DESC:CROSS REFERENCE TO RELATED APPLICATION
This application is based on and derives the benefit of Indian Provisional Application 202041021856 filed on 25/05/2020, the contents of which are incorporated herein by reference.

TECHNICAL FIELD
[001] The embodiments herein generally relate to acoustic attenuation device and more particularly, to a modular acoustic attenuation device and a method for attenuating noise in an air intake line of internal combustion engine(s).

BACKGROUND
[002] Engine intake systems may generate noises which may be transmitted through various components to a vehicle cabin. The vehicle operator and/or passengers may find this noise displeasing. Consequently, customer satisfaction may be decreased. For example, a turbocharger compressor may generate noises during operation, which may be transmitted to the vehicle cabin. Other intake system components, such as a throttle, may also generate noises which further decreases the customer satisfaction. Specifically, the noises may resonate through various intake conduits and be transferred through various medium to the vehicle cabin.
[003] In order to attenuate these noises, sound absorbers or acoustic attenuators, are used in internal combustion engines. For example, sound absorbers or acoustic attenuators may be used in the fresh air tract of the internal combustion engine, in order to lessen the sound produced by a turbocharger in the engine utilizing such turbocharger and to lessen the sound dispersed in the fresh air tract.
[004] One of the methodsto reduce the intake noise of the internal combustion engine is to use a Helmholtz resonator on an intake air pipe configured to communicate intake air to the internal combustion engine. The intake air pipe is typically disposed upstream from an intake manifold and is configured to communicate intake air to the intake manifold of the internal combustion engine. The Helmholtz resonator includes a resonance volume or chamber having a small opening, typically referred to as a neck. The neck is operable to enable communication between the resonance chamber and the intake air pipe. Sound waves generated by components within the internal combustion engine travel along the intake air pipe where their acoustic pressure impinges on the neck and excites a mass of air within the neck. The acoustic pressure within the resonance chamber reacts against the air mass within the neck and produces an out-of-phase acoustic pressure at the intake air pipe to cause cancellation of intake noise at the resonant frequency. In this way, some of the engine noise is eliminated as the out-of-phase acoustic pressures in the intake air pipe cancel each other.
[005] When two different engines or variants of same engine are used on the vehicle, the nature of noise source changes. For example, a turbocharged diesel engine and a turbocharged gasoline engine will have different performance curves and different noise characteristics. Hence, in such cases, the resonator may have to be re-adjusted or re-tuned according to the type of engine in order to reduce noise to an acceptable level. The re-adjustment or re-tuning of the resonator is difficult and is one of the challenges posed to the original equipment manufacturers (OEM’s). Further, the re-adjustment or re-tuning of the resonator is a time-consuming process and conventional designs require significant investments for developing completely a new resonator.
[006] Therefore, there exists a need for a modular acoustic attenuation device and a method for attenuating noise in an air intake line of an internal combustion engine(s), which obviates the aforementioned drawbacks.

OBJECTS
[007] The principal object of an embodiment herein is to provide a modular acoustic attenuation device for attenuating noise in an air intake line of an internal combustion engine.
[008] Another object of an embodiment herein is to provide amodular acoustic attenuation device which may be fabricated in a predetermined shape and sizecorrespondingly to be used in conjunction with the air intake line ofany of two different forced air induction engines (turbocharged engine) or forced air induction engines provided in different vehicle package environments or variants of forced air induction engine with different performance level.
[009] Another object of an embodiment herein is to provide a method of attenuating air intake noise of any of two different forced air induction engines or forced air induction engines provided in different vehicle package environments or variants of forced air induction engine with different performance level.
[0010] Another object of an embodiment herein is to provide a modularacoustic attenuation device, which is inexpensive and easy to manufacture.
[0011] Another object of an embodiment herein is to provide a modular acoustic attenuation device, which can be adopted in anair intake line, either on suction side (compressor inlet) or high-pressure side (compressor outlet) of the air intake system of a turbocharged engine.
[0012] These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF DRAWINGS
[0013] The embodiments of the invention are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0014] Fig. 1 depicts a cross-sectional view of a modular acoustic attenuation device, according to embodiments as disclosed herein;
[0015] Fig. 2a and fig. 2b depict exploded views of the modular acoustic attenuation device, according to embodiments as disclosed herein;
[0016] Fig. 3a depicts a perspective view of a conduit of the modular acoustic attenuation device, according to embodiments as disclosed herein;
[0017] Fig. 3b depicts a perspective view of a conduit of the modular acoustic attenuation device, according to anotherembodiments as disclosed herein;
[0018] Fig. 4a depicts a cross-sectional view of the modular acoustic attenuation device, where an outlet casing is oriented at a first position with respect to an inlet casing of the modular acoustic attenuation device, according to embodiments as disclosed herein;
[0019] Fig. 4b depicts another cross-sectional view of the acoustic attenuation device, where theoutlet casing is oriented at a second position with respect to the inlet casing of the modular acoustic attenuation device, according to anotherembodiments as disclosed herein;
[0020] Fig. 5 depict perspective views of the modular acoustic attenuation deviceinstalled in two different engines in a vehicle having different packaging environments, according to another embodiments as disclosed herein;
[0021] Fig. 6 depict perspective views and corresponding cross-sectional views of the modular acoustic attenuation deviceinstalled for four different engines and packaging environments, according to another embodiments as disclosed herein;
[0022] Fig. 7a depicts a graph plot of transmission loss characteristics of the modular acoustic attenuation device having conduit with three resonating chambers, according to embodiments as disclosed herein;
[0023] Fig. 7b depicts a graph plot of transmission loss characteristics of the modular acoustic attenuation device having conduit with six resonating chambers, according to another embodiment as disclosed herein; and
[0024] Fig. 8 depicts a flowchart indicating a method forattenuating noise inair intake line of internal combustion engine, according to embodiments as disclosed herein.

DETAILED DESCRIPTION
[0025] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0026] The embodiments herein achieve a modular acousticattenuation device forattenuating noise in air intake line of aninternal combustion engine. Further, the embodiments herein achieve the modular acoustic attenuation device which may be fabricated in a predetermined shape and sizecorrespondingly to be used in conjunction with the air intake line ofany of two different forced air induction engines (turbocharged engine) or forced air induction engines provided in different vehicle package environments or variants of forced air induction engine with different performance level. Furthermore, the embodiments herein achieve the method of attenuating air intake noise of any of two different forced air induction engines or forced air induction engines provided in different vehicle package environments or variants of forced air induction engine with different performance level. Additionally, the embodiments herein achieve the modularacoustic attenuation device, which is inexpensive and easy to manufacture. Moreover, the embodiments herein achieve the modular acoustic attenuation device, which can be adopted in anair intake line, either on suction side (compressor inlet) or high-pressure side (compressor outlet) of the air intake system of a turbocharged engine. Referring now to the drawings, and more particularly to Figs. 1 through 8, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0027] Fig. 1 depicts a cross-sectional view of a modular acoustic attenuation device (100), according to embodiments as disclosed herein. Fig. 2a andFig. 2b depict exploded views of the modular acoustic attenuation device (100), according to embodiments as disclosed herein. In an embodiment, the modular acoustic attenuation device (100) is adapted to attenuate air intake noise ofone of two different engines or variants of same engine with different performance curves or engines in different vehicle package environments.In an embodiment, the modular acoustic attenuation device (100) includes at least one conduit (102), a housing (104) defined by joining an inlet casing (108) and an outlet casing (110) and at least one baffle (106) integrated with the conduit (102). For the purpose of this description and ease of understanding, the modular acoustic attenuation device (100) is explained herein below with reference to be provided in low pressure side of an air intake system of a forced air induction engine such as a turbocharged engine. However, it is also within the scope of the invention to provide the modular acoustic attenuation device (100) in a lower pressure side or a high pressure side or any other air inlet line of the turbocharged engine or a supercharged engine or a twin charged engine or any other type of engine or any forced air induction applicationswithout otherwise deterring the intended function of the modular acoustic attenuation device(100) as can be deduced from the description and corresponding drawings.
[0028] The housing (104) is fabricated by affixing the inlet casing (108) to the outlet casing (110). The housing (104) is adapted to concentrically enclose the conduit (102) in a spaced relation. The inlet casing (108) is adapted to facilitate entry of air being drawn in by the engine or compressor. Similarly, the outlet casing (110) is adapted to facilitate exit of air being drawn in by the engine or compressor. The inlet casing (108) includes a tubular portion (108t) and a flange portion (108f) extending transversely from the tubular portion (108t). The tubular portion (108t) includes a predetermined diameter and predetermined length. The flange portion (108f) includes a predetermined thickness. Further, the outlet casing (110) includes a stepped tubular portion (110s1) adapted to be affixed with the flange portion (108f) of the inlet casing (108) and a second tubular portion (110s2) extending from the stepped tubular portion (110s1). The second tubular portion (110s2) includes a diameter which is less than the diameter of said first tubular portion (110s1). The stepped portion (110s1) and the second tubular portion (110s2) have predetermined lengths and varying predetermined diameters spanning along said lengths. In an embodiment, the outlet casing (110) is affixed to the inlet casing (108) by one of vibration welding, hot plate welding and spin welding.
[0029] Fig. 3a depicts a perspective view of a conduit (102) of the modular acoustic attenuation device (100), according to embodiments as disclosed herein. The conduit (102) is adapted to provide the inlet casing (108) in fluid communication with the outlet casing (110) of the modular acoustic attenuation device (100). The conduit (102) includes a wall (102w), an inlet (102i) and an outlet (102o). The air in the modular acoustic attenuation device (100) is drawn by the engine (not shown). The conduit (102) includes the plurality of apertures (102a) or slits (not shown), where size, diameter and number of the apertures (102a) or slits (not shown) are predefined in accordance to vehicle type and requirement. In an embodiment, the predetermined diameter of each aperture (102a) is at least one of varied and not varied along a direction of a fluid flow through the conduit (102). In another embodiment, the conduit (102) includes integrated quarter wave conduits (tubes) (not shown). Further, the conduit (102) includes at least one baffle (106) integrated therewith. In an embodiment, the baffle (106) is substantially orthogonal to an axis (not shown) of the conduit (102). The conduit (102) and the integrated baffle(s) (106) in conjunction with the housing (104) defines a plurality of radially extending resonating chambers (112) (as shown in fig. 1), where each resonating chamber (112) is adapted to attenuate noise of predetermined frequency band. Each chamber (112) provided in communication with the conduit (102) via the plurality of apertures (102a). In an alternate embodiment, the chambers are provided in communication with the conduit (102) via the plurality of slits (not shown) or the quarter wave tubes (not shown). In an embodiment, the conduit (102) is snap fitted to the outlet casing (110). However, it is also within the scope of the invention to connect the conduit (102) to the outlet casing (110) by plastic welding or any other type of temporary joints or permanent joints. The outlet casing (110) along with the conduit (102) is plastic welded to the inlet casing (108). It is also within the scope of the invention to connect the outlet casing (110) to the inlet casing (108) by vibration welding or spin welding or any other type of temporary and permanent joints. In an embodiment, the number of baffles (106) can be varied to define plurality of resonating chambers (112). For example, the number of baffles (106) is 3 (as shown in fig. 3a) and the number of baffles (106) is 6 (as shown in fig. 3b). The number of baffles (106) is variedbased on the type and configuration of engine and requirement of the vehicle. It is also within the scope of the invention to provide any number of baffles (106) to the conduit (102) based on the type and configuration of engine and requirement of the vehicle.
[0030] The conduit (102) having one of the apertures (102a) or slits and the quarter wave conduits (tubes) along with integrated baffles (106), can be configured or altered (tweaked) without any modifications in the inlet casing (108) and the outlet casing (110) of the modular acoustic attenuation device (100) to have specific noise attenuation performance.
[0031] Fig. 4a depicts a cross-sectional view of the modular acoustic attenuation device (100), where the outlet casing (110) is oriented at a first position with respect to the inlet casing (108) of the modular acoustic attenuationdevice (100), according to embodiments as disclosed herein. Fig. 4b depicts another cross-sectional view of the modular acoustic attenuation device (100), where the outlet casing is oriented at a second position with respect to the inlet casing of the modular acoustic attenuation device (100), according to another embodiment as disclosed herein. The inlet casing (108) defines a first axis (not shown) at a central portion of the inlet casing (108) and the outlet casing defines a second axis (not shown) which is defined at a central portion of the outlet casing (110s2). In an embodiment, the first axis of the inlet casing (108) is one of in-line and offset with respect to the second axis of the outlet casing (110s2). Irrespective of conduit variant, the outlet casing (110) can be re-oriented at any angle (i.e. 0º to 360º) with respect to the inlet casing (108) about thefirst axis of the inlet casing (108) which enables the modular acoustic attenuation device (100) adapted to be used in different vehicle package environments.
[0032] The inlet casing (108), the outlet casing (110) and the conduit (102) of the modular resonating device (100) are made of thermoplastics through injection molding process. It is also within the scope of the invention to provide the inlet casing (108), the outlet casing (110) and the conduit (102) to be made of any other material according to the vehicle application and requirement.
[0033] Fig. 5 depicts perspective views of the modular acoustic attenuation device installed in two different engines in a vehicle having different packaging environments, according to anotherembodiments as disclosed herein. Fig. 6 depict perspective views and corresponding cross-sectional views of the modular acoustic attenuation device installed for four different engines and packaging environments, according to another embodiments as disclosed herein. The modular acoustic attenuation device (100) is adapted to be used on two vehicles having different package environments but using same engine by varying the relative orientations of outlet casing (110) with respect to inlet casing (108) for a given conduit (102) tuned to suppress air intake noise and have a smooth fluid flow to the engine of the vehicle. Therefore, using combinations of variations in features of conduit (102) and the relative orientations of outlet casing (110) with respect to the inlet casing (108), the modular resonating device (100) can be adopted for different engines used on different vehicles. In an embodiment, the number of apertures (102a) and corresponding diameter for apertures, number of slits and corresponding aperturefor slits, number of quarter wave conduits (tubes) and correspondinglengths, number and location of baffles (106), can be suitably adjusted to get desired noise attenuation performance thereby enabling the modular acoustic attenuation device (100) suitable for one of two different engines or variants of same engine with different performance curves.
[0034] Fig. 7a depicts a graph plot of transmission loss characteristics of the modular acoustic attenuation device having conduit with three resonating chambers, according to embodiments as disclosed herein. Fig. 7b depicts a graph plot of transmission loss characteristics of the modular acoustic attenuation device having conduit with six resonating chambers, according to another embodiment as disclosed herein. The graphs are plotted for the transmission loss vs broad range of frequency of noise. The graph is plotted to show how two different variants of modular acoustic attenuation device (100) have higher transmission loss in certain predetermined frequency bands to address high air intake noise levels observed in those bands.
[0035] Fig. 8 depicts a flowchart indicating a method (200) forattenuating noise inair intake line of internal combustion engine, according to embodiments as disclosed herein. For the purpose of this description and ease of understanding, the method (200) is explained herein below with reference to attenuating noise of intake air of one of two different forced air induction engines (turbocharged diesel engine or turbocharged gasoline engine) or engines in different vehicle package environments or variants of same engine with different performance level. However, it is also within the scope of this invention to practice/implement the entire steps of the method (200) in the same manner or in a different manner or with omission of at least one step to the method (200) or with any addition of at least one step to the method (200) for attenuating air intake noise of any other type of engines or any other type of vehicleswithout otherwise deterring the intended function of the method (200) as can be deduced from the description and corresponding drawings. In an embodiment, the method (200) includes, receiving a conduit (102) in a housing (104) (at step 202). Further, the method (200) selecting a predetermined number of apertures (102a) on said conduit (102) and predetermined number of baffles (106) to be integrated with said conduit (102) (at step 204). Furthermore, the method (200) includes determining an orientation of an inlet casing (108) relative to an outlet casing (110) defined by said housing (104) (at step 206). Additionally, the method (200) includes defining radially extending chambers (112) of varying volumetric capacity, by joining said housing (104) and said baffle (106) (at step 208).
[0036] Thus, the modular acousticattenuation device (100) and the method (200) facilitates in attenuatingthe noise inthe air intake line of the internal combustion engine.
[0037] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications. Such specific embodiments without departing from the generic concept, and therefore such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
,CLAIMS:We claim,

1. A modular noise attenuating device (100), comprising:
a conduit (102) having a wall (102w), an inlet (102i) and an outlet (102o);
a housing (104) enclosing said conduit (102); and
at least one baffle (106) integrated to said conduit (102) at a predetermined location,
wherein,
said conduit (102) defines a plurality of apertures (102a) in said wall;
said housing (104) and said baffle (106) together defines radially extending chambers (112) of varying volumetric capacity, wherein each chamber (112) is tuned to attenuate noise of predetermined frequency; and
said each chamber provided in communication with said conduit (102) via said plurality of apertures (102a).

2. The modular noise attenuating device (100) as claimed in claim 1, wherein said baffle (106) is substantially orthogonal to an axis of said conduit (102).

3. The modular noise attenuating device (100) as claimed in claim 1, wherein said housing (104) is formed by coupling an inlet casing (or inlet casing) (108) and an outlet casing (or outlet casing) (110), said conduit (102) is at least snap fitted to said outlet casing (110).

4. The modular noise attenuating device (100) as claimed in claim 3, wherein said inlet casing (108) includes a tubular portion (108t) and a flange portion (108f) extending transversely from said tubular portion (108t).

5. The modular noise attenuating device(100) as claimed in claim 3, wherein said outlet casing (110) includes a stepped tubular portion (110s1) adapted to be coupled with said flange portion (108f) of said inlet casing (108) and a second tubular portion (110s2) extending from said stepped tubular portion (110s1), said second tubular portion (110s2) includes a diameter which is less than a diameter of said first tubular portion (110s1), said outlet casing (110) is affixed to said inlet casing (108) by one of plastic welding, vibration welding and spin welding.

6. The modular noise attenuating device (100) as claimed in claim 1, wherein said each aperture(102a) formed in said wall (102w) of said conduit (102) includes a predetermined diameter, said predetermined diameter of each aperture (102a) is at least one of varied and not varied along a direction of fluid flow through said conduit (102).

7. The modular noise attenuating device (100) as claimed in claim 1, wherein said housing (104) is sub-divided into grouped resonance chambers (112) by a plurality of transverse baffles (106), each of said chambers (112) includes varying volumetric capacity which are tuned to attenuate noise of predetermined frequency.

8. The modular noise attenuating device (100) as claimed in claim 1, wherein said inlet casing (108) defines a first axis which is one of in-line and offset with respect to a second axis defined by said outlet casing (110).

9. The modular noise attenuating device (100) as claimed in claim 1, wherein said conduit (102) defines a plurality of slits at predetermined location of said wall (102w), said each resonating chamber (112) is provided in communication with said conduit (102) via said plurality of slits.

10. The modular noise attenuating device (100) as claimed in claim 1, wherein said conduit (102) includes a plurality of quarter wave tubes integrated at predetermined location of said wall (102w), said at least one resonating chamber (112) is provided in communication with said conduit (102) via said plurality of quarter wave tubes.
11. The modular noise attenuating device (100) as claimed in claim 1, wherein said modular acoustic attenuation device (100) is adapted to attenuate air intake noise of one of two different engines, variants of same engine with different performance curves and engines in different vehicle package environments,by correspondingly predefining number and location of said baffles (106), number and diameter of said apertures (102a) on said conduit (102), and an orientation of said inlet casing (108) and said outlet casing (110).

12. A method (200) for attenuating noise in air intake line of internal combustion engine, comprising:
receiving a conduit (102) in a housing (104);
selecting a predetermined number of apertures (102a) on said conduit (102) and predetermined number of baffles (106) to be integrated with said conduit (102);
determining an orientation of an inlet casing (108) relative to an outlet casing (110) defined by said housing (104); and
defining radially extending chambers (112) of varying volumetric capacity, by joining said housing (104) and said baffle (106),
wherein,
each chamber (112) is tuned to attenuates noise of predetermined frequency.