WO2012123131A1

WO2012123131A1 - Valve device, in particular outlet valve of a fuel high pressure pump of an internal combustion engine

Info

Publication number: WO2012123131A1
Application number: PCT/EP2012/050222
Authority: WO
Inventors: Nadja Eisenmenger; Rainer Wilms; Valentin Szermutzky; Dominik Brunner; Hans-Christoph Magel; Matthias Maess
Original assignee: Robert Bosch Gmbh
Priority date: 2011-03-14
Filing date: 2012-01-09
Publication date: 2012-09-20
Also published as: DE102011005487A1

Abstract

The invention relates to a valve device (34), in particular an outlet valve of a fuel high pressure pump (10) of an internal combustion engine, comprising a housing (20), a flow channel and a plate-shaped, moveable valve body (42) which is arranged in the flow channel and which comprises a sealing section (44) parts of which abut the housing side of a sealing seat (46) when the valve device (34) is closed. The parts of the sealing section (44) and the sealing seat (46) abutting each other form a contact area, and when the valve device (34) is closed, a wedge-shaped gap (50) is provided at least temporarily directly adjacent to the contact area (54) between the sealing section (44) and the sealing seat (46).

Description

Description title

Valve device, in particular outlet valve of a high-pressure fuel pump of an internal combustion engine

State of the art

The invention relates to a valve device according to the preamble of claim 1.

From the market known fuel systems of internal combustion engines, which have a high-pressure pump by means of a required amount of fuel in a high-pressure accumulator or fuel rail ("rail") is promoted. Frequently, non-return systems are used for this, in which

High pressure pump arranged quantity control valves take over the flow control. Furthermore, such a high-pressure pump has an outlet valve, which is prestressed, for example, by a valve spring and seals the fuel distributor against a delivery chamber of the high-pressure pump.

Thus, leakage from the fuel rail is returned to the engine

Low pressure range substantially prevented.

If a pressure is built up in the delivery chamber of the high-pressure pump by means of a corresponding piston movement, the outlet valve can open, provided that the pressure in the delivery chamber is greater than the pressure in the delivery chamber

Fuel distributor plus the force of the valve spring. Then the

compressed fuel can be pumped into the fuel rail. Often, the exhaust valve has a so-called flat seat with a comparatively large sealing seat width. The large seal seat width is required to minimize wear of the exhaust valve over its life. When you open the exhaust valve is a between the plate-shaped

Sealing portion of the valve body ("valve plate") of the exhaust valve and the Housing-tight sealing seat ("counter plate") existing contact area filled with fuel. In this case, an initially small gap is formed, which is rapidly increased by inflow of fuel. However, due to hydrodynamic effects, the hydraulic pressure prevailing in the gap temporarily drops sharply, causing the valve plate to "stick" to the sealing seat for a short time. Because at the same time the piston of the high-pressure pump is quickly moved further and compresses the fuel in the pumping chamber correspondingly quickly, the sticking creates a pressure peak in the pumping chamber and subsequently an undesired shockwave. As a result, pulsations of the fuel are excited and the operating noise of the high-pressure pump is increased.

Other embodiments of valves, such as a ball-and-cone valve, in principle do not have said sticking. However, in these valves, the moving mass is generally larger.

Patent publications from this field are, for example, DE 10 2006 055 832 A1, DE 10 2006 002 638 A1, DE 102 49 688 A1, DE 102 20 717 A1, DE 102 13 626 A1, and DE 101 38 362 A1 ,

Disclosure of the invention

The problem underlying the invention is achieved by a valve device according to claim 1. Advantageous developments are specified in subclaims. Features which are important for the invention can also be found in the following description and in the drawings, wherein the features, both alone and in different combinations, can be important for the invention, without being explicitly referred to again.

The invention has the advantage that an adhesive effect when lifting a plate-shaped movable valve body is reduced by a housing-side sealing seat of a hydraulic valve device and the mass of the valve body is reduced. A maximum delivery pressure can be reduced and the load on the housing of a high pressure pump and a required drive torque can be reduced. Furthermore, the degree of rotation of the high-pressure pump improves, pressure pulsations are reduced and an operating noise is lowered.

The valve device according to the invention has a flow channel in which the plate-shaped valve body arranged therein can control or block a fluid flow together with the sealing seat. The invention is based on the consideration that an adhesive effect on lifting of the valve body from the sealing seat is dependent on a surface of a contact region formed between a sealing portion of the valve body and the sealing seat. According to the invention, the area of the contact area is reduced by, when the valve device is closed, immediately adjacent to the contact area between

Sealing section and sealing seat a wedge-shaped gap is present. As a result, it is not necessary to form the valve body as a ball or as a cone, whereby space and mass moved are saved. At the same time, a leakage of the fluid to be controlled by the valve device can be kept small.

In particular, the invention provides that the wedge angle in the gap is at most about 15 °, more preferably at most about 5 °, even more preferably at most about 2 °. Thus, a particularly suitable angle range or particularly suitable angle for the design of the wedge-shaped gap is described.

An embodiment of the valve device according to the invention provides that the valve body and / or the sealing seat in the sealing area is conical. Of the

Sealing area is formed by the interaction of the housing-side sealing seat and the sealing portion. Due to the regional cone-shaped

Geometry of the valve body and / or the sealing seat properties of a cone valve can be achieved without too much sticking effect occurs when lifting the valve body, and without it being necessary to form the valve body as a complete cone.

An alternative embodiment of the valve device provides that the valve body is spherical in the sealing area or has a spherical convex curvature. As a result, the adhesive effect can also be significantly reduced without the valve body being completely designed as a ball. In order to Moving mass can be saved and the dynamics of the valve device can be improved. The spherical area or the spherical curvature may, for example, be made by machining or by cold working.

In addition, it is provided that the valve body has a substantially central concave recess. For example, the concave recess may have an approximately spherical cap-like geometry, whereby a first boundary surface of the wedge-shaped gap according to the invention is formed. A second boundary surface is formed by the sealing portion. As a result, moving mass can be saved and manufacturing costs are reduced.

A further embodiment of the valve device comprises a sealing seat which is spherical in the sealing region. This can - with a flat trained

Sealing portion of the valve body - a particularly simple way

inventive wedge-shaped gap can be achieved in the sealing area. In addition, it is possible the "ball shape" of the sealing seat in the direction of

For example, the axis of movement of the valve body to be "cut in half", so that still a - infinitesimal small - contact surface between the sealing seat and the sealing portion and thus a wedge-shaped gap are formed. The remaining ball shape of the sealing seat has radially outward or radially inward.

Furthermore, it is provided that the wedge-shaped gap is present only on one side of the sealing area, preferably on the downstream side. This enables a further advantageous embodiment of the valve device.

The valve device can be designed to be particularly simple if the valve body is dimensioned, in particular designed as a sufficiently thin plate, that it deforms when the valve device is closed due to the pressure difference across the sealing region and thereby produces the wedge-shaped gap. Here, the valve body can partially assume a spherical cap-like shape, which generates the gap according to the invention on an edge or on a surface of the sealing seat which is inclined with respect to the axis of movement of the valve device. As a result, the valve device is simpler, manufacturing costs can be reduced. Furthermore, the sealing seat may be formed so that it has an edge in the contact area, such that when the valve device is closed, a largely linear contact between the valve body and sealing seat is present.

As a result, on the one hand, a high pressure in the contact region can be achieved, wherein the wedge-shaped gap immediately adjacent to the contact region is formed without additional effort. The required sealing effect arises from the fact that the initially linear contact between the sealing seat and the sealing portion during operation of the valve device after a few

Switching cycles expanded to a narrow ring surface. In addition, small bumps and / or manufacturing tolerances can be compensated.

A further embodiment of the valve device provides that the sealing seat upstream and / or downstream of the contact region has a circumferential chamfer. As a result, when the valve device is open, a hydraulic flow resistance is lowered and the efficiency is thus improved.

The dynamics of the valve device is further improved when the valve body has recesses outside an environment of the sealing portion. By selectively eliminating material in less stressed areas of the valve body, the moving mass can be reduced and the dynamics of the

Valve device can be improved. Conversely, regions of the valve body that are subject to greater stress-in particular within an environment of the sealing section-can optionally be stiffened in order to prevent or reduce elastic deformations of the valve body. This can be the

Fatigue strength of the valve device can be increased. Suitable areas can be determined, for example, by means of a computer simulation.

Hereinafter, exemplary embodiments of the invention will be explained with reference to the drawings. In the drawing show:

Figure 1 is a schematic sectional view of a high-pressure fuel pump with a first embodiment of a sealing region of a

exhaust valve; Figure 2 is a sectional view of a second embodiment of the sealing area of the exhaust valve of Figure 1; Figure 3 is a sectional view of a third embodiment of the sealing area;

FIG. 4 shows a sectional view of a fourth embodiment of the sealing region;

Figure 5 is a sectional view of a fifth embodiment of the sealing area;

FIG. 6 shows a sectional view of a sixth embodiment of the sealing region;

FIG. 7 shows a sectional view of a seventh embodiment of the sealing region;

FIG. 8 shows a sectional view of an eighth embodiment of the sealing region;

Figure 9 is a sectional view of a ninth embodiment of the sealing area;

Figure 10 is a sectional view of a tenth embodiment of the sealing portion;

Figure 1 1 is a sectional view of an eleventh embodiment of the sealing area;

Figure 12 is a sectional view of a twelfth embodiment of the sealing portion;

Figure 13 is a sectional view of a thirteenth embodiment of the

Sealing area; and

FIG. 14 shows the sealing region of FIG. 13 in the case of a worn-off sealing seat.

The same reference numerals are used for functionally equivalent elements and sizes in all figures, even in different embodiments.

FIG. 1 shows a fuel pump 10 of a fuel system of FIG

Internal combustion engine in a schematic representation. The fuel pump 10 has a housing 20, in whose left portion in the drawing, an electromagnet 15 with a coil 22, an armature 24 and an armature spring 26 is arranged. Furthermore, the fuel pump 10 comprises an inlet 28 connected to a low-pressure line 7 with an inlet valve 30, and an outlet 32 connected to a high-pressure line 11 with a Exhaust valve, which is hereinafter referred to as valve means 34. The inlet valve 30 comprises a spring 31 and a valve element 33. The valve element 33 can be moved by means of a valve needle 35, which can be moved horizontally in the drawing and coupled to the armature 24. In one

5 delivery chamber 36, a piston 18 is arranged vertically movable in the drawing.

The piston 18 can be moved by means of a roller 40 of a - in this case elliptical - cam 17 in a cylinder 37. The cylinder 37 is formed in a portion of the housing 20. The inlet valve 30 is hydraulically connected via an opening 38 with the delivery chamber 36. The arranged within the Gehäuse0 20 volumes of the fuel pump 10 are substantially with

Fuel filled.

In the present case, a substantially plate-shaped valve body 42 of the valve device 34 (outlet valve) has an approximately spherical cap-shaped sealing section 44, which cooperates with a sealing seat 46 formed by an end face of an axial and housing-fixed collar. A valve spring 43 - and also the pressure prevailing at the outlet 32 hydraulic pressure - act on the valve body 42 in the drawing to the left, ie in the closed position. Between the sealing portion 44 and the sealing seat 46, a wedge-shaped gap 50 is present. The sealing seat 46 and the sealing portion 44

together form a sealing area (without reference number). The functional elements of the valve device 34 are designed substantially rotationally symmetrical. 5 In the left end region, the valve body 42 has a central recess 52. The sealing seat 46 is formed on an annular end portion 53 of the housing 20 and aligned substantially perpendicular with respect to a longitudinal axis 48. The sealing seat 46 and the sealing portion 44 lie on one another and form at the contact point a substantially linear contact area 54.

In operation, the fuel pump 10 delivers fuel from the inlet 28 to the outlet 32, the valve means 34 opening or closing corresponding to a respective pressure difference between the delivery space 36 and the outlet 32. In this case, the valve body 42 of the valve device 34 in the direction of

Longitudinal axis 48 moves horizontally in the drawing. Is the electromagnet 15th energized, the inlet valve 30 can be closed by the force of the spring 31. If the electromagnet 15 is not energized, the inlet valve 30 can be forcibly opened by the force of the armature spring 26. When the valve device 34 is opened, the wedge-shaped gap 50 allows a quick refilling of the sealing area with fuel. As a result, a so-called "adhesive effect" and thus a delayed opening of the valve device 34 can be substantially avoided. In particular, pressure pulsations in the fuel pump 10 ("high-pressure pump") can be reduced and an operating noise can be reduced.

Also in the following FIGS. 2 to 14, the functional elements of the valve device 34 are designed to be rotationally symmetrical about the longitudinal axis 48. However, this is not explicitly stated again. In addition, in the following Figures 5 to 12, the valve means 34 are shown in an open or partially opened state for better illustration. Furthermore, in the following Figures 2 to 14, the geometries shown, in particular the wedge-shaped gap 50, for the purpose of better illustration partially exaggerated.

FIG. 2 shows a second embodiment of the sealing region of the valve device 34, which is closed in the present case, in a sectional view. The valve body 42 in the right region of the drawing is designed similarly to the figure 1 and thus has a partially spherical or spherical contour. The sealing seat 46 has a circumferential chamfer 56 upstream and downstream of the contact region 54.

During operation of the valve device 34, the initially linear

Contact area 54 are transformed due to elastic and plastic deformations to a narrow annular surface contact. Nevertheless, the effective (annular) area of the contact region 54 generally remains relatively small.

Alternatively or additionally, the recess 52 on the in the

Drawing be arranged on the right axial side of the valve body 42. However, this is not shown in FIG. The embodiment shown in FIG the valve device 34 also has the advantage that the valve body 42 can rest stable and tight on the sealing seat 46 even with a possible eccentricity and / or tilting. FIG. 3 shows a third embodiment of the sealing area. In the present case is the

Sealing portion 44 of the valve body 42 with respect to the longitudinal axis 48 at right angles and flat. The annular end portion 53 of the housing 20, which is shown in the left-hand area of the drawing, has conical contours in some regions radially inward and radially outward. The sealing seat 46 is arranged on the annular end portion 53 in such a way that the sealing seat 46 is tilted (radially encircling) with respect to the longitudinal axis 48, ie is slightly conical.

As a result, the wedge-shaped gap 50 and, correspondingly, the line-shaped contact region 54 are formed between the sealing seat 46 and the sealing section 44.

FIG. 4 shows a fourth embodiment of the sealing region. In the present case, the sealing seat 46 and the sealing portion 44 with respect to the longitudinal axis 48 per se at right angles and flat. As a result of the high fuel pressure prevailing at the outlet 32-shown by an arrow 58 in FIG. 4-the radially inner portions of the elastic and comparatively thin valve body 42 are slightly inclined to the left and right in the drawing the radially outer sections are bent to the right. An auxiliary line 60 drawn at right angles to the longitudinal axis 48 additionally illustrates this. By bending the valve body 42 of the wedge-shaped gap 50 is formed. It may be for reasons of high

Fatigue resistance may be required that the valve body 42 has a particularly elastic material with a high yield strength.

FIG. 5 shows a fifth embodiment of the sealing area. In the present case, the sealing seat 46 is tilted radially in relation to a plane perpendicular to the longitudinal axis 48 by an angle W1. As a result, the wedge-shaped gap 50 (radially inward) and correspondingly the linear contact region 54 (radially outward) are formed between the sealing seat 46 and the sealing section 44.

In addition, in FIG. 5 an edge 61 is designated in the contact region 54. By means of the edge 61, a largely line-shaped contact between the valve body 42 and the sealing seat 46 is generated when the valve device 34 is closed. FIG. 6 shows a sixth embodiment of the sealing region. In the present case, the sealing seat 46 has two chamfers 62 each having an angle W2 and W3, which form the line-shaped contact region 54 at a vertex. Accordingly, between the sealing seat 46 and the sealing portion 44 two wedge-shaped

Column 50 each formed radially inward and radially outward. The angles W2 and W3 can also have mutually different values. Also, a ratio d2 / d1 of the distances d1 and d2 may be in a range of zero to one.

FIG. 7 shows a seventh embodiment of the sealing region. In the present case, the sealing seat 46 has a spherical contour symmetrical to a line 64 parallel to the longitudinal axis 48. As a result, a - at least theoretically - linear contact region 54 and two wedge-shaped gaps 50 are likewise formed.

Figures 8 and 9 show an eighth and a ninth embodiment of the sealing area. Starting from the embodiment of FIG. 7, the radially inner and outer portions of the line 64 are crowned

formed annular end portion 53 used for the sealing seat 46.

FIG. 10 shows a tenth embodiment of the sealing region. In the present case, the valve body 42 has a central concave recess 66. The sealing seat 46 is aligned at right angles to the longitudinal axis 48. When the valve body 42 abuts against the end section 53 or the sealing seat 46 when the valve device 34 is closed, an approximately linear contact region 54 can again be formed at an outer radius of the abutment because of the concave recess 66

Sealing seat 46 and a wedge-shaped gap 50 are formed. In addition, the mass of the valve body 42 is reduced by the concave recess 66. FIG. 11 shows an eleventh embodiment of the sealing area. In the present case, the valve body 42 has a circumferential and radially outwardly directed

Bevel 68 on. When the valve device 34 is closed, the

Inclined surface 68 along with the longitudinal axis 48 at right angles

aligned sealing seat 46 in turn a roughly linear

Form contact area 54 and a wedge-shaped gap 50. FIG. 12 shows a twelfth embodiment of the sealing region. In the present case, the valve body 42 has a circumferential and radially inwardly directed

Slanted surface 70 on. When the valve device 34 is closed, the

Inclined surface 70 together with the longitudinal axis 48 at right angles

aligned sealing seat 46 in turn a roughly linear

Form contact area 54 and a wedge-shaped gap 50.

Figure 13 shows a thirteenth embodiment of the sealing region, wherein the valve device 34 is shown in the closed state. In the present case, the annular end section 53 of the housing 20 has a radially circumferential recess 72. Accordingly, a radial dimension 74 of the end portion 53 is reduced by a radial dimension 76, so that the surface of the sealing seat 46 is comparatively small. In the present case, the sealing seat 46 and the sealing portion 44 with respect to the longitudinal axis 48 are rectangular and planar. However, the valve body 42 - similar to Figure 4 - as a result of the prevailing at the outlet 32 high fuel pressure according to the arrow 58 is bent radially. As a result, an annular contact region 54 and a wedge-shaped gap 50 are again formed.

FIG. 14 shows the sealing region of FIG. 13 after a longer service life of the valve device. As a result of the comparatively strong abutments of the sealing section on the sealing seat, the end section 53 or the sealing seat 46 has been plastically deformed. In the present case, this was done in such a way that the previously linear contact region 54 is enlarged radially to such an extent that the

Contact area 54 now includes the entire between the sealing seat 46 and the sealing portion 44 possible contact surface.

Thanks to the radially circumferential recess 72, however, this contact surface is limited. When opening the valve device 34, although it comes to the undesirable adhesive effect when lifting the valve body 42 of the

Sealing seat 46, but the force to be overcome is comparatively low. As can be seen from the drawing, the end portion 53 is designed such that even with a further wear on the sealing seat 46 said contact surface is not further increased.

Claims

claims

Valve means (34), in particular outlet valve of a high-pressure fuel pump (10) of an internal combustion engine, with a housing (20), a flow channel and arranged in the flow channel plate-shaped movable valve body (42) having a sealing portion (44) which with closed valve device (34) partially applied to a housing-side sealing seat (46), wherein the contiguous sections of sealing portion (44) and sealing seat (46) form a contact region (54), characterized in that at

closed valve means (34) immediately adjacent to

Contact region (54) between the sealing portion (44) and sealing seat (46) at least temporarily a wedge-shaped gap (50) is present.

2. Valve device (34) according to claim 1, characterized in that the wedge angle in the gap (50) is at most about 15 °, more preferably at most about 5 °, even more preferably at most about 2 °.

3. Valve device (34) according to any one of the preceding claims, characterized in that the valve body (42) and / or the sealing seat (46) is conical in the sealing region.

4. Valve device (34) according to any one of the preceding claims, characterized in that the valve body (42) is spherical in the sealing area.

5. Valve device (34) according to any one of claims 1 or 2, characterized

characterized in that the valve body (42) has a substantially central concave recess (66).

6. Valve device (34) according to any one of the preceding claims, characterized in that the sealing seat (46) is spherical in the sealing region.

7. Valve device (34) according to any one of the preceding claims, characterized in that the wedge-shaped gap (50) is present only on one side of the sealing region, preferably on the downstream side.

8. Valve device (34) according to any one of the preceding claims, characterized in that the valve body (42) is dimensioned, in particular designed as a sufficiently thin plate that it deforms when the valve device (34) due to the pressure difference across the sealing region and thereby creating the wedge-shaped gap (50).

9. Valve device (34) according to one of the preceding claims, characterized in that the sealing seat (46) in the contact region (54) has an edge (61), such that when the valve device (34) is closed, a largely linear contact between the valve body (42 ) and sealing seat

(46) is present.

10. Valve device (34) according to any one of the preceding claims, characterized in that the sealing seat (46) upstream and / or

downstream of the contact region (54) has a circumferential chamfer (62).

1 1. Valve device (34) according to at least one of the preceding

Claims, characterized in that the valve body (42) has recesses (52) outside an environment of the sealing portion (44).