To provide a control system of an internal combustion engine for efficiently resolving deviation of a rotational speed from a target rotational speed by changing a control method of the internal combustion engine in accordance with causes of deviation of the rotational speed from the target rotational speed.
A torque-corresponding value such as estimated graphically shown torque is found, and the degree of variation in a plurality of cycles in the past is expressed numerically as an index value (i.e. a locus length). If a deviation index value is smaller than a specified 1st determination value, an intake air flow of the internal combustion engine is corrected. If the deviation index is at least the 1st determination value, the ignition timing for the internal combustion engine is corrected. If the deviation index value is at least a specified 2nd determination value which is larger than the 1st determination value, fuel-supply quantity is also corrected in addition to the correction of the ignition timing of the internal combustion engine.
UEDA KOICHI
Mamoru Takada
Atsushi Hirayama
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