Due to the rapid growth of the car manufacturing industry worldwide,the production of cars and the ownership of cars have increased sharply.Vehicles provide a lot of convenience for our lives and create a lot of difficulties.With the improvement of people's living conditions,their demand for vehicle reliability,comfort and other aspects will also increase,which further prompts our R & D workers in the car industry to use various new types of science and technology to improve the reliability of all aspects of the vehicle to meet the needs of customers for vehicle technology.