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엔진 사운드 분석을 통한 Formula SAE 참가 차량의 주행 특성 분석
김의열(Euiyoul Kim) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
In order to analyze the vehicle dynamics, we have applied a variety of the analysis method to the vehicle. generally, most vehicle dynamics data come from using the sophisticated equipment. so, it is difficult and expensive for students to measure the vehicle dynamics. is there more convenient method without using the sophisticated equipment? In this case, how about using the sound analysis? In order to find whether it is possible or not. I have applied FFT theory to the engine sound of Formula SAE. the same technique have already been used to find the problem of any complicated piece of machinery. In conclusion, from this analysis, we can get not only engine performance, but driver's technique and team's strategy. and it is possible to obtain more information efficiently and inexpensively than other methods.
김의열(Euiyoul Kim),이상권(Sangkwon Lee) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
Fuel cell electric vehicles have some noise problems due to its air processing unit which is required to feed the ambient air into the fuel cell stack. Discrete-frequency noises are radiated from a centrifugal blower due to rotor-stator interaction. Their fundamental frequency is the blade passing frequency, which is determined by the number of rotor blades and their rotating speed. To reduce such noises, multi-chamber perforated muffler has been designed. In this paper, in order to improve the transmission loss of a perforated muffler, the relationship between the impedance model of a perforated hole and its noise reduction performance is studied, and the applicability of a short-length perforated muffler to air processing unit of fuel cell system is described using acoustic simulation result and experimental data. The acoustic velocity vector across the neck of a perforated hole is very important design factor to optimize the transmission loss of an intake muffler. The suggested short-length perforated muffler is effective on discrete-frequency noises while keeping the volume of intake muffler minimized