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

Claim 1

An electromagnetically controlled fuel injection valve for internal combustion engines, comprising: a body (2) having a lower injection nozzle (3) provided with an injection passage; an injection chamber (6) into which the fuel is supplied under pressure; a needle (4) moving axially in an elongated cavity (5) of said body and of said nozzle between a first position in which is closed the communication between said injection chamber (6) and said injection passage and a second position in which said communication is open; an upper electromagnetic metering valve (10) provided with an axially movable pin (11) which controls fuel flow through a discharge hole (A) from a control chamber (9) into which fuel is supplied under pressure, the needle in said elongated cavity (5) being kept in the said first and second position respectively when the fuel pressure in said control chamber (9) is greater or lower than a predetermined value, said electromagnetic metering valve being housed in a seat provided on the upper surface of the fuel injection valve; a head (13) protruding from the upper part of said body and including an axial hole of constant diameter which is coaxial with said elongated cavity (5) of said body (2) and in which there is disposed a first insert (16) provided with said discharge hole (A), and including further a radial hole (Z) the axis of which is orthogonal to the axis of said axial hole and which is in communication with said axial hole and with a source of pressurized fuel, characterized in that said head (13) further accommodates a second insert (15) provided with said radial hole (Z), and in that said axial hole of constant diameter completely passes through said head (13) and defines with said inserts (15, 16) and with the upper extremity of said needle (4) said control chamber (9) into which the fuel is supplied under pressure through said radial hole (Z).