Mud guard forming a lateral motor sound insulation device

The noise insulation for a motor vehicle wing has an acoustic screen (6) between the engine compartment and the wing internal volume. The screen extends between a wing support (7) and the chassis longitudinal beam (3) on the same side of the vehicle. The screen can have a noise absorbent surface turned towards the engine compartment. The screen can engage the bonnet of the vehicle. Claims include a wing using the insulation.