Abstract: A mechanically actuated electronically controlled fuel injector (MEUI) includes a first electrical actuator that controls the position of a spill valve, and a second electrical actuator to control pressure on a closing hydraulic surface associated with a directly operated nozzle check valve. The fuel injector is actuated via rotation of a cam to move a plunger to displace fuel from a fuel pumping chamber either to a spill passage, or at high pressure out of a nozzle outlet of the fuel injector for an injection event. The minimum controllable fuel injection quantity, especially as it relates to small closely coupled post injections following a large main injection, is accomplished by the inclusion of a Z orifice passage that maintains a fluid connection between a needle control chamber and the nozzle supply passage.

Abstract: A mechanically actuated electronically controlled fuel injector (MEUI) includes a first electrical actuator that controls the position of a spill valve, and a second electrical actuator to control pressure on a closing hydraulic surface associated with a directly operated needle valve. The fuel injector is actuated via rotation of a cam to move a plunger to displace fuel from a fuel pumping chamber either to a spill passage, or at high pressure out of a nozzle outlet of the fuel injector for an injection event. The minimum controllable fuel injection quantity, especially as it relates to small closely coupled post injections following a large main injection, is accomplished by the inclusion of a variable flow rate valve that restricts fluid flow from a needle control chamber toward a drain, but is relatively unrestricted to high pressure fluid flow toward the needle control chamber.

Abstract: A mechanically actuated electronically controlled fuel injector (MEUI) includes a first electrical actuator that controls the position of a spill valve, and a second electrical actuator to control pressure on a closing hydraulic surface associated with a directly operated nozzle check valve. The fuel injector is actuated via rotation of a cam to move a plunger to displace fuel from a fuel pumping chamber either to a spill passage, or at high pressure out of a nozzle outlet of the fuel injector for an injection event. The minimum controllable fuel injection quantity, especially as it relates to small closely coupled post injections following a large main injection, is accomplished by the inclusion of a Z orifice passage that maintains a fluid connection between a needle control chamber and the nozzle supply passage.