Abstract: A fuel cell system acquires an operation state of a fuel cell and estimates an IV characteristic that indicates a relationship between a current and a voltage in the fuel cell. At least one of a resistance overvoltage, an activation overvoltage, a current-voltage hysteresis and a concentration overvoltage of the fuel cell is determined from the operation state of the fuel cell, and the IV characteristic is estimated based on the determined result.

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: FC current control in a fuel cell operation system can be roughly divided into two parts. The first part executes a total air feed amount calculation step, an FC air amount calculation step, and a bypass air amount calculation step. These steps are executed by using a stoichiometry map and a pumping hydrogen amount map. The second part calculates a control valve open amount instruction value and a bypass valve open amount instruction value according to the calculated FC air amount and the bypass air amount. Here, a control valve open amount map and the like are used. When generated power is output from the fuel cell stack by these instruction values, the actual FC current value is compared to the FC current instruction value and the control valve open amount is corrected according to a difference between them.

Abstract: A fuel cell system acquires an operation state of a fuel cell and estimates an IV characteristic that indicates a relationship between a current and a voltage in the fuel cell. At least one of a resistance overvoltage, an activation overvoltage, a current-voltage hysteresis and a concentration overvoltage of the fuel cell is determined from the operation state of the fuel cell, and the IV characteristic is estimated based on the determined result.

Abstract: An air conditioning control system having a cooling device for cooling a fuel cell by circulating a liquid coolant through the fuel cell using a main circulation pump while also providing an air conditioning control device for controlling air conditioning in a vehicle interior, wherein heat exchange between the cooling device and the air conditioning control device is possible. When the fuel cell is operated intermittently in the air conditioning control system, the main circulation pump is continuously operated.

Abstract: A fuel cell operating system which can prevent freezing of a valve and a method of preventing fixation of the valve in the fuel cell operating system are provided. In steps of the process of preventing freezing of a valve in the present invention, first, supply of hydrogen, which is a fuel gas, is stopped. Power generation is continued in a fuel cell stack until the fuel gas which has already been supplied is consumed by the fuel cell reaction. It is constantly judged whether or not the power generation is stopped. When it is judged that the power generation is stopped, a function of a water discharge process module executes a process to open a bypass valve. When the bypass valve is opened, a large amount of pressurized air is supplied to a bypass flow path, and water present in the bypass flow path and water present in an exit-side flow path are forcibly pushed and discharged.

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: A fuel cell operating system which can prevent freezing of a valve and a method of preventing fixation of the valve in the fuel cell operating system are provided. In steps of the process of preventing freezing of a valve in the present invention, first, supply of hydrogen, which is a fuel gas, is stopped. Power generation is continued in a fuel cell stack until the fuel gas which has already been supplied is consumed by the fuel cell reaction. It is constantly judged whether or not the power generation is stopped. When it is judged that the power generation is stopped, a function of a water discharge process module executes a process to open a bypass valve. When the bypass valve is opened, a large amount of pressurized air is supplied to a bypass flow path, and water present in the bypass flow path and water present in an exit-side flow path are forcibly pushed and discharged.

Abstract: An air conditioning control system having a cooling device for cooling a fuel cell by circulating a liquid coolant through the fuel cell using a main circulation pump while also providing an air conditioning control device for controlling air conditioning in a vehicle interior, wherein heat exchange between the cooling device and the air conditioning control device is possible. When the fuel cell is operated intermittently in the air conditioning control system, the main circulation pump is continuously operated.

Abstract: FC current control in a fuel cell operation system can be roughly divided into two parts. The first part executes a total air feed amount calculation step, an FC air amount calculation step, and a bypass air amount calculation step. These steps are executed by using a stoichiometry map and a pumping hydrogen amount map. The second part calculates a control valve open amount instruction value and a bypass valve open amount instruction value according to the calculated FC air amount and the bypass air amount. Here, a control valve open amount map and the like are used. When generated power is output from the fuel cell stack by these instruction values, the actual FC current value is compared to the FC current instruction value and the control valve open amount is corrected according to a difference between them.

Abstract: The pressure sensor device has a laminated diaphragm (12) in which a strain resistance gauge is formed in a surface and a stopper member (13) including a concave portion forming a curved surface parallel to a surface formed by displacement of the diaphragm, the concave portion being disposed to face the diaphragm. Specifically, the concave portion of the stopper member is formed into a curved surface in which depth y at a distance x from the center of the diaphragm is expressed by a quartic function [y=pr4(1?x2/r2)2/64D] in relation to the operating pressure for protection against maximum pressure p when the diaphragm has a radius of r, a thickness of t, and a flexural rigidity of D.

Abstract: The pressure sensor device has a laminated diaphragm (12) in which a strain resistance gauge is formed in a surface and a stopper member (13) including a concave portion forming a curved surface parallel to a surface formed by displacement of the diaphragm, the concave portion being disposed to face the diaphragm. Specifically, the concave portion of the stopper member is formed into a curved surface in which depth y at a distance x from the center of the diaphragm is expressed by a quartic function [y=pr4(1?x2/r2)2/64D] in relation to the operating pressure for protection against maximum pressure p when the diaphragm has a radius of r, a thickness of t, and a flexural rigidity of D.