Search Results

During engine durability testing of a large diesel engine, several pistons were found to have experienced fatigue cracks along the combustion bowl edge directly over the pin bores. In order to determine the optimum design solution to this piston combustion bowl edge cracking problem, the performance of several power cylinder assemblies have been investigated to determine their effects on piston combustion bowl edge stresses. The power cylinder design variables examined in this analysis were piston skirt section thickness, piston compression height, pin inner and outer diameters and connecting rod end designs (Tee-Pee vs. straight). A finite element analysis of each power cylinder assembly was performed to ascertain the stresses existing on the piston combustion bowl edge. This finite element analysis found combustion bowl edge stresses from the thermal expansion effects only loading as well as those from the combined thermal expansion and combustion pressure loading.