Development of the GCI combustion through a combined approach with experimental data and three-dimensional CFD simulations

The future of automotive mobility is increasingly shaped by stringent Homologation Standards, driving the development of Powertrain technologies focused on reducing emissions and improving fuel efficiency. Over the past decades, research has optimized individual components while integrating progressive electrification. A key aspect of this evolution is enhancing engine-out performance by optimizing combustion physics. Pollutant formation in Compression-Ignited (CI) engines is influenced by local mixture conditions, with high temperatures promoting Particulate Matter (PM) and Nitrogen Oxides (NOx). In Spark-Ignited (SI) engines, throttling and knock limit efficiency. Hybrid combustion regimes, particularly Low-Temperature Combustion (LTC), merge CI and SI benefits, enabling efficient, low-emission operation through controlled auto-ignition. Among LTC strategies, Gasoline Compression Ignition (GCI) has been extensively studied in this thesis. GCI utilizes multiple late-cycle injections of gasoline-like fuel in a high-compression ratio engine, generating a stratified charge that auto-ignites depending on local mixture conditions. This work presents a methodology combining experimental data and Computational Fluid Dynamics (CFD) simulations to analyze GCI combustion, structured as follows: - Engine CAD modeling: A 3D scanner captured the geometry to build a reliable moving mesh validated against test bench data. - Spray development analysis: Experimental tests in a constant-volume chamber informed CFD setup to simulate transient fuel dynamics accurately. - Droplet-wall interaction study: Tests captured the Leidenfrost effect, refining CFD modeling of fuel impingement and its impact on auto-ignition. - Combustion model validation: A sector mesh accelerated simulations, validated against extensive engine operating conditions. - GCI optimization: CFD simulations assessed injection strategies to enhance efficiency and reduce emissions, extending the engine's operational range. The findings contribute to improving CFD predictability, offering a robust tool for future Powertrains and injection systems.