internal combustion engine

Abstract

To apply gas fuel containing hydrogen and suppress damage caused by occurrence of misfire in one combustion cycle.SOLUTION: An internal combustion engine includes: a combustion chamber to which gas fuel containing hydrogen is supplied; an ignition device configured to ignite the gas fuel in the combustion chamber; and a control device that controls execution of an ignition operation at predetermined ignition timing of the ignition device. The predetermined ignition timing includes: initial ignition timing at which the ignition operation is performed for the first time in one combustion cycle; and subsequent ignition timing at which the ignition operation is performed subsequent to the initial ignition timing in one combustion cycle.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to internal combustion engines. [Background technology]

[0002] In an internal combustion engine such as a gas engine, if a phenomenon occurs in which gas fuel in a combustion chamber does not burn (so-called misfire), the unburned gas fuel is discharged from the combustion chamber and there is a risk that this unburned gas fuel may flow through the exhaust system. Patent Document 1 discloses a misfire detection device that determines misfire in an internal combustion engine from variations in in-cylinder pressure over multiple combustion cycles. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-031766 Summary of the Invention [Problem to be solved by the invention]

[0004] Hydrogen has a higher combustion speed than components contained in conventional gas fuels (e.g., methane contained in city gas and propane contained in LPG). Therefore, when hydrogen is contained in gas fuel, even unburned gas fuel discharged from the combustion chamber due to a misfire during one combustion cycle can ignite in the exhaust system. If unburned gas fuel ignites in the exhaust system, a sudden increase in pressure can damage the exhaust system, or a flame can flow back into the intake system during the overlap period between the exhaust stroke and the intake stroke, causing damage to the intake system.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide an internal combustion engine that uses a gas fuel containing hydrogen and that is capable of suppressing damage caused by the occurrence of misfires in one combustion cycle. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the internal combustion engine of the present disclosure comprises a combustion chamber to which gas fuel containing hydrogen is supplied, an ignition device configured to ignite the gas fuel in the combustion chamber, and a control device that controls the execution of an ignition operation of the ignition device at a predetermined ignition timing, wherein the predetermined ignition timing includes an initial ignition timing at which an ignition operation is performed for the first time in one combustion cycle, and a later ignition timing at which an ignition operation is performed after the initial ignition timing in the one combustion cycle. [Effects of the Invention]

[0007] According to the internal combustion engine of the present disclosure, a gas fuel containing hydrogen is employed, making it possible to suppress damage caused by the occurrence of misfires in one combustion cycle. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram schematically showing the configuration of an internal combustion engine according to a first embodiment. [Figure 2] FIG. 3 is a diagram for explaining predetermined ignition timing of the ignition device according to the first embodiment. [Figure 3] FIG. 4 is a diagram schematically showing the configuration of an internal combustion engine according to a second embodiment. [Figure 4] 4 is a graph showing the relationship between pressure and crank angle. [Figure 5] FIG. 10 is a diagram schematically showing the configuration of an internal combustion engine according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an internal combustion engine according to an embodiment of the present disclosure will be described with reference to the drawings. The embodiment shows one aspect of the present disclosure, and does not limit the present disclosure. The embodiment can be arbitrarily modified within the scope of the technical concept of the present disclosure.

[0010] First Embodiment (composition) Fig. 1 is a diagram schematically illustrating the configuration of an internal combustion engine 1 according to a first embodiment. As illustrated in Fig. 1, the internal combustion engine 1 includes a combustion chamber 2 to which gas fuel F containing hydrogen is supplied, an ignition device 4 configured to ignite the gas fuel F in the combustion chamber 2, and a control device 6 that controls the execution of an ignition operation of the ignition device 4 at a predetermined ignition timing.

[0011] In this disclosure, "hydrogen-containing gas fuel F" includes those containing hydrogen and fuels other than hydrogen (mixed combustion) and those containing only hydrogen (monocarbon combustion). Furthermore, even those containing hydrogen and fuels other than hydrogen can be classified as fuels where hydrogen is the main component (volume ratio of hydrogen is 50% or more) and fuels where a fuel other than hydrogen is the main component (volume ratio of hydrogen is less than 50%). "Hydrogen-containing gas fuel F" includes all of these cases.

[0012] The combustion chamber 2 includes a cylindrical cylinder 8 and a piston 10 disposed inside the cylinder 8. The combustion chamber 2 is configured so that gas fuel F is supplied to a main chamber 12 defined by the inner surface of the cylinder 8 and the upper surface of the piston 10. The piston 10 is connected to a crankshaft 14 via a connecting rod 13, so that the reciprocating motion of the piston 10 is converted into rotation. The crankshaft 14 rotates twice during one combustion cycle C, which will be described later.

[0013] In the first embodiment, as illustrated in FIG. 1, the internal combustion engine 1 includes an intake passage 16 for sending air A to the combustion chamber 2, a compressor 18 for compressing the air A flowing through the intake passage 16, an exhaust passage 22 for discharging exhaust G discharged from the combustion chamber 2 to the outside of the internal combustion engine 1, and a turbine 24 that is rotationally driven by the exhaust G flowing through the exhaust passage 22.

[0014] One end of the intake passage 16 is open to the atmosphere, and the other end is open to the main chamber 12. Air A that flows in from one end of the intake passage 16 flows through the intake passage 16 toward the main chamber 12. That is, the intake passage 16 has an inlet at one end through which the air A flows in, and an outlet at the other end through which the air A flows out. Hereinafter, the outlet of the intake passage 16 will be referred to as an intake port 19. An intake valve 17 that opens and closes the intake port 19 is provided in the intake passage 16.

[0015] One end of the exhaust flow path 22 is open to the main chamber 12, and the other end is open to the atmosphere. Exhaust gas G that flows in from one end of the exhaust flow path 22 flows through the exhaust flow path 22 toward the other end (atmosphere) of the exhaust flow path 22. That is, the exhaust flow path 22 has an inlet at one end through which the exhaust gas G flows in, and an outlet at the other end through which the exhaust gas G flows out. Hereinafter, the inlet of the exhaust flow path 22 will be referred to as an exhaust port 25. The exhaust flow path 22 is provided with an exhaust valve 23 that opens and closes the exhaust port 25.

[0016] 1, the compressor 18 is provided in the intake passage 16, and the turbine 24 is provided in the exhaust passage 22. The compressor 18 and the turbine 24 are configured coaxially, and the compressor 18 compresses the air A flowing through the intake passage 16 as the turbine 24 rotates.

[0017] In the embodiment illustrated in FIG. 1, the internal combustion engine 1 includes a gaseous fuel supply device 20 that is provided in the intake passage 16 and supplies gaseous fuel F to the intake passage 16. The gaseous fuel supply device 20 is located closer to the combustion chamber 2 than the compressor 18 in the intake passage 16. In other words, the gaseous fuel supply device 20 mixes the gaseous fuel F with the air A compressed by the compressor 18. In this manner, the internal combustion engine 1 according to the first embodiment employs premixed combustion, which burns an air-fuel mixture obtained by mixing air A and gaseous fuel F. Note that in some embodiments, the internal combustion engine 1 is configured to combust an air-fuel mixture obtained by mixing uncompressed air A (air at atmospheric pressure) and gaseous fuel F.

[0018] 1, the gaseous fuel supply device 20 is located closer to the compressor 18 than the intake valve 17 in the intake passage 16. Although not shown, in some embodiments, the internal combustion engine 1 includes an air cooler that is provided on the combustion chamber 2 side of the intake passage 16 closer to the compressor 18 and that cools the air A compressed by the compressor 18. In this case, the gaseous fuel supply device 20 is located on the combustion chamber 2 side of the intake passage 16 closer to the air cooler.

[0019] The ignition device 4 includes an ignition plug 21 disposed in the main chamber 12, and by generating a spark discharge from the ignition plug 21, the gas fuel F (air-fuel mixture) in the main chamber 12 is ignited and burned, generating a flame.

[0020] The control device 6 is a computer such as an electronic control device, and includes a processor such as a CPU or GPU (not shown), memories such as a ROM or RAM, an I / O interface, etc. The control device 6 realizes each functional unit provided in the control device 6 by the processor operating (calculating, etc.) according to the instructions of a program loaded into the memory.

[0021] 1, the control device 6 includes an ignition unit 50 electrically connected to the ignition device 4. The ignition unit 50 transmits an ignition signal S1 to the ignition device 4. Upon receiving the ignition signal S1, the ignition device 4 generates a spark discharge from the spark plug 21, thereby igniting and burning the gas fuel F in the main chamber 12. In this manner, by transmitting the ignition signal S1, the control device 6 can control the execution of the ignition operation of the ignition device 4 at a predetermined ignition timing.

[0022] In the embodiment illustrated in FIG. 1, the internal combustion engine 1 includes an angle sensor 26 that detects a rotation angle S2 of the crankshaft 14. The control device 6 includes a crank angle detection unit 52 that is electrically connected to the angle sensor 26. The crank angle detection unit 52 acquires the rotation angle S2 from the angle sensor 26 and converts it into a crank angle θ (0 degrees≦θ≦720 degrees). The ignition unit 50 transmits an ignition signal S1 to the ignition device 4 at the timing when the crank angle detection unit 52 acquires a predetermined crank angle θ. The ignition device 4 then performs an ignition operation simultaneously with receiving the ignition signal S1 or immediately after receiving the ignition signal S1.

[0023] The predetermined ignition timing of the ignition device 4 will now be described. Fig. 2 is a diagram for explaining the predetermined ignition timing of the ignition device 4 according to the first embodiment, and shows one combustion cycle C. As illustrated in Fig. 2, one combustion cycle C includes an intake stroke P1, a compression stroke P2, a combustion stroke P3, and an exhaust stroke P4.

[0024] In the embodiment illustrated in Fig. 2, one combustion cycle C begins with the start of the intake stroke P1 and ends with the end of the exhaust stroke P4, and is executed in the order of the intake stroke P1, compression stroke P2, combustion stroke P3, and exhaust stroke P4. Fig. 2 also illustrates the timing at which the piston 10 reaches top dead center (TDC) and bottom dead center (BDC) in one combustion cycle C. In the present disclosure, the crank angle θ when the piston 10 reaches top dead center (TDC) in the intake stroke P1 is defined as 0 degrees. The crank angle θ increases as the engine progresses from the intake stroke P1 to the exhaust stroke P4, and the crank angle θ when the piston 10 reaches top dead center (TDC) in the exhaust stroke P4 is defined as 720 degrees.

[0025] During the intake stroke P1, gas fuel F (air-fuel mixture) is drawn into the main combustion chamber 12. In the embodiment illustrated in FIG. 2, the intake stroke P1 starts at timing t1 when the intake port 19 opens and ends at timing t2 when the intake port 19 closes. The piston 10 moves from top dead center (TDC) toward bottom dead center (BDC) during the intake stroke P1, thereby drawing the air-fuel mixture into the main combustion chamber 12. During the intake stroke P1, the exhaust port 25 is closed; however, the exhaust port 25 may be closed at the same time as the intake port 19 opens, or may be closed after the intake port 19 opens.

[0026] In the compression stroke P2, the air-fuel mixture in the main combustion chamber 12 is compressed. In the embodiment illustrated in Fig. 2, the compression stroke P2 starts at the timing t2 described above and ends at timing t3 when the piston 10 reaches top dead center (compression top dead center). As the piston 10 moves from bottom dead center (BDC) toward top dead center (BDC), the air-fuel mixture in the main combustion chamber 12 is compressed.

[0027] In the combustion stroke P3, the air-fuel mixture compressed in the compression stroke P2 is burned. In the embodiment illustrated in FIG. 2, the combustion stroke P3 begins at the timing t3 described above. This timing t3 is the initial ignition timing t3 at which the ignition device 4 performs an ignition operation for the first time in one combustion cycle C. That is, in one combustion cycle C, the ignition unit 50 of the control device 6 transmits the ignition signal S1 to the ignition device 4 for the first time when the crank angle detection unit 52 acquires a crank angle θ of 360 degrees. In the combustion stroke P3, the compressed air-fuel mixture is ignited by a spark from the spark plug 21, and the combustion (expansion) of the mixture pushes the piston 10 down toward bottom dead center (BDC). The combustion stroke P3 ends at timing t4 when the exhaust port 25 opens. The exhaust port 25 opens before the piston 10 reaches bottom dead center. That is, timing t4 occurs before the piston 10 reaches bottom dead center.

[0028] In the exhaust stroke P4, the product gas generated by the combustion of the air-fuel mixture is discharged from the main combustion chamber 12 as exhaust gas G. In the embodiment illustrated in FIG. 2, the exhaust stroke P4 starts at the timing t4 described above and ends at timing t5 when the exhaust port 25 closes. As the piston 10 moves from bottom dead center (BDC) toward top dead center (BDC), the product gas in the main combustion chamber 12 is discharged to the outside of the main combustion chamber 12 as exhaust gas G. In the first embodiment, as illustrated in FIG. 2, part of the exhaust stroke P4 and part of the intake stroke P11 in the combustion cycle following one combustion cycle C overlap each other.

[0029] The predetermined ignition timing of the ignition device 4 includes the above-mentioned initial ignition timing t3 as well as the later ignition timing ta. The later ignition timing ta is later than the initial ignition timing t3 in one combustion cycle C. In the first embodiment, as illustrated in FIG. 2, the later ignition timing ta includes a first later ignition timing ta1(ta) and a second later ignition timing ta2(ta).

[0030] The first later ignition timing ta1 is included in the combustion stroke P3 of one combustion cycle C. In the first embodiment, the first later ignition timing ta1 is included in a first range R1 from 15° ATDC to 25° ATDC. In other words, the first later ignition timing ta1 is included in a period in one combustion cycle C in which the crankshaft 14 rotates from 15° to 25° (crank angle θ is 375° to 385°) after the piston 10 reaches the second top dead center (compression top dead center). The ignition unit 50 of the control device 6 transmits an ignition signal S1 to the ignition device 4 at the timing (first later ignition timing ta1) when the crank angle detection unit 52 acquires a crank angle θ of, for example, 380°. The ignition device 4 then performs an ignition operation at the first later ignition timing ta1. In the following description, it is assumed that the timing when the crank angle θ is 380° is the same as the first later ignition timing ta1.

[0031] The second later ignition timing ta2 is included in the exhaust stroke P4 of one combustion cycle C. In the first embodiment, as illustrated in FIG. 2, the second later ignition timing ta2 is immediately after the start of the exhaust stroke P4, and is included, for example, in the period from timing t4 until the piston 10 reaches the second bottom dead center (crank angle θ is 540 degrees) in one combustion cycle C. The ignition unit 50 of the control device 6 transmits the ignition signal S1 to the ignition device 4 at the timing (second later ignition timing ta2) when the crank angle detection unit 52 acquires a crank angle θ of, for example, 535 degrees. Then, the ignition device 4 performs an ignition operation at the second later ignition timing ta2. In the following description, the timing when the crank angle θ is 535 degrees will be assumed to be the same timing as the second later ignition timing ta2.

[0032] (Actions and Effects) The operation and effect of the internal combustion engine 1 according to the first embodiment will be described. Hydrogen has a higher combustion speed than components contained in conventional gas fuels (for example, methane contained in city gas or propane contained in LPG). Therefore, even unburned gas fuel F discharged from the main combustion chamber 12 due to a misfire in one combustion cycle C may ignite in the exhaust passage 22 upon contact with exhaust gas G discharged from the combustion cycle following this one combustion cycle C. If ignition occurs, a sudden increase in pressure may damage the exhaust passage 22 and the turbine 24. Furthermore, flames may flow back into the intake passage 16 during the overlap period when part of the exhaust stroke P4 and part of the intake stroke P11 overlap, potentially damaging the intake passage 16.

[0033] In contrast, according to the first embodiment, the ignition device 4 performs ignition operations at the first and second later ignition timings ta1 and ta2, which are after the initial ignition timing t3, in one combustion cycle C, regardless of whether a misfire occurs. Therefore, the air-fuel mixture (hydrogen) in the main combustion chamber 12 is combusted regardless of whether a misfire occurs in one combustion cycle C, and therefore damage to the intake passage 16 and the exhaust passage 22 due to a misfire (ignition of hydrogen) in one combustion cycle C can be suppressed.

[0034] According to the first embodiment, the ignition device 4 performs the ignition operation at the first subsequent ignition timing ta1, so that the unburned gas fuel F that was not completely burned during the ignition operation at the initial ignition timing t3 is burned in the combustion stroke P3 in the same combustion cycle C, thereby suppressing the amount of unburned gas fuel F discharged from the main chamber 12.

[0035] If the first post-ignition timing ta1 is earlier than 15° ATDC (the crankshaft 14 rotates 15 degrees from the compression top dead center), the pressure Pr in the cylinder 8 is not sufficiently high, making it difficult to determine whether a misfire has occurred. On the other hand, if the first post-ignition timing ta1 is later than 25° ATDC (the crankshaft 14 rotates 25 degrees from the compression top dead center), the time until the timing t4 at which the exhaust port 25 opens is short, which may result in insufficient combustion of the unburned gas fuel F. According to the first embodiment, by setting the first post-ignition timing in the range from 15° ATDC to 25° ATDC, it is possible to easily determine whether a misfire has occurred and suppress the generation of unburned gas fuel F.

[0036] According to the first embodiment, the ignition device 4 performs the ignition operation at the second later ignition timing ta2, so that the unburned gas fuel F that was not completely burned during the ignition operation at the initial ignition timing t3 or the ignition operation at the first later ignition timing is burned during the exhaust stroke P4 in the same combustion cycle C, thereby suppressing the amount of unburned gas fuel F discharged from the main chamber 12.

[0037] In the first embodiment, the later ignition timing ta includes both the first later ignition timing ta1 and the second later ignition timing ta2, but the present disclosure is not limited to this. In some embodiments, the later ignition timing ta includes either the first later ignition timing ta1 or the second later ignition timing ta2.

[0038] In the first embodiment, the later ignition timing ta includes one first later ignition timing ta1 and one second later ignition timing ta2, but the present disclosure is not limited to this. In some embodiments, the later ignition timing ta includes a plurality of first later ignition timings ta1. In some embodiments, the later ignition timing ta includes a plurality of second later ignition timings ta2.

[0039] Second Embodiment An internal combustion engine 1 according to a second embodiment of the present disclosure will be described. The internal combustion engine 1 according to the second embodiment is obtained by adding a misfire detection device 28 to the internal combustion engine 1 according to the first embodiment. In the second embodiment, the same components as those in the first embodiment are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0040] (composition) Fig. 3 is a diagram schematically showing the configuration of an internal combustion engine 1 according to a second embodiment. As illustrated in Fig. 3, the internal combustion engine 1 further includes a misfire detection device 28 that detects misfire in the combustion chamber 2 during one combustion cycle C. The control device 6 is configured to execute an ignition operation at the post-ignition timing ta of the ignition device 4 when the misfire detection device 28 detects misfire in the combustion chamber 2. The control device 6 is also configured to stop the ignition operation at the post-ignition timing ta of the ignition device 4 when the misfire detection device 28 does not detect misfire in the combustion chamber 2.

[0041] In the second embodiment, the control device 6 includes a misfire detection device 28. The control device 6 and the misfire detection device 28 are configured as an integrated unit. In some embodiments, the control device 6 and the misfire detection device 28 are configured as separate entities. The misfire detection device 28 (control device 6) further includes a misfire determination unit 54 that is electrically connected to a pressure sensor 29 that can detect the pressure Pr in the cylinder 8. The misfire determination unit 54 determines whether or not a misfire has occurred in the main combustion chamber 12 based on the pressure Pr obtained from the pressure sensor 29.

[0042] An example of a method for determining misfire by the misfire determination unit 54 will be described below. FIG. 4 is a graph showing the relationship between pressure Pr and crank angle θ. In the graph shown in FIG. 4, the horizontal axis represents crank angle θ, and the vertical axis represents pressure Pr. FIG. 4 shows pressure Pr for each of three combustion cycles. The first combustion cycle C1 is shown by a solid line, the second combustion cycle C2 is shown by a dashed line, and the third combustion cycle C3 is shown by a dotted line.

[0043] 4, the range in which the crank angle θ is equal to or greater than 360 degrees and equal to or less than 375 degrees is defined as the second range R2. In other words, the second range R2 is the period from the second top dead center (compression top dead center) in one combustion cycle C until the crankshaft 14 rotates 15 degrees. In some embodiments, the second range R2 is after the initial ignition timing t3 and before the first subsequent ignition timing ta1 in one combustion cycle C.

[0044] The misfire determination unit 54 determines that a misfire has occurred if the maximum pressure Pmax in the second range R2 is equal to or less than a preset threshold value Pt, and determines that a misfire has not occurred if the maximum pressure Pmax exceeds the threshold value Pt. In the example shown in Figure 4, the misfire determination unit 54 determines that a misfire has not occurred in the first combustion cycle C1 and the second combustion cycle C2, and determines that a misfire has occurred in the third combustion cycle C3.

[0045] In the second embodiment, when the misfire determination unit 54 determines that a misfire has occurred, the ignition unit 50 of the control device 6 sends an ignition signal S1 to the ignition device 4 at both the first and second later ignition timings ta1 and ta2 (the timings when the crank angle θ is 380 degrees and 535 degrees). The ignition device 4 then executes ignition operations at both the first and second later ignition timings ta1 and ta2. In the example illustrated in FIG. 4, in the third combustion cycle C3, the ignition device 4 executes ignition operations at both the first and second later ignition timings ta1 and ta2.

[0046] In the second embodiment, if the misfire determination unit 54 does not determine a misfire, the ignition unit 50 of the control device 6 does not send the ignition signal S1 to the ignition device 4 at both the first later ignition timing ta1 and the second later ignition timing ta2 (the timings when the crank angle θ is 380 degrees and 535 degrees). Therefore, the ignition device 4 does not perform the ignition operation at both the first later ignition timing ta1 and the second later ignition timing ta2. In the example shown in FIG. 4, the ignition operation of the ignition device 4 is stopped at both the first later ignition timing ta1 and the second later ignition timing ta2 in both the first combustion cycle C1 and the second combustion cycle C2.

[0047] (Actions and Effects) The operation and effect of the internal combustion engine 1 according to the second embodiment will be described. According to the second embodiment, the ignition device 4 does not perform the ignition operation at the first later ignition timing ta1 and the second later ignition timing ta2 if the misfire detection device 28 does not detect a misfire in the main combustion chamber 12. This makes it possible to extend the product life of the ignition device 4 compared to when the ignition device 4 performs the ignition operation at the first later ignition timing ta1 and the second later ignition timing ta2 regardless of whether a misfire occurs.

[0048] As described above, hydrogen has a high combustion speed, so it is desirable to suppress the amount of unburned gas fuel F discharged from the main combustion chamber 12 into the exhaust passage 22 even in one combustion cycle C. According to the second embodiment, a misfire determination is performed during one combustion cycle C, and if a misfire is determined, the ignition device 4 performs an ignition operation at each of the first and second later ignition timings ta1 and ta2 in this one combustion cycle. Therefore, the amount of unburned gas fuel F discharged into the exhaust passage 22 in one combustion cycle C can be suppressed.

[0049] In the second embodiment, the misfire detection device 28 detects misfire based on whether the maximum pressure Pmax exceeds the threshold value Pt, but the present disclosure is not limited to this. In some embodiments, the misfire detection device 28 is configured to determine a misfire when the pressure difference between two timings at which the piston 10 is at a common position is equal to or less than a preset threshold value. For example, the misfire detection device is configured to determine a misfire when the difference between the pressure Pr at -20° ATDC and the pressure Pr at 20° ATDC is equal to or less than a threshold value.

[0050] In the second embodiment, the misfire detection device 28 detects misfire based on the pressure Pr inside the cylinder 8, but the present disclosure is not limited to this. The misfire detection device 28 may detect misfire based on a detected value other than the pressure Pr inside the cylinder 8 (for example, engine vibration, the rotation speed or torque of the crankshaft, exhaust gas components, etc.).

[0051] Third Embodiment An internal combustion engine 1 according to a third embodiment of the present disclosure will be described. The internal combustion engine 1 according to the third embodiment is obtained by adding a hydrogen combustion device 30 to the internal combustion engine 1 according to the second embodiment. In the third embodiment, the same components as those in the second embodiment are given the same reference numerals, and detailed description thereof will be omitted. The internal combustion engine 1 according to some embodiments is obtained by adding a hydrogen combustion device 30 to the internal combustion engine 1 according to the first embodiment.

[0052] (composition) Fig. 5 is a diagram schematically illustrating the configuration of an internal combustion engine 1 according to a third embodiment. As illustrated in Fig. 5, the internal combustion engine 1 further includes a hydrogen combustion device 30 that is disposed in the exhaust passage 22 and that combusts hydrogen contained in the gas fuel F.

[0053] In the third embodiment, the hydrogen combustion device 30 is a ceramic body containing ceramic. The hydrogen combustion device 30 is disposed on the side of the exhaust flow path 22 closer to the inlet than to the outlet (the exhaust port 25 side). The hydrogen combustion device 30 is disposed on the combustion chamber 2 side of the turbine 24 in the exhaust flow path 22. More specifically, as illustrated in FIG. 5 , the hydrogen combustion device 30 is disposed in a region X of the exhaust flow path 22 that is reached by the exhaust gas G discharged from the main chamber 12 during the exhaust stroke P4 of one combustion cycle C. In some embodiments, the hydrogen combustion device 30 is disposed in the region X that is reached by the exhaust gas G in the event of a misfire, and is capable of combusting hydrogen contained in the exhaust gas G in the event of a misfire in one combustion cycle C.

[0054] (Actions and Effects) According to the third embodiment, even if unburned gas fuel F is discharged from the main chamber 12 into the exhaust passage 22, the hydrogen contained in this unburned gas fuel F is combusted by the hydrogen combustion device 30. This makes it possible to suppress the accumulation of hydrogen in the exhaust passage 22 and prevent problems caused by the ignition of the accumulated hydrogen.

[0055] If the hydrogen combustion device 30 were located outside the region X of the exhaust flow path 22, it would be unable to combust the hydrogen contained in the unburned gas fuel F discharged from the exhaust stroke P4 in one combustion cycle C, and the concentration of hydrogen remaining in the exhaust flow path 22 would increase, increasing the possibility of ignition. However, according to the third embodiment, the hydrogen combustion device 30 is located within the region X of the exhaust flow path 22, and therefore it is possible to combust the hydrogen contained in the unburned gas fuel F discharged from the exhaust stroke P4 in one combustion cycle C.

[0056] According to the third embodiment, the hydrogen combustion device 30 is a ceramic body. By placing the ceramic body in the exhaust flow path 22, the temperature of the ceramic body is raised by the exhaust gas G discharged from the main combustion chamber 12, making the ceramic body ready for hydrogen combustion. In this way, a hydrogen combustion device 30 with a simple configuration can be provided in the internal combustion engine 1. Note that, although the hydrogen combustion device 30 is a ceramic body in the third embodiment, the present disclosure is not limited to this form. The hydrogen combustion device 30 may also be a glow plug or a burner.

[0057] In the first to third embodiments, the internal combustion engine 1 reduces the amount of unburned gas fuel F discharged into the exhaust passage 22 by controlling the execution of the ignition operation of the ignition device 4 at a predetermined ignition timing using the control device 6, thereby suppressing damage caused by the occurrence of misfires in one combustion cycle, but the present disclosure is not limited to this form.

[0058] In some embodiments, the internal combustion engine 1 includes a combustion chamber 2 to which a gas fuel F containing hydrogen is supplied, an exhaust passage 22 through which exhaust G discharged from the combustion chamber 2 flows, and a hydrogen combustion device 30 disposed in the exhaust passage 22 for combusting hydrogen contained in the gas fuel F. With this configuration, because the hydrogen combustion device 30 is disposed in the exhaust passage 22, even if a misfire occurs and unburned gas fuel F is discharged into the exhaust passage 22, the hydrogen contained in this unburned gas fuel F can be combusted. Therefore, damage due to the occurrence of a misfire in one combustion cycle of the internal combustion engine 1 employing the gas fuel F containing hydrogen can be suppressed.

[0059] The contents described in each of the above embodiments can be understood, for example, as follows.

[0060] [1] The internal combustion engine (1) according to the present disclosure is a combustion chamber (2) to which a gas fuel (F) containing hydrogen is supplied; an ignition device (4) configured to ignite the gaseous fuel in the combustion chamber; a control device (6) that controls the execution of an ignition operation at a predetermined ignition timing of the ignition device, The predetermined ignition timing includes an initial ignition timing (t3) at which an ignition operation is performed for the first time in one combustion cycle (C), and a later ignition timing (ta) at which an ignition operation is performed after the initial ignition timing in the one combustion cycle.

[0061] According to the configuration described in [1] above, gas fuel containing hydrogen is supplied to the combustion chamber. The ignition device then performs ignition even at the post-ignition timing, which is after the initial ignition timing, at which ignition occurs for the first time in one combustion cycle, regardless of whether or not a misfire occurs. Therefore, regardless of whether a misfire occurs in one combustion cycle, the hydrogen contained in the gas fuel in the combustion chamber is burned, thereby suppressing damage caused by the occurrence of a misfire (ignition of hydrogen) in one combustion cycle C.

[0062] [2] In some embodiments, in the configuration described in [1] above, the later ignition timing includes a first later ignition timing (ta1) in which an ignition operation is performed in a combustion stroke (P3) of the one combustion cycle.

[0063] According to the configuration described in [2] above, the unburned gas fuel that was not completely burned during the ignition operation at the initial ignition timing of the ignition device can be burned in the combustion stroke of the same combustion cycle, thereby reducing the amount of unburned gas fuel discharged from the combustion chamber.

[0064] [3] In some embodiments, in the configuration described in [2] above, the first post-ignition timing is within a range (R1) from 15° ATDC to 25° ATDC.

[0065] If the first post-ignition timing is set before 15° ATDC, the pressure in the combustion chamber is not high enough, making it difficult to determine whether a misfire has occurred. On the other hand, if the first post-ignition timing is set after 25° ATDC, the time until the start of the exhaust stroke is short, which may result in insufficient combustion of unburned fuel. According to the configuration described in [3] above, by setting the first post-ignition timing in the range from 15° ATDC to 25° ATDC, it is possible to easily determine whether a misfire has occurred and suppress the generation of unburned fuel.

[0066] [4] In some embodiments, in the configuration described in any one of [1] to [3] above, The later ignition timing includes a second later ignition timing (ta2) at which an ignition operation is performed in the exhaust stroke (P4) of the one combustion cycle.

[0067] According to the configuration described in [4] above, the unburned gas fuel that was not completely burned during the ignition operation at the initial ignition timing of the ignition device is burned during the exhaust stroke of the same combustion cycle, thereby reducing the amount of unburned gas fuel discharged from the combustion chamber.

[0068] [5] In some embodiments, in the configuration described in any one of [1] to [4] above, a misfire detection device (28) that detects misfire in the combustion chamber during one combustion cycle, The control device When the misfire detection device detects a misfire in the combustion chamber, the ignition device is configured to perform an ignition operation at the later ignition timing, When the misfire detection device does not detect a misfire in the combustion chamber, the ignition device is configured to stop an ignition operation at the later ignition timing.

[0069] According to the configuration described in [5] above, the ignition device does not perform the ignition operation at the later ignition timing if the misfire detection device does not detect a misfire in the combustion chamber. Therefore, the product life of the ignition device can be extended compared to when the ignition operation is performed at the later ignition timing regardless of whether a misfire occurs or not.

[0070] [6] In some embodiments, in the configuration described in [5] above, The misfire detection device is configured to determine that a misfire has occurred when the maximum pressure (Pmax) in the combustion chamber after the initial ignition timing and before the post-ignition timing of one combustion cycle is equal to or lower than a predetermined pressure (Pt).

[0071] Because hydrogen has a high combustion speed, it is desirable to suppress the amount of unburned gas fuel discharged from the combustion chamber during one combustion cycle. According to the configuration described in [6] above, misfire detection is performed during one combustion cycle, and if a misfire is detected, ignition is performed at the post-ignition timing of that combustion cycle. This makes it possible to suppress the amount of unburned gas fuel discharged from the combustion chamber during one combustion cycle.

[0072] [7] In some embodiments, in the configuration described in any one of [1] to [6] above, The system further includes a hydrogen combustion device (30) for combusting hydrogen contained in the gas fuel, The hydrogen combustion device is disposed in an exhaust flow path (22) through which exhaust gas discharged from the combustion chamber flows.

[0073] According to the configuration described in [7] above, even if unburned gas fuel is discharged from the combustion chamber into the exhaust passage, the hydrogen contained in this unburned gas fuel is combusted by the hydrogen combustion device, which prevents hydrogen from accumulating in the exhaust passage and prevents problems caused by ignition of the accumulated hydrogen.

[0074] [8] In some embodiments, in the configuration described in [7] above, The hydrogen combustion device is disposed in a region (X) of the exhaust passage where exhaust gas (G) discharged from the combustion chamber in the exhaust stroke of one combustion cycle reaches.

[0075] According to the configuration described in [8] above, it is possible to burn hydrogen contained in unburned gas fuel in one combustion cycle.

[0076] [9] In some embodiments, in the configuration described in [7] or [8] above, The hydrogen combustion device is a ceramic body comprising a ceramic.

[0077] By placing the ceramic body in the exhaust flow path, the temperature of the ceramic body is raised by the exhaust gas discharged from the combustion chamber and flowing through the exhaust flow path, making the ceramic body ready for hydrogen combustion. According to the configuration described in [9] above, a hydrogen combustion device with a simple configuration can be provided.

[0078]

[10] The internal combustion engine according to the present disclosure comprises: a combustion chamber to which a gas fuel containing hydrogen is supplied; an exhaust flow path through which exhaust gas discharged from the combustion chamber flows; and a hydrogen combustion device disposed in the exhaust passage for combusting hydrogen contained in the gas fuel.

[0079] According to the configuration described in

[10] above, since the hydrogen combustion device is disposed in the exhaust passage, even if a misfire occurs and unburned gas fuel is discharged into the exhaust passage, the hydrogen contained in the unburned gas fuel can be burned. Therefore, damage due to a misfire during one combustion cycle of an internal combustion engine that uses a gas fuel containing hydrogen can be suppressed. [Explanation of symbols]

[0080] 1. Internal combustion engine 2. Combustion chamber 4 Ignition device 6. Control device 8 cylinders 10 pistons 12 Main room 13 Connecting rod 14 crankshaft 16 Intake passage 17 Intake valve 18 Compressor 19 Intake port 20 Gas fuel supply device 21 Spark plug 22 Exhaust flow path 23 Exhaust valve 24 Turbine 25 exhaust port 26 Angle Sensor 28 Misfire detection device 29 Pressure Sensor 30 Hydrogen Combustion Device 50 Ignition part 52 Crank angle detector 54 Misfire determination section A. Air C1 combustion cycle F Gas fuel G. Exhaust P1 intake stroke P2 compression stroke P3 Combustion process P4 Exhaust stroke Pr Pressure Pmax Maximum pressure Pt threshold R1 First range R2 Second range S1 ignition signal S2 rotation angle X area t3 First ignition timing ta after ignition timing ta1 1st rear ignition timing ta2 Second rear ignition timing

Claims

1. a combustion chamber to which a gas fuel containing hydrogen is supplied; an ignition device configured to ignite the gaseous fuel in the combustion chamber; a control device that controls the execution of an ignition operation at a predetermined ignition timing of the ignition device, the predetermined ignition timing includes an initial ignition timing at which an ignition operation is performed for the first time in one combustion cycle, and a later ignition timing at which an ignition operation is performed after the initial ignition timing in the one combustion cycle, a misfire detection device that detects misfire in the combustion chamber during one combustion cycle, The control device When the misfire detection device detects a misfire in the combustion chamber, the ignition device is configured to perform an ignition operation at the later ignition timing, When the misfire detection device does not detect a misfire in the combustion chamber, the ignition device is configured to stop an ignition operation at the later ignition timing, the misfire detection device is configured to determine that a misfire has occurred when a maximum pressure in the combustion chamber after the initial ignition timing and before the post-ignition timing in one combustion cycle is equal to or lower than a predetermined pressure. Internal combustion engine.

2. the later ignition timing includes a first later ignition timing at which an ignition operation is performed in a combustion stroke of the one combustion cycle; 2. The internal combustion engine according to claim 1.

3. the first post-ignition timing is within a range of 15° ATDC to 25° ATDC; 3. The internal combustion engine according to claim 2.

4. the later ignition timing includes second later ignition timing in which an ignition operation is performed during an exhaust stroke of the one combustion cycle. An internal combustion engine according to any one of claims 1 to 3.

5. The system further includes a hydrogen combustion device for combusting hydrogen contained in the gas fuel, The hydrogen combustion device is disposed in an exhaust flow path through which exhaust gas discharged from the combustion chamber flows. An internal combustion engine according to any one of claims 1 to 4.

6. the hydrogen combustion device is disposed in a region of the exhaust flow path that receives exhaust gas discharged from the combustion chamber during an exhaust stroke of one combustion cycle.

6. An internal combustion engine according to claim 5.

7. The hydrogen combustion device is a ceramic body containing ceramic.

7. An internal combustion engine according to claim 5 or 6.

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