FUEL INJECTOR EQUIPPED WITH A METERING SERVOVALVE FOR AN INTERNAL COMBUSTION ENGINE

摘要

A fuel injector has an injector body and a control rod, which is movable in the injector body along an axis to control the opening/closing of a nozzle that injects fuel into a cylinder of the engine; the injector body houses a metering servovalve having a control chamber, which is axially delimited by the control rod and communicates with an inlet and with a discharge channel; the metering servovalve is provided with a shutter, which slides axially on an axial guide, from which the discharge channel exits, to open and close the discharge channel and, in consequence, vary the pressure in the control chamber; the discharge channel has three restrictions having calibrated passage sections and arranged in series with each other to divide the pressure drop along the discharge channel.

主权项

1. A fuel injector for an internal combustion engine, the injector ending with a nozzle to inject fuel into an associated engine cylinder and comprising:
a hollow injector body extending along an axial direction; a metering servovalve housed in said injector body and comprising:
an electro-actuator;a control chamber communicating with a fuel inlet and with a fuel discharge channel, the pressure in said control chamber controlling the opening/closing of said nozzle;a shutter axially movable in response to the action of said electro-actuator between a closed position, in which an outlet of said discharge channel is closed, and an open position, in which the discharge channel is open, to vary the pressure in said control chamber; and wherein said discharge channel comprises three restrictions having calibrated passage sections and arranged in series with each other so as to cause respective pressure drops when said discharge channel is open.