Mechanical Variable Valve Actuation Systems for Motorcycle Engines

This paper summarizes the results of design of new mechanical variable valve actuation (hereafter VVA) systems, developed for high performance motorcycle engines, at University of Napoli Federico II, Department of Industrial Engineering-Section Mechanics and Energy (hereafter DiME). In addition to a first simple (and limited) system used just as a model for the previous analysis, the work has evolved through three basic steps leading to three types of VVA systems, all mechanical systems (as defined in literature and described later). The study has been conducted implementing a numerical procedure specifically designed to determine cam profile and kinematic and dynamic characteristics of the whole system, starting from some data (as described in the paper). The model has been validated against the conventional timing system using kinematic simulations. Results of the numerical procedure verify the validity of the VVA systems and particularly a better performance of the last one, in spite of its higher complexity.