DIAGNOSTIC DEVICE AND CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide a diagnostic device for an internal combustion engine for separating and detecting degradation in responsiveness and degradation in gain of a linear air fuel ratio sensor, and thereby to prevent degradation in exhaust gas and wrong diagnoses when the sensor is abnormal. SOLUTION: The diagnostic device for the internal combustion engine is installed upstream of a catalyst of the internal combustion engine to determine an abnormality of the linear air fuel ratio sensor linearly detecting an air fuel ratio of exhaust gas. The diagnostic device for the internal combustion engine is provided with a responsiveness degradation/gain degradation detection means for separating and detecting responsiveness degradation in which responsiveness of the linear air fuel ratio sensor is delayed and gain degradation that is an abnormality of detection sensitivity of the linear air fuel ratio sensor. COPYRIGHT: (C)2009,JPO&INPIT