JP5762263B2 - Gas supply system - Google Patents

Description

  The present invention relates to a gas supply system.

  Hydrogen (fuel gas) is supplied from a hydrogen tank to a fuel cell (hydrogen consuming (processing) device) serving as a power source for a fuel cell vehicle or the like (see Patent Document 1). A hydrogen supply passage through which hydrogen flows from the hydrogen tank to the fuel cell is provided with a pressure reducing valve for reducing the hydrogen pressure to a desired pressure. In the pressure reducing valve, the valve body is repeatedly seated (closed state) / separated (opened state) with respect to the valve seat so that the secondary side pressure becomes a desired pressure. The hydrogen supply channel is provided with a relief valve in order to prevent exposure to high pressure for a long time. The relief valve opens when the hydrogen supply flow path becomes a predetermined pressure or higher, and releases hydrogen to the outside.

JP 2006-329120 A

  By the way, the above-described hydrogen supply channel is generally provided with a shut-off valve that is opened when hydrogen is supplied. However, if a pressure reducing valve and a shut-off valve are provided separately, the number of parts increases and the number of assembly steps also increases. In order to solve this problem, a configuration in which a shutoff function is added to the pressure reducing valve can be considered.

  However, the shutoff function of the pressure reducing valve changes depending on the period of use, usage status (usage environment temperature), etc., and even if the pressure reducing valve is operated so as to exert the shutoff function in accordance with the inputted shutoff command, That is, for example, even if the valve body is seated on the valve seat and operated to close the communication port, deterioration due to the use of the O-ring (seal member) provided in the close contact portion between the valve body and the valve seat, Due to curing in a low temperature environment, the communication port may not be completely closed, and hydrogen may flow out (seat leak) from the primary pressure chamber to the secondary pressure chamber. If hydrogen leaks in this way, the secondary side pressure of the pressure reducing valve rises unexpectedly, the relief valve opens, and hydrogen may be released to the outside.

  Therefore, an object of the present invention is to provide a gas supply system in which gas is not easily released to the outside even when a seat leak occurs in a pressure reducing valve having a pressure reducing function and a shutoff function.

  As means for solving the above-mentioned problems, the present invention provides a gas supply source that supplies high-pressure gas and a gas supply source that is provided downstream of the gas supply source and that opens and closes to supply / shut off the gas from the gas supply source. A first shut-off valve that is connected to a secondary side of the first shut-off valve, a high-pressure line through which a high-pressure gas flows, a pressure-reduction mechanism that is connected to a downstream side of the high-pressure line and decompresses the gas, A pressure-reducing valve having a shut-off mechanism that shuts off gas by holding the valve body in a closed position; and a medium-pressure gas that is connected to a secondary side of the pressure-reducing valve and depressurized by the pressure-reducing valve flows. An intermediate pressure line; a gas processing means provided downstream of the intermediate pressure line for processing gas from the intermediate pressure line; and provided in the intermediate pressure line, the pressure of the intermediate pressure line being a predetermined relief pressure (described later) In the embodiment to be opened if it is P12) or more A control unit that controls a leaf valve, an intermediate pressure line pressure detecting unit that detects a pressure of the intermediate pressure line, a first cutoff valve, the cutoff mechanism, and the gas processing unit; When a system stop command is detected, a shut-off step for outputting a close command to the first shut-off valve and the shut-off mechanism, and the intermediate unit per predetermined unit time (Δt0 in the embodiment described later) after the shut-off step. A gas treatment start step of starting gas treatment by the gas treatment means when the pressure rise amount of the pressure line (ΔP2 in the embodiment described later) is equal to or greater than a predetermined pressure increase amount (predetermined ΔP0 in the embodiment described later); It is a gas supply system characterized by performing.

  According to such a configuration, when the control unit detects a system stop command, the control unit outputs a close command to the first cutoff valve and the cutoff mechanism in the cutoff step. Then, the control means starts the gas processing by the gas processing means when the pressure increase amount of the intermediate pressure line per predetermined unit time is not less than the predetermined pressure increase amount after the shut-off step in the gas processing step.

  That is, when the control means outputs a close command to the shut-off mechanism, a seat leak occurs in the pressure reducing valve while the shut-off mechanism is operating to hold the valve body in the closed position and shut off the gas. The pressure in the medium pressure line gradually increases. As described above, when the pressure of the intermediate pressure line is gradually increased and the pressure increase amount of the intermediate pressure line per predetermined unit time is equal to or larger than the predetermined pressure increase amount, the control means performs the gas processing by the gas processing means. Is started, the gas in the medium pressure line is processed (consumed, discharged, etc.). Therefore, the pressure in the intermediate pressure line is difficult to reach the predetermined relief pressure, and therefore the relief valve is difficult to open and the gas is difficult to be released to the outside. Therefore, the predetermined unit time and the predetermined pressure increase amount as the determination criteria are obtained by a preliminary test or the like, and are set to values at which it is determined that the pressure of the intermediate pressure line does not reach the predetermined relief pressure.

  As means for solving the above-mentioned problems, the present invention provides a gas supply source that supplies high-pressure gas and a gas supply source that is provided downstream of the gas supply source and that opens and closes to supply / shut off the gas from the gas supply source. A first shut-off valve that is connected to a secondary side of the first shut-off valve, a high-pressure line through which a high-pressure gas flows, a pressure-reduction mechanism that is connected to a downstream side of the high-pressure line and decompresses the gas, A pressure-reducing valve having a shut-off mechanism that shuts off gas by holding the valve body in a closed position; and a medium-pressure gas that is connected to a secondary side of the pressure-reducing valve and depressurized by the pressure-reducing valve flows. An intermediate pressure line; a gas processing means provided downstream of the intermediate pressure line for processing gas from the intermediate pressure line; and provided in the intermediate pressure line, the pressure of the intermediate pressure line being a predetermined relief pressure (described later) In the embodiment to be opened if it is P12) or more A control unit that controls a leaf valve, an intermediate pressure line pressure detecting unit that detects a pressure of the intermediate pressure line, a first cutoff valve, the cutoff mechanism, and the gas processing unit; When a system stop command is detected, a shut-off step for outputting a close command to the first shut-off valve and the shut-off mechanism, and after the shut-off step, the pressure of the intermediate pressure line is increased by a predetermined pressure (see below). In the embodiment, when the elapsed time (ΔP0 in the embodiment described later) is less than or equal to the predetermined elapsed time (predetermined Δt2 in the embodiment described later), the gas that starts the gas processing by the gas processing means And a process start step.

  According to such a configuration, when the control unit detects a system stop command, the control unit outputs a close command to the first cutoff valve and the cutoff mechanism in the cutoff step. In the gas processing step, when the elapsed time until the pressure in the intermediate pressure line increases by the predetermined pressure increase amount is equal to or less than the predetermined elapsed time after the shut-off step, the control means performs the gas processing by the gas processing means. To start.

  That is, when the control means outputs a close command to the shut-off mechanism, a seat leak occurs in the pressure reducing valve while the shut-off mechanism is operating to hold the valve body in the closed position and shut off the gas. The pressure in the medium pressure line gradually increases. In this way, when the pressure of the intermediate pressure line gradually increases, when the elapsed time until the pressure of the intermediate pressure line increases by the predetermined pressure increase amount is equal to or less than the predetermined elapsed time, the control means By starting the gas processing by the gas processing means, the gas in the medium pressure line is processed (consumed, discharged, etc.). Therefore, the pressure in the intermediate pressure line is difficult to reach the predetermined relief pressure, and therefore the relief valve is difficult to open and the gas is difficult to be released to the outside. Therefore, the predetermined pressure increase amount and the predetermined elapsed time serving as the determination criteria are obtained by a preliminary test or the like, and are set to values at which it is determined that the pressure in the intermediate pressure line does not reach the predetermined relief pressure.

As means for solving the above-mentioned problems, the present invention provides a gas supply source that supplies high-pressure gas and a gas supply source that is provided downstream of the gas supply source and that opens and closes to supply / shut off the gas from the gas supply source. A first shut-off valve that is connected to a secondary side of the first shut-off valve, a high-pressure line through which a high-pressure gas flows, a pressure-reduction mechanism that is connected to a downstream side of the high-pressure line and decompresses the gas, A pressure-reducing valve having a shut-off mechanism that shuts off gas by holding the valve body in a closed position; and a medium-pressure gas that is connected to a secondary side of the pressure-reducing valve and depressurized by the pressure-reducing valve flows. An intermediate pressure line, a gas processing means provided downstream of the intermediate pressure line, for processing gas from the intermediate pressure line, and provided in the intermediate pressure line, wherein the pressure of the intermediate pressure line is equal to or higher than a predetermined relief pressure A relief valve that opens in some cases, and the intermediate pressure line A medium pressure line pressure detecting means for detecting force, and a control means for controlling the first shutoff valve, the shutoff mechanism, and the gas processing means, and the control means detects a system stop command. A shut-off step for outputting a close command to the first shut-off valve and the shut-off mechanism, and after the shut-off step, the pressure in the intermediate pressure line is determined to open the relief valve after that and the predetermined relief pressure And a gas processing start step of starting gas processing by the gas processing means when the pressure is lower than a predetermined pressure.

According to such a configuration, the control means starts the gas processing by the gas processing means when the pressure in the intermediate pressure line is equal to or higher than a predetermined pressure after which the relief valve is determined to open after the shut-off step. And a gas processing start step. As a result, the gas in the medium pressure line is processed (consumed, discharged, etc.). Therefore, the pressure in the intermediate pressure line is difficult to reach the predetermined relief pressure, and therefore the relief valve is difficult to open and the gas is difficult to be released to the outside.
Note that it is preferable to determine whether or not the pressure in the intermediate pressure line is equal to or higher than a predetermined pressure after a predetermined time has elapsed since the blocking step.

  The gas supply system further includes a high pressure line pressure detecting means for detecting a pressure of the high pressure line, and the control means is configured such that after the gas processing start step, the pressure of the high pressure line is a predetermined high pressure line pressure (described later). In the embodiment, when it is equal to or less than P3), a gas processing stop step for stopping the gas processing by the gas processing means is executed, and the predetermined high-pressure line pressure does not increase even if a seat leak occurs in the pressure reducing valve thereafter. It is preferable that the pressure in the pressure line is set to be less than the relief pressure.

  According to such a configuration, the control means stops the gas processing by the gas processing means when the pressure of the high pressure line becomes equal to or lower than the predetermined high pressure line pressure after the gas processing start step. The predetermined high-pressure line pressure is set so that the pressure in the medium-pressure line is less than the relief pressure even if the seat leaks in the pressure reducing valve thereafter. Therefore, after the gas treatment by the gas treatment means is stopped, the relief is performed. It becomes difficult to open the valve.

  The gas supply system further includes a second shutoff valve provided in the intermediate pressure line, and the control means closes the second shutoff valve when detecting the system stop command, and starts the gas processing step. It is preferable to open the second shut-off valve before starting the gas treatment.

According to such a structure, a control means closes a 2nd cutoff valve, when a system stop command is detected. Thereby, after that, the gas in the intermediate pressure line on the primary side of the second cutoff valve does not flow out to the intermediate pressure line on the secondary side.
Further, the control means opens the second cutoff valve before starting the gas processing in the gas processing start step. Thereby, gas can be satisfactorily processed thereafter by the gas processing means.

  According to these aspects of the present invention, it is possible to provide a gas supply system in which gas is hardly released to the outside even if a seat leak occurs in a pressure reducing valve having a pressure reducing function and a shutoff function.

1 is a configuration diagram of a fuel cell system according to a first embodiment. FIG. It is a sectional side view of the 1st pressure reducing valve which concerns on 1st Embodiment, and has shown at the time of OFF of a solenoid (at the time of interruption | blocking). It is a sectional side view of the 1st pressure reducing valve which concerns on 1st Embodiment, and has shown at the time of solenoid ON (at the time of pressure reduction). It is a flowchart which shows operation | movement of the fuel cell system which concerns on 1st Embodiment. It is a time chart which shows the operation example of the fuel cell system which concerns on 1st Embodiment. It is a flowchart which shows operation | movement of the fuel cell system which concerns on 2nd Embodiment. It is a flowchart which shows operation | movement of the fuel cell system which concerns on 3rd Embodiment. It is a subflowchart of failure part estimation processing S300 of FIG.

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

≪Configuration of fuel cell system≫
A fuel cell system 100 (gas supply system) shown in FIG. 1 is mounted on a fuel cell vehicle (vehicle, moving body) (not shown). The fuel cell vehicle is, for example, an automobile, a tricycle, a motorcycle, a unicycle, a train, or the like. However, the structure mounted in the other mobile body, for example, a ship, an aircraft, may be sufficient.

  The fuel cell system 100 includes a fuel cell stack 110 (gas processing means), an anode system that supplies and discharges hydrogen (fuel gas and reactive gas) to and from the anode of the fuel cell stack 110, and a cathode of the fuel cell stack 110. A cathode system that supplies and discharges oxygen-containing air (oxidant gas, reaction gas), a power control system that controls power generation of the fuel cell stack 110, and an ECU 170 (Electronic Control Unit) that electronically controls them And.

<Fuel cell stack>
The fuel cell stack 110 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 connected in series. The single cell includes an MEA (Membrane Electrode Assembly) 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 (electrode) that sandwich the membrane.

  The anode and the cathode include a porous body having conductivity such as carbon paper, and a catalyst (Pt, Ru, etc.) supported on the anode and causing an electrode reaction in the anode and the 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 111 (fuel gas channel) and a cathode channel 112 (oxidant gas channel).

  When hydrogen is supplied to each anode via the anode flow path 111, the electrode reaction of Formula (1) occurs, and when air is supplied to each cathode via the cathode flow path 112, Formula (2) Thus, a potential difference (OCV (Open Circuit Voltage), open circuit voltage) is generated in each single cell. Next, when the fuel cell stack 110 and an external circuit such as the motor 151 are electrically connected and a current is taken out, the fuel cell stack 110 generates power.

2H ₂ → 4H ⁺ + 4e ⁻ (1)
O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O (2)

<Anode system>
The anode system includes a hydrogen tank 121 (gas supply source), a normally closed first shutoff valve 122, a first pressure reducing valve 1, a normally closed second shutoff valve 123, a second pressure reducing valve 124, An ejector 125, a relief valve 126, a normally closed purge valve 127, a high pressure sensor 131 (high pressure line pressure detection means), an intermediate pressure sensor 132 (medium pressure line pressure detection means), a pipe 122a, etc. I have.

  The hydrogen tank 121 is connected to the first shutoff valve 122, the pipe 122a, the first pressure reducing valve 1, the pipe 123a, the second shutoff valve 123, the pipe 123b, the second pressure reducing valve 124, the pipe 124a, the ejector 125, and the pipe 125a. It is connected to the inlet of the anode channel 111. When the first shut-off valve 122 and the second shut-off valve 123 are opened according to an instruction from the ECU 170, the hydrogen in the hydrogen tank 121 is supplied to the anode flow path 111 through the pipe 122a and the like.

The hydrogen tank 121 is a tank in which hydrogen is sealed at a high pressure.
The first shut-off valve 122 and the second shut-off valve 123 are constituted by, for example, electromagnetic valves that open and close a gate valve with a solenoid (actuator).

<First pressure reducing valve>
As shown in FIGS. 2 and 3, the first pressure reducing valve 1 includes a pressure reducing mechanism for reducing the pressure of hydrogen and a shut-off mechanism for shutting off hydrogen by holding the valve body 20 in the closed position. .

  Specifically, the first pressure reducing valve 1 includes a housing 10, a valve body 20 that reciprocates in the housing 10 in a predetermined direction (vertical direction in FIG. 2), and a diaphragm 31. The housing 10 is partitioned into a primary pressure chamber 12 and a secondary pressure chamber 13 by a partition wall 11. Hydrogen in the pipe 122a flows into the primary pressure chamber 12, and hydrogen in the secondary pressure chamber 13 flows out into the pipe 123a.

  In the partition wall 11, a communication port 14 that communicates the primary side pressure chamber 12 and the secondary side pressure chamber 13 is formed, and a valve rod 22 that is described later of the valve body 20 is loosely inserted in the communication port 14. . An annular valve seat 15 is formed on the primary pressure chamber 12 side of the partition wall 11 surrounding the communication port 14.

  The valve body 20 includes a disc-shaped valve head 21 disposed in the primary pressure chamber 12 and a rod-shaped valve rod 22 extending from the center of the valve head 21 toward the secondary pressure chamber 13. When the valve head 21 is seated on the valve seat 15, the first pressure reducing valve 1 is closed, and when the valve head 21 is separated from the valve seat 15, the first pressure reducing valve 1 is opened.

  The diaphragm 31 is provided so that the front side faces the secondary pressure chamber 13, and an air chamber 32 communicating with the air is formed on the back side (the side opposite to the partition wall 11). The central portion of the diaphragm 31 is sandwiched between an adapter 33 and an adapter 34, and the adapter 34 is connected to the tip of the valve stem 22. Thereby, the diaphragm 31 and the valve body 20 operate | move integrally and operate | move in the up-down direction of FIG.

  Further, the first pressure reducing valve 1 includes a compression coil spring 35 interposed between the diaphragm 31 (adapter 33) and the housing 10 in the atmospheric chamber 32. The compression coil spring 35 biases the valve body 20 in the opening direction (downward direction in FIG. 2) via the adapter 33 and the adapter 34.

  The first pressure reducing valve 1 includes a plunger 41, a compression coil spring 42, and a solenoid 43. The plunger 41 is disposed on the back side of the valve head 21 (on the side opposite to the valve seat 15) so as to advance and retreat on the same axis as the valve stem 22. The compression coil spring 42 is interposed between the plunger 41 and the housing 10, and urges the plunger 41 toward the valve body 20. The solenoid 43 is controlled to be turned on (energized) / off (non-energized) by the ECU 170 to advance and retract the plunger 41.

<First pressure reducing valve-blocking mechanism>
A blocking mechanism of the first pressure reducing valve 1 will be described.
When the solenoid 43 is turned off, the plunger 41 urged by the compression coil spring 42 contacts the back surface of the valve head 21 so that the valve head 21 is seated on the valve seat 15. When the valve head 21 is seated on the valve seat 15 in this way, the valve body 20 is held in the closed position, and hydrogen is shut off.
Accordingly, the shut-off mechanism that shuts off hydrogen by holding the valve body 20 in the closed position includes the plunger 41, the compression coil spring 42, and a part of the housing 10.

<First pressure reducing valve-pressure reducing mechanism>
The pressure reducing mechanism of the first pressure reducing valve 1 will be described. The pressure reducing mechanism functions in a state in which the first shut-off valve 122 shown in FIG. 1 is open and the solenoid 43 is turned on and the plunger 41 is separated from the valve head 21 as shown in FIG.

  The pressure in the secondary pressure chamber 13 is high, the hydrogen in the secondary pressure chamber 13 biases the diaphragm 31 upward in FIG. 2, and the hydrogen in the primary pressure chamber 12 faces the valve body 20 upward in FIG. 2 is larger than the force by which the compression coil spring 35 urges the diaphragm 31 downward in FIG. 2, the valve head 21 is seated on the valve seat 15 and the first pressure reducing valve 1 is closed. It becomes the state.

  Hydrogen is consumed in the fuel cell stack 110, the pressure in the secondary pressure chamber 13 is lowered, the hydrogen in the secondary pressure chamber 13 biases the diaphragm 31 upward in FIG. 2, and the primary pressure chamber 12 2 becomes smaller than the force of the compression coil spring 35 urging the diaphragm 31 downward in FIG. 2, the valve head 21 is moved to the valve seat 15. And the first pressure reducing valve 1 is opened. Thereafter, when hydrogen flows from the primary pressure chamber 12 into the secondary pressure chamber 13 and the pressure in the secondary pressure chamber 13 increases, the first pressure reducing valve 1 is closed.

  Here, the pressure at which the valve body 20 is seated / separated, that is, the secondary pressure of the first pressure reducing valve 1 is appropriately set by changing the spring force of the compression coil spring 35. The spring force of the compression coil spring 35 can be varied by changing the thickness, material, etc. of the wire constituting the compression coil spring 35.

  Therefore, the pressure reducing mechanism of the first pressure reducing valve 1 includes the valve body 20, the diaphragm 31, and the compression coil spring 35.

Returning to FIG. 1, the description will be continued.
The second pressure reducing valve 124 is a regulator that reduces the pressure of hydrogen supplied to the primary side (upstream side) to a predetermined secondary pressure (downstream pressure), that is, a regulator that adjusts the secondary pressure. is there. Such a second pressure reducing valve 124 incorporates a valve body, a valve seat, a diaphragm (not shown), etc., as described in, for example, Japanese Patent Application Laid-Open No. 2009-277620, and a pilot pressure input from the pipe 124b. Based on the secondary side pressure, the valve body is configured to adjust the secondary side pressure by repeating the seating / separation with respect to the valve seat. The pipe 124b is connected to a pipe 141a through which air flowing toward the cathode channel 112 flows, and the pressure of the pipe 141a is input to the second pressure reducing valve 124 as a pilot pressure.

  The ejector 125 generates a negative pressure by injecting new hydrogen from the hydrogen tank 121 with a nozzle, and sucks and mixes the anode off-gas containing hydrogen in the pipe 125b with this negative pressure, toward the anode flow path 111. A vacuum pump for discharging.

  The relief valve 126 is connected to the pipe 123a via the pipe 126a, and opens when the pressure of the pipe 123a becomes equal to or higher than the predetermined relief pressure P12, and discharges hydrogen from the pipe 123a to the outside of the vehicle.

  In the first embodiment, the pipe 122a connecting the first shutoff valve 122 and the first pressure reducing valve 1 constitutes a high-pressure line through which high-pressure hydrogen from the hydrogen tank 121 flows. In addition, the pipe 123 a connecting the first pressure reducing valve 1 and the second shutoff valve 123 and the pipe 124 a connecting the second shutoff valve 123 and the second pressure reducing valve 124 have a medium pressure reduced by the first pressure reducing valve 1. It constitutes an intermediate pressure line through which hydrogen flows. Therefore, the 2nd cutoff valve 123 is provided in the intermediate pressure line.

  The outlet of the anode channel 111 is connected to the intake port of the ejector 125 via the pipe 125b. Then, the anode off-gas containing unconsumed hydrogen discharged from the anode channel 111 is returned to the ejector 125 and then re-supplied to the anode channel 111. As a result, hydrogen circulates. The pipe 125b is provided with a gas-liquid separator (not shown) that separates liquid water accompanying the anode off gas.

  The middle of the pipe 125b is connected to a diluter 142 described later via a pipe 127a, a purge valve 127, and a pipe 127b. The purge valve 127 is periodically opened by the ECU 170 when discharging (purging) impurities (water vapor, nitrogen, etc.) contained in the anode off-gas circulating through the pipe 125b during power generation of the fuel cell stack 110.

  The high pressure sensor 131 is attached to the pipe 122a, detects the pressure P1 of the pipe 122a (high pressure line), and outputs it to the ECU 170.

  The intermediate pressure sensor 132 is attached to the pipe 123a, detects the pressure P2 of the pipe 123a (intermediate pressure line), and outputs it to the ECU 170.

<Cathode system>
The cathode system includes a compressor 141 and a diluter 142 (gas processing means).
The discharge port of the compressor 141 is connected to the inlet of the cathode channel 112 through the pipe 141a. When the compressor 141 operates in accordance with a command from the ECU 170, the compressor 141 takes in oxygen-containing air and supplies the air to the cathode channel 112 via the pipe 141a. The compressor 141, the first shut-off valve 122, and the like are powered by the fuel cell stack 110 and / or a battery 153 described later.

  The outlet of the cathode channel 112 is connected to the diluter 142 via the pipe 142a, so that the cathode off-gas discharged from the cathode channel 112 is introduced into the diluter 142 through the pipe 142a. It has become.

  The diluter 142 is a container that mixes the anode off-gas and the cathode off-gas and dilutes the hydrogen in the anode off-gas with the cathode off-gas (dilution gas), and has a dilution space therein. The diluted gas is discharged out of the vehicle via the pipe 142b.

<Power control system>
The power control system includes a motor 151, a power controller 152, and a battery 153. The motor 151 is connected to an output terminal (not shown) of the fuel cell stack 110 via the power controller 152, and the battery 153 is connected to the power controller 152. That is, the motor 151 and the battery 153 are connected to the power controller 152 in parallel.

  The motor 151 is an electric motor that generates a driving force for running the fuel cell vehicle.

  The power controller 152, in accordance with an instruction from the ECU 170, (1) a function of controlling the output (generated power, current value, voltage value) of the fuel cell stack 110, and (2) a function of controlling charging / discharging of the battery 153, It has. Such a power controller 152 includes various electronic circuits such as a DC-DC chopper circuit.

  The battery 153 is a power storage device that charges / discharges electric power, and includes, for example, an assembled battery formed by combining a plurality of lithium ion type cells.

<Other equipment>
The IG 161 is a start switch of the fuel cell system 100 (fuel cell vehicle), and is provided around the driver's seat. The IG 161 is connected to the ECU 170, and the ECU 170 detects an ON signal (system start signal) and an OFF signal (system stop signal) of the IG 161.

<ECU>
The ECU 170 (control means) is a control device that electronically controls the fuel cell system 100, and includes a CPU, a ROM, a RAM, various interfaces, an electronic circuit, and the like, and according to a program stored therein, Various devices are controlled and various processes are executed.

≪Operation of fuel cell system≫
Next, operations and effects of the fuel cell system 100 will be described with reference to FIG.
When the driver turns off the IG 161 and the ECU 170 detects an OFF signal of the IG 161, the series of processes in FIG. 4 is started.

In step S101, the ECU 170 outputs a close command to the first cutoff valve 122 and the second cutoff valve 123, closes the first cutoff valve 122 and the second cutoff valve 123, and executes the cutoff step. Further, the ECU 170 outputs an OFF command (close command) to the solenoid 43 to close the first pressure reducing valve 1 (see FIG. 2).
In parallel with this, the ECU 170 stops the compressor 141 and stops the supply of air to the cathode channel 112. In addition, ECU 170 controls power controller 152 to stop power generation of fuel cell stack 110.

  In step S102, the ECU 170 determines whether or not the pressure increase amount ΔP2 of the pipe 123a (intermediate pressure line) per predetermined unit time Δt0 is equal to or greater than the predetermined pressure increase amount ΔP0. The ECU 170 calculates the pressure increase amount ΔP2 in the immediately preceding predetermined unit time Δt0 continuously or at a predetermined cycle based on the pressure P2 of the pipe 123a (intermediate pressure line) detected via the intermediate pressure sensor 132. ing.

  The predetermined unit time Δt0 is set to a time (for example, 1 minute) that enables early determination while preventing erroneous determination (easily erroneous determination is too short) based on a preliminary test or the like (see FIG. 5). 5). The predetermined pressure increase amount ΔP0 is a pressure increase amount (when the pressure increase amount ΔP2 becomes larger than this, the pressure increase amount determined that the pressure P2 of the pipe 123a (intermediate pressure line) reaches the predetermined relief pressure P12 at which the relief valve 126 opens thereafter ( For example, 100 kPa) is set (see FIG. 5). As the predetermined unit time Δt0 becomes longer, the predetermined pressure increase amount ΔP0 increases.

  When it is determined that the pressure increase amount ΔP2 is equal to or greater than the predetermined pressure increase amount ΔP0 (S102 / Yes), the processing of the ECU 170 proceeds to step S103. On the other hand, when it is determined that the pressure increase amount ΔP2 is not equal to or greater than the predetermined pressure increase amount ΔP0 (S102, No), the ECU 170 repeats the determination in step S102.

  In step S103, the ECU 170 opens the second shut-off valve 123 before starting the hydrogen treatment in step S104. If it does so, hydrogen of piping 123a will flow into piping 123b and anode channel 111, and pressure P1 of piping 122a will fall easily. Here, the purge valve 127 remains closed.

In step S104, ECU 170 starts the hydrogen treatment, that is, executes a hydrogen (gas) treatment start step.
Specifically, ECU 170 operates compressor 141 and supplies air to cathode flow path 112. Then, ECU 170 controls power controller 152 to generate power in fuel cell stack 110 and charges battery 153 with the generated power. In addition, it is good also as a structure which supplies generated electric power to resistance (not shown) and converts into heat.

  Further, an SOC sensor for detecting the SOC (State Of Charge) of the battery 153 is provided, and priority is given to charging the battery 153 until the SOC of the battery 153 reaches the upper limit SOC. It is good also as a structure converted into. The upper limit SOC is an upper limit value for preventing the battery 153 from being overcharged.

  Then, the hydrogen in the anode channel 111 and the air (oxygen) in the cathode channel 112 are consumed with this power generation. Thereby, the 2nd pressure-reduction valve 124 opens appropriately, and hydrogen of piping 123a flows into piping 124a. And hydrogen of piping 122a flows into piping 123a, and pressure P1 of piping 122a begins to fall. In this case, the solenoid 43 may be turned on so that the first pressure reducing valve 1 can be easily opened (see the broken line in FIG. 5).

In step S105, the ECU 170 determines whether or not the pressure P1 of the pipe 122a (high pressure line) detected via the high pressure sensor 131 is equal to or lower than a predetermined high pressure line pressure P3 (for example, 10 MPa) (see FIG. 5).
The predetermined high pressure line pressure P3 is the pressure of the pipe 123a (intermediate pressure line) even if the hydrogen treatment is subsequently stopped and the solenoid 43 is turned off and a seat leak occurs in the closed (shut off) first pressure reducing valve 1. P2 is set to be less than a predetermined relief pressure at which the relief valve 126 opens.

In addition, the predetermined high-pressure line pressure P3 is set as follows.
After the hydrogen treatment is stopped, the allowable hydrogen inflow amount Q11 _in allowed to flow from the pipe 122a (high pressure line) to the pipe 123a (medium pressure line) due to the seat leak of the first pressure reducing valve 1 is given by the equation (4). An allowable hydrogen outflow amount Q11 _out allowed to flow out from the pipe 122a (high pressure line) is given by the equation (4).

Q11 _in = f (P12, Vt) -f (P10, Vt) (3)
Q11 _out = f (P3, Vk) −f (P12, Vk) (4)

In the equations (3) to (4), each parameter is as follows.
P10: Pressure in the pipe 123a (intermediate pressure line) when the hydrogen treatment is stopped (at the start of soak) P12: Predetermined relief pressure of the relief valve 126 P3: Predetermined high pressure line pressure P3
Vt: Volume of the pipe 123a (medium pressure line) Vk: Volume of the pipe 122a (high pressure line) f (P, V) indicates a function of the pressure P and the volume V.

That is, the expression (3) indicates that the allowable hydrogen inflow amount Q11 _in is calculated from the amount of hydrogen (L) present in the pipe 123a when the relief valve 126 is opened, when the hydrogen treatment is stopped (when the second shutoff valve 123 is closed, soaked) It is obtained by subtracting the amount of hydrogen (L) present in the pipe 123a at the time of start).
Further, the expression (4) indicates that the allowable hydrogen outflow amount Q11 _out is obtained when the pipe 122a is at the predetermined relief pressure P12 from the hydrogen amount (L) present in the pipe 122a when the pipe 122a is at the predetermined high pressure line pressure P3. It can be obtained by subtracting the amount of hydrogen (L) present in the pipe 122a.

Then, the expression (4) is transformed into the expression (5), and furthermore, “Q11 _in = Q11 _out ”. Therefore, when the expression (3) is substituted into the expression (5), the expression (6) is obtained.

_{f (P3, Vk) = Q11} out + f (P12, Vk) ... (5)
f (P3, Vk) = f (P12, Vt) −f (P10, Vt) + f (P12, Vk) (6)

  In the equation (6), the volume Vt of the pipe 123a, the volume Vk of the pipe 122a, and the predetermined relief pressure P12 are fixed values. Therefore, the pressure P2 of the pipe 123a is detected every time the determination in step S105 is performed, The predetermined high-pressure line pressure P3 that serves as a determination criterion can also be calculated as the pressure P10 when the hydrogen treatment is stopped.

  When it is determined that the pressure P1 of the pipe 122a is equal to or lower than the predetermined high-pressure line pressure P3 (S105 / Yes), the processing of the ECU 170 proceeds to step S106. On the other hand, when it determines with the pressure P1 of the piping 122a not being below the predetermined high pressure line pressure P3 (S105 * No), ECU170 repeats determination of step S106.

In step S106, the ECU 170 stops the hydrogen treatment.
Specifically, ECU 170 stops power generation of fuel cell stack 110 and stops compressor 141.

In step S107, the ECU 170 closes the second cutoff valve 123.
Thereafter, the process of ECU 170 returns to step S102 and repeats a series of processes. In addition, when repeating a series of processes in this way, if the determination result in step S102 is “Yes” again, for example, there is a possibility of seat leak in the first shut-off valve 122. No) may be lit to notify the driver.

≪Effect of fuel cell system≫
According to such a fuel cell system, the following effects are obtained.
When the close command is output to the first shut-off valve 122, the second shut-off valve 123, and the first pressure reducing valve 1, the pressure increase amount ΔP2 is equal to or greater than the predetermined pressure increase amount ΔP0 (S102 / Yes), and the first pressure decrease Since it is determined that the relief valve 126 may be opened due to a seat leak in the valve 1, the second shutoff valve 123 is opened, and the pressure P1 of the pipe 122a (high pressure line) is lowered to a predetermined high pressure line pressure P3 or less. (S105 · Yes), the relief valve 126 is not opened thereafter, and hydrogen is not released to the outside.

<< First Embodiment-Modification >>
As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can combine with embodiment mentioned later and can be changed as follows.

  Instead of step S102 in FIG. 4, it may be determined whether or not the pressure P2 of the pipe 123a (intermediate pressure line) is equal to or higher than a predetermined pressure, and if the pressure P2 is equal to or higher than the predetermined pressure, the process may proceed to step S104. The predetermined pressure is set to a pressure that is lower than the predetermined relief pressure P12 at which the relief valve 126 opens, and is determined that the relief valve 126 may be opened thereafter. Such determination is preferably performed after a predetermined time has elapsed from step S101 (or step S107).

  In the above-described embodiment, the method of consuming hydrogen by generating electric power from the fuel cell stack 110 is exemplified as the hydrogen treatment method. However, for example, the purge valve 127 is appropriately set without generating electric power from the fuel cell stack 110. A method of opening and discharging hydrogen may be used. In the case of this method, in the diluter 142 (gas processing means), the hydrogen from the purge valve 127 is diluted with the cathode off gas and then discharged outside the vehicle.

  In the above-described embodiment, the configuration in which the gas is hydrogen is illustrated, but the type of gas is not limited to this, and may be nitrogen, argon, CNG gas, or the like.

  In the above-described embodiment, the configuration in which the gas supply system is incorporated in the fuel cell system 100 mounted on the fuel cell vehicle is exemplified, but the application location is not limited to this, and for example, the gas supply system is incorporated in a stationary fuel cell system. The configuration may be sufficient.

<< Second Embodiment >>
A second embodiment of the present invention will be described with reference to FIG. In addition, a different part from 1st Embodiment is demonstrated.

In the second embodiment, the process of the ECU 170 proceeds to step S201 after step S101.
In step S201, the ECU 170 determines whether or not the elapsed time Δt1 elapsed until the pressure P2 of the pipe 123a (intermediate pressure line) increases by the predetermined pressure increase amount ΔP0 is equal to or less than the predetermined elapsed time Δt2. The ECU 170 calculates the elapsed time Δt1 that has elapsed until the immediately preceding predetermined pressure increase amount ΔP0 increases based on the pressure P2 of the pipe 123a (intermediate pressure line) detected via the intermediate pressure sensor 132.

  The predetermined pressure increase amount ΔP0 is set to an increase amount (for example, 100 kPa) that enables early determination while preventing erroneous determination based on a preliminary test or the like. The predetermined elapsed time Δt2 is an elapsed time (for example, 1) when it is determined that the pressure P2 of the pipe 123a (intermediate pressure line) reaches a predetermined relief pressure P12 that the relief valve 126 opens after that, if the elapsed time Δt1 is less than this. Minutes) (see FIG. 5). When the predetermined pressure increase amount ΔP0 increases, the predetermined elapsed time Δt2 increases.

  When it is determined that the elapsed time Δt1 is equal to or shorter than the predetermined elapsed time Δt2 (S201 / Yes), the processing of the ECU 170 proceeds to step S103. On the other hand, when it is determined that the elapsed time Δt1 is not less than or equal to the predetermined elapsed time Δt2 (S201, No), the ECU 170 repeats the determination in step S201.

In the second embodiment, the process of the ECU 170 proceeds to step S202 after step S104.
In step S202, the ECU 170 determines whether or not the current pressure P1 of the pipe 122a (high pressure line) is equal to or less than ½ of the pressure P1 of the pipe 122a (high pressure line) at the start of hydrogen treatment in step S104. However, it is not limited to 1/2, and may be appropriately changed to 1/3, 1/4, or the like.

  When it determines with it being 1/2 or less (S202 * Yes), the process of ECU170 progresses to step S106. On the other hand, when it determines with it not being 1/2 or less (S202 * No), ECU170 repeats determination of step S202.

<< Second Embodiment-Modification >>
In the above-described embodiment, for example, when the determination result in step S201 is “Yes” twice, the process of step S105 in FIG. 4 is performed instead of step S202 after the second “S201 · Yes”. You may make it perform.

«Third embodiment»
A third embodiment of the present invention will be described with reference to FIGS. A different part from 1st Embodiment is demonstrated.

  In 3rd Embodiment, ECU170 performs the determination process (refer FIG. 6) of step S201 after step S101, and when it determines with step S201 * Yes, it performs the failure site | part estimation process of step S300. On the other hand, when it determines with step S201 * No, ECU170 repeats determination of step S201.

<Fault location estimation process>
The failure part estimation process (failure part diagnosis process) in step S300 will be described with reference to FIG.
In step S301, the ECU 170 determines that the hydrogen outflow amount Q2 (high pressure) _out becomes the hydrogen inflow amount Q3 (medium pressure) before and after the closing command is output to the first shutoff valve 122, the second shutoff valve 123, and the first pressure reducing valve 1. It is determined whether or not it is equal to _in .

Hydrogen outflow amount Q2 (high pressure) _out is the hydrogen outflow amount flowing _out from the pipe 122a (high pressure line) to the pipe 123a (medium pressure line), and is given by equation (7).
The hydrogen inflow amount Q3 (medium pressure) _in is the hydrogen inflow amount flowing into the pipe 123a (medium pressure line) from the pipe 122a (high pressure line), and is given by Expression (8).

Q2 (high pressure) _out = f (P25, Vk) −f (P24, Vk) (7)
Q3 (intermediate pressure) _in = f (P21, Vt) -f (P20, Vt) (8)

In the equations (7) to (8), each parameter is as follows.
P25: Pressure of piping 122a (high pressure line) at initial time P24: Pressure of piping 122a (high pressure line) at failure site estimation processing Vk: Volume of piping 122a (high pressure line) P21: Pipe 123a at initial time (medium pressure line) ) Pressure P20: pressure of the pipe 123a (intermediate pressure line) during failure site estimation processing Vt: volume of the pipe 123a (intermediate pressure line)

Note that the initial time is before the closing command is output to the first cutoff valve 122, the second cutoff valve 123, and the first pressure reducing valve 1. During the failure site estimation process, a closing command is being output to the first cutoff valve 122, the second cutoff valve 123, and the first pressure reducing valve 1.
Further, the pressure P25 and the pressure P24 are detected via the high pressure sensor 131, and the pressure P21 and the pressure P20 are detected via the intermediate pressure sensor 132. Volume Vk and volume Vt are fixed values.

When it is determined that the hydrogen outflow amount Q2 (high pressure) _out is equal to the hydrogen inflow amount Q3 (intermediate pressure) _in (S301, Yes), the processing of the ECU 170 proceeds to step S302. On the other hand, when it is determined that the hydrogen outflow amount Q2 (high pressure) _out is not equal to the hydrogen inflow amount Q3 (medium pressure) _in (S301, No), the processing of the ECU 170 proceeds to step S303.

In step S302, the ECU 170 estimates that the first pressure reducing valve 1 is poorly shut off, that is, a seat leak has occurred in the first pressure reducing valve 1, and temporarily stores this with a flag or the like. In addition, it is good also as a structure which memorize | stores and distinguishes from step S304 and S305 mentioned later, and alert | reports (changes the number of lighting of a warning lamp etc.) distinctively.
Thereafter, the processing of ECU 170 proceeds to step S103 in FIG. 7 through END.

In step S303, the ECU 170 determines whether or not the hydrogen outflow amount Q2 (high pressure) _out is larger than the hydrogen inflow amount Q3 (medium pressure) _in .

When it is determined that the hydrogen outflow amount Q2 (high pressure) _out is larger than the hydrogen inflow amount Q3 (intermediate pressure) _in (S303 / Yes), the processing of the ECU 170 proceeds to step S304.
On the other hand, when it is determined that the hydrogen outflow amount Q2 (high pressure) _out is not larger than the hydrogen inflow amount Q3 (intermediate pressure) _in (S303, No), the processing of the ECU 170 proceeds to step S305. When the process proceeds to step S305 in this way, ECU 170 determines that hydrogen outflow amount Q2 (high pressure) _out is smaller than hydrogen inflow amount Q3 (medium pressure) _in .

In step S304, the ECU 170 estimates that the first pressure reducing valve 1 is poorly shut off and the pipe 123a (medium pressure line or high pressure line) is poorly sealed, and temporarily stores this with a flag or the like. The pipe 123a (medium pressure line) has a poor seal, for example, the seal at the connection portion between the pipe 123a and the first pressure reducing valve 1 or the like is bad, and hydrogen leaks from this poor seal portion. Means that.
Thereafter, the processing of ECU 170 proceeds to step S103 in FIG. 7 through END.

In step 305, the ECU 170 estimates that the first pressure reducing valve 1 has a poor shut-off and the first shut-off valve 122 has a poor seal, and temporarily stores this with a flag or the like. Note that the first shut-off valve 122 has a poor seal means that, for example, the seal between the valve seat and the valve body seated on the first shut-off valve 122 is bad, and hydrogen leaks from this poor seal portion. Means that
Thereafter, the processing of ECU 170 proceeds to step S103 in FIG. 7 through END.

1 First pressure reducing valve 20 Valve body 100 Fuel cell system (gas supply system)
110 Fuel cell stack (gas treatment means)
121 Hydrogen tank (gas supply source)
122 First shut-off valve 122a Piping (high pressure line)
123 Second shut-off valve 123a, 123b Piping (medium pressure line)
126 Relief valve 131 High pressure sensor (High pressure line pressure detection means)
132 Medium pressure sensor (Medium pressure line pressure detection means)
142 Diluter (gas treatment means)
170 ECU (control means)
P1 Pressure of the piping 122a (high pressure line) P2 Pressure of the piping 123a (medium pressure line) P3 Predetermined high pressure line pressure P12 Predetermined relief pressure that opens the relief valve 126 Δt0 Predetermined unit time Δt1 Elapsed time Δt2 Predetermined time ΔP0 Predetermined pressure increase ΔP2 Pressure increase

Claims (5)

A gas supply source for supplying high-pressure gas;
A first shut-off valve provided downstream of the gas supply source and configured to supply / shut off gas from the gas supply source by opening and closing;
A high-pressure line connected to the secondary side of the first shut-off valve and through which high-pressure gas flows;
A pressure reducing valve connected to the downstream side of the high pressure line and having a pressure reducing mechanism for reducing the pressure of the gas, and a shutoff mechanism for blocking the gas by holding the valve body in a closed position;
An intermediate pressure line connected to the secondary side of the pressure reducing valve and through which an intermediate pressure gas reduced in pressure by the pressure reducing valve flows;
A gas processing means provided downstream of the intermediate pressure line for processing a gas from the intermediate pressure line;
A relief valve provided in the intermediate pressure line and opened when the pressure of the intermediate pressure line is equal to or higher than a predetermined relief pressure;
Medium pressure line pressure detecting means for detecting the pressure of the medium pressure line;
Control means for controlling the first shut-off valve, the shut-off mechanism, and the gas processing means;
With
The control means includes
A shut-off step for outputting a close command to the first shut-off valve and the shut-off mechanism when a system stop command is detected;
A gas processing start step of starting gas processing by the gas processing means when the pressure increase amount of the intermediate pressure line per predetermined unit time is not less than a predetermined pressure increase amount after the blocking step;
The gas supply system characterized by performing. A gas supply source for supplying high-pressure gas;
A first shut-off valve provided downstream of the gas supply source and configured to supply / shut off gas from the gas supply source by opening and closing;
A high-pressure line connected to the secondary side of the first shut-off valve and through which high-pressure gas flows;
A pressure reducing valve connected to the downstream side of the high pressure line and having a pressure reducing mechanism for reducing the pressure of the gas, and a shutoff mechanism for blocking the gas by holding the valve body in a closed position;
An intermediate pressure line connected to the secondary side of the pressure reducing valve and through which an intermediate pressure gas reduced in pressure by the pressure reducing valve flows;
A gas processing means provided downstream of the intermediate pressure line for processing a gas from the intermediate pressure line;
A relief valve provided in the intermediate pressure line and opened when the pressure of the intermediate pressure line is equal to or higher than a predetermined relief pressure;
Medium pressure line pressure detecting means for detecting the pressure of the medium pressure line;
Control means for controlling the first shut-off valve, the shut-off mechanism, and the gas processing means;
With
The control means includes
A shut-off step for outputting a close command to the first shut-off valve and the shut-off mechanism when a system stop command is detected;
A gas processing start step for starting gas processing by the gas processing means when the elapsed time after the blocking step until the pressure of the intermediate pressure line increases by a predetermined pressure increase amount is equal to or less than the predetermined elapsed time; ,
The gas supply system characterized by performing. A gas supply source for supplying high-pressure gas;
A first shut-off valve provided downstream of the gas supply source and configured to supply / shut off gas from the gas supply source by opening and closing;
A high-pressure line connected to the secondary side of the first shut-off valve and through which high-pressure gas flows;
A pressure reducing valve connected to the downstream side of the high pressure line and having a pressure reducing mechanism for reducing the pressure of the gas, and a shutoff mechanism for blocking the gas by holding the valve body in a closed position;
An intermediate pressure line connected to the secondary side of the pressure reducing valve and through which an intermediate pressure gas reduced in pressure by the pressure reducing valve flows;
A gas processing means provided downstream of the intermediate pressure line for processing a gas from the intermediate pressure line;
A relief valve provided in the intermediate pressure line and opened when the pressure of the intermediate pressure line is equal to or higher than a predetermined relief pressure;
Medium pressure line pressure detecting means for detecting the pressure of the medium pressure line;
Control means for controlling the first shut-off valve, the shut-off mechanism, and the gas processing means;
With
The control means includes
A shut-off step for outputting a close command to the first shut-off valve and the shut-off mechanism when a system stop command is detected;
Gas that starts gas processing by the gas processing means when the pressure of the intermediate pressure line is determined to open the relief valve after that and is equal to or higher than a predetermined pressure lower than the predetermined relief pressure. A processing start step;
The gas supply system characterized by performing. High pressure line pressure detecting means for detecting the pressure of the high pressure line;
The control means, after the gas processing start step, when the pressure of the high pressure line is equal to or lower than a predetermined high pressure line pressure, executes a gas processing stop step of stopping the gas processing by the gas processing means,
The predetermined high-pressure line pressure is set so that the pressure in the intermediate pressure line is less than the relief pressure even if a seat leak occurs in the pressure reducing valve thereafter. 4. The gas supply system according to any one of 3 above. A second shut-off valve provided in the intermediate pressure line;
The control means includes
When the system stop command is detected, the second shutoff valve is closed,
The gas supply system according to any one of claims 1 to 4, wherein the second shut-off valve is opened before the gas process is started in the gas process start step.

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