A Review of Hybrid Vehicles Classification and Their Energy Management Strategies: An Exploration of the Advantages of Genetic Algorithms  
1 College of Mechanical Engineering, Guangxi University, Nanning 530004, China; [EMAIL_ADDRESS] (Y.Y. ); [EMAIL_ADDRESS] (K.Z. ); [EMAIL_ADDRESS] (Y.X. ); [EMAIL_ADDRESS] (M.P. ); [EMAIL_ADDRESS] (W.G. ); [EMAIL_ADDRESS] (L.L. ); [EMAIL_ADDRESS] (M.L.) transportation sector accounted for 55% of total global energy consumption. The automotive industry, as a core component of the transportation sector, plays a crucial role in the world's economic growth. However, as most vehicles rely on internal combustion engines (ICEs) for their operation, ICEs emit a variety of harmful gases such as CO\({}_{2}\), NO\({}_{2}\), NO, and CO during fuel combustion [1]. According to studies, the transportation sector contributes 25-30% of global greenhouse gas emissions, leading to environmental degradation, such as the greenhouse effect, and negative impacts on human health [2]. Figure 1 depicts recent energy usage within industries. Considering energy saving and environmental protection, society has put forward the demand for clean, efficient, and sustainable vehicles in urban traffic. Renewable energy-powered electric vehicles have a significant role to play in improving air quality and protecting the health of the population, as their emissions are only natural by-products rather than exhaust gases [3]. However, their limited range, inadequate charging infrastructure, and long charging time highlight their shortcomings [4]. In order to further improve driving performance and experience, effective solutions should be actively sought to complement the efforts to build a more efficient, convenient, and environmentally friendly transportation system. A hybrid electric vehicle (HEV) utilizes two or more power sources [6]. By merging the benefits of traditional ICEs with electric motors, HEVs effectively address the shortcomings of both ICE vehicles and electric vehicles (EVs) by integrating the engine and electric motor in their design [7]. Through a sophisticated energy management system, it coordinates the energy distribution between the engine and the battery/electrical unit to ensure that the engine operates in a highly efficient, low-energy-consumption operating range, while utilizing the regenerative braking function of the electric motor to maximize energy recovery. This significantly alleviates the technical challenges of limited battery energy storage and low range faced by pure EVs. In urban traffic, HEVs minimize frequent starts and stops through their unique operating mechanism, reducing idle time and demonstrating superior fuel economy and environmental performance compared to traditional internal combustion engine vehicles. In addition, HEVs are designed with a variety of structures that can be achieved by fine-tuning the conventional vehicle's structure, thereby reducing the complexity and difficulty of design. Compared to conventional vehicles, HEVs significantly reduce the weight and cost of key components such as the engine through rational structural configurations while ensuring no loss in driving performance and service life. Figure 1: European Union energy consumption percentage in different sectors [5]. This design not only retains the advantages of traditional vehicles, but also integrates the energy-saving characteristics of pure EVs, realizing the perfect integration of the advantages of the two models. HEVs present a new solution for the sustainable development of the automotive industry by significantly improving energy-saving and emission reduction performance. This is achieved through optimization, complementing, coordination, and cooperation between different energy sources. By integrating these diverse power sources effectively, HEVs not only ensure enhanced vehicle dynamics, but also maintain high standards of safety and comfort.