CN111794821A

CN111794821A - Valve mechanism for internal combustion engine

Info

Publication number: CN111794821A
Application number: CN202010162838.6A
Authority: CN
Inventors: 帕特里克·奥尔瑟; 托尔斯腾·伊内; 马库斯·瓦尔希
Original assignee: Mahle International GmbH
Current assignee: Mahle International GmbH
Priority date: 2019-04-01
Filing date: 2020-03-10
Publication date: 2020-10-20
Also published as: US20200308997A1; DE102019204589A1

Abstract

The invention relates to a valve train (1) having a camshaft (3) having a first cam (4) and a second cam (5) arranged adjacent to the first cam; having a rocker arm assembly (6) with a displacement pin (8) adjustable in an axial direction (7) on which a cam follower (9) is mounted; has an adjusting device (11) and has an adjustable control pin (12). Essential to the invention are: a guide profile (13) is provided, which is arranged on the camshaft (3), has a first guide rail (14) and a second guide rail (15) intersecting the first guide rail in an X-shape, the control pin (12) being selectively engageable in the first guide rail (14) or in the second guide rail (15), the adjusting device (11) comprising a control rod (16), which is displaceable parallel to the displacement pin (8), having a first control region (17), a second control region (18) and a neutral region (19) arranged in the axial direction (7) between the first control region (17) and the second control region (18).

Description

Valve mechanism for internal combustion engine

Technical Field

The invention relates to a valve train for an internal combustion engine, having a camshaft with a first cam and a second cam arranged adjacent to the first cam, according to the preamble of claim 1. The invention further relates to an internal combustion engine having such a valve mechanism.

Background

A generic valve train (valve train) for an internal combustion engine is known from DE102017205571a1, which has a camshaft with a first cam and a second cam arranged axially adjacent to the first cam. The known valve mechanism comprises a rocker arm assembly which is adjustable in the axial direction between at least two positions, on which a cam follower (here a cam roller) is mounted. In the shifting pin itself, an adjustable control pin of the adjusting device is arranged.

By means of the adjusting device, the cam follower can be adjusted between its two positions and thereby, in particular, the opening or closing of the respective cylinder of the internal combustion engine is influenced. The known adjusting device comprises a first adjustable control pin and a second adjustable control pin which interact in each case with a guide rail arranged on the camshaft. However, since the known adjusting device has two control pins and two separate guide rails, the entire adjustment of the valve mechanism is only possible in a relatively complicated manner.

Disclosure of Invention

The present invention therefore addresses the following problems: an improved or at least alternative embodiment is specified for valve mechanisms of the generic type, which is characterized in particular by a simplified construction.

According to the invention, this problem is solved by the subject matter of independent claim 1. Advantageous embodiments are the subject of the dependent claims.

By following the known valve mechanism, the invention is based on the following main idea: a guide profile is provided which has two guide rails which intersect one another in an X-shape and by means of which only a single adjustable control pin is required for the adjustment. The valve train for an internal combustion engine according to the invention comprises a camshaft having at least one first cam and a second cam arranged axially adjacent to the first cam, and a rocker arm lever assembly having a displacement pin which is adjustable in the axial direction between at least two positions, on which displacement pin a cam follower, for example a cam roller, is mounted. In this case, the cam roller will be, for example, fixed in the axial direction and mounted rotatably on the displacement pin. In the displacement pin itself, a control pin is arranged which is radially adjustable to the displacement pin by means of an adjusting device. According to the invention, the guide profile arranged on the camshaft is now equipped with a first guide rail and a second guide rail intersecting it in an X-shape. The control pin is thereby optionally engaged in the first or second guide rail and thereby adjusts the displacement pin between its two positions. The cam follower intersects the first cam at a first position of the shift pin and intersects the second cam at a second position of the shift pin. By means of different cam profiles, it is possible to produce an influence on the number of valve openings and the closing of the cylinder. The adjusting device comprises a control rod which is displaceable parallel to the displacement pin and has a first switching region, a second switching region and a neutral region arranged in the axial direction of the control rod between the first switching region and the second switching region, wherein the control pin can be adjusted into the first guide track when it comes into contact with the first control region and can be adjusted into the second guide track when it comes into contact with the second control region. With the valve mechanism according to the invention, it is thus possible to provide only a single control pin on the displacement pin and to bring about an adjustment of the displacement pin by means of this together with the guide profile according to the invention. By requiring only a single control pin, the displacement pin can be built up in a shorter axial direction, and the component variety is additionally reduced, with associated reduction in storage and logistics costs and assembly expenditure. By providing a guide profile according to the invention with two crossing guide rails, the guide profile as a whole can also be built more compactly and thus in a more space-saving manner. Overall, it is thus possible to realize an adjustable valve mechanism which is cheaper, more cost-effective and, in particular, also requires less installation space to form than the valve mechanism designs known from the prior art.

In an advantageous further development of the solution according to the invention, the adjusting device comprises a housing in which the control rod is guided and in particular also mounted. Such a housing can be formed, for example, in a cylindrical shape and comprises a housing opening via which the control pin can be brought into contact with the control region. Such a cylindrical housing in particular provides a solution in which the installation space is optimized if the control rod is arranged coaxially in the housing. Through the housing opening in the housing, in particular if the housing opening is, for example, facing downwards, a protected arrangement of the control rod and, in particular, also the adjustment mechanism required for the adjustment of the control rod in the housing can be realized, so that oil which strikes the housing, in particular on the outside, cannot enter the housing.

In an advantageous further development of the solution according to the invention, a solenoid is provided, in particular a coil surrounding the control rod and a permanent magnet arranged on the control rod, wherein the control rod is adjustable in its first or second position by energizing the solenoid. By such a solenoid, an actuating device for actuating a control rod and thus for actuating an adjusting device can be achieved that is cost-effective and very precise and with low maintenance costs. By means of the coaxial arrangement of the solenoid, in particular of the coil arranged on the control rod and the permanent magnet, it is additionally possible to create a solution which is additionally optimized with regard to the installation space arranged in a protected manner in the housing.

In an advantageous further development of the solution according to the invention, at least one spring is provided which preloads the control rod into its first or second position. In this case, the following technical means can be conceived: by means of said solution, the control rod is adjusted to its first position, for example by energizing the previously described solenoid, while the resetting is exclusively achieved by means of a spring. Thereby, it is also possible to achieve a position of the control rod predetermined by the spring and thus define a predetermined driven cam in case of a solenoid failure. Alternatively, it is also obviously conceivable to provide two solenoids, in particular two coils surrounding the control rod and two permanent magnets arranged on the control rod, wherein the control rod can be adjusted to its first or second position by alternating energization of the solenoids. Although such a solution is more expensive than a solution with a single solenoid and spring, in some cases a more rapid displacement can be brought about.

In an advantageous further development of the solution according to the invention, the first control region is arranged at a longitudinal end side of the control rod and is formed in a pot-shaped manner, wherein the spring is formed as a coil spring and is arranged at least partially in the first control region. In this case, the spring supports itself in the first control region at one end and for example on the housing at the other end. This results not only in a protected arrangement of the spring in the housing, but also in an at least partially protected arrangement in the first control region, as a result of which a true encapsulation of the spring and in particular its thus protected arrangement can be achieved.

In practice, a position sensor is provided via which the position of the control rod, and therefore also the position of the displacement pin of the valve mechanism, can be detected indirectly. Such a position sensor can be formed, for example, as a hall sensor. In particular, it is conceivable here for such a position sensor to monitor the position of the first or second control region.

In practice, the first control region and/or the second control region have a flat region, which is designed as a contact region with the control pin. In this way, an area contact with the control pin can be achieved, as a result of which a punctiform and area-integral distribution of the force transmission between the control region and the control pin is made possible, and thus in particular wear characteristics can be minimized.

In a further advantageous embodiment of the solution according to the invention, the first control area and the second control area have different diameters. In particular, different cam strokes can thereby be compensated for in a simpler manner.

Furthermore, the invention is based on the following main concepts: such a valve mechanism is provided for an internal combustion engine, and thereby the aforementioned advantages of the valve mechanism are transferred to the internal combustion engine.

Further important features and advantages of the invention emerge from the dependent claims, the figures and the associated description of the figures with the aid of the figures.

It will be appreciated that the features mentioned above and those yet to be explained below can be used not only in the respectively indicated combination but also in other combinations or on their own, without departing from the scope of the present invention.

Drawings

Preferred exemplary embodiments of the invention are illustrated in the figures and are described in more detail in the following description, wherein like reference numerals refer to identical or similar or functionally identical components.

In each case shown schematically in the drawings,

figure 1 is a valve mechanism for an internal combustion engine according to the invention in a view with a cut-out adjusting device,

figure 2 is a cross-sectional representation through the adjusting device according to figure 1,

fig. 3 is a representation as in fig. 2, but with another embodiment,

FIG. 4 is a view of a control lever having two control regions according to the present invention.

Fig. 5a to d show different control positions of the adjusting device.

Detailed Description

According to fig. 1, a valve train 1 according to the invention for an internal combustion engine 2 (not shown in detail) comprises a camshaft 3, which camshaft 3 has a first cam 4 and a second cam 5 arranged axially adjacent to the first cam 4. A rocker arm assembly 6 is likewise provided, which has a displacement pin 8 which is adjustable in the axial direction 7 between at least two positions, on which a cam follower 9, in particular a cam roller 10, is mounted. An adjusting device 11 (see also fig. 2, 3 and 5) and an adjustable control pin 12 arranged in the displacement pin 8, in particular mounted therein in the radial direction, are likewise provided. According to the invention, a guide profile 13 having a first guide rail 14 and a second guide rail 15 intersecting the first guide rail in an X-shape is now arranged on the camshaft 3. The control pin 12 engages here selectively into the first guide track 14 or into the second guide track 15 (according to fig. 1 into the first guide track 14) and thereby adjusts the displacement pin 8 with the cam follower 9 arranged thereon between its two positions, wherein the cam follower 9 (here the cam roller 10) interacts with the first cam 4 in the first position of the displacement pin 8 and with the second cam 5 in the second position of the displacement pin 8. According to fig. 1, the rocker arm lever assembly 6 comprises two cam followers 9, which are axially, rotatably arranged on the displacement pin 8 and each interact either with the associated first cam 4 or with the associated second cam 5.

Besides, the adjusting device 11 comprises a control rod 16 (see also fig. 4) which is displaceable parallel to the displacement pin 8 (i.e. in the axial direction 7), said control rod 16 having a first control region 17, a second control region 18 and a neutral region 19 arranged between the first control region 17 and the second control region 18. The control pin 12 is adjusted into the first guide rail 14 when it comes into contact with the first control region 17 and into the second guide rail 15 when it comes into contact with the second control region 18. In the neutral zone 19, the control pin 12 is neither in contact with the first control zone 17 nor with the second control zone 18 (see fig. 5a and 5c), with the result that no actuation of the control pin 14 by the adjusting device 11 takes place. With the adjusting device 11 according to the invention, only a single control pin 12 can be arranged in the displacement pin 8, as a result of which a significantly less costly solution with a lower number of components and a design with lower assembly expenditure is possible. By means of the guide profile 13 according to the invention with

guide rails

14, 15 which cross in an X-shape, it is additionally also possible to create a guide profile 13 which is optimized in terms of installation space, in particular in the axial direction, and which therefore requires less space. In summary, with the valve mechanism 1 according to the invention, it is therefore possible to create a solution which is simple in design and optimal in installation space.

It can also be noted from a review of fig. 1 to 5 that the adjusting device 11 comprises a housing 20, in which housing 20 the control rod 16 is guided or mounted in the housing 20. The housing 20 is in this case cylindrical in design and comprises a housing opening 21 via which housing opening 21 the control pin 12 can enter and come into contact with the

control areas

17, 18. The housing opening 21 can be arranged centrally on the adjusting device 11 or centrally on the side of the end of the housing 20. The control rod 16 is relatively easy to produce here, for example by turning (turning) or thermally joining the two

control regions

17, 18 on the control rod 16, as a result of which a simply designed and therefore cost-effective adjusting device 11 can be created. It is the case that the adjusting device 11 in the mounted state (see fig. 1) is arranged such that the housing opening 21 faces downwards, in particular because oil hitting the housing 20 cannot enter the housing, the control rod 16 also being arranged protected inside the housing 2.

For actuating or adjusting the control rod 16 with the

control regions

17, 18 arranged thereon, a solenoid 22 is provided, in particular in such a way that a coil surrounds the control rod (16) (see fig. 2) or in such a way that a coil surrounds the second control region 18 (see fig. 3), wherein, in addition, according to fig. 3, a permanent magnet 23 is arranged on the control rod 16. The permanent magnet 23 can obviously be integrated in the control rod 16 in another way, for example, as shown in fig. 2. Purely theoretically, the control rod 16 can also consist of a magnetizable material and thus be subjected to the force required to adjust the control rod 16 by the solenoid 22.

It can be noted from an inspection of fig. 1 to 3 that at least one spring 24 is provided, which preloads the control lever 16 and thereby also brings the two

control regions

17, 18 into their first or second position, in this case into their second position. By means of such a spring 24, in particular a fail-safe function can be achieved, which effects a predetermined position of the control rod 16 in the event of a failure of the solenoid 22 or in general in the event of a failure of the actuating device for adjusting the control rod 16. Instead of the spring 24, it is obviously possible to provide a further solenoid 22, so that in this case a total of two solenoids 22 are provided, which upon corresponding energization adjust the control rod 16 into its first or second position.

It can be noted from the views of fig. 1 to 5 that the first control region 17 is arranged on the longitudinal end side of the control rod 16 and is formed at the same time in the shape of a basin, wherein the spring 24, which in the present case is realized as a coil spring, is arranged at least partially in the first control region 17. Thereby, a protected arrangement of the spring 24 can be realized in the housing 20 and on the first control region 17 in the direction of the housing opening 21. A position sensor 25 (for example, a hall sensor) can likewise be provided, via which the position of the control rod 16 and thus of the two

control regions

17, 18 can be detected. This enables, for example, an exact control position to be transmitted to the motor controller in each case.

The first control area 17 and/or the second control area 18 can be embodied as a cylindrical control disc. In order to improve the contact between the control pin 12 and the

respective control region

17, 18, it can additionally be provided that the first control region 17 and/or the second control region 18 comprise a flat region 26 serving as a contact region for the control pin 12.

Looking now at the control positions of the adjusting device 11 according to the invention, it is apparent from fig. 5a to 5d that, according to fig. 5a, the actuator (i.e. in the present case the control rod 16) is retracted and the control pin 12 projects into the neutral zone 19, wherein no actuation thereof via the adjusting device 11 (i.e. the first control zone 17 or the second control zone 18) takes place. According to fig. 5b, the adjusting device 11 is now activated. For example by energising the solenoid 22, as a result of which the control rod 16 has been displaced to the left and the control pin 12 is in contact with the second control region 18. As a result, the control pin 12 is moved downward and is thus adjusted into the second guide track 15, now extends in the control pin 12 and is displaced to the left in the axial direction 5 through the guide track 15 into the neutral region 19, as shown in fig. 5 c. According to fig. 5d, the control rod 16 is moved to the right again, as a result of which the control pin 12 now comes into contact with the first control region 17, at which point it adjusts the control pin 12 into the first guide rail 14. It is evident from fig. 5a to 5d in all that the path of the control rod 16 required for the transition from the first cam 4 to the second cam 5 or back is short, which also contributes to minimizing the installation space. In addition, only a single adjusting device 11 or control pin 12 and guide profile 13 is required for each cylinder by the valve train 1 according to the invention. It is evident, furthermore, from fig. 1 to 5 that the two

control regions

17, 18 have different diameters, so that different cam strokes are thereby compensated.

With the valve drive 1 according to the invention and the internal combustion engine 2 equipped with such a valve drive according to the invention, it is therefore possible to achieve a solution which is simple in design, cost-effective and additionally optimized with regard to the installation space for switching between different cam profiles.

Claims

1. A valve mechanism (1) for an internal combustion engine (2),

-having a camshaft (3) with a first cam (4) and a second cam (5) arranged adjacent to the first cam,

-having a rocker arm lever assembly (6) with a sliding pin (8) which is adjustable in the axial direction (7) between at least two positions, on which a cam follower (9), in particular a cam roller (10), is mounted,

-having an adjusting device (11) for adjusting a control pin (12) arranged on the displacement pin (8),

it is characterized in that

-a guide profile (13) is provided, which is arranged on the camshaft (3), having a first guide rail (14) and a second guide rail (15) intersecting the first guide rail in an X-shape,

-the control pin (12) is selectively engaged in the first guide (14) or in the second guide (15) and thereby adjusts the displacement pin (8) between its two positions, so that the cam follower (9) interacts with the first cam (4) in a first position of the displacement pin (8) and with the second cam (5) in a second position of the displacement pin (8),

-the adjustment device (11) comprises a control rod (16) displaceable parallel to the displacement pin (8), having a first control region (17), a second control region (18) and a neutral region (19) arranged in the axial direction (7) between the first control region (17) and the second control region (18), wherein the control pin (12) is adjusted into the first guide rail (14) upon contact with the first control region (17) and into the second guide rail (15) upon contact with the second control region (18).

2. Valve mechanism according to claim 1, characterized in that the adjusting means (11) comprise a housing (20) in which the control rod (16) is guided.

3. Valve mechanism according to claim 1 or 2, characterized in that the first control region (17) and/or the second control region (18) is embodied as a cylindrical displacement disc.

4. Valve mechanism according to claim 2 or 3, characterized in that the housing (20) is formed cylindrically and comprises a housing opening (21) via which the control pin (12) can be brought into contact with the control region (17, 18).

5. Valve mechanism according to one of the preceding claims, characterized in that a solenoid (22), in particular a coil surrounding the control rod (16), and in particular a permanent magnet (23) arranged on the control rod (16) is provided, wherein the control rod (16) is adjustable into its first or second position by energizing the solenoid (22).

6. Valve mechanism according to one of the preceding claims, characterized in that two solenoids (22) are provided, in particular two coils surrounding the control rod (16), and in particular two permanent magnets (23) arranged on the control rod (16), wherein the control rod (16) is adjustable into its first or second position by alternately energizing the solenoids (22).

7. Valve mechanism according to any of the preceding claims, characterized in that at least one spring (24) is provided, which pre-loads the control rod (16) to its first or second position.

8. Valve mechanism according to claim 7, characterized in that the first control region (17) is arranged at a longitudinal end side of the control rod (16) and is designed in a pot shape, wherein a spring (24) is formed as a coil spring and is arranged at least partially in the first control region (17).

9. Valve mechanism according to one of claims 1 to 8, characterized in that a position sensor (15) is provided, via which the position of the control rod (16) can be detected.

10. Valve mechanism according to any of the preceding claims, characterized in that

-the first control zone (17) and/or the second control zone (18) comprise a flat zone (26) formed as a contact zone with the control pin (12), and/or

-the first control area (17) and the second control area (18) have different heights or diameters.

11. An internal combustion engine (2) having a valve mechanism (1) according to any one of the preceding claims.