Life Cycle Analysis of an Internal Combustion Engine Through Thermal History of the Cylinder Head and Scanning Electron Microscopy

Internal combustion engines are subjected to severe service conditions, such as high pressure and temperature, and deficient lubrication. These service conditions are similar for all internal combustion engines, including two or four strokes engines. This work is part of a research program that has the objective of identifying the main wear mechanisms of some important components of a two stroke engine. In this initial stage, an aero-model IC Engine 1,2Hp (combustion chamber of 7.64 cm3, course of 18.4 mm) was tested, working at 11,600rpm, with no external applied load and using a conventional fuel with 10% nitro-methane (18% of lubricant, which contains of 20% castor oil and 80% synthetic oil). The wear was monitored through the evaluation of the thermal history of the cylinder head and SEM was used for the characterization of the: (1) piston (AISI52100 steel), (2) pin (Al-Si) and (3) cylinder head. All data related to the materials and to the chemical composition of the oxides formed were obtained through EDS. The development of the oxide layer, pittings, micro-cracks and other wear mechanisms are discussed and related to the materials properties and environmental conditions of testing.