20 A Combined Experimental and Numerical Approach for Motorcycle Crank Noise: Experimental Validation

The demands for comfort and a cleaner environment have been increasing for the past years for motorcycle as well as car manufacturers. With the need to decrease the time-to-market, there is a clear drive to apply CAE-based methods in order to evaluate new designs and to propose design changes that solve any identified problems. More specifically, the demands on the comfort of the rider are not only related to ride & handling and vibration levels⁽¹⁾, but also to the noise levels generated by the motorcycle. This paper presents the virtual modeling of one-cylinder engine of a motorcycle that identifies the mechanism behind the generation of an annoying noise. Furthermore, different possible design changes were evaluated in order to solve the problem. A combined experimental and numerical approach was followed to achieve this. Experiments were used to identify important parameters that determine the engine behavior and thus are critical for the modeling of such an engine. In a previous paper ⁽²⁾ the focus is on the modeling while this paper describes that the numerical findings were validated by experimental data and the implementation of design changes on a prototype motorcycle.