Abstract: A fuel cell system and related method are disclosed having a catalytic combustor 7 combusting mixed gas between fuel gas, or anode off-gas, and oxidant gas or cathode off-gas, and a system controller 35 operative to perform control such that during at least an ignition period until the catalytic combustor is discriminated to be sufficiently activated from commencement of supplying the mixed gas to the catalytic combustor, a fuel gas concentration of the mixed gas is maintained in a given range (greater than a catalyst activation lower limit and less than flammable lean-limit) whereas after the ignition period has been elapsed, the mixed gas is supplied to the catalytic combustor even if the fuel gas concentration lying at a value deviated from the given range.

Abstract: A fuel cell system and related method are disclosed having a system controller 37 that executes enthalpy calculation based on status signals, related to anode off-gas and cathode off-gas, detected by a temperature detector 29, a pressure detector 30 and a humidity detector 31 for thereby predicting a combustion temperature of a combustor 7 during purging. In the presence of a predicted combustion temperature exceeding an upper limit, cathode off-gas is increased in volume to limit a combustion temperature of the combustor 7 to a value below the upper limit value.

Abstract: A fuel cell system is provided with a humidifying device (27, 28) for humidifying at least one of fuel gas and oxygen-bearing gas, a water passage (11) through which water from a water tank (5) flows, a water removing device (2, 3, 3a, 4) for supplying purge gas to the water passage in order to remove the water in the water passage, and a water recirculating device (8) for enabling water to flow through the water passage. The fuel cell system is also provided with a shutoff valve (7) for blocking the water passage such that water from the water tank does not flow into the water recirculating device, the shutoff valve (7) being provided between the water tank (5) and the water recirculating device (8). When a shutdown operation of the fuel cell system begins, a controller (48) controls the shutoff valve (7) to open and controls the water removing device (2, 3, 3a, 4) such that purge gas is supplied to the water passage.

Abstract: When a system starts, a fuel-air mixture (rich air-fuel ratio) of fuel and air supplied to a start-up combustor (20) is ignited by a glow plug (40), and high temperature gas containing fuel components for a reforming reaction are generated. The high temperature gas containing fuel components for the reforming reaction is supplied to a reformer (22).

Abstract: An on-vehicle fuel cell system of the present invention has: a fuel cell stack which is mounted on a vehicle and generates power by using fuel gas and oxidant gas, the fuel cell stack including a water passage which performs cooling and humidification in an inside thereof; a water circulator which circulates water through the water passage; a water tank which reserves the water; a discharge device which discharges extra water from the water tank to an outside of the vehicle; and a discharge control device which controls the discharge of the water by the discharge device. The discharge control device makes a control not to discharge liquid-water to the outside of the vehicle in a case where a road surface condition immediately under the vehicle is estimated to be a predetermined road surface condition.

Abstract: A fuel cell system and related method are disclosed having a catalytic combustor 7 combusting mixed gas between fuel gas, or anode off-gas, and oxidant gas or cathode off-gas, and a system controller 35 operative to perform control such that during at least an ignition period until the catalytic combustor is discriminated to be sufficiently activated from commencement of supplying the mixed gas to the catalytic combustor, a fuel gas concentration of the mixed gas is maintained in a given range (greater than a catalyst activation lower limit and less than flammable lean-limit) whereas after the ignition period has been elapsed, the mixed gas is supplied to the catalytic combustor even if the fuel gas concentration lying at a value deviated from the given range.

Abstract: In a fuel cell system, a start-up combustor (10) combusts a gaseous mixture of fuel supplied by an injector (15) and air supplied from a valve (12C) at a rich air-fuel ratio, and supplies high temperature combustion gas to a reformer (3) in order to activate the reforming catalyst. After completion of activation, the controller (50) stops supply of air by the valve (12C) and thereafter stops the fuel supply by the injector (15). During this delay period, combustion of fuel using residual air is performed at a rich air-fuel ratio by increasing the fuel supply amount of the injector (15). Thus it is possible to prevent temperature increase of the combustion gas as a result of the gaseous mixture approaching a stoichiometric air-fuel ratio after stopping fuel supply.

Abstract: A fuel injector (11) supplies liquid fuel to a catalytic combustor (9) of a fuel reforming device during startup of a fuel reforming device. A controller sets the injection amount (Qf) for liquid fuel to a first injection amount (Qf1) during a predetermined time (t1) after starting fuel injection. After the predetermined time, the injection amount (Qf) is set to a second injection amount (Qf2) which is larger than the first injection amount (Qf1). When the elapsed time after starting fuel injection is smaller than a value (t1), the discharged amount of uncombusted fuel is reduced by setting the injection amount (Qf) to a minimum injection amount (Qf1) which allows ignition and combustion in the catalyst.

Abstract: A fuel cell system and related method are disclosed having a system controller 37 that executes enthalpy calculation based on status signals, related to anode off-gas and cathode off-gas, detected by a temperature detector 29, a pressure detector 30 and a humidity detector 31 for thereby predicting a combustion temperature of a combustor 7 during purging. In the presence of a predicted combustion temperature exceeding an upper limit, cathode off-gas is increased in volume to limit a combustion temperature of the combustor 7 to a value below the upper limit value.

Abstract: A fuel injector (11) supplies liquid fuel to a catalytic combustor (9) of a fuel reforming device during startup of a fuel reforming device. A controller sets the injection amount (Qf) for liquid fuel to a first injection amount (Qf1) during a predetermined time (t1) after starting fuel injection. After the predetermined time, the injection amount (Qf) is set to a second injection amount (Qf2) which is larger than the first injection amount (Qf1). When the elapsed time after starting fuel injection is smaller than a value (t1), the discharged amount of uncombusted fuel is reduced by setting the injection amount (Qf) to a minimum injection amount (Qf1) which allows ignition and combustion in the catalyst.

Abstract: A fuel cell system is provided with a humidifying device (27, 28) for humidifying at least one of fuel gas and oxygen-bearing gas, a water passage (11) through which water from a water tank (5) flows, a water removing device (2, 3, 3a, 4) for supplying purge gas to the water passage in order to remove the water in the water passage, and a water recirculating device (8) for enabling water to flow through the water passage. The fuel cell system is also provided with a shutoff valve (7) for blocking the water passage such that water from the water tank does not flow into the water recirculating device, the shutoff valve (7) being provided between the water tank (5) and the water recirculating device (8). When a shutdown operation of the fuel cell system begins, a controller (48) controls the shutoff valve (7) to open and controls the water removing device (2, 3, 3a, 4) such that purge gas is supplied to the water passage.

Abstract: When a system starts, a fuel-air mixture (rich air-fuel ratio) of fuel and air supplied to a start-up combustor (20) is ignited by a glow plug (40), and high temperature gas containing fuel components for a reforming reaction are generated. The high temperature gas containing fuel components for the reforming reaction is supplied to a reformer (22).

Abstract: In a fuel cell system, a start-up combustor (10) combusts a gaseous mixture of fuel supplied by an injector (15) and air supplied from a valve (12C) at a rich air-fuel ratio, and supplies high temperature combustion gas to a reformer (3) in order to activate the reforming catalyst. After completion of activation, the controller (50) stops supply of air by the valve (12C) and thereafter stops the fuel supply by the injector (15). During this delay period, combustion of fuel using residual air is performed at a rich air-fuel ratio by increasing the fuel supply amount of the injector (15). Thus it is possible to prevent temperature increase of the combustion gas as a result of the gaseous mixture approaching a stoichiometric air-fuel ratio after stopping fuel supply.

Abstract: A direct-injection type spark-ignition internal combustion engine comprises a fuel-injection valve whose spray hole is inclined toward a piston crown, while an uppermost line of fuel spray injected through the spray hole is set at a lower level than electrodes of the spark plug and a lowermost line of the fuel spray is in spaced relationship with a cylinder inner wall close to the spray hole. The piston crown is formed with a recessed portion and a raised flat-surface portion to define a ridge line as an intersecting line between them. The ridge line is offset from a center axis of the cylinder by a predetermined distance toward the exhaust-valve port side. Preferably, a spray angle between the uppermost and lowermost lines is set within a predetermined angle range of 70.degree..+-.20.degree..