Oil residueparticleshavealargeimpactinprotectingthesealingsurfacesofheavydutyexhaustvalves.
Toincreasetheunderstandingofthemechanismbehindthis,thewearbehaviorofexhaustvalves
subjected toa flow ofhotairwithcontrolledamountsofoilparticlesofthreedifferentcompositionshas
been investigated.Air flow withoutadditionofoilwasusedasareference.
The degreeandmechanismsofsurfacedamageprovedtobesensitivetothetestparameters.
Residuesfromtheoilscontainingadditivesprovedtoformprotectivetribofilms, whiletheoilwithout
additivespromotedagglomerationofweardebrisonthesealingsurfaces.Thedryreferenceshowed
severewearwithdebrisscatteredoverthesurfaces.