Investigation of Gasoline Partially Premixed Combustion with External Exhaust Gas Recirculation
- Vittorio Ravaglioli ,
- Fabrizio Ponti - Universita degli Studi di Bologna, Italy ,
- Giacomo Silvagni - Universita degli Studi di Bologna, Italy ,
- Davide Moro - Universita degli Studi di Bologna, Italy ,
- Federico Stola - Marelli Europe SpA - Powertrain BU, Italy ,
- Matteo De Cesare - Marelli Europe SpA - Powertrain BU, Italy
ISSN: 1946-3936, e-ISSN: 1946-3944
Published December 27, 2021 by SAE International in United States
Citation: Ravaglioli, V., Ponti, F., Silvagni, G., Moro, D. et al., "Investigation of Gasoline Partially Premixed Combustion with External Exhaust Gas Recirculation," SAE Int. J. Engines 15(5):2022, https://doi.org/10.4271/03-15-05-0033.
The stringent emission regulations for Internal Combustion Engines (ICEs) spawned a great amount of research in the field of innovative combustion approaches characterized by high efficiency and low emissions. Previous research demonstrate that such promising techniques, named Low-Temperature Combustion (LTC), combine the benefits of Compression Ignition (CI) engines, such as high compression ratio and unthrottled lean mixture, with low engine-out emissions using a properly premixed air-fuel mixture. Due to longer ignition delay and high volatility compared to diesel, gasoline-like fuels show good potential for the generation of a highly premixed charge, which is needed to reach LTC characteristics. In this scenario, gasoline Partially Premixed Combustion (PPC), characterized by the high-pressure direct injection of gasoline, showed good potential for the simultaneous reduction of pollutants and emissions in CI engines. However, previous research on gasoline CI highlight that a key factor for the optimization of both efficiency and pollutants is the proper management of Exhaust Gas Recirculation (EGR). This work presents the experimental investigation performed running a light-duty CI engine, operated with gasoline PPC, and varying the mass of recirculated gases trapped in the combustion chamber. To guarantee the stability of gasoline autoignition in all the tested conditions, a specific experimental layout has been developed to accurately quantify the amount of trapped residual gases due to the internal and external EGR. The obtained results clearly highlight the impact of EGR on the combustion process and emissions, demonstrating that optimization of charge dilution with EGR is fundamental to guarantee the optimal compromise between efficiency and emissions over the whole operating range.