A Model for the Elastodynamic Analysis of the Geared Timing System of a Motorbike Engine.

This work deals with the elastodynamic model of the geared valvetrain of a four-cylinder “L” engine of a Ducati racing motorbike. The model, which is an evolution of the author’s research, is obtained as a combination of lumped parameter and finite element parts. The model is able to inspect the dynamic behaviour of both the geartrain and the cam-valve mechanisms. The paper mainly describes the model validation process that is based on several experimental tests and it is achieved by means of different steps. The information obtained from the validation stages have been finally employed for the tuning of the combined lumped/finite element model of the geared timing system. The experimental procedures are also illustrated, together with some details on the signal treatments. The comparison between simulations an experiments shows that the effectiveness of the model is satisfactorily assessed, thus permitting the use of the model as a tool for the design optimisation of the motorbike timing system. The results obtained for the competitive motorbike engine can also be utilized for common production engines, where conformity to vibration and noise standards must be fulfilled.