JP2007200654A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system in which design flexibility is not restricted and responsiveness is not reduced, and moreover, a crew's unpleasantness due to noises can be reduced to a great extent. <P>SOLUTION: In the fuel cell system, in case a speed of a vehicle loading the fuel cell system is slower than a predetermined speed, or in case an air flow volume passing an air pressure regulating valve 4 regulating pressure of air used by a fuel cell 1 is more than a predetermined air flow volume, a minimum aperture of the air pressure regulating valve 4 is controlled to be more than a predetermined level, by a controller 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell system that can be mounted on, for example, a fuel cell vehicle.

  In recent years, instead of vehicles using an internal combustion engine such as an engine, an electric vehicle has been developed that travels by rotating a motor based on electric power supplied from an on-board battery.

  In such an electric vehicle, noises may be generated as the motor or the like is driven, and therefore various technologies relating to silent control have been proposed (see, for example, Patent Document 1 and Patent Document 2).

  Specifically, Patent Document 1 discloses an air-conditioning operation that is mounted on an electric vehicle and performs heat exchange between the refrigerant flowing through the refrigerant circuit and the vehicle interior air passing through the indoor heat exchanger. An air conditioner for an electric vehicle is disclosed. In particular, the air conditioner for an electric vehicle includes a rotation control means for controlling the rotation speed of a compressor motor provided in the refrigerant circuit in accordance with a set output of the air conditioning control, a vehicle speed sensor for detecting the vehicle speed, and the rotation speed of the compressor motor. The rotational speed of the compressor motor by driving the rotational control means via the rotational speed limiting means when the vehicle speed detected by the vehicle speed sensor is equal to or lower than the predetermined speed. Silent control means for performing a silent control operation for limiting the rotational speed to a certain number of revolutions or less is provided. Thereby, in this electric vehicle air conditioner, the air conditioning operation is performed while suppressing the generation of noise by the compressor motor of the air conditioning control in response to the case where the vehicle speed is less than the predetermined speed and the noise generated by the traveling motor is small. Therefore, it is said that it is possible to maintain a quiet state while keeping a decrease in the air conditioning capability due to the air conditioning control within an allowable range for the passenger in the vehicle interior.

Further, Patent Document 2 discloses an eccentric butterfly valve in which the seal surface between the valve body peripheral surface and the valve seat formed on the inner surface of the main body is eccentric from the center of the valve stem when fully closed. In particular, the eccentric butterfly valve is provided with protrusions on the valve body and the bore, and can suppress noise by suppressing cavitation that occurs when air passes.
JP-A-7-223428 JP 2002-195421 A

  By the way, in recent years, fuel gas containing a large amount of hydrogen is supplied to the fuel electrode (hydrogen electrode) of the fuel cell, and air as an oxidant gas is supplied to the air electrode. 2. Description of the Related Art Fuel cell systems that generate generated power by electrochemically reacting with oxygen are known. Such a fuel cell system is highly expected to be put into practical use, for example, as a power source for vehicles, and research and development for practical use are being actively conducted.

  In a fuel cell vehicle using such a fuel cell system using a fuel cell as a power source for the vehicle, not only a compressor for an air conditioner but also a pump for pumping a refrigerant for cooling various components, a fuel pressure, etc. are controlled. Valves and parts related to high electric power become noise generators, and noise may also be generated by a compressor that pumps air to the fuel cell. Therefore, the technology described in Patent Document 1 solves the problem of noise. I can't do it. Further, in the fuel cell vehicle, when the control pressure of the air pressure adjustment valve is high, airflow noise is generated at the pressure adjustment valve portion, which may be a problem.

  In addition, as a structure of the air pressure regulating valve, as in the technique described in Patent Document 2, a structure that suppresses cavitation generated when a fluid passes by providing protrusions on the valve body and the bore is adopted. However, there is a problem that the pressure loss of the fluid passing through the valve body is increased by the protrusions, and the design freedom of the fuel cell system is limited. Further, in a fuel cell vehicle, the provision of a protrusion on the valve body increases the mass of the valve body, leading to a decrease in opening responsiveness, resulting in a decrease in responsiveness of the fuel cell system. Therefore, there is a problem that it becomes impossible to respond to the driver's request. Furthermore, in a fuel cell vehicle, in order not to increase the pressure loss when the fluid passes through the valve body, it is necessary to enlarge the valve body, which causes problems such as deterioration in layout and an increase in mass. I was invited. The deterioration of the responsiveness may be prevented by increasing the torque of the valve driving actuator, but there is a problem that the actuator becomes larger and the power consumption increases.

  Accordingly, the present invention has been proposed in view of the above-described circumstances, and a fuel cell system that can greatly reduce the uncomfortable feeling of passengers due to noise without limiting the degree of freedom of design and reducing responsiveness. The purpose is to provide.

  In the fuel cell system according to the present invention, when the vehicle speed of a vehicle equipped with the fuel cell system is slower than a predetermined speed, the minimum opening of the air pressure regulating valve that regulates the pressure of air used by the fuel cell is set. By limiting to a predetermined opening or more, the above-mentioned problem is solved.

  Further, the fuel cell system according to the present invention has a minimum opening degree of the air pressure regulating valve when the flow rate of the air passing through the air pressure regulating valve for regulating the pressure of the air used by the fuel cell is larger than a predetermined flow rate. The above-mentioned problem is solved by limiting the above to a predetermined opening or more.

  Furthermore, the fuel cell system according to the present invention is configured such that the vehicle speed of a vehicle on which the fuel cell system is mounted is slower than a predetermined speed, and air that passes through an air pressure regulating valve that regulates the pressure of air used by the fuel cell. When the flow rate is higher than the predetermined flow rate, the above-described problem is solved by limiting the minimum opening degree of the air pressure regulating valve to a predetermined opening degree or more.

  In the fuel cell system according to the present invention, when the vehicle speed of a vehicle equipped with the fuel cell system is slower than a predetermined speed, or when the air passing through the air pressure regulating valve that regulates the pressure of the air used by the fuel cell is reduced. When the flow rate is higher than the predetermined flow rate, the minimum opening degree of the air pressure regulating valve is limited to the predetermined opening degree or more. It can be greatly reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In this embodiment, for example, a drive motor for driving the vehicle is generated by supplying electric power to a drive motor mounted on a fuel cell vehicle and an auxiliary machine that generates power from the fuel cell stack. It is a fuel cell system.

[First Embodiment]
First, the fuel cell system shown as the first embodiment will be described.

[Configuration of fuel cell system]
As shown in FIG. 1, the fuel cell system includes a fuel cell 1 that generates power using fuel gas and air. The fuel cell 1 is a main power source of the fuel cell system, and generates electricity by supplying a fuel gas containing a large amount of hydrogen for generating a power generation reaction and air as an oxidant gas containing oxygen. It is. Specifically, the fuel cell 1 includes an air electrode 1b to which an oxidant gas is supplied and a fuel electrode to which a fuel gas is supplied, with a heat medium 1a that cools heat generated inside the fuel cell 1 interposed therebetween. The fuel cell structure that is opposed to 1c is sandwiched between separators, and a plurality of cell structures are stacked.

  The fuel cell system also includes a compressor 2 that supplies air to the air electrode 1 b of the fuel cell 1, a pressure sensor 3 that detects the pressure of the air supplied to the fuel cell 1, and a supply to the air electrode 1 b of the fuel cell 1. An air pressure regulating valve 4 that regulates the pressure of the air, a vehicle speed sensor 5 that detects the vehicle speed of the fuel cell vehicle on which the fuel cell system is mounted, and a controller 10 that controls each part of the fuel cell system. Is provided.

  The compressor 2 is driven by a compressor motor (not shown) to take in outside air, and pumps air as an oxidant gas to the fuel cell 1 through the flow path L1. At this time, the compressor 2 is driven at a predetermined number of revolutions under the control of the controller 10 and discharges air as an oxidant gas at a necessary discharge flow rate.

  The pressure sensor 3 is provided between the compressor 2 and the fuel cell 1 in the flow path L1, and detects the pressure of the air flowing in the flow path L1. The pressure information detected by the pressure sensor 3 is supplied to the controller 10 electrically connected to the pressure sensor 3. In the present embodiment, the pressure sensor 3 is provided between the compressor 2 and the fuel cell 1 in the flow path L1, but the pressure between the compressor 2 and the air pressure regulating valve 4 is the same everywhere. Therefore, the pressure sensor 3 may be provided at any position between the compressor 2 and the air pressure regulating valve 4.

  The air pressure regulating valve 4 regulates the pressure of air used by the fuel cell 1. Specifically, the air pressure regulating valve 4 is provided downstream of the air electrode 1b in the flow path L2 connected to the air electrode 1b of the fuel cell 1, and its opening degree is controlled under the control of the controller 10. Is set to regulate the air pressure inside the air electrode 1b.

  The vehicle speed sensor 5 detects the vehicle speed of the fuel cell vehicle on which the fuel cell system is mounted. The vehicle speed information detected by the vehicle speed sensor 5 is supplied to the controller 10.

  In such a fuel cell system, the fuel cell 1 is controlled by controlling the rotation speed of the compressor 2 and the opening of the air pressure regulating valve 4 based on the detection result of the vehicle speed sensor 5 under the control of the controller 10. The flow rate of the air supplied to the air electrode 1b is controlled, and the power generation amount of the fuel cell 1 is controlled. In the fuel cell system, the electric power generated by the fuel cell 1 is supplied to the motor 6 that drives the fuel cell vehicle on which the fuel cell system is mounted.

  Here, the relationship between the opening degree of the air pressure regulating valve 4 and the noise generated by the air passing through the air pressure regulating valve 4 is as shown in FIG. That is, in the fuel cell system, when the flow rate of the air passing through the air pressure regulating valve 4 is smaller than the predetermined flow rate, the noise is small and not a problem, but the opening degree of the air pressure regulating valve 4 is larger than the predetermined opening degree. When the flow rate of air passing through the air pressure regulating valve 4 is smaller than a predetermined flow rate, a large noise is generated.

  Moreover, the relationship between the uncomfortable feeling given to the passengers by the generated noise and the vehicle speed of the fuel cell vehicle equipped with the fuel cell system is as shown in FIG. 3, for example. That is, in a fuel cell vehicle, when the vehicle speed is higher than a predetermined speed, it becomes difficult to hear other sounds due to running sounds such as tire sounds and wind noise during traveling, and the passengers feel less uncomfortable. On the other hand, in a fuel cell vehicle, when the vehicle speed is slower than a predetermined speed, it becomes easy to hear sounds other than the running sound, and the passenger feels uncomfortable.

  Therefore, in the fuel cell system, when the vehicle speed detected by the vehicle speed sensor 5 is slower than a predetermined speed, the minimum opening degree of the air pressure regulating valve 4 is limited to a predetermined opening degree or more to suppress the generation of noise. When the vehicle speed detected by the vehicle speed sensor 5 is faster than a predetermined speed, the controller 10 performs control so as to prohibit the restriction of the minimum opening of the air pressure regulating valve 4.

[Operation of fuel cell system]
Specifically, in the fuel cell system, the controller 10 controls the opening of the air pressure regulating valve 4 according to a series of procedures as shown in FIG.

  That is, as shown in the figure, when the controller 10 reads the vehicle speed VSP of the fuel cell vehicle detected by the vehicle speed sensor 5 in step S1, the minimum opening that is determined in advance corresponding to the vehicle speed VSP in step S2. The degree limit value PCVOL is read. The minimum opening limit value PCVOL is the minimum opening of the air pressure regulating valve 4 corresponding to the vehicle speed VSP so that the sound generated by the air passing through the air pressure regulating valve 4 does not give the passenger a sense of incongruity. These values are stored in a memory or the like so that they can be read out by the controller 10 in advance.

  Subsequently, in step S3, the controller 10 reads the air pressure regulating valve opening target value PCVO, which is the control target value of the air pressure regulating valve 4, and in step S4, the air pressure regulating valve opening target value PCVO is the minimum opening limit value. It is determined whether it is smaller than PCVOL.

  Here, when the controller 10 determines that the air pressure regulating valve opening target value PCVO is equal to or greater than the minimum opening limit value PCVOL, the controller 10 is in a state where the air pressure is controlled at an opening larger than the minimum opening, Therefore, the series of processing is terminated as it is without any limitation. On the other hand, if the controller 10 determines that the air pressure regulating valve opening target value PCVO is smaller than the minimum opening limit value PCVOL, there is a high possibility that noise will be generated and the passenger will feel uncomfortable. In the fourth embodiment, the opening of the air pressure regulating valve 4 is limited to the minimum opening restriction value PCVOL, and the air pressure regulating valve opening target value PCVO that is the opening of the air pressure regulating valve 4 before the restriction is described later. Therefore, the air pressure regulating valve opening target value PCVO is stored as the pre-restriction opening degree MMRPCVO, and the series of processes is terminated.

  In the fuel cell system, the opening degree of the air pressure regulating valve 4 can be optimally controlled according to the vehicle speed VSP by going through such a series of procedures.

[Effect of the first embodiment]
As described above in detail, in the fuel cell system shown as the first embodiment, when the vehicle speed VSP of the fuel cell vehicle on which the fuel cell system is mounted is slower than a predetermined speed, the controller 10 Under the control, the air pressure regulating valve 4 can be controlled so as to limit the minimum opening of the air pressure regulating valve 4 to a predetermined opening or more.

  That is, in this fuel cell system, when the vehicle is running at a low speed where the running sound of the vehicle cannot be ignored, the minimum opening degree of the air pressure regulating valve 4 is limited to a predetermined opening degree or more. Noise generated by the air passing through the air pressure regulating valve 4 can be reduced. At this time, in the fuel cell system, it is not necessary to make the structure of the air pressure regulating valve 4 special. Therefore, when the air passes through the valve body, the pressure loss due to the shape of the valve body is increased. It is not invited, and further, the design freedom of the fuel cell system is not limited. In the fuel cell system, for the same reason, the opening degree responsiveness of the air pressure regulating valve 4 is not lowered, and the responsiveness of the fuel cell system is not lowered. Further, in the fuel cell system, since the actuator is not increased in torque in order to improve the response, the power consumption is not increased. As described above, in this fuel cell system, the degree of freedom of design is not limited, and the opening degree responsiveness of the valve body is not lowered, and the occupant's uncomfortable feeling due to noise can be greatly reduced. .

  Further, in this fuel cell system, under the control of the controller 10, when the vehicle speed VSP is faster than a predetermined speed, restriction of the minimum opening of the air pressure regulating valve 4 is prohibited. As described above, in the fuel cell system, in a situation where the noise is canceled by the running sound, it is wasteful by setting the performance-oriented operation mode without limiting the opening of the air pressure regulating valve 4. A situation in which the vehicle performance is degraded can be avoided.

[Second Embodiment]
Next, a fuel cell system shown as a second embodiment of the present invention will be described.

  The fuel cell system shown as the second embodiment controls the opening of the air pressure regulating valve in accordance with the flow rate of air passing through the air pressure regulating valve. Therefore, in the description of the second embodiment, the same reference numerals are given to the same components as those in the fuel cell system shown as the first embodiment, and the description thereof is omitted.

[Configuration of fuel cell system]
As shown in FIG. 5, the fuel cell system includes a flow rate sensor 12 that detects the flow rate of air supplied to the compressor 2 instead of the vehicle speed sensor 5 in the fuel cell system shown as the first embodiment.

  The flow rate sensor 12 is provided upstream of the compressor 2 and detects the flow rate of air taken in by the compressor 2. The flow rate information detected by the flow sensor 12 is supplied to the controller 10 electrically connected to the flow sensor 12. In the present embodiment, the flow rate sensor 12 is provided upstream of the compressor 2. However, since the flow rate of air between the compressor 2 and the air pressure regulating valve 4 is the same everywhere, the flow rate sensor 12 may be provided at any position between the compressor 2 and the air pressure regulating valve 4.

  Here, in the fuel cell system, as shown in FIG. 2, when the flow rate of the air passing through the air pressure regulating valve 4 is smaller than the predetermined flow rate, the noise is small and this is not a problem. When the opening degree of the pressure valve 4 is smaller than the predetermined opening degree and the flow rate of the air passing through the air pressure regulating valve 4 is larger than the predetermined flow rate, a large noise is generated.

  Therefore, in the fuel cell system, when the air flow rate detected by the flow sensor 12 is higher than the predetermined flow rate, the minimum opening degree of the air pressure regulating valve 4 is limited to a predetermined opening degree or more to suppress the generation of noise. On the other hand, when the flow rate of air detected by the flow rate sensor 12 is smaller than the predetermined flow rate, the controller 10 performs control so as to prohibit the restriction of the minimum opening of the air pressure regulating valve 4.

[Operation of fuel cell system]
Specifically, in the fuel cell system, the controller 10 controls the opening degree of the air pressure regulating valve 4 according to a series of procedures as shown in FIG.

  That is, as shown in the figure, when the controller 10 reads the air pressure regulating valve passage flow rate Qav detected by the flow sensor 12 in step S11, the controller 10 determines in advance corresponding to the air pressure regulation valve passage flow rate Qav in step S12. The obtained minimum opening limit value PCVOL is read from a memory or the like.

  Subsequently, in step S13, the controller 10 reads the air pressure regulating valve opening target value PCVO, which is the control target value of the air pressure regulating valve 4, and in step S14, the air pressure regulating valve opening target value PCVO is the minimum opening limit value. It is determined whether it is smaller than PCVOL.

  Here, when the controller 10 determines that the air pressure regulating valve opening target value PCVO is equal to or greater than the minimum opening limit value PCVOL, the controller 10 is in a state where the air pressure is controlled at an opening larger than the minimum opening, Therefore, the series of processing is terminated as it is without any limitation. On the other hand, if the controller 10 determines that the air pressure regulating valve opening target value PCVO is smaller than the minimum opening limit value PCVOL, there is a high possibility that noise will be generated and the passenger will feel uncomfortable. In the fourth embodiment, the opening of the air pressure regulating valve 4 is limited to the minimum opening restriction value PCVOL, and the air pressure regulating valve opening target value PCVO that is the opening of the air pressure regulating valve 4 before the restriction is described later. Therefore, the air pressure regulating valve opening target value PCVO is stored as the pre-restriction opening degree MMRPCVO, and the series of processes is terminated.

  In the fuel cell system, the opening degree of the air pressure regulating valve 4 can be optimally controlled according to the air pressure regulating valve passage flow rate Qav through such a series of procedures.

[Effect of the second embodiment]
As described above in detail, in the fuel cell system shown as the second embodiment, when the air regulating valve passage flow rate Qav is larger than the predetermined flow rate, the air conditioning is controlled under the control of the controller 10. The air pressure regulating valve 4 can be controlled so as to limit the minimum opening of the pressure valve 4 to a predetermined opening or more.

  That is, in this fuel cell system, in a situation where the air pressure regulating valve passage flow rate Qav is large and noise is likely to occur, the air pressure regulating valve 4 is limited to a predetermined opening degree or more by limiting the minimum opening degree of the air pressure regulating valve 4. Noise generated by the air passing through the pressure regulating valve 4 can be reduced. At this time, in the fuel cell system, it is not necessary to make the structure of the air pressure regulating valve 4 special. Therefore, when the air passes through the valve body, the pressure loss due to the shape of the valve body is increased. It is not invited, and further, the design freedom of the fuel cell system is not limited. In the fuel cell system, for the same reason, the opening degree responsiveness of the air pressure regulating valve 4 is not lowered, and the responsiveness of the fuel cell system is not lowered. Further, in the fuel cell system, since the actuator is not increased in torque in order to improve the response, the power consumption is not increased. As described above, in this fuel cell system, the degree of freedom of design is not limited, and the opening degree responsiveness of the valve body is not lowered, and the occupant's uncomfortable feeling due to noise can be greatly reduced. .

  Further, in this fuel cell system, under the control of the controller 10, when the air pressure regulating valve passage flow rate Qav is smaller than a predetermined flow rate, restriction of the minimum opening degree of the air pressure regulating valve 4 is prohibited. As described above, in the fuel cell system, in a situation where it is difficult for noise to occur, the vehicle performance is unnecessarily degraded by setting the performance-oriented operation mode without limiting the opening of the air pressure regulating valve 4. Can be avoided.

[Third Embodiment]
Next, a fuel cell system shown as a third embodiment of the present invention will be described.

  The fuel cell system shown as the third embodiment controls the opening of the air pressure regulating valve according to both the vehicle speed of the fuel cell vehicle and the flow rate of air passing through the air pressure regulating valve. Therefore, in the description of the third embodiment, the same reference numerals are given to the same components as those in the fuel cell systems shown as the first embodiment and the second embodiment, and the description thereof is omitted. .

[Configuration of fuel cell system]
As shown in FIG. 7, the fuel cell system includes both a vehicle speed sensor 5 and a flow rate sensor 12.

[Operation of fuel cell system]
In such a fuel cell system, the controller 10 controls the opening degree of the air pressure regulating valve 4 according to a series of procedures as shown in FIG.

  First, as shown in the figure, the controller 10 reads the vehicle speed VSP detected by the vehicle speed sensor 5 and the air pressure regulating valve passage flow rate Qav detected by the flow rate sensor 12 in step S21.

  Subsequently, in step S22, for example, as shown in FIG. 9, the controller 10 reads from the memory or the like the minimum opening degree limit value PCVOL determined in advance corresponding to the vehicle speed VSP and the air pressure regulating valve passage flow rate Qav. Specifically, the minimum opening limit value PCVOL takes a larger value as the air pressure regulating valve passage flow rate Qav is larger and the vehicle speed VSP is lower. In the present embodiment, for convenience of explanation, when the minimum opening limit value PCVOL is equal to or smaller than a predetermined value, the minimum opening limit value PCVOL is set to 0, and the opening of the air pressure regulating valve 4 is not limited. To do.

  Subsequently, in step S23, the controller 10 reads the air pressure regulating valve opening target value PCVO, which is the control target value of the air pressure regulating valve 4, and in step S24, the air pressure regulating valve opening target value PCVO is the minimum opening limit value. It is determined whether it is smaller than PCVOL.

  Here, when the controller 10 determines that the air pressure regulating valve opening target value PCVO is equal to or greater than the minimum opening limit value PCVOL, the controller 10 is in a state where the air pressure is controlled at an opening larger than the minimum opening, Therefore, the series of processing is terminated as it is without any limitation. On the other hand, if the controller 10 determines that the air pressure regulating valve opening target value PCVO is smaller than the minimum opening limit value PCVOL, there is a high possibility that noise will be generated and the passenger will feel uncomfortable. In the fourth embodiment, the opening of the air pressure regulating valve 4 is limited to the minimum opening restriction value PCVOL, and the air pressure regulating valve opening target value PCVO that is the opening of the air pressure regulating valve 4 before the restriction is described later. Therefore, the air pressure regulating valve opening target value PCVO is stored as the pre-restriction opening degree MMRPCVO, and the series of processes is terminated.

  In the fuel cell system, the opening degree of the air pressure regulating valve 4 can be optimally controlled according to both the vehicle speed VSP and the air pressure regulating valve passage flow rate Qav through such a series of procedures.

[Effect of the third embodiment]
As described above in detail, in the fuel cell system shown as the third embodiment, the vehicle speed VSP of the fuel cell vehicle on which the fuel cell system is mounted is slower than a predetermined speed and passes through the air pressure regulating valve. When the flow rate Qav is larger than the predetermined flow rate, the air pressure regulating valve 4 can be controlled so as to limit the minimum opening degree of the air pressure regulating valve 4 to a predetermined opening degree or more under the control of the controller 10. . Therefore, in this fuel cell system, as in the first and second embodiments, the degree of freedom of design is not limited, and the opening degree responsiveness of the valve body can be reduced. In addition, the occupant's discomfort due to noise can be greatly reduced.

[Fourth Embodiment]
Next, a fuel cell system shown as a fourth embodiment of the present invention will be described.

  The fuel cell system shown as the fourth embodiment corrects a delay that occurs depending on whether or not the opening of the air pressure regulating valve is limited. Therefore, in the description of the fourth embodiment, the same reference numerals are given to the same components as those in the fuel cell systems shown as the first to third embodiments, and the description thereof is omitted. .

  First, the relationship between the operating pressure of the fuel cell 1 and time when the opening of the air pressure regulating valve 4 is not limited according to the flow rate of air supplied to the compressor 2 and / or the vehicle speed of the fuel cell vehicle is shown in FIG. The relationship is as shown by the solid line C1. On the other hand, the relationship between the operating pressure of the fuel cell 1 and time when the opening of the air pressure regulating valve 4 is limited according to the flow rate of air supplied to the compressor 2 and / or the vehicle speed of the fuel cell vehicle is shown in FIG. The relationship is as shown by the broken line C2. Further, the relationship between the operating pressure of the fuel cell 1 and the time to be set as a control target in consideration of the vehicle speed of the fuel cell vehicle is as shown by a solid line C3 in FIG. Here, comparing the rise of the solid line C1 and the broken line C2, it can be seen that the rise of the broken line C2 is delayed compared to the rise of the solid line C1.

  Further, when the opening degree of the air pressure regulating valve 4 is not limited according to the flow rate of air supplied to the compressor 2 and / or the vehicle speed of the fuel cell vehicle, the opening degree of the air pressure regulating valve 4 is supplied to the compressor 2. The generated power that can be generated by the fuel cell 1 when it is limited according to the air flow rate and / or the vehicle speed of the fuel cell vehicle has a relationship shown by a solid line C4 and a broken line C5 in FIG. 11, respectively. . Here, when the rising edges of the solid line C4 and the broken line C5 are compared, it can be seen that the rising edge of the broken line C5 is delayed compared to the rising edge of the solid line C4.

  In FIG. 12, regarding the relationship between the opening degree of the air pressure regulating valve 4 and the time corresponding to FIGS. 10 and 11, a case where the opening degree of the air pressure regulating valve 4 is not limited is indicated by a solid line C <b> 6. A case where the opening degree is limited is indicated by a broken line C7.

  Thus, in the fuel cell system, the response of the generated power of the fuel cell 1 is delayed depending on whether the opening of the air pressure regulating valve 4 is limited, and the flow rate of air detected by the flow sensor 12 is There is a case where the actual air flow rate actually passing through the air pressure regulating valve 4 is not reached. In the fuel cell system, as the response of the generated power of the fuel cell 1 is delayed, the power required for the motor 6 driven by the power supplied from the fuel cell 1 becomes insufficient, and the fuel cell This will interfere with vehicle travel.

[Configuration of fuel cell system]
Therefore, in the fuel cell system shown as the fourth embodiment, the actual air actually passing through the air pressure regulating valve 4 is used for the air flow rate detected by the flow rate sensor 12 in order to prevent such an adverse effect. A device for correcting the flow rate and a secondary battery for supplying electric power to the motor 6 are provided.

  Specifically, as shown in FIG. 13, the fuel cell system detects the secondary battery 14 and the remaining capacity of the secondary battery 14 in addition to the configuration of the fuel cell system shown as the third embodiment. A remaining capacity sensor 16, a power control unit 18 that controls a power supply source and a power supply destination, and an accelerator sensor 20 that detects an accelerator opening of a fuel cell vehicle (not shown).

  When the power generation amount of the fuel cell 1 is insufficient, the secondary battery 14 supplies the motor 6 with insufficient power in the fuel cell 1 under the control of the power control unit 18 by a method described later.

  The remaining capacity sensor 16 detects the remaining capacity of the secondary battery 14. The remaining capacity of the secondary battery 14 detected by the remaining capacity sensor 16 is supplied to the controller 10.

  The power control unit 18 switches between a power supply source and a power supply destination under the control of the controller 10. Specifically, when the power control unit 18 stores the power generated by the fuel cell 1, the power control unit 18 supplies the power to the secondary battery 14 and charges it while driving the motor 6. The power supply source and the supply destination are switched so that the power is supplied to the motor 6. In addition, the power control unit 18 discharges the power charged in the secondary battery 14 and supplies it to the motor 6 under the control of the controller 10. For example, in a situation where the power supplied to the motor 6 is only the power supplied from the fuel cell 1, the controller 10 determines that the power required by the motor 6 cannot be supplied with the power generation amount of only the fuel cell 1. If so, the power control unit 18 is notified accordingly. Then, based on the notification, the power control unit 18 discharges the power charged in the secondary battery 14 and supplies it to the motor 6 to compensate for the shortage of the fuel cell 1.

  The accelerator sensor 20 detects the opening of an accelerator (not shown) by the driver's operation. The accelerator opening information detected by the accelerator sensor 20 is supplied to the controller 10.

  Such a fuel cell system is functionally configured as shown in FIG. That is, in the fuel cell system, the flow rate information detected by the flow rate sensor 12 is supplied to the delay correction unit 10 a in the controller 10. In response to this, the delay correction unit 10a corrects the delay based on the flow rate information, so that the flow rate of the air detected by the flow rate sensor 12 is actually passed through the air pressure regulating valve 4. A correction value for correcting the flow rate is calculated, and the calculated correction value is supplied to the opening degree restriction execution determination unit 10b. At the same time, in the fuel cell system, the vehicle speed information detected by the vehicle speed sensor 5 is supplied to the opening restriction execution determination unit 10b.

  Based on the flow rate information supplied from the flow sensor 12 and the correction value supplied from the delay correction unit 10a, the opening limit execution determination unit 10b determines whether or not the opening of the air pressure regulating valve 4 should be limited. When the opening degree restriction execution determination unit 10b determines that the opening degree of the air pressure regulating valve 4 should be restricted, the opening degree restriction unit 10c restricts the opening degree of the air pressure regulating valve 4. At this time, the opening degree restriction execution determination unit 10b determines whether or not the power supplied to the motor 6 is insufficient, and if it is determined that the power supplied to the motor 6 is insufficient, the power assist unit 10d The electric power charged in the secondary battery 14 is discharged and supplied to the motor 6.

[Operation of fuel cell system]
Such a fuel cell system performs the following operations.

  First, in the fuel cell system, a corrected air flow rate Qav which is an air pressure regulating valve passage flow rate corrected according to a series of procedures as shown in FIG. 15 is obtained by the delay correction unit 10a.

  That is, as shown in the figure, the delay correction unit 10a, in step S31, as the information necessary for calculating the correction value, the target pressure value Pt, the target flow rate Qat, the pressure sensor stored in advance in a memory or the like. The current pressure value P detected by 3 and the current flow rate Qa detected by the flow sensor 12 are read. Here, the target pressure value Pt is the most suitable operating pressure value of the fuel cell 1 in the current situation considering the vehicle speed of the fuel cell vehicle. Further, the target flow rate Qat is a flow rate of air taken into the most suitable compressor 2 in the same situation. Of the values read here, at least the current flow rate Qa is sequentially stored in a memory or the like under the control of the controller 10.

  When these values are read, the delay correction unit 10a reads the delay time Td in step S32. The delay time Td can be determined according to the difference between the current situation considering the vehicle speed of the fuel cell vehicle and the most suitable situation to be targeted. For example, as shown in FIG. 16, the delay time Td shows a smaller value as the difference between the target flow rate Qat and the current flow rate Qa and the difference between the target pressure value Pt and the current pressure value P are smaller. On the other hand, the delay time Td shows a larger value as the difference between the target flow rate Qat and the current flow rate Qa and the difference between the target pressure value Pt and the current pressure value P are larger.

  Subsequently, in step S33, the delay correction unit 10a reads the air flow rate Qa (Td), which is a correction value, based on the delay time Td. The air flow rate Qa (Td) read here is the air flow rate Qa at the time before the delay time Td from the current time.

  In step S34, the delay correction unit 10a stores the air flow rate Qa (Td) in the memory or the like as the corrected air flow rate Qav, and ends the series of processes.

  In the fuel cell system, the corrected air flow rate Qav, which is the corrected air pressure regulating valve passage flow rate, can be obtained through such a series of procedures. In the fuel cell system, when the corrected air flow rate Qav is obtained, the opening degree restriction execution determination unit 10b and the opening degree restriction unit 10c replace the air pressure regulating valve passage flow rate in the series of processes shown in FIG. By performing the process using the corrected air flow rate Qav, the opening degree of the air pressure control valve 4 can be optimally controlled according to both the vehicle speed VSP and the air pressure control valve passage flow rate Qav.

  Next, the operation of the power assist unit 10d will be described with reference to FIG.

  As shown in the figure, the power assist unit 10d resets the battery assist power value Pb to 0, which is an initial value, in step S41. The battery assist power value Pb is a value indicating the power supplied from the secondary battery 14 to the motor 6 via the power control unit 18.

  Subsequently, when the power assist unit 10d reads the remaining capacity SOC of the secondary battery 14 using the remaining capacity sensor 16 in step S42, the remaining capacity SOC is compared with the remaining capacity threshold SOCSL in step S43. Note that the remaining capacity threshold value SOCSL is a value stored in advance in a memory or the like, and serves as a guideline for determining whether or not the power charged in the secondary battery 14 can be supplied to the motor 6. It is.

  Here, when the power assist unit 10d determines that the battery remaining capacity SOC is smaller than the remaining capacity threshold SOCSL, the motor 6 requests in the current state where the opening of the air pressure regulating valve 4 is limited. The fuel cell 1 and the secondary battery 14 are determined not to be able to supplement the power that is present, and the process proceeds to step S44. Then, in step S44, the power assist unit 10d performs a process for prohibiting the restriction of the minimum opening of the air pressure regulating valve 4. Specifically, the power assist unit 10d prohibits the restriction of the opening of the air pressure adjustment valve 4 by setting the pre-restriction opening MMRPCVO stored in the memory or the like to the air pressure adjustment valve opening target value PCVO. A series of processing ends.

  On the other hand, if the power assist unit 10d determines that the battery remaining capacity SOC is larger than the remaining capacity threshold SOCSL, the motor 6 requests the current pressure regulation valve 4 even in the current state where the opening degree of the air pressure regulating valve 4 is limited. It is determined that it is possible to compensate for the shortage of power that is being charged with the power charged in the secondary battery 14, and the process proceeds to step S45. In step S45, the power assist unit 10d performs a process for supplying from the secondary battery 14 the power shortage requested by the motor 6. Specifically, the power assist unit 10d reads the power requirement value Pr and the fuel cell power generation amount Pfc stored in the memory or the like. Here, the required power value Pr is a value calculated based on the accelerator opening detected by the accelerator sensor 20 and stored in a memory or the like, so that the motor 6 does not interfere with the fuel cell vehicle. This is a value indicating the driving power required to drive the motor. The fuel cell power generation amount Pfc is a value indicating the power that the fuel cell 1 is currently generating.

  Subsequently, in step S46, the power assist unit 10d calculates a power supply amount Pd to be supplied from the secondary battery 14 to the motor 6 based on the power requirement value Pr and the fuel cell power generation amount Pfc. The power supply amount Pd can be calculated by obtaining the difference between the power requirement value Pr and the fuel cell power generation amount Pfc.

  Then, in step S47, the power assist unit 10d sets the battery assist power value Pb as the power supply amount Pd in order to supply the power charged in the secondary battery 14 to the motor 6, and ends the series of processes. In response to this, the electric power control unit 18 discharges the electric power charged in the secondary battery 14 by the battery assist electric power value Pb and supplies it to the motor 6.

  In the fuel cell system, the corrected air flow rate Qav, which is the corrected air pressure adjustment valve passage flow rate, is obtained through such a series of procedures, and the air flow is adjusted according to both the vehicle speed VSP and the air pressure adjustment valve passage flow rate Qav. While the opening degree of the pressure regulating valve 4 is optimally controlled, electric power can be supplied from the secondary battery 14 when the electric power required by the motor 6 is insufficient.

  In the fuel cell system, the above-described delay time Td is predicted by advanced control such as, for example, modeling the system volume, the capacity of the compressor 2, and the like to predict the flow rate of air passing through the air pressure regulating valve 4. You may decide to go.

  In the fuel cell system, the flow rate sensor 12 is not used to detect the flow rate. For example, when the positive displacement compressor 2 is used, the rotational speed is substantially proportional to the flow rate. The flow rate may be predicted based on the output of the rotation speed sensor that detects the rotation speed of the compressor 2. Further, in the fuel cell system, when the centrifugal compressor 2 is used, the relationship between the rotational speed and the flow rate cannot be predicted linearly as in the positive displacement type. Since it is possible to predict the flow rate based on the pressure, such a map may be used to predict the flow rate.

[Effect of the fourth embodiment]
As described above in detail, in the fuel cell system shown as the fourth embodiment, the flow rate of the air detected by the flow sensor 12 is actually passed through the air pressure regulating valve 4 by the delay correction unit 10a. If it is not the actual air flow rate, the correction is made to the actual air flow rate, and the opening of the air pressure regulating valve 4 is controlled based on the actual air flow rate that is the calculated correction value.

  That is, the air flow rate to the fuel cell 1 may be detected at the inlet of the fuel cell 1 or may be predicted based on the rotational speed or control pressure of the compressor 2 or a blower (not shown). The flow rate of air passing through the air pressure regulating valve 4 is generally delayed with respect to these detected or predicted values. Therefore, in this fuel cell system, by controlling the opening degree of the air pressure regulating valve 4 in consideration of this delay, it is possible to effectively suppress noise that is actually generated, and to further improve sound performance. Can do.

  Further, in this fuel cell system, when the amount of power generated by the fuel cell 1 is insufficient by the power assist unit 10d, the power for the shortage is compensated by discharging the power charged in the secondary battery 14. Thus, the shortage of power due to the delay can be effectively compensated, and it is possible to eliminate the feeling of strangeness due to the shortage of power to the occupant.

  Further, in this fuel cell system, when the battery remaining capacity SOC of the secondary battery 14 is smaller than a predetermined remaining capacity threshold SOCSL, the power assist unit 10d prohibits the restriction on the minimum opening of the air pressure regulating valve 4. To do. Thus, in the fuel cell system, if the secondary battery 14 cannot compensate for the shortage of the power generation amount of the fuel cell 1, it gives the passenger an unacceptable sense of incongruity due to power shortage. By prohibiting the restriction of the minimum opening of the air pressure regulating valve 4 so as not to cause a power shortage even if the generation of noise is allowed, the uncomfortable feeling given to the occupant can be minimized.

  The above-described embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and even if it is a form other than this embodiment, as long as it does not depart from the technical idea according to the present invention, the design and the like Of course, various modifications are possible.

It is a figure explaining the structure of the fuel cell system shown as the 1st Embodiment of this invention. It is a figure explaining the relationship between the opening degree of an air pressure regulation valve, and the noise which generate | occur | produces with the air which passes the said air pressure regulation valve. It is a figure explaining the relationship between the discomfort which the noise which generate | occur | produces gives to a passenger | crew, and the vehicle speed of the fuel cell vehicle carrying a fuel cell system. In the fuel cell system shown as a 1st embodiment of the present invention, it is a flow chart explaining a series of processings at the time of controlling the opening of an air pressure regulation valve. It is a figure explaining the structure of the fuel cell system shown as the 2nd Embodiment of this invention. 7 is a flowchart illustrating a series of processes when controlling the opening of an air pressure regulating valve in a fuel cell system shown as a second embodiment of the present invention. It is a figure explaining the structure of the fuel cell system shown as the 3rd Embodiment of this invention. 7 is a flowchart illustrating a series of processes when controlling the opening of an air pressure regulating valve in a fuel cell system shown as a third embodiment of the present invention. It is a figure explaining the minimum opening degree limit value determined corresponding to the vehicle speed and the air pressure regulation valve passage flow rate. It is a figure explaining the relationship between the operating pressure of fuel cell, and time. It is a figure explaining the relationship between the generated electric power which can be generated with a fuel cell, and time. It is a figure explaining the relationship between the opening degree of an air pressure regulation valve, and time. It is a figure explaining the structure of the fuel cell system shown as the 4th Embodiment of this invention. It is a block diagram explaining the functional structure of the fuel cell system shown as the 4th Embodiment of this invention. 10 is a flowchart illustrating a series of processes when obtaining a corrected air flow rate in the fuel cell system shown as the fourth embodiment of the present invention. It is a figure explaining the delay time according to the difference of a target flow rate and the present flow rate, and the difference of a target pressure value and the present pressure value. 10 is a flowchart illustrating a series of processes performed by a power assist unit in a fuel cell system shown as a fourth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell 1a Heat medium 1b Air electrode 1c Fuel electrode 2 Compressor 3 Pressure sensor 4 Air pressure regulating valve 5 Vehicle speed sensor 6 Motor 10 Controller 10a Delay correction | amendment part 10b Opening restriction implementation determination part 10c Opening restriction part 10d Electric power assist part 12 Flow volume Sensor 14 Secondary battery 16 Remaining capacity sensor 18 Power control unit 20 Acceleration sensor MMRPCVO Opening before limit P Current pressure Pb Battery assist power value PCVO Air pressure regulating valve opening target value PCVOL Minimum opening limit value Pfc Fuel cell power generation amount Pr Power Required value Pt Target pressure value Qa Current flow rate Qa (Td) Air flow rate Qat Target flow rate Qav Air pressure regulating valve passage flow rate SOC Remaining capacity SOCSL Remaining capacity threshold value Td Delay time VSP Vehicle speed

Claims (11)

A fuel cell that generates electricity using fuel gas and air;
Air supply means for supplying the air to the fuel cell;
An air pressure regulating valve that regulates the pressure of the air discharged from the air supply means and used by the fuel cell;
Vehicle speed detection means for detecting the vehicle speed of a vehicle equipped with the fuel cell system;
Control means for controlling the air pressure regulating valve so as to limit the minimum opening of the air pressure regulating valve to a predetermined opening or more when the vehicle speed detected by the vehicle speed detecting means is slower than the predetermined speed. A fuel cell system. A fuel cell that generates electricity using fuel gas and air;
Air supply means for supplying the air to the fuel cell;
An air pressure regulating valve that regulates the pressure of the air discharged from the air supply means and used by the fuel cell;
Flow rate detection / prediction means for detecting or predicting the flow rate of air passing through the air pressure regulating valve;
When the flow rate of air detected or predicted by the flow rate detection / prediction unit is higher than a predetermined flow rate, the air pressure control valve is controlled so as to limit the minimum opening of the air pressure control valve to a predetermined opening or more. And a control means. A fuel cell that generates electricity using fuel gas and air;
Air supply means for supplying the air to the fuel cell;
An air pressure regulating valve that regulates the pressure of the air discharged from the air supply means and used by the fuel cell;
Vehicle speed detection means for detecting the vehicle speed of a vehicle equipped with the fuel cell system;
Flow rate detection / prediction means for detecting or predicting the flow rate of air passing through the air pressure regulating valve;
When the vehicle speed detected by the vehicle speed detecting means is slower than a predetermined speed and the air flow rate detected or predicted by the flow rate detecting / predicting means is larger than the predetermined flow rate, the air pressure regulating valve is minimum opened. And a control means for controlling the air pressure regulating valve so as to limit the degree to a predetermined opening or more. 2. The control device according to claim 1, wherein when the vehicle speed of the vehicle detected by the vehicle speed detection device is higher than a predetermined speed, the control device prohibits the restriction of the minimum opening of the air pressure regulating valve. Item 4. The fuel cell system according to Item 3. The control means prohibits the restriction of the minimum opening of the air pressure regulating valve when the flow rate of the air detected or predicted by the flow rate detection / prediction means is smaller than a predetermined flow rate. The fuel cell system according to claim 2 or claim 3. When the flow rate of the air detected or predicted by the flow rate detection / prediction unit is not an actual air flow rate actually passing through the air pressure regulating valve, a correction unit that corrects the actual air flow rate is provided.
4. The fuel cell system according to claim 2, wherein the control unit controls an opening of the air pressure regulating valve based on the actual air flow rate that is a correction value calculated by the correction unit. 5. . A secondary battery,
The power assist means for supplementing the shortage of electric power by discharging the power charged in the secondary battery when the power generation amount of the fuel cell is insufficient. 7. The fuel cell system according to any one of items 6. 8. The fuel cell according to claim 7, wherein the power assisting unit prohibits the restriction of the minimum opening of the air pressure regulating valve when a remaining battery capacity of the secondary battery is smaller than a predetermined threshold value. system. Detect the vehicle speed of the vehicle equipped with the fuel cell system,
When the detected vehicle speed is slower than a predetermined speed, the air discharged from the air supply means for supplying the air to the fuel cell that generates power using fuel gas and air and used by the fuel cell. A fuel cell system, wherein the air pressure regulating valve is controlled so as to limit a minimum opening of the air pressure regulating valve for regulating pressure to a predetermined opening or more. A flow rate of air discharged from an air supply means for supplying air to a fuel cell that generates power using fuel gas and air and passing through an air pressure regulating valve that regulates the pressure of the air used by the fuel cell Detect or predict
When the detected or predicted flow rate of air is greater than a predetermined flow rate, the fuel pressure control system controls the air pressure control valve so as to limit the minimum opening of the air pressure control valve to a predetermined opening or more. . Detect the vehicle speed of the vehicle equipped with the fuel cell system,
A flow rate of air discharged from an air supply means for supplying air to a fuel cell that generates power using fuel gas and air and passing through an air pressure regulating valve that regulates the pressure of the air used by the fuel cell Detect or predict
When the detected vehicle speed is slower than the predetermined speed and the detected or predicted air flow rate is higher than the predetermined flow rate, the air pressure adjustment valve is configured to limit the minimum opening degree of the air pressure adjustment valve to a predetermined opening degree or more. A fuel cell system characterized by controlling a pressure valve.

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