Control device

Abstract

The control device is suitable for a fuel supply system. The control device is capable of controlling the hydrogen engine and first and second shut-off valves, which are shut-off valves. The control device executes a malfunction determination routine in which, when an operation for requesting to stop the hydrogen engine is performed by a user of a vehicle provided with a fuel supply system, the fuel supply system stops the hydrogen engine on the basis of closing the shut-off valve. In a state in which the operation of the hydrogen engine is continued, the decrease speed of the pressure of the hydrogen gas downstream of the shut-off valve is observed, and when the decrease speed is slower, it is determined that the shut-off valve is not normally closed. The control device stops the failure determination routine when the hydrogen engine is stopped due to engine stall during execution of the failure determination routine.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a control device. BACKGROUND

[0002] Japanese Patent Application Publication No. 2000-274311 describes a control device in a fuel supply system. The fuel supply system has 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 delivered to the hydrogen engine through a hydrogen pipe. The fuel supply system has a shut-off valve on the hydrogen pipe. The shut-off valve cuts off the hydrogen gas delivered from the fuel tank to the hydrogen engine in the hydrogen pipe.

[0003] The control device controls the hydrogen engine and the shut-off valve in the fuel supply system. The control device executes a failure determination routine. In the failure determination routine, the control device determines whether the shut-off valve has failed based on a change in pressure of the hydrogen gas in a portion between the shut-off valve and the hydrogen engine while the shut-off valve is closed and the hydrogen engine is consuming the hydrogen gas. The state in which the shut-off valve has failed as referred to herein is a state in which the shut-off valve does not normally close and the hydrogen gas is not cut off in the hydrogen pipe.

[0004] Engine stall can sometimes occur during execution of the failure determination routine. There is room for improvement regarding countermeasures in the case where engine stall occurs during execution of the failure determination routine. SUMMARY

[0005] According to an aspect of the present disclosure, there is provided a control device that is a control device of a fuel supply system, the fuel supply system having: a hydrogen engine configured to use hydrogen gas as fuel; a fuel tank configured to store the hydrogen gas; a hydrogen pipe configured to guide the hydrogen gas from the fuel tank to the hydrogen engine; a shut-off valve provided midway through the hydrogen pipe and configured to cut off supply of the hydrogen gas from the fuel tank to the hydrogen engine; and an injector configured to inject the hydrogen gas into the hydrogen engine, wherein the control device has a processing circuit configured to control the shut-off valve and the hydrogen engine, the processing circuit performs a failure determination routine in accordance with a situation in which an operation to request stop of the hydrogen engine is performed by a user of a vehicle having the fuel supply system, the failure determination routine includes: observing a rate of decrease in pressure of the hydrogen gas on a downstream side of the shut-off valve while continuing operation of the hydrogen engine on the basis of control performed in such a way as to close the shut-off valve; and determining that the shut-off valve does not normally close on the basis of a situation in which the rate of decrease is slower than in the case where the shut-off valve normally closes, and the processing circuit is configured to suspend the failure determination routine in accordance with a situation in which the hydrogen engine stops due to engine stall during execution of the failure determination routine. BRIEF DESCRIPTION OF DRAWINGS

[0006] Figure 1 This is a schematic diagram showing the structure of a fuel supply system having a control device according to one embodiment.

[0007] Figure 2 It means Figure 1 The flowchart shows a series of processes executed by the control device in the first fault determination routine.

[0008] Figure 3 It means Figure 1 The flowchart shows a series of processes executed by the control device in the second fault determination routine.

[0009] Figure 4 It is a flowchart illustrating the series of processes performed by the control device when the engine stalls during vehicle operation. Detailed Implementation

[0010] The following is for reference Figures 1-4 One embodiment of the control device will be described.

[0011] <Structure of Fuel Supply System 10>

[0012] The fuel supply system 10 is mounted on the vehicle.

[0013] Fuel tank 11 stores hydrogen supplied from an external source. For example... Figure 1 As shown, fuel tank 11 is connected to hydrogen engine 15 via hydrogen piping 12. Hydrogen piping 12 guides hydrogen from fuel tank 11 to hydrogen engine 15. The hydrogen introduced into hydrogen engine 15 is injected into the cylinder of hydrogen engine 15 through the injector of hydrogen engine 15.

[0014] The hydrogen engine 15 outputs driving force to a vehicle equipped with a fuel supply system 10 by burning hydrogen as fuel in a cylinder. Figure 1 As shown, a speed sensor 14 is installed in the hydrogen engine 15. The speed sensor 14 measures the speed of the hydrogen engine 15.

[0015] like Figure 1 As shown, a regulator 13, multiple shut-off valves, and multiple pressure sensors are installed in the middle of the hydrogen piping 12.

[0016] The regulator 13 adjusts the pressure of the hydrogen to a level usable by the hydrogen engine 15 by reducing the pressure of the hydrogen supplied from the fuel tank 11 to the hydrogen engine 15.

[0017] exist Figure 1The diagram shows the high-pressure section HS and the low-pressure section LS in hydrogen piping 12. The high-pressure section HS is the portion of hydrogen piping 12 that passes through before passing through regulator 13. The low-pressure section LS is the portion of hydrogen piping 12 that passes through after passing through regulator 13.

[0018] like Figure 1 As shown, the fuel supply system 10 includes a first shut-off valve 21 and a second shut-off valve 22 as multiple shut-off valves. The shut-off valves cut off the supply of hydrogen from the fuel tank 11 to the hydrogen engine 15.

[0019] like Figure 1 As shown, the first shut-off valve 21 is located in the section between the fuel tank 11 and the regulator 13 in the hydrogen piping 12. When the first shut-off valve 21 is closed, the high-pressure zone HS is cut off.

[0020] like Figure 1 As shown, the second shut-off valve 22 is located in the section of the hydrogen piping 12 between the regulator 13 and the hydrogen engine 15. When the second shut-off valve 22 is closed, the low-pressure zone LS is cut off.

[0021] like Figure 1 As shown, the fuel supply system 10 includes a first pressure sensor 31 and a second pressure sensor 32 as multiple pressure sensors. Figure 1 As shown, the first pressure sensor 31 is located in the high-pressure zone HS, downstream of the first shut-off valve 21. Figure 1 As shown, the second pressure sensor 32 is located in the low-pressure zone LS, downstream of the second shut-off valve 22.

[0022] like Figure 1 As shown, the fuel supply system 10 includes a control device 40.

[0023] like Figure 1 As shown, the control device 40 is communicatively connected to the hydrogen engine 15. The control device 40 is capable of controlling the operation of the hydrogen engine 15.

[0024] like Figure 1 As shown, the control device 40 is communicatively connected to the first shut-off valve 21 and the second shut-off valve 22. The control device 40 is capable of controlling the opening and closing of the first shut-off valve 21 and the second shut-off valve 22.

[0025] like Figure 1 As shown, the control device 40 is communicatively connected to the first pressure sensor 31 and the second pressure sensor 32. The control device 40 is able to acquire the values ​​measured by the first pressure sensor 31 and the second pressure sensor 32.

[0026] like Figure 1As shown, the control device 40 is communicatively connected to the speed sensor 14. The control device 40 is able to obtain the value measured by the speed sensor 14.

[0027] <Fault Diagnosis Routine>

[0028] The control device 40 executes a fault determination routine. This routine is a series of processes performed by the control device 40 to determine whether the shut-off valve is faulty. A shut-off valve fault, as referred to here, means a situation where the shut-off valve fails to close properly despite the control device 40 commanding it to do so. For example, this fault occurs when a foreign object is trapped between the shut-off valve components.

[0029] Figure 1 and Figure 2 This illustrates the process flow of a series of processes executed by the control device 40 during a fault determination routine. Figure 3 and Figure 2 The series of processes shown are executed when the ignition switch is turned off. Turning off the ignition switch is an operation by which the user requests to stop the hydrogen engine 15.

[0030] At the instant the ignition switch is turned off, the control device 40 starts the hydrogen engine 15 and opens the first shut-off valve 21 and the second shut-off valve 22. After turning off the ignition switch, the control device 40 performs a fault diagnosis routine while the hydrogen engine 15 continues to run.

[0031] <Handling methods in the first fault diagnosis routine DF1>

[0032] Figure 3 The processing in steps S11 to S17 shown is the first fault determination routine DF1. The first fault determination routine DF1 is a fault determination routine that determines whether the first shut-off valve 21 has a fault.

[0033] In step S11, the control device 40 closes the first shut-off valve 21. At this time, the control device 40 keeps the second shut-off valve 22 in the open state.

[0034] In step S12, the control device 40 obtains pressure P1. Pressure P1 is the pressure of hydrogen gas downstream of the first shut-off valve 21 immediately after the first shut-off valve 21 is closed. The control device 40 obtains pressure P1 from the first pressure sensor 31.

[0035] In step S13, the control device 40 determines whether a predetermined time t1 has elapsed since the first shut-off valve 21 was closed. The predetermined time t1 is determined in advance.

[0036] If the control device 40 determines in step S13 that the specified time t1 has not elapsed (step S13: no), the process proceeds to step S18.

[0037] In step S18, the control device 40 determines whether engine shutdown occurred during the execution of the first fault determination routine DF1. The control device 40 determines that engine shutdown has occurred when the speed of the hydrogen engine 15 obtained from the speed sensor 14 becomes zero.

[0038] If the control device 40 determines in step S18 that no engine stall has occurred (step S18: No), it will execute step S13 again.

[0039] If, during the processing in step S13, the control device 40 determines that a predetermined time t1 has elapsed (step S13: Yes), the processing proceeds to step S14. During the processing in step S14, the control device 40 acquires pressure P2. Pressure P2 is the pressure of hydrogen gas located downstream of the first shut-off valve 21 after the predetermined time t1 has elapsed since the first shut-off valve 21 was closed. The control device 40 acquires pressure P2 from the first pressure sensor 31.

[0040] In step S15, the control device 40 determines whether the difference between pressure P1 and pressure P2 is greater than or equal to the threshold N1.

[0041] In the first fault diagnosis routine DF1, the hydrogen flowing in the hydrogen piping 12 downstream of the first shut-off valve 21 is gradually consumed by the hydrogen engine 15 over a specified time t1. When the first shut-off valve 21 is not properly closed, the rate of pressure drop of the hydrogen downstream of the first shut-off valve 21 is slower compared to when the first shut-off valve 21 is properly closed.

[0042] During steps S12 to S15, the control device 40 observes the rate of pressure decrease of the hydrogen gas downstream of the first shut-off valve 21. The difference between pressure P1 and pressure P2 reflects the rate of pressure decrease of the hydrogen gas downstream of the first shut-off valve 21.

[0043] The threshold N1 is predetermined by the manufacturer of the control device 40. The manufacturer of the control device 40 sets the threshold N1, for example, based on the difference between pressure P1 and pressure P2 measured when the first shut-off valve 21 is normally closed.

[0044] If, during the processing in step S15, the control device 40 determines that the difference between pressure P1 and pressure P2 is greater than or equal to a threshold N1 (step S15: Yes), the processing proceeds to step S16. During the processing in step S16, the control device 40 determines that the first shut-off valve 21 has not malfunctioned.

[0045] If, during the processing in step S15, the control device 40 determines that the difference between pressure P1 and pressure P2 is less than a threshold N1 (step S15: No), the process proceeds to step S17. A difference between pressure P1 and pressure P2 less than the threshold N1 indicates that the pressure drop rate of hydrogen downstream of the first shut-off valve 21 is slower than when the first shut-off valve 21 is normally closed. During the processing in step S17, the control device 40 determines that the first shut-off valve 21 has malfunctioned. Thus, during the processing in step S16 or step S17, the first fault determination routine DF1 is completed by outputting the determination result.

[0046] <Handling procedures in the event of aborting the first fault determination routine DF1>

[0047] If the control device 40 determines in step S18 that the engine has stalled (step S18: yes), it executes step S19.

[0048] In step S19, the control device 40 closes the second shut-off valve 22. This brings all shut-off valves of the fuel supply system 10 to a closed state.

[0049] like Figure 2 As shown, after executing step S19, the control device 40 causes... Figure 3 and Figure 2 The series of processes shown here has ended. In this case, the control device 40 does not determine whether the first shut-off valve 21 is faulty, and the process ends. Figure 3 and Figure 2 The series of processes shown. That is, when the hydrogen engine 15 stops due to engine shutdown during the execution of the first fault determination routine DF1, the control device 40 stops the first fault determination routine DF1.

[0050] <Handling methods in the second fault diagnosis routine DF2>

[0051] like Figure 3 As shown, when the first fault determination routine DF1 is completed, the control device 40 causes the processing to enter step S20 and starts the second fault determination routine DF2. The second fault determination routine DF2 is a fault determination routine that determines whether the second shut-off valve 22 is faulty. Figure 3 The processing in steps S20 to S26 shown is the second fault determination routine DF2. In this way, the control device 40 executes the fault determination routine while sequentially changing the shut-off valves targeted from upstream.

[0052] In step S20, the control device 40 closes the second shut-off valve 22.

[0053] In step S21, the control device 40 obtains pressure P3. Pressure P3 is the pressure of hydrogen gas downstream of the second shut-off valve 22 immediately after the second shut-off valve 22 is closed. The control device 40 obtains pressure P3 from the second pressure sensor 32.

[0054] In step S22, the control device 40 determines whether a predetermined time t2 has elapsed since the second shut-off valve 22 was closed. The predetermined time t2 is predetermined.

[0055] If, during the processing in step S22, the control device 40 determines that the predetermined time t2 has not elapsed (step S22: No), the processing proceeds to step S28. During the processing in step S28, the control device 40 determines whether engine stall occurred during the execution of the second fault determination routine DF2.

[0056] If the control device 40 determines in step S28 that no engine stall has occurred (step S28: No), it will execute step S22 again.

[0057] If, during the processing in step S22, the control device 40 determines that a predetermined time t2 has elapsed (step S22: Yes), the processing proceeds to step S23. During the processing in step S23, the control device 40 acquires pressure P4. Pressure P4 is the pressure of hydrogen gas located downstream of the second shut-off valve 22 after a predetermined time t2 has elapsed since the second shut-off valve 22 was closed. The control device 40 acquires pressure P4 from the second pressure sensor 32.

[0058] In step S24, the control device 40 determines whether the difference between pressure P3 and pressure P4 is greater than or equal to the threshold N2.

[0059] In the second fault diagnosis routine DF2, the hydrogen flowing in the hydrogen piping 12 downstream of the second shut-off valve 22 is gradually consumed by the hydrogen engine 15 over a specified time t2. When the second shut-off valve 22 is not properly closed, the rate of pressure drop of the hydrogen downstream of the second shut-off valve 22 is slower compared to when the second shut-off valve 22 is properly closed.

[0060] The difference between pressure P3 and pressure P4 reflects the rate of pressure drop of hydrogen gas downstream of the second shut-off valve 22. During steps S21 to S24, the control device 40 observes the rate of pressure drop of hydrogen gas downstream of the second shut-off valve 22.

[0061] Threshold N2, like threshold N1, is predetermined by the manufacturer of control device 40. The manufacturer of control device 40 sets threshold N2, for example, based on the difference between pressure P3 and pressure P4 measured when the second shut-off valve 22 is normally closed.

[0062] If, during the processing in step S24, the control device 40 determines that the difference between pressure P3 and pressure P4 is greater than or equal to a threshold N2 (step S24: Yes), the processing proceeds to step S25. During the processing in step S25, the control device 40 determines that the second shut-off valve 22 has not malfunctioned.

[0063] If, during the processing in step S24, the control device 40 determines that the difference between pressure P3 and pressure P4 is less than the threshold N2 (step S24: No), the process proceeds to step S26. The difference between pressure P3 and pressure P4 being less than the threshold N2 indicates that the pressure drop rate of hydrogen downstream of the second shut-off valve 22 is slower than when the second shut-off valve 22 is normally closed. During the processing in step S26, the control device 40 determines that the second shut-off valve 22 has malfunctioned. Thus, in either step S25 or step S26, the second fault determination routine DF2 is completed by outputting the determination result.

[0064] When the first fault determination routine DF1 and the second fault determination routine DF2 are completed, all fault determination routines end. After all fault determination routines have ended, the control device 40 executes the processing in step S27. In the processing of step S27, the control device 40 stops the hydrogen engine 15. Then, the control device 40 causes... Figure 3 and Figure 2 The series of processes shown has ended.

[0065] <Handling procedures in the event of aborting the second fault detection routine DF2>

[0066] If the control device 40 determines in step S28 that an engine shutdown has occurred (step S28: Yes), it will... Figure 3 and Figure 2 The series of processes shown here has ended. In this case, the control device 40 does not determine whether the second shut-off valve 22 is faulty, and the process ends. Figure 3 and Figure 2 The series of processes shown are as follows. That is, when the hydrogen engine 15 stops due to engine shutdown during the execution of the second fault determination routine DF2, the control device 40 stops the second fault determination routine DF2. At this time, the control device 40 terminates the second fault determination routine DF2 with all shut-off valves of the fuel supply system 10 closed.

[0067] <Processing performed by control device 40 in the event of engine stall during vehicle operation>

[0068] During vehicle operation, control device 40 operates hydrogen engine 15 according to the vehicle's driving status. During vehicle operation, control device 40 opens first shut-off valve 21 and second shut-off valve 22 while operating hydrogen engine 15.

[0069] Figure 3 This illustrates a series of processes performed by the control unit 40 in the event that the engine stalls while the vehicle is in motion.

[0070] If the engine stalls while the vehicle is in motion, the control device 40 executes step S31. At the moment the engine stalls while the vehicle is in motion, the first shut-off valve 21 and the second shut-off valve 22 are open. During step S31, the control device 40 closes the first shut-off valve 21 and the second shut-off valve 22.

[0071] In step S32, the control device 40 determines whether the vehicle user has performed an operation to turn the ignition switch on (IG-ON). Turning the ignition switch on is an operation that requests the hydrogen engine 15 to start.

[0072] If the control device 40 determines in step S32 that the operation of turning on the ignition switch has not been performed (step S32: No), it executes step S32 again. If the control device 40 determines in step S32 that the operation of turning on the ignition switch has been performed (step S32: Yes), it proceeds to step S33.

[0073] In step S33, the control device 40 opens the first shut-off valve 21 and the second shut-off valve 22. This allows hydrogen from the fuel tank 11 to be supplied to the hydrogen engine 15.

[0074] In step S34, control device 40 starts the hydrogen engine 15. Thus, control device 40 can restart vehicle operation after an engine shutdown. Control device 40, having started the hydrogen engine 15, then terminates the process. Figure 4 Figure 4 The series of processes shown.

[0075] <The function of this implementation method>

[0076] If the engine stalls during the execution of the fault diagnosis routine, the hydrogen in the hydrogen piping 12 is no longer consumed. Therefore, if the engine stalls during the execution of the fault diagnosis routine, the rate of pressure drop of the hydrogen downstream of the shut-off valve is slower compared to the case where the engine does not stall. Therefore, if the engine stalls during the execution of the fault diagnosis routine, the control device 40 may mistakenly determine that the shut-off valve has malfunctioned. If the engine stalls during the execution of the fault diagnosis routine, the control device 40 terminates the fault diagnosis routine.

[0077] <Effects of this implementation method>

[0078] (1) The control device 40 can suppress the false determination of the shut-off valve failure when the engine stalls during the execution of the fault determination routine.

[0079] (2) The fuel supply system 10 is equipped with multiple shut-off valves. The control device 40 executes a fault determination routine while sequentially changing the shut-off valves to be targeted from the upstream side, with the shut-off valves downstream of the targeted shut-off valves open. When the hydrogen engine 15 stops due to engine shutdown during the execution of the fault determination routine, the fuel supply system 10 closes all shut-off valves and stops the fault determination routine.

[0080] Even if the injector stops injecting hydrogen due to engine shutdown, hydrogen may still leak from the injector into the hydrogen engine 15. The control unit 40 executes a fault determination routine with the downstream shut-off valve (the valve targeted) open. Therefore, if engine shutdown occurs during the fault determination routine, hydrogen that has already passed through the open shut-off valve may leak from the injector into the non-operating hydrogen engine 15.

[0081] If an engine stalls during the execution of a fault diagnosis routine, the control device 40 shuts off all shut-off valves of the fuel supply system 10. This reduces the amount of hydrogen leaking from the injectors into the non-operating hydrogen engine 15.

[0082] (3) The fuel supply system 10 has a regulator 13 on the hydrogen piping 12 for regulating the pressure of hydrogen supplied from the fuel tank 11 to the hydrogen engine 15. The fuel supply system 10 has a first shut-off valve 21 and a second shut-off valve 22 as shut-off valves. The first shut-off valve 21 is located in the portion of the hydrogen piping 12 between the fuel tank 11 and the regulator 13. The second shut-off valve 22 is located in the portion of the hydrogen piping 12 between the regulator 13 and the hydrogen engine 15. When the first shut-off valve 21 is closed and the second shut-off valve 22 is open, the control device 40 continues to operate the hydrogen engine 15 while executing a fault determination routine, i.e., a first fault determination routine DF1, targeting the first shut-off valve 21. When both the first shut-off valve 21 and the second shut-off valve 22 are closed, the control device 40 continues to operate the hydrogen engine 15 while executing a fault determination routine, i.e., a second fault determination routine DF2, targeting the second shut-off valve 22. During the execution of the first fault determination routine DF1, when the hydrogen engine 15 stops due to engine shutdown, the control device 40 closes the second shut-off valve 22 while keeping the first shut-off valve 21 closed, and terminates the first fault determination routine DF1. During the execution of the second fault determination routine DF2, when the hydrogen engine 15 stops due to engine shutdown, the control device 40 terminates the second fault determination routine DF2 while keeping the first shut-off valve 21 and the second shut-off valve 22 closed.

[0083] The fuel supply system 10 includes two shut-off valves, a first shut-off valve 21 and a second shut-off valve 22, separated by a regulator 13. The control device 40 executes fault determination routines for both the first shut-off valve 21 and the second shut-off valve 22, and terminates these routines when engine shutdown occurs, with both valves closed. Thus, in the fuel supply system 10 equipped with the first shut-off valve 21 and the second shut-off valve 22, the control device 40 can reduce the amount of hydrogen leaking from the injector into the hydrogen engine 15 when engine shutdown occurs during the execution of the fault determination routine.

[0084] (4) During vehicle operation, the control device 40 operates the hydrogen engine 15 according to the vehicle's driving status and opens the shut-off valve when the hydrogen engine 15 is operated. When the hydrogen engine 15 stops due to engine shutdown during vehicle operation, the shut-off valve closes.

[0085] During vehicle operation, the control device 40 opens the shut-off valve while the hydrogen engine 15 is running. Therefore, during vehicle operation, the shut-off valve is open at the instant the hydrogen engine 15 stops due to engine shutdown.

[0086] In the event of engine shutdown during vehicle operation, control device 40 closes the shut-off valve. Therefore, when engine shutdown occurs during vehicle operation, control device 40 can reduce the amount of hydrogen leaking from the injector into the non-operating hydrogen engine 15.

[0087] (5) After the control device 40 closes the shut-off valve when the engine stalls during vehicle operation, it starts the hydrogen engine 15 after opening the shut-off valve when the user requests the operation of the hydrogen engine 15.

[0088] If the engine stalls while the vehicle is in motion, the control device 40 will start the hydrogen engine 15 when the user requests the engine to restart, allowing the vehicle to resume driving. However, if the amount of hydrogen injected by the injector is insufficient when the control device 40 starts the hydrogen engine 15, the engine may stall again.

[0089] After the control device 40 opens the shut-off valve to allow the injector to utilize the hydrogen in the fuel tank 11, it starts the hydrogen engine 15. Thus, the control device 40 can prevent engine shutdown when the hydrogen engine 15 restarts.

[0090] <Example of Change>

[0091] The above-described embodiments can be implemented by modification as follows. The above-described embodiments and the following modifications can be combined with each other within the scope of technical inconsistency.

[0092] 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 also have three or more shut-off valves. Alternatively, the fuel supply system 10 may have only one shut-off valve.

[0093] The fuel supply system 10 described above has a regulator 13. The fuel supply system 10 may also not have a regulator 13.

[0094] The control device 40 described above sequentially changes the shut-off valves that are the objects of the fault determination routine from the upstream side. The manner in which the control device 40 changes the objects of the fault determination routine is not limited to the embodiment described above. For example, the control device 40 may also sequentially change the shut-off valves that are the objects of the fault determination routine from the downstream side.

[0095] • Control device 40 may also not close all shut-off valves if the hydrogen engine 15 stops due to engine shutdown during the execution of the fault determination routine. For example, if the hydrogen engine 15 stops due to engine shutdown during the execution of the first fault determination routine DF1, control device 40 may not close the second shut-off valve 22.

[0096] • The control device 40 can keep the shut-off valve open even if the hydrogen engine 15 stops due to engine shutdown during vehicle operation.

[0097] • The control device 40 described above closes all shut-off valves in the event that the engine stalls while the vehicle is in motion. Alternatively, the control device 40 may close only a portion of the multiple shut-off valves in the event that the engine stalls while the vehicle is in motion.

[0098] • The control device 40 can also open the shut-off valve after the hydrogen engine 15 is started when the user requests the operation of the hydrogen engine 15, after the shut-off valve is closed due to the engine shutdown that occurs during vehicle operation.

[0099] The operation of requesting the operation of the hydrogen engine 15 is not limited to turning on the ignition switch. For example, the operation of requesting the operation of the hydrogen engine 15 could also be the operation of turning the engine key. For example, the operation of requesting the operation of the hydrogen engine 15 could also be the operation of pressing the start switch.

[0100] The control device 40 includes a CPU (Central Processing Unit), RAM (Random Access Memory), and ROM (Read Only Memory). The control device 40 performs software processing. However, this is only an example. For instance, the control device 40 may also include dedicated hardware circuitry for processing at least a portion of the software processing performed in the above embodiment. The dedicated hardware circuitry is, for example, an ASIC (Application Specific Integrated Circuit). That is, the control device 40 can be any of the following structures (a) to (c): (a) The control device 40 includes a processing unit that performs all processing according to a program and a program storage device such as a ROM that stores the program. That is, the control device 40 includes a software execution unit. (b) The control device 40 includes a processing unit that performs a portion of the processing according to a program and a program storage device. Furthermore, the control device 40 includes dedicated hardware circuitry for performing the remaining processing. (c) The control device 40 includes dedicated hardware circuitry for performing all processing. Here, there may be multiple software execution units and / or dedicated hardware circuitry. That is, the above-described processing can be executed by at least one of a processing circuitry having a software execution device and dedicated hardware circuitry. The processing circuitry may include multiple software execution devices and dedicated hardware circuitry. The program storage device, i.e., computer-readable medium, includes all available media, i.e., storage devices, that can be accessed by a general-purpose or special-purpose computer.

Claims

1. A control device that is a control device of a fuel supply system that has: a hydrogen engine configured to use hydrogen gas as fuel; a fuel tank that stores the hydrogen gas; a hydrogen pipe that guides the hydrogen gas from the fuel tank to the hydrogen engine; a cut valve that is provided midway through the hydrogen pipe and configured to cut off supply of the hydrogen gas from the fuel tank to the hydrogen engine; and an injector configured to inject the hydrogen gas into the hydrogen engine, the control device having a processing circuit configured to control the cut valve and the hydrogen engine, the processing circuit performing a failure determination routine in accordance with a situation in which an operation that requests stop of the hydrogen engine is performed by a user of a vehicle that has the fuel supply system, the failure determination routine including: observing a rate of decrease in pressure of the hydrogen gas on a downstream side of the cut valve in a state in which operation of the hydrogen engine is continued on the basis of control in a manner in which the cut valve is closed; and determining that the cut valve is not normally closed on the basis of a situation in which the rate of decrease is slower than in a case in which the cut valve is normally closed, the processing circuit being configured to suspend the failure determination routine in accordance with a situation in which the hydrogen engine is stopped due to engine stall during execution of the failure determination routine.

2. The control device according to claim 1, wherein the cut valve is a first cut valve, the fuel supply system further has a second cut valve that is provided midway through the hydrogen pipe and configured to cut off supply of the hydrogen gas from the fuel tank to the hydrogen engine, the second cut valve being provided at a downstream side of the first cut valve, the failure determination routine further includes: determining whether the first cut valve is normally closed in a state in which the second cut valve is open; observing a rate of decrease in pressure of the hydrogen gas on a downstream side of the second cut valve in a state in which operation of the hydrogen engine is continued on the basis of control in a manner in which the second cut valve is closed; and determining that the second cut valve is not normally closed on the basis of a situation in which the rate of decrease is slower than in a case in which the second cut valve is normally closed, the processing circuit being configured to close the first cut valve and the second cut valve and suspend the failure determination routine in accordance with a situation in which the hydrogen engine is stopped due to the engine stall during execution of the failure determination routine.

3. The control device according to claim 2, wherein the fuel supply system further has a regulator on the hydrogen pipe, the regulator being configured to regulate pressure of the hydrogen gas that is supplied from the fuel tank toward the hydrogen engine, the first cut valve is provided in a portion of the hydrogen pipe between the fuel tank and the regulator, the second cut valve is provided in a portion of the hydrogen pipe between the regulator and the hydrogen engine. ​ ​ ​ wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ the processing circuitry is configured to, during execution of the failure determination routine for the first shutoff valve, in accordance with the hydrogen engine stopping due to the engine being turned off, control the second shutoff valve to be closed while continuing to control the first shutoff valve to be closed, and suspend the failure determination routine for the first shutoff valve, the processing circuitry is configured to, during execution of the failure determination routine for the second shutoff valve, in accordance with the hydrogen engine stopping due to the engine being turned off, continue to control the first shutoff valve and the second shutoff valve to be closed, and suspend the failure determination routine for the second shutoff valve.

4. The control device according to any one of claims 1 to 3, wherein the processing circuitry is configured to, during travel of the vehicle, operate the hydrogen engine in accordance with a travel state of the vehicle, and during operation of the hydrogen engine, open the shutoff valve, the processing circuitry is configured to, in accordance with the hydrogen engine stopping due to the engine being turned off during travel of the vehicle, control the shutoff valve to be closed.

5. The control device according to claim 4, wherein the processing circuitry is configured to, after being controlled to be closed in association with the engine being turned off during travel of the vehicle, in accordance with the user performing an operation requesting operation of the hydrogen engine, operate the hydrogen engine after being controlled to be opened.

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