Abstract: The invention is provided to reliably restore generated voltage that has declined due to clogging of water in a fuel cell stack. A method of operating a fuel cell system having a fuel cell stack that generates electricity through an electrochemical reaction between a fuel gas including hydrogen gas and an oxidation gas, wherein when a generated voltage of the fuel cell stack declines, the water-in-cell content of the fuel cell stack is adjusted so that a variation in cell pressure loss in the fuel cell stack decreases based on a characteristic curve of the water-in-cell content of the fuel cell stack and the cell pressure loss of the fuel cell stack.

Abstract: In order to cause a plurality of cells in a fuel cell to be recovered to a desired humidity state, it is configured to determine that the cells present a mixture of dry and overly humid states in the case where a predetermined condition is satisfied, and in the case where it is determined that the cells present the mixture, humidifying control is carried out to cause all the cells to attain the overly humid state, and thereafter, drying control is carried out to dry all the cells, to thereby cause the plurality of cells to be recovered to a predetermined humidity state.

Abstract: The invention is provided to reliably restore generated voltage that has declined due to clogging of water in a fuel cell stack. A method of operating a fuel cell system having a fuel cell stack that generates electricity through an electrochemical reaction between a fuel gas including hydrogen gas and an oxidation gas, wherein when a generated voltage of the fuel cell stack declines, the water-in-cell content of the fuel cell stack is adjusted so that a variation in cell pressure loss in the fuel cell stack decreases based on a characteristic curve of the water-in-cell content of the fuel cell stack and the cell pressure loss of the fuel cell stack.

Abstract: In order to cause a plurality of cells in a fuel cell to be recovered to a desired humidity state, it is configured to determine that the cells present a mixture of dry and overly humid states in the case where a predetermined condition is satisfied, and in the case where it is determined that the cells present the mixture, humidifying control is carried out to cause all the cells to attain the overly humid state, and thereafter, drying control is carried out to dry all the cells, to thereby cause the plurality of cells to be recovered to a predetermined humidity state.

Abstract: A sealing device for being mounted on a piston which is movably fitted within a cylinder, includes a sealing ring member having opposite end portions which are interlocked with each other along the circumferential direction of the sealing ring member, and an expanding device for expanding the radius of sealing ring member in the radial direction thereof.

Abstract: A Stirling engine seal assembly includes a seal ring body and an expander. The seal ring body consists of a matrix made of polytetrafluoroethylene compounded and filled with carbon fibers and at least one powder selected from the group consisting of carbon powder, boron nitride powder and molybdenum disulfide powder. The plate expander is in abutting contact with the inner peripheral surface of the seal ring body for urging the seal ring body in the direction of its outer circumference.

Abstract: A sealing mechanism in a Stirling engine comprising, an output deriving device, a rod for connecting an operating piston defining an operating space and the output deriving device, an intermediate member for supporting the rod in fluid-tight manner via a bush, a sealing member secured to the intermediate member and including a lip in elastic engagement with the rod for assuring a fluid-tight fit, an intermediate chamber defined between the sealing member and the operating piston, a pressure chamber defined between the sealing member and the intermediate member, a first check-valve allowing fluid-flow from the intermediate chamber to the pressure chamber and a relief valve to be opened for releasing the pressure in the pressure chamber into a space for accommodating the output deriving device when the differential pressure exceeds a predetermined value.

Abstract: The present invention relates to a sealing device provided between a piston rod of a Stirling cycle engine and a variable volume chamber. The sealing device is provided with an arrangement so as to equalize pressures between a seal chamber and the variable volume chamber of the Stirling cycle engine. By equalizing pressures between the respective spaces, an overpressure is prevented which would otherwise distort the seal and permit oil to be carried into the working volume of the Stirling cycle engine.