ASSESSMENT OF EXHAUST VALVE DEBRIS FROM GREEN FUEL COMBUSTION

Abstract

Used cooking oil (UCO) has shown promise as a short-term alternative fuel for compression ignition engines. To evaluate its long-term effects, this study conducted an endurance test using diesel-UCO blends. Results showed minimal wear on the engine head’s working surface. Among the tested blends, DF60UCO20Pn20—with the lowest cetane number and highest oxygen content—exhibited the shortest combustion time and longest ignition delay. Engine head and exhaust valve deposits were analyzed and compared to those from emulsion fuels. Visual inspection revealed deposits across all fuels, while SEM and EDS analysis showed that DF95UCO5 produced more carbon buildup than both DF60UCO20Pn20 and pure diesel.