JP2008243782A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of making a compact and lightweight valve for controlling fuel discharge gas discharged from a fuel discharge gas passage of an anode system of a fuel cell. <P>SOLUTION: The fuel cell system 1 comprises a fuel cell 10, a fuel gas supply passage 11, an oxidant gas supply passage 12, a fuel gas circulation passage 14, a fuel discharge gas passage 15, and at least either a purge means 41 or a scavenging means 30. The fuel cell system 1 has an opening and closing valve 42, which is arranged on the fuel discharge gas passage 15 in series, capable of opening and closing, a flow rate adjusting valve 43 capable of adjusting a flow rate, and a control device 60 for controlling at least either of a purging flow rate at the time of purging of the purge means 41 and a scavenging flow rate at the time of scavenging of the scavenging means 30 by controlling the opening and closing valve 42 and the flow rate adjusting valve 43. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell system capable of adjusting a flow rate of fuel exhaust gas discharged from an anode of a fuel cell.

  2. Description of the Related Art Conventionally, in a fuel cell system mounted on a vehicle or the like, as disclosed in Patent Document 1, for example, a purge valve (hydrogen purge valve) is used to discharge impurities and moisture in the anode system during traveling. Indispensable and always used. In addition, in the fuel cell system, the anode system is prevented from freezing and clogging below freezing point, and when scavenging the entire system when the ignition is OFF, a scavenging discharge valve for scavenging and discharging a large flow of air ( Air discharge valve) is indispensable and always used.

In the fuel cell system, the purge flow rate at the time of purging and the scavenging flow rate at the time of scavenging are greatly different from each other on the system, so the purge valve is composed of a valve corresponding to a small flow rate, and the scavenging discharge valve corresponds to a large flow rate. It consists of a valve. Therefore, in the fuel cell system, the two valves having different flow characteristics are arranged in parallel in the anode off-gas discharge system in an independent state.
Since the two valves are both used below freezing point, they are designed to move even in a frozen state (for example, see Patent Document 2).

JP 2006-134807 A (FIG. 1) Japanese Patent Laying-Open No. 2005-265036 (FIG. 2)

  However, in the conventional fuel cell system described in Patent Document 1 and the like, all the valves for discharging the fuel exhaust gas (anode off gas) are configured so that they can operate even in an environment below freezing point. The problem is that the cost is high due to the large number of parts.

  In the conventional fuel cell system, two types of valves, a purge valve and a scavenging exhaust valve, are arranged in parallel according to the flow rate characteristics during purging and scavenging, which increases the weight and costs. Therefore, it has been a big problem to reduce the weight and reduce the cost.

  Usually, the anode off-gas exhaust system valve is required to have a function of completely shutting off fuel exhaust gas such as hydrogen, and there is a problem that a flow rate adjusting valve such as a butterfly valve or a needle valve cannot be used.

  In addition, in order to make these types of flow rate control valves function in a frozen state, it is necessary to increase the size of the actuator that drives the flow rate control valve and to install a freeze prevention heater. As a result, the number of parts and the cost increase.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel cell system that can reduce the size and weight of a valve that controls fuel exhaust gas discharged from an anode fuel exhaust path of a fuel cell.

  As a means for solving the above-mentioned problem, the invention of the fuel cell system according to claim 1 includes a fuel cell that generates power by reacting a fuel gas supplied to the anode and an oxidant gas supplied to the cathode. A fuel gas supply path for supplying the fuel gas to the anode, an oxidant gas supply path for supplying an oxidant gas to the cathode, and a fuel gas circulation for returning the fuel gas that has passed through the anode to the fuel gas supply path A fuel exhaust path for discharging the fuel exhaust gas from the anode, a purge means for purging the fuel exhaust gas from the fuel exhaust path, and a scavenging gas is introduced into the anode, and the anode and the fuel gas circulation path And at least one of scavenging means for scavenging residual gas in the fuel exhaust gas passage, in the fuel exhaust gas passage An on-off control valve and a flow rate adjustment valve arranged in series, a flow rate adjustment valve capable of adjusting the flow rate, and the on-off valve and the flow rate adjustment valve are controlled, whereby the purge flow rate when purging by the purge means and the scavenging means are controlled. And control means for controlling at least one of the scavenging flow rates during scavenging.

According to the fuel cell system of the first aspect of the present invention, the on-off valve that can be controlled to open and close and the flow rate adjustment valve that can adjust the flow rate are arranged in series in the fuel exhaust gas path to control the on-off valve and the flow rate adjustment valve. By controlling by means, the discharge flow rate of the fuel exhaust gas can be adjusted. As a result, the on-off valve and the flow rate adjustment valve have a low shut-off sealing property and an operating differential pressure, so that the entire valve can be reduced in size. That is, in the fuel cell system, the entire valve can be reduced in size and weight as compared with the conventional case in which two valves having different flow characteristics are arranged in parallel.
Further, the fuel cell system is provided with a control means for controlling at least one of the purge flow rate at the time of purging by the purge means and the scavenging flow rate at the time of scavenging by the scavenging means, so that discharge is performed in accordance with the operating conditions of the fuel cell system. It is possible to arbitrarily change the flow rate. As a result, the fuel cell system can appropriately suppress unnecessary purging and scavenging and improve fuel efficiency.
Note that when both the purge means and the scavenging means are provided and both the purge and the scavenging are performed, the exhaust flow rate of the fuel exhaust gas can be controlled more efficiently, and the fuel consumption can be further improved. .

The invention of the fuel cell system according to claim 2 is the fuel cell system according to claim 1, wherein the on-off valve is constituted by a valve device that has taken a countermeasure against freezing, and upstream of the flow rate adjustment valve. It is arranged on the side.
Here, the anti-freezing measure is a measure for preventing moisture contained in the gas passing through the on-off valve from freezing due to a decrease in temperature and making the valve body incapable of being opened and closed. It is not limited. Freezing measures include, for example, a structure that prevents freezing by preventing water from accumulating in the valve body device, and the possibility of water accumulation by placing the valve body and valve seat higher than the bottom of the flow path in the valve. Measures such as a structure that separates the valve body from a certain part to prevent the valve body from freezing and a structure that prevents water from entering the inside of the actuator can be cited.

  According to the invention of the fuel cell system according to claim 2, the on-off valve is constituted by a valve device that has been subjected to anti-freezing measures, and disposed on the upstream side of the flow regulating valve, so that after the valve device stops, It is possible to prevent the flow rate adjusting valve from malfunctioning due to condensation or freezing of water vapor in the gas in the anode system. As a result, the flow rate adjusting valve arranged on the downstream side can maintain the flow rate adjusting function even when it is below freezing point.

  A fuel cell system according to a third aspect is the fuel cell system according to the first or second aspect, wherein the on-off valve and the flow rate adjusting valve are integrally formed.

  According to the fuel cell system of the present invention, since the on-off valve and the flow rate adjusting valve are integrally formed, the number of valves and the number of parts in the fuel cell system are reduced, thereby reducing the cost. Can be achieved.

  A fuel cell system according to a fourth aspect of the present invention is the fuel cell system according to any one of the first to third aspects, wherein the control means is configured to stop the fuel cell system when the fuel cell system stops. The fuel cell system is stopped after setting the flow rate adjusting valve to a purge flow rate to be performed at the next startup.

  According to the fuel cell system of the present invention, when the fuel cell device is stopped, the fuel cell system is started by stopping the flow rate adjusting valve after setting the flow rate adjusting valve to a purge flow rate to be performed next time. In this case, it is possible to eliminate the setting of the purge flow rate by operating the flow rate adjustment valve.

  According to the fuel cell system of the present invention, the valve for controlling the fuel exhaust gas discharged from the fuel exhaust system of the anode system of the fuel cell can be reduced in size and weight. In addition, it is possible to provide a fuel cell system capable of controlling the flow rate of the fuel exhaust gas discharged from the fuel exhaust gas passage in a wide range from a small flow rate to a large flow rate.

Hereinafter, a fuel cell system according to an embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a block diagram showing the configuration of the fuel cell system according to the present embodiment.

≪Configuration of fuel cell system≫
As shown in FIG. 1, the fuel cell system 1 is a system that is mounted on a fuel cell vehicle that travels by rotating a traveling electric motor (traveling motor) with power generated by the fuel cell 10, for example. When the fuel cell vehicle is stopped (when the fuel cell 10 is stopped), scavenging gas is supplied to the fuel cell 10 and the fuel gas supply path 11 and the oxidant gas supply path 12 of the fuel cell 10 are scavenged. The fuel cell system 1 includes a fuel cell 10, a fuel gas supply path 11, an oxidant gas supply path 12, a scavenging gas introduction path 13, a fuel gas circulation path 14, a fuel exhaust gas path 15, which will be described later, A fuel exhaust gas dilution means 40, a scavenging means 30, a purge means 41, an on-off valve 42, a flow rate adjustment valve 43, a pressure adjustment valve 51, and a control device (control means) 60 are provided. In the fuel cell system 1, it is sufficient that at least one of the scavenging means 30 and the purging means 41 is provided. Hereinafter, the fuel cell system 1 having both the scavenging means 30 and the purge means 41 and controlled by the control device 60 will be described as an example.

≪Configuration of fuel cell≫
A fuel cell 10 (fuel cell stack) shown in FIG. 1 mainly has a monovalent cation exchange type electrolyte membrane sandwiched between an anode (fuel electrode) 10a and a cathode (air electrode) 10b on which a catalyst is supported. Polymer Electrolyte Fuel Cell, in which a plurality of single cells each comprising a membrane electrode assembly (MEA) 10c and a separator sandwiching the MEA are stacked. PEFC). The fuel cell 10 is configured to generate power by reacting a fuel gas such as hydrogen supplied to the anode 10a with an oxidant gas such as humidified air supplied to the cathode 10b.

≪Configuration of fuel gas supply path≫
As shown in FIG. 1, the fuel gas supply path 11 is an anode-type supply path that supplies the fuel gas in the fuel gas tank 21 to the anode 10 a of the fuel cell 10. The fuel gas supply path 11 includes, for example, a fuel gas tank 21, a shutoff valve 22, a regulator 23, a filter 24, a heat exchanger 25, and an ejector 26. For example, a scavenging gas supply path 17 may be connected to the fuel gas supply path 11 between the shutoff valve 22 and the regulator 23. In this way, scavenging of the fuel gas supply path (between the pipe 21a and the pipe 26a) 11 indicated by the arrow A in FIG. 1 is possible, and the entire scavenging can be performed.

The fuel gas tank 21 is a tank in which hydrogen or the like as a fuel gas is stored, and is connected to the shutoff valve 22 via a pipe 21a.
The shut-off valve 22 is an electromagnetic valve that adjusts the outflow of the fuel gas flowing out from the fuel gas tank 21, and is connected to the regulator 23 via the pipe 22a. The shut-off valve 22 is electrically connected to the control device 60, and the valve body is appropriately controlled to open and close by the control device 60.

  The regulator 23 includes a pressure reducing valve for adjusting the fuel gas to a predetermined pressure, and a filter 24 for purifying the fuel gas is provided on the downstream side. The regulator 23 is electrically connected to the control device 60, and the pressure of the fuel gas is controlled to be reduced by a drive signal of the control device 60. The regulator 23 is connected to the heat exchanger 25 via a filter 24 and a pipe 24a.

The heat exchanger 25 is a device for exchanging and reducing the heat generated when the fuel gas is decompressed by the regulator 23, and is connected to the ejector 26 via a pipe 25a.
The ejector 26 is a device for circulating the anode off-gas containing unreacted hydrogen discharged from the anode 10a of the fuel cell 10 to the fuel gas circulation path 14, and the fuel gas inlet of the fuel cell 10 via the pipe 26a. It is connected to the.

≪Configuration of oxidant gas supply path≫
As shown in FIG. 1, the oxidant gas supply path 12 is a supply path that supplies an oxidant gas such as air to the cathode 10 b of the fuel cell 10. The oxidant gas supply path 12 is connected to, for example, a compressor (not shown) for sending the oxidant gas at one end side, a humidifier (not shown) for humidifying the oxidant gas, and the other end side. It is connected to the cathode 10b by a pipe 12a.

≪Configuration of scavenging gas introduction path≫
As shown in FIG. 1, the scavenging gas introduction path 13 is a flow path for guiding the scavenging gas (oxidant gas such as air) from the cathode system to the anode system when scavenging the fuel cell 10. 31 is mainly provided.

<Configuration of scavenging introduction valve>
The scavenging introduction valve 31 is an electromagnetic valve for opening and closing the scavenging gas introduction passage 13. The scavenging gas introduction passage 31 shuts off the communication between the oxidant gas supply passage 12 and the fuel gas supply passage 11 when the fuel cell 10 generates power. This is an electromagnetic valve that opens the valve body and introduces the oxidant gas in the oxidant gas supply path 12 into the fuel gas supply path (pipe 26a) 11. The scavenging introduction valve 31 is electrically connected to the control device 60 and is controlled to be opened and closed so that the valve body is opened by the drive signal of the control device 60 and the scavenging gas flows from the scavenging gas introduction passage 13 to the anode system. The The scavenging introduction valve 31 has an upstream side connected to the cathode system pipe 12a through a pipe 31a and a downstream side connected to the anode system pipe 26a through a pipe 31b.

<Configuration of scavenging means>
When the fuel cell system 1 is stopped, the scavenging means 30 opens the scavenging introduction valve 31 to introduce scavenging gas (oxidant gas) from the scavenging gas introduction path 13 to the anode 10a, and the anode 10a and the fuel gas circulation path 14 The residual gas is scavenged through the fuel exhaust gas passage 15. The scavenging means 30 includes a scavenging gas introduction path 13, a scavenging introduction valve 31, a fuel gas circulation path 14, an ejector 26, a fuel exhaust gas path 15 to be described later, an on-off valve 42, and a flow rate adjustment valve 43. It is mainly composed.

≪Configuration of fuel gas circuit≫
As shown in FIG. 1, the fuel gas circulation path 14 is a circulation path for returning the fuel gas that has passed through the anode 10a to the fuel gas supply path 11, the upstream side being connected to the fuel cell 10, and the downstream side being an ejector. 26.

≪Configuration of fuel exhaust path≫
The fuel exhaust gas passage 15 is a passage for discharging fuel exhaust gas from the anode 10 a of the fuel cell 10. The fuel exhaust gas passage 15 is provided with an on-off valve 42 that constitutes the purge means 41, a flow rate adjusting valve 43, and a diluter 44 that constitutes the fuel exhaust gas dilution means 40. In the fuel exhaust gas passage 15, an on-off valve 42 capable of controlling the opening and closing of the fuel exhaust gas passage 15 and a flow rate adjusting valve 43 capable of adjusting the flow rate are arranged in series.

≪Configuration of purge means≫
The purge means 41 is mainly intended to appropriately discharge moisture and other impurities mixed in the fuel gas circulation path 14 during operation of the fuel cell system 1. The purge means 41 is configured to send the oxidant gas in the oxidant gas supply path 12 from the scavenging gas introduction path 13 to the fuel gas circulation path 14 and push off the off-gas in the fuel gas circulation path 14 to the fuel exhaust gas path 15. Has been. The purge means 41 includes, for example, a scavenging gas introduction path 13, a scavenging introduction valve 31, a fuel gas circulation path 14, an ejector 26, a fuel exhaust gas path 15, an on-off valve 42, a flow rate adjustment valve 43, and a diluter. 44.

<Configuration of on-off valve>
The on-off valve 42 is an electromagnetic valve for opening and closing the fuel exhaust gas passage 15 for discharging the fuel exhaust gas from the fuel cell 10, and the upstream side is connected to the fuel cell 10 by the pipe 15a, and the downstream side is the flow rate adjusting valve 43 by the channel 42a. It is connected to the. The on-off valve 42 is composed of a valve device that has taken measures against freezing and is disposed upstream of the flow rate adjusting valve 43. The on-off valve 42 is electrically connected to the control device 60, and is configured such that the valve body is controlled to open and close by a drive signal of the control device 60.

<Configuration of flow control valve>
The flow rate adjusting valve 43 is a valve for adjusting (reducing) the flow rate of the fuel gas flowing from the on-off valve 42 during purging and scavenging, and then flowing it to the downstream diluter 44. The on-off valve 42 is connected, and the downstream side is connected to the diluter 44 by a pipe 43a. The flow rate adjusting valve 43 is electrically connected to the control device 60, and is configured such that the valve body is controlled to open and close to an appropriate opening degree by a drive signal of the control device 60.

≪Configuration of fuel exhaust gas dilution means≫
The fuel exhaust gas dilution means 40 dilutes the fuel exhaust gas discharged from the fuel exhaust gas passage 15 connected to the fuel cell 10 with the diluent gas (oxidant gas) by the diluter 44 and discharges it to the atmosphere. It is a device.

<Configuration of the diluter>
The diluter 44 oxidizes a fuel exhaust gas such as hydrogen as an oxidant gas in a dilute gas introduction path (not shown) connected to the oxidant gas supply path 12 or an oxidant gas sent from the oxidant gas discharge path 16. This is a device for diluting with a diluent gas such as (cathode off-gas) and adjusting the flow rate and discharging it from the pipe 44a to the outside of the fuel cell vehicle.

≪Configuration of oxidant gas discharge passage≫
A flow path for discharging the cathode off-gas discharged from the cathode 10b of the fuel cell 10, the upstream side being connected to the cathode 10b and the downstream side being connected to the diluter 44 via a pressure adjusting valve 51 for adjusting the internal pressure. It is connected.

≪Configuration of control device (control means) ≫
In addition to the above, the control device 60 controls the on-off valve 42 and the flow rate adjusting valve 43 to control the purge flow rate when purging by the purge means 41 and the scavenging flow rate when scavenging by the scavenging means 30. It has a function. In addition, when the fuel cell system 1 stops, the control device 60 is configured to stop after setting the flow rate adjustment valve 43 to the purge flow rate that is performed at the next startup. The control device 60 is connected to an ignition switch (not shown), and operates in conjunction with ON / OFF of the ignition switch. The control device 60 includes, for example, a CPU, ROM, RAM, various interfaces, electronic circuits, and the like.

  More specifically, for example, due to a decrease in the cell voltage of any single cell constituting the fuel cell 10, it is estimated that the amount of water in the fuel off-gas (that is, the amount of water in the anode 10a) and the concentration of different gases are high. (When purging), the control device 60 has a function of opening the on-off valve 42 and the flow rate adjusting valve 43 and sending the fuel off-gas having a high water content to the diluter 44 through the pipe 43a.

On the other hand, when the cell voltage of each single cell is a good value and the amount of water in the fuel off-gas is estimated to be appropriate (during fuel circulation), the control device 60 controls the on-off valve 42 and the flow rate adjustment valve 43. The fuel gas is closed and returned to the ejector 26 from the fuel gas circulation path 14 so that the fuel gas is circulated and used efficiently.
However, the hydrogen purge method is not limited to a method based on such a cell voltage, and other methods may be used.

≪Operation of fuel cell system≫
Next, the operation of the fuel cell system 1 will be described with reference to FIG.
First, generation of electric power of the fuel cell 10 will be described.
As shown in FIG. 1, the fuel cell 10 includes a fuel gas (a fuel gas supplied from a fuel gas tank 21 via a fuel gas supply path 11 and an apparatus such as an ejector 26 installed in the fuel gas supply path 11). Hydrogen and electric power and heat are generated by an electrochemical reaction between a compressor (not shown) and an oxidant gas (oxygen) supplied through an oxidant gas supply path 12.

Next, the state at the time of steady operation of the fuel cell system 1 will be described.
During steady operation of the fuel cell system 1, the scavenging introduction valve 31, the on-off valve 42, and the flow rate adjustment valve 43 are closed by the control device 60. Therefore, the fuel gas sent from the ejector 26 to the anode 10a is circulated so as to return to the anode 10a again through the fuel gas circulation path 14. In this way, useless consumption of fuel gas is reduced.

Next, the state at the time of purging will be described.
When the on-off valve 42 and the flow rate adjustment valve 43 shown in FIG. 1 are opened and purged during traveling, the fuel exhaust gas is sent from the fuel cell 10 to the fuel exhaust gas passage 15, the on-off valve 42, the flow rate adjustment valve 43, and the diluter. It is discharged to the outside of the fuel cell system 1 through 44.

  At this time, the flow rate of the fuel exhaust gas discharged from the on-off valve 42 is adjusted by operating the flow rate adjusting valve 43 disposed downstream thereof with a drive signal from the control device 60. The fuel exhaust gas further flows with the flow rate suppressed by the diluter 44. In the diluter 44, cathode off-gas (diluted gas) flows from the oxidant gas discharge passage 16 and joins, and fuel exhaust gas such as hydrogen is mixed and diluted, and then exhausted to the outside through the pipe 44a.

A state during scavenging will be described.
Then, when the power generation state of the fuel cell 10 is stopped and the pressure of the fuel gas in the fuel gas circulation path 14 is reduced, the scavenging introduction valve 31 and the on-off valve are controlled by the sensor (not shown) and the control device 60. 42 and the flow regulating valve 43 are opened. Then, the fuel gas in the fuel gas circulation path 14 is discharged from the pipe 44 a to the outside through the fuel exhaust gas path 15, the on-off valve 42, the flow rate adjusting valve 43, and the diluter 44.

  That is, the scavenging introduction valve 31 is switched to an ON state and opened by a drive signal from the control device 60. Then, the oxidant gas (scavenging gas) from the compressor (not shown) flows into the fuel gas supply path 11 through the oxidant gas supply path 12 and the scavenging gas introduction path 13, and the anode 10a, the fuel exhaust gas path 15, The fuel off-gas (residual gas) that has been discharged to the outside through the on-off valve 42, the flow rate adjusting valve 43, and the diluter 44 and circulated through the fuel gas circulation path 14 is purged.

Next, the case where scavenging is completed will be described.
When the scavenging of the fuel gas is completed and the fuel cell 10 returns to the normal power generation state, the control device 60 opens the shut-off valve 22 and the regulator 23 from the fuel gas supply path 11 via the ejector 7. While the fuel gas is sent to the anode 10a, the scavenging introduction valve 31, the on-off valve 42, and the flow rate adjusting valve 43 are shut off. Then, the fuel gas discharged from the anode 10a is circulated again to return to the anode 10a through the fuel gas circulation path 14 and the ejector 26.

  At this time, the on-off valve 42 and the flow rate adjusting valve 43 are closed by an OFF signal from the control device 60, whereby the fuel exhaust gas passage 15 is shut off and the oxidant gas (scavenging gas) is supplied to the fuel gas circulation passage 14. The scavenging is stopped.

The stop time of the fuel cell system 1 will be described.
When the fuel cell system 1 is stopped, the control device 60 controls the drive so that the fuel cell system 1 is stopped after setting the flow rate adjusting valve 43 to a purge flow rate to be performed at the next startup. For this reason, when the fuel cell system 1 is started, it is possible to eliminate setting the purge flow rate by operating the flow rate adjustment valve 43.

  As described above, in the present embodiment, the on-off valve 42 and the flow rate adjustment valve 43 that can adjust the flow rate are arranged in series in the fuel exhaust gas passage 15, so that the fuel can be generated by the on-off valve 42 and the flow rate adjustment valve 43. The exhaust flow rate of the exhaust gas flowing through the exhaust gas passage 15 can be adjusted, and the fuel exhaust gas passage 15 can be reliably closed. As a result, the on-off valve 42 and the flow rate adjusting valve 43 have improved shut-off sealing performance and lower operating differential pressure, so that the entire valve can be reduced in size and weight.

  In the fuel cell system 1, the on-off valve 42 with anti-freezing measures is arranged on the upstream side of the flow rate adjustment valve 43, so that after the on-off valve 42 and the flow rate adjustment valve 43 are stopped, the water vapor in the gas in the anode system The flow regulating valve 43 is prevented from malfunctioning due to condensation and freezing, and the flow regulating function can be maintained even below freezing.

  Further, the fuel cell system 1 controls the purge flow rate at the time of purging by the purge means 41 and the scavenging flow rate at the time of scavenging by the scavenging means 30 by the flow rate adjusting valve 43 that is operated by the drive signal of the control device 60, thereby It becomes possible to arbitrarily change the discharge flow rate according to the operating conditions of the battery system 1. As a result, the fuel cell system 1 can suppress unnecessary purge and improve fuel efficiency.

≪Modification≫
The present invention is not limited to the above-described embodiment, and various modifications and changes can be made within the scope of the technical idea. The present invention extends to these modifications and changes. Of course.

FIG. 2 is a view showing a modification of the fuel cell system according to the present embodiment, and is a cross-sectional view showing a composite valve in which an on-off valve and a flow rate adjustment valve are integrated.
In the above-described embodiment, as shown in FIG. 1, the case where the on-off valve 42 and the flow rate adjusting valve 43 are arranged in series in the fuel exhaust gas passage 15 has been described, but the present invention is not limited to this, as shown in FIG. 2. Alternatively, the on-off valve 46 (42) and the flow rate adjustment valve 47 (43) may be integrated into a composite valve 45.

  In this case, for example, the composite valve 45 is configured such that a valve body 461 of a solenoid-driven on-off valve 46 and a valve body 471 of a step motor-driven flow rate adjusting valve 47 are fixed and integrated. The composite valve 45 is provided on the on-off valve 46 side and connected to the piping 15a connected to the fuel cell 10 (see FIG. 1), and the diluter 44 (see FIG. 1), and a lead-out flow path 472 to which a pipe 43a connected to the pipe 43a is connected.

  The on-off valve 46 is, for example, an electromagnetic that opens and closes the 464 by operating the plunger 466 provided with the valve body 464 by the magnetic force generated when the drive current from the control device 60 (see FIG. 1) flows through the coil of the solenoid 467. It is a valve. The on-off valve 46 includes the valve body 461, an introduction passage 462 formed by the valve body 461, a valve seat 463 provided in the introduction passage 462, a valve body 464 for opening and closing the valve seat 463, A valve spring 465 for pressing and closing the valve body 464 against the valve seat 463, a plunger 466 provided with a valve body 464 at the tip, a solenoid 467 for operating the plunger 466, and a guide for supporting the plunger 466 so as to advance and retract. A member 468, a diaphragm D having a central side fixed to the plunger 466 and an external week side fixed to the guide member 468, and a housing 469 are configured.

  For example, the flow rate adjusting valve 47 is a composite valve that is configured such that a rotor 476 that rotates with a drive current from a control device 60 (see FIG. 1) is actuated on a coil 475 of a step motor 474 via a screw mechanism. 45 is a valve device that adjusts the flow rate of the fuel exhaust gas flowing through the interior of the engine. The flow rate adjusting valve 47 is provided in the outlet channel 472 and the outlet channel 472 formed by the valve body 471, the valve body 471, and adjusts the flow rate of the outlet channel 472. The needle valve body 473, a coil 475 of the step motor 474, and a rotor 476 of the step motor 474 that rotates by the magnetic force of the coil 475 and advances and retracts the needle valve body 473 via a screw mechanism are configured. .

  As described above, the on-off valve 46 is the composite valve 45 in which the flow rate adjusting valve 47 is integrated, thereby reducing the number of valves and the number of parts of the entire valve, reducing the weight, and reducing the size and cost. Can be reduced.

  Further, as shown in FIG. 2, the composite valve 45 has a valve body 464 that opens and closes the valve seat 463 disposed at a position higher than the flow channel bottom surface of the introduction flow channel 462 and the flow channel bottom surface of the discharge flow channel 472. Therefore, even if water in the exhaust gas is accumulated in the valve bodies 461 and 471, it is provided so as not to be submerged. That is, the composite valve 45 has a countermeasure against freezing.

  Further, the on-off valve 46 includes the diaphragm D in order to prevent water from entering the space S in the driving portion of the plunger 466 through the gap between the plunger 466 and the guide member 468 in the outlet flow path 472. . Thus, by providing the diaphragm D between the plunger 466 that moves up and down and the guide member 468 that supports the plunger 466 so as to be able to advance and retreat, water is prevented from adhering to the drive portion of the plunger 466 and freezing. Therefore, it can be solved that the plunger 466 does not move due to freezing.

  In the flow rate adjusting valve 47, the needle valve body 473 is provided between the rotor 476 rotated by the step motor 474 and the needle valve body 473, and is moved up and down by a screw mechanism to adjust the opening degree of the valve body. For this reason, the flow rate adjusting valve 47 has a function of driving the needle valve body 473 with a relatively small torque of the step motor 474 even if the needle valve body 473 is frozen.

  In the above embodiment, the fuel cell system 1 for a vehicle has been described as an example. However, the present invention is not limited to this, and other fuel cell systems such as a ship and an aircraft may be used.

It is a block diagram which shows the structure of the fuel cell system which concerns on this embodiment. It is a figure which shows the modification of the fuel cell system which concerns on this embodiment, and is sectional drawing which shows the compound valve which integrated the on-off valve and the flow regulating valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell system 10 Fuel cell 10a Anode 10b Cathode 11 Fuel gas supply path 12 Oxidant gas supply path 14 Fuel gas circulation path 15 Fuel exhaust gas path 30 Scavenging means 40 Fuel exhaust gas dilution means 41 Purge means 42, 46 On-off valves 43, 47 Flow control valve 44 Diluter 45 Compound valve 60 Control device (control means)

Claims (4)

A fuel cell that generates electricity by reacting a fuel gas supplied to the anode and an oxidant gas supplied to the cathode; and
A fuel gas supply path for supplying the fuel gas to the anode;
An oxidant gas supply path for supplying an oxidant gas to the cathode;
A fuel gas circulation path for returning the fuel gas that has passed through the anode to the fuel gas supply path;
A fuel exhaust path for exhausting fuel exhaust gas from the anode;
At least purge means for purging the fuel exhaust gas from the fuel exhaust gas path, and scavenging means for introducing scavenging gas into the anode and scavenging residual gas in the anode and the fuel gas circulation path through the fuel exhaust gas path. On the other hand, in a fuel cell system comprising
An open / close controllable open / close valve and a flow rate adjustable valve arranged in series in the fuel exhaust gas path;
Control means for controlling at least one of a purge flow rate during purging by the purge means and a scavenging flow rate during scavenging by the scavenging means by controlling the on-off valve and the flow rate adjusting valve. A fuel cell system.   2. The fuel cell system according to claim 1, wherein the on-off valve is configured by a valve device that has taken measures against freezing and is disposed upstream of the flow rate adjustment valve.   The fuel cell system according to claim 1 or 2, wherein the on-off valve and the flow rate adjusting valve are integrally formed.   4. The control device according to claim 1, wherein when the fuel cell system is stopped, the control unit stops the fuel cell system after setting the flow rate adjusting valve to a purge flow rate that is performed at the next startup. The fuel cell system according to any one of claims.

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