Toyota Jidosha Kabushiki Kaisha

Takeho Aisaka

Hiroyuki Imanishi

Takashi Nakamura

Takuya Matsumoto

Shuya Kawahara

Hiroshi Sawada

Yasushi Iwazaki

Shigeki Hasegawa

Yusuke Kawamura

Yoshikatsu Fujimura

Shun Matsumoto

Makoto Sato

Provided is a fuel cell system capable of suppressing the movement of an operating point of a compressor between a surge region and a non-surge region to reduce operation sounds and vibrations, the fuel cell system including at least: a fuel cell; a compressor; a dry state estimation part to estimate a dry state of the fuel cell; and a pressure target control part to control a pressure target, wherein the pressure target control part is capable of executing at least rise control and lower control, the rise control and the lower control being such that an operating point of the compressor is positioned outside a surge region, a current pressure target is corrected to the value same as a last pressure target if the current pressure target is lower (higher) than the last pressure target when the rise control (lower control) is being carried out.

Fuel cell system

A fuel cell system including a fuel cell, an air compressor that supplies oxidant gas to the fuel cell, an upstream supply pipe provided with the air compressor, a downstream supply pipe connected to the upstream supply pipe and the fuel cell, an upstream discharge pipe connected to the fuel cell, a downstream discharge pipe connected to the upstream discharge pipe, a bypass pipe, a valve mechanism configured to be switchable between a supply state and a bypass state, and a controller configured to control the air compressor, the valve mechanism, and a power generation state of the fuel cell.

An electronic control device calculates the maximum actual oxygen storage capacity of a catalyst. The gradient of a linear expression formed between the catalyst temperature and the maximum oxygen storage capacity of the catalyst is stored for each degradation level of the catalyst. The gradient can be learned in accordance with the same temperature of the catalyst and the maximum actual oxygen storage capacity. When the maximum actual oxygen storage capacity is calculated, it is revised in accordance with the temperature of the catalyst, a reference temperature, the linear expression, and the learned gradient. The revised maximum oxygen storage capacity which is the maximum oxygen storage capacity when the temperature of the catalyst during the same calculation period is equal to the reference temperature is then calculated. If a response delay is detected in the output of an oxygen sensor, the gradient of the learned linear expression is discarded.

Device for purifying exhaust gas of internal combustion engine

A determination oxygen storage amount used to determine whether a catalyst is degraded is a value obtained by applying a correction amount for removing error caused by response delay time of an output signal of an oxygen sensor to an oxygen storage amount calculated every short time. The correction amount is a value that is calculated using slopes stored in memory, i.e., the slopes for the number of storage cycles (&#x3e;the short time) corresponding to the response delay time, or the like, and becomes more accurate as a value corresponding to the error as the storage cycle becomes relatively shorter with respect to the response delay time and the number of the slopes stored in the memory increases. The necessary storage capacity of the memory is inhibited from increasing excessively even if the number of the slopes stored in the memory is large.

Catalyst degradation detection apparatus and catalyst degradation detection method

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Toyota, Japan

Takeho Aisaka