CONTROLLER FOR INTERNAL COMBUSTION ENGINE

A controller for an internal combustion engine acquires a rotation speed, a load factor, and a current torque from sensors mounted on a vehicle. The controller calculates a predicted torque and a predicted blow-by gas amount based on the rotation speed and the load factor. The controller calculates an estimated richness ratio indicating a ratio at which an air-fuel mixture in a combustion chamber has been enriched by blow-by gas, based on the predicted blow-by gas amount and a difference between the current torque and the predicted torque. The controller corrects a fuel injection amount of the fuel injection valve based on the estimated richness ratio.