Abstract: An object of the present invention is to reduce the period of time required to stop a fuel cell system and to suppress freezing of a fuel cell. The fuel cell system includes a controller that controls operations of a fuel cell, and the controller operates the fuel cell in a dry condition according to a state quantity (e.g., impedance) of the fuel cell in operation. The controller can operate the fuel cell in a dry condition before a system stop command is issued. In addition, the controller can switch an operation of the fuel cell from a dry condition to a wet condition when a required output of the fuel cell or a vehicle speed of a vehicle equals or exceeds a predetermined value.

Abstract: Provided is a fuel cell system which can accurately detect the water state of a fuel cell to appropriately control the water content of the fuel cell. Based on an FC outlet temperature detected by a temperature sensor, an FC outlet temperature change speed detection unit detects an FC outlet temperature change speed for a unit time. If the FC outlet temperature change speed detection unit judges that the detected FC outlet temperature change speed is lower than a change speed reference value stored in a memory, an impedance measurement instruction is transmitted to an impedance calculation unit. On receiving the impedance measurement instruction from the FC outlet temperature change speed detection unit, the impedance calculation unit performs the impedance measurement for the second time. In consequence, it is possible to realize such scavenging control as to keep the water content of a fuel cell at an appropriate level by the minimum number of impedance measurement times (e.g., twice).

Abstract: A fuel cell system has a flooding elimination mode as one of available operation modes of fuel cells and includes a drive controller. When the ambient temperature of the fuel cell system is not higher than a preset first temperature, the drive controller causes the fuel cells to be driven in the flooding elimination mode. When the ambient temperature of the fuel cell system is not lower than a preset second temperature that is higher than the first temperature, the drive controller prohibits the fuel cells from being driven in the flooding elimination mode. On the occasion of input of a checkup instruction of the fuel cells, the drive controller causes the fuel cells to be driven in the flooding elimination mode, independently of the ambient temperature. This arrangement effectively improves the user's convenience at the checkup time of the fuel cell system having the operation mode for eliminating the state of flooding.

Abstract: A fuel cell system has a fuel cell stack generating electricity with a reactive gas supplied thereto and a controller supplying to the fuel cell stack the reactive gas whose pressure is higher than a normal operational pressure on condition that a temperature of the fuel cell stack is equal to or less than a predetermined threshold temperature and that a moisture content of the fuel cell stack is equal to or less than a predetermined threshold value. Where a supply pressure of the reactive gas is raised, an amount of moisture taken away by the reactive gas becomes less, and thus, water balance within the fuel cell stack shifts toward accumulation of moisture contained in the reactive gas into the film-electrode joined body. However, since the moisture content of the fuel cell stack is equal to or less than the predetermined threshold value, the system can improve the starting performance of the fuel cell stack at low temperature while suppressing flooding.

Abstract: A gas detection system functions to detect a specific gas present in a certain space. The gas detection system includes a gas concentration detector arranged to detect concentration of the specific gas as a gas concentration. The gas detection system also has a determination module configured to determine whether the gas concentration detected by the gas concentration detector exceeds a set threshold value. In response to input of a checking instruction for checking up the gas concentration detector into the determination module, the determination module uses a threshold value for checkup purpose, in place of the set threshold value. This arrangement effectively enhances the convenience in the process of checking up the gas concentration detector.

Abstract: To quickly and optimally control the water condition and temperature of a fuel cell even when the fuel cell is at a low temperature and in a dry state. If it is determined that a fuel cell is in a dry state and is determined that the fuel cell is at a low temperature, a control device performs low-efficiency power generation. Performing the low-efficiency power generation makes it possible to quickly warm up the fuel cell and bring the cathode water balance of a fuel cell into a plus (wet) state, so that the water condition and temperature of the fuel cell can be quickly and optimally controlled.

Abstract: In a fuel cell system, it is possible to suppress fixation of a fluid circulating device arranged in a fluid passage connected to a fuel cell main body. The fuel cell system is provided with a fuel cell stack, a system main body having respective elements for supplying a fuel gas and respective elements for supplying an oxidizing gas, and a control device. The control device includes a fluid circulating device drive processing unit having a function to forcibly drive the fluid circulating device after determining, based on a judgment related to one or more of a non-use time, an operation state of the system main body, a membrane impedance state of a fuel cell, a temperature of the fuel cell stack, and a background noise, whether or not forced driving to suppress sticking of the fluid circulating device is preferable at that time.

Abstract: A fuel cell system includes a power supply controller. In response to input of a first command prior to a start of fuel cells in a state of power supply from a power source to fuel cell-related auxiliary machinery, the power supply controller reduces an amount of electric power supplied to the fuel cell-related auxiliary machinery until input of a start instruction to start the fuel cells. In response to input of a second command, the power supply controller instructs to continue the power supply from the power source to the fuel cell-related auxiliary machinery without reducing the electric power level of the power supply, irrespective of the input or non-input of the first command. The fuel cell system of this arrangement effectively reduces the amount of electric power consumed by an electricity storage device before a start of the fuel cells.

Abstract: A gas detection system is configured to detect a preset gas in a predetermined space. The gas detection system includes a gas concentration detector constructed to detect a gas concentration of the preset gas, a recording assembly, a notification module, and a decision module. When the gas concentration detected by the gas concentration detector is higher than a preset first reference value, the decision module controls the notification module to give notice. When the detected gas concentration is higher than a preset second reference value but is lower than the preset first reference value, on the other hand, the decision module controls the notification module to give no notice but record a specific piece of information into the recording assembly. This arrangement of the gas detection system enables the user to readily detect deterioration of a device utilizing a fuel, for example, fuel cells.

Abstract: A fuel cell system comprises a fuel cell, a reactant gas supply device, and a capacitor which supplies a power to various devices when the fuel cell is in a temporary power generation stop state. The fuel cell system drives the reactant gas supply device based on a predetermined current instruction value to supply a reactant gas to the fuel cell, thereby generating the power. Such a fuel cell system comprises a control device which judges whether or not the current instruction value is below a water balance zero current value when the water content of the fuel cell is below a predetermined threshold and the stored electric charge of the capacitor is a predetermined threshold or more. If affirmative judgment is obtained, the control device switches the power generation state of the fuel cell to the temporary power generation stop state.

Abstract: There is disclosed a fuel cell system capable of appropriately performing the impedance measurement and scavenging control of a fuel cell during the stop of the fuel cell system. According to the present embodiment, in the fuel cell system including a control section which monitors and controls the state of a fuel cell, the control section stops the supply of a fuel gas to the fuel cell, then executes scavenging process to discharge, from the system, a water content in the fuel cell, and intermittently measures the impedance of the fuel cell during the scavenging process of the fuel cell, and the control section is characterized in that the fuel gas is intermittently supplied to the fuel cell during the scavenging process of the fuel cell.

Abstract: A fuel cell system includes: a fuel cell stack for generating electric power by receiving supply of a reaction gas; an air compressor for scavenging water remaining in the fuel cell stack when power generation is stopped; a rechargeable battery for supplying electric power to the air compressor for operation thereof; and a controller for estimating an amount of water remaining in the fuel cell stack based on an alternating-current impedance of the fuel cell stack, estimating a target SOC for charging the rechargeable battery with electric power required for scavenging the amount of water, and controlling charge and discharge so that an SOC of the rechargeable battery agrees with the target SOC.

Abstract: The measurement precision of a current detector of the fuel cell in a fuel cell system is improved. Where the fuel cell system 20 has not started operation, the vehicle 10 is operating under regenerative operation, the fuel cell 21 is operating under intermittent operation, or operation of the fuel cell system 20 has ended, the output terminal voltage of the fuel cell 21 is set to the OCV value of 400V via the DC/DC converter 31. As a result, even where the status of the fuel cell 21 changes from operating to stopped, the value of the current flowing over the power supply lines 411 can be immediately and reliably set to 0 A. The control unit 60 then obtains the current value Ad from the fuel cell current sensor 413 (step S150), and determines the offset correction value Ac needed in order to cancel the drift amount (i.e., in order to perform zero-point correction).

Abstract: According to the invention, a hybrid fuel cell system (100) is characterized by comprising a load portion (3) which consumes electric power; first control means (11) for obtaining a supply electric power set value (P bat ref) indicating electric power supplied from the electric power storage device (40), based on a supply electric power set value (P fc ref) indicating electric power supplied from the fuel cell (20) and a consumption electric power set value (P mot ref) indicating electric power consumed by the load portion (3); difference obtaining means (41) for obtaining a difference between the supply electric power set value (P bat ref) and an actual supply electric power value (P bat mos) indicating electric power actually supplied from the electric power storage device (40); and second control means (12) for controlling the amount of electric power consumed by the load portion (3) based on the difference.

Abstract: A control device receives a power supply current from a current sensor and a reactor current from a current sensor and detects a maximum value and a minimum value from the reactor current and from the detected maximum and minimum values and the power supply current determines whether the reactor current traverses the zero point, and if so the control device generates and outputs a signal to an up converter which responds to the signal by stopping switching to perform an up or down converting operation.

Abstract: A fuel battery system capable of quickly consuming residual hydrogen gas even if a surplus power consumption means has a limitation. During shutdown of the system, a fuel battery (10) is made to generate power by using the surplus fuel gas to charge a secondary battery (41), and non-storable surplus power is consumed by consumption means (22, 33, 13). When the surplus power generated by the fuel cell is consumed by the consumption means, any limitation in the system is detected, and the power generated by the fuel battery is changed depending on the detected limitation.

Abstract: A control device receives a power supply current from a current sensor and a reactor current from a current sensor and detects a maximum value and a minimum value from the reactor current and from the detected maximum and minimum values and the power supply current determines whether the reactor current traverses the zero point, and if so the control device generates and outputs a signal to an up converter which responds to the signal by stopping switching to perform an up or down converting operation.

Abstract: The measurement precision of a current detector of the fuel cell in a fuel cell system is improved. Where the fuel cell system 20 has not started operation, the vehicle 10 is operating under regenerative operation, the fuel cell 21 is operating under intermittent operation, or operation of the fuel cell system 20 has ended, the output terminal voltage of the fuel cell 21 is set to the OCV value of 400V via the DC/DC converter 31. As a result, even where the status of the fuel cell 21 changes from operating to stopped, the value of the current flowing over the power supply lines 411 can be immediately and reliably set to 0 A. The control unit 60 then obtains the current value Ad from the fuel cell current sensor 413 (step S150), and determines the offset correction value Ac needed in order to cancel the drift amount (i.e., in order to perform zero-point correction).

Abstract: The invention constructs a system which vaporizes a liquid raw material in a vaporizing section and steam-reforms the vaporized raw material in a reforming section to generate hydrogen. A pressure regulating valve for regulating the pressure in the vaporizing section is disposed at anywhere from the vaporizing section to downstream of the reforming section. When a hydrogen requirement is increased, the pressure regulating valve is controlled to decrease the pressure in the vaporizing section. The pressure reduction makes it possible to promote vaporization in the vaporizing section such that the rate of generation of steam can be improved. Moreover, during start-up of the system, the control mode is changed to open the pressure regulating valve, thereby limiting the rate of increase in pressure just after the generation of reformed gas has started.

Abstract: The invention constructs a system which vaporizes a liquid raw material in a vaporizing section and steam-reforms the vaporized raw material in a reforming section to generate hydrogen. A pressure regulating valve for regulating the pressure in the vaporizing section is disposed at anywhere from the vaporizing section to downstream of the reforming section. When a hydrogen requirement is increased, the pressure regulating valve is controlled to decrease the pressure in the vaporizing section. The pressure reduction makes it possible to promote vaporization in the vaporizing section such that the rate of generation of steam can be improved. Moreover, during start-up of the system, the control mode is changed to open the pressure regulating valve, thereby limiting the rate of increase in pressure just after the generation of reformed gas has started.