JP2004129433A - Fuel cell powered vehicle and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable restarting of a vehicle in a short time from an idling stop, while improving fuel consumption by stopping the feed of reactive gas to a fuel cell at idle stop. <P>SOLUTION: Air block mechanisms (shut valves 25, 26) for blocking an air pole passage in the idle stop are arranged at an air feed system of the fuel cell 2. Air is sealed in the air pole passage, while keeping the pressure of the air, by blocking the air pole passage with an air blocking mechanisms in the idle stop. When restarting, the rise in the air pressure necessary for reaching pressure required for extracting prescribed power does not need to be large, thus enabling restart within a short time. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel cell vehicle equipped with a fuel cell as a drive source and a control method thereof, and more particularly to an improvement in control technology at the time of idle stop.
[0002]
[Prior art]
2. Description of the Related Art Fuel cell technology that enables clean exhaust and high energy efficiency has attracted attention as a countermeasure against environmental problems in recent years, in particular, air pollution caused by exhaust gas from vehicles and global warming caused by carbon dioxide. 2. Description of the Related Art A fuel cell is an energy conversion system that supplies hydrogen or a hydrogen-rich reformed gas and air as a fuel to an electrolyte-electrode catalyst composite, causes an electrochemical reaction, and converts chemical energy into electric energy. Above all, solid polymer electrolyte fuel cells using solid polymer membranes as electrolytes are inexpensive, easy to make compact, and have a high power density, so they are expected to be used as driving sources for vehicles. ing.
[0003]
By the way, in a fuel cell vehicle equipped with the above-described fuel cell as a drive source, there is a problem in controlling the operation of the fuel cell at the time of idle stop in which the vehicle is temporarily stopped. If power is supplied from the fuel cell even at the time of idling stop, fuel efficiency deteriorates due to poor power generation efficiency in the low output region of the fuel cell.
[0004]
Accordingly, an idle control device has been developed that stops the supply of the reactant gas and stops the power generation of the fuel cell when it is detected that the fuel cell vehicle is in the idle stop state (for example, see Patent Document 1). . In the idle control device described in Patent Document 1, when the rotation speed of the motor driving the fuel cell vehicle is equal to or less than a predetermined value, the brake is on, the remaining battery charge is equal to or more than the predetermined charge, and the electric load is equal to or less than the predetermined value. In some cases, it is determined that the fuel cell is in an idle state, and the supply of air or hydrogen as a reaction gas is stopped to stop the power generation in the fuel cell.
[0005]
[Patent Document 1]
JP 2001-359204 A
[0006]
[Problems to be solved by the invention]
However, if the supply of the reaction gas is stopped at the time of idling stop as in the above-described prior art, the pressure of the reaction gas in the fuel cell gradually decreases, and there is a possibility that trouble may occur particularly at the time of restart. In general, as the power generated by the fuel cell increases, the supplied reaction gas needs to have a higher flow rate and a higher pressure. Therefore, when the supply of the reaction gas is stopped at the time of the idle stop as described above and the pressure of the reaction gas in the fuel cell decreases, the pressure required to take out the predetermined power at the time of next power generation is reduced. Time is required to increase the reaction gas pressure.
[0007]
Therefore, when it is necessary to restart the fuel cell in a short time after the idle stop, for example, when the fuel cell vehicle is temporarily stopped due to waiting for a traffic light, such a control method takes too much time to start up, and the control method takes too much time. Fast start-up, i.e., unable to respond to fast power draw requests. In particular, since the air electrode side of the fuel cell is configured to increase the air pressure by the compressor, a large amount of energy is consumed to compensate for the above-described pressure drop.
[0008]
The present invention has been proposed for the purpose of solving the above-mentioned problems of the prior art. That is, the present invention can improve fuel efficiency by stopping the supply of reactant gas at the time of idling stop, and at the time of restart, can extract desired electric power from the fuel cell in a short time, and a fuel cell vehicle. It is an object to provide a control method.
[0009]
[Means for Solving the Problems]
In the present invention, in order to achieve the above object, an air supply means and a hydrogen supply means, an air electrode passage for guiding air from the air supply means to an air electrode of a fuel cell stack, and a hydrogen supply means In a fuel cell vehicle in which a fuel cell including a hydrogen electrode passage for guiding hydrogen to a hydrogen electrode of a fuel cell stack is mounted as a driving source, an air shutoff mechanism is provided on an inlet side and an outlet side of an air electrode passage of the fuel cell. When the engine is idle, the air cutoff mechanism shuts off the air electrode passage of the fuel cell and maintains the pressure in the air electrode passage of the fuel cell.
[0010]
As described above, by closing the air in the air electrode passage of the fuel cell while maintaining the pressure at the time of idling stop, an increase in the air pressure to reach a pressure necessary for extracting predetermined power at the next start-up is prevented. Only a few are needed. Therefore, when the idle stop is released and power is again generated by the fuel cell, the time required for pressure increase can be greatly reduced, power generation by the fuel cell can be resumed in a short time, and energy consumption by the compressor is suppressed. You.
[0011]
【The invention's effect】
According to the present invention, since the supply of the reaction gas is stopped at the time of the idle stop, the fuel efficiency can be greatly improved.At the time of the idle stop, the air electrode passage of the fuel cell is shut off by the air shutoff mechanism. Since the pressure in the air electrode passage of the fuel cell is maintained, quick restart and quick power extraction are possible. Further, energy consumption by the compressor or the like at the time of restart can be suppressed.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a fuel cell vehicle to which the present invention is applied and a control method thereof will be described in detail with reference to the drawings.
[0013]
(1st Embodiment)
FIG. 1 shows a basic configuration of a fuel cell vehicle. The fuel cell vehicle has a vehicle body 1 on which a fuel cell power generation system (hereinafter, simply referred to as a fuel cell) 2 is mounted as a driving power source, and further includes an inverter 3, a driving motor 4, a driving wheel 5, a vehicle speed sensor. 6, a secondary battery 7, a relay 8, a controller 9, and the like.
[0014]
The fuel cell 2 controls the pressure and flow rate of hydrogen and air supplied to the fuel cell stack by using a pressure regulating valve, a compressor, and the like so that power consumed by the drive motor 4 and power required for charging the secondary battery 7 can be generated. It is controlled by. The inverter 3 converts the DC power generated by the fuel cell 2 into AC power, and controls the drive motor 4 so that the drive motor output torque is instructed by the controller 9.
[0015]
The drive wheel 5 is mechanically connected to the drive motor 4 and transmits the drive torque of the drive motor 4 to the tire to generate a drive force. Here, a vehicle speed sensor 6 is provided, and the rotation speed of the drive wheel 5 is detected by the vehicle speed sensor 6.
[0016]
The secondary battery 7 supplies electric power to the drive motor 4 when electric power is not supplied from the fuel cell 2 such as at idle stop. The relay 8 connects / disconnects the fuel cell 2 and the load circuit based on a command from the controller 9.
[0017]
Next, a specific configuration of the fuel cell 2 will be described with reference to FIG. As shown in FIG. 2, the fuel cell 2 includes a fuel cell stack 11, a hydrogen supply system for supplying hydrogen (or a hydrogen-rich gas) as fuel to the fuel cell stack 11, and an oxidant And an air supply system for supplying air.
[0018]
The fuel cell stack 11 is formed by stacking power generation cells in which a hydrogen electrode 11a to which hydrogen is supplied and an air electrode 11b to which oxygen (air) is supplied are stacked with an electrolyte / electrode catalyst composite interposed therebetween. There is a power generation unit that converts chemical energy into electric energy by an electrochemical reaction. At the hydrogen electrode 11a, when hydrogen is supplied, hydrogen is dissociated into hydrogen ions and electrons, the hydrogen ions pass through the electrolyte, and the electrons generate electric power through an external circuit and move to the air electrode 11b. At the air electrode 11b, oxygen in the supplied air reacts with the hydrogen ions and electrons to generate water, which is discharged to the outside.
[0019]
As the electrolyte of the fuel cell stack 11, for example, a solid polymer electrolyte is used in consideration of high energy density, low cost, light weight, and the like. The solid polymer electrolyte is an ion (proton) conductive polymer membrane such as a fluororesin-based ion exchange membrane, and functions as an ion conductive electrolyte when saturated with water.
[0020]
The hydrogen supply system guides the hydrogen from the hydrogen supply means to the hydrogen electrode 11a of the fuel cell stack 11 through the hydrogen electrode passage. That is, this hydrogen supply system has a high-pressure hydrogen tank 12 as a hydrogen supply means, a hydrogen pressure regulating valve 13, an ejector 14, a hydrogen supply pipe 15 serving as a hydrogen electrode passage, and a hydrogen circulation pipe 16. Further, a hydrogen pressure sensor 17 is provided near the inlet of the hydrogen electrode 11a of the fuel cell stack 11. Then, the hydrogen gas supplied from the high-pressure hydrogen tank 12 serving as the hydrogen supply source is sent to the hydrogen supply pipe 15 through the hydrogen pressure regulating valve 13 and the ejector 14 and supplied to the hydrogen electrode 11 a of the fuel cell stack 11. . At this time, the hydrogen pressure regulating valve 13 is controlled based on the output from the hydrogen pressure sensor 16 and is supplied so that the pressure in the hydrogen electrode 11a and the pressure in the hydrogen electrode passage of the fuel cell stack 11 becomes a pressure corresponding to the load. The hydrogen gas pressure is adjusted.
[0021]
In the fuel cell stack 11, not all of the supplied hydrogen gas is consumed. Unused hydrogen gas (hydrogen gas discharged from the fuel cell stack 11) passes through the hydrogen circulation pipe 17 and is ejected by the ejector 14. The fuel gas is circulated, mixed with newly supplied hydrogen gas, and supplied again to the fuel electrode 11 a of the fuel cell stack 11. Thereby, the stoichiometric ratio (supply flow rate / consumption flow rate) of hydrogen can be made 1 or more, and the cell voltage is stabilized.
[0022]
A purge valve 18 and a purge pipe 19 are provided on the outlet side of the fuel cell stack 11. The purge valve 18 is normally closed, and is opened when a decrease in cell voltage due to water clogging of the fuel cell stack 11 or accumulation of inert gas is detected. Impurities, nitrogen, and the like are accumulated in the hydrogen circulation pipe 17 by circulating the hydrogen gas, which may lower the hydrogen partial pressure and reduce the efficiency of the fuel cell 2 in some cases. Therefore, a purge valve 18 and a purge pipe 19 are provided on the outlet side of the fuel cell stack 11, and the purge valve 18 is opened as necessary to perform hydrogen purging, thereby removing impurities, nitrogen, and the like from the hydrogen circulation pipe 17. I can do it.
[0023]
The air supply system guides the air from the air supply means to the air electrode 11b of the fuel cell stack 11 through the air electrode passage. That is, this air supply system has a compressor 20 and an air pressure regulating valve 21 as air supply means, and an air supply pipe 22 as an air electrode passage. Here, the compressor 20 sends air to the air electrode 11b of the fuel cell stack 11, and supplies, for example, air compressed by driving a motor to the air electrode 11b of the fuel cell stack 11 through the air supply pipe 22. The air pressure regulating valve 21 regulates the pressure of the air supplied by the compressor 20, and is provided on the outlet side of the air electrode 11b of the fuel cell stack 11. Further, an air pressure sensor 23 is provided near the inlet of the air electrode 11b of the fuel cell stack 11, and the air pressure regulating valve 21 is controlled based on the output from the air pressure sensor 23. The pressure of the air supplied by the compressor 20 is adjusted so that the pressure in the air electrode 11b and the air electrode passage becomes a pressure corresponding to the load. Note that oxygen and other components in the air that are not consumed in the fuel cell stack 11 are discharged from the fuel cell stack 11 through the air pressure regulating valve 23.
[0024]
In the fuel cell 2 configured as described above, the solid polymer electrolyte type fuel cell stack 11 has a relatively low operating temperature of about 80 ° C., and needs to be cooled when overheated. Therefore, in the fuel cell 2 as described above, a cooling mechanism for cooling the fuel cell stack 11 by circulating cooling water and maintaining the fuel cell stack 11 at an optimum temperature is provided. Omitted.
[0025]
Although the specific configuration of the fuel cell 2 has been described above, in the present embodiment, the above-described hydrogen supply system and air supply system are provided with shut-off valves, respectively, as shut-off mechanisms. The pressure is maintained. Specifically, in the hydrogen supply system, a high-pressure shutoff valve 24 is provided between the high-pressure hydrogen tank 12 and the hydrogen pressure regulating valve 13 so that the inlet side of the fuel cell stack 11 of the hydrogen electrode passage can be shut off and purged. The valve 18 functions as a shut-off mechanism to shut off the fuel cell stack 11 outlet side of the hydrogen electrode passage. In the air supply system, an inlet-side air shutoff valve 25 is provided between the compressor 20 and the air pressure sensor 23, and an outlet-side air shutoff valve 26 is provided downstream of the air pressure regulating valve 21. The entrance and exit sides can be shut off.
[0026]
In the fuel cell 2, when the controller 9 determines that the fuel cell 2 is in the idle state based on information from the vehicle speed sensor 6, the shutoff valves 24, 25, and 26 and the purge valve 18, which are shutoff mechanisms, are transmitted from the controller 9. The operation is performed based on the control signal, and the hydrogen electrode passage, the air electrode passage, and the fuel cell stack 11 are hermetically sealed, so that a pressure drop inside these is prevented. Hereinafter, a control flow at the time of the idle stop will be described.
[0027]
FIG. 3 shows an example of the relationship between the power generated by the fuel cell stack 11, the hydrogen pressure, and the air pressure. As can be seen from FIG. 3, the larger the generated power, the higher the flow rates of hydrogen and air, and the higher these pressures must be. Therefore, in consideration of restarting, it is preferable to suppress the pressure drop during the idle stop as much as possible, and the following control flow becomes effective.
[0028]
The control flow in the present embodiment includes an idle stop determination flow for determining whether or not an idle stop is performed, and an idle stop operation flow when it is determined that the idle stop is performed.
[0029]
First, the idle stop determination flow is shown in FIG. When determining whether or not to stop idling, first, it is detected whether an ignition switch (not shown) operated by the driver is on or off (step S1). Here, if the ignition switch is turned off, it is considered that power generation is not required immediately thereafter, so that an operation stop operation for completely stopping the vehicle (fuel cell power generation system) is performed (step S7).
[0030]
In the operation stop operation, the operation of the compressor 20 is stopped, the high-pressure shutoff valve 24 is closed, and the supply of new air and hydrogen is stopped. Further, the purge valve 18, the outlet-side air shutoff valve 26, and the air pressure regulating valve 23 are all fully opened, and the fuel cell stack 11, the hydrogen electrode passage, and the air electrode passage are opened to the atmosphere.
[0031]
When the ignition switch is ON, it is determined whether or not the required power generation amount (driver's driving force request) is equal to or lower than a predetermined value (step S2), and whether or not the vehicle speed is equal to or lower than a predetermined speed (step S3). In each step, it is determined whether or not the charge capacity of the battery is sufficient (step S4), and it is determined whether or not to perform the idle stop. When these conditions are satisfied, that is, when the required power generation amount is equal to or less than the predetermined value, the vehicle speed is equal to or lower than the predetermined speed, and the charge capacity of the battery is sufficient, the power generation in the fuel cell stack 11 at that time is performed. May be stopped, but it is highly likely that power generation will need to be restarted immediately (within a few minutes). Therefore, it is determined that idle stop is to be performed instead of operation stop operation, and the idle stop mode (step S5) is entered. Transition. As to the determination of the idle stop, other operation parameters may be added, or another determination method may be applied, as in the related art.
[0032]
If the condition is not satisfied in any of the above steps (step S2, step S3, step S4), that is, the required power generation amount is equal to or higher than a predetermined value, the vehicle speed is equal to or higher than a predetermined speed, If the charge capacity of the fuel cell stack is insufficient, the power generation of the fuel cell stack 11 is continued (step S6).
[0033]
When it is determined that the idle stop is to be performed according to the idle stop determination flow described above, the shutoff valves and the like are operated based on the idle stop operation flow shown in FIG.
[0034]
At the time of idling stop, first, the purge valve 18 of the hydrogen supply system is opened (step S11). Next, the relay 8 is turned off, and the fuel cell stack 11 is disconnected from the load circuit (step S12). As a result, power is not taken out from the fuel cell stack 11.
[0035]
Next, the high-pressure shutoff valve 24 provided in the hydrogen supply system is closed so that new supply of hydrogen is not performed (step S13). Thereafter, the hydrogen pressure regulating valve 13 is opened, and the hydrogen gas upstream of the hydrogen pressure regulating valve 13 flows to the inlet of the fuel cell stack 11 (step S14).
[0036]
Subsequently, it is determined whether the hydrogen pressure at the inlet of the fuel cell stack 11 is equal to or higher than a predetermined value, based on the value detected by the hydrogen pressure sensor 17 provided at the inlet of the fuel cell stack 11. The predetermined value here may be determined based on the characteristic shown in FIG. 3 on the basis of how much power can be instantaneously generated when returning from idle stop (step S15). If it is determined in step S15 that the value detected by the hydrogen pressure sensor 16 is equal to or greater than the predetermined value, the processing in step S15 is repeated until it is determined that the value is equal to or less than the predetermined value. If it is determined that the value detected by the hydrogen pressure sensor 16 is smaller than the predetermined value, the purge valve 18 is closed to close the hydrogen electrode passage (step S16).
[0037]
Next, the compressor 20 is stopped (Step S17), and the outlet-side air shut-off valve 26 is closed (Step S18). Then, the air pressure regulating valve 21 is almost fully opened to balance the pressure of the entire air supply system (step S19). Here, the compressor 20 acts as a throttle, and the pressure of the air supply system changes relatively slowly.
[0038]
In step 20, it is determined whether or not the air pressure at the inlet of the fuel cell stack 11 is equal to or higher than a predetermined value based on the value detected by the air pressure sensor 2 provided at the inlet of the fuel cell stack 11. The predetermined value here may be determined based on the characteristic shown in FIG. 3 based on how much power can be instantaneously generated when returning from the idle stop, similarly to the hydrogen side. Further, when it is necessary to make the pressure difference with the hydrogen electrode side equal to or less than a predetermined value, the pressure difference may be determined in consideration of the difference. If it is determined in step S20 that the air pressure is equal to or higher than the predetermined value, the process of step S20 is repeated until it is determined that the air pressure is equal to or lower than the predetermined value. When it is determined that the air pressure is smaller than the predetermined value, the inlet-side air shut-off valve 25 is closed to close the air electrode passage (step S21).
[0039]
The above is the control flow at the time of idling stop. In the related art, the supply of the reactant gas is stopped and the hydrogen electrode passage and the air electrode passage are opened at the time of idling stop. Had become. In such a configuration, the next time power generation is performed, a time is required to increase the pressure of air or hydrogen to a pressure necessary for extracting predetermined power. For this reason, there has been a problem that it is not possible to respond to a quick start and power take-out request as required for an idle stop of an automobile.
[0040]
On the other hand, in the present embodiment, since the hydrogen electrode passage and the air electrode passage are sealed while keeping the pressure of hydrogen and air, when the idle stop is released and the fuel cell is again powered, The hydrogen or air pressure can be raised to the required pressure over time.
[0041]
Further, by defining the above-described operation order when the idle stop is started, it is possible to suppress an increase in the differential pressure between the hydrogen pressure and the air pressure when the idle stop is performed. Deterioration of the performance of the film can be prevented.
[0042]
Furthermore, if hydrogen and air are sealed while maintaining the pressure for a long time when power generation is stopped, there is a possibility that the pressure balance may be lost and the durability of the fuel cell may be degraded, but in this embodiment, power generation is stopped. In some cases, the hydrogen and the air are sealed while maintaining the pressure only when the engine is stopped at an idle state. At the time of a normal operation stop, the air is released to the atmosphere, so that such an adverse effect does not occur.
[0043]
In the present embodiment, since the purge valve 18 required for the hydrogen gas circulation system is used as a shut-off valve for closing the hydrogen electrode passage, there is also an advantage that cost increase can be suppressed.
[0044]
(Second embodiment)
This embodiment is an example in which a step of suppressing the pressure difference between the air electrode and the hydrogen electrode of the fuel cell stack 11 is added to the idling stop operation flow of the above-described first embodiment. The basic configurations of the fuel cell vehicle and the fuel cell 2 in the present embodiment are the same as those in the above-described first embodiment, and thus description thereof will be omitted.
[0045]
FIG. 6 shows an operation flow at the time of idling stop in this embodiment. Also in the present embodiment, similarly to the first embodiment described above, after determining the idle stop (see FIG. 4), the idle stop operation flow shown in FIG. 6 is performed.
[0046]
Steps S31 to S39 in the present embodiment are the same as steps S11 to S19 of the control flow shown in FIG. After the air pressure regulating valve 21 is fully opened in step S39, the detection value of the air pressure sensor 22 at the entrance of the fuel cell stack 11 and the detection value of the hydrogen pressure sensor 16 at the entrance of the fuel cell stack 11 are compared. It is determined whether the pressure is lower than a predetermined value or more (step S40).
[0047]
If it is determined in step S40 that the pressure is smaller than the predetermined value, that is, if the air pressure at the inlet of the fuel cell stack 11 is lower than the hydrogen pressure and the differential pressure is higher than the predetermined value, the compressor 20 is driven again. (Step 41). At this time, since the outlet side air shutoff valve 26 is in the closed state, the pressure in the air electrode passage of the air supply system increases. Then, the process returns to step S40 again, and repeats the process of step S41 until it is determined that the differential pressure is equal to or less than the predetermined value. Then, when it is determined that the differential pressure is smaller than the predetermined value, the inlet side air shutoff valve 25 and the outlet side air shutoff valve 26 are closed to close the air electrode passage (Step S42).
[0048]
In the present embodiment, when the differential pressure between air and hydrogen is equal to or higher than a predetermined value, the compressor 20 is driven before closing the inlet-side air shut-off valve 25 downstream of the compressor 20, and the air pressure at the inlet of the fuel cell stack 11 is increased. Is adjusted. Therefore, it is possible to suppress an increase in the differential pressure between the hydrogen pressure and the air pressure during execution of the idle stop, and to prevent performance degradation of the polymer membrane of the fuel cell stack 11.
[0049]
Further, in addition to the effects of the first embodiment, the differential pressure between the air pressure and the hydrogen pressure can be easily controlled, and the hermetic seal can be performed at a higher pressure. More electric power can be quickly extracted from the battery stack 11.
[0050]
(Third embodiment)
The present embodiment relates to an idling stop operation flow when humidifying air and hydrogen supplied to the fuel cell stack 11. The configuration of the fuel cell 2 is basically the same as that shown in FIG. 2 in the first embodiment, but humidifies air and hydrogen gas on the inlet side of the fuel cell stack 11 as shown in FIG. A humidifier 27 is added.
[0051]
The general polymer membrane type fuel cell 2 needs some humidifying device for humidifying air or hydrogen in order to wet the polymer membrane used for the electrolyte of the fuel cell stack 11. FIG. 8 shows an operation flow at the time of idling stop when such a humidifying device is provided. This idle stop operation flow is also executed after the determination of the idle stop (see FIG. 4), as in the first embodiment.
[0052]
At the time of idling stop, first, the purge valve 18 of the hydrogen supply system is opened (step S51). Next, the relay 8 is turned off, and the fuel cell stack 11 is disconnected from the load circuit (Step S52). As a result, power is not taken out from the fuel cell stack 11.
[0053]
Next, in response to the fact that power is not taken out from the fuel cell stack 11, the humidifying operation of the humidifier 27 is stopped (step S53). As a method of stopping the humidifying operation, for example, a method of stopping the supply of pure water to the humidifier 27 may be provided, or a gas flow path may be provided to bypass the humidifier 27, and both the hydrogen gas and the air pass through the humidifier 27. A method that does not cause a problem may be used.
[0054]
Subsequent steps S54 to S63 are the same as steps S33 to S42 in the second embodiment, and a description thereof will be omitted.
[0055]
In the present embodiment, since the humidification of the sealed hydrogen and air is not performed, in addition to the effects of the first and second embodiments, the condensed water due to the temperature drop in the fuel cell stack 11 when the power generation is stopped. The effect that generation can be suppressed can be obtained. For this reason, at the time of return from the idle stop, a decrease in the cell voltage due to water clogging in the fuel cell stack 11 can be suppressed, and more power can be quickly extracted from the fuel cell stack 11.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a basic configuration of a fuel cell vehicle.
FIG. 2 is a diagram showing a specific configuration example of a fuel cell power generation system.
FIG. 3 is a characteristic diagram showing the relationship between the power generated by a fuel cell and the required hydrogen pressure and air pressure.
FIG. 4 is a flowchart illustrating an idle stop determination flow according to the first embodiment.
FIG. 5 is a flowchart illustrating an operation flow at the time of idling stop according to the first embodiment.
FIG. 6 is a flowchart illustrating an idling stop operation flow according to a second embodiment.
FIG. 7 is a diagram illustrating a specific configuration example of a fuel cell power generation system to which a humidifying device is added.
FIG. 8 is a flowchart showing an operation flow at the time of idling stop in the third embodiment.
[Explanation of symbols]
1 vehicle body
2 Fuel cell
3 Inverter
4 Drive motor
6 Vehicle speed sensor
7 Secondary battery
8 Relay
9 Control controller
11 Fuel cell stack
11a Hydrogen electrode
11b Air electrode
13 Hydrogen pressure regulating valve
15 Hydrogen supply piping
16 Hydrogen circulation piping
17 Hydrogen pressure sensor
18 Purge valve
20 Compressor
21 Air pressure regulating valve
22 Air supply piping
23 Air pressure sensor
24 High pressure shut-off valve
25 Inlet side air shutoff valve
26 Outlet side air shut-off valve
27 Humidifier

Claims (14)

Air supply means and hydrogen supply means, an air electrode passage for guiding air from the air supply means to the air electrode of the fuel cell stack, and a hydrogen electrode passage for guiding hydrogen from the hydrogen supply means to the hydrogen electrode of the fuel cell stack In a fuel cell vehicle in which a fuel cell having
The fuel cell vehicle according to claim 1, wherein the air electrode passage is provided with an air shutoff mechanism on the inlet side and the outlet side with respect to the fuel cell stack, which shuts off the air electrode passage when idling is stopped. The air supply unit includes a compressor that feeds air to an air electrode of the fuel cell stack, and an air adjustment valve that controls at least one of a flow rate and a pressure of air supplied to an air electrode of the fuel cell stack. ,
The air regulating valve is provided on an outlet side of the air electrode passage,
2. The fuel cell vehicle according to claim 1, wherein the air cutoff mechanism is provided on a downstream side of the compressor and a downstream side of the air regulating valve, respectively. 3. 3. The fuel cell vehicle according to claim 2, wherein the drive of the compressor is stopped when the engine is idling. The fuel cell vehicle according to any one of claims 1 to 3, further comprising control means for determining an idle stop state, wherein the air cutoff mechanism is opened and closed based on information from the control means. The hydrogen electrode passage is provided with a hydrogen shutoff mechanism for shutting off the hydrogen electrode passage when idling is stopped on an inlet side and an outlet side with respect to the fuel cell stack. A fuel cell vehicle according to claim 1. The hydrogen supply unit includes a hydrogen supply source, and a hydrogen adjustment valve that controls at least one of a flow rate and a pressure of hydrogen supplied to a hydrogen electrode of the fuel cell stack,
The hydrogen regulating valve is provided on the inlet side of the hydrogen electrode passage,
The fuel cell vehicle according to claim 5, wherein the hydrogen cutoff mechanism is provided between the hydrogen supply source and the hydrogen regulating valve. 6. The hydrogen supply device according to claim 5, wherein the hydrogen supply unit has a circulation path for circulating hydrogen discharged from a hydrogen electrode of the fuel cell stack and a purge valve, and the purge valve functions as the hydrogen cutoff mechanism. 7. The fuel cell vehicle according to 6. The fuel cell vehicle according to any one of claims 1 to 7, further comprising a humidifier for humidifying at least one of hydrogen and air supplied to the fuel cell stack. Air supply means and hydrogen supply means, an air electrode passage for guiding air from the air supply means to the air electrode of the fuel cell stack, and a hydrogen electrode passage for guiding hydrogen from the hydrogen supply means to the hydrogen electrode of the fuel cell stack In a control method of a fuel cell vehicle in which a fuel cell including
An air shutoff mechanism for shutting off the air electrode passage is provided on an inlet side and an outlet side of the air electrode passage with respect to the fuel cell stack, and when the idle is stopped, the air electrode passage is shut off by the air shut off mechanism. Control method for a fuel cell vehicle. A shutoff mechanism for shutting off the hydrogen electrode passage is provided on an inlet side and an outlet side of the hydrogen electrode passage with respect to the fuel cell stack, and when the idle is stopped, the hydrogen electrode passage is shut off by the hydrogen shutoff mechanism. The control method for a fuel cell vehicle according to claim 9. 11. The hydrogen supply device according to claim 10, wherein a circulation path for circulating hydrogen discharged from a hydrogen electrode of the fuel cell stack and a purge valve are provided, and the purge valve functions as the hydrogen cutoff mechanism. Control method for a fuel cell vehicle. As the air supply means, a compressor that feeds air to the air electrode of the fuel cell stack, and an air adjustment valve that controls at least one of the flow rate and pressure of air supplied to the air electrode of the fuel cell stack, The air regulating valve is provided on the outlet side of the air electrode passage, and the air shutoff mechanism is provided on the downstream side of the compressor and on the downstream side of the air regulating valve, respectively.
As the hydrogen supply means, a hydrogen supply source and a hydrogen adjustment valve for controlling at least one of a flow rate and a pressure of hydrogen supplied to a hydrogen electrode of the fuel cell stack are provided, and the hydrogen adjustment valve is connected to the hydrogen electrode passage. And the hydrogen shutoff mechanism is provided between the hydrogen supply source and the hydrogen regulating valve,
At the time of idle stop, first, the purge valve is opened, then the hydrogen shutoff mechanism provided between the hydrogen supply source and the hydrogen adjustment valve is shut off, and then the hydrogen adjustment valve is opened. Next, shut off the purge valve, then stop driving the compressor, then shut off the air shutoff mechanism provided downstream of the air adjustment valve, and then fully open the air adjustment valve 12. The method according to claim 11, further comprising shutting off an air shutoff mechanism provided downstream of the compressor. At the time of idle stop, the air pressure in the air electrode passage is compared with the hydrogen pressure in the hydrogen electrode passage. If the air pressure is smaller than the hydrogen pressure by a predetermined value or more, air is supplied from the air supply means to reduce the air pressure. The method for controlling a fuel cell vehicle according to any one of claims 9 to 12, wherein: 10. A humidifier for humidifying at least one of hydrogen and air supplied to the fuel cell stack, wherein a humidifying operation of the humidifier is stopped or a humidifying capacity is reduced when idling is stopped. 14. The control method for a fuel cell vehicle according to any one of claims 13 to 13.

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