Aiming at meeting the stringent regulations imposed by the EU and other legislators in the transport sector, various advanced combustion modes for Internal Combustion Engines (ICEs) are currently under investigation. Among those, Homogeneous Charge Compression Ignition (HCCI) appears a promising solution, simultaneously reducing pollutant emission and enhancing thermal efficiency.
Hence, to simulate HCCI combustion mode, a general multi-zone model has been developed and implemented through user coding into a commercial software (GT-Power™). This model is based on a control mass Lagrangian multi-zone approach, and it incorporates a procedure based on an off-line tabulation of chemical kinetics (Tabulated Kinetic of Ignition - TKI). It performs an accurate and fast prediction of the air/fuel mixture auto-ignition, combining the accuracy of detailed chemistry with a lighter computational effort.
The tabulated procedure is preliminarily verified against the results of a conventional chemical kinetics solver applied to a constant-volume homogeneous reactor and to a single-zone engine cycle simulation.
Subsequently, the multi-zone model is applied to reproduce experimental data taken from literature in engines operated with different fuels (conventional gasoline, hydrogen, methane, and n-heptane), for various temperatures at IVC, air/fuel ratios, and EGR levels. Model accuracy is verified on both experimental pressure traces, rate of heat release, and noxious emissions.
The numerical results showed good agreement with experimental data without the need for case-by-case tuning. The methodology proved to be a reliable tool to investigate the operation of a HCCI engine, to be applied in the development of new engine architecture working under this advanced combustion mode.