valve control system for an internal combustion engine

The invention relates to a valve control system for a system interne.Ce combustion engine comprises a housing (3) with a cover member (8), a phase adjustment mechanism for hydraulically change the rotational phase of a crankshaft and a camshaft (1), a supply / discharge rod (16) arranged through a through hole of the cover member and connected to the phase adjustment mechanism, a ring of sealing (32) for sealing a space between the rod (16) and the phase adjustment mechanism, a tapered surface to increase the diameter of the through hole towards the outside of the housing and a projection (34) formed with the cover member in a radially inner region thereof to protrude in the axial direction of the system, where the through hole (33) is formed in the projection (34). The invention is particularly applicable to internal combustion engines.