JP2008262735A - Fuel cell system, and control method of discharge valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively suppress mixing of gas to draining liquid in a fuel cell system storing water generated in a fuel cell in a water storing part and discharging it from a discharge valve to the outside. <P>SOLUTION: The fuel cell system 1 is equipped with a fuel cell 2; the water storing part 40 storing water discharged from the fuel cell 2; the discharge valve 31 installed on the downstream side of an discharge port 41 installed in the water storing part 40; and a control means 5 controlling the discharge valve 31; and furthermore equipped with an acceleration detecting means 6 detecting acceleration Au of the water storing part 40, and the control means 5 decides whether water in the water storing part 40 is in a position capable of discharging from the discharging port or not based on the acceleration Au of the water storing part 40 detected with the acceleration detecting means 6, and controls opening and closing of the discharge valve 31 based on a result of decision. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell system and a discharge valve control method.

  2. Description of the Related Art Conventionally, a fuel cell system including a fuel cell that generates power by receiving a supply of reaction gas (fuel gas and oxidizing gas) has been proposed and put into practical use. In such a fuel cell system, with power generation, impurities such as nitrogen and carbon monoxide and moisture accumulate with time in the inside of the fuel cell and in the circulation path of the fuel off gas. Therefore, a technique (purge technique) for discharging impurities and moisture to the outside by providing a gas-liquid separator in the circulation flow path of the fuel cell system and opening a discharge valve connected to the gas-liquid separator has been proposed. Yes.

In recent years, there has been proposed a technique for controlling the discharge of gas and moisture from a discharge valve by calculating the water level of water stored in a water storage container of a gas-liquid separator (see Patent Document 1). In such a technique, the water level in the water storage container is calculated based on the differential pressure between the water pressure in the water storage container (or in the drain pipe) and the gas pressure on the water surface. The mixing of gas is suppressed.
JP 2006-139957 A

  By the way, in order to more reliably suppress the mixing of gas into the drainage discharged from the water storage container to the outside, the drain outlet, which is the connection between the drain pipe and the water storage container, appears on the water surface or is hidden under the water surface. It is necessary to judge whether it is correct.

  However, when the fuel cell system is mounted on a moving body such as a vehicle, due to acceleration / deceleration or turning of the moving body, an inertial force corresponding to the acceleration acts on the stored water in the water storage container. The stored water in the container moves according to the direction and magnitude of this inertial force, and the water surface is inclined. Therefore, in order to accurately determine whether or not the connection portion between the drain pipe and the water storage container is hidden under the water surface, it is necessary to calculate the water level in the water storage container in consideration of the inclination of the water surface due to the acceleration of the moving body. .

  Patent Document 1 described above does not describe a method for calculating the water level in consideration of the inclination of the water surface caused by acceleration / deceleration or turning of the moving body. For this reason, when adopting the conventional technique described in Patent Document 1 described above, it is possible to accurately determine whether or not the connecting portion between the drain pipe and the water storage container is hidden under the water surface during acceleration / deceleration or turning of the vehicle. It was difficult and there was a possibility that gas would be mixed into the waste water.

  The present invention has been made in view of such circumstances, and in a fuel cell system in which water generated in a fuel cell is stored in a reservoir and discharged to the outside by a discharge valve, gas is effectively mixed into the drainage. The purpose is to suppress.

  In order to achieve the above object, a fuel cell system according to the present invention includes a fuel cell, a water storage part for storing water discharged from the fuel cell, and a discharge disposed downstream of a drain outlet provided in the water storage part. A fuel cell system comprising a valve and a control means for controlling the discharge valve, comprising an acceleration detection means for detecting the acceleration of the water storage section, wherein the control means is based on the acceleration of the water storage section detected by the acceleration detection means. It is determined whether or not the water in the water storage section is at a position where it can be discharged from the drain outlet, and the opening and closing of the discharge valve is controlled based on the determination result.

  When such a configuration is adopted, it is determined whether or not water is in a position where water can be discharged from the drain port when water is moving in the reservoir due to the generation of inertia force based on acceleration, and the discharge valve is based on the result. Therefore, it is possible to effectively suppress the mixing of gas into the waste water. Therefore, it is possible to suppress wasteful discharge of gas to be circulated to the fuel cell (fuel gas that contributes to power generation), and to reduce drainage control error in the purge operation.

  In the fuel cell system, it is determined whether or not the discharge port is hidden under the water surface based on the acceleration of the water storage unit, and when the discharge port is hidden under the water surface, the discharge valve is allowed to open and the discharge port is opened. Control means for prohibiting the opening of the discharge valve when the outlet is not hidden below the water surface can be employed.

  When such a configuration is adopted, when the discharge port is not hidden under the water surface, the discharge valve is not opened, so that mixing of gas into the waste water can be effectively suppressed.

  In the fuel cell system, a discharge port can be provided on a side surface of the water storage section. Moreover, the water storage container provided in the gas-liquid separator which isolate | separates water from the fuel off gas discharged | emitted from a fuel cell as a water storage part is employable. Further, as the discharge valve, an exhaust / drain valve that discharges water and fuel off-gas in the water reservoir can be adopted.

  The fuel cell system can be mounted on a moving body. In such a case, it is possible to employ acceleration detection means for detecting the acceleration of the water storage section that occurs with the linear motion and / or the turning motion of the moving body.

  When such a configuration is adopted, it is possible to suppress gas from being mixed into the waste water of the moving body on which the fuel cell system is mounted. Accordingly, it is possible to suppress wasteful discharge of gas (fuel gas) to be circulated to the fuel cell, thereby improving the fuel consumption rate of the moving body (reducing fuel consumption per unit moving distance). It becomes possible.

  In the fuel cell system, acceleration detecting means for detecting linear acceleration generated along with the linear motion of the moving body can be employed. In such a case, it is determined whether or not the water in the water reservoir is in a position where it can be discharged from the drainage port based on the acceleration in the linear direction, and a control means for controlling the opening and closing of the discharge valve based on the determination result is adopted. can do.

  In the fuel cell system, it is possible to employ acceleration detecting means for detecting acceleration in the direction of centrifugal force generated with the turning motion of the moving body. In such a case, it is determined whether or not the water in the reservoir is in a position where it can be discharged from the drain outlet based on the acceleration in the centrifugal force direction, and control means for controlling the opening and closing of the discharge valve based on the determination result. Can be adopted.

  In the fuel cell system, it is possible to employ acceleration detecting means for detecting acceleration in the linear direction and the centrifugal force direction generated along with the linear motion and the turning motion of the moving body. In such a case, it is determined whether or not the water in the reservoir is in a position where it can be discharged from the drain outlet based on the acceleration in the linear direction and the centrifugal force direction, and the opening and closing of the discharge valve is controlled based on the determination result. Control means can be employed.

  The fuel cell system may further include water amount estimation means for estimating the amount of water stored in the water storage unit based on the power generation amount of the fuel cell. In such a case, it is determined whether or not the water in the water reservoir is in a position where it can be discharged from the drain outlet based on the acceleration of the water reservoir detected by the acceleration detector and the amount of water estimated by the water amount estimator. In addition, it is possible to employ control means for controlling the opening and closing of the discharge valve based on the result of the determination.

  In addition, a control method according to the present invention includes a fuel cell, a water storage unit that stores water discharged from the fuel cell, and a discharge valve that is disposed downstream of a drain port provided in the water storage unit. A method for controlling a discharge valve in a battery system, wherein an acceleration detection step for detecting the acceleration of the water storage portion and whether water in the water storage portion is at a position where the water can be discharged from the drain outlet based on the acceleration detected in the acceleration detection step. A water level determination step for determining whether or not, and a valve control step for controlling the opening and closing of the discharge valve based on the determination result in the water level determination step.

  When such a method is adopted, it is determined whether or not water is in a position where water can be discharged from the drain outlet when water is moving in the reservoir due to the generation of inertial force based on acceleration, and the discharge valve is based on the result. Therefore, it is possible to effectively suppress the mixing of gas into the waste water. Therefore, it is possible to suppress wasteful discharge of gas to be circulated to the fuel cell (fuel gas that contributes to power generation), and to reduce drainage control error in the purge operation.

  The control method can be applied to a discharge valve control method in a fuel cell system mounted on a moving body. In such a case, in the acceleration detection step, it is possible to detect the acceleration generated in the water storage part with the linear motion and / or the turning motion of the moving body.

  When such a method is employed, it is possible to prevent gas from being mixed into the waste water of the moving body equipped with the fuel cell system. Accordingly, it is possible to suppress wasteful discharge of gas (fuel gas) to be circulated to the fuel cell, thereby improving the fuel consumption rate of the moving body (reducing fuel consumption per unit moving distance). It becomes possible.

  ADVANTAGE OF THE INVENTION According to this invention, in the fuel cell system which stores the water which generate | occur | produced in the fuel cell in the water storage part, and discharges it outside by a discharge valve, it becomes possible to suppress effectively mixing of the gas to waste_water | drain.

  Hereinafter, a fuel cell system 1 according to an embodiment of the present invention will be described with reference to the drawings. The fuel cell system 1 of the present invention is an on-vehicle power generation system mounted on a fuel cell vehicle (moving body) S as shown in FIG.

  As shown in FIG. 2, the fuel cell system 1 according to the present embodiment includes a fuel cell 2 that generates power upon receiving supply of reaction gas (oxidation gas and fuel gas), and air as the oxidation gas. Oxidant gas piping system 3 supplied to the fuel cell, a fuel gas piping system 4 for supplying hydrogen gas as a fuel gas to the fuel cell 2, a control device 5 for overall control of the entire system, and the acceleration of the fuel cell vehicle S are detected. And an acceleration sensor 6.

  The fuel cell 2 is formed of, for example, a solid polymer electrolyte type and has a stack structure in which a large number of single cells are stacked. The unit cell of the fuel cell 2 has a pair of separators having an air electrode on one surface of an electrolyte made of an ion exchange membrane, a fuel electrode on the other surface, and further sandwiching the air electrode and the fuel electrode from both sides. have. The fuel gas is supplied to the fuel gas flow path of one separator and the oxidizing gas is supplied to the oxidizing gas flow path of the other separator, and the fuel cell 2 generates electric power by this gas supply.

  The oxidizing gas piping system 3 has an air supply passage 11 through which oxidizing gas supplied to the fuel cell 2 flows, and an exhaust passage 12 through which oxidizing off-gas discharged from the fuel cell 2 flows. The air supply flow path 11 is provided with a compressor 14 that takes in the oxidizing gas via the filter 13 and a humidifier 15 that humidifies the oxidizing gas fed by the compressor 14. Oxidized off-gas flowing through the exhaust passage 12 is supplied to the moisture exchange by the humidifier 15 through the back pressure regulating valve 16, and then merged with the hydrogen off-gas in a diluter (not shown) to finally dilute the hydrogen off-gas. The exhaust gas is exhausted into the atmosphere outside the system. The compressor 14 takes in the oxidizing gas in the atmosphere by driving a motor (not shown).

  The fuel gas piping system 4 includes a hydrogen supply source 21, a hydrogen supply passage 22 through which hydrogen gas supplied from the hydrogen supply source 21 to the fuel cell 2 flows, and a hydrogen offgas (fuel offgas) discharged from the fuel cell 2. A circulation channel 23 for returning to the junction A1 of the hydrogen supply channel 22, a hydrogen pump 24 for pumping the hydrogen off-gas in the circulation channel 23 to the hydrogen supply channel 22, and a branch connection to the circulation channel 23 And an exhaust drainage channel 25.

  The hydrogen supply source 21 is configured by a high-pressure gas tank capable of storing hydrogen gas at a predetermined pressure (for example, 35 MPa or 70 MPa). The hydrogen supply source 21 is composed of a reformer that generates a hydrogen-rich reformed gas from a hydrocarbon-based fuel and a high-pressure gas tank that stores the reformed gas generated by the reformer in a high-pressure state. May be. In addition, a tank having a hydrogen storage alloy can be employed as the hydrogen supply source 21.

  The hydrogen supply channel 22 includes a shutoff valve 26 that shuts off or allows the supply of hydrogen gas from the hydrogen supply source 21, a pressure regulating valve 27 that adjusts the pressure of the hydrogen gas, and an electromagnetically driven on-off valve 28. Is provided. On the upstream side of the on-off valve 28, a pressure sensor and a temperature sensor (not shown) for detecting the pressure and temperature of the hydrogen gas in the hydrogen supply passage 22 are provided. A pressure sensor (not shown) is also provided between the on-off valve 28 and the merging portion A1. Information on the gas state (pressure, temperature) of the hydrogen gas detected by these sensors is used for hydrogen gas supply control and purge control. The pressure regulating valve 27 reduces the gas pressure of the hydrogen gas to a preset secondary pressure. The on-off valve 28 is driven and controlled by a control signal transmitted from the control device 5 and adjusts the flow rate and gas pressure of hydrogen gas supplied to the hydrogen supply flow path 22 side with high accuracy.

  The hydrogen gas circulation system is constituted by a downstream channel of the junction A1 of the hydrogen supply channel 22, a fuel gas channel formed in the separator of the fuel cell 2, and a circulation channel 23. Become. The hydrogen pump 24 circulates and supplies the hydrogen gas in the circulation system to the fuel cell 2 by driving a motor (not shown).

  An exhaust / drain channel 25 is connected to the circulation channel 23 via a gas / liquid separator 30 and an exhaust / drain valve 31. The gas-liquid separator 30 collects moisture from the hydrogen off gas, and has a water storage container 40 (FIG. 3) described later. The exhaust / drain valve 31 operates according to a command from the control device 5 to discharge moisture collected by the gas-liquid separator 30 and hydrogen off-gas (fuel off-gas) containing impurities in the circulation channel 23 to the outside. (Purge) is an embodiment of the discharge valve in the present invention. In this embodiment, the water storage container 40 of the gas-liquid separator 30 is mounted in a fixed state on the fuel cell vehicle S, and the acceleration generated in the fuel cell vehicle S is generated in the water storage container 40 as it is. .

  By opening the exhaust / drain valve 31, the concentration of impurities in the hydrogen off-gas in the circulation passage 23 decreases, and the hydrogen concentration in the hydrogen off-gas supplied in circulation increases. The hydrogen off-gas discharged to the outside through the exhaust / drain valve 31 and the exhaust / drain passage 25 is separated from the oxidizing off-gas (air) in the exhaust passage 12 in a diluter (not shown) provided downstream of the exhaust / drain valve 31. Merge and dilute.

  The control device 5 receives control information such as an accelerator signal (required load) of a vehicle (not shown) and controls operations of various devices in the system. The control device 5 is configured by a computer system (not shown). Such a computer system includes a CPU, ROM, RAM, HDD, input / output interface, display, and the like, and various control operations are realized by the CPU reading and executing various control programs recorded in the ROM. .

  Detection information of each sensor that detects the pressure, temperature, flow rate and the like of the fluid flowing through each piping system is input to the control device 5. The control device 5 calculates the flow rate of the reaction gas to be supplied to the fuel cell 2 according to the detection information and the required power generation amount in the fuel cell 2, and the target of the hydrogen off gas to be discharged from the exhaust drain valve 31. The discharge amount (target purge amount) is calculated. The control device 5 controls the operation of various devices in the system, and performs various processes and controls such as supply of reactive gas into the fuel cell 2 and purge control. In FIG. 2, only the control signal to the exhaust / drain valve 31 and the detection signal from the acceleration sensor 6 are displayed, and the other control signals and detection signals are not shown.

  Information relating to the acceleration generated in the fuel cell vehicle S (and the water storage container 40 of the gas-liquid separator 30) is input from the acceleration sensor 6 to the control device 5. The fuel cell vehicle S is provided with a vehicle speed sensor (not shown). When the fuel cell vehicle S is traveling straight, the acceleration sensor 6 obtains the rate of change of the vehicle speed from the detection information of the vehicle speed sensor. The acceleration Au (FIG. 4) in the traveling direction (linear direction) is detected. Further, when the fuel cell vehicle S is turning, the acceleration sensor 6 obtains a lateral acceleration (acceleration in the direction of centrifugal force) Av by obtaining a torque generated in the steering system of the fuel cell vehicle S and a rate of change of the steering angle. (FIG. 5) is detected. In addition, the acceleration sensor 6 can detect both linear acceleration (Au) and centrifugal acceleration (Av) when performing a combined straight and turning motion. The acceleration Au and lateral acceleration Av detected by the acceleration sensor 6 are used for opening / closing control of the exhaust / drain valve 31 as will be described later. The acceleration sensor 6 is an embodiment of the acceleration detection means in the present invention.

  The control device 5 opens and closes the exhaust drain valve 31 at a predetermined timing, thereby discharging unnecessary moisture in the circulation flow path 23 collected by the gas-liquid separator 30 to the outside, and at the target purge amount of hydrogen off gas. Purge control is performed to discharge the air to the outside. In this purge control, when the inertia force due to the acceleration of the vehicle is generated in the purge control, the control device 5 is in the state of the water stored in the gas-liquid separator 30, that is, the water retention position in the water storage container 40 described later. Based on the above, control is performed to permit or prohibit the opening of the exhaust / drain valve 31. That is, the control device 5 functions as an embodiment of the control means in the present invention. The details will be described below.

  3A and 3B are cross-sectional views of a water storage container 40 as a water storage section provided in the gas-liquid separator 30. FIG. 3A is a cross-sectional view of the water storage container 40 in the vehicle front-rear direction, and FIG. 3B is a cross-sectional view of the water storage container 40 in the vehicle width direction. In FIG. 3, the dimension of the water storage container 40 in the vehicle front-rear direction is indicated by U, and the dimension in the vehicle width direction is indicated by V. In addition, this figure shows the structure of the water storage container 40 roughly, and the upper part and detail of the water storage container 40 are abbreviate | omitted.

  The water storage container 40 in the present embodiment is a substantially rectangular parallelepiped, and is mounted on the fuel cell vehicle S so that the bottom surface thereof and the horizontal plane substantially coincide. The exhaust / drain valve 31 is not located below the water storage container 40 but on the side. The water storage container 40 has a drain port 41 that opens at the lower side of the side of the vehicle side (the vehicle right side in the present embodiment), and the exhaust drainage channel 25 is connected to the drain port 41 from the side. It has become. The water discharged from the drain port 41 flows into the exhaust drain valve 31 provided in the exhaust drain passage 25. The center position of the drain port 41 is the same height as the bottom surface of the water storage container 40, and the distance from the side surface on the vehicle rear side is indicated by Ua.

  Water collected from the hydrogen off-gas in the circulation channel 23 is introduced into the water storage container 40 from an inlet (not shown) provided in the upper part thereof. The introduced water is collected at the bottom of the water storage container 40. FIG. 3 shows a state where no acceleration is generated in the fuel cell vehicle S, for example, a state of water when the fuel cell vehicle S is stopped or moving at a constant speed. At this time, since the acceleration acting on the water in the water storage container 40 is only the gravitational acceleration g, the water surface is horizontal.

  Hereinafter, control of the exhaust / drain valve 31 in a state where acceleration is generated in the fuel cell vehicle S will be described.

  First, control when the vehicle goes straight will be described. FIG. 4 shows a state in the water storage container 40 when the fuel cell vehicle S travels linearly while accelerating at the acceleration Au. As shown in this figure, when the fuel cell vehicle S is accelerated at the acceleration Au, in addition to gravity, the inertia force corresponding to the acceleration Au is opposite to the direction of the acceleration Au in the water in the water storage container 40 (vehicle Occurs backward). In this case, the water in the water storage container 40 receives the resultant force of inertia and gravity and moves to the vehicle rear side, so that the water surface is inclined. The inclination θu of the water surface is an angle calculated based on the following equation (1), and the water surface is inclined from the rear side of the vehicle toward the front side of the vehicle. In Equation (1), “Gu” is an apparent acceleration generated toward the rear of the vehicle as the fuel cell vehicle S accelerates, and is equal to the magnitude of the acceleration Au.

  When the inertia force is large and the water surface inclination θu is large, water stays only on the vehicle rear side of the water storage container 40, and the bottom surface of the water storage container 40 is exposed on the vehicle front side. If the position of the boundary between the area where the bottom surface of the water storage container 40 is not hidden below the water surface and the area where the water storage container 40 is hidden is a position u from the side surface on the vehicle rear side, and the amount of water in the water storage container 40 is Q, Q is It is calculated by the following formula (2). And based on Formula (1) and Formula (2), the distance u is calculated by the following Formula (3).

  In the formula (3), “V” and “g” are constants. Therefore, the control device 5 can calculate u based on the amount of water Q stored in the water storage container 40 and the apparent acceleration Gu (= Au) acting on the water in the water storage container 40. The control device 5 in the present embodiment estimates the water amount Q stored in the water storage container 40 based on the power generation amount of the fuel cell 2. That is, the control device 5 also functions as water amount estimation means in the present invention.

  Next, the control device 5 determines whether or not the water staying in the water storage container 40 is in a position where it can be discharged from the drain port 41 in order to determine whether or not to allow the exhaust drain valve 31 to be opened. I do. As shown in FIG. 4, when the fuel cell vehicle S is accelerating, this determination can be made according to a determination formula of “u> Ua”. Based on this determination formula, the control device 5 determines whether or not the water in the water storage container 40 is in a position where it can be discharged from the drain port 41, and opens and closes the exhaust drain valve 31 based on the determination result. Control.

  Specifically, when the determination formula “u> Ua” is satisfied, the control device 5 determines that the drain port 41 is below the water surface and allows the exhaust drain valve 31 to be opened. Thereby, only water can be discharged from the drain port 41. On the other hand, when the determination formula “u> Ua” is not satisfied, the control device 5 determines that the drain port 41 is at the same height as or above the water surface and prohibits the exhaust drain valve 31 from being opened. This is because if the exhaust / drain valve 31 is opened in a state where the determination formula “u> Ua” is not satisfied, water can be discharged temporarily, but hydrogen off-gas is mixed or only hydrogen off-gas is discharged.

  Next, control during vehicle turning will be described. FIG. 5 shows a state in the water storage container 40 when the fuel cell vehicle S is turning clockwise. As shown in this figure, when the fuel cell vehicle S turns to generate a lateral acceleration Av in the water storage container 40, the water in the water storage container 40 has an inertial force (centrifugal) corresponding to the lateral acceleration Av in addition to gravity. Force) is generated in the direction opposite to the direction of the lateral acceleration Av (toward the left side of the vehicle). In this case, the water in the water storage container 40 receives the resultant force of inertia and gravity, moves to the left side of the vehicle, and the water surface is inclined. The water surface inclination θv is an angle calculated based on the following equation (4), and is inclined so that the position of the water surface decreases from the left side of the vehicle toward the right side of the vehicle. In equation (4), “Gv” is an apparent acceleration generated toward the left side of the vehicle as the fuel cell vehicle S turns right, and is equal to the magnitude of the lateral acceleration Av.

  When the centrifugal force is large and the water surface inclination θv is large, water stays only on the vehicle left side of the water storage container 40, and the bottom surface of the water storage container 40 is exposed on the vehicle right side. When the position of the boundary between the area where the bottom surface of the water storage container 40 is not hidden below the water surface and the area where the water storage container 40 is hidden is a position v from the side surface on the left side of the vehicle, and the amount of water in the water storage container 40 is Q, Q is (5). And based on Formula (4) and Formula (5), the distance v is calculated by the following Formula (6).

  In Expression (6), “U” and “g” are constants. Therefore, the control device 5 can calculate v based on the amount of water Q stored in the water storage container 40 and the apparent acceleration Gv (= Av) acting on the water in the water storage container 40.

  Next, the control device 5 determines whether or not the water staying in the water storage container 40 is in a position where it can be discharged from the drain port 41 in order to determine whether or not to allow the exhaust drain valve 31 to be opened. I do. Since the drain port 41 is provided at the lower end of the side surface on the right side of the vehicle, the determination when the fuel cell vehicle S is turning clockwise can be performed by a determination formula of “v> V”. Based on this determination formula, the control device 5 determines whether or not the water in the water storage container 40 is in a position where it can be discharged from the drain port 41, and opens and closes the exhaust drain valve 31 based on the determination result. Control.

  Specifically, when the determination formula “v> V” is satisfied, the control device 5 determines that the drain port 41 is below the water surface and allows the exhaust drain valve 31 to be opened. Thereby, only water can be discharged from the drain port 41. On the other hand, when the determination formula “v> V” is not satisfied, the control device 5 determines that the drain port 41 is at the same height as or above the water surface and prohibits the exhaust drain valve 31 from being opened. This is because if the exhaust drain valve 31 is opened in a state where the determination formula “v> V” is not satisfied, water can be discharged temporarily, but hydrogen off gas is mixed in or only hydrogen off gas is discharged.

  Next, the control in the case where the fuel cell vehicle S performs a combined straight and turning motion will be described. In such a case, the control device 5 determines the above-described determination formula (“u>” based on both the acceleration in the linear direction (acceleration Au) and the acceleration in the centrifugal force direction (lateral acceleration Av) detected by the acceleration sensor 6. Ua ”and“ v> V ”) are satisfied. Then, the control device 5 allows the exhaust / drain valve 31 to be opened only when both of the two determination expressions are satisfied, and prohibits the exhaust / drain valve 31 from being opened when any one of them is not satisfied.

  Next, a control method of the exhaust / drain valve 31 in which each of the above controls is performed will be described using the flowchart of FIG.

  First, the control device 5 uses the acceleration sensor 6 to detect linear acceleration (acceleration Au) and centrifugal force acceleration (lateral acceleration Av) generated in the fuel cell vehicle S (water storage container 40) (acceleration). Detection step: S1).

  Next, when the fuel cell vehicle S is accelerating in the linear direction, the control device 5 determines the water amount Q in the water storage container 40 estimated based on the power generation amount of the fuel cell 2 and the acceleration detected in the acceleration detection step S1. Based on Au, it is determined whether or not the determination formula “u> Ua” is satisfied. Further, when the control device 5 is turning right, whether or not the determination formula of “v> V” is satisfied based on the estimated water amount Q and the lateral acceleration Av detected in the acceleration detection step S1 is determined. Is determined (water level determination step: S2). These determinations mean determination of whether or not the water in the water storage container 40 is in a position where it can be discharged from the drain port 41 (that is, whether or not the drain port 41 is hidden under the water surface) as described above. . Note that the control device 5 does not determine “u> Ua” when the acceleration Au is zero, and does not determine “v> V” when the lateral acceleration Av is zero.

  Next, when both the determination based on the acceleration Au and the determination based on the lateral acceleration Av are performed in the water level determination step S2, the control device 5 of the exhaust / drain valve 31 only satisfies both of these determination formulas. Only the water is discharged from the water storage container 40 while allowing the opening (valve opening step: S3a). On the other hand, if any one of the determination formulas is not satisfied, the control device 5 prohibits the exhaust / drain valve 31 from being opened (valve closing step: S3b). Note that when the acceleration Au is zero, the control device 5 performs only the determination based on the lateral acceleration Av. Therefore, if this determination formula is satisfied, the exhaust / drain valve 31 is allowed to open (valve opening step: S3a). If not satisfied, opening of the exhaust / drain valve 31 is prohibited (valve closing step: S3b). Similarly, when the lateral acceleration Av is zero, only the determination based on the acceleration Au is performed. Therefore, if the determination formula is satisfied, the exhaust / drain valve 31 is allowed to open (valve opening step: S3a) and must be satisfied. For example, the opening of the exhaust / drain valve 31 is prohibited (valve closing step: S3b). The valve opening step S3a and the valve closing step S3b constitute an embodiment of the valve control step in the present invention.

  In the fuel cell system 1 according to the embodiment described above, when water is moving in the water storage container 40 due to the generation of inertia force based on the acceleration, the acceleration sensor 6 detects the acceleration, and the water is detected based on this. It is determined whether or not it is in a position where it can be discharged from the drain port 41, and opening / closing control of the exhaust drain valve 31 is performed according to the result. Specifically, it is determined whether or not the discharge port 41 is hidden under the water surface. When the discharge port 41 is not hidden under the water surface, the opening of the exhaust / drain valve 31 is prohibited. Thereby, mixing of gas into the waste water can be suppressed, and unintended gas discharge can be suppressed in the purge operation. Accordingly, the fuel consumption rate of the fuel cell vehicle S can be improved, the drainage control error can be reduced, and the target amount of drainage can be discharged.

  Further, in the fuel cell system 1 according to the embodiment described above, since the drainage port 41 is provided on the side surface of the water storage container 40, the exhaust drainage flow path 25, which is the water discharge path from the water storage container 40, and the exhaust gas The drain valve 31 can be arranged on the side of the water storage container 40 instead of below it. Therefore, the height of the mounting space for the water storage container 40 and the exhaust / drain valve 31 can be reduced, and the response to the lower floor of the fuel cell vehicle S can be facilitated.

  In the fuel cell system 1 according to the embodiment described above, the determination is made based on both the linear acceleration generated in the fuel cell vehicle S and the acceleration in the centrifugal force direction. Even when performing a combined exercise of exercise, it is possible to determine whether or not water can be discharged with a simple determination formula.

  Although the exhaust drain valve control when the fuel cell vehicle S is accelerated has been described in the above embodiment, the same exhaust drain valve control can be performed even when the fuel cell vehicle S is decelerated.

  In the above embodiment, the drain outlet 41 is provided at the lower end of the side surface on the right side of the vehicle, and the exhaust drain valve control when the fuel cell vehicle S is turned to the right has been described. The same exhaust drain valve control can be performed even when the fuel cell vehicle S is turned to the left by being provided at the lower end.

  Moreover, in the above embodiment, although the bottom face of the water storage container 40 was made horizontal, the shape of the water storage container 40 can be variously modified. For example, it may be a circular or elliptical bottom surface or a polygonal bottom surface instead of a rectangular bottom surface. Further, a step or an inclination may be provided on the bottom surface. Thus, even if the shape of the water storage container is variously changed, it is possible to perform the same determination by appropriately setting a determination formula for determining whether or not the discharge port is hidden under the water surface. . Therefore, the mixing of gas into the waste water can be suppressed as in the above embodiment.

  Moreover, in the above embodiment, the configuration in which the exhaust / drain valve 31 that integrally performs exhaust and drainage is provided downstream of the gas-liquid separator 30 is adopted, but the water collected by the gas-liquid separator 30 is discharged to the outside. The drain valve for exhausting and the exhaust valve for discharging the gas in the circulation channel 23 to the outside are separately provided, and the drain valve and the exhaust valve are separately controlled by the control device 5, and the above-described control is performed for the drain valve. Form control can be applied. Even in such a case, the mixing of the gas into the waste water is suppressed as in the above embodiment, so that the drainage control error can be reduced and the unintended discharge of the gas can be suppressed.

  In the above embodiment, an example in which the fuel cell system according to the present invention is mounted on a fuel cell vehicle has been described. The fuel cell system according to the invention can also be mounted. Further, the fuel cell system according to the present invention may be applied to a stationary power generation system used as a power generation facility for buildings (for example, houses, buildings, factories, etc.).

1 is a conceptual diagram of a fuel cell vehicle equipped with a fuel cell system according to an embodiment of the present invention. 1 is a configuration diagram of a fuel cell system according to an embodiment of the present invention. FIG. 3 shows a water storage container provided in the gas-liquid separator of the fuel cell system shown in FIG. 2, (A) is a cross-sectional view in the vehicle longitudinal direction, and (B) is a cross-sectional view in the vehicle width direction. FIG. 2 is a cross-sectional view showing the state of water in a water storage container when the fuel cell vehicle shown in FIG. 1 is running straight. FIG. 2 is a cross-sectional view showing a state of water in a water storage container when the fuel cell vehicle shown in FIG. 1 is turning. It is a flowchart which shows the control method of the exhaust drain valve which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 2 ... Fuel cell, 5 ... Control apparatus (control means, water amount estimation means), 6 ... Acceleration sensor (acceleration detection means), 30 ... Gas-liquid separator, 31 ... Exhaust drain valve (discharge valve) , 40 ... Water storage container (water storage part), 41 ... Drainage port, Au ... Acceleration (acceleration in the linear direction), Av ... Lateral acceleration (acceleration in the centrifugal force direction), S ... Fuel cell vehicle (moving body).

Claims (12)

A fuel cell; a water storage section for storing water discharged from the fuel cell; a discharge valve disposed downstream of a drain outlet provided in the water storage section; and a control means for controlling the discharge valve. In the fuel cell system provided,
Acceleration detecting means for detecting the acceleration of the water reservoir,
The control means determines whether or not the water in the water reservoir is in a position where it can be discharged from the drain outlet based on the acceleration of the water reservoir detected by the acceleration detector, and the result of the determination Based on the control of the opening and closing of the discharge valve,
Fuel cell system. The control means determines whether or not the discharge port is hidden under the water surface based on the acceleration of the water storage section, and allows the discharge valve to be opened when the discharge port is hidden under the water surface. And, when the discharge port is not hidden under the water surface, the opening of the discharge valve is prohibited.
The fuel cell system according to claim 1. The discharge port is provided on a side surface of the water storage unit.
The fuel cell system according to claim 1 or 2. The water storage section is a water storage container provided in a gas-liquid separator that separates water from a fuel off gas discharged from the fuel cell.
The fuel cell system according to any one of claims 1 to 3. The discharge valve is an exhaust / drain valve that discharges water and fuel off-gas in the reservoir.
The fuel cell system according to any one of claims 1 to 4. A fuel cell system mounted on a moving body,
The acceleration detection means detects an acceleration of the water storage section that is generated along with a linear motion and / or a turning motion of the moving body.
The fuel cell system according to any one of claims 1 to 5. The acceleration detection means detects linear acceleration generated along with the linear motion of the moving body,
The control means determines whether or not the water in the reservoir is in a position where the water can be discharged from the drain outlet based on the acceleration in the linear direction, and opens and closes the discharge valve based on the determination result. Which controls
The fuel cell system according to claim 6. The acceleration detecting means detects an acceleration in a centrifugal force direction generated with a turning motion of the moving body,
The control means determines whether or not the water in the reservoir is in a position where it can be discharged from the drain outlet based on the acceleration in the centrifugal force direction, and based on the result of the determination, Which controls opening and closing,
The fuel cell system according to claim 6. The acceleration detection means detects acceleration in a linear direction and a centrifugal force direction generated along with a linear motion and a turning motion of the moving body,
The control means determines whether or not the water in the water reservoir is in a position where the water can be discharged from the drainage port based on the acceleration in the linear direction and the centrifugal force direction, and based on the determination result, Which controls the opening and closing of the discharge valve,
The fuel cell system according to claim 6. Water amount estimating means for estimating the amount of water stored in the water reservoir based on the amount of power generated by the fuel cell;
The control means is in a position where water in the water storage section can be discharged from the drain outlet based on the acceleration of the water storage section detected by the acceleration detection means and the water amount estimated by the water amount estimation means. And determining whether or not to open and close the discharge valve based on the result of the determination,
The fuel cell system according to any one of claims 1 to 9. A method for controlling a discharge valve in a fuel cell system, comprising: a fuel cell; a water storage unit that stores water discharged from the fuel cell; and a discharge valve disposed downstream of a drain port provided in the water storage unit. Because
An acceleration detection step of detecting an acceleration of the water reservoir;
Based on the acceleration detected in the acceleration detection step, a water level determination step for determining whether or not the water in the water reservoir is in a position where it can be discharged from the drain port;
A valve control step of controlling the opening and closing of the discharge valve based on the determination result in the water level determination step,
Control method of discharge valve. A control method of a discharge valve in a fuel cell system mounted on a moving body,
In the acceleration detection step, the acceleration of the water storage section that occurs with the linear motion and / or the turning motion of the moving body is detected.
The method for controlling the discharge valve according to claim 10.

Images