EP1200729A1

EP1200729A1 - Method for adjusting the valve lift of an injection valve

Info

Publication number: EP1200729A1
Application number: EP00958155A
Authority: EP
Inventors: Ferdinand Reiter
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1999-07-14
Filing date: 2000-07-14
Publication date: 2002-05-02
Anticipated expiration: 2020-07-14
Also published as: KR20020027487A; DE50008142D1; DE19932762A1; US6786432B1; BR0013158A; EP1200729B1; JP2003504551A; WO2001004487A1

Abstract

The invention relates to a method for adjusting the valve lift of an injection valve, in particular, of a fuel-injection valve for mixture-compression, spark-ignited internal combustion engines. The valve has a fuel inlet, an excitable actuating device (1, 2, 26, 35) which is used to displace a valve needle (19) comprising a valve closure member (21), a fixed valve seat (32), configured on a valve seat element (29), with which the valve closure member (21) interacts to open and close the valve and a fuel outlet (33). The valve also has a valve seat support (16), comprising an internal longitudinal cavity (18) for accommodating the valve needle (19). The valve needle (19) executes a lifting stroke between a closed valve position and an open valve position. The valve seat support (16) is preshaped with at least one protuberance (43) which projects radially outwards. In order to adjust the lifting stroke of the valve needle (19), the protuberance (43) is plastically deformed in a radial direction in relation to the longitudinal cavity (18).

Description

Procedure for adjusting the valve lift of an injection valve

State of the art

The invention is based on a method for adjusting the valve lift of an injection valve according to the preamble of claim 1.

A method for producing a valve is already known (EP 0 497 931 B1), in which a valve seat part consisting of a valve seat body and a perforated body is deformed between two weld seams in order to adjust the valve needle stroke, which leads to damage to the weld seams and to deformations on the valve seat body can lead.

In addition, from DE 196 40 782 AI a method for adjusting the valve lift on an injection valve is already known, in which the valve seat support is plastically deformed by a on the circumference of the valve seat support

Constriction is introduced. The deformation is basically carried out on the basis of a tubular or sleeve-shaped cylindrical component. The valve seat support is thus deformed immediately to adjust the valve lift. Advantages of the invention

The inventive method for adjusting the valve lift of an injection valve with the characterizing features of claim 1 has the advantage that the stroke of the valve needle can be adjusted in a simple manner, without the risk of undesirable force acting on the valve seat element.

In a particularly advantageous manner, the valve lift can be set very sensitively and in a defined manner. Compared to the known stroke adjustment method, the method according to the invention allows reliable adjustment with even tighter tolerances.

Advantageous further developments and improvements of the method specified in claim 1 are possible through the measures listed in the subclaims.

It is particularly advantageous to design the at least one elevation on the connecting part / valve seat support so that it rotates through 360 °. The elevation can be introduced as a bead, in particular by rolling.

The deformation tools causing the deformation of the elevation advantageously act on the elevation in the radial direction. If an axial force is applied to the elevation using a deformation tool, the deformation tool must be designed in such a way that the direction of deformation of the elevation is nevertheless radial. Drawing

Embodiments of the invention are shown in simplified form in the drawing and explained in more detail in the following description. 1 shows it

Embodiment of an injection valve, on which a stroke adjustment according to the invention is possible, FIG. 2 shows a first example of a deformation tool, FIG. 3 shows a second example of a deformation tool, FIG. 4 shows a third example of a deformation tool and FIG. 5 shows a fourth example of a deformation tool.

Description of the embodiments

The electromagnetically actuated valve partially shown in FIG. 1 in the form of a

Fuel injection valve for fuel injection systems of mixture-compressing, spark-ignited internal combustion engines is particularly suitable for the direct injection of fuel into a not shown

Combustion chamber. The fuel injector has a tubular core 2 surrounded by a magnetic coil 1 as a so-called inner pole. A coil body 3 receives a winding of the magnetic coil 1 and, in conjunction with the core 2, enables a particularly compact structure of the injection valve in the

Area of the magnetic coil 1. Instead of an electromagnetic circuit, piezo actuators or magnetostrictive actuators are also suitable as excitable actuating elements.

With a lower core end 9 of the core 2, a tubular metallic intermediate part 12 is connected, for example by welding, concentrically to a longitudinal valve axis 10 and partially surrounds the core end 9 axially. Downstream of the bobbin 3 and the intermediate part 12 extends a largely tubular, but for the application of Method according to the invention for adjusting the valve lift of preformed valve seat support 16 which is, for example, firmly connected to the intermediate part 12. A longitudinal opening 18 extends in the valve seat support 16 serving as a connecting part and representing a thin-walled sleeve. In the longitudinal opening 18, for example, a rod-shaped valve needle 19 is arranged, which has a valve closing section 21 at its downstream end.

The injection valve is actuated in a known manner, e.g. electromagnetically. For the axial movement of the valve needle 19 and thus for opening against the spring force of a return spring 25 or closing the injection valve, the electromagnetic circuit with the magnet coil 1, the core 2 and an armature 26 is used. The armature 26 is with the end facing away from the valve closing section 21 Valve needle 19 connected by a weld and aligned with the core 2. In the downstream end of the valve seat carrier 16 facing away from the core 2, a guide and seat unit is tightly mounted in the longitudinal opening 18 by welding.

This guiding and seating unit comprises three disc-shaped elements that lie directly against one another with their end faces. A guide element 27, a swirl element 28 and a valve seat element 29 follow one another in the downstream direction. While the guide element 27 and the swirl element 28 are arranged entirely within the longitudinal opening 18, the valve seat element 29 with a stepped outer contour only partially projects into the longitudinal opening 18. In the region of an outwardly projecting shoulder 30, the valve seat element 29 is firmly and tightly connected to the valve seat carrier 16 on its downstream end face. The guide element 27, the swirl element 28 and the valve seat element 29 are also fixed to one another connected, wherein a weld seam on the outer circumference of the three elements 27, 28 and 29 offers.

A guide opening of the intermediate part 12 and a guide opening in the guide element 27 serve to guide the valve needle 19 during the axial movement along the longitudinal valve axis 10. conical tapering valve closing section 21 interacts with a valve seat surface 32 of valve seat element 29 tapering in the direction of the truncated cone. Starting from the valve seat surface 32, at least one outlet opening 33 extends through the valve seat element 29. In the exemplary embodiment shown, the outlet opening 33 is inclined at an angle to the longitudinal valve axis 10, which extends in a convexly curved spray region of the

Valve seat element 29 ends. The fuel flowing through the outlet opening 33 is subject to swirl because an atomization-improving swirl component is impressed on it in front of the valve seat surface 32 in the swirl element 28, in which, for example, several tangential swirl channels are provided.

One end position of the valve needle 19 is determined when the solenoid coil 1 is not energized by the valve closing section 21 resting against the valve seat surface 32, while the other end position of the valve needle 19 when the solenoid coil 1 is energized results from the armature 26 resting on the core end 9 of the core 2. The distance between the two end positions represents the valve lift, which is adjustable according to the invention. The magnet coil 1 is surrounded by a cup-shaped valve housing 35, which serves as a so-called outer pole. With its lower end facing the valve seat element 29, the valve housing 35 is firmly attached to the valve seat carrier 16, for example by means of a weld seam. The z. B. from a ferritic, the magnetic flux conductive material valve seat support 16 encloses the axially movable valve part consisting of armature 26 and valve needle 19 with the valve closing section 21 and partially the guide and seat unit. The valve seat support 16 is elongated, the valve seat support 16 can even make up half or more of the total axial extension length of the injection valve. With this design of the valve seat support 16, the

The injection point of the injection valve can be set far in advance, which can be desirable in certain internal combustion engines because of their idiosyncratic shape and limited installation space. When using the fuel injection valve as a direct injection valve, the injection point can be optimally set at a desired location in the combustion chamber. In the usual installation positions of injection valves for intake manifold injection, such a design means that the fuel injection valve with its downstream end and thus with its metering and

Spray area clearly extends into the intake pipe. As a result, targeted spraying onto one or more inlet valves largely avoids wetting the wall of the intake pipe and, as a result, reduces the exhaust gas emission of the internal combustion engine.

Through the use of the relatively cheap sleeve for the valve seat carrier 16, it is possible to turn on the usual in injection valves rotating parts, which are more voluminous and because of their larger outer diameter

Manufacture are more expensive than the valve seat support 16 to do without.

A sealing element 41 arranged in a groove 40 made on the outer circumference of the valve seat support 16 serves for Sealing between the circumference of the injection valve and a valve holder, not shown, in the cylinder head or on an intake line of the internal combustion engine. The sealing element 41 is made, for example, of a plastic such as PTFE.

The valve seat support 16 is characterized in that at least one radially outward elevation or curvature is provided in the form of a bead 43 which, for example, completely rotates in the circumferential direction. A plurality of radial beads 43 can also be formed over the axial length of the valve seat carrier 16. In addition to the at least one radially outward bulge 43, a plurality of circumferentially distributed, deepened formations in the form of beads 44, which increase the rigidity, can also be provided in another area of extension of the valve seat carrier 16. These beads 44 have a certain longitudinal extent. In the valve seat support 16 produced, for example, by deep drawing or from a tube by shaping, the bead 43 is introduced, for example, by rolling. Before the actual process of dividing the valve lift, there is a preformed component that has at least one outward radial elevation in the form of a bead 43.

For precise adjustment of the stroke of the valve needle 19, the circumference of the valve seat support 16 is plastically deformed, specifically in the region of the bead 43. As indicated by the arrow 45, the bead 43 is deformed with a radial force acting on the bead 43 , In this way, the valve seat support 16 can be changed very delicately and in a defined manner in its axial length, in particular enlarged, whereby a very exact adjustment of the valve stroke is possible. Before the bulge 43 is deformed, the static amount of fuel delivered during the static opening of the valve is first measured in a known manner as the actual amount. This actual quantity is compared with a predetermined nominal quantity of the fuel to be sprayed off in a computer and a nominal stroke of the valve needle 19 is determined therefrom. In another setting method, the actual actual stroke of the valve needle 19 is measured by means of a position measuring device and compared in a computer with the predetermined desired stroke. On the basis of the difference between the actual stroke and the desired stroke of the valve needle 19 determined by the computer, a control signal is generated which is used to actuate a deformation tool 48. The deformation tool 48 is subsequently actuated for the plastic deformation of the valve seat carrier 16 until the actual stroke (actual stroke) of the valve needle 19 corresponds to the desired stroke.

FIGS. 2 to 5 show several possibilities for the deformation of the valve seat carrier 16 according to the invention in the region of the bead 43 for adjusting the valve lift. FIG. 2 shows a deformation tool 48 which consists of two half-shells 49. Both half-shells 49 have an inner curved area with which they can grip around the bulge 43 of the valve seat support 16 over a large part of the circumference. A radial force is applied to the valve seat support 16 with the half-shells 49 in accordance with the directions of the arrows, so that its axial length changes.

A comparable deformation tool 48 is shown in FIG. 3, in which, however, instead of two half-shells 49, four tool segments 50 act on the valve seat support 16 in the region of the bead 43. The arrows again illustrate the direction of the force. The four tool segments 50 each encompass approximately A of the circumference of the bead 43.

Figure 4 is intended to illustrate two deformation options. In a first variant, the valve is fixed in its position in a manner not shown, and the deformation tool 48 with at least one roller 51 is moved in the direction of the radial arrow onto the valve seat support 16 and circles the valve seat support 16 for deforming the bead 43 in accordance with the arrow in the circumferential direction , In a second variant, however, the rolling tool 48, 51 can also be fixed, and the valve is moved towards the rolling tool 48, 51 and set in a rotational movement. It is also possible that both the valve with its valve seat support 16 and the rolling tool 48, 51 are moved towards one another and both are set in rotation.

A further possibility of deformation is shown in FIG. 5. The force acting on the bead 43 is carried out by the deformation tool 48 in the axial direction. The

Deformation tool 48 consists of at least two tool segments 52, each of which has a conical inner surface 53 which, when using the deformation tool 48, is directed toward the valve seat carrier 16. The taper of the tool segments 52 runs in such a way that the bead 43 is reduced in its radial height when the tool segments 52 are moved axially.

The bead 43 can also be deformed by magnetic shaping. For this purpose, a locally limited strong magnetic field is generated in the region of the bead 43. Since the valve seat carrier 16 is ferritic, for example, the deformation of the bead 43 and thus the valve lift can be set in a targeted manner via the strength of the magnetic field. The accuracy of the setting of the valve lift can be influenced by the geometry of the bead 43 (such as, for example, the flank angle and the radius) or by the sheet thickness of the valve seat carrier 16.

Claims

Expectations

1. Method for adjusting the valve lift of an injection valve, in particular one

Fuel injection valves for internal combustion engines, with a fuel inlet, with an excitable actuating device, through which a valve needle with a valve closing member can be moved, with a fixed valve seat formed on a valve seat element, with which the valve closing member interacts to open and close the valve, with a fuel outlet, and with a connecting part which has an inner longitudinal opening for receiving the valve needle and which is connected directly or indirectly to the valve seat element, the valve needle executing a stroke between a valve closed position and a valve open position, characterized in that the connecting part (16) is preformed by at least a radially outward elevation (43) is formed and to change the stroke of the

Valve needle (19) the elevation (43) is plastically deformable in the radial direction towards the longitudinal opening (18).

2. The method according to claim 1, characterized in that the elevation on the connecting part (16) is designed as a circumferential bead (43).

3. The method according to claim 1 or 2, characterized in that the elevation (43) is introduced by rolling.

4. The method according to any one of the preceding claims, characterized in that the deformation of the elevation (43) is carried out with a deformation tool (48) which consists of two half-shells (49).

5. The method according to any one of claims 1 to 3, characterized in that the deformation of the elevation (43) is carried out with a deformation tool (48) having four tool segments (50).

6. The method according to claim 4 or 5, characterized in that the tool segments (49, 50) have inner curved areas with which they encompass the elevation (43).

7. The method according to any one of claims 1 to 3, characterized in that the deformation of the elevation (43) is carried out with a deformation tool (48) which has at least one roller (51) acting on the elevation (43) as a rolling tool.

8. The method according to any one of claims 1 to 3, characterized in that the deformation of the elevation (43) is carried out with a deformation tool (48) which consists of at least two tool segments (52) which have conical inner surfaces (53).

9. The method according to any one of claims 1 to 3, characterized in that the deformation of the elevation (43) is carried out by magnetic forming.

10. The method according to any one of the preceding claims, characterized in that the connecting part (16) is made of a ferritic material which conducts the magnetic flux.