Gas sensor with sensitive element enclosed in perforated hood

摘要

A gas sensor, e.g. oxygen sensor of the solid electrolyte concentration cell type, having a gas-sensitive element comprising a plate-shaped substrate fixed to an end portion of the sensor body and a laminate of relatively thin layers. A hollow cylindrical protective hood is attached to the sensor body to enclose the sensitive element therein, and two or more openings are formed in the cylindrical wall of the hood to allow a gas subject to measurement to flow into the interior of the hood and flow out. To avoid direct exposure of the sensitive element, which exhibits directionality in its output characteristics with regard to the gas flow through said openings, each of said openings is located between the sensitive element and the free end of the hood such that a cross-sectional plane intersecting the openings does not intersect the sensitive element.