正交网格优化法是求解柴油机性能优化问题的一种比较有效的方法．对这种优化方法进行了较详细的理论分析，给出了优化变量域的一种收缩方法和计算收敛准则．采用这种方法，结合某中速大功率柴油机，进行了不同优化变量水平数的多方案单目标优化实例计算，得到了一些规律性认识；指出了在综合考虑优化计算精度与计算时间的前提下，优化变量水平数选取９、１１时是比较合适的 The orthogonal grid optimization method is a more effective method to solve the diesel engine performance optimization problem. A more detailed theoretical analysis of this optimization method is given, and a shrinkage method and calculation convergence criterion are given. In this method, combined with a medium-speed and high-power diesel engine, multi-program single-objective optimization examples with different levels of optimization variables are calculated and some regularities are obtained. It is pointed out that under the premise of comprehensively considering the optimization calculation accuracy and calculation time , The optimal level of variables selected 9,11 is more appropriate