A fluid injector for injecting fluid is disclosed, including a body, a fluid passageway defined through the body and extending from an inlet to an outlet of the fluid injector; a valve seat disposed internally of the body and forming part of the passageway; and a valve element that is selectively reciprocated relative to the valve seat to close and open the passageway to the flow of fluid by seating and unseating the valve element on and from the valve seat, respectively. The fluid injector further includes an orifice disc disposed in the passageway downstream of the valve seat in a direction of the flow of fluid through the fluid injector. The orifice disc includes a plurality of dimples and a plurality of orifices defined through the orifice disc, with each dimple including at least one orifice defined therethrough.

A valve (or fuel injector), which provides that the valve-seat member exhibits high structural strength and fatigue strength under vibratory stresses, includes an excitable actuator for actuating a valve-closing member which, with a valve-seat face on the valve-seat member, forms a sealing seat, and injection openings which are downstream of the valve-seat face, the injection openings being in a center area of the valve-seat member projecting outwardly dome-like in the injection direction. The dome-like center area has a curved outer contour, the curvature in a radially inner section having a larger radius than the radius of the curvature in a radially outer section of the dome, which ends radially outside the mouth areas of all injection openings, in a recessed depression, that is followed radially outwardly by an axially projecting edge area of the valve-seat member. The fuel injector directly injects fuel into a combustion chamber of an engine.

This fuel injection valve is provided with a needle having a valve body (27c) and a rod part (27b) of which one end is bonded by welding to the valve body (27c). A contact portion (81) between the rod part (27b) and the valve body (27c) is disposed nearer to a valve shaft center (27x) than is a weld-penetration portion (80) created by the weld-bonding of the rod part (27b) and the valve body (27c), and a non-welded portion (82) is provided between the contact portion (81) and the weld-penetration portion (80).

The present invention is directed to achieving an appropriate L/D of each injection hole in a fuel injection device in which a plurality of injection holes is formed. To achieve the object, provided is a fuel injection device including a valve body and an injection hole forming portion in which a plurality of injection holes is formed on a more downstream side than a seat portion on which the valve body is seated, in which the injection hole forming portion is formed in a manner such that a valve body central axis and a central axis of the injection hole forming portion are horizontally deviated in a vertical cross-sectional surface passing through the valve body central axis.

An assembly for a fuel injector includes a base material, a coated region formed on a surface of the base material, an uncoated region formed on a surface of the base material, in contact with and supported by a jig, and formed to be partitioned from the coated region so as to prevent the coated region from peeling off during laser welding, and a coating material stacked in a multilayer structure on the coated region. As a result, friction reduction, high hardness, impact resistance, heat resistance, and durability of the assembly may be improved, and a portion requiring the coating may be precisely coated.

Methods and systems are provided for a fuel injector. In one example, a system may include forming an annular venturi passage between an outlet surface of the fuel injector and a nozzle. The nozzle may further comprise one or more air entraining features that may work in concert with the annular venturi passage to promote air-fuel mixing.

A fluid injector includes a fluid inlet; a valve seat located downstream of the fluid inlet and having a valve seat aperture extending therethrough; a valve member moveable between a closed position and an open position to control flow through the valve seat aperture; and director plate including a first aperture and a second aperture extending therethrough. A fluid flow channel is formed between the valve seat and the director plate and extends from an inlet end to an outlet end. The first aperture and the second aperture extend through the director plate from the fluid flow channel. The first aperture is located between the inlet end and the second aperture. The fluid flow channel decreases in cross-sectional area from the inlet end toward the first aperture and the fluid flow channel increases in cross-sectional area from the first aperture toward the second aperture.

Methods and systems are provided for a fuel injector. In one example, a system may include forming an annular venturi passage between an outlet surface of the fuel injector and a nozzle. The nozzle may further comprise one or more air entraining features that may work in concert with the annular venturi passage to promote air-fuel mixing.

Recent exhaust gas regulation requires reduction of an amount and quantity of particulate matter included in an exhaust gas, and a normal maximum fuel pressure may be increased to approximately 35 MP. When the normal maximum fuel pressure is 35 MPa, a fuel injection valve is required to work for example at a pressure up to 45 MPa. In such a condition, a fluid force may exceed a valve opening force depending on a seat diameter, and a needle valve cannot be kept open and closed, when opening thereof is required. In order to solve the above problems, a fuel injection valve according to the present invention includes a valve seat portion, a valve body which is seated on or separated from the valve seat portion, an injection hole which is formed on a downstream side from the valve seat portion, and a guide portion which is formed on an upstream side from the valve seat portion seating a valve body seat portion of the valve body to guide a guided portion on a downstream side of the valve body, in which the valve seat portion is formed to have a dimension in a crossing direction crossing an axial direction of 0.4 to 0.8 times a dimension of the guide portion in the crossing direction.

An injection hole body has multiple injection holes for injecting fuel. A valve body is unseated from and seated on a seating surface of the injection hole body. The injection hole body and the valve body form a specific space therebetween to communicate with inflow ports of the injection holes. A virtual region is surrounded by multiple straight lines. The straight lines connect portions of peripheral edges of the inflow ports, which are closest to a center axis of the valve body in the radial direction. A center volume is formed by extending the virtual region from the injection hole body toward the valve body along the center axis. A total injection hole volume is a total volume of the injection holes. The total injection hole volume is larger than the center volume in a state where the valve body is seated on the seating surface.