Common rail fuel injection system and fuel injector for same

A fuel injection system is provided which includes a source of high pressure fuel, a low pressure fuel reservoir, and at least one fuel injector which has an injector body that defines a nozzle chamber, a needle control chamber, a needle control vent, a fuel inlet, and a nozzle outlet. A high pressure line extends between the source of high pressure fuel and the fuel inlet. A low pressure line extends between the low pressure fuel reservoir and the needle control vent. A needle control valve is positioned in the injector body and includes a poppet valve member with a first position in which the needle control chamber is fluidly connected to the fuel inlet but closed to the needle control vent. The poppet valve also has a second position in which the needle control chamber is closed to the fuel inlet but open to the needle control vent. A needle valve is positioned in the injector body and includes a one piece needle valve member with a closing hydraulic surface exposed to fluid pressure in the needle control chamber, and an opening hydraulic surface exposed to fluid pressure in the nozzle chamber.