| 摘要 |
PURPOSE:To perform reliable diagnosis of an exhaust gas recirculating device without erroneous decision, by a method wherein, when an air-fuel ratio learning high land correction factor is below a given value, diagnosis is prohibited. CONSTITUTION:A microcomputer 50 performs diagnosis of an exhaust gas recirculating device as well as control of an fuel injection amount. From an intake air flow rate detected by an airflow meter 3 and the number of revolutions of an internal combustion engine 1 detected by a number of revolutions sensor 56, an air amount per one stroke of an engine is calculated, and when it exceeds a lower limit value and is below an upper limit value, an air-fuel ratio learning high land correction factor for control of an air-fuel ratio is inputted. When the air-fuel ratio learning high land factor is below a given value, reset is made so that diagnosis is prohibited. Thus, only when diagnosis is prohibited and an atmospheric pressure is not so low and reliably accurate diagnosis is effected, diagnosis is executed during lowering of an atmospheric pressure, e.g. during running on a high land. |
