Patent ID: 8366018

Claim:
A fuel injector comprising: a first port for coupling to a source of intensifier actuation fluid under pressure and a second port for coupling to an intensifier actuation fluid vent; a third port for coupling to fuel under pressure; an intensifier having an intensifier piston and an intensifier plunger; a first control valve coupled to the first and second ports and to the intensifier piston for controlling an intensifier actuation fluid to and from the intensifier piston; a needle in a needle chamber; a needle closure piston coupled to fuel under pressure to encourage the needle to a closed position; a needle control pin disposed to counteract the needle closure piston when fuel under pressure is provided to the needle control pin; a second control valve coupled between the third port and the needle control pin to control fuel pressure provided to the needle control pin; and a check valve coupled to allow fuel flow from a source of fuel to the needle chamber, and to prevent fuel flow back to the source of fuel; the intensifier actuation fluid not being fuel; whereby the first control valve determines whether intensification occurs, and the second control valve controls fuel injection based on the pressure of fuel in the third port if intensification is not occurring, and controls fuel injection based on the intensified fuel pressure when intensification is occurring.