| 摘要 |
Apparatus and method for diagnosing a fuel supply system of an internal combustion engine wherein a compensation amount (qcy) for each cylinder is determined on the basis of a deviation (DNE) of an actual operating state of the engine with respect to a desired operating state thereof, and the fuel supply system is feedback-controlled by compensating a commanded value (QFIN) of a quantity of injection of a fuel by the fuel supply system into the internal combustion engine, according to the compensation amount. The apparatus and method include respectively include a diagnosing device (52) and a diagnostic step for effecting a diagnostic compulsory adjustment (in steps S590 and S600) of an operating condition of the fuel supply system for each cylinder when the absolute value of the compensation amount (qcy) exceeds a predetermined threshold (A) (when affirmative decision is obtained in step S550), and for diagnosing the fuel supply system on the basis of a speed variation of the engine cause by the adjustment. <IMAGE> |
