A fuel injector includes an injector body and a valve stack within the injector body that includes a valve seat plate. The valve seat plate includes a pressure control passage for controlling fuel injection, and a valve seat positioned fluidly between the pressure control passage and a low-pressure drain. The valve seat plate includes a pressure-limiting annular groove that extends circumferentially around the valve seat and axially inward from a side of the valve seat plate where the valve seat is located. The groove enables deformation in response to pressure differences across the valve seat plate in a manner that limits stress concentrations.

A fuel injector includes an injector housing having a nozzle assembly with a nozzle piece, and a nested check assembly of an outer check and an inner check. Spray orifices are formed in the nozzle piece in a first orifice set equipped with a first spray duct set and a second orifice set equipped with a second spray duct set. The inner check can be opened to spray fuel from the first orifice set and the outer check can be opened to spray fuel from both the first orifice set and the second orifice set. The outer check is non-rotating while the inner check can be permitted to rotate during service. Spray ducts associated with the first orifice set may have a different duct length and duct inside diameter than spray ducts associated with the second orifice set. The first orifice set may include lower-flow spray orifices and the second orifice set may include higher-flow spray orifices. Related methodology is also disclosed.

For a fuel injection device, a configuration to improve fuel sealability when a valve is closed is provided. Therefore, the fuel injection device includes: a valve body that opens and closes a fuel flow path; a movable iron core in which a fuel passage hole communicating an upstream side and a downstream side is formed, and that operates the valve body toward the upstream side; a biasing spring whose one end contacts the movable iron core, and that biases the movable iron core in a valve opening direction; and a regulating unit that regulates movement of the one end of the biasing spring, in which the shortest distance between the one end of the biasing spring and the fuel passage hole is larger than a radial travel distance of the one end until radial movement of the one end is regulated by the regulating unit.

For a fuel injection device, a configuration to improve fuel sealability when a valve is closed is provided. Therefore, the fuel injection device includes: a valve body that opens and closes a fuel flow path; a movable iron core in which a fuel passage hole communicating an upstream side and a downstream side is formed, and that operates the valve body toward the upstream side; a biasing spring whose one end contacts the movable iron core, and that biases the movable iron core in a valve opening direction; and a regulating unit that regulates movement of the one end of the biasing spring, in which the shortest distance between the one end of the biasing spring and the fuel passage hole is larger than a radial travel distance of the one end until radial movement of the one end is regulated by the regulating unit.

A fuel injector has means to directly inject one type of fuel or two types of fuels collectively with fuel ratios on demand. Once being used as a single fuel injector, the injector can enable injection rate shaping. Once being used as a dual fuel injector, the injector can tailor fuel properties on demand. The fuel injector has the capability to enable tailored chemical and thermal-physical fuel properties to enable high efficiency clean combustion for different engine loads and speeds.

A fuel injector includes an injector housing, an outlet check, an injection control valve assembly, and a valve seat orifice plate integrating a valve seat and various orifices for outlet check control. In the valve seat orifice plate a drain orifice extends between a valve seat surface and a check control chamber formed between a closing hydraulic surface of the outlet check and the valve seat orifice plate. First and second re-pressurization orifices extend between an outer surface of the valve seat orifice plate and the check control chamber.

A fuel injector includes an injector housing, an outlet check, an injection control valve assembly, and a valve seat orifice plate integrating a valve seat and various orifices for outlet check control. In the valve seat orifice plate a drain orifice extends between a valve seat surface and a check control chamber formed between a closing hydraulic surface of the outlet check and the valve seat orifice plate. First and second re-pressurization orifices extend between an outer surface of the valve seat orifice plate and the check control chamber.

A director plate retainer of a fluid injector includes an outer wall which is annular in shape and which extends from an outer wall first end to an outer wall second end and which is centered about an axis. The director plate retainer also includes a lateral wall which is annular in shape and which extends toward the axis from a radially outer extent, which is proximal to the outer wall, to a radially inner extent, which is distal from the outer wall. The director plate retainer also includes an inner wall which is annular in shape and which extends from an inner wall first end, which is proximal to the lateral wall, to an inner wall second end, which is distal from the lateral wall, the inner wall extending along the axis in a direction that is opposite from the outer wall.

A monolithic fuel rail structure is configured to receive and support a fuel injector, and includes a log, an injector cup that protrudes integrally from an outer surface of the log, and a fuel passage. An inner surface of the log defines a main fuel channel, and the injector cup includes a bore that opens at one end of the injector cup. An inlet end of the fuel injector is received in the bore. The fuel passage provides fluid communication between the bore and the main fuel channel, and the fuel passage corresponds to a portion of a hole that extends through the injector cup on each of opposed sides of the injector cup.

A monolithic fuel rail structure is configured to receive and support a fuel injector, and includes a log, an injector cup that protrudes integrally from an outer surface of the log, and a fuel passage. An inner surface of the log defines a main fuel channel, and the injector cup includes a bore that opens at one end of the injector cup. An inlet end of the fuel injector is received in the bore. The fuel passage provides fluid communication between the bore and the main fuel channel, and the fuel passage corresponds to a portion of a hole that extends through the injector cup on each of opposed sides of the injector cup.