DE102008040381A1 - High pressure resistant fuel injector - Google Patents

Abstract

A fuel injector for operating an internal combustion engine having an injector body (1; 1 ') in which an inlet bore (4), which has an oval cross-section, connects a pressure port (5) to a valve space (3) for supplying high-pressure fuel, wherein the valve space (3) is placed above a nozzle and a nozzle needle, wherein further the valve space (3) has a convexly curved in the radial direction, circumferential contour (6) into which the inlet bore (4) opens.

Description

The The invention relates to a fuel injector for operation an internal combustion engine with an injector, in which an inlet bore, which has an oval cross-section, a pressure port with a valve space for supply of high-pressure fuel connects, the valve space placed above a nozzle needle.

State of the art

From the DE 444 60 71 A1 a method for the production of high-pressure intersections is known, as can be used for example for the production of the pressure lines in an injector body of a fuel injector. In this case, an inlet bore to a valve chamber is designed to be oval in order to minimize stresses in the intersection region of the bore. By this measure, a better stress distribution in the inlet bore is achieved, which reduces the component load accordingly.

disadvantageous The known prior art is that the intersections in Range of transition of the inlet bore into the valve chamber still not optimally designed and thus the tensions in this area are too high.

It Therefore, the object of the present invention is a fuel injector to provide, wherein the inlet bore and the valve chamber in such a way are formed that in the area of transition between the two a reduction of the occurring voltages and thus a strength gain can be achieved.

Disclosure of the invention

These The object is based on the preamble of claim 1 in conjunction solved with its characterizing features. The following, dependent claims give each advantageous Further developments of the invention.

The Invention includes the technical teaching that the valve chamber a in the radial direction convexly curved, circumferential contour has, in which the inlet hole opens. By this arched shape of the valve chamber can be a reduction the notch effect in the area of bore intersection between valve space and inlet hole can be achieved.

advantageously, Here, the degree of convex curvature of the circumferential Contour formed such that the inlet bore opens orthogonally. By the measure, the strength in this area further increased and also the inflow characteristic of the high-pressure fuel can be improved.

According to one advantageous development of the invention, the inlet hole opens in the middle of the convexly curved contour in the radial direction of the valve space in this one. This has the advantage that the inflow characteristic in the valve chamber thereby further improved.

In Development of the invention opens the inlet hole the nozzle needle facing away from the half convex curved contour of the valve space in this one. Thereby it is possible to use the valve space inside the injector body to move closer to the area of the nozzle needle.

Corresponding a further embodiment of the invention opens a connecting line to the tip of the nozzle needle in the inlet bore in the area of a flat side of the oval cross section. This has the advantage that even in the area of an intersection of the connecting line With the inlet bore a strength gain is achieved.

In Further development of the invention is the inlet bore by means of milling, Eroding or electrochemical molding made. Through this Measure can be the oval cross section of Precision bore very precisely finished.

Further, The measures improving the invention will be described below together with the description of preferred embodiments of the invention with reference to the figures shown in more detail.

Brief description of the drawings

It shows:

1 a sectional view of the fuel injector according to the invention in half section according to a first embodiment of the invention; and

2 a detailed sectional view in the region of a valve chamber of the fuel injector according to the invention according to a second embodiment of the invention.

embodiments the invention

In 1 is a sectional view of a Injektorköpers 1 of the fuel injector according to the invention according to a first embodiment. In the lower part of this injector body 1 is a bore along the longitudinal center axis 2 arranged in which a nozzle and a nozzle needle is placed in the assembled state of the fuel injector. Above this hole 2 is also a valve chamber 3 formed, in which during operation of the internal combustion engine is under high pressure fuel, wherein the pressure prevailing here, an opening or closing of the nozzle needle is controlled during operation of the injector. The valve room 3 is on a radial side via an inlet bore 4 with a pressure connection 5 in connection, via which the high-pressure fuel is supplied to the fuel injector. The inlet bore 4 has an oval cross-section, which, however, does not emerge from this view. Furthermore, the inlet hole opens 4 on a convex, circumferential contour 6 of the valve chamber 3 preferably in a 90 ° angle in this one. By means of such a connection between the valve chamber 3 and inlet hole 4 the notch effect of the bore intersections is reduced, which is the high pressure resistance of the injector body 1 elevated. A connection line 7 which a connection between the inlet hole 4 and the nozzle and nozzle needle, not shown here produces, opens at a flat side of the oval of the inlet bore 4 in this one. The flat side of the oval here means the geometrically larger extension of the oval.

In 2 is a detailed sectional view of an injector body 1' see the fuel injector according to the invention according to a second embodiment. In contrast to the previously shown embodiment, the inlet bore opens 4 in this case not in the middle of the convex curvature of the circumferential contour 5 in the valve room 3 one, but something over the middle. Furthermore, no connection line is provided to the tip of the nozzle needle.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 4446071 A1 [0002]

Claims (6)

Fuel injector for the operation of an internal combustion engine with an injector body ( 1 ; 1' ), in which an inlet bore ( 4 ), which has an oval cross-section, a pressure port ( 5 ) with a valve space ( 3 ) connects to the supply of high-pressure fuel, wherein the valve space ( 3 ) is placed above a nozzle and a nozzle needle, characterized in that the valve space ( 3 ) a convexly curved in the radial direction, circumferential contour ( 6 ) into which the inlet bore ( 4 ). Fuel injector according to claim 1, characterized in that the degree of convex curvature of the circumferential contour ( 6 ) is designed such that the inlet bore ( 4 ) opens orthogonally. Fuel injector according to claim 1 or 2, characterized in that the inlet bore ( 4 ) in the middle of the convexly curved contour in the radial direction ( 6 ) of the valve space ( 3 ) opens into these, Fuel injector according to claim 1 or 2, characterized in that the inlet bore ( 4 ) on the side facing away from the nozzle half of the convexly curved contour ( 6 ) of the valve space ( 3 ) opens into this. Fuel injector according to one of claims 1-4, characterized in that a connecting line ( 7 ) to the tip of the nozzle and the nozzle needle into the inlet bore ( 4 ) opens in the region of a flat side of the oval cross-section. Fuel injector according to one of the preceding claims, characterized in that the inlet bore ( 4 ) is made by milling, eroding or electrochemical molding.