Abstract: A fuel cell system is provided with a water tank, a reformer obtaining reformed gas by reforming a fuel using water from the water tank, and a condenser reclaiming water from the exhaust gas from the condenser and return the water to the water tank. A method for controlling operating pressure is applied to such a fuel cell system. Here, in response to the exhaust temperature of the condenser, the equillibrium operating pressure of the fuel cell system at which the water inflow and outflow in the fuel cell system are balanced is calculated, and the maximum efficiency operating pressure at which the operating efficiency of the fuel cell system is maximum is calculated. Control is performed of the operating pressure of the fuel cell system so that it is the higher pressure of the equillibrium operating pressure and the maximum efficiency operating pressure.

Abstract: A fuel cell vehicle drives a motor (9) with electric power from a fuel cell power system (100) comprising a fuel cell (4) which generates electricity using hydrogen and oxygen. A controller (10) calculates an electrical load demand required to run the vehicle. When this value is below a predetermined load, it performs constant load operation of the fuel cell power system (100), and when the predetermined load value is exceeded, it operates it under a load according to the electrical load demand. The demand for resolution and precision of the various sensors or flowrate control valves installed in the fuel cell power system and thereby suppressed, costs can be reduced, and fuel cost-performance is improved by continuing an efficient operating state.

Abstract: A CO sensor (250) which detects CO contained in the air supplied to a fuel cell (200) by a compressor (202), and a sensor (206) which detects the state of charge (SOC) of a battery (207), are provided in a fuel cell vehicle. A controller (254) controls operation and stop of the fuel cell based on CO concentration and the state of charge of the battery (207), and stops operation of the fuel cell (200) at a lower CO concentration the higher the state of charge of the battery (207).

Abstract: The invention presents a fuel reforming technique for a mobile fuel cell system capable of obtaining a reformed gas composition usable in fuel cell 200 even if vapor temperature supplied from an evaporator 102 into a fuel reformer 107 varies significantly.

Abstract: When a kick-down operation by a driver is detected during the startup of a fuel reforming system, the amount of electrical power required for startup of the fuel reforming system is limited, and the amount of electrical power distributed to a motor is increased, thereby giving priority to powering the motor.

Abstract: A fuel cell system includes a fuel cell (9), an exhaust gas circulation passage (10) which circulates part of the exhaust gas from the fuel cell (9) back to the fuel cell (9), a fuel injector (3) which injects liquid fuel into the circulated exhaust gas, and a vaporizer (4) which vaporizes the injected fuel. The fuel cell system has a high response, as the liquid fuel injected into the exhaust gas rapidly vaporizes.

Abstract: A vehicle drive system includes a power generation device (150) which generates power using fuel, a battery (112) which stores the power generated by the power generation device, and a rotating machine (113) which drives the vehicle using the power supplied from the power generation device or the battery, and regenerates power when the vehicle is decelerating. A controller (115) computes a smoothed value of the electrical load of the vehicle, computes a running load command value supplied to the power generation device (150) based on the smoothed electrical load value, computes the power regenerated by the rotating machine (113), corrects the running load command value based on the regenerated power, and controls the power generation device (150) based on the corrected running load command value.

Abstract: A reformer (3) supplies a reformate gas to a fuel cell stack (4). The reformer (3) generates a reformate gas by reforming gaseous fuel vaporized by a vaporizer (2). When current supply from the fuel cell stack (4) to the electric motor (21) undergoes a sharp decrease, unnecessary consumption of gaseous fuel is prevented by closing a first valve (11) which supplies gaseous fuel from the vaporizer (2) to the reformer (3) and by opening a second valve (13) which returns gaseous fuel in the vaporizer (2) to the fuel tank (6).

Abstract: A reformer (2) produces a reformate gas by partial oxidation of vaporized fuel with air supplied through a first air supply passage (10A). A hydrogen-rich gas is produced by removing carbon monoxide from the reformate gas with a carbon monoxide oxidizer (3) and thereafter is supplied to the fuel cell stack (1). A second air supply passage (8A) which has a smaller cross sectional area than the first air supply passage (10A) is also provided to supply air to the reformer (2). When substantially no load is applied to the fuel cell stack (1), the first air supply passage (10A) is cut off with a valve (7A) and a minute amount of air is supplied to the reformer (2) from the second air supply passage (8A) to maintain a standby operation of the power plant in order to prevent reductions in the temperature of the fuel cell stack (1).

Abstract: High temperature reducing gas is supplied to a reforming catalyst (51) of a reformer (13) and a CO removal catalyst (52) of a CO removal device (15) from a start-up combustor (11). By supplying the high temperature reducing gas from the start-up combustor (11), there is no need to provide an additional device for supplying reducing gas, and the heat required for the reaction may be supplied simultaneously.

Abstract: A solid oxide fuel cell (SOFC) contains a first solid electrolyte layer of LaGa-based perovskite, an air electrode, a fuel electrode and a second solid electrolyte layer (having a hole transport number smaller than that of the first solid electrolyte layer), which is provided between the first solid electrolyte layer and an air electrode. Also, another SOFC contains a first solid electrolyte layer of LaGa-based perovskite, an air electrode, a fuel electrode and a third solid electrolyte layer (having electron and proton conductivity lower than that of the first solid electrolyte layer), which is provided between the first solid electrolyte layer and the fuel electrode. Still another SOFC contains the second solid electrolyte layer provided between a first solid electrolyte layer and an air electrode and the third solid electrolyte layer provided between the first solid electrolyte layer and a fuel electrode.

Abstract: Disclosed is a fuel cell system comprising a fuel tank 11 for storing fuel; an evaporator 12 for evaporating the fuel to generate fuel gas; a reforming reactor 13 for generating reforming gas containing hydrogen from the fuel gas; a combustor 14 for burning any one of the fuel and the reforming gas to supply heat to the evaporator 12; and a fuel cell portion 15 for generating electricity by use of the hydrogen contained in the reforming gas generated in the reforming reactor 13, wherein a boiling point temperature of the fuel in the evaporator 12 is estimated based on an operation pressure of the evaporator 12, a vapor temperature of the fuel gas in the evaporator 12 is measured, and when a value obtained by subtracting the boiling point temperature from the vapor temperature becomes below a predetermined value, a flow rate of any one of the fuel and the reforming gas burnt in the combustor 14 is increased.

Abstract: A fuel cell system includes an evaporator 80 composed of a cross type heat exchanger 16 adapted to produce fuel containing steam and methanol vapor that are evaporated with heating gas 18 exhausted from a combustor 20. The evaporator 80 has first and second heat exchanger sections 88 and 89 having respective evaporating heat transfer surfaces, and first and second liquid sump sections 82a and 84a formed in the vicinities of the respective heat transfer surfaces and having variable volumes, respectively. The evaporator 80 includes first and second volume control devices 90 and 92 that control the volumes of the liquid sump sections 82a and 84a such that fuel vapor is produced at a demanded amount to meet load variations of a vehicle.

Abstract: An etching process for a silicon semiconductor substrate to produce a semiconductor pressure sensor or a semiconductor acceleration sensor. The etching process comprises the following steps: (a) carrying out an etching of the semiconductor without application of a voltage to the semiconductor so as to accomplish a pre-etching step, the pre-etching step including dipping the semiconductor in hydrazine hydrate; and (b) carrying out an electrochemical etching of the semiconductor by applying pre-etching step so as to accomplish a final etching step, the final etching step including dipping the semiconductor in an alkali system etching solution containing at least hydrazine (N.sub.2 H.sub.4), potassium hydroxide (KOH), and water (H.sub.2 O), the alkali system etching solution containing potassium hydroxide in an amount of not less than 0.3% by weight.

Abstract: A method of producing a device having a minute structure such as a semiconductor element. The producing method comprises the following steps: (a) forming a film of liquid containing a sublimable material on a surface of a product of the device, the sublimable material being solid ordinary temperature and at normal pressure, the minute structure being formed at the surface of the product; (b) improving a wettability of at least one of the minute structure and a region surrounding the minute structure by the liquid film of the sublimable material; (c) converting the liquid film into a state containing the sublimable material in solid phase so as to form a protective film; and (d) vaporizing the protective film to be removed.

Abstract: An electrochemical etching process carried out in an etching system including an electrolysis vessel which is provided thereinside with facing wall surfaces defining therebetween an etching solution flow region. A semiconductor substrate to be etched and a counter electrode are mounted respectively on the facing wall surfaces. A flow stream generating section for the etching solution is formed separate from the etching solution flow region and includes a device for generating the flow stream of the etching solution. The flow stream generating section is connected to the etching solution flow region in such a manner that the etching solution flow in a direction generally parallel with the facing wall surfaces inside the electrolysis vessel. An electric potential is applied between the semiconductor substrate and the counter electrode to accomplish an electrochemical etching on the semiconductor substrate.

Abstract: A semiconductor device is produced through electrolytic etching process. The device comprises a P-type silicon substrate. An N-type epitaxial layer is formed on the silicon substrate. P-type regions are defined in the N-type epitaxial layer. N-type regions are defined in some of the P-type regions. A first wiring layer connects to predetermined ones of the P-type regions. A second wiring layer connects to predetermined ones of the N-type regions. The semiconductor device has a given part which has such a possibility that a predetermined magnitude of leakage current flows therethrough between the first and second wiring layers when subjected to the electrolytic etching process. The semiconductor device further has a circuit which is electrically connected to one of the first and second wiring layers. The circuit is capable of removing the possibility of the leakage current flow through the given part when opened.

Abstract: An etching device performing an etching process on a material immersed in a etchant which is a mixture of acids of which the main components are fluoric acid, nitric acid, and acetic acid. The etching device includes a semiconductor electrode immersed in the etchant, an opposing electrode immersed in the etchant, an electron meter for detecting an electric potential difference between the semiconductor electrode and the opposing electrode, and a controller for uniformly controlling the nitrite ion concentration in the etchant from the electric potential difference between the semiconductor electrode and the opposing electrode, detected by the electronmeter.

Abstract: Disclosed is a method of etching comprising preparing an etching solution containing hydrofluoric acid and nitric acid, and etching while adding nitrite ion or a medium for producing nitrite acid ion to the etching solution. As the medium for producing the nitrite ion, silicon with a high impurity concentration, a mixed acid solution containing hydrofluoric acid and nitric acid having been used for dissolving a great amount of silicon, or gaseous nitrogen dioxide may be used. Preferably, the concentration of nitrite ion in the etching solution is detected based on the concentration of NO.sub.x in the gas phase which is in an equilibrium relation to the nitrite ion in the liquid phase of the etching solution, and necessary nitrite ion are added to the etching solution based on the concentration of NO.sub.x.