Control device for internal combustion engine

Abstract

To prevent gaseous fuel from reaching an exhaust passage after an internal combustion engine is stopped.SOLUTION: An internal combustion engine 100 comprises: a plurality of cylinders 11; injectors 50 each provided in each of the cylinders 11, which injects gaseous fuel; a fuel tank 71 that stores the gaseous fuel; a fuel supply passage 75 that connects the fuel tank 71 and each of the injectors 50; and a fuel supply valve 76 that opens and closes the fuel supply passage 75. When stopping operation of the internal combustion engine 100, a control device 110 executes: first processing of closing the fuel supply valve 76; and second processing of, when a cylinder 11 with a closed exhaust valve 16 among the plurality of cylinders 11 is designated as a valve closed cylinder, opening each injection port of injector 50 corresponding to one or more cylinders 11 of the valve closed cylinders, while closing each injection port of injector 50 corresponding to the cylinder 11 with an open exhaust valve 16.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control device for an internal combustion engine. [Background technology]

[0002] The internal combustion engine disclosed in Patent Document 1 includes a cylinder, an injector, a fuel tank, a fuel supply passage, and a valve. The fuel tank stores gaseous fuel. The fuel supply passage connects the fuel tank and the injector. The valve is located midway through the fuel supply passage. The valve opens and closes the fuel supply passage. When the internal combustion engine is in operation, the valve is in an open state. In this case, the gaseous fuel in the fuel tank is supplied to the injector via the fuel supply passage. Then, the injector injects the gaseous fuel into the cylinder. On the other hand, when the operation of the internal combustion engine is stopped, the valve is in a closed state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-166424 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a technology such as that disclosed in Patent Document 1 in which gaseous fuel is supplied to an injector through a fuel supply passage, when a valve is closed as the internal combustion engine is stopped, the fuel supply passage between the valve and the injector becomes highly pressurized with gaseous fuel remaining in the fuel supply passage. In addition, gaseous fuel is more likely to leak from the injector nozzle into the cylinder than liquid fuel. If the gaseous fuel leaked into the cylinder reaches the high-temperature exhaust passage immediately after the internal combustion engine is stopped, there is a risk that the gaseous fuel will ignite in the exhaust passage. [Means for solving the problem]

[0005] A control device for an internal combustion engine for solving the above problems includes an engine body into which a plurality of cylinders are defined, an intake passage connected to each of the cylinders, an exhaust passage connected to each of the cylinders, an intake valve provided for each of the cylinders for opening and closing a connection port to the cylinder in the intake passage, an exhaust valve provided for each of the cylinders for opening and closing a connection port to the cylinder in the exhaust passage, an injector provided for each of the cylinders for injecting gaseous fuel to be supplied into the cylinder, a fuel tank that stores the gaseous fuel, and a fuel supply system that connects the fuel tank and the injector for each of the cylinders. This method is applied to an internal combustion engine including a supply passage and a fuel supply valve that is provided in the fuel supply passage closer to the fuel tank than the branch point to the injector for each cylinder, and that opens and closes the fuel supply passage. When the operation of the internal combustion engine is stopped, a first process is executed to close the fuel supply valve, and when a cylinder among the plurality of cylinders whose exhaust valves are closed is determined as a closed cylinder, a second process is executed to open the injection port of the injector corresponding to one or more of the closed cylinders while closing the injection port of the injector corresponding to the cylinder whose exhaust valve is open. Effect of the Invention

[0006] The above technical concept makes it possible to prevent gaseous fuel from reaching the exhaust passage after the internal combustion engine has stopped operating. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing a general configuration of an internal combustion engine. [Diagram 2] FIG. 2 is a schematic diagram showing a schematic configuration of an internal combustion engine. [Diagram 3] FIG. 3 is a schematic diagram showing the configuration of the injector. [Figure 4] FIG. 4 is a flowchart showing the procedure of the purge process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of a control device for an internal combustion engine will be described with reference to the drawings. <Overall configuration of an internal combustion engine> The vehicle 500 is equipped with an internal combustion engine 100. The internal combustion engine 100 is a drive source of the vehicle 500.

[0009] 1 and 2, an internal combustion engine 100 includes an engine body 10, a plurality of cylinders 11, a plurality of pistons 12, a plurality of connecting rods 13, and a crankshaft 14. Note that FIG. 1 shows only one of the plurality of cylinders 11. The same applies to the pistons 12 and the connecting rods 13. In this embodiment, there are four cylinders 11: a first cylinder #1, a second cylinder #2, a third cylinder #3, and a fourth cylinder #4.

[0010] The cylinders 11 are spaces partitioned in the engine body 10. A mixture of intake air and gaseous fuel is burned in the cylinders 11. A piston 12 is provided for each cylinder 11. The piston 12 is located in the cylinder 11. The piston 12 reciprocates in the cylinder 11. The piston 12 is connected to a crankshaft 14 via a connecting rod 13. The crankshaft 14 rotates in response to the movement of the piston 12. The crankshaft 14 is connected to driving wheels 502 via an automatic transmission 501 or the like. The internal combustion engine 100 is a four-stroke, one-cycle engine in which the intake stroke, compression stroke, expansion stroke, and exhaust stroke in each cylinder 11 are completed by the crankshaft 14 rotating 720 degrees.

[0011] As shown in FIG. 1 and FIG. 2, the internal combustion engine 100 includes a plurality of spark plugs 19. Note that FIG. 1 shows only one of the plurality of spark plugs 19. The spark plug 19 is provided for each cylinder 11. The tip of the spark plug 19 is located inside the cylinder 11. The spark plug 19 ignites the mixture in the cylinder 11. In this embodiment, the four spark plugs 19 ignite in the order of the first cylinder #1, the third cylinder #3, the fourth cylinder #4, and the second cylinder #2. In other words, the four cylinders 11 undergo an expansion stroke accompanied by the combustion of the mixture in the order of the first cylinder #1, the third cylinder #3, the fourth cylinder #4, and the second cylinder #2.

[0012] 1 and 2, the internal combustion engine 100 is equipped with a plurality of injectors 50. Note that FIG. 1 shows only one of the plurality of injectors 50. The injector 50 is provided for each cylinder 11. An injection port 54 of the injector 50 is located inside the cylinder 11. That is, the injector 50 injects fuel directly into the cylinder 11 without passing through an intake passage 41 described below. The injector 50 injects hydrogen, which is a gaseous fuel.

[0013] As shown in FIG. 1, the internal combustion engine 100 includes an intake passage 41, an air cleaner 43, a throttle valve 44, and a surge tank 45. The intake passage 41 is a passage for introducing intake air into each cylinder 11. The intake passage 41 is connected to each cylinder 11. The air cleaner 43 is located midway through the intake passage 41. The air cleaner 43 filters the intake air taken into the intake passage 41. The throttle valve 44 is located downstream of the air cleaner 43 in the intake passage 41. The throttle valve 44 adjusts the amount of intake air. The surge tank 45 is located downstream of the throttle valve 44 in the intake passage 41. The surge tank 45 stores a certain volume of intake air.

[0014] The internal combustion engine 100 includes a plurality of intake valves 15 and an intake valve mechanism 25. FIG. 1 shows only one of the plurality of intake valves 15. An intake valve 15 is provided for each cylinder 11. The intake valve 15 is located at a connection port between the intake passage 41 and the cylinder 11. This connection port is also called an opening of the intake passage 41 on the cylinder 11 side. The intake valve mechanism 25 includes an intake camshaft 25A. The intake camshaft 25A rotates in conjunction with the crankshaft 14. The intake camshaft 25A rotates once while the crankshaft 14 rotates twice. The intake valve 15 operates in response to the rotation of the intake camshaft 25A. Due to this operation, the intake valve 15 opens and closes the connection port between the intake passage 41 and the cylinder 11. When the intake valve 15 is open, the intake valve 15 is away from the connection port between the intake passage 41 and the cylinder 11, and the opening degree of the intake valve 15 is greater than 0%. On the other hand, when the intake valve 15 is closed, the intake valve 15 is in contact with the connection port between the intake passage 41 and the cylinder 11, and the opening degree of the intake valve 15 is 0%.

[0015] The internal combustion engine 100 includes an exhaust passage 49 and an oxidation catalyst. The exhaust passage 49 is a passage for discharging exhaust gas from each cylinder 11. The exhaust passage 49 is connected to each cylinder 11. Although not shown, the oxidation catalyst is located midway through the exhaust passage 49. The oxidation catalyst oxidizes components contained in the exhaust gas.

[0016] The internal combustion engine 100 includes a plurality of exhaust valves 16 and an exhaust valve train 26. FIG. 1 shows only one of the plurality of exhaust valves 16. An exhaust valve 16 is provided for each cylinder 11. The exhaust valve 16 is located at a connection port between the exhaust passage 49 and the cylinder 11. This connection port is also called an opening of the exhaust passage 49 on the cylinder 11 side. The exhaust valve train 26 includes an exhaust camshaft 26A. The exhaust camshaft 26A rotates in conjunction with the crankshaft 14. The exhaust camshaft 26A rotates once while the crankshaft 14 rotates twice. The exhaust valve 16 operates in response to the rotation of the exhaust camshaft 26A. Due to this operation, the exhaust valve 16 opens and closes the connection port between the exhaust passage 49 and the cylinder 11. When the exhaust valve 16 is open, the exhaust valve 16 is away from the connection port between the exhaust passage 49 and the cylinder 11, and the opening degree of the exhaust valve 16 is greater than 0%. On the other hand, when the exhaust valve 16 is closed, the exhaust valve 16 is in contact with the connection port between the exhaust passage 49 and the cylinder 11, and the opening degree of the exhaust valve 16 is 0%.

[0017] <Fuel supply system> 2, the internal combustion engine 100 includes a fuel tank 71, a main passage 72, a delivery pipe 73, a plurality of branch passages 74, a fuel supply valve 76, and a pressure regulator 77. The main passage 72, the delivery pipe 73, and the branch passages 74 form a fuel supply passage 75. The branch passage 74 is provided for each injector 50.

[0018] The fuel tank 71 stores hydrogen, which is a gas fuel. The main passage 72 connects the fuel tank 71 and a delivery pipe 73. The delivery pipe 73 is connected to each injector 50 via a branch passage 74 for each injector 50. The pressure regulator 77 is located in the middle of the main passage 72. The pressure regulator 77 adjusts and releases the pressure of the gas fuel. The fuel supply valve 76 is located on the fuel tank 71 side of the pressure regulator 77 in the main passage 72. The fuel supply valve 76 is a valve that opens and closes in response to a command signal from a control device 110, which will be described later. For example, the fuel supply valve 76 is a normally closed solenoid valve. When the fuel supply valve 76 is closed, the fuel supply from the fuel tank 71 to each injector 50 is cut off. When the fuel supply valve 76 is open, the gas fuel is supplied from the fuel tank 71 to each injector 50.

[0019] <Injector> The structure of each injector 50 is identical. The following describes the details of one of the four injectors 50.

[0020] 3, the injector 50 includes a housing 52, a nozzle valve 57, an electromagnetic solenoid 58, a drive circuit 59, and a spring. Note that the spring is not shown in FIG.

[0021] A housing passage 53, which is a passage through which the gas fuel flows, is defined inside the housing 52. The housing passage 53 extends linearly. The tip of the housing passage 53 opens to the outside of the housing 52. This opening serves as an injection port 54 that communicates between the inside and the outside of the housing 52. The portion of the housing passage 53 in front of the injection port 54 serves as a seat surface 55 that is inclined so as to taper toward the injection port 54.

[0022] The nozzle valve 57 is located in the housing passage 53. The nozzle valve 57 is movable toward and away from the seat surface 55. The nozzle valve 57 receives a biasing force from a spring. The nozzle valve 57 is pressed against the seat surface 55 by this biasing force.

[0023] The electromagnetic solenoid 58 drives the operation of the nozzle valve 57. When the electromagnetic solenoid 58 is energized, the nozzle valve 57 moves away from the seat surface 55 against the biasing force of the spring. As a result, the injection port 54 opens. Then, the gaseous fuel is injected from the injection port 54. On the other hand, when the electromagnetic solenoid 58 is de-energized, the nozzle valve 57 is seated on the seat surface 55 by the biasing force of the spring. As a result, the injection port 54 closes. Then, the injection of the gaseous fuel from the injection port 54 stops.

[0024] The drive circuit 59 is interposed between a battery (not shown) mounted on the vehicle 500 and the electromagnetic solenoid 58. The drive circuit 59 is an electric circuit and has a switch and the like. The drive circuit 59 turns on and off the supply of electricity to the electromagnetic solenoid 58 in response to a command signal from a control device 110 (described later).

[0025] <Sensor> 1, the internal combustion engine 100 includes a pressure sensor 91. The pressure sensor 91 detects the internal pressure of the delivery pipe 73. The pressure sensor 91 outputs a signal P corresponding to the detected information.

[0026] The internal combustion engine 100 includes a sensor plate 167 and a crank position sensor 92. The sensor plate 167 rotates integrally with the crankshaft 14. A plurality of teeth 168 are formed on the outer periphery of the sensor plate 167. The plurality of teeth 168 are basically arranged at equal intervals. However, there is one missing tooth portion 169 where the interval between adjacent teeth 168 is larger than the other portions. The crank position sensor 92 is disposed at a position facing the outer periphery of the sensor plate 167. The crank position sensor 92 outputs an L signal when facing the teeth 168 of the sensor plate 167, and outputs an H signal when facing the gap portion between adjacent teeth 168. Therefore, in accordance with the arrangement of the teeth 168 described above, the crank position sensor 92 basically alternately outputs an L signal and an H signal at a constant normal interval. Then, at the portion corresponding to the missing tooth portion 169, the crank position sensor 92 outputs an H signal at an interval longer than the normal interval as a missing tooth signal. Hereinafter, the signals output by the crank position sensor 92 will be collectively referred to as the crank signal CR. Herein, in consideration of the order of the expansion strokes in the cylinders 11 described above, the piston 12 of the first cylinder #1 and the piston 12 of the fourth cylinder #4 are positioned at the top dead center at the same timing. In this embodiment, the position of the missing tooth portion 169 is determined so that the crank signal CR switches from the missing tooth signal to the L signal around the time when the piston 12 of the first cylinder #1 and the piston 12 of the fourth cylinder #4 reach the top dead center.

[0027] The internal combustion engine 100 includes a rotor plate 31 and a cam position sensor 93. The rotor plate 31 rotates integrally with the intake camshaft 25A. Three fan-shaped protrusions 32 are formed on the outer periphery of the rotor plate 31. The three protrusions 32 extend in different occupying ranges in the circumferential direction. The intervals between adjacent protrusions 32 are different from each other. The cam position sensor 93 is disposed at a position facing the outer periphery of the rotor plate 31. The cam position sensor 93 outputs an L signal when facing each protrusion 32, and outputs an H signal when facing a gap portion between adjacent protrusions 32. When a large protrusion, which has the largest occupying range among the three protrusions 32, passes in front of the cam position sensor 93, the cam position sensor 93 outputs an L signal at a longer interval than when the other protrusions 32 pass in front of the cam position sensor 93. Hereinafter, the L signal output by the cam position sensor 93 when the large protrusion passes in front of the cam position sensor 93 is referred to as the longest signal. In the following description, each signal output by the cam position sensor 93 will be collectively referred to as a cam signal M. In this embodiment, the positions of the projections 32 are determined so that the cam signal M switches from the maximum signal to an H signal before and after the piston 12 of the first cylinder #1 reaches the compression top dead center. Since the intake camshaft 25A rotates once while the crankshaft 14 rotates twice, the outer circumferential location of the rotor plate 31 that the cam position sensor 93 faces differs when the piston 12 of the first cylinder #1 is at the compression top dead center from when the piston 12 of the fourth cylinder #4 is at the compression top dead center. Therefore, when the cam signal M switches from the maximum signal to the H signal, the piston 12 of the fourth cylinder #4 is not at the compression top dead center.

[0028] The vehicle 500 is equipped with an ignition switch 99. The ignition switch 99 outputs a signal G in response to an operation by a passenger. <Control device> As shown in FIG. 1, the vehicle 500 includes a control device 110. The control device 110 may be configured as one or more processors that execute various processes according to a computer program (software). The control device 110 may be configured as one or more dedicated hardware circuits, such as an application specific integrated circuit (ASIC), that execute at least a part of the various processes, or a circuit including a combination thereof. The processor includes a CPU 112 and a memory 114, such as a RAM and a ROM. The memory 114 stores program codes or instructions that are configured to cause the CPU 112 to execute processes. The memory 114, i.e., a computer-readable medium, includes any available medium that can be accessed by a general-purpose or dedicated computer. The memory 114 includes an electrically rewritable non-volatile memory.

[0029] The control device 110 repeatedly receives signals from the various sensors in the internal combustion engine 100. The control device 110 grasps the operating state of the internal combustion engine 100 based on the information received from the various sensors. For example, the control device 110 grasps the open / closed states of the intake valve 15 and the exhaust valve 16 based on the crank signal CR and the cam signal M. The control device 110 of this embodiment grasps the open / closed states of the intake valve 15 and the exhaust valve 16 in the following manner, for example. The control device 110 repeatedly calculates the crank angle CA indicating the rotation phase of the crankshaft 14 based on the crank signal CR and the cam signal M. The crank angle CA has a value between 0 degrees and 720 degrees. The control device 110 calculates the crank angle CA from a predetermined reference angle position as a starting point. The reference angle position is, for example, the angle position of the crankshaft 14 when the piston 12 of the first cylinder #1 is at the top dead center of the compression stroke. The crank angle CA is calculated from the reference angle position, so that the crank angle CA reflects the phase of each cylinder 11. The control device 110 can specify the reference angle position by combining the crank signal CR and the cam signal M. For example, when the crank signal CR switches from the missing tooth signal to the L signal and the cam signal M switches from the longest signal to the H signal, the control device 110 can determine that the piston 12 of the first cylinder #1 is at the compression top dead center. Now, in this embodiment, as an example, the opening and closing timings of the intake valve 15 and the exhaust valve 16 during the operation of the internal combustion engine 100 are fixed. That is, the crank angle CA at which the intake valve 15 switches from a closed state to an open state and the crank angle CA at which the intake valve 15 switches from an open state to a closed state are determined in advance for each cylinder 11. Similarly, in this embodiment, the crank angle CA at which the exhaust valve 16 switches from a closed state to an open state, and the crank angle CA at which the exhaust valve 16 switches from an open state to a closed state are determined in advance for each cylinder 11. The control device 110 stores in advance the crank angles CA that are the opening and closing timings of the intake valve 15 and the exhaust valve 16. Therefore, the control device 110 can grasp the opening and closing states of the intake valve 15 and the exhaust valve 16 by referring to the current crank angle CA.

[0030] The control device 110 controls various parts of the internal combustion engine 100. For example, the control device 110 controls the injector 50. Specifically, the control device 110 controls the power supply to the electromagnetic solenoid 58 by outputting a command signal to the drive circuit 59. The control device 110 also controls the opening and closing of the fuel supply valve 76. The control device 110 opens the fuel supply valve 76 while the internal combustion engine 100 is operating. On the other hand, the control device 110 closes the fuel supply valve 76 while the internal combustion engine 100 is stopped.

[0031] The control device 110 receives a signal G from the ignition switch 99. When the control device 110 receives the signal G in response to the ignition switch 99 being turned on, the control device 110 starts the operation of the internal combustion engine 100. During the operation of the internal combustion engine 100, the control device 110 adjusts the opening of the throttle valve 44, injects gaseous fuel from each injector 50, and performs ignition by each spark plug 19. In this way, the control device 110 combusts the air-fuel mixture in each cylinder 11.

[0032] On the other hand, when the control device 110 receives a signal G in response to the ignition switch 99 being turned off, the control device 110 stops the operation of the internal combustion engine 100. At this time, the control device 110 performs the following series of processes. First, the control device 110 stops ignition by each spark plug 19 and fuel injection by each injector 50. As a specific process for stopping fuel injection, the control device 110 closes the injection port 54 of each injector 50 by stopping the supply of electricity to the electromagnetic solenoid 58 of each injector 50. In addition, the control device 110 closes the fuel supply valve 76 in conjunction with stopping the fuel injection. The process in which the control device 110 closes the fuel supply valve 76 is the first process. After this, the control device 110 waits until the rotation of the crankshaft 14 stops. The control device 110 can determine that the rotation of the crankshaft 14 has stopped based on the crank signal CR. The control device 110 starts a purging process, which will be described below, when the rotation of the crankshaft 14 stops. The control device 110 remains in an activated state until the purging process ends.

[0033] As shown in FIG. 4, when the control device 110 starts the purge process, it first executes the process of step S10. In step S10, the control device 110 identifies a target cylinder. The target cylinder is a cylinder 11 among the multiple cylinders 11 in which the exhaust valve 16 is closed and the intake valve 15 is open. The control device 110 grasps the current open / close states of the intake valve 15 and the exhaust valve 16 of each cylinder 11 by referring to the current crank angle CA. Then, the control device 110 identifies the target cylinder. Note that, depending on the settings of the opening / closing timing of the intake valve 15 and the exhaust valve 16, there may be multiple target cylinders corresponding to the current crank angle CA. In this case, the control device 110 identifies all of the multiple target cylinders. After this, the control device 110 advances the process to step S20. If there is no target cylinder that corresponds to the current crank angle CA in step S10, the control device 110 cancels the processes in and after step S20 and ends the purge process.

[0034] In step S20, the control device 110 starts energizing the electromagnetic solenoid 58 of the injector 50 corresponding to the target cylinder identified in step S10. As a result, the control device 110 opens the injection port 54 of the injector 50 of the target cylinder. When the control device 110 identifies multiple target cylinders in step S10, the control device 110 starts energizing the electromagnetic solenoid 58 of the injectors 50 of all of these target cylinders. On the other hand, the control device 110 does not energize the electromagnetic solenoid 58 of all of the injectors 50 other than the target cylinder identified in step S10. In other words, the control device 110 closes the injection port 54 of all of these remaining injectors 50. The remaining injectors 50 include the injector 50 corresponding to the cylinder 11 whose exhaust valve 16 is open and the injector 50 corresponding to the cylinder 11 whose exhaust valve 16 and intake valve 15 are both closed. When the control device 110 starts energizing the electromagnetic solenoid 58 of the injector 50 corresponding to the target cylinder, the process proceeds to step S30. Note that the "injector 50 corresponding to the cylinder 11" refers to the injector 50 that supplies fuel to that cylinder 11.

[0035] In step S30, the control device 110 judges whether the latest value of the internal pressure of the delivery pipe 73 detected by the pressure sensor 91 is equal to or lower than a set value. The control device 110 prestores the set value. The set value is determined in advance, for example, by an experiment or a simulation, as a value at which gas fuel does not leak from the injection port 54 of each injector 50 into the cylinder 11 when the injection port 54 of all the injectors 50 is closed. If the internal pressure of the delivery pipe 73 is higher than the set value (step S30: NO), the control device 110 executes the process of step S30 again. The control device 110 repeats the process of step S30 until the internal pressure of the delivery pipe 73 becomes equal to or lower than the set value. Then, when the internal pressure of the delivery pipe 73 becomes equal to or lower than the set value (step S30: YES), the control device 110 advances the process to step S40.

[0036] In step S40, the control device 110 stops energizing the electromagnetic solenoid 58 that was started to be energized in step S20. As a result, the injection ports 54 of all the injectors 50, including the target cylinder, are closed. After that, the control device 110 ends the series of processes of the purge process.

[0037] In addition, with regard to the above-mentioned purging process, the process in which the control device 110 opens the injection port 54 of the injector 50 of the target cylinder while closing the injection ports 54 of all the remaining injectors 50 is the second process. The control device 110 starts the second process at step S20 and ends the second process at step S40.

[0038] <Operation of the embodiment> It is assumed that the control device 110 receives a signal G in response to the ignition switch 99 being turned off. In response to this, the control device 110 stops fuel injection by the injector 50 in order to stop the internal combustion engine 100. At this time, gaseous fuel may remain in a high-pressure state in a portion of the fuel supply passage 75 between the fuel supply valve 76 and each injector 50, such as the delivery pipe 73. The control device 110 releases this gaseous fuel into the intake passage 41 by a purging process. That is, in the purging process, the control device 110 opens only the injection port 54 of the injector 50 corresponding to the target cylinder. For example, it is assumed that the first cylinder #1 of the four cylinders 11 in FIG. 2 is the target cylinder. In this case, the control device 110 opens only the injection port 54 of the injector 50 corresponding to the first cylinder #1. Then, as shown by arrow L1 in FIG. 2, the gaseous fuel remaining in the fuel supply passage 75 flows only into the first cylinder #1, which is the target cylinder. Here, as shown by dashed line Q in FIG. 1, the exhaust valve 16 in the target cylinder is closed. Therefore, the gaseous fuel that has flowed into the target cylinder does not reach the exhaust passage 49. Meanwhile, in the target cylinder, the intake valve 15 is open. Therefore, as shown by arrow L2 in FIG. 1, the gaseous fuel that has flowed into the target cylinder flows out into the intake passage 41.

[0039] <Effects of the embodiment> (1) As described in the operation of the above embodiment, in the configuration of this embodiment, when the operation of the internal combustion engine 100 is stopped, the gaseous fuel remaining in the fuel supply passage 75 is caused to flow only into the target cylinder. Since the exhaust valve 16 of the target cylinder is closed, the gaseous fuel can be prevented from flowing out into the exhaust passage 49.

[0040] (2) When the operation of the internal combustion engine 100 is stopped, suppose that the injection port 54 of the injector 50 corresponding to the cylinder 11 in which both the intake valve 15 and the exhaust valve 16 are closed is opened. Then, suppose that the gaseous fuel remaining in the fuel supply passage 75 is caused to flow into this cylinder 11. In this case, the gaseous fuel remains in this cylinder 11 at a high concentration until the next time the internal combustion engine 100 is started. If such a high concentration of gaseous fuel remains in the cylinder 11, various problems may occur, such as abnormal combustion occurring in the cylinder 11 when the internal combustion engine 100 is next started.

[0041] In this regard, in the configuration of this embodiment, the gaseous fuel remaining in the fuel supply passage 75 is caused to flow into a target cylinder in which the exhaust valve 16 is closed and the intake valve 15 is open. Since the intake valve 15 of the target cylinder is open, the gaseous fuel that has flowed into the target cylinder flows out into the intake passage 41. Here, the intake passage 41 has a large overall volume because it includes, for example, the surge tank 45, the air cleaner 43, etc. Therefore, the gaseous fuel that has flowed into the intake passage 41 is diffused within the intake passage 41. As a result, the concentration of the gaseous fuel becomes sufficiently low.

[0042] <Example of change> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0043] Regarding the second process, when there are multiple target cylinders, it is not essential to open the nozzles 54 of the injectors 50 of all of these target cylinders. It is sufficient to open the nozzles 54 of the injectors 50 of one or more target cylinders.

[0044] The method of determining the period for which the second process is to continue is not limited to the embodiment in which the internal pressure of the delivery pipe 73 itself is referenced, as in step S30 of the above embodiment. For example, a set time required for the internal pressure of the delivery pipe 73 to drop below a set value is determined in advance by experiment or the like. Then, the second process may be ended when the set time has elapsed after the process of step S20 is ended.

[0045] During operation of the internal combustion engine 100, the opening and closing timing of the intake valve 15 may be changed by changing the relative rotational phase of the intake camshaft 25A with respect to the crankshaft 14. In this case, the amount of change in the relative rotational phase is grasped, and the opening and closing state of the intake valve 15 can be determined by adding the amount of change to the base opening and closing timing. The same applies to the exhaust valve 16.

[0046] A cylinder 11 with its exhaust valve 16 closed is referred to as a closed cylinder. The purge process may be configured to open the nozzle 54 of the injector 50 corresponding to one or more closed cylinders, and close the nozzle 54 of the injector 50 corresponding to the cylinder 11 with its exhaust valve 16 open. The closed cylinder for which the nozzle 54 of the injector 50 is opened is not limited to the target cylinder, and may be a cylinder 11 with its intake valve 15 closed. Even if the nozzle 54 of the injector 50 of a closed cylinder with its intake valve 15 closed is opened, the above effect (1) can be enjoyed because the exhaust valve 16 of this closed cylinder is closed.

[0047] The method for identifying the target cylinder and the closed cylinder is not limited to the above embodiment that uses the crank angle CA. As long as the target cylinder and the closed cylinder can be identified, any method can be used to identify these cylinders.

[0048] The period from when the ignition switch 99 is turned on to when it is turned off is called one trip. During this one trip, when the vehicle 500 is temporarily stopped, the control device 110 may automatically stop and automatically restart the internal combustion engine 100. When such an automatic stop is performed, a purge process may be executed.

[0049] · Gaseous fuels are not limited to hydrogen. The overall configuration of the internal combustion engine 100 is not limited to the example of the above embodiment. For example, the number of cylinders 11 may be changed from that of the above embodiment. The injector 50 may be changed to a type that supplies gaseous fuel into the cylinders 11 via the intake passage 41. It is sufficient that the injector 50 is capable of injecting gaseous fuel to be supplied into the cylinders 11. [Explanation of symbols]

[0050] 10. Main body of the engine 11…Cylinder 15…Intake valve 16...Exhaust valve 41…Intake passage 49…Exhaust passage 50…Injector 71…Fuel tank 75…Fuel supply passage 76…Fuel supply valve 100…Internal combustion engine 110...Control device

Claims

1. the present invention is applied to an internal combustion engine including an engine body having a plurality of cylinders, an intake passage connected to each of the cylinders, an exhaust passage connected to each of the cylinders, an intake valve provided for each of the cylinders and opening and closing a connection port of the intake passage with the cylinder, an exhaust valve provided for each of the cylinders and opening and closing a connection port of the exhaust passage with the cylinder, an injector provided for each of the cylinders and injecting gaseous fuel to be supplied into the cylinder, a fuel tank that stores gaseous fuel, a fuel supply passage connecting the fuel tank and the injectors for each of the cylinders, and a fuel supply valve provided in the fuel supply passage on the fuel tank side relative to a branch point to the injector for each of the cylinders and opening and closing the fuel supply passage, When the operation of the internal combustion engine is stopped, a first process of closing the fuel supply valve; When the cylinder in which the exhaust valve is closed is defined as a closed cylinder among the plurality of cylinders, a second process of opening an injection port of the injector corresponding to one or more of the closed cylinders while closing an injection port of the injector corresponding to the cylinder whose exhaust valve is open; Run A control device for an internal combustion engine.

2. When the cylinder in which the exhaust valve is closed and the intake valve is open is set as a target cylinder among the plurality of cylinders, In the second process, the injection ports of the injectors corresponding to one or more of the target cylinders are opened, while the injection ports of all the remaining injectors are closed. The control device for an internal combustion engine according to claim 1.

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