Research On Electromagnetic Pulse Effects Of Vehicle Engine System

With the research and application of electromagnetic pulse device,the vehicle's mobility and driving safety is under seriously threat.As the most important unit,engine system is equipped with many electronic devices,which can be disturbed by EMP(electromagnetic pulse).Then cause defection of some functions even the hardware damage.Deeply research on electromagnetic pulse effects of engine system is meaningful for vehicle electromagnetic protection design.Acquiring the surrounding electromagnetic environment of engine system is the base of effect research.However,for a real vehicle,its shell is irregular.And,engine cabin is filled with metal equipment with complex structure.All of these factors result in difficulty to simulation modeling for engine cabin electromagnetic environment calculate.EMP radiation test is the most effective method to understand engine electromagnetic effects,but it's difficult to acquire engine failure signal under strong radiation fields,which is disadvantage for failure analyze.So,it's difficult to find out the critical failure reason of engine system in different operating states under attack of EMP.Considering the high cost of system EMP radiation test,the sample quantity is really limited.And there are many uncertain factors in EMP radiation test,which lead to inaccuracy of engine failure probability assessment.In this paper,the EMP effect is researched with Jetta engine system from three aspects: electromagnetic environment analyze of engine cabin,sensitive test and failure reason analyze of engine system,electromagnetic susceptibility assessment of engine subsystem.The main contributions and innovative points of this dissertation are listed as follows:(1)Find out the distribution characteristics of peak values of electric field strength through simulation with CST MS STUDIO,which provide valuable electric field environmental data for engine electromagnetic protection design and susceptibility assessment.Balancing the real structure of vehicles and computer hardware resources,we establish a engine cabin simplified model containing shell,main metallic devices,and chasis.Calculate the peak values of electric field strength in key location of engine cabin under EMP radiation.With statistical analysis,we get the distribution characteristics of peak value of electric field strength in engine cabin by set 461 observing point and variation of peak value with different incidence parameters.Results show that the peak value of electric field strength in engine cabin accord with Rayleigh distribution,and the peak value of electric field strength accord with normal distribution in different EMP incidence parameter.(2)Design and built a measurement system to monitor engine cables signals in real-time,which can operates under strong electromagnetic radiation environment.Engine EMP effect test are performed in component level and system level.For component level,pulse injection testing platform is established,and the susceptibility threshold of hall speed sensor and electronic throttle are acquired through observe breakdown signal waveform.Furthermore,the relationship between susceptibility threshold and pulse parameters is observed.For system level,the response of engine system with HPM(high power microwave)is observed through radiation test.Finally,the failure reasons of engine system with EMP are analyzed from signal aspect.(3)A modeling and parameter determining method based on BN(Bayesian Networks)for engine subsystem EMP susceptibility assessment is proposed.All uncertain factors,for example,different directions of incident wave,component failure threshold distributes,are considered using probability theory in order to remedy deficiencies of susceptibility assessment based on effect test with limited samples.First,According to the structure of engine subsystem,the FT(fault tree)model is built.And the coupling with EMP is analyzed using EMT(electromagnetic topology).Then,the BN assessment model is built integrating the FT and EMT,also the probability acquiring of BN nodes is discussed.Finally,the susceptibility assessment of electronic throttle against HEMP(high-altitude electromagnetic pulse)is taken as an example to illustrate the modeling and probability calculating process,which verify the effectiveness of BN assessment model.