JP2007184170A - Fuel cell system and its stopping method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system stably operable even in low-temperature startup, capable of appropriately changing supply pressure of a fuel gas in response to an operating condition of a fuel cell, and high in responsiveness; and to provide its stopping method. <P>SOLUTION: This fuel cell system 1 is provided with: the fuel cell 10; a hydrogen gas piping system 3 for supplying the fuel gas to the fuel cell 10; and an injector 35 for adjusting pressure on the upstream side of the hydrogen gas piping system 3 to supply the fuel gas to the down stream side. A valve seat 61 in the injector 35 is cooled by using hydrogen gas from a hydrogen tank 30 in stopping the system. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell system in which an injector is provided in a fuel supply system of a fuel cell, and a method for stopping the fuel cell system.

  Currently, a fuel cell system including a fuel cell that receives a supply of reaction gas (fuel gas and oxidizing gas) and generates electric power has been proposed and put into practical use. Such a fuel cell system is provided with a fuel supply channel for flowing fuel gas supplied from a fuel supply source such as a hydrogen tank to the fuel cell.

By the way, when the supply pressure of the fuel gas from the fuel supply source is extremely high, a pressure regulating valve (regulator) for reducing the supply pressure to a constant value is generally provided in the fuel supply passage. In recent years, the supply pressure of the fuel gas can be changed according to the operating state of the system by providing a fuel-modulating pressure valve (variable regulator) that changes the supply pressure of the fuel gas, for example, in two stages. The technique to make is proposed (for example, refer patent document 1).
JP 2004-139984 A

  However, the conventional mechanical adjustable pressure valve as described in Patent Document 1 is difficult to change the supply pressure of the fuel gas quickly (that is, the response is low) due to its structure. In addition, it is impossible to perform high-precision pressure adjustment that changes the target pressure in multiple stages.

  In addition, since the conventional mechanically adjustable pressure valve has a relatively complicated configuration, it is large, heavy and expensive to manufacture. Furthermore, since the conventional mechanically adjustable pressure valve simply changes the supply pressure of the fuel gas, it is necessary to separately provide a cutoff valve for cutting off the supply of the fuel gas. For this reason, there exists a problem of causing the enlargement of a system (increase of installation space) and the increase in equipment cost.

  Therefore, there is a demand for a fuel cell system having a highly responsive pressure adjusting means capable of appropriately changing the supply pressure of the fuel gas in accordance with the operating state of the fuel cell. It is desired not only to have good time responsiveness but also to operate stably at the time of start-up (particularly at the time of low-temperature start-up) where the temperature environment differs from that during operation.

  The present invention has been made in view of such circumstances, and operates stably even when the system is started, and has responsiveness capable of appropriately changing the supply pressure of the fuel gas according to the operating state of the fuel cell. An object of the present invention is to provide a high fuel cell system and a method for stopping the fuel cell system.

  The fuel cell system of the present invention includes a fuel cell, a fuel supply system for supplying fuel gas to the fuel cell, an injector for adjusting a gas state on the upstream side of the fuel supply system and supplying the fuel state to the downstream side, Is provided with a cooling mechanism for cooling the valve components in the injector when the system is stopped.

  According to such a configuration, it is possible to cool the valve components in the injector in advance before closing the injector, so that the valve components are closed while being heated to a predetermined temperature or higher. Thus, sticking (sticking) of the valve components in the injector, which can occur when naturally cooled, is suppressed.

  The valve component includes at least one of a valve body, a valve seat, and a seal portion. The object to be cooled is preferably a seal portion. Further, the cooling temperature may be lower than that during system operation. The “gas state” means a gas state (flow rate, pressure, temperature, molar concentration, etc.), and particularly includes at least one of a gas flow rate and a gas pressure.

  The cooling mechanism may cool a valve component in the injector with a supply gas when the system is stopped.

  In this case, as the supply gas, it is possible to employ a fuel gas supplied from a fuel supply source connected to the fuel supply system.

  According to such a configuration, it is not necessary to add a new piping system or the like for cooling the valve components in the injector.

  The cooling mechanism closes the injector when the temperature of the fuel gas upstream of the injector when the system is stopped is equal to or higher than a predetermined temperature, and opens the injector after a predetermined stop process to open the fuel A gas may be introduced into the injector.

  According to this configuration, the fuel gas at a predetermined temperature or higher existing on the upstream side of the injector is naturally cooled while performing the predetermined stop process performed after the injector is closed. It becomes possible to cool the valve components in the injector. Examples of the predetermined stop process include a decompression process in which the fuel cell generates power for a predetermined time (for example, 8 seconds) in a state where the fuel gas supply to the fuel cell is shut off.

  In the fuel cell system of the present invention, a plurality of the fuel supply sources may be provided, and the supply gas may be a fuel gas supplied from a lower temperature fuel supply source among the plurality of fuel supply sources.

  According to such a configuration, it becomes possible to cool the valve components in the injector in a short time with a lower temperature fuel gas.

  In the fuel cell system of the present invention, the injector includes an internal channel that communicates the upstream side and the downstream side, and a valve body that is movably disposed in the internal channel and changes the open / closed state of the channel. And a valve body drive unit that drives the valve body by energization, and the cooling mechanism supplies an energization current to the valve body drive unit necessary for movement of the valve body in the opening direction upstream of the injector. It may be changed according to the side pressure.

  When the valve body drive section generates heat due to an energization current to the valve body drive section necessary for movement of the valve body in the opening direction, so-called inrush current, the fuel gas used for cooling the valve parts is heated, According to such a configuration, for example, when the upstream pressure of the injector is lower than that during operation, such as when the system is stopped, the inrush current can be lowered than during operation. By lowering, heating of the valve parts can be suppressed.

  In the fuel cell system of the present invention, the injector includes an internal channel that communicates the upstream side and the downstream side, and a valve body that is movably disposed in the internal channel and changes the open / closed state of the channel. A valve body drive unit that drives the valve body by energization, and the cooling mechanism is configured to supply an energization current to the valve body drive unit necessary for maintaining the open state of the valve body according to a system state. It may be changed.

  While the injector is open, the valve body drive unit generates heat and the fuel gas is heated by an energization current to the valve body drive unit necessary for maintaining the valve open state, so-called necessary holding current. For example, when the fuel cell system is mounted on a moving body such as a vehicle, the necessary holding current is set to be redundant in consideration of vibration G (vibration acceleration) and travel G (travel acceleration). According to such a configuration, since the moving body at the time of system stop (system state) is in the stop state, redundancy of necessary holding current can be reduced. Thereby, heating of a valve component can be suppressed.

  The cooling mechanism may open the injector after a predetermined delay time elapses after receiving a system stop command.

  Even when the fuel gas used for cooling the valve components is at a high temperature, for example, when the fuel supply source in use is after rapid filling, according to such a configuration, the predetermined delay time elapses. It becomes possible to cool the valve components using the fuel gas from the cooled fuel supply source.

  A fuel cell system stopping method according to the present invention includes a fuel cell, a fuel supply system for supplying fuel gas to the fuel cell, and adjusting the gas state on the upstream side of the fuel supply system to supply to the downstream side. A fuel cell system stopping method comprising: a step of cooling the valve components in the injector to a temperature lower than that during operation when the system is stopped.

  According to such a configuration, it is possible to cool the valve components in the injector in advance before closing the injector, so that the valve components are closed while being heated to a predetermined temperature or higher. Thus, sticking (sticking) of the valve components in the injector, which can occur when naturally cooled, is suppressed.

  According to the present invention, sticking (fixing) of the valve component in the injector, which may occur when the valve component is closed and naturally cooled while being heated to a predetermined temperature or higher, is suppressed, so It is possible to prevent the injector from falling into a state in which the valve cannot be opened when the system is started.

  Hereinafter, a fuel cell system 1 according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, an example in which the present invention is applied to an on-vehicle power generation system of a fuel cell vehicle (moving body) will be described.

  First, the configuration of the fuel cell system 1 according to the embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 1, the fuel cell system 1 according to the present embodiment includes a fuel cell 10 that generates electric power upon receiving a supply of reaction gas (oxidation gas and fuel gas), and the fuel cell 10 has an oxidant gas. An oxidizing gas piping system 2 for supplying the air, a hydrogen gas piping system 3 for supplying hydrogen gas as a fuel gas to the fuel cell 10, a control device 4 for integrated control of the entire system, and the like.

  The fuel cell 10 has a stack structure in which a required number of unit cells that generate power upon receiving a reaction gas are stacked. The electric power generated by the fuel cell 10 is supplied to a PCU (Power Control Unit) 11. The PCU 11 includes an inverter, a DC-DC converter, and the like that are disposed between the fuel cell 10 and the traction motor 12. Further, the fuel cell 10 is provided with a current sensor 13 for detecting a current during power generation.

  The oxidant gas piping system 2 includes an air supply passage 21 that supplies the oxidant gas (air) humidified by the humidifier 20 to the fuel cell 10, and an air exhaust that guides the oxidant off-gas discharged from the fuel cell 10 to the humidifier 20. A flow path 22 and an exhaust flow path 23 for guiding the oxidizing off gas from the humidifier 20 to the outside are provided. The air supply passage 21 is provided with a compressor 24 that takes in the oxidizing gas in the atmosphere and pumps it to the humidifier 20.

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

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

  The hydrogen supply flow path 31 is provided with a shutoff valve 33 that shuts off or allows the supply of hydrogen gas from the hydrogen tank 30, a regulator 34 that adjusts the pressure of the hydrogen gas, and an injector 35. A primary pressure sensor 41 and a temperature sensor 42 that detect the pressure and temperature of the hydrogen gas in the hydrogen supply flow path 31 are provided on the upstream side of the injector 35. Further, on the downstream side of the injector 35 and upstream of the junction between the hydrogen supply flow path 31 and the circulation flow path 32, a secondary side pressure sensor 43 that detects the pressure of the hydrogen gas in the hydrogen supply flow path 31. Is provided.

  The regulator 34 is a device that regulates the upstream pressure (primary pressure) to a preset secondary pressure. In the present embodiment, a mechanical pressure reducing valve that reduces the primary pressure is employed as the regulator 34. The mechanical pressure reducing valve has a structure in which a back pressure chamber and a pressure adjusting chamber are formed with a diaphragm therebetween, and the primary pressure is reduced to a predetermined pressure in the pressure adjusting chamber by the back pressure in the back pressure chamber. Thus, a publicly known configuration for the secondary pressure can be employed.

  In the present embodiment, as shown in FIG. 1, the upstream pressure of the injector 35 can be effectively reduced by arranging two regulators 34 on the upstream side of the injector 35. For this reason, the design freedom of the mechanical structure (a valve body, a housing, a flow path, a drive device, etc.) of the injector 35 can be increased.

  In addition, since the upstream pressure of the injector 35 can be reduced, it is possible to prevent the valve body 65 of the injector 35 from becoming difficult to move due to an increase in the differential pressure between the upstream pressure and the downstream pressure of the injector 35. can do. Accordingly, it is possible to widen the adjustable pressure width of the downstream pressure of the injector 35 and to suppress a decrease in responsiveness of the injector 35.

  The injector 35 is an electromagnetic drive type capable of adjusting a gas state such as a gas flow rate and a gas pressure by driving the valve body 65 directly with an electromagnetic drive force at a predetermined drive cycle and separating it from the valve seat. Open / close valve. That is, the injector 35 directly opens and closes the valves (valve body and valve seat) with an electromagnetic driving force, and has a high responsiveness because its driving cycle can be controlled to a highly responsive region.

  FIG. 3 is a cross-sectional view showing an embodiment of the injector 35. The injector 35 constitutes a part of the hydrogen supply flow path (fuel supply system) 31 and is disposed on the hydrogen tank 30 side of the hydrogen supply flow path 31 in one of the ports 51 and supplies hydrogen in the other port 52. A metal cylinder 54 having an internal flow path 53 disposed on the fuel cell 10 side of the flow path 31 is formed. The cylinder 54 includes a first passage portion 56 connected to the mouth portion 51, and A second passage portion 57 having a diameter larger than that of the first passage portion 56, which is connected to the opposite side to the mouth portion 51 of the first passage portion 56, and a side opposite to the first passage portion 56 of the second passage portion 57. From the 3rd passage part 58 larger in diameter than the 2nd passage part 57 connected, and the 2nd passage part 57 and the 3rd passage part 58 connected to the opposite side to the 2nd passage part 57 of this 3rd passage part 58 Are formed with the fourth passage portion 59 having a small diameter, and these are used as the internal flow path. 3 is configured.

  The injector 35 is movably inserted into a valve seat 61 made of a sealing member provided so as to surround the opening portion of the fourth passage portion 59 on the third passage portion 58 side, and the second passage portion 57. A metal valve body 65 having an umbrella portion 63 having a diameter larger than that of the second passage portion 57 disposed in the cylindrical portion 62 and the third passage portion 58 and having a communication hole 64 formed obliquely in the umbrella portion 63; One end side is inserted into the cylindrical portion 62 of the valve body 65 and the other end side is locked by a stopper 66 formed in the first passage portion 56 so that the valve body 65 is brought into contact with the valve seat 61 and is internally The valve body 65 is moved by moving the spring 67 that blocks the flow path 53 and the valve body 65 against the urging force of the spring 67 until it contacts the stepped portion 68 on the second passage portion 57 side of the third passage portion 58. Is connected to the internal flow path 53 through the communication hole 64 while being separated from the valve seat 61. De has a (valve body driving section) 69, a.

  In the present embodiment, the valve element 65 of the injector 35 is driven by energization control to the solenoid 69 that is an electromagnetic drive device, and the internal flow path 53 is turned on and off by turning on and off the pulsed excitation current supplied to the solenoid 69. The opening time (valve opening time) or opening area can be switched between two stages, multistage, continuous (no stage), or linear. That is, there are at least a method of changing the valve opening time and a method of changing the opening area as a method for controlling the open / close state of the injector 35.

  The flow rate and pressure of the hydrogen gas are controlled with high accuracy by controlling the gas injection time and gas injection timing of the injector 35 by the control signal output from the control device 4.

  As described above, the injector 35 supplies at least one of the opening area (opening) and the opening time of the valve body 65 provided in the internal flow path 53 of the injector 35 in order to supply a gas flow rate required downstream thereof. By changing, the gas flow rate (or hydrogen molar concentration) supplied to the downstream side (fuel cell 10 side) is adjusted.

  Since the gas flow rate is adjusted by opening and closing the valve body 65 of the injector 35 and the gas pressure supplied downstream of the injector 35 is reduced from the gas pressure upstream of the injector 35, the injector 35 is controlled by a pressure regulating valve (pressure reducing valve, Regulator). Further, in the present embodiment, a variable pressure control valve capable of changing the pressure adjustment amount (pressure reduction amount) of the upstream gas pressure of the injector 35 so as to match the required pressure within a predetermined pressure range in accordance with the gas requirement. Can also be interpreted.

  In the present embodiment, as shown in FIG. 1, the injector 35 is disposed on the upstream side of the junction A <b> 1 between the hydrogen supply flow path 31 and the circulation flow path 32. Further, as shown by a broken line in FIG. 1, when a plurality of hydrogen tanks 30 are employed as the fuel supply source, the hydrogen gas supplied from each hydrogen tank 30 joins more than the part (hydrogen gas joining part A2). The injector 35 is arranged on the downstream side.

  A discharge flow path 38 is connected to the circulation flow path 32 via a gas-liquid separator 36 and an exhaust drain valve 37. The gas-liquid separator 36 collects moisture from the hydrogen off gas. The exhaust / drain valve 37 operates according to a command from the control device 4 to discharge (purge) the moisture collected by the gas-liquid separator 36 and the hydrogen off-gas containing impurities in the circulation flow path 32 to the outside. Is.

  In addition, the circulation channel 32 is provided with a hydrogen pump 39 that pressurizes the hydrogen off gas in the circulation channel 32 and sends it to the hydrogen supply channel 31 side. The hydrogen off-gas discharged through the exhaust / drain valve 37 and the discharge passage 38 is diluted by the diluter 40 and merges with the oxidizing off-gas in the exhaust passage 23.

  The control device 4 detects an operation amount of an acceleration operation device (accelerator or the like) provided in the vehicle, receives control information such as an acceleration request value (for example, a required power generation amount from a load device such as the traction motor 12), Control the operation of various devices in the system.

  In addition to the traction motor 12, the load device is an auxiliary device (for example, a compressor 24, a hydrogen pump 39, a cooling pump motor, or the like) necessary for operating the fuel cell 10, and various types of vehicles involved in traveling of the vehicle. It is a collective term for power consumption devices including actuators used in devices (transmissions, wheel control devices, steering devices, suspension devices, etc.), occupant space air conditioners (air conditioners), lighting, audio, and the like.

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

  Specifically, as shown in FIG. 2, the control device 4 is consumed by the fuel cell 10 based on the operating state of the fuel cell 10 (current value during power generation of the fuel cell 10 detected by the current sensor 13). The amount of hydrogen gas (hereinafter referred to as “hydrogen consumption”) is calculated (fuel consumption calculation function: B1). In the present embodiment, the hydrogen consumption is calculated and updated for each calculation cycle of the control device 4 using a specific calculation formula representing the relationship between the current value of the fuel cell 10 and the hydrogen consumption.

  Further, the control device 4 determines the target pressure value of hydrogen gas (to the fuel cell 10) at the downstream position of the injector 35 based on the operating state of the fuel cell 10 (current value at the time of power generation of the fuel cell 10 detected by the current sensor 13). Target gas supply pressure) (target pressure value calculation function: B2). In the present embodiment, a position (pressure) where the secondary pressure sensor 43 is arranged for each calculation cycle of the control device 4 using a specific map representing the relationship between the current value of the fuel cell 10 and the target pressure value. The target pressure value at the pressure adjustment position where adjustment is required is calculated and updated.

  Further, the control device 4 calculates the feedback correction flow rate based on the deviation between the calculated target pressure value and the detected pressure value at the downstream position (pressure adjustment position) of the injector 35 detected by the secondary pressure sensor 43 ( Feedback correction flow rate calculation function: B3). The feedback correction flow rate is a hydrogen gas flow rate (pressure difference reduction correction flow rate) added to the hydrogen consumption in order to reduce the deviation between the target pressure value and the detected pressure value. In the present embodiment, the feedback correction flow rate is calculated and updated every calculation cycle of the control device 4 using a target tracking control law such as PI control.

  Moreover, the control apparatus 4 calculates the feedforward correction | amendment flow volume corresponding to the deviation of the target pressure value calculated last time and the target pressure value calculated this time (feedforward correction | amendment flow volume calculation function: B4). The feedforward correction flow rate is a change in the hydrogen gas flow rate due to the change in the target pressure value (correction flow corresponding to the pressure difference). In the present embodiment, the feedforward correction flow rate is calculated and updated every calculation cycle of the control device 4 using a specific calculation formula representing the relationship between the deviation of the target pressure value and the feedforward correction flow rate. .

  Further, the control device 4 determines the static flow rate upstream of the injector 35 based on the gas state upstream of the injector 35 (hydrogen gas pressure detected by the primary pressure sensor 41 and hydrogen gas temperature detected by the temperature sensor 42). (Static flow rate calculation function: B5). In the present embodiment, the static flow rate is calculated for each calculation cycle of the control device 4 using a specific calculation formula representing the relationship between the pressure and temperature of the hydrogen gas upstream of the injector 35 and the static flow rate. We are going to update.

  Further, the control device 4 calculates the invalid injection time of the injector 35 based on the gas state upstream of the injector 35 (pressure and temperature of hydrogen gas) and the applied voltage (invalid injection time calculation function: B6). Here, the invalid injection time means the time required from when the injector 35 receives a control signal from the control device 4 until the actual injection is started. In the present embodiment, the invalid injection time is calculated for each calculation cycle of the control device 4 using a specific map representing the relationship between the pressure and temperature of the hydrogen gas upstream of the injector 35, the applied voltage, and the invalid injection time. I am going to update it.

  Further, the control device 4 calculates the injection flow rate of the injector 35 by adding the hydrogen consumption amount, the feedback correction flow rate, and the feedforward correction flow rate (injection flow rate calculation function: B7). Then, the control device 4 calculates the basic injection time of the injector 35 by multiplying the value obtained by dividing the injection flow rate of the injector 35 by the static flow rate by the drive cycle of the injector 35, and the basic injection time and the invalid injection time. Are added to calculate the total injection time of the injector 35 (total injection time calculation function: B8).

  Here, the drive cycle means a stepped (on / off) waveform cycle representing the open / close state of the injection hole of the injector 35. In the present embodiment, the drive period is set to a constant value by the control device 4.

  And the control apparatus 4 controls the gas injection time and gas injection timing of the injector 35 by outputting the control signal for implement | achieving the total injection time of the injector 35 computed through the above procedure, and fuel cell The flow rate and pressure of the hydrogen gas supplied to 10 are adjusted.

  During normal operation of the fuel cell system 1, hydrogen gas is supplied from the hydrogen tank 30 to the fuel electrode of the fuel cell 10 through the hydrogen supply channel 31, and the air that has been subjected to humidification adjustment passes through the air supply channel 21. Then, power is generated by being supplied to the oxidation electrode of the fuel cell 10. At this time, the power (required power) to be drawn from the fuel cell 10 is calculated by the control device 4, and hydrogen gas and air in an amount corresponding to the amount of power generation are supplied into the fuel cell 10. In the present embodiment, the pressure of hydrogen gas supplied to the fuel cell 10 during such normal operation is controlled with high accuracy.

  By the way, during operation of the fuel cell system 1, since the injector 35 is energized and controlled according to the output request, the valve seat 61 is heated by the heat generated by the solenoid 69 due to energization. Therefore, if the valve seat 61 is heated to a predetermined temperature or higher and the system is stopped and the injector 35 is closed, the valve seat 61 in contact with the inner wall of the cylinder 54 is reduced to a subsequent natural temperature drop. It sticks together (adheres).

  In such a case, since the force required to open the injector 35 at the next system startup increases, the operation of the valve body 65 is not stable, and the valve body 65 cannot be driven (cannot be opened). Sometimes). Such a phenomenon becomes particularly prominent when the next system startup is in a low temperature environment (for example, below freezing point).

  Therefore, when the fuel cell system 1 is stopped, the control device 4 of the present embodiment cools the valve seat 61 in the injector 35 (for example, cools to a temperature lower than that during system operation), thereby sticking (adhering) ). That is, the control device 4 according to the present embodiment controls the opening / closing operation of the shutoff valve 33 and the injector 35 to cool the valve seat 61 in the injector 35 when the system is stopped. Is configured.

  Specifically, when receiving a system stop command such as ignition OFF, for example, the control device 4 closes the shut-off valve 33, stops energization of the solenoid 69, and closes the injector 35 as well. When the temperature detected by the temperature sensor 42 is equal to or higher than a predetermined temperature, the pressure is reduced while the supply of hydrogen gas to the fuel cell 10 is cut off, and the pressure reduction processing (predetermined stop processing) is performed while the fuel cell 10 generates power. Wait for the delay time. During this decompression process, the hydrogen gas staying between the shutoff valve 33 and the injector 35 is naturally cooled.

  When the decompression process is completed, energization of the solenoid 69 is started and the injector 35 is opened. Then, hydrogen gas between the shutoff valve 33 and the injector 35 flows into the injector 35, and the valve seat 61 of the injector 35 is cooled in the process in which the hydrogen gas flows through the injector 35 as shown by the arrows in FIG. The Thereafter, energization of the solenoid 69 is stopped, the injector 35 is closed, and the fuel cell system 1 is stopped.

  As described above, when the valve element 65 is closed and exposed to a low temperature environment while the valve seat 61 is heated to a predetermined temperature or higher, the valve seat 61 is attached to (adhered to) the cylinder 54. According to the present embodiment, the valve seat 61 is cooled in advance before closing the injector when the system is stopped, so that the force required for opening the valve may increase excessively. The sticking (adhesion) between the valve seat 61 and the cylinder 54 is suppressed. Therefore, it is possible to prevent the injector 35 from becoming unopenable at the next system startup.

  Further, according to the fuel cell system 1 of the present embodiment, the operating state of the fuel cell 10 (power generation amount (power, current, voltage) of the fuel cell, the temperature of the fuel cell 10, the abnormal state of the fuel cell system 1, the fuel cell) The operating state of the injector 35 (opening of the valve body 65 of the injector 35 (gas passage area), opening time of the valve body 65 of the injector 35 (gas injection time), etc.) is set according to the abnormal state of the main body) can do.

  Therefore, the supply pressure of the fuel gas can be appropriately changed according to the operating state of the fuel cell 10, and the responsiveness can be improved. Furthermore, since the injector 35 is employed as the hydrogen gas flow rate adjustment valve and the adjustable pressure control valve, highly accurate pressure adjustment (adjustment of the hydrogen gas supply pressure to the fuel cell 10) is possible.

  That is, since the injector 35 can receive the control signal from the control device 4 according to the operating state of the fuel cell 10 and adjust the injection time and injection timing of the hydrogen gas, the conventional mechanical adjustable pressure valve The pressure adjustment can be performed more quickly and accurately. In addition, the injector 35 is smaller, lighter, and less expensive than a conventional mechanically adjustable pressure valve, so that the entire system can be reduced in size and cost.

  The above-described embodiment is an example for explaining the present invention, and the present invention is not limited to this. Various components can be appropriately designed without departing from the gist of the present invention. Moreover, you may apply combining suitably other embodiment mentioned later.

  For example, the timing of starting energization of the solenoid 69 of the injector 35 may be performed after a predetermined delay time elapses after receiving a system stop command (for example, an ignition OFF command). When the hydrogen tank 30 being used is after rapid filling, etc., when the hydrogen gas introduced into the injector 35 and used for cooling the valve seat 61 is at a high temperature that is equal to or higher than a predetermined temperature, for example, as shown in FIG. In addition, when the injector 35 is opened without any delay, the temperature of the valve seat 61 is not sufficiently lowered, and the sticking (fixing) force to the cylinder 54 does not decrease.

  On the other hand, as shown in FIG. 6, the gas temperature in the hydrogen tank 30 becomes lower as the time after filling with the hydrogen gas elapses, so that the naturally cooled hydrogen gas after the predetermined delay time elapses in the valve seat 61. By using for cooling, sticking (adhesion) of the valve seat 61 can be suppressed.

  Further, the control device 4 responds to the primary pressure (upstream pressure) of the injector 35 to the inrush current necessary for opening the injector 35, that is, to the solenoid 69 necessary for moving the valve element 65 in the opening direction. The energizing current may be changed to be lower than the inrush current during operation.

  When the injector 35 is opened, the solenoid 69 generates heat due to the inrush current flowing through the solenoid 69 and the hydrogen gas is heated, so that a necessary cooling temperature may not be obtained. For this reason, the degree by which hydrogen gas is warmed can be suppressed by making the inrush current as small as possible.

  Further, as shown in FIG. 7, the smaller the primary pressure (upstream pressure) of the injector 35, the smaller the current value necessary for opening the valve, so the minimum current value necessary for opening the valve is given to the solenoid 69. The injector 35 may be opened by giving it. In particular, when the system is stopped, since the pressure of the hydrogen supply flow path 31 is low, the primary pressure of the injector 35 is small, and the current value required for opening the valve may be small.

  Therefore, excessively heating the hydrogen gas used for cooling the valve seat 61 by lowering the inrush current when opening the injector 35 once closed when the system is stopped to be lower than the inrush current during operation. As a result, the valve seat 61 can be effectively cooled by the hydrogen gas.

  Further, the control device 4 is required to hold the holding current necessary for holding the injector 35 in the valve open state (hereinafter referred to as “necessary holding current”), that is, the valve element 65 that has once moved to the end in the opening direction. The energization current to the solenoid 69 may be changed to be lower than the necessary holding current during operation.

  In the vehicular fuel cell system, the required holding current of the injector 35 is set redundantly in consideration of acceleration / deceleration and vibration associated with traveling of the vehicle (moving body). For example, as shown in FIG. 8, since vibration G (vibration acceleration) is large during traveling, the necessary holding current for opening the injector 35 needs to have redundancy corresponding thereto. (Design point in the figure) Since the vehicle is stopped when the system is stopped, it is not necessary to consider the vibration G as when traveling.

  Therefore, the control device 4 reduces the redundancy of the required holding current by setting the required holding current when the system is stopped to be lower than the required holding current when traveling, assuming that there is no vibration. Thereby, the heat generation of the solenoid 69 can be suppressed and the degree to which the hydrogen gas used for cooling the valve seat 61 is warmed can be suppressed, so that the valve seat 61 can be effectively cooled by the hydrogen gas. .

  Further, as shown by a broken line in FIG. 1, in the fuel cell system 1 provided with a plurality of hydrogen tanks 30 as a fuel supply source, the valve seat 61 in the injector 35 can be cooled as follows when the system is stopped. it can.

  That is, the control device 4 detects the temperature of each hydrogen tank 30 when the injector 35 in the closed state is opened to cool the valve seat 61, and shuts off the hydrogen tank 30 with the lowest detected temperature. The valve 33 is selectively opened. As a result, the injector 35 can be cooled using hydrogen gas having a lower temperature. The temperature of the hydrogen tank 30 may be detected using a temperature sensor in the tank, or may be estimated from the usage history of each hydrogen tank 30.

  Further, in each of the above embodiments, the example in which the fuel cell system according to the present invention is mounted on the fuel cell vehicle has been shown. However, the present invention is applied to various moving bodies (robots, ships, aircrafts, etc.) other than the fuel cell vehicle. Such a fuel cell system can also be mounted. Further, the fuel cell system according to the present invention may be applied to a stationary power generation system used as a power generation facility for a building (house, building, etc.).

1 is a configuration diagram of a fuel cell system according to an embodiment of the present invention. It is a control block diagram for demonstrating the control aspect of the control apparatus of the fuel cell system shown in FIG. It is a longitudinal cross-sectional view of the injector used for the fuel cell system shown in FIG. It is explanatory drawing shown about the process in which the valve seat in an injector is cooled by hydrogen gas. It is the figure shown about the relationship between the valve-seat temperature in an injector, and the sticking (adhesion) force to a cylinder. It is the figure shown about the time-dependent change of hydrogen gas temperature. It is the figure which showed the relationship between the primary pressure of an injector, and the electric current value which can be opened. It is the figure which showed the relationship between the required holding current required for valve opening holding | maintenance of an injector, and the vibration of a vehicle.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 3 ... Hydrogen gas piping system (fuel supply system), 4 ... Control apparatus (cooling mechanism), 10 ... Fuel cell, 31 ... Hydrogen supply flow path, 35 ... Injector, 41 ... Primary pressure sensor, 53 ... Internal flow path, 61 ... Valve seat (valve part), 65 ... Valve body, 69 ... Solenoid (valve body drive part)

Claims (9)

In a fuel cell system comprising a fuel cell, a fuel supply system for supplying fuel gas to the fuel cell, and an injector for adjusting the gas state on the upstream side of the fuel supply system and supplying the fuel state to the downstream side,
A fuel cell system comprising a cooling mechanism for cooling valve components in the injector when the system is stopped. The fuel cell system according to claim 1, wherein
The cooling mechanism is a fuel cell system that cools valve components in the injector with a supply gas when the system is stopped. The fuel cell system according to claim 2, wherein
The fuel cell system, wherein the supply gas is a fuel gas supplied from a fuel supply source connected to the fuel supply system. The fuel cell system according to claim 3, wherein
The cooling mechanism closes the injector when the temperature of the fuel gas upstream of the injector when the system is stopped is equal to or higher than a predetermined temperature, and opens the injector after a predetermined stop process to open the fuel A fuel cell system that introduces gas into the injector. The fuel cell system according to claim 3 or 4,
A plurality of the fuel supply sources;
The fuel cell system, wherein the supply gas is a fuel gas supplied from a lower temperature fuel supply source among the plurality of fuel supply sources. The fuel cell system according to any one of claims 3 to 5,
The injector is configured to drive an internal flow path that communicates between the upstream side and the downstream side, a valve body that is movably disposed in the internal flow path and changes the open / closed state of the flow path, and drives the valve body by energization. A valve body drive unit that
The said cooling mechanism is a fuel cell system which changes the electricity supply current to the said valve body drive part required for the movement of the opening direction of the said valve body according to the upstream pressure of the said injector. The fuel cell system according to any one of claims 3 to 6,
The injector is configured to drive an internal flow path that communicates between the upstream side and the downstream side, a valve body that is movably disposed in the internal flow path and changes the open / closed state of the flow path, and drives the valve body by energization. A valve body drive unit that
The said cooling mechanism is a fuel cell system which changes the energization current to the said valve body drive part required for hold | maintaining the open state of the said valve body according to a system state. The fuel cell according to any one of claims 1 to 3,
The cooling mechanism is a fuel cell system that opens the injector when a predetermined delay time elapses after receiving a system stop command. Stopping a fuel cell system comprising: a fuel cell; a fuel supply system for supplying fuel gas to the fuel cell; and an injector for adjusting a gas state upstream of the fuel supply system and supplying the fuel to a downstream side In the method
A method of stopping a fuel cell system comprising a step of cooling valve components in the injector when the system is stopped.

Images