A malfunction determining apparatus of an exhaust gas recirculation system

摘要

A malfunction determining apparatus of an exhaust gas recirculation system (1) performs an accurate determination of malfunctioning of an EGR valve (4) based on an amount of change in the actual degree of opening of the EGR valve (4). The EGR valve (4) is provided between an exhaust passage (10) and an intake passage (9) of an internal combustion engine (2) of a vehicle. An actual valve opening degree detector detects an actual valve opening degree (ELIFTD) of the EGR valve (4). A target valve opening degree calculator calculates a target valve opening degree (ETLIFTD) of the EGR valve (4). A malfunction determining part calculates an amount of change (ELIFTD-ELIFTD1) in the actual valve opening degree (ELIFTD) when an amount of change (ETLIFTD-ETLIFTD1) in the target valve opening degree is equal to or greater than a predetermined value ( alpha ) so as to determine an occurrence of malfunction in the exhaust gas recirculation system (1) based on a comparison between the amount of change (ELIFTD-ELIFTD1) in the actual valve opening degree (ELIFTD) and a second predetermined value ( beta ).