Nozzle unit for injection valve for dosing fuel into combustion chamber of internal combustion engine, has pressure discharge area allowing groove in closing position of needle to communicate with recess of body upstream to seating area

摘要

The nozzle unit has a nozzle body (16) with a recess (17) and forming a conical seat area within an area of a nozzle dome (27), where a nozzle needle (24) is arranged in the recess of the body. An annular groove extends around the circumference of the nozzle needle. A pointing pin cooperates with the seating area in a closing position of the nozzle needle for preventing a fluid flow to an injecting hole (28) of the body. A pressure discharge area allows the annular groove in the closing position of the needle to communicate with the recess of the body upstream to the seating area.