Abstract: A control system for an internal combustion engine having a throttle valve disposed in an intake passage of the engine is provided. A wide-open intake air amount, which is an intake air amount corresponding to a state where the throttle valve is fully opened, is calculated according to the engine rotational speed, and a theoretical intake air amount, which is an intake air amount corresponding to a state where no exhaust gas of the engine is recirculated to a combustion chamber of the engine, is calculated according to the wide-open intake air amount and the intake pressure. An intake air amount of the engine is detected or estimated, and an amount of the evaporative fuel/air mixture supplied through the evaporative fuel passage to the intake passage is calculated. An intake gas amount is calculated by correcting the intake air amount using the evaporative fuel/air mixture amount, and an exhaust gas recirculation ratio is calculated using the theoretical intake air amount and the intake gas amount.

Abstract: A control apparatus for an internal combustion engine having a throttle valve disposed in an intake passage of the engine is provided. A wide-open intake air amount, which is an intake air amount corresponding to a state where the throttle valve is fully opened, is calculated, and a theoretical intake air amount, which is an intake air amount corresponding to a state where no exhaust gas of the engine is recirculated to a combustion chamber of the engine, is calculated according to the wide-open intake air amount and the intake pressure. An air-fuel ratio correction amount and a learning value thereof are calculated according to the detected air-fuel ratio, and a reference intake air amount is calculated using the intake pressure, the engine rotational speed, the air-fuel ratio correction amount, and the learning value.

Abstract: A control apparatus for an internal combustion engine having a throttle valve disposed in an intake passage of the engine is provided. A wide-open intake air amount, which is an intake air amount corresponding to a state where the throttle valve is fully opened, is calculated, and a theoretical intake air amount, which is an intake air amount corresponding to a state where no exhaust gas of the engine is recirculated to a combustion chamber of the engine, is calculated according to the wide-open intake air amount and the intake pressure. An air-fuel ratio correction amount and a learning value thereof are calculated according to the detected air-fuel ratio, and a reference intake air amount is calculated using the intake pressure, the engine rotational speed, the air-fuel ratio correction amount, and the learning value.

Abstract: A control system for an internal combustion engine having a throttle valve disposed in an intake passage of the engine is provided. A wide-open intake air amount, which is an intake air amount corresponding to a state where the throttle valve is fully opened, is calculated according to the engine rotational speed, and a theoretical intake air amount, which is an intake air amount corresponding to a state where no exhaust gas of the engine is recirculated to a combustion chamber of the engine, is calculated according to the wide-open intake air amount and the intake pressure. An intake air amount of the engine is detected or estimated, and an amount of the evaporative fuel/air mixture supplied through the evaporative fuel passage to the intake passage is calculated. An intake gas amount is calculated by correcting the intake air amount using the evaporative fuel/air mixture amount, and an exhaust gas recirculation ratio is calculated using the theoretical intake air amount and the intake gas amount.

Abstract: A control system for an internal combustion engine having a throttle valve disposed in an intake passage of the engine is provided. A wide-open intake air amount, which is an intake air amount corresponding to a state where the throttle valve is fully opened, is calculated according to the engine rotational speed, and a theoretical intake air amount, which is an intake air amount corresponding to a state where no exhaust gas of the engine is recirculated to a combustion chamber of the engine, is calculated according to the wide-open intake air amount and the intake pressure. An actual intake air amount of the engine is detected or estimated, and an exhaust gas recirculation ratio is calculated using the theoretical intake air amount and the actual intake air amount. The engine is controlled using the calculated exhaust gas recirculation ratio.

Abstract: A control for an engine having a variable valve actuation mechanism is provided. A map indicating a correlation among a rotational speed, a gauge pressure of an intake manifold, a lift amount of an intake valve, a phase of the intake valve and an intake air amount of the engine under a reference condition of a predetermined reference atmospheric pressure and a predetermined reference intake air temperature is defined. An intake air amount for the reference condition is determined as a reference intake air amount by referring to the map based on a current rotational speed, a current gauge pressure, a current lift amount and a current phase. The reference intake air amount is corrected with a ratio between an air density under a current condition of a current atmospheric pressure, a current intake air temperature and a current gauge pressure and an air density under the reference condition to calculate an intake air amount for the current condition.

Abstract: A control system for an internal combustion engine having a valve operating characteristic varying device which continuously changes a lift amount of at least one intake valve. Operation of a start switch, which instructs the start of the engine is detected. The engine is started after a predetermined delay time period has elapsed from the moment the operation of the start switch is detected. The valve operating characteristic varying device is operated during the predetermined delay time period, and a failure determination of the valve operating characteristic varying device is performed.

Abstract: A control for an engine having a variable valve actuation mechanism is provided. A map indicating a correlation among a rotational speed, a gauge pressure of an intake manifold, a lift amount of an intake valve, a phase of the intake valve and an intake air amount of the engine under a reference condition of a predetermined reference atmospheric pressure and a predetermined reference intake air temperature is defined. An intake air amount for the reference condition is determined as a reference intake air amount by referring to the map based on a current rotational speed, a current gauge pressure, a current lift amount and a current phase. The reference intake air amount is corrected with a ratio between an air density under a current condition of a current atmospheric pressure, a current intake air temperature and a current gauge pressure and an air density under the reference condition to calculate an intake air amount for the current condition.