| Along with the development of world economy, people’s living standard has been improving, so that the demand for cars in every family is also increasing year by year. Since the 20 th century ending, the auto output in China has been rising rapidly. By the end of 2014, the national vehicle population reached 264 million, of which 154 million cars. In 2014, small passenger cars amounted to 117 million. The volume of auto production and sales were completed in 2015 with 24,503,300 and 24,597,600, a record high, compared to an increase of 3.3% and 4.7%, respectively, last year. With a steady growth trend, the production and sales growth rate decreased by 4% and 2.2% respectively, comparing with last year. Where the development of commercial vehicles has been seen as a barometer of economic development in the automotive sector, in 2015 the production and sales of commercial vehicles were completed with 3,423,900 and 3,451,300 respectively, compared to the decline of 10% and 9% respectively, last year. There are many different types of electric pump in the car structure, which can be divided according to use: electric lubrication pump, electric fuel pumps, electric air pumps, and electric pumping pump. Wherein the electric fuel pump is the fuel control system with computer-controlled cars in important parts, wearing parts and is therefore in great demand.The electric fuel pump is mainly composed of three parts, the pump body, the DC motor and the outer shell, the working principle of which is: after power DC motor driven rotary pump fuel from the inlet suction, the internal flow through the electric fuel pump, and then forced out from the oil outlet to the fuel supply system. Due to the relatively poor domestic diesel oil, high sulfur and moisture content results in the structure of the electric fuel pump motor in a DC electric fuel pump in the whole structure of the most prone to failure of components. Therefore, this paper takes DC motors as the research object, in-depth study of Brushless DC motors; optimize the design of electric fuel pump, so that it is more suitable to the current stage of domestic diesel oil and diesel engine fuel system needs.In this paper, by reading a lot of literature, the author has a more comprehensive understanding with the development, status & trends of the permanent magnet motor and technologies related. Meanwhile in actual work we replace the brushless DC motor structure with the brush DC motor structure, and the implementation of product development and quality improvement process also has accumulated a lot of experience. On this basis, the author analyzes the mathematical model of a brushless DC motor, establishes a simulation test platform based on the FT3106 integrated control chip. Moreover we build peripheral circuits to optimize brushless DC motor control system parameters, and the design of software & hardware control system accesses to valuable research results. Learning basic theory knowledge and the applications design of a brushless DC motor led the team to achieve technology products eventually. We make full use of laboratories and vehicle test resources, and carry out in-depth research on the function, mechanical reliability& electromagnetic compatible reliability of the brushless DC motor structure for the electric pump assembly. In addition, the fault analysis of products solves the problems in the practical application process.Finally, on the benefit of the project team’s efforts, we successfully have developed a multifunctional electric fuel oil pump for the low pressure fuel system domestic diesel engine, which gets a wide range of applications now. We have accumulated a l lot of experience in the design and development of automotive electronics and electrical products, and have summarized a set of reasonable development process and specifications for similar products design.The main contents of this paper include:(1) The structure difference between brushed DC motors and brushless DC motors.(2) The principle, the mathematical model and the basic characteristics under certain parameters of brushless DC motors.(3) The hardware and software design of the control system for electric fuel pump.(4) Research and analysis on the position of a brushless DC motor & the current detection and control system.(5) The reliability of an electric fuel pump assembly; the impacts on the reliability of the diesel engine start-up performance.(6) The lab validations for the function and reliability of the electric fuel pump.This paper carried out a lot of research on theoretical analysis, computer simulation, software & hardware platform design and product testing, and finally some meaningful experiences and conclusions are obtained for the further research of the subject. |
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