Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N1/00—Silencing apparatus characterised by method of silencing
  • F01N1/08—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling
  • F01N1/084—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling the exhaust gases flowing through the silencer two or more times longitudinally in opposite directions, e.g. using parallel or concentric tubes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N2470/00—Structure or shape of exhaust gas passages, pipes or tubes
  • F01N2470/08—Exhaust gas passages being formed between the walls of an outer shell and an inner chamber
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N2490/00—Structure, disposition or shape of gas-chambers
  • F01N2490/02—Two or more expansion chambers in series connected by means of tubes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N2490/00—Structure, disposition or shape of gas-chambers
  • F01N2490/15—Plurality of resonance or dead chambers
  • F01N2490/155—Plurality of resonance or dead chambers being disposed one after the other in flow direction
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N2490/00—Structure, disposition or shape of gas-chambers
  • F01N2490/18—Dimensional characteristics of gas chambers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
  • F01N2590/00—Exhaust or silencing apparatus adapted to particular use, e.g. for military applications, airplanes, submarines
  • F01N2590/04—Exhaust or silencing apparatus adapted to particular use, e.g. for military applications, airplanes, submarines for motorcycles

Definitions

• the present subject matter relates to a noise processing unit for a motor vehicle and more particularly but not exclusively to the noise processing unit for two-wheeled or three-wheeled motor vehicles.
• a motor vehicle powered by an internal combustion (IC) engine
• an exhaust system which is connected to an exhaust port of the IC engine.
• the exhaust system is used for expelling exhaust gases, produced due to the combustion of air-fuel mixture in one or more combustion chambers of the IC engine of the motor vehicle, into the atmosphere as the exhaust gases comprise carbon monoxide, hydrocarbons, nitrous oxides etc.
• the exhaust system in addition to being used for treating the exhaust gases, is also used for attenuating noise produced due to the combustion process.
• FIG. 1 illustrates a left-side view of an exemplary motor vehicle, in accordance with an embodiment of the present subject matter.
• FIG. 2 depicts a right-side view of an exemplary internal combustion engine with an exhaust system, in accordance with an embodiment of the present subject matter.
• Fig. 3 (a) illustrates a schematic view of a noise processing unit, in accordance with an embodiment of the present subject matter.
• Fig. 3 (b) illustrates a schematic sectional view of the noise processing unit, in accordance with an embodiment of the present subject matter.
• Fig. 3 (c) depicts another sectional view of the noise processing unit, in accordance with an embodiment of the present subject matter.
• FIG. 3 (d) illustrates an enlarged view of a portion of the noise processing unit, in accordance with an embodiment of the present subject matter as depicted in Fig. 3 (c).
• motor vehicles employ methods such as increasing a surface area/ volume of a portion of the exhaust system where exhaust gases expand, typically, inside a muffler.
• multiple tail pipes or split type exhaust system are used. All these methods increase the overall size of the exhaust system including the muffler.
• Such solutions are implemented in large capacity motor vehicles like four-wheeled motor vehicles or multi-wheeled motor vehicles having more than four wheels.
• Such motor vehicles have larger bodies and have scope for accommodating longer and larger even split type exhaust systems.
• Attempts have been made to adapt similar solutions in two-wheeled or three-wheeled motor vehicles with large capacity, which typically have a larger vehicle area or with a longer wheel base.
• such solutions cannot be implemented in smaller capacity commuter vehicles with compact vehicle layout or with relatively smaller wheel base.
• the aforementioned solutions add up to manufacturing cost of the vehicle, making it impractical to be implemented in low-cost smaller capacity motor vehicles.
• the two-wheeled motor vehicle typically, has a naked appearance, at least a rearward portion of the motor vehicle.
• various critical components like the IC engine are compactly packaged between the two wheels.
• Some two-wheeled motor vehicle may even have a storage space for carrying loads or goods that requires additional utility space on the vehicle which cannot be compromised or reduced.
• the exhaust system is routed carefully keeping it away from the critical components of the motor vehicle and away from rider, typically being disposed towards a rearward portion of the vehicle, to limit dissipation of heat towards the critical components or the rider and / or pillion.
• a control valve is provided within the muffler in order to direct air through various pipes or chambers.
• valves require additional volume in the muffler along with such plural passages and also, requiring actuators, mechanical or electronic, to control the valve thereby increasing cost of the system.
• Creation of additional volume on the already compact motor vehicle increases size of the exhaust system, which may result in interfering with other components of the motor vehicle or with pillion rider. Also, increasing size of the exhaust system creates a challenge of appearance and disproportionate appearance, which is undesired.
• Curve A depicted in Fig. 4, illustrates an exemplary attenuation curve at various frequencies for a typical small capacity motor vehicle.
• the noise attenuation is almost negligible. This makes an exhaust note very disturbing due to improper attenuation making it noisy for the rider and for passersby.
• exhaust system or the muffler in the two-wheeled or three wheeled motor vehicles have one or two mounting portions thereof thereby leading to a major challenge of mounting such complex exhaust systems.
• the mounting portion like a mounting bracket acts as a connecting member between the muffler and a frame assembly or chassis of the motor vehicle.
• welding temperatures typically shoot up to 1000°C thereby affecting mechanical property of the heat affected zone resulting in undesirable failure eventually, rendering the damaged or deteriorated exhaust system, a noisy one.
• the exhaust system should be compact in order to implemented even in a motor vehicle with a smaller wheel base. Further, the exhaust system should be cost-effective and should easy to install with rigid mounting without any modification of existing frame assembly or chassis.
• the exhaust system as per the present invention comprises a noise processing unit with a compact configuration to be accommodated on a compact motor vehicle.
• the noise processing unit comprises multiple chambers configured to effectively attenuate noise across various frequencies without occupying much space.
• the noise processing unit comprises plurality of first chambers, one or more second chambers and one or more intermediate chambers.
• the plurality of first chambers substantially form upstream chambers.
• the one or more intermediate chambers are selectively disposed physically between the plurality of first chambers.
• the one or more second chambers form the downstream chambers.
• the noise processing unit is configured to direct exhaust gases to flow through the plurality of first chambers, subsequently through the one or more intermediate chambers and through the one or more second chambers for effective noise attenuation across a large frequency range.
• the exhaust gases pass through a substantial number of first chambers and then passes through the intermediate chambers.
• the noise reduction unit or noise processing unit can be configured such that the exhaust gas is made to pass through both the first chambers and then through the intermediate chamber(s).
• one or more intermediate chambers comprises of cumulative volume which is less than a cumulative volume any one of said plurality of first chambers, plus said one or more second chambers.
• the first chambers with larger volume enables expansion of exhaust gases which enter the noise processing unit with higher velocity.
• the larger first chambers enable reduction of energy and correspondingly noise due to effective expansion.
• the intermediate chambers with smaller volume is configured to act upon large frequencies of waves that get attenuated thereat due to a substantial change in area and volume.
• the chambers are configured to create internally reflecting opposite-phase sound waves of various frequencies, which get selectively cancelled out across the chambers resulting in desired sound effect.
• the one or more intermediate chambers are selectively disposed between the plurality of first chambers in a predetermined layout. Said one or more intermediate chambers are configured to change direction of flow of exhaust gases in two or more directions. This increases the travel path of the exhaust gases leading to enhanced dissipation of the heat energy.
• the plurality of first chambers, the one or more intermediate chambers and the one or more second chambers are disposed adjoiningly along an axis of the noise processing unit. Since each chamber is disposed adjacent to another chamber along the axis any expansion of size, say in vertical direction, is avoided thereby not affecting current position of a pillion foot-rest and position of other critical components. Thus, the present subject matter achieves effective noise attenuation by even creating at least two directional changes of flow of exhaust gases by substantially retaining the cross- sectional area of the unit.
• the one or more intermediate chambers of the noise processing unit comprises at least one intermediate chamber disposed substantially at a mid-portion of the noise processing unit.
• the at least one intermediate chamber is formed by a first baffle plate and a second baffle plate, and the baffle plates are to be disposed in proximity to each other to form the smaller volume and the baffle plates at the mid-portion enable retention of structural integrity during welding of a mounting member or the like due to large surface area at that region. Further, configuration of the noise processing unit eliminates need for providing perforations on the baffle plate itself which would have affected the structural integrity of the baffle plates.
• the noise processing unit comprises a mounting member and the mounting member is secured to an outer casing of the noise processing unit at a portion in proximity to the intermediate chamber. Even though welding happens on the outer casing, the baffle plates disposed in proximity provide additional area to accommodate higher heat during welding or the like.
• the noise processing unit comprises plurality of connectors, configured to bypass an immediately disposed chamber, to provide a longer flow path and also enable a change in direction of flow by bypassing an immediate chamber.
• the connectors are provided with optimal length for establishing connection between chambers without need for extension of connectors along entire length of the noise processing unit.
• At least two connectors, passing through a baffle plate, are disposed at an offset from an axis of the noise processing unit for optimal accommodation of components without occupying large space.
• three connectors are accommodated on the baffle plate and three connectors are disposed at an offset from the axis of the noise processing unit, which is typically taken at a center of the noise processing unit.
• the noise processing unit is configured for a compact vehicle comprising a wheel base in range of 1200 - 1400 millimeters.
• the exhaust system comprises an exhaust pipe with an outlet portion.
• the outlet portion comprises an extended portion that at least partially extends into one of the plurality of first chambers.
• the one or more second chambers comprises an out-pipe for expelling gases into atmosphere.
• the at least one of the outlet portion and the out-pipe is provided with perforations that are configured to diffuse exhaust gases during entry and during exit from the noise processing unit.
• the intermediate chamber is configured to attenuate high frequency waves in exhaust gases, which are greater than 4000 Hz that are unpleasant to human ear.
• the second chamber with a cumulative volume greater than the first chambers is configured to attenuate frequency waves in range of 1500 Hz to 3000 Hz, which typically create a metallic sound, with at least two directional changes or flow reversals.
• the exhaust gases expelled from the noise processing unit are pleasant to rider and passers by creating a requisite exhaust noise that is desired.
• the exhaust system may be implemented in any two-wheeled vehicle or a three-wheeled motor vehicle.
• Arrows wherever provided on top right comer of the figure represent direction with respect to motor vehicle.
• Arrow F represents forward direction
• arrow R represents rearward direction
• arrow UW represents upward direction
• arrow DW represents downward direction.
• Fig. 1 illustrates a left-side view of an exemplary motor vehicle 100, in accordance with an embodiment of the present subject matter.
• the motor vehicle 100 comprises of a frame assembly 105 acting as a structural member of the motor vehicle 100.
• the frame assembly 105 comprises a head tube 111, a main tube 105 (schematically shown with dotted line) extending rearwardly downward from the head tube 111.
• the motor vehicle comprises a front wheel 110, a rear wheel 103, a fuel tank 121 and seat 106.
• the frame assembly 105 includes a main tube 112, a down tube (not shown), and one or more seat rails (not shown) extending rearward from the main tube 112.
• the head pipe 111 supports a steering shaft (not shown) and a front suspension 114 (only one visible) that is attached to the steering shaft through a lower bracket (not shown).
• the front suspension 114 supports the front wheel 110.
• the upper portion of the front wheel 110 is covered by a front fender 115 mounted to the front suspension 114 at the end of the steering shaft.
• a handlebar assembly 108 is fixed to upper bracket (not shown) and can rotate in both directions for maneuvering the motor vehicle 100.
• a head light 109, a visor guard (not shown) and instrument cluster (not shown) is arranged on an upper portion of the head pipe 111.
• the down tube may be located in front of the IC engine 101 and extends slantingly downward from head pipe 111.
• the main tube 112 is located above the IC engine 101 and extends rearward from head pipe 111.
• the IC engine 101 is mounted at the front by the down tube and rear of the IC engine 101 at the rear portion is connected to the main tube 112.
• the fuel tank 121 is mounted on a horizontal portion of the main tube 112.
• Seat rails are joined to main tube 112 and extend 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 rear end of the rear swing arm.
• the rear swing arm is supported by a mono rear suspension or two suspensions 11 (as illustrated in the present embodiment) disposed on either side of the motor vehicle 100.
• a tail light unit (not shown) is disposed at the end of the motor vehicle at the rear of the seat 106.
• the rear wheel 103 is arranged substantially below the seat 106 and rotates by a driving force of the IC engine 101 transmitted through a chain drive (not shown) from the IC engine 101.
• a chain drive (not shown) from the IC engine 101.
• a belt drive, a continuously variable transmission or an automatic transmission may be used.
• an electric motor may be provided to assist the IC engine 101 or to independently drive the motor vehicle 100 in conjunction with an IC engine.
• An exhaust system 102 is connected to the IC engine 101 for expelling exhaust gases generated due to combustion of air-fuel mixture.
• At least a portion of the exhaust system 102 extends towards one lateral side of the motor vehicle 100 and is disposed adjacent to the rear wheel 103 (a portion of the exhaust system 102 disposed adjacent to the rear wheel 103 and is schematically shown in dotted line).
• Fig. 2 depicts a right-side view of the IC engine 101 provided with an exhaust system 102, in accordance with an embodiment of the present subject matter.
• the IC engine 101 comprises a cylinder head assembly 210 having a cylinder head 203 and a cylinder head cover 202 mounted atop the cylinder head 203.
• the internal combustion engine 101 is a single cylinder engine. More particularly, in one embodiment, the internal combustion engine 101 is a four-stroke internal combustion engine 101. In other alternative embodiment, the internal combustion engine 101 can include more than one cylinder head, say a plurality of cylinders.
• the cylinder head 203 of the present subject matter includes one or more ports (not shown in this figure).
• an exhaust port (not seen in this figure) of the internal combustion engine 101 enables exiting/expelling out the exhaust gases arising out of the combustion of the air-fuel mixture that occurs inside the combustion chamber (not shown) of the internal combustion engine 101.
• the gases exiting from the exhaust port are transported through an exhaust pipe 215 of the exhaust system 102 of the internal combustion engine 101.
• the exhaust pipe 215 includes an inlet opening 201 which is connected to the exhaust port (not seen in this figure) of the internal combustion engine 101 for enabling smooth travel of the exiting exhaust gases.
• the exhaust pipe 215 is connected to the cylinder head 203 through a flange member (not shown).
• the cylinder head 203 of the internal combustion engine 101 is mounted atop a cylinder block 204.
• the cylinder block 204 is supported by a crankcase 20.
• the cylinder head 203 and the cylinder block 204 define a combustion chamber (not shown) and a piston (not shown) which is slidable within the combustion chamber resulting in the four-strokes.
• the exhaust pipe 215 of the present subject matter includes a first bend 208 adjacent to the inlet opening 201 and a second bend 209 farther from the first bend 208.
• a distance between the first bend 208 and the second bend 209 depends on one or more parameters including a diameter of wheel(s), wheel base, ground clearance of the second bend from a road / ground surface etc.
• the engine 101 includes at least one spark plug (not shown).
• the vehicle 100 is a saddle-ride type vehicle. In another embodiment, the vehicle 100 is a step-through type vehicle. A diameter of wheel and a layout of the vehicle is subject to alter depending on the aforementioned type and other type of vehicles.
• an air-fuel supply device 220 is connected to intake port 206 for regulated supply of air and fuel.
• the air-fuel supply device can be a carburetor, a combination of throttle body and fuel-injector, an electronic carburetor or the like.
• the cylinder head assembly 210 can include more than one exhaust port 205.
• the cylinder head assembly 210 of the present subject matter has at least one intake port 206 that allows entry of air-fuel mixture into the combustion chamber (not shown).
• the cylinder head assembly 210 includes at least one exhaust port 205 disposed on the other side of the intake port 206.
• the intake port 206 is disposed on rearward facing side of the cylinder head 203 and the exhaust port 205 is disposed on a front facing side of the cylinder head 203.
• the exhaust port 205 can be disposed on a rear facing side or a downward facing side of the cylinder head and the intake port is disposed substantially opposite to the exhaust port.
• the exhaust pipe 215 includes at least one catalytic converter unit optimally disposed at a pre-determined distance from the exhaust port 205 of the cylinder head 203.
• the catalytic converter unit is disposed between the first bend 208 and the second bend 209 of the exhaust pipe 215.
• the at least one catalytic converter unit is a pre- catalytic converter or an auxiliary catalytic converter, which is provided upstream of a main catalytic converter (not shown) in the exhaust system of the present subject matter.
• the main catalytic converter (not shown) is disposed within a noise reduction device 225 of the exhaust system 102 of the present subject matter. In an embodiment, closer the catalytic converter unit to the exhaust port, higher is the efficiency of the catalytic converter unit.
• the exhaust pipe 215 comprises an outlet portion 211 that is connected to the noise processing unit 225.
• the outlet portion 211 may extend in to at least a portion of the noise processing unit 225.
• a sealing member 204 is provided to act as a seal between the outlet portion 211 and noise processing unit 225 to eliminate any leak of exhaust gases into atmosphere.
• the sealing member 204 is disposed to annularly cover at least a portion of the noise processing unit 225 and the outlet portion 211.
• the sealing member 204 is preferably welded.
• the noise processing unit 225 extends substantially in a rearward direction from the outlet portion 211. As depicted in Fig. 1, the noise processing unit 225, in one implementation, would be disposed adjacent to at least a portion of the rear wheel 103 and below a pillion foot-rest (not shown) of the motor vehicle 100.
• Fig. 3 (a) illustrates a schematic view of a noise processing unit 225, in accordance with an embodiment of the present subject matter.
• the noise processing unit 225 which is part of the exhaust system 102, is configured to expel exhaust gases produced during the combustion of air-fuel mixture and is configured to perform reduction/ attenuation of noise generated during release of the exhaust gases from the IC engine before expelling into the atmosphere.
• the noise processing unit 225 comprises an outer casing 360 (schematically shown in dotted lines) and a plurality of chambers (expansion chambers) that are formed by plurality of baffle plates disposed within the noise processing unit 225.
• plurality of first chamber(s), one or more second chamber(s) and one or more intermediate chamber(s) are provided.
• two first chambers 301, 302 are provided and the outlet portion 211 of the exhaust pipe 215 is connected such that its downstream extended portion (365) opens into one of the two first chamber 301, 302.
• the outlet portion 211 is provided with an extended portion 365 and the extended portion 365 may be a solid tube or a perforated tube.
• 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 provided subsequent to the plurality of the first chambers 301, 302.
• the second chambers 321 is disposed at a downstream portion of the noise processing unit 225.
• the first chamber 301 is formed by a first baffle plate 331 (between the first baffle plate and an upstream enclosure of the noise processing unit 225), the intermediate chamber 311 is formed between the first baffle plate 331 and a second baffle plate 332.
• the first chamber 302 disposed subsequent to the intermediate chamber 311 is formed between the second baffle plate 332 and a third baffle plate 333.
• 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.
• the intermediate chamber 311 is disposed physically between the primary-first chamber 301 and the secondary-first chamber 302 or generally referring, the intermediate chamber 311 is selectively disposed between plurality of first chambers 301, 302.
• the second chamber 321 is formed between the third baffle plate 333 and an end- baffle plate 335.
• a volume of the intermediate chamber 311 (or a cumulative volume of intermediate chambers in case of more than one intermediate chamber) is substantially smaller than a cumulative volume of the first chambers 301, 302.
• the volume of the intermediate chamber(s) 311 is also substantially smaller than a volume (or cumulative volume) of second chambers 321.
• the exhaust gases EG entering the noise processing unit 225 passes through the first chambers 301, 302, then to the intermediate chamber(s) 311 and then to the second chamber(s) 321.
• the plurality of chambers 301, 302, 311, 321 are configured to effectively reduce momentum of the exhaust gases entering the muffler 235.
• the intermediate chamber 311 with the lesser volume disposed between the primary-first chamber 301 and the secondary-first chamber 302 is selectively bypassed while travelling therethrough and the exhaust gases enter the intermediate chamber 311 after flowing through all the first chambers 301, 302.
• the flow of exhaust gases in the noise processing unit 225 is discussed in subsequent description.
• the first chamber 301, 302 are configured to accommodate an additional catalytic converter unit (not shown).
• the additional catalytic converter unit can act as a primary catalytic converter or a secondary catalytic converter unit.
• the noise processing unit can accommodate even a larger primary converter thereat.
• Fig. 3 (b) illustrates a schematic sectional view of a noise processing unit 225, in accordance with an embodiment of the present subject matter.
• the outlet portion 211 extending into the noise processing unit 225 is provided with an extended portion 366 which is provided with plurality of perforations, configured to diffuse exhaust gases EG entering the noise processing unit 225.
• the diffused exhaust gases expand in the primary-first chamber 301 thereby experiencing reduction in momentum and resulting in exhaust gases EG1 with reduced energy.
• the chambers that are separated by the baffle plates and the baffle plates are assumed to have infinite impedance, in one implementation.
• the reduction in energy of exhaust gases occurs due to dissipation of heat (by conduction or convention) in the first chamber and due to reduction of momentum due to expansion.
• a first connector 341 connects the primary-first chamber 301 and the secondary-first chamber 302.
• the term ‘connector’ may include any means for transferring exhaust gases from one chamber to another.
• the connector is a cylindrical member.
• the first connector 341 is disposed at an offset from an axis A-A’ of the noise processing unit 225 and from the extended portion 365 to avoid direct entry of exhaust gases EG into the first connector 341 and to enable entry after expansion.
• the first connector 341 passes through the intermediate chamber 311, bypassing flow of any exhaust gases into the intermediate chamber 311 from the primary- first chamber 301.
• the first connector 341 passes through the first baffle plate 331 and the second baffle plate 332 and is supported by them.
• the secondary-first chamber 302 is provided with a volume larger than the primary- first chamber 301.
• the exhaust gases EG1 in the secondary-expansion chamber 302 experience a further reduction in momentum, especially due to change in direction of flow resulting in exhaust gases EG2 with reduced energy.
• the exhaust gases are directed to flow in a direction opposite to a direction of entry of the exhaust gases into the noise processing unit 225.
• the noise processing 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 first connector 341 are disposed at an offset from an axis A-A’ of the noise processing unit 225 for optimal packaging.
• the exhaust gases EG2 entering the intermediate chamber 311 has already passed through two large expansion chambers and the intermediate chamber 311 with the smaller volume is configured to attenuate any high frequency waves of the exhaust gas resulting into exhaust gas EG3 with further reduced energy. Subsequently, the exhaust gases EG3 experiences a change in flow direction due to a third connector 343 connecting the intermediate chamber 311 and the second chamber 321, which is physically disposed subsequent to secondary-first chamber 302.
• the third connector 343 is supported by the second baffle plate 332 and the third baffle plate 343. Flow of the exhaust gases into the second chamber 321 causes the exhaust gases to realign into the original flow direction.
• the third connector 343 bypasses the secondary-first chamber 302 thereby enabling passage of gases into the second chamber 321 for attenuation of any remaining higher frequency waves thereby resulting in exhaust gases EG4 with further noise attenuation.
• the third connector 343, the second connector 342, and the first connector 341 are disposed at an offset from the axis A-A’ of the noise processing unit 225. This enables the connectors 341, 342, 343 to be efficiently or optimally packaged on the second baffle plate 332.
• the second chamber 321 is provided with an out-pipe 345 configured to expel the exhaust gases EG5 from the exhaust system 102 into the atmosphere.
• the exhaust out-pipe 345 is provided with perforation for a final diffusing of exhaust gases.
• the exhaust gases EG5 exiting the noise processing unit 225 have an attenuation substantially across all frequencies as depicted in Curve B of Fig. 4.
• the Curve B represents an exemplary graph plotted for noise attention across various frequencies, in accordance with an embodiment of the present subject matter. As can see, curve B does not comprise any sudden spikes or sudden rise and falls and a relatively substantial attenuation of noise across various frequencies.
• the noise processing unit 225 comprises the intermediate chamber 311, with the baffle plates 331, 332 that are substantially closer, and disposed at a substantial mid-portion of the noise processing unit 225 thereby providing requisite structural rigidity at the mid-portion to support the entire noise processing unit 225.
• the mid-portion is a portion of the noise processing unit 225 forming a 50% mid-region thereof.
• a mounting member 350 is disposed in proximity to the intermediate chamber 311. Thus, during welding of the mounting member 350 to the outer casing 360, a total surface area in that region is larger due to the presence of the baffle plates 331,
• the noise processing unit 225 can be mounted using a single mounted member 350. However, in another implementation, more than one mounting member may be used if required. As depicted in Fig. 3 (b), the chambers 301, 302, 311, 321 are disposed adjoining each other along an axis A- A’ of the noise processing unit 225 without increasing width of the noise processing unit 225 (overall cross-sectional area and especially in vertical direction, when viewed from side) so as to be mounted on motor vehicles having smaller wheel base say a wheelbase in the range of 1200 to 1400 millimeters. Further, the noise processing unit 225 would not be interfering with the compact layout and with required position of a pillion foot-rest thereby avoiding any layout or design change.
• FIG. 3 (c) depicts another sectional perspective view of the noise processing unit 225, in accordance with an embodiment of the present subject matter.
• Fig. 3 (d) illustrates an enlarged view of a portion of the noise processing unit 225, in accordance with an embodiment of the present subject matter as depicted in Fig. 3 (c).
• the exhaust gases flow initially into larger first chamber 301, 302 that enable expansion of exhaust gases which enter at high velocity and initially suppressing certain frequency waves.
• the first chambers 301, 302 with the intermediate chambers 311 selectively provided between the first chambers 301, 302 provide longer travel path for the exhaust gases within the first chambers 301, 302 and through the first connector 341 with longer length whereby longer flow path is obtained thereby enabling absorption of energy by dissipation of heat and attenuation of sound.
• the noise processing unit 225 with the lengthier flow path eliminates unwanted noise/ sound.
• the intermediate chamber 331 disposed selectively physically between the first chambers 301, 302 and with a flow entering the intermediate chamber 311 after passing through all the first chambers 301, 302 enables at least a double reversal of flow direction thereby further slowing down the exhaust gases and enabling higher transmission losses, which results in reduced noise.
• the change in the surface area provides a resistance to the flow of the exhaust gases, and the exhaust gases reflect a portion of their strength in the form of sound waves in a direction opposite to their travel direction, i.e., sound waves of an opposite phase are created.
• the reflected opposite-phase sound waves cancel out initial sound waves of the exhaust gases, thereby reducing the exhaust sound to a desired exhaust sound.
• the connector 341, 342, 343 can be provided with perforations that in conjunction with the configuration of the muffler enable effective attenuation of noise.
• the muffler of the exhaust system with the muffler is designed such that minimum space is occupied on the motor vehicle, thereby eliminating need for a layout change.
• the number of expansion chambers can be varied as per requirement.
• the exhaust system can be used in any type of vehicle including two-or three-wheeled motor vehicles or even in multi-wheeled vehicle with compact layout.
• crankcase 208 first bend

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Exhaust Silencers (AREA)
• Air-Conditioning For Vehicles (AREA)

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• 2021
  • 2021-04-15 EP EP21788413.9A patent/EP4136330A4/de active Pending
  • 2021-04-15 WO PCT/IN2021/050376 patent/WO2021210020A1/en not_active Ceased
  • 2021-04-15 CN CN202180026938.9A patent/CN115461530B/zh active Active

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