Design and Optimization of an SUV Engine Compartment Bottom Shield Based on Kriging Interpolation and Multi-Island Genetic Algorithm

Engine compartment thermal management can achieve energy saving and emission reduction. The structural design of the components in the engine compartment affects the thermal fluid flow performance, which in turn affects the thermal management performance. In this paper, based on the phenomenon that the surface of the parts in the engine compartment is abnormally high due to design defects of an SUV engine compartment bottom shield, the engine compartment is modeled and analyzed by CFD using the software STAR-CCM+. It is not conducive to the heat dissipation, so the bottom shield needs to be redesigned. To redesign the shape of the bottom shield, four dimensions and one coordinate value were selected as the design parameters, and the oil pan maximum surface temperature was selected as the optimization target. The Latin hypercube sampling method was used to sample the space uniformly, and the experimental design plan was constructed and simulated. The Kriging interpolation model was used to fit the oil pan maximum surface temperature; the multi-island genetic algorithm is used to optimize the simulation results to obtain the optimal design plan. It has been verified that under the same working conditions, the optimal design plan can reduce the oil pan maximum surface temperature by about 7°C, and the bottom shield surface temperature near the high-temperature exhaust pipe can be reduced by about 10°C, and the heat flow in the compartment can flow out smoothly, which eliminates the phenomenon of heat recirculation in the compartment caused by the design defect of the bottom shield.