U.S. patent application number 12/968877 was filed with the patent office on 2011-12-29 for hydraulically activated exhaust flap.
This patent application is currently assigned to Benteler Automobiltechnik GmbH. Invention is credited to Sven Przybylski, Bjorn Richter.
Application Number | 20110314799 12/968877 |
Document ID | / |
Family ID | 43243795 |
Filed Date | 2011-12-29 |
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United States Patent
Application |
20110314799 |
Kind Code |
A1 |
Richter; Bjorn ; et
al. |
December 29, 2011 |
HYDRAULICALLY ACTIVATED EXHAUST FLAP
Abstract
A flap arrangement in an exhaust track of a motor vehicle
includes an exhaust flap and a slave cylinder for controlling an
operative position of the exhaust flap. The slave cylinder is
fluidly connected to a master cylinder by a hydraulic line
containing a hydraulic fluid in the form of liquid metal. The
movement of the master cylinder is thus transmitted via the liquid
metal to the slave cylinder. A mechanical coupling of the slave
cylinder with the exhaust flap moves the exhaust flap to a
respective operative position.
Inventors: |
Richter; Bjorn; (Paderborn,
DE) ; Przybylski; Sven; (Paderborn, DE) |
Assignee: |
Benteler Automobiltechnik
GmbH
Paderborn
DE
|
Family ID: |
43243795 |
Appl. No.: |
12/968877 |
Filed: |
December 15, 2010 |
Current U.S.
Class: |
60/324 |
Current CPC
Class: |
F01N 13/087
20130101 |
Class at
Publication: |
60/324 |
International
Class: |
F01N 13/00 20100101
F01N013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 15, 2009 |
DE |
102009058171.5-13 |
Claims
1. A flap arrangement in an exhaust track of a motor vehicle,
comprising: an exhaust flap; a slave cylinder for controlling an
operative position of the exhaust flap; and a master cylinder
fluidly connected to the slave cylinder by a hydraulic line
containing a hydraulic fluid in the form of liquid metal.
2. The flap arrangement of claim 1, wherein the exhaust flap is
mechanically coupled with the slave cylinder.
3. The flap arrangement of claim 1, further comprising an adjusting
actuator coupled with the master cylinder to control operation of
the master cylinder.
4. The flap arrangement of claim 3, wherein the adjusting actuator
is a linear actuator.
5. The flap arrangement of claim 3, wherein the adjusting actuator
is an electromagnetic stroke actuator.
6. The flap arrangement of claim 3, wherein the adjusting actuator
is a piezoelectric plug actuator.
7. The flap arrangement of claim 1, wherein the exhaust flap is
constructed in the form of a faceplate having a contour conforming
to an inner contour of the exhaust track.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the priority of German Patent
Application, Ser. No. 10 2009 058 171.5-13, filed Dec. 15, 2009,
pursuant to 35 U.S.C. 119(a)-(d), the content of which is
incorporated herein by reference in its entirety as if fully set
forth herein.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a flap arrangement in an
exhaust TRACK of a motor vehicle.
[0003] The following discussion of related art is provided to
assist the reader in understanding the advantages of the invention,
and is not to be construed as an admission that this related art is
prior art to this invention.
[0004] Exhaust systems having exhaust flaps can be used to clear a
bypass or to route air mass flows and/or exhaust-gas flows in a
desired manner. Exhaust flaps find application in heat management
for Diesel particle filters and exhaust gas recirculation systems
or to change sound and pollutant emissions or to improve
performance of internal combustion engines through control of the
exhaust back pressure.
[0005] Conventional exhaust flaps are almost always controlled by
vacuum cells. Vacuum cells have the drawback however that they
enable only an uncontrolled operation between the states "OPEN" and
"CLOSED. A continuous fine tuning of the angle in the opening
position of the exhaust flap cannot be realized.
[0006] Also known in the prior art are exhaust flaps which are
operated by electric adjusting actuators. While being able to
individually grade the opening position, adjusting actuators cannot
be used in areas of the exhaust bypass that are subject to high
exhaust temperature. For example, their use directly on an exhaust
manifold of an internal combustion engine is not possible.
[0007] Furthermore, the periphery of conventional exhaust flaps
requires a large installation space in immediate environment of the
bypass. However, the space is tight especially in the area of the
manifold of an internal combustion engine.
[0008] It would therefore be desirable and advantageous to provide
an improved flap arrangement which obviates prior art shortcomings
and which can be controlled in a precise and continuous manner
while still being compact and reliable in operation for application
over a broad thermal spectrum.
SUMMARY OF THE INVENTION
[0009] According to one aspect of the present invention, a flap
arrangement in an exhaust track of a motor vehicle includes an
exhaust flap, a slave cylinder for controlling an operative
position of the exhaust flap, and a master cylinder fluidly
connected to the slave cylinder by a hydraulic line containing a
hydraulic fluid in the form of liquid metal.
[0010] The present invention resolves prior art problems by
providing a hydraulically actuatable slave cylinder. The hydraulic
actuation of the exhaust flap via the slave cylinder allows
disposition of an infinitely variable exhaust flap at almost any
portion of the exhaust track in the vehicle. The exhaust flap can
be adjusted in the operative position via the slave cylinder in
such a manner to enable an infinitely variable control between
fully open and fully closed states. The flap arrangement is compact
and can be controlled substantially temperature-independent. The
temperature dependency is primarily impacted by the thermal
properties of the used hydraulic fluid. The operativeness of the
flap mechanism is ensured even when the exhaust temperatures at the
manifold reach up to 1000.degree. C. The provision of a hydraulic
line to connect the slave cylinder with the master cylinder
provides flexibility so that the slave and master cylinders can be
installed at almost any site in the motor vehicle. The presence of
a limited installation space for attachment of an exhaust flap is
of no concern.
[0011] Liquid metal as hydraulic fluid is able to transmit the
respective movement of the master cylinder onto the slave cylinder
so as to move the slave cylinder accordingly. When the master and
slave cylinders are constructed in the form of a classic cylinder
and piston arrangement of a standard hydraulic cylinder, the slave
cylinder is moved linearly when the hydraulic line is set under
pressure by the master cylinder.
[0012] Liquid metals have a particularly low melting point of below
-20.degree. C. As a result the spectrum for use of a flap
arrangement according to the invention is broad, even in
circumstances when the outside temperatures are low during cold
start performance. The contact zone between the slave cylinder and
the flap mechanism is oftentimes exposed to high temperatures of up
to 600.degree. C. as a result of heat conduction of heat contained
in the exhaust flow. Liquid metals have a boiling point which
exceeds 1000.degree. C. The thermal impact of the hydraulic fluid
by the exhaust heat is therefore of no concern. Thus, all
temperature ranges can be covered by the thermal properties of the
liquid metal, when used in liquid form in an internal combustion
engine. An example of an appropriate liquid metal is Galinstan.RTM.
having gallium, indium and stannum (tin) as main alloying
components. Currently preferred is a liquid metal of a composition
in weight-% of 65 to 70% gallium, 20 to 25% indium, 5 to 15%
stannum, and 0 to 2% bismuth and 0 to 5% antimony. The hydraulic
coupling has also the benefit that little or no maintenance is
required.
[0013] According to another advantageous feature of the present
invention, the exhaust flap can be mechanically coupled with the
slave cylinder. As a result, any movement by the slave cylinder can
be transmitted to the exhaust flap directly or via a connection
rod. The mechanical coupling of the exhaust flap with the slave
cylinder is temperature-independent and robust.
[0014] According to another advantageous feature of the present
invention, an adjusting actuator may be coupled with the master
cylinder to control operation of the master cylinder. Examples of
adjusting actuators include a linear actuator, an electromagnetic
stroke actuator, or a piezoelectric plug actuator. Further examples
include linear motors, gear motors, or other electric or electronic
adjusting actuators. The actuator may be controlled mechanically or
electrically controllable, wherein the control may be mechanical or
automatic. In order to be able to work also with smaller movement
paths, the provision of a hydraulic force-path transmission may be
suitable by narrowing a through opening. The adjusting actuator may
also be realized by a piezoelectric stack actuator, when suitably
configuring the mechanical or hydraulic transmission. The adjusting
actuator is exposed to little temperature stress as a result of its
installation at a distance to the exhaust track.
[0015] According to another advantageous feature of the present
invention, the exhaust flap may be constructed in the form of a
faceplate having a contour conforming to an inner contour of the
exhaust track. In this way, the faceplate covers the entire inner
transverse cross-sectional area of the exhaust track in the closed
position. Suitably, the faceplate may be arranged for rotation
about a rotation axis in the exhaust track. As a result, the
faceplate can be turned from a closed position in which the entire
inner transverse cross-sectional area of the exhaust track is
covered, to an open position so as to establish maximum passage of
the exhaust gas.
[0016] According to another advantageous feature of the present
invention, the exhaust flap may be constructed as a butterfly
exhaust flap. The butterfly exhaust flap may hereby rotate
central-symmetrical about a rotation axis in the middle of the
exhaust track. Another example of an exhaust flap within the scope
of the present invention is an eccentric rotatably arranged exhaust
flap. The rotation axis can be supported by ceramic bushings and
sealed to maintain a reliable operation under conditions of high
exhaust temperatures. The exhaust flap may also be implemented by a
gate. Control of valves in the exhaust track may also be
contemplated. For example, an exhaust gas recirculation (EGR) valve
may be controlled via a hydraulic line with a liquid metal.
[0017] According to another advantageous feature of the present
invention, a sensor may be provided to detect an angular position
of the slave cylinder in the operative position. Depending on the
desired flow rate, the exhaust flap assumes an operative position
through adjustment about its rotation axis about an angle. This
operative position is set by the slave cylinder on one hand, and
influenced by flow resistances on the other hand. In order to
precisely detect the operative position at all times, the operative
position is measured in a rotation angle. The measured angle is
then used to calculate the opened area in the exhaust track and to
determine the exhaust flow rate.
[0018] According to another advantageous feature of the present
invention, the sensor may include two differential potentiometers
working in opposite directions. As a result of this configuration,
the change of the specific value of resistance is not impacted by
the temperature in the exhaust track. A rise in the specific
resistance of one differential potentiometer is compensated by the
increasing specific resistance of the contrarotating differential
potentiometer. The sensor may also be implemented by a differential
capacitance meter. This is beneficial because the applied measuring
method is not subject to wear.
[0019] An exhaust flap arrangement according to the present
invention for use in a motor vehicle exhibits a long service life
because the actuator is exposed to little thermal stress, an angle
determination is easy to realize in view of the differential
potentiometers working in opposite directions, and the construction
is cost-effective and simple in view of the absence of separate
cooling systems.
BRIEF DESCRIPTION OF THE DRAWING
[0020] Other features and advantages of the present invention will
be more readily apparent upon reading the following description of
currently preferred exemplified embodiments of the invention with
reference to the accompanying drawing, in which:
[0021] FIG. 1 is a schematic illustration of a flap arrangement
according to the present invention; and
[0022] FIG. 2 is a schematic illustration of an exhaust flap of the
flap arrangement in an exhaust track.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0023] Throughout all the figures, same or corresponding elements
may generally be indicated by same reference numerals. These
depicted embodiments are to be understood as illustrative of the
invention and not as limiting in any way. It should also be
understood that the figures are not necessarily to scale and that
the embodiments are sometimes illustrated by graphic symbols,
phantom lines, diagrammatic representations and fragmentary views.
In certain instances, details which are not necessary for an
understanding of the present invention or which render other
details difficult to perceive may have been omitted.
[0024] Turning now to the drawing, and in particular to FIG. 1,
there is shown a schematic illustration of a flap arrangement
according to the present invention, generally designated by
reference numeral 1 and arranged at an exhaust track 2 of a motor
vehicle. The flap arrangement 1 has an exhaust flap 3 in the
exhaust track 2 and is controlled via a slave cylinder 4. The slave
cylinder 4 is connected with a master cylinder 5 via a hydraulic
line 6. The master cylinder 5 is coupled with an adjusting actuator
7. A movement of the adjusting actuator 7 is thus transmitted onto
the master cylinder 5 which in turn transmits its movement via the
hydraulic line 6 onto the slave cylinder 4. The exhaust flap 3
completely closes in its "closed" position the exhaust track 2 by
fully flatly bearing upon an inner contour 8 of the exhaust track
2. The exhaust flap 3 is mechanically coupled with the slave
cylinder 4 so that the movement of the slave cylinder 4 is
converted in a rotation of the exhaust flap 3 about a rotation axis
9 in the illustrated non-limiting embodiment. Rotating the exhaust
flap 3 results in an open position at an angle 10 so that exhaust A
can flow through the exhaust track 2.
[0025] FIG. 2 shows a simplified sectional view of the exhaust
track 2. In the illustrated viewing direction, the exhaust flap 3
is shown in a "closed" position to seal off the exhaust track 2
because the outer shape of the exhaust flap 3 conforms to the inner
contour 8 of the exhaust track 2. A movement of the slave cylinder
4 (not shown in FIG. 2), causes a rotation of the exhaust flap 3
about the rotation axis 9. The operative position is hereby at an
angle which can be detected by a sensor 11.
[0026] While the invention has been illustrated and described in
connection with currently preferred embodiments shown and described
in detail, it is not intended to be limited to the details shown
since various modifications and structural changes may be made
without departing in any way from the spirit and scope of the
present invention. The embodiments were chosen and described in
order to explain the principles of the invention and practical
application to thereby enable a person skilled in the art to best
utilize the invention and various embodiments with various
modifications as are suited to the particular use contemplated.
[0027] What is claimed as new and desired to be protected by
Letters Patent is set forth in the appended claims and includes
equivalents of the elements recited therein:
* * * * *