A fuel injection control device is adapted for a fuel injection system including an injector and a high-pressure pump that raises pressure of fuel and supplies the fuel to the injector. The fuel injection control device includes a selecting unit for selecting by which one of full lift injection and partial injection to inject fuel, and a pump control unit for controlling operation of the high-pressure pump such that a pressure of fuel supplied to the injector coincides with a target pressure. The selecting unit selects the partial injection when a required injection quantity of fuel is equal to or smaller than a partial maximum injection quantity. A fuel injection system includes the fuel injection control device, the injector, and the high-pressure pump.

Injection holes of an injection nozzle are respectively formed such that an inner diameter of an outer opening is larger than an inner diameter of an inner opening. Furthermore, the injection holes are formed such that when an imaginary plane, which includes a valve seat portion that is a portion of a valve seat and is adjacent to the injection hole, is extended toward a central axis, the imaginary plane first intersects with an injection hole inner wall portion of an injection hole inner wall of the injection hole.

Injection holes of an injection nozzle are respectively formed such that an inner diameter of an outer opening is larger than an inner diameter of an inner opening. Furthermore, the injection holes are formed such that when an imaginary plane, which includes a valve seat portion that is a portion of a valve seat and is adjacent to the injection hole, is extended toward a central axis, the imaginary plane first intersects with an injection hole inner wall portion of an injection hole inner wall of the injection hole.

Various methods and systems are provided for a combustion system of an engine. In one example, a combustion system comprises a piston crown bowl with a central apex, a combustion chamber operable at a compression ratio in a range of from about 13:1 to about 17:1, the combustion chamber formed at least partially by the piston crown bowl, and a fuel injector with a nozzle extending into a central portion of the combustion chamber that is operable to inject fuel directly into the combustion chamber, the nozzle defining a number of apertures that is in a range of from six to ten.

The present invention is a compression-ignition direct-injection internal-combustion engine comprising at least a cylinder, a cylinder head carrying fuel injection, a piston sliding in the cylinder, a combustion chamber limited on one side by upper face of the piston comprising a projection extending in the direction of the cylinder head and in the center of a concave bowl (46) with at least two mixing zones. The fuel injection projects fuel in at least two fuel jet sheets with different sheet angles, with a lower sheet having a jet axis C1 for one zone and an upper sheet having a jet axis for the other zone.

The injection feeds fuel into the combustion chamber with a different flow rate for each sheet for dedicated targeting in the mixing zones of the combustion chamber.

A Laval shape is formed between the nozzle seat surface and needle tip portion. An injection hole also has the Laval shape. When the needle lift amount is small, a fuel flow velocity reaches an acoustic velocity in valve-opening portion. The fuel flow velocity further accelerated to a supersonic velocity at the Laval shape. When the needle lift amount is large, the fuel flows into the injection hole without a velocity decrease. Thus, the fuel flow velocity reaches the supersonic velocity at the Laval shape.

In a fuel injection valve, it is possible to obtain spray in which the penetrating force of injected fuel is suppressed. The fuel injection valve includes a valve seat that forms a gap with a valve body, the gap allowing fuel to pass therethrough, and multiple injection holes that are located further downstream from the gap. The fuel to which pressure is applied flows out from the injection holes. When the flow velocity of the fuel in the gap formed between the valve body and the valve seat is indicated by meters per second, the flow velocity is set to be greater than a value obtained by multiplying the square root of the pressure applied to the fuel by 28. In this manner, the flow velocity in the gap increases, and flow velocity distribution inside the injection hole is uniformized, thereby suppressing an increase in penetration.

A process for manufacturing an injector body includes a) machining a metal blank to desired outer dimensions of the injector body; b) machining the metal blank along a first axis to define a spray hole within the metal blank; and c) machining the metal blank along a second axis to define an internal cavity in fluid communication with the spray hole.

An object of the present invention is to improve the exhaust emission for a fuel injection valve having a stepped injection hole constructed so that a small diameter portion and a large diameter portion are communicated with each other with a stepped portion intervening therebetween. The present invention resides in a fuel injection valve comprising a cylindrical nozzle body which has a tip portion formed to have a conical shape, an injection hole which penetrates from an inner circumferential surface to an outer circumferential surface of the nozzle body, the injection hole being constructed so that a small diameter portion, which is positioned on a side of the inner circumferential surface of the nozzle body, is communicated with a large diameter portion which is positioned on a side of the outer circumferential surface of the nozzle body, with a stepped portion intervening therebetween, and a valve plug which is accommodated slidably in the nozzle body and which opens/closes the injection hole, wherein a ratio of the hole diameter of the large diameter portion with respect to the hole diameter of the small diameter portion is not less than 3.1 and not more than 4.0, a ratio of a length of the large diameter portion with respect to a length of the small diameter portion is not less than 0.25 and not more than 0.55, and a ratio of the length of the large diameter portion with respect to the hole diameter of the large diameter portion is not less than 0.4 and not more than 1.6.

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.