Resumo:
The intensificationofclimatechangeandthedeteriorationofairqualitydemand
sustainable energysolutionsthatreconcilevehicularmobilitywiththemitigationofgreen-
house gas(GHG)emissions.Amongthealternatives,biomethaneemergesasaviable
substitute forcompressednaturalgas(CNG),duetothesimilarityoftheirphysicochemical
propertiesanditspotentialtoreduceGHGemissionswithoutrequiringstructuralchanges
to therefuelinginfrastructure.Inthiswork,throughnumericalsimulationsusingthe
GT-SUITE® software,thecalibrationofaspark-ignitionenginecommerciallyemployedin
light-dutyvehiclesoriginallydesignedforCNGwasdeveloped.Thestudyconsideredboth
the directfuelsubstitutionandtheoptimizedignitiontimingcalibrationtomaximize
performanceandminimizeGHGemissions.Suchmodificationsaredeemedfeasiblesince
they donotrequirephysicalchangestotheengine,butratheranadjustmentoftheengine
map intheelectroniccontrolunit.Inthedirectsubstitutioncase,withoutcalibration
adjustments,nosignificantlossesintorqueandpowerwereobserved,withrecorded
reductions ofupto1.94%in CO2, 4.03%in CO, and2.26%in NOx. Withignition
timing calibration,retardedby1° to 3° compared toCNG,performanceimprovements
wereachieved,withgainsinpowerandthermalefficiency,inadditiontofurtheremission
reductions, reaching2.30%for CO2, 4.48%for CO, and1.64%for NOx. Whenassessing
the substitutionofCNGbybiomethane,basedontheGHGemissiondataobtainedfrom
numericalsimulations,theBrazilianvehiclefleet,andtheestimatedfuelconsumption
and mileageofCNG-poweredvehiclesinBrazil,itwasobservedthatthereplacement
of CNGbybiomethaneinthenationalfleetcouldmitigateupto79.51thousandtons
of CO2 and 18.12thousandtonsof NOx peryear.Theenergydemandassociatedwith
the purificationprocesswasalsoevaluated,highlightingthattechnicalfeasibilitymustbe
accompanied bypublicpoliciesandspecificlegislationtofosterbiomethaneproduction
and vehicularuse.Theresultsdemonstratethatbiomethane,particularlywithproper
calibration, isacompetitiveandenvironmentallyadvantageousalternativecompared
to CNG,contributingtothedecarbonizationofthetransportationsectorandtothe
valorizationoforganicwasteinBrazil.Theimplementationofthistechnology,coupled
with regulatoryincentivemechanisms,mayincreasetheshareofrenewablefuelsinthe
energy matrixandsignificantlyreduceairpollution.
