A comparison study of different NVO strategies in a diesel HCCI engine using 3D CFD

摘要

A three-dimensional modeling was carried out to investigate effects of negative valve overlap (NVO) on gas exchange and fuel-air mixing processes in a diesel homogeneous charge compression ignition (HCCI) engine with early fuel injection. Four cases with different EVO and IVC were calculated to compare the effects of the begin time and the end time of the gas exchange process on HCCI engines with NVO firstly. And then three NVO strategies with different maximum valve lift and valve timing were compared to make it clear that the effects of valve lift and valve timing on retaining residual and control of the in-cylinder temperature, and their further influences on air motion and mixture preparation process.