VARIABLE VALVE ACTUATION FOR ADVANCED POWERTRAINS

摘要

We review variable valve actuation (VVA) concepts and also present the results of our work in the creative synthesis of these devices. We begin with a comprehensive survey of existing VVA devices. We then describe our work on four VVA concepts which we have explored in considerable detail. These include hydraulic lost-motion variable-lift systems, in both the direct acting and the roller-finger-follower configurations, several valve deactivation mechanisms with unique features, a variable valve-lift mechanism, and a variable-lift and duration concept. These devices differ in their complexity and versatility but offer a spectrum of design solutions applicable to a range of products. The strengths and weaknesses of these different approaches are discussed and analyzed, and some test results are presented.