In the paper, the potentialities offered by an advanced valve lift design are numerically analyzed. In particular, the study is carried out by a 1D approach and regards the characterization of a VVA strategy named "pre-lift" applied to a downsized turbocharged four-cylinder engine. The pre-lift consists of a small, almost constant lift of the intake valve during the exhaust stroke, so to increase the valves overlapping. The results show a benefit on the fuel economy and on the gas-dynamic noise at part load and a substantial increase in the delivered torque at full load, while preserving the fuel consumption.
De Bellis, V., Gimelli, A., & Muccillo, M. (2015). Effects of Pre-Lift intake valve strategies on the performance of a DISI VVA turbocharged engine at part and full load operation. In Energy Procedia (Vol. 81, pp. 874–882). Elsevier Ltd. https://doi.org/10.1016/j.egypro.2015.12.141