Air amount detector for internal combustion engine

An apparatus for calculating an air amount charged in a cylinder of an engine, the apparatus comprising:

• an airflow meter disposed upstream of a throttle valve in an intake passage leading intake air to the cylinder, the airflow meter outputting an output signal indicative of detected air amount;
• first calculation means for calculating a compensated output signal by applying a compensation process to the output signal from the airflow meter, the compensation process being arranged to compensate for a response delay of the airflow meter;
• and
• second calculation means for calculating the air amount charged in the cylinder from the compensated output signal in the first calculation means based on an intake air system model which associates the compensated output signal and the air amount charged in the cylinder, the intake air system model modeling a behavior of the intake air flowing from downstream of the throttle valve to the cylinder.

A method for determining an amount of air in a cylinder of an internal combustion engine, comprising:

• detecting an amount of intake air flowing through an intake air passageway;
• determining a compensation value for a response delay of the detection of the intake air flow amount;
• and
• determining an air amount in a cylinder using an intake air system model modeling a behavior of the intake air passing through a throttle valve and flowing into the cylinders, wherein the air intake system model receives said compensation value to calculate an output of said intake air system model as the amount of air inside the cylinder.