A nozzle assembly for a fuel injector includes a nozzle body and a needle tip positioned within the nozzle body. The needle check includes a terminal end surface positioned in spaced, facing relation to a sac surface of the nozzle body, to form a sac cavity. The terminal end surface and sac surface each have spherical shapes, and are centered about a longitudinal axis of the nozzle body. Structures of the terminal end surface and the sac surface are such that a clearance between them is nowhere less than along a line segment between centers of the terminal end surface and the sac surface, the sac cavity has a reduced volume, and wall thickness at the nozzle tip is sufficient for improved fracture resistance.

In some embodiments, the injector valves have additional flow holes in the seat face to reduce flow variation, decrease package size and allow for a fast response. In another embodiment, the injector valve has a seat with multiple flow channels leading to a venturi, allowing for a fast response and decreased package size.

A fuel injection valve includes a valve housing having an injection hole and a valve seat surface tapering toward a downstream side, a valve component that is accommodated in the valve housing and is coaxially separated from or seated on the valve seat surface, and an elastic component biasing the valve component toward the valve seat surface. The valve component includes an inner convex surface curved in a partial spherical shape with a predetermined curvature radius, and an outer convex surface that is provided continuously to the outer peripheral side of the inner convex surface and curved in a partial spherical shape having a smaller curvature radius than the inner convex surface. A boundary portion between the inner convex surface and the outer convex surface protrudes toward the valve seat surface so as to be able to be separated from or seated on the valve seat surface.

Provided is a fuel injector that is capable of reducing penetration. The fuel injector of the present invention includes a valve body having a valve body side seat surface, a valve seat side seat surface that abuts on the valve body side seat surface, and an injection hole that is provided downstream of a position at which the valve body side seat surface abuts on the valve seat side seat surface. The valve body has a projection that is formed from the valve body side seat surface toward the injection hole, and the projection is formed to be smaller in a direction of fuel flow between seats than a radius of an upstream opening surface of the injection hole.

Methods and systems are provided for direct fuel injection. In one example, a fuel injector system includes an injector needle with an injector pin with a curved fuel channel around the outer circumference of the injector pin, fluidically connected along the length of the curved fuel channel with a fuel reservoir inside the injector pin. An actuator coupled to the injector needle may sequentially move and position the injector needle to establish fluidic connection between the curved fuel channel and with one or more nozzle holes of the fuel injector at each position, discharging fuel from only those nozzle holes, thereby minimizing fuel spray interaction.

Methods and systems are provided for direct fuel injection. In one example, a fuel injector system includes an injector needle with an injector pin with a curved fuel channel around the outer circumference of the injector pin, fluidically connected along the length of the curved fuel channel with a fuel reservoir inside the injector pin. An actuator coupled to the injector needle may sequentially move and position the injector needle to establish fluidic connection between the curved fuel channel and with one or more nozzle holes of the fuel injector at each position, discharging fuel from only those nozzle holes, thereby minimizing fuel spray interaction.

In a fuel injection valve used in an internal combustion engine, fuel spray travel distance is shortened. There is provided a fuel injection valve including a seat member, in which the seat member includes a conical seat surface that seats fuel by coming in contact with a valve body, and inlet opening portions of a plurality of fuel injection holes on the conical seat surface, and is configured such that an axis of the injection hole connecting the centers of an inlet and an outlet of the fuel injection hole is along a plurality of different conical surfaces, and in which, in an outlet section that is configured of a plane parallel to an inlet section of the inlet opening portion of the fuel injection hole and is positioned at the outlet of the fuel injection hole, the seat member includes the injection hole in which a major axis direction of an ellipse of the outlet section has an inclination angle of greater than 0 degrees with respect to a straight line in a fuel injection direction, which is obtained by projecting the axis of the injection hole on the outlet section, and an inclination angle of a degree before being perpendicular to the straight line in the fuel injection direction.

In some embodiments, the injector valves have additional flow holes in the seat face to reduce flow variation, decrease package size and allow for a fast response. In another embodiment, the injector valve has a seat with multiple flow channels leading to a venturi, allowing for a fast response and decreased package size.