JP2020014352A - Fuel cell vehicle - Google Patents

Abstract

To provide a technique for more accurately reflecting the actual frozen state in a fuel cell to a determination result of a travel permission.SOLUTION: When a start instruction is inputted to a fuel cell vehicle, the power generation of the fuel cell is set to start, and the amount of generated electric charge after the start instruction is inputted is to be detected using the output current of the fuel cell. In the case of the temperature of the fuel cell being below the freezing point and the amount of generated electric charge is less than a preset reference value, it is determined that traveling of the fuel cell vehicle cannot be permitted. In the case of the temperature of the fuel cell exceeding the freezing point, and in the case of the temperature of the fuel cell being below the freezing point and the amount of generated electric charge is equal to the preset reference value or greater, the fuel cell vehicle is set in a travelable state.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a fuel cell vehicle.

  It is assumed that the fuel cell vehicle is started under various temperature conditions. In a fuel cell, since water is generally generated with power generation, liquid water may stay in a reaction gas flow path in the fuel cell. When the fuel cell vehicle is started under a subzero temperature condition, if the liquid water remaining in the fuel cell is frozen, the reaction gas cannot be sufficiently circulated in the fuel cell, which hinders the power generation of the fuel cell. May occur. Therefore, conventionally, as a countermeasure at the time of starting under low temperature conditions, it is determined whether or not the outlet temperature of the refrigerant is below freezing at the time of starting the fuel cell vehicle. It has been proposed to mount a system for issuing a driving permission to a fuel cell vehicle when a condition is satisfied (for example, see Patent Document 1).

Japanese Patent Application Laid-Open No. 2017-195021

  However, in the above-described known system, the permission of running of the fuel cell vehicle is determined by indirectly using the outlet temperature of the cooling medium circulating in the fuel cell as an index indicating the frozen state of the fuel cell. . For this reason, the actual frozen state may not be accurately reflected in the determination result of the traveling permission.

  The present invention can be realized as the following modes.

According to one aspect of the present invention, a fuel cell vehicle equipped with a fuel cell is provided. The fuel cell vehicle has a temperature sensor capable of measuring the temperature of the fuel cell, an output limiting unit that limits an output current of the fuel cell when an output voltage of the fuel cell falls below a target voltage, A control unit that controls a running state of the fuel cell vehicle, wherein the control unit causes the fuel cell vehicle to start power generation when a start instruction is input to the fuel cell vehicle, and Using the output current of the battery, the amount of generated electric charge in the fuel cell after the start instruction is input is detected, the temperature of the fuel cell detected by the temperature sensor is below freezing, and the generated electric charge is When the amount is less than a predetermined reference value, it is determined that traveling of the fuel cell vehicle cannot be permitted, and when the temperature of the fuel cell detected by the temperature sensor exceeds a freezing point, Temperature of the fuel cell out is below freezing, and, in the case the amount of the power generation electric charge is equal to or larger than the reference value, at, to the travelable state the fuel cell vehicle.
According to the fuel cell vehicle of this embodiment, when the temperature of the fuel cell is below freezing, it is not possible to permit the fuel cell to travel based on the amount of charge generated after the fuel cell starts generating power according to the start instruction. Or whether the fuel cell can be run. That is, if the amount of generated electric charge of the fuel cell is less than the reference value, it is considered that the output of the fuel cell is limited due to lack of hydrogen supply due to freezing and the output of the fuel cell is not obtained, and therefore the fuel cell is in a frozen state. It is determined that the vehicle cannot be permitted to travel. As described above, when the fuel cell is started at a low temperature, the freezing determination is performed based on a phenomenon that actually occurs in the fuel cell, and the frozen state is indirectly estimated based on the temperature of the refrigerant circulating in the fuel cell. In comparison, the determination of freezing can be made more accurately, and the result can be reflected in the determination of travel permission.
The present invention can be realized in various forms, for example, in the form of a control method for a fuel cell vehicle, a computer program for realizing the control method, a non-transitory recording medium storing the computer program, and the like. can do.

FIG. 1 is a block diagram illustrating a schematic configuration of a fuel cell vehicle. FIG. 3 is an explanatory diagram showing a control unit by functional blocks. It is a flowchart showing a running permission / inhibition determination processing routine. It is explanatory drawing showing the mode that the amount of generated electric charges changes after a warming-up operation | movement start. It is a flowchart showing a running permission / inhibition determination processing routine. It is explanatory drawing showing the mode that the amount of generated electric charges changes after a warming-up operation | movement start. FIG. 3 is an explanatory diagram showing a control unit by functional blocks. It is a flowchart showing a running permission / inhibition determination processing routine. It is a flowchart showing a running permission / inhibition determination processing routine.

A. First embodiment:
(A-1) Overall configuration of fuel cell vehicle:
FIG. 1 is a block diagram showing a schematic configuration of a fuel cell vehicle 20 as a first embodiment according to the present invention. The fuel cell vehicle 20 includes a motor 170 that generates driving force for the vehicle, a fuel cell system 30 including the fuel cell 100, and a secondary battery 172 that can supply power for driving the fuel cell vehicle 20 to the vehicle body 22. And a control unit 200. In the fuel cell vehicle 20, each of the fuel cell 100 and the secondary battery 172 can supply power to the load including the motor 170 independently or simultaneously from both of the fuel cell 100 and the secondary battery 172. I have. The fuel cell 100 and the load including the motor 170 are connected via the DC / DC converter 104 and the wiring 178. The DC / DC converter is connected between the secondary battery 172 and the load including the motor 170. They are connected via a converter 174 and a wiring 178. The DC / DC converter 104 and the DC / DC converter 174 are connected in parallel to the wiring 178.

  The fuel cell system 30 includes, in addition to the fuel cell 100, a hydrogen gas supply unit 120 including a hydrogen tank 110 and an air supply unit 140 including a compressor 130. Further, the fuel cell system 30 further includes a not-shown refrigerant circulating unit for circulating a refrigerant for keeping the temperature of the fuel cell 100 within a predetermined range in the fuel cell 100.

  The fuel cell 100 has a stack configuration in which a plurality of single cells are stacked. Although the fuel cell 100 of this embodiment is a polymer electrolyte fuel cell, other types of fuel cells may be used. In each unit cell constituting the fuel cell 100, a flow path through which hydrogen as a fuel gas flows (hereinafter, also referred to as an anode flow path) is formed on the anode side with an electrolyte membrane interposed therebetween, and an oxidizing gas flow is formed on the cathode side. (Hereinafter, also referred to as a cathode-side flow path) is formed. A wiring 178 connecting the fuel cell 100 and the DC / DC converter 104 is provided with a voltage sensor 102 for detecting an output voltage of the fuel cell 100 and a current sensor 103 for detecting an output current of the fuel cell 100. I have. Further, the fuel cell 100 is provided with a temperature sensor 105 capable of measuring the temperature of the fuel cell 100. The temperature sensor 105 may be, for example, a temperature sensor that is provided in the above-described refrigerant flow path and detects the temperature of the refrigerant discharged from the fuel cell 100 after circulating in the fuel cell 100. Alternatively, a sensor that directly detects the internal temperature of the fuel cell 100 may be used as the temperature sensor 105. Further, the fuel cell 100 is provided with a cell monitor (not shown) that is used to detect the output voltage of each single cell constituting the fuel cell 100 and detect a single cell that generates a negative voltage. The detection signals of the voltage sensor 102, the current sensor 103, the temperature sensor 105, and the cell monitor are output to the control unit 200.

  The hydrogen tank 110 included in the hydrogen gas supply unit 120 can be, for example, a tank that stores high-pressure hydrogen gas. The hydrogen gas supply unit 120 includes a hydrogen supply channel 121 extending from the hydrogen tank 110 to the fuel cell 100, a circulation channel 122 for circulating unconsumed hydrogen gas (anode off gas) to the hydrogen supply channel 121, and an anode off gas. And a hydrogen release channel 123 for releasing hydrogen into the atmosphere. In the hydrogen gas supply unit 120, the hydrogen gas stored in the hydrogen tank 110 passes through the opening and closing of the opening and closing valve 124 of the hydrogen supply passage 121 and the pressure of the hydrogen is reduced by the pressure reducing valve 125. The fuel is supplied from the device 126 (for example, an injector) to the anode-side flow path of the fuel cell 100. The pressure of hydrogen circulating in the circulation channel 122 is adjusted by a circulation pump 127. The driving amounts of the hydrogen supply device 126 and the circulation pump 127 are adjusted by the control unit 200 according to the load request while referring to the pressure of the circulating hydrogen detected by the pressure sensor 128.

  A part of the hydrogen gas flowing through the circulation channel 122 is released to the atmosphere at a predetermined timing after opening and closing the opening and closing valve 129 of the hydrogen release channel 123 branched from the circulation channel 122. Thereby, impurities other than hydrogen (such as water vapor and nitrogen) in the hydrogen gas circulating in the circulation channel 122 can be discharged to the outside of the channel, and the impurity concentration in the hydrogen gas supplied to the fuel cell 100 can be reduced. The rise can be suppressed. The opening / closing timing of the opening / closing valve 124 is adjusted by the control unit 200.

  The air supply unit 140 includes, in addition to the compressor 130, a first air flow path 141, a second air flow path 145, a third air flow path 146, a branch valve 144, an air discharge flow path 142, a back pressure valve 143, And a flow sensor 147. The first air flow path 141 is a flow path through which the entire amount of air taken in by the compressor 130 flows. The second air flow path 145 and the third air flow path 146 are provided to be branched from the first air flow path 141. The flow dividing valve 144 is provided at a location where the first air flow path 141 branches into the second air flow path 145 and the third air flow path 146, and changes the open state of the flow dividing valve 144. Thereby, the distribution ratio of the air flowing from the first air passage 141 to the second air passage 145 or the third air passage 146 can be changed. Part of the second air flow path 145 forms a cathode-side flow path in the fuel cell 100. The third air flow path 146 is a bypass flow path that guides air without passing through the fuel cell 100. The second air flow path 145 and the third air flow path 146 merge to form an air discharge flow path 142. The back pressure valve 143 is a throttle valve provided in the second air flow path 145 downstream of the cathode-side flow path and upstream of a junction with the third air flow path 146. By adjusting the opening degree of the back pressure valve 143, the back pressure of the cathode side flow path in the fuel cell 100 can be changed. The air release channel 142 is a channel for releasing the air (cathode off-gas) passing through the second air channel 145 to the atmosphere together with the air passing through the third air channel 146. The above-described hydrogen release channel 123 is connected to the air release channel 142, and hydrogen released through the hydrogen release channel 123 is supplied to the air flowing through the air release channel 142 prior to atmospheric release. Diluted by The flow rate sensor 147 is provided in the first air flow path 141 and detects a total flow rate of air taken in through the first air flow path 141.

  In the air supply unit 140, by changing at least one condition selected from the driving amount of the compressor 130, the opening state of the flow dividing valve 144, and the opening degree of the back pressure valve 143, the cathode-side flow path of the fuel cell 100 is changed. The flow rate (oxygen flow rate) of the air supplied to the device can be adjusted. The drive amount of the compressor 130, the open state of the flow dividing valve 144, and the opening of the back pressure valve 143 are adjusted by the control unit 200. The air supply unit 140 may include a humidifier that humidifies the air to be supplied to the fuel cell 100, for example, in the first air flow path 141.

  The secondary battery 172 can be composed of, for example, a lithium ion battery or a nickel hydride battery. The secondary battery 172 is provided with a secondary battery monitor 173. The rechargeable battery monitor 173 sets the remaining capacity of the rechargeable battery 172 and the maximum output that is the maximum value of the output power allowed for the rechargeable battery 172 (hereinafter, referred to as the rechargeable battery Output Wout). The detected output possible state of the secondary battery 172 is output to the control unit 200.

  The remaining capacity of the secondary battery 172 is an index indicating how much the secondary battery 172 is charged. The secondary battery monitor 173 may detect the remaining capacity by, for example, integrating the charge and discharge current values and time in the secondary battery 172 with time. Alternatively, the remaining capacity may be obtained using the voltage of the secondary battery 172.

  The secondary battery output Wout is the maximum value of output power when power is supplied from the secondary battery 172 while suppressing deterioration of the secondary battery 172, and depends on the remaining capacity and the temperature of the secondary battery 172. Generally, if the remaining capacity of the secondary battery 172 is large, the output Wout of the secondary battery is large, and if the remaining capacity of the secondary battery 172 is small, the output Wout of the secondary battery is small. The lower the temperature of the secondary battery 172, the lower the secondary battery output Wout, and the higher the temperature of the secondary battery 172, the higher the secondary battery output Wout. Therefore, for example, the relationship between the remaining capacity and temperature of the secondary battery 172 and the output Wout of the secondary battery 172 is obtained in advance through experiments or the like and stored as a map. The secondary battery output Wout may be obtained based on the capacity and the temperature. However, if the remaining capacity of the secondary battery 172 is a value within the range of the normal operation of the secondary battery 172, the effect of the remaining capacity on the secondary battery output Wout is small, and the secondary battery output Wout is substantially the only temperature. Depends on. Therefore, the secondary battery output Wout may be obtained using only the temperature of the secondary battery 172. Although FIG. 1 illustrates that the secondary battery 172 includes the secondary battery monitor 173, the above-described function executed by the secondary battery monitor 173 may be included in, for example, the control unit 200.

  The DC / DC converter 104 has a function of receiving a control signal from the control unit 200 and changing the output state of the fuel cell 100. Specifically, the DC / DC converter 104 extracts current and voltage from the fuel cell 100 toward the load, and controls the current and voltage extracted from the fuel cell 100 by switching control in the DC / DC converter 104. Further, when supplying the power generated by the fuel cell 100 to a load such as the motor 170, the DC / DC converter 104 boosts the output voltage of the fuel cell 100 to a voltage usable by the load.

  The DC / DC converter 174 has a charge / discharge control function of controlling the charge / discharge of the secondary battery 172, and controls the charge / discharge of the secondary battery 172 in response to a control signal from the control unit 200. In addition, the DC / DC converter 174 sets the target voltage on the output side under the control of the control unit 200, thereby extracting the stored power of the secondary battery 172 and applying the voltage to the motor 170, and thereby extracting the power. The state and the voltage level applied to the motor 170 are variably adjusted. The DC / DC converter 174 disconnects the connection between the secondary battery 172 and the wiring 178 when the secondary battery 172 does not need to be charged and discharged.

  The control unit 200 is configured by a so-called microcomputer including a CPU that executes a logical operation, a ROM, a RAM, and the like. The control unit 200 outputs detection signals from various sensors such as an accelerator opening sensor 180, a shift position sensor, a vehicle speed sensor, and an outside temperature sensor, in addition to the sensors described above included in the hydrogen gas supply unit 120 and the air supply unit 140. After the acquisition, various controls related to the fuel cell vehicle 20 are performed. For example, the control unit 200 obtains the magnitude of the load request based on the detection signal of the accelerator opening sensor 180 and the like, and the power corresponding to the load request is obtained from at least one of the fuel cell 100 and the secondary battery 172. Then, a drive signal is output to each unit. Specifically, when power is obtained from the fuel cell 100, the amount of gas supplied from the hydrogen gas supply unit 120 and the air supply unit 140 is controlled so that desired power is obtained from the fuel cell 100. Further, control unit 200 controls DC / DC converters 104 and 174 such that desired power is supplied from at least one of fuel cell 100 and secondary battery 172 to a load such as motor 170. The control unit 200 further includes a timer, and can measure an elapsed time after inputting various signals or executing various processes.

(A-2) Startup control:
FIG. 2 is an explanatory diagram showing the control unit 200 by functional blocks representing some of the functions executed by the control unit 200. The control unit 200 includes, as functional blocks, a charge detection unit 210, a freeze determination unit 220, a travel determination unit 230, a travel control unit 240, a power generation control unit 250, and an output restriction unit 260. When starting under low temperature conditions, the fuel cell vehicle 20 of the present embodiment determines whether or not the reaction gas flow path in the fuel cell 100 is frozen while performing a warm-up operation. Based on this, it is determined whether the fuel cell vehicle 20 can run. If the fuel cell 100 performs power generation in a state where the reaction gas flow path is frozen, the reaction gas cannot be sufficiently circulated in the fuel cell 100, which may hinder power generation. The functional blocks shown in FIG. 2 are involved in performing such an operation. Hereinafter, the operation at the time of starting the fuel cell vehicle 20 will be described.

  FIG. 3 is a flowchart showing a running permission / inhibition determination processing routine executed by CPU of control unit 200 when fuel cell vehicle 20 is started. This routine is executed when an instruction to start the fuel cell system 30 is input to enable the fuel cell vehicle 20 to travel, specifically, when the start switch 25 (see FIG. 2) is pressed by the driver. Is started.

  When this routine is started, the CPU of the control unit 200 controls the power generation of the fuel cell 100 to start the warm-up operation of the fuel cell 100 (step S100). The warm-up operation refers to an operation state in which the temperature of the fuel cell 100 is actively raised so that the temperature of the fuel cell 100 reaches a predetermined temperature range as a steady state. When the temperature of the fuel cell 100 at the time of startup is below freezing, first, a warm-up operation is performed so that the temperature of the fuel cell 100 exceeds the freezing point. After the temperature of the fuel cell 100 exceeds the freezing point due to the warm-up operation, or in a low temperature condition where the temperature of the fuel cell 100 at the time of starting is higher than the freezing point, the temperature of the fuel cell 100 is predetermined as a steady state. The warm-up operation is performed so as to reach the set temperature range. In the warm-up operation performed under a low temperature condition in which the temperature of the fuel cell 100 exceeds the freezing point, more power can be output from the fuel cell 100 than in the warm-up operation performed when the fuel cell 100 is below the freezing point. Become.

  As the warming-up operation, for example, a method of increasing the power generation loss of the fuel cell 100 by increasing the oxygen concentration overvoltage by controlling the flow rate of the oxidizing gas supplied to the fuel cell 100 and increasing the temperature by self-heating is adopted. Can be. The operation of step S100 is performed by the power generation control unit 250 (see FIG. 2).

  When the warm-up operation is started in step S100, control for limiting the output current of the fuel cell 100 based on the output state of the fuel cell 100 is performed together with the warm-up operation. At the time of the warm-up operation, the power generation point of the fuel cell 100, that is, the target voltage and the target current of the fuel cell 100 are set so that the self-heating is increased as described above. When the fuel gas flow path in the fuel cell 100 is frozen when the warm-up operation is performed at the set power generation point, the amount of hydrogen supplied to the anode is insufficient, and the single cell in which the freeze occurs , A negative voltage is generated. If the warm-up operation is continued in such a state, inconveniences such as damage to the fuel cell 100 may occur. In the present embodiment, when a single cell with a negative voltage is detected, the output current is limited to suppress the power generation amount, thereby suppressing the above-described inconvenience. The control for limiting the output current is performed by the output limiting unit 260 of the control unit 200 (see FIG. 2). When a single cell with a negative voltage is detected, output limiter 260 changes the operation point during warm-up operation set by power generation controller 250 so that the output current is limited to a predetermined upper limit or less. . The limitation of the output current described above is not limited to the detection of a single cell with a negative voltage, but may be performed when the presence of a single cell with insufficient hydrogen supplied to the anode is detected. For example, an AC signal may be superimposed on a current drawn from the fuel cell 100, and the impedance of the fuel cell 100 may be detected by an AC impedance method. When the impedance value of the fuel cell 100 when an AC signal of a low frequency (for example, 1 to 100 Hz) is applied becomes larger than a predetermined reference value, a single cell deficient in hydrogen occurs. And the output current may be limited. When the low-frequency AC signal is superimposed as described above, the obtained impedance further includes, in addition to the resistance component, a reactance that reflects the moving resistance of the gas.

  When the warm-up operation is started in step S100, control unit 200 acquires the temperature of fuel cell 100 from temperature sensor 105, and determines whether the temperature of fuel cell 100 is below freezing (step S110). In step S110, it is determined whether the temperature of the fuel cell 100 is equal to or lower than 0 ° C. under the normal pressure environment. When the fuel cell vehicle 20 is used at a high altitude where the atmospheric pressure is lower, the freezing point to be compared in step S110 may be appropriately changed according to the atmospheric pressure of the use environment. The atmospheric pressure in the use environment may be directly detected by providing an atmospheric pressure sensor on the fuel cell vehicle 20, or may be estimated from the altitude of the location where the fuel cell vehicle 20 is located based on the position information of the fuel cell vehicle 20. May be.

  If it is determined in step S110 that the temperature of the fuel cell 100 is above the freezing point (step S110: NO), the control unit 200 proceeds to step S130, enables the fuel cell vehicle 20 to run, and ends this routine. I do. Step S130 will be described later.

  If it is determined in step S110 that the temperature of fuel cell 100 is below the freezing point (step S110: YES), control unit 200 determines whether or not the amount of charge generated by fuel cell 100 is equal to or greater than a predetermined reference value. (Step S120). The amount of electric charge generated by the fuel cell 100 can be obtained by integrating the product of the output current of the fuel cell 100 and time after the start instruction is input to the fuel cell vehicle 20. The charge detection unit 210 to which the detection signal of the current sensor 103 is input calculates the amount of charge generated by the fuel cell 100. Freezing determination section 220 receives the detection signal from temperature sensor 105 and makes the determination in step S110, and receives the amount of electric charge generated by fuel cell 100 from charge detection section 210, and makes the determination in step S120.

  FIG. 4 is an explanatory diagram illustrating a state in which the amount of generated power of the fuel cell 100 changes after the warm-up operation of the fuel cell 100 starts. The horizontal axis represents time, and the vertical axis represents generated electric charge. The time when the fuel cell system 30 is started, that is, the time when the warm-up operation starts is indicated as time t1. In a normal state in which freezing does not occur, the amount of electric charge generated by the fuel cell 100 increases with time. On the other hand, when freezing has occurred, the amount of generated electric charge increases as in the normal state until the amount of generated electric charge reaches the amount of electric charge α. Can be greatly suppressed. The charge amount α indicates a charge amount that can be generated by using hydrogen remaining inside the fuel cell 100 at the time of startup. After power generation is performed using the hydrogen remaining inside the fuel cell 100, if freezing occurs, the amount of hydrogen supplied to the anode is insufficient, and the output of the fuel cell 100 is reduced as described above. Since the current is limited, the degree of increase in the amount of generated electric charge is greatly suppressed.

  In the present embodiment, the charge amount β is used as the reference value used for the determination in step S120. The charge amount β is predetermined as a generated charge amount obtained from the fuel cell 100 until heat is generated to such an extent that the possibility of eliminating the freezing in the fuel cell 100 is sufficiently high. Therefore, if the generated electric charge is equal to or more than the electric charge β in step S120, it can be determined that the fuel cell 100 is not frozen. If the generated electric charge is less than the electric charge β, the fuel cell 100 freezes. It can be determined that. The operation of step S120 can be said to be an operation of determining whether or not the flow path of the reaction gas in the fuel cell 100 is frozen.

  If the generated electric charge is less than the electric charge β in step S120 (step S120: NO), the control unit 200 repeats the operation of step S120. In this way, when the operation of step S120 is repeated while continuing the warm-up operation, the freezing of the fuel cell 100 is gradually eliminated by the heat generated by the warm-up operation. In this manner, when the warm-up operation is continued and the generated electric charge becomes equal to or more than the electric charge β, or when the fuel cell 100 is not frozen from the start, the generated electric charge quickly becomes equal to or more than the electric charge β. When it does (step S120: YES), it is determined that the fuel cell 100 does not correspond to the frozen state, the control unit 200 enables the fuel cell vehicle 20 to run (step S130), and ends this routine.

  The operation of step S130 is performed by travel determination section 230 and travel control section 240. When the temperature of fuel cell 100 exceeds the freezing point (step S110: NO), traveling determination unit 230 determines that traveling of fuel cell vehicle 20 can be permitted. When the temperature of the fuel cell 100 is below freezing and the freeze determination unit 220 determines that the fuel cell 100 is not frozen (step S120: YES), the traveling determination unit 230 determines whether the fuel cell vehicle is running. It is determined that traveling of the vehicle 20 can be permitted. Then, in this case, the traveling control unit 240 controls the traveling state of the fuel cell vehicle 20 to make the fuel cell vehicle 20 operable. Specifically, the traveling control unit 240 turns on an indicator (also referred to as a READY indicator) provided on an instrument panel or the like disposed in front of the driver's seat and indicating that the fuel cell vehicle 20 can travel. , The driver is notified that the fuel cell vehicle 20 can run. Then, the traveling control unit 240 starts control for performing traveling using the fuel cell 100 and the secondary battery 172 as power supplies in accordance with a load request based on the accelerator opening and the like. However, until the temperature of the fuel cell 100 reaches a predetermined temperature range as a steady state, the fuel cell 100 performs power generation giving priority to heat generation, thereby controlling the output of the fuel cell 100 to be suppressed.

  The traveling determination unit 230 determines that the temperature of the fuel cell 100 is below the freezing point (step S110: YES), the generated electric charge is less than the electric charge β, and the freezing determination unit 220 determines that the fuel cell 100 is in a frozen state. If it has been performed (step S120: NO), it is determined that traveling of the fuel cell vehicle 20 cannot be permitted, and the process stands by.

  According to the fuel cell vehicle 20 of the present embodiment configured as described above, when the temperature of the fuel cell 100 is below the freezing point, the amount of charge generated after the power generation of the fuel cell 100 is started by the start instruction is started. Based on the determination, it is determined whether the travel of the fuel cell 100 cannot be permitted or whether the fuel cell 100 is in a travelable state. That is, if the amount of generated electric charge of the fuel cell 100 is less than a predetermined reference value, it is considered that the supply of hydrogen is insufficient due to freezing, the output of the fuel cell 100 is not obtained, and the output current is limited. Is in a frozen state, it is determined that traveling of the fuel cell vehicle 20 cannot be permitted. As described above, when the fuel cell 100 is started at a low temperature, the freezing state is estimated indirectly based on the temperature of the refrigerant circulating in the fuel cell 100 by determining the freezing based on the phenomenon actually occurring in the fuel cell 100. This makes it possible to accurately determine whether or not freezing has occurred. As a result, the result of the accurate freeze determination is reflected in the determination of the travel permission, and the travel control can be more appropriately performed.

B. Second embodiment:
FIG. 5 is a flowchart showing a running permission / inhibition determination processing routine executed by control unit 200 of fuel cell vehicle 20 when starting fuel cell vehicle 20 of the second embodiment. Since the fuel cell vehicle 20 according to the second embodiment has the same configuration as the fuel cell vehicle 20 according to the first embodiment shown in FIGS. 1 and 2, common portions are denoted by the same reference numerals, and are described in detail. Is omitted. The traveling propriety determination processing routine shown in FIG. 5 is executed instead of the traveling propriety determination processing routine of FIG. 3 in the first embodiment. In FIG. 5, steps common to those in FIG. 3 are denoted by the same step numbers, and detailed description is omitted.

  When a start instruction is input by operating the start switch 25 and this routine is started, the CPU of the control unit 200 starts the warm-up operation of the fuel cell 100 (step S100). It is determined whether the temperature is below the freezing point (step S110). If it is determined that the temperature of the fuel cell 100 exceeds the freezing point (step S110: NO), it is determined that the fuel cell 100 is not in a frozen state, so the process proceeds to step S130, and the fuel cell vehicle 20 The vehicle is allowed to run, and this routine ends. When it is determined that the temperature of the fuel cell 100 is below the freezing point (step S110: YES), the control unit 200 determines whether or not the amount of charge generated from the start is equal to or more than the reference value (step S120). . If the amount of electric charge generated from the start is equal to or more than the reference value (step S120: YES), it is determined that the fuel cell 100 is not in a frozen state, and thus the control unit 200 enables the fuel cell vehicle 20 to travel. Then (step S130), this routine ends.

  In the present embodiment, when the amount of electric charge generated from the start is less than the reference value (step S120: NO), the operation of step S120 is not simply repeated as in the first embodiment, but from the start of power generation at the start. It is further determined whether or not the elapsed time has passed a predetermined reference time (step S140).

  FIG. 6 is an explanatory diagram illustrating a state in which the amount of generated power of the fuel cell 100 changes after the warm-up operation of the fuel cell 100 starts. As in FIG. 4, the horizontal axis represents time, the vertical axis represents generated electric charge, and the time at the start of the warm-up operation is shown as time t1. As described with reference to FIG. 4, when the fuel cell 100 is frozen, the amount of electric charge generated by the fuel cell 100 is largely suppressed after the hydrogen remaining inside the fuel cell 100 is consumed at the time of starting. When performing the freeze determination, the freeze determination unit 220 of the present embodiment uses a predetermined reference time T in addition to the charge amount β that is the reference value of the generated charge amount.

  In step S120, if it is determined that the generated electric charge is less than the electric charge β which is the reference value (step S120: NO), the freezing determination unit 220 of the control unit 200 determines a predetermined reference time from the start of power generation (t1). It is determined whether (T) has elapsed (step S140). FIG. 6 shows a state in which the elapsed time (t2−t1) from the start of power generation at time t2 is the reference time T.

  If the reference time T has not elapsed (step S140: NO), the control unit 200 returns to step S120 and determines whether or not the generated charge amount is equal to or more than the reference value. The operation of steps S120 and S140 is repeated, and if it is determined in step S120 that the generated electric charge amount is equal to or more than the electric charge amount β before the reference time T elapses, the control unit 200 determines that the fuel cell 100 is in a frozen state. When it is determined that the vehicle has run out, the process proceeds to step S130 to enable the vehicle to run. When the state where the amount of generated electric charge is less than the amount of electric charge β has continued for the reference time T or more (step S140: YES), the freeze determination unit 220 of the control unit 200 determines that the fuel cell 100 is in a frozen state (step S150). ). In this case, the traveling determination unit 230 determines that traveling of the fuel cell 100 cannot be permitted, and the traveling control unit 240 stops the fuel cell system 30 (step S160), and terminates this routine.

  When stopping the fuel cell system 30 in step S160, the traveling control unit 240 maintains the state in which the above-described READY indicator is turned off. Then, a display is provided on a display or the like provided on the instrument panel to notify that the vehicle cannot run because the fuel cell system 30 has been stopped due to freezing.

  According to the present embodiment, as in the first embodiment, whether or not the fuel cell 100 is in a frozen state is determined based on the amount of charge generated by the fuel cell 100 after the warm-up operation is started according to the start instruction. Is determined to be frozen. As described above, the freezing determination is performed based on a phenomenon that actually occurs in the fuel cell 100 at the time of freezing, so that it is more accurate than in the case where the frozen state is indirectly estimated based on the temperature of the refrigerant circulating in the fuel cell 100 or the like. Can be determined, and the result can be reflected in the determination of travel permission.

  Furthermore, in the present embodiment, when the freeze determination unit 220 determines that the charge is free, when the state in which the generated charge is less than the charge amount β continues for the reference time T or more, it is determined that the state is the frozen state, and the generated charge amount is determined. When the charge reaches the charge amount β within the reference time T, it is determined that the vehicle is not in the frozen state. As described above, by performing the freezing determination based on the generated electric charge amount within the reference time T, the freezing determination can be performed more accurately than in the first embodiment. When the warm-up operation is performed in a state where the inside of the fuel cell 100 is frozen, although the output current is suppressed, the amount of electric charge generated from the start is gradually increased by continuing the minute power generation. . Therefore, even if the frozen state has not been eliminated, there is a possibility that the amount of electric charge generated from the start may be equal to or more than the reference value by continuing the warm-up operation for a long time. In the present embodiment, since it is also determined whether or not the fuel cell 100 is within the reference time at the time of the freeze determination, it is determined that the fuel cell 100 is not in a frozen state despite being frozen as described above. Can be suppressed.

C. Third embodiment:
FIG. 7 is an explanatory diagram showing the control unit 200 of the fuel cell vehicle 20 according to the third embodiment by using functional blocks representing some of the functions executed by the control unit 200. Since the fuel cell vehicle 20 of the third embodiment has the same configuration as the fuel cell vehicle 20 of the first embodiment shown in FIG. 1, common portions are denoted by the same reference numerals, and detailed description is omitted. .

  As shown in FIG. 7, the control unit 200 of the third embodiment includes, as functional blocks, the same charge detection unit 210, freeze determination unit 220, travel determination unit 230, travel control unit 240, power generation control as in the first embodiment. In addition to the section 250 and the output restricting section 260, a secondary battery detecting section 270 and an evacuation traveling determining section 280 are further provided. From the secondary battery monitor 173 described above, the secondary battery detection unit 270 sets the remaining capacity of the secondary battery 172 and the maximum output power allowed for the secondary battery 172 as the output enabled state of the secondary battery 172. A maximum output (secondary battery output Wout) that is a value is acquired. The evacuation traveling determination unit 280 acquires the remaining capacity of the secondary battery 172 and the output Wout of the secondary battery from the secondary battery detection unit 270, and determines whether or not the fuel cell vehicle 20 can perform the evacuation traveling. That is, based on the remaining capacity of the secondary battery 172 and the output Wout of the secondary battery, even when there is no output from the fuel cell 100, the fuel cell 100 is used only as a power source to reach the fuel cell to a safe place. It is determined whether or not the vehicle 20 can be evacuated. In order to determine whether evacuation traveling is possible, for example, a traveling distance required for general evacuation traveling is set, and such a distance is set such that the traveling is possible using only the secondary battery 172 as a power source. The minimum values of the remaining capacity of the battery 172 and the secondary battery output Wout may be set and stored in advance. If both the remaining capacity of the secondary battery 172 and the secondary battery output Wout are equal to or greater than the minimum value, it can be determined that the vehicle can be evacuated. In the present embodiment, both the remaining capacity of the secondary battery 172 and the output Wout of the secondary battery 172 are used to determine whether the vehicle can be evacuated, but only one of them may be used. That is, if one of them is equal to or larger than the predetermined minimum value, it may be determined that the vehicle can be evacuated.

  FIG. 8 is a flowchart showing a traveling permission / inhibition determination processing routine executed by CPU of control unit 200 when fuel cell vehicle 20 is started. The traveling permission / inhibition determination processing routine shown in FIG. 8 is executed instead of the traveling permission / inhibition determination processing routine of FIG. 3 in the first embodiment.

  When a start instruction is input by operating the start switch 25 and this routine is started, the CPU of the control unit 200 starts the warm-up operation of the fuel cell 100 (step S200), and then starts the fuel cell 100 operation. It is determined whether the temperature is below the freezing point (step S210). The processing in steps S200 and S210 is the same as the processing in steps S100 and S110 in FIG.

  If it is determined in step S210 that the temperature of fuel cell 100 is below the freezing point (step S210: YES), control unit 200 determines whether fuel cell vehicle 20 is capable of evacuating (step S220). The operation in step S220 is performed by the evacuation traveling determination unit 280 as described above. When it is determined in step S210 that the temperature of the fuel cell 100 exceeds the freezing point (step S210: NO), the traveling determination unit 230 of the control unit 200 determines that traveling of the fuel cell 100 can be permitted. Then, the travel control unit 240 sets the fuel cell vehicle 20 in a travelable state (step S260), and terminates this routine. Step S260 will be described later.

  If it is determined in step S220 that evacuation travel is possible (step S220: YES), travel determination section 230 of control section 200 determines that travel of fuel cell 100 can be permitted, and travel control section 240 can travel fuel cell vehicle 20. The state is set (step S230). Specifically, in step S230, traveling control unit 240 turns on the READY indicator to notify the driver that fuel cell vehicle 20 can travel. Then, travel control section 240 starts control for performing travel using at least secondary battery 172 as a power supply. At this time, when the fuel cell 100 is in a frozen state, or when the temperature of the fuel cell 100 has not reached the steady-state temperature range and the warm-up operation has not been completed, the fuel cell 100 Output is suppressed. If the warm-up operation of the fuel cell 100 has been completed, normal traveling using the output of the fuel cell 100 becomes possible.

  When the fuel cell vehicle 20 is enabled to travel in step S230, the control unit 200 determines whether the inside of the fuel cell 100 is frozen (step S240), and determines that the fuel cell 100 is not frozen (step S240: NO), this routine ends. Thereafter, the fuel cell vehicle 20 can continue running according to the warm-up state. When it is determined in step S240 that the vehicle is in a frozen state (step S240: YES), the process of step S240 is performed again. As described above, since the warm-up operation has been started in step S200 at the time of startup, the temperature of the fuel cell 100 gradually rises with the warm-up operation, and the frozen state may eventually be eliminated. Control unit 200 repeats step S240 until it is determined that it is not in the frozen state.

  The operation of step S240 is performed by freeze determination section 220. The operation of the freeze determination in step S240 can be, for example, similar to step S120 in the first embodiment. That is, the amount of generated electric charge of the fuel cell 100 obtained by integrating the product of the output current of the fuel cell 100 and the time after the start instruction is input to the fuel cell vehicle 20, and a predetermined reference value What is necessary is just to compare with a certain charge amount β. When the generated electric charge of the fuel cell 100 is equal to or more than the electric charge β, it is determined that the fuel cell 100 is not frozen. When the generated electric charge of the fuel cell 100 is less than the electric charge β, the fuel cell 100 What is necessary is just to determine that it is frozen. However, the determination of freezing in step S240 may be performed by a method other than the method using the amount of charge generated by the fuel cell 100. For example, whether the inside of the fuel cell 100 is frozen may be estimated based on the temperature of the fuel cell 100 detected by the temperature sensor 105, specifically, the temperature of the refrigerant discharged from the fuel cell 100 or the like. .

  When the evacuation traveling determination unit 280 determines that the evacuation traveling is not possible in step S220 (step S220: NO), the freezing determination unit 220 of the control unit 200 determines whether the inside of the fuel cell 100 is frozen (step S220). S250). The operation in step S250 is the same as the operation in step S240 described above. When it is determined in step S250 that fuel cell 100 is in a frozen state (step S250: YES), travel determination unit 230 determines that travel of fuel cell vehicle 20 cannot be permitted, and freeze determination unit 220 determines that fuel cell 100 is in a frozen state. Until it is determined that is not frozen, the operation of step S250 is repeated. When it is determined in step S250 that fuel cell 100 is not in a frozen state (step S250: NO), travel determination unit 230 determines that travel of fuel cell vehicle 20 can be permitted, and travel control unit 240 determines that fuel cell vehicle 20 Is set in a runnable state (step S260), and this routine ends.

  In step S260, the travel control unit 240 turns on the READY indicator to notify the driver that the fuel cell vehicle 20 can travel. Then, the traveling control unit 240 starts control for performing traveling using at least the fuel cell 100 as a power supply in accordance with a load request based on the accelerator opening and the like. However, until the temperature of the fuel cell 100 reaches a predetermined temperature range as a steady state, the fuel cell 100 performs power generation giving priority to heat generation, thereby controlling the output of the fuel cell 100 to be suppressed. In addition, the secondary battery 172 is charged as the fuel cell 100 generates power.

  According to the present embodiment, when it is determined that the fuel cell vehicle 20 can perform the limp-home run, the fuel cell vehicle 20 is set in the runnable state without performing the freeze determination whether the fuel cell 100 is in the frozen state. I have. That is, if the fuel cell vehicle 20 is capable of the limp-home run, the fuel cell vehicle 20 can be made to travel immediately without waiting for the freeze determination to end. Therefore, even when the fuel cell vehicle 20 is started under a low-temperature condition, a time lag that occurs until the fuel cell vehicle 20 can actually run can be suppressed. At this time, since it is confirmed that the fuel cell vehicle 20 can perform the limp-home operation, even if there is any trouble in the warm-up operation of the fuel cell 100 after the vehicle starts running, the fuel cell Power generation can be stopped and evacuation travel can be performed.

  Further, in steps S240 and S250 of the present embodiment, similar to the first embodiment, when the freeze determination is performed based on the amount of charge generated by the fuel cell 100 after the warm-up operation is started by the start instruction. Can more accurately determine freezing than when indirectly estimating a frozen state. This is for determining freezing on the basis of a phenomenon that actually occurs in the fuel cell 100 during freezing due to a shortage of hydrogen supply due to freezing.

D. Fourth embodiment:
FIG. 9 is a flowchart illustrating a running permission / inhibition determination processing routine executed by control unit 200 of fuel cell vehicle 20 when starting fuel cell vehicle 20 of the fourth embodiment. The fuel cell vehicle 20 according to the fourth embodiment has the same configuration as the fuel cell vehicle 20 according to the first embodiment shown in FIG. 1, and the control unit 200 according to the fourth embodiment uses the third configuration shown in FIG. Since the control unit 200 has the same configuration as that of the control unit 200 according to the embodiment, the same reference numerals are given to the same parts as those of the control unit 200, and the detailed description will be omitted. The traveling permission / inhibition determination processing routine shown in FIG. 9 is executed instead of the traveling permission / inhibition determination processing routine of FIG. 3 in the first embodiment. In FIG. 9, steps common to those in FIG. 8 are denoted by the same step numbers, and detailed description is omitted.

  When a start instruction is input by operating the start switch 25 and this routine is started, the CPU of the control unit 200 starts the warm-up operation of the fuel cell 100 (step S200), and then starts the fuel cell 100 operation. It is determined whether the temperature is below the freezing point (step S210). If it is determined in step S210 that the temperature of fuel cell 100 is below the freezing point (step S210: YES), control unit 200 determines whether fuel cell vehicle 20 is capable of evacuating (step S220). If it is determined in step S210 that the temperature of fuel cell 100 is above the freezing point (step S210: NO), travel determination unit 230 of control unit 200 determines that travel of fuel cell 100 can be permitted. The determination is made, and the travel control unit 240 sets the fuel cell vehicle 20 in a travelable state (step S260), and ends this routine.

  If it is determined in step S220 that evacuation travel is possible (step S220: YES), travel determination section 230 of control section 200 determines that travel of fuel cell 100 can be permitted, and travel control section 240 controls fuel cell vehicle 20. The vehicle is brought into a runnable state (step S230). When the fuel cell vehicle 20 is enabled to travel in step S230, the control unit 200 determines whether the inside of the fuel cell 100 is frozen (step S240), and determines that the fuel cell 100 is not frozen (step S240: NO), this routine ends. When it is determined in step S240 that the vehicle is in the frozen state (step S240: YES), the traveling control unit 240 of the control unit 200 stops the fuel cell system 30 (step S242), and outputs only the output power from the secondary battery 172. The state where the used limp-home mode can be performed is set (step S244), and the routine ends. In the present embodiment, at the time of evacuation traveling, control is performed in which the output of the motor 170 is suppressed in response to a load request based on the accelerator opening and the like.

  The freeze determination in step S240 of the present embodiment can be, for example, the same as that of step S120, step S140, and step S150 of the second embodiment. That is, in step S240, the freeze determination unit 220 compares the generated electric charge amount of the fuel cell 100 after the start instruction is input to the fuel cell vehicle 20 and the electric charge amount β that is a predetermined reference value, Just compare. When the state in which the generated electric charge is less than the electric charge β continues for a predetermined reference time T or more, it is determined that the fuel cell 100 is in a frozen state, and the generated electric charge becomes less than the electric charge β within the reference time T. Is reached, it may be determined that the fuel cell 100 is not in a frozen state. However, the determination of freezing in step S240 may be performed by a method other than the method using the amount of charge generated by the fuel cell 100. For example, whether the inside of the fuel cell 100 is frozen may be estimated based on the temperature of the fuel cell 100 detected by the temperature sensor 105, specifically, the temperature of the refrigerant discharged from the fuel cell 100 or the like. .

  When the evacuation traveling determination unit 280 determines that the evacuation traveling is not possible in step S220 (step S220: NO), the freezing determination unit 220 of the control unit 200 determines whether the inside of the fuel cell 100 is frozen (step S220). S250). The operation in step S250 is the same as the operation in step S240 described above. When it is determined in step S250 that fuel cell 100 is in a frozen state (step S250: YES), travel determination unit 230 determines that travel of fuel cell vehicle 20 cannot be permitted, and travel control unit 240 determines that fuel cell system 30 Is stopped (step S255), and this routine ends. When stopping the fuel cell system 30 in step S255, the traveling control unit 240 maintains the state in which the above-described READY indicator is turned off. Then, a display is provided on a display or the like provided on the instrument panel to notify that the vehicle cannot run because the system has been stopped due to freezing.

  When it is determined in step S250 that fuel cell 100 is not in a frozen state (step S250: NO), travel determination unit 230 determines that travel of fuel cell vehicle 20 can be permitted, and travel control unit 240 determines Is set in a runnable state (step S260), and this routine ends. In step S260, the travel control unit 240 turns on the READY indicator to notify the driver that the fuel cell vehicle 20 can travel. Then, the traveling control unit 240 starts control for performing traveling using at least the fuel cell 100 as a power supply in accordance with a load request based on the accelerator opening and the like. However, until the temperature of the fuel cell 100 reaches a predetermined temperature range as a steady state, the fuel cell 100 performs power generation giving priority to heat generation, thereby controlling the output of the fuel cell 100 to be suppressed. In addition, the secondary battery 172 is charged as the fuel cell 100 generates power.

  According to the present embodiment, when it is determined that the fuel cell vehicle 20 can perform the limp-home run, the fuel cell vehicle 20 is set in the runnable state without performing the freeze determination whether the fuel cell 100 is in the frozen state. I have. That is, if the fuel cell vehicle 20 is capable of the limp-home run, the fuel cell vehicle 20 can be made to travel immediately without waiting for the freeze determination to end. Therefore, similarly to the third embodiment, even when the fuel cell vehicle 20 is started under a low temperature condition, it is possible to suppress a time lag that occurs until the fuel cell vehicle 20 becomes in a state where the fuel cell vehicle 20 can actually run. . At this time, since it is confirmed that the fuel cell vehicle 20 is able to perform the limp-home run, if it is determined that the fuel cell 100 is frozen after the vehicle starts running, the power generation of the fuel cell 100 is stopped. Then, the evacuation traveling can be performed.

  Further, in steps S240 and S250 of the present embodiment, similar to the second embodiment, when the freezing determination is performed based on the amount of electric charge generated by the fuel cell 100 after the warm-up operation is started by the start instruction. By performing freezing determination based on a phenomenon actually occurring in the fuel cell 100 during freezing, freezing determination can be performed more accurately than when indirectly estimating a frozen state. Furthermore, in the present embodiment, when the freeze determination unit 220 determines that the charge is free, when the state in which the generated charge is less than the charge amount β continues for the reference time T or more, it is determined that the state is the frozen state, and the generated charge amount is determined. When the charge reaches the charge amount β within the reference time T, it is determined that the vehicle is not in the frozen state. As described above, by performing the freeze determination based on the amount of generated electric charge within the reference time T, the freeze determination can be performed more accurately than in the third embodiment. This is because, by continuing the warm-up operation for a long time, it is possible to prevent the amount of generated electric charge from the time of starting from being equal to or more than the reference value, and to suppress the determination that the vehicle is not in a frozen state despite being in a frozen state.

  The present invention is not limited to the above-described embodiment, and can be implemented with various configurations without departing from the spirit thereof. For example, the technical features of the embodiments corresponding to the technical features in each embodiment described in the summary of the invention may be used to solve some or all of the above-described problems, or to provide some of the above-described effects. Or, in order to achieve all of them, replacement and combination can be appropriately performed. Unless the technical features are described as essential in the present specification, they can be deleted as appropriate.

Reference Signs List 20: fuel cell vehicle, 22: body, 25: start switch, 30: fuel cell system, 100: fuel cell, 102: voltage sensor, 103: current sensor, 104: DC / DC converter, 105: temperature sensor, 110: Hydrogen tank, 120: hydrogen gas supply unit, 121: hydrogen supply channel, 122: circulation channel, 123: hydrogen release channel, 124: open / close valve, 125: pressure reducing valve, 126: hydrogen supply device, 127: circulation pump , 128 pressure sensor, 129 opening / closing valve, 130 compressor, 140 air supply unit, 141 first air flow path, 142 air release flow path, 143 back pressure valve, 144 flow dividing valve, 145 flow 2 air flow path, 146 third air flow path, 147 flow rate sensor, 170 motor, 172 secondary battery, 173 secondary battery monitor, 17 ... DC / DC converter, 178 ... wiring, 180 ... accelerator opening sensor, 200 ... control unit, 210 ... charge detection unit, 220 ... freezing determination unit, 230 ... travel determination unit, 240 ... travel control unit, 250 ... power generation control Unit, 260: output limiting unit, 270: secondary battery detection unit, 280: evacuation traveling determination unit

Claims (1)

A fuel cell vehicle equipped with a fuel cell,
A temperature sensor capable of measuring the temperature of the fuel cell,
When the output voltage of the fuel cell drops below the target voltage, an output limiting unit that limits the output current of the fuel cell,
A control unit for controlling a running state of the fuel cell vehicle;
With
The control unit includes:
When a start instruction is input to the fuel cell vehicle, power generation of the fuel cell is started, and the fuel cell after the start instruction is input using an output current of the fuel cell. The amount of charge generated in
When the temperature of the fuel cell detected by the temperature sensor is below the freezing point, and when the amount of generated electric charge is less than a predetermined reference value, it is determined that traveling of the fuel cell vehicle cannot be permitted,
When the temperature of the fuel cell detected by the temperature sensor exceeds the freezing point, and when the temperature of the fuel cell detected by the temperature sensor is below the freezing point, and the generated electric charge is equal to or more than the reference value, The fuel cell vehicle according to claim 1, wherein the fuel cell vehicle is set in a running state.

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