CONTROL SYSTEM OF SPARK IGNITION TYPE INTERNAL COMBUSTION ENGINE

PROBLEM TO BE SOLVED: To provide a control system of a spark ignition type internal combustion engine which contributes to the improvement of the ignition performance of an air-fuel mixture.SOLUTION: There is provided the control system of a spark ignition type internal combustion engine including an ignition plug 32 which is arranged in the vicinity of a center of an upper wall face of a combustion chamber 14, and ignites an air-fuel mixture. The control system of the spark ignition type internal combustion engine includes a port fuel injection valve 30 which is set in an injection direction of fuel in such a way that injected fuel progresses toward a center side of the combustion chamber 14 through an opening part 26b of an intake valve 26 when the fuel is injected during a valve-opened period of the intake valve 26. In an internal combustion engine 10 in which a tumble flow is generated in a cylinder, a gas flow speed at the surroundings of the ignition plug at ignition is controlled by changing a shape of the tumble flow according to an engine revolution speed between a normal tumble shape and a ω tumble shape. By superimposing at least a part of a fuel injection period of the port fuel injection valve 30 on a valve-opened period of the intake valve 26, the tumble flow of the ω tumble shape is generated. 【課題】この発明は、混合気の着火性向上に資する火花点火式内燃機関の制御システムを提供することを目的とする。【解決手段】燃焼室１４の上壁面の中央部付近に配置され混合気に点火するための点火プラグ３２を備える。吸気弁２６の開弁期間中に燃料が噴射された場合には噴射燃料が吸気弁２６の開口部２６ｂを通って燃焼室１４の中央部側に向かうように燃料の噴射方向が設定されたポート燃料噴射弁３０を備える。筒内にタンブル流が生成される内燃機関１０において、通常のタンブル形状とωタンブル形状との間でエンジン回転速度に応じてタンブル流の形状を変化させることで、点火時の前記点火プラグの周囲のガス流速を制御する。ポート燃料噴射弁３０の燃料噴射期間の少なくとも一部を吸気弁２６の開弁期間と重ねることでωタンブル形状のタンブル流を生成させる。【選択図】図１３