INTERNAL COMBUSTION ENGINE SYSTEM

To suppress a torque step which is formed at the changeover of drive cams.SOLUTION: This internal combustion engine system has a plurality of cylinders. Intake valves are arranged at a plurality of the cylinders, respectively, and two kinds of intake cams different in cam profiles are arranged in response to the respective intake valves. A throttle valve for adjusting suction air amounts introduced into an intake passage by being opened and closed is arranged in the intake passage of the internal combustion engine. The internal combustion engine system further comprises a changeover mechanism and a control device. The changeover mechanism switches drive cams for actually driving the intake valves between the two kinds of the intake cams. When switching the drive cams, the control device starts the control of the throttle valve to a direction in which a difference between the air amounts which are introduced into the cylinders become small before and after the changeover of the drive cams simultaneously with the valve-closing timing of the intake valves immediately before the changeover of the drive cams in the cylinder in which a stroke immediately before the changeover of the drive cams becomes an intake stroke.SELECTED DRAWING: Figure 1 【課題】駆動カムの切り替え時に発生するトルク段差を抑制する。【解決手段】本発明の内燃機関システムは、複数の気筒を有している。複数の気筒のそれぞれには吸気弁が配置され、吸気弁それぞれに対応して、カムプロフィールの異なる２種類の吸気カムが配置される。また内燃機関の吸気通路には、開閉により吸気通路に導入される吸入空気量を調整するスロットル弁が配置される。内燃機関システムは、更に、切替機構と制御装置とを備える。切替機構は、吸気弁を実際に駆動する駆動カムを２種類の吸気カムの間で切り替える。制御装置は、駆動カムを切り替える際に、駆動カムの切り替え直前の行程が吸気行程となる気筒における、駆動カムの切り替え直前の吸気弁の閉弁タイミングと同時に、駆動カムの切り替え前後で気筒内に導入される空気量の差が小さくなる方向に、スロットル弁の制御を開始するように構成されている。【選択図】図１