Abstract: At a position between a fuel offgas inlet portion and a fuel gas inlet portion in a main body portion in the facing direction where a first end faces a second end, a fluid confluence joint is provided with at least either one of (i) at least one step formed over a whole circumference of an inner wall of the main body portion by reducing the passage sectional area on a fuel gas passage portion side to be smaller than the passage sectional area on a confluence passage portion side, and (ii) at least one partition wall formed over the whole circumference so as to project inwardly from the inner wall of the main body portion.

Abstract: At a position between a fuel offgas inlet portion and a fuel gas inlet portion in a main body portion in the facing direction where a first end faces a second end, a fluid confluence joint is provided with at least either one of (i) at least one step formed over a whole circumference of an inner wall of the main body portion by reducing the passage sectional area on a fuel gas passage portion side to be smaller than the passage sectional area on a confluence passage portion side, and (ii) at least one partition wall formed over the whole circumference so as to project inwardly from the inner wall of the main body portion.

Abstract: A fuel cell system includes: a gas exhaust flow path extended in a stacking direction of laminates and configured to have one end located inside a fuel cell stack and the other end located outside the fuel cell stack; and a water discharge flow path provided at a lower position than the gas exhaust flow path and formed to pass through at least part of the laminates. The gas exhaust flow path is interconnected with the water discharge flow path via at least one connecting section in the fuel cell stack. The gas exhaust flow path includes a narrowed flow path having the smaller sectional area than the sectional area of an adjacent flow path in downstream of the connecting section. The water discharge flow path has a downstream end connecting with the narrowed flow path.

Abstract: A fuel cell system 1000 includes: a gas exhaust flow path M2, 252 extended in a stacking direction of laminates 10 and configured to have one end located inside a fuel cell stack 100 and the other end located outside the fuel cell stack 100; and a water discharge flow path M3, 254 provided at a lower position than the gas exhaust flow path M2, 252 and formed to pass through at least part of the laminates 10. The gas exhaust flow path M2, 252 is interconnected with the water discharge flow path M3, 254 via at least one connecting section Mco in the fuel cell stack 100. The gas exhaust flow path M2, 254 includes a narrowed flow path 251 having the smaller sectional area than the sectional area of an adjacent flow path in downstream of the connecting section Mco. The water discharge flow path M3, 254 has a downstream end R1 connecting with the narrowed flow path 251.

Abstract: An internal state monitoring device for a fuel cell having multiple separators and an electrolyte sandwiched therebetween includes multiple electrodes for electrical conduction with multiple regions on a surface of a first separator at prescribed contact points in the fuel cell, a collecting portion for collecting currents flowing through the electrodes to give them the same electric potential, sensors for measuring the currents flowing through the electrodes, a load device connected to the fuel cell via the collecting portion and a second separator for variably controlling a load applied between the collecting portion and the second separator, and an extracting-monitoring device for extracting alternating current components, contained in each of the measured electrode currents, generated in response to a change in the load and monitoring the distribution of a state quantity of resistance polarization in the fuel cell based on each of the extracted alternating current components.

Abstract: A fault detecting apparatus for a gas concentration sensor is provided. The apparatus includes a storage device and a fault detecting circuit. The storage device stores therein fault detectable conditions in which preselected different types of faults of the gas concentration sensor are allowed to be detected, respectively. The fault detecting circuit works to detect a selected one of the faults stored in said storage device. When one of the fault detectable conditions is encountered during operation of the gas concentration sensor, the fault detecting circuit initiates detection of a corresponding one of the faults based on an output of the gas concentration sensor, thereby enabling the fault detecting circuit to identify the type of one of the faults to be detected correctly.

Abstract: A gas concentration measuring apparatus has a gas sensor consisting of pump, sensor, and monitor cells. The apparatus works to determine the value of voltage applied to the pump cell when a change in current produced by the monitor cell or the sensor cell changes upon a change in the voltage applied to the pump cell varies greatly and uses it to determine a control point to which the voltage applied to the pump cell is to be controlled. This keeps a gas concentration measuring accuracy free from, for example, aging of the sensor.

Abstract: A gas concentration measuring apparatus has a gas sensor including pump, sensor, and monitor cells. The apparatus works to look up a predetermined voltage-to-current relation to determine an initial value to be applied to the pump cell as a function of a current output of the pump cell, apply the initial value of the voltage to the pump cell, and to sweep it temporarily. The apparatus works to correct the initial value of the voltage as a function of a current output of the sensor cell upon the sweep of the initial value of the voltage applied to the pump cell, thereby better maintaining gas concentration measuring accuracy with respect to, for example, aging of the sensor.

Abstract: A fault detecting apparatus for a gas concentration sensor is provided. The apparatus includes a storage device and a fault detecting circuit. The storage device stores therein fault detectable conditions in which preselected different types of faults of the gas concentration sensor are allowed to be detected, respectively. The fault detecting circuit works to detect a selected one of the faults stored in said storage device. When one of the fault detectable conditions is encountered during operation of the gas concentration sensor, the fault detecting circuit initiates detection of a corresponding one of the faults based on an output of the gas concentration sensor, thereby enabling the fault detecting circuit to identify the type of one of the faults to be detected correctly.

Abstract: A gas concentration measuring apparatus has a gas sensor consisting of pump, sensor, and monitor cells. The apparatus works to determine the value of voltage applied to the pump cell when a change in current produced by the monitor cell or the sensor cell changes upon a change in the voltage applied to the pump cell varies greatly and uses it to determine a control point to which the voltage applied to the pump cell is to be controlled. This keeps a gas concentration measuring accuracy free from, for example, aging of the sensor.

Abstract: A gas concentration measuring apparatus has a gas sensor consisting of pump, sensor, and monitor cells. The apparatus works to look up a predetermined voltage-to-current relation to determine an initial value to be applied to the pump cell as a function of a current output of the pump cell, apply the initial value of the voltage to the pump cell, and to sweep it temporarily. The apparatus works to correct the initial value of the voltage as a function of a current output of the monitor cell upon the sweep of the initial value of the voltage applied to the pump cell, thereby keeping a gas concentration measuring accuracy free from, for example, aging of the sensor.