JP2008218339A - Fuel cell system and dilution device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease fuel gas concentration in exhaust gas to a prescribed reference value or lower. <P>SOLUTION: A dilution device 50 is installed at meeting point A of an exhaust passage 37 through which fuel offgas is intermittently exhausted and an exhaust passage 23 of oxidative offgas, or its upstream side, and equipped with an expansion and contraction vessel 52 expanding or contracting the inner volume according to the gas pressure on the inside and an elastic body 53 installed adjacently to the expansion and contraction vessel 52, and the expansion and contraction vessel 52 has a fuel offgas introduction port 52a communicating with the upstream side of the exhaust passage 37 and a fuel offgas exhaust port 52b communicating with the downstream side of the exhaust passage 37 or an exhaust passage 23, and the elastic body 53 adds recovering force corresponding to the expansion of the inner volume of the expansion and contraction vessel 52 to the expansion and contraction vessel 52. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a diluter and a fuel cell system that reduce the concentration of fuel gas in exhaust gas discharged from a fuel cell.

  Currently, a fuel cell system including a fuel cell that receives a supply of reaction gas (fuel gas and oxidizing gas) and generates electric power has been proposed and put into practical use. Such a fuel cell system separates and recovers moisture generated during power generation from the reacted fuel gas (hydrogen offgas) discharged from the fuel cell, and purges the hydrogen offgas containing the recovered moisture and impurities to the outside. Perform the action. The hydrogen off gas discharged to the outside is intermittently released from the exhaust drain valve to the exhaust flow path side. This exhaust passage joins with the exhaust passage for oxidizing off-gas discharged from the fuel cell 10. Accordingly, the hydrogen off-gas is diluted with the oxidizing off-gas and is released into the atmosphere at a low concentration.

By the way, it is desirable that the hydrogen concentration in the exhaust gas discharged to the atmosphere is not more than a predetermined concentration. However, when hydrogen off-gas is intermittently released, the gas pressure of the hydrogen off-gas increases instantaneously at the start of intermittent discharge, and the oxidation off-gas Hydrogen off gas flows into the exhaust flow path at once. As a result, the hydrogen concentration of the exhaust gas released into the atmosphere increases or decreases at a timing corresponding to the timing of intermittent discharge, and the peak hydrogen concentration temporarily increases and may exceed the reference value. Therefore, in order to keep the hydrogen concentration in the exhaust gas released to the atmosphere below the reference value, a buffer tank is provided in the exhaust passage of hydrogen off gas, and the opening of the electromagnetic valve provided in this buffer tank is controlled to control the hydrogen off gas. There is one in which the hydrogen concentration of the exhaust gas after merging does not exceed a reference value by adjusting the release rate of the gas (see, for example, Patent Document 1).
JP 2005-347008 A

  In the configuration of Patent Document 1, the opening degree of the electromagnetic valve is controlled based on detected values such as the pressure and flow rate in the buffer tank, and the correlation between these detected values and the hydrogen concentration is stored in advance as data. It was necessary to accumulate data necessary for control, such as setting up. And if control data is inadequate, there existed a problem that hydrogen concentration could not be reliably made into a reference value or less. Further, the method of adjusting the opening of the electromagnetic valve based on the detection value of the sensor has a problem that the response to an instantaneous pressure increase due to intermittent discharge or the like is not sufficient.

  The present invention has been made in view of such circumstances, and suppresses an increase in the concentration of the fuel gas in the exhaust gas diluted by joining the exhaust gas containing the fuel gas that is intermittently released to the flow path of another gas. It is an object of the present invention to provide a fuel cell system and a diluter capable of performing the above.

  In order to achieve this object, a diluter according to the present invention includes a junction point between a first exhaust passage through which exhaust gas containing fuel gas is intermittently released and a second exhaust passage communicated with outside air, or the A diluter disposed on the upstream side, comprising: a telescopic container whose internal volume is expanded or contracted according to an internal gas pressure; and a restoring means disposed adjacent to the telescopic container, The telescopic container has a gas inlet communicating with the upstream side of the first exhaust flow path, and a gas outlet communicating with the downstream side of the first exhaust flow path or the second exhaust flow path. The restoring means applies a restoring force corresponding to the expansion of the internal volume of the expandable container to the expandable container.

  According to such a configuration, since the gas flow rate is mechanically adjusted by the expansion and contraction of the expansion and contraction container, an instantaneous pressure increase during the intermittent discharge of the exhaust gas is suppressed. Therefore, an increase in the concentration of fuel gas in the exhaust gas can be suppressed.

  Further, in the diluter of the present invention, the restoring means includes an elastic body disposed adjacent to the telescopic container, and a position regulating member that regulates movement of the elastic body and the telescopic container outside a predetermined region. The elastic body may be disposed so that the direction of the elastic force and the direction of expansion and contraction are substantially coincident.

  According to this configuration, the expansion and contraction container whose position is restricted by the position restriction member can be contracted using the elastic force of the elastic body. Therefore, the gas flow rate can be mechanically adjusted by the expansion and contraction of the expansion / contraction container, and an instantaneous pressure increase during the intermittent discharge of the exhaust gas is suppressed. Therefore, an increase in the concentration of the fuel gas in the exhaust gas is suppressed.

  In the diluter according to the present invention, the expandable container has a bellows-like tubular body and an end face that closes an end on one end thereof, and the gas inlet or the gas outlet is provided on the end face. The elastic body is disposed so as to abut against the end surface and the direction of the elastic force and the axial direction of the tubular body substantially coincide with each other, and the position restricting member includes the elastic container and the elastic body. A body that is housed therein, an opening through which the first exhaust passage on the upstream side connected to the gas inlet is inserted, and the downstream side connected to the gas outlet And an opening through which the first exhaust passage or the second exhaust passage is inserted.

  According to this configuration, the bellows-like tubular body disposed in the housing can be contracted using the elastic force of the elastic body. Therefore, the gas flow rate can be mechanically adjusted by the expansion and contraction of the tubular body, and an instantaneous pressure increase during intermittent discharge of exhaust gas is suppressed. Therefore, an increase in the concentration of the fuel gas in the exhaust gas is suppressed.

  The fuel cell system of the present invention includes a fuel cell that generates power by an electrochemical reaction between a fuel gas and an oxidizing gas, a first exhaust passage that intermittently discharges a fuel off-gas discharged from the fuel cell, and the fuel A diluter disposed on the upstream side or the second exhaust flow path for discharging the oxidizing off gas discharged from the battery to the outside, and the junction of the first exhaust flow path and the second exhaust flow path The diluter includes an extendable container whose internal volume is expanded or reduced according to an internal gas pressure, and a restoring means disposed adjacent to the expandable container. The expansion / contraction container is communicated with a gas inlet communicating with the upstream side of the first exhaust flow path and with the downstream side of the first exhaust flow path or the second exhaust flow path. A gas outlet, and the restoring means is an internal volume of the telescopic container. It is intended to apply a restoring force corresponding to the large to the expansion vessel.

  According to this configuration, when the fuel off-gas discharged from the fuel cell is intermittently released, the instantaneous pressure increase is suppressed, so that the concentration of the fuel gas in the exhaust gas discharged outside the fuel cell system is increased. It is possible to suppress the occurrence of a situation in which the fuel gas concentration of the exhaust gas exceeds a predetermined reference value.

  In this configuration, the restoring means is configured such that the fuel gas concentration in the mixed gas of the fuel off-gas discharged to the second exhaust passage and the oxidizing off-gas in the second exhaust passage is a predetermined reference value. The telescopic container may be contracted so that the fuel off-gas is released at a release rate as follows.

  According to the present invention, since the gas flow rate is mechanically adjusted by the expansion and contraction of the expansion and contraction container, an instantaneous pressure increase at the time of intermittent discharge of the exhaust gas is suppressed, and an increase in the concentration of the fuel gas in the exhaust gas is suppressed. .

  Hereinafter, a diluter according to an embodiment of the present invention and a fuel cell system 1 including the diluter will be described with reference to the drawings.

  FIG. 1 is a system configuration diagram of the fuel cell system 1. The fuel cell system 1 is used as an in-vehicle power generation system for fuel cell vehicles, a power generation system for any moving body such as a ship, an aircraft, a train, or a walking robot, and also as a power generation facility for buildings (housing, buildings, etc.). Although it can be applied to stationary power generation systems, it is specifically for automobiles.

  As shown in FIG. 1, the fuel cell system 1 according to the present embodiment includes a fuel cell 10 that generates electric power upon receiving a supply of reaction gas (oxidation gas and fuel gas), and the fuel cell 10 has an oxidant gas. Integrated control of the oxidizing gas piping system 2 as a gas flow path for supplying air, a hydrogen gas piping system 3 as a gas flow path for supplying hydrogen gas (anode gas) as a fuel gas to the fuel cell 10, and the entire system A control device 4 and the like are provided. Further, the fuel cell system 1 includes a hydrogen diluter 50 (diluter) provided in the vicinity of the merging point A (which may be the merging point A) of the exhaust gas flow path of the oxidizing gas piping system 2 and the hydrogen gas piping system 3. I have.

  The fuel cell 10 has a stack structure in which a required number of unit cells that generate power upon receiving a reaction gas are stacked. Here, the unit cell is of a solid polymer type, and is composed of an electrolyte membrane and a MEA (Membrane Electrode Assembly) composed of a pair of electrodes disposed on both surfaces thereof, and a pair of separators sandwiching the MEA. The electric power generated by the fuel cell 10 is supplied to a PCU (Power Control Unit) 11. The PCU 11 includes an inverter, a DC-DC converter, and the like that are disposed between the fuel cell 10 and the traction motor 12.

  The oxidizing gas piping system 2 includes an air supply passage 21 that supplies the fuel cell 10 with the oxidizing gas (air) humidified by the humidifier 20, and the air off-gas (oxidized off gas) discharged from the fuel cell 10 with the humidifier 20. And an exhaust passage 23 (second exhaust passage) for guiding the air off gas from the humidifier 20 to the outside (outside air). The air supply passage 21 is provided with a compressor 24 that takes in the oxidizing gas in the atmosphere and pumps it to the humidifier 20.

  The hydrogen gas piping system 3 includes a hydrogen tank 30 as a fuel supply source storing high-pressure (for example, 70 MPa) hydrogen gas, and hydrogen as a fuel supply passage for supplying the hydrogen gas from the hydrogen tank 30 to the fuel cell 10. A supply flow path 31 and a circulation flow path 32 as a return pipe for returning hydrogen off gas (fuel off gas) discharged from the fuel cell 10 to the hydrogen supply flow path 31 are provided.

  Instead of the hydrogen tank 30, a reformer that generates a hydrogen-rich reformed gas from a hydrocarbon-based fuel, a high-pressure gas tank that stores the reformed gas generated by the reformer in a high-pressure state, and Can also be employed as a fuel supply source. A tank having a hydrogen storage alloy may be employed as a fuel supply source.

  The hydrogen supply flow path 31 is provided with a shutoff valve 33 that shuts off or allows the supply of hydrogen gas from the hydrogen tank 30 and a regulator 34 that adjusts the pressure of the hydrogen gas. The regulator 34 is composed of a mechanical pressure reducing valve or the like. In addition, an electromagnetic drive type for controlling the gas flow rate and gas pressure supplied to the fuel cell 10 with higher accuracy by the control signal output from the control device 4 on the downstream side of the regulator 34 (fuel cell 10 side). An on-off valve may be provided.

  A discharge passage 37 (first exhaust passage) is connected to the circulation passage 32 via a gas-liquid separator 35 and an exhaust drain valve 36. The gas-liquid separator 35 separates and recovers moisture generated during power generation from the hydrogen off-gas discharged from the fuel cell 10. The exhaust / drain valve 36 discharges (purges) moisture collected by the gas-liquid separator 35 and hydrogen off-gas containing impurities in the circulation flow path 32 to the outside (outside air).

  The exhaust / drain valve 36 has electromagnetically driven opening / closing means such as an electromagnetic valve, for example, and operates according to a control signal from the control device 4. The exhaust / drain valve 36 intermittently discharges hydrogen off-gas to the discharge channel 37 side at a predetermined timing. The exhaust / drain valve 36 performs both exhaust and drainage. In order to exhaust the gas collected in the gas-liquid separator 35 to the outside and the gas in the circulation channel 32 to the outside. These exhaust valves may be provided separately, and these may be controlled separately by the control device 4.

  Further, the circulation channel 32 is provided with a hydrogen pump 38 that pressurizes the hydrogen off-gas after moisture recovery separated by the gas-liquid separator 35 and sends it to the hydrogen supply channel 31 side. The hydrogen off-gas transferred to the hydrogen supply channel 31 side by the hydrogen pump 38 is mixed with the hydrogen gas supplied from the hydrogen tank 30 side and circulated.

  The discharge passage 37 joins the exhaust passage 23 and communicates with the outside air downstream thereof. That is, the oxidizing gas piping system 2 and the hydrogen gas piping system 3 merge at the outlet side. Of the discharge channels 37, the discharge channel 37 on the side where the hydrogen off gas is discharged from the hydrogen diluter 50 has a smaller diameter than the discharge channel 37 on the side where the hydrogen off gas is introduced into the hydrogen diluter 50. .

  The air off-gas discharged from the oxidizing gas piping system 2 and the hydrogen off-gas discharged from the hydrogen gas piping system 3 are mixed at the junction A between the discharge flow path 37 and the exhaust flow path 23. As a result, the hydrogen off-gas containing high-concentration hydrogen is discharged outside the vehicle as a diluted gas (mixed gas) diluted to a predetermined hydrogen concentration or less by the air off-gas.

  The hydrogen diluter 50 is inserted in the vicinity of the confluence point A between the discharge flow path 37 and the exhaust flow path 23, more specifically, at a position immediately before the merge with the exhaust flow path 23 in the flow path of the discharge flow path 37. . The hydrogen off-gas discharged to the discharge passage 37 is diluted by joining with the air off-gas flowing through the exhaust passage 23 through the hydrogen diluter 50. The hydrogen concentration of the diluted gas after merging varies according to the relative inflow rates of the air off-gas and the hydrogen off-gas at the merging point A.

  Accordingly, the hydrogen diluter 50 is configured to have a function of decelerating the discharge speed of the hydrogen off-gas that is intermittently discharged from the discharge flow path 37 side into the exhaust flow path 23. This is to prevent the hydrogen concentration of the diluted gas after the merging from rapidly increasing by adjusting the release rate of the hydrogen off gas.

  FIG. 2 shows a cross-sectional configuration of the hydrogen diluter 50. As shown in this figure, the hydrogen diluter 50 includes a casing 51 (position regulating member, part of the restoring means) having a predetermined outer length along the hydrogen off-gas discharge direction (vertical direction in FIG. 2). ), And an expansion / contraction container 52 (extension / contraction container) and an elastic body 53 (elastic body, part of the restoring means) disposed inside the housing 51.

  The housing | casing 51 consists of a hollow cylindrical member, for example. In addition, the shape of the housing | casing 51 should just be a shape which can accommodate the expansion / contraction container 52 and the elastic body 53 in the inside so that it may mention later, and is not specifically limited. Moreover, the material of the housing | casing 51 should just have a predetermined intensity | strength like metal, resin, etc., and can hold | maintain the shape, and is not specifically limited.

  The casing 51 is arranged so that the end surface 51A on one end side in the axial direction (length direction) faces the upstream side of the discharge flow path 37, that is, the exhaust / drain valve 36 side. The end face 51A is provided with an upstream opening 51a through which the upstream discharge passage 37 can be inserted. Further, the end surface 51 </ b> B on the other end side of the casing 51 is disposed facing the downstream side of the discharge flow path 37, that is, the confluence point A side with the exhaust flow path 23. The end face 51B is provided with a downstream opening 51b through which the downstream discharge channel 37 can be inserted.

  The expandable container 52 is provided with end surfaces 52A and 52B at both ends of a flexible pipe (tubular body) 52C having a bellows-like tube wall, for example, to close the expandable container 52, and the end surfaces 52A and 52B have gas introduction ports and A gas discharge port is provided. Specifically, a bellows tube in which a metal thin plate is formed in a bellows shape, a resin bellows tube, and the like. The expandable container 52 is not limited to a shape like a bellows tube, as long as the internal volume can be changed according to the internal pressure at the time of gas introduction. For example, as a member whose internal volume can be changed in accordance with the expansion and contraction in the axial direction, a member in which the tube wall is formed of another stretchable material instead of the bellows-like tube wall can be considered. Moreover, although it does not expand-contract in the axial direction, it may be configured to be extendable in the radial direction or other directions. As the material of the expansion / contraction container 52, a material having low hydrogen gas permeability is used in order to reduce leakage of hydrogen off-gas introduced into the outside to the outside.

  The expandable container 52 is accommodated in the housing 51, and a hydrogen off-gas inlet 52 a (gas inlet) is provided on the end surface 52 </ b> A on one end side, and connected to the upstream side of the discharge channel 37. The end surface 52B on the other end side of the expandable container 52 is provided with a hydrogen off-gas discharge port 52b (gas outlet) and is connected to the downstream side of the discharge passage 37 (near the confluence point A with the exhaust passage 23). Has been. Note that the hydrogen off-gas discharge port 52b may be directly connected to the exhaust passage 23.

  The elastic body 53 is made of, for example, a helical spring. The elastic body 53 is accommodated in the housing 51 and is coaxially disposed adjacent to the expansion / contraction container 52 and its expansion / contraction direction. The elastic body 53 is arranged with one end abutting on the end surface 52A of the expandable container 52 and the other end abutting on the inner wall of the casing 51. That is, the elastic body 53 is disposed so that the expansion / contraction direction of the elastic body 53 and the expansion / contraction direction of the expansion / contraction container 52 coincide. In FIG. 2, an upstream exhaust passage 37 inserted into the housing 51 from the upstream opening 51 a is inserted through the center of the helical spring-like elastic body 53.

  In addition, the elastic body 53 may be arrange | positioned adjacent to the downstream rather than the upstream of the expansion-contraction container 52. FIG. The elastic body 53 may be a spring having another shape such as a leaf spring. A plurality of springs may be used in parallel. Moreover, elastic bodies other than a spring may be sufficient. The point is that the elastic body 53 can provide a restoring force in the direction of returning to the original shape, that is, a compressive force, to the expandable container 52 whose internal volume is expanded by the internal pressure at the time of gas introduction. Good. For example, in the helical spring-like elastic body 53 shown in FIG. 2, the expansion / contraction direction of the bellows tubular expansion / contraction container 52 and the expansion / contraction direction of the spring are aligned and adjacent to each other. The elastic body 53 whose position is regulated by the casing 51 is compressed according to the expansion (internal volume expansion) of the expansion / contraction container 52, and the elastic force of the compressed elastic body 53 compresses the expansion / contraction container 52. A restoring force (compression force) in a direction to restore the original length acts on the end face 52A.

  Therefore, when the expandable container 52 is configured to be expandable / contractible in the radial direction or other directions as described above, the elastic body 53 is disposed adjacent to the radial direction, which is the expansion / contraction direction, and these are arranged in a predetermined manner. If it is accommodated in the casing 51 so as to be accommodated within the dimensions, similarly, when the internal volume of the expandable container 52 is expanded, it can be configured such that a restoring force acts against the internal pressure.

  The control device 4 detects an operation amount of an acceleration operation device (accelerator or the like) provided in the vehicle, receives control information such as an acceleration request value (for example, a required power generation amount from a load device such as the traction motor 12), Control the operation of various devices in the system. Further, the control device 4 drives and controls the compressor 24, the shut-off valve 33, and the regulator 34 to supply gas (oxidizing gas and hydrogen gas) into the fuel cell 10, as well as an exhaust drain valve 36, a hydrogen pump 38, and the like. Drive control is performed to perform purge operation and circulation of hydrogen off-gas from the circulation flow path 32.

  During normal operation of the fuel cell system 1, hydrogen gas is supplied from the hydrogen tank 30 to the anode electrode of the fuel cell 10 through the hydrogen supply channel 31, and the air that has been subjected to humidification adjustment passes through the air supply channel 21. Then, power is generated by being supplied to the cathode electrode of the fuel cell 10. At this time, the power (required power) to be drawn from the fuel cell 10 is calculated by the control device 4, and hydrogen gas and air in an amount corresponding to the amount of power generation are supplied into the fuel cell 10. Further, in the purge operation, the hydrogen off gas is intermittently released to the discharge flow path 37 side at a predetermined timing.

  The control device 4 is configured by a computer system (not shown). Such a computer system includes a CPU, ROM, RAM, HDD, input / output interface, display, and the like, and various control operations are realized by the CPU reading and executing various control programs recorded in the ROM. It is like that.

  Here, based on FIG. 3, the operation of the hydrogen diluter 50 when the hydrogen offgas intermittently released to the discharge channel 37 side is merged with the air offgas in the exhaust channel 23 will be described.

  As described above, the hydrogen diluter 50 has a configuration in which a restoring force that reduces the internal volume in accordance with the expansion of the internal volume of the expansion / contraction container 52 works. Therefore, in a steady state, the gas pressure and the elastic force of the elastic body 53 are used. Are in a balanced state. Therefore, in a state where the downstream side of the expansion / contraction container 52 is opened to the exhaust flow path 23, the gas pressure in the expansion / contraction container 52 and the gas pressure of the dilution gas in the exhaust flow path 23 become the same, and the elastic body 53 The length is balanced (Fig. 3a).

  When the hydrogen off-gas during intermittent discharge flowing through the upstream discharge passage 37 flows into the expansion / contraction container 52 at a high speed from the hydrogen off-gas introduction port 52a, the expansion / contraction container 52 is rapidly expanded according to the inflow gas pressure, and the internal volume is increased. Is enlarged. Thereby, the end surface 52A on the upstream side of the expandable container 52 moves in the extending direction, and the elastic body 53 whose position is regulated by the inner wall of the casing 51 is compressed (FIG. 3b). The gas pressure in the expansion / contraction container 52 at each time after the start of the intermittent discharge gas inflow corresponds to the restoring force of the elastic body 53. Therefore, the outflow speed of the hydrogen off gas released from the hydrogen off gas discharge port 52b to the discharge flow path 23 side after the start of the intermittent discharge gas inflow does not increase rapidly but increases according to the compression of the elastic body 53. In addition, the gas pressure at the peak time in the expandable container 52 is lower than the gas pressure of the intermittently released gas that has flowed through the upstream discharge passage 37.

  Subsequently, when the inflow of the intermittently released hydrogen off gas stops, the elastic container 53 contracts due to the restoring force of the elastic body 53 to reduce the internal volume, and accordingly, the hydrogen off gas is gradually released to the discharge flow path 23 side. (FIG. 3c). The release of the hydrogen off-gas ends when the elastic body 53 has a natural length and the gas pressure in the expansion / contraction container 52 and the gas pressure of the dilution gas in the exhaust passage 23 become the same.

  With such a configuration, even if there is a sudden release of hydrogen off-gas from the exhaust / drain valve 36, the released gas is temporarily stored in the expansion / contraction container 52 and suddenly released to the discharge flow path 23 side. Not. Therefore, since the speed of the hydrogen off gas at the time of merging with the air off gas flowing in the exhaust flow path 23 is decreased, the hydrogen concentration of the merged dilution gas does not increase rapidly. Therefore, the concentration of the dilution gas discharged to the outside of the vehicle can be prevented from exceeding a predetermined concentration.

  In the above embodiment, the expansion / contraction container 52 capable of increasing / decreasing the internal volume is provided inside the casing 51. However, the inside of the casing 51 is partitioned into two spaces by a partition plate, and this partition plate is The inside of the housing 51 is configured to be movable while maintaining an airtight state, and one end of an elastic material such as a spring is attached to the partition plate, and the other end of the elastic material is attached to the inner wall of the housing 51. Also good.

  In such a configuration, if an inlet that allows intermittently released gas to flow into a space that is not provided with an elastic material in a space partitioned into two and an outlet to the exhaust passage 23 side are provided, Similar to the embodiment, the instantaneous pressure increase during the intermittent discharge of the exhaust gas is suppressed by the expansion of the internal volume based on the movement of the partition plate.

It is a block diagram of a fuel cell system. It is sectional drawing of the hydrogen diluter which concerns on embodiment of this invention. It is sectional drawing which shows operation | movement of a hydrogen diluter.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 4 ... Control apparatus, 10 ... Fuel cell, 23 ... Exhaust flow path (2nd exhaust flow path), 36 ... Exhaust drain valve, 37 ... Discharge flow path (1st exhaust flow path), DESCRIPTION OF SYMBOLS 50 ... Hydrogen diluter (diluter), 51 ... Housing | casing (position control member, a part of decompression | restoration means), 52 ... Expansion-contraction container, 52a ... Hydrogen off gas inlet (gas inlet), 52b ... Hydrogen off gas discharge port ( Gas outlet), 53 .. Elastic body (part of restoring means)

Claims (5)

A diluter disposed at the junction or upstream of a first exhaust passage through which exhaust gas containing fuel gas is intermittently released and a second exhaust passage communicated with outside air,
An extendable container whose internal volume is expanded or reduced according to the internal gas pressure, and a restoring means disposed adjacent to the expandable container,
The telescopic container has a gas inlet communicating with the upstream side of the first exhaust flow path, and a gas outlet communicating with the downstream side of the first exhaust flow path or the second exhaust flow path. Have
The diluting device, wherein the restoring means applies a restoring force corresponding to the expansion of the internal volume of the telescopic container to the telescopic container. The restoring means includes an elastic body disposed adjacent to the telescopic container, and a position regulating member that regulates movement of the elastic body and the telescopic container outside a predetermined region,
The diluter according to claim 1, wherein the elastic body is disposed so that an action direction of the elastic force and the expansion / contraction direction substantially coincide with each other. The expandable container has a bellows-like tubular body and an end face that closes an end on one end thereof, and the gas inlet or the gas outlet is provided on the end face,
The elastic body is disposed so as to abut against the end surface, and the direction in which the elastic force acts and the axial direction of the tubular body substantially coincide with each other.
The position restricting member comprises a housing in which the expandable container and the elastic body are accommodated, and an opening through which the first exhaust passage on the upstream side connected to the gas inlet is inserted, The diluter according to claim 2, further comprising: an opening through which the first exhaust passage or the second exhaust passage on the downstream side connected to the gas outlet is inserted. A fuel cell that generates electricity by an electrochemical reaction between a fuel gas and an oxidizing gas, a first exhaust passage that intermittently discharges a fuel off-gas discharged from the fuel cell to the outside, and an oxidizing off-gas discharged from the fuel cell. A fuel cell system comprising: a second exhaust passage that discharges to the outside; and a diluter that is disposed on the upstream side or the junction of the first exhaust passage and the second exhaust passage. Because
The diluter comprises an extendable container whose internal volume is expanded or reduced in accordance with an internal gas pressure, and a restoring means disposed adjacent to the expandable container,
The telescopic container includes a gas inlet connected to the upstream side of the first exhaust flow path, and a gas outlet connected to the downstream side of the first exhaust flow path or the second exhaust flow path. Have
The fuel cell system, wherein the restoring means applies a restoring force corresponding to the expansion of the internal volume of the telescopic container to the telescopic container.   The restoring means is configured so that a fuel gas concentration in a mixed gas of the fuel off-gas released to the second exhaust passage side and the oxidizing off-gas in the second exhaust passage is equal to or lower than a predetermined reference value. The fuel cell system according to claim 4, wherein the telescopic container is contracted so as to release the fuel off-gas at a high release rate.

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