Intake air control apparatus for engines

Abstract

An improved apparatus is provided to control supply of airflow to an engine. The engine includes a combustion chamber connected to an air intake passage and an air exhaust passage. An air intake valve selectively opens and closes the intake passage to control the supply of the airflow to the combustion chamber. An air exhaust valve selectively opens and closes the exhaust passage to control the discharge of the exhaust gas from the combustion chamber. An altering device alters a period of an overlap of the valves by changing a valve timing of valves. A first detector detects a driving state of the engine. An ECU computes a target valve timing based on the detected driving state of the engine controls the altering device based on the computed target valve timing. An adjusting device is arranged in the intake passage to adjust the supply of the airflow to the combustion chamber. The ECU computes a target amount of the airflow to be supplied to the engine in an idling state. The ECU detects the period of the valve overlap. The ECU computes a correction value to correct the target amount of the air based on the detected period of the valve overlap. The correction value is continuously variable based on the period of the valve overlap. The ECU corrects the target amount based on the correction value by increasing the target amount by the correction value and controls the adjusting means based on the corrected target amount.