Parkhurst & Wendel, L.L.P.
Gas sensor
 Disclosed is a gas sensor comprising a first internal space for making communication with the external space via a first diffusion rate-determining section, a first electrochemical pumping cell for controlling the oxygen concentration in the atmosphere in the first internal space to have a predetermined value, a second internal space for making communication with the first internal space via a second diffusion rate-determining section, a second electrochemical pumping cell for finely adjusting the oxygen concentration in the atmosphere in the second internal space to have a predetermined value, a third internal space for making communication with the second internal space via a third diffusion rate-determining section, a third electrochemical pumping cell for pumping out oxygen produced by reduction or decomposition of a component having bound oxygen in the measurement gas in the third internal space, and an ammeter Ip for detecting a pumping current which is allowed to flow in accordance with the pumping operation effected by the third electrochemical pumping cell. Accordingly, it is possible to avoid interference exerted on the sensitivity for NO by the change in oxygen concentration in exhaust gas, and improve the measurement accuracy for the measurement gas component. 
NGK Insulators, Ltd.
G
G01N
inventional
Kunihiko Nobuhide
Nakagaki Kato