JP2008234970A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system preventing control error even when a pressure sensor fails. <P>SOLUTION: A fuel cell system resets a hydrogen consumption amount and detects an initial pressure inside a tank (S101) when generating power. Then, when the hydrogen consumption amount exceeds a prescribed value 1 (S102, Yes), a prescribed value 2 as the hydrogen consumption amount corresponding to the pressure for the prescribed value 1 is set (S103). Next, a tank inside pressure P2 when the prescribed value 1 is consumed is detected (S104) and whether or not the difference in pressure (P1-P2) is equal to or smaller than the prescribed value 2 is judged (S105). When the difference in pressure is equal to or smaller than the prescribed value 2 (S105, Yes), the pressure sensor inside the tank is judged to be defective (S106) and the power generation is stopped (S107). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell system provided with a sensor for detecting the amount of remaining hydrogen in a hydrogen tank.

For example, in a fuel cell vehicle, it is necessary to inform the driver of the remaining amount of hydrogen in the hydrogen tank. The driver can determine the approximate cruising distance by checking the remaining amount meter provided on the instrument panel, etc., and if it is determined that the remaining amount of hydrogen is low, hydrogen filling is necessary. It can be judged that there is. As a means to detect the remaining amount of hydrogen in the hydrogen tank, it is proposed to provide a sensor for detecting the temperature and pressure in the hydrogen tank and detect the remaining amount based on the temperature and pressure obtained from each sensor. (For example, refer to Patent Document 1).
JP 2004-63205 A (paragraph 0024, FIG. 1)

  However, since the conventional technology detects the remaining amount of hydrogen based on a pressure sensor that detects the pressure in the hydrogen tank, there is a problem that if this pressure sensor fails, the remaining amount of hydrogen cannot be accurately grasped. It was. For this reason, for example, if power generation is continued (erroneous control) in a state where hydrogen is depleted (gas is depleted on the electrolyte membrane), there is a risk of causing membrane deterioration of the fuel cell stack.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a fuel cell system capable of preventing erroneous control even if a pressure sensor fails.

  The invention according to claim 1 is a fuel cell stack that generates power by being supplied with a fuel gas and an oxidant gas, a fuel gas storage container that stores the fuel gas supplied to the fuel cell stack, and the fuel gas storage container A container internal pressure detecting means for detecting the internal pressure of the container, and a container internal temperature detecting means for detecting the temperature in the fuel gas storage container, based on the pressure and the temperature in the fuel gas storage container. A fuel consumption amount for calculating a fuel consumption amount of the fuel gas in a fuel cell system that estimates an amount of remaining fuel gas in the fuel gas storage container and controls operation of the fuel cell stack based on the remaining fuel gas amount Detected by a calculating means, a pressure threshold setting means for setting a pressure threshold corresponding to the pressure corresponding to the fuel consumption calculated by the fuel consumption calculating means, and the in-container pressure detecting means A pressure which is characterized by and a failure determination means for determining a failure of the container pressure detecting means on the basis of the set pressure threshold by the threshold pressure setting means.

  According to this, when the fuel cell stack generates electricity, the detected pressure in the fuel gas storage container is compared with the pressure threshold value set based on the amount of hydrogen consumption, thereby causing a failure of the pressure detection means in the container. Since the detection can be performed, it is possible to prevent the fuel cell system from being erroneously controlled when the container pressure detection means fails.

  According to a second aspect of the present invention, there is provided a fuel cell stack that generates power by being supplied with a fuel gas and an oxidant gas, a fuel gas storage container that stores the fuel gas supplied to the fuel cell stack, and the fuel gas storage container A container internal pressure detecting means for detecting the internal pressure of the container, and a container internal temperature detecting means for detecting the temperature in the fuel gas storage container, based on the pressure and the temperature in the fuel gas storage container. In a fuel cell system that estimates the amount of remaining fuel gas in the fuel gas storage container and controls the operation of the fuel cell stack based on the amount of remaining fuel gas, fuel consumption for calculating fuel consumption by the fuel cell stack An amount calculating means; a pressure estimating means for estimating a pressure in the fuel gas storage container based on the fuel consumption calculated by the fuel consumption calculating means; and a pressure detection in the container. Failure determination means for determining a failure of the in-container pressure detection means based on the pressure detected by the means and the pressure estimated by the pressure estimation means, and the failure determination means is the detected It is determined that the in-container pressure detecting means is out of order based on the difference between the estimated pressure and the estimated pressure.

  According to this, the failure detection of the in-container pressure detection means can be performed based on the detected pressure in the fuel gas storage container and the estimated pressure in the fuel gas storage container during power generation of the fuel cell stack. This makes it possible to prevent the fuel cell system from erroneously controlling when the in-container pressure detecting means fails.

  The invention according to claim 3 includes a temperature change amount detecting means for detecting a temperature change amount in the fuel gas storage container, and the failure determination means is based on the temperature change amount detected by the temperature change amount detecting means. And determining whether or not to perform failure determination.

  According to this, when the amount of change in temperature is too large, the pressure in the fuel gas storage container fluctuates greatly, so that accurate pressure detection cannot be performed. Therefore, it is possible to prevent erroneous detection of a failure by determining whether or not to perform failure detection based on the temperature change amount.

  The invention according to claim 4 is characterized in that power generation of the fuel cell stack is stopped when a failure is determined by the failure determination means.

  According to this, since power generation is stopped when there is a failure, it is possible to prevent film deterioration by causing power generation in a state where the amount of remaining fuel gas cannot be accurately grasped.

  According to a fifth aspect of the present invention, when the failure determination means determines that a failure has occurred, the fuel cell stack generates power from the amount of fuel gas in the fuel gas storage container calculated before the failure determination by the failure determination means. And subtracting the fuel consumption amount consumed by the above and the fuel consumption amount discharged by the purge process to calculate an alternative residual fuel gas amount.

  According to this, it becomes possible to continue the operation of the fuel cell system without stopping the power generation of the fuel cell stack.

  ADVANTAGE OF THE INVENTION According to this invention, even if a pressure sensor fails, the fuel cell system which can prevent erroneous control can be provided.

(First embodiment)
FIG. 1 is an overall configuration diagram showing the fuel cell system of the first embodiment, FIG. 2 is a flowchart showing failure determination control of the tank pressure sensor in the first embodiment, and FIG. It is a map which shows. In this embodiment, a case where the present invention is applied to a vehicle (not shown) will be described as an example. However, the present embodiment is not limited to this, and may be applied to an aircraft, a ship, a stationary power source, and the like. .

  As shown in FIG. 1, the fuel cell system 1 of this embodiment includes a fuel cell stack 10, an anode system 20, a cathode system 30, a control system 40, and the like.

  The fuel cell stack 10 includes a plurality of single cells in which an electrolyte membrane made of a solid polymer is sandwiched between an anode containing a catalyst and a cathode containing a catalyst, and the outside is sandwiched between a pair of conductive separators. Has a structured.

  The anode system 20 includes a hydrogen tank 21, an in-tank electromagnetic valve 22, a hydrogen regulator 23, an ejector 24, a purge valve 25, and the like. The in-tank solenoid valve 22 and the hydrogen regulator 23 are connected via a pipe 26a. Further, the hydrogen regulator 23 and the ejector 24 are connected via a pipe 26b. The ejector 24 and the anode inlet of the fuel cell stack 10 are connected via a pipe 26c. The anode outlet and the purge valve 25 are connected via a pipe 26d. The middle of the pipe 26d and the ejector 24 are connected via a pipe 26e.

  The hydrogen tank 21 is made of, for example, an aluminum alloy, and has a tank chamber (not shown) for storing high-purity hydrogen gas at a high pressure therein. The periphery of the tank chamber is CFRP (Carbon Fiber Reinforced Plastic). : Carbon fiber reinforced plastic) or a cover (not shown) formed of GFRP (Glass Fiber Reinforced Plastic) or the like.

  The in-tank solenoid valve 22 is configured integrally with the hydrogen tank 21 and opens and closes by controlling energization to the solenoid.

  The hydrogen regulator 23 has a pressure reducing function for reducing the high pressure hydrogen gas supplied from the hydrogen tank 21 to a predetermined pressure and supplying it to the fuel cell stack 10. For example, the hydrogen regulator 5 is opened when the pressure of the cathode system 30 is input as a signal pressure.

  The ejector 24 is a kind of vacuum pump for circulating unreacted hydrogen discharged from the anode of the fuel cell stack 10 back to the anode of the fuel cell stack 10.

  The purge valve 25 is provided on the downstream side of the pipe 26e of the pipe 26d, and has a function of periodically opening and closing to prevent the power generation performance from being impaired. This is because hydrogen is circulated in the anode system 20 as an effective use of hydrogen, and when power generation continues and impurities such as generated water and nitrogen permeate from the cathode to the anode through the electrolyte membrane, the hydrogen of the anode system 20 This is because the power generation performance is reduced due to a decrease in concentration.

  The cathode system 30 includes an air pump 31, a humidifier 32, a back pressure valve 33, pipes 34b to 34e, and the like. Moreover, the outlet of the air pump 31 and the inlet of the dry air (supply gas) of the humidifier 32 are connected via a pipe 34b. The air outlet after humidification of the humidifier 32 and the inlet of the cathode of the fuel cell stack 10 are connected via a pipe 34c. The outlet of the cathode and the inlet of the humid air (exhaust off gas) of the humidifier 32 are connected via a pipe 34d. The humid air outlet of the humidifier 32 and the back pressure valve 33 are connected via a pipe 34e.

  The air pump 31 is composed of a supercharger or the like driven by a motor, and has a function of supplying compressed air compressed by taking in outside air to the cathode of the fuel cell stack 10.

  The humidifier 32 includes, for example, a hollow fiber membrane module in which a plurality of water permeable membranes are bundled and accommodated in a case, and air from the air pump 31 is circulated on one side of the inside and outside of the hollow fiber membrane. It has a function of humidifying the dry air from the air pump 31 by circulating the exhaust off-gas (wet air, generated water) discharged from the cathode of the fuel cell stack 10 on the side.

  The back pressure valve 33 is constituted by, for example, a butterfly valve, and has a function of controlling the pressure of the cathode system 30 of the fuel cell stack 10 by controlling the opening thereof.

  A dilution box (not shown) is provided on the downstream side of the purge valve 25 and the downstream side of the back pressure valve 33, and is discharged from the anode system 20 of the fuel cell stack 10 when the purge valve 25 is opened. The hydrogen is diluted outside the system (outside the vehicle) after being diluted to a predetermined hydrogen concentration by the off-gas discharged from the cathode system 30 in the dilution box.

  The control system 40 includes an ECU (Electronic Control Unit) 41, a tank internal temperature sensor 42, a tank internal pressure sensor 43, and a flow rate sensor 44.

  The ECU 41 includes a CPU (Central Processing Unit), a memory, a program, and the like, and includes a fuel consumption calculation unit, a pressure threshold setting unit, and a failure determination unit according to this embodiment. The ECU 41 controls the opening / closing of the in-tank electromagnetic valve 22, the purge valve 25, and the back pressure valve 33 to control the rotation speed of the motor of the air pump 31. Note that the control lines of the purge valve 25 and the back pressure valve 33 are not shown. The ECU 41 is connected to a tank temperature sensor 42, a tank pressure sensor 43, and a flow rate sensor 44, which will be described later, through signal lines, and is configured to acquire the tank temperature, the tank pressure, and the flow rate. .

  The tank internal temperature sensor 42 is provided in the hydrogen tank 21 and has a function of detecting the temperature in the hydrogen tank 21. The tank internal temperature sensor 42 is configured integrally with the in-tank electromagnetic valve 22, for example.

  The tank internal pressure sensor 43 has a function of detecting the pressure in the hydrogen tank 21 and is provided in a pipe 26 a between the in-tank electromagnetic valve 22 and the hydrogen regulator 23. The tank internal pressure sensor 43 may be provided in the hydrogen tank 21.

  The flow sensor 44 has a function of detecting the flow rate of hydrogen supplied from the hydrogen tank 21 toward the fuel cell stack 10, and is provided, for example, in the pipe 26b (or the pipe 26a). In the present embodiment, the hydrogen consumption amount can be calculated by integrating the flow rate (detected value) obtained from the flow rate sensor 44. By providing the flow rate sensor 44 in the pipes 26a and 26b, hydrogen discharged from the fuel cell stack 10 and circulated is not added to the hydrogen consumption.

Next, the operation of the fuel cell system of the first embodiment will be described with reference to FIG. 2 (refer to FIG. 1 as appropriate).
First, in step S101, when the ignition is turned on and power generation is started or during power generation, the ECU 41 resets the hydrogen consumption stored in the memory or the like, and detects the inside of the hydrogen tank 21 detected by the tank pressure sensor 43. The tank internal pressure P1 is detected and stored. The amount of hydrogen consumed at this time is defined as an initial tank internal pressure P1. During power generation, the in-tank solenoid valve 22 is opened, hydrogen is supplied to the anode of the fuel cell stack 10, the air pump 31 is driven, and humidified air is supplied to the cathode, so that hydrogen and oxygen in the air are mixed. Electricity is generated by an electrochemical reaction.

  In step S102, the ECU 41 determines whether the hydrogen consumption calculated based on the flow rate (integrated flow rate) obtained from the flow rate sensor 44 exceeds a predetermined value 1. The predetermined value 1 is a value that is arbitrarily determined in advance. Further, this step S102 corresponds to the processing performed by the fuel consumption amount calculation means in the present embodiment. In step S102, when the ECU 41 determines that the hydrogen consumption is equal to or less than the predetermined value 1 (No), the ECU 41 repeats step S102 until the hydrogen consumption exceeds the predetermined value 1, and the hydrogen consumption reaches the predetermined value 1. If it is determined that it has exceeded (Yes), it is determined that a predetermined amount of hydrogen has been consumed, and the process proceeds to step S103.

  In step S103, the ECU 41 sets a predetermined value 2 (pressure threshold) corresponding to the pressure corresponding to the hydrogen consumption (predetermined value 1). This predetermined value 2 is set based on a map as shown in FIG. The map is not limited to the map, and may be set using a function or a table. In addition, this step S103 corresponds to the process which the pressure threshold value setting means in this embodiment implements.

  In step S104, the ECU 41 detects and stores the tank internal pressure P2 in the hydrogen tank 21 detected by the tank internal pressure sensor 43 when the hydrogen consumption exceeds a predetermined value 1.

  In step S105, the ECU 41 determines whether or not a pressure difference (P1-P2) obtained by subtracting the tank internal pressure P2 detected in step S104 from the initial tank internal pressure P1 detected in step S101 is smaller than a predetermined value 2. Judging. Note that step S105 corresponds to the process performed by the failure determination unit of the present embodiment.

  In step S105, when the ECU 41 determines that the pressure difference (P1-P2) is smaller than the predetermined value 2 (Yes), the ECU 41 proceeds to step S106, and determines that the tank pressure sensor 43 has failed. In step S105, if the ECU 41 determines that the pressure difference (P1-P2) is equal to or greater than the predetermined value 2 (No), the ECU 41 determines that the tank pressure sensor 43 is normal and proceeds to step S101. Return.

  The failure determination in step S105 will be described with a specific example. For example, when the initial tank internal pressure P1 is 35 MPa (350 atm) and a predetermined value 1 (hydrogen consumption) is consumed, 300 liters is consumed. When the value 2 (pressure threshold) is 3 MPa, if the tank pressure sensor 43 detects that the tank pressure P2 is 32 MPa, the detected pressure difference (P1−P2) becomes the same value at 3 MPa. Therefore, it is determined that the tank pressure sensor 43 is normal. When the tank pressure P2 detected by the tank pressure sensor 43 is detected to be 34 MPa, which is higher than the actual pressure, the pressure difference (P1−P2) is 1 MPa, and the predetermined value 2 (3 MPa). Therefore, it is determined that the tank pressure sensor 43 is out of order. When the tank pressure P2 detected by the tank pressure sensor 43 is detected to be 30 MPa, which is smaller than the actual pressure, the pressure difference (P1-P2) is 5 MPa, which is larger than the predetermined value 2. However, it is determined that the tank pressure sensor 43 is normal. In other words, in the present embodiment (step S105), only when the pressure difference (P1-P2) is smaller than the predetermined value 2 is determined as a failure, the pressure difference (P1-P2) is smaller than the predetermined value 2. The reason why the pressure is small is mainly to prevent the tank internal pressure P2 from being estimated more than the actual pressure, that is, determining that more hydrogen than the actual pressure remains in the hydrogen tank 21.

  If it is determined that the tank pressure sensor 43 has failed (S106, Yes), the process proceeds to step S107, and the power generation of the fuel cell stack 10 is stopped. That is, the in-tank electromagnetic valve 22 is closed to stop the supply of hydrogen from the hydrogen tank 21 to the anode of the fuel cell stack 10, and the air pump 31 is stopped to stop the supply of air to the cathode of the fuel cell stack 10.

  As described above, in the fuel cell system 1A of the first embodiment, during power generation, the pressure difference detected by the tank pressure sensor 43 is compared with the pressure threshold value set according to the hydrogen consumption amount. Since the failure of the pressure sensor 43 can be detected, it is possible to prevent erroneous control (described later) by the fuel cell system 1A when the tank pressure sensor 43 fails. For example, even in the case of a malfunction that erroneously detects that more hydrogen is left in the hydrogen tank 21 than in actuality, the malfunction of the tank pressure sensor 43 can be detected, so that power generation is not continued due to insufficient hydrogen. Further, it is possible to prevent erroneous control such that deterioration of the fuel cell stack 10, particularly the membrane (anode and cathode including the catalyst) progresses.

  Further, in the fuel cell system 1A of the first embodiment, when it is determined that the tank pressure sensor 43 is out of order, the power generation is stopped. Therefore, the power generation is performed without accurately grasping the remaining hydrogen amount. By continuing, it can prevent that film deterioration accelerates | stimulates.

(Second Embodiment)
FIG. 4 is an overall configuration diagram showing the fuel cell system of the second embodiment, and FIG. 5 is a flowchart showing failure determination control of the tank pressure sensor in the second embodiment. The difference between the fuel cell system 1B of the second embodiment and the fuel cell system 1A of the first embodiment is only that the current sensor 45 is used instead of the flow rate sensor 44. About the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  The current sensor 45 in the fuel cell system 1B has a function of detecting a current drawn from the fuel cell stack 10 toward a load (not shown). By integrating the current detected by the current sensor 45, the hydrogen consumption can be estimated. In addition, if it is a vehicle, a load will be auxiliary machines, such as a travel motor, an electrical storage apparatus, and the air pump 31, etc.

  As shown in FIG. 5, in step S201, the ignition is turned on, and at the start of power generation or during power generation, the ECU 41 resets the accumulated current stored in the memory or the like and is detected by the tank internal pressure sensor 43. The initial tank internal pressure P1 in the hydrogen tank 21 is detected and stored.

  In step S202, the ECU 41 determines whether or not the integrated value (integrated current amount) of the current detected by the current sensor 45 exceeds a predetermined value 3. The predetermined value 3 is a value that is arbitrarily determined in advance. Further, this step S202 corresponds to the processing executed by the fuel consumption amount calculation means in the present embodiment. In step S202, when the ECU 41 determines that the accumulated current amount is equal to or less than the predetermined value 3 (No), the ECU 41 repeats step S202 until the accumulated current amount exceeds the predetermined value 3, and the accumulated current amount reaches the predetermined value 3. If it is determined that it has exceeded (Yes), it is determined that a predetermined amount of hydrogen has been consumed, and the process proceeds to step S203.

  In this embodiment, for example, hydrogen that has not contributed to the reaction (unreacted hydrogen) may be purged (discharged) periodically by opening the purge valve 25, so that hydrogen consumption is based only on the accumulated current amount. Rather than calculating the amount, it is preferable to calculate the sum of the hydrogen consumption obtained from the integrated current amount and the hydrogen consumption obtained from the purge amount by purging as the hydrogen consumption amount. As the purge amount at this time, a value obtained in advance through experiments or the like can be used. In the present embodiment, the hydrogen consumption is calculated based on the current, but the present invention is not limited to this, and the hydrogen consumption is calculated based on voltage (V) or power (IV = W). You may do it.

  In step S203, the ECU 41 sets a predetermined value 4 (pressure threshold) corresponding to the pressure corresponding to the integrated current amount (predetermined value 3). The predetermined value 4 is set by a map, a table, a function, or the like. Further, this step S203 corresponds to the processing performed by the pressure threshold value setting means in the present embodiment.

  In step S204, the ECU 41 detects and stores the tank internal pressure P2 in the hydrogen tank 21 detected by the tank internal pressure sensor 43 when the integrated current amount exceeds the predetermined value 3.

  In step S205, the ECU 41 determines whether the pressure difference (P1-P2) obtained by subtracting the tank internal pressure P2 detected in step S204 from the initial tank internal pressure P1 detected in step S201 is smaller than a predetermined value 4. Judging. Note that step S205 corresponds to the process performed by the failure determination unit of the present embodiment.

  In step S205, when the ECU 41 determines that the pressure difference (P1-P2) is smaller than the predetermined value 4 (Yes), the ECU 41 proceeds to step S206, and determines that the tank pressure sensor 43 has failed. In step S205, if the ECU 41 determines that the pressure difference (P1-P2) is equal to or greater than the predetermined value 4 (No), the ECU 41 determines that the tank pressure sensor 43 is normal and proceeds to step S201. Return. Step S207 is the same as step S107 of the first embodiment.

  As described above, in the fuel cell system 1B of the second embodiment, the pressure difference (P1-P2) detected by the tank pressure sensor 43, the integrated current amount, and the purge amount during power generation, as in the first embodiment. Since the failure of the tank pressure sensor 43 can be detected by comparing the pressure threshold value set based on the fuel pressure, the fuel cell system 1B can be prevented from being erroneously controlled when the tank pressure sensor 43 fails. Become. As a result, since power generation is not continued due to a shortage of hydrogen, it is possible to prevent the deterioration (incorrect control) of the membrane (the anode and the cathode including the catalyst) of the fuel cell stack 10. Further, when it is determined that the tank pressure sensor 43 is out of order, the power generation is stopped, so that the power generation is continued without accurately grasping the remaining hydrogen amount, thereby preventing the deterioration of the membrane. be able to.

(Third embodiment)
FIG. 6 is a flowchart of the third embodiment showing the failure determination control of the tank pressure sensor. The fuel cell system in the third embodiment is the same as the fuel cell system 1A in the first embodiment shown in FIG. In the third embodiment, the ECU 41 includes a temperature change amount detection unit in addition to the fuel consumption calculation unit, the pressure threshold setting unit, and the failure determination unit.

  First, in step S301, when the ignition is turned on and power generation is started or during power generation, the ECU 41 resets the hydrogen consumption stored in the memory or the like, and detects the inside of the hydrogen tank 21 detected by the tank pressure sensor 43. The tank internal pressure P1 is detected, the tank internal temperature T1 in the hydrogen tank 21 detected by the tank internal temperature sensor 42 is detected, and each is stored. The tank internal pressure and the tank internal temperature detected when the hydrogen consumption is reset are defined as an initial tank internal pressure P1 and an initial tank temperature T1.

  In step S302, the ECU 41 determines whether or not the hydrogen consumption amount exceeds a predetermined value 1. This step S302 is the same as step S102 in the first embodiment. In step S302, when the ECU 41 determines that the hydrogen consumption is less than or equal to the predetermined value 1 (No), the ECU 41 repeats step S302, and when it is determined that the hydrogen consumption exceeds the predetermined value 1 (Yes). Then, it is determined that a predetermined amount of hydrogen has been consumed, and the process proceeds to step S303.

  In step S303, the ECU 41 sets a predetermined value 2 (pressure threshold) corresponding to the pressure corresponding to the hydrogen consumption (predetermined value 1). The predetermined value 2 is set by a map, a table, a function or the like. Note that step S303 corresponds to the processing performed by the pressure threshold value setting unit in the present embodiment.

  In step S304, the ECU 41 detects the tank internal pressure P2 in the hydrogen tank 21 detected by the tank internal pressure sensor 43 and the tank internal temperature sensor 42 when the hydrogen consumption exceeds a predetermined value 1. The tank temperature T2 in the hydrogen tank 21 to be detected is detected and stored.

  In step S305, the ECU 41 determines whether or not a pressure difference (P1-P2) obtained by subtracting the tank internal pressure P2 detected in step S304 from the initial tank internal pressure P1 detected in step S301 is smaller than a predetermined value 2. Judging. The predetermined value 2 is set in the same manner as in the first embodiment. This step S305 corresponds to the process performed by the failure determination means in this embodiment. In step S305, when the ECU 41 determines that the detected pressure difference (P1-P2) is equal to or larger than the predetermined value 2 (No), the ECU 41 returns to step S301, and the detected pressure difference (P1-P2) is the predetermined value. If it is determined that it is smaller than 2 (Yes), the process proceeds to step S306.

  In step S306, the ECU 41 determines whether or not a detected temperature change amount (T2-T1) obtained by subtracting the initial tank temperature T1 detected in step S301 from the tank temperature T2 detected in step S304 is smaller than a predetermined value 5. Judging. The predetermined value 5 is a value that is arbitrarily set in advance, and is set to 10 ° C., for example. This step S306 corresponds to the processing performed by the temperature change amount detection means in the present embodiment. In step S306, when the ECU 41 determines that the detected temperature change amount (T2-T1) is smaller than the predetermined value 5 (Yes), the ECU 41 proceeds to step S307 and determines that the tank pressure sensor 43 has failed. To do. Further, when the ECU 41 determines that the detected temperature change amount (T2-T1) is equal to or greater than the predetermined value 5 (No), the ECU 41 determines that the temperature change amount is too large and greatly affects the pressure fluctuation, and proceeds to step S301. Return.

  As described above, the fuel cell system according to the third embodiment can obtain the same effects as those of the first embodiment. Furthermore, in the third embodiment, when the amount of temperature change is extremely large, the pressure in the hydrogen tank 21 fluctuates greatly, making it difficult to accurately detect the pressure. Therefore, it is possible to prevent erroneous detection of a failure by determining whether or not to perform failure detection of the tank pressure sensor 43 based on the temperature change amount.

(Fourth embodiment)
FIG. 7 is a flowchart of the fourth embodiment showing the failure determination control of the tank internal pressure sensor. The fuel cell system in the fourth embodiment is the same as the fuel cell system 1B in the second embodiment shown in FIG. Further, steps S402 to S406 in FIG. 7 are the same as steps S202 to S206 in FIG.

  As shown in FIG. 7, in step S 401, the ECU 41 resets the accumulated current amount stored in the memory or the like, and detects the tank internal pressure (initial tank internal pressure) in the hydrogen tank 21 detected by the tank internal pressure sensor 43. Pressure) P1 is detected, and the tank temperature (initial tank temperature) T1 in the hydrogen tank 21 detected by the tank temperature sensor 42 is detected and stored. And the process of step S402-S406 is performed similarly to 2nd Embodiment.

  In step S406, if the ECU 41 determines that the tank pressure sensor 43 has failed, the ECU 41 proceeds to step S407, and calculates the amount of remaining hydrogen in the hydrogen tank 21. The amount of alternative residual hydrogen (alternative fuel gas amount) at this time is obtained by calculating the accumulated current amount from the initial residual hydrogen amount in the hydrogen tank 21 calculated based on the initial tank internal temperature T1 and the initial tank internal pressure P1 in step S401. It is calculated by subtracting the amount of hydrogen consumed by power generation (fuel consumption) from the reset (S401) and the amount of hydrogen discharged by the purge process (fuel consumption). After the processing of step 407 is completed, power generation is continued based on the calculated amount of alternative hydrogen remaining.

  Note that, immediately after the ignition is turned on and power generation is started, the hydrogen consumption by the power generation and the hydrogen consumption by the purge process include the hydrogen consumption at the time of OCV (Open Circuit Voltage) check at the time of ignition on. Amount included. This OCV check is a procedure necessary to determine whether or not the fuel cell stack 10 can generate power before generating power. For example, the open circuit voltage (also referred to as open-circuit voltage) of the fuel cell stack 10 is determined. Use to judge. The processing procedure at that time is performed by replacing the pipes 26a to 26e of the anode system 20 with hydrogen while the purge valve 25 is opened.

  As described above, in the fuel cell system according to the fourth embodiment, even when it is determined that the tank pressure sensor 43 is out of order, the alternative residual hydrogen amount is calculated. Therefore, the fuel cell system without stopping the power generation of the fuel cell stack 10. It becomes possible to continue driving.

(Fifth embodiment)
FIG. 8 is a flowchart of the fifth embodiment showing the failure determination control of the tank pressure sensor, and FIG. 9 is a map showing the relationship between the hydrogen consumption and the estimated pressure change amount. The fuel cell system in the fifth embodiment is the same as the fuel cell system 1A in the first embodiment shown in FIG. In the fifth embodiment, the ECU 41 includes fuel consumption calculation means, pressure estimation means, and failure determination means.

  As shown in FIG. 8, in step S <b> 502, the ECU 41 determines whether the hydrogen consumption calculated based on the flow rate (integrated flow rate) obtained from the flow rate sensor 44 exceeds a predetermined value 1. The predetermined value 1 is a value that is arbitrarily determined in advance. Further, this step S502 corresponds to the processing executed by the fuel consumption amount calculation means in the present embodiment. In step S502, when the ECU 41 determines that the hydrogen consumption is equal to or less than the predetermined value 1 (No), the ECU 41 repeats step S502 until the hydrogen consumption exceeds the predetermined value 1, and the hydrogen consumption reaches the predetermined value 1. If it is determined that it has exceeded (Yes), it is determined that a predetermined amount of hydrogen has been consumed, and the process proceeds to step S503.

  In step S503, the ECU 41 estimates the reduced pressure change amount ΔP in the hydrogen tank 21 based on the hydrogen consumption (predetermined value 1). The estimated pressure change amount ΔP at this time is set based on, for example, a map as shown in FIG. The map is not limited to the map, and may be set using a function or a table. Note that step S503 corresponds to the processing performed by the pressure estimation unit in the present embodiment.

  In step S504, the ECU 41 detects and stores the tank pressure P2 in the hydrogen tank 21 detected by the tank pressure sensor 43 when the hydrogen consumption exceeds a predetermined value 1.

  In step S505, the ECU 41 subtracts the tank internal pressure P2 detected in step S504 from the initial tank internal pressure P1 detected in step S501 (hereinafter referred to as a detected pressure change amount), and a step. It is determined whether or not the absolute value of the difference from the pressure change amount ΔP (estimated pressure change amount) estimated in S503 is greater than a predetermined value 6. The predetermined value 6 is a value that is arbitrarily set in advance. For example, the predetermined value 6 is set to a value that includes an allowable error capable of determining a failure of the tank pressure sensor 43. Further, this step S505 corresponds to the processing performed by the failure determination means of this embodiment.

  In step S505, if the ECU 41 determines that the difference between the detected pressure change amount (P1−P2) and the estimated pressure change amount (ΔP) is larger than the predetermined value 2 (Yes), the ECU 41 determines the pressure to determine the failure. It is determined that the difference is too large, and the process proceeds to step S506, where it is determined that the tank pressure sensor 43 has failed. In step S505, if the ECU 41 determines that the difference between the detected pressure change amount (P1-P2) and the estimated pressure change amount (ΔP) is equal to or less than the predetermined value 2 (No), the pressure difference is allowed. It is determined that it is within the range, that is, it is determined that the tank pressure sensor 43 is normal, and the process returns to step S501. Steps S506 and S507 are the same as steps S106 and S107 in the first embodiment.

  Thus, in the fuel cell system of the fifth embodiment, during power generation, the pressure (detected pressure change amount) detected by the tank pressure sensor 43 and the pressure estimated based on the hydrogen consumption (estimated pressure change amount). ), The failure detection of the tank pressure sensor 43 can be detected, and therefore it is possible to prevent erroneous control by the fuel cell system 1A when the tank pressure sensor 43 fails. For example, even in the case of a malfunction that erroneously detects that more hydrogen is left in the hydrogen tank 21 than in actuality, the malfunction of the tank pressure sensor 43 can be detected, so that power generation is not continued due to insufficient hydrogen. Further, it is possible to prevent erroneous control such that deterioration of the fuel cell stack 10, particularly the membrane (anode and cathode including the catalyst) progresses.

  Further, in the fuel cell system of the fifth embodiment, when it is determined that the tank pressure sensor 43 has failed, the power generation is stopped, so that the power generation continues without being able to accurately grasp the remaining hydrogen amount. As a result, it is possible to prevent film deterioration from being promoted.

  In the fifth embodiment described above, the failure determination is performed based on the difference between the detected pressure change amount (P1−P2) and the estimated pressure change amount (ΔP). However, the present invention is not limited to this. The current pressure (P1−ΔP) when the estimated pressure change amount (ΔP) estimated from the fuel consumption is subtracted from the initial tank pressure (P1) detected by the tank pressure sensor 43, and the tank pressure The failure may be determined based on the difference ((P1−ΔP) −P2> predetermined value 2) from the current pressure (P2) detected from the sensor 43.

In the first to fourth embodiments, the failure determination may be performed based on the detected pressure change amount and the estimated pressure change amount in the fifth embodiment. Moreover, you may apply the process (S407) of alternative hydrogen amount calculation of 4th Embodiment to 1st Embodiment-3rd Embodiment and 5th Embodiment.

It is a whole lineblock diagram showing the fuel cell system of a 1st embodiment. It is a flowchart which shows failure determination control of the tank internal pressure sensor in 1st Embodiment. 3 is a map showing a relationship between a predetermined value 1 and a predetermined value 2. It is a whole block diagram which shows the fuel cell system of 2nd Embodiment. It is a flowchart which shows failure determination control of the tank internal pressure sensor in 2nd Embodiment. It is a flowchart which shows the failure determination control of the tank internal pressure sensor in 3rd Embodiment. It is a flowchart which shows failure determination control of the tank internal pressure sensor in 4th Embodiment. It is a flowchart which shows the failure determination control of the tank internal pressure sensor in 5th Embodiment. It is a map which shows the relationship between hydrogen consumption and the estimated pressure change amount.

Explanation of symbols

1 Fuel Cell System 10 Fuel Cell Stack 21 Hydrogen Tank 41 ECU
42 Tank temperature sensor (container temperature detection means)
43 In-tank pressure sensor (in-container pressure detection means)
44 Flow sensor 45 Current sensor

Claims (5)

A fuel cell stack that is supplied with fuel gas and oxidant gas to generate power; and
A fuel gas storage container for storing fuel gas supplied to the fuel cell stack;
In-container pressure detection means for detecting the pressure in the fuel gas storage container;
An in-container temperature detecting means for detecting the temperature in the fuel gas storage container,
A fuel cell that estimates an amount of remaining fuel gas in the fuel gas storage container based on the pressure and temperature in the fuel gas storage container and controls operation of the fuel cell stack based on the amount of remaining fuel gas In the system,
Fuel consumption calculation means for calculating the fuel consumption of the fuel gas;
Pressure threshold value setting means for setting a pressure threshold value corresponding to the pressure corresponding to the fuel consumption amount calculated by the fuel consumption amount calculation means;
A failure determination means for determining a failure of the internal pressure detection means based on the pressure detected by the internal pressure detection means and the pressure threshold set by the pressure threshold setting means;
A fuel cell system comprising: A fuel cell stack that is supplied with fuel gas and oxidant gas to generate power; and
A fuel gas storage container for storing fuel gas supplied to the fuel cell stack;
In-container pressure detection means for detecting the pressure in the fuel gas storage container;
An in-container temperature detecting means for detecting the temperature in the fuel gas storage container,
A fuel cell that estimates an amount of remaining fuel gas in the fuel gas storage container based on the pressure and temperature in the fuel gas storage container and controls operation of the fuel cell stack based on the amount of remaining fuel gas In the system,
Fuel consumption calculation means for calculating the fuel consumption of the fuel gas;
Pressure estimating means for estimating the pressure in the fuel gas storage container based on the fuel consumption calculated by the fuel consumption calculating means;
A failure determination unit that determines a failure of the internal pressure detection unit based on the pressure detected by the internal pressure detection unit and the pressure estimated by the pressure estimation unit;
A fuel cell system comprising: A temperature change amount detecting means for detecting a temperature change amount in the fuel gas storage container;
3. The fuel cell according to claim 1, wherein the failure determination unit determines whether or not to perform a failure determination based on a temperature change amount detected by the temperature change amount detection unit. system.   4. The fuel cell system according to claim 1, wherein power generation of the fuel cell stack is stopped when the failure determination unit determines that a failure has occurred. 5.   When it is determined that the failure is determined by the failure determination unit, the amount of fuel consumed by the power generation of the fuel cell stack from the amount of fuel gas in the fuel gas storage container calculated before the failure determination by the failure determination unit and The fuel cell system according to any one of claims 1 to 3, wherein an alternative remaining fuel gas amount is calculated by subtracting a fuel consumption amount discharged by the purge process.

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