DIAGNOSIS METHOD AND DIAGNOSIS APPARATUS FOR ELECTROCHEMICAL TYPE SENSOR

摘要

PROBLEM TO BE SOLVED: To establish a diagnosis method for an electrochemical type sensor capable of rationally estimating a factor other than abnormality related to a humid condition between a detection electrode and a counter electrode and abnormality due to jamming of a part of or the whole diffusion limitation hole.SOLUTION: The AC of an interface abnormality diagnosis frequency is applied between a detection electrode and a counter electrode, and the capacity component of impedance between the detection electrode and the counter electrode is detected. When the capacity component of the detected impedance increases more than the capacity component of reference impedance in a normal state, it is diagnosed that an electrode catalyst forming the detection electrode or the counter electrode is possibly in an abnormal state due to the influence of the electrolyte of an electrolyte layer.