JP2007026843A - Fuel cell powered vehicle and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell powered vehicle and its control method applicable to a vehicle provided with an idling stop function, and capable of stabilizing power generation performance after returning from an idle stop. <P>SOLUTION: A specified value is added to an idle stop period (S2) when a conditions of idle stop is satisfied (S1, Yes), and a setting to increase purge frequency is performed (S5) when the idle stop period passes the specified value 1 (S4, Yes). Purge processing increasing purge frequency for a prescribed period after return is performed (S22) when it returns from the idle stop (S1, No). The frequency of the purge processing is returned to normal and the purge processing is performed at the ordinary purge frequency (S22) when the idle stop period becomes less than a specified value 2 (S6, Yes). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell moving body equipped with an idle stop function and a control method thereof.

Conventionally, in order to prevent wasteful use of hydrogen (fuel gas), a fuel cell vehicle has been provided with a circulation device for circulating unreacted hydrogen discharged from the fuel cell back to the fuel cell. Yes. For this reason, it is known that if power generation is continued, impurities such as nitrogen in the air permeate from the cathode electrode through the electrolyte membrane into the anode (fuel electrode) of the fuel cell, resulting in a decrease in power generation performance. It has been. Therefore, in order to prevent such a decrease in power generation performance, a fuel cell vehicle is provided with a control valve called a purge valve for discharging impurities such as nitrogen accumulated in the anode electrode. As a technique for controlling the purge valve, a technique that is performed based on a decrease in the cell voltage of the fuel cell or a technique that is performed based on the accumulated amount of nitrogen has been proposed (for example, Patent Document 1 and Patent Document 2). reference).
Japanese Patent Laying-Open No. 2003-173807 (Claim 1, FIG. 3) JP 2004-349068 (paragraph 0018, FIG. 1 and FIG. 2)

  In recent years, vehicles powered by gasoline or light oil have been parked to reduce emissions of substances that cause global warming, such as carbon dioxide, and air pollutants, and to prevent waste of noise and energy. It is recommended to stop the engine at an idling stop, but a technology equipped with an idling stop function has also been proposed for fuel cell vehicles.

  However, the techniques for controlling the purge valve described in Patent Document 1 and Patent Document 2 are both techniques for controlling the purge valve during power generation of the fuel cell, and are there any techniques for controlling the purge valve during idling stop. Not considered. For this reason, for example, when the idle stop time is extended for a long time, it is expected that a large amount of impurities such as nitrogen is accumulated in the anode electrode, so that the power generation performance after returning from the idle stop is poor. There is a problem of becoming stable.

  The present invention solves the above-described conventional problems, and is a fuel cell moving body that can be applied to a vehicle having an idle stop function and can stabilize power generation performance after returning from an idle stop, and a control method thereof. The purpose is to provide.

  The fuel cell moving body of the present invention includes a fuel cell that generates electricity by chemically reacting a fuel gas and an oxidant, and a gas that circulates the unreacted fuel gas discharged from the fuel cell back to the fuel cell. A circulation means; a purge valve for discharging the fuel gas supplied to the fuel cell to the outside; an idle stop means for idly stopping the fuel cell when an idle stop condition is satisfied; and an idle stop period of the fuel cell An idle stop period grasping means for calculating the fuel gas concentration recovery means for performing a recovery process of the concentration of the fuel gas supplied to the fuel cell based on the idle stop period.

  According to the present invention, by predicting the fuel gas concentration based on the idle stop period, the fuel gas concentration can be reliably recovered even when the idle gas stop period is extended for a long time and the fuel gas concentration is decreased. It becomes possible.

  Further, the apparatus further comprises an idle return determination means for determining return from the idle stop, and when the idle return determination means determines that the fuel gas concentration recovery means has returned from the idle stop, the fuel gas concentration recovery means It is possible to adopt a configuration for performing a concentration recovery process. According to this configuration, it is possible to reliably determine the return from the idle stop, and thus it is possible to prevent the process for recovering the fuel gas concentration before the return from being performed wastefully.

  For example, the fuel gas concentration recovery means increases the purge frequency over a predetermined period after returning from the idling stop as compared with the normal operation. Thereby, even if it is a return from a long idle stop period, the fuel gas concentration can be reliably recovered.

  In this case, the purge frequency may be variable according to the idle stop period. This allows finer control of the purge process.

  The fuel gas concentration recovery means may set at least a first purge time longer than a later purge time than during normal operation. Thereby, even if it is a return from a long idle stop period, the fuel gas concentration can be reliably recovered.

  The method for controlling a fuel cell moving body of the present invention includes a fuel cell that generates electricity by chemically reacting a fuel gas and an oxidant, and the unreacted fuel gas discharged from the fuel cell is returned to the fuel cell again. A gas circulation means for returning to the fuel cell, a purge valve for discharging the fuel gas supplied to the fuel cell to the outside, and a control means, and the fuel cell is idled when the vehicle is in a predetermined state. A control method for a fuel cell moving body, wherein the control means detects an idle stop period after the fuel cell stops power generation, and the concentration of the fuel gas of the fuel cell based on the idle stop period It is characterized by performing a process for recovering.

  According to the present invention, by predicting the fuel gas concentration based on the idle stop period, the fuel gas concentration can be reliably recovered even when the idle gas stop period is extended for a long time and the fuel gas concentration is decreased. It becomes possible.

  In addition, after the control means detects the return from the idle stop, the fuel gas concentration of the fuel cell can be recovered. As a result, it is possible to reliably determine the return from the idle stop, and thus it is possible to prevent the process for recovering the fuel gas concentration before the return from being performed wastefully.

  For example, the control means may perform a process of recovering the concentration of the fuel gas by increasing the purge frequency for a predetermined period after returning from the idle stop, compared with the normal operation. Thereby, even if it is a return from a long idle stop period, the fuel gas concentration can be reliably recovered.

  In this case, the control means may change the purge frequency according to the idle stop period. This allows finer control of the purge process.

  Further, the control means may perform a process of recovering the concentration of the fuel gas by making at least the first purge time longer than the purge time after the normal operation. Thereby, even if it is a return from a long idle stop period, the fuel gas concentration can be reliably recovered.

  According to the present invention, power generation performance after returning from idle stop can be stabilized even when the idle stop period is long.

  FIG. 1 is a diagram showing a power system of a fuel cell vehicle according to the present embodiment, FIG. 2 is a configuration diagram showing a fuel cell system mounted on the fuel cell vehicle, and FIG. 3A is a flowchart showing a purge frequency setting process. FIG. 4 is a flowchart showing the purge execution availability process, FIG. 4 is a graph showing the relationship between the idle stop period and the purge frequency, and FIG. 5 is a time chart showing the purge process after returning from the idle stop. Is a purge process based on the graph of Example 1 of FIG. 4, (b) is a purge process based on the graph of Example 2 of FIG. 4, and (c) is a time chart showing a purge process based on the normal graph of FIG. is there.

  As shown in FIG. 1, the fuel cell vehicle V of the present embodiment includes a vehicle 1 including a fuel cell system F1, a power storage device 20, a controller 21, a travel motor 22, and the like.

  As shown in FIG. 2, the fuel cell system F1 includes a fuel cell FC, a hydrogen supply unit 2, an air supply unit 3, a gas circulation unit 4, a purge valve 5, a control unit 10, and the like.

  The fuel cell FC has a membrane electrode structure in which an anode electrode (hydrogen electrode) p1 including a catalyst is provided on one surface side of the solid polymer electrolyte membrane m and a cathode electrode (oxygen electrode) p2 including a catalyst is provided on the other surface side ( A plurality of single cells each having a conductive separator (not shown) on both sides of an MEA (Mebrane Electrode Assembly) are laminated in the thickness direction. The separator facing the anode electrode is formed with a flow path through which hydrogen as a fuel gas flows, and the separator facing the cathode electrode is formed with a flow path through which air (oxygen) as an oxidant flows. Yes. Further, the separator is formed with a flow path through which a refrigerant for cooling the fuel cell FC flows.

  The hydrogen supply means 2 supplies hydrogen to the anode electrode p1 of the fuel cell FC, and an anode gas pipe 2c is connected to the upstream side (inlet side) of the anode electrode p1 of the fuel cell FC. A high-pressure hydrogen tank 2a having a shutoff valve 2b is connected to the most upstream side of 2c. Although not shown, the hydrogen supply means 2 is provided with a regulator for adjusting the pressure of the high-pressure hydrogen discharged from the high-pressure hydrogen tank 2a on the downstream side of the shutoff valve 2b. Further, an anode offgas pipe 2d is connected to the downstream side (outlet side) of the anode electrode p1 of the fuel cell FC, and a purge valve 5 described later is provided in the anode offgas pipe 2d.

  The air supply means 3 supplies air (oxygen) as an oxidant to the cathode electrode p2 of the fuel cell FC, and the cathode gas pipe 3b on the upstream side (inlet side) of the cathode electrode p2 of the fuel cell FC. And the compressor 3a is connected to the most upstream side of the cathode gas pipe 3b. Further, although not shown, the air supply means 3 is provided with a cooling device (not shown) for cooling the compressed air from the compressor 3a to the cathode gas pipe 3b on the downstream side of the compressor 3a. A humidifier (not shown) for humidifying the air to a humidity suitable for the reaction is provided. Further, a cathode offgas pipe 3c is connected to the downstream side (exit side) of the cathode electrode p2 of the fuel cell FC, and the cathode offgas pipe 3c communicates with the anode offgas pipe 2d to the outside of the vehicle 1.

  The gas circulation means 4 includes an ejector 4a and a circulation gas pipe 4b. The ejector 4a is located on the inlet side of the anode electrode p1 of the fuel cell FC, and one end of the circulation gas pipe 4b is connected to the anode off-gas pipe 2d. The other end is connected to the ejector 4a. In the ejector 4a, unreacted hydrogen discharged from the fuel cell FC is sucked and circulated through the circulation gas pipe 4b using the flow of hydrogen supplied from the high-pressure hydrogen tank 2a to the fuel cell FC. Is possible.

  The control unit 10 includes a CPU (Central Processing Unit), a memory, an input / output interface, and the like. The control unit 10 has a function of idlingly stopping the fuel cell FC (idle stopping means), and a function of calculating an idle stop period after idling is stopped (idle (Stop period grasping means), a function of recovering the hydrogen concentration of the anode p1 of the fuel cell FC (fuel gas concentration recovery means), and a function of determining return from idling stop (idle return determination means). The control unit 10 is electrically connected to the shutoff valve 2b, the purge valve 5, and the compressor 3a so that the opening / closing operation of the shutoff valve 2b and the purge valve 5 and the rotational output of the motor provided in the compressor 3a can be controlled. It has become. Note that the idle stop of the fuel cell FC means that the power supply to the auxiliary devices of the fuel cell FC such as the compressor 3a is stopped.

  As shown in FIG. 1, the power storage device 20 mounted on the vehicle 1 can store electricity generated by the fuel cell FC, and includes a battery or a capacitor. For example, the battery is a lead storage battery, a lithium ion secondary battery, a lithium polymer secondary battery, a nickel hydride storage battery, a nickel cadmium storage battery, or the like, and the capacitor is an electric double layer capacitor or an electrolytic capacitor.

  The controller 21 includes a DC / DC converter, an inverter, and the like. The DC / DC converter controls the current output from the fuel cell FC based on the current command value output from the control unit 10 (see FIG. 2), that is, the power generation command for the fuel cell FC. Further, the inverter converts DC power output from the fuel cell FC and the power storage device 20 into AC power based on a torque command output from the control unit 10 (see FIG. 2), and this AC power is converted to the traveling motor 22. To supply.

  The traveling motor 22 is, for example, a permanent magnet type three-phase AC synchronous motor, and rotates the drive wheels W (see FIG. 1) with electric power supplied from the fuel cell FC and / or the power storage device 20.

Next, the operation of the fuel cell vehicle according to the present embodiment will be described with reference to the flowcharts of FIGS.
First, when the fuel cell vehicle V is operating normally, hydrogen (H ₂ ) and air (Air) are supplied to the fuel cell FC, so that hydrogen and oxygen contained in the air undergo an electrochemical reaction. Power is generated by This electric power is supplied to the traveling motor 22 and auxiliary machines such as the compressor 3a, and is stored in the power storage device 20 as necessary. In addition, when the vehicle 1 suddenly accelerates and the electric power from the fuel cell FC is insufficient, electric power is supplied from both the fuel cell FC and the power storage device 20 to the traveling motor 22 and the like. In the fuel cell vehicle V, when the ignition switch is on, the purge process is repeatedly executed at a predetermined interval (normal purge frequency) regardless of whether the vehicle is running or stopped.

  For example, when the fuel cell vehicle V temporarily stops waiting for a signal, the fuel cell vehicle V is in an idle stop condition in step (hereinafter abbreviated as “S”) 1 in FIG. It is determined whether or not the above is satisfied. The idle stop condition is, for example, when the brake pedal is depressed (BKSW-ON), the vehicle 1 is stopped (vehicle speed is zero; VS = 0), and the accelerator is OFF (θth = 0). If it is determined in S1 that the conditions for idling stop are satisfied (Yes), the power supply to the compressor 3a is stopped or the power supply to the compressor 3a is stopped and the shutoff valve 2b is closed to Stop power generation with battery FC. However, electric power to other necessary auxiliary machines is supplied from the power storage device 20.

  While the fuel cell FC is idling, if the compressor 3a, which consumes a relatively large amount of power, is driven with the same output as the normal operation, even though a large amount of power is not required, the power is wasted. For this reason, by stopping the power supply to the compressor 3a when the condition for idling stop is satisfied, it is possible to prevent wasteful consumption of hydrogen and decrease in power generation efficiency.

  The case where the fuel cell vehicle V satisfies the conditions for idling stop is not limited to the state described above, and may be when the vehicle is traveling in a cruise mode on a highway or the like. Also in this case, the power generation in the fuel cell FC can be stopped and the vehicle can be driven with the electric power from only the power storage device 20.

  If the idle stop condition is satisfied in S1 (Yes), a predetermined value is added to the idle stop period (S2). For example, if the idle stop period is t, in S2, the idle stop period is incremented (added) as t = t + 1. If the idle stop period is just after the start, the idle stop period is zero, and the process of S2 is repeated by repeatedly executing the flowchart of FIG. It will increase. Then, it is determined whether or not the idle stop period to which the predetermined value is added exceeds the predetermined value 1 (S4). Immediately after the start of the idle stop, the idle stop period is less than the predetermined value 1 (No), and the process proceeds to S6. In S6, it is determined whether the idle stop period is less than a predetermined value 2. Immediately after the start of the idle stop, the idle stop period is less than the predetermined value 2 (Yes), and the process proceeds to S7. In S4, the fact that the idle stop period is determined to be equal to or less than the predetermined value 1 means that the idle stop period is short and the accumulated amount of nitrogen that has permeated the solid polymer electrolyte membrane m on the anode p1 side of the fuel cell FC. Therefore, the purge frequency is set to normal (S7).

  On the other hand, the process shown in FIG. 3B is executed in parallel with the process shown in FIG. 3A, and it is determined in S21 whether power generation is in progress. Since the conditions for idling stop are satisfied in the above description, it is determined that power generation is not in progress (No), and the purge process is not executed.

  Thus, immediately after the start of the idle stop, the process (S1 → S2 → S4 → S6 → S7) shown in FIG. 3A and the process (S21) shown in FIG. 3B are repeated. Thereafter, by repeating such processing, the value set in the idle stop period increases, so that it is determined in S4 that the idle stop period has exceeded the predetermined value 1 (Yes). That is, since it can be determined that a large amount of nitrogen has accumulated in the anode electrode p1 of the fuel cell FC after a long time has elapsed since the idling stop, a setting for increasing the purge frequency is performed in S5. In this case as well, the purge stop process is not executed in the process of FIG. 3B because the idle stop condition is still satisfied as described above.

  After that, when returning from the idle stop and the idle stop condition is not satisfied and the power generation of the fuel cell FC is resumed (S1, No), a predetermined value is subtracted from the idle stop period in S3. For example, in S3, the idle stop period is decremented (subtracted) with t = t-1. For example, if the fuel cell vehicle V resumes running from a stopped state, the power can be generated when the accelerator pedal of the fuel cell vehicle V is depressed (θth ≠ 0). You may make it raise the flag to the effect of being inside. In S4, immediately after the return from the idle stop, it is determined that the idle stop period has exceeded the predetermined value 1. Therefore, the process proceeds to S5, and the purge frequency setting remains unchanged.

  Then, if power generation is continued thereafter (S1, No), the flowchart of FIG. 3A is repeatedly executed, so the predetermined value set in the idle stop period gradually decreases (S3). In the determination at S4, the idle stop period is equal to or less than the predetermined value 1 (No). However, in the process of S6, since the idle stop period is still greater than or equal to the predetermined value 2 (No), the purge frequency setting is not changed, that is, the increase setting is kept. In this case, since it is determined in S21 that power generation is in progress (Yes), the process proceeds to S22, and the purge frequency set in the process of FIG. Execute the process.

  In this purge process, the purge valve 5 is opened, hydrogen is supplied from the high-pressure hydrogen tank 2a, and impurities such as nitrogen are discharged downstream of the purge valve 5 together with hydrogen. Hydrogen containing nitrogen or the like discharged from the purge valve 5 is diluted to a predetermined hydrogen concentration with air or water discharged from the cathode electrode p2 side of the fuel cell FC via a diluter (not shown), and then the vehicle 1 It is discharged outside.

  If the power generation of the fuel cell FC is further continued, it is determined that the predetermined value set in the idle stop period in S3 is further reduced and the idle stop period is smaller than the predetermined value 2 (S6, Yes). Then, the purge frequency is returned to the normal setting (S7). At this time, since it is determined that power is being generated (S21, Yes), the purge process is executed with the purge frequency set in the process of FIG. 3A, that is, the normal purge frequency is set.

  In the embodiment described above, as shown in Example 1 in FIG. 4, when the idle stop period exceeds t1 (predetermined value 1), processing for setting the purge frequency to be increased is performed. That is, as shown in FIG. 5C, when the power generation is resumed from what was executed at the normal purge frequency, the purge frequency is set to be increased as shown in FIG. 5A. The purge process is executed for a predetermined period. After a predetermined period, the purge frequency is returned to the normal purge frequency, and the normal purge process is performed.

  Thus, by increasing the purge frequency after returning from idle stop, even if the idle stop period extends for a long time, the hydrogen concentration of the anode electrode p1 can be reliably recovered, and the power generation performance after return Can be stabilized.

  Further, as shown in the diagram of the second embodiment of FIG. 4, the frequency of the purge process may be variable based on the length of the idle stop period. When the idle stop period t2 is longer than that in the first embodiment, as shown in FIG. 5B, the frequency of the purge process can be increased as compared with the first embodiment in FIG. Although not shown, when the idle stop period is shorter than t1, the frequency of the purge process can be reduced as compared with the first embodiment. In this way, by changing the purge frequency based on the length of the idle stop period, it is possible to perform a finer hydrogen concentration recovery process. That is, when the idle stop period becomes long, the purge frequency can be increased to reliably recover the hydrogen concentration of the anode electrode p1, and when the idle stop period is short, the purge frequency is decreased. Therefore, it is possible to prevent the purge process from being performed wastefully.

  Incidentally, as shown in FIG. 8, it is known that the amount of nitrogen permeating from the cathode electrode p2 to the anode electrode p1 in the membrane (MEA) increases as the humidity increases. The reason why the nitrogen permeation amount increases in this way is that the film polymer swells as the film humidity increases, and the gap between the anode electrode p1 and the cathode electrode p2 increases. Therefore, considering this point, the purge frequency may be corrected based on the following processing. FIG. 6 is a flowchart showing the purge frequency correction process, FIG. 7A is a map showing the relationship between the idle stop period and the purge frequency, and FIG. 6B is a map showing the relationship between the anode outlet gas temperature and the MEA water content. (C) is a map showing the relationship between the cathode outlet gas temperature and the MEA water content, and (d) is a map showing the relationship between the MEA water content and the correction coefficient.

  As shown in FIG. 6, the purge frequency A is first calculated from the idle stop period based on the map of FIG. 7A (S100). The purge frequency A is quantified based on the idle stop period.

  Then, the MEA water content B is calculated from the gas temperature discharged from the outlet of the anode p1 side of the fuel cell FC based on the map of FIG. 7B (S101), and discharged from the cathode p2 side. The MEA water content C is calculated from the gas temperature based on the map shown in FIG. 7C (S102). The anode outlet gas temperature is determined by a temperature sensor (not shown) provided in the anode off-gas pipe 2d on the outlet side of the anode pole p1 of the fuel cell FC, and the cathode outlet gas temperature is changed to the cathode on the outlet side of the cathode pole p2. Each is detected by a temperature sensor (not shown) provided in the off-gas pipe 3c. Then, it is determined whether or not the water content B is greater than the water content C (S103). If the water content B is greater than the water content C (Yes), the water content B is set as the MEA water content. (S104) If the water content C is greater than or equal to the water content B (No), the water content C is set as the MEA water content (S105). That is, in the processing of S101 to S105, control is performed so that a value having a large water content is selected.

  Then, a purge frequency correction coefficient D is calculated from the MEA water content set in S104 or S105 based on the map of FIG. 7D (S106), and the purge frequency E = A × D The purge frequency E is calculated by adding the correction coefficient D to the purge frequency A (S107).

  Then, the normal purge frequency F is calculated (S108), and it is determined whether the purge frequency E is greater than the purge frequency F (S109). The purge frequency F is calculated based on the idle stop period from the same map as in FIG. When the purge frequency E is greater than the purge frequency F (S109, Yes), the purge frequency is set to E, that is, the purge frequency is set to increase (S110), and the purge frequency F is equal to or higher than the purge frequency E (S109, No), the purge frequency is set to F, that is, the purge frequency is set to normal (S111). That is, in the processing of S108 to S111, control is performed so that a value with a large purge frequency is selected.

  As described above, by correcting the purge frequency in consideration of the nitrogen permeation amount based on the humidity of the film, it is possible to control the purge process with higher accuracy.

  Next, another purge control in the fuel cell vehicle of this embodiment will be described with reference to FIGS. 9 and 10. FIG. 9A is a flowchart showing a purge frequency setting process, FIG. 9B is a flowchart showing another process for determining whether or not purge can be executed, and FIG. 10 is a time chart showing the purge process after returning from idle stop. ) Is a purge process in which the initial purge time is set long, and (b) is a time chart showing a normal purge process. FIG. 9 (a) is the same as FIG. 3 (a), and FIG. 9 (b) is provided with S23 to S26 instead of S22 of FIG. 3 (b). In the following description, the processing when the conditions for idling stop are satisfied is the same as in FIGS. 3A and 3B, and therefore the description thereof is omitted, and the setting for increasing the purge frequency is performed. The processing immediately after returning from the idle stop will be described.

  That is, when it is determined that the fuel cell FC is generating electricity (S21, Yes), it is determined in S23 whether or not it is the first purge. In this case, since it is immediately after returning from the idle stop, it is determined that the first purge is performed (S23, Yes), and a process for setting the first purge time to be increased is performed (S24). In S26, the purge process is executed based on the purge frequency set in the process of FIG. 9A, that is, the setting with the increased purge frequency.

  Similarly, after S1, S3, S4 and S5 in FIG. 9A and S21 in FIG. 9B, it is determined that the initial purge process is not performed in S23 (No, second time). Thereafter, a process of returning the purge time to the normal time is performed (S25), and the purge process is executed based on the purge frequency set in the process of FIG. 9A (S26). That is, as shown in the third embodiment of FIG. 10A, the purge process with an increased purge frequency is executed, but the purge time is lengthened only for the first purge process, and the purge is performed every second and subsequent times. Return time to normal. Further, when the power generation is continued thereafter and the value set in the idle stop period becomes smaller than the predetermined value 2, that is, when the predetermined period elapses, the purge frequency is the same as that in FIG. Return to normal purge frequency.

  Thus, by setting the first purge time longer than the second and subsequent times, it is possible to quickly recover the hydrogen concentration of the anode electrode p1 after returning from the idle stop, and the power generation performance can be stabilized.

  The present invention is not limited to the above-described embodiment, and the time of the first purge process in the normal purge process shown in FIG. 5C or FIG. 10B may be set longer. Good. In the above-described embodiment, the fuel cell moving body has been described by taking a vehicle as an example, but it can also be applied to a ship, an aircraft, or the like.

It is a figure which shows the electric power system of the fuel cell vehicle of this embodiment. It is a block diagram which shows the fuel cell system mounted in a fuel cell vehicle. (A) is a flowchart showing a purge frequency setting process, and (b) is a flowchart showing a purge execution enable / disable process. It is a graph which shows the relationship between an idle stop period and purge frequency. 5 is a time chart showing a purge process after returning from idle stop, where (a) is a purge process based on the graph of Example 1 in FIG. 4, (b) is a purge process based on the graph of Example 2 in FIG. c) is a purge process based on the normal graph of FIG. It is a flowchart which shows the correction process of purge frequency. (A) is a map showing the relationship between the idle stop period and the purge frequency, (b) is a map showing the relationship between the anode outlet gas temperature and the MEA water content, and (c) is the relationship between the cathode outlet gas temperature and the MEA water content. A map showing the relationship, (d) is a map showing the relationship between the MEA water content and the correction coefficient. It is a graph which shows the relationship between the humidity of a film | membrane, and nitrogen permeation amount. (A) is a flowchart showing a purge frequency setting process, and (b) is a flowchart showing another process for determining whether or not purge can be executed. It is a time chart which shows the purge process after return from idle stop, (a) is the purge process which set the first purge time long, (b) is a normal purge process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2a High pressure hydrogen tank 3a Compressor 4 Gas circulation means 5 Purge valve 10 Control part (idle stop means, idle stop period grasping means, fuel gas concentration recovery means, idle return determination means, control means)
20 Power Storage Device 22 Traveling Motor FC Fuel Cell V Fuel Cell Car (Fuel Cell Vehicle)

Claims (10)

A fuel cell that generates electricity by chemically reacting a fuel gas and an oxidant;
Gas circulation means for circulating the unreacted fuel gas discharged from the fuel cell back to the fuel cell;
A purge valve for discharging the fuel gas supplied to the fuel cell to the outside;
Idle stop means for idle-stopping the fuel cell when an idle stop condition is satisfied;
Idle stop period grasping means for calculating an idle stop period of the fuel cell;
Fuel gas concentration recovery means for performing recovery processing of the concentration of fuel gas supplied to the fuel cell based on the idle stop period;
A fuel cell moving body comprising:   Idle return determination means for determining return from idle stop is further provided, and when the idle return determination means determines that the engine has returned from idle stop, the fuel gas concentration recovery means determines the concentration of the fuel gas in the fuel cell. The fuel cell moving body according to claim 1, wherein a recovery process is performed.   3. The fuel cell moving body according to claim 2, wherein the fuel gas concentration recovery means increases the purge frequency over a predetermined period after returning from an idle stop as compared with normal operation.   The fuel cell moving body according to claim 3, wherein the purge frequency is variable according to the idle stop period.   The fuel cell according to any one of claims 1 to 4, wherein the fuel gas concentration recovery means sets at least a first purge time longer than a later purge time than during normal operation. Moving body. A fuel cell that generates electricity by chemically reacting a fuel gas and an oxidant, a gas circulation means for returning the unreacted fuel gas discharged from the fuel cell to the fuel cell again, and the fuel cell A control method for a fuel cell moving body, comprising a purge valve for discharging the fuel gas to the outside, and a control means, wherein the fuel cell is idle-stopped when an idle stop condition is satisfied,
The control means detects an idle stop period after the fuel cell stops power generation, and performs a process of recovering the concentration of the fuel gas in the fuel cell based on the idle stop period. Control method of fuel cell moving body.   7. The method of controlling a fuel cell moving body according to claim 6, wherein the control means performs processing for recovering the concentration of the fuel gas in the fuel cell after detecting return from idle stop.   8. The fuel according to claim 7, wherein the control means performs a process of recovering the concentration of the fuel gas by increasing the purge frequency for a predetermined period after returning from the idle stop, as compared with the normal operation. Control method of battery moving body.   9. The method of controlling a fuel cell moving body according to claim 8, wherein the control means changes the purge frequency according to the idle stop period.   The control means performs the process of recovering the concentration of the fuel gas by making at least the first purge time longer than the purge time after the normal operation. The method for controlling a fuel cell moving body according to any one of the above.

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