JP2019067684A - Fuel cell system - Google Patents

Abstract

To provide a fuel cell system that specifies an abnormal portion of a water supply system and improves maintainability.SOLUTION: A control device 15 of a fuel cell system, reduces a water surface of modification water in a water supply pipe 11b by inversely rotating a modification water pump 11b1 to a first return water level, and after that, normally rotates the modification water pump 11b1 for a driving command time in accordance with a return amount of the modification water by a first modification water level adjustment, and increases the water surface of the modification water in the water supply pipe 11b from the first return water level. At the time, the control device 15 measures a time required for reaching a reference water level from the first return water level of the water surface of the modification water in the water supply pipe 11b as an actual measurement time by using a detection result of a water level sensor 11b2 (a measurement part). The control device 15 determines failure of the water supply pipe 11b and the modification water pump 11b1 on the basis of a relationship between the driving command time and the actual measurement time (a determination part).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fuel cell system.

  As one type of fuel cell system, one disclosed in Patent Document 1 is known. As shown in FIG. 1 of Patent Document 1, the fuel cell system includes an evaporation unit 2, a reforming unit 3, a water tank 4, a water supply passage 8, a water conveyance source 8A, and a water sensor 87. The control unit 100 executes a water supply abnormality determination process for water supply to the evaporation unit 2. In the water supply abnormality determining process, the water transport source 8A is operated to return the reformed water in the water feed passage 8 to the water tank 4 by reversely rotating the water transport source 8A, and in the state where the reformed water in the water feed passage 8 is emptied. Water supply operation to supply the reformed water of the water tank 4 to the water supply passage 8 by rotating forwardly, and detecting a physical quantity related to the output of the water transport source 8A until the water sensor 87 detects water; Is out of the specified range, the determination operation of determining that the water supply to the evaporation unit 2 is abnormal is included.

JP, 2013-191319, A

  Although the fuel cell system described in Patent Document 1 described above carries out the water supply abnormality determination, there is room for improvement in identifying an abnormal part of the water supply system provided from the water tank to the reforming unit, As a result, there is room to improve maintainability.

  The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to identify an abnormal part of a water supply system in a fuel cell system and to improve maintainability.

  In order to solve the above-described problems, the invention of a fuel cell system according to claim 1 is a fuel cell that generates electric power using a fuel and an oxidant gas, and a fuel cell that generates a fuel from a reforming material and reforming water. And a combustion unit that introduces combustible gas including unused fuel from the fuel cell and burns with oxidant gas to lead out the combustion exhaust gas, and heat between the combustion exhaust gas and the heat medium A heat exchanger that exchanges the water vapor contained in the combustion exhaust gas to generate condensed water and stores the condensed water supplied from the heat exchanger as reforming water and supplies it to the reforming unit A water tank, a water supply pipe for supplying reforming water from the water tank to the reforming unit, and a reforming water delivery device provided in the water supply pipe for delivering the reforming water in the water tank to the reforming unit; A reformed water return device provided in the water feed pipe for returning the reformed water in the water feed pipe back to the water tank; A fuel cell system comprising a water level sensor provided in the supply pipe for detecting whether the water surface of the reformed water in the water supply pipe is at the reference water level, and controlling the power generation of the fuel cell. And the control device operates the reforming water return device to lower the water surface of the reforming water in the water supply pipe from the initial water level to the first return water level lower than the initial water level. After performing the first reforming water level adjustment by the first reforming water level adjustment control unit performing the water level adjustment and the first reforming water level adjustment control unit, the reforming water by the first reforming water level adjustment The second reforming water level adjustment is performed to raise the water surface of the reforming water in the water supply pipe from the first return water level by commanding to drive the reforming water delivery device for the drive command time corresponding to the return amount 2 Reformed water level adjustment control unit and second reformed water by second reformed water level adjustment control unit A measurement unit that measures the time taken for the water surface of the reformed water in the water supply pipe to reach from the first return water level to the reference water level using the detection results of the water level sensor when performing position adjustment as a measurement time And a determination unit that determines a failure of the water supply pipe and the reformed water delivery apparatus based on the relationship between the drive command time and the actual measurement time measured by the measurement unit.

  According to this, the control device operates the reforming water return device to lower the water surface of the reforming water in the water supply pipe to the first return water level (first reforming water level adjustment), and then the first (1) Drive the reforming water delivery device for the drive command time corresponding to the amount of reforming water return due to the reforming water level adjustment, and raise the water surface of the reforming water in the water supply pipe from the first return water level (second Reformed water level adjustment). At this time, the control device measures the time taken for the water surface of the reformed water in the water supply pipe to reach from the first return water level to the reference water level using the detection result of the water level sensor as measurement time (measurement Department). Then, the control device determines a failure of the water supply pipe and the reformed water delivery device based on the relationship between the drive command time and the actual measurement time measured by the measurement unit (determination unit). As a result, in the fuel cell system, it is possible to specify an abnormal part of the water supply system provided from the water tank to the reforming unit, and consequently, maintainability can be improved.

FIG. 1 is a schematic view showing an overview of an embodiment of a fuel cell system according to the present invention. It is a flowchart of the control program run by the control apparatus shown in FIG. It is a flowchart of the control program run by the control apparatus shown in FIG. It is a figure which shows the relationship between detection time t2 and constant (beta). It is a figure which shows the relationship between drive instruction | command time and detection time t4, and the relationship between the normal range of a water supply system, and a failure range. It is a schematic diagram showing an outline of a modification of one embodiment of a fuel cell system by the present invention. 7 is a flowchart of a control program executed by the control device shown in FIG. 7 is a flowchart of a control program executed by the control device shown in FIG. It is a figure which shows the relationship between time t5 and time t6.

  Hereinafter, an embodiment of a fuel cell system 1 according to the present invention will be described. As shown in FIG. 1, the fuel cell system 1 includes a power generation unit 10 and a hot water storage tank 21. The power generation unit 10 includes a housing 10 a, a fuel cell module 11 (30), a heat exchanger 12, an inverter device 13, a water tank 14, and a control device 15. The fuel cell module 11 (30), the heat exchanger 12, the inverter device 13, the water tank 14, and the control device 15 are accommodated in a housing 10a.

  The fuel cell module 11 includes at least a fuel cell 34 as described later. The fuel cell module 11 is supplied with a reforming material, reforming water and cathode air. Specifically, one end of the fuel cell module 11 is connected to the supply source Gs, and the other end of the reforming material supply pipe 11a to which the reforming material is supplied is connected. The raw material supply pipe 11a for reforming is provided with a raw material pump 11a1. Further, one end of the fuel cell module 11 is connected to the water tank 14, and the other end of the water supply pipe 11b to which the reforming water is supplied is connected. Furthermore, in the fuel cell module 11, one end is connected to the cathode air blower 11c1 and the other end of the cathode air supply pipe 11c to which cathode air is supplied is connected.

  The water supply pipe 11b is provided with a reforming water pump 11b1. The reforming water pump 11b1 sucks in the reforming water of the water tank 14 and sends it to the evaporating unit 32 (reforming unit 33) (forward rotation: reforming water delivery) and the evaporating unit 32 from the reforming water pump 11b1. This pump is configured to be able to suction the reformed water in the water supply pipe 11b on the (reforming section 33) side and switch the delivery to the water tank 14 (reverse rotation: reformed water return). The reforming water pump 11b1 is a reforming water delivery device provided in the water supply pipe 11b and delivering the reforming water in the water tank 14 to the reforming unit 33. The reforming water pump 11b1 is provided in the water supply pipe 11b. This is a reforming water return device that returns the reforming water in 11b to the water tank 14.

  The water supply pipe 11b is provided with a water level sensor 11b2 for detecting whether the water surface of the reformed water in the water supply pipe 11b is at the reference water level. The detection result of the water level sensor 11 b 2 is to be transmitted to the control device 15. The water level sensor 11 b 2 is provided downstream of the reforming water pump 11 b 1 and upstream of the evaporation unit 32. It is preferable that the water level sensor 11b2 be disposed immediately before or at the same height as the inlet port of the evaporation section 32 in the water supply pipe 11b. The detection principle of the water level sensor 11b2 may be anything, a method of detecting a change in capacitance based on the presence or absence of water, a method of detecting a change in amount of energization based on the presence or absence of water, a change of electrical resistance based on the presence or absence of water It may be any method such as a method of detection, a method of detecting a change in water pressure based on the presence or absence of water, a method of detecting a change in magnetism based on the presence or absence of water, or any other method. The detection unit of the water level sensor 11b2 is preferably disposed at the same height as the reference water level. In addition, the detection unit of the water level sensor 11b2 may be disposed at a position spaced apart from the reference water level by a predetermined distance in the vertical direction. The reference water level is the water level of the reforming water to which the reforming water is supplied to the evaporation unit 32 without delay when the reforming water pump 11b1 rotates forward. As shown in FIG. 1, in the water supply pipe 11b, the water tank 14, the reforming water pump 11b1, the water level sensor 11b2, and the evaporation unit 32 are arranged in series in this order.

  The heat exchanger 12 is supplied with the combustion exhaust gas exhausted from the fuel cell module 11 and also supplied with the stored hot water from the hot water storage tank 21, and contains exhaust heat from the combustion exhaust gas (the fuel cell 34 and the reforming unit 33 Heat exchange between the storage water and the storage water). Further, the heat exchanger 12 performs heat exchange between the combustion exhaust gas and the stored hot water, condenses the water vapor contained in the combustion exhaust gas, and generates condensed water. The stored hot water is a heat medium (exhaust heat recovered water) that recovers the exhaust heat of the combustion exhaust gas.

  The hot water storage tank 21 stores hot water storage, and is connected to a hot water circulation line 22 through which the hot water circulates (circulates in the direction of the arrow in the figure). A radiator 22a, a stored water circulation pump 22b, and a heat exchanger 12 are disposed on the stored water circulation line 22 in order from the lower end to the upper end.

  The heat exchanger 12 includes a casing 12b. An exhaust pipe 11 d from the fuel cell module 11 is connected to an upper portion of the casing 12 b. An exhaust pipe 11e connected to the outside (atmosphere) is connected to the lower part of the casing 12b. The condensed water supply pipe 12a connected to the water tank 14 is connected to the bottom of the casing 12b. In the casing 12b, a flue gas passage (not shown) through which the flue gas passes is formed. The heat exchange part (condensing part) 12c connected to the stored hot water circulation line 22 is disposed in the combustion exhaust gas flow path. The stored hot water flows in the heat exchange unit 12c, and the combustion exhaust gas flows outside the heat exchange unit 12c. Preferably, the stored hot water and the combustion exhaust gas are configured to flow in opposite directions to each other.

  In the heat exchanger 12 configured as described above, the combustion exhaust gas from the fuel cell module 11 is introduced into the casing 12b through the exhaust pipe 11d, and the hot water storage water passes through the heat exchanger 12c through which the hot water flows. Heat exchange with water takes place to condense and cool. Thereafter, the combustion exhaust gas is discharged to the outside through the exhaust pipe 11e. In addition, the condensed water condensed is supplied to the water tank 14 through the condensed water supply pipe 12a (drops by its own weight). On the other hand, the stored hot water flowing into the heat exchange unit 12c is heated and flows out.

An exhaust heat recovery system 20 is configured from the heat exchanger 12, the hot water storage tank 21 and the hot water storage water circulation line 22 described above. The exhaust heat recovery system 20 recovers and stores exhaust heat of the fuel cell module 11 in stored hot water.
The hot water storage tank 21 is a sealed container. The hot water storage tank 21 is a pressure-resistant container. The temperature distribution in the hot water storage tank 21 is basically divided into two layers having different temperatures. The upper layer is a relatively high temperature layer (for example, 50 ° C. or more), and the lower layer is a relatively low temperature layer (for example, 20 ° C. or less (the temperature of tap water)). The upper and lower layers are at substantially the same temperature.

The radiator 22a is a cooling device for cooling the heat medium (stored water) circulating in the stored water circulation line 22 and is on / off controlled by a command of the control device 15, and cools the heat medium in the on state to turn it off. It is not cooled when it is in the state. The radiator 22a includes a heat exchange unit (not shown) that exchanges heat between the heat medium and the air, and a cooling fan (not shown) that cools the heat exchange unit.
The hot water storage water circulation pump 22b is a delivery device for delivering the heat medium (stored hot water) of the hot water storage water circulation line 22 and circulating it in the direction of the arrow, and controlled by the control device 15 to control its discharge amount (delivery amount). It is supposed to be.

  The inverter device 13 receives the DC voltage output from the fuel cell 34, converts it into a predetermined AC voltage, and supplies it to the power supply line 16b connected to the AC system power supply 16a and the external power load 16c (for example, an electric appliance). Output. In addition, the inverter device 13 receives an AC voltage from the system power supply 16a via the power supply line 16b, converts the voltage into a predetermined DC voltage, and outputs the voltage to auxiliary equipment (such as pumps and blowers) and the control device 15.

  The water tank 14 stores condensed water supplied from the heat exchanger 12 and supplies the condensed water to the evaporation unit 32 and further to the reforming unit 33 as reforming water. In the water tank 14, a water amount sensor 14a for detecting the amount of water in the water tank 14 (water level: hereinafter, also referred to as tank water amount) is disposed. The detection result of the water amount sensor 14 a is output to the control device 15. The water amount sensor 14a is, for example, a float type sensor, and is a sensor of a type that converts the amount of vertical movement of the float into a resistance value by a variable resistance (potentiometer) and displays the amount of water (remaining water amount) by vertical movement of the resistance value. .

  Moreover, the water purifier 40 is provided in the condensed water supply pipe 12a. The water purifier 40 purifies the condensed water supplied from the heat exchanger 12 using, for example, an ion exchange resin, and delivers the purified water to the water tank 14. The water tank 14 may be configured to purify the condensed water with an ion exchange resin. In this case, the water purifier 40 can be omitted.

The fuel cell module 11 (30) includes a casing 31, an evaporation unit 32, a reforming unit 33, and a fuel cell 34. The casing 31 is formed of a heat insulating material in a box shape.
The evaporation unit 32 is heated by a combustion gas described later, evaporates the supplied reforming water to generate steam, and preheats the supplied reforming raw material. The evaporation unit 32 mixes the water vapor thus generated and the preheated reforming raw material and supplies the mixture to the reforming unit 33. As the reforming material, there are natural gas (mainly methane gas), gaseous fuel for reforming such as LP gas, kerosene, gasoline, liquid fuel for reforming such as gasoline, methanol, etc. In this embodiment, natural gas Explain.

  The evaporation unit 32 is connected to the other end of the water supply pipe 11 b whose one end (lower end) is connected to the water tank 14. Further, the reforming unit 32 is connected to a reforming raw material supply pipe 11 a whose one end is connected to the supply source Gs. The supply source Gs is, for example, a gas supply pipe of city gas, a gas cylinder of LP gas. The evaporation unit 32 is provided with a temperature sensor 32 a that detects the temperature of the evaporation unit 32 (for example, the inside of the evaporation unit 32). The detection result of the temperature sensor 32a is transmitted to the control device 15.

  The reforming unit 33 is heated by the above-described combustion gas and supplied with heat necessary for the steam reforming reaction, so that the reformed gas from the mixed gas (reforming raw material, steam) supplied from the evaporating unit 32 is generated. Are generated and derived. The reforming unit 33 is filled with a catalyst (for example, Ru or Ni-based catalyst), and the mixed gas is reacted by the catalyst and reformed to generate a gas containing hydrogen gas and carbon monoxide. (So-called steam reforming reaction). The reformed gas includes hydrogen, carbon monoxide, carbon dioxide, steam, natural gas not reformed (methane gas), reformed water not used for reforming (steam). Thus, the reforming unit 33 generates a reformed gas (fuel) from the reforming raw material (raw fuel) and the reforming water, and supplies the reformed gas (fuel) to the fuel cell 34. The steam reforming reaction is an endothermic reaction.

  The fuel cell 34 is configured by stacking a plurality of cells 34 a composed of a fuel electrode, an air electrode (oxidizer electrode), and an electrolyte interposed between the two electrodes. The fuel cell of the present embodiment is a solid oxide fuel cell, and uses zirconium oxide, which is a type of solid oxide, as an electrolyte. The fuel electrode of the fuel cell 34 is supplied with hydrogen, carbon monoxide, methane gas or the like as a fuel. The operating temperature is about 400 to 1000 ° C.

  On the fuel electrode side of the cell 34a, a fuel flow passage 34b through which the reformed gas, which is a fuel, flows is formed. On the air electrode side of the cell 34a, an air flow path 34c through which air (cathode air), which is an oxidant gas, flows is formed.

  The fuel cell 34 is provided on the manifold 35. The reformed gas (anode gas) from the reforming unit 33 is supplied to the manifold 35 via the reformed gas supply pipe 38. The lower end (one end) of the fuel flow passage 34b is connected to the fuel outlet of the manifold 35, and the reformed gas led out from the fuel outlet is introduced from the lower end and derived from the upper end. . The cathode air delivered by the cathode air blower 11c1 is supplied via the cathode air supply pipe 11c, introduced from the lower end of the air flow path 34c and drawn out from the upper end.

In the fuel cell 34, power generation is performed by the anode gas supplied to the fuel electrode and the oxidant gas (cathode gas) supplied to the air electrode. That is, in the fuel electrode, reactions shown in the following chemical formula 1 and chemical formula 2 occur, and in the air electrode, a reaction shown in chemical formula 3 below occurs. That is, oxide ions (O ²⁻ ) generated at the air electrode permeate the electrolyte, and react with hydrogen at the fuel electrode to generate electric energy. Therefore, the reformed gas and the oxidant gas (air) not used for power generation are led out from the fuel flow path 34 b and the air flow path 34 c.
(Formula 1)
H ₂ + O ^2- → H ₂ O + 2 e ⁻
(Formula 2)
CO + O ^2- → CO ₂ + 2 e ⁻
(Formula 3)
^{_{1 / 2O 2 + 2e - →}} O 2-

  Then, the reformed gas (anode off gas) which has not been used for power generation is led from the fuel flow passage 34b to the combustion space 36 (formed between the fuel cell 34 and the evaporation unit 32 (reforming unit 33)). . An oxidant gas (air: cathode off gas) not used for power generation is led out from the air flow path 34 c to the combustion space 36. The anode off gas is combusted by the cathode off gas in the combustion space 36, and the evaporation portion 32 and the reforming portion 33 are heated by the combustion gas. Furthermore, the inside of the fuel cell module 11 is heated to the operating temperature. Thereafter, the combustion gas is exhausted from the exhaust pipe 11e provided at the lower part of the casing 12b to the outside of the fuel cell module 11 as combustion exhaust gas. As described above, the combustion space 36 introduces a flammable gas (anode off gas) including the unused fuel (reformed gas) from the fuel cell 34 and burns with the oxidant gas to generate the combustion exhaust gas (including water vapor). It is a combustion part to derive.

  In the combustion section 36, the anode off gas is burned to generate a flame 37 (combustion gas). The combustion unit 36 is provided with a pair of ignition heaters 36a1 and 36a2 for igniting the anode off gas.

  The control device 15 drives the accessory to control the operation of the fuel cell system 1 in an integrated manner. The controller 15 can control the fuel cell 34 to generate power. The control device 15 has a microcomputer (not shown). The microcomputer comprises an input / output interface, a CPU, a RAM and a ROM (all not shown) connected respectively via a bus. The CPU carries out integrated operation of the fuel cell system 1. The RAM temporarily stores variables necessary for the execution of the control program, and the ROM stores the control program.

Next, the operation of the fuel cell system 1 described above will be described along the flowcharts shown in FIGS. 2 and 3. The control device 15 executes a program in accordance with the flowchart.
In step S102, the control device 15 determines whether the water level sensor 11b2 detects absence of water based on the detection result of the water level sensor 11b2. If the water level of the reforming water is in the detection portion of the water level sensor 11b2, the presence of water is detected, and if the water level of the reforming water is below the detection portion of the water level sensor 11b2, the water absence is detected. If the controller 15 detects the presence of water, it ends the program once, and if it detects the absence of water, it proceeds the program to step S104 and subsequent steps.
Note that, instead of the process of step S102, it may be determined whether or not it is necessary to determine a failure point. For example, it may be determined whether or not a failure point determination switch indicating a failure point determination instruction has been pressed.
Also, the water absence detection by the water level sensor 11b2 is normal when the sensor itself is normal but the water level of reformed water is actually lower than the detection unit, or the water level of reformed water is actually in the detection unit but the sensor itself is broken Including the case.

In step S104, the controller 15 operates (reverse rotation) the reforming water pump 11b1 as the reforming water return device to lower the water surface of the reforming water in the water supply pipe 11b from the initial water level to the initial water level. The first reformed water level adjustment is performed to reduce the position to the first return water level (first reformed water level adjustment control unit). Specifically, the control device 15 starts the reverse rotation of the reforming water pump 11b1, and continues the reverse rotation for a time t1 at a flow rate of αcc / min. As a result, the reformed water in the water supply pipe 11 b downstream of the reformed water pump 11 b 1 is returned to the water tank 14.
The time t1 is preferably set to a time in which the entire amount (equal to the piping volume) of the reforming water from the evaporation part 32 of the water supply pipe 11b to the reforming water pump 11b1 can be delivered. α is a delivery flow rate per unit time of the reforming water pump 11b1, and is, for example, a maximum delivery flow rate.
The initial water level is the surface of the reformed water just before the first reformed water level adjustment (water level at the start of the first reformed water level adjustment), and if it is the reference water level, the water level lower than the reference water level Sometimes. The first return water level may be located below the initial water level, and may be located above the reforming water pump 11b1, or below the reforming water pump 11b1.

In step S106, the controller 15 controls the water amount sensor within a period of time t1 from when the first reforming water level adjustment is started (from when the first reforming water level adjustment is started to when the time t1 elapses). It is determined whether an increase in a predetermined amount of water has been detected from the time when the first reforming water level adjustment has been started by 14a. The predetermined amount of water is preferably set to a value larger than the total amount of reforming water from the evaporation section 32 of the water supply pipe 11b to the reforming water pump 11b1. In the case where the water supply pipe 11b from the water level sensor 11b2 to the evaporation unit 32 is horizontal or inclined downward, the predetermined water amount is the reformed water from the water level sensor 11b2 to the reforming water pump 11b1. It is preferable to set to a value larger than the total amount of The control device 15 detects an increase in the predetermined water amount if the remaining amount of reformed water in the water tank 14 exceeds the predetermined water amount based on the detection result of the water amount sensor 14a, and does not detect the increase in the predetermined water amount if it exceeds.
Further, in step S106, the control device 15 measures a time (detection time) t2 taken from when the first reformed water level adjustment is started to when the water amount sensor 14a detects an increase in the predetermined water amount. For example, time t1 is a value obtained by dividing the predetermined amount of water mentioned above by the amount of return (amount of delivery) per unit time of the reforming water pump 11b1 (a value obtained by considering the delivery capacity of the reforming water pump 11b1 It is set to the value which added).

  If water quantity sensor 14a detects an increase in the predetermined water quantity within time t1 ("YES" in step S106), control device 15 advances the program to step S108, and the water quantity sensor 14a increases the predetermined water quantity within time t1. Is not detected (“NO” in step S106), the program proceeds to step S124.

  In step S108, the control device 15 stops the reforming water pump 11b1, and stands by without processing for a predetermined time (for example, 60 seconds). Accordingly, when the second reforming water level adjustment described later is performed, it is possible to suppress that air is mixed in the reforming water pump 11b1 and the water supply pipe 11b.

  Then, in step S110, the control device 15 returns the amount of reforming water, which is the amount of reforming water returned to the water tank 14 by the first reforming water level adjustment (= detection time t2 x delivery of the reforming water pump 11b1 Calculate the flow rate α). That is, the control device 15 can calculate the return amount of the reforming water (return amount calculation unit) based on the detection result of the water amount sensor 14a (the detection of the increase of the predetermined water amount of the water tank 14 described above).

  Thereafter, in step S112, the control device 15 performs second reforming water level adjustment to raise the water surface of the reforming water in the water supply pipe 11b from the first return water level (second reforming water level adjustment control unit) . Specifically, after the first reformed water level adjustment is performed by the first reformed water level adjustment control unit, the control device 15 performs a drive corresponding to the reformed water return amount by the first reformed water level adjustment. The second reforming water level adjustment is performed by commanding to drive the reforming water pump 11b1, which is the reforming water delivery device, only for the command time.

  Furthermore, in step S112, the control device 15 calculates a drive command time from the reformed water return amount calculated by the return amount calculation unit (drive command time calculation unit). Specifically, control device 15 calculates a constant β corresponding to detection time t2 using the map shown in FIG. 4 and calculates a value obtained by adding constant β to detection time t2 as a drive command time (= t2 + β). Do. The map shown in FIG. 4 shows the relationship between the detection time t2 and the constant β (for example, the constant β is represented by a linear function of the detection time t2), and the constant β increases as the detection time t2 increases. Is set as.

  That is, the control device 15 starts the positive rotation of the reforming water pump 11b1, and continues the positive rotation for a drive command time (= t2 + β) at a flow rate of αcc / min. As a result, the reformed water in the water tank 14 is pumped up and delivered to the water supply pipe 11 b and hence to the evaporator 32. At this time, since the drive command time is t 2 + β, it can be set longer by a constant β than the time t 2 when the reformed water is returned to the water tank 14. Therefore, if there is no failure in the water supply pipe 11b or the reforming water pump 11b1, the water level of the reforming water can be set to a position higher than the initial water level in the water supply pipe 11b. Further, since the constant β is set in consideration of the amount by which the initial water level deviates from the reference water level, the second reformed water level adjustment makes the water level of the reformed water higher than the reference water level. be able to.

  Whether or not the water level sensor 11b2 detects that the water level of the reforming water has reached the reference water level ("with water") after the time when the second reforming water level adjustment has been started in step S114 Determine if Further, in step S114, the time taken from when the second reforming water level adjustment is started to when the water level sensor 11b2 detects that the reforming water level has reached the reference water level Detection time) measure t4. That is, when the second reformed water level adjustment control unit performs the second reformed water level adjustment by the second reformed water level adjustment control unit, the control device 15 uses the detection result of the water level sensor 11b2 to form the reformed water in the water supply pipe 11b. The time taken for the water surface to reach from the first return water level to the reference water level is measured as a measurement time (detection time) t4 (measurement unit).

  If water level sensor 11b2 detects the presence of water within the drive command time (= t2 + β) (“YES” in step S114), control device 15 advances the program to step S116 and the water level within drive command time (t2 + β) If the sensor 11b2 does not detect the presence of water ("NO" in step S114), the program proceeds to step S122.

  In step S116, the control device 15 stores the detection time t4 and stops the positive rotation of the reforming water pump 11b1 to stop the reforming water replenishment (pumping up). Thereafter, in step S118, the control device 15 is the water supply pipe 11b and the reformed water delivery device based on the relationship between the drive command time and the detection time (measured time) t4 measured by the measurement unit. It is determined whether the reforming water pump 11b1 is normal. That is, in step S118, the controller 15 controls the water supply pipe 11b and the reformed water delivery apparatus based on the relationship between the drive command time and the detection time t4 measured by the measurement unit. The failure of 11b1 is determined (determination unit).

  Specifically, when the relationship between the drive command time and the detection time t4 is within the normal range shown in FIG. 5 using the map shown in FIG. It is determined that the reforming water pump 11b1, which is a quality water delivery device, is normal. On the other hand, when the relationship between the drive command time and the detection time t4 is out of the normal range shown in FIG. 5, the water supply pipe 11b or the reforming water pump 11b1 which is the reforming water delivery device is abnormal (faulty). Determine that there is.

  The map shown in FIG. 5 can be created by experiment. When the water supply pipe 11b and the reforming water pump 11b1 are normal without any failure, the drive command time is changed to measure the detection time t4, and a normal range is created from the relationship between the drive command time and the detection time t4. be able to. Similarly, when there is a water leak failure in the water supply pipe 11b, the drive command time is changed and the detection time t4 is measured, and the water leak failure in the water supply pipe 11b from the relationship between the drive command time and the detection time t4. A range of water supply pipe water leakage failure (water supply pipe water leakage failure area) can be created. Water supply pipe The water leak failure range is located above the upper limit of the normal range, that is, the normal range. In the case of the water supply pipe water leakage failure, the detection time t4 is longer for the same drive command time as compared with the normal case.

  Furthermore, similarly, when the delivery capacity of the reforming water pump 11b1 is lowered, the drive command time is changed to measure the detection time t4, and from the relationship between the drive command time and the detection time t4, the reformed water is It is possible to create a range of the reforming water pump capability lowering failure (reforming water pump capability lowering failure range) in which the delivery capacity of the pump 11b1 is reduced. The reforming water pump capability reduction failure range is located above the upper limit value of the normal range, that is, the normal range. In the case of the reforming water pump performance lowering failure, the detection time t4 is longer for the same drive command time as compared with the normal case.

  Furthermore, similarly, when the delivery capacity of the reforming water pump 11b1 is excessive, the drive command time is changed to measure the detection time t4, and from the relationship between the drive command time and the detection time t4, the reformed water pump It is possible to create a range of reforming water pump capacity excess failure where the 11b1 delivery capacity is excessive (reforming water pump capacity excess failure range). The reforming water pump capacity excess failure range is located below the normal range, that is, the lower limit value of the normal range. In the case of the reforming water pump capacity excess failure, the detection time t4 is shorter for the same drive command time as compared with the normal case.

  If the relationship between the drive command time and the detection time t4 is within the normal range shown in FIG. 5, the control device 15 determines “YES” in step S118, and changes the water supply pipe 11b and the change in step S120. It is determined that the quality water pump 11b1 is normal (determination unit). Thereafter, the control device 15 once ends the program. On the other hand, when the relationship between the drive command time and the detection time t4 is out of the normal range shown in FIG. 5, the control device 15 determines “NO” in step S118 and advances the program to step S202 and subsequent steps. .

  When the relationship between the drive command time and the detection time t4 is below the normal range, the control device 15 determines "small" in step S202, and the reforming water pump 11b1 (reforming in step S204) It is determined that the delivery capability of the water delivery device is excessive (determination unit). In step S202, when the relationship between the drive command time and the detection time t4 is below the normal range, the control device 15 determines that the relationship between the drive command time and the detection time t4 is the normal range lower limit. If the relationship between the drive command time and the detection time t4 is above the normal range, the relationship between the drive command time and the detection time t4 is the normal range upper limit value. Determined to be greater.

  When the relationship between the drive command time and the detection time t4 is above the normal range, the control device 15 determines "large" in step S202, and the reforming water pump 11b1 (revised in step S206 and subsequent steps). It is judged whether it is a reformed water delivery device delivery lowering failure in which the delivery capacity of the quality water delivery device is decreasing, or a water supply pipe water leak failure in which the water supply pipe 11b is leaking (determination section ).

  Specifically, the control device 15 operates the reforming water pump 11b1, which is the reforming water return device, for a predetermined time (reforming water to the water tank 14 side (removal control of the reforming water)) The water surface of the reformed water in the water supply pipe 11b is lowered from the reference water level to a second return water level lower than the reference water level (step S206). Thereafter, the control device 15 operates the reforming water pump 11b1, which is a reforming water delivery device, for the predetermined time (reforming water is pumped up from the water tank 14 (reforming control of reforming water)) to supply water The water surface of the reformed water in the pipe 11b is raised from the second return water level (step S208). Thereafter, when the water surface of the reforming water is returned to the reference water level (determined as “YES” in step S210), the control device 15 reduces the delivery capacity of the reforming water pump 11b1. It is determined that there is a failure (step S212). In step S210, the control device 15 determines whether the water level sensor 11b2 detects that the water level of the reformed water has reached the reference water level ("water present") as in the process of step S114 described above. judge.

  In the case where the reforming control of reforming water and the replenishment control of reforming water are carried out for the same time and for the same time, if there is a water leak in the water supply pipe 11b, the height of the water surface is different before and after both controls. However, when there is no water leak in the water supply pipe 11b, the height of the water surface becomes the same before and after both controls. By utilizing this principle, it is possible to determine whether it is a reforming water delivery device delivery lowering failure or a water supply pipe water leakage failure.

  Furthermore, the control device 15 operates the reforming water pump 11b1, which is the reforming water return device, for a predetermined time (reform water to the water tank 14 side), and the reformed water in the water supply pipe 11b is The water surface is lowered from the reference water level to the second return water level, which is a position lower than the reference water level (step S206). Thereafter, the control device 15 operates the reforming water pump 11b1, which is a reforming water delivery device, for the predetermined time (to draw up the reforming water from the water tank 14), and the reforming water in the water supply pipe 11b is The water surface is raised from the second return water level (step S208). Thereafter, when the water surface of the reformed water has not returned to the reference water level (judged as “NO” in step S210), the control device 15 determines that the water supply pipe 11b has a leak failure (step S214). ).

  The description returns to step S122. If the water level sensor 11b2 does not detect the presence of water within the drive command time (t2 + β), the control device 15 advances the program to step S122. Normally, if the second reformed water level adjustment is performed, the reformed water level should reach the detection section of the water level sensor 11b2, but the water level sensor 11b2 is within the drive command time (t2 + β) If not detected, it may be considered that the water level sensor 11b2 has a failure, the water supply pipe 11b has a water leakage failure, or the reforming water pump 11b1 has a performance reduction failure.

  Therefore, when the water level sensor 11b2 does not detect the presence of water within the drive command time (t2 + β), the control device 15 determines “NO” in step S114, and in step S122 the failure of the water level sensor 11b2, the water supply pipe It is determined that there is a water leak failure of 11b or a power reduction failure of the reforming water pump 11b1.

  In step S122, the temperature of the evaporating unit 32 after the measurement by the measuring unit detected by the temperature sensor 32a is lower than the temperature of the evaporating unit 32 before the measurement by the measuring unit detected by the temperature sensor 32a. If it does, it can be determined that the water level sensor 11b2 has failed. This determination utilizes the principle that the temperature of the evaporating unit 32 decreases when the reforming water exceeds the water level sensor 11 b 2 and is fed to the evaporating unit 32 by adjusting the second reforming water level.

  Furthermore, the description returns to the process of step S106. If the water amount sensor 14a does not detect an increase in the predetermined water amount within the time t1, the control device 15 determines "NO" in step S106, and advances the program to step S124. In step S124, the control device 15 stops the reforming water pump 11b1 in the same manner as step S108 described above, and stands by without processing for a predetermined time (for example, 60 seconds).

  Thereafter, in step S126, the control device 15 performs second reforming water level adjustment to raise the water surface of the reforming water in the water supply pipe 11b from the first return water level as in step S112 described above (second Reformed water level adjustment control unit). Specifically, after the first reformed water level adjustment is performed by the first reformed water level adjustment control unit, the control device 15 performs a drive corresponding to the reformed water return amount by the first reformed water level adjustment. The second reforming water level adjustment is performed by commanding to drive the reforming water pump 11b1, which is the reforming water delivery device, only for the command time.

  Furthermore, in step S126, the control device 15 sets a drive command time (drive command time setting unit). For example, the control device 15 sets the drive command time to time t3. The time t3 is preferably a value obtained by adding a constant γ to a value obtained by dividing the volume from the water level sensor 11b2 of the water supply pipe 11b to the connection end of the water tank 14 by the above-mentioned delivery flow rate α.

  That is, the control device 15 starts the positive rotation of the reforming water pump 11b1 and continues the positive rotation for the drive command time (= t3) at a flow rate of αcc / min. As a result, the reformed water in the water tank 14 is pumped up and delivered to the water supply pipe 11 b and hence to the evaporation unit 32. At this time, since the drive command time is t3, if there is no failure in the water supply pipe 11b or the reforming water pump 11b1, the water level of the reforming water in the water supply pipe 11b should be higher than the reference water level. it can.

  The control device 15 indicates that the water level of the reforming water has reached the reference water level (“with water”) after the time when the second reforming water level adjustment has been started in step S128 as in the above-described step S114. It is determined whether the water level sensor 11b2 has detected it. Further, in step S128, the time taken from when the second reforming water level adjustment is started to when the water level sensor 11b2 detects that the reforming water level has reached the reference water level Detection time) measure t4. That is, when the second reformed water level adjustment control unit performs the second reformed water level adjustment by the second reformed water level adjustment control unit, the control device 15 uses the detection result of the water level sensor 11b2 to form the reformed water in the water supply pipe 11b. The time taken for the water surface to reach from the first return water level to the reference water level is measured as a measurement time (detection time) t4 (measurement unit).

  If water level sensor 11b2 detects presence of water within the drive command time (= t3) ("YES" in step S128), control device 15 advances the program to step S130, and the water level is within drive command time (t3). If the sensor 11b2 does not detect the presence of water ("NO" in step S128), the program proceeds to step S122.

  In step S130, the control device 15 stores the detection time t4 and stops the positive rotation of the reforming water pump 11b1 and stops the reforming water supply (suction) similarly to step S116 described above. After that, in step S132, the controller 15 performs the water based on the relationship between the drive command time (t3) and the detection time (measured time) t4 measured by the measurement unit, as in step S118 described above. It is determined whether or not the supply pipe 11b and the reforming water pump 11b1, which is a reforming water delivery device, are normal. As a result, in step S132, the controller 15 controls the water supply pipe 11b and the reformed water delivery device based on the relationship between the drive command time and the detection time t4 measured by the measurement unit. The failure of 11b1 is determined (determination unit).

  If the relationship between the drive command time (t3) and the detection time t4 is within the normal range shown in FIG. 5, the control device 15 determines “YES” in step S132, and the water supply pipe in step S120. It is determined that the 11b and the reforming water pump 11b1 are normal (determination unit). Thereafter, the control device 15 once ends the program. On the other hand, when the relationship between the drive command time and the detection time t4 is out of the normal range shown in FIG. 5, the control device 15 determines “NO” in step S132 and advances the program to step S202 and subsequent steps. .

  As apparent from the above description, the fuel cell system 1 of the present embodiment generates a fuel from the fuel cell 34 that generates electric power by the fuel and the oxidant gas, the raw material for reforming, and the reforming water, 34, a combustion unit 36 for introducing combustible gas including unused fuel from the fuel cell 34 and combusting with oxidant gas to lead out combustion exhaust gas; combustion exhaust gas and heat medium The heat exchanger 12 exchanges heat and condenses the water vapor contained in the combustion exhaust gas to generate condensed water, and the condensed water supplied from the heat exchanger 12 is stored as reforming water as well. A water tank 14 for supplying to the reforming unit 33, a water supply pipe 11b for supplying reformed water from the water tank 14 to the reforming unit 33, and a water supply pipe 11b are provided. Reformed water delivery device (reformed water pump to be delivered to the reforming unit 33 11b1), a reforming water return device (reforming water pump 11b1) provided in the water supply pipe 11b and returning the reformed water in the water supply pipe 11b back to the water tank 14, and a water supply pipe 11b The fuel cell system is provided with a water level sensor 11b2 for detecting whether the water surface of the reformed water in the supply pipe 11b is at a reference water level, and a control device 15 for performing control to generate the fuel cell 34. . The control device 15 operates the reforming water return device (reforming water pump 11b1) to move the water surface of the reforming water in the water supply pipe 11b from the initial water level to the first return water level which is a position lower than the initial water level. After the first reforming water level adjustment control unit (step S104) performing the first reforming water level adjustment to be lowered and the first reforming water level adjustment by the first reforming water level adjustment control unit, the first The reforming water delivery device (reforming water pump 11b1) is commanded to be driven for a drive command time corresponding to the amount of return of the reforming water by the reforming water level adjustment, and the reforming water in the water supply pipe 11b is The second reformed water level adjustment control unit (step S112, 126) for adjusting the second reformed water level to raise the water surface from the first return water level (steps S112, 126), and the second reformed water by the second reformed water level adjustment control unit When adjusting the water level, using the detection result of the water level sensor 11b2, A measurement unit (steps S114, 128) that measures the time taken for the water surface of the reformed water in feed pipe 11b to reach from the first return water level to the reference water level, a drive command time, a measurement unit And a determination unit (steps S118, 132, and 202-214) that determines a failure of the water supply pipe 11b and the reformed water delivery apparatus based on the relationship with the actual measurement time measured by the above.

  According to this, the control device 15 operates the reforming water return device (reforming water pump 11b1) to lower the water surface of the reforming water in the water supply pipe 11b to the first return water level (first Adjust the reforming water level), and then drive the reforming water delivery device (reforming water pump 11b1) for the drive command time corresponding to the return amount of the reforming water by the first reforming water level adjustment, and the water supply pipe The water surface of the reforming water in 11b is raised from the first return water level (second reforming water level adjustment). At this time, the control device 15 uses the detection result of the water level sensor 11b2 to measure the time taken for the water surface of the reformed water in the water supply pipe 11b to reach from the first return water level to the reference water level as the measurement time. Do (Measuring section). Then, the control device 15 determines a failure of the water supply pipe 11b and the reforming water delivery device (reforming water pump 11b1) based on the relationship between the drive command time and the actual measurement time measured by the measuring unit ( Judgment part). As a result, in the fuel cell system 1, it is possible to specify an abnormal part of the water supply system provided from the water tank 14 to the reforming unit 33, and consequently, maintainability can be improved.

The fuel cell system 1 further includes a water amount sensor 14a provided in the water tank 14 for detecting the water amount of the reforming water in the water tank 14, and the control device 15 detects the water amount based on the detection result of the water amount sensor 14a. A return amount calculation unit (step S110) that calculates a return amount of reformed water and a drive command time calculation unit (step S112) that calculates a drive command time from the return amount of reformed water calculated by the return amount calculation unit And further.
According to this, the drive command time can be appropriately calculated, and consequently, the reformed water can be appropriately supplied from the water tank 14 to the water supply pipe 11b without waste.

In the determination unit (control device 15), the relationship between the drive command time and the actual measurement time measured by the measurement unit is normal for the water supply pipe 11b and the reforming water delivery device (reforming water pump 11b1). If it is below the normal range, it is determined that there is a delivery excess failure in which the delivery capacity of the reforming water delivery apparatus (reforming water pump 11 b 1) is excessive (step S 204).
According to this, in the fuel cell system 1, it is possible to specify an abnormal part of the water supply system provided from the water tank 14 to the reforming unit 33.

In the determination unit (control device 15), the relationship between the drive command time and the actual measurement time measured by the measurement unit is normal for the water supply pipe 11b and the reforming water delivery device (reforming water pump 11b1). It is above the normal range, and the reforming water return device (reforming water pump 11b1) is operated for a predetermined time to position the water surface of the reforming water in the water supply pipe 11b lower than the reference water level from the reference water level. Then, the water level of the reformed water in the water supply pipe 11b is reduced from the second return water level by operating the reformed water delivery device (reforming water pump 11b1) for a predetermined time. If the water surface of the reforming water returns to the reference water level after raising it, it is determined that it is a delivery reduction failure in which the delivery capacity of the reforming water delivery apparatus (reforming water pump 11b1) is reduced ( Step S212).
According to this, in the fuel cell system 1, it is possible to specify an abnormal part of the water supply system provided from the water tank 14 to the reforming unit 33.

In the determination unit (control device 15), the relationship between the drive command time and the actual measurement time measured by the measurement unit is normal for the water supply pipe 11b and the reforming water delivery device (reforming water pump 11b1). It is above the normal range, and the reforming water return device (reforming water pump 11b1) is operated for a predetermined time to position the water surface of the reforming water in the water supply pipe 11b lower than the reference water level from the reference water level. Then, the water level of the reformed water in the water supply pipe 11b is reduced from the second return water level by operating the reformed water delivery device (reforming water pump 11b1) for a predetermined time. If the water surface of the reformed water has not returned to the reference water level after the rise, it is determined that the water supply pipe 11b has a leak failure (step S214).
According to this, in the fuel cell system 1, it is possible to specify an abnormal part of the water supply system provided from the water tank 14 to the reforming unit 33.

In addition, the fuel cell system 1 further includes a temperature sensor 32a provided in the evaporation unit 32 for detecting the temperature of the evaporation unit 32, and the measurement time can not be measured by the measurement unit (steps S114 and 128). When the temperature of the evaporating unit 32 after measurement by the measuring unit detected by the sensor 32a is lower than the temperature of the evaporating unit 32 before measurement by the measuring unit detected by the temperature sensor 32a, the temperature of the water level sensor 11b2 It is determined that there is a failure (step S122).
According to this, in the fuel cell system 1, it is possible to specify an abnormal part of the water supply system provided from the water tank 14 to the reforming unit 33.

  In the embodiment described above, the reforming water pump 11b1 capable of forward and reverse rotation is adopted and the reforming water pump 11b1 is used both as the reforming water delivery device and the reforming water return device. The device and the reforming water return device may be configured by separate reforming water pumps.

  Further, in the above-described embodiment, the reforming water pump 11b1 capable of forward and reverse rotation is adopted, and the reforming water pump 11b1 is used both as the reforming water delivery device and the reforming water return device. The device may be configured by a positive rotation reforming water pump and the reforming water return device may be configured by a solenoid valve.

  As shown in FIG. 6, instead of the reforming water pump 11b1 shown in FIG. 1, a reforming water pump 11b3 is provided in the water supply pipe 11b, and a bypass pipe 11b5 bypassing the reforming water pump 11b3 is provided with a solenoid valve 11b4. It is done. The reforming water pump 11b3 may be a pump that only rotates forward, or may be a pump that rotates forward and reverse. The solenoid valve 11b4 opens and closes the bypass pipe 11b5 in accordance with an instruction from the control device 15.

The control of the fuel cell system according to this modification will be described in terms of differences from the embodiment described above. As shown in the flowchart of FIG. 7, the control device 15 executes the process of step S302 instead of the process of step S104 of FIG. 2. In step S302, the controller 15 opens the solenoid valve 11b4 for time t1 and then closes it. Thereby, the reformed water in the water supply pipe 11b is drained by its own weight, thereby lowering the water surface of the reformed water in the water supply pipe 11b from the initial water level to the first return water level which is a position lower than the initial water level. The first reforming water level adjustment is performed (first reforming water level adjustment control unit). As a result, the reformed water in the water supply pipe 11b downstream of the reformed water pump 11b3 is returned to the water tank 14.
The time t1 is preferably set to a time in which the entire amount (equal to the piping volume) of the reforming water from the evaporation part 32 of the water supply pipe 11b to the reforming water pump 11b3 can be delivered.

  Furthermore, as shown in the flowchart of FIG. 8, the control device 15 executes the process of step S304 instead of the process of step S206 of FIG. 2. In step S304, the control device 15 opens the solenoid valve 11b4, which is a reforming water return device, for a time t5 (reforming water to the water tank 14 side (reforming water return control)), and then closes it. . Thereby, the control device 15 lowers the water surface of the reformed water in the water supply pipe 11b from the reference water level to the second return water level which is a position lower than the reference water level.

  Furthermore, the control device 15 executes the process of step S306 in place of the process of step S208 of FIG. In step S306, the control device 15 operates the reforming water pump 11b3, which is a reforming water delivery device, for a time t6 (reforming water from the water tank 14 (reforming control of reforming water)), The water surface of the reforming water in the supply pipe 11b is raised from the second return water level. The time t5 and the time t6 have a relationship shown in FIG. Further, the time t5 × the amount of dropped water when the solenoid valve 11b4 is open is in a relationship equal to the time t6 × the amount delivered by the reforming water pump 11b3. In FIG. 9, a solid line shows the case where the reformed water return amount is α mentioned above, a dotted line shows the case where the reformed water return amount is larger than the above mentioned α, and the reformed water return amount mentioned above The case where it is smaller than α is indicated by an alternate long and short dash line.

Reference Signs List 1 fuel cell system 11b water supply pipe 11b1 reforming water pump (reforming water delivery device, reforming water return device) 11b2 water level sensor 12 heat exchanger 14 water tank 14a Water amount sensor, 15 ... control device (first reforming water level adjustment control unit (step S104), second reforming water level adjustment control unit (steps S112, 126), measuring unit (steps S114, 128), determination unit (step S114, 128) Steps S118, 132, 202-214), return amount calculation unit (step S110), drive command time calculation unit (step S112), 32: evaporation unit, 33: reforming unit, 34: fuel cell, 36: combustion unit .

Claims (6)

A fuel cell that generates electricity from fuel and oxidant gas;
A reforming unit that generates the fuel from the reforming raw material and the reforming water and supplies the fuel to the fuel cell;
A combustion unit for introducing a combustible gas containing the unused fuel from the fuel cell and burning it with an oxidant gas to lead out a flue gas;
A heat exchanger for performing heat exchange between the flue gas and a heat medium to condense water vapor contained in the flue gas to generate condensed water;
A water tank that stores condensed water supplied from the heat exchanger as the reforming water and supplies the condensed water to the reforming unit;
A water supply pipe for supplying the reforming water from the water tank to the reforming unit;
A reformed water delivery device provided in the water supply pipe for delivering the reformed water in the water tank to the reforming unit;
A reforming water return device provided in the water supply pipe for returning the reformed water in the water supply pipe to the water tank;
A water level sensor provided on the water supply pipe for detecting whether the water surface of the reformed water in the water supply pipe is at a reference water level;
A control device that performs control to generate the fuel cell;
A fuel cell system comprising:
The controller is
The first reforming water level adjustment is performed by operating the reforming water return device to lower the water surface of the reforming water in the water supply pipe from an initial water level to a first return water level lower than the initial water level. The first reforming water level adjustment control unit to
After performing the first reforming water level adjustment by the first reforming water level adjustment control unit, the reforming is performed for a drive command time corresponding to the return amount of the reforming water by the first reforming water level adjustment. A second reforming water level adjustment control unit that performs a second reforming water level adjustment to raise the water surface of the reforming water in the water supply pipe from the first return water level by commanding to drive the water delivery device When,
When the second reforming water level adjustment control unit performs the second reforming water level adjustment, the water surface of the reforming water in the water supply pipe is the first return using the detection result of the water level sensor. A measurement unit that measures a time taken to reach the reference water level from the water level as a measurement time;
A fuel cell system comprising: a determination unit that determines a failure of the water supply pipe and the reformed water delivery device based on a relationship between the drive command time and an actual measurement time measured by the measurement unit. The fuel cell system is
The water tank further includes a water amount sensor provided in the water tank for detecting the water amount of the reformed water in the water tank,
The controller is
A return amount calculation unit that calculates a return amount of the reformed water based on the detection result of the water amount sensor;
The fuel cell system according to claim 1, further comprising: a drive command time calculation unit that calculates the drive command time from the return amount of the reforming water calculated by the return amount calculation unit.   The determination unit determines that the relationship between the drive command time and the actual measurement time measured by the measurement unit is below the normal range in which the water supply pipe and the reformed water delivery device are normal. The fuel cell system according to claim 1 or 2, wherein it is determined that the delivery capacity of the reformed water delivery apparatus is excessive, which is a delivery excess failure. The determination unit has a relationship between the drive command time and an actual measurement time measured by the measurement unit above a normal range in which the water supply pipe and the reformed water delivery apparatus are normal.
And,
The reformed water return device is operated for a predetermined time to lower the water surface of the reformed water in the water supply pipe to a second return water level which is a position lower than the reference water level from the reference water level, and thereafter, After the reformed water delivery apparatus is operated for the predetermined time to raise the water surface of the reformed water in the water supply pipe from the second return water level, the water surface of the reformed water returns to the reference water level 3. The fuel cell system according to claim 1, wherein it is determined that the reduced delivery failure of the reformed water delivery apparatus is present. The determination unit has a relationship between the drive command time and an actual measurement time measured by the measurement unit above a normal range in which the water supply pipe and the reformed water delivery apparatus are normal.
And,
The reformed water return device is operated for a predetermined time to lower the water surface of the reformed water in the water supply pipe to a second return water level which is a position lower than the reference water level from the reference water level, and thereafter, After the reformed water delivery apparatus is operated for the predetermined time to raise the water surface of the reformed water in the water supply pipe from the second return water level, the water surface of the reformed water returns to the reference water level The fuel cell system according to claim 1 or 2, wherein it is determined that the water supply pipe has a leak failure if not. The fuel cell system further includes a temperature sensor provided in an evaporation unit that evaporates the reforming water and supplies the reformed water to the reforming unit, and detects a temperature of the evaporation unit.
In the case where the measurement unit can not measure the actual measurement time, the temperature of the evaporation unit after the measurement by the measurement unit detected by the temperature sensor is measured by the measurement unit detected by the temperature sensor The fuel cell system according to any one of claims 1 to 5, wherein when the temperature is lower than the temperature of the previous evaporation unit, it is determined that the water level sensor is broken.

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