Fault determination device and fault determination method

Abstract

The present invention provides a fault detection device that can quickly bring a vehicle into a state where it can be operated according to user input when a request to operate the hydrogen engine is received before the fault detection routine is completed. [Solution] The fuel supply system 10 includes a hydrogen engine 15, a fuel tank 11, hydrogen piping 12, and a first shut-off valve 21 and a second shut-off valve 22, which are shut-off valves for shutting off hydrogen gas. When an operation is made to stop the hydrogen engine 15, the fault detection device 40 closes the shut-off valves and, while continuing to operate the hydrogen engine 15, observes the rate of decrease in hydrogen gas pressure downstream of the shut-off valves. If the rate of decrease is slow, the fault detection device 40 executes a fault detection routine that determines that the shut-off valves have not been closed properly. When an operation is made to start the hydrogen engine 15 while the fault detection routine is being executed, the fault detection device 40 opens the shut-off valves while continuing to operate the hydrogen engine 15 and stops the fault detection routine.

Description

Technical Field

[0001] This invention relates to a failure determination device and a failure determination method.

Background Art

[0002] Patent Document 1 describes a failure determination device in a fuel supply system. The fuel supply system includes a hydrogen engine that uses hydrogen gas as fuel and a fuel tank that stores the hydrogen gas used by the hydrogen engine. The hydrogen gas stored in the fuel tank is sent to the hydrogen engine through a hydrogen pipe. The fuel supply system includes a shut-off valve on the hydrogen pipe. The shut-off valve blocks the hydrogen gas sent from the fuel tank to the hydrogen engine in the hydrogen pipe.

[0003] The failure determination device described in Patent Document 1 executes a failure determination routine. In the failure determination routine, the failure determination device determines whether the shut-off valve is faulty based on the change in the pressure of the hydrogen gas in the portion between the shut-off valve and the hydrogen engine in a state where the shut-off valve is closed and the hydrogen engine is consuming hydrogen gas. Here, the state where the shut-off valve is faulty means that the shut-off valve is not properly closed and the hydrogen gas is not blocked in the hydrogen pipe.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The above failure determination device continues the state where the shut-off valve is closed until the failure determination routine is completed. Therefore, the supply of hydrogen gas from the fuel tank is not performed until the failure determination routine is completed.

Means for Solving the Problems

[0006] A fault detection device for solving the above problems is applied to a fuel supply system. The fuel supply system includes a hydrogen engine that uses hydrogen gas as fuel, a fuel tank for storing the hydrogen gas, hydrogen piping for leading the hydrogen gas from the fuel tank to the hydrogen engine, and a shut-off valve provided in the middle of the hydrogen piping for shutting off the supply of hydrogen gas from the fuel tank to the hydrogen engine. This fault detection device controls the shut-off valve and the hydrogen engine to determine whether or not there is a fault in the shut-off valve. When a user of a vehicle equipped with the fuel supply system requests that the hydrogen engine be stopped, this fault detection device closes the shut-off valve and, while continuing to operate the hydrogen engine, observes the rate of pressure drop of the hydrogen gas downstream of the shut-off valve, and executes a fault detection routine that determines that the shut-off valve is not properly closed if the rate of pressure drop is slow. When the user requests that the hydrogen engine be started while the fault detection routine is being executed, this fault detection device opens the shut-off valve while continuing to operate the hydrogen engine and stops the fault detection routine.

[0007] A fault detection method for solving the above problems is applied to a fuel supply system. The fuel supply system includes a hydrogen engine that uses hydrogen gas as fuel, a fuel tank for storing the hydrogen gas, hydrogen piping for leading the hydrogen gas from the fuel tank to the hydrogen engine, and a shut-off valve provided in the middle of the hydrogen piping for shutting off the supply of hydrogen gas from the fuel tank to the hydrogen engine. This fault detection method controls the shut-off valve and the hydrogen engine to determine whether or not there is a fault in the shut-off valve. This fault detection method includes the step of starting a fault detection routine in which, when a user of a vehicle equipped with the fuel supply system requests that the hydrogen engine be stopped, the fault detection device closes the shut-off valve and, while continuing to operate the hydrogen engine, observes the rate of pressure drop of the hydrogen gas downstream of the shut-off valve, and if the rate of drop is slow, determines that the shut-off valve has not been closed properly. This fault detection method includes the step of the fault detection device determining that a user has requested that the hydrogen engine be operated. This fault detection method includes the step, when the user requests the operation of the hydrogen engine while the fault detection routine is being executed, the fault detection device opens the shut-off valve and terminates the fault detection routine while continuing to operate the hydrogen engine. [Effects of the Invention]

[0008] The above-described fault detection device and fault detection method can quickly resume fuel supply and bring the vehicle into a state where it can be operated according to the user's input if the user requests the hydrogen engine to start before the fault detection routine is completed. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing the configuration of a fuel supply system equipped with a fault detection device according to one embodiment. [Figure 2] Figure 2 is a flowchart showing the sequence of processes in the first fault detection routine executed by the fault detection device. [Figure 3] Figure 3 is a flowchart showing the sequence of processes in the second fault detection routine executed by the fault detection device. [Modes for carrying out the invention]

[0010] Below, one embodiment of the fault detection device will be described with reference to Figures 1 to 3. <Configuration of fuel supply system 10> The fuel supply system 10 is mounted on the vehicle. As shown in Figure 1, the fuel supply system 10 comprises a fuel tank 11, hydrogen piping 12, and a hydrogen engine 15.

[0011] The fuel tank 11 stores hydrogen gas supplied from an external source. As shown in Figure 1, the fuel tank 11 is connected to the hydrogen engine 15 through hydrogen piping 12. Hydrogen piping 12 guides hydrogen gas from the fuel tank 11 to the hydrogen engine 15. The hydrogen gas guided to the hydrogen engine 15 is supplied into the cylinders of the hydrogen engine 15 from the injectors of the hydrogen engine 15.

[0012] The hydrogen engine 15 uses hydrogen gas as fuel. The hydrogen engine 15 outputs driving force to the vehicle equipped with the fuel supply system 10 by burning hydrogen gas in its cylinders. As shown in Figure 1, a regulator 13, multiple shut-off valves, and multiple pressure sensors are installed along the hydrogen piping 12.

[0013] The regulator 13 adjusts the pressure of the hydrogen gas supplied from the fuel tank 11 to the hydrogen engine 15 to a level usable by the hydrogen engine 15 by reducing the pressure of the hydrogen gas. Figure 1 shows the high-pressure section HS and the low-pressure section LS in the hydrogen piping 12. The high-pressure section HS is the part of the hydrogen piping 12 through which the hydrogen gas passes before passing through the regulator 13. The low-pressure section LS is the part of the hydrogen piping 12 through which the hydrogen gas passes after passing through the regulator 13.

[0014] As shown in FIG. 1, the fuel supply system 10 includes, as a plurality of shut-off valves, a first shut-off valve 21 and a second shut-off valve 22. The shut-off valves shut off the supply of hydrogen gas from the fuel tank 11 to the hydrogen engine 15.

[0015] As shown in FIG. 1, the first shut-off valve 21 is installed in a portion of the hydrogen pipe 12 between the fuel tank 11 and the regulator 13. When the first shut-off valve 21 is closed, the high-pressure section HS is shut off.

[0016] As shown in FIG. 1, the second shut-off valve 22 is installed in a portion of the hydrogen pipe 12 between the regulator 13 and the hydrogen engine 15. When the second shut-off valve 22 is closed, the low-pressure section LS is shut off.

[0017] As shown in FIG. 1, the fuel supply system 10 includes a first pressure sensor 31 and a second pressure sensor 32 as a plurality of pressure sensors. As shown in FIG. 1, the first pressure sensor 31 is installed in a portion of the high-pressure section HS downstream of the first shut-off valve 21. As shown in FIG. 1, the second pressure sensor 32 is installed in a portion of the low-pressure section LS downstream of the second shut-off valve 22.

[0018] As shown in FIG. 1, the fuel supply system 10 includes a failure determination device 40. The failure determination device 40 is applied to the fuel supply system 10. The failure determination device 40 is, for example, an electronic control device that controls the injection of hydrogen gas by an injector of the hydrogen engine 15.

[0019] As shown in FIG. 1, the failure determination device 40 is communicably connected to the hydrogen engine 15. The failure determination device 40 controls the operation of the hydrogen engine 15. As shown in FIG. 1, the failure determination device 40 is communicably connected to the first shut-off valve 21 and the second shut-off valve 22. The failure determination device 40 controls the opening and closing of the first shut-off valve 21 and the second shut-off valve 22.

[0020] As shown in FIG. 1, the failure determination device 40 is communicably connected to the first pressure sensor 31 and the second pressure sensor 32. The failure determination device 40 can acquire the values measured by the first pressure sensor 31 and the second pressure sensor 32.

[0021] The failure determination device 40 executes a failure determination routine. The failure determination routine is a series of processes performed to determine whether there is a failure in the shut-off valve by the failure determination device 40. The failure of the shut-off valve here refers to a state where, despite the failure determination device 40 instructing the shut-off valve to close, the shut-off valve is not properly closed. For example, when a foreign object is caught between the shut-off valves, the above failure occurs.

[0022] <Mode of processing in the first failure determination routine DF1> FIGS. 2 and 3 show the flow of a series of processes executed when the failure determination device 40 performs a failure determination routine. The series of processes shown in FIGS. 2 and 3 are executed while the vehicle is in operation. In the situation where the vehicle is operating, the failure determination device 40 operates the hydrogen engine 15 while opening the first shut-off valve 21 and the second shut-off valve 22.

[0023] In the process of step S11, the failure determination device 40 determines whether the user of the vehicle has performed an operation (IG-OFF) to turn off the ignition switch. The operation of turning off the ignition switch is an operation for the user to request the stop of the hydrogen engine 15.

[0024] [[ID=IS]]If the failure determination device 40 determines in the process of step S11 that the user has not performed an operation to turn off the ignition switch (step S11: NO), the process of step S11 is performed again. Thus, the failure determination device 40 repeats the process of step S11 until the user turns off the ignition switch. If the failure determination device 40 determines in the process of step S11 that the user has performed an operation to turn off the ignition switch (step S1l: YES), the process proceeds to step S12.

[0025] The fault detection device 40 starts the fault detection routine when it determines that the user has turned off the ignition switch. The fault detection device 40 performs the fault detection routine while the hydrogen engine 15 continues to operate after the ignition switch has been turned off.

[0026] The process from steps S12 to S18 shown in Figure 2 constitutes the first fault determination routine DF1, which targets the first shut-off valve 21. The first fault determination routine DF1 is a fault determination routine that determines whether or not there is a fault in the first shut-off valve 21.

[0027] In step S12, the fault detection device 40 closes the first shut-off valve 21. At this time, the fault detection device 40 maintains the second shut-off valve 22 in an open state. In the next step, S13, the fault detection device 40 obtains pressure P1. Pressure P1 is the pressure of the hydrogen gas downstream of the first shut-off valve 21 immediately after the first shut-off valve 21 is closed. The fault detection device 40 obtains pressure P1 from the first pressure sensor 31.

[0028] In the next step, S14, the fault detection device 40 determines whether a predetermined time t1 has elapsed since the first shut-off valve 21 was closed. The predetermined time t1 is set in advance. If the fault detection device 40 determines that a predetermined time t1 has not elapsed in the process of step S14 (step S14: NO), it proceeds to step S19.

[0029] In step S19, the fault detection device 40 determines whether the user has performed the operation of turning on the ignition switch (IG-ON). Turning on the ignition switch is an operation in which the user requests the operation of the hydrogen engine 15. Thus, in step S19, the fault detection device 40 determines whether the user has performed the operation of requesting the operation of the hydrogen engine 15 while the first fault detection routine DF1 is being executed.

[0030] If the fault detection device 40 determines in step S19 that the user has not turned on the ignition switch (step S19: NO), it will execute the process in step S14 again.

[0031] If the fault detection device 40 determines that a predetermined time t1 has elapsed in step S14 (step S14: YES), it proceeds to step S15. In step S15, the fault detection device 40 obtains pressure P2. Pressure P2 is the pressure of hydrogen gas downstream of the first shut-off valve 21 when a predetermined time t1 has elapsed after the first shut-off valve 21 is closed. The fault detection device 40 obtains pressure P2 from the first pressure sensor 31.

[0032] In the next step, S16, the fault detection device 40 determines whether the difference between pressure P1 and pressure P2 is greater than or equal to the threshold N1. In the first fault detection routine DF1, the hydrogen gas flowing through the hydrogen piping 12 downstream of the first shut-off valve 21 is gradually consumed by the hydrogen engine 15 over a predetermined time t1. If the first shut-off valve 21 is not properly closed, the rate at which the hydrogen gas pressure downstream of the first shut-off valve 21 decreases is slower compared to when the first shut-off valve 21 is properly closed.

[0033] During steps S13 to S16, the fault detection device 40 observes the rate at which the hydrogen gas pressure decreases downstream of the first shut-off valve 21. The difference between pressure P1 and pressure P2 reflects the rate at which the hydrogen gas pressure decreases downstream of the first shut-off valve 21.

[0034] The threshold N1 is predetermined by the manufacturer of the fault detection device 40. The manufacturer of the fault detection device 40 measures, for example, the difference between pressure P1 and pressure P2 when the first shut-off valve 21 is properly closed. The manufacturer of the fault detection device 40 then sets the threshold N1 based on the measured value.

[0035] If the fault detection device 40 determines in step S16 that the difference between pressure P1 and pressure P2 is greater than or equal to the threshold N1 (step S16: YES), it proceeds to step S17. In step S17, the fault detection device 40 determines that the first shut-off valve 21 is not faulty.

[0036] If the fault detection device 40 determines in step S16 that the difference between pressure P1 and pressure P2 is less than the threshold N1 (step S16: NO), it proceeds to step S18. The difference between pressure P1 and pressure P2 being less than the threshold N1 indicates that the rate of pressure drop of hydrogen gas downstream of the first shut-off valve 21 is slower than when the first shut-off valve 21 is normally closed. In step S18, the fault detection device 40 determines that the first shut-off valve 21 is faulty. Thus, the first fault detection routine DF1 is completed when the determination result is output in step S17 or step S18.

[0037] <Processing method when the first fault detection routine DF1 is terminated> If the fault detection device 40 determines in step S19 that the user has turned on the ignition switch (step S19: YES), it executes the process in step S20.

[0038] In step S20, the fault detection device 40 opens the first shut-off valve 21. When the fault detection device 40 opens the first shut-off valve 21 in step S20, all shut-off valves installed in the fuel supply system 10 become open. As a result, hydrogen gas is supplied from the fuel tank 11 to the operating hydrogen engine 15.

[0039] As shown in Figure 3, after executing the process in step S20, the fault detection device 40 terminates the series of processes shown in Figures 2 and 3. In this case, the fault detection device 40 terminates the series of processes shown in Figures 2 and 3 without determining whether or not the first shut-off valve 21 is faulty. In other words, if the ignition switch is turned on while the first fault detection routine DF1 is being executed, the fault detection device 40 cancels the first fault detection routine DF1.

[0040] <Processing method in the second fault detection routine DF2> As shown in Figure 3, once the first fault determination routine DF1 is completed, the fault determination device 40 proceeds to step S21 and starts the second fault determination routine DF2. The second fault determination routine DF2 is a fault determination routine that determines whether or not there is a fault in the second shut-off valve 22.

[0041] The process from steps S21 to S27 shown in Figure 3 constitutes the second fault determination routine DF2. If the first fault detection routine DF1 is completed without being aborted, the fault detection device 40 executes the second fault detection routine DF2. In this way, the fault detection device 40 executes the fault detection routines while sequentially changing the target shut-off valve from upstream.

[0042] In step S21, the fault detection device 40 closes the second shut-off valve 22. In the next step, S22, the fault detection device 40 obtains pressure P3. Pressure P3 is the pressure of the hydrogen gas downstream of the second shut-off valve 22 immediately after the second shut-off valve 22 is closed. The fault detection device 40 obtains pressure P3 from the second pressure sensor 32.

[0043] In the next step, S23, the fault detection device 40 determines whether a predetermined time t2 has elapsed since the second shut-off valve 22 was closed. The predetermined time t2 is set in advance. If the fault detection device 40 determines that a predetermined time t2 has not elapsed in step S23 (step S23: NO), it proceeds to step S29. In step S29, the fault detection device 40 determines whether or not the user has turned on the ignition switch. As a result, in step S29, the fault detection device 40 determines whether or not the user has requested the operation of the hydrogen engine 15 during the execution of the second fault detection routine DF2.

[0044] If the fault detection device 40 determines in step S29 that the user has not turned on the ignition switch (step S29: NO), it will execute the process in step S23 again.

[0045] If the fault detection device 40 determines that a predetermined time t2 has elapsed in step S23 (step S23: YES), it proceeds to step S24. In step S24, the fault detection device 40 obtains the pressure P4. Pressure P4 is the pressure of the hydrogen gas downstream of the second shut-off valve 22 when a predetermined time t2 has elapsed after the second shut-off valve 22 has been closed. The fault detection device 40 obtains the pressure P4 from the second pressure sensor 32.

[0046] In step S25, the fault detection device 40 determines whether the difference between pressure P3 and pressure P4 is greater than or equal to the threshold N2. In the second fault detection routine DF2, the hydrogen gas flowing through the hydrogen piping 12 downstream of the second shut-off valve 22 is gradually consumed by the hydrogen engine 15 over a predetermined time t2. If the second shut-off valve 22 is not properly closed, the rate at which the hydrogen gas pressure downstream of the second shut-off valve 22 decreases is slower compared to when the second shut-off valve 22 is properly closed.

[0047] The difference between pressure P3 and pressure P4 reflects the rate at which the hydrogen gas pressure decreases downstream of the second shut-off valve 22. During steps S22 to S25, the fault detection device 40 observes the rate at which the hydrogen gas pressure decreases downstream of the second shut-off valve 22.

[0048] The threshold N2, like the threshold N1, is predetermined by the manufacturer of the fault detection device 40. The manufacturer of the fault detection device 40 measures, for example, the difference between pressure P3 and pressure P4 when the second shut-off valve 22 is properly closed. The manufacturer of the fault detection device 40 then sets the threshold N2 based on the measured value.

[0049] In step S25, if the fault detection device 40 determines that the difference between pressure P3 and pressure P4 is greater than or equal to the threshold N2 (step S25: YES), it proceeds to step S26. In step S26, the fault detection device 40 determines that the second shut-off valve 22 is not faulty.

[0050] If the fault detection device 40 determines in step S25 that the difference between pressure P3 and pressure P4 is less than the threshold N2 (step S25: NO), it proceeds to step S27. The difference between pressure P3 and pressure P4 being less than the threshold N2 indicates that the rate of pressure drop of hydrogen gas downstream of the second shut-off valve 22 is slower than when the second shut-off valve 22 is normally closed. In step S27, the fault detection device 40 determines that the second shut-off valve 22 is faulty. Thus, the second fault detection routine DF2 is completed when the determination result is output in step S26 or step S27.

[0051] When the first fault detection routine DF1 and the second fault detection routine DF2 are completed, all fault detection routines are finished. After all fault detection routines have finished, the fault detection device 40 executes the process in step S28. In the process in step S28, the fault detection device 40 stops the hydrogen engine 15. Then, the fault detection device 40 completes the series of processes shown in Figures 2 and 3.

[0052] <Processing when the second fault detection routine DF2 is terminated> If the fault detection device 40 determines in step S29 that the user has turned on the ignition switch (step S29: YES), it executes the process in step S30.

[0053] In step S30, the fault detection device 40 opens the first shut-off valve 21 and the second shut-off valve 22. This opens all shut-off valves installed in the fuel supply system 10. As a result, hydrogen gas is supplied from the fuel tank 11 to the operating hydrogen engine 15.

[0054] As shown in Figure 3, after executing the process in step S30, the fault detection device 40 terminates the series of processes shown in Figures 2 and 3. In this case, the fault detection device 40 terminates the series of processes shown in Figures 2 and 3 without determining whether or not the second shut-off valve 22 is faulty. In other words, if the ignition switch is turned on while the second fault detection routine DF2 is being executed, the fault detection device 40 cancels the second fault detection routine DF2.

[0055] <Operation of this embodiment> While the fault detection routine is running, hydrogen gas is not supplied from the fuel tank 11, thus limiting the amount of fuel the hydrogen engine 15 can use.

[0056] The fault detection device 40 opens the shut-off valve when an operation is received requesting the operation of the hydrogen engine 15 while the fault detection routine is running. In other words, the fault detection device 40 stops the running fault detection routine and resumes the supply of hydrogen gas from the fuel tank 11.

[0057] <Effects of this embodiment> (1) When the fault detection device 40 receives an operation from the user requesting the operation of the hydrogen engine 15 before the fault detection routine is completed, it can quickly resume fuel supply and bring the vehicle into a state where it can be operated according to the user's operation.

[0058] (2) The fuel supply system 10 is equipped with multiple shut-off valves. The fault detection device 40 performs a fault detection routine with the shut-off valves downstream of the target shut-off valve open, changing the target shut-off valve sequentially from the upstream side. If the user requests the operation of the hydrogen engine 15 while the fault detection device 40 is executing the fault detection routine, it opens all shut-off valves and stops the fault detection routine.

[0059] If any of the shut-off valves are closed, hydrogen gas cannot be supplied from the fuel tank 11 to the hydrogen engine 15. When the fault detection device 40 is requested to operate the hydrogen engine 15 while a fault detection routine is being executed for any of the shut-off valves, it opens all of the shut-off valves. This allows the fault detection device 40 to resume supplying hydrogen gas from the fuel tank 11 to the hydrogen engine 15 in response to an operation requesting the operation of the hydrogen engine 15, even if the fuel supply system 10 has multiple shut-off valves.

[0060] (3) The fuel supply system 10 includes a regulator 13 on the hydrogen piping 12 that adjusts the pressure of the hydrogen gas supplied from the fuel tank 11 to the hydrogen engine 15. The fuel supply system 10 includes a first shut-off valve 21 installed in the hydrogen piping 12 between the fuel tank 11 and the regulator 13 as a shut-off valve. The fuel supply system 10 also includes a second shut-off valve 22 installed in the hydrogen piping 12 between the regulator 13 and the hydrogen engine 15 as a shut-off valve. The fault detection device 40 executes a first fault detection routine DF1, which targets the first shut-off valve 21, while continuing to operate the hydrogen engine 15, with the first shut-off valve 21 closed and the second shut-off valve 22 open. The fault detection device 40 executes a second fault detection routine DF2, which targets the second shut-off valve 22, while continuing to operate the hydrogen engine 15, with both the first shut-off valve 21 and the second shut-off valve 22 closed. If the user requests the hydrogen engine 15 to start while the first fault detection routine DF1 is being executed, the fault detection device 40 opens the first shut-off valve 21 and cancels the first fault detection routine DF1 while the hydrogen engine 15 continues to run. If the user requests the hydrogen engine 15 to start while the second fault detection routine DF2 is being executed, the fault detection device 40 opens the first shut-off valve 21 and the second shut-off valve 22 and cancels the second fault detection routine DF2 while the hydrogen engine 15 continues to run.

[0061] The fuel supply system 10 is equipped with two shut-off valves, a first shut-off valve 21 and a second shut-off valve 22, flanking the regulator 13. The fault detection device 40 executes a fault detection routine for each of the first shut-off valve 21 and the second shut-off valve 22, and when the operation of the hydrogen engine 15 is requested during the execution of the fault detection routine, it opens both the first shut-off valve 21 and the second shut-off valve 22. This allows the fault detection device 40 to resume supplying hydrogen gas from the fuel tank 11 to the hydrogen engine 15 in response to an operation requesting the operation of the hydrogen engine 15, provided that the fuel supply system 10 is equipped with both the first shut-off valve 21 and the second shut-off valve 22.

[0062] (4) The above fault determination method includes the step (step S11) in which, when a user of a vehicle equipped with a fuel supply system 10 requests that the hydrogen engine 15 be stopped, the fault determination device 40 closes the shut-off valve and, while continuing to operate the hydrogen engine 15, observes the rate of decrease in hydrogen gas pressure downstream of the shut-off valve, and if the rate of decrease is slow, starts a fault determination routine in which it determines that the shut-off valve has not been closed properly. The above fault determination method includes the step (steps S19 and S29) in which the fault determination device 40 determines that a user has requested that the hydrogen engine 15 be started. The fault determination method includes the step (steps S20 and S30) in which, when a user requests that the hydrogen engine 15 be started while the fault determination routine is being executed, the fault determination device 40 opens the shut-off valve while continuing to operate the hydrogen engine 15 and cancels the fault determination routine.

[0063] The above fault detection method opens the shut-off valve when an operation requesting the hydrogen engine 15 to operate occurs while the fault detection routine is running. In other words, the above fault detection method stops the running fault detection routine and restarts the supply of hydrogen gas from the fuel tank 11.

[0064] As a result, the above-described fault detection method can quickly resume fuel supply and bring the vehicle into a state where it can be operated according to the user's input if the user requests the operation of the hydrogen engine 15 before the fault detection routine is completed.

[0065] <Example of changes> This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0066] The fuel supply system 10 described above includes two shut-off valves: a first shut-off valve 21 and a second shut-off valve 22. The number of shut-off valves in the fuel supply system 10 is not limited to the above embodiment. The fuel supply system 10 may have three or more shut-off valves. Alternatively, the fuel supply system 10 may have only one shut-off valve.

[0067] The fuel supply system 10 described above has a regulator 13. The fuel supply system 10 does not necessarily have to have a regulator 13. The fault detection device 40 described above changes the shut-off valves targeted by the fault detection routine sequentially from the upstream side. However, the manner in which the fault detection device 40 changes the targets of the fault detection routine is not limited to the above embodiment. For example, the fault detection device 40 may change the shut-off valves targeted by the fault detection routine sequentially from the downstream side. [Explanation of Symbols]

[0068] 10…Fuel supply system, 11…Fuel tank, 12…Hydrogen piping, 13…Regulator, 15…Hydrogen engine, 21…First shut-off valve, 22…Second shut-off valve, 31…First pressure sensor, 32…Second pressure sensor, 40…Fault detection device, DF1…First fault detection routine, DF2…Second fault detection routine, HS…High pressure section, LS…Low pressure section

Claims

1. A hydrogen engine that uses hydrogen gas as fuel, A fuel tank for storing the aforementioned hydrogen gas, A hydrogen pipeline that guides the hydrogen gas from the fuel tank to the hydrogen engine, A shut-off valve is provided in the middle of the hydrogen piping to shut off the supply of hydrogen gas from the fuel tank to the hydrogen engine, This is a fault determination device applied to a fuel supply system comprising the shut-off valve and the hydrogen engine, which controls the shut-off valve and the hydrogen engine to determine whether or not there is a malfunction in the shut-off valve. When a user of a vehicle equipped with the fuel supply system requests the shutdown of the hydrogen engine, the shut-off valve is closed, and while the hydrogen engine continues to operate, the rate of pressure drop of the hydrogen gas downstream of the shut-off valve is observed. If the rate of pressure drop is slow, a fault determination routine is executed to determine that the shut-off valve has not been properly closed. If the user requests the hydrogen engine to start while the fault detection routine is running, the shut-off valve will be opened and the fault detection routine will be stopped while the hydrogen engine continues to run. Failure determination device.

2. The fuel supply system is equipped with a plurality of shut-off valves, and the fault determination routine is executed with the shut-off valve downstream of the target shut-off valve open, changing the target shut-off valve sequentially from the upstream side. If the user requests the hydrogen engine to start while the fault detection routine is running, all shut-off valves will be opened and the fault detection routine will be terminated. The fault detection device according to claim 1.

3. The fuel supply system is The hydrogen piping is provided with a regulator that adjusts the pressure of the hydrogen gas supplied from the fuel tank to the hydrogen engine. As the aforementioned shut-off valve, A first shut-off valve installed in the hydrogen piping between the fuel tank and the regulator, The hydrogen piping comprises a second shut-off valve installed in the portion between the regulator and the hydrogen engine, With the first shut-off valve closed and the second shut-off valve open, the fault determination routine targeting the first shut-off valve is executed while the hydrogen engine continues to operate. With the first shut-off valve and the second shut-off valve closed, the fault determination routine targeting the second shut-off valve is executed while the hydrogen engine continues to operate. If the user requests the operation of the hydrogen engine while the fault determination routine targeting the first shut-off valve is being executed, the first shut-off valve is opened while the hydrogen engine continues to operate, and the fault determination routine targeting the first shut-off valve is terminated. If the user requests the operation of the hydrogen engine while the fault determination routine for the second shut-off valve is being executed, the first and second shut-off valves are opened while the hydrogen engine continues to operate, and the fault determination routine targeting the second shut-off valve is terminated. The fault detection device according to claim 2.

4. A hydrogen engine that uses hydrogen gas as fuel, A fuel tank for storing the aforementioned hydrogen gas, A hydrogen pipeline that guides the hydrogen gas from the fuel tank to the hydrogen engine, A shut-off valve is provided in the middle of the hydrogen piping to shut off the supply of hydrogen gas from the fuel tank to the hydrogen engine, This is a fault determination method applied to a fuel supply system comprising the shut-off valve and the hydrogen engine, which controls the shut-off valve and determines whether or not there is a malfunction in the shut-off valve. When a user of a vehicle equipped with the fuel supply system requests the hydrogen engine to be stopped, the fault detection device closes the shut-off valve and, while continuing to operate the hydrogen engine, observes the rate of pressure drop of the hydrogen gas downstream of the shut-off valve, and if the rate of drop is slow, starts a fault detection routine that determines that the shut-off valve has not been closed properly. The fault detection device determines that the user has performed an operation to request the operation of the hydrogen engine, The fault determination device includes the step of opening the shut-off valve and terminating the fault determination routine while the hydrogen engine continues to run, when the user requests the hydrogen engine to start during the execution of the fault determination routine. Failure determination method.

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