Graf, B., Hubmann, C., Resch, M., and Mehrgou, M., "A Hybrid Development Process for NVH Optimization and Sound Engineering Considering the Future Pass-by Homologation Demands," SAE Int. J. Veh. Dyn., Stab., and NVH 1(1):2017, doi:10.4271/2016-32-0043.
Beside hard facts as performance, emissions and fuel consumption especially the brand specific attributes such as styling and sound are very emotional, unique selling prepositions. To develop these emotional characters, within the given boundary conditions of the future pass-by regulation, it is necessary to define them at the very beginning of the project and to follow a consequent development process. The following paper shows examples of motorcycle NVH development work on noise cleaning and sound engineering using a hybrid development process combining front loading, simulation and testing.One of the discussed solutions is the investigation of a piston pin offset in combination with a crankshaft offset for the reduction of friction. The optimization of piston slap noise as a result of the piston secondary motion was performed by simulation.As another example a simulation based development was performed for the exhaust system layout. A prerequisite for the optimization of the exhaust orifice sound was the definition and artificial generation of the target sound. The challenge for the target sound development was to comply with the future pass-by noise legislations and to feature a distinctive, brand specific sound.A third example in terms of front loading shows the NVH concept design review and evaluation of different cover solutions with a combination of measurement and simulation to avoid disturbing mechanical noise phenomena originating from the engine and gearbox.The outlined examples demonstrate the flexibility and capability of the hybrid development process.