Abstract
Traditional acoustic evaluation of a diesel engine generally uses the A-weighted sound pressure level (AWSPL) and radiated sound power to assess the noise of an engine prototype present in an experiment. However, this cannot accurately and comprehensively reflect the auditory senses of human subjects during the simulation stage. To overcome such shortage, the Moore–Glasberg loudness and sharpness approach is applied to evaluate and improve the sound quality (SQ) of a 16 V-type marine diesel engine, and synthesizing noise audio files. Through finite element (FE) simulations, the modes of the engine’s block and the average vibrational velocity of the entire engine surface were calculated and compared with the test results. By further applying an automatically matched layer (AML) approach, the engine-radiated sound pressure level (SPL) and sound power contributions of all engine parts were obtained. By analyzing the Moore–Glasberg loudness and sharpness characteristics of three critical sound field points, an improvement strategy of the oil sump was then proposed. After improvement, both the loudness and sharpness decreased significantly. To verify the objective SQ evaluation results, ten noise audio clips of the diesel engine were then synthesized and tested. The subjective evaluation results were in accordance with the simulated analysis. Therefore, the proposed approach to analyze and improve the SQ of a diesel engine is reliable and effective.
Highlights
Due to the high-speed and power development trend of marine diesel engines, their vibration and noise issues are becoming more significant
Using the traditional A-weighted sound pressure level (AWSPL) and radiated sound power metrics sometimes leads to a phenomenon in which the evaluation results of some noise may be acceptable but is still disturbing to human subjects
Because the sound quality (SQ) evaluation was based on human auditory perception, to verify the improvement effect and psychoacoustic analysis results of a diesel engine during the simulation stage, 10 audio clips from field point Pa before and after improvement were synthesized for a subjective evaluation
Summary
Due to the high-speed and power development trend of marine diesel engines, their vibration and noise issues are becoming more significant. The aim of this study is to evaluate and improve the SQ of a 16 V-type marine diesel engine based on the simulation and test to verify the improvement effects. Both loudness and sharpness are important objective evaluation parameters to investigate the SQ. Ishibashi et al noise [9] compared the frequency sound pressure (SPL) with the Zwicker. Yoon et al [10] compared the Zwicker specific loudness of passing noise that they have a strong correlation. Critical band with the equivalent rectangular bandwidth (ERB) They did not analyze the they did not analyze the Moore–Glasberg specific loudness distribution characteristics in. When calculating the excitation level, the Moore–Glasberg model divides the human auditory frequency range (20–20,000 Hz) into 372 sub-bands which are from 1.8 to 38.9 Cams with an interval frequency range (20–20,000 Hz) into 372 sub-bands which are from 1.8 to 38.9 Cams with an interval of of
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