Internal combustion engine abnormality detection device

Abstract

To determine a fuel system that has a leakage abnormality.SOLUTION: A fuel supply device 200 for an internal combustion engine 10 includes: a first fuel system FL1 that is a fuel system between a first shut-off valve 21 and a second shut-off valve 22; and a second fuel system FL2 that is a fuel system between the second shut-off valve 22 and a fuel injection valve 15. A control device 100 executes determination processing for determining whether the first fuel system FL1 has a leakage abnormality or the second fuel system FL2 has a leakage abnormality on the basis of a magnitude relation between a detection value obtained by a first pressure sensor 81 while the first fuel system FL1 is filled with gaseous fuel and a prescribed first threshold value and a magnitude relation between a detection value obtained by a second pressure sensor 82 while the second fuel system FL2 is filled with gaseous fuel and a prescribed second threshold value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] For example, the internal combustion engine described in Patent Document 1 includes, in order from upstream, a first shutoff valve, a second shutoff valve, and a pressure reducing valve in a fuel passage connecting a tank that stores gaseous fuel and a fuel injection valve that injects the gaseous fuel. The fuel passage between the first and second shutoff valves is also provided with a pressure sensor. The pressure sensor detects abnormalities in the high-pressure piping upstream of the pressure reducing valve or in the first shutoff valve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-90076 Summary of the Invention [Problem to be solved by the invention]

[0004] However, depending on the sealing condition of the nozzle hole of the fuel injection valve that injects gaseous fuel, it is not always possible to seal the nozzle hole when the internal combustion engine is stopped. Therefore, in order to reduce the amount of gaseous fuel leaking from the nozzle hole into the cylinder when the engine is stopped, it is possible to position the above-mentioned second shutoff valve between the fuel injection valve and the pressure reducing valve. In a fuel system with a shutoff valve in such a position, it is desirable to be able to determine whether a leakage abnormality is occurring in the fuel system between the first shutoff valve and the second shutoff valve, or in the fuel system between the second shutoff valve and the fuel injection valve. However, the system described in Patent Document 1 detects a leakage abnormality in the fuel system upstream of the pressure reducing valve, making such a determination difficult. [Means for solving the problem]

[0005] An abnormality detection device for an internal combustion engine that solves the above problem is an abnormality detection device for an internal combustion engine that is equipped with a fuel supply device that has a tank for storing gaseous fuel, a fuel injection valve that supplies fuel to a cylinder, a fuel passage that supplies the gaseous fuel in the tank to the fuel injection valve, a first shut-off valve provided in the fuel passage downstream of the tank, a pressure reducing valve provided in the fuel passage downstream of the first shut-off valve, a second shut-off valve provided in the fuel passage downstream of the pressure reducing valve, a first pressure sensor provided in a first fuel system that is a fuel system between the first shut-off valve and the second shut-off valve, and a second pressure sensor provided in a second fuel system that is a fuel system between the second shut-off valve and the fuel injection valve. This abnormality detection device performs a determination process to determine whether there is a leak abnormality in the first fuel system or the second fuel system based on the magnitude relationship between the detection value of the first pressure sensor when the first fuel system is filled with gaseous fuel and a predetermined first threshold value, and the magnitude relationship between the detection value of the second pressure sensor when the second fuel system is filled with gaseous fuel and a predetermined second threshold value.

[0006] According to this configuration, a pressure sensor is provided in each of the first fuel system between the first shutoff valve and the second shutoff valve, and the second fuel system between the second shutoff valve and the fuel injector. If there is a leak in the first fuel system or the second fuel system, the leak will be reflected in the detection values ​​of the pressure sensors. Therefore, this configuration executes the above-described determination process. Therefore, it becomes possible to determine whether the fuel leak is occurring in the first fuel system or the second fuel system based on the magnitude relationship between the detection values ​​of the pressure sensors and a predetermined threshold value. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram showing a fuel system and a control device of an internal combustion engine in a first embodiment. [Figure 2] 4 is a flowchart showing the procedure of a determination process executed by the control device of the embodiment. [Figure 3] 10 is a flowchart showing the procedure of a determination process executed by a control device of a second embodiment. [Figure 4] 10 is a flowchart showing the procedure of a determination process executed by a control device of a third embodiment. [Figure 5] 10 is a flowchart showing the procedure of a determination process executed by a control device of a fourth embodiment. [Figure 6] 10 is a flowchart showing the procedure of a determination process executed by a control device of a fifth embodiment. [Figure 7] 13 is a flowchart showing the procedure of a determination process executed by a control device of a sixth embodiment. [Figure 8] 10 is a flowchart showing the procedure of a determination process executed by a control device in a modification of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] (First embodiment) A first embodiment of an abnormality detection device for an internal combustion engine will be described below with reference to FIGS.

[0009] <Regarding fuel systems and control devices for internal combustion engines> The internal combustion engine 10 shown in FIG. 1 is an internal combustion engine that uses hydrogen gas as a gaseous fuel. The fuel supply device 200 provided in the internal combustion engine 10 includes a fuel injection valve 15, a tank 20, a fuel pipe 40, a first shutoff valve 21, a second shutoff valve 22, a pressure reducing valve 30, and a delivery pipe 60.

[0010] The fuel injection valve 15 supplies fuel to the cylinders of the internal combustion engine 10 . The tank 20 stores hydrogen gas, which is a gaseous fuel, in a compressed state. The fuel pipe 40 is connected to the tank 20 and the delivery pipe 60 .

[0011] The fuel injection valve 15 is connected to the delivery pipe 60 . The hydrogen gas stored in the tank 20 is supplied to the fuel injection valve 15 via the fuel pipe 40 and the delivery pipe 60 .

[0012] In the fuel pipe 40, a first shutoff valve 21, a pressure reducing valve 30, and a second shutoff valve 22 are arranged in this order in the direction of fuel flow. The first shutoff valve 21 is an electromagnetic valve and is disposed near the outlet of the tank 20. When the first shutoff valve 21 is open, fuel is supplied from the tank 20 to the fuel pipe 40. When the first shutoff valve 21 is closed, fuel supply from the tank 20 to the fuel pipe 40 is stopped.

[0013] The pressure reducing valve 30 is an electromagnetic valve that adjusts the fuel pressure, which is the pressure of the hydrogen gas supplied to the fuel injection valve 15, to a pressure that corresponds to the engine operating state. The second shutoff valve 22 is an electromagnetic valve and is disposed near the delivery pipe 60. When the second shutoff valve 22 is open, fuel is supplied to the delivery pipe 60. When the second shutoff valve 22 is closed, fuel supply to the delivery pipe 60 is stopped. Furthermore, by closing the second shutoff valve 22, the amount of fuel leaking into the cylinder from the nozzle hole of the fuel injection valve 15 is reduced.

[0014] The first shut-off valve 21 and the second shut-off valve 22 are maintained in a closed state while the internal combustion engine 10 is stopped. On the other hand, the first shut-off valve 21 and the second shut-off valve 22 are maintained in an open state while the internal combustion engine 10 is operating.

[0015] In the following description, the fuel system between the first shutoff valve 21 and the second shutoff valve 22 is referred to as a first fuel system FL1. The first fuel system FL1 includes the first shutoff valve 21, the pressure reducing valve 30, and the fuel pipe 40 upstream of the second shutoff valve 22.

[0016] In addition, in this first fuel system FL1, the first shutoff valve 21 and the fuel pipe 40 upstream of the pressure reducing valve 30 are referred to as the upstream first fuel system FL1H. The fuel pressure in this upstream first fuel system FL1H is the fuel pressure before being reduced by the pressure reducing valve 30, and is high.

[0017] In addition, in the first fuel system FL1, the fuel pipe 40 between the pressure reducing valve 30 and the second shutoff valve 22 is referred to as the downstream first fuel system FL1L. The fuel pressure in this downstream first fuel system FL1L is the fuel pressure after being reduced by the pressure reducing valve 30, and is lower than the fuel pressure in the upstream first fuel system FL1H.

[0018] The fuel system between the second shutoff valve 22 and the fuel injection valve 15 is referred to as the second fuel system FL2. The second fuel system FL2 includes the second shutoff valve 22, the fuel injection valve 15, and a fuel pipe downstream of the second shutoff valve 22, such as the delivery pipe 60 and the fuel pipe 40 connecting the delivery pipe 60 and the second shutoff valve 22.

[0019] The first fuel system FL1 is provided with a first pressure sensor 81 and a third pressure sensor 83. The first pressure sensor 81 is an upstream pressure sensor provided in the fuel pipe 40 between the first shutoff valve 21 and the pressure reducing valve 30. The first pressure sensor 81 is in the first fuel system FL1 and detects a first pressure P1 which is the fuel pressure of the upstream first fuel system FL1H.

[0020] The third pressure sensor 83 is a downstream pressure sensor provided in the fuel pipe 40 between the pressure reducing valve 30 and the second shutoff valve 22. The third pressure sensor 83 is in the first fuel system FL1 and detects a third pressure P3 which is the fuel pressure of the downstream first fuel system FL1L.

[0021] The second fuel system FL2 is provided with a second pressure sensor 82. More specifically, the second pressure sensor 82 is provided in the delivery pipe 60. Therefore, the second pressure sensor 82 detects a second pressure P2, which is the fuel pressure in the delivery pipe 60.

[0022] The control device 100 performs various controls such as fuel injection for the internal combustion engine 10 by controlling various control objects such as the fuel injection valve 15, the first shutoff valve 21, the pressure reducing valve 30, and the second shutoff valve 22. The control device 100 includes a CPU 110 and a memory 120 configured from a ROM, a RAM, etc., and performs various controls by the CPU 110 executing programs stored in the memory 120.

[0023] The control device 100 refers to various values ​​required for controlling the internal combustion engine 10. For example, the control device 100 refers to the detection values ​​of the first pressure sensor 81, the second pressure sensor 82, and the third pressure sensor 83. The control device 100 also refers to a detection signal from an accelerator position sensor 71 that detects an accelerator operation amount ACCP, which is an operation amount of an accelerator pedal operated by a driver of a vehicle equipped with the internal combustion engine 10. The control device 100 also refers to a detection signal from a speed sensor 72 that detects a vehicle speed SP of the vehicle equipped with the internal combustion engine 10. In addition, the control device 100 refers to detection signals for calculating the engine rotation speed of the internal combustion engine 10, a detection signal for the intake air amount, etc.

[0024] <Process for determining fuel leak abnormalities> The control device 100 executes a determination process to determine in which of the first fuel system FL1 and the second fuel system FL2 a fuel leakage abnormality has occurred.

[0025] The fuel leakage abnormality refers to fuel leakage from the fuel pipe or fuel leakage from the first shutoff valve 21 or the second shutoff valve 22. The fuel leakage from the first shutoff valve 21 or the second shutoff valve 22 refers to a valve closing abnormality occurring in the shutoff valve, whereby the valve body cannot be closed, causing fuel to flow from upstream to downstream of the shutoff valve despite the output of a valve close command.

[0026] Figure 2 shows the procedure of the above determination process. The process shown in this Figure 2 is implemented by the CPU 110 executing a program stored in the memory 120 of the control device 100. Note that the process shown in Figure 2 is started when a start request occurs for the internal combustion engine 10 in the operation stop state, such as when the ignition switch is turned on. Also, hereinafter, the step numbers are represented by numbers with "S" attached at the beginning.

[0027] When starting this process, the control device 100 opens the first shut-off valve 21 by outputting an open valve command to the first shut-off valve 21 (S100). Next, the control device 100 closes the first shut-off valve 21 by outputting a close valve command to the first shut-off valve 21 at the timing when a predetermined fixed time has elapsed after outputting the open valve command in S100 (S110). By the processes of S100 and S110, a filling process for filling the first fuel system FL1 with gaseous fuel is performed.

[0028] Next, the control device 100 determines whether the first pressure drop amount P1C is less than or equal to the first threshold value P1Cref (S120). The first pressure drop amount P1C is a value obtained by subtracting the first pressure P1 at the time when the first shut-off valve 21 is closed in the process of S110 from the first pressure P1 at the time when a fixed time has elapsed after the first shut-off valve 21 is closed in the same process. When a leakage abnormality has occurred in the first fuel system FL1 and the fuel pressure has dropped, the value of the first pressure drop amount P1C becomes a value exceeding the above first threshold value P1Cref. The first threshold value P1Cref is a value obtained by multiplying the first pressure P1 at the time when the first shut-off valve 21 is closed in the process of S110 by a predetermined coefficient K1. The coefficient K1 is a value within the range of "0 < K1 < 1" and is set in advance.

[0029] If it is determined in S120 that the first pressure drop amount P1C is less than or equal to the first threshold value P1Cref, the control device 100 opens the second shut-off valve 22 by outputting an open valve command to the second shut-off valve 22 (S130).

[0030] Next, the control device 100 closes the second shut-off valve 22 by outputting a valve closing command to the second shut-off valve 22 at the timing when a predetermined fixed time has elapsed since the valve opening command was output in S130 (S140). Through the processes of S130 and S140, a filling process for filling the second fuel system FL2 with gaseous fuel is performed.

[0031] Next, the control device 100 determines whether the second pressure drop amount P2C is less than or equal to a second threshold value P2Cref (S150). The second pressure drop amount P2C is a value obtained by subtracting the second pressure P2 at the time when the second shut-off valve 22 is closed in the process of S140 from the second pressure P2 at the time when a fixed time has elapsed after the second shut-off valve 22 is closed in the same process. When a leakage abnormality has occurred in the second fuel system FL2 and the fuel pressure has dropped, the value of the second pressure drop amount P2C becomes a value exceeding the second threshold value P2Cref. The second threshold value P2Cref is a value obtained by multiplying the second pressure P2 at the time when the second shut-off valve 22 is closed in the process of S140 by a predetermined coefficient K2. The coefficient K2 is a value within the range of "0 < K2 < 1" and is set in advance. Also, the coefficient K2 is a value larger than the coefficient K1. Since the coefficient K2 is a value larger than the coefficient K1 in this way, the second threshold value P2Cref is set so that the range in which it is determined that there is no abnormality in the pressure change amount when the pressure changes is wider than the first threshold value P1Cref.

[0032] If it is determined in S150 that the second pressure drop amount P2C is less than or equal to the second threshold value P2Cref, the control device 100 opens the first shut-off valve 21 and the second shut-off valve 22 by outputting a valve opening command to both the first shut-off valve 21 and the second shut-off valve 22 (S160). Then, the control device 100 permits the start of the internal combustion engine 10 (S170).

[0033] If it is determined in S150 that the second pressure drop amount P2C exceeds the second threshold value P2Cref, the control device 100 determines that there is a leakage abnormality in the second fuel system FL2 (S210). Then, the control device 100 prohibits the start of the internal combustion engine 10 (S220).

[0034] If it is determined in S120 above that the first pressure decrease amount P1C exceeds the first threshold value P1Cref, the control device 100 determines whether the second pressure P2 increased when the valve open command was output to the first shutoff valve 21 in S100 (S180). In S180, the control device 100 determines that the second pressure P2 has increased if the amount of pressure increase in the second pressure P2 during the period from when the valve open command was output to the first shutoff valve 21 in S100 until the elapse of a predetermined time is equal to or greater than a predetermined value.

[0035] If it is determined that the second pressure P2 has increased, the control device 100 determines that there is a leakage abnormality in the second shutoff valve 22 (S190), and then executes the process of S220 described above. If it is determined in S180 above that the second pressure P2 has not increased, the control device 100 determines that there is a leakage abnormality in the first fuel system FL1 (S200), and then executes the processing of S220 above.

[0036] Furthermore, when the process of S170 or the process of S220 is completed, the control device 100 ends this process. <Action and effect> The operation and effects of this embodiment will be described.

[0037] (1-1) Pressure sensors are provided in the first fuel system FL1 between the first shutoff valve 21 and the second shutoff valve 22, and in the second fuel system FL2 between the second shutoff valve 22 and the fuel injector 15. If there is a leakage abnormality in the first fuel system FL1 or the second fuel system FL2, such an abnormality will be reflected in the detection values ​​of these pressure sensors. Therefore, in this embodiment, the determination process shown in FIG. 2 is executed. Therefore, it is possible to determine in which fuel system, the first fuel system FL1 or the second fuel system FL2, a fuel leakage abnormality has occurred, based on the magnitude relationship between the detection values ​​of these pressure sensors and a predetermined threshold value.

[0038] More specifically, when a valve closing abnormality occurs in which the second shutoff valve 22 cannot be closed, a leakage abnormality occurs in the second shutoff valve 22. When such a leakage abnormality occurs in the second shutoff valve 22, the second shutoff valve 22 is not closed, and therefore, after the first fuel system FL1 is filled with gaseous fuel, a pressure drop occurs in the first fuel system FL1. Furthermore, when the first fuel system FL1 is filled with gaseous fuel, gaseous fuel is also supplied to the second fuel system FL2, and therefore the pressure detected by the second pressure sensor 82 increases. Therefore, in this embodiment, when the following conditions A and B are both established, it is determined in the processing of S190 that a leakage abnormality exists in the second shutoff valve 22.

[0039] Condition A: After the filling process of the first fuel system FL1 is completed, a negative determination is made in the process of S120, and a pressure drop in the first fuel system FL1 is detected. Condition B: When a valve open command is output to the first shutoff valve 21, an increase in the second pressure P2 is detected.

[0040] Therefore, a leakage abnormality in the second shutoff valve 22 of the second fuel system FL2 can be detected. (1-2) When a leakage abnormality occurs in the first fuel system FL1 upstream of the second shutoff valve 22, a pressure drop occurs in the first fuel system FL1 after the first fuel system FL1 is filled with gaseous fuel. Furthermore, if the second shutoff valve 22 is normally closed, the gaseous fuel filled in the first fuel system FL1 is not supplied to the second fuel system FL2, and therefore the second pressure P2 does not increase. Therefore, in this embodiment, when the following conditions A and C are both established, it is determined in the processing of S200 that a leakage abnormality exists in the first fuel system FL1.

[0041] Condition A: After the filling process of the first fuel system FL1 is completed, a negative determination is made in the process of S120, and a pressure drop in the first fuel system FL1 is detected. Condition C: When a valve open command is output to the first shutoff valve 21, it is detected that the second pressure P2 has not increased.

[0042] Therefore, a leakage abnormality in the first fuel system FL1 upstream of the second shutoff valve 22 can be detected. (1-3) When the second shutoff valve 22 is closed and a leakage abnormality occurs in the second fuel system FL2 downstream of the second shutoff valve 22, no pressure drop occurs in the first fuel system FL1 after the first fuel system FL1 is filled with gaseous fuel. On the other hand, a pressure drop occurs in the second fuel system FL2 after the second fuel system FL2 is filled with gaseous fuel. Therefore, in this embodiment, when the following conditions D and E are both satisfied, it is determined in the processing of S210 that a leakage abnormality exists in the second fuel system FL2 downstream of the second shutoff valve 22.

[0043] Condition D: After the filling process of the first fuel system FL1 is completed, a positive determination is made in the process of S120, and a pressure drop in the first fuel system FL1 is not detected. Condition E: After the second fuel system FL2 is filled with gaseous fuel, a negative determination is made in the process of S150, and it is detected that a pressure drop has occurred in the second fuel system FL2.

[0044] Therefore, a leakage abnormality in the second fuel system FL2 downstream of the second shutoff valve 22 can be detected. (1-4) The fuel injection valve 15 that injects gaseous fuel may leak a larger amount of fuel from its nozzle hole when the valve is closed than the fuel injection valve that injects liquid fuel. Therefore, when a leakage abnormality occurs in the second fuel system FL2 having the fuel injection valve 15 that injects gaseous fuel, the degree of pressure drop in the second fuel system FL2 is as follows. That is, the degree of pressure drop in the second fuel system FL2 may be larger than the degree of pressure drop in the first fuel system FL1 when a leakage abnormality occurs in the first fuel system FL1. In this regard, in the present embodiment, the coefficient K2 is set to a value larger than the coefficient K1. Therefore, the second threshold value P2Cref is set so that the range in which it is determined that there is no abnormality in the amount of pressure change is wider than the first threshold value P1Cref. Therefore, it is possible to prevent a leakage that occurs when the fuel injection valve 15 is normally closed from being erroneously determined to be a leakage in the second fuel system FL2, thereby improving the accuracy of determining a leakage abnormality.

[0045] (Second Embodiment) Next, a second embodiment of the abnormality detection device for an internal combustion engine will be described with reference to FIG. 3. (Regarding the process of determining fuel leakage abnormality in this embodiment) As shown in FIG. 3, the determination process of this embodiment is configured to change a part of the determination process described in the first embodiment. Hereinafter, the determination process of this embodiment will be described focusing on such differences. In FIG. 3, the same process as the process shown in FIG. 2 above is assigned the same step number.

[0046] As shown in FIG. 3, when a negative determination is made in the process of S120 described above, the control device 100 then executes the process of S300. In S300, the control device 100 determines whether the third pressure drop amount P3C is less than or equal to the third threshold value P3Cref.

[0047] The third pressure drop amount P3C is a value obtained by subtracting the third pressure P3 at the time when a predetermined time has elapsed after closing the first shut-off valve 21 in the process of S110 from the third pressure P3 when the first shut-off valve 21 is closed in the process of S110. When the value of the third pressure drop amount P3C exceeds the third threshold value P3Cref, a pressure drop of the third pressure P3 is detected. The third threshold value P3Cref is a value obtained by multiplying the third pressure P3 when the first shut-off valve 21 is closed in the process of S110 by a predetermined coefficient K3. The coefficient K3 is a value within the range of "0 < K3 < 1" and is set in advance.

[0048] If it is determined in S300 that the third pressure drop amount P3C is less than or equal to the third threshold value P3Cref, the control device 100 determines that there is a leakage abnormality in the upstream first fuel system FL1H of the first fuel system FL1 upstream of the pressure reducing valve 30 (S320). Then, the control device 100 executes the process of S220 described above.

[0049] On the other hand, if it is determined that the third pressure drop amount P3C exceeds the third threshold value P3Cref, the control device 100 executes the process of S180 described above. That is, the control device 100 determines whether or not the second pressure P2 increased when the open command was output to the first shutoff valve 21 in S100 described above (S180).

[0050] If it is determined that the second pressure P2 has increased, the control device 100 determines that there is a leakage abnormality in the second shutoff valve 22 (S190), and then executes the process of S220 described above. If it is determined in S180 above that the second pressure P2 has not increased, the control device 100 determines (S330) that there is a leakage abnormality in the downstream first fuel system FL1L, which is the first fuel system FL1 downstream of the pressure reducing valve 30. Then, the control device 100 executes the process of S220 above.

[0051] <Action and effect> According to this embodiment, in addition to the functions and effects of the first embodiment, the following functions and effects can be obtained.

[0052] (2-1) When there is a leakage abnormality in the first fuel system FL1 upstream of the pressure reducing valve 30, after the first fuel system FL1 is filled with gaseous fuel, a pressure drop occurs between the first shutoff valve 21 and the pressure reducing valve 30, but no pressure drop occurs between the pressure reducing valve 30 and the second shutoff valve 22. Therefore, in this embodiment, when the following conditions F and G are both established, it is determined in the processing of S320 that there is a leakage abnormality in the upstream first fuel system FL1H.

[0053] Condition F: After the filling process of the first fuel system FL1 is completed, a negative determination is made in the process of S120, and a pressure drop is detected in the first fuel system FL1 between the first shutoff valve 21 and the pressure reducing valve 30.

[0054] Condition G: Since the determination in the processing of S300 is affirmative, a pressure drop is not detected in the first fuel system FL1 between the pressure reducing valve 30 and the second shutoff valve 22. Therefore, a leakage abnormality in the upstream first fuel system FL1H, which is the first fuel system FL1 upstream of the pressure reducing valve 30, can be detected.

[0055] (2-2) If there is a leakage abnormality in the first fuel system FL1 downstream of the pressure reducing valve 30, after the first fuel system FL1 is filled with gaseous fuel, a pressure drop occurs between the first shutoff valve 21 and the pressure reducing valve 30, and a pressure drop also occurs between the pressure reducing valve 30 and the second shutoff valve 22. Here, the pressure drop between the pressure reducing valve 30 and the second shutoff valve 22 occurs even when the second shutoff valve 22 is not closed normally. Therefore, if a pressure drop occurs between the pressure reducing valve 30 and the second shutoff valve 22 even though the second shutoff valve 22 is closed normally, it can be determined that there is a leakage abnormality in the first fuel system FL1 downstream of the pressure reducing valve 30. Therefore, in this embodiment, if the following conditions F, H, and C are all satisfied, it is determined in the processing of S320 that there is a leakage abnormality in the upstream first fuel system FL1H.

[0056] Condition F: After the filling process of the first fuel system FL1 is completed, a negative determination is made in the process of S120, and a pressure drop is detected in the first fuel system FL1 between the first shutoff valve 21 and the pressure reducing valve 30.

[0057] Condition H: When a negative determination is made in the processing of S300, a pressure drop is detected in the first fuel system FL1 between the pressure reducing valve 30 and the second shutoff valve 22. Condition C: When a valve open command is output to the first shutoff valve 21, it is detected that the second pressure P2 is not rising, and the second shutoff valve 22 is normally closed.

[0058] Therefore, a leakage abnormality in the downstream first fuel system FL1L, which is the first fuel system FL1 downstream of the pressure reducing valve 30, can be detected. (Third embodiment) Next, a third embodiment of an abnormality detection device for an internal combustion engine will be described with reference to FIG.

[0059] <Process for Determining Fuel Leak Abnormality in the Present Embodiment> As shown in Fig. 4, the determination process of this embodiment is a partial modification of the determination process described in the first embodiment. The determination process of this embodiment will be described below, focusing on these differences. Note that in Fig. 4, the same steps as those shown in Fig. 2 are assigned the same step numbers.

[0060] 4, the control device 100 executes the process of S400 instead of the process of S120 described above. In S400, the control device 100 determines whether the third pressure decrease amount P3C is equal to or less than the third threshold value P3Cref.

[0061] The third pressure drop amount P3C and the third threshold value P3Cref are the same as those described in the second embodiment. Note that the third threshold value P3Cref may be a value different from that described in the second embodiment.

[0062] If the determination in S400 is affirmative, the control device 100 executes the processes from S130 onward. On the other hand, if the determination in S400 is negative, the control device 100 executes the processes from S180 onward.

[0063] <Action and effect> The operation and effects of this embodiment will be described. (3-1) The upstream first fuel system FL1H, which is provided with the first pressure sensor 81, and the downstream first fuel system FL1L, which is provided with the third pressure sensor 83, are connected via the pressure reducing valve 30. Therefore, although the first pressure P1 and the third pressure P3 have different pressure magnitudes, they exhibit the same tendency of change. Therefore, whether or not a pressure drop has occurred in the first fuel system FL1 can be determined based on either the first pressure P1 or the third pressure P3. Therefore, in this embodiment, whether or not a pressure drop has occurred in the first fuel system FL1 is determined based on the third pressure P3 after the filling process of the first fuel system FL1 is completed. Therefore, this embodiment also provides the same functions and effects as the first embodiment.

[0064] (Fourth embodiment) Next, a fourth embodiment of the abnormality detection device for an internal combustion engine will be described with reference to FIG. 5. <Regarding the process of determining fuel leakage abnormality in this embodiment> As shown in FIG. 5, the determination process of this embodiment modifies a part of the determination process described in the first embodiment. More specifically, the determination process is performed using the third pressure P3 instead of the second pressure P2. Hereinafter, the determination process of this embodiment will be described focusing on such differences. In FIG. 5, the same steps are assigned to the same processes shown in FIG. 2 above.

[0065] As shown in FIG. 5, when a positive determination is made in the process of S120 described above, the control device 100 opens the second shut-off valve 22 by executing the process of S130. Then, next, it is determined whether the third pressure drop amount P3C is less than or equal to the third threshold value P3Cref (S530).

[0066] The third pressure drop amount P3C in this S530 is a value obtained by subtracting the third pressure P3 at the time when the second shut-off valve 22 is closed in the process of S130 from the third pressure P3 at the time when a predetermined time has elapsed after the second shut-off valve 22 is closed in the same process. When the value of the third pressure drop amount P3C exceeds the third threshold value P3Cref, a pressure drop of the third pressure P3 is detected. The third threshold value P3Cref is a value obtained by multiplying the third pressure P3 when the first shut-off valve 21 is closed in the process of S130 by a predetermined coefficient K6. The coefficient K6 is a value within the range of "0 < K6 < 1" and is preset.

[0067] Then, when it is determined in S530 that the third pressure drop amount P3C is less than or equal to the third threshold value P3Cref, the first shut-off valve 21 is opened by outputting an opening command to the first shut-off valve 21 (S540). Then, the process of S170 is executed.

[0068] On the other hand, if it is determined in S530 that the third pressure drop amount P3C exceeds the third threshold value P3Cref, the control device 100 determines that there is a leakage abnormality in the second fuel system FL2 downstream of the second shutoff valve 22 (S210). Then, the process of S220 is executed.

[0069] On the other hand, if the determination in the processing of S120 described above is negative, the control device 100 determines whether the third pressure drop amount P3C is equal to or less than the third threshold value P3Cref (S500). The third pressure drop amount P3C and the third threshold value P3Cref in S500 are the same as the values ​​in the processing of S300 described above.

[0070] If it is determined in S500 that the third pressure drop amount P3C is equal to or less than the third threshold value P3Cref, the control device 100 determines that there is a leakage abnormality in the upstream first fuel system FL1H (S510), and then executes the process of S220.

[0071] On the other hand, if it is determined in S500 that the third pressure drop amount P3C exceeds the third threshold value P3Cref, the control device 100 determines that there is a leakage abnormality in the downstream first fuel system FL1L or the second shutoff valve 22 (S520). Then, the process of S220 is executed.

[0072] <Action and effect> The operation and effects of this embodiment will be described. (4-1) When the second shutoff valve 22 is closed and a leakage abnormality occurs in the second fuel system FL2 downstream of the second shutoff valve 22, no pressure drop occurs in the upstream first fuel system FL1H after the first fuel system FL1 is filled with gaseous fuel. On the other hand, if the second shutoff valve 22 is opened when a leakage abnormality occurs in the second fuel system FL2 downstream of the second shutoff valve 22, a pressure drop occurs in the second fuel system FL2. Therefore, when the second shutoff valve 22 is open, a pressure drop also occurs in the downstream first fuel system FL1L in accordance with the pressure drop in the second fuel system FL2. Therefore, in this embodiment, when the following conditions I and J are both satisfied, it is determined in the process of S210 that a leakage abnormality exists in the second fuel system FL2 downstream of the second shutoff valve 22.

[0073] Condition I: After the filling process of the first fuel system FL1 is completed, a positive determination is made in the process of S120, and therefore a pressure drop in the upstream first fuel system FL1H is not detected. Condition J: After the second shutoff valve 22 is opened, a negative determination is made in the processing of S530, and it is detected that a pressure drop has occurred in the downstream first fuel system FL1L.

[0074] Therefore, a leakage abnormality in the second fuel system FL2 downstream of the second shutoff valve 22 can be detected. (4-2) If there is a leakage abnormality in the first fuel system FL1 upstream of the pressure reducing valve 30, after the first fuel system FL1 is filled with gaseous fuel, a pressure drop occurs between the first shutoff valve 21 and the pressure reducing valve 30, but a pressure drop is unlikely to occur between the pressure reducing valve 30 and the second shutoff valve 22. Therefore, in this embodiment, if the following conditions K and L are both established, it is determined in the processing of S510 that there is a leakage abnormality in the upstream first fuel system FL1H.

[0075] Condition K: After the filling process of the first fuel system FL1 is completed, a negative determination is made in the process of S120, and a pressure drop is detected in the upstream first fuel system FL1H between the first shutoff valve 21 and the pressure reducing valve 30.

[0076] Condition L: Since the determination in the processing of S500 is affirmative, a pressure drop is not detected in the downstream first fuel system FL1L between the pressure reducing valve 30 and the second shutoff valve 22. Therefore, a leakage abnormality in the upstream first fuel system FL1H, which is the first fuel system FL1 upstream of the pressure reducing valve 30, can be detected.

[0077] (4-3) If there is a leakage abnormality in the first fuel system FL1 downstream of the pressure reducing valve 30 or in the second shutoff valve 22, after the first fuel system FL1 is filled with gaseous fuel, a pressure drop occurs in the upstream first fuel system FL1H between the first shutoff valve 21 and the pressure reducing valve 30. A pressure drop also occurs in the downstream first fuel system FL1L between the pressure reducing valve 30 and the second shutoff valve 22. Therefore, in this embodiment, if the following conditions K and M are both satisfied, it is determined in the processing of S520 that there is a leakage abnormality in the downstream first fuel system FL1L or the second shutoff valve 22.

[0078] Condition K: After the filling process of the first fuel system FL1 is completed, a negative determination is made in the process of S120, and a pressure drop is detected in the first fuel system FL1 between the first shutoff valve 21 and the pressure reducing valve 30.

[0079] Condition M: When a negative determination is made in the processing of S500, a pressure drop is detected in the downstream first fuel system FL1L between the pressure reducing valve 30 and the second shutoff valve 22. Therefore, a leakage abnormality in the downstream first fuel system FL1L, which is the first fuel system FL1 downstream of the pressure reducing valve 30, or in the second shutoff valve 22 can be detected.

[0080] (Fifth embodiment) Next, a fifth embodiment of an abnormality detection device for an internal combustion engine will be described with reference to FIG. <Process for Determining Fuel Leak Abnormality in the Present Embodiment> FIG. 6 shows the procedure of the determination process in this embodiment. The process shown in this FIG. 5 is implemented by the CPU 110 executing a program stored in the memory 120 of the control device 100. Note that the process shown in FIG. 5 starts to be executed when a stop request occurs for the internal combustion engine 10 during operation, such as when the ignition switch is turned off.

[0081] When starting this process, the control device 100 closes the first shut-off valve 21 by outputting a valve closing command to the first shut-off valve 21 that is open (S600). Next, the control device 100 determines whether the first pressure drop amount P1C is greater than or equal to the first threshold value P1Crefst (S610).

[0082] The first pressure drop amount P1C is a value obtained by subtracting the first pressure P1 at the time when the first shut-off valve 21 is closed in the process of S600 from the first pressure P1 at the time when a predetermined time has elapsed after the first shut-off valve 21 is closed in the same process. When there is no leakage abnormality in the first shut-off valve 21, the value of the first pressure drop amount P1C becomes a value greater than or equal to the above first threshold value P1Crefst. The first threshold value P1Crefst is a value obtained by multiplying the first pressure P1 when the first shut-off valve 21 is closed in the process of S600 by a predetermined coefficient K3. The coefficient K3 is a value within the range of "0 < K3 < 1" and is set in advance. Also, this coefficient K3 is set to a value larger than the above coefficient K1, and thus the first threshold value P1Crefst in this embodiment is a value larger than the above-described first threshold value P1Cref. This is because during engine operation, fuel injection from the fuel injection valve 15 is being performed, so the pressure drop in the fuel system after closing the first shut-off valve 21 is larger than the pressure drop when the engine operation is stopped.

[0083] [[ID=?]]In S610, when it is determined that the first pressure drop amount P1C is greater than or equal to the first threshold value P1Crefst, the control device 100 closes the second shut-off valve 22 by outputting a valve closing command to the second shut-off valve 22 that is open (S620).

[0084] It seems there is a small error in the original text where the line "In S610, when it is determined that the first pressure drop amount P1C is greater than or equal to the first threshold value P1Crefst, the control device 100 closes the second shut-off valve 22 by outputting a valve closing command to the second shut-off valve 22 that is open (S620)." has an incorrect line number "ID=?" in the original. It should probably be "ID=14" as it continues the sequence. I've translated it as best as possible with the given text.Next, the control device 100 determines whether or not the second pressure drop amount P2C is greater than or equal to the second threshold value P2Crefst (S630). The second pressure drop amount P2C is a value obtained by subtracting the second pressure P2 at the time when the second shut-off valve 22 is closed in the process of S620 from the second pressure P2 at the time when a predetermined time has elapsed after the second shut-off valve 22 is closed in the same process. When there is no leakage abnormality in the second shut-off valve 22, the value of the second pressure drop amount P2C becomes a value greater than or equal to the second threshold value P2Crefst. The second threshold value P2Crefst is a value obtained by multiplying the second pressure P2 at the time when the second shut-off valve 22 is closed in the process of S620 by a predetermined coefficient K4. The coefficient K4 is a value within the range of "0 < K4 < 1" and is set in advance. Also, the coefficient K4 is a value larger than the coefficient K2. Thus, the coefficient K4 is set to a value larger than the coefficient K2, and thereby the second threshold value P2Crefst of the present embodiment is a value larger than the above-described second threshold value P2Cref. This is because, as described above, during engine operation, fuel injection is performed from the fuel injection valve 15, so the pressure drop in the fuel system after the second shut-off valve 22 is closed is larger than the pressure drop when the engine operation is stopped.

[0085] If it is determined in S630 that the second pressure drop amount P2C is greater than or equal to the second threshold value P2Cref, the control device 100 executes engine stop (S600) and ends this process. If it is determined in S610 that the first pressure drop amount P1C is less than the first threshold value P1Crefst, the control device 100 determines that there is a leakage abnormality in the first shut-off valve 21 (S640). Then, the process of S660 is executed.

[0086] Also, if it is determined in S630 that the second pressure drop amount P2C is less than the second threshold value P2Crefst, the control device 100 determines that there is a leakage abnormality in the second shut-off valve 22 (S650). Then, the process of S660 is executed.

[0087] <Operation and Effect> The operation and effect of the present embodiment will be described. (5-1) When a valve closing abnormality occurs in which the first shutoff valve 21 cannot be closed, a leakage abnormality occurs in the first shutoff valve 21. Here, if there is no leakage abnormality in the first shutoff valve 21, when a valve close command is output to the first shutoff valve 21 during engine operation, fuel is injected from the fuel injection valve 15 while fuel supply to the first fuel system FL1 is stopped, causing a drop in pressure in the first fuel system FL1. On the other hand, when there is a leakage abnormality in the first shutoff valve 21, the first shutoff valve 21 does not close even when a valve close command is output to the first shutoff valve 21 during engine operation. Therefore, fuel supply to the first fuel system FL1 continues, and a drop in pressure in the first fuel system FL1 does not occur. Therefore, in this embodiment, when the following condition N is established, it is determined that there is a leakage abnormality in the first shutoff valve 21 in the processing of S640.

[0088] Condition N: After a valve close command is output to the first shutoff valve 21, a negative determination is made in S610, and therefore a pressure drop in the first fuel system FL1 is not detected. Therefore, a leakage abnormality in the first shutoff valve 21 can be detected.

[0089] (5-2) When a valve closing abnormality occurs in which the second shutoff valve 22 cannot be closed, a leakage abnormality occurs in the second shutoff valve 22. Here, if there is no leakage abnormality in the second shutoff valve 22, when a valve close command is output to the second shutoff valve 22 during engine operation, fuel is injected from the fuel injection valve 15 while fuel supply to the second fuel system FL2 is stopped, causing a pressure drop in the second fuel system FL2. On the other hand, when there is a leakage abnormality in the second shutoff valve 22, the second shutoff valve 22 does not close even when a valve close command is output to the second shutoff valve 22 during engine operation. Therefore, fuel supply to the second fuel system FL2 continues, and a pressure drop in the second fuel system FL2 does not occur. Therefore, in this embodiment, when the following condition O is established, it is determined that there is a leakage abnormality in the second shutoff valve 22 in the processing of S650.

[0090] Condition O: After a valve close command is output to the second shutoff valve 22, a negative determination is made in S630, and therefore a pressure drop in the second fuel system FL2 is not detected. Therefore, a leakage abnormality in the second shutoff valve 22 can be detected.

[0091] (5-3) In the present embodiment, when a request to stop the internal combustion engine 10 is made, a valve close command is output to the first shutoff valve 21 and the second shutoff valve 22. Therefore, compared to when a valve close command is output when a stop request is not made, the effect on engine operation caused by closing the first shutoff valve 21 and the second shutoff valve 22 can be reduced.

[0092] (Sixth embodiment) Next, a sixth embodiment of an abnormality detection device for an internal combustion engine will be described with reference to FIG. <Process for Determining Fuel Leak Abnormality in the Present Embodiment> As shown in Fig. 7, the determination process of this embodiment is a partial modification of the determination process described in the fifth embodiment. The determination process of this embodiment will be described below, focusing on these differences. Note that in Fig. 7, the same steps as those shown in Fig. 6 are assigned the same step numbers.

[0093] 7, the control device 100 executes the process of S700 instead of the process of S610 described above. In S700, the control device 100 determines whether the third pressure decrease amount P3C is equal to or greater than the third threshold value P3Crefst.

[0094] The third pressure drop amount P3C is a value obtained by subtracting the third pressure P3 at a predetermined time point after the first shutoff valve 21 is closed in the process of S600 from the third pressure P3 at that time. If no leakage abnormality occurs in the first shutoff valve 21, the value of the third pressure drop amount P3C is equal to or greater than the third threshold value P3Crefst.

[0095] The third threshold value P3Crefst is the value obtained by multiplying the third pressure P3 when the first shut-off valve 21 is closed in the process of S600 by a predetermined coefficient K5. The coefficient K5 is a value within the range of "0 < K5 < 1" and is set in advance. Also, this coefficient K5 is set to a value larger than the coefficient K3, and thus the third threshold value P3Crefst of the present embodiment is a value larger than the above-described third threshold value P3Cref. As described above, during engine operation, fuel injection from the fuel injection valve 15 is being performed, so the pressure drop in the fuel system after closing the first shut-off valve 21 is larger than the pressure drop when the engine operation is stopped.

[0096] And when an affirmative determination is made at 700, the control device 100 executes the processes after S620. On the other hand, when a negative determination is made at S700, the control device 100 executes the processes after S640.

[0097] <Actions and effects> The actions and effects of the present embodiment will be described. (6-1) The upstream first fuel system FL1H provided with the first pressure sensor 81 and the downstream first fuel system FL1L provided with the third pressure sensor 83 communicate with each other via the pressure reducing valve 30. Therefore, although the magnitudes of the first pressure P1 and the third pressure P3 are different, their change tendencies are the same. Therefore, the determination of whether or not a pressure drop has occurred in the first fuel system FL1 can be made based on either the first pressure P1 or the third pressure P3. Thus, in the present embodiment, the determination of whether or not a pressure drop has occurred in the first fuel system FL1 is made based on the third pressure P3. Therefore, in the present embodiment as well, the same actions and effects as those of the fifth embodiment can be obtained.

[0098] <Modification example> Note that each of the above embodiments can be implemented with the following modifications. Each of the above embodiments and the following modification examples can be implemented in combination with each other within a technically non-conflicting range.

[0099] In each embodiment, the magnitude relationship between the detection value of the first pressure sensor 81 and the first threshold value is the magnitude relationship between the first pressure drop amount P1C, which is the amount of change in the detection value of the first pressure sensor 81, and the first threshold value. Also, the magnitude relationship between the detection value of the second pressure sensor 82 and the second threshold value is the magnitude relationship between the second pressure drop amount P2C, which is the amount of change in the detection value of the second pressure sensor 82, and the second threshold value.

[0100] Alternatively, the magnitude relationship between the detection value of the first pressure sensor 81 and the first threshold value may be the magnitude relationship between the pressure value detected by the first pressure sensor 81 after the first fuel system FL1 is filled with gaseous fuel and the first threshold value. Similarly, the magnitude relationship between the detection value of the second pressure sensor 82 and the second threshold value may be the magnitude relationship between the pressure value detected by the second pressure sensor 82 after the second fuel system FL2 is filled with gaseous fuel and the second threshold value. Fig. 8 shows the determination process when this modified example is applied to, for example, the first embodiment.

[0101] 8, in this modified example, in the process of S120, it is determined whether the first pressure P1 is equal to or less than the first threshold value P1ref. The first pressure P1 at this time is the first pressure P1 when the first shutoff valve 21 is closed in the process of S110. Furthermore, the first threshold value P1ref is, for example, a value obtained by multiplying the first pressure P1 when the first shutoff valve 21 is closed in the process of S110 by a value of (1 - coefficient K1). The coefficient K1 is the same as the coefficient K1 described above.

[0102] Furthermore, in the process of S150, it is determined whether the second pressure P2 is equal to or less than the second threshold value P2ref. The second pressure P2 at this time is the second pressure P2 when the second shutoff valve 22 is closed in the process of S140. The second threshold value P2ref is, for example, a value obtained by multiplying the second pressure P2 when the second shutoff valve 22 is closed in the process of S140 by a value of (1-coefficient K2). The coefficient K2 is the same as the coefficient K2 described above. Note that the first pressure P1 and the second pressure P2 in this modified example are absolute pressures or gauge pressures.

[0103] Furthermore, the coefficient K2 is a larger value than the coefficient K1. Therefore, the value of (1 - coefficient K2) is smaller than the value of (1 - coefficient K1). Therefore, the ratio of the second threshold value P2ref to the second pressure P2 is smaller than the ratio of the first threshold value P1ref to the first pressure P1. Therefore, the second threshold value P2ref is set so that the range of pressure values ​​within which it is determined that there is no abnormality in the pressure drop is wider than the first threshold value P1ref. Therefore, it is possible to obtain the same actions and effects as those in (1-4) above.

[0104] The magnitude relationship between the detection value of the first pressure sensor 81 and the first threshold value may be the magnitude relationship between the rate of change of the detection value of the first pressure sensor 81 and the first threshold value. Similarly, the magnitude relationship between the detection value of the second pressure sensor 82 and the second threshold value may be the magnitude relationship between the rate of change of the detection value of the second pressure sensor 82 and the second threshold value.

[0105] Each threshold value described above is a value obtained by multiplying the pressure value by the coefficient K, but may be a predetermined fixed value. In the fifth and sixth embodiments, only the leakage abnormality of the first shutoff valve 21 or only the leakage abnormality of the second shutoff valve 22 may be determined.

[0106] In the first and fifth embodiments, the third pressure sensor 83 may be omitted. The gaseous fuel is hydrogen gas, but other gaseous fuels, such as compressed natural gas, may also be used. The control device 100 includes a CPU 110 and a memory 120 and executes software processing. However, this is merely an example. The control device 100 may also include a dedicated hardware circuit (e.g., an ASIC) that processes at least part of the software processing executed in the above embodiment. That is, the control device 100 may have any of the following configurations (a) to (c): (a) a processing device that executes all of the above processing according to a program and a program storage device such as a memory that stores the program; (b) a processing device and program storage device that executes part of the above processing according to a program and a dedicated hardware circuit that executes the remaining processing; or (c) a dedicated hardware circuit that executes all of the above processing. Here, there may be multiple software circuits and dedicated hardware circuits that include a processing device and a program storage device. That is, the above processing may be executed by a processing circuit that includes at least one software circuit and one or more dedicated hardware circuits. The program storage device, i.e., computer-readable medium, includes any available medium that can be accessed by a general-purpose or dedicated computer.

[0107] <Related technical ideas> The technical ideas that can be understood from the above-described embodiments and modifications will be described below. (Appendix 1) an abnormality detection device for an internal combustion engine equipped with a fuel supply device including: a tank for storing gaseous fuel; a fuel injection valve for supplying fuel to a cylinder; a fuel passage for supplying the gaseous fuel in the tank to the fuel injection valve; a first shutoff valve provided in the fuel passage downstream of the tank; a pressure reducing valve provided in the fuel passage downstream of the first shutoff valve; a second shutoff valve provided in the fuel passage downstream of the pressure reducing valve; a first pressure sensor provided in a first fuel system which is a fuel system between the first shutoff valve and the second shutoff valve; and a second pressure sensor provided in a second fuel system which is a fuel system between the second shutoff valve and the fuel injection valve, An abnormality detection device for an internal combustion engine that performs a determination process to determine whether there is a leak abnormality in the first fuel system or the second fuel system based on the magnitude relationship between the detection value of the first pressure sensor when the first fuel system is filled with gaseous fuel and a predetermined first threshold value, and the magnitude relationship between the detection value of the second pressure sensor when the second fuel system is filled with gaseous fuel and a predetermined second threshold value.

[0108] (Appendix 2) The abnormality detection device for an internal combustion engine described in Appendix 1, wherein the magnitude relationship between the detection value of the first pressure sensor and the first threshold value is the magnitude relationship between the amount of change in the detection value of the first pressure sensor and the first threshold value, and the magnitude relationship between the detection value of the second pressure sensor and the second threshold value is the magnitude relationship between the amount of change in the detection value of the second pressure sensor and the second threshold value, and the second threshold value is set so that the range in which it is determined that there is no abnormality in the pressure drop for the amount of change is wider than the first threshold value.

[0109] (Appendix 3) An abnormality detection device for an internal combustion engine as described in Appendix 1, wherein the magnitude relationship between the detection value of the first pressure sensor and the first threshold value is the magnitude relationship between the pressure value detected by the first pressure sensor after gas fuel is filled into the first fuel system and the first threshold value, and the magnitude relationship between the detection value of the second pressure sensor and the second threshold value is the magnitude relationship between the pressure value detected by the second pressure sensor and the second threshold value, and the second threshold value is set so that the range in which it is determined that there is no abnormality in the pressure drop for the pressure value is wider than the first threshold value.

[0110] (Appendix 4) the first shutoff valve and the second shutoff valve are maintained in a closed state while the internal combustion engine is stopped, When a request to start the internal combustion engine is made, a valve open command is output to the first shutoff valve, and then a valve close command is output to execute a filling process of filling the first fuel system with gas fuel; and The abnormality detection device for an internal combustion engine according to any one of Supplementary Note 1 to Supplementary Note 3, wherein the determination process executes a process of determining that there is a leakage abnormality in the second shut-off valve if a pressure drop in the first fuel system is detected based on the magnitude relationship between the detection value of the first pressure sensor after the filling process is completed and the first threshold value, and if an increase in the pressure detected by the second pressure sensor is detected when the valve open command is output to the first shut-off valve.

[0111] (Appendix 5) The abnormality detection device for an internal combustion engine described in Appendix 4, wherein the determination process executes a process to determine that there is a leakage abnormality in the first fuel system upstream of the second shutoff valve when a pressure drop in the first fuel system is detected based on the magnitude relationship between the detection value of the first pressure sensor after the filling process is completed and the first threshold value, and when it is detected that the pressure detected by the second pressure sensor has not increased when the open valve command is output to the first shutoff valve.

[0112] (Appendix 6) when a pressure drop in the first fuel system based on a magnitude relationship between a detection value of the first pressure sensor and the first threshold value after the filling process is completed is not detected by the determination process, a filling process is executed to fill the second fuel system with gaseous fuel by outputting a valve open command to the second shutoff valve and then outputting a valve close command to the second shutoff valve; The abnormality detection device for an internal combustion engine described in Appendix 4 or Appendix 5, wherein the determination process executes a process to determine that there is a leakage abnormality in the second fuel system downstream of the second shut-off valve when a pressure drop in the second fuel system is detected based on the magnitude relationship between the detection value of the second pressure sensor and the second threshold value after the filling process of filling the second fuel system with gaseous fuel is completed.

[0113] (Appendix 7) the first shutoff valve and the second shutoff valve are maintained in an open state while the internal combustion engine is in operation, When a request to stop the internal combustion engine is made, a process is executed to output a valve close command to the first shutoff valve, The abnormality detection device for an internal combustion engine according to any one of Supplementary Note 1 to Supplementary Note 6, wherein the determination process executes a process of determining that there is a leakage abnormality in the first shutoff valve when a pressure drop in the first fuel system is not detected based on a magnitude relationship between the detection value of the first pressure sensor after outputting a valve close command to the first shutoff valve and the first threshold value.

[0114] (Appendix 8) When a pressure drop in the first fuel system is detected by the determination process based on the magnitude relationship between the detection value of the first pressure sensor after outputting a valve close command to the first shutoff valve and the first threshold value, a process is executed to output a valve close command to the second shutoff valve, The abnormality detection device for an internal combustion engine described in Appendix 7, wherein the determination process executes a process to determine that there is a leakage abnormality in the second shutoff valve if a pressure drop in the second fuel system is not detected based on the magnitude relationship between the detection value of the second pressure sensor after the valve close command is output to the second shutoff valve and the second threshold value.

[0115] (Appendix 9) 9. The abnormality detection device for an internal combustion engine according to claim 1, wherein the first pressure sensor is provided in the fuel passage between the first shutoff valve and the pressure reducing valve.

[0116] (Appendix 10) 9. The abnormality detection device for an internal combustion engine according to claim 1, wherein the first pressure sensor is provided in the fuel passage between the pressure reducing valve and the second shutoff valve.

[0117] (Appendix 11) the first shutoff valve and the second shutoff valve are maintained in a closed state while the internal combustion engine is stopped, the first pressure sensor includes an upstream pressure sensor provided in the fuel passage between the first shutoff valve and the pressure reducing valve, and a downstream pressure sensor provided in the fuel passage between the pressure reducing valve and the second shutoff valve, When a request to start the internal combustion engine is made, a valve open command is output to the first shutoff valve, and then a valve close command is output to execute a filling process of filling the first fuel system with gas fuel; and The abnormality detection device for an internal combustion engine according to any one of Supplementary Note 1 to Supplementary Note 8, wherein the determination process executes a process of determining that there is a leakage abnormality in the first fuel system upstream of the pressure reducing valve when a pressure drop between the first shut-off valve and the pressure reducing valve in the first fuel system is detected based on the magnitude relationship between the detection value of the upstream pressure sensor and the first threshold value after the filling process is completed, and when a pressure drop between the pressure reducing valve and the second shut-off valve in the first fuel system is not detected based on the magnitude relationship between the detection value of the downstream pressure sensor and a predetermined third threshold value.

[0118] (Appendix 12) The abnormality detection device for an internal combustion engine described in Appendix 11, wherein the determination process detects a pressure drop between the first shut-off valve and the pressure reducing valve in the first fuel system based on the magnitude relationship between the detection value of the upstream pressure sensor and the first threshold value after the filling process is completed, and detects a pressure drop between the pressure reducing valve and the second shut-off valve in the first fuel system based on the magnitude relationship between the detection value of the downstream pressure sensor and a predetermined third threshold value, and if the pressure detected by the second pressure sensor does not increase when the valve open command is output to the first shut-off valve, a process is executed to determine that a leakage abnormality exists in the first fuel system downstream of the pressure reducing valve. [Explanation of symbols]

[0119] 10...Internal combustion engine 15...Fuel injection valve 20...Tank 21...First shutoff valve 22...Second shutoff valve 30...Reducing valve 40…Fuel piping 60...Delivery pipe 81...First pressure sensor 82...Second pressure sensor 83...Third pressure sensor 100...Control device 200… Fuel supply device

Claims

1. an abnormality detection device for an internal combustion engine equipped with a fuel supply device including: a tank for storing gaseous fuel; a fuel injection valve for supplying fuel to a cylinder; a fuel passage for supplying the gaseous fuel in the tank to the fuel injection valve; a first shutoff valve provided in the fuel passage downstream of the tank; a pressure reducing valve provided in the fuel passage downstream of the first shutoff valve; a second shutoff valve provided in the fuel passage downstream of the pressure reducing valve; a first pressure sensor provided in a first fuel system which is a fuel system between the first shutoff valve and the second shutoff valve; and a second pressure sensor provided in a second fuel system which is a fuel system between the second shutoff valve and the fuel injection valve, A determination process is performed to determine whether there is a leakage abnormality in the first fuel system or the second fuel system based on the magnitude relationship between the detection value of the first pressure sensor and a predetermined first threshold value when the first fuel system is filled with gaseous fuel, and the magnitude relationship between the detection value of the second pressure sensor and a predetermined second threshold value when the second fuel system is filled with gaseous fuel. An abnormality detection device for internal combustion engines.

2. The magnitude relationship between the detection value of the first pressure sensor and the first threshold value is the magnitude relationship between the amount of change in the detection value of the first pressure sensor and the first threshold value, and the magnitude relationship between the detection value of the second pressure sensor and the second threshold value is the magnitude relationship between the amount of change in the detection value of the second pressure sensor and the second threshold value, and the second threshold value is set so that the range in which it is determined that there is no abnormality in the amount of change is wider than the first threshold value. The abnormality detection device for an internal combustion engine according to claim 1.

3. The magnitude relationship between the detection value of the first pressure sensor and the first threshold value is the magnitude relationship between the pressure value detected by the first pressure sensor after the first fuel system is filled with gaseous fuel and the first threshold value, and the magnitude relationship between the detection value of the second pressure sensor and the second threshold value is the magnitude relationship between the pressure value detected by the second pressure sensor and the second threshold value, and the second threshold value is set so that the range in which it is determined that there is no abnormality in the pressure value is wider than the first threshold value. The abnormality detection device for an internal combustion engine according to claim 1.

4. the first shutoff valve and the second shutoff valve are maintained in a closed state while the internal combustion engine is stopped, When a start request for the internal combustion engine is made, a valve open command is output to the first shutoff valve, and then a valve close command is output to execute a filling process of filling the first fuel system with gas fuel; and The determination process executes a process of determining that a leakage abnormality exists in the second shutoff valve when a pressure drop in the first fuel system is detected based on a magnitude relationship between a detection value of the first pressure sensor after the filling process is completed and the first threshold value, and when an increase in the pressure detected by the second pressure sensor is detected when the valve open command is output to the first shutoff valve. The abnormality detection device for an internal combustion engine according to claim 1.

5. the first shutoff valve and the second shutoff valve are maintained in a closed state while the internal combustion engine is stopped, When a start request for the internal combustion engine is made, a valve open command is output to the first shutoff valve, and then a valve close command is output to execute a filling process of filling the first fuel system with gas fuel; and The determination process executes a process of determining that there is a leakage abnormality in the first fuel system upstream of the second shutoff valve when a pressure drop in the first fuel system is detected based on a magnitude relationship between the detection value of the first pressure sensor after the filling process is completed and the first threshold value, and when it is detected that the pressure detected by the second pressure sensor has not increased when the valve open command is output to the first shutoff valve. The abnormality detection device for an internal combustion engine according to claim 1.

6. the first shutoff valve and the second shutoff valve are maintained in a closed state while the internal combustion engine is stopped, When a start request for the internal combustion engine is made, a valve open command is output to the first shutoff valve, and then a valve close command is output to execute a filling process of filling the first fuel system with gas fuel; and when a pressure drop in the first fuel system based on the magnitude relationship between the detection value of the first pressure sensor and the first threshold value after the filling process is completed is not detected by the determination process, a filling process is executed to fill the second fuel system with gaseous fuel by outputting a valve open command to the second shutoff valve and then outputting a valve close command to the second shutoff valve; The determination process executes a process of determining that a leakage abnormality exists in the second fuel system downstream of the second shutoff valve when a pressure drop in the second fuel system is detected based on a magnitude relationship between a detection value of the second pressure sensor and the second threshold value after the filling process of filling the second fuel system with gaseous fuel is completed. The abnormality detection device for an internal combustion engine according to claim 1.

7. the first shutoff valve and the second shutoff valve are maintained in a closed state while the internal combustion engine is stopped, the first pressure sensor includes an upstream pressure sensor provided in the fuel passage between the first shutoff valve and the pressure reducing valve, and a downstream pressure sensor provided in the fuel passage between the pressure reducing valve and the second shutoff valve, When a start request for the internal combustion engine is made, a valve open command is output to the first shutoff valve, and then a valve close command is output to execute a filling process of filling the first fuel system with gas fuel; and The determination process executes a process of determining that there is a leakage abnormality in the first fuel system upstream of the pressure reducing valve when a pressure drop between the first shutoff valve and the pressure reducing valve in the first fuel system is detected based on the magnitude relationship between the detection value of the upstream pressure sensor and the first threshold value after the filling process is completed, and when a pressure drop between the pressure reducing valve and the second shutoff valve in the first fuel system is not detected based on the magnitude relationship between the detection value of the downstream pressure sensor and a predetermined third threshold value. The abnormality detection device for an internal combustion engine according to claim 1.

8. the first shutoff valve and the second shutoff valve are maintained in a closed state while the internal combustion engine is stopped, the first pressure sensor includes an upstream pressure sensor provided in the fuel passage between the first shutoff valve and the pressure reducing valve, and a downstream pressure sensor provided in the fuel passage between the pressure reducing valve and the second shutoff valve, When a start request for the internal combustion engine is made, a valve open command is output to the first shutoff valve, and then a valve close command is output to execute a filling process of filling the first fuel system with gas fuel; and The determination process executes a process of determining that a leakage abnormality exists in the first fuel system downstream of the pressure reducing valve when a pressure drop between the first shutoff valve and the pressure reducing valve in the first fuel system is detected based on a magnitude relationship between a detection value of the upstream pressure sensor and the first threshold value after the filling process is completed, and a pressure drop between the pressure reducing valve and the second shutoff valve in the first fuel system is detected based on a magnitude relationship between a detection value of the downstream pressure sensor and a predetermined third threshold value, and when the pressure detected by the second pressure sensor does not increase when the valve open command is output to the first shutoff valve. The abnormality detection device for an internal combustion engine according to claim 1.

9. the first shutoff valve and the second shutoff valve are maintained in an open state during operation of the internal combustion engine, When a request to stop the internal combustion engine is made, a process is executed to output a valve close command to the first shutoff valve; The determination process executes a process of determining that a leakage abnormality exists in the first shutoff valve when a pressure drop in the first fuel system is not detected based on a magnitude relationship between a detection value of the first pressure sensor after a valve close command is output to the first shutoff valve and the first threshold value. The abnormality detection device for an internal combustion engine according to claim 1.

10. the first shutoff valve and the second shutoff valve are maintained in an open state during operation of the internal combustion engine, When a request to stop the internal combustion engine is made, a process is executed to output a valve close command to the second shutoff valve, and The determination process executes a process of determining that a leakage abnormality exists in the second shutoff valve when a pressure drop in the second fuel system is not detected based on a magnitude relationship between a detection value of the second pressure sensor after a valve close command is output to the second shutoff valve and the second threshold value. The abnormality detection device for an internal combustion engine according to claim 1.

11. The first pressure sensor is provided in the fuel passage between the first shutoff valve and the pressure reducing valve. The abnormality detection device for an internal combustion engine according to claim 1.

12. The first pressure sensor is provided in the fuel passage between the pressure reducing valve and the second shutoff valve. The abnormality detection device for an internal combustion engine according to claim 1.

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