Power-split hybrid technologies have been transformed from single mode to multimode to realize even greater savings in fuel and more powerful output. However, the optimization procedure of the mode shift map for multimode hybrid electric vehicles (HEVs) has not been formalized. In this paper, the types of mode shift are first classified as direct/indirect and conditional/unconditional. The optimal shift path with minimum energy variation for the indirect mode shift is formulated as a shortest path problem and solved by Dijkstra’s algorithm. By taking the energy loss during mode shift into consideration, the method for designing a mode shift map is presented from the perspective of the normalized system efficiency. The derived mode shift map is combined with a novel energy management strategy, referred to as normalized efficiency maximum strategy, to formulate an integrated real-time control strategy for the multimode HEV. Finally, by comparing two other commonly used strategies, dynamic programing and equivalent consumption minimization strategy, the proposed control strategy shows great potential in improving fuel economy while maintaining smooth engine operation, thus leading to better ride comfort of the vehicle.

中文翻译：

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多模混合动力总成的换挡计划与控制策略设计

动力分配混合动力技术已从单模转换为多模，以实现更大的燃油节省和更强大的输出。然而，用于多模式混合动力电动汽车（HEV）的模式转换图的优化程序尚未正式化。在本文中，模式转换的类型首先分类为直接/间接和有条件/无条件。间接模式换挡具有最小能量变化的最优换挡路径被公式化为最短路径问题，并由Dijkstra算法求解。通过考虑模式转换时的能量损失，从归一化系统效率的角度提出了一种设计模式转换图的方法。导出的模式转换图与一种新颖的能源管理策略（称为标准化效率最大化策略）结合在一起，为多模式混合动力汽车制定一个集成的实时控制策略。最后，通过比较其他两种常用策略，即动态编程和等效消耗最小化策略，所提出的控制策略在改善燃油经济性的同时，还保持了发动机的平稳运转，显示出巨大的潜力，从而带来了更好的车辆乘坐舒适性。