Vehicle driving cycle is a time-speed curve used to describe vehicle driving rules. The research and development of vehicle driving cycle not only provide theoretical basis for the test of vehicle fuel's economy and pollutant emission level, but also guide the design and development of new models in the future. This paper adopts the actual driving data of light vehicles in Fuzhou City, Fujian Province collected by China Automotive Technology Research Center (CATC) through the data collection system, and analyzes and verifies the new data after standardized dimension reduction by combining the global K-means clustering and Markov chain principle. The specific work is divided into the following parts: 1. The global K-means clustering algorithm adopted to cluster the kinematic segment database after standardized dimension reduction; 2. Markov chain is applied to construct the working condition diagram. The basic principle of this method is to regard the short-stroke speed-time sequence as a complete random process, divide the speed intervals by lines, each of which represents a different speed state, and convert the speed into a speed state, so that the speed-time sequence becomes a state-time sequence. Since the next state is only related to the current one, a group of random state sequences can be randomly generated by the program as long as the transition probability between two adjacent states is determined and the matrix of state transition probability is established. 3. The state sequence is converted into a speed sequence, and finally a set of driving cycle conforming to the spatial characteristics of the samples is obtained.

Compared with traditional vehicles, new energy vehicles have more prominent environmental advantages. In order to promote the technological development of new energy vehicles, the government have given great support in this field. New energy vehicles are widely used in the transportation industry of various countries in the 21st century, which not only saves energy and protects environment, but also effectively promotes the development of China's transportation industry. At present, the main energy sources used by new energy vehicles are electric power and clean fuels. To ensure the normal running, attention should be paid to innovating technological modes and analyzing performance, which is the topic of this paper.

With the further development of the society, the economic level of Chinese residents is gradually improving. Under such circumstances, the number of automobiles and their usage are increasing as well. As a kind of mechanical equipment, there will be many application faults of the automobile after long-term use. Only by solving the faults can automobiles be restarted and run stably for a long time. Based on this, this paper focuses on automobile maintenance, analyzes the principle of engine cooling system, and studies the diagnosis and maintenance methods of this kind of fault, trying to provide some reference value for the further discussion and research in this field.

With the continuous development of the society and improvement of the national economic level in China, people's life has undergone enormous changes in many aspects, the demand for transportation has gradually increased, and various transportation modes have emerged. At present, environmental pollution is becoming increasingly serious as automobile exhaust has become one of the main factors of air pollution. Under such circumstances, new energy vehicles have emerged and become increasingly popular in society, actively responding to the scientific and sustainable development strategy called for by China's government. This paper mainly studies the maintenance technology of new energy vehicle engines, hoping to provide help for the development of China's new energy vehicle industry.

Hybrid electric vehicles (HEV) are the most industrialized and marketable in electric vehicles. Referring to the basic structure and parameters adopted by PRIUS Hybrid of Toyota, this paper puts forward an optimization scheme of HEV. The parameters and type selection of power components are obtained according to the vehicle's dynamic formula. The optimized hybrid power system is built and simulated through the simulation platform AVL Cruise. Then the obtained economic and dynamic parameters are analyzed and compared with the original performance parameters, verifying that the optimized system has better performance.