System for detecting deterioration of a three-way catalyst of an internal combustion engine

摘要

A system for detecting deterioration of a three-way catalyst of an internal combustion engine comprises first and second HC sensors, and a central processing unit (CPU). The first and second HC sensors are arranged in the exhaust passage of the engine at locations upstream and downstream of the three-way catalyst, respectively, for detecting concentration of hydrocarbons present in exhaust gases. The central processing unit (CPU) is operable to compare an output from the first HC sensor with an output from the second HC sensor, and determine from results of the comparison whether the three-way catalyst is deteriorated.