Cylinder intake air amount calculating apparatus for internal combustion engine

A cylinder intake air amount calculating apparatus for an internal combustion engine which calculates a cylinder intake air amount which is an amount of fresh air sucked in a cylinder of said engine using an intake air pipe model equation which is obtained by modeling an intake pipe of said engine, said cylinder intake air amount calculating apparatus comprising:

• intake air flow rate obtaining means for obtaining an intake air flow rate which is a flow rate of fresh air passing through the intake pipe of said engine;
• cylinder intake air amount calculating means for calculating a present value of the cylinder intake air amount by applying the intake air flow rate and a preceding value of the cylinder intake air amount to the intake pipe model equation;
• intake air flow rate predicting means for calculating a predicted intake air flow rate which is a predicted value of the intake air flow rate;
• cylinder intake air amount predicting means for calculating a predicted cylinder intake air amount which is a predicted value of the cylinder intake air amount by applying the predicted intake air flow rate and the present value of the cylinder intake air amount calculated by the cylinder intake air amount calculating means to the intake pipe model equation without correcting the present value;
• and
• volumetric efficiency calculating means for calculating a volumetric efficiency of said engine using the preceding value of the cylinder intake air amount, wherein the intake pipe model equation includes the volumetric efficiency.