Predictive Zero-Dimensional Combustion Modeling in Internal Combustion Engines With Residual Fraction and Exhaust Gas Recirculation

Abstract

The combustion process in spark ignition (SI) and compression ignition (CI) engines plays a significant role in ascertaining engine performance, efficiency, and emissions. As the automotive industry faces challenges related to energy conservation and environmental impacts, understanding and optimizing SI and CI engine combustion become paramount. This study uses a zero-dimensional (0D) internal combustion engine (ICE) model utilizing the Wiebe function to predict mass fraction burned profiles in port fuel injection (PFI) engines. The model incorporates chemical reactions of air–fuel mixtures under lean and rich combustion conditions, accounting for residual and exhaust gas recirculation (EGR). Pressure-based equilibrium constants are applied for rich combustion reactions. Further implementation of the combustion reaction model requires an accurate estimate of the combustion duration. As a result, an exploration of analogous efforts in the literature was accomplished, subsequently drawing insights. This resulted in the development of an empirical model that predicts combustion duration for various fuels such as gasoline, natural gas, propane, methanol, ethanol, hydrogen, and methane–hydrogen blends under different conditions. This includes a unique feature of spark timing variation with run-time conditions. Flame speed data, notably a maximum adiabatic flame speed at an equivalence ratio of 1.1, serve as normalization parameters. The model shows a relative fit to experimental data (R2-values: 0.729–0.972) and is explored through parametric studies, thus demonstrating its utility in simulating fuels under various engine runtime operating conditions.