| 摘要 |
PURPOSE:To make it possible to accurately detect an air-fuel ratio, by providing a solid electrolyte oxygen concn. cell element, a solid electrolyte oxygen pump element and an oxygen reference element wherein a metal oxide semiconductor is provided to the surface of an electric insulating member. CONSTITUTION:The oxygen reference element 17 of an air-fuel ratio detection part 2 is constituted of a highly heat conductive electric insulating plate shaped member 18 having an opening part (f) provided thereto so as not to inhibit the flowing of exhaust gas and a metal oxide semiconductor 19. In addition, in order to arrange the oxygen reference element 17 in an exhaust pipe 1, for example, a heat resistant spacer 22 is arranged so as to provide a gap (h) to the surface of an oxygen concn. cell element 10 in the side opposite to the side of the small gap (g) of said cell element 10 to fix the oxygen reference element 17. The oxygen pump element 10, the highly heat conductive electric insulating member 18 and the oxygen reference element 17 are superposed through the small gap (g) and the gap (h) and fixed at base parts thereof by heat resistant ceramic adhesives 21, 22. By this mechanism, an air-fuel ratio can be measured accurately. |
