Multilayered gas sensing element employable in an exhaust system of an internal combustion engine

摘要

An objective gas to be measured is introduced into first and second chambers which are connected via a diffusion resistive passage. A first electrochemical cell is provided in the first chamber for pumping in and out oxygen in accordance with an applied voltage. A second electrochemical cell is provided in the second chamber and responsive to application of a predetermined voltage for generating a sensor current representing a specific gas concentration in the objective gas. The first electrochemical cell is located between the first chamber and a reference gas chamber so that oxygen pumping in and out operation can be performed between the first chamber and the reference gas chamber.