U.S. patent application number 14/324195 was filed with the patent office on 2014-10-30 for internal combustion engine valve drive adjustment device.
The applicant listed for this patent is DAIMLER AG. Invention is credited to Thomas Stolk, Alexander VON GAISBERG-HELFENBERG.
Application Number | 20140318485 14/324195 |
Document ID | / |
Family ID | 47557138 |
Filed Date | 2014-10-30 |
United States Patent
Application |
20140318485 |
Kind Code |
A1 |
Stolk; Thomas ; et
al. |
October 30, 2014 |
INTERNAL COMBUSTION ENGINE VALVE DRIVE ADJUSTMENT DEVICE
Abstract
In a device for adjusting a valve drive of a motor vehicle
internal combustion engine having at least one camshaft provided
with first and second cam elements supported in an axially
displaceable manner and each having cam tracks for actuating engine
valves, the first cam elements have a number of cam tracks for
actuating respective valves associated with the first cam elements
and a different number of cam tracks for actuating valves
associated with the second cam elements.
Inventors: |
Stolk; Thomas; (Kirchheim,
DE) ; VON GAISBERG-HELFENBERG; Alexander; (Beilstein,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DAIMLER AG |
Stuttgart |
|
DE |
|
|
Family ID: |
47557138 |
Appl. No.: |
14/324195 |
Filed: |
July 6, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2013/000023 |
Feb 21, 2013 |
|
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|
14324195 |
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Current U.S.
Class: |
123/90.15 |
Current CPC
Class: |
F01L 1/34 20130101; F01L
13/0036 20130101; F01L 2013/0052 20130101 |
Class at
Publication: |
123/90.15 |
International
Class: |
F01L 1/34 20060101
F01L001/34 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 21, 2012 |
DE |
10 2012 003 491.1 |
Claims
1. A device for adjusting a motor vehicle valve drive having at
least one camshaft (10) provided with at least first and second cam
elements (11, 14, 12, 13) arranged on the camshaft in an axially
displaceable manner, and having each at least two different cam
tracks disposed adjacent one another for actuating a particular
valve, the number of cam tracks (15, 16, 17, 18, 19, 20, 21, 22,
23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34) for actuating a
valve of one of the cam elements (11, 14i, 12, 13) and the number
of cam tracks (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
28, 29, 30, 31, 32, 33, 34) for actuating a valve of another of the
cam elements (11, 14i, 12, 13) being different from one
another.
2. The device for adjusting a motor vehicle valve drive according
to claim 1, wherein the cam elements (11, 12, 13, 14) arranged in
an axially displaceable manner in each case have at least two cam
tracks (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
30, 31, 32, 33, 34) per valve for adjusting a valve lift of at
least one valve of a cylinder.
3. The device for adjusting a motor vehicle valve drive according
to claim 1, wherein at least one of the cam elements (12, 13) has
at least one cam track (19, 20, 21, 22, 23, 24, 25, 26) providing
for a valve lift, and has one cam track (31, 32, 33, 34) providing
for zero lift.
4. The device for adjusting a motor vehicle valve drive according
to claim 3, wherein another of the cam elements (11, 14) has at
least one cam track (15, 16, 17, 18, 27, 28, 29, 30) providing for
a valve lift and no zero lift cam track.
5. The device for adjusting a motor vehicle valve drive according
to claim 1, wherein of the first cam elements (11, 14) each has two
cam tracks (15, 16, 17, 18, 27, 28, 29, 30) for activating an
associated valve in each case, and of the second elements (12, 13)
each has three cam tracks (19, 20, 21, 22, 23, 24, 25, 26, 31, 32,
33, 34) for activating each an associated valve.
6. The device for adjusting a motor vehicle valve drive according
to claim 1, wherein the camshaft (10) includes two first and two
second axially displaceable cam elements (11, 12, 13, 14), the two
first cam elements (11, 14) in each case having two cam tracks for
activating a valve, and the two second cam elements (12, 13) in
each having three cam tracks for controlling activation of a
valve.
7. The device for adjusting a motor vehicle valve drive according
to claim 5, wherein the second cam elements (12, 13), which have
each three cam tracks (19, 20, 21, 22, 23, 24, 25, 26, 31, 32, 33,
34) for actuating the respective associated valves have each a zero
lift cam track (32, 33).
8. The device for adjusting a motor vehicle valve drive according
to claim 1, wherein a control unit (35) which is provided for
switching the at least the first and second cam elements (11, 12,
13, 14), independently of one another.
9. The device for adjusting a motor vehicle valve drive according
to claim 8, wherein the control unit (35) is provided for changing
a switching position of at least one of the first and second cam
elements (11, 14i; 12, 13) while maintaining the momentary
switching position of the other cam elements (11, 12, 13, 14) in at
least one operating state.
10. The device for adjusting a motor vehicle valve drive according
to claim wherein, in at least one operating state, at least one of
the cam elements (11, 12, 13, 14) has a cam track providing for a
valve lift different from that of another of the cam elements (11,
12, 13, 14).
Description
[0001] This is a Continuation-In-Part application of pending
international patent application PCT/EP2013/000023 filed Jan. 8,
2013 and claiming the priority of German patent application 10 2012
003 491.1 filed Feb. 21, 2012.
BACKGROUND OF THE INVENTION
[0002] The invention relates to a device for adjusting a motor
vehicle valve drive having at least one camshaft with at least two
cam elements which are axially displaceably supported on the at
least one camshaft.
[0003] A device for adjusting a motor vehicle valve drive having a
camshaft which includes at least two cam elements arranged in an
axially displaceable manner, is known for example from DE 10 2007
037 747 A1.
[0004] It is the principal object of the present invention to
provide a device for adjusting a variable motor vehicle valve drive
train which is particularly variable and, at the same time,
compact.
SUMMARY OF THE INVENTION
[0005] In a device for adjusting a valve drive of a motor vehicle
internal combustion engine having at least one camshaft provided
with first and second cam elements supported in an axially
displaceable manner and each being having cam tracks for actuating
engine valves, the first cam elements have a number of cam tracks
for actuating respective valves associated with the first cam
elements and a different number of cam tracks for actuating valves
associated with the second cam elements.
[0006] Individual cam elements may thus be designed in a
particularly variable manner and with more valve lifts than others,
as a result of which the device for adjusting a motor vehicle valve
train may have a particularly variable design. It is also possible
for example that an additional cam track is a no-lift cam track
provided for example for half of the cam elements, which permits an
operational shutdown of half of the cylinders for a more economical
operation of the engine when not all the cylinders are needed.
[0007] A "camshaft" is understood in particular to mean a shaft
that is provided for activating multiple valves of a motor vehicle
internal combustion engine and for activating a valve of at least
one cam track in each case. It is also conceivable for the camshaft
to be designed as an intake camshaft and provided for activating
intake valves, or it is also possible for the camshaft to be
designed as an exhaust camshaft for activating exhaust valves. A
"cam element" is understood in particular to mean an element which
is mounted on a camshaft in a rotationally fixed manner, and which,
for operating a valve, is provided for directly or indirectly
acting on the valve in question with at least one lift. The term
"in a rotationally fixed manner" is understood in particular to
mean a connection that transmits a torque and/or a rotational
motion unchanged. The term "axial" is understood in particular to
mean axial in relation to a main axis of rotation of the cam
element. The term "axially displaceable" is understood in
particular to mean that the cam element is displaceable on the
camshaft, parallel to the main axis of rotation of the cam element,
between at least two working positions. A "cam track" is understood
in particular to mean an area of the cam element, extending on the
periphery of the cam element, which forms a valve activation curve
for activating a valve and/or which defines the valve activation.
The term "at least two cam elements" is understood in particular to
mean that the device for adjusting a motor vehicle valve train
includes at least two cam elements, or also, depending on the
number of cylinders in the motor vehicle internal combustion
engine, includes three cam elements, four cam elements, five cam
elements, six cam elements, eight cam elements, or some other
number of cam elements that appears meaningful to one skilled in
the art.
[0008] It is further proposed that the cam elements arranged in an
axially displaceable manner in each case have at least two cam
tracks per valve for adjusting a valve lift of at least one valve
of a cylinder. The device for adjusting a motor vehicle valve train
may thus have a particularly advantageous design. A "valve lift" is
understood in particular to mean a movement of the valve which is
triggered by the cam tracks of the cam elements, in which the valve
preferably lifts from its valve seat and thus opens up a flow cross
section. The term "adjusting a valve lift" is understood in
particular to mean a switchover between two cam tracks which define
an activation of the at least one valve.
[0009] It is further proposed that at least one of the cam elements
has at least one cam track providing for a valve lift, and a cam
track providing for a zero lift.
[0010] A particularly advantageous cylinder switching-off function
may thus be provided. A "zero lift" is understood in particular to
mean that a valve which is activated with zero lift and which over
a complete revolution of the cam element has a constant valve lift
preferably remains in its valve seat, and a flow cross section of
the valve thus remains blocked over the entire period of time in
which the zero lift track is engaged. In the process, over a
complete revolution of the cam element in question the cam track
having a zero lift preferably remains free of contact with the
corresponding valve and does not contact it. The valve in question
remains inactivated while a cam element having a zero lift is
engaged.
[0011] It is further proposed that another of the cam elements
exclusively has at least one cam track with a valve lift. The cam
element in question may thus have a particularly advantageous and
compact design, as the result of which the overall device for
adjusting a motor vehicle valve train may be compact.
[0012] It is further proposed that one of the at least two cam
elements has two cam tracks for activating a particular valve and
another of the at least two cam elements has three cam tracks for
activating a particular valve. The device for adjusting a motor
vehicle valve train may thus have a particularly variable
design.
[0013] It is further proposed that the camshaft includes four
axially displaceable cam elements with two cam elements in each
case having two cam tracks for activating a valve, and the other
two cam elements in each case having three cam tracks for
activating a valve. A particularly advantageous device for
adjusting a motor vehicle valve train for a four-cylinder internal
combustion engine in a motor vehicle may be provided in this
way.
[0014] It is further proposed that the cam element, which has three
cam tracks in each case, has a zero lift track. The cylinder
switching-off function may thus be integrated into the device for
adjusting a motor vehicle valve train particularly well and in a
simple manner.
[0015] It is further proposed that the device for adjusting a motor
vehicle valve train has a control unit which is provided for
switching the at least two cam elements, at least in part,
independently of one another. The cam elements may thus be switched
in a particularly advantageous manner, and the device for adjusting
a motor vehicle valve train may have a particularly variable
design. A "control unit" is understood in particular to mean a unit
having at least one control device. A "control device" is
understood in particular to mean a unit having a processor unit and
a memory unit, and having an operating program stored in the memory
unit. In principle, the control unit may have multiple
interconnected control devices which are preferably provided for
communicating with one another via a bus system, in particular a
CAN bus system. The term "provided" is understood in particular to
mean specially programmed, designed, and/or equipped. The term
"switch, at least in part, independently of one another" is
understood in particular to mean that a cam element may be switched
in an operating state, regardless of whether the other cam elements
are switched. For switching the cam elements, this may involve the
same actuator, which may switch the cam elements individually and
independently of one another. Switching of all cam elements over a
period of less than 10 camshaft revolutions is understood in
particular to mean dependent switching of the cam elements which is
not independent in the sense of separately switchable cam
elements.
[0016] It is further proposed that the control unit is provided for
changing a switching position of at least one of the cam elements
and to maintain a switching position of at least one other cam
element, in at least one operating state. A cam element may thus be
switched independently of the other cam element in a particularly
advantageous manner. A "switching position of a cam element" is
understood in particular to mean a defined position of the cam
element which the cam element assumes after completion of a
switching operation, and in which a defined cam track is engaged
with the valve in question. The term "change a switching position"
is understood in particular to mean that a cam element is switched
from one switching position into another switching position. The
term "maintain a switching position" is understood in particular to
mean that the switching position of the cam element remains the
same, and in particular there is no switching into another
switching position.
[0017] It is further proposed that in at least one operating state
at least one of the cam elements is engaged with a cam track which
triggers a different valve lift than another of the cam elements.
The motor vehicle internal combustion engine may thus be operated
in a particularly variable manner.
[0018] The invention will become more readily apparent from the
following description of a particular embodiment with reference to
the accompanying drawings. The drawings, the description, and the
claims contain numerous features in combination. Those skilled in
the art will also advantageously consider the features individually
and combine them into further meaningful combinations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 shows a schematic illustration of a device according
to the invention for adjusting a motor vehicle valve drive; and
[0020] FIG. 2 shows a characteristic map of the device according to
the invention for adjusting a motor vehicle valve drive, the
characteristic map being divided into various operating ranges.
DESCRIPTION OF A PARTICULAR EMBODIMENT OF THE INVENTION
[0021] FIG. 1 shows a device according to the invention for
adjusting a motor vehicle valve train. The device for adjusting a
motor vehicle valve drive is part of a motor vehicle internal
combustion engine 51, not illustrated in detail. The motor vehicle
internal combustion engine 51 is part of a motor vehicle, and has
four cylinders. In principle, it is also conceivable for the motor
vehicle internal combustion engine 51 to have a different number of
cylinders that appears meaningful to one skilled in the art. For
each cylinder, the motor vehicle internal combustion engine 51 has
for example two valves in the form of intake valves, and two valves
in the form of exhaust valves. In principle, it is also conceivable
for the motor vehicle internal combustion engine 61 to have only
one intake valve and one exhaust valve for each cylinder, or some
other number of intake and/or exhaust valves that appears
meaningful to one skilled in the art. The device for adjusting a
motor vehicle valve train has a camshaft 10 in the form of an
intake camshaft, which is provided for activating the valves intake
valves, and a camshaft 10, not illustrated in greater detail, which
is an exhaust camshaft and which is provided for activating the
exhaust valves. For reasons of clarity, only the camshaft 10 which
is an intake camshaft is described below. In principle, an exhaust
camshaft may have essentially the same design as the camshaft 10
described below which is an intake camshaft. The intake camshaft 10
and the exhaust camshaft may act with different lifts on the valves
which they activate; the lifts may differ in their maximum lift as
well as in a lift characteristic. The camshaft 10 is rotatable
supported in a cylinder head of the motor vehicle internal
combustion engine 51.
[0022] The camshaft 10 includes four cam elements 11, 12, 13, 14
arranged in an axially displaceable manner. The first cam element
11 is associated with a first cylinder and the corresponding
valves. The second cam element 12 is associated with a second
cylinder and the corresponding valves. The third cam element 13 is
associated with a third cylinder and the corresponding valves. The
fourth cam element 14 is associated with a fourth cylinder and the
corresponding valves. The axially displaceable cam elements 11, 12,
13, 14 are provided for activating and adjusting a valve lift of
two valves of a cylinder in each case. The cam elements 11, 12, 13,
14 are connected in a rotationally fixed manner to the camshaft 10
via a positive fit, not illustrated in greater detail. The cam
elements 11, 12, 13, 14 are displaceable in an axial direction
which extends parallel to a main axis of rotation 36 of the
camshaft 10, in principle, it is also conceivable for the cam
elements 11, 12, 13, 14 to be connected to the camshaft 10 in some
other way that appears meaningful to one skilled in the art.
[0023] The number of cam tracks 15, 16, 17, 18, 19, 20, 21, 22, 23,
24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34 for activating a valve
of one of the cam elements 11, 12, 13, 14 and the number of cam
tracks 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
30, 31, 32, 33, 34 for activating a valve of another of the cam
elements 11, 12, 13, 14 are different from one another. The first
cam element 11, which is arranged in an axially displaceable
manner, and the fourth axially displaceable cam element 14 for
adjusting a valve lift of a valve of a cylinder in each case have
two cam tracks 15, 16, 17, 18, 27, 28, 29, 30 per valve. The first
cam element 11 and the fourth element 14 in each case have two
first cam tracks 15, 17, 27, 29 and two second cam tracks 16, 18,
28, 30. Each first cam track 15, 17, 27, 29 and each second cam
track 16, 18, 28, 30 are associated with the same valve of a
cylinder, and have different valve lifts and lift characteristics.
The first cam tracks 15, 17, 27, 29 and the second cam tracks 16,
18, 28, 30, which in each case are associated with the same valve
of the particular cylinder, are adjacently situated in each case on
the corresponding cam element 11, 14. The first cam tracks 15, 17,
27, 29 of the cam elements 11, 14 are provided for a small valve
lift. The second cam tracks 16, 18, 28, 30 of the cam elements 11,
14 are provided for a large valve lift. The first cam tracks 15,
17, 27, 29, which are provided for a small valve lift, have a
smaller maximum distance from the main axis of rotation 36 of the
camshaft 10 than the second cam tracks 16, 18, 28, 30, which are
provided for a large lift. The cam elements 11, 14 in each case
have a different cross section in an area of the first cam tracks
15, 17, 27, 29 than in an area of the second cam tracks 16, 18, 28,
30.
[0024] The second cam element 12 and the third cam element 13 in
each case have three cam tracks 19, 20, 21, 22, 23, 24, 25, 26, 31,
32, 33, 34 per valve for adjusting a valve lift of a valve of the
associated cylinder. The second cam element 12 and the third cam
element 13 in each case have two first cam tracks 19, 21, 23, 25,
two second cam tracks 20, 22, 24, 26, and two third cam tracks 31,
32, 33, 34. Each first cam track 19, 21, 23, 25, each second cam
track 20, 22, 24, 26, and each third cam track 31, 32, 33, 34 are
in each case associated with the same valve of a cylinder, and have
different valve lifts and lift characteristics. All three cam
tracks 19, 20, 21, 22, 23, 24, 25, 26, 31, 32, 33, 34 are
adjacently situated, and in each case adjoin one another directly.
The first cam tracks 19, 21, 23, 25 in each case are situated
between the third cam tracks 31, 32, 33, 34 and the second cam
tracks 20, 22, 24, 26. The first cam tracks 19, 21, 23, 25 of the
second cam element 12 and of the third cam element 13 have the same
design as the first cam tracks 15, 17, 27, 29 of the first cam
element 11 and of the fourth cam element 14, and are provided for a
small valve lift. The second cam tracks 20, 22, 24, 26 of the
second and third cam elements 12, 13, respectively, have the same
design as the second cam tracks 16, 18, 28, 30 of the first and
fourth cam elements 11, 14, respectively, and are provided for a
large valve lift. The third cam tracks 31, 32, 33, 34 of the second
cam element 12 and of the third cam element 13 have a zero lift.
The third cam tracks 31, 32, 33, 34 of the second and third cam
elements 12, 13, respectively, do not cause activation of the valve
over a complete revolution of the cam elements 12, 13. The third
cam tracks 31, 32, 33, 34 have a maximum distance from the main
axis of rotation 36 of the camshaft 10 that is smaller than that of
the first cam tracks 19, 21, 23, 25. The third cam tracks 31, 32,
33, 34 have no contact with the associated valve during a complete
revolution of the cam element 12, 13. The third cam tracks 31, 32,
33, 34 of the cam elements 12, 13 do not activate the valves, as
the result of which the corresponding cylinder is not charged with
a fuel-air mixture, and therefore cannot be ignited. While the
third cam tracks 31, 32, 33, 34 of a cam element 12, 13 are
engaged, the corresponding cylinder is switched off and generates
no drive torque. In principle, it is also conceivable for the third
cam tracks 31, 32, 33, 34 to contact the valve, but not to lift the
valve from its valve seat.
[0025] Other designs of the cam elements 11, 12, 13, 14 are also
conceivable in principle. Thus, for example, it is conceivable that
only one cam element 11, 12, 13, 14 has a different number of cam
tracks 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
30, 31, 32, 33, 34 than the remaining cam elements 11, 12, 13, 14
of the camshaft 10. In principle, however, it is also conceivable
that another number of cam elements 11, 12, 13, 14, which appears
meaningful to one skilled in the art, may have a different number
of cam tracks 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
28, 29, 30, 31, 32, 33, 34. In principle, it is also conceivable
for at least one cam element 11, 12, 13, 14 to have only one cam
track 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
30, 31, 32, 33, 34, or a different number of cam tracks 15, 16, 17,
18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34
which appears meaningful to one skilled in the art, that is greater
than three. In principle, it is also conceivable for at least one
of the cam elements 11, 12, 13, 14 to have at least two cam tracks
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
32, 33, 34 in each case for activating a valve in each case, and
for another of the at least two cam elements 11, 12, 13, 14 to have
at least three cam tracks 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 26, 27, 28, 29, 30, 31, 32, 33, 34 in each case for activating
a valve in each case, whereby none of the cam tracks 15, 16, 17,
18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34
has a zero lift.
[0026] For adjusting the cam elements 11, 12, 13, 14, the device
for adjusting a motor vehicle valve train includes an actuator
device 37, which for adjusting the valve lift is provided for
axially displacing the cam elements of the camshaft 10. The cam
tracks 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
30, 31, 32, 33, 34, which are engaged with the particular valve,
are changed by axial displacement of the cam elements 11, 12, 13,
14. The first cam element 11 and the second cam element 12 each
have a first switching position and a second switching position.
The second cam element 12 and the third cam element 13 have a first
switching position, a second switching position, and a third
switching position. In the first switching position of one of the
cam elements 11, 12, 13, 14, in each case the two first cam tracks
15, 17, 19, 21, 23, 25, 27, 29 of the cam element are engaged, and
activate the corresponding valve of the corresponding cylinder. The
valves of the cylinders having the small valve lift are activated
in the first switching position. In the second switching position
of one of the cam elements 11, 12, 13, 14, in each case the two
second cam tracks 16, 18, 20, 22, 24, 26, 28, 30 of the cam element
11, 12, 13, 14 are engaged and activate the corresponding valve of
the corresponding cylinder. The valves of the cylinders having the
large valve lift are activated in the second switching position.
The third cam tracks 31, 32, 33, 34 of the second cam element 12
and of the third cam element 13 are engaged in each case in the
third switching position. Since the third cam tracks 31, 32, 33, 34
in each case have zero lift and the respective valves remain
inactivated, the corresponding cylinders are switched off in a
third switching position of the second and third cam elements 12,
13, respectively.
[0027] The device for adjusting a motor vehicle valve train
includes a control unit 35. The control unit 35 is part of an
engine control system. In principle, it is also conceivable for the
control unit 35 to be designed as a separate unit. The control unit
35 is provided for switching the at least four cam elements 11, 12,
13, 14 independently of one another. For switching a cam element
11, 12, 13, 14 from one switching position into the other switching
position, the control unit 35 transmits an electrical or electronic
signal to the actuator device 37, which then switches over the
corresponding cam element 11, 12, 13, 14 from one switching
position into the other switching position. The control unit 35 is
provided to change the switching position of one of the cam
elements 11, 12, 13, 14 and to maintain the switching position of
another cam element 11, 12, 13, 14, in at least one operating
state. As a result, the control unit 35 changes the valve lift of
the one cam element 11, 12, 13, 14 from a small to a large valve
lift, from a large to a small valve lift, or from one of the valve
lifts to a zero lift, whereby the valve lift of the other cam
element 11, 12, 13, 14 which is not switched over maintains its
previous small valve lift, large valve lift, or zero lift. It is
conceivable for the control unit 35 to switch only one cam element
11, 12, 13, 14, two cam elements 11, 12, 13, 14, three cam elements
11, 12, 13, 14, or all four cam elements 11, 12, 13, 14 at least
essentially at the same time, in a defined operating state. The
actuator device 37 may result in temporal differences, which
preferably amount to only up to two camshaft revolutions.
[0028] At least one of the four cam elements 11, 12, 13, 14 in at
least one operating state is engaged with a cam track 15, 16, 17,
18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34
which triggers a different valve lift than a cam track 15, 16, 17,
18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34
that is engaged with another of the four cam elements 11, 12, 13,
14. Various cam elements 11, 12, 13, 14 in an operating state are
engaged with cam tracks 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
26, 27, 28, 29, 30, 31, 32, 33, 34 which for the corresponding
valves trigger various valve lifts or zero lift. Thus, for example,
in one operating state at least one of the four cam elements 11, 14
is in the first switching position, and thus is engaged with a cam
track 15, 17, 27, 29 which triggers a small valve lift, while at
least one other of the four cam elements 12, 13 is in the third
switching position, i.e., is engaged with the third cam track 31,
32, 33, 34 which triggers a zero lift.
[0029] The actuator device 37 includes a central actuator 38 which
is provided for switching all four cam elements. In principle, it
is also conceivable for the actuator device 37 to include two
actuators 38, each of which is provided for switching two of the
four cam elements 11, 12, 13, 14. In principle, it is also
conceivable that for switching each of the cam elements 11, 12, 13,
14, the actuator device 37 has a separate actuator which in each
case switches only one cam element 11, 12, 13, 14 that is
associated with it. In principle, any other configuration and/or
number of actuators that appears meaningful to one skilled in the
art is conceivable in order to switch the cam elements 11, 12, 13,
14. In addition, actuators that switch only one cam element 11, 12,
13, 14 and actuators that switch multiple cam elements 11, 12, 13,
14 may be combined.
[0030] As illustrated in FIG. 2, the device for adjusting a motor
vehicle valve train has four different operating ranges 39, 40, 41,
42. The speed of the motor vehicle internal combustion engine 51 is
plotted on the abscissa 52, and the power of the motor vehicle
internal combustion engine 51 is plotted on the ordinate 53 in the
diagram in FIG. 2. In principle, it is also conceivable for the
device for adjusting a motor vehicle valve train to have some other
number of operating ranges 39, 40, 41 42 that appears meaningful to
one skilled in the art. The various operating ranges 39, 40, 41, 42
are associated with a power-speed range of the motor vehicle
internal combustion engine 51. Below a defined first power 43 and
below a defined first speed 44, the motor vehicle internal
combustion engine 51 is in a first operating range 39. The first
operating range 39 is designed as a central switching-off operating
range. Above the defined first power 43 and below a second defined
power 45, and above the first defined speed 44 and below a second
defined speed 46, the motor vehicle internal combustion engine 51
is in a second operating range 40. The second operating range 40 is
likewise designed as a central switching-off operating range. The
third operating range 41 is delimited by the second defined power
45, the second defined speed 46, a third defined power 47, and a
third defined speed 48. The fourth operating range 42 is delimited
by the third defined power 47, the third defined speed 48, a
maximum power 49, and a maximum speed 50. The various powers and
speeds are defined as a function of the corresponding motor vehicle
internal combustion engine 51, and vary over ranges which appear
meaningful to one skilled in the art.
[0031] The device for adjusting a motor vehicle valve train has a
different combination of switching positions of the cam elements
11, 12, 13, 14 in each operating range 39, 40, 41, 42. In the first
operating range 39 designed as a central switching-off operating
range, the first cam element 11 and the fourth cam element 14 are
each in their first switching position, and in each case activate
the particular valves having the small valve lift. In the first
operating range, the second cam element 12 and the third cam
element 13 are each in the third switching position, and activate
the particular valves having a zero lift.
[0032] In the second operating range 40 designed as a central
switching-off operating range, the first cam element 11 and the
fourth cam element 14 are each in their second switching position,
and in each case activate the particular valves having the large
valve lift. In the second operating range 40, the second cam
element 12 and the third cam element 13 are in the third switching
position, and activate the particular valves having a zero lift For
this purpose, during a transition from the first operating range 39
into the second operating range 40, the control (and regulation)
unit 35 switches the first cam element 11 and the fourth cam
element 14 in each case from the first switching position into the
second switching position by means of the actuator device 37, and
thus changes the valve lifts of the valves of the first and fourth
cylinders which are activated by the first cam element 11 and the
fourth cam element 14, respectively, from the small valve lift to
the large valve lift.
[0033] In the third operating range 41, all four cam elements 11,
12, 13, 14 are switched into the same switching position. In the
third operating range 41, the cam elements 11, 12, 13, 14 are each
in their first switching position, and in each case activate the
particular valves having a small valve lift. For this purpose,
during a transition from the second operating range 40 into the
third operating range 41, the control (and regulation) unit 35
switches the first cam element 11 and the fourth cam element 14 in
each case from the second switching position into the first
switching position by means of the actuator device 37, and thus
changes the valve lifts of the valves of the first and fourth
cylinders which are activated by the first cam element 11 and the
fourth cam element 14, respectively, from the large valve lift to
the small valve lift. In addition, during the transition from the
second operating range 40 into the third operating range 41, the
control (and regulation) unit 35 switches the second cam element 12
and the third cam element 13 in each case from the third switching
position into the first switching position by means of the actuator
device 37, and thus changes the valve lifts of the valves of the
second and third cylinders which are activated by the second cam
element 12 and the third cam element 13, respectively, from zero
lift to the small valve lift.
[0034] All four cam elements 11, 12, 13, 14 are switched into the
same switching position in the fourth operating range 42. In the
fourth operating range 41, all cam elements 11, 12, 13, 14 are in
each case switched into their second switching position, and in
each case activate the particular valves having a large valve lift.
For this purpose, during a transition from the third operating
range 41 into the fourth operating range 42, the control (and
regulation) unit 35 switches the first cam element 11, the second
cam element 12, the third cam element 13, and the fourth cam
element 14 in each case from the first switching position into the
second switching position by means of the actuator device 37, and
thus changes the valve lifts of the valves of the first, second,
third, and fourth cylinders which are activated by the first cam
element 11, the second cam element 12, the third cam element 13,
and the fourth cam element 14, respectively, from the small valve
lift to the large valve lift.
[0035] In principle, it is likewise conceivable for individual
operating ranges 39, 40, 41, 42 to be skipped, in that, for
example, switching the corresponding cam element 11, 12, 13, 14 is
temporarily skipped and is not carried out until, for example, a
transition into the corresponding next operating range 39, 40, 41,
42 or the operating range which follows it. It is conceivable for
the control unit 35 to skip individual operating ranges 39, 40, 41,
42 or to skip switching of the corresponding cam elements 11, 12,
13, 14 into the individual operating ranges, based on engine
parameters such as load torque or the like.
[0036] In principle, of course, any other switching of the cam
elements 11, 12, 13, 14 into the various operating ranges 39, 40,
41, 42 is conceivable which appears meaningful to one skilled in
the art. Thus, for example, it is conceivable that in the third
operating range 41, the first cam element 11 and the fourth cam
element 14 are switched into the first switching position, and the
second cam element 12 and the third cam element 13 are switched
into their second switching position.
[0037] The actuator device 37 has mechanical encoding which
specifies a defined switching sequence of the cam elements 11, 12,
13, 14. Due to the mechanical encoding of the actuator device 37, a
switching sequence of the cam elements 11, 12, 13, 14 is
predetermined, and switching of the individual cam elements 11, 12,
13, 14 always follows a set pattern. The individual switching
positions of the individual cam elements 11, 12, 13, 14 in the
various operating ranges 39, 40, 41, 42 are specified by the
mechanical encoding. In a next operating range 39, 40, 41, 42 the
switching position of the cam element 11, 12, 13, 14 is always
followed by the same switching position. For switching from the one
operating range 39, 40, 41, 42 into an adjacent operating range 39,
40, 41, 42, the control (and regulation) unit 35 outputs only one
signal for the switching to the actuator device 37, and correct
switching of the cam elements 11, 12, 13, 14 is predetermined by
the mechanical encoding. Faulty switching or an absence of
switching of one of the cam elements 11, 12, 13, 14 is ruled out.
Defined switching positions of the cam elements 11, 12, 13, 14 are
always present,
[0038] The actuator device 37 is provided for switching the cam
elements 11, 12, 13, 14 as a function of at least one operating
parameter of the motor vehicle internal combustion engine 51. Upon
exceeding a defined speed 44, 46, 48 or a defined power 43, 45, 47
of the motor vehicle internal combustion engine 51 which in each
case separate two operating ranges 39, 40, 41, 42 from one another,
the control unit 35 outputs a signal for switching the appropriate
cam elements 11, 12, 13, 14 by means of the actuator device 37.
[0039] The above description relates only to the design of the
device for adjusting a motor vehicle valve train for a motor
vehicle internal combustion engine 51 having four cylinders. A
design of the device for adjusting a motor vehicle valve train for
a motor vehicle internal combustion engine 51 having a different
number of cylinders, for example two cylinders, three cylinders,
six cylinders, or eight cylinders, is essentially the same. A
different number of cylinders results in an adjusted number of
axially displaceable cam elements 11, 12, 13, 14, and thus results
in a number of possible combinations of the switching position of
the various cam elements 11, 12, 13, 14. Also for a device for
adjusting a motor vehicle valve train for a motor vehicle internal
combustion engine 51 having more or fewer cylinders, switching of
the cam elements 11, 12, 13, 14, individually or in groups, which
may be adjusted to the number of cam elements 11, 12, 13, 14 as
described above, takes place as described in the exemplary
embodiment above. A design of the actuator device 37 and the number
and/or configuration of actuators 38 may be provided in a manner
that appears meaningful to one skilled in the art.
LIST OF REFERENCE NUMERALS
[0040] 10 Camshaft [0041] 11 Cam element [0042] 12 Cam element
[0043] 13 Cam element [0044] 14 Cam element [0045] 15 Cam track
[0046] 16 Cam track [0047] 17 Cam track [0048] 18 Cam track [0049]
19 Cam track [0050] 20 Cam track [0051] 21 Cam track [0052] 22 Cam
track [0053] 23 Cam track [0054] 24 Cam track [0055] 25 Cam track
[0056] 26 Cam track [0057] 27 Cam track [0058] 28 Cam track [0059]
29 Cam track [0060] 30 Cam track [0061] 31 Cam track [0062] 32 Cam
track [0063] 33 Cam track [0064] 34 Cam track [0065] 35 Control
and/or regulation unit [0066] 36 Main axis of rotation [0067] 37
Actuator device [0068] 38 Actuator [0069] 39 Operating range [0070]
40 Operating range [0071] 41 Operating range [0072] 42 Operating
range [0073] 43 First power [0074] 44 First speed [0075] 45 Second
power [0076] 46 Second speed [0077] 47 Third power [0078] 48 Third
speed [0079] 49 Maximum power [0080] 50 Maximum speed [0081] 51
Motor vehicle internal combustion engine [0082] 52 Abscissa [0083]
53 Ordinate
* * * * *