Engine device

Abstract

Provided is an engine device capable of maintaining good exhaust gas properties without increasing the size of a device for purifying exhaust gas discharged from an ammonia co-combustion engine. An ammonia co-combustion engine device (1), which operates by combusting a main fuel containing ammonia and a hydrocarbon-based auxiliary fuel, is provided with a control device (9). The excess air ratio of the mixed gas of the main fuel and the air and / or the injection timing of the sub-fuel is controlled so that the discharge ratio of the unburned ammonia and the nitrogen oxide contained in the exhaust gas reaches a predetermined ratio.

Description

Technical Field

[0001] The present invention relates to an engine device including an ammonia co-firing engine that operates by combusting a main fuel containing at least ammonia and a hydrocarbon-based auxiliary fuel. Background Art

[0002] Conventional engine systems include ammonia-fueled engines that operate by combusting a main fuel containing at least ammonia and a hydrocarbon-based auxiliary fuel such as light oil. In engine systems, there is a demand for improved properties (properties and states) of exhaust gas emitted from ammonia-fueled engines.

[0003] For example, Patent Document 1 discloses an exhaust gas purification device for purifying exhaust gas from an internal combustion engine that uses ammonia as fuel. The device comprises: a catalyst having the function of reducing nitrogen oxides and oxidizing ammonia; an adsorbent disposed downstream of the catalyst and adsorbing ammonia in the exhaust gas; an activity state detection unit for detecting the activity state of the catalyst; a concentration acquisition unit for acquiring the concentration of the exhaust gas downstream of the adsorbent; and a control unit for controlling the amount of ammonia supplied by supplying ammonia to a fuel supply unit of the internal combustion engine. When the catalyst is active, the control unit uses the exhaust gas concentration acquired by the concentration acquisition unit to control the amount of ammonia supplied so as to maintain a constant concentration of the exhaust gas downstream of the adsorbent.

[0004] In Patent Document 2, an ammonia engine system includes an ammonia engine that uses ammonia as fuel and an ammonia cracker that includes an ammonia cracking catalyst that decomposes ammonia and decomposes ammonia to generate hydrogen. The ammonia engine system includes an ammonia oxidizer between the ammonia engine and the ammonia cracker.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-90894

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2010-121509 Summary of the Invention

[0009] However, conventional ammonia-fueled engines, such as those described in Patent Document 1, purify the exhaust gas by reducing nitrogen oxides and oxidizing ammonia in the exhaust gas using a catalyst. However, the amount or ratio of nitrogen oxides and ammonia in the exhaust gas is not controlled. Therefore, it is necessary to construct a device for purifying the exhaust gas based on the maximum expected nitrogen oxides and unburned ammonia in the exhaust gas, which may lead to a larger capacity and larger size of the device. Furthermore, reducing the amount of ammonia supplied to such an ammonia-fueled engine requires the use of other fuels to achieve the same output, which may increase greenhouse gas (GHG) emissions and reduce market value.

[0010] Furthermore, in conventional ammonia co-firing engines such as Patent Document 2, ammonia is mixed with hydrogen for combustion to improve the flammability of ammonia. However, this does not consider improving the deterioration of exhaust gas properties resulting from the combustion or purifying the exhaust gas.

[0011] An object of the present invention is to provide an engine device capable of maintaining good exhaust gas properties without increasing the size of an apparatus for purifying exhaust gas discharged from an ammonia co-firing engine.

[0012] In order to solve the above-mentioned problems, the engine device of the present invention is an ammonia co-firing engine device that operates by burning a main fuel containing ammonia and a hydrocarbon-based auxiliary fuel. The engine device is characterized in that at least one of the excess air ratio of the mixture of the main fuel and air and the injection period of the auxiliary fuel is controlled in such a way that the emission ratio of unburned ammonia and nitrogen oxides contained in the exhaust gas reaches a specified ratio.

[0013] According to the present invention, it is possible to provide an engine device capable of maintaining good exhaust gas properties without increasing the size of a device for purifying exhaust gas discharged from an ammonia co-firing engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a mimetic diagram showing an engine device according to an embodiment of the present invention.

[0015] Figure 2 This is a simulation diagram showing an ammonia co-firing engine in an engine device according to an embodiment of the present invention.

[0016] Figure 3 This is a graph showing the relationship between the injection timing of the auxiliary fuel and the air excess ratio of the main fuel in an ammonia co-firing engine, and represents the amount of unburned ammonia in the exhaust gas in the form of a map.

[0017] Figure 4This is a graph showing the relationship between the injection timing of the auxiliary fuel and the air excess ratio of the main fuel in an ammonia co-firing engine, and represents the amount of nitrogen oxides in the exhaust gas in the form of a map.

[0018] Figure 5 This is a graph showing the relationship between the injection timing of the auxiliary fuel and the excess air ratio of the main fuel in an ammonia co-firing engine, and represents the emission ratio between unburned ammonia and nitrogen oxides in the exhaust gas in the form of a map.

[0019] Figure 6 This is a graph showing the relationship between the hydrogen mixing ratio of the main fuel and the air excess ratio in an ammonia co-firing engine, and showing the amount of unburned ammonia in the exhaust gas in the form of a map.

[0020] Figure 7 This is a graph showing the relationship between the hydrogen mixing ratio of the main fuel and the air excess ratio in an ammonia co-firing engine, and maps the amount of nitrogen oxides in the exhaust gas.

[0021] Figure 8 This is a mimetic diagram showing an engine device according to another example of the present invention.

[0022] Figure 9 This is a graph showing a NO+NO 2 map in the relationship between the combustion temperature and the fuel-air equivalence ratio in an ammonia co-firing engine.

[0023] Figure 10 This is a graph showing a map of unburned ammonia in the relationship between the combustion temperature and the fuel-air equivalence ratio in an ammonia co-firing engine.

[0024] Description of Reference Numerals

[0025] 1 Engine unit, 2 Ammonia co-firing engine, 3 Intake passage, 4 Exhaust passage, 5 Main fuel supply device, 6 Auxiliary fuel supply device, 7 Selective reduction catalyst, 7a Reductant supply unit, 8 Ammonia adsorption catalyst, 9 Control device, 11 Ammonia tank, 12 Ammonia supply unit, 13 Ammonia decomposition device, 14 Hydrogen tank, 15 Hydrogen supply unit, 16 Auxiliary fuel tank, 17 Auxiliary fuel supply unit, 21 Cylinder, 21a Combustion chamber, 26 Auxiliary fuel injection unit, 35 Ammonia injection unit, 36 Hydrogen injection unit, 50 Intake throttle valve, 51 Supercharger, 51a Turbine, 51b Compressor, 51c Variable nozzle, 52 Intercooler, 53 Recirculation device, 53a Recirculation passage, 53b Recirculation cooler, 53c Recirculation valve, 54 Intake bypass passage, 54a Intake bypass valve, 55 Wastegate, 55a Wastegate valve DETAILED DESCRIPTION

[0026] Referring to the accompanying drawings, an engine device 1 according to an embodiment of the present invention will be described. Figure 1As shown, the engine device 1 includes an ammonia co-burning engine 2, an intake passage 3, an exhaust passage 4, a main fuel supply device 5, and an auxiliary fuel supply device 6. The engine device 1 also includes a selective reduction catalyst 7, an ammonia adsorption catalyst 8, and a control device 9.

[0027] In this embodiment, the engine device 1 is an ammonia-fueled engine device. The ammonia-fueled engine 2 is configured to operate by combusting a main fuel containing at least ammonia and at least one of a hydrocarbon-based auxiliary fuel such as light oil. A mixture of the main fuel and air is supplied to the combustion chamber 21a of each cylinder 21 of the ammonia-fueled engine 2, where the main fuel mixture and the auxiliary fuel are combusted. The supply of the main fuel and the auxiliary fuel to the engine device 1 is controlled by a control device 9.

[0028] The main fuel supply device 5 includes an ammonia tank 11 , an ammonia supply unit 12 , an ammonia decomposition device 13 , a hydrogen tank 14 , and a hydrogen supply unit 15 .

[0029] The ammonia tank 11 is filled with ammonia as the main fuel from the outside and stored in a liquid state. The ammonia supply unit 12 is constructed to have a pump connected to the ammonia tank 11, and is controlled by the control device 9 to introduce ammonia from the ammonia tank 11 and supply ammonia fuel in a liquid state or a gaseous state to the ammonia injection unit 35 of the ammonia co-firing engine 2.

[0030] The ammonia decomposition device 13 introduces ammonia from the ammonia tank 11, decomposes and reforms it to produce hydrogen fuel, and stores the gaseous hydrogen in the hydrogen tank 14. The hydrogen supply unit 15 is configured to include a pump connected to the hydrogen tank 14, and is controlled by the control device 9 to introduce hydrogen from the hydrogen tank 14 and supply the gaseous hydrogen fuel to the hydrogen injection unit 36 ​​of the ammonia co-firing engine 2.

[0031] The auxiliary fuel supply device 6 includes an auxiliary fuel tank 16 and an auxiliary fuel supply unit 17. The auxiliary fuel tank 16 stores an auxiliary fuel, which is a hydrocarbon-based fuel such as light oil, in a liquid state. The auxiliary fuel supply unit 17 includes a pump connected to the auxiliary fuel tank 16 and is controlled by the control device 9 to introduce the auxiliary fuel from the auxiliary fuel tank 16 and supply the liquid auxiliary fuel to the auxiliary fuel injection unit 26 of the ammonia-fueled engine 2.

[0032] The ammonia co-firing engine 2 is, for example, a four-stroke engine, and is configured such that a cylinder block 20 includes a plurality of cylinders 21 and a crankcase 22 (see Figure 2 ). Figure 1 In the figure, although four cylinders 21 are shown, the number of cylinders 21 is not limited to four. Figure 2 As shown, it is composed of a cylinder 23, a piston 24, and a cylinder head 25.

[0033] The cylinder tube 23 is formed in a cylindrical shape, for example, within the cylinder block 20. The piston 24 is slidably housed within the cylinder tube 23. A cylinder head 25 is mounted on the upper side of the cylinder tube 23. A combustion chamber 21a is formed inside the cylinder tube 23 and the cylinder head 25. The cylinder head 25 is provided with an auxiliary fuel injection unit 26 for injecting auxiliary fuel into the combustion chamber 21a.

[0034] For example, the auxiliary fuel injection unit 26 is composed of a device such as a droplet injection type injector that injects a small amount of auxiliary fuel. The auxiliary fuel injection unit 26 controls the injection amount, injection pressure, injection timing, etc. of the auxiliary fuel by the control device 9. The auxiliary fuel injection unit 26 uses the hydrocarbon-based liquid auxiliary fuel to compress and autoignite the mixture of the main fuel and air in the combustion chamber 21a, causing combustion.

[0035] Each cylinder bore 23 of the plurality of cylinders 21 communicates with a crankcase 22, and a crankshaft 27 is rotatably supported on the crankcase 22. The piston 24 of each cylinder 21 is connected to the crankshaft 27 via a connecting rod 28, and the reciprocating motion of the piston 24 is converted into rotational motion of the crankshaft 27 via the connecting rod 28.

[0036] The cylinder head 25 has an intake port 29 and an exhaust port 30 communicating with the combustion chamber 21a of the cylinder 23, and includes an intake valve 31 and an exhaust valve 32 for opening and closing the intake port 29 and the exhaust port 30 with respect to the combustion chamber 21a, respectively.

[0037] The intake port 29 is connected to the intake passage 3 and introduces air supplied from the intake passage 3 into the combustion chamber 21a. The exhaust port 30 is connected to the exhaust passage 4 and discharges exhaust gas generated in the combustion chamber 21a into the exhaust passage 4. By opening the intake valve 31, a mixture of the main fuel and air can be drawn into the combustion chamber 21a through the intake port 29. On the other hand, by opening the exhaust valve 32, the exhaust gas generated in the combustion chamber 21a can be discharged through the exhaust port 30.

[0038] The intake passage 3 is connected to the multiple cylinders 21 of the ammonia-fueled engine 2 and supplies compressed and cooled air to each cylinder 21. A mixture of air supplied from the intake passage 3 and main fuel supplied from the main fuel supply device 5 is supplied from the intake passage 3 to the combustion chamber 21a of each cylinder 21. For example, the intake passage 3 is connected to the ammonia-fueled engine 2 via an intake manifold 33. The intake manifold 33 has branching flow paths 33a that branch toward the multiple cylinders 21. Each branch flow path 33a is connected to a respective intake port 29.

[0039] In addition, an ammonia injection unit 35 for supplying ammonia fuel as a main fuel from the main fuel supply device 5 toward each combustion chamber 21a and a hydrogen injection unit 36 ​​for supplying hydrogen fuel as a main fuel are provided in the intake passage 3, the branch flow path 33a, the intake port 29 or the cylinder head 25.

[0040] The ammonia injection unit 35 and the hydrogen injection unit 36 ​​control the injection amount and injection timing of the ammonia fuel and hydrogen fuel respectively by the control unit 9. The control unit 9 controls the injection amount of the air and ammonia fuel and hydrogen fuel supplied from the intake passage 3, thereby controlling the excess air ratio in the mixed air supplied to the combustion chamber 21a. The ammonia injection unit 35 and the hydrogen injection unit 36 ​​can be composed of a supply valve or injector provided for each combustion chamber 21a to inject the ammonia fuel and hydrogen fuel respectively.

[0041] in addition, Figure 2 In the figure, an example is shown in which the ammonia injection unit 35 and the hydrogen injection unit 36 ​​are provided in the intake manifold 33, injecting the ammonia fuel and the hydrogen fuel into the branch flow path 33a, and supplying the ammonia fuel and the hydrogen fuel to the combustion chamber 21a through the intake port 29. However, the present invention is not limited to this example. Alternatively, the ammonia injection unit 35 and the hydrogen injection unit 36 ​​may be provided in the intake passage 3, injecting the ammonia fuel and the hydrogen fuel into the intake passage 3, and supplying the ammonia fuel and the hydrogen fuel to the combustion chamber 21a through the intake passage 3 and the intake port 29. Alternatively, the ammonia injection unit 35 and the hydrogen injection unit 36 ​​may be provided in the cylinder 23 or the cylinder head 25, and injecting the ammonia fuel and the hydrogen fuel directly into the combustion chamber 21a for supply.

[0042] The exhaust passage 4 is connected to the multiple cylinders 21 of the ammonia-fueled engine 2, allowing exhaust gas generated in each cylinder 21 to flow and be discharged. For example, the exhaust passage 4 is connected to the ammonia-fueled engine 2 via an exhaust manifold 34. The exhaust manifold 34 has branching flow paths 34a that branch toward the multiple cylinders 21, and each branch flow path 34a is connected to a respective exhaust port 30.

[0043] The exhaust passage 4 is connected to a selective reduction catalyst 7 and an ammonia adsorption catalyst 8 on the downstream side in the exhaust direction for treating exhaust gas flowing through the exhaust passage 4. The selective reduction catalyst 7 and the ammonia adsorption catalyst 8 are arranged in series through the exhaust passage 4.

[0044] A selective reduction catalyst 7 is disposed in the exhaust passage 4. It selectively reduces nitrogen oxides contained in the exhaust gas flowing through the exhaust passage 4 using a reducing agent such as urea water, thereby purifying the exhaust gas of ammonia and nitrogen oxides. A reducing agent supply unit 7a is disposed in the exhaust passage 4 upstream of the selective reduction catalyst 7 in the exhaust direction. The reducing agent supply unit 7a supplies reducing agent to the selective reduction catalyst 7. The amount of reducing agent supplied by the reducing agent supply unit 7a is controlled by a control device 9.

[0045] For example, the selective reduction catalyst 7 causes ammonia and nitrogen oxides to undergo a reduction reaction in a ratio (proportion) of one to one concentration or molar number, and the reducing agent supply unit 7a is controlled by the control device 9 to supply the reducing agent in a manner such that the concentration or molar number of ammonia and nitrogen oxides introduced into the selective reduction catalyst 7 together with the exhaust gas is one to one.

[0046] Ammonia adsorption catalyst 8 is disposed in exhaust passage 4 upstream of selective reduction catalyst 7 in the exhaust direction, and adsorbs ammonia contained in the exhaust gas flowing through exhaust passage 4, thereby purifying the exhaust gas of ammonia. Specifically, ammonia adsorption catalyst 8 reduces the concentration and / or number of moles of ammonia introduced into selective reduction catalyst 7 from the exhaust gas by adsorbing ammonia.

[0047] For example, the ammonia adsorption catalyst 8 may be composed of activated carbon, zeolite, Prussian blue, MOF (also known as porous metal complex or PCP (porous coordination polymer)), etc. as a material that adsorbs ammonia. Alternatively, in addition to having the function of adsorbing ammonia, the ammonia adsorption catalyst 8 may be composed of Fe ion-exchanged zeolite, Cu ion-exchanged zeolite, etc. as a material that reacts with nitrogen oxides.

[0048] Furthermore, the ammonia adsorption catalyst 8 is configured such that, when ammonia is adsorbed on the ammonia adsorption catalyst 8, when the exhaust gas passes through the ammonia adsorption catalyst 8, the ammonia is desorbed from the ammonia adsorption catalyst 8 by utilizing wind power of the exhaust gas or a reaction with nitrogen oxides. In this case, the ammonia adsorption catalyst 8 may desorb ammonia at a predetermined desorption temperature or above.

[0049] The control unit 9 is a computer such as an ECU (Engine Control Unit) that controls the operation of the ammonia-burning engine 2. It includes a CPU, ROM, RAM, and other components and is configured to control various components of the ammonia-burning engine 2. The control unit 9 can store various programs for controlling the ammonia-burning engine 2 and controls the ammonia-burning engine 2 by reading and executing the programs.

[0050] Next, supply control of main fuels such as ammonia and hydrogen fuel and auxiliary fuels such as diesel fuel in the engine device 1 will be described.

[0051] Figures 3 to 5 In FIG. 1 , the horizontal axis represents the injection timing of the auxiliary fuel supplied to the combustion chamber 21 a , and the vertical axis represents the excess air ratio with respect to ammonia in the air-fuel mixture supplied to the combustion chamber 21 a . Figure 3In the figure, the relationship between the auxiliary fuel injection period and the excess air ratio is shown: a stable region 40 in which the ammonia co-firing engine 2 can operate stably is shown, and a map is used to show that the amount of unburned ammonia contained in the exhaust gas within the stable region 40 increases in the direction indicated by the white arrow 41. Figure 4 In the figure, the relationship between the auxiliary fuel injection period and the excess air ratio is shown: a stable region 40 in which the ammonia co-firing engine 2 can operate stably is shown, and a mapping is used to show that the amount of nitrogen oxides contained in the exhaust gas within the stable region 40 increases in the direction indicated by the white arrow 42. Figure 5 In the figure, the relationship between the auxiliary fuel injection period and the excess air ratio is shown: a stable region 40 in which the ammonia co-firing engine 2 can operate stably, and a map is used to show the emission ratio of unburned ammonia and nitrogen oxides contained in the exhaust gas within the stable region 40. In this map, the ratio of ammonia to nitrogen oxides decreases in the direction indicated by the white arrow 43.

[0052] Therefore, based on the relationship between the auxiliary fuel injection timing and the main fuel's excess air ratio, the control device 9 controls at least one of the main fuel's excess air ratio and the auxiliary fuel's injection timing so that the emission ratio of unburned ammonia and nitrogen oxides contained in the exhaust gas generated by the combustion of the main fuel and auxiliary fuel reaches a predetermined target ratio (a target value or a target range, i.e., a predetermined ratio). The control device 9 controls the main fuel's excess air ratio by controlling the supply of ammonia from the ammonia supply unit 12 or the ammonia injection unit 35 and the intake of air into the intake passage 3. The control device 9 controls the auxiliary fuel's injection timing by controlling the supply of auxiliary fuel from the auxiliary fuel injection unit 26.

[0053] For example, when the emission ratio of unburned ammonia is low, the control device 9 controls the system so as to increase the amount of unburned ammonia by increasing or decreasing the excess air ratio of the main fuel or retarding the injection timing of the auxiliary fuel. When the emission ratio of nitrogen oxides is low, the control device 9 controls the system so as to increase the amount of nitrogen oxides by increasing or decreasing the excess air ratio of the main fuel or advancing the injection timing of the auxiliary fuel.

[0054] Furthermore, the engine device 1 may obtain various data on the emission ratios of unburned ammonia and nitrogen oxides in the exhaust gas for various data on the injection timing of the auxiliary fuel and the air excess ratio of the main fuel while the ammonia co-firing engine 2 is previously operated on a trial basis. A map representing the relationship between the injection timing of the auxiliary fuel and the air excess ratio of the main fuel may be created and stored in advance. The map indicates the emission ratios of unburned ammonia and nitrogen oxides in the exhaust gas within the stable region 40. Alternatively, the engine device 1 may obtain various data on the emission ratios of unburned ammonia and nitrogen oxides in the exhaust gas for various data on the injection timing of the auxiliary fuel and the air excess ratio of the main fuel while the ammonia co-firing engine 2 is actually operated, and the accumulated data may be used to create and store a map representing the emission ratios of unburned ammonia and nitrogen oxides in the exhaust gas within the stable region 40.

[0055] Moreover, the control device 9 obtains the current data of the injection period of the auxiliary fuel and the excess air ratio of the main fuel, and refers to the stored mapping representing the emission ratio of unburned ammonia and nitrogen oxides, thereby calculating the change in the injection period of the auxiliary fuel and the excess air ratio of the main fuel required to achieve the specified target ratio, and controls the injection period of the auxiliary fuel and the excess air ratio of the main fuel based on the change.

[0056] In addition, Figures 6 and 7 In FIG. 2 , the horizontal axis represents the hydrogen mixing ratio (hydrogen mixing proportion) of the main fuel composed of ammonia and hydrogen supplied to the combustion chamber 21 a , and the vertical axis represents the excess air ratio relative to the main fuel in the mixture supplied to the combustion chamber 21 a . Figure 6 In the figure, the relationship between the hydrogen mixing ratio and the excess air ratio is shown: a stable region 40 in which the ammonia co-firing engine 2 can operate stably is shown, and a map is used to show that the amount of unburned ammonia contained in the exhaust gas within the stable region 40 increases in the direction indicated by the white arrow 44. Figure 7 , the relationship between the hydrogen mixing ratio and the excess air ratio shows a stable region 40 in which the ammonia co-firing engine 2 can operate stably, and a map shows that the amount of nitrogen oxides contained in the exhaust gas increases in the direction indicated by white arrow 45 within the stable region 40. Although not shown, the relationship between the hydrogen mixing ratio and the excess air ratio can also be shown in a map showing the emission ratio of unburned ammonia and nitrogen oxides contained in the exhaust gas within the stable region in which the ammonia co-firing engine 2 can operate stably. In this map, the emission ratio is in a predetermined direction, enabling more stable combustion.

[0057] Therefore, instead of controlling the air excess ratio of the main fuel mixture or the injection timing of the auxiliary fuel, the control device 9 controls the mixing ratio of ammonia and hydrogen in the main fuel (ammonia mixing ratio or hydrogen mixing ratio) based on the relationship between the main fuel's hydrogen mixing ratio and the air excess ratio, so that the emission ratio of unburned ammonia and nitrogen oxides contained in the exhaust gas generated by the combustion of the main fuel and the auxiliary fuel reaches a predetermined target ratio (a target value or a target range, i.e., a predetermined ratio). The control device 9 controls the main fuel mixing ratio by controlling the supply of ammonia from the ammonia injection unit 35 and the supply of hydrogen from the hydrogen injection unit 36.

[0058] For example, when the emission ratio of unburned ammonia is low, the control device 9 controls the fuel so as to increase the amount of unburned ammonia by increasing the mixing ratio of ammonia in the main fuel (ammonia mixing ratio) or decrease the mixing ratio of hydrogen (hydrogen mixing ratio). When the emission ratio of nitrogen oxides is low, the control device 9 controls the fuel so as to increase the mixing ratio of hydrogen in the main fuel (hydrogen mixing ratio) or decrease the mixing ratio of ammonia (ammonia mixing ratio) in order to increase the amount of nitrogen oxides.

[0059] Furthermore, the engine device 1 may obtain various data on the emission ratios of unburned ammonia and nitrogen oxides in the exhaust gas for various data on the hydrogen mixing ratio of the main fuel and the air excess ratio of the main fuel while the ammonia co-firing engine 2 is previously operated on a trial basis. A map representing the relationship between the hydrogen mixing ratio of the main fuel and the air excess ratio of the main fuel is created and stored in advance. The map indicates the emission ratios of unburned ammonia and nitrogen oxides in the exhaust gas within the stable region 40. Alternatively, the engine device 1 may obtain various data on the emission ratios of unburned ammonia and nitrogen oxides in the exhaust gas for various data on the hydrogen mixing ratio of the main fuel and the air excess ratio of the main fuel while the ammonia co-firing engine 2 is actually operated, and the accumulated data may be used to create a map representing the emission ratios of unburned ammonia and nitrogen oxides in the exhaust gas within the stable region 40.

[0060] Moreover, the control device 9 obtains the current data of the hydrogen mixing ratio of the main fuel and the excess air ratio of the main fuel, and refers to the stored mapping representing the emission ratio of unburned ammonia and nitrogen oxides, thereby calculating the changes in the hydrogen mixing ratio of the main fuel and the excess air ratio of the main fuel required to achieve the specified target ratio, and controls the hydrogen mixing ratio of the main fuel and the excess air ratio of the main fuel based on the changes.

[0061] Alternatively, the control device 9 may also control at least one of the excess air ratio of the main fuel mixture, the injection period of the auxiliary fuel, and the hydrogen mixing ratio of the main fuel based on the relationship between the auxiliary fuel injection period and the excess air ratio in addition to the relationship between the auxiliary fuel injection period and the excess air ratio, so that the emission ratio of unburned ammonia and nitrogen oxides contained in the exhaust gas generated by the combustion of the main fuel and the auxiliary fuel reaches a prescribed target ratio.

[0062] As described above, according to the present invention, an ammonia co-firing engine device that operates by burning a main fuel containing ammonia and a hydrocarbon-based auxiliary fuel, that is, an engine device 1, controls at least one of the excess air ratio of the mixture of the main fuel and air and the injection period of the auxiliary fuel through the control device 9 in such a way that the emission ratio of unburned ammonia and nitrogen oxides contained in the exhaust gas reaches a prescribed target ratio (prescribed ratio).

[0063] Accordingly, according to the engine device 1 of the present invention, the emission ratio of unburned ammonia and nitrogen oxides in the exhaust gas can be adjusted without changing the operating load of the ammonia co-firing engine 2 or the ammonia input ratio (supply ratio) of the main fuel, thereby reducing greenhouse gas emissions (GHG).

[0064] Alternatively, the engine device 1 mixes hydrogen and ammonia to generate a main fuel, and the control device 9 controls the mixing ratio of ammonia and hydrogen in the main fuel so that the emission ratio of unburned ammonia and nitrogen oxides contained in the exhaust gas reaches a specified target ratio (specified ratio).

[0065] According to the engine device 1 of the present invention, when the unburned ammonia and nitrogen oxides in the exhaust gas are in a trade-off relationship during purification, the emission ratio of unburned ammonia and nitrogen oxides in the exhaust gas can be adjusted by adjusting the mixing ratio of ammonia and hydrogen in the main fuel.

[0066] Alternatively, the engine device 1 mixes hydrogen and ammonia to generate a main fuel, and controls at least one of the excess air ratio of the mixture of the main fuel and air, the injection period of the auxiliary fuel, and the mixing ratio of ammonia and hydrogen in the main fuel through the control device 9 in such a way that the emission ratio of unburned ammonia and nitrogen oxides contained in the exhaust gas reaches a prescribed target ratio (prescribed ratio).

[0067] Accordingly, according to the engine device 1 of the present invention, by appropriately combining and adjusting the excess air ratio of the mixture of the main fuel and air, the injection period of the auxiliary fuel, and the mixing ratio of ammonia and hydrogen in the main fuel, the emission ratio of unburned ammonia and nitrogen oxides in the exhaust gas can be more appropriately adjusted.

[0068] In addition, the engine device 1 of the present invention is controlled by the control device 9 in the following manner: the emission ratio of unburned ammonia in the exhaust gas and the emission ratio of nitrogen oxides are increased by increasing or decreasing the air excess ratio of the main fuel, delaying the injection period of the auxiliary fuel, and increasing the mixing ratio of ammonia in the main fuel, so that the emission ratio of unburned ammonia reaches a specified target ratio.

[0069] Thus, when the engine device 1 is purifying exhaust gas using the selective reduction catalyst 7 and the like, and it is predicted that nitrogen oxides will be generated in the exhaust gas in an amount greater than that required for purification, for example, greater than the capacity of the selective reduction catalyst 7, the engine device 1 can reduce the amount of nitrogen oxides emitted and increase the amount of unburned ammonia emitted by increasing the ammonia co-firing ratio. Consequently, an appropriate amount of nitrogen oxides can be generated in the exhaust gas to be purified, enabling the exhaust gas to be appropriately purified.

[0070] In addition, the engine device 1 of the present invention is controlled by the control device 9 in the following manner: the emission ratio of unburned ammonia in the exhaust gas and the emission ratio of nitrogen oxides in the nitrogen oxides emission ratio are increased by at least one of increasing or decreasing the air excess ratio of the main fuel, advancing the injection period of the auxiliary fuel, and increasing the hydrogen mixing ratio of the main fuel (hydrogen mixing ratio), so that the emission ratio of nitrogen oxides reaches a specified target ratio.

[0071] Thus, when the engine device 1 is purifying exhaust gas using the ammonia adsorption catalyst 8 and the like, and predicts that an amount of unburned ammonia exceeding an appropriate amount for purification, for example, exceeding the capacity of the ammonia adsorption catalyst 8, will be generated in the exhaust gas, the ammonia co-combustion ratio can be reduced, thereby reducing the amount of unburned ammonia emitted and increasing the amount of nitrogen oxides emitted. Consequently, an appropriate amount of unburned ammonia can be generated in the exhaust gas, enabling the exhaust gas to be appropriately purified.

[0072] Furthermore, the engine device 1 of the present invention includes a selective reduction catalyst 7 for reducing nitrogen oxides contained in the exhaust gas using a reducing agent, and an ammonia adsorption catalyst 8 for adsorbing unburned ammonia contained in the exhaust gas.

[0073] With this, the engine device 1 can adjust the emission ratios of unburned ammonia and nitrogen oxides contained in the exhaust gas in coordination with the purification of the exhaust gas by the selective reduction catalyst 7 and the ammonia adsorption catalyst 8 .

[0074] Furthermore, the engine device 1 of the present invention reforms ammonia by the ammonia decomposition device 13 and the like to generate hydrogen fuel.

[0075] According to this, the engine device 1 does not need to retain a large amount of hydrogen as fuel, and can use the hydrogen generated by reforming ammonia as the main fuel.

[0076] In addition, in the above-mentioned embodiment, although an example is described in which ammonia is introduced from the ammonia tank 11 through the ammonia decomposition device 13 and decomposed and reformed to generate hydrogen fuel, and the gaseous hydrogen is stored in the hydrogen tank 14, the present invention is not limited to this example, and the gaseous hydrogen can also be filled from the outside and stored in the hydrogen tank 14.

[0077] In addition, in the above-mentioned embodiment, although an example is described in which hydrogen and ammonia are mixed to generate a main fuel, and the control device 9 is used to control at least one of the excess air ratio of the mixture of the main fuel and air, the injection period of the auxiliary fuel, and the mixing ratio of ammonia and hydrogen in the main fuel in such a manner that the emission ratio of unburned ammonia and nitrogen oxides contained in the exhaust gas reaches a prescribed target ratio, the present invention is not limited to this example.

[0078] In other examples, the engine device 1 is Figure 8 As shown, in addition to the configuration of the above-described embodiment, the engine device 1 further includes an intake throttle valve 50 , a supercharger 51 , an intercooler 52 , and a recirculation device 53 (EGR device). Furthermore, the engine device 1 includes an intake bypass passage 54 and a wastegate 55 .

[0079] Moreover, the engine device 1 is constructed so as to increase the emission ratio of unburned ammonia in the exhaust gas and nitrogen oxides among the emission ratios of nitrogen oxides, by reducing the EGR rate of the recirculation device 53, increasing the injection pressure of the auxiliary fuel of the auxiliary fuel injection portion 26, increasing the amount of air bypassed from the intake passage 3 to the exhaust passage 4 on the intake bypass passage 54 (i.e., the intake bypass amount), increasing the opening of the waste gate 55 of the supercharger 51, and increasing the opening of the variable nozzle 51c of the supercharger 51, in addition to or instead of the above-mentioned excess air ratio of the mixture, the injection timing of the auxiliary fuel, and the mixing ratio of the main fuel, thereby controlling the emission ratio of nitrogen oxides to reach a specified target ratio (specified ratio).

[0080] Specifically, the engine device 1 is provided with a supercharger 51 , an intercooler 52 , and an intake throttle valve 50 in this order from the upstream side in the intake direction of the intake passage 3 .

[0081] The supercharger 51 includes a turbine 51a and a compressor 51b located in the exhaust passage 4. The turbine 51a is provided with a variable nozzle 51c that adjusts the passage area of ​​the exhaust gas flowing into the turbine 51a. The supercharger 51 rotates the turbine 51a using the exhaust gas flowing through the exhaust passage 4. The rotational force of the turbine 51a drives the compressor 51b, thereby compressing the air flowing through the intake passage 3.

[0082] The recirculation device 53 includes a recirculation passage 53a, a recirculation cooler 53b, and a recirculation valve 53c. The recirculation passage 53a is connected to the exhaust passage 4 upstream of the supercharger 51 (turbine 51a) in the exhaust direction, and is connected to the intake passage 3 downstream of the intercooler 52 in the intake direction. The recirculation device 53 uses the recirculation cooler 53b to cool the exhaust gas flowing through the exhaust passage 4 upstream of the supercharger 51 in the exhaust direction, recirculates the gas, and supplies it to the intake passage 3 downstream of the intercooler 52 in the intake direction. The recirculation device 53 controls the opening of the recirculation valve 53c by the control device 9, thereby adjusting the flow rate of the recirculated exhaust gas flowing into the intake passage 3 and thereby adjusting the oxygen content of the air flowing through the intake passage 3.

[0083] Furthermore, in the engine device 1, an intake bypass passage 54 is provided to connect a position downstream of the supercharger 51 in the intake direction of the intake passage 3 and a position upstream of the supercharger 51 in the exhaust direction of the exhaust passage 4 for bypassing the intake air. An intake bypass valve 54a for adjusting the amount of intake bypass is provided in the intake bypass passage 54. In the engine device 1, a wastegate 55 is provided to connect a position upstream of the supercharger 51 and a position downstream of the supercharger 51 in the exhaust direction of the exhaust passage 4 for bypassing the intake air. A wastegate valve 55a for adjusting the amount of exhaust bypass is provided in the wastegate 55.

[0084] Furthermore, the engine device 1 controls the recirculation valve 53c of the recirculation device 53 via the control device 9 to reduce the ratio of exhaust gas recirculated from the exhaust passage 4 to the intake passage 3 through the recirculation device 53, that is, the EGR rate. Consequently, control is performed such that the combustion temperature within the combustion chamber 21a is increased by reducing the exhaust gas recirculated into the intake air, thereby increasing the emission ratio of nitrogen oxides in the exhaust gas and achieving a predetermined target ratio (predetermined ratio).

[0085] Alternatively, the engine device 1 controls the auxiliary fuel injection unit 26 via the control device 9 to increase the injection pressure of the auxiliary fuel injected into the combustion chamber 21a. This controls the combustion of the auxiliary fuel at the increased injection pressure to increase the combustion temperature within the combustion chamber 21a, thereby increasing the emission rate of nitrogen oxides in the exhaust gas and achieving a predetermined target emission rate.

[0086] Alternatively, the engine device 1 controls the intake bypass valve 54a via the control device 9 to increase the amount of intake bypass air flowing into the exhaust passage 4. This controls the engine device 1 so that the proportion of air in the intake air is reduced and the proportion of fuel is increased, thereby raising the combustion temperature in the combustion chamber 21a and increasing the emission rate of nitrogen oxides in the exhaust gas, so that the emission rate of nitrogen oxides reaches a predetermined target rate.

[0087] Alternatively, the engine device 1 controls the wastegate valve 55a via the control device 9 to increase the opening of the wastegate 55. This control is performed such that the proportion of air in the intake air is reduced by increasing the amount of residual gas, thereby reducing the air compression amount of the supercharger 51, and increasing the proportion of fuel to raise the combustion temperature in the combustion chamber 21a and increase the emission rate of nitrogen oxides in the exhaust gas, so that the emission rate of nitrogen oxides reaches a predetermined target rate.

[0088] Alternatively, the engine device 1 controls the variable nozzle 51c via the control device 9 to increase the opening of the variable nozzle 51c, thereby increasing the passage area of ​​the turbine 51a of the supercharger 51. This control is performed in such a manner that the proportion of air in the intake air is reduced by increasing the amount of residual gas, thereby reducing the amount of air compression in the supercharger 51, and increasing the proportion of fuel, thereby raising the combustion temperature in the combustion chamber 21a and increasing the emission rate of nitrogen oxides in the exhaust gas, so that the emission rate of nitrogen oxides reaches a predetermined target rate.

[0089] Figure 9 In FIG. 2 , the horizontal axis represents the combustion temperature in the combustion chamber 21 a , and the vertical axis represents the fuel-air equivalence ratio of the fuel to the air in the mixture supplied to the combustion chamber 21 a . Figure 9 In FIG. 1 , the relationship between the combustion temperature and the fuel-air equivalence ratio is shown as follows: the mapping of NO+NO2 contained in the exhaust gas of the engine device 1 is shown. As shown by the white arrow 60, the amount of NO+NO2 increases. Figure 9 The higher the combustion temperature, the more NO+NO2 will be produced.

[0090] Thus, according to other examples, control can be performed in the following manner: the emission ratio of nitrogen oxides in the exhaust gas is increased by performing at least one of a reduction in the EGR rate, an increase in the injection pressure of the auxiliary fuel, an increase in the intake bypass amount, an increase in the opening of the waste gate of the supercharger 51, and an increase in the opening of the variable nozzle of the supercharger 51, so that the emission ratio of nitrogen oxides reaches a specified ratio.

[0091] On the other hand, in yet another example, the engine device 1 is configured to, in addition to or instead of the above-mentioned excess air ratio of the mixture, the injection timing of the auxiliary fuel, and the mixing ratio of the main fuel, be controlled in the following manner: the emission ratio of unburned ammonia in the exhaust gas and the emission ratio of nitrogen oxides is increased by increasing the EGR rate of the recirculation device 53, increasing the injection pressure of the auxiliary fuel of the auxiliary fuel injection portion 26, reducing the amount of air bypassed from the intake passage 3 to the exhaust passage 4 on the intake bypass passage 54 (i.e., the intake bypass amount), reducing the opening of the waste gate 55 of the supercharger 51, and reducing the opening of the variable nozzle 51c of the supercharger 51, so as to increase the emission ratio of unburned ammonia in the exhaust gas and the emission ratio of nitrogen oxides, so that the emission ratio of unburned ammonia reaches a specified target ratio (specified ratio).

[0092] Specifically, the engine device 1 controls the recirculation valve 53c of the recirculation device 53 via the control device 9 to increase the ratio of exhaust gas recirculated from the exhaust passage 4 to the intake passage 3 through the recirculation device 53, that is, the EGR rate. Consequently, control is performed such that the combustion temperature within the combustion chamber 21a decreases by increasing the exhaust gas recirculated into the intake air, thereby increasing the emission ratio of unburned ammonia in the exhaust gas and achieving a predetermined target ratio (predetermined ratio).

[0093] Alternatively, the engine device 1 controls the auxiliary fuel injection unit 26 via the control device 9 to reduce the injection pressure of the auxiliary fuel injected into the combustion chamber 21a. In this manner, control is performed such that the combustion temperature in the combustion chamber 21a is lowered by the combustion of the auxiliary fuel having the reduced injection pressure, thereby increasing the emission ratio of unburned ammonia in the exhaust gas until the emission ratio of unburned ammonia reaches a predetermined target ratio.

[0094] Alternatively, the engine device 1 controls the intake bypass valve 54a via the control device 9 to reduce the amount of intake bypass air flowing into the exhaust passage 4. In this manner, control is performed such that the proportion of air in the intake air is increased and the proportion of fuel is decreased, thereby lowering the combustion temperature in the combustion chamber 21a and increasing the discharge ratio of unburned ammonia in the exhaust gas, so that the discharge ratio of unburned ammonia reaches a predetermined target ratio.

[0095] Alternatively, the engine device 1 controls the wastegate valve 55a via the control device 9 to reduce the opening of the wastegate 55. In this manner, the engine device 1 is controlled such that the ratio of air in the intake air is increased by reducing the amount of residual gas, the air compression rate of the supercharger 51 is increased, and the ratio of fuel is reduced, thereby lowering the combustion temperature in the combustion chamber 21a and increasing the emission ratio of unburned ammonia in the exhaust gas, so that the emission ratio of unburned ammonia reaches a predetermined target ratio.

[0096] Alternatively, the engine device 1 controls the variable nozzle 51c via the control device 9 to reduce the opening of the variable nozzle 51c, thereby reducing the passage area of ​​the turbine 51a of the supercharger 51. In this manner, the engine device 1 is controlled such that the amount of residual gas is reduced, the amount of air compression in the supercharger 51 is increased, the proportion of air in the intake air is increased, and the proportion of fuel is reduced, thereby lowering the combustion temperature in the combustion chamber 21a and increasing the emission ratio of unburned ammonia in the exhaust gas, so that the emission ratio of unburned ammonia reaches a predetermined target ratio.

[0097] Figure 10 In FIG. 2 , the horizontal axis represents the combustion temperature in the combustion chamber 21 a , and the vertical axis represents the fuel-air equivalence ratio of the fuel to the air in the mixture supplied to the combustion chamber 21 a . Figure 10 In FIG. 1 , the relationship between the combustion temperature and the fuel-air equivalence ratio is shown as follows: the map of unburned ammonia contained in the exhaust gas of the engine device 1 shows that the unburned ammonia increases in the direction indicated by the white arrow 61. Figure 10 , the lower the combustion temperature, the more unburned ammonia there will be.

[0098] Thus, according to other examples, control can be performed in the following manner: the emission ratio of unburned ammonia in the exhaust gas is increased by performing at least one of an increase in the EGR rate, a decrease in the injection pressure of the auxiliary fuel, a decrease in the intake bypass amount, a decrease in the exhaust valve opening of the supercharger 51, and a decrease in the variable nozzle opening of the supercharger 51, so that the emission ratio of unburned ammonia reaches a specified ratio.

[0099] Furthermore, the present invention may be appropriately modified without departing from the spirit or concept of the invention as can be read from the claims and the entire contents of the specification, and an ammonia co-firing engine with such modifications is also included in the technical concept of the present invention.

[0100] [Supplementary Notes on the Invention]

[0101] The following is a summary of the invention extracted from the above-mentioned embodiment as a supplementary note. In addition, each configuration and each processing function described in the following supplementary notes can be selected and discarded, and can be combined arbitrarily.

[0102] Note 1

[0103] An engine device is an ammonia co-firing engine device that operates by burning a main fuel containing ammonia and a hydrocarbon-based auxiliary fuel. The engine device is characterized in that at least one of the excess air ratio of the mixture of the main fuel and air and the injection period of the auxiliary fuel is controlled in such a manner that the emission ratio of unburned ammonia and nitrogen oxides contained in the generated exhaust gas reaches a specified ratio.

[0104] Note 2

[0105] An engine device is an ammonia co-firing engine device that operates by burning a main fuel containing ammonia and a secondary fuel of a hydrocarbon system. It is characterized in that hydrogen is mixed with the ammonia to generate the main fuel, and the mixing ratio of the ammonia and hydrogen in the main fuel is controlled in such a way that the emission ratio of unburned ammonia and nitrogen oxides contained in the exhaust gas reaches a specified ratio.

[0106] Note 3

[0107] An engine device is an ammonia co-firing engine device that operates by burning a main fuel containing ammonia and a hydrocarbon-based auxiliary fuel. It is characterized in that hydrogen is mixed with the ammonia to generate the main fuel, and at least one of the excess air ratio of the mixture of the main fuel and air, the injection period of the auxiliary fuel, and the mixing ratio of the ammonia and hydrogen in the main fuel are controlled in such a way that the emission ratio of unburned ammonia and nitrogen oxides contained in the exhaust gas reaches a specified ratio.

[0108] Note 4

[0109] Based on the engine device described in Appendix 3, it is characterized in that control is performed in the following manner: the emission ratio of unburned ammonia in the exhaust gas and the emission ratio of nitrogen oxides are increased by increasing at least one of increasing or decreasing the excess air ratio, delaying the injection period, and increasing the mixing ratio of ammonia, so that the emission ratio of unburned ammonia reaches the specified ratio.

[0110] Note 5

[0111] Based on the engine device described in Note 3 or 4, it is characterized in that control is performed in the following manner: the emission ratio of the unburned ammonia in the exhaust gas and the emission ratio of the nitrogen oxides are increased by at least one of increasing or decreasing the excess air ratio, advancing the injection period, and increasing the mixing ratio of the hydrogen, so that the emission ratio of the nitrogen oxides reaches the specified ratio.

[0112] <Note 6>

[0113] The engine device according to any one of Supplementary Notes 1 to 5 is characterized in that the engine device includes a selective reduction catalyst for reducing the nitrogen oxides contained in the exhaust gas using a reducing agent, and an ammonia adsorption catalyst for adsorbing the unburned ammonia contained in the exhaust gas.

[0114] <Note 7>

[0115] In the engine device according to any one of Supplementary Notes 2 to 5, the hydrogen gas is generated by reforming the ammonia.

[0116] <Note 8>

[0117] Based on the engine device described in Appendix 3, it is characterized in that the emission ratio of the unburned ammonia in the exhaust gas and the emission ratio of the nitrogen oxides are increased by at least one of reducing the EGR rate, increasing the injection pressure of the auxiliary fuel, increasing the intake bypass amount, increasing the exhaust valve opening of the supercharger, and increasing the variable nozzle opening of the supercharger, so that the emission ratio of the nitrogen oxides reaches the specified ratio.

[0118] <Note 9>

[0119] Based on the engine device described in Appendix 3, it is characterized in that the emission ratio of the unburned ammonia in the exhaust gas and the emission ratio of the nitrogen oxides are increased by at least one of increasing the EGR rate, reducing the injection pressure of the auxiliary fuel, reducing the intake bypass amount, reducing the exhaust valve opening of the supercharger, and reducing the variable nozzle opening of the supercharger, so that the emission ratio of the unburned ammonia reaches the specified ratio.

Claims

1. An engine device, which is an ammonia co-firing engine device that operates by burning a main fuel containing ammonia and a hydrocarbon-based auxiliary fuel, characterized in that: At least one of the excess air ratio of the mixture of the main fuel and air and the injection timing of the auxiliary fuel is controlled so that the emission ratio of unburned ammonia and nitrogen oxides contained in the exhaust gas reaches a predetermined ratio.

2. An engine device that is an ammonia co-firing engine device that operates by burning a main fuel containing ammonia and a hydrocarbon-based auxiliary fuel, characterized in that: mixing the hydrogen with the ammonia to generate the primary fuel, The mixing ratio of the ammonia and the hydrogen in the main fuel is controlled so that the emission ratio of unburned ammonia and nitrogen oxides contained in the exhaust gas reaches a predetermined ratio.

3. An engine device, which is an ammonia co-firing engine device that operates by burning a main fuel containing ammonia and a hydrocarbon-based auxiliary fuel, characterized in that: mixing the hydrogen with the ammonia to generate the primary fuel, At least one of the excess air ratio of the mixture of the main fuel and air, the injection timing of the auxiliary fuel, and the mixing ratio of the ammonia and hydrogen in the main fuel is controlled so that the emission ratio of unburned ammonia and nitrogen oxides contained in the exhaust gas reaches a predetermined ratio.

4. The engine device according to claim 3, characterized in that Control is performed in the following manner: the emission ratio of unburned ammonia in the exhaust gas and the emission ratio of nitrogen oxides are increased by increasing at least one of increasing or decreasing the excess air ratio, delaying the injection period, and increasing the mixing ratio of ammonia, so that the emission ratio of unburned ammonia reaches the specified ratio.

5. The engine device according to claim 3, characterized in that Control is performed in the following manner: the emission ratio of the unburned ammonia in the exhaust gas and the nitrogen oxides in the emission ratio of the nitrogen oxides are increased by at least one of increasing or decreasing the excess air ratio, advancing the injection period, and increasing the mixing ratio of the hydrogen, so that the emission ratio of the nitrogen oxides reaches the specified ratio.

6. The engine device according to any one of claims 1 to 3, characterized in that: The engine device includes a selective reduction catalyst for reducing the nitrogen oxides contained in the exhaust gas using a reducing agent, and an ammonia adsorption catalyst for adsorbing the unburned ammonia contained in the exhaust gas.

7. The engine device according to claim 2 or 3, characterized in that: The ammonia is reformed to generate the hydrogen.

8. The engine device according to claim 3, characterized in that The control is performed as follows: the emission ratio of the unburned ammonia in the exhaust gas and the nitrogen oxides in the nitrogen oxides are increased by at least one of reducing the EGR rate, increasing the injection pressure of the auxiliary fuel, increasing the intake bypass amount, increasing the opening of the waste gate of the supercharger, and increasing the opening of the variable nozzle of the supercharger, so that the emission ratio of the nitrogen oxides reaches the specified ratio.

9. The engine device according to claim 3, characterized in that The control is performed as follows: the emission ratio of unburned ammonia in the exhaust gas and the emission ratio of nitrogen oxides is increased by performing at least one of an increase in the EGR rate, a decrease in the injection pressure of the auxiliary fuel, a decrease in the intake bypass amount, a decrease in the opening of the waste gate of the supercharger, and a decrease in the opening of the variable nozzle of the supercharger, so that the emission ratio of unburned ammonia reaches the specified ratio.

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