Abstract: A head includes a face portion, a sole portion, and an internal weight portion provided on an inner surface of the sole portion and located apart from the face portion. The internal weight portion includes a base portion, and a protruding portion protruding from the base portion toward a face side and located apart from the inner surface of the sole portion. The protruding portion is positioned on the face side with respect to the head center of gravity. A thickness of a toe-side part of the protruding portion and/or a thickness of a heel-side part of the protruding portion is greater than a thickness of a middle part of the protruding portion. Alternatively, a middle part of the protruding portion in a toe-heel direction is absent. The internal weight portion may be formed integrally with the sole portion, or may be a different member from the sole portion.

Abstract: A gas sensor and method of producing the same, the gas sensor including a sensor element extending along a longitudinal axis of the gas sensor; a metal shell surrounding the sensor element; and a protector fixed on a front portion of the metal shell and covering a front portion of the sensor element which projects from the front end of the metal shell, wherein an oil agent is present on one or both of an inner gas-receiving surface of the metal shell and an inner peripheral surface of the protector in a total amount of less than 0.7 mg.

Abstract: A gas sensor and method of producing the same, the gas sensor including a sensor element extending along a longitudinal axis of the gas sensor; a metal shell surrounding the sensor element; and a protector fixed on a front portion of the metal shell and covering a front portion of the sensor element which projects from the front end of the metal shell, wherein an oil agent is present on one or both of an inner gas-receiving surface of the metal shell and an inner peripheral surface of the protector in a total amount of less than 0.7 mg.

Abstract: A gas sensor (1) comprises: a pair of porous electrode layers (2b and 2c); a detector element (2) between the porous electrode layers (2b and 2c), wherein the detecting element (2) comprises an oxygen ion conductive solid electrolyte comprising zirconium oxide as a major component, and one of the porous electrode layers is a detecting-side electrode (2b) to be exposed to a gas to be measured; and a ceramic protecting layer (2p) covering the surface of the detecting-side electrode (2b), wherein the ceramic protecting layer (2p) comprises a magnesia.alumina spinel component, an excess magnesium oxide component not involved in the magnesia.alumina spinel component, and a zirconium oxide component.

Abstract: There is disclosed an oxygen sensor disposed before an exhaust gas purifying catalyst of an engine which uses a hydrocarbon containing fuel with a H/C ratio of three or more. An oxygen sensor 1 is provided with a solid electrolytic body 2 which can generate a difference in oxygen concentration with reference gas and measured gas, a reference electrode 3 and a detection electrode 4 formed on inner and outer surfaces of the solid electrolytic body 2, and a porous protective layer 5 for covering the detection electrode 4. The detection electrode 4 is formed only of a metal like Pt which promotes oxidizing reaction of methane to have a thickness of 1 to 2 &mgr;m. In the protective layer 5, only a second protective layer 5b carries Pt catalyst 6 which promotes oxidizing reaction of hydrogen, and the amount of carried catalyst is in the range of 0.5 to 7 mol % relative to the whole of the second protective layer 5b.

Abstract: An oxygen sensor is disposed behind an exhaust gas purifying catalyst for an internal combustion engine and which suppresses the influence of unburnt hydrocarbon on the output voltage. A sensor element 1 is provided with a detection electrode 4 on the outer face of a zirconia ceramic body 2, a reference electrode 3 on the inner face of the ceramic body 2 and a spinel protective layer 5 on the outer surface of the detection electrode 4. The tip end of the sensor element 1 is covered with a protective cover 10 which is provided with an outer partition wall 11 having through holes 11a and an inner partition wall 12 having through holes 12a. In a case where the pressure difference between the inside and outside of the protective cover 10 is &Dgr;P(atm) when the atmospheric air with a volume flow rate Q(L/min) is passed into the protective cover 10 from the outside, the ratio &Dgr;P/Q2 is 3.2×10−5 (atm·min2·L−2).

Abstract: Disclosed is a process for the formation of an electrode for sensor element which comprises the formation of a platinum electrode on a solid electrolyte formed in a predetermined shape as a sensor element by electroless plating, wherein said electroless plating is effected in a platinum (II) complex solution as a plating solution on which a reducing agent for reducing said platinum (II) complex is acted.

Abstract: An oxygen sensor including, at least, a) an oxygen pump element having a solid electrolyte plate and two porous electrodes, one on each surface of the solid electrolyte plate, b) a gas diffusion chamber facing one of the porous electrodes, and c) a gas diffusion path connecting the gas diffusion chamber and the ambience of the oxygen sensor, is defined its thickness between 0.7 to 1.25 mm, and its width between 2.8 to 4.0 mm. The restricted size renders higher resistance against repeated thermal shocks, and shorter warming-up time, which leads to greater accuracy and higher responsiveness in the oxygen content measurement.

Abstract: A control system has a controlled element, such as an element for sensing an air/fuel ratio of an internal combustion engine, having a high order lag, a controller element connected with the controlled element to form a closed path, and a third element connected with the controlled element and controller element for modifying an output signal of the controlled element in accordance with an output signal of the controller element so that a phase angle in a frequency response of a loop transfer function of the controlled and controller elements does not reach -180.degree..

Abstract: An apparatus for evaluating an oxygen sensor includes a device for mixing a fuel and an oxygen-containing gas in an appropriate ratio to prepare a fuel mixture. A burner is connected to the mixing device for burning the fuel mixture to produce a gaseous combustion product. A tubular member extends from the burner for supplying the combustion product. A nozzle is connected to the tubular member for introducing a fuel and an oxygen-containing gas into the tubular member so that the combustion product is of a desired excess air ratio (air-fuel ratio) and a mounting device for the sensor to be evaluated is disposed on the tubular member, downstream of the nozzle.