Navistar MaxxForce 9 - Graph 7: Inverted Exhaust Gas Temperatures (Inefficient Doc)

DIAGNOSTICMANUAL
10.7.GRAPH7:INVERTEDEXHAUSTGASTEMPERATURES(INEFFICIENTDOC)
1.DieselOxidationCatalystInlet
Temperature(DOCIT)(degrees
Fahrenheit)[Red]
2.DieselParticulateFilter(DPF)soot
load(percent)[Blue]
3.DieselOxidationCatalyst(DOC)
atoperatingtemperatureand
stabilized.
4.DieselParticulateFilterOutlet
Temperature(DPFOT)(degrees
Fahrenheit)[Green]
5.DieselOxidationCatalystOutlet
Temperature(DOCOT)(degrees
Fahrenheit)[Purple]
Figure32Graph7:InvertedexhaustGasTemperatures(InefcientDOC)
GraphAnalysis:
ThisgraphshowsinvertedexhaustgastemperaturesindicatinganinefcientDieselOxidationCatalyst(DOC).
InvertedtemperaturesintheexhauststreamoccurwhentheDieselParticulateFilterOutletT emperature
(DPFOT)ishigherthanDieselOxidationCatalystOutletT emperature(DOCOT)aftertheDOChasreached
operatingtemperatureandstabilized(seecallout3,graph7).Thisiscausedbyunburnedfuelreactingwith
theDPF,insteadoftheDOC,causinganincreaseinDPFOT.Thistestdoesnotgivepassorfailresults.Itonly
allowstheusertovalidateoperationoftheaftertreatmentsystembymonitoringexhaustgastemperatures.
131
https://www.truck-manuals.net/