PURPOSE: To suppress extension and spread of abnormality by selectively executing active diagnosis control, such as control of restoration of abnormality, control of prevention of deterioration of operability, and control of prevention of worsening of exhaust gas characteristics, based on an abnormal object and a vehicle running state when abnormality is detected.
CONSTITUTION: In a device wherein an injector 4, an ignition plug 5, an EGR valve 7, an ISC valve 10, and a pump 13 for secondary air are controlled according to output signals from various sensors to detect an operation state, diagnosis items, such as a misfire, lowering of the function of a catalyst, abnormality of an O2 sensor, abnormality of an evaporator, abnormality of an EGR function, abnormality of a secondary air feed system, and abnormality of a fuel meter are set in a control unit 27. Based on an individual diagnosis result, a control order being most proper is selected and controlled according to a current operation state. The priority order of the selection and execution is set in the order of restoration control of abnormality, control of ensurance of operability of a vehicle, control of prevention of worsening of exhaust gas characteristics, and control of prevention of worsening of fuel consumption characteristics.
KOUHIRA TAKASHI
MIURA KIYOSHI
TAKAKU YUTAKA
KONO KAZUYA
