Fuel injector and method using two, two-way valve control valves

Abstract

A fuel injector that contains no springs and is controlled by a valve assembly that has more than two modes of operation. The fuel injector includes a housing which has a supply port, a drain port and a cylinder passage that is in fluid communication with an intensifier. The intensifier moves between a first position and a second position within a fuel chamber. The fuel chamber is coupled to a fuel port. Movement of the intensifier into the second position pressurizes the fuel within the fuel chamber. The pressurized fuel opens a needle valve so that fuel is ejected through an aperture of the housing. The cylinder passage is coupled to a first fluid control valve and a second fluid control valve. Each control valve can be actuated between a closed position and an open position. When the first control valve is moved to the open position the supply port is in fluid communication with the cylinder passage so that a fluid flows through the passage to push the intensifier to the second position and eject fuel from the ejector. When the second control valve is actuated to the open position the cylinder passage is coupled to the drain port. The intensifier is coupled to a supply line that provides fluid to move the intensifier back to the first position. The needle valve is also coupled to the return line to move the needle back to a closed position.