JP2008271655A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid fuel cell system enabling a user to check operations of the fuel cell system and check operations of a road-going function system in pulling away a car. <P>SOLUTION: An activation control section 801 controls the activation (start) of a road-going system such as a motor for travelling a car, and the section 801 sets a flag F<SB>A</SB>for permitting the activation (start) of the drive system when AND is established between a signal Se from a power supply control section 802 and a signal Sr from a road-going function control section 803. If the flag F<SB>A</SB>is set, a drive system control section 804 activates the road-going system and calculates the control amount of the road-going system (e.g. motor 94 for driving a car) on the basis of an operation quantity such as acceleration or braking by a driver, and controls the road-going system using this control quantity. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell system, and more particularly to a hybrid fuel cell system mounted on a vehicle (moving body).

  In an engine-type hybrid vehicle that runs on a drive motor using an engine starter generator and a battery as a power source, the hydraulic pump for power steering is also driven by the engine (equipped with so-called hydraulic power steering) If the engine is low or the engine is stopped, as long as the battery can supply the necessary torque to the vehicle motor, the vehicle It is possible to run.

  However, when traveling in such a state, the output of the hydraulic pump for power steering is low or stopped because the engine output is low or the engine is stopped. Since the power of the car does not reach the rating, the handle operation becomes heavy.

  Therefore, for example, Japanese Patent Application Laid-Open No. 8-98318 proposes a “control method for a hybrid electric vehicle” that gives a travel permission after confirming that the engine exhibits a predetermined rotational speed (Patent Document 1). .

Further, in a hybrid vehicle equipped with a fuel cell, for example, as described in Japanese Patent Application Laid-Open No. 9-231991, the period from the start to the time when the fuel cell can generate power is from the secondary battery. Electric power was supplied to perform warm-up operation, and after the fuel cell warm-up was completed, the power of the fuel cell was supplied to the vehicle driving motor (Patent Document 2, Abstract).
JP-A-8-98318 (paragraph 0020, etc.) Japanese Patent Laid-Open No. 9-231991 (abstract)

  However, when a power steering function is provided in a fuel cell type hybrid vehicle, the above-described conventional technology is a control technology for an engine type hybrid electric vehicle, and thus cannot be applied to a fuel cell type hybrid vehicle as it is. was there.

  For example, in an engine-type hybrid vehicle, the hydraulic pump for power steering is operated by the engine. Therefore, if the power steering function is not activated after the engine output has increased, there will be a difference in the weight of the steering wheel operation. However, in a fuel cell type hybrid vehicle, a hydraulic pump for power steering is driven by electric power supplied from one or both of the fuel cell and the secondary battery.

  Here, in the fuel cell type hybrid vehicle, as in Patent Document 2, if the power steering function is enabled after the warm-up operation of the fuel cell is completed, a certain time is required for the warm-up operation at the start. Therefore, there is an inconvenience that it takes too much time until the power steering function can be used.

  On the other hand, during the warm-up operation of the fuel cell, power can be supplied from the secondary battery to the auxiliary machinery, but if the power steering function is enabled when the secondary battery can be supplied, Since the power for power steering does not reach the rated power from the battery power supply until the rotational speed of the hydraulic pump for power steering becomes constant, the steering operation immediately after the start of power supply to the secondary battery becomes heavy. There was also an inconvenience.

  Therefore, in order to solve the above problems, the present invention can start traveling in a relatively short time in a hybrid vehicle equipped with a fuel cell system, and can prevent the steering operation from becoming heavy immediately after the start of traveling. An object of the present invention is to provide a hybrid fuel cell system mounted on a moving body.

  In order to solve the above problems, a fuel cell system of the present invention is a hybrid fuel cell system that is mounted on a mobile body and has a fuel cell and a secondary battery as a power source of the mobile body, the fuel cell system And a power supply control unit that controls the operation of the secondary battery, a travel function control unit that controls a predetermined travel function of the moving body, and a start control unit that controls start-up at start-up. The control unit is configured to control to permit the traveling of the moving body when both the completion of the activation of the secondary battery and the completion of the activation of the traveling function are satisfied. To do.

  By configuring in this way, even before the fuel cell is started, the vehicle is allowed to start after confirming the start of the travel function and at the same time confirming the start of the travel function. It is possible to prevent inconvenience that the function is caused to malfunction, and to contribute to the improvement of the stability of the moving body.

  Further, in the fuel cell system, the traveling function can be a power steering function, and the traveling is permitted after confirming the activation of the power steering function at the same time as confirming the activation of the secondary battery. An inconvenient state in which the steering wheel operation becomes heavy immediately after the start can be prevented, and the operability of the moving body can be improved.

  Further, since the power steering function may be either an electric type or an electrohydraulic type, it becomes possible to save fuel consumption compared to a hydraulic power steering function using a conventional engine as a power source. It can also be installed in large vehicles.

  Furthermore, since the power steering function is configured to be operable only by supplying power from the secondary battery, activation can be started after the secondary battery can supply power.

  According to the present invention, the hybrid battery is controlled so as to permit the traveling of the moving body when both the completion of the activation of the secondary battery and the completion of the activation of the traveling function are satisfied. In a moving body equipped with a fuel cell system, it is possible to start traveling in a relatively short time and to prevent the steering operation from becoming heavy immediately after the start of traveling.

Next, preferred embodiments for carrying out the present invention will be described with reference to the drawings.
In the embodiment of the present invention, the present invention is applied to an electric vehicle equipped with a fuel cell. The following embodiments are merely examples of the application form of the present invention, and do not limit the present invention.

  In this embodiment, after confirming that the secondary battery is operable and that the preparation of the traveling system such as power steering is completed, the drive system (here, at least the vehicle traveling motor 94 is applicable). )) Is allowed to start.

  FIG. 1 is a system configuration diagram of a fuel cell system to which the present invention is applied.

  In FIG. 1, a fuel cell system 10 supplies, as main components, a fuel gas supply system 4 for supplying fuel gas (hydrogen gas) to the fuel cell 20 and an oxidizing gas (air) to the fuel cell 20. An oxidizing gas supply system 7 for cooling, a coolant supply system 3 for cooling the fuel cell 20, a power system 9 for charging / discharging generated power from the fuel cell 20, and a power steering control unit 110 for controlling the power steering function And a power steering drive motor 111 that is a drive motor for power steering.

  The fuel cell 20 is a membrane / electrode junction in which an anode electrode 22 and a cathode electrode 23 are formed on both surfaces of a polymer electrolyte membrane 21 made of a proton-conducting ion exchange membrane made of fluorine-based resin or the like by screen printing or the like. A body 24 is provided. Both surfaces of the membrane / electrode assembly 24 are sandwiched by separators (not shown) having flow paths of fuel gas, oxidizing gas, and cooling water, and grooves are respectively formed between the separator and the anode electrode 22 and the cathode electrode 23. An anode gas channel 25 and a cathode gas channel 26 are formed. The anode electrode 22 is configured by providing a fuel electrode catalyst layer on a porous support layer, and the cathode electrode 23 is configured by providing an air electrode catalyst layer on the porous support layer. The catalyst layers of these electrodes are configured by adhering platinum particles, for example.

  The anode electrode 22 undergoes an oxidation reaction of the following formula (1), and the cathode electrode 23 undergoes a reduction reaction of the following formula (2). In the fuel cell 20 as a whole, an electromotive reaction of the following formula (3) occurs.

H ₂ → 2H ⁺ + 2e ⁻ (1)
(1/2) O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (2)
H ² + (1/2) O 2 → H ₂ O (3)

  In FIG. 1, for convenience of explanation, the structure of a unit cell composed of a membrane / electrode assembly 24, an anode gas channel 25, and a cathode gas channel 26 is schematically shown. And a stack structure in which a plurality of unit cells (cell groups) are connected in series.

  The coolant supply system 3 of the fuel cell system 10 includes a cooling path 31 for circulating the coolant, a temperature sensor 32 for detecting the temperature of the coolant drained from the fuel cell 20, and a radiator for radiating the heat of the coolant to the outside. (Heat exchanger) 33, a valve 34 that adjusts the amount of coolant flowing into the radiator 33, a coolant pump 35 that pressurizes and circulates coolant, and a temperature of coolant supplied to the fuel cell 20 is detected. A temperature sensor 36 or the like is provided.

  The fuel gas supply system 4 of the fuel cell system 10 includes a fuel gas flow path 40 for supplying fuel gas (anode gas), for example, hydrogen gas, from the fuel gas supply device 42 to the anode gas channel 25, and an anode gas. A circulation passage (circulation passage) 51 for circulating the fuel off-gas exhausted from the channel 25 to the fuel gas passage 40 is piped, and a fuel gas circulation system is constituted by these gas passages.

  In the fuel gas passage 40, a shutoff valve (original valve) 43 that controls the outflow of fuel gas from the fuel gas supply device 42, a pressure sensor 44 that detects the pressure of the fuel gas, and a fuel gas pressure in the circulation path 51 are adjusted. A regulating valve 45 and a shutoff valve 46 for controlling the supply of fuel gas to the fuel cell 20 are installed.

  The fuel gas supply device 42 includes, for example, a high-pressure hydrogen tank, a hydrogen storage alloy, a reformer, and the like. The circulation channel 51 includes a shut-off valve 52 that controls the supply of fuel off-gas from the fuel cell 20 to the circulation channel 51, a gas-liquid separator 53 and a discharge valve 54 that removes water contained in the fuel off-gas, and an anode gas channel 25. The hydrogen pump (circulation pump) 55 that compresses the fuel off-gas that has undergone pressure loss and raises the pressure to an appropriate gas pressure when returning to the fuel gas passage 40 when passing through the fuel gas, and the fuel gas in the fuel gas passage 40 Is provided with a backflow prevention valve 56 for preventing the backflow of the airflow toward the circulation channel 51 side. By driving the hydrogen pump 55 with a motor, the fuel off-gas generated by driving the hydrogen pump 55 merges with the fuel gas supplied from the fuel gas supply device 42 in the fuel gas flow path 40 and then supplied to the fuel cell 20. Reused. The hydrogen pump 55 is provided with a rotation speed sensor 57 that detects the rotation speed of the hydrogen pump 55.

  Further, an exhaust passage 61 for branching the fuel off-gas exhausted from the fuel cell 20 to the outside of the vehicle via a diluter (for example, a hydrogen concentration reducing device) 62 is branched and connected to the circulation passage 51. Yes. A purge valve 63 is installed in the exhaust passage 61, and is configured to perform exhaust control of the fuel off gas. By opening and closing the purge valve 63, it is possible to repeatedly circulate in the fuel cell 20, discharge the fuel off-gas having increased impurity concentration to the outside, and introduce new fuel gas to prevent the cell voltage from decreasing. . It is also possible to remove the water accumulated in the gas flow path by causing a pulsation in the internal pressure of the circulation flow path 51.

  On the other hand, the oxidizing gas supply system 7 of the fuel cell system 10 exhausts an oxidizing gas passage 71 for supplying an oxidizing gas (cathode gas) to the cathode gas channel 26 and a cathode off-gas exhausted from the cathode gas channel 26. A cathode off-gas flow path 72 is provided for this purpose. An air cleaner 74 that takes in air from the atmosphere and an air compressor 75 that compresses the taken air and supplies the compressed air as an oxidant gas to the cathode gas channel 26 are set in the oxidizing gas channel 71. The air compressor 75 is provided with a rotation speed sensor 73 that detects the rotation speed of the air compressor 75. A humidifier 76 for exchanging humidity is provided between the oxidizing gas channel 71 and the cathode offgas channel 72. The cathode offgas passage 72 is provided with a pressure regulating valve 77 that adjusts the exhaust pressure of the cathode offgas passage 72, a gas-liquid separator 64 that removes moisture in the cathode offgas, and a muffler 65 that absorbs the exhaust sound of the cathode offgas. ing. The cathode off-gas discharged from the gas-liquid separator 64 is diverted, and one of the cathode off-gas flows into the diluter 62 and is mixed and diluted with the fuel off-gas that stays in the diluter 62. Is mixed with the gas diluted by the diluter 62 and discharged outside the vehicle.

  Further, the power system 9 of the fuel cell system 10 has a DC-DC converter 90 in which the output terminal of the battery 91 is connected to the primary side and the output terminal of the fuel cell 20 is connected to the secondary side, and a surplus as a secondary battery. A battery 91 that stores electric power, a battery computer 92 that monitors the charging state of the battery 91, an inverter 93 that supplies AC power to a load or driving vehicle 94 of the fuel cell 20, and various high voltages of the fuel cell system 10 An inverter 95 that supplies AC power to the auxiliary machine 96, a voltage sensor 97 that measures the output voltage of the fuel cell 20, and a current sensor 98 that measures the output current are connected.

  The DC-DC converter 90 converts the surplus power of the fuel cell 20 or the regenerative power generated by the braking operation to the vehicle travel motor 94 into a voltage and supplies it to the battery 91 for charging. Further, in order to compensate for the shortage of the generated power of the fuel cell 20 with respect to the required power of the vehicle travel motor 94, the DC-DC converter 90 converts the discharged power from the battery 91 to a secondary side after voltage conversion. .

  Inverters 93 and 95 convert a direct current into a three-phase alternating current and output the three-phase alternating current to vehicle running motor 94 and high voltage auxiliary machine 96, respectively. The vehicle travel motor 94 is provided with a rotational speed sensor 99 that detects the rotational speed of the motor 94. The wheel 94 is mechanically coupled to the motor 94 via a differential, and the rotational force of the motor 94 can be converted into the driving force of the vehicle.

  The voltage sensor 97 and the current sensor 98 are for measuring the AC impedance based on the phase and amplitude of the current with respect to the voltage of the AC signal superimposed on the power system 9. The AC impedance corresponds to the water content of the fuel cell 20. The water content measured by this AC impedance measurement corresponds to the average water content of the entire unit cells stacked on the fuel cell 20.

  Further, the fuel cell system 10 is provided with a control unit 80 for controlling power generation of the fuel cell 12, operation of the power steering control unit 110, and activation of the drive system described above. The control unit 80 is configured by a general-purpose computer including a CPU (Central Processing Unit), RAM, ROM, interface circuit, and the like, for example, and includes temperature sensors 32 and 36, a pressure sensor 44, and rotation speed sensors 57, 73, and 99. Sensor signals, voltage sensors 97, current sensors 98, and ignition switches 82 are taken in, and the motors are driven in accordance with the battery operating state, for example, the electric power load, so that the hydrogen pump 55 and the air compressor 75 The number of rotations is adjusted, and further, opening / closing control of various valves (valves) or adjustment of the valve opening is performed.

  The control unit 80 instructs the moisture content measurement unit including the voltage sensor 97 and the current sensor 98 to measure the moisture content of the entire fuel cell. When the moisture content of the entire fuel cell is inappropriate, the control unit 80 instructs the scavenging drive unit. Command the scavenging drive. Further, the control unit 80 measures the open circuit voltage for a specific unit cell in which the water content is likely to be relatively large among the unit cells with respect to the voltage measurement unit 101 even if the water content of the entire fuel cell is appropriate. And based on the rate of decrease in the open circuit voltage measured by the voltage measurement unit 101, the fuel cell 20 is configured to operate as a determination unit that determines whether or not the water content is appropriate.

  In particular, as a characteristic control operation of the present invention, the control unit 80 is able to operate the battery 91 and the preparation of a traveling system such as a power steering system including the power steering drive motor 111 is completed. After confirming that it is possible, the above-described drive system is allowed to start.

  The power steering control unit 110 performs various controls necessary for operating the power steering drive motor 111 that drives the power steering of the traveling system and the power steering function. The power steering drive motor 111 is a motor that drives an electric or electrohydraulic power steering.

  The power steering control unit 110 and the power steering drive motor 111 can realize either a power steering function of an electric type or an electric hydraulic type. The power source of the power steering control unit 110 and the driving power source of the power steering drive motor 111 may be either the fuel cell 20 or the battery 91, or both, but they are connected to their own power sources (including fuel cells in the category). May be.

FIG. 2 is a functional block diagram of the control unit 80 of the fuel cell system 10 to which the present invention is applied.
The control unit 80 shown in FIG. 2 has, as functional blocks, a start control unit 801 that controls the start (start) of the drive system described above, and a power source that controls the power system 9 of the fuel cell system such as the fuel cell 20 and the battery 91. A control unit 802, a travel function control unit 803 that controls the power steering function, and a drive system control unit 804 that controls the operation of the above-described drive system after startup.

  The activation control unit 801 receives a signal Se indicating that the power supply from the battery 91 can be supplied from the power supply control unit 802, and also receives a signal Sr indicating that the preparation of the power steering function is completed from the traveling function control unit 803. When received, it functions to allow activation of the drive train.

That is, the activation control unit 801 controls the activation (starting) of the traveling system such as the vehicle traveling motor 94, but the logical product of the signal Se from the power supply control unit 802 and the signal Sr from the traveling function control unit 803. when (aND) is satisfied, a flag F _a is allowed to start the above-mentioned drive system (start). When this flag F _A is set, the drive system control unit 804 activates the above-described travel system and controls the travel system control amount (for example, a vehicle travel motor) based on the driver's accelerator and brake operation amounts. 94 torque) is calculated, and the traveling system is controlled by this control amount.

  The power supply control unit 802 controls the general operation of the power system 9. For example, the start / stop / power generation amount of the fuel cell 20 is controlled, and charging / discharging of the battery 91 is controlled via the battery computer 92. Further, through this control, the state of the battery 91 is grasped, and when the electromotive force suitable for traveling can be output from the battery 91, the signal Se is sent to the activation control unit 801. Furthermore, the power supply control unit 802 includes the above-described systems (for example, the coolant supply system 3, the fuel gas supply system 4, and the oxidizing gas supply system 7) necessary for the operation of the fuel cell 20, and the above-described channels (for example, The fuel gas passage 40, the circulation passage 51, and the exhaust passage 61) are controlled. Further, through this control, it is detected that the activation of the fuel cell 20 has been completed, and a signal Se is sent to the activation control unit 801 when an electromotive force suitable for traveling is obtained in the fuel cell 20.

  The travel function control unit 803 controls a travel function system such as a power steering, a direction indicator, and a wiper. Further, through this control, the state of the traveling function system is grasped, and a signal Sr is sent to the activation control unit 801 when the state of the traveling function system suitable for traveling is obtained.

Driving system control unit 804, when are flagged F _A described above, while starting the aforementioned traveling system, control of the travel system based on the operation amount of the driver or the like of the accelerator and the brake (e.g., a vehicle traveling The torque of the motor 94) is calculated, and the traveling system is controlled by this control amount.

  The battery computer 92 is provided at the output terminal of the battery 91 and can communicate with the control unit 80. The battery computer 92 monitors the state of charge of the battery 91, maintains the battery within an appropriate charge range that does not lead to overcharge or overdischarge, and controls the control unit if the battery becomes overcharged or overdischarged. 80 is configured to be notified.

  As a result, when the preparation of the power steering function is not completed, the start of the vehicle travel motor 94 is not permitted, and when the preparation of the power steering function is completed and the steering operation becomes light as usual, the vehicle finally starts traveling. Therefore, it is possible to avoid the inconvenient state in which the vehicle travels despite the fact that the steering wheel operation is heavy and difficult as in the prior art, and the operability of the vehicle can be improved. .

  FIG. 3 is a flowchart showing the operation at the time of engine start of the control unit 80 of the fuel cell system to which the present invention is applied. Hereinafter, the operation at the time of engine start performed by the control unit 80 will be described with reference to FIGS.

  First, the activation control unit 801 waits until the signal Se is sent from the fuel control unit 802, and when the signal Se is sent from the power supply control unit 802, the process proceeds to step S2 (step S1).

  In step S2, the activation control unit 801 verifies whether or not the signal Sr is transmitted from the traveling function control unit 803. If the signal Sr is transmitted from the traveling function control unit 803, the process proceeds to step S3. Is not sent from the travel function control unit 803, the process returns to step S1.

  If both of the steps S1 and S2 result in YES, it is determined that the power can be supplied from the battery 91 and the power steering function can be operated.

Therefore, in step S3, the activation control unit 801 sets the flag F _A , and then in step S4, the drive system control unit 804 receives the fact that the flag F _A is set, and controls the drive system control amount (here Then, the torque St) of the vehicle travel motor 94 is calculated.

In step S5, the drive system control unit 804 uses the control amount (that is, the torque St of the vehicle travel motor 94) and the signal S _A corresponding to the flag F _A to drive the vehicle travel motor 94 of the drive system. To send.

  Next, in step S6, the activation control unit 801 verifies whether or not the drive system has been activated. If the drive system has not been activated, the process returns to step S3. If the drive system has been activated, the process proceeds to step S7. .

In step S7, the driving system control unit 804 receives that the flag F _A is erected, the control amount of the driving system (in this case the torque St of the vehicle traveling motor 94) is calculated.

  Next, in step S <b> 8, the drive system control unit 804 sends this control amount (that is, the torque St of the vehicle travel motor 94) to the drive system vehicle travel motor 94.

In step S9, the drive system control unit 804 verifies whether or not the drive system is stopped. If the drive system is not stopped, the process returns to step S7. If the drive system is stopped, the process proceeds to step S10. .
In step S10, the driving system control unit 804, down the flag F _A, the flow returns to step S1.
With the above operation, only when the power supply from the battery 91 is possible and the power steering function is effective, the vehicle driving motor 94 is allowed to generate torque, and thus driving is permitted. Therefore, the power steering function can be effectively functioned immediately after the vehicle starts. Therefore, it is possible to prevent the handle operation from becoming heavy.

(Other embodiments)
The present invention can be applied with various modifications other than the above embodiment.
For example, although the power steering function has been described as an example of the traveling function in the above embodiment, the present invention can be applied to other traveling functions other than the power steering function that take time to start.

  In addition, the present invention is highly effective when applied to a hybrid fuel cell system as in the present embodiment, but can also be applied to other general fuel cell systems.

  In the present embodiment, the electric power steering function is exemplified as the power steering function. However, the present invention is also applicable to a vehicle in which the hydraulic power steering function is used.

  Furthermore, the present invention can be applied not only to vehicles but also to any mobile body that is mounted on a hybrid fuel cell system and moves on land, underground, sea, sea, air, and outer space. .

1 is a system configuration diagram of a fuel cell system to which the present invention is applied. It is a functional block diagram of the control part 80 of the fuel cell system 10 with which this invention is applied. It is a flowchart figure which shows the operation | movement at the time of engine starting of the control part 80 of the fuel cell system with which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel cell system, 20 Fuel cell, 40 Fuel gas flow path, 55 Hydrogen pump, 71 Oxidation gas flow path, 80 Control part, 91 Battery,
92 battery computer, 110 power steering control unit,
111 Power Steer Drive Motor, 801 Start Control Unit, 802 Power Supply Control Unit 803 Travel Function Control Unit, S _A , Se, Sr, St Signal, F _A Flag

Claims (4)

A hybrid fuel cell system mounted on a mobile body and having a fuel cell and a secondary battery as a power source for the mobile body,
A power supply control unit for controlling operations of the fuel cell and the secondary battery;
A traveling function control unit for controlling a predetermined traveling function of the mobile body;
An activation control unit that controls activation at the time of starting,
The activation control unit performs control so as to permit the traveling of the moving body when both the completion of the activation of the secondary battery and the completion of the activation of the traveling function are satisfied. A hybrid fuel cell system. The hybrid fuel cell system according to claim 1, wherein the traveling function is a power steering function. The hybrid fuel cell system according to claim 2, wherein the power steering function is an electric type or an electrohydraulic type. The hybrid fuel cell system according to claim 2 or 3, wherein the power steering function is configured to be operable only by power supply from the secondary battery.

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