JP2022100937A - Dual fuel engine system - Google Patents

Abstract

To reduce combustion abnormality in a dual fuel engine using at least one of ammonia and hydrogen.SOLUTION: A system 100 comprises: an engine 10 using at least two fuels that are selected from a group consisting of ammonia, hydrogen, natural gas and liquid fuel and comprise at least one of ammonia and hydrogen; and a control device 50 that determines whether or not combustion of the engine 10 is abnormal during operation using at least one of ammonia and hydrogen, and when determining that the combustion of the engine 10 is abnormal, controls the engine 10 in such a manner that the fuel combination or the fuel combination ratio is changed by adding at least one of ammonia, hydrogen, natural gas and liquid fuel.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a dual fuel engine system.

Conventionally, a dual fuel engine using a plurality of fuels is known. For example, Patent Document 1 describes a diesel mode that uses a liquid fuel such as heavy oil, a gas mode that mainly uses a gaseous fuel such as natural gas, and an assist mode that uses both the liquid fuel and the gaseous fuel described above. It discloses a dual fuel engine equipped with. This engine normally operates in gas mode. During operation, when the load of the engine on the rotational speed exceeds the threshold value, the engine starts the assist mode. After that, when the load of the engine drops below the threshold value, the engine returns to the gas mode.

Japanese Unexamined Patent Publication No. 2012-38953

In recent years, in order to protect the global environment, there is a general demand for reduction of carbon dioxide emissions. Ammonia and hydrogen are known as fuels that do not emit carbon dioxide. Therefore, it is desirable that these fuels are also used in dual fuel engines. However, in an engine using these fuels, combustion abnormalities such as knocking, misfire, or ammonia slip can be a problem.

In view of the above problems, it is an object of the present disclosure to provide a dual fuel engine system capable of reducing combustion abnormalities in a dual fuel engine using at least one of ammonia and hydrogen.

One aspect of the present disclosure is a dual fuel engine selected from the group consisting of ammonia, hydrogen, natural gas and liquid fuels and using at least two fuels comprising at least one of ammonia or hydrogen, and ammonia or hydrogen. During operation using at least one of the dual fuel engines, it is determined whether the dual fuel engine is abnormally burned, and if the dual fuel engine is determined to be abnormally burned, then of ammonia, hydrogen, natural gas or liquid fuel. A dual fuel engine system comprising a control device that controls the dual fuel engine so as to add at least one to change the fuel composition or the fuel composition ratio.

The controller will determine if the dual fuel engine has misfired or ammonia slip while operating with ammonia and will add liquid fuel if it is determined to have misfired or ammonia slip. In addition, the dual fuel engine may be controlled.

Alternatively, the controller determines if the dual fuel engine has misfired or ammonia slip while operating with ammonia, and if it is determined that a misfire or ammonia slip has occurred, hydrogen is released. The dual fuel engine may be controlled to add.

In the above case, the control device determines whether or not a misfire or ammonia slip has occurred in the dual fuel engine after adding hydrogen, and if it is determined that a misfire or ammonia slip has occurred, the liquid fuel is used. The dual fuel engine may be controlled to add.

According to the present disclosure, combustion anomalies can be reduced in dual fuel engines that use at least one of ammonia and hydrogen.

FIG. 1 is a schematic cross-sectional view of a dual fuel engine system according to an embodiment. FIG. 2 shows the pattern of fuel used in the dual fuel engine system of FIG. FIG. 3 is a flowchart showing an example of the operation of the dual fuel engine system of FIG. FIG. 4 is a flowchart showing another example of the operation of the dual fuel engine system of FIG. FIG. 5 shows the operation following FIG.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The dimensions, materials, specific numerical values, etc. shown in the embodiments are merely examples for facilitating understanding, and are not intended to limit the present disclosure unless otherwise specified. In the present specification and the drawings, elements having substantially the same function and configuration are designated by the same reference numerals, and duplicate description will be omitted. In addition, elements not directly related to the present disclosure are not shown.

FIG. 1 is a schematic cross-sectional view of the dual fuel engine system 100 according to the embodiment. In this embodiment, the dual fuel engine system (hereinafter, also simply referred to as "system" in the present disclosure) 100 is applied to a ship. The system 100 includes, for example, a dual fuel engine (hereinafter, also simply referred to as an “engine” in the present disclosure) 10, a first tank T1, a second tank T2, a third tank T3, a control device 50, and the like. To prepare for. In FIG. 1, the solid line connecting the engine 10 and each tank indicates the fuel flow, and the broken line connecting the control device 50 and each component indicates communication between them. In this embodiment, the engine 10 is a two-stroke engine. In another embodiment, the engine 10 may be a 4-stroke engine.

The engine 10 includes, for example, a cylinder 1, a piston 2, a piston rod 3, a cylinder cover 4, an exhaust valve box 5, an exhaust valve 6, a drive device 7, a scavenging reservoir 8, a cylinder jacket 9, and the like. It has a first injection port R1, a second injection port R2, a pressure sensor S1, a knock sensor S2, and an ammonia sensor S3.

The piston 2 is arranged in the cylinder 1. The piston 2 reciprocates in the cylinder 1. The first end portion (upper end portion in FIG. 1) of the piston rod 3 is connected to the piston 2. A crosshead (not shown) is connected to the second end portion (lower end portion in FIG. 1) of the piston rod 3. The crosshead is connected to the crankshaft via a connecting rod or the like (not shown). The reciprocating movement of the piston 2 is converted into the rotational movement of the crankshaft.

The cylinder cover 4 closes the first end portion (upper end portion in FIG. 1) of the cylinder 1. A part of the exhaust valve box 5 is inserted into the cylinder cover 4 and faces the piston 2. The combustion chamber 11 is defined by a cylinder 1, a cylinder cover 4, an exhaust valve box 5, and a piston 2. The exhaust valve box 5 includes an exhaust port 5a. The exhaust port 5a opens into the combustion chamber 11.

The cylinder cover 4 is provided with a first injection port R1 and a second injection port R2. From the first injection port R1, gaseous fuel (at least one of ammonia, hydrogen, or natural gas) is injected into the combustion chamber 11. Liquid fuel is injected into the combustion chamber 11 from the second injection port R2 (details of the fuel will be described later).

The pressure sensor S1 is provided on the cylinder cover 4. The pressure sensor S1 measures the pressure in the combustion chamber 11. The pressure sensor S1 is connected to the control device 50 by wire or wirelessly so as to be communicable with the control device 50, and transmits the measured pressure data to the control device 50.

The knock sensor S2 is provided on the cylinder cover 4. For example, the knock sensor S2 is a vibration sensor and measures the vibration of the cylinder cover 4. The knock sensor S2 can detect the vibration of the cylinder cover 4 generated by knocking. The knock sensor S2 is connected to the control device 50 by wire or wirelessly so as to be communicable with the control device 50, and transmits the measured vibration data to the control device 50. In other embodiments, knocking may be detected by the pressure sensor S1. When knocking occurs, the pressure in the combustion chamber 11 vibrates. By measuring this vibration, knocking can be detected. In this case, the knock sensor S2 may not be provided.

The exhaust valve box 5 is provided with an exhaust valve 6. The exhaust valve 6 is arranged in the combustion chamber 11 so as to open and close the exhaust port 5a. The exhaust valve 6 is connected to the drive device 7. The drive device 7 is provided in the exhaust valve box 5. The drive device 7 moves the exhaust valve 6 in a direction parallel to the reciprocating movement of the piston 2. When the exhaust valve 6 moves toward the piston 2, the exhaust port 5a is opened. When the exhaust valve 6 moves toward the exhaust valve box 5, the exhaust port 5a is closed.

An exhaust pipe 12 is connected to the exhaust valve box 5. The exhaust port 5a connects the combustion chamber 11 and the exhaust pipe 12. The exhaust pipe 12 is provided with an ammonia sensor S3. Since ammonia is toxic, the ammonia sensor S3 measures the concentration of ammonia in the exhaust gas in the exhaust pipe 12 in order to prevent the ammonia from being released to the outside. When unburned ammonia remains in the combustion chamber 11 and is exhausted to the exhaust pipe 12 (ammonia slip), ammonia is detected by the ammonia sensor S3. The ammonia sensor S3 is connected to the control device 50 by wire or wirelessly so as to be communicable with the control device 50, and transmits the measured ammonia concentration data to the control device 50.

The lower end of the cylinder 1 is surrounded by a cylinder jacket 9. A scavenging chamber 9a is formed inside the cylinder jacket 9. The scavenging chamber 9a is connected to the scavenging reservoir 8. An active gas (for example, air (for example, outside air)) is introduced into the scavenging reservoir 8. The active gas in the scavenging reservoir 8 is introduced into the scavenging chamber 9a. A plurality of scavenging ports 1a are provided in the lower part of the cylinder 1. The scavenging port 1a is a hole that penetrates the cylinder 1 from the inside to the outside. The plurality of scavenging ports 1a are formed so as to be separated from each other in the circumferential direction of the cylinder 1.

In the engine 10 as described above, when the piston 2 moves to the bottom dead center (position below the scavenging port 1a in FIG. 1), the differential pressure between the scavenging chamber 9a and the cylinder 1 causes the scavenging port 1a to the cylinder 1 to move. Active gas is inhaled inside. Subsequently, when the piston 2 moves from the bottom dead center to the top dead center, the active gas is compressed by the piston 2. Gas fuel and liquid fuel are injected from the first injection port R1 and the second injection port R2 with respect to the compressed active gas, respectively. The liquid fuel is vaporized and ignited under high temperature and high pressure. By the ignition of the liquid fuel, the gaseous fuel is also ignited and burned. The piston 2 moves toward the bottom dead center due to the expansion pressure due to combustion. The exhaust port 5a is opened, and the exhaust gas after combustion in the cylinder 1 is exhausted to the exhaust pipe 12 through the exhaust port 5a. Exhaust gas is further discharged to the outside through some components such as a purification device (not shown). After exhausting, the exhaust port 5a is closed.

The control device 50 includes, for example, an ECU (Engine Control Unit). The control device 50 includes components such as a central processing unit (CPU) and a storage device (a hard disk, a ROM in which a program or the like is stored, a RAM as a work area, etc.), and controls the system 100. .. The control device 50 may further include other components (for example, a display device such as a liquid crystal display or a touch panel, and an input device such as a keyboard, a button, or a touch panel).

As described above, the control device 50 is communicably connected to the pressure sensor S1, the knock sensor S2, and the ammonia sensor S3, and receives pressure data, vibration data, and ammonia concentration data, respectively. Based on these data, the control device 50 determines whether the combustion of the engine 10 is abnormal (that is, misfire (a phenomenon in which the fuel does not burn), knocking, or ammonia slip occurs during the operation of the engine 10). Whether or not) is determined, and the fuel used in the engine 10 is controlled based on the determination result (details will be described later).

For example, when a misfire occurs in the combustion chamber 11, the pressure in the combustion chamber 11 is lower than the normal pressure. For example, the storage device of the control device 50 may store a PV diagram showing the relationship between the volume V at each position of the piston 2 and the pressure with respect to each volume V. The control device 50 may determine whether or not a misfire has occurred in the combustion chamber 11 based on the pressure data from the pressure sensor S1 and the PV diagram.

When knocking occurs in the combustion chamber 11, the components defining the combustion chamber 11 vibrate more than the normal vibration. For example, the storage device of the control device 50 may store a threshold value for determining whether or not knocking has occurred. The control device 50 may determine whether or not knocking has occurred in the combustion chamber 11 based on the vibration data from the knock sensor S2 and the threshold value.

When ammonia slip occurs in the exhaust pipe 12, the concentration of ammonia in the exhaust gas flowing through the exhaust pipe 12 increases from the normal concentration. For example, the storage device of the control device 50 may store a threshold value for determining whether or not ammonia slip has occurred. The control device 50 may determine whether or not ammonia slip has occurred in the exhaust pipe 12 based on the concentration data from the ammonia sensor S3 and the threshold value.

Knocking, misfire and ammonia slip as described above can occur, for example, when the output of the engine 10 increases or decreases, or when the outside air temperature changes. The control device 50 controls the fuel used in the engine 10 in the event of these misfires, knocking, or ammonia slips.

Subsequently, the fuel used in the engine 10 will be described in detail.

In this embodiment, the engine 10 uses ammonia, hydrogen, natural gas and liquid fuel.

Specifically, the first tank T1 stores ammonia. The first tank T1 is connected to the first injection port R1 by the pipe L1. For example, the engine 10 has a valve V1 and a booster P1 on the pipe L1. Also, for example, the engine 10 has a valve (eg, a three-way valve) V11 and a catalyst C. For example, the catalyst C is connected in parallel to the pipe L1 via the valve V11. The catalyst C is heated by a heating means (for example, a heater or the like) (not shown). The catalyst C is, for example, ruthenium, alumina, or the like. Hydrogen can be produced from ammonia by passing the catalyst C through the catalyst C at a high temperature. In general, liquid hydrogen needs to be transported at an ultra-low temperature (about 20 K) under normal pressure, while liquid ammonia can be transported at room temperature (about 293 K) under a pressure of about 0.9 MPa. .. In this embodiment, the system 100 uses ammonia as a carrier for hydrogen, as described above. Therefore, in the system 100, hydrogen can be easily obtained on a ship without expensive cooling equipment. The valve V1, the booster P1 and the valve V11 are connected to the control device 50 by wire or wirelessly so as to be communicable with each other, and are controlled by the control device 50.

The second tank T2 stores natural gas (for example, LNG). The second tank T2 is connected to the first injection port R1 by the pipe L2. For example, the engine 10 has a valve V2 and a booster P2 on the pipe L2. The valve V2 and the booster P2 are wire-wired or wirelessly connected to the control device 50 in a communicable manner and are controlled by the control device 50.

According to the above configuration, at least one of ammonia, hydrogen or natural gas is injected from the first injection port R1 in an amount controlled by the control device 50.

The third tank T3 stores liquid fuel (for example, heavy oil, light oil, biofuel, etc.). The third tank T3 is connected to the second injection port R2 by the pipe L3. For example, the engine 10 has a valve V3 and a pump P3 on the pipe L3. The valve V3 and the pump P3 are wire-wired or wirelessly connected to the control device 50 in a communicable manner and are controlled by the control device 50.

According to the above configuration, the liquid fuel is injected from the second injection port R2 in an amount controlled by the control device 50.

FIG. 2 shows the fuel patterns PT1 to PT10 used in the dual fuel engine system of FIG. The engine 10 uses at least one of the above fuels, ammonia or hydrogen, as the main fuel (excluding the pattern PT1 in FIG. 2). When the combustion of the engine 10 is determined to be abnormal during operation using at least one of ammonia and hydrogen, the control device 50 adds at least one of ammonia, hydrogen, natural gas or liquid fuel to fuel. The engine 10 is controlled so as to change the blending (or blending ratio) of. In the present disclosure, "changing the fuel composition" may mean adding a fuel that is not used as the main fuel when at least one of ammonia and hydrogen is used as the main fuel. Further, in the present disclosure, "changing the ratio of the fuel mixture" means that when a mixed gas of ammonia and hydrogen is used as the main fuel, the ratio of either ammonia or hydrogen is used while maintaining the fuel combination. It can mean increasing. In this embodiment, a predetermined small amount of liquid fuel is used for ignition in all of the patterns PT1 to PT10.

[Pattern PT1: Liquid fuel]
In pattern PT1, only liquid fuel is used. Vessels have laws that stipulate that liquid fuel must be used when starting and stopping the engine. Therefore, the pattern PT1 is used, for example, when the engine 10 is started and stopped. Further, for example, when the engine 10 does not operate well during operation with other patterns PT2 to PT10, the fuel may be switched to the pattern PT1.

[Pattern PT2: Ammonia]
In pattern PT2, ammonia is mainly used. For example, the pattern PT2 is used when the engine 10 is stable and the output of the engine 10 does not change.

[Pattern PT3 to PT7: at least one of ammonia + hydrogen, natural gas or liquid fuel]
In patterns PT3 to PT7, in addition to ammonia, at least one of hydrogen, natural gas or liquid fuel is used. In general, ammonia is difficult to burn and can lead to misfire. When a misfire occurs in the combustion chamber 11, unburned ammonia is discharged to the exhaust pipe 12 (ammonia slip). Therefore, for example, when it is determined that a misfire or ammonia slip has occurred during the operation of the engine 10 by the above pattern PT2, the fuel is in the following patterns PT3 to PT7 in order to add a fuel that is more flammable than ammonia. It may be switched to either.

In pattern PT3, liquid fuel is used in addition to ammonia. That is, in the pattern PT3, in addition to a predetermined small amount of liquid fuel for ignition, additional liquid fuel is added. Liquid fuel stabilizes combustion.

In pattern PT4, natural gas is used in addition to ammonia. Combustion is stabilized by natural gas.

In pattern PT5, hydrogen is used in addition to ammonia. As mentioned above, ammonia is difficult to burn and can lead to misfires and ammonia slips. In contrast, hydrogen is easy to burn and can lead to knocking. Thus, ammonia and hydrogen have contradictory properties. Therefore, the use of hydrogen in addition to ammonia can enable stable combustion.

Regarding the above pattern PT5, for example, when it is determined that a misfire or ammonia slip occurs during the operation of the engine 10 by the pattern PT2 which mainly uses ammonia, the fuel is added in order to add hydrogen which is more combustible than ammonia. May be switched from pattern PT2 to pattern PT5.

Further, for example, when it is determined that knocking has occurred during the operation of the engine 10 by the pattern PT8 (described later) which mainly uses hydrogen, the fuel is the pattern PT8 in order to add ammonia which is harder to burn than hydrogen. May be switched to the pattern PT5.

Further, for example, the pattern PT5 may be used directly without being switched from the patterns PT2 and PT8 as described above. Specifically, when the engine 10 is stable and the output of the engine 10 does not change, the engine 10 may be operated in the pattern PT5 using a mixed gas of ammonia and hydrogen in a predetermined ratio. In this case, if a misfire or ammonia slip occurs during the operation of the engine 10 by the pattern PT5, hydrogen that is more flammable than ammonia may be added. In contrast, ammonia, which is less flammable than hydrogen, may be added if knocking occurs during operation of the engine 10 with pattern PT5.

In pattern PT6, hydrogen and liquid fuel are used in addition to ammonia. For example, in order to add liquid fuel to stabilize combustion if knocking, misfire or ammonia slip continues to occur after the engine 10 has been switched from pattern PT2, PT8 to pattern PT5 above, the fuel pattern. Further switching from PT5 to pattern PT6 may be performed.

In pattern PT7, hydrogen and natural gas are used in addition to ammonia. Similar to pattern PT6 above, for example, to add natural gas to stabilize combustion if knocking, misfire or ammonia slip continues to occur after the engine 10 has been switched from pattern PT2, PT8 to pattern PT5. In addition, the fuel may be further switched from the pattern PT5 to the pattern PT7.

[Pattern PT8: Hydrogen]
In pattern PT8, hydrogen is mainly used. For example, the pattern PT8 is used when the engine 10 is stable and the output of the engine 10 does not change.

[Pattern PT9, PT10: Hydrogen + natural gas or liquid fuel]
In patterns PT9 and PT10, natural gas or liquid fuel is used in addition to hydrogen. As mentioned above, hydrogen is easy to burn and can lead to knocking. So, for example, if it is determined that knocking has occurred while the engine 10 is running with the above pattern PT8 using hydrogen, the fuel will be patterned to add natural gas or liquid fuel to stabilize combustion. It may be switched from PT8 to any of the following patterns PT9 and PT10.

In pattern PT9, liquid fuel is used in addition to hydrogen. That is, in the pattern PT9, in addition to a predetermined small amount of liquid fuel for ignition, additional liquid fuel is added. Liquid fuel stabilizes combustion.

In pattern PT10, natural gas is used in addition to hydrogen. Combustion is stabilized by natural gas.

The amount of each fuel in each pattern as described above is determined by the control device 50 so that the total energy obtained from each fuel is equal to the output required for the engine 10. For example, if liquid fuel is added during operation using ammonia, the controller 50 reduces the use of ammonia when the addition of liquid fuel causes the total energy to be greater than the output required for the engine 10. As such, the engine 10 is controlled. The combination of fuels is not limited to the above patterns PT1 to PT10, and other combinations may be used.

Subsequently, an example of the operation of the system 100 will be described.

FIG. 3 is a flowchart showing an example of the operation of the dual fuel engine system 100 of FIG. In the example of FIG. 3, the system 100 mainly uses ammonia, and when it is determined that the combustion of the engine 10 is abnormal, the liquid fuel is added (pattern PT2 → pattern PT3). For example, the operation of FIG. 3 may be started when the engine 10 is stable and the operation is started in the pattern PT2.

The control device 50 determines whether or not knocking has occurred in the combustion chamber 11 (step S100). Specifically, the control device 50 may determine whether or not knocking has occurred in the engine 10 based on the vibration data from the knock sensor S2 and the threshold value stored in the storage device.

If it is determined in step S100 that knocking has not occurred in the combustion chamber 11 (NO), the control device 50 determines whether or not a misfire has occurred in the combustion chamber 11 (step S102). Specifically, the control device 50 may determine whether or not a misfire has occurred in the combustion chamber 11 based on the pressure data from the pressure sensor S1 and the PV diagram stored in the storage device.

If it is determined in step S102 that no misfire has occurred in the combustion chamber 11 (NO), the control device 50 determines whether or not ammonia slip has occurred in the exhaust pipe 12 (step S104). Specifically, the control device 50 may determine whether or not ammonia slip has occurred in the exhaust pipe 12 based on the concentration data from the ammonia sensor S3 and the threshold value stored in the storage device.

If it is determined in step S104 that ammonia slip has not occurred in the exhaust pipe 12 (NO), the control device 50 returns to step S100.

In step S100, it is determined that knocking has occurred in the combustion chamber 11 (YES), in step S102 it is determined that misfire has occurred in the combustion chamber 11 (YES), and in step S104, the exhaust pipe. If it is determined in step 12 that ammonia slip has occurred (YES), the control device 50 controls the engine 10 so as to add liquid fuel (step S106), and returns to step S100.

The control device 50 may repeat the above operation, for example, until it receives an arbitrary command (for example, a command for switching fuel (for example, a command for returning fuel to pattern PT2), or an engine 10. Command to stop, etc.). For example, the above operation may be repeated at predetermined intervals (for example, one hundred to several hundred milliseconds, one to several seconds, ten to several tens of seconds, or one to several minutes). The command may be input by the ship operator, for example, via the input device of the control device 50. Alternatively, the controller 50 may automatically return the fuel to pattern PT2, for example, if the output of the engine 10 is determined to be stable again. As mentioned above, knocking, misfire and ammonia slip can occur when the output of the engine 10 increases or decreases, so if it is determined that the output of the engine 10 is stable again, the fuel is a control device. It may be automatically returned to the pattern PT2 by 50.

In the example of FIG. 3, the system 100 mainly uses ammonia, and when it is determined that the combustion of the engine 10 is abnormal, the liquid fuel is added (pattern PT2 → pattern PT3). However, in another example, the system 100 may mainly use hydrogen (pattern PT8 → pattern PT9).

Further, in another example, the system 100 may mainly use a mixed gas of ammonia and hydrogen (pattern PT5 → pattern PT6). In this case, the system 100 may add ammonia or hydrogen instead of adding the liquid fuel when it is determined that the combustion of the engine 10 is abnormal (pattern PT5 → pattern PT5). For example, if knocking occurs, ammonia may be added. In this case, in step S106, ammonia is added instead of the liquid fuel. In contrast, hydrogen may be added in the event of a misfire or ammonia slip. In this case, in step S106, hydrogen is added instead of the liquid fuel.

Further, in another example, the system 100 mainly uses ammonia, and hydrogen may be added when it is determined that the combustion of the engine 10 is abnormal (pattern PT2 → pattern PT5). In this case, in step S106, hydrogen is added instead of the liquid fuel.

Further, in another example, the system 100 mainly uses ammonia (or hydrogen), and natural gas may be added when it is determined that the combustion of the engine 10 is abnormal (Pattern PT2 (Pattern PT2 (Pattern PT2). Alternatively, pattern PT8) → pattern PT10). In this case, in step S106, natural gas is added instead of the liquid fuel.

FIG. 4 is a flowchart showing another example of the operation of the dual fuel engine system 100 of FIG. In the example of FIG. 4, the system 100 mainly uses ammonia, and when it is determined that the combustion of the engine 10 is abnormal, hydrogen and liquid fuel are added stepwise (pattern PT2 → pattern PT5 → pattern). PT6). For example, the operation of FIG. 4 may be started when the engine 10 stabilizes and starts operation with the pattern PT2.

Steps S200 to S204 may be the same as the above steps S100 to S104, respectively.

In step S200, when it is determined that knocking has occurred in the combustion chamber 11 (YES), in step S202, when it is determined that misfire has occurred in the combustion chamber 11 (YES), and in step S204, the exhaust pipe. If it is determined in step 12 that ammonia slip has occurred (YES), the control device 50 controls the engine 10 so as to add hydrogen (step S206).

Subsequently, the control device 50 determines whether or not a predetermined amount or more of hydrogen has been added (step S208). If it is determined in step S208 that more than a predetermined amount of hydrogen has not been added (NO), the control device 50 returns to step S200. The above-mentioned predetermined amount may be stored in the storage device of the control device 50.

FIG. 5 shows the operation following FIG. If it is determined in step S208 above that a predetermined amount or more of hydrogen has been added (YES), the control device 50 proceeds to step S210. Steps S210 to S214 may be the same as the above steps S100 to S104, respectively.

In step S210, when it is determined that knocking has occurred in the combustion chamber 11 (YES), in step S212, when it is determined that misfire has occurred in the combustion chamber 11 (YES), and in step S214, the exhaust pipe. If it is determined in step 12 that ammonia slip has occurred (YES), the control device 50 controls the engine 10 to add liquid fuel instead of hydrogen (step S216), and returns to step S210.

Similar to the example of FIG. 3, the control device 50 may repeat the above operation until, for example, receiving an arbitrary command. Further, as in the example of FIG. 3, the control device 50 may automatically return the fuel to the pattern PT2, for example, when it is determined that the output of the engine 10 is stable again.

In the example of FIG. 4, the system 100 mainly uses ammonia, and when it is determined that the combustion of the engine 10 is abnormal, hydrogen and liquid fuel are added stepwise (pattern PT2 → pattern PT5 → pattern). PT6). However, in another example, the system 100 may primarily use hydrogen (Pattern PT8 → Pattern PT5 → Pattern PT6). In this case, in step S206 of FIG. 4, ammonia is added instead of hydrogen.

Further, in another example, the system 100 may mainly use a mixed gas of ammonia and hydrogen (pattern PT5 → pattern PT5 → pattern PT6). For example, when knocking occurs, ammonia may be added in step S206 of FIG. In contrast, in the event of a misfire or ammonia slip, hydrogen may be added as shown in step S206 of FIG.

Further, in another example, the system 100 mainly uses ammonia (or hydrogen), and when it is determined that the combustion of the engine 10 is abnormal, in step S216 of FIG. 5, instead of the liquid fuel. , Natural gas may be added (Pattern PT2 (or Pattern PT8) → Pattern PT5 → Pattern PT7).

The system 100 according to the above embodiment is knocked during operation using the engine 10 using ammonia, hydrogen, natural gas and liquid and using at least one of ammonia or hydrogen (patterns PT2, PT5, PT8). Determine if a misfire or ammonia slip has occurred, and if any of these are determined, add at least one of ammonia, hydrogen, natural gas or liquid fuel (Patterns PT3, PT4). , PT5, PT6, PT7, PT9, PT10), and a control device 50 that controls the engine 10 so as to change the fuel blending or the fuel blending ratio. Therefore, in the system 100, the fuel is adjusted so that the combustion of the engine 10 is stable. Therefore, it is possible to reduce the combustion abnormality of the engine 10.

Further, the control device 50 determines whether or not a misfire or ammonia slip has occurred in the engine 10 during operation using ammonia (patterns PT2 and PT5), and when it is determined that a misfire or ammonia slip has occurred. The engine 10 may be controlled so as to add liquid fuel (patterns PT3, PT6). In this case, misfire or ammonia slip can be reduced.

Further, the control device 50 determines whether or not a misfire or ammonia slip has occurred in the engine 10 during operation using ammonia (patterns PT2 and PT5), and when it is determined that a misfire or ammonia slip has occurred. The engine 10 may be controlled so as to add hydrogen (pattern PT5). In this case as well, misfire or ammonia slip can be reduced.

Further, in the above case, the control device 50 determines whether or not a misfire or ammonia slip has occurred in the engine 10 after adding hydrogen (pattern PT5), and it is determined that a misfire or ammonia slip has occurred. In some cases, the engine 10 may be controlled to add liquid fuel (Pattern PT6). In this case, misfire or ammonia lip can be reduced more reliably.

Although the embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to the above embodiments. It will be apparent to those skilled in the art that various changes or amendments may be conceived within the scope of the claims, which are also understood to belong to the technical scope of the present disclosure.

For example, in the above embodiment, the system 100 is applied to a ship. However, in other embodiments, the system 100 may be applied to other equipment or facilities (eg, stationary power generation systems or emergency power supplies, etc.). For example, when the system 100 is applied to a stationary power generation system, the system 100 may include a tank for storing hydrogen instead of the first tank T1 for storing ammonia. In this case, hydrogen may be produced using, for example, wind power generation. Ammonia can be produced from hydrogen by the well-known Haber process.

In the above embodiment, the engine 10 can use all of ammonia, hydrogen, natural gas and liquid fuel. However, in other embodiments, the engine 10 may use at least two fuels selected from the group consisting of ammonia, hydrogen, natural gas and liquid fuels and containing at least one of ammonia or hydrogen. .. For example, the system 100 may not include the second tank T2 and may not use natural gas. Further, for example, the system 100 may not be provided with the third tank T3 and may not use liquid fuel (except when the system 100 is applied to a ship). Also, for example, the system 100 may use only either ammonia or hydrogen.

In the above embodiment, liquid fuel is used as the ignition means. However, in other embodiments, spark plugs may be used as the ignition means.

In the above embodiment, the first injection port R1 is provided on the cylinder cover 4 so as to directly inject the gaseous fuel into the active gas. However, in other embodiments, the first injection port R1 may be provided at another position in the engine 10 to premix the gaseous fuel with the active gas. In this case, the first injection port R1 may be provided, for example, in the cylinder 1 at a position slightly above the cylinder jacket 9.

In the above embodiment, ammonia, hydrogen and natural gas are injected from the same first injection port R1. However, in other embodiments, an injection port for ammonia and hydrogen and another injection port for natural gas may be provided independently. In this case, for example, one injection port may be used for premixing and the other injection port may be used for direct injection.

This disclosure promotes the use of ammonia and hydrogen, which do not emit oxygen dioxide as fuels, and thus, for example, Goal 7 of the Sustainable Development Goals (SDGs), "Affordable, Reliable, Sustainable and Access to Modern Energy. Can contribute to “Securing” and Goal 13 “Taking emergency measures to combat climate change and its impacts”.

10 Dual fuel engine 50 Controller 100 Dual fuel engine system

Claims (4)

A dual fuel engine selected from the group consisting of ammonia, hydrogen, natural gas and liquid fuels and using at least two fuels containing at least one of ammonia or hydrogen.
During operation using at least one of ammonia and hydrogen, it is determined whether the combustion of the dual fuel engine is abnormal, and if it is determined that the combustion of the dual fuel engine is abnormal, ammonia, hydrogen, natural A control device that controls the dual fuel engine to add at least one of gas or liquid fuel to change the fuel composition or fuel composition ratio.
With dual fuel engine system. The control device determines whether or not a misfire or ammonia slip has occurred in the dual fuel engine during operation using ammonia, and if it is determined that a misfire or ammonia slip has occurred, liquid fuel is added. The dual fuel engine system according to claim 1, wherein the dual fuel engine is controlled so as to be used. The control device determines whether or not a misfire or ammonia slip has occurred in the dual fuel engine during operation using ammonia, and if it is determined that a misfire or ammonia slip has occurred, hydrogen is added. The dual fuel engine system according to claim 1, wherein the dual fuel engine is controlled as described above. After adding hydrogen, the control device determines whether the dual fuel engine has misfire or ammonia slip, and if it is determined that misfire or ammonia slip has occurred, the liquid fuel should be added. The dual fuel engine system according to claim 3, wherein the dual fuel engine is controlled.

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