Electromagnetically-controlled fuel injection valve for i.c. engines

Claim 1

An electromagnetically-controlled fuel-injection valve for i.c. engines, comprising: a body having a lower injection nozzle provided with an injection passage; a needle movable axially in an elongated cavity of said body and of said nozzle between a first position in which communication is closed between an injection chamber to which fuel is supplied under pressure through a conduit and said injection passage, and a second position in which said communication is open; a head protruding from an upper part of said body and including an axial hole coaxial with said elongated cavity and in which there is disposed a first insert provided with a discharge hole, and also including a radial hole communicating with said axial hole and in which there is disposed a second insert provided with an inlet hole, said axial hole defining with said inserts and with an upper extremity of said needle a control chamber to which the fuel is supplied under pressure through said radial hole wherein said control chamber does not communicate with said injection chamber; and an electromagnetic metering valve provided with an obturator for controlling passage through said discharge hole to keep the needle in said first and second position respectively when the fuel pressure in said control chamber is respectively greater and lower than a predetermined value, said electromagnetic metering valve being housed in a seat provided on an upper surface of said head and an upper part of said conduit also being located in said head wherein said head is fixed mechanically to said body.