Among all combinations of two injection holes, in a combination in which when the injection holes are offset such that their central axes are coincident with each other in inlet openings, an inter-injection hole angle formed by the central axes is minimized, the inter-injection hole angle between the two injection holes is represented as yamin[deg], taper angles, which are formed by the respective contours of the injection hole inner walls in the cross sections along the virtual planes including the central axes of the two injection holes that allow the inter-injection hole angle to be minimized, are represented as a1 and a2[deg], and when fuel is injected from the injection holes, average pressure of the fuel in the fuel passage is represented as P[Mpa], and the injection holes are formed so as to satisfy a relationship: amina1+a2+0.5P.sup.0.6.

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.

An injector for injecting a fluid includes a base body having an opening and a sealing seat, a spray-orifice disk having at least one spray orifice, and a clamping ring, the spray-orifice disk being disposed in the opening of the base body, and a first nonpositive connection is provided between the spray-orifice disk and the base body, and a second nonpositive connection is provided between the base body and the clamping ring.

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.

Among all combinations of two injection holes, in a combination in which when the injection holes are offset such that their central axes are coincident with each other in inlet openings, an inter-injection hole angle formed by the central axes is minimized, the inter-injection hole angle between the two injection holes is represented as a min[deg], taper angles, which are formed by the respective contours of the injection hole inner walls in the cross sections along the virtual planes including the central axes of the two injection holes that allow the inter-injection hole angle to be minimized, are represented as a1 and a2[deg], and when fuel is injected from the injection holes, average pressure of the fuel in the fuel passage is represented as P[Mpa], and the injection holes are formed so as to satisfy a relationship: a mina1+a2+0.5P.sup.0.6.

A first spring axially urges a needle valve toward an injection hole. A second spring axially urges a movable core toward a stationary core with an urging force that is smaller than an urging force of the first spring. A stopper is placed on one axial side of the movable core where the injection hole is located. The stopper limits movement of the movable core toward the injection hole to limit an amount of compression of the second spring.

A fuel and gas mixing structure for an engine is provided. This mixing structure includes a body configured to be positioned between a fuel injector and a cylinder of an engine. The body defines an interior volume that is configured to receive gas from outside the body and to receive one or more streams of fuel from the fuel injector in the interior volume. The body also defines one or more mixture conduits configured to conduct plumes of the fuel and gas, while mixing, from the interior volume to one or more exit ports and therethrough to the cylinder.

In a nozzle plate, a portion of fuel flowing out from a fuel injection port of the fuel injection device is atomized by impinging on an interference body. At the same time, the flow of the portion of fuel is sharply bent and impinges on fuel which straightly advances and passes through a nozzle hole and an orifice thus turning the flow of fuel into a turbulent flow. Further, both end portions of the orifice form non-rounded sharpened corner portions. Hence, a liquid film of fuel injected from the corner portions and areas in the vicinity of the corner portions of the orifice is formed into a thin sharpened and pointed state whereby an end portion of the liquid film of fuel injected from the orifice is easily atomized due to a friction between the end portion of the liquid film of fuel and air.

Provided is a structure capable of reducing dribbling of fuel generated when a valve body is closed. In order to achieve the above object, a fuel injection device includes: a valve body; and a seat member having a seat portion on which the valve body is seated and having a fuel injection hole formed on a downstream side of the seat portion. The seat member is formed such that a gap between the seat member and the opposing valve body in the whole region on the downstream side of the fuel injection hole is smaller than a diameter of the fuel injection hole.

In a nozzle plate of the present invention, a part of fuel flowing out from a fuel injection port of a fuel injection device is atomized by colliding with an interference body, is rapidly bent in a flowing direction, and collides with the fuel that is flowing straight through a nozzle hole and an orifice to make the fuel that flows straight through the nozzle hole and the orifice turbulent. The orifice includes a corner portion which is defined by an outer edge portion of the interference body and has a pointed shape without roundness at a part of an opening edge. The corner portion makes an end portion of a liquid film of the fuel passing through the orifice into a pointed shape for ease of atomization by friction with air.