FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION Exhaust muffler assembly with heat recovery unit
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
INVENTOR
Sanjoy Biswas
An 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.

TECHNICAL FIELD
The present invention generally relates to combined exhaust and cabin heating system of the automobiles and more particularly relates to an integrated heat exchanger and exhaust muffler assembly.
BACKGROUND OF THE INVENTION
Utilization of heat energy of exhaust gas has become a major research area in automobile. In today's scenario, exhaust gas has effective use in emission control (i.e.-EGR) in line with very selective application for other areas. Generally, water heater and combustion (Webasto) heater type cabin heating system are employed. Typically, such heaters are applicable for very low ambient conditions, where occupants may require continuous heat, even when vehicle is in an idle condition (i.e. engine not working). On the other hand, engine coolant is circulated through heater whose circuit is parallel to engine external cooling circuit in water heater type cabin heating system (refer Fig-1).
Further, many cases fitment, packaging, handling and, particularly servicing, of the conventional exhaust mufflers, remains to be major issue. Since the conventional exhaust mufflers are not conveniently serviceable, it frequently becomes inevitable to scarp the entire muffler when the muffler is damaged.
OBJECTS OF THE INVENTION
The objective of invention is to provide a reliable, simple and economical muffler assembly for a vehicle.
Another object of the present invention is to provide an integrated heat exchanger and exhaust muffler assembly, which can be conveniently dismantled.

Another object of the present invention is to provide an exhaust muffler which is capable of recovering heat from exhaust of the vehicle and using the same for cabin heating purposes.
Another object of the present invention is to provide a muffler assembly which is approx 20% less in both volume and weight, but will reduce noise level as per norms, without crossing backpressure limit of engine.
Another object of the present invention is to provide a muffler assembly which is robust and, can be manufactured easily in less time.
Further objects and features of the invention will become apparent from the following detailed description when considered in conjunction with the drawings.
SUMMARY OF THE INVENTION
The various embodiments of the present invention relate to a muffler assembly with an integrated heat recovery unit for a vehicle. The muffler assembly comprises a first outer tubular member, a first inner tubular member connected to an exhaust of a vehicle and substantially received within the first outer tubular member for communicating the exhaust gases from the exhaust of the vehicle, an exhaust heat recovery unit connected to the first outer tubular member, communicating the exhaust gasses to therethrough, a second outer tubular member connected to the exhaust heat recovery unit, and a second inner tubular member substantially received within the second outer tubular member and a free end portion of the second.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a schematic layout of a system utilizing the muffler assembly, according to an embodiment of the present invention,

FIG. 2 illustrates a sectional side view of the muffler assembly, according to an embodiment of the present invention,
FIG. 3 illustrates a sectional top view of the muffler assembly, according to an embodiment of the present invention, and
FIG. 4 illustrates a perspective view of view of the muffler assembly, according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE 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.
FIG. 1 illustrates a schematic layout of a system 100 utilizing a muffler assembly 200, according to an embodiment of the invention. The proposed system 100 is basically working as an exhaust muffler as a whole having arrangement of heat recovery unit inside of it. The heat recovery unit is a kind of heat exchanger and which will work on reverse phenomenon of intercooler. It is mainly high performing Fin-Tube type Compact heat exchanger. The proposed device will help to attenuate the noise as per desired level or norms like any (effective or well designed) exhaust muffler inline to recover the heat. Recovered waste heat will be used for heating the cabin. There is no need of using water heater in proposed cabin heating.
The muffle assembly 200 for a vehicle (not shown), in accordance with various embodiments of the present inventions is disclosed in FIGS, 2 through 4. The muffler assembly includes a first outer tubular member 202. A first inner tubular member 204 connected to an exhaust (not shown) of the vehicle. The first inner tubular member 204 is substantially received within the first outer tubular member

202. The first inner tubular member 204 communicates the exhaust gases from the exhaust of the vehicle, to the space defined by the first outer tubular member 202. In an embodiment of the present invention, the space enclosed between the first outer tubular member 202 and the first inner tubular member acts as a reactive chamber.
An exhaust heat recovery unit 206 is connected to the first outer tubular member 202. The exhaust heat recovery unit 206 allows the communication of the exhaust gasses to therethrough. A second outer tubular member 208 is connected to the exhaust heat recovery unit 206. A second inner tubular member 210 substantially received within second outer tubular member 208. A free end portion 212 of the second inner tubular member 210 is positioned substantially outside the second inner tubular member 210.
The first inner tubular member 204 also includes a plurality of holes on both periphery and axial direction disposed on the portion within the first outer tubular member 202. First inner tubular member 204 is an assembly of a tubular member, a divergent tube and a perforated end plate. A diverging portion 214 is provided with the first inner tubular member 204. The diverging portion 214 has a perforated end plate 216 facing the exhaust heat recovery unit 206. In an embodiment, the tubular member whose one end is flared and another end is perforated type. Flared end of tubular member of first inner tubular member 204, is use to fit with exhaust pipe of vehicle. Whereas perforated end of tubular member of first inner tubular member 204, is connected with divergent tube using welding joint. Perforated end plate is fitted with divergent tube. Perforation on tubular member (of first inner tubular member 204) is on periphery at certain pitch and at alternate rows to avoid chocking of holes
The exhaust heat recovery unit 206 includes a plurality of horizontal passages 218. The plurality of horizontal passages 218 allow exhaust gases from the first inner tubular member 204 to reach a space defined by the second outer tubular member 208, therethrough. Further at least one vertical pipe passes laterally through the

plurality of horizontal passages. It shall be apparent to those skilled on the art that a heat transfer takes place between gasses in the at least one vertical pipe and exhaust gasses passing through the plurality of horizontal passages 218.
In an embodiment, the exhaust heat recovery unit 206 is X-flow fin-tube type high performing heat exchanger. Fin spacing 4-6 fin/inch in this exhaust heat recovery unit 206 considering the effect of backpressure. Fins are made of Aluminum and tubes are made of copper. For proper clamping of inlet and outlet duct pipes of cabin heating system two numbers of beading are provided on inlet 220 & outlet 220 of heat exchanger.
The exhaust heat recovery unit 206 is removably bolted to the first outer tubular member 204 and the second outer tubular member 208. As best shown in FIG. 2, as per one embodiment of the inventions, the exhaust heat recovery unit 206 is supported by a pair of covers for exhaust heat recovery unit 206, and the first outer tubular member 204 and the second outer tubular member 208 are removably connected, for example bolted, to opposite sides of the pair of covers for the exhaust heat recovery unit 206. Also, one no of gasket is used in each side to prevent any leakage. Wall plate of each unit of muffler (defined by the first outer tubular member 204 and the second outer tubular member 208) and gasket are nearly structurally similar. Gasket may be made of asbestos free, heat resisting material of about 4-6 mm thickness. A perforated baffler 222 is disposed within the second outer tubular member 208. The perforated baffler 222 divides the second outer tubular member in two chambers. In an embodiment of the present invention, the space enclosed between the second outer tubular member 208, the second inner tubular member 210 and the perforated baffler 222 acts as a reactive cum absorptive type. Considering environmental effect, very small amount of glass/ceramic wool is placed on an absorptive cell around a portion of second inner tubular member 210. The absorptive cell is created around second inner tubular member 210 using two more parts namely outer perforated pipe, absorptive cell baffle. Outer perforated pipe is welded concentrically with respect to second inner

tubular member 210 with rear end cover of second outer tubular member 208. A central portion 224 of the perforated baffler 222 is free from perforations to preclude direct entry of exhaust gasses to the second inner tubular member. This indirectly helps to restrict the flow of exhaust gases directly therethrough. Because of this noise attenuation performance will improve. As shown in FIGS, a portion of second inner tubular member positioned within the second outer tubular member 208 includes a plurality of perforations, on periphery and at alternate pitch, having a sound absorptive material wrapped therearound. Particularly, a very small amount of glass/ceramic wool is wrapped. According to a preferred embodiment of the present invention, the muffle assembly 200 is basically a serviceable type exhaust muffler with an integrated heat recovery unit. Fundamentally, it is also a combination or hybrid type muffler but inside configuration is completely different from conventional. Further, it is approx 20% lesser in both volume and weight wise than existing variants.
The total muffler volume is divided into three units. The heat recovery unit is placed between first and last unit using two gaskets at both side. The heat recovery unit functions like a baffle in the device. The first unit is basically a single chamber whereas the last unit is divided into two numbers of chambers of almost same size using a unique type of perforated baffle. Both the first unit (/chamber) and the first chamber of last unit is reactive type whereas the last chamber of the last unit is reactive cum absorptive type. Due to the noise attenuating features stated above proposed device or muffler is combination or hybrid type.
The first unit and first chamber of last unit are connected through passages of core heat recovery unit. The heat recovery unit is basically consisting of a heat exchanger and two covers. The cover is the Assy of one half shell, 2 no. of side Rib, 4 no of end rib and 10 no of hex. Weld nut. Here, Hex. The weld nut is fitted on side rib of covers. The heat exchanger is kind of an X-flow fin-tube type compact heat exchanger. Fin spacing is 4-6 fin/inch in this heat exchanger

considering the backpressure. Another important factor of this design is to select proper diameter for tube, no of tube and its placement. First two factors of tube are calculated based one flow requirement for cab/cabin heating. Placement of tube is to be done in zigzag pattern to ensure minimum flow restriction of hot fluid. Here hot fluid is exhaust gases. Fins are made of Aluminium and tubes are made of copper. For proper clamping of inlet and outlet duct pipes of cabin heating system two numbers of beading are provided on inlet & outlet of heat exchanger. The unit (i.e. both heat exchanger and its cover) is mounted through bolting joints with both first and last units of muffler. Also, both the covers are mounted in between using bolting. Space between covers and heat exchanger is inactive or dead zone of heat recovery unit. Hence, Fitment of gasket on each side of heat recovery unit is very much essential to prevent leakage (to dead zone or in outside the device).Gasket is made of asbestos free heat resisting material of 4-6 mm thick. Profile of gasket is same as wall plate.
The first unit is comprises of an Assy inlet pipe, front end cover, wall plate Assy and shell. The shape of the shell is elliptical for this typical design. Flange portion of front end cover is inserted and continues welded with shell. In other, hand wall plate Assy is fillet welded at other end of front unit. Wall plate Assy is made of a wall plate and 2 numbers of hex. Weld nuts. These two hex. Weld nuts are used for mounting of heat exchanger. In first unit or chamber, assy inlet pipe is inserted centrally, welded with front end cover. Assy inlet pipe is consists of perforated pipe, divergent pipe and inlet pipe baffle. One end of perforated pipe is flared which is use to fit with exhaust pipe of vehicle other end of pipe is with perforation on periphery at certain pitch and at alternate rows to avoid chocking of holes. Smaller diameter end of divergent pipe is welded with perforated end of perforated pipe though out its contour. In other side of divergent pipe an inlet pipe baffle is fitted using welding joint. Inlet pipe baffle is also consisting of perforation and this is made concentrically in different PCD (pitch circle diameter). Diameter of hole for perforation in both perforated pipe and inlet pipe baffle is within 7 to 9 mm.

Thickness of all child parts of Assy inlet pipe is within range of 1.25 to 2 mm. Opening area ratio for this Assy inlet pipe is kept between 1.85 to 2.25 to margin the exhaust backpressure within the recommended value of engine manufacturer. Here, outlet end of Assy inlet pipe is divergent type for better flow distribution near heat recovery unit core. Also, thickness and material of shell, wall plate and front end cover are same in front unit.
The last unit is comprises of an outlet pipe, outer perforated pipe, absorptive cell baffle, perforated baffle, rear end cover, wall plate Assy and shell. The unit is divided into two numbers of chambers of almost same size by this perforated baffle. First chamber of last unit is reactive type by principle of noise attenuation whereas last chamber of last unit is reactive cum absorptive type. Both this cambers are connected trough perforation holes of perforated baffle. The configuration of last chamber of last unit is quite unique in proposed muffler. In last chamber of last unit; an outlet pipe is inserted centrally and welded with rear end cover. An absorptive cell is created around and at inlet end of out let pipe. To make this absorptive cell, two more parts namely outer perforated pipe, absorptive cell baffle required. Outer perforated pipe is welded concentrically with respect to outlet pipe with rear end cover. Considering environmental effect, very small amount of glass/ceramic wool is placed in that absorptive cell around outlet pipe. Absorptive cell baffle is used enclosed absorptive material and it is welded with both outer perforated pipe and outlet pipe. As name suggests, the outer perforated pipe consists of perforation on periphery at alternate pitch. Also, inlet end of outlet pipe have the perforation. Further, absorptive cell baffle consist of perforation hole in only one PCD for improved noise attenuating performance of last chamber by absorptive or dissipative principle. Diameter of perforation use for outlet pipe, outer perforated pipe, and absorptive cell baffle are same to avoid any ambiguity during manufacturing but this size is lesser that other perforation used in perforated baffle or first unit. Hole-size is kept within 4 to 7 mm to ensure minimum chances to cum out burn absorptive material (glass/ceramic wool) to environment.

The perforated baffle used in last unit has no perforation at central area thereof. This indirectly helps to restrict the flow of exhaust gases directly from first chamber to outlet pipe. Because of this noise attenuation performance of second chamber will improve. This so as exhaust gases comes to second chamber from first initially through perforated baffle. Then gases circulate inside the 2nd chamber and both reactive/reflective & absorptive effect help to reduction of noise before it expel to environment trough outlet pipe. Hole-size of perforation on perforated baffle is in the range of 7-9 mm unlike Assy inlet pipe. Further, flange depth of this baffle is half of both front and rear end cover. Shape and length of this shell is same as first unit. Also, wall plate Assy is same. All except the central opening, other features of rear end cover is same as front end cover. Further, thickness and material of shell, wall plate, perforated baffle and front end cover are same in rear unit like the front unit. Thickness of these is 1.5-2mm. Length of both front and rear unit is same. It is 40-45% of total length of device or muffler assembly.
The foregoing description provides specific embodiments of the present invention. It should be appreciated that these embodiment are described for purpose of illustration only, and that numerous other 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.

Referral
Numerals Description
100 System
200 Muffler assembly
202 First outer tubular member

204
First inner tubular member
206 Exhaust heat recovery unit
208 Second outer tubular member
210 Second inner tubular member
212 Free end portion
214 Diverging portion
216 Perforated end plate
218 Plurality of horizontal passages
220 Inlet and outlet of the vertical pipe
222 Perforated baffler
224 Central portion

We claim;
1. A muffler assembly for a vehicle, the muffler assembly comprising,
a first outer tubular member,
a first inner tubular member connected to an exhaust of a vehicle and substantially received within the first outer tubular member for communicating the exhaust gases from the exhaust of the vehicle,
an exhaust heat recovery unit connected to the first outer tubular member, communicating the exhaust gasses to therethrough,
a second outer tubular member connected to the exhaust heat recovery unit,
and
a second inner tubular member substantially received within the second outer tubular member and a free end portion of the second inner tubular member positioned substantially outside the second inner tubular member.
2. The muffler assembly as claimed in claim 1, wherein the first inner tubular member includes a plurality of holes disposed on the portion within the first outer tubular member.
3. The muffler assembly as claimed in claim 2, wherein a converging portion is provided with the first inner tubular member, the converging portion having a perforated end plate facing the exhaust heat recovery unit.
4. The muffler assembly as claimed in claim 1, wherein the exhaust heat recovery unit includes,
a plurality of horizontal passages allowing exhaust gases from the first inner tubular member to reach a space defined by the second outer tubular member, and
at least one vertical pipe passing laterally through the plurality of horizontal passages, such that heat transfer takes place between gasses in the at least one vertical pipe and exhaust gasses passing through the plurality of horizontal passages.

5. The muffler assembly as claimed in claim 1, wherein the exhaust heat recovery unit is removably bolted to the first outer tubular member and the second outer tubular member.
6. The muffler assembly as claimed in claim 1, wherein a perforated baffler is disposed within the second outer tubular member, the perforated baffler dividing the second outer tubular member in two chambers.
7. The muffler assembly as claimed in claim 1, wherein a central portion of is free from perforations to preclude direct entry of exhaust gasses to the second inner the perforated baffler tubular member.
8. The muffler assembly as claimed in claim 1, wherein a portion of second inner tubular member positioned within the second outer tubular member includes a plurality of perforations having a sound absorptive material wrapped therearound.