Effect of combustion products of gasoline-ethanol blended fuel on corrosion of valve and cylinder head alloys of SI engines

In the present study, effects of different percentages of ethanol as a gasoline additive on high temperature oxidation behavior of cylinder head and valve alloys were investigated. A single-cylinder four-stroke engine was used to simulate the hot chamber of cylinder environment. Samples were located within the exhaust pipe and were deposited with ethanol blended gasoline combustion gases under certain operating cycles. Then in order to evaluate the oxide layer, the cross-section of samples were observed by scanning electron microscopy (SEM) and to determine the amount of oxygen, the surface of samples were analyzed by energy dispersive X-ray (EDX) technique. The obtained results exhibited that, thickness of oxide film was increased by increasing of the ethanol percentages and engine operating cycles. The most porous film was belonged to steel in 15% ethanol-containing fuel with 60 operating cycles. Metal loss in steel specimens was significantly more due to linear behavior of steel oxidation.