JP2008177129A - Drainage equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drainage equipment in which excessive exhaustion of gas is prevented and freezing of a switching means of a valve or the like is prevented. <P>SOLUTION: While a fuel cell system is stopped, after an internal pressure of a water storing means is reduced by a pressure adjusting means with an external pressure of an open end side of a drainage passage as a target value, a switching means is controlled to be in an open condition for a freezing prevention treatment. The switching means in a condition of the freezing prevention treatment is positioned higher than a liquid surface of generated water in the drainage passage. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drainage device, and more particularly, a device for draining generated water accompanying power generation out of the system in a fuel cell system including a fuel cell that generates electric power by electrochemically reacting fuel gas and oxidant gas About.

For example, Patent Document 1 discloses a fuel cell system in which a drainage device having a water storage function is provided in a fuel gas discharge channel, and the generated water accompanying the power generation of the fuel cell is discharged to the outside by the drainage device. The drainage device in Patent Document 1 includes a liquid water drain pipe having a gas inlet and a gas discharge valve at a position higher than the maximum water level of the stored water and a suction port below the maximum water level of the stored water. It is connected as an ejector structure. Therefore, by opening the discharge valve, the jet pump effect is generated by the momentum of the exhaust gas flowing through the gas discharge pipe, and the stored water is sucked into the liquid water drain pipe to discharge the stored water to the outside. Can do. Also, in this drainage device, since the exhaust gas passes through the discharge valve, the water remaining in the discharge valve is blown off by the exhaust gas, and this causes the discharge valve to freeze as the outside air temperature decreases when the system stops Is suppressed.
JP 2006-32134 A

  However, according to the technique disclosed in Patent Document 1, when the water of the discharge valve is blown away, it is necessary to actively flow the fuel gas discharged from the fuel cell in order to obtain the jet pump effect. Therefore, according to this method, there is a disadvantage that a large amount of fuel gas is discharged to the outside.

  This invention is made | formed in view of this situation, The objective is to suppress freezing of opening-and-closing means, such as a valve, suppressing the discharge | emission of excess gas.

  In order to solve such a problem, the present invention provides a drainage device that drains water in a fuel cell system including a fuel cell that generates electric power by electrochemically reacting a fuel gas and an oxidant gas. This drainage device has a water storage means, a drainage channel, an opening / closing means, a pressure adjusting means, and a control means. Here, the water storage means stores the generated water accompanying the power generation of the fuel cell. The drainage channel has an upward shape in which a part of the channel extends upward, and after the generated water inside the water storage means is guided upward from the liquid level of this generated water, Drain from the open end. The opening / closing means is provided in the drainage channel and opens and closes the channel. The pressure adjusting means adjusts the internal pressure of the water storage means. The control means controls the opening / closing means and the pressure adjusting means. In this case, when the system in the fuel cell system is stopped, the control means uses the external pressure on the open end side of the drainage flow path as a target value, and the internal pressure of the water storage means is reduced by the pressure adjusting means, and then the opening and closing means Freezing suppression processing is performed to control the to open state. Further, the opening / closing means is disposed above the level of the produced water in the drainage flow channel in the state where the freeze suppression process is performed.

  As freezing suppression treatment, the internal pressure of the water storage means is reduced to the external pressure on the open end side of the drainage flow path, and then the liquid level in the drainage flow path is lowered by controlling the opening / closing means to the open state. Therefore, it is possible to suppress a state in which the opening / closing means is immersed in the generated water during the period when the system is stopped. In addition, in order to remove the water in the opening / closing means, there is no need to actively flow the fuel gas to discharge the generated water to the outside, so that the opening / closing means can be prevented from freezing while suppressing the discharge of excess gas. Can do.

(First embodiment)
FIG. 1 is a block diagram showing a configuration of a fuel cell system according to an embodiment of the present invention. This fuel cell system is mounted on a vehicle as a power source of an electric motor (not shown) that drives the vehicle, for example.

  The fuel cell system includes a fuel cell stack 1 in which a fuel cell structure in which a solid polymer electrolyte membrane is sandwiched between an oxidant electrode and a fuel electrode is sandwiched between separators, and a plurality of these are stacked. . This fuel cell stack 1 is supplied with fuel gas to each fuel electrode via a fuel gas passage (not shown) formed inside the stack, and an oxidant gas passage formed inside the stack. When an oxidant gas is supplied to each oxidant electrode (not shown), these gases are electrochemically reacted to generate electric power. In this embodiment, hydrogen is used as the fuel gas and air is used as the oxidant gas.

  The fuel cell system including the fuel cell stack 1 includes a hydrogen system 10 for supplying hydrogen to the fuel cell stack 1 and an air system 20 for supplying air to the fuel cell stack 1.

  In the hydrogen system 10, hydrogen as a fuel gas is supplied to the fuel cell stack 1 from a fuel supply means (for example, a fuel tank 11 that is a high-pressure hydrogen cylinder) via a hydrogen supply flow path L10. Specifically, a fuel tank main valve (not shown) is provided downstream of the fuel tank 11, and when the fuel tank main valve is opened, the hydrogen in the fuel tank 11 is transferred to the hydrogen supply flow path L10. To leak. The high-pressure hydrogen from the fuel tank 11 is mechanically reduced to a predetermined pressure by a pressure reducing valve (not shown) provided downstream of the fuel tank main valve. The depressurized hydrogen is further depressurized by a hydrogen pressure regulating valve 12 provided downstream of the depressurizing valve, and then supplied to the fuel cell stack 1. The opening of the hydrogen pressure regulating valve 12 is controlled by the control unit 30 described later so that the hydrogen pressure supplied to the fuel cell stack 1 becomes a desired value.

  Exhaust gas (gas containing unused hydrogen) from the fuel electrode of the fuel cell stack 1 is discharged to the hydrogen circulation passage L11. The other end of the hydrogen circulation flow path L11 is connected to the hydrogen supply flow path L10 on the downstream side of the hydrogen pressure regulating valve 12, and the hydrogen circulation flow path L11 includes, for example, a hydrogen circulation such as a circulation pump 13. Means are provided. By this hydrogen circulation means, the exhaust gas from the fuel cell stack 1 is circulated to the hydrogen supply side in the fuel cell stack 1. Such a circulation system can improve the fuel efficiency of hydrogen. The driving amount of the circulation pump 13, that is, the rotational speed thereof is controlled by the control unit 30 so that the flow rate of hydrogen supplied to the fuel cell stack 1 becomes a desired value.

  By the way, when air is used as the oxidant gas, nitrogen in the air permeates from the oxidant electrode to the fuel electrode, so that the nitrogen concentration of the gas in the circulation system increases and the hydrogen partial pressure tends to decrease. Therefore, the hydrogen circulation flow path L11 is connected to a hydrogen discharge flow path L12 for discharging the gas in the hydrogen system. A purge valve 14 is provided in the hydrogen discharge flow path L12, and exhaust gas (gas containing nitrogen, unused hydrogen, etc.) flowing through the hydrogen circulation flow path L11 is switched by switching the open / close state of the purge valve 14. It is discharged outside. The open / close state of the purge valve 14 is controlled by the control unit 30 in accordance with the operating state of the fuel cell stack 1. For example, the purge valve 14 is basically controlled to be in a closed state, and the nitrogen concentration in the fuel electrode is estimated, or can be switched from the closed state to the open state as necessary at predetermined intervals. is there. Thereby, nitrogen is purged from the hydrogen system 10 together with unreacted hydrogen, and a decrease in hydrogen partial pressure can be suppressed. This hydrogen discharge flow path L12 is connected to an air discharge flow path L21, which will be described later, and the exhaust gas from the purge valve 14 is diluted with the air discharged from the fuel cell stack 1 and then released to the outside.

  Further, a drainage device 15 that discharges generated water accompanying the power generation of the fuel cell stack 1 is provided in the hydrogen circulation flow path L11 on the upstream side of the circulation pump 13. FIG. 2 is a configuration diagram schematically illustrating the drainage device 15 according to the first embodiment. The drainage device 15 is mainly composed of a separator tank 16 and an opening / closing valve 17.

  The separator tank 16 has a substantially cylindrical tank with a space inside as a main body, and a partition plate 16a having an opening at the center is inscribed in the middle part of the main body. The partition plate 16a divides the internal space of the main body into upper and lower parts, and the upper space functions as a gas-liquid separation unit 16b and the lower space functions as a water storage unit 16c. A mixed fluid in which the circulating gas mainly composed of hydrogen and the generated water are mixed is introduced into the gas-liquid separator 16b which is an upper space. The introduced mixed fluid swirls inside the gas-liquid separator 16b along the wall surface, and is thereby separated into a gas component (circulation gas) and a liquid component (product water). The separated circulating gas flows out to the downstream side of the hydrogen circulation channel L11 through an opening formed in the upper part of the main body. On the other hand, the separated generated water moves downward from the main body due to its own weight and is stored in the water storage section 16c.

  A discharge port 16d, which is an opening for discharging generated water stored in the water storage section 16c, is formed in the lower part of the main body, and an upstream drainage flow path L13 is connected to the discharge port 16d. This upstream drainage flow path L13 is connected to the downstream drainage flow path L14 via the open / close valve 17, and the generated water in the water storage section 16c is circulated on the condition that the open / close valve 17 is open. Due to the internal pressure of the system, that is, the separator tank 16, it is discharged to the outside through the upstream drainage flow path L13 and the downstream drainage flow path L14. In the present embodiment, the upstream drainage flow path L13 bends and extends in the horizontal direction after extending vertically downward, and then bends and extends vertically upward. In addition, when the upstream drainage flow path L13 extends above the level of the generated water in the separator tank 16, that is, in this embodiment, to a position corresponding to the gas-liquid separation portion 16b, it is then bent to the horizontal direction. And is connected to the downstream drainage flow path L14 via an open / close valve 17 provided at the open end thereof. In the present embodiment, the downstream drainage flow path L14 extends in the horizontal direction, and an end portion thereof is open to the outside. In the present embodiment, the opening / closing valve 17 is disposed at a height position corresponding to the gas-liquid separation unit 16 b, and the opening / closing state is controlled by the control unit 30. Further, the opening / closing valve 17 and the drainage channels L13 and L14 are subjected to water repellent treatment. In the present specification, the terms upstream and downstream are used with reference to the flow of generated water discharged from the separator tank 16 to the outside of the system.

  Referring again to FIG. 1, in the air system 20, the air, which is an oxidant gas, is pressurized and supplied to the fuel cell stack 1 via the air supply flow path L <b> 20 when the atmosphere is taken in by the compressor 21. Is done. The air supply passage L20 is provided with a humidifier 22 at the rear stage of the compressor 21, and the air supplied to the fuel cell stack 1 is humidified to such an extent that the power generation efficiency is not lowered. Exhaust gas (air in which oxygen has been consumed) from the fuel cell stack 1 is discharged to the outside (atmosphere) via the air discharge flow path L21. An air pressure adjusting valve 23 is provided in the air discharge flow path L21. The air pressure regulating valve 23 is controlled by the control unit 30 so that the air pressure and the air flow supplied to the fuel cell stack 1 have desired values together with the drive amount (rotation speed) of the compressor 21. Is done.

  In such a fuel cell system, an output extraction device (not shown) is connected to the fuel cell stack 1. The output extraction device is controlled by the control unit 30 and extracts a necessary output (for example, electric power) from the fuel cell stack 1. The electric power extracted by the output extraction device is supplied to the drive motor via a motor control unit (not shown) that controls the drive motor (not shown) of the vehicle. In addition, a secondary battery (not shown) that can be charged and discharged in parallel with the motor control unit is connected to the output extraction device. The secondary battery is charged with the electric power extracted by the output extraction device and the regenerative electric power from the drive motor. The electric power stored in the secondary battery is supplied to the drive motor via the motor control unit.

  As the control unit (control means) 30, for example, a microcomputer mainly composed of a CPU, a ROM, a RAM, and an input / output interface can be used. The control unit 30 controls the operating state of the fuel cell stack 1 by controlling each part of the system. In accordance with a control program stored in the ROM, the control unit 30 calculates, for example, the opening degree of the hydrogen pressure regulating valve 12, the opening degree calculation of the air pressure regulating valve 23, the rotational speed calculation of the circulation pump 13, and the rotational speed of the compressor 21. Perform the operation. And the control part 30 outputs the controlled variable (control signal) calculated by this calculation with respect to various actuators, the opening degree of the hydrogen pressure regulating valve 12, the opening degree of the air pressure regulating valve 23, the circulation pump 13 The rotational speed and the rotational speed of the compressor 21 are controlled.

  Further, in relation to the present embodiment, the control unit 30 also has a function of controlling the drainage device 15, and the generated water stored in the separator tank 16 is controlled by controlling the open / close valve 17 of the drainage device 15. I do. During normal operation of the fuel cell system, the control unit 30 appropriately controls the open / close state of the open / close valve 17 to drain generated water. Moreover, the control part 30 performs the freezing suppression process for suppressing that the opening-and-closing valve 17 freezes during a system stop period at the time of a system stop of a fuel cell system.

  Hereinafter, the freeze suppression process executed by the control unit 30 in the fuel cell system having such a configuration will be described. FIG. 3 is a flowchart showing the procedure of the freeze suppression process according to the first embodiment of the present invention. The process shown in this flowchart is invoked when the fuel cell system is stopped and executed by the control unit 30. Here, the determination of the system stop by the control unit 30 is made when the ignition switch is turned off by the user or when the vehicle is in a no-load state for a predetermined time.

  First, in step 10 (S10), atmospheric pressure control is performed. While the fuel cell system is in operation, since hydrogen is supplied to the fuel cell stack 1, the hydrogen circulation passage L11 including the internal space of the separator tank 16 is in a positive pressure state. In this atmospheric pressure control, the pressure state in the separator tank 16 is reduced to an external pressure (in the present embodiment, atmospheric pressure) on the open end side of the drainage channels L13 and L14. As described above, the internal space of the separator tank 16 constitutes a part of the hydrogen circulation passage L11, and the hydrogen system 10 including the hydrogen circulation passage L11 is a closed system. In the present embodiment, the internal pressure of the separator tank 16 is increased by controlling the purge valve 14 to be open while the supply of hydrogen from the fuel tank 11 is stopped and reducing the hydrogen circulation flow path L11 to atmospheric pressure. Depressurize to atmospheric pressure.

  In step 11 (S11), after controlling the open / close valve 17 to the open state, this routine is finished.

  As described above, in this embodiment, the drainage device for draining water in the fuel cell system including the fuel cell that generates electric power by electrochemically reacting the fuel gas and the oxidant gas includes the water storage means, the drainage flow, and the like. It has a path, opening / closing means, pressure adjusting means, and control means. Here, the water storage means has a function of storing the generated water accompanying the power generation of the fuel cell, and the separator tank 16 corresponds to this in the present embodiment. The drainage channel has an upward shape in which a part of the channel extends upward. After the generated water in the separator tank 16 is guided upward from the liquid level of the generated water, the drainage channel The drainage flow path L13 corresponds to this function in the present embodiment. The opening / closing means is provided in the drainage flow path L13 and has a function of opening and closing the flow path. In the present embodiment, the opening / closing valve 17 corresponds to this. The pressure adjusting means has a function of adjusting the internal pressure of the separator tank 16, and the purge valve 14 corresponds to this in the present embodiment. The control means has a function of controlling the on-off valve 17 and the purge valve 14, and the control unit 30 corresponds to this in the present embodiment.

  In this case, when the system in the fuel cell system is stopped, the control unit 30 reduces the internal pressure of the separator tank 16 by the purge valve 14 with the external pressure on the open end side of the drainage channel L13 as a target value, Freezing suppression processing for controlling the open / close valve 17 to the open state is performed. Here, the open / close valve 17 is disposed above the level of the generated water in the drainage flow channel in a state where the freeze suppression process is performed.

  FIG. 4 is an explanatory diagram showing a movement state of the generated water by the freezing suppression process. While the fuel cell system is in operation, hydrogen is supplied to the fuel cell stack 1, so that the hydrogen circulation flow path L 11 including the internal space of the separator tank 16 has a positive pressure at the start of the freezing suppression process accompanying the stop of the system. It is in a state. Further, since the open / close valve 17 is in a closed state, the generated water has a predetermined water level A in the separator tank 16 in a state where the entire upstream drainage flow path L13 is filled.

  When the freeze prevention process is performed, the upstream drainage flow path L13 is opened to the atmosphere via the downstream drainage flow path L14, and as a result, acts on the liquid level in the separator tank 16 and the liquid level in the upstream drainage flow path L13. The pressures to be applied correspond to each other. Here, the opening / closing valve 17 is disposed above the liquid level A in the separator tank 16. Therefore, the generated water in the upstream drainage flow path L13 moves to the separator tank 16 side by its own weight. Thereby, in the upstream drainage flow path L13, the liquid level is lowered below the opening / closing valve 17, and in the separator tank 16, the liquid level is increased from the liquid level A by the amount of the generated water. Then, the liquid level (liquid level B) in the separator tank 16 and the liquid level (liquid level C) in the upstream drainage flow path L13 are in equilibrium with each other between the stages having the same horizontal plane.

  As described above, according to the present embodiment, as the antifreezing process, the internal pressure of the separator tank 16 is reduced to the atmospheric pressure, and then the open / close valve 17 is controlled to be opened, whereby the liquid in the upstream drainage channel L13 is controlled. Since the surface is lowered, it is possible to suppress a state in which the open / close valve 17 is immersed in the generated water during the period when the system is stopped. Further, in order to remove the water from the on-off valve 17, it is not necessary to actively flow hydrogen into the separator tank 16 to discharge the generated water to the outside. Therefore, the on-off valve 17 is suppressed while preventing the discharge of excess gas. Can be prevented from freezing.

  In the above-described embodiment, the internal pressure of the separator tank 16 is reduced to the atmospheric pressure by controlling the purge valve 14 to the open state, but the present invention is not limited to this. For example, the inside of the separator tank 16 may be reduced to atmospheric pressure by consuming hydrogen in the hydrogen circulation system without opening the purge valve 14. In this case, the internal pressure of the separator tank 16 is indirectly monitored by referring to the supply pressure of hydrogen immediately before the system is shut down, the amount of output taken out by the output take-out device, the elapsed time of taking out the output, and the like. Also good. In this case, the relationship between the estimated value of the internal pressure of the separator tank 16 and individual parameters is obtained in advance as a map or table through experiments and simulations, and based on this, the internal space of the separator tank 16 is determined. It is desirable to estimate the pressure. Note that the atmospheric pressure that is the target value of the internal pressure of the separator tank 16 may be directly obtained and referred to by a sensor, or a representative value is prepared in consideration of the use environment. You may refer to

  Furthermore, in this embodiment, the inside of the separator tank 16 is depressurized to atmospheric pressure. Therefore, the liquid level in the upstream drainage flow path L13 is lowered, and the liquid level B in the separator tank 16 and the liquid level C in the upstream drainage flow path L13 are in an equilibrium state on the same horizontal plane. The layout of the on-off valve 17 is defined with reference to the liquid level C in the upstream drainage flow path L13. However, the present invention does not strictly require that the pressure is reduced to atmospheric pressure (external pressure on the open end side of the drainage channels L13 and L14). That is, if the pressure reduction control is performed so as to approach the atmospheric pressure without completely reducing the internal pressure of the separator tank 16 to the atmospheric pressure, the liquid level of the upstream drainage flow path L13 is lowered as shown in FIG. Although the liquid level B in the separator tank 16 and the liquid level C in the upstream drainage flow path L13 do not correspond on the same horizontal plane, both liquid levels are in an equilibrium state. Even in such a case, the opening / closing valve 17 is arranged above the liquid level of the generated water in the drainage flow paths L13, L14 after the opening / closing valve 17 is controlled to be in the open state as a freezing suppression process. When the system is stopped, the open / close valve 17 can be prevented from being immersed in the generated water. Thereby, freezing of the on-off valve 17 can be suppressed.

(Second Embodiment)
FIG. 6 is a configuration diagram schematically showing a drainage device 15A according to the second embodiment of the present invention. The difference between the drainage device 15A according to the second embodiment and the drainage device 15 according to the first embodiment is the shape of the drainage channel. In addition, the code | symbol is quoted about the structure similar to 1st Embodiment, and the overlapping description is abbreviate | omitted. The details of the freeze suppression process are the same as those in the first embodiment, and a description thereof will be omitted.

  The drainage device 15 </ b> A according to the second embodiment is mainly configured by a separator tank 16 and an opening / closing valve 17. In this embodiment, a part of the upstream drainage flow path L15 is provided inside the separator tank 16, extends vertically upward from the lower part of the water storage section 16c, and the level of generated water in the separator tank 16 More specifically, it is bent in the horizontal direction at the gas-liquid separator 16b. Thereafter, the upstream drainage flow path L15 extends to the outside of the separator tank 16, and is connected to the downstream drainage flow path L14 via the opening / closing valve 17. In the present embodiment, the downstream drainage flow path L14 extends in the horizontal direction, and the end thereof is open to the atmosphere. The open / close state of the open / close valve 17 is controlled by the control unit 30 as in the first embodiment.

  As described above, according to the drainage device 15A according to the present embodiment, the liquid level in the upstream drainage flow path L13 is lowered by controlling the open / close valve 17 to be in the open state as the freezing suppression process, so the first embodiment Has the same effect as. In addition, since a part of the upstream drainage flow path L13 is disposed inside the separator tank 16, the apparatus can be reduced in size and the mountability to the vehicle can be improved.

(Third embodiment)
FIG. 7 is a configuration diagram schematically showing a drainage device 15B according to the third embodiment of the present invention. The drainage device 15B according to the third embodiment is different from that of the first or second embodiment in that an upper limit value (upper limit water level) is set for the water level in the separator tank 16 (specifically, the water storage unit 16c). The control is performed by defining a lower limit value (lower limit water level). In addition, the code | symbol is quoted about the structure similar to 1st or 2nd embodiment, and the overlapping description is abbreviate | omitted.

  In the third embodiment, the control unit 30 controls the state of the open / close valve 17 based on the level of generated water in the water storage unit 16c of the separator tank 16 during normal operation of the fuel cell system. Specifically, when the water level of the generated water in the water storage unit 16c increases and reaches the upper limit water level set in advance to a value lower than the water level when the water storage unit 16c is full, the control unit 30 opens the open / close valve 17. Control the open state and start draining the generated water. Then, when the water level of the generated water reaches the lower limit water level (upper limit water level> lower limit water level), the control unit 30 controls the open / close valve 17 to be closed to end the drainage of the generated water. As a result, the generated water in the separator tank 16 falls within the range between the upper limit water level and the lower limit water level. The upper limit water level and the lower limit water level are, for example, water levels such that generated water does not flow into the gas-liquid separator 16b in consideration of fluctuations in the water level due to tilting or shaking caused by vehicle travel or the like (for example, when the vehicle is mounted). Is set as the upper limit water level, and the water level at which the produced water remains at the bottom of the water storage part 16c to the extent that the separated circulating gas is not discharged from the discharge port 16d is set as the lower limit water level.

  Further, water level detection sensors 31 and 32 are provided in the water storage section 16 c of the separator tank 16. The upper limit water level detection sensor 31 is a sensor that detects the upper limit water level in the water reservoir 16c, and the lower limit water level detection sensor 32 is a sensor that detects the lower limit water level in the water reservoir 16c. Detection results from the individual water level detection sensors 31 and 32 are output to the control unit 30.

  Further, in the present embodiment, as shown in FIG. 8, the volume Va of the upstream drainage flow path L13 is determined based on the volume of generated water in the separator tank 16 (water storage section 16c) at the time of full water, and the separator tank 16 at the upper limit water level. It is set to be smaller than a value (volume Vb) obtained by subtracting the volume of the generated water in (water reservoir 16c).

  FIG. 9 is a flowchart illustrating the procedure of the freeze suppression process according to the third embodiment. The process shown in this flowchart is invoked when the fuel cell system is stopped and executed by the control unit 30.

  First, in step 20 (S20), the on-off valve 17 is controlled to be in an open state. As described above, the hydrogen circulation flow path L11 including the internal space of the separator tank 16 is in a positive pressure state at the start of the freezing suppression process accompanying the system stop. Therefore, when the opening / closing valve 17 is controlled to be in the open state in Step 20, the generated water in the separator tank 16 is pushed out by the internal pressure and discharged to the outside through the drainage channels L13 and L14.

  In step 21 (S21), it is determined whether or not the generated water in the separator tank 16 has reached the reference water level. In the present embodiment, the reference water level is set to a lower limit water level for performing drainage control of the generated water in the separator tank 16. Therefore, the control unit 30 refers to the detection result of the lower limit water level detection sensor 32 and determines whether or not the generated water level has reached the lower limit water level.

  If an affirmative determination is made in step 21, that is, if the water level of the generated water has reached the lower limit water level, the process proceeds to step 22 (S22). On the other hand, if a negative determination is made in step 21, that is, if the water level of the generated water has not reached the lower limit water level, the process of step 21 is performed again after a predetermined time.

  In step 22 (S22), the on-off valve 17 is controlled to be closed. At step 23 (S23), atmospheric pressure control is performed in the same manner as the process at step S10 shown in the first embodiment, and at step 24 (S24), the process at step S11 shown in the first embodiment is performed. The opening / closing valve 17 is controlled to be open.

  As described above, according to this embodiment, the same effect as that of the first embodiment is obtained, and the level of the generated water in the separator tank 16 is set to the reference water level (in this embodiment, the lower limit water level) before the atmospheric pressure control. ), The amount of generated water that moves from the drainage flow path L13 to the separator tank 16 side increases. Therefore, since the liquid level drop width in the drainage flow path L13 becomes large, it is possible to suppress a situation in which the open / close valve 17 is immersed in the generated water. Thereby, freezing of the on-off valve 17 can be suppressed more effectively.

(Fourth embodiment)
FIG. 10 is a flowchart showing the procedure of the freeze suppression process according to the fourth embodiment of the present invention. Hereinafter, the number of freezing suppression processing procedures according to the fourth embodiment will be described. In addition, since the drainage apparatus concerning this embodiment is the same as that of 1st Embodiment, a code | symbol is quoted about the corresponding structure, and the overlapping description is abbreviate | omitted.

  First, in step 30 (S30), atmospheric pressure control is performed similarly to the process in step 10 shown in the first embodiment, and in step 31 (S31), the same process as in step 11 shown in the first embodiment is performed. The opening / closing valve 17 is controlled to be open.

  In step 32 (S32), it is determined whether or not removal of the generated water in the on-off valve 17 is completed. In the present embodiment, the determination as to whether or not the generated water has been removed is made based on the elapsed time since the open / close valve 17 was controlled to the open state. Therefore, through experiments and simulations, on the premise of atmospheric pressure control and open / close valve 17 open control, the time required for removing generated water from the open / close valve 17 is obtained as a reference time, and the reference time and elapsed time are obtained. Judgment will be made by comparison with.

  If an affirmative determination is made in step 32, that is, if the time since the opening / closing valve 17 has been opened has reached the reference time, the routine proceeds to step 33 (S33). On the other hand, if a negative determination is made in step 32, that is, if the time from when the on-off valve 17 is closed has not reached the reference time, the process of step 32 is performed again after a predetermined time.

  In step 33, the open / close valve 17 is controlled to be closed, and this routine is terminated.

  As described above, according to the present embodiment, the open / close valve 17 is finally controlled to be closed after the open / close valve 17 is controlled to be open. For this reason, it is possible to suppress the inconvenience that foreign matters or the like are mixed into the separator tank 16 through the drainage channels L13 and L14.

(Fifth embodiment)
FIG. 11 is a configuration diagram schematically showing a drainage device 15C according to the fifth embodiment of the present invention. The drainage device 15C according to the fifth embodiment is different from that of each embodiment described above in that a water level detection sensor is provided in the upstream drainage flow path L13. In addition, the code | symbol is quoted about the structure similar to each embodiment mentioned above, and the overlapping description is abbreviate | omitted.

  Specifically, a water level detection sensor 33 is provided downstream of the open / close valve 17 in the upstream drainage flow path L13. The detection result from the water level detection sensor 33 is output to the control unit 30. The water level detection sensor 33 is disposed above the level of the generated water in the drainage flow path L13 after the open / close valve 17 is controlled to be in the open state as a freeze suppression process.

  In the present embodiment, the upstream drainage flow path L13 is provided with an orifice 18 that reduces the flow path diameter at a position in contact with the open / close valve 17.

  In the drainage device 15C having such a configuration, the control unit 30 performs atmospheric pressure control, and then controls the open / close valve 17 to be in an open state. Then, the control unit 30 refers to the detection result of the water level detection sensor 33, and closes the opening / closing valve 17 on the condition that the liquid level of the upstream drainage flow path L13 has decreased and the liquid level has reached the sensor position. Control to the state.

  As described above, according to the present embodiment, since the on-off valve 17 is finally controlled to be in the closed state, it is possible to suppress the entry of foreign matters and the like. Further, when the liquid level is lowered to the position of a water level detection sensor 33 provided downstream of the opening / closing valve 17, that is, before the liquid level between the separator tank 16 and the upstream drainage flow path L13 is in an equilibrium state, the opening / closing valve. Since 17 can be closed, the processing time can be shortened.

  Further, since the orifice 18 is provided in contact with the opening / closing valve 17, when the opening / closing valve 17 is controlled to be in the open state, the orifice 18 is not submerged by the generated water. Therefore, since the time for the generated water to move to the separator tank 16 is shortened, the processing time can be further shortened.

(Sixth embodiment)
FIG. 12 is a configuration diagram schematically showing a drainage device 15D according to the sixth exemplary embodiment of the present invention. The difference between the drainage device 15D according to the sixth embodiment and that of each embodiment described above is the shape of the drainage flow path. In addition, the code | symbol is quoted about the structure similar to the above, and the overlapping description is abbreviate | omitted. The details of the freeze suppression process are the same as those in the first embodiment, and a description thereof will be omitted.

  A drainage device 15D according to the sixth embodiment mainly includes a separator tank 16 and an opening / closing valve 17. At the lower part of the main body of the separator tank 16, a discharge port 16d that is an opening for discharging the generated water stored in the water storage section 16c is formed, and an upstream drainage flow path L13 is connected to the discharge port 16d. ing. This upstream drainage flow path L13 is connected to the downstream drainage flow path L14 via the open / close valve 17, and the generated water in the water storage section 16c is circulated on the condition that the open / close valve 17 is open. Due to the internal pressure of the system, that is, the separator tank 16, it is discharged to the outside through the upstream drainage flow path L13 and the downstream drainage flow path L14. In the present embodiment, the upstream drainage flow path L13 bends and extends in the horizontal direction after extending vertically downward, and then bends and extends vertically upward. In addition, when the upstream drainage flow path L13 extends above the level of the generated water in the separator tank 16, that is, in this embodiment, to a position corresponding to the gas-liquid separation portion 16b, it is then bent to the horizontal direction. And extend. Then, it is bent downward in the vertical direction and connected to the downstream drainage flow path L14 via an opening / closing valve 17 provided at the open end portion. In the present embodiment, the downstream drainage flow path L14 has a shape extending downward, and its end is open to the atmosphere. The open / close state of the open / close valve 17 is controlled by the control unit 30.

  Thus, in the present embodiment, the upstream drainage flow path L13 has a bent shape in which a part of the flow path extends upward and extends downward via the bent portion, and the separator tank 16 After the internal generated water is guided upward from the surface of the generated water, it is discharged from the end opened to the outside. According to this configuration, the downstream drainage flow path L14 has a downward-facing shape and the generated water existing in the vicinity of the on-off valve 17 is discharged out of the system by its own weight while exhibiting the operations and effects shown in the first embodiment. It looks like this. Thereby, since retention of the generated water of the on-off valve 17 can be suppressed, freezing of the on-off valve 17 can be effectively suppressed.

  In each of the embodiments described above, the embodiment in which the drainage device is applied to the hydrogen system 10 has been described. However, the present invention is not limited to this, and the drainage device can also be applied to the air system 20. Moreover, the drainage device described in each embodiment can be applied not only in the combination described in the above-described embodiment but also in various combinations of the characteristic points within the scope of the invention.

The block diagram which shows the structure of the fuel cell system concerning embodiment of this invention. The block diagram which shows typically the drainage device 15 concerning 1st Embodiment The flowchart which shows the procedure of the freezing suppression process concerning 1st Embodiment. Explanatory drawing which shows the movement state of the produced water by freezing suppression processing Explanatory drawing which shows the movement state of the produced water by freezing suppression processing The block diagram which shows typically 15 A of drainage apparatuses concerning 2nd Embodiment The block diagram which shows typically the drainage device 15B concerning 3rd Embodiment Explanatory drawing of volume Va of upstream drainage flow path L13 The flowchart which shows the procedure of the freezing suppression process concerning 3rd Embodiment. The flowchart which shows the procedure of the freezing suppression process concerning 4th Embodiment. The block diagram which shows typically 15 C of drainage apparatuses concerning 5th Embodiment The block diagram which shows typically drainage apparatus 15D concerning 6th Embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell stack 10 Hydrogen system 11 Fuel tank 12 Hydrogen pressure regulation valve 13 Circulation pump 14 Purge valve 15 Drainage device 16 Separator tank 16a Partition plate 16b Gas-liquid separation part 16c Water storage part 16d Discharge port 17 Open / close valve 18 Orifice 20 Air system 21 Compressor 22 Humidifier 23 Air pressure regulating valve 30 Control unit 31 Upper limit water level detection sensor 32 Lower limit water level detection sensor 33 Water level detection sensor L10 Hydrogen supply channel L11 Hydrogen circulation channel L12 Hydrogen discharge channel L13 Upstream drain channel L14 Downstream drain channel L20 Air supply flow path L21 Air discharge flow path

Claims (9)

In a drainage device for draining water in a fuel cell system comprising a fuel cell that generates electric power by electrochemically reacting a fuel gas and an oxidant gas,
Water storage means for storing generated water accompanying the power generation of the fuel cell;
A part of the flow path has an upward shape extending upward, and after the generated water inside the water storage means is guided upward from the liquid level of the generated water, the end opened to the outside Drainage flow path discharging from the section,
An opening / closing means provided in the drainage channel to open and close the channel;
Pressure adjusting means for adjusting the internal pressure of the water storage means;
Control means for controlling the opening and closing means and the pressure adjusting means,
The control means, when stopping the system in the fuel cell system, with the external pressure on the open end side of the drainage flow path as a target value, the internal pressure of the water storage means is reduced by the pressure adjusting means, Freezing suppression processing for controlling the opening and closing means to the open state,
The drainage device, wherein the opening / closing means is disposed above the level of the produced water in the drainage flow channel in a state where the freeze suppression process is performed. In a drainage device for draining water in a fuel cell system comprising a fuel cell that generates electric power by electrochemically reacting a fuel gas and an oxidant gas,
Water storage means for storing generated water accompanying the power generation of the fuel cell;
A part of the flow path extends upward and has a bent shape extending downward via a bent portion, and the generated water inside the water storage means is above the level of the generated water. A drainage channel that discharges from the end opened to the outside after being led to
Opening / closing means provided on the open end side of the drainage flow channel than the bent portion, for opening and closing the flow channel,
Pressure adjusting means for adjusting the internal pressure of the water storage means;
Control means for controlling the opening and closing means and the pressure adjusting means,
The control means, when stopping the system in the fuel cell system, with the external pressure on the open end side of the drainage flow path as a target value, the internal pressure of the water storage means is reduced by the pressure adjusting means, Freezing suppression processing for controlling the opening and closing means to the open state,
The drainage device, wherein the bent portion is positioned above the level of the generated water in the drainage flow channel in the state where the freeze suppression process is performed.   The control means controls the open / close means to be in an open state so that the level of the generated water in the drainage channel and the level of the generated water in the water storage means are in equilibrium with each other. The drainage device according to claim 1 or 2, wherein the internal pressure of the water storage means is reduced. Further comprising first water level detection means for detecting the level of generated water stored in the water storage means;
In the normal operation of the system, the control means reaches the upper limit water level set to a value lower than the water level when the water storage means is full based on the detection result of the first water level detection means. When the generated water level reaches a lower limit water level set to a value lower than the upper limit water level, the opening / closing means The drainage device according to any one of claims 1 to 3, wherein the drainage of the generated water is terminated by controlling the valve to a closed state.   In the drainage channel, the volume of the channel upstream of the opening / closing unit is obtained by subtracting the volume of the generated water inside the water storage unit at the upper limit water level from the volume of the generated water inside the water storage unit when the water is full. The drainage device according to claim 4, wherein the drainage device is set smaller than the value.   The control means controls the open / close means to an open state on the premise that the freeze suppression process is performed, and the generated water in the water storage means is preset based on the detection result of the first water level detection means. The drainage device according to any one of claims 1 to 5, wherein the opening / closing means is controlled to be in a closed state on condition that the reference water level is reached.   The said control means controls the said opening / closing means from an open state to a closed state, after controlling the said opening / closing means to an open state as the said freeze suppression process, The any one of Claim 1 to 6 characterized by the above-mentioned. Drainage equipment. A second water level detection means provided on the water storage means side of the open / close means in the drainage flow path;
The control means controls the opening / closing means from an open state to a closed state on condition that the liquid level in the drainage channel has decreased to a reference water level detected by the second water level detection means. The drainage device according to claim 7 characterized by things.   The drainage device according to any one of claims 1 to 8, further comprising an orifice provided at a position in contact with the opening / closing means in the drainage channel to reduce the channel diameter.

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