2025 Volume 41 Pages 140-145
In pursuit of a carbon-neutral society, Mazda is working on the development of an ideal engine through a multi-solution strategy that balances electrification with internal combustion engines. Among these efforts, to provide customers with the unique value of 'driving pleasure,' Mazda is focusing on achieving engine sound that offers both quietness and exhilaration. However, piston slap noise disrupts the desirable engine sound, necessitating the establishment of efficient prediction methods for piston slap noise. Previous piston slap noise predictions using simulation models evaluated indicators such as the piston's kinetic energy and the cylinder block's wall vibrations, but these have not always aligned with auditory evaluations. In this study, we quantified the exceedance value using cylinder block vibrations and engine background noise (masking vibration) to establish an effective detection method for piston slap based on a predictive model. As a result, a good correlation with auditory evaluations was confirmed. Consequently, this approach enabled the prediction of piston slap noise in newly developed engines.
