Abstract: A method of estimating an ideal air-fuel ratio in an internal combustion engine, comprises receiving an output of an upstream air-fuel ratio sensor and an output of a downstream air-fuel ratio sensor, the upstream air-fuel ratio sensor being attached to an exhaust gas passage such that it is positioned upstream of a catalyst provided in the exhaust gas passage to purify an exhaust gas, the downstream air-fuel ratio sensor being attached to the exhaust gas passage such that it is positioned downstream of the catalyst; detecting a state in which the catalyst does not store or release oxygen based on the output of the downstream air-fuel ratio sensor; and deciding as an estimated ideal air-fuel ratio in the internal combustion engine an air-fuel ratio detected by the upstream air-fuel ratio sensor when the state in which the catalyst does not store or release oxygen is detected.

Abstract: A method of estimating an ideal air-fuel ratio in an internal combustion engine, comprises receiving an output of an upstream air-fuel ratio sensor and an output of a downstream air-fuel ratio sensor, the upstream air-fuel ratio sensor being attached to an exhaust gas passage such that it is positioned upstream of a catalyst provided in the exhaust gas passage to purify an exhaust gas, the downstream air-fuel ratio sensor being attached to the exhaust gas passage such that it is positioned downstream of the catalyst; detecting a state in which the catalyst does not store or release oxygen based on the output of the downstream air-fuel ratio sensor; and deciding as an estimated ideal air-fuel ratio in the internal combustion engine an air-fuel ratio detected by the upstream air-fuel ratio sensor when the state in which the catalyst does not store or release oxygen is detected.

Abstract: A vehicle including an engine, a tilting sensor configured to detect that a vehicle body of the vehicle has been tilted a predetermined angle or larger, a driving state sensor configured to detect a driving state of the vehicle using a component other than the tilting sensor, and a determiner configured to determine whether or not to stop the engine, based on a signal received from the tilting sensor, and a signal received from the driving state sensor.

Abstract: A wind turbine-driven hydrogen production system controlling a power converter system such that the wind turbine stays in its operable range for a longer time and thus the hydrogen production system produces hydrogen for a longer time. The wind turbine-driven hydrogen production system varies an amount of electrical current supplied to an electrolytic hydrogen production system according to the rotational speed of the wind turbine to reduce variations in the rotational speed. Furthermore, the pitch angle of the wind turbine varies according to the speed. Thus, variations in the speed of the wind turbine can be reduced. A permanent-magnet generator is used as the electricity generator of the wind turbine to obtain a power supply at start-up. Alternatively, a power storage system used as assistive equipment at start-up is supplementarily added or only a power supply for the controllers is supplied from a system.

Abstract: A vehicle including an engine, a tilting sensor configured to detect that a vehicle body of the vehicle has been tilted a predetermined angle or larger, a driving state sensor configured to detect a driving state of the vehicle using a component other than the tilting sensor, and a determiner configured to determine whether or not to stop the engine, based on a signal received from the tilting sensor, and a signal received from the driving state sensor.

Abstract: A wind turbine-driven hydrogen production system controlling a power converter system such that the wind turbine stays in its operable range for a longer time and thus the hydrogen production system produces hydrogen for a longer time. The wind turbine-driven hydrogen production system varies an amount of electrical current supplied to an electrolytic hydrogen production system according to the rotational speed of the wind turbine to reduce variations in the rotational speed. Furthermore, the pitch angle of the wind turbine varies according to the speed. Thus, variations in the speed of the wind turbine can be reduced. A permanent-magnet generator is used as the electricity generator of the wind turbine to obtain a power supply at start-up. Alternatively, a power storage system used as assistive equipment at start-up is supplementarily added or only a power supply for the controllers is supplied from a system.

Abstract: When a welded joint is produced for joining metal components by applying a plurality of layers of deposited metal, the plurality of layers of deposited metal are provided in a groove of a weld preparation formed between the metal components to be joined in such a manner that each layer of deposited metal has a small thickness and a large width crosswise of the groove and the layers are arranged to be superposed one over another. During this process, a coarse metal structure formed when each underlying layer of deposited metal is provided is completely tempered and transformed into a fine metal structure by the heat generated when each overlying layer of deposited metal is provided. Thus the welded joint produced by this method shows an excellent performance in service.