Three-way needle control valve and dual fuel injection system using same

A dual fuel system comprising:

• a dual fuel injector with a first fuel inlet, a second fuel inlet, a drain outlet, a first nozzle outlet set and a second nozzle outlet set, and having disposed therein a first direct control needle valve with a closing hydraulic surface positioned in a first needle control chamber, and a second direct control needle valve with a closing hydraulic surface positioned in a second needle control chamber, and including a first electronically controlled three way valve and a second electronically controlled three way valve;
• a liquid fuel common rail fluidly connected to the first fuel inlet;
• a gaseous fuel common rail fluidly connected to the second fuel inlet;
• each of the first and second electronically controlled three way valves include a respective first or second control valve member trapped to move between contact with a respective first or second conical valve seat and contact with a respective first or second flat valve seat;
• wherein the first electronically controlled three way valve fluidly connects a first pressure communication passage to the first needle control chamber when the first control valve member is in contact with the first conical valve seat, and fluidly connects the drain outlet to the first needle control chamber when the first control valve member is in contact with the first flat valve seat;
• and
• wherein the second electronically controlled three way valve fluidly connects a second pressure communication passage to the second needle control chamber when the second control valve member is in contact with the second conical valve seat, and fluidly connects the drain outlet to the second needle control chamber when the second control valve member is in contact with the second flat valve seat;
• the first fuel inlet is surrounded by an inner conical seat and an outer conical seat, which are concentric;
• the second fuel inlet opens between the inner conical seat and the outer conical seat;
• a first armature of the first electrically controlled three way valve and a second armature of the second electronically controlled three way valve move along a common centerline.