Variable volume common rail

The present invention discloses a fuel rail (2) for a fuel injection system. The fuel rail (2) in accordance with the present invention includes a fixed volume chamber (2a) and a variable volume chamber (2b) which are fluidly connected to each other. The volume of the variable volume chamber (2b) is adjusted based on the engine (3) operating conditions and the rail pressure. The volume of the variable volume chamber (2b) is varied by means of a plunger (8) assembly the position of which is controlled by a control unit (6).