MG MG6 Series 2011 - Operation-1.8 T Inlet and Exhuast System

EngineManifold&ExhaustSystem
Engine
Operation-1.8TInletandExhuastSystem
AirCleaner–1.8T
Airenterstheairductatthefrontoftheenginebayabove
theradiator.Itpassesthroughtheaircleanerelementwhere
abrasivematerialisremovedfromtheairandisretainedbythe
cleaner.
Filteredairfromtheaircleanerelementpassesthroughthe
ducttotheturbocharger.Theturbochargercompresses
theairwhichexitsintotheintercoolerductingandintothe
intercooler .Itisanair-to-airintercoolerwithrowsofcooling
nstocoolthehighchargeairtemperaturegeneratedby
theturbocharger .Hotairislessdensethancoolerairand
containslessoxygenatthesamepressure.Theintercooler
increasesthedensityofthechargethusincreasingtheoxygen
contentimprovingvehicleperformance.Thecooledexitsthe
intercooler ,passesthroughtheductingandTMAP1sensorto
theETB.
InletManifold-1.8T
AirfromtheaircleanerassemblyowsthroughtheETBinto
theinletmanifold.Theairseparatesintothefourinlettracts.
Thefuelinjectors,locatedattheendofeachtract,injectfuel
intotheinletmanifoldtractswhichatomisesintheair.The
air/fuelmixisdeliveredtothecylinders.
ExhaustManifoldandExhaustSystem–1.8T
Hotexhaustgasespassfromeachexhaustportintothe
exhaustmanifold.Themanifoldbranchesconvergeintoa
singleangewhichenterstheturbocharger.Theturbocharger
increasesinletmanifoldpressureforcingmoreairintothe
cylindersandthiscombinedwithincreasedfuelling,resultsin
greaterenginetorqueandpower.Theexhaustgasesexitthe
turbochargerandpassthroughthecatalyticconverterand
intotheexhaustsystemwheretheyenterthesilencers.The
primarysilencerisanabsorptiontypewithperforatedtubing
passingthroughthesilencerbody.Theperforationsallowthe
noiseenergytopenetratethesilencingmaterialreducingthe
exhaustnoisetoanacceptablelevelwhilstalsominimising
therestrictiontotheow.Thesecondaryrearsilencerisa
reectivetypesilencerthatusesinternalbafestoreectthe
soundwavestowardsthesourcetoreducenoiselevels.
Three-wayCatalyticConverterTWC-1.8T
Warning:TWCsoperateatveryhightemperatures;
therefore,extremecautionisnecessarywhenhandling
thiscomponent.
Caution:Foracatalyticconvertertoworkefcientlyand
topreventprematurefailuredonotrunonleadedfuel
anddonotallowunburntfueltopassthroughtheexhaust
system.
Primarycombustionoccursinthecombustionchamber.The
exhaustgasespassthroughtheexhaustmanifoldwherethey
entertheTWC.TheTWCisonlyeffectiveafterreaching
itsminimumoperatingtemperature.Theexhaustgasespass
throughthemonolithstructurewhichiscoatedinplatinumand
rhodium(thecatalysts)wheretwoprocessesoccur,reduction
andoxidation.NitrogenOxideNO
X
isreducedtoNitrogen(N)
whichgivesupitsoxygenmoleculestotheCarbonmonoxide
(CO)toformCarbondioxide(CO2).Hydrocarbons(HC)
andCOwillcontinuetoburninthecatalyticconvertorwith
anyoxygenthatremainsintheexhaustgases.Thisresultsin
oxidationofhydrogenandcarbontoproducewaterH
2
Sand
CO2.
2
.
Version2.0249