Sound Quality Evaluation Metrics on Diesel Engines

When people evaluate the engine NVH, they are not only mentioning whether the engine is loud or not, they say that is noisy or quiet. The difference between these two comments is the way they quantify the engine NVH, from the noise level or the sound quality. Lots of engineers used objective tools to quantify engine sound quality performance for years. In this paper, we would like to propose a novel sound quality matrix for the diesel engine which includes loudness, sharpness, mid-frequency, and high-frequency knocking parameters to perform the sound quality evaluation. In addition, an application case is described in this paper to demonstrate the usage of the new matrix.