Cast Iron Graphite Effects on the Local Wear of a Flex-Fuel Engine Cylinder

This work consists in a study on the influence of gray cast iron graphite shape on the localized wear occurrence in engine block cylinders. The four cylinder automotive spark ignition internal combustion engine has been submitted to a complete dynamometer engine durability test. The tested engine is the one equipped with the flexible fuel technology, which is capable to work with both gasoline/ethanol fuels, in any mixture proportion. The specimen taken from the end-of-test engine block has been submitted to a 2D profilometer analysis, where region of localized wear at top dead center (TDC) zone was identified. The local wear region has been properly prepared epared and characterized through both scanning electronic microscopy (SEM) and metallography technics. Results have shown the appearance of the delamination-like structure with presence of cracks concentrated around the deformed graphite flakes, making possible to visualize how fragments could fracture from the surface, by the action of cyclic contact stresses.