| 摘要 |
<p>PURPOSE:To suppress deterioration of exhaust gas purification characteristics caused when catalyst is deteriorated by oil. CONSTITUTION:In an engine which incorporates a lubricating system in which a metering oil pump 18 is used and an exhaust system 19 in which catalyst 20 is provided, deterioration of catalyst due to exposure to phosphorous poison is detected by counting the amount of oil consumption over a specified limit. When the deterioration of catalyst is thus detected, a lean correction is made to an air/fuel ratio in an air/fuel ratio feedback control area at low and medium loads to suppress increase of the exhaust amount of HC and CO. Also, when the deterioration of catalyst due to exposure to phosphorous poison is thus detected, the amount of ECR is increased correctively to suppress increase of the exhaust amount of NOx.</p> |
