U.S. patent application number 14/374405 was filed with the patent office on 2014-11-13 for internal combustion engine valve train device.
The applicant listed for this patent is Daimler AG. Invention is credited to Thomas Stolk, Alexander Von Gaisberg-Helfenberg.
Application Number | 20140331949 14/374405 |
Document ID | / |
Family ID | 47710081 |
Filed Date | 2014-11-13 |
United States Patent
Application |
20140331949 |
Kind Code |
A1 |
Stolk; Thomas ; et
al. |
November 13, 2014 |
Internal Combustion Engine Valve Train Device
Abstract
An internal combustion engine valve train device of a motor
vehicle, includes at least one exhaust valve actuating unit and at
least one intake valve actuating unit, and an operating mode
switching unit that is provided for switching the exhaust valve
actuating unit into an exhaust gas recirculation mode in order to
adjust an internal exhaust gas recirculation. The operating mode
switching unit is provided for also switching the intake valve
actuating unit into an exhaust gas recirculation mode in order to
adjust an internal exhaust gas recirculation.
Inventors: |
Stolk; Thomas; (Kirchheim,
DE) ; Von Gaisberg-Helfenberg; Alexander; (Beilstein,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Daimler AG |
Stuttgart |
|
DE |
|
|
Family ID: |
47710081 |
Appl. No.: |
14/374405 |
Filed: |
January 8, 2013 |
PCT Filed: |
January 8, 2013 |
PCT NO: |
PCT/EP2013/000024 |
371 Date: |
July 24, 2014 |
Current U.S.
Class: |
123/90.15 |
Current CPC
Class: |
F01L 1/34 20130101; Y02T
10/18 20130101; F01L 13/0036 20130101; F01L 2013/0052 20130101;
Y02T 10/12 20130101; F01L 2800/10 20130101; F02D 13/0203 20130101;
F02D 13/0265 20130101 |
Class at
Publication: |
123/90.15 |
International
Class: |
F01L 1/34 20060101
F01L001/34 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 25, 2012 |
DE |
10 2012 001 316. |
Claims
1-11. (canceled)
12. An internal combustion engine valve train device of a motor
vehicle, comprising: at least one exhaust valve actuating unit; at
least one intake valve actuating unit; and an operating mode
switching unit structurally configured to switch the exhaust valve
actuating unit into an exhaust gas recirculation mode to adjust an
internal exhaust gas recirculation, the intake valve actuating unit
into an exhaust gas recirculation mode in order to adjust an
internal exhaust gas recirculation, wherein the intake valve
actuating unit has at least one intake cam which includes at least
one first cam track for a normal mode and a second cam track for
the exhaust gas recirculation mode.
13. The internal combustion engine valve train device of claim 12,
wherein the second cam track of the at least one intake cam differs
from the at least one first cam track of the at least one intake
cam by at least one valve actuation parameter.
14. The internal combustion engine valve train device of claim 12,
wherein the second cam track of the at least one intake cam is
configured to set an intake valve opening phase at least
essentially outside an exhaust valve opening phase.
15. The internal combustion engine valve train device of claim 12,
wherein the second cam track of the at least one intake cam
provides a valve actuation parameter as a lift height that differs
from a lift height of the first cam track of the at least one
intake cam.
16. The internal combustion engine valve train device of claim 15,
wherein the lift height of the second cam track of the at least one
intake cam is smaller than the lift height of the first cam track
of the at least one intake cam.
17. The internal combustion engine valve train device of claim 12,
wherein the second cam track of the at least one intake cam
provides a valve actuation parameter that is an opening duration
and that differs from an opening duration of the first cam track of
the at least one intake cam.
18. The internal combustion engine valve train device of claim 17,
wherein the opening duration of the second cam track of the at
least one intake cam, is shorter than the opening duration of the
first cam track of the at least one intake cam.
19. The internal combustion engine valve train device of claim 12,
wherein the exhaust valve actuating unit has at least one exhaust
cam, with at least one cam track for the exhaust gas recirculation
mode that provides at least two valve actuation parameters for a
lift height that differ from a lift height of the second cam track
of the at least one intake cam.
20. The internal combustion engine valve train device of claim 19,
wherein the lift height of the second cam track of the at least one
intake cam is smaller than at least one of the two valve actuation
parameters of the cam track of the at least one exhaust cam.
21. The internal combustion engine valve train device of claim 12,
wherein the operating mode switching unit has at least one switch
gate configured to convert a rotary movement into an axial
movement, at least for switching the exhaust gas recirculation
mode.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
[0001] Exemplary embodiments of the invention relate to an internal
combustion engine valve train device.
[0002] German patent document DE 10 2010 051 130 A1 discloses an
internal combustion engine valve train device of a motor vehicle
having at least one exhaust valve actuating unit and at least one
intake valve actuating unit, and an operating mode switching unit
that is provided for switching the exhaust valve actuating unit
into an exhaust gas recirculation mode in order to adjust an
internal exhaust gas recirculation.
[0003] Exemplary embodiments of the present invention are directed
to reducing fuel consumption of a motor vehicle which has the
internal combustion engine valve train device.
[0004] Exemplary embodiments of the present invention are directed
to an internal combustion engine valve train device of a motor
vehicle, having at least one exhaust valve actuating unit and at
least one intake valve actuating unit, and an operating mode
switching unit that is provided for switching the exhaust valve
actuating unit into an exhaust gas recirculation mode in order to
adjust an internal exhaust gas recirculation.
[0005] In accordance with the invention the operating mode
switching unit is provided for additionally switching the intake
valve actuating unit into an exhaust gas recirculation mode in
order to adjust an internal exhaust gas recirculation. In this way,
an intake valve actuation and an exhaust valve actuation may be
adapted specifically to the exhaust gas recirculation, as the
result of which a particularly advantageous internal exhaust gas
recirculation may be achieved. A constant exhaust gas recirculation
quantity in the exhaust gas recirculation mode may be ensured, so
that pollutant emissions may be reduced. In addition, the drive
power for the intake valve actuation and/or the drive power for the
exhaust valve actuation in the exhaust gas recirculation mode may
be reduced, so that the efficiency may be increased. The fuel
consumption of a motor vehicle having the internal combustion
engine valve train device may be reduced in this way. An "exhaust
gas recirculation quantity" should be understood to mean an exhaust
gas quantity that is resupplied to a cylinder by the internal
exhaust gas recirculation for a subsequent combustion operation.
The exhaust valve actuating unit is preferably operable at least in
a normal mode and an exhaust gas recirculation mode. The intake
valve actuating unit is preferably operable at least in a normal
mode and an exhaust gas recirculation mode. An "operating mode
switching unit" should be understood to mean a unit that is
provided for switching between at least two different operating
modes, preferably at least between a normal mode and an exhaust gas
recirculation mode. The operating mode switching unit preferably
switches the exhaust valve actuating unit and/or the intake valve
actuating unit in order to set the corresponding operating mode.
The operating mode switching unit is advantageously provided for
switching a valve actuation characteristic of the exhaust valve
actuating unit and/or of the intake valve actuating unit in
discrete steps. The operating mode switching unit is particularly
preferably provided for functionally bringing at least one intake
valve in contact with one of at least two cam tracks of the intake
valve actuating unit, and/or for functionally bringing at least one
exhaust valve in contact with one of at least two cam tracks of the
exhaust valve actuating unit. An "internal exhaust gas
recirculation" is understood in particular to mean an exhaust gas
recirculation in which exhaust gas from an exhaust tract is
directly resupplied to a cylinder. The term "provided" is
understood in particular to mean specially programmed, equipped,
designed, and/or situated.
[0006] It is further proposed that the intake valve actuating unit
has at least one intake cam which includes at least one first cam
track for a normal mode and a second cam track for the exhaust gas
recirculation mode. The exhaust gas recirculation mode may thus be
set in a particularly advantageous manner. The exhaust valve
actuating unit preferably has at least one exhaust cam which
includes at least one first cam track for the normal mode and a
second cam track for the exhaust gas recirculation mode. An "intake
cam" should be understood to mean an element that is provided for
actuating at least one intake valve, the element for actuating the
intake valve preferably being provided for directly or indirectly
acting on the intake valve with at least one lift. An "exhaust cam"
should be understood to mean an element that is provided for
actuating at least one exhaust valve, the element for actuating the
exhaust valve preferably being provided for directly or indirectly
acting on the exhaust valve with at least one lift. For switching
the operating modes, the at least one intake cam is situated on an
intake cam base shaft so as to be axially displaceable but
rotationally fixed. For switching the operating modes, the at least
one exhaust cam is situated on an exhaust cam base shaft so as to
be axially displaceable but rotationally fixed. A "cam track"
should be understood to mean a portion of a cam provided for
directly actuating a gas exchange valve and/or for picking up by
means of a cam follower for actuating the gas exchange valve. A cam
track preferably has a gas valve actuation curve. The cam track is
preferably designed as an area extending over the periphery of the
intake cam or of the exhaust cam, and which forms the gas valve
actuation curve for actuating the corresponding gas exchange valve
and/or which defines the actuation by providing at least one valve
actuation parameter. The gas exchange valve is advantageously
designed as an intake valve or as an exhaust valve. The gas valve
actuation curve is preferably designed as an intake valve actuation
curve or as an exhaust valve actuation curve.
[0007] In addition, the second cam track of the at least one intake
cam differs from the first cam track of the at least one intake cam
by at least one valve actuation parameter, as the result of which
the intake valve actuation may be specifically adapted to the
internal exhaust gas recirculation. A "valve actuation parameter"
should be understood to mean a parameter provided by a
configuration of the cam track and which defines the actuation of
the corresponding gas exchange valve. The valve actuation parameter
is preferably defined and/or described by the gas valve actuation
curve.
[0008] In particular, it is advantageous when the second cam track
of the at least one intake cam is provided for setting an intake
valve opening phase at least essentially outside an exhaust valve
opening phase. For an at least essentially closed intake valve, an
exhaust gas may thus be drawn back in, as the result of which the
exhaust gas recirculation quantity may be precisely metered. The
second cam track of the at least one intake cam is preferably
provided for keeping at least one intake valve at least largely
closed during an actuation of at least one exhaust valve. The term
"setting an intake valve opening phase outside an exhaust valve
opening phase" should be understood to mean that a shared opening
phase of the intake valve and of the exhaust valve, and/or an
overlap area of an intake valve actuation curve and an exhaust
valve actuation curve, preferably along a crankshaft angle in
degrees, is absent. The term "essentially" should be understood to
mean that within a working cycle, a shared opening phase has a
duration of a maximum of 30 degrees crankshaft, advantageously a
maximum of 15 degrees crankshaft angle, and particularly
advantageously a maximum of 5 degrees crankshaft angle. A overlap
area of the intake valve actuation curve and of the exhaust valve
actuation curve for an intake opening phase for an intake opening
phase that is set essentially outside the exhaust opening phase is
a maximum of 30 degrees crankshaft angle, advantageously a maximum
of 15 degrees crankshaft angle, and particularly advantageously a
maximum of 5 degrees crankshaft angle. A "working cycle" should be
understood to mean the smallest possible recurring circular process
that is divided into at least two subdivided cycles of a piston
movement in a cylinder. A cycle is preferably defined by the piston
movement in one direction from a standstill until the next
standstill, i.e., from one dead center to another dead center. A
cycle advantageously corresponds to one-half revolution of a
crankshaft, i.e., preferably 180 degrees crankshaft angle. A
working cycle advantageously corresponds to two revolutions of the
crankshaft, i.e., preferably 720 degrees crankshaft angle. The
intake valve opening phase and the exhaust valve opening phase are
preferably situated with respect to one another at least
essentially free of overlap, in particular along the crankshaft
angle in degrees.
[0009] Furthermore, it is advantageous when the second cam track of
the at least one intake cam provides a valve actuation parameter
designed as the lift height and which differs from a valve
actuation parameter of the first cam track of the at least one
intake cam, designed as the lift height. The intake valve actuation
may be adapted in a particularly advantageous manner in this way.
The term "valve actuation parameter designed as the lift height"
should be understood to mean a valve actuation parameter which is
defined by a level at a high point of the gas valve actuation
curve.
[0010] In addition, it is advantageous when the valve actuation
parameter of the second cam track of the at least one intake cam,
designed as the lift height, is smaller than the valve actuation
parameter of the first cam track of the at least one intake cam,
designed as the lift height, as the result of which the drive power
for the intake valve actuation in the exhaust gas recirculation
mode may be reduced using a simple design.
[0011] In another embodiment according to the invention, the second
cam track of the at least one intake cam provides a valve actuation
parameter designed as the opening duration and which differs from a
valve actuation parameter of the first cam track of the at least
one intake cam, designed as the opening duration. The intake valve
actuation in the exhaust gas recirculation mode may be optimized in
this way. The term "valve actuation parameter designed as the
opening duration" should be understood to mean a valve actuation
parameter defined by a crankshaft angle range in degrees, in which
a lift of the corresponding gas valve actuation curve is greater
than zero, preferably within a working cycle. The valve actuation
parameter designed as the opening duration preferably defines a
crankshaft angle range in degrees, in which the at least one intake
valve or the at least one exhaust valve is open, preferably within
a working cycle.
[0012] Furthermore, in accordance with exemplary embodiments of the
invention the actuation parameter of the second cam track of the at
least one intake cam, designed as the opening duration, is shorter
than the valve actuation parameter of the first cam track of the at
least one intake cam, designed as the opening duration, as the
result of which the drive power for the intake valve actuation in
the exhaust gas recirculation mode may be further reduced in a
particularly simple manner. In the present context, the term
"shorter" should be understood to mean a shorter opening phase. The
valve actuation parameter, which is provided by the second cam
track of the at least one intake cam and is shorter than the
opening duration, is preferably defined by a gas valve actuation
curve that is narrower than the gas valve actuation curve which
defines the actuation parameter of the at least one intake cam,
designed as the opening duration.
[0013] In addition, the exhaust valve actuating unit has at least
one exhaust cam, with at least one cam track for the exhaust gas
recirculation mode that provides at least two valve actuation
parameters designed as the lift height, and the valve actuation
parameter of the second cam track of the at least one intake cam,
designed as the lift height, differs from both valve actuation
parameters of the cam track of the at least one exhaust cam,
designed as the lift height. In this way, the intake valve
actuation in the exhaust gas recirculation mode may be adapted to
the exhaust valve actuation in the exhaust gas recirculation mode
in a particularly advantageous manner.
[0014] In particular, it is advantageous when the valve actuation
parameter of the second cam track of the at least one intake cam,
designed as the lift height, is smaller than at least one of the
two valve actuation parameters of the cam track of the at least one
exhaust cam, designed as the lift height, as the result of which a
particularly advantageous internal exhaust gas recirculation may be
achieved. The valve actuation parameter of the second cam track of
the at least one intake cam, designed as the lift height, is
preferably larger than one of the two valve actuation parameters of
the cam track of the at least one exhaust cam, designed as the lift
height.
[0015] The operating mode switching unit particularly preferably
has at least one switch gate provided for converting a rotary
movement into an axial movement, at least for switching the exhaust
gas recirculation mode. As a result, particularly advantageous
switching between the normal mode and the exhaust gas recirculation
mode may be achieved. A "switch gate" should be understood to mean
a unit having at least one gate track provided for converting a
rotary movement into an axial adjusting force. A "gate track"
should be understood mean a track for forced guidance of a gate
engagement element at least on one side, preferably on both sides.
The gate track is preferably designed in the form of a web, in the
form of a slot, and/or in the form of a groove. A "gate engagement
element" should be understood to mean an element which in at least
one operating state at least partially engages with the switch gate
and/or at least partially surrounds the switch gate and thus is
preferably in operative connection with the switch gate, as the
result of which the element is forcibly guided by the switch gate.
The gate engagement element is preferably designed in the form of a
shifting shoe which surrounds the web, in the form of a pin which
engages in the slot, and/or in the form of a pin which is guided in
the groove. The switch gate is preferably designed either as a
separate element connected to at least one intake cam or to at
least one exhaust cam in a rotationally and displaceably fixed
manner, or as one piece with the intake cam or with the least one
exhaust cam. The switch gate is advantageously provided for
converting a rotary movement of the at least one intake cam into an
axial movement of the at least one intake cam, and/or for
converting a rotary movement of the at least one exhaust cam into
an axial movement of the at least one exhaust cam, at least for
switching the exhaust gas recirculation mode.
[0016] Additionally, exemplary embodiments of the invention are
directed to a method for adjusting an internal exhaust gas
recirculation of an internal combustion engine valve train device
of a motor vehicle, in particular an internal combustion engine
valve train device according to the invention, in which an exhaust
valve actuating unit and also an intake valve actuating unit are
switched into an exhaust gas recirculation mode in order to adjust
the internal exhaust gas recirculation.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0017] Further advantages result from the following description of
the drawings. The drawings illustrate one exemplary embodiment of
the invention. 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.
[0018] The figures show the following:
[0019] FIG. 1 shows a portion of an internal combustion engine
valve train device, having an exhaust valve actuating unit and an
intake valve actuating unit, and an operating mode switching unit
which switches the exhaust valve actuating unit and the intake
valve actuating unit into an exhaust gas recirculation mode in
order to adjust an internal exhaust gas recirculation; and
[0020] FIG. 2 shows an exhaust valve actuation curve of the exhaust
valve actuating unit which is switched in the exhaust gas
recirculation mode, and an intake valve actuation curve of the
intake valve actuating unit which is switched in the exhaust gas
recirculation mode.
DETAILED DESCRIPTION
[0021] FIG. 1 shows an internal combustion engine valve train
device of a motor vehicle. For providing a drive torque, the motor
vehicle has an internal combustion engine, not illustrated in
greater detail, having exhaust valves and intake valves that are
actuated by the internal combustion engine valve train device
during operation of the internal combustion engine. The internal
combustion engine valve train device has an exhaust valve actuating
unit 10 for actuating the exhaust valves, and has an intake valve
actuating unit 11 for actuating the intake valves. For switching
between two operating modes of the internal combustion engine, the
internal combustion engine valve train device has an operating mode
switching unit 12, which switches the exhaust valve actuating unit
10 as well as the intake valve actuating unit 11 in order to set
the appropriate operating mode. In this exemplary embodiment, the
internal combustion engine has two operating modes, one operating
mode being designed as a normal mode and the other being designed
as an exhaust gas recirculation mode. The operating mode switching
unit 12 switches the exhaust gas recirculation mode in order to
adjust an internal exhaust gas recirculation. In principle, the
internal combustion engine may also have other operating modes. The
motor vehicle is designed as a passenger vehicle.
[0022] For setting the normal mode, the exhaust valve actuating
unit 10 and the intake valve actuating unit 11 each have a normal
mode. For setting the exhaust gas recirculation mode, the exhaust
valve actuating unit 10 and the intake valve actuating unit 11 each
have an exhaust gas recirculation mode. The exhaust valve actuating
unit 10 and the intake valve actuating unit 11 are each operable in
a first operating mode and in a second operating mode. The normal
mode and the exhaust gas recirculation mode of the exhaust valve
actuating unit 10 differ in the exhaust valve actuation curves. The
normal mode and the exhaust gas recirculation mode of the intake
valve actuating unit 11 differ in the intake valve actuation
curves.
[0023] For adjusting the internal exhaust gas recirculation, the
operating mode switching unit 12 switches the exhaust valve
actuating unit 10 and the intake valve actuating unit 11 into the
exhaust gas recirculation mode, starting from the normal mode. For
setting a normal mode, i.e., an operation without internal exhaust
gas recirculation, the operating mode switching unit 12 switches
the exhaust valve actuating unit 10 and the intake valve actuating
unit 11 into the normal mode, starting from the exhaust gas
recirculation mode. The operating mode switching unit 12 switches
the exhaust valve actuating unit 10 and the intake valve actuating
unit 11 simultaneously into the appropriate operating mode. In
principle, the operating mode switching unit 12, the exhaust valve
actuating unit 10, and the intake valve actuating unit 11 may
switch into the appropriate operating mode in a staggered
manner.
[0024] The intake valve actuating unit 11 has multiple intake cams
for actuating the intake valves, only the intake cams 13, 14 being
illustrated for the sake of clarity. For providing the normal mode
and the exhaust gas recirculation mode, the intake cams 13, 14 each
have a first cam track 17 for the normal mode and a second cam
track 18 for the exhaust gas recirculation mode. The first cam
track 17 of the intake cams 13, 14 has an intake valve actuation
curve for the normal mode, and the second cam track 18 of the
intake cams 13, 14 has an intake valve actuation curve 37 for the
exhaust gas recirculation mode. The intake valve actuation curve
for the normal mode and the intake valve actuation curve 37 for the
exhaust gas recirculation mode differ from one another. The intake
valve actuation curve 37 for the exhaust gas recirculation mode has
a lift that differs from a lift of the intake valve actuation curve
for the normal mode. The second cam track 18 of the intake cams 13,
14 differs from the first cam track 17 of the corresponding intake
cams 13, 14 in two valve actuation parameters 19, 20.
[0025] The second cam track 18 of the intake cams 13, 14 provides a
valve actuation parameter 19 designed as the lift height, and which
differs from a valve actuation parameter of the first cam track 17
of the intake cams 13, 14, designed as the lift height. The
actuation parameter 19 of the second cam track 18 of the intake
cams 13, 14, designed as the lift height valve, is smaller than the
valve actuation parameter of the first cam track 17 of the intake
cams 13, 14, designed as the lift height. The lift of the intake
valve actuation curve 37 for the exhaust gas recirculation mode is
smaller than the lift of the intake valve actuation curve for the
normal mode. The valve actuation parameter of the first cam track
17 of the intake cams 13, 14, designed as the lift height, is
designed as a maximum lift of the intake valve actuation curve for
the normal mode. The valve actuation parameter 19 of the second cam
track 18 of the intake cams 13, 14, designed as the lift height, is
designed as a maximum lift of the intake valve actuation curve 37
for the exhaust gas recirculation mode.
[0026] The second cam track 18 of the intake cams 13, 14 also
provides a valve actuation parameter 20 designed as the opening
duration and which differs from a valve actuation parameter of the
first cam track 17 of the intake cams 13, 14, designed as the
opening duration. The valve actuation parameter 20 of the second
cam track 18 of the intake cams 13, 14, designed as the opening
duration, is shorter than the valve actuation parameter of the
first cam track 17 of the intake cams 13, 14, designed as the
opening duration. The lift of the intake valve actuation curve 37
for the exhaust gas recirculation mode is narrower than the lift of
the intake valve actuation curve for the normal mode. The valve
actuation parameter 20 of the second cam track 18 of the intake
cams 13, 14, designed as the opening duration, sets an intake valve
opening phase 21 of the intake valves that is shorter than an
intake valve opening phase of the intake valves set by the valve
actuation parameter of the first cam track 17 of the intake cams
13, 14, designed as the opening duration.
[0027] The intake valve actuating unit 11 has an intake cam element
38 for accommodating the intake cams 13, 14. The intake cams 13, 14
are each situated on the intake cam element 38 in a rotationally
and displaceably fixed manner. For accommodating the intake cam
element 38, the intake valve actuating unit 11 has an intake cam
base shaft 39 which is in drive connection with a crankshaft of the
internal combustion engine. The intake cam element 38 is situated
on the intake cam base shaft 39 so as to be rotationally fixed but
axially displaceable. The intake valve actuating unit 11 is
designed as an intake camshaft unit.
[0028] For actuating the exhaust valves, the exhaust valve
actuating unit 10 has multiple exhaust cams, only the exhaust cams
24, 25 being illustrated for the sake of clarity. For providing the
normal mode and the exhaust gas recirculation mode, the exhaust
cams 24, 25 each have a first cam track 40 for the normal mode and
a second cam track 28 for the exhaust gas recirculation mode. The
first cam track 40 of the exhaust cams 24, 25 has an exhaust valve
actuation curve for the normal mode, and the second cam track 28 of
the exhaust cam 24, 25 has an exhaust valve actuation curve 41 for
the exhaust gas recirculation mode. The exhaust valve actuation
curve for the normal mode and the exhaust valve actuation curve 41
for the exhaust gas recirculation mode differ from one another. The
exhaust valve actuation curve 41 for the exhaust gas recirculation
mode has a lift that differs from a lift of the exhaust valve
actuation curve for the normal mode. The second cam track 28 of the
exhaust cams 24, 25 differs from the first cam track 40 in the
number of lifts.
[0029] The first cam track 40 of the exhaust cams 24, 25 provides a
single valve actuation parameter designed as the lift height. The
exhaust valve actuation curve for the normal mode has a single
lift. The second cam track 28 of the exhaust cams 24, 25 provides
two valve actuation parameters 29, 30 designed as the lift height.
The valve actuation parameters 29, 30 of the second cam track 28 of
the exhaust cams 24, 25, designed as the lift height, are different
from one another. The valve actuation parameter 29 of the second
cam track 28 of the exhaust cams 24, 25, designed as the lift
height, is larger than the valve actuation parameter 30 of the
second cam track 28 of the exhaust cams 24, 25, designed as the
lift height. The valve actuation parameter 30 of the second cam
track 28 of the exhaust cams 24, 25, designed as the lift height,
is provided for the internal exhaust gas recirculation, and opens
the corresponding exhaust valve during a downward movement of a
piston, the corresponding intake valve being largely closed due to
the intake valve actuation curve 37. The exhaust valve actuation
curve 41 for the exhaust gas recirculation mode has a double
lift.
[0030] The valve actuation parameters 29, 30 of the second cam
track 28 of the exhaust cams 24, 25, designed as the lift height,
both differ from the valve actuation parameter of the first cam
track 40 of the exhaust cams 24, 25, designed as the lift height.
The valve actuation parameters 29, 30 of the second cam track 28 of
the exhaust cams 24, 25, designed as the lift height, are both
smaller than the valve actuation parameter of the first cam track
40 of the exhaust cams 24, 25, designed as the lift height. The
lift of the exhaust valve actuation curve 41 for the exhaust gas
recirculation mode is smaller than the lift of the exhaust valve
actuation curve for the normal mode.
[0031] The second cam track 28 of the exhaust cams 24, 25 also
provides a valve actuation parameter designed as the opening
duration and which differs from a valve actuation parameter of the
first cam track 40 of the exhaust cams 24, 25, designed as the
opening duration. The valve actuation parameter of the second cam
track 28 of the exhaust cams 24, 25, designed as the opening
duration, is longer than the valve actuation parameter of the first
cam track 40 of the exhaust cams 24, 25, designed as the opening
duration. The valve actuation parameter of the second cam track 28
of the exhaust cams 24, 25, designed as the opening duration, sets
two exhaust valve opening phases 22, 23 of the exhaust valves,
which together are longer than a single exhaust valve opening phase
of the exhaust valves which is set by the valve actuation parameter
of the first cam track 40 of the exhaust cams 24, 25, designed as
the opening duration.
[0032] The valve actuation parameter of the first cam track 40 of
the exhaust cams 24, 25, designed as the lift height, is designed
as a maximum lift of the exhaust valve actuation curve for the
normal mode. The valve actuation parameters 29, 30 of the second
cam track 28 of the exhaust cams 24, 25, designed as the lift
height, are each designed as a maximum lift of the exhaust valve
actuation curve 41 for the exhaust gas recirculation mode.
[0033] The exhaust valve actuation curve 41 has a zero lift 45,
with respect to a crankshaft angle 44 in degrees, between the
maximum lifts of the exhaust valve actuation curve 41. The zero
lift 45 is situated with respect to the crankshaft angle 44 in
degrees in such a way that a collision between the piston of the
internal combustion engine and the corresponding exhaust valve is
prevented. The zero lift 45 is situated, with respect to the
crankshaft angle 44 in degrees, in the region of an ignition top
dead center. A lift of the piston is represented by a piston lift
curve 46. The smaller maximum lift of the exhaust valve actuation
curve 41 for the exhaust gas recirculation mode is situated with
respect to the crankshaft angle 44 in degrees, and within a working
cycle, between the larger maximum lift of the exhaust valve
actuation curve 41 for the exhaust gas recirculation mode and the
maximum lift of the intake valve actuation curve 37 for the exhaust
gas recirculation mode. Within the working cycle, the maximum lift
of the intake valve actuation curve 37 for the exhaust gas
recirculation mode is situated, with respect to the crankshaft
angle 44 in degrees, after the two maximum lifts of the exhaust
valve actuation curve 41 for the exhaust gas recirculation mode. In
principle, instead of a zero lift 45, the exhaust valve actuation
curve 41 may have a local minimum lift, with respect to the
crankshaft angle 44 in degrees, between the maximum lifts of the
exhaust valve actuation curve 41.
[0034] The exhaust valve actuating unit 10 has an exhaust cam
element 42 for accommodating the exhaust cams 24, 25. The exhaust
cams 24, 25 are each situated on the exhaust cam element 42 in a
rotationally and displaceably fixed manner. For accommodating the
exhaust cam element 42, the exhaust valve actuating unit 10 has an
exhaust cam base shaft 43, which is in drive connection with the
crankshaft of the internal combustion engine. The exhaust cam
element 42 is situated on the exhaust cam base shaft 43 so as to be
rotationally fixed but axially displaceable. The exhaust valve
actuating unit 10 is designed as an exhaust camshaft unit.
[0035] The intake valve actuation curve 37 for the exhaust gas
recirculation mode and the exhaust valve actuation curve 41 for the
exhaust gas recirculation mode differ from one another. The intake
valve actuation curve 37 for the exhaust gas recirculation mode has
a lift that differs from the lift of the exhaust valve actuation
curve 41 for the exhaust gas recirculation mode.
[0036] The valve actuation parameter 19 of the second cam track 18
of the intake cams 13, 14, designed as the lift height, differs
from both valve actuation parameters 29, 30 of the second cam track
28 of the exhaust cams 24, 25, designed as the lift height. The
valve actuation parameter 19 of the second cam track 18 of the
intake cams 13, 14, designed as the lift height, is smaller than
one of the two valve actuation parameters 29, 30 of the second cam
track 28 of the exhaust cams 24, 25, designed as the lift height.
The valve actuation parameter 19 of the second cam track 18 of the
intake cams 13, 14, designed as the lift height, is smaller than
the valve actuation parameter 29 of the second cam track 28 of the
exhaust cams 24, 25, designed as the lift height, and larger than
the valve actuation parameter 29 of the second cam track 28 of the
exhaust cams 24, 25, designed as the lift height.
[0037] The second cam track 18 of the intake cams 13, 14 sets the
intake valve opening phase 21 essentially outside the exhaust valve
opening phases 22, 23. The intake valve actuation curve 37 is
designed in such a way that the intake valve opening phase 21 is
set essentially outside the exhaust valve opening phases 22, 23.
The intake valves are thus largely closed during an actuation of
the exhaust valves. The intake valves are therefore largely closed
during a return of an exhaust gas recirculation quantity. An intake
valve opening point 47 is situated within the exhaust valve opening
phase 23. An intake valve closing point 48 is situated outside both
exhaust valve opening phases 22, 23. The corresponding intake
valves are opened within the intake valve opening phase 21, and the
corresponding exhaust valves are opened within the exhaust valve
opening phases 22, 23. The exhaust valve opening phase 23 is
provided for the internal exhaust gas recirculation, and sets the
exhaust gas recirculation quantity in the exhaust gas recirculation
mode. The exhaust valve opening phase 23 is designed as an exhaust
gas recirculation opening phase.
[0038] The intake valve actuation curve 37 for the exhaust gas
recirculation mode and the exhaust valve actuation curve 41 for the
exhaust gas recirculation mode have only a single overlap area 49
within a working cycle, and thus within two crankshaft revolutions.
Within a working cycle, the overlap area 49 is situated, with
respect to the crankshaft angle 44 in degrees, after the maximum
lifts of the exhaust valve actuation curve 41. Within a working
cycle, the overlap area is situated, with respect to the crankshaft
angle 44 in degrees, between the smaller maximum lift of the
exhaust valve actuation curve 41 and the maximum lift of the intake
valve actuation curve 37. Within a working cycle, the overlap area
49 is situated, with respect to the crankshaft angle 44 in degrees,
between the zero lift 45 and the intake valve opening point 47;
within a working cycle the zero lift 45 is situated, with respect
to the crankshaft angle 44 in degrees, before the intake valve
opening point 47.
[0039] The intake valve actuation curve 37, the exhaust valve
actuation curve 41, and the piston lift curve 46 are plotted in a
diagram illustrated in FIG. 2, the crankshaft angle 44 in degrees
being plotted on the x axis of the diagram, and the lift being
plotted on the y axis of the diagram. In principle, the internal
combustion engine valve train device may also have a different
number of intake cams, intake cam elements, exhaust cams, and/or
exhaust cam elements which appear to be meaningful to those skilled
in the art.
[0040] For setting the normal mode and the exhaust gas
recirculation mode, the operating mode switching unit 12 switches
between the different intake valve actuation curves of the intake
valve actuating unit 11 and the different exhaust valve actuation
curves of the exhaust valve actuating unit 10. The operating mode
switching unit 12 has a switch gate 31 for switching the intake
valve actuating unit 11, and a switch gate 32 for switching the
exhaust valve actuating unit 10. The switch gate 31 is situated on
the intake cam element 38 in a rotationally and displaceably fixed
manner, and the switch gate 32 is situated on the exhaust cam
element 42 in a rotationally and displaceably fixed manner. For
switching the normal mode and the exhaust gas recirculation mode,
the switch gate 31 converts a rotary movement 33 of the intake cam
element 38 into an axial movement 35 of the intake cam element 38
along the intake cam base shaft 39. For switching the normal mode
and the exhaust gas recirculation mode, the switch gate 32 converts
a rotary movement 34 of the exhaust cam element 42 into an axial
movement 36 of the exhaust cam element 42 along the exhaust cam
base shaft 43. The switch gates 31, 32 have a gate track 50, 51,
respectively. In principle, the switch gate 31 may be formed in one
piece with the intake cam element 38, as a result of which the
intake cam element 38 includes the gate track 50. Additionally or
alternatively, the switch gate 32 may be formed in one piece with
the exhaust cam element 42, as a result of which the exhaust cam
element 42 includes the gate track 51.
[0041] The operating mode switching unit 12 also has an actuating
unit 52 for switching the intake valve actuating unit 11, and an
actuating unit 53 for switching the exhaust valve actuating unit
10. The actuating units 52, 53 each have a switch pin, not
illustrated, which for switching extends and engages with the
corresponding gate track 50, 51, thus converting the corresponding
rotary movement 33, 34 into the corresponding axial movement 35,
36, and thus switching the normal mode or the exhaust gas
recirculation mode. The operating mode switching unit 12 is
designed as a valve lift switching unit.
[0042] For controlling or regulating the switching, the operating
mode switching unit 12 has a control and regulation unit, not
illustrated, which is in communicating connection with the
actuating units 52, 53. The control and regulation unit controls or
regulates the extension of the switch pins. For adjusting the
internal exhaust gas recirculation, the control and regulation unit
switches the exhaust valve actuating unit 10 and also the intake
valve actuating unit 11 into the exhaust gas recirculation mode.
For setting the normal mode, the control and regulation unit
switches the exhaust valve actuating unit 10 and also the intake
valve actuating unit 11 into the normal mode.
[0043] The foregoing disclosure has been set forth merely to
illustrate the invention and is not intended to be limiting. Since
modifications of the disclosed embodiments incorporating the spirit
and substance of the invention may occur to persons skilled in the
art, the invention should be construed to include everything within
the scope of the appended claims and equivalents thereof
LIST OF REFERENCE NUMERALS
[0044] 10 Exhaust valve actuating unit
[0045] 11 Intake valve actuating unit
[0046] 12 Operating mode switching unit
[0047] 13 Intake cam
[0048] 14 Intake cam
[0049] 17 Cam track
[0050] 18 Cam track
[0051] 19 Valve actuation parameter
[0052] 20 Valve actuation parameter
[0053] 21 Intake valve opening phase
[0054] 22 Exhaust valve opening phase
[0055] 23 Exhaust valve opening phase
[0056] 24 Exhaust cam
[0057] 25 Exhaust cam
[0058] 28 Cam track
[0059] 29 Valve actuation parameter
[0060] 30 Valve actuation parameter
[0061] 31 Switch gate
[0062] 32 Switch gate
[0063] 33 Rotary movement
[0064] 34 Rotary movement
[0065] 35 Axial movement
[0066] 36 Axial movement
[0067] 37 Intake valve actuation curve
[0068] 38 Intake cam element
[0069] 39 Intake cam base shaft
[0070] 40 Cam track
[0071] 41 Exhaust valve actuation curve
[0072] 42 Exhaust cam element
[0073] 43 Exhaust cam base shaft
[0074] 44 Crankshaft angle
[0075] 45 Zero lift
[0076] 46 Piston lift curve
[0077] 47 Intake valve opening point
[0078] 48 Intake valve closing point
[0079] 49 Overlap area
[0080] 50 Gate track
[0081] 51 Gate track
[0082] 52 Actuating unit
[0083] 53 Actuating unit
* * * * *