Oxygen sensor with the heater element contacting the inner surface of the closed end tubular solid electrolyte

摘要

A solid electrolytic body (10) has an inside space serving as a reference gas chamber (18). A sensing electrode (11) and a reference electrode (12) are formed on the surface of the solid electrolytic body (10). A heater (19) is disposed in the reference gas chamber (18). A contact portion (100) comprises a region where the heater (19) is brought into contact with the inner surface (102) of the solid electrolytic body (10) and an opposing region on the outer surface (101) of the solid electrolytic body (10). The sensing electrode (11) includes at least part of the contact portion (100). A gas receiving surface region (13), exposed to the measuring gas, extends from an element tip (14) to a position spaced by a distance L away from the element tip (14). At least part of the contact portion (100) is located in a region extending from the element tip (14) to a position spaced by a distance 0.4L away from the element tip (14). The sensing electrode (11) is entirely located in a region extending from the element tip (14) to a position spaced by a distance 0.8L away from the element tip (14).