Patent ID: 7178510

Claim:
A fuel system for use in an internal combustion engine comprising: a fuel injector having an outlet nozzle for injecting fuel for combustion in said engine; a source of high pressure fuel for supplying fuel to said injector outlet nozzle through a fuel supply path having a substantially fixed flow length; a first valve arrangement in said fuel supply path for controlling initiation of fuel injection in an injection cycle; a second valve arrangement in said fuel supply path including a valve member which is operable between first and second positions to vary the restriction to fuel flow through the second valve arrangement to vary the rate of flow of fuel to the injector outer nozzle wherein the variation of flow rate of fuel to the injector outlet nozzle throughout said injection cucle follows an injection characteristic, and an actuator for controlling the operation of the second valve arrangement throughout said injection cycle to vary a time dependent fuel injection characteristic defined by the variation of fuel injection rate throughout said injection cycle.