Oxygen-sensing element
 An oxygen-sensing element particularly for use in the exhaust stream of an internal combustion engine. In one embodiment, the sensing element may be a tubular solid electrolyte body with a transverse web forming a relatively shallow recess at one end of the body and a relatively deep tube at the other. Separate electrodes are formed on the surface of the body proximate the recess and on both opposing sides of the web. A porous plug disposed in the recess covers one of the electrodes. When the electrode on the surface of the body is exposed to the exhaust stream of a fuel-rich aur-fuel mixture, the EMF across that electrode and the electrode on the underside of the web, which is exposed to fresh air, is indicative of the oxygen content of the exhaust stream. When an exhaust stream from a fuel-lean air-fuel mixture is present, the magnitude of an oxygen pumping current that flows between the electrodes disposed on opposing sides of the web, in response to a voltage applied across those electrodes, indicates the oxygen content of the exhaust stream. 
Stemcor Corporation
G
G01N
inventional
Hisao
Yamada