JP2008226513A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system whereof a lifetime is improved and good power generating performance is secured for a long period of time, and operation is made possible even when a valve becomes out of order. <P>SOLUTION: This fuel cell system is equipped with an entrance shut valve 20 provided in a main route 30 forming an oxidation gas supply passage 14, a humidifier bypass valve 18 provided in a humidifier bypass route 32 forming the bypass of the main route 30, and a control part. The control part cuts off the gas upstream side of the passage on the cathode side electrode side of a fuel cell stack 12 by cutting off both of the entrance shut valve 20 and the humidifier bypass valve 18, when the fuel cell stack 12 stops generating power. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell system including a fuel cell that generates electric power by an electrochemical reaction between a fuel gas and an oxidizing gas.

  The fuel cell system includes a fuel cell that generates electric power by an electrochemical reaction of a reaction gas between a fuel gas and an oxidizing gas, a reaction gas supply channel for supplying the reaction gas to the fuel cell, and discharges the reaction gas from the fuel cell. And a reaction gas system discharge flow path. It is also considered to provide a fuel cell shut-off valve in such a reactive gas supply channel and a reactive gas system discharge channel.

  For example, a fuel cell system described in Patent Document 1 includes a shutoff valve provided in a reaction gas system discharge passage for discharging a reaction gas system gas from a fuel cell stack, and a fuel gas supply for supplying fuel gas to the fuel cell stack Air is supplied through an accumulator to the three-way switching valve provided in the flow path and the valve provided in the oxidizing gas system supply flow path for supplying air to the fuel cell stack, and the pilot valves are switched. ing.

  Further, in the case of the fuel cell system described in Patent Document 2, two flow paths arranged in parallel with respect to the gas flow in the fuel gas supply flow path for supplying fuel gas to the fuel cell main body, and two flow paths And a flow control valve provided in the passage. In addition, the ECU controls the flow rate control valve, and activates only the other with one being closed to detect a failure of the flow rate control valve. And when the flow rate measured at the time of operation of the flow control valve is larger than the specified value, it is determined that the other flow control valve is in a state of opening, and when it is smaller than the specified value, It is determined that the other flow rate control valve is malfunctioning in the closed state. If it is determined that one of the flow control valves is malfunctioning in the open state, a part of the power corresponding to the leakage generation amount is used for charging the secondary battery, and the rest is supplied to the load. . If it is determined that one of the flow control valves is in a closed state, the normal valve is controlled to the required gas amount when the maximum control flow rate of the normal valve is less than the required gas amount. At the same time, the ECU supplies insufficient power from the secondary battery to the load.

  In the case of the fuel cell system described in Patent Document 3, the oxidizing gas supply channel for supplying the oxidizing gas to the fuel cell includes a main path that passes through the humidifier and a humidifier bypass path that bypasses the humidifier. Prepare. Each of the main path and the humidifier bypass path is provided with an MFC or an electric valve that automatically controls the mass flow rate of the gas in accordance with a flow rate setting signal given from the outside. Patent Document 3 does not disclose that the main path and the humidifier bypass path are shut off by an MFC or a motor-operated valve when stopped.

Japanese Patent Laid-Open No. 2000-3717 JP 2005-302563 A JP 7-235324 A

  In the case of the fuel cell system described in Patent Document 1, air from the air compressor is supplied to the cell stack through a single path that does not branch in parallel with respect to the gas flow. In addition, the air-based gas is discharged from the battery stack through a single path that does not branch in parallel with respect to the gas flow. Further, the fuel cell system is provided with an oxidizing gas supply channel for supplying air to the battery stack and an oxidizing gas system discharging channel for discharging air-based gas from the battery stack, and the oxidizing gas supply channel and the oxidizing gas system discharge are provided. A valve and a shut-off valve are provided in the flow path. For this reason, when a valve or shut-off valve is used in a low-temperature environment such as below freezing, etc., the periphery of the valve body is fixed due to freezing, etc. It becomes difficult to discharge air-based gas. In this case, the operation of the fuel cell system is automatically stopped due to the failure of the shutoff valve.

  Further, when the valve provided in the oxidizing gas supply channel or the oxidizing gas system discharge channel or the shutoff valve is opened when the fuel cell system is stopped, the catalyst provided in the battery stack is held by carbon. Carbon may oxidize early and the fuel cell system may reach the end of its life or the power generation performance of the battery stack may be reduced.

  On the other hand, in the case of the fuel cell system described in Patent Document 2, in the fuel gas supply channel for supplying the fuel gas to the fuel cell main body, two channels arranged in parallel with respect to the gas flow, The flow rate control valve is provided in two flow paths, but it is not disclosed to provide two flow paths in parallel with respect to the gas flow in the oxidizing gas supply flow path or the oxidizing gas system discharge flow path. . For this reason, the operation of the fuel cell system is automatically stopped when a valve provided in the oxidizing gas supply channel or the oxidizing gas system discharge channel fails. In addition, when new air is supplied to the fuel cell main body through the oxidizing gas supply flow path when the operation is stopped, the carbon is oxidized early when the catalyst constituting the fuel cell main body is held by carbon, and the fuel is The battery system may reach the end of its life early, or the power generation performance of the fuel cell may be reduced.

  Further, in the case of the fuel cell system described in Patent Document 3, the oxidizing gas supply flow path includes a main path and a humidifier bypass path, and a valve is provided in each of the main path and the humidifier bypass path. However, it is not considered to improve the life of the system by devising the open / close state of each valve when the system is stopped. Further, it is not considered that the fuel cell system can be operated even when any of the valves provided in the main path and the humidifier bypass path fails.

  An object of the present invention is to improve the lifetime of a fuel cell system, to ensure good power generation performance over a long period of time, and to enable operation even when a valve fails.

  A fuel cell system according to the present invention is a fuel cell system comprising a fuel cell that generates electricity by an electrochemical reaction between a fuel gas and an oxidizing gas, and an oxidizing gas passage for supplying or discharging the oxidizing gas to the fuel cell. A first shut-off valve provided in the first gas flow path constituting the oxidizing gas flow path, and a second gas flow path provided in the second gas flow path that is a detour of the first gas flow path. And a control part, and the control part shuts off both the first shut-off valve and the second shut-off valve when power generation of the fuel cell is stopped, so that the cathode side electrode side of the fuel cell The fuel cell system is characterized in that the upstream side or the downstream side of the gas in the flow path is cut off.

  Preferably, one of the first shut-off valve and the second shut-off valve is a normally closed shut-off that is closed in a normal state in which all the pressure chambers are at the same pressure. The other shut-off valve is a normally open shut-off valve that is open in the normal state.

  More preferably, the oxidizing gas channel is an oxidizing gas supply channel for supplying oxidizing gas to the fuel cell, the first gas channel is a main channel passing through the humidifier, and the second gas channel is The path is a humidifier bypass path that bypasses the humidifier, and the first shut-off valve is a normally open type inlet shut-off valve that opens in the normal state where all the internal pressure chambers are at the same pressure. The shutoff valve 2 is a normally closed humidifier bypass valve that is closed in the normal state.

  More preferably, the first shut-off valve and the second shut-off valve are valves driven by a pressure difference between fluids, and the other of the normally open type of the first shut-off valve and the second shut-off valve is used. A pressure control flow path for supplying a fluid for generating a pressure difference to the shut-off valve, and a normally closed electromagnetic that shuts off the flow path when not in operation, used to maintain the pressure in the pressure control flow path The normally closed solenoid valve maintains the pressure in the pressure control flow path when the fuel cell stops generating power, thereby closing the other normally open shutoff valve.

  More preferably, when the control unit detects that an abnormality has occurred in one of the first shut-off valve and the second shut-off valve at the time of start-up, the control unit turns on the other shut-off valve. The valve is opened, and the oxidizing gas is supplied to the fuel cell through the flow path provided with the other shut-off valve.

  More preferably, the control unit detects an abnormality of one of the shutoff valves from a pressure value detected by the pressure detection means or a situation of an electromagnetic valve provided to drive the shutoff valve.

  More preferably, the oxidizing gas channel is an oxidizing gas supply channel for supplying oxidizing gas to the fuel cell, the first channel is a main channel that passes through the humidifier, and the second channel is A humidifier bypass path that bypasses the humidifier is provided, and the controller is configured to provide a second shut-off valve provided in the humidifier bypass path during a scavenging process for supplying an oxidizing gas to the fuel cell after receiving a power generation stop command for the fuel cell. Scavenging process control means for supplying an oxidizing gas to the fuel cell through a first shut-off valve provided in this path when is not opened.

  According to the fuel cell system of the present invention, the first shutoff valve provided in the first gas flow path that constitutes the oxidizing gas flow path, and the second gas that is a detour of the first gas flow path. A second shutoff valve provided in the flow path, and a control unit, wherein the control unit shuts off both the first shutoff valve and the second shutoff valve when power generation of the fuel cell is stopped. Since the gas upstream side or downstream side of the flow path on the cathode side electrode side of the fuel cell is shut off, even when the catalyst provided in the fuel cell is held by carbon, new air is introduced into the fuel cell during operation stoppage. It can be made difficult to be introduced, and the early oxidation of carbon can be suppressed. For this reason, the lifetime of the fuel cell system can be improved, and good power generation performance can be secured for a long time. Further, by using one of the first shut-off valve and the second shut-off valve when one of the valves fails, the fuel cell system can be operated. For example, even when the first shut-off valve fails in the closed state, by opening the second shut-off valve, new gas can be supplied to the fuel cell, and the fuel cell can be generated.

  The oxidizing gas channel is an oxidizing gas supply channel for supplying oxidizing gas to the fuel cell, the first gas channel is a main channel passing through the humidifier, and the second gas channel is a humidifier. The first shut-off valve is a normally open type inlet shut-off valve that opens in the normal state in which all the pressure chambers are at the same pressure, and the second shut-off valve According to the configuration of the normally closed humidifier bypass valve that is closed in the normal state, the inlet shut-off valve is opened even when the solenoid valve for controlling the pressure in the pressure chamber of the inlet shut-off valve fails. The valve state can be easily achieved, and the fuel cell system can be prevented from being stopped due to an abnormal increase in pressure in the flow path. In addition, since the humidifier bypass valve is normally closed, the humidifier bypass valve can be kept closed even when a solenoid valve for controlling the pressure in the pressure chamber of the humidifier bypass valve fails. Air that is excessively dry during the operation of the system is introduced into the fuel cell, and it is possible to prevent power generation performance from being deteriorated due to insufficient humidification inside the fuel cell.

  On the other hand, in the case of the configuration conventionally considered, the humidifier bypass valve corresponding to the second cutoff valve provided in the humidifier bypass path that bypasses the humidifier has a gas cutoff function in the flow path. The use of valves was not considered. For example, it has been considered to use a butterfly valve as a humidifier bypass valve. On the other hand, by using a humidifier bypass valve having a gas shut-off function, it is difficult to introduce new air into the fuel cell more effectively during operation stop.

  Further, one of the first shut-off valve and the second shut-off valve is a normally closed shut-off valve that is closed in a normal state in which all the pressure chambers are at the same pressure, In the configuration in which the other shut-off valve is a normally open shut-off valve that is opened in the normal state, the first shut-off valve and the second shut-off valve are valves driven by a fluid pressure difference, A pressure control flow path for supplying a fluid for generating a pressure difference to the other normally open shut-off valve of the first shut-off valve and the second shut-off valve; and a pressure in the pressure control flow path And a normally closed solenoid valve that is used to maintain and shuts off the flow path when not in operation, and the normally closed solenoid valve maintains the pressure in the pressure control flow path when the power generation of the fuel cell is stopped. The other of the normally open type According to the configuration of the cross-sectional valve in a closed state, the power to continue blocking the normally open type of the other shut-off valve in the power generation stop is not required, thereby the fuel efficiency.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 5 show a first embodiment of the present invention, and FIG. 1 is a schematic configuration diagram of a fuel cell system according to the present embodiment. The fuel cell system 10 includes a fuel cell stack 12, an oxidizing gas supply channel 14 and an oxidizing gas system discharge channel 16, a humidifier bypass valve 18 that is a second cutoff valve, and an inlet that is a first cutoff valve. A shut valve 20 and an outlet shut valve 22 are provided.

  The fuel cell stack 12 generates power by an electrochemical reaction between oxygen and hydrogen. That is, by supplying hydrogen gas, which is a fuel gas, and air, which is an oxidizing gas, to the fuel cell stack 12, oxygen and hydrogen react in an electrochemical reaction in a plurality of fuel cells not shown in the fuel cell stack 12. Electric energy can be obtained. The fuel cell includes, for example, a membrane-electrode assembly in which an electrolyte membrane is sandwiched between an anode side electrode and a cathode side electrode, and separators on both sides thereof.

  In addition, the fuel cell system 10 of this embodiment is mounted in a vehicle for, for example, a fuel cell vehicle, and the fuel cell stack 12 is used as a power source for a vehicle driving motor. Of course, the fuel cell system of the present embodiment can also be used for purposes other than vehicle driving.

  An oxidizing gas supply channel 14 is provided to supply air, which is an oxidizing gas, to the fuel cell stack 12. An air compressor 24 and an intercooler 26 are provided on the gas upstream side of the oxidizing gas supply channel 14. The air pressurized by the air compressor 24 is cooled by the intercooler 26, humidified by the humidifier 28, and then supplied to the channel on the cathode side electrode side of the fuel cell stack 12.

  In addition to the main path 30 which is a first gas flow path for supplying air to the fuel cell stack 12 after passing through the humidifier 28, the second path 30 and the gas flow are in parallel with each other. The humidifier bypass path 32, which is a bypass of the main path 30, is provided. The air passing through the humidifier bypass path 32 is supplied to the fuel cell stack 12 without passing through the humidifier 28. A humidifier bypass valve 18 is provided in the middle of the humidifier bypass path 32.

  In addition, an oxidizing gas discharge channel 16 is provided to discharge air off-gas, which is air supplied to the fuel cell stack 12 and subjected to an electrochemical reaction in each fuel cell, from the fuel cell stack 12. ing. The air off-gas discharged through the oxidizing gas system discharge flow channel 16 is sent to the humidifier 28 via the pressure regulating valve 34 and then released to the atmosphere via a diluter (not shown). The pressure regulating valve 34 is controlled so that the pressure (back pressure) of the air discharged from the fuel cell stack 12 becomes an appropriate pressure value according to the operating state of the fuel cell stack 12. That is, the pressure of the air corresponding to the position of the pressure sensor P2 in the oxidizing gas discharge channel 16 is adjusted by the valve opening degree of the pressure regulating valve 34. Further, the humidifier 28 serves to humidify the moisture obtained from the air discharged from the fuel cell stack 12 to the air before being supplied to the fuel cell stack 12.

  The fuel cell stack 12 is connected with a hydrogen gas supply channel for supplying hydrogen gas and a hydrogen gas system discharge channel for discharging hydrogen gas system gas. Omitted.

  Further, in the main path 30 of the oxidizing gas supply flow path 14, between the upstream side connection portion of the humidifier bypass path 32 and the humidifier 28, and in the oxidizing gas system discharge flow path 16, the gas downstream of the humidifier 28. A fuel cell bypass path 36 is connected between the sides so as to be parallel to the fuel cell stack 12 with respect to the gas flow. A fuel cell bypass valve 38 is provided in the middle of the fuel cell bypass path 36. The fuel cell bypass valve 38 is used to control the pressure of air supplied to the fuel cell stack 12. That is, the pressure of the air corresponding to the position of the inlet pressure sensor P1 of the oxidizing gas supply flow path 14 is adjusted by the valve opening degree of the fuel cell bypass valve 38. The air pressure corresponding to the position of the inlet pressure sensor P1 can also be adjusted by the flow rate of the air discharged from the air compressor 24. Of course, the air pressure corresponding to the position of the inlet pressure sensor P1 can be adjusted by using both the valve opening of the fuel cell bypass valve 38 and the discharge flow rate of the air compressor 24.

  In addition, the fuel cell system 10 preferably raises the temperature of the fuel cell stack 12 quickly at a low temperature start such as below freezing. For this reason, compared to the amount of hydrogen gas supplied to the fuel cell stack 12, the amount of air supplied to the fuel cell stack 12 is less than the amount commensurate with power generation by reaction with hydrogen gas. That is, it is conceivable that the cathode stoichiometric ratio is lowered to generate power with low efficiency, and the temperature of the fuel cell stack 12 is rapidly increased. However, in this case, hydrogen may enter the cathode-side channel from the anode-side channel of the fuel cell stack 12 through the electrolyte membrane, and the hydrogen concentration in the oxidizing gas discharge channel 16 may increase. is there. In such a case, the fuel cell bypass valve 38 can be used to reduce the hydrogen concentration in the oxidizing gas system discharge flow path 16 by the air that does not pass through the fuel cell stack 12 in such a case. .

  Further, the inlet shut valve 20 and the outlet shut are respectively provided on the gas downstream side of the humidifier 28 of the main path 30 of the oxidizing gas supply flow path 14 and the gas upstream side of the humidifier 28 of the oxidizing gas system discharge flow path 16. A valve 22 is provided.

  That is, each of the inlet shut valve 20 and the outlet shut valve 22, which is a fuel cell valve and a fluid control valve for adjusting the flow of air in the flow path, and the humidifier bypass valve 18 described above, Three PSVs (Pressure Switching Valves), each of which is a normally closed solenoid valve, are connected via the pressure control flow path 40.

  That is, three PSVs VbS, VbC, and VbO are connected to the humidifier bypass valve 18. In addition, three PSVs ViS, ViC, and ViO are connected to the inlet shut valve 20, and three PSVs, VoS, VoC, and VoO, are connected to the outlet shut valve 22. These PSVs are connected to the upstream side of the main passage 30 of the oxidizing gas supply passage 14 via the pressure control passage 40, for example, between the air compressor 24 and the humidifier 28. All these PSVs, VbS, VbC, VbO, ViS, ViC, ViO, VoS, VoC, and VoO, are controlled by a control unit such as an ECU (Electronic Control Unit) (not shown). The humidifier bypass valve 18, the inlet shut-off valve 20, and the outlet shut-off valve 22 are all driven by a gas pressure difference that is a fluid existing in the internal pressure chamber. The pressure control flow path 40 supplies gas, which is a fluid for generating a pressure difference, to the valves 18, 20, and 22.

  Next, with reference to FIGS. 2 and 3, the configuration and operation of the inlet shut valve 20 and the outlet shut valve 22 will be described mainly using the inlet shut valve 20 as a representative. The configuration itself of the inlet shut valve 20 and the outlet shut valve 22 is the same. The configuration of the humidifier bypass valve 18 will be described later.

  As shown in FIG. 2, the inlet shut valve 20 is a normally open shut valve in which the valve element is opened in a normal state in which all the pressure chambers provided therein have the same pressure.

  The inlet shut valve 20 is provided with two upper and lower spaces partitioned by a partition portion 44 inside a housing 42 formed by coupling a plurality of housing elements. A main diaphragm 46 and a sub diaphragm 48 are respectively provided in the two spaces. Are provided, the valve closing pressure chamber 50 on the upper surface side of the main diaphragm 46, the valve opening pressure chamber 52 on the lower surface side, the atmospheric pressure chamber 54 on the upper surface side of the sub diaphragm 48, and the lower surface side. Each of the flow path constituting pressure chambers 56 is provided. The valve closing pressure chamber 50, the valve opening pressure chamber 52, the atmospheric pressure chamber 54, and the flow path constituting pressure chamber 56 are separated from each other, and any two of these pressure chambers 50, 52, 54, 56 are separated. The pressure chambers are not in communication with each other.

  Further, the main diaphragm 46 and the sub diaphragm 48 are coupled to the valve body 58. That is, the valve body 58 having the drive shaft 60 is provided inside the housing 42, and the valve body 58 is supported on the housing 42 so as to be displaceable in the axial direction of the drive shaft 60. The valve body 58 includes a drive shaft 60 and a disc-shaped valve body main body 62 coupled to the lower end portion of the drive shaft 60. Further, a cylindrical member 64 having a bottomed cylindrical shape having a drive shaft side cylindrical surface portion 63 on the outer peripheral surface is coupled near the lower end of the intermediate portion of the drive shaft 60.

  Further, the inner peripheral side end portion of the sub diaphragm 48 made of an elastic material such as rubber is sandwiched between the bottom surface of the bottom plate portion of the cylindrical member 64 and the upper surface of the valve body 62, and the inner peripheral portion of the sub diaphragm 48 Are coupled to the drive shaft 60. The outer peripheral side end of the sub diaphragm 48 is coupled to the inner peripheral portion of the housing 42 so as to be sandwiched by two housing elements constituting the housing 42. Thereby, the upper side and the lower side of the space below the partition portion 44 in the housing 42 are separated into the atmospheric pressure chamber 54 and the flow path constituting pressure chamber 56 by the sub diaphragm 48.

  In addition, a diaphragm side cylindrical portion 66 that is elastically deformed so as to be pressed along the drive shaft side cylindrical surface portion 63 is provided near the inner diameter in the radial direction of the sub diaphragm 48. Then, from the valve closed state as shown in FIG. 3, the sub-diaphragm 48 is deformed into an upward mountain-shaped annular shape that exists between the drive shaft side cylindrical surface portion 63 of the cylindrical member 64 and the inner surface of the housing 42. The lower surface of the annular deformation portion 67 is adapted to receive the pressure of the flow path constituting pressure chamber 56. Then, when the lower surface of the annular deformation portion 67 receives the pressure of the flow path constituting pressure chamber 56, the upper portion of the diaphragm side cylindrical portion 66 is elastically deformed so as to be peeled off from the drive shaft side cylindrical surface portion 63 as shown in FIG. However, the drive shaft 60 is displaced upward.

  Further, a second diaphragm side cylindrical portion 70 that is elastically deformed so as to be pressed along the housing side cylindrical surface portion 68 provided on the inner surface of the housing 42 is provided near the outer diameter in the radial direction middle portion of the sub diaphragm 48. 2, when the drive shaft 60 is displaced downward as shown in FIG. 3 from the open state as shown in FIG. 2, the upper part of the second diaphragm side cylindrical portion 70 is elastically peeled off from the housing side cylindrical surface portion 68. I am trying to transform.

  The flow path constituting pressure chamber 56 constitutes a part of the oxidizing gas supply flow path 14 (see FIG. 1) (in the case of the outlet shut valve 22, the oxidizing gas system discharge flow path 16). The gas downstream side is cut off or connected. The atmospheric pressure chamber 54 is connected to an atmospheric communication pipe 72 having one end communicating with the atmosphere, and the atmospheric pressure chamber 54 is opened to the atmosphere.

  Further, a restraining member 74 formed by joining two substantially disk-shaped elements is coupled to the upper end portion of the valve body 58, and an elastic material such as rubber is formed between the two substantially disk-shaped elements. The inner peripheral side end of the main diaphragm 46 is pinched. The outer peripheral side end portion of the main diaphragm 46 is coupled to the inner peripheral portion of the housing 42 so as to be sandwiched by two housing elements constituting the housing 42. Thus, the upper side and the lower side of the space above the partition 44 in the housing 42 are separated into the valve closing pressure chamber 50 and the valve opening pressure chamber 52 by the main diaphragm 46. A supply / exhaust pipe 76 is connected to the valve closing pressure chamber 50 and the valve opening pressure chamber 52.

  Further, a coil spring 78 as an elastic force imparting means is provided between the lower surface of the holding member 74 and the upper surface of the partition portion 44, and the elastic force is applied to the valve body 58 in the upward direction, that is, in the direction in which the valve is opened. is doing. When the valve body 58 is displaced downward, the lower surface of the valve body main body 62 is seated on the valve seat 80 to block the flow path. That is, the inside of the flow path is blocked or connected by the axial displacement of the drive shaft 60. Further, the diameter of the pressure receiving area of the upper part of the drive shaft 60 including the main diaphragm 46 is sufficiently larger than the diameter of the pressure receiving area of the lower part of the drive shaft 60 including the sub diaphragm 48.

  In such an inlet shut valve 20, the valve closing pressure chamber 50 is connected to the pressure control flow path 40 on the ViC side, which is PSV, via a supply / discharge pipe 76 (FIGS. 2 and 3). The valve-opening pressure chamber 52 is connected to the pressure control flow path 40 on the ViO side, which is PSV, via a supply / discharge pipe 76. Due to the displacement of the drive shaft 60 in the axial direction, the central portion of the main diaphragm 46 is displaced so as to warp up and down.

  As shown in FIG. 2, when the valve body 58 is driven upward by the displacement of the drive shaft 60, the air flowing from the upstream side of the oxidizing gas supply channel 14 (FIG. 1) toward the inlet 82 of the inlet shut valve 20. Is discharged from the outlet 84 of the inlet shut valve 20 to the fuel cell stack 12 (FIG. 1) side. On the other hand, as shown in FIG. 3 due to the displacement of the drive shaft 60, when the valve body 58 is driven downward, the outlet 84 is blocked, and the air flowing from the upstream side of the oxidizing gas supply channel 14 toward the fuel cell stack 12. Is interrupted.

  In the case of the outlet shut valve 22, the inlet 82 and the outlet 84 are reversed with respect to the inlet shut valve 20, as shown in FIG. When the valve body 58 is driven upward by the displacement of the drive shaft 60 (FIGS. 2 and 3), the air off-gas flows from the upstream side of the oxidizing gas system discharge passage 16 toward the inlet 82 of the outlet shut valve 22. Is discharged from the outlet 84 of the outlet shut valve 22 to the humidifier 28 side. On the other hand, when the valve body 58 is driven downward by the displacement of the drive shaft 60, the inlet 82 is blocked, and the flow of the air off-gas from the upstream side of the oxidizing gas system discharge passage 16 toward the humidifier 28 is blocked. .

  The axial displacement of the drive shaft 60 is controlled by three PSVs. That is, in the case of the inlet shut valve 20, the pressures in the valve opening pressure chamber 52 and the valve closing pressure chamber 50 are controlled by three PSVs of ViS, ViC, and ViO. In the case of the outlet shut valve 22, the pressures in the valve opening pressure chamber 52 and the valve closing pressure chamber 50 are controlled by three PSVs of VoS, VoC, and VoO.

  ViS (or VoS) shown in FIG. 1 is 3WAY, that is, a three-way valve PSV, and selectively selects one of the valve closing pressure chamber 50 and the valve opening pressure chamber 52, The gas compressor 24 is connected to the gas upstream side of the air compressor 24, and the other pressure chamber is disconnected from the gas upstream side of the air compressor 24. ViC, ViO, VoC, and VoO are all 2-way PSVs and function as exhaust valves, that is, pressure release valves.

  ViS (or VoS) changes the connection state of the flow path depending on the energized state. ViS (or VoS) connects the gas discharge side of the air compressor 24 and the valve-opening pressure chamber 52 in a state where current is not supplied (non-energized state). In addition, ViS (or VoS) connects the gas discharge side of the air compressor and the valve closing pressure chamber 50 in an energized state (energized state). ViC, ViO, VoC, and VoO are all normally closed solenoid valves that close the valve when not energized and open the valve when energized, that is, shut off the flow path when not operating.

  In FIG. 1 to FIG. 3, among the plurality of triangles representing ViS (VoS), ViC (VoC), and ViO (VoO), the triangles filled with black indicate a state where the flow path is blocked. A white triangle represents a state in which the flow paths are connected (the same applies to FIGS. 4 and 5 described later).

  The inlet shut valve 20 and the outlet shut valve 22 are closed when power generation of the fuel cell stack 12 is stopped. Next, FIG. 4 shows that when the power generation of the fuel cell stack is stopped, the inlet shut valve 20 (or the outlet shut valve 22) is changed from the open state (the state shown in FIG. 2) to the closed state (the state shown in FIG. 3). ) Will be described as a representative of the inlet shut valve 20. As shown to Fig.4 (a), in the state which has opened the inlet shut-off valve 20, all ViS, ViC, and VoO are made into the non-energized state. In this state, air whose pressure has increased from the air compressor 24 (FIG. 1) is introduced into the valve opening pressure chamber 52 via the pressure control flow path 40. In FIG. 4, the shaded area indicates that air whose pressure has increased is introduced (the same applies to FIG. 5).

  Then, from this state, as shown in FIG. 4B, ViS is energized, and the air whose pressure has increased from the air compressor 24 (FIG. 1) flows into the valve-closing pressure chamber 50 for the pressure control flow path 40. To be introduced through. Further, the valve opening pressure chamber 52 is opened to the atmosphere with ViO in an energized state, that is, a valve open state. As a result, a first force F1 directed downward is applied to the drive shaft 60 due to a pressure difference generated between the pressure in the valve closing pressure chamber 50 and the pressure in the valve opening pressure chamber 52 (atmospheric pressure). On the other hand, since the air whose pressure has been increased by the air compressor 24 is also introduced into the flow path constituting pressure chamber 56, the pressure generated between the pressure of the flow path constituting pressure chamber 56 and the pressure of the atmospheric pressure chamber 54 communicating with the atmosphere. Due to the difference, an upward second force F2 in the opposite direction to the first force F1 acts on the drive shaft 60. However, in the case of the present embodiment, as shown in FIGS. 2 and 3, the diameter of the pressure receiving area of the upper portion of the drive shaft 60 including the main diaphragm 46 is set to the lower portion of the drive shaft 60 including the sub diaphragm 48. It is sufficiently larger than the diameter of the pressure receiving area. Therefore, as shown in FIGS. 4B and 3, the drive shaft 60 is displaced downward against the second force F <b> 2 and the elastic force of the coil spring 78 (FIG. 3), and the valve body 62. Sits on the valve seat 80.

  In this state, as shown in FIG. 4C, ViS is turned off, that is, the discharge side of the air compressor 24 communicates with the valve opening pressure chamber 52. However, since ViO is open, the pressure in the valve opening pressure chamber 52 does not increase. As a result, the pressure in the valve closing pressure chamber 50 and the pressure in the pressure control flow path 40 leading to the valve closing pressure chamber 50 are maintained at a high pressure. Thus, ViS and ViC are used to maintain the pressure in the pressure control flow path 40.

  Next, after driving of the air compressor 24 is stopped, as shown in FIG. 4D, ViO is brought into a non-energized state, that is, a valve-closed state. In this case, since the pressure in the valve-opening pressure chamber 52 decreases, the state in which the pressure in the valve-closing pressure chamber 50 is larger than the pressure in the valve-opening pressure chamber 52 remains maintained. For this reason, all the PSVs of ViS, ViC, and ViO are in a non-energized state, and the inlet shut valve 20 can be maintained in the closed state even though the inlet shut valve 20 is normally open. Thus, ViS and ViC maintain the pressure in the pressure control flow path 40 leading to the valve closing pressure chamber 52, thereby closing the normally open inlet shut valve 20. Similarly, the normally open type outlet shut valve 22 (FIG. 1) also controls the VoS, VoC, and VoO to change from the open state to the closed state when the fuel cell stack 12 stops generating power. The valve closed state is maintained with all the PSVs of VoS, VoC, and VoO being de-energized.

  On the other hand, the humidifier bypass valve 18 shown in FIG. 1 is a normally closed shut valve in which the valve body 58 is closed in a normal state in which all the pressure chambers provided therein have the same pressure. Although the detailed structure of the humidifier bypass valve 18 is not shown, the coil spring 78 (see FIGS. 2 and 3) has the same structure as the inlet shut valve 20 or the outlet shut valve 22 shown in FIGS. The cylindrical member 64 has a structure provided between the upper surface of the bottom plate portion and the lower surface of the partition portion 44. In the humidifier bypass valve 18, a coil spring is provided between the upper surface of a member fixed to the upper end of the valve body 58, such as the restraining member 74 (see FIGS. 2 and 3), and the lower surface of the housing 42. Thus, a normally closed shut valve can also be used (see the schematic diagram in FIG. 1).

  As shown in FIG. 1, the humidifier bypass valve 18 has a valve closing pressure chamber 50 in the PSV VbC side pressure control flow path 40 and a pressure control flow path 40 in the PSV VbO side. The valve pressure chambers 52 are connected to each other.

  When the valve body 58 is driven upward by the displacement of the drive shaft 60, the air flowing from the upstream side of the humidifier bypass passage 32 toward the inlet 82 of the humidifier bypass valve 18 is output from the outlet 84 of the humidifier bypass valve 18. It is discharged to the fuel cell stack 12 side. On the other hand, when the valve body 58 is driven downward by the displacement of the drive shaft 60, the outlet 84 is blocked, and the flow of air from the upstream side of the humidifier bypass path 32 toward the fuel cell stack 12 is blocked.

  The axial displacement of the drive shaft 60 is controlled by three PSVs, VbS, VbC, and VbO, as in the case of the inlet shut valve 20 and the outlet shut valve 22. In FIG. 1, among the plurality of triangles representing VbS, VbC, and VbO, a triangle filled with black indicates a state where the flow path is blocked, and a white triangle indicates a state where the flow path is connected. Represents.

  Moreover, VbS changes the connection state of a flow path with an energization state. VbS connects the gas discharge side of the air compressor 24 and the valve-closing pressure chamber 50 when not energized (non-energized state), and discharges gas from the air compressor 24 when energized (energized state). And the valve opening pressure chamber 52 are connected. VbC and VbO are both normally closed solenoid valves that close the valve in the non-energized state and open the valve in the energized state, that is, shut off the flow path when not in operation.

  Such a humidifier bypass valve 18 is closed when power generation of the fuel cell stack 12 is stopped. When the humidifier bypass valve 18 is closed as described above, as shown in FIG. 1, all of VbS, VbC, and VbO are in a state where the valve body 58 is pressed against the valve seat by the elasticity of the coil spring. Turn on the power.

  The humidifier bypass valve 18 can be closed by introducing the air whose pressure has been increased by the air compressor 24 into the valve-closing pressure chamber 50 and opening the valve-opening pressure chamber 52 to the atmosphere. At this time, the drive shaft 60 is driven downward by the force acting downward on the drive shaft 60 due to the pressure difference between the valve opening pressure chamber 52 and the valve closing pressure chamber 50 and the elasticity of the coil spring. In this case, a force acts on the drive shaft 60 due to the pressure difference between the flow path constituting pressure chamber 56 and the atmospheric pressure chamber 54, but the portion above the drive shaft 60 including the main diaphragm 46 (see FIGS. 2 and 3). The diameter of the pressure receiving area is sufficiently larger than the diameter of the pressure receiving area of the lower portion of the drive shaft 60 including the sub diaphragm 48 (see FIGS. 2 and 3) and the elasticity of the coil spring is combined. The drive shaft 60 is displaced downward. Then, the humidifier bypass valve 18 is closed.

  As described above, VbS, VbC, VbO, ViS, ViC, ViO, VoS, VoC, VoO, which are PSVs for controlling the pressure of the humidifier bypass valve 18, the inlet shut valve 20, and the outlet shut valve 22, are It is controlled by a control unit such as an ECU. That is, when the power generation of the fuel cell stack 12 is stopped, the control unit shuts off all of the inlet shut valve 20, the humidifier bypass valve 18, and the outlet shut valve 22, that is, closes the fuel cell stack 12. The gas upstream side and the gas downstream side of the flow channel on the cathode side electrode side are closely blocked.

  Next, the action when the inlet shut valve 20 and the outlet shut valve 22 are changed from the closed state to the open state at the start of the power generation operation of the fuel cell stack 12 is represented by the inlet shut valve 20 with reference to FIG. I will explain. FIG. 5A corresponds to FIG. 4D described above. When the inlet shut-off valve 20 is opened, the air compressor 24 (see FIG. 1) is started with ViS being in a non-energized state in FIG. 5 (a), and then, as shown in FIG. 5 (b), ViC is energized, that is, in a valve open state, the valve closing pressure chamber 50 is opened to the atmosphere. As a result, the air whose pressure has increased in the valve closing pressure chamber 50 is released to the atmosphere, and the pressure decreases. Further, the air whose pressure has increased from the air compressor 24 is introduced into the valve opening pressure chamber 52 through the pressure control flow path 40. As a result, a pressure difference is generated between the pressure in the valve opening pressure chamber 52 and the pressure in the valve closing pressure chamber 50 (atmospheric pressure).

  In addition, since the air whose pressure has been increased from the air compressor 24 is also introduced into the flow path constituting pressure chamber 56, the pressure is also between the pressure in the flow path constituting pressure chamber 56 and the pressure in the atmospheric pressure chamber 54 communicating with the atmosphere. There is a difference. The pressure in the flow path constituting pressure chamber 56 is applied to the lower surface of the annular deformation portion 67 of the sub diaphragm 48 shown in FIG. For this reason, the sub diaphragm 48 pushes up the cylindrical member 64, and the drive shaft 60 is displaced upward as shown in FIGS. As a result, the drive shaft 60 has the third force F3 that acts upward on the drive shaft 60 due to the pressure difference between the flow path constituting pressure chamber 56 and the atmospheric pressure chamber 54, the valve closing pressure chamber 50, and the valve opening valve. Driven upward by both forces F3 and F4 of the fourth force F4 acting upward on the drive shaft 60 due to the pressure difference between the pressure chamber 52 and the elasticity of the coil spring 78 (FIGS. 2 and 3). To do.

  Further, with the inlet shut-off valve 20 fully opened, ViC is set in a non-energized state, that is, in a closed state, and the valve-closing pressure chamber 50 and the atmosphere are shut off. And the valve-open state is maintained in the non-energized state of all PSVs of ViS, ViC, and ViO. Similarly, in the case of the outlet shut valve 22 (FIG. 1), by controlling the VoC, the fuel cell stack 12 is changed from the closed state to the open state when the power generation operation of the fuel cell stack 12 is started, and VoS, VoC, The valve-open state is maintained in a non-energized state of all the VoO PSVs.

  On the other hand, when the humidifier bypass valve 18 shown in FIG. 1 is opened, the air whose pressure has been increased by the air compressor 24 is introduced into the valve-opening pressure chamber 52 and the valve-closing pressure chamber 50 is opened to the atmosphere. As a result, the drive shaft 60 (see FIGS. 2 and 3) is caused by the pressure difference between the flow path constituting pressure chamber 56 into which the air whose pressure has been increased by the air compressor 24 is introduced and the atmospheric pressure chamber 54 (see FIGS. 2 and 3). ) And a fourth force F4 ′ acting upward on the drive shaft 60 due to a pressure difference between the valve closing pressure chamber 50 and the valve opening pressure chamber 52. The drive shaft 60 is driven upward against the elasticity of the coil spring by the forces F3 ′ and F4 ′. Then, the humidifier bypass valve 18 is opened.

  According to the fuel cell system as described above, the inlet shut valve 20 provided in the main path 30 constituting the oxidizing gas supply flow path 14, the humidifier bypass valve 18 provided in the humidifier bypass path 32, the control unit, The control unit shuts off both the inlet shut-off valve 20 and the humidifier bypass valve 18 when power generation of the fuel cell stack 12 is stopped, whereby the gas in the flow path on the cathode side electrode side of the fuel cell stack 12 is It has a configuration that blocks the upstream side. For this reason, even when the catalyst provided in the fuel cell stack 12 is held by carbon, it is difficult to introduce new air into the fuel cell stack 12 during operation stop, and the carbon is prevented from oxidizing early. Can do. For this reason, the lifetime of the fuel cell system 10 can be improved, and good power generation performance can be ensured for a long time.

  Further, by using one of the inlet shut valve 20 and the humidifier bypass valve 18 when one of the valves fails, the fuel cell system 10 can be operated. For example, even when the inlet shut-off valve 20 fails in the closed state, by opening the humidifier bypass valve 18, new air can be supplied to the fuel cell stack 12 and the fuel cell stack 12 can be generated.

  As a result, the life of the fuel cell system 10 can be improved, good power generation performance can be ensured for a long time, and operation can be performed even when the inlet shut-off valve 20 or the humidifier bypass valve 18 fails.

  In the case of the present embodiment, all three PSVs corresponding to each of the inlet shut-off valve 20, the outlet shut-off valve 22, and the humidifier bypass valve 18 are not energized while the power generation operation is stopped. Thus, all of the inlet shut valve 20, the outlet shut valve 22, and the humidifier bypass valve 18 can be maintained in the closed state. For this reason, it can prevent more effectively that new air is supplied to the flow path inside the cathode side electrode side of the fuel cell stack 12.

  Further, the humidifier bypass valve 18 is a normally closed shut-off valve that is closed in a normal state in which all the pressure chambers are at the same pressure, and the inlet shut valve 20 and the outlet shut valve 22 are in a normal state. In the configuration of the normally open type shut-off valve that is in the open state in FIG. 1, the humidifier bypass valve 18, the inlet shut valve 20 and the outlet shut valve 22 are valves that are driven by a fluid pressure difference, and are normally open type inlet valves. A pressure control flow path 40 for supplying a fluid for generating a pressure difference to the shut valve 20 and the outlet shut valve 22, and a flow path when not operating, used to maintain the pressure in the pressure control flow path 40 Normally closed solenoid valves ViS, ViC, ViO, VoS, VoC, VoO, and an inlet shut valve 20 and an outlet shut valve. The valve 22 is at the power generation stop of the fuel cell stack 12, by maintaining the pressure in the pressure control flow path 40, the inlet shutoff valve 20 and the outlet shutoff valve 22 in a closed state. This eliminates the need for electric power for continuously shutting off the normally open inlet shut valve 20 and the outlet shut valve 22 during power generation stop, thereby reducing fuel consumption.

  In addition, since the inlet shut valve 20 and the outlet shut valve 22 are normally open type, the inlet shut valve 20 or the outlet shut valve 22 is opened by operating the ViC (or VoC) even when the ViS (or VoS) fails. It can be in a valve state. Further, even when any one of ViS, ViC, and ViO, or any failure of VoS, VoC, and VoO, the pressure in the valve closing pressure chamber 50 overcomes the elasticity of the coil spring 78 (FIGS. 2 and 3). When the pressure is not so high, the inlet shut valve 20 and the outlet shut valve 22 can be opened by the elasticity of the coil spring 78. That is, the inlet shut valve 20 and the outlet shut valve 22 can be easily opened even when PSV, which is a pressure control valve for the inlet shut valve 20 and the outlet shut valve 22, fails. For this reason, it can prevent that the fuel cell system 10 exceeds a limit pressure by the abnormal rise of the pressure in a flow path, and stops operation.

  Further, since the humidifier bypass valve 18 is normally closed, the humidifier bypass valve 18 can be kept closed by the elasticity of the coil spring even when VbS, VbC, VbO fails, and the fuel cell system 10 operates. Sometimes excessively dry air is introduced into the fuel cell stack 12, and it is possible to prevent power generation performance from being deteriorated due to insufficient humidification inside the fuel cell stack 12.

  Further, in the case of the present embodiment, after receiving the power generation stop command of the fuel cell stack 12, the control unit supplies air to the fuel cell stack 12 from the air compressor 24 through the humidifier bypass path 32 to scavenge. The operation of the air compressor 24 is controlled so as to perform processing, and further, there is a scavenging process control means for controlling the pressure of the humidifier bypass valve 18 by three PSVs of VbS, VbC, and VbO. In this case, the inlet shut valve 20 provided in the main path 30 is kept closed. As a result, moisture present in the fuel cell stack 12 can be discharged to the outside by the air from the air compressor 24. For this reason, when the power in the fuel cell stack 12 is frozen while the power generation is stopped, gas is not supplied well into the fuel cell stack 12 when the power generation operation is to be resumed, and normal power generation operation can be performed. It is possible to prevent the loss more effectively.

  Further, the scavenging process control means, as shown in FIG. 5 above, shuts down the inlet when the humidifier bypass valve 18 is not opened due to a failure of the humidifier bypass valve 18 due to freezing or the like below freezing point. It also has a function of controlling the ViC so as to change the valve 20 from the closed state to the open state and supplying air to the fuel cell stack 12 through this path 30. In order to determine such a failure of the humidifier bypass valve 18, the scavenging process control means monitors the pressure detection value of the inlet pressure sensor P1 when performing the scavenging process during the power generation stop process of the fuel cell stack 12. Then, when the monitored pressure detection value rises above a predetermined pressure threshold set in advance, it is determined that the humidifier bypass valve 18 is in a closed state failure. Such failure determination is performed while monitoring the discharge flow rate of the air compressor 24 with an air flow meter (not shown). If it is determined that the humidifier bypass valve 18 is in failure, the scavenging process control means controls ViC so that the inlet shut valve 20 is opened. As a result, air from the air compressor 24 is introduced into the fuel cell stack 12 through the main path 30, and moisture in the fuel cell stack 12 is scavenged. With such a configuration, it is possible to eliminate the inconvenience that the discharge pressure of the air compressor 24 abnormally increases and the fuel cell system 10 stops abnormally.

  When air for scavenging processing is introduced into the fuel cell stack 12 through the main path 30, the humidifier 28 is provided in the middle of the main path 30, so that the scavenging processing is performed more than in the case of normal scavenging processing. It may take time. However, even in this case, an excellent effect can be obtained because the pressure in the flow path of the fuel cell system 10 can be prevented from abnormally rising and stopping.

  Further, the scavenging process control means can also control the opening and closing of the fuel cell bypass valve 38, which is an electromagnetic valve provided in the fuel cell bypass path 36, during the scavenging process. That is, the scavenging process control means supplies the air from the air compressor 24 through the humidifier bypass valve 18 through the humidifier bypass valve 18 while the fuel cell bypass valve 38 is in an open state such as half-opening during the scavenging process. It can also be set as the structure introduce | transduced into. In this case, even when the humidifier bypass valve 18 is in a closed state failure, the discharge pressure of the air compressor 24 can be prevented from rising abnormally, and the fuel cell system 10 can be prevented from stopping abnormally. Then, while monitoring the flow detection value of the air flow meter, the pressure detection value of the inlet pressure sensor P1 is monitored, and when the pressure detection value rises above a predetermined pressure threshold value set in advance, the humidifier bypass valve 18 It is determined that the failure is a closed state. If it is determined that the humidifier bypass valve 18 is in failure, the scavenging process control means controls ViC so that the inlet shut valve 20 is opened. Further, the scavenging process control means closes the fuel cell bypass valve 38 in a state where the operation of the air compressor 24 is stopped, that is, after the scavenging process ends.

[Second Embodiment]
FIG. 6 is a cross-sectional view showing the inlet shut valve 20A (outlet shut valve 22A) constituting the fuel cell system according to the second embodiment of the present invention in the open state. As shown in FIG. 6, the inlet shut valve 20A (outlet shut valve 22A) inclines the valve body 58 with respect to the vertical direction (vertical direction in FIG. 6), and inclines the drive direction of the valve body 58 with respect to the vertical direction. The direction. Accordingly, the entire upper portion of the housing 42A is inclined with respect to the vertical direction.

  In the following, the inlet shut valve 20A will be described as a representative example. In the housing 42A, on the gas upstream side (left side in FIG. 6) and the gas downstream side (right side in FIG. 6) of the flow path constituting pressure chamber 56. The inlet side connection part 86 and the outlet side connection part 88 are provided. The entrance side connection part 86 is inclined as a whole with respect to the vertical direction, and the connection surface 90 of the connection side end part is directed in the horizontal direction. In addition, the outlet side connection portion 88 is configured such that the valve body 58 side is inclined with respect to the vertical direction, and the connection side end portion thereof is directed to the horizontal direction.

  Further, the two pipes 92 connected to the inlet side connection part 86 and the outlet side connection part 88 are arranged in the horizontal direction at least around the connection part, and the lower surfaces of the two pipes 92 are arranged in the horizontal direction. It is located on a single virtual plane α. Further, the surfaces A and B of the inlet shut valve 20 that are pressed against each other between the valve body main body 62 and the valve seat 80 are inclined with respect to the vertical direction, and the pressure surfaces A and B flow through the flow path constituting pressure chamber 56. It is low on the upstream side of the gas and high on the downstream side of the gas. When the valve body 58 is driven downward, the valve body main body 62 is pressed against the valve seat 80.

  In the case of the outlet shut valve 22, the inlet 82 and the outlet 84 are reversed with respect to the inlet shut valve 20. That is, in the case of the outlet shut valve 22, the pressing surfaces A and B are higher on the upstream side of the gas flowing in the flow path constituting pressure chamber 56 and lower on the downstream side of the gas. The humidifier bypass valve 18 has the same configuration as the inlet shut valve 20, and the inlet 82 and the outlet 84 are on the same side as the inlet shut valve 20.

According to this embodiment using the inlet shut valve 20, the outlet shut valve 22, and the humidifier bypass valve 18, the pressing surfaces A and B of the valve body main body 62 and the valve seat 80 are inclined with respect to the vertical direction. Therefore, even when water liquefied from water or water vapor is attached to the pressing surfaces A and B of the valve seat 80 in the gas flowing through the flow path constituting pressure chamber 56, the water is moved along the pressing surfaces A and B. Can be dropped. Therefore, even when used or left in a low temperature environment such as below freezing point, it is difficult to cause a situation where the valve body 58 and the valve seat 80 of each of the valves 20, 22, and 18 are fixed due to freezing and stop driving.
Since other configurations and operations are the same as those in the first embodiment, the same parts are denoted by the same reference numerals, and overlapping illustrations and descriptions are omitted.

[Third Embodiment]
Next, FIG. 7 is a flowchart showing an activation control method in the fuel cell system according to the third embodiment of the present invention. In the case of the present embodiment, the configuration of the fuel cell system itself is substantially the same as that of the first embodiment shown in FIGS. 1 to 5 described above. Will be described using the same reference numerals. In the present embodiment, when power generation of the fuel cell system 10 is started, when one of the humidifier bypass valve 18 and the inlet shut valve 20 fails, the other valve is opened, and the other valve is provided. Air is supplied to the fuel cell stack 12 through the formed flow path.

  First, air is supplied to the fuel cell stack 12 only through the humidifier bypass path 32 out of the humidifier bypass path 32 and the main path 30 when power generation is started, and after a predetermined time has elapsed, the humidifier bypass path 32 and the main path 30 Of these, the case where power is generated by supplying air to the fuel cell stack 12 only through the main path 30 will be described. It should be noted that air is first supplied to the fuel cell stack 12 through the humidifier bypass path 32 at the time of power generation startup as described above when the air that has passed through the humidifier 28 at the time of startup is supplied to the fuel cell stack 12. This is because when the temperature of the water is low, water may accumulate excessively inside and power generation may be hindered. For this reason, as described above, by supplying dry air to the fuel cell stack 12 through the humidifier bypass path 32 at the start of power generation, it is more effective that water accumulates excessively in the fuel cell stack 12. Prevent power generation performance more effectively.

  With reference to FIG. 1 and FIG. 7, a start control method in the case where air is supplied to the fuel cell stack 12 at the start of power generation will be described according to the present embodiment. First, in step S1, when an activation command is sent to the fuel cell system 12 by turning on the ignition key or the like, the control unit opens the humidifier bypass valve 18 based on the valve opening command of the humidifier bypass valve 18. Thus, a command signal for controlling opening / closing of VbS, VbC, and VbO is issued. That is, a command signal for energizing VbS and VbC is issued.

  Next, in step S2, the fuel cell bypass valve 38 is opened to a certain opening such as half open (for example, 50% opening), the air compressor 24 is operated, and the air whose pressure has increased is sent out. Next, in step S3, while monitoring the pressure detection value of the inlet pressure sensor P1 located at the outlet of the air compressor 24, the air discharge flow rate (feed amount) by the air compressor 24 reaches, for example, 80% of the set value. After reaching this time, it waits for a predetermined time of t1 sec and waits for stability. The discharge flow rate of air from the air compressor 24 is monitored by an air flow meter (not shown).

  In step S4, whether the detected pressure value of the inlet pressure sensor P1 is equal to or greater than the preset pressure threshold value Ps during the stabilization wait time in step S3, and has passed a preset duration t2, for example, several hundred msec. Determine whether or not. If an affirmative (yes) determination result is obtained in step S4, it is determined that the humidifier bypass valve 18 is in a failure state that is not normally opened, and the inlet shut-off valve 20 is opened in step S6. Issue a valve command. After this valve opening command is issued, the routine proceeds to a normal startup sequence process in step S5. As a result, the air discharged from the air compressor 24 is supplied to the fuel cell stack 12 through the main path 30, and power generation is started.

  On the other hand, if a negative (no) determination result is obtained in step S4, it is determined that the humidifier bypass valve 18 is normally opened, and in step S5, a normal startup sequence is determined. The process proceeds to processing, and the air discharged from the air compressor 24 is supplied to the fuel cell stack 12 through the humidifier bypass path 32 to start power generation. Thus, in the case of the present embodiment, the failure of the humidifier bypass valve 18 is detected from the detected pressure value detected by the inlet pressure sensor P1 which is a pressure detecting means.

  In the case of this embodiment as described above, the control unit has detected that an abnormality has occurred in the humidifier bypass valve 18, which is one of the inlet shut valve 20 and the humidifier bypass valve 18, at the time of starting. When detected, the inlet shut valve 20 which is the other valve is opened and air is supplied to the fuel cell stack 12 through this path 30, so that the fuel can be supplied regardless of the failure of the humidifier bypass valve 18. The power generation operation of the battery system 10 can be performed.

In the above description, the case where power is generated by supplying air to the fuel cell stack 12 only through the humidifier bypass path 32 out of the humidifier bypass path 32 and the main path 30 at the start of power generation has been described. . However, the present embodiment is not limited to such a case, and at the time of power generation start-up, only the inlet shut valve 20 of the inlet shut valve 20 and the humidifier bypass valve 18 is opened first. This can be implemented even when air is supplied to the fuel cell stack 12 through the path 30. In this case, a valve opening command for the inlet shut valve 20 is issued in step S1, and if a positive determination result is obtained in step S4, it is determined that a failure has occurred in the inlet shut valve 20, and humidification is performed in step S6. Command to open the bypass valve 18. Then, air is supplied to the fuel cell stack 12 through the humidifier bypass path 32 to start power generation.
Other configurations and operations are the same as those in the first embodiment shown in FIGS. 1 to 5 described above, and thus redundant description and illustration are omitted.

[Fourth Embodiment]
Next, FIG. 8 is a flowchart showing an activation control method in the fuel cell system according to the fourth embodiment of the present invention. In the case of this embodiment as well, as in the case of the third embodiment shown in FIG. 7, the configuration of the fuel cell system itself is the same as that of the first embodiment shown in FIGS. It is almost the same as the case of the form. For this reason, below, the structure of a part equivalent to FIGS. 1-5 is demonstrated using the same code | symbol. Also in the case of the present embodiment, as in the case of the third embodiment, when the power generation of the fuel cell system 10 is started, one of the humidifier bypass valve 18 and the inlet shut valve 20 At the time of failure, the other valve is opened, and air is supplied to the fuel cell stack 12 through the flow path provided with the other valve.

  Also in the case of the present embodiment, air is supplied to the fuel cell stack 12 through only the humidifier bypass path 32 out of the humidifier bypass path 32 and the main path 30 when power generation is started, and after a predetermined time has elapsed, Of the humidifier bypass path 32 and the main path 30, air is supplied to the fuel cell stack 12 only through the main path 30 to generate electricity.

  In particular, in the case of the present embodiment, an electromagnetic valve provided to drive the humidifier bypass valve 18 or the inlet shut valve 20 is used to determine whether the humidifier bypass valve 18 or the inlet shut valve 20 is faulty. A failure of the humidifier bypass valve 18 or the inlet shut valve 20 is detected from the situation of a certain PSV, that is, VbS, VbC, VbO, ViS, ViC, ViO. In the case of the present embodiment, the power source of at least one of the power lines connecting the PSV for driving the humidifier bypass valve 18 or the inlet shut valve 20, that is, VbS, VbC, VbO, and the power source. There is provided a power line abnormality detecting means for detecting a short circuit or disconnection of at least one power line of the power lines connecting the power lines or ViS, ViC, and ViO.

  The power line abnormality detection means is, for example, a power line abnormality detection circuit incorporated in an ECU that is a control unit. The power supply line abnormality detection circuit detects an abnormality that is a short circuit or disconnection of the power supply line, and the control unit detects the PSV for driving the inlet shut valve 20 or the humidifier bypass valve 18 in accordance with a detection signal indicating this abnormality. Open / close control of driving PSV is performed.

  With reference to FIG. 1 and FIG. 8, a start control method in the case where air is supplied to the fuel cell stack 12 at the start of power generation will be described according to the present embodiment. First, in step S1, when an activation command is sent to the fuel cell system 10 by turning on the ignition key or the like, the control unit opens the humidifier bypass valve 18 based on the valve opening command of the humidifier bypass valve 18. Thus, a command signal for controlling opening / closing of VbS, VbC, and VbO is issued. That is, a command signal for energizing VbS and VbC is issued.

  Next, in step S2, the command signal for controlling opening / closing of VbS, VbC, VbO in step S1 cannot be normally output. That is, the power line abnormality detection means connects any one of VbS, VbC, VbO and the power source. It is determined whether an abnormality due to a short circuit, disconnection, or the like has been detected. If it is determined by this determination that an abnormality has been detected, the activation sequence is switched in step S3. That is, the control unit controls opening / closing of ViS, ViC, and ViO that are PSVs for driving the inlet shut valve 20 so as to open the inlet shut valve 20. As a result, the air discharged from the air compressor 24 is supplied to the fuel cell stack 12 through the main path 30, and power generation is started.

  On the other hand, if it is determined in step S2 that no abnormality is detected in the power supply line, it is determined that the humidifier bypass valve 18 is normally opened, and a normal startup sequence is determined in step S4. The process proceeds to processing, and the air discharged from the air compressor 24 is supplied to the fuel cell stack 12 through the humidifier bypass path 32 to start power generation.

  Also in the case of this embodiment, the control unit has detected that an abnormality has occurred in the humidifier bypass valve 18, which is one of the inlet shut valve 20 and the humidifier bypass valve 18, at the time of starting. Is detected, the inlet shut valve 20 that is the other valve is opened and air is supplied to the fuel cell stack 12 through the main path 30, regardless of the failure of the humidifier bypass valve 18. The power generation operation of the fuel cell system 10 can be performed.

In the above description, the case where power is generated by supplying air to the fuel cell stack 12 only through the humidifier bypass path 32 out of the humidifier bypass path 32 and the main path 30 at the start of power generation has been described. . However, the present embodiment is not limited to such a case, and when the power generation is started, the inlet shut-off valve 20 is opened first of the inlet shut-off valve 20 and the humidifier bypass valve 18 and the main path is opened. Even when air is supplied to the fuel cell stack 12 through 30. In this case, in step S1, a command to open the inlet shut valve 20 is issued, and if it is determined in step S4 that the PSV power line for driving the inlet shut valve 20 is short-circuited or broken, the inlet shut valve 20 has failed. In step S3, a command to open the humidifier bypass valve 18 is issued. Then, air is supplied to the fuel cell stack 12 through the humidifier bypass path 32 to start power generation.
Other configurations and operations are the same as those in the first embodiment shown in FIGS. 1 to 5 described above, and thus redundant description and illustration are omitted.

It is a figure which shows the basic composition of the fuel cell system which concerns on the 1st Embodiment of this invention. FIG. 2 is a cross-sectional view showing the structure of an inlet shut valve (or outlet shut valve) used in the fuel cell system of FIG. 1 in a valve open state. It is sectional drawing similarly shown in a valve closing state. FIG. 5 is a schematic cross-sectional view for explaining PSV switching when the inlet shut valve is shifted from the open state to the closed state. It is a schematic sectional view for explaining switching of PSV when the inlet shut valve is shifted from the closed state to the open state. It is sectional drawing which shows the structure of the inlet shut valve (or outlet shut valve) used for the fuel cell system which concerns on the 2nd Embodiment of this invention in a valve opening state. 7 is a flowchart showing a start-up control method in a fuel cell system according to a third embodiment of the present invention. 7 is a flowchart showing a start-up control method in a fuel cell system according to a fourth embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Fuel cell system, 12 Fuel cell stack, 14 Oxidizing gas supply flow path, 16 Oxidizing gas system discharge flow path, 18 Humidifier bypass valve, 20, 20A Inlet shut valve, 22, 22A Outlet shut valve, 24 Air compressor, 26 Intercooler, 28 humidifier, 30 paths, 32 humidifier bypass path, 34 pressure regulating valve, 36 fuel cell bypass path, 38 fuel cell bypass valve, 40 pressure control flow path, 42, 42A housing, 44 partition, 46 Main diaphragm, 48 Sub-diaphragm, 50 Valve closing pressure chamber, 52 Valve opening pressure chamber, 54 Atmospheric pressure chamber, 56 Channel configuration pressure chamber, 58 Valve body, 60 Drive shaft, 62 Valve body main body, 63 Drive shaft side Cylindrical surface part, 64 cylindrical member, 66 diaphragm side cylindrical part, 67 annular deformation part, 68 housing side cylindrical surface 70, second diaphragm side cylindrical portion, 72 atmospheric communication pipe, 74 restraining member, 76 supply / discharge pipe, 78 coil spring, 80 valve seat, 82 inlet, 84 outlet, 86 inlet side connection, 88 outlet side connection , 90 connection surface, 92 piping.

Claims (7)

A fuel cell that generates electricity by an electrochemical reaction between a fuel gas and an oxidizing gas;
An oxidizing gas flow path for supplying or discharging oxidizing gas to the fuel cell, and a fuel cell system comprising:
A first shut-off valve provided in the first gas flow path constituting the oxidizing gas flow path;
A second shut-off valve provided in a second gas flow path that is a detour of the first gas flow path;
A control unit,
The control unit shuts off the gas upstream side or downstream side of the flow path on the cathode side electrode side of the fuel cell by shutting off both the first shut-off valve and the second shut-off valve when the power generation of the fuel cell is stopped. A fuel cell system. The fuel cell system according to claim 1, wherein
One of the first shut-off valve and the second shut-off valve is a normally closed shut-off valve that is closed in the normal state in which all the pressure chambers are at the same pressure. The shut-off valve is a normally open shut-off valve that is open in the normal state. The fuel cell system according to claim 2, wherein
The oxidizing gas channel is an oxidizing gas supply channel for supplying oxidizing gas to the fuel cell,
The first gas flow path is the main path that passes through the humidifier,
The second gas flow path is a humidifier bypass path that bypasses the humidifier,
The first shut-off valve is a normally open type inlet shut valve that is opened in a normal state in which all the pressure chambers are at the same pressure,
The fuel cell system, wherein the second shut-off valve is a normally closed humidifier bypass valve that is closed in a normal state. The fuel cell system according to claim 2 or 3,
The first shut-off valve and the second shut-off valve are valves that are driven by a fluid pressure difference,
A pressure control flow channel for supplying a fluid for generating a pressure difference to the other normally-open type shut-off valve of the first shut-off valve and the second shut-off valve;
A normally closed solenoid valve that is used to maintain the pressure in the pressure control flow path and shuts off the flow path when not in operation;
The normally closed solenoid valve maintains the pressure in the pressure control flow path when power generation of the fuel cell is stopped, thereby closing the other normally open type shutoff valve. . The fuel cell system according to any one of claims 1 to 4, wherein:
When the control unit detects that an abnormality has occurred in one of the first shut-off valve and the second shut-off valve at the time of start-up, the control unit opens the other shut-off valve, A fuel cell system for supplying an oxidizing gas to a fuel cell through a flow path provided with a shut-off valve. The fuel cell system according to claim 5, wherein
The control unit detects an abnormality of one of the shutoff valves from a pressure value detected by the pressure detecting means or a situation of an electromagnetic valve provided to drive the shutoff valve. The fuel cell system according to any one of claims 1 to 6, wherein
The oxidizing gas channel is an oxidizing gas supply channel for supplying an oxidizing gas to the fuel cell,
The first channel is the main path through the humidifier,
The second flow path is a humidifier bypass path that bypasses the humidifier,
The control unit is provided in this path when the second shutoff valve provided in the humidifier bypass path is not opened during the scavenging process for supplying the oxidizing gas to the fuel cell after receiving the power generation stop command of the fuel cell. A scavenging process control means for supplying an oxidizing gas to the fuel cell through the first shutoff valve.

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