| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that when so-called external EGR control is effected, specific fuel consumption is sometimes decreased by retarding the ignition-timing. SOLUTION: An internal combustion engine is equipped with an exhaust-gas recirculation system for recirculating exhaust-gas downstream of a throttle valve in the intake system, and a variable valve-timing mechanism for controlling opening/closing timing for at least either one of the intake valve and the exhaust valve. By the exhaust-gas recirculation control, according to the state of operation of the internal combustion engine, a changeover is executed between an exhaust-gas recirculation by the exhaust-gas recirculation system and a valve-timing control by the variable valve-timing mechanism. A retard quantity of ignition timing in execution of the exhaust-gas recirculation by the exhaust-gas recirculation system is learned. If the learned retard quantity is higher than the amount of determination of recirculation implementation to be set on the basis of the specific fuel consumption, exhaust-gas recirculation by the exhaust-gas recirculation system is suspended, and the valve timing control is performed by the variable-valve timing mechanism wherein at the ignition timing with the learned retard quantity, the specific fuel consumption is at most the amount of determination of recirculation implementation. COPYRIGHT: (C)2010,JPO&INPIT
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