Evaluation and sensitivity analysis of a piston’s thermal load in a high-power diesel engine

Abstract

Optimising the parameters of valve timing and fuel system can promote the applications of high-power diesel engines that have high efficiency and low emissions. Nevertheless, the problem of the piston’s thermal load needs to be considered. In this paper, a calculation model for the working process of a high-power diesel engine and a finite element model of the piston’s thermal load were established. The piston’s thermal boundary conditions were determined and applied to the calculation of the piston’s thermal load, and the key temperature points of the piston were measured using the temperature plug method to verify the correctness of the model. Subsequently, analysis of the patterns of the piston’s thermal load’s evaluation parameters was carried out with the influencing factors based on the valve timing and the fuel system. The sensitivity and the weighting between the evaluation parameters and influencing factors were analysed using the Grey Correlation method. A new method for the comprehensive evaluation index of the piston’s thermal load with the influencing factors was proposed and applied. The research results show that the margin of error of the piston’s thermal load’s model was small, and sensitivity analysis revealed correlation between the influencing factors and the evaluation parameters of the piston’s thermal load, the comprehensive evaluation method could quantitatively analyse the piston’s thermal load.