| Electromagnetic interference (EMI) fields inside the automobile result from many sources such as petrolic engine ignition system, generator system, electromotor, and all kinds of relay switching. The primary EMI source is the engine ignition system. On one hand, the EMI produced by the petrolic ignition system is high intensity and has a broad-band spectrum. On the other hand, with the rapid development of automotive electronic technology, electronic components and modules are widely used in automobile nowadays, and the working voltages of electronic devices gradually decrease, it makes these devices more vulnerable to EMI. Therefore it is of great theoretical significance and practical value to investigate the electromagnetic compatibility (EMC) of petrolic ignition system. Supported by the Natural Science Foundation Project of Chongqing, China (NO. CSTC, 2006BA6015), the experiment and simulation method for the EMI of automotive ignition system is thoroughly investigated in this dissertation. The main contents are listed below:①Based on Field-Circuit combination method, the conducted electromagnetic disturbance of igniton system is simulated. According to each of the ignition system component's electromagnetic properties to establish the equivalent circuits model for each component, and using electromagnetic numerical methods to calculate the physical model to obtain the electrical parameter for each circuit model, and then based on each circuit model to build the conducted electromagnetic disturbance model for the entire ignition system. Simulation and test results verify the correctness of the simulation.②The radiation electromagnetic disturbance of ignition system is simulated based on the finite difference time domain (FDTD) method. A three-dimensional model of the ignition system and the whole vehicle suitable for electromagnetic simulation is built using CAD techniques. Considering the transient interference current on the primary and ignition wire as the dominant radiation source and using the FDTD method, the radiation electromagnetic disturbance of the ignition system on platform, and inside the vehicle are calculated. Simulation and test results verify the correctness of the simulation.③The prediction of crosstalk coupling among interconnection wires is proposed using artificial neural networks. The input prediction features consist of those EMI parameters that have the influence on the crosstalk coupling. Using the back propagation (BP) training algorithm, the relationship between the input prediction features and the output crosstalk coupling response of the interconnection wires can be constructed. The learning sample set is obtained by the FDTD method. The effectiveness of the proposed method is verified by comparing the prediction values of the BP network and the test sample values. Finally, a wiring arrangement method is proposed for suppressing the crosstalk coupling inside the automobile.④The simulation method of the radiation EMI fields penetrating through the apertures and connection cables that interfered the electronic equipment is investigated. Based on the theory of aperture diffraction, field excitation to cable and transmission line theory with distributing source, the mathematical prediction model of the radiation EMI fields through the equipment aperture is described. Moreover, an equivalent substitution model for field to wire coupling of the radiation EMI fields coupling to the equipment external cable is presented. Finally, simulation was conducted on the impact of the incidence angle, the aperture size, and the cable length of the radiation EMI on the coupling interference voltage.⑤Electromagnetic disturbance suppressing methods of automotive ignition system are theoretical researched and some suppressing methods are also measured. Theoretical analysis and experimental results show that selection of resistor-type spark plug and ignition wire , add the ferrite and filter could reduce the electromagnetic disturbance of ignition system.
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