Numerical study of flow field optimization and solid temperature distribution characteristics for a two-cylinder motorcycle engine based on the coupling analysis method of CFD and FEM

Evaluating engine cooling performance and predicting component temperatures are crucial for motorcycle engine thermal management. This study employed CFD to optimize coolant flow uniformity in a two-cylinder engine’s water jacket, and used CFD-FEM coupling to obtain the temperature distribution of solid components. Component temperatures were measured via the hardness plug method, and the simulation accuracy was validated against experimental data. After optimizing the water hole layout, the coolant velocity uniformity and heat transfer coefficient in the water jacket were improved. Temperature results indicated that the maximum temperature of the cylinder head, approximately 240°C, occurred in the exhaust bridge area of the combustion chamber. The cylinder block reaches a maximum temperature of about 150°C, with the higher temperature zone located in its mid-to-upper section. A comparative analysis reveals that the modified structure achieves a significant reduction in the maximum temperature compared to the original design and the maximum temperature reductions of engine head reaches 20°C. These temperature results provide quantitative benchmarks for evaluating motorcycle cooling system designs.