Patent ID: 7942349

Claim:
A fuel injector comprising: (a) an injector body comprising a primary fuel chamber, a fuel inlet connected to the primary fuel chamber, a secondary fuel chamber, an inwardly extending member separating the primary and secondary fuel chambers and surrounding a valve passage connecting the primary and secondary fuel chambers, a fuel outlet connected to the secondary fuel chamber, and a valve seat around the fuel outlet; (b) a reciprocating valve extending through the fuel outlet, secondary fuel chamber, valve passage, and primary fuel chamber; and (c) a fuel-metering passage positioned between said fuel chambers and arranged to permit only restricted fuel flow from the primary fuel chamber into the secondary fuel chamber; (d) wherein the valve and injector body are arranged so that movement of the valve in a first direction relative to the injector body causes engagement of the valve and the valve seat and substantially prevents fuel flow through the fuel outlet; (e) wherein the valve and injector body are arranged so that movement of the valve in a second direction relative to the injector body, the second direction being opposite the first direction, causes disengagement of the valve and the valve seat and enables fuel flow through the fuel outlet; (f) wherein the inwardly extending member at least partially engages the valve as it passes through the valve passage; and (g) wherein the fuel injector is structured so that, with the valve disengaged from the valve seat and fuel flowing through the fuel outlet, the restricted fuel flow from the primary fuel chamber into the secondary fuel chamber results in a fuel pressure differential between the primary and secondary fuel chambers that in turn results in a flow-dependent force on the valve in the first direction, which force increases with increasing fuel flow through the fuel outlet.