Nissan Motor Company Limited

Tadashi Matoba

Takeaki Obata

Shigeru Kamegaya

Mitsutaka Abe

Akihiro Iiyama

Koichi Yamaguchi

Tadashi Shoji

Teruyuki Itoh

Akihiko Kakuhou

A fuel cell system and related method are disclosed having a catalytic combustorcombusting mixed gas between fuel gas, or anode off-gas, and oxidant gas or cathode off-gas, and a system controlleroperative 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.

Fuel cell system and fuel cell operating method

A fuel cell system and related method are disclosed having a system controllerthat executes enthalpy calculation based on status signals, related to anode off-gas and cathode off-gas, detected by a temperature detector, a pressure detectorand a humidity detectorfor thereby predicting a combustion temperature of a combustorduring 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 combustorto a value below the upper limit value.

Fuel cell system and related method

A fuel cell system is provided with a humidifying device () for humidifying at least one of fuel gas and oxygen-bearing gas, a water passage () through which water from a water tank () flows, a water removing device () for supplying purge gas to the water passage in order to remove the water in the water passage, and a water recirculating device () for enabling water to flow through the water passage. The fuel cell system is also provided with a shutoff valve () for blocking the water passage such that water from the water tank does not flow into the water recirculating device, the shutoff valve () being provided between the water tank () and the water recirculating device (). When a shutdown operation of the fuel cell system begins, a controller () controls the shutoff valve () to open and controls the water removing device () such that purge gas is supplied to the water passage. The controller () also controls the shutoff valve () to block the water passage after the water has been expelled from the water passage.

Fuel cell system

When a system starts, a fuel-air mixture (rich air-fuel ratio) of fuel and air supplied to a start-up combustor () is ignited by a glow plug (), 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 ().

Fuel cell drive system

In a fuel cell system, a start-up combustor () combusts a gaseous mixture of fuel supplied by an injector () and air supplied from a valve (C) at a rich air-fuel ratio, and supplies high temperature combustion gas to a reformer () in order to activate the reforming catalyst. After completion of activation, the controller () stops supply of air by the valve (C) and thereafter stops the fuel supply by the injector (). 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 (). 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.

Control of start-up combustor for fuel cell power plant

A fuel injector () supplies liquid fuel to a catalytic combustor () 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 (Qf) during a predetermined time (t) after starting fuel injection. After the predetermined time, the injection amount (Qf) is set to a second injection amount (Qf) which is larger than the first injection amount (Qf). When the elapsed time after starting fuel injection is smaller than a value (t), the discharged amount of uncombusted fuel is reduced by setting the injection amount (Qf) to a minimum injection amount (Qf) which allows ignition and combustion in the catalyst.

Control for catalytic combustor

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..

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Yokohama, Japan

Tadashi Matoba