U.S. patent application number 16/836909 was filed with the patent office on 2020-10-01 for valve train for an internal combustion engine.
The applicant listed for this patent is Mahle International GmbH. Invention is credited to Patrick Altherr, Thorsten Ihne, Markus Walch.
Application Number | 20200308997 16/836909 |
Document ID | / |
Family ID | 1000004837479 |
Filed Date | 2020-10-01 |
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United States Patent
Application |
20200308997 |
Kind Code |
A1 |
Altherr; Patrick ; et
al. |
October 1, 2020 |
VALVE TRAIN FOR AN INTERNAL COMBUSTION ENGINE
Abstract
The present disclosure describes a valve train for an internal
combustion engine. The valve train includes a camshaft with a first
cam and a second cam, a rocker lever assembly with a shifting pin
that is adjustable in an axial direction between at least two
positions, a cam follower mounted on the shifting pin, an adjusting
device for adjusting a control pin arranged in the shifting pin,
and a guide contour arranged on the camshaft having a first guide
track and a second guide track intersecting the first guide track
in an X-like manner. The control pin engages into the guide tracks
and adjusts the shifting pin to adjust the cam follower. The
adjusting device includes a control rod that is shiftable parallel
to the shifting pin and contacts the control rod.
Inventors: |
Altherr; Patrick;
(Stuttgart, DE) ; Ihne; Thorsten; (Stuttgart,
DE) ; Walch; Markus; (Bretten, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mahle International GmbH |
Stuttgart |
|
DE |
|
|
Family ID: |
1000004837479 |
Appl. No.: |
16/836909 |
Filed: |
March 31, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01L 1/18 20130101; F01L
1/34413 20130101; F01L 1/047 20130101 |
International
Class: |
F01L 1/344 20060101
F01L001/344; F01L 1/047 20060101 F01L001/047; F01L 1/18 20060101
F01L001/18 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 1, 2019 |
DE |
102019204589.8 |
Claims
1. A valve train for an internal combustion engine, comprising: a
camshaft with a first cam and a second cam arranged adjacent
thereto, a rocker lever assembly with a shifting pin that is
adjustable in an axial direction between at least two positions, on
which a cam follower is mounted, an adjusting device for adjusting
a control pin arranged in the shifting pin, a guide contour
arranged on the camshaft having a first guide track and a second
guide track intersecting the first guide track in an X-like manner,
the control pin engages into the first guide track or the second
guide track and adjusts the shifting pin between the at least two
positions, so that the cam follower in a first position of the
shifting pin interacts with the first cam and in a second position
of the shifting pin interacts with the second cam, and the
adjusting device including a control rod that is shiftable parallel
to the shifting pin having a first control region, a second control
region and a neutral region arranged in between in the axial
direction, wherein the control pin upon contact with the first
control region is adjusted into the first guide track and upon
contact with the second control region is adjusted into the second
guide track.
2. The valve train according to claim 1, wherein the adjusting
device further includes a housing structured and arranged to guide
the control rod.
3. The valve train according to claim 1, wherein at least one of
the first control region and the second control region is
structured as a cylindrical shifting disc.
4. The valve train according to claim 2, wherein the housing is
structured cylindrically and comprises a shell opening, via which
the control pin is contactable with the first control region and
the second control region.
5. The valve train according to claim 1, further comprising a
solenoid arranged on the control rod, wherein the control rod is
adjustable into the first position or the second position by
energising the solenoid.
6. The valve train according to claim 1, further comprising two
solenoids, wherein the control rod is adjustable into the first
position or the second position through alternative energising of
the two solenoids.
7. The valve train according to claim 1, further comprising at
least one spring, structured and arranged to preload the control
rod into the first position or the second position.
8. The valve train according to claim 7, wherein the first control
region is arranged on a longitudinal end side of the control rod
and has a pot-like shape, and wherein the at least one spring is
structured as a coil spring and is at least partly arranged in the
first control region.
9. The valve train according to claim 1, further comprising a
position sensor, structured and arranged to detect a position of
the control rod.
10. The valve train according to claim 1, wherein at least one of:
at least one of the first control region and the second control
region has a flattened region that provides a contact region for
the control pin, and the first control region and the second
control region have at least one of different heights and different
diameters from one another.
11. An internal combustion engine comprising: a valve train, the
valve train including: a camshaft with a first cam and a second cam
arranged adjacent thereto; a rocker lever assembly with a shifting
pin that is adjustable in an axial direction between at least two
positions, on which a cam follower is mounted; an adjusting device
for adjusting a control pin arranged in the shifting pin; a guide
contour arranged on the camshaft having a first guide track and a
second guide track intersecting the first guide track in an X-like
manner; the control pin engages into the first guide track or the
second guide track and adjusts the shifting pin between the at
least two positions, so that the cam follower in a first position
of the shifting pin interacts with the first cam and in a second
position of the shifting pin interacts with the second cam; and the
adjusting device including a control rod that is shiftable parallel
to the shifting pin a first control region, a second control region
and a neutral region arranged in between in the axial direction,
wherein the control pin upon contact with the first control region
is adjusted into the first guide track and upon contact with the
second control region is adjusted into the second guide track.
12. The internal combustion engine according to claim 11, wherein
the adjusting device further includes a housing structured and
arranged to guide the control rod.
13. The internal combustion engine according to claim 12, wherein
the housing has a cylindrical shape with a shell opening, and
wherein the control pin contacts the first control region and the
second control region via the shell opening.
14. The internal combustion engine according to claim 11, further
comprising a solenoid structured and arranged to adjust the control
rod into at least one of the first position and the second
position.
15. The internal combustion engine according to claim 11, further
comprising at least one spring structured and arranged to preload
the control rod into at least one of the first position and the
second position.
16. The internal combustion engine according to claim 11, wherein
at least one of the first control region and the second control
region has a flattened region that provides a contact region for
the control pin.
17. The internal combustion engine according to claim 11, wherein
the first control region and the second control region have
different heights from one another.
18. The internal combustion engine according to claim 11, wherein
the first control region and the second control region have
different diameters from one another.
19. The valve train according to claim 5, wherein the solenoid
includes a coil surrounding the control rod.
20. The valve train according to claim 5, wherein the solenoid
includes a permanent magnet arranged on the control rod.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to German Application No.
DE 10 2019 204 589.8 filed on Apr. 1, 2019, the contents of which
are hereby incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] The present invention relates to a valve train for an
internal combustion engine having a camshaft with a first and a
second cam arranged adjacent thereto. The invention additionally
relates to an internal combustion engine having such a valve
train.
BACKGROUND
[0003] From DE 10 2017 205 571 A1 a generic valve train for an
internal combustion engine having a camshaft with a first and a
second cam arranged axially adjacent thereto is known. The known
valve train comprises a rocker lever assembly that 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 an adjusting device is
arranged.
[0004] Through the adjusting device, the cam follower can be
adjusted between its two positions and thereby influence, in
particular switch on or switch off a corresponding cylinder of the
internal combustion engine. The known adjusting device comprises a
first adjustable control pin and a second adjustable control pin
which in each case interact with a guide track arranged on the
camshaft. However, because of the known adjusting device with two
control pins and the two separate guide tracks, the entire
adjustment of the valve train is only possible in a comparatively
involved manner.
SUMMARY
[0005] The present invention therefore deals with the problem of
stating an improved or at least an alternative embodiment for a
valve train of the generic type, which is characterized in
particular by a simplified construction.
[0006] According to the invention, this problem is solved through
the subject of the independent claim(s). Advantageous embodiments
are subject of the dependent claims.
[0007] With a valve train known per se, the present invention is
based on the general idea of providing a guide contour having two
guide tracks intersecting one another X-like, by way of which for
the adjustment merely a single adjustable control pin is required.
The valve train according to the invention for an internal
combustion engine comprises a camshaft having at least one first
cam and a second cam arranged axially adjacent thereto, and a
rocker lever assembly having a shifting pin that is adjustable in
the axial direction between at least two positions, on which a cam
follower, for example a cam roller, is mounted. In this case, a cam
roller would be mounted for example axially fixed and rotatable on
the shifting pin. In the shifting pin itself, a control pin that is
adjustable radially to the shifting pin by means of an adjusting
device is arranged. According to the invention, the guide contour
arranged on the camshaft is now equipped with a first guide track
and a second guide track intersecting the same X-like. Here, the
control pin optionally engages in the first or the second guide
track and thereby adjusts the shifting pin between its two
positions. In a first position of the shifting pin, the cam
follower interacts with the first cam and in a second position of
the shifting pin with the second cam. By way of different cam
profiles, an influencing of valve opening times can take place or a
switching-off of a cylinder. The adjusting device comprises a
control rod that is shiftable parallel to the shifting pin with a
first switching region, a second switching region and a neutral
region arranged in the axial direction of the control rod in
between, wherein the control pin upon contact with the first
control region is adjustable into the first guide track and upon
contact with the second control region into the second guide track.
With the valve train according to the invention it is thus possible
to merely provide a single control pin on the shifting pin and with
the same together with the guide contour according to the invention
bring about the adjusting of the shifting pin. Through the merely
one single required control pin it is possible to build the
shifting pin shorter in the axial direction and additionally reduce
the parts variety and connected with this also the storage and
logistical costs as well as the assembly expenditure. By providing
the guide contour according to the invention with two intersecting
guide tracks, the guide contour as a whole can also be built in a
more compact and thus more space-saving manner. Altogether, an
adjustable valve train can thus be realised which compared with the
valve train known from the prior art is formed less expensive in
design, more cost-effective and in particular also requires less
installation space.
[0008] 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 cylindrically for example and
comprise a shell opening, via which the control pin is contactable
with the control regions. Such a cylindrical housing offers a
particularly installation space-optimised solution provided the
control rod is arranged coaxially in the housing. By way of the
shell opening on the housing, a protected arrangement of the
control rod and in particular also of an adjusting mechanism
required for the adjustment of the control rod in the housing can
be achieved, provided that in particular the shell opening faces
downward for example, so that in particular oil impinging on the
housing shell on the outside cannot enter the housing.
[0009] In an advantageous further development of the solution
according to the invention, a solenoid, in particular a coil
surrounding the control rod, and a permanent magnet arranged on the
control rod are provided, wherein the control rod is adjustable in
its first or second position by energising the solenoid. By means
of such a solenoid, a cost-effective and extremely exact and
low-maintenance actuation device for actuating the control rod and
thus for actuating the adjusting device can be achieved. Through
the coaxial arrangement of the solenoid, in particular of the coil
and of the permanent magnet arranged on the control rod, an
installation space-optimised solution can be additionally created,
which is additionally arranged protected in the housing.
[0010] 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, a solution is thus conceivable with which for example the
previously described solenoid by energising brings about an
adjusting of the control rod into its first position, while a
resetting is exclusively effected by means of the spring. By way of
this, it can also be achieved that upon a failure of the solenoid a
position of the control rod that is predefined by the spring and
thus a predefined cam following is defined. Alternatively it is
obviously also conceivable that two solenoids, in particular two
coils surrounding the control rod and two permanent magnets
arranged on the control rod are provided, wherein the control rod
through alternative energisation of the solenoids is adjustable
into its first or second position. Although such a solution is more
expensive than a solution with a single solenoid and a spring, it
can however bring about a quicker shifting under certain
conditions.
[0011] In an advantageous further development of the solution
according to the invention, the first control region is arranged on
the longitudinal end side of the control rod and formed pot-shaped,
wherein the spring is formed as a coil spring and is at least
partly arranged in the first control region. In this case, the
spring supports itself at the one end in the first control region
and at the other end for example on a housing. This causes a
protected arrangement of the spring not only in the housing but
additionally at least partly also in the first control region, as a
result of which a veritable encapsulation of the spring and thus a
particularly protected arrangement of the same can be achieved.
[0012] Practically, a position sensor is provided via which a
position of the control rod and thus indirectly also a position of
the shifting pin or of the valve train can be detected. Such a
position sensor can be formed for example as a Hall sensor. In
particular it is conceivable here that such a position sensor
monitors the position of the first or second control region.
[0013] Practically, the first and/or second control region has/have
a flattened region which is designed as contact region to the
control pin. By way of this, an areal contact with the control pin
can be achieved as a result of which not only a punctiform but an
areal distribution of the force transmission between control region
and control pin is made possible and because of this wear
manifestations in particular can be minimised.
[0014] In a further advantageous embodiment of the solution
according to the invention, the first and the second control region
have different diameters. By way of this it is possible in
particular to comparatively easily compensate for different cam
strokes.
[0015] Furthermore, the present invention is based on the general
idea of equipping an internal combustion engine with such a valve
train and by way of this transfer the previously described
advantages of the valve train to the internal combustion
engine.
[0016] Further important features and advantageous of the invention
are obtained from the subclaims, from the drawings and from the
associated figure description by way of the drawings.
[0017] It is to be understood that the features mentioned above and
still to be explained in the following cannot only be used in the
respective combination stated but also in other combinations or by
themselves without leaving the scope of the present invention.
[0018] Preferred exemplary embodiments of the invention are shown
in the drawings and are explained in more detail in the following
description, wherein same reference numbers relate to same or
similar or functionally same components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] It shows, in each case schematically,
[0020] FIG. 1 a valve train for an internal combustion engine
according to the invention in a view with sectioned adjusting
device,
[0021] FIG. 2 a sectional representation through the adjusting
device according to FIG. 1,
[0022] FIG. 3 a representation as in FIG. 2, however with another
embodiment,
[0023] FIG. 4 a view of a control rod with two control regions
according to the invention,
[0024] FIGS. 5A to 5D illustrate different control positions of the
adjusting device.
DETAILED DESCRIPTION
[0025] According to FIG. 1, a valve train 1 according to the
invention for an internal combustion engine 2 which is not shown in
more detail comprises a camshaft 3 with a first cam 4 and a second
cam 5 arranged axially adjacent thereto. Likewise provided is a
rocker lever assembly 6 with a shifting pin 8 that is adjustable in
the axial direction 7 between at least positions, on which a cam
follower 9, in particular a cam roller 10, is mounted. Likewise
provided are an adjusting device 11 (see also FIGS. 2, 3 and 5) and
an adjustable control pin 12, which is arranged in the shifting pin
8, in particular radially mounted in the same. According to the
invention, a guide contour 13 having a first guide track 14 and a
second guide track 15 intersecting the same X-like is now arranged
on the camshaft 3. Here, the control pin 12 optionally engages into
the first or second guide track 14, 15 (according to FIG. 1, into
the first guide track 14) and thereby adjusts the shifting pin 8
with the cam followers 9 arranged thereon between its/their two
positions, wherein the cam follower 9, here the cam roller 10, in a
first position of the shifting pin 8, interacts with the first cam
4 and in the second position of the shifting pin 8 with the second
cam 5. According to FIG. 1, the rocker lever assembly 6 comprises
two cam followers 9, both of which are coaxially rotatably arranged
on the shifting pin 8 and each of which interacts either with an
associated first cam 4 or an associated second cam 5.
[0026] In addition to this, the adjusting device 11 comprises a
control rod 16 (see also FIG. 4) that is shiftable parallel to the
shifting pin 8, i.e. in the axial direction 7, with a first control
region 17, a second control region 18 and a neutral region 19
arranged in the axial direction in between. Upon a contact with the
first control region 17, the control pin 12 is adjusted into the
first guide track 14 while upon a contact with the second control
region 18 it is adjusted into the second guide track 15. In the
neutral region 19, the control pin 12 is neither in contact with
the first control region 17, nor with the second control region 18
(see FIGS. 5a and 5c), as a result of which no actuation of the
control pin 14 by the adjusting device 11 takes place. With the
adjusting device 11 according to the invention it is possible that
in the shifting pin 8 merely a single control pin 12 has to be
arranged, as a result of which a solution that is significantly
less expensive in design with a lower number of parts and with a
lower assembly expenditure can be achieved. Through the guide
contour 13 according to the invention with the guide tracks 14, 15
intersecting X-like, a guide contour 13 can be additionally also
created which is installation space-optimised in particular in the
axial direction and because of this requires little space.
Altogether, a solution that is simple in design and installation
space-optimised can thus be created with the valve train 1
according to the invention.
[0027] Viewing FIGS. 1 to 5 further it is noticeable that the
adjusting device 11 comprises a housing 20 in which the control rod
16 is guided or mounted. In the present case, the housing 20 is
cylindrical in design and comprises a shell opening 21, via which
the control pin 12 can enter into contact with the control regions
17, 18. The shell opening 21 can be arranged centrally on the
adjusting device 11 or on one side at an end of the housing 20.
Here, the control rod 16 is comparatively easy to produce, for
example by turning or thermal joining of the two control regions
17, 18 on the control rod 16, as a result of which an adjusting
device 11 that is simple in design and thus cost-effective can be
created. The circumstance that the adjusting device 11 in the
installed state (see FIG. 1) is arranged in such a manner that the
shell opening 21 faces downwards, the control rod 16 is also
arranged protected within the housing 2 since in particular oil
striking the housing 20 cannot enter the same.
[0028] For actuating or adjusting the control rod 16 with the
control regions 17, 18 arranged thereon a solenoid 22, in
particular in the manner of a coil surrounding the control rod (16)
(see FIG. 2) or in the manner of a coil surrounding the second
control region 18 (see FIG. 3) is provided, wherein in addition
according to FIG. 3 a permanent magnet 23 is arranged on the
control rod 16. This permanent magnet 23 can obviously be
integrated in the control rod 16 in another manner, as is shown for
example according to FIG. 2. Purely theoretically, the control rod
16 can also consist of a magnetisable material and thereby be
subjected to the forces required for adjusting the control rod 16
by the solenoid 22.
[0029] Viewing FIGS. 1 to 3 it is noticeable that at least one
spring 24 is provided, which preloads the control rod 16 and
thereby also the two control regions 17, 18 into its first or
second position, here into its second position. By means of such a
spring 24, a failsafe function can be realised in particular, which
enforces a predefined position of the control rod 16 upon a failure
of the solenoid 22 or generally upon a failure of an actuation
device for adjusting the control rod 16. Alternatively to the
spring 24, a further solenoid 22 can obviously be provided so that
in this case a total of two solenoids 22 are provided, which upon
corresponding energisation, adjust the control rod 16 into its
first or second position.
[0030] Viewing FIGS. 1 to 5 it is noticeable that the first control
region 17 is arranged on the longitudinal end side of the control
rod 16 and at the same time formed pot-like, wherein the spring 24,
which in the present case is embodied as a coil spring, is at least
partly arranged in the first control region 17. By way of this, a
protected arrangement of the spring 24 can be achieved in the
housing 20 and in the direction of the shell opening 21 a protected
arrangement over the first control region 17 can be achieved. A
position sensor 25, for example a Hall sensor, via which a position
of the control rod 16 and thus a position of the two control
regions 17, 18 is detectable can likewise be provided. By way of
this, the exact control position can be transmitted for example to
a motor control in each case.
[0031] The first and/or the second control region 17, 18 can be
embodied as cylindrical control discs. In order to improve a
contact between the control pin 12 and the respective control
region 17, 18, it can be additionally mooted that the first and/or
the second control region 17, 18 comprises a flattened region 26
which serves as contact region for the control pin 12.
[0032] Viewing now the individual control positions of the
adjusting device 11 according to the invention as per FIGS. 5A to
5D it is evident 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 region 19, in which no actuation
of the same through the adjusting device 11, i.e. the first or
second control region 17 or 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
shifted to the left and the control pin 12 enters into contact with
the second control region 18. By way of this, the control pin 12 is
moved downwards and thereby adjusted into the second guide track
15, in the control pin 12 now runs and is shifted in the axial
direction 5 to the left into the neutral region 19 by means of the
guide track 15, as shown according to FIG. 5c. According to FIG.
5d, the control rod 16 is again moved to the right as a result of
which the control pin 12 now enters into contact with the first
control region 17, upon which the same adjusts the control pin 12
into the first guide track 14. Altogether it is evident from FIG.
5a to d that the path of the control rod 16 required for changing
over from the first to the second cam 4, 5 or back is comparatively
short, which likewise contributes towards minimising the
installation space. In addition to this merely a single adjusting
device 11 or a control pin 12 and a guide contour 13 for each
cylinder is required with the valve train 1 according to the
invention. As is evident, furthermore, from FIGS. 1 to 5, the two
control regions 17, 18 have different diameters in order to thereby
compensate for different cam strokes.
[0033] With the valve drive 1 according to the invention and the
internal combustion engine 2 equipped with such according to the
invention, a solution that is simple in design, cost effective and
additionally installation space-optimised for changing over between
different cam profiles can thus be achieved.
* * * * *