| 摘要 |
PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine, for detecting a failure of an EGR valve at its open side, and in this condition, maintaining the best possible center air-fuel ratio, and suppressing worsening of exhaust and the erosion of a catalyst.SOLUTION: There is provide the control device for the internal combustion engine. The internal combustion engine includes an exhaust side turbine, a front oxygen concentration sensor, an exhaust emission control catalyst, a rear oxygen concentration sensor, an intake side compressor, an exhaust gas recirculation passage, and an exhaust gas recirculation control valve, performs feedback to achieve a front center air-fuel ratio on the basis of the output of the front oxygen concentration sensor, and controls the front center air-fuel ratio on the basis of the output of the rear oxygen concentration sensor. When a failure of the EGR valve at its open side occurs, the control device detects the failure using the behavior of a front center air-fuel ratio correction amount, and after detecting the failure, the control device performs center air-fuel ratio control in such a special mode as to repeat the control of a theoretical air-fuel ratio on the front side only for a predetermined time and then on the rear side only for a predetermined time and the control on the front side only again. |
