Intake system for internal combustion engine

An intake system for an internal combustion engine comprising a first valve means provided to open and close an intake passage leading to each combustion chamber, a bypass passage for introducing intake air into each combustion chamber bypassing the first valve means, and a second valve means provided to open and close the bypass passage, the first valve means being operated to close the intake passage in a light load range and to open the same in a heavy load range, and the second valve means being operated to close the bypass passage in the middle of each intake stroke, wherein the improvement comprises a first valve control means which controls the first valve means so that the opening of the intake passage is increased as the engine load increases after exceeding a predetermined value, and a second valve control means which controls the second valve means to delay the time the bypass passage is closed with increase in the engine load so that the time the bypass passage is opened substantially overlaps with the time the intake valve is opened when the engine load reaches the predetermined value.