ENGINE INTAKE SYSTEM FAULT DIAGNOSIS DEVICE

摘要

PROBLEM TO BE SOLVED: To precisely detect a minute amount of leakage of intake air by utilizing two parameters to prevent erroneous determination.;SOLUTION: An engine intake system fault diagnosis device comprises an air/fuel ratio calculation means for calculating an air/fuel ratio calculation value from at least a fuel injection, engine rotation speed detected by an engine rotation speed detection means, and an intake airflow detected by an intake airflow detection means, and an air/fuel ratio detection means for detecting an air/fuel ratio. The diagnosis device diagnoses the intake system as being faulty when the difference between an estimated intake pressure value calculated by an estimated intake pressure calculation means and an actual intake air pressure value detected by an intake air pressure detection means is larger than a first threshold value and when the difference between an air/fuel ratio calculated by the air/fuel ratio calculation means and an actual air/fuel ratio detected by the air/fuel ratio detection means is larger than a second threshold value.;COPYRIGHT: (C)2011,JPO&INPIT