Volvo VN - Exhaust Aftertreatment System Components and Operation; Selective Catalytic Reduction (SCR)

Volvo,US10EmissionsSolution347
ExhaustAftertreatmentSystemComponents
andOperation
SelectiveCatalyticReduction(SCR)
SelectiveCatalyticReduction(SCR)isanemissions-reductiontechnologywiththe
abilitytodelivernear-zeroemissionsofnitrogenoxides(NOx),asmog-causing
pollutantandgreenhousegas.SCR’sperformancehasbeenprovedinmillionsof
milesofreal-worldtruckoperationsinothercountries,aswellasinlong-termeld
testsintheU.S.
SCRreducesNOxemissionstoverylowlevels,whileatthesametimedelivering
excellentfueleconomyandreliability.Thesystemdoesn’tchangethedesignor
operationofthebasicengine.Rather,SCRisanAftertreatmentsystemwhich
convertsNOxintheexhauststreamintoharmlessgases.Moderndieselsalreadyuse
exhaustAftertreatmentsystems,calleddieselparticulatelters,tocontrolemissions
ofanotherpollutant,soot(alsoknownasparticulatematterorPM).
SCRworksbyinjectingDieselExhaustFluid(DEF)intotheexhaust.DEFisa
solutionofultra-purewaterandurea.DEFworkswiththeheatoftheexhaustand
acatalysttoconvertNOxintonitrogenandwatervapor-twoharmlessandnatural
componentsoftheairwebreathe.Theendresultiscleanerair,excellentfuel
efciencyandareliableemissionscontrolsystemfortoday’smoderndieselengine.