CFD study of a CI engine powered in the dual-fuel mode with syngas and waste vegetable oil

Syngas production from biomass gasification and its use in combined heat and power (CHP) generation systems is a feasible alternative to traditional fuels in Internal Combustion Engines (ICEs), although its quality is poorer in terms of calorific value and energy density. Therefore, a viable option for its exploitation can be assured if ICEs operate in dual-fuel (DF) mode, where employing non-edible oils (as Waste Vegetable Oils, WVO) as a further residual material may solve issues related both to the utilization of diesel fuels and to the high costs for biodiesel production. The practice promotes a virtuous circle to enhance material recovery without disposal. A combined experimental-numerical activity for the analysis of the performances of a Compression Ignition (CI) engine in the DF mode with syngas and WVO is here presented. An appropriate pre-heating system is mounted on the engine injection line to reduce the WVO viscosity. Experimental data collected in terms of in-cylinder pressure cycle, heat release rates and main pollutants at different loads are used to validate a properly developed three-dimensional (3D) Computational Fluid Dynamics (CFD) model, that helps investigating the detail of the syngas fuelling on power output and emissions.