Abstract: A cylinder intake air amount calculating apparatus for an internal combustion engine that calculates a cylinder intake air amount, which is an amount of fresh air sucked in a cylinder of the engine using an intake air pipe model equation which is obtained by modeling an intake pipe of the engine, is provided. An intake air flow rate is obtained. The cylinder intake air amount is calculated by applying the intake air flow rate and a preceding value of the cylinder intake air amount to the intake pipe model equation. A predicted intake air flow rate which is a predicted value of the intake air flow rate is calculated. A predicted cylinder intake air amount which is a predicted value of the cylinder intake air amount is calculated by applying the predicted intake air flow rate and the cylinder intake air amount to the intake pipe model equation.

Abstract: A method of controlling fuel composition learning includes steps of monitoring changes in airflow within an engine to determine steady state conditions. The method further includes steps of initiating a fuel composition learning process during steady state conditions. A current fuel component concentration factor is updated using a temporary fuel component concentration factor. The temporary fuel component concentration factor is calculated as the average of an air/fuel correction factor. Once the current fuel component concentration factor is updated, the temporary fuel component concentration factor is reset. The air/fuel correction factor is reset to reflect any difference that existed between the temporary fuel component concentration factor and the air/fuel correction factor at the update time.

Abstract: A cylinder intake air amount calculating apparatus for an internal combustion engine for calculating a cylinder intake air amount which is an amount of fresh air sucked into a cylinder of the engine, is provided. An intake air flow rate, which is a flow rate of fresh air passing through an intake air passage of the engine, is obtained, and an intake pressure and an intake air temperature of the engine are detected. A theoretical cylinder intake air amount is calculated based on the intake pressure, the intake air temperature, and a volume of the cylinder. A volumetric efficiency of the engine is calculated by dividing a preceding calculated value of the cylinder intake air amount by the theoretical cylinder intake air amount. The cylinder intake air amount is calculated using the volumetric efficiency, the intake air flow rate, and the preceding calculated value of the cylinder intake air amount.

Abstract: A method of controlling fuel composition learning includes steps of monitoring changes in airflow within an engine to determine steady state conditions. The method further includes steps of initiating a fuel composition learning process during steady state conditions. A current fuel component concentration factor is updated using a temporary fuel component concentration factor. The temporary fuel component concentration factor is calculated as the average of an air/fuel correction factor. Once the current fuel component concentration factor is updated, the temporary fuel component concentration factor is reset. The air/fuel correction factor is reset to reflect any difference that existed between the temporary fuel component concentration factor and the air/fuel correction factor at the update time.

Abstract: A method of controlling fuel composition learning includes steps of monitoring changes in airflow within an engine to determine steady state conditions. The method further includes steps of initiating a fuel composition learning process during steady state conditions. A current fuel component concentration factor is updated using a temporary fuel component concentration factor. The temporary fuel component concentration factor is calculated as the average of an air/fuel correction factor. Once the current fuel component concentration factor is updated, the temporary fuel component concentration factor is reset. The air/fuel correction factor is reset to reflect any difference that existed between the temporary fuel component concentration factor and the air/fuel correction factor at the update time.

Abstract: A cylinder intake air amount calculating apparatus for an internal combustion engine for calculating a cylinder intake air amount which is an amount of fresh air sucked into a cylinder of the engine, is provided. An intake air flow rate, which is a flow rate of fresh air passing through an intake air passage of the engine, is obtained, and an intake pressure and an intake air temperature of the engine are detected. A theoretical cylinder intake air amount is calculated based on the intake pressure, the intake air temperature, and a volume of the cylinder. A volumetric efficiency of the engine is calculated by dividing a preceding calculated value of the cylinder intake air amount by the theoretical cylinder intake air amount. The cylinder intake air amount is calculated using the volumetric efficiency, the intake air flow rate, and the preceding calculated value of the cylinder intake air amount.

Abstract: A cylinder intake air amount calculating apparatus for an internal combustion engine is provided. The cylinder intake air amount calculating apparatus calculates a cylinder intake air amount which is an amount of fresh air sucked in a cylinder of the engine using an intake air pipe model equation which is obtained by modeling an intake pipe of the engine. An intake air flow rate which is a flow rate of fresh air passing through the intake pipe of the engine is obtained. The cylinder intake air amount is calculated by applying the intake air flow rate and a preceding value of the cylinder intake air amount to the intake pipe model equation. A predicted intake air flow rate which is a predicted value of the intake air flow rate is calculated. A predicted cylinder intake air amount which is a predicted value of the cylinder intake air amount is calculated by applying the predicted intake air flow rate and the cylinder intake air amount to the intake pipe model equation.