Valve Motion Measurements on Motorbike Cylinder Heads using High Speed Laser Vibrometer

This work deals with valve motion measurements on cylinder heads of Ducati racing motorbikes, by means of high speed laser Doppler vibrometer. The experimental apparatus is described and some measurement results are presented. The results confirm that the effects of the dynamic phenomena are very important, especially at high speeds, and that the dynamic response gets worse with the increment of backlashes in the cam kinematic pairs. In addition, the measurements make it possible to analyse the valve bumping phenomena. The information retrieved from measurements provides insight into the cam system dynamics and helps the development of elastodynamic predictive models.