FUEL INJECTOR FOR AN INTERNAL COMBUSTION ENGINE

摘要

A fuel injector comprising an injector body having a spray aperture; a pintle extending within the injector body for axial movement between a closed position and an open position; said pintle head comprising a tapered portion engageable against the valve seat of the spray aperture and a cylindrical portion upstream of said tapered portion, an annular channel being provided defining a first part of a flow passage upstream of the spray aperture, wherein a discontinuity is provided downstream of the annular channel and upstream of the spray aperture to generate cavitation when the pintle stroke exceeds a predetermined limit to thereby generate a virtual channel of constant cross section downstream of the annular channel whereby the flow rate of the fuel flowing through said spray aperture is substantially independent of the stroke of the pintle when the pintle is in its open position.