Developing and Validating a Tailored Olefins Kinetics Model for Reducing Unregulated Pollutant Emissions in Diesel Engines

The emission of unregulated olefin pollutants during diesel engine combustion poses severe risks to human health and the environment. However, because of the complex nature of combustion, developing a workable olefin mechanism for numerical simulations inside engine cylinders has been difficult. Creating a reliable and accurate chemical kinetics model for olefins is crucial to coming up with effective strategies for mitigating olefin emissions. This work formulated a dependable olefin mechanism to simulate unregulated olefin emissions from diesel engines. Initially, this study employed reaction path analysis, rate of production analysis, and sensitivity analysis methods to scrutinize the formation pathways of ethylene and 1,3-butadiene. Methane, ethanol, butanol, dimethyl ether, n-heptane, and isooctane mechanisms were the basis for these investigations. After combining knowledge from the above stages, this research created an olefin mechanism that includes 50 species and 75 elementary reactions that are specifically designed for unregulated olefin pollution. Extensive validation of this mechanism against experimental results confirmed its capability to predict not only ignition delay time and laminar flame speed of diesel fuel but also the concentrations of important components like ethylene and 1,3-butadiene. Furthermore, an analysis based on a numerical investigation involving five parameters—intake temperature, intake pressure, exhaust gas recirculation rate, injection advance angle, and injection duration—provided insights into information about how to reduce emissions of ethylene and 1,3-butadiene. These emissions were successfully decreased by raising the intake temperature, injection advance angle, or shortening injection time. Conversely, there was a notable rise in the emissions of ethylene and 1,3-butadiene when the intake pressure and exhaust gas recirculation rate were increased.