Oxygen concentration sensor for an internal combustion engine

摘要

An oxygen concentration sensor having an oxygen ion conductive solid electrolyte member forming a gas diffusion restricted region into which a measuring gas is introduced, includes a pump current source for supplying a pump current across a pair of electrodes sandwiching the solid electrolyte through a current detection element and a heater for heating the solid electrolyte. By an arrangement in which the current detection element is connected to one of the pair of electrodes facing the gas diffusion restricted region, error of measurement due to leakage of a drive current of the heater is prevented.