EP1291519A2 - Injector body with tangential pressure port - Google Patents

Abstract

The fuel injector, for an internal combustion motor, has an injector body (1) with an inner ring zone (5) where a fuel feed drilling (10) has its opening (12). A pressure tube connection (7) is at the injector body, with a sealing surface (9). The pressure tube connection is offset from the symmetry line of the ring zone, so that the feed drilling in the connection opens into the ring zone at a tangent with an obtuse entry angle.

Description

Technical field

Today, fuel injection systems are increasingly used in direct-injection internal combustion engines with high-pressure manifold (common rail). Through a High-pressure collection chamber permanently pressurized high-pressure pump in this one maintain an almost constant, high pressure level. The one in the high-pressure collection room fuel stored at a high pressure level is forwarded to the fuel injectors, each assigned to the individual combustion chambers of the internal combustion engine are. To the fuel injectors, the supply lines from the high-pressure manifold as well as their connections and the feed system within the injector body are therefore to make increased demands with regard to high pressure resistance.

State of the art

DE 196 50 865 A1 relates to a solenoid valve for controlling a fuel injection valve. A solenoid valve is proposed, the armature of which consists of several parts is formed and has an armature disk and an anchor bolt, which in one Slider is guided. To prevent the armature disc from swinging after closing the To avoid solenoid valves, a damping device is provided on the magnet armature. With such a device, the required short switching times of the solenoid valve are exactly observable and can be reproduced in operation. The solenoid valve is determined for use in injection systems with a high-pressure manifold (common rail).

According to this solution there is a connection for a supply line from the high-pressure plenum added to the valve body at an angle, which means an improvement the high pressure resistance of a fuel injector can be achieved. The one with this measure achievable improvement in high-pressure strength is still unsatisfactory, however with a view to a further increase in the pressure level in the high-pressure plenum (Common-Rail) the high-pressure strength gain achieved in the course of this measure the progressive development should be consumed.

Presentation of the invention

With the solution according to the invention, compared to known solutions, the strength eliminate the weak point in the injector body that determines the injector body. The The intersection of the inlet bore and the ring channel is due to that in the injector body prevailing internal pressure and static installation / assembly forces, highest mechanical Exposed to stresses due to an inclined positioning of the inlet bore or their eccentric entry into the ring channel within the injector body considerably can be reduced. In addition to the load on the injector body the internal pressure in the ring channel is the inlet bore in the pipe connection mechanical stress due to the introduction of force at the screwing point of the High pressure supply line exposed from the high pressure manifold. The introduction of the bolting forces in the area of the pipe socket causes its radial expansion in the Threaded portion; the internal pressure load is superimposed on this mechanical load, which is generated by the inflowing fuel under very high pressure from the high-pressure manifold (common rail) into the annulus of the injector body flows through the inlet bore. The solution according to the invention sees a swivel the pressure pipe socket and consequently the inlet bore received therein; With an offset or pivoted arrangement of the pressure pipe socket relative to the axis of symmetry of the annulus is due to a right angle, d. H. vertical course the inlet bore from the sealing surface of the pressure pipe socket, whose internal thread is connected downstream is to maintain the strength while the mechanical stresses on the strength-related weak point, d. H. the transition of the mouth of the inlet bore can be significantly reduced in the ring channel.

The pivoting of the pressure connection geometry or its offset relative to the axis of symmetry of the ring channel in an inflow position in the center relative to the axis of symmetry of the injector body can be achieved by a simple modification of the forged blank of the injector body can be implemented without additional manufacturing technology performing measures are necessary. Can according to one of the variants of the present invention particularly obtuse inlet angle of the inlet bore into the annular space achieved in the injector body, the strength gain is considerable. The duller the inlet angle of the inlet bore can be formed, the higher the gain in strength results on the injector body.

drawing

The invention is explained in more detail below with the aid of the drawing.

Figur 1, 2

eine aus dem Stand der Technik bekannte Injektorausführung in Längsund Querschnittdarstellung,

Figur 3

eine im Druckrohrstutzen eines Injektorkörpers verschwenkt aufgenommene Zulaufbohrung,

Figur 4

einen am Injektorkörper zu dessen Symmetrieachse versetzt angeordneten Druckrohrstutzen und

Figur 5

einen am Injektorkörper in geschwenkter Lage angeordneten Druckrohrstutzen.

It shows:

Figure 1, 2nd

a longitudinal and cross-sectional injector design known from the prior art,

Figure 3

an inlet bore pivoted in the pressure pipe socket of an injector body,

Figure 4

a pressure pipe socket arranged on the injector body offset to its axis of symmetry and

Figure 5

a pressure pipe socket arranged on the injector body in a pivoted position.

variants

1 shows a series-produced injector body known from the prior art of a fuel injector in longitudinal section.

The sectional view according to FIG. 1 shows an injector body 1, in the upper one Area an external thread 2 is added. On the external thread 2 is one here Magnetic sleeve, not shown, attached, which surrounds an electromagnet, which with which an actuating element, not shown here, also relieves pressure Control room, not shown, can be actuated. There is an installation space 3 in the injector body 1 intended for the electromagnet by screwing a magnetic sleeve to the external thread 2 is attached to the injector body 1. Below the installation space 3 for recording of the solenoid valve, an installation space 4 is provided, which is also not shown accommodates anchor arrangement configured in one or more parts. Below the installation space 4 shows an annular space 5, which is under extremely high pressure Fuel is applied. Below the annular space 5 closes in the injector body 1, a guide section 6 for one in the illustration according to FIG. 1 likewise Tappet / nozzle needle arrangement, not shown. On the side of the injector body 1 is a Pressure pipe socket 7 added, which can be provided with an internal thread 8. In this can be screwed into a connector of a high pressure line, via which the injector body 1 of the fuel injector for injecting fuel into the Combustion chamber of an internal combustion engine with a feed line from the high-pressure collection chamber (Common Rail) is connected.

The fuel stored in the high-pressure manifold (common rail) is fed through a High pressure pump kept at a constant high pressure level, from the high pressure plenum (Common rail) the individual fuel injectors in injection sequence the internal combustion engine can be pressurized with fuel under high pressure are. Due to the high prevailing in the common rail Pressure, pressure pulsations in pressure fluctuations in the fuel are compensated for, so that on the individual, the combustion chambers of the internal combustion engine assigned A constant injection pressure is permanently present.

An inlet bore 10 runs from the sealing surface 9 in the pressure pipe socket 7 in the direction on the annular space 5 in the injector body 1, which in the annular space 5 at an outlet point 12 flows. 1 shows that the inlet bore 10 at an angle 13, in the present case an acute angle 13, from the sealing surface 9 branches off and at an also acute angle 14 with respect to the axis of symmetry of the annular space 5 opens into the annular space 5. With reference numeral 11 is the angle of inclination the sealing surface 9 formed in the pressure pipe socket 7 with respect to the axis of symmetry of the annulus 5 identified.

FIG. 2 shows a cross section through the injector body as shown in FIG. 1 according to the section line II-II.

From the cross-sectional view of the injector body 1 according to FIG. 2 it can be seen that the Inlet bore 10 extends in a length 23 from the sealing surface 9 of the pressure pipe socket 7 to extends to the wall of the annular space 5. In addition to the inclination shown in FIG. 1 in relation to the longitudinal axis through the angle 13, the inlet bore 10 runs Sealing surface 9 inclined by an angle of inclination 21 in the direction of the annular space 5. Im Annulus 5 essentially opens the inlet bore 10 at an outlet point 12 one in the running angle 22, which, as shown in FIG. 2, is referred to as the right angle is. The inlet bore 10 thus opens approximately centrally in the annular space 5, which in the Area of the mouth 12 an area of reduced high pressure resistance due to selected mouth location results. In particular, the sharp-edged corners of the Inlet bore 10 in the area of the mouth 12 are due to the occurring Pressure loads exposed to the highest mechanical stresses. Regarding the The line of symmetry 24 of the pressure port 7 runs the inlet bore 10 as shown 2 in an inclined position 25 with respect to the line of symmetry 24.

Fig. 3 shows a in the pressure pipe socket of an injector body in relation to the one to be acted upon Annulus tangentially extending inlet bore 10.

3 that the inlet bore 10 is no longer in the middle (cf. illustration according to FIG. 2) opens into the annular space 5, but rather that the opening point 12 of the inlet bore 10 opens tangentially into the annular space 5. The slant the inlet bore 10 in the injector body 1 is characterized by the angle 25. According to the illustration in FIG. 3, there is a point in the area of the sealing surface 9 Angle 21 between the orientation of the sealing surface 9 in the pressure pipe socket 7 and the channel cross section of the inlet bore 10, which indicates a potential weak or Leak can represent.

Fig. 4 shows an offset on the injector body to its axis of symmetry An inlet connector.

4 that the pressure pipe socket 7 with respect to the annular space 5 formed in the injector body 1 is offset. The staggered arrangement of the pressure pipe socket 7 can be done by simple measures in the manufacture of the forging blank of the injector body 1 are implemented, so that there is an offset 30 between the line of symmetry of the pressure pipe socket 7 and the perpendicular to the plane of the drawing Axis of symmetry of the annular space 5 in the injector body 1. In the illustration 4, the line of symmetry 33 of the inlet bore 10 and the line of symmetry fall the pressure pipe socket 7 together. In contrast to those shown in Fig. 1 to 3 Inlet bores 10 branches the inlet point of the inlet bore 10 in the sealing surface 9 in a right angle 38, i.e. H. perpendicular to the flat sealing surface 9. This on the one hand facilitates a seal at the transition point from the one not shown here High pressure supply line to the pressure pipe socket 7 and on the other hand sets the mechanical Stresses to an absolute minimum. The inlet bore 10 runs parallel to the axis of symmetry in the representation of the injector body 1 according to FIG. 4 of the pressure pipe socket and opens into the wall of the annular space 5 at the mouth 12 in a first obtuse entry angle 31. Through the tangential into the annulus 5 of the injector body 1 opening inlet bore 10, the mechanical load significantly reduced at the mouth 12 of the inlet bore in the annular space 5. Furthermore, the acute angle 21 shown in FIG. 3 is at which the angle shown there Inlet bore 10 branches off from the sealing surface 9, omitted. On the one hand, this means that Manufacture of the inlet bore 10 in the injector body 1 considerably simplified, on the other hand can be by the arrangement shown in Fig. 4, in the inlet area of the inlet bore 10 prevailing mechanical stresses due to the under high Reduce the pressure of fuel shooting into the inlet bore 10 considerably.

Another embodiment variant of the solution proposed according to the invention is the 5, the one on the injector body in a pivoted position arranged pressure pipe socket shows.

The pivoted arrangement of the pressure pipe socket 7 in relation to the injector body 1 is designated by reference numeral 34. The inlet bore also runs according to this arrangement 10 with respect to the sealing surface 9 of the pressure pipe socket 7 perpendicular to this in Direction to the annular space 5 of the injector body 1. The inlet angle at the mouth 12 is designated by reference numeral 35, with the embodiment variant according to FIG Fig. 5 is a second obtuse inlet angle 35. In comparison to the variant 4 is the length of the inlet bore 10 between the sealing surface 9 and the mouth 12 much shorter. Analogous to the first variant 4, the axis of symmetry 33 of the inlet bore 10 and that of the pressure pipe socket fall 7 together. The inclination to the pressure pipe socket 7 or inlet bore 10 is in the second embodiment variant according to FIG. 5 due to the inclination angle 36, which is the angular offset between the line of symmetry 33 of inlet bore 10 and pressure pipe socket 7 and the horizontal with respect to the Annulus 5 of the injector body 1 denotes. The pressure pipe socket 7, which in the second 5 is pivoted relative to the injector body 1, can also take up an internal thread 8, on which a not shown here from High-pressure plenum screwed from the high-pressure line leading to the injector body 1 can be. By avoiding an acute angle 21 between the entry point in the inlet bore 10 and the sealing surface 9 can due to the flatness of the Areas sufficient sealing effect can be achieved while the achievable enema 35 of the inlet bore 10 tangentially into the wall of the annular space 5 from the Choice of the inclination angle 36 is dependent. The more obtuse the inlet angle 31 or 35 in the annular space 5 can be selected within the injector body 1, one more more favorable mechanical stress on the injector body 1, the wall with reference numerals 37 is identified, arises.

The formation of an essentially obtuse entry angle 31 or 35 according to FIG Variants in Fig. 4 and Fig. 5 allows a much more favorable voltage distribution in the wall 37 of the injector body 1 delimiting the annular space 5 Strength reserve represents a safety aspect on the one hand and has a favorable effect the service life of a fuel injector according to the invention, on the other hand is due to the selected configuration of the pressure pipe socket 7 in relation to the inlet angle in the annulus 5 a strength potential is available, which is another Use of an injector body 1 configured according to the invention with increasing Pressure levels in the high-pressure plenum (common rail) of a fuel injection system for an internal combustion engine.

LIST OF REFERENCE NUMBERS

1

injector

2

connecting thread

3

Space for solenoid valve

4

Installation space anchor arrangement

5

annular channel

6

Nozzle needle / tappet guide

7

An inlet connector

8th

inner thread

9

sealing surface

10

inlet bore

11

Tilt angle sealing surface

12

Mouth point inlet bore annulus

13

acute angle inlet inlet bore

14

Opening sites angle

20

Circumferential position of the mouth

21

Tilt angle sealing surface

22

right angle mouth

23

Length of inlet bore

24

Symmetry line pressure pipe socket

25

banking

30

Offset pressure pipe socket injector body

31

first obtuse entry angle

32

Location of inlet hole

33

Axis of symmetry inlet bore

34

pivoted pressure pipe socket

35

second obtuse entry angle

36

inclination

37

Wall of injector body

38

right angle

Claims (6)

Fuel injector for injecting fuel into the combustion chamber of an internal combustion engine, comprising an injector body (1), in which an annular space (5) is formed, into which an inlet bore (10) opens at an outlet point (12) and enters the injector body (1) Pressure pipe socket (7) is formed with a sealing surface (9), characterized in that the pressure pipe socket (7) is arranged offset to the line of symmetry of the annular space (5) and the inlet bore (10) made in the pressure pipe socket (7) is tangential at an obtuse inlet angle ( 31, 35) in the annular space (5) at the mouth (12). Fuel injector according to claim 1, characterized in that the inlet bore (10) in the pressure pipe socket (7) extends perpendicularly from the sealing surface (9) to the annular space (5). Fuel injector according to claim 1, characterized in that the pressure pipe socket (7) is arranged in a lateral offset (30) to the axis of symmetry of the annular space (5). Fuel injector according to claim 3, characterized in that the axis of symmetry (33) of the inlet bore (10) coincides with the axis of symmetry of the pressure pipe socket (7) and the inlet bore (10) opens into a first obtuse inlet angle (31) in the annular space (5). Fuel injector according to claim 1, characterized in that the pressure pipe socket (7) on the injector body (1) is received pivoted by an inclination angle (36). Fuel injector according to claim 5, characterized in that the inlet bore (10) opens tangentially in the pivoted pressure pipe socket (7) in a second obtuse inlet angle (35) in the annular space (5) of the injector body (1).

Images