Air-fuel ratio control apparatus of internal combustion engine and control method for the same

Abstract

An air-fuel ratio control apparatus of an internal combustion engine is provided which enables highly accurate calibration of an air-fuel feedback correction value to be completed in a short time, thus avoiding adverse influences on the emissions. The engine load is fixed when the air-fuel ratio or purge concentration is calibrated from the behavior of the air-fuel ratio feedback correction value. Thus, no change is observed in the engine load even if the driver operates the accelerator pedal to adjust the accelerator pedal position so as to change the required torque, and the air-fuel ratio of the air-fuel mixture is stabilized. Accordingly, air-fuel ratio calibration or purge concentration calibration can be promptly accomplished with high accuracy. Furthermore, while the engine load is being adjusted, the output torque is controlled in accordance with the required torque by adjusting the ignition timing. Thus, the required torque can be sufficiently reflected by the output torque even when calibration is carried out with the engine load fixed.

Dependencies are inferred from the claim text.