FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
Cost-effective Vortex flow type exhaust muffler 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
Sanjoy Biswas
Anirban chakraborty
Sanjay Sharma
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 performed.

Field of invention
The present invention is related to Cost-effective Vortex flow type exhaust muffler of vehicles. More particularly it relates to sound attenuating system of exhaust gas of diesel engine of Medium and Heavy Commercial Vehicle.
Background of invention
Exhaust muffler or silencer is required to attenuate the noise of exhaust gas, expelled from engine to the desired decibel (as per standard) for all type of road vehicles. This is the primary requirement of all categories of exhaust muffler used in road vehicles. Secondly, it should not affect the packaging or fitment of all other components of vehicles. Thirdly, it shapes to be such configuration that helps to Fit on vehicles easily & meets the required afford-ability.
Currently, the Exhaust muffler used on Medium and Heavy Commercial Vehicle is not meeting the required ford-ability for all vehicles, especially for difficult terrain applications and its cost is too high and does not provide flexibility of interchangeability.
Object of invention
The main object of the present invention is to obviate the above mentioned drawbacks by developing cost effective Exhaust Muffler for medium and heavy range of Commercial Vehicles.
Another object of the present invention is to increase the noise attenuating level than the existing silencer/muffler.
Yet another object of the present invention is to develop highly flexible type exhaust muffler.
Yet another object of the present invention is to introduce unconventional Vortex Flow principle of fluid flow for reduction of noise, in addition to sound dissipation using absorptive material for this exhaust muffler of Medium and Heavy Commercial Vehicles.

Fifth, object of the present invention is to develop an exhaust muffler which can increase the ford-ability particularly for army vehicles.
Sixth, object of this present invention is to reduce the shell noise of exhaust muffler,
Another object of this invention is to keep provision of introducing the catalytic elements to improve some amount of exhaust emission in parallel to sound attenuation.
Summary of invention
An Exhaust system of any Commercial vehicles (LCV, MCV & HCV) or car (sedan, Hatchback, SUV, and MUV) should have an elbow fitted on engine, exhaust pipes up to the Exhaust Muffler, Exhaust muffler & tail pipe. Exhaust muffler selection (shape, size & performance) is related to Engine size, vehicles' application areas & other aggregates' placement on the vehicle.
The exhaust muffler is a kind of chamber which is used to attenuate the exhaust noise. According to the requirements the chamber of muffler is constructed in various ways. To design an exhaust muffler different types of principles or combination of 2-3 are used for reduction of noise.
The existing muffler is basically a flow reversal type reflective/reactive muffler. In addition to this a glass wool bag is wrapped around the inserted portion outlet pipe for noise absorption in this muffler.
The current invention is basically an improved Exhaust muffler; where mainly vortex flow and sound absorption principle are used for noise reduction. We also used the assy inlet pipe, outer shell, inner shell, out let pipe, baffle, tail pipe etc where lots of design consideration are taken care to make the muffler design flexible, high performing and cost benefiting.

The current muffler's shell arrangement is sandwich type where between the two shells (outer & inner) a ceramic blanket is used to reduce inside noise reduction and heat reduction of outer shell.
Tangential exhaust gas entry and axial exit arrangements are incorporated in current exhaust muffler. Further, a conical perforated tube in the rear half of muffler is fitted. This arrangement helps to create and well support the vortex flow principle. This flow helps to increase the axial velocity of exhaust gases at the cost of its pressure. In addition to noise reduction better scavenging effect is also observed here.
To achieve good absorption effect, high quality (property wise) glass wool bags are used in two places. First one is placed between the front end cover and perforated baffle near the inlet of the Exhaust muffler. Second bag is placed in rear side of muffler between the gap of conical perforated pipe, rear end cover and muffler inner shell.
Further, the outlet pipe is designed in such a way that for clamping of tail pipe it is possible to use rear end cover & outlet pipe both. Also, to resolve the space constraint issues this muffler shell is designed 2-7% lesser in volume by decreasing the shell's length. Due to the combination effect of above two reasons, overall length of muffler is decreasing by considerable amount. These are parts of design flexibility of current muffler.
The Tail pipe used in this muffler can be fitted at any angle of rotation with outlet pipe, using the pipe clamp and fasteners. For fitment of tail pipe Rear end cover also has the provision. Because of axial outlet of muffler the ford-ability is improved compared to existing muffler.
The cost effectiveness of this muffler is also evaluated by ERC's ancillary development department (ADD) of TML. It is predicted by the expert team of ADD that present muffler can be develop with 20-30% lesser cost.

Lastly, the systematic utilization of catalytic elements along with the glass wool bag in the space between the conical perforated tube, rear end cover and muffler inner shell can be improve the exhaust emission quality by marginal amount.
Brief description of drawings
FIG. 1 Shows the Front view of Assy Muffler & side view
FIG. 2 Shows the Top view of Assy Muffler
FIG. 3 Shows the Assy Muffler with tail pipe (ISO view).
FIG. 4 shows sectional view of Assy Muffler with tail pipe.
FIG. 5 shows the schematic view of exhaust gas flow through Assy muffler with tail pipe.
Statement of invention
Accordingly the present invention discloses a cost-effective vortex flow type exhaust
muffler comprising of
a muffler body comprising two layers outer shell (1) and inner shell (2);
at least one ceramic blanket (3) sandwiched inside said outer shell (1) and inner shell (2)
to reduce the inside noise radiation and increase insulation properties;
at least one front end cover (4) and one rear end cover (5) configured to complete the
muffler volume;
at least one conical perforated tube (7) fastened to said rear end cover (5) and said inner
shell (2);
at least one assembly inlet pipe (8) fastened on both the muffler shell tangentially consists
of an inlet pipe (8a) and pipe flange (8b);
at least one perforated baffle (6) fitted near said assembly inlet pipe (8);
at least one glass wool bag 1 (10) is placed between the front end cover (4) and said
perforated baffle plate (6) to absorbs the high frequency noise of pulsating exhaust gas;
at least one glass wool bag 2 (11) is placed between said inner shell (2) and said conical
perforated tube (7) to absorbs the high frequency noise;
at least one outlet pipe (9) configured to be inserted into and fastened with rear end cover
(5); and

at least one tail pipe (12) clamped with the said muffler outlet pipe (9) and rear end cover (5) together with pipe clamping arrangement (13) and (14).
Detailed description of invention
As mentioned, the present muffler is designed taken into account the cost-effectiveness with better performance and to provide maximum flexibility in fitment of same engine volume ranges M & HCV. It has been constructed using the following components -
1) Outer Shell
2) Inner Shell
3) Ceramic Blanket / Cerablanket
4) Front End Cover
5) Rear End Cover
6) Perforated Baffle Plate
7) Conical Perforated Tube
8) Assembly Inlet Pipe

a) Muffler Inlet Pipe.
b) Pipe Flange
9) Muffler Outlet Pipe
10) Glass wool Bag 1.
11) Glass wool bag 2
12) Tail Pipe
13) Pipe Clamp
14) Fasteners (for tail pipe clamping)
The Ceramic Blanket (3) is sandwiched in between the Outer Shell (1) and Inner Shell (2) prevents the outer surface of the muffler from excessive heating and creates a doubling effect for better noise reduction. The Assembly Inlet Pipe (8) is been welded on the muffler shell tangentially such that creating a Vortex Flow of the gases inside the muffler. The glass wool bag 1 (10) packaging at the front end absorbs the high frequency Noise of pulsating exhaust gas, coming out from engine. It is placed between the front

end cover and perforated Baffle plate (6). The Conical perforated Tube (7), guide the Exhaust Gases towards tail pipe (12) gradually increasing the velocity of gases by the converging effect and helps to reduce the back pressure of the gases. In between the inner shell (2) and Conical Perforated Tube (7), Glass wool bag 2 (11) is placed for the same reason i.e. for absorption of high frequency noise. The tail pipe (12) is clamped with the muffler outlet pipe (9) with pipe clamp and related fasteners. This arrangement gives the facility of changing the orientation of Tail Pipe (12) as per the vehicle requirement. To improve the Exhaust emission quality catalytic element can be placed along with glass wool instead of only using the glass wool bag 2 (11). For this we need to do systematic utilization of the space between the conical perforated tube (7), rear end cover (5) and muffler inner shell (2).
Referring to the drawings where the showings are for the purpose of illustrating a preferred embodiment of this invention only.
The muffler body is made of two layers of shell namely Outer Shell (1) and Inner shell
(2) respectively. This shells are of equal thick (prefer 1-2 mm thick) and having good corrosive, heat resistant properties. In between these two shells a ceramic blanket (3) of thickness l-3mm is sandwiched. Chemical composition of ceramic blanket/ cerablanket
(3) is very good to sustain very high temperatures. Also, it has good sound absorbing & heat insulation properties. Instead of using a single shell of higher thickness, the above mentioned arrangement which is more effective, is given to reduce the inside noise radiation (i.e. - doubling effect for better noise reduction). In addition to this, it prevents the outer surface of the muffler from excessive heating. The Assembly Inlet Pipe (8) is welded with both the muffler shells tangentially. It consists of an inlet pipe (8a) and pipe flange (8b). Inlet pipe (8a) having thickness of l-3mm, is inserted into the central hole of Pipe flange (8b) by 4-6 mm & welded throughout the inlet pipe contour. There are another four holes provided on pipe flange (8b) to mount with flange of exhaust pipe assembly. This tangential entry arrangement of assy inlet pipe (8) helps to create vortex flow of gases inside the muffler.

There are two covers namely front end cover (4) and rear end cover (5), used to complete the muffler volume. Those covers have the same outer diameter, thickness and material properties. The only difference is that a concentric hole of it is provided in rear end cover (5) for passing of Exhaust gas through the Muffler Outlet pipe (9). The fitment of both these end covers with muffler shell is just reverse. The rear end cover (5) fitment is same as conventional practice. The Front End cover (4) is fitted in such a way that muffler volume is fully utilized at entry side of muffler. Process wise its (front end cover) fitment sequence is just before the tail pipe (12) fitment.
A perforated baffle (6) is fitted near the assy inlet pipe (8).Its Diameter, thickness and material properties are also same as end covers. In its (6) design some special features are added to prevent the Glass wool bag l(10).The Glass wool bag 1(10) is placed between the Front End cover (4) and the perforated baffle (6).The temperature of exhaust gas is comparatively too high at entry of muffler than the exit and in high temperature zones there is a chance of losing the properties of Glass wool. So at the entry side of muffler into the perforated baffle (6) the percentage of porosity is kept between 2-4%. Also, perforations are done randomly/alternate rows to prevent chocking of it (6).
Another, perforated element namely conical perforated tube (7) is used in the rear half of this muffler. This is welded with the Rear End cover (5) and inner shell (2). The material properties of the conical perforated tube (7) are same as both the end covers and perforated baffle. The percentage of porosity is 5-10% of this conical perforated Tube (7) because of same reason as stated in the previous paragraph. The Conical perforated Tube (7) guide the Exhaust Gases towards tail pipe gradually increasing the velocity of it due to convergent effect and helps to reduce the back pressure of the gases. The perforations are done on conical perforated tube (7) of hole-diameter of 5-7 mm, alternate rows to avoid chocking in rows. The semi-conical angle of this tube is designed in accordance with muffler OD (Outer Diameter) and some imperial calculation basis. Outside this Conical Perforated Tube (7) i.e. - in between the inner shell (2), rear end cover (5), Glass wool bag 2 (11) is placed. Glass wool bags (Both the glass wool bags) used for this

muffler, have the same density of 115-135 kg/m3. It is manly used in any muffler because of its sound absorbing properties. It has a limitation in thermal stability. The glass wool bags are used inside the muffler considering the temperature distribution. Actually, glass wool bag (absorbent material) is effective for absorbing high frequency Noise of pulsating exhaust gases coming out of the engine. The rear half i.e. - conical perforated tube region is more effective as the perforation area/ surface contact area gas is larger,
The Outlet pipe (9) is inserted into and welded with Rear End cover (5). This out let pipe is designed in such a Faison that rear end cover (5) is also used for clamping of Tail pipe (12). The outlet pipe (12) diameter is not uniform through out its length. OD of the rear half of outlet pipe is kept same as the OD of central hole/pass way of Rear End cover (5). Because of this arrangement total length of assy muffler with tail pipe reduce by 12-17 mm. The present muffler is designed with 30-60 mm short shell length. In totality, the overall length of the muffler is reduced by 40-80mm. Present muffler is developed with 2-7% lesser volume than the existing branded muffler. Positively, it will help to accommodate the muffler with various widths for vehicles such as Medium and Heavy Commercial Vehicles. After fitment of all aggregates in Medium and Heavy Commercial Vehicles, there are usually constraints of space to fit proper muffler (i.e.-size & effectiveness). Because of this sometimes, the vehicle manufacturers have to compromise with performances of Mufflers.
The tail pipe (12) is clamped with the muffler outlet pipe (9) with pipe clamp (13) and its fasteners (14). This arrangement gives the facility of changing its (12) orientation as per the vehicle requirement. It is possible to fit it (12) by rotating any angle in any orientation. This type of arrangement helps to increase the ford-ability from the existing muffler if both cases mounting poison of mufflers remain same for a particular vehicle, so that the vehicle can also move in swampy and water logged area. Because of the axial outlet of exhaust gases in existing prior art muffler the ford-ability has to suffer.

The material and thickness used in both tail pipe (12) and outlet pipe (9) are same. The pipe clamp (13) used here is conventional. For clamping hex-screw, spring washer & nyloc nut is used as fastener as conventional practice.
In this muffler sound absorbing material is used for reduction of noise. Further, it is stated in objective that vortex flow principle is also introduced in current muffler. Some brief details are mentioned in this paragraph. Any type of chambers use for attenuation of noise is a kind of reactive muffler. Here, mainly sound amplitude is reduced by reflection process. Application of vortex flow principle is newer for design of Commercial Vehicles muffler. Here, exhaust gas enters the muffler tangentially & exits axially. In a single sentence, this type of arrangement increases the axial velocity in addition to expansion effects like the conventional expansion chamber type reactive muffler. Vortex flow helps to increase the velocity at the cost of decreasing the pressure fluctuations.
This is the main advantage of vortex flow arrangement and reduces the back pressure in compare to entry of exhaust gas through extended perforated inlet pipe (as in existing muffler). Further, conical perforated tube is used in the rear half of muffler. This provides the convergent effect i.e. - increase the velocity of gas. The combination of these two effects help in better scavenging of engine. The vortex created inside the muffler is a free vortex because there is no device to create it. Only thing that inlet pipe arrangement and inside components are placed in such a way that it suits to this kind of flow principle.
Performances of the proposed system has been verified in comparison with the existing. Cost effectiveness of this muffler is evaluated. It is seen that manufacturing cost of this muffler reduces from existing muffler by 20-30% without compromising the performance/effectiveness.
As, early mentioned the present muffler volume is 2-7% lesser than existing. So, that present muffler is more effective than the existing muffler.

A catalytic element can be paced instead of use only glass wool bag 2(11) in between the Conical perforated tube (7), Rear end cover (5) & inner shell (2). Its helps to improve the exhaust emission level and make the vehicle environment friendly.
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. A cost-effective vortex flow type exhaust muffler comprising of
a muffler body comprising two layers outer shell (1) and inner shell (2);
at least one ceramic blanket (3) sandwiched inside said outer shell (1) and inner shell (2) to reduce the inside noise radiation and increase insulation properties;
at least one front end cover (4) and one rear end cover (5) configured to complete the muffler volume;
at least one conical perforated tube (7) fastened to said rear end cover (5) and said inner shell (2);
at least one assembly inlet pipe (8) fastened on both the muffler shell tangentially consists of an inlet pipe (8a) and pipe flange (8b);
at least one perforated baffle (6) fitted near said assembly inlet pipe (8);
at least one glass wool bag 1 (10) is placed between the front end cover (4) and said perforated baffle plate (6) to absorbs the high frequency noise of pulsating exhaust gas;
at least one glass wool bag 2 (11) is placed between said inner shell (2) and said conical perforated tube (7) to absorbs the high frequency noise;
at least one outlet pipe (9) configured to be inserted into and fastened with rear end cover (5); and
at least one tail pipe (12) clamped with the said muffler outlet pipe (9) and rear end cover (5) together with pipe clamping arrangement (13) and (14).
2. The exhaust muffler as claimed in claim 1 wherein said assembly inlet pipe (8) fastened on both the muffler shell tangentially such that creating a vortex flow of the gases inside the muffler.
3. The exhaust muffler as claimed in claim 1 wherein said assembly inlet pipe (8) welded to muffler shells tangentially to create vortex flow of gases inside the muffler consists of an inlet pipe (8a) and pipe flange (8b) such that inlet pipe (8a) is inserted into the central hole of pipe flange (8b) fastened throughout the inlet pipe contour and

four holes provided on pipe flange (8b) to mount with flange of exhaust pipe assembly.
4. The exhaust muffler as claimed in claim 1 wherein said conical perforated tube (7) is configured for guiding the exhaust gases towards tail pipe (12) by gradually increasing the velocity of gases by the converging effect and to reduce the back pressure of the gases.
5. The exhaust muffler as claimed in claim 1 wherein said clamping arrangement of said tail pipe (12) with the muffler outlet pipe (9) with pipe clamp and related fasteners facilitates change in orientation of tail pipe (12) as per the vehicle requirement.
6. The exhaust muffler as claimed in claim 1 wherein to improve the exhaust emission quality a catalytic element is placed along with said glass wool bag 2 (11) by considering packaging between the conical perforated tube (7), rear end cover (5) and muffler inner shell (2).
7. The exhaust muffler as claimed in claim 1 wherein said front end cover (4) and rear end cover (5) have the same outer diameter, thickness and material properties.
8. The exhaust muffler as claimed in claim 1 wherein said rear end cover (5) is provided with a concentric hole for passing of exhaust gas through the muffler outlet pipe (9).
9. The exhaust muffler as claimed in claim 1 wherein said perforated baffle (6) provided with perforations randomly/alternate rows to prevent chocking is configured to reduce temperature of exhaust gas to retain the properties of glass wool bag 1 (10).
10. The exhaust muffler as claimed in claim 1 wherein said conical perforated tube (7) provided with perforations at alternate rows to avoid chocking in rows is configured to guide exhaust gases towards tail pipe gradually increasing the velocity of it due to

convergent effect and helps to reduce the back pressure of the gases and the material properties of said conical perforated tube (7) are same at both the end covers and perforated baffle,
11. The exhaust muffler as claimed in claim 1 wherein said tail pipe (12) clamped with the said muffler outlet pipe (9) and rear end cover (5) together with pipe clamping arrangement reduces total length of assembly muffler to facilitate accommodation of muffler with various widths for vehicles such as medium and heavy commercial vehicles thereby avoiding compromise with performances of mufflers due to constraints of space to fit proper muffler.
12. The exhaust muffler as claimed in claim 1 wherein said pipe clamping arrangement (13) and (14) facilitates changing of tail pipe (12) as per the vehicle requirement by rotating any angle in any orientation to increase the ford-ability from the existing muffler and to drive vehicle in swampy and water logged area.
13. The exhaust muffler as claimed in claim 1 wherein the exhaust gas enters the muffler tangentially and exits axially thereby increasing the axial velocity of gases in addition to expansion effects and decreasing the pressure fluctuations.
14. The exhaust muffler as claimed in claim 1 wherein vortex flow arrangement and convergent effect due to conical perforated tube are configured for better scavenging of engine.
15. The cost-effective vortex flow type exhaust muffler substantially as herein described with reference to accompanying drawings.