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This paper presents a newly developed quasi-dimensional multi-zone dual fuel combustion model, which has been integrated within the commercial engine system simulation framework. Model is based on the modified Multi-Zone Combustion Model and Fractal Combustion Model. Modified Multi-Zone Combustion Model handles the part of the combustion process that is governed by the mixing-controlled combustion, while the modified Fractal Combustion Model handles the part that is governed by the flame propagation through the combustion chamber. The developed quasi-dimensional dual fuel combustion model features phenomenological description of spray processes, i.e. liquid spray break-up, fresh charge entrainment, droplet heat-up and evaporation process. In order to capture the chemical effects on the ignition delay, special ignition delay table has been made.

In the paper the operation of a turbocharged dual fuel engine at mid-high load is investigated on a single cylinder experimental engine complemented by a full 0D/1D simulation model that provides boundary conditions for the experiment and full engine system results. When duel fuel combustion mode is used on a turbocharged engine with the variable geometry turbocharger, the mid-high load operating points can be obtained with number of different combinations of intake pressure and excess air ratio. Besides the impact on combustion, the specific combination of intake pressure - excess air ratio has also impact on the exhaust back pressure caused by the turbocharger and consequently on the obtained brake efficiency. Additionally, the dual fuel combustion is influenced by natural gas mass fraction and start of injection of diesel fuel and the search for the optimal solution could be a challenging task.

Exhaust gas recirculation (EGR) is a proven strategy for the reduction of NOX emissions in spark ignited (SI) engines and compression ignition engines, especially in lean burn conditions where the increase of thermal efficiency is obtained. The dilution level of the mixture with EGR is in a conventional SI engine limited by the increase of combustion instability (CoV IMEP). A possible method to extend the EGR dilution level and ensure stable combustion is the implementation of an active pre-chamber combustion system. The pre-chamber spark ignited (PCSI) engine enables fast and stable combustion of lean mixtures in the main chamber by utilizing high ignition energy of multiple flame jets penetrating from the pre-chamber to the main chamber. In this paper, as an initial research step, a numerical analysis is performed by employing the 0D/1D simulation model, validated with the initial experimental and 3D-CFD results.