Injector valve with contoured valve seat and needle valve interface

摘要

An injector valve having a stable fuel flow while metering "single point" fuel volumes is disclosed. A metering portion of the injector valve comprises a needle valve and a valve housing including a centrally located valve housing bore that terminates in a truncated conical valve seat and cylindrical metering orifice. A transitional surface connects the valve seat to the metering orifice to gradually change the direction of fuel flow so separation and unstable flow will not occur. The needle valve is concentrically reciprocal within the valve housing bore and closes the metering orifice with a valve tip having a closure surface mating with the valve seat. The valve tip narrows from the closure surface into a pintle which extends through the metering orifice and ends in a deflection cap which shapes the spray of the valve into a hollow-cone pattern. The valve tip between the pintle and closure surface has a contoured surface that increases the flow area of the valve tip and valve seat interface to a plateau value downstream of the closure surface and then smoothly decreases the flow area from that value to where fuel exits the metering orifice.