商用车柴油机加速声品质主客观评价研究

Research on Commercial Vehicle Diesel Engine Sound Quality Subjective and Objective Evaluation During Acceleration

以某6缸商用车柴油机为对象,研究其不同扭矩和起始转速下的加速声品质评价方法.以心理声学参量响度、尖锐度、粗糙度、抖动度和语义清晰度作为初级客观评价指标,将初级指标随时间的变化率作为二级评价指标,构建两级声品质评价指标体系进行声品质客观评价;采用成对比较法对39组声音样本进行评审团主观评价,利用多元线性回归方法建立柴油机加速声品质预测模型,并进行了精确度验证;分析了影响柴油机加速声品质的因素.研究显示,模型的预测结果和主观评价结果的平均偏差率为15.72%,说明基于新的客观评价指标体系建立预测模型对加速工况下的柴油机声品质有较好的预测能力;响度是影响发动机声品质的主要客观指标,扭矩和转速的增加会导致声品质的下降,转速变化的快慢程度也对柴油机声品质有较大影响.

In this study,we used a six-cylinder commercial vehicle diesel engine to evaluate the sound quality of acceleration noise under different torque and initial engine speed conditions.To ensure the objective evaluation of sound quality,we constructed a two-level index system in which loudness,sharpness,roughness,fluctuation,and articulation were included in the primary level.We derived the time-dependent change rates of the primary indices as secondary indices.We performed a subjective jury test on 39 noise samples using the pairwise comparison method.Using multiple linear regressions,we then established and verified the accuracy of a prediction model for the acceleration sound quality of the diesel engine.Our analysis of the factors affecting the acceleration sound quality of the diesel engine shows the average deviation between the predicted and subjective evaluation results to be 15.72%.This indicates that our prediction model based on the new objective evaluation index system has better prediction ability of diesel engine sound quality under acceleration conditions.We determined that loudness is the main objective parameter affecting engine sound quality,and sound quality decreases with increasing engine load and speed.In addition,we determined that the acceleration rate has considerable effects on the sound quality of diesel engine.