| 摘要 |
PURPOSE:To detect abnormalities in an EGR system with high responsive property by judging whether or not negative control pressure given to an EGR valve within an EGR abnormality judging region falls outside a predetermined pressure region. CONSTITUTION:An engine controller 8 reads negative control pressure to an EGR valve 10 detected by a pressure detector 13 when the presence of running requirements in the abnormal EGR judging region of the running range of an engine 1 subjected to EGR by an EGR valve 10 with reference to a map is judged from the engine rotational frequency, intake pipe pressure and cooling water temperature detected sensors 3, 4, 7. By judging whether or not the negative control pressure is outside a predetermined range, is detected abnormalities in the EGR system including the EGR valve 10. Thus, since the abnormalities are detected irrespective of exhaust gas without being affected by the atmospheric temperature of engine room temperature or the like, the abnormalities in the EGR system can be detected with high accuracy and responsive property to improve the durability and heat resisting property. |
