Control device for hydrogen engine

Abstract

To suppress abnormal combustion in a hydrogen engine.SOLUTION: A hydrogen engine includes a supercharger and a plurality of cylinders. A control device for the hydrogen engine repeatedly sets a target fuel injection amount on the basis of target engine torque. The control device repeatedly determines whether or not abnormal combustion that is an abnormality indicating that combustion occurs at timing different from ignition timing occurs (S300). On the condition that the abnormal combustion occurs in two or more of the plurality of cylinders, the control device executes intake system abnormality determination processing (Yes in S300, S302). The intake system abnormality determination processing is processing for determining whether or not intake system abnormality that is an abnormality indicating that an air amount to be supplied to the plurality of cylinders becomes small has occurred. When determining that the intake system abnormality has occurred, the control device restricts the target fuel injection amount (Yes in S304, S306).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a control device for a hydrogen engine. [Background technology]

[0002] Patent Document 1 discloses a control device for a hydrogen engine, which sets a target fuel injection amount based on a target engine torque. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-250056 Summary of the Invention [Problem to be solved by the invention]

[0004] The target fuel injection amount is set to be proportional to the target engine torque. During operation of a hydrogen engine, sufficient air is normally supplied to the cylinders of the hydrogen engine to perform lean combustion.

[0005] For example, in a hydrogen engine equipped with a turbocharger, an abnormality may occur in which the wastegate valve cannot be closed. In such a case, the turbocharger's turbine wheel cannot be sufficiently rotated by the exhaust gas, which prevents sufficient air from being sent to the cylinders. A similar phenomenon can also occur when an abnormality occurs in the exhaust passage upstream of the turbine wheel, causing exhaust gas to leak from the exhaust passage.

[0006] In such cases, the actual amount of air may be excessively less than the amount of air required for lean combustion. If the air-fuel ratio becomes rich in this way, there is a high possibility that abnormal combustion such as knocking and / or pre-ignition may occur. It is desirable to minimize such abnormal combustion. [Means for solving the problem]

[0007] The means for solving the above problems and their effects will be described below. According to one aspect of the present disclosure, there is provided a control device for a hydrogen engine that is equipped with a turbocharger and controls a hydrogen engine having multiple cylinders, the control device comprising a processing circuit, the processing circuit configured to repeatedly set a target fuel injection amount based on a target engine torque, the processing circuit configured to repeatedly determine whether abnormal combustion has occurred, which is an abnormality in which combustion occurs at a time different from the ignition timing, and the processing circuit configured to determine whether an intake system abnormality has occurred, which is an abnormality in which the amount of air supplied to the multiple cylinders is reduced, on the condition that it has determined that the abnormal combustion has occurred in two or more of the multiple cylinders, and the processing circuit configured to limit the target fuel injection amount if it is determined that the intake system abnormality has occurred. [Effects of the Invention]

[0008] According to the above configuration, abnormal combustion can be suppressed. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing a hydrogen engine and a control device that controls the hydrogen engine. [Figure 2] FIG. 2 is a flowchart showing the process executed by the control device shown in FIG. [Figure 3] FIG. 3 is a flowchart showing a process executed by the control device shown in FIG. [Figure 4] FIG. 4 is a flowchart showing the intake system abnormality determination process shown in FIG. [Figure 5] FIG. 5 is a graph of the λ limits referenced in the process shown in FIG. [Figure 6] FIG. 6 is a time chart for explaining the operation. [Figure 7]FIG. 7 is a flowchart showing the intake system abnormality determination process according to the modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] A control device for a hydrogen engine according to an embodiment will be described below with reference to the drawings. <Configuration of Hydrogen Engine 10> First, the configuration of the hydrogen engine 10, which is controlled by the control device 30 for the hydrogen engine 10, will be described with reference to FIG. 1. The hydrogen engine 10 has multiple cylinders 11. FIG. 1 shows only one of the multiple cylinders 11. An air-fuel mixture is combusted in each of the multiple cylinders 11. The hydrogen engine 10 also has an intake passage 12, which is a passage through which intake air is introduced into the cylinder 11, and an exhaust passage 13, which is a passage through which exhaust gas is discharged from the cylinder 11. The hydrogen engine 10 also has an in-cylinder injector 14, which injects fuel into the cylinder 11 to form an air-fuel mixture. The in-cylinder injector 14 is configured so that the fuel passage opens when a valve body lifts inward. In other words, the in-cylinder injector 14 is an in-valve injector. The hydrogen engine 10 also has an ignition device 15, which ignites the air-fuel mixture in the cylinder 11 by spark discharge. A throttle valve 16 is installed in the intake passage 12 downstream of the compressor wheel 21. By changing the opening of the throttle valve 16, it is possible to adjust the amount of intake air introduced into the cylinders 11. The hydrogen engine 10 generates driving force for the vehicle by rotating the crankshaft 17 through combustion of the air-fuel mixture in the cylinders 11.

[0011] The hydrogen engine 10 is equipped with a supercharger 20. In this embodiment, the supercharger 20 is a so-called turbocharger. The supercharger 20 has a compressor wheel 21 installed in the intake passage 12 and a turbine wheel 22 installed in the exhaust passage 13. The compressor wheel 21 is an impeller that compresses the intake air as it rotates. The turbine wheel 22 is an impeller that rotates in response to the exhaust flow. The compressor wheel 21 and the turbine wheel 22 are connected via a turbine shaft 23. Therefore, the compressor wheel 21 rotates in conjunction with the rotation of the turbine wheel 22.

[0012] The exhaust passage 13 is provided with a bypass passage 24, which is a passage for allowing exhaust gas to flow downstream, bypassing the turbine wheel 22. The bypass passage 24 branches off from the exhaust passage 13 at a location in the exhaust passage 13 upstream of the turbine wheel 22. The bypass passage 24 merges with the exhaust passage 13 at a location in the exhaust passage 13 downstream of the turbine wheel 22. A catalytic device 39 having a catalyst carrier 19 on which an exhaust purification catalyst is supported is provided downstream of the junction of the bypass passage 24 and the exhaust passage 13.

[0013] A wastegate valve 25 that opens and closes the outlet of the bypass passage 24 is provided in the exhaust passage 13. The wastegate valve 25 is installed downstream of the joint position of the bypass passage 24 and the exhaust passage 13 in the exhaust passage 13 and upstream of the catalytic device 39. An exhaust temperature sensor 18 that detects the exhaust temperature is provided in the exhaust passage 13. The exhaust temperature sensor 18 is installed downstream of the wastegate valve 25 in the exhaust passage 13 and upstream of the catalytic device 39.

[0014] The wastegate valve 25 is provided at the outlet of the bypass passage 24. The bypass passage 24 is opened and closed by the wastegate valve 25. When the wastegate valve 25 is open, a portion of the exhaust upstream of the turbine wheel 22 communicates with a portion of the exhaust downstream of the turbine wheel 22. When the wastegate valve 25 is open, exhaust flows through the bypass passage 24. The exhaust flowing through the bypass passage 24 does not contribute to the rotation of the turbine wheel 22. The larger the opening of the wastegate valve 25, the greater the flow rate of exhaust bypassing the turbine wheel 22. As a result, the boost pressure generated by driving the turbocharger 20 decreases.

[0015] <Configuration of the control device 30> The hydrogen engine 10 is controlled by a control device 30. The control device 30 includes a control unit 31 and a ROM (Read Only Memory) 32. The control unit 31 includes a CPU (Central Processing Unit) and RAM (Random Access Memory). The ROM 32 stores programs and data for controlling the hydrogen engine 10. The control unit 31 controls the hydrogen engine 10 by reading and executing programs from the ROM 32.

[0016] The control device 30 receives the detection results of various sensors for detecting the operating conditions of the hydrogen engine 10. The various sensors include an air flow meter 33, a vehicle speed sensor 34, an accelerator position sensor 35, a crank angle sensor 36, a boost pressure sensor 37, an in-cylinder pressure sensor 38, and an exhaust temperature sensor 18.

[0017] The air flow meter 33 is a sensor that detects the intake air volume, which is the flow rate of intake air flowing through the intake passage 12. In this embodiment, the air flow meter 33 is located upstream of the compressor wheel 21 in the intake passage 12. The vehicle speed sensor 34 is a sensor that detects the vehicle speed. The accelerator position sensor 35 is a sensor that detects the depression amount of the accelerator pedal. The crank angle sensor 36 is a sensor that detects the crank angle, which is the rotation angle of the crankshaft 17. The boost pressure sensor 37 is a sensor that detects the boost pressure, which is the pressure of the intake air in a portion of the intake passage 12 downstream of the compressor wheel 21 and upstream of the throttle valve 16. The in-cylinder pressure sensor 38 is a sensor that detects the in-cylinder pressure, which is the pressure inside the cylinder 11. The control unit 31 of the control device 30 controls the opening degree of the wastegate valve 25 based on the detection results of these sensors. Based on the detection results of these sensors, the control unit 31 controls the fuel injection amount and fuel injection timing of the in-cylinder injector 14, the ignition timing of the ignition device 15, the throttle opening, and the like.

[0018] <Processing Executed by the Control Device 30> The processing executed by the control device 30 will be described with reference to FIGS. The process of FIG. 2 is initiated when the hydrogen engine 10 is started. While the hydrogen engine 10 is running, the control device 30 repeatedly performs the process shown in FIG. 2. In step S200, the control device 30 calculates a target engine torque. For example, the control device 30 calculates the target engine torque based on the accelerator depression amount obtained from the accelerator position sensor 35. Next, the control device 30 proceeds to step S202. In step S202, the control device 30 sets the target fuel injection amount based on the target engine torque. In this embodiment, the control device 30 calculates the target fuel injection amount by multiplying the target engine torque by a constant coefficient. In this way, the control device 30 repeatedly sets the target fuel injection amount based on the target engine torque.

[0019] The process of FIG. 3 is initiated when the hydrogen engine 10 is started. In step S300, the control device 30 determines whether abnormal combustion has occurred in two or more cylinders 11. Abnormal combustion is an abnormality in which combustion occurs at a time different from the ignition timing. For example, abnormal combustion can be pre-ignition and / or knocking. The control device 30 can determine whether abnormal combustion has occurred based on the crank angle obtained from the crank angle sensor 36 and the in-cylinder pressure obtained from the in-cylinder pressure sensor 38. For example, the control device 30 determines that abnormal combustion has occurred when the in-cylinder pressure is greater than a threshold value within a predetermined crank angle range excluding top dead center. Alternatively, the control device 30 may determine whether abnormal combustion has occurred based on an ion current detected by collecting positive ions generated during combustion. If the control device 30 makes a negative determination in step S300 (S300: NO), the control device 30 repeats the process of step S300. When the control device 30 makes a positive determination in step S300 (S300: YES), the control device 30 proceeds to step S302. In step S300, the control device 30 repeatedly determines whether abnormal combustion, which is an abnormality in which combustion occurs at a time different from the ignition timing, is occurring in two or more cylinders 11. The control device 30 executes the intake system abnormality determination process of step S302 on the condition that it is determined that abnormal combustion has occurred in two or more of the multiple cylinders 11.

[0020] 4 and 5, the intake system abnormality determination process executed by the control device 30 in step S302 will be described. The intake system abnormality determination process is a process for determining whether an intake system abnormality has occurred. An intake system abnormality is an abnormality that reduces the amount of air supplied to multiple cylinders 11. Two types of abnormalities that reduce the amount of air supplied to multiple cylinders 11 will be described next. The first type of abnormality is an abnormality that prevents the wastegate valve 25 from closing. For example, if all of the exhaust gas needs to contribute to the rotation of the turbine wheel 22, the wastegate valve 25 needs to be closed. If the first type of abnormality occurs, the turbine wheel 22 cannot be sufficiently rotated by the exhaust gas. This reduces the amount of air supplied to the cylinders 11. The second type of abnormality is an abnormality that causes exhaust gas to leak from a location upstream of the turbine wheel 22 in the exhaust passage 13. In such a case, the rotation speed of the turbine wheel 22 decreases by the amount of exhaust gas leaked. This reduces the amount of air supplied to the cylinders 11.

[0021] In step S400, the control device 30 calculates the λ limit. The λ limit is the limit value of λ, which is the air excess ratio. First, the air excess ratio will be explained. The air excess ratio is the value obtained by dividing the actual air mass by the minimum air mass. The actual air mass is the mass of air actually supplied to the cylinder 11. The minimum air mass is the mass of air required to perform combustion in the cylinder 11 at the stoichiometric air-fuel ratio. The air excess ratio is an index that represents the degree of air surplus in the air-fuel mixture. The air excess ratio is equal to the value obtained by dividing the actual air-fuel ratio by the stoichiometric air-fuel ratio. When λ=1, the air-fuel ratio is the stoichiometric air-fuel ratio. When λ>1, the air-fuel ratio is leaner than the stoichiometric air-fuel ratio. When λ<1, the air-fuel ratio is richer than the stoichiometric air-fuel ratio.

[0022] During operation of the hydrogen engine 10, sufficient air is normally supplied to the cylinders 11 to perform lean combustion. If the amount of air supplied to the cylinders 11 is excessively reduced, the likelihood of abnormal combustion increases. As shown in FIG. 5, the λ limit is calculated according to the rotational speed of the hydrogen engine 10. For example, the λ limit is calculated using a map that associates the rotational speed of the hydrogen engine 10 with the λ limit. This map was obtained in advance through experiments. These experiments have shown that the likelihood of abnormal combustion increases when the excess air ratio falls below the λ limit.

[0023] As shown by the solid line in Figure 5, the λ limit increases as the rotational speed of the hydrogen engine 10 increases. The λ limit is determined by the requirements for suppressing knocking, shown by the dashed line, and the requirements for suppressing pre-ignition, shown by the dotted line. As described above, when the excess air ratio falls below the λ limit, the possibility of abnormal combustion increases. The λ limit can be expressed using a Max function: λ limit = Max {limit value of the excess air ratio determined for suppressing knocking, limit value of the excess air ratio determined for suppressing pre-ignition}. The Max function used here is a function that returns the maximum value of multiple arguments. In the low rotational speed range, the limit value of the excess air ratio determined for suppressing knocking is greater than the limit value of the excess air ratio determined for suppressing pre-ignition. In the high rotational speed range, the limit value of the excess air ratio determined for suppressing knocking is smaller than the limit value of the excess air ratio determined for suppressing pre-ignition. The requirements for suppressing knocking, shown by the dashed line, will be explained next. As the air-fuel ratio becomes richer, combustion begins earlier and the combustion temperature increases. For this reason, there is a greater need to set the air-fuel ratio leaner in the high rotation speed range than in the low rotation speed range. In other words, the limit value for the excess air ratio is higher in the high rotation speed range than in the low rotation speed range. Next, we will explain the requirements from the perspective of suppressing pre-ignition, indicated by the dashed dotted line. Pre-ignition occurs due to, for example, residual flame or residual gas. Residual flame is more difficult to extinguish in the high rotation speed range than in the low rotation speed range. In addition, the residual combustion temperature is higher in the high rotation speed range than in the low rotation speed range, so the temperature of the residual gas is also higher. Therefore, there is a greater need to set the air-fuel ratio leaner in the high rotation speed range than in the low rotation speed range.

[0024] Returning to FIG. 4, after calculating the λ limit in step S400, the control device 30 proceeds to step S402. In step S402, the control device 30 calculates the limit injection amount. The limit injection amount is calculated by dividing the actual air mass by a value obtained by multiplying the λ limit by the stoichiometric air-fuel ratio. The actual air mass can be calculated from the intake air amount detected by the air flow meter 33. Because the limit injection amount is proportional to the actual air mass, it decreases as the intake air amount detected by the air flow meter 33 decreases. Next, the control device 30 proceeds to step S404.

[0025] As described above, when the excess air ratio falls below the λ limit, the possibility of abnormal combustion increases. The limit injection amount is inversely proportional to the λ limit. Therefore, if the target fuel injection amount is greater than the limit injection amount, the possibility of abnormal combustion increases. The limit injection amount decreases as the rotation speed of the hydrogen engine 10 increases. In step S404, the control device 30 determines whether the target fuel injection amount is greater than the limit injection amount. If the determination in step S404 is affirmative (S404: YES), the control device 30 proceeds to step S406. In step S406, the control device 30 determines that the above-mentioned intake system abnormality has occurred. Thus, according to steps S404 and S406, the control device 30 determines that an intake system abnormality has occurred if the target fuel injection amount is greater than the limit injection amount. After completing the processing of step S406 or after making a negative determination in step S404 (S404: NO), the control device 30 ends the flow of FIG. 4.

[0026] Returning to FIG. 3, after processing step S302, the control device 30 proceeds to step S304. If the control device 30 determines that an intake system abnormality has occurred in the intake system abnormality determination process (S304: YES), the control device 30 proceeds to step S306. As described with reference to FIG. 2, the control device 30 sets the target fuel injection amount based on the target engine torque. In step S306, the control device 30 limits the target fuel injection amount by limiting the target engine torque to a torque limit value or less. The torque limit value decreases as the rotational speed of the hydrogen engine 10 increases. For example, the torque limit value is determined in advance through experiments so that the in-cylinder pressure is equal to or less than a predetermined value when the target engine torque is equal to or less than the torque limit value. The predetermined value may be determined in advance to avoid damage to the in-cylinder injector 14. Thus, according to steps S302 to S306, if the control device 30 determines that an intake system abnormality has occurred, the control device 30 limits the target fuel injection amount by limiting the target engine torque to a torque limit value or less. After completing the process of step S306 or after making a negative determination in step S304 (S304: NO), the control device 30 ends the flow of FIG.

[0027] <Operation of this embodiment> The operation of this embodiment will be described with reference to Figure 6. A case will be described in which the above-mentioned second type of abnormality suddenly occurs at time T1 while the hydrogen engine 10 is operating in a steady state. In this steady state, the target fuel injection amount has settled to a constant value. Also, the wastegate valve 25 is closed. At time T1, abnormal combustion is not occurring in two or more cylinders 11.

[0028] From time T1 to time T2, the rotation of the turbine wheel 22 decreases, causing the intake air amount to decrease. Therefore, from time T1 to time T2, the limit injection amount decreases. At time T2, the target fuel injection amount becomes larger than the limit injection amount. In FIG. 6, the limit injection amount is indicated by a dashed line. The control device 30 calculates the limit injection amount when abnormal combustion occurs in two or more cylinders 11 (S300: YES, S402). In FIG. 6, the limit injection amount before abnormal combustion occurs in two or more cylinders 11 is also indicated by a dashed line.

[0029] At time T3, abnormal combustion occurs in two or more cylinders 11. Also, the target fuel injection amount is greater than the limit injection amount. Therefore, the determinations in steps S300 and S404 are affirmative. As a result, from time T4 onwards, the target fuel injection amount is limited (S306).

[0030] <Effects of this embodiment> (1) The hydrogen engine 10 is equipped with a turbocharger 20 and has multiple cylinders 11. A control device 30 for the hydrogen engine 10 controls the hydrogen engine 10. The control device 30 repeatedly sets a target fuel injection amount based on a target engine torque (S202). The control device 30 repeatedly determines whether abnormal combustion, which is an abnormality in which combustion occurs at a time other than the ignition timing, is occurring (S300). The control device 30 executes an intake system abnormality determination process on the condition that it is determined that abnormal combustion has occurred in two or more of the multiple cylinders 11 (S300: YES, S302). The intake system abnormality determination process is a process for determining whether an intake system abnormality, which is an abnormality in which the amount of air supplied to the multiple cylinders 11 is reduced, has occurred. If it is determined that an intake system abnormality has occurred, the control device 30 limits the target fuel injection amount (S304: YES, S306).

[0031] When abnormal combustion occurs in two or more cylinders 11, there is a high possibility that an intake system abnormality has occurred, which is an abnormality in the intake system that reduces the amount of air supplied to the multiple cylinders 11. Therefore, when abnormal combustion occurs in two or more cylinders 11, the control device 30 determines whether an intake system abnormality has occurred.

[0032] When it is determined that an intake system abnormality has occurred, the control device 30 limits the target fuel injection amount. This makes it possible to prevent the air-fuel ratio from becoming rich. Therefore, when an intake system abnormality has occurred, it is possible to prevent abnormal combustion.

[0033] The in-cylinder injector 14 is an injector with an internal opening valve. Therefore, if the in-cylinder pressure becomes too high due to pre-ignition, there is a possibility that combustion gas will flow into the in-cylinder injector 14. If combustion gas flows into the in-cylinder injector 14, there is a possibility that the in-cylinder injector 14 will be damaged. According to the above embodiment, abnormal combustion can be suppressed, and therefore the possibility of damage to the in-cylinder injector 14 can also be reduced.

[0034] (2) The control device 30 determines whether the target fuel injection amount is greater than the limit injection amount on the condition that abnormal combustion has occurred in two or more of the cylinders 11 (S300: YES, S404). If the target fuel injection amount is greater than the limit injection amount, the control device 30 determines that an intake system abnormality has occurred (S404: YES, S406). The limit injection amount decreases as the intake amount detected by the air flow meter 33 decreases (S402).

[0035] The control device 30 sets the target fuel injection amount based on the target engine torque. Normally, when the hydrogen engine 10 is running, sufficient air is supplied to the multiple cylinders 11 to perform lean combustion. Therefore, the target fuel injection amount is usually equal to or less than the limit injection amount. In such cases, the possibility of abnormal combustion occurring is sufficiently low.

[0036] Therefore, when the target fuel injection amount is greater than the limit injection amount, the control device 30 determines that an abnormality has occurred in the intake system. According to the above configuration, it is possible to determine whether an abnormality has occurred in the intake system by comparing the target fuel injection amount with the limit injection amount.

[0037] (3) The limit injection amount decreases as the rotation speed of the hydrogen engine 10 increases (S402, FIG. 5). As the rotation speed of the hydrogen engine 10 increases, the temperature of the hydrogen engine 10 also increases. Therefore, as the rotation speed of the hydrogen engine 10 increases, abnormal combustion becomes more likely to occur. Therefore, as the rotation speed of the hydrogen engine 10 increases, there is an increasing demand to make the air-fuel ratio leaner in order to suppress the occurrence of abnormal combustion.

[0038] With the above configuration, the limit injection amount decreases as the rotation speed of the hydrogen engine 10 increases and abnormal combustion becomes more likely to occur. Therefore, the change in the likelihood of abnormal combustion occurring due to changes in the rotation speed of the hydrogen engine 10 can be reflected in the determination of whether an intake system abnormality has occurred.

[0039] (4) When it is determined that an abnormality has occurred in the intake system, the control device 30 limits the target fuel injection amount by limiting the target engine torque to a torque limit value or less (S306). The torque limit value becomes smaller as the rotation speed of the hydrogen engine 10 increases.

[0040] As the rotation speed of the hydrogen engine 10 increases, the need to make the air-fuel ratio leaner in order to suppress the occurrence of abnormal combustion increases. With the above configuration, the torque limit value decreases as the rotation speed of the hydrogen engine 10 increases. Therefore, the rotation speed of the hydrogen engine 10 can be reflected in the degree to which the target fuel injection amount is limited in order to suppress the occurrence of abnormal combustion.

[0041] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0042] In the above embodiment, the control device 30 executes the intake system abnormality determination process on the condition that it determines that abnormal combustion has occurred in two or more of the multiple cylinders 11. For example, the control device 30 may execute the intake system abnormality determination process on the condition that it determines that abnormal combustion has occurred in three or more of the multiple cylinders 11. The number of cylinders 11 in which abnormal combustion has occurred, which is counted to determine whether or not to execute the intake system abnormality determination process, may be changed depending on the number of multiple cylinders 11 included in the hydrogen engine 10.

[0043] In the above embodiment, the control device 30 limits the target fuel injection amount by limiting the target engine torque to a torque limit value or less. Alternatively, the control device 30 may directly limit the target fuel injection amount. For example, the control device 30 may limit the target fuel injection amount so that the excess air ratio is equal to or greater than a desired excess air ratio.

[0044] In the above embodiment, the intake system abnormality determination process has been described with reference to Fig. 4. However, the intake system abnormality determination process shown in Fig. 4 is merely an example. Next, the intake system abnormality determination process according to the modified example will be described with reference to FIG. 7. In step S700, the control device 30 determines whether the boost pressure is smaller than a value obtained by subtracting a margin from the target boost pressure. The boost pressure can be obtained from the boost pressure sensor 37. The target boost pressure is calculated based on the accelerator depression amount obtained from the accelerator position sensor 35, etc. The margin is determined appropriately in advance. If the control device 30 makes a positive determination in step S700 (S700: YES), the process proceeds to step S702. In step S702, the control device 30 determines that an intake system abnormality has occurred. After completing the process of step S702, or if the control device 30 makes a negative determination in step S700 (S700: NO), the control device 30 ends the flow of FIG. 7. The configuration of FIG. 7 makes it possible to determine the occurrence of an intake system abnormality related to the above-described first type abnormality and second type abnormality. It is also possible to determine the occurrence of an intake system abnormality related to air leakage from a location in the intake passage 12 between the compressor wheel 21 and the supercharging pressure sensor 37.

[0045] The process of step S700 in Figure 7 may be changed to a process of determining whether the actual engine load factor is smaller than the value obtained by subtracting the margin from the target engine load factor. Here, the engine load factor is a value that indicates the ratio of the current intake air amount to the maximum intake air amount corresponding to the rotation speed of the hydrogen engine 10. Therefore, when the intake air amount is equal to the maximum value, the engine load factor is "100%."

[0046] The process of step S700 in FIG. 7 may be changed to a process of determining whether or not the actual torque is smaller than the value obtained by subtracting the margin from the target torque. The processing of step S700 in FIG. 7 can be changed to processing that determines whether a logical AND condition consisting of two or more of the following conditions (A), (B), and (C) is satisfied. Condition (A) is a condition that the boost pressure is smaller than the value obtained by subtracting the margin from the target boost pressure. Condition (B) is a condition that the actual engine load factor is smaller than the value obtained by subtracting the margin from the target engine load factor. Condition (C) is a condition that the actual torque is smaller than the value obtained by subtracting the margin from the target torque.

[0047] The process of step S700 in FIG. 7 can be changed to a process of determining whether or not a logical sum condition consisting of two or more of the above conditions (A), (B), and (C) is satisfied. In the above embodiment, the air flow meter 33 is located upstream of the compressor wheel 21 in the intake passage 12. Alternatively, the air flow meter 33 may be located downstream of the compressor wheel 21 in the intake passage 12. In this case, it is possible to determine the occurrence of an intake system abnormality related to air leakage from a location in the intake passage 12 between the compressor wheel 21 and the boost pressure sensor 37.

[0048] In the above embodiment, the supercharger 20 is a turbocharger. Alternatively, the supercharger 20 may be a supercharger. The supercharger supplies compressed air to the cylinders 11 by driving a compressor with power extracted from the crankshaft 17 of the hydrogen engine 10 via a belt. The compressor may be driven by an electric motor. The air flow meter 33 may be located downstream of the compressor in the intake passage 12. In this case, it is possible to determine the occurrence of an intake system abnormality related to air leakage from a portion of the intake passage 12 between the compressor and the air flow meter 33.

[0049] In the above embodiment, the control device 30 includes a control unit 31 and a ROM 32. The control unit 31 includes a CPU and a RAM. The control device 30 executes software processing. However, this is merely an example. For example, the control device 30 may include a dedicated hardware circuit (e.g., an ASIC) that processes at least a portion of the software processing executed in the above embodiment. That is, the control device 30 may have any of the following configurations (a) to (c): (a) The control device 30 includes a processing device that executes all processing according to a program and a program storage device such as a ROM that stores the program. That is, the control device 30 includes a software execution device. (b) The control device 30 includes a processing device that executes a portion of the processing according to a program and a program storage device. Furthermore, the control device 30 includes a dedicated hardware circuit that executes the remaining processing. (c) The control device 30 includes a dedicated hardware circuit that executes all processing. Here, there may be multiple software execution devices and / or dedicated hardware circuits. That is, the above processing may be executed by processing circuitry that includes at least one of a software execution device and a dedicated hardware circuit. The processing circuitry may include multiple software execution devices and dedicated hardware circuits. Program storage devices or computer-readable media include storage devices that are any available media that can be accessed by a general purpose or special purpose computer. [Explanation of symbols]

[0050] 10... hydrogen engine, 11... cylinder, 20... turbocharger, 30... control device, 33... air flow meter

Claims

1. A control device for a hydrogen engine that is equipped with a supercharger and controls a hydrogen engine having multiple cylinders, a processing circuit; the processing circuitry is configured to repeatedly set a target fuel injection amount based on a target engine torque; The processing circuit is configured to repeatedly determine whether abnormal combustion, which is an abnormality in which combustion occurs at a timing other than the ignition timing, is occurring, the processing circuit is configured to determine whether an intake system abnormality has occurred, which is an abnormality that reduces the amount of air supplied to the plurality of cylinders, on condition that it has been determined that the abnormal combustion has occurred in two or more of the plurality of cylinders; The processing circuit is configured to limit the target fuel injection amount when it is determined that the intake system abnormality has occurred. Hydrogen engine control device.

2. the processing circuit is configured to determine whether the target fuel injection amount is greater than a limit injection amount on condition that it is determined that the abnormal combustion has occurred in two or more of the plurality of cylinders, the processing circuit is configured to determine that the intake system abnormality has occurred when the target fuel injection amount is greater than the limit injection amount, The limit injection amount decreases as the intake amount detected by the air flow meter decreases. The control device for a hydrogen engine according to claim 1.

3. The limit injection amount decreases as the rotation speed of the hydrogen engine increases. The control device for a hydrogen engine according to claim 2.

4. the processing circuit is configured to limit the target fuel injection amount by limiting the target engine torque to a torque limit value or less when it is determined that the intake system abnormality has occurred, The torque limit value decreases as the rotational speed of the hydrogen engine increases. The control device for a hydrogen engine according to claim 1.

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