The failures analysis of internal combustion engine pistons

In today?s world, because of the fact internal combustion engines have been made with high velocity, high compression rates, short stroke wide cylinder diameter, internal combustion engines must be made of light metals which can do excellent heat transfer. For this reason, engines are made of aluminium alloy. As a result of the reducing of emission levels and the raising of engine performance, engine parts work in harder conditions.This work has been done with the aim of determining the reasons that cause disorders in pistons used in internal combustion engines. The work was done on two ignition engine pistons having disorders depending on the use of 10-grade mineral oil from among 15 pistons with disorders belonging to compression ignition engines and spark ignition engines. In order to determine whether the cause of the disorders of the pistons having disorders depending on the use of 10 grade mineral oil stems from material defects, spectro-analysis was done on these pistons. The parts with disorders, of these pistons having been cut, metallographic investigation was done. In the material analyses which were done no structural defect was seen in the material. It was seen that the disorders in both of the pistons stemmed from non-standard fuel use.Due to the fact that the viscosity of the 10 grade mineral oil is higher than the viscosity of the diesel oil, the injection characteristic is bad. When 10 grade mineral oil burns it causes congestion in the injector, forming carbon, soot accumulation. Congested injector causes dribbling in the fuel. At the end of dripping, with the burning of the fuel accumulating on one point detonation arises. Detonation causes disorders in the engine parts.Key words: Piston, piston failures.