Fuel injection nozzle with integral solenoid valve

Claim 1

A fuel injection nozzle with integral solenoid valve for internal-combustion engines, comprising an injection nozzle body having a pressure space with a fuel injection nozzle opening and a nozzle needle movably disposed in said nozzle body and being spring-biased so as to normally close said fuel injection nozzle opening with one axial end thereof, and a multi-part solenoid valve housing including a first housing part receiving an annular magnetic coil and a second housing part disposed between said first housing part and said fuel nozzle body and having disposed therein a disc-shaped magnetic armature with an armature shaft movably supported so as to guide said magnetic armature, said armature shaft having seating faces formed at its opposite axial ends, said nozzle body and said first and second housing parts having planar end faces in engagement with one another, and said upper housing part including a pressurized fuel supply passage in communication with a fuel supply passage extending to said pressure space and having a passage opening with a seal seat disposed in said planar surface in axial alignment with said armature shaft and said nozzle body having a pressure relief channel with an opening with a seal seat arranged in the planar surface of said nozzle body and also in axial alignment with said armature shaft, said armature shaft being spring-biased to one end position so as to be normally seated on said fuel injection nozzle body for closing said pressure relief channel while the pressurized fuel passage in said upper housing part is open for supplying pressurized fuel through a passage section extending through said second housing part to the back-side of said injection nozzle, and said armature shaft being movable by energization of said coil to its opposite end position for closing said high-pressure fuel supply passage in said upper housing part and opening said pressure relief channel so as to provide for communication between said passage section in said second housing part and said pressure relief channel thereby causing a collapse of the pressure at the other axial end of said fuel injection nozzle needle permitting the opening of said nozzle needle by the fuel under pressure in said pressure space for discharging fuel from said pressure space through said nozzle opening.