CN115461530A

CN115461530A - Noise processing unit for a motor vehicle

Info

Publication number: CN115461530A
Application number: CN202180026938.9A
Authority: CN
Inventors: B·森蒂尔库马尔; M·布巴兰
Original assignee: TVS Motor Co Ltd
Current assignee: TVS Motor Co Ltd
Priority date: 2020-04-15
Filing date: 2021-04-15
Publication date: 2022-12-09
Also published as: EP4136330A1; WO2021210020A4; WO2021210020A1; EP4136330A4

Abstract

The present subject matter relates to an exhaust system for a motor vehicle having a noise treatment unit (225), wherein the noise treatment unit acts like a muffler. The noise treatment unit (225) is part of an exhaust system (102) which is connected to the internal combustion engine (101). The noise processing unit (225) comprises one or more intermediate chambers (311) selectively physically arranged between the plurality of first chambers (301, 302). One or more second chambers (321) are disposed behind the plurality of first chambers (301, 302). The noise treatment unit (225) is configured to direct the exhaust gas to flow through the plurality of first chambers (301, 302), then through the one or more intermediate chambers (311), and then through the one or more second chambers (321). The noise processing unit (225) occupies less space and performs effective noise attenuation.

Description

Noise processing unit for a motor vehicle

Technical Field

The present subject matter relates to a noise processing unit for a motor vehicle, and more particularly, but not exclusively, to a noise processing unit for a two-or three-wheeled motor vehicle.

Background

Typically, a motor vehicle powered by an Internal Combustion (IC) engine will be equipped with an exhaust system connected to the exhaust of the IC engine. Exhaust systems are used to discharge exhaust gases, including carbon monoxide, hydrocarbons, nitrogen oxides, etc., into the atmosphere as a result of combustion of an air-fuel mixture in one or more combustion chambers of an IC engine of a motor vehicle. In addition to being used for treating exhaust gases, exhaust systems are also used for attenuating noise generated by the combustion process.

Generally, in certain interesting and risky applications (e.g., racing), noisy motor vehicles may be preferred, where noise attenuation is also not critical. However, in commuting applications, the noise emanating from the motor vehicle is undesirable in view of noise pollution and other requirements to be met in public places.

Drawings

The embodiments are described with reference to the accompanying drawings, which relate to a two-wheeled motor vehicle as one embodiment of the invention. However, the invention is not limited to the described embodiments. In the drawings, the same or similar numbers are used throughout to refer to features and components.

Fig. 1 illustrates a left side view of an exemplary motor vehicle, according to an embodiment of the present subject matter.

Fig. 2 shows a right side view of an exemplary internal combustion engine having an exhaust system, according to an embodiment of the present subject matter.

Fig. 3 (a) shows a schematic diagram of a noise processing unit according to an embodiment of the present subject matter.

Fig. 3 (b) shows a schematic cross-sectional view of a noise processing unit according to an embodiment of the present subject matter.

Fig. 3 (c) depicts another cross-sectional view of a noise processing unit according to an embodiment of the present subject matter.

Fig. 3 (d) shows an enlarged view of a portion of the noise processing unit according to an embodiment of the present subject matter as shown in fig. 3 (c).

Detailed Description

Conventionally, in order to make the exhaust sound small, motor vehicles have employed various methods such as increasing the surface area/volume of a portion of the exhaust system, where the exhaust gas generally expands within the muffler. In certain other approaches known in the art, a multiple tailpipe or split exhaust system is used. All of these approaches increase the overall size of the exhaust system including the muffler. Generally, the above solution is implemented in large capacity motor vehicles, like four-wheel motor vehicles or multi-wheel motor vehicles with more than four wheels. Such motor vehicle bodies are large and have a range for accommodating even longer and larger split exhaust systems. Similar solutions have been attempted for large capacity two-or three-wheeled motor vehicles, which typically have a larger vehicle area or a longer track. However, the above solution is not practical for smaller capacity commuter vehicles with compact vehicle layout or relatively small track. Furthermore, the foregoing solution increases the manufacturing cost of the vehicle, so that it is impractical to implement the foregoing solution in a motor vehicle of low cost and smaller capacity.

For example, two-wheeled motor vehicles typically have a naked appearance, at least in the rear portion thereof. On such vehicles, various critical components such as an IC engine are compactly packaged between the two wheels. Some two-wheeled motor vehicles may even have storage space for carrying loads or cargo, which requires additional utility space on the vehicle that cannot be affected or reduced. In these vehicles, the exhaust system is carefully guided away from critical components of the motor vehicle and the rider, so it is typically positioned toward the rear of the vehicle to limit the amount of heat dissipated toward the critical components or the rider and/or rear seat. In some other attempts to address this problem, control valves are provided within the muffler to direct air through various tubes or chambers. Accommodating such a valve and such multiple channels requires additional volume in the muffler and also requires a mechanical or electronic actuator to control the valve, thereby increasing the cost of the system. The additional volume created on the already compact motor vehicle increases the size of the exhaust system, which can interfere with other components of the motor vehicle or with riders on the rear seat. Furthermore, the increased size of the exhaust system is also a challenge to appearance and can cause a disproportionate appearance, which is undesirable.

Therefore, in motor vehicles having exhaust system designs that face the aforementioned conflicting space-related and layout issues, it is a challenge to provide an effective noise treatment unit like a muffler. Curve a depicted in fig. 4 shows an exemplary attenuation curve for a typical small capacity motor vehicle at various frequencies. As can be seen, there are some pulses and sharp rises and falls in the attenuation at different frequencies, while at other parts the noise attenuation is almost negligible. This can make the exhaust noise very disturbing due to the poor attenuation, making it noisy for the rider and passersby.

Further, exhaust systems or mufflers in two-or three-wheeled motor vehicles have one or two mountings therefor, thereby constituting a major challenge for mounting such complex exhaust systems. For example, a mounting portion like a mounting bracket is used as a connecting member between the muffler and a frame assembly or a chassis of a motor vehicle. There may be material defects around the welded area where the mounting bracket is attached to the muffler, making this portion of the muffler a heat affected zone and susceptible to durability failure. Additionally, the weld temperature typically reaches 1000 ℃, thereby affecting the mechanical properties of the heat affected zone, ultimately leading to undesirable failure, resulting in damage or performance degradation of the exhaust system, the noisy exhaust system.

Accordingly, there is a need for an exhaust system that can provide noise attenuation under almost all operating conditions of an IC engine. The exhaust system should be compact to implement even in motor vehicles with a small wheel track. Further, the exhaust system should be cost effective and should be easy to install with rigid mounts without requiring any modification to existing frame assemblies or chassis.

The exhaust system according to the invention comprises a noise treatment unit having a compact construction to be accommodated on a compact motor vehicle. In one embodiment, the noise handling unit includes a plurality of chambers configured to effectively attenuate noise across different frequencies without occupying too much space.

In one embodiment, the noise processing unit includes a plurality of first chambers, one or more second chambers, and one or more intermediate chambers. The plurality of first chambers substantially form an upstream chamber. One or more intermediate chambers are optionally physically disposed between the plurality of first chambers. One or more second chambers form a downstream chamber. The noise treatment unit is configured to direct the exhaust gas flow through the plurality of first chambers, then through the one or more intermediate chambers and through the one or more second chambers for effective noise attenuation across a large frequency range.

In one embodiment, the exhaust gas passes through a number of first chambers and then through an intermediate chamber. For example, in the case of two first chambers, the noise reduction unit or the noise treatment unit may be configured such that the exhaust gas passes through both the first chambers and then through one or more intermediate chambers.

In one embodiment, the one or more intermediate chambers comprise a cumulative volume that is less than a cumulative volume of any of the plurality of first chambers and the one or more second chambers. Thus, the first chamber having a larger volume can achieve expansion of the exhaust gas entering the noise treatment unit at a faster rate. The larger first chamber enables a reduction in energy and corresponding noise due to efficient expansion.

In one embodiment, the intermediate chamber with the smaller volume is configured to act on large frequency waves that are attenuated there due to substantial changes in area and volume. The chambers are configured to produce internally reflected relative phase sound waves of various frequencies that are selectively cancelled across the chamber to produce a desired sound effect.

In one embodiment of the invention, one or more intermediate chambers are selectively disposed between the plurality of first chambers in a predetermined arrangement. The one or more intermediate chambers are configured to change a flow direction of the exhaust gas in two or more directions. This increases the travel path of the exhaust gas, thereby enhancing the dissipation of thermal energy.

In one embodiment, the plurality of first chambers, the one or more intermediate chambers, and the one or more second chambers are disposed adjacent along an axis of the noise treatment unit. Since each chamber is arranged adjacent to the other along the axis, any expansion in size, such as in the vertical direction, is avoided, thereby not affecting the position of the current backseat footrest and the position of other critical components. Thus, by substantially maintaining the cross-sectional area of the cell, thereby even generating at least two directional changes in the exhaust flow, the present subject matter achieves effective noise attenuation.

In one embodiment, the one or more intermediate chambers of the noise treatment unit comprise at least one intermediate chamber disposed substantially at the middle of the noise treatment unit. In one embodiment, the at least one intermediate chamber is formed by a first baffle and a second baffle, and the baffles will be arranged adjacent to each other to form a smaller volume, and the centrally located baffle is able to maintain structural integrity during welding of mounting members and the like due to the large surface area at this region. Further, the construction of the noise treatment unit eliminates the need to provide perforations on the baffle itself, as the perforations can affect the structural integrity of the baffle.

In one embodiment, the noise processing unit includes a mounting member, and the mounting member is fixed to a housing of the noise processing unit at a portion near the intermediate chamber. Even if welding is performed on the housing, the baffle disposed nearby provides additional area to accommodate higher heat during welding, etc.

In one embodiment, the noise treatment unit includes a plurality of connectors configured to bypass the chambers disposed in close proximity to provide a longer flow path and also to be able to change the flow direction by bypassing the close proximity chambers. The connector is provided with an optimal length for establishing a connection between the chambers without the need to extend the connector along the entire length of the noise treatment unit.

In one embodiment, at least two connectors passing through the baffle are provided at positions offset from the axis of the noise handling unit for optimal accommodation of components without taking up a large space. For example, in one embodiment, three connectors are received on the baffle and three connectors are disposed at positions offset from an axis of the noise treatment unit, which is generally centered on the noise treatment unit.

In one embodiment, the noise processing unit is configured for use with a compact vehicle that includes a wheel base ranging between 1200-1400 millimeters.

In one embodiment, an exhaust system includes an exhaust pipe having an outlet portion. The outlet portion includes an extension that extends at least partially into one of the plurality of first chambers. The one or more second chambers include an exhaust for exhausting gas to the atmosphere. At least one of the outlet portion and the exhaust pipe is provided with perforations configured to diffuse exhaust gas during entry and exit from the noise treatment unit.

In one embodiment, the intermediate chamber is configured to attenuate high frequency waves in the exhaust gas, the high frequency waves being greater than 4000Hz, causing discomfort to the human ear. In one embodiment, a second chamber having a cumulative volume greater than the first chamber is configured to attenuate frequency waves in the range of 1500Hz to 3000Hz with at least two directional changes or flow reversals, which generally produce metallic sound. Therefore, by generating the desired necessary exhaust noise, the exhaust gas discharged from the noise processing unit can be pleasant to the rider and passersby.

Therefore, the exhaust gas, which is discharged from the IC engine at a high speed and passes through the narrow exhaust pipe, is effectively attenuated from noise/sound before being discharged into the atmosphere.

The exhaust system may be implemented in any two-wheeled vehicle or three-wheeled motor vehicle. However, for purposes of illustration and not limitation, an exhaust system, and corresponding other advantages and features, are described by the following embodiments. The arrow placed anywhere in the upper right corner of the figure represents a direction relative to the motor vehicle. Arrow F indicates a forward direction, arrow R indicates a backward direction, arrow UW indicates an upward direction, and arrow DW indicates a downward direction.

Fig. 1 shows a left side view of an exemplary motor vehicle 100 according to an embodiment of the invention. Motor vehicle 100 includes a frame assembly 105 that is a structural member of motor vehicle 100. The frame assembly 105 includes a head tube 111, a main tube 105 (shown schematically in phantom) extending downwardly and rearwardly from the head tube 111. The motor vehicle includes front wheels 110, rear wheels 103, a fuel tank 121, and a seat 106. In one embodiment, frame assembly 105 includes a main tube 112, a down tube (not shown), and one or more seat rails (not shown) extending rearward from main tube 112. The head pipe 111 supports a steering shaft (not shown) and a front suspension 114 (only one is visible), the front suspension 114 being attached to the steering shaft by a lower bracket (not shown). Front suspension 114 supports front wheel 110. The upper portion of the front wheel 110 is covered by a front fender 115, and the front fender 115 is mounted to the front suspension 114 at the end of the steering shaft. Handlebar assembly 108 is fixed to an upper bracket (not shown) and is rotatable in two directions to steer motor vehicle 100. A headlight 109, a visor (not shown), and an instrument panel (not shown) are provided at an upper portion of the head pipe 111. The down tube may be located in front of the IC engine 101 and extend obliquely downward from the head pipe 111. The main pipe 112 is located above the IC engine 101, and extends rearward from the head pipe 111. The IC engine 101 is mounted on the front through a down tube, and the rear of the IC engine 101 is connected to the main pipe 112 at the rear.

In one embodiment, the fuel tank 121 is mounted on the horizontal portion of the main pipe 112. The seat rail is coupled to the main tube 112 and extends rearward to support the seat 106. A rear swing arm (not shown) is connected to the frame assembly 105 to swing vertically, and a rear wheel 103 is connected to a rear end of the rear swing arm. Typically, the rear swing arm is supported by a single rear suspension or two suspensions 11 (as shown in the present embodiment) disposed on either side of the motor vehicle 100. A tail light unit (not shown) is provided at the end of the motor vehicle behind the seat 106. The rear wheel 103 is arranged substantially below the seat 106 and is rotated by the driving force of the IC engine 101, which is transmitted from the IC engine 101 through a chain transmission mechanism (not shown). In another embodiment, a belt drive, a continuously variable transmission, or an automatic transmission may be used. Further, an electric motor may be provided to assist the IC engine 101 or to independently drive the motor vehicle 100 in conjunction with the IC engine. An exhaust system 102 is connected to the IC engine 101 for discharging exhaust gas generated by combustion of the air-fuel mixture. In one embodiment, at least a portion of exhaust system 102 extends toward one side of motor vehicle 100 and is disposed adjacent rear wheel 103 (a portion of exhaust system 102 is disposed adjacent rear wheel 103, shown schematically in phantom).

Fig. 2 depicts a right side view of an IC engine 101 provided with an exhaust system 102 according to an embodiment of the present subject matter. The IC engine 101 includes a cylinder head assembly 210, the cylinder head assembly 210 having a cylinder head 203 and a cylinder head cover 202 mounted on top of the cylinder head 203. In one embodiment, the internal combustion engine 101 is a single cylinder engine. More specifically, in one embodiment, the internal combustion engine 101 is a four-stroke internal combustion engine 101. In other alternative embodiments, the internal combustion engine 101 may include more than one cylinder head, such as a plurality of cylinders. In one embodiment, the cylinder head 203 of the present subject matter includes one or more ports (not shown in this figure). For example, an exhaust port (not shown in the figure) of the internal combustion engine 101 is capable of discharging/discharging exhaust gas generated by combustion of an air-fuel mixture that is burned inside a combustion chamber (not shown) of the internal combustion engine 101. The gas discharged from the exhaust port is delivered through an exhaust pipe 215 of the exhaust system 102 of the internal combustion engine 101. In one embodiment, the exhaust pipe 215 includes an inlet opening 201 connected to an exhaust port (not shown in this figure) of the internal combustion engine 101 for smooth travel of the exiting exhaust gases. In one embodiment, the exhaust pipe 215 is connected to the cylinder head 203 by a flange member (not shown).

In one embodiment, cylinder head 203 of internal combustion engine 101 is mounted on top of cylinder block 204. The cylinder block 204 is supported by the crankcase 20. The cylinder head 203 and the cylinder block 204 define a combustion chamber (not shown) and a piston (not shown), and the piston is slidable in the combustion chamber, thereby achieving a four-stroke. In one embodiment, the exhaust duct 215 of the present subject matter includes a first bend 208 adjacent the inlet opening 201 and a second bend 209 further from the first bend 208. The distance between the first curve 208 and the second curve 209 depends on one or more parameters including the diameter of the wheel(s), the track width, the ground clearance of the second curve from the road/ground surface, etc. In one embodiment, engine 101 includes at least one spark plug (not shown). In one embodiment, the vehicle 100 is a saddle type vehicle. In another embodiment, the vehicle 100 is a straddle-type vehicle. The diameter of the wheels and the layout of the vehicle vary according to the type of vehicle described above and other types of vehicles.

In one embodiment, air-fuel supply 220 is connected to air intake 206 for regulating the supply of air and fuel. The air-fuel supply may be a carburetor, a combination throttle body and fuel injector, an electronic carburetor, or the like. In one embodiment, the cylinder head assembly 210 may include more than one exhaust port 205. In one embodiment, the cylinder head assembly 210 of the present subject matter has at least one intake port 206 that allows an air-fuel mixture to enter a combustion chamber (not shown). In one embodiment, the cylinder head assembly 210 includes at least one exhaust port 205 disposed on the other side of the intake port 206. In the illustrated embodiment, the intake port 206 is disposed on a rearward facing side of the cylinder head 203, and the exhaust port 205 is disposed on a forward facing side of the cylinder head 203. In other embodiments, the exhaust port 205 may be disposed on a rearward facing side or a downward facing side of the cylinder head, while the intake port is disposed substantially opposite the exhaust port.

In one embodiment, the exhaust pipe 215 includes at least one catalytic converter unit optimally disposed at a predetermined distance from the exhaust port 205 of the cylinder head 203. In one embodiment, the catalytic converter unit is arranged between the first bend 208 and the second bend 209 of the exhaust line 215. In one embodiment, at least one catalytic converter unit is a pre-catalytic converter or an auxiliary catalytic converter disposed upstream of a main catalytic converter (not shown) in the exhaust system of the present subject matter. In an alternative embodiment, a main catalytic converter (not shown) is disposed within the noise reducer 225 of the exhaust system 102 of the present subject matter. In one embodiment, the closer the catalytic converter unit is to the exhaust port, the higher the efficiency of the catalytic converter unit.

In one embodiment, exhaust pipe 215 includes an outlet portion 211 connected to a noise processing unit 225. The outlet 211 may extend into at least a portion of the noise processing unit 225. Further, the sealing member 204 is provided as a seal between the outlet portion 211 and the noise treatment unit 225 to eliminate any possibility of exhaust gas leakage into the atmosphere. In one embodiment, sealing member 204 is disposed annularly covering at least a portion of noise handling unit 225 and outlet portion 211. The sealing member 204 is preferably welded. Noise processing unit 225 extends substantially in the backward direction from outlet portion 211. As shown in fig. 1, in one embodiment, the noise processing unit 225 will be disposed adjacent at least a portion of the rear wheel 103 and under a rear seat pedal (not shown) of the motor vehicle 100.

Fig. 3 (a) shows a schematic diagram of a noise processing unit 225 according to an embodiment of the present subject matter. Noise treatment unit 225 is a portion of exhaust system 102 configured to exhaust gases generated during combustion of the air-fuel mixture and configured to reduce/attenuate noise generated during exhaust gas release prior to discharging exhaust gases released from the IC engine into the atmosphere.

The noise processing unit 225 includes a housing 360 (schematically shown in dashed lines) and a plurality of chambers (expansion chambers) formed by a plurality of baffles disposed within the noise processing unit 225. In the described embodiment, a plurality of first chambers, one or more second chambers, and one or more intermediate chambers are provided. In the depicted embodiment, two

first chambers

301, 302 are provided, and the outlet portion 211 of the exhaust pipe 215 is connected such that its downstream extension (365) opens into one of the two

first chambers

301, 302. Outlet portion 211 is provided with an extension 365, and extension 365 may be a solid tube or a perforated tube. Further, an intermediate chamber 311 is provided, and the intermediate chamber 311 is formed adjacent to at least one of the

first chambers

301, 302. A second chamber 321 is arranged behind the plurality of

first chambers

301, 302. In one embodiment, the second chamber 321 is disposed at a downstream portion of the noise processing unit 225. The first chamber 301 is formed by a first baffle 331 (between the first baffle and the upstream housing of the noise treatment unit 225), and the intermediate chamber 311 is formed between the first baffle 331 and a second baffle 332. The first chamber 302 disposed after the intermediate chamber 311 is formed between the second and

third baffles

332, 333. Hereinafter, the first chamber 301 is referred to as a primary first chamber, and the first chamber 302 is referred to as a secondary first chamber. In the current embodiment, the intermediate chamber 311 is physically disposed between the primary first chamber 301 and the secondary first chamber 302, or in general, the intermediate chamber 311 is selectively disposed between the plurality of

first chambers

301, 302. Further, a second chamber 321 is formed between the third baffle 333 and the end baffle 335.

In one embodiment, the volume of the intermediate chamber 311 (or the cumulative volume of the intermediate chambers, in the case of more than one intermediate chamber) is substantially less than the cumulative volume of the

first chambers

301, 302. The volume of the intermediate chamber 311 is also substantially less than the volume (or cumulative volume) of the second chamber 321. The exhaust EG entering the noise treatment unit 225 travels through the

first compartments

301, 302, then to the intermediate compartment 311, and then to the second compartment 321. The plurality of

chambers

301, 302, 311, 321 are configured to effectively reduce the momentum of the exhaust gas entering the muffler 235. In one embodiment, an intermediate chamber 311 of smaller volume disposed between the primary first chamber 301 and the secondary first chamber 302 is selectively bypassed as it travels therethrough, and exhaust gas enters the intermediate chamber 311 after flowing through all of the

first chambers

301, 302. The flow of exhaust gas in the noise treatment unit 225 will be discussed in the following description. In one embodiment, the

first chambers

301, 302 are configured to house additional catalytic converter units (not shown). The additional catalytic converter unit may serve as a primary catalytic converter or a secondary catalytic converter unit. Since the

first chambers

301, 302 are provided with a larger volume, the noise handling unit may even accommodate a larger primary converter here.

Fig. 3 (b) shows a schematic cross-sectional view of a noise processing unit 225 according to an embodiment of the present subject matter. The outlet portion 211 extending into the noise treatment unit 225 is provided with an extension 366, and the extension 366 is provided with a plurality of perforations configured to diffuse the exhaust EG entering the noise treatment unit 225. The diffused exhaust gas expands in the primary first chamber 301, thereby undergoing a reduction in momentum and producing a reduced-energy exhaust gas EG1. For example, in one embodiment, the chamber and the baffle, separated by the baffle, are assumed to have infinite impedance. The energy of the exhaust gas is reduced because heat dissipation (by conduction or convection) and expansion in the first chamber causes a reduction in momentum.

Further, a first connector 341 connects the primary first chamber 301 and the secondary first chamber 302. The term "connector" may include any device for transferring exhaust gas from one chamber to another. In one embodiment, similar to the described embodiments, the connector is a cylindrical member. The first connector 341 is disposed atbase:Sub>A position offset from the axisbase:Sub>A-base:Sub>A' of the noise processing unit 225 and the extension 365 to avoid the exhaust gas EG from directly entering the first connector 341 and to enable entry after expansion. The first connector 341 passes through the intermediate chamber 311, bypassing any exhaust gas flow from the primary first chamber 301 into the intermediate chamber 311. The first connector 341 passes through and is supported by the first barrier 331 and the second barrier 332. After reaching the secondary first chamber 302, the exhaust gas EG1 undergoes further expansion due to the larger volume of the secondary first chamber 302. In one embodiment, the secondary first chamber 302 is provided with a larger volume than the primary first chamber 301. The exhaust gas EG1 in the secondary expansion chamber 302 undergoes a further reduction in momentum, in particular due to the change in flow direction, resulting in a reduced energy exhaust gas EG2. In the secondary first chamber 302 of the current embodiment, the exhaust gas is guided to flow in a direction opposite to the direction in which it enters the noise treatment unit 225.

The noise treatment unit 225 is provided with a second connector 342 for connecting the secondary first chamber 302 to the intermediate chamber 311. The second connector 342 and the first connector 341 are provided at positions offset from the axisbase:Sub>A-base:Sub>A' of the noise processing unit 225 for achieving optimum packaging. The exhaust gas EG2 entering the intermediate chamber 311 has passed through the two large expansion chambers, and the intermediate chamber 311 having a smaller volume is configured to attenuate any high frequency waves of the exhaust gas, thereby generating the exhaust gas EG3 having further reduced energy. Subsequently, the exhaust gas EG3 undergoes a change in flow direction due to the third connector 343 connecting the intermediate chamber 311 and the second chamber 321, which is physically disposed after the secondary first chamber 302. The third connector 343 is supported by the second and

third baffles

332 and 343. The exhaust flow entering the second chamber 321 redirects the exhaust gas into the original flow direction.

The third connector 343 bypasses the secondary first chamber 302 thereby enabling gas to enter the second chamber 321 to attenuate any remaining higher frequency waves, thereby creating exhaust EG4 with further attenuation of noise. In one embodiment, third connector 343, second connector 342, and first connector 341 are disposed at positions offset from axisbase:Sub>A-base:Sub>A' of noise processing unit 225. This enables the

connectors

341, 342, 343 to be efficiently or optimally packaged on the second bezel 332. The second chamber 321 is provided with a discharge pipe 345 configured to discharge exhaust EG5 from the exhaust system 102 into the atmosphere. In one embodiment, exhaust gas outlet pipe 345 is provided with perforations for eventual diffusion of the exhaust gas. As a result, the exhaust gas EG5 leaving the noise treatment unit 225 is attenuated at substantially all frequencies, as shown by curve B of fig. 4. Curve B represents an exemplary graph plotted for noise attenuation across different frequencies according to embodiments of the present subject matter. It can be seen that curve B does not include any sudden surges or sudden rises and falls and relatively significant attenuation of noise across different frequencies.

Noise treatment unit 225 includes an intermediate chamber 311 with

baffles

331, 332 substantially closer together and disposed at substantially the middle of noise treatment unit 225, thereby providing the necessary structural rigidity at the middle to support the entire noise treatment unit 225. In one embodiment, the middle portion is a portion of the noise processing unit 225 that forms 50% of its middle region. In one embodiment, the mounting member 350 is disposed adjacent to the intermediate chamber 311. Therefore, during welding of the mounting member 350 to the housing 360, the total surface area in this area is greater due to the presence of the

baffles

331, 332, thereby reducing the effect of heat on the noise processing unit 225. Thus, any adverse effect on the material properties of the noise processing unit is minimal, making the structure rigid. The noise processing unit may be installed using a single installation member 350. However, in another embodiment, more than one mounting member may be used, if desired. As shown in fig. 3 (b), the

chambers

301, 302, 311, 321 are disposed adjacent to each other along the axisbase:Sub>A-base:Sub>A' of the noise processing unit 225 without increasing the width of the noise processing unit 225 (the overall cross-sectional area, and particularly the overall cross-sectional area in the vertical direction when viewed from the side, is not increased) so as to be mounted onbase:Sub>A motor vehicle havingbase:Sub>A small track width, such asbase:Sub>A track width in the range of 1200 to 1400 mm. Further, the noise processing unit 225 will not affect the compact layout and the desired position of the rear seat pedal, thereby avoiding any layout or design changes.

Fig. 3 (c) depicts another cross-sectional perspective view of the noise processing unit 225 according to an embodiment of the present subject matter. Fig. 3 (d) shows an enlarged view of a portion of the noise processing unit 225 according to an embodiment of the present subject matter, as shown in fig. 3 (c). The exhaust gas initially flows into the larger

first chamber

301, 302, which causes the exhaust gas entering at high velocity to expand and initially dampen certain frequency waves. Further, the

baffles

331, 332, 333 are configured to provide destructive interference to counteract undesirable sound frequencies generated during combustion. Further, the

first chambers

301, 302, which have the intermediate chamber 311 selectively disposed between the

first chambers

301, 302, provide a longer traveling path for the exhaust gas within the

first chambers

301, 302 and pass through the first connector 341 in a longer length, thereby obtaining a longer flow path, thereby enabling energy absorption through heat dissipation and sound attenuation. The longer flow path noise processing unit 225 eliminates unwanted noise/sound. Further, the intermediate chamber 331, which is selectively physically arranged between the

first chambers

301, 302, and with the flow entering the intermediate chamber 311 after passing through all the

first chambers

301, 302, enables at least two reversals of the flow direction, thereby further slowing down the exhaust gases and enabling higher transmission losses, resulting in a noise reduction. The change in surface area provides resistance to the flow of exhaust gas and the exhaust gas reflects a portion of its intensity in the form of sound waves in a direction opposite to its direction of travel, i.e., produces sound waves of relative phase. The reflected relative phase sound waves cancel the initial sound waves of the exhaust gas, thereby reducing the exhaust sound to a desired exhaust sound. In one embodiment, to further achieve diffusion of the exhaust gases, the

connectors

341, 342, 343 may be provided with perforations which, in combination with the configuration of the muffler, achieve an effective attenuation of the noise.

The muffler of the exhaust system with the muffler is designed such that it takes up minimal space on the motor vehicle, thereby eliminating the need for a modified layout. The number of expansion chambers can be increased or decreased as desired. The exhaust system may be used in any type of vehicle including two-or three-wheeled motor vehicles or even in compact layout multi-wheeled vehicles.

While certain features of the claimed subject matter have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of claimed subject matter.

List of reference numbers:

100. vehicle with a steering wheel

101 IC engine

102. Exhaust system

103. Rear wheel

105. Frame assembly

106. Seat with a detachable cover

108. Handle assembly

109. Head lamp

110. Front wheel

111. Head pipe

112. Main pipe

114. Front suspension

115. Front mudguard

116. Chain transmission mechanism

11. Rear suspension

121. Fuel tank

201. Inlet section

202. Cylinder head cover

203. Cylinder cover

204. Sealing member

205. Exhaust port

206. Air inlet

207. Crankcase

208. First curve

209. Second bend

210. Cylinder head assembly

211. Outlet section

215. Exhaust pipe

220. Air-fuel supply device

301. Primary first chamber

302. Secondary first chamber

311. Intermediate chamber

321. Second chamber

331. First baffle plate

332. Second baffle

333. Third baffle

335. End baffle

341. First connector

342. Second connector

343. Third connector

345. Discharge pipe

350. Mounting member

360. Outer cover

365. Extension part

366. Extension part (perforation)

EG/EG1/EG2/EG3/EG/EG4/EG5 off-gas

The claims (modification according to treaty clause 19)

1. A noise processing unit (225) for a motor vehicle (100), the noise processing unit (225) comprising:

a plurality of first chambers (301, 302), the plurality of first chambers (301, 302) comprising a primary first chamber (301) and a secondary first chamber (302),

wherein the primary first chamber (301) is configured to receive exhaust gas from an internal combustion engine (101);

one or more second compartments (321), the one or more second compartments (321) being connected to the secondary first compartment (302); and

one or more intermediate chambers (311),

the one or more intermediate chambers (311) are disposed between the primary first chamber (301) and the secondary first chamber (302) of the plurality of first chambers (301, 302),

wherein the noise treatment unit (225) is configured to direct exhaust gas to flow from the primary first chamber (301) to the secondary first chamber (302) bypassing the one or more intermediate chambers (311),

wherein the primary second chamber (302) is configured to direct exhaust gas flow to the one or more intermediate chambers (311), and

wherein the one or more intermediate chambers (311) are configured to direct the flow of exhaust gas to the one or more second chambers (321).

2. A noise treatment unit (225) for the motor vehicle (100) as claimed in claim 1, wherein the one or more intermediate chambers (311) comprise a cumulative volume that is smaller than a cumulative volume of any of the plurality of first chambers (301, 302) and the one or more second chambers (321), and wherein the one or more second chambers (321) are disposed at a downstream portion of the noise treatment unit (225).

3. The noise treatment unit (225) for the motor vehicle (100) of claim 1, wherein the one or more intermediate chambers (311) are configured to change a flow direction of exhaust gas in two or more directions.

4. The noise-treatment unit (225) for the motor vehicle (100) according to claim 1, wherein the plurality of first chambers (301, 302), the one or more intermediate chambers (311) and the one or more second chambers (321) are arranged adjacent along an axis (base:Sub>A-base:Sub>A') of the noise-treatment unit (225).

5. A noise-treatment unit (225) for a motor vehicle (100) according to claim 1, wherein the one or more intermediate chambers (311) comprise at least one intermediate chamber (311) arranged substantially at the middle of the noise-treatment unit (225), and the at least one intermediate chamber (311) is formed by a first baffle (331) and a second baffle (332) arranged in proximity to each other.

6. The noise-treatment unit (225) for the motor vehicle (100) as claimed in claim 1, wherein the noise-treatment unit (225) comprises a mounting member (350), and the mounting member (350) is fixed to a housing (360) of the noise-treatment unit (225) at a portion near the intermediate chamber (311).

7. The noise handling unit (225) for the motor vehicle (100) of claim 1, wherein the primary first chamber (301) and the secondary first chamber (302) are connected by a first connector (341) bypassing the intermediate chamber (311).

8. A noise treatment unit (225) for the motor vehicle (100) according to claim 1, wherein the noise treatment unit (225) comprises a second connector (342) connecting the secondary first chamber (320) to the intermediate chamber (311), and a third connector (343) passes connecting the intermediate chamber (311) to one of the one or more second chambers (321) through a third baffle (333) forming one of the one or more second chambers (321).

9. The noise processing unit (225) for the motor vehicle (100) according to claim 7, wherein the noise processing unit (225) comprises at least two of the first connector (341), the second connector (342) and the third connector (343) arranged atbase:Sub>A position offset from an axis (A-A') of the noise processing unit (225).

10. The noise handling unit (225) for the motor vehicle (100) of claim 1, the motor vehicle (102) comprising a track width ranging between 1200 millimeters to 1400 millimeters.

11. A noise treatment unit (225) for the motor vehicle (100) as claimed in claim 1, the exhaust system (102) comprising an exhaust pipe (215) having an outlet portion (211), the outlet portion (211) comprising an extension (366) extending into one of the plurality of first chambers (301, 302), and the one or more second chambers (321) comprising an exhaust pipe (345), and wherein at least one of the outlet portion (211) and the exhaust pipe (345) is provided with perforations.

12. A method of treating exhaust gas with a noise treatment unit (225), the method comprising the steps of:

passing the exhaust gas through a plurality of first chambers (301, 302) of the noise treatment unit (225), the plurality of first chambers (301, 302) comprising a primary first chamber (301) and a secondary first chamber (302);

passing the exhaust gas through one or more intermediate chambers (311) selectively disposed between the primary first chamber (301) and the secondary first chamber (302) of the plurality of first chambers (301, 302); and

directing the exhaust gas through the one or more second chambers (321).

Claims

1. A noise treatment unit (225) for a motor vehicle (100), the noise treatment unit (225) forming part of an exhaust system (102), part of the exhaust system (102) being functionally connected to an internal combustion engine (101) of the motor vehicle (100), the noise treatment unit (225) comprising:

a plurality of first chambers (301, 302);

one or more second chambers (321); and

one or more intermediate chambers (311), the one or more intermediate chambers (311) being selectively disposed between the plurality of first chambers (301, 302), an

The noise treatment unit (225) is configured to direct exhaust gas flow through the plurality of first chambers (301, 302), then through the one or more intermediate chambers (311), and then through the one or more second chambers (321).

2. The noise processing unit (225) for the motor vehicle (100) of claim 1, wherein the one or more intermediate chambers (311) comprise a cumulative volume that is less than a cumulative volume of any of the plurality of first chambers (301, 302) and the one or more second chambers (321), and wherein the one or more second chambers (321) are disposed at a downstream portion of the noise processing unit (225).

6. A noise-treatment unit (225) for the motor vehicle (100) according to claim 1, wherein the noise-treatment unit (225) comprises a mounting member (350), and the mounting member (350) is fixed to a housing (360) of the noise-treatment unit (225) at a portion near the intermediate chamber (311).

7. The noise processing unit (225) for the motor vehicle (100) of claim 1, wherein the plurality of first chambers (301, 302) includes a primary first chamber (301) and a secondary first chamber (302), and a first connector (341) connects the primary first chamber (301) and the secondary first chamber (302) bypassing the intermediate chamber (311).

8. The noise-treatment unit (225) for the motor vehicle (100) according to claim 1 or 6, wherein the noise-treatment unit (225) comprises a second connector (342) connecting the secondary first chamber (320) to the intermediate chamber (311), and a third connector (343) passes connecting the intermediate chamber (311) to one of the one or more second chambers (321) through a third baffle (333) forming one of the one or more second chambers (321).

9. A noise handling unit (225) forbase:Sub>A motor vehicle (100) according to claim 7, wherein the noise handling unit (225) comprises at least two of the first connector (341), the second connector (342) and the third connector (343) arranged at positions offset from an axis (A-A') of the noise handling unit (225).

passing the exhaust gas through a plurality of first chambers (301, 302) of the noise treatment unit (225); passing the exhaust gas through one or more intermediate chambers (311) selectively disposed between the plurality of first chambers (301, 302); and

directing the exhaust gas through the one or more second chambers (321).