit 21 controls the entire separation control unit 16 in accordance with a program stored in the ROM of the control circuit 21. The RAM of the control circuit 21 has a working area for the CPU of the control circuit 21. The ROM of the control circuit 21 stores programs and the like used by the separation control unit 16.

[0048] The storage 22 includes, for example, a hard disk drive (HDD) or a solid state drive (SSD). The storage 22 stores information used in various processes in the separation control unit 16.

[0049] The communication module 23 is a circuit used for transmitting and receiving information between the separation control unit 16 and each unit of the lubricant oil supplying device 6 other than the separation control unit 16 .

[0050] The user interface 24 is a device that manages communication between the separation control unit 16 and the user. The user interface 24 includes input devices and output devices. The input devices include, for example, a touch panel and operation buttons. The output devices include, for example, a printer, a speaker, and a display.

[0051] The drive 25 is a device for reading software stored in the storage medium 26. The drive 25 includes, for example, a CD (Compact Disk) drive or a DVD (Digital Versatile Disk) drive.

[0052] The storage medium 26 is a medium that stores software electrically, magnetically, optically, mechanically, or chemically. The storage medium 26 may store a program used by the separation control unit 16.

[0053] FIG. 4 is a block diagram showing an example of a functional configuration of the separation control unit included in the lubricant oil supplying device according to the first embodiment.

[0054] 4, the CPU of the control circuit 21 loads the program stored in the ROM of the control circuit 21 or the storage medium 26 into the RAM of the control circuit 21. The CPU of the control circuit 21 then interprets and executes the program loaded into the RAM of the control circuit 21. As a result, the separation control unit 16 functions as a computer including an acquisition unit 31, a sequence control unit 32, and a transfer control unit 33. In addition, a sequence table 34 is stored in the storage 22.

[0055] The acquisition unit 31 is a functional block that acquires concentration information measured by the concentration meters 14 and 15. The acquisition unit 31 outputs the acquired concentration information to the sequence control unit 32.

[0056] The sequence control unit 32 is a functional block that controls the execution of the separation sequence. The separation sequence in the first embodiment is an optimal temperature profile for efficiently separating ammonia from the lubricant oil LO by controlling the temperature of the lubricant oil LO using the heat exchanger 12. Specifically, the separation sequence may be information that specifies the change in temperature of the lubricant oil LO over time.

[0057] The sequence control unit 32 determines whether the ammonia concentration C1 contained in the lubricating oil LO in the settling tank 10 is less than a threshold value TH1. The threshold value TH1 is an ammonia concentration at which the lubricating oil LO is deemed not to deteriorate. The threshold value TH1 may be an ammonia concentration at which the lubricating oil LO is deemed not to have a negative impact on the crew during maintenance of the generator 4 or the purifier 11. The threshold value TH1 may be an ammonia concentration at which the ammonia concentration is deemed not to affect the deterioration of the generator 4 or the purifier 11. If the concentration C1 is less than the threshold value TH1, the sequence control unit 32 determines that an ammonia separation sequence is not necessary. If the concentration C1 is equal to or greater than the threshold value TH1, the sequence control unit 32 determines that an ammonia separation sequence is necessary and selects a separation sequence corresponding to the concentration C1 from the sequence table 34. The sequence table 34 pre-stores a plurality of separation sequences, each corresponding to an ammonia concentration in the lubricating oil LO. The sequence control unit 32 executes the selected separation sequence by controlling the state of the valve V4.

[0058] The sequence control unit 32 also determines whether the ammonia concentration C2 of the gas discharged from the settling tank 10 is less than a threshold value TH2. The threshold value TH2 is a value determined based on the ammonia concentration in the atmosphere that may have adverse effects on the human body, and is, for example, 25 ppm. If the concentration C2 is equal to or greater than the threshold value TH2, the sequence control unit 32 determines that the separation sequence currently being executed needs to be relaxed. Here, relaxation of the separation sequence refers to changing the separation sequence so as to suppress the amount of ammonia vaporized. Relaxation of the separation sequence may include pausing the separation sequence. If the concentration C2 is less than the threshold value TH2, the sequence control unit 32 determines that relaxation of the separation sequence currently being executed is unnecessary. After the separation sequence ends, the sequence control unit 32 outputs a separation sequence end notification to the transfer control unit 33.

[0059] The transfer control unit 33 is a functional block that controls the transfer of the lubricating oil LO in the lubricating oil supply device 6. The transfer control unit 33 transfers the lubricating oil LO from the settling tank 10 to the generator 4 by opening valve V1. The transfer control unit 33 transfers the lubricating oil LO from the generator 4 or the purifier 11 to the settling tank 10 by opening valve V2 and driving pump P1. The transfer control unit 33 transfers the lubricating oil LO from the settling tank 10 to the purifier 11 by opening valve V3. The transfer control unit 33 exhausts the gas in the settling tank 10 to the outside of the ammonia-fueled ship 1 via the fan 13 by opening valve V5.

[0060] 1.2 Operation Next, the operation of the internal combustion engine according to the embodiment will be described.

[0061] FIG. 5 is a flowchart showing an example of an ammonia separation process in the internal combustion engine according to the embodiment.

[0062] When a predetermined amount of used lubricating oil LO is accumulated in the crankcase of the generator 4 (start), the transfer control unit 33 transfers the used lubricating oil LO from the generator 4 into the settling tank 10 (S11). Note that prior to the processing of S11, the generator 4 is stopped.

[0063] The acquisition unit 31 acquires the concentration C1 of ammonia contained in the used lubricating oil LO transferred into the settling tank 10 in the process of S11 (S12).

[0064] The sequence controller 32 determines whether the concentration C1 obtained in the process of S12 is less than the threshold value TH1 (S13).

[0065] If the ammonia concentration C1 contained in the lubricating oil LO in the settling tank 10 is equal to or greater than the threshold value TH1 (S13; no), the sequence control unit 32 selects a separation sequence based on the concentration C1 (S14). Specifically, the sequence control unit 32 selects a separation sequence corresponding to the concentration C1 from a plurality of separation sequences stored in the sequence table 34.

[0066] The sequence control unit 32 controls the state of the valve V4 to start the separation sequence selected in the process of S14 (S15).

[0067] After the process of S15, the acquisition unit 31 acquires the concentration C2 of ammonia contained in the gas discharged from the settling tank 10 via the fan 13 while the separation sequence is being executed (S16).

[0068] The sequence controller 32 determines whether the concentration C2 obtained in the process of S16 is equal to or greater than a threshold value TH2 (S17).

[0069] If the concentration C2 of ammonia contained in the gas discharged from the settling tank 10 is equal to or greater than the threshold value TH2 (S17; yes), the sequence control unit 32 eases the separation sequence (S18).

[0070] If the concentration C2 of ammonia contained in the gas discharged from the settling tank 10 is less than the threshold value TH2 (S17; no), or after processing S18, the sequence control unit 32 determines whether the separation sequence started in processing S15 has ended (S19).

[0071] If the separation sequence is being executed (S19; no), the acquisition unit 31 acquires the ammonia concentration C2 contained in the gas discharged from the settling tank 10 via the fan 13 (S16). Then, the sequence control unit 32 determines whether the concentration C2 acquired in the process of S16 is equal to or greater than the threshold value TH2 (S17). In this way, the process of measuring the concentration C2 and the process of determining whether the concentration C2 is equal to or greater than the threshold value are repeated until the separation sequence is completed.

[0072] When the separation sequence is completed (S19; yes), the acquisition unit 31 acquires the ammonia concentration C1 contained in the lubricating oil LO in the settling tank 10 (S12). Then, the sequence control unit 32 determines whether the concentration C1 acquired in the process of S12 is less than the threshold value TH1 (S13). In this manner, the processes of S12 to S19 are repeated until the concentration C1 becomes less than the threshold value TH1.

[0073] If the concentration C1 of ammonia contained in the lubricating oil LO in the settling tank 10 is less than the threshold value TH1 (S13; yes), the transfer control unit 33 transfers the lubricating oil LO in the settling tank 10 to the purifier 11 (S20).

[0074] The purifier 11 performs a purification process on the lubricating oil LO transferred into the purifier 11 in the process of S20 (S21), thereby removing solid impurities such as sludge contained in the lubricating oil LO.

[0075] After the process of S21, the transfer control unit 33 transfers the lubricating oil LO in the purifier 11 into the settling tank 10 (S22).

[0076] After the process of S22, the transfer control unit 33 transfers the lubricating oil LO in the settling tank 10 to the generator 4 (S23).

[0077] After the process of S23, the ammonia separation process ends (end).

[0078] 1.3 Effects of the First Embodiment According to the first embodiment, the lubricating oil supplying device 6 is configured to transfer ammonia-containing lubricating oil LO from the generator 4 driven by ammonia as fuel, separate the ammonia from the ammonia-containing lubricating oil LO, and transfer the lubricating oil LO from which the ammonia has been separated to the generator 4. Specifically, the lubricating oil supplying device 6 includes a settling tank 10, a heat exchanger 12, and a fan 13. The settling tank 10 stores the ammonia-containing lubricating oil LO transferred from the generator 4. The heat exchanger 12 is configured to adjust the temperature of the lubricating oil LO in the settling tank 10 so that the ammonia vaporizes from the lubricating oil LO in the settling tank 10. The fan 13 discharges ammonia contained in the gas in the settling tank 10 from the settling tank 10. As a result, the ammonia is vaporized by heating the lubricating oil LO in the settling tank 10, and the vaporized ammonia can be discharged overboard via the fan 13. Therefore, the ammonia concentration in the lubricating oil LO reused in the generator 4 can be reduced to a level where the lubricating oil LO is not significantly deteriorated due to ammonia, thereby improving the utilization efficiency of the lubricating oil LO.

[0079] The lubricating oil supplying device 6 further includes concentration meters 14 and 15 and a separation control unit 16. The separation control unit 16 controls the amount of heating by the heat exchanger 12 based on the ammonia concentration C1 in the lubricating oil LO measured by the concentration meter 14 and the ammonia concentration C2 in the exhaust gas measured by the concentration meter 15. Specifically, the sequence control unit 32 selects a separation sequence that specifies a temperature profile for the lubricating oil LO based on the concentration C1. This makes it possible to apply an optimal temperature profile depending on the ammonia concentration C1 dissolved in the lubricating oil LO. This reduces the cost required for ammonia separation. The sequence control unit 32 also relaxes the separation sequence based on the concentration C2. This makes it possible to prevent excessive ammonia from being discharged overboard. This makes it possible to execute an optimal separation sequence while complying with regulations regarding ammonia discharged overboard.

[0080] The lubricating oil supply device 6 further includes a purifier 11. After the concentration C1 becomes less than the threshold value TH1, the transfer control unit 33 transfers the lubricating oil LO in the settling tank 10 to the purifier 11, and transfers the lubricating oil purified by the purifier 11 from the settling tank 10 to the generator 4. This makes it possible to suppress the concentration of ammonia contained in the lubricating oil LO transferred to the purifier 11 and the generator 4 to be less than the threshold value TH1. Therefore, when servicing the generator 4 and the purifier 11, it is possible to reduce the risk of injury to crew members due to ammonia contained in the lubricating oil remaining in the generator 4 and the purifier 11, and to reduce the possibility of the generator 4 and the purifier 11 being deteriorated by ammonia contained in the lubricating oil.

[0081] 2. Second Embodiment Next, a second embodiment will be described. The second embodiment differs from the first embodiment in that ammonia is separated from the lubricating oil LO by adjusting the pressure in the settling tank 10. The following mainly describes configurations and operations that differ from the first embodiment. Descriptions of configurations and operations that are equivalent to those of the first embodiment will be omitted as appropriate.

[0082] 2.1 Lubricating Oil Supply Device Fig. 6 is a block diagram showing an example of the configuration of a lubricating oil supply device provided in an internal combustion engine according to the second embodiment. Fig. 6 corresponds to Fig. 2 in the first embodiment.

[0083] 6, the lubricant oil supplying apparatus 6 according to the second embodiment includes a settling tank 10, a purifier 11, a fan 13, concentration meters 14 and 15, a separation control unit 16, and a vacuum pump 17. The lubricant oil supplying apparatus 6 further includes valves V1, V2, V3, V6, and V7, and a pump P1. The configurations of the settling tank 10, the purifier 11, the fan 13, the concentration meters 14 and 15, the valves V1, V2, and V3, and the pump P1 are the same as those in the first embodiment.

[0084] The vacuum pump 17 is a device that adjusts the pressure of the gas inside the settling tank 10. The vacuum pump 17 draws out the gas inside the settling tank 10, thereby creating a vacuum inside the settling tank 10 (i.e., reducing the pressure). The gas drawn out of the settling tank 10 by the vacuum pump 17 may contain ammonia vaporized from the lubricating oil LO. To prevent the ammonia contained in the gas drawn out of the settling tank 10 by the vacuum pump 17 from affecting the crew, the vacuum pump 17 is provided, for example, in an area different from other devices of the lubricating oil supply apparatus 6. The example in FIG. 6 shows a case where the vacuum pump 17 is isolated and disposed in the exhaust chamber ER.

[0085] The valve V6 is provided in a pipe connecting the settling tank 10 and the vacuum pump 17 in the exhaust chamber ER. The valve V6 is configured to open and close in conjunction with the driving state of the vacuum pump 17. That is, when the vacuum pump 17 discharges the gas in the settling tank 10 into the exhaust chamber ER, the valve V6 is in an open state. When the vacuum pump 17 stops discharging the gas in the settling tank 10 into the exhaust chamber ER, the valve V6 is in a closed state.

[0086] The valve V7 is provided in a pipe connecting the exhaust chamber ER and the fan 13. When the valve V7 is open, the gas in the exhaust chamber ER is discharged to the outside via the fan 13. When the valve V7 is closed, the gas in the exhaust chamber ER is stopped from being discharged to the outside via the fan 13.

[0087] The separation control unit 16 is, for example, a computer device. The separation control unit 16 is configured to adjust the pressure of the gas in the settling tank 10 by controlling the valve V6 based on the concentrations C1 and C2, so that ammonia vaporizes from the lubricating oil LO in the settling tank 10. In other words, the vacuum pump 17, the separation control unit 16, and the valve V6 function as a pressure adjustment unit for the gas in the settling tank 10.

[0088] In this case, the sequence control unit 32 of the separation control unit 16 controls the execution of a separation sequence for efficiently separating ammonia from the lubricating oil LO by controlling the pressure of the gas in the settling tank 10 using the vacuum pump 17. That is, the separation sequence in the second embodiment is an optimal pressure profile for efficiently separating ammonia from the lubricating oil LO by controlling the pressure of the gas in the settling tank 10 using the vacuum pump 17. Specifically, the separation sequence may be information specifying the change over time in the pressure of the gas in the settling tank 10.

[0089] The sequence control unit 32 determines whether the concentration C1 of ammonia contained in the lubricating oil LO in the settling tank 10 is less than a threshold value TH1. If the concentration C1 is less than the threshold value TH1, the sequence control unit 32 determines that an ammonia separation sequence is unnecessary. If the concentration C1 is equal to or greater than the threshold value TH1, the sequence control unit 32 determines that an ammonia separation sequence is necessary, and selects a separation sequence corresponding to the concentration C1 from the sequence table 34. The sequence control unit 32 executes the selected separation sequence by controlling the state of the valve V6.

[0090] The sequence control unit 32 also determines whether the concentration of ammonia discharged from the exhaust chamber ER is less than a threshold value TH2. If the concentration C2 is equal to or greater than the threshold value TH2, the sequence control unit 32 determines that the separation sequence currently being executed needs to be relaxed. If the concentration C2 is less than the threshold value TH2, the sequence control unit 32 determines that the separation sequence currently being executed does not need to be relaxed.

[0091] 2.2 Effects of the Second Embodiment According to the second embodiment, the lubricating oil supply device 6 includes a settling tank 10, a vacuum pump 17, and a fan 13. The vacuum pump 17 is configured to adjust the pressure of the gas in the settling tank 10 so that ammonia vaporizes from the lubricating oil LO in the settling tank 10. This allows the settling tank 10 to be brought close to a vacuum state, thereby vaporizing the ammonia, and the vaporized ammonia can be discharged overboard via the fan 13. As a result, the ammonia concentration in the lubricating oil LO reused in the generator 4 can be reduced to a level that does not significantly deteriorate the lubricating oil LO due to ammonia. This increases the utilization efficiency of the lubricating oil LO.

[0092] The lubricating oil supply device 6 further includes concentration meters 14 and 15 and a separation control unit 16. The separation control unit 16 controls the amount of gas suctioned by the vacuum pump 17 based on the ammonia concentration C1 in the lubricating oil LO measured by the concentration meter 14 and the ammonia concentration C2 in the discharged gas measured by the concentration meter 15. Specifically, the sequence control unit 32 selects a separation sequence that specifies the pressure profile in the settling tank 10 based on the concentration C1. This makes it possible to apply an optimal pressure profile depending on the ammonia concentration C1 dissolved in the lubricating oil LO. This reduces the cost required for ammonia separation. The sequence control unit 32 also relaxes the separation sequence based on the concentration C2. This makes it possible to prevent excessive ammonia from being discharged overboard. This makes it possible to execute an optimal separation sequence while complying with regulations regarding ammonia discharged overboard.

[0093] 3. Third Embodiment Next, a third embodiment will be described. The third embodiment differs from the first embodiment in that ammonia is separated from the lubricating oil LO by injecting air into the lubricating oil LO. The following mainly describes configurations and operations that differ from the first embodiment. Descriptions of configurations and operations that are equivalent to those of the first embodiment will be omitted as appropriate.

[0094] 3.1 Lubricating Oil Supply Device Fig. 7 is a block diagram showing an example of the configuration of a lubricating oil supply device provided in an internal combustion engine according to Embodiment 3. Fig. 7 corresponds to Fig. 2 in the first embodiment.

[0095] 7, the lubricating oil supplying apparatus 6 according to the third embodiment includes a settling tank 10, a purifier 11, a fan 13, concentration meters 14 and 15, a separation control unit 16, and an air ejector 18. The lubricating oil supplying apparatus 6 further includes valves V1, V2, V3, V5, and V8, and a pump P1. The configurations of the settling tank 10, the purifier 11, the fan 13, the concentration meters 14 and 15, the valves V1, V2, and V3, and the pump P1 are the same as those in the first embodiment.

[0096] The air ejector 18 is a device that adjusts the amount of air that is sent into the lubricating oil LO in the settling tank 10. The air ejector 18 sends air into the lubricating oil LO in the settling tank 10, thereby promoting the evaporation of ammonia contained in the lubricating oil LO.

[0097] The valve V8 is provided in a pipe connecting the settling tank 10 and the air jet 18. When the valve V8 is open, the air jet 18 sends air into the lubricating oil LO in the settling tank 10. When the valve V8 is closed, the air jet 18 stops sending air into the lubricating oil LO in the settling tank 10.

[0098] The separation control unit 16 is, for example, a computer device. The separation control unit 16 is configured to adjust the amount of air fed into the lubricating oil LO in the settling tank 10 by controlling the valve V8 based on the concentrations C1 and C2, so that ammonia vaporizes from the lubricating oil LO in the settling tank 10. In other words, the air ejector 18, the separation control unit 16, and the valve V8 function as an air amount adjustment unit that adjusts the amount of air fed into the lubricating oil LO in the settling tank 10.

[0099] In this case, the sequence control unit 32 of the separation control unit 16 controls the execution of a separation sequence for efficiently separating ammonia from the lubricating oil LO by controlling the amount of air fed into the lubricating oil LO using the air ejector 18. That is, the separation sequence in the third embodiment is an optimal air amount profile for efficiently separating ammonia from the lubricating oil LO by controlling the amount of air fed into the lubricating oil LO using the air ejector 18. Specifically, the separation sequence may be information specifying the change over time in the amount of air fed into the lubricating oil LO.

[0100] The sequence control unit 32 determines whether the concentration C1 of ammonia contained in the lubricating oil LO in the settling tank 10 is less than a threshold value TH1. If the concentration C1 is less than the threshold value TH1, the sequence control unit 32 determines that an ammonia separation sequence is unnecessary. If the concentration C1 is equal to or greater than the threshold value TH1, the sequence control unit 32 determines that an ammonia separation sequence is necessary, and selects a separation sequence corresponding to the concentration C1 from the sequence table 34. The sequence control unit 32 executes the selected separation sequence by controlling the state of the valve V8.

[0101] The sequence control unit 32 also determines whether the concentration of ammonia discharged from the settling tank 10 is less than a threshold value TH2. If the concentration C2 is equal to or greater than the threshold value TH2, the sequence control unit 32 determines that the separation sequence currently being executed needs to be relaxed. If the concentration C2 is less than the threshold value TH2, the sequence control unit 32 determines that the separation sequence currently being executed does not need to be relaxed.

[0102] 3.2 Effects of the Third Embodiment According to the third embodiment, the lubricating oil supplying device 6 includes a settling tank 10, an air ejector 18, and a fan 13. The air ejector 18 is configured to adjust the amount of air sent to the lubricating oil LO in the settling tank 10 so that ammonia vaporizes from the lubricating oil LO in the settling tank 10. This allows the ammonia to be vaporized by stirring the lubricating oil LO, and the vaporized ammonia can be discharged overboard via the fan 13. Therefore, the ammonia concentration in the lubricating oil LO reused in the generator 4 can be reduced to a level that does not significantly deteriorate the lubricating oil LO due to ammonia. Therefore, the utilization efficiency of the lubricating oil LO can be improved.

[0103] The lubricating oil supply device 6 further includes concentration meters 14 and 15 and a separation control unit 16. The separation control unit 16 controls the amount of air sent by the air ejector 18 based on the ammonia concentration C1 in the lubricating oil LO measured by the concentration meter 14 and the ammonia concentration C2 in the exhaust gas measured by the concentration meter 15. Specifically, the sequence control unit 32 selects a separation sequence that specifies the air amount profile to be sent into the lubricating oil LO based on the concentration C1. This makes it possible to apply an optimal air amount profile depending on the ammonia concentration C1 dissolved in the lubricating oil LO. This reduces the cost required for ammonia separation. The sequence control unit 32 also relaxes the separation sequence based on the concentration C2. This makes it possible to prevent excessive ammonia from being discharged overboard. This makes it possible to execute an optimal separation sequence while complying with regulations regarding ammonia discharged overboard.

[0104] 4. Fourth Embodiment Next, a fourth embodiment will be described. The fourth embodiment differs from the first embodiment in that ammonia is separated from the lubricating oil LO by passing the lubricating oil LO through a filter. The following mainly describes configurations and operations that differ from the first embodiment. Descriptions of configurations and operations that are equivalent to those of the first embodiment will be omitted as appropriate.

[0105] 4.1 Lubricating Oil Supplying Device Fig. 8 is a block diagram showing an example of the configuration of a lubricating oil supplying device provided in an internal combustion engine according to Embodiment 4. Fig. 8 corresponds to Fig. 2 in the first embodiment.

[0106] 8, the lubricant oil supplying apparatus 6 according to the fourth embodiment includes a settling tank 10, a purifier 11, a concentration meter 14, a separation control unit 16, and a filter 19. The lubricant oil supplying apparatus 6 further includes valves V1, V2, and V3, and pumps P1 and P2. The configurations of the settling tank 10, the purifier 11, the concentration meter 14, the valves V1, V2, and V3, and the pump P1 are the same as those in the first embodiment.

[0107] The filter 19 has a function of separating dissolved ammonia from the lubricating oil LO when the lubricating oil LO passes through the filter 19. The filter 19 is, for example, a zeolite filter.

[0108] The pump P2 is provided in a pipe connecting the settling tank 10 and the filter 19. The pump P2 has a function of adjusting the flow rate of the lubricating oil LO that passes through the filter 19.

[0109] The separation control unit 16 is, for example, a computer device. The separation control unit 16 is configured to adjust the flow rate of the lubricating oil LO passing through the filter 19 by controlling the pump P2 based on the concentration C1, so that ammonia is removed from the lubricating oil LO in the settling tank 10. In other words, the filter 19, the separation control unit 16, and the pump P2 function as a flow rate adjustment unit that adjusts the flow rate of the ammonia removed by the filter 19.

[0110] In this case, the sequence control unit 32 of the separation control unit 16 controls the execution of a separation sequence for efficiently separating ammonia from the lubricating oil LO by controlling the flow rate of the lubricating oil LO passing through the filter 19. That is, the separation sequence in the fourth embodiment is an optimal flow rate profile for efficiently separating ammonia from the lubricating oil LO by controlling the flow rate of the lubricating oil LO passing through the filter 19. Specifically, the separation sequence may be information specifying the change over time in the flow rate of the lubricating oil LO passing through the filter 19.

[0111] The sequence control unit 32 determines whether the concentration C1 of ammonia contained in the lubricating oil LO in the settling tank 10 is less than a threshold value TH1. If the concentration C1 is less than the threshold value TH1, the sequence control unit 32 determines that an ammonia separation sequence is unnecessary. If the concentration C1 is equal to or greater than the threshold value TH1, the sequence control unit 32 determines that an ammonia separation sequence is necessary, and selects a separation sequence corresponding to the concentration C1 from the sequence table 34. The sequence control unit 32 executes the selected separation sequence by controlling the pump P2.

[0112] 4.2 Effects of the Fourth Embodiment According to the fourth embodiment, the lubricant oil supplying device 6 includes a settling tank 10, a filter 19, and a pump P2. The pump P2 is configured to adjust the flow rate of the lubricant oil LO passing through the filter 19 so that ammonia is separated from the lubricant oil LO in the settling tank 10. This allows the ammonia contained in the lubricant oil LO to be adsorbed by the filter 19. Therefore, the ammonia concentration in the lubricant oil LO reused in the generator 4 can be reduced to a level where the lubricant oil LO is not significantly deteriorated due to ammonia. Therefore, the utilization efficiency of the lubricant oil LO can be improved.

[0113] The lubricant supplying device 6 further includes a concentration meter 14 and a separation control unit 16. The separation control unit 16 controls the flow rate of the lubricant LO passed through the filter 19 by the pump P2 based on the ammonia concentration C1 in the lubricant LO measured by the concentration meter 14. Specifically, the sequence control unit 32 selects a separation sequence that specifies the flow rate profile of the lubricant LO passed through the filter 19 based on the concentration C1. This makes it possible to apply an optimal flow rate profile depending on the ammonia concentration C1 dissolved in the lubricant LO. This reduces the cost required for ammonia separation.

[0114] 5. Modifications, etc. Various modifications can be applied to the above-described embodiments.

[0115] In the fourth embodiment, the lubricating oil LO is stored in the settling tank 10 and then passes through the filter 19. However, the present invention is not limited to this. FIG. 9 is a block diagram showing an example of the configuration of a lubricating oil supplying device provided in an internal combustion engine according to a modified example of the fourth embodiment. FIG. 9 corresponds to FIG. 8 in the fourth embodiment. As shown in FIG. 9 , the lubricating oil supplying device 6 only needs to include the filter 19 and the pump P3, and does not necessarily need to include a settling tank. The pump P3 is provided in a pipe connecting the generator 4 and the filter 19. The pump P2 has a function of adjusting the flow rate of the lubricating oil LO passing through the filter 19. This allows the lubricating oil LO to pass through the filter 19 without being stored in the settling tank. This allows the area occupied by the lubricating oil supplying device 6 to be reduced, making it easier to apply to small boats.

[0116] In the first, second, third, and fourth embodiments, ammonia is separated from the lubricating oil LO by adjusting the temperature of the lubricating oil LO in the settling tank 10, adjusting the pressure in the settling tank 10, injecting air into the lubricating oil LO in the settling tank 10, and passing the lubricating oil LO through a filter. However, this is not limited to this. For example, ammonia may be separated from the lubricating oil LO by any combination of the first, second, third, and fourth embodiments. In this case, the sequence control unit 32 may control the execution of a separation sequence that optimally controls any combination of the temperature of the lubricating oil LO in the settling tank 10, the pressure in the settling tank 10, the amount of air injected into the lubricating oil LO, and the flow rate of the lubricating oil LO passing through the filter, based on the concentrations C1 and C2. This prevents deterioration of the lubricating oil LO and equipment damage, and reduces operating costs.

[0117] In the above first, second, third, and fourth embodiments, the lubricating oil supplying device 6 is described as being provided independently of the reciprocating engines such as the main engine 3 and the generator 4, but this is not limiting. For example, the lubricating oil supplying device 6 may be integrated with the reciprocating engines such as the main engine 3 and the generator 4.

[0118] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention.

[0119] 1...ammonia-fueled ship, 2...internal combustion engine, 3...main engine, 4...generator, 5...fuel supply device, 6...lubricating oil supply device, 10...settling tank, 11...purifier, 12...heat exchanger, 13...fan, 14, 15...concentration meter, 16...separation control unit, 17...vacuum pump, 18...air blower, 19...filter, 21...control circuit, 22...storage, 23...communication module, 24...user interface, 25...drive, 26...storage medium, 31...acquisition unit, 32...sequence control unit, 33...transfer control unit, 34...sequence table, P1, P2, P3...pump, V1, V2, V3, V4, V5, V6, V7, V8...valve, ER...exhaust chamber.

Claims

1. A lubricating oil supply device configured to transfer lubricating oil containing ammonia from a reciprocating engine driven by ammonia as fuel, separate the ammonia from the lubricating oil containing ammonia, and transfer the lubricating oil from which the ammonia has been separated to the reciprocating engine.

2. A lubricating oil supply device according to claim 1, comprising: a tank that stores the lubricating oil containing ammonia transferred from the reciprocating engine; a temperature adjustment unit configured to adjust the temperature of the lubricating oil in the tank so that the ammonia evaporates from the lubricating oil in the tank; and a fan that exhausts the ammonia contained in the gas in the tank from the tank.

3. The lubricating oil supply device according to claim 2, further comprising a concentration meter that acquires the concentration of ammonia contained in the lubricating oil in the tank, and the temperature adjustment unit is configured to adjust the temperature of the lubricating oil in the tank based on the concentration.

4. A lubricating oil supply device according to claim 1, comprising: a tank for storing the lubricating oil containing ammonia transferred from the reciprocating engine; a pressure adjusting unit configured to adjust the pressure of gas in the tank so that ammonia evaporates from the lubricating oil in the tank; and a fan for discharging the ammonia contained in the gas in the tank.

5. The lubricating oil supply device according to claim 4, further comprising a concentration meter that acquires the concentration of ammonia contained in the lubricating oil in the tank, and the pressure adjustment unit is configured to adjust the pressure of the gas in the tank based on the concentration.

6. A lubricating oil supply device according to claim 1, comprising: a tank for storing the lubricating oil containing ammonia transferred from the reciprocating engine; an air amount adjustment unit configured to adjust the amount of air to be fed into the lubricating oil in the tank so that the ammonia is vaporized from the lubricating oil in the tank; and a fan for discharging the ammonia contained in the gas in the tank from the tank.

7. A lubricating oil supply device according to claim 6, further comprising a concentration meter that acquires the concentration of ammonia contained in the lubricating oil in the tank, and the air amount adjustment unit is configured to adjust the amount of air to be fed into the lubricating oil in the tank based on the concentration.

8. The lubricating oil supply device according to claim 1, further comprising a filter that separates ammonia from the lubricating oil transferred from the reciprocating engine by passing the lubricating oil through the filter.

9. A lubricating oil supply device as described in claim 8, further comprising: a concentration meter that acquires the concentration of ammonia contained in the lubricating oil transferred from the reciprocating engine; and a flow rate adjustment unit configured to adjust the flow rate of the lubricating oil that passes through the filter, wherein the flow rate adjustment unit is configured to adjust the flow rate of the lubricating oil that passes through the filter based on the concentration.

10. A lubricating oil supply device according to claim 1, further comprising: a tank for storing the lubricating oil containing the ammonia transferred from the reciprocating engine; and a purifier for purifying the lubricating oil in the tank, wherein the tank is configured to transfer the lubricating oil from which the ammonia has been separated to the purifier, and to transfer the lubricating oil after being purified by the purifier to the reciprocating engine.

11. The lubricating oil supply device according to claim 1, further comprising an adjusting unit configured to adjust at least one selected from the temperature of the lubricating oil, the pressure of air in a tank that stores the lubricating oil, the amount of air sent into the lubricating oil, and the flow rate of the lubricating oil, so that ammonia vaporizes from the lubricating oil that contains ammonia and is transferred from the reciprocating engine.

12. An internal combustion engine comprising: a lubricating oil supply device according to any one of claims 1 to 11; and the reciprocating engine.

13. A method for separating ammonia, comprising: transferring lubricating oil containing ammonia from a reciprocating engine that is driven by ammonia as fuel; separating the ammonia from the lubricating oil transferred from the reciprocating engine; and transferring the lubricating oil from which the ammonia has been separated to the reciprocating engine.

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