Patent ID: 8224554

Claim:
A fuel injector which is to be installed in an internal combustion engine to spray fuel from a spray hole comprising: a body having a fuel inlet and a spray hole formed therein said body also having formed therein a fuel supply path which extends from the fuel inlet to the spray hole and through which the fuel is supplied from the fuel inlet to the spray hole; a nozzle chamber defined in the fuel supply path, said nozzle chamber being greater in cross sectional area than the fuel supply path; a nozzle disposed within said nozzle chamber to be movable into or out of abutment with a seat formed on said body to block or establish fluid communication between the fuel supply path and the spray hole; a fuel pressure sensor installed in said body so as to be exposed to the fuel in said nozzle chamber to produce a signal indicative of a pressure of the fuel; and a signal wire which is joined to said fuel pressure sensor and through which the signal, as produced by said fuel pressure sensor, is outputted outside said body and a fuel drain path through which a portion of the fuel is drained outside said body at a pressure lower than that in said fuel supply path, and wherein said signal wire is disposed in said fuel drain path.