FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10; rule 13]
TITLE: “A SOUND ATTENUATION DEVICE FOR A VEHICLE EXHAUST
SYSTEM”
Name and Address of the Applicant: TATA MOTORS PASSENGER VEHICLES LIMITED; of Floor 3, 4, Plot-18, Nanavati Mahalaya, Mudhana Shetty Marg, BSE, Fort, Mumbai, Mumbai City, Maharashtra, 400001.
Nationality: Indian
The following specification particularly describes the nature of the invention and the manner in which it is to be performed.

TECHNICAL FIELD
[001] Present disclosure generally relates to a field of automobiles. Particularly, but not exclusively, the present disclosure relates to sound attenuation devices for an exhaust system of a vehicle.
BACKGROUND OF THE DISCLOSURE
[002] Typically, different types of vehicles such as passenger vehicles and commercial vehicles, include an exhaust system. The exhaust system is connected to an internal combustion engine and collects exhaust gases discharged from an outlet of an engine cylinder(s). These exhaust gases are also passed through after-treatment systems which are configured to treat the exhaust gases before releasing them into the surrounding environment. Typically, the exhaust system includes a pre-silencer and a post silencer/a muffler, a middle pipe and a tail pipe, each structured in different cross-sections. The pre-silencer is connected to the middle pipe and the muffler is connected to the tail pipe. The middle pipe is connected to an exhaust manifold which is coupled to an engine and directs hot exhaust gases from the engine into the pre-silencer. During the release of exhaust gas from the exhaust manifold, a plurality of incident waves and reflective waves of the acoustic energy are generated. As the exhaust manifold, pipe and muffler have varying cross sections, the incident waves and the reflective waves constructively interfere with each other and generates a standing wave(s) having low frequency. These low frequency standing waves or acoustic waves generate noise from the exhaust system which is uncomfortable and irritating to the occupants. The pre-silencer reduces noise level by breaking the standing waves or acoustic waves. The exhaust gases are directed from the pre-silencer to the muffler for attenuating sound & purifying harmful substances present in the exhaust gasses through a catalytic conversion.
[003] Conventionally, the pre-silencer comprises a perforated tube or baffles that is surrounded by a glass-wool which is further covered by a metallic outer shell or a housing. Acoustic energy is generated in the form of waves upon release of exhaust gases from the exhaust manifold with high pressure flow through the perforations of the perforated tube and these acoustic waves are absorbed by the glass wool. The glass wool attenuates the acoustic energy to reduce noise level and the metallic outer shell is used for transfer of heat from the exhaust gasses. However due to prolonged use of the pre-silencer, the glass wool gets deteriorated, and the required noise reduction is not achieved. Moreover, Noise, vibration, and

harshness (NVH) performance of the vehicle is compromised. Also, the glass wool of the pre-silencer must be frequently replaced to achieve required noise reduction which result in high maintenance costs. Also, weight of the exhaust system with the pre-silencer configuration and the muffler is considerably high which increases overall weight of the vehicle. Consequently, there is increase in fuel consumption and reduction in overall efficiency of the engine.
[004] The present disclosure is directed to overcome one or more limitations stated above or other such limitations associated with the prior art.
SUMMARY OF THE DISCLOSURE
[005] One or more shortcomings of conventional systems are overcome, and additional advantages are provided through a system, and a device as claimed in the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered as a part of the claimed disclosure.
[006] In one non-limiting embodiment of the disclosure, a sound attenuation device for a vehicle exhaust system is disclosed. The device comprises a body defined with a corrugated structure. An internal passage is configured to allow flow of an exhaust gas and acoustic waves generated within the vehicle exhaust system. An inlet is defined at a first end of the body and an outlet is defined at a second end opposite to the first end of the body. The inlet is connectable to an exhaust manifold of an engine of the vehicle and the outlet is connectable to a muffler of the vehicle exhaust system. Further, the corrugated structure comprises a plurality of crests and a plurality of troughs which are configured to generate interference to the flow of the acoustic waves to attenuate acoustic energy.
[007] In an embodiment of the disclosure, the plurality of crests and the plurality of troughs are alternately arranged along a length of the body and configured to extend radially outward from a portion of the body.
[008] In an embodiment of the disclosure, each crest of the plurality of crests and each trough of the plurality of troughs is defined with a convex edge opposite to each other along a longitudinal direction of the body.

[009] In an embodiment of the disclosure, the corrugated structure extends spirally along a length of the body.
[010] In an embodiment of the disclosure, the body is defined with a minimum diameter between the portion of the body from which the plurality of crests and the plurality of troughs extend radially from the body.
[011] In an embodiment of the disclosure, the corrugated structure comprises at least one of a square edge, a circular edge, triangular edge, elliptical edge, a rectangular edge, a polygonal edge and any combination thereof.
[012] In an embodiment of the disclosure, the plurality of alternating crests and troughs (12) are structured with a pitch ranging between 10 to 100 mm.
[013] In another non-limiting embodiment of the disclosure, an exhaust system for a vehicle is disclosed. The system comprises a muffler and a sound attenuation device. The sound attenuation device is disposed in fluid communication between an exhaust manifold of an engine of the vehicle and the muffler. The sound attenuation device comprises a body defined with a corrugated structure. An internal passage is configured to allow flow of an exhaust gas and acoustic waves generated within the vehicle exhaust system. An inlet is defined at a first end of the body and an outlet is defined at a second end opposite to the first end of the body. The inlet is to be connected to the exhaust manifold and the outlet is connected to the muffler of the vehicle exhaust system. Further, the corrugated structure comprises a plurality of crests and a plurality of troughs which are configured to generate interference to the flow of the acoustic waves to attenuate acoustic energy before transfer of the exhaust gas to the muffler.
[014] In another non-limiting embodiment of the disclosure, a vehicle is disclosed. The vehicle comprises an engine, an exhaust manifold connected to the engine and a muffler. A sound attenuation device is disposed in fluid communication between the exhaust manifold and the muffler. The sound attenuation device comprises a body defined with a corrugated structure. An internal passage is configured to allow flow of an exhaust gas and acoustic waves generated within the vehicle exhaust system. An inlet is defined at a first end of the body and an outlet is defined at a second end opposite to the first end of the body. The inlet is connected to the exhaust manifold and the outlet is connected to the muffler. Further, the corrugated structure comprises a plurality of crests and a plurality of troughs which are configured to

generate interference to the flow of the acoustic waves to attenuate acoustic energy before transfer of the exhaust gas to the muffler.
[015] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined together to form a further embodiment of the disclosure.
[016] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[017] The novel features and characteristics of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an embodiment when read in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings wherein like reference numerals represent like elements and in which:
Fig. 1 illustrates a front perspective view of an exhaust system for a vehicle with a sound attenuation device, in accordance with an embodiment of the present disclosure.
Fig. 2a illustrates a front perspective view of an exhaust system for a vehicle with another embodiment of the sound attenuation device, in accordance with an embodiment of the present disclosure.
Fig. 2b illustrates an exploded perspective view of the exhaust system of Fig. 2a.
Fig. 3a illustrates a front view of the sound attenuation device in accordance with an embodiment of the present disclosure.
Fig. 3b illustrates a side view of the sound attenuation device of Fig. 3a.
Fig. 4a illustrates a front sectional view of the sound attenuation device in accordance with an embodiment of the present disclosure.

Fig. 4b illustrates an enlarged view of a portion of Fig. 4a depicting a flow pattern of acoustic waves and exhaust gas within the sound attenuation device.
Fig. 5a illustrates a schematic view of another embodiment of the sound attenuation device.
Fig. 5b illustrates a front sectional view of the sound attenuation device of Fig. 5a.
Fig. 6a illustrates a bottom view of a vehicle with the exhaust system of Fig. 1; and
Fig. 6b illustrates the bottom view of a vehicle with the exhaust system of Fig. 2a.
[018] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[019] While the embodiments in the disclosure are subject to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the figure and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.
[020] It is to be noted that a person skilled in the art would be motivated from the present disclosure and modify various features of a device, a system and a method without departing from the scope of the disclosure. Therefore, such modifications are considered to be part of the disclosure. Accordingly, the drawings show only those specific details that are pertinent to understand the embodiments of the present disclosure, so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skilled in the art having benefit of the description herein. Also, the device and the system of the present disclosure may be employed in various vehicles having different specifications.
[021] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that of the device or the system that comprises a list of components does not include only those components but may include

other components not expressly listed or inherent to such device, or the system. In other words, one or more elements in the device or the system proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the device and the system.
[022] Embodiments of the present disclosure discloses a sound attenuation device for a vehicle exhaust system. The sound attenuation device comprises a body defined with a corrugated structure. An internal passage is configured to allow flow of an exhaust gas and acoustic waves generated within the vehicle exhaust system. An inlet is defined at a first end of the body and an outlet is defined at a second end opposite to the first end of the body. The inlet is connectable to an exhaust manifold and the outlet is connectable to a muffler of the vehicle exhaust system. Further, the corrugated structure comprises a plurality of crests and a plurality of troughs which are configured to generate interference to the flow of the acoustic waves to attenuate acoustic energy.
[023] The following paragraphs describe the present disclosure with reference to Figs. 1 to 6b. In the figures, the same element or elements which have similar functions are indicated by the same reference signs.
[024] Referring to Figs. 1, 2a and 2b which illustrates front perspective views of an exhaust system (200) for a vehicle (300) [interchangeably referred to as “the system (200)”] in accordance with an embodiment of the present disclosure. The system (200) comprises an exhaust manifold. In an embodiment, the exhaust manifold may be integrated within an engine of the vehicle (300), and a muffler (206). A first conduit (202) is defined with a first inlet (205) and a first outlet (207) such that the first inlet (205) is connected to the engine, such as through the exhaust manifold. Further, a second conduit (204) is defined with a second inlet (209) and a second outlet (211), such that the second outlet (211) is connected to the muffler (206).
[025] A sound attenuation device (100) [hereafter referred to as the “device (100)”] is disposed in fluid communication between the engine and the muffler (206) through the first and second conduits (202, 204). An exhaust manifold, which may integrated within the engine, receives high temperature exhaust gas (117) (as shown in Fig. 4b) from the engine (61) along with acoustic waves (116) (as shown in Fig. 4b) that are generated upon release of the exhaust gas (117) at high pressure. The exhaust gas (117) and the acoustic waves (116) are configured

to flow through the first conduit (202), the device (100), the second conduit (204) and the muffler (206). In an embodiment, a catalytic converter (201) is disposed between the exhaust manifold and the first conduit (202) (as shown in Fig. 1). The exhaust gas (117) from the exhaust manifold is directed into the first conduit (202) through the catalytic convertor (201). The catalytic converter (201) is configured to diffuse harmful compounds present in the exhaust gas (117) coming from the engine (61) before transferring the exhaust gas (117) to the first conduit (202).
[026] Now referring to Figs. 3a and 3b, a front view and side view, respectively, of the device (100) are disclosed. The device (100) comprises a body (102) defined with an inlet (104) and an outlet (106). The inlet (104) is defined at a first end of the body (102) and the outlet (106) is defined at a second end which is opposite to the first end of the body. The inlet (104) is connectable to the exhaust manifold through the first conduit (202). The outlet (106) is connectable to the muffler (206) through the second conduit (204). The body (102) is defined with a corrugated structure (108) that extends between the inlet (104) and the outlet (106). The corrugated structure (108) is designed to comprise a plurality of crests (110) and a plurality of troughs (112) arranged alternately along a length of the body (102). In an embodiment, the plurality of crests (110) and the plurality of troughs (112) are structured to radially extend outward from a portion of the body (102). However, such structure cannot be construed as a limitation. The plurality of crests (110) and the plurality of troughs (112) may extend up to a required length based on the requirement.
[027] In an embodiment, the plurality of crests (110) extend in an upward direction and the plurality of troughs (112) extend in a downward direction from the portion of the body (102). The plurality of crests (110) and the plurality of troughs (112) is defined with a hollow inner surface for fluid flow within the corrugated structure (108). The body (102) is defined with a minimum diameter (d) (as shown in fig. 4a) between the portion of the body (102) from which the plurality of crests (110), and the plurality of troughs (112) extend in a radial direction of the body (102). In an example, the minimum diameter (d) corresponds to a distance between a portion of the body (102) from which each crest (110) extends radially away from the body (102), and to the portion of the body (102) from which each trough (112) extends radially from the body (102).
[028] Referring to Fig. 4a, the plurality of crests (110) and the plurality of troughs (112) are structured with a pitch ranging from 10 to 100 mm. Each crest (110) of the plurality of crests

(110) and each trough (112) of the plurality of troughs (112) is defined with a convex edge (130) and are positioned opposite to each other. Further, the convex edge (130) of each crest (110) of the plurality of crests (110) and each trough (112) of the plurality of troughs (112) correspond to a maximum diameter (D) of the body (102). In an embodiment, the corrugated structure (108) may comprise the plurality of crests (110) and the plurality of troughs (112) having a configuration of at least one of a square (as shown in Fig. 5a), a circular, a rectangular, and a triangular and in any polygonal shape. In an embodiment, the corrugated structure (108) comprises at least one of a square edge (132) (as shown in Fig. 5b), a circular edge, a triangular edge, a rectangular edge, an elliptical edge, any polygonal shaped edge. In another embodiment, the plurality of crests (110) and the plurality of troughs (112) may be structured to have a combination of any polygonal shape formed along the length of the device (100). In a preferred embodiment, the plurality of crests (110) and the plurality of troughs (112) extend spirally along the length of the body (102) in a longitudinal direction of the device (100).
[029] Now referring to Fig. 4b in conjunction with Fig. 4a, the body (102) is defined with an internal passage (114) within the portion of the body (102). The internal passage (114) is configured to allow flow of the exhaust gas (117) and acoustic waves (116) through the device (100). The internal passage (114) extends along the length of the body (102) and across the hollow inner surface of the plurality of crests (110) and the plurality of troughs (112). This provides a curved flow path (115) for the acoustic waves (116) and the exhaust gas (117) flowing through the internal passage (114). The acoustic waves (116) flowing through the internal passage (114) are redirected to a central portion (122) of the internal passage (114) upon contact with the plurality of crests (110) and the plurality of troughs (112). This causes the acoustic waves (116) to destructively interfere with each other at the central portion (122) (as shown in Fig. 4b) such that the acoustic waves (116) having similar frequency are zeroed out to attenuate the acoustic energy. This way, a noise generated from the acoustic waves (116) which are generated upon release of exhaust gas (117) from the exhaust manifold and the catalytic converter (201) is reduced while flowing through the device (100) from the inlet (104) towards the outlet (106). Similarly, the exhaust gas (117) flowing through the corrugated structure (108) is subjected to a pressure drop and decrease in temperature while passing through the plurality of crests (110) and the plurality of troughs (112).
[030] The device (100) may be manufactured by a hydroforming process. A high pressure hydraulic fluid is used to press a working or raw material at a room temperature into a die (not

shown in Figs.). As an example, to hydroform the device (100), a hollow tube of material is placed inside a negative mold (not shown in Figs.) that has the shape of the device (100). After positioning the material, high pressure hydraulic pumps then inject fluid at a very high pressure inside the hollow tube which causes it to expand until it matches the mold. The hydroformed structure or device (100) is then removed from the mold.
[031] In an exemplary embodiment, referring to figs. 2a and 2b, the exhaust system (200) may be equipped with the device (100a) which may be structured in a split configuration such that the plurality of crests (110) are configured to radially extend from a first plate (111a), also referred to as a top plate. The plurality of troughs (112) are configured to radially extend from a second plate (111b), also referred to as a bottom plate. The first plate (111a) and the second plate (111b) are assembled together to form the device (100) with the corrugated structure (108). In an embodiment, the first and second plates (111a, 111b) may be joined together by suitable fastening means such as bolts and nuts, welding, riveting etc.
[032] The device (100a) may be manufactured by a process of stamping and welding in sequence. Initially, the first plate (111a) and the second plate (111b) are formed by the stamping process individually. The stamping process includes shaping the first and second plates (111a, 111b) on a die (not shown in Figs.) having negative impression of the same. In an embodiment, the die may be in two pieces wherein a top die is pressed above a bottom die with the raw material therebetween. After stamping, the first plate (111a) and the second plate (111b) are joined together by welding process to manufacture the final device (100a). In an embodiment, the welding process can be selected from an arc welding, a tig welding or any suitable process. In an embodiment, the first and second plates (111a, 111b) may also be manufactured by the hydroforming process.
[033] Referring to Figs 5a and 5b, the device (100b) with the corrugated structure (108) in accordance with another embodiment is disclosed. The device (100b) comprises the body (102) defined with the internal passage (114), extending between the inlet (104) and the outlet (106) opposite to the inlet (104). The corrugated structure (108) is disposed between the inlet (104) and the outlet (106). The corrugated structure (108) is defined with a plurality of flow channels (113) extending radially from the portion of the body (102). In an embodiment, the plurality of flow channels (113) may be structured in a cylindrical shape, squared shape or a rectangular shape. The plurality of flow channels (113) positioned in a spaced apart configuration along the length of the body (102). The plurality of flow channels (113) extend radially outward from

the portion of the body (102) with a predefined radius along a predefined length of the body (102). In an embodiment, the predefined radius of the plurality of flow channels (113) is in a range of 30 to 120 mm and the predefined length ranges from 10 to 50 mm.. In an embodiment, each flow channel (113) of the plurality of flow channels (113) may be structured with a thickness ranging from 1 to 3 mm. Each flow channel (113) of the plurality of flow channels (113) is defined with a square edge (132) defined annular to the body (102). The plurality of flow channels (113) correspond to the plurality of crests (110) and the plurality of troughs (112). The plurality of flow channels (113) are defined with a hollow internal surface such that the acoustic waves (116) and the exhaust gas (117) flow through the hollow internal surface of the plurality of flow channels (113) to generate interference to the flow of acoustic waves (116) and the exhaust gas (117) to attenuate acoustic energy and to reduce temperature and pressure of the exhaust gas (117).
[034] Referring to figs. 6a and 6b, a bottom view of a vehicle (300) with the exhaust system (200) of the present disclosure is disclosed. The vehicle includes an engine (61), a frame assembly (62), a transmission assembly (63) and the exhaust system (200). The engine (61) comprises an inlet valve (not shown in Figs.) and an exhaust valve (not shown in Figs.). The exhaust system (200) is connected to the engine (61) whereby exhaust manifold is coupled to the exhaust valve of the engine (61). The exhaust system (200) comprises the first conduit (202), the device (100), the second conduit (204) and the muffler (206) connected sequentially in a longitudinal direction of the vehicle (300). The exhaust system (200) is mounted on the plurality of cross members (66) and fastened at various positions to fixedly assemble the exhaust system (200) to a chassis (60) of the vehicle (300). In an embodiment, the exhaust system (200) is fastened using a fastening means (65) which may include plurality of brackets.
[035] The working of the exhaust system (200) to attenuate the acoustic energy is now explained. The exhaust system (200) is coupled to a chassis (60) of the vehicle (300) with suitable fastening means (65) at various positions of the chassis (60). In an embodiment, the exhaust system (200) is mounted on a rubber hanger suspended from or connected to the chassis (60). Exhaust gas (117) having high temperature and pressure are produced during operation of the engine (61). The exhaust gas (117) is expelled from the exhaust valve (not shown in Figs.) and into the exhaust manifold. The acoustic waves (116) and the exhaust gas (117) enter from the inlet (104) and pass through the internal passage (114). The acoustic waves (116) are divided upon passing through the corrugated structure (108) such that some of the acoustic

waves (116) enter a first crest (110a) in one direction i.e. in an upward direction and the remaining acoustic waves (116) enter a first trough (112a) (as shown in Fig. 4b) in another direction i.e. in a downward direction opposite to the one direction. The acoustic waves (116) travel through the convex edge of the first crest (110a) and the first trough (112a) and are redirected to the central portion (122) of the internal passage (114). The acoustic waves (116) from the first crest (110a) collide with the acoustic waves (116) from the first trough (112a) (as shown at portion ‘a’ Fig. 4b) may undergo interference. This will result in elimination of the acoustic waves (116), resulting in attenuation of the acoustic energy. In other words, the acoustic waves (116) from the first crest (110a) may destructively interfere with those passing through the first trough (112a) of similar frequency to attenuate the acoustic energy. This attenuation of the acoustic energy happens throughout the flow of acoustic waves (116) within each crest of the plurality of crests (110) and each trough of the plurality of troughs (112).
[036] The flow of the exhaust gas (117) is now explained referring to fig. 4a. The exhaust gas (117) travel through the alternating crests (110) and troughs (112). While flowing through the first crest (110a), the exhaust gas (117) flows in a curved flow path (115) i.e. towards the convex edge (130) and away from the convex edge (130). Similarly, the exhaust gas (117) flows continuously throughout the plurality of alternating crests (110) and troughs (112). The flow of exhaust gas (117) in the upward and downward directions in each crest (110) and trough (112) increases the flow area of the exhaust gas (117) which results in the decrease in temperature and pressure of the exhaust gas (117). The low temperature exhaust gas (117) is discharged from the outlet (106) and allowed to pass through the second conduit (204). The exhaust gas (117) enters the second conduit (204) through the second inlet (209) and are directed to the muffler (206). Final diffusion of the exhaust gas (117) is carried out in the muffler (206) and the exhaust gas (117) is then discharged into the atmosphere. During the flow of the exhaust gas, volume of the exhaust gas (117) decreases proportionally with reducing temperature. Consequently, this reduces speed of the exhaust gas (117) flow inside the exhaust system also reduced, and thereby reducing the friction between the device (100) and the exhaust gas (117) flowing within the device (100). The acoustic waves (116) are substantially eliminated within the device (100) such that the noise from the exhaust system (200) is significantly reduced.
[037] In an embodiment, the device (100) may include a glass wool within the corrugated structure (108) to improve the noise reduction from the exhaust system (200).

[038] The device (100) may be manufactured of a metallic material which is reliable and capable to withstand high temperature of the exhaust gas (117). In an embodiment, the device (100) may be manufactured of stainless steel and its alloys.
[039] In an embodiment, the maximum diameter (D), the minor diameter (d) and the pitch of the corrugated structure (108) may be varied based on the magnitude of the noise reduction required and capacity of the engine (61).
[040] The device (100) of the present disclosure may be installed within any exhaust system (200) for reducing the noise emanating from the muffler (206) of the vehicle exhaust system (200).
[041] The device (100) of the present disclosure eliminates the need of a pre-silencer, as significant noise reduction is achieved by the device (100). Further, as compared to the pre-silencer, the device (100) is more compact and is lighter in weight.
[042] The device (100) of the present disclosure reduces back pressure of the exhaust gas (117) upon flowing through the corrugated structure (8) and thereby reduces temperature and pressure of the exhaust gas (117) entering the muffler (206). Therefore, the muffler size can also be reduced.
[043] The device (100) eliminates the necessity of a heatshield which is needed to protect the components surrounding the engine (61) such as a fuel tank, brake linings etc. which are exposed to heat continuously during operation of the vehicle (300).
[044] The device (100) of the present disclosure is simple and compact in construction and enables high noise reduction. Further, the size of the muffler (206) is reduced as the substantial noise reduction occurs within the device (100) itself. Advantageously, this reduces overall weight of the exhaust system (200) which also saves cost and increases efficiency of the engine (61).
[045] In an embodiment, the device (100) of the present disclosure enhances Noise, vibration, and harshness parameter of the vehicle (300), thereby keeps occupants within the vehicle (300) from the intense noise of the components, such as the pre-silencer, the muffler (206) and the tail pipe.

[046] It is to be understood that a person of ordinary skill in the art may develop a mechanism or a device of similar configuration without deviating from the scope of the present disclosure. Such modifications and variations may be made without departing from the scope of the present invention. Therefore, it is intended that the present disclosure covers such modifications and variations provided they come within the ambit of the appended claims and their equivalents.
Equivalents:
[047] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
[048] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to

“at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.” While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
Referral Numerals:

Sound attenuation device 100
Exhaust system 200
Vehicle 300
Body 102
Inlet 104
Outlet 106
Corrugated structure 108
Plurality of crests 110
Plurality of troughs 112
Plurality of flow channels 113
Internal passage 114

Acoustic waves 116
Exhaust gas 117
Catalytic converter 201
Central portion 122
First conduit 202
Second conduit 204
First inlet 205
Muffler 206
First outlet 207
Second inlet 209
Second outlet 211
Convex edge 130
Square edge 132
Chassis 60
Engine 61
Frame assembly 62
Transmission assembly 63
A plurality of support members 64
Fastening means 65
A plurality of cross members 66

We claim:
1. A sound attenuation device (100) for a vehicle exhaust system, the sound attenuation
device (100) comprising:
a body (102) defined with a corrugated structure (108);
an internal passage (114) configured to allow flow of an exhaust gas (117) and acoustic waves (116) generated within the vehicle exhaust system (200);
an inlet (104) defined at a first end of the body (102);
an outlet (106) defined at a second end opposite to the first end of the body (102), wherein the inlet (104) is connectable to an exhaust manifold of an engine of the vehicle (300) and the outlet (106) is connectable to a muffler (206) of the vehicle exhaust system (200); and
a plurality of crests (110) and a plurality of troughs (112); wherein the plurality of crests (110) and the plurality of troughs (112) of the corrugated structure (108) are configured to generate interference to the flow of the acoustic waves to attenuate acoustic energy.
2. The sound attenuation device (100) as claimed in claim 1, wherein the plurality of crests (110) and the plurality of troughs (112) are alternately arranged along a length of the body (102) and configured to extend radially outward from a portion of the body (102).
3. The sound attenuation device (100) as claimed in claim 1, wherein each crest (110) of the plurality of crests (110) and each trough (112) of the plurality of troughs (112) is defined with a convex edge (130) opposite to each other along a longitudinal direction of the body (102).
4. The sound attenuation device (100) as claimed in claim 1, wherein the corrugated structure (108) extends spirally along a length of the body (102).
5. The sound attenuation device (100) as claimed in claim 2, wherein the body (102) is defined with a minimum diameter (d) between the portion of the body (102) from which the plurality of crests (110) and the plurality of troughs (112) radially extend in the longitudinal direction of the body (102).

6. The sound attenuation device (100) as claimed in claim 1, wherein the corrugated structure (108) comprises at least one of a square edge (132), a circular edge, a triangular edge, an elliptical edge, a rectangular edge, a polygonal edge and any combination thereof.
7. The sound attenuation device (100) as claimed in claim 2, wherein the plurality of alternating crests (110) and troughs (112) are structured with a pitch ranging between 10 to 100 mm.
8. An exhaust system (200) for a vehicle, the exhaust system (200) comprising:
a muffler (206);
a sound attenuation device (100) disposed in fluid communication between an exhaust manifold of an engine of the vehicle (300) and the muffler (206), the sound attenuation device (100) comprising:
a body (102) defined with a corrugated structure (108);
an internal passage (114) configured to allow flow of an exhaust gas (117) and acoustic waves (116) generated within the vehicle exhaust system (200);
an inlet (104) defined at a first end of the body (102);
an outlet (106) defined at a second end opposite to the first end of the body (102), wherein the inlet (104) is to be connected to the exhaust manifold and the outlet (106) is connected to the muffler (206) of the vehicle exhaust system (200); and
a plurality of crests (110) and a plurality of troughs (112); wherein the plurality of crests (110) and the plurality of troughs (112) of the corrugated structure (108) are configured to generate interference to the flow of the acoustic waves (116) to attenuate acoustic energy before transfer of the exhaust gas (117) to the muffler (206) through the second conduit (204).
9. The exhaust system (200) as claimed in claim 8, wherein the corrugated structure (108) extends spirally along a length of the body (102).
10. The exhaust system (200) as claimed in claim 8, wherein the corrugated structure (108) comprises at least one of a square edge (132), a circular edge, and a rectangular edge.

11. A vehicle comprising: an engine (61);
an exhaust manifold connected to the engine (61); a muffler (206);
a sound attenuation device (100) disposed in fluid communication between the exhaust manifold and the muffler (206), the sound attenuation device (100) comprising: a body (102) defined with a corrugated structure (108);
an internal passage (114) configured to allow flow of an exhaust gas (117) and acoustic waves (116) generated within the vehicle exhaust system (200);
an inlet (104) defined at a first end of the body (102); an outlet (106) defined at a second end opposite to the first end of the body (102), wherein the inlet (104) is connected to the exhaust manifold and the outlet (106) is connected to the muffler (206); and
a plurality of crests (110) and a plurality of troughs (112), wherein the plurality of crests (110) and the plurality of troughs (112) of the corrugated structure (108) are configured to generate interference to the flow of the acoustic waves (116) to attenuate acoustic energy before transfer of the exhaust gas (117) to the muffler (206).