Claims:We claim,
1. An exhaust system 10 comprising:
at least one pre-muffler assembly 20 comprising a housing 22 and an exhaust conduit arrangement 24; and
at least one rear muffler assembly 100 comprising,
a housing 102 defining a first end wall 102a and a second end wall 102b;
at least one exhaust inlet conduit 104 adapted to be provided in fluid communication with said housing 102 and said exhaust conduit arrangement 24 of said pre-muffler assembly 20;
a plurality of baffles (103F and 103S) adapted to be disposed inside said housing 102;
at least one exhaust intermediate conduit 106 adapted to be provided in fluid communication with said housing 102; and
at least one exhaust outlet conduit 108 adapted to be provided in fluid communication with said housing 102.

2. The exhaust system 10 as claimed in claim 1, wherein said exhaust conduit arrangement 24 comprises,
an exhaust inlet conduit 24A adapted to be provided in fluid communication with an engine;
an exhaust intermediate conduit 24B adapted to be connected to said exhaust inlet conduit 24A, where said exhaust intermediate conduit 24B defines a plurality of perforations 24Bp adapted to vent exhaust gases to at least one chamber in said housing 22; and
an exhaust outlet conduit 24C adapted to be connected to said exhaust intermediate conduit 24B.

3. The exhaust system 10 as claimed in claim 2, wherein the closest frequency (103 Hz) mode position to the cabin acoustic mode (90 Hz) is chosen as location of said pre-muffler assembly 20.

4. The exhaust system 10 as claimed in claim 3, wherein said plurality of baffles (103F and 103S) of said rear muffler assembly 100 includes,
a first baffle 103F; and
a second baffle 103S defining a plurality of perforations,
wherein
said first baffle 103F and said second baffle 103S are parallel and spaced away from each other.

5. The exhaust system 10 as claimed in claim 4, wherein said first baffle 103F and the first wall 102a of said housing 102 of said rear muffler assembly 100 defines a first chamber 102f in said housing 102;
said first baffle 103F and said second baffle 103S defines an intermediate chamber 102i in said housing 102; and
said second baffle 103S and the second wall 102b of said housing 102 defines a second chamber 102s in said housing 102.

6. The exhaust system 10 as claimed in claim 5, wherein said exhaust inlet conduit 104 defines at least one inlet 104i adapted to facilitate entry of exhaust gases into said exhaust inlet conduit 104 and at least one outlet 104p adapted to facilitate exit of exhaust gases from said exhaust inlet conduit 104 to the intermediate chamber 102i in said housing 102;
said exhaust intermediate conduit 106 defines at least one inlet 106i adapted to facilitate entry of exhaust gases from the intermediate chamber 102i to said exhaust intermediate conduit 106 and at least one outlet 106p adapted to facilitate exit of exhaust gases from said exhaust intermediate conduit 106 to the first chamber 102f in said housing 102; and
said exhaust outlet conduit 108 defines at least one inlet 108i adapted to facilitate entry of exhaust gases from the intermediate chamber 102i to said exhaust outlet conduit 108 and at least one outlet 108p adapted to facilitate exit of exhaust gases from said exhaust outlet conduit 108.

7. The exhaust system 10 as claimed in claim 6, wherein at least a portion of at least one of said exhaust inlet conduit 104, said exhaust intermediate conduit 106 and said exhaust outlet conduit 108 are spaced away from each other.

8. The exhaust system 10 as claimed in claim 7, wherein said exhaust inlet conduit 104 is not provided with perforations;
the first chamber 102f in said housing 102 of said rear muffler assembly 100 facilitates better acoustic transmission loss for lower range of frequency (70 to 90 Hz).

9. The exhaust system 10 as claimed in claim 8 comprises at least one noise dampening means adapted to be disposed inside the second chamber 102s in said housing 102 to dampen the noise of the exhaust gases received inside said housing 102.

10. A muffler assembly 100 comprising:
a housing 102 defining a first end wall 102a and a second end wall 102b;
a plurality of baffles (103F and 103S) adapted to be disposed inside said housing 102, where said plurality of baffles (103F and 103S) comprises a first baffle 103F and a second baffle 103S ;
at least one exhaust inlet conduit 104 adapted to be provided in fluid communication with an engine and said housing 102;
at least one exhaust intermediate conduit 106 adapted to be supported by said first baffle 103F and provided in fluid communication with said housing 102; and
at least one exhaust outlet conduit 108 adapted to be provided in fluid communication with said housing 102.

11. The muffler assembly 100 as claimed in claim 10, wherein the first end wall 102a of said housing 102 and said first baffle 103F defines a first chamber 102f in said housing 102;
said first baffle 103F and said second baffle 103S defines an intermediate chamber 102i in said housing 102; and
said second baffle 103S and the second end wall 102s of said housing 102 defines a second chamber 102s in said housing 102.

12. The muffler assembly 100 as claimed in claim 12, wherein said exhaust inlet conduit 104 defines at least one inlet 104i adapted to facilitate entry of exhaust gases into said exhaust inlet conduit 104 and at least one outlet 104p adapted to facilitate exit of exhaust gases from said exhaust inlet conduit 104 to the intermediate chamber 102i in said housing 102;
said exhaust intermediate conduit 106 defines at least one inlet 106i adapted to facilitate entry of exhaust gases from the intermediate chamber 102i to said exhaust intermediate conduit 106 and at least one outlet 106p adapted to facilitate exit of exhaust gases from said exhaust intermediate conduit 106 to the first chamber 102f in said housing 102; and
said exhaust outlet conduit 108 defines at least one inlet 108i adapted to facilitate entry of exhaust gases from the intermediate chamber 102i to said exhaust outlet conduit 108 and at least one outlet 108p adapted to facilitate exit of exhaust gases from said exhaust outlet conduit 108.

13. The muffler assembly 100 as claimed in claim 12, wherein at least a portion of at least one of said exhaust inlet conduit 104, said exhaust intermediate conduit 106 and said exhaust outlet conduit 108 are spaced away from each other.

14. The muffler assembly 100 as claimed in claim 13, wherein said exhaust inlet conduit 104 is not provided with perforations;
the first chamber 102f in said housing 102 of said rear muffler assembly 100 facilitates better acoustic transmission loss for lower range of frequency (70 to 90 Hz).

15. The muffler assembly 100 as claimed in claim 14 comprises at least one noise dampening means adapted to be disposed inside the second chamber 102s in said housing 102 to dampen the noise of the exhaust gases received inside said housing 102.
, Description:TECHNICAL FIELD
[001] The embodiments herein relate to an exhaust system for a vehicle.
BACKGROUND
[002] Generally, an exhaust system in a vehicle is used to emit the exhaust gases from an engine to the atmosphere in a controlled manner. A muffler is a device which is used for decreasing the amount of noise emitted by the exhaust of an engine. A conventional exhaust system (not shown) includes an exhaust manifold (not shown), an exhaust down pipe (not shown), a catalytic converter (not shown), a resonator (not shown), a single muffler assembly M (as shown in fig. 1) and a tailpipe (not shown). The muffler assembly M includes a housing H, an inlet pipe I, a plurality of baffles B and an outlet pipe P. The inlet pipe I defines a plurality of perforations R adapted to vent the exhaust gases to the housing H. The muffler assembly M is subjected to high back pressure which in turn decreases the efficiency of the engine. Further, the muffler assembly M is less efficient in dampening the noise of the exhaust from the engine particularly for the lower frequency ranging from 70 to 90Hz thereby leading to reduced acoustic transmission loss. Providing an exhaust system with better NVH (noise, vibrations and harshness) characteristics is difficult and is one of the challenges posed to the original equipment manufacturers (OEM).
[003] Therefore, there exists a need for an exhaust system for a vehicle, which obviates the aforementioned drawbacks. Further, there exists a need for a muffler assembly, which obviates the aforementioned drawbacks.

OBJECTS
[004] The principal object of an embodiment of this invention is to provide an exhaust system for a vehicle, which has better NVH characteristics and reduced backpressure thereof.
[005] Another object of an embodiment of this invention is to provide a rear exhaust muffler assembly for a vehicle, which has better NVH characteristics and better acoustic transmission loss.
[006] Another object of an embodiment of this invention is to provide a pre-muffler assembly for a vehicle, which reduces the noise generated by the exhaust from an engine and assist in achieving higher acoustic transmission loss in high frequency.
[007] Another object of an embodiment of this invention is to provide an exhaust system for a vehicle, which is optimized for various frequency ranges thereby increasing the acoustic transmission loss in respective frequency range.
[008] Another object of an embodiment of this invention is to provide an exhaust system for a vehicle, which achieves reduced sound pressure levels (reduce boom feeling) in an occupant compartment of the vehicle by reducing back pressure and to achieve higher acoustic transmission loss.
[009] Yet, another object of an embodiment of this invention is to provide a rear exhaust muffler assembly for a vehicle, which eliminates the need for providing perforations in an exhaust inlet conduit.
[0010] A further object of an embodiment of this invention is to provide an exhaust system for a vehicle, which assists in achieving better engine performance parameters such as lesser fuel consumption and lesser emission levels.
[0011] 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
[0012] 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:
[0013] Fig. 1 depicts a transparent perspective view of a conventional muffler assembly;
[0014] Fig. 2 depicts a perspective view of an exhaust system for a vehicle, according to an embodiment of the invention as disclosed herein;
[0015] Fig. 3 depicts a transparent front view of a pre-muffler assembly, according to an embodiment of the invention as disclosed herein;
[0016] Fig. 4 depicts a transparent front view of a rear muffler assembly, according to an embodiment of the invention as disclosed herein;
[0017] Fig. 5 depicts a graph plot between acoustic transmission loss (dB) and frequency (Hz) comparison between the conventional muffler assembly and the pre-muffler assembly, according to an embodiment of the invention as disclosed herein; and
[0018] Fig. 6 depicts a graph plot between acoustic transmission loss and frequency comparison between the conventional muffler assembly and the rear muffler assembly, according to an embodiment of the invention as disclosed herein.
DETAILED DESCRIPTION
[0019] 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.
[0020] The embodiments herein achieve an exhaust system for a vehicle, which has better NVH characteristics and reduced backpressure thereof. Further, embodiments herein achieve a rear muffler assembly for a vehicle. Referring now to the drawings, and more particularly to Fig. 2 through 6, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0021] Fig. 2 depicts a perspective view of an exhaust system 10 for a vehicle, according to an embodiment of the invention as disclosed herein. In an embodiment, the exhaust system 10 includes at least one pre-muffler assembly 20, a plurality of rear muffler assemblies 100 and may include other standard components as present in a standard vehicle exhaust system.
[0022] Fig. 3 depicts a transparent front view of a pre-muffler assembly 20, according to an embodiment of the invention as disclosed herein. The pre-muffler assembly 20 is used to reduce the noise of the exhaust received from an engine (not shown). In an embodiment, the pre-muffler assembly 20 includes a housing 22 and an exhaust conduit arrangement 24. The housing 22 defines a chamber (not shown) adapted to receive exhaust gases from an exhaust intermediate conduit 24B of the exhaust conduit arrangement 24. The housing 22 defines a first end wall 22a and a second end wall 22b opposite to the first end wall 22a. In an embodiment, the exhaust conduit arrangement 24 includes at least one exhaust inlet conduit 24A, at least one exhaust intermediate conduit 24B and at least one exhaust outlet conduit 24C. The exhaust conduit arrangement 24 is also called as exhaust duct arrangement. The exhaust inlet conduit 24A is supported by the first end wall 22a of the housing 22. A portion of the exhaust inlet conduit 24A is disposed external to the housing 22 and another portion of the exhaust inlet conduit 24A is received inside the housing 22. The exhaust inlet conduit 24A defines at least one inlet 24Ai and at least one outlet (not shown). The inlet 24Ai of the exhaust inlet conduit 24A is used to facilitate entry of exhaust gases into the exhaust inlet conduit 24A. The outlet (not shown) of the exhaust inlet conduit 24A is used to facilitate exit of exhaust gases from the exhaust inlet conduit 24A to the exhaust intermediate conduit 24B. The exhaust inlet conduit 24A is also called as exhaust inlet duct. The exhaust intermediate conduit 24B is disposed inside the housing 22 and connected between corresponding ends of the exhaust inlet conduit 24A and the exhaust outlet conduit 24C. The exhaust intermediate conduit 24B defines a plurality of perforations 24Bp adapted to vent the exhaust gases to the chamber (not shown) of the housing 22. The exhaust intermediate conduit 24B is also called as exhaust intermediate duct. The exhaust outlet conduit 24C is opposite to the exhaust inlet conduit 24A. The exhaust outlet conduit 24C is supported by the second end wall 22b of the housing 22. A portion of the exhaust outlet conduit 24C is disposed external to the housing 22 and another portion of the exhaust outlet conduit 24C is received inside the housing 22. The exhaust outlet conduit 24C defines at least one inlet (not shown) and at least one outlet 24Cp. The inlet of the exhaust outlet conduit 24C is used to facilitate entry of exhaust gases from the exhaust intermediate conduit 24B to the exhaust outlet conduit 24C. The outlet (not shown) of the exhaust outlet conduit 24C is used to facilitate exit of exhaust gases from the exhaust outlet conduit 24C. The exhaust outlet conduit 24C is also called as exhaust outlet duct. The closest frequency (103 Hz) mode position to the cabin acoustic mode (90 Hz) is chosen as location of pre-muffler assembly 20. It is also within the scope of the invention to select the location of the pre-muffler assembly 20 based on any other frequency mode corresponding to the cabin acoustic mode. The volume of the housing 22 of the pre-muffler assembly 20 is optimized to have higher acoustic transmission loss in high frequency region (as shown in fig. 5). The volume of the housing 22 of the pre-muffler assembly is 5 liters. It is also within the scope of the invention to provide the housing 22 of the pre-muffler assembly 20 in any other volumes. The NVH performance of the pre-muffler assembly 20 and rear muffler assembly 100 results in at least 5 dB (A) reduction in sound pressure levels compared to base configuration. The chamber of the housing 22 of the pre-muffler assembly 20 is tuned to have high acoustic transmission loss in high frequency region. It is also within the scope of the invention to provide any other noise dampening means inside the housing 22 of the pre-muffler assembly 20.
[0023] Fig. 4 depicts a transparent front view of a rear muffler assembly 100, according to an embodiment of the invention as disclosed herein. In an embodiment, each rear muffler assembly 100 (hereinafter called as muffler assembly 100) includes a housing 102, a plurality of baffles (103F and 103S), an exhaust inlet conduit 104, at least one exhaust intermediate conduit 106, an exhaust outlet conduit 108, at least one noise dampening means (not shown) and may include other standard components as present in a standard muffler assembly. The housing 102 is used to support the exhaust inlet conduit 104, the exhaust outlet conduit 108 and the plurality of baffles (103F and 103S). The housing 102 defines a first end wall 102a and a second end wall 102b opposite to the first end wall 102a. The plurality of baffles (103F and 103S) is disposed inside the housing 102. The plurality of baffles (103F and 103S) includes a first baffle 103F and a second baffle 103S. The first baffle 103F and the first end wall 102a of the housing 102 define a first chamber 102f in the housing 102. The first baffle 103F and the second baffle 103S define an intermediate chamber 102i in the housing 102. The second baffle 103S and the second end wall 102b of the housing 102 defines a second chamber 102s in the housing 102, where the second chamber 102s is opposite to the first chamber 102f in the housing 102. The first baffle 103F is used to separate the first chamber 102f and the intermediate chamber 102i in the housing 102. The first baffle 103F supports the exhaust inlet conduit 104, the exhaust intermediate conduit 106 and the exhaust outlet conduit 108. The first baffle 103F is a solid baffle. It is within the scope of the invention to provide the first baffle 103F in any other configuration. The first baffle 103F and the second baffle 103S are parallel and spaced away from each other. The second baffle 103S defines a plurality of perforations (not shown) adapted to allow the exhaust gases to flow to the second chamber 102s in the housing 102. The second baffle 103S supports the exhaust outlet conduit 108. The exhaust inlet conduit 104 is provided in fluid communication with the exhaust conduit arrangement 24 of the pre-muffler assembly 20. A portion of the exhaust inlet conduit 104 is disposed external to the first end wall 102a of the housing 102 and another portion of the exhaust inlet conduit 104 is received inside the housing 102. The exhaust inlet conduit 104 defines at least one inlet 104i and at least one outlet 104p. The inlet 104i of the exhaust inlet conduit 104 is used to facilitate entry of exhaust gases from the pre-muffler assembly 20 to the exhaust inlet conduit 104 of the rear muffler assembly 100. The outlet 104p of the exhaust inlet conduit 104 is used to facilitate exit of exhaust gases from the exhaust inlet conduit 104 to the intermediate chamber 102i in the housing 102. The exhaust inlet conduit 104 is also called as exhaust inlet duct. The exhaust intermediate conduit 106 defines at least one inlet 106i and at least one outlet 106p. The inlet 106i of the exhaust intermediate conduit 106 is adapted to facilitate entry of exhaust gases from the intermediate chamber 102i to the exhaust intermediate conduit 106. The outlet 106p of the exhaust intermediate conduit 106 is adapted to facilitate exit of exhaust gases from the exhaust intermediate conduit 106 to the first chamber 102f in the housing 102. The exhaust intermediate conduit 106 is also called as exhaust intermediate duct. The exhaust outlet conduit 108 defines at least one inlet 108i and at least one outlet 108p. The inlet 108i of the exhaust outlet conduit 108 is adapted to facilitate entry of exhaust gases from the intermediate chamber 102i to the exhaust outlet conduit 108. The outlet 108p of the exhaust outlet conduit 108 is adapted to facilitate exit of exhaust gases from the exhaust outlet conduit 108. The exhaust outlet conduit 108 is also called as exhaust outlet duct. At least a portion of the exhaust inlet conduit 104, the exhaust intermediate conduit 106 and the exhaust outlet conduit 108 are spaced away from each other. The noise dampening means (not shown) is adapted to be disposed inside the second chamber 102s in the housing 102. The noise dampening means is adapted to dampen the noise of the exhaust received inside the housing 102. The noise dampening means is at least a glass wool. It is also within the scope of the invention to provide any other noise dampening means to dampen the noise of the exhaust received inside the housing 102. In an embodiment, the muffler assembly 100 is an elliptical muffler. It is also within the scope of the invention to provide the muffler assembly 100 in any other type and configuration without otherwise deterring the intended function of the muffler assembly 100 as can be deduced from the description and corresponding drawings. The volume of the housing 102 of the muffler assembly 100 is 9.8 liters. It is also within the scope of the invention to provide the housing 102 in any other volumes. The volume of the first chamber 102f, the intermediate chamber 102i and the second chamber 102s in the housing 102 of the muffler assembly 100 is optimized to tune a band of frequency. The volume of the first chamber 102f in the housing 102 is 4.7 liters. It is also within the scope of the invention to provide the first chamber 102f in the housing 102 in any other volumes. The volume of the intermediate chamber 102i in the housing 102 is 4.2 liters. It is also within the scope of the invention to provide the intermediate chamber 102i in the housing 102 in any other volumes. The volume of the second chamber 102s in the housing 102 is 0.9 liters. It is also within the scope of the invention to provide the second chamber 102s in the housing 102 in any other volumes.
[0024] Fig. 5 depicts a graph plot between acoustic transmission loss (dB) and frequency (Hz) comparison between the conventional muffler assembly and the pre-muffler assembly 20, according to an embodiment of the invention as disclosed herein. A CAE (computer aided engineering) test was conducted between acoustic transmission loss (dB) and frequency (Hz) comparison between the conventional muffler assembly and the pre-muffler assembly 20. The curve A in the graph represents the pre-muffler assembly 20. The curve B in the graph represents the conventional muffler assembly. As can be deduced from the graph, it is clearly evident that in the high frequency region, the acoustic transmission loss (dB) of the curve A is higher than the acoustic transmission loss (dB) of the curve B.
[0025] Fig. 6 depicts a graph plot between transmission loss and frequency comparison between the conventional muffler assembly and the rear muffler assembly 100, according to an embodiment of the invention as disclosed herein. A CAE (computer aided engineering) test was conducted between acoustic transmission loss (dB) and frequency (Hz) comparison between the conventional muffler assembly and the muffler assembly 100. The curve A in the graph represents the muffler assembly 100. The curve B in the graph represents the conventional muffler assembly. As can be deduced from the graph, it is clearly evident that in the low frequency ranging between 70 to 90 Hz, the acoustic transmission loss (dB) of the curve A is higher than the acoustic transmission loss (dB) of the curve B.
[0026] Therefore, a muffler assembly 100 for a vehicle and an exhaust system 10 thereof is provided.
[0027] 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.