Electromagnetic Compatibility Study Of ECU For Gasoline Direct Injection Engine

Faced with the growing energy crisis and stringent emissions regulations,Gasoline direct injection（GDI）engine is one of the main directions of development ofthe vehicle because of its advantage of power and economy. Reliable electrical controlsystem is a necessary condition for achieving its superiority, With increasinglycomplex of electronic control unit（ECU） and it’s harsh environment, the ECU facesenormous challenges of Electromagnetic Compatibility （EMC）. This paper has anEMC study of ECU for GDI engine and lays the foundation for design of stable andreliable ECU which meets national standards. The main content and results of thispaper are as follow:Fist, according to the need of the design of EMC, chose the simulation platformabout circuit and magnetic field, and developed the hardware in-the-loop simulationas ECU functional verification platform.Second, based on the environment of each module of ECU, this paper analyzedits main external interference and internal interference, and design ECU combinationwith the EMC design experience and measures. And the main research is about EMCdesign for injector module which is the major sources of internal interference. To meetthe response characteristics of high pressure injector solenoid valve in GDI engine,the high-low voltage time-sharing driving module which is made up of a boostconverter circuit and a PWM-Modulation driving circuit was developed and designed.And this paper optimized the module from the component selection, schematic design andPCB layout.Based on Multisim, optimized the circuit of the gate of MOSFET, and combinedwith the time response requirements of the boost converter circuit, optimized theparameter values of the boost converter circuit, and the test results show that,1) thegate voltage can be quickly reduced to zero and the switch can be closed quickly,2) the boostconverter circuit can get the required voltage within20ms, and its maximumfluctuating is less than10%with renewing-time is1.5ms. The circuit can getPeak&Hold driving current and it takes within200μs for the current rising from0A topeak current16A, which meets the strict requirements of the injector driving modulefor GDI engine.In addition, based on the SIWAVE, computed the near-field radiation of boostconverter circuit PCB. According to the simulation results, optimized the PCB, and the result of near-field simulation shows that, the near-field radiation which is causedby the grounding layout has a large degree of inhibition, and the radiation area isdecreased too. Combined with the independent development of HIL system and usedEMSCAN to test the ECU, and the results show that, the radiation field strength andradiation area of PCB within a controllable range, and meet the EMI requirements.The results provide a basis for further optimization.