WO2016146311A1

WO2016146311A1 - Valve of an internal combustion engine

Info

Publication number: WO2016146311A1
Application number: PCT/EP2016/053028
Authority: WO
Inventors: Christoph Luven; Frank Sticher
Original assignee: Mahle International Gmbh
Priority date: 2015-03-16
Filing date: 2016-02-12
Publication date: 2016-09-22
Also published as: DE102015204706A1

Abstract

The invention relates to a valve (2) of an internal combustion engine (1), in particular an inlet valve or an outlet valve, comprising a valve disc (3) that transitions into a valve shaft (5) via a valve throat (4). According to the invention: the valve shaft (5) has a diameter d ≤ 6mm; the valve shaft (5) has a first chamfer (6) at the end thereof facing away from the valve disc (3); the valve shaft (5) has at least one circumferential groove (7), wherein a second chamfer (8) is arranged in alignment with the first chamfer (6) at a transition of the valve shaft (5) to the circumferential groove (7); or the valve shaft (5) has at least one circumferential groove (7) and wherein a first section (17) that is rounded and aligned with the first chamfer (6) is arranged at a transition of the valve shaft (5) to the circumferential groove (7). In this way, in particular the assembly of the valve (2) can be facilitated.

Description

Valve of an internal combustion engine

The present invention relates to a valve of an internal combustion engine,

in particular an inlet valve or an outlet valve, with a valve disk, which merges via a valve throat into a valve stem, according to the

Preamble of claim 1. The invention also relates to a

Internal combustion engine with at least one such valve.

In modern internal combustion engines arise in particular at one

Exhaust side in the valve area very high exhaust pressures, which cause a strong pressure increase through the narrow gap of the valve guide. In the

Using a single-lipped valve stem seal and its failure, it can lead to an undesirable blow-by flow, which on the one hand hot exhaust gas can enter the room above the valve guide and

on the other hand, the oil in the narrow gap of the valve guide is blown out, which has a negative effect on the function.

For this reason, increasingly so-called double-lipped

Valve stem seals used, which have a gas seal in the direction of the combustion chamber. The additional sealing lip acts as a rule pressure boosting and is therefore hinterströmbar. Nevertheless, she is

comparatively elastic and unstable in order to optimally fit to the

Create outer contour of the valve stem. When mounting the valve, in which the valve stem is plugged into the already mounted in the engine valve guide and valve stem seal from below, but it can lead to an undesirable flipping or bending of the sealing lip, which is thus no longer fully functional. However, this is often noticed later in the operation of the vehicle or the internal combustion engine and affects for example, negative by increased wear, fuel or

Oil consumption or even higher exhaust emissions.

The present invention therefore deals with the problem of providing an improved or at least one alternative embodiment for a valve of the generic type, which overcomes in particular the disadvantages known from the prior art with respect to a valve stem seal.

This problem is inventively achieved by the subject matter of

independent claim 1 solved. Advantageous embodiments are

Subject of the dependent claims.

The present invention is based on the general idea, a

Valve stem of a valve of an internal combustion engine in such a way that the risk of folding or bending over a sealing lip of a

Valve stem seal is minimized at least. The valve according to the invention, which, for example, as an inlet valve or as an outlet valve at a

Internal combustion engine of a car is formed, in this case has a valve plate, which merges via a valve throat in the valve stem described above. The valve stem has at its end facing away from the valve plate, a free end, a short chamfer called Einführfase, and at least one circumferential groove, wherein at a transition of the valve stem to this circumferential groove for a first bevel, that is to Einführfase, the same second Bevel or a rounded, first section is arranged. In principle, such circumferential grooves are used for wedging a spring, which biases the valve in its closed position. By means of the first and second chamfer according to the invention, or the first chamfer and the first rounded section, in particular the necessarily avoidable and unwanted folding over of a sealing lip is reliably prevented, whereby not only an undesired blowby is prevented can be, but also increased wear, fuel and oil consumption and increased exhaust emissions. The second chamfer or the first rounded section in turn serves as an insertion aid and presses the latter outward in the event of contact with the sealing lip, as a result of which folding over of the same can be reliably prevented. With the valve according to the invention can thus be the same in the already in the

Internal combustion engine mounted valve guide and seal comparatively simple and yet highly reliable.

In an advantageous development of the solution according to the invention, the first chamfer is inclined by α> 25 °, preferably by α> 27 °, against a shaft axis. Additionally or alternatively, the second chamfer can be inclined by an equal angle α> 25 °, preferably by α> 27 ° against the shaft axis. By such a tendency, the guiding and outward pressing of the second sealing lip of the valve stem seal can be reliably ensured.

Suitably, the first chamfer has a width of 0.2 mm <bi <0.5 mm, in particular a width of bi of about 0.3 mm. By such an axial extent of the chamfer, a reliable guiding and radially outward displacement of the second sealing lip of the valve stem seal can be forced, without causing the risk of turning over the same. In the same way, of course, the second chamfer can have a similar width b2.

In an advantageous embodiment of the solution according to the invention a total of three adjacent circumferential grooves on the valve stem of the

Valve according to the invention provided with a second chamfer, a third chamfer and a fourth chamfer. The second to fourth chamfer can be designed analogous to the first chamfer. Of course, it is clear that the Valve according to the invention has at least one such circumferential groove, but of course may also have two or more such circumferential grooves. Instead of said chamfers, at least one rounded section can also be provided. Of course, all chamfers can be replaced by such rounded sections.

In a further advantageous embodiment of the solution according to the invention, at least one circumferential groove has two oppositely directed chamfers. In this case, two bevels per circumferential groove can thus be provided, which are mirrored against each other and formed substantially the same.

As a result, a disassembly of the valve from the valve train system can be simplified because the opposite chamfer the seal at

Pulling the valve stem displaced outwards.

Instead of the chamfers described above, at least one of them may also be formed as a rounded portion instead. Such a thing

Rounded, ie convex section is characterized in particular by a reduced notch effect. In principle, a chamfer is a chamfered surface, which is in contact with a lateral surface of the valve stem via a connecting edge. By rounding out this edge, it can be removed completely theoretically, which also provides another major advantage

can be achieved in that a rounded portion represents a significantly lower risk of injury to a resilient valve stem seal when the valve is inserted into the internal combustion engine.

The first section expediently has a radius of 1 mm <r <2 mm. Due to this relative to the valve stem diameter of <6 mm relatively large radius, the transition between the valve stem and the circumferential groove is extremely gently rounded and presses in contact with the sealing lip the latter to the outside, whereby a folding them can be reliably avoided.

The present invention is further based on the general idea of equipping an internal combustion engine with at least one such valve. As a result, not only the assembly of the individual valves in the internal combustion engine can be significantly simplified, but it can also be reliable

be excluded that a second lip of a double-lipped

Valve stem seal when inserting the valve stem in the

Internal combustion engine folds down and thereby undesirably during later operation of the internal combustion engine to increased wear,

Fuel or oil consumption or even leads to higher exhaust emissions. With the chamfers provided according to the invention on the circumferential grooves, a maximum advantage can thus be achieved with comparatively marginal expenditure.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated

Description of the figures with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components. Show, in each case schematically,

Fig. 1 is a sectional view through an inventive

Internal combustion engine in the range of a valve according to the invention,

2 is a detail view of Figure 1 in the region of a valve stem seal prior to insertion of the valve stem,

3 is a detailed view of the valve stem in one embodiment with a total of three circumferential grooves,

Fig. 4 is a representation as in Fig. 3, but with a valve stem with

only a single circumferential groove,

5 is a view as in Fig. 4, but with a rounded portion instead of a chamfer,

Fig. 6 is a detail view of the valve stem in an embodiment having a total of three circumferential grooves having rounded portions as transitions.

According to FIG. 1, an internal combustion engine 1 according to the invention, which may be used in particular in a motor vehicle, has a valve 2 which is designed, for example, as an inlet valve or as an outlet valve and which has a valve disk 3 which via a valve throat 4 into a valve stem 5 passes. According to the invention, the valve stem 5 now has a diameter of d <6 mm and, at its free end remote from the valve disk 3, has a first chamfer 6, usually also called chamfer (see in particular also FIGS. 3 to 6), and at least one Circumferential groove 7, according to FIGS. 1 to 3 and 6, a total of three circumferential grooves 7, wherein at a transition of the valve stem 5 to the circumferential groove 7 for a first chamfer 6, that is to Einführfase, rectified second chamfer 8 or a rectified and rounded, first Section 17 is arranged. The valve 2 according to the invention is guided via its valve stem 5 in a valve guide 9, in the course of which at the same time a valve stem seal 10 with a first

Sealing lip 1 1 and a second sealing lip 12 is arranged. By inventively provided first chamfer 6 (Einführfase) and also provided according to the invention second chamfer 8 and the section 17, an undesired folding over the second sealing lip 12 can be reliably avoided, whereby in particular a functional impairment of

Valve stem seal 10 can be effectively excluded during operation of the internal combustion engine 1. Such

Functional impairment can lead to unwanted blow-by, which leads to an increase in pressure in the cylinder head. In addition, increased wear, fuel and oil consumption as well as increased exhaust gas values occur in this case.

Preferably, the first chamfer 6, that is in the present case, the

Einführfase, by α> 25 °, preferably by α> 27 °, inclined against a shaft axis 13. In the same way, of course, the second chamfer 8 by an angle α> 25 °, preferably by α> 27 °, be inclined against the shaft axis 13.

If one looks at the valve 2 shown in FIGS. 1 to 3, one can recognize a total of three circumferential grooves 7, with the second chamfer 8, a third chamfer 14 and a fourth chamfer 15. Purely theoretically, all four chamfers 6, 8, 14 and 15 be formed identically, that is, for example, by α> 25 °, preferably by α> 27 °, compared to

Shank axis 13 to be inclined. Especially preferred is the case if the respective bevel 6, 8, 14 and 15 are inclined by 27 ° <α <41 ° with respect to the shaft axis 13. Referring again to Fig. 3, it can be seen that the first chamfer 6, that is in the present case the Einführfase, a width bi between 0.2 and 0.5 mm, in particular of about 0.3 mm. In the same or even identical manner thereby also the widths b2, b3 and _b4 of the second chamfer 8, the third chamfer 14 and the fourth bevel may be formed 15th By thus formed chamfers 6, 8, 14 and 15, in particular the leading to unwanted blow-by folding the second sealing lip 12 of the valve stem seal 10 can be reliably avoided, which is particularly of great advantage, since such unwanted folding the second sealing lip 12 only when fully assembled

Internal combustion engine 1 and in their operation by increased wear, fuel, oil consumption and increased emissions can be noticed.

Purely theoretically, it is of course also conceivable that at least one circumferential groove 7 two mutually facing chamfers 8, 16 or a

rounded portion 17 and an opposite chamfer 16, so that the chamfers 8, 16 and the portion 17 and the chamfer 16 not only in one direction, for example in the mounting direction of the valve 2 to develop their effect, but also in a disassembly of the same and doing an ideal outward bending of the second sealing lip 12.

As an alternative to the valve 2 illustrated in FIGS. 1 to 3, the valve stem 5 shown in FIG. 6 has a total of three adjacent circumferential grooves 7 with the first rounded portion 17, a second rounded portion 18 and a third rounded portion 19. In this case, the chamfers 8, 14 and 15 provided in this area are thus all together in the form of rounded sections 17, 18, 19. Of course, only at least one transition from the valve stem 5 to the circumferential groove 7 rounded and thus as rounded portion 17 may be formed, as shown for example in FIGS. 4 and 5. Such a rounded portion 17, 18, 19 between the valve stem 5 on the one hand and the circumferential groove 7 on the other eliminates in particular the otherwise between the chamfer 8, 14, 15 or 16 and the valve stem 5 imperatively arranged edge which in highly sensitive valve stem seals 10 may cause injury and thus could lead to a negative impact on the same.

Also, of course, a valve 2 with a valve stem 5 with a plurality of circumferential grooves 7 is conceivable, with chamfers 8, 14, 15 or sections 17, 18, 19 are provided in any combination.

On the opposite side of the circumferential groove 7, of course, a transition from the valve stem 5 to the circumferential groove 7 also broken, that is with a sharp edge, are shown (see Fig. 5), since such an edge upon insertion of the valve 2 through the valve stem guide in the

Valve stem seal 10 is not effective and when pulling it out of the valve stem seal 10 is not necessarily to avoid

Flipping the second sealing lip 12 can lead.

With the inventively designed valve stem 5 and the associated valve 2 thus a comparatively reliable and simple installation of the same in the internal combustion engine can be achieved ine 1, without having to go into the existing risk of flipping a sealing lip 12.

Claims

claims

1 . Valve (2) of an internal combustion engine (1), in particular an inlet valve or an outlet valve, with a valve disk (3) which merges via a valve throat (4) into a valve stem (5),

characterized,

- That the valve stem (5) has a diameter d <6mm,

in that the valve stem (5) has a first chamfer (6) at its end facing away from the valve disk (3),

in that the valve stem (5) has at least one circumferential groove (7), wherein a second chamfer (8) rectified to the first chamfer (6) is arranged at a transition of the valve stem (5) to the circumferential groove (7), or 5) has at least one circumferential groove (7) and wherein at a transition of the valve stem (5) to the circumferential groove (7) to the first chamfer (6) rectified and rounded, the first portion (17) is arranged.

2. Valve according to claim 1,

characterized,

- That the first chamfer (6) is inclined by α> 25 ° against a shaft axis (13), and / or

- That the second chamfer (8) is inclined by α> 25 ° against a shaft axis (13) or

- That the first portion (17) has a radius of 1 mm <r <2 mm.

3. Valve according to claim 1 or 2,

characterized, the first chamfer (6) has a width of 0.2 mm <bi <0.5 mm, in particular of bi approximately 0.3 mm.

4. Valve according to one of claims 1 to 3,

characterized,

that the second chamfer (8) has a width of 0.2 mm <b2 <0.5 mm, in particular of b2 about 0.3 mm.

5. Valve according to one of claims 1 to 4,

characterized,

- That the first chamfer (6) is inclined by 27 ° <α <41 ° against a shaft axis (13), and / or

- That the second chamfer (8) is inclined by 27 ° <α <41 ° against a shaft axis (13).

6. Valve according to one of the preceding claims,

characterized,

- That a total of three adjacent circumferential grooves (7) with the second chamfer (8), a third chamfer (14) and a fourth chamfer (15) are provided, or

- That a total of three adjacent circumferential grooves (7) with the first portion (17), a second rounded portion (18) and a third rounded portion (19) are provided.

7. Valve according to claim 6,

characterized,

- That the third chamfer (14) has a width of 0.2 mm <b3 <0.5 mm, in particular of b3 about 0.3 mm, and / or - That the fourth chamfer (15) each have a width of 0.2 mm <b ₄ <0.5 mm, in particular b ₄ about 0.3 mm.

8. Valve according to claim 6 or 7,

characterized,

- That the third chamfer (14) is inclined by 27 ° <α <41 ° against the shaft axis (13), and / or

- That the fourth chamfer (15) is inclined by 27 ° <α <41 ° against the shaft axis (13).

9. Valve according to one of claims 6 to 8,

characterized,

in that at least one circumferential groove (7) has two mutually facing chamfers (8, 16).

10. Internal combustion engine (1) with at least one valve (2) according to one of claims 1 to 9.