Sound quality change of the automotive engine noise by variation of engine oil condition

Sometimes, engine oil is referred to as a factor that affects engine sound and driving feeling. To investigate the difference of engine noise according to the engine oil conditions in the viewpoint of sound quality, the interior and exterior sound of middle-class sedan with gasoline engine was compared under the different oil conditions. Objective analysis was conducted to find the existence of any appreciable change in psychoacoustic attributes. Loudness, sharpness, and roughness are observed as the important sound quality metrics. It was observed that the noise differences were induced by the oil property, temperature and used time. Basically, the dramatic difference is rarely observed with the difference of initial property of oil. According to change of temperature, lower loudness is observed at the high temperature condition. Comparing new and used oils, the relatively high loudness was observed at idle condition after replacing oil, especially in the low frequency range.