JP5880009B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system.

  For example, a fuel cell system mounted on a vehicle such as an automobile supplies a fuel gas such as hydrogen and an oxidant gas such as air to the fuel cell, and uses the electric power generated by these electrochemical reactions as a load such as a drive motor. It is a power generation system to supply to The fuel gas is supplied to the fuel cell through a pipe connected to a fuel supply source such as a fuel tank and the fuel cell.

  The required flow rate of the fuel gas supplied to the fuel cell changes according to the electric power generated by the fuel cell. In order to perform efficient power generation, the flow rate of the fuel gas supplied to the fuel cell is increased when the required power of the load is large, and conversely the fuel supplied to the fuel cell when the required power of the load is small. It is desirable to reduce the gas flow rate. For this reason, a flow rate adjusting means for adjusting the flow rate of the fuel gas is disposed in the pipe connecting the fuel supply source and the fuel cell.

  As such a flow rate adjusting means, an injector is generally used. The injector is an electromagnetically driven on-off valve. When an electric current is supplied, the valve body is separated from the valve seat to open the flow path, while when the current supply is stopped, the valve body is moved to the valve seat. To close the flow path. In a fuel cell system using such an injector, the valve body of the injector is opened and closed so as to repeat the separation from the valve seat and the contact with the valve seat at a predetermined cycle. Supply is made. The flow rate of the fuel gas passing through the injector is adjusted by appropriately changing the period.

  When changing the injector from the closed state to the open state, it is necessary to supply a current for moving the valve body by electromagnetic force to the injector. Further, even after the valve body moves and the injector is opened, it is necessary to continue supplying current to the injector in order to maintain the opened state.

  The current required to bring the injector from the closed state to the open state is greater than the current required to keep the injector open. Therefore, when opening the injector, a relatively large current (rush current) is first supplied for a short time to move the valve body to the open position, and thereafter a relatively small current (holding current) is supplied. Thus, the valve body is held in the open position. By switching between the inrush current and the holding current, the power required for the operation of the injector can be reduced.

  For this reason, the control unit for supplying current to the injector and controlling its operation appropriately switches between two types of current consisting of a rush current that is a relatively large current and a holding current that is a current smaller than the rush current. Need to be supplied to the injector. As described above, the following two configurations are conceivable as the configuration of the control unit for supplying currents having different magnitudes.

  In the first configuration (hereinafter referred to as a chopper control configuration), two current paths that can be switched by a switch or the like are provided in parallel on a circuit that supplies current from a power source such as a battery to an injector. One current path includes a switching element and a current detection unit for detecting the magnitude of the current flowing through the current path.

  In this chopper control configuration, when supplying an inrush current, a switch or the like is switched to a current path where no switching element is arranged, and a large inrush current is supplied from the power source to the injector.

  On the other hand, when supplying the holding current, a switch or the like is switched to the current path in which the switching element is arranged, and the switching element is switched at an appropriate cycle so that the current detected by the current detection unit becomes a predetermined magnitude. So-called chopper control is performed in which the opening / closing operation is repeated at high speed. By performing such control, a relatively small holding current is supplied from the power source to the injector.

  In the second configuration (hereinafter referred to as a voltage dividing resistor configuration), two current paths that can be switched by a switch or the like are provided in parallel with each other on a circuit that supplies current from a power source such as a battery to an injector. This point is the same as the above-described chopper control configuration, but the present configuration is different in that one current path is provided with a voltage dividing resistor instead of a switching element.

  In this voltage dividing resistor configuration, when supplying an inrush current, a switch or the like is switched to the current path where the voltage dividing resistor is not arranged, and a large inrush current is supplied from the power source to the injector.

  On the other hand, when supplying the holding current, a switch or the like is switched to the current path where the voltage dividing resistor is arranged, and the current is supplied to the injector through this current path. Since the circuit that supplies the holding current to the injector is a circuit in which the injector and the voltage dividing resistor are connected in series, the resistance of the entire circuit increases. As a result, a relatively small holding current is supplied from the power source to the injector.

  Patent Document 1 described below describes a fuel cell system including a plurality of injectors arranged in parallel with each other in a flow path for supplying fuel gas from a fuel gas tank as a fuel supply source to the fuel cell. By adopting such a configuration, for example, control is performed so that the number of injectors through which the fuel gas is allowed to pass through by opening and closing the valve body is appropriately changed based on the required power, and the fuel gas is supplied to the fuel cell. The amount can be adjusted in a wide range. Therefore, in the fuel cell system having the configuration described in Patent Document 1 below, in order to individually control the operations of the plurality of injectors, it is necessary to provide the control units as described above for the plurality of injectors. is there.

JP 2010-054035 A

  Here, when the plurality of control units provided for the plurality of injectors have the above-described chopper control configuration, the following problem occurs. The chopper control configuration controls the holding current supplied to the injector by the high-speed switching operation of the switching element. However, the pulsation caused by the switching operation of the switching element occurs in the holding current. It is necessary to provide a noise filter circuit. Since the noise filter circuit is composed of a large number of components such as capacitors, the size of the control unit is increased.

  When the control device is configured by a plurality of control units corresponding to the number of injectors, the influence of the increase in size as described above is integrated, so that the volume occupied by the control device in the fuel cell system becomes enormous. In addition, since the switching element generates heat during operation, it is necessary to provide a heat dissipation mechanism. However, the provision of the heat dissipation mechanism further increases the size of the control device. In addition to these, there is a problem that the cost increases as the number of parts increases.

  Therefore, it is conceivable that the plurality of control units provided for the plurality of injectors have a voltage dividing resistor configuration instead of a chopper control configuration. However, as described above, the voltage dividing resistor configuration increases the resistance of the circuit by the voltage dividing resistor and supplies a small holding current to the injector. Therefore, useless energy consumption due to the current passing through the voltage dividing resistor. It is accompanied by. For this reason, wasteful energy consumption always occurs while the injector is in the open state. Further, such wasteful energy consumption occurs in each of the plurality of control units, so that the energy consumption cannot be ignored in the entire fuel cell system, and the fuel utilization efficiency is remarkably deteriorated.

  The present invention has been made in view of such problems, and an object of the present invention is to control the operation of a plurality of injectors while suppressing an increase in the size of the control device and suppressing an increase in power consumption. It is to provide a fuel cell system.

  In order to solve the above problems, a fuel cell system according to the present invention includes a fuel cell that receives supply of a fuel gas and an oxidant gas and generates power by an electrochemical reaction between the fuel gas and the oxidant gas, and the fuel cell. A first fuel flow path that is a flow path for supplying the fuel gas, and a flow path for supplying the fuel gas to the fuel cell, the second fuel flow being arranged in parallel with the first fuel flow path A first injector that switches between an open state and a closed state of the first fuel flow path, and a drive that is driven by the current supply to open the second fuel flow path And a second control for maintaining the first fuel flow path in an open state by setting a magnitude of a first current supplied to the first injector to a first predetermined value. And the second injector A second control unit that maintains the second fuel flow path in an open state by setting the magnitude of the second current to be a second predetermined value, the first control unit includes: A first power supply unit that is a supply source of the first current, and a circuit for supplying the first current from the first power supply unit to the first injector, and a first switch unit that switches between opening and closing the circuit A first circuit having a first circuit, and a chopper control that repeats the opening and closing operation of the first switch unit at a high speed, thereby setting the magnitude of the first current to the first predetermined value, The second control unit is a circuit for supplying the second current from the second power supply unit to the second injector, the second power supply unit being a supply source of the second current, In the second switch section that switches opening and closing and the circuit A second circuit having a voltage dividing resistor connected in series with the second injector, and by closing the second switch unit and closing the second circuit, The size is the second predetermined value.

  In the present invention, a first fuel flow path and a second fuel flow path that are fuel gas flow paths arranged in parallel to each other are provided, and the first fuel flow path is switched between an open state and a closed state. An injector and a second injector for switching between an open state and a closed state of the second fuel flow path are provided. Moreover, the 1st control part and the 2nd control part which each control operation | movement of these injectors are provided.

  The first control unit is a circuit for supplying a first current from the first power supply unit to the first injector, the first circuit having a first switch unit for switching opening and closing of the circuit Have The first control unit performs chopper control that repeatedly opens and closes the first switch unit at a high speed, thereby setting the first current flowing in the first injector to a first predetermined value and opening the first fuel flow path. To maintain. That is, the first control unit has the above-described chopper control configuration.

  The second control unit is a circuit for supplying a second current from the second power source unit to the second injector from the second power source unit, and a second switch unit for switching opening and closing of the circuit and a second switch unit in the circuit And a second circuit having a voltage dividing resistor connected in series with the injector. The second control unit closes the second switch unit and closes the second circuit, thereby setting the second current flowing in the second injector to a second predetermined value and opening the second fuel flow path. To maintain. That is, the second control unit has the above-described voltage dividing resistor configuration.

  That is, in the present invention, the first fuel flow path (and the first injector) maintained in the open state by the first control unit having the chopper control configuration and the second control unit having the voltage dividing resistance configuration are maintained in the open state. A second fuel flow path (and a second injector). The operation of the two injectors is not controlled by the control unit having the same configuration (chopper control configuration or voltage dividing resistor configuration), but is controlled by control units having different configurations.

  For this reason, compared with the case where all the control parts are made into a chopper control configuration, the apparatus can be miniaturized and the number of parts can be further reduced. In addition, it is possible to suppress generation of useless power consumption caused by current passing through the voltage dividing resistors, compared to a case where all the control units are configured as voltage dividing resistors.

  Further, in the fuel cell system according to the present invention, the amount of electric power generated by the fuel cell is controlled based on the required power from the load, and when the required power is a predetermined value or less, the first It is also preferable that the two injectors are always closed and the fuel gas is supplied to the fuel cell only from the first fuel flow path.

  In this preferred embodiment, when the required power from the load is less than or equal to the predetermined value, the second injector is always closed, and the fuel gas is supplied to the fuel cell only from the first fuel flow path. That is, the fuel gas is supplied to the fuel cell preferentially from the first fuel flow path, and the fuel gas is supplied from the second fuel flow path only when the required power is larger than a predetermined value. As a result, the frequency at which the second fuel flow path is opened, that is, the frequency at which the holding current is supplied to the second injector to maintain the open state is reduced, and therefore, the current is consumed when the current passes through the voltage dividing resistor. Energy is reduced. As a result, the fuel utilization efficiency in the fuel cell system can be further improved.

  The fuel cell system according to the present invention includes a plurality of the first injectors connected in parallel with each other in the first fuel flow path, and a plurality of the first injectors corresponding to the first injectors. It is also preferable to have a first control unit.

  In this preferred embodiment, a plurality of first injectors connected in parallel to each other are provided, and the operation of each first injector can be individually controlled. For this reason, the number of first injectors that allow the fuel gas to pass through by opening and closing the valve body is controlled based on the required power, and the amount of fuel gas supplied to the fuel cell is adjusted over a wide range. can do.

  The fuel cell system according to the present invention further includes a plurality of the second injectors connected in parallel to each other in the second fuel flow path, and a plurality of the second injectors corresponding to the second injectors. It is also preferable to include a second control unit.

  In this preferred embodiment, a plurality of second injectors connected in parallel to each other are provided, and the operation of each of the second injectors can be individually controlled. For this reason, the number of second injectors that allow the fuel gas to pass through by opening and closing the valve body is appropriately controlled based on the required power, and the amount of fuel gas supplied to the fuel cell is adjusted over a wide range. can do.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel cell system which can control operation | movement of a several injector can be provided, suppressing the enlargement of a control apparatus and suppressing the increase in power consumption.

It is the figure which showed the structure of the fuel cell system which is one Embodiment of this invention. It is the figure which showed the structure of a part of control apparatus of the fuel cell system shown in FIG. It is the figure which showed the structure of a part of control apparatus of the fuel cell system shown in FIG. 2 is a graph showing a change with time of current supplied to an injector in the fuel cell system shown in FIG. 1. 2 is a graph showing a change with time of current supplied to an injector in the fuel cell system shown in FIG. 1.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

  FIG. 1 is a diagram showing a configuration of a fuel cell system 10 according to an embodiment of the present invention. The fuel cell system 10 functions as, for example, an in-vehicle power supply system mounted on a fuel cell vehicle, and includes a fuel cell stack 20 that generates power upon receiving a supply of a reaction gas (fuel gas, oxidant gas), an oxidant An oxidant gas supply system 30 for supplying air as gas to the fuel cell stack 20, a fuel gas supply system 40 for supplying hydrogen gas as fuel gas to the fuel cell stack 20, and overall control of the entire system And a control device CTR.

  The fuel cell stack 20 is a solid polymer electrolyte cell stack formed by stacking a large number of cells in series. In the fuel cell stack 20, the oxidation reaction of the formula (1) occurs at the anode electrode, and the reduction reaction of the equation (2) occurs at the cathode electrode. In the fuel cell stack 20 as a whole, the electromotive reaction of the formula (3) occurs.

H2 → 2H ++ 2e- (1)
(1/2) O2 + 2H ++ 2e-> H2O (2)
H2 + (1/2) O2 → H2O (3)

  The oxidant gas supply system 30 includes an oxidant gas flow path 33 through which an oxidant gas supplied to the cathode electrode of the fuel cell stack 20 flows, and an oxidant off gas flow path through which an oxidant off gas discharged from the fuel cell stack 20 flows. 34. The oxidant gas flow path 33 is provided with an air compressor 32 that takes in the oxidant gas from the atmosphere via the filter 31 and a shutoff valve A1 for shutting off the oxidant gas supply to the fuel cell stack 20. Yes. The oxidant off-gas flow path 34 is provided with a shut-off valve A2 for shutting off the oxidant off-gas discharge from the fuel cell stack 20, and a back pressure adjusting valve A3 for adjusting the oxidant gas supply pressure. .

  The fuel gas supply system 40 is discharged from the fuel gas supply source 41, the fuel gas flow path 43 through which the fuel gas supplied from the fuel gas supply source 41 to the anode electrode of the fuel cell stack 20 flows, and the fuel cell stack 20. A circulation passage 44 for returning the fuel off-gas to the fuel gas passage 43, a circulation pump 45 for pressure-feeding the fuel off-gas in the circulation passage 44 to the fuel gas passage 43, and a branch connection to the circulation passage 44. And an exhaust drainage channel 46.

  The fuel gas supply source 41 is composed of, for example, a high-pressure hydrogen tank or a hydrogen storage alloy, and stores high-pressure (for example, 35 MPa to 70 MPa) hydrogen gas. When the shut-off valve H1 is opened, the fuel gas flows out from the fuel gas supply source 41 into the fuel gas passage 43. The fuel gas is decompressed to, for example, about 200 kPa by the regulator H2 and injectors INJ1, INJ2, and INJ3, and supplied to the fuel cell stack 20. The fuel gas supply source 41 includes a reformer that generates a hydrogen-rich reformed gas from a hydrocarbon-based fuel, and a high-pressure gas tank that stores the reformed gas generated by the reformer in a high-pressure state. It may be configured.

  In the fuel gas flow path 43, a shutoff valve H1 for shutting off or permitting the supply of the fuel gas from the fuel gas supply source 41, a regulator H2 for adjusting the pressure of the fuel gas, and a fuel gas to the fuel cell stack 20 are provided. Three injectors INJ1, INJ2, and INJ3 for controlling the supply amount, a shutoff valve H3 for shutting off the fuel gas supply to the fuel cell stack 20, and pressure sensors 73 and 74 are provided.

  The regulator H2 is a device that regulates the upstream pressure (primary pressure) to a preset secondary pressure, and includes, for example, a mechanical pressure reducing valve that reduces the primary pressure. The mechanical pressure reducing valve has a housing 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. It has a configuration for the next pressure. By arranging the regulator H2 on the upstream side of the injectors INJ1, INJ2, and INJ3, the upstream pressure of the injectors INJ1, INJ2, and INJ3 can be effectively reduced. For this reason, the design freedom of the mechanical structures (valves, housings, flow paths, driving devices, etc.) of the injectors INJ1, INJ2, and INJ3 can be increased.

  Further, since the upstream pressure of the injectors INJ1, INJ2, and INJ3 can be reduced, the injectors INJ1, INJ2, and INJ3 are caused by the increase in the differential pressure between the upstream pressure and the downstream pressure of the injectors INJ1, INJ2, and INJ3. It is possible to prevent the valve body from becoming difficult to move. Therefore, it is possible to widen the adjustable pressure width of the downstream pressure of the injectors INJ1, INJ2, and INJ3, and it is possible to suppress a decrease in responsiveness of the injectors INJ1, INJ2, and INJ3.

  The fuel gas flow path 43 is divided into three flow paths 431, 432, and 433 that are partially parallel to each other, and the flow paths 431, 432, and 433 are electromagnetic valves that switch between a closed state and an open state. Injectors INJ1, INJ2, and INJ3 are arranged, respectively. Each of the injectors INJ1, INJ2, and INJ3 includes a valve seat having an injection hole for injecting fuel gas, a nozzle body that supplies and guides the fuel gas to the injection hole, and an axial direction (gas) with respect to the nozzle body. And a valve body that is accommodated and held so as to be movable in the flow direction) and opens and closes the injection hole.

  The valve bodies of the injectors INJ1, INJ2, and INJ3 are driven by solenoids L1, L2, and L3, which are electromagnetic driving devices, respectively. The opening and closing of each injection hole can be individually switched by the current supplied from the control device CTR to the solenoids L1, L2, and L3. For example, when a current is supplied to the solenoid L1 of the injector INJ1, the valve body is separated from the valve seat, the injection hole is opened, and the flow path 431 is opened. On the other hand, when the supply of current is stopped, the valve body comes into contact with the valve seat, the injection hole is closed, and the flow path 431 is closed.

  The control device CTR individually controls the opening / closing operation as described above in the injectors INJ1, INJ2, and INJ3. The flow rate of the fuel gas passing through the fuel gas flow path 43 is adjusted by controlling the injectors INJ1, INJ2, and INJ3 to be repeatedly opened and closed at a predetermined cycle. The flow rates of the fuel gas passing through the flow paths 431, 432, and 433 are adjusted by appropriately changing the open / close cycle of the injectors INJ1, INJ2, and INJ3.

  The control device CTR measures the pressure of the fuel gas on the upstream side of the injectors INJ1, INJ2, and INJ3 with the pressure sensor 73, and measures the pressure of the fuel gas on the downstream side with the pressure sensor 74. The control device CTR determines the opening / closing cycle of the injectors INJ1, INJ2, and INJ3 so that the flow rate of the fuel gas passing through the flow paths 431, 432, and 433 becomes a predetermined flow rate based on the pressure measured by these. .

  Further, the control device CTR does not always supply fuel gas through all three injectors, but performs control such that some of the injectors are closed according to the required load. For example, when the required load is small, the flow rate of the fuel gas supplied to the fuel cell stack 20 is adjusted by closing the two injectors and opening and closing the remaining one injector. On the other hand, when the required load is large, the flow rate of the fuel gas supplied to the fuel cell stack 20 is adjusted by opening and closing all three injectors. As described above, the flow rate of the fuel gas passing through the fuel gas flow path 43 can be adjusted in a wide range by appropriately changing the number of injectors operated to supply the fuel gas.

  The circulation passage 44 is connected to a shutoff valve H4 for shutting off the fuel off-gas discharge from the fuel cell stack 20 and an exhaust drainage passage 46 branched from the circulation passage 44. An exhaust / drain valve H5 is disposed in the exhaust / drain passage 46. The exhaust / drain valve H5 is operated according to a command from the control device CTR, and thereby discharges the fuel off-gas containing impurities in the circulation passage 44 and moisture to the outside. By opening the exhaust / drain valve H5, the concentration of impurities in the fuel off-gas in the circulation passage 44 is reduced, and the hydrogen concentration in the fuel off-gas circulating in the circulation system can be increased.

  The fuel off-gas discharged through the exhaust / drain valve H5 is mixed with the oxidant off-gas flowing through the oxidant off-gas passage 34 and diluted by a diluter (not shown). The circulation pump 45 circulates and supplies the fuel off gas in the circulation system to the fuel cell stack 20 by driving the motor.

  The control device CTR is a computer system including a CPU 61, a ROM, a RAM, and an input / output interface, and controls each part of the fuel cell system 10. For example, the control device CTR obtains the required power from the load based on an accelerator opening signal output from an accelerator sensor of the fuel cell vehicle. That is, the control device CTR has a function as required power detection means for detecting required power. The control device CTR determines the target power of the fuel cell stack 20 based on the required power, and sets the oxidant gas supply system 30 and the fuel gas supply system 40 so that the generated power of the fuel cell stack 20 matches the target power. Control.

  Next, control of the injectors INJ1, INJ2, and INJ3 by the control device CTR will be described in detail. The control device CTR includes a first control unit CTR1 for controlling the operation of the injector INJ1, a second control unit CTR2 for controlling the operation of the injector INJ2, and a third control unit for controlling the operation of the injector INJ3. CTR3.

  First, the configuration of the first control unit CTR1 that controls the operation of the injector INJ1 will be described with reference to FIG. FIG. 2 is a diagram illustrating a partial configuration of the control device CTR, and illustrates a specific configuration of the first control unit CTR1. As shown in FIG. 2, the first control unit CTR1 is a part that supplies current to the solenoid L1 of the injector INJ1 based on a control signal received from the CPU 61.

  The first control unit CTR1 includes a battery line BAT1 which is a current path connected to the battery, a first inrush circuit which is a current path connected from the battery line BAT1 to the switching element PF1, the solenoid L1, and the switching element IF1, and the battery. A first holding circuit which is a current path connected from the line BAT1 to the switching element PF1, the solenoid L1, and the switching element KF1. The battery is a power storage device that outputs a predetermined voltage, and is a supply source of current supplied to the solenoid L1.

  The switching element PF1 is an N-channel FET (field effect transistor), and is a switching element arranged to open and close a current path that leads from the battery line BAT1 to the solenoid L1. The control device CTR amplifies the control signal from the CPU 61 by the amplifier 62 and then inputs it to the gate terminal of the switching element PF1, thereby changing the gate-source voltage of the switching element PF1 and controlling its opening and closing. During operation of the fuel cell system 10, the switching element PF1 is always closed except during an emergency stop.

  The switching element IF1 and the switching element KF1 are also N-channel FETs (field effect transistors) similar to the switching element PF1. Each of them is connected in parallel between the solenoid L1 and the ground portion GND.

  The control device CTR amplifies the control signal from the CPU 61 by the amplifier 63 and then inputs it to the gate terminal of the switching element IF1, thereby changing the gate-source voltage of the switching element IF1 and controlling its opening and closing. Similarly, the control device CTR amplifies the control signal from the CPU 61 by the amplifier 64 and then inputs it to the gate terminal of the switching element KF1, thereby changing the gate-source voltage of the switching element KF1 and controlling its opening and closing. To do.

  A current measuring resistor IR is disposed between the switching element KF1 and the ground portion GND. Both ends of the current measuring resistor IR are connected to the amplifier 65, and a potential difference (potential drop amount) between both ends of the current measuring resistor IR is input to the amplifier 65. The amplifier 65 measures a potential difference at both ends of the current measurement resistor IR and inputs a signal obtained by amplifying the potential difference to the CPU 61. Since this potential difference is proportional to the current passing through the current measuring resistor IR, the current measuring resistor IR and the amplifier 65 are current measuring means for measuring the current flowing from the solenoid L1 to the switching element KF1. It functions as. That is, the magnitude of the current flowing through the current measurement resistor IR is input to the CPU 61 from the amplifier 65.

  When the injector INJ1 is in the closed state (the flow path 431 is in the closed state), both the switching element IF1 and the switching element KF1 are in the open state. That is, the first inrush circuit and the first holding circuit are both open, and no current flows through the solenoid L1.

  Subsequently, when the injector INJ1 is switched from the closed state to the open state, first, only the switching element IF1 is closed, and the first inrush circuit is closed, whereby current is supplied from the battery line BAT1 to the solenoid L1.

  At this time, the time change of the current I supplied to the solenoid L1 is shown in FIG. After the switching element IF1 is closed at time t0, the current I increases with time while being influenced by the inductance of the solenoid L1. When the magnitude of the current I exceeds I1, the valve body of the injector INJ1 is driven by electromagnetic force and moves to a position separated from the valve seat. Therefore, at the time t1, the injector INJ1 is opened, and the fuel gas is supplied to the fuel cell stack 20 through the flow path 431.

  Thereafter, in the period from time t1 to time t2, the injector INJ1 is maintained in the open state, but the current I supplied to the solenoid L1 during that period may be a current (I2) lower than I1. This is because, in order to move the valve body of the injector INJ1 from the position in contact with the valve seat to a position separated from the valve seat, a large electromagnetic force is required to resist static frictional force and inertial force. Thereafter, in order to hold the valve body of the injector INJ1 at a position separated from the valve seat, no force against static frictional force or inertial force is required (because the valve body does not move), and the necessary electromagnetic force Is small. Therefore, in this embodiment, the current supplied to the solenoid L1 after time t1 is reduced to I2, and the power required for the operation of the injector INJ1 is reduced.

  More specifically, the CPU 61 issues a control signal to the amplifier 63 so as to open the switching element IF1 at time t1. For this reason, as shown in FIG. 4, the current I supplied to the solenoid L1 starts to decrease from time t1.

  Here, the current flowing through the current measurement resistor IR, that is, the magnitude of the current flowing through the solenoid L1 is input from the amplifier 65 to the CPU 61. Based on the magnitude of the current, the CPU controls the operation of the switching element KF1 so that the magnitude of the current I supplied to the solenoid L1 substantially matches I2.

  When the current I decreases and falls below I2, the CPU 61 issues a control signal to the amplifier 64 so as to close the switching element KF1. Since the first holding circuit is closed, the current I begins to increase again. Thereafter, when the current I increases and exceeds I2, the CPU 61 issues a control signal to the amplifier 64 to open the switching element KF1. Since the first holding circuit is opened, the current I begins to decrease again. In this way, so-called chopper control is performed in which the switching operation of the switching element KF1 is repeated at a high speed, so that the current I supplied to the solenoid L1 during the period from time t1 to time t2 as shown in FIG. Is substantially equal to I2 and becomes a current that pulsates in the vicinity of I2. Although omitted in the present embodiment, it is desirable to remove such pulsation by providing a noise filter circuit including a capacitor or the like between the first control unit CTR1 and the solenoid L1.

  As described above, the first control unit CTR1 that controls the operation of the injector INJ1 is a circuit that supplies the current I to the injector INJ1 from the battery (first power supply unit) that is a supply source of the current I. And a first holding circuit (first circuit) having a switching element KF1 (first switch part) for switching between opening and closing of the circuit. The first control unit CTR1 has a function of setting the magnitude of the current I (first current) flowing through the injector INJ1 to I2 (first predetermined value) by performing chopper control that repeatedly opens and closes the switching element KF1 at high speed. Have.

  Next, the configuration of the second control unit CTR2 that controls the operation of the injector INJ2 will be described with reference to FIG. FIG. 3 is a diagram illustrating a partial configuration of the control device CTR, and illustrates a specific configuration of the second control unit CTR2. As shown in FIG. 3, the second control unit CTR2 is a part that supplies current to the solenoid L2 of the injector INJ2 based on a control signal received from the CPU 61. The third control unit CTR3 that controls the operation of the injector INJ3 is the same as the configuration of the second control unit CTR2 described below, and thus the description thereof is omitted.

  The second control unit CTR2 includes a battery line BAT2 which is a current path connected to the battery, a second inrush circuit which is a current path connected from the battery line BAT2 to the switching element PF2, the solenoid L2, and the switching element IF2, and the battery. The second holding circuit which is a current path connected from the line BAT2 to the switching element PF2, the solenoid L2, the voltage dividing resistor SR, and the switching element KF2. The battery is a power storage device that outputs a predetermined voltage, and is a source of current supplied to the solenoid L2.

  The switching element PF2 is an N-channel FET (field effect transistor), and is a switching element arranged to open and close a current path that leads from the battery line BAT2 to the solenoid L2. The control device CTR amplifies the control signal from the CPU 61 with the amplifier 66 and then inputs it to the gate terminal of the switching element PF2, thereby changing the gate-source voltage of the switching element PF2 and controlling its opening and closing. During operation of the fuel cell system 10, the switching element PF2 is always closed except during an emergency stop.

  The switching element IF2 and the switching element KF2 are also N-channel FETs (field effect transistors) similar to the switching element PF2. Each of them is connected in parallel between the solenoid L2 and the ground portion GND.

  The control device CTR amplifies the control signal from the CPU 61 by the amplifier 67 and then inputs it to the gate terminal of the switching element IF2, thereby changing the gate-source voltage of the switching element IF2 and controlling its opening and closing. Similarly, the control device CTR amplifies the control signal from the CPU 61 by the amplifier 68 and then inputs it to the gate terminal of the switching element KF2, thereby changing the gate-source voltage of the switching element KF2 and controlling its opening and closing. To do.

  In the second holding circuit, a voltage dividing resistor SR is disposed between the solenoid L2 and the switching element KF2. The voltage dividing resistor SR is an electric resistor having a constant resistance value, and is connected in series with the solenoid L2 in the second holding circuit.

  When the injector INJ2 is in the closed state (the flow path 432 is in the closed state), both the switching element IF2 and the switching element KF2 are in the open state. That is, both the second inrush circuit and the second holding circuit are open, and no current flows through the solenoid L2.

  Subsequently, when switching the injector INJ2 from the closed state to the open state, first, only the switching element IF2 is closed, and the second inrush circuit is closed, whereby current is supplied from the battery line BAT2 to the solenoid L2.

  At this time, the time change of the current I supplied to the solenoid L2 is shown in FIG. After the switching element IF2 is closed at time t0, the current I increases with time while being influenced by the inductance of the solenoid L2. When the magnitude of the current I exceeds I1, the valve body of the injector INJ2 is driven by electromagnetic force and moves to a position separated from the valve seat. Therefore, at the time t1, the injector INJ2 is opened, and the fuel gas is supplied to the fuel cell stack 20 through the flow path 432.

  Thereafter, in the period from time t1 to time t2, the injector INJ2 is maintained in the open state, but the current I supplied to the solenoid L2 during that period may be a current (I2) lower than I1. This is because, in order to move the valve body of the injector INJ2 from the position in contact with the valve seat to a position away from the valve seat, a large electromagnetic force is required to resist the static frictional force and inertial force. Thereafter, in order to hold the valve body of the injector INJ2 at a position separated from the valve seat, no force against static frictional force or inertial force is required (because the valve body does not move), and the necessary electromagnetic force Is small. Therefore, in this embodiment, the current supplied to the solenoid L2 after time t1 is reduced to I2, and the power required for the operation of the injector INJ2 is reduced.

  More specifically, the CPU 61 issues a control signal for opening the switching element IF2 to the amplifier 67 at time t1. At the same time, a control signal for closing the switching element KF2 is issued to the amplifier 68. That is, the second inrush circuit is opened and the second holding circuit is closed. Here, in the second holding circuit, a voltage dividing resistor SR is arranged in series with the solenoid L2. For this reason, the electrical resistance along the second holding circuit is larger than the electrical resistance along the second inrush circuit. As a result, the current I flowing from the battery line BAT2 through the solenoid L2 to the ground portion GND starts to decrease from time t1 and decreases to I2. In other words, the resistance value of the voltage dividing resistor SR is determined in advance so that the magnitude of the current I that constantly flows through the second holding circuit is I2.

  As described above, the second control unit CTR2 that controls the operation of the injector INJ2 is a circuit for supplying the current I from the battery (second power supply unit) to the injector INJ2 from the battery. A second holding circuit (second circuit) having a switching element KF2 (second switch part) for switching between opening and closing of the circuit and a voltage dividing resistor SR connected in series with the injector INJ2 in the circuit. Yes. The second controller CTR2 has a function of setting the magnitude of the current I (second current) flowing through the injector INJ2 to I2 (second predetermined value) by closing the switching element KF2 and closing the second holding circuit. have.

  That is, in the fuel cell system 10 according to the present embodiment, the current supplied to the injector for maintaining the flow path in the open state is set to a predetermined value by repeatedly switching the switching element KF1 at high speed. A first control unit CTR1 (chopper control configuration) is provided. Further, the current supplied to the injector for maintaining the flow path in the open state is set to a predetermined value by closing a circuit connecting the injector and the voltage dividing resistor SR in series (voltage dividing resistor configuration). ) Second control unit CTR2 and third control unit CTR3.

  For this reason, the control device CTR is downsized and the number of parts is further reduced as compared with the case where all the control units have a chopper control configuration. Further, as compared with a case where all the control units have a voltage dividing resistor configuration, generation of useless power consumption caused by current passing through the voltage dividing resistor SR is suppressed.

  As described above, the control device CTR does not always supply fuel gas through all three injectors, but performs control such that some of the injectors are closed according to the required load.

  Specifically, when the required load is smaller than the first predetermined value, the injectors INJ2 and INJ3 are always closed, and the fuel supplied to the fuel cell stack 20 only from the flow path 431 in which the injector INJ1 is disposed. Supply gas. That is, the fuel gas is supplied only from the injector INJ1 controlled by the first control unit CTR1.

  When the required load is equal to or greater than the first predetermined value and smaller than the second predetermined value, the injector INJ3 is always kept closed, and the flow path 431 in which the injector INJ1 is disposed and the injector INJ2 are disposed. The fuel gas supplied to the fuel cell stack 20 is supplied from the flow path 432. In addition, when the required load is equal to or greater than the second predetermined value, the fuel cell includes the flow path 431 in which the injector INJ1 is disposed, the flow path 432 in which the injector INJ2 is disposed, and the flow path 433 in which the injector INJ3 is disposed. The fuel gas supplied to the stack 20 is supplied.

  By performing such control, the frequency at which the flow path 432 and the flow path 433 are opened, that is, the frequency at which the holding current is supplied to the injector INJ2 and the injector INJ3 to maintain the open state is reduced. Energy consumed by the current I passing through the resistor SR is reduced. As a result, the fuel utilization efficiency in the fuel cell system 10 is improved.

  In this embodiment, the injectors (injectors INJ2 and INJ3) controlled by the control units (second control unit CTR2 and third control unit CTR3) having a voltage dividing resistor configuration are connected in parallel to each other. Although the example provided with two was demonstrated, as embodiment of this invention, it is not restricted to such an aspect, You may provide three or more such injectors in parallel.

  Further, in the present embodiment, an example in which only one injector (injector INJ1) controlled by the control unit (first control unit CTR1) having a chopper control configuration is provided has been described. It is good also as a structure provided with two or more control parts in parallel. When performing control to appropriately change the number of injectors through which fuel gas passes based on the required power, the larger the number of injectors that are controlled individually, the wider the amount of fuel gas supplied to the fuel cell. The range can be adjusted.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. For example, the elements included in each of the specific examples described above and their arrangement, materials, conditions, shapes, sizes, and the like are not limited to those illustrated, but can be changed as appropriate. Moreover, each element with which each embodiment mentioned above is provided can be combined as long as technically possible, and the combination of these is also included in the scope of the present invention as long as it includes the features of the present invention.

DESCRIPTION OF SYMBOLS 10: Fuel cell system 20: Fuel cell stack 30: Oxidant gas supply system 31: Filter 32: Air compressor 33: Oxidant gas flow path 34: Oxidant off gas flow path 40: Fuel gas supply system 41: Fuel gas supply source 43: Fuel gas flow path 431, 432, 433: Flow path 44: Circulation flow path 45: Circulation pump 46: Exhaust drainage flow path 62, 63, 64, 65, 66, 67, 68: Amplifier 73, 74: Pressure sensor A1, A2: shut-off valve A3: back pressure regulating valve BAT1, BAT2: battery line CTR: control device CTR1: first control unit CTR2: second control unit CTR3: third control unit GND: grounding unit H1, H3, H4: Shut-off valve H2: Regulator H5: Exhaust drain valve IF1, IF2, KF1, KF2, PF1, PF2: Switching elements INJ1, INJ2 , INJ3: Injector IR: Resistance for current measurement L1, L2: Solenoid SR: Voltage dividing resistance

Claims (3)

A fuel cell that receives supply of the fuel gas and the oxidant gas and generates power by an electrochemical reaction of the fuel gas and the oxidant gas;
A first fuel flow path that is a flow path for supplying the fuel gas to the fuel cell;
A flow path for supplying the fuel gas to the fuel cell, wherein the second fuel flow path is arranged in parallel with the first fuel flow path;
A flow path for supplying the fuel gas to the fuel cell, wherein the third fuel flow path is arranged in parallel with the second fuel flow path;
A first injector that is driven by receiving a current and switches between an open state and a closed state of the first fuel flow path;
A second injector that is driven by the supply of current and switches between an open state and a closed state of the second fuel flow path;
A third injector that is driven by receiving a current supply and switches between an open state and a closed state of the third fuel flow path;
A first controller that maintains the first fuel flow path in an open state by setting the magnitude of the first current supplied to the first injector to a first predetermined value;
A second control unit that maintains the second fuel flow path in an open state by setting the second current supplied to the second injector to a second predetermined value;
A third control unit that maintains the second fuel flow path in an open state by setting the magnitude of the third current supplied to the third injector to a third predetermined value;
In a fuel cell system comprising:
The first controller is
A first power supply unit that is a supply source of the first current;
A circuit for supplying the first current from the first power supply unit to the first injector, the first circuit having a first switch unit for switching opening and closing of the circuit,
While performing chopper control that repeats the opening and closing operation of the first switch part at high speed, the magnitude of the first current is set to the first predetermined value,
The second controller is
A second power source that is a source of the second current;
A circuit for supplying the second current from the second power supply unit to the second injector, and a second switch unit that switches between opening and closing of the circuit and an amount connected in series with the second injector in the circuit A second circuit having a piezoresistor,
By the closed said second circuit closing said second switching unit state, and are the size of the second current which said second predetermined value,
The third control unit
A third power source that is a source of the third current;
A circuit for supplying the third current from the third power supply unit to the third injector, the third switch unit for switching opening and closing of the circuit, and an amount connected in series with the third injector in the circuit A third circuit having a piezoresistor,
By closing the third switch part and closing the third circuit, the magnitude of the third current is set to the third predetermined value,
Controlling the magnitude of the power generated by the fuel cell based on the required power from the load,
When the required power is smaller than a fourth predetermined value, the second injector and the third injector are always closed, the fuel gas is supplied to the fuel cell only from the first fuel flow path,
When the required power is not less than the fourth predetermined value and smaller than the fifth predetermined value, the third injector is always kept closed, and the fuel gas is supplied to the fuel cell by the first fuel. From the flow path and the second fuel flow path,
When the required power is greater than or equal to the fifth predetermined value, the fuel gas is supplied to the fuel cell from the first fuel channel, the second fuel channel, and the third fuel channel. A fuel cell system. A plurality of the first injectors are provided in a state of being connected in parallel to each other in the first fuel flow path, and a plurality of the first control units corresponding to the respective first injectors are provided. The fuel cell system according to claim 1 , wherein the fuel cell system is characterized. A plurality of the second injectors are provided in a state of being connected in parallel with each other in the second fuel flow path, and a plurality of the second control units corresponding to the respective second injectors are provided. wherein, the fuel cell system according to claim 1 or claim 2.

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