JP2006147161A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system controlling the switching of a drain valve in appropriate timing and at an appropriate time. <P>SOLUTION: The fuel cell system 1 is composed of a fuel cell 2, a gas-liquid separator 3 separating moisture from anode gas, a drain valve 4 opening and closing a drain port of separated water, a temperature sensor 5 measuring the temperature of anode gas, a current sensor 6 measuring a current value generated by the fuel cell, an ECU 7 controlling the switching of the drain valve 4, a hydrogen tank 11 storing hydrogen, an ejector 12, a compressor 13 and an anode gas flow channel and a cathode gas flow channel combining these, and a driving device 14 driven at a current supplied from the fuel cell 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell system, and more particularly to a control system for a gas-liquid separator in a fuel cell system.

The fuel cell includes an anode electrode and a cathode electrode with an electrolyte membrane interposed therebetween. When an anode gas (fuel gas) containing hydrogen is supplied to the anode electrode, a reaction occurs in the catalyst layer of the anode electrode, and the hydrogen in the anode gas is divided into protons (H ⁺ ) and electrons, and the protons are in the electrolyte membrane. The electrons move through the external circuit to the cathode electrode. When cathode gas (oxidant gas) containing oxygen is supplied to the cathode electrode, a reaction occurs in the catalyst layer of the cathode electrode, and oxygen in the cathode gas reacts with protons and electrons that have moved from the anode electrode. Water is generated. At this time, water generated at the cathode electrode may permeate the electrolyte membrane and move to the anode electrode side due to the water vapor pressure difference between the anode electrode and the cathode electrode. If the anode gas contains extra droplets, the power generation efficiency deteriorates. Therefore, a gas-liquid separator is installed in the anode gas flow path to remove the extra droplets.

As a conventional gas-liquid separator, for example, as described in Patent Document 1, there is one including a water recovery tank and a water level sensor for detecting the water level in the tank. When the water level sensor detects that the water level in the water recovery tank has reached a predetermined level, the control device opens the drain valve of the water recovery tank to discharge water.
The anode gas from which the droplets have been removed (anode off gas) is circulated through the anode gas supply path and reused.
JP 2002-124290 A (paragraphs 0036 to 0040, FIG. 2)

  However, in the conventional fuel cell system described in Patent Document 1, when mounted on a moving object such as an automobile, the water level sensor is affected by, for example, an inclined land, and the amount of water in the water recovery tank is reduced. There is a risk of false detection. That is, when the water level sensor detects a larger amount of water than it actually is, there is a problem that the anode gas is excessively discharged, resulting in deterioration of fuel consumption.

  On the other hand, if the fuel cell system continues to operate, impurities (for example, droplets) in the anode gas increase, the amount of hydrogen decreases relatively, and power generation efficiency may also deteriorate. In such a case, it is necessary to purge and refresh the anode gas. At this time, it is conceivable to purge the anode gas using the drain valve of the water recovery tank. However, in the conventional control system, it is not possible to perform control in consideration of the purge amount of the anode gas. There is a problem in that it may be discharged excessively, resulting in deterioration of fuel consumption.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a fuel cell system that controls opening and closing of a drain valve at an appropriate timing and time.

  A fuel cell system according to claim 1 of the present invention is installed on a fuel cell having an anode and a cathode with an electrolyte interposed therebetween, and a flow path of an anode gas discharged from the anode, A gas-liquid separator that separates water contained therein, a drain valve that opens and closes a discharge port for discharging water collected by the gas-liquid separator, a temperature sensor that measures an anode gas temperature, and a generated current in the fuel cell A fuel cell system comprising: a current sensor for measuring a value; and a control means for controlling opening and closing of the drain valve, wherein the control means is based on the anode gas temperature and the generated current value. Calculating a drain valve opening time corresponding to a water discharge amount determined from the amount of water recovered by the gas-liquid separator, and opening and closing the drain valve based on the drain valve opening time. And butterflies.

  According to this configuration, the fuel cell system has a drain valve opening time corresponding to a water discharge amount determined from the amount of water recovered by the gas-liquid separator based on the anode gas temperature and the generated current value. Since the control means for opening and closing the drain valve based on the drain valve opening time is provided, the drain valve opening and closing time can be determined by calculating the water discharge amount. Therefore, it is possible to prevent erroneous detection of the water discharge amount due to the inclination of the fuel cell system.

  A fuel cell system according to a second aspect of the present invention is the fuel cell system according to the first aspect, wherein the control means includes a correlation stored in advance between a generated current value, an anode gas temperature, and the amount of condensed water. The condensed water amount calculating means for calculating the amount of condensed water per unit time based on the anode gas temperature and the generated current value, and the gas-liquid separator collects the condensed water amount based on the amount of condensed water per unit time. Based on the water discharge calculating means for calculating the water discharge determined from the amount of water, the correlation stored in advance between the water discharge and the drain valve opening time corresponding to the water discharge, and the water discharge First drain valve opening time calculating means for calculating a drain valve opening time corresponding to the water discharge amount, and a drain valve for controlling opening and closing of the drain valve based on the drain valve opening time corresponding to the water discharge amount Opening and closing system Characterized in that it comprises a means.

  According to such a configuration, the fuel cell system calculates the water discharge amount and the drain valve opening time based on the anode gas temperature, the generated current value, and some correlation data stored in advance, and based on this The opening and closing of the drain valve can be controlled.

A fuel cell system according to a third aspect of the present invention is the fuel cell system according to the first or second aspect, wherein the control means further controls the anode gas temperature and the required H ₂ emission amount. Based on the drain valve opening time corresponding to the anode gas discharge amount and the drain valve opening time corresponding to the anode gas discharge amount. It is characterized by opening and closing.

According to this configuration, the control unit further calculates a drain valve opening time corresponding to the anode gas discharge amount based on the anode gas temperature and the required H ₂ discharge amount, and corresponds to the water discharge amount. Since the drain valve is opened and closed based on the drain valve opening time and the drain valve opening time corresponding to the anode gas discharge amount, the anode gas is also purged when the water collected by the gas-liquid separator is discharged. , The drain valve can be opened and closed by managing the amount of H ₂ contained in the discharged anode gas. Therefore, it is possible to prevent wasteful emission of H _2.

Here, the required H ₂ emission amount is the amount of H ₂ to be contained in the anode gas discharged at a time. When the temperature of the anode gas is lowered, the saturated water vapor amount of the anode gas is reduced, and the amount of H ₂ contained in the anode gas is relatively increased. Conversely, when the temperature of the anode gas increases, the saturated water vapor amount of the anode gas increases, and the amount of H ₂ contained in the anode gas relatively decreases.

A fuel cell system according to a fourth aspect of the present invention is the fuel cell system according to the second aspect, wherein the control means opens the drain corresponding to the anode gas temperature, the required H ₂ emission amount, and the anode gas emission amount. Second drain valve opening time calculation means for calculating a drain valve opening time corresponding to the anode gas discharge amount based on the correlation stored in advance with the valve time, the anode gas temperature, and the required H ₂ discharge amount. The drain valve opening / closing control means controls the opening / closing of the drain valve based on a drain valve opening time corresponding to the anode gas discharge amount and a drain valve opening time corresponding to the water discharge amount. Features.

According to this configuration, the second drain valve opening time calculating means stores the correlation stored in advance between the anode gas temperature, the required H ₂ discharge amount, and the drain valve opening time corresponding to the anode gas discharge amount, and the anode gas temperature. Since the drain valve opening time corresponding to the anode gas discharge amount can be calculated based on the required H ₂ discharge amount, the anode gas is also purged when the water collected by the gas-liquid separator is discharged. In some cases, the drain valve can be opened and closed by managing the amount of H ₂ contained in the discharged anode gas. Thus, it is possible to prevent wasteful emission of H _2.

  A fuel cell system according to claim 5 of the present invention is installed on a fuel cell having an anode electrode and a cathode electrode with an electrolyte interposed therebetween, and a flow path of an anode gas discharged from the anode electrode. A gas-liquid separator that separates water contained therein, a drain valve that opens and closes a discharge port for discharging water collected by the gas-liquid separator, a first temperature sensor that measures an anode gas temperature, and a cathode gas temperature A fuel cell system comprising a second temperature sensor to measure and a control means for controlling opening and closing of the drain valve, wherein the control means is based on the anode gas temperature and the cathode gas temperature, The drain valve opening time corresponding to the water discharge amount determined from the amount of water recovered by the gas-liquid separator is calculated, and the drain valve opening time corresponding to the water discharge amount is calculated. Characterized by opening and closing the.

  According to this configuration, in the fuel cell system, the control unit corresponds to a water discharge amount determined from the amount of water recovered by the gas-liquid separator based on the anode gas temperature and the cathode gas temperature. And a control means for opening and closing the drain valve based on the drain valve opening time corresponding to the water discharge amount. Therefore, the drain valve opening and closing time is obtained by calculating the water discharge amount. Can be determined. Therefore, it is possible to prevent erroneous detection of the water discharge amount due to the inclination of the fuel cell system.

  A fuel cell system according to a sixth aspect of the present invention is the fuel cell system according to the fifth aspect, wherein the control means is configured to generate a cathode gas and an anode based on the anode gas temperature and the cathode gas temperature. Based on the water vapor partial pressure difference calculating means for calculating the water vapor partial pressure difference of the gas, the pre-stored correlation between the water vapor partial pressure difference and the amount of condensed water per unit time at the anode electrode, and the water vapor partial pressure difference at the anode electrode Condensed water amount calculating means for calculating the amount of condensed water per unit time, and water discharge amount calculating means for calculating a water discharge amount determined from the amount of water collected by the gas-liquid separator based on the condensed water amount per unit time And a drain opening time corresponding to the water discharge amount based on a pre-stored correlation between the water discharge amount and the drain valve opening time and the water discharge amount. A first drain opening time calculation means, characterized in that it comprises a drain valve opening and closing control means for controlling the opening and closing of the drain valve based on the drain valve open time corresponding to the water discharge amount.

  According to this configuration, the water discharge amount and the drain valve opening time are calculated based on the anode gas temperature, the cathode gas temperature or the cathode gas humidity, and some correlation data stored in advance. Thus, the opening and closing of the drain valve can be controlled. Therefore, it is possible to prevent erroneous detection of the water discharge amount due to the inclination of the fuel cell system.

A fuel cell system according to claim 7 of the present invention is the fuel cell system according to claim 6, wherein the fuel cell system further includes a pressure sensor for measuring an anode gas pressure, and the control means includes the control unit Based on the anode gas temperature, the anode gas pressure, and the required H ₂ discharge amount, a drain valve opening time corresponding to the anode gas discharge amount is calculated, and the drain valve opening time corresponding to the water discharge amount and the anode The drain valve is opened and closed based on the drain valve opening time corresponding to the gas discharge amount.

According to this configuration, the control means calculates the drain valve opening time corresponding to the anode gas discharge amount based on the anode gas temperature, the anode gas pressure, and the required H ₂ discharge amount, and the water discharge Since the drain valve is opened and closed based on the drain valve opening time corresponding to the amount and the drain valve opening time corresponding to the anode gas discharge amount, the anode gas is discharged when the water collected by the gas-liquid separator is discharged. In the case of purging, the drain valve can be opened and closed by managing the amount of H ₂ contained in the discharged anode gas. Therefore, it is possible to prevent wasteful emission of H _2.

A fuel cell system according to an eighth aspect of the present invention is the fuel cell system according to the seventh aspect, wherein the control means adjusts the anode gas temperature, the anode gas pressure, and the required H ₂ emission amount. Based on the anode gas discharge amount setting means for setting the anode gas discharge amount based on the correlation stored in advance between the anode gas discharge amount and the drain valve opening time, and the anode gas discharge amount Second drain valve opening time calculating means for calculating a drain valve opening time corresponding to the amount, wherein the drain valve opening / closing control means comprises a drain valve opening time corresponding to the anode gas discharge amount and the water discharge amount. The opening and closing of the drain valve is controlled based on the drain valve opening time corresponding to.

According to this configuration, the anode gas discharge amount setting means sets the anode gas discharge amount based on the anode gas temperature, the anode gas pressure, and the required H ₂ discharge amount, and calculates the second drain valve opening time. The means calculates the drain valve opening time corresponding to the anode gas discharge amount based on the correlation stored in advance between the anode gas discharge amount and the drain valve opening time and the anode gas discharge amount, and the drain Since the opening / closing control means controls the opening / closing of the drain valve based on the drain opening time corresponding to the anode gas discharge amount and the drain opening time corresponding to the water discharge amount, the gas-liquid separator In the case where the anode gas is purged when the water recovered in step 1 is discharged, the amount of H ₂ contained in the discharged anode gas is controlled to The in-valve can be opened and closed. Therefore, it is possible to prevent wasteful emission of H _2.

A fuel cell system according to a ninth aspect of the present invention is the fuel cell system according to the eighth aspect, wherein the anode gas discharge amount setting means calculates a water vapor partial pressure in the anode gas based on the anode gas temperature. A water vapor partial pressure calculating means for calculating, a pressure ratio calculating means for calculating a pressure ratio between the total pressure of the anode gas and the partial pressure of hydrogen based on the anode gas pressure and the water vapor partial pressure; Based on the pressure ratio between the total pressure and the partial pressure of hydrogen, the required H ₂ discharge amount at a predetermined temperature and a predetermined pressure, the anode gas pressure, and the anode gas temperature, the anode gas at the time of discharging the anode gas And an anode gas discharge amount calculating means for calculating an anode gas discharge amount corresponding to the pressure and temperature.

According to this configuration, the partial pressure of water vapor in the anode gas is calculated based on the anode gas temperature by the water vapor partial pressure calculation means, and the anode gas pressure and the water vapor partial pressure are calculated by the pressure ratio calculation means. The pressure ratio between the total pressure of the anode gas and the partial pressure of hydrogen is calculated based on the pressure ratio between the total pressure of the anode gas and the partial pressure of hydrogen, and a predetermined temperature / predetermined pressure. Based on the required H ₂ emission amount below, the anode gas pressure, and the anode gas temperature, an anode gas emission amount corresponding to the pressure and temperature of the anode gas at the time of anode gas emission is calculated. According to the anode gas corresponding to the anode gas emissions, since it contains the H ₂ corresponding to the required H ₂ emissions, if the switching control of the drain valve on the basis of the anode gas emissions of H ₂ Wasteful release can be prevented.

  The fuel cell system according to claim 10 is the fuel cell system according to any one of claims 6 to 9, wherein the first humidity sensor and / or the cathode gas humidity for measuring the anode gas humidity is measured. The water vapor partial pressure difference calculating means further includes a second humidity sensor for measuring, and the means for calculating the water vapor partial pressure difference is based on the anode gas temperature, the cathode gas temperature, the anode gas humidity and / or the cathode gas humidity, A difference in water vapor partial pressure at the anode electrode is calculated.

  According to this configuration, the difference in water vapor partial pressure between the cathode electrode and the anode electrode is calculated by the water vapor partial pressure difference calculating means based on the anode gas temperature, the cathode gas temperature, the anode gas humidity and / or the cathode gas humidity. Therefore, it is possible to prevent erroneous detection of water discharge due to the inclination of the fuel cell system. In addition, since accurate anode gas humidity and / or cathode gas humidity can be measured by the first humidity sensor and / or the second humidity sensor, the anode electrode and / Alternatively, the water vapor partial pressure at the cathode electrode can be grasped more accurately, and the calculation accuracy of the water discharge amount can be further improved.

  According to the fuel cell system according to claim 1 and claim 2 of the present invention, the amount of water discharged from the gas-liquid separator can be grasped based on the anode gas temperature and the generated current value. Unaffected by changes in battery system attitude. Therefore, even when the attitude of the fuel cell system changes, the opening and closing of the drain valve can be controlled at an appropriate timing and time without erroneously detecting the water discharge amount.

According to the fuel cell system of claims 3 and 4 of the present invention, the drain valve opening time corresponding to the anode gas discharge amount is calculated based on the anode gas temperature and the required H ₂ discharge amount. Therefore, when the anode gas is also purged when the water collected by the gas-liquid separator is discharged, the drain valve can be opened and closed by managing the amount of H ₂ contained in the discharged anode gas. For this reason, H ₂ is not discharged unnecessarily, and fuel consumption can be improved.

  Furthermore, according to the fuel cell system according to claims 5, 6 and 10 of the present invention, the fuel cell system is configured to output from the gas-liquid separator based on the anode gas temperature or anode gas humidity and the cathode gas temperature or cathode gas humidity. Since the water discharge amount can be grasped, it is not affected by the change in the attitude of the fuel cell system. Therefore, even when the attitude of the fuel cell system changes, the opening and closing of the drain valve can be controlled at an appropriate timing and time without erroneously detecting the water discharge amount.

Further, according to the fuel cell system according to claims 7 to 9 of the present invention, the required H ₂ emission amount is accommodated based on the anode gas temperature, the anode gas pressure, and the required H ₂ emission amount. Since the anode gas discharge amount can be calculated, when the anode gas is purged when the water collected by the gas-liquid separator is discharged, the drain valve is controlled by managing the amount of H ₂ contained in the discharged anode gas. Can be opened and closed. For this reason, H ₂ is not discharged unnecessarily, and fuel consumption can be improved.

  The best mode for carrying out the present invention will be described in detail with reference to the drawings. In the description, the same elements are denoted by the same reference numerals, and redundant description is omitted.

<First Embodiment>
As a first embodiment, a case will be described in which the present invention is applied to a fuel cell system that controls the open / close time of a drain valve based on the value of a generated current generated by a fuel cell and the temperature of an anode gas.

(Configuration of fuel cell system 1)
FIG. 1 is a schematic configuration diagram showing a fuel cell system according to a first embodiment of the present invention.
As shown in FIG. 1, the fuel cell system 1 includes a fuel cell 2, a gas-liquid separator 3 that separates moisture from the anode gas, a drain valve 4 that opens and closes the outlet of the separated water, and an anode gas A temperature sensor 5 for measuring temperature, a current sensor 6 for measuring a current value generated by the fuel cell, an ECU 7 for controlling the opening and closing of the drain valve 4, a hydrogen tank 11 for storing hydrogen, an ejector 12, and a compressor 13, an anode gas channel and a cathode gas channel connecting these, and a driving device 14 driven by a current supplied from the fuel cell 2. The fuel cell system 1 discharges the water separated and collected by the gas-liquid separator 3 from the drain valve 4 and discharges the anode gas from the drain valve 4.
Hereinafter, each component of the fuel cell system 1 will be described.

(Fuel cell 2)
As shown in FIG. 1, the fuel cell 2 includes an anode electrode 22 and a cathode electrode 23 with an electrolyte membrane 21 interposed therebetween. The anode electrode 22 is connected to the hydrogen tank 11 via pipes 11a and 12a, and is supplied with an anode gas (fuel gas) containing hydrogen. Moreover, the anode electrode 22 is connected to the gas-liquid separator 3 via the pipe 5a. The cathode electrode 23 is connected to the compressor 13 via a pipe 13a, and is supplied with a cathode gas containing oxygen (oxidant gas, for example, air). Moreover, the cathode electrode 23 can discharge | release cathode gas and produced | generated water through the piping 13b.

When the anode gas is supplied to the anode electrode 22, a reaction occurs in the catalyst layer of the anode electrode 22, hydrogen in the anode gas is divided into protons (H ⁺ ) and electrons, and the protons pass through the electrolyte membrane 21 and are cathodes. The electrons move to the electrode 23, and the electrons move to the cathode electrode 23 through the external circuits 6a and 6b. When the cathode gas is supplied to the cathode electrode 23, a reaction occurs in the catalyst layer of the cathode electrode, and water in the cathode gas reacts with protons and electrons that have moved from the anode electrode. The external circuits 6 a and 6 b are connected to a drive device 14, and the drive device 14 is driven by receiving a current supplied from the fuel cell 2.

(Gas-liquid separator 3)
The gas-liquid separator 3 is a device that separates moisture from the anode gas discharged from the fuel cell 2, and is connected to the anode electrode 22 of the fuel cell 2 via a pipe 5a as shown in FIG. The gas-liquid separator 3 includes a tank that stores water separated from the anode gas. The gas-liquid separator 3 is connected to the ejector 12 via a pipe 3a, and the anode gas separated from the water by the gas-liquid separator 3 is sucked up by the ejector 12 and supplied to the fuel cell 2 again. The Furthermore, the gas-liquid separator 3 is provided with a pipe 3b serving as a drain port, so that the collected water can be discharged.

(Drain valve 4)
As shown in FIG. 1, the drain valve 4 is provided in the middle of a pipe 3 b that is a drain port of the gas-liquid separator 3, and can open and close the pipe 3 b. The drain valve 4 is electrically connected to an ECU 7 which will be described later, and opens and closes in response to a signal from the ECU 7. As the drain valve 4, for example, a ball-type or butterfly-type motor-operated valve can be used.

(Temperature sensor 5)
The temperature sensor 5 is a sensor that measures the temperature of the anode gas discharged from the anode electrode 22, and as shown in FIG. 1, is installed in a pipe 5a that is a flow path of the anode gas. Further, the temperature sensor 5 is connected to an ECU 7 which will be described later, and the measured temperature data of the anode gas can be transmitted to the ECU 7.

(Current sensor 6)
The current sensor 6 is a sensor that measures a current value (generated current value) generated by the fuel cell 2 and is provided on an external circuit 6a that connects the fuel cell 2 and the driving device 14 as shown in FIG. It has been. Further, the current sensor 6 is connected to an ECU 7 which will be described later, and the measured generated current value can be transmitted to the ECU 7.

(ECU 7)
FIG. 2 is a block diagram showing a configuration of the ECU.
The ECU 7 is a so-called electronic control unit (Electrical Control Unit), and includes a control means 8 and a data storage means 9 as shown in FIGS. The ECU 7 is connected to the temperature sensor 5 and the current sensor 6 and calculates the valve opening time (drain valve opening time) of the drain valve 4 based on the anode gas temperature and the generated current value sent from each sensor. It is like that. The ECU 7 is connected to the drain valve 4 and transmits a control signal corresponding to the drain valve opening time to the drain valve 4.
Hereinafter, the configuration of the control means 8 and the data storage means 9 will be described in detail with reference to FIG.

(Control means 8)
The control means 8 is constituted by, for example, a central processing unit, a storage device, and the like. As shown in FIG. 2, the condensed water amount calculation means 81, the water discharge amount calculation means 82, and the first drain valve opening time calculation means 83, The required H2 emission amount calculating means 84, the second drain valve opening time calculating means 85, and the drain valve opening / closing control means 86 are included.

(Condensation water amount calculation means 81)
The condensed water amount calculation means 81 plays a role of calculating the amount of condensed water that forms condensation on the anode electrode 22 of the fuel cell 2. Specifically, the condensed water amount calculating means 81 is based on the anode gas temperature data and the generated current value data received from the temperature sensor 5 and the current sensor 6, and the generated current value stored in advance in the correlation data storage means described later. The amount of condensed water x _n per unit time is calculated with reference to correlation data A corresponding to the correlation between the anode gas temperature and the amount of condensed water (see FIG. 4A). The condensed water amount calculation means 81 stores the calculated condensed water amount x _n per unit time in the condensed water amount storage means 91 described later while associating it with the measurement time t _n (see FIG. 4B). .
The correlation between the generated current value, the anode gas temperature, and the amount of condensed water will be described in detail later.

(Water discharge calculation means 82)
The water discharge amount calculating means 82 plays a role of calculating a water drainage amount Σx determined from the amount of water stored in the gas-liquid separator 3. Specifically, the water discharge amount calculation unit 82 reads out the condensed water amount per unit time stored in the condensed water amount storage unit 91 and sums them when, for example, a predetermined time has elapsed since the previous water discharge time. Thus, the amount of water drainage Σx is calculated. Further, the water discharge amount calculating means 82 transmits data about the calculated water drainage amount Σx to the first drain valve opening time calculating means 83.

(First drain valve opening time calculation means 83)
The first drain valve opening time calculating means 83 calculates a drain valve opening time T ₁ corresponding to the water drainage amount Σx (hereinafter sometimes simply referred to as “drain valve opening time T ₁ ”) based on the water drainage amount Σx. To play a role. Specifically, the first drain valve opening time calculation means 83 is configured to calculate the water discharge amount and the water stored in advance in the correlation data storage means 92 described later based on the water discharge amount Σx received from the water discharge amount calculation means 82. The drain valve opening time T ₁ corresponding to the water discharge amount is calculated with reference to the correlation data B corresponding to the correlation (see FIG. 4C) with the drain valve opening time corresponding to the discharge amount. ing. Further, the first drain valve opening time calculation means 83 transmits the drain valve opening time T ₁ corresponding to the calculated water discharge amount to the drain valve opening / closing control means 86.

(Required H ₂ emission calculation means 84)
The required H ₂ emission amount calculation means 84 plays a role of calculating the required H ₂ emission amount based on the generated current value. Specifically, the required H ₂ emission amount calculation means 84 reads the generated current value at that time from the current sensor when, for example, a predetermined time has elapsed since the end of the previous emission, and stores it in the correlation data storage means 92 described later in advance. The required H ₂ emission amount is calculated with reference to correlation data C corresponding to the correlation between the generated power generation value and the required H ₂ emission amount (see FIG. 5A). Further, the required H ₂ emission amount calculation means 84 transmits data on the calculated required H ₂ emission amount to the second drain valve opening time calculation means 85.
In the first embodiment, it is assumed that seek request H ₂ emissions from the correlation between the generated current value and the required H ₂ emissions required H ₂ emissions may be a fixed value.

(Second drain valve opening time calculating means 85)
The second drain valve opening time calculation means 85 is a drain valve opening time T ₂ (hereinafter simply referred to as “drain valve opening time T ₂ ”) corresponding to the anode gas discharge amount based on the required H ₂ discharge amount and the anode gas temperature. In some cases). Specifically, the second drain valve opening time calculating means 85 will be described later based on the requested H ₂ emission amount received from the requested H ₂ emission amount calculating means 84 and the anode gas temperature received from the temperature sensor 5. Correlation data D corresponding to the correlation (see FIG. 5B) of the required H ₂ discharge amount, the anode gas temperature, and the drain valve opening time corresponding to the anode gas discharge amount stored in advance in the correlation data storage means 92 is obtained. Referring to, the drain valve opening time T ₂ corresponding to the anode gas discharge amount is calculated. Further, the second drain valve opening time calculating means 85 transmits the calculated drain valve opening time T ₂ to the drain valve opening / closing control means 86.

(Drain valve opening / closing control means 86)
The drain valve opening / closing control means 86 plays a role of controlling the opening / closing of the drain valve 4 based on the drain valve opening time T ₁ corresponding to the water discharge amount and the drain valve opening time T ₂ corresponding to the anode gas discharge amount. It is. Specifically, when the drain valve opening / closing control means 86 receives the drain valve opening time T ₁ corresponding to the water discharge amount and the drain valve opening time T ₂ corresponding to the anode gas discharge amount, the drain valve opening / closing control means 86 adds these times. A control signal corresponding to the total time is generated and transmitted to the drain valve 4.

(Data storage means 9)
The data storage means 9 is composed of, for example, a memory device, and includes a condensed water amount storage means 91 and a correlation data storage means 92 as shown in FIGS. The data storage means 9 is connected to the control means 8 and can read and write data.

(Condensate amount storage means 91)
The condensed water amount storage unit 91 plays a role of storing the condensed water amount x _n per unit time in the anode electrode 22 calculated by the condensed water amount calculation unit 81. For example, the condensed water amount x _n per unit time is stored in a database in association with the measurement time t _n of the generated current value, as shown in FIG. 4B.

(Correlation data storage means 92)
The correlation data storage unit 92 plays a role of storing various correlations necessary for calculating the drain valve opening time based on the anode gas temperature and the generated current value as data. The correlation data storage unit 92 includes (A) a correlation between the generated current value, the anode gas temperature, and the amount of condensed water, and (B) a correlation between the water discharge amount and the drain valve opening time corresponding to the water discharge amount, (C) Corresponds to the correlation between the generated current value and the required H ₂ emission amount, and (D) the correlation between the required H ₂ emission amount, the anode gas temperature, and the drain valve opening time corresponding to the anode gas emission amount. 4 correlation data A, B, C, and D are stored. Hereinafter, these correlations will be described with reference to FIGS.

(A) Correlation between power generation current value, anode gas temperature, and amount of condensed water FIG. 4A is a diagram schematically showing a correlation between generated current value, anode gas temperature, and amount of condensed water. As shown in FIG. 4A, the generated current value, the anode gas temperature, and the amount of condensed water have a relationship that the amount of condensed water increases as the generated current value increases, and the amount of condensed water increases as the anode gas temperature increases. . Such a relationship is derived based on the following principle.

That is, the large generated current value means that the electrochemical reaction is active in the fuel cell 2 and the amount of water generated at the cathode electrode 23 increases. The increase in the anode gas temperature means that the cathode gas temperature also increases. For example, when the anode gas temperature _Ta and the cathode gas temperature _Tc increase at a certain rate, the water vapor content of the anode gas is increased. The pressure P _wa and the water vapor partial pressure P _wc of the cathode gas also increase at a certain rate, and as a result, the differential pressure between them (P _wc −P _wa ) also increases at a certain rate. As a result, the amount of generated water that permeates through the electrolyte membrane 21 and condenses increases.
Note that the correlation between the generated current value, the anode gas temperature, and the amount of condensed water can be obtained by experiments, for example.

(B) Correlation between water discharge amount and drain valve opening time corresponding to water discharge amount FIG. 4C schematically shows the correlation between water discharge amount and drain valve opening time corresponding to water discharge amount. FIG. The water discharge amount and the drain valve opening time corresponding to the water discharge amount have a so-called proportional relationship that the drain valve opening time becomes longer as the water discharge amount increases. The relationship can be obtained by, for example, experiments, or can be set based on the opening diameter of the piping 3b serving as the discharge port or the drain valve 4.

(C) Correlation Figure 5 and the generated current value and the required H ₂ emissions (a) is a diagram schematically showing the correlation between the generated current value and the required H ₂ emissions. As a result of research, the inventors have found that it is preferable to set the required H ₂ emission amount based on the relationship shown in FIG. That is, in the range where the generated current value is smaller than the predetermined value, the required H ₂ emission amount is set so as to be proportional to the generated current value, and in the range where the generated current value is larger than the predetermined value, safety From the point of view, it was found that it is preferable to reach the required H ₂ emission amount, and the relationship as shown in FIG. 5 was defined.

The required H ₂ emission amount may be a fixed value. In such a case, instead of the correlation between the generated current value and the required H ₂ emissions, with and stores the fixed value and the requested H ₂ emissions data storage unit 9, required H ₂ emission calculating unit 84 May be omitted, and the second drain valve opening time calculation means 85 may read out the required H ₂ discharge amount which is a fixed value, and calculate the drain valve opening time T ₂ corresponding to the anode gas discharge amount.

(D) Correlation between required H ₂ discharge amount, anode gas temperature, and drain valve opening time T ₂ FIG. 5B shows a drain valve opening corresponding to the required H ₂ discharge amount, anode gas temperature, and anode gas discharge amount. It is the figure which showed the correlation with time typically. As shown in FIG. 5B, the relationship between the required H ₂ emission amount, the anode gas temperature, and the drain valve opening time T ₂ is such that the drain valve opening time T ₂ increases (longer) as the required H ₂ emission amount increases. In addition, the higher the anode gas temperature, the longer (longer) the drain valve opening time T ₂ is. Such a relationship is derived based on the following principle.

That is, if the circulation capacity of the anode gas in the anode gas flow path is constant, the time required for discharging the anode gas (ie, the drain valve opening time T ₂ ) naturally becomes longer as the required H ₂ discharge amount increases. . Further, as the temperature of the anode gas increases, the amount of water vapor contained in the anode gas increases, and the amount of H ₂ contained in the anode gas relatively decreases. As a result, the higher the temperature of the anode gas, the longer the time required to discharge the anode gas including the required H ₂ emission amount.
From the above, the correlation as shown in FIG. 5B can be derived.

(Operation of fuel cell system 1)
Next, the operation of the fuel cell system 1 will be described with reference to FIG. 3 (refer to FIGS. 1 and 2 as appropriate). FIG. 3 is a flowchart showing an operation flow of the fuel cell system.

(Step S1)
When the previous water and anode gas discharge is completed, the dew condensation water amount calculation means 81 receives the anode gas temperature data and the generated current value data from the temperature sensor 5 and the current sensor 6, and is stored in advance in the correlation data storage means 92. The amount of condensed water _xn per unit time is calculated with reference to correlation data A corresponding to the correlation between the generated current value, the anode gas temperature, and the amount of condensed water.

The condensed water amount calculating means 81 stores the calculated condensed water amount x _n per unit time in the condensed water amount storage means 91 in association with the measurement time t _n of the anode gas temperature. Note that the condensed water amount storage unit 91 is reset, for example, when the previous discharge is completed.

(Step S2)
The water discharge amount calculation means 82 determines whether or not a predetermined time has elapsed since the previous discharge. If the predetermined time has not elapsed since the previous discharge (step S2, No), the process returns to step S1 to calculate the condensed water amount _xn per unit time and store it in the condensed water amount storage means 91.

(Step S3)
If the predetermined time has elapsed since the previous discharge (step S2, Yes), the water discharge amount calculation means 82 sums the condensed water amount _xn stored in the condensed water amount storage means 91. To calculate the water discharge amount Σx. The water discharge amount calculation means 82 transmits the calculated water discharge amount Σx to the first drain valve opening time calculation means 83.

(Step S4)
When the first drain valve opening time calculation means 83 receives data on the water discharge amount Σx from the water discharge amount calculation means 82, the drain corresponding to the water discharge amount and the water discharge amount stored in advance in the correlation data storage means 92. The drain valve opening time T ₁ corresponding to the water discharge amount is calculated with reference to the correlation data B corresponding to the correlation with the valve opening time (see FIG. 4C). The first drain valve opening time calculation means 83 transmits the calculated drain valve opening time T ₁ to the drain valve opening / closing control means 86.

(Step S5)
The request H2 emission calculating unit 84 reads a power generation current value from the current sensor, correlation between the pre-stored generated current value in the correlation data storage unit 92 and requests H ₂ emissions (FIGS. 5 (a) The required H ₂ emission amount is calculated with reference to the correlation data C corresponding to the reference). Then, the required H ₂ emission amount calculation unit 84 transmits data on the calculated required H ₂ emission amount to the second drain valve opening time calculation unit 85.

(Step S6)
When the second drain valve opening time calculation means 85 receives the required H ₂ discharge amount, the second drain valve opening time calculation means 85 reads the anode gas temperature from the temperature sensor 5 and simultaneously stores the required H ₂ discharge amount and the anode gas temperature stored in the correlation data storage means 92. The drain valve opening time T ₂ corresponding to the anode gas discharge amount is calculated by referring to the correlation data D corresponding to the correlation between the valve opening time corresponding to the anode gas discharge amount (see FIG. 5B). To do. The second drain valve opening time calculating means 85 transmits the calculated drain valve opening time T ₂ to the drain valve opening / closing control means 86.

(Step S7)
When the drain valve opening / closing control means 86 receives the drain valve opening time T ₁ corresponding to the water discharge amount and the drain valve opening time T ₂ corresponding to the anode gas discharge amount, the drain valve opening / closing control means 86 adds these times and corresponds to the total time. A control signal to be generated is transmitted to the drain valve 4. As a result, the drain valve 4 is opened for a total time of the drain valve opening time T ₁ corresponding to the water discharge amount and the drain valve opening time T ₂ corresponding to the anode gas discharge amount, and the gas-liquid separator 3 And the anode gas containing H ₂ corresponding to the required H ₂ emission amount are discharged.

  As mentioned above, although the structure and operation | movement of the fuel cell system 1 which concern on 1st Embodiment were demonstrated, this invention is not limited to the said 1st Embodiment.

  For example, in the fuel cell system 1 according to the first embodiment, the water separated by the gas-liquid separator 3 and the anode gas in the pipe are discharged from the drain valve 4. You may make it carry out by the well-known control method. The anode gas may be discharged from an anode gas purge valve (not shown), and only the water separated by the gas-liquid separator 3 may be discharged from the drain valve 4. In such a case, the required H2 emission amount calculating means 84 and the second drain valve opening time calculating means 85 can be omitted, and the correlation used by these means 84 and 85 can also be omitted.

Second Embodiment
As a second embodiment, a case will be described in which the present invention is applied to a fuel cell system 100 that controls the open / close time of a drain valve based on the temperature of the anode gas, the pressure of the anode gas, and the temperature of the cathode gas. In addition, the same number is attached | subjected to the element same as 1st Embodiment, and the overlapping description is abbreviate | omitted.

  Compared with the fuel cell system 1 according to the first embodiment, the fuel cell system 100 according to the second embodiment includes a pressure sensor 102, a second temperature sensor 103, and the current sensor 6. The points that are omitted are different from the configurations included in the control means 108 and the data storage means 109. Hereinafter, the fuel cell system 100 will be described with reference to FIGS. 6 to 9 focusing on these differences.

(Configuration of fuel cell system 100)
FIG. 6 is a schematic configuration diagram showing a fuel cell system according to a second embodiment of the present invention.
As shown in FIG. 6, the fuel cell system 100 includes a first temperature sensor 101 that measures the temperature of the anode gas and a pressure of the anode gas in a pipe 5 a that is a flow path of the anode gas discharged from the anode electrode 22. And a pressure sensor 102 for measurement. In addition, a second temperature sensor 103 that measures the temperature of the cathode gas is provided in the pipe 13 b that is a flow path of the cathode gas discharged from the cathode electrode 23.

(First temperature sensor 101)
The first temperature sensor 101 measures the temperature of the anode gas discharged from the anode electrode 22 of the fuel cell 2 at predetermined time intervals. The measured data is transmitted to the control means 108 described later.

(Pressure sensor 102)
The pressure sensor 102 measures the pressure of the anode gas discharged from the anode electrode 22 of the fuel cell 2 at predetermined time intervals. The measured data is transmitted to the control means 108 described later.

(Second temperature sensor 103)
The second temperature sensor 103 measures the temperature of the cathode gas discharged from the cathode electrode 23 of the fuel cell 2 at predetermined time intervals. The measured data is transmitted to the control means 108 described later.

(ECU 107)
FIG. 7 is a block diagram showing the configuration of the ECU.
The ECU 107 is a so-called electronic control unit (Electrical Control Unit), and includes a control means 108 and a data storage means 109 as shown in FIGS. The ECU 107 is connected to the first temperature sensor 101, the pressure sensor 102, and the second temperature sensor 103, and drains based on the anode gas temperature, anode gas pressure, and cathode gas temperature sent from each sensor. The valve opening time (drain opening time) of the valve 4 is calculated. The ECU 107 is connected to the drain valve 4 and transmits a control signal corresponding to the drain valve opening time to the drain valve 4.
Hereinafter, the configuration of the control means 108 and the data storage means 109 will be described in detail with reference to FIG.

(Control means 108)
The control means 108 is constituted by, for example, a central processing unit, and as shown in FIG. 7, the anode water vapor partial pressure calculating means 181A, the cathode water vapor partial pressure calculating means 181B, the water vapor partial pressure difference calculating means 182, and the amount of condensed water Calculation means 183, water discharge amount calculation means 184, first drain valve opening time calculation means 185, pressure ratio calculation means 186, anode gas discharge amount calculation means 187, second drain valve opening time calculation means 188, , And a drain valve opening / closing control means 189.

(Anode water vapor partial pressure calculating means 181A)
The anode water vapor partial pressure calculating means 181A plays a role of measuring the water vapor partial pressure P _wa of the anode gas discharged from the anode electrode 22. Specifically, the anode water vapor partial pressure calculating means 181A calculates the saturated water vapor pressure corresponding to the anode gas temperature based on the data related to the anode gas temperature transmitted from the first temperature sensor 101. Yes. Since the anode electrode 22 is rich in condensed water, the anode gas is considered to be saturated near the outlet of the anode electrode 22, so that “saturated water vapor pressure = water vapor partial pressure P _{wa of the} anode gas” can do. Further, the anode water vapor partial pressure calculating unit 181A transmits the calculated water vapor partial pressure P _wa of the anode gas to the water vapor partial pressure difference calculating unit 182.

また、飽和水蒸気圧は、たとえば図１０の温度Ｔ（℃）と飽和水蒸気圧Ｅ（ｈＰａ）との相関関係を示すマップ値を参照して求めてもよい。なお、温度Ｔ（℃）と飽和水蒸気圧Ｅ（ｈＰａ）との相関関係を示すマップ値は、例えば実験により求めることができる。当該マップ値は、例えば後記する相関データ記憶手段１９２に記憶される。 The saturated water vapor pressure E (hPa) at the temperature T (° C.) can be calculated using, for example, the Tetens equation shown in the following equation (1).

Further, the saturated water vapor pressure may be obtained, for example, with reference to a map value indicating the correlation between the temperature T (° C.) and the saturated water vapor pressure E (hPa) in FIG. In addition, the map value which shows correlation with temperature T (degreeC) and saturated water vapor pressure E (hPa) can be calculated | required, for example by experiment. The map value is stored in, for example, correlation data storage means 192 described later.

(Cathode water vapor partial pressure calculating means 181B)
The cathode water vapor partial pressure calculating means 181B serves to measure the water vapor partial pressure P _wc of the cathode gas discharged from the cathode electrode 23. Specifically, the cathode water vapor partial pressure calculating unit 181B calculates a saturated water vapor pressure corresponding to the cathode temperature based on data on the cathode temperature transmitted from the second temperature sensor 103. Since the cathode electrode 23 is rich in generated water, it is considered that the cathode gas is saturated near the outlet of the cathode electrode, so that “saturated water vapor pressure = water vapor partial pressure P _{wc of the} cathode gas” is set. Can do. The cathode water vapor partial pressure calculating means 181B transmits the calculated cathode gas water vapor partial pressure P _wc to the water vapor partial pressure difference calculating means 182. The calculation of the saturated water vapor pressure can be performed in the same manner as in the case of the anode gas.

(Water vapor partial pressure difference calculating means 182)
The water vapor partial pressure difference calculating means 182 calculates a partial pressure difference (water vapor partial pressure difference ΔP _w ) between the water vapor partial pressure P _wa of the anode gas and the water vapor partial pressure P _wc of the cathode gas. The water vapor partial pressure difference calculating means 182 transmits the calculated water vapor partial pressure difference ΔP _w to the condensed water amount calculating means 183. The water vapor partial pressure difference ΔP _w is calculated by the following equation (2).
ΔP _w = P _wc −P _wa (2)

(Condensation water amount calculation means 183)
The condensed water amount calculating means 183 plays a role of calculating the amount of condensed water that forms condensation on the anode electrode 22 of the fuel cell 2. Specifically, the dew condensation water amount calculating means 183 is based on the water vapor partial pressure difference ΔP _w transmitted from the water vapor partial pressure difference calculating means 182, and the water vapor partial pressure difference ΔP stored in advance in the correlation data storage means 192 described later. _By referring to correlation data E corresponding to the correlation between _w and the amount of condensed water (see FIG. 9), the amount of condensed water x _n per unit time is calculated. The condensed water amount calculation means 183 stores the calculated condensed water amount x _n per unit time in the condensed water amount storage means 191 described later while associating it with the measurement time t _n of the anode gas temperature (or cathode gas temperature). ing.

(Water discharge calculation means 184)
The water discharge amount calculation means 184 is a water drainage amount Σx determined from the amount of water stored in the gas-liquid separator 3.
It plays the role which calculates. Specifically, the water discharge amount calculating means 184 reads out the condensed water amount per unit time stored in the condensed water amount storage means 191 and sums them when, for example, a predetermined time has elapsed since the previous water discharge time. Thus, the amount of water drainage Σx is calculated. Further, the water discharge amount calculating means 184 transmits data about the calculated water drainage amount Σx to the first drain valve opening time calculating means 184.

(First drain valve opening time calculating means 185)
The first drain valve opening time calculating means 185 plays a role of calculating a time T ₁ for opening the drain valve 4 (drain opening time T ₁ corresponding to the water drainage amount Σx) based on the water drainage amount Σx. Specifically, the first drain valve opening time calculation unit 185 is configured to calculate the water discharge amount stored in advance in the correlation data storage unit 192 described later based on the water discharge amount Σx transmitted from the water discharge amount calculation unit 184. The drain valve opening time T ₁ corresponding to the water discharge amount is calculated by referring to the correlation data F corresponding to the correlation (see FIG. 4C) with the drain valve opening time corresponding to the water discharge amount. It has become. Further, the first drain valve opening time calculation means 185 transmits the calculated drain valve opening time T ₁ to the drain valve opening / closing control means 189.

(Pressure ratio calculation means 186)
The pressure ratio calculating means 186 plays a role of calculating the pressure ratio P / P _H2 between the total pressure P of the anode gas and the partial pressure P _H2 of H _{2 in} the anode gas. Specifically, the pressure ratio calculation unit 186 is based on the water vapor partial pressure P _wa of the anode gas transmitted from the anode water vapor partial pressure calculation unit and the total pressure P of the anode gas measured by the pressure sensor 102. The pressure ratio between the total pressure P of the anode gas and the partial pressure P _H2 of H _{2 in} the anode gas is calculated by the following equation (3).
P / P _H2 = P / (P−P _wa ) (3)
The pressure ratio calculation means 186 transmits the calculated pressure ratio P / P _H2 to the anode gas discharge amount calculation means 187.

(Anode gas discharge calculation means 187)
The anode gas discharge amount calculation means 187 plays a role of calculating the discharge amount of the anode gas to be discharged from the drain valve 4. Specifically, the anode gas discharge amount calculation means 187 first has the pressure ratio P / P _H2 transmitted from the pressure ratio calculation means 186 and 0 ° C. stored in advance in the required H ₂ discharge amount storage means 193 described later. Based on the required H ₂ emission amount V _H2 at 1 atmosphere, the anode gas emission amount V _a0 corresponding to the required H ₂ emission amount at 0 ° C. and 1 atmosphere is calculated by the following equation (4). Yes.
V _a0 = V _H2 × P / P _H2 Formula (4)

Then, the anode gas discharge amount calculation means 187 calculates the anode gas discharge amount V _a0 corresponding to the required H ₂ discharge amount at 0 ° C. and 1 atm based on the anode gas pressure and the anode gas temperature at the time of anode gas discharge. It is converted into an anode gas discharge amount V _a corresponding to the required H ₂ discharge amount under the anode gas temperature and pressure (hereinafter sometimes simply referred to as “anode gas discharge amount V _a ”).

Here, the required H ₂ emission amount V _H2 at 0 ° C. and 1 atm is stored in advance, but the present invention is not limited to this, and the required H ₂ emission amount at a predetermined temperature and atmospheric pressure is stored. V _H2 may be stored in advance, and the anode gas discharge amount obtained thereby may be converted by the temperature and pressure of the anode gas at the time of discharge.

(Second drain valve opening time calculating means 188)
The second drain valve opening time calculation means 188, on the basis of the anode gas emissions V _a calculated in the anode gas emission calculating unit 187, the drain valve open time T ₂ corresponding to the anode gas emissions (hereinafter, simply "drain The valve opening time T ₂ may be referred to as “. Specifically, the second drain valve opening time calculation means 188, an anode gas discharge amount calculating means on the basis of the anode gas emissions V _a calculated at 187, the anode is pre-stored in the correlation data storage unit 192 to be described later gas The drain valve opening time T ₂ is calculated with reference to the correlation data G corresponding to the correlation between the discharge amount V _a and the drain valve opening time T ₂ (see FIG. 5B). Further, the second drain valve opening time calculation means 188 transmits the calculated drain valve opening time T ₂ to the drain valve opening / closing control means 189.

(Drain valve opening / closing control means 189)
The drain valve opening / closing control means 189 plays a role of controlling the opening / closing of the drain valve 4 based on the drain valve opening time T ₁ corresponding to the water discharge amount and the drain valve opening time T ₂ corresponding to the anode gas discharge amount. It is. Specifically, the drain valve opening / closing control means 189 includes the drain valve opening time T ₁ corresponding to the water discharge amount transmitted from the first drain valve opening time calculating means 185 and the second drain valve opening time calculating means 188. The drain valve opening time T ₂ corresponding to the transmitted anode gas discharge amount is summed, and a control signal corresponding to the total time is generated and transmitted to the drain valve 4.

(Data storage means 109)
The data storage unit 109 is configured by, for example, a memory device, and includes a condensed water amount storage unit 191, a correlation data storage unit 192, and a required H ₂ discharge amount storage unit 193 as shown in FIG. The data storage unit 109 is connected to the control unit 108 and can read and write data. Since the condensed water amount storage means 191 is the same as the condensed water amount storage means 91 in the first embodiment, the description thereof will be omitted. Here, the correlation data storage means 192 and the required H ₂ emission amount storage means 193 are described. explain.

(Correlation data storage means 192)
The correlation data storage means 192 serves to store various correlations necessary for calculating the drain valve opening time based on the anode gas temperature, the anode gas pressure, and the cathode gas temperature as data. The correlation data storage unit 192 includes (A) a correlation between the water vapor partial pressure difference and the amount of condensed water, (B) a correlation between the water discharge amount and the drain valve opening time corresponding to the water discharge amount, and (C) the anode. Data corresponding to the three correlations between the gas discharge amount and the drain valve opening time corresponding to the anode gas discharge amount are stored. (B) Since the correlation between the water discharge amount and the drain valve opening time corresponding to the water discharge amount is the same as that in the first embodiment, here the correlation between (A) and (C) is shown in FIG. Will be described with reference to FIG.

(A) Correlation between water vapor partial pressure difference and amount of condensed water FIG. 9A is a diagram schematically showing the correlation between the water vapor partial pressure difference and the amount of condensed water. The water vapor partial pressure difference between condensation water, that the amount of generated water coming reversely transmitted to the anode electrode 22 as water vapor partial pressure difference △ P _w is large increases, there is the so-called proportional. This relationship can be obtained by experiment, for example.

(C) Correlation between the anode gas discharge amount and the drain valve opening time T ₂ FIG. 9B schematically shows the correlation between the anode gas discharge amount and the drain valve opening time corresponding to the anode gas discharge amount. It is a figure. The anode gas discharge amount and the drain valve opening time T ₂ are in a so-called proportional relationship. The relationship can be obtained by, for example, experiments, or can be set based on the opening diameter of the piping 3b serving as the discharge port or the drain valve 4.

(Requested H ₂ emission storage means 193)
The required H ₂ discharge amount storage means 193 plays a role of storing a required H ₂ discharge amount indicating the amount of H ₂ to be included in the anode gas to be discharged. The required H ₂ emission amount is defined by, for example, the volume of H ₂ (NL, normal liter) at 0 ° C. and 1 atm.

(Operation of the fuel cell system 100)
Next, the operation of the fuel cell system 100 according to the second embodiment will be described with reference to FIG. 8 (refer to FIGS. 6 to 9 as appropriate). FIG. 8 is a flowchart showing an operation flow of the fuel cell system.

(Step S101)
When the previous discharge of water and anode gas is completed, the anode water vapor partial pressure calculating means 181A acquires the anode gas temperature from the first temperature sensor 101 and calculates the water vapor partial pressure P _wa of the anode gas. Further, the cathode water vapor partial pressure calculating means 181B acquires the cathode gas temperature from the second temperature sensor 103, and calculates the water vapor partial pressure P _wc of the cathode gas. The anode water vapor partial pressure calculating unit 181A and the cathode water vapor partial pressure calculating unit 181B transmit the calculated water vapor partial pressures P _wa and P _wc to the water vapor partial pressure difference calculating unit 182.

(Step S102)
When the water vapor partial pressure difference calculating means 182 receives the water vapor partial pressure P _wa of the anode gas and the water vapor partial pressure P _wc of the cathode gas, the water vapor partial pressure difference calculating means 182 calculates the water vapor partial pressure difference ΔP _w using the equation (2). The water vapor partial pressure difference calculating unit 182 transmits the calculated water vapor partial pressure difference ΔP _w to the condensed water amount calculating unit 183.

(Step S103)
Condensation water calculating means 183 receives the water vapor partial pressure difference △ P _w, with reference to the correlation between the water vapor partial pressure difference between condensation water stored in the correlation data storage unit 192 (see FIG. 9 (a)), The amount of condensed water x _n per unit time at the anode electrode 22 is calculated. The condensed water amount calculating unit 183 stores the calculated condensed water amount per unit time x _n in the condensed water amount storage unit 191 in association with the measurement time t _n of the anode gas temperature and the cathode gas temperature. The condensed water amount storage means 191 is reset when, for example, the previous discharge of water and anode gas is completed.

(Step S104)
The water discharge amount calculation means 184 determines whether or not a predetermined time has elapsed since the previous discharge. If the predetermined time has not elapsed since the previous discharge (No at Step S104), the process returns to Step S101, and the amount of condensed water _xn per unit time is calculated again.

(Step S105)
When the predetermined time has elapsed since the previous discharge (step S104, Yes), the water discharge amount calculation means 184 sums the condensed water amount _xn stored in the condensed water amount storage means 191. To calculate the water discharge amount Σx. The water discharge amount calculation unit 184 transmits the calculated water discharge amount Σx to the first drain valve opening time calculation unit 185.

(Step S106)
When the first drain valve opening time calculation means 185 receives data on the water discharge amount Σx from the water discharge amount calculation means 184, the drain corresponding to the water discharge amount and the water discharge amount stored in advance in the correlation data storage means 192. The drain valve opening time T ₁ corresponding to the water discharge amount is calculated with reference to the correlation data E corresponding to the correlation with the valve opening time (see FIG. 4C). The first drain valve opening time calculation means 185 transmits the calculated drain valve opening time T ₁ to the drain valve opening / closing control means 189.

(Step S107)
Next, the pressure ratio calculation means 186 acquires the partial pressure of water vapor P _wa of the anode gas from the anode water vapor partial pressure calculation means, a total pressure P of the anode gas acquired from the pressure sensor 102, by the formula (3) The pressure ratio P / P _H2 between the total pressure P of the anode gas and the partial pressure P _H2 of H _{2 in} the anode gas is calculated. The pressure ratio calculation unit 186 transmits the calculated pressure ratio P / P _H2 to the anode gas discharge amount calculation unit 187.

(Step S108)
When receiving the pressure ratio P / P _H2 , the anode gas discharge amount calculation means 187 first obtains the required H ₂ discharge amount (NL) at 0 ° C. and 1 atm from the required H ₂ discharge amount storage means 193, By (4), the anode gas discharge amount V _a0 corresponding to the required H ₂ discharge amount at 0 ° C. and 1 atm is calculated.

Then, the anode gas discharge amount calculation means 187 refers to the anode gas temperature measured by the first temperature sensor 101 and the anode gas pressure measured by the pressure sensor 102 to obtain the required H ₂ discharge amount at 0 ° C. and 1 atm. The corresponding anode gas discharge amount V _a0 is converted into an anode gas discharge amount V _a corresponding to the required H ₂ discharge amount under the anode gas temperature and pressure at the time of discharge. Anode gas emission calculating unit 187 transmits the anode gas emissions V _a in terms of the second drain valve opening time calculation means 188.

(Step S109)
The second drain valve opening time calculation means 188, an anode receives the gas emissions V _a, the correlation (correlation data between the correlation data storage unit anode gas emissions stored in 192 V _a drain valve open time T ₂ With reference to G), the drain valve opening time T ₂ is calculated. The second drain valve opening time calculating means 188 transmits the calculated drain valve opening time T ₂ to the drain valve opening / closing control means 189.

(Step S110)
When the drain valve opening / closing control means 189 receives the drain valve opening time T ₁ and the drain valve opening time T ₂ , the drain valve opening / closing control means 189 generates a control signal corresponding to these total times and transmits it to the drain valve 4. As a result, the drain valve 4 is opened for a total time of the drain valve opening time T ₁ corresponding to the water discharge amount and the drain valve opening time T ₂ corresponding to the anode gas discharge amount, and the gas-liquid separator 3 And the anode gas containing H ₂ corresponding to the required H ₂ emission amount are discharged.

  The configuration and operation of the fuel cell system 100 according to the second embodiment have been described above, but the present invention is not limited to the second embodiment.

For example, the fuel cell system 100 according to the second embodiment discharges the water separated by the gas-liquid separator 3 and the anode gas in the pipe from the drain valve 4. You may make it carry out by the well-known control method. The anode gas may be discharged from an anode gas purge valve (not shown), and only the water separated by the gas-liquid separator 3 may be discharged from the drain valve 4. In such a case, the pressure sensor 102, the pressure ratio calculating means 186, the anode gas discharge amount calculating means 187, and the second drain valve opening time calculating means 188 can be omitted. Further, the required H ₂ discharge amount storage means 193 and the correlation (correlation data G) between the anode gas discharge amount and the drain valve opening time can be omitted.

  In the second embodiment, the cathode water vapor partial pressure is calculated based on the cathode gas temperature. In addition to the second temperature sensor 103, a humidity sensor that measures the humidity of the cathode gas is provided, and the humidity The cathode water vapor partial pressure may be calculated based on the cathode gas humidity measured by the sensor.

  In the second embodiment, the anode water vapor partial pressure is calculated based on the anode gas temperature. In addition to the first temperature sensor 101, a humidity sensor for measuring the anode gas humidity is provided, and the humidity sensor The anode water vapor partial pressure may be measured based on the anode gas humidity measured in step (1).

  Further, by paying attention to the operation of the fuel cell system according to the first embodiment and the second embodiment, or each configuration of the control means, the present invention provides a control method of the fuel cell system, and further a fuel cell system. It can also be regarded as a control program for causing a computer to function as each of the means for controlling.

1 is a schematic configuration diagram illustrating a fuel cell system according to a first embodiment of the present invention. It is the block diagram which showed the structure of ECU used for 1st Embodiment of this invention. It is the flowchart which showed the flow of operation | movement of the fuel cell system which concerns on 1st Embodiment of this invention. (A) is the figure which showed typically the correlation with an electric power generation current value, anode gas temperature, and the amount of dew condensation water, (b) explains the relationship between the amount of dew condensation water per unit time and the measurement time of anode gas temperature. (C) is a diagram schematically showing the correlation between the water discharge amount and the drain valve opening time corresponding to the water discharge amount. (A) is a diagram schematically showing the correlation between the generated current value and the required H ₂ emission amount, and (b) is a diagram illustrating the drain opening corresponding to the required H ₂ emission amount, the anode gas temperature, and the anode gas emission amount. It is the figure which showed the correlation with valve time typically. It is the schematic block diagram which showed the fuel cell system which concerns on 2nd Embodiment of this invention. It is the block diagram which showed the structure of ECU used for 2nd Embodiment of this invention. It is the flowchart which showed the flow of operation | movement of the fuel cell system which concerns on 2nd Embodiment of this invention. (A) is the figure which showed typically the correlation of water vapor | steam partial pressure difference and the amount of dew condensation water, (b) is a model showing the correlation with the drain valve opening time corresponding to anode gas discharge | emission amount and anode gas discharge | emission amount. FIG. It is a graph which shows correlation with temperature T (degreeC) and saturated water vapor pressure E (hPa) in an anode pole and a cathode pole.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell system 2 Fuel cell 3 Gas-liquid separator 4 Drain valve 5 Temperature sensor 6 Current sensor 6a External circuit 7 ECU
8 Control means 9 Data storage means 11 Hydrogen tank 12 Ejector 13 Compressor 14 Drive unit 21 Electrolyte membrane 22 Anode electrode 23 Cathode electrode

Claims (10)

A fuel cell having an anode and a cathode sandwiching an electrolyte;
A gas-liquid separator that is installed on the flow path of the anode gas discharged from the anode electrode and separates water contained in the anode gas;
A drain valve for opening and closing a discharge port for discharging water collected by the gas-liquid separator;
A temperature sensor for measuring the anode gas temperature;
A current sensor for measuring a generated current value in the fuel cell;
Control means for controlling the opening and closing of the drain valve, and a fuel cell system comprising:
The control means includes
Based on the anode gas temperature and the generated current value, a drain valve opening time corresponding to a water discharge amount determined from an amount of water recovered by the gas-liquid separator is calculated, and based on the drain valve opening time. And opening and closing the drain valve. The control means includes
A condensed water amount calculating means for calculating a condensed water amount per unit time based on a correlation stored in advance between the generated current value, the anode gas temperature, and the amount of condensed water, the anode gas temperature, and the generated current value;
Water discharge amount calculating means for calculating a water discharge amount determined from the amount of water collected by the gas-liquid separator based on the amount of condensed water per unit time;
A first valve opening time corresponding to the water discharge amount is calculated based on a previously stored correlation between the water discharge amount and the drain valve opening time corresponding to the water discharge amount and the water discharge amount. Drain valve opening time calculating means;
The fuel cell system according to claim 1, further comprising: a drain valve opening / closing control unit that controls opening / closing of the drain valve based on a drain valve opening time corresponding to the water discharge amount. The control means further includes
The drain valve opening time corresponding to the anode gas discharge amount is calculated based on the anode gas temperature and the required H ₂ discharge amount, and the drain valve opening time corresponding to the water discharge amount and the anode gas discharge amount are corresponded. The fuel cell system according to claim 1 or 2, wherein the drain valve is opened and closed based on a drain valve opening time. The control means includes
Anode gas discharge based on the correlation stored in advance with the anode gas temperature, the required H ₂ discharge amount, and the drain valve opening time corresponding to the anode gas discharge amount, the anode gas temperature, and the required H ₂ discharge amount A second drain valve opening time calculating means for calculating a drain valve opening time corresponding to the amount;
The drain valve opening / closing control means includes
4. The fuel cell system according to claim 3, wherein opening and closing of the drain valve is controlled based on a drain valve opening time corresponding to the anode gas discharge amount and a drain valve opening time corresponding to the water discharge amount. . A fuel cell having an anode and a cathode with an electrolyte interposed therebetween;
A gas-liquid separator installed on the flow path of the anode gas discharged from the anode electrode and separating water contained in the anode gas;
A drain valve for opening and closing a discharge port for discharging water collected by the gas-liquid separator;
A first temperature sensor for measuring the anode gas temperature;
A second temperature sensor for measuring the cathode gas temperature;
Control means for controlling the opening and closing of the drain valve, and a fuel cell system comprising:
The control means includes
Based on the anode gas temperature and the cathode gas temperature, a drain valve opening time corresponding to the water discharge amount determined from the amount of water recovered by the gas-liquid separator is calculated, and the water discharge amount is corresponded. A fuel cell system, wherein the drain valve is opened and closed based on a drain valve opening time. The control means includes
A water vapor partial pressure difference calculating means for calculating a water vapor partial pressure difference between the cathode gas and the anode gas based on the anode gas temperature and the cathode gas temperature;
Based on the correlation stored in advance between the water vapor partial pressure difference and the amount of condensed water per unit time at the anode electrode, and the water vapor partial pressure difference, the condensed water amount calculating means for calculating the amount of condensed water per unit time at the anode electrode;
Water discharge amount calculating means for calculating a water discharge amount determined from the amount of water recovered by the gas-liquid separator based on the amount of condensed water per unit time;
First drain valve opening time calculating means for calculating a drain valve opening time corresponding to the water discharge amount based on the correlation stored in advance between the water discharge amount and the drain valve opening time and the water discharge amount; ,
6. The fuel cell system according to claim 5, further comprising drain valve opening / closing control means for controlling opening / closing of the drain valve based on a drain valve opening time corresponding to the water discharge amount. The fuel cell system includes:
A pressure sensor for measuring the anode gas pressure;
The control means includes
Based on the anode gas temperature, the anode gas pressure, and the required H ₂ discharge amount, a drain valve opening time corresponding to the anode gas discharge amount is calculated, and the drain valve opening time corresponding to the water discharge amount and the The fuel cell system according to claim 6, wherein the drain valve is opened and closed based on a drain valve opening time corresponding to the anode gas discharge amount. The control means includes
An anode gas discharge amount setting means for setting an anode gas discharge amount based on the anode gas temperature, the anode gas pressure, and the required H ₂ discharge amount;
A second drain valve opening time for calculating a drain valve opening time corresponding to the anode gas discharge amount based on the correlation stored in advance between the anode gas discharge amount and the drain valve opening time and the anode gas discharge amount. And a calculating means,
The drain valve opening / closing control means includes
8. The fuel cell system according to claim 7, wherein opening and closing of the drain valve is controlled based on a drain valve opening time corresponding to the anode gas discharge amount and a drain valve opening time corresponding to the water discharge amount. . The anode gas discharge amount setting means includes:
An anode water vapor partial pressure calculating means for calculating a water vapor partial pressure in the anode gas based on the anode gas temperature;
Pressure ratio calculating means for calculating a pressure ratio between the total pressure of the anode gas and the partial pressure of hydrogen based on the anode gas pressure and the water vapor partial pressure;
A pressure ratio between the total pressure of the anode gas calculated by the pressure ratio calculating means and a partial pressure of hydrogen, the required H ₂ emission amount under a predetermined temperature and a predetermined pressure, the anode gas pressure, and the anode gas temperature 9. A fuel cell system according to claim 8, further comprising: an anode gas discharge amount calculating means for calculating an anode gas discharge amount corresponding to the pressure and temperature of the anode gas when discharging the anode gas based on the above. A first humidity sensor for measuring anode gas humidity and / or a second humidity sensor for measuring cathode gas humidity;
The water vapor partial pressure difference calculating means calculates a pressure difference between the water vapor partial pressures of the cathode gas and the anode gas based on the anode gas temperature, the cathode gas temperature, the anode gas humidity and / or the cathode gas humidity. The fuel cell system according to any one of claims 6 to 9, wherein

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