U.S. patent application number 14/816446 was filed with the patent office on 2016-02-11 for vibration dampening muffler and system.
The applicant listed for this patent is General Electric Company. Invention is credited to Somnath Barole, Pravin Kohad, Pranav Raina, Bhaskar Chandra Saha.
Application Number | 20160040566 14/816446 |
Document ID | / |
Family ID | 55267064 |
Filed Date | 2016-02-11 |
United States Patent
Application |
20160040566 |
Kind Code |
A1 |
Barole; Somnath ; et
al. |
February 11, 2016 |
VIBRATION DAMPENING MUFFLER AND SYSTEM
Abstract
Various methods and systems are provided for damping vibrations
at a muffler. In one example, a system comprises an exhaust
component, a muffler configured to receive exhaust gas from the
exhaust component, and a vibration isolation device coupled between
the exhaust component and the muffler, the vibration isolation
device comprising a vibration dampening element and an active
biasing element.
Inventors: |
Barole; Somnath; (Bangalore,
IN) ; Raina; Pranav; (Bangalore, IN) ; Saha;
Bhaskar Chandra; (Bangalore, IN) ; Kohad; Pravin;
(Bangalore, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
55267064 |
Appl. No.: |
14/816446 |
Filed: |
August 3, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62033200 |
Aug 5, 2014 |
|
|
|
Current U.S.
Class: |
181/207 |
Current CPC
Class: |
F01N 2590/08 20130101;
F01N 13/1816 20130101; F01N 1/00 20130101; F01N 13/1811
20130101 |
International
Class: |
F01N 1/20 20060101
F01N001/20 |
Claims
1. A system, comprising: an exhaust component; a muffler configured
to receive exhaust gas from the exhaust component; and a vibration
isolation device coupled between the exhaust component and the
muffler, the vibration isolation device comprising a vibration
dampening element and an active biasing element.
2. The system of claim 1, wherein the vibration dampening element
comprises a spring, and wherein active biasing element is coupled
to the spring.
3. The system of claim 1, wherein the active biasing element
comprises a bi-metallic structure.
4. The system of claim 1, wherein the active biasing element
comprises a one-way shape-memory alloy.
5. The system of claim 4, wherein the alloy comprises nickel and
titanium.
6. The system of claim 1, wherein the active biasing element is
responsive to a temperature of 20 degrees Celsius or greater to
return to a determined shape or configuration.
7. The system of claim 1, wherein the exhaust component is coupled
to a turbocharger.
8. The system of claim 7, wherein the vibration isolation device is
coupled between an outrigger plate of an exhaust outlet of a
turbine of the turbocharger and a base plate of an exhaust inlet of
the muffler.
9. The system of claim 8, wherein the vibration isolation device is
a first vibration isolation device, and further comprising a second
vibration isolation device that is coupled between the outrigger
plate and the base plate.
10. The system of claim 8, further comprising one or more of bellow
and liner plate coupled to the outrigger plate, the one or more of
the bellow and liner plate configured to seal an exhaust gas stream
between the turbine of the turbocharger and the muffler.
11. The system of claim 1, wherein the active biasing element is a
first active biasing element, and wherein the muffler comprises an
inner liner, an outer liner, and at least one additional active
biasing element coupled between the inner liner and the outer
liner.
12. A muffler, comprising: an outer liner; an inner liner
positioned within the outer liner and configured to receive exhaust
gas; and at least one active biasing element coupled between the
outer liner and the inner liner.
13. The muffler of claim 12, wherein the at least one active
biasing element is positioned along a longitudinal axis of the
muffler.
14. The muffler of claim 12, wherein the at least one active
biasing element comprises a brace.
15. The muffler of claim 12, wherein the active biasing element
clamps the inner and outer liners more tightly at exhaust gas
temperatures above a threshold temperature.
16. The muffler of claim 12, wherein the outer liner is coupled to
a base plate of the muffler at a first end and a top lid of the
muffler at a second end, and wherein the inner liner is coupled to
a stand-off of the base plate of the muffler at a first end and the
top lid at a second end.
17. The muffler of claim 16, wherein the base plate of the muffler
is coupled to a turbocharger, the exhaust gas received from the
turbocharger.
18. The muffler of claim 17, wherein the base plate of the muffler
is coupled to the turbocharger via one or more vibration isolation
devices, the one or more vibration isolation devices each
comprising a respective vibration dampening element and a
respective active biasing element.
19. A system, comprising: a turbocharger; a muffler configured to
receive exhaust gas from the turbocharger, the muffler comprising
an outer liner, an inner liner positioned within the outer liner,
and at least one first active biasing element coupled between the
outer liner and the inner liner; and a vibration isolation device
coupled between the turbocharger and the muffler, the vibration
isolation device comprising a vibration dampening element and a
second active biasing element.
20. The system of claim 19, wherein the second active biasing
element is responsive to a threshold temperature to return to a
determined shape or configuration, and further comprising a
controller configured to increase an exhaust gas temperature to the
threshold temperature or greater in response to a vibration level
of the turbocharger exceeding a vibration level threshold.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Patent Application
No. 62/033,200, entitled MUFFLER VIBRATION DAMPENING, filed Aug. 5,
2014, which is hereby incorporated in its entirety herein by
reference for all purposes.
FIELD
[0002] Embodiments of the subject matter disclosed herein relate to
a system for an engine exhaust.
BACKGROUND
[0003] When exhaust gas is expelled out of an engine, the gas
produces noise that may be undesirable to an operator or bystander,
and thus exhaust systems typically include a muffler to attenuate
the noise produced by the exhaust gas. Mufflers may be exposed to
various excitation forces, including engine excitations, high
frequency turbo excitations, gas pressure, thermal loads, etc. Due
to these excitation forces, mufflers may become degraded, for
example, they may experience weld failures. Typical mechanisms for
damping vibrations, such as rubber pads fastened to the muffler
and/or exhaust component to which the muffler is coupled, are prone
to degradation from exposure to high temperature exhaust gases.
BRIEF DESCRIPTION
[0004] In one embodiment, a system comprises an exhaust component,
a muffler configured to receive exhaust gas from the exhaust
component, and a vibration isolation device coupled between the
exhaust component and the muffler. The vibration isolation device
includes a vibration dampening element and an active biasing
element.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The invention will be better understood from reading the
following description of non-limiting embodiments, with reference
to the attached drawings, wherein below:
[0006] FIG. 1 shows a schematic diagram of a vehicle with a
turbocharger according to an embodiment of the disclosure.
[0007] FIG. 2 shows a front view of a muffler coupled to a
turbocharger.
[0008] FIG. 3 shows a cross-sectional view of the
muffler-turbocharger system of FIG. 2.
DETAILED DESCRIPTION
[0009] Embodiments of the subject matter disclosed herein relate to
a system including a muffler coupled to an exhaust component and a
vibration isolation device coupled between the muffler and the
exhaust component. The vibration isolation device comprises a
vibration dampening element, such as a spring, and an active
biasing element, such as a shape-memory alloy wire. The system may
be installed in an exhaust system of an engine, and the exhaust
component and muffler may each receive a flow of exhaust gas from
the engine. In some examples, the exhaust component to which the
muffler is coupled may be a turbocharger turbine. In other
examples, the muffler may be coupled to an aftertreatment device or
directly to the engine. The muffler may include any number or
configuration of sound-absorbing, cancellation, or reflection
chambers.
[0010] The approach described herein may be employed in a variety
of engine types, and a variety of engine-driven systems selected
with reference to application specific criteria. Some of these
systems may be stationary, while others may be on semi-mobile or
mobile platforms. Semi-mobile platforms may be relocated between
operational periods, such as mounted on flatbed trailers. Mobile
platforms include self-propelled vehicles. Such vehicles can
include on-road transportation vehicles, as well as mining
equipment, marine vessels, rail vehicles, and other off-highway
vehicles (OHV). For clarity of illustration, a locomotive may be
used as an example of a mobile platform supporting a system
incorporating an embodiment of the invention.
[0011] Aspects of the invention are disclosed with reference to a
vehicle having an engine and exhaust system, such as the vehicle
illustrated in FIG. 1. The exhaust system may include a
turbocharger having a turbine to receive exhaust gas from the
engine and pass the exhaust gas to a muffler. The turbine may be
coupled to the muffler via a vibration isolation device that
includes at least vibration dampening element surrounding an active
biasing element, as illustrated in FIGS. 2-3. The muffler may
include an outer liner surrounding an inner liner, and may further
include one or more active biasing elements coupled between the
inner and outer liners, as illustrated in FIG. 3.
[0012] Before further discussion of the vibration isolation
embodiments, a positioning of a turbocharger in an engine system is
shown. FIG. 1 shows a block diagram of an embodiment of a vehicle
system 100 (e.g., a locomotive system), herein depicted as vehicle
106. The illustrated vehicle is a rail vehicle configured to run on
a rail 110 via a plurality of wheels 112. As depicted, the vehicle
includes an engine system with an engine 104.
[0013] The engine receives intake air for combustion from an intake
passage 114. The intake may be any suitable conduit or conduits
through which gases flow to enter the engine. For example, the
intake may include an intake manifold 115, the intake passage, and
the like. The intake passage receives ambient air from an air
filter (not shown) that filters air from outside of the engine.
Exhaust gas resulting from combustion in the engine is supplied to
an exhaust, such as exhaust passage 116. The exhaust, or exhaust
passage, may be any suitable conduit through which gases flow from
the engine. For example, the exhaust may include an exhaust
manifold 117, the exhaust passage, and the like. Exhaust gas flows
through the exhaust passage and out of the engine system. In one
example, the engine is a diesel engine that combusts air and diesel
fuel through compression ignition. In other non-limiting
embodiments, the engine may combust fuel including gasoline,
kerosene, biodiesel, or other petroleum distillates of similar
density through compression ignition (and/or spark ignition). In
still further examples, the engine may be a dual or multi-fuel
engine configured to combust more than one fuel, such as diesel and
natural gas.
[0014] In one embodiment, the engine is a Vee engine (e.g.,
V-engine) having a first bank of cylinders and a second bank of
cylinders. In one example, the engine is a V-12 engine having
twelve cylinders. In other examples, the engine may be a V-6, V-8,
V-10, or V-16 or any suitable V-engine configuration. In another
embodiment, the engine is an in-line engine including a plurality
of cylinders. The engine includes an engine block and an engine
head. The engine head includes a plurality of cylinder heads, each
cylinder head including a respective cylinder. Each cylinder head
includes a valve cover. Additionally, each cylinder head includes a
fuel injector. Each fuel injector passes through a respective valve
cover and connects to a high pressure fuel line. The high pressure
fuel line runs along a length of the engine. Each cylinder head is
further coupled to the exhaust manifold. As such, exhaust gases
produced during combustion exit the cylinder heads through the
exhaust manifold and then flow to the exhaust passage. The exhaust
passage contains additional engine system components, including a
turbine of a turbocharger 120 and a muffler 210, described further
below.
[0015] The turbocharger is arranged between the intake passage and
the exhaust passage. The turbocharger increases air charge of
ambient air drawn into the intake passage in order to provide
greater charge density during combustion to increase power output
and/or engine-operating efficiency. The turbocharger may include a
compressor (not shown in FIG. 1) which is at least partially driven
by a turbine (not shown in FIG. 1). While in this case a single
turbocharger is included, the system may include multiple turbine
and/or compressor stages. As shown in FIG. 1, the turbocharger is
coupled to the engine and mounted on an integrated front end 102
(e.g., shelf) of the engine. The integrated front end provides
various mounting bosses for support structures supporting various
components of the engine, including the turbocharger. Due to the
mounting of the turbocharger on the integrated front end of the
engine, the turbocharger may experience a larger amount of
vibrations than traditional turbocharger mounting configurations
(e.g., where the turbocharger is bolted directly to the
engine).
[0016] FIG. 1 shows a coordinate axis 122 including a vertical axis
124, a horizontal axis 126, and a lateral axis 128. The
turbocharger has a vertical exhaust outlet 130, the vertical
exhaust outlet positioned vertically (e.g., perpendicular) with
respect to a longitudinal axis 132 of the engine. The longitudinal
axis of the engine is aligned with the horizontal axis and the
vertical exhaust outlet is aligned with the vertical axis. As such,
a flow direction of exhaust through the vertical exhaust outlet is
perpendicular to a flow direction of exhaust through the exhaust
passage upstream of the turbocharger.
[0017] In some embodiments, the engine system may include an
exhaust gas treatment system coupled in the exhaust passage
upstream or downstream of the turbocharger. In one example
embodiment having a diesel engine, the exhaust gas treatment system
may include a diesel oxidation catalyst (DOC) and a diesel
particulate filter (DPF). In other embodiments, the exhaust gas
treatment system may additionally or alternatively include one or
more emission control devices. Such emission control devices may
include a selective catalytic reduction (SCR) catalyst, three-way
catalyst, NO.sub.x trap, as well as filters or other systems and
devices.
[0018] A controller 148 may be employed to control various
components related to the vehicle system. In one example, the
controller includes a computer control system. The controller
further includes computer readable storage media (not shown)
including code for enabling on-board monitoring and control of rail
vehicle operation. The controller, while overseeing control and
management of the vehicle system, may receive signals from a
variety of sensors 150 to determine operating parameters and
operating conditions, and correspondingly adjust various engine
actuators 152 to control operation of the vehicle. For example, the
controller may receive signals from various engine sensors
including, but not limited to, engine speed, engine load, boost
pressure, exhaust pressure, ambient pressure, exhaust temperature,
and the like. Correspondingly, the controller may control aspects
and operations of the vehicle system by sending commands to various
components such as traction motors, alternator, cylinder valves,
throttle, and the like.
[0019] FIG. 2 illustrates an example muffler system 200 including a
muffler 210 coupled to a turbocharger (such as turbocharger 120 of
FIG. 1) via a vibration isolation device. The muffler system may be
included as part of vehicle system 100 of FIG. 1. The turbocharger
includes a turbine 202 and compressor 204. Exhaust gas from an
engine, such as engine 104 of FIG. 1, enters the turbine via
turbine inlet 206, impinges on the blades of a turbine rotor (not
shown), causing the rotor to spin a shaft coupled to a rotor of the
compressor, and exits the turbine via a turbine outlet 208.
[0020] The turbine outlet is fluidically coupled to muffler inlet
212. Exhaust gas from the turbine is passed to the muffler via the
muffler inlet. The exhaust gas may pass through one or more
chambers or other sound-reducing structures within the muffler
before exiting the muffler via muffler outlet 214. The muffler
outlet may be fluidically coupled to an exhaust passage, such as
exhaust passage 116, in some examples.
[0021] The close coupling of the muffler and turbocharger may place
a large amount of excitation forces on the muffler, as the thermal
load and vibrations of the turbocharger are transmitted to the
muffler. Further, the turbocharger mounting configuration, where
the turbocharger is supported by the integrated front end of the
engine, causes additional vibrations to be passed to the muffler.
The excitation forces may result in degradation to the muffler,
particularly at welded joints of the muffler. To address this,
vibration isolators may be coupled between the turbine and the
muffler. The types of vibration isolators that may be used,
however, are limited due to the high heat environment and limited
packaging space available. While a spring may be present to absorb
vibrations and/or isolate the muffler from turbocharger vibrations,
the spring's ability to isolate vibrations may be limited to a
certain extent since theoretically a spring mass system will come
to rest at an infinite time once the spring is displaced from its
original position.
[0022] According to embodiments disclosed herein and elaborated
with respect to FIGS. 2-3, a vibration isolation device 218
including a vibration dampening element and an active biasing
element may be coupled between the turbocharger and muffler. When a
load is applied on the active biasing element, it undergoes
deformation and when the active biasing element is heated to a
certain temperature, it regains its original predetermined shape.
Thus, when the active biasing element is simultaneously heated at
certain temperature and a load is placed on it, it will try to
regain its original shape, producing internal forces which are in
opposite direction of the applied force. This property may be used
for vibration damping when used in combination with the vibration
dampening element (e.g., a spring). Use of vibration dampening
element along with an active biasing element can absorb and reduce
the high frequency turbo excitations encountered by the muffler,
which leads to improved life of weld joints and improved
reliability for the muffler.
[0023] The vibration isolation device may be coupled between an
outrigger plate of the turbocharger (illustrated as outrigger plate
222 of FIG. 3) and a base plate 216 of the muffler. Further, a
bellow 220 and/or liner plate 221 (illustrated in FIG. 3) may be
present to seal the fluid coupling between the turbine outlet and
muffler inlet, in order to prevent leaks of exhaust gas, provide
thermal insulation, direct the exhaust gas in a desired flow path,
and/or additional functions. The bellow may be welded or otherwise
coupled to the outrigger plate and muffler base plate, while the
liner plate may be welded or otherwise coupled to the outrigger
plate The turbine outlet, outrigger plate, and bellow may
collectively form the vertical exhaust outlet 130 illustrated in
FIG. 1. While two vibration isolation devices are illustrated in
FIG. 2, it is to be understood that virtually any number of
vibration isolation devices may be present in the muffler
system.
[0024] FIG. 3 is a cross-sectional view 300 of the muffler system
200 of FIG. 2, including a more detailed view of the vibration
isolation device. As shown in FIG. 3, the vibration isolation
device includes a vibration dampening element 224 and an active
biasing element 226. The vibration dampening element may be a
spring. The spring may be a suitable spring, such as a leaf or coil
spring, and/or the spring may comprise a helical, coiled material,
such as spring steel, wound around the active biasing element and
having a suitable spring force. In one example, the spring force
may be selected based on kx for the spring element, where k is
stiffness of the spring; x is spring deflection and .sigma.A for
the active biasing element, assuming a linear stress-strain
assumption in the operating temperature range where .sigma. is
stress on the active biasing element and A is the area of cross
section of the active biasing element. The active biasing may have
a shear modulus in a range of 70-90 GPa and may be comprised of a
wire having a diameter in a range of 8-15 mm. The wire may be wound
into a coil having a suitable number of turns, such as in a range
of 8-12 turns, resulting in a pitch in a range of 4-8 mm, for
example. The active biasing element may have an overall diameter
(e.g., coil diameter) in a range of 20-40 mm.
[0025] Thus, the active biasing element may be surrounded by the
vibration dampening element and may be parallel to and aligned with
a central axis 228 of the vibration dampening element. The central
axis of the vibration dampening element may be aligned with the
vertical axis of the coordinate system of FIG. 1. The vibration
dampening element and active biasing element may each have a first
end mechanically coupled to the outrigger plate of the turbocharger
or other suitable turbine outlet structure. The vibration dampening
element and active biasing element may each have a second, opposite
end mechanically coupled to the base plate or other suitable
structure of the muffler.
[0026] In one example, the active biasing element may be comprised
of a suitable material, such as a bi-metallic structure or an alloy
of nickel and titanium, an alloy of copper, aluminum, and nickel,
iron-based alloys, or copper-based alloys. Each of the above-listed
materials may have differing tensile strengths, heat tolerance,
shape-regaining capabilities, etc., and as such a desired material
may be selected based on application-specific parameters (e.g., how
much force the material may be exposed to, the temperature of the
environment in which the material is placed, etc.).
[0027] The active biasing element may be a one-way shape-memory
alloy that "remembers" a shape such that following a deformation
resulting from an applied force, the material can return to its
original shape when heated above a transition temperature. In
another example, the active biasing element may be a two-way
shape-memory alloy that "remembers" two shapes, one at low
temperatures, and one at temperatures above a transition
temperature. The two-way shape memory alloy may be pre-stressed in
some examples, such that the material assumes a desired shape
capable of absorbing applied forces upon deformation, rather
deforming to an undesired shape following application of force.
[0028] As described above, the active biasing element may be tuned
to return to its original shape at a desired temperature, following
deformation due to an applied force. The active biasing element may
be heated from exhaust gas passing through the turbocharger and
muffler. The active biasing element may be tuned to a suitable
temperature, such as 100.degree. C., 50.degree. C., 30.degree. C.,
or other suitable temperature, depending on the vibration isolation
demands of the system. In one example, the active biasing element
may be tuned to regain its original shape following deformation
when the active biasing element is heated to room temperature
(e.g., 20.degree. C.). In another example, the active biasing
element may have an activation (e.g., transition) temperature in a
range of 9-49.degree. C. The tuned temperature of the active
biasing element is dependent on the relative ratio of the metals
comprising the alloy of the wire. In one example, the active
biasing element may include a ratio of nickel to titanium of 50%
nickel to 50% titanium, although other ratios are possible. The
active biasing element may have a shear modulus in a range of 60-75
GPa when in a hyper-elastic stage. The active biasing element may
comprise a wire, and the wire may have a suitable thickness, such
as less than 10 mm. In one example, the diameter may be in the
range of 2-6 mm. The thickness of the wire may vary per weight of
the muffler, magnitude of excitations and amount of damping to be
provided, for example. The wire may have a suitable length, such as
in a range of 65-80 mm. The vibration isolation device may be
comprised of more than one vibration dampening element-active
biasing element pair. For example, the vibration isolation device
may be comprised of 10-20 vibration dampening element-active
biasing element pairs, which may be spaced together in one or more
clusters or may be evenly dispersed along the interface between the
turbocharger and muffler.
[0029] In one example, a vibration isolation device comprises a
vibration dampening element wound around an active biasing element.
The vibration dampening element may comprise a steel spring having
a shear modulus of 80 GPa. A diameter of the wire comprising the
spring may be 12 mm. The spring may be comprised of ten turns and
have a coil diameter of 30 mm, with a pitch of the spring being 6
mm. The active biasing element may be comprised of a wire having a
composition of 50% nickel and 50% titanium with a diameter of 4 mm
and length of 72 mm. The modulus of the wire in a hyper-elastic
stage may be 67 GPa. The vibration isolation device may be
comprised 16 vibration dampening element-active biasing element
pairs. Together, these parameters may provide for a vibration
isolation device that attenuates transfer of vibrations from the
turbocharger to the muffler when the muffler and turbocharger are
sized and positioned for use in a large engine system, such as that
of a locomotive.
[0030] The muffler may include an outer liner 232 surrounding an
inner liner 230, with an air gap between the outer liner and the
inner liner. The outer liner may be coupled to the base plate of
the muffler. The inner liner may also be coupled to the base plate
of the muffler, via one or more standoffs in some examples. Both
the outer liner and inner liner may be coupled to a top lid 234 of
the muffler.
[0031] The inner and outer liner may each undergo deformation
during operation of the engine and turbocharger, producing stress
in weld areas, which leads to weld joint failures in weld joints
between outer liner-base plate, inner liner-standoff bottom plate,
outer liner-top lid, etc. As illustrated in FIG. 3, the inner liner
and outer liner may be coupled via one or more active biasing
elements 236. The active biasing elements coupled between the inner
and outer liner may be positioned at high deflection points, such
as at the center of the muffler, e.g., aligned along or arranged
across longitudinal axis 238 of the muffler. The longitudinal axis
of the muffler may be aligned with the horizontal axis of the
coordinate system illustrated in FIG. 1. Such an arrangement
reduces relative movement of the inner and outer liners and makes
the muffler stiffer. Other mechanisms for strengthening the
muffler, such as ribs between the inner and outer liner, may
increase muffler weight. Active biasing elements, on the other
hand, are very light in weight and thus adding active biasing
elements for increasing the muffler stiffness does not increase the
weight of the muffler. Here, the active biasing elements may be in
hyper-elastic form and may be heated by exhaust gases. When the
inner and outer liner start to move away from each other, the
forces will deform the active biasing elements. Since the active
biasing elements are in hyper-elastic form, each element will try
to regain its initial unreformed shape, producing forces in the
opposite direction, minimizing deformations and producing damping.
This described arrangement makes the muffler stiffer and may reduce
weld failures in the muffler.
[0032] The composition of the active biasing elements coupling the
inner and outer liner may be similar to the composition of the
active biasing element of the vibration isolation device coupling
the muffler to the turbocharger, as described above. In other
examples, the active biasing elements between the inner and outer
liner may have a different composition and/or thickness.
[0033] Thus, as explained above, an active biasing element may be
present to dampen vibrations passed from one engine component to
another, such as from a turbocharger to a muffler. The active
biasing element may be tuned to regain an original shape following
a deformation and exposure to temperature above a transition
temperature. As such, at relatively low temperatures (e.g.,
temperatures below the transition temperature), the active biasing
element may couple the two engine components together according to
a first shape, and then if a force is applied to the active biasing
element (e.g., if the turbocharger vibrates or otherwise moves),
the active biasing element may couple the two engine components
together in a second, deformed shape. For example, the active
biasing element may bend, contract, or otherwise deform, in a
direction of the applied force. Then, once the temperature of the
active biasing element reaches the transition temperature, the
active biasing element may couple the two engine components
together in the original shape. In this way, when the active
biasing element temperature is relatively low (due to low exhaust
temperature, or due to the engine not being in operation, for
example), the active biasing element may allow more vibrations to
be passed from one engine component to another (e.g., more
vibrations may be passed from the turbocharger to the muffler).
When the active biasing element temperature is relatively high (due
to higher exhaust temperature resulting from engine operation,
engine operation at an increased load and/or engine speed, etc.),
fewer vibrations may be passed from the one engine component to
another. The transition temperature may be a function of the
relative proportions of the various materials comprising the active
biasing element.
[0034] In another example, the active biasing element may be
configured such that when the temperature of the active biasing
element is relatively high (e.g., above the transition
temperature), more vibrations are passed from one component to
another, and when the temperature of the active biasing element is
relatively low, fewer vibrations are passed from one component to
another. In a further example, if the temperature of the active
biasing element is higher than a second threshold temperature,
greater than the transition temperature, the elasticity of the
active biasing element may be reduced or completely eliminated, so
that the active biasing element acts as more of a rigid brace
coupling the two engine components. Additionally, in some examples,
a seal or other coupling mechanism may become active during certain
conditions, in order to avoid damage to the engine components
(e.g., muffler) when the active biasing element experiences
slack.
[0035] As explained above, the shape regaining capabilities of the
active biasing element is dependent on the temperature of the
active biasing element. When the active biasing element couples two
engine exhaust components together, such as when the active biasing
element is coupled between the turbocharger and muffler, the shape
memory functionality of the active biasing element depends on
engine temperature. Thus, in some examples, a controller (such as
controller 148 of FIG. 1) may be configured to respond to vibration
levels of the engine and/or turbocharger, and adjust exhaust
temperature accordingly, to ensure the active biasing element is
capable of dampening vibrations. This may include purposely
increasing exhaust temperature, by adjusting fuel injection
parameters, EGR rate, engine load (by adjusting a notch throttle
setting, for example), engine speed, or other parameters.
[0036] While the above-described active biasing element and
vibration isolation device is described with respect to dampening
vibrations passed from a turbocharger to a muffler, other
configurations are possible. For example, the vibration isolation
device described herein may be coupled between the turbine housing
and compressor housing of the turbocharger, coupled between the
turbocharger and the engine and/or platform on which the
turbocharger is mounted, coupled at a pipe or conduit joint, or
other location subject to vibration.
[0037] An embodiment relates to a system comprising an exhaust
component, a muffler configured to receive exhaust gas from the
exhaust component, and a vibration isolation device coupled between
the exhaust component and the muffler, the vibration isolation
device comprising a vibration dampening element and an active
biasing element. In an example, the vibration dampening element
comprises a spring, and the active biasing element is positioned
within the spring, e.g., along a central axis of the spring.
[0038] The active biasing element may be comprised of a one-way
shape-memory alloy. The alloy may be comprised of nickel and
titanium in one example, or may be a bi-metallic structure in
another example. The active biasing element may be tuned to regain
its original structure at a temperature of 20.degree. C. or
greater.
[0039] In one example, the exhaust component comprises a
turbocharger. In other examples, the exhaust component may include
an engine, an aftertreatment device, or other suitable component
configured to expel exhaust gas. The vibration isolation device may
be coupled between an outrigger plate of an exhaust outlet of a
turbine of the turbocharger and a base plate of an exhaust inlet of
the muffler. The vibration isolation device may be a first
vibration isolation device, and the system may further comprise a
second vibration isolation device also coupled between the
outrigger plate and the base plate. The one or more vibration
isolation devices may create a gap between the outrigger plate and
the base plate. To seal the gap and prevent leakage of exhaust gas,
the system may further comprise one or more of a bellow and liner
plate coupled to the outrigger plate, the one or more of the bellow
and liner plate configured to seal an exhaust gas stream between
the turbine of the turbocharger and the muffler.
[0040] In an example, the active biasing element is a first active
biasing element. The muffler may comprise an inner liner, an outer
liner, and at least one additional active biasing element coupled
between the inner liner and the outer liner.
[0041] Another embodiment relates to a muffler. The muffler
comprises an outer liner, an inner liner positioned within the
outer liner and configured to receive exhaust gas, and at least one
active biasing element coupled between the outer liner and the
inner liner.
[0042] The at least one active biasing element may be positioned
along a longitudinal axis of the muffler. The at least one
shape-memory alloy wire may comprise 50% nickel and 50%
titanium.
[0043] The outer liner may be coupled to a base plate of the
muffler at a first end and a top lid of the muffler at a second
end. The inner liner may be coupled to a stand-off of the base
plate of the muffler at a first end and the top lid at a second
end. The active biasing element may act as a brace, and the active
biasing element may clamp the inner and outer liners more tightly
at exhaust gas temperatures above a threshold temperature relative
to how tightly the active biasing element may clamp the inner and
outer liners at exhaust gas temperatures below the threshold.
[0044] In an example, the base plate of the muffler is coupled to a
turbocharger, and the exhaust gas is received from the
turbocharger. The base plate of the muffler may be coupled to the
turbocharger via one or more vibration isolation devices, the one
or more vibration isolation devices each comprising a respective
vibration dampening element and a respective active biasing
element.
[0045] In an embodiment, a system comprises a turbocharger, a
muffler configured to receive exhaust gas from the turbocharger,
and a vibration isolation device coupled between the turbocharger
and the muffler. The muffler comprises an outer liner, an inner
liner positioned within the outer liner, and at least one first
active biasing element coupled between the outer liner and the
inner liner. The vibration isolation device comprises a vibration
dampening element and a second active biasing element. The second
active biasing element may be responsive to a threshold temperature
to return to a determined shape or configuration, and the system
may further comprise a controller configured to increase an exhaust
gas temperature to the threshold temperature or greater in response
to a vibration level of the turbocharger exceeding a vibration
level threshold.
[0046] The system further comprises an engine to pass exhaust gas
to the turbocharger, where the engine, turbocharger, and muffler
are installed in a vehicle.
[0047] As used herein, an element or step recited in the singular
and proceeded with the word "a" or "an" should be understood as not
excluding plural of said elements or steps, unless such exclusion
is explicitly stated. Furthermore, references to "one embodiment"
of the present invention are not intended to be interpreted as
excluding the existence of additional embodiments that also
incorporate the recited features. Moreover, unless explicitly
stated to the contrary, embodiments "comprising," "including," or
"having" an element or a plurality of elements having a particular
property may include additional such elements not having that
property. The terms "including" and "in which" are used as the
plain-language equivalents of the respective terms "comprising" and
"wherein." Moreover, the terms "first," "second," and "third," etc.
are used merely as labels, and are not intended to impose numerical
requirements or a particular positional order on their objects.
[0048] This written description uses examples to disclose the
invention, including the best mode, and also to enable a person of
ordinary skill in the relevant art to practice the invention,
including making and using any devices or systems and performing
any incorporated methods. The patentable scope of the invention is
defined by the claims, and may include other examples that occur to
those of ordinary skill in the art. Such other examples are
intended to be within the scope of the claims if they have
structural elements that do not differ from the literal language of
the claims, or if they include equivalent structural elements with
insubstantial differences from the literal language of the
claims.
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