Tanaka, K., Sugita, H., Saito, H., and Sekita, M., "Design Method of Motorcycle Exhaust Sound Fitting to Vehicle Concept Regardless of Engine Configurations," SAE Technical Paper 2014-32-0121, 2014, doi:10.4271/2014-32-0121.
Recently, it has been widely practiced in motorcycle developments that the same type of engine is commonly applied to various vehicle categories. Accordingly, it is drawing more attention to develop the methodology for creating the best suitable sound for each individual vehicle category regardless of restriction from the engine configurations. In our study, we aimed to establish a procedure to control exhaust sounds beyond the borders across the inherent sound qualities originated from their engine configurations.Firstly, we conducted subjective tests in order to extract essential factors, depicted by adjectives that appear in verbal expressions commonly used to illustrate sound qualities in general. The results enabled us to conduct quantitative evaluations of the exhaust sound qualities of various motorcycles. Next, we clarified the relationships among the individual factors of sound qualities under our study and physical parameters in waveforms of the sounds. Finally, we tried to design the target sound quality having required physical parameters by using a one-dimensional simulation tool. The established method was applied to a cruiser type of motorcycle with V-four engine to which it was sought to have enhanced V-twin-like feature of “pulse-feeling” sound. From the results we obtained, it was successfully proven that the method we established through the study processes was potentially useful in practical applications.