Abstract: In automatically stopping and restarting an engine on the basis of the operating conditions of various parts in a vehicle, the automatic engine stop and restart are effected by cutting off a fuel system, but not cutting off an iginition system. More specifically, a fuel control valve is provided in a path for feeding fuel to a slow port, and this control valve is closed on condition that at least the vehicle speed is in the state of zero and other conditions of allowing the automatic engine stop and restart are not met. An ignition signal taken from the energized ignition system is used to ensure that the engine is not started when it is already running.

Abstract: Determination as to whether the condition of automatically stopping an engine is formed or not is made based on outputs from pluralities of sensors and switches for detecting the operating conditions of various portions of a vehicle. Even if the result of determination satisfies the conditions of automatic stop, automatic stop is not effected when the temperature of the engine cooling water exceeds predetermined temperature limits.

Abstract: An oxygen sensor for measuring the existence of oxygen in gases in an exhaust system or the like. An electrolytic body is formed as a tube with an open end and a closed end. An internal electrode is coated on the interior surface of the electrolytic body, and an external electrode is coated on the exterior surface of the electrolytic body. The external electrode is exposed to the gases. A tubular housing is airtightly connected around the outer circumference of the open end of the tubular electrolytic body, thus defining within it an internal space to which the internal electrode is exposed. An electrically conducting tube, coaxial with the tubular housing, is electrically connected to the internal electrode by its end closest thereto. Atmospheric air can only pass into the space within the tubular housing through a side hole in the housing which opposes a side hole in the electrically conducting tube.

Abstract: An oxygen sensor to be used with internal combustion engines, in automobiles, etc.. The sensor includes a solid electrolyte tube with a closed tip, an outer and an inner electrode respectively formed on the outside and the inside of the electrolyte tube, a housing to hold the tube, electrically conductive means to take out the electrical output of the inner metal electrode, a cover supported by the housing; an air passage in an end opening of the cover; and a multi-layer heat-resistant filter with a low rate of thermal expansion in the air passage.