Subjective Evaluation Of Engine And Vehicle Sound Quality And Road Traffic Noise Prediction, Analysis

"Energy and Environment"are the two great problems of the century, with the speedup of people's life, development of society migration, and need of more comfortable life quality, beside of the standard of energy saving, safety, and pollution reducing, the demand of riding comfort becomes more and more important. In addition, the increase of vehicle retainment quantity and city population makes the problem of traffic noise pollution, which is especially severe in the inhabitation area beside of road.The paper aims at three different types of vehicle. After the noises were measured and stored at various speed conditions, then were evaluated by listeners adopting the method of paired comparison, the score of each noise sample can be obtained finally. For the noise samples the physical parameters were distilled: loudness, sharpness, fluctuation, periodicity and kurtsis. Using the method and theory of multiple statistics, the relationship between objective physical parameters and subjective evaluation scores was analyzed, and then the psychological evaluation model can be built up. The result shows that loudness is the most important factor, kurtosis and periodicity are the next, in which the weighing factors of periodicity and fluctuation are negative, and this indicates that the vehicle sound quality will be improved with the increase of periodicity and fluctuation. The based process and method of the model are use for reference and valuable for the study of the sound quality problem of other vehicle types.City road traffic noise is influenced by many factors, including the source and the transmitting path, in which the traffic volume, vehicle speed and ratio of heavy vehicle are the dominating factors. The paper predicted road traffic noise and analyzed environment influence using simplified equivalent vehicle volume model, the experiment result shows that the mean value between the prediction results using the model and measured values is 0.609dB(A), and the maximal difference value is 1.321dB(A). The model simplified the prediction process greatly and is simple and convenient to use.Hence the more usual control means of traffic noise is the adoption of sound barrier and sound insulation door and window. The paper carried through numerical calculation and FEM/BEM simulation, sound barrier soniferous loss mainly rest with distance difference and sound frequency, for sound insulation door and window there is a more definitive factor: sound impedance of per unit area other than the incidence angle. For thick plate, sound impedance has become the most importance factor. Also the experiment analysis and validation is proceeded, the, the outcome shows that the numerical computation can satisfy the engineering requirement in spite of the difference between numerical calculation and experiment, also the computation method is far more advantaged than experiment in practical condition, expenditure and alteration of scheme etc.There isn't a full integrated system for prediction, analysis and evaluation of road traffic noise, foreign software is adopted for traffic noise. The paper developed a full integrated system for prediction, analysis and evaluation of road traffic noise on the basis of testing and analyzing, revised the diversified prediction models combined with our practical condition. The measurement results show that the modified CRTN and RLS90 model are more appropriate in road traffic noise prediction relatively.