Fuel injector for a common-rail injection system having injection rate shaping

The device has an injection nozzle with a nozzle needle (31) and a control chamber (3) divided into 3 sections (13,15,17) by a control piston (11) with two grooves with a sliding element between them and separates a high pressure connection from a feed channel to the nozzle needle with the nozzle closed. A hydraulic connection (55) controlled by a valve (57) is arranged between the high pressure connection (1) or the second (15) of the 3 sections and the nozzle needle feed channel (5).