U.S. patent application number 16/629073 was filed with the patent office on 2020-06-04 for acoustic volume in hot-end of exhaust systems.
The applicant listed for this patent is Faurecia Emissions Control Technologies, USA, LLC. Invention is credited to Frederic Blanco-Sotelo, James Egan, Marion Gonzalez, Jean Lagier, Djafar Larbi.
Application Number | 20200173320 16/629073 |
Document ID | / |
Family ID | 65808731 |
Filed Date | 2020-06-04 |
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United States Patent
Application |
20200173320 |
Kind Code |
A1 |
Lagier; Jean ; et
al. |
June 4, 2020 |
ACOUSTIC VOLUME IN HOT-END OF EXHAUST SYSTEMS
Abstract
A vehicle exhaust system includes a component housing defining
an internal cavity, a first exhaust gas treatment element
positioned within the internal cavity, a second exhaust gas
treatment element positioned within the internal cavity and axially
spaced from the first exhaust gas treatment element by a gap, and a
resonator volume in communication with the internal cavity.
Inventors: |
Lagier; Jean; (Arcey,
FR) ; Egan; James; (Indianapolis, IN) ; Larbi;
Djafar; (Muenchen, DE) ; Gonzalez; Marion;
(Montbeliard, FR) ; Blanco-Sotelo; Frederic;
(Boulot, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Faurecia Emissions Control Technologies, USA, LLC |
Columbus |
IN |
US |
|
|
Family ID: |
65808731 |
Appl. No.: |
16/629073 |
Filed: |
September 25, 2017 |
PCT Filed: |
September 25, 2017 |
PCT NO: |
PCT/US2017/053186 |
371 Date: |
January 7, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01N 2490/00 20130101;
F01N 13/1805 20130101; F01N 2230/02 20130101; F01N 3/0335 20130101;
F01N 13/0097 20140603; F01N 3/08 20130101; F01N 1/023 20130101;
F01N 1/02 20130101; G10K 11/172 20130101; F01N 3/2885 20130101;
F01N 1/089 20130101; F01N 2230/04 20130101 |
International
Class: |
F01N 1/02 20060101
F01N001/02; F01N 3/28 20060101 F01N003/28; F01N 3/033 20060101
F01N003/033; G10K 11/172 20060101 G10K011/172 |
Claims
1. A vehicle exhaust system comprising: a component housing
defining an internal cavity; a first exhaust gas treatment element
positioned within the internal cavity; a second exhaust gas
treatment element positioned within the internal cavity and axially
spaced from the first exhaust gas treatment element by a gap; and a
resonator volume in communication with the internal cavity.
2. The vehicle exhaust system according to claim 1 wherein the
resonator volume is formed between an outer surface of the
component housing and an inner surface of a resonator housing that
at least partially surrounds the component housing, and including
at least one resonator connection in communication with the
resonator volume, wherein the resonator connection is located at
the gap.
3. The vehicle exhaust system according to claim 1 wherein the
resonator volume is formed between an outer surface of the
component housing and an inner surface of a resonator housing that
at least partially surrounds the component housing, and including
an inlet cone positioned at one end of the component housing and an
outlet cone positioned at an opposite end of the component housing,
and including at least one resonator connection in communication
with the resonator volume, and wherein the at least one resonator
connection is located at one of the inlet and outlet cones.
4. The vehicle exhaust system according to claim 3 wherein the at
least one resonator connection comprises at least a first resonator
connection located at the gap and a second resonator connection
located at one of the inlet and outlet cones.
5. The vehicle exhaust system according to claim 1 wherein there is
no net flow out of the resonator volume.
6. The vehicle exhaust system according to claim 1 wherein the
resonator volume is formed between an outer surface of the
component housing and an inner surface of a resonator housing that
at least partially surrounds the component housing, and wherein the
resonator volume is concentric with the center axis such that the
resonator volume completely and entirely surrounds an outer
circumference of the first and second gas treatment elements.
7. The vehicle exhaust system according to claim 1 wherein the
resonator volume is formed between an outer surface of the
component housing and an inner surface of a resonator housing that
at least partially surrounds the component housing, and wherein the
resonator volume is offset relative to the component housing such
that the resonator volume only partially surrounds an outer
circumference of the first and second gas treatment elements.
8. The vehicle exhaust system according to claim 1 wherein the
resonator volume is enclosed within a resonator housing and
including at least one connection of the resonator housing to the
component housing.
9. The vehicle exhaust system according to claim 8 wherein the
component housing comprises a center housing portion that encloses
the first and second gas treatment elements, an inlet portion
positioned at one end of the center housing portion, and an outlet
portion positioned at an opposite end of the center housing
portion, and wherein the at least one connection comprises at least
one pipe that is connected to at least one of the center housing,
inlet, and outlet portions.
10. The vehicle exhaust system according to claim 10 wherein the
resonator housing is located externally of the component
housing.
11. The vehicle exhaust system according to claim 1 wherein the
resonator volume is enclosed within a resonator housing and
including at least one pipe that connects the resonator housing to
at least one of the component housing, an inlet pipe to the
component housing, and an outlet pipe from the component
housing.
12. The vehicle exhaust system according to claim 1 including a
plurality of resonator connections in communication with the
resonator volume.
13. The vehicle exhaust system according to claim 1 wherein the
resonator volume is in parallel with the first and second gas
treatment elements.
14. A vehicle exhaust system comprising: a first housing defining
an internal cavity; at least one exhaust gas treatment element
positioned within the internal cavity; a resonator volume spaced
radially outwardly of the at least one exhaust gas treatment
element; and a resonator connection to provide communication
between the resonator volume and the internal cavity.
15. The vehicle exhaust system according to claim 14 including a
second housing that defines the resonator volume, wherein the
resonator connection is either located internally within the second
housing or externally of the second housing.
16. A vehicle exhaust system comprising: a component housing
defining an internal cavity; an inlet coupled to an upstream end of
the component housing; an outlet coupled to a downstream end of the
component housing; a first exhaust gas treatment element positioned
within the internal cavity; a second exhaust gas treatment element
positioned within the internal cavity and separated from the first
exhaust gas treatment element by a gap; a resonator volume in
communication with the internal cavity; and a plurality of
resonator connections in communication with the resonator
volume.
17. The vehicle exhaust system according to claim 16 wherein the
second exhaust gas treatment element is axially spaced from the
first exhaust gas treatment element by the gap such that the first
and second exhaust gas treatment elements are coaxial, and wherein
the plurality of resonator connections comprises at least a first
resonator connection located at the gap and a second resonator
connection located at the inlet or outlet.
18. The vehicle exhaust system according to claim 17 wherein the
resonator volume is external to the component housing.
19. The vehicle exhaust system according to claim 16 including a
resonator housing that defines the resonator volume wherein the
resonator housing at least partially surrounds the component
housing.
20. The vehicle exhaust system according to claim 16 wherein the
second exhaust gas treatment element is in parallel with the first
exhaust gas treatment element such that the first and second
exhaust gas treatment elements are non-coaxial, and wherein the
plurality of resonator connections comprises at least a first
resonator connection located at the gap and a second resonator
connection located at the inlet or outlet.
Description
BACKGROUND OF THE INVENTION
[0001] An exhaust system conducts hot exhaust gases generated by an
engine through various exhaust components to reduce emissions,
improve fuel economy, and control noise. Short exhaust systems,
such as those encountered with hybrid vehicles or rear engine
vehicles for example, often have insufficient volume and/or length
to achieve a desired tailpipe noise level in combination with
acceptable back pressure levels. Further, as gasoline particulate
filter (GPF) technology emerges into the market, corresponding
increases in exhaust system back pressure will need to be offset in
order to avoid adverse effects on fuel economy or performance.
[0002] In addition to addressing issues raised by the introduction
of GPF technology, other emerging powertrain technologies are
requiring the industry to provide even more stringent noise
reduction. The frequencies that need to be attenuated are being
pushed to lower and lower frequencies not previously having to have
been addressed. One traditional solution to attenuate such
frequencies is to provide more internal volume; however, due to
tight packaging constraints, the area required for such volume is
not available. Another solution to attenuate these lower
frequencies is to use valves; however, valves drive a higher back
pressure at lower revolutions-per-minute, which is not desirable.
As such, there is a need for unique acoustic solutions that are
more efficient from a volume perspective and have less impact from
a back pressure aspect.
SUMMARY OF THE INVENTION
[0003] In one exemplary embodiment, a vehicle exhaust system
includes a component housing defining an internal cavity, a first
exhaust gas treatment element positioned within the internal
cavity, a second exhaust gas treatment element positioned within
the internal cavity and axially spaced from the first exhaust gas
treatment element by a gap, and a resonator volume in communication
with the internal cavity.
[0004] In a further embodiment of the above, the resonator volume
is formed between an outer surface of the component housing and an
inner surface of a resonator housing that at least partially
surrounds the component housing, and the system further includes at
least one resonator connection in communication with the resonator
volume, wherein the resonator connection is located at the gap.
[0005] In a further embodiment of any of the above, the resonator
volume is formed between an outer surface of the component housing
and an inner surface of a resonator housing that at least partially
surrounds the component housing, and the system further includes an
inlet cone positioned at one end of the component housing and an
outlet cone positioned at an opposite end of the component housing.
The system also includes at least one resonator connection in
communication with the resonator volume, and wherein the at least
one resonator connection is located at one of the inlet and outlet
cones.
[0006] In a further embodiment of any of the above, the resonator
volume is enclosed within a resonator housing and further including
at least one connection of the resonator housing to the component
housing.
[0007] In a further embodiment of any of the above, the resonator
housing is located externally of the component housing.
[0008] In a further embodiment of any of the above, the at least
one resonator comprises a plurality of resonator connections in
communication with a resonator volume.
[0009] In a further embodiment of any of the above, the resonator
volume is in parallel with the first and second gas treatment
elements.
[0010] In another exemplary embodiment, a vehicle exhaust system
includes a first housing defining an internal cavity, at least one
exhaust gas treatment element positioned within the internal
cavity, a resonator volume spaced radially outwardly of the at
least one exhaust gas treatment element, and a resonator connection
to provide communication between the resonator volume and the
internal cavity.
[0011] In a further embodiment of any of the above, a second
housing defines the resonator volume, and wherein the resonator
connection is either located internally within the second housing
or externally of the second housing.
[0012] In another exemplary embodiment, a vehicle exhaust system
includes a component housing defining an internal cavity, an inlet
coupled to an upstream end of the component housing, an outlet
coupled to a downstream end of the component housing, a first
exhaust gas treatment element positioned within the internal
cavity, and a second exhaust gas treatment element positioned
within the internal cavity and separated from the first exhaust gas
treatment element by a gap. The system further includes a resonator
volume in communication with the internal cavity and a plurality of
resonator connections in communication with the resonator
volume.
[0013] In a further embodiment of any of the above, the second
exhaust gas treatment element is axially spaced from the first
exhaust gas treatment element by the gap such that the first and
second exhaust gas treatment elements are coaxial, and wherein the
plurality of resonator connections comprises at least a first
resonator connection located at the gap and a second resonator
connection located at the inlet or outlet.
[0014] In a further embodiment of any of the above, the resonator
volume is external to the component housing.
[0015] In a further embodiment of any of the above, the second
exhaust gas treatment element is in parallel with the first exhaust
gas treatment element such that the first and second exhaust gas
treatment elements are non-coaxial, and wherein the plurality of
resonator connections comprises at least a first resonator
connection located at the gap and a second resonator connection
located at the inlet or outlet.
[0016] These and other features of this application will be best
understood from the following specification and drawings, the
following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 schematically illustrates a vehicle exhaust system
and shows standing pressure waves generated by the system.
[0018] FIG. 2 shows one example of a hot end component of the
system of FIG. 1 and which includes the subject invention.
[0019] FIG. 3 shows another example embodiment.
[0020] FIG. 4 shows another example embodiment.
[0021] FIG. 5A shows another example embodiment.
[0022] FIG. 5B shows another example embodiment.
[0023] FIG. 5C shows another example embodiment.
[0024] FIG. 6A shows another example embodiment.
[0025] FIG. 6B shows another example embodiment.
[0026] FIG. 6C shows another example embodiment.
[0027] FIG. 7 shows another example embodiment.
DETAILED DESCRIPTION
[0028] FIG. 1 shows a schematic representation of a vehicle exhaust
system 10 as a long pipe that conducts hot exhaust gases generated
by an engine 12 through various exhaust components to reduce
emission and control noise as known. The various exhaust components
can include one or more of the following: pipes, filters, valves,
catalysts, mufflers etc. The exhaust system 10 includes a hot end
14 that is located immediately downstream of the engine 12 and a
cold end 16 that is downstream of the hot end 14. The long pipe is
considered closed at an engine end 18 and open at an opposite end
20 where, after passing though the various exhaust components, the
engine exhaust gas exits the exhaust system 10 to atmosphere.
[0029] Exhaust components at the hot end 14 can include, for
example, exhaust gas treatment elements such as a diesel oxidation
catalyst (DOC), a diesel particulate filter (DPF), a gasoline
particulate filter (GPF), and a selective catalytic reduction (SCR)
catalyst that are used to remove contaminants from the exhaust gas
as known. Exhaust gases pass through these components and enter the
cold end 16 where the exhaust gas exits the system 10 via a
tailpipe. The described exhaust components can be mounted in
various different configurations and combinations dependent upon
vehicle application and available packaging space.
[0030] As discussed above, FIG. 1 shows the exhaust system
schematically illustrated as a long pipe that is closed at the
engine end 18 and open at the opposite end 20 to atmosphere.
Acoustic waves will travel from their source, which is the engine
12, down the pipe and then the exit to atmosphere. When the
acoustic wave encounters a boundary of some form, e.g. an impedance
change, then some fraction of the wave will be reflected back the
way it came and the remaining fraction will continue. In the case
of a closed-open pipe such as shown in FIG. 1, this reflection
occurs at the exit of the pipe. The reflected wave interferes with
the incident wave and at certain frequencies, which are a function
of the length of the pipe, constructively interfere to increase the
level of the wave and also to make the wave appear stationary. Such
waves are called standing waves and in the case of a closed-open
pipe the frequencies of such waves may be calculated with the
equation below.
Fn=(nc)/(4L) where:
[0031] fn=resonant frequency of standing wave n (Hz)
[0032] n=ordinal number of standing wave
[0033] c=speed of sound (m/s)
[0034] L=length of closed-open pipe (m)
[0035] The chart of FIG. 1 shows the first three standing pressure
waves for a closed-open pipe of 4 meters in length. In this
example, the resonances occur at 22, 65 and 108 Hz. As shown, for
each standing wave the pressure is a maximum (anti-node) at the
closed engine end 18 and a minimum (node) at the open end 20 to
atmosphere. The ideal place for a Helmholtz resonator is at a
pressure anti-node. As such, the best position for a resonator is
at the engine outlet; however, Helmholtz resonators are not
traditionally used in the hot end 14 of exhaust systems 10. The
subject invention provides a Helmholtz resonator in the hot end 14
to provide improved acoustic benefits over the same resonator as
placed in the cold end 16 as the subject resonator is closer to the
anti-node for all system acoustic resonances.
[0036] It has been shown through testing and simulations that a
Helmholtz Resonator, such as an acoustic volume of the order of 2
to 4 L in communication with the exhaust flow via a neck pipe for
example, that is positioned in the hot end 14 between a turbo
outlet and a converter, or between converter after-treatment
elements, provides an acoustic benefit about twice that of a
similar amount of volume applied in the cold end 16 (downstream of
the after-treatment) with no impact on back pressure. From a
tailpipe noise perspective, positioning the Helmholtz resonator as
close as possible to the engine 12 provides the best acoustic
performance
[0037] The subject invention proposes packaging one or more
Helmholtz Resonators at one of three locations in the hot end 14 of
the system 10. For example, the resonator(s) could be located after
the manifold or turbo outlet but before the converters, between the
converters; and/or after the converters. Various example
configurations are discussed below and shown in the accompanying
figures.
[0038] FIG. 2 shows one example of a hot end component 30 that is
situated downstream of the exhaust manifold and turbocharger. The
hot end component 30 includes a component housing 32 that defines
an internal cavity 34. A first exhaust gas treatment element 36 is
positioned within the internal cavity 34 and a second exhaust gas
treatment element 38 is positioned within the internal cavity 34
downstream and axially spaced from the first exhaust gas treatment
element 36 by a gap 40. A resonator volume 42 enclosed within a
resonator housing 43 is in communication with the internal cavity
34. The resonator housing 43 at least partially surrounds the
component housing 32.
[0039] An inlet cone 44 directs flow into the first exhaust gas
treatment element 36. The inlet cone 44 receives hot engine exhaust
gases from an inlet pipe 46. An outlet cone 48 directs treated
exhaust gas flow exiting the second exhaust gas treatment element
38 into an outlet pipe 50. In this example, the component housing
32 defines a center axis A and the inlet cone 44, first exhaust gas
treatment element 36, second exhaust gas treatment element 38, and
outlet cone 48 are coaxial with the center axis A.
[0040] At least one resonator connection 52 is in communication
with the resonator volume 42 within the resonator housing 43. The
component housing 32 comprises a center housing portion 54 that
encloses the first 36 and second 38 gas treatment elements, an
inlet portion 56 that is positioned at one end of the center
housing portion 54 to surround the inlet cone 44, and an outlet
portion 58 that is positioned at an opposite end of the center
housing portion 54 to surround the outlet cone 48. At least one
resonator connection 52 is in communication with the resonator
volume 42. In the example shown in FIG. 2, the resonator connection
52 comprises a Helmholtz neck that is positioned at the gap 40 and
is in communication with Helmholtz resonator volume 42. Optionally,
or in addition to, the connection point of the resonator connection
52 could be at the inlet 44 or outlet 48 cone as indicated with
dashed lines in FIG. 2.
[0041] In each of these different configurations, the configuration
is sealed such that there is no net flow in the Helmholtz
resonator. Hot engine exhaust gas flows in through the inlet pipe
46, expands and slows down as the gas travels through inlet cone
44, passes through the first exhaust gas treatment element 36, and
then expands into the gap 40 between the first 36 and second 48
exhaust gas treatment elements. The Helmholtz resonator connection
52 and resonator volume 42 are in parallel with the flow connected
at the gap 40. The exhaust gas then contracts and passes through
the second exhaust gas treatment element 38 and then expands into
the outlet cone 48 before contracting and exiting through the
outlet pipe 50.
[0042] The exhaust gas pressure pulsations from the engine travel
down through the exhaust system 10 and are modified as they travel
through the mechanisms of restriction, reflection, and absorption.
When the pulsations reach the gap 40 they cause the exhaust gas in
the resonator neck/connection 52 to start moving. For low
frequencies this gas can be considered as a lumped mass. The lumped
mass of gas in the resonator neck 52 compresses or rarifies the
exhaust gas in the surrounding resonator volume 42. As the lumped
mass of gas compresses the resonator volume 42, the volume pressure
increases. As the lumped mass of gas rarifies, the volume pressure
decreases. The result of this pressure is to push the lumped mass
in the opposite direction to which it is travelling. In this way,
the resonator volume 42 is acting as a spring and provides a
spring-mass system with a tuned frequency. As there is no net flow
through the Helmholtz resonator, and as the resonator neck 52
comprises a side-branch arrangement, the impact on back pressure is
negligible.
[0043] In the example shown in FIG. 2, the resonator volume 42 is
formed between an inner surface of the resonator housing 43 and an
outer surface of the component housing 32. The resonator volume 42
is concentric with the center axis A such that the resonator
housing 43 and resonator volume 42 completely and entirely
surrounds an outer circumference of the first 36 and second 38 gas
treatment elements. FIG. 3 shows an example that is similar to FIG.
2 but which comprises an offset configuration. In this example, the
resonator volume 42' is offset relative to the component housing 32
such that the resonator housing 43 and resonator volume 42' only
partially surrounds an outer circumference of the first 36 and
second 38 gas treatment elements.
[0044] FIG. 4 shows another example configuration. In this example,
a resonator volume 60 is removed from the component 30 and is
connected to the component housing 32 by at least one pipe 62. The
resonator volume 60 is enclosed within a resonator housing 64 and
the pipe 62 connects the resonator housing 64 to the component 30.
As such, the resonator housing 64 and volume 60 are located
externally of the component housing 32.
[0045] In the example shown in FIG. 4, the pipe 62 connects the
resonator housing 64 to the inlet portion 56 of the component
housing 32. The pipe 62 also optionally connects to the outlet
portion 58; however, the inlet portion 56 is preferred as it is
located closer to the engine 12. Optionally, or in addition to, an
additional pipe or a branch from the pipe 62 could connect the
volume 60 to the center housing portion 54 and one of the inlet 56
or outlet 58 portions. FIG. 5A shows an example where the external
volume 60 is connected to the inlet pipe 46. FIG. 5B shows an
example where the external volume 60 is connected to the center
housing portion 54 and is in communication with the gap 40. FIG. 5C
shows an example where the external volume 60 is connected to the
outlet pipe 50.
[0046] FIGS. 6A-6C show examples of an internal resonator volume 70
that is in series with the first 36 and second 38 exhaust gas
treatment elements. FIG. 6A shows an example where the volume 70 is
upstream of the first exhaust gas treatment element 36. FIG. 6B
shows an example where the volume 70 is upstream of the second
exhaust gas treatment element 38 and downstream of the gap 40. FIG.
6C shows an example where the volume 70 is downstream of the second
exhaust gas treatment element 38.
[0047] In another example shown in FIG. 7, the first 36 and second
38 gas treatment elements are enclosed within a common housing 80.
In this configuration, the first 36 and second 38 exhaust gas
treatment elements are non-coaxial and parallel with each other,
and are connected by a gap 82 such that exhaust gas exits the first
exhaust gas treatment element 36, enters the gap 82, and then
enters the second exhaust gas treatment element 38. A plurality of
resonator volumes 84 are provided within the housing 80. A
plurality of resonator connections 86 are also provided. The
housing 80 includes a baffle 88 with an inlet resonator volume 90
coupled to an inlet pipe 92 and an outlet resonator volume 94
coupled to an outlet pipe 96. The housing 80 also includes a second
baffle 98 to define a resonator volume at the gap 82.
[0048] Possible locations for the resonator connections 86 are at
the inlet resonator volume 90, at the outlet resonator volume 94,
and at the resonator volume at the gap 82. The resonator connection
86 associated at the gap 82 can be at a location between the
elements 36, 38, at an exit from the first exhaust gas treatment
element 36, and/or at an entrance to the second exhaust gas
treatment element 38. The resonator connections 86 can be used in
any number, and in any combination, as needed to provide the
desired acoustic effect.
[0049] The subject invention combines a tuning element with the
primary function of acoustic attenuation with a component in the
hot end 14 of the exhaust system 10 at a location that is much
closer to the pressure anti-node at the engine exhaust outlet than
traditional configurations. This provides improved acoustic
efficiency with negligible back pressure impact resulting in
tailpipe noise/acoustic volume improvement.
[0050] Although an embodiment of this invention has been disclosed,
a worker of ordinary skill in this art would recognize that certain
modifications would come within the scope of this invention. For
that reason, the following claims should be studied to determine
the true scope and content of this invention.
* * * * *