An apparatus for detecting the deterioration of a three-way catalytic converter for an internal combustion engine

摘要

The object of the present invention is to provide an apparatus for detecting the deterioration of a three-way catalytic converter which can accurately detect the deterioration degree. The present apparatus is furnished with an upstream A/F sensor installed at the upstream side of the converter and a downstream A/F sensor installed at the downstream side of the converter. The output of the upstream sensor is converted into the converted output for calculating the trajectory length. The trajectory length of the converted output and that of the output of the downstream sensor are respectively calculated, and the deterioration degree of the converter is detected based on these two trajectory lengths to avoid the misjudgment. The detecting accuracy can be better improved by compensating for the aberration of the balance between the oxygen absorbing power and the oxygen releasing power of the converter.