Internal combustion engine including plural cylinders, control apparatus and control method for internal combustion engine including plural cylinders

Abstract

A combustion condition for each of plural cylinders included in an internal combustion engine is set by the following control that is performed according to an intake air amount in each of the plural cylinders. A reference cylinder is set to a cylinder in which the intake air amount is smallest, and a fuel injection amount for the reference cylinder is set to a fuel injection amount for realizing a stoichiometric air-fuel ratio. The air-fuel ratio in each of the cylinders other than the reference cylinder is set according to the intake air amount in each of the cylinders such that the torque equal to reference torque generated in the reference cylinder is generated. When this setting is performed, air-fuel ratios that are out of a predetermined region in the vicinity of the stoichiometric air-fuel ratio (i.e., air-fuel ratios that are in an avoidance region) are excluded. With respect to a cylinder in which the torque equal to the reference torque cannot be generated only by setting the air-fuel ratio, correction of the ignition timing is further performed so as to suppress a difference between the torque generated in the cylinder and the reference torque.