Automotive Ignition System Suppression Method Of Electromagnetic Disturbance

Automotive ignition system is the most powerful electromagnetic interference sources of automobile. The research of electromagnetic compatibility has important theoretical meaning and engineering value. Under the support of "Automotive EMC prediction and research of key technologies for electromagnetic interference suppression,"of National Natural Science Foundation (No.50877081), which cooperated with Chang An Automobile under the project "the research of electromagnetic interference suppression measures of car ignition system ". There has new understanding during the process of the study of harassment mechanism in automotive ignition system. In view of the characteristics of the research target, we set up the ignition system simulation platform to testify the effects of Optical isolation circuit, mixed filter circuit, metal shielding, in curbing electromagnetic interference. The tested results will not only guide the modification of ignition system of electromagnetic, but also provide reference to the design of vehicle electromagnetic compatibility.In the thesis, it is believed that the electromagnetic interference is made by radiation and conducted inference of power line to the space and other equipment, other than sparks. Design and made the ignition controller to solve the problem of self-radiation reference of flame-light signal, which will affect the accuracy of the test when using the ignition system simulation platform. Using the Optical isolation circuit to separate electromagnetic interference which made by ignition system to the ECU of the car. Analysing the theory of photoelectric coupling isolation separate electromagnetic interference, as a result to design the experimental circuit and build up the mathematical model of photoelectric coupling isolation. To testify the effectiveness of optical isolation from two aspects experiment and simulation, combining with the characteristic of ferrite filter to analyze the often-used components of the ferrite filter, to choose the suitable components and models. Meanwhile, combine with all the characteristics of electromagnetic interference of ignition system and adopt the EMI composite filter which made up of ferrite common mode choke and polyester film capacitor. A series of professional test will be done to prove the effectiveness of the filter. Design and implement the metal shield box experiment, Faraday shielding experiment, vehicle ignition system wire shielding experiment. To analyze these shielding methods combined with shielding theory, in order to point out what should be noticed in the application of the automobile ignition system and also to identify what kind of shielding methods are not suitable for the automobile ignition system. This thesis will provide guidance to the design of automotive EMC and suppression of electromagnetic disturbance has get value for reference.