The invention relates to an engine control valve including a body defining an inner duct and comprising a flap (10) mounted such that it can pivot by means of a shaft (12), said flap (10) comprising a first portion (11). The flap can pivot between an open position allowing the passage of fluid into the duct and a closed position in which the flap (10) comes into contact with a flat seal (100) of the flap. The outer contour of the seal (100) surrounds the outer contour of the flap (10), said seal (1) comprising an opening (6) and a solid portion (3). The above-mentioned first portion (11) seals the opening (6) in the seal (1) when the flap (10) is in a closed position. The seal (100) includes a reinforcement area (101) in the solid portion (3) thereof, such as to prevent the seal (100) from deforming owing to the high pressure and high temperature of the gases in the valve.