Emission modelling is still a timely topic in the engine research community. Soot emission reduction has gained its spotlight among the pollutants-related issues mainly due to the renewed interest in Gasoline Direct Injection. The conjunction of experimental measurements and numerical investigations provides an effective tool to cope with the constant evolution of the emission regulations. Thus, numerical models must be validated over a wide range of engine operating points and fuels. To this aim, the Sectional Method was applied to investigate Particulate Matter and Particle Number produced during combustion in a premixed spark ignition engine using 3D-CFD. Soot-related quantities were investigated for different values of equivalence ratio (from 1.0 up to 1.5) as well as for different fuels. Three different fuel types were examined: a commercial nonoxygenated American gasoline (TIER-2), a commercial Chinese gasoline (CHINA-6) with ethanol 10 %vol and pure Ethanol (E100). A detailed chemistry-based tabulated approach was exploited to compute a dedicated soot library, for each of the analyzed fuels, by means of 0D chemical kinetic simulations using a constant pressure reactor approach. Numerical results were compared to a database of experimental measurements collected from literature. The sooting tendency threshold dependency on equivalence ratio was also investigated and the results showed that the ethanol is the less sooting among the examined fuels, while the non-oxygenated gasoline exhibited the highest soot mass and Particle Number. This paper provides a CFD-based benchmark for soot mass and Particle Number for three fuel types with largely different chemical nature.

<div class="section abstract"><div class="htmlview paragraph">In the last years, pushed by a combination of environmental concerns and technological competition with alternative powertrain architectures, internal combustion engines (ICEs) have seen a growing interest in the adoption of greener fuels. Due to increasing restrictions on ICE tailpipe emissions and loudly advertised bans of ICEs from the passenger car market, OEMs find themselves at a very important crossroad: a complete electrification of their car fleet or the adoption of disruptive solutions in the existing ICE technology, such as the use of carbon-neutral or carbon-free fuels. In this paper the authors provide a CFD assessment of both potentials and limitations of the conversion of an existing direct-injected spark-ignited (DISI) engine for high-performance applications to a hydrogen-fuelled unit. A preliminary validation of the modelling framework for the conventional gasoline fuelling is performed to reduce modelling uncertainties. Different scenarios of hydrogen fuelling are then explored to forecast potential strengths and weaknesses. Areas of hydrogen-dedicated model calibration and validation are also identified and discussed critically.</div></div>