JP2009037865A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system that can appropriately eliminate freezing of a butterfly valve. <P>SOLUTION: The fuel cell system is provided with a fuel cell stack 10 which generates power by being supplied with a reaction gas, a butterfly valve 32 arranged in an exhaust gas passage in which a gas exhausted from the fuel cell stack 10 flows; a starting instruction means to instruct starting of the fuel cell stack 10, an ice determination means which determines the existence of ice in an operating range of a valve body 34 of the butterfly valve 32; and a starting reciprocating operating means which makes reciprocating operation of the valve body 34 a plurality of times in the opening and closing direction, when the starting instruction means instructs starting and the ice determination means has determined that there is ice in the operating range. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell system including a flow rate control valve such as a butterfly valve downstream of a fuel cell.

  In recent years, a polymer electrolyte fuel cell (Polymer Electrolyte Fuel Cell) that generates electricity by generating an electrochemical reaction by supplying hydrogen (fuel gas) to the anode and air containing oxygen (oxidant gas) to the cathode. Fuel cells such as PEFC) have attracted attention. In order to generate such a fuel cell satisfactorily, it is necessary to supply hydrogen and air at an appropriate flow rate and pressure. For example, a butterfly valve (air flow control means) is used as a back pressure valve for controlling the back pressure downstream of the cathode. ) Is provided.

  On the other hand, for example, when the fuel cell is mounted on a fuel cell vehicle or the like, the fuel cell system including the fuel cell may be exposed to a low temperature environment (less than 0 ° C. or the like). When the fuel cell system is stopped under such a low temperature environment, moisture generated by power generation may freeze in the butterfly valve. Then, at the next start-up, there is a possibility that the flow rate and pressure of the air supplied to the cathode cannot be properly controlled with the butterfly valve whose inside is frozen.

  Therefore, when stopping the fuel cell system, when the butterfly valve may freeze inside after stopping, the butterfly valve is controlled so that the flow velocity of the air flowing through the inside is increased. A technique has been proposed in which water droplets and the like in a butterfly valve are blown off to prevent freezing in the butterfly valve (Patent Document 1).

Japanese Patent No. 3820992

However, Patent Document 1 describes a technique for preventing the butterfly valve from freezing, but does not describe a countermeasure technique when the butterfly valve is actually frozen.
Then, this invention makes it a subject to provide the fuel cell system which can eliminate appropriately freezing of flow control valves, such as a butterfly valve.

  As means for solving the above-mentioned problems, the present invention is arranged in a fuel cell that generates electric power by supplying a reaction gas, and an exhaust gas passage through which the gas discharged from the fuel cell flows, and controls the flow rate. A flow control valve, start instruction means for instructing start of the fuel cell, ice determination means for determining whether ice is present in an operating range of the valve body of the flow control valve, and the start instruction means are started When the ice determination means determines that ice is present in the operating range, a reciprocating operation means at start-up that reciprocates the valve body a plurality of times in the opening direction and the closing direction is provided. This is a fuel cell system.

According to such a fuel cell system, when the start instructing means instructs the start of the fuel cell, when the ice determining means determines that ice is present in the operating range of the valve body of the flow control valve, the reciprocating operation at the start is performed. The means reciprocates the valve body in the opening direction and the closing direction a plurality of times.
As described above, the valve body reciprocates a plurality of times in the opening direction and the closing direction, so that ice existing in the normal operating range of the valve body is removed. As a result, freezing of the flow control valve can be eliminated.

  In addition, in the case where the stop instructing unit for instructing to stop the power generation of the fuel cell and the stop instructing unit instruct to stop, the valve determining unit determines that the ice is present in the operating range, A fuel cell system, comprising: a reciprocating means for stopping when reciprocating a plurality of times in the opening direction and the closing direction.

According to such a fuel cell system, when the stop instructing unit instructs to stop the power generation of the fuel cell, when the ice determining unit determines that ice is present in the normal operating range of the valve body, the reciprocating operation at the time of stop is performed. The means reciprocates the valve body a plurality of times in the opening direction and the closing direction.
As described above, the valve body reciprocates a plurality of times in the opening direction and the closing direction, so that ice existing in the normal operating range of the valve body is removed. As a result, freezing of the flow control valve can be eliminated. That is, after instructing the start of the fuel cell by the start instructing means, and before the freezing of the flow rate control valve is resolved, even if the stop instructing means instructed to stop, the reciprocating means at the time of stop reciprocates the valve body. Ice can be removed to prevent ice growth (expansion of freezing) after stopping.

  In addition, a fuel cell that generates electric power by being supplied with a reaction gas, a flow rate control valve that is disposed in an exhaust gas flow path through which the gas discharged from the fuel cell flows, and that instructs to stop the fuel cell A stop instruction means, an ice determination means for determining whether ice is present in the operating range of the valve body of the flow rate control valve, and when the stop instruction means instructs a stop, the ice determination means And a stop reciprocating means for reciprocating the valve element in the opening direction and the closing direction a plurality of times when it is determined that ice is present in the operating range.

  According to such a fuel cell system, when the stop instructing unit instructs to stop the power generation of the fuel cell, when the ice determining unit determines that ice is present in the normal operating range of the valve body, the reciprocating operation at the time of stop is performed. The means reciprocates the valve body a plurality of times in the opening direction and the closing direction. As described above, the valve body reciprocates a plurality of times in the opening direction and the closing direction, so that ice existing in the normal operating range of the valve body is removed. As a result, freezing of the flow control valve can be eliminated.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel cell system which can eliminate appropriately freezing of flow control valves, such as a butterfly valve, can be provided.

<< First Embodiment >>
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

≪Configuration of fuel cell system≫
A fuel cell system 1 shown in FIG. 1 is mounted on a fuel cell vehicle (mobile body) (not shown). The fuel cell system 1 includes a fuel cell stack 10, an anode system that supplies and discharges hydrogen (fuel gas and reaction gas) to and from the anode of the fuel cell stack 10, and air that contains oxygen with respect to the cathode of the fuel cell stack 10. A cathode system for supplying and discharging (oxidant gas, reaction gas), a refrigerant circulation system for circulating refrigerant (radiator liquid) so as to pass through the fuel cell stack 10 and a butterfly valve 32 (flow rate control valve) described later, and IG51 (Ignition) and an ECU 60 (Electronic Control Unit) for electronically controlling them.

<Fuel cell stack>
The fuel cell stack 10 is a stack formed by stacking a plurality of (for example, 200 to 400) solid polymer type single cells, and the plurality of single cells are electrically connected in series. The single cell includes an MEA and two conductive separators sandwiching the MEA. The MEA includes an electrolyte membrane (solid polymer membrane) made of a monovalent cation exchange membrane or the like, and an anode and a cathode sandwiching the electrolyte membrane.

  The anode and cathode are mainly composed of a conductive porous material such as carbon paper, and contain a catalyst (Pt, Ru, etc.) for causing an electrode reaction in the anode and cathode.

Each separator is formed with a groove for supplying hydrogen or air to the entire surface of each MEA, and through holes for supplying and discharging hydrogen or air to all single cells. It functions as a channel 11 (fuel gas channel) and a cathode channel 12 (oxidant gas channel). Then, when hydrogen is supplied to each anode via the anode flow path 11 and air is supplied to each cathode via the cathode flow path 12, an electrode reaction occurs, and an OCV (Open Circuit Voltage) in each single cell, Open circuit voltage).
Next, in the state where the OCV is generated in this way, the fuel cell stack 10 is connected to an external circuit (not shown) including a travel motor and the like, and when the current is taken out, the fuel cell stack 10 generates power. .

  Each separator is formed with a groove and a through-hole that constitute a refrigerant flow path 13 through which a refrigerant for cooling the fuel cell stack 10 flows.

<Anode system>
The anode system includes a hydrogen tank 21 and a shutoff valve 22.
The hydrogen tank 21 is connected to the inlet of the anode flow path 11 via a pipe 21a, a shutoff valve 22, and a pipe 22a. When the shutoff valve 22 is opened by a command from the ECU 60, hydrogen is supplied from the hydrogen tank 21 to the anode flow path 11 via the shutoff valve 22 and the like.
The outlet of the anode flow path 11 is connected to a pipe 22b, and the anode off gas discharged from the anode flow path 11 is discharged to the outside through the pipe 22b.

<Cathode system>
The cathode system includes a compressor 31 and a butterfly valve 32 (back pressure valve).
The compressor 31 is connected to the inlet of the cathode channel 12 via a pipe 31a. When the compressor 31 is operated in accordance with a command from the ECU 60, oxygen-containing air is taken in and supplied to the cathode channel 12. Further, the pipe 31a is provided with a humidifier (not shown) so that the air supplied to the cathode channel 12 is appropriately humidified.

The outlet of the cathode channel 12 is connected to a pipe 32a, a butterfly valve 32, and a pipe 32b in this order. And the cathode off gas discharged | emitted from the cathode flow path 12 is discharged | emitted outside via the piping 32a, the butterfly valve 32, and the piping 32b.
That is, the butterfly valve 32 is disposed in the exhaust gas passage through which the cathode off-gas exhausted from the fuel cell stack 10 flows.

  The butterfly valve 32 controls the flow rate and pressure (back pressure) of the air flowing through the cathode channel 12 by adjusting the opening degree. The butterfly valve 32 operates the valve body 33 (valve body), the valve body 34 disposed in the valve box 33 so as to be rotatable around a rotation shaft member 34a (see FIG. 3 and the like), and the valve body 34. A motor 35 (DC motor or the like) to be operated, and an opening sensor of the butterfly valve 32, that is, an angle sensor 36 (position detecting means) for detecting a current angle (position) of the valve body 34.

  The motor 35 is connected to a power storage device such as the fuel cell stack 10 and a battery via a control circuit (not shown), and operates with the fuel cell stack 10 and / or the power storage device as a power source. Then, for example, a PWM signal is sent from the ECU 60 to the control circuit, and the voltage applied to the motor 35 from the fuel cell stack 10 and / or the power storage device is controlled. Further, the voltage applied to the motor 35 is appropriately limited by appropriately limiting the duty ratio of the PWM signal.

  In addition, the refrigerant discharged from the refrigerant flow path 13 passes through the valve box 33. As a result, when the heat of the fuel cell stack 10 due to power generation moves to the butterfly valve 32 through the circulating refrigerant, and the butterfly valve 32 is frozen, the defrosting proceeds by the moved heat. ing.

In the present embodiment, as shown in FIGS. 4, 5, and 7, a 90 ° direction (circular cross-sectional direction of the valve box 33) with respect to the flow direction of the cathode off gas in the valve box 33 is a reference ( 0 °).
As shown in FIGS. 4 and 7, when the angle between the reference (0 °) and the valve body 34 (this is referred to as the reference full open angle θ2) is 90 °, that is, the cathode off-gas flow direction When the valve body 34 is parallel, it is assumed that the valve body 34 is disposed at the reference fully open position.
As shown in FIGS. 5 and 7, when the angle formed by the reference (0 °) and the valve body 34 is the reference fully closed angle θ1, the valve body 34 is assumed to be disposed at the reference fully closed position. The reference full-close angle θ1 is set to 0 ° or more and less than 90 ° (0 ° ≦ θ1 <90 °), for example, 10 °.

<Refrigerant circulation system>
The refrigerant circulation system is a system that circulates the refrigerant so as to pass through the refrigerant flow path 13 and the valve box 33, and includes a refrigerant pump 41, a radiator 42 (radiator), and a temperature sensor 43 (temperature detection means). I have.

  The refrigerant discharge port of the refrigerant pump 41 is connected to the inlet of the refrigerant flow path 13 via the pipe 41a. The outlet of the refrigerant flow path 13 is connected to the refrigerant suction port of the refrigerant pump 41 via the pipe 42a, the butterfly valve 32, the pipe 42b, the radiator 42, and the pipe 42c. And if the refrigerant | coolant pump 41 act | operates according to the instruction | command of ECU60, a refrigerant | coolant will circulate through the refrigerant | coolant flow path 13 and the butterfly valve 32 in order.

  The temperature sensor 43 is disposed in the pipe 42b downstream of the butterfly valve 32, and detects the temperature of the refrigerant flowing through the pipe 42b as the temperature T11 of the butterfly valve 32. The temperature sensor 43 outputs the temperature T11 to the ECU 60.

<IG>
The IG 51 is a start switch for the fuel cell vehicle and the fuel cell system 1 and is provided around the driver's seat. Further, the IG 51 is connected to the ECU 60, and the ECU 60 detects an ON / OFF signal of the IG 51.

<ECU>
The ECU 60 is a control device that electronically controls the fuel cell system 1 and includes a CPU, a ROM, a RAM, an EEPROM, various interfaces, an electronic circuit, and the like, and has various functions according to programs stored therein. To perform various processes.

<ECU-start instruction function, stop instruction function>
The ECU 60 (start-up instruction means) has a function of sending a start-up instruction to the shutoff valve 22, the compressor 31 and the refrigerant pump 41 so that the fuel cell stack 10 is started up (starts power generation) when the ON signal of the IG 51 is detected. ing.
Further, the ECU 60 (stop instruction means) has a function of sending a stop instruction to the shutoff valve 22, the compressor 31 and the refrigerant pump 41 so that the power generation of the fuel cell stack 10 is stopped when the OFF signal of the IG 51 is detected. ing.

<ECU-Butterfly valve control function>
Further, the ECU 60 (butterfly valve control means) has a function of appropriately controlling the opening degree of the butterfly valve 32 based on the depression amount of the accelerator pedal and the like, and controlling the flow rate and pressure of the air flowing through the cathode flow path 12. I have.

  Furthermore, when the ECU 60 sends an activation instruction to the shutoff valve 22 or the like so that the fuel cell stack 10 is activated, the ECU 60 determines that the butterfly valve 32 is frozen through the motor 35. It has a function of reciprocating the body 34 in the opening direction and the closing direction at a predetermined number of times (two or more times). That is, in the first embodiment, the startup reciprocating means is configured to include the motor 35 and the ECU 60.

  Further, when the ECU 60 sends a stop instruction to the shutoff valve 22 or the like so that the fuel cell stack 10 stops generating power, when it is determined that the butterfly valve 32 is frozen, the valve is It has a function of reciprocating the body 34 in the closing direction and the opening direction at a predetermined number of times (two or more times). That is, in the first embodiment, the stop reciprocating means is configured to include the motor 35 and the ECU 60.

<ECU—Start-up position detection function, determination function>
Further, when the ECU 60 (starting position detecting means) sends a starting instruction to the shutoff valve 22 and the like, the fully closed angle θ11 (fully closed position) of the butterfly valve 32 at the time of starting this time is sent via the angle sensor 36. It has a function to detect. The ECU 60 has a function of comparing the absolute value of the difference between the fully closed angle θ11 and the reference fully closed angle θ1 (reference fully closed position) with a predetermined angle difference Δθ1 (predetermined difference). The predetermined angle difference Δθ1 is related to the specifications of the butterfly valve 32, and is obtained by a preliminary test or the like and stored in the ECU 60 in advance.

<ECU-Ice determination function>
The ECU 60 determines whether or not the butterfly valve 32 is frozen based on the current temperature T11 of the butterfly valve 32 detected via the temperature sensor 43 when the IG 51 is ON (starting) and OFF (stopping). That is, it has a function of determining whether or not ice is present in the normal operating range of the valve body 34.
That is, in the first embodiment, the ice determination unit includes the temperature sensor 43 and the ECU 60.

<ECU-Freezing determination function>
Further, the ECU 60 has a function of determining whether or not the butterfly valve 32 has been frozen based on the current temperature T11 of the butterfly valve 32 and a reference temperature T1 (for example, 0 ° C.). The reference temperature T1 is a reference temperature for determining whether or not the butterfly valve 32 is frozen, is obtained by a preliminary test or the like, and is stored in the ECU 60 in advance.

<ECU-first storage function>
Further, the ECU 60 (first storage means) is configured such that, for example, the butterfly valve 32 is frozen and ice is present between the valve box 33 and the valve body 34 (see FIG. 6). When the absolute value of the difference from the reference full-closed angle θ1 is larger than a predetermined angle difference Δθ1 (predetermined difference), a first storage function for storing the full-closed angle θ11 at the time of starting this time is provided.
When the fully closed angle θ11 at the time of starting this time is stored in this way, the ECU 60 (butterfly valve control means) uses the fully closed angle θ11 as a limit value, that is, the valve body 34 is more than the fully closed angle θ11. So that the butterfly valve 32 is controlled so as not to become smaller.

<ECU-second memory function>
Furthermore, when the absolute value of the difference between the fully closed angle θ11 and the reference fully closed angle θ1 is equal to or smaller than a predetermined angle difference Δθ1 (predetermined difference), the ECU 60 (second storage means) A second storage function for updating and storing θ11 is provided.
On the other hand, when the absolute value is larger than the predetermined angle difference Δθ, the ECU 60 (butterfly valve control means) is stored in the past when the absolute value is equal to or smaller than the predetermined angle difference Δθ1 (predetermined difference). A function for controlling the butterfly valve 32 is provided based on the fully closed angle θ11 and the fully closed angle θ11 at the time of starting this time.

≪Operation of fuel cell system≫
Next, the operation at the time of starting and stopping of the fuel cell system 1 will be described together with the flow of a program (flow chart) set in the ECU 60.

<< Operation at system startup >>
The operation at the start of the fuel cell system 1 will be described with reference to FIG.
When the IG 51 is turned on, the processing shown in the flowchart of FIG. 2 starts. Specifically, the ECU 60 that has detected the ON signal of the IG 51 opens the shut-off valve 22, operates the compressor 31, supplies hydrogen and air to the fuel cell stack 10, and starts power generation of the fuel cell stack 10. Further, the ECU 60 operates the refrigerant pump 41 to circulate the refrigerant. In the initial state, the valve body 34 is disposed at the fully open position (see FIG. 4).

In step S101, the ECU 60 determines whether or not the butterfly valve 32 is frozen based on the current temperature T11 of the butterfly valve 32 detected via the temperature sensor 43 and the reference temperature T1, specifically, It is determined whether or not ice is present in the normal operating range of the valve body 34.
If the current temperature T11 is equal to or lower than the reference temperature T1, it is determined that the butterfly valve 32 is frozen (S101 / Yes), and the processing of the ECU 60 proceeds to step S102. On the other hand, if the current temperature T11 is not equal to or lower than the reference temperature T1, it is determined that the butterfly valve 32 is not frozen (S101, No), and the processing of the ECU 60 proceeds to step S103.

In step S102, the ECU 60 causes the valve element 34 to reciprocate a predetermined number of times in the opening direction and the closing direction based on the updated fully closed angle θ11. Specifically, in the closing direction, the ECU 60 controls the voltage applied to the motor 35 so that the updated full closing angle θ11 becomes a limit value. The predetermined number of times is obtained by a preliminary test or the like, and is set to about 2 to 5 times, for example, and stored in the ECU 60 in advance. The updated fully closed angle θ11 is the fully closed angle θ11 stored in step S109 at the past activation when the determination result of step S104 described later is No at the past activation.
The ice that exists in the normal operating range of the valve body 34 may be removed by the valve body 34 that reciprocates as described above.

  In step S103, the ECU 60 detects the fully closed angle θ11 of the butterfly valve 32 (this is set as the fully closed angle θ11 at the current activation). Specifically, the ECU 60 determines No in step S101 and attempts to remove ice in step S102. However, even if ice is not removed and ice remains in the normal operating range of the valve body 34, An applied voltage that does not cut the ice is applied to the motor 35, and the valve body 34 is rotated in the closing direction. Then, the maximum closing angle detected via the angle sensor 36 is set as a full closing angle θ11 at the time of starting this time.

If the temperature T11 of the butterfly valve 32 detected via the temperature sensor 43 is low (for example, less than 0 ° C.) and the butterfly valve 32 is expected to be frozen, the step of detecting the fully closed angle θ11 (S103) In order to accurately detect the fully closed angle θ11, the motor 35 may be controlled so that the rotational speed of the valve body 34 that rotates in the closing direction becomes slow.
Further, for example, when the angle θ11 of the valve body 34 detected through the angle sensor 36 does not change despite the rotation control of the valve body 34 in the closing direction, the valve body 34 bites ice. In this case, the valve body 34 is controlled to rotate in the opening direction (reverse direction), and when rotating in the opening direction, the voltage applied to the motor 35 is increased, You may make it prevent adhering to ice.

In step S104, the ECU 60 determines whether or not the absolute value of the difference between the fully closed angle θ11 at the current activation detected in step S103 and the reference fully closed angle θ1 is larger than a predetermined angle difference Δθ1.
When it is determined that the absolute value is larger than the predetermined angle difference Δθ1 (S104 / Yes), the process of the ECU 60 proceeds to step S105. In this case, foreign matter such as ice is present in the normal operating range of the valve body 34, and it is determined that the butterfly valve 32 is frozen.
On the other hand, when the absolute value is not larger than the predetermined angle difference Δθ1 (S104 · No), that is, when the absolute value is equal to or smaller than the predetermined angle difference Δθ1, the process of the ECU 60 proceeds to step S109.

  In step S105, the ECU 60 stores the fully closed angle θ11 at the time of current activation detected in step S103.

  In step S106, at the time of past activation, by passing through step S109, the updated full-close angle θ11 stored in the ECU 60 is used as a reference, and the full-close angle θ11 at the current activation detected in step S103 is limited. The butterfly valve 32 is controlled as a value (closed limit angle). This prevents the ice A from being bitten by the valve body 34.

  In step S107, the ECU 60 detects the current temperature T11 of the butterfly valve 32 via the temperature sensor 43.

In step S108, the ECU 60 determines whether or not the temperature T11 detected in step S107 is equal to or lower than the reference temperature T1.
When it is determined that the temperature T11 is equal to or lower than the reference temperature T1 (S108 / Yes), the process of the ECU 60 proceeds to step S107. In this case, the ice in the butterfly valve 32 is not defrosted and it is determined that ice is still present, and the control of the butterfly valve 32 according to step S106 is continued.
On the other hand, when it is determined that the temperature T11 is not equal to or lower than the reference temperature (S108, No), the process of the ECU 60 proceeds to step S110.

Next, when the determination result in step S104 is No, that is, when the absolute value of the difference between the fully closed angle θ11 at the time of this activation and the reference fully closed angle θ1 is not larger than the predetermined angle difference Δθ1 (predetermined Step S109 will be described which proceeds to (when the angle difference is Δθ1 or less).
In step S109, the ECU 60 updates the fully closed angle θ11, that is, stores the fully closed angle θ11 at the time of starting this time in the EEPROM or the backup RAM.

In step S110, the ECU 60 controls the butterfly valve 32 normally.
Specifically, when the process proceeds from step S109 to step S110, the ECU 60 controls the butterfly valve 32 between the fully closed angle θ11 at the time of the current activation and the reference fully opened angle θ2. On the other hand, if the determination result in step S108 is No and the process proceeds to step S110, the ECU 60 sets the fully closed angle θ11 stored in step S109 at the time of past activation as a limit value and the reference fully open angle θ2. In the meantime, the butterfly valve 32 is controlled.
Then, the processing of the ECU 60 proceeds to the end.

≪Effect at system startup≫
According to such a fuel cell system 1, when it is determined that the butterfly valve 32 is frozen when the ON signal of the IG 51 is detected and the ECU 60 instructs the start (start of power generation) of the fuel cell stack 10. Since the valve body 34 is reciprocated at a predetermined number of times (S101 / Yes), the ice in the butterfly valve 32 can be removed and the freezing can be appropriately eliminated.

  On the other hand, when such ice removal is attempted but not removed (Yes in S104), the valve element 34 is controlled with the fully closed angle θ11 at the time of starting this time as the limit value (S106). An excessive load can be prevented. In the case where the valve element 34 is controlled in this way, when the butterfly valve 32 is frozen (S108, No), the control proceeds to normal control, and the butterfly valve 32 can be appropriately controlled.

<< Operation when the system is stopped >>
Next, the operation when the fuel cell system 1 is stopped will be described with reference to FIG.
When the IG 51 is turned off, the process shown in the flowchart of FIG. 3 starts. Specifically, the ECU 60 that detects the OFF signal of the IG 51 closes the shutoff valve 22 and stops the compressor 31 to stop the power generation of the fuel cell stack 10. Further, the ECU 60 stops the refrigerant pump 41.

In step S201, the ECU 60 determines whether or not the butterfly valve 32 is frozen based on the current temperature T11 of the butterfly valve 32 and the reference temperature T1, in other words, in the same manner as in step S101. Determine whether ice is present in the operating range.
When the current temperature T11 is equal to or lower than the reference temperature T1, it is determined that the butterfly valve 32 is frozen (S201 / Yes), and the processing of the ECU 60 proceeds to step S202. On the other hand, if the current temperature T11 is not equal to or lower than the reference temperature T1, it is determined that the butterfly valve 32 is not frozen (No in S201), the process of the ECU 60 proceeds to the end, and the control at the time of stop is terminated.

In step S202, the ECU 60 causes the valve element 34 to reciprocate a predetermined number of times in the opening direction and the closing direction based on the updated fully closed angle θ11, as in step S102. Specifically, in the closing direction, the ECU 60 controls the voltage applied to the motor 35 so that the updated full closing angle θ11 becomes a limit value. The predetermined number of times is obtained by a preliminary test or the like, and is set to about 2 to 5 times, for example, and stored in the ECU 60 in advance. The ice that exists in the normal operating range of the valve body 34 may be removed by the valve body 34 that reciprocates as described above.
Thereafter, the process of the ECU 60 proceeds to the end, and the control at the time of stop is terminated.

≪Effect when system stops≫
According to such a fuel cell system 1, when it is determined that the butterfly valve 32 is frozen in the case where the ECU 60 instructs the (power generation) stop of the fuel cell stack 10 (Yes in S201), the valve body 34 Are reciprocated a predetermined number of times (S202), the ice in the butterfly valve 32 can be removed. Thereby, the growth of ice during the system stop can be suppressed.
Further, at the time of system startup, even if the IG 51 is turned off before the ice in the butterfly valve 32 is defrosted before the determination in step S108 becomes No, it is determined that the ice is frozen (Yes in S201). In step S202, the ice can be removed.

<< Second Embodiment >>
Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the control program stored in the ECU 60 is partially different, and the valve body is not determined based on the temperature T11 of the butterfly valve 32 at the start of the fuel cell system without determining whether the butterfly valve 32 is frozen. 34, the fully closed angle θ11 is detected. Then, when the ice is bitten, it is determined that the butterfly valve 32 is frozen, and then the valve body 34 is reciprocated a plurality of times in the opening direction and the closing direction to eliminate the freezing. Hereinafter, parts different from the first embodiment will be mainly described.

When the IG 51 is turned on, the processing shown in the flowchart of FIG. 8 starts. Specifically, the ECU 60 opens the shutoff valve 22, operates the compressor 31, starts power generation of the fuel cell stack 10, and operates the refrigerant pump 41.
And in 2nd Embodiment, the process of ECU60 is the freezing determination process (S101, refer FIG. 2), and the operation | movement process (S102, refer FIG. 2) of the valve body 34 of step S102 in the case of determining with being frozen. Without proceeding to step S103.
In step S103, the ECU 60 detects the fully closed angle θ11 of the butterfly valve 32.

Then, in step S104, it is determined whether or not the absolute value of the difference between the fully closed angle θ11 at the current activation detected in step S103 and the reference fully closed angle θ1 is larger than a predetermined angle difference Δθ1.
When it is determined that the absolute value is larger than the predetermined angle difference Δθ1 (S104 / Yes), the process of the ECU 60 proceeds to step S301. In this case, foreign matter such as ice is present in the normal operating range of the valve body 34, and it is determined that the butterfly valve 32 is frozen.
On the other hand, if the absolute value is not larger than the predetermined angle difference Δθ1 (S104 · No), that is, if the absolute value is equal to or smaller than the predetermined angle difference Δθ1, the process of the ECU 60 proceeds to step S109 and is the same as in the first embodiment. To control. If the determination in step 302 described later is No and the fully closed angle θ11 is detected a plurality of times in step S103, the last detected fully closed angle θ11 is stored in step S109.

  In step S301, the ECU 60 increments the counter once in order to count the number of times that the determination in step S104 is Yes.

In step S302, the ECU 60 determines whether or not the counter (the accumulated number of times that the determination in S104 is Yes) is a predetermined value (two or more times).
If the counter is equal to or greater than the predetermined value (S302 / Yes), the process of the ECU 60 proceeds to step S303.
On the other hand, when the counter is not equal to or greater than the predetermined value (S302, No), the process of the ECU 60 proceeds to step S103. Here, in step S103 which proceeds when the determination in step S302 is No, the ECU 60 again detects the fully closed angle θ11 of the valve body 34. Furthermore, when detecting the fully closed angle θ11 again in step S103, the ECU 60 reciprocates the valve element 34 in the opening direction and the closing direction a predetermined number of times (two or more times).

In step S303, the ECU 60 resets the counter.
In step S105, the ECU 60 stores the fully closed angle θ11 at the time of current activation detected in step S103. If the determination in step S302 is No and the process passes through step S103 a plurality of times, the last detected full-closed angle θ11 is stored as the full-closed angle θ11 at the time of starting this time.
Thereafter, the process of the ECU 60 proceeds to steps S106, S107, and so on, and the process proceeds in the same manner as in the first embodiment.

  In the fuel cell system according to the second embodiment, the absolute value of the difference between the fully closed angle θ11 detected in step S103 and the reference fully closed angle θ1 is larger than the predetermined angle difference Δθ1 (S104 · Yes). ), When it is determined that the butterfly valve 32 is frozen and the counter is not equal to or greater than a predetermined value (≧ 2 times) (No in S302), the process returns to Step S103, and the valve element 34 is opened and closed. And reciprocating at a predetermined number of times (two or more times). Thereby, the ice which exists in the normal operation | movement range of the valve body 34 can be removed, and the freezing can be aimed at. Moreover, the temperature sensor 43 can also be abbreviate | omitted by setting it as such a structure.

  As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to the said embodiment, For example, it can change as follows in the range which does not deviate from the meaning of this invention.

  In the second embodiment described above, ice or the like is removed while detecting the fully closed angle θ11 of the valve body 34 when the fuel cell stack 10 is started (when the IG 51 is ON). The configuration in which the valve body 34 is controlled by comparing and determining the closing angle θ1 and controlling the valve body 34 based on the determination result, with the fully closed angle θ11 at the time of activation as a limit value. May apply.

That is, at the time of start-up, ice is removed while detecting the full open angle (full open position) of the valve body 34, and whether or not the difference between the full open angle and the reference full open angle θ2 is larger than a predetermined angle difference. If it is determined and larger, the valve element 34 may be controlled using the updated full opening angle at the time of past activation as a reference and the full opening angle at the current activation as a limit value.
Further, the present invention may be applied to both the fully closed angle and the fully open angle.

  In the above-described embodiment, after the determination in step S104 becomes No, the temperature T11 of the butterfly valve 32 rises until the determination in step S108 becomes No. Although the configuration for controlling the body 34 has been exemplified (S104), for example, even if the temperature T11 of the butterfly valve 32 is equal to or lower than the reference temperature T1 (S108 / Yes), the ice melting progressed as the temperature T11 increased. It is good also as a structure which correct | amends and correct | amends the fully closed angle of the valve body 34 used as a limit value so that the operating range of the valve body 34 may spread.

  In the above-described embodiment, the configuration in which the butterfly valve 32 is disposed downstream of the cathode flow path 12 is illustrated, but the configuration in which the butterfly valve 32 is disposed downstream of the anode flow path 11 may be employed.

  In the above-described embodiment, the configuration in which the temperature T11 of the butterfly valve 32 is detected by the temperature sensor 43 that detects the temperature of the refrigerant discharged from the butterfly valve 32 through the butterfly valve 32 is exemplified. The method for detecting the temperature T11 of the valve 32 is not limited to this. For example, a configuration in which the temperature T11 is indirectly estimated based on the outside air temperature detected by the outside air temperature sensor may be used.

  In the above-described embodiment, the case where the flow control valve is the butterfly valve 32 is illustrated. However, the flow control valve is not limited thereto, and may be a needle valve, for example.

  In the above-described embodiment, the case where the fuel cell system 1 is mounted on a fuel cell vehicle is illustrated. However, for example, the fuel cell system 1 may be incorporated in a fuel cell system mounted on a motorcycle, a train, or a ship. Moreover, a stationary fuel cell system for home use or a fuel cell system incorporated in a hot water supply system may be used.

1 is a configuration diagram of a fuel cell system according to a first embodiment. FIG. It is a flowchart which shows the operation | movement at the time of starting of the fuel cell system which concerns on 1st Embodiment. It is a flowchart which shows the operation | movement at the time of the stop of the fuel cell system which concerns on 1st Embodiment. It is sectional drawing of the butterfly valve which concerns on 1st Embodiment, and shows the state by which the valve body was arrange | positioned in the reference | standard full open position. It is sectional drawing of the butterfly valve which concerns on 1st Embodiment, and shows the state by which the valve body was arrange | positioned in the reference | standard fully closed position. It is sectional drawing of the butterfly valve which concerns on 1st Embodiment, and the butterfly valve is frozen and shows the state where ice exists in the normal operation | movement range of a valve body. It is a figure which shows the relationship between the reference | standard full open position of a valve body, and a reference | standard full close position. It is a flowchart which shows the operation | movement at the time of starting of the fuel cell system which concerns on 2nd Embodiment.

Explanation of symbols

1 Fuel Cell System 10 Fuel Cell Stack 21 Hydrogen Tank 32 Butterfly Valve (Flow Control Valve)
34 Valve body 35 Motor 36 Angle sensor 43 Temperature sensor (temperature detection means)
60 ECU
T11 butterfly valve temperature

Claims (3)

A fuel cell that generates electricity by supplying reactive gas;
A flow rate control valve that is disposed in an exhaust gas passage through which the gas discharged from the fuel cell flows and controls the flow rate;
Start instruction means for instructing start of the fuel cell;
Ice determining means for determining whether ice is present in the operating range of the valve body of the flow control valve;
When the activation instruction means instructs activation, when the ice determination means determines that ice is present in the operation range, the valve element is reciprocated at a plurality of times in the opening direction and the closing direction. Means,
A fuel cell system comprising: Stop instruction means for instructing stoppage of power generation of the fuel cell;
When the stop instructing means instructs to stop, when the ice determining means determines that ice is present in the operating range, the valve body is reciprocated at a plurality of times in the opening direction and the closing direction. Means,
The fuel cell system according to claim 1, comprising: A fuel cell that generates electricity by supplying reactive gas;
A flow rate control valve that is disposed in an exhaust gas passage through which the gas discharged from the fuel cell flows and controls the flow rate;
Stop instruction means for instructing stop of the fuel cell;
Ice determining means for determining whether ice is present in the operating range of the valve body of the flow control valve;
When the stop instructing means instructs to stop, when the ice determining means determines that ice is present in the operating range, the valve body is reciprocated at a plurality of times in the opening direction and the closing direction. Means,
A fuel cell system comprising:

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