Abstract: A control system for a fuel injector is disclosed. The control system has a nozzle member with at least one orifice, and a needle check valve. The needle check valve is recipratingly disposed to open and close the at least one orifice. The control system also has a control chamber located at the base end of the needle check valve, and a control valve movable to selectively drain and fill the control chamber. The control system further has an injector body, a first piston located within the injector body, and a second piston located within the injector body. The first piston is operatively connected to the control valve to move the control valve. The second piston is located a distance from the first piston to form a coupling chamber. The control system additionally has a partial-ball check valve associated with the coupling chamber to selectively replenish the coupling chamber.

Abstract: A control system for a fuel injector is disclosed. The control system has a nozzle member with at least one orifice, and a needle check valve. The needle check valve is recipratingly disposed to open and close the at least one orifice. The control system also has a control chamber located at the base end of the needle check valve, and a control valve movable to selectively drain and fill the control chamber. The control system further has an injector body, a first piston located within the injector body, and a second piston located within the injector body. The first piston is operatively connected to the control valve to move the control valve. The second piston is located a distance from the first piston to form a coupling chamber. The control system additionally has a partial-ball check valve associated with the coupling chamber to selectively replenish the coupling chamber.