Abstract: A fuel cell system includes: a fuel cell in which electrical power generation is performed through chemical reactions of reaction gases being supplied thereto; a discharge path through which the reaction gases are discharged; a discharge valve provided on the discharge path and operated for discharging the reaction gases through the discharge path; an opening condition monitoring device for continuously monitoring a demanded opening condition of the discharge valve; and an opening condition renewing device for renewing the demanded opening condition of the discharge valve depending on the demanded opening condition of the discharge valve detected by the opening condition monitoring device when opening of the discharge valve is demanded. Opening of the discharge valve is controlled depending on the latest demanded opening condition which has been renewed by the opening condition renewing device.

Abstract: A control device for a fuel cell including a transient state determination unit which determines whether changes in generated output of the fuel cell are within a predetermined range; a hydrogen purge detection unit which detects the presence/absence of a purge command to a hydrogen purge valve; a failure determination unit which determines, if the transient state determination unit determined that it is not a transient state, failure in the hydrogen purge valve based on an actual hydrogen pressure value at an inlet portion of the fuel cell and a target hydrogen pressure value, which is set in accordance with the presence/absence of the purge command detected by the hydrogen purge detection unit; and an alarm unit which generates an alarm when failure in the hydrogen purge valve is determined by the failure determination unit.

Abstract: A method for controlling the flow rate of an oxidizer in a fuel cell system having a fuel cell stack being supplied with fuel and the oxidizer, a compressor for supplying the oxidizer to the fuel cell stack, a back pressure valve for controlling pressure of the oxidizer, and a control device for controlling the fuel cell stack, the compressor, and the back pressure valve. The method includes the steps of calculating an oxidizer pressure command and an oxidizer flow rate command based on a given electrical current command, comparing a first flow rate that is defined as an upper limit of oxidizer flow rate and a second flow rate that is defined as a lower limit of oxidizer flow rate with the oxidizer flow rate command, and regulating the oxidizer flow rate command so as to be limited within a range from the second flow rate to the first flow rate.

Abstract: An oxidizing agent supply system failure determination method for a fuel cell for use with a fuel cell apparatus provided with a fuel cell that is supplied with a fuel and an oxidizing agent, and an oxidizing agent supply system that has an oxidizing agent condition adjusting means that adjusts condition of the oxidizing agent supplied to the fuel cell, comprising the step of determining that the oxidizing agent supply system has failed if an absolute value of a difference between an actual value of a supply provided by the oxidizing agent condition adjusting means and a first predetermined value that is compared to the actual value is equal to or greater than a second predetermined value and a predetermined period of time has passed. An oxidizing agent supply system failure determination method for a fuel cell is provided which can maintain the reliability of the fuel cell apparatus.

Abstract: A method for controlling the flow rate of an oxidizer in a fuel cell system having a fuel cell stack being supplied with fuel and the oxidizer, a compressor for supplying the oxidizer to the fuel cell stack, a back pressure valve for controlling pressure of the oxidizer, and a control device for controlling the fuel cell stack, the compressor, and the back pressure valve. The method includes the steps of calculating an oxidizer pressure command and an oxidizer flow rate command based on a given electrical current command, comparing a first flow rate that is defined as an upper limit of oxidizer flow rate and a second flow rate that is defined as a lower limit of oxidizer flow rate with the oxidizer flow rate command, and regulating the oxidizer flow rate command so as to be limited within a range from the second flow rate to the first flow rate.

Abstract: A fuel cell system comprises a fuel cell, a hydrogen discharge valve for discharging hydrogen from the fuel cell under a predetermined condition, a hydrogen concentration reduction device for reducing the concentration of hydrogen discharged from the hydrogen discharge valve, a hydrogen sensor for detecting an instantaneous hydrogen concentration of a gas processed by the hydrogen concentration reduction device and an average hydrogen concentration calculating unit for calculating an average hydrogen concentration per hour of a gas processed by the hydrogen concentration reduction device, wherein a hydrogen discharge from the fuel cell by the hydrogen discharge valve is prohibited in the event that an instantaneous hydrogen concentration detected by the hydrogen sensor exceeds a first threshold, or in the event that an average hydrogen concentration calculated by the average hydrogen concentration calculating unit exceeds a second threshold which is lower than the first threshold.

Abstract: A hydrogen purge control apparatus includes a fuel cell stack from which hydrogen is purged as necessary, a purged hydrogen dilution device which is disposed downstream of the fuel cell stack, and which has a chamber formed therein, a first inlet for purged hydrogen, a second inlet for air, and an outlet for diluted hydrogen, a regulator which is disposed between the fuel cell stack and the first inlet, and which is provided for regulating an amount of the purged hydrogen flowing into the purged hydrogen dilution device, and a control unit having a hydrogen concentration estimating section that is configured to estimate the hydrogen concentration at the outlet of the purged hydrogen dilution device based on an operating state of the fuel cell stack. The regulator is operated by the control unit depending on the hydrogen concentration estimated by the hydrogen concentration estimating section.

Abstract: A control system for a fuel cell includes a vapor generation unit, a fuel reforming unit, a fuel supply unit, a combustion unit, a fuel vapor temperature detection unit, a temperature detection unit, a current detection unit, and a control unit. The vapor generation unit produces a fuel vapor by vaporizing a liquid fuel. The fuel reforming unit reforms the fuel vapor to produce a hydrogen-enriched fuel. The fuel supply unit supplies the reformed fuel to the fuel cell. The control unit calculates quantity of heat retained by the vapor generation unit based on the temperature of the fuel vapor, the temperature of the combustion unit, and the generated current. The control unit also controls a fuel supply command value for the fuel supply unit and/or a current generation command value for the fuel cell based on the calculated quantity of heat retained by the vapor generation unit.

Abstract: A discharged fuel diluter includes: a retention region with a predetermined volume, into which a fuel discharged from a fuel cell is retained at the time of purging; a dilution region with a predetermined volume, through which air discharged from the fuel cell flows and at which the air is mixed with the fuel from the retention region to dilute the fuel; and a communicating portion, through which the fuel flows from the retention region to the dilution region.

Abstract: The invention detects quickly and with high precision abnormalities in fuel cells. In a method of detecting abnormalities in a fuel cell 1 comprising a plurality of unit cells that generate power by supplying hydrogen gas to an anode and supplying air to a cathode of each unit cell, the abnormality in the fuel cell 1 is detected based on the speed of the decrease in the cell voltages after stopping the fuel cell, i.e., after stopping the supply of the reacting gases to the fuel cell.

Abstract: A control device for a fuel cell including a transient state determination unit which determines whether changes in generated output of the fuel cell are within a predetermined range; a hydrogen purge detection unit which detects the presence/absence of a purge command to a hydrogen purge valve; a failure determination unit which determines, if the transient state determination unit determined that it is not a transient state, failure in the hydrogen purge valve based on an actual hydrogen pressure value at an inlet portion of the fuel cell and a target hydrogen pressure value, which is set in accordance with the presence/absence of the purge command detected by the hydrogen purge detection unit; and an alarm unit which generates an alarm when failure in the hydrogen purge valve is determined by the failure determination unit.

Abstract: A control system for a fuel cell includes a vapor generation unit, a fuel reforming unit, a fuel supply unit, a combustion unit, a fuel vapor temperature detection unit, a temperature detection unit, a current detection unit, and a control unit. The vapor generation unit produces a fuel vapor by vaporizing a liquid fuel. The fuel reforming unit reforms the fuel vapor to produce a hydrogen-enriched fuel. The fuel supply unit supplies the reformed fuel to the fuel cell. The control unit calculates quantity of heat retained by the vapor generation unit based on the temperature of the fuel vapor, the temperature of the combustion unit, and the generated current. The control unit also controls a fuel supply command value for the fuel supply unit and/or a current generation command value for the fuel cell based on the calculated quantity of heat retained by the vapor generation unit.

Abstract: A substrate or a ceramic package for packaging semiconductor chips, which comprises an insulating layer having a signal line on one surface of said insulating layer and a power line or ground line corresponding to said signal line on the other surface of said insulating layer. A well-controlled constant high frequency characteristics, and particularly, characteristic impedance, can be obtained on the signal line without being influenced by the power line or ground line.

Abstract: A method of mounting an electronic part having a terminal portion on a board on which a circuit including a connection portion is formed. It includes a process of forming a conductive layer on the surface of the terminal portion; a process of forming, on the surface of the connection portion, a conductive layer having a melting point different from that of the conductive layer formed on the surface of the terminal portion; and a process of melting the conductive layer having a low melting point in such a state that the conductive layer of the terminal portion is contacted with the conductive layer of the connection portion, thereby fusing the conductive layer having a low melting point onto the conductive layer having a high melting point.

Abstract: A thermoplastic elastomer composition comprising (A) 10-90 parts by weight of crystalline polypropylene, (B) 10-90 parts by weight of brominated butyl rubber, (C) 10-120 parts by weight of olefinic copolymer rubber to 100 parts by weight of (A)+(B), and (D) 10-150 parts by weight of process oil as plasticizer to 100 parts by weight (A)+(B), all of which are dynamically vulcanized in the presence of a peroxide crosslinking agent.The thermoplastic elastomer composition of this invention has a high gel ratio or gel content in part because brominated butyl rubber is vulcanized with peroxide. The composition has good elasticity, high mechanical strength, low compressively permanent set, excellent long-term heat stability, moldability, and gas impermeability and high damping characteristic.

Abstract: A ferromagnetic resonance device is disclosed which utilize the perpendicular resonance of ferrimagnetic YIG thin film operable under a D.C. bias magnetic field perpendicular to a major surface of the YIG thin film element. By making the YIG thin film to have a major surface thereof (100) crystal plane of YIG or (111) crystal plane of a substituted YIG having reduced Ku value, lower limit of resonance frequency is extremely lowered. Thus wide range variable filter device can be obtained.

Abstract: In a thin film ferromagnetic resonance tuned filter is disclosed which comprises a ferrimagnetic thin films, input and output signal transmission lines respectively coupled with the ferrimagnetic thin films, and a magnetic circuit for applying a DC magnetic field to the ferrimagnetic thin films, the present invention expands the variable frequency band by forming extensions each extending from the signal transmission line so that the distance from the coupling point of the signal transmission line coupled with the corresponding ferrimagnetic thin film to the grounded end thereof is 1/10 or above and less than 1/4 the wavelength of a wave transmitted in the transmission lines at the upper limit frequency of a tuning frequency band. Further the deterioration of the isolation characteristics is suppressed by bending the extended portions not to form parallel portions to another transmission line.

Abstract: A tuned oscillator utilizing a thin film ferromagnetic resonator is disclosed. The oscillator comprises an active element for oscillator and a YIG thin film resonator connected to the active element as a part of feed-back circuit for the active element. The YIG thin film resonator is applied with a bias magnetic field perpendicular to a surfce of a YIG disk which is generated by a permanent magnet for a fixed component and a coil for a variable component for the resonance frequency. The resonance frequency is stabilized by use of a PLL circuit connected to an output of the oscillator and feeding back to the coil. Since the YIG thin film tuned oscillator has a high Q value, high quality communication signal processing can be achieved. The YIG tuned oscillator is used as local oscillator for a transciever.

Abstract: A tuned oscillator is disclosed which consists of an active element for oscillation, a ferrimagnetic resonant element connected to part of feedback of the active element, and a matching circuit connected to the active element. The matching cirucit is designed to reflect the fundamental wave produced by the ferrimagnetic resonant element and active and pass the second harmonic wave. Consequently, the magnetic circuit has its load reduced in applying a D.C. magnetic field necessary for frequency tuning to the ferrimagnetic resonance element.

Abstract: A ferromagnetic resonator is disclosed, in which perpendicular ferrimagnetic resonance of thin film YIG is utilized. The resonator comprises a ferrimagnetic YIG thin film and a microstrip line coupled to the YIG thin film operative in a bias magnetic field applied perpendicular to a major surface of the YIG thin film. The YIG thin film disk has a magnetization distribution of magnetostatic mode, and the microstrip line is designed to generate a high-frequency magnetic field distribution similar to the magnetization distribution of the uniform mode (1, 1).sub.1. In such arrangement, coupling between the high-frequency magnetic field and magnetization of high sprious mode is reduced.