JP2022026678A - Engine system - Google Patents

Abstract

To provide an engine system capable of shortening a starting time of a reformer.SOLUTION: An engine system 1 includes: an injector 5 injecting ammonia gas toward inside of a cylinder 7 of an ammonia engine 2; a throttle valve 6 controlling a flow rate of air to be supplied into the cylinder 7; a reformer 17 reforming ammonia gas by using heat generated by burning the ammonia gas; a fuel supply part 26 supplying ammonia gas to the reformer 17; an air supply part 27 supplying air to the reformer 17; a reformed gas flow passage 22 in which reformed gas generated by the reformer 17 flows toward inside of the cylinder 7; a combustor 28 generating combustion gas to be supplied to the reformer 17; a starting gas flow passage 36 in which starting gas obtained by mixing the ammonia gas and air in the cylinder 7 flows toward the combustor 28; and a starting valve 37 adjusting a flow of the starting gas in the starting gas flow passage 36.SELECTED DRAWING: Figure 1

Description

The present invention relates to an engine system.

As a conventional engine system, for example, the technique described in Patent Document 1 is known. The engine system described in Patent Document 1 includes an engine body, an intake path and an exhaust path connected to the combustion chamber of the engine body, and a throttle provided in the intake path to adjust the amount of air introduced into the combustion chamber. It is equipped with a fuel supply unit that supplies ammonia as fuel to the combustion chamber of the engine body, and an ignition plug that ignites the ammonia in the combustion chamber and burns the ammonia. The fuel supply unit includes a fuel tank that stores ammonia, an evaporator that vaporizes the ammonia in the fuel tank, a first supply unit that supplies the ammonia vaporized by this evaporator to the combustion chamber, and an evaporator. It has an ammonia reformer that generates hydrogen gas by heating and decomposing the ammonia vaporized by the above, and a second supply unit that supplies the hydrogen generated by this ammonia reformer to the combustion chamber. is doing.

Japanese Unexamined Patent Publication No. 2019-178623

In the above-mentioned prior art, when the ammonia reformer is started, the catalyst of the ammonia reformer reacts with ammonia and oxygen, so that the ammonia ignites and burns. However, if it takes time to ignite the ammonia, the start-up time of the ammonia reformer becomes long.

An object of the present invention is to provide an engine system capable of shortening the start-up time of a reformer.

The engine system according to one aspect of the present invention includes an engine having pistons reciprocally arranged in the cylinder, an intake passage through which air supplied into the cylinder flows, and exhaust gas generated in the cylinder. A passage, a fuel injection valve that injects fuel gas into the cylinder, a flow control valve that is arranged in the intake passage and controls the flow rate of air supplied into the cylinder, and a starter that reciprocates the piston. A reformer that produces a reformed gas containing hydrogen by reforming the fuel gas using the heat generated by burning the fuel gas, and a fuel supply unit that supplies the fuel gas to the reformer. , An air supply unit that supplies air to the reformer, a reforming gas flow path through which the reforming gas generated by the reformer flows toward the inside of the cylinder, and a combustion gas supplied to the reformer are generated. A start-up gas flow path that connects the combustor, an exhaust passage, and a combustor, and a start-up gas in which fuel gas and air are mixed flows toward the combustor, and a start-up gas flow path for start-up in the start-up gas flow path. A starter gas regulator that adjusts the gas flow, and a starter, fuel injection valve, and flow control so that fuel gas and air are introduced into the cylinder and the starter gas is discharged from the cylinder when the engine is started. The first control unit that controls the valve, controls the starting gas adjustment unit so that the starting gas is supplied to the combustor, and controls the combustor so that the fuel gas in the starting gas ignites, and the first A second control unit that controls the fuel supply unit and the air supply unit so that the fuel gas and air are supplied to the reformer at the same time as the execution of the control process by the 1 control unit or after the control process by the first control unit is executed. The control unit and the third control unit that controls the start-up gas adjusting unit so that the supply of the start-up gas to the combustor is stopped after the control process by the first control unit and the second control unit is executed. Be prepared.

In such an engine system, when the engine is started, the fuel gas and air are introduced into the cylinder by the reciprocating movement of the piston arranged in the cylinder, and the fuel gas and air are mixed and started from the inside of the cylinder. Gas is discharged. Then, the starting gas flows through the starting gas flow path and is supplied to the combustor by the starting gas adjusting unit, and the fuel gas in the starting gas is ignited and burned in the combustor to generate combustion gas. Then, the combustion gas is supplied to the reformer, and the reformer is heated by the heat of the combustion gas. In addition, fuel gas and air are supplied to the reformer. Then, in the reformer, the fuel gas is burned and reformed to generate a reformed gas containing hydrogen. After that, the supply of starting gas to the combustor is stopped. The reforming gas generated by the reformer flows through the reforming gas flow path and is supplied into the cylinder of the engine. Then, in the cylinder, the fuel gas burns together with the hydrogen in the reformed gas. Since the fuel gas is burned and reformed in the reformer by utilizing the heat of the high-temperature combustion gas generated by burning the fuel gas by the combustor in this way, the time until the fuel gas ignites is performed. It gets shorter. This shortens the start-up time of the reformer.

Further, the fuel gas and air are introduced into the cylinder, and the starting gas mixed with the fuel gas and air is discharged from the cylinder, and the starting gas is supplied to the combustor. By using the fuel gas and air supplied in the cylinder of the engine to supply the starting gas to the combustor in this way, the gas supply dedicated to the combustor for supplying the fuel gas and air to the combustor is used. The part is unnecessary. Further, since the starting gas is pushed out from the cylinder by the piston and supplied to the combustor, the flow of the starting gas is stabilized, and the fuel gas in the starting gas is stably burned.

The engine system further includes an EGR passage that connects the exhaust passage and the intake passage, and a part of the exhaust gas flows toward the intake passage as EGR gas, and an EGR valve that controls the flow rate of the EGR gas flowing through the EGR passage. The starting gas flow path connects the exhaust passage and the combustor via the EGR passage by connecting the upstream side of the EGR valve in the EGR passage to the combustor, and the starting gas adjusting unit is started. It is a valve that opens and closes the exhaust gas flow path, and the first control unit may control to open the valve, and the third control unit may control to close the valve. In such a configuration, since the starting gas is supplied to the combustor from the inside of the cylinder of the engine by using the existing EGR device, the starting gas adjusting unit can be realized with a simple configuration.

The engine system further includes a temperature detection unit that detects the temperature of the reformer, and the third control unit is when the temperature of the reformer detected by the temperature detection unit is equal to or higher than a predetermined first specified temperature. In addition, the starting gas adjusting unit may be controlled so that the supply of the starting gas to the combustor is stopped. In such a configuration, when the temperature of the reformer becomes higher than the first specified temperature, the supply of the starting gas from the inside of the cylinder of the engine to the combustor is stopped. Therefore, it is prevented that the starting gas is unnecessarily supplied to the combustor.

The first specified temperature may be a temperature higher than the reformable temperature at which the reformer can reform the fuel gas. In such a configuration, even after the reforming gas is generated by the reformer, the starting gas is continuously supplied to the combustor from the inside of the cylinder of the engine for a certain period of time. Therefore, the reformed gas is supplied to the combustor from the inside of the cylinder together with the starting gas. Therefore, in the combustor, the hydrogen in the reforming gas is burned together with the fuel gas in the starting gas, so that the fuel gas in the starting gas is easily burned. This further shortens the start-up time of the reformer.

The engine system determines whether the fuel gas in the starting gas has ignited based on the temperature of the reformer detected by the temperature detector, and when the fuel gas in the starting gas ignites, the inside of the cylinder The fuel injection valve is controlled so that the introduction of the fuel gas into the cylinder is stopped, and then when the temperature of the reformer detected by the temperature detector is higher than the first specified temperature and higher than the second specified temperature, the cylinder A fourth control unit that controls the fuel injection valve so that the fuel gas is introduced again may be further provided therein. In such a configuration, when the fuel gas in the starting gas ignites, the introduction of the fuel gas into the cylinder of the engine is temporarily stopped. Therefore, it is prevented that the fuel gas is wasted.

The combustor has a circular tubular housing, a starting gas introduction part that introduces the starting gas so that a tubular flow is generated inside the housing, and a housing that is attached to the housing and is attached to the housing from the starting gas introduction part. It has an ignition unit for igniting the fuel gas in the starting gas introduced inside the above, and the first control unit may be controlled to ignite the ignition unit. In such a configuration, the starting gas is introduced into the inside of the circular tubular housing from the starting gas introduction portion. Then, when the ignition unit ignites, the fuel gas in the starting gas ignites and burns. At this time, the starting gas is introduced so as to generate a tubular flow inside the housing. Therefore, the fuel gas in the starting gas is ignited in a state where the starting gas is in a tubular flow to form a tubular flame, so that the combustion gas swirls and flows toward the reformer. Therefore, the fuel gas is stably burned in the reformer.

According to the present invention, the start-up time of the reformer can be shortened.

It is a schematic block diagram which shows the engine system which concerns on one Embodiment of this invention. It is a conceptual diagram of the ammonia engine shown in FIG. It is sectional drawing of the combustor shown in FIG. It is a control system block diagram of the engine system shown in FIG. It is a flowchart which shows the detail of the control processing procedure executed by the main controller shown in FIG. It is a timing diagram which shows the operation of the engine system when the control process shown in FIG. 5 is executed. It is a flowchart which shows the modification of the control processing procedure executed by the main controller shown in FIG. It is a timing diagram which shows the operation of the engine system when the control process shown in FIG. 7 is executed. It is a timing diagram which shows the modification of the operation of the engine system shown in FIG. It is a timing diagram which shows the other modification of the operation of the engine system shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are designated by the same reference numerals, and duplicate description will be omitted.

FIG. 1 is a schematic configuration diagram showing an engine system according to an embodiment of the present invention. In FIG. 1, the engine system 1 of the present embodiment includes an ammonia engine 2, an intake passage 3, an exhaust passage 4, an injector 5, and a throttle valve 6.

The ammonia engine 2 is an engine that uses ammonia gas ( _NH3 gas) as a fuel gas. In the ammonia engine 2, hydrogen is mixed with ammonia in order to facilitate combustion of ammonia gas. The ammonia engine 2 is, for example, a 4-cylinder engine.

As shown in FIG. 2, the ammonia engine 2 includes four cylinders 7 (cylinders 7A to 7D), four pistons 8 reciprocating within each cylinder 7, and each piston 8. It has four connecting rods 9 that each connect to a crankshaft (not shown). The space on the cylinder head (not shown) side of the piston 8 in the cylinder 7 is a combustion chamber 7a in which ammonia gas is burned.

Further, the ammonia engine 2 has an intake hole 10 and an exhaust hole 11 communicating with each combustion chamber 7a. The intake hole 10 is opened and closed by an electromagnetic intake valve 12 (see FIG. 4). The exhaust hole 11 is opened and closed by an electromagnetic exhaust valve 13 (see FIG. 4).

Further, the ammonia engine 2 has an ignition device 14. The ignition device 14 ignites the ammonia gas supplied to each combustion chamber 7a. The ignition device 14 is, for example, a spark plug provided for each cylinder 7.

The intake passage 3 is connected to the intake hole 10. The intake passage 3 is a passage through which air supplied to each combustion chamber 7a flows. The exhaust passage 4 is connected to the exhaust hole 11. The exhaust passage 4 is a passage through which the exhaust gas generated in each combustion chamber 7a flows.

The injector 5 is an electromagnetic fuel injection valve that injects ammonia gas, which is a fuel gas, toward each combustion chamber 7a. The injector 5 is provided for each cylinder 7. Here, the ammonia gas directly supplied to the combustion chamber 7a of the ammonia engine 2 by the injector 5 is used as the main ammonia gas.

The throttle valve 6 is arranged in the intake passage 3. The throttle valve 6 is an electromagnetic flow rate control valve that controls the flow rate of air supplied to each combustion chamber 7a. Here, the air directly supplied to the combustion chamber 7a of the ammonia engine 2 is used as the main air.

Further, the engine system 1 includes an ammonia tank 15, a vaporizer 16, a reformer 17, an ammonia flow path 18, an ammonia valve 19, an air flow path 20, an air valve 21, and a reforming gas flow path. It has 22 and.

The ammonia tank 15 is a tank that stores ammonia in a liquid state. That is, the ammonia tank 15 stores liquid ammonia. The vaporizer 16 vaporizes the liquid ammonia stored in the ammonia tank 15 to generate ammonia gas. The vaporizer 16 is connected to the injector 5 via the ammonia flow path 23. The ammonia flow path 23 is a flow path through which the ammonia gas supplied to the injector 5 flows.

The reformer 17 produces a reformed gas containing hydrogen by reforming the ammonia gas by utilizing the heat generated by burning the ammonia gas. The reformer 17 has a reforming catalyst 17a. The reforming catalyst 17a has a function of burning ammonia gas in addition to a function of decomposing ammonia gas into hydrogen. The reforming catalyst 17a is, for example, an ATR (Autothermal Reformer) type ammonia reforming catalyst. As the reforming catalyst 17a, for example, a cobalt-based catalyst, a rhodium-based catalyst, a ruthenium-based catalyst, a palladium-based catalyst, or the like is used.

The ammonia flow path 18 connects the vaporizer 16 and the reformer 17. The ammonia flow path 18 is a flow path through which the ammonia gas supplied to the reformer 17 flows. The ammonia valve 19 is arranged in the ammonia flow path 18. The ammonia valve 19 is an electromagnetic flow rate control valve that controls the flow rate of the ammonia gas supplied to the reformer 17.

The ammonia tank 15, the vaporizer 16, the ammonia flow path 18, and the ammonia valve 19 constitute a fuel supply unit 26 that supplies ammonia gas to the reformer 17. Here, the ammonia gas supplied to the reformer 17 is used as the reforming ammonia gas.

The air flow path 20 connects the intake passage 3 and the reformer 17. The air flow path 20 is a flow path through which the air supplied to the reformer 17 flows. The air valve 21 is arranged in the air flow path 20. The air valve 21 is an electromagnetic flow rate control valve that controls the flow rate of air supplied to the reformer 17. The air flow path 20 and the air valve 21 constitute an air supply unit 27 that supplies air to the reformer 17. Here, the air supplied to the reformer 17 is used as the reforming air.

The reforming gas flow path 22 connects the reformer 17 and the intake passage 3. The reformed gas flow path 22 is a flow path through which the reformed gas generated by the reformer 17 flows toward the combustion chamber 7a of the ammonia engine 2.

Further, the engine system 1 includes a combustor 28. The combustor 28 is a tubular flame burner that generates combustion gas supplied to the reformer 17.

The combustor 28 is connected to the reformer 17 via a combustion gas flow path 29. The combustion gas flow path 29 is a flow path through which the combustion gas generated by the combustor 28 flows toward the reformer 17. The ammonia flow path 18 and the air flow path 20 are connected to the combustion gas flow path 29. The air flow path 20 is connected to the downstream side (reformer 17 side) of the ammonia flow path 18 in the combustion gas flow path 29.

As shown in FIG. 3, the combustor 28 is attached to a circular tubular housing 30, a plurality of (here, four) starting gas introduction portions 31 provided in the housing 30, and a housing 30. It has an ignition unit 32 (see FIG. 4). The housing 30 may be integrated with a pipe forming the combustion gas flow path 29.

The starting gas introduction unit 31 introduces the starting gas for generating the combustion gas so as to generate a tubular flow inside the housing 30. Specifically, the starting gas introduction unit 31 introduces the starting gas into the housing 30 in the tangential direction of the inner peripheral surface 30a of the housing 30. The starting gas is a gas containing ammonia gas and air. The starting gas may contain a small amount of gas other than ammonia gas and air.

The ignition unit 32 ignites the ammonia gas in the starting gas introduced into the housing 30 from the starting gas introducing unit 31. The ignition unit 32 is fixed to the tip of the housing 30. The ignition unit 32 is, for example, a glow plug or a spark plug.

Further, the engine system 1 includes an EGR device 35, a starting gas flow path 36, and a starting valve 37.

The EGR device 35 recirculates a part of the exhaust gas generated in each combustion chamber 7a of the ammonia engine 2 as EGR gas (exhaust gas recirculation gas). The EGR device 35 has an EGR passage 38 connecting the exhaust passage 4 and the intake passage 3, and an EGR valve 39 and an EGR cooler 40 arranged in the EGR passage 38.

The EGR passage 38 is a passage through which EGR gas flows from the exhaust passage 4 toward the intake passage 3. The EGR valve 39 is an electromagnetic flow rate adjusting valve that adjusts the flow rate of the EGR gas flowing through the EGR passage 38. The EGR cooler 40 cools the EGR gas flowing through the EGR passage 38. The EGR valve 39 is arranged on the downstream side of the EGR cooler 40 in the EGR passage 38.

The starting gas flow path 36 connects the exhaust passage 4 and the combustor 28. Specifically, one end of the starting gas flow path 36 is connected between the EGR cooler 40 and the EGR valve 39 in the EGR passage 38. That is, one end of the starting gas flow path 36 is connected to a portion of the EGR passage 38 on the upstream side of the EGR valve 39. The other end of the starting gas flow path 36 is connected to each starting gas introduction portion 31 of the combustor 28. The starting gas flow path 36 is a flow path in which the starting gas, which is a mixture of ammonia gas and air, flows toward the combustor 28 in the combustion chamber 7a of the ammonia engine 2.

The starting valve 37 is arranged in the starting gas flow path 36. The start-up valve 37 is an electromagnetic on-off valve (ON / OFF valve) that opens and closes the start-up gas flow path 36. The starting valve 37 constitutes a starting gas adjusting unit that adjusts the flow of starting gas in the starting gas flow path 36. The starting valve 37 may be a flow rate adjusting valve.

Further, the engine system 1 includes a starter 41, a temperature sensor 42, an engine ECU 43, and a main controller 44.

The starter 41 is a motor for starting the ammonia engine 2. The starter 41 reciprocates the pistons 8 arranged in each cylinder 7 via the connecting rod 9 by rotating the crankshaft (not shown) of the ammonia engine 2.

The temperature sensor 42 is a temperature detection unit that detects the temperature of the reformer 17. The temperature sensor 42 may detect, for example, the temperature of the reforming catalyst 17a of the reformer 17, or may detect the temperature of the reforming ammonia gas supplied to the reformer 17.

The engine ECU 43 is composed of a CPU, RAM, ROM, an input / output interface, and the like. The engine ECU 43 is an ECU (electronic control unit) that controls the ammonia engine 2.

Specifically, as shown in FIG. 4, the engine ECU 43 takes in the intake valve 12 of the ammonia engine 2 so that the four strokes of the intake stroke, the compression stroke, the expansion stroke (combustion stroke), and the exhaust stroke form one cycle. , Controls the exhaust valve 13 and the ignition device 14. The engine ECU 43 controls to open the intake valve 12 in the intake stroke. The engine ECU 43 controls the ignition device 14 to be ignited in the expansion stroke. The engine ECU 43 controls to open the exhaust valve 13 in the exhaust stroke.

At this time, as shown in FIG. 2, the engine ECU 43 controls the intake valve 12, the exhaust valve 13, and the ignition device 14 so as to burn the main ammonia gas in the order of the cylinders 7A, 7C, 7D, and 7B.

The main controller 44 is composed of a CPU, RAM, ROM, an input / output interface, and the like. As shown in FIG. 4, the main controller 44 outputs a control signal for controlling the intake valve 12, the exhaust valve 13, and the ignition device 14 to the engine ECU 43 based on the operation signal of the ignition switch (not shown). do. Further, the main controller 44 has an injector 5, a throttle valve 6, a starter 41, an ammonia valve 19 of the fuel supply unit 26, and an air supply based on an operation signal of an ignition switch (not shown) and a detected value of the temperature sensor 42. It controls the air valve 21 of the unit 27, the ignition unit 32 of the combustor 28, the starting valve 37, and the EGR valve 39.

The main controller 44 has a first control unit 45, a second control unit 46, a third control unit 47, and a fourth control unit 48.

When the ammonia engine 2 is started, the first control unit 45 introduces the main ammonia gas and the main air into the cylinder 7, and discharges the starting gas in which the main ammonia gas and the main air are mixed from the inside of the cylinder 7. The starter 41, the injector 5, and the throttle valve 6 are controlled in this manner. Further, the first control unit 45 controls the start valve 37 so that the start gas is supplied to the combustor 28, and controls the ignition unit 33 so that the main ammonia in the start gas ignites.

The second control unit 46 controls the ammonia valve 19 and the air valve 21 so that the reforming ammonia gas and the reforming air are supplied to the reformer 17 at the same time as the execution of the control process by the first control unit 45. do. It should be noted that the simultaneousness referred to here is not limited to the perfect simultaneousness. For example, there is a case where the control process by the first control unit 45 is executed slightly before the timing of execution.

The third control unit 47 controls the start valve 37 so that the supply of the start gas to the combustor 28 is stopped after the control process by the first control unit 45 and the second control unit 46 is executed. The third control unit 47 stops the supply of the starting gas to the combustor 28 when the temperature of the reformer 17 detected by the temperature sensor 42 is equal to or higher than the predetermined first predetermined temperature. The starting valve 37 is controlled.

The fourth control unit 48 determines whether or not the main ammonia gas in the starting gas has ignited based on the temperature of the reformer 17 detected by the temperature sensor 42, and the main ammonia gas in the starting gas ignites. At that time, the injector 5 is controlled so that the introduction of the main ammonia gas into the cylinder 7 is stopped. Then, when the temperature of the reformer 17 detected by the temperature sensor 42 is equal to or higher than the second specified temperature higher than the first specified temperature, the fourth control unit 48 reintroduces the main ammonia gas into the cylinder 7. The injector 5 is controlled so as to be operated.

FIG. 5 is a flowchart showing details of the control processing procedure executed by the main controller 44. This process is executed when the ignition switch (not shown) is turned on. Before the execution of this process, the injector 5, the throttle valve 6, the ammonia valve 19, the air valve 21, the starting valve 37, and the EGR valve 39 are in the closed state.

In FIG. 5, the main controller 44 first rotationally drives the starter 41 (procedure S101). Then, in the ammonia engine 2, the crankshaft (not shown) rotates and each piston 8 reciprocates. Further, the main controller 44 controls to open the starting valve 37 (procedure S102).

Further, the main controller 44 controls to open the injector 5 and the throttle valve 6 (procedure S103). Then, the main ammonia gas and the main air are introduced into each cylinder 7 of the ammonia engine 2. Then, the starting gas in which the main ammonia gas and the main air are mixed is discharged from the inside of the cylinder 7. Then, the starting gas flows through the starting gas flow path 36 and is supplied to the combustor 28. The main controller 44 may control the injector 5 to open intermittently according to the timing at which the intake valve 12 opens.

Subsequently, the main controller 44 controls to ignite the ignition unit 32 of the combustor 28 (procedure S104). Then, the main ammonia gas in the starting gas is ignited in the combustor 28.

Subsequently, the main controller 44 controls to open the ammonia valve 19 and the air valve 21 (procedure S105). Then, the reforming ammonia gas and the reforming air are supplied to the reformer 17.

Subsequently, the main controller 44 acquires the detected value of the temperature sensor 42 (procedure S106). Then, the main controller 44 determines whether or not the combustion of the main ammonia gas in the starting gas has started based on the detection value of the temperature sensor 42 (procedure S107). At this time, the main controller 44 determines that the combustion of the main ammonia gas in the starting gas has started, for example, when the temperature of the reformer 17 rises by a predetermined temperature.

When the main controller 44 determines that the combustion of the main ammonia gas in the starting gas has not started, the procedure S106 is executed again. When the main controller 44 determines that the combustion of the main ammonia gas in the starting gas has started, the main controller 44 controls to stop the ignition of the ignition unit 32 of the combustor 28 (procedure S108).

Subsequently, the main controller 44 acquires the detected value of the temperature sensor 42 (procedure S109). Then, the main controller 44 determines whether or not the temperature of the reformer 17 is equal to or higher than the predetermined predetermined temperature T1 based on the detection value of the temperature sensor 42 (procedure S110). The specified temperature T1 is a reformable temperature at which ammonia gas can be reformed by the reforming catalyst 17a of the reformer 17. Here, the specified temperature T1, which is the reformable temperature, corresponds to the above-mentioned first specified temperature.

When the main controller 44 determines that the temperature of the reformer 17 is not equal to or higher than the specified temperature T1, the main controller 44 re-executes the procedure S109. When the main controller 44 determines that the temperature of the reformer 17 is equal to or higher than the specified temperature T1, the main controller 44 controls to close the injector 5 (procedure S111). Then, the supply of the main ammonia gas into each cylinder 7 of the ammonia engine 2 is stopped. Further, the main controller 44 controls to close the starting valve 37 (procedure S112).

Subsequently, the main controller 44 acquires the detected value of the temperature sensor 42 (procedure S113). Then, the main controller 44 determines whether or not the temperature of the reformer 17 is equal to or higher than the predetermined predetermined temperature T2 based on the detection value of the temperature sensor 42 (procedure S114). The specified temperature T2 is a temperature higher than the specified temperature T1. The specified temperature T2 is, for example, a temperature such that the amount of hydrogen produced by the reformer 17 is an amount N (see FIG. 6) suitable for combustion of the main ammonia gas by the ammonia engine 2, and is the above-mentioned second specification. Corresponds to temperature.

When the main controller 44 determines that the temperature of the reformer 17 is not equal to or higher than the specified temperature T2, the main controller 44 re-executes the procedure S113. When the main controller 44 determines that the temperature of the reformer 17 is equal to or higher than the specified temperature T2, the main controller 44 controls the injector 5 to open (procedure S115). Then, the main ammonia gas is supplied into each cylinder 7 of the ammonia engine 2.

Then, the main controller 44 sends a control signal for igniting the ignition device 14 to the engine ECU 43 (procedure S116). Then, the ignition device 14 can be ignited. After that, the main controller 44 controls to stop the rotation of the starter 41 after the start of the ammonia engine 2 is completed (procedure S117).

In the above, the first control unit 45 executes the procedures S101 to S104. The second control unit 46 executes the procedure S105. The third control unit 47 executes the procedures S109, S110, and S112. The fourth control unit 48 executes the procedures S106, S107, S111, and S113 to S115.

In the engine system 1 as described above, when the ignition switch (not shown) is turned on, the starter 41 is rotationally driven as shown in FIG. 6A. Then, in the ammonia engine 2, the crankshaft (not shown) rotates, and the piston 8 reciprocates via the connecting rod 9.

Further, as shown in FIG. 6 (e), the starting valve 37 is opened. Further, as shown in FIGS. 6 (b) and 6 (c), the main ammonia gas and the main air are supplied to the combustion chamber 7a of the ammonia engine 2 by opening the injector 5 and the throttle valve 6.

Further, as shown in FIGS. 6 (g) and 6 (h), when the ammonia valve 19 and the air valve 21 are opened, the reforming ammonia gas and the reforming air are supplied to the reformer 17. .. Then, the reforming ammonia gas and the reforming air flow through the reformer 17, the reforming gas flow path 22, and the intake passage 3 and are supplied to the combustion chamber 7a of the ammonia engine 2.

At this time, in the intake stroke of the ammonia engine 2, the main ammonia gas, the main air, the reforming ammonia gas and the reforming air are sucked into the combustion chamber 7a by the piston 8. Then, in the compression stroke and the expansion stroke of the ammonia engine 2, the main ammonia gas and the reforming ammonia gas in the combustion chamber 7a are mixed with the main air and the reforming air. Then, in the exhaust stroke of the ammonia engine 2, the starting gas in which the main ammonia gas and the reforming ammonia gas and the main air and the reforming air are mixed is pushed out from the combustion chamber 7a by the piston 8 and discharged.

Each cylinder 7 carries out a different stroke at the same timing as described above. For example, as shown in FIG. 2, the exhaust stroke is carried out in the cylinder 7B, so that the intake stroke is carried out in the cylinder 7D when the starting gas in which ammonia gas and air are mixed is pushed out from the combustion chamber 7a. As a result, ammonia gas and air are sucked into the combustion chamber 7a.

The starting gas discharged from the combustion chamber 7a flows through the exhaust passage 4, the EGR passage 38, and the starting gas flow path 36, and is supplied to the combustor 28. The starting gas is introduced into the housing 30 from the starting gas introduction unit 31 in the combustor 28. At this time, since the starting gas is introduced into the housing 30 in the tangential direction of the inner peripheral surface 30a of the housing 30, it becomes a tubular flow inside the housing 30.

Further, as shown in FIG. 6 (f), when the ignition unit 32 of the combustor 28 ignites, the ammonia gas in the starting gas is ignited to form a tubular flame, and the ammonia gas begins to burn. Specifically, as shown in the following formula, ammonia and oxygen in the air chemically react to generate high-temperature combustion gas (exothermic reaction). The combustion gas swirls through the combustion gas flow path 29 toward the reformer 17 and flows.
NH ₃ + 3/4O ₂ → 1 / 2N ₂ + 3 / 2H ₂ O… (A)

At this time, the reciprocating motion of the piston 8 causes the ammonia engine 2 to function as a pump. Due to the pumping action of the ammonia engine 2, the ammonia engine 2, the exhaust passage 4, the EGR passage 38, the starting gas flow path 36, the combustor 28, the combustion gas flow path 29, the reformer 17, and the reforming gas flow path Gas circulates in 22 and the intake passage 3.

When the high-temperature combustion gas is supplied to the reformer 17, the reformer 17 is directly heated by the heat of the combustion gas. Further, the heat of the combustion gas heats the ammonia gas and air, and the heat of the ammonia gas and air also heats the reformer 17. Therefore, as shown in FIG. 6 (i), the temperature of the reformer 17 begins to rise. Then, as shown in FIG. 6 (f), the ignition of the ignition unit 32 of the combustor 28 is stopped.

After that, when the temperature of the reformer 17 reaches the combustible temperature, the ammonia gas is burned by the reforming catalyst 17a of the reformer 17. Then, the exothermic reaction of the above formula (A) occurs, and the combustion gas is generated in the reformer 17. Then, the temperature of the reformer 17 further rises due to the heat of the combustion gas. That is, the reformer 17 will perform an autonomous combustion operation.

After that, when the temperature of the reformer 17 reaches the specified temperature T1 which is the reformable temperature, the ammonia gas is reformed by the reforming catalyst 17a of the reformer 17. Specifically, as shown in the following formula, a decomposition reaction of ammonia occurs (endothermic reaction), and as shown in FIG. 6 (j), a reformed gas containing hydrogen is generated. The reformed gas flows through the reformed gas flow path 22 and the intake passage 3 and is supplied to the combustion chamber 7a of the ammonia engine 2.
NH ₃ → 3 / 2H ₂ + 1 / 2N ₂ … (B)

Further, when the temperature of the reformer 17 reaches the reformable temperature, the injector 5 closes the valve as shown in FIG. 6B, so that the main ammonia gas to the combustion chamber 7a of the ammonia engine 2 is charged. Supply will stop. Further, as shown in FIG. 6E, when the starting valve 37 is closed, the supply of the starting gas to the combustor 28 is stopped.

After that, when the temperature of the reformer 17 reaches the specified temperature T2, as shown in FIG. 6B, the injector 5 opens to supply the main ammonia gas to the combustion chamber 7a of the ammonia engine 2 again. Will be done. At this time, by adjusting the opening degrees of the injector 5 and the throttle valve 6, an appropriate amount of main ammonia gas and main air are supplied to the combustion chamber 7a. Then, when the ignition device 14 ignites, the main ammonia gas shifts to a steady state in which it burns together with hydrogen in the reformed gas.

As described above, in the present embodiment, when the ammonia engine 2 is started, the main ammonia gas and the main air are introduced into the cylinder 7 by the reciprocating movement of the piston 8 arranged in the cylinder 7, and the cylinder. Starting gas, which is a mixture of main ammonia gas and main air, is discharged from the inside of 7. Then, the starting gas flows through the starting gas flow path 36 and is supplied to the combustor 28 by the starting valve 37, and the main ammonia gas in the starting gas is ignited and burned in the combustor 28 to generate combustion gas. Will be done. Then, the combustion gas is supplied to the reformer 17, and the reformer 17 is heated by the heat of the combustion gas. Further, the reformer 17 is supplied with reforming ammonia gas and reforming air. Then, in the reformer 17, the reforming ammonia gas is burned and reformed to generate a reforming gas containing hydrogen. After that, the supply of the starting gas to the combustor 28 is stopped. The reforming gas generated by the reformer 17 flows through the reforming gas flow path 22 and is supplied into the cylinder 7 of the ammonia engine 2. Then, in the cylinder 7, the main ammonia gas burns together with the hydrogen in the reformed gas. Since the reformer 17 burns and reforms the reforming ammonia gas by utilizing the heat of the high-temperature combustion gas generated by burning the main ammonia gas by the combustor 28 in this way, it is used for reforming. The time it takes for ammonia gas to ignite is shortened. As a result, the start-up time of the reformer 17 is shortened.

Further, the main ammonia gas and the main air are introduced into the cylinder 7, and the starting gas in which the main ammonia gas and the main air are mixed is discharged from the cylinder 7, and the starting gas is supplied to the combustor 28. .. In order to supply the ammonia gas and air to the combustor 28 by using the main ammonia gas and the main air supplied into the cylinder 7 of the ammonia engine 2 in order to supply the starting gas to the combustor 28 in this way. There is no need for a gas supply unit dedicated to the combustor. Further, since the starting gas is pushed out from the cylinder 7 by the piston 8 and supplied to the combustor 28, the flow of the starting gas is stabilized, and the main ammonia gas in the starting gas is stably burned. ..

Further, in the present embodiment, the starting gas flow path 36 connects the exhaust passage 4 and the combustor 28 to the EGR passage 38 by connecting the upstream side of the EGR passage 38 to the upstream side of the EGR valve 39 and the combustor 28. Connected via, the starting valve 37 opens and closes the starting gas flow path 36. Therefore, since the starting gas is supplied to the combustor 28 from the inside of the cylinder 7 of the ammonia engine 2 by using the existing EGR device 35, the starting gas for adjusting the flow of the starting gas in the starting gas flow path 36 is adjusted. The gas adjustment unit can be realized with a simple configuration.

Further, in the present embodiment, when the temperature of the reformer 17 becomes the specified temperature T1 or higher, the supply of the starting gas from the ammonia engine 2 to the combustor 28 is stopped. Therefore, it is prevented that the starting gas is unnecessarily supplied to the combustor 28.

Further, in the present embodiment, when the main ammonia gas in the starting gas ignites, the supply of the main ammonia gas into the cylinder 7 of the ammonia engine 2 is temporarily stopped. Therefore, it is prevented that the main ammonia gas is wasted.

Further, in the present embodiment, in the combustor 28, the starting gas is introduced into the tubular housing 30 from the starting gas introducing portion 31. Then, when the ignition unit 32 ignites, the main ammonia in the starting gas is ignited and burned. At this time, the starting gas is introduced so as to generate a tubular flow inside the housing 30. Therefore, in a state where the starting gas is in a tubular flow, the main ammonia gas in the starting gas ignites to form a tubular flame, so that the combustion gas swirls and flows toward the reformer 17. Therefore, the reforming ammonia gas is stably burned in the reformer 17.

Further, in the present embodiment, when the ammonia engine 2 is started, the main ammonia gas introduced into the cylinder 7 of the ammonia engine 2 by the injector 5 is supplied to the combustor 28 and burned, so that the main ammonia gas is exhausted from the ammonia engine 2. The amount of the main ammonia gas passing through to the downstream side of the passage 4 is reduced.

FIG. 7 is a flowchart showing a modified example of the control processing procedure executed by the main controller 44, and corresponds to FIG.

In FIG. 7, the main controller 44 acquires the detection value of the temperature sensor 42 after executing the above procedures S101 to S111 (procedure S120). Then, the main controller 44 determines whether or not the temperature of the reformer 17 is equal to or higher than the predetermined predetermined temperature T3 based on the detection value of the temperature sensor 42 (procedure S121). As shown in FIG. 8, the specified temperature T3 is a temperature higher than the specified temperature T1 corresponding to the reformable temperature and lower than the specified temperature T2. Here, the specified temperature T3, not the specified temperature T1, corresponds to the above-mentioned first specified temperature.

When the main controller 44 determines that the temperature of the reformer 17 is not equal to or higher than the specified temperature T3, the main controller 44 executes the procedure S120 again. When the main controller 44 determines that the temperature of the reformer 17 is equal to or higher than the specified temperature T3, the main controller 44 controls to close the starting valve 37 (procedure S112). Then, the main controller 44 executes the above steps S113 to S118.

In such an embodiment, even after the reformer gas is generated by the reformer 17, the starting gas is continuously supplied to the combustor 28 from the cylinder 7 of the ammonia engine 2 for a certain period of time. Therefore, the reformed gas is supplied to the combustor 28 from the inside of the cylinder 7 together with the starting gas. Therefore, in the combustor 28, hydrogen in the reforming gas is burned together with the main ammonia gas in the starting gas, so that the main ammonia gas in the starting gas is easily burned. As a result, the start-up time of the reformer 17 is further shortened.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the injector 5 is controlled to be closed once when the temperature of the reformer 17 becomes the specified temperature T1 or higher, but the present invention is not particularly limited to such an embodiment. For example, as shown in FIG. 9, in the combustor 28, the main ammonia gas and the reforming ammonia gas in the starting gas ignite and burn, so that the temperature of the reformer 17 starts to rise and then the injector. 5 may be controlled to be closed once (see FIG. 9B). In this case, once the injector 5 is closed, the reforming ammonia gas is supplied to the combustor 28 through the ammonia engine 2, so that only the reforming ammonia gas burns in the combustor 28.

Further, in the above embodiment, the starting valve 37 is controlled to close when the temperature of the reformer 17 reaches the specified temperature T1, but the present invention is not particularly limited to that mode, and the reformer 17 is not limited to this. If the temperature of the reformer 17 has reached the combustible temperature after the temperature starts to rise, the injector 5 may be controlled to be closed once and the starting valve 37 may be controlled to be closed (Fig.). 9 (e)).

Further, in the above embodiment, when the starter 41 is rotationally driven, the injector 5 and the throttle valve 6 are controlled to open, and the ammonia valve 19 and the air valve 21 are controlled to open. It is not limited to such a form. For example, as shown in FIG. 10, control is performed so that the ammonia valve 19 and the air valve 21 are opened by the time the main ammonia gas supplied to the combustion chamber 7a of the ammonia engine 2 by the injector 5 starts to burn in the combustor 28. (See FIGS. 10 (g) and 10 (h)). In this case, the second control unit 46 of the main controller 44 executes ammonia so that the reforming ammonia gas and the reforming air are supplied to the reformer 17 after the control process by the first control unit 45 is executed. It controls the valve 19 and the air valve 21.

Further, in the present embodiment, the starting valve 37, which is an on-off valve, is arranged in the starting gas flow path 36 connecting the EGR passage 38 and the combustor 28, but the present invention is not particularly limited to that form, for example. A three-way valve may be arranged in the exhaust passage 4, and the three-way valve and the combustor 28 may be connected by a starting gas flow path 36.

Further, in the above embodiment, in the combustor 28, the starting gas introduction unit 31 has an inner peripheral surface of the housing 30 so that a tubular flow of starting gas including ammonia gas and air is generated inside the housing 30. Although it is introduced in the tangential direction of 30a, it is not particularly limited to such a form. The starting gas introduction unit 31 may, for example, introduce the starting gas into the housing 30 in the radial direction of the housing 30. That is, the combustor 28 does not have to be a tubular flame burner as long as it generates the combustion gas supplied to the reformer 17.

Further, in the above embodiment, various valves and the like are controlled based on the temperature of the reformer 17 detected by the temperature sensor 42, but it is not necessary to use the temperature sensor 42 in particular, for example, the flow rate of ammonia gas. , The temperature of the reformer 17 may be estimated from the flow rate of air, time, room temperature and the like. Further, instead of the temperature of the reformer 17, the hydrogen concentration in the reforming gas generated by the reformer 17 may be detected, and various valves and the like may be controlled based on the hydrogen concentration in the reforming gas. ..

Further, in the above embodiment, the reformer 17 has a reforming catalyst 17a having a function of burning ammonia and a function of decomposing ammonia into hydrogen, but the reformer 17 is not particularly limited to that form. The reformer 17 may separately have a combustion catalyst for burning ammonia and a reforming catalyst for decomposing ammonia into hydrogen.

Further, in the above embodiment, a plurality of injectors 5 are provided for each combustion chamber 7a of the ammonia engine 2, but the number of injectors 5 may be one. In this case, the injector 5 may be arranged so as to inject the main ammonia gas into the intake passage 3.

Further, in the above embodiment, the ammonia valve 19 is a flow rate control valve arranged in the ammonia flow path 18, but the configuration of the ammonia valve 19 is not particularly limited to that form, for example, the combustion gas flow path 29. It may be an injector that injects ammonia gas for reforming.

Further, in the above embodiment, the air valve 21 which is a flow rate control valve is arranged in the air flow path 20, but the form is not particularly limited, and for example, a mass flow controller, a compressor, a pump, or the like is used to modify the air flow path 20. Air for reforming may be supplied to the pledger 17.

Further, in the above embodiment, ammonia gas is used as the fuel gas, but the present invention can also be applied to an engine system using a hydrocarbon gas or the like as the fuel gas.

1 ... engine system, 2 ... ammonia engine (engine), 3 ... intake passage, 4 ... exhaust passage, 5 ... injector (fuel injection valve), 6 ... throttle valve (flow control valve), 7 ... cylinder, 8 ... piston, 17 ... Reformer, 26 ... Fuel supply section, 27 ... Air supply section, 28 ... Combustor, 30 ... Housing, 31 ... Starting gas introduction section, 32 ... Ignition section, 36 ... Starting gas flow path, 37 ... Starting valve, 38 ... EGR passage, 39 ... EGR valve (starting gas adjusting unit), 41 ... Starter, 42 ... Temperature sensor (temperature detecting unit), 45 ... First control unit, 46 ... Second control unit, 47 ... 3rd control unit, 48 ... 4th control unit, T1 ... specified temperature (reformable temperature, 1st specified temperature), T2 ... specified temperature (2nd specified temperature), T3 ... specified temperature (1st specified temperature) ).

Claims (6)

An engine with pistons reciprocating in the cylinder,
An intake passage through which air supplied into the cylinder flows, and
The exhaust passage through which the exhaust gas generated in the cylinder flows, and
A fuel injection valve that injects fuel gas into the cylinder,
A flow rate control valve arranged in the intake passage and controlling the flow rate of the air supplied into the cylinder,
A starter that reciprocates the piston and
A reformer that produces a reformed gas containing hydrogen by reforming the fuel gas using the heat generated by burning the fuel gas.
A fuel supply unit that supplies the fuel gas to the reformer,
An air supply unit that supplies the air to the reformer,
A reformed gas flow path through which the reformed gas generated by the reformer flows into the cylinder, and
A combustor that generates combustion gas supplied to the reformer, and
A start-up gas flow path that connects the exhaust passage and the combustor and allows the start-up gas in which the fuel gas and the air are mixed to flow toward the combustor in the cylinder.
A starting gas adjusting unit that adjusts the flow of the starting gas in the starting gas flow path,
The starter, the fuel injection valve, and the flow rate control valve are controlled so that the fuel gas and the air are introduced into the cylinder and the starting gas is discharged from the cylinder when the engine is started. A first control unit that controls the starting gas adjusting unit so that the starting gas is supplied to the combustor, and controls the combustor so that the fuel gas in the starting gas ignites.
The fuel supply unit and the above so that the fuel gas and the air are supplied to the reformer at the same time as the execution of the control process by the first control unit or after the control process by the first control unit is executed. The second control unit that controls the air supply unit and
A third control unit that controls the starting gas adjusting unit so that the supply of the starting gas to the combustor is stopped after the control processing by the first control unit and the second control unit is executed. Engine system with. An EGR passage that connects the exhaust passage and the intake passage and allows a part of the exhaust gas to flow toward the intake passage as EGR gas.
Further provided with an EGR valve for controlling the flow rate of the EGR gas flowing through the EGR passage.
The starting gas flow path connects the exhaust passage and the combustor via the EGR passage by connecting the upstream side of the EGR valve to the combustor in the EGR passage.
The starting gas adjusting unit is a valve that opens and closes the starting gas flow path.
The first control unit controls to open the valve,
The engine system according to claim 1, wherein the third control unit controls to close the valve. Further provided with a temperature detection unit for detecting the temperature of the reformer,
When the temperature of the reformer detected by the temperature detection unit is equal to or higher than a predetermined first predetermined temperature, the third control unit stops supplying the starting gas to the combustor. The engine system according to claim 1 or 2, wherein the starting gas adjusting unit is controlled as described above. The engine system according to claim 3, wherein the first specified temperature is a temperature higher than the reformable temperature at which the reformer can reform the fuel gas. Based on the temperature of the reformer detected by the temperature detection unit, it is determined whether or not the fuel gas in the starting gas has ignited, and when the fuel gas in the starting gas ignites, the cylinder. The fuel injection valve is controlled so that the introduction of the fuel gas into the fuel gas is stopped, and then the temperature of the reformer detected by the temperature detection unit is equal to or higher than the second specified temperature higher than the first specified temperature. 4. The engine system according to claim 4, further comprising a fourth control unit that controls the fuel injection valve so that the fuel gas is reintroduced into the cylinder. The combustor has a circular tubular housing, a starting gas introduction portion that introduces the starting gas so as to generate a tubular flow inside the housing, and a starting gas attached to the housing. It has an ignition unit that ignites the fuel gas in the starting gas introduced into the housing from the introduction unit.
The engine system according to any one of claims 1 to 5, wherein the first control unit controls the ignition unit to ignite.

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