EP1599669B1 - Fuel injection valve - Google Patents

Description

State of the art

The invention relates to a fuel injection valve according to the preamble of the main claim.

For example, is from the DE 196 25 059 A1 a fuel injection valve for directly injecting fuel into a mixture-compression, spark-ignition internal combustion engine, which provides a flow path for the fuel from a fuel inlet to a spray orifice, in which a plurality of fuel channels is arranged in front of the injection orifice whose cross section for a given fuel pressure injected per unit time Fuel quantity determined. In order to influence the fuel distribution in an injected mixture cloud and in particular to achieve a targeted strandiness of the mixture cloud, it is provided that at least a part of the fuel channels is aligned so that the fuel jets emerging from these are sprayed directly through the spray opening with open fuel injection valve.

A disadvantage of the fuel injection valve known from the above-mentioned document in particular the limited intervention options in the formation of the Mixture cloud. Apart from a variation of the beam expansion and the orientation of the center of gravity of the mixture cloud, it is hardly possible to influence deviations from the conical shape in the form of irregular mixture clouds and heterogeneously distributed beam penetration. Accordingly, the possibilities for reducing fuel consumption or exhaust emission are low.

The DE 101 18 163 A1 discloses a multi-hole fuel injection valve in which the injection orifices are mounted so that the mixture flows circulating in the combustion chamber are shielded from the injection orifices of the multi-hole fuel injection valve and thereby no fuel can settle in the region of the injection openings. To achieve this, the ejection openings are surrounded in one embodiment at the end face of the valve seat body by a ring wall and in another embodiment, the same effect is achieved by lowering the outlets, so that the injection orifices relative to the end face of the valve seat body are reset.

Advantages of the invention

The inventive method for operating a fuel injection valve having the characterizing features of the main claim has the advantage that a mixture cloud with high Zerstäubungsgüte can be generated by a high fuel pressure in the fuel distribution line for a spray-guided combustion process, without the disadvantages occurring in fuel injection valves with swirl insert disadvantages such as high fuel consumption . Coking of the valve tip or increased exhaust emissions to accept.

The injection openings open into extensions, which advantageously provide effective coking protection in the mouth region of the injection openings.

By means of a defined ratio of the total length 1 or the reduced length 1 'on the inflow side of the extensions and of the diameter d of the spray-discharge openings 1: d, it can be ensured that optimum jet conditioning is possible.

The measures listed in the dependent claims advantageous refinements of the fuel injection valve specified in the main claim are possible.

Advantageously, the at least two ejection openings can be mounted in any desired manner in the valve seat body, for. On concentric or eccentric bolt circles or ellipses or on straight or curved rows.

In addition, the centers of the injection orifices can be equidistant or spaced differently from each other, as well as the orientation of the axes of the injection orifices may be arbitrary.

Advantageously, none of the spray openings is directed to the spark plug, so that a coking of the spark gap and a shortened life can be avoided.

drawing

Fig. 1

einen schematischen Schnitt durch ein Ausführungsbeispiel eines erfindungsgemäß ausgestalteten Brennstoffeinspritzventils in einer Gesamtansicht,

Fig. 2

einen Ausschnitt aus dem in Fig. 1 dargestellten Ausführungsbeispiel eines erfindungsgemäß ausgestalteten Brennstoffeinspritzventils im Bereich II in Fig. 1, und

Fig. 3

einen vergrößerten Ausschnitt aus Fig. 2 im Bereich III.

An embodiment of the invention is shown in simplified form in the drawing and explained in more detail in the following description. It shows:

Fig. 1

FIG. 2 shows a schematic section through an exemplary embodiment of a fuel injection valve designed according to the invention in an overall view, FIG.

Fig. 2

a section of the in Fig. 1 illustrated embodiment of an inventively designed fuel injection valve in the area II in Fig. 1 , and

Fig. 3

an enlarged section Fig. 2 in area III.

Description of the embodiment

Fig. 1 shows a sectional view of an embodiment of a fuel injection valve according to the invention 1. The fuel injection valve 1 is designed in the form of a fuel injection valve 1 for fuel injection systems of mixture-compression, spark-ignition internal combustion engines. The fuel injection valve 1 is suitable for direct Injecting fuel into a combustion chamber, not shown, of an internal combustion engine.

The fuel injection valve 1 consists of a nozzle body 2, in which a valve needle 3 is arranged. The valve needle 3 is in operative connection with a valve closing body 4, which cooperates with a arranged on a valve seat body 5 valve seat surface 6 to a sealing seat. The valve closing body is formed almost spherical and thereby contributes to an offset-free guidance in the valve seat body 5. In the exemplary embodiment, the fuel injection valve 1 is an inwardly opening fuel injection valve 1, which has two injection openings 7. The spray openings 7 open according to the invention in extensions 38 in the valve seat body 5, which serve as coking. A detailed illustration of the spray openings 7 is the Fig. 2 and the following description.

The nozzle body 2 is sealed by a seal 8 against an outer pole 9 of a magnetic coil 10. The magnetic coil 10 is encapsulated in a coil housing 11 and wound on a bobbin 12, which rests against an inner pole 13 of the magnetic coil 10. The inner pole 13 and the outer pole 9 are separated by a gap 26 and are based on a connecting member 29 from. The magnetic coil 10 is energized via a line 19 from a via an electrical plug contact 17 can be supplied with electric current. The plug contact 17 is surrounded by a plastic casing 18, which may be molded on the inner pole 13.

The valve needle 3 is guided in a valve needle guide 14, which is designed disk-shaped. On the other side of the dial 15 is an armature 20. This is connected via a first flange 21 frictionally with the valve needle 3 in connection, which by a weld 22 with the first flange 21st connected is. On the first flange 21, a return spring 23 is supported, which is brought in the present design of the fuel injection valve 1 by a sleeve 24 to bias.

Downstream of the armature 20, a second flange 34 is arranged, which serves as a lower anchor stop. He is connected via a weld 35 frictionally connected to the valve needle 3. Between the armature 20 and the second flange 34, an elastic intermediate ring 33 for damping armature bouncers when closing the fuel injection valve 1 is arranged.

In the valve needle guide 14 and the armature 20 run fuel channels 30 and 31. The valve closing body 4 are formed 32 bevels, which lead the fuel to the sealing seat. The fuel is supplied via a central fuel supply 16 and filtered by a filter element 25. The fuel injection valve 1 is sealed by a seal 28 against a distribution line, not shown. Another seal 36 seals against the likewise not shown cylinder head of the internal combustion engine.

In the idle state of the fuel injection valve 1, the first flange 21 is acted on the valve needle 3 by the return spring 23 counter to its stroke direction so that the valve closing body 4 is held on the valve seat 6 in sealing engagement. The armature 20 rests on the intermediate ring 33, which is supported on the second flange 34. Upon excitation of the magnetic coil 10, this builds up a magnetic field, which moves the armature 20 against the spring force of the return spring 23 in the stroke direction. In this case, the armature 20 takes the first flange 21, which is welded to the valve needle 3, and thus the valve needle 3 also in the stroke direction with. The valve closing body 4, which is in operative connection with the valve needle 3, lifts off from the valve seat surface 6, as a result of which the fuel guided to the spray opening 7 is sprayed off.

If the coil current is turned off, the armature 20 drops after sufficient degradation of the magnetic field by the pressure of the return spring 23 on the first flange 21 from the inner pole 13, whereby the valve needle 3 moves against the stroke direction. As a result, the valve closing body 4 is seated on the valve seat surface 6 and the fuel injection valve 1 is closed. The armature 20 is seated on the anchor stop formed by the second flange 34.

According to the invention, as is Fig. 2 shows, preferably stepped spray openings 7 provided in the valve seat body 5. This measure serves to protect against coking in the area of the outlets of the spray openings 7. A precipitation of fuel in the region of the spray openings otherwise causes an accumulation of combustion residues, which the diameter of the Spray openings 7 and thus reduce the amount of fuel sprayed off increasingly. As a result, the fuel injection valve 1 is limited in its function and no longer provides enough fuel for combustion in the combustion chamber of the internal combustion engine. An increased fuel consumption and a deterioration of the emission values are the result.

bei einem vorgegebenen Durchmesser d der Abspritzöffnungen 7. Eine reduzierte Länge 1' der Abspritzöffnungen 7 zuströmseitig der Erweiterung 38 darf für eine optimale Strahlaufbereitung einen bestimmten Wert nicht überschreiten. Die Bemaßungen gehen aus dabei Fig. 3 hervor. Das Verhältnis der Länge 1' zum Durchmesser d ist also $${\mathrm{l}}^{\prime }\le 3\cdot \mathrm{d}\mathrm{.}$$

An overall length 1 of the ejection openings 7 is in this case $$\mathrm{l}>3\cdot \mathrm{d}$$

for a given diameter d of the ejection openings 7. A reduced length 1 'of the ejection openings 7 on the inflow side of the extension 38 must not exceed a certain value for optimum jet preparation. The dimensions go out thereby Fig. 3 out. The ratio of the length 1 'to the diameter d is so $${\mathrm{l}}^{\text{'}}\le 3\cdot \mathrm{d}\mathrm{,}$$

In Fig. 3 The above dimensions are listed.

wobei $$0,3\le \mathrm{c}\le 0,6\left[{\mathrm{mm}}^2{\mathrm{Mpa}}^{0,5}\right]$$

ist. n bezeichnet die Anzahl der Abspritzöffnungen 7 und beträgt mindestens 2, p ist der in der Brennstoffverteilerleitung anliegende Brennstoffdruck in Mpa.The diameter d of the ejection openings 7 is thereby $$\mathrm{d}={\left(\frac{4\cdot c}{\pi \cdot n\cdot p^{0.5}}\right)}^{0.5}.$$

in which $$0.3\le \mathrm{c}\le 0.6\left[{\mathrm{<figure-callout\; id="2"\; label="mm"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">mm</figure-callout>}}^2{\mathrm{Mpa}}^{0.5}\right]$$

is. n denotes the number of spray openings 7 and is at least 2, p is the fuel pressure in Mpa applied in the fuel rail.

The ejection openings 7 can be attached anywhere on the valve seat body 5. The configuration of the ejection openings 7 may consist of one or more round or elliptical, concentric or eccentric to each other or to a center of the valve seat body 5 arranged hole circles or one or more parallel, oblique, offset or not offset from each other arranged straight or curved rows of holes.

A distance between centers of the ejection openings 7 can be equidistant or different, but should be at least 180% of the diameter d of the ejection openings 7 for manufacturing reasons. The spatial orientation of a longitudinal axis of the ejection openings 7 can for each spray opening. 7 to be different. However, none of the longitudinal axes is directed to a not further shown, also arranged in the combustion chamber of the internal combustion engine spark plug. As a result, a shortened life of the spark plug can be avoided.

The entirety of all spray openings 7 injects a mixture cloud into the combustion chamber whose center of gravity axis can be inclined in any spatial direction with respect to a longitudinal axis 37 of the fuel injection valve 1 between 0 ° and 70 ° and whose conical expansion is between 30 ° and 100 °.

mit $$\mathrm{k}=0,06\mathrm{mm}/{\mathrm{Mpa}}^{0,5}$$

und dem Brennstoffdruck p in der Brennstoffverteilerleitung in Mpa.The wall thickness t of the valve seat body 5 is calculated as follows: $$\mathrm{t}\ge \mathrm{k}\cdot {\mathrm{p}}^{0.5}\left[\mathrm{mm}\right].$$

With $$\mathrm{k}=0.06\mathrm{mm}/{\mathrm{Mpa}}^{0.5}$$

and the fuel pressure p in the fuel rail in Mpa.

Corresponding to the wall thickness t, the overall length 1 and the reduced length 1 'of the spray-discharge openings 7 are obtained with the respective inclination of the spray-discharge openings 7. The valve-seat body 5 can be machined in the corresponding areas in a simple manner.

The invention is not limited to the illustrated embodiment and z. B. for arbitrarily arranged spray openings 7 and for any construction of inwardly opening multi-hole fuel injectors 1, according to the following claims.

Claims (11)

1. Method for operating a fuel injection valve (1) for directly injecting fuel into a combustion chamber (39) of an internal combustion engine, having an excitable actuator (10), having a valve needle (3), which is operatively connected to the actuator (10) and which is acted on in a closing direction by a restoring spring (23), for actuating a valve closing body (4) which forms a sealing seat together with a valve seat surface (6) which is formed on a valve seat body (5), and having a number n of at least n = 2 ejection openings (7), with the ejection openings (7) widening into a widened portion (38) in an ejection direction of the fuel,
   characterized
   in that the pressure p of the fuel flowing through the fuel injection valve (1) is greater than 10 bar, with a wall thickness t of the valve seat body (5) amounting to t ≥ k*p^0.5 [mm], where k = 0.06 mm/Mpa^0.5 and p, in Mpa, is the fuel pressure prevailing in the fuel distribution line,
   in that the ratio of a total length 1 of the ejection openings (7) to a smallest diameter d of the ejection openings amounts to 1 s 3*d,
   in that a reduced length 1' of the ejection openings (7) at the inflow side of the widened portion (38) amounts to 1' ≤ 3 · d, where d is the smallest diameter of the ejection opening and where the diameter d amounts to $$\mathrm{d}={\left(\frac{4\cdot c}{\pi \cdot n\cdot p^{0,5}}\right)}^{0,5}\left[\mathrm{mm}\right],$$

   

   
   where c is a constant, and
   in that the value of c lies in the range 0.3 ≤ c ≤ 0.6 [mm² Mpa^0.5].
2. Method according to Claim 1,
   characterized
   in that the ejection openings (7) are arranged on one or more round or elliptical hole circles which are arranged concentrically or eccentrically with respect to one another or with respect to a central point of the valve seat body (5).
3. Method according to Claim 1 or 2,
   characterized
   in that the ejection openings (7) are arranged in one or more straight or curved hole rows which are arranged in parallel with one another, obliquely with respect to one another or so as to be offset or not offset with respect to one another.
4. Method according to one of Claims 1 to 3,
   characterized
   in that a spacing between central points of two adjacent ejection openings (7) is equidistant.
5. Method according to Claim 4,
   characterized
   in that the spacing between the central points of two adjacent ejection openings (7) amounts to at least 180% of the diameter (d) of the ejection openings (7).
6. Method according to one of Claims 1 to 5,
   characterized
   in that a spatial orientation of a longitudinal axis is different for each ejection opening (7).
7. Method according to one of Claims 1 to 6,
   characterized
   in that each ejection opening (7) opens out into a separate widened portion (38).
8. Method according to one of Claims 1 to 6,
   characterized
   in that the widened portions (38) of a plurality of ejection openings (7) are connected to one another.
9. Method according to Claim 8,
   characterized
   in that the widened portions (38) are arranged on one or more round or elliptical hole circles which are arranged concentrically or eccentrically with respect to one another or with respect to a central point of the valve seat body (5).
10. Method according to Claim 8,
    characterized
    in that the widened portions (38) are arranged in one or more straight or curved hole rows which are arranged in parallel with one another, obliquely with respect to one another or so as to be offset or not offset with respect to one another.
11. Method according to one of Claims 1 to 10,
    characterized
    none of the longitudinal axes of the ejection openings in that (7) is directed towards a spark plug which is arranged in the combustion chamber of the internal combustion engine.

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