Due to the difference in cetane number between e-fuel, a synthetic fuel made from CO2, and diesel, pre-ignition is an issue in PCCI combustion, where the fuel is sprayed early. Therefore, we aimed to lower the effective compression ratio and retard the ignition timing by using LIVC (Late Intake Valve Closing) with a VVT mechanism. We created a surrogate model of e-fuel using the 3DCFD tool ANSYS Forte and investigated the effects of LIVC and the presence or absence of EGR under PCCI combustion conditions. As a result, when LIVC was performed, the ignition timing was retarded, improving engine performance such as thermal efficiency and IMEP. Furthermore, NOx emissions could be reduced by improving the ignition timing. We also found that further reductions in NOx emissions could be achieved by using EGR.
Matsuzaki et al. (Wed,) studied this question.