METAL OXIDE OXYGEN SENSOR BASED ON PHASE TRANSITION AND DETECTION OF OXYGEN PARTIAL PRESSURE CHANGE

摘要

PROBLEM TO BE SOLVED: To provide an oxygen sensor having excellent sensitivity and an excellent reaction time in various air/fuel ratios. ;SOLUTION: A sensor 10 contains a detection substance 12 selected from a metal or metal oxide changeable between the certain phase A and separate phase B of the metal or metal oxide when exposed to gas containing oxygen changed in its partial pressure at high temp. Accompanied by this phase change, measurable physical characteristics change. This sensor 10 contains a heating means 19 capable of keeping the temp. gradient traversing the detection substance so that the detection substance is present in at least two phases prescribing the boundary line 22 almost vertical to the long axis of the temp. gradient and longitudinally moving along the long axis corresponding to a change in the oxygen partial pressure in an atmosphere during active detection operation and connectable to a power supply. This sensor 10 further contains a means generating output signal corresponding to the movement of the boundary line exceeding the detection position where the detection substance is fixed.;COPYRIGHT: (C)1999,JPO