This book presents a comprehensive overview of power-split device (PSD) design. It discusses vehicle energy consumption characteristics, hybrid vehicle power request solutions, typical configurations, operating principle and simulation technology of PSD hybrid system, a multi-factor integrated parametric design method and a dynamic coordinated control method for PSD hybrid system. It also describes the finite element analysis, thermal analysis and optimization of the PSD based on a surrogate model, explains the theory behind the design and the simulation, and provides concrete examples. It is a valuable resource for researchers and the engineers to gain a better understanding of the PSD design process.