Experimental and Numerical Analysis of Charge Motion Characteristics Depending on Intake Valves Actuation Strategies

摘要

This present work is aimed to the analysis of the possible advantages that could be obtained exploiting Variable Valve Actuation strategies in a high-performance engine head. A set of experimental tests was carried out to obtain maps of the discharge, tumble and swirl coefficients, at any combination of asymmetric lifts of the two intake valves. The results show that asymmetric strategies could allow engine part- load operation characterized by enhanced tumble/swirl generation, while keeping the same effective flow area of conventional two valves symmetric lift. Numerical simulations allowed a deeper understanding of the tumble motion characteristics at different lift combinations, and in particular for asymmetric low lifts cases where the lack of the typical abrupt tumble rising zone was noted.