Research on thermal deformation of cylinder bore with orthogonal experiment method of aluminum alloy cylinder block in diesel engine

Abstract

Using aluminum alloy materials provides an efficient and direct method for achieving engine weight reduction. In this study, a thermo-mechanical coupling simulation model of the diesel engine was established to investigate the deformation of cylinder bores in both cast iron and aluminum alloy cylinder blocks. The reliability of the simulation model is validated by the temperature field test of the cast iron cylinder. Four evaluation indexes, namely average roundness, cylindricity, coaxiality, and light leakage, were used to assess the deformation of the cylinder bore. The results indicate that the temperature is the primary factor contributing to the deformation in both cast iron and aluminum alloy cylinder bores. Under thermo-assembly condition, the average roundness, cylindricity, coaxiality, and light leakage rate of aluminum alloy cylinder bore were observed to be higher by 36.71 %, 12.69 %, 14.77 %, and 18.85 %, respectively, compared to those of cast iron cylinder bore. To decrease the deformation of the cylinder bore, the orthogonal experiment method was used to study the three factors affecting the heat dissipation of the water jacket. It was discovered that extending the water jacket extends upward was the most effective way to reduce the temperature of the cylinder block. By selecting the optimal combination scheme for simulation calculations, an optimized cylinder temperature of 162 °C, with the maximum deformation of the cylinder bore decreasing by 13.64 %. Additionally, the average roundness, cylindricity, coaxiality, and light leakage rate of the cylinder bore showed reductions of 17.48 %, 21.8 %, 23.00 %, and 14.10 %, respectively, when compared to the original aluminum alloy cylinder block.