Hybrid power system refers to more than two power sources with different working principles, which are matched together to make the system run. The purpose of hybrid power system is to make full use of the advantages of all prime movers and realize the performance that can not be achieved by a single prime mover. In 1900, the first hybrid vehicle came out, but it was not used by many people because of many reasons, such as cost, mileage and so on. In the 1970s, in order to solve the oil crisis and other problems, people’s attitude towards hybrid electric vehicles quietly changed. Countries all over the world are discussing the practicability of various hybrid electric vehicles. With the development of oil engine technology, the crisis is gradually alleviated.
In recent years, with the gradual improvement of people’s awareness of environmental protection, the development of new energy vehicles began to receive people’s attention and social support. Hybrid electric vehicles can reduce fuel consumption, increase fuel diversification, reduce CO2 emissions and clean emissions. The work of popularizing the use of hybrid electric vehicles is gradually carried out. It has become an irresistible force, changing the structure and composition of vehicles and developing towards practicality. According to automobile manufacturing and production, hybrid electric vehicles will account for 25% of the world automobile market in 2020.
Toyota Corporation of Japan put the hybrid electric vehicle Prius into small batch production in 1997. It uses a 1.5-liter 4-cylinder engine, a 33kw permanent magnet synchronous motor to drive the vehicle and feed back braking energy. The generator is used to charge the battery. The fuel consumption of 100 kilometers under urban working conditions is only 4.5L, and that of 100 kilometers under high-speed working conditions is only 5.2L. After so many years of improvement of the first generation, second generation and third generation schemes, it has entered the stage of mass production, Prius is the first batch of mass-produced and most mature hybrid cars in the market. Prius’s hybrid power transmission system is the most advanced technology at present. The combination of engine and motor makes an epoch-making change in vehicle performance. It not only has lower fuel consumption than previous vehicles, but also realizes a high level of low exhaust emission in the world. Japan’s Nissan Tino was launched in 2000. It uses a 1.78l 4-cylinder engine, a 17kw permanent magnet synchronous motor to drive the vehicle and feed back braking energy. Another motor starts the engine and charges the battery, but it has been discontinued due to cost and technical problems. The general perception vehicle in the United States also adopts the hybrid type. It began production in 1998. It uses a 1.3-liter 3-cylinder engine. The 3-cylinder motor drives the rear axle and feeds back the braking energy. The 10kW motor drives the front axle, starts the engine, charges the battery and feeds back the braking energy. It uses shift elements to realize multiple fixed transmission ratios and improve the transmission efficiency during high-speed operation. At present, it has been mass produced. In addition, the development of GM, Ford and Daimler Chrysler hybrid prototype vehicles in 2000 can meet the fuel consumption of 3 liters or close to 3 liters of gasoline when driving 100 kilometers. In 2015, the golf GTE plug-in hybrid vehicle launched by Volkswagen has been officially introduced into the Chinese market.
At present, one of the development trends of new energy vehicle technology is hybrid vehicle technology. In this trend of industrialization, domestic enterprises have also begun to connect with the world. From the introduction of Prius hybrid car by FAW Toyota, an early joint venture, to the current competition among FAW, SAIC, Dongfeng, Chang’an, Chery, BYD and other enterprises, such as Roewe 550 hybrid car developed by SAIC passenger car with its own brand, and Roewe 750 hybrid car was listed in 2010; In 2007, Chang’an Automobile Company successfully developed Jiexun hybrid vehicle, which was put into operation in Beijing and Chongqing in 2009 and officially put into the market in 2011. It is the first independent brand hybrid car listed in China. In 2014, the sales volume of Chang’an new energy vehicles reached 150000, and it is expected that the sales volume of new energy vehicles will exceed 500000 in 2020, making it a leader in the industry; BYD automobile company developed Qin with dual-mode hybrid system in 2013. In addition, there are domestic hybrid vehicles such as Chery A5 BSG hybrid vehicle and FAW Pentium B70 hybrid vehicle. However, due to the lack of technology, China’s hybrid vehicle technology is still in the initial stage of development. At present, there is no international level hybrid vehicle with deep hybrid power split.