U.S. patent application number 11/964062 was filed with the patent office on 2009-05-21 for passive valve and resonator assembly for vehicle exhaust system.
Invention is credited to Kwin Abram, Ivan Arbuckle, James Egan, Kamilla Iskenderova, Dennis Shaw.
Application Number | 20090127022 11/964062 |
Document ID | / |
Family ID | 40640528 |
Filed Date | 2009-05-21 |
United States Patent
Application |
20090127022 |
Kind Code |
A1 |
Abram; Kwin ; et
al. |
May 21, 2009 |
PASSIVE VALVE AND RESONATOR ASSEMBLY FOR VEHICLE EXHAUST SYSTEM
Abstract
An exhaust system includes first and second exhaust components
with an inter-pipe that fluidly connects an outlet of the first
exhaust component to an inlet of the second exhaust component. A
passive valve is mounted within the inter-pipe. The second exhaust
component defines an internal cavity that is at least partially
packed with a high frequency absorption material and cooperates
with the passive valve to effectively attenuate low and high
frequency noise.
Inventors: |
Abram; Kwin; (Columbus,
IN) ; Arbuckle; Ivan; (Columbus, IN) ;
Iskenderova; Kamilla; (Columbus, IN) ; Egan;
James; (Indianapolis, IN) ; Shaw; Dennis;
(Columbus, IN) |
Correspondence
Address: |
PAMELA A. KACHUR
950 W 450 S, BLDG. 4
COLUMBUS
IN
47201
US
|
Family ID: |
40640528 |
Appl. No.: |
11/964062 |
Filed: |
December 26, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60989508 |
Nov 21, 2007 |
|
|
|
Current U.S.
Class: |
181/211 ;
181/228 |
Current CPC
Class: |
F02D 9/04 20130101; F02D
9/1065 20130101; F01N 2240/36 20130101; F01N 2260/06 20130101; F02D
9/1025 20130101; F01N 1/02 20130101; F01N 13/08 20130101 |
Class at
Publication: |
181/211 ;
181/228 |
International
Class: |
F01N 5/00 20060101
F01N005/00; F01N 7/08 20060101 F01N007/08 |
Claims
1. A vehicle exhaust system comprising: a first exhaust component
having a first inlet and a first outlet; a second exhaust component
positioned downstream of said first exhaust component, wherein said
second exhaust component defines an internal cavity with a second
inlet and a second outlet, said internal cavity being at least
partially packed with a high frequency absorption material; an
inter-pipe connecting said first outlet with said second inlet; and
a passive valve mounted within said inter-pipe.
2. The vehicle exhaust system according to claim 1 wherein said
inter-pipe comprises the sole exhaust gas flow path between said
first outlet and said second inlet.
3. The vehicle exhaust system according to claim 1 wherein said
first and said second exhaust components comprise first and second
resonators.
4. The vehicle exhaust system according to claim 3 including a
tailpipe in fluid communication with said second outlet.
5. The vehicle exhaust system according to claim 1 wherein said
second inlet and said second outlet cooperate to define a flow path
through said second exhaust component.
6. The vehicle exhaust system according to claim 5 wherein said
flow path is defined by a pipe diameter and wherein said passive
valve is mounted within the inter-pipe at a distance from said
second inlet of said second exhaust component that is at least four
times said pipe diameter.
7. The vehicle exhaust system according to claim 6 wherein said
flow path comprises a sole flow path through said second exhaust
component.
8. The vehicle exhaust system according to claim 7 wherein said
sole flow path occupies a portion of said internal cavity of said
second exhaust component leaving a remaining portion of said
internal cavity, and wherein said remaining portion of said
internal cavity is completely packed with said high frequency
absorption material.
9. The vehicle exhaust system according to claim 1 wherein said
passive valve comprises a vane supported on a shaft for pivotable
movement within said inter-pipe between an open position and a
closed position, and a spring that biases said vane toward said
closed position, said vane being pivotal from said closed position
towards said open position in response to an exhaust gas flow that
exceeds a biasing force of said spring.
10. The vehicle exhaust system according to claim 1 including a
pipe extending from said second inlet to said second outlet to
define a sole flow path through said second exhaust component, said
pipe including a perforated section positioned within said internal
cavity, and wherein said high frequency absorption material is
positioned to contact at least a portion of said perforated section
to provide a packed second exhaust component.
11. The vehicle exhaust system according to claim 10 wherein said
high frequency absorption material contacts an entire length of
said perforated section to provide said packed second exhaust
component.
12. The vehicle exhaust system according to claim 10 including at
least one tuning tube positioned within said internal cavity and in
communication with said pipe.
13. A vehicle exhaust system comprising: a first exhaust component
having a first inlet and a first outlet; a second exhaust component
defining an internal cavity having a second inlet and a second
outlet that cooperate to define an internal flow path through said
second exhaust component,; a pipe extending from said second inlet
to said second outlet to define said internal flow path as a sole
flow path through said second exhaust component; high frequency
absorption material positioned within said internal cavity to
contact at least a portion of said pipe to provide a packed second
exhaust component; an inter-pipe connecting said first outlet with
said second inlet; and a passive valve mounted within said
inter-pipe.
14. The vehicle exhaust system according to claim 13 wherein said
pipe occupies a portion of said internal cavity leaving a remaining
portion, and wherein said remaining portion of said internal cavity
is completely packed with a high frequency absorption material to
provide said packed second exhaust component.
15. The vehicle exhaust system according to claim 14 wherein said
first and said second exhaust components comprise first and second
mufflers and wherein said inter-pipe comprises a sole exhaust gas
flow path between said first outlet and said second inlet.
16. The vehicle exhaust system according to claim 13 wherein said
pipe is defined by a pipe diameter and wherein said passive valve
is mounted within said inter-pipe at a distance from said second
inlet of said second exhaust component that is at least four times
said pipe diameter.
17. The vehicle exhaust system according to claim 13 including a
tailpipe fluidly connected to said second outlet of said second
muffler.
18. The vehicle exhaust system according to claim 13 wherein said
passive valve comprises a vane supported on a shaft for pivotable
movement within said inter-pipe between an open position and a
closed position, and a spring that biases said vane toward said
closed position, said vane being pivotal from said closed position
towards said open position in response to an exhaust gas flow that
exceeds a biasing force of said spring.
19. The vehicle exhaust system according to claim 13 wherein said
pipe includes a perforated section positioned within said internal
cavity, and wherein said high frequency absorption material is
positioned to contact at least a portion of said perforated section
to provide said packed second exhaust component.
20. The vehicle exhaust system according to claim 19 wherein said
high frequency absorption material contacts an entire length of
said perforated section to provide said packed second exhaust
component.
21. The vehicle exhaust system according to claim 13 wherein said
first exhaust component comprises a first resonator and said packed
second exhaust component comprises a packed second resonator, and
wherein said inter-pipe comprises a sole exhaust gas flow path
between said first outlet and said second inlet, said passive valve
being mounted within said inter-pipe at a predetermined fixed
distance from said second inlet of said packed second
resonator.
22. The vehicle exhaust system according to claim 21 wherein said
pipe of said packed second resonator is defined by a pipe diameter,
and wherein said predetermined fixed distance is four times said
pipe diameter.
23. The vehicle exhaust system according to claim 1 wherein said
first exhaust component comprises a first resonator and said second
exhaust component comprises a packed second resonator, and wherein
said inter-pipe comprises a sole exhaust gas flow path between said
first outlet and said second inlet, said passive valve being
mounted within said inter-pipe at a predetermined fixed distance
from said second inlet of said packed second resonator.
24. The vehicle exhaust system according to claim 23 including a
pipe extending from said second inlet to said second outlet to
define a sole internal flow path through said packed second
resonator, said pipe being defined by a pipe diameter, and wherein
said predetermined fixed distance is four times said pipe diameter.
Description
RELATED APPLICATIONS
[0001] This application claims priority to provisional application
No. 60/989,508 filed on Nov. 21, 2007.
TECHNICAL FIELD
[0002] The subject invention relates to a passive valve and
resonator configuration in a vehicle exhaust system, and more
particularly relates to a passive valve in combination with a
packed resonator.
BACKGROUND OF THE INVENTION
[0003] Exhaust systems are widely known and used with combustion
engines. Typically, an exhaust system includes exhaust tubes that
convey hot exhaust gases from the engine to other exhaust system
components, such as mufflers, resonators, etc. Mufflers and
resonators include acoustic chambers that cancel out sound waves
carried by the exhaust gases. Although effective, these components
are often relatively large in size and provide limited nose
attenuation.
[0004] Passive valves have been used in a muffler to provide
further noise attenuation. However, the proposed valves have
numerous drawbacks that limit their widespread use in a variety of
applications. One disadvantage with passive valves is their limited
use in high temperature conditions. Another disadvantage with known
passive valve configurations is that these valves do not
effectively attenuate low frequency noise. Further, additional
challenges are presented when these types of valves are used in
exhaust systems with multiple mufflers.
[0005] Attempts have been made to improve low frequency noise
attenuation without using passive valves by either increasing
muffler volume or increasing backpressure. Increasing muffler
volume is disadvantageous from a cost, material, and packaging
space perspective. Increasing backpressure can adversely affect
engine power. Thus, solutions are needed to more effectively
incorporate passive valves within an overall exhaust system.
[0006] Still other attempts have been made to use the passive valve
in the exhaust system at a location outside of a muffler. For
example, the passive valve has been used within an exhaust pipe
with a by-pass configuration. The passive valve includes a flapper
valve body or vane that is positioned within the exhaust pipe, with
the vane being pivotable between an open position and a closed
position. The passive valve is spring biased toward the closed
position, and when exhaust gas pressure is sufficient to overcome
this spring bias, the vane is pivoted toward the open position. In
by-pass configurations, the vane provides 100% coverage, i.e.
complete blockage, of the exhaust component when in the closed
position. When closed, exhaust gases can flow outside of the
exhaust pipe that houses the vane via a by-pass pipe that is
connected to the exhaust pipe at locations upstream and downstream
of the vane. The vane is generally configured such that, during
pivotal movement, edges of the vane do not contact inner surfaces
of the exhaust component. While use of such a valve improves low
frequency noise attenuation, there is additional flow noise caused
by turbulence generated at edges of the vane. Thus, while using the
passive valve outside of the muffler has addressed certain
problems, it has raised additional noise challenges that need to be
addressed.
[0007] Therefore, there is a need to provide a passive valve
arrangement that can effectively attenuate low frequency noises
while also addressing additional noise issues introduced by the use
of the passive valve itself. This invention addresses those needs
while avoiding the shortcomings and drawbacks of the prior art.
SUMMARY OF THE INVENTION
[0008] A vehicle exhaust system includes first and second exhaust
components with an inter-pipe that fluidly connects an outlet of
the first exhaust component to an inlet of the second exhaust
component. A passive valve is mounted within the inter-pipe. The
second exhaust component defines an internal cavity that is at
least partially packed with a high frequency absorption material.
This packed configuration cooperates with the passive valve to
effectively attenuate low and high frequency noise.
[0009] In one example, the first and the second exhaust components
comprise first and second mufflers or resonators and the inter-pipe
comprises a sole exhaust gas flow path between the first outlet and
the second inlet.
[0010] In one example, the first exhaust component has a first
inlet and a first outlet, and the second exhaust component defines
an internal cavity that has a second inlet and a second outlet. The
second inlet and the second outlet cooperate to define an internal
flow path through the second exhaust component. The internal flow
path occupies a portion of the internal cavity leaving a remaining
portion. The remaining portion of the internal cavity is completely
packed with a high frequency absorption material. The inter-pipe
connects the first outlet with the second inlet, and the passive
valve is mounted within the inter-pipe.
[0011] In one example, the second exhaust component includes a pipe
that connects the second inlet to the second output to define the
internal flow path. The pipe is defined by a pipe diameter and the
passive valve is mounted within the inter-pipe at a specified
distance from the second inlet of the second exhaust component. In
one example, this specified distance is a distance that is at least
four times the pipe diameter of the internal flow path.
[0012] In one example, the pipe includes a perforated section and
the high frequency absorption material is positioned within the
internal cavity to contact at least a portion of the perforated
section. In one example, the high frequency absorption material
contacts an entire length of the perforated section.
[0013] The above-described combination of a passive valve and an
associated packed muffler cooperate to effectively attenuate low
and high frequency noises. The use of the passive valve within a
non-bypass inter-pipe provides very effective low frequency noise
attenuation while the use of the packed rear positioned muffler
addresses noise issues created due to the passive valve location
and configuration. These and other features of the present
invention can be best understood from the following specification
and drawings, the following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 shows a perspective view of an exhaust pipe component
and passive assembly.
[0015] FIG. 2 shows one example of a passive valve in a vehicle
exhaust system.
[0016] FIG. 3 shows a cross-sectional view of a rearmost exhaust
component from FIG. 2.
[0017] FIG. 4 shows a schematic view of a mounting location of the
passive valve in relation to the exhaust component of FIG. 3.
[0018] FIG. 5 is a schematic view of one example of a packed
exhaust component with a perforated pipe.
[0019] FIG. 6 is a schematic view of another example of a packed
exhaust component with a tuning pipe.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] As shown in FIG. 1, an exhaust component, such as an exhaust
tube or pipe 10 includes an exhaust throttling valve, referred to
as a passive valve assembly 12. The passive valve assembly 12 is
movable between an open position where there is minimal blockage of
an exhaust gas flow path 16 and a closed position where a
substantial portion of the exhaust gas flow path 16 is blocked. The
passive valve assembly 12 is resiliently biased toward the closed
position and is moved toward the open position when exhaust gas
flow generates a pressure sufficient enough to overcome the biasing
force.
[0021] In the example shown, the exhaust pipe 10 comprises a single
tube body 14 that defines the exhaust gas flow path 16. The passive
valve assembly 12 includes a valve body or vane 18 that blocks a
portion of the exhaust gas flow path 16 when in the closed
position. As discussed above, the vane 18 is pivoted toward the
open position to minimize blockage of the exhaust gas flow path 16
in response to pressure exerted against the vane 18 by exhaust
gases.
[0022] In one example, the vane 18 is fixed to a shaft 20 with a
tang or bracket 22. A slot 24 is formed within an outer surface of
the tube body 14. A housing 26, shown in this example as a square
metal structure, is received within this slot 24 and is welded to
the tube body 14. Other housing configurations could also be used.
The shaft 20 is rotatably supported within the housing 26 by first
28 and second 30 bushings or bearings. In the example shown, the
bracket 22 comprises a piece of sheet metal that has one portion
welded to the shaft 20 and another portion that extends outwardly
from the housing 26 and is welded to the vane 18. Thus, the vane 18
and the shaft 20 pivot together about an axis A that is defined by
the shaft 20. The bracket 22 is just one example of how the shaft
20 can be attached to the vane 18, it should be understood that
other attachment mechanisms could also be used.
[0023] The first bushing 28 is positioned generally at a first
shaft end 32. The first bushing 28 comprises a sealed interface for
the first shaft end 32. The shaft 20 includes a shaft body 34 that
has a first collar 36 and a second collar 38. The first bushing 28
includes a first bore that receives the first shaft end 32 such
that the first collar 36 abuts directly against an end face of the
first bushing 28 to provide a sealed interface. As such, exhaust
gases cannot leak out of the first bushing 28 along a path between
the shaft 20 and first bushing 28.
[0024] The second bushing 30 includes a second bore through which
the shaft body 34 extends to a second shaft end 40. The second
collar 38 is located axially inboard of the second bushing 30. The
shaft 20 extends through the second bore to an axially outboard
position relative to the second bushing 30. A resilient member,
such as a spring 42 for example, is coupled to the second shaft end
40 with a spring retainer 44. The spring retainer 44 includes a
first retainer piece 46 that is fixed to the housing 26 and a
second retainer piece 48 that is fixed to the second shaft end 40.
One spring end 50 is associated with housing 26 via the first
retainer piece 46 and a second spring end (not viewable in FIG. 1
due to the spring retainer 44) is associated with the shaft 20 via
the second retainer piece 48.
[0025] The passive valve assembly 12 is advantageously positioned
within a vehicle exhaust system at a certain positional
relationship to other exhaust components to provide a significant
acoustic advantage for overall noise attenuation. FIG. 2
schematically shows a vehicle exhaust system 60 that includes at
least one first resonator or muffler 62 and at least one second
resonator or muffler 64. The first muffler 62 has an inlet 66 that
receives exhaust gas flow from an engine as indicated at 68. The
first muffler 62 includes an outlet 70 that directs exhaust gases
to an inter-pipe 72.
[0026] The inter-pipe 72 fluidly connects the outlet 70 of the
first muffler to an inlet 74 of the second muffler 64. The second
muffler 64 includes an outlet 76 that is fluidly connected to a
tailpipe 78. The inter-pipe 72 can be a single tube or can be
comprised of multiple tube portions connected together to form a
single tube between the first 62 and second 64 mufflers. Similarly,
the tailpipe 78 can be a single tube or can be comprised of
multiple tube portions connected together to form a single flow gas
exit from the exhaust system 60.
[0027] The inter-pipe 72 forms the sole exhaust gas flow path
between the first 62 and second 64 mufflers. In other words, there
is no by-pass flow option within the fluid connections between the
first 62 and second 64 mufflers. As such, the inter-pipe 72 extends
from a first end 80 to a second end 82 to define an overall pipe
length referred to as a developed length of the pipe. The first 80
and second 82 ends need not be co-axial, thus the developed length
of the pipe can be comprised of a single straight section of pipe
or can be comprised of a combination of straight and curved
sections of pipe having their lengths added together.
[0028] The passive valve assembly 12 is mounted external to the
first 62 and second mufflers 64 and within the inter-pipe 72. The
passive valve assembly 12 is positioned within the inter-pipe 72
between the first 80 and second 82 ends at a specified location in
relation to the second muffler 64. This will be discussed in
greater detail below.
[0029] FIG. 3 shows a cross-sectional view of the second muffler
64. The second muffler 64 defines an internal cavity 90 that has a
single inlet 74 and a single outlet 76. The inlet 74 and outlet 76
cooperate to define the sole flow path 92 within the second muffler
64. This flow path 92 occupies a specified portion of the internal
cavity 90 leaving a remaining portion that is not occupied by the
flow path 92. This remaining portion is packed with a high
frequency absorption material 94. In one example a fiber-based
material is used, however, any suitable material for attenuating
high frequency noise can be used.
[0030] In the example shown, the sole flow path 92 is contained
within a pipe body 96 that extends from the inlet 74 to the outlet
76, and the high frequency absorption material 94 completely fills
the internal cavity 90 to completely surround the pipe body 96.
This completely packed configuration is the most common
configuration and is the most efficient configuration from an
assembly and manufacture perspective.
[0031] As shown in FIG. 4, the passive valve assembly 12 is mounted
within the inter-pipe 72 at a specified location relative to the
inlet 74 of the second muffler 64 as indicated at 98. The pipe body
96 is defined by a pipe diameter D. This pipe diameter D can vary
depending upon the type of vehicle application and/or other exhaust
system characteristics. The passive valve assembly 12 is positioned
at a distance that is at least four times the pipe diameter D that
defines the flow path 92. By locating the passive valve assembly 12
in such a relation to the inlet 74 of the packed second muffler 64,
absorption of flow noise is maximized due to distances involved in
generate of flow noise from a geometric step change.
[0032] In another example shown in FIG. 5, a pipe 100 extends from
the inlet 74 to the outlet 76 to define a sole flow path 102. The
pipe 100 includes a perforated section 104. The perforated section
104 is positioned within the internal cavity 90 and extends along a
portion of an overall length of the pipe 100. As such, a length L
of the perforated section 104 is less than the overall length of
the pipe 100. The perforated section 104 at least partially extends
about an outer circumference of the pipe 100, and in the example
shown, extends entirely about the outer circumference of the pipe
100.
[0033] The high frequency absorption material 94 is positioned with
the internal cavity 90 to contact at least a portion of the
perforated section 104 to provide a packed configuration. In the
example shown, the high frequency absorption material 94 is
positioned to contact the entire length L of the perforated section
104. The high frequency absorption material 94 can comprise
material that is packed around the pipe to provide this contact, or
the high frequency absorption material 94 can comprise a mat that
is wrapped around the perforated section 104.
[0034] In the example shown in FIG. 5, the high frequency
absorption material 94 also contacts the pipe 100 along
non-perforated sections 106. Further, the pipe 100 can also include
sections within the internal cavity 90 that are not in contact with
high frequency absorption material 94. However, as described above,
in each example the high frequency absorption material 94 does
contact the entire length L of the perforated section 104 to
provide the most effective attenuation of high frequency noise.
[0035] In the example shown in FIG. 6, a tuning tube 108 is
connected to the pipe 100 at one of the non-perforated sections 106
to provide additional noise attenuation. In this example, the high
frequency absorption material 94 is not at a location of the pipe
100 that is contact with high frequency absorption material 94.
However, high frequency absorption material 94 could also be used
on the pipe 100 at the tuning tube location. Further, the tuning
tube 108 could also be used in the configuration shown in FIGS.
2-4.
[0036] For the configurations set forth in FIGS. 5 and 6, the
passive valve assembly 12 is mounted within the inter-pipe 72 at a
specified location relative to the inlet 74 of the second muffler
64 as described above in the examples of FIGS. 2-4. Also, the pipe
body 96 shown in FIGS. 3 and 4 could include a perforated section
in combination with a completely packed internal cavity.
[0037] The use of a packed high frequency muffler downstream of a
throttling, spring-biased passive valve provides an effective
configuration for attenuating noise. The passive valve assembly 12,
which is effective for attenuating low frequency noises, cooperates
with the packed muffler, which is effective for attenuating high
frequency noise, to provide an exhaust system with significantly
improved noise attenuation capability.
[0038] Although a preferred 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.
* * * * *