Patent ID: 6432289
Filing Date: 2002-08-13
Classification: G01N

Abstract:
An oxygen concentration detector comprising:a) an oxygen concentration sensing element comprised of a solid electrolyte and an outer electrode provided on the external surface of said solid electrolyte for contributing to detecting the concentration of oxygen in a gas to be measured; b) a heater disposed near said solid electrolyte for heating said solid electrolyte said outer electrode being located within the range defined by the length of the heat-generating part of said heater, in the direction of the length of said sensing element; and c) a protecting cover separated from said sensing element and extending to cover its exterior for protecting said sensing element, said protecting cover having a first level and a second level of multiple openings in the lengthwise direction, said first and second levels of multiple openings being located outside of the range corresponding to said outer electrode in the direction of the length of said sensing element, there being no openings in said protecting cover in the range corresponding to said outer electrode, said first level of openings being openings which are nearest to an end of said outer electrode and said second level of openings being openings which are nearest to the opposite end of said outer electrode; wherein the relationship between the length L1 of said heat-generating part and the distance L2, in the direction of the length of said sensing element, between the edge, on the side of the openings of the second level, of the openings of said first level and the edge, on the side of the openings of the first levels of the openings of the second level, is such that 0.9&lE;L1/L2&lE;1.3 is satisfied.