Intake system for internal combustion engines

An intake system for an internal combustion engine comprising working chamber means having a volume which changes cyclically between a top dead center of a smallest volume and a bottom dead center of a largest volume, intake passage means adapted to be cyclically opened to said working chamber means in an intake stroke which starts prior to said top dead center, control valve means provided in said intake passage means for closing said intake passage means so that intake air flow to said working chamber means is substantially interrupted and for cyclically opening said intake passage means, reversing means provided in said intake passage means upstream said control valve means and spaced apart from said control valve means by a predetermined distance for reversing a negative pressure wave produced in the intake passage means when said control valve means is opened, timing control means for operating said control valve means synchronously with rotation of the engine and retarding opening timing of the control valve means so that the control valve means is opened after top dead center of the working chamber means by a predetermined value in a first operating range including at least a low speed, high load engine operating range and the control valve means is opened at an advanced timing in a second operating range other than said first operating range so that the intake air flow is admitted to said working chamber means from said control valve means as soon as said intake stroke is started.