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.

优化气门正时和燃油系统的参数可以促进具有高效率和低排放的大功率柴油机的应用。尽管如此，仍需要考虑活塞的热负荷问题。建立了大功率柴油机工作过程的计算模型和活塞热负荷的有限元模型。确定了活塞的热边界条件，并将其应用于活塞的热负荷计算，并使用温度插塞法测量了活塞的关键温度点，以验证模型的正确性。随后，基于气门正时和燃油系统，利用影响因素对活塞的热负荷评估参数的模式进行了分析。使用灰色关联法分析了评估参数和影响因素之间的敏感性和权重。提出并应用了一种综合影响因素的活塞热负荷综合评价指标的方法。研究结果表明，活塞热负荷模型的误差范围很小，敏感性分析表明影响因素与活塞热负荷评估参数之间具有相关性，综合评价方法可以定量分析活塞的热负荷。