HIGH OPERATION REPEATABILITY AND STABILITY FUEL INJECTION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE

摘要

The system comprises an injector (1) controlled by commands (S1, S 2 ) of a control unit. The injector (1) comprises a dosing servo valve (5) having a control chamber (26) provided with an outlet passage (42a) that is opened/closed by an open/close element (47) that is axially movable. The open/close element (47) is carried by an axial guide element (41) that is separate from an anchor (17) of an electromagnet (16). The open/close element (47) is held in the closing position by a spring (23) acting through an intermediate body (12a). Preferably, the strokes of the open/close element (47) and of the anchor (17) are chosen so as to eliminate, upon closing of the solenoid valve (5), the rebounds of the open/close element (47) subsequent to the first rebound. The control unit (100) controls an injection comprising a pre-injection and a main injection, via two distinct electrical commands (S1, S2), which are spaced apart by a dwell time (DT) such as to occur in an area (Z) of reduced variation of the amount of injected fuel; therefore, the stability of operation of the system increases as said dwell time (DT) varies.