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The injector 10 for intermittently injecting fuel under high pressure in an internal combustion engine is provided with an injector valve member (18). The movement of this injector valve member (18) to open and close a fuel discharge orifice (24) is controlled by the fuel pressure in a control chamb

The injector 10 for intermittently injecting fuel under high pressure in an internal combustion engine is provided with an injector valve member (18). The movement of this injector valve member (18) to open and close a fuel discharge orifice (24) is controlled by the fuel pressure in a control chamber (40) acting on a valve piston (26) on the side opposite to the discharge orifice (24). A cylindrical member (36) surrounds the upper part (30) of the valve piston (26). Energization of a solenoid (44) results in the opening of a pilot valve (46) and a subsequent quick drop of the fuel pressure in the control chamber (40). The solenoid (44) in addition to its function as a high speed actuator for the pilot valve (46) is also used to carry and transmit the force resulting from the fuel pressure in the control chamber (40) and acting on the cylindrical member (36), on the solenoid (44) and on further members (48, 50, 52, 14). Since the solenoid (44) can therefore be mounted directly within the injector housing (14), the design of the injector (10) can be very compact and simple.

대표청구항 ▼

A fuel injector for intermittently injecting fuel into a combustion chamber of an internal combustion engine, comprising an injector housing (14) with a valve seat (22) and at least one discharge orifice (24), an elongated injector valve member (18) provided with a piston member (26) and mounted wit

A fuel injector for intermittently injecting fuel into a combustion chamber of an internal combustion engine, comprising an injector housing (14) with a valve seat (22) and at least one discharge orifice (24), an elongated injector valve member (18) provided with a piston member (26) and mounted within said housing (14) for engagement with said valve seat (22) for closing said discharge orifice (24), said injector valve member (18) being shiftable in its axial direction to be momentarily lifted from said valve seat (22) to open said discharge orifice (24) to allow for the injection of a desired quantity of fuel into the combustion chamber of the internal combustion engine, a control chamber (40) provided within said housing (14) and being connectable to a fuel supply line (12); the fuel pressure in said control chamber (40) acting upon said piston member (26) of said injector valve member (18) to force the latter against said valve seat (22), means (34, 38, 44, 46; 172, 182) for quickly reducing and quickly restoring the fuel pressure in said control chamber (40) to allow for the momentary axial movement of said injector valve member (18), said means for quickly reducing and restoring the fuel pressure in said control chamber (40) including a first orifice (34) and a second orifice (38) opening into said control member (40), electromagnetically controlled pilot valve means (46; 182) for closing and temporarily opening one end of said second orifice (38) and a solenoid (44; 172) for opening said pilot valve means (46; 182) depending upon applied electric pulses of a predetermined duration; at least one first member (36; 166) defining in part said control chamber (40) and being subject at least to the fuel pressure present in said control chamber (40), said first member (36; 166) being in connection with further member means (44, 48, 50, 52, 54, 14; 51, 53; 107, 172) including plural members and said solenoid (44; 172) for transmitting the hydraulic forces acting upon said first member (36, 166) to said further member means, said solenoid (44; 172) in addition to its function as an actuating device for said pilot valve (46, 182) being also used to carry and to transmit said forces from one of said plural members of said further member means (50, 107, 166) to a next one of said plural members of said further member means (52, 53).