FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION An exhaust system for an automobile
APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Mandal Goutam & Sao Arijit
all Indian national of TATA MOTORS LIMITED
an Indian company having its registered office at
Bombay House, 24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.

An exhaust system for an automobile
Field of invention:
The present invention relates to an automotive vehicle and more particularly the present invention is related to an exhaust system of an automobile having absorption and reaction type muffler for a heavy commercial vehicle.
Background of the invention:
Exhaust muffler is used to attenuate the noise of exhaust gas which is coming out from engine to the desired decibel as per norms for all type of vehicles. Primarily, the desired noise reduction is the essential requirement of all categories of exhaust muffler. Secondly, the shape of muffler has to be such that doesn't affect the packaging or fitment of all other aggregates of vehicles. Thirdly, the design and configuration of said muffler has to be suitable to fit on vehicles easily. Fourthly, the said muffler should be cost-effective. The conventional muffler for high capacity engine are very costly and the noise reduction is not satisfactory to meet the regulation.
An exhaust system for automobiles is developed which addresses the above mentioned disadvantages of the conventional exhaust system, more particularly, the noise reduction.
Object of invention:
The main object of the present invention is to provide an exhaust system for an automobile.
Another object of the present invention is to provide an exhaust system for an automobile which is very compact and useful and cost effective for heavy commercial vehicle.

Yet another object of the present invention is to provide an exhaust system for an automobile which is mixed type i.e. combination of reaction and absorption type silencer.
Statement of invention:
An exhaust system for automobile comprises; a hollow passageway (01), a central baffle (2) provided midway in said hollow passageway (1), a first perforated plate (03) disposed adjacent to said central baffle (2), an inlet pipe (04), an outlet pipe (05), first end cover plate (06 ) and second end cover plate (07) provided on each end of said hollow passageway (1), second perforated plate (08) provided inside and adjacent to said first end cover plate (06), said central baffle (02) divide said hollow passageway (01) into an infer chamber (09) and an outlet chamber (10) of equal length and volume, axis of said inlet pipe (04) and outlet pipe (05) are perpendicular to that of said hollow passageway (01) and are disposed in said inlet chamber (09) and outlet chamber (10) respectively.
The exhaust system , in accordance with this invention, wherein said, hollow passageway (01), central baffle (02), first perforated plate (03), said first end cover plate (06) and second end cover plate (07) and second perforated plate (08) are preferably circular in shape,
The exhaust system, in accordance with this invention, wherein said central baffle (02) is having at least two holes (11a, 11b) with predetermined centre distance between said two holes.
The exhaust system, in accordance with this invention, wherein said central baffle (02) comprises at least two bell mouth circular members (12a, 12b) disposed one through each said holes (11a,l1b) and said bell mouth portion is disposed in said inlet chamber (09).

The exhaust system, in accordance with this invention, wherein said each bell mouth member (12a, 12b) comprises at least two rows of perforation holes with at least 10 holes per row.
The exhaust system, in accordance with this invention, wherein said two bell mouth members (12a, 12b) are rigidly connected to said central baffle (02) and said first perforated plate (03) is disposed in said inlet chamber (09) at predetermined gap from said central baffle (02) and perforations on the bell mouth members (12a, 12b) are arranged in said gap only.
The exhaust system, in accordance with this invention, wherein said inlet pipe (04) comprises plurality of perforations of holes arranged in rows with predetermined pitch and 1st row of perforation from the inlet end is at predetermined distance.
The exhaust system, in accordance with this invention, wherein said inlet pipe (04) end comprises a plate (13) and resilient member (14), said plate (13) is loaded against the said resilient member (14) and disposed concentrically on the bolt assembly (15).
The exhaust system , in accordance with this invention, wherein said resilient member (14) is a spring having the stiffness ranging from 3 to 8 kg/mm, the stiffness of said resilient member (14) is adjusted by tightening or loosing the nut of said bolt assembly (15).
The exhaust system, in accordance with this invention, wherein said plate (13) having a central hole through which said bolt is disposed and said plate (13) can easily move along the bolt of said nut bolt assembly (15).
The exhaust system , in accordance with this invention, wherein right end of the inlet chamber (09) having a first end cover plate (06) and second perforated plate (08) having plurality of perforations which is disposed adjacently inner side, the glass wool is sandwiched in between said plate (06) and perforated plate (08).

The exhaust system, in accordance with this invention, wherein said outlet chamber (10) having said outlet pipe (05) is disposed therein comprising a tapered funnel portion and straight portion, said straight portion comprises plurality of perforation arranged in cross row fashion with predetermined pitch.
The exhaust system , in accordance with this invention, wherein inlet of said outlet pipe (05) having a perforated plate (16) rigidly connected preferably with the help of welding, outer end of said outlet pipe (05) is bend either towards left or right side and end portion is chamfered by 45 degree.
Brief description of invention:
In accordance with the present invention, An exhaust system for automobile comprises; a hollow passageway (01), a central baffle (2) provided midway in said hollow passageway (1), a first perforated plate (03) disposed adjacent to said central baffle (2), an inlet pipe (04), an outlet pipe (05), first end cover plate (06 ) and second end cover plate (07) provided on each end of said hollow passageway (I), second perforated plate (08) provided adjacent to each said end cover plates, said central baffle (02) divide said hollow passageway (01) into an inlet chamber (09) and an outlet chamber (10) of equal length and volume, axis of said inlet pipe (04) and outlet pipe (05) are perpendicular to that of said hollow passageway (01) and are disposed in said inlet chamber (09) and outlet chamber (10) respectively.
Brief description of drawings:
Figure-01 is the isometric view of the silencer in accordance with the present invention.
Figure-02 is a schematic representation of the silencer as viewed from the front of the silencer.
Figure-03 is a schematic representation of the silencer as viewed from the left side of the silencer.

Figure-04 is a schematic representation of the silencer as viewed from the top of the silencer,
Figure-05 is a schematic of perforated plate (03) situated at left side inlet chamber (09).
Figure-06 is a schematic representation of the bell mouth circular members (12a, 12b) as viewed from front and left respectively.
Detailed description of invention:
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same.
In accordance with the present invention, An exhaust system for automobile comprises; a hollow passageway (01), a central baffle (2) provided midway in said hollow passageway (1), a first perforated plate (03) disposed adjacent to said central baffle (2), an inlet pipe (04), an outlet pipe (05), first end cover plate (06 ) and second end cover plate (07) provided on each end of said hollow passageway (1), second perforated plate (08) provided adjacent to inlet end cover plate(06), said central baffle (02) divide said hollow passageway (01) into an inlet chamber (09) and an outlet chamber (10) of equal length and volume, axis of said inlet pipe (04) and outlet pipe (05) are perpendicular to that of said hollow passageway (01) and are disposed in said inlet chamber (09) and outlet chamber (10) respectively.
The said hollow passageway (01), central baffle (02), first perforated plate (03), said first end cover plate (06) and second end cover plate (07) and second perforated plate (08) are preferably circular in shape.
The central baffle (02) is having at least two holes (11a, l1b) with predetermined centre distance between said two holes. The centre distance between said two holes is at least 230 mm preferably.

The said central baffle (02) divide said circular passageway (1) into two chambers; an inlet chamber (09) and an outlet chamber (10). Length and volume of each said chambers are equal.
The first perforated plate (03) is disposed in the said inlet chamber (09) adjacent to said central baffle (02) with predetermined gap between them.
Said central baffle (02) and first perforated plate (03) comprises at least two inline holes (IIa, l1b). The said central baffle (02) and said first perforated plate (03) comprises a bell mouth circular members (12a, 12b) disposed through said inline holes (11a, 1 lb). The said two bell mouth members (12a, 12b) is rigidly connected to said central baffle (02) and said first perforated plate (03) is provided adjacent to said central baffle (02) preferably with the help of welding it to said hollow passageway (01). The said bell mouth circular members (12a, 12b) at the central baffle (02) help generate low back pressure than the simple circular opening and also attenuate more noise.
The predetermined distance or gap between said central baffle (02) and said first perforated plate (03) is 15 mm and the perforation on the said bell mouth fall in the said gap portion only.
Each said bell mouth member (12a, 12b) comprises at least two row of perforation hole with at least 10 holes per row wherein said perforations of said bell mouth members are arranged in the said predetermined gap between central baffle (02) and first perforated plate (03). The said gap between central baffle (02) and first perforated plate (03) is filled with the glass wool.
The said bell mouth member (12a, 12b) comprises a bell mouth portion. The distance of the first row from the bell mouth portion of bell mouth member (12a, 12b) and inter row distance is predetermined.

The said inlet pipe (04) comprises plurality of perforations of holes arranged in plurality of rows with predetermined pitch. The 1st row of perforations from the inlet end is at predetermined distance.
The said inlet pipe end comprises a plate (13) and resilient member (14) arrangement to constitute a spring loaded valve which helps absorb the impact of exhaust gas and facilitates the energy level of the exhaust gas to drop enabling the pressure drop of exhaust gas.
The said plate (13) is loaded against the said resilient member (14) which is disposed concentrically on the nut bolt assembly (15). The said resilient member (14) is a spring having the stiffness ranging from 3 to 8 kg/mm. The stiffness of said resilient member (14) adjusted by tightening or loosing the said nut bolt assembly (15).
The said plate (13) having a central hole through which said bolt is disposed and said plate (13) can easily move along the bolt of said nut bolt assembly (15). At the two end of the bolt there are two nuts, one inside and another one out side of inlet pipe (04) end.
At the right end of the inlet chamber (09), a first end cover plate (06) is provided. A second perforated plate (08) with plurality of perforation hole is disposed in said inlet chamber (09) adjacent to said first end cover plate (06). The glass wool is sandwiched between said first end cover plate (06) and said second perforated plate (08). The thickness of said glass wool sandwiched is predetermined. The density of glass wool is in the range of 115 gram/liter to 135 gram/liter.
At the left end of the inlet chamber (09), a first perforated plate (03) is disposed adjacent to said central baffle (02). The said first perforated plate (03) is having an inline hole corresponding to holes (11a, 11b) of said central baffle (02). The centre distance of the said two holes is predetermined. In the remaining portion of the said first perforated plate (03), there is plurality of perforation of hole.

The gap between the central baffle (02) and said first perforated plate (03) is also predetermined which is 15 mm and said gap is filled with glass wool with density ranging from 115 gram/liter to 135 gram/liter. The two end glass wool lining at the said inlet chamber (09) absorbs high frequency noise.
At the outlet chamber (10), said outlet pipe (05) is disposed. The said outlet pipe (05) comprises tapered funnel portion and straight portion. The straight portion comprises plurality of perforation arranged in cross row fashion with predetermined pitch. At inlet of the said outlet pipe (05) there are one perforated plate (16) rigidly connected preferably with the help of welding.
The outer end of said outlet pipe (05) is bend either towards left or right side and end portion is chamfered by 45 degree. Said outlet pipe (05) facilitates the two way entry of gas. The first entry directions is from inlet end through said perforated plate (16) and another is from the periphery of the outlet pipe through the perforations provided therein. The said two entries are perpendicular with each other and react with each other causing pressure drop as well as noise attenuation.
Impact of the exhaust gas is absorbed by the adjustable plate (13) and resilient member (14) which is spring loaded valve at the end of the inlet pipe (04) by which the energy level of the exhaust gas drops which is the cause of the pressure drop of exhaust gas. The two end glass wool lining at the said inlet chamber (09) absorbs the high frequency noise. The said bell mouth circular members (12a, 12b) provided at the central baffle (02) help generate low back pressure than the simple circular opening and also attenuate more noise. In the tapered perforated outlet pipe (05) there are two inlet directions of exhaust gas; one from inlet end through said perforated plate (16) and another from the periphery of the said outlet pipe (05) through the perforation provided therein.
Present invention suitable for the vehicle with high capacity engine. The silencer is very compact and useful for heavy commercial vehicle. The invented silencer is mixed type i.e. combination of reaction and absorption type silencer.

The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

We Claim:
1. An exhaust system for automobile comprises; a hollow passageway (01), a central baffle (2) provided midway in said hollow passageway (1), a first perforated plate (03) disposed adjacent to said central baffle (2), an inlet pipe (04), an outlet pipe (05), first end cover plate (06 ) and second end cover plate (07) provided on each end of said hollow passageway (1), second perforated plate (08) provided inside and adjacent to said first end cover plate (06), said central baffle (02) divide said hollow passageway (01) into an inlet chamber
(9) and an outlet chamber (10) of equal length and volume, axis of said inlet pipe (04) and outlet pipe (05) are perpendicular to that of said hollow passageway (01) and are disposed in said inlet chamber (09) and outlet chamber
(10) respectively.

2. The exhaust system as claimed in claim 1, wherein said, hollow passageway (01), central baffle (02), first perforated plate (03), said first end cover plate (06) and second end cover plate (07) and second perforated plate (08) are preferably circular in shape.
3. The exhaust system as claimed in claim 1, wherein said central baffle (02) is having at least two holes (11a, 11b) with predetermined centre distance between said two holes.
4. The exhaust system as claimed in claim 1, wherein said central baffle (02) comprises at least two bell mouth circular members (12a, 12b) disposed one through each said holes(l la.11b) and said bell mouth portion is disposed in said inlet chamber (09).
5. The exhaust system as claimed in claim 1, wherein said each bell mouth member (12a, 12b) comprises at least two rows of perforation holes with at least 10 holes per row.

6. The exhaust system as claimed in claim 1, wherein said two bell mouth members (12a, 12b) are rigidly connected to said central baffle (02) and said first perforated plate (03) is disposed in said inlet chamber (09) at predetermined gap from said central baffle (02) and perforations on the bell mouth members (12a, 12b) are arranged in said gap only.
7. The exhaust system as claimed in claim 1, wherein said inlet pipe (04) comprises plurality of perforations of holes arranged in rows with predetermined pitch and 1st row of perforation from the inlet end is at predetermined distance.
8. The exhaust system as claimed in claim 1, wherein said inlet pipe (04) end comprises a plate (13) and resilient member (14), said plate (13) is loaded against the said resilient member (14) and disposed concentrically on the bolt assembly (15).
9. The exhaust system as claimed in claim 1, wherein said resilient member (14) is a spring having the stiffness ranging from 3 to 8 kg/mm, the stiffness of said resilient member (14) is adjusted by tightening or loosing the nut of said bolt assembly (15).
10. The exhaust system as claimed in claim 1, wherein said plate (13) having a central hole through which said bolt is disposed and said plate (13) can easily move along the bolt of said nut bolt assembly (15).
11. The exhaust system as claimed in claim 1, wherein right end of the inlet chamber (09) having a first end cover plate (06) and second perforated plate (08) having plurality of perforations which is disposed adjacently inner side, the glass wool is sandwiched in between said plate (06) and perforated plate (08).

12.The exhaust system as claimed in claim 1, wherein said outlet chamber (10) having said outlet pipe (05) is disposed therein comprising a tapered funnel portion and straight portion, said straight portion comprises plurality of perforation arranged in cross row fashion with predetermined pitch.
13. The exhaust system as claimed in claim 1, wherein inlet of said outlet pipe (05) having a perforated plate (16) rigidly connected preferably with the help of welding, outer end of said outlet pipe (05) is bend either towards left or right side and end portion is chamfered by 45 degree.
14. An exhaust system for automobile as herein described with reference to accompanying drawings.