Patent attributes
An intake pressure sensor is provided in an intake manifold of a first cylinder. During steady operation, intake quantities of respective cylinders are sensed with an airflow meter provided in an intake pipe of an engine, and the intake quantity of the first cylinder is compared with the intake quantities of the other cylinders to obtain intake pressure variation correction coefficients of the other cylinders. Also, average intake pressure of the first cylinder is corrected with the intake pressure variation correction coefficients to calculate average intake pressures of the other cylinders. During transient operation, estimation intake pressure is anticipated from a target opening degree of an intake throttle valve with the use of a physics model. Intake quantities of the respective cylinders are calculated with the use of the estimation intake pressure and the intake pressure variation correction coefficients.