JP2004095425A - Supply on-off valve failure diagnosis system - Google Patents

Abstract

A system for promptly diagnosing a failure of a supply on-off valve at startup is provided.
A first on-off valve provided in a fuel gas supply pipe for supplying a fuel gas, a second on-off valve provided downstream of the first on-off valve, and between the first and second on-off valves. A first pressure sensor 6 for detecting the pressure of the fuel gas. Furthermore, a stop-time on-off valve operation unit that closes in the order of the first on-off valve 8 and the second on-off valve 9 at the time of stop, a stop-time storage processing unit that stores an output of the first pressure sensor 6 at the time of stop, and a stop-time and operation restart A failure diagnosis unit that compares the output of the first pressure sensor 6 at the time to determine the failure of the first and second on-off valves 8 and 9.
[Selection diagram] Fig. 1

Description

[0001]
[Industrial applications]
The present invention relates to a failure diagnosis device for a fuel cell system. In particular, the present invention relates to a system for performing a failure diagnosis of a supply on-off valve by performing a leakage diagnosis of a supply on-off valve of a fuel gas supply system.
[0002]
[Prior art]
As a conventional failure diagnosis device for a fuel gas supply on-off valve, there is one disclosed in Japanese Patent Application Laid-Open No. 9-22711. This includes a first on-off valve and a second on-off valve from the upstream side in a fuel gas supply pipe for supplying fuel gas to the fuel cell, and further measures the pressure between the first on-off valve and the second on-off valve A hydrogen gas pressure sensor. At start-up, the first on-off valve and the second on-off valve are closed, and a failure diagnosis of the first on-off valve is performed based on the gas pressure detected by the hydrogen gas pressure sensor. Subsequently, the first on-off valve is opened for a predetermined time and then closed again, and a failure diagnosis of the second on-off valve is performed based on the gas pressure detected by the hydrogen gas pressure sensor after a lapse of a predetermined time from the closing.
[0003]
[Problems to be solved by the invention]
However, since it is necessary to supply gas to the fuel gas supply pipe in order to detect a leak, if a failure has already occurred before the start-up, for example, a failure during operation stop starts the fuel supply. Cannot be detected. Further, when performing a failure diagnosis before starting, it is necessary to secure a diagnosis time, so that the time until traveling or starting operation is extended.
[0004]
Accordingly, an object of the present invention is to provide a failure diagnosis system for a supply on-off valve that can promptly perform a failure on the supply on-off valve at the time of startup.
[0005]
[Means for solving the problem]
The present invention provides a fuel cell that generates power using fuel gas, a fuel gas tank that stores fuel gas supplied to the fuel cell, a fuel gas supply pipe that supplies fuel gas from the fuel gas tank to the fuel cell, A first on-off valve disposed on the fuel gas supply pipe, a second on-off valve disposed downstream of the first on-off valve along a flow direction of the fuel gas, the first on-off valve and the second on-off valve A first pressure sensor that detects the pressure of the fuel gas between the first pressure sensor and the first pressure sensor. Further, when the fuel cell is stopped, the first on-off valve is closed and then the second on-off valve is closed, and the second on-off valve is operated when the fuel cell is stopped, and the output of the first pressure sensor is stored when the fuel cell is stopped. The pressure storage unit compares the output of the first pressure sensor when the operation is restarted after the fuel cell is stopped with the output of the first pressure sensor when the fuel cell is stopped stored in the stop-time pressure storage unit. A failure diagnosis unit that determines whether at least one of the first on-off valve and the second on-off valve has failed.
[0006]
[Action and effect]
When the fuel cell is stopped, the pressure in the fuel supply pipe is measured, and when the fuel cell is restarted, the pressure when the fuel cell is stopped is compared with the pressure when the operation is restarted.From the comparison result, at least the first on-off valve and the second on-off valve are used. Determine if one is faulty. Thus, a failure can be detected without supplying fuel gas to the fuel cell. Further, there is no need to wait for running or starting operation for failure diagnosis. Thereby, the failure diagnosis of the first on-off valve and the second on-off valve can be quickly performed at the time of startup.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a configuration of a failure diagnosis system for a supply on-off valve (first and second on-off valves 8 and 9 described later) used in the present embodiment.
[0008]
The fuel cell 1 is supplied with an oxidant gas from an oxidant gas supply system (not shown) and a fuel gas from the fuel supply system. An electrochemical reaction occurs between oxygen in the oxidant gas and hydrogen in the fuel gas. Is generated to generate power.
[0009]
The fuel supply system includes a fuel gas tank 2 serving as a fuel gas storage tank and a fuel gas supply pipe 3 serving as a fuel gas flow passage. The fuel gas is supplied from the fuel gas tank 2 to the fuel cell 1 via the fuel gas supply pipe 3. Supply. The first on-off valve 8, the second on-off valve 9, and the third on-off valve 10 are arranged in the fuel gas supply pipe 3 from the upstream side along the fuel gas flow direction. Here, the first and second on-off valves 8 and 9 adjust the supply and stop of the fuel gas, and the third on-off valve 10 is adjusted so as to keep the pressure of the fuel electrode of the fuel cell 1 constant.
[0010]
The first volume section 11 formed by a part of the fuel gas supply pipe 3 between the first opening / closing valve 8 and the second opening / closing valve 9 includes a first temperature sensor 5 and a first pressure sensor 6. The temperature T1 and the pressure P1 in the one volume section 11 can be detected. The second volume 12 formed by a part of the fuel gas supply pipe 3 between the second on-off valve 9 and the third on-off valve 10 is provided with the second pressure sensor 7, Pressure P2 can be detected. Further, a pressure sensor 4 is provided in the fuel gas tank 2 so that the pressure Pt in the tank can be detected.
[0011]
In such a failure diagnosis system, a controller 20 is provided, which controls the first to third on-off valves 8 to 10 from the output of each sensor, and performs a failure diagnosis of the first and second on-off valves 8 and 9 at startup. Do.
[0012]
Next, a control method by the controller 20 of such a failure diagnosis system of the supply on-off valve will be described. The control method of the present embodiment includes a stop processing unit shown in FIG. 2 that is performed when the operation of the fuel cell 1 is stopped, and a diagnostic processing unit that is performed when the operation of the fuel cell 1 is started. Constitute.
[0013]
First, a control method of the stop processing unit when the fuel cell 1 is stopped will be described with reference to FIG.
[0014]
When the command to stop the operation of the fuel cell 1 is output, the process proceeds to a stop processing determination unit in step S1. The stop processing determination unit determines whether or not to perform a stop processing for performing a failure diagnosis of the supply on-off valve at the next start-up, and actually performs control as shown in FIG.
[0015]
In FIG. 4, when a stop processing unit start command is received, the process proceeds to step S7, and it is determined whether the pressure Pt in the fuel gas tank 2 is larger than a predetermined value DGNPt. If it is larger than the predetermined value DGNPt, the process proceeds to step S8, where it is determined that the stop processing is performed by setting the stop processing flag FDGNV = 1. On the other hand, if it is determined in step S7 that the pressure Pt is equal to or less than the predetermined value DGNPt, the process proceeds to step S9, where the stop processing flag FDGNV is set to 0, and it is determined that the stop processing is not performed.
[0016]
Here, when the pressure in the fuel gas tank 2 is small, the difference between the pressures in the fuel gas tank 2, the first volume section 11, and the second volume section 12 becomes small even if a stop process described later is performed. In such a case, even if there is no fuel gas leakage, the fuel cell is easily affected by the environmental change, and there is a possibility that the supply on-off valve is erroneously determined to be faulty. Therefore, if there is a possibility of such a misdiagnosis, here, if the pressure in the fuel gas tank 2 is equal to or lower than the predetermined value DGNPt, it is set that no failure determination is performed at the next startup, and the fuel cell 1 To stop.
[0017]
After the stop processing determination is performed in this manner, the process proceeds to the stop processing operation unit in step S2 in FIG. The stop processing operation unit performs processing for performing a failure diagnosis of the supply on-off valve at the next start-up, and actually performs control as shown in the flowchart of FIG.
[0018]
In step S10 in FIG. 5, it is determined whether or not the stop processing flag FDGNV obtained by the stop processing determination unit (S1 in FIG. 2) is 1. If it is determined that the stop processing flag FDGNV is not 1, the stop processing is not performed, so the process proceeds to step S15, and the first to third on-off valves 8 to 10 are simultaneously closed, for example, and the control in the stop processing operation unit is ended. Here, the first to third on-off valves 8 to 10 are closed at the same time, but this is not a limitation.
[0019]
On the other hand, when the stop processing flag FDGNV is 1 in step S10, the process proceeds to step S11, and a timing tm1 for closing the first on-off valve 8 is calculated. FIG. 6 shows a method for obtaining the timing tm1.
[0020]
After confirming the command for calculating tm1, in step S26, if the supply on / off valve is supported to be closed, the first opening / closing 8 is immediately closed, that is, tm1 = 0 is set. After setting tm1 in step S11 (FIG. 6), the process proceeds to step S12.
[0021]
In step S12, a timing tm2 for closing the second on-off valve 9 is calculated. The method of calculating the timing tm2 will be described with reference to the flowchart shown in FIG.
[0022]
When the command for obtaining the timing tm2 is confirmed, the process proceeds to step S17, and the target set pressure TGP2 at which the pressure P2 of the second volume 12 finally calms down is read. This is, for example, the pressure of the fuel electrode of the fuel cell 1 during shutdown.
[0023]
Proceeding to step S18, a difference ΔDP (= Pt−TGP2) between the current pressure Pt of the fuel gas tank 2 and the set pressure of the second volume section 12 is determined. Proceeding to step S19, the timing tm2 is obtained from a map or the like showing the timing tm2 for the difference ΔDP shown in FIG. Here, for example, the map of FIG. 8 shows a timing tm2 such that P1 = TGP2 + (Pt−TGP2) / 2, which is obtained in advance through experiments or the like, that is, P1 is an intermediate value between Pt and TGP2. Here, the timing tm2 is obtained from the map, but the output of the first pressure sensor 6 may be monitored, and the time when P1 = TGP2 + (Pt−TGP2) / 2 may be set as the timing tm2.
[0024]
When the timing tm2 is obtained in step S13 (FIG. 7), the process proceeds to step S14 in FIG. In step S14, a timing tm3 for closing the third on-off valve 10 is obtained. The timing tm3 is determined using the flowchart shown in FIG.
[0025]
After confirming the command for obtaining the timing tm3, the process proceeds to step S20 in FIG. 9, and the timing when the pressure P2 of the first volume section 12 reaches the set pressure TGP2 is set as the timing tm3. That is, the output of the second pressure sensor 7 is detected, and the time when the value becomes TGP2 is defined as the timing tm3 for closing the third on-off valve 10.
[0026]
After setting the timing tm3 in step S13 (FIG. 9), the process proceeds to step S14 in FIG. 5, and the first to third on-off valves 8 to 10 are closed according to the timings tm1 to tm3 obtained in steps S11 to S13.
[0027]
As described above, when the control of the stop processing operation unit in step S2 (FIG. 5) is completed, the process proceeds to step S3, and the stop-time storage processing unit is performed. Here, control as shown in FIG. 10 is performed.
[0028]
That is, when a command to start the stop-time storage process is received, in step S21 in FIG. 10, the pressure Pt in the fuel gas tank 2, the pressure P1 and the temperature T1 in the first volume 11, and the temperature T1 in the second volume 12 The pressure P2 and the stop processing flag FDGNP are stored in the memory.
[0029]
When the control of the storage processing unit at the time of termination is terminated in this way, the termination processing in FIG. 2 is terminated. Here, FIG. 14 shows an example of a timing chart when the operation of the stop processing as shown in FIG. 2 is performed.
[0030]
When the pressure in the fuel gas tank 2 is higher than the predetermined pressure DGNPt, when the first on-off valve 8 is closed, the first on-off valve 8 is located on the downstream side of the first on-off valve 8 (first and second volume parts) as compared with the pressure P1 in the fuel gas tank 2. 11, 12) The pressure decreases. This is because the fuel cell 1 still consumes hydrogen at this point, and the fuel gas is flowing toward the fuel cell 1. Similarly, when the second on-off valve 9 is closed, the pressure in the first volume section 11 maintains the pressure at that time, whereas the pressure on the downstream side (the second volume section 12) of the second on-off valve 9 becomes It drops further. After that, by closing the third on-off valve 10, the pressure in the second volume portion 12 maintains the pressure at the time when the third on-off valve 10 is closed. Therefore, when there is no failure in the first to third on-off valves 8 to 10, Pt>P1> P2 is maintained. Here, the timing tm2 is set so that the pressure differences between Pt and P1 and between P1 and P2 are substantially the same.
[0031]
Next, a failure diagnosis method performed when the fuel cell 1 is started will be described with reference to the flowchart of FIG.
[0032]
In step S4, the storage memory is called according to the flowchart shown in FIG. When a command to call the storage memory is received, the process proceeds to step S22 to call the value stored in the memory. Here, the values stored in the memory in step S21 of FIG. 10, that is, the pressure Pt in the fuel gas tank 2, the pressure P1 and the temperature T1 in the first volume 11, the pressure P2 in the second volume 12, Read the stop processing flag FDGNP. In step S23, each value is applied to variables MPt, MP1, MP2, MT1, and MFDGNP for use in the calculation.
[0033]
When the storage memory is called in step S4 (FIG. 11), the process proceeds to step S5. The failure diagnosis determination unit in step S5 determines whether to perform failure diagnosis according to the control shown in FIG.
[0034]
In step S24 of FIG. 12, the absolute value | T1-MT1 | of the temperature difference between the temperature T1 of the first volume section 11 and the temperature MT1 of the first volume section 11 stored in the memory, and the predetermined value DGNT1 To compare. If the absolute value | T1−MT1 | is larger than DGNT1, the process proceeds to step S27, and the diagnosis permission flag FDGNP = 0 is set so that the failure diagnosis is not performed.
[0035]
On the other hand, if the absolute value | T1-MT1 | is equal to or smaller than DGNT1, the process proceeds to step S25 to compare the pressure Pt of the fuel gas tank 2 with the pressure MPt of the fuel gas tank 2 stored in the memory. Thus, it is determined whether the fuel gas has been replenished to the fuel gas tank 2 during the period from the previous stop to the start of the current start. If the difference (Pt-MPt) between the current pressure and the previous pressure is larger than the predetermined value DGNPF, it is determined that the fuel gas has been replenished, and the process proceeds to step S27, where the diagnosis permission flag FDGNP = 0 is set so that failure diagnosis is not performed. Set. On the other hand, if (Pt-MPt) is equal to or less than DGNPF, it is determined that replenishment has not been performed, and the process proceeds to step S25, where a diagnosis permission flag FDGNP = 1 is set so that failure diagnosis is performed.
[0036]
If the temperature at startup is significantly different from the temperature at the previous stop, the pressure change will increase irrespective of the state of leakage of the supply on-off valve, and the supply on-off valve will fail erroneously. May be determined to be Therefore, the failure diagnosis is performed when the influence of the pressure change on the failure diagnosis is negligible, in this case, when the absolute value | T1-MT1 | is less than or equal to DGNT1, and in other cases, the start is started without performing the failure diagnosis. . Therefore, the temperature used as the criterion is not limited to the output of the first temperature sensor 5 and may be determined based on the temperature of the fuel gas in the fuel gas tank 2 or the like. Further, by checking the change in the pressure in the fuel gas tank 2, it is determined whether or not the fuel gas has been replenished during the stop. If the fuel gas has been replenished, the fuel cell 1 is started without performing a failure diagnosis.
[0037]
If it is determined in step S5 (FIG. 12) whether to perform a failure diagnosis, the process proceeds to step S6. The failure diagnosis unit in step S6 performs control as shown in FIG.
[0038]
In step S28, it is determined whether or not the diagnosis permission flag FDGNP = 1 and MDGNP = 1. Unless FDNGP = 1 and MFDNGP = 1, the failure diagnosis is not performed. Therefore, the process proceeds to step S36, and the failure result flag FDGNOK = 1, the first on-off valve failure flag FDGNV1 = 0, and the second on-off valve failure flag FDGNV2 = 0 are set. I do. Here, the failure result flag indicates whether or not there is a failure as a result of the diagnosis. If FDGNOK = 1, it is normal, and if FDGNOK = 0, at least one of the first on-off valve 8 and the second on-off valve 9 is provided. Indicates a failure. Further, the first on-off valve failure flag FDGNV1 and the second on-off valve failure flag FDGNV2 indicate the failure diagnosis results of the respective supply on-off valves, where 1 indicates failure and 0 indicates normal. I have. That is, when it is determined in step S28 that the failure diagnosis is not to be performed, it is determined that the failure is normal, the failure diagnosis is terminated, and the fuel cell 1 is started.
[0039]
On the other hand, if FDGNP = 1 and MFDGNP = 1 in step S28, a failure diagnosis is performed, and the process proceeds to step S29. In step S29, the pressure P1 of the first volume section 11 is corrected by the temperature. That is, P ₀ Assuming that 1 = P1 × MT1 / T1, the correction pressure P is taken into account in consideration of pressure changes due to temperature ₀ 1 is calculated. In step S30, the temperature-corrected pressure P ₀ 1 is compared with the pressure MP1 stored in the memory. Here, P ₀ 1 is greater than MP1, and whether the difference is greater than a predetermined value DPA1 ₀ It is determined whether 1-MP1> DPA1. Here, the predetermined value DPA1 is a value for avoiding misdiagnosis due to a change in environment or a measurement error.
[0040]
If it is larger than the predetermined value DPA1, it is determined that the pressure in the first volume section 11 has become higher than at the time of the previous stop. Then, the process proceeds to step S31, in which it is determined that the fuel gas has been supplied from the fuel gas tank 2 to the first volume portion 11 through the first on-off valve 8, and thereby it is determined that the first on-off valve 8 has failed. Therefore, the diagnosis result flag FDGNOK = 0 and the first on-off valve failure flag FDGNV1 = 1 are set to indicate that the first on-off valve 8 has a failure. At this time, the second on-off valve failure flag FDGNV2 = 0 is set, and the failure diagnosis ends.
[0041]
On the other hand, in step S30, P ₀ If it is determined that 1-MP1> DPA1, it is determined that FDGNV1 = 0, that is, that the first on-off valve 8 has no failure, and then proceeds to step S33.
[0042]
Next, in step S33, MP1 ₀ 1 and whether the difference is greater than a predetermined value DPB1, that is, MP1-P ₀ It is determined whether 1> DPB1. Here, the predetermined value DPB1 is also a value for avoiding a misdiagnosis due to a change in environment or a measurement error.
[0043]
If it is larger than the predetermined value DPB1, it is determined that the pressure in the first volume section 11 has become smaller than at the time of the previous stop. Then, the process proceeds to step S34, and it is considered that the fuel gas in the first volume 11 has moved to the second volume 12 having a lower pressure via the second on-off valve 9, and the second on-off valve 9 has failed. Is determined. Therefore, the failure result flag FDGNOK = 0 and the second on-off valve failure flag FDGNV2 = 1 are set, and the failure diagnosis ends.
[0044]
On the other hand, if it is not determined in step S33 that the second on-off valve 9 has failed, the process proceeds to step S35, where the failure result flag FDGNOK = 1 and the second on-off valve failure flag FDGNV2 = 0 are set, and the failure diagnosis ends. I do.
[0045]
If the failure result flag FDGNOK, which is the above result, is 1, it is understood that it is normal, and if it is 0, it is failure. When FDGNOK is 0, it is possible to determine which of the first on-off valve 8 and the second on-off valve 9 has failed from the results of FDGNV1 and FDGNV2.
[0046]
Next, effects of the present embodiment will be described.
[0047]
This embodiment includes a fuel cell 1, a fuel gas tank 2, a fuel gas supply pipe 3 for supplying a fuel gas from the fuel gas tank 2 to the fuel cell 1, a first on-off valve 8 disposed in a fuel gas supply passage, A second on-off valve 9 arranged downstream of the one on-off valve 8 and a first pressure sensor 6 for detecting the pressure of the first volume 11 are provided. Further, when the fuel cell 1 is stopped, the first on-off valve 8 is closed, and then the second on-off valve 9 is closed. A storage processing unit (S3) is provided. Further, the output of the first pressure sensor 6 when the operation is restarted after the stop is compared with the stored output of the first pressure sensor 6 when the stop is performed, and at least the first on-off valve 8 and the second on-off valve 9 are compared. A failure diagnosis unit (S6) for determining whether one of them has failed. Thereby, a failure can be detected without supplying fuel to the fuel cell 1. Further, since there is no need to wait for traveling or operation start for the failure diagnosis, the failure diagnosis can be performed promptly at the time of startup.
[0048]
Further, a third on-off valve 10 is provided between the second on-off valve 9 and the fuel cell 1, and the third on-off valve 10 is closed after the second on-off valve 9 is closed in the stop-time on-off valve operation section (S14). By providing the third on-off valve 10 as described above, the pressure on the downstream side of the second on-off valve 9 can be kept constant when there is no failure. Thereby, even when a pressure change occurs in the fuel cell 1, a failure of the second on-off valve can be accurately determined.
[0049]
A pressure sensor 4 for measuring the pressure of the fuel gas tank 2, a second pressure sensor 7 for detecting the pressure of the second volume 12, and a stop-time on-off valve control for setting a timing for closing the first to third on-off valves 8 to 10 Means (S11 to S13). At the time of stop, the first to third on-off valves 8 to 10 are closed according to the set timing according to the outputs of the pressure sensor 4, the first pressure sensor 6, and the second pressure sensor 7. Thereby, it is possible to stop with the pressure difference between the fuel gas tank 2 and the first volume 11 and the pressure difference between the first volume 11 and the second volume 12, so that the first on-off valve 8 can be stopped during the stop. Thus, it is possible to detect the leakage of the fuel gas from the second on-off valve 9. Here, in particular, since the pressure difference between the fuel gas tank 2 and the first volume 11 and the pressure difference between the first volume 11 and the second volume 12 are set to be substantially the same, the first and second volumes are set. The failure of the on-off valves 8 and 9 can be similarly detected.
[0050]
A stop processing determination unit (S1) for determining whether to perform a stop operation based on the state of the fuel gas stored in the fuel gas tank 2 is provided. This makes it possible to avoid the stop operation and the failure diagnosis when the subsequent failure diagnosis cannot be accurately performed even if the stop operation is performed, so that a misdiagnosis can be avoided and unnecessary operation is omitted. can do.
[0051]
For example, a pressure sensor 4 that measures the pressure of the fuel gas tank 2 is provided, and when the output of the pressure sensor 4 is equal to or more than a predetermined value, it is determined that the stop operation is performed. When the pressure in the fuel gas tank 2 is low, the difference between the pressure of the fuel gas tank 2 and the pressures of the first and second volume portions 11 and 12 is small even when the stop processing is performed. In some cases, the supply opening / closing valve is erroneously diagnosed. Therefore, this can be avoided by performing the stop processing only when the pressure in the fuel gas tank 2 is equal to or higher than the predetermined value.
[0052]
A pressure sensor 4 for measuring the pressure of the fuel gas tank 2 and temperature detecting means for detecting or estimating a temperature change of the fuel gas in at least one portion of the fuel gas tank 2 or the fuel gas supply pipe 3, here a first temperature sensor 5. Prepare. A failure diagnosis determining unit (S5) for determining whether to perform a failure diagnosis based on the pressure and temperature of the fuel gas immediately before the restart of the operation after the stop. Thus, in a case where the state of the fuel gas significantly changes due to a change in the environment or the like and a misdiagnosis is likely to occur, a failure diagnosis can be avoided. As a result, more accurate failure diagnosis can be performed.
[0053]
When the difference between the output of the first temperature sensor 5 at the time of the previous stop and the output of the first temperature sensor 5 immediately before restarting the operation of the fuel cell 1 is equal to or more than a predetermined value, No fault diagnosis is performed. If the temperature at the start is far away from the temperature at the previous stop, the change in pressure becomes large irrespective of the state of leakage of the first and second on-off valves 8 and 9, resulting in an erroneous failure. There is a possibility of judgment. Therefore, when the output of the first temperature sensor 5 is significantly different between the time of the stop and the time of the start, the failure diagnosis is not performed, so that erroneous diagnosis can be avoided.
[0054]
A first temperature sensor 5 is provided between the first on-off valve 8 and the second on-off valve 9, and when the failure diagnosis unit (S <b> 6) makes a determination, the output of the first temperature sensor 5 at the time of the previous stop is determined. , The pressure is corrected based on the output of the first temperature sensor 5 when the operation is restarted. Thereby, even when the temperature at the time of starting has changed from the temperature at the time of the previous stop, the pressure can be compared.
[0055]
In the present embodiment, the fuel gas tank 2 is constituted by one tank, but may be constituted by a plurality of tanks. At that time, at least a first on-off valve 8 and a second on-off valve 9 are provided for each tank. With this configuration, failure diagnosis of the on-off valve can be performed regardless of the number of tanks.
[0056]
When the fuel gas is supplied to the fuel gas tank 2, for example, when a fuel reforming system is provided and the fuel gas is supplied to the fuel gas tank 2, the process proceeds to step S 1 in FIG. The illustrated stop processing determination unit may be omitted. Further, when TGP2 has a substantially constant value such as the outside air pressure, Pt and P2 have substantially constant values. Therefore, tm1 to tm3 are not obtained in steps S11 to S13 in FIG. 5, and Pt-P1 = P1 in FIG. Tm1 to tm3 that becomes -P2 can be obtained in advance by experiments or the like.
[0057]
As described above, the present invention is not limited to the above embodiment, and it goes without saying that various changes can be made within the scope of the technical idea described in the claims.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a failure diagnosis system for a supply on-off valve according to an embodiment.
FIG. 2 is a flowchart of a stop process according to the embodiment.
FIG. 3 is a flowchart of a diagnosis process according to the embodiment.
FIG. 4 is a flowchart of a stop processing determination according to the embodiment.
FIG. 5 is a flowchart of a stop processing operation in the embodiment.
FIG. 6 is a flowchart of tm1 calculation in the embodiment.
FIG. 7 is a flowchart of tm2 calculation in the embodiment.
FIG. 8 is a map used for obtaining tm2 in the flowchart of FIG. 7;
FIG. 9 is a flowchart of tm3 calculation in the embodiment.
FIG. 10 is a flowchart of a stop-time storage process in the embodiment.
FIG. 11 is a flowchart of a storage memory call in the embodiment.
FIG. 12 is a flowchart of a failure diagnosis determination according to the embodiment.
FIG. 13 is a flowchart of a failure diagnosis according to the present embodiment.
FIG. 14 is a timing chart at the time of a stop process in the embodiment.
[Explanation of symbols]
1 fuel cell
2 Fuel gas tank
3 Fuel gas supply piping
4 Supply unit pressure sensor (pressure sensor)
5 First temperature sensor (temperature detecting means, first temperature sensor)
6 First pressure sensor
7 Second pressure sensor
8 First open / close valve
9 Second on-off valve
10 Third open / close valve
20 Controller
S1 stop processing determination unit
S3 Stop-time storage processing unit
S5 Failure diagnosis determination unit
S6 Failure diagnosis unit
S14 Stop-time on-off valve operation unit
S11-13 Shutdown opening / closing control means

Claims (9)

A fuel cell that generates power using fuel gas,
A fuel gas tank for storing fuel gas to be supplied to the fuel cell;
A fuel gas supply pipe for supplying fuel gas from the fuel gas tank to the fuel cell,
A first on-off valve disposed on the fuel gas supply pipe,
A second on-off valve arranged downstream of the first on-off valve along the flow direction of the fuel gas,
A first pressure sensor that detects the pressure of the fuel gas between the first on-off valve and the second on-off valve,
When the fuel cell is stopped, a stop-time on-off valve operating unit that closes the second on-off valve after closing the first on-off valve,
A stop-time pressure storage unit that stores at least the output of the first pressure sensor when the fuel cell is stopped,
The output of the first pressure sensor when the operation is restarted after the fuel cell is stopped is compared with the output of the first pressure sensor when the fuel cell is stopped, which is stored in the stop-time pressure storage unit. A failure diagnosis system for a supply on-off valve, comprising: a failure diagnosis unit that determines whether at least one of the one on-off valve and the second on-off valve has failed. A third on-off valve is provided between the second on-off valve and the fuel cell,
The failure diagnosis system for a supply on-off valve according to claim 1, wherein the third on-off valve is closed after closing the second on-off valve in the stop-time on-off valve operating section. A supply pressure sensor for measuring the pressure of the fuel gas tank,
A second pressure sensor that detects the pressure of the fuel gas between the second on-off valve and the third on-off valve,
The first on-off valve, the second on-off valve, and the third on-off valve, the stop-time on-off valve control means to set the timing to close,
When the fuel cell is stopped, according to the output of the supply unit pressure sensor, the first pressure sensor, and the second pressure sensor, the stop-time on-off valve operating unit operates according to the timing set by the stop-time on-off valve control unit. The failure diagnosis system for a supply on-off valve according to claim 2, wherein the first on-off valve, the second on-off valve, and the third on-off valve are closed. The failure of the supply opening / closing valve according to claim 1, further comprising a stop processing determination unit that determines whether to perform a stop operation by the opening / closing valve operating unit based on the state of the fuel gas stored in the fuel gas tank. Diagnostic system. A supply unit pressure sensor for measuring the pressure of the fuel gas tank,
The failure diagnosis system for a supply on-off valve according to claim 4, wherein the stop processing determination unit determines that a stop operation is performed when an output of the supply unit pressure sensor is equal to or more than a predetermined value. A supply pressure sensor for measuring the pressure of the fuel gas tank,
Temperature detection means for detecting or estimating a change in the temperature of the fuel gas in at least one portion of the fuel gas tank or the fuel gas supply pipe,
2. The supply switch according to claim 1, further comprising: a failure diagnosis determination unit configured to determine whether to perform a failure diagnosis in the failure diagnosis unit based on a pressure and a temperature of the fuel gas when the operation is restarted after the fuel cell is stopped. Valve failure diagnosis system. In the failure diagnosis determination unit, when a difference between the output of the temperature detection unit at the time of the previous stop and the output of the temperature detection unit at the time of restarting operation of the fuel cell is equal to or more than a predetermined value, the failure is determined. The failure diagnosis system for a supply on-off valve according to claim 6, wherein it is determined that the failure diagnosis is not performed in the diagnosis unit. The failure diagnosis system for a supply on-off valve according to claim 1, wherein one or a plurality of the fuel gas supply tanks are mounted, and at least the first on-off valve and the second on-off valve are provided for each of the fuel gas supply tanks. A first temperature sensor provided between the first on-off valve and the second on-off valve,
A pressure correction is performed based on an output of the first temperature sensor at the time of a previous stop and an output of the first temperature sensor at the time of restarting operation of the fuel cell when making a determination in the failure diagnosis determination unit. 2. The failure diagnosis system for the supply on-off valve according to 1.

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