Abstract: A fuel cell system includes a fuel cell in which cells are stacked, a voltage sensor that detects a voltage in unit of one or more of the cells, a control unit that determines an operating point of the fuel cell and causes the fuel cell to operate. The control unit causes the fuel cell to operate at a low efficiency operating point having a lower efficiency than an efficiency of a reference operating point in a warm-up operation. In the warm-up operation, the control unit calculates a total number of the cells in which the voltage detected by the voltage sensor is equal to or less than a predetermined first reference voltage and calculates an exhaust hydrogen concentration based on the total number or the cells.

Abstract: A fuel cell system includes a fuel cell, a hydrogen tank, a hydrogen supply passage connecting the hydrogen tank and the fuel cell, a cutoff valve configured to cut off circulation of hydrogen in the hydrogen supply passage, a detection unit configured to detect a start of filling of the hydrogen tank with hydrogen, and a purge controller configured to close the cutoff valve in a case where the fuel cell system is stopped and the detection unit detects the start of filling with hydrogen in a state in which purge processing of purging the in-cell hydrogen flow passage is to be executed, and to execute processing of purging the in-cell hydrogen flow passage by causing hydrogen remaining on a downstream side of the cutoff valve in a hydrogen flow in the hydrogen supply passage to flow in the in-cell hydrogen flow passage as the purge processing.

Abstract: A fuel cell system comprises: a gas-liquid separator separating exhaust gas of a fuel cell stack into a liquid component and a gas component and storing liquid water of the liquid component; a circulation pipe; a drain pipe discharging the liquid water; and a drain valve opening and closing the drain pipe. In an end scavenging process that is executed when operation of the fuel cell system is finished, the control unit opens the drain valve when a valve opening condition for the drain valve is satisfied. The valve opening condition is set such that an amount of the liquid water stored in the gas-liquid separator at the time the drain valve is opened in the end scavenging process is larger than an amount of the liquid water stored in the gas-liquid separator at the time the drain valve is opened during normal operation of the fuel cell system.

Abstract: A fuel cell system comprises a fuel cell; a reactive gas supply mechanism configured to supply a reactive gas to the fuel cell; a discharge flow path configured to discharge an off-gas and water discharged from the fuel cell; a valve provided in the discharge flow path; a remaining water purging controller configured to control a remaining water purging process of the fuel cell by using the reactive gas supply mechanism and the valve; a heating portion configured to heat the valve; and a failure detector configured to detect a failure of the heating portion. When a failure of the heating portion is detected, the remaining water purging controller performs the remaining water purging process and increases a water discharge power in the remaining water purging process than a water discharge power in the remaining water purging process performed when no failure of the heating portion is detected.

Abstract: A fuel cell system includes a fuel cell stack having a plurality of cells each having hydrogen channels, a hydrogen channel inlet, and a hydrogen channel outlet, a load supplied with power from the fuel cell stack, a circulation passage connecting the channel inlet with the channel outlet, a hydrogen pump provided in the circulation passage, and a controller. The controller rotates the hydrogen pump in a positive direction so as to feed the hydrogen gas in a first amount into each cell through the channel inlet, at a flow rate larger than a minimum flow rate required for power generation, and then rotate the hydrogen pump in a negative direction so as to feed the hydrogen gas into each cell through the channel outlet, during a period from stop of power supply to the load, to the next start of power supply.

Abstract: Provided is a fuel cell system that can effectively suppress clogging of a pipe due to freezing of water in a fuel gas supply system thereof without the need for halting the operation of the fuel cells, and thus is highly reliable. When possible freezing of water is detected or presumed to be present downstream of an injector, the amount of a fuel gas to be supplied from a circulation pump that is disposed in a circulation channel is relatively increased compared to the amount of the fuel gas to be supplied from the injector.

Abstract: A fuel cell system includes a fuel cell stack having a plurality of cells each having hydrogen channels, a hydrogen channel inlet, and a hydrogen channel outlet, a load supplied with power from the fuel cell stack, a circulation passage connecting the channel inlet with the channel outlet, a hydrogen pump provided in the circulation passage, and a controller. The controller rotates the hydrogen pump in a positive direction so as to feed the hydrogen gas in a first amount into each cell through the channel inlet, at a flow rate larger than a minimum flow rate required for power generation, and then rotate the hydrogen pump in a negative direction so as to feed the hydrogen gas into each cell through the channel outlet, during a period from stop of power supply to the load, to the next start of power supply.

Abstract: A fuel cell system comprises a fuel cell; a reactive gas supply mechanism configured to supply a reactive gas to the fuel cell; a discharge flow path configured to discharge an off-gas and water discharged from the fuel cell; a valve provided in the discharge flow path; a remaining water purging controller configured to control a remaining water purging process of the fuel cell by using the reactive gas supply mechanism and the valve; a heating portion configured to heat the valve; and a failure detector configured to detect a failure of the heating portion. When a failure of the heating portion is detected, the remaining water purging controller performs the remaining water purging process and increases a water discharge power in the remaining water purging process than a water discharge power in the remaining water purging process performed when no failure of the heating portion is detected.

Abstract: When a temperature measured by a temperature measurer is below a specified temperature, a controller of a fuel cell system activates a fuel-gas-concentration increasing mechanism by using electric power of a secondary battery, and executes a fuel-gas-concentration increasing process for increasing the fuel gas concentration toward a first target concentration. When the fuel gas concentration reaches equal to or more than a second target concentration lower than the first target concentration, the controller starts power generation by a fuel cell to activate the fuel-gas-concentration increasing mechanism by using electric power from the fuel cell, and executes the fuel-gas-concentration increasing process until the fuel gas concentration reaches the first target concentration or more.

Abstract: A propeller unit for a marine vessel propulsion device includes an inner cylinder arranged to be fixed to the propeller shaft, an outer cylinder, a first driving force transmitting member, and a second driving force transmitting member. The propeller unit for marine vessel propulsion device further includes a pair of first engaging portions, and a pair of second engaging portions provided on the outer cylinder and the second driving force transmitting member. The pair of second engaging portions are arranged such that the mutual engaging of the respective second engaging portions is disengaged when a driving force is not transmitted to the propeller shaft and are arranged such that the respective second engaging portions become mutually engaged in a driving force transmittable manner by elastic deformation of the first driving force transmitting member when a driving force that is not less than a reference driving force is transmitted to the propeller shaft.

Abstract: A boat propulsion system includes a drive bevel gear fixed on a lower end of a drive shaft, a forwarding bevel gear and a reversing bevel gear rotatably fitted on a propeller shaft and meshing together with the drive bevel gear, and a dog clutch mounted on the propeller shaft and rotatable with the propeller shaft, moves in an axial direction of the propeller shaft, and meshes together with the forwarding bevel gear or the reversing bevel gear to rotate the propeller shaft, in which the propeller shaft comes in contact with the forwarding bevel gear via a forwarding side buffer member having a disc spring as a component member. The boat propulsion system prevents and minimizes sound and impact even when variations in thrust force occur.

Abstract: A propeller unit for a marine vessel propulsion device includes an inner cylinder arranged to be fixed to the propeller shaft, an outer cylinder, a first driving force transmitting member, and a second driving force transmitting member. The propeller unit for marine vessel propulsion device further includes a pair of first engaging portions, and a pair of second engaging portions provided on the outer cylinder and the second driving force transmitting member. The pair of second engaging portions are arranged such that the mutual engaging of the respective second engaging portions is disengaged when a driving force is not transmitted to the propeller shaft and are arranged such that the respective second engaging portions become mutually engaged in a driving force transmittable manner by elastic deformation of the first driving force transmitting member when a driving force that is not less than a reference driving force is transmitted to the propeller shaft.

Abstract: A boat propulsion system includes a drive bevel gear fixed on a lower end of a drive shaft, a forwarding bevel gear and a reversing bevel gear rotatably fitted on a propeller shaft and meshing together with the drive bevel gear, and a dog clutch mounted on the propeller shaft and rotatable with the propeller shaft, moves in an axial direction of the propeller shaft, and meshes together with the forwarding bevel gear or the reversing bevel gear to rotate the propeller shaft, in which the propeller shaft comes in contact with the forwarding bevel gear via a forwarding side buffer member having a disc spring as a component member. The boat propulsion system prevents and minimizes sound and impact even when variations in thrust force occur.

Abstract: A boat has an outboard motor that is mounted to a hull and has a fuel system. The outboard motor has a cowling housing an engine. The fuel system includes a fuel pump disposed within a sealed container. The sealed container provides a physical and thermal barrier to seawater and engine heat that may otherwise degrade fuel pump operation. The sealed container can also include an internal insulator.

Abstract: A boat has an outboard motor that is mounted to a hull and has a fuel system. The outboard motor has a cowling housing an engine. The fuel system includes an insulator that covers at least a portion of a fuel filter. The insulator provides a physical and thermal barrier to seawater and engine heat that may otherwise cause vaporization of the fuel. The insulator may include one or more insulating pieces.

Abstract: A boat has an outboard motor that is mounted to a hull and has a fuel system. The outboard motor has a cowling housing an engine. The fuel system includes a fuel pump disposed within a sealed container. The sealed container provides a physical and thermal barrier to seawater and engine heat that may otherwise degrade fuel pump operation. The sealed container can also include an internal insulator.

Abstract: An outboard motor includes a housing unit mounted on an associated watercraft. An engine is disposed above the housing unit. The engine defines a first exhaust passage communicating with a combustion chamber of the engine. The housing unit defines a second exhaust passage communicating with the first exhaust passage. The second exhaust passage communicates with outside through at least an underwater exhaust discharge port formed at a portion of the housing unit. An air intake device communicates with either the first exhaust passage or the second exhaust passage. The air intake device includes a one-way valve that allows air to enter the first or second exhaust passage and inhibits exhaust gases from moving beyond the one-way valve.

Abstract: An outboard motor includes a housing unit mounted on an associated watercraft. An engine is disposed above the housing unit. The engine defines a first exhaust passage communicating with a combustion chamber of the engine. The housing unit defines a second exhaust passage communicating with the first exhaust passage. The second exhaust passage communicates with outside through at least an underwater exhaust discharge port formed at a portion of the housing unit. An air intake device communicates with either the first exhaust passage or the second exhaust passage. The air intake device includes a one-way valve that allows air to enter the first or second exhaust passage and inhibits exhaust gases from moving beyond the one-way valve.

Abstract: An engine includes an engine body and an air induction system. The engine body has a cylinder block that defines cylinder bores. Pistons are reciprocally disposed within the respective cylinder bores. A cylinder head member closes the respective cylinder bore to define combustion chambers together with the cylinder bores and the pistons. The air induction system is arranged to supply air to the combustion chambers. The air induction system includes intake conduits that communicate with the combustion chambers. Inlet conduits communicate with the intake conduits and extend along the intake conduits to provide a sufficiently long air intake to improve the torque characteristics of the engine. In one preferred outboard marine embodiment, this longer air intake does not require any increase in the size of the engine cowling.

Abstract: An outboard motor includes an improved arrangement for an exhaust system, in association with a lubricant tank and a cooling system, for a four-cycle internal combustion engine that powers the outboard motor. The cooling system discharges coolant independent of an exhaust pipe and an expansion chamber of the exhaust system so as to inhibit an influx of coolant into the engine should the engine become temporarily disabled. In addition, the cooling system provides a pool or bath of coolant between the exhaust pipe and the lubricant tank to inhibit excessive heating of these components during normal and abnormal running conditions (i.e., if the engine becomes disabled).