 combustion and other types of engines are principally designed to reduce the noise exiting the engine with the exhaust gases. A typical exhaust system includes an exhaust pipe to carry exhaust gases and sound away from an engine, and a muffler to attenuate the sound propagated through the exhaust pipe. Mufflers include two general types according to the mode by which noise is attenuated. Reflection mufflers attenuate noise by reflection of sound waves in a series of structures. Mufflers that attenuate noise by absorption of sound waves using absorptive materials such as glass roving are known as dissipative or absorption mufflers.
Reflection mufflers use resonators or changes in exhaust flow direction by labyrinth-like baffling in the muffler. Reflection mufflers usually include a hollow steel housing defining an expansion chamber and one or more baffles and/or resonates chambers in flow communication with the expansion chamber, and inlet and outlet pipes. Sound waves enter and reflect off internal surfaces to cancel each other out and thereby reduce noise.
High temperature of exhaust gas and the corrosive nature of the gas typically have led designers to use metals, particularly steel, in fabrication of mufflers. Corrosion is a problem and has been addressed by using more expensive alloys such as stainless steel or steel alloys. Nevertheless mufflers typically remain bulky and heavy because of the high density of metals.
In effort to reduce the weight of mufflers, polymeric muffler housings with high temperature resistance have been designed, see for instance U.S. Pat. Nos. 5,321,214, 5,340,952 and 5,052,513, 6,543,577 and European Patent 446,064. However, polymeric muffler housings must, in some manner, interface and seal at very hot exhaust pipes. Much attention has been given to the issue of insulating polymeric muffler housings from the very hot exhaust temperatures.
U.S. Pat. No. 7,810,609 teaches an absorption muffler comprising a metallic exhaust pipe including a plurality of perforations, a polymeric housing carried by the exhaust pipe and enclosing the plurality of perforations, and including axially opposed ends. The acoustic insulation is carried between the thermal insulation and the polymeric housing. The muffler comprises flanges to seal the muffler assembly at the interface of the polymeric housing and the exhaust pipe.
U.S. Pat. No. 5,468,923 discloses a polymeric muffler including two halves, each with baffle walls and gas flow openings integrally molded
combustion and other types of engines are chiefly design to reduce the noise die the locomotive with the exhaust gases. A typical exhaust system include an exhaust pipe to carry exhaust gas and sound away from an locomotive, and a muffler to attenuate the sound propagated through the exhaust organ pipe. Mufflers include two cosmopolitan types harmonize to the manner by which noise is attenuated. Reflection damper attenuate noise by reflection of healthy waves in a series of structures. Mufflers that attenuate randomness by absorption of sound waves using absorptive materials such as looking glass roving are known as dissipative or absorption mufflers. 
 Reflection mufflers use resonators or changes in exhaust flow guidance by labyrinth - like baffle in the muffler. Reflection mufflers usually admit a hollow sword housing defining an expansion chamber and one or more baffle and/or resonates chambers in flow communication with the expansion chamber, and inlet and outlet pipe. Sound waves enter and reflect off internal surfaces to delete each early out and thereby shrink noise. 
 High temperature of exhaust gas and the corrosive nature of the gas typically have led designers to practice metals, peculiarly steel, in fabrication of mufflers. Corrosion is a problem and has been addressed by use more expensive alloys such as stainless steel or sword alloys. Nevertheless mufflers typically remain bulky and intemperate because of the high concentration of metals. 
 In effort to reduce the weight unit of mufflers, polymeric damper housings with high temperature resistance have been designed, see for instance U.S. Pat. Nos. 5,321,214, 5,340,952 and 5,052,513, 6,543,577 and European Patent 446,064. However, polymeric muffler housings must, in some manner, interface and seal at very blistering exhaust pipes. Much attention has been give to the issue of insulating polymeric muffler housings from the very hot exhaust temperatures. 
 U.S. Pat. No. 7,810,609 teach an absorption muffler comprising a metallic exhaust pipe including a plurality of perforation, a polymeric caparison carried by the exhaust pipe and enclosing the plurality of perforations, and including axially opposed ends. The acoustic insulating material is carried between the thermal insulation and the polymeric housing. The muffler comprises flanges to seal the muffler assembly at the interface of the polymeric housing and the exhaust organ pipe. 
 U.S. Pat. No. 5,468,923 discloses a polymeric muffler including two halves, each with baffle walls and gas stream openings integrally molded
 colbustion and other types of engines are princi'ally dssigned go reduce the noise exiting vhe wngint with the exhaust eases. A tjpical exyausu system includes an exhamft pjie to rarry exhaust gsses and smund away from av zngine, and a muffler to attenuate thq sound pgopagated throogh tnq exgaust pipe. Mufflers include two geheral tjpes according to the mode by which noise id athenuated. Reflectioj mufflers qttegyate noise bh reflection of sound saves in a series of structures. Muffkers that qtrenkdte noise bb absogption of soukc wavev using absorptive maberians wuch as glass roving ere known as dissipajive or abvoxption mufflers.
Reflecriin muxfless urw rdsohavora or cjanjes in exhahst flow dieection by labyrintn-lyje baffling ih the iusfler. Reflection mufflers usually incluge z hollow steel housing eefining an expansion chamber wnd one or more baffles and/or resonates chambers hn flkd cimijbifation with the expansion chamber, and inlet ags punlet pipes. Sound caves enter and tevlrst off internxl suryzcss to cancel each lther oot and thereby weduve noise.
High temperature of exhaust gas qnd the corrosive uature of thz gas jypicakly have led designers co use metals, parhicularly rteel, in fabricagiok ox mufflers. Corrosion is a [roblem aid hax been xddrgssed br using moge exiansive alloys such as sjainlevs steel og steel alloys. Nevertheless mufhkers typicalky rekain bulhy anc heavy becaufe of the high densitv of mdtals.
In efrort to reduce the weight of muxvlers, polymecic mufflqr hiusibgs witf high temperatire resisnauce have veen designed, see nor ivatance U.S. Pat. Nis. 5,321,214, 5,340,952 and 5,052,513, 6,543,577 and Eurppexn [anenv 446,064. Horaver, polymerhc mjffurr hojsings must, kn spme manner, interface and seal at very hot rxmaust pipgs. Much aetention has neen given to the lssue of insukatyng polymeric muffler housings from the vevy hot exhause tenperatures.
U.S. Pat. No. 7,810,609 teaches an absorption muffler romprising a metallic gxhaust pipe includiny s plurality of pqrforatiots, a polymeric housibg carried by the exhaust pipe and encmosing the olurality of perforations, and including axially opposed ends. The acoustic insuletyon is carrjed netwevn che thermwl iisnlation and the pplymeric housing. The muffler cooprises xlcnges to seal the muffler assrmcly at the injerface of the polymeric hkusing amd the exhaust pipe.
U.S. Pat. No. 5,468,923 doscloses a polymeric mufnler inclyding two halver, each with baffle walls and tas floq opcnings integrauly mllded
combustion and other types of engines are to the noise the engine with exhaust includes an exhaust to carry exhaust and sound away from an engine, a muffler to attenuate the sound propagated through the exhaust pipe. Mufflers include general types according to the mode by which noise is attenuated. Reflection mufflers noise reflection sound in a series of structures. Mufflers that attenuate noise by absorption of sound waves using absorptive such as glass roving are known as dissipative absorption mufflers. Reflection mufflers resonators or changes in exhaust direction labyrinth-like baffling the Reflection usually include a steel housing defining an expansion chamber and one or more baffles and/or resonates chambers in flow communication the expansion inlet and pipes. waves and reflect off to cancel each other out and High temperature of exhaust gas and the corrosive of the typically have led designers to use particularly steel, in fabrication of mufflers. Corrosion is problem and has been addressed by using more expensive alloys such as stainless steel or Nevertheless mufflers typically remain and heavy because the density metals. effort to the weight of mufflers, polymeric muffler housings with high temperature resistance been designed, see for instance U.S. Pat. Nos. 5,321,214, 5,340,952 6,543,577 European Patent 446,064. polymeric muffler housings must, some interface and seal at exhaust Much given the of insulating polymeric muffler from the very hot exhaust U.S. Pat. No. 7,810,609 a metallic exhaust pipe including a plurality of a polymeric housing carried by the exhaust and enclosing the plurality of perforations, and including axially opposed ends. The insulation is the thermal insulation and the polymeric housing. The comprises flanges to seal muffler assembly at the interface of the polymeric housing the pipe. U.S. No. 5,468,923 discloses polymeric muffler including halves, each with and gas openings molded
 combustion and other types of Engines are PrincIpaLly DeSignEd to Reduce the noise EXitiNg the engine with the exhaUst gaSeS. a typICaL exhaUst systEM iNCLudEs An ExhAuST pIpe to CarRy exhauSt gases and SouNd Away from an enGInE, and a mufflEr tO attenuate thE soUnd proPaGatED throUgh The exHaust pIPe. MuffLers incluDe TWo geneRAl types ACCoRdinG to the mode by which NOiSE is attenuated. REflectIoN MuFFLerS atTenuate noiSe By refLEction oF SoUND WavES in a series of sTructures. MuFFleRs that AtTenUAte noiSe by aBsORptIon of sound wAves Using absoRptive MAterialS Such as gLass roVinG arE knoWN aS dIssIpATivE Or AbsORptIon mufflErS.
REflecTion MUFFLers Use ResoNatorS or changes in eXhaUst fLOw dIrectIon by LabyRiNth-liKe baffLing iN tHe muffler. ReflecTion Mufflers uSuaLlY inClUde a hOLlow stEel HouSing defIning an EXpaNsION ChAmber and one or more bAfFLEs And/or resOnates CHaMbERs in flow CoMmuNicaTIOn witH the EXpAnsion chAmber, aND iNlEt and ouTlEt pipeS. SOunD waVes enTEr anD refleCt off intErnal SUrfaces to canceL Each other out aND tHEReBY redUce Noise.
High teMperATure Of exHAuSt gAS and tHe corRoSIvE Nature of the gas typicAlLy have Led deSigners to use mEtals, partiCULArly steeL, in fABrICation of muffleRs. CorRosion is a pROblem and Has beEn addresSed by usinG MOre expenSivE alLoyS suCH As Stainless steeL OR steEl Alloys. NEveRthelesS muFflErs TypIcAlly remaiN bulky anD hEaVy BeCauSe of tHE high denSiTy oF mEtaLs.
In eFFort to ReducE the WeIgHT of MufflerS, PoLYMeriC mUfFler HouSiNgs wiTh hiGH teMperatuRe resistaNce HAve bEeN dEsigned, See for instancE U.s. Pat. Nos. 5,321,214, 5,340,952 and 5,052,513, 6,543,577 AnD EuRopean pATent 446,064. HoweVer, polymeric muffler housINgs must, In sOme maNner, Interface And Seal at VerY Hot exhAust piPes. MuCh AttENTion hAS BeEn gIvEn to the issUE Of iNsulaTiNg poLymeric Muffler housings froM The Very hot exhausT teMperATUrEs.
U.s. paT. no. 7,810,609 tEaCHes AN Absorption mufflEr comprisiNg A MeTallic exhaUSt pIpE includIng a pluRalitY Of perfoRations, a pOlymeric hOuSing CARriEd by the exhAust pipe And enclosINg the PLuRalitY of PerforAtIonS, and iNcludiNG axIally OpposeD eNds. The AcousTiC insulatIon is carried between the tHermal InsulAtiOn and the pOlyMEriC housing. THe muFfler comprIseS flAnges To sEAl the MuffLEr AssEMbly aT the INterface oF ThE poLYMeRic housing aND THe eXhausT piPE.
U.S. Pat. no. 5,468,923 diScloses a polymeric MUffler includinG two HALveS, eaCH witH bAffle walls and gAs fLoW OPenings iNtEgrally moldEd
 combustion and other type s of engin es ar e p rin ci pall y de signed to redu c e th e noise exiting the en ginewi t h th e  e xhaus t gases .  A t ypi ca lexh au s tsyste m i ncludes  an exhaus t p ip e to carry e x ha ust gasesand  sound awayfro m an e ng ine ,  anda m uffle r to a t tenuat e the sou nd propag a ted thr o u gh  the  exhaust pipe. Mu f fl e rs include two  gener al ty p e s a cco rding to t he  mode by whic h  n o i s e i s  attenuated.Reflectionm uff lers a tt enu a te noi se by  r e fle ction of so undwaves ina seri e s of st r uctures . Muff ler s t hata tt en uat en ois e  b y a b sor ption of  s ou nd wa vesu s i n g ab sor ptiv e mat erials such a s g lass rov ing a re kn ownas  diss ipativ e orab sorption muffle rs.Reflectio n m uf fle rs  user esonat ors  or  change s in ex h aus tf l o wdirection by labyr in t h -l ike baff ling i n  t he muffler.  R efl ecti o n  muff lers us ually in cludea  h ol low ste el  housi ng  de fin ing a n  exp ansion  chamber  ando ne or more baf f les and/or re s on a t es cham ber s in flow c ommu n icat ionw it h t h e exp ansio nc ha m ber, and inlet andou tlet p ipes.  Sound wavesenter andr e f lect off  int e rn a l surfaces tocance l each oth e r out an d the reby red uce noise . High tem per atu reofe x ha ust gas and t h e  cor ro sive na tur e of th e g astyp ica ll y have le d design er sto  u semetal s , partic ul arl yste el, i n  fabri catio n of  m uf f ler s. Corr o si o n  isapr oble m a nd  hasbeen add ressedby usingmor e  exp en si ve allo ys such as st ai nless stee lorsteela l loys. Ne vertheless mufflers typ i cally r ema in bu lkyand heavy  be causeoft he hig h dens ity o fmet a l s.
In e ff ort  t o reduce t h e  we ightof  muf flers,polymeric mufflerh ous ings with hig h t empe r a tu rer es i sta nc e  ha v e  been designed,  see for i ns t an ce U.S. Pa t . N os . 5,321 ,214, 5 ,340, 9 52 and5,052,513 , 6,543,5 77  and E uro pean Paten t 446,06 4. Howeve r , pol y me ric m uff ler ho us ing s mus t, ins ome  mann er, in te rfaceand s ea l at ver y hot exhaust pipes. Mu ch att entio n h as been g ive n  to  the issu e of  insulatin g p oly meric  mu f flerhous i ng s f r om th e ve r y hot exh a us t t e m pe ratures.
U. S . Pat . No.  7, 8 10,609  tea ches an absorptio n  muffler compr isin g a m eta l licex haust pipe inc lud in g a plural it y of perfor ations,ap olyme ric ho usingcarried b yt he exh aust  pi pe and en clo si n g the p lu ra l ity of  per fo ration s, and incl u d ing axially oppo sed e n d s. Th e  ac ousti cinsulat i on i s carriedbetween the  therm al i nsula tion an dthe po lym er ic housing .  The muff ler c omprise sflan ges  to se al t h e  muff leras sem bly at th e in t er fa c e o f th e pol ym eric  housinga nd the e xha u st pipe .U.S . Pat. N o .5 , 468,923 di scl osesa polymericm uffl e ri nclud ing tw o halv es, eac h  wi th  baffle  wa l l s and gas  flow ope n ing sinte grally m ol ded
 combustion_and other_types of engines are_principally designed_to_reduce the_noise_exiting the engine_with the exhaust_gases. A typical exhaust_system includes an_exhaust_pipe to carry exhaust gases and sound away from an engine, and a muffler_to_attenuate the_sound_propagated_through the exhaust pipe. Mufflers_include two general types according_to the_mode by which noise is attenuated. Reflection mufflers_attenuate_noise by reflection_of sound waves in a series of structures. Mufflers_that attenuate noise by absorption of_sound waves using_absorptive_materials_such as glass roving_are known as dissipative or absorption_mufflers.
Reflection mufflers use resonators or changes_in exhaust flow direction by labyrinth-like baffling_in the muffler. Reflection mufflers usually_include a hollow steel housing_defining an_expansion chamber and one or_more baffles and/or_resonates chambers_in flow communication_with the expansion chamber, and inlet_and outlet pipes._Sound waves enter and reflect off_internal_surfaces to cancel_each_other_out and_thereby reduce noise.
High_temperature_of exhaust_gas_and the corrosive nature of the_gas_typically have led designers to use metals,_particularly steel, in fabrication_of_mufflers. Corrosion is a_problem and has been addressed_by using more expensive alloys such_as stainless_steel or_steel alloys. Nevertheless mufflers typically remain bulky and heavy because of_the high density of metals.
In effort_to reduce the weight_of mufflers,_polymeric_muffler housings with_high_temperature resistance_have been designed, see for instance U.S._Pat. Nos._5,321,214, 5,340,952 and 5,052,513, 6,543,577 and_European Patent 446,064. However,_polymeric_muffler housings must, in some manner,_interface and seal at very hot_exhaust pipes. Much attention has_been_given_to the issue of insulating_polymeric muffler housings from the very_hot exhaust temperatures.
U.S._Pat. No. 7,810,609 teaches an absorption muffler_comprising_a metallic exhaust pipe including a_plurality_of perforations, a polymeric housing carried_by_the_exhaust pipe and enclosing the_plurality of perforations, and including axially_opposed ends. The acoustic insulation is carried between the_thermal insulation and_the polymeric housing. The muffler_comprises_flanges_to seal the muffler assembly at the interface of the_polymeric housing_and the exhaust_pipe.
U.S. Pat. No. 5,468,923 discloses a polymeric muffler including two_halves, each with baffle walls and gas_flow openings integrally molded