Fuel injection valve

#The present invention is directed to a fuel injector according to the preamble of the main claim.

#An electromagnetically actuatable fuel injector is known from German Patent 39 43 005 in which multiple disk-shaped elements are situated in the seat area. When the magnetic circuit is energized, a flat valve plate acting as a flat armature is lifted up from a valve seat plate situated at the opposite end which cooperates with the flat valve plate and together with the flat valve plate forms a plate valve part. A swirl element is situated upstream from the valve seat plate which imparts a circular rotational motion to the fuel flowing to the valve seat. A stop plate delimits the axial path of the valve plate at the opposite end from the valve seat plate. The valve plate is enclosed by the swirl element with a large amount of play; the swirl element thus takes over a certain guiding of the valve plate. Multiple tangentially running grooves are provided in the swirl element on its lower front face which extend from the outer periphery into a center swirl chamber. When the swirl element rests with its lower front face on the valve seat plate, the grooves act as swirl channels. The spray-discharge orifice provided in the valve seat plate determines the spray-discharge geometry via its length and diameter, and therefore must be introduced with great precision.

#In addition, a fuel injector is known from Unexamined European Patent Application 350 885 in which a valve seat body is provided, a valve closing body which is situated on an axially movable valve needle cooperating with a valve seat face of the valve seat body. In a recess in the valve seat body upstream from the valve seat face a swirl element is situated which imparts a circular rotational motion to the fuel flowing to the valve seat. A stop plate delimits the axial path of the valve needle and has a central orifice which provides a certain guiding of the valve needle. Multiple tangentially running grooves are provided in the swirl element on its lower front face which extend from the outer periphery into a center swirl chamber. When the swirl element rests with its lower front face on the valve seat body, the grooves act as swirl channels. In this fuel injector as well, the size of the spray-discharge orifice provided in the valve seat body determines the spray-discharge geometry, so that this spray-discharge orifice must also be shaped very precisely.

#Exemplary embodiments of the present invention are illustrated in a simplified manner in the drawing and explained in more detail in the following description.

#FIG. 1 shows a first embodiment of a fuel injector,

#FIG. 2 shows a second embodiment of a fuel injector, and

#The valve, which is illustrated as an exemplary embodiment in FIG. 1 as an electromagnetically actuatable injector for fuel injection systems in spark ignition internal combustion engines, has a tubular, substantially hollow cylindrical core 2 which is at least partially enclosed by a solenoid 1 and which acts as an internal pole of a magnetic circuit. The fuel injector is particularly suitable as a high-pressure injector for direct spray discharge of fuel into a combustion chamber of an internal combustion engine. A bobbin 3 made of plastic, which has a stepped design, for example, accommodates a winding of solenoid 1 and, in conjunction with core 2 and an annular, nonmagnetic intermediate part 4 having an L-shaped cross section which is partially enclosed by solenoid 1, allows a particularly compact and short design of the injector in the region of solenoid 1.

#A pass-through longitudinal orifice 7 is provided in core 2 which extends along a longitudinal valve axis 8. Core 2 of the magnetic circuit also serves as a fuel inlet connector, longitudinal orifice 7 representing a fuel supply duct. Above solenoid 1, core 2 is firmly attached to outer metallic (ferritic, for example) housing part 14, which as a stationary pole or external guide element closes the magnetic circuit and completely encloses solenoid 1, at least in the circumferential direction. A fuel filter 15 is provided on the inflow side in longitudinal orifice 7 of core 2 for filtering out fuel components which because of their size could cause blockage or damage in the injector. Fuel filter 15 is attached by pressing it into core 2, for example.

#Core 2 together with housing part 14 forms the inflow-side end of the fuel injector, upper housing part 14 extending just over solenoid 1 as seen downstream in the axial direction, for example. A lower tubular housing part 18 is tightly and permanently joined to upper housing part 14 and encloses or accommodates for example an axially movable valve part having an armature 19, a rod-shaped valve needle 20, and an elongated valve seat support 21. Both housing parts 14 and 18 are permanently joined together by a circumferential weld, for example.